青霉素V钾胶囊微生物限度检查法的方法学研究

目的:建立青霉素V钾胶囊的微生物限度检查方法。方法:分别采用平皿法、培养基稀释法和薄膜过滤法(每膜100、300、500 ml+青霉素酶)对青霉素V钾胶囊进行微生物限度检查法的研究及控制菌的检查(每膜100、200 ml)。结果 :细菌检查采用薄膜过滤法(每膜500 ml、大于300万u青霉素酶),霉菌和酵母菌采用平皿法,控制菌采用薄膜过滤法(每膜200 ml)时,细菌、霉菌和酵母菌回收率均大于70%。结论:采用薄膜过滤法检查青霉素V钾胶囊中的细菌,平皿法检查霉菌及酵母菌,薄膜过滤法检查控制菌,结果可靠。     

Review of the Applications of Biomedical Compositions Containing Hydroxyapatite and Collagen Modified by Bioactive Components

Regenerative medicine is becoming a rapidly evolving technique in today’s biomedical progress scenario. Scientists around the world suggest the use of naturally synthesized biomaterials to repair and heal damaged cells. Hydroxyapatite (HAp) has the potential to replace drugs in biomedical engineering and regenerative drugs. HAp is easily biodegradable, biocompatible, and correlated with macromolecules, which facilitates their incorporation into inorganic materials. This review article provides extensive knowledge on HAp and collagen-containing compositions modified with drugs, bioactive components, metals, and selected nanoparticles. Such compositions consisting of HAp and collagen modified with various additives are used in a variety of biomedical applications such as bone tissue engineering, vascular transplantation, cartilage, and other implantable biomedical devices.     

Magnetic and Transport Properties of New Dual-Phase High-Entropy Alloy FeRhIrPdPt

High-entropy alloys (HEAs) are broadly explored from the perspective of mechanical, corrosion-resistance, catalytic, structural, superconducting, magnetic properties, and so on. In magnetic HEAs, 3d transition metals or rare-earth elements are well-studied compositional elements. We researched a magnetic HEA containing Fe combined with 4d and 5d transition metals, which has not been well investigated, and found a new dual-phase face-centered-cubic (fcc) HEA FeRhIrPdPt. The structural, magnetic, and transport properties were evaluated by assuming that FeRhIrPdPt is a mixture of FeRh₄, FeIr₄, FePd₄, and FePt₄, all with the fcc structure. The dual-phase is composed of a Rh- and Ir-rich main phase and a Pd- and Pt-rich minor one. FeRh₄ and FeIr₄ show spin freezings at low temperatures, while FePd₄ and FePt₄ are ferromagnetic. Two magnetic features can characterize FeRhIrPdPt. One is the canonical spin-glass transition at 90 K, and the other is a ferromagnetic correlation that appears below 300 K. The main and minor phases were responsible for the spin-glass transition and the ferromagnetic correlation below 300 K, respectively.     

Prospects for Electrical Performance Tuning in Ca3Co4O9 Materials by Metallic Fe and Ni Particles Additions

This work further explores the possibilities for designing the high-temperature electrical performance of the thermoelectric Ca₃Co₄O₉ phase, by a composite approach involving separate metallic iron and nickel particles additions, and by employing two different sintering schemes, capable to promote the controlled interactions between the components, encouraged by our recent promising results obtained for similar cobalt additions. Iron and nickel were chosen because of their similarities with cobalt. The maximum power factor value of around 200 μWm⁻¹K⁻² at 925 K was achieved for the composite with the nominal nickel content of 3% vol., processed via the two-step sintering cycle, which provides the highest densification from this work. The effectiveness of the proposed approach was shown to be strongly dependent on the processing conditions and added amounts of metallic particles. Although the conventional one-step approach results in Fe- and Ni-containing composites with the major content of the thermoelectric Ca₃Co₄O₉ phase, their electrical performance was found to be significantly lower than for the Co-containing analogue, due to the presence of less-conducting phases and excessive porosity. In contrast, the relatively high performance of the composite with a nominal nickel content of 3% vol. processed via a two-step approach is related to the specific microstructural features from this sample, including minimal porosity and the presence of the Ca₂Co₂O₅ phase, which partially compensate the complete decomposition of the Ca₃Co₄O₉ matrix. The obtained results demonstrate different pathways to tailor the phase composition of Ca₃Co₄O₉-based materials, with a corresponding impact on the thermoelectric performance, and highlight the necessity of more controllable approaches for the phase composition tuning, including lower amounts and different morphologies of the dispersed metallic phases.     

How Good Are the Performances of Graphene and Boron Nitride Against the Wear of Copper?

We investigate the copper-wear-protective effects of graphene and boron nitride in single asperity sliding contact with a stiff diamond-coated atomic force microscopy (AFM)-tip. We find that both graphene and boron nitride retard the onset of wear of copper. The retardment of wear is larger with boron nitride than with graphene, which we explain based on their respective out-of-plane stiffnesses. The wear protective effect of boron nitride comes, however, at a price. The out-of-plane stiffness of two-dimensional materials also determines their friction coefficient in a wear-less friction regime. In this regime, a higher out-of-plane stiffness results in larger friction forces.     

Orthotopic liver transplantation in a patient with combined hemophilia A and B

A 38-year-old man with severe factor IX and mild factor VIII deficiencies complicated by cirrhosis secondary to chronic non-A non-B hepatitis underwent orthotopic liver transplantation as treatment for both the cirrhosis and his congenital coagulopathy. Intraoperative hemostasis was obtained with factor VII-depleted prothrombin complex concentrate and fresh frozen plasma. Factor VIII and factor IX levels were assayed frequently in the perioperative period, and both returned to normal within 24 hr and remained normal postoperatively. Liver transplantation can be considered as definitive therapy for hemophilia A and/or B with transfusion-related liver disease.     

电子线路板粉末浸出液重金属含量分析及其饲养斑马鱼前后鱼体内镍铬水平的变化

目的通过分析电子线路板粉末中主要重金属成分的含量及其浸出液中重金属含量,分析其中可溶性重金属盐类所占的比重,同时通过动物实验初步探讨该废弃物溶出液饲养斑马鱼后镍镉在斑马鱼体内变化的情况。方法通过原子吸收分光光度法分析并对比电子线路板粉末和浸出液中铜、铅、锌、镉、镍、铬、铁、锰的含量,初步分析该粉末中重金属的溶出情况及对水体可能的影响。通过对不同剂量浸出液饲养的斑马鱼体内镍铬含量的分析,探讨其在斑马鱼体内变化的情况。结果电子线路板粉末中含量最高的前3位金属分别是铜、铅和铁,分别达64.1、55.6和25.8 mg/kg;金属铬未被检出。浸出液中含量最高的前3位金属分别是铜、锰和镉,其含量分别达1.440、0.322和0.088 mg/L。在实验室饲养斑马鱼中,虽然对照组、低剂量组和中剂量组检测结果有一些不同,但其差异无统计学意义。结论电子线路板拆解废弃物中铜、锰、镉溶出量较高,应在现场监测中重点关注。用一定浓度的浸出液饲养斑马鱼体,其体内的镍铬水平基本无变化。     

基于中国居民疾病发病和死亡情况的环境重金属污染健康风险评估标准探讨

重金属污染日趋严峻,严重影响了人们的生活质量,而健康风险评估可有效地应用于环境管理决策.基于健康风险评估标准制定的原则,通过结合中国居民慢性病的患病率和死亡率现状,参照不同国家的健康风险评估标准,对适合中国人群的环境重金属污染健康风险评估标准进行探讨.