This paper details the development and testing of the first working prototype of the S-band high-power klystron,accomplished at the Budker Institute of Nuclear Physics,Siberian Branch,Russian Academy of Sciences(BINP ...This paper details the development and testing of the first working prototype of the S-band high-power klystron,accomplished at the Budker Institute of Nuclear Physics,Siberian Branch,Russian Academy of Sciences(BINP SB RAS).Upon testing,the klystron demonstrated the following parameters:an operating frequency of 2856 MHz and a peak power output of 50 MW.The paper presents the klystron's design,its constituent units,and pertinent processing procedures,along with discussions on the measurement of its parameters.展开更多
An innovative double-ejection micro-cathode arc thruster(AC_(d-μ)CAT),which consists of a cylindrical inner anode,a cylindrical outer cathode and two insulating sleeves(an inner insulating sleeve and an outer insulat...An innovative double-ejection micro-cathode arc thruster(AC_(d-μ)CAT),which consists of a cylindrical inner anode,a cylindrical outer cathode and two insulating sleeves(an inner insulating sleeve and an outer insulating sleeve),was proposed.The differences in electrical characteristics,plasma parameters and propulsion performance between the newly proposed AC_(d-μ)CAT and a traditionalμCAT were examined.Study results showed that compared to the traditionalμCAT structure,by using the AC_(d-μ)CAT,the peak value of produced thrust was increased 9.3 times,while the amplitude of the ion current and the ion-to-arc ratio were increased 5.4 and 5.9 times(from 1.2%to 7.1%),respectively.In addition,data from Langmuir probe experiments indicated that peak values of the directional propagation speed and density of plasma plume were increased 3.1 times and 4.2 times,respectively.Moreover,plasma plume directional ejection performance was also significantly improved.This study result will provide support for the development of a new-generationμCAT.展开更多
One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized heterojunctions.Herein,novel Bi_(4)O_5Br_(2)/NH_(2)-MIL-125(...One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized heterojunctions.Herein,novel Bi_(4)O_5Br_(2)/NH_(2)-MIL-125(Ti)Z-scheme heterojunctions are fabricated and used as photocatalysts for organic pollutant photodegradation.The NH_(2)-MIL-125(Ti)nanosheets are exfoliated via a self-developed alkali solution stripping approach and then uniformly decorated on Bi_(4)O_(5)Br_(2).The as-prepared Bi_(4)O_(5)Br_(2)/NH_(2)-MIL-125(Ti)presents more than 90%degradation of various pollutants,outperforming the counterpart individual ones.The various characterization results suggest that the enhanced degradation rate is due to the more intimate face-to-face interfacial contact of the lamellar Z-scheme heterojunction materials,in which the migration path of carriers from the material's interior to the surface can be reduced,in turn enhancing migration efficiency and separation capability significantly.A possible photocatalytic reaction mechanism is proposed based on the photoelectric behaviors,radical trapping experiments and liquid chromatography mass spectrometry analysis.This work promotes the development of new photocatalytic materials for heterojunctions with face-to-face interfacial contacts,as well as the effective purification of wastewater in environmental remediation.展开更多
BACKGROUND Lower gastrointestinal bleeds(LGIB)is a very common inpatient condition in the United States.Gastrointestinal bleeds have a variety of presentations,from minor bleeding to severe hemorrhage and shock.Althou...BACKGROUND Lower gastrointestinal bleeds(LGIB)is a very common inpatient condition in the United States.Gastrointestinal bleeds have a variety of presentations,from minor bleeding to severe hemorrhage and shock.Although previous studies investigated the efficacy of colonoscopy in hospitalized patients with LGIB,there is limited research that discusses disparities in colonoscopy utilization in patients with LGIB in urban and rural settings.AIM To investigate the difference in utilization of colonoscopy in lower gastrointestinal bleeding between patients hospitalized in urban and rural hospitals.METHODS This is a retrospective cohort study of 157748 patients using National Inpatient Sample data and the Healthcare Cost and Utilization Project provided by the Agency for Healthcare Research and Quality.It includes patients 18 years and older hospitalized with LGIB admitted between 2010 and 2016.This study does not differentiate between acute and chronic LGIB and both are included in this study.The primary outcome measure of this study was the utilization of colonoscopy among patients in rural and urban hospitals admitted for lower gastrointestinal bleeds;the secondary outcome measures were in-hospital mortality,length of stay,and costs involved in those receiving colonoscopy for LGIB.Statistical analyses were all performed using STATA software.Logistic regression was used to analyze the utilization of colonoscopy and mortality,and a generalized linear model was used to analyze the length of stay and cost.RESULTS Our study found that 37.9%of LGIB patients at rural hospitals compared to approximately 45.1%at urban hospitals received colonoscopy,(OR=0.730,95%CI:0.705-0.7,P>0.0001).After controlling for covariates,colonoscopies were found to have a protective association with lower inhospital mortality[OR=0.498,95%CI:0.446-0.557,P<0.0001],but a longer length of stay by 0.72 d(95%CI:0.677-0.759 d,P<0.0001)and approximately$2199 in increased costs.CONCLUSION Although there was a lower percentage of LGIB patients that receiv展开更多
Phosphate deficiency is one of the leading causes of crop productivity loss.Phospholipid degradation liberates phosphate to cope with phosphate deficiency.Glycerophosphodiester phosphodiesterases(GPX-PDEs)hydrolyse th...Phosphate deficiency is one of the leading causes of crop productivity loss.Phospholipid degradation liberates phosphate to cope with phosphate deficiency.Glycerophosphodiester phosphodiesterases(GPX-PDEs)hydrolyse the intermediate products of phospholipid catabolism glycerophosphodiesters into glycerol-3-phosphate,a precursor of phosphate.However,the function of GPX-PDEs in phosphate remobilization in maize remains unclear.In the present study,we characterized two phosphate deficiency-inducible GPX-PDE genes,ZmGPX-PDE1 and ZmGPX-PDE5,in maize leaves.ZmGPX-PDE1 and ZmGPX-PDE5 were transcriptionally regulated by ZmPHR1,a well-described phosphate starvation-responsive transcription factor of the MYB family.Complementation of the yeast GPX-PDE mutant gde1Δindicated that ZmGPX-PDE1 and ZmGPX-PDE5 functioned as GPX-PDEs,suggesting their roles in phosphate recycling from glycerophosphodiesters.In vitro enzyme assays showed that ZmGPX-PDE1 and ZmGPX-PDE5 catalysed glycerophosphodiester degradation with different substrate preferences for glycerophosphoinositol and glycerophosphocholine,respectively.ZmGPX-PDE1 was upregulated during leaf senescence,and more remarkably,loss of ZmGPXPDE1 inmaize compromised the remobilization of phosphorus fromsenescing leaves to young leaves,resulting in a stay-green phenotype under phosphate starvation.These results suggest that ZmGPX-PDE1 catalyses the degradation of glycerophosphodiesters in maize,promoting phosphate recycling from senescing leaves to new leaves.This mechanism is crucial for improving phosphorus utilization efficiency in crops.展开更多
BACKGROUND Necrotizing enterocolitis(NEC)is a multifactorial disease that predominantly affects premature neonates.Intestinal dysbiosis plays a critical role in NEC pathogenesis in premature neonates.The main risk fac...BACKGROUND Necrotizing enterocolitis(NEC)is a multifactorial disease that predominantly affects premature neonates.Intestinal dysbiosis plays a critical role in NEC pathogenesis in premature neonates.The main risk factor for NEC in term infants is mesenteric hypoperfusion associated with ductaldependent congenital heart disease(CHD)that eventually leads to intestinal ischemia.The incidence of NEC in neonates with critical CHD is 6.8%-13%.However,the role of the intestinal microbiome in NEC pathogenesis in infants with ductal-dependent CHD remains unclear.CASE SUMMARY A male term neonate with right atrial isomerism underwent modified Blalock-Taussig shunt placement on the 14^(th)day of life and had persistent mesenteric hypoperfusion after surgery.The patient had episodes of NEC stageⅡA on the 1^(st)and 28^(th)days after cardiac surgery.Fecal microbial composition was analyzed before and after cardiac surgery by sequencing region V4 of the 16S rRNA gene.Before surgery,species belonging to genera Veillonella and Clostridia and class Gammaproteobacteria were detected,Bifidobacteriaceae showed a low abundance.The first NEC episode was associated with postoperative hemodynamic instability,intestinal ischemiareperfusion injury during cardiopulmonary bypass,and a high abundance of Clostridium paraputrificum(Clostridium sensu stricto I)(56.1%).Antibacterial therapy after the first NEC episode resulted in increased abundance of Gammaproteobacteria,decreased abundance of Firmicutes,and low alpha diversity.These changes in the microbial composition promoted the growth of Clostridium sensu strictoⅠ(72.0%)before the second NEC episode.CONCLUSION A high abundance of Clostridium sensu strictoⅠand mesenteric hypoperfusion may have contributed to NEC in the present case.展开更多
Electrocatalytic urea oxidation reaction(UOR)is regarded as an effective yet challenging approach for the degradation of urea in wastewater into harmless N2 and CO_(2).To overcome the sluggish kinetics,catalytically a...Electrocatalytic urea oxidation reaction(UOR)is regarded as an effective yet challenging approach for the degradation of urea in wastewater into harmless N2 and CO_(2).To overcome the sluggish kinetics,catalytically active sites should be rationally designed to maneuver the multiple key steps of intermediate adsorption and desorption.Herein,we demonstrate that metal-organic frameworks(MOFs)can provide an ideal platform for tailoring binary active sites to facilitate the rate-determining steps,achieving remarkable electrocatalytic activity toward UOR.Specifically,the MOF(namely,NiMn_(0.14)-BDC)based on Ni/Mn sites and terephthalic acid(BDC)ligands exhibits a low voltage of 1.317 V to deliver a current density of 10 mA cm^(-2).As a result,a high turnover frequency(TOF)of 0.15 s^(-1) is achieved at a voltage of 1.4 V,which enables a urea degradation rate of 81.87%in 0.33 M urea solution.The combination of experimental characterization with theoretical calculation reveals that the Ni and Mn sites play synergistic roles in maneuvering the evolution of urea molecules and key reaction intermediates during the UOR,while the binary Ni/Mn sites in MOF offer the tunability for electronic structure and d-band center impacting on the intermediate evolution.This work provides important insights into active site design by leveraging MOF platform and represents a solid step toward highly efficient UOR with MOF-based electrocatalysts.展开更多
Accurate diagnosis of different bronchopul- monary diseases is important in clinical practice. This study involved 20 healthy volunteers and 77 patients with bronchopulmonary diseases, including chronic obstructive pu...Accurate diagnosis of different bronchopul- monary diseases is important in clinical practice. This study involved 20 healthy volunteers and 77 patients with bronchopulmonary diseases, including chronic obstructive pulmonary disease （COPD）, bronchial asthma, pulmonary tuberculosis, and community-acquired pneumonia. The absorption spectrum of exhaled air samples was recorded on an intra-cavity photo-acoustic gas analyzer （ILPA-1, Special Technologies, Ltd., Russia） with photo-acoustic detectors and CO2 laser with a tuning range from 9.2 to 10.8μm. In conclusion, analysis of the Mahalanobis distance-based absorption spectral profiles of breath air from bronchopulmonary patients and healthy volunteers allows the formulation of a preliminary diagnosis.展开更多
Results of investigations of band structure, Fermi surface and effective masses of charge carriers in the ultrathin (monolayer graphene)/MnO(001) and MnO(001) films are presented using the method of the density functi...Results of investigations of band structure, Fermi surface and effective masses of charge carriers in the ultrathin (monolayer graphene)/MnO(001) and MnO(001) films are presented using the method of the density functional theory. Features of spin states of valence band and Fermi level as well as an interatomic interaction in these systems are discussed. A magnetic moment at Mn atom is estimated and an effect of spin polarization at atoms of oxygen and carbon has been revealed which natures are discussed. By calculations of structural energies for 2D (monolayer graphene)/MnO(001) and 2D MnO(001) a stability of these systems has been ascertained. In the 2D (monolayer graphene)/MnO(001) and 2D MnO(001) systems the band structure calculations for the 2D systems mentioned above point out that tensor components of effective masses of both electrons and holes are in the ranges of (0.15 - 0.54) m0 and (0.38 - 1.27) m0 respectively. Mobility estimations of two-dimensional charge carriers for a 2D (monolayer graphene)/MnO(001)AF2 heterostructure have been performed.展开更多
In this paper, developed wireless portable infrared pyrometer with dual channel fiber optic is described. The pyrometer measures surface temperature in wide infrared spectral range of 2 - 25 um. A data processing algo...In this paper, developed wireless portable infrared pyrometer with dual channel fiber optic is described. The pyrometer measures surface temperature in wide infrared spectral range of 2 - 25 um. A data processing algorithm based on the methods of synchronous detection providing展开更多
Iron-based products account the main volume of powder metallurgy production. Nevertheless its strength and reliability are not enough in comparison with classical cast materials. So that is why making nanostructural p...Iron-based products account the main volume of powder metallurgy production. Nevertheless its strength and reliability are not enough in comparison with classical cast materials. So that is why making nanostructural powder materials allows to increase strength and extend the range of products. A principally new way of nanostructure production is possible by means of iron mechanical alloying with nitride-forming and nitrogen both at the same time. Unlike classical technology of internal nitrogenation, nitrogen saturation, in our case, occurs by whole volume at plastic deformation conditions. A review of experimental results of phase forming alloys in the Fe-Ni, Fe-Ni-Cr, Fe-Ni-N, Fe-Ni-Cr-N, Fe-Cr-Ni systems prepared by mechanical alloying are given. The influence of the technological parameters of mechanical alloying, atmosphere of mechanical activation on nitrogen content and phase composition of examined alloys has been studied. Experimental results of the influence of mechanical alloying technological parameters on degree of ammonia dissociation and nitrogen content in examined alloys are presented. Heat treatment influence of mechanically alloyed, nitrogen-containing alloys on their phase composition and structure are investigated. It was shown that using mechanical alloying, it’s possible to prepare high-alloyed iron-based alloys containing more than 1% of nitrogen. It was established that technology of mechanical alloying in ammonia atmosphere allows to prepare austenitic steels with nanocrystalline structure, which affords high value of yield stress. Physico-chemical patterns of interaction between the nitrogen-containing atmosphere and nitride-forming elements under their mutual mechanical activation conditions were established in consequence of theoretical and experimental researches. Some scientific principles of nanocrystalline materials were gained by quantitative description of correlation between the mechanical dose, nitrogen potential, nitrogen content in alloy and morphology of hardening phase.展开更多
The possibility of using of a pair of compression piston - cylinder with the unique performance features for the conversion of hydrocarbons are discusses. The experimental facility enables working in the pressure rang...The possibility of using of a pair of compression piston - cylinder with the unique performance features for the conversion of hydrocarbons are discusses. The experimental facility enables working in the pressure range that would be unattainable in diesel engines. The necessary degree of compression is managed and maintained by the computer system with a feedback.展开更多
Novel Ca_(8)CuRE(PO_(4))_(7)where RE^(3+)=Eu^(3+),Tb^(3+),Dy^(3+),Ho^(3+)and Er^(3+)were synthesized by a solid-state method in air.The structures of the samples were characterized by powder X-ray diffraction using Ri...Novel Ca_(8)CuRE(PO_(4))_(7)where RE^(3+)=Eu^(3+),Tb^(3+),Dy^(3+),Ho^(3+)and Er^(3+)were synthesized by a solid-state method in air.The structures of the samples were characterized by powder X-ray diffraction using Rietveld refinement to determine the occupation of crystal sites.The samples are found to have a centrosymmetric structure with space group R3c,as shown by dielectric measurements.These synthesized Ca_(8)CuRE(PO_(4))_(7)samples have multifunctional properties.The Cu^(2+)ions provide antibacterial properties,while the rare earth elements ions exhibit luminescence properties,and theβ-Ca_3(PO_(4))_(2)-type host is biocompatible.The photoluminescence properties of RE^(3+)ions were studied and compared with other simmilar Ca_(8)MRE(PO_(4))_(7)phosphates,where M is a divalent metal.The photoluminescence intensity quenching in terms of energy transfer from RE^(3+)to Cu^(2+)is disscused.The bioactive properties were studied in relation to antibacterial activity against E.coli and S.aureus.All syntesized Ca_(8)CuRE(PO_(4))_(7)samples demonstrate very high and stable inhibition of bacteria growth.The correlation between crystal structure and properties is discussed.By combining multiple approaches to the directio nal design of such materials,several important properties within a single chemical compound to achieve biovisualization and bioactive properties simultaneously can be combined.展开更多
The paper presents the results of the sterlet sturgeon Acipenser ruthenus reintroduction into the Kama Reservoir(Perm Krai,Russia)by sterlet fry from hatcheries into the reservoir since 2001.The effectiveness of hatch...The paper presents the results of the sterlet sturgeon Acipenser ruthenus reintroduction into the Kama Reservoir(Perm Krai,Russia)by sterlet fry from hatcheries into the reservoir since 2001.The effectiveness of hatchery releases was evaluated by monitoring gillnet sampling 2014-2020.The results showed that the species was reported throughout entire Kama Reservoir,which contrasts with 1988-1994 data,when the species was registered only at the upper part of the reservoir near the Kama River mouth.The highest number and biomass values of catch per unit effort(CPUE)of the sterlet were found in submerged river channels-the deepest habitats with flow conditions which are close to the ecological requirements of the species.The distribution of the sterlet within the channel biotopes of the reservoir is defined by reduced variability.The biggest individuals and the widest size range of the sterlet were typical for the upper area of the reservoir and Chusovskoy Bay,which have the greatest flow.The smallest sizes were typical for fish from catches near the dam of the reservoir,which is consistent with the published data on the distribution of sterlet in reservoir conditions.The presented results may indicate the artificial formation of the sterlet stock in the Kama Reservoir maintained by hatchery releases.The revealed distribution of the sterlet in the reservoir determines the direction of further research on natural reproduction and thus formation of an artificially formed population.Also,future studies are required to assess the possibility of hybridization of the sterlet of artificial origin with natural populations of the species,since the low genetic diversity of the sterlet released into the Kama Reservoir which can lead to irreversible loss of genetic individuality of the natural stocks of the species in the catchment of upper course of the Kama River.展开更多
We estimated the proportion of hatchery and natural fall spawning chum salmon returning to the Amur River using chemical markers specific to hatchery-origin fry.We used otolith microchemistry technique to identify fis...We estimated the proportion of hatchery and natural fall spawning chum salmon returning to the Amur River using chemical markers specific to hatchery-origin fry.We used otolith microchemistry technique to identify fish with artificial origin among returning spawners.First,we found that juveniles of artificial origin had higher values of the Sr:Ca molar ratio of the otoliths’edge zone compared with juveniles of natural origin,what can be related to the use of rearing feed produced from raw materials of marine origin rich in strontium.Then we observed that most of the spawners from Anyuisky Hatchery and from the Amur River mouth at the start of the spawning migration has also the higher value of Sr:Ca molar ratio of the juvenile zone of otoliths.Also,adults with higher values of the Sr:Ca molar ratio are characterized by a skewed right in the peak of the age distribution.Both,the age structure and phenological shift in the time of spawning migration of individuals with higher value of the used chemical marker corresponds to results of studies on hatchery-produced chum salmon completed at different parts on Northern Pacific.The results of this study will be used in the management of Amur fall chum salmon fisheries,and also demonstrates the necessity of the development of specific measures for increasing the survival of juvenile anadromous salmonids released at large rivers and exposed to prolonged freshwater migration to the ocean.As a further application of the methodology,we plan to identify the markers specific to each of the hatcheries and main spawning tributaries belonging to Amur River catchments.This will be an important step in the evaluation of the contribution of different stocks in mixed fisheries and also in the estimation of the effect of hatchery releases on naturally spawning stocks of Amur fall chum.Following to,our results may indicate the applicability of this approach for the determination of artificial-origin fish in a mixed sample of the Amur fall chum salmon.展开更多
This paper is an initial stage of consideration of the general problem of joint modeling of the vertical structure of a Galactic flat subsystem and the average surface of the disk of the Galaxy,taking into account the...This paper is an initial stage of consideration of the general problem of joint modeling of the vertical structure of a Galactic flat subsystem and the average surface of the disk of the Galaxy,taking into account the natural and measurement dispersions.We approximate the average surface of the Galactic disk in the region covered by the data with a general(polynomial)model and determine its parameters by minimizing the squared deviations of objects along the normal to the model surface.The smoothness of the model,i.e.,its order n,is optimized.An outlier elimination algorithm is applied.The developed method allows us to simultaneously identify significant details of the Galactic warping and estimate the offset z_(⊙) of the Sun relative to the average(in general,non-flat)surface of the Galactic disk and the vertical scale of the object system under consideration for an arbitrary area of the disk covered by data.The method is applied to data on classical Cepheids.Significant local extremes of the average disk surface model were found based on Cepheid data:the minimum in the first Galactic quadrant and the maximum in the second.A well-known warp(lowering of the disk surface)in the third quadrant has been confirmed.The optimal order of the model describing all these warping details was found to be n_(o)=4.The local(for a small neighborhood of the Sun,n_(o)=0)estimate of z_(⊙)=28.1±6.1|_(stat).±1.3|_(cal).pc is close to the non-local(taking into account warping,n_(o)=4)z_(⊙)=27.1±8.8|_(stat.-1.2)^(+1.3)|_(cal).pc(statistical and calibration uncertainties are indicated),which suggests that the proposed modeling method eliminates the influence of warping on the z_(⊙) estimate.However,the non-local estimate of the vertical standard deviation of Cepheids σ_(p)=132.0±3.7|_(stat.-5.9)^(+6.3)|_(cal).pc differs significantly from the local σ_(ρ)=76.5±4.4|_(stat.-3.4)^(+3.6)|_(cal).pc,which implies the need to introduce more complex models for the vertical distribution outside the Sun’s vicinity.展开更多
We investigated the dependence of the parameters of the segments of spiral arms of the Galaxy on the age of classical Cepheids.The catalog of Cepheids(Mel’nik et al.)was divided into two samples—relatively young(P&g...We investigated the dependence of the parameters of the segments of spiral arms of the Galaxy on the age of classical Cepheids.The catalog of Cepheids(Mel’nik et al.)was divided into two samples—relatively young(P>9d)and relatively old(P<9d)objects.The parameters of the spiral structure were determined both for two samples separately and jointly for the combination of two systems of segments traced by young and old objects.For most of the segments,their parameters for young and old objects differ significantly.Taking into account the difference between the two segment systems,we obtained the estimate R0 equal to 7.23^+0.19/-0.18 kpc,which in the modern Large Magellanic Cloud(LMC)calibration corresponds to the value of R0=8.08^+0.2/-10.20|stat.^+0.38/-0.36|cal.kpc.It is shown that the displacement between the segments is not reduced to the effect of differential rotation only.To interpret this displacement for objects of Perseus and Sagittarius-2 segments,we carried out a dynamic modeling of the change in the position of the segment points when moving in the smooth gravitational field of the Galaxy.At the angular velocity of rotation of the spiral pattern Ωp=25.2±0.5 km s 1 kpc 1(Dambis et al.)the observed displacement between segments on young and old objects can be explained by the amplitude of spiral perturbations of the radial velocity of u=10±1.5 km s 1.For the constructed double system of spiral segments,it is demonstrated that the assumption of constancy of the pitch angles within each segment and the assumption that the pole of the spiral pattern is in the direction of the nominal center of the Galaxy do not contradict the data within the range of uncertainty.展开更多
The modern accuracy of measurements allows the residual/peculiar(Galactocentric) velocity of the supermassive black hole(SMBH) in our Galaxy, Sgr A*, on the order of several kilometers per second.We integrate possible...The modern accuracy of measurements allows the residual/peculiar(Galactocentric) velocity of the supermassive black hole(SMBH) in our Galaxy, Sgr A*, on the order of several kilometers per second.We integrate possible orbits of the SMBH along with the surrounding nuclear stellar cluster(NSC) for a barred model of the Galaxy using modern constraints on the components of the SMBH Galactocentric velocity. Is is shown that the range of oscillations of the SMBH + NSC in a regular Galactic field in the plane of the Galaxy allowed by these constraints strongly depends on the set of central components of the Galactic potential. If the central components are represented only by a bulge/bar, for a point estimate of the SMBH Galactocentric velocity, the oscillation amplitude does not exceed 7 pc in the case that a classical bulge is present and reaches 25 pc if there is no bulge;with SMBH velocity components within the 2σ significance level, the amplitude can reach 15 and 50 pc, respectively. However, when taking into account the nuclear stellar disk(NSD), even in the absence of a bulge, the oscillation amplitude is only 5 pc for the point estimate of the SMBH velocity, and 10 pc for the 2σ significance level. Thus, the possible oscillations of the SMBH + NSC complex from the confirmed components of the Galaxy’s potential are mostly limited by the NSD, and even taking into account the uncertainty of the mass of the latter, the oscillation amplitude can hardly exceed 13 pc = 6′.展开更多
文摘This paper details the development and testing of the first working prototype of the S-band high-power klystron,accomplished at the Budker Institute of Nuclear Physics,Siberian Branch,Russian Academy of Sciences(BINP SB RAS).Upon testing,the klystron demonstrated the following parameters:an operating frequency of 2856 MHz and a peak power output of 50 MW.The paper presents the klystron's design,its constituent units,and pertinent processing procedures,along with discussions on the measurement of its parameters.
基金China Scholarship Council,Grant/Award Number:202007090144National Natural Science Foundation of China,Grant/Award Number:51577011Fundamental Research Funds for the Central Universities,Grant/Award Number:2018YJS162。
文摘An innovative double-ejection micro-cathode arc thruster(AC_(d-μ)CAT),which consists of a cylindrical inner anode,a cylindrical outer cathode and two insulating sleeves(an inner insulating sleeve and an outer insulating sleeve),was proposed.The differences in electrical characteristics,plasma parameters and propulsion performance between the newly proposed AC_(d-μ)CAT and a traditionalμCAT were examined.Study results showed that compared to the traditionalμCAT structure,by using the AC_(d-μ)CAT,the peak value of produced thrust was increased 9.3 times,while the amplitude of the ion current and the ion-to-arc ratio were increased 5.4 and 5.9 times(from 1.2%to 7.1%),respectively.In addition,data from Langmuir probe experiments indicated that peak values of the directional propagation speed and density of plasma plume were increased 3.1 times and 4.2 times,respectively.Moreover,plasma plume directional ejection performance was also significantly improved.This study result will provide support for the development of a new-generationμCAT.
基金financially supported by the National Natural Science Foundation of China(No.51302061)the Natural Science Foundation of Hebei province(Nos.E2014201076,E2020201021 and E2023201019)+3 种基金the Research Innovation Team of College of Chemistry and Environmental Science of Hebei University(No.hxkytd2102)Shenzhen Science and Technology Innovation Committee(No.JCYJ20200109141412308)Bintuan Science and Technology Program(Nos.2020DB002 and 2022DB009)CWO funding of Ghent University。
文摘One key strategy to enhance photocatalytic performance is to improve the transfer and separation efficiency of photogenerated carriers by building optimized heterojunctions.Herein,novel Bi_(4)O_5Br_(2)/NH_(2)-MIL-125(Ti)Z-scheme heterojunctions are fabricated and used as photocatalysts for organic pollutant photodegradation.The NH_(2)-MIL-125(Ti)nanosheets are exfoliated via a self-developed alkali solution stripping approach and then uniformly decorated on Bi_(4)O_(5)Br_(2).The as-prepared Bi_(4)O_(5)Br_(2)/NH_(2)-MIL-125(Ti)presents more than 90%degradation of various pollutants,outperforming the counterpart individual ones.The various characterization results suggest that the enhanced degradation rate is due to the more intimate face-to-face interfacial contact of the lamellar Z-scheme heterojunction materials,in which the migration path of carriers from the material's interior to the surface can be reduced,in turn enhancing migration efficiency and separation capability significantly.A possible photocatalytic reaction mechanism is proposed based on the photoelectric behaviors,radical trapping experiments and liquid chromatography mass spectrometry analysis.This work promotes the development of new photocatalytic materials for heterojunctions with face-to-face interfacial contacts,as well as the effective purification of wastewater in environmental remediation.
文摘BACKGROUND Lower gastrointestinal bleeds(LGIB)is a very common inpatient condition in the United States.Gastrointestinal bleeds have a variety of presentations,from minor bleeding to severe hemorrhage and shock.Although previous studies investigated the efficacy of colonoscopy in hospitalized patients with LGIB,there is limited research that discusses disparities in colonoscopy utilization in patients with LGIB in urban and rural settings.AIM To investigate the difference in utilization of colonoscopy in lower gastrointestinal bleeding between patients hospitalized in urban and rural hospitals.METHODS This is a retrospective cohort study of 157748 patients using National Inpatient Sample data and the Healthcare Cost and Utilization Project provided by the Agency for Healthcare Research and Quality.It includes patients 18 years and older hospitalized with LGIB admitted between 2010 and 2016.This study does not differentiate between acute and chronic LGIB and both are included in this study.The primary outcome measure of this study was the utilization of colonoscopy among patients in rural and urban hospitals admitted for lower gastrointestinal bleeds;the secondary outcome measures were in-hospital mortality,length of stay,and costs involved in those receiving colonoscopy for LGIB.Statistical analyses were all performed using STATA software.Logistic regression was used to analyze the utilization of colonoscopy and mortality,and a generalized linear model was used to analyze the length of stay and cost.RESULTS Our study found that 37.9%of LGIB patients at rural hospitals compared to approximately 45.1%at urban hospitals received colonoscopy,(OR=0.730,95%CI:0.705-0.7,P>0.0001).After controlling for covariates,colonoscopies were found to have a protective association with lower inhospital mortality[OR=0.498,95%CI:0.446-0.557,P<0.0001],but a longer length of stay by 0.72 d(95%CI:0.677-0.759 d,P<0.0001)and approximately$2199 in increased costs.CONCLUSION Although there was a lower percentage of LGIB patients that receiv
基金supported by the National Key Research and Development Program of China(2017YFD0200204)the National Natural Science Foundation of China(31972496,31572190)+1 种基金the Deutsche Forschungsgemeinschaft(328017493/GRK2366)the National Institutes of Health Grant(R15 GM 104876)to Jana Patton-Vogt。
文摘Phosphate deficiency is one of the leading causes of crop productivity loss.Phospholipid degradation liberates phosphate to cope with phosphate deficiency.Glycerophosphodiester phosphodiesterases(GPX-PDEs)hydrolyse the intermediate products of phospholipid catabolism glycerophosphodiesters into glycerol-3-phosphate,a precursor of phosphate.However,the function of GPX-PDEs in phosphate remobilization in maize remains unclear.In the present study,we characterized two phosphate deficiency-inducible GPX-PDE genes,ZmGPX-PDE1 and ZmGPX-PDE5,in maize leaves.ZmGPX-PDE1 and ZmGPX-PDE5 were transcriptionally regulated by ZmPHR1,a well-described phosphate starvation-responsive transcription factor of the MYB family.Complementation of the yeast GPX-PDE mutant gde1Δindicated that ZmGPX-PDE1 and ZmGPX-PDE5 functioned as GPX-PDEs,suggesting their roles in phosphate recycling from glycerophosphodiesters.In vitro enzyme assays showed that ZmGPX-PDE1 and ZmGPX-PDE5 catalysed glycerophosphodiester degradation with different substrate preferences for glycerophosphoinositol and glycerophosphocholine,respectively.ZmGPX-PDE1 was upregulated during leaf senescence,and more remarkably,loss of ZmGPXPDE1 inmaize compromised the remobilization of phosphorus fromsenescing leaves to young leaves,resulting in a stay-green phenotype under phosphate starvation.These results suggest that ZmGPX-PDE1 catalyses the degradation of glycerophosphodiesters in maize,promoting phosphate recycling from senescing leaves to new leaves.This mechanism is crucial for improving phosphorus utilization efficiency in crops.
基金Supported by the Russian Science Foundation,No.22-25-00484。
文摘BACKGROUND Necrotizing enterocolitis(NEC)is a multifactorial disease that predominantly affects premature neonates.Intestinal dysbiosis plays a critical role in NEC pathogenesis in premature neonates.The main risk factor for NEC in term infants is mesenteric hypoperfusion associated with ductaldependent congenital heart disease(CHD)that eventually leads to intestinal ischemia.The incidence of NEC in neonates with critical CHD is 6.8%-13%.However,the role of the intestinal microbiome in NEC pathogenesis in infants with ductal-dependent CHD remains unclear.CASE SUMMARY A male term neonate with right atrial isomerism underwent modified Blalock-Taussig shunt placement on the 14^(th)day of life and had persistent mesenteric hypoperfusion after surgery.The patient had episodes of NEC stageⅡA on the 1^(st)and 28^(th)days after cardiac surgery.Fecal microbial composition was analyzed before and after cardiac surgery by sequencing region V4 of the 16S rRNA gene.Before surgery,species belonging to genera Veillonella and Clostridia and class Gammaproteobacteria were detected,Bifidobacteriaceae showed a low abundance.The first NEC episode was associated with postoperative hemodynamic instability,intestinal ischemiareperfusion injury during cardiopulmonary bypass,and a high abundance of Clostridium paraputrificum(Clostridium sensu stricto I)(56.1%).Antibacterial therapy after the first NEC episode resulted in increased abundance of Gammaproteobacteria,decreased abundance of Firmicutes,and low alpha diversity.These changes in the microbial composition promoted the growth of Clostridium sensu strictoⅠ(72.0%)before the second NEC episode.CONCLUSION A high abundance of Clostridium sensu strictoⅠand mesenteric hypoperfusion may have contributed to NEC in the present case.
基金This work is finically supported by the National Key R&D Program of China(Grant No.2017YFE0120500)the National Natural Science Foundation of China(Grant Nos.51972129,21725102)+3 种基金the Bintuan Science and Technology Program(Grant Nos.2020DB002,2022DB009)the Key Research and Development Program of Hubei(Grant No.2020BAB079)the Science and Technology Innovation Committee Foundation of Shenzhen(Grant No.JCYJ20210324141613032)the Natural Science Foundation of Jiangsu Province of China(BK20211609).
文摘Electrocatalytic urea oxidation reaction(UOR)is regarded as an effective yet challenging approach for the degradation of urea in wastewater into harmless N2 and CO_(2).To overcome the sluggish kinetics,catalytically active sites should be rationally designed to maneuver the multiple key steps of intermediate adsorption and desorption.Herein,we demonstrate that metal-organic frameworks(MOFs)can provide an ideal platform for tailoring binary active sites to facilitate the rate-determining steps,achieving remarkable electrocatalytic activity toward UOR.Specifically,the MOF(namely,NiMn_(0.14)-BDC)based on Ni/Mn sites and terephthalic acid(BDC)ligands exhibits a low voltage of 1.317 V to deliver a current density of 10 mA cm^(-2).As a result,a high turnover frequency(TOF)of 0.15 s^(-1) is achieved at a voltage of 1.4 V,which enables a urea degradation rate of 81.87%in 0.33 M urea solution.The combination of experimental characterization with theoretical calculation reveals that the Ni and Mn sites play synergistic roles in maneuvering the evolution of urea molecules and key reaction intermediates during the UOR,while the binary Ni/Mn sites in MOF offer the tunability for electronic structure and d-band center impacting on the intermediate evolution.This work provides important insights into active site design by leveraging MOF platform and represents a solid step toward highly efficient UOR with MOF-based electrocatalysts.
文摘Accurate diagnosis of different bronchopul- monary diseases is important in clinical practice. This study involved 20 healthy volunteers and 77 patients with bronchopulmonary diseases, including chronic obstructive pulmonary disease （COPD）, bronchial asthma, pulmonary tuberculosis, and community-acquired pneumonia. The absorption spectrum of exhaled air samples was recorded on an intra-cavity photo-acoustic gas analyzer （ILPA-1, Special Technologies, Ltd., Russia） with photo-acoustic detectors and CO2 laser with a tuning range from 9.2 to 10.8μm. In conclusion, analysis of the Mahalanobis distance-based absorption spectral profiles of breath air from bronchopulmonary patients and healthy volunteers allows the formulation of a preliminary diagnosis.
文摘Results of investigations of band structure, Fermi surface and effective masses of charge carriers in the ultrathin (monolayer graphene)/MnO(001) and MnO(001) films are presented using the method of the density functional theory. Features of spin states of valence band and Fermi level as well as an interatomic interaction in these systems are discussed. A magnetic moment at Mn atom is estimated and an effect of spin polarization at atoms of oxygen and carbon has been revealed which natures are discussed. By calculations of structural energies for 2D (monolayer graphene)/MnO(001) and 2D MnO(001) a stability of these systems has been ascertained. In the 2D (monolayer graphene)/MnO(001) and 2D MnO(001) systems the band structure calculations for the 2D systems mentioned above point out that tensor components of effective masses of both electrons and holes are in the ranges of (0.15 - 0.54) m0 and (0.38 - 1.27) m0 respectively. Mobility estimations of two-dimensional charge carriers for a 2D (monolayer graphene)/MnO(001)AF2 heterostructure have been performed.
文摘In this paper, developed wireless portable infrared pyrometer with dual channel fiber optic is described. The pyrometer measures surface temperature in wide infrared spectral range of 2 - 25 um. A data processing algorithm based on the methods of synchronous detection providing
文摘Iron-based products account the main volume of powder metallurgy production. Nevertheless its strength and reliability are not enough in comparison with classical cast materials. So that is why making nanostructural powder materials allows to increase strength and extend the range of products. A principally new way of nanostructure production is possible by means of iron mechanical alloying with nitride-forming and nitrogen both at the same time. Unlike classical technology of internal nitrogenation, nitrogen saturation, in our case, occurs by whole volume at plastic deformation conditions. A review of experimental results of phase forming alloys in the Fe-Ni, Fe-Ni-Cr, Fe-Ni-N, Fe-Ni-Cr-N, Fe-Cr-Ni systems prepared by mechanical alloying are given. The influence of the technological parameters of mechanical alloying, atmosphere of mechanical activation on nitrogen content and phase composition of examined alloys has been studied. Experimental results of the influence of mechanical alloying technological parameters on degree of ammonia dissociation and nitrogen content in examined alloys are presented. Heat treatment influence of mechanically alloyed, nitrogen-containing alloys on their phase composition and structure are investigated. It was shown that using mechanical alloying, it’s possible to prepare high-alloyed iron-based alloys containing more than 1% of nitrogen. It was established that technology of mechanical alloying in ammonia atmosphere allows to prepare austenitic steels with nanocrystalline structure, which affords high value of yield stress. Physico-chemical patterns of interaction between the nitrogen-containing atmosphere and nitride-forming elements under their mutual mechanical activation conditions were established in consequence of theoretical and experimental researches. Some scientific principles of nanocrystalline materials were gained by quantitative description of correlation between the mechanical dose, nitrogen potential, nitrogen content in alloy and morphology of hardening phase.
文摘The possibility of using of a pair of compression piston - cylinder with the unique performance features for the conversion of hydrocarbons are discusses. The experimental facility enables working in the pressure range that would be unattainable in diesel engines. The necessary degree of compression is managed and maintained by the computer system with a feedback.
基金Project supported by Russian Science Foundation(19-77-10013-Ⅱ)。
文摘Novel Ca_(8)CuRE(PO_(4))_(7)where RE^(3+)=Eu^(3+),Tb^(3+),Dy^(3+),Ho^(3+)and Er^(3+)were synthesized by a solid-state method in air.The structures of the samples were characterized by powder X-ray diffraction using Rietveld refinement to determine the occupation of crystal sites.The samples are found to have a centrosymmetric structure with space group R3c,as shown by dielectric measurements.These synthesized Ca_(8)CuRE(PO_(4))_(7)samples have multifunctional properties.The Cu^(2+)ions provide antibacterial properties,while the rare earth elements ions exhibit luminescence properties,and theβ-Ca_3(PO_(4))_(2)-type host is biocompatible.The photoluminescence properties of RE^(3+)ions were studied and compared with other simmilar Ca_(8)MRE(PO_(4))_(7)phosphates,where M is a divalent metal.The photoluminescence intensity quenching in terms of energy transfer from RE^(3+)to Cu^(2+)is disscused.The bioactive properties were studied in relation to antibacterial activity against E.coli and S.aureus.All syntesized Ca_(8)CuRE(PO_(4))_(7)samples demonstrate very high and stable inhibition of bacteria growth.The correlation between crystal structure and properties is discussed.By combining multiple approaches to the directio nal design of such materials,several important properties within a single chemical compound to achieve biovisualization and bioactive properties simultaneously can be combined.
文摘The paper presents the results of the sterlet sturgeon Acipenser ruthenus reintroduction into the Kama Reservoir(Perm Krai,Russia)by sterlet fry from hatcheries into the reservoir since 2001.The effectiveness of hatchery releases was evaluated by monitoring gillnet sampling 2014-2020.The results showed that the species was reported throughout entire Kama Reservoir,which contrasts with 1988-1994 data,when the species was registered only at the upper part of the reservoir near the Kama River mouth.The highest number and biomass values of catch per unit effort(CPUE)of the sterlet were found in submerged river channels-the deepest habitats with flow conditions which are close to the ecological requirements of the species.The distribution of the sterlet within the channel biotopes of the reservoir is defined by reduced variability.The biggest individuals and the widest size range of the sterlet were typical for the upper area of the reservoir and Chusovskoy Bay,which have the greatest flow.The smallest sizes were typical for fish from catches near the dam of the reservoir,which is consistent with the published data on the distribution of sterlet in reservoir conditions.The presented results may indicate the artificial formation of the sterlet stock in the Kama Reservoir maintained by hatchery releases.The revealed distribution of the sterlet in the reservoir determines the direction of further research on natural reproduction and thus formation of an artificially formed population.Also,future studies are required to assess the possibility of hybridization of the sterlet of artificial origin with natural populations of the species,since the low genetic diversity of the sterlet released into the Kama Reservoir which can lead to irreversible loss of genetic individuality of the natural stocks of the species in the catchment of upper course of the Kama River.
基金support of the grant of the Ministry of Science and Higher Education of the Russian Federation project No.2019-0858"Biogeochemical and geochemical studies of landscapes in the conditions of the development of mineral deposits,the search for new methods of monitoring and forecasting the State of the environment".
文摘We estimated the proportion of hatchery and natural fall spawning chum salmon returning to the Amur River using chemical markers specific to hatchery-origin fry.We used otolith microchemistry technique to identify fish with artificial origin among returning spawners.First,we found that juveniles of artificial origin had higher values of the Sr:Ca molar ratio of the otoliths’edge zone compared with juveniles of natural origin,what can be related to the use of rearing feed produced from raw materials of marine origin rich in strontium.Then we observed that most of the spawners from Anyuisky Hatchery and from the Amur River mouth at the start of the spawning migration has also the higher value of Sr:Ca molar ratio of the juvenile zone of otoliths.Also,adults with higher values of the Sr:Ca molar ratio are characterized by a skewed right in the peak of the age distribution.Both,the age structure and phenological shift in the time of spawning migration of individuals with higher value of the used chemical marker corresponds to results of studies on hatchery-produced chum salmon completed at different parts on Northern Pacific.The results of this study will be used in the management of Amur fall chum salmon fisheries,and also demonstrates the necessity of the development of specific measures for increasing the survival of juvenile anadromous salmonids released at large rivers and exposed to prolonged freshwater migration to the ocean.As a further application of the methodology,we plan to identify the markers specific to each of the hatcheries and main spawning tributaries belonging to Amur River catchments.This will be an important step in the evaluation of the contribution of different stocks in mixed fisheries and also in the estimation of the effect of hatchery releases on naturally spawning stocks of Amur fall chum.Following to,our results may indicate the applicability of this approach for the determination of artificial-origin fish in a mixed sample of the Amur fall chum salmon.
文摘This paper is an initial stage of consideration of the general problem of joint modeling of the vertical structure of a Galactic flat subsystem and the average surface of the disk of the Galaxy,taking into account the natural and measurement dispersions.We approximate the average surface of the Galactic disk in the region covered by the data with a general(polynomial)model and determine its parameters by minimizing the squared deviations of objects along the normal to the model surface.The smoothness of the model,i.e.,its order n,is optimized.An outlier elimination algorithm is applied.The developed method allows us to simultaneously identify significant details of the Galactic warping and estimate the offset z_(⊙) of the Sun relative to the average(in general,non-flat)surface of the Galactic disk and the vertical scale of the object system under consideration for an arbitrary area of the disk covered by data.The method is applied to data on classical Cepheids.Significant local extremes of the average disk surface model were found based on Cepheid data:the minimum in the first Galactic quadrant and the maximum in the second.A well-known warp(lowering of the disk surface)in the third quadrant has been confirmed.The optimal order of the model describing all these warping details was found to be n_(o)=4.The local(for a small neighborhood of the Sun,n_(o)=0)estimate of z_(⊙)=28.1±6.1|_(stat).±1.3|_(cal).pc is close to the non-local(taking into account warping,n_(o)=4)z_(⊙)=27.1±8.8|_(stat.-1.2)^(+1.3)|_(cal).pc(statistical and calibration uncertainties are indicated),which suggests that the proposed modeling method eliminates the influence of warping on the z_(⊙) estimate.However,the non-local estimate of the vertical standard deviation of Cepheids σ_(p)=132.0±3.7|_(stat.-5.9)^(+6.3)|_(cal).pc differs significantly from the local σ_(ρ)=76.5±4.4|_(stat.-3.4)^(+3.6)|_(cal).pc,which implies the need to introduce more complex models for the vertical distribution outside the Sun’s vicinity.
基金support from the Russian Science Foundation,Grant No.18-12-00050。
文摘We investigated the dependence of the parameters of the segments of spiral arms of the Galaxy on the age of classical Cepheids.The catalog of Cepheids(Mel’nik et al.)was divided into two samples—relatively young(P>9d)and relatively old(P<9d)objects.The parameters of the spiral structure were determined both for two samples separately and jointly for the combination of two systems of segments traced by young and old objects.For most of the segments,their parameters for young and old objects differ significantly.Taking into account the difference between the two segment systems,we obtained the estimate R0 equal to 7.23^+0.19/-0.18 kpc,which in the modern Large Magellanic Cloud(LMC)calibration corresponds to the value of R0=8.08^+0.2/-10.20|stat.^+0.38/-0.36|cal.kpc.It is shown that the displacement between the segments is not reduced to the effect of differential rotation only.To interpret this displacement for objects of Perseus and Sagittarius-2 segments,we carried out a dynamic modeling of the change in the position of the segment points when moving in the smooth gravitational field of the Galaxy.At the angular velocity of rotation of the spiral pattern Ωp=25.2±0.5 km s 1 kpc 1(Dambis et al.)the observed displacement between segments on young and old objects can be explained by the amplitude of spiral perturbations of the radial velocity of u=10±1.5 km s 1.For the constructed double system of spiral segments,it is demonstrated that the assumption of constancy of the pitch angles within each segment and the assumption that the pole of the spiral pattern is in the direction of the nominal center of the Galaxy do not contradict the data within the range of uncertainty.
基金support from the Russian Foundation for Basic Research,Grant No.18-0200552。
文摘The modern accuracy of measurements allows the residual/peculiar(Galactocentric) velocity of the supermassive black hole(SMBH) in our Galaxy, Sgr A*, on the order of several kilometers per second.We integrate possible orbits of the SMBH along with the surrounding nuclear stellar cluster(NSC) for a barred model of the Galaxy using modern constraints on the components of the SMBH Galactocentric velocity. Is is shown that the range of oscillations of the SMBH + NSC in a regular Galactic field in the plane of the Galaxy allowed by these constraints strongly depends on the set of central components of the Galactic potential. If the central components are represented only by a bulge/bar, for a point estimate of the SMBH Galactocentric velocity, the oscillation amplitude does not exceed 7 pc in the case that a classical bulge is present and reaches 25 pc if there is no bulge;with SMBH velocity components within the 2σ significance level, the amplitude can reach 15 and 50 pc, respectively. However, when taking into account the nuclear stellar disk(NSD), even in the absence of a bulge, the oscillation amplitude is only 5 pc for the point estimate of the SMBH velocity, and 10 pc for the 2σ significance level. Thus, the possible oscillations of the SMBH + NSC complex from the confirmed components of the Galaxy’s potential are mostly limited by the NSD, and even taking into account the uncertainty of the mass of the latter, the oscillation amplitude can hardly exceed 13 pc = 6′.
