Curing efficiency and ocular hazards of dental photopolymerization sources

The spectral distributions of a range of dental photocuring sources were measured at the exit window and at a distance of 10 cm. The former enabled the evaluation of a newly proposed photocuring efficiency index which correlates well with the depth of cure of the photopolymerized resins, thus providing a basis for the comparison of different photocuring sources. The spectral irradiante of the sources obeyed the inversesquare law, allowing a comparison with the ACGIH threshold limit values. According to these criteria, no ocular hazard is posed to the patient or clinician by u.v.-A or u.v.-B radiation nor to the patient by the visible light when momentarily exposed to the sources. Similarly the ACGIH criterion indicates that the clinician does not risk chorioretinal injury provided the exposure is restricted to less than 140 s in a 3 h period.     

Anti-microbial active composite nanoparticles with magnetic core and photocatalytic shell: TiO2-NiFe2O4 biomaterial system

Reverse micelle and chemical hydrolysis techniques have been successfully combined to synthesize composite nanoparticles consisting of a photocatalytic shell of titania and a magnetic core of nickel ferrite. The nature of titania shell, i.e. anatase or brookite, depends on the TiO₂ and NiFe₂O₄ molar ratio. The work presented here describes the photocatalytic and anti-microbial activity of the composite nanoparticles together with the magnetic characteristics of the nickel ferrite core. The TiO₂-coated NiFe₂O₄ nanoparticles retain the magnetic characteristics of uncoated nanocrystalline nickel ferrites (superparamagnetism; absence of hysteresis, remanence and coercivity at 300 K) encouraging their application as removable anti-microbial photocatalyst nanoparticles that can be extracted from the sprayed surface (human body or environment) after exposure.     

Transport of urea and amino acids through the isolated human placenta

By means of a method of two-way perfusion of the isolated human placenta the transport of urea from the fetal to the maternal placental circulation and the transport of amino acids in the opposite direction were studied. Experiments showed that the method provides for sufficiently complete perfusion of the intervillous space and creates suitable conditions for the study of placental transport. If the amino nitrogen concentrations in the two circulatory systems are equal, its concentration in the fetal circulation rises in the course of the experiment. On the addition of an amino acid to the maternal circulation, this increase develops to a greater degree. The results of these experiments confirm the view that amino acids are secreted by trophoblast cells into the fetal circulation.Laboratory of Biochemistry, Institute of Obstetrics and Gynecology, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR M. A. Petrov-Maslakov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 4, pp. 394–397, April, 1976     

基于骨和无有机成分骨与羟基磷灰石压缩性能实验比较的强度分析

目的分析判定以珊瑚为基体,通过水热交换法制成的羟基磷灰石植入体内后的强度是否可以达到活体骨的水平。方法实验测量羟基磷灰石、含有机成分的骨、无有机成分的骨的压缩极限应力。通过对比羟基磷灰石、骨及无有机成分的骨的压缩强度差别,确定胶原纤维对骨压缩强度的作用,进而应用经验模型预估人造羟基磷灰石在一定空隙度(0.1～0.5)范围变化时的强度。结果羟基磷灰石、骨及无有机成分的压缩强度分别为14.1 GPa、207 GPa和31.7 GPa。结论去除骨中的有机成分后其压缩强度降低约80%。水热交换法制成的羟基磷灰石抗压强度可能高于骨内羟基磷灰石,这种骨替代材料植入体内后,随着骨和纤维组织在内部生长,其强度有可能达到活体骨的水平。     

血糖感应型胰岛素给药智能载体的研究进展

胰岛素控制释放高分子载体系统一直是国内外科技工作者的研究热点 ,迄今已经研究报道了多种具有不同工作原理的血糖感应型胰岛素给药智能载体。本文基于国内外大量研究文献 ,综述了血糖感应型胰岛素控制释放智能化高分子载体的研究进展。     

制备工艺对ATO超细粉体导电性能的影响

采用化学共沉淀法制备锑掺杂二氧化锡（ATO）超细导电粉体,研究了反应温度,滴定终点pH值,掺锑量及锻炼温度对粉体导电性的影响,并对实验结果进行了讨论。     

中药材及饮片质量等级标准研究思路和方法

中药质量评价作为保障中药材及饮片质量安全有效的有力手段,对维护人民群众身心健康、促进中药产业高质量发展具有重要意义。长久以来,中药质量多以法定检验标准为准入门槛进行低限控制,质量等级标准缺乏,致使中药质量仅能满足基本要求,而“优质优价”未能得到充分体现,导致“劣币驱逐良币”,市场公平严重受损,这很大程度影响了中药产业高质量发展。因此,开展中药质量优劣评价研究,构建中药质量等级标准体系对于全面落实“四个最严”要求、促进中医药传承创新发展、规范市场秩序、引导产业健康发展具有深远而重大的意义。对中药材质量评价现状进行概述,针对目前中药材质量评价的瓶颈问题,提出符合中医药特点的质量等级标准研究思路,包括关键质量控制指标确立、综合质量评价方法建立、质量等级标准验证等内容,以期为建立中药质量等级评价体系提供参考,助力中药产业高质量发展。     

Technique for Rapid Hand Transplant Donor Procurement Through the Elbow

Background: Hand and distal forearm allotransplantation has advanced over the last 20 years from experimental to a viable treatment option for bilateral upper extremity amputation. Despite widespread growth of this field, there are few technical reports that elaborate the details of donor arm procurement. This article details a technique for rapid donor procurement through the elbow for mid to distal forearm-level hand allograft procurement. Methods: Nine arm procurements were performed on deceased tissue-only donors provided by the local organ procurement organization, including two bilateral and five unilateral cases. Technique highlights include using a fishmouth incision through the lateral and medical epicondyles, identification of the neurovascular structures, and disarticulating the elbow joint. Results: Procuring through the elbow provides straightforward anatomy, bypasses the need to cut through bone, and allows tissue allotransplantation teams to achieve procurement, flushing, and packaging within 20 minutes. Conclusions: Procurement through the elbow is a simple procedure that streamlines the process for multi-organ donors by minimizing the time needed for hand allograft procurement. Team coordination and surgical rehearsals are essential for successful hand and upper extremity procurement and allotransplantation.     

Life underneath the VCA umbrella: Perspectives from the US Uterus Transplant Consortium

The parallel emergence of uterus transplantation (UTx) and other transplantation innovations including face and hand transplantation led to the categorization of the uterus as a vascular composite allograft (VCA). With >60 transplants and >20 births worldwide, UTx is transitioning rapidly from a research endeavor to an effective treatment option for women with uterine factor infertility. While it originally made sense to group the innovations under one umbrella, it is time to revisit the designation of UTx as a VCA. We describe how UTx needs unique policy, procedural codes, insurance contracts, and educational initiatives. We contend that separating UTx from VCAs may become necessary in the future to avoid hindering the growth and regulation of this field.