Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tec...Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tectonic settings in the period of basin deposition. Results of geochemical analyses in this paper show that sandstone samples of the Mesozoic Mohe basin fall in active continental margin settings on several kinds of tectonic discriminatory diagrams (Bhatia et al. 1983, 1986; Roser et al. 1986,1988,1999). The samples are also characterized by binary-system provenances, whose terrigenous clastic materials mainly derived from the oro- genic belt near the basin to the north and secondarily from the continental region in the south of the basin at the same time. The research results of rock geochemistry, combined with tectonic analysis, reflect that tectonic type of the basin is a foreland basin with nature of depositional ac- cumulation of molass, but not continental rift basin considered in the past. This finding provides important evidence of rock geochemistry for the original structural linkage between the Mohe Foreland Basin and Mongol-Okhotsk Orogen in Mesozoic.展开更多
We aim to evaluate the incidence of incontinence following laser endoscopic enucleation of the prostate(EEP)comparing en-bloc(Group 1)versus 2-lobe/3-lobe techniques(Group 2).We performed a retrospective review of pat...We aim to evaluate the incidence of incontinence following laser endoscopic enucleation of the prostate(EEP)comparing en-bloc(Group 1)versus 2-lobe/3-lobe techniques(Group 2).We performed a retrospective review of patients undergoing EEP for benign prostaticenlargement in 12 centers between January 2020 and January 2022.Data were presented as median and interquartile range(IQR).Univariable and multivariable logistic regression analysis was performed to evaluate factors associated with stress urinary incontinence(SUI)and mixed urinary incontinence(MUI).There were 1711 patients in Group 1 and 3357 patients in Group 2.Patients in Group 2were significantly younger(68[62–73]years vs 69[63–74]years,P=0.002).Median(interquartile range)prostate volume(PV)wassimilar between the groups(70[52–92]ml in Group 1 vs 70[54–90]ml in Group 2,P=0.774).There was no difference in preoperativeInternational Prostate Symptom Score,quality of life,or maximum flow rate.Enucleation,morcellation,and total surgical time weresignificantly shorter in Group 1.Within 1 month,overall incontinence rate was 6.3%in Group 1 versus 5.3%in Group 2(P=0.12),and urge incontinence was significantly higher in Group 1(55.1%vs 37.3%in Group 2,P<0.001).After 3 months,the overall rate ofincontinence was 1.7%in Group 1 versus 2.3%in Group 2(P=0.06),and SUI was significantly higher in Group 2(55.6%vs 24.1%in Group 1,P=0.002).At multivariable analysis,PV and IPSS were factors significantly associated with higher odds of transient SUI/MUI.PV,surgical time,and no early apical release technique were factors associated with higher odds of persistent SUI/MUI.展开更多
In this review,we tried to systematize all the evidence(from PubMed[MEDLINE],Scopus,Cochrane Library,EBSCO,Embase,and Google Scholar)from 1993 to 2021 on the predictors of microsurgical varicocelectomy efficacy in mal...In this review,we tried to systematize all the evidence(from PubMed[MEDLINE],Scopus,Cochrane Library,EBSCO,Embase,and Google Scholar)from 1993 to 2021 on the predictors of microsurgical varicocelectomy efficacy in male infertility treatment.Regarding the outcomes of varicocele repair,we considered semen improvement and pregnancy and analyzed them separately.Based on the 2011 Oxford CEBM Levels of Evidence,we assigned a score to each trial that studied the role of the predictor.We systematized the studied predictors based on the total points,which were,in turn,calculated based on the number and quality of studies that confirmed or rejected the studied predictor as significant,into three levels of significance:predictors of high,moderate,and low clinical significance.Preoperative total motile sperm count(TMSC)coupled with sperm concentration can be a significant predictor of semen improvement and pregnancy after varicocelectomy.In addition,for semen improvement alone,scrotal Doppler ultrasound(DUS)parameters,sperm DNA fragmentation index(DFI),and bilateral varicocelectomy are reliable predictors of microsurgical varicocelectomy efficacy.展开更多
The development of positive and negative streamers in a point-to-plane gap filled with air and nitrogen at various pressures(50-200 kPa)and voltages(8-25 kV)was studied.A four-channel intensified charge-coupled device...The development of positive and negative streamers in a point-to-plane gap filled with air and nitrogen at various pressures(50-200 kPa)and voltages(8-25 kV)was studied.A four-channel intensified charge-coupled device(ICCD)and a streak-camera were used.Electrical parameters were measured with high resolution(10 GHz).An original method of measuring a displacement current caused by a streamer was applied.As was expected,positive streamer branches in nitrogen at low voltages and/or elevated pressures while a large-diameter streamer is formed in air.However,at high voltages or negative polarity,the large-diameter streamer is formed both in nitrogen and air in the entire pressure range.It was found that runaway electrons(REs)are generated in the very first picoseconds of gas ionisation near the pointed cathode.It was assumed that REs can be generated near the pointed anode and produce bremsstrahlung radiation due to a sharply inhomogeneous distribution of electrical potential.It was found that in the final stage of negative streamer development in air and nitrogen,the gas between the streamer front and the opposite electrode is ionised almost simultaneously in the entire volume when the streamer diameter is almost equal to the interelectrode gap.展开更多
The prevalence of nephrolithiasis is increasing worldwide.Understanding and implementing medical therapies for kidney stone prevention are critical to prevent recurrences and decrease the economic burden of this condi...The prevalence of nephrolithiasis is increasing worldwide.Understanding and implementing medical therapies for kidney stone prevention are critical to prevent recurrences and decrease the economic burden of this condition.Dietary and pharmacologic therapies require understanding on the part of the patient and the prescribing practitioner in order to promote compliance.Insights into occupational exposures and antibiotic use may help uncover individual risk factors.Follow-up is essential to assess response to treatment and to modify treatment plans to maximize therapeutic benefit.展开更多
The synthesis of nanopowders of terbia compounds with scandia, yttria, and lutetia was carried out using a self-propagating high-temperature synthesis method involving a mixture of nitrates of metals and glycine as a ...The synthesis of nanopowders of terbia compounds with scandia, yttria, and lutetia was carried out using a self-propagating high-temperature synthesis method involving a mixture of nitrates of metals and glycine as a precursor. The nanopowder phase transformations were investigated using X-ray diffraction analysis. It was found that lutetia has a negligible effect on the phase formation in terbia. On the other hand, yttrium and scandium ions significantly suppressed crystallization. The densification kinetics of nanopowders of the Tb_2O_3 compounds and the microstructure of ceramics after microwave sintering were studied using dilatometry and scanning electron microscopy. The introduction of scandia, yttria, or lutetia contributed to the intensification of the densification of the terbia ceramics when heated in a microwave field. Near full-density materials of terbia solid solutions with lutetia and yttria were obtained at about 1600–1640 ℃. The ceramics of scandia–terbia compounds contained the second phase, which causes light scattering.展开更多
INTRODUCTION The saiga antelope[Saiga tatarica(Linnaeus,1766)]is an extant representative of the large herbivorous mammals’complex of Pleistocene steppe-tundra ecosystem(Bannikov et al.1961;Baryshnikov et al.1998).In...INTRODUCTION The saiga antelope[Saiga tatarica(Linnaeus,1766)]is an extant representative of the large herbivorous mammals’complex of Pleistocene steppe-tundra ecosystem(Bannikov et al.1961;Baryshnikov et al.1998).In the course of its evolutionary history,under the influence of global climate changes and later anthropogenic factors,the species experienced multiple changes in number and range.During the last Ice Age,the saiga range in Eurasia was integral and achieved its maximum in the entire species history:In the west,it reached the Pyrenees and the Alps,and in the east inhabited Yakutia and Chukotka(Kahlke 2014).The disintegration of the range is directly related and correlates well with the destruction of tundra ecosystems(Baryshnikov et al.1998).Currently,there are two subspecies of the saiga:the Mongolian saiga,S.t.mongolica(=S.borealis),and nominative subspecies,S.t.tatarica.The Mongolian subspecies is represented by a single saiga population in Mongolia.There are four populations of the nominative subspecies in the arid ecosystems of Kazakhstan(Ural,Betpakdala,Ustyurt populations)and Russia(Northwest Pre-Caspian population).展开更多
In this paper,we discuss the properties of ionization waves(IWs)in a multi-pulsed plasma jet while using the two-dimensional computational approach.The IWs are generated by application of three short negative pulses w...In this paper,we discuss the properties of ionization waves(IWs)in a multi-pulsed plasma jet while using the two-dimensional computational approach.The IWs are generated by application of three short negative pulses with a repetition frequency 12.5 MHz.The simulations are performed continuously during a single run while accounting for charges accumulated inside(surface charges)and outside(space charges)the tube.The plasma forming gas mixture(He/O2=99.8%/0.2%)is injected through the discharge tube into the surrounding humid air.We show that an IW can emerge from the tube exit at a pulse rising edge(as a negative IW)and at a falling edge of the same pulse(as a positive IW).It is demonstrated that remnants of the negative and positive charges play an essential role in the discharge evolution.The first pulse travels the shortest distance as it propagates through the initially non-ionized environment.The IWs developing during the second pulse essentially enlarge the plasma plume length.At the same time,the IWs generated by the third pulse eventually decay due to the remnants of charges accumulated during the previous pulses.Accumulated memory charges can lead to the IW extinction.展开更多
To better understand the spatial structure of Amur tigers(Panthera tigris altaica)at the southern edge of their range we fitted 14 tigers(6♀♀and 8♂♂)with 15 GPS-Argos collars between 2008 and 2011 in 2 study sites...To better understand the spatial structure of Amur tigers(Panthera tigris altaica)at the southern edge of their range we fitted 14 tigers(6♀♀and 8♂♂)with 15 GPS-Argos collars between 2008 and 2011 in 2 study sites:the Ussuriskii Reserve of southern Sikhote-Alin and the Land of the Leopard National Park in southwest Primorye,Russian Far East.Fixed kernel estimates of male home ranges were larger than those of female home ranges(P<0.05[mean 95%fixed kernel♀=401±205 km2;mean 95%fixed kernel♂=778±267 km2]).The home range size of females varied greatly,but on average was similar to estimates derived from earlier work further north.Low overlap of adjacent home ranges suggested that females retained exclusive territories.Real core areas of females overlapped only slightly,and remained stable over multiple years.The home ranges of adult males were smaller than those of males to the north,and in contrast to previous studies,high overlap among males indicated the absence of territoriality.Nonetheless,real core areas of males did not overlap,suggesting some spatial separation.In comparison to other tiger populations and other areas of the Russian Far East,the sex ratio in our 2 study areas was highly skewed towards males.We believe this skewed sex ratio resulted in the dissolution of territoriality of males due to an inability to defend individual females,with males resorting to scramble competition for mates.Continued monitoring of these sites to determine whether shifts in the sex ratio might result in a return to male territoriality would provide confirmation of our tentative hypothesis.展开更多
Forecasting crop yields based on remote sensing data is one of the most important tasks in agriculture.Soybean is the main crop in the Russian Far East.It is desirable to forecast soybean yield as early as possible wh...Forecasting crop yields based on remote sensing data is one of the most important tasks in agriculture.Soybean is the main crop in the Russian Far East.It is desirable to forecast soybean yield as early as possible while maintaining high accuracy.This study aimed to investigate seasonal time series of the normalized difference vegetation index(NDVI) to achieve early forecasting of soybean yield.This research used data from the Moderate Resolution Image Spectroradiometer(MODIS),an arable-land mask obtained from the VEGA-Science web service,and soybean yield data for 2008-2017 for the Jewish Autonomous Region(JAR) districts.Four approximating functions were fitted to model the NDVI time series:Gaussian,double logistic(DL),and quadratic and cubic polynomials.In the period from calendar weeks 22-42(end of May to mid-October),averaged over two districts,the model using the DL function showed the highest accuracy(mean absolute percentage error-4.0%,root mean square error(RMSE)-0.029,P <0.01).The yield forecast accuracy of prediction in the period of weeks 25-30 in JAR municipalities using the parameters of the Gaussian function was higher(P <0.05) than that using the other functions.The mean forecast error for the Gaussian function was 14.9% in week 25(RMSE was0.21 t ha) and 5.1%-12.9% in weeks 26-30(RMSE varied from 0.06 to 0.15 t ha) according to the2013-2017 data.In weeks 31-32,the error was 5.0%-5.4%(RMSE was 0.07 t ha) using the Gaussian parameters and 7.4%-7.7%(RMSE was 0.09-0.11 t ha) for the DL function.When the method was applied to municipal districts of other soy-producing regions of the Russian Far East.RMSE was0.14-0.32 t hain weeks 25-26 and did not exceed 0.20 t hain subsequent weeks.展开更多
We used molecular genetic analyses to noninvasively identify individual Amur tigers and define subpopulations of tigers in the Russian Far East.We identified 63 individuals after genotyping 256 feces,7 hair and 11 blo...We used molecular genetic analyses to noninvasively identify individual Amur tigers and define subpopulations of tigers in the Russian Far East.We identified 63 individuals after genotyping 256 feces,7 hair and 11 blood samples collected within southern,central and northern Sikhote-Alin,as well as Southwest Primorye.Analysis of nuclear DNA at 9 microsatellite loci demonstrated greater genetic similarity between animals from southern and northern Sikhote-Alin(some 500 km apart)than between animals from Ussuriskii State Nature Reserve and Southwest Primorye(less than 10 km apart at their nearest point),suggesting that a true barrier exists preventing movements of tigers between Southwest Primorye and the southern Sikhote-Alin Mountains.展开更多
Using ab initio methods we have investigated the fluorination of graphene and find that different stoichiometric phases can be formed without a nucleation barrier, with the complete ＂2D-Teflon＂ CF phase being thermo...Using ab initio methods we have investigated the fluorination of graphene and find that different stoichiometric phases can be formed without a nucleation barrier, with the complete ＂2D-Teflon＂ CF phase being thermody- namically most stable. The fluorinated graphene is an insulator and turns out to be a perfect matrix-host for patterning nanoroads and quantum dots of pristine graphene. The electronic and magnetic properties of the nanoroads can be tuned by varying the edge orientation and width. The energy gaps between the highest occupied and lowest unoccupied molecular orbitals （HOMO-LUMO） of quantum dots are size-dependent and show a confinement typical of Dirac fermions. Furthermore, we study the effect of different basic coverage of F on graphene （with stoichiometries CF and C4F） on the band gaps, and show the suitability of these materials to host quantum dots of graphene with unique electronic properties.展开更多
The formation of runaway electron pre-ionized diffuse discharges at the pressures 0.05-0.7 MPa of in air, argon, nitrogen, and SF6 in an inhomogeneous electric field was investigated. Dynamics of intensity of the disc...The formation of runaway electron pre-ionized diffuse discharges at the pressures 0.05-0.7 MPa of in air, argon, nitrogen, and SF6 in an inhomogeneous electric field was investigated. Dynamics of intensity of the discharge plasma radiation from the different discharge gap regions in the gas pressure range （0.05-0.7 MPa） was established. It was shown that, the breakdown is occurred owing to the ionization wave, which starts from the electrode with small radius of curvature at both polarity of high voltage pulses. It is seen that formation of bright spots on the fiat electrode at the negative polarity of the electrode with small radius of curvature are observed during the changing of the discharge current polarity. It was shown that, at positive polarity of electrode with a small radius of curvature, the bright spots on the flat electrode arise due to the participation of the dynamic displacement current in the gap conductance.展开更多
By the use of non-contact atomic force microscopy （NC-AFM） and Kelvin probe force microscopy （KPFM）, we measure the local surface potential of mechanically exfoliated graphene on the prototypical insulating hydrop...By the use of non-contact atomic force microscopy （NC-AFM） and Kelvin probe force microscopy （KPFM）, we measure the local surface potential of mechanically exfoliated graphene on the prototypical insulating hydrophilic substrate of CAF2（111）. Hydration layers confined between the graphene and the CaF2 substrate, resulting from the graphene＇s preparation under ambient conditions on the hydrophilic substrate surface, are found to electronically modify the graphene as the material＇s electron density transfers from graphene to the hydration layer. Density functional theory （DFT） calculations predict that the first 2 to 3 water layers adjacent to the graphene hole-dope the graphene by several percent of a unit charge per unit cell.展开更多
Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation fac...Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation factor that generally causes growth inhibition, differentiation and/or apoptosis. In this study, we demonstrate that RA not only affects mouse RPC differentiation but also improves cell survival by reducing spontaneous apoptotic rate without affecting RPC proliferation. The enhanced cell survival was accompanied by a significant upregulation of the expression of protein kinase A （PKA） and several protein kinase C （PKC） isoforms. Treatment of cells grown in RA-free media with 8-bromoadenosine3＇,5＇-cyclic monophosphate, a known activator of PKA, resulted in an anti-apoptotic effect similar to that caused by RA; whereas the PKA inhibitor N-[2-（p-bromocinnamylamino）ethyl]-5-isoquinolinesul- fonamide dihydrochloride led to a significant （-32%） increase in apoptosis. In contrast, treatment of RPCs with any of two PKC selective inhibitors, 2,2＇,3,3＇,4,4＇-hexahydroxy-1,1 ＇-biphenyl-6,6＇-dimethanol dimethyl ether and bisindolylmaleimide XI, led to diminished apoptosis; while a PKC activator, phorbol 12-myristate 13-acetate, increased apoptosis. These and other data suggest that the effect of RA on RPC survival is mostly due to the increased anti-apoptotic activity elicited by PKA, which might in turn be antagonized by PKC. Such a mechanism is a new example of tight regulation of important biological processes triggered by RA. Although the detailed mechanisms remain to be elucidated, we provide evidence that the pro-survival effect of RA on RPCs is not mediated by changed expression of p53 or bcl-2, and appears to be independent of 15-amyloid, Fas ligand, TNF-α, ganglioside GM1 and ceramide C 16-induced apoptotic pathways.展开更多
The parameters of runaway electrons produced in nanosecond high-voltage discharges in different gases(air,nitrogen,sulphur hexafluoride,krypton,argon,methane,neon,hydrogen,helium)at atmospheric and higher pressure wer...The parameters of runaway electrons produced in nanosecond high-voltage discharges in different gases(air,nitrogen,sulphur hexafluoride,krypton,argon,methane,neon,hydrogen,helium)at atmospheric and higher pressure were studied.An optical analysis was also performed to investigate the ionisation dynamics in diffuse discharges in nitrogen and nitrogen-containing mixtures.At breakdown of a point-to-plane gap by nanosecond(≃2 ns)high-voltage(≃200 kV)pulses of negative voltage polarity and gas pressure above 0.1 MPa,a supershort avalanche electron beam(SAEB)was detected by a collector behind the flat anode.For pressure>0.1 MPa of nitrogen and other gases it is shown that the maximum pressure for SAEB registration decreases with increasing the voltage pulse rise time.Therefore,to detect a SAEB at atmospheric and higher gas pressure,one should use voltage pulses with an amplitude of hundred kilovolts and rise time of∼1 ns and shorter.The experimental research in the dynamics of optical radiation from the discharge plasma shows that the breakdown in which runaway electrons are produced develops as an ionisation wave.展开更多
Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure a...Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure air.To initiate ionization waves in a quartz tube,an electrodeless pulse-periodic discharge fed by microsecond voltage pulses with an amplitude of a few kilovolts and a repetition rate of tens of kHz were formed.In this case ionization waves(streamers)have a length of tens of centimeters.The main plasma parameters were measured at various distances along the tube.The measurements confirm the fact that ionization waves propagate in opposite directions from the zone of the main electrodeless discharge,just as it happens during the formation of red sprites.展开更多
基金supported by the National Natu-ral Science Foundation of China(Grant Nos.49872 066 and 40132020).
文摘Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tectonic settings in the period of basin deposition. Results of geochemical analyses in this paper show that sandstone samples of the Mesozoic Mohe basin fall in active continental margin settings on several kinds of tectonic discriminatory diagrams (Bhatia et al. 1983, 1986; Roser et al. 1986,1988,1999). The samples are also characterized by binary-system provenances, whose terrigenous clastic materials mainly derived from the oro- genic belt near the basin to the north and secondarily from the continental region in the south of the basin at the same time. The research results of rock geochemistry, combined with tectonic analysis, reflect that tectonic type of the basin is a foreland basin with nature of depositional ac- cumulation of molass, but not continental rift basin considered in the past. This finding provides important evidence of rock geochemistry for the original structural linkage between the Mohe Foreland Basin and Mongol-Okhotsk Orogen in Mesozoic.
文摘We aim to evaluate the incidence of incontinence following laser endoscopic enucleation of the prostate(EEP)comparing en-bloc(Group 1)versus 2-lobe/3-lobe techniques(Group 2).We performed a retrospective review of patients undergoing EEP for benign prostaticenlargement in 12 centers between January 2020 and January 2022.Data were presented as median and interquartile range(IQR).Univariable and multivariable logistic regression analysis was performed to evaluate factors associated with stress urinary incontinence(SUI)and mixed urinary incontinence(MUI).There were 1711 patients in Group 1 and 3357 patients in Group 2.Patients in Group 2were significantly younger(68[62–73]years vs 69[63–74]years,P=0.002).Median(interquartile range)prostate volume(PV)wassimilar between the groups(70[52–92]ml in Group 1 vs 70[54–90]ml in Group 2,P=0.774).There was no difference in preoperativeInternational Prostate Symptom Score,quality of life,or maximum flow rate.Enucleation,morcellation,and total surgical time weresignificantly shorter in Group 1.Within 1 month,overall incontinence rate was 6.3%in Group 1 versus 5.3%in Group 2(P=0.12),and urge incontinence was significantly higher in Group 1(55.1%vs 37.3%in Group 2,P<0.001).After 3 months,the overall rate ofincontinence was 1.7%in Group 1 versus 2.3%in Group 2(P=0.06),and SUI was significantly higher in Group 2(55.6%vs 24.1%in Group 1,P=0.002).At multivariable analysis,PV and IPSS were factors significantly associated with higher odds of transient SUI/MUI.PV,surgical time,and no early apical release technique were factors associated with higher odds of persistent SUI/MUI.
文摘In this review,we tried to systematize all the evidence(from PubMed[MEDLINE],Scopus,Cochrane Library,EBSCO,Embase,and Google Scholar)from 1993 to 2021 on the predictors of microsurgical varicocelectomy efficacy in male infertility treatment.Regarding the outcomes of varicocele repair,we considered semen improvement and pregnancy and analyzed them separately.Based on the 2011 Oxford CEBM Levels of Evidence,we assigned a score to each trial that studied the role of the predictor.We systematized the studied predictors based on the total points,which were,in turn,calculated based on the number and quality of studies that confirmed or rejected the studied predictor as significant,into three levels of significance:predictors of high,moderate,and low clinical significance.Preoperative total motile sperm count(TMSC)coupled with sperm concentration can be a significant predictor of semen improvement and pregnancy after varicocelectomy.In addition,for semen improvement alone,scrotal Doppler ultrasound(DUS)parameters,sperm DNA fragmentation index(DFI),and bilateral varicocelectomy are reliable predictors of microsurgical varicocelectomy efficacy.
基金National Key Research and Development Plan of China,Grant/Award Number:2021YFE0114700Ministry of Science and Higher Education of the Russian Federation,Grant/Award Number:075-15-2021-1026。
文摘The development of positive and negative streamers in a point-to-plane gap filled with air and nitrogen at various pressures(50-200 kPa)and voltages(8-25 kV)was studied.A four-channel intensified charge-coupled device(ICCD)and a streak-camera were used.Electrical parameters were measured with high resolution(10 GHz).An original method of measuring a displacement current caused by a streamer was applied.As was expected,positive streamer branches in nitrogen at low voltages and/or elevated pressures while a large-diameter streamer is formed in air.However,at high voltages or negative polarity,the large-diameter streamer is formed both in nitrogen and air in the entire pressure range.It was found that runaway electrons(REs)are generated in the very first picoseconds of gas ionisation near the pointed cathode.It was assumed that REs can be generated near the pointed anode and produce bremsstrahlung radiation due to a sharply inhomogeneous distribution of electrical potential.It was found that in the final stage of negative streamer development in air and nitrogen,the gas between the streamer front and the opposite electrode is ionised almost simultaneously in the entire volume when the streamer diameter is almost equal to the interelectrode gap.
文摘The prevalence of nephrolithiasis is increasing worldwide.Understanding and implementing medical therapies for kidney stone prevention are critical to prevent recurrences and decrease the economic burden of this condition.Dietary and pharmacologic therapies require understanding on the part of the patient and the prescribing practitioner in order to promote compliance.Insights into occupational exposures and antibiotic use may help uncover individual risk factors.Follow-up is essential to assess response to treatment and to modify treatment plans to maximize therapeutic benefit.
基金supported by the Russian Foundation for Basic Research (Grant No.16-03-00595)
文摘The synthesis of nanopowders of terbia compounds with scandia, yttria, and lutetia was carried out using a self-propagating high-temperature synthesis method involving a mixture of nitrates of metals and glycine as a precursor. The nanopowder phase transformations were investigated using X-ray diffraction analysis. It was found that lutetia has a negligible effect on the phase formation in terbia. On the other hand, yttrium and scandium ions significantly suppressed crystallization. The densification kinetics of nanopowders of the Tb_2O_3 compounds and the microstructure of ceramics after microwave sintering were studied using dilatometry and scanning electron microscopy. The introduction of scandia, yttria, or lutetia contributed to the intensification of the densification of the terbia ceramics when heated in a microwave field. Near full-density materials of terbia solid solutions with lutetia and yttria were obtained at about 1600–1640 ℃. The ceramics of scandia–terbia compounds contained the second phase, which causes light scattering.
文摘INTRODUCTION The saiga antelope[Saiga tatarica(Linnaeus,1766)]is an extant representative of the large herbivorous mammals’complex of Pleistocene steppe-tundra ecosystem(Bannikov et al.1961;Baryshnikov et al.1998).In the course of its evolutionary history,under the influence of global climate changes and later anthropogenic factors,the species experienced multiple changes in number and range.During the last Ice Age,the saiga range in Eurasia was integral and achieved its maximum in the entire species history:In the west,it reached the Pyrenees and the Alps,and in the east inhabited Yakutia and Chukotka(Kahlke 2014).The disintegration of the range is directly related and correlates well with the destruction of tundra ecosystems(Baryshnikov et al.1998).Currently,there are two subspecies of the saiga:the Mongolian saiga,S.t.mongolica(=S.borealis),and nominative subspecies,S.t.tatarica.The Mongolian subspecies is represented by a single saiga population in Mongolia.There are four populations of the nominative subspecies in the arid ecosystems of Kazakhstan(Ural,Betpakdala,Ustyurt populations)and Russia(Northwest Pre-Caspian population).
基金supported by the Ministry of Science and Higher Education of the Russian Federation(No.075-15-2021-1026 of November 15,2021)jointly by the National Key Research and Development Plan of China(No.2021YFE0114700)。
文摘In this paper,we discuss the properties of ionization waves(IWs)in a multi-pulsed plasma jet while using the two-dimensional computational approach.The IWs are generated by application of three short negative pulses with a repetition frequency 12.5 MHz.The simulations are performed continuously during a single run while accounting for charges accumulated inside(surface charges)and outside(space charges)the tube.The plasma forming gas mixture(He/O2=99.8%/0.2%)is injected through the discharge tube into the surrounding humid air.We show that an IW can emerge from the tube exit at a pulse rising edge(as a negative IW)and at a falling edge of the same pulse(as a positive IW).It is demonstrated that remnants of the negative and positive charges play an essential role in the discharge evolution.The first pulse travels the shortest distance as it propagates through the initially non-ionized environment.The IWs developing during the second pulse essentially enlarge the plasma plume length.At the same time,the IWs generated by the third pulse eventually decay due to the remnants of charges accumulated during the previous pulses.Accumulated memory charges can lead to the IW extinction.
基金This study was part of the long-term“Program of Studying the Amur Tiger in the Russian Far East”within the framework of the Permanent Expedition of RAS for the Study of Animals Listed of the Red Data Book of the Russian Federation and Other Highly Important Animals of the Russian Fauna as well as within the Siberian Tiger Project of the Wildlife Conservation Society(WCS-Russia).The authors are grateful to the staff of the V.L.Komarov“Ussuriskii”State Nature Reserve,FEB RAS and the Land of the Leopard National Park for fruitful support in data collection,to Dr Andrey D.Poyarkov from the A.N.Severtsov Institute of Ecology and Evolution,RAS and to Mr Alexander L.Salman for discussion and technical support.This research was made within the framework of the Program for the Study of the Amur Tiger in the Russian Far East and was supported by the Russian Geography Society。
文摘To better understand the spatial structure of Amur tigers(Panthera tigris altaica)at the southern edge of their range we fitted 14 tigers(6♀♀and 8♂♂)with 15 GPS-Argos collars between 2008 and 2011 in 2 study sites:the Ussuriskii Reserve of southern Sikhote-Alin and the Land of the Leopard National Park in southwest Primorye,Russian Far East.Fixed kernel estimates of male home ranges were larger than those of female home ranges(P<0.05[mean 95%fixed kernel♀=401±205 km2;mean 95%fixed kernel♂=778±267 km2]).The home range size of females varied greatly,but on average was similar to estimates derived from earlier work further north.Low overlap of adjacent home ranges suggested that females retained exclusive territories.Real core areas of females overlapped only slightly,and remained stable over multiple years.The home ranges of adult males were smaller than those of males to the north,and in contrast to previous studies,high overlap among males indicated the absence of territoriality.Nonetheless,real core areas of males did not overlap,suggesting some spatial separation.In comparison to other tiger populations and other areas of the Russian Far East,the sex ratio in our 2 study areas was highly skewed towards males.We believe this skewed sex ratio resulted in the dissolution of territoriality of males due to an inability to defend individual females,with males resorting to scramble competition for mates.Continued monitoring of these sites to determine whether shifts in the sex ratio might result in a return to male territoriality would provide confirmation of our tentative hypothesis.
文摘Forecasting crop yields based on remote sensing data is one of the most important tasks in agriculture.Soybean is the main crop in the Russian Far East.It is desirable to forecast soybean yield as early as possible while maintaining high accuracy.This study aimed to investigate seasonal time series of the normalized difference vegetation index(NDVI) to achieve early forecasting of soybean yield.This research used data from the Moderate Resolution Image Spectroradiometer(MODIS),an arable-land mask obtained from the VEGA-Science web service,and soybean yield data for 2008-2017 for the Jewish Autonomous Region(JAR) districts.Four approximating functions were fitted to model the NDVI time series:Gaussian,double logistic(DL),and quadratic and cubic polynomials.In the period from calendar weeks 22-42(end of May to mid-October),averaged over two districts,the model using the DL function showed the highest accuracy(mean absolute percentage error-4.0%,root mean square error(RMSE)-0.029,P <0.01).The yield forecast accuracy of prediction in the period of weeks 25-30 in JAR municipalities using the parameters of the Gaussian function was higher(P <0.05) than that using the other functions.The mean forecast error for the Gaussian function was 14.9% in week 25(RMSE was0.21 t ha) and 5.1%-12.9% in weeks 26-30(RMSE varied from 0.06 to 0.15 t ha) according to the2013-2017 data.In weeks 31-32,the error was 5.0%-5.4%(RMSE was 0.07 t ha) using the Gaussian parameters and 7.4%-7.7%(RMSE was 0.09-0.11 t ha) for the DL function.When the method was applied to municipal districts of other soy-producing regions of the Russian Far East.RMSE was0.14-0.32 t hain weeks 25-26 and did not exceed 0.20 t hain subsequent weeks.
文摘We used molecular genetic analyses to noninvasively identify individual Amur tigers and define subpopulations of tigers in the Russian Far East.We identified 63 individuals after genotyping 256 feces,7 hair and 11 blood samples collected within southern,central and northern Sikhote-Alin,as well as Southwest Primorye.Analysis of nuclear DNA at 9 microsatellite loci demonstrated greater genetic similarity between animals from southern and northern Sikhote-Alin(some 500 km apart)than between animals from Ussuriskii State Nature Reserve and Southwest Primorye(less than 10 km apart at their nearest point),suggesting that a true barrier exists preventing movements of tigers between Southwest Primorye and the southern Sikhote-Alin Mountains.
文摘Using ab initio methods we have investigated the fluorination of graphene and find that different stoichiometric phases can be formed without a nucleation barrier, with the complete ＂2D-Teflon＂ CF phase being thermody- namically most stable. The fluorinated graphene is an insulator and turns out to be a perfect matrix-host for patterning nanoroads and quantum dots of pristine graphene. The electronic and magnetic properties of the nanoroads can be tuned by varying the edge orientation and width. The energy gaps between the highest occupied and lowest unoccupied molecular orbitals （HOMO-LUMO） of quantum dots are size-dependent and show a confinement typical of Dirac fermions. Furthermore, we study the effect of different basic coverage of F on graphene （with stoichiometries CF and C4F） on the band gaps, and show the suitability of these materials to host quantum dots of graphene with unique electronic properties.
基金Acknowledgments The work was supported by the grant from the Russian Science Foundation, project No. 14-29-00052.
文摘The formation of runaway electron pre-ionized diffuse discharges at the pressures 0.05-0.7 MPa of in air, argon, nitrogen, and SF6 in an inhomogeneous electric field was investigated. Dynamics of intensity of the discharge plasma radiation from the different discharge gap regions in the gas pressure range （0.05-0.7 MPa） was established. It was shown that, the breakdown is occurred owing to the ionization wave, which starts from the electrode with small radius of curvature at both polarity of high voltage pulses. It is seen that formation of bright spots on the fiat electrode at the negative polarity of the electrode with small radius of curvature are observed during the changing of the discharge current polarity. It was shown that, at positive polarity of electrode with a small radius of curvature, the bright spots on the flat electrode arise due to the participation of the dynamic displacement current in the gap conductance.
文摘By the use of non-contact atomic force microscopy （NC-AFM） and Kelvin probe force microscopy （KPFM）, we measure the local surface potential of mechanically exfoliated graphene on the prototypical insulating hydrophilic substrate of CAF2（111）. Hydration layers confined between the graphene and the CaF2 substrate, resulting from the graphene＇s preparation under ambient conditions on the hydrophilic substrate surface, are found to electronically modify the graphene as the material＇s electron density transfers from graphene to the hydration layer. Density functional theory （DFT） calculations predict that the first 2 to 3 water layers adjacent to the graphene hole-dope the graphene by several percent of a unit charge per unit cell.
文摘Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation factor that generally causes growth inhibition, differentiation and/or apoptosis. In this study, we demonstrate that RA not only affects mouse RPC differentiation but also improves cell survival by reducing spontaneous apoptotic rate without affecting RPC proliferation. The enhanced cell survival was accompanied by a significant upregulation of the expression of protein kinase A （PKA） and several protein kinase C （PKC） isoforms. Treatment of cells grown in RA-free media with 8-bromoadenosine3＇,5＇-cyclic monophosphate, a known activator of PKA, resulted in an anti-apoptotic effect similar to that caused by RA; whereas the PKA inhibitor N-[2-（p-bromocinnamylamino）ethyl]-5-isoquinolinesul- fonamide dihydrochloride led to a significant （-32%） increase in apoptosis. In contrast, treatment of RPCs with any of two PKC selective inhibitors, 2,2＇,3,3＇,4,4＇-hexahydroxy-1,1 ＇-biphenyl-6,6＇-dimethanol dimethyl ether and bisindolylmaleimide XI, led to diminished apoptosis; while a PKC activator, phorbol 12-myristate 13-acetate, increased apoptosis. These and other data suggest that the effect of RA on RPC survival is mostly due to the increased anti-apoptotic activity elicited by PKA, which might in turn be antagonized by PKC. Such a mechanism is a new example of tight regulation of important biological processes triggered by RA. Although the detailed mechanisms remain to be elucidated, we provide evidence that the pro-survival effect of RA on RPCs is not mediated by changed expression of p53 or bcl-2, and appears to be independent of 15-amyloid, Fas ligand, TNF-α, ganglioside GM1 and ceramide C 16-induced apoptotic pathways.
基金supported by the Russian Science Foundation(the project#14-29-00052).
文摘The parameters of runaway electrons produced in nanosecond high-voltage discharges in different gases(air,nitrogen,sulphur hexafluoride,krypton,argon,methane,neon,hydrogen,helium)at atmospheric and higher pressure were studied.An optical analysis was also performed to investigate the ionisation dynamics in diffuse discharges in nitrogen and nitrogen-containing mixtures.At breakdown of a point-to-plane gap by nanosecond(≃2 ns)high-voltage(≃200 kV)pulses of negative voltage polarity and gas pressure above 0.1 MPa,a supershort avalanche electron beam(SAEB)was detected by a collector behind the flat anode.For pressure>0.1 MPa of nitrogen and other gases it is shown that the maximum pressure for SAEB registration decreases with increasing the voltage pulse rise time.Therefore,to detect a SAEB at atmospheric and higher gas pressure,one should use voltage pulses with an amplitude of hundred kilovolts and rise time of∼1 ns and shorter.The experimental research in the dynamics of optical radiation from the discharge plasma shows that the breakdown in which runaway electrons are produced develops as an ionisation wave.
基金funded by the Ministry of Science and Higher Education of the Russian Federation within Agreement no.075-15-2021-1026 of November 15,2021.
文摘Over the past three decades,research of high-altitude atmospheric discharges has received a lot of attention.This paper presents the results of experimental modeling of red sprites during a discharge in low-pressure air.To initiate ionization waves in a quartz tube,an electrodeless pulse-periodic discharge fed by microsecond voltage pulses with an amplitude of a few kilovolts and a repetition rate of tens of kHz were formed.In this case ionization waves(streamers)have a length of tens of centimeters.The main plasma parameters were measured at various distances along the tube.The measurements confirm the fact that ionization waves propagate in opposite directions from the zone of the main electrodeless discharge,just as it happens during the formation of red sprites.
