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The interaction between teachers and students is vital for promoting teaching quality. Online learning spaces have various features that can support teacher-student interaction in online learning contexts. In this study, a preliminary model was developed by analyzing the principles underlying the interaction between teachers and students and the support features of online learning spaces. Then, the interaction model was refined and validated in three rounds of teaching practice involving 31 college students. A real-time dynamic artificial intelligence analysis system was used to analyze the teacher-student interaction during three rounds of design-based research. The results showed that the model significantly fostered students’ engagement during the interaction. Moreover, students significantly improved their final exam scores and their innovative problem-solving ability after the intervention.

Ovarian aging refers to the gradual decline of ovarian function with increasing physiological age, manifested as decreased ovarian reserve, elevated aging-related markers, and reduced oocyte quality. With a declining female fertility and a growing aging population, it is urgent to delay ovarian aging to maintain fertility and improve the life quality of women. Theaflavin 3, 3 ′ -digallate (TF3) is a naturally bioactive polyphenol compound extracted from black tea, and its antioxidant properties play an important role in maintaining human health and delaying aging; however, the effects of TF3 on female reproduction and ovarian function are not yet clear. Here, we show that TF3 can preserve primordial follicle pool, partially restore the estrous cycle, and increase the offspring number of aged mice. Meanwhile, TF3 gavage increased the number of oocytes retrieved, decreased the level of reactive oxygen species, increased the level of glutathione, and decreased the abnormal rate of oocyte spindle after ovulation induction. Moreover, TF3 inhibited human granulosa cell apoptosis and improved their antioxidative stress ability. High-throughput sequencing and small-molecule-targeted pharmacological prediction show that TF3 affects multiple pathways and gene expression levels, mainly involved in reproductive and developmental processes. It may also affect cellular function by targeting mTOR to regulate the autophagic pathway, thereby delaying the process of ovarian aging. This study shows that TF3 can be used as a potential dietary supplement to protect ovary function from aging and thereby improving the life quality of advanced-age women.

Hybrid supercapacitors represent a promising candidate for grid-scale energy storage devices because of their excellent high-power density, inherent safety and low cost. Here we report a novel NiSe2@rGO nanocomposite (reduced graphene oxide decorated NiSe2 nanoparticles), which shows high specific capacity of 467 C g-1 at 1 A g-1 and superior rate performance (∼72.8 % of the capacity retention at 20 A g-1). Moreover, a hybrid supercapacitor (HSC) assembled from the NiSe2@rGO positive electrode and rGO negative electrode delivers high energy density (34.3 Wh kg-1) and splendid cycling lifespan (∼93% of the capacity retention over 6500 cycles). This study provides a novel insight on high-performance hybrid supercapacitors.

Although vanadium (V)-based sulfides have been investigated as cathodes for aqueous zinc-ion batteries (ZIBs), the performance improvement and the intrinsic zinc-ion (Zn2+) storage mechanism revelation is still challenging. Here, VS4@rGO composite with optimized morphology is designed and exhibits ultrahigh specific capacity (450 mA h g−1 at 0.5 A g−1) and high-rate capability (313.8 mA h g−1 at 10 A g−1) when applied as cathode material for aqueous ZIBs. Furthermore, the VS4@rGO cathode presents long-life cycling stability with capacity retention of ∼82% after 3500 cycles at 10 A g−1. The structural evolution, redox, and degradation mechanisms of VS4 during (dis)charge processes are further probed by in situ XRD/Raman techniques and TEM analysis. Our results indicate that the main energy storage mechanism is derived from the intercalation/deintercalation reactions in the open channels of VS4. Notably, an irreversible phase transition of VS4 into Zn3(OH)2V2O7·2H2O (ZVO) during the charging process and the further transition from ZVO to ZnV3O8 during long-term cycles are also observed, which might be the main reason leading to the capacity degradation of VS4@rGO. Our study further improves the electrochemical performance of VS4 in aqueous ZIBs through morphology design and provides new insights into the energy storage and performance degradation mechanisms of Zn2+ storage in VS4, and thus may endow the large-scale application of V-based sulfides for energy storage systems.

Chinese Christians in the 1920s faced pressure from a new republic that demanded the loyalty of its citizens despite lacking a proper knowledge of the meaning of the term. Progressive Christians associated with the YMCA soon launched the Citizenship Education Movement in 1924 as they tried to combine Christian virtue with China's broader national demands. While their association of modern citizenship with virtue cultivation was not new, these Christians did attempt something unique, which was to define a good citizen as a world citizen, whose belief in God meant one is loyal ultimately to certain universal values instead of the nation-state. As the Movement continued, the relationship between one's devotion to these higher values and that to the Chinese nation-state remained a complex and often competitive one. Although the Movement ended largely with the end of its visionary, Yu Rizhang, its momentum was harnessed by the Nationalist Party in the New Life Movement. The latter, however, omitted the language of God and universal values at the same time as it injected the nation-state, and the Party in particular, as the sole receiver of loyalty and granter of privilege. Thus the decade-long history of the YMCA's Citizenship Education Movement testifies to the association between one's religious devotion and an internationalist understanding of citizenship.

From the collection of human follicular fluid to the isolation of primary granulosa cells, the duration of these two time points is variable. And there is no specific experiment to explore which temperature will make the cell state better in subsequent experiments. In this study, the collected follicular fluid was divided into 7 groups: one fresh control group, three in vitro storage temperatures (4℃, Room Temperature, and 37℃) and two storage duration times (4h and 8h). After isolating the cells, they were cultured in vitro to evaluate their state and function. The results showed that granulosa cells of the fresh control group had better cell viability and steroid hormone secretion ability than the other treatment groups; with the prolongation of in vitro storage time, the cell viability and steroid hormone secretion ability have decreased to varying degrees; low-temperature in vitro storage is conducive to the maintenance of cell survival and steroid hormone secretion ability, which is also confirmed by the detection of ROS, which can reflect the oxidative stress state of cells. This study showed that after obtaining follicular fluid, the in vitro storage time should be shortened as much as possible, and stored at low temperature, which can keep cells maintain good activity and steroid hormone secretion ability, and reduce oxidative stress and aging. It is of great significance for improving the state of human primary granulosa cells after isolation and subsequent experiment, and it also has certain guiding significance for standardization experimental research programs.

Although vanadium (V)-based sulfides have been investigated as cathodes for aqueous zinc-ion batteries (ZIBs), the performance improvement and the intrinsic zinc-ion (Zn

At present, embryo morphology assessment based on the observation of the embryonic morphological characteristics at several specific time points has been mainly used for selecting the high-quality embryo. However, we all know that embryo development is a dynamic process. Many research results on the correlation between the embryo morphokinetic parameters and embryo quality and development potential were inconsistent. With the help of time-lapse imaging, the development processes and outcomes of a total of 365 embryos were cultured and analyzed in this study. The results showed that the mean tPNf and t2 of the high-quality embryo were significantly shorter than the low-quality embryo; the mean t2PBe and tPNa of the high-quality embryo from the implantation group were significantly shorter than those from the non-implantation group. In addition, based on the quartile grouping of each morphokinetic parameter, the embryos that had 21.15≤tPNf≤25.30 value were significantly higher in embryo quality when compared with the embryos that had the tPNf values outside the range on Days 3. Similarly, the embryos that had values of t2≤25.60 were significantly higher in embryo quality than those with outside the range values on Days 3. Thus, we demonstrated that the morphokinetic parameter evaluated using a time-lapse embryo monitoring system can predict the embryo quality, and be benefit for the selection of the high-quality embryos and improvement for the implantation success of the patient in assisted reproductive technologies.

Backgrounds Long non-coding RNA is a novel group of non-protein coding transcripts over 200 nt in length. Recent studies have found that they are widely involved in many pathological and physiological processes. In our previous study, we found that lnc-GULP1–2:1 was significantly down-regulated in the ovarian cortical tissue of patients with primary ovarian insufficiency and predicted that lnc-GULP1–2:1 has a regulatory effect on COL3A1. Results In this study, we found that lnc-GULP1–2:1 was mainly localized in the cytoplasm of luteinized granulosa cells. The expression of lnc-GULP1–2:1 was lower in patients with diminished ovarian reserve but substantially elevated in patients with polycystic ovary syndrome. Overexpression of lnc-GULP1–2:1 in KGN cells significantly inhibited cell proliferation, likely through cell cycle related genes CCND2 and p16. Moreover, lnc-GULP1–2:1 expression was positively correlated with the level of COL3A in luteinized granulosa cells from patients with different ovarian functions as well as in multiple cell lines. Overexpression of lnc-GULP1–2:1 in KGN cells promoted the expression of COL3A1 and its translocation into the nucleus. Consistently, silencing COL3A1 in KGN cells also significantly inhibited cell proliferation. Conclusions Lnc-GULP1–2:1 affects the proliferation of granulosa cells by regulating the expression and localization of COL3A1 protein, and may participate in the regulation of ovarian follicle development. This study will provide new insight into molecular mechanisms underlying ovarian follicular development, which will help generate novel diagnostic and therapeutic strategies for diseases related to ovarian follicular development disorders.

The interaction between teachers and students is key in promoting knowledge generation and improving teaching quality. Exploring the use of online learning spaces in effectively supporting the teacher-student interaction has important theoretical and practical value. Guided by the interaction equivalency theorem and the generative learning theory, this study adopts literature research and design-based research to build the teacher-student interaction model in online learning spaces. We first formed a preliminary model by analyzing the principles behind the interaction between teachers and students and the support features of online learning spaces. Then, we refined the interaction model during two rounds of teaching practice. To further validate the interaction model, we collected teacher-student interaction data from two online courses and conducted two interaction analyses (i.e., S-T curve and Flanders). Results showed that the model significantly fostered students' engagement during the interaction.

Additional file 2: Supplementary Table 1. The sequences of primers used for real-time PCR

Additional file 1. Sequence and chromosome localization information of Lnc-GULP1–2:1

A disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1) is an extracellular matrix metalloproteinase that plays an important role in the process of ovulation. According to previous studies, the expression level of ADAMTS1 in the granulosa cells of polycystic ovarian syndrome (PCOS) patients and the mechanism for regulating oocyte quality and embryonic development potential are still unclear. Our research clarified that ADAMTS1 was significantly increased in granulosa cells of PCOS patients as compared to ovulatory controls. After silencing ADAMTS1 in granulosa cells, cell proliferation and E2 secretion were significantly inhibited, which may be related to the down-regulation of B-cell lymphoma 2 (Bcl2) family genes and key genes involved in E2 synthesis. Through retrospective analysis of the clinical data, it was found that the expression level of ADAMTS1 was significantly positively correlated to the oocyte maturation rate and good-quality embryo rate in PCOS patients. The downregulation of ADAMTS1 in primary granulosa cells lead to the changes in the expression of marker genes for oocyte and embryonic quality. By using immunofluorescence staining, it was found ADAMTS1 was expressed in various stages of pre-implantation embryo but its expression level gradually decreases with the development of the embryo. In addition, the silence of ADAMTS1 in 3PN zygotes significantly prolonged the development time of the zygote to the morula stage. This is, to our knowledge, the first time to explored the mechanism by which ADAMST1 is involved in affecting the quality of oocytes and embryonic development potential, which will provide new evidence for further understanding of the follicular microenvironment and embryo development.

Mammalian ovarian follicular development is an intricate, elaborate, and well-organized phenomenon regulated by various signaling pathways; however, the underlying mechanism remains unclear. Mammalian sirtuins (sirtuin 1 to sirtuin 7) are a group of NAD+ -dependent deacetylases implicated in various physiological processes including cell proliferation, apoptosis, cell cycle progression, and insulin signaling. Mammalian ovarian sirtuins have been studied using adult and aged bovine, porcine, and murine models. However, limited information is available regarding their precise expression patterns and the localization of follicle development in mice. This study aimed to assess the dynamic expression and localization of all seven sirtuins in early postnatal mouse ovaries through real-time polymerase chain reaction analysis and immunohistochemistry, respectively. During postnatal ovarian follicle development, sirtuin 1, sirtuin 4, and sirtuin 6 were downregulated compared with those in 1-day postnatal mouse ovaries (p < .05), indicating that these three sirtuin genes may be markers of follicular development. Combining their localization in granulosa cells through immunohistochemical studies, sirtuin 1, sirtuin 4, and sirtuin 6 are suggested to play negative regulatory roles in mammal ovarian follicular granulosa cell development. Furthermore, we found that sirtuin 2 (p < .05) and sirtuin 7 (p < .05) mRNA were constantly upregulated relative to sirtuin 1, although limited information is available regarding sirtuin 7. Among all sirtuins in mouse ovaries, sirtuin 1 was relatively and steadily downregulated. Upon sirtuin 1 overexpression in 1-day postnatal mouse ovaries via sirtuin 1-harboring adenoviruses in vitro, the emergence of primary follicles was delayed, as was the emergence of secondary follicles in 4-day postnatal ovaries. Further studies on KGN cell lines reported that interfering with sirtuin 1 expression in granulosa cell significantly affected granulosa cell proliferation and the expression of mitochondrial genes. This study presents the first systemic analysis of dynamic patterns of sirtuin family expression in early postnatal mice ovaries, laying the foundation for further studies on less discussed sirtuin subtypes, such as sirtuin 5 and sirtuin 7.

Seasonal acclimatization is important for animals to live optimally in the varying environment. Phrynocephalus vlangalii, a species of lizard endemic in China, distributes on Qinghai-Tibet Plateau ranging from 2000 to 4600m above sea level. To dissect how this lizard mediate metabolism to adapt various season, the preferred body temperature (Tb), standard metabolic rate (SMR), mitochondrial respiration rates and activities of four metabolic enzymes in this species were tested in different seasons (spring, summer, and autumn). The results showed that the preferred Tb was the lowest in spring and the highest in summer. SMR, maximal mitochondrial respiration rates in liver and skeletal muscle were the highest in spring. Similarly, higher activities of lactate dehydrogenase (LDH), citrate synthase (CS) and cytochrome c oxidase (CCO) activities of liver and skeletal muscle were observed in spring. However, β-hydroxyacyl coenzyme A dehydrogenase (HOAD) activities of liver and skeletal muscle were higher in autumn. On the whole, seasonal variation of metabolism is the highest in spring and the lowest in summer. Seasonal variation of metabolism is the opposite of preferred body temperature, this may be one of the mechanisms to adapt to the environment in P. vlangalii. Our results suggested that P. vlangalii at high altitude has certain adaptive characteristics on metabolism in different seasons.

Constructing nanostructured multiphase composite is an effective way for optimizing the performance of electrode materials. Here we report our findings in design and fabrication of a high-performance electrode material composed of two-phase nickel selenide (NiSe-Ni0.85Se) nanoparticles, which exhibits a high specific capacity of 669 C g−1 at 1 A g−1 and 460 C g−1 at 20 A g−1, indicating its good rate capability (~69%). Moreover, a hybrid supercapacitor composed of NiSe-Ni0.85Se positive electrode and reduced graphene oxide (rGO) negative electrode delivers a specific capacitance of 101 F g−1, high energy of 41 Wh kg−1 and good cycling stability with ~80% capacity retention after 5000 cycles at 10 A g−1. These findings provide an important insight into rational design of nanostructured multiphase nickel selenide materials for energy storage systems.

Battery-supercapacitor hybrid (BSH) device is one of the most promising candidates for next advanced energy storage systems because it can bridge the performance gap between lithium ion batteries and conventional capacitors. Herein, we report a novel porous core-shell structured Fe2O3@Fe3C@C nanochains and urchin-like Ni–Co carbonate hydroxide hybridized (denoted as NiCo–CHH) microspheres for advanced battery-type supercapacitors. The as-obtained Fe2O3@Fe3C@C anode shows high specific capacity (611 C g−1) and good rate capability. The fabricated NiCo–CHH cathode delivers high specific capacity (814 C g−1) and excellent cycling stability. When assembled into a battery-type supercapacitor, the NiCo–CHH//Fe2O3@Fe3C@C device delivers a high energy density (95.2 Wh kg−1) and excellent cycling stability. Moreover, In situ Raman spectroscopy proves the reversibility of the NiCo–CHH electrode, and the synergistic effects of Ni and Co ions, further revealing its energy storage mechanism. These findings provide a novel insight on high-performance battery-type supercapacitors.

Nitric oxide (NO), produced by nitric oxide synthases (NOS) from L-arginine, plays important roles in a wide range of physiological processes. However, little is known about ectothermic species. To investigate the response of NO/NOS system in adaptation to different altitudes in Phrynocephalus genus, the red tail toad-headed lizard Phrynocephalus erythrurus that live at 4500-5300 m on the Qinghai-Tibet Plateau and another low altitude living lizard Phrynocephalus przewalskii were selected in the present study. The results of mRNA expression and activity of NOSs, as well as NO metabolite levels in different tissues of the two lizards indicate that nNOS mRNA levels in cardiac and skeletal muscle were notably elevated in P. erythrurus, and iNOS expression was also increased markedly (up to 4-fold) in cardiac muscle. There was no significant difference in eNOS mRNA level in tested tissues between two species. However, the total NOS activity in skeletal muscle of P. erythrurus was slightly lower than that of P. przewalskii (p .05) while no difference in other tissues. Similarly, lower iNOS activity (p .01) was found in cardiac and skeletal muscle in P. erythrurus compared to P. przewalskii. In addition, the NO metabolite levels were dramatically lower in P. erythrurus in all tested tissues. We propose that higher nNOS and iNOS mRNA expression, lower iNOS activity and NO metabolite levels may represent physiological characteristics in nitric oxide system, which may contribute to high-altitude adaptation in P. erythrurus.

Oxidative stress is a major challenge for the survival of animals living on plateaus; however, lifelong exposure to high altitudes could generate certain adaptabilities which make them more tolerant to these environments. The aim of the present study was to compare the oxidative stress and antioxidant status between low altitude (LA, 2900m) and high altitude (HA, 4200m) populations of Phrynocephalus vlangalii. The results showed that malondialdehyde levels in the HA populations decreased significantly in the brain, but markedly increased in the muscle and had no significant difference in the liver compared to LA populations. The activity of catalase in the brain was much higher in HA than LA. Except for total antioxidant capacity and glutathione reductase, other antioxidants were similar between the two populations in livers. By contrast, the levels of most antioxidants in muscle decreased markedly with elevation. We also explored the effects of hypoxia on oxidative damage and antioxidant defenses in P. vlangalii. The lizards were acclimated in a simulated hypoxic chamber (15% O2 and 8% O2) for 6weeks. The results showed that in the 8% O2 group, the levels of malondialdehyde, catalase, glutathione and total antioxidant capacity in the brain, and malondialdehyde, catalase and superoxide dismutase in the liver were significantly higher than the 15% O2 group. These findings indicate that in this species the oxidative stress and antioxidant capacity are subject to altitude and hypoxia and this lizard may have acquired some ability to deal with the oxidative stress.

Phrynocephalus erythrurus (Lacertilia: Agamidae) is considered to be the highest living reptile in the world (about 4500-5000 m above sea level), whereas Phrynocephalus przewalskii inhabits low altitudes (about 1000-1500 m above sea level). Here, we report the differences in hematological traits between these two different Phrynocephalus species. Compared with P. przewalskii, the results indicated that P. erythrurus own higher oxygen carrying capacity by increasing red blood cell count (RBC), hemoglobin concentration ([Hb]) and hematocrit (Hct) and these elevations could promote oxygen carrying capacity without disadvantage of high viscosity. The lower partial pressure of oxygen in arterial blood (PaO2) of P. erythrurus did not cause the secondary alkalosis, which may be attributed to an efficient pulmonary system for oxygen (O2) loading. The elevated blood-O2 affinity in P. erythrurus may be achieved by increasing intrinsic O2 affinity of isoHbs and balancing the independent effects of potential heterotropic ligands. We detected one α-globin gene and three β-globin genes with 1 and 33 amino acid substitutions between these two species, respectively. Molecular dynamics simulation results showed that amino acids substitutions in β-globin chains could lead to the elimination of hydrogen bonds in T-state Hb models of P. erythrurus. Based on the present data, we suggest that P. erythrurus have evolved an efficient oxygen transport system under the unremitting hypobaric hypoxia.

Two new methods to improve the ultra-low speed control performance of ac servo system are described in this paper. One is improved M/T method, which could minimize the influence of speed detection dead time and smooth the measurement. Another is instantaneous speed detection based on constant jerk model, which assumes the rotor jerk is constant at the interval of sampling period. The instantaneous speed is calculated by analytic geometry. This method can minimize both the speed detection dead time and detection delay, which is the premise of low-speed control. The effectiveness of these methods has been confirmed by experimentation. The experimental system is composed of a digital signal processor (DSP), a field programmable gate array (FPGA), a PWM inverter and a permanent magnet synchronous motor (PMSM).