Kiwi Omnicup versus Malmstrom metal cup in vacuum assisted delivery: a randomized comparative trial

AIM: To compare the success, clinical outcomes, and maternal and neonatal complications between the Kiwi Omnicup and the Malmstrom metal cup in vacuum assisted delivery. METHODS: This was a prospective randomized comparative trial. Women who required vacuum assisted vaginal delivery were randomized into the Kiwi Omnicup (KO) group and the Malmstrom metal cup (MM) group. The vacuum assisted deliveries were conducted according to hospital protocol. Details of the procedure and delivery outcomes including success and complications were analyzed. RESULTS: One hundred and sixty-four women were recruited - 85 were assigned to vacuum assisted delivery using the KO and 79 the MM. One hundred percent delivery success was achieved with no significant differences between the two instruments in terms of maternal morbidity (P = 0.66). Six women in the MM group sustained post delivery complications in comparison to five in the KO group. Three babies were diagnosed with birth asphyxia in each group. More babies in the MM group were admitted to the Neonatal Intensive Care Unit (NICU) (10 babies versus 5 babies) and suffered complications (14 versus 12 babies), compared to the KO group, although the difference was not statistically significant. There were no intrapartum or neonatal deaths and of those admitted to the NICU, all were discharged within a week without any serious consequences. CONCLUSION: Kiwi Omnicup is an effective alternative to the currently available Malmstrom metal cup for vacuum assisted delivery with no increase in maternal or neonatal morbidity or mortality.     

Contact-Free Support Structures for the Direct Metal Laser Melting Process

Although Direct Metal Laser Melting (DMLM), a powder bed fusion (PBF) Additive Manufacturing (AM) for metallic materials, provides many advantages over conventional manufacturing such as almost unlimited design freedom, one of its main limitations is the need for support structures beneath overhang surfaces. Support structures are generally in contact with overhang surfaces to physically prop them up; therefore, they need to be removed after manufacturing due to not constituting a part of the main component design. The removal of supports is a process sequence adding extra time and cost to the overall manufacturing process and could result in damaging the main component. In this study, to examine the feasibility of contact-free supports for overhang surfaces in the DMLM process, coupons with these novel types of supports were prepared from CoCrMo alloy powder. This study aims to understand the effect of two parameters: the gap distance between supports and overhang surfaces and the inclination angle of overhang surfaces, on the surface topography and microstructural properties of these surfaces. Visual inspection, roughness measurements, and optical microscopy were utilized as characterization methods The roughness parameters (Ra, Rq, and Rz) were obtained using the focus variation method, and optical microscope analysis was performed on the cross-sections of the overhang surfaces to investigate the sub-surface microstructure and surface topology. Results showed that contact-free supports have a positive effect on decreasing surface roughness at all build angles when the gap distance is correctly set to avoid sintering of the powder in between the overhang and supports or to avoid too large gaps eliminating the desired effect of the higher thermal conductivity.     

Pore-Forming Cardiotoxin VVA2 (Volvatoxin A2) Variant I82E/L86K Is an Atypical Duplex-Specific Nuclease

VVA2 (volvatoxin A chain 2) is a cardiotoxic protein purified from Volvariella volvacea. Its biological activities include hemolysis, writhing reaction, neurotoxicity, and ventricular systolic arresting activity. The cytotoxicity of VVA2 was mainly considered due to its pore-forming activity. Here we report a novel biological activity of its variants VVA2 I82E/K86K as a duplex-specific nuclease. Recombinant VVA2 variant I82E/L86K (Re-VVA2 I82E/L86K), deprived of the oligomerization property, shows increased nuclease activity compared to VVA2. Re-VVA2 I82E/L86K converts supercoiled DNA (Replicative form I, RF I) into nicked form (RF II) and linear form (RF III) in the presence of Mg²⁺ or Mn²⁺. Besides plasmid DNA, it also exhibits nuclease activity on E. coli genomic DNA rather than ssDNA or RNA. Re-VVA2 I82E/L86K preferentially cleaves dG-dC-rich dsDNA regions and shows the best performance at pH 6–9 and 55 °C. Our structure–function study has revealed amino acid E111 may take an active part in nuclease activity through interacting with metal ions. Based on the sequences of its cleavage sites, a “double-hit” mechanism was thereby proposed. Given that Re-VVA2 I82E/L86K did not exhibit the conserved nuclease structure and sequence, it is considered an atypical duplex-specific nuclease.     

Photoreduction of Copper Ions Using Silica–Surfactant Hybrid and Titanium (IV) Oxide under Sulfuric Acid Conditions

Photoreduction of Cu²⁺ ions to Cu metal by titanium(IV) oxide (TiO₂) was conducted in the presence of a silica–surfactant hybrid under sulfuric acid conditions. After irradiation, a dark-red color, reflections due to Cu metal in the X-ray diffraction pattern, and peaks due to Cu 2p_1/2 and 2p_3/2 in the X-ray photoelectron spectrum indicated the precipitation of Cu metal in the product. In addition, an increase in the Brunauer–Emmett–Teller specific surface area from 36 and 45 m²/g for the silica–surfactant and TiO₂, respectively, to 591 m²/g for the product, and a decrease in the intensity of the C-H stretching band in the Fourier–transform infra-red spectra implied the removal of surfactant during the reaction. These characteristics were never observed when TiO₂ was used solely. Therefore, this study indicated that the photoreduction of Cu²⁺ ions to Cu metal by TiO₂ was facilitated under the sulfuric acid medium, where the surfactants extracted from silica–surfactant hybrids by protons in the acidic condition were successfully photo-oxidized by TiO₂. Thus, this study presents a new application of the conversion of a silica–surfactant hybrid into mesoporous silicas.     

Permeability and Load Capacity of Iron Porous Bearings with the Addition of Hexagonal Boron Nitride

Due to their properties, porous sliding bearings are considered to be maintenance-free, which means that no lubrication is required during operation. Their design enables operation at low rotational speeds with high load. Another effect of this bearing design is the lubrication continuity in the tribological pair. In this study, the selected tribological properties (such as load capacity and permeability) of new-generation iron porous bearings with boron nitride powder were experimentally investigated. Tests were carried out under various conditions, using unique test apparatus. The addition of 3% (weight) of hexagonal boron nitride (hBN) significantly increased the load capacity of tested porous bearings in comparison to the same standard bearings containing 2.5% copper. The obtained p_gr·v rating reached almost 7 MPa, which is a value almost three times higher than the requirements for this type of bearing. It is worth emphasizing that such a result was obtained despite a noticeable deterioration in the air and oil permeability of the bearing.     

铁调素在小鼠脑内的表达及其对膜铁转运蛋白1和二价金属离子转运体1表达的影响

目的 探讨铁调素(hepcidin)在小鼠脑内的表达及其对膜铁转运蛋白1(ferroportir 1)和二价金属离子转运体1(DMT1)表达的调节作用.方法 应用RT-PCR技术检测铁调素在正常小鼠各脑区的表达分布,并观察了脑室内注射铁调素对DMT1、膜铁转运蛋白1表达的影响 结果 铁调素在小鼠脑内有广泛表达,且不同脑区表达程度不同,脉络丛部分表达较高.结论 侧脑室内注射铁调素后,能够显著影响DMT1、膜铁转运蛋白1表达,且具有明显的区域特异性.     

金属雕塑的历史沿革

人类进入文明社会之际 ,硬度远远高于陶器的青铜器 ,有力地促进了人类的文明进程。铁器的出现和广泛使用 ,极大地促进了社会生产力的发展 ,导致封建社会的建立和奴隶制社会的崩溃。大工业革命的历史巨轮隆隆行驶在用新的金属材质“钢”制成的轨迹上 ,崭新的历史纪元伴随日新月异的现代科学技术的急速发展 ,不断为人类拓展着新的生活空间 ,金属在人类历史上所起的重要作用 ,超越了艺术的领域 ,甚至成为人类社会文明进步的一种标识。     

Static and Fatigue Behaviour of Double-Lap Adhesive Joints and Notched Metal Samples Reinforced by Composite Overlays

The use of composite overlays to increase the fatigue life of notched steel samples is discussed in this paper. For such purposes, in the first set of studies, static and fatigue tests as well as the detailed analytical and numerical analyses for samples with double-lap joints were performed. Based on such studies, the shapes of the composite overlays were set. For a better understanding of the failure forms of the investigated adhesive joints, the experimental studies were monitored with the use of digital image correlation. In the second set of experimental studies, the static and fatigue tensile tests were performed for steel samples with a rectangular opening with rounded corners reinforced by composite overlays. The different shapes (square 45 × 45 mm and long stripes 180 × 15 mm) and composite materials (GFRP and CFRP) were used as overlays. The obtained improvement of fatigue life was in the range of 180–270% in the case of the rectangular overlays and 710% in the case of application of the overlays in the form of the long stripes. This was also confirmed by numerical analyses in which a reduction in the stress concentration factor from 2.508 (bare sample) through 2.014–2.183 (square 45 × 45 mm overlays) to 1.366 (overlays in the form of long stripes 180 × 15 mm) was observed.     

中国农村饮用水与环境卫生现状调查

  目的  分析山东省不同农村地区的环境卫生与疾病的现状及区域变化特点,为制定相应的干预和控制措施提供依据。  方法  2015 — 2017年,结合山东省地理位置,按东部、中部、西部进行分层,共选取25个县（市）,采用抽签的方法在每县随机抽取20个自然村,每自然村随机抽取5户家庭,共500个村2 500户,采用统一调查表,通过查阅资料、现场调查、访谈、土壤样品采集、实验室检测等方式收集相关信息。  结果  调查县无害化卫生厕所普及率为53.34 %,东、中、西部的差异有统计学意义（P < 0.05）,无害化卫生厕所普及率与区域的人均年纯收入呈正相关（r = 0.997,P < 0.05）。500个村粗死亡率为563/10万,心脏病、恶性肿瘤、脑血管病是死亡的主要原因。垃圾、污水处理厂人口覆盖率平均为58.50 %和40.80 %,东、中、西部差异有统计学意义（P < 0.05）。农村土壤中蛔虫卵检出率为17.20 %,东、中、西部差异无统计学意义（P = 0.31）,活蛔虫卵检出率为5.20 %,东、中、西部差异有统计学意义（P < 0.05）;东、中、西部的蛔虫卵检出率与人均年纯收入呈显著负相关（r = – 0.998,P = 0.04）。土壤重金属合格率为87.40 %,东、中、西部差异有统计学意义（P < 0.05）,土壤中镉合格率为89.00 %,东、中、西部差异有统计学意义（P < 0.05）。  结论  山东省不同地域的农村环境因素和疾病间明显相关,西部地区土壤中活蛔虫卵检出率偏高;东部地区土壤污染的主要因素是镉;应针对不同地域特点采取相应的干预和控制措施。     

Regression of Myocardial Dysfunction After Switching from Desferrioxamine to Deferiprone Therapy in β-Thalassemia Major Patients

This study tries to compare the cardioprotective effects of the desferrioxamine (DFO) and deferiprone (L1) therapies on thalassemia major patients. We enrolled nine patients with thalassemia major complicated by some degree of myocardial dysfunction. These patients, recipients of >10 years of DFO injection therapy, were switched from DFO to L1. Echocardiographic measures of left ventricular systolic, diastolic and global functions, were assessed regularly every 6 months. Mean values of each parameter for the DFO and L1 treatment periods were compared using paired t-test and Wilcoxon signed-rank test. Global cardiac function improved significantly. Myocardial dysfunction in patients with thalassemia major can be reversed by regular use of the oral iron chelator L1.