Linear and planar molecules formed by coupled P donors in silicon

Using the effective mass theory and the multi-valley envelope function representation, we have developed a theoretical framework for computing the single-electron electronic structure of several phosphorus donors interacting in an arbitrary geometrical configuration in silicon taking into account the valley-orbit coupling. The methodology is applied to three coupled phosphorus donors, arranged in a linear chain and in a triangle, and to six donors arranged in a regular hexagon. The results of the simulations evidence that the valley composition of the single-electron states strongly depends on the geometry of the dopant molecule and its orientation relative to the crystallographic axes of silicon. The electron binding energy of the triatomic linear molecules is larger than that of the diatomic molecule oriented along the same crystallographic axis, but the energy gap between the ground state and the first excited state is not significantly different for internuclear distances from 1.5 to 6.6 nm. Three donor atoms arranged in a triangle geometry have larger binding energies than a triatomic linear chain of dopants with the same internuclear distances. The planar donor molecules are characterized by a strong polarization in favor of the valleys oriented perpendicular to the plane of the molecule. The polarization increases with number of atoms forming the planar molecule

The теoretical aspects of concepts and components of enterprise

Систематизовано кілька концепцій розвитку підприємства. Визначено елементи (складові) визначення розвитку підприємства.The article presents several concepts of enterprise development. The paper defines the elements (components) of the definition of enterprise development

Human papillomavirus E2 regulates SRSF3 (SRp20) to promote capsid protein expression in infected differentiated keratinocytes

The human papillomavirus (HPV) life cycle is tightly linked to differentiation of the infected epithelial cell suggesting a sophisticated interplay between host cell metabolism and virus replication. Previously we demonstrated in differentiated keratinocytes in vitro and in vivo that HPV16 infection caused increased levels of the cellular SR splicing factors (SRSFs) SRSF1 (ASF/SF2), SRSF2 (SC35) and SRSF3 (SRp20). Moreover, the viral E2 transcription and replication factor that is expressed at high levels in differentiating keratinocytes could bind and control activity of the SRSF1 gene promoter. Here we reveal that E2 proteins of HPV16 and HPV31 control expression of SRSFs 1, 2 and 3 in a differentiation-dependent manner. E2 has the greatest trans-activation effect on expression of SRSF3. siRNA depletion experiments in two different models of the HPV16 life cycle (W12E and NIKS16) and one model of the HPV31 life cycle (CIN612-9E) revealed that only SRSF3 contributed significantly to regulation of late events in the virus life cycle. Increased levels of SRSF3 are required for L1 mRNA and capsid protein expression. Capsid protein expression was regulated specifically by SRSF3 and appeared independent of other SRSFs. Taken together these data suggest a significant role of the HPV E2 protein in regulating late events in the HPV life cycle through transcriptional regulation of SRSF3 expression. IMPORTANCE Human papillomavirus replication is accomplished in concert with differentiation of the infected epithelium. Virus capsid protein expression is confined to the upper epithelial layers so as to avoid immune detection. In this study we demonstrate that the viral E2 transcription factor activates the promoter of the cellular SRSF3 RNA processing factor. SRSF3 is required for expression of the E4̂L1 mRNA and so controls expression of the HPV L1 capsid protein. Thus we reveal a new dimension of virus-host interaction crucial for production of infectious virus. SRSF proteins are known drug targets. Therefore, this study provides an excellent basis for developing strategies to regulate capsid protein production in the infected epithelium and production of new virions

Assessing significance of peripheral blood indicators for differential diagnosis and prognosis of thrombotic complications in polycythemia vera and secondary erythrocytosis.

The aim of the study – determining of changes in peripheral blood (PB) in patients with secondary erythrocytosis (SE) and polycythemia vera (PV), detection of discriminatory parameters levels of PB indicators and analyzing of their operating characteristics for differentiation of erythrocytosis and predicting of thrombotic events in patients with PV. Materials and methods. The material for the study was the results of clinical trials of 210 patients with erythrocytosis who underwent differential diagnosis between PV and SE. Results and discussion. The optimal threshold for differential diagnosis of red blood cells content between PV and SE is >6.08•1012/ L, the diagnostic value of the marker equals to the level of a good diagnostic marker (AUC=0.82; 95% CI=0.77-0.87, p <0.0001). Hematocrit threshold is >57.5% with its capacity – 0.72 (0.66-0.78, p <0.0001), that corresponds to the level of a middle diagnostic marker. The most pathognomonic section of white blood cells (WBC) to differentiate erythrocytosis is >8.9•109/L, and the boundary of marker is consistent with a good level of efficiency (AUC=0.79, 95% CI=0.72-0.84, p<0.0001). The efficiency criterion "platelets >287•109 /L" to differentiate erythrocytosis is 0.90 (0.86-0.94, p <0.0001).The predicting effectiveness of cardiovascular events with help of criterion "hematocrit >55%" and "WBC >12.3•109 /L", according to the AUC (AUC=0.65; 95% CI=0.52-0.79, p=0.021 and AUC=0.66; 95% CI=0.55-0.77, p=0.003, respectively), corresponds to the average power level. Conclusion. Hemoglobin has not confirmed its value for the differential diagnosis between PV and SE. Using other parameters of PB with the aim of differentiating PV and SE is rational, but their discriminatory power levels greatly depend on the group erythrocytosis. In our cohort were obtained the following most appropriate criteria for inclusion of patients in the group of patients with PV: "WBC >8.9•109/L", "red blood cells >6.08•1012/L" and "hematocrit >57.5%". The most significant marker of general clinical blood test to differentiate between PV and SE is "platelets >287•109/L". Hematocrit over 55% and WBC over 12.3·109/L are valuable prognostic markers of thrombosis in PV patients, but their use is appropriate only in a cohort of patients with PV without classical factors of cardiovascular events

ВИВЧЕННЯ СИНДРОМУ ПСИХОЕМОЦІЙНОГО ВИГОРАННЯ У ПРЕДСТАВНИКІВ РІЗНИХ ПРОФЕСІЙНИХ ГРУП

In the article we provide a comparative analysis of the results of experiment that was carried out with proved hypothesis: the emergence of a syndrome of "professional burnout" occurs more often in specialists who belong to a professional group of health professionals. The results showed that the degree of syndrome formation in the professional group of health professionals is higher than among the teachers.У статті проведено порівняльний аналіз результатів дослідно-експериментальної роботи та доведено гіпотезу дослідження: виникнення синдрому професійного вигорання частіше виникає у спеціалістів, які належать до професійної групи медичних працівників. Результати показали, що ступінь сформованості синдрому психоемоційного вигорання в професійній групі медичних працівників вищий, ніж серед педагогів: педагоги – 415 балів, медичні працівники – 490 балів

Excitons and singlet fission at hybrid inorganic-organic semiconductor interfaces

Excitons in organic crystalline semiconductors play a crucial role in the operation of optoelectronic devices such as organic solar cells, light-emitting diodes, and photodetectors. The excitonic properties of materials are dramatically affected by the presence of surfaces and interfaces. In this work, we investigate the influence of a neutral hydrogen-passivated 1x2 reconstructed (100) silicon substrate on excitons within the crystalline tetracene layer deposited on the top of it. Our findings reveal that singlet excitons in the contact tetracene layer are situated within the continuum of unbound Wannier-Mott excitonic states in silicon, with noteworthy hybridization between these states. Consequently, in the contact tetracene layer, all singlet excitons exhibit a pronounced interlayer charge transfer character, while the triplet exciton remains confined to the tetracene layer. This makes the singlet fission effect highly improbable for the contact tetracene layer. Additionally, the presence of the silicon substrate results in a modification of the singlet-triplet gap by 144 meV. This change is solely attributed to the hybridization with excitons in silicon, which influences the exchange energy. Our results show that the dynamic dielectric screening caused by the substrate does not impact the singlet-triplet gap but alters the exciton binding energies.Comment: 26 pages, 7 figure

Comparison of risk assessment models of BRCA1 and BRCA2 mutation carrier in patients with breast cancer.

Analysis of efficiency of the algorithm BOADICEA using and Manchester scoring system to predict the carrier of BRCA1 and BRCA2 mutations in Ukranian patients with breast cancer was performed. Materials for this study were the results of clinical, imunogistological, pathogistological, genealogical, molecular genetic researches of 146 patients with breast cancer. Calculations of mutations risk were performed using BOADICEA algorithm and Manchester scoring system. In the total group of patients the area under the curve while predicting BRCA1 mutations with algorithm BOADICEA was 0.86, with Manchester scoring system - 0.84, and in calculation of the combined risk of BRCA mutations - 0.83 and 0.84, respectively. However, statistical difference between the areas of algorithms has not been established (p> 0.05), it indicates to the same discriminatory power of the test models. Better sensitivity, specificity, positive and negative predictive value of results of BOADICEA algorithm was reached in 6% of BRCA1 probability and in 8% threshold of BRCA1/2 mutations. The Manchester scoring system has showed the best operating characteristics with 6 and 13-point probability of BRCA1 and BRCA1/2 mutations respectively. Patients with probability of mutations with such thresholds may be offered molecular study of pathogenic alleles

INVESTIGATIONS OF THE DYNAMICS OF A BISTABLE ELECTROMAGNET WITH IMPROVED CHARACTERISTICS FOR MEDIUM VOLTAGE VACUUM CIRCUIT BREAKERS

Introduction. Currently, for switching medium voltage circuits, vacuum circuit breakers are widely used, which have good arcing properties and high breaking capacity. One of the problems of creating the drive mechanism of such apparatus is the need to ensure the absence of contact welding when a through current of a short circuit of a given duration flows through them, which is achieved due to a certain amount of contact pressure. One of the problems arising in the design of circuit breakers is the need to fix the mechanism with a mechanical lock, which should hold the mechanism securely. This leads to significant specific mechanical loads, which in turn reduces the reliability of the circuit breaker. One way to solve these problems is to create a drive based on monostable or bistable electromagnetic actuators with highly coercive permanent magnets, which provide reliable fixation of the position of the contacts. Purpose. Investigation of the improved design of a bistable electromagnetic actuator based on permanent magnets of a medium voltage vacuum circuit breaker. Methods. Theoretical and experimental research and comparative analysis of existing and developed electromagnetic actuators. Conclusions. A new design of an electromagnetic bistable actuator with reduced overall dimensions is developed and tested. The electromechanical characteristics of the actuator correspond to the technical specifications, which is confirmed by both theoretical and experimental studies. The proposed actuator can be used as a drive mechanism for medium voltage vacuum circuit breakers.В статье исследован новый бистабильный электромагнит с высококоэрцитивными постоянными магнитами, который предполагается использовать в качестве актуатора вакуумных выключателей средних напряжений. Приводится теоретическое и экспериментальное исследование усовершенствованной конструкции электромагнита с целью сравнительного анализа его параметров с параметрами имеющейся конструкции. Теоретическое исследование базируется на мультифизической модели, которая включает расчет статического и динамического электромагнитных полей в нелинейной проводящей неоднородной среде с учетом постоянных магнитов, нелинейных уравнений разрядной цепи накопительного конденсатора, нелинейных уравнений движения. Экспериментальные исследования, которые проводились на реальном вакуумном выключателе, показали соответствие параметров нового бистабильного электромагнита расчетным показателям. Направление дальнейших исследований представляются в виде оптимизации геометрии электромагнита и схемы управления

Вміст важких металів у коров’ячому молоці-сировині Полтавського району (Україна)

The concentration of heavy metals (Pb, Cd, Cu, As, Zn, Hg) in cow milk-raw materials was detected on the territory of the Poltava district (central part of Ukraine). Milk is one of a person's most valuable foods. It enriches the human body with necessary substances: proteins, fats, and carbohydrates, which are in balanced proportions and easily assimilated. At the same time, it contains different enzymes, vitamins, and low-molecular microelements, which are necessary to ensure the regular exchange of substances. On the other hand, the choice of cow's milk is considered to be one of the largest sources of food, which is contaminated by toxic elements. The work aimed to determine the level of heavy metals in milk-raw materials received from cows from personal peasant farms in the Poltava district (Ukraine). We divided working samples into three groups; they had a territorial affiliation with the Dykanka, Reshetylivka, and Poltava communities (8 each). The samples were immediately cooled, transported to the laboratory, and stored at -20 °C for further analysis. The research was carried out using atomic and absorption spectrometry based on the Regional State Laboratory of Veterinary Medicine in the Poltava region. The Mann-Whitney test was used to compare the results. The P value below 0.05 was considered significant. So, in the milk of the group of the Dykanka territorial community, the contents of Cu were at 0.05 ± 0.01. In contrast, in the cows of the Poltava territorial community, this indicator was probably higher and made 0.08 ± 0.01 mg/kg (Р < 0.05). The concentration of copper in the milk of animals of the Reshetylivka territorial community did not exceed 0.06 ± 0.01 mg/kg, and it did not have a reliable difference from other groups. Content of Zn is probably lower in the group of the Dykanka territorial community, compared to other groups (2.6 ± 0.13), while in the group of Poltava territorial community, its concentration was 3.3 ± 0.25 (Р < 0.05), and in the group of the Reshetylivka territorial community – 3.45 ± 0.24 mg/kg (P < 0,01). In our studies, the range of heavy metals is presented as follows: Zn>Pb>Cu>As>Cd>Hg.На території Полтавського району (центральна частина України) визначено концентрацію важких металів (Pb, Cd, Cu, As, Zn, Hg) у коров’ячому молоці-сировині. Молоко належить до одного з найцінніших продуктів харчування людини. Воно збагачує організм людини необхідними речовинами: білками, жирами, вуглеводами, які містяться у збалансованих співвідношеннях і легко засвоюються. Водночас у ньому містяться різні ферменти, вітаміни, низькомолекулярні мікроелементи, які необхідні для забезпечення нормального обміну речовин. З іншого боку – незбиране коров’яче молоко вважається одним із найбільших джерел їжі, яке забруднене токсичними елементами. Метою роботи було визначити рівень важких металів у молоці-сировині, отриманого від корів із особистих селянських господарств Полтавського району, Україна. Робочі зразки ми розділили на 3 групи, які мали територіальну приналежність до Диканської, Решетилівської й Полтавської громад (по 8 проб з кожної). Зразки негайно охолоджували, транспортували в лабораторію та до подальшого аналізу зберігали за -20 °C.  Дослідження проведено методом атомно-абсорбційної спектрометрії на базі Регіональної державної лабораторії ветеринарної медицини в Полтавській області. Для попарного порівняння результатів використовували критерій Манна-Вітні. Значущими вважались відмінності між показниками у групах за P < 0,05. Так, у молоці групи Диканської територіальної громади вміст Cu був на рівні 0,05 ± 0,01, тимчасом як у корів Полтавської ТГ цей показник вірогідно вищий і становив 0,08 ± 0,01 мг/кг (Р < 0,05). Концентрація міді у молоці тварин Решетилівської ТГ не перевищувала 0,06 ± 0,01 мг/кг й вона не мала достовірної різниці між іншими групами. Вміст Zn вірогідно нижчий у групі Диканської ТГ, порівняно з іншими групами (2,6 ± 0,13), тимчасом як у групі Полтавської ТГ його концентрація була на рівні 3,3 ± 0,25 (Р < 0,05), а у групі РТГ – 3,45 ± 0,24 мг/кг (Р < 0,01). У наших дослідженнях ранжувальний ряд за рівнем важких металів поданий таким чином: Zn>Pb>Cu>As>Cd>Hg