The aim of this research is to investigate the patterns of vascular plant species richness,diversity,and distribution along an elevation gradient in the Abune Yosef mountain range,Ethiopia.Preferential systematic samp...The aim of this research is to investigate the patterns of vascular plant species richness,diversity,and distribution along an elevation gradient in the Abune Yosef mountain range,Ethiopia.Preferential systematic sampling was employed to collect vegetation and environmental data along the elevation gradient.We found that plant species richness declines monotonically from low to high elevations.Specifically,vascular plant species richness and diversity were lower in the Afroalpine grassland(high elevation)than in the Dry evergreen Afromontane forest and Ericaceous forest(low elevations).In contrast,endemic vascular plant richness was significantly higher in the Afroalpine grassland than in the Dry evergreen Afromontane forest and Ericaceous forest.Elevation showed a significant impact on the richness,diversity,and endemism of vascular plants.According to Sorensen's coefficient,the similarity between Dry evergreen Afromontane forest and Ericaceous forest vegetation types is higher(32%)than the similarity between Ericaceous forest and Afroalpine grassland(18%).Only 5%similarity was recorded between the Dry evergreen Afromontane forest and Afroalpine grassland.Growth forms showed different elevationai richness patterns.Trees and liana increased monotonically up to 3300 m.Shrub and herb richness patterns followed a hump-shaped and inverted hump-shaped pattern along the elevation gradient.The elevation patterns of vascular plant species richness,diversity,and growth form in the present study may be attributed to differences in management intensity,spatial heterogeneity,microclimatic variations,and anthropogenic disturbances.展开更多
The aim of this study is to detect whether the quantitative textural features of optical coherencetomography angiography (OCTA) images can be used to detect the eyes in the early stage ofdiabetic retinopathy (DR) from...The aim of this study is to detect whether the quantitative textural features of optical coherencetomography angiography (OCTA) images can be used to detect the eyes in the early stage ofdiabetic retinopathy (DR) from eyes with diabetes and no DR (NDR). Textural features includingfractal dimension, contrast, correlation, entropy, energy, and homogeneity were calculatedfrom the OCTA images. The Student's t-test was performed to identify the textural featuresthat can be able to detect DR in the early stage. The area under the receiver operating characteristic(AUROC) curves, sensitivity, and specicity were calculated between the study groups.Our results indicated that the fractal dimension in ICP and SVP and the correlation in SVCshowed the statistical signicance between mild NPDR patients and NDR patients. The ROCanalysis results showed that the AUROC of the fractal dimension in ICP was 0.736 with 0.773sensitivity and 0.700 specicity. The cuto® point in ICP was 2.616. The OCTA-based fractaldimension was able to discriminate diabetic eyes with early retinopathy from healthy and NDRwith higher sensitivity and specicity. The OCTA-based correlation showed the power to differentiatethe mild NPDR eyes from the normal healthy and diabetic eyes. These results suggestthat texture-based features of OCTA have the potential to assist in the assessment of therapeuticinterventions to prevent early DR in diabetic subjects.展开更多
Complex investigation of mesh implants was per formed involving laser confocal microscopy,backscattered probing and OCT imaging methods.The growth of endomysium and fat tissue with microcirculation vessels was observe...Complex investigation of mesh implants was per formed involving laser confocal microscopy,backscattered probing and OCT imaging methods.The growth of endomysium and fat tissue with microcirculation vessels was observed in the mesh encapsulation region.Confocal microscopy analysis shows that such pat hologies complications such as necrosis formation and microcavities were localized in the area near implant fibers with the size compatible with fiber diameter.And the number of such formnations increase with the increase of the size,number and density of microdefects on the implant surface.Results of mumerical sinulations show that it is possible to control implant installation up to the depth to 4mm with a help of bac kscattering probing.The applicability of OCT imaging for mesh implant control was demonstrated.Special two stage OCT image noise reduction algorithm,including empirical mode decomposition,was proposed for contrast increase and better abnormalities visualization by halving the signal-to-noise ratio.Joint usage of backscattered probing and OCT allows to accurately ascertain implant and surrounding tissue conditions,which reduces the risk of relapse probability.展开更多
We describe parallel implementation of the metaheuristic approach to the problem of comparing strings representing DNA sequence. By this approach, one can define a whole new class of metrics on a set of strings;some o...We describe parallel implementation of the metaheuristic approach to the problem of comparing strings representing DNA sequence. By this approach, one can define a whole new class of metrics on a set of strings;some of this metrics can lead to interesting results when used for string comparison. We propose several heuristics;compare results achieved when using those heuristics and compare parallel and sequential implementation of proposed approach.展开更多
The light propagation through system a polarizer-analyzer is investigated on the basis of quantum conceptions about the nature of light. It is shown, that Malus law based on principles of classical electrodynamics not...The light propagation through system a polarizer-analyzer is investigated on the basis of quantum conceptions about the nature of light. It is shown, that Malus law based on principles of classical electrodynamics not completely takes into account all effects which can occur at the light propagation through system a polarizer-analyzer. The phenomenon of possible change of frequency of light in particular drops out, for example in the region of X-ray radiation. The deduction of Malus law based on quantum principles is given. For comparison the differential effective section of interaction of a photon and electron with take into account of rotation of a plane of polarization of a photon in Compton’s effect is found.展开更多
The Boltzmann kinetic equation for rarefied radiating gas is found. It is shown, that process of radiation is defined by excitation of atoms at their collision, and also spontaneous radiation of quantums at transition...The Boltzmann kinetic equation for rarefied radiating gas is found. It is shown, that process of radiation is defined by excitation of atoms at their collision, and also spontaneous radiation of quantums at transition of electrons to the basic power level and the compelled radiation of quantums at collision of the excited atoms. It is shown, that distributions on velocities of the excited and not excited atoms submit to various laws. Distinctions in laws of distribution of the excited and not excited atoms define power parameters of radiating gas, and also a share of radiating molecules in gas.展开更多
The reasons of angular photon distribution occurrence at electron-positron annihilation are considered. It is shown that angular photon distribution is consequence of Doppler’s effect in the reference frame of the el...The reasons of angular photon distribution occurrence at electron-positron annihilation are considered. It is shown that angular photon distribution is consequence of Doppler’s effect in the reference frame of the electron and positron mass center. In the reference frame bound with moving electron the angular photon distribution is absent. But it is replaced by the Doppler’s shift of photons frequencies. The received results are applied to the analysis of a positron-emission tomograph work.展开更多
Two elementary particles—a photon and a graviton—responsible for interaction with physical objects of two long-range action fields electromagnetic and gravitational are considered. The similarity and distinction of ...Two elementary particles—a photon and a graviton—responsible for interaction with physical objects of two long-range action fields electromagnetic and gravitational are considered. The similarity and distinction of these quantum particles are investigated. It is shown that these particles essentially differ from each other. First of all, they are in different spaces. The photon is in photon space, and the graviton is in Riemann’s space-time. Interaction of a photon and a mass body cannot be calculated in Euclidian space. Interaction of a graviton and a mass body can be calculated in the Euclidian space. Polarizing properties of a gravitational wave both in plane Minkowski’s space, and in curved Riemann’s space-time are in detail considered. The differential equation of a gravitational quantum oscillator is found and its solution is analyzed. Also, the quantum metrics of Riemann’s space-time in presence of graviton and its quantum numbers are found.展开更多
The paper presents an improved technique of calculating total deflections of flexural reinforced concrete elements that takes discrete crack formation into account. The technique is based on determining the curvature ...The paper presents an improved technique of calculating total deflections of flexural reinforced concrete elements that takes discrete crack formation into account. The technique is based on determining the curvature of the cross section of reinforced concrete elements with cracks and fissures in the area between cracks. The curvature of the element is calculated using a non-linear function of the deformation of concrete under compression. Approximating dependency of concrete resistance on compression developed by one of the authors is presented. An algorithm of finding the curvature and formulas for calculating curvature and deflection are provided. The function of the curvature distribution along the length of a flexible element is proposed by the authors. The paper also presents the results of the author＇s experimental research. The characteristics of samples tested are described. The experimental research results of deflections of fiexural reinforced concrete elements made of conventional and high-strength concretes are presented. Comparison of the values calculated using the technique with those obtained from the experimental research as well as those calculated according to existing regulations in Russia, USA and Europe is drawn.展开更多
Scanning electrochemical microscopy (SECM) feedback mode has been used to investigate regeneration kinetics on P1 (4-(bis-{4-[5-(2,2-dicyanovinyl) thiophene-2-yl] pH-enyl} amino) benzoic acid) dye sensitized nickel ox...Scanning electrochemical microscopy (SECM) feedback mode has been used to investigate regeneration kinetics on P1 (4-(bis-{4-[5-(2,2-dicyanovinyl) thiophene-2-yl] pH-enyl} amino) benzoic acid) dye sensitized nickel oxide (NiO) electrodes in contact with reduced iodide liquid electrolyte in different electrolyte solvents. We were used acetonitrile, ethanol, methanol and propylene carbonate solvents for comparison under illumination of different wavelengths. We found significant variation of regeneration kinetics parameters such as regeneration rate constant (<em>k<sub>eff</sub></em>), the reduction rate constant (<em>k<sub>red</sub></em>) and absorption cross-section (Φhv) in different illumination intensity and different solvents.展开更多
Scanning electrochemical microscopy (SECM) feedback mode has been used to investigate kinetics of dye regeneration in DSSC. Organic dye C343 and CW1 are used as sensitizers for nickel oxide (NiO) photoelectrochemical ...Scanning electrochemical microscopy (SECM) feedback mode has been used to investigate kinetics of dye regeneration in DSSC. Organic dye C343 and CW1 are used as sensitizers for nickel oxide (NiO) photoelectrochemical cells. The influence of film thickness on dye regeneration kinetics in the films for NiO/C343 for six different films was investigated. SECM was used to analyze effective rate constant, <em>k</em><sub>eff</sub> and reduction rate <em>k</em><sub>red</sub>, absorption cross section, <em>Φ</em><sub>hv</sub> for the dye regeneration process. The data reveal a significant variation of <em>k</em><sub>eff</sub> and <em>k</em><sub>red</sub> with a variation of light intensity, sample thickness and dye difference. This research found remarkable dependence of the dye regeneration kinetic parameters on illumination flux, dye types and film thickness of electrode.展开更多
In this paper,we present the electric field controllable diffractive optical elements in strontium-barium niobate single crystals with stable tailored spiral-shaped domain structure and demonstrate the generation of o...In this paper,we present the electric field controllable diffractive optical elements in strontium-barium niobate single crystals with stable tailored spiral-shaped domain structure and demonstrate the generation of optical beam with orbital angular momentum.The required domain pattern was created in the sample with initial domain structure by electric field application using the photolithographically defined liquid electrode.A series of bipolar triangular electric field pulses were applied to the sample for determination of the optimal parameters for complete polarization switching under the electrode.The stable tailored domain pattern of the spiral shape was created by the application of the unipolar pulse of a special shape.The complete switching under the electrode and partial switching under the photoresist layer have been revealed.The imaging by Cherenkov-type second harmonic generation microscopy confirmed that the created domain structure reaches the opposite polar surface.The imaging of the diffraction pattern of the laser beam passing through a voltage-biased DOE confirmed the formation of the beam with orbital angular momentum.The half-wave voltages of 237V and 302 V for wavelength 632.8 nm and 532 nm,respectively,for 2-mmthick sample were measured.The obtained knowledge can be used for the development of domain engineering methods in strontium-barium niobate single crystals for the creation of tailored domain structures for manufacturing of electric field controllablediffractiveoptical elements.展开更多
Surface-enhanced Raman spectroscopy(SERS)is a promising analytical method for studying the structure and composition of multi-component media in clinical practice.However,the practical application of SERS imposes seve...Surface-enhanced Raman spectroscopy(SERS)is a promising analytical method for studying the structure and composition of multi-component media in clinical practice.However,the practical application of SERS imposes several conditions and restrictions depending on the required analytical accuracy and implementation complexity.This paper proposes a simple serum SERS technique for diagnosing multiple myeloma(MM).The process utilises a substrate composed of agglomerated spherical silver particles(~200 nm)with a capillary effect on sodium nitrate crystals(0.02%volume concentration),excited at a wavelength of 785 nm.Spectral characteristics were recorded using a detector without external cooling,ensuring a cost-effective approach.The proposed low-cost approach was tested on 31 samples from MM and 102 serum samples from an age-matched control group.Combining the SERS technique with the multivariate analysis for serum testing provided high discrimination rates for MM patients compared to the control patients,with an average accuracy of over 96%.Biochemical interpretation of the recorded spectra identified the informative bands at 635 cm^(-1),723 cm^(-1),and 1052 cm^(-1).Overall,the proposed SERSbased tool can become the basis for screening for MM and can be easily integrated into clinical practice,expanding diagnostic capabilities where expensive laboratory techniques are not affordable.展开更多
This article presents a device for the storage and gasification of cryogenic working fluid,which is named a cryogenic fuelling tank.A cryogenic fuel tank can serve both as a fuel vessel and a pressure accumulator due ...This article presents a device for the storage and gasification of cryogenic working fluid,which is named a cryogenic fuelling tank.A cryogenic fuel tank can serve both as a fuel vessel and a pressure accumulator due to the regasification process that takes place inside.Application of this tank is slowed by the lack of theoretical and experimental research on its working process.This article deals with an investigation of the working process of the energy plant based on a cryogenic fuel tank coupled with a rotor-vane expander.Developed mathematical models include evaporation and condensation processes within the tank,heat exchange between gas chambers and between the tank and environment,and changes in energy due to incoming and leaving mass.Mechanical work used to determine the efficiency of a power plant is generated by a steam expander.Research shows that it is possible to achieve specific work outputs up to 110-160 kJ/kg with relative deviation of power and specific work determination equal to 1.4% and 1.9%correspondingly.展开更多
Background:Onchocerciasis(river blindness),caused by the filarial worm speciesOnchocerca volvulus,is a serious vector-borne neglected tropical disease(NTD)of public health and socioeconomic concern.It is transmitted t...Background:Onchocerciasis(river blindness),caused by the filarial worm speciesOnchocerca volvulus,is a serious vector-borne neglected tropical disease(NTD)of public health and socioeconomic concern.It is transmitted through the bite of black flies of the genusSimulium,and manifested in dermal and ocular lesions.Ninety-nine percent of the total global risk and burden of onchocerciasis is in Africa.This scoping review examines the key challenges related to the elimination of onchocerciasis by 2020-2025 in Africa,and proposes recommendations to overcome the challenges and accelerate disease elimination.To find relevant articles published in peer-reviewed journals,a search of PubMed and Google Scholar databases was carried out.Main text:Rigorous regional interventions carried out to control and eliminate onchocerciasis in the past four decades in Africa have been effective in bringing the disease burden under control;it is currently not a public health problem in most endemic areas.Notably,transmission of the parasite is interrupted in some hyperendemic localities.Recently,there has been a policy shift from control to complete disease elimination by 2020 in selected countries and by 2025 in the majority of endemic African countries.The WHO has published guidelines for stopping mass drug administration(MDA)and verifying the interruption of transmission and elimination of human onchocerciasis.Therefore,countries have revised their plans,established a goal of disease elimination in line with an evidence based decision to stop MDA and verify elimination,and incorporated it into their NTDs national master plans.Nevertheless,challenges remain pertaining to the elimination of onchocerciasis in Africa.The challenge we review in this paper are:incomplete elimination mapping of all transmission zones,co-endemicity of onchocerciasis and loiasis,possible emergence of ivermectin resistance,uncoordinated cross-border elimination efforts,conflict and civil unrest,suboptimal program implementation,and technical and financial challenges.This paper also proposes recommendations to overcome the challenges and accelerate disease elimination.These are:a need for complete disease elimination mapping,a need for collaborative elimination activities between national programs,a need for a different drug distribution approach in conflict-affected areas,a need for routine monitoring and evaluation of MDA programs,a need for implementing alternative treatment strategies(ATSs)in areas with elimination anticipated beyond 2025,and a need for strong partnerships and continued funding.Conclusions:National programs need to regularly monitor and evaluate the performance and progress of their interventions,while envisaging the complete elimination of onchocerciasis from their territory.Factors hindering the targeted goal of interruption of parasite transmission need to be identified and remedial actions should be taken.If possible and appropriate,ATSs need to be implemented to accelerate disease elimination by 2025.展开更多
Introduction:Soil is the major reservoir of organic carbon.There is a paucity of soil organic carbon(SOC)stock data of afroalpine and sub-afroalpine vegetation in Ethiopia.Hence,this study was conducted to estimate th...Introduction:Soil is the major reservoir of organic carbon.There is a paucity of soil organic carbon(SOC)stock data of afroalpine and sub-afroalpine vegetation in Ethiopia.Hence,this study was conducted to estimate the SOC stock and correlate it with soil physicochemical properties in Abune Yosef afroalpine and sub-afroalpine vegetation.Systematic sampling was employed to collect soil samples from upper 30 cm.Dry bulk density soil pH(1:2.5 water);organic carbon(Walkley and Black),and total nitrogen(Kjeldahl)were the methods used for soil analysis.Pearson correlation and linear regression analysis were performed in SPSS 24 statistical software.Results:The SOC stock of the study area was found to be 79.57 t C ha−1.Soil organic carbon stock showed statistically significant positive correlation with vegetation type(r=0.522,p<0.01),bulk density(r=0.62,p<0.01),total nitrogen(r=0.41,p<0.01),and altitude(r=0.468,p<0.01)and negative correlation with slope(r=−0.298,p<0.05).The present study revealed similar soil organic carbon stock(SOCS)with the Intergovernmental Panel on Climate Change(IPCC)default estimate for similar regions.Positive correlation of SOCS and altitude could be resulted from the variations in anthropogenic disturbances,temperature,and precipitation vegetation types.The negative correlation between SOCS and slope is the result from the predictably higher soil erosion at steeper slopes.Temporal livestock trampling increased the bulk density but never affected the SOCS to decline.Aspect did not show any significant relationship with SOCS due to either the under surveying of all aspects or similar solar radiation found in the study area.Moreover,gazing,aspect,and soil pH did not show statistically significant impact on SOCS.Conclusion:The SOCS of Abune Yosef afroalpine and sub-afroalpine vegetation is similar to the IPCC default estimate for similar regions.This is a great contribution both to the global and local terrestrial carbon sink.展开更多
Although tin monoxide (SnO) is an interesting compound due to its p-type conductivity,a widespread application of SnO has been limited by its narrow band gap of 0.7 eV.In this work,we theoretically investigate the str...Although tin monoxide (SnO) is an interesting compound due to its p-type conductivity,a widespread application of SnO has been limited by its narrow band gap of 0.7 eV.In this work,we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals.Our calculations reveal that a metastable SnO (β-SnO),which possesses space group P2_(1)/c and a wide band gap of 1.9 eV,is more stable than α-SnO at pressures higher than 80 GPa.Moreover,a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa.Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa.Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO →α-SnO.Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure.Finally,our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0-9 GPa)through a semiconductor-to-metal transition,while maintaining transparency in the visible light range.展开更多
The search for new materials requires effective methods for scanning the space of atomic configurations,in which the number is infinite.Here we present an extensive application of a topological network model of solid-...The search for new materials requires effective methods for scanning the space of atomic configurations,in which the number is infinite.Here we present an extensive application of a topological network model of solid-state transformations,which enables one to reduce this infinite number to a countable number of the regions corresponding to topologically different crystalline phases.We have used this model to successfully generate carbon allotropes starting from a very restricted set of initial structures;the generation procedure has required only three steps to scan the configuration space around the parents.As a result,we have obtained all known carbon structures within the specified set of restrictions and discovered 224 allotropes with lattice energy ranging in 0.16–1.76 eV atom^(−1) above diamond including a phase,which is denser and probably harder than diamond.We have shown that this phase has a quite different topological structure compared to the hard allotropes from the diamond polytypic series.We have applied the tiling approach to explore the topology of the generated phases in more detail and found that many phases possessing high hardness are built from the tiles confined by six-membered rings.We have computed the mechanical properties for the generated allotropes and found simple dependences between their density,bulk,and shear moduli.展开更多
基金Addis Ababa University office of vice president for research and Technology transfer for funding the thematic research, “Integrated approaches of Molecular Systematics and plant Biodiversity Informatics to Climate Change Mitigation and Monitoring in Ethiopian Mountains”
文摘The aim of this research is to investigate the patterns of vascular plant species richness,diversity,and distribution along an elevation gradient in the Abune Yosef mountain range,Ethiopia.Preferential systematic sampling was employed to collect vegetation and environmental data along the elevation gradient.We found that plant species richness declines monotonically from low to high elevations.Specifically,vascular plant species richness and diversity were lower in the Afroalpine grassland(high elevation)than in the Dry evergreen Afromontane forest and Ericaceous forest(low elevations).In contrast,endemic vascular plant richness was significantly higher in the Afroalpine grassland than in the Dry evergreen Afromontane forest and Ericaceous forest.Elevation showed a significant impact on the richness,diversity,and endemism of vascular plants.According to Sorensen's coefficient,the similarity between Dry evergreen Afromontane forest and Ericaceous forest vegetation types is higher(32%)than the similarity between Ericaceous forest and Afroalpine grassland(18%).Only 5%similarity was recorded between the Dry evergreen Afromontane forest and Afroalpine grassland.Growth forms showed different elevationai richness patterns.Trees and liana increased monotonically up to 3300 m.Shrub and herb richness patterns followed a hump-shaped and inverted hump-shaped pattern along the elevation gradient.The elevation patterns of vascular plant species richness,diversity,and growth form in the present study may be attributed to differences in management intensity,spatial heterogeneity,microclimatic variations,and anthropogenic disturbances.
基金the Zhejiang Provincial Natural Science Foundation(LY20H180009)the Qianjiang Talent Plan(QJD1803009)+2 种基金the Ningbo Science and Technology Service Industry Demonstration Project(2020F031)the Ningbo Natural Science Foundation(2018A610362)the Ministry of Science and Higher Education of the Russian Federation as part of the program for increasing the competitiveness of Samara University among the world's leading research and educational centers for 2013–2020.
文摘The aim of this study is to detect whether the quantitative textural features of optical coherencetomography angiography (OCTA) images can be used to detect the eyes in the early stage ofdiabetic retinopathy (DR) from eyes with diabetes and no DR (NDR). Textural features includingfractal dimension, contrast, correlation, entropy, energy, and homogeneity were calculatedfrom the OCTA images. The Student's t-test was performed to identify the textural featuresthat can be able to detect DR in the early stage. The area under the receiver operating characteristic(AUROC) curves, sensitivity, and specicity were calculated between the study groups.Our results indicated that the fractal dimension in ICP and SVP and the correlation in SVCshowed the statistical signicance between mild NPDR patients and NDR patients. The ROCanalysis results showed that the AUROC of the fractal dimension in ICP was 0.736 with 0.773sensitivity and 0.700 specicity. The cuto® point in ICP was 2.616. The OCTA-based fractaldimension was able to discriminate diabetic eyes with early retinopathy from healthy and NDRwith higher sensitivity and specicity. The OCTA-based correlation showed the power to differentiatethe mild NPDR eyes from the normal healthy and diabetic eyes. These results suggestthat texture-based features of OCTA have the potential to assist in the assessment of therapeuticinterventions to prevent early DR in diabetic subjects.
基金supported by the Federal Target Program“Scientific and scientific-pedagogic staff of innovative Russia in 2007-2013”.
文摘Complex investigation of mesh implants was per formed involving laser confocal microscopy,backscattered probing and OCT imaging methods.The growth of endomysium and fat tissue with microcirculation vessels was observed in the mesh encapsulation region.Confocal microscopy analysis shows that such pat hologies complications such as necrosis formation and microcavities were localized in the area near implant fibers with the size compatible with fiber diameter.And the number of such formnations increase with the increase of the size,number and density of microdefects on the implant surface.Results of mumerical sinulations show that it is possible to control implant installation up to the depth to 4mm with a help of bac kscattering probing.The applicability of OCT imaging for mesh implant control was demonstrated.Special two stage OCT image noise reduction algorithm,including empirical mode decomposition,was proposed for contrast increase and better abnormalities visualization by halving the signal-to-noise ratio.Joint usage of backscattered probing and OCT allows to accurately ascertain implant and surrounding tissue conditions,which reduces the risk of relapse probability.
文摘We describe parallel implementation of the metaheuristic approach to the problem of comparing strings representing DNA sequence. By this approach, one can define a whole new class of metrics on a set of strings;some of this metrics can lead to interesting results when used for string comparison. We propose several heuristics;compare results achieved when using those heuristics and compare parallel and sequential implementation of proposed approach.
文摘The light propagation through system a polarizer-analyzer is investigated on the basis of quantum conceptions about the nature of light. It is shown, that Malus law based on principles of classical electrodynamics not completely takes into account all effects which can occur at the light propagation through system a polarizer-analyzer. The phenomenon of possible change of frequency of light in particular drops out, for example in the region of X-ray radiation. The deduction of Malus law based on quantum principles is given. For comparison the differential effective section of interaction of a photon and electron with take into account of rotation of a plane of polarization of a photon in Compton’s effect is found.
文摘The Boltzmann kinetic equation for rarefied radiating gas is found. It is shown, that process of radiation is defined by excitation of atoms at their collision, and also spontaneous radiation of quantums at transition of electrons to the basic power level and the compelled radiation of quantums at collision of the excited atoms. It is shown, that distributions on velocities of the excited and not excited atoms submit to various laws. Distinctions in laws of distribution of the excited and not excited atoms define power parameters of radiating gas, and also a share of radiating molecules in gas.
文摘The reasons of angular photon distribution occurrence at electron-positron annihilation are considered. It is shown that angular photon distribution is consequence of Doppler’s effect in the reference frame of the electron and positron mass center. In the reference frame bound with moving electron the angular photon distribution is absent. But it is replaced by the Doppler’s shift of photons frequencies. The received results are applied to the analysis of a positron-emission tomograph work.
文摘Two elementary particles—a photon and a graviton—responsible for interaction with physical objects of two long-range action fields electromagnetic and gravitational are considered. The similarity and distinction of these quantum particles are investigated. It is shown that these particles essentially differ from each other. First of all, they are in different spaces. The photon is in photon space, and the graviton is in Riemann’s space-time. Interaction of a photon and a mass body cannot be calculated in Euclidian space. Interaction of a graviton and a mass body can be calculated in the Euclidian space. Polarizing properties of a gravitational wave both in plane Minkowski’s space, and in curved Riemann’s space-time are in detail considered. The differential equation of a gravitational quantum oscillator is found and its solution is analyzed. Also, the quantum metrics of Riemann’s space-time in presence of graviton and its quantum numbers are found.
文摘The paper presents an improved technique of calculating total deflections of flexural reinforced concrete elements that takes discrete crack formation into account. The technique is based on determining the curvature of the cross section of reinforced concrete elements with cracks and fissures in the area between cracks. The curvature of the element is calculated using a non-linear function of the deformation of concrete under compression. Approximating dependency of concrete resistance on compression developed by one of the authors is presented. An algorithm of finding the curvature and formulas for calculating curvature and deflection are provided. The function of the curvature distribution along the length of a flexible element is proposed by the authors. The paper also presents the results of the author＇s experimental research. The characteristics of samples tested are described. The experimental research results of deflections of fiexural reinforced concrete elements made of conventional and high-strength concretes are presented. Comparison of the values calculated using the technique with those obtained from the experimental research as well as those calculated according to existing regulations in Russia, USA and Europe is drawn.
文摘Scanning electrochemical microscopy (SECM) feedback mode has been used to investigate regeneration kinetics on P1 (4-(bis-{4-[5-(2,2-dicyanovinyl) thiophene-2-yl] pH-enyl} amino) benzoic acid) dye sensitized nickel oxide (NiO) electrodes in contact with reduced iodide liquid electrolyte in different electrolyte solvents. We were used acetonitrile, ethanol, methanol and propylene carbonate solvents for comparison under illumination of different wavelengths. We found significant variation of regeneration kinetics parameters such as regeneration rate constant (<em>k<sub>eff</sub></em>), the reduction rate constant (<em>k<sub>red</sub></em>) and absorption cross-section (Φhv) in different illumination intensity and different solvents.
文摘Scanning electrochemical microscopy (SECM) feedback mode has been used to investigate kinetics of dye regeneration in DSSC. Organic dye C343 and CW1 are used as sensitizers for nickel oxide (NiO) photoelectrochemical cells. The influence of film thickness on dye regeneration kinetics in the films for NiO/C343 for six different films was investigated. SECM was used to analyze effective rate constant, <em>k</em><sub>eff</sub> and reduction rate <em>k</em><sub>red</sub>, absorption cross section, <em>Φ</em><sub>hv</sub> for the dye regeneration process. The data reveal a significant variation of <em>k</em><sub>eff</sub> and <em>k</em><sub>red</sub> with a variation of light intensity, sample thickness and dye difference. This research found remarkable dependence of the dye regeneration kinetic parameters on illumination flux, dye types and film thickness of electrode.
基金support of the Ministry of Science and Higher Education of the Russian Federation(state task FEUZ-2023-0017)The equipment of the Ural Center for Shared Use“"Modern nanotechnology"Ural Federal University(Reg.No 2968)was used.
文摘In this paper,we present the electric field controllable diffractive optical elements in strontium-barium niobate single crystals with stable tailored spiral-shaped domain structure and demonstrate the generation of optical beam with orbital angular momentum.The required domain pattern was created in the sample with initial domain structure by electric field application using the photolithographically defined liquid electrode.A series of bipolar triangular electric field pulses were applied to the sample for determination of the optimal parameters for complete polarization switching under the electrode.The stable tailored domain pattern of the spiral shape was created by the application of the unipolar pulse of a special shape.The complete switching under the electrode and partial switching under the photoresist layer have been revealed.The imaging by Cherenkov-type second harmonic generation microscopy confirmed that the created domain structure reaches the opposite polar surface.The imaging of the diffraction pattern of the laser beam passing through a voltage-biased DOE confirmed the formation of the beam with orbital angular momentum.The half-wave voltages of 237V and 302 V for wavelength 632.8 nm and 532 nm,respectively,for 2-mmthick sample were measured.The obtained knowledge can be used for the development of domain engineering methods in strontium-barium niobate single crystals for the creation of tailored domain structures for manufacturing of electric field controllablediffractiveoptical elements.
基金supported by a grant from the Russian Science Foundation(No.21-75-10097https://rscf.ru/project/21-75-10097/).
文摘Surface-enhanced Raman spectroscopy(SERS)is a promising analytical method for studying the structure and composition of multi-component media in clinical practice.However,the practical application of SERS imposes several conditions and restrictions depending on the required analytical accuracy and implementation complexity.This paper proposes a simple serum SERS technique for diagnosing multiple myeloma(MM).The process utilises a substrate composed of agglomerated spherical silver particles(~200 nm)with a capillary effect on sodium nitrate crystals(0.02%volume concentration),excited at a wavelength of 785 nm.Spectral characteristics were recorded using a detector without external cooling,ensuring a cost-effective approach.The proposed low-cost approach was tested on 31 samples from MM and 102 serum samples from an age-matched control group.Combining the SERS technique with the multivariate analysis for serum testing provided high discrimination rates for MM patients compared to the control patients,with an average accuracy of over 96%.Biochemical interpretation of the recorded spectra identified the informative bands at 635 cm^(-1),723 cm^(-1),and 1052 cm^(-1).Overall,the proposed SERSbased tool can become the basis for screening for MM and can be easily integrated into clinical practice,expanding diagnostic capabilities where expensive laboratory techniques are not affordable.
基金using the equipment of the Research Educational Center“REC-Vibration Strengthand Reliability of Aerospace Products”with financial support from the Ministry of Science and Higher Education of the Russian Federation(Project No FSSS-2024-0017).
文摘This article presents a device for the storage and gasification of cryogenic working fluid,which is named a cryogenic fuelling tank.A cryogenic fuel tank can serve both as a fuel vessel and a pressure accumulator due to the regasification process that takes place inside.Application of this tank is slowed by the lack of theoretical and experimental research on its working process.This article deals with an investigation of the working process of the energy plant based on a cryogenic fuel tank coupled with a rotor-vane expander.Developed mathematical models include evaporation and condensation processes within the tank,heat exchange between gas chambers and between the tank and environment,and changes in energy due to incoming and leaving mass.Mechanical work used to determine the efficiency of a power plant is generated by a steam expander.Research shows that it is possible to achieve specific work outputs up to 110-160 kJ/kg with relative deviation of power and specific work determination equal to 1.4% and 1.9%correspondingly.
文摘Background:Onchocerciasis(river blindness),caused by the filarial worm speciesOnchocerca volvulus,is a serious vector-borne neglected tropical disease(NTD)of public health and socioeconomic concern.It is transmitted through the bite of black flies of the genusSimulium,and manifested in dermal and ocular lesions.Ninety-nine percent of the total global risk and burden of onchocerciasis is in Africa.This scoping review examines the key challenges related to the elimination of onchocerciasis by 2020-2025 in Africa,and proposes recommendations to overcome the challenges and accelerate disease elimination.To find relevant articles published in peer-reviewed journals,a search of PubMed and Google Scholar databases was carried out.Main text:Rigorous regional interventions carried out to control and eliminate onchocerciasis in the past four decades in Africa have been effective in bringing the disease burden under control;it is currently not a public health problem in most endemic areas.Notably,transmission of the parasite is interrupted in some hyperendemic localities.Recently,there has been a policy shift from control to complete disease elimination by 2020 in selected countries and by 2025 in the majority of endemic African countries.The WHO has published guidelines for stopping mass drug administration(MDA)and verifying the interruption of transmission and elimination of human onchocerciasis.Therefore,countries have revised their plans,established a goal of disease elimination in line with an evidence based decision to stop MDA and verify elimination,and incorporated it into their NTDs national master plans.Nevertheless,challenges remain pertaining to the elimination of onchocerciasis in Africa.The challenge we review in this paper are:incomplete elimination mapping of all transmission zones,co-endemicity of onchocerciasis and loiasis,possible emergence of ivermectin resistance,uncoordinated cross-border elimination efforts,conflict and civil unrest,suboptimal program implementation,and technical and financial challenges.This paper also proposes recommendations to overcome the challenges and accelerate disease elimination.These are:a need for complete disease elimination mapping,a need for collaborative elimination activities between national programs,a need for a different drug distribution approach in conflict-affected areas,a need for routine monitoring and evaluation of MDA programs,a need for implementing alternative treatment strategies(ATSs)in areas with elimination anticipated beyond 2025,and a need for strong partnerships and continued funding.Conclusions:National programs need to regularly monitor and evaluate the performance and progress of their interventions,while envisaging the complete elimination of onchocerciasis from their territory.Factors hindering the targeted goal of interruption of parasite transmission need to be identified and remedial actions should be taken.If possible and appropriate,ATSs need to be implemented to accelerate disease elimination by 2025.
文摘Introduction:Soil is the major reservoir of organic carbon.There is a paucity of soil organic carbon(SOC)stock data of afroalpine and sub-afroalpine vegetation in Ethiopia.Hence,this study was conducted to estimate the SOC stock and correlate it with soil physicochemical properties in Abune Yosef afroalpine and sub-afroalpine vegetation.Systematic sampling was employed to collect soil samples from upper 30 cm.Dry bulk density soil pH(1:2.5 water);organic carbon(Walkley and Black),and total nitrogen(Kjeldahl)were the methods used for soil analysis.Pearson correlation and linear regression analysis were performed in SPSS 24 statistical software.Results:The SOC stock of the study area was found to be 79.57 t C ha−1.Soil organic carbon stock showed statistically significant positive correlation with vegetation type(r=0.522,p<0.01),bulk density(r=0.62,p<0.01),total nitrogen(r=0.41,p<0.01),and altitude(r=0.468,p<0.01)and negative correlation with slope(r=−0.298,p<0.05).The present study revealed similar soil organic carbon stock(SOCS)with the Intergovernmental Panel on Climate Change(IPCC)default estimate for similar regions.Positive correlation of SOCS and altitude could be resulted from the variations in anthropogenic disturbances,temperature,and precipitation vegetation types.The negative correlation between SOCS and slope is the result from the predictably higher soil erosion at steeper slopes.Temporal livestock trampling increased the bulk density but never affected the SOCS to decline.Aspect did not show any significant relationship with SOCS due to either the under surveying of all aspects or similar solar radiation found in the study area.Moreover,gazing,aspect,and soil pH did not show statistically significant impact on SOCS.Conclusion:The SOCS of Abune Yosef afroalpine and sub-afroalpine vegetation is similar to the IPCC default estimate for similar regions.This is a great contribution both to the global and local terrestrial carbon sink.
基金This work is supported by the National Natural Science Foundation of China(Grant No.51872242)the Fundamental Research Funds for the Central Universities(Grant No.D5000200142)+1 种基金Vladislav A.BLATOV thanks the Russian Science Foundation(Grant No.16-13-10158)for support of developing the network topological modelArtem R.OGANOV thanks the Russian Science Foundation(Grant No.19-72-30043).
文摘Although tin monoxide (SnO) is an interesting compound due to its p-type conductivity,a widespread application of SnO has been limited by its narrow band gap of 0.7 eV.In this work,we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals.Our calculations reveal that a metastable SnO (β-SnO),which possesses space group P2_(1)/c and a wide band gap of 1.9 eV,is more stable than α-SnO at pressures higher than 80 GPa.Moreover,a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa.Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa.Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO →α-SnO.Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure.Finally,our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0-9 GPa)through a semiconductor-to-metal transition,while maintaining transparency in the visible light range.
基金V.A.B.,A.A.G.,and A.A.K.thank the Russian Science Foundation(grant No.16-13-10158)for support of developing the network topological modelC.Y.,D.T.,and Q.Z.thank the National Key R&D Program of China(grant No.2017YFB0703200)National Natural Science Foundation of China(grant Nos.51972268,51372203,and 51761135032)for the financial support.We also acknowledge the highperformance computing center of NWPU(China).
文摘The search for new materials requires effective methods for scanning the space of atomic configurations,in which the number is infinite.Here we present an extensive application of a topological network model of solid-state transformations,which enables one to reduce this infinite number to a countable number of the regions corresponding to topologically different crystalline phases.We have used this model to successfully generate carbon allotropes starting from a very restricted set of initial structures;the generation procedure has required only three steps to scan the configuration space around the parents.As a result,we have obtained all known carbon structures within the specified set of restrictions and discovered 224 allotropes with lattice energy ranging in 0.16–1.76 eV atom^(−1) above diamond including a phase,which is denser and probably harder than diamond.We have shown that this phase has a quite different topological structure compared to the hard allotropes from the diamond polytypic series.We have applied the tiling approach to explore the topology of the generated phases in more detail and found that many phases possessing high hardness are built from the tiles confined by six-membered rings.We have computed the mechanical properties for the generated allotropes and found simple dependences between their density,bulk,and shear moduli.
