Shallow planting of the rice seedlings is an important factor for getting high yield as it can increase the effective tillers on the lownode of the stem. The 2 ZB-79 shallow rice seedling transplanter combined the adv...Shallow planting of the rice seedlings is an important factor for getting high yield as it can increase the effective tillers on the lownode of the stem. The 2 ZB-79 shallow rice seedling transplanter combined the advantages of shallow planting of the seedling-casting rice transplanter and orderly planting of the traditional rice transplanter. The principle of this kind of machine is firstly to cut the standardization nursery rice seedlings with rug soil into many small pieces,and then to plant the small pieces composed of pot soil and some seedlings on it to the field surface in order,only shallowly planted on the very top part of paddy soil. Not only it can keep the performance of planting shallowly and orderly,but also simplify many mechanisms for transition,separation,and plantation of rice seedlings. It is a new type of rice seedling transplanter called laying-type up to now to get higher efficiency when working and higher yield for rice production. This paper will introduce its developing results and analyze the comparative experiments.展开更多
An automatic feeding mechanism consisting of a timing shaft,an actuating device and a clutch for feeding paper pot seedlings from a horizontal slat type chain conveyor to a horizontal pusher type chain conveyor of a v...An automatic feeding mechanism consisting of a timing shaft,an actuating device and a clutch for feeding paper pot seedlings from a horizontal slat type chain conveyor to a horizontal pusher type chain conveyor of a vegetable transplanter,was developed.The slat type chain conveyor carried the pot seedlings in upright orientation in the form of a rectangular array with each linear array of pot seedlings on a slat.The pusher type chain conveyor received a linear array of pot seedlings and delivered them to the seedling drop tube.Feeding of each linear array of pot seedlings to the pusher type conveyor at appropriate times was done using an automatic feeding mechanism.The laboratory evaluation indicated that the feeding rate of 33 to 50 pot seedlings per minute can be achieved with single set of conveyors.The feeding mechanism also worked effectively under actual field conditions with 98%to 99%of all the pot seedlings,which were properly separated and fed for planting when the forward speed of the vegetable transplanter was 0.9 km/h.The feeding mechanism has the general application of singulating rectangular array of items on the slat type chain conveyor in any industry and machine in motion on a level surface.展开更多
In order to improve the automatic sorting and transplanting of tray-seedling and reduce labors strength,a new sorting transplanter was designed.According to the feature of normal seedling tray and manual grading metho...In order to improve the automatic sorting and transplanting of tray-seedling and reduce labors strength,a new sorting transplanter was designed.According to the feature of normal seedling tray and manual grading method,the mechanical sorting procedure was defined.The key parts of sorting transplanter are as follows:an efficient transfer mechanism with aerodynamic buffer,a seedling identifying and measuring unit based on linear-structured vision,the extendible multi-grasper with wireless technology and the system controller.The experiments were conducted and showed that the transplanting success rate was 90.0% on the tray of 6×12 holes under the speed of 700 cycles per hour.The vision unit’s failed identifying rate for the superior pepper seedlings on five different trays was less than 10%,and the measurement error of seedling height was about 5 mm.展开更多
This research aimed to solve current problems in the process of maize transplanting in China such as large labor intensity,low working efficiency and poor quality.On the basis of the structure of a seedling-sprouting ...This research aimed to solve current problems in the process of maize transplanting in China such as large labor intensity,low working efficiency and poor quality.On the basis of the structure of a seedling-sprouting tray made of maize straw and the agronomic requirements of maize production,this study developed a new feeding device for such a sprouting tray,determined the dimensions of the key components in a virtual environment via Solid Edge software and obtained optimal working parameters in combination with Matlab.Some tests on field validation and maize production were conducted as well.The test results showed the importance of the working parameters on an upright degree in descending order(as well as the best working parameters)to be the vertical angle of seedling planting(13.14°),the forward speed of locomotion(0.57 m/s),and the horizontal angle of the seedling box(22.5°).The standard deviation of the field validation was 6.04%,which was within the allowable range to meet the requirements of maize transplanting.Compared with maize transplanting machines(and manual transplanting operations)on the current market,the labor inputs,as well as the rates of spacing and upright degree qualification,omitted planting and the yield using the new feeding device for automatic transplanter with maize straw seedling-sprouting trays increased 0(6.9%),0(3.1%),0(4.5%)and 0(−1.0%),respectively;whereas,the manufacturing cost was reduced by 35.5%.The results can provide a technical basis and reference for subsequent development of automatic transplanters with maize straw seedling-sprouting trays.展开更多
Rice transplanting requires the operator to manipulate the rice transplanter in straight trajectories.Various markers are proposed to help experienced drivers in keeping straightforward and parallel to the previous pa...Rice transplanting requires the operator to manipulate the rice transplanter in straight trajectories.Various markers are proposed to help experienced drivers in keeping straightforward and parallel to the previous path,which are extremely boring in terms of large-scale fields.The objective of this research was to develop an autonomous navigation system that automatically guided a rice transplanter working along predetermined paths in the field.The rice transplanter used in this research was commercially available and originally manually-operated.An automatic manipulating system was developed instead of manual functions including steering,stop,going forward and reverse.A sensor fusion algorithm was adopted to integrate measurements of the Real-Time Kinematic Global Navigation Satellite System(RTK-GNSS)and Inertial Measurement Unit(IMU),and calculate the absolute moving direction under the UTM coordinate system.A headland turning control method was proposed to ensure a robust turning process considering that the rice transplanter featured a small turning radius and a relatively large slip rate at extreme steering angles.Experiments were designed and conducted to verify the performance of the newly developed autonomous navigation system.Results showed that both lateral and heading errors were less than 8 cm and 3 degrees,respectively,in terms of following straight paths.And headland turns were robustly executed according to the required pattern.展开更多
BACKGROUND Liver transplantation(LT)is a life-saving intervention for patients with end-stage liver disease.However,the equitable allocation of scarce donor organs remains a formidable challenge.Prognostic tools are p...BACKGROUND Liver transplantation(LT)is a life-saving intervention for patients with end-stage liver disease.However,the equitable allocation of scarce donor organs remains a formidable challenge.Prognostic tools are pivotal in identifying the most suitable transplant candidates.Traditionally,scoring systems like the model for end-stage liver disease have been instrumental in this process.Nevertheless,the landscape of prognostication is undergoing a transformation with the integration of machine learning(ML)and artificial intelligence models.AIM To assess the utility of ML models in prognostication for LT,comparing their performance and reliability to established traditional scoring systems.METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines,we conducted a thorough and standardized literature search using the PubMed/MEDLINE database.Our search imposed no restrictions on publication year,age,or gender.Exclusion criteria encompassed non-English studies,review articles,case reports,conference papers,studies with missing data,or those exhibiting evident methodological flaws.RESULTS Our search yielded a total of 64 articles,with 23 meeting the inclusion criteria.Among the selected studies,60.8%originated from the United States and China combined.Only one pediatric study met the criteria.Notably,91%of the studies were published within the past five years.ML models consistently demonstrated satisfactory to excellent area under the receiver operating characteristic curve values(ranging from 0.6 to 1)across all studies,surpassing the performance of traditional scoring systems.Random forest exhibited superior predictive capabilities for 90-d mortality following LT,sepsis,and acute kidney injury(AKI).In contrast,gradient boosting excelled in predicting the risk of graft-versus-host disease,pneumonia,and AKI.CONCLUSION This study underscores the potential of ML models in guiding decisions related to allograft allocation and LT,marking a significant evolution in the field of prognostication.展开更多
To improve the precision of deep fertilization of paddy fields,a six-row centralized pneumatic deep precision fertilization device for a rice transplanter was designed.This device included a spiral fertilizer distribu...To improve the precision of deep fertilization of paddy fields,a six-row centralized pneumatic deep precision fertilization device for a rice transplanter was designed.This device included a spiral fertilizer distribution system,centralized pneumatic fertilizer delivery system,an opener system,and a fertilization control system.The centralized airflow distribution method was used in the fertilizer delivery system to ensure that the airflow in each fertilizer pipe was evenly distributed.The rotational speeds of the power take-off(PTO)and fertilizer shaft were measured synchronously using photoelectric sensors and matched proportionately in real-time using PID closed-loop control algorithms to achieve precise fertilization rates at each working speed of the rice transplanter.There were two key considerations in the design of the control system to ensure precise fertilization.Firstly,a photoelectric sensor was used to measure the speed of the PTO;the high rotational speed of the PTO could provide a high signal frequency and improve the precision of the measurement of the transplanter’s working speed.Secondly,the fertilizer shaft speed measurement subprogram was set to sleep for a short period to reduce the vibration caused by the engine.During the tests of pneumatic fertilizer delivery system,single-factor tests on airflow distribution methods were conducted.The results showed that the coefficient of variation of the airflow speed for the centralized airflow distribution method was 1.67%,which was the least among the coefficients of the three distribution methods.In the bench tests,the rotational speeds of the fertilizer shaft were set at 10 r/min,20 r/min,30 r/min,and 40 r/min.The maximum coefficient of variation of the fertilization consistency in different rows was 1.49%at the rotational speed of 20 r/min.The maximum coefficient of variation of the fertilization stability was 2.86%at the rotational speed of 40 r/min,while the average fertilizer amount per lap for each distributor was 26.25 g/r.The results of the dynamic fertilization tests showed that the maximum relative error of the fertilizer distribution amount was 2.00%when the target fertilizer rates were 20,30,and 40 kg/667 m2.The results of the field tests showed that the average relative error of the fertilization amount was 3.53%,which satisfies the design standard.This research provides a reference for optimizing pneumatic fertilizer delivery systems and improving fertilization control systems and other pneumatic precision fertilizer application devices.展开更多
The rotary plug seedling pick-up mechanism for vegetable automatic transplanter is the technical bottleneck to improve the mechanization level of vegetable planting in China.In order to solve the problems of rotary se...The rotary plug seedling pick-up mechanism for vegetable automatic transplanter is the technical bottleneck to improve the mechanization level of vegetable planting in China.In order to solve the problems of rotary seedling pick-up mechanism proposed in previous study,such as low success ratio of seedling pick-up at high speed,and interference between the seedling bowl and the end of the other seedling pick-up arm,a novel kind of rotary seedling pick-up mechanism of planetary gear train with combined type gears of incomplete denatured-eccentric-circular and non-circular gears was proposed.Through kinematic analysis of the seedling pick-up mechanism,the kinematics model was established.The computer-aided analysis and optimization software with human-computer interaction method was developed to realize parameters optimization of the seedling pick-up mechanism.Three-dimensional parametric design system of seedling pick-up mechanisms with combined non-circular gear transmission was developed for mechanism virtual simulation to verify the correctness of theoretical model and design results of the mechanism.The physical prototype of the mechanism was manufactured,and high-speed camera kinematics tests of the mechanism were conducted in the laboratory to study its kinematic characteristics.Laboratory seedling pick-up tests were carried out.The mechanism has the success ratio of seedling pick-up 96.3%without interference during seedling transporting when the rotation speed of the mechanism is 50 r/min and the seedling transplanting efficiency is 100 plants/min per row,showing that the novel mechanism has better working performance than the original one and could be applied in vegetable plug seedling transplanter.展开更多
This paper presents the study reports on evaluating a new transplanting operation by taking into accounts the interactions between soil,plant,and machine in line with the System of Rice Intensification(SRI)practices.T...This paper presents the study reports on evaluating a new transplanting operation by taking into accounts the interactions between soil,plant,and machine in line with the System of Rice Intensification(SRI)practices.The objective was to modify planting claw(kuku-kambing)of a paddy transplanter in compliance with SRI guidelines to determine the best planting spacing(S),seed rate(G)and planting pattern that results in a maximum number of seedling,tillers per hill,and yield.Two separate experiments were carried out in two different paddy fields,one to determine the best planting spacing(S=4 levels:s_(1)=0.16 m×0.3 m,s_(2)=0.18 m×0.3 m,s_(3)=0.21 m×0.3 m,and s_(4)=0.24 m×0.3 m)for a specific planting pattern(row mat or scattered planting pattern),and the other to determine the best combination of spacing with seed rate treatments(G=2 levels:g1=75 g/tray,and g2=240 g/tray).Main SRI management practices such as soil characteristics of the sites,planting depth,missing hill,hill population,the number of seedling per hill,and yield components were evaluated.Results of two-way analysis of variance with three replications showed that spacing,planting pattern and seed rate affected the number of one-seedling in all experiment.It was also observed that the increase in spacing resulted in more tillers and more panicle per plant,however hill population and sterility ratio increased with the decrease in spacing.While the maximum number of panicles were resulted from scattered planting at s_(4)=0.24 m×0.3 m spacing with the seed rate of g1=75 g/tray,the maximum number of one seedling were observed at s_(4)=0.16 m×0.3 m.The highest and lowest yields were obtained from 75 g seeds per tray scattered and 70 g seeds per tray scattered treatment respectively.For all treatments,the result clearly indicates an increase in yield with an increase in spacing.展开更多
Considering both high efficiency and high seedling standing quality is a significant objective for crop mechanized transplanting.Rape blanket seedling transplanting is an innovative and efficient transplanting techniq...Considering both high efficiency and high seedling standing quality is a significant objective for crop mechanized transplanting.Rape blanket seedling transplanting is an innovative and efficient transplanting technique.However,falling off phenomenon has become a common problem facing rape blanket seedling transplanting fields that causes seedling standing quality decrease and restricts crop growth.In this study,the rape blanket seedling of Ningza-1838 varieties and 35 d of seedling age was taken as the research object.The critical falling off equations of seedling was established by dynamic analysis.Main factors affecting seedling falling off were obtained.The critical value of each factor was calculated which were as follows:the rotation speed of the planting mechanism was 24.6 rad/s,the substrate moisture content was 50.4%and the longitudinal picking seedling quantity was 14.7 mm.Taking the seedling falling off rate as evaluation index,the measured critical value of seedling falling off was determined by high speed photography experiment.Under the condition that substrate moisture content was 55%and the longitudinal seedling quantity was 15 mm,the seedling falling off rate sharply increased when the transplanting mechanism rotation speed was increased from 24 rad/s to 26 rad/s.Under the condition that the rotation speed was 22 rad/s and the longitudinal picking seedling quantity was 15 mm,the seedling falling off rate rapidly decreased when the moisture content was increased from 47%to 53%.When moisture content exceeded 53%,this exhibited no obvious change.Under the condition that the moisture content was 50%and the rotation speed was 22 rad/s,the seedling falling off rate swiftly raised when the longitudinal picking seedling quantity was increased from 14 mm to 17 mm.The experimental results showed that the seedling falling off rate increased significantly near the critical value.The experimental results showed that the seedling falling off rate changed significantly near the critical value.It proved that the model was correct.Response surface experiments with the Box-Behnken design were conducted to determine the optimal combination parameters,which were as follows:substrate moisture content was 56.24%,planting mechanism rotation speed was 22.04 rad/s,and longitudinal picking seedling quantity was 14.91 mm.At this time,the seedling falling off rate was 1.36%,which ensured that seedlings could be transplanted stably under the carrier of seedling needle.The verification test was conducted,and the working parameters were adjusted according to the optimization results in experiment.The results of verification test were highly consistent with the optimization solution.The present study may provide a theoretical method for improving seedling standing quality of rape blanket seedling,and laid a foundation for the popularization and development of rape carpet seedling transplanting.展开更多
The chassis of rice transplanter tends to vibrate severely in the severe working environment,causing a severe effect on the operational performance and driving comfort.In order to avoid this situation,this paper const...The chassis of rice transplanter tends to vibrate severely in the severe working environment,causing a severe effect on the operational performance and driving comfort.In order to avoid this situation,this paper constructs a vibration evaluation system of the rice transplanter and carries out experimental analysis.According to the optimal acceleration sensor placement scheme,a test platform system was designed.Taking the high-speed transplanter chassis as the research object,this study carried out the experiments modal analysis and optimization on the chassis.The three-dimensional model of the transplanting machine chassis established by SolidWorks was imported into ANSYS Workbench for finite element modal simulation analysis.Comparing the two modal analyses,it is found that the results data of the two analysis methods were very close.After optimization,the length x1,the section width x2 and the thickness of the hollow beam x3 of the main load-bearing beam of the frame were as follows:x1=1641.5 mm,x2=26.7 mm,x3=5 mm,respectively.The maximum overshoot of the low-level system was reduced by 28.57%.It has been verified that the vibration of the whole machine has been effectively reduced.展开更多
To improve the low transplanting efficiencies and simplify the complex structures of current automatic transplanters,a mechanical high-speed transplanter for picking plug seedlings that is suitable for planting on pla...To improve the low transplanting efficiencies and simplify the complex structures of current automatic transplanters,a mechanical high-speed transplanter for picking plug seedlings that is suitable for planting on plastic filmswas designed.Themain components were an automatic seedling picking systemand a basket-type planting system,whichwere used for the following processes:automatic picking,planting,soil covering,and suppression of plug seedlings.The performance test was performed on the automatic transplanter with 60-day-old pepper seedlings.The transplanting efficiency was tested at speeds of 40,60,90,and 120 plants·min−1.The results showed that the coefficient of variation(CV)of the plant spacing and the missed transplanting rate increased with the planting frequency,whereas the qualified rate of planting perpendicularity and the qualified rate of planting decreasedwith the increase in the planting frequency.All planting indicesmet the JB/T 102912013 standards.The results of this study showed that the auto-transplanter could performhigh-speed transplanting on the basis of completing the following functions:automatic picking,planting,soil covering,and suppression of plug seedlings.展开更多
Background Diarrhea is a major cause of reduced growth and mortality in piglets during the suckling and weaning periods and poses a major threat to the global pig industry.Diarrhea and gut dysbiosis may in part be pre...Background Diarrhea is a major cause of reduced growth and mortality in piglets during the suckling and weaning periods and poses a major threat to the global pig industry.Diarrhea and gut dysbiosis may in part be prevented via improved early postnatal microbial colonization of the gut.To secure better postnatal gut colonization,we hypothesized that transplantation of colonic or gastric content from healthy donors to newborn recipients would prevent diarrhea in the recipients in the post-weaning period.Our objective was to examine the impact of transplanting colonic or gastric content on health and growth parameters and paraclinical parameters in recipient single-housed piglets exposed to a weaning transition and challenged with enterotoxigenic Escherichia coli(ETEC).Methods Seventy-two 1-day-old piglets were randomized to four groups:colonic microbiota transplantation(CMT,n=18),colonic content filtrate transplantation(CcFT,n=18),gastric microbiota transplantation(GMT,n=18),or saline(CON,n=18).Inoculations were given on d 2 and 3 of life,and all piglets were milk-fed until weaning(d 20)and shortly after challenged with ETEC(d 24).We assessed growth,diarrhea prevalence,ETEC concentration,organ weight,blood parameters,small intestinal morphology and histology,gut mucosal function,and microbiota composition and diversity.Results Episodes of diarrhea were seen in all groups during both the milk-and the solid-feeding phase,possibly due to stress associated with single housing.However,CcFT showed lower diarrhea prevalence on d 27,28,and 29 compared to CON(all P<0.05).CcFT also showed a lower ETEC prevalence on d 27(P<0.05).CMT showed a higher alpha diversity and a difference in beta diversity compared to CON(P<0.05).Growth and other paraclinical endpoints were similar across groups.Conclusion In conclusion,only CcFT reduced ETEC-related post-weaning diarrhea.However,the protective effect was marginal,suggesting that higher doses,more effective modalities of administration,longer treatment periods,and better donor quality should be explored by future research to optimize the protective effects of transplantation.展开更多
Intrahepatic cholangiocarcinoma(iCCA)is a rare biliary tract cancer with high mortality rate.Complete resection of the iCCA lesion is the first choice of treatment,with good prognosis after margin-negative resection.U...Intrahepatic cholangiocarcinoma(iCCA)is a rare biliary tract cancer with high mortality rate.Complete resection of the iCCA lesion is the first choice of treatment,with good prognosis after margin-negative resection.Unfortunately,only 12%-40% of patients are eligible for resection at presentation due to cirrhosis,portal hypertension,or large tumor size.Liver transplantation(LT)offers margin-negative iCCA extirpation for patients with unresectable tumors.Initially,iCCA was a contraindication for LT until size-based selection criteria were introduced to identify patients with satisfied post-LT outcomes.Recent studies have shown that tumor biology-based selection can yield high post-LT survival in patients with locally advanced iCCA.Another selection criterion is the tumor response to neoadjuvant therapy.Patients with response to neoadjuvant therapy have better outcomes after LT compared with those without tumor response to neoadjuvant therapy.Another index that helps predict the treatment outcome is the biomarker.Improved survival outcomes have also opened the door for living donor LT for iCCA.Patients undergoing LT for iCCA now have statistically similar survival rates as patients undergoing resection.The combination of surgery and locoregional and systemic therapies improves the prognosis of iCCA patients.展开更多
Background The dairy cow’s postpartum period is characterized by dramatic physiological changes,therefore imposing severe challenges on the animal for maintaining health and milk output.The dynamics of the ruminal mi...Background The dairy cow’s postpartum period is characterized by dramatic physiological changes,therefore imposing severe challenges on the animal for maintaining health and milk output.The dynamics of the ruminal microbiota are also tremendous and may play a crucial role in lactation launch.We aim to investigate the potential benefits of early microbial intervention by fresh rumen microbiota transplantation(RMT)and sterile RMT in postpartum dairy cows.Twelve fistulated peak-lactation dairy cows were selected to be the donors for rumen fluid collection.Thirty postpartum cows were divided into 3 groups as the transplantation receptors respectively receiving 10 L fresh rumen fluid(FR),10 L sterile rumen fluid(SR),or 10 L saline(CON)during 3 d after calving.Results Production performance,plasma indices,plasma lipidome,ruminal microbiome,and liver transcriptome were recorded.After fresh and sterile RMT,we found that the molar proportion of propionic acid was increased on d 7 in the FR and SR groups and the bacterial composition was also significantly changed when compared with the CON group.A similarity analysis showed that the similarities between the CON group and FR or SR group on d 7 were 48.40%or 47.85%,whereas the similarities between microbiota on d 7 and 21 in the FR and SR groups were 68.34%or 66.85%.Dry matter intake and feed efficiency were not affected by treatments.Plasmaβ-hydroxybutyrate concentration in the FR group was decreased and significantly different lipids mainly included phosphatidylcholine and lysophosphatidylcholine containing polyunsaturated fatty acids.Hepatic transcriptomics analysis indicated acutephase response pathways were upregulated in the SR group.Conclusions Our study suggests that RMT can shorten the transition process of the ruminal microbiota of postpartum dairy cows with no benefit on dry matter intake or feed efficiency.Inoculation with rumen fluid may not be a useful approach to promote the recovery of postpartum dairy cows.展开更多
Background Ginkgo biloba extract(GBE)is evidenced to be effective in the prevention and alleviation of metabolic disorders,including obesity,diabetes and fatty liver disease.However,the role of GBE in alleviating fatt...Background Ginkgo biloba extract(GBE)is evidenced to be effective in the prevention and alleviation of metabolic disorders,including obesity,diabetes and fatty liver disease.However,the role of GBE in alleviating fatty liver hemorrhagic syndrome(FLHS)in laying hens and the underlying mechanisms remain to be elucidated.Here,we investigated the effects of GBE on relieving FLHS with an emphasis on the modulatory role of GBE in chicken gut microbiota.Results The results showed that GBE treatment ameliorated biochemical blood indicators in high-fat diet(HFD)-induced FLHS laying hen model by decreasing the levels of TG,TC,ALT and ALP.The lipid accumulation and pathological score of liver were also relieved after GBE treatment.Moreover,GBE treatment enhanced the antioxidant activity of liver and serum by increasing GSH,SOD,T-AOC,GSH-PX and reducing MDA,and downregulated the expression of genes related to lipid synthesis(FAS,LXRα,GPAT1,PPARγand Ch REBP1)and inflammatory cytokines(TNF-α,IL-6,TLR4 and NF-κB)in the liver.Microbial profiling analysis revealed that GBE treatment reshaped the HFD-perturbed gut microbiota,particularly elevated the abundance of Megasphaera in the cecum.Meanwhile,targeted metabolomic analysis of SCFAs revealed that GBE treatment significantly promoted the production of total SCFAs,acetate and propionate,which were positively correlated with the GBE-enriched gut microbiota.Finally,we confirmed that the GBE-altered gut microbiota was sufficient to alleviate FLHS by fecal microbiota transplantation(FMT).Conclusions We provided evidence that GBE alleviated FLHS in HFD-induced laying hens through reshaping the composition of gut microbiota.Our findings shed light on mechanism underlying the anti-FLHS efficacy of GBE and lay foundations for future use of GBE as additive to prevent and control FLHS in laying hen industry.展开更多
Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells a...Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury microenvironment.Here,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord injury.Induced neural stem cells reprogrammed from human peripheral blood mononuclear cells,and/or thrombin plus fibrinogen,were transplanted into the lesion site of an immunosuppressed rat spinal cord injury model.Basso,Beattie and Bresnahan score,electrophysiological function,and immunofluorescence/histological analyses showed that transplantation facilitates motor and electrophysiological function,reduces lesion volume,and promotes axonal neurofilament expression at the lesion core.Examination of the graft and niche components revealed that although the graft only survived for a relatively short period(up to 15 days),it still had a crucial impact on the microenvironment.Altogether,induced neural stem cells and human fibrin reduced the number of infiltrated immune cells,biased microglia towards a regenerative M2 phenotype,and changed the cytokine expression profile at the lesion site.Graft-induced changes of the microenvironment during the acute and subacute stages might have disrupted the inflammatory cascade chain reactions,which may have exerted a long-term impact on the functional recovery of spinal cord injury rats.展开更多
Spinal cord injury is a condition in which the parenchyma of the spinal cord is damaged by trauma or various diseases.While rapid progress has been made in regenerative medicine for spinal cord injury that was previou...Spinal cord injury is a condition in which the parenchyma of the spinal cord is damaged by trauma or various diseases.While rapid progress has been made in regenerative medicine for spinal cord injury that was previously untreatable,most research in this field has focused on the early phase of incomplete injury.However,the majority of patients have chronic severe injuries;therefore,treatments for these situations are of fundamental importance.The reason why the treatment of complete spinal cord injury has not been studied is that,unlike in the early stage of incomplete spinal cord injury,there are various inhibitors of neural regeneration.Thus,we assumed that it is difficult to address all conditions with a single treatment in chronic complete spinal cord injury and that a combination of several treatments is essential to target severe pathologies.First,we established a combination therapy of cell transplantation and drug-releasing scaffolds,which contributes to functional recovery after chronic complete transection spinal cord injury,but we found that functional recovery was limited and still needs further investigation.Here,for the further development of the treatment of chronic complete spinal cord injury,we review the necessary approaches to the different pathologies based on our findings and the many studies that have been accumulated to date and discuss,with reference to the literature,which combination of treatments is most effective in achieving functional recovery.展开更多
Brain injuries due to trauma or stroke are major causes of adult death and disability.Unfortunately,few interventions are effective for post-injury repair of brain tissue.After a long debate on whether endogenous neur...Brain injuries due to trauma or stroke are major causes of adult death and disability.Unfortunately,few interventions are effective for post-injury repair of brain tissue.After a long debate on whether endogenous neurogenesis actually happens in the adult human brain,there is now substantial evidence to support its occurrence.Although neurogenesis is usually significantly stimulated by injury,the reparative potential of endogenous differentiation from neural stem/progenitor cells is usually insufficient.Alternatively,exogenous stem cell transplantation has shown promising results in animal models,but limitations such as poor long-term survival and inefficient neuronal differentiation make it still challenging for clinical use.Recently,a high focus was placed on glia-to-neuron conversion under single-factor regulation.Despite some inspiring results,the validity of this strategy is still controversial.In this review,we summarize historical findings and recent advances on neurogenesis strategies for neurorepair after brain injury.We also discuss their advantages and drawbacks,as to provide a comprehensive account of their potentials for further studies.展开更多
Parkinson’s disease is chara cterized by the loss of dopaminergic neurons in the substantia nigra pars com pacta,and although restoring striatal dopamine levels may improve symptoms,no treatment can cure or reve rse ...Parkinson’s disease is chara cterized by the loss of dopaminergic neurons in the substantia nigra pars com pacta,and although restoring striatal dopamine levels may improve symptoms,no treatment can cure or reve rse the disease itself.Stem cell therapy has a regenerative effect and is being actively studied as a candidate for the treatment of Parkinson’s disease.Mesenchymal stem cells are considered a promising option due to fewer ethical concerns,a lower risk of immune rejection,and a lower risk of teratogenicity.We performed a meta-analysis to evaluate the therapeutic effects of mesenchymal stem cells and their derivatives on motor function,memory,and preservation of dopamine rgic neurons in a Parkinson’s disease animal model.We searched bibliographic databases(PubMed/MEDLINE,Embase,CENTRAL,Scopus,and Web of Science)to identify articles and included only pee r-reviewed in vivo interve ntional animal studies published in any language through J une 28,2023.The study utilized the random-effect model to estimate the 95%confidence intervals(CI)of the standard mean differences(SMD)between the treatment and control groups.We use the systematic review center for laboratory animal expe rimentation’s risk of bias tool and the collaborative approach to meta-analysis and review of animal studies checklist for study quality assessment.A total of 33studies with data from 840 Parkinson’s disease model animals were included in the meta-analysis.Treatment with mesenchymal stem cells significantly improved motor function as assessed by the amphetamine-induced rotational test.Among the stem cell types,the bone marrow MSCs with neurotrophic factor group showed la rgest effect size(SMD[95%CI]=-6.21[-9.50 to-2.93],P=0.0001,I^(2)=0.0%).The stem cell treatment group had significantly more tyrosine hydroxylase positive dopamine rgic neurons in the striatum([95%CI]=1.04[0.59 to 1.49],P=0.0001,I^(2)=65.1%)and substantia nigra(SMD[95%CI]=1.38[0.89 to 1.87],P=0.0001,I^(2)=75.3%),indicating a protective effect on dopaminergic neurons.Subgroup analysis of the amphetamine-induced rotation test showed a significant reduction only in the intracranial-striatum route(SMD[95%CI]=-2.59[-3.25 to-1.94],P=0.0001,I^(2)=74.4%).The memory test showed significant improvement only in the intravenous route(SMD[95%CI]=4.80[1.84 to 7.76],P=0.027,I^(2)=79.6%).Mesenchymal stem cells have been shown to positively impact motor function and memory function and protect dopaminergic neurons in preclinical models of Parkinson’s disease.Further research is required to determine the optimal stem cell types,modifications,transplanted cell numbe rs,and delivery methods for these protocols.展开更多
基金Brand Discipline Construction Project of Colleges and Universities in Jiangsu Province(PPZY2015A087)
文摘Shallow planting of the rice seedlings is an important factor for getting high yield as it can increase the effective tillers on the lownode of the stem. The 2 ZB-79 shallow rice seedling transplanter combined the advantages of shallow planting of the seedling-casting rice transplanter and orderly planting of the traditional rice transplanter. The principle of this kind of machine is firstly to cut the standardization nursery rice seedlings with rug soil into many small pieces,and then to plant the small pieces composed of pot soil and some seedlings on it to the field surface in order,only shallowly planted on the very top part of paddy soil. Not only it can keep the performance of planting shallowly and orderly,but also simplify many mechanisms for transition,separation,and plantation of rice seedlings. It is a new type of rice seedling transplanter called laying-type up to now to get higher efficiency when working and higher yield for rice production. This paper will introduce its developing results and analyze the comparative experiments.
文摘An automatic feeding mechanism consisting of a timing shaft,an actuating device and a clutch for feeding paper pot seedlings from a horizontal slat type chain conveyor to a horizontal pusher type chain conveyor of a vegetable transplanter,was developed.The slat type chain conveyor carried the pot seedlings in upright orientation in the form of a rectangular array with each linear array of pot seedlings on a slat.The pusher type chain conveyor received a linear array of pot seedlings and delivered them to the seedling drop tube.Feeding of each linear array of pot seedlings to the pusher type conveyor at appropriate times was done using an automatic feeding mechanism.The laboratory evaluation indicated that the feeding rate of 33 to 50 pot seedlings per minute can be achieved with single set of conveyors.The feeding mechanism also worked effectively under actual field conditions with 98%to 99%of all the pot seedlings,which were properly separated and fed for planting when the forward speed of the vegetable transplanter was 0.9 km/h.The feeding mechanism has the general application of singulating rectangular array of items on the slat type chain conveyor in any industry and machine in motion on a level surface.
基金the National High Technology Research and Development Program of China(2012AA101903).
文摘In order to improve the automatic sorting and transplanting of tray-seedling and reduce labors strength,a new sorting transplanter was designed.According to the feature of normal seedling tray and manual grading method,the mechanical sorting procedure was defined.The key parts of sorting transplanter are as follows:an efficient transfer mechanism with aerodynamic buffer,a seedling identifying and measuring unit based on linear-structured vision,the extendible multi-grasper with wireless technology and the system controller.The experiments were conducted and showed that the transplanting success rate was 90.0% on the tray of 6×12 holes under the speed of 700 cycles per hour.The vision unit’s failed identifying rate for the superior pepper seedlings on five different trays was less than 10%,and the measurement error of seedling height was about 5 mm.
基金This study was funded by Scientific and Technological Project(Grant Number:2014BAD06 B01-1)Universities Science and Technology Innovation Team(Project Number:2014TD010)in Heilongjiang Province and Heilongjiang Land Reclamation Bureau Project(HNK125B-06-02A).
文摘This research aimed to solve current problems in the process of maize transplanting in China such as large labor intensity,low working efficiency and poor quality.On the basis of the structure of a seedling-sprouting tray made of maize straw and the agronomic requirements of maize production,this study developed a new feeding device for such a sprouting tray,determined the dimensions of the key components in a virtual environment via Solid Edge software and obtained optimal working parameters in combination with Matlab.Some tests on field validation and maize production were conducted as well.The test results showed the importance of the working parameters on an upright degree in descending order(as well as the best working parameters)to be the vertical angle of seedling planting(13.14°),the forward speed of locomotion(0.57 m/s),and the horizontal angle of the seedling box(22.5°).The standard deviation of the field validation was 6.04%,which was within the allowable range to meet the requirements of maize transplanting.Compared with maize transplanting machines(and manual transplanting operations)on the current market,the labor inputs,as well as the rates of spacing and upright degree qualification,omitted planting and the yield using the new feeding device for automatic transplanter with maize straw seedling-sprouting trays increased 0(6.9%),0(3.1%),0(4.5%)and 0(−1.0%),respectively;whereas,the manufacturing cost was reduced by 35.5%.The results can provide a technical basis and reference for subsequent development of automatic transplanters with maize straw seedling-sprouting trays.
基金This research was financially supported by National Natural Science Foundation of China(No.31501230)Shandong Province Natural Science Foundation of China for Youths(No.ZR2014CQ058)+1 种基金the National Key Research and Development Program of China Sub-project(No.2017YFD0700405)Shandong Province Science and Technology Planning Project of Higher Education(No.J17KA145).
文摘Rice transplanting requires the operator to manipulate the rice transplanter in straight trajectories.Various markers are proposed to help experienced drivers in keeping straightforward and parallel to the previous path,which are extremely boring in terms of large-scale fields.The objective of this research was to develop an autonomous navigation system that automatically guided a rice transplanter working along predetermined paths in the field.The rice transplanter used in this research was commercially available and originally manually-operated.An automatic manipulating system was developed instead of manual functions including steering,stop,going forward and reverse.A sensor fusion algorithm was adopted to integrate measurements of the Real-Time Kinematic Global Navigation Satellite System(RTK-GNSS)and Inertial Measurement Unit(IMU),and calculate the absolute moving direction under the UTM coordinate system.A headland turning control method was proposed to ensure a robust turning process considering that the rice transplanter featured a small turning radius and a relatively large slip rate at extreme steering angles.Experiments were designed and conducted to verify the performance of the newly developed autonomous navigation system.Results showed that both lateral and heading errors were less than 8 cm and 3 degrees,respectively,in terms of following straight paths.And headland turns were robustly executed according to the required pattern.
文摘BACKGROUND Liver transplantation(LT)is a life-saving intervention for patients with end-stage liver disease.However,the equitable allocation of scarce donor organs remains a formidable challenge.Prognostic tools are pivotal in identifying the most suitable transplant candidates.Traditionally,scoring systems like the model for end-stage liver disease have been instrumental in this process.Nevertheless,the landscape of prognostication is undergoing a transformation with the integration of machine learning(ML)and artificial intelligence models.AIM To assess the utility of ML models in prognostication for LT,comparing their performance and reliability to established traditional scoring systems.METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines,we conducted a thorough and standardized literature search using the PubMed/MEDLINE database.Our search imposed no restrictions on publication year,age,or gender.Exclusion criteria encompassed non-English studies,review articles,case reports,conference papers,studies with missing data,or those exhibiting evident methodological flaws.RESULTS Our search yielded a total of 64 articles,with 23 meeting the inclusion criteria.Among the selected studies,60.8%originated from the United States and China combined.Only one pediatric study met the criteria.Notably,91%of the studies were published within the past five years.ML models consistently demonstrated satisfactory to excellent area under the receiver operating characteristic curve values(ranging from 0.6 to 1)across all studies,surpassing the performance of traditional scoring systems.Random forest exhibited superior predictive capabilities for 90-d mortality following LT,sepsis,and acute kidney injury(AKI).In contrast,gradient boosting excelled in predicting the risk of graft-versus-host disease,pneumonia,and AKI.CONCLUSION This study underscores the potential of ML models in guiding decisions related to allograft allocation and LT,marking a significant evolution in the field of prognostication.
基金This research was supported by the National Key Research and Development Project of China(2017YFD0301404-05)and the Fundamental Research Funds for the Central Universities(2662018PY038).
文摘To improve the precision of deep fertilization of paddy fields,a six-row centralized pneumatic deep precision fertilization device for a rice transplanter was designed.This device included a spiral fertilizer distribution system,centralized pneumatic fertilizer delivery system,an opener system,and a fertilization control system.The centralized airflow distribution method was used in the fertilizer delivery system to ensure that the airflow in each fertilizer pipe was evenly distributed.The rotational speeds of the power take-off(PTO)and fertilizer shaft were measured synchronously using photoelectric sensors and matched proportionately in real-time using PID closed-loop control algorithms to achieve precise fertilization rates at each working speed of the rice transplanter.There were two key considerations in the design of the control system to ensure precise fertilization.Firstly,a photoelectric sensor was used to measure the speed of the PTO;the high rotational speed of the PTO could provide a high signal frequency and improve the precision of the measurement of the transplanter’s working speed.Secondly,the fertilizer shaft speed measurement subprogram was set to sleep for a short period to reduce the vibration caused by the engine.During the tests of pneumatic fertilizer delivery system,single-factor tests on airflow distribution methods were conducted.The results showed that the coefficient of variation of the airflow speed for the centralized airflow distribution method was 1.67%,which was the least among the coefficients of the three distribution methods.In the bench tests,the rotational speeds of the fertilizer shaft were set at 10 r/min,20 r/min,30 r/min,and 40 r/min.The maximum coefficient of variation of the fertilization consistency in different rows was 1.49%at the rotational speed of 20 r/min.The maximum coefficient of variation of the fertilization stability was 2.86%at the rotational speed of 40 r/min,while the average fertilizer amount per lap for each distributor was 26.25 g/r.The results of the dynamic fertilization tests showed that the maximum relative error of the fertilizer distribution amount was 2.00%when the target fertilizer rates were 20,30,and 40 kg/667 m2.The results of the field tests showed that the average relative error of the fertilization amount was 3.53%,which satisfies the design standard.This research provides a reference for optimizing pneumatic fertilizer delivery systems and improving fertilization control systems and other pneumatic precision fertilizer application devices.
基金The authors thank the editors and the anonymous reviewers whose constructive comments have notably contributed to the improved quality and clarity of this paper.This article was supported in part by the Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ16E05003)the Natural Key Research and Development Program of China(Project No.2017YFD0700800)and the Science Foundation of Zhejiang Sci-Tech University(Grant No.15022011-Y).
文摘The rotary plug seedling pick-up mechanism for vegetable automatic transplanter is the technical bottleneck to improve the mechanization level of vegetable planting in China.In order to solve the problems of rotary seedling pick-up mechanism proposed in previous study,such as low success ratio of seedling pick-up at high speed,and interference between the seedling bowl and the end of the other seedling pick-up arm,a novel kind of rotary seedling pick-up mechanism of planetary gear train with combined type gears of incomplete denatured-eccentric-circular and non-circular gears was proposed.Through kinematic analysis of the seedling pick-up mechanism,the kinematics model was established.The computer-aided analysis and optimization software with human-computer interaction method was developed to realize parameters optimization of the seedling pick-up mechanism.Three-dimensional parametric design system of seedling pick-up mechanisms with combined non-circular gear transmission was developed for mechanism virtual simulation to verify the correctness of theoretical model and design results of the mechanism.The physical prototype of the mechanism was manufactured,and high-speed camera kinematics tests of the mechanism were conducted in the laboratory to study its kinematic characteristics.Laboratory seedling pick-up tests were carried out.The mechanism has the success ratio of seedling pick-up 96.3%without interference during seedling transporting when the rotation speed of the mechanism is 50 r/min and the seedling transplanting efficiency is 100 plants/min per row,showing that the novel mechanism has better working performance than the original one and could be applied in vegetable plug seedling transplanter.
基金We acknowledge the financial support by the German Research Foundation and the Open Access Publication Fund of the Technische Universitaet Berlin.
文摘This paper presents the study reports on evaluating a new transplanting operation by taking into accounts the interactions between soil,plant,and machine in line with the System of Rice Intensification(SRI)practices.The objective was to modify planting claw(kuku-kambing)of a paddy transplanter in compliance with SRI guidelines to determine the best planting spacing(S),seed rate(G)and planting pattern that results in a maximum number of seedling,tillers per hill,and yield.Two separate experiments were carried out in two different paddy fields,one to determine the best planting spacing(S=4 levels:s_(1)=0.16 m×0.3 m,s_(2)=0.18 m×0.3 m,s_(3)=0.21 m×0.3 m,and s_(4)=0.24 m×0.3 m)for a specific planting pattern(row mat or scattered planting pattern),and the other to determine the best combination of spacing with seed rate treatments(G=2 levels:g1=75 g/tray,and g2=240 g/tray).Main SRI management practices such as soil characteristics of the sites,planting depth,missing hill,hill population,the number of seedling per hill,and yield components were evaluated.Results of two-way analysis of variance with three replications showed that spacing,planting pattern and seed rate affected the number of one-seedling in all experiment.It was also observed that the increase in spacing resulted in more tillers and more panicle per plant,however hill population and sterility ratio increased with the decrease in spacing.While the maximum number of panicles were resulted from scattered planting at s_(4)=0.24 m×0.3 m spacing with the seed rate of g1=75 g/tray,the maximum number of one seedling were observed at s_(4)=0.16 m×0.3 m.The highest and lowest yields were obtained from 75 g seeds per tray scattered and 70 g seeds per tray scattered treatment respectively.For all treatments,the result clearly indicates an increase in yield with an increase in spacing.
基金supported by the National Natural Science Foundation of China(51575284)the National Key Research and Development Program of China(2017YFD0700804)Funds for Modern Agricultural Industry Technology System Construction of China(CARS-13).
文摘Considering both high efficiency and high seedling standing quality is a significant objective for crop mechanized transplanting.Rape blanket seedling transplanting is an innovative and efficient transplanting technique.However,falling off phenomenon has become a common problem facing rape blanket seedling transplanting fields that causes seedling standing quality decrease and restricts crop growth.In this study,the rape blanket seedling of Ningza-1838 varieties and 35 d of seedling age was taken as the research object.The critical falling off equations of seedling was established by dynamic analysis.Main factors affecting seedling falling off were obtained.The critical value of each factor was calculated which were as follows:the rotation speed of the planting mechanism was 24.6 rad/s,the substrate moisture content was 50.4%and the longitudinal picking seedling quantity was 14.7 mm.Taking the seedling falling off rate as evaluation index,the measured critical value of seedling falling off was determined by high speed photography experiment.Under the condition that substrate moisture content was 55%and the longitudinal seedling quantity was 15 mm,the seedling falling off rate sharply increased when the transplanting mechanism rotation speed was increased from 24 rad/s to 26 rad/s.Under the condition that the rotation speed was 22 rad/s and the longitudinal picking seedling quantity was 15 mm,the seedling falling off rate rapidly decreased when the moisture content was increased from 47%to 53%.When moisture content exceeded 53%,this exhibited no obvious change.Under the condition that the moisture content was 50%and the rotation speed was 22 rad/s,the seedling falling off rate swiftly raised when the longitudinal picking seedling quantity was increased from 14 mm to 17 mm.The experimental results showed that the seedling falling off rate increased significantly near the critical value.The experimental results showed that the seedling falling off rate changed significantly near the critical value.It proved that the model was correct.Response surface experiments with the Box-Behnken design were conducted to determine the optimal combination parameters,which were as follows:substrate moisture content was 56.24%,planting mechanism rotation speed was 22.04 rad/s,and longitudinal picking seedling quantity was 14.91 mm.At this time,the seedling falling off rate was 1.36%,which ensured that seedlings could be transplanted stably under the carrier of seedling needle.The verification test was conducted,and the working parameters were adjusted according to the optimization results in experiment.The results of verification test were highly consistent with the optimization solution.The present study may provide a theoretical method for improving seedling standing quality of rape blanket seedling,and laid a foundation for the popularization and development of rape carpet seedling transplanting.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51875175)the Natural Science Foundation of Henan Province(Grant No.202300410124)+1 种基金Scientific and technological project in Henan Province(Grant No.212102110223)Special projects for industrial foundation reconstruction and high-quality development of manufacturing industry in MIIT.
文摘The chassis of rice transplanter tends to vibrate severely in the severe working environment,causing a severe effect on the operational performance and driving comfort.In order to avoid this situation,this paper constructs a vibration evaluation system of the rice transplanter and carries out experimental analysis.According to the optimal acceleration sensor placement scheme,a test platform system was designed.Taking the high-speed transplanter chassis as the research object,this study carried out the experiments modal analysis and optimization on the chassis.The three-dimensional model of the transplanting machine chassis established by SolidWorks was imported into ANSYS Workbench for finite element modal simulation analysis.Comparing the two modal analyses,it is found that the results data of the two analysis methods were very close.After optimization,the length x1,the section width x2 and the thickness of the hollow beam x3 of the main load-bearing beam of the frame were as follows:x1=1641.5 mm,x2=26.7 mm,x3=5 mm,respectively.The maximum overshoot of the low-level system was reduced by 28.57%.It has been verified that the vibration of the whole machine has been effectively reduced.
基金supported by the National Key Research Program of China(2017YFD0700800)the National Natural Science Foundation of China(50905153,51565059)+1 种基金Autonomous Region Key Research Projects(2018B01001-3)Autonomous Region Tianshan Youth Program(2017Q018).
文摘To improve the low transplanting efficiencies and simplify the complex structures of current automatic transplanters,a mechanical high-speed transplanter for picking plug seedlings that is suitable for planting on plastic filmswas designed.Themain components were an automatic seedling picking systemand a basket-type planting system,whichwere used for the following processes:automatic picking,planting,soil covering,and suppression of plug seedlings.The performance test was performed on the automatic transplanter with 60-day-old pepper seedlings.The transplanting efficiency was tested at speeds of 40,60,90,and 120 plants·min−1.The results showed that the coefficient of variation(CV)of the plant spacing and the missed transplanting rate increased with the planting frequency,whereas the qualified rate of planting perpendicularity and the qualified rate of planting decreasedwith the increase in the planting frequency.All planting indicesmet the JB/T 102912013 standards.The results of this study showed that the auto-transplanter could performhigh-speed transplanting on the basis of completing the following functions:automatic picking,planting,soil covering,and suppression of plug seedlings.
基金support by European Union's Horizon 2020 Research and Innovation Program under Grant Agreement No.862829,project AVANT-Alternatives to Veterinary ANTimicrobials.
文摘Background Diarrhea is a major cause of reduced growth and mortality in piglets during the suckling and weaning periods and poses a major threat to the global pig industry.Diarrhea and gut dysbiosis may in part be prevented via improved early postnatal microbial colonization of the gut.To secure better postnatal gut colonization,we hypothesized that transplantation of colonic or gastric content from healthy donors to newborn recipients would prevent diarrhea in the recipients in the post-weaning period.Our objective was to examine the impact of transplanting colonic or gastric content on health and growth parameters and paraclinical parameters in recipient single-housed piglets exposed to a weaning transition and challenged with enterotoxigenic Escherichia coli(ETEC).Methods Seventy-two 1-day-old piglets were randomized to four groups:colonic microbiota transplantation(CMT,n=18),colonic content filtrate transplantation(CcFT,n=18),gastric microbiota transplantation(GMT,n=18),or saline(CON,n=18).Inoculations were given on d 2 and 3 of life,and all piglets were milk-fed until weaning(d 20)and shortly after challenged with ETEC(d 24).We assessed growth,diarrhea prevalence,ETEC concentration,organ weight,blood parameters,small intestinal morphology and histology,gut mucosal function,and microbiota composition and diversity.Results Episodes of diarrhea were seen in all groups during both the milk-and the solid-feeding phase,possibly due to stress associated with single housing.However,CcFT showed lower diarrhea prevalence on d 27,28,and 29 compared to CON(all P<0.05).CcFT also showed a lower ETEC prevalence on d 27(P<0.05).CMT showed a higher alpha diversity and a difference in beta diversity compared to CON(P<0.05).Growth and other paraclinical endpoints were similar across groups.Conclusion In conclusion,only CcFT reduced ETEC-related post-weaning diarrhea.However,the protective effect was marginal,suggesting that higher doses,more effective modalities of administration,longer treatment periods,and better donor quality should be explored by future research to optimize the protective effects of transplantation.
文摘Intrahepatic cholangiocarcinoma(iCCA)is a rare biliary tract cancer with high mortality rate.Complete resection of the iCCA lesion is the first choice of treatment,with good prognosis after margin-negative resection.Unfortunately,only 12%-40% of patients are eligible for resection at presentation due to cirrhosis,portal hypertension,or large tumor size.Liver transplantation(LT)offers margin-negative iCCA extirpation for patients with unresectable tumors.Initially,iCCA was a contraindication for LT until size-based selection criteria were introduced to identify patients with satisfied post-LT outcomes.Recent studies have shown that tumor biology-based selection can yield high post-LT survival in patients with locally advanced iCCA.Another selection criterion is the tumor response to neoadjuvant therapy.Patients with response to neoadjuvant therapy have better outcomes after LT compared with those without tumor response to neoadjuvant therapy.Another index that helps predict the treatment outcome is the biomarker.Improved survival outcomes have also opened the door for living donor LT for iCCA.Patients undergoing LT for iCCA now have statistically similar survival rates as patients undergoing resection.The combination of surgery and locoregional and systemic therapies improves the prognosis of iCCA patients.
基金supported by the National Natural Science Foundation of China(32130100).
文摘Background The dairy cow’s postpartum period is characterized by dramatic physiological changes,therefore imposing severe challenges on the animal for maintaining health and milk output.The dynamics of the ruminal microbiota are also tremendous and may play a crucial role in lactation launch.We aim to investigate the potential benefits of early microbial intervention by fresh rumen microbiota transplantation(RMT)and sterile RMT in postpartum dairy cows.Twelve fistulated peak-lactation dairy cows were selected to be the donors for rumen fluid collection.Thirty postpartum cows were divided into 3 groups as the transplantation receptors respectively receiving 10 L fresh rumen fluid(FR),10 L sterile rumen fluid(SR),or 10 L saline(CON)during 3 d after calving.Results Production performance,plasma indices,plasma lipidome,ruminal microbiome,and liver transcriptome were recorded.After fresh and sterile RMT,we found that the molar proportion of propionic acid was increased on d 7 in the FR and SR groups and the bacterial composition was also significantly changed when compared with the CON group.A similarity analysis showed that the similarities between the CON group and FR or SR group on d 7 were 48.40%or 47.85%,whereas the similarities between microbiota on d 7 and 21 in the FR and SR groups were 68.34%or 66.85%.Dry matter intake and feed efficiency were not affected by treatments.Plasmaβ-hydroxybutyrate concentration in the FR group was decreased and significantly different lipids mainly included phosphatidylcholine and lysophosphatidylcholine containing polyunsaturated fatty acids.Hepatic transcriptomics analysis indicated acutephase response pathways were upregulated in the SR group.Conclusions Our study suggests that RMT can shorten the transition process of the ruminal microbiota of postpartum dairy cows with no benefit on dry matter intake or feed efficiency.Inoculation with rumen fluid may not be a useful approach to promote the recovery of postpartum dairy cows.
基金funded by the National Key Research and Development Program of China(2022YFA1304201)the Beijing Natural Science Foundation(6222032)+2 种基金the Starting Grants Program for Young Talents at China Agricultural Universitythe 2115 Talent Development Program of China Agricultural UniversityChinese Universities Scientific Fund。
文摘Background Ginkgo biloba extract(GBE)is evidenced to be effective in the prevention and alleviation of metabolic disorders,including obesity,diabetes and fatty liver disease.However,the role of GBE in alleviating fatty liver hemorrhagic syndrome(FLHS)in laying hens and the underlying mechanisms remain to be elucidated.Here,we investigated the effects of GBE on relieving FLHS with an emphasis on the modulatory role of GBE in chicken gut microbiota.Results The results showed that GBE treatment ameliorated biochemical blood indicators in high-fat diet(HFD)-induced FLHS laying hen model by decreasing the levels of TG,TC,ALT and ALP.The lipid accumulation and pathological score of liver were also relieved after GBE treatment.Moreover,GBE treatment enhanced the antioxidant activity of liver and serum by increasing GSH,SOD,T-AOC,GSH-PX and reducing MDA,and downregulated the expression of genes related to lipid synthesis(FAS,LXRα,GPAT1,PPARγand Ch REBP1)and inflammatory cytokines(TNF-α,IL-6,TLR4 and NF-κB)in the liver.Microbial profiling analysis revealed that GBE treatment reshaped the HFD-perturbed gut microbiota,particularly elevated the abundance of Megasphaera in the cecum.Meanwhile,targeted metabolomic analysis of SCFAs revealed that GBE treatment significantly promoted the production of total SCFAs,acetate and propionate,which were positively correlated with the GBE-enriched gut microbiota.Finally,we confirmed that the GBE-altered gut microbiota was sufficient to alleviate FLHS by fecal microbiota transplantation(FMT).Conclusions We provided evidence that GBE alleviated FLHS in HFD-induced laying hens through reshaping the composition of gut microbiota.Our findings shed light on mechanism underlying the anti-FLHS efficacy of GBE and lay foundations for future use of GBE as additive to prevent and control FLHS in laying hen industry.
基金supported by the Stem Cell and Translation National Key Project,No.2016YFA0101403(to ZC)the National Natural Science Foundation of China,Nos.82171250 and 81973351(to ZC)+6 种基金the Natural Science Foundation of Beijing,No.5142005(to ZC)Beijing Talents Foundation,No.2017000021223TD03(to ZC)Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan,No.CIT&TCD20180333(to ZC)Beijing Municipal Health Commission Fund,No.PXM2020_026283_000005(to ZC)Beijing One Hundred,Thousand,and Ten Thousand Talents Fund,No.2018A03(to ZC)the Royal Society-Newton Advanced Fellowship,No.NA150482(to ZC)the National Natural Science Foundation of China for Young Scientists,No.31900740(to SL)。
文摘Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury microenvironment.Here,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord injury.Induced neural stem cells reprogrammed from human peripheral blood mononuclear cells,and/or thrombin plus fibrinogen,were transplanted into the lesion site of an immunosuppressed rat spinal cord injury model.Basso,Beattie and Bresnahan score,electrophysiological function,and immunofluorescence/histological analyses showed that transplantation facilitates motor and electrophysiological function,reduces lesion volume,and promotes axonal neurofilament expression at the lesion core.Examination of the graft and niche components revealed that although the graft only survived for a relatively short period(up to 15 days),it still had a crucial impact on the microenvironment.Altogether,induced neural stem cells and human fibrin reduced the number of infiltrated immune cells,biased microglia towards a regenerative M2 phenotype,and changed the cytokine expression profile at the lesion site.Graft-induced changes of the microenvironment during the acute and subacute stages might have disrupted the inflammatory cascade chain reactions,which may have exerted a long-term impact on the functional recovery of spinal cord injury rats.
文摘Spinal cord injury is a condition in which the parenchyma of the spinal cord is damaged by trauma or various diseases.While rapid progress has been made in regenerative medicine for spinal cord injury that was previously untreatable,most research in this field has focused on the early phase of incomplete injury.However,the majority of patients have chronic severe injuries;therefore,treatments for these situations are of fundamental importance.The reason why the treatment of complete spinal cord injury has not been studied is that,unlike in the early stage of incomplete spinal cord injury,there are various inhibitors of neural regeneration.Thus,we assumed that it is difficult to address all conditions with a single treatment in chronic complete spinal cord injury and that a combination of several treatments is essential to target severe pathologies.First,we established a combination therapy of cell transplantation and drug-releasing scaffolds,which contributes to functional recovery after chronic complete transection spinal cord injury,but we found that functional recovery was limited and still needs further investigation.Here,for the further development of the treatment of chronic complete spinal cord injury,we review the necessary approaches to the different pathologies based on our findings and the many studies that have been accumulated to date and discuss,with reference to the literature,which combination of treatments is most effective in achieving functional recovery.
基金supported by the SIAT Innovation Program for Excellent Young Researchers,No.E1G0241001(to XZ)。
文摘Brain injuries due to trauma or stroke are major causes of adult death and disability.Unfortunately,few interventions are effective for post-injury repair of brain tissue.After a long debate on whether endogenous neurogenesis actually happens in the adult human brain,there is now substantial evidence to support its occurrence.Although neurogenesis is usually significantly stimulated by injury,the reparative potential of endogenous differentiation from neural stem/progenitor cells is usually insufficient.Alternatively,exogenous stem cell transplantation has shown promising results in animal models,but limitations such as poor long-term survival and inefficient neuronal differentiation make it still challenging for clinical use.Recently,a high focus was placed on glia-to-neuron conversion under single-factor regulation.Despite some inspiring results,the validity of this strategy is still controversial.In this review,we summarize historical findings and recent advances on neurogenesis strategies for neurorepair after brain injury.We also discuss their advantages and drawbacks,as to provide a comprehensive account of their potentials for further studies.
文摘Parkinson’s disease is chara cterized by the loss of dopaminergic neurons in the substantia nigra pars com pacta,and although restoring striatal dopamine levels may improve symptoms,no treatment can cure or reve rse the disease itself.Stem cell therapy has a regenerative effect and is being actively studied as a candidate for the treatment of Parkinson’s disease.Mesenchymal stem cells are considered a promising option due to fewer ethical concerns,a lower risk of immune rejection,and a lower risk of teratogenicity.We performed a meta-analysis to evaluate the therapeutic effects of mesenchymal stem cells and their derivatives on motor function,memory,and preservation of dopamine rgic neurons in a Parkinson’s disease animal model.We searched bibliographic databases(PubMed/MEDLINE,Embase,CENTRAL,Scopus,and Web of Science)to identify articles and included only pee r-reviewed in vivo interve ntional animal studies published in any language through J une 28,2023.The study utilized the random-effect model to estimate the 95%confidence intervals(CI)of the standard mean differences(SMD)between the treatment and control groups.We use the systematic review center for laboratory animal expe rimentation’s risk of bias tool and the collaborative approach to meta-analysis and review of animal studies checklist for study quality assessment.A total of 33studies with data from 840 Parkinson’s disease model animals were included in the meta-analysis.Treatment with mesenchymal stem cells significantly improved motor function as assessed by the amphetamine-induced rotational test.Among the stem cell types,the bone marrow MSCs with neurotrophic factor group showed la rgest effect size(SMD[95%CI]=-6.21[-9.50 to-2.93],P=0.0001,I^(2)=0.0%).The stem cell treatment group had significantly more tyrosine hydroxylase positive dopamine rgic neurons in the striatum([95%CI]=1.04[0.59 to 1.49],P=0.0001,I^(2)=65.1%)and substantia nigra(SMD[95%CI]=1.38[0.89 to 1.87],P=0.0001,I^(2)=75.3%),indicating a protective effect on dopaminergic neurons.Subgroup analysis of the amphetamine-induced rotation test showed a significant reduction only in the intracranial-striatum route(SMD[95%CI]=-2.59[-3.25 to-1.94],P=0.0001,I^(2)=74.4%).The memory test showed significant improvement only in the intravenous route(SMD[95%CI]=4.80[1.84 to 7.76],P=0.027,I^(2)=79.6%).Mesenchymal stem cells have been shown to positively impact motor function and memory function and protect dopaminergic neurons in preclinical models of Parkinson’s disease.Further research is required to determine the optimal stem cell types,modifications,transplanted cell numbe rs,and delivery methods for these protocols.
