Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of th...Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of the neighborhood search strategy,the robots could hardly obtain the most optimal global path.A global path planning algorithm,denoted as EDG*,is proposed by expanding nodes using a well-designed expanding disconnected graph operator(EDG)in this paper.Firstly,all obstacles are marked and their corners are located through the map pre-processing.Then,the EDG operator is designed to find points in non-obstruction areas to complete the rapid expansion of disconnected nodes.Finally,the EDG*heuristic iterative algorithm is proposed.It selects the candidate node through a specific valuation function and realizes the node expansion while avoiding collision with a minimum offset.Path planning experiments were conducted in a typical indoor environment and on the public dataset CSM.The result shows that the proposed EDG*reduced the planning time by more than 90%and total length of paths reduced by more than 4.6%.Compared to A*,Dijkstra and JPS,EDG*does not show an exponential explosion effect in map size.The EDG*showed better performance in terms of path smoothness,and collision avoidance.This shows that the EDG*algorithm proposed in this paper can improve the efficiency of path planning and enhance path quality.展开更多
BACKGROUND Endoscopic management is the first-line therapy for post-liver-transplant anas-tomotic strictures.Although the optimal duration of treatment with plastic stents has been reported to be 8-12 months,data on s...BACKGROUND Endoscopic management is the first-line therapy for post-liver-transplant anas-tomotic strictures.Although the optimal duration of treatment with plastic stents has been reported to be 8-12 months,data on safety and duration for metal stents in this setting is scarce.Due to limited access to endoscopic retrograde cholan-giopancreatography(ERCP)during the coronavirus disease 2019 pandemic in our centre,there was a change in practice towards increased usage and length-of-stay of the Kaffes biliary intraductal self-expanding stent in patients with suitable anatomy.This was mainly due to the theoretical benefit of Kaffes stents allowing for longer indwelling periods compared to the traditional plastic stents.METHODS Adult liver transplant recipients aged 18 years and above who underwent ERCP were retrospectively identified during a 10-year period through a database query.Unplanned admissions post-Kaffes stent insertion were identified manually through electronic and scanned medical records.The main outcome was the incidence of complications when stents were left indwelling for 3 months vs 6 months.Stent efficacy was calculated via rates of stricture recurrence between patients that had stenting courses for≤120 d or>120 d.RESULTS During the study period,a total of 66 ERCPs with Kaffes insertion were performed in 54 patients throughout their stenting course.In 33 ERCPs,the stent was removed or exchanged on a 3-month interval.No pancreatitis,perfor-ations or deaths occurred.Minor post-ERCP complications were similar between the 3-month(abdominal pain and intraductal migration)and 6-month(abdominal pain,septic shower and embedded stent)groups-6.1%vs 9.1%respectively,P=0.40.All strictures resolved at the end of the stenting course,but the stenting course was variable from 3 to 22 months.The recurrence rate for stenting courses lasting for up to 120 d was 71.4%and 21.4%for stenting courses of 121 d or over(P=0.03).There were 28 patients that were treated with a single ERCP with Kaffes,21 with removal after 120 d and 7 within 120 d.There was a significant improvement in stricture recurrence when the Kaffes was removed after 120 d when a single ERCP was used for the entire stenting course(71.0%vs 10.0%,P=0.01).CONCLUSION Utilising a single Kaffes intraductal fully-covered metal stent for at least 4 months is safe and efficacious for the management of post-transplant anastomotic strictures.展开更多
The hidden world of amyloid biology has suddenly snapped into atomic-level focus,revealing over 80 amyloid protein fibrils,both pathogenic and functional.Unlike globular proteins,amyloid proteins flatten and stack int...The hidden world of amyloid biology has suddenly snapped into atomic-level focus,revealing over 80 amyloid protein fibrils,both pathogenic and functional.Unlike globular proteins,amyloid proteins flatten and stack into unbranched fibrils.Stranger still,a single protein sequence can adopt wildly different two-dimensional conformations,yielding distinct fibril polymorphs.展开更多
On January 3,2023,China welcomed the first visit in the new year by a foreign head of state,Philippine President Ferdinand Marcos Jr.The visit was also the president’s first official state visit to a country outside ...On January 3,2023,China welcomed the first visit in the new year by a foreign head of state,Philippine President Ferdinand Marcos Jr.The visit was also the president’s first official state visit to a country outside ASEAN since he took office in June 2022,which demonstrated the great importance the two countries attach to their bilateral relations.The three-day visit was fruitful despite a tight schedule.展开更多
China and FAO assist Uganda to become self-sufficent in food production, and serve as the food basket of the region Eighty percent of Uganda’s economy depends on agriculture, according to the Uganda Bureau of Statist...China and FAO assist Uganda to become self-sufficent in food production, and serve as the food basket of the region Eighty percent of Uganda’s economy depends on agriculture, according to the Uganda Bureau of Statistics. For this reason, Frank Tumwebaze, Uganda’s minister of agriculture, animal industry and fisheries, said in an interview recently that since the majority of the country’s population is involved in agriculture.展开更多
Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,t...Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model tests.The testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge loading.The distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge loading.An approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.展开更多
As a key component in all-optical networks,all-optical switches play a role in constructing all-optical switching.Due to the absence of photoelectric conversion,all-optical networks can overcome the constraints of ele...As a key component in all-optical networks,all-optical switches play a role in constructing all-optical switching.Due to the absence of photoelectric conversion,all-optical networks can overcome the constraints of electronic bottlenecks,thereby improving communication speed and expanding their communication bandwidth.We study all-optical switches based on the interactions among three optical solitons.By analytically solving the coupled nonlinear Schr¨odinger equation,we obtain the three-soliton solution to the equation.We discuss the nonlinear dynamic characteristics of various optical solitons under different initial conditions.Meanwhile,we analyze the influence of relevant physical parameters on the realization of all-optical switching function during the process of three-soliton interactions.The relevant conclusions will be beneficial for expanding network bandwidth and reducing power consumption to meet the growing demand for bandwidth and traffic.展开更多
Mechanobiology is a rapidly growing field that has expanded significantly over the past 40 years.There have been great examples of mechanobiology research on the cardiovascular,musculoskeletal,and respiratory systems....Mechanobiology is a rapidly growing field that has expanded significantly over the past 40 years.There have been great examples of mechanobiology research on the cardiovascular,musculoskeletal,and respiratory systems.The field has evolved from the system level to the organ and tissue levels,and down to the cellular and molecular levels,benefiting from scientific progress and technological developments in molecular and cell biology,biomaterials,imaging techniques,and computational tools.Additionally,the interdisciplinary integration of mechanobiology with cell engineering,tissue engineering,and drug delivery has led to promising mechanomedicine applications in both therapeutics and diagnostics.Here,I will discuss two examples at the molecular and cellular levels:(1)mechanical regulation of epigenomics for cell reprogramming,and(2)engineering the mechanical properties of artificial antigen-presenting cells(APCs)for immune cell modulation and cancer therapy.Cell memory of its identity is determined by the epigenetic state of the cells.However,how cells control the epigenetic state and thus cell fate is not well understood,and how mechanical factors such as surface topography,cell morphology,mechanical properties of the extracellular matrix(ECM),and the mechanical deformation of cells regulate the epigenetic state is not clear.In an early study,we showed that biophysical cues,in the form of parallel microgrooves on the surface of cell-adhesive substrates,can replace the effects of small-molecule epigenetic modifiers and significantly improve reprogramming efficiency from fibroblasts to induced pluripotent stem cells.The mechanism relies on the mechanomodulation of the cells’epigenetic state through the activity of histone deacetylase and H3 methyltransferase.We also showed that microtopography promotes a mesenchymal-to-epithelial transition in adult fibroblasts.Nanofibrous scaffolds with aligned fiber orientation produce effects similar to those produced by microgrooves,suggesting that changes in cell morphology may be responsible for the modulation of the epigenetic state.The effects of micro/nanopatterned surfaces may be related to the reduction of intracellular tension and cell adhesion.Indeed,the reduction of actin cytoskeletal tension or cell adhesion at the early phase of reprogramming suppresses the expression of mesenchymal genes,promotes a more open chromatin structure,and significantly enhances the efficiency of induced neuronal(i N)conversion.Specifically,the reduction of intracellular tension or cell adhesion not only modulates global epigenetic marks but also decreases DNA methylation and heterochromatin marks while increasing euchromatin marks at the promoter of neuronal genes,thus enhancing the accessibility for gene activation.Finally,micro-and nano-topographic surfaces that reduce cell adhesion enhance i N reprogramming.These novel findings suggest that the actin cytoskeleton and focal adhesions play an important role in epigenetic regulation for cell fate determination,which may lead to biomaterialbased approaches for more effective cell reprogramming.In addition,matrix stiffness also regulates cell reprogramming,which acts as a biphasic regulator of the epigenetic state and fibroblast-to-neuron conversion efficiency,maximized at an intermediate stiffness of 20 k Pa.ATAC sequencing analysis shows the same trend of chromatin accessibility to neuronal genes at these stiffness levels.Concurrently,we observe peak levels of histone acetylation and histone acetyltransferase(HAT)activity in the nucleus on 20 k Pa matrices,and inhibiting HAT activity abolishes matrix stiffness effects.G-actin and cofilin,the co-transporters shuttling HAT into the nucleus,rise with decreasing matrix stiffness;however,reduced importin-9 on soft matrices limits nuclear transport.These two factors result in a biphasic regulation of HAT transport into the nucleus,which is directly demonstrated on matrices with dynamically tunable stiffness.Furthermore,we find that the regulation of the epigenetic state by the viscoelastic matrix is more pronounced on softermatrices.Cells on viscoelastic matrices exhibit larger nuclei,increased nuclear lamina ruffling,loosely organized chromatin,and faster chromatin dynamics compared to those on elastic matrices.These changes are accompanied by a global increase in euchromatic marks and a local increase in chromatin accessibility at the cis-regulatory elements associated with neuronal and pluripotent genes.Consequently,viscoelastic matrices enhance the efficiency of reprogramming fibroblasts into neurons and induced pluripotent stem cells,respectively.Together,our findings demonstrate the key roles of matrix viscoelasticity in regulating the epigenetic state and uncover a new mechanism of biophysical regulation of chromatin and cell reprogramming,with implications for designing smart materials to engineer cell fate.The viscoelasticity of biomaterials not only regulates cell adhesion and the epigenetic state but also modulates other ligand-receptor interactions such as T cell receptor activation.We developed a scalable microfluidic platform to fabricate synthetic viscoelastic activating cells(Syn VACs)with programmable mechanical and chemical properties.We demonstrated that the viscoelastic nature of Syn VACs significantly impacts T cell functionality.Compared to rigid or elastic microspheres,Syn VACs greatly enhance human T cell expansion with drastic CD8+T cell generation while suppressing regulatory T cell formation,resulting in enhanced tumor-killing capability.Notably,expanding chimeric antigen receptor(CAR)-T cells with Syn VACs achieves approximately 90%CAR transduction efficiency and leads to a six-fold increase in T memory stem cells.These engineered CAR-T cells exhibit superior efficacy in eliminating tumor cells,not only in a human lymphoma mouse model but also in a solid tumor xenograft mouse model of ovarian cancer.Additionally,Syn VAC-expanded CAR-T cells persist for longer periods in vivo to suppress tumor growth and recurrence.These findings underscore the crucial role of mechanical signals in T cell engineering and highlight the potential of the Syn VAC platform in CAR-T therapy and broad immunoengineering applications.These examples of mechanical regulation of cells not only unravel the underlying mechanisms of mechanotransduction in various cells,but also have tremendous potential to translate into therapeutic applications.展开更多
Point-of-care ultrasound(POCUS)is a core component of emergency medicine(EM)residency training used to guide medical decision making and to enhance procedural competence.[1-3]Many repetitions of POCUS exams are requir...Point-of-care ultrasound(POCUS)is a core component of emergency medicine(EM)residency training used to guide medical decision making and to enhance procedural competence.[1-3]Many repetitions of POCUS exams are required to achieve competency,and it is difficult to quantify a minimum needed to achieve mastery.[4,5]For EM residents whose career goals require greater depth of knowledge and skill in POCUS,educators can consider expanded training through a professional development track.展开更多
In recent years,the application of flexible electronic technology[1−3]combined with ultrasonic imaging[4]has blossomed,resulting in a shift in the application place of ultrasonic imaging technology from medical instit...In recent years,the application of flexible electronic technology[1−3]combined with ultrasonic imaging[4]has blossomed,resulting in a shift in the application place of ultrasonic imaging technology from medical institutions to households.The utilization of this application has expanded from the physician’s positioning and guidance to real-time patient monitoring[5],while the range of application scenarios continues to widen.The transformative changes have made possible through the development of flexible transducer arrays[6,7].Prof.Sheng Xu's team at the University of California San Diego has pioneered the development of various flexible transducer arrays based on island-bridge structures[8]and serpentine electrodes[9].These transducer arrays incorporate rigid 1−3 composite piezoelectric transducers on an island,featuring thin electrodes between the islands to provide mechanical flexibility,metallic electrodes of serpentine structure to provide stretchability of the device,and elastomer materials are used to encapsulate the overall structure,ensuring structural stability and impedance matching to the skin tissue[10].These flexible transducer arrays have found extensive applications in human blood pressure detection[11],cardiac imaging[12],blood flow doppler imaging[13],tissue modulus detection[14],and tissue deep hemoglobin detection[15].展开更多
To address the low conductivity and easy agglomeration of transition metal sulfide nanoparticles,FeCoS_(4) nanoparticles embedded in S-doped hollow carbon(FeCoS_(4)@S-HC)composites were successfully fabricated through...To address the low conductivity and easy agglomeration of transition metal sulfide nanoparticles,FeCoS_(4) nanoparticles embedded in S-doped hollow carbon(FeCoS_(4)@S-HC)composites were successfully fabricated through a combination of hydrothermal processes and sulfidation treatment.The unique bowlshaped FeCoS_(4)/S-HC composites exhibit excellent structural stability with a high specific surface area of 303.7 m^(2)·g^(-1) and a pore volume of 0.93 cm^(3)·g^(-1).When applied as anode material for lithium-ion batteries,the FeCoS_(4)@S-HC anode exhibits efficient lithium storage with high reversible specific capacity(970.2 mA·h·g^(-1) at 100 mA·g^(-1))and enhanced cycling stability(574 mA·h·g^(-1) at 0.2 A·g^(-1) after 350 cycles,a capacity retention of 84%).The excellent lithium storage is attributed to the fact that the bimetallic FeCoS_(4) nanoparticles with abundant active sites can accelerate the electrochemical reaction kinetics,and the bowl-shaped S-HC structure can provide a stable mechanical structure to suppress volume expansion.展开更多
In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollu...In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollution.At this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a problem-solver.Owing to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors nowadays.In this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF studies.Additionally,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive responses.Attained results show that PEC particles can be an alternative to expensive hollow spheres used in the previous works.Besides,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.展开更多
This study deals with base pressure management in a duct for various values of the Mach number(M),namely,Mach number corresponding to sonic and four supersonic conditions.In addition to the Mach number,the nozzle pres...This study deals with base pressure management in a duct for various values of the Mach number(M),namely,Mach number corresponding to sonic and four supersonic conditions.In addition to the Mach number,the nozzle pressure ratio(NPR),the area ratio,the rib dimension,and the duct length are influential parameters.The following specific values are examined at M=1,1.36,1.64,and 2,and NPRs between 1.5 and 10.The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct.When the level of expansion is varied,it is seen that the base pressure initially drops for overexpanded flows and increases for under-expanded flows.When ribs are present,the flow field in the duct and pressure inside the duct fluctuate as the base pressure rises.Under-expanded flows can achieve a base pressure value that is suitably high without experiencing excessive changes in the duct flow in terms of static pressure if a rib height around 10%of the duct height close to the nozzle exit is considered.Rectangular rib passive control does not negatively affect the duct’s flow field.展开更多
Several anatomical,demographic,clinical,electrocardiographic,procedural,and valve-related variables can be used to predict the probability of developing con-duction abnormalities after transcatheter aortic valve repla...Several anatomical,demographic,clinical,electrocardiographic,procedural,and valve-related variables can be used to predict the probability of developing con-duction abnormalities after transcatheter aortic valve replacement(TAVR)that necessitate permanent pacemaker(PPM)implantation.These variables include calcifications around the device landing zone and in the mitral annulus;pre-existing electrocardiographic abnormalities such as left and right bundle branch blocks(BBB),first-and second-degree atrioventricular blocks,as well as bifas-cicular and trifascicular blocks;male sex;diabetes mellitus(DM);hypertension;history of atrial fibrillation;renal failure;dementia;and use of self-expanding valves.The current study supports existing literature by demonstrating that type 2 DM and baseline right BBB are significant predictors of PPM implantation post-TAVR.Regardless of the side of the BBB,this study demonstrated,for the first time,a linear association between the incidence of PPM implantation post-TAVR and every 20 ms increase in baseline QRS duration(above 100 ms).After a 1-year follow-up,patients who received PPM post-TAVR had a higher rate of hospital-ization for heart failure and nonfatal myocardial infarction.展开更多
Alkaline water electrolysis(AWE)is the most mature technology for hydrogen production by water electrolysis.Alkaline water electrolyzer consists of multiple electrolysis cells,and a single cell consists of a diaphragm...Alkaline water electrolysis(AWE)is the most mature technology for hydrogen production by water electrolysis.Alkaline water electrolyzer consists of multiple electrolysis cells,and a single cell consists of a diaphragm,electrodes,bipolar plates and end plates,etc.The existing industrial bipolar plate channel is concave-convex structure,which is manufactured by complicated and high-cost mold punching.This structure still results in uneven electrolyte flow and low current density in the electrolytic cell,further increasing in energy consumption and cost of AWE.Thereby,in this article,the electrochemical and flow model is firstly constructed,based on the existing industrial concave and convex flow channel structure of bipolar plate,to study the current density,electrolyte flow and bubble distribution in the electrolysis cell.The reliability of the model was verified by comparison with experimental data in literature.Among which,the electrochemical current density affects the bubble yield,on the other hand,the generated bubbles cover the electrode surface,affecting the active specific surface area and ohmic resistance,which in turn affects the electrochemical reaction.The result indicates that the flow velocity near the bottom of the concave ball approaches zero,while the flow velocity on the convex ball surface is significantly higher.Additionally,vortices are observed within the flow channel structure,leading to an uneven distribution of electrolyte.Next,modelling is used to optimize the bipolar plate structure of AWE by simulating the electrochemistry and fluid flow performances of four kinds of structures,namely,concave and convex,rhombus,wedge and expanded mesh,in the bipolar plate of alkaline water electrolyzer.The results show that the expanded mesh channel structure has the largest current density of 3330 A/m^(2)and electrolyte flow velocity of 0.507 m/s in the electrolytic cell.Under the same current density,the electrolytic cell with the expanded mesh runner structure has the smallest potential and energy consumption.This work provides a useful guide for the comprehensive understanding and optimization of channel structures,and a theoretical basis for the design of large-scale electrolyzer.展开更多
Approximately 45 percent of malignant bone tumors are seen under the age of 16 and one of the important results of growth plate sacrification in patients with immature skeletons is limb inequality.Until the early 1990...Approximately 45 percent of malignant bone tumors are seen under the age of 16 and one of the important results of growth plate sacrification in patients with immature skeletons is limb inequality.Until the early 1990s,the treatment options for these patients were rotationplasty or amputation.Multimodal approaches that combine imaging,chemotherapy,and surgical techniques have enabled the development of limb-preserving methods with satisfactory results.In order to overcome inequality problems,expandable prostheses have been developed in the 1980s.Extendable endoprosthesis replacements have been improved over the years and are now an established and safe alternative.Noninvasive prostheses appear to be advantageous compared to minimally invasive expandable prostheses that require multiple surgical procedures,but the complication rate remains high.Therefore,although expandable prostheses are not the definitive answer to the treatment of bone sarcomas in skeletally immature children,they are still a suitable interim choice until full adulthood is achieved.Due to reported high complication rates,the procedures require significant experience and are recommended for use only in specialized cancer centers.展开更多
NDRC Brings Forward Investment Plans China will bring forward part of the investment plans originally set for 2025 to this year while studying the effects in the hopes of expanding the extent to which local government...NDRC Brings Forward Investment Plans China will bring forward part of the investment plans originally set for 2025 to this year while studying the effects in the hopes of expanding the extent to which local government special bonds can be used,as part of the country’s stepped-up efforts to spur on investment and achieve steady economic growth,officials said.展开更多
Since the second half of 2023,China have initiated mutual visa-free policies for outbound tourism with such countries as Singapore,Malaysia,Thailand and Georgia.With the continuous advancement of these visa-free polic...Since the second half of 2023,China have initiated mutual visa-free policies for outbound tourism with such countries as Singapore,Malaysia,Thailand and Georgia.With the continuous advancement of these visa-free policies,the list of outbound tourist destination countries is constantly expanding.During this summer vacation in particular,outbound tourism is gaining popularity.展开更多
Introduction: As new vaccines become available, countries must assess the relevance to introduce them into their vaccination schedules. Malawi has recently introduced several new vaccines and plans to introduce more. ...Introduction: As new vaccines become available, countries must assess the relevance to introduce them into their vaccination schedules. Malawi has recently introduced several new vaccines and plans to introduce more. This study was conducted to identify key factors that need to be considered when deciding to introduce a new vaccine and current challenges faced by low and middle income countries using Malawi as an example. Methodology: The study employed a desk review approach, examining published literature from various sources such as PubMed, Medline, and Google Scholar. Policy documents from organizations like the World Health Organization, GAVI the Alliance, and the Ministry of Health for Malawi were also included. A total of 99 articles and documents on new vaccine introduction, challenges of immunization, policy documents in immunization and health systems strengthening were included. The review focused on addressing five key areas critical to new vaccine introduction namely: the need for a vaccine, availability of the vaccine, safety and effectiveness of the vaccine, demand for the vaccine, and the prudent use of public or private funds. Results: Malawi considered the burden of cervical cancer and the significance of malaria in the country when introducing the HPV and malaria vaccines. The country opted for vaccines that can be handled by the cold chain capacity and available human resources. Despite that malaria vaccine and Typhoid Conjugate Vaccine trials were done in country, there are limited vaccine safety and efficacy trials conducted in Malawi, leading to a reliance on WHO-prequalified vaccines. Demand for newly introduced vaccines varied, with high demand for Oral Cholera Vaccine during a cholera outbreak, while demand for COVID-19 vaccines decreased over time. Although cost-effectiveness studies were limited in the country, 2 studies indicated that Typhoid Conjugate Vaccine and malaria vaccine would be cost effective. All these have been implemented despite having challenges like lack of accurate surveillance data, inadequate cold chain capacity, limited safety and efficacy vaccine clinical trials, political influence, and limited funding. Conclusion: Despite several challenges Malawi set a good example of the careful considerations required before introducing a new vaccine. The process involves data review, priority setting, precise planning, and consultation with stakeholders. Low-income countries should invest in vaccine safety, efficacy, and cost-effectiveness trials.展开更多
Objective: By observing the treatment and nursing care of a patient with Grade IV capsular contracture following breast cancer expander implantation and subsequent Stage II reconstruction, we aim to analyze the reason...Objective: By observing the treatment and nursing care of a patient with Grade IV capsular contracture following breast cancer expander implantation and subsequent Stage II reconstruction, we aim to analyze the reasons for the formation of capsular contracture after Stage I expander implantation and prevent its recurrence following Stage II reconstruction. Methods: In May 2020, the patient noticed an increase in the size of a breast mass. In August, she underwent AC-THP neoadjuvant chemotherapy, followed by a “right breast-conserving nipple-areolar subglandular excision + right axillary lymph node dissection + expander implantation” surgery in November 2020. Radiation therapy began in January 2021. During radiation therapy, the patient experienced severe breast hardening, distortion, tenderness, and was diagnosed with Grade IV capsular contracture. To relieve the capsular contracture, the patient underwent a “contracted capsule incision and release procedure + removal of the right breast expander + right breast implantation” surgery in July 2021. Postoperatively, measures were taken to prevent incision infection, emphasizing aseptic techniques, ensuring smooth negative pressure drainage, reducing skin flap tension, monitoring skin flap blood supply, actively preventing subcutaneous effusion and hematoma, and applying appropriate compression dressings. Results: The patient was discharged after the removal of the drainage tube. During the postoperative follow-up at 3 and 6 months, there was no recurrence of capsular contracture, and the breast appeared full, upright, and relatively soft. There were no complications such as hematoma, infection, breast implant rupture, breast sagging, or displacement. The patient had a good outcome without additional financial or surgical burdens. Conclusion: The occurrence of Grade IV capsular contracture in the patient is generally related to infection after Stage I expander implantation, improper compression dressing, excessive saline injection causing content infiltration, and radiation therapy. Therefore, it is recommended to enhance the intraoperative and postoperative prophylactic use of antibiotics after Stage I expander implantation. Intermittent saline injection after surgery, with the amount of saline gradually increasing rather than filling all at once, is advisable. This helps the breast tissue gradually adapt to expansion, reducing the risk of capsular contracture. Postoperatively, patients should be instructed to wear pressure garments and breast elastic bandages while intensifying breast monitoring during radiation therapy and increasing postoperative follow-up.展开更多
基金Supported by National Key Research and Development Program of China(Grant No.2022YFB4700402).
文摘Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of the neighborhood search strategy,the robots could hardly obtain the most optimal global path.A global path planning algorithm,denoted as EDG*,is proposed by expanding nodes using a well-designed expanding disconnected graph operator(EDG)in this paper.Firstly,all obstacles are marked and their corners are located through the map pre-processing.Then,the EDG operator is designed to find points in non-obstruction areas to complete the rapid expansion of disconnected nodes.Finally,the EDG*heuristic iterative algorithm is proposed.It selects the candidate node through a specific valuation function and realizes the node expansion while avoiding collision with a minimum offset.Path planning experiments were conducted in a typical indoor environment and on the public dataset CSM.The result shows that the proposed EDG*reduced the planning time by more than 90%and total length of paths reduced by more than 4.6%.Compared to A*,Dijkstra and JPS,EDG*does not show an exponential explosion effect in map size.The EDG*showed better performance in terms of path smoothness,and collision avoidance.This shows that the EDG*algorithm proposed in this paper can improve the efficiency of path planning and enhance path quality.
文摘BACKGROUND Endoscopic management is the first-line therapy for post-liver-transplant anas-tomotic strictures.Although the optimal duration of treatment with plastic stents has been reported to be 8-12 months,data on safety and duration for metal stents in this setting is scarce.Due to limited access to endoscopic retrograde cholan-giopancreatography(ERCP)during the coronavirus disease 2019 pandemic in our centre,there was a change in practice towards increased usage and length-of-stay of the Kaffes biliary intraductal self-expanding stent in patients with suitable anatomy.This was mainly due to the theoretical benefit of Kaffes stents allowing for longer indwelling periods compared to the traditional plastic stents.METHODS Adult liver transplant recipients aged 18 years and above who underwent ERCP were retrospectively identified during a 10-year period through a database query.Unplanned admissions post-Kaffes stent insertion were identified manually through electronic and scanned medical records.The main outcome was the incidence of complications when stents were left indwelling for 3 months vs 6 months.Stent efficacy was calculated via rates of stricture recurrence between patients that had stenting courses for≤120 d or>120 d.RESULTS During the study period,a total of 66 ERCPs with Kaffes insertion were performed in 54 patients throughout their stenting course.In 33 ERCPs,the stent was removed or exchanged on a 3-month interval.No pancreatitis,perfor-ations or deaths occurred.Minor post-ERCP complications were similar between the 3-month(abdominal pain and intraductal migration)and 6-month(abdominal pain,septic shower and embedded stent)groups-6.1%vs 9.1%respectively,P=0.40.All strictures resolved at the end of the stenting course,but the stenting course was variable from 3 to 22 months.The recurrence rate for stenting courses lasting for up to 120 d was 71.4%and 21.4%for stenting courses of 121 d or over(P=0.03).There were 28 patients that were treated with a single ERCP with Kaffes,21 with removal after 120 d and 7 within 120 d.There was a significant improvement in stricture recurrence when the Kaffes was removed after 120 d when a single ERCP was used for the entire stenting course(71.0%vs 10.0%,P=0.01).CONCLUSION Utilising a single Kaffes intraductal fully-covered metal stent for at least 4 months is safe and efficacious for the management of post-transplant anastomotic strictures.
文摘The hidden world of amyloid biology has suddenly snapped into atomic-level focus,revealing over 80 amyloid protein fibrils,both pathogenic and functional.Unlike globular proteins,amyloid proteins flatten and stack into unbranched fibrils.Stranger still,a single protein sequence can adopt wildly different two-dimensional conformations,yielding distinct fibril polymorphs.
文摘On January 3,2023,China welcomed the first visit in the new year by a foreign head of state,Philippine President Ferdinand Marcos Jr.The visit was also the president’s first official state visit to a country outside ASEAN since he took office in June 2022,which demonstrated the great importance the two countries attach to their bilateral relations.The three-day visit was fruitful despite a tight schedule.
文摘China and FAO assist Uganda to become self-sufficent in food production, and serve as the food basket of the region Eighty percent of Uganda’s economy depends on agriculture, according to the Uganda Bureau of Statistics. For this reason, Frank Tumwebaze, Uganda’s minister of agriculture, animal industry and fisheries, said in an interview recently that since the majority of the country’s population is involved in agriculture.
基金funding support from National Natural Science Foundation of China(Grant No.52179109)Jiangsu Provincial Natural Science Foundation(Grant No.BK20230967)Open Research Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University(Grant No.KF2022-02).
文摘Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model tests.The testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge loading.The distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge loading.An approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.
基金supported by the Scientific Research Foundation of Weifang University of Science and Technology(Grant Nos.KJRC2022002 and KJRC2023035)。
文摘As a key component in all-optical networks,all-optical switches play a role in constructing all-optical switching.Due to the absence of photoelectric conversion,all-optical networks can overcome the constraints of electronic bottlenecks,thereby improving communication speed and expanding their communication bandwidth.We study all-optical switches based on the interactions among three optical solitons.By analytically solving the coupled nonlinear Schr¨odinger equation,we obtain the three-soliton solution to the equation.We discuss the nonlinear dynamic characteristics of various optical solitons under different initial conditions.Meanwhile,we analyze the influence of relevant physical parameters on the realization of all-optical switching function during the process of three-soliton interactions.The relevant conclusions will be beneficial for expanding network bandwidth and reducing power consumption to meet the growing demand for bandwidth and traffic.
文摘Mechanobiology is a rapidly growing field that has expanded significantly over the past 40 years.There have been great examples of mechanobiology research on the cardiovascular,musculoskeletal,and respiratory systems.The field has evolved from the system level to the organ and tissue levels,and down to the cellular and molecular levels,benefiting from scientific progress and technological developments in molecular and cell biology,biomaterials,imaging techniques,and computational tools.Additionally,the interdisciplinary integration of mechanobiology with cell engineering,tissue engineering,and drug delivery has led to promising mechanomedicine applications in both therapeutics and diagnostics.Here,I will discuss two examples at the molecular and cellular levels:(1)mechanical regulation of epigenomics for cell reprogramming,and(2)engineering the mechanical properties of artificial antigen-presenting cells(APCs)for immune cell modulation and cancer therapy.Cell memory of its identity is determined by the epigenetic state of the cells.However,how cells control the epigenetic state and thus cell fate is not well understood,and how mechanical factors such as surface topography,cell morphology,mechanical properties of the extracellular matrix(ECM),and the mechanical deformation of cells regulate the epigenetic state is not clear.In an early study,we showed that biophysical cues,in the form of parallel microgrooves on the surface of cell-adhesive substrates,can replace the effects of small-molecule epigenetic modifiers and significantly improve reprogramming efficiency from fibroblasts to induced pluripotent stem cells.The mechanism relies on the mechanomodulation of the cells’epigenetic state through the activity of histone deacetylase and H3 methyltransferase.We also showed that microtopography promotes a mesenchymal-to-epithelial transition in adult fibroblasts.Nanofibrous scaffolds with aligned fiber orientation produce effects similar to those produced by microgrooves,suggesting that changes in cell morphology may be responsible for the modulation of the epigenetic state.The effects of micro/nanopatterned surfaces may be related to the reduction of intracellular tension and cell adhesion.Indeed,the reduction of actin cytoskeletal tension or cell adhesion at the early phase of reprogramming suppresses the expression of mesenchymal genes,promotes a more open chromatin structure,and significantly enhances the efficiency of induced neuronal(i N)conversion.Specifically,the reduction of intracellular tension or cell adhesion not only modulates global epigenetic marks but also decreases DNA methylation and heterochromatin marks while increasing euchromatin marks at the promoter of neuronal genes,thus enhancing the accessibility for gene activation.Finally,micro-and nano-topographic surfaces that reduce cell adhesion enhance i N reprogramming.These novel findings suggest that the actin cytoskeleton and focal adhesions play an important role in epigenetic regulation for cell fate determination,which may lead to biomaterialbased approaches for more effective cell reprogramming.In addition,matrix stiffness also regulates cell reprogramming,which acts as a biphasic regulator of the epigenetic state and fibroblast-to-neuron conversion efficiency,maximized at an intermediate stiffness of 20 k Pa.ATAC sequencing analysis shows the same trend of chromatin accessibility to neuronal genes at these stiffness levels.Concurrently,we observe peak levels of histone acetylation and histone acetyltransferase(HAT)activity in the nucleus on 20 k Pa matrices,and inhibiting HAT activity abolishes matrix stiffness effects.G-actin and cofilin,the co-transporters shuttling HAT into the nucleus,rise with decreasing matrix stiffness;however,reduced importin-9 on soft matrices limits nuclear transport.These two factors result in a biphasic regulation of HAT transport into the nucleus,which is directly demonstrated on matrices with dynamically tunable stiffness.Furthermore,we find that the regulation of the epigenetic state by the viscoelastic matrix is more pronounced on softermatrices.Cells on viscoelastic matrices exhibit larger nuclei,increased nuclear lamina ruffling,loosely organized chromatin,and faster chromatin dynamics compared to those on elastic matrices.These changes are accompanied by a global increase in euchromatic marks and a local increase in chromatin accessibility at the cis-regulatory elements associated with neuronal and pluripotent genes.Consequently,viscoelastic matrices enhance the efficiency of reprogramming fibroblasts into neurons and induced pluripotent stem cells,respectively.Together,our findings demonstrate the key roles of matrix viscoelasticity in regulating the epigenetic state and uncover a new mechanism of biophysical regulation of chromatin and cell reprogramming,with implications for designing smart materials to engineer cell fate.The viscoelasticity of biomaterials not only regulates cell adhesion and the epigenetic state but also modulates other ligand-receptor interactions such as T cell receptor activation.We developed a scalable microfluidic platform to fabricate synthetic viscoelastic activating cells(Syn VACs)with programmable mechanical and chemical properties.We demonstrated that the viscoelastic nature of Syn VACs significantly impacts T cell functionality.Compared to rigid or elastic microspheres,Syn VACs greatly enhance human T cell expansion with drastic CD8+T cell generation while suppressing regulatory T cell formation,resulting in enhanced tumor-killing capability.Notably,expanding chimeric antigen receptor(CAR)-T cells with Syn VACs achieves approximately 90%CAR transduction efficiency and leads to a six-fold increase in T memory stem cells.These engineered CAR-T cells exhibit superior efficacy in eliminating tumor cells,not only in a human lymphoma mouse model but also in a solid tumor xenograft mouse model of ovarian cancer.Additionally,Syn VAC-expanded CAR-T cells persist for longer periods in vivo to suppress tumor growth and recurrence.These findings underscore the crucial role of mechanical signals in T cell engineering and highlight the potential of the Syn VAC platform in CAR-T therapy and broad immunoengineering applications.These examples of mechanical regulation of cells not only unravel the underlying mechanisms of mechanotransduction in various cells,but also have tremendous potential to translate into therapeutic applications.
文摘Point-of-care ultrasound(POCUS)is a core component of emergency medicine(EM)residency training used to guide medical decision making and to enhance procedural competence.[1-3]Many repetitions of POCUS exams are required to achieve competency,and it is difficult to quantify a minimum needed to achieve mastery.[4,5]For EM residents whose career goals require greater depth of knowledge and skill in POCUS,educators can consider expanded training through a professional development track.
文摘In recent years,the application of flexible electronic technology[1−3]combined with ultrasonic imaging[4]has blossomed,resulting in a shift in the application place of ultrasonic imaging technology from medical institutions to households.The utilization of this application has expanded from the physician’s positioning and guidance to real-time patient monitoring[5],while the range of application scenarios continues to widen.The transformative changes have made possible through the development of flexible transducer arrays[6,7].Prof.Sheng Xu's team at the University of California San Diego has pioneered the development of various flexible transducer arrays based on island-bridge structures[8]and serpentine electrodes[9].These transducer arrays incorporate rigid 1−3 composite piezoelectric transducers on an island,featuring thin electrodes between the islands to provide mechanical flexibility,metallic electrodes of serpentine structure to provide stretchability of the device,and elastomer materials are used to encapsulate the overall structure,ensuring structural stability and impedance matching to the skin tissue[10].These flexible transducer arrays have found extensive applications in human blood pressure detection[11],cardiac imaging[12],blood flow doppler imaging[13],tissue modulus detection[14],and tissue deep hemoglobin detection[15].
基金financially supported by the National Natural Science Foundation of China(22379056,52102260)the Project funded by China Postdoctoral Science Foundation(2022M711545)the Carbon Peak and Carbon Neutrality Project(Breakthrough for Industry Prospect and Key Technologies)of Zhenjiang City(CG2023003)。
文摘To address the low conductivity and easy agglomeration of transition metal sulfide nanoparticles,FeCoS_(4) nanoparticles embedded in S-doped hollow carbon(FeCoS_(4)@S-HC)composites were successfully fabricated through a combination of hydrothermal processes and sulfidation treatment.The unique bowlshaped FeCoS_(4)/S-HC composites exhibit excellent structural stability with a high specific surface area of 303.7 m^(2)·g^(-1) and a pore volume of 0.93 cm^(3)·g^(-1).When applied as anode material for lithium-ion batteries,the FeCoS_(4)@S-HC anode exhibits efficient lithium storage with high reversible specific capacity(970.2 mA·h·g^(-1) at 100 mA·g^(-1))and enhanced cycling stability(574 mA·h·g^(-1) at 0.2 A·g^(-1) after 350 cycles,a capacity retention of 84%).The excellent lithium storage is attributed to the fact that the bimetallic FeCoS_(4) nanoparticles with abundant active sites can accelerate the electrochemical reaction kinetics,and the bowl-shaped S-HC structure can provide a stable mechanical structure to suppress volume expansion.
文摘In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollution.At this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a problem-solver.Owing to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors nowadays.In this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF studies.Additionally,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive responses.Attained results show that PEC particles can be an alternative to expensive hollow spheres used in the previous works.Besides,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.
文摘This study deals with base pressure management in a duct for various values of the Mach number(M),namely,Mach number corresponding to sonic and four supersonic conditions.In addition to the Mach number,the nozzle pressure ratio(NPR),the area ratio,the rib dimension,and the duct length are influential parameters.The following specific values are examined at M=1,1.36,1.64,and 2,and NPRs between 1.5 and 10.The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct.When the level of expansion is varied,it is seen that the base pressure initially drops for overexpanded flows and increases for under-expanded flows.When ribs are present,the flow field in the duct and pressure inside the duct fluctuate as the base pressure rises.Under-expanded flows can achieve a base pressure value that is suitably high without experiencing excessive changes in the duct flow in terms of static pressure if a rib height around 10%of the duct height close to the nozzle exit is considered.Rectangular rib passive control does not negatively affect the duct’s flow field.
文摘Several anatomical,demographic,clinical,electrocardiographic,procedural,and valve-related variables can be used to predict the probability of developing con-duction abnormalities after transcatheter aortic valve replacement(TAVR)that necessitate permanent pacemaker(PPM)implantation.These variables include calcifications around the device landing zone and in the mitral annulus;pre-existing electrocardiographic abnormalities such as left and right bundle branch blocks(BBB),first-and second-degree atrioventricular blocks,as well as bifas-cicular and trifascicular blocks;male sex;diabetes mellitus(DM);hypertension;history of atrial fibrillation;renal failure;dementia;and use of self-expanding valves.The current study supports existing literature by demonstrating that type 2 DM and baseline right BBB are significant predictors of PPM implantation post-TAVR.Regardless of the side of the BBB,this study demonstrated,for the first time,a linear association between the incidence of PPM implantation post-TAVR and every 20 ms increase in baseline QRS duration(above 100 ms).After a 1-year follow-up,patients who received PPM post-TAVR had a higher rate of hospital-ization for heart failure and nonfatal myocardial infarction.
基金financially supported by the National Natural Science Foundation of China(No.52074130)the Engineering Research Center of Resource Utilization of Carbon-containing Waste with Carbon Neutrality,Ministry of Education。
文摘Alkaline water electrolysis(AWE)is the most mature technology for hydrogen production by water electrolysis.Alkaline water electrolyzer consists of multiple electrolysis cells,and a single cell consists of a diaphragm,electrodes,bipolar plates and end plates,etc.The existing industrial bipolar plate channel is concave-convex structure,which is manufactured by complicated and high-cost mold punching.This structure still results in uneven electrolyte flow and low current density in the electrolytic cell,further increasing in energy consumption and cost of AWE.Thereby,in this article,the electrochemical and flow model is firstly constructed,based on the existing industrial concave and convex flow channel structure of bipolar plate,to study the current density,electrolyte flow and bubble distribution in the electrolysis cell.The reliability of the model was verified by comparison with experimental data in literature.Among which,the electrochemical current density affects the bubble yield,on the other hand,the generated bubbles cover the electrode surface,affecting the active specific surface area and ohmic resistance,which in turn affects the electrochemical reaction.The result indicates that the flow velocity near the bottom of the concave ball approaches zero,while the flow velocity on the convex ball surface is significantly higher.Additionally,vortices are observed within the flow channel structure,leading to an uneven distribution of electrolyte.Next,modelling is used to optimize the bipolar plate structure of AWE by simulating the electrochemistry and fluid flow performances of four kinds of structures,namely,concave and convex,rhombus,wedge and expanded mesh,in the bipolar plate of alkaline water electrolyzer.The results show that the expanded mesh channel structure has the largest current density of 3330 A/m^(2)and electrolyte flow velocity of 0.507 m/s in the electrolytic cell.Under the same current density,the electrolytic cell with the expanded mesh runner structure has the smallest potential and energy consumption.This work provides a useful guide for the comprehensive understanding and optimization of channel structures,and a theoretical basis for the design of large-scale electrolyzer.
文摘Approximately 45 percent of malignant bone tumors are seen under the age of 16 and one of the important results of growth plate sacrification in patients with immature skeletons is limb inequality.Until the early 1990s,the treatment options for these patients were rotationplasty or amputation.Multimodal approaches that combine imaging,chemotherapy,and surgical techniques have enabled the development of limb-preserving methods with satisfactory results.In order to overcome inequality problems,expandable prostheses have been developed in the 1980s.Extendable endoprosthesis replacements have been improved over the years and are now an established and safe alternative.Noninvasive prostheses appear to be advantageous compared to minimally invasive expandable prostheses that require multiple surgical procedures,but the complication rate remains high.Therefore,although expandable prostheses are not the definitive answer to the treatment of bone sarcomas in skeletally immature children,they are still a suitable interim choice until full adulthood is achieved.Due to reported high complication rates,the procedures require significant experience and are recommended for use only in specialized cancer centers.
文摘NDRC Brings Forward Investment Plans China will bring forward part of the investment plans originally set for 2025 to this year while studying the effects in the hopes of expanding the extent to which local government special bonds can be used,as part of the country’s stepped-up efforts to spur on investment and achieve steady economic growth,officials said.
文摘Since the second half of 2023,China have initiated mutual visa-free policies for outbound tourism with such countries as Singapore,Malaysia,Thailand and Georgia.With the continuous advancement of these visa-free policies,the list of outbound tourist destination countries is constantly expanding.During this summer vacation in particular,outbound tourism is gaining popularity.
文摘Introduction: As new vaccines become available, countries must assess the relevance to introduce them into their vaccination schedules. Malawi has recently introduced several new vaccines and plans to introduce more. This study was conducted to identify key factors that need to be considered when deciding to introduce a new vaccine and current challenges faced by low and middle income countries using Malawi as an example. Methodology: The study employed a desk review approach, examining published literature from various sources such as PubMed, Medline, and Google Scholar. Policy documents from organizations like the World Health Organization, GAVI the Alliance, and the Ministry of Health for Malawi were also included. A total of 99 articles and documents on new vaccine introduction, challenges of immunization, policy documents in immunization and health systems strengthening were included. The review focused on addressing five key areas critical to new vaccine introduction namely: the need for a vaccine, availability of the vaccine, safety and effectiveness of the vaccine, demand for the vaccine, and the prudent use of public or private funds. Results: Malawi considered the burden of cervical cancer and the significance of malaria in the country when introducing the HPV and malaria vaccines. The country opted for vaccines that can be handled by the cold chain capacity and available human resources. Despite that malaria vaccine and Typhoid Conjugate Vaccine trials were done in country, there are limited vaccine safety and efficacy trials conducted in Malawi, leading to a reliance on WHO-prequalified vaccines. Demand for newly introduced vaccines varied, with high demand for Oral Cholera Vaccine during a cholera outbreak, while demand for COVID-19 vaccines decreased over time. Although cost-effectiveness studies were limited in the country, 2 studies indicated that Typhoid Conjugate Vaccine and malaria vaccine would be cost effective. All these have been implemented despite having challenges like lack of accurate surveillance data, inadequate cold chain capacity, limited safety and efficacy vaccine clinical trials, political influence, and limited funding. Conclusion: Despite several challenges Malawi set a good example of the careful considerations required before introducing a new vaccine. The process involves data review, priority setting, precise planning, and consultation with stakeholders. Low-income countries should invest in vaccine safety, efficacy, and cost-effectiveness trials.
文摘Objective: By observing the treatment and nursing care of a patient with Grade IV capsular contracture following breast cancer expander implantation and subsequent Stage II reconstruction, we aim to analyze the reasons for the formation of capsular contracture after Stage I expander implantation and prevent its recurrence following Stage II reconstruction. Methods: In May 2020, the patient noticed an increase in the size of a breast mass. In August, she underwent AC-THP neoadjuvant chemotherapy, followed by a “right breast-conserving nipple-areolar subglandular excision + right axillary lymph node dissection + expander implantation” surgery in November 2020. Radiation therapy began in January 2021. During radiation therapy, the patient experienced severe breast hardening, distortion, tenderness, and was diagnosed with Grade IV capsular contracture. To relieve the capsular contracture, the patient underwent a “contracted capsule incision and release procedure + removal of the right breast expander + right breast implantation” surgery in July 2021. Postoperatively, measures were taken to prevent incision infection, emphasizing aseptic techniques, ensuring smooth negative pressure drainage, reducing skin flap tension, monitoring skin flap blood supply, actively preventing subcutaneous effusion and hematoma, and applying appropriate compression dressings. Results: The patient was discharged after the removal of the drainage tube. During the postoperative follow-up at 3 and 6 months, there was no recurrence of capsular contracture, and the breast appeared full, upright, and relatively soft. There were no complications such as hematoma, infection, breast implant rupture, breast sagging, or displacement. The patient had a good outcome without additional financial or surgical burdens. Conclusion: The occurrence of Grade IV capsular contracture in the patient is generally related to infection after Stage I expander implantation, improper compression dressing, excessive saline injection causing content infiltration, and radiation therapy. Therefore, it is recommended to enhance the intraoperative and postoperative prophylactic use of antibiotics after Stage I expander implantation. Intermittent saline injection after surgery, with the amount of saline gradually increasing rather than filling all at once, is advisable. This helps the breast tissue gradually adapt to expansion, reducing the risk of capsular contracture. Postoperatively, patients should be instructed to wear pressure garments and breast elastic bandages while intensifying breast monitoring during radiation therapy and increasing postoperative follow-up.
