The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have ...The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have been proved to be troublesome and less intuitive. Analytical solutions based on loss-less tube model and average friction tube model are found respectively by using fluid net theory, and they fit the experimental results well. The research work shows that： Fluid net theory can be used to solve the analytical solution of filling and exhausting processes of pneumatic system, and the result of loss-less tube model is close to that of average friction model, so loss-less tube model is recommended since it is simpler, and the difference between filling time and exhausting time is determined by initial and final pressures, the volume of container and the section area of tube, and has nothing to do with the length of the tube.展开更多
A coupled model among flow field,solid temperature,species concentration and gas radiation,which was based on statistical narrow-band correlated-k model,was employed to predict the infrared radiations from hot exhaust...A coupled model among flow field,solid temperature,species concentration and gas radiation,which was based on statistical narrow-band correlated-k model,was employed to predict the infrared radiations from hot exhausting nozzles.The parameters of narrow-band model were deduced from HITEMP line-by-line database.Several methods to increase computational efficiency and to save computational resources were employed,thus all the complicated computations could be operated on a personal computer.The predictions for three cases have been conducted to validate the accuracy of the methods mentioned above,including the temperature distribution of a water-cooling nozzle in rocket engines,the carbon dioxide absorptivity at the wavelength of 4.3 micron and the infrared radiation of a cylindrical furnace.Finally,the aerothermodynamic and infrared characteristics of two nozzles were predicted.It was shown that the infrared radiation intensity of chevron ejecting nozzle were obviously smaller than that of common axisymmetric convergent-divergent nozzle.展开更多
The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical s...The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.展开更多
We show that if a bounded domain Ω is exhausted by a bounded strictly pseudoconvex domain D with C^2 boundary, then Ω is holomorphically equivalent to D or the unit ball, and show that a bounded domain has to be hol...We show that if a bounded domain Ω is exhausted by a bounded strictly pseudoconvex domain D with C^2 boundary, then Ω is holomorphically equivalent to D or the unit ball, and show that a bounded domain has to be holomorphically equivalent to the unit ball if its Fridman's invariant has certain growth condition near the boundary.展开更多
Ethylene(C_(2)H_(4))in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a...Ethylene(C_(2)H_(4))in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a key precursor of PM_(2.5).In this study,a novel MgO-supported Ag-Cu bimetallic catalyst was designed and investigated using density functional theory(DFT).The effects of Ag and Cu loading on the geometric structure,stability,and reactant adsorption characteristics of the catalyst were analyzed,and the catalytic oxidation pathways of C_(2)H_(4)over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C_(2)H_(4).The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C_(2)H_(4).Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C_(2)H_(4)and O_(2),three representative configurations were selected for detailed reaction pathway analysis.Among them,Configuration 6 of AgCu-MgO exhibited the highest catalytic oxidation performance.This study provides new atomic-scale insights for the rational design of efficient catalysts targeting olefinic pollutants in automotive emissions and offers valuable guidance for advancing exhaust after-treatment technologies.展开更多
Extreme heat events contribute to high mortality[1,2]and overwhelm emergency medical services through increased ambulance calls and overcrowded emergency departments.[3]Because morbidity and mortality are directly rel...Extreme heat events contribute to high mortality[1,2]and overwhelm emergency medical services through increased ambulance calls and overcrowded emergency departments.[3]Because morbidity and mortality are directly related to both the degree and duration of hyperthermia,timely recognition and management of heat exhaustion and heat stroke are critical for preventing death and reducing healthcare burdens.展开更多
Exercise produces a decrease in pain sensitivity via an effect called exercise-induced hypoalgesia(EIH).Transcranial direct current stimulation(tDCS),acting on similar analgesic mechanisms as EIH,represents a potentia...Exercise produces a decrease in pain sensitivity via an effect called exercise-induced hypoalgesia(EIH).Transcranial direct current stimulation(tDCS),acting on similar analgesic mechanisms as EIH,represents a potential complementary intervention that may amplify the effects of exercise on pain.This study aimed to explore if anodal tDCS could enhance the effect of exercise on pain compared to exercise alone.A total of 35 healthy participants aged 19–37 years completed a familiarisation session followed by two separate sessions where active and sham tDCS was applied in a randomised cross-over design.The familiarisation session involved familiarisation to the pain assessment and exercise tasks,while the subsequent tDCS sessions involved pain sensitivity assessment,exercise and either anodal tDCS or sham tDCS.tDCS doses were applied at 2 mA over the primary motor cortex for 10 min,with the reference electrode placed over the contralateral supraorbital area.The exercise task involved a sustained isometric grip strength contraction at 35%of maximal voluntary contraction(MVC)until volitional exhaustion.Pain sensitivity was evaluated as pressure pain threshold before tDCS,after tDCS,and after exercise.Across both tDCS conditions,pain threshold was higher after exercise when compared to pre-and post-tDCS measurement.This increase in pain threshold did not differ between active and sham tDCS conditions.Our findings suggest that the hypoalgesic effects of active anodal tDCS over the motor cortex prior to exercise are no greater than the effects of sham tDCS prior to exercise.展开更多
Unmanned combat aerial vehicles require lightweight,stealth-capable exhaust systems.However,traditional metallic nozzles increase radar detectability and reduce range,while advanced composites offer high performance b...Unmanned combat aerial vehicles require lightweight,stealth-capable exhaust systems.However,traditional metallic nozzles increase radar detectability and reduce range,while advanced composites offer high performance but are expensive.Therefore,to improve the operational range and survivability of unmanned combat aerial vehicles,a lightweight,high-temperature-resistant,oxidation-resistant,and low-observable composite exhaust nozzle is developed to replace conventional metallic straight-type nozzles.The nozzle features a double serpentine shape to reduce radar and infrared signatures and is manufactured as a monolithic structure using the filament winding process,accommodating the complex geometry and large size(length:1.8 m,width:0.8 m).The exhaust nozzle consists of a ceramic matrix composite made of silicon carbide fibers and a silicon oxycarbide matrix,which absorbs and scatters radio frequency signals while withstanding prolonged exposure to high-temperature(700℃)oxidizing environments typical of engine exhaust gases.The polysiloxane resin used to produce the silicon oxycarbide matrix poses significant challenges owing to its low tackiness and high viscosity variations depending on the presence of nanoparticles,making filament winding difficult.These challenges are addressed by optimizing resin viscosity and winding pattern design.As a result,the tensile strength of the composite specimens fabricated with the optimized viscosity increases by 228.03% before pyrolysis and 97.68%after pyrolysis,compared with that of the non-optimized specimens.In addition,the density and tensile strength of the composite processed via three cycles of polymer infiltration and pyrolysis increased by 13.08% and 80.37%,respectively,compared to those of the non-densified composite.High-temperature oxidation and flame tests demonstrate exceptional thermal and oxidative stability.Furthermore,when compared with carbon fiber-reinforced ceramic matrix composites,the developed composite exhibits a permittivity at least two levels lower and a reflection loss below7 dB within the frequency range of 9.3-10.9 GHz,underscoring its superior electromagnetic stealth performance.展开更多
In recent years the crucial role of CD4^(+)T cells in tumor immunomodulation has garnered increasing recognition.While conventional cancer immunotherapy research has predominantly focused on the cytotoxic function of ...In recent years the crucial role of CD4^(+)T cells in tumor immunomodulation has garnered increasing recognition.While conventional cancer immunotherapy research has predominantly focused on the cytotoxic function of CD8+T cells,emerging evidence has now shown that CD4^(+)T cells enhance antitumor immunity by delivering co-stimulatory signals,secreting cytokines,and promoting cytotoxic T lymphocyte(CTL)activation and display unique immunoregulatory capabilities through direct tumor cell killing or remodeling of the tumor microenvironment.The high heterogeneity and functional plasticity of CD4^(+)T cell subsets significantly influence clinical responses to immunotherapy with underlying mechanisms involving multi-level regulatory networks,including epigenetic modulation and metabolic reprogramming.Deciphering the functional heterogeneity of CD4^(+)T cells and the interactions with the tumor microenvironment will provide essential mechanistic insights for next-generation immunotherapies,such as immune checkpoint inhibitors and chimeric antigen receptor T(CAR-T)therapies,thereby advancing personalized treatment paradigms.展开更多
As the United States marks the fifth anniversary of the September 11 terrorist attacks, will it change its controversial antiterrorism strategy? Five years after the United States launched its war on terror, the terro...As the United States marks the fifth anniversary of the September 11 terrorist attacks, will it change its controversial antiterrorism strategy? Five years after the United States launched its war on terror, the terrorist threat the world faces is mounting instead of declining, experts say. For many years before the Al Qaeda attacks on the United States on September 11, 2001, the world suffered one major terrorist attack every two years, but since then,展开更多
Background Overtraining Syndrome(OTS)is a condition resulting from excessive physical activity without adequate recovery,predominantly affecting elite athletes and military personnel.While overreaching can be a tempor...Background Overtraining Syndrome(OTS)is a condition resulting from excessive physical activity without adequate recovery,predominantly affecting elite athletes and military personnel.While overreaching can be a temporary state,non-functional overreaching may progress to chronic OTS.This review explores various hypotheses regarding the pathogenesis of OTS,including glycogen depletion,dysregulated cytokine response,oxidative stress,and alterations in the autonomic nervous system function.It also highlights the systemic impact of OTS on multiple organ systems,immune function,and overall health,linking the condition to chronic inflammation and an increased disease susceptibility.Additionally,it addresses the role of the gut microbiome in health modulation through physical activity.Methods This narrative review was conducted through a structured search of peer-reviewed journal articles in databases such as PubMed,Web of Science,and Google Scholar,focusing on studies involving human participants and published in English.Results OTS has systemic effects on multiple organ systems,immune function,and overall health,leading to chronic inflammation and increased disease susceptibility.Athletes with OTS exhibit higher morbidity rates,influenced by factors such as sleep deprivation and stress.The review also emphasizes the role of the gut microbiome as a significant modulator of health through physical activity.Conclusion Balanced training and recovery are crucial for preventing OTS and maintaining optimal health and quality of life in physically active individuals.Understanding the complex pathophysiology of OTS is essential for developing effective prevention and treatment strategies.展开更多
CD8^(+)T cell exhaustion,a critical challenge in the immune response to cancer,is characterized by a profound decline in the functionality of effector CD8^(+)T cells.This state of exhaustion is accompanied by the upre...CD8^(+)T cell exhaustion,a critical challenge in the immune response to cancer,is characterized by a profound decline in the functionality of effector CD8^(+)T cells.This state of exhaustion is accompanied by the upregulation of various inhibitory receptors and significant shifts in both transcriptional and epigenetic profiles,thus ultimately leading to inadequate tumor control.Therapeutic strategies aimed at reversing CD8^(+)T cell exhaustion have the potential to rejuvenate immune responses and enhance treatment efficacy.This review compiles current knowledge regarding the molecular mechanisms underlying CD8^(+)T cell exhaustion,including the roles of immune checkpoint molecules,the tumor microenvironment,metabolic reprogramming,transcription factors,and epigenetic modifications.Emerging therapeutic approaches designed to combat CD8^(+)T cell exhaustion are evaluated,with emphasis on the modulation of immune checkpoints;targeting of metabolic and transcriptional changes;and exploration of other innovative strategies,such as epigenetic editing and engineered CAR-T cells.Importantly,we expand the exhaustion concept to immune cells beyond CD8^(+)T cells,such as CD4^(+)T cells,natural killer cells,and myeloid populations,thereby highlighting the broader implications of systemic immunosuppression in the cancer context.Finally,we propose avenues for future research aimed at further elucidating the factors and molecular mechanisms associated with CD8^(+)T cell exhaustion,thereby underscoring the critical need for strategies aimed at reversing this state to improve outcomes in cancer immunotherapy.展开更多
Objectives:This study aimed to establish the concept of overcoming exhaustion,providing a reference basis for nursing management and conducting related nursing research.Methods:Liehr and Smith’s three-phase,nine-step...Objectives:This study aimed to establish the concept of overcoming exhaustion,providing a reference basis for nursing management and conducting related nursing research.Methods:Liehr and Smith’s three-phase,nine-step concept-building process was used to create the concept of overcoming exhaustion.The nine steps were as follows:1)write a practice story;2)name the emerging concept;3)select a theoretical lens;4)link concept to literature;5)gather a concept story;6)identify final core qualities;7)formulate concept definition;8)create a concept model;and 9)specify the concept building synthesis.Results:The concept of overcoming exhaustion was identified based on the elements of a practice story,the life experiences of nurses who struggle with the demands of caring for their patients,their families,and themselves.The theory of self-transcendence was then recognized as the theoretical lens from which to ground the concept.The core qualities,despair and moments of calmness,were derived from the literature and confirmed through a concept story.A definition of the concept integrating the core qualities was formed:overcoming exhaustion involves realizing moments of calmness amidst despair.A model was created to demonstrate the relationship between core qualities,despair,and moments of calmness.Conclusions:The concept of overcoming exhaustion was developed and,through the concept-building process,was defined as realizing moments of calmness amidst despair.By identifying the complexities of overcoming exhaustion,this work lays the foundation for a future research program to develop understanding and interventions that support nurse well-being in the context of ongoing personal and professional demands.展开更多
Objectives:Emotional exhaustion among healthcare professionals,particularly pharmacists,significantly impacts their well-being and efficacy in patient care.Understanding the psychological mechanisms contributing to em...Objectives:Emotional exhaustion among healthcare professionals,particularly pharmacists,significantly impacts their well-being and efficacy in patient care.Understanding the psychological mechanisms contributing to emotional exhaustion is essential for developing effective interventions.The present research sought to investigate the potential mediating roles of rumination and coping strategies(adaptive and maladaptive)in the relationship between perceived stress and emotional exhaustion among pharmacists.Methods:A cross-sectional survey was carried out between September 2023 and January 2024 involving 576 pharmacists working in public hospitals in Punjab who met the inclusion criteria and actively participated in the study.We employed the Perceived Stress Scale,the Ruminative Response Scale,the Brief Coping Orientation to Problems Experienced Inventory(COPE),and the Oldenburg Burnout Inventory(OLBI)to assess the hypothesized study model.Path analysis was employed to test the hypothesized mediation model,incorporating simple and chain mediation processes.Results:The findings provided empirical evidence supporting a positive association between perceived stress and emotional exhaustion.Rumination significantlymediated this relationship.Further,both adaptive andmaladaptive coping strategieswere found tomediate this relationship,withmaladaptive coping demonstrating amore substantial impact.Conclusion:The chainmediation model demonstrated that rumination and coping strategies(both maladaptive and adaptive)significantly mediate the relationship between perceived stress and emotional exhaustion among pharmacists.Specifically,rumination was found to be a key mediator,with maladaptive coping strategies having a more substantial impact.These findings provide a deeper understanding of the psychological mechanisms contributing to emotional exhaustion in the pharmacy profession.展开更多
The Brief Interactive Optimism Scale (BIOS-G), recently published, was developed to measure optimism based on the interactive personality styles theory in the general population of Mexican adults. It has been validate...The Brief Interactive Optimism Scale (BIOS-G), recently published, was developed to measure optimism based on the interactive personality styles theory in the general population of Mexican adults. It has been validated in both the general population in Mexico and other Latin American countries. This study aims to further consolidate the validity of the BIOS-G in a specific population. The objectives are to assess the psychometric properties of its items, validate its unidimensional structure, describe its distribution, verify its internal consistency, and examine its direct relationship with affective balance and positive affect, as well as its inverse relationship with emotional exhaustion and negative affect among Mexican university teachers. The BIOS-G, the CESQT emotional exhaustion subscale, and Scale of Positive and Negative Experience (SPANE) were administered to a non-probability sample of 213 Mexican university teachers. All items demonstrated discriminative power and internal consistency. The scale showed internal consistency (Green-Yang ordinal ω = 0.74 and McDonald ordinal ω = 0.88). The one-factor model presented good to acceptable fit to the data, with an average variance extracted of 0.65. Its distribution was negatively skewed and mesokurtic. The BIOS-G correlated directly with SPANE’s affective balance and positive emotional experiences and inversely with negative emotional experiences and emotional exhaustion, with moderate strengths of association. Its mean score was higher in men than in women and correlated positively with age. It is concluded that the BIOS-G demonstrates internal consistency and validity evidence among Mexican university teachers, and its use in this specific population is recommended.展开更多
This study investigated the relationship between AI anxiety and deviant behavior,as well as the roles of emotional exhaustion and leader support in this context.The sample comprised 381 Chinese e-commerce employees(72...This study investigated the relationship between AI anxiety and deviant behavior,as well as the roles of emotional exhaustion and leader support in this context.The sample comprised 381 Chinese e-commerce employees(72.7%female,age range 21–36 years).The results of the Process model analysis indicate that AI anxiety significantly is associated with higher deviant behaviour.Emotional exhaustion partially mediates this relationship between AI anxiety and employee deviant behavior exacerbating deviant behaviour.Leader support moderates the AI anxiety effect on emotional exhaustion such that when leader support is low.AI anxiety is associated with higher emotional exhaustion among employees.By implication,high levels of leader support can alleviate AI anxiety of employees.Employer organizations should provide appropriate guidance when introducing AI technology to prevent AI anxiety and associated emotional exhaustion and deviant behavior.展开更多
This paper presented a novel and environmentally friendly approach for recovering platinum group metals(PGMs)from spent automotive exhaust catalysts.The study employed lead slag and waste graphite electrodes as raw ma...This paper presented a novel and environmentally friendly approach for recovering platinum group metals(PGMs)from spent automotive exhaust catalysts.The study employed lead slag and waste graphite electrodes as raw materials,incorporating CaO as an additive to fine-tune the slag's viscosity and density.By reducing FeO in the lead slag using waste graphite electrodes,pure Fe was obtained,effectively trapping the PGMs from the exhausted catalysts.The study explored the effects of reductant addition,trapping duration,slag basicity,and trapping temperature on the recovery rate of PGMs.The results indicated that a maximum recovery rate of 97.86%was achieved when the reductant was added at 1.5 times the theoretical amount,with a trapping duration of 60 minutes,a slag basicity of 0.7,and a trapping temperature of 1600℃.This research offered a greener pathway for the recovery of PGMs from spent automotive exhaust catalysts.展开更多
Scientists have devoted considerable effort overs several decades to reduce automobile exhaust emissions,and one practical and important strategy is the catalytic conversion of nitric oxide(NO)[1].Previous studies hav...Scientists have devoted considerable effort overs several decades to reduce automobile exhaust emissions,and one practical and important strategy is the catalytic conversion of nitric oxide(NO)[1].Previous studies have shown that lanthanide(Ln)metals can catalytically reduce NO.Thus,the reactions of NO with Ln to form lanthanide-nitric oxide(LnNO)complexes have been designed and served as the simplest prototype molecules for studying NO chemisorption on metal surfaces[2].展开更多
The small punch test technique facilitates the convenient acquisition of the mechanical properties of in-service equipment materials and the assessment of their remaining service life through sampling.However,the weld...The small punch test technique facilitates the convenient acquisition of the mechanical properties of in-service equipment materials and the assessment of their remaining service life through sampling.However,the weldability of components with thin walls after small punch sampling,such as ethylene cracking furnace tubes,requires further investigation.Therefore,the weldability of in-service ethylene cracking furnace tubes following small punch sampling was investigated through nondestructive testing,microstructural characterization,and mechanical testing.Additionally,the impact of small punch sampling size and residual stress on the creep performance of the specimens was studied using an improved ductility exhaustion model.The results indicate that both the surface and interior of the weld repair areas on new furnace tubes and service-exposed furnace tubes after small-punch sampling are defect-free,exhibiting good weld quality.The strength of the specimens after weld repair was higher than that before sampling,whereas toughness decreased.Weld repair following small punch sampling of furnace tubes is both feasible and necessary.Furthermore,a linear relationship was observed between specimen thickness,diameter,and creep fracture time.The residual stress of welding affects the creep performance of the specimen under different stresses.展开更多
基金This project is supported by National Natural Science Foundation of China(No.50575209).
文摘The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have been proved to be troublesome and less intuitive. Analytical solutions based on loss-less tube model and average friction tube model are found respectively by using fluid net theory, and they fit the experimental results well. The research work shows that： Fluid net theory can be used to solve the analytical solution of filling and exhausting processes of pneumatic system, and the result of loss-less tube model is close to that of average friction model, so loss-less tube model is recommended since it is simpler, and the difference between filling time and exhausting time is determined by initial and final pressures, the volume of container and the section area of tube, and has nothing to do with the length of the tube.
文摘A coupled model among flow field,solid temperature,species concentration and gas radiation,which was based on statistical narrow-band correlated-k model,was employed to predict the infrared radiations from hot exhausting nozzles.The parameters of narrow-band model were deduced from HITEMP line-by-line database.Several methods to increase computational efficiency and to save computational resources were employed,thus all the complicated computations could be operated on a personal computer.The predictions for three cases have been conducted to validate the accuracy of the methods mentioned above,including the temperature distribution of a water-cooling nozzle in rocket engines,the carbon dioxide absorptivity at the wavelength of 4.3 micron and the infrared radiation of a cylindrical furnace.Finally,the aerothermodynamic and infrared characteristics of two nozzles were predicted.It was shown that the infrared radiation intensity of chevron ejecting nozzle were obviously smaller than that of common axisymmetric convergent-divergent nozzle.
基金supported by Key Laboratory for National Defence of Underwater Observing and Control Technology fund number 9140c2603100805
文摘The underwater heat exhausting source can cause the thermal difference of the surrounding and surface water.In this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and experiment.The results show that the thermal floating distance is related with the sailing velocity of the underwater target.The higher the velocity is,the longer the hot wake is,and the broader the hot scope is.The relative distance of the thermal floating spot is almost in a logarithmic law with the velocity.The experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.
基金Supported by NSFC(Grants Nos.11371025 and 11871451)the University of Chinese Academy of Sciences
文摘We show that if a bounded domain Ω is exhausted by a bounded strictly pseudoconvex domain D with C^2 boundary, then Ω is holomorphically equivalent to D or the unit ball, and show that a bounded domain has to be holomorphically equivalent to the unit ball if its Fridman's invariant has certain growth condition near the boundary.
基金Supported by the National Natural Science Foundation of China Project(22362018)the Yunnan Fundamental Research Projects(202401AS070102)。
文摘Ethylene(C_(2)H_(4))in vehicle exhaust is a highly reactive volatile organic compound(VOC).Its photooxidative reaction with NOx contributes to the formation of O3 and secondary organic aerosols(SOA),the latter being a key precursor of PM_(2.5).In this study,a novel MgO-supported Ag-Cu bimetallic catalyst was designed and investigated using density functional theory(DFT).The effects of Ag and Cu loading on the geometric structure,stability,and reactant adsorption characteristics of the catalyst were analyzed,and the catalytic oxidation pathways of C_(2)H_(4)over AgCu-MgO was elucidated.The results indicate that loading Ag significantly enhances the adsorption of C_(2)H_(4).The incorporation of Cu into Ag-MgO to form a AgCu-MgO bimetallic catalyst(dual atom catalyst,DACS)further improves the oxidative activity toward C_(2)H_(4).Based on the binding energies of the Ag and Cu bimetallic sites and the adsorption energies of C_(2)H_(4)and O_(2),three representative configurations were selected for detailed reaction pathway analysis.Among them,Configuration 6 of AgCu-MgO exhibited the highest catalytic oxidation performance.This study provides new atomic-scale insights for the rational design of efficient catalysts targeting olefinic pollutants in automotive emissions and offers valuable guidance for advancing exhaust after-treatment technologies.
文摘Extreme heat events contribute to high mortality[1,2]and overwhelm emergency medical services through increased ambulance calls and overcrowded emergency departments.[3]Because morbidity and mortality are directly related to both the degree and duration of hyperthermia,timely recognition and management of heat exhaustion and heat stroke are critical for preventing death and reducing healthcare burdens.
文摘Exercise produces a decrease in pain sensitivity via an effect called exercise-induced hypoalgesia(EIH).Transcranial direct current stimulation(tDCS),acting on similar analgesic mechanisms as EIH,represents a potential complementary intervention that may amplify the effects of exercise on pain.This study aimed to explore if anodal tDCS could enhance the effect of exercise on pain compared to exercise alone.A total of 35 healthy participants aged 19–37 years completed a familiarisation session followed by two separate sessions where active and sham tDCS was applied in a randomised cross-over design.The familiarisation session involved familiarisation to the pain assessment and exercise tasks,while the subsequent tDCS sessions involved pain sensitivity assessment,exercise and either anodal tDCS or sham tDCS.tDCS doses were applied at 2 mA over the primary motor cortex for 10 min,with the reference electrode placed over the contralateral supraorbital area.The exercise task involved a sustained isometric grip strength contraction at 35%of maximal voluntary contraction(MVC)until volitional exhaustion.Pain sensitivity was evaluated as pressure pain threshold before tDCS,after tDCS,and after exercise.Across both tDCS conditions,pain threshold was higher after exercise when compared to pre-and post-tDCS measurement.This increase in pain threshold did not differ between active and sham tDCS conditions.Our findings suggest that the hypoalgesic effects of active anodal tDCS over the motor cortex prior to exercise are no greater than the effects of sham tDCS prior to exercise.
基金supported by the Agency for Defense Development Grant Funded by the Korean Government(Grant No.912822501).
文摘Unmanned combat aerial vehicles require lightweight,stealth-capable exhaust systems.However,traditional metallic nozzles increase radar detectability and reduce range,while advanced composites offer high performance but are expensive.Therefore,to improve the operational range and survivability of unmanned combat aerial vehicles,a lightweight,high-temperature-resistant,oxidation-resistant,and low-observable composite exhaust nozzle is developed to replace conventional metallic straight-type nozzles.The nozzle features a double serpentine shape to reduce radar and infrared signatures and is manufactured as a monolithic structure using the filament winding process,accommodating the complex geometry and large size(length:1.8 m,width:0.8 m).The exhaust nozzle consists of a ceramic matrix composite made of silicon carbide fibers and a silicon oxycarbide matrix,which absorbs and scatters radio frequency signals while withstanding prolonged exposure to high-temperature(700℃)oxidizing environments typical of engine exhaust gases.The polysiloxane resin used to produce the silicon oxycarbide matrix poses significant challenges owing to its low tackiness and high viscosity variations depending on the presence of nanoparticles,making filament winding difficult.These challenges are addressed by optimizing resin viscosity and winding pattern design.As a result,the tensile strength of the composite specimens fabricated with the optimized viscosity increases by 228.03% before pyrolysis and 97.68%after pyrolysis,compared with that of the non-optimized specimens.In addition,the density and tensile strength of the composite processed via three cycles of polymer infiltration and pyrolysis increased by 13.08% and 80.37%,respectively,compared to those of the non-densified composite.High-temperature oxidation and flame tests demonstrate exceptional thermal and oxidative stability.Furthermore,when compared with carbon fiber-reinforced ceramic matrix composites,the developed composite exhibits a permittivity at least two levels lower and a reflection loss below7 dB within the frequency range of 9.3-10.9 GHz,underscoring its superior electromagnetic stealth performance.
基金supported by The National Key Research and Development Program of China(Grant No.2021YFA0910100)Healthy Zhejiang One Million People Cohort(Grant No.K-20230085)+6 种基金supported by National Natural Science Foundation of China(Grant Nos.82304946 and 82573745)Post-doctoral Innovative Talent Support Program(Grant No.BX2023375)567 Foundation of Zhejiang Province(Grant No.LMS25H160006)supported by the National Natural Science Foundation of China(Grant No.82473489)the Medical Science and Technology Project of Zhejiang Province(Grant No.WKJ-ZJ-2202)the Natural Science Foundation of Zhejiang Province(Grant No.LBD24H290001)supported by the National Natural Science Foundation of China(Grant No.82403546).
文摘In recent years the crucial role of CD4^(+)T cells in tumor immunomodulation has garnered increasing recognition.While conventional cancer immunotherapy research has predominantly focused on the cytotoxic function of CD8+T cells,emerging evidence has now shown that CD4^(+)T cells enhance antitumor immunity by delivering co-stimulatory signals,secreting cytokines,and promoting cytotoxic T lymphocyte(CTL)activation and display unique immunoregulatory capabilities through direct tumor cell killing or remodeling of the tumor microenvironment.The high heterogeneity and functional plasticity of CD4^(+)T cell subsets significantly influence clinical responses to immunotherapy with underlying mechanisms involving multi-level regulatory networks,including epigenetic modulation and metabolic reprogramming.Deciphering the functional heterogeneity of CD4^(+)T cells and the interactions with the tumor microenvironment will provide essential mechanistic insights for next-generation immunotherapies,such as immune checkpoint inhibitors and chimeric antigen receptor T(CAR-T)therapies,thereby advancing personalized treatment paradigms.
文摘As the United States marks the fifth anniversary of the September 11 terrorist attacks, will it change its controversial antiterrorism strategy? Five years after the United States launched its war on terror, the terrorist threat the world faces is mounting instead of declining, experts say. For many years before the Al Qaeda attacks on the United States on September 11, 2001, the world suffered one major terrorist attack every two years, but since then,
基金supported by the project SVV-2023-260656 and the Cooperatio Program,research area HEAS.
文摘Background Overtraining Syndrome(OTS)is a condition resulting from excessive physical activity without adequate recovery,predominantly affecting elite athletes and military personnel.While overreaching can be a temporary state,non-functional overreaching may progress to chronic OTS.This review explores various hypotheses regarding the pathogenesis of OTS,including glycogen depletion,dysregulated cytokine response,oxidative stress,and alterations in the autonomic nervous system function.It also highlights the systemic impact of OTS on multiple organ systems,immune function,and overall health,linking the condition to chronic inflammation and an increased disease susceptibility.Additionally,it addresses the role of the gut microbiome in health modulation through physical activity.Methods This narrative review was conducted through a structured search of peer-reviewed journal articles in databases such as PubMed,Web of Science,and Google Scholar,focusing on studies involving human participants and published in English.Results OTS has systemic effects on multiple organ systems,immune function,and overall health,leading to chronic inflammation and increased disease susceptibility.Athletes with OTS exhibit higher morbidity rates,influenced by factors such as sleep deprivation and stress.The review also emphasizes the role of the gut microbiome as a significant modulator of health through physical activity.Conclusion Balanced training and recovery are crucial for preventing OTS and maintaining optimal health and quality of life in physically active individuals.Understanding the complex pathophysiology of OTS is essential for developing effective prevention and treatment strategies.
基金supported by grants from the National Natural Science Foundation of China(Grant No.82171810)the Program of Shandong Provincial Scientific and Technological Development of Traditional Chinese Medicine(Grant No.M-2023210)。
文摘CD8^(+)T cell exhaustion,a critical challenge in the immune response to cancer,is characterized by a profound decline in the functionality of effector CD8^(+)T cells.This state of exhaustion is accompanied by the upregulation of various inhibitory receptors and significant shifts in both transcriptional and epigenetic profiles,thus ultimately leading to inadequate tumor control.Therapeutic strategies aimed at reversing CD8^(+)T cell exhaustion have the potential to rejuvenate immune responses and enhance treatment efficacy.This review compiles current knowledge regarding the molecular mechanisms underlying CD8^(+)T cell exhaustion,including the roles of immune checkpoint molecules,the tumor microenvironment,metabolic reprogramming,transcription factors,and epigenetic modifications.Emerging therapeutic approaches designed to combat CD8^(+)T cell exhaustion are evaluated,with emphasis on the modulation of immune checkpoints;targeting of metabolic and transcriptional changes;and exploration of other innovative strategies,such as epigenetic editing and engineered CAR-T cells.Importantly,we expand the exhaustion concept to immune cells beyond CD8^(+)T cells,such as CD4^(+)T cells,natural killer cells,and myeloid populations,thereby highlighting the broader implications of systemic immunosuppression in the cancer context.Finally,we propose avenues for future research aimed at further elucidating the factors and molecular mechanisms associated with CD8^(+)T cell exhaustion,thereby underscoring the critical need for strategies aimed at reversing this state to improve outcomes in cancer immunotherapy.
文摘Objectives:This study aimed to establish the concept of overcoming exhaustion,providing a reference basis for nursing management and conducting related nursing research.Methods:Liehr and Smith’s three-phase,nine-step concept-building process was used to create the concept of overcoming exhaustion.The nine steps were as follows:1)write a practice story;2)name the emerging concept;3)select a theoretical lens;4)link concept to literature;5)gather a concept story;6)identify final core qualities;7)formulate concept definition;8)create a concept model;and 9)specify the concept building synthesis.Results:The concept of overcoming exhaustion was identified based on the elements of a practice story,the life experiences of nurses who struggle with the demands of caring for their patients,their families,and themselves.The theory of self-transcendence was then recognized as the theoretical lens from which to ground the concept.The core qualities,despair and moments of calmness,were derived from the literature and confirmed through a concept story.A definition of the concept integrating the core qualities was formed:overcoming exhaustion involves realizing moments of calmness amidst despair.A model was created to demonstrate the relationship between core qualities,despair,and moments of calmness.Conclusions:The concept of overcoming exhaustion was developed and,through the concept-building process,was defined as realizing moments of calmness amidst despair.By identifying the complexities of overcoming exhaustion,this work lays the foundation for a future research program to develop understanding and interventions that support nurse well-being in the context of ongoing personal and professional demands.
基金supported by Social Policy Grant through Nazarbayev University,Kazakhstan.
文摘Objectives:Emotional exhaustion among healthcare professionals,particularly pharmacists,significantly impacts their well-being and efficacy in patient care.Understanding the psychological mechanisms contributing to emotional exhaustion is essential for developing effective interventions.The present research sought to investigate the potential mediating roles of rumination and coping strategies(adaptive and maladaptive)in the relationship between perceived stress and emotional exhaustion among pharmacists.Methods:A cross-sectional survey was carried out between September 2023 and January 2024 involving 576 pharmacists working in public hospitals in Punjab who met the inclusion criteria and actively participated in the study.We employed the Perceived Stress Scale,the Ruminative Response Scale,the Brief Coping Orientation to Problems Experienced Inventory(COPE),and the Oldenburg Burnout Inventory(OLBI)to assess the hypothesized study model.Path analysis was employed to test the hypothesized mediation model,incorporating simple and chain mediation processes.Results:The findings provided empirical evidence supporting a positive association between perceived stress and emotional exhaustion.Rumination significantlymediated this relationship.Further,both adaptive andmaladaptive coping strategieswere found tomediate this relationship,withmaladaptive coping demonstrating amore substantial impact.Conclusion:The chainmediation model demonstrated that rumination and coping strategies(both maladaptive and adaptive)significantly mediate the relationship between perceived stress and emotional exhaustion among pharmacists.Specifically,rumination was found to be a key mediator,with maladaptive coping strategies having a more substantial impact.These findings provide a deeper understanding of the psychological mechanisms contributing to emotional exhaustion in the pharmacy profession.
文摘The Brief Interactive Optimism Scale (BIOS-G), recently published, was developed to measure optimism based on the interactive personality styles theory in the general population of Mexican adults. It has been validated in both the general population in Mexico and other Latin American countries. This study aims to further consolidate the validity of the BIOS-G in a specific population. The objectives are to assess the psychometric properties of its items, validate its unidimensional structure, describe its distribution, verify its internal consistency, and examine its direct relationship with affective balance and positive affect, as well as its inverse relationship with emotional exhaustion and negative affect among Mexican university teachers. The BIOS-G, the CESQT emotional exhaustion subscale, and Scale of Positive and Negative Experience (SPANE) were administered to a non-probability sample of 213 Mexican university teachers. All items demonstrated discriminative power and internal consistency. The scale showed internal consistency (Green-Yang ordinal ω = 0.74 and McDonald ordinal ω = 0.88). The one-factor model presented good to acceptable fit to the data, with an average variance extracted of 0.65. Its distribution was negatively skewed and mesokurtic. The BIOS-G correlated directly with SPANE’s affective balance and positive emotional experiences and inversely with negative emotional experiences and emotional exhaustion, with moderate strengths of association. Its mean score was higher in men than in women and correlated positively with age. It is concluded that the BIOS-G demonstrates internal consistency and validity evidence among Mexican university teachers, and its use in this specific population is recommended.
基金funded by Guangxi Eco-Engineering Vocational&Technical College Talent Introduction Research Project and 2024 Guangxi Vocational Education Teaching Reform Research Project grant number[GXSTKYZX20240603]and[GXGZJG2024B125]and the APC was funded by GEVT College.
文摘This study investigated the relationship between AI anxiety and deviant behavior,as well as the roles of emotional exhaustion and leader support in this context.The sample comprised 381 Chinese e-commerce employees(72.7%female,age range 21–36 years).The results of the Process model analysis indicate that AI anxiety significantly is associated with higher deviant behaviour.Emotional exhaustion partially mediates this relationship between AI anxiety and employee deviant behavior exacerbating deviant behaviour.Leader support moderates the AI anxiety effect on emotional exhaustion such that when leader support is low.AI anxiety is associated with higher emotional exhaustion among employees.By implication,high levels of leader support can alleviate AI anxiety of employees.Employer organizations should provide appropriate guidance when introducing AI technology to prevent AI anxiety and associated emotional exhaustion and deviant behavior.
基金Funded by the Natural Science Foundation of Henan(No.252300421563)the Key Research Projects of Henan Provincial Colleges and Universities(No.25B450001)+3 种基金the Basic and Frontier Research Project of Nanyang(No.24JCQY032)National Natural Science Foundation of China(No.52201044)the Key Specialized Research&Development and Promotion Project(Scientific and Technological Project)of Henan Province(No.232102221022)the Basic and Frontier Technology Research Project of Nanyang(No.23JCQY1001)。
文摘This paper presented a novel and environmentally friendly approach for recovering platinum group metals(PGMs)from spent automotive exhaust catalysts.The study employed lead slag and waste graphite electrodes as raw materials,incorporating CaO as an additive to fine-tune the slag's viscosity and density.By reducing FeO in the lead slag using waste graphite electrodes,pure Fe was obtained,effectively trapping the PGMs from the exhausted catalysts.The study explored the effects of reductant addition,trapping duration,slag basicity,and trapping temperature on the recovery rate of PGMs.The results indicated that a maximum recovery rate of 97.86%was achieved when the reductant was added at 1.5 times the theoretical amount,with a trapping duration of 60 minutes,a slag basicity of 0.7,and a trapping temperature of 1600℃.This research offered a greener pathway for the recovery of PGMs from spent automotive exhaust catalysts.
基金the National Key Research and Development Program of China(No.2021YFB3501501)the National Natural Science Foundation of China(No.22276013)the Beijing Natural Science Foundation(No.2242009)for financial support,and thank Tianhe2-JK HPC for generous computer time.
文摘Scientists have devoted considerable effort overs several decades to reduce automobile exhaust emissions,and one practical and important strategy is the catalytic conversion of nitric oxide(NO)[1].Previous studies have shown that lanthanide(Ln)metals can catalytically reduce NO.Thus,the reactions of NO with Ln to form lanthanide-nitric oxide(LnNO)complexes have been designed and served as the simplest prototype molecules for studying NO chemisorption on metal surfaces[2].
基金supports provided by the National Natural Science Foundation of China(No.52372330).
文摘The small punch test technique facilitates the convenient acquisition of the mechanical properties of in-service equipment materials and the assessment of their remaining service life through sampling.However,the weldability of components with thin walls after small punch sampling,such as ethylene cracking furnace tubes,requires further investigation.Therefore,the weldability of in-service ethylene cracking furnace tubes following small punch sampling was investigated through nondestructive testing,microstructural characterization,and mechanical testing.Additionally,the impact of small punch sampling size and residual stress on the creep performance of the specimens was studied using an improved ductility exhaustion model.The results indicate that both the surface and interior of the weld repair areas on new furnace tubes and service-exposed furnace tubes after small-punch sampling are defect-free,exhibiting good weld quality.The strength of the specimens after weld repair was higher than that before sampling,whereas toughness decreased.Weld repair following small punch sampling of furnace tubes is both feasible and necessary.Furthermore,a linear relationship was observed between specimen thickness,diameter,and creep fracture time.The residual stress of welding affects the creep performance of the specimen under different stresses.
