Pericytes protect rats and mice from sepsis-induced injuries by maintaining vascular reactivity and barrier function:implication of miRNAs and microvesicles

Background Vascular hyporeactivity and leakage are key pathophysiologic features that produce multi-organ damage upon sepsis.We hypothesized that pericytes,a group of pluripotent cells that maintain vascular integrity and tension,are protective against sepsis via regulating vascular reactivity and permeability.Methods We conducted a series of in vivo experiments using wild-type(WT),platelet-derived growth factor receptor-β(PDGFR-β)-Cre+mT/mG transgenic mice and Tie2-Cre+Cx43^(flox/flox)mice to examine the relative contribution of pericytes in sepsis,either induced by cecal ligation and puncture(CLP)or lipopolysaccharide(LPS)challenge.In a separate set of experiments with Sprague-Dawley(SD)rats,pericytes were depleted using CP-673451,a selective PDGFR-βinhibitor,at a dosage of 40 mg/(kg·d)for 7 consecutive days.Cultured pericytes,vascular endothelial cells(VECs)and vascular smooth muscle cells(VSMCs)were used for mechanistic investigations.The effects of pericytes and pericyte-derived microvesicles(PCMVs)and candidate miRNAs on vascular reactivity and barrier function were also examined.Results CLP and LPS induced severe injury/loss of pericytes,vascular hyporeactivity and leakage(P<0.05).Transplantation with exogenous pericytes protected vascular reactivity and barrier function via microvessel colonization(P<0.05).Cx43 knockout in either pericytes or VECs reduced pericyte colonization in microvessels(P<0.05).Additionally,PCMVs transferred miR-145 and miR-132 to VSMCs and VECs,respectively,exerting a protective effect on vascular reactivity and barrier function after sepsis(P<0.05).miR-145 primarily improved the contractile response of VSMCs by activating the sphingosine kinase 2(Sphk2)/sphingosine-1-phosphate receptor(S1PR)1/phosphorylation of myosin light chain 20 pathway,whereas miR-132 effectively improved the barrier function of VECs by activating the Sphk2/S1PR2/zonula occludens-1 and vascular endothelial-cadherin pathways.Conclusions Pericytes are protective against sepsis through regulating vascular reactivity and barrier function.Possible mechanisms include both direct colonization of microvasculature and secretion of PCMVs.

Tuning the reactivity of TiO_(2)layer with uniform distribution of Sub-5 nm Fe_(2)O_(3)particles via in situ voltage-assisted oxidation for robust catalytic reduction

The trade-off between efficiency and stability has limited the application of TiO_(2)as a catalyst due to its poor surface reactivity.Here,we present a modification of a TiO_(2)layer with highly stable Sub-5 nm Fe_(2)O_(3)nanoparticles(NP)by modulating its structure-surface reactivity relationship to attain efficiency-stability balance via a voltage-assisted oxidation approach.In situ simultaneous oxidation of the Ti substrate and Fe precursor using high-energy plasma driven by high voltage resulted in uniform distribution of Fe_(2)O_(3)NP embedded within porous TiO_(2)layer.Comprehensive surface characterizations with density functional theory demonstrated an improved electronic transition in TiO_(2)due to the presence of surface defects from reactive oxygen species and possible charge transfer from Ti to Fe;it also unexpectedly increased the active site in the TiO_(2)layer due to uncoordinated electrons in Sub-5 nm Fe_(2)O_(3)NP/TiO_(2)catalyst,thereby enhancing the adsorption of chemical functional groups on the catalyst.This unique embedded structure exhibited remarkable improvement in reducing 4-nitrophenol to 4-aminophenol,achieving approximately 99%efficiency in 20 min without stability decay after 20 consecutive cycles,outperforming previously reported TiO_(2)-based catalysts.This finding proposes a modified-electrochemical strategy enabling facile construction of TiO_(2)with nanoscale oxides extandable to other metal oxide systems.

Wettability,reactivity,and interface structure in Mg/Ni system

The sessile drop method was applied to the experimental investigation of the wetting and spreading behaviors of liquid Mg drops on pure Ni substrates.For comparison,the experiments were performed in two variants:(1)using the Capillary Purification(CP)procedure,which allows the non-contact heating and squeezing of a pure oxide-free Mg drop;(2)by classical Contact Heating(CH)procedure.The high-temperature tests were performed under isothermal conditions(CP:760℃for 30 s;CH:715℃for 300 s)using Ar+5 wt%H_(2) atmosphere.During the sessile drop tests,images of the Mg/Ni couples were recorded by CCD cameras(57 fps),which were then applied to calculate the contact angles of metal/substrate couples.Scanning and transmission electron microscopy analyses,both coupled with energy-dispersive X-ray spectroscopy,were used for detailed structural characterization of the solidified couples.It was found that an oxide-free Mg drop obtained by the CP procedure showed a wetting phenomenon on the Ni substrate(an average contact angleθ<90°in<1 s),followed by fast spreading and good wetting over the Ni substrate(θ_((CP))~20°in 5 s)to form a final contact angle ofθ_(f(CP))~18°.In contrast,a different wetting behavior was observed for the CH procedure,where the unavoidable primary oxide film on the Mg surface blocked the spreading of liquid Mg showing apparently non-wetting behavior after 300 s contact at the test temperature.However,in both cases,the deep craters formed in the Ni substrates under the Mg drops and significant change in the structure of initially pure Mg drops to Mg-Ni alloys suggest a strong dissolution of Ni in liquid Mg and apparent values of the final contact angles measured for the Mg/Ni system.

Correction to:Assembly-level analysis on temperature coefficient of reactivity in a graphite-moderated fuel salt reactor fueled with low-enriched uranium

Following publication of the original article,the authors observed that both Fig.5 and Fig.4 depict the same image.Figure 5 was inaccurately referenced and displayed.The correct Fig.5 is copied below:The original article has been updated.

Evaluation of the Oxidation Reactivity and Behavior of Exhaust Soot Particles from Diesel Engines with Different Emission Levels

The aim of this study was to investigate the oxidation reactivity and behavior of exhaust particulate matter(PM)from diesel engines.PM samples from two diesel engines(1K,CY4102)with different emission levels were collected by a thermophoretic system and a quartz filter.The oxidation reactivity,oxidation behaviors,and physicochemical properties of the PM samples were analyzed using thermogravimetric analysis(TGA),high-resolution transmission electron microscopy(HRTEM),Fourier-transform infrared spectrometry(FTIR),and Raman spectroscopy.The results showed that there was a great difference in the oxidation reactivity of soot particles emitted by the two different diesel engines.A qualitative analysis of the factors influencing oxidation reactivity showed that the nanostructure,degree of graphitization,and relative concentration of aliphatic C—H functional groups were the most important factors,whereas no significant correlation was found between the primary particle size and activation energy of the diesel soot.Based on the oxidation behavior analysis,the diesel soot particles exhibited both internal and surface oxidation modes during the oxidation process.Surface oxidation was dominant during the initial stage,and as oxidation progressed,the mode gradually changed to internal oxidation.Internal oxidation mode of soot particles from the 1K engine was significantly higher than that of CY4102.

Theoretical Investigation on the Stability and Reactivity of Imidazo [1,2-a] Pyridine N-Acylhydrazone Derivatives Using Density Functional Theory

The reactivity and stability of seventeen (17) imidazo [1,2-a]pyridine N-acylhydrazone derivatives were investigated using density functional theory at the B3LYP/6-31+ G (d, p) level. Analysis of the molecular electrostatic potential (MEP) and determination of the dual descriptor revealed that in most cases, the nitrogen atoms of the 6-πelectron conjugation, the oxygen, and the sulfur atom are nucleophilic site. Chemical reactivity of the compounds was assessed through analysis of frontier molecular orbitals (HOMO and LUMO), energy gap (Δℰ), chemical hardness (η), and the softness (S). Consequently, the compound 9e exhibited the lowest reactivity, least electron donating, and the highest stability. This comprehensive study offers valuable insights into the chemical behavior of these derivatives, crucial for further exploration and potential applications.

Experimental Study of the Influence of Intrinsic Parameters on the Thermal Reactivity of Sawdust, Polyethylene Terephthalate and Composite

Several works have been based on the study of thermal variations in biomass to derive more valuable products such as fuels capable of replacing oil in the event of a crisis or activated carbon used as an adsorbent material, widely used in industry for the elimination of unwanted materials, both in liquid and gaseous environments. A study of thermal parameters such as: heating speed, retention time, drying temperature, carbonization temperature, particle size, was carried out with the aim of determining the characteristic factors of the carbonization of Polyethylene terephthalate (PET), sawdust (SC) and sawdust/polyethylene terephthalate (CPS) mixture. The results of the immediate analysis revealed a very low level of ash in PET (0.013%) compared to the level of ash in sawdust (2.9%), as well as a high level of fixed carbon (82.960%), which suggests the presence of mineral oxides and a significant carbon matrix unlike PET, which indicates a very significant organic matrix (essentially made up of organic matter) with the absence of mineral oxides. The study of thermal parameters showed the water loss from Sawdust (SC) and the Sawdust/Polyethylene terephthalate (CPS) mixture, an increase with temperature, unlike that of PET whose variation is essentially zero. Without heat treatment, sawdust alone contains approximately 7% water. The optimal drying temperature for this study is 110˚C for a stay of 24 hours. It appears that the largest mass losses for the PET samples are between 87.19% and 96.05%, followed by that of the mixture, between 47.33% and 64.37%. And the lowest are observed, those of sawdust (from 24.02% to 62.6%). However, here we can say that the influence of the mass is not great, given the slight difference between the losses by temperature. The results of the study of the influence of grain size showed that the differences are insignificant, even if we vary the diameter of the grains from simple to triple. To better minimize physical constraints such as the intragranular diffusibility of the volatile matter and the homogeneity of the temperature in the grains, 75 μm particles are found to be optimal for our study. It can be noted when studying the heating rate that the mass loss at the end of the reaction is approximately the same depending on each precursor material. However, it has been demonstrated that the heating rate strongly influences the nature of the reaction products both for volatile materials and for the solid residue as well as on the kinetic parameters of the chemical reaction. Furthermore, the variation in apparent density shows a decrease as a function of the increase in the residence time of the materials in the reactor. As the carbonization time increases, the apparent density decreases. We note, for the lignocellulosic material, that the apparent density stabilizes after 60 minutes.

Density functional theory study of influence of impurity on electronic properties and reactivity of pyrite

The electronic property of pyrite supercell containing As,Se,Te,Co or Ni hetero atoms were calculated using density functional theory（DFT）,and the reactivities of pyrite with oxygen and xanthate were discussed by frontier orbital methods.The cell volume expands due to the presence of impurity.Co and Ni mainly affect the bands near Fermi levels,while As mainly affects the shallow and deep valence bands,and Se and Te mainly affect the deep valence bands.Electronic density analysis suggests that there exists a strong covalent interaction between hetero atom and its surrounding atoms.By frontier orbital calculation,it is suggested that As,Co and Ni have greater influence on the HOMO and LUMO of pyrite than Se and Te.In addition,pyrite containing As,Co or Ni is easier to oxidize by oxygen than pyrite containing Se or Te,and pyrite containing Co or Ni has greater interaction with collector.These are in agreement with the observed pyrite practice.

Effect of sulfur impurity on coke reactivity and its mechanism

Effect of sulfur impurity on coke reactivity was investigated by simulating petroleum coke with low-impurity pitch coke and impurities doping. And its mechanism was discussed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results show that sulfur has strong catalysis on both air and CO2 reactivity of coke in the case of no other impurity interference. Its catalysis is probably realized by triggering organic sulfur→H2S→SO2→COS and elemental sulfur (Sx)→SO2 and organic sulfur→H2S→COS→Sx→C2S→COS reaction systems during coke?O2 and coke?CO2 reactions, respectively, which are partly circular with functions of increasing carbon consumption and enlarging coke specific surface area.

Adsorption/reaction energetics measured by microcalorimetry and correlated with reactivity on supported catalysts: A review

The formations and transformations of the chemical bonds of reactants and intermediates on cata- lyst surfaces occur in conjunction with the evolution of heat during catalytic reactions. Measure- ment of this evolved heat is helpful in terms of understanding the nature of the interactions be- tween the catalyst and the adsorbed species, and provides insights into the reactivity of the catalyst. Although various techniques have previously been applied to assessments of evolved heat, direct measurements using a Tian-Calvet microcalorimeter are currently the most reliable method for this purpose. In this review, we summarize the relationship between the adsorption/reaction energetics determined by microcalorimetry and the reactivities of supported catalysts, and examine the im- portant role of microcalorimetry in understanding catalytic performance from the energetic point of view.

An Observational Study of the Relationship Between Outcome and Platelet Reactivity in Chinese Patients Undergoing PCI Loading with 600 mg Clopidogrel

Objectives:We sought to determine whether high posttreatment platelet reactivity(HPPR)to a 600 mg loading dose of clopidogrel affects outcomes in Chinese patients with acute coronary syndrome(ACS)following percutaneous coronary intervention(PCI)and to investigate whether there is a relationship between the number of platelet reactivity units(PRUs)and the characteristics of the patients.Background:Although impaired platelet response to clopidogrel is a strong predictor of unfavorable outcome after PCI,the impact of HPPR to a 600 mg loading dose of clopidogrel in Chinese patients with ACS undergoing PCI is still unknown.Methods:We performed observational research on 134 unselected patients with ACS undergoing urgent or planned PCI with a 600 mg loading dose of clopidogrel.Platelet activation was expressed as the PRU value measured by the VerifyNow assay.Results:Among the 134 patients(mean age 60.62 years[standard deviation 9.13 years],60.4%male),there were 46 patients with HPPR(34.3%)and 88 patients without HPPR(65.7%).At a mean follow-up of 6 months(standard deviation 1 month),the rates of cardiac death,unstable angina,and rehospitalization for target lesion revascularization were higher in the HPPR group(19.6%vs.6.8%,P=0.029).Multivariate analysis identifi ed hemoglobin level and sex as independent predictors of the PRU value(y=456.355−1.736 x 1−31.880 x 2,P<0.05).On receiver operating characteristic curve analysis,PRU values could signifi cantly discriminate between patients with and patients without cardiac death,unstable angina,and rehospitalization for target lesion revascularization(area under the curve 0.758,95%confi dence interval 0.62–0.85,P=0.001,P<0.05).Conclusion:In patients with ACS,HPPR to a 600 mg loading dose of clopidogrel is associated with worse outcomes after PCI.There is some relationship between the PRU value and the hemoglobin level and sex.PRU values can predict the prognosis.

Experimental Instrumentation for Measurement of Reactivity Temperature and Voiding Effects at Zero Power Research Reactors

The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its utilization as well as issues connected to its implementation into the reactor core.

Current status of high on-treatment platelet reactivity in patients with coronary or peripheral arterial disease:Mechanisms,evaluation and clinical implications

Antiplatelet therapy with aspirin or clopidogrel or both is the standard care for patients with proven coronary or peripheral arterial disease,especially those undergoing endovascular revascularization procedures. However,despite the administration of the antiplatelet regiments,some patients still experience recurrent cardiovascular ischemic events. So far,it is well documented by several studies that in vitro response of platelets may be extremely variable. Poor antiplatelet effect of clopidogrel or high on-treatment platelet reactivity(HTPR) is under investigation by numerous recent studies. This review article focuses on methods used for the ex vivo evaluation of HTPR,as well as on the possible underlying mechanisms and the clinical consequences of this entity. Alternative therapeutic options and future directions are also addressed.

Reactivity of ambient volatile organic compounds(VOCs) in summer of 2004 in Beijing

Ambient volatile organic compounds （VOCs） were sampled at six sites in Beijing in the summer of 2004 and analyzed by GCMS. The chemical reactivities of 73 quantified VOCs species were evaluated by OH loss rates （LOH） and ozone formation potentials （OFPs）. Top 15 reactive species, mainly alkenes and aromatics, were identified by these two methods, and accounted for more than 70% of total reactivity of VOCs. In urban areas, isoprene was the most reactive species in term of OH loss rate, contributing 11.4% to the LOH of VOCs. While toluene, accounting for 9.4% of OFPs, appeared to have a long-time role in the photochemical processes. Tongzhou site is obviously influenced by local chemical industry, but the other five sites showed typical urban features influenced mainly by vehicular emissions.

Investigation on the catalytic effects of AAEM during steam gasification and the resultant char reactivity in oxygen using Shengli lignite at different forms

The purpose of this study is to investigate the catalytic effects of alkali and alkaline earth metallic species （AAEM） on char conversion during the gasification in steam and the changes in ex-situ char reactivity in oxygen after the gasification in steam using different forms （i.e. H-form, Na-form） of Shengli brown coal. The surface area, AAEM concentration and carbon crystallite of chars were obtained to understand the change in char reactivity. It was found that not only Na concentration and carbon structure were the main factors governing the char reactivity in the atmosphere of steam and oxygen, but also they interacted each other. The presence of Na could facilitate the formation of disordering carbon structure in char, and the amorphous carbon structure would in turn affect the distribution of Na and thus its catalytic performance. The surface area and pore volume had very little relationship with the char＇s reactivity. Addi- tionally, the morphology of chars from different forms of coals were observed using scanning electron microscope （SEM）.

Effect of heat treatment on structure and gasification reactivity of petroleum coke

Petroleum coke was thermally treated on a fixed bed reactor in a temperature range of 1173-1673 K. The changes of the elemental composition and crystalline structure of petroleum coke, with heat treatments as well as the gasification reactivity of the heat-treated petroleum cokes were investigated. The results showed that the petroleum coke was carbonized and grapbitized to a higher degree with increasing heating temperature, while the gasification reactivity decreased. The treatment at temperatures of 1173 and 1473 K significantly enlarged the specific surface area and the pore volume of petroleum coke. Both the specific surface area and the pore volume decreased at 1673 K. An empirical normal distribution function model （NDFM） was found to fit the gasification rates of petroleum coke well. The correlation coefficient of petroleum coke by normal distribution function model at different heat treatment temperatures is between 0.93 and 0.95.

Overproduction of nitric oxide inhibits vascular reactivity in portal hypertensive rats

IM To evaluate the relationship between nitric oxide (NO) and hyperdynamic circulatory status in portal hypertension.METHODS Twenty male SpragueDawley rats (weighing 200g±20g) randomized into two groups, portal hypertension group (n=12) and the controls (n=8). Portal hypertensive models were established by means of graded constriction of the portal vein. The concentrations of nitrite (NO2) in portal vein and peripheral blood were measured to reflect NO levels with flourimetric analysis. The reactivitiy of isolated abdominal aortic rings from partial portal veinconstricted and shamoperated rats was observed by potassium chloride (KCl) (10mmol/L-80mmol/L) and phenylephrine (10-9mol/L10-4mol/L) with or without NO synthase inhibitor NωnitroLarginine (LNNA).RESULTS Serum concentrations of NO2 in portal vein (0766μmol/L±0097μmol/L) and peripheral blood (0687μmol/L±0092μmol/L) were elevated in portal hypertensive rats as compared with those in controls (0613μmol/L±0084μmol/L, 0591μmol/L±0045μmol/L, P<001, respectively). The rates of NO2 in portal vein blood were markedly higher than those in peripheral blood (P<005) of portal hypertensive rats. Abdominal aortic rings from portal veinconstricted rats exhibited significantly impaired contractility to phenylephrine and potassium chloride as compared with the controls. The EC50 values of KCl were markedly higher in portal hypertensive rings (265mmol/L±09mmol/L) than those of the control rings (223mmol/L±17mmol/L, P<001), and so were the EC50 values of phenylephrine (372nmol/L±04nmol/L) vs (281nmol/L±02nmol/L, P<001). After preincubation of rings with LNNA, the difference in EC50 values no longer statistically significant between portal hypertensive and control rings in both KCl (2018mmol/L±08mmol/L, and 194mmol/L±12mmol/L, P>005) and phenylephrine (224nmol/L±18nmol/L, 218nmol/L±14nmol/L, P>005). However, the maximal KCl and phenylephrineinduced contractions were still lower in portal hypertensive rings (KCl: 108g±01g, phenylephrine: 143g±014g) than those of the control rings (KCl: 121g±011g, phenylephrine: 172g±011g, P<005, respectively). This showed that addition of the NO synthase inhibitor LNNA could partially restore contractile responses to KCl and phenylephrine in portal hypertensive rings.CONCLUSION NO overproduction inhibits the vascular reactivity to vasocontrictors, and it might be one of the main causes which results in vasodilatation and hyperdynamic circulatory status in portal hypertension.

Crystal lattice free volume in a study of initiation reactivity of nitramines:Impact sensitivity

More detailed analysis of a mutual relationship of impact sensitivity(detected by sound) and crystal lattice free volume, △V, for the 18 nitramines shows that its course is not unequivocal. For a part of the studied compounds this sensitivity has increased with increase of the AV values, but for fairly big number of nitramines the relationship works in the opposite direction, especially for data of 1,3,5-trinitro-1,3,5-triazinane, 1,3,5,7-tetranitro-1,3,5,7-tetrazocane. and β-and ε-polymorphs of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane. Initiation reactivity of technical ε-polymorph of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane gives the impression by disorderliness in distribution of the actions of forces in its crystal lattice in comparison with its RS(reduced sensitivity) or chemically pure analogue. Limitations of partial shapes of the mentioned relationship by the molecular-structural similarity, and already published information about the decisive factors governing the crystal structure, signalizes a higher influence of the intermolecular interactions in a crystal lattice in comparison with influence of the crystal lattice free volume for initiation of the crystalline EMs.

Crystal lattice free volume in a study of initiation reactivity of nitramines:Friction sensitivity

The relationship between friction sensitivity(FS) and the crystal lattice free space per molecule, △V. of thirteen nitramines is described by a linear equation, divided into a number of the partial relationships with strong limitations by their molecular structure characteristics. Increasing FS due to raising of the △V values is not clearly confirmed. The influence of the △V values on friction sensitivity of nitramines is similar to that of their aza atoms which influence the mutual orientations of nitro groups in neighboring molecules. The dipole-dipole interaction of the oxygen and nitrogen atoms of nitro groups in neighboring nitramine molecules has a major effect on their own FS. In accordance with this interaction, a directly proportional relationship was derived between FS and the intrinsic gas phase molecular volume, V_(int), of the nitramines mentioned, which is divided also into several straight lines according to relatively tight molecular structure similarity. The relationships found again confirm a level of disorder in the distribution of the forces in the crystal lattice of the "common" quality of ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, in comparison with its reduced sensitivity(RS) or chemically pure analogue.

Monomer reactivity ratios for fluoroacrylate and butyl methacrylate in miniemulsion copolymerizations initiated by potassium persulphate

Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion levels were determined by ^1H NMR spectra techniques. The reactivity ratios were evaluated by employing Kellen-Tudos （K-T） methods, which yields the apparent reactivity ratios, rBMA = 0.74, rHFMA = 0.87 and rBMA = 0.73, rTFMA = 0.75, respectively, and Q- and e-values of HFMA and TFMA were calculated by the Alfrey-Price method. The results show that HFMA and TFMA are more active than BMA, and the cross-propagation rate constant is greater than the self-propagation one in these two copolymerizations.