Research on the Application of Computational Materials Science in Undergraduate Teaching

In this paper, by taking first-principles software as examples, we apply computational materials science to the teaching process of undergraduates majoring in physics, chemistry and materials. We pay attention to the connection between theoretical research and experimental models, makes the abstract principle intuitive and dynamic, and facilitates students’ understanding of knowledge, a deep understanding of the structure of materials and the relationship between theoretical properties and macro properties, which can greatly enhance students’ initiative and creativity in participating in teaching activities. To a great extent, this has played a role of computational simulation as a bridge between theoretical teaching and experimental teaching to continue to explore the complementary relationship between computational simulation, theoretical teaching and experimental teaching, build a teaching model for the application and design ability training of materials and chemistry talents

Identificación de las especies: Ommastrephes bartramii, Dosidicus gigas, Sthenoteuthis oualaniensis e Illex argentinus (Ommastrephidae) a través de medidas morfológicas de sus picos

Four oceanic squid species, Ommastrephes bartramii, Dosidicus gigas, Sthenoteuthis oualaniensis and Illex argentinus, not only support important commercial fisheries, but also play a vital role in their marine ecosystems. It is therefore important to identify them in the analyses of their predators’ stomach contents as this can yield critical information on the trophic dynamics of ecosystems. Hard beaks of the four species frequently found in their predators’ stomachs can be used to identify them. In this study, to remove the effect of size differences among individuals, measurements of upper and lower beaks were standardized with an allometric model. A discriminant analysis was carried out to compare morphological differences among the four species and between the sexes for each species. The upper rostral width and upper rostral length showed the greatest interspecific variation in the beak morphological variables of the four Ommastrephidae. The linear discriminant functions of beak morphological variables were developed for the four Ommastraphidae, which resulted in a rate of correct species classification of over 97%. Sexual dimorphism was also found in the beak morphology of O. bartramii and I. argentinus. This study suggests that morphological variables can be used to reliably classify Ommastrephidae at genus level, which can help identify the specie in the stomachs of cephalopod predators. This helps to improve the understanding of the role cephalopods play in their marine ecosystems.Las cuatro especies de calamares: Ommastrephes bartramii, Dosidicus gigas, Sthenoteuthis oualaniensis e Illex argentinus, sometidas a una importante presión pesquera, juegan un papel significativo dentro de los ecosistemas marinos a los que pertenecen. Al ser los picos de estas especies resistentes, las medidas de diversos aspectos de su morfología pueden servir para identificarlas en análisis de contenidos estomacales de sus depredadores. Ello permite obtener una información crucial sobre la dinámica trófica de los ecosistemas. En el presente estudio, las medidas realizadas en los picos superior e inferior de los Ommastrephidae se han normalizado mediante un modelo de crecimiento alométrico, para evitar la influencia del efecto tamaño de los individuos. A continuación, mediante un análisis discriminante, se han estudiado las diferencias morfológicas entre las cuatro especies, así como entre machos y hembras. Las medidas que presentaban mayores variaciones eran la anchura y longitud del rostro superior. Mediante funciones discriminantes lineales de las medidas morfológicas normalizadas de sus picos, se han conseguido clasificar las cuatro especies de Ommastraphidae, con una fiabilidad superior al 97%. Asimismo, a través de sus medidas morfológicas, se ha encontrado un claro dimorfismo sexual en los picos de O. bartramii e I. argentinus. El presente estudio sugiere que las medidas morfológicas pueden ser útiles para clasificar correctamente los Ommastrephidae a nivel de género, y puede permitir identificar la especie en contenidos estomacales de depredadores de cefalópodos, lo cual mejorará el conocimiento del papel de los cefalópodos en los ecosistemas marinos en los que se integran

Modelos lineales generalizados bayesianos para la estandardización de CPUE: aplicación a la pesquería de calamar mediante jigging en el Pacífico noroccidental

Generalized linear Bayesian (GLBM) non-hierarchical and hierarchical models were developed for standardization of catch per unit effort (CPUE). The GLBM containing the covariates of month, latitude, sea surface temperature (SST), sea surface salinity (SSS) and sea level height (SLH) had the best fit for the Chinese squid-jigging fishery of Ommastrephes bartramii in the northwest Pacific Ocean based on deviance information criteria. This best-fitting model tends to be more ecologically sound than other CPUE standardization models, such as generalized linear models and generalized additive models. GLBM was also used to deal with the problems of estimating stock abundance index (i.e. standardized CPUE) resulting from increased spatial heterogeneity of spatial dynamics of fishing efforts in the squid fishery by predicting the standardized CPUE for unfished areas. The standardized CPUE based on data including predicted CPUE of unfished areas was lower than the derived CPUE based on data with observed CPUE alone, in particular during the fishing peak of August to October. This study indicates that it is more appropriate to use the standardized CPUE derived from data including both predicted CPUE of unfished areas and observed CPUE of fished area as a stock abundance index. We suggest that the proposed method be used in CPUE standardization to account for impacts of large spatial heterogeneity of fishing efforts in fisheries.Se desarrollan modelos lineales generalizados bayesianos (GLBM) jerárquicos y no-jerárquicos para la estandardización de captura por unidad de esfuerzo (CPUE). El modelo GLBM seleccionado para la pesquería del calamar Ommastrephes bartramii mediante jigging en el Pacífico noroccidental incorporó las variables explicativas mes, latitud, temperatura superficial del mar (SST), salinidad superficial del mar (SSS) y altura del nivel del mar (SLH). La selección del modelo se basó en el Criterio de Información de la Desviación (DIC). El modelo que mejor se ajustó a los datos tiene más sentido ecológico comparado con modelos de estandardización de CPUE basado en modelos lineales generalizados y modelos aditivos generalizados. Se utilizó también el GLBM para tratar el problema de la estimación de un índice de abundancia del stock (es decir, CPUE estandardizada) frente a la elevada heterogeneidad espacial en la dinámica del esfuerzo en la pesquería del calamar mediante la predicción de la CPUE estandardizada en áreas no pescadas. La CPUE estandardizada en base a los datos que incluyen la CPUE predicha en áreas no pescadas fue inferior a la CPUE derivada en base solamente a la CPUE observada, especialmente durante el pico de pesca de Agosto a Octubre. Este estudio muestra que es más apropiado usar la CPUE estandardizada derivada de datos que incluyen al mismo tiempo la CPUE predicha de las áreas no pescadas y la CPUE observada en el área pescada como índice de abundancia del stock. Se sugiere que se use el método propuesto para la estandardización de CPUE teniendo en cuenta la gran heterogeneidad espacial del esfuerzo pesquero

Hierarchical control strategy for unbalanced voltage in an islanded microgrid

When the microgrid is running in an islanded mode, unbalanced loads result in microgrid voltage unbalance. The voltage unbalance factor at the Point of Common Coupling (PCC) is a key parameter in measurement of microgrid power quality. To improve microgrid power quality, many documents utilize micro-source voltage measurement results to help adjust the unbalance factor of microgrid voltage. However, due to line impedance presence, there are differences between micro-source output voltage and PCC voltage. Therefore, it is impossible for a micro-source to control the unbalance factor of PCC voltage with high precision by measuring its own output voltage. Based on equivalent circuit, the present paper analyzes the negative sequence component relationship among micro-source output voltage, line impedance voltage drop, and PCC voltage. It further proposes a hierarchical-control-based method to control the unbalance factor of PCC voltage with high accuracy, and analyzes the impact of secondary control delay on system stability by root locus calculating. Finally, the control strategy is validated in an islanded microgrid system with two micro-sources. The experimental results show the effectiveness and feasibility of the proposed control strategy.Під час роботи мікроенергосистеми (МЕ) в ізольованому режимі незбалансовані навантаження призводять до дисбалансу напруги у ній. Фактор дисбалансу напруги у точці спільного приєднання (ТСП) є основним параметром при вимірюванні якості електроенергії МЕ. Для підвищення якості електроенергії МЕ використовують результати вимірювань напруги мікроджерел для врегулювання фактора дисбалансу напруги МЕ. Проте через наявність повного вхідного опору лінії існують відмінності між вихідною напругою мікрождерела та напругою ТСП. Тому мікроджерело не може контролювати фактор дисбалансу напруги ТСП з високою точністю шляхом вимірювання власної вихідної напруги. На базі еквівалентної схеми у даній статті аналізуються відношення складової оберненої послідовності між вихідною напругою мікроджерела, падінням напруги повного вхідного опору лінії та напругою у ТСП. Також для контролю фактора дисбалансу напруги ТСП із високою точністю пропонується метод на основі ієрархічного контролю, аналізується вплив затримки вторинного контролю на стабільність системи. Стратегія контролю перевірялася в ізольованій мікроенергосистемі з двома мікроджерелами. Дослідні дані показують ефективність та доцільність запропонованої стратегії контролю.При работе микроэнергосистемы (МЭ) в изолированном режиме несбалансированые нагрузки приводят к дисбалансу напряжения в ней. Фактор дисбаланса напряжения в точке общего присоединения (ТОП) является основным параметром при измерении качества электроэнергии МЭ. Для улучшения качества электроэнергии МЭ используют результаты измерений напряжения микроисточников для урегулирования дисбаланса напряжения МЭ. Однако из-за наличия полного входного сопротивления линии существуют различия между выходным напряжением микроисточника и напряжением ТОП. Поэтому микроисточник не может контролировать дисбаланс напряжения ТОП с высокой точностью путем измерения собственного выходного напряжения. На основании эквивалентной схемы в данной статье анализируется отношение составляющей обратной последовательности между выходным напряжением микроисточника, падением напряжения полного входного сопротивления линии и напряжением в ТОП. Также для контроля фактора дисбаланса напряжения ТОП с высокой точностью предлагается метод на основе иерархического контроля, анализируется влияние задержки вторичного контроля на стабильность системы. Стратегия контроля проверялась в изолированной микроэнергосистеме с двумя микроисточниками. Опытные данные показывают эффективность и целесообразность предлагаемой стратегии контроля

Liver organoids: a promising three-dimensional model for insights and innovations in tumor progression and precision medicine of liver cancer

Primary liver cancer (PLC) is one type of cancer with high incidence rate and high mortality rate in the worldwide. Systemic therapy is the major treatment for PLC, including surgical resection, immunotherapy and targeted therapy. However, mainly due to the heterogeneity of tumors, responses to the above drug therapy differ from person to person, indicating the urgent needs for personalized treatment for PLC. Organoids are 3D models derived from adult liver tissues or pluripotent stem cells. Based on the ability to recapitulate the genetic and functional features of in vivo tissues, organoids have assisted biomedical research to make tremendous progress in understanding disease origin, progression and treatment strategies since their invention and application. In liver cancer research, liver organoids contribute greatly to reflecting the heterogeneity of liver cancer and restoring tumor microenvironment (TME) by co-organizing tumor vasculature and stromal components in vitro. Therefore, they provide a promising platform for further investigation into the biology of liver cancer, drug screening and precision medicine for PLC. In this review, we discuss the recent advances of liver organoids in liver cancer, in terms of generation methods, application in precision medicine and TME modeling

Genetic characterization and virulence determinants of multidrug-resistant NDM-1-producing Aeromonas caviae

The emergence of carbapenemase significantly threatens public health. It is prevalent worldwide but rare in Aeromonas caviae. Unlike most bacterial species, A. caviae has two distinct flagella systems, which are closely related to biofilm formation. The ability to form biofilms on host tissues or inert surfaces constitutes an important cause of many persistent infections, which causes difficulties in clinical treatment. Here, we report on a multidrug-resistant (MDR) A. caviae carrying blaNDM–1 with a novel sequence type 1,416. The strong ability of biofilm formation of FAHZZU2447 was verified by a crystal violet assay. The resistome profile and location of the blaNDM–1 gene were determined by antimicrobial susceptibility testing, S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), and Southern blot analysis. Moreover, the strain underwent whole-genome sequencing to identify its genomic characteristics. In addition, the blaNDM–1 gene was located on a ∼243 kb plasmid with genetic context IS1R-blaNDM–1-ble-trpF-dsbD-hp-sul1-qacE. Phylogenetic analysis indicated the transmission of A. caviae in China, Japan, and Thailand. Our study aimed to elucidate the genomic features of blaNDM–1-producing A. caviae, thereby clarifying the distribution of A. caviae worldwide and emphasizing the harmfulness of biofilm formation to the clinic. Further comprehensive surveillance of this species is needed to control further dissemination

Olmesartan Attenuates the Impairment of Endothelial Cells Induced by Oxidized Low Density Lipoprotein through Downregulating Expression of LOX-1

Oxidized low density lipoprotein (ox-LDL) and its receptor, lectin-Like ox-LDL receptor-1 (LOX-1), play important roles in the development of endothelial injuries. Olmesartan can protect endothelial cells from the impairment caused by various pathological stimulations. In the present study we investigated whether olmesartan decreased the impairment of endothelial cells induced by ox-LDL by exerting its effects on LOX-1 both in vitro and in vivo. Incubation of cultured endothelial cells of neonatal rats with ox-LDL for 24 h or infusion of ox-LDL in mice for 3 weeks led to the remarkable impairment of endothelial cells, including increased lactate dehydrogenase synthesis, phosphorylation of p38 mitogen-activated protein kinases (p38 MAPK) and expression of apoptotic genes such as B-cell leukemia/lymphoma 2 (Bcl-2)-associated X protein (Bax) and caspase-3. Simultaneously, the cell vitality and expression of Bcl-2 gene were greatly reduced. All these effects, however, were significantly suppressed by the treatment with olmesartan. Furthermore, ox-LDL promoted up-regulation of LOX-1 expression either in cultured endothelial cells or in the aortas of mice, which was reversed with the administration of olmesartan. Our data indicated that olmesartan may attenuate the impairment of endothelial cell via down-regulation of the increased LOX-1 expression induced by ox-LDL