The effects of washing a collagen sample prior to TEM examination

Transmission electron microscopy (TEM) is an important analysis technique to visualize (bio)macromolecules and their assemblies, including collagen fibers. Many protocols for TEM sample preparation of collagen involve one or more washing steps to remove excess salts from the dispersion that could hamper analysis when dried on a TEM grid. Such protocols are not standardized and washing times as well as washing solvents vary from procedure to procedure, with each research group typically having their own protocol. Here, we investigate the influence of washing with water, ethanol, but also methanol and 2-propanol, for both mineralized and unmineralized collagen samples via a protocol based on centrifugation. Washing with water maintains the hydrated collagen structure and the characteristic banding pattern can be clearly observed. Conversely, washing with ethanol results in dehydration of the fibrils, often leading to aggregation of the fibers and a less obvious banding pattern, already within 1 min of ethanol exposure. As we show, this process is fully reversible. Similar observations were made for methanol and propanol. Based on these results, a standardized washing protocol for collagenous samples is proposed.     

基质囊泡及其在骨矿化过程中的作用

基质囊泡(Matrix vesicles,MVs)是骨矿物初始形核生长的场所。骨矿化过程中,钙、磷酸根等离子经通道蛋白跨膜运输进入MVs内,当局部浓度达到一定值时,磷酸钙晶体开始沉积。磷酸钙的存在形态包括无定形磷酸钙、磷酸八钙及羟基磷灰石等。MVs可以调节细胞内外基质中的钙和磷酸根离子的稳态及无机磷酸盐/无机焦磷酸盐的比值,提供磷酸钙晶体成核位点,在骨矿化的初始启动过程中发挥重要作用。本文概述了MVs的生物来源、分子组分、提取方法,MVs介导的骨矿化过程,以及近年来利用囊泡作为体外矿化模型模拟MVs矿化过程的研究进展。     

Development of Core-Shell Nanoparticle Drug Delivery Systems Based on Biomimetic Mineralization

Among various drug-delivery systems, core-shell nanoparticles have many advantages. Inspired by nature, biomimetic synthesis has emerged as a new strategy for making core-shell nanoparticles in recent years. Biomimetic mineralization is the process by which living organisms produce minerals based on biomolecule templating that leads to the formation of hierarchically structured organic–inorganic materials. In this minireview, we mainly focus on the synthesis of core-shell nanoparticle drug-delivery systems by biomimetic mineralization. We review various biomimetic mineralization methods for fabricating core-shell nanoparticles including silica-based, calcium-based and other nanoparticles, and their applications in drug delivery. We also summarize strategies for drug loading in the biomolecule-mineralized core-shell NPs. Current challenges and future directions are also discussed.     

铁山岩体北东部铁铜多金属矿成矿规律及成矿预测

铁山岩体北东部分布有多个中、小型矿床，受矿山开采和工作程度影响，多数矿床周边和空白地段未进行评价。为进一步开展矿区深部及其外围找矿勘查工作,扩大资源储量，通过对以往资料的整理分析，结合近些年矿床（点）的勘查资料，从地层、岩浆岩、控矿因素和物探等方面入手，总结成矿规律，并结合物探成果对矿区外围及空白地段进行预测，提出成矿预测靶区，A级3处，B级2处，C级2处。表明研究区内找矿前景较好,值得进一步开展工作。     

贵州三穗地区钒矿地质特征及成矿规律研究

总结贵州省三穗地区钒矿矿区地层、区域构造和区域岩浆岩特征，探讨矿区钒矿成矿规律。研究表明：区内钒矿赋存在陡山沱组白云岩的上部以及老堡组和九门冲组的下部，含矿岩性为黑色炭质黏土岩；成矿来源主要是由于海底裂谷的热气流作用，携带深部钒等多金属元素向陆棚与台地运动、迁移，出现钒的横向分导现象；沉积下来的钒金属又在后期低温热液作用下，以水云母的形式存在，而炭质吸附的部分钒元素进入水云母晶格中，形成钒矿。     

云南省澜沧老厂—孟连茶场地区成矿规律及找矿方向探讨

澜沧老厂—孟连茶场地区位于昌宁—孟连多金属成矿带，研究区域成矿规律对找矿突破有着重要指导意义。在综合分析研究地质背景、化探异常、矿产分布等特征的基础上，将该地区划分为老厂、拉巴、孟连矿（化）集区。老厂铅锌矿床是区域上的典型矿床，其在化探异常、矿床空间分布具有明显的低中高温成矿分带的特征。以该矿床分带特征入手，指出老厂矿（化）集区在地表以低温成矿元素为主，而拉巴、孟连矿（化）集区在化探异常、矿化特征均以低中温成矿元素为主，空间上分带特征不明显。该地区化探异常、矿（化）体分布特征，均表明区域上成矿温度、成矿标高由北至南均具从高到低的降低趋势，认为其可能与燕山期岩浆活动的差异性有关，指出老厂外围、拉巴深部是找矿的有利靶区。     

陕西煤灰纱出现的特征性规律与防治

煤灰纱严重影响纺织产品质量,同时也是难以解决的技术问题。文章分析了煤灰纱出现的特征性规律,试图找到防治煤灰纱的措施,从而找到切实可行的技术解决途径。     

黄沙坪铅锌多金属矿的成矿规律及深部找矿远景

众所周知,矿物质的成分是多种多样的,社会的发展和科学的进步需要运用到多重金属矿物质,在专业人员的勘探与挖掘中,发现了黄沙坪铅锌多金属矿,这个矿区中有丰富的有色金属,这个矿的发掘为研究成矿规律提供了物质基础,同时也为深部找矿提供了可靠的依据。本文主要分析黄沙坪铅锌多金属矿的成矿规律及深部找矿远景。     

Controller design for distributed parameter systems with time delays in the boundary feedbacks via the backstepping method

For a distributed parameter system with an input delay in the boundary, a feedback control law is presented by means of the backstepping method. The square integrability of input signal is verified based on the target system. Then, the boundedness and invertibility of the corresponding backstepping transformation are proved under the regularity of system and the admissibility of feedback operator. Thus, the resulting closed-loop system is shown to be exponentially stable. Finally, as an application, a numerical simulation of a one-dimensional Schrödinger equation with a delay input is carried out, and the simulation results demonstrate the effectiveness of the suggested control law.     

基于地球化学的水热还原矿化稳定砷的技术思路

砷作为有色金属矿物的共伴生元素,在有色金属冶炼过程中以含砷“三废”形式大量产出。由于砷具有强致癌性及毒性,导致砷的安全处置问题严重困扰着有色金属冶炼企业。本文通过阐述含砷废水中砷的两种稳定化工艺的研究进展,对比了现有稳定化工艺的优缺点,结合药剂稳定化和矿物稳定化的优点,借鉴砷元素在地球化学中的成矿规律,提出了硫化沉砷?水热还原矿化稳定砷的技术思路。首先采用硫化法脱除含砷废水中的砷,砷的沉淀率高达99.65%,硫化沉淀物在TCLP毒性检测中砷的浓度达到212.9 mg/L。然后采用As-S系一元水热还原矿化法和As-Fe-S系二元水热还原矿化方法稳定砷,稳定化产物分别为雌黄和雌黄?铁硫系(黄铁矿、硫化亚铁)混合物,在TCLP毒性检测中砷的浸出浓度分别为3.86 mg/L和2.65 mg/L。水热还原矿化工艺实现了含砷废水中砷的脱除及稳定化的目的,为水溶液中砷的脱除和稳定化提供了新的思路。