Structure Research Articles

The Prenatal Rating of Efficacy in Preparation to Breastfeed Scale (PREP to BF): A Turkish validity and reliability study

Objective: Breastfeeding self-efficacy is an easy-to-evaluate and easy-to-change variable. The prenatal period is an ideal time period for women to gain breastfeeding self-efficacy. Valid and reliable measurement tools are needed to assess breastfeeding self-efficacy. The purpose of this study is to examine psychometric analyzes of Turkish form of the Prenatal Rating of Efficacy in Preparation to Breastfeed Scale. Methods: This is a methodological study. The study was conducted obstetrics and outpatient clinics in the a state hospitals at the Turkey. The study was administered to 407 pregnant women. The relevant data were collected through the use of a Personal Information Form, The Prenatal Rating Of Efficacy in Preparation To Breastfeed Scale. Internal consistency coefficient, split-half reliability and item analysis to assess the reliability of the scale, factor analysis was performed to evaluate the validity of the scale. Results: Cronbach Alpha coefficient of scale was 0.96. A 5-factor structure with eigenvalues above 1 that explained 71.267% of the variance emerged. The model fitted the observed data in terms of these fit index values, and that the Turkish version of the scale demonstrated an acceptable level of fit. Conclusion: The scale can be employed by healthcare professionals to assess prenatal breastfeeding self-efficacy. It can contribute data for the structuring of the content of training and consultancy programs intending to improve breastfeeding self-efficacy.

Wavefront control technology for ICF facility in China

In the high-power laser system for inertial confinement fusion, wavefront control is one of the key technologies for the laser system to ensure it operates safely and reaches the beam quality criteria. In this article, the development of the wavefront control technology from its first being putting forward for the ICF laser system to its application in the latest ICF laser system in China was introduced. During the development of the ICF facilities, the wavefront control methods are varying to satisfy the varied demands promoted by these facilities. Based on different facilities, the methods and the application results are illustrated, including the climbing wavefront method for far-field spot optimization, the full-facility wavefront control method based on the data fusion acquired from two wavefront sensors, and the full-system wavefront control method with bi-deformed mirrors in the rotation chamber laser structure.

A MODEL FOR OPTIMIZING THE STRUCTURE OF TEACHING TECHNIQUES FOR DISTANCE LEARNING IN THE RUSSIAN HIGHER EDUCATION SYSTEM

Purpose of the study: This study aims to develop a methodical approach to optimize the structure of teaching techniques and approaches to distance education, as exemplified by Russian universities, to enhance students’ professional competencies. Methodology: A pedagogical experiment was conducted with the participation of 746 second- to fourth-year students majoring in engineering at the Ural Federal University in Russia. The coefficients for the relative importance of professional competencies were obtained through expert assessment. The number of experts was 40 faculty members with teaching experience of more than five years. Main findings: The pedagogical experiment revealed the regularities of the influence of the forms of distance learning on the formation of students’ professional competency levels. The values of students’ developmental competency levels have been determined. Non-linear regression models have been developed based on the values of the integral level of professional competencies and the percentage of distance learning forms in the number of instructional hours. Applications of this study: The proposed methodological approach will be useful for university professors and teachers in identifying the most effective forms of distance learning and in differentiating teaching methods not only in the context of the general pandemic but also in the natural conditions of the educational process. Novelty/originality of this study: The originality of this study is in the application of empirical methods to obtain a quantitative assessment of certain distance learning methods use effectiveness and their trend towards the professional competence formation level. This enables us to take into account students' characteristics in the process of distance learning and to correct the academic discipline teaching technologies in time.

Аналіз ризосферного мікробіому цукрової кукурудзи за впливу хімічних і біологічних протруйників

У статті представлено результати впливу хімічних і біологічних протруйників на кількісний склад мікробіому ризосфери цукрової кукурудзи протягом її вегетації. Показано, що за використання хімічних препаратів у ризосфері рослин на порядок знижується кількість амоніфікаторів та мікроскопічних грибів у першій половині вегетаційного періоду культури. Вплив ксенобіотиків на вміст актиноміцетів, олігонітрофілів та педоторофів є менш токсичним. У порівнянні з контрольним варіантом вміст даних мікроорганізмів знижувався на 50-75 %, при цьому змін зазнає не лише кількісний, а й якісний склад ризосферної мікрофлори. У той же час досліджувані пестициди не впливали на вміст актиноміцетів і оліготрофів. По мірі розвитку рослин негативний вплив хімічних протруйників на мікрофлору ґрунту поступово нівелювався. Відбувалося відновлення складу ризосферної мікробіоти у кожній умовній функціональній групі мікроорганізмів і до завершення вегетації кукурудзи мікробний ценоз повертався до свого первинного кількісного і якісного складу. Застосування мікробіологічних засобів захисту не призводило до змін чисельності чи дисбалансу у складі ґрунтової мікробіоти. Її кількісний та якісний склад відповідав контрольному варіанту.

COVID-19’UN TOPLUMDA YAYILIMINI ÖNLEMEYE YÖNELİK İLAÇ DIŞI HALK SAĞLIĞI ÖNLEMLERİ

COVID-19'u tedavi etmek veya önlemek için etkili spesifik ilaç veya aşı olmadığı için halk sağlığı önlemleri salgına yanıt vermenin tek yoludur. Hastalığın yayılmasını kontrol etmek ve kontrol önlemlerinin sürekli uygulanmasını sağlamak için etkili şekilde sürveyansın yapılması kritik önem taşımaktadır. Halk sağlığı önlemlerinden özellikle el ve solunum hijyeni, sosyal mesafenin uygulanması, izolasyon, karantina; solunum hastalıklarının yavaş bulaşması ve sağlık kuruluşlarının bu hastalıklarla daha iyi başa çıkabilmesi için önemlidir. Sosyal mesafe, özellikle toplum yayılımının gerçekleştiği, ancak vakalar arasındaki bağlantıların belirsiz olduğu durumlarda yararlıdır. Mesafe uzadıkça bulaşın azaldığı, maske kullanımının hem sağlık çalışanları için hem de toplumda etkene maruz kalan insanlar için koruyucu olduğu gösterilmiştir. Yapılan çalışmalarda ikinci bir dalgadan korunmak için toplum bağışıklığının henüz yetersiz olması nedeniyle alınan halk sağlığı önlemlerinin devam etmesi gerektiğinin göstergesidir. Sürecin uzaması bireylerde önlemlere uyumda azalmaya ve uyum yorgunluğuna da neden olabilir. Salgının kontrol alınmasıyla politika yapıcılar sağlık sistemi kapasitesinin aşılmadan, halk sağlığı önlemleri ile kontrollü sosyal yaşamı benimsemektedir. Sonuç olarak; COVID-19 salgını kontrolü için en önemli basamak olan halk sağlığı önlemlerin sürekliliği toplumun sosyokültürel yapısı göz önüne alınarak sağlanmalıdır. Önlemlerin uygulanabilir olması, bireysel uyum için ekonomik altyapının sağlanması, salgın başından itibaren her ülkenin sürveyans kapasitesini önemli düzeyde artırması gereklidir.

Discriminative subspace matrix factorization for multiview data clustering

In a real-world scenario, an object is easily considered as features combined by multiple views in reality. Thus, multiview features can be encoded into a unified and discriminative framework to achieve satisfactory clustering performance. An increasing number of algorithms have been proposed for multiview data clustering. However, existing multiview methods have several drawbacks. First, most multiview algorithms focus only on origin data in high dimension directly without the intrinsic structure in the relative low-dimensional subspace. Spectral and manifold-based methods ignore pseudo-information that can be extracted from the optimization process. Thus, we design an unsupervised nonnegative matrix factorization (NMF)-based method called discriminative multiview subspace matrix factorization (DMSMF) for clustering. We provide the following contributions. (1) We extend linear discriminant analysis and NMF to a multiview version and connect them to a unified framework to learn in the discriminant subspace. (2) We propose a multiview manifold regularization term and discriminant multiview manifold regularization term that instruct the regularization term to discriminate different classes and obtain the geometry st ructure from the low-dimensional subspace. (3) We design an effective optimization algorithm with proven convergence to obtain an optimal solution procedure for the complex model. Adequate experiments are conducted on multiple benchmark datasets. Finally, we demonstrate that our model is superior to other comparable multiview data clustering algorithms.

Pharmacological agents and natural compounds: available treatments for osteoporosis.

Osteoporosis, a systemic skeletal disease characterized by a decrease in bone mass and deterioration of bone structure leading to an increased risk of fragility fractures, represents one of the major health problems worldwide. Currently, there are numerous pharmacological products used for the treatment of osteoporosis. Anti-resorptive drugs include bisphosphonates, hormone therapy, selective estrogen-receptor modulators, calcitonin, denosumab, calcium and vitamin D supplementation. Anabolic drugs such as teriparatide, strontium ranelate, romosozumab have recently become available based on advanced clinical trials. In recent years, combination therapy of anabolic and anti-resorptive agents is expected to be ideal anti-osteoporosis option. The adverse side effects caused by the long-term administration of pharmacological drugs have prompted researchers to study natural therapeutic compounds to find an alternative and effective way for osteoporosis treatment. Natural compounds including phytoestrogens with estrogenic effects (e.g. genistein, daidzein, icariin, dioscin, Ginkgo biloba), antioxidant and anti-inflammatory agents (e.g. acteoside, curcumin, resveratrol, Camellia sinensis), treatments that exert their effects by multiple actions (e.g. kinsenoside, berberine, Olea europaea, Prunus domestica, Allium cepa) could provide a safer alternative to primary pharmacological strategies. In this review, both pharmacological agents and natural compounds as available treatments for osteoporosis are characterized. In addition, possible mechanisms of action of all aforementioned treatments associated with bone remodelling, osteoclastogenesis, osteoblastogenesis, bone cell activity, death, and oxidative stress are presented. Nevertheless, more high-quality clinical studies with natural compounds are needed to provide greater evidence of the beneficial and safer antiosteoporotic application for the candidate.

Macrofauna edáfica em cultivo orgânico de cana-de-açúcar no norte do estado do Paraná, Brasil

Os organismos do solo desempenham papel predominante na formação e manutenção da estrutura do solo, e suas atividades afetam os processos físicos, químicos e biológicos do ecossistema edáfico. O objetivo deste trabalho foi realizar um levantamento da macrofauna edáfica em um sistema de cultivo orgânico de cana-de-açúcar. Foram realizadas amostragens de solo no verão e inverno, nos anos de 2014 e 2015utilizando-se monólito para a coleta, e separando o solo em três camadas nas profundidades de 0-10, 10-20 e 20-30 cm. Em laboratório as amostras foram triadas e os invertebrados separados em Filos, contados e identificados. Os valores de abundância foram submetidos ao teste de médias Fisher LSD (p< 0,05) e feita também a Análise de Componentes Principais (ACP). Foram encontrados 5.760 indivíduos m-², concentrados na camada de 0-10 cm da superfície do solo, e no verão de 2014 ocorreu a maior diversidade populacional da macrofauna edáfica. Predominaram os grupos Formicidae, Chilopoda, Isopoda e Oligochaeta e, neste último, a espécie peregrina Pontoscolex corethrurus, cuja ocorrência sugere perturbações antrópicas.

Participation of the intestinal microbiota in the mechanism of beneficial effect of treatment with synbiotic Syngut on experimental colitis under stress conditions.

Gut-brain axis plays a central role in the regulation of stress related diseases such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). It is increasingly recognized that stress modulates gut microbiota community structure and activity and represents an important causal factor in dysbiosis. This study was designed to determine the effect of daily treatment with synbiotic (Syngut) containing inulin, Lactobacillus acidophilus, Bifidobacterium lactis W51, Lactobacillus plantarum W21 and Lactococcus lactis applied i.g. at a dose of 50 mg/kg i.g. on the colonic damage and colonic mucosal blood flow in rats with experimentally induced TNBS-colitis that were additionally exposed or not to acute stress (episodes of cold restraint stress every other day before colitis induction). Control rats received daily treatment with vehicle (saline, i.g.) or mesalazine (50 mg/kg-d i.g.), the standard drug recommended in therapy of IBD. At the termination of TNBS colitis, the histologic evaluation of colonic mucosa, mucosal malonyldialdehyde (MDA) level and plasma concentrations of proinflammatory cytokines (TNF-α, IL-1β) and adipokine adiponectin were assessed. the samples of colonic mucosa not involving colonic lesions and surrounding the flared mucosa were excised for the determination of mRNA expression for proinflammatory biomarkers TNF-α, IL-1β, IL-10 and COX-2 as well as antioxidazing factors SOD-1 and SOD-2. Finally, the gut microbial profiles were analyzed by 16S rRNA sequencing at phylum, family and genus level. Episodes of cold stress significantly aggravated the course of TNBS colitis, and significantly increased the release of proinflammatory cytokines as well as the significant increase in the MDA concentration has been observed as compared with non-stressed TNBS rats. These changes were followed by the significant fall in the CBF and plasma adiponectin levels and by the overexpression of mRNA of proinflammatory biomarkers. Synbiotic treatment with Syngut significantly reduced the area of colonic lesions observed macroscopically and microscopically in rats with TNBS colitis with or without exposure to cold stress, significantly increased the CBF, normalized plasma adiponectin levels and significantly attenuated the release and colonic expression of proinflammatory cytokines and biomarkers. the analysis of the gut microbiota showed a significant reduction of microbial diversity (Shannon index) in rats with TNBS colitis with or without exposure to stress. The therapy with Syngut failed to significantly affect the alpha diversity. At the phylum level, the significant rise in Proteobacteria has been observed in stressed rats with TNBS colitis and this effects was attenuated by treatment with Syngut. At family level, TNBS colitis alone or in combination with stress led to a significant decrease of SCFA producing bacterial taxa such as Ruminococaceae and Lachnospiraceae and Syngut counteracted this effect. We conclude that: 1) cold stress exacerbates the gastrointestinal inflammation in experimental colitis; 2) the synbiotic therapy with Syngut ameliorates the gut inflammation in rats with TNBS colitis combined with cold stress; 3) the beneficial effect of Syngut is accompanied by increase of anti-inflammatory taxa such as Ruminococaceae and Lachnospiraceae, and 4) the modulation of gut microbiota with Syngut alleviates stress-related intestinal inflammation suggesting a potential usefulness of synbiotic therapy in intestinal disorders accompanied by stress in patients with IBD.

Distribuição espacial e estrutura populacional de Pilosocereus pachycladus F. Ritter subsp. pernambucoensis (F. Ritter) Zappi e Cereus jamacaru DC. subsp. jamacaru

A família Cactaceae apresenta mais de 1.500 espécies no mundo, ocorrendo espécies endêmicas em todo o território nacional. Em populações naturais, tais elementos sofrem fortes pressões antrópicas, o que aumenta consideravelmente o seu risco de extinção. O objetivo do trabalho foi realizar um estudo sobre a distribuição espacial e estrutura populacional de Pilosocereus pachycladus F. Ritter subsp. pernambucoensis (F. Ritter) Zappi e Cereus jamacaru DC. subsp. jamacaru em duas áreas de Caatinga do Agreste do estado da Paraíba, Brasil. Os ambientes de estudo estão localizados no Instituto Nacional do Semiárido (INSA), Campina Grande-PB, e no Sítio Umburana, Bananeiras-PB. Foram alocadas 10 parcelas amostrais de 400 m² em cada ambiente de estudo, e todos os indivíduos de P. pachycladus subsp. pernambucoensis e C. jamacaru subsp. jamacaru foram contabilizados. A distribuição espacial das espécies, não apresentaram tendência ao agrupamento nas populações localizadas no INSA. Nas populações do Sítio Umburana, a tendência é ao agrupamento. De acordo com índice de agrupamento de Payandeh (Pi) a densidade populacional e absoluta nas populações do Sítio Umburana é maior, se comparado às populações do INSA. Para os padrões espaciais, nas populações de Cactaceae do Sítio Umburana, os indivíduos de ambas as espécies apresentam distribuição agrupada e nas populações do INSA apresentaram a tendência ao não agrupamento. Fatores como distúrbios naturais ou antrópicos, condições ambientais e disponibilidade de recursos, influenciaram a estrutura populacional de P. pachycladus e C. jamacaru.

Особливості франчайзингової експансії на український туристичний ринок

Мета дослідження - визначити відмінності впровадження моделі франчайзингу туристичними операторами на європейському та українському ринках.
 Дизайн/Метод/План дослідження. Теоретичний підхід, що ґрунтується на узагальненні, системному й порівняльному аналізі. Застосовані контент-аналіз, статистичний, графічний і табличний методи. 
 Результати дослідження. Охарактеризовано моделі ділового франчайзингу найбільших багатопрофільних туристичних операторів масового туризму в Україні. Визначено загальні умови здійснення туристичної діяльності на принципах ділового франчайзингу для туристичних агенцій. З’ясовано відмінності моделей ділового франчайзингу на європейському й українському ринках. Франчайзинг визначено механізмом мультиплікації бізнесу й кооперації можливостей, спрямованих на активне просування туристичного продукту на цільовий на ринок.
 Практичне значення дослідження. Практичне значення отриманих результатів дослідження полягає у можливому їх застосуванні туристичними агенціями при прийнятті рішення про приєднання до франчайзингової мережі й туроператорами при вирішенні питань диверсифікації прогнозованих ризиків бізнесу.
 Оригінальність / цінність / наукова новизна дослідження. Новизною проведеного дослідження є уточнення умов провадження туристичної діяльності на засадах франчайзингу в країнах Європи й, зокрема, в Україні, виділення відмінних рис моделі європейського ділового франчайзингу, які полягають у чітко визначеній вертикально інтегрованій структурі управління, сильному національному маркетинговому менеджменті, корпоративній підтримці ведення бізнесу, довгостроковості франчайзингових угод, результативній системі франчайзі.
 Перспективи подальших досліджень / обмеження дослідження. Внаслідок економічної кризи в туристичному бізнесі перспективним напрямом подальших досліджень з цієї проблематики є пошук шляхів стабілізації діяльності мережевого бізнесу в туризмі. Викликає інтерес зміна фінансового стану туристичних агентств після отримання або припинення статусу франчайзі.
 Тип статті - теоретичний.

Estudo de viabilidade para a reutilização de plataformas offshore fixa como substrutura de torres eólica

Com o objetivo de dar um outro uso às plataformas offshore fixa com o tempo de vida útil vencidas, principalmente aquelas situadas em campos com condições ambientais favoráveis para instalação de turbinas eólicas offshore, o presente trabalho de pesquisa ressalta a importância de avaliar a possibilidade de reutilização de uma plataforma (jaqueta) submetida ao carregamento de uma torres de 10 MW, considerando sobre tudo as novas condições de operação. Para isso se tem em conta as análises dos elementos que conformam a estrutura (jaqueta) de modos a atinar as suas respetivas razões de tensões. Considerou-se o carregamento da torre eólica de maneira pontualmente distribuído sobre os 4 nós no topo das pernas principais da jaqueta. A estrutura investigada apresenta uma jaqueta de 16,85 m de altura, com a área da mesa inferior de 9,95 m x 9,95 m e 6,75 m x 6,75 m na mesa superior. O sistema estrutural foi desenvolvido com base à utilização do software OrcaFlex V10.3, que permite analisar as razões de tensões (“Unity Check”) incluído os efeitos de segunda ordem por meio da utilização do Método dos Elementos Finitos (MEF). Desta forma, os resultados obtidos ao longo das análises para avaliar o comportamento estrutural apontam para o fato de que a jaqueta investigada não atende aos critérios de projeto para dar suporte a torres eólicas de 10 MW.

Super Tau-Charm Facility of China

The tau-charm region is one of the most important energy regions in the research of particle physics due to its unique properties, rich frontier topics and great potential for scientific discovery. In order to maintain our country's pioneering position in the tau-charm research field, we propose to build a new generation electron-positron collider—the Super Tau-Charm Facility (STCF), based on the Hefei National Synchrotron Radiation Laboratory, the State Key Laboratory of Particle Detection and Electronics, and other research platforms. The STCF would have a luminosity greater than 0.5×1035 cm-2 s-1, and a center-of-mass energy region of 2 to 7 GeV. Its performance is expected to be significantly better than the currently running BEPCII, and will provide a key platform for exploring the asymmetry of matter-antimatter (charge parity violation), in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions, as well as the quest for exotic particles and physics beyond the standard model. The construction of STCF poses a great challenge to the existing accelerator and detector technologies in China, but is very important scientifically and strategically not only for fundamental scientific research but also for the development of new technology and the cultivation of comprehensive expertise.

Circular sliding solution of mining stability and failure depth of floor layered structure on coal face

Circular sliding solution of mining stability and failure depth of floor layered structure on coal face

Mapeamento de fatores complexos na indústria da construção civil: taxonomia e proposição de diretrizes para mitigar o impacto na saúde, segurança e bem-estar dos trabalhadores

The structure of civil construction projects is characterized as complex due to the involvement of several activities that are separate and diversified for a certain period of time, therefore, it is necessary to create a temporary multi-organizational structure for their management. In view of this complex system of simultaneous multitasking, the need to protect employees began to be observed, taking into account the social point of view, in order to obtain improvements and avoid the loss of human resources. In this context, there was an essential gap to be answered, since the identification of these complex factors leads to the possibility of proposing a strategy in order to mitigate their influence on the health, well-being and safety of workers. The purpose of this dissertation is to map the factors that influence complexity in the Civil Construction sector, highlighting the most relevant factors for the health, safety and well-being of workers and propose a system to address the complexity of this system. In the methodological aspect, a survey was carried out in the literature on the factors responsible for the complexity in civil construction. In their possession, it was identified that there was convergence between the factors, with that a taxonomy was made in order to raise the most relevant for the studied area. Through taxonomy, 9 factors were found that were most relevant to the area of civil construction, which were part of a questionnaire in order to format an exploratory survey, which was sent to a group of specialists in the areas of engineering, health and safety of work. After the result of the survey with specialists, it was sought to verify which factors are most relevant for those involved to propose actions to mitigate the influence of these factors in the lives of workers. The research can be classified as applied, exploratory, supported by qualitative and quantitative analysis to describe the situations identified through the result of interviews. As a result, the factors responsible for the complexity in civil construction were found, the most relevant ones found through a taxonomy, the most important ones were verified according to the point of view of specialists in relation to the health, safety and well-being of the worker and proposed guidelines for the mitigation of some complex factors in civil construction projects. Therefore, it is expected to awaken the interest of managers in the Civil Construction Industry to the complexity factors raised as well as to show the importance of developing an action plan to be implemented in order to mitigate unsafe situations.

Sınıf Öğretmeni Adaylarının Bilim ve Sanat Merkezi’ne Yönelik Analojileri

Analoji, kavram ve ilkelerin benzer olan özellikleri arasında yapılan bir haritalama biçimidir. Analoji, yeni bir bilginin öğrenilmesinde, anlaşılmasında kullanılan bir çeşit betimleme türüdür. Bireylerin iyi düzeyde öğrenilmiş ve uzun süreli bellekte yer alan bilgilerinin yeni öğrenilecek olanlar için kullanılmasında önemli bir rolü vardır. Bu araştırmanın amacı, sınıf öğretmeni adaylarının Bilim ve Sanat Merkezi’ne yönelik analojilerini belirlemek ve bu kuruma yönelik algılarını ortaya çıkarmaktır. Araştırmanın örneklemini, 2019–2020 Eğitim-Öğretim yılında Çanakkale Onsekiz Mart Üniversitesi Temel Eğitim Bölümü Sınıf Eğitimi Anabilim dalına devam eden 112 öğretmen adayı oluşturmaktadır. Araştırmada nitel araştırma yöntemi kullanılmıştır. Elde edilen veriler, içerik analizi yapılarak çözümlenmiştir. Araştırmanın verileri, öğretmen adaylarının Bilim ve Sanat Merkezi’ne (BİLSEM) yönelik ne tür analojiler kullandıklarını ortaya çıkarmak için araştırmacılar tarafından hazırlanan 10 sorudan oluşan form kullanılarak toplanmıştır. Araştırmada öğretmen adaylarının oluşturduğu analojilerin yapısal, fonksiyonel, hem yapısal hem de fonksiyonel olduğu, çok azının resimsel analojiler ve sözel-resimsel analojiler sınıflandırması altında yer aldığı görülmüştür. Adayların geliştirdikleri analojilerin sınırlılık ve gerekçelerini belirtmemeleri ve hedef kavramı açıklamak için birden fazla kaynak kullanmamaları, Bilim ve Sanat Merkezi kurumunun genel yapısı ile ilgili çok yönlü olarak bilgi sahibi olmadıklarını düşündürmektedir. Sınıf öğretmeni adaylarının büyük çoğunluğun Bilim ve Sanat Merkezleri hakkında olumlu benzetmeler yapmaları, bu kurumların işlevini yerine getirmeleri bakımından önemlidir.

Caracterización de cristales líquidos con Miconazol en sistemas bifásicos por microscopía de polarización

Introducción: las emulsiones son un tipo de preparado farmacéutico muy utilizado en aplicación tópica consistentes en sistemas bifásicos de aceite-agua o agua-aceite, donde el principio activo deseado se incorpora en una de las fases dependiendo de su solubilidad. Diversos estudios demuestran que la estabilidad es mayor en emulsiones con estructuras líquido-cristalinas. El principio activo liposoluble Miconazol, que actúa como antimicótico, se solubiliza en la fase oleosa de la emulsión y en la fracción de la cadena hidrocarbonada de los cristales líquidos. Método: se utilizaron técnicas microscópicas para analizar las características de una emulsión convencional y de otra con cristales líquidos, a las que se les incorporó el principio activo Miconazol. Se determinaron las dimensiones de las gotas de la fase interna y mediante microscopía de polarización se caracterizaron los cristales líquidos. Resultados: el análisis de las imágenes microscópicas permitió determinar que en las formulaciones con cristales líquidos con y sin Miconazol, aproximadamente el 80 % de las gotas tienen dimensiones en el intervalo 0,5 µm - 1 µm. Las observaciones microscópicas con luz polarizada nos permitieron determinar que los cristales líquidos tienen birrefringencia con la formación de cruces de extinción uniáxicas negativas, las cuales son características de las fases liotrópicas laminares con texturas cónicas focales. Conclusiones: los resultados muestran que el agregado de Miconazol, no interfiere con la formación de la estructura de los cristales líquidos, por lo que estas dependen de los componentes de la formulación y de la técnica de preparación.

The Structure of the Literary Problem in the Formation of the Local Text Substrate

The Structure of the Literary Problem in the Formation of the Local Text Substrate

Cover Feature: Incorporation of Boron into Uranium Metallacycles: Synthesis, Structure, and Reactivity of Boron‐Containing Uranacycles Derived from Bis(alkynyl)boranes (Chem. Eur. J. 60/2020)

Cover Feature: Incorporation of Boron into Uranium Metallacycles: Synthesis, Structure, and Reactivity of Boron‐Containing Uranacycles Derived from Bis(alkynyl)boranes (Chem. Eur. J. 60/2020)

Lateral support structure for 600 mm primary mirror of laser communication

The main function of the laser communication large-caliber ground optical transceiver is to establish a communication link with the satellite to realize data transmission between the satellite and the ground station. The 600 mm microcrystalline primary mirror of one laser communication station is heavy, and its working angle changes constantly. In order to decrease the mirror surface error, the support system not only has a 9-pose axial support structure but also simultaneously balances the radial component of gravity of the primary mirror at its working angle by using a radial support structure. Flexible lateral support structures have large size and stress, so it is not suit for the mirror that works in a wide range of rotation. The paper researches the lateral support structure with a mercury band and central shaft, and analyses the impact of mercury band parameters on the surface error. The designed lateral structure has small size and improves the surface quality of the mirror. The measured values of PV and RMS are smaller than λ/5 and λ/37, respectively. These result shows that the designed lateral support structure reaches the design purpose and satisfies the requirements.