190 research outputs found
Spin-polarized electronic structure of the core-shell ZnO/ZnO:Mn nanowires probed by x-ray absorption and emission spectroscopy
The combination of x-ray spectroscopy methods complemented with theoretical
analysis unravels the coexistence of paramagnetic and antiferromagnetic phases
in the Zn_0.9Mn_0.1O shell deposited onto array of wurtzite ZnO nanowires. The
shell is crystalline with orientation toward the ZnO growth axis, as
demonstrated by X-ray linear dichroism. EXAFS analysis confirmed that more than
90% of Mn atoms substituted Zn in the shell while fraction of secondary phases
was below 10%. The value of manganese spin magnetic moment was estimated from
the Mn K{\beta} X-ray emission spectroscopy to be 4.3{\mu}B which is close to
the theoretical value for substitutional Mn_Zn. However the analysis of L_2,3
x-ray magnetic circular dichroism data showed paramagnetic behaviour with
saturated spin magnetic moment value of 1.95{\mu}B as determined directly from
the spin sum rule. After quantitative analysis employing atomic multiplet
simulations such difference was explained by a coexistence of paramagnetic
phase and local antiferromagnetic coupling of Mn magnetic moments. Finally,
spin-polarized electron density of states was probed by the spin-resolved Mn
K-edge XANES spectroscopy and consequently analyzed by band structure
calculations.Comment: Supplementary information available at
http://www.rsc.org/suppdata/ja/c3/c3ja50153a/c3ja50153a.pdf J. Anal. At.
Spectrom., 201
Differences in behavior and distribution of permafrost-related lakes in Central Yakutia and their response to climatic drivers
The Central Yakutian permafrost landscape is rapidly being modified by land use and global warming, but small-scale thermokarst process variability and hydrological conditions are poorly understood. We analyze lake-area changes and thaw subsidence of young thermokarst lakes on ice-complex deposits (yedoma lakes) in comparison to residual lakes in alas basins during the last 70 years for a local study site and we record regional lake size and distribution on different ice-rich permafrost terraces using satellite and historical airborne imagery. Statistical analysis of climatic and ground-temperature data identified driving factors of yedoma- and alas-lake changes. Overall, lake area is larger today than in 1944 but alas-lake levels have oscillated greatly over 70 years, with a mean alas-lake-radius change rate of 1.663.0 m/yr. Anthropogenic
disturbance and forest degradation initiated, and climate forced rapid, continuous yedoma-lake growth. The mean yedoma lake-radius change rate equals 1.261.0 m/yr over the whole observation period.
Mean thaw subsidence below yedoma lakes is 6.261.4 cm/yr. Multiple regression analysis suggests that winter precipitation, winter temperature, and active-layer properties are primary controllers of area changes in both lake types; summer weather and permafrost conditions additionally influence yedoma-lake growth rates. The main controlling factors of alas-lake changes are unclear due to larger catchment areas and subsurface hydrological conditions. Increasing thermokarst activity is currently linked to older terraces with higher ground-ice contents, but thermokarst activity will likely stay high and wet conditions will persist within the near future in Central Yakutian alas basins
STUDY THE POSSIBILITY OF MODELING OF THE CUTTING PROCESS IN THE CHAMBER FOR CRUSHING FRUIT AND VEGETABLES
The grinding process of fruits and vegetables in the preparation of juice with pulp, usually carried out by means juicers, blenders or grinders with a relatively slowly rotating blades and stationary gratings with a continuous flow of raw materials. Intensification of processes of division of the products of the conversion will asunder allow sharply duration and raise the uniformity of the processing cheese that will say on quality ready drink as a whole. The interaction of the blade and material is characterized effort of the cutting moreover the general power, acting on blade on the part of material, is not found in planes of the cutting in consequence of which on blade of the knife, alongside with vertical, acts and horizontal forming power. Horizontal form to deform (change) sidebar cut-ting edge of the knife in consequence of which in general event provision to necessary acerbity in flat material requires increase of his(its) thickness and using the additional relationships (the jumper). It is installed that values of magnitude of deformation and speed of its extending are connected among themselves through the parameters characterizing pressure and plasticity of medium of installation of machining. Hence, speed depends on properties of a body in which the pulse is passed round. In the majority of materials speed of extending of a pulse appears an order of 5 103 km/s. Accounting of received data in the determination of rational cutting speeds for different materials with elastoplastic properties (approximation cutting speed for the propagation velocity of deformation) will allow to reduce pre-separation deformation and, respectively, spent on her work, localization stress under cutting edge, and, as consequence will lead to higher product yield and improve the purity of the slices. Improving the quality cutting may be associated with an increase of inertia of the structural elements of the material (fibers) by increasing the speed of the process
HPV-associated cervical cancer: Current status and prospects
Every year, 570,000 new cases of cervical cancer (CC) are diagnosed in the world, and 311,000 people die from this disease. CC is the fourth most common type of cancer and therefore the fourth leading cause of cancer death in women worldwide. Numerous data on the occurrence and development of cervical cancer indicate an association in most cases (up to 90 %) with human papillomaviruses (HPV) of high carcinogenic risk (HCR).CC prevention strategies are based on screening, and deaths from this oncopathology can be prevented through vaccination and treatment with early detection of the disease.In this review, much attention is paid to current issues of detection and prevention of HPV-associated pathologies, and cervical cancer in particular, aiming to summarize and analyze the latest international literature data on this issue. As a result of this study, it was shown that for countries implementing the National program of vaccination against HPV of high carcinogenic risk, a decrease in the incidence of both cervical pathologies of varying severity and other cancers associated with the HPV carriage was registered.While effective implementation of actual experience and future advances in human papillomavirus vaccine prophylaxis may make it possible for all countries to move to the high levels of vaccination coverage required to eliminate HPV-associated pathologies, the results also suggest that the path to complete cervical cancer elimination as a global public health problem can be extremely difficult due to a number of existing limitations
Resilience to orthostasis and haemorrhage: A pilot study of common genetic and conditioning mechanisms
A major challenge presently is not only to identify the genetic polymorphisms increasing risk to diseases, but to also find out factors and mechanisms, which can counteract a risk genotype by developing a resilient phenotype. The objective of this study was to examine acquired and innate vagal mechanisms that protect against physical challenges and haemorrhages in 19 athletes and 61 non-athletes. These include examining change in heart rate variability (HF-HRV; an indicator of vagus activity) in response to orthostatic challenge, platelet count (PLT), mean platelet volume (MPV), and single-nucleotide polymorphisms in genes that encode several coagulation factors, PAI-1, and MTHFR. Individual differences in PLT and MPV were significant predictors, with opposite effects, of the profiles of the HF-HRV changes in response to orthostasis. Regular physical training of athletes indirectly (through MPV) modifies the genetic predisposing effects of some haemostatic factors (PAI-1 and MTHFR) on vagal tone and reactivity. Individual differences in vagal tone were also associated with relationships between Factor 12 C46T and Factor 11 C22771T genes polymorphisms. This study showed that genetic predispositions for coagulation are modifiable. Its potential significance is promoting advanced protection against haemorrhages in a variety of traumas and injuries, especially in individuals with coagulation deficits
Circulating Ouabain Modulates Expression of Claudins in Rat Intestine and Cerebral Blood Vessels
The ability of exogenous low ouabain concentrations to affect claudin expression and therefore epithelial barrier properties was demonstrated previously in cultured cell studies. We hypothesized that chronic elevation of circulating ouabain in vivo can affect the expression of claudins and tight junction permeability in different tissues. We tested this hypothesis in rats intraperitoneally injected with ouabain (1 μg/kg) for 4 days. Rat jejunum, colon and brain frontal lobes, which are variable in the expressed claudins and tight junction permeability, were examined. Moreover, the porcine jejunum cell line IPEC-J2 was studied. In IPEC-J2-cells, ouabain (10 nM, 19 days of incubation) stimulated epithelial barrier formation, increased transepithelial resistance and the level of cSrc-kinase activation by phosphorylation, accompanied with an increased expression of claudin-1, -5 and down-regulation of claudin-12; the expression of claudin-3, -4, -8 and tricellulin was not changed. In the jejunum, chronic ouabain increased the expression of claudin-1, -3 and -5 without an effect on claudin-2 and -4 expression. In the colon, only down-regulation of claudin-3 was observed. Chronic ouabain protected the intestine transepithelial resistance against functional injury induced by lipopolysaccharide treatment or by modeled acute microgravity; this regulation was most pronounced in the jejunum. Claudin-1 was also up-regulated in cerebral blood vessels. This was associated with reduction of claudin-3 expression while the expression of claudin-5 and occludin was not affected. Altogether, our results confirm that circulating ouabain can functionally and tissue-specifically affect barrier properties of epithelial and endothelial tissues via Na,K-ATPase-mediated modulation of claudins expression
Endometrial Infertility in Patients of Late Reproductive age (a review)
Background. Endometrial infertility is a frequent cause of failure in assisted reproduction. Causes of endometrial infertility are manifold and require comprehensive assessment for a successful choice of treatment strategy.Objectives. A review of infertility concepts accounting for endometrial infertility in women of late reproductive age.Methods. Bibliographic analysis: sources for review were mined in the PubMed, MedLine, eLibrary and Cyberleninka databases at a depth of 10 years. Keyword queries were: endometrial factors of infertility, uterine infertility [маточные факторы бесплодия], causes of infertility. Selected articles related to female infertility and, particularly, endometrial factors of infertility. Low-informative articles were not considered.Results. A total of 51 sources were analysed, with 36 selected in the review. The reviewed evidence suggests that endometrial female infertility in late reproductive age is associated with cumulative gynaecological pathology and age-related change adversely impacting endometrial receptivity and synchrony with embryo maturation in assisted reproductive protocols.Conclusion. Determining the functional status of endometrium is prerequisite for the outcome prognosis in assisted reproduction due to feasible failures to conceive with a vital embryo but reduced endometrial receptivity. This observation warrants a timely diagnosis and treatment of endometrial disorders prior to having assisted reproductive interventions. Woman’s age is the main predictor of successful pregnancy in IVF/ICSI protocols. Among the main markers of successful implantation is endometrial thickness. Uterine infertility may relate to impaired local immunity and autoimmune responses in uterine cavity. The most common mechanisms of uterine infertility are associated uterine myoma, endometriosis and endometritis. Women with uterine infertility attempting IVF/ICSI procedures often exhibit asynchronous endometrial development relative to the embryo maturity for implantation
SOMATIC AND REPRODUCTIVE HEALTH PATTERNS IN CHILDREN AND ADOLESCENTS FROM TOFALARIA
We present the data on physical development, somatic pathology, reproductive disorders in children and teenagers from Tofalaria. Medical documentation and reports were analyzed, specialized surveys of children and teenagers by pediatricians, endocrinologist, gynecologist were carried out. Microscopy, oncocytology, PCR for detection sexually transmitted diseases (chlamidia, mycoplasma papillomavirus 16,18) and colposcopy were done in all teenaged girls. Evaluated morbidity was high. In indigenous Tofalaria population we found significant differences in rates of skeletal and conjunctive tissue disorders (incorrect posture, scoliosis, flatfoot) as well as endocrine disorders and nutrition (incorrect puberty, diffuse nontoxic goiter, growth retardation, hypotrophy). Reproductive health of girls in Tofalaria is characterized by early start of sexual activity, high number of abortion and high STD level and cervix condition is characterized by high rate of columnar epithelium ectopia to an ectocervix with often combination with inflammation. We suppose this situation as a consequences of its reproductive behavior. We believe that the target, long term program of educational, prophylactic and treatment efforts is needed to be developed for preservation of children and teenagers health in Tofalaria
HORMONEMEDIATED REGULATION OF CYTOKINES IN PATIENTS WITH ADENOMYOSIS AND UNSUCCESSFUL IVF ATTEMPTS
Aim. The study was to evaluate the effect of cytokine dysfunctions on the endometrial implantation potential in patients with adenomyosis and unsuccessful IVF attempts and the possibility of hormone-mediated regulation of the cytokine balance at the pre-gravitational stage. Materials and methods. The study included 90 patients with infertility, an unsuccessful attempt of IVF in the history and diffuse adenomyosis of 1 or 2 degrees. Patients were randomized into two groups: the 1st group consisted of 44 patients (group 1) − no pre-education training was conducted. The second group − 46 patients − pregravid preparation of dienogest (2 mg daily for 3 months before the IVF cycle). Control group (group 3) − 30 healthy fertile women. To assess the implantation potential of the endometrium, initially, and after pre-gravity training, the concentration of LIF, IL1в, IL-6, IL-10, RAIL in cervical mucus was determined.Results. Analysis of the indices in patients with adenomyosis showed a decrease in their implantation potential of the endometrium. It has been revealed that hormone-modulating therapy with dienogest partially neutralizes cytokine regulation defects and leads to a certain increase in the effectiveness of IVF programs.Conclusion. Shows expediency of including dienogest in the pregravide preparation plan for patients with adenomyosis, but for full immunocorrection in pregravidual training in women with adenomyosis 1 and 2 The degree of additional directional immunotropic therapy is probably necessary
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