人工合成锰矿物及微结核(结壳)

介绍了在蒸馏水中０～１０℃条件下，和在含Ｎｉ、Ｃｏ、Ｃｕ和有机质的溶液以及不同底质的合成海水中常温常压条件下合成黑锰矿、钠水锰矿、钡镁锰矿、羟锰矿、菱锰矿以及黑锰矿微结核（直径５．８～４３．５μｍ）、结壳（厚度２０～３３μｍ）的合成实验方法和结果。并得出，控制锰矿物形成的条件是，除必要的物质来源外，起决定作用的是形成环境的酸碱度和氧化还原电位。

沉积作用对印度孟加拉海扇锰的富集和铁锰微结核生长的影响

研究区位于孟加拉海扇,其沉积体南北延伸２８００～３０００ｋｍ,东西延伸８３０～１４３０ｋｍ。每年形成的悬浮沉积物通过河流输入该地区,海湾北部沉积物厚度大约为１６ｋｍ。该研究区内沉积速率变化很明显,海湾东部岩心１１（水深２７１２ｍ）附近的全新世沉积速率（４...

印度洋和太平洋生物生产区锰质微结核的矿物学（二）

采用现代方法研究了印度洋和太平洋近赤道生物生产区沉积物中锰质微结核的矿物成分。显示出微结核中矿物相的相互关系与很多因素有关。查明了印度洋中微结核的含铁率与太平洋相比有增大的趋势。推测六方钠水锰矿是锰太物固相变化的终端产物。为了完成这种转化必须要有近４００万年的时间。

中国海域固体矿产资源分布及其区划——砂矿资源和铁锰(微)结核—结壳

综述和研究了我国海域砂矿资源和(微)结核—结壳的分布及其区划。我国的滨海砂矿广泛分布于渤海、黄海、东海和南海,但各省区的砂矿资源分布不同。近年来在我国海域新发现和圈定了多处砂矿品位异常区和矿物高含量区,可分为3个成矿带和24个成矿远景区,资源储量可观。在黄海、东海仅分布铁锰结核,没有发现铁锰结壳,但它们的金属元素含量低,没有潜在资源意义。南海东北陆坡、中央海盆西部和中部是(微)结核、结壳分布较多的区域。南海东北陆坡、海山及其周缘坡脚处的(微)结核、结壳其稀土元素含量较高,可能具有一定的潜在经济价值,今后调查中应引起重视。

大洋微锰结核中纤锌锰矿的发现及其矿物学特征

报道了发现于东太平洋海盆微锰结核中的一种纤锌锰矿及其矿物学特征。通过采用Ｘ射线衍射、透射电子显微镜及电子探针技术进行的综合研究，证实确为纤锌锰矿。电子探针测得该微锰结核中含Ｚｎ量高达１３．２９％。Ｘ射线及电子衍射特征亦与ＪＣＰＤＳ卡片中的纤锌锰矿数据相吻合。对纤锌锰矿的鉴定定名、成因及其发现的地质意义进行了讨论。

东太平洋中部始新世末期的微锰结核研究

深海钻探573B孔始新世末与渐新世初地层界线处有一层含金属黏土 ,其底部有一微锰结核富集层。研究了这些微锰结核的形态特征、化学成分及形成环境。总体看来始新世末期微锰结核中锰的含量比太平洋CC区的大锰结核、微锰结核含量明显高 ,但铁含量则明显低 ,属亚氧化成岩类型。始新世末期该区丰富的金属元素和微量元素的供给、沉积间断或缓慢的沉积速率等条件利于该时期微锰结核的形成。

3D打印多孔β-磷酸三钙负载聚乳酸-羟基乙酸共聚物抗结核药物缓释微球复合材料:构建及细胞毒性评价

背景:3D打印多孔β-磷酸三钙负载聚乳酸-羟基乙酸共聚物抗结核药物缓释微球复合材料,对细胞尤其是成骨细胞生长和增殖的影响及影响程度尚缺乏可靠的生物医学证据。目的:构建3D打印多孔β-磷酸三钙负载聚乳酸-羟基乙酸共聚物抗结核药物缓释微球材料,检测其细胞毒性。方法:利用3D打印技术制备出20个孔径400μm的多孔β-磷酸三钙材料,随机抽取其中10个负载聚乳酸-羟基乙酸共聚物抗结核药物缓释微球,作为载药支架,其余10个作为非载药支架。将以上两种支架浸提液与成骨细胞共同培养72h,通过倒置相差显微镜观察细胞形态,采用CCK-8法测得成骨细胞A值,计算细胞相对增殖率,评价支架材料的细胞毒性。结果与结论:载药支架大小适度,结构规则,孔隙均匀。培养72 h内,载药支架浸提液中的成骨细胞呈长条形或长梭形,可见少量细胞核固缩,表现出轻微中毒表现,细胞毒性分级为1级,无明显细胞毒性。结果表明3D打印多孔β-磷酸三钙负载聚乳酸-羟基乙酸共聚物抗结核药物缓释微球无明显细胞毒性。

深海沉积物中稀土元素的富集成矿作用

我国虽是稀土大国,但重稀土仍是十分紧缺的关键金属资源。2011年日本学者Kato等在太平洋深海盆地中发现了大规模富含稀土元素的沉积物,引起世界各国高度重视。深海富稀土沉积物广泛分布于海底,其富集稀土元素尤其是相对富集重稀土元素等关键金属,是继大洋结核结壳、洋中脊热液硫化物、天然气水合物之后一种重要的海洋矿产资源。目前太平洋和印度洋中都证实有大面积富稀土沉积物的存在,我国科学家将深海稀土资源分为4个主要成矿远景区,其中太平洋3个,印度洋1个。富稀土沉积物的矿物组分主要包括生物成因磷灰石(鱼牙和鱼骨)、微结核(铁锰氧化物或氢氧化物)、沸石、黏土矿物等,其中生物磷灰石是最重要的稀土载体。稀土元素直接来源于上覆海水和孔隙水,热液和火山活动可能也有贡献。水深、沉积速率和氧化还原环境等是控制深海稀土元素富集的重要因素,强底流、海底火山和热液活动以及气候事件所导致的陆源输入的变化也会对深海稀土富集产生重要影响。深海稀土成矿作用仍然存在一些尚未解决的科学问题,需进一步加强深海富稀土沉积物成因及超常富集机制等的研究,以丰富和完善深海稀土的成矿模型,为我国在深海稀土富集区的勘探研究与实践提供重要借鉴。

α-MnO_2 nanoneedle-based hollow microspheres coated with Pd nanoparticles as a novel catalyst for rechargeable lithium-air batteries

The hollow α-MnO2 nanoneedle-based microspheres coated with Pd nanoparticles were reported as a novel catalyst for rechargeable lithium-air batteries. The hollow microspheres are composed ofα-MnO2 nanoneedles. Pd nanoparticles are deposited on the hollow microspheres through an aqueous-solution reduction of PdCl2 with NaBH4 at room temperature. The results of TEM, XRD, and EDS show that the Pd nanoparticles are coated on the surface ofα-MnO2 nanoneedles uniformly and the mass fraction of Pd in the Pd-coated α-MnO2 catalyst is about 8.88%. Compared with the counterpart of the hollow α-MnO2 catalyst, the hollow Pd-coated α-MnO2 catalyst improves the energy conversion efficiency and the charge-discharge cycling performance of the air electrode. The initial specific discharge capacity of an air electrode composed of Super P carbon and the as-prepared Pd-coatedα-MnO2 catalyst is 1220 mA＆#183;h/g （based on the total electrode mass） at a current density of 0.1 mA/cm2, and the capacity retention rate is about 47.3% after 13 charge-discharge cycles. The results of charge-discharge cycling tests demonstrate that this novel Pd-coatedα-MnO2 catalyst with a hierarchical core-shell structure is a promising catalyst for the lithium-air battery.

Electron Microscopic Studies on the Silver-stained Nucleolar Cycle of Physarum polycephalum

The dynamic changes of nucleolar ultrastructure in the cell cycle of Physarum polycephalum Schw. were studied by an en bloc silver-staining method. The results showed that the nucleolus was large in size and situated in the center of the nucleus in late G(2)-phase, and the fibrillar centers, dense fibrillar components and granular components could be observed in the nucleolus. During prophase, the nucleolus moved towards the periphery of the nucleus and in late prophase disintegrated near the nuclear envelope. in metaphase, the disintegrated nucleolar components were dispersed in masses and located at the periphery of the chromosomal region of the nucleus. No specifically silver-stained area and argentophilic protein sheath were observed on the chromosomes, but there were some big dispersed silver particles within the chromosomes. During telophase the nucleolar components moved towards the two poles along with the chromosomes and co-existed with the decondensing chromatin in daughter nuclei. The nucleolar components then gradually converged with one another and separated from the chromatin. A big nucleolus was formed in the nucleus about 120 min after the completion of mitosis.

Microsatellites underestimate genetic divergence in the Green-backed Tit (Parus monticolus)

Although a growing number of both sequence-based and microsatellite nuclear loci have been used to infer genetic structures, their relative efficiencies remain poorly understood. In our study, we used the Green-backed Tit (Parus monticolus) to explore the resolving ability of these two types of markers. The south-western and central mitochondrial DNA (mtDNA) phylogroups were divergent to some extent in sequence-based nuclear data, while mixed together in microsatellites data. The F ST values among clades were about four times lower in microsatellite loci than those in sequence-based nuclear loci. We are of the opinion that size homoplasy may have contributed to the inability of microsatellites to uncover differentiation. Our results suggest that sequence-based nuclear loci outperformed microsatellite loci in detecting population structures, especially those focused on populations with large effective population sizes. There was no significant correlation between F ST values and allelic size variability, which suggested that the efficiency of microsatellite loci in detecting genetic structure may be independent of their polymorphism. F ST is better than R ST in detecting intraspecific divergence due to the high variance of R ST . In agreement with sequence-based nuclear loci, microsatellite loci did resolve the genetic distinctness of the Taiwan Residents phylogroup. The genetic differentiation between the Taiwan Residents and continental clades may involve allopatric divergence without gene flow.

The structure of the nucleosome core particle of chromatin in chicken erythrocytes visualized by using atomicforce microscopy

The structure of the nuclosome core particle of chromatin in chicken erythrocytes has been examined by usingAFM. The 146 hp of DNA wrapped twice around the corehistone octamer are clearly visualized. Both the ends ofentry/exit of linker DNA are also demonstrated. The dimension of the nucleosome core particles is- 1-4 um inheight and ～13-22 um in width. In addition, superbeads(width of - 48-57 urn, beight of-2-3 nm) are occasionallyrevealed, two turns of DNA around the core particles arealso detected.

脑脊液细胞超微结构的研究

超微水平认识脑脊液(CSF)细胞的结构是光镜下脑脊液细胞形态检查的深入和扩展。由于CSF细胞收集困难,电镜标本制备过程相对复杂,使这一技术受到限制而未能深入开展。近年来我们吸收国内外学者的技术和方法,开展了CSF细胞超微结构的电镜(透射和扫描)的初步研究,现简述如下:

Studies of Microstructure of Kernels of Macadamia integrifolia and Its Hybrids through MRI, X-Ray Tomography and Confocal Microscopy

The aim of this study was to apply the existing techniques that enable examination ofmacadamia kernels to provide a better understanding of physico-chemical properties of kernels during postharvest processing. These techniques, such as X-ray tomography, could be applied for quality monitoring in the macadamia industry. The objectives of this study were to investigate the browning centre symptoms that usually occur in macadamia nuts-in-shell. The applied techniques included confocal microscopy, X-ray tomography and magnetic resonance imaging （MRI）. Five different varieties of macadamia nuts （A38, 246, 816, 842 and Daddow） were selected to include distinct characteristics, such as drop pattern and growing location. Analysis of the microstructure of kernels by confocal microscopy showed the distribution of possible brown pigment compounds as well as the distribution of lipids, carbohydrates and proteins inside macadamia cells. Physical properties data, including shell density and seed to volume ratio, were obtained by X-ray tomography. Magnetic resonance diffusion tensor imaging used in this study showed marked differences in microstructure which indicate that different varieties exhibit different microstructures expressed as fraction ofanisotropy and apparent diffusion coefficient that appear to be related to the occurrence of the brown centre. Hence, the findings of this study have potential to improve the existing postharvest techniques used in the macadamia processing industry. They will be of benefit to the industry in terms of improved quality control and cost reduction.

Preparation, optimization and in vitro evaluation of core-shell paclitaxelloaded nanoparticles composed of MPEG-PLA and PLA

Nanoparticles with typical core-shell structure were prepared with a blend of methoxypoly（ethylene glycol）-poly（lactide） copolymer （MPEG-PLA） and poly （lactic acid） （PLA） along with paclitaxel by the O/W solvent evaporation method. An orthogonal experiment L9（3）3 was applied to get the best preparation conditions. The core-shell paclitaxel-loaded MPEG-PLA/PLA nanoparticles with the highest drug loading efficiency were obtained when amount of MPEG-PLA, time of ultrasonication and volume of deionized water were 300 mg, 10 rain and 30 mL, respectively. The release behavior of paclitaxel from the optimal MPEG-PLA/PLA nanoparticles showed that 22% ofpaclitaxel was released in 14 d. When incubating with human nasopharyngeal carcinoma ceils expressing LMP 1, these optimal nanoparticles showed a little lower tumor growth compared with free paclitaxel.

Sustained release of isoniazid from polylactide microspheres prepared using solid/oil drug loading method for tuberculosis treatment

Polylactide(PLA) microspheres were prepared using the solid-in-oil(S/O) spray-drying method to achieve the sustained release of a hydrophilic drug for the treatment of tuberculosis, via intratracheal instillation. Isoniazid(IN), a low-molecular-weight hydrophilic drug, was used as a model drug. The effects of various sizes of micronized IN powder, different drug/polymer ratios, spray-drying process parameters, and drug-release characteristics were studied to optimize the manufacturing parameters. A high entrapment efficiency(87.3%) was obtained using this method; furthermore, the microspheres were spherical and smooth. They were individually and homogenously distributed, with a mean diameter of 5.6 μm; furthermore, they showed a satisfactory extended sustained-release phase. After administration of the microspheres to rats, pulmonary drug concentrations were maintained at a relatively stable level for up to 4 weeks.

Synthesis and photoluminescent properties of ZnO:Cu/ZnO core/shell nanocrystals

ZnO:Cu/ZnO core/shell nanocrystals are synthesized by a two-step solution-phase process. The morphology, structure and optical properties of the samples are detected by scanning electron microscopy, Raman, absorption and luminescence spectroscopy. The increase of particle size confirms the growth of ZnO shell. The segregation of CuO phase observed in ZnO: Cu core is not detected in ZnO:Cu/ZnO core/shell nanocrystals from Raman spectra. It is suggested that some Cu ions can be segregated from ZnO nanocrystals, and the separated Cu ions can be incorporated inside ZnO shell after the growth of ZnO shell. The visible emission mechanism is discussed in detail, and the photoluminescence analysis indicates that the core/shell structure helps to eliminate the surface-related emission.

One-step preparation of carbon nanotubes with nickel as the core

CNTs with core-shell structure were successfully synthesized by a microwave-assisted polyol method,and magnetic Ni nanoparticles were employed as a catalyst. The preparation method is fast and simple. The structures,morphology and magnetic properties of the as-synthesized samples were investigated using Raman spectrometer,X-ray diffraction (XRD),transmission electron microscopy (TEM),vibrating sample magnetometer (VSM),respectively. The XRD results suggested that Ni particles used as a catalyst in our experiment were nano-sized. In this paper,magnetic Ni nanoparticles were employed as a catalyst,and an electric spark on metal Ni nanoparticles with the microwave eddy current effect could induce CNTs’ formation with the further reaction. The length of hollow carbon nanotubes was micro-sized and the diameters of most of the CNTs were varying from 18 to 20 nm according to the TEM images. Magnetic measurements demonstrated that CNTs with core-shell structure indicated a characteristic ferromagnetic behavior compared with Ni nanoparticles.

Composite core-shell microparticles from microfluidics for synergistic drug delivery

Microparticles have a demonstrated value for drug delivery systems. The attempts to develop this tech- nology focus on the generation of featured microparticles for improving the function of the systems. Here, we present a new type of microparticles with gelatin methacrylate （GelMa） cores and poly（L-lactide-co-glycolide） （PLGA） shells for syn- ergistic and sustained drug delivery applications. The mi- croparticles were fabricated by using GelMa aqueous solu- tion and PLGA oil solution as the raw materials of the mi- croflnidic double emulsion templates, in which hydrophilic and hydrophobic actives, such as doxorubicin hydrochloride （DOX, hydrophilic） and camptothecine （CPT, hydrophobic）, could be loaded respectively. As the inner cores were poly- merized in the microfluidics when the double emulsions were formed, the hydrophilic actives could be trapped in the cores with high efficiency, and the rupture or fusion of the cores could be avoided during the solidification of the micropar- ticle shells with other actives. The size and component of the microparticles can be easily and precisely adjusted by ma- nipulating the flow solutions during the microfluidic emulsi- fication. Because of the solid structure of the resultant mi- croparticles, the encapsulated actives were released from the delivery systems only with the degradation of the biopolymer layers, and thus the burst release of the actives was avoided. These features of the microparticles make them ideal for drug delivery applications.