Intrinsic Defect Limit to the Growth of Orthorhombic HfO2 and (Hf,Zr)O2 with Strong Ferroelectricity: First-Principles Insights

It is believed that promoting the fraction of ferroelectric orthorhombic phase (o-phase) through O-poor growth conditions can increase the spontaneous polarization of HfO₂ and (Hf,Zr)O₂ thin films. However, the first-principles calculations show that the growth may be limited by the easy formation of point defects in the orthorhombic and tetragonal phases of HfO₂, ZrO₂, and (Hf,Zr)O₂. Their dominant defects, O interstitial (O_i) under O-rich conditions and O vacancy (V_O) under O-poor condition, have low formation energies and quite high density (10¹⁶–10¹⁹ cm⁻³ for 800–1400 K growth temperature). Especially, O_i has negative formation energy in tetragonal HfO₂ under O-rich condition, causing non-stoichiometry and limiting the crystalline-seed formation during o-phase growth. High-density defects can cause disordering of dipole moments and increase leakage current, both diminishing the polarization. These results explain the experimental puzzle that the measured polarization is much lower than the ideal value even in O-poor thin films and highlight that controlling defects is as important as promoting the o-phase fraction for enhancing ferroelectricity. The O-intermediate condition (average of O-rich and O-poor conditions) and low growth temperature are proposed for fabricating HfO₂ and (Hf,Zr)O₂ with fewer defects, lower leakage current, and stronger ferroelectricity, which challenges the belief that O-poor condition is optimal.     

Transglycosylation Activity of Engineered Bifidobacterium Lacto-N-Biosidase Mutants at Donor Subsites for Lacto-N-Tetraose Synthesis

The health benefits of human milk oligosaccharides (HMOs) make them attractive targets as supplements for infant formula milks. However, HMO synthesis is still challenging and only two HMOs have been marketed. Engineering glycoside hydrolases into transglycosylases may provide biocatalytic routes to the synthesis of complex oligosaccharides. Lacto-N-biosidase from Bifidobacterium bifidum (LnbB) is a GH20 enzyme present in the gut microbiota of breast-fed infants that hydrolyzes lacto-N-tetraose (LNT), the core structure of the most abundant type I HMOs. Here we report a mutational study in the donor subsites of the substrate binding cleft with the aim of reducing hydrolytic activity and conferring transglycosylation activity for the synthesis of LNT from p-nitrophenyl β-lacto-N-bioside and lactose. As compared with the wt enzyme with negligible transglycosylation activity, mutants with residual hydrolase activity within 0.05% to 1.6% of the wild-type enzyme result in transglycosylating enzymes with LNT yields in the range of 10–30%. Mutations of Trp394, located in subsite -1 next to the catalytic residues, have a large impact on the transglycosylation/hydrolysis ratio, with W394F being the best mutant as a biocatalyst producing LNT at 32% yield. It is the first reported transglycosylating LnbB enzyme variant, amenable to further engineering for practical enzymatic synthesis of LNT.     

广西2021年早晚籼优质稻主要品种品质测报分析（网络首发、推荐阅读）

通过对广西2021年度推广种植的野香优、广粮香2号、百香、丝香四个主要品种系列的早晚籼优质稻谷品种进行采样，按照《优质稻谷》《中国好粮油 稻谷》《广西好粮油 广西香米》标准中规定质量品质指标进行检测，并依据检测数据对四个主要稻谷品种在不同季节、不同种植区域以及同一种植区域不同种植季节品质变化情况进行对比分析研究，寻找优质稻因品种、产地、种植季节不同对其品质的影响规律，为优质稻谷品种的选育和推广种植工作提供科学依据和数据支持，促进广西优质粮食产业和“广西香米”产业进一步发展。     

Lake charr (Salvelinus namaycush) clotting response may act as a plasma biomarker of sea lamprey (Petromyzon marinus) parasitism: Implications for management and wound assessment

Sea lampreys (Petromyzon marinus) have decimated the Great Lakes fisheries over the past century, and their control is central to protecting native fish populations. Wounding data collected from host fish, including classifying wounds as Type A (penetrating the integument) or Type B (superficial), is an integral part of sea lamprey monitoring efforts and helps inform management decisions; however, wound assessment is subjective and error-prone. This study aimed to determine if protein biomarkers of parasitism could be quantified in host fish plasma to serve as a potential objective aide in current wound assessment practices. Male siscowet lake charr (Salvelinus namaycush) were parasitized in a lab setting for four days, after which the sea lamprey was removed, host blood was collected, and the wound Type recorded. A second blood sample was collected from host fish with Type A wounds 7 months later. The plasma proteome was quantified using iTRAQ, and the relative abundances of 169 proteins were compared between parasitized and non-parasitized control fish. Three functional classes of proteins were modified by sea lamprey parasitism: immune response, lipid transport, and blood coagulation. A major finding was evidence of a concerted anticoagulation response in fish with Type A wounds, including changes in protein components and regulators of fibrin clot formation, some of which did not fully recover within 7 months. A modified clotting assay yielded a smaller thrombin-induced fibrin clot from parasitized fish, supporting the proteomic results. Therefore, measuring blood clottability could improve sea lamprey damage estimates by providing a more objective and quantitative index of parasitism than is offered by wounding data alone.     

Meticulously tailoring phase boundary in KNN-based ceramics to enhance piezoelectricity and temperature stability

Although KNN-based ceramics with high electrical properties are obtained through a variety of strategies, the temperature sensitivity is still one of the key technical bottlenecks hindering practical applications. Here, we use a new strategy, meticulously tailoring phase boundary, to refine the ferroelectric boundary of KNN-based ceramics, leading to high piezoelectricity companied with improving temperature stability. The highest d₃₃ value in this system reaches 501 pC/N with a T_C ∼ 240°C, whereas a large strain of ∼0.134% can be kept with 10% lower deterioration until 100°C. The origin of high piezoelectricity is mainly attributed to the well-preserved multiphase coexistence and the appearance of nanodomains, which greatly facilitate the polarization rotation. Instead of the changed intrinsic thermal insensitivity, the precision phase boundary engineering plays an important role in strengthening the temperature stability of electric-induced strain. This work provides a simple and effective method to obtain both high electrical properties and excellent thermal stability in KNN-based ceramics, which is expected to promote the practical applications in the future.     

对大中型钢结构企业生产管理体系的研究分析

以某大型钢结构制造企业为例,通过对产量分布、质量控制、劳动效率等基本数据的分析,研判外协生产管理体系方面存在的问题,从组织形态、管理模式、职能管理等多个维度提出了可行性建议,可为同类型钢结构制造企业提供经验借鉴。     

Interleukin-1β Modulation of the Mechanobiology of Primary Human Pulmonary Fibroblasts: Potential Implications in Lung Repair

Pro-inflammatory cytokines like interleukin-1β (IL-1β) are upregulated during early responses to tissue damage and are expected to transiently compromise the mechanical microenvironment. Fibroblasts are key regulators of tissue mechanics in the lungs and other organs. However, the effects of IL-1β on fibroblast mechanics and functions remain unclear. Here we treated human pulmonary fibroblasts from control donors with IL-1β and used Atomic Force Microscopy to unveil that IL-1β significantly reduces the stiffness of fibroblasts concomitantly with a downregulation of filamentous actin (F-actin) and alpha-smooth muscle (α-SMA). Likewise, COL1A1 mRNA was reduced, whereas that of collagenases MMP1 and MMP2 were upregulated, favoring a reduction of type-I collagen. These mechanobiology changes were functionally associated with reduced proliferation and enhanced migration upon IL-1β stimulation, which could facilitate lung repair by drawing fibroblasts to sites of tissue damage. Our observations reveal that IL-1β may reduce local tissue rigidity by acting both intracellularly and extracellularly through the downregulation of fibroblast contractility and type I collagen deposition, respectively. These IL-1β-dependent mechanical effects may enhance lung repair further by locally increasing pulmonary tissue compliance to preserve normal lung distension and function. Moreover, our results support that IL-1β provides innate anti-fibrotic protection that may be relevant during the early stages of lung repair.     

基于化学监督的超(超)临界机组关键控制节能指标分析及建议

针对超(超)临界机组参数提高、材质升级,化学技术监督中的监督指标对机组经济性和可靠性影响较大的问题,本文通过机组典型案例分析、技术监督报告、现场实测等,对目前化学监督中影响较大的、关键的技术指标进行了系统性的分析研究。研究结果找出了6项化学监督中超(超)临界机组关键的、影响较大的控制监督指标,且提出了指标控制值和控制方法。这项系统性研究分析方法对指导超(超)临界机组化学监督具有重要的借鉴作用,以控制超(超)临界机组因参数提高和材质升级带来的新问题和新挑战。