Special features of spatial redistribution of selenium atoms implanted in silicon

The spatial distribution of selenium atoms implanted in silicon was studied by secondary-ion mass spectrometry after annealing in the temperature range of 600–1200°C. For implantation doses exceeding the amorphization dose for silicon, formation of a peak of selenium concentration was detected beyond the mean projected range of selenium ions. The spatial position of the peak correlates well with the spatial position of the plane in which the calculated value of the specific energy losses of selenium ions in elastic collisions (according to the TRIM code) corresponds to the critical value for amorphization of silicon. Accumulation of impurities at the peak occurs at temperatures of 700°C and higher after recrystallization of the amorphized layer. Redistribution of selenium atoms to deeper layers of the sample due to diffusion is controlled by the temperature dependence of the solubility of selenium in silicon.     

Special features of photoluminescence in silicon-on-insulator structures implanted with hydrogen ions

The special features of photoluminescence spectra of silicon-on-insulator structures implanted with hydrogen ions are studied. An increase in the photoluminescence intensity with increasing hydrostatic pressure P during annealing and the formation of narrow periodic photoluminescence peaks in the spectral range from ～500 to 700 nm are revealed for the structures annealed at P > 6 kbar. It is shown that the fine structure of the photoluminescence spectra correlates with the slowing-down of hydrogen effusion from the implanted samples and with the suppression of the formation of hydrogen microbubbles in the surface layer. These processes promote the formation of an optical resonator, with the mirrors formed by the “silicon-on-insulator-air” and “silicon-on-insulator-SiO₂” interfaces and with the optically active layer formed by hydrogen ion implantation and subsequent annealing.     

骨巨细胞瘤组织及原代培养细胞超微形态学观察

目的：通过骨巨细胞瘤组织及原代培养细胞与其超微形态学观察,了解该肿瘤的体外生长行为、特点及细胞细胞类型进一步探讨其组织来源。方法：对收集到的８例切除或刮除骨巨细胞瘤标本进行了原代培养。所有标本术前均未接受放疗或化疗;术后经病理证实,实体瘤及培养细胞均按常规方法制备标本,透射电镜观察。结果：本组原代培养成功６例,培养细胞从形态上主要可见到多核巨细胞、梭形的单个核细胞、单相核吞噬细胞样细胞。电镜观察发现无论是组织样本还是细胞样本,单个核细胞与多核巨细胞的形态相似,二者的超微结构形态未见明显差异;培养细胞与组织样本中所见的瘤细胞形态未见差别,而瘤细胞形态与正常间质纤维母细胞完全不同,说明培养细胞主要为肿瘤性细胞。结论：原代培养存活期较长的细胞主要为梭形细胞,这些细胞与实体瘤组织中的梭形细胞形态一致,支持梭形细胞为骨巨     

An EDTA-KOH method to expose bone cells for scanning electron microscopy.

To observe bone cells by scanning electron microscopy (SEM), the mouse parietal bones were processed by decalcification with EDTA and digestion of collagen fibers with KOH to remove the bone matrix, in addition to the conventional preparation for SEM. The critical-point-dried specimens were split into two membranous pieces along the gaps formed by removing the bone matrix. By this method, osteoclasts showing full three-dimensional images of ruffled borders, osteoblasts showing special structures on the surfaces facing the bone matrix, and osteocytes extending many slender processes were clearly demonstrated in SEM. This new method may provide new viewpoints in bone cell biology.     

Morphological granulometric features of nucleus in automatic bone marrow white blood cell classification.

The proportion of counts of different types of white blood cells in the bone marrow, called differential counts, provides invaluable information to doctors for diagnosis. Due to the tedious nature of the differential white blood cell counting process, an automatic system is preferable. In this paper, we investigate whether information about the nucleus alone is adequate to classify white blood cells. This is important because segmentation of nucleus is much easier than the segmentation of the entire cell, especially in the bone marrow where the white blood cell density is very high. In the experiments, a set of manually segmented images of the nucleus are used to decouple segmentation errors. We analyze a set of white-blood-cell-nucleus-based features using mathematical morphology. Fivefold cross validation is used in the experiments in which Bayes' classifiers and artificial neural networks are applied as classifiers. The classification performances are evaluated by two evaluation measures: traditional and classwise classification rates. Furthermore, we compare our results with other classifiers and previously proposed nucleus-based features. The results show that the features using nucleus alone can be utilized to achieve a classification rate of 77% on the test sets. Moreover, the classification performance is better in the classwise sense when the a priori information is suppressed in both the classifiers.     

大鼠骨髓源性内皮祖细胞的体外分离、培养及鉴定

目的：体外分离、扩增培养大鼠骨髓源性内皮祖细胞,并进行生物学特性鉴定,为后续实验研究提供材料准备。方法：采用密度梯度离心法和差速贴壁法分离获得单个核细胞,置于特殊培养基EGM -2MV进行扩增培养,对细胞行免疫荧光法检测CD34、CD133、VEGFR2的表达情况,摄取DiI-ac-LDL、结合FITC -UEA-1双染色鉴定及细胞迁移实验。结果：刚分离的单个核细胞小而圆,诱导培养4d左右细胞开始变大,部分呈梭形或多角形,2周左右呈条索状排列;细胞免疫荧光法鉴定CD34、CD133、VEGFR2为阳性,细胞既能吞噬DiI -ac -LDL又能与FITC-UEA-1结合;细胞迁移实验可见每个视野迁移细胞数为（16．6±1．05）个。结论：通过密度梯度离心法和差速贴壁法能成功获取单个核细胞,在特定培养基EGM -2MV中培养后可分化成为内皮祖细胞,为后续实验提供了细胞来源。     

Starvation induces the formation of giant mitochondria in gastric parietal cells of guinea pigs

Mitochondria occasionally increase in size in response to metabolic injury. Numerous studies have reported giant mitochondria in patients with various diseases and animals with metabolic injuries, but there are few reports on giant mitochondria in normal cells under physiological conditions. Here, we report giant mitochondria in normal gastric parietal cells. Stomachs of guinea pigs fed freely, fasted or fasted and then injected with histamine were processed for electron microscopy. Giant mitochondria >2 microm in the diameter of their major axis were observed in resting-type parietal cells in the gastric glands of animals fasted for 60-72 h, whereas acid-secreting-type parietal cells found in those fed ad libitum did not contain giant mitochondria. Giant mitochondria showed unusual structures, especially in their cristae: they contained closely packed, tubular and concentric cristae as well as amorphous and pleomorphic inclusion bodies in their matrix. We observed giant mitochondria consisting of several segments, suggesting the fusion of several normal-sized mitochondria. Histamine injection decreased in a frequency of giant mitochondria in accordance with a decrease in a frequency of resting-type parietal cells. This is the first report of giant mitochondria in gastric parietal cells under physiological or near physiological conditions. Gastric parietal cells might be a good model for examining mitochondrial fusion and fission in a physiological state accompanied by the morphological change of the cells in the membrane system from an acid-secreting to resting type.     

SPK1基因转染对大鼠骨髓间充质干细胞的影响

籽晶是影响K(DxH1-x)2PO4(DKDP)晶体生长和光损伤阈值的一个重要因素.该文采用传统降温法,分别利用Z片和[101]晶片作为籽晶,从氘化程度为85%的溶液生长了DKDP晶体,并加工部分Ⅱ类3倍频晶片样品,进行了3倍频光损伤阈值测试和损伤形貌观测的实验.结果表明,相较于Z片籽晶,[101]晶片作为籽晶所得晶体样品光损伤阈值提高1.54倍且能有效缩短晶体的生长周期.     

Communication scheduling to minimize thermal effects of implanted biosensor networks in homogeneous tissue

A network of biosensors can be implanted in a human body for health monitoring, diagnostics, or as a prosthetic device. Biosensors can be organized into clusters where most of the communication takes place within the clusters, and long range transmissions to the base station are performed by the cluster leader to reduce the energy cost. In some applications, the tissues are sensitive to temperature increase and may be damaged by the heat resulting from normal operations and the recharging of sensor nodes. Our work is the first to consider rotating the cluster leadership to minimize the heating effects on human tissues. We explore the factors that lead to temperature increase, and the process for calculating the specific absorption rate (SAR) and temperature increase of implanted biosensors by using the finite-difference time-domain (FDTD) method. We improve performance by rotating the cluster leader based on the leadership history and the sensor locations. We propose a simplified scheme, temperature increase potential, to efficiently predict the temperature increase in tissues surrounding implanted sensors. Finally, a genetic algorithm is proposed to exploit the search for an optimal temperature increase sequence.     

Understanding of the annealing temperature impact on ion implanted bifacial n‐type solar cells to reach 20.3% efficiency

Ion implantation has the advantage of being a unidirectional doping technique. Unlike gaseous diffusion, this characteristic highlights strong possibilities to simplify solar cell process flows. The use of ion implantation doping for n‐type PERT bifacial solar cells is a promising process, but mainly if it goes with a unique co‐annealing step to activate both dopants and to grow a SiO₂ passivation layer. To develop this process and our SONIA cells, we studied the impact of the annealing temperature and that of the passivation layers on the electrical quality of the implanted B‐emitter and P‐BSF. A high annealing temperature (above 1000 °C) was necessary to fully activate the boron atoms and to anneal the implantation damages. Low J_0BSF (BSF contribution to the saturation current density) of 180 fA/cm² was reached at this high temperature with the best SiO₂ passivation layer. An average efficiency of 19.7% was reached using this simplified process flow (“co‐anneal process”) on large area (239 cm²) Cz solar cells. The efficiency was limited by a low FF, probably due to contaminations by metallization pastes. Improved performances were achieved in the case of a “separated anneals” process where the P‐BSF is activated at a lower temperature range. An average efficiency of 20.2% was obtained in this case, with a 20.3% certified cell. Copyright © 2014 John Wiley & Sons, Ltd.     

Effects of enamel matrix derivative on mineralized tissue formation during bone wound healing in rat parietal bone defects

Enamel matrix derivative (EMD: Emdogain) has been reported to stimulate the biosynthesis and regeneration of trabecular bone. To address whether the biological action of EMD is dependent on the local environment of osseous tissue, circular perforations were made in parietal bones and immediately filled with either EMD or its carrier, propylene glycol alginate (PGA), as control. On post-operative days 4-60, the dissected bones were examined by various histological techniques. New bone matrix, which was immunoreactive for bone sialoprotein (BSP), was formed from the periosteum at the peripheral area of perforations. Different from the findings reported in injured long bones, mineralized tissue was produced in the regenerating connective tissue within bone defects. This mineralized tissue was hardly immunostained for BSP, contained few collagen fibres, and lacked osteocytic lacunae and layers of osteoblasts and osteoid. Energy-dispersive X-ray analysis showed that Ca and P weight % and Ca/P molar ratio of this mineralized tissue were similar to or slightly higher than those in the pre-existing parietal bones. In addition, most multinucleated cells located in mineralized tissue lacked a ruffled border structure and showed weak immunoreaction for the lysosomal cysteine proteinase, cathepsin K, whereas those located in the bone matrix exhibited ruffled borders and strong cathepsin K expression. However, multinucleated cells located in both tissues were strongly stained for tartrate-resistant acid phosphatase. The volume fraction of such mineralized tissue appeared to be higher in EMD-applied bones than in PGA-applied controls. The mineralized tissue-forming stromal cells within bone defects appeared to show greater accumulation in EMD-applied bones than in PGA-applied controls. Our results suggest that the bioactive effects of EMD on bone wound healing and mineralized tissue formation depend, at least in part, on the local osseous environment where EMD has been applied.     

Enhancement of low-contrast curvilinear features in imagery.

A new method is described for enhancing low-contrast curvilinear features in imagery that combines directional filtering with Fischler, Tenenbaum and Wolf's F* algorithm for computing minimum cost paths. The method exploits a phenomenon called "the stability of lines over angle." The idea is that when a directionally filtered image contains a line plus noise, minimum cost paths tend to be aligned in the direction of the line with random jumps between parallel paths. When the input image contains noise only, the direction of minimum cost paths resemble random walks with drift. As the direction of the filter changes, minimum cost paths that follow true features persist and are more stable over angle than those that follow noise. Adding them up in an accumulator array over angle produces a larger number of votes along signal paths than along noise paths. This provides a means for enhancing trajectories of low-contrast features. Several examples illustrate the enhancement of forest trails in USGS aerial imagery, linear features on Mars, and roads in synthetic aperture radar imagery.     

Analysis of specific growth features of zinc oxide nanocrystals from aqueous solutions to fabricate thin-film solar cells

Specific features of the chemical deposition of zinc oxide nanocrystals from aqueous solutions have been studied. A correlation between geometric parameters of zinc oxide nanocrystals and technological modes of their chemical deposition from aqueous solutions has been found. The efficiency of using an array of zinc oxide nanocrystals in SnO₂:F/ZnO/In₂S₃/CuSCN thin-film heterostructured solar cells is demonstrated.     

Effect of carcinogenic substances on bone marrow cells in CBA mice

The effect of some carcinogenic and non-carcinogenic agents on the content of CFUs and frequency of micronuclei (Howell-Jolly corps) in polychromatic erythrocytes of bone marrow cells was studied in CBA mice. Benzene administration decreased the content of CFUs in bone marrow cells, but this effect is considered to be rather a sign of its hematotropic than carcinogenic action. Changes in the CFUs amount induced by chrysotile-asbestos and quartz DQ-12 action were insignificant. All investigated carcinogenic agents (benz(a)pyrene, asbestos and benzene) significantly increased the number of micronuclei in polychromatic erythrocytes of bone marrow in mice.     

Appearance of the reticular cells which trap antigens in the rat lymph node in postnatal development.

The cells binding and retaining immune complexes on their cell surface existed in rat lymph nodes with no germinal centers. This study attempted to clarify the relationship between the two types of cells, reticular cells and follicular dendritic cells (FDCs), in the rat lymph node at early stages of postnatal development by immuno-electron microscopy on anti-horseradish peroxidase (HRP) and HRP injected rat. On the 19th and 23rd day after birth, germinal centers were not yet constructed nor were typical FDCs visible. However, immune complex binding cells were observed on the 23rd day, and not on the 19th. HRP reactive materials (immune complexes) were localized between lymphocytes and large lucent cells, making meshworks. They were revealed by electron microscopy on the cell surface which invaginated into the cytoplasm. The HRP reactive cells extended their cytoplasmic processes and formed a connection by their processes. They were reticular cells which enclosed reticular fibers by their cytoplasmic processes or contacted with reticular fibers closely. The reticular cells may be precursors of the FDCs.     

Prediction of biomechanical properties of trabecular bone in MR images with geometric features and support vector regression

Whole knee joint MR image datasets were used to compare the performance of geometric trabecular bone features and advanced machine learning techniques in predicting biomechanical strength properties measured on the corresponding ex vivo specimens. Changes of trabecular bone structure throughout the proximal tibia are indicative of several musculoskeletal disorders involving changes in the bone quality and the surrounding soft tissue. Recent studies have shown that MR imaging also allows non-invasive 3-D characterization of bone microstructure. Sophisticated features like the scaling index method (SIM) can estimate local structural and geometric properties of the trabecular bone and may improve the ability of MR imaging to determine local bone quality in vivo. A set of 67 bone cubes was extracted from knee specimens and their biomechanical strength estimated by the yield stress (YS) [in MPa] was determined through mechanical testing. The regional apparent bone volume fraction (BVF) and SIM derived features were calculated for each bone cube. A linear multiregression analysis (MultiReg) and a optimized support vector regression (SVR) algorithm were used to predict the YS from the image features. The prediction accuracy was measured by the root mean square error (RMSE) for each image feature on independent test sets. The best prediction result with the lowest prediction error of RMSE = 1.021 MPa was obtained with a combination of BVF and SIM features and by using SVR. The prediction accuracy with only SIM features and SVR (RMSE = 1.023 MPa) was still significantly better than BVF alone and MultiReg (RMSE = 1.073 MPa). The current study demonstrates that the combination of sophisticated bone structure features and supervised learning techniques can improve MR-based determination of trabecular bone quality.     

Application of inversion voltammetry to microimpurity content control in synthetic sapphire

Modern methods of impurity control in synthetic sapphire were analyzed. An inversion voltametry method was suggested and an analysis algorithm was developed based on the example of zinc and copper. Special attention was paid to an extremely important stage, i.e., sample preparation. Experimental data on choosing electrochemical parameters of the analysis are presented.     

Abrasion of human enamel by brushing with a commercial dentifrice containing hydroxyapatite crystals in vitro.

Automatic toothbrushing with a commercial dentifrice containing hydroxyapatite (HAP) crystals was performed on the tangential polished surfaces of sound human enamel, mainly consisting of biological apatite similar to HAP, for 10 min in vitro. The X-ray diffraction peaks of HAP, brushite (DCPD), and monetite (DCP) crystals were detected from the dentifrice. After brushing, the enamel surfaces were observed with a scanning electron and a confocal scanning laser microscope. The brushing caused larger abrasive loss and more remarkable roughness of the enamel surfaces following the broad traces of brush bristles and the exposure of prism structures than brushing with a dentifrice containing only DCPD, which we previously reported. We claim that the fine granular-shaped HAP crystals of the dentifrice indicated as an active ingredient for preventing enamel caries possess stronger abrasivity of sound enamel than the DCPD and DCP as abrasives on account of their Mohs hardness values rather than sizes and shapes. The HAP crystals of dentifrices may not occlude the small defects of early caries enamel, but erode them more strongly as an abrasive than the other abrasives.     

Ultrastructural characteristics of bone marrow subendosteal region cells in T-cell virus-induced leukemia

The experiments were carried out to study hemopoietic and stromal cells of bone marrow subendosteal regions during T-cell lymphomagenesis in AKR mice, using transmission electron microscopy and electron microscopic immunocytochemistry methods. It is shown that the subendosteal region of mice with lympholeukosis is replaced by lymphocytes at different stages of differentiation with certain ultrastructural peculiarities. The association of alkaline-phosphatase positive reticulum cells with granulocytes is destroyed. The alkaline phosphatase activity in reticulum cells of the subendosteal region of mice with spontaneous lympholeukosis is very low or absent. The results obtained may be useful for understanding the AKR lymphomagenesis.