Сильные и слабые теоремы сходимости для общих задач смешанного равновесия и общих задач вариационного неравенства и задач с фиксированной точкой для двух нерасширяющихся полугрупп в гильбертовых пространствах

Вводятся некоторые итерационные алгоритмы нахождения общего элемента множества решений общей задачи смешанного равновесия и множества решений общего вариационного неравенства для двух коэрцитивных отображений и множества общих неподвижных точек двух нерасширяющихся полугрупп в гильбертовом пространстве. Получены как сильные, так и слабые теоремы сходимости для последовательностей, порожденных этими итерационными процессами в гильбертовых пространствах. Результаты настоящего исследования улучшают и расширяют данные многих других авторов

MicroRNAs control mRNA fate by compartmentalization based on 3 ' UTR length in male germ cells

Post-transcriptional regulation of gene expression can be achieved through the control of mRNA stability, cytoplasmic compartmentalization, 3' UTR length and translational efficacy. Spermiogenesis, a process through which haploid male germ cells differentiate into spermatozoa, represents an ideal model for studying post-transcriptional regulation in vivo because it involves a large number of transcripts that are physically sequestered in ribonucleoprotein particles (RNPs) and thus subjected to delayed translation. To explore how small RNAs regulate mRNA fate, we conducted RNA-Seq analyses to determine not only the levels of both mRNAs and small noncoding RNAs, but also their cytoplasmic compartmentalization during spermiogenesis. Result: Among all small noncoding RNAs studied, miRNAs displayed the most dynamic changes in both abundance and subcytoplasmic localization. mRNAs with shorter 3' UTRs became increasingly enriched in RNPs from pachytene spermatocytes to round spermatids, and the enrichment of shorter 3' UTR mRNAs in RNPs coincided with newly synthesized miRNAs that target these mRNAs at sites closer to the stop codon. In contrast, the translocation of longer 3' UTR mRNAs from RNPs to polysomes correlated with the production of new miRNAs that target these mRNAs at sites distal to the stop codon. Conclusions: miRNAs appear to control cytoplasmic compartmentalization of mRNAs based on 3' UTR length. Our data suggest that transcripts with longer 3' UTRs tend to contain distal miRNA binding sites and are thus targeted to polysomes for translation followed by degradation. In contrast, those with shorter 3' UTRs only possess proximal miRNA binding sites, which, therefore, are targeted into RNPs for enrichment and delayed translation

Few-shot image classification : current status and research trends

Conventional image classification methods usually require a large number of training samples for the training model. However, in practical scenarios, the amount of available sample data is often insufficient, which easily leads to overfitting in network construction. Few-shot learning provides an effective solution to this problem and has been a hot research topic. This paper provides an intensive survey on the state-of-the-art techniques in image classification based on few-shot learning. According to the different deep learning mechanisms, the existing algorithms are di-vided into four categories: transfer learning based, meta-learning based, data augmentation based, and multimodal based methods. Transfer learning based methods transfer useful prior knowledge from the source domain to the target domain. Meta-learning based methods employ past prior knowledge to guide the learning of new tasks. Data augmentation based methods expand the amount of sample data with auxiliary information. Multimodal based methods use the information of the auxiliary modal to facilitate the implementation of image classification tasks. This paper also summarizes the few-shot image datasets available in the literature, and experimental results tested by some representative algorithms are provided to compare their performance and analyze their pros and cons. In addition, the application of existing research outcomes on few-shot image classification in different practical fields are discussed. Finally, a few future research directions are iden-tified. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Involvement of microRNA-93, a new regulator of PTEN/Akt signaling pathway, in regulation of chemotherapeutic drug cisplatin chemosensitivity in ovarian cancer cells

AbstractThe mechanisms underlying ovarian cancer cell resistance to cisplatin (CDDP) are not fully understood. MicroRNAs (miRNAs) play important roles in tumorigenesis and drug resistance. In this paper, we utilized microRNA array and real-time PCR to show that miR-93 is significantly up-regulated in cisplatin-resistant ovarian cancer cells. In vitro assays show that over-expression and knock-down of miR-93 regulate apoptotic activity, and thereby cisplatin chemosensitivity, in ovarian cells. Furthermore, we found that miR-93 can directly target PTEN, and participates in the regulation of the AKT signaling pathway. MiR-93 inversely correlates with PTEN expression in CDDP-resistant and sensitive human ovarian cancer tissues. These results may have implications for therapeutic strategies aiming to overcome ovarian cancer cell resistance to cisplatin

Quasi-MSn identification of flavanone 7-glycoside isomers in Da Chengqi Tang by high performance liquid chromatography-tandem mass spectrometry

<p>Abstract</p> <p>Background</p> <p><it>Da Chengqi Tang </it>(DCT) is a common purgative formula in Chinese medicine. Flavanones are its major active compounds derived from <it>Fructus Aurantii Immaturus</it>. The present study developed an LC-MS/MS method to characterize two pairs of flavanone 7-glycoside isomers, i.e., hesperidin versus neohesperidin and naringin versus isonaringin.</p> <p>Methods</p> <p>After solid phase purification, components in sample were separated on a Agilent zorbax SB-C18 (5 μm, 250 mm × 4.6 mm) analytical column. ESI-MS and quasi-MSⁿwere performed in negative ion mode to obtain structural data of these two pairs of flavanone 7-glycoside isomers. Moreover, UV absorption was measured.</p> <p>Results</p> <p>There was no intra-pairs difference in the UV-Vis and MS/MS spectra of the two pairs of 7-glycoside isomers, whereas the mass spectrometry fragmentation pathways between pairs were different.</p> <p>Conclusion</p> <p>The present study developed a LC-MS/MS method to explore the inter- and intra-pair difference of two pairs of flavanone 7-glycoside isomers.</p

Southern Control of Interhemispheric Synergy on Glacial Marine Carbon Sequestration

Among mechanisms accounting for atmospheric pCO2 drawdown during glacial periods, processes operating in the North Atlantic (NA) and Southern Ocean (SO) have been proposed to be critical. Their individual and synergic effects during a course of glaciation, however, remain enigmatic. We conducted simulations to examine these effects at idealized glacial stages. Under early-glacial-like conditions, cooling in the SO can trigger an initial pCO2 drawdown, while the associated sea ice expansion has little impact on air-sea gas exchange. Under later glacial-like conditions, further cooling in the NA enhances ocean carbon uptake due to a stronger solubility pump, and the SO-induced stronger deep stratification prevents carbon exchange between the deep and upper ocean. Meanwhile, strengthened dust deposition increases the SO contribution to the global biological pump, and CO2 outgassing is suppressed by fully extended sea ice cover. More carbon is then stored in the deep Pacific acting as a passive reservoir