The present study aims to establish a relationship between serum AMH levels and age in a large group of women living in Bulgaria, as well as to establish reference age-specific AMH levels in women that would serve as ...The present study aims to establish a relationship between serum AMH levels and age in a large group of women living in Bulgaria, as well as to establish reference age-specific AMH levels in women that would serve as an initial estimate of ovarian age. A total of 28,016 women on the territory of the Republic of Bulgaria were tested for serum AMH levels with a median age of 37.0 years (interquartile range 32.0 to 41.0). For women aged 20 - 29 years, the Bulgarian population has relatively high median levels of AMH, similar to women of Asian origin. For women aged 30 - 34 years, our results are comparable to those of women living in Western Europe. For women aged 35 - 39 years, our results are comparable to those of women living in the territory of India and Kenya. For women aged 40 - 44 years, our results were lower than those for women from the Western European and Chinese populations, close to the Indian and higher than Korean and Kenya populations, respectively. Our results for women of Bulgarian origin are also comparable to US Latina women at age 30, 35 and 40 ages. On the base on constructed a statistical model to predicting the decline in AMH levels at different ages, we found non-linear structure of AMH decline for the low AMH 3.5) the dependence of the decline of AMH on age was confirmed as linear. In conclusion, we evaluated the serum level of AMH in Bulgarian women and established age-specific AMH percentile reference values based on a large representative sample. We have developed a prognostic statistical model that can facilitate the application of AMH in clinical practice and the prediction of reproductive capacity and population health.展开更多
Among the macromolecular drug targets in neurodegenerative disorders, the neurotrophin brain-derived neurotrophic factor（BDNF） and its high-affinity tropomyosin-related kinase receptor（Trk B） present strong intere...Among the macromolecular drug targets in neurodegenerative disorders, the neurotrophin brain-derived neurotrophic factor（BDNF） and its high-affinity tropomyosin-related kinase receptor（Trk B） present strong interest for nanomedicine development aiming at neuronal and synaptic repair. Currently, BDNF is regarded as the neurotrophic factor of highest therapeutic significance. However, BDNF has delivery problems as a protein drug. The enhanced activation of the transcription factor CREB（c AMP response element-binding protein） has been evidenced to increase the BDNF gene expression and hence the production of endogenous BDNF. We assume that BDNF delivery by nanocarriers and mitochondrial protection may provide high potential for therapeutic amelioration of the neuroregenerative strategies. Beneficial therapeutic outcomes may be expected for synergistic dual or multi-drug action aiming at（i） neurotrophic protein regulation in the central and peripheral nervous systems, and（ii） diminishment of the production of reactive oxygen species（ROS） and the oxidative damage in mitochondria. Our research strategy is based on a nanoarchitectonics approach for the design of nanomedicine assemblies by hierarchical self-assembly. We explore nanoarchitectonics concepts in soft-matter nanotechnology towards preparation of biodegradable self-assembled lipid nanostructures for safe neuro-therapeutic applications of multi-target nanomedicines.展开更多
Nanocrystals of single-phase samarium monoaluminate (SmAlO3) were synthesized and studied for the first time. Malic acid was employed as a new complexing agent in the sol-gel process. The material was characterized by...Nanocrystals of single-phase samarium monoaluminate (SmAlO3) were synthesized and studied for the first time. Malic acid was employed as a new complexing agent in the sol-gel process. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), specific surface area and density. The lowest size of the nanoparticles was about 50–60 nm and some of them formed agglomerates. The binding energies of core-level electrons of Sm (3d, 4d, 4f, ...展开更多
Recent advances in our understanding of coronavirus disease 2019(COVID-19)and the associated acute respiratory distress syndrome might approximate the cytokine release syndrome of severe immune-mediated disease.Import...Recent advances in our understanding of coronavirus disease 2019(COVID-19)and the associated acute respiratory distress syndrome might approximate the cytokine release syndrome of severe immune-mediated disease.Importantly,this presumption provides the rationale for utilization of therapy,until recently reserved mostly for autoimmune diseases(ADs),in the management of COVID-19 hyperinflammation condition and has led to an extensive discussion for the potential benefits and detriments of immunosuppression.Our paper intends to examine the available recommendations,complexities in diagnosis and management when dealing with patients with ADs amidst the COVID-19 crisis.Mimicking a flare of an underlying AD,overlapping pathological lung patterns,probability of higher rates of false-positive antibody test,and lack of concrete data are only a part of the detrimental and specific characteristics of COVID-19 outbreak among the population with ADs.The administration of pharmaceutical therapy should not undermine the physical and psychological status of the patient with the maximum utilization of telemedicine.Researchers and clinicians should be vigilant for upcoming research for insight and perspective to fine-tune the clinical guidelines and practice and to weigh the potential benefits and detrimental effects of the applied immunomodulating therapy.展开更多
The paper deals with a lossy transmission line terminated at both ends by non-linear RCL elements. The mixed problem for the hyperbolic system, describing the transmission line, to an initial value problem for a neutr...The paper deals with a lossy transmission line terminated at both ends by non-linear RCL elements. The mixed problem for the hyperbolic system, describing the transmission line, to an initial value problem for a neutral equation is reduced. Sufficient conditions for the existence and uniqueness of periodic regimes are formulated. The proof is based on the finding out of suitable operator whose fixed point is a periodic solution of the neutral equation. The method has a good rate of convergence of the successive approximations even for high frequencies.展开更多
A steady-state, rigid-plastic rolling problem for temperature and strain-rate dependent materials with nonlocal friction is considered. A variational formulation is derived, coupling a nonlinear variational inequality...A steady-state, rigid-plastic rolling problem for temperature and strain-rate dependent materials with nonlocal friction is considered. A variational formulation is derived, coupling a nonlinear variational inequality for the velocity and a nonlinear vari- ational equation for the temperature. The existence and uniqueness results are obtained by a proposed fixed point method.展开更多
Photometric observations in Sloan g′and i′bands of four W UMa binaries, V796 Cep,V797 Cep, CSS J015341.9＋381641 and NSVS 3853195, are presented. Our observations showed that CSS J015404.1＋382805 and NSVS 3853195 a...Photometric observations in Sloan g′and i′bands of four W UMa binaries, V796 Cep,V797 Cep, CSS J015341.9＋381641 and NSVS 3853195, are presented. Our observations showed that CSS J015404.1＋382805 and NSVS 3853195 are the same star. We determined the initial epochs T_0 of all targets and found improved values for the period of NSVS 3853195. The light curve solutions of our data revealed that the components of each target are almost the same in terms of mass, temperature,radius and luminosity. The stellar components are G and K spectral types and undergo partial eclipses.All systems have barely-overcontact configurations and can be classified as H subtype W UMa binaries.We established that the relation between the luminosity ratio l_2/l_1 and mass ratio q of our targets is approximately l_2/l_1 = q^（1.5）.展开更多
Photometric observations in Sloan 9＇ and i＇ bands of four W UMa stars, NSVS 2244206, NSVS 908513, CSS J004004.7＋385531 and VSX J062624.4＋570907, are presented. The light curve solutions reveal that all targets hav...Photometric observations in Sloan 9＇ and i＇ bands of four W UMa stars, NSVS 2244206, NSVS 908513, CSS J004004.7＋385531 and VSX J062624.4＋570907, are presented. The light curve solutions reveal that all targets have overcontact configurations with fillout factors within 0.15-0.26. Their components are G-K spectral types and are almost in thermal contact. They are also relatively close in size and luminosity： the radius ratios r2/r1 are within 0.75-0.90; the luminosity ratios 12/11 are within 0.53-0.63. The results of the light curve solution of CSS J004004.7＋385531 imply the weak limb-darkening effect of its primary component and possible presence of additional absorbing features in the system.展开更多
A class of steady-state metal-forming problems,with rigid-plastic,incompressible,strain-rate dependent material model and nonlocal Coulomb’s friction,is considered.Primal,mixed and penalty variational formulations,co...A class of steady-state metal-forming problems,with rigid-plastic,incompressible,strain-rate dependent material model and nonlocal Coulomb’s friction,is considered.Primal,mixed and penalty variational formulations,containing variational inequalities with nonlinear and nondifferentiable terms,are derived and studied.Existence,uniqueness and convergence results are obtained and shortly presented.A priori finite element error estimates are derived and an algorithm,combining the finite element and secant-modulus methods,is utilized to solve an illustrative extrusion problem.展开更多
A class of quasisteady metalforming problems under nonlocal contact and Coulomb＇s friction boundary conditions is considered with an incompressible, rigid plastic, strainrate dependent, isotropic, and kinematic harde...A class of quasisteady metalforming problems under nonlocal contact and Coulomb＇s friction boundary conditions is considered with an incompressible, rigid plastic, strainrate dependent, isotropic, and kinematic hardening material model. A coupled variational formulation is derived, the convergence of a variable stiffness parame ter method with time retardation is proved, and the existence and uniqueness results are obtained.展开更多
Photometric observations in Sloan g′and i′ bands of W UMa binaries NSVS 4340949,T-Dra0–00959,GSC 03950–00707,NSVS 4665041,NSVS 4803568,MM Peg,MM Com and NSVS4751449 are presented.The light curve solutions revealed...Photometric observations in Sloan g′and i′ bands of W UMa binaries NSVS 4340949,T-Dra0–00959,GSC 03950–00707,NSVS 4665041,NSVS 4803568,MM Peg,MM Com and NSVS4751449 are presented.The light curve solutions revealed that the components of each target are of G and K spectral types.The binaries of the sample have middle-contact configurations whose fillout factors are within the range 0.2–0.4.The only exception is NSVS 4751449 which is in deeper contact（fillout factor of 0.55）.It precisely obeys the relation between mass ratio and fillout factor for deep,low mass ratio overcontact binaries.One of the eclipses of almost all targets（except MM Peg）is an occultation and their photometric mass ratios and solutions could be accepted with confidence.We found that the target components have almost equal temperatures but differ considerably in size and mass.The components of the partially-eclipsed MM Peg have close parameters.Our solutions reveal that NSVS 4340949,T-Dra0–00959,NSVS 4803568 and MM Com are of W subtype while GSC 03950–00707,NSVS 4665041,MM Peg and NSVS 4751449 are of A subtype.This subclassification is well-determined for all totallyeclipsed binaries.The targets confirm the trends in which W-subtype systems have smaller periods and lower temperatures than A subtype binaries.展开更多
The transition from empirical and applied approach toward a scientific approach in modem medical disinsection is a result of the discoveries of the organic chemistry. The most intensive used substance in this fteld-D...The transition from empirical and applied approach toward a scientific approach in modem medical disinsection is a result of the discoveries of the organic chemistry. The most intensive used substance in this fteld-DDT （dichlorodiphenyltrichloroethane） is introduced during World War II and contributes to world practical epidemiology just as antibiotics in clinical medicine. However, after the 70s, this substance was placed under a ban, because of the accumulated evidence of many adverse health and environmental impacts globally. Improvement of the insecticides after ＂DDT-era＂ is represented by the introduction of organophosphate and carbamate insecticides in the 1960s. Their broad application is determined by better ecotoxicological characteristics. The advance in biotechnology after the 1980s establishes the new class of insecticides-synthetic pyrethroids. Nowadays they are basic for the insect control. Pyrethroids are characterized by selective impact on insects with much less impact on warm-blooded animals and the environment. Insecticides from the newest class insect growth regulators realize their mode of activity by interfering with chitin metabolism and thus prevent an insect from reaching maturity. These substances have extremely low toxicity, which makes them very promising for the treatment of civilian and military facilities.展开更多
目的:牙槽嵴缺损常会使种植治疗方案复杂化。骨再生的方法有许多种,其中包括引导性骨再生(guided bone regeneration,GBR)。本研究的目的是对当前可获得的应用于种植前或种植同期GBR中的不同类型的膜的相关知识进行总结。膜的主要作用...目的:牙槽嵴缺损常会使种植治疗方案复杂化。骨再生的方法有许多种,其中包括引导性骨再生(guided bone regeneration,GBR)。本研究的目的是对当前可获得的应用于种植前或种植同期GBR中的不同类型的膜的相关知识进行总结。膜的主要作用是阻止上皮细胞和结缔组织细胞进入需要再生的区域,创造和维持多能干细胞及成骨细胞可自由生长的空间。数据来源:对以该主题发表的英文文章进行文献检索。选择了一定数量的研究用以回顾不同类型膜的主要特征,应用和效果。可吸收膜由天然或合成的聚合物制成,如胶原蛋白和脂肪族聚酯。其中,最常使用的是胶原蛋白,它们与牙周结缔组织具有相似的胶原蛋白成分。其他可用的材料有人,猪和牛的心包膜,人羊膜和绒毛膜,以及人脱细胞冻干真皮基质。GBR中使用的不可吸收膜有致密聚四氟乙烯(dense-polytetrafluoroethylene,d-PTFE)膜,膨体聚四氟乙烯(expanded-polytetrafluoroethylene,e-PTFE)膜,钛网和钛加强聚四氟乙烯膜。结论:不可吸收膜最常见的并发症是膜暴露。对这两种类型的膜来说,膜暴露都会对最终骨再生效果产生不利影响。垂直骨增量宜采用不可吸收膜。对于复合骨缺损,两种类型的膜都可获得良好的效果。展开更多
Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface....Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable sources in the manufacture of rubber products. The aim of this work is to investigate the possibilities of using elastomers and ingredients from renewable sources—epoxidized natural rubber, silica obtained by rice husks incineration and microcrystalline cellulose—as fillers and rapeseed oil as a process additive in compositions, intended for the manufacture of soles for winter footwear having an increased coefficient of friction to icy surfaces. The tribological tests based on the coefficient of friction evaluated the adhesion of the composites to the icy surfaces at different temperatures. The complex evaluation of developed composites revealed those containing microcrystalline cellulose and biogenic amorphous silica at a 1:1 ratio as the most suitable for making footwear soles because of the best combination of physicо-mechanical properties and coefficient of friction.展开更多
Plants in natural ecosystems are exposed to a combination of UV radiation,ionizing radiation(IR)and other abiotic factors.These factors change with the altitude.We investigated DNA alterations of some wild plants of d...Plants in natural ecosystems are exposed to a combination of UV radiation,ionizing radiation(IR)and other abiotic factors.These factors change with the altitude.We investigated DNA alterations of some wild plants of different plant families in natural ecosystems at three altitudes in Rila Mountain,Bulgaria(1500,1782,and 2925 m above sea level(a.s.l.)exposed to UV radiation,IR and other abiotic stresses,to assess the tolerance of plant species to the changing environmental conditions in three successive growth seasons.For this purpose,physicochemical,cytogenetic,and molecular methods were applied.DNA damage was assessed by micronucleus test and molecular method comet assay adapted and applied by us to wild plant species from Onagraceae,Rosaceae,Boraginaceae,Saxifragaceae,Orobanchaceae,Asteraceae and Poaceae families,growing at three different altitudes.Variability in the DNA sensitivity and the level of tolerance was observed among the plant species in response to combined abiotic factors assessed by induced DNA damage and gross beta activity.The studied representatives of Poaceae were less susceptible than the other studied species at all three altitudes and showed close level of DNA injuries to that of unaffected control plant grown in laboratory conditions.The lower levels of DNA damage of these wild plant species corresponded to their lower ability to accumulate radionuclides.There was a particularly pronounced low level of DNA injuries in the plant species at the highest altitude.The level of DNA damage showed correlation with the values of some abiotic environmental factors.The results would contribute to the elucidation of the extent of adaptation of plant species to the continuously changing environment and would be useful in selecting sensitive herbaceous monitor species for environmental impact assessment at mountain and alpine sites.展开更多
Recently,we have shown that manual stimulation of paralyzed vibrissal muscles after facial-facial anastomosis reduced the poly-innervation of neuromuscular junctions and restored vibrissal whisking.Using gene knock ou...Recently,we have shown that manual stimulation of paralyzed vibrissal muscles after facial-facial anastomosis reduced the poly-innervation of neuromuscular junctions and restored vibrissal whisking.Using gene knock outs,we found a differential dependence of manual stimulation effects on growth factors.Thus,insulin-like growth factor-1 and brain-derived neurotrophic factor are required to underpin manual stimulation-mediated improvements,whereas FGF-2 is not.The lack of dependence on FGF-2 in mediating these peripheral effects prompted us to look centrally,i.e.within the facial nucleus where increased astrogliosis after facial-facial anastomosis follows ＂synaptic stripping＂.We measured the intensity of Cy3-fluorescence after immunostaining for glial fibrillary acidic protein（GFAP） as an indirect indicator of synaptic coverage of axotomized neurons in the facial nucleus of mice lacking FGF-2（FGF-2^（-/-） mice）.There was no difference in GFAP-Cy3-fluorescence（pixel number,gray value range17-103） between intact wildtype mice（2.12± 0.37×10~7） and their intact FGF-2^（-/-） counterparts（2.12±0.27×10~7） nor after facial-facial anastomosis ＋handling（wildtype：4.06±0.32×10~7;FGF-2^（-/-）：4.39±0.17×10~7）.However,after facial-facial anastomosis,GFAP-Cy3-fluorescence remained elevated in FGF-2^（-/-）-animals（4.54±0.12×10~7）,whereas manual otimulation reduced the intensity of GFAP-immunofluorescence in wild type mice to values that were not significantly different from intact mice（2.63±0.39×10）.We conclude that FGF-2 is not required to underpin the beneficial effects of manual stimulation at the neuro-muscular junction,but it is required to minimize astrogliosis in the brainstem and,by implication,restore synaptic coverage of recovering facial motoneurons.展开更多
文摘The present study aims to establish a relationship between serum AMH levels and age in a large group of women living in Bulgaria, as well as to establish reference age-specific AMH levels in women that would serve as an initial estimate of ovarian age. A total of 28,016 women on the territory of the Republic of Bulgaria were tested for serum AMH levels with a median age of 37.0 years (interquartile range 32.0 to 41.0). For women aged 20 - 29 years, the Bulgarian population has relatively high median levels of AMH, similar to women of Asian origin. For women aged 30 - 34 years, our results are comparable to those of women living in Western Europe. For women aged 35 - 39 years, our results are comparable to those of women living in the territory of India and Kenya. For women aged 40 - 44 years, our results were lower than those for women from the Western European and Chinese populations, close to the Indian and higher than Korean and Kenya populations, respectively. Our results for women of Bulgarian origin are also comparable to US Latina women at age 30, 35 and 40 ages. On the base on constructed a statistical model to predicting the decline in AMH levels at different ages, we found non-linear structure of AMH decline for the low AMH 3.5) the dependence of the decline of AMH on age was confirmed as linear. In conclusion, we evaluated the serum level of AMH in Bulgarian women and established age-specific AMH percentile reference values based on a large representative sample. We have developed a prognostic statistical model that can facilitate the application of AMH in clinical practice and the prediction of reproductive capacity and population health.
基金supported by CNRSsupported by the Czech Science Foundation Grant GACR 17-00973S+1 种基金the projects ELI-Extreme Light Infrastructure–phase 2(CZ.02.1.01/0.0/0.0/15_008/0000162)ELIBIO(CZ.02.1.01/0.0/0.0/15_003/0000447)from the European Regional Development Fund
文摘Among the macromolecular drug targets in neurodegenerative disorders, the neurotrophin brain-derived neurotrophic factor（BDNF） and its high-affinity tropomyosin-related kinase receptor（Trk B） present strong interest for nanomedicine development aiming at neuronal and synaptic repair. Currently, BDNF is regarded as the neurotrophic factor of highest therapeutic significance. However, BDNF has delivery problems as a protein drug. The enhanced activation of the transcription factor CREB（c AMP response element-binding protein） has been evidenced to increase the BDNF gene expression and hence the production of endogenous BDNF. We assume that BDNF delivery by nanocarriers and mitochondrial protection may provide high potential for therapeutic amelioration of the neuroregenerative strategies. Beneficial therapeutic outcomes may be expected for synergistic dual or multi-drug action aiming at（i） neurotrophic protein regulation in the central and peripheral nervous systems, and（ii） diminishment of the production of reactive oxygen species（ROS） and the oxidative damage in mitochondria. Our research strategy is based on a nanoarchitectonics approach for the design of nanomedicine assemblies by hierarchical self-assembly. We explore nanoarchitectonics concepts in soft-matter nanotechnology towards preparation of biodegradable self-assembled lipid nanostructures for safe neuro-therapeutic applications of multi-target nanomedicines.
基金Project supported by University of Food Technologies-Plodiv, Found Science
文摘Nanocrystals of single-phase samarium monoaluminate (SmAlO3) were synthesized and studied for the first time. Malic acid was employed as a new complexing agent in the sol-gel process. The material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), specific surface area and density. The lowest size of the nanoparticles was about 50–60 nm and some of them formed agglomerates. The binding energies of core-level electrons of Sm (3d, 4d, 4f, ...
文摘Recent advances in our understanding of coronavirus disease 2019(COVID-19)and the associated acute respiratory distress syndrome might approximate the cytokine release syndrome of severe immune-mediated disease.Importantly,this presumption provides the rationale for utilization of therapy,until recently reserved mostly for autoimmune diseases(ADs),in the management of COVID-19 hyperinflammation condition and has led to an extensive discussion for the potential benefits and detriments of immunosuppression.Our paper intends to examine the available recommendations,complexities in diagnosis and management when dealing with patients with ADs amidst the COVID-19 crisis.Mimicking a flare of an underlying AD,overlapping pathological lung patterns,probability of higher rates of false-positive antibody test,and lack of concrete data are only a part of the detrimental and specific characteristics of COVID-19 outbreak among the population with ADs.The administration of pharmaceutical therapy should not undermine the physical and psychological status of the patient with the maximum utilization of telemedicine.Researchers and clinicians should be vigilant for upcoming research for insight and perspective to fine-tune the clinical guidelines and practice and to weigh the potential benefits and detrimental effects of the applied immunomodulating therapy.
文摘The paper deals with a lossy transmission line terminated at both ends by non-linear RCL elements. The mixed problem for the hyperbolic system, describing the transmission line, to an initial value problem for a neutral equation is reduced. Sufficient conditions for the existence and uniqueness of periodic regimes are formulated. The proof is based on the finding out of suitable operator whose fixed point is a periodic solution of the neutral equation. The method has a good rate of convergence of the successive approximations even for high frequencies.
文摘A steady-state, rigid-plastic rolling problem for temperature and strain-rate dependent materials with nonlocal friction is considered. A variational formulation is derived, coupling a nonlinear variational inequality for the velocity and a nonlinear vari- ational equation for the temperature. The existence and uniqueness results are obtained by a proposed fixed point method.
基金supported partly by grants ND08/20 and RD 08-102 of the Fund for Scientific Research of the Bulgarian Ministry of Education and Sciencefunded by the National Aeronautics+1 种基金Space Administration and the National Science Foundationsupported partly by funds from project RD 02–81 of Shumen University
文摘Photometric observations in Sloan g′and i′bands of four W UMa binaries, V796 Cep,V797 Cep, CSS J015341.9＋381641 and NSVS 3853195, are presented. Our observations showed that CSS J015404.1＋382805 and NSVS 3853195 are the same star. We determined the initial epochs T_0 of all targets and found improved values for the period of NSVS 3853195. The light curve solutions of our data revealed that the components of each target are almost the same in terms of mass, temperature,radius and luminosity. The stellar components are G and K spectral types and undergo partial eclipses.All systems have barely-overcontact configurations and can be classified as H subtype W UMa binaries.We established that the relation between the luminosity ratio l_2/l_1 and mass ratio q of our targets is approximately l_2/l_1 = q^（1.5）.
基金supported partly by funds of project RD 08-244 of Scientific Foundation of Shumen Universitythe AAVSO Photometric All-Sky Survey(APASS),funded by the Robert Martin Ayers Sciences Fund
文摘Photometric observations in Sloan 9＇ and i＇ bands of four W UMa stars, NSVS 2244206, NSVS 908513, CSS J004004.7＋385531 and VSX J062624.4＋570907, are presented. The light curve solutions reveal that all targets have overcontact configurations with fillout factors within 0.15-0.26. Their components are G-K spectral types and are almost in thermal contact. They are also relatively close in size and luminosity： the radius ratios r2/r1 are within 0.75-0.90; the luminosity ratios 12/11 are within 0.53-0.63. The results of the light curve solution of CSS J004004.7＋385531 imply the weak limb-darkening effect of its primary component and possible presence of additional absorbing features in the system.
文摘A class of steady-state metal-forming problems,with rigid-plastic,incompressible,strain-rate dependent material model and nonlocal Coulomb’s friction,is considered.Primal,mixed and penalty variational formulations,containing variational inequalities with nonlinear and nondifferentiable terms,are derived and studied.Existence,uniqueness and convergence results are obtained and shortly presented.A priori finite element error estimates are derived and an algorithm,combining the finite element and secant-modulus methods,is utilized to solve an illustrative extrusion problem.
文摘A class of quasisteady metalforming problems under nonlocal contact and Coulomb＇s friction boundary conditions is considered with an incompressible, rigid plastic, strainrate dependent, isotropic, and kinematic hardening material model. A coupled variational formulation is derived, the convergence of a variable stiffness parame ter method with time retardation is proved, and the existence and uniqueness results are obtained.
基金supported partly by project DN08/20 of the Scientific Foundation of the Bulgarian Ministry of EducationScience as well as by project RD 02-102 of Shumen University+1 种基金project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technologyfunded by the National Aeronautics and Space Administration and the National Science Foundation
文摘Photometric observations in Sloan g′and i′ bands of W UMa binaries NSVS 4340949,T-Dra0–00959,GSC 03950–00707,NSVS 4665041,NSVS 4803568,MM Peg,MM Com and NSVS4751449 are presented.The light curve solutions revealed that the components of each target are of G and K spectral types.The binaries of the sample have middle-contact configurations whose fillout factors are within the range 0.2–0.4.The only exception is NSVS 4751449 which is in deeper contact（fillout factor of 0.55）.It precisely obeys the relation between mass ratio and fillout factor for deep,low mass ratio overcontact binaries.One of the eclipses of almost all targets（except MM Peg）is an occultation and their photometric mass ratios and solutions could be accepted with confidence.We found that the target components have almost equal temperatures but differ considerably in size and mass.The components of the partially-eclipsed MM Peg have close parameters.Our solutions reveal that NSVS 4340949,T-Dra0–00959,NSVS 4803568 and MM Com are of W subtype while GSC 03950–00707,NSVS 4665041,MM Peg and NSVS 4751449 are of A subtype.This subclassification is well-determined for all totallyeclipsed binaries.The targets confirm the trends in which W-subtype systems have smaller periods and lower temperatures than A subtype binaries.
文摘The transition from empirical and applied approach toward a scientific approach in modem medical disinsection is a result of the discoveries of the organic chemistry. The most intensive used substance in this fteld-DDT （dichlorodiphenyltrichloroethane） is introduced during World War II and contributes to world practical epidemiology just as antibiotics in clinical medicine. However, after the 70s, this substance was placed under a ban, because of the accumulated evidence of many adverse health and environmental impacts globally. Improvement of the insecticides after ＂DDT-era＂ is represented by the introduction of organophosphate and carbamate insecticides in the 1960s. Their broad application is determined by better ecotoxicological characteristics. The advance in biotechnology after the 1980s establishes the new class of insecticides-synthetic pyrethroids. Nowadays they are basic for the insect control. Pyrethroids are characterized by selective impact on insects with much less impact on warm-blooded animals and the environment. Insecticides from the newest class insect growth regulators realize their mode of activity by interfering with chitin metabolism and thus prevent an insect from reaching maturity. These substances have extremely low toxicity, which makes them very promising for the treatment of civilian and military facilities.
文摘目的:牙槽嵴缺损常会使种植治疗方案复杂化。骨再生的方法有许多种,其中包括引导性骨再生(guided bone regeneration,GBR)。本研究的目的是对当前可获得的应用于种植前或种植同期GBR中的不同类型的膜的相关知识进行总结。膜的主要作用是阻止上皮细胞和结缔组织细胞进入需要再生的区域,创造和维持多能干细胞及成骨细胞可自由生长的空间。数据来源:对以该主题发表的英文文章进行文献检索。选择了一定数量的研究用以回顾不同类型膜的主要特征,应用和效果。可吸收膜由天然或合成的聚合物制成,如胶原蛋白和脂肪族聚酯。其中,最常使用的是胶原蛋白,它们与牙周结缔组织具有相似的胶原蛋白成分。其他可用的材料有人,猪和牛的心包膜,人羊膜和绒毛膜,以及人脱细胞冻干真皮基质。GBR中使用的不可吸收膜有致密聚四氟乙烯(dense-polytetrafluoroethylene,d-PTFE)膜,膨体聚四氟乙烯(expanded-polytetrafluoroethylene,e-PTFE)膜,钛网和钛加强聚四氟乙烯膜。结论:不可吸收膜最常见的并发症是膜暴露。对这两种类型的膜来说,膜暴露都会对最终骨再生效果产生不利影响。垂直骨增量宜采用不可吸收膜。对于复合骨缺损,两种类型的膜都可获得良好的效果。
文摘Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable sources in the manufacture of rubber products. The aim of this work is to investigate the possibilities of using elastomers and ingredients from renewable sources—epoxidized natural rubber, silica obtained by rice husks incineration and microcrystalline cellulose—as fillers and rapeseed oil as a process additive in compositions, intended for the manufacture of soles for winter footwear having an increased coefficient of friction to icy surfaces. The tribological tests based on the coefficient of friction evaluated the adhesion of the composites to the icy surfaces at different temperatures. The complex evaluation of developed composites revealed those containing microcrystalline cellulose and biogenic amorphous silica at a 1:1 ratio as the most suitable for making footwear soles because of the best combination of physicо-mechanical properties and coefficient of friction.
基金This work was supported by a grant of the National Science Fund of the Republic of Bulgaria under Project No.DN 04/1,13.12.2016 entitled:“Study of the combined effect of the natural radioactivity background,the UV radiation,the climate changes and the cosmic rays on model groups of plant and animal organisms in mountain ecosystems”.
文摘Plants in natural ecosystems are exposed to a combination of UV radiation,ionizing radiation(IR)and other abiotic factors.These factors change with the altitude.We investigated DNA alterations of some wild plants of different plant families in natural ecosystems at three altitudes in Rila Mountain,Bulgaria(1500,1782,and 2925 m above sea level(a.s.l.)exposed to UV radiation,IR and other abiotic stresses,to assess the tolerance of plant species to the changing environmental conditions in three successive growth seasons.For this purpose,physicochemical,cytogenetic,and molecular methods were applied.DNA damage was assessed by micronucleus test and molecular method comet assay adapted and applied by us to wild plant species from Onagraceae,Rosaceae,Boraginaceae,Saxifragaceae,Orobanchaceae,Asteraceae and Poaceae families,growing at three different altitudes.Variability in the DNA sensitivity and the level of tolerance was observed among the plant species in response to combined abiotic factors assessed by induced DNA damage and gross beta activity.The studied representatives of Poaceae were less susceptible than the other studied species at all three altitudes and showed close level of DNA injuries to that of unaffected control plant grown in laboratory conditions.The lower levels of DNA damage of these wild plant species corresponded to their lower ability to accumulate radionuclides.There was a particularly pronounced low level of DNA injuries in the plant species at the highest altitude.The level of DNA damage showed correlation with the values of some abiotic environmental factors.The results would contribute to the elucidation of the extent of adaptation of plant species to the continuously changing environment and would be useful in selecting sensitive herbaceous monitor species for environmental impact assessment at mountain and alpine sites.
基金financially supported by the Koln Fortune Programmthe Jean-Uhrmacher FoundationAkdeniz University Research Fund
文摘Recently,we have shown that manual stimulation of paralyzed vibrissal muscles after facial-facial anastomosis reduced the poly-innervation of neuromuscular junctions and restored vibrissal whisking.Using gene knock outs,we found a differential dependence of manual stimulation effects on growth factors.Thus,insulin-like growth factor-1 and brain-derived neurotrophic factor are required to underpin manual stimulation-mediated improvements,whereas FGF-2 is not.The lack of dependence on FGF-2 in mediating these peripheral effects prompted us to look centrally,i.e.within the facial nucleus where increased astrogliosis after facial-facial anastomosis follows ＂synaptic stripping＂.We measured the intensity of Cy3-fluorescence after immunostaining for glial fibrillary acidic protein（GFAP） as an indirect indicator of synaptic coverage of axotomized neurons in the facial nucleus of mice lacking FGF-2（FGF-2^（-/-） mice）.There was no difference in GFAP-Cy3-fluorescence（pixel number,gray value range17-103） between intact wildtype mice（2.12± 0.37×10~7） and their intact FGF-2^（-/-） counterparts（2.12±0.27×10~7） nor after facial-facial anastomosis ＋handling（wildtype：4.06±0.32×10~7;FGF-2^（-/-）：4.39±0.17×10~7）.However,after facial-facial anastomosis,GFAP-Cy3-fluorescence remained elevated in FGF-2^（-/-）-animals（4.54±0.12×10~7）,whereas manual otimulation reduced the intensity of GFAP-immunofluorescence in wild type mice to values that were not significantly different from intact mice（2.63±0.39×10）.We conclude that FGF-2 is not required to underpin the beneficial effects of manual stimulation at the neuro-muscular junction,but it is required to minimize astrogliosis in the brainstem and,by implication,restore synaptic coverage of recovering facial motoneurons.
