The Relationship between Bone Remodeling and the Clockwise Rotation of the Facial Skeleton: A Computed Tomographic Imaging-Based Evaluation

Background: Information on the onset and gender differences of midfacial skeletal changes, including the complete understanding of the theory behind the clockwise rotational theory, remains elusive. Methods: One hundred fifty-seven Caucasian individuals (10 men and 10 women aged 20 to 29 years, 30 to 39 years, 40 to 49 years, 50 to 59 years, 60 to 69 years, 70 to 79 years, and 80 to 89 years, and eight men and nine women aged 90 to 98 years) were investigated. Multiplanar computed tomographic scans with standardized angle and distance measurements in all three anatomical axes and in alignment to the sella-nasion (horizontal) line were conducted. Results: Both men and women displayed an increase in orbital floor angle (p < 0.001, maximum at 60 to 69 years), decrease in maxillary angle (p = 0.035, 40 to 49 years), increase in palate angle (p < 0.001, 50 to 59 years), increase in vomer angle (p = 0.022, 30 to 39 years), but a decrease in the pterygoid angle (p = 0.002, 80 to 89 years). Orbital width decreased (p < 0.001, 60 to 69 years), pyriform aperture width increased (p = 0.015, 60 to 69 years), and midfacial height decreased with aging (p < 0.001, 60 to 69 years). Conclusions: Age-related changes of the midfacial skeleton occurred independently of gender, but at various time points in different locations. The observed changes seem to be driven by a bone resorption center located in the posterior maxilla, rather than by a rotational movement of the facial skeleton

Ультранизкодозная компьютерная томография в диагностике заболеваний околоносовых пазух у детей: обзор литературы

Background. Sinonasal diseases are widespread in childhood. Radiological studies, including computer tomography, are an optimal and effective method of diagnosis. The child's body is more sensitive to radiation exposure than adults. The threshold of exposure, which may induce internal organs injury in children, requires a precise selection of the radiological method with minimal radiation dose. There is currently no unified position in the professional community on the appropriateness of the use of ultra-low-dose computed tomography in pediatrics.We reviewed the data on the appropriateness and effectiveness of paranasal low-dose computed tomography in pediatrics.Materials. 57 domestic and foreign publications, for the period from January 2001 to November 2019. In order to achieve the objective, we analyzed relevant domestic and foreign publications in scientific libraries e-LIBRARY, PubMed, Google Scholar per the keywords: “low-dose CT”, “children”, “paranasal sinus”, “pediatric”, “diagnosis”, “children”, “low-dose computed tomography”, “sinusitis”, “paranasal sinuses”.Results. The analysis of the available literature allowed summarizing the current data on pediatric paranasal disease diagnostics and the use of computed tomography, as well as to identify possible options for reducing radiation dose.Conclusions. Conducting many radiological examinations in a child leads to the risk of cancer. However, these examinations are an effective way to diagnose paranasal diseases, and a CT scan is the “gold standard”. The actual task is to develop a CT technique with reduced radiation exposure without compromising image quality. The need to review and optimize the standard protocols of radiological studies to determine the efficacy and feasibility of studies with minimal radiation exposure to children is justified.Актуальность. Заболевания придаточных пазух носа широко распространены в детском возрасте. Рентгенологические исследования, и в том числе рентгеновская компьютерная томография (КТ), являются оптимальным и эффективным методом диагностики. Организм ребенка более чувствителен к радиационной нагрузке, чем взрослых. Порог облучения, который может индуцировать поражение внутренних органов у детей, требует четкого выбора методики рентгенологического исследования с минимальной радиационной нагрузкой. В профессиональном сообществе в настоящее время отсутствует единая позиция по вопросу целесообразности применения ультранизкодозной КТ в педиатрии.Цель исследования: систематизация данных о целесообразности и эффективности применения низкодозной КТ при диагностике заболеваний околоносовых пазух в педиатрии.Материал и методы. Для выполнения поставленной цели проведен анализ 57 релевантных отечественных и зарубежных публикаций за период с января 2001 г. по ноябрь 2019 г. в научных библиотеках eLIBRARY, PubMed, Scholar.google по ключевым словам: “lowdose CT”, “children”, “paranasalsinus”, “pediatric”, “диагностика”, “дети”, “низкодозная компьютерная томография”, “синусит”, “околоносовые пазухи”.Результаты. Изучение опубликованных в доступной литературе результатов исследований разных авторов позволило обобщить современные данные о лучевой диагностике заболеваний околоносовых пазух у детей и использовании КТ, а также определить возможные варианты снижения дозы лучевой нагрузки.Заключение. Проведение большого количества рентгенологических исследований у ребенка приводит к риску развития онкологических заболеваний. Вместе с тем именно рентгенологические исследования являются эффективным способом диагностики заболеваний околоносовых пазух, при этом КТ является “золотым стандартом” диагностических исследований. Актуальной задачей является разработка методики КТ со снижением радиационной нагрузки без потери качества изображения. В обзоре изученных научных работ обоснована необходимость пересмотра и оптимизации стандартных протоколов рентгенологических исследований околоносовых пазух для определения эффективности и целесообразности методик лучевых исследований с минимальным риском радиационной нагрузки на ребенка

Examining the moderating role of environmental practices in the relationship between service quality and customer experience among hotel sectors

Upscale hotels work in a market with a lot of competition, so they put a lot of emphasis on providing good service and standing out through the value of the customer experience. People have said that consumers' thoughts and actions change over time and depend on what they need at any given time. Hotels try to give their customers a unique experience by listening to what they want. There's no doubt that customer behaviour has changed along with the growth of technology, which has made people's lives much easier. Therefore, hoteliers need to know what their customer want and which technological facilities will delight them. A review of the literature shows that guests like the way technology in service delivery has improved the quality of service in hotels. Studying how present service quality impacts customer experience and how technologies might improve service quality is an interest of this research. The study also looks at environmental practices that can strengthen the effect of service quality factors on customer experience. Because of this, the research suggests that we look into possible moderating variables that could help make hotel service better for customers. This study makes use of quantitative methods. 150 questionnaires were successful, and valid answers were used as samples. While this study uses Means-End Chain theory to map and place possible relationships between variables in a conceptual framework. The results show that the most important thing for meeting customer expectations is the quality of the interaction followed by the physical environment quality and outcome quality. The current study finding the positive moderating effect of environmental practices among Malaysian hotels. Empirical research concludes that customers’ experiences specified by lengths of relationships with a service provider. The results also have consequences for managers responsible of service operations and show that putting in certain new technologies can have a big effect on how customers feel about a business

Progress in Piezoelectric Nanogenerators Based on PVDF Composite Films

In recent years, great progress has been made in the field of energy harvesting to satisfy increasing needs for portable, sustainable, and renewable energy. Among piezoelectric materials, poly(vinylidene fluoride) (PVDF) and its copolymers are the most promising materials for piezoelectric nanogenerators (PENGs) due to their unique electroactivity, high flexibility, good machinability, and long–term stability. So far, PVDF–based PENGs have made remarkable progress. In this paper, the effects of the existence of various nanofillers, including organic–inorganic lead halide perovskites, inorganic lead halide perovskites, perovskite–type oxides, semiconductor piezoelectric materials, two–dimensional layered materials, and ions, in PVDF and its copolymer structure on their piezoelectric response and energy–harvesting properties are reviewed. This review will enable researchers to understand the piezoelectric mechanisms of the PVDF–based composite–film PENGs, so as to effectively convert environmental mechanical stimulus into electrical energy, and finally realize self–powered sensors or high–performance power sources for electronic devices

Progress in Piezoelectric Nanogenerators Based on PVDF Composite Films

In recent years, great progress has been made in the field of energy harvesting to satisfy increasing needs for portable, sustainable, and renewable energy. Among piezoelectric materials, poly(vinylidene fluoride) (PVDF) and its copolymers are the most promising materials for piezoelectric nanogenerators (PENGs) due to their unique electroactivity, high flexibility, good machinability, and long–term stability. So far, PVDF–based PENGs have made remarkable progress. In this paper, the effects of the existence of various nanofillers, including organic–inorganic lead halide perovskites, inorganic lead halide perovskites, perovskite–type oxides, semiconductor piezoelectric materials, two–dimensional layered materials, and ions, in PVDF and its copolymer structure on their piezoelectric response and energy–harvesting properties are reviewed. This review will enable researchers to understand the piezoelectric mechanisms of the PVDF–based composite–film PENGs, so as to effectively convert environmental mechanical stimulus into electrical energy, and finally realize self–powered sensors or high–performance power sources for electronic devices

Polarization-Sensitive Light Sensors Based on a Bulk Perovskite MAPbBr3 Single Crystal

Organic-inorganic halide perovskites have attracted much attention thanks to their excellent optoelectronic performances. Here, a bulk CH3NH3PbBr3 (MAPbBr3) single crystal (SC) was fabricated, whose temperature and light polarization dependence was investigated by measuring photoluminescence. The presence of obvious band tail states was unveiled when the applied temperature was reduced from room temperature to 78 K. Temperature dependence of the bandgap of the MAPbBr3 SC was found to be abnormal compared with those of traditional semiconductors due to the presence of instabilization of out-of-phase tail states. The MAPbBr3 SC revealed an anisotropy light absorption for linearly polarized light with an anisotropy ratio of 1.45, and a circular dichroism ratio of up to 9% was discovered due to the spin-orbit coupling in the band tail states, exhibiting great polarization sensitivity of the MAPbBr3 SC for the application of light sensors. These key findings shed light on the development of potential optoelectronic and spintronic applications based on large-scaled organic-inorganic perovskite SCs