laminin alpha 1 gene is essential for normal lens development in zebrafish

BACKGROUND: Laminins represent major components of basement membranes and play various roles in embryonic and adult tissues. The functional laminin molecule consists of three chains, alpha, beta and gamma, encoded by separate genes. There are twelve different laminin genes identified in mammals to date that are highly homologous in their sequence but different in their tissue distribution. The laminin alpha -1 gene was shown to have the most restricted expression pattern with strong expression in ocular structures, particularly in the developing and mature lens. RESULTS: We identified the zebrafish lama1 gene encoding a 3075-amino acid protein (lama1) that possesses strong identity with the human LAMA1. Zebrafish lama1 transcripts were detected at all stages of embryo development with the highest levels of expression in the developing lens, somites, nervous and urogenital systems. Translation of the lama1 gene was inhibited using two non-overlapping morpholino oligomers that were complementary to sequences surrounding translation initiation. Morphant embryos exhibited an arrest in lens development and abnormalities in the body axis length and curvature. CONCLUSION: These results underline the importance of the laminin alpha 1 for normal ocular development and provide a basis for further analysis of its developmental roles

The Computational Power of Optimization in Online Learning

We consider the fundamental problem of prediction with expert advice where the experts are "optimizable": there is a black-box optimization oracle that can be used to compute, in constant time, the leading expert in retrospect at any point in time. In this setting, we give a novel online algorithm that attains vanishing regret with respect to $N$ experts in total $\widetilde{O}(\sqrt{N})$ computation time. We also give a lower bound showing that this running time cannot be improved (up to log factors) in the oracle model, thereby exhibiting a quadratic speedup as compared to the standard, oracle-free setting where the required time for vanishing regret is $\widetilde{\Theta}(N)$. These results demonstrate an exponential gap between the power of optimization in online learning and its power in statistical learning: in the latter, an optimization oracle---i.e., an efficient empirical risk minimizer---allows to learn a finite hypothesis class of size $N$ in time $O(\log{N})$. We also study the implications of our results to learning in repeated zero-sum games, in a setting where the players have access to oracles that compute, in constant time, their best-response to any mixed strategy of their opponent. We show that the runtime required for approximating the minimax value of the game in this setting is $\widetilde{\Theta}(\sqrt{N})$, yielding again a quadratic improvement upon the oracle-free setting, where $\widetilde{\Theta}(N)$ is known to be tight

Using <i>Grammarly</i> to Enhance Students’ Academic Writing Skills

The paper aims to present the results of the experiment in applying the online writing assistant Grammarly.com to evaluate ESP students’ essay writing skills. One hundred master students’ papers were processed by the application to identify persisting errors at a master’s level. Quantitative and qualitative methods enabled the researchers to analyze the essays by setting five parameters: audience, formality, domain, tone, and intent. At the other end, the application broke down the outcome by five measurable factors: correctness, clarity, delivery, engagement, and style issues. The representative number of the essays fed into Grammarly.com provided a vivid and reliable picture of which lexis, grammar, structure, or style issues still need addressing. The most common mistakes detected by Grammarly.com were punctuation, wordy sentences, redundancy, and the abundance of personal pronouns in a formal style. They show that the gaps in students’ academic writing need a remedial course. Another objective of the research was to explore the potential of the online writing tool for students’ self-study. Grammarly.com cannot do work for students: it cannot think for them, neither can it write for them, but it can help learners identify the reoccurring writing problems, eliminate them, and monitor the progress. The application could be particularly useful for advanced students. The functionality of the Grammarly premium version allows for a choice of styles, type of addressee, tone of writing, and many other nuances, which could be beneficial not only for studies but in future professional life. Nonetheless, despite Grammarly’s advanced features, it only suggests a better variant, sometimes it errs, and in no way is it a substitute for a teacher

Subunit Mobility and the Chaperone Activity of Recombinant αB-Crystallin

The comparison of the chaperone-like activity of native and covalently cross-linked human αB-crystallins has confirmed the important role of the subunit mobility in the chaperoning mechanism. Our data clearly demonstrate that the chaperone-like activity of α-crystallin is not only a surface phenomenon as was suggested by some researchers

Electronic structure, charge transfer, and intrinsic luminescence of gadolinium oxide nanoparticles: Experiment and theory

The cubic (c) and monoclinic (m) polymorphs of Gd2O3 were studied using the combined analysis of several materials science techniques - X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. Density functional theory (DFT) based calculations for the samples under study were performed as well. The cubic phase of gadolinium oxide (c-Gd2O3) synthesized using a precipitation method exhibits spheroidal-like nanoclusters with well-defined edges assembled from primary nanoparticles with an average size of 50 nm, whereas the monoclinic phase of gadolinium oxide (m-Gd2O3) deposited using explosive pyrolysis has a denser structure compared with natural gadolinia. This phase also has a structure composed of three-dimensional complex agglomerates without clear-edged boundaries that are ~21 nm in size plus a cubic phase admixture of only 2 at. % composed of primary edge-boundary nanoparticles ~15 nm in size. These atomic features appear in the electronic structure as different defects ([Gd...O-OH] and [Gd...O-O]) and have dissimilar contributions to the charge-transfer processes among the appropriate electronic states with ambiguous contributions in the Gd 5p - O 2s core-like levels in the valence band structures. The origin of [Gd...O-OH] defects found by XPS was well-supported by PL analysis. The electronic and atomic structures of the synthesized gadolinias calculated using DFT were compared and discussed on the basis of the well-known joint OKT-van der Laan model, and good agreement was established.Comment: 27 pages, 10 figures, accepted in Appl. Surf. Sc

МОДЕЛИРОВАНИЕ УДАРНОГО КОНТАКТА ИНДЕНТОРА С НЕЖЕСТКИМИ СТАЛЬНЫМИ КОНСТРУКЦИЯМИ ПРИ ИЗМЕРЕНИИ ТВЕРДОСТИ

The problems of measuring hardness of constructions with insufficient rigidity by the dynamic indentation are discussed. The disadvantages of the existing dynamic hardness testers are described, the operation of which consists in impact indentation and determination of the hardness, depending on the restitution coefficient. Finite-element models of the contact of the indenter and the pipes samples with various wall thicknesses and diameters and cantilevered plates of various thicknesses are developed. Indentation diagrams for the investigated samples of pipes and plates in the coordinate plane of force-displacement are obtained. The results of the simulation have good convergence with the experimental data. With the help of the finite element models the separation of local penetration and deflection of construction is made. It is shown the influence of steel construction deflection on the process of indenter impression into the material tested and the change of indentation parameters as restitution coefficient, contact force, penetration depth and time of the active part of the impact. The limits of possible application of dynamic hardness testers have been determined. The ways of the increasing of the hardness measurement accuracy on the base of the data obtained during impact interaction are shown. It is established that the use of dependences between hardness and the time of the active stage of impact, as well as the ratio of the contact force to the depth of penetration at the loading stage, makes it possible to evaluate the hardness for pipes with the wall thickness exceeding 5 mm and cantilevered plates at the distance from the fixed support up to 100 mm. Рассматриваются вопросы измерения твердости конструкций недостаточной жесткости методом ударного вдавливания индентора. Описываются недостатки существующих динамических твердомеров, принцип действия которых заключается в нанесении удара по испытуемому образцу и регистрации коэффициента восстановления скорости, зависящего от твердости. Построены конечно-элементные модели ударного взаимодействия индентора с образцами труб с различной толщиной стенки и диаметром, а также консольно закрепленных пластин разной толщины. Получены диаграммы вдавливания индентора в исследуемые образцы труб и пластин в координатах контактное усилие – перемещение. Показана достаточно хорошая сходимость между результатами моделирования и экспериментальными данными, полученными на твердомере, позволяющем регистрировать кривую нагружения в процессе ударного взаимодействия. С помощью построенных конечно-элементных моделей выделен вклад локальной деформации и прогиба в общий отклик конструкции при индентировании. Установлено влияние прогиба конструкций на процесс внедрения индентора в материал, а также на такие параметры индентирования, как коэффициент восстановления скорости, контактное усилие, перемещение и время активного этапа удара. Определены границы допустимого использования твердомеров ударного действия. Показаны пути повышения точности измерения твердости на основе данных, получаемых на этапе внедрения индентора. Установлено, что использование градуировочных зависимостей между твердостью и временем активного этапа удара, а также отношением контактного усилия к глубине внедрения на этапе нагружения позволяет провести оценку твердости для труб с толщиной стенки свыше 5 мм и консольно закрепленных пластин на расстоянии от места закрепления вплоть до 100 мм.

Mathematical justification balance of masticatory muscles on the results of electromyographic studies

The main function of dentogingival protective capsules in contact sports is: good protection of teeth, soft tissues, temporomandibular joint and reduction of the likelihood of brain concussion; besides, they should provide optimal fixation in the oral cavity and maximum comfort of the athlete. However, today more and more researchers are studying the improvement of their quality due to additional opportunities. The aim of the study was to develop and investigate the technology of balancing the optimal state of chewing muscles by means of an individual relaxation device for determining the height of the lower facial part. For the study, we conducted electromyographic studies of 10 athletes who were engaged in boxing at the age of 17 to 22 years. Each of them was made a relaxation device in the form of an individual spoon on the upper and lower jaws, connected together by a spring mechanism (an application for an invention was filed). With the help of chewing movements of the jaw, the patient led the relaxation device for 5,10 and 15 minutes. The main parameters of the study are the activity time [ms], the filling time [Hz] and the activity period (the number of amplitudes], the maximum and minimum values (pV). The results of the research showed that the period of influence of the relaxation device on muscle tone, at which their maximum relaxation in the set of parameters is observed, can be considered as the most favorable (optimal) for the manufacture of a tooth-drop

Clinical case of de novo anaplastic ganglioglioma and current status of the problem

The authors report a rare case of de novo malignant ganglioglioma (WHO grade III) in a 26-year old female. The patient has complained of periodic feeling fear, anxiety, episodes of impaired consciousness with extremity muscle cramps sometimes followed by urination, as well as flashes before eyes. Computed tomography perfusion and magnetic resonance spectroscopy were carried out for differential diagnosis between different types of tumors. Stereotactic biopsy was performed for histological examination. High surgical risk became a contraindication to gross total resection of the tumor. The patient has received radiation therapy (Trilogy linear accelerator) in a total dose of 60 Gy. The tumor shrank significantly. In 7 months, monitoring MRT did not detect further growth of the tumor. The authors have analyzed the case and reviewed the existing literature data regarding gangliogliomas. Taking into account low prevalence of these tumors (0.4-1% of all brain tumors), especially of their malignant forms (3-10% of gangliogliomas), lack of sufficient data regarding prognostic factors, life expectancy, time of recurrence, lack of accurate indications for different methods of treatment (surgery, radiation, chemotherapy), these tumors still need further research that should also involve supplementary neuroimaging techniques and stereotactic biopsy

ОСОБЕННОСТИ ПОРАЖЕНИЯ СИГНАЛЬНЫХ ЛИМФАТИЧЕСКИХ УЗЛОВ ПРИ ПЕРВИЧНОЙ МЕЛАНОМЕ КОЖИ

Introduction. Each tenth tumor of skin is melanoma. Presence of tumor cells in sentinel lymph node influenced the medical tactics.The objective of the research was to study the metastasis of skin melanoma into the clinically negative regional lymph nodes.Material and methods. Histological, immunohistochemical, cytological and immunocytochemical methods were used to study biopsies of regional lymph nodes in 60 patients with skin melanoma.Results. 5 % of patients were diagnosed with melanoma in situ, 15 % – Т1, 28.3 % – Т2, 23.3 % – Т3, 28.3 % – Т4. At outflow of the lymph through 1 collector, the metastases in sentinel lymph node (SLN) was defined in 51 %, through 2 collectors – in 81.8 % of cases. Tumor cells damaged single lymph node in 35.3 % of cases, two and more lymph nodes in 64.7 % of cases. Metastases in SLN with formation of secondary tumor at the T1 melanoma were observed at 11.1 %, T2 – 5.9 %, T3 – 21.4 %, T4 – 47.1 % of studies. Clusters of cells or isolated cells of melanoma in SLN at Т1 were noted in 22.2 %, at Т2 – in 41.2 %, at Т3 – in 42.9 %, at Т4 – in 35.3 % of cases. At outflow of lymph through 1 collector, metastasises of melanoma in non-sentinel lymph nodes (NSLN) were revealed in 24 %, through 2 collectors – in 44.4 % of cases. Secondary changes of NSLN were noted in 16.7 % of cases of defeat of single SLN, in 31.8 % of cases of defeat of two and more SLN. Metastases of melanoma were revealed in 69.2 % of cases of formation of secondary tumor and in 4.8 % of cases of presence of clusters in SLN in removed NSLN.Conclusion. At increase of Тmelanoma of the skin, the quantity of sentinel lymph nodes with reactive changes decreased, and their number with metastases increased. Metastatic defeat of sentinel lymph nodes at outflow of lymph through 2 lymph collectors in two and more SLN and NSLN exceeded the defeat of SLN at outflow of lymph through 1 lymph collector in single lymph nodes. The use of immunocytochemical method of research allowed to expand pathomorphological verification of metastatic defeat of sentinel lymph nodes by 66.7%.Введение. Каждая 10-я опухоль кожи – меланома, на план лечения которой влияет наличие опухолевых клеток в сигнальном лимфоузле.Цель исследования – изучение метастазирования меланомы кожи в клинически негативные региональные лимфатические узлы.Материал и методы. Гистологическим, иммуногистохимическим, цитологическим и иммуноцитохимическим методами исследованы биоптаты региональных лимфатических узлов 60 пациентов с меланомой кожи.Результаты. У 5 % пациентов диагностирована меланома в стадии in situ, у 15 % – Т1, у 28,3 % – Т2, у 23,3 % – Т3, у 28,3 % – Т4. При оттоке лимфы через 1 лимфоколлектор метастазы в сигнальном лимфоузле (СЛУ) определили в 51 %, через 2 лимфоколлектора – в 81,8 % случаев. В 35,3 % случаев опухолевые клетки поражали единичный лимфоузел, в 64,7 % – 2 и более лимфоузла. Метастазы в СЛУ с формированием вторичной опухоли при меланоме Т1 наблюдали в 11,1 %, Т2 – в 5,9 %, Т3 – в 21,4 %, Т4 – в 47,1 % исследований. Скопления клеток по типу кластера или разрозненные клетки меланомы в СЛУ при Т1 отмечены в 22,2 %, при Т2 – в 41,2 %, при Т3 – в 42,9 %, при Т4 – в 35,3 % случаев. При оттоке лимфы через 1 коллектор метастазы меланомы в несигнальных лимфоузлах (НСЛУ) выявлены в 24 %, через 2 коллектора – в 44,4 % случаев. Вторичные изменения НСЛУ отметили в 16,7 % случаев поражения единичного СЛУ, в 31,8 % наблюдений – поражения 2 и более СЛУ. В 69,2 % случаев формирования вторичной опухоли и в 4,8 % наличия кластеров в СЛУ в удаленных НСЛУ обнаружены метастазы меланомы.Выводы. При нарастании Т меланомы кожи уменьшалось число сигнальных лимфатических узлов с реактивными изменениями, и возрастала их численность с метастазами. Метастатическое поражение сигнальных лимфатических узлов при оттоке лимфы через 2 лимфоколлектора в 2 и более СЛУ и НСЛУ превышало поражение СЛУ при оттоке лимфы через 1 лимфоколлектор в единичные лимфоузлы. Использование иммуноцитохимического метода исследования позволило на 66,7 % расширить патоморфологическую верификацию метастатического поражения сигнальных лимфатических узлов