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Abstract Background Schizochytrium sp. is commercially used for production of docosahexaenoic acid (DHA). Schizochytrium sp. utilizes the polyketide synthase complex (PKS) and a single type I fatty acid synthase (FAS) to synthesize polyunsaturated fatty acids and saturated fatty acids, respectively. The acyl carrier protein (ACP) domains of FAS or PKS are used to load acyl groups during fatty acids biosynthesis. Phosphopantetheinyl transferase (PPTase) transfers the pantetheine moiety from Coenzyme A to the conserved serine residue of an inactive ACP domain to produce its active form. Results In this study, in order to improve production and content of DHA, we decreased the expression of fas, strengthened the expression of the PKS pathway, and enhanced the supply of active ACP in Schizochytrium sp. ATCC20888. Weakening the expression of fas or disruption of orfA both led to growth defect and reduction of lipid yields in the resulting strains WFAS and DPKSA, indicating that both FAS and PKS were indispensable for growth and lipid accumulation. Although WFAS had a higher DHA content in total fatty acids than the wild-type strain (WT), its growth defect and low DHA yield hinders its use for DHA production. Overexpression of the orfAB, orfC, orfC-DH (truncated orfC), or ppt promoted DHA and lipid production, respectively. The yields and contents of DHA were further increased by combined overexpression of these genes. Highest values of DHA yield (7.2 g/L) and DHA content (40.6%) were achieved in a recombinant OPKSABC-PPT, ⁓56.5% and 15.3% higher than the WT values, respectively. Conclusions This study demonstrates that genetic engineering of the fatty acid biosynthetic pathways provides a new strategy to enhance DHA production in Schizochytrium.

The hydrogen absorption/desorption kinetic properties of MgH2 can be effectively enhanced by doping specific catalysts. In this work, MOFs-derived NiCu@C nanoparticles (∼15 nm) with regular core-shell structure were successfully prepared and introduced into MgH2 (denoted as MgH2NiCu@C). The onset and peak temperatures of hydrogen desorption of MgH2–11 wt.% NiCu@C are 175.0 °C and 282.2 °C, respectively. The apparent activation energy of dehydrogenated reaction is 77.2 ± 4.5 kJ/mol for MgH2–11 wt.% NiCu@C, which is lower than half of that of the as-milled MgH2. Moreover, MgH2–11 wt.% NiCu@C displays great cyclic stability. The strengthening “hydrogen pumping” effect of reversible solid solutions Mg2Ni(Cu)/Mg2Ni(Cu)H4 is proposed to explain the remarkable improvement in hydrogen absorption/desorption kinetic properties of MgH2. This work offers a novel perspective for the design of bimetallic nanoparticles and beyond for application in hydrogen storage and other energy related fields.

Abstract Background Vaginectomy has been shown to be effective for select patients with vaginal high-grade squamous intraepithelial lesions (HSIL) and is favored by gynecologists, while there are few reports on the robotic-assisted laparoscopic vaginectomy (RALV). The aim of this study was to evaluate the safety and treatment outcomes between RALV and the conventional laparoscopic vaginectomy (CLV) for patients with vaginal HSIL. Methods This retrospective cohort study was conducted in 109 patients with vaginal HSIL who underwent either RALV (RALV group) or CLV (CLV group) from December 2013 to May 2022. The operative data, homogeneous HPV infection regression rate and vaginal HSIL regression rate were compared between the two groups. Student’s t-test, the Mann-Whitney U test, Pearson χ2 test or the Fisher exact test, Kaplan-Meier survival analysis and Cox proportional-hazards models were used for data analysis. Results There were 32 patients in the RALV group and 77 patients in the CLV group. Compared with the CLV group, patients in the RALV group demonstrated less estimated blood loss (41.6 ± 40.3 mL vs. 68.1 ± 56.4 mL, P = 0.017), lower intraoperative complications rate (6.3% vs. 24.7%, P = 0.026), and shorter flatus passing time (2.0 (1.0–2.0) vs. 2.0 (2.0–2.0), P 0.999) and vaginal HSIL regression rate (96.7% vs. 94.7%, P = 0.805) after vaginectomy. However, the RALV group had significantly higher hospital costs than that in the CLV group (53035.1 ± 9539.0 yuan vs. 32706.8 ± 6659.2 yuan, P

Two-dimensional Ti3C2Tx MXenes exposing different active facets are introduced into MgH2, and their catalytic effects are systematically investigated in depth through experimental and theoretical approaches. Excluding factors such as interlayer space, surface functional groups and experimental contingency, the exposed facets is considered to be the dominant factor for catalytic activity of Ti3C2Tx towards MgH2. More exposed edge facets of Ti3C2Tx displays higher catalytic activity than that with more exposed basal facets, which also leads to different rate-controlling steps of MgH2 in the de/hydrogenation process. The low work function, strong hydrogen affinity and high content of in situ metallic Ti for the edge facet contribute the high catalytic activity. This work will give insights into the structural design of two-dimensional Ti3C2Tx MXene used for enhancing the catalytic activity in various fields.

Abstract Background Antimicrobial resistance is a threat to global public health and requires the development of new antibiotic alternatives to treat bacterial infection. Infection with Escherichia coli (E. coli) is the most common cause of diarrhea in pigs, especially in weaning piglets. The objective of this study was to characterize chemical properties of water-soluble extract (WSE) obtained from yeast cell wall, and study its antibacterial activity and antimicrobial mechanisms against E. coli. Results WSE was extracted from yeast cell wall by hot water, followed by anhydrous ethanol precipitation and deproteinization by Sevag method to obtain water-soluble polysaccharides (WSP, accounting for 76.53 ± 5.91% by weight of WSE). WSP was purified by DEAE-52 cellulose column and Sephadex G-100 column to obtain three fractions of polysaccharides, WSNP, WSAP-1 and WSAP-2. Physicochemical properties of them were then characterized. The average molecular weights of WSNP, WSAP-1 and WSAP-2 were 105,130, 94,581 and 91,247 Da, respectively. WSNP was composed of glucosamine (GlcN), glucose (Glc), mannose (Man) and glucuronic acid (GlcA) in a molar ratio of 8.6:55.2:34.4:1.8, WSAP-1 was consisted of GlcN, Glc and Man in a molar ratio of 10.9:42.2:46.9, and WSAP-2 was consisted of GlcN, galactose (Gal), Glc and Man in a molar ratio of 9.0:1.0:55.1:34.9. Spectral analysis indicated that all three polysaccharides had pyran polysaccharides, triple-helix structure, α- and β-glycosidic bond. The minimum inhibitory concentrations of WSE and WSP on E.coli were 25 mg/mL and 100 mg/mL, respectively. WSE can not only disrupt the integrity of the cell wall and membrane of E.coli, but also increase the permeability of the outer membrane. Conclusions Our research elucidated chemical composition and structure of WSNP, WSAP-1 and WSAP-2. WSE exerted its bactericidal activity by damaging the bacterial cell wall and membrane and increasing outer membrane permeability. Yeast cell wall products have been recommended as a potential alternative to antibiotics. This work provides more information, regarding chemical properties and anti-E. coli mechanism of WSE, and facilitates the application of yeast cell wall products as a promising antibiotic alternative in animal feed.

In order to clarify water migration and textural changes in oil-tea camellia seeds during fresh storage after harvest, low-field nuclear magnetic resonance and magnetic resonance imaging techniques were used to clarify moisture state and distribution law and textural profile analysis was used to monitor the changes in the texture characteristics taking the oil-tea camellia seeds produced in Guizhou Province as test materials. And correlation analysis was carried out. The results showed that the water content of the oil-tea camellia seeds decreased continuously during storage. The water content of Qianyu 1 decreased from 33.86%±3.03% (0 d) to 8.64%±0.24% (56 d), and that of Xianglin 210 decreased from 53.03%±3.36% (0 d) to 10.73%±0.25% (56 d). The rate of decrease in kernel water content was higher than that of the oil-tea camellia seeds. The proportion of non-flowable water was the highest in the oil-tea camellia seeds, whereas that in Qianyu 1 decreased to 62.89% and that in Xianglin 210 decreased to 60.64% after 56 d of storage. The hydrogen proton density image of the fresh oil-tea camellia seeds was bright. Local water loss increased as storage time was prolonged, and the image gradually approached the background color. The fracture and hardness properties of the oil-tea camellia seeds decreased continuously during storage, and that of the seed kernels changed flexural; The springiness of the seed kernels was gradually lost; The cohesiveness of Qianyu 1 changed slightly, while that of Xianglin 210 increased first and then decreased. Correlation analysis revealed a very extremely significant positive correlation between the water content and the total peak area of oil-tea camellia seeds (P

Abstract Light metal hydrolysis for hydrogen supply is well suited for portable hydrogen fuel cells. The addition of catalysts can substantially aid Mg hydrolysis. However, there is a lack of clear catalytic mechanism to guide the design of efficient catalysts. In this work, the essential role of nanosized catalyst (Ni3Fe/rGO) in activating micro‐sized Mg with ultra‐rapid hydrolysis process is investigated for the first time. Here, an unprecedented content of 0.2 wt% Ni3Fe/rGO added Mg can release 812.4 mL g−1 hydrogen in just 60 s at 30 °C. Notably, an impressive performance with a hydrogen yield of 826.4 mL g−1 at 0 °C in only 30 s is achieved by the Mg‐2 wt% Ni3Fe/rGO, extending the temperature range for practical applications of hydrolysis. Moreover, the four catalysts (Ni3Fe/rGO, Ni3Fe, Ni/rGO, Fe/rGO) are designed to reveal the influence of composition, particle size, and dispersion on catalytic behavior. Theoretical studies corroborate that the addition of Ni3Fe/rGO accelerates the electron transfer and coupling processes and further provides a lower energy barrier diffusion path for hydrogen. Thus, a mechanism concerning the catalyst as migration relay is proposed. This work offers guidelines designing high‐performance catalysts especially for activating the hydrolysis of micro‐sized light weight metals.

As a high-resolution optical imaging technology, Optical Coherence Tomography (OCT) has been widely used in the diagnosis and treatment of cardiovascular diseases. It has played an important role in the detection and identification of atherosclerotic plaques and has significant advantages. In this paper, we realized to extract the optical characteristic parameters of the target sample based on the OCT data by establishing optical transmission models conforming to the OCT principle. The optical phantoms and coronary artery of domestic pig were used as research samples to study the difference between the optical properties of the cardiovascular tissues. It can provide a basic method for further study of optical characteristic parameters of atherosclerotic plaques, and also lay a foundation for realizing the quantitative evaluation of atherosclerotic plaques with multiple optical characteristic parameters in the future.

In this work, Magnesium nanoparticles with Pd decoration, ranging from 40 to 70 nm, were successfully coprecipitated from tetrahydrofuran (THF) solution, assigned as the Mg–Pd nanocomposite. The Mg–Pd nanocomposite exhibits superior hydrogen storage properties. For the hydrogenated Mg–Pd nanocomposite at 150°C, the onset dehydrogenation temperature is significantly reduced to 216.8°C, with a lower apparent activation energy for dehydrogenation of 93.8 kJ/mol H2. High-content γ-MgH2 formed during the hydrogenation process, along with PH0.706, contributes to the enhancing of desorption kinetics. The Mg–Pd nanocomposite can take up 3.0 wt% hydrogen in 2 h at a temperature as low as 50°C. During lower hydrogenation temperatures, Pd can dissociate hydrogen and create a hydrogen diffusion pathway for the Mg nanoparticles, leading to the decrease of the hydrogenation apparent activation energy (44.3 kJ/mol H2). In addition, the Mg–Pd alloy formed during the hydrogenation/dehydrogenation process can play an active role in the reversible metal hydride transformation, destabilizing the MgH2.

Due to high production costs, the popularization and application of microbial flocculants in the field of water treatment have been limited. In this study, the capture of lead ions by the fermentation broth of a novel Paenibacillus sp. strain A9 and cultured with food wastewater was further investigated. The results revealed that the production of MBFA9 could be increased significantly by adding a small amount of carbon and nitrogen to food wastewater. Under the best experimental conditions (pH 8.5, culture temperature 30°C, 150 r/min), adding 1% (m/v) carbon and 0.1% (m/v) nitrogen to 1% (v/v) wastewater resulted in a yield of MBFA9 of 6.29 g/l. At a temperature of 30°C, pH of 5, contact time of 35 min, and FBA9 dosage of 5%, the removal rate and removal capacity of Pb(II) reached the highest values of 95.1% and 317 mg/g, respectively. Field emission scanning electron microscopy analysis indicated that bacterial cells, metabolite small molecule acids, and MBFA9 in FBA9 all contributed to the removal of Pb(II). Fourier-transform infrared spectrometry analysis indicated that functional groups such as –OH, –COOH, –CO, and –NH 2 existed in MBFA9 and on the cell surface. Various mechanisms involved in Pb(II) removal can occur simultaneously, including cell surface adsorption, microcrystallization, and biological flocculation.

A 32-year-old virgin presented with psychosexual dysfunction and a mass in the vulva. The mass arose from the cervix with a thin pedicle and it was 6 × 1.5 cm. The mass protruded outside of the hymen, it had a canal inside and an opening at the distal end, and it had a genital-like appearance. A mucosal fold was found in the tubular lumen. Fibrous smooth muscle was observed in the tubal wall, which was covered by squamous and endometrial glandular epithelium on each side. A cervical giant polyp with a canal inside the polyp might be differentially diagnosed from prolapsed genitals and abnormal sexual development. Polypectomy by mini-hysteroscopy was effective for alleviating psychosexual dysfunction caused by the mass in this patient.

The feasibility of using near-infrared spectroscopy (NIR) to identify wood species was investigated in this study. Case I considers the principal component analysis scores plot of NIR spectra for three wood species. Case II considers whether NIR combined with partial least squares discriminant analyses can be used to identify the three wood species. Three wood species were studied, and each species included five randomly collected wood blocks, 21 samples for each wood block, and 315 total wood samples. In case I, the samples in the PCA analysis were clustered together. In case II, samples in the training set were classified into the correct group, and the accuracy of the test set was up to 90%.

The surface roughness of Chinese fir and Eucalyptus wood samples were measured using the stylus profile method in order to investigate the correlation between near infrared (NIR) spectroscopy and surface roughness. The results showed that the NIR spectra absorption showed differences among samples from different surface roughnesses, and the absorption decreased with the increase of the surface roughness. A strong relationship was found between the surface roughness parameters, i.e., the arithmetical mean deviation of the profile (Ra), the ten-point height of irregularities (Rz), and the maximum height of profile (Ry). Based on the NIR spectra of the Chinese fir wood samples and the mixed wood samples of the two wood species, and the correlation coefficients of these two types of wood samples in a calibration set were 0.77 to 0.83 and 0.67 to 0.74, respectively. A relatively poor correlation was found in the model based on the Eucalyptus samples; however, it was still significant. These results suggested that there was relative information about the surface roughness from the NIR spectra, which further illustrated that the surface roughness may influence the effect of models for wood properties built by NIR data.

Although Mg-based hydrides are extensively considered as a prospective material for solid-state hydrogen storage and clean energy carriers, their high operating temperature and slow kinetics are the main challenges for practical application. Here, a Mg-Ni based hydride, Mg2NiH4 nanoparticles (∼100 nm), with dual modification strategies of nanosizing and alloying is successfully prepared via a gas-solid preparation process. It is demonstrated that Mg2NiH4 nanoparticles form a unique chain-like structure by oriented stacking and exhibit impressive hydrogen storage performance: it starts to release H2 at ∼170 °C and completes below 230 °C with a saturated capacity of 3.32 wt% and desorbs 3.14 wt% H2 within 1800 s at 200 °C. The systematic characterizations of Mg2NiH4 nanoparticles at different states reveal the dehydrogenation behavior and demonstrate the excellent structural and hydrogen storage stabilities during the de/hydrogenated process. This research is believed to provide new insights for optimizing the kinetic performance of metal hydrides and novel perspectives for designing highly active and stable hydrogen storage alloys. [ABSTRACT FROM AUTHOR]