Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly ...Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1and σ2for R1(ratio of the PBA mass loss to the material total mass except the PBA) and R2(ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleumbased PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1= kω, where k is a variable related to PBA’s own attributes.展开更多
BACKGROUND Pyogenic granuloma(PG)is a localized,reddish and vascularized hyperplastic lesion of the connective tissue which occurs in the oral cavity.In most cases,the presence of this lesion does not show alveolar bo...BACKGROUND Pyogenic granuloma(PG)is a localized,reddish and vascularized hyperplastic lesion of the connective tissue which occurs in the oral cavity.In most cases,the presence of this lesion does not show alveolar bone resorption.The pathology is diagnosed clinically with some caution.However,the diagnosis and treatment are usually corroborated with histopathological evidence.CASE SUMMARY Three clinical cases of PG associated with bone loss were described in this study.The three patients presented tumor-like growth which bled on touch,and were associated with local irritant factors.Radiographs showed bone loss.All cases were treated with conservative surgical excision.The scarring was satisfactory,and there was no case of recurrence.The diagnoses were based on clinical findings,and were confirmed histopathologically.CONCLUSION The occurrence of oral PG with bone loss is unusual.Therefore,clinical and radiographic evaluations are important for the diagnosis.展开更多
[Objectives]To investigate the preventive effects of Wumen Gumi Bao Decoction(WMGBD)on estrogen deficiency-induced bone loss.[Methods]Three-month-old Sprague-Dawley rats were ovariectomized(OVX)and then treated with W...[Objectives]To investigate the preventive effects of Wumen Gumi Bao Decoction(WMGBD)on estrogen deficiency-induced bone loss.[Methods]Three-month-old Sprague-Dawley rats were ovariectomized(OVX)and then treated with WMGBD,and their admixtures for six weeks.The bone trabecular microstructure,bone histopathological examination were determined in the rat femur tissue,and serum biomarkers of bone formation and resorption were analyzed by ELISA,and the protein expressions of Wnt3a,β-catenin,and phosphorylatedβ-catenin(p-β-catenin)were analyzed by Western blot.Statistical analysis was conducted by using one-way analysis of variance(ANOVA)followed by LSD post hoc analysis or independent samples t test using the scientific statistic software SPSS version 20.0.[Results]WMGBD could promote osteosis and ameliorate bone loss to improve the repair of cracked bone trabeculae of OVX rats.Furthermore,WMGBD also could prevent OVX-induced decrease in collagen fibers in the femoral tissue of ovariectomized rats and promote the regeneration of new bone or cartilage tissue,while WMGBD could activate the Wnt3a/β-catenin pathway.[Conclusions]WMGBD could ameliorate estrogen deficiency-induced bone loss via the regulation of Wnt3a/β-catenin pathway.展开更多
The traditional Chinese medicine of Radix Hedysari plays an important role in invigorating gas for ascending, benefiting blood for promoting production of fluid, and promoting circulation for removing obstruction in c...The traditional Chinese medicine of Radix Hedysari plays an important role in invigorating gas for ascending, benefiting blood for promoting production of fluid, and promoting circulation for removing obstruction in collaterals, which is consistent with the principle of treatment for osteoporosis. This study is designed to investigate the bioactive components on increasing peak bone mass (PBM) by exploring the spectrum-effect relationship between chromatography fingerprints and effect. Multiple indicators are selected to evaluate the pharmacological activity. In fingerprints, 21 common peaks are obtained, five of which are identified. Furthermore, gray relational analysis (GRA) is a quantitative method of gray system theory and is used to describe the correlation degree of common peaks and pharmacological activities with relational value. 21 components are then divided into three different regions, of which ononin and calycosin play an extremely significant role in increasing PBM. In addition, factor analysis and hierarchical cluster analysis (HCA) are used to screen the optimal producing area for Radix Hedysari. This provides a comprehensive and efficient method to improve the quality evaluation of Radix Hedysari, confirming the bioactive components for PBM-enhancement and further develop its medicinal value.展开更多
The management of recurrent anterior gleno-humeral joint instability is challenging in the presence of boneloss.It is often seen in young athletic patients and dislocations related to epileptic seizures and may involv...The management of recurrent anterior gleno-humeral joint instability is challenging in the presence of boneloss.It is often seen in young athletic patients and dislocations related to epileptic seizures and may involve glenoid bone deficiency,humeral bone deficiency or combined bipolar lesions.It is critical to accurately identify and assess the amount and position of bone loss in order to select the most appropriate treatment and reduce the risk of recurrent instability after surgery.The current literature suggests that coracoid and iliac crest bone block transfers are reliable for treating glenoid defects.The treatment of humeral defects is more controversial,however,although good early results have been reported after arthroscopic Remplissage for small defects.Larger humeral defects may require complex reconstruction or partial resurfacing.There is currently very limited evidence to support treatment strategies when dealing with bipolar lesions.The aim of this review is to summarise the current evidence regarding the best imaging modalities and treatment strategies in managing this complex problem relating particularly to contact athletes and dislocations related to epileptic seizures.展开更多
The number of revision total hip arthroplasties is expected to rise as the indications for arthroplasty will expand due to the aging population. The prevalence of extensive proximal femoral bone loss is expected to in...The number of revision total hip arthroplasties is expected to rise as the indications for arthroplasty will expand due to the aging population. The prevalence of extensive proximal femoral bone loss is expected to increase subsequently. The etiology of bone loss from the proximal femur after total hip arthroplasty is multifactorial. Stress shielding, massive osteolysis, extensive loosening and history of multiple surgeries consist the most common etiologies. Reconstruction of extensive bone loss of the proximal femur during a revision hip arthroplasty is a major challenge for even the most experienced orthopaedic surgeon. The amount of femoral bone loss and the bone quality of the remaining metaphyseal and diaphyseal bone dictate the selection of appropriate reconstructive option. These include the use of impaction allografting, distal press-fit fixation, allograft-prosthesis composites and tumor megaprostheses. This review article is a concise review of the current literature and provides an algorithmic approachfor reconstruction of different types of proximal femoral bone defects.展开更多
AIM To study the clinical findings and characteristic features in sciatic notch dumbbell tumors(SNDTs).METHODS We retrospectively reviewed the clinical outcomes and characteristic features of consecutive cases of SNDT...AIM To study the clinical findings and characteristic features in sciatic notch dumbbell tumors(SNDTs).METHODS We retrospectively reviewed the clinical outcomes and characteristic features of consecutive cases of SNDTs(n = 8). RESULTS Buttock masses occurred in three patients with SNDT(37.5%). Severe buttock tenderness and pain at rest were observed in seven patients with SNDTs(87.5%). Remarkably, none of the patients with SNDTs experienced back pain. Mean tumor size was 8.4 ± 2.0 cm(range, 3.9 to 10.6 cm) and part of the tumor mass was detected in 2 patients in the sagittal view of lumbar magnetic resonance imaging(MRI).CONCLUSION The clinical information regarding to SNDTs is scarce. The authors consider that above mentioned characteristic findings may facilitate the suspicion of pelvic pathology and a search for SNDT by MRI or computed tomography should be considered in patients presenting with sciatica without evidence of spinal diseases.展开更多
Background:The effect of platelet factor 4(PF4)on bone marrow mesenchymal stem cells(BMMSCs)and osteoporosis is poorly understood.Therefore,this study aimed to evaluate the effects of PF4-triggered bone destruction in...Background:The effect of platelet factor 4(PF4)on bone marrow mesenchymal stem cells(BMMSCs)and osteoporosis is poorly understood.Therefore,this study aimed to evaluate the effects of PF4-triggered bone destruction in mice and determine the underlying mechanism.Methods:First,in vitro cell proliferation and cell cycle of BMMSCs were assessed using a CCK8 assay and flow cytometry,respectively.Osteogenic differentiation was confirmed using staining and quantification of alkaline phosphatase and Alizarin Red S.Next,an osteoporotic mouse model was established by performing bilateral ovariectomy(OVX).Furthermore,the PF4 concentrations were obtained using enzymelinked immunosorbent assay.The bone microarchitecture of the femur was evaluated using microCT and histological analyses.Finally,the key regulators of osteogenesis and pathways were investigated using quantitative real-time polymerase chain reaction and Western blotting.Results:Human PF4 widely and moderately decreased the cell proliferation and osteogenic differentiation ability of BMMSCs.Furthermore,the levels of PF4 in the serum and bone marrow were generally increased,whereas bone microarchitecture deteriorated due to OVX.Moreover,in vivo mouse PF4 supplementation triggered bone deterioration of the femur.In addition,several key regulators of osteogenesis were downregulated,and the integrinα5-focal adhesion kinase-extracellular signalregulated kinase(ITGA5-FAK-ERK)pathway was inhibited due to PF4 supplementation.Conclusions:PF4 may be attributed to OVX-i nduced bone loss triggered by the suppression of bone formation in vivo and alleviate BMMSC osteogenic differentiation by inhibiting the ITGA5-FAK-ERK pathway.展开更多
The kintic and activation energy of mass loss of two grades of melted TNT explosive, grade A and grade B, with freezing points of 80.57 and 78.15 ℃, respectively, were studied by isothermal and nonisothermal gravimet...The kintic and activation energy of mass loss of two grades of melted TNT explosive, grade A and grade B, with freezing points of 80.57 and 78.15 ℃, respectively, were studied by isothermal and nonisothermal gravimetric methods. In isothermal method, the mass loss of samples in containers of glass and aluminum was followed in temperatures of 80, 90 and 100 ℃. The kinetic of the mass loss of the samples in the aluminum container was higher than the kinetic of it in the glass container that can be related to the effects of heat transfer and catalytic of aluminm metal. Also, the presence of impurities in grade B was due to increasing of kinetic of mass loss of it versus grade A. The non-isothermal curves were obtained in range of 30-330 ℃ at heating rates of 10,15 and 20 ℃·min^(-1).The TG/DTG data were used for determination of activation energy(E_a) of mass loss of TNT samples upon degradation by using Ozawa, Kissinger, Ozawa-Flynn-Wall(OFW) and Kissinger-Akahira-Sunose(KAS) methods as model free methods. The activation energies of grades of A and B of TNT was obtained 99-120 and 66-70 kJ mol^(-1)respectively. The lower values of activation energy of the degradation reaction of grade B confirm the effect of impurities in the kinetics of mass loss of this grade.展开更多
Displacement-monitoring-based back analysis is a popular method for geomechanical parameter estimation.However,due to the delayed installation of multi-point extensometers,the monitoring curve is only a part of the ov...Displacement-monitoring-based back analysis is a popular method for geomechanical parameter estimation.However,due to the delayed installation of multi-point extensometers,the monitoring curve is only a part of the overall one,leading to displacement loss.Besides,the monitoring and construction time on the monitoring curve is difficult to determine.In the literature,the final displacement was selected for the back analysis,which could induce unreliable results.In this paper,a displacement-based back analysis method to mitigate the influence of displacement loss is developed.A robust hybrid optimization algorithm is proposed as a substitute for time-consuming numerical simulation.It integrates the strengths of the nonlinear mapping and prediction capability of the support vector machine(SVM)algorithm,the global searching and optimization characteristics of the optimized particle swarm optimization(OPSO)algorithm,and the nonlinear numerical simulation capability of ABAQUS.To avoid being trapped in the local optimum and to improve the efficiency of optimization,the standard PSO algorithm is improved and is compared with other three algorithms(genetic algorithm(GA),simulated annealing(SA),and standard PSO).The results indicate the superiority of OPSO algorithm.Finally,the hybrid optimization algorithm is applied to an engineering project.The back-analyzed parameters are submitted to numerical analysis,and comparison between the calculated and monitoring displacement curve shows that this hybrid algorithm can offer a reasonable reference for geomechanical parameters estimation.展开更多
Background:Escherichia coli(E.coli)infection in humans and animals usually comes with gut dysbiosis,which is potential culprit to skeletal health,it is still unclear to whether diet interfered gut microbiome changes c...Background:Escherichia coli(E.coli)infection in humans and animals usually comes with gut dysbiosis,which is potential culprit to skeletal health,it is still unclear to whether diet interfered gut microbiome changes can be a protective strategy to bone loss development.Here,the effects of resistant starch from raw potato starch(RPS),a type of prebiotic,on E.coli-induced bone loss and gut microbial composition in meat ducks were evaluated.Results:The results showed that dietary 12%RPS treatment improved bone quality,depressed bone resorption,and attenuated the pro-inflammatory reaction in both ileum and bone marrow.Meanwhile,the 12%RPS diet also increased the abundance of Firmicutes in E.coli-treated birds,along with higher production of short-chain fatty acids(SCFAs)especially propionate and butyrate.Whereas addition ofβ-acid,an inhibitor of bacterial SCFAs production,to the drinking water of ducks fed 12%RPS diet significantly decreased SCFAs level in cecum content and eliminated RPS-induced tibial mass improvement.Further,treatment with MI-2 to abrogate mucosa-associated lymphoid tissue lymphoma translocation protein 1(Malt1)activity replicated the protective role of dietary 12%RPS in E.coli-induced bone loss including reduced the inhibition on nuclear factorκB(NF-κB)inflammasome activation,decreased bone resorption,and improved bone quality,which were correlated with comparable and higher regulatory T cells(Treg)frequency in MI-2 and 12%RPS group,respectively.Conclusions:These findings suggested that the diet with 12%RPS could alleviate E.coli-induced bone loss in meat ducks by changing the gut microbial composition and promoting concomitant SCFAs production,and consequently inhibiting Malt1/NF-κB inflammasome activation and Treg cells expansion.展开更多
Earth penetration weapon(EPW) is applicable for attacking underground targets protected by reinforced concrete and rocks.With increasing impact velocity,the mass loss/abrasion of penetrator increases,which significant...Earth penetration weapon(EPW) is applicable for attacking underground targets protected by reinforced concrete and rocks.With increasing impact velocity,the mass loss/abrasion of penetrator increases,which significantly decreases the penetration efficiency due to the change of nose shape.The abrasion may induce instability of the penetrator,and lead to failure of its structure.A common disadvantage,i.e.dependence on corresponding experimental results,exists in all the available formulae,which limits their ranges of application in estimating the mass loss of penetrator.In this paper,we conduct a parametric study on the mass loss of penetrator,and indicate that the mass loss of penetrator can be determined by seven variables,i.e.,the initial impact velocity,initial nose shape,melting heat,shank diameter of projectile and density and strength of target as well as the aggregate hardness of target.Further discussion on factors dominant in the mass abrasion of penetrator are given,which may be helpful for optimizing the target or the projectile for defensive or offensive objectives,respectively.展开更多
With increasing aging population,osteoporosis has emerged as a public health problem worldwide.Epidemiological data reveal that the prevalence of osteoporosis in cold regions is high,and low temperatures may crucially...With increasing aging population,osteoporosis has emerged as a public health problem worldwide.Epidemiological data reveal that the prevalence of osteoporosis in cold regions is high,and low temperatures may crucially affect bone mass.Recent studies have found that the transient receptor potential melastatin-8(TRPM8)channel,a cold-sensitive ion channel,can sense cold environment,and can be activated in cold environment.It may play an antagonistic role in low temperature-induced bone mass reduction.Mechanistically,this function may be ascribed to the activation of TRPM8 channel proteins in human bone marrow mesenchymal stem cells(hBM-MSCs),which causes osteoblast differentiation and mineralization in the bone.TRPM8 channel on the surface of brown adipocytes participates in the thermogenesis in brown adipose tissue(BAT)and the regulation of whole-body energy balance to maintain bone homeostasis.TRPM8 may be involved in bone remodeling throughout life.This paper reviews recent research on the possible antagonistic mechanism of TRPM8 in signaling pathways related to low temperature-induced bone mass loss and assesses the possibility of TRPM8 as a molecular target for the prevention and treatment of low temperature-induced osteoporosis in cold regions.展开更多
BACKGROUND The prevalence of osteoporosis and low bone mass is steadily rising each year.Low body weight is commonly linked to diminished bone mass and serves as a robust predictor of osteoporosis.Nonetheless,the conn...BACKGROUND The prevalence of osteoporosis and low bone mass is steadily rising each year.Low body weight is commonly linked to diminished bone mass and serves as a robust predictor of osteoporosis.Nonetheless,the connection between body mass index(BMI),bone mineral density,and lipid profiles among the elderly remains elusive.AIM To examine the association between BMI and bone mass,explore the correlation between lipid profiles and bone mass,and delve into the interplay between lipid metabolism and bone health.METHODS The study included 520 patients aged≥65 years(178 men and 342 women).Age,sex,weight,and height were recorded.Femoral neck bone mineral density and T scores were determined using a dual-energy X-ray absorptiometry scanner.Blood calcium(Ca),phosphorus(P),albumin(ALB),alkaline phosphatase(ALP),aspartate aminotransferase,alanine aminotransferase,triglyceride(TG),total cholesterol(TC),high-density lipoprotein(HDL)and low-density lipoprotein(LDL)levels were measured.Patients were classified by sex(male and female),age(65-79 years and≥80 years),and T score(normal bone mineral density,osteopenia and osteoporosis).RESULTS Age,sex,BMI,and ALP and TG levels were independent risk factors for osteoporosis.For the 65-79-and≥80-yearold groups,females presented lower T scores than males.Ca,P,ALB,ALP,TC,HDL and LDL levels were significantly different between men and women in the 65-79-year-old group.In addition,BMI and TG levels were significantly decreased in osteoporotic patients compared with patients with normal bone mass.TC levels declined in 65-to 79-year-old male and female osteoporosis patients.In the group of women aged≥80 years,osteoporotic patients showed significantly increased ALP levels.Furthermore,we found positive correlations between BMI and TG levels in the male and female patient groups.However,we found no significant differences in ALB,Ca,P,HDL and LDL levels in osteoporotic patients compared to patients with normal bone mass.CONCLUSION Osteoporotic patients showed significantly decreased BMI and TG levels compared with those with normal bone mass.BMI showed positive correlations with TG levels in male and female patients.These results indicate correlations between BMI and bone mass and between lipid profiles and bone mass.展开更多
BACKGROUND Tranexamic acid(TXA)has been used as an anti-fibrinolytic drug for over half a century and has received much attention in recent decades.AIM To evaluate the efficacy of topical vs intravenous TXA in reducin...BACKGROUND Tranexamic acid(TXA)has been used as an anti-fibrinolytic drug for over half a century and has received much attention in recent decades.AIM To evaluate the efficacy of topical vs intravenous TXA in reducing blood loss and promoting wound healing in bone surgery.METHODS From the electronic resources,PubMed,Cochrane Library,Embase,ISI,and Scopus were used to perform a literature search over the last 10 years between 2010 and 2020.EndNote™X8 was used for managing the electronic resource.Searches were performed with mesh terms.The data were retracted blindly by two independent reviewers.Random effects were used to deal with potential heterogeneity and I2 showed heterogeneity.Chi-square(I2)tests were used to quantify the extent of heterogeneity(P<0.01 was considered statistically significant).The efficacy of topical TXA in reducing blood loss and promoting wound healing in bone surgery was compared with intravenous TXA and placebo.RESULTS According to the research design,1360 potentially important research abstracts and titles were discovered in our electronic searches,and 18 papers remained in agreement with our inclusion criteria.It was found that TXA reduced 277.51 mL of blood loss compared to placebo,and there was no significant difference between topical TXA and IV TXA in reducing blood loss in bone surgery.Our analyses also showed that TXA significantly reduced blood transfusion compared to placebo and there was no significant difference between topical TXA and IV TXA.CONCLUSION The use of both topical and intravenous TXA are equally effective in reducing blood loss in bone surgery,which might be beneficial for wound healing after surgery.展开更多
Objective To better understand the pathological causes of bone loss in a space environment, including microgravity, ionizing radiation, and ultradian rhythms. Methods Sprague Dawley(SD) rats were randomly divided into...Objective To better understand the pathological causes of bone loss in a space environment, including microgravity, ionizing radiation, and ultradian rhythms. Methods Sprague Dawley(SD) rats were randomly divided into a baseline group, a control group, a hindlimb suspension group, a radiation group, a ultradian rhythms group and a combined-three-factor group. After four weeks of hindlimb suspension followed by X-ray exposure and/or ultradian rhythms, biomechanical properties, bone mineral density, histological analysis, microstructure parameters, and bone turnover markers were detected to evaluate bone loss in hindlimbs of rats. Results Simulated microgravity or combined-three factors treatment led to a significant decrease in the biomechanical properties of bones, reduction in bone mineral density, and deterioration of trabecular parameters. Ionizing radiation exposure also showed adverse impact while ultradian rhythms had no significant effect on these outcomes. Decrease in the concentration of the turnover markers bone alkaline phosphatase(b ALP), osteocalcin(OCN), and tartrate-resistant acid phosphatase-5 b(TRAP-5 b) in serum was in line with the changes in trabecular parameters. Conclusion Simulated microgravity is the main contributor of bone loss. Radiation also results in deleterious effects but ultradian rhythms has no significant effect. Combined-three factors treatment do not exacerbate bone loss when compared to simulated microgravity treatment alone.展开更多
The mass loss and nose blunting of a projectile during high-speed deep penetration into concrete target may cause structural destruction and ballistic trajectory instability of the penetrator,obviously reducing the pe...The mass loss and nose blunting of a projectile during high-speed deep penetration into concrete target may cause structural destruction and ballistic trajectory instability of the penetrator,obviously reducing the penetration efficiency of penetrator.Provided that the work of friction between projectile and target is totally transformed into the heat to melt penetrator material at its nose surface,an engineering model is established for the mass loss and nose-blunting of the ogive-nosed projectile.A dimensionless formula for the relative mass loss of projectile is obtained by introducing the dimensionless impact function I and geometry function N of the projectile.The critical value V c0of the initial striking velocity is formulated,and the mass loss of projectile tends to increase weakly nonlinearly with I/N when V0>V c0,whilst the mass loss is proportional to the initial kinetic energy of projectile when V0<V c0.The theoretical prediction of V c0is further confirmed to be very close to the experimental value of 1.0 km/s based on 11 sets of different penetration tests.Also the validity of the proposed expressions of massloss and nose-blunting coefficients of a projectile are verified by the tests.Therefore,a theoretical basis is for the empirical conclusions drawn in previous publications.Regarding the completely empirical determinations of the mass loss and nose-blunting coefficients given in previous papers,the present analysis reveals its physical characteristic and also guarantees its prediction accuracy.The engineering model established in the present paper forms the basis for further discussions on the structural stability and the terminal ballistic stability of ogive-nosed projectiles high-speed penetrating into concrete targets,which will respectively be elaborated in Part II and Part III of the present study.展开更多
Hypoxia(low oxygen level) is an important feature during infections and affects the host defence mechanisms. The host has evolved specific responses to address hypoxia, which are strongly dependent on the activation o...Hypoxia(low oxygen level) is an important feature during infections and affects the host defence mechanisms. The host has evolved specific responses to address hypoxia, which are strongly dependent on the activation of hypoxia-inducible factor 1(HIF-1).Hypoxia interferes degradation of HIF-1 alpha subunit(HIF-1α), leading to stabilisation of HIF-1α, heterodimerization with HIF-1 beta subunit(HIF-1β) and subsequent activation of HIF-1 pathway. Apical periodontitis(periapical lesion) is a consequence of endodontic infection and ultimately results in destruction of tooth-supporting tissue, including alveolar bone. Thus far, the role of HIF-1 in periapical lesions has not been systematically examined. In the present study, we determined the role of HIF-1 in a wellcharacterised mouse periapical lesion model using two HIF-1α-activating strategies, dimethyloxalylglycine(DMOG) and adenovirusinduced constitutively active HIF-1α(CA-HIF1 A). Both DMOG and CA-HIF1 A attenuated periapical inflammation and tissue destruction. The attenuation in vivo was associated with downregulation of nuclear factor-κappa B(NF-κB) and osteoclastic gene expressions. These two agents also suppressed NF-κB activation and subsequent production of proinflammatory cytokines by macrophages. Furthermore, activation of HIF-1α by DMOG specifically suppressed lipopolysaccharide-stimulated macrophage differentiation into M1 cells, increasing the ratio of M2 macrophages against M1 cells. Taken together, our data indicated that activation of HIF-1 plays a protective role in the development of apical periodontitis via downregulation of NF-κB, proinflammatory cytokines, M1 macrophages and osteoclastogenesis.展开更多
Background:Cachexia is a metabolic state with weight and muscle mass loss as its basic characteristics.This study aims to reveal the influ-ence of weight loss on the progression of cancer cachexia,and to determine its...Background:Cachexia is a metabolic state with weight and muscle mass loss as its basic characteristics.This study aims to reveal the influ-ence of weight loss on the progression of cancer cachexia,and to determine its impact on the patient prognosis.Methods:A total of 2990 cancer patients were enrolled in this retrospective study.Demographic information,clinical materials,and follow-up data were collected for all patients.A receiver operating characteristic curve was used to determine threshold values for weight loss within the past six months(WL).Kaplan-Meier curves and Cox proportional hazard regression models were adopted for survival analyses.Results:After excluding ineligible patients,2480 patients were included in the analysis,705(28.4%)of whom were considered to be ca-chexic.A WL of 10%was determined to be the optimal threshold for diagnosing malnutrition according to the Patient-Generated Subjective Global Assessment.Notably,WL>10%was a predictor of survival outcomes only in the general population(HR=1.218,95%Cl=1.002-1.481,P=0.048),but not in the cachexic population,based on the multivariable Cox regression model.A larger proportion of cachexic pa-tients with WL>10%had a nutritional risk screening 2002 score≥3(25.7%vs 13.7%,P<0.001)and a modified Glasgow Prognosis Score=2(12.8%vs 7.8%,P=0.032).No significant difference was observed in the degree of decreased muscle strength or quality of life(P>0.05).Conclusions:Weight loss is a predictor of impaired survival in the general population,but not in the cachexic population.The present study shows that cachexic patients with severe weight loss had a higher risk of malnutrition,a worse systemic inflammation status,and more severe malnutrition,but that the weight loss itself was not associated with the prognosis of these patients or the progression of their cachexia.展开更多
This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instan...This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.展开更多
文摘Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1and σ2for R1(ratio of the PBA mass loss to the material total mass except the PBA) and R2(ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleumbased PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1= kω, where k is a variable related to PBA’s own attributes.
文摘BACKGROUND Pyogenic granuloma(PG)is a localized,reddish and vascularized hyperplastic lesion of the connective tissue which occurs in the oral cavity.In most cases,the presence of this lesion does not show alveolar bone resorption.The pathology is diagnosed clinically with some caution.However,the diagnosis and treatment are usually corroborated with histopathological evidence.CASE SUMMARY Three clinical cases of PG associated with bone loss were described in this study.The three patients presented tumor-like growth which bled on touch,and were associated with local irritant factors.Radiographs showed bone loss.All cases were treated with conservative surgical excision.The scarring was satisfactory,and there was no case of recurrence.The diagnoses were based on clinical findings,and were confirmed histopathologically.CONCLUSION The occurrence of oral PG with bone loss is unusual.Therefore,clinical and radiographic evaluations are important for the diagnosis.
基金Supported by Senile Health Research Project of Jiangsu Provincial Health Commission of China(LKZ2023217)Natural Science Foundation of Nanjing University of Traditional Chinese Medicine(XAR2021041)+1 种基金Suzhou Science and Technology Development Plan Project(SYSD2020215,SKY2022202)The Ninth Batch of Suzhou Gusu Health Key Talents Project(GSWS2022107)。
文摘[Objectives]To investigate the preventive effects of Wumen Gumi Bao Decoction(WMGBD)on estrogen deficiency-induced bone loss.[Methods]Three-month-old Sprague-Dawley rats were ovariectomized(OVX)and then treated with WMGBD,and their admixtures for six weeks.The bone trabecular microstructure,bone histopathological examination were determined in the rat femur tissue,and serum biomarkers of bone formation and resorption were analyzed by ELISA,and the protein expressions of Wnt3a,β-catenin,and phosphorylatedβ-catenin(p-β-catenin)were analyzed by Western blot.Statistical analysis was conducted by using one-way analysis of variance(ANOVA)followed by LSD post hoc analysis or independent samples t test using the scientific statistic software SPSS version 20.0.[Results]WMGBD could promote osteosis and ameliorate bone loss to improve the repair of cracked bone trabeculae of OVX rats.Furthermore,WMGBD also could prevent OVX-induced decrease in collagen fibers in the femoral tissue of ovariectomized rats and promote the regeneration of new bone or cartilage tissue,while WMGBD could activate the Wnt3a/β-catenin pathway.[Conclusions]WMGBD could ameliorate estrogen deficiency-induced bone loss via the regulation of Wnt3a/β-catenin pathway.
基金supported by the National Natural Science Funds of China(Grant No.81703664)Science and Technology Funds of Lanzhou,China(Grant No.201603111)
文摘The traditional Chinese medicine of Radix Hedysari plays an important role in invigorating gas for ascending, benefiting blood for promoting production of fluid, and promoting circulation for removing obstruction in collaterals, which is consistent with the principle of treatment for osteoporosis. This study is designed to investigate the bioactive components on increasing peak bone mass (PBM) by exploring the spectrum-effect relationship between chromatography fingerprints and effect. Multiple indicators are selected to evaluate the pharmacological activity. In fingerprints, 21 common peaks are obtained, five of which are identified. Furthermore, gray relational analysis (GRA) is a quantitative method of gray system theory and is used to describe the correlation degree of common peaks and pharmacological activities with relational value. 21 components are then divided into three different regions, of which ononin and calycosin play an extremely significant role in increasing PBM. In addition, factor analysis and hierarchical cluster analysis (HCA) are used to screen the optimal producing area for Radix Hedysari. This provides a comprehensive and efficient method to improve the quality evaluation of Radix Hedysari, confirming the bioactive components for PBM-enhancement and further develop its medicinal value.
文摘The management of recurrent anterior gleno-humeral joint instability is challenging in the presence of boneloss.It is often seen in young athletic patients and dislocations related to epileptic seizures and may involve glenoid bone deficiency,humeral bone deficiency or combined bipolar lesions.It is critical to accurately identify and assess the amount and position of bone loss in order to select the most appropriate treatment and reduce the risk of recurrent instability after surgery.The current literature suggests that coracoid and iliac crest bone block transfers are reliable for treating glenoid defects.The treatment of humeral defects is more controversial,however,although good early results have been reported after arthroscopic Remplissage for small defects.Larger humeral defects may require complex reconstruction or partial resurfacing.There is currently very limited evidence to support treatment strategies when dealing with bipolar lesions.The aim of this review is to summarise the current evidence regarding the best imaging modalities and treatment strategies in managing this complex problem relating particularly to contact athletes and dislocations related to epileptic seizures.
文摘The number of revision total hip arthroplasties is expected to rise as the indications for arthroplasty will expand due to the aging population. The prevalence of extensive proximal femoral bone loss is expected to increase subsequently. The etiology of bone loss from the proximal femur after total hip arthroplasty is multifactorial. Stress shielding, massive osteolysis, extensive loosening and history of multiple surgeries consist the most common etiologies. Reconstruction of extensive bone loss of the proximal femur during a revision hip arthroplasty is a major challenge for even the most experienced orthopaedic surgeon. The amount of femoral bone loss and the bone quality of the remaining metaphyseal and diaphyseal bone dictate the selection of appropriate reconstructive option. These include the use of impaction allografting, distal press-fit fixation, allograft-prosthesis composites and tumor megaprostheses. This review article is a concise review of the current literature and provides an algorithmic approachfor reconstruction of different types of proximal femoral bone defects.
文摘AIM To study the clinical findings and characteristic features in sciatic notch dumbbell tumors(SNDTs).METHODS We retrospectively reviewed the clinical outcomes and characteristic features of consecutive cases of SNDTs(n = 8). RESULTS Buttock masses occurred in three patients with SNDT(37.5%). Severe buttock tenderness and pain at rest were observed in seven patients with SNDTs(87.5%). Remarkably, none of the patients with SNDTs experienced back pain. Mean tumor size was 8.4 ± 2.0 cm(range, 3.9 to 10.6 cm) and part of the tumor mass was detected in 2 patients in the sagittal view of lumbar magnetic resonance imaging(MRI).CONCLUSION The clinical information regarding to SNDTs is scarce. The authors consider that above mentioned characteristic findings may facilitate the suspicion of pelvic pathology and a search for SNDT by MRI or computed tomography should be considered in patients presenting with sciatica without evidence of spinal diseases.
基金Beijing Natural Science Foundation,Grant/Award Number:L222145CAMS Innovation Fund for Medical Sciences,Grant/Award Number:2019-I2M-5-038+2 种基金Clinical Medicine Plus X-Young Scholars Project,Peking Universitythe Fundamental Research Funds for the Central Universities,Grant/Award Number:PKU2023LCXQ017National Natural Science Foundation of China,Grant/Award Number:81700935。
文摘Background:The effect of platelet factor 4(PF4)on bone marrow mesenchymal stem cells(BMMSCs)and osteoporosis is poorly understood.Therefore,this study aimed to evaluate the effects of PF4-triggered bone destruction in mice and determine the underlying mechanism.Methods:First,in vitro cell proliferation and cell cycle of BMMSCs were assessed using a CCK8 assay and flow cytometry,respectively.Osteogenic differentiation was confirmed using staining and quantification of alkaline phosphatase and Alizarin Red S.Next,an osteoporotic mouse model was established by performing bilateral ovariectomy(OVX).Furthermore,the PF4 concentrations were obtained using enzymelinked immunosorbent assay.The bone microarchitecture of the femur was evaluated using microCT and histological analyses.Finally,the key regulators of osteogenesis and pathways were investigated using quantitative real-time polymerase chain reaction and Western blotting.Results:Human PF4 widely and moderately decreased the cell proliferation and osteogenic differentiation ability of BMMSCs.Furthermore,the levels of PF4 in the serum and bone marrow were generally increased,whereas bone microarchitecture deteriorated due to OVX.Moreover,in vivo mouse PF4 supplementation triggered bone deterioration of the femur.In addition,several key regulators of osteogenesis were downregulated,and the integrinα5-focal adhesion kinase-extracellular signalregulated kinase(ITGA5-FAK-ERK)pathway was inhibited due to PF4 supplementation.Conclusions:PF4 may be attributed to OVX-i nduced bone loss triggered by the suppression of bone formation in vivo and alleviate BMMSC osteogenic differentiation by inhibiting the ITGA5-FAK-ERK pathway.
基金the research committee of Malek-ashtar University of Technology(MUT)
文摘The kintic and activation energy of mass loss of two grades of melted TNT explosive, grade A and grade B, with freezing points of 80.57 and 78.15 ℃, respectively, were studied by isothermal and nonisothermal gravimetric methods. In isothermal method, the mass loss of samples in containers of glass and aluminum was followed in temperatures of 80, 90 and 100 ℃. The kinetic of the mass loss of the samples in the aluminum container was higher than the kinetic of it in the glass container that can be related to the effects of heat transfer and catalytic of aluminm metal. Also, the presence of impurities in grade B was due to increasing of kinetic of mass loss of it versus grade A. The non-isothermal curves were obtained in range of 30-330 ℃ at heating rates of 10,15 and 20 ℃·min^(-1).The TG/DTG data were used for determination of activation energy(E_a) of mass loss of TNT samples upon degradation by using Ozawa, Kissinger, Ozawa-Flynn-Wall(OFW) and Kissinger-Akahira-Sunose(KAS) methods as model free methods. The activation energies of grades of A and B of TNT was obtained 99-120 and 66-70 kJ mol^(-1)respectively. The lower values of activation energy of the degradation reaction of grade B confirm the effect of impurities in the kinetics of mass loss of this grade.
基金by the National Natural Science Foundation of China(Grant No.51991392)the National Natural Science Foundation of China(Grant No.51922104).
文摘Displacement-monitoring-based back analysis is a popular method for geomechanical parameter estimation.However,due to the delayed installation of multi-point extensometers,the monitoring curve is only a part of the overall one,leading to displacement loss.Besides,the monitoring and construction time on the monitoring curve is difficult to determine.In the literature,the final displacement was selected for the back analysis,which could induce unreliable results.In this paper,a displacement-based back analysis method to mitigate the influence of displacement loss is developed.A robust hybrid optimization algorithm is proposed as a substitute for time-consuming numerical simulation.It integrates the strengths of the nonlinear mapping and prediction capability of the support vector machine(SVM)algorithm,the global searching and optimization characteristics of the optimized particle swarm optimization(OPSO)algorithm,and the nonlinear numerical simulation capability of ABAQUS.To avoid being trapped in the local optimum and to improve the efficiency of optimization,the standard PSO algorithm is improved and is compared with other three algorithms(genetic algorithm(GA),simulated annealing(SA),and standard PSO).The results indicate the superiority of OPSO algorithm.Finally,the hybrid optimization algorithm is applied to an engineering project.The back-analyzed parameters are submitted to numerical analysis,and comparison between the calculated and monitoring displacement curve shows that this hybrid algorithm can offer a reasonable reference for geomechanical parameters estimation.
基金the National Natural Science Foundation of China(No.31772622)National Natural Science Foundation of China(No.32072748)Doctoral Fellowship from Henan Agricultural University(No.0501182)。
文摘Background:Escherichia coli(E.coli)infection in humans and animals usually comes with gut dysbiosis,which is potential culprit to skeletal health,it is still unclear to whether diet interfered gut microbiome changes can be a protective strategy to bone loss development.Here,the effects of resistant starch from raw potato starch(RPS),a type of prebiotic,on E.coli-induced bone loss and gut microbial composition in meat ducks were evaluated.Results:The results showed that dietary 12%RPS treatment improved bone quality,depressed bone resorption,and attenuated the pro-inflammatory reaction in both ileum and bone marrow.Meanwhile,the 12%RPS diet also increased the abundance of Firmicutes in E.coli-treated birds,along with higher production of short-chain fatty acids(SCFAs)especially propionate and butyrate.Whereas addition ofβ-acid,an inhibitor of bacterial SCFAs production,to the drinking water of ducks fed 12%RPS diet significantly decreased SCFAs level in cecum content and eliminated RPS-induced tibial mass improvement.Further,treatment with MI-2 to abrogate mucosa-associated lymphoid tissue lymphoma translocation protein 1(Malt1)activity replicated the protective role of dietary 12%RPS in E.coli-induced bone loss including reduced the inhibition on nuclear factorκB(NF-κB)inflammasome activation,decreased bone resorption,and improved bone quality,which were correlated with comparable and higher regulatory T cells(Treg)frequency in MI-2 and 12%RPS group,respectively.Conclusions:These findings suggested that the diet with 12%RPS could alleviate E.coli-induced bone loss in meat ducks by changing the gut microbial composition and promoting concomitant SCFAs production,and consequently inhibiting Malt1/NF-κB inflammasome activation and Treg cells expansion.
基金supported by the National Natural Science Foundation of China (10672152)the Science Foundation of China Academy of Engineering Physics (2009A0201009)the Innovation Fund of the Institute of Structural Mechanics,CAEP (09CXJ05)
文摘Earth penetration weapon(EPW) is applicable for attacking underground targets protected by reinforced concrete and rocks.With increasing impact velocity,the mass loss/abrasion of penetrator increases,which significantly decreases the penetration efficiency due to the change of nose shape.The abrasion may induce instability of the penetrator,and lead to failure of its structure.A common disadvantage,i.e.dependence on corresponding experimental results,exists in all the available formulae,which limits their ranges of application in estimating the mass loss of penetrator.In this paper,we conduct a parametric study on the mass loss of penetrator,and indicate that the mass loss of penetrator can be determined by seven variables,i.e.,the initial impact velocity,initial nose shape,melting heat,shank diameter of projectile and density and strength of target as well as the aggregate hardness of target.Further discussion on factors dominant in the mass abrasion of penetrator are given,which may be helpful for optimizing the target or the projectile for defensive or offensive objectives,respectively.
文摘With increasing aging population,osteoporosis has emerged as a public health problem worldwide.Epidemiological data reveal that the prevalence of osteoporosis in cold regions is high,and low temperatures may crucially affect bone mass.Recent studies have found that the transient receptor potential melastatin-8(TRPM8)channel,a cold-sensitive ion channel,can sense cold environment,and can be activated in cold environment.It may play an antagonistic role in low temperature-induced bone mass reduction.Mechanistically,this function may be ascribed to the activation of TRPM8 channel proteins in human bone marrow mesenchymal stem cells(hBM-MSCs),which causes osteoblast differentiation and mineralization in the bone.TRPM8 channel on the surface of brown adipocytes participates in the thermogenesis in brown adipose tissue(BAT)and the regulation of whole-body energy balance to maintain bone homeostasis.TRPM8 may be involved in bone remodeling throughout life.This paper reviews recent research on the possible antagonistic mechanism of TRPM8 in signaling pathways related to low temperature-induced bone mass loss and assesses the possibility of TRPM8 as a molecular target for the prevention and treatment of low temperature-induced osteoporosis in cold regions.
基金Supported by Jiangsu Elderly Health Research Project,No.LD2021010Jiangsu Elderly Health Research Project,Key Project of Elderly Health Research Project,No.LKZ2022010Open Project of National Key Professional Base for Standardized Training of Resident Physicians in Zhongda Hospital Affiliated to Southeast University,No.ZDZYJD-QK-2022-7.
文摘BACKGROUND The prevalence of osteoporosis and low bone mass is steadily rising each year.Low body weight is commonly linked to diminished bone mass and serves as a robust predictor of osteoporosis.Nonetheless,the connection between body mass index(BMI),bone mineral density,and lipid profiles among the elderly remains elusive.AIM To examine the association between BMI and bone mass,explore the correlation between lipid profiles and bone mass,and delve into the interplay between lipid metabolism and bone health.METHODS The study included 520 patients aged≥65 years(178 men and 342 women).Age,sex,weight,and height were recorded.Femoral neck bone mineral density and T scores were determined using a dual-energy X-ray absorptiometry scanner.Blood calcium(Ca),phosphorus(P),albumin(ALB),alkaline phosphatase(ALP),aspartate aminotransferase,alanine aminotransferase,triglyceride(TG),total cholesterol(TC),high-density lipoprotein(HDL)and low-density lipoprotein(LDL)levels were measured.Patients were classified by sex(male and female),age(65-79 years and≥80 years),and T score(normal bone mineral density,osteopenia and osteoporosis).RESULTS Age,sex,BMI,and ALP and TG levels were independent risk factors for osteoporosis.For the 65-79-and≥80-yearold groups,females presented lower T scores than males.Ca,P,ALB,ALP,TC,HDL and LDL levels were significantly different between men and women in the 65-79-year-old group.In addition,BMI and TG levels were significantly decreased in osteoporotic patients compared with patients with normal bone mass.TC levels declined in 65-to 79-year-old male and female osteoporosis patients.In the group of women aged≥80 years,osteoporotic patients showed significantly increased ALP levels.Furthermore,we found positive correlations between BMI and TG levels in the male and female patient groups.However,we found no significant differences in ALB,Ca,P,HDL and LDL levels in osteoporotic patients compared to patients with normal bone mass.CONCLUSION Osteoporotic patients showed significantly decreased BMI and TG levels compared with those with normal bone mass.BMI showed positive correlations with TG levels in male and female patients.These results indicate correlations between BMI and bone mass and between lipid profiles and bone mass.
文摘BACKGROUND Tranexamic acid(TXA)has been used as an anti-fibrinolytic drug for over half a century and has received much attention in recent decades.AIM To evaluate the efficacy of topical vs intravenous TXA in reducing blood loss and promoting wound healing in bone surgery.METHODS From the electronic resources,PubMed,Cochrane Library,Embase,ISI,and Scopus were used to perform a literature search over the last 10 years between 2010 and 2020.EndNote™X8 was used for managing the electronic resource.Searches were performed with mesh terms.The data were retracted blindly by two independent reviewers.Random effects were used to deal with potential heterogeneity and I2 showed heterogeneity.Chi-square(I2)tests were used to quantify the extent of heterogeneity(P<0.01 was considered statistically significant).The efficacy of topical TXA in reducing blood loss and promoting wound healing in bone surgery was compared with intravenous TXA and placebo.RESULTS According to the research design,1360 potentially important research abstracts and titles were discovered in our electronic searches,and 18 papers remained in agreement with our inclusion criteria.It was found that TXA reduced 277.51 mL of blood loss compared to placebo,and there was no significant difference between topical TXA and IV TXA in reducing blood loss in bone surgery.Our analyses also showed that TXA significantly reduced blood transfusion compared to placebo and there was no significant difference between topical TXA and IV TXA.CONCLUSION The use of both topical and intravenous TXA are equally effective in reducing blood loss in bone surgery,which might be beneficial for wound healing after surgery.
基金supported by the International Science&Technology Cooperation Program of China[No.2015DFR30940]the Science and Technology Research Project of Gansu Province[No.145RTSA012 and No.17JR5RA307]
文摘Objective To better understand the pathological causes of bone loss in a space environment, including microgravity, ionizing radiation, and ultradian rhythms. Methods Sprague Dawley(SD) rats were randomly divided into a baseline group, a control group, a hindlimb suspension group, a radiation group, a ultradian rhythms group and a combined-three-factor group. After four weeks of hindlimb suspension followed by X-ray exposure and/or ultradian rhythms, biomechanical properties, bone mineral density, histological analysis, microstructure parameters, and bone turnover markers were detected to evaluate bone loss in hindlimbs of rats. Results Simulated microgravity or combined-three factors treatment led to a significant decrease in the biomechanical properties of bones, reduction in bone mineral density, and deterioration of trabecular parameters. Ionizing radiation exposure also showed adverse impact while ultradian rhythms had no significant effect on these outcomes. Decrease in the concentration of the turnover markers bone alkaline phosphatase(b ALP), osteocalcin(OCN), and tartrate-resistant acid phosphatase-5 b(TRAP-5 b) in serum was in line with the changes in trabecular parameters. Conclusion Simulated microgravity is the main contributor of bone loss. Radiation also results in deleterious effects but ultradian rhythms has no significant effect. Combined-three factors treatment do not exacerbate bone loss when compared to simulated microgravity treatment alone.
基金supported by the National Outstanding Young Scientists Foundation of China(11225213)the Funds for Creative Research Groups of China(51321064)the National Natural Science Foundation of China(11172282 and 51378015)
文摘The mass loss and nose blunting of a projectile during high-speed deep penetration into concrete target may cause structural destruction and ballistic trajectory instability of the penetrator,obviously reducing the penetration efficiency of penetrator.Provided that the work of friction between projectile and target is totally transformed into the heat to melt penetrator material at its nose surface,an engineering model is established for the mass loss and nose-blunting of the ogive-nosed projectile.A dimensionless formula for the relative mass loss of projectile is obtained by introducing the dimensionless impact function I and geometry function N of the projectile.The critical value V c0of the initial striking velocity is formulated,and the mass loss of projectile tends to increase weakly nonlinearly with I/N when V0>V c0,whilst the mass loss is proportional to the initial kinetic energy of projectile when V0<V c0.The theoretical prediction of V c0is further confirmed to be very close to the experimental value of 1.0 km/s based on 11 sets of different penetration tests.Also the validity of the proposed expressions of massloss and nose-blunting coefficients of a projectile are verified by the tests.Therefore,a theoretical basis is for the empirical conclusions drawn in previous publications.Regarding the completely empirical determinations of the mass loss and nose-blunting coefficients given in previous papers,the present analysis reveals its physical characteristic and also guarantees its prediction accuracy.The engineering model established in the present paper forms the basis for further discussions on the structural stability and the terminal ballistic stability of ogive-nosed projectiles high-speed penetrating into concrete targets,which will respectively be elaborated in Part II and Part III of the present study.
基金supported by the National Institute of Dental and Craniofacial Research(NIDCR)the National Center for Research Resources(NCRR)of the National Institutes of Health(NIH)under award numbers R21DE023178,R01DE024796,and S10RR027553
文摘Hypoxia(low oxygen level) is an important feature during infections and affects the host defence mechanisms. The host has evolved specific responses to address hypoxia, which are strongly dependent on the activation of hypoxia-inducible factor 1(HIF-1).Hypoxia interferes degradation of HIF-1 alpha subunit(HIF-1α), leading to stabilisation of HIF-1α, heterodimerization with HIF-1 beta subunit(HIF-1β) and subsequent activation of HIF-1 pathway. Apical periodontitis(periapical lesion) is a consequence of endodontic infection and ultimately results in destruction of tooth-supporting tissue, including alveolar bone. Thus far, the role of HIF-1 in periapical lesions has not been systematically examined. In the present study, we determined the role of HIF-1 in a wellcharacterised mouse periapical lesion model using two HIF-1α-activating strategies, dimethyloxalylglycine(DMOG) and adenovirusinduced constitutively active HIF-1α(CA-HIF1 A). Both DMOG and CA-HIF1 A attenuated periapical inflammation and tissue destruction. The attenuation in vivo was associated with downregulation of nuclear factor-κappa B(NF-κB) and osteoclastic gene expressions. These two agents also suppressed NF-κB activation and subsequent production of proinflammatory cytokines by macrophages. Furthermore, activation of HIF-1α by DMOG specifically suppressed lipopolysaccharide-stimulated macrophage differentiation into M1 cells, increasing the ratio of M2 macrophages against M1 cells. Taken together, our data indicated that activation of HIF-1 plays a protective role in the development of apical periodontitis via downregulation of NF-κB, proinflammatory cytokines, M1 macrophages and osteoclastogenesis.
基金provided by the Doctor of Excellence Program from The First Hospital of Jilin University(No.JDYY-DEP-2022024)
文摘Background:Cachexia is a metabolic state with weight and muscle mass loss as its basic characteristics.This study aims to reveal the influ-ence of weight loss on the progression of cancer cachexia,and to determine its impact on the patient prognosis.Methods:A total of 2990 cancer patients were enrolled in this retrospective study.Demographic information,clinical materials,and follow-up data were collected for all patients.A receiver operating characteristic curve was used to determine threshold values for weight loss within the past six months(WL).Kaplan-Meier curves and Cox proportional hazard regression models were adopted for survival analyses.Results:After excluding ineligible patients,2480 patients were included in the analysis,705(28.4%)of whom were considered to be ca-chexic.A WL of 10%was determined to be the optimal threshold for diagnosing malnutrition according to the Patient-Generated Subjective Global Assessment.Notably,WL>10%was a predictor of survival outcomes only in the general population(HR=1.218,95%Cl=1.002-1.481,P=0.048),but not in the cachexic population,based on the multivariable Cox regression model.A larger proportion of cachexic pa-tients with WL>10%had a nutritional risk screening 2002 score≥3(25.7%vs 13.7%,P<0.001)and a modified Glasgow Prognosis Score=2(12.8%vs 7.8%,P=0.032).No significant difference was observed in the degree of decreased muscle strength or quality of life(P>0.05).Conclusions:Weight loss is a predictor of impaired survival in the general population,but not in the cachexic population.The present study shows that cachexic patients with severe weight loss had a higher risk of malnutrition,a worse systemic inflammation status,and more severe malnutrition,but that the weight loss itself was not associated with the prognosis of these patients or the progression of their cachexia.
基金granted by the National Key R&D Program of China (2021YFD21001005)National Natural Science Foundation of China (31972102,32101980)+1 种基金Special key project of Chongqing technology innovation and application development (cstc2021jscx-cylhX0014)Chongqing Technology Innovation and Application Development Special Project (cstc2021jscx-tpyzxX0014)。
文摘This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.
