Reaction kinetics determination based on microfluidic technology

Microfluidic technology has been successfully applied to determine the reaction kinetics relying on its great characteristics including narrow residence time distribution,fast mixing,high mass and heat transfer rates and very low consumption of materials.In this review,the recent progresses about the reaction kinetics measured in microreactors are comprehensively organized,and the kinetic modeling thoughts,determination methods and essential kinetic regularities contained in these studies are summarized according to the reaction types involving nitration,oxidation,hydrogenation,photochemical reaction,polymerization and other reactions.Besides,the significant advances in the innovation of microplatform are also covered.The novel reactor configuration methods were established mainly to achieve rapid and efficient data collection and analysis.Finally,the advantages of microfluidic technology for the kinetic measurement are summarized,and a perspective for the future development is provided.

γ-catenin alleviates cardiac fibrosis through inhibiting phosphorylation of GSK-3β

Cardiac fibrosis is a common pathological change of many cardiovascular diseases. β-catenin has been shown to promote fibrosis. However, the precise role of its homolog γ-catenin in the process of fibrosis remains largely unclear. In this study, we found that the expression of γ-catenin was significantly decreased in angiotensin Ⅱ(Ang Ⅱ)-induced cardiac fibrosis model, contrary to most reports of β-catenin. Overexpression of γ-catenin in cardiac fibroblasts(CFs) significantly inhibited the expression of α-smooth muscle actin(α-SMA), whereas knocking down the expression of γ-catenin with si RNA promoted the occurrence of cardiac fibrosis.Mechanistically, γ-catenin could bind to GSK-3β to inhibit the phosphorylation of GSK-3β, therefore preventing cardiac fibrosis. Our study shows that γ-catenin is an important protective factor in cardiac fibrosis, which provides a new potential target for the treatment of cardiac fibrosis.

Tissue Engineering and Regulatory Science

Tissue engineering has successfully evolved from its original concept[1]into medical products with a rapid pace of develop-ment and a multi-billion dollar market[2].Compared with tradi-tional medical products,tissue-engineered medical products(TEMPs)have distinct characteristics that provide unique benefits for the repair and regeneration of damaged or diseased tissues or organs[1,2].

A review of transportation carbon emissions research using bibliometric analyses

The transportation sector is one of the major sources of global carbon emissions.In this study,a bibliometric analysis was conducted using CiteSpace and VOSviewer for articles published in the field of transportation carbon emissions(TCEs)between 1997 and 2023.From this analysis,our research shows that:(a)the number of articles on TCEs has grown rapidly since 2010;(b)China,the United States,and the United Kingdom are important research forces,with the Helmholtz Association of German having the highest number of publications;(c)Transportation Research Part D:Transport and Environment is the most cited journal in this field;(d)the current research hotspots mainly focus on theory and methodological approaches,low-carbon travel,green supply chain management,and carbon emission drivers;(e)while,scenario analysis,data envelopment analysis,and vehicle routing problem are popular keywords that have been used in the research field of TCEs in recent years.Finally,using current research trends,our study also proposes a series of future research endeavors for the field of TCEs.

Cross-sectional rainfall observation on the central-western Tibetan Plateau in the warm season:System design and preliminary results

The central and western Tibetan Plateau(CWTP)is characterized by harsh environment and strong interactions among the spheres of earth as well as significant changes in climate and water cycles over the past four decades.The lack of precipitation observations is a bottleneck for the study of land surface processes in this region.Over the past six years,we have designed and established two observation transects across the south-north and the west-east in this region to obtain hourly rainfall data during the warm season(May-September).The south-north transect extends from Yadong Valley on the southern slope of the Himalayas to Shuanghu County in the hinterland of the plateau,with a total of 31stations;the west-east transect extends from Shiquanhe in the west to Naqu in the central TP,with a total of 22 stations.The observation dataset has been applied to clarify the spatiotemporal characteristics of precipitation in the CWTP,to evaluate the quality of typical gridded precipitation products,to support the development of regional climate models,and to reveal the processes of summertime lake-air interactions.The observation dataset has been released in the National Tibetan Plateau Data Center.

Quick estimation of parameters for the land surface data assimilation system and its influence based on the extended Kalman filter and automatic differentiation

Soil moisture plays a crucial role in drought monitoring,flood forecasting,and water resource management.Data assimilation methods can integrate the strengths of land surface models(LSM)and remote sensing data to generate highprecision and spatio-temporally continuous soil moisture products.However,one of the challenges of the land data assimilation system(LDAS)is how to accurately estimate model and observation errors.To address this,we had previously proposed a dualcycle assimilation algorithm that can simultaneously estimate the model and observation errors,LSM parameters,and observation operator parameters.However,this algorithm requires a large ensemble size to guarantee stable parameter estimates,resulting in low efficiency and limiting its large-scale applications.To address this limitation,the authors employed the following approaches:(1)using automatic differentiation to compute the Jacobian matrix of LSM instead of constructing a tangent linear model of LSM,and(2)replacing the ensemble Kalman filter framework with the extended Kalman filter(EKF)framework to improve the efficiency of parameter optimization for the dual-cycle algorithm.The EKF-based dual-cycle algorithm accelerated the parameter estimation efficiency near 60 times during a 90-day time period with a model integration time step of 1 h.To evaluate the dual-cycle LDAS at the regional-scale,it was applied to assimilate the SMAP soil moisture over the Tibetan Plateau,and soil moisture estimates were validated using in situ observations from four different climatic areas.The results showed that the EKF-based dual-cycle LDAS corrected biases in both the model and observations and produced more accurate estimates of soil moisture,land surface temperature,and evapotranspiration than did the open loop with default parameters.Furthermore,the spatial distribution of soil parameters(sand content,clay content,and porosity)obtained from the LDAS was more reasonable than those of default values.The EKF-based dual-cycle algorithm developed in this study is expected to improve the assimilation skills of land surface,ecological,and hydrological studies.

Regulatory considerations for animal studies of biomaterial products

Animal studies play a vital role in validating the concept,feasibility,safety,performance and efficacy of biomaterials products during their bench-to-clinic translation.This article aims to share regulatory considerations for animal studies of biomaterial products.After briefly emphasizing the importance of animal studies,issues of animal studies during biomaterial products’translation are discussed.Animal studies with unclear purposes,flawed design and poor reporting quality could significantly reduce the translation efficiency and create regulatory challenges.Regulatory perspectives on the purpose,principle,quality and regulatory science of animal studies are also presented.Animal studies should have clear purposes,follow principles of 3R+DQ(replacement,reduction,refinement,design and quality)and execute under an efficiently operating quality management system.With the advancement of regulatory science,National Medical Products Administration of China has been developing a series of standards and guidance documents on animal studies of medical devices.Case studies of making decisions on whether to conduct animal studies are provided in the end with drug-eluting stents as examples.In summary,animal studies of biomaterial products should pay close attention to the rationale,design and quality in order to achieve their purposes.

Regulatory perspectives of combination products

Combination products with a wide range of clinical applications represent a unique class of medical products that are composed of more than a singular medical device or drug/biological product.The product research and development,clinical translation as well as regulatory evaluation of combination products are complex and challenging.This review firstly introduced the origin,definition and designation of combination products.Key areas of systematic regulatory review on the safety and efficacy of device-led/supervised combination products were then presented.Preclinical and clinical evaluation of combination products was discussed.Lastly,the research prospect of regulatory science for combination products was described.New tools of computational modeling and simulation,novel technologies such as artificial intelligence,needs of developing new standards,evidence-based research methods,new approaches including the designation of innovative or breakthrough medical products have been developed and could be used to assess the safety,efficacy,quality and performance of combination products.Taken together,the fast development of combination products with great potentials in healthcare provides new opportunities for the advancement of regulatory review as well as regulatory science.

Weakly coordinating group directed rhodium-catalyzed unconventional site-selective C-H olefination of indolizines at the 8-position

A rhodium-catalyzed directing group promoted selective C-H olefination reaction of indolizines at the 8-position is re ported.Di-olefination at 2,8-positions also achieved with silver hexafluoroantimonate as an additive under similar reaction conditions.Weakly coordinating groups,such as ketone,alde hyde,amide and ester,were used as directing groups.The ester group can be removed under acid conditions and therefore is used as a traceless directing group.