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Given a graph L $L$, the Turán number ex(n,L) $\text{ex}(n,L)$ is the maximum possible number of edges in an n $n$‐vertex L $L$‐free graph. The study of Turán number of graphs is a central topic in extremal graph theory. Although the celebrated Erdős‐Stone‐Simonovits theorem gives the asymptotic value of ex(n,L) $\text{ex}(n,L)$ for nonbipartite L $L$, it is challenging in general to determine the exact value of ex(n,L) $\text{ex}(n,L)$ for χ(L)≥3 $\chi (L)\ge 3$. The odd‐ballooning of H $H$ is a graph such that each edge of H $H$ is replaced by an odd cycle and all new vertices of odd cycles are distinct. Here the length of odd cycles is not necessarily equal. The exact value of Turán number of the odd‐ballooning of H $H$ is previously known for H $H$ being a cycle, a path, a tree with assumptions, and K2,3 ${K}_{2,3}$. In this paper, we manage to obtain the exact value of Turán number of the odd‐ballooning of Ks,t ${K}_{s,t}$ with 2≤s≤t $2\le s\le t$, where (s,t)∉{(2,2),(2,3)} $(s,t)\notin \{(2,2),(2,3)\}$ and each odd cycle has length at least five. [ABSTRACT FROM AUTHOR]

Job burnout is an occupational hazard induced by prolonged exposure to excessive work-related stress -a state of physical or emotional exhaustion that also involves a sense of reduced accomplishment and loss of personal identity. Knowledge jobs involve many health-promoting features, but stress and burnout may be caused by the rapid increase in the knowledge intensity of work, new job demands, and emerging new professional subcultures emphasizing the excessive commitment to work. Although there are studies on job burnout and predictors among nurses worldwide, evidence specific to Chinese nurses is lacking. The purpose of this review is to synthesize current research on predictors related to burnout affecting Chinese nurses. We searched the Chinese databases including National Knowledge Infrastructure (CNKI), WanFang, China Science and Technology Journal Database, and Chinese Biological Medical Database (CBM); and international databases including Cochrane Library, PubMed, EMBASE, and Web of Science published up to 30th August 2022. The 125 studies identified assessed a range of predictors of job burnout. The results showed good working relationships and internally controlled individuals were found to be predictive of job burnout. Moreover, numerous predictors produced contradictory data. There are still challenges with how to systematically operationalize such a complicated phenomenon to effectively prevent or reduce job burnout. [ABSTRACT FROM AUTHOR]

Developing chitinase suitable for the bioconversion of chitin to chitin oligosaccharides has attracted significant attention due to its benefits in environmental protection. In this study, chitinase from Aeromonas media CZW001 (AmChi) was purified and characterized. The molecular weight of AmChi was approximately 40 kDa. AmChi exhibited maximum catalytic activity at pH 8.0 with an optimum temperature of 55°C and showed broad stability between 15 and 65°C and between pH 5.0 and 9.0. AmChi was activated by Mg2+, Na+, and K+ and inhibited by Hg+, Co2+, Fe2+, Ca2+, Ag+, Zn2+, and EDTA. The main products of AmChi on colloidal chitin were chitinhexaose and chitinpentaose. AmChi had better substrate specificity for powdered chitin than colloidal chitin and had a higher catalytic efficiency toward (GlcNAc)5 than colloidal chitin. AmChi inhibited fungal growth in a dose‐dependent manner. These results suggest that AmChi could be used for the enzymatic degradation of chitin to produce chitinhexaose and chitinpentaose, which have several industrial applications. [ABSTRACT FROM AUTHOR]

Background: The association of breastfeeding (BF) for postpartum depression (PPD) remains controversial. Currently there are no specific guidelines on the role of BF in the management of PPD.Objectives: To determine the association between BF and PPD.Methods: We searched PubMed, Cochrane Library, and EMBASE up to December 2021 for relevant articles associated between PPD and BF. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with a random-effects model.Results: A total of 8 studies with 18,570 participants were included. BF was associated with a 14% lower risk of PPD (OR 0.86, 95% CI 0.77-0.94, I2 = 51.78%). For a single BF episode, BF duration of >1 month was associated a 37% lower risk (OR 0.63, 95% CI 0.47-0.79, I2 = 34.98%, P = 0.19), and BF for <1 month was associated with a 6% lower risk (OR 0.94, 95% CI 0.89-0.99, I2 = 0.00%, P = 0.61). Exclusive breastfeeding (EBF) compared with never breastfeeding (NBF) was associated with a 53% lower risk for PPD (OR 0.47, 95% CI 0.27-0.66, I2 = 0.00%, P = 0.98). And EBF compared with partial breastfeeding (PBF) was associated with an 8% lower risk for PPD (OR 0.92, 95% CI 0.86-0.98, I2 = 13.86%, P = 0.31). The subgroups we studied may be a source of heterogeneity.Conclusions: Our results show an association between PPD and risk for BF. To confirm the conclusion, more studies with large sample sizes are required. [ABSTRACT FROM AUTHOR]

High-resistance connection (HRC) is a common electrical fault for the electric machine drive system. This fault can lead to the increased power loss and heat, thus possibly causing the damage of the electric machine drive system due to the excessive temperature. Hence, this paper first proposes a vector control strategy of the surface-mounted permanent magnet synchronous machine (PMSM) drive system with the HRC fault to minimize the copper loss. The mathematical model of the PMSM with the HRC is presented in abc stationary frame. The function relationship between the copper loss and the direct axis current, quadrature axis current, stator resistance, and the additional resistance due to the HRC is established and analyzed. The expression of the direct axis current, which minimizes the copper loss, is deduced under the condition of the HRC in one phase and two phases. Consequently, the proposed vector control strategy for the surface-mounted PMSM driving system is achieved. Both the simulation and experimental results show that the proposed method not only preserves the performance of the conventional vector control method, but also can effectively reduce the copper loss, thus protecting the PMSM from the damage due to the increased temperature possibly caused by the HRC fault. [ABSTRACT FROM AUTHOR]

Summer fallow is very common in dryland agriculture to conserve rainwater and replenish soil fertility. However, bare land and intensive rainfall during summer fallow might result in a potential risk of N loss. We used a 15N-labelling method to study the loss of residual N fertilizer during summer fallow and its use by next wheat in the Loess Plateau. Our study included three treatments: without the addition of N (N0W0), with the addition of 50 kg ha−1 N (NW0) and with the addition of 50 kg ha−1 N plus 35% more water (NW). The N fertilizer (K15NO3) in solution was injected into the soil at a depth of 35 cm of the polyvinyl chloride (PVC) columns in field. The fates of 15N were followed after summer fallow and in the next season’s wheat (Triticum aestivum L.). The summer fallow of this study was a dry summer; however, fertilizer 15N was still leached down to 40-cm depth for the NW0 treatment; and for the NW treatment, the peak of 15N fertilizer was approximately 20 cm deeper. After summer fallow, the loss of the initially applied 15N was 26% in the soil profile for the NW0 treatment; and for the NW treatment, it increased to 37%. Soil 15N abundance in 0-20 cm of the NW0 and NW treatments was higher than the N0W0 treatment, indicating the upward movement of 15N in summer fallow. After the next wheat harvest, 15N uptake by wheat in the NW treatment decreased from 21.0 to 18.6% compared to the NW0 treatment. High rainfall during summer fallow increased residual N loss during summer fallow but decreased its use by the next crop. [ABSTRACT FROM AUTHOR]

Abstract: A novel approach to develop high‐performance flexible piezoelectric nanogenerators (PNGs) by using a lead‐free BaTiO3/polydimethyl siloxane (PDMS)/C composite thin film is proposed. The lead‐free BaTiO3 nanoparticles (NPs) are successfully fabricated using a facile modified (nano‐scale precursors) solid‐phase method. The synthesized BaTiO3/PDMS/C composite PNG exhibits an output voltage of approximately 7.43 V with periodically beating from a vibrator, which is increased by 143 % compared to the PNGs without C doping. The maximum power is shown to reach up to approximately 7.92 μW with a load resistance of 2 MΩ when the C content of PNGs is 3.2 wt %.The generated electric energy can be effectively stored by the energy storage capacitor (47 μF) and is successfully used to light a commercial red light‐emitting diode (LED). These results show that the BaTiO3/PDMS/C composite is a promising candidate for large‐scale lead‐free piezoelectric nanogenerator applications. [ABSTRACT FROM AUTHOR]

The article discusses the application of artificial intelligence (AI) in cervical cancer screening. It highlights the severity of cervical cancer as a global health issue, particularly in low- and middle-income countries. The use of AI technology, such as deep learning and machine learning algorithms, has shown promising results in improving the accuracy and efficiency of cervical cancer screening. However, challenges such as the need for diverse and high-quality data, validation in different populations, and adherence to ethical and privacy regulations remain. Overall, the article suggests that AI technology holds promise for improving women's health outcomes in cervical cancer screening, but further research and collaboration are needed. [Extracted from the article]