Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.[1,2]Septic shock,the most severe form of sepsis,is characterized by circulatory and cellular/metabolic abnor...Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.[1,2]Septic shock,the most severe form of sepsis,is characterized by circulatory and cellular/metabolic abnormalities,and can increase mortality to>40%.[1-3]Early recognition and risk stratification of septic shock are crucial but challenging because of the heterogeneity of its presentation and progression.展开更多
BACKGROUND Thrombocytopenia is common in patients with sepsis and septic shock.AIM To analyse the decrease in the number of platelets for predicting bloodstream infection in patients with sepsis and septic shock in th...BACKGROUND Thrombocytopenia is common in patients with sepsis and septic shock.AIM To analyse the decrease in the number of platelets for predicting bloodstream infection in patients with sepsis and septic shock in the intensive care unit.METHODS A retrospective analysis of patients admitted with sepsis and septic shock in Xingtai People Hospital was revisited.Patient population characteristics and laboratory data were collected for analysis.RESULTS The study group consisted of 85(39%)inpatients with bloodstream infection,and the control group consisted of 133(61%)with negative results or contamination.The percentage decline in platelet counts(PPCs)in patients positive for pathogens[57.1(41.3-74.6)]was distinctly higher than that in the control group[18.2(5.1–43.1)](P<0.001),whereas the PPCs were not significantly different among those with gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.Using receiver operating characteristic curves,the area under the curve of the platelet drop rate was 0.839(95%CI:0.783-0.895).CONCLUSION The percentage decline in platelet counts is sensitive in predicting bloodstream infection in patients with sepsis and septic shock.However,it cannot identify gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.展开更多
BACKGROUND Despite various therapies to treat sepsis,it is one of the leading causes of mortality in the intensive care unit patients globally.Knowledge about the pathophysiology of sepsis has sparked interest in extr...BACKGROUND Despite various therapies to treat sepsis,it is one of the leading causes of mortality in the intensive care unit patients globally.Knowledge about the pathophysiology of sepsis has sparked interest in extracorporeal therapies(ECT)which are intended to balance the dysregulation of the immune system by removing excessive levels of inflammatory mediators.AIM To review recent data on the use of ECT in sepsis and to assess their effects on various inflammatory and clinical outcomes.METHODS In this review,an extensive English literature search was conducted from the last two decades to identify the use of ECT in sepsis.A total of 68 articles from peer-reviewed and indexed journals were selected excluding publications with only abstracts.RESULTS Results showed that ECT techniques such as high-volume hemofiltration,coupled plasma adsorption/filtration,resin or polymer adsorbers,and CytoSorb®are emerging as adjunct therapies to improve hemodynamic stability in sepsis.CytoSorb®has the most published data in regard to the use in the field of septic shock with reports on improved survival rates and lowered sequential organ failure assessment scores,lactate levels,total leucocyte count,platelet count,interleukin-IL-6,IL-10,and TNF levels.CONCLUSION Clinical acceptance of ECT in sepsis and septic shock is currently still limited due to a lack of large random clinical trials.In addition to patient-tailored therapies,future research developments with therapies targeting the cellular level of the immune response are expected.展开更多
Objective To investigate the effects of the pre-shock state on the mortality of patients with sepsis.Methods We enrolled patients with sepsis admitted to the medical intensive care unit of a tertiary care university h...Objective To investigate the effects of the pre-shock state on the mortality of patients with sepsis.Methods We enrolled patients with sepsis admitted to the medical intensive care unit of a tertiary care university hospital. These patients were then classified into three groups: sepsis, pre-shock state,and septic shock. The primary outcome was the 28-day mortality rate. The secondary outcomes were the 90-day, 180-day, and 1-year mortality rates.Results A total of 303 patients(groups: sepsis 135 [44.6%]), pre-shock state(93 [30.7%]), and septic shock(75 [24.8%]) completed the 1-year follow-up. The mortality rates at 28 days, 90 days, and 180days and 1 year were significantly higher in the pre-shock state group than those of the sepsis group,but significantly lower than those in the septic shock group, especially among older patients. When compared with the pre-shock state group, the sepsis group had significantly lower mortality risks at 28days, 90 days, and 180 days and 1 year, whereas the sepsis shock group had higher mortality risks at these time points.Conclusion The mortality rates of patients in the pre-shock state were notably different from those of patients with sepsis or septic shock. The introduction of a modified sepsis severity classification, which includes sepsis, pre-shock state, and septic shock, could offer valuable additional prognostic information.展开更多
BACKGROUND Postpolypectomy syndrome(PPS)is a rare postoperative complication of colonic polypectomy.It presents with abdominal pain and fever accompanied by coagulopathy and elevated inflammatory markers.Its prognosis...BACKGROUND Postpolypectomy syndrome(PPS)is a rare postoperative complication of colonic polypectomy.It presents with abdominal pain and fever accompanied by coagulopathy and elevated inflammatory markers.Its prognosis is usually good,and it only requires outpatient treatment or observation in a general ward.How-ever,it can be life-threatening.CASE SUMMARY The patient was a 58-year-old man who underwent two colonic polypectomies,each resulting in life-threatening sepsis,septic shock,and coagulopathy.Each of the notable manifestations was a rapid drop in blood pressure,an increase in heart rate,loss of consciousness,and heavy sweating,accompanied by shortness of breath and decreased oxygen in the finger pulse.Based on the criteria of organ dysfunction due to infection,we diagnosed him with sepsis.The patient also experienced severe gastrointestinal bleeding after the second operation.Curiously,he did not complain of any abdominal pain throughout the course of the illness.He had significantly elevated concentrations of inflammatory markers and coagulopathy.Except for the absence of abdominal pain,his fever,significant coagulopathy,and elevated inflammatory marker concentrations were all consistent with PPS.Abdominal computed tomography and superior mesenteric artery computed tomography angiography showed no free air or vascular damage.Thus,the diagnosis of colon perforation was not considered.The final blood culture results indicated Moraxella osloensis.The patient was transferred to the intensive care unit and quickly improved after fluid resuscitation,antibiotic treatment,oxygen therapy,and blood transfusion.CONCLUSION PPS may induce dysregulation of the systemic inflammatory response,which can lead to sepsis or septic shock,even in the absence of abdominal pain.展开更多
Sepsis is a lethal condition characterized by multiple organ dysfunction due to disrupted host responses to severe infections.[1]Aff ected patients often have a Sequential Organ Failure Assessment(SOFA)score≥2.[2]Pat...Sepsis is a lethal condition characterized by multiple organ dysfunction due to disrupted host responses to severe infections.[1]Aff ected patients often have a Sequential Organ Failure Assessment(SOFA)score≥2.[2]Patients with a SOFA score<2 and at least one of the following were considered as“suspected sepsis”:(1)quick SOFA(qSOFA)score≥2;(2)SOFA score=1;or(3)National Early Warning Score(NEWS)4-6.[3]Compared with studies on fluid resuscitation in sepsis patients,there are few studies on fluid management in patients with suspected sepsis.Therefore,we conducted a retrospective cohort study to evaluate the relationship between fluid management and disease progression in suspected sepsis patients.展开更多
BACKGROUND Septic shock is a severe form of sepsis characterised by deterioration in circulatory and cellular-metabolic parameters.Despite standard therapy,the outcomes are poor.Newer adjuvant therapy,such as CytoSorb...BACKGROUND Septic shock is a severe form of sepsis characterised by deterioration in circulatory and cellular-metabolic parameters.Despite standard therapy,the outcomes are poor.Newer adjuvant therapy,such as CytoSorb®extracorporeal haemoadsorption device,has been investigated and shown promising outcome.However,there is a lack of some guidance to make clinical decisions on the use of CytoSorb®haemoadsorption as an adjuvant therapy in septic shock in Indian Setting.Therefore,this expert consensus was formulated.AIM To formulate/establish specific consensus statements on the use of CytoSorb®haemoadsorption treatment based on the best available evidence and contextualised to the Indian scenario.METHODS We performed a comprehensive literature on CytoSorb®haemoadsorption in sepsis,septic shock in PubMed selecting papers published between January 2011 and March 20232021 in English language.The statements for a consensus document were developed based on the summarised literature analysis and identification of knowledge gaps.Using a modified Delphi approach combining evidence appraisal and expert opinion,the following topics related to CytoSorb®in septic shock were addressed:need for adjuvant therapy,initiation timeline,need for Interleukin-6 levels,duration of therapy,change of adsorbers,safety,prerequisite condition,efficacy endpoints and management flowchart.Eleven expert members from critical care,emergency medicine,and the intensive care participated and voted on nine statements and one open-ended question.RESULTS Eleven expert members from critical care,emergency medicine,and the intensive care participated and voted on nine statements and one open-ended question.All 11 experts in the consensus group(100%)participated in the first,second and third round of voting.After three iterative voting rounds and adapting two statements,consensus was achieved on nine statements out of nine statements.The consensus expert panel also recognised the necessity to form an association or society that can keep a registry regarding the use of CytoSorb®for all indications in the open-ended question(Q10)focusing on“future recommendations for CytoSorb®therapy”.CONCLUSION This Indian perspective consensus statement supports and provides guidance on the use of CytoSorb®haemoadsorption as an adjuvant treatment in patients with septic shock to achieve optimal outcomes.展开更多
Objective:Some patients exhibit septic symptoms following laparoscopic surgery,leading to a poor prognosis.Effective clinical subphenotyping is critical for guiding tailored therapeutic strategies in these cases.By id...Objective:Some patients exhibit septic symptoms following laparoscopic surgery,leading to a poor prognosis.Effective clinical subphenotyping is critical for guiding tailored therapeutic strategies in these cases.By identifying predisposing factors for postoperative sepsis,clinicians can implement targeted interventions,potentially improving outcomes.This study outlines a workflow for the subphenotype methodology in the context of laparoscopic surgery,along with its practical application.Methods:This study utilized data routinely available in clinical case systems,enhancing the applicability of our findings.The data included vital signs,such as respiratory rate,and laboratory measures,such as blood sodium levels.The process of categorizing clinical routine data involved technical complexities.A correlation heatmap was used to visually depict the relationships between variables.Ordering points were used to identify the clustering structure and combined with Consensus K clustering methods to determine the optimal categorization.Results:Our study highlighted the intricacies of identifying clinical subphenotypes following laparoscopic surgery,and could thus serve as a valuable resource for clinicians and researchers seeking to explore disease heterogeneity in clinical settings.By simplifying complex methodologies,we aimed to bridge the gap between technical expertise and clinical application,fostering an environment where professional medical knowledge is effectively utilized in subphenotyping research.Conclusion:This tutorial could primarily serve as a guide for beginners.A variety of clustering approaches were explored,and each step in the process contributed to a comprehensive understanding of clinical subphenotypes.展开更多
Prototype experiments were carried out on the explosion-proof performance of the RC blast wall.The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively.The shock wave overpressure was tested in diff...Prototype experiments were carried out on the explosion-proof performance of the RC blast wall.The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively.The shock wave overpressure was tested in different regions.The above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP program.The results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP waveform.Through dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was obtained.According to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are set.The above results can provide a reference for the design and construction of the reinforced concrete blast wall.展开更多
Background: Neonatal sepsis is known to result in 26% of mortalities in children below the age of five worldwide, countries in Sub-Saharan African recording the highest deaths. Although the deaths of neonates have red...Background: Neonatal sepsis is known to result in 26% of mortalities in children below the age of five worldwide, countries in Sub-Saharan African recording the highest deaths. Although the deaths of neonates have reduced world over up to 3.6 million counts, Chilenje General Hospital continues to register significant numbers of neonatal sepsis. This study aimed at investigating the factors associated with neonatal sepsis at Chilenje General Hospital in Lusaka, Zambia. Methods: An institution based cross-sectional study design was conducted at Chilenje General Hospital. Data were collected by the use of a researcher designed questionnaire and analysed using SPSS version 25. Frequencies were used for descriptive analysis while bivariate analysis was used to establish association among risk factors and outcome variables. Variables with significant association at 5% level were further subjected to multivariate analysis at α ≤ 0.05. Results: The study showed that out of 156 neonates, 40.4% (63/156) developed neonatal sepsis. Maternal factors that projected the incidence of sepsis amongst neonates were distance to nearest health facility [AOR: 6.3 (95% CI: 1.8 - 21.3), p = 0.003], occupation [AOR: 5.8 (95% CI: 1.2 - 27.6), p = 0.026], number of antenatal visits [AOR: 6.3 (95% CI: 1.9 - 21.6), p = 0.003], number of vaginal examinations [AOR: 10.8 (95% CI: 2.8 - 42), p = 0.001], and pregnancy induced hypertension [AOR: 5.4 (95% CI: 1.4 - 20), p = 0.013]. Neonatal risk factor which projected the incidence of sepsis was Neonate’s age [AOR: 18.8 (95% CI: 4.9 - 72.5), p = 0.000]. Conclusions: The chance of developing neonatal sepsis was strongly correlated with both mother and child variables, according to the study. In order to lower the chance of the neonate acquiring sepsis, encouraging maternal antenatal care use would assist to detect risk factors during prenatal, perinatal and postnatal care and apply the proper therapies.展开更多
Porous materials are widely used in the field of protection because of their excellent energy absorption characteristics.In this work,a series of polyurethane microscopic models are established and the effect of poros...Porous materials are widely used in the field of protection because of their excellent energy absorption characteristics.In this work,a series of polyurethane microscopic models are established and the effect of porosity on the shock waves is studied with classical molecular dynamics simulations.Firstly,shock Hugoniot relations for different porosities are obtained,which compare well with the experimental data.The pores collapse and form local stress wave,which results in the complex multi-wave structure of the shock wave.The microstructure analysis shows that the local stress increases and the local velocity decreases gradually during the process of pore collapse to complete compaction.Finally,it leads to stress relaxation and velocity homogenization.The shock stress peaks can be fitted with two exponential functions,and the amplitude of attenuation coefficient decreases with the increase of density.Besides,the pore collapse under shock or non-shock are discussed by the entropy increase rate of the system.The energy is dissipated mainly through the multiple interactions of the waves under shock.The energy is dissipated mainly by the friction between atoms under non-shock.展开更多
By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the im...By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the improvement in synchronization control between two-stage light gas gun and the transient Raman spectra acquisition,as well as the sample preparation,the Raman peak of the N-O mode of TATB was firstly observed under shock pressure up to 13.6 GPa,noticeably higher than the upper limit of 8.5 GPa reported in available literatures.By taking into account of the continuous shift of the main peak and other observed Raman peaks,we did not distinguish any structural transition or any new species.Moreover,both the present Raman spectra and the time-resolved radiation of TATB during shock loading showed that TATB exhibits higher chemical stability than previous declaration.To reveal the detailed structural response and evolution of TATB under compression,the density functional theoretical calculations were conducted,and it was found that the pressure make N-O bond lengths shorter,nitro bond angles larger,and intermolecular and intra-molecular hydrogen bond interactions enhanced.The observed red shift of Raman peak was ascribed to the abnormal enhancement of H-bound effect on the scissor vibration mode of the nitro group.展开更多
BACKGROUND:Xuebijing(XBJ)can alleviate the inflammatory response,improve organ function,and shorten the intensive care unit(ICU)stay in patients with pyogenic liver abscess(PLA)complicated with sepsis,but the molecula...BACKGROUND:Xuebijing(XBJ)can alleviate the inflammatory response,improve organ function,and shorten the intensive care unit(ICU)stay in patients with pyogenic liver abscess(PLA)complicated with sepsis,but the molecular mechanisms have not been elucidated.This study aimed to explore the molecular mechanism of XBJ in treating PLA complicated with sepsis using a network pharmacology approach.METHODS:The active ingredients and targets of XBJ were retrieved from the ETCM database.Potential targets related to PLA and sepsis were retrieved from the GeneCards,PharmGKB,DisGeNet,Online Mendelian Inheritance in Man(OMIM),Therapeutic Targets Database(TTD),and DrugBank databases.The targets of PLA complicated with sepsis were mapped to the targets of XBJ to identify potential treatment targets.Protein-protein interaction networks were analyzed using the STRING database.Potential treatment targets were imported into the Metascape platform for Gene Ontology(GO)functional enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses.Molecular docking was performed to validate the interactions between active ingredients and core targets.RESULTS:XBJ was found to have 54 potential treatment targets for PLA complicated with sepsis.Interleukin-1β(IL-1β),interleukin-6(IL-6),and tumor necrosis factor(TNF)were identifi ed as core targets.KEGG enrichment analysis revealed important pathways,including the interleukin-17(IL-17)signaling pathway,the TNF signaling pathway,the nuclear factor-kappa B(NF-κB)signaling pathway,and the Toll-like receptor(TLR)signaling pathway.Molecular docking experiments indicated stable binding between XBJ active ingredients and core targets.CONCLUSION:XBJ may exert therapeutic eff ects on PLA complicated with sepsis by modulating signaling pathways,such as the IL-17,TNF,NF-κB,and TLR pathways,and targeting IL-1β,IL-6,and TNF.展开更多
This work focuses on the effect of the interval between two shocks on the ejecta formation from the grooved aluminum(Al_(1100))surface by using smoothed particle hydrodynamics numerical simulation.Two unsupported shoc...This work focuses on the effect of the interval between two shocks on the ejecta formation from the grooved aluminum(Al_(1100))surface by using smoothed particle hydrodynamics numerical simulation.Two unsupported shocks are obtained by the plate-impact between sample and two flyers at interval,with a peak pressure of approximately 30 GPa for each shock.When the shock interval varies from 2.11 to 7.67 times the groove depth,the bubble velocity reduces to a constant,and the micro jetting factor R_(J) from spike to bubble exhibits a non-monotonic change that decreases initially and then increases.At a shock interval of 3.6 times the groove depth,micro jetting factor R_(J) from spike to bubble reaches its minimum value of approximately 0.6.While,the micro jetting factor R_(F) from spike to free surface decreases linearly at first,and stabilizes around 0.25 once the shock interval surpasses 4.18 times the groove depth.When the shock interval is less than 4.18 times the groove depth,the unloading wave generated by the breakout of the first shock wave is superimpose with the unloading part of the second shock wave to form a large tensile area.展开更多
BACKGROUND:The molecular mechanism of sepsis-associated acute kidney injury(SA-AKI)is unclear.We analyzed co-differentially expressed genes(co-DEGs)to elucidate the underlying mechanism and intervention targets of SA-...BACKGROUND:The molecular mechanism of sepsis-associated acute kidney injury(SA-AKI)is unclear.We analyzed co-differentially expressed genes(co-DEGs)to elucidate the underlying mechanism and intervention targets of SA-AKI.METHODS:The microarray datasets GSE65682,GSE30718,and GSE174220 were downloaded from the Gene Expression Omnibus(GEO)database.We identified the co-DEGs and constructed a gene co-expression network to screen the hub genes.We analyzed immune correlations and disease correlations and performed functional annotation of the hub genes.We also performed single-cell and microenvironment analyses and investigated the enrichment pathways and the main transcription factors.Finally,we conducted a correlation analysis to evaluate the role of the hub genes.RESULTS:Interleukin 32(IL32)was identified as the hub gene in SA-AKI,and the main enriched signaling pathways were associated with hemopoiesis,cellular response to cytokine stimulus,inflammatory response,and regulation of kidney development.Additionally,IL32 was significantly associated with mortality in SA-AKI patients.Monocytes,macrophages,T cells,and NK cells were closely related to IL32 and were involved in the immune microenvironment in SA-AKI patients.IL32 expression increased significantly in the kidney of septic mouse.Toll-like receptor 2(TLR2)was significantly and negatively correlated with IL32.CONCLUSION:IL32 is the key gene involved in SA-AKI and is significantly associated with prognosis.TLR2 and relevant immune cells are closely related to key genes.展开更多
The article deals with the motion of the breech block carrier and the weapon casing of an automatic weapon mounted on a flexible carriage and the base of the weapon.Earlier works,which did not consider the dynamic pro...The article deals with the motion of the breech block carrier and the weapon casing of an automatic weapon mounted on a flexible carriage and the base of the weapon.Earlier works,which did not consider the dynamic properties of the base of the weapon,did not allow to reconcile the calculated and experimental results of the weapon casing displacement when shooting from firing rests.For the analysis of the motion of individual parts,the methods of mathematical modelling and firing experiments using a high-speed camera were chosen.Calculations show the best accord with experiment when modelling the system with 4 degrees of freedom.The oscillation of the system regarding the movement of the breech block carrier and the weapon casing was investigated under changed conditions of rate of fire,the use of a muzzle brake and different types of shock absorbers.The velocities and displacements of the weapon casing and the breech block carrier at different values of the impulse of the gases to the breech block carrier were determined.展开更多
In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting conse...In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting consequences.To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(F-200)and 400.0 kg/m3(F-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual protection.Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged.The shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic characteristics.The overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness.For the same thickness,F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials.In this study,as the materials are not destroyed,F-200 with a thickness more than10.0 mm,F-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.Further,multi-layer flexible composites are designed.Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance.Within the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively.The overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density.展开更多
Chemical inclusions significantly alter shock responses of crystalline explosives in macroscale gap experiments but their microscale dynamics origin remains unclear.Herein shock-induced energy localization,overall phy...Chemical inclusions significantly alter shock responses of crystalline explosives in macroscale gap experiments but their microscale dynamics origin remains unclear.Herein shock-induced energy localization,overall physical responses,and reactions in a-1,3,5-trinitro-1,3,5-triazinane(a-RDX)crystal entrained various chemical inclusions were investigated by the multi-scale shock technique implemented in the reactive molecular dynamics method.Results indicated that energy localization and shock reaction were affected by the intrinsic factors within chemical inclusions,i.e.,phase states,chemical compositions,and concentrations.The atomic origin of chemical-inclusions effects on energy localization is dependent on the dynamics mechanism of interfacial molecules with free space volume,which includes homogeneous intermolecular compression,interfacial impact and shear,and void collapse and jet.As introducing various chemical inclusions,the initiation of those dynamics mechanisms triggers diverse decay rates of bulk RDX molecules and hereby impacts on growth speeds of final reactions.Adding chemical inclusions can reduce the effectiveness of the void during the shock impacting.Under the shockwave velocity of 9 km/s,the parent RDX decay rate in RDX entrained amorphous carbon decreases the most and is about one fourth of that in RDX with a vacuum void,and solid HMX and TATB inclusions are more reactive than amorphous carbon but less reactive than dry air or acetone inclusions.The lessdense shocking system denotes the greater increases in local temperature and stress,the faster energy liberation,and the earlier final reaction into equilibrium,revealing more pronounced responses to the present intense shockwave.The quantitative models associated with the relative system density(RD_(sys))were proposed for indicating energy-localization mechanisms and evaluating initiation safety in the shocked crystalline explosive.RD_(sys)is defined by the density ratio of defective RDX to perfect crystal after dynamics relaxation and reveals the global density characteristic in shocked systems filled with chemical inclusions.When RD_(sys)is below 0.9,local hydrodynamic jet initiated by void collapse dominates upon energy localization instead of interfacial impact.This study sheds light on novel insights for understanding the shock chemistry and physical-based atomic origin in crystalline explosives considering chemical-inclusions effects.展开更多
Background: To examine the differences in prevalence of respiratory distress syndrome, early-onset sepsis and jaundice, between late preterm infants versus term infants in Ecuadorian newborns. Methods: Study design: E...Background: To examine the differences in prevalence of respiratory distress syndrome, early-onset sepsis and jaundice, between late preterm infants versus term infants in Ecuadorian newborns. Methods: Study design: Epidemiological, observational, and cross-sectional, with two cohorts of patients. Settings: IESS Quito Sur Hospital at Quito, Ecuador, from February to April of 2020. Participants: This study included 204 newborns, 102 preterm infants, 102 term infants. Results: There are significant differences between late preterm infants and term infants, with a p-value of 0.000 in the prevalence of early sepsis, 70.59% vs. 35.29%. In respiratory distress syndrome between late and term premature infants, significant differences were observed with a p-value of 0.000, the proportion being 55.58% vs. 24.51% respectively. The prevalence of jaundice is higher in term infants with a p value of 0.002, 72.55%, versus 51.96% in late preterm infants, and the mean value of bilirubins in mg/dL was higher in term infants 14.32 versus 12.33 in late preterm infants;this difference is statistically significant with a p value of 0.004. Admission to the NICU is more frequent in late preterm infants with a p-value of 0.000, being 42.16% for late preterm infants vs. 7.84% in term infants;the mean of the hospital days with p-value 0.005, was higher in late preterm infants 4.97 days vs. 3.55 days for term newborns. Conclusion: Due to the conditions of their immaturity, late preterm infants are 2.86 times more likely to present early sepsis than full-term newborns. It is shown that late preterm infants are 2.69 times more likely to have respiratory distress syndrome compared to term infants, therefore, late preterm infants have a longer hospital stay of 4.97 days versus 3.55 days in term infants. Jaundice and mean bilirubin levels are higher in term infants due to blood group incompatibility and insufficient breastfeeding.展开更多
The gun-track launch system is a new special launch device that connects the track outside the muzzle.Because it is constrained by the track,the characteristics of development of the muzzle jet differ from those of th...The gun-track launch system is a new special launch device that connects the track outside the muzzle.Because it is constrained by the track,the characteristics of development of the muzzle jet differ from those of the traditional muzzle jet.Specifically,it changes from freely developing to doing so in a constrained manner,where this results in an asymmetric direction of flow as well as spatio-temporal coupling-induced interference between various shock waves and the formation of vortices.In this background,the authors of this article formulate and consider the development and characteristics of evolution of the muzzle jet as it impacts a constrained moving body.We designed simulations to test the gun-track launch system,and established a numerical model based on the dynamic grid method to explore the development and characteristics of propagation of disturbances when the muzzle jet impacted a constrained moving body.We also considered models without a constrained track for the sake of comparison.The results showed that the muzzle jet assumed a circumferential asymmetric shape,and tended to develop in the area above the muzzle.Because the test platform was close to the ground,the muzzle jet was subjected to reflections from it that enhanced the development and evolution of various forms of shock waves and vortices in the muzzle jet to exacerbate its rate of distortion and asymmetric characteristics.This in turn led to significant differences in the changes in pressure at symmetric points that would otherwise have been identical.The results of a comparative analysis showed that the constrained track could hinder the influence of reflections from the ground on the muzzle jet to some extent,and could reduce the velocity of the shock waves inducing the motion of the muzzle as well as the Mach number of the moving body.The work here provides a theoretical basis and the requisite technical support for applications of the gun-track launch system.It also sheds light on the technical bottlenecks that need to be considered to recover high-value warheads.展开更多
基金supported by the National Natural Science Foundation of China(no.82374069)the Beijing Municipal Administration of Hospitals’Youth Program(no.QML20170105)the Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support“Yangfan”Project(no.ZYLX201802)。
文摘Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.[1,2]Septic shock,the most severe form of sepsis,is characterized by circulatory and cellular/metabolic abnormalities,and can increase mortality to>40%.[1-3]Early recognition and risk stratification of septic shock are crucial but challenging because of the heterogeneity of its presentation and progression.
文摘BACKGROUND Thrombocytopenia is common in patients with sepsis and septic shock.AIM To analyse the decrease in the number of platelets for predicting bloodstream infection in patients with sepsis and septic shock in the intensive care unit.METHODS A retrospective analysis of patients admitted with sepsis and septic shock in Xingtai People Hospital was revisited.Patient population characteristics and laboratory data were collected for analysis.RESULTS The study group consisted of 85(39%)inpatients with bloodstream infection,and the control group consisted of 133(61%)with negative results or contamination.The percentage decline in platelet counts(PPCs)in patients positive for pathogens[57.1(41.3-74.6)]was distinctly higher than that in the control group[18.2(5.1–43.1)](P<0.001),whereas the PPCs were not significantly different among those with gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.Using receiver operating characteristic curves,the area under the curve of the platelet drop rate was 0.839(95%CI:0.783-0.895).CONCLUSION The percentage decline in platelet counts is sensitive in predicting bloodstream infection in patients with sepsis and septic shock.However,it cannot identify gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.
文摘BACKGROUND Despite various therapies to treat sepsis,it is one of the leading causes of mortality in the intensive care unit patients globally.Knowledge about the pathophysiology of sepsis has sparked interest in extracorporeal therapies(ECT)which are intended to balance the dysregulation of the immune system by removing excessive levels of inflammatory mediators.AIM To review recent data on the use of ECT in sepsis and to assess their effects on various inflammatory and clinical outcomes.METHODS In this review,an extensive English literature search was conducted from the last two decades to identify the use of ECT in sepsis.A total of 68 articles from peer-reviewed and indexed journals were selected excluding publications with only abstracts.RESULTS Results showed that ECT techniques such as high-volume hemofiltration,coupled plasma adsorption/filtration,resin or polymer adsorbers,and CytoSorb®are emerging as adjunct therapies to improve hemodynamic stability in sepsis.CytoSorb®has the most published data in regard to the use in the field of septic shock with reports on improved survival rates and lowered sequential organ failure assessment scores,lactate levels,total leucocyte count,platelet count,interleukin-IL-6,IL-10,and TNF levels.CONCLUSION Clinical acceptance of ECT in sepsis and septic shock is currently still limited due to a lack of large random clinical trials.In addition to patient-tailored therapies,future research developments with therapies targeting the cellular level of the immune response are expected.
基金funded by the Clinical Cohort Construction Program of Peking University Third Hospital [No.BYSYDL2021019]the National Natural Science Foundation of China [Grant No. 82272197]。
文摘Objective To investigate the effects of the pre-shock state on the mortality of patients with sepsis.Methods We enrolled patients with sepsis admitted to the medical intensive care unit of a tertiary care university hospital. These patients were then classified into three groups: sepsis, pre-shock state,and septic shock. The primary outcome was the 28-day mortality rate. The secondary outcomes were the 90-day, 180-day, and 1-year mortality rates.Results A total of 303 patients(groups: sepsis 135 [44.6%]), pre-shock state(93 [30.7%]), and septic shock(75 [24.8%]) completed the 1-year follow-up. The mortality rates at 28 days, 90 days, and 180days and 1 year were significantly higher in the pre-shock state group than those of the sepsis group,but significantly lower than those in the septic shock group, especially among older patients. When compared with the pre-shock state group, the sepsis group had significantly lower mortality risks at 28days, 90 days, and 180 days and 1 year, whereas the sepsis shock group had higher mortality risks at these time points.Conclusion The mortality rates of patients in the pre-shock state were notably different from those of patients with sepsis or septic shock. The introduction of a modified sepsis severity classification, which includes sepsis, pre-shock state, and septic shock, could offer valuable additional prognostic information.
基金the Scientific Research Project of the Natural Science Foundation of Changsha,No.kq2202413.
文摘BACKGROUND Postpolypectomy syndrome(PPS)is a rare postoperative complication of colonic polypectomy.It presents with abdominal pain and fever accompanied by coagulopathy and elevated inflammatory markers.Its prognosis is usually good,and it only requires outpatient treatment or observation in a general ward.How-ever,it can be life-threatening.CASE SUMMARY The patient was a 58-year-old man who underwent two colonic polypectomies,each resulting in life-threatening sepsis,septic shock,and coagulopathy.Each of the notable manifestations was a rapid drop in blood pressure,an increase in heart rate,loss of consciousness,and heavy sweating,accompanied by shortness of breath and decreased oxygen in the finger pulse.Based on the criteria of organ dysfunction due to infection,we diagnosed him with sepsis.The patient also experienced severe gastrointestinal bleeding after the second operation.Curiously,he did not complain of any abdominal pain throughout the course of the illness.He had significantly elevated concentrations of inflammatory markers and coagulopathy.Except for the absence of abdominal pain,his fever,significant coagulopathy,and elevated inflammatory marker concentrations were all consistent with PPS.Abdominal computed tomography and superior mesenteric artery computed tomography angiography showed no free air or vascular damage.Thus,the diagnosis of colon perforation was not considered.The final blood culture results indicated Moraxella osloensis.The patient was transferred to the intensive care unit and quickly improved after fluid resuscitation,antibiotic treatment,oxygen therapy,and blood transfusion.CONCLUSION PPS may induce dysregulation of the systemic inflammatory response,which can lead to sepsis or septic shock,even in the absence of abdominal pain.
文摘Sepsis is a lethal condition characterized by multiple organ dysfunction due to disrupted host responses to severe infections.[1]Aff ected patients often have a Sequential Organ Failure Assessment(SOFA)score≥2.[2]Patients with a SOFA score<2 and at least one of the following were considered as“suspected sepsis”:(1)quick SOFA(qSOFA)score≥2;(2)SOFA score=1;or(3)National Early Warning Score(NEWS)4-6.[3]Compared with studies on fluid resuscitation in sepsis patients,there are few studies on fluid management in patients with suspected sepsis.Therefore,we conducted a retrospective cohort study to evaluate the relationship between fluid management and disease progression in suspected sepsis patients.
文摘BACKGROUND Septic shock is a severe form of sepsis characterised by deterioration in circulatory and cellular-metabolic parameters.Despite standard therapy,the outcomes are poor.Newer adjuvant therapy,such as CytoSorb®extracorporeal haemoadsorption device,has been investigated and shown promising outcome.However,there is a lack of some guidance to make clinical decisions on the use of CytoSorb®haemoadsorption as an adjuvant therapy in septic shock in Indian Setting.Therefore,this expert consensus was formulated.AIM To formulate/establish specific consensus statements on the use of CytoSorb®haemoadsorption treatment based on the best available evidence and contextualised to the Indian scenario.METHODS We performed a comprehensive literature on CytoSorb®haemoadsorption in sepsis,septic shock in PubMed selecting papers published between January 2011 and March 20232021 in English language.The statements for a consensus document were developed based on the summarised literature analysis and identification of knowledge gaps.Using a modified Delphi approach combining evidence appraisal and expert opinion,the following topics related to CytoSorb®in septic shock were addressed:need for adjuvant therapy,initiation timeline,need for Interleukin-6 levels,duration of therapy,change of adsorbers,safety,prerequisite condition,efficacy endpoints and management flowchart.Eleven expert members from critical care,emergency medicine,and the intensive care participated and voted on nine statements and one open-ended question.RESULTS Eleven expert members from critical care,emergency medicine,and the intensive care participated and voted on nine statements and one open-ended question.All 11 experts in the consensus group(100%)participated in the first,second and third round of voting.After three iterative voting rounds and adapting two statements,consensus was achieved on nine statements out of nine statements.The consensus expert panel also recognised the necessity to form an association or society that can keep a registry regarding the use of CytoSorb®for all indications in the open-ended question(Q10)focusing on“future recommendations for CytoSorb®therapy”.CONCLUSION This Indian perspective consensus statement supports and provides guidance on the use of CytoSorb®haemoadsorption as an adjuvant treatment in patients with septic shock to achieve optimal outcomes.
基金The study was funded by the China National Key Research and Development Program(2022YFC2504503,2023YFC3603104)General Health Science and Technology Program of Zhejiang Province(2024KY1099)+2 种基金the Huadong Medicine Joint Funds of the Zhejiang Provincial Natural Science Foundation of China(LHDMD24H150001)National Natural Science Foundation of China(82272180)the Project of Drug Clinical Evaluate Research of Chinese Pharmaceutical Association(CPA-Z06-ZC-2021e004).
文摘Objective:Some patients exhibit septic symptoms following laparoscopic surgery,leading to a poor prognosis.Effective clinical subphenotyping is critical for guiding tailored therapeutic strategies in these cases.By identifying predisposing factors for postoperative sepsis,clinicians can implement targeted interventions,potentially improving outcomes.This study outlines a workflow for the subphenotype methodology in the context of laparoscopic surgery,along with its practical application.Methods:This study utilized data routinely available in clinical case systems,enhancing the applicability of our findings.The data included vital signs,such as respiratory rate,and laboratory measures,such as blood sodium levels.The process of categorizing clinical routine data involved technical complexities.A correlation heatmap was used to visually depict the relationships between variables.Ordering points were used to identify the clustering structure and combined with Consensus K clustering methods to determine the optimal categorization.Results:Our study highlighted the intricacies of identifying clinical subphenotypes following laparoscopic surgery,and could thus serve as a valuable resource for clinicians and researchers seeking to explore disease heterogeneity in clinical settings.By simplifying complex methodologies,we aimed to bridge the gap between technical expertise and clinical application,fostering an environment where professional medical knowledge is effectively utilized in subphenotyping research.Conclusion:This tutorial could primarily serve as a guide for beginners.A variety of clustering approaches were explored,and each step in the process contributed to a comprehensive understanding of clinical subphenotypes.
基金funded by Key R&D Projects in Hubei Province (Grant No.2020BCA084)Innovative Group Project of Hubei Natural Science Foundation (Grant No.2020CFA043)。
文摘Prototype experiments were carried out on the explosion-proof performance of the RC blast wall.The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively.The shock wave overpressure was tested in different regions.The above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP program.The results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP waveform.Through dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was obtained.According to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are set.The above results can provide a reference for the design and construction of the reinforced concrete blast wall.
文摘Background: Neonatal sepsis is known to result in 26% of mortalities in children below the age of five worldwide, countries in Sub-Saharan African recording the highest deaths. Although the deaths of neonates have reduced world over up to 3.6 million counts, Chilenje General Hospital continues to register significant numbers of neonatal sepsis. This study aimed at investigating the factors associated with neonatal sepsis at Chilenje General Hospital in Lusaka, Zambia. Methods: An institution based cross-sectional study design was conducted at Chilenje General Hospital. Data were collected by the use of a researcher designed questionnaire and analysed using SPSS version 25. Frequencies were used for descriptive analysis while bivariate analysis was used to establish association among risk factors and outcome variables. Variables with significant association at 5% level were further subjected to multivariate analysis at α ≤ 0.05. Results: The study showed that out of 156 neonates, 40.4% (63/156) developed neonatal sepsis. Maternal factors that projected the incidence of sepsis amongst neonates were distance to nearest health facility [AOR: 6.3 (95% CI: 1.8 - 21.3), p = 0.003], occupation [AOR: 5.8 (95% CI: 1.2 - 27.6), p = 0.026], number of antenatal visits [AOR: 6.3 (95% CI: 1.9 - 21.6), p = 0.003], number of vaginal examinations [AOR: 10.8 (95% CI: 2.8 - 42), p = 0.001], and pregnancy induced hypertension [AOR: 5.4 (95% CI: 1.4 - 20), p = 0.013]. Neonatal risk factor which projected the incidence of sepsis was Neonate’s age [AOR: 18.8 (95% CI: 4.9 - 72.5), p = 0.000]. Conclusions: The chance of developing neonatal sepsis was strongly correlated with both mother and child variables, according to the study. In order to lower the chance of the neonate acquiring sepsis, encouraging maternal antenatal care use would assist to detect risk factors during prenatal, perinatal and postnatal care and apply the proper therapies.
基金financial support from National Natural Science Foundation of China(Grant No.12172325)。
文摘Porous materials are widely used in the field of protection because of their excellent energy absorption characteristics.In this work,a series of polyurethane microscopic models are established and the effect of porosity on the shock waves is studied with classical molecular dynamics simulations.Firstly,shock Hugoniot relations for different porosities are obtained,which compare well with the experimental data.The pores collapse and form local stress wave,which results in the complex multi-wave structure of the shock wave.The microstructure analysis shows that the local stress increases and the local velocity decreases gradually during the process of pore collapse to complete compaction.Finally,it leads to stress relaxation and velocity homogenization.The shock stress peaks can be fitted with two exponential functions,and the amplitude of attenuation coefficient decreases with the increase of density.Besides,the pore collapse under shock or non-shock are discussed by the entropy increase rate of the system.The energy is dissipated mainly through the multiple interactions of the waves under shock.The energy is dissipated mainly by the friction between atoms under non-shock.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072299,11902276)the Natural Science Foundation of Sichuan Province(Grant No.2022NSFSC1802)+1 种基金the Basic Research Project of Southwest Jiaotong University(Grant No.2682023ZTPY009)the National Key Laboratory for Shock Wave and Detonation Physics of China(Grant No.JCKYS2019212007)。
文摘By combination of the transient Raman spectroscopic measurement and the density functional theoretical calculations,the structural evolution and stability of TATB under shock compression was investigated.Due to the improvement in synchronization control between two-stage light gas gun and the transient Raman spectra acquisition,as well as the sample preparation,the Raman peak of the N-O mode of TATB was firstly observed under shock pressure up to 13.6 GPa,noticeably higher than the upper limit of 8.5 GPa reported in available literatures.By taking into account of the continuous shift of the main peak and other observed Raman peaks,we did not distinguish any structural transition or any new species.Moreover,both the present Raman spectra and the time-resolved radiation of TATB during shock loading showed that TATB exhibits higher chemical stability than previous declaration.To reveal the detailed structural response and evolution of TATB under compression,the density functional theoretical calculations were conducted,and it was found that the pressure make N-O bond lengths shorter,nitro bond angles larger,and intermolecular and intra-molecular hydrogen bond interactions enhanced.The observed red shift of Raman peak was ascribed to the abnormal enhancement of H-bound effect on the scissor vibration mode of the nitro group.
基金supported by Hunan Province Key Research and Development Program(2020SKC2004).
文摘BACKGROUND:Xuebijing(XBJ)can alleviate the inflammatory response,improve organ function,and shorten the intensive care unit(ICU)stay in patients with pyogenic liver abscess(PLA)complicated with sepsis,but the molecular mechanisms have not been elucidated.This study aimed to explore the molecular mechanism of XBJ in treating PLA complicated with sepsis using a network pharmacology approach.METHODS:The active ingredients and targets of XBJ were retrieved from the ETCM database.Potential targets related to PLA and sepsis were retrieved from the GeneCards,PharmGKB,DisGeNet,Online Mendelian Inheritance in Man(OMIM),Therapeutic Targets Database(TTD),and DrugBank databases.The targets of PLA complicated with sepsis were mapped to the targets of XBJ to identify potential treatment targets.Protein-protein interaction networks were analyzed using the STRING database.Potential treatment targets were imported into the Metascape platform for Gene Ontology(GO)functional enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses.Molecular docking was performed to validate the interactions between active ingredients and core targets.RESULTS:XBJ was found to have 54 potential treatment targets for PLA complicated with sepsis.Interleukin-1β(IL-1β),interleukin-6(IL-6),and tumor necrosis factor(TNF)were identifi ed as core targets.KEGG enrichment analysis revealed important pathways,including the interleukin-17(IL-17)signaling pathway,the TNF signaling pathway,the nuclear factor-kappa B(NF-κB)signaling pathway,and the Toll-like receptor(TLR)signaling pathway.Molecular docking experiments indicated stable binding between XBJ active ingredients and core targets.CONCLUSION:XBJ may exert therapeutic eff ects on PLA complicated with sepsis by modulating signaling pathways,such as the IL-17,TNF,NF-κB,and TLR pathways,and targeting IL-1β,IL-6,and TNF.
基金supported by the Doctoral Research Launch Foundation of Liaoning Province(Grant No.2022-BS-185),Chinathe Science Challenge Project(Grant No.TZ2016001),China+2 种基金the National Natural Science Foundation of China(Grant Nos.11972092,12172056,12002049),Chinathe key Laboratory of Computational Physics(Gant No.HX02021-24)720-24)Shenyang Ligong University Talent Introduction Support Fund,China。
文摘This work focuses on the effect of the interval between two shocks on the ejecta formation from the grooved aluminum(Al_(1100))surface by using smoothed particle hydrodynamics numerical simulation.Two unsupported shocks are obtained by the plate-impact between sample and two flyers at interval,with a peak pressure of approximately 30 GPa for each shock.When the shock interval varies from 2.11 to 7.67 times the groove depth,the bubble velocity reduces to a constant,and the micro jetting factor R_(J) from spike to bubble exhibits a non-monotonic change that decreases initially and then increases.At a shock interval of 3.6 times the groove depth,micro jetting factor R_(J) from spike to bubble reaches its minimum value of approximately 0.6.While,the micro jetting factor R_(F) from spike to free surface decreases linearly at first,and stabilizes around 0.25 once the shock interval surpasses 4.18 times the groove depth.When the shock interval is less than 4.18 times the groove depth,the unloading wave generated by the breakout of the first shock wave is superimpose with the unloading part of the second shock wave to form a large tensile area.
基金supported by Beijing Natural Science Foundation(No.7222162 to Dr.Hui Liu)。
文摘BACKGROUND:The molecular mechanism of sepsis-associated acute kidney injury(SA-AKI)is unclear.We analyzed co-differentially expressed genes(co-DEGs)to elucidate the underlying mechanism and intervention targets of SA-AKI.METHODS:The microarray datasets GSE65682,GSE30718,and GSE174220 were downloaded from the Gene Expression Omnibus(GEO)database.We identified the co-DEGs and constructed a gene co-expression network to screen the hub genes.We analyzed immune correlations and disease correlations and performed functional annotation of the hub genes.We also performed single-cell and microenvironment analyses and investigated the enrichment pathways and the main transcription factors.Finally,we conducted a correlation analysis to evaluate the role of the hub genes.RESULTS:Interleukin 32(IL32)was identified as the hub gene in SA-AKI,and the main enriched signaling pathways were associated with hemopoiesis,cellular response to cytokine stimulus,inflammatory response,and regulation of kidney development.Additionally,IL32 was significantly associated with mortality in SA-AKI patients.Monocytes,macrophages,T cells,and NK cells were closely related to IL32 and were involved in the immune microenvironment in SA-AKI patients.IL32 expression increased significantly in the kidney of septic mouse.Toll-like receptor 2(TLR2)was significantly and negatively correlated with IL32.CONCLUSION:IL32 is the key gene involved in SA-AKI and is significantly associated with prognosis.TLR2 and relevant immune cells are closely related to key genes.
基金supported by the Research project VAROPS(Military autonomous and robotic assets)of the Ministry of Defence of The Czech Republicby the Specific Research Support Project(Grant No.SV22-201)financed from funds of the Ministry of Education,Youth and Sports of The Czech Republic。
文摘The article deals with the motion of the breech block carrier and the weapon casing of an automatic weapon mounted on a flexible carriage and the base of the weapon.Earlier works,which did not consider the dynamic properties of the base of the weapon,did not allow to reconcile the calculated and experimental results of the weapon casing displacement when shooting from firing rests.For the analysis of the motion of individual parts,the methods of mathematical modelling and firing experiments using a high-speed camera were chosen.Calculations show the best accord with experiment when modelling the system with 4 degrees of freedom.The oscillation of the system regarding the movement of the breech block carrier and the weapon casing was investigated under changed conditions of rate of fire,the use of a muzzle brake and different types of shock absorbers.The velocities and displacements of the weapon casing and the breech block carrier at different values of the impulse of the gases to the breech block carrier were determined.
基金supported by the National Natural Science Foundation of China(Grant Nos.12221002,12102233)。
文摘In recent years,explosion shock wave has been considered as a signature injury of the current military conflicts.Although strong shock wave is lethal to the human body,weak shock wave can cause many more lasting consequences.To investigate the protection ability and characteristics of flexible materials and structures under weak shock wave loading,the blast wave produced by TNT explosive is loaded on the polyurethane foam with the density of 200.0 kg/m3(F-200)and 400.0 kg/m3(F-400),polyurea with the density of 1100.0 kg/m^(3)(P-1100)and structures composed of the two materials,which are intended for individual protection.Experimental results indicate that the shock wave is attenuated to weak pressure disturbance after interacting with the flexible materials which are not damaged.The shock wave protective capability of single-layer materials is dependent on their thickness,density and microscopic characteristics.The overpressure,maximum pressure rise rate and impulse of transmitted wave decrease exponentially with increase in sample thickness.For the same thickness,F-400 provides better protective capability than F-200 while P-1100 shows the best protective capability among the three materials.In this study,as the materials are not destroyed,F-200 with a thickness more than10.0 mm,F-400 with a thickness more than 4.0 mm,and P-1100 with a thickness more than 1.0 mm can attenuate the overpressure amplitude more than 90.0%.Further,multi-layer flexible composites are designed.Different layer layouts of designed structures and layer thickness of the single-layer materials can affect the protective performance.Within the research range,the structure in which polyurea is placed on the impact side shows the optimal shock wave protective performance,and the thicknesses of polyurea and polyurethane foam are 1.0 mm and 4.0 mm respectively.The overpressure attenuation rate reached maximum value of 93.3%and impulse attenuation capacity of this structure are better than those of single-layer polyurea and polyurethane foam with higher areal density.
基金the financial support from National Natural Science Foundation of China(Grant Nos.11872119,12172051,and 11972329)Natural Science Foundation of Hubei Province(Grant No.2021CFB120)。
文摘Chemical inclusions significantly alter shock responses of crystalline explosives in macroscale gap experiments but their microscale dynamics origin remains unclear.Herein shock-induced energy localization,overall physical responses,and reactions in a-1,3,5-trinitro-1,3,5-triazinane(a-RDX)crystal entrained various chemical inclusions were investigated by the multi-scale shock technique implemented in the reactive molecular dynamics method.Results indicated that energy localization and shock reaction were affected by the intrinsic factors within chemical inclusions,i.e.,phase states,chemical compositions,and concentrations.The atomic origin of chemical-inclusions effects on energy localization is dependent on the dynamics mechanism of interfacial molecules with free space volume,which includes homogeneous intermolecular compression,interfacial impact and shear,and void collapse and jet.As introducing various chemical inclusions,the initiation of those dynamics mechanisms triggers diverse decay rates of bulk RDX molecules and hereby impacts on growth speeds of final reactions.Adding chemical inclusions can reduce the effectiveness of the void during the shock impacting.Under the shockwave velocity of 9 km/s,the parent RDX decay rate in RDX entrained amorphous carbon decreases the most and is about one fourth of that in RDX with a vacuum void,and solid HMX and TATB inclusions are more reactive than amorphous carbon but less reactive than dry air or acetone inclusions.The lessdense shocking system denotes the greater increases in local temperature and stress,the faster energy liberation,and the earlier final reaction into equilibrium,revealing more pronounced responses to the present intense shockwave.The quantitative models associated with the relative system density(RD_(sys))were proposed for indicating energy-localization mechanisms and evaluating initiation safety in the shocked crystalline explosive.RD_(sys)is defined by the density ratio of defective RDX to perfect crystal after dynamics relaxation and reveals the global density characteristic in shocked systems filled with chemical inclusions.When RD_(sys)is below 0.9,local hydrodynamic jet initiated by void collapse dominates upon energy localization instead of interfacial impact.This study sheds light on novel insights for understanding the shock chemistry and physical-based atomic origin in crystalline explosives considering chemical-inclusions effects.
文摘Background: To examine the differences in prevalence of respiratory distress syndrome, early-onset sepsis and jaundice, between late preterm infants versus term infants in Ecuadorian newborns. Methods: Study design: Epidemiological, observational, and cross-sectional, with two cohorts of patients. Settings: IESS Quito Sur Hospital at Quito, Ecuador, from February to April of 2020. Participants: This study included 204 newborns, 102 preterm infants, 102 term infants. Results: There are significant differences between late preterm infants and term infants, with a p-value of 0.000 in the prevalence of early sepsis, 70.59% vs. 35.29%. In respiratory distress syndrome between late and term premature infants, significant differences were observed with a p-value of 0.000, the proportion being 55.58% vs. 24.51% respectively. The prevalence of jaundice is higher in term infants with a p value of 0.002, 72.55%, versus 51.96% in late preterm infants, and the mean value of bilirubins in mg/dL was higher in term infants 14.32 versus 12.33 in late preterm infants;this difference is statistically significant with a p value of 0.004. Admission to the NICU is more frequent in late preterm infants with a p-value of 0.000, being 42.16% for late preterm infants vs. 7.84% in term infants;the mean of the hospital days with p-value 0.005, was higher in late preterm infants 4.97 days vs. 3.55 days for term newborns. Conclusion: Due to the conditions of their immaturity, late preterm infants are 2.86 times more likely to present early sepsis than full-term newborns. It is shown that late preterm infants are 2.69 times more likely to have respiratory distress syndrome compared to term infants, therefore, late preterm infants have a longer hospital stay of 4.97 days versus 3.55 days in term infants. Jaundice and mean bilirubin levels are higher in term infants due to blood group incompatibility and insufficient breastfeeding.
文摘The gun-track launch system is a new special launch device that connects the track outside the muzzle.Because it is constrained by the track,the characteristics of development of the muzzle jet differ from those of the traditional muzzle jet.Specifically,it changes from freely developing to doing so in a constrained manner,where this results in an asymmetric direction of flow as well as spatio-temporal coupling-induced interference between various shock waves and the formation of vortices.In this background,the authors of this article formulate and consider the development and characteristics of evolution of the muzzle jet as it impacts a constrained moving body.We designed simulations to test the gun-track launch system,and established a numerical model based on the dynamic grid method to explore the development and characteristics of propagation of disturbances when the muzzle jet impacted a constrained moving body.We also considered models without a constrained track for the sake of comparison.The results showed that the muzzle jet assumed a circumferential asymmetric shape,and tended to develop in the area above the muzzle.Because the test platform was close to the ground,the muzzle jet was subjected to reflections from it that enhanced the development and evolution of various forms of shock waves and vortices in the muzzle jet to exacerbate its rate of distortion and asymmetric characteristics.This in turn led to significant differences in the changes in pressure at symmetric points that would otherwise have been identical.The results of a comparative analysis showed that the constrained track could hinder the influence of reflections from the ground on the muzzle jet to some extent,and could reduce the velocity of the shock waves inducing the motion of the muzzle as well as the Mach number of the moving body.The work here provides a theoretical basis and the requisite technical support for applications of the gun-track launch system.It also sheds light on the technical bottlenecks that need to be considered to recover high-value warheads.
