A method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed presses

A new method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed mechanical presses was put forward. By analyzing the kinematic characteristics of a center-located slider-crank mechanism whose crank rotates at a constant angular velocity,the kinematic parameters of the slide,connecting rod and crank were formulated approximately. On the basis of the results above,three inertia forces and the input moment in the mechanism during its idle running were investigated and formulated by dynamic analysis. A verification experiment was performed on a slider-crank mechanism at a high-speed press machine. The forces derived from the established formulas were compared respectively with those obtained by the ADAMS software and the classical method of connecting rod mass substitution. It was experimentally found that the proposed formulas have an improved performance over related earlier techniques. By use of these results,a 1 000 kN 1 250 rpm four-point high-speed press machine was designed and manufactured. The slide of this press is driven by four sets of slider-crank mechanisms with symmetrical layout and opposite rotation directions to counterbalance the horizontal inertia forces. Four eccentric counterbalance blocks were designed to counterbalance the vertical force after their mass and equivalent eccentric radius were formulated. The high-speed press machine designed by the proposed counterbalance method has worked with satisfactory performance and good dynamic balance for more than four years in practical production.

Regeneration of the heart:f rom molecular mechanisms to clinical therapeutics

Heart injury such as myocardial infarction leads to cardiomyocyte loss,fibrotic tissue deposition,and scar formation.These changes reduce cardiac contractility,resulting in heart failure,which causes a huge public health burden.Military personnel,compared with civilians,is exposed to more stress,a risk factor for heart diseases,making cardiovascular health management and treatment innovation an important topic for military medicine.So far,medical intervention can slow down cardiovascular disease progression,but not yet induce heart regeneration.In the past decades,studies have focused on mechanisms underlying the regenerative capability of the heart and applicable approaches to reverse heart injury.Insights have emerged from studies in animal models and early clinical trials.Clinical interventions show the potential to reduce scar formation and enhance cardiomyocyte proliferation that counteracts the pathogenesis of heart disease.In this review,we discuss the signaling events controlling the regeneration of heart tissue and summarize current therapeutic approaches to promote heart regeneration after injury.

Drug resistance mechanisms in cancers:Execution of prosurvival strategies

One of the quintessential challenges in cancer treatment is drug resistance.Several mechanisms of drug resistance have been described to date,and new modes of drug resistance continue to be discovered.The phenomenon of cancer drug resistance is now widespread,with approximately 90% of cancer-related deaths associated with drug resistance.Despite significant advances in the drug discovery process,the emergence of innate and acquired mechanisms of drug resistance has impeded the progress in cancer therapy.Therefore,understanding the mechanisms of drug resistance and the various pathways involved is integral to treatment modalities.In the present review,I discuss the different mechanisms of drug resistance in cancer cells,including DNA damage repair,epithelial to mesenchymal transition,inhibition of cell death,alteration of drug targets,inactivation of drugs,deregulation of cellular energetics,immune evasion,tumor-promoting inflammation,genome instability,and other contributing epigenetic factors.Furthermore,I highlight available treatment options and conclude with future directions.

Overview of the immunological mechanisms in hepatitis B virus reactivation:Implications for disease progression and management strategies

Hepatitis B virus(HBV)reactivation is a clinically significant challenge in disease management.This review explores the immunological mechanisms underlying HBV reactivation,emphasizing disease progression and management.It delves into host immune responses and reactivation’s delicate balance,spanning innate and adaptive immunity.Viral factors’disruption of this balance,as are interac-tions between viral antigens,immune cells,cytokine networks,and immune checkpoint pathways,are examined.Notably,the roles of T cells,natural killer cells,and antigen-presenting cells are discussed,highlighting their influence on disease progression.HBV reactivation’s impact on disease severity,hepatic flares,liver fibrosis progression,and hepatocellular carcinoma is detailed.Management strategies,including anti-viral and immunomodulatory approaches,are critically analyzed.The role of prophylactic anti-viral therapy during immunosuppressive treatments is explored alongside novel immunotherapeutic interventions to restore immune control and prevent reactivation.In conclusion,this compre-hensive review furnishes a holistic view of the immunological mechanisms that propel HBV reactivation.With a dedicated focus on understanding its implic-ations for disease progression and the prospects of efficient management stra-tegies,this article contributes significantly to the knowledge base.The more profound insights into the intricate interactions between viral elements and the immune system will inform evidence-based approaches,ultimately enhancing disease management and elevating patient outcomes.The dynamic landscape of management strategies is critically scrutinized,spanning anti-viral and immunomodulatory approaches.The role of prophylactic anti-viral therapy in preventing reactivation during immunosuppressive treatments and the potential of innovative immunotherapeutic interventions to restore immune control and proactively deter reactivation.

Role of methoxy and C_(α)-based substituents in electrochemical oxidation mechanisms and bond cleavage selectivity of β-O-4 lignin model compounds

In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.

Deep tectonics and seismogenic mechanisms of the seismic source zone of the Jishishan M_(s)6.2 earthquake on December 18,2023,at the northeast margin of the Tibetan Plateau

On December 18,2023,an M_(s)6.2 earthquake occurred in Jishishan,Gansu Province,China.This earthquake happened in the eastern region of the Qilian Orogenic Belt,which is situated at the forefront of the NE margin of the Tibetan Plateau(i.e.,Qinghai-Tibet Plateau),encompassing a rhombic-shaped area that intersects the Qilian-Qaidam Basin,Alxa Block,Ordos Block,and South China Block.In this study,we analyzed the deep tectonic pattern of the Jishishan earthquake by incorporating data on the crustal thickness,velocity structure,global navigation satellite system(GNSS)strain field,and anisotropy.We discovered that the location of the earthquake was related to changes in the crustal structure.The results showed that the Jishishan M_(s)6.2 earthquake occurred in a unique position,with rapid changes in the crustal thickness,Vp/Vs,phase velocity,and S-wave velocity.The epicenter of the earthquake was situated at the transition zone between high and low velocities and was in proximity to a low-velocity region.Additionally,the source area is flanked by two high-velocity anomalies from the east and west.The principal compressive strain orientation near the Lajishan Fault is primarily in the NNE and NE directions,which align with the principal compressive stress direction in this region.In some areas of the Lajishan Fault,the principal compressive strain orientations show the NNW direction,consistent with the direction of the upper crustal fast-wave polarization from local earthquakes and the phase velocity azimuthal anisotropy.These features underscore the relationship between the occurrence of the Jishishan M_(s)6.2 earthquake and the deep inhomogeneous structure and deep tectonic characteristics.The NE margin of the Tibetan Plateau was thickened by crustal extension in the process of northeastward expansion,and the middle and lower crustal materials underwent structural deformation and may have been filled with salt-containing fluids during the extension process.The presence of this weak layer makes it easier for strong earthquakes to occur through the release of overlying rigid crustal stresses.However,it is unlikely that an earthquake of comparable or larger magnitude would occur in the short term(e.g.,in one year)at the Jishishan east margin fault.

Interplay between temperature-dependent strengthening mechanisms and mechanical stability in high-performance austenitic stainless steels

The effects of deformation temperature on the transformation-induced plasticity(TRIP)-aided 304L,twinning-induced plasti-city(TWIP)-assisted 316L,and highly alloyed stable 904L austenitic stainless steels were compared for the first time to tune the mechan-ical properties,strengthening mechanisms,and strength-ductility synergy.For this purpose,the scanning electron microscopy(SEM),electron backscattered diffraction(EBSD),X-ray diffraction(XRD),tensile testing,work-hardening analysis,and thermodynamics calcu-lations were used.The induced plasticity effects led to a high temperature-dependency of work-hardening behavior in the 304L and 316L stainless steels.As the deformation temperature increased,the metastable 304L stainless steel showed the sequence of TRIP,TWIP,and weakening of the induced plasticity mechanism;while the disappearance of the TWIP effect in the 316L stainless steel was also observed.However,the solid-solution strengthening in the 904L superaustenitic stainless steel maintained the tensile properties over a wide temper-ature range,surpassing the performance of 304L and 316L stainless steels.In this regard,the dependency of the total elongation on the de-formation temperature was less pronounced for the 904L alloy due to the absence of additional plasticity mechanisms.These results re-vealed the importance of solid-solution strengthening and the associated high friction stress for superior mechanical behavior over a wide temperature range.

A molecular dynamics study on mechanical performance and deformation mechanisms in nanotwinned NiCo-based alloys with nano-precipitates under high temperatures

Molecular dynamics simulations are performed to investigate the mechanical behavior of nanotwinned NiCo-based alloys containing coherent L12 nano-precipitates at different temperatures,as well as the interactions between the dislocations and nano-precipitates within the nanotwins.The simulation results demonstrate that both the yield stress and flow stress in the nanotwinned NiCo-based alloys with nano-precipitates decrease as the temperature rises,because the higher temperatures lead to the generation of more defects during yielding and lower dislocation density during plastic deformation.Moreover,the coherent L12 phase exhibits excellent thermal stability,which enables the hinderance of dislocation motion at elevated temperatures via the wrapping and cutting mechanisms of dislocations.The synergistic effect of nanotwins and nano-precipitates results in more significant strengthening behavior in the nanotwinned NiCo-based alloys under high temperatures.In addition,the high-temperature mechanical behavior of nanotwinned NiCo-based alloys with nano-precipitates is sensitive to the size and volume fraction of the microstructures.These findings could be helpful for the design of nanotwins and nano-precipitates to improve the high-temperature mechanical properties of NiCo-based alloys.

Activity-dependent mechanisms of neuroprotection:promising avenues against dementia

The study of the brain and its complex functions is highly fascinating and,at the same time,extremely important.Indeed,furthering our understanding of the biology of neurons and synapses is a prerequisite to uncover the mechanisms involved in memory formation and the coordination of movement as well as their alterations occurring in several neurological disorders.

Wnt/β-catenin signaling components and mechanisms in bone formation,homeostasis,and disease

Wnts are secreted,lipid-modified proteins that bind to different receptors on the cell surface to activate canonical or non-canonical Wnt signaling pathways,which control various biological processes throughout embryonic development and adult life.Aberrant Wnt signaling pathway underlies a wide range of human disease pathogeneses.

Contribution of mechanical forces to structural synaptic plasticity:insights from 3D cellular motility mechanisms

Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these forces.Intrinsic and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse formation.In the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called plasticity.Synaptic plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).

Obituary:Prof.Yun Zhang(1963-2023)-A scientist focused on toxins and their underlying mechanisms to decipher human diseases

Prof.Yun Zhang was born on 9 July 1963 in Kunming,Yunnan,China,during a tumultuous period which he often referenced.Throughout his life,he harbored a steadfast belief in using knowledge to unravel the mysteries of human diseases.His educational journey was marked by frequent changes in schools due to his parents’occupational relocations.However,despite these challenges,he consistently displayed diligence and was admitted to the East China University of Science and Technology,Shanghai,after completing high school in 1980.He remained an active and loyal member of the School of Biotechnology at the university.

Chlorfenapyr poisoning:mechanisms,clinical presentations,and treatment strategies

BACKGROUND:Chlorfenapyr is used to kill insects that are resistant to organophosphorus insecticides.Chlorfenapyr poisoning has a high mortality rate and is difficult to treat.This article aims to review the mechanisms,clinical presentations,and treatment strategies for chlorfenapyr poisoning.DATA RESOURCES:We conducted a review of the literature using PubMed,Web of Science,and SpringerLink from their beginnings to the end of October 2023.The inclusion criteria were systematic reviews,clinical guidelines,retrospective studies,and case reports on chlorfenapyr poisoning that focused on its mechanisms,clinical presentations,and treatment strategies.The references in the included studies were also examined to identify additional sources.RESULTS:We included 57 studies in this review.Chlorfenapyr can be degraded into tralopyril,which is more toxic and reduces energy production by inhibiting the conversion of adenosine diphosphate to adenosine triphosphate.High fever and altered mental status are characteristic clinical presentations of chlorfenapyr poisoning.Once it occurs,respiratory failure occurs immediately,ultimately leading to cardiac arrest and death.Chlorfenapyr poisoning is diflcult to treat,and there is no specific antidote.CONCLUSION:Chlorfenapyr is a new pyrrole pesticide.Although it has been identified as a moderately toxic pesticide by the World Health Organization(WHO),the mortality rate of poisoned patients is extremely high.There is no specific antidote for chlorfenapyr poisoning.Therefore,based on the literature review,future efforts to explore rapid and effective detoxification methods,reconstitute intracellular oxidative phosphorylation couplings,identify early biomarkers of chlorfenapyr poisoning,and block the conversion of chlorfenapyr to tralopyril may be helpful for emergency physicians in the diagnosis and treatment of this disease.

Controllable Condensation of Aromatics and Its Mechanisms in Carbonization

In order to obtain liquefied products with higher yields of aromatic molecules to produce mesophase pitch,a good understanding of the relevant reaction mechanisms is required.Reactive molecular dynamics simulations were used to study the thermal reactions of pyrene,1-methylpyrene,7,8,9,10-tetrahydrobenzopyrene,and mixtures of pyrene with 1-octene,cyclohexene,or styrene.The reactant conversion rates,reaction rates,and product distributions were calculated and compared,and the mechanisms were analyzed and discussed.The results demonstrated that methyl and naphthenic structures in aromatics might improve the conversion rates of reactants in hydrogen transfer processes,but their steric hindrances prohibited the generation of high polymers.The naphthenic structures could generate more free radicals and presented a more obvious inhibition effect on the condensation of polymers compared with the methyl side chains.It was discovered that when different olefins were mixed with pyrene,1-octene primarily underwent pyrolysis reactions,whereas cyclohexene mainly underwent hydrogen transfer reactions with pyrene and styrene,mostly producing superconjugated biradicals through condensation reactions with pyrene.In the mixture systems,the olefins scattered aromatic molecules,hindering the formation of pyrene trimers and higher polymers.According to the reactive molecular dynamics simulations,styrene may enhance the yield of dimer and enable the controlled polycondensation of pyrene.

Computational Simulation of Aptamer-target Binding Mechanisms

Aptamers are a type of single-chain oligonucleotide that can combine with a specific target.Due to their simple preparation,easy modification,stable structure and reusability,aptamers have been widely applied as biochemical sensors for medicine,food safety and environmental monitoring.However,there is little research on aptamer-target binding mechanisms,which limits their application and development.Computational simulation has gained much attention for revealing aptamer-target binding mechanisms at the atomic level.This work summarizes the main simulation methods used in the mechanistic analysis of aptamer-target complexes,the characteristics of binding between aptamers and different targets(metal ions,small organic molecules,biomacromolecules,cells,bacteria and viruses),the types of aptamer-target interactions and the factors influencing their strength.It provides a reference for further use of simulations in understanding aptamer-target binding mechanisms.

Evaluation on Configuration Stiffness of Overconstrained 2R1T Parallel Mechanisms

Currently,two rotations and one translation(2R1T)three-degree-of-freedom(DOF)parallel mechanisms(PMs)are widely applied in five-DOF hybrid machining robots.However,there is a lack of an effective method to evaluate the configuration stiffness of mechanisms during the mechanism design stage.It is a challenge to select appropriate 2R1T PMs with excellent stiffness performance during the design stage.Considering the operational status of 2R1T PMs,the bending and torsional stiffness are considered as indices to evaluate PMs'configuration stiffness.Subsequently,a specific method is proposed to calculate these stiffness indices.Initially,the various types of structural and driving stiffness for each branch are assessed and their specific values defined.Subsequently,a rigid-flexible coupled force model for the over-constrained 2R1T PM is established,and the proposed evaluation method is used to analyze the configuration stiffness of the five 2R1T PMs in the entire workspace.Finally,the driving force and constraint force of each branch in the whole working space are calculated to further elucidate the stiffness evaluating results by using the proposed method above.The obtained results demonstrate that the bending and torsional stiffness of the 2RPU/UPR/RPR mechanism along the x and y-directions are larger than the other four mechanisms.

A robust low-friction triple network hydrogel based on multiple synergistic enhancement mechanisms

Hydrogels exhibit promising applications,particularly due to their high water content and excellent biocompatibility.Despite notable progress in hydrogel technology,the concurrent enhancement of water content,mechanical strength,and low friction poses substantial challenges to practical utilization.In this study,employing molecular and network design guided based on multiple synergistic enhancement mechanisms,we have developed a robust polyvinyl alcohol(PVA)-polyacrylic acid(PAA)-polyacrylamide(PAAm)three-network(TN)hydrogel exhibiting high water content,enhanced strength,low friction,and fatigue resistance.The hydrogel manifests a water content of 63.7%,compression strength of 6.3 MPa,compression modulus of 2.68 MPa,tensile strength reaching 7.3 MPa,and a tensile modulus of 10.27 MPa.Remarkably,even after one million cycles of dynamic loading,the hydrogel exhibits no signs of fatigue failure,with a minimal strain difference of only 1.15%.Furthermore,it boasts a low sliding coefficient of friction(COF)of 0.043 and excellent biocompatibility.This advancement extends the applications of hydrogels in emerging fields within biomedicine and soft bio-devices,including load-bearing artificial tissues,artificial blood vessels,tissue scaffolds,robust hydrogel coatings for medical devices,and joint parts of soft robots.

Bioactivities,Mechanisms,Production,and Potential Application of Bile Acids in Preventing and Treating Infectious Diseases

Infectious diseases are a global public health problem,with emerging and re-emerging infectious diseases on the rise worldwide.Therefore,their prevention and treatment are still major challenges.Bile acids are common metabolites in both hosts and microorganisms that play a significant role in controlling the metabolism of lipids,glucose,and energy.Bile acids have historically been utilized as first-line,valuable therapeutic agents for related metabolic and hepatobiliary diseases.Notably,bile acids are the major active ingredients of cow bezoar and bear bile,which are commonly used traditional Chinese medicines(TCMs)with the therapeutic effects of clearing heat,detoxification,and relieving wind and spasm.In recent years,the promising performance of bile acids against infectious diseases has attracted attention from the scientific community.This paper reviews for the first time the biological activities,possible mechanisms,production routes,and potential applications of bile acids in the treatment and prevention of infectious diseases.Compared with previous reviews,we comprehensively summarize existing studies on the use of bile acids against infectious diseases caused by pathogenic microorganisms that are leading causes of global morbidity and mortality.In addition,to ensure a stable supply of bile acids at affordable prices,it is necessary to clarify the biosynthesis of bile acids in vivo,which will assist scientists in elucidating the accumulation of bile acids and discovering how to engineer various bile acids by means of chemosynthesis,biosynthesis,and chemoenzymatic synthesis.Finally,we explore the current challenges in the field and recommend a development strategy for bile-acid-based drugs and the sustainable production of bile acids.The presented studies suggest that bile acids are potential novel therapeutic agents for managing infectious diseases and can be artificially synthesized in a sustainable way.

Mechanisms and active substances of targeting lipid peroxidation in ferroptosis regulation

Ferroptosis is a novel form of cell death driven by iron-dependent lipid peroxidation and it is implicated in various diseases,such as liver disease,acute kidney injury,cardiovascular disease,neurodegenerative disease and cancer.Lipid-based reactive oxygen species(ROS),particularly lipid hydroperoxides in the cellular membrane can lead to membrane disruption and cell death mediated by ferroptosis.There are three necessary stages involving in the process of lipid peroxidation regulation in ferroptosis,including the synthesis of membrane phospholipids,initiation of lipid peroxidation and clearance of lipid peroxides.In this review,we summarized the molecular modulation mechanisms of lipid peroxidation in ferroptosis from the above three stages,as well as various ferroptosis modulators targeting lipid peroxidation,including commonly used products,natural bioactive compounds and selenocompounds.Collectively,these findings suggest the vital role of lipid peroxidation in ferroptosis,and targeting lipid peroxidation in ferroptosis is potential to treat ferroptosis-associated diseases.

Research advances on encapsulation of probiotics with nanomaterials and their repair mechanisms on intestinal barriers

Probiotics participate in various physiological activities and contribute to body health.However,their viability and bioefficacy are adversely affected by gastrointestinal harsh conditions,such as gastric acid,bile salts and various enzymes.Fortunately,encapsulation based on various nanomaterials shows tremendous potential to protect probiotics.In this review,we introduced some novel encapsulation technologies involving nanomaterials in view of predesigned stability and viability,selective adhesion,smart release and colonization,and efficacy exertion of encapsulated probiotics.Furthermore,the interactions between encapsulated probiotics and the gastrointestinal tract were summarized and analyzed,with highlighting the regulatory mechanisms of encapsulated probiotics on intestinal mechanical barrier,chemical barrier,biological barrier and immune barrier.This review would benefit the food and pharmaceutical industries in preparation and utilization of multifunctional encapsulated probiotics.