Effect of the Surface Morphology of Porous Coatings on Secondary Electron Yield of Metal Surface

Surface roughening is an important material surface treatment technique, and it is particularly useful for use in secondary electron yield (SEY) suppression on metal surfaces. Porous structures produced via roughening on coatings have been confirmed to reduce SEY, but the regulation strategy and the influence of process parameters both remain unclear in the practical fabrication of effective porous structures. In this paper, the effect of the surface morphology of porous coatings on the SEY of aluminum alloy substrates was studied. Surface characterization and SEY measurements were carried out for samples with a specific process technique on their surfaces. An exponential fitting model of the correlation between surface roughness and the peak values of SEY curves, δm, was summarized. Furthermore, an implementation strategy to enable low surface SEY was achieved from the analysis of the effect of process parameters on surface morphology formation. This work will aid our understanding of the effect of the irregular surface morphology of porous coatings on SEY, thereby revealing low-cost access to the realization of an easy-to-scale process that enables low SEY.     

哈萨克族宫颈癌临床病理分析

目的:探讨阿勒泰地区哈萨克族子宫颈癌临床病理特点.方法:对本地区1995年1月～2006年2月收治的94例哈萨克族子宫颈癌活检及手术切除标本与33例汉族进行对比分析,探讨子宫颈癌患者的发病特点及防治措施.结果:127例子宫颈癌患者中哈萨克族与汉族病理组织学类型对比差异无显著性(χ2=1.56,P＞0.05),子宫颈癌发病率随着年龄的增加而增高.结论:子宫颈癌已严重危害我区女性健康,应在本地区对35岁以上的女性定期行宫颈涂片检查,提高自我保健意识和防病意识.     

基线尿酸及NT-proBNP水平与心房颤动的射频消融复发率关系的研究

目的探讨传统的生物学标记物,如NT-pro BNP和血尿酸(SUA)与心房颤动射频消融术后心律失常复发的关系。方法随机入选2013年1月至2014年10月间在航天中心医院接受第一次心脏心房颤动射频消融术的61例患者的临床资料。其中阵发性心房颤动(持续时间<7 d)患者39例(63.9%),持续性心房颤动(7 d<持续时间<1年)13例(21.3%),永久性心房颤动(持续时间>1年)的患者9例(14.8%)。检测各组NT-pro BNP和SUA水平。结果复发组与未复发组分别为13例(21.3%)和48例(78.7%)。与未复发组比,复发组患者年龄、左房前后径、冠心病比例、吸烟史比例及既往心房颤动时间均更高;入院时NT-pro BNP和SUA水平均更高(P<0.01)。NT-pro BNP和SUA水平与消融术后心房颤动的复发呈正相关(r分别为0.46、0.32,P<0.05)。结论 NT-pro BNP的升高提示心室张力增加或存在心房限制性疾病,是消融术后复发的可能原因。SUA具有促炎、促氧化作用,提示炎症和氧化应激在消融术后的复发可能起重要作用。     

徐州市脑卒中患者生存质量及相关因素研究

目的研究徐州市脑卒中患者的生存质量(QOL)状况及相关因素。方法采用随机整群抽样方法抽取徐州市4所医院为研究中心,采用自编调查问卷及脑卒中患者生存质量量表(QOLISP)进行评估。结果调查的303名脑卒中患者的生存质量总分为(115.8±16.6)分,处于中等水平。单因素分析显示文化程度低、未康复治疗、基础健康差、康复信心缺乏的患者生存质量差;多因素分析表明基础健康和信心是生存质量的主要影响因素。结论重视医疗保健水平、开展综合护理、健康教育、树立信心、建立符合当地医疗水平的"卒中单元"有利于提高生存质量。     

SRS-FISH: A high-throughput platform linking microbiome metabolism to identity at the single-cell level

One of the biggest challenges in microbiome research in environmental and medical samples is to better understand functional properties of microbial community members at a single-cell level. Single-cell isotope probing has become a key tool for this purpose, but the current detection methods for determination of isotope incorporation into single cells do not allow high-throughput analyses. Here, we report on the development of an imaging-based approach termed stimulated Raman scattering–two-photon fluorescence in situ hybridization (SRS-FISH) for high-throughput metabolism and identity analyses of microbial communities with single-cell resolution. SRS-FISH offers an imaging speed of 10 to 100 ms per cell, which is two to three orders of magnitude faster than achievable by state-of-the-art methods. Using this technique, we delineated metabolic responses of 30,000 individual cells to various mucosal sugars in the human gut microbiome via incorporation of deuterium from heavy water as an activity marker. Application of SRS-FISH to investigate the utilization of host-derived nutrients by two major human gut microbiome taxa revealed that response to mucosal sugars tends to be dominated by Bacteroidales, with an unexpected finding that Clostridia can outperform Bacteroidales at foraging fucose. With high sensitivity and speed, SRS-FISH will enable researchers to probe the fine-scale temporal, spatial, and individual activity patterns of microbial cells in complex communities with unprecedented detail.

With the rapid advances in both genotyping and phenotyping of single cells, bridging genotype and phenotype at the single-cell level is becoming a new frontier of science (1). Methods have been developed to shed light on the genotype–metabolism relationship of individual cells in a complex environment (2, 3), which is especially relevant for an in-depth understanding of complex microbial communities in the environment and host-associated microbiomes. For functional analyses of microbial communities, single-cell isotope probing is often performed in combination with nanoscale secondary ion mass spectrometry (NanoSIMS) (4–7), microautoradiography (MAR) (8, 9), or spontaneous Raman microspectroscopy (10–12) to visualize and quantify the incorporation of isotopes from labeled substrates. These methods can be combined with fluorescence in situ hybridization (FISH) using ribosomal ribonucleic acid (rRNA)-targeted probes (13), enabling a direct link between metabolism and identity of the organisms. In addition, Raman-activated cell sorting has been recently developed using either optical tweezers or cell ejection for downstream sequencing of the sorted cells (14–16). While these approaches have expanded the possibilities for functional analyses of microbiome members (17), all of the aforementioned methods suffer from extremely limited throughput. Consequently, only relatively few samples and cells per sample are typically analyzed in single-cell stable isotope probing studies, hampering a comprehensive understanding of the function of microbes in their natural environment.To overcome the limited throughput of Raman spectroscopy, coherent Raman scattering microscopy based on coherent anti-Stokes Raman scattering (CARS) or stimulated Raman scattering (SRS) has been developed (18, 19). Compared with CARS, the SRS signal is free of the electronic resonance response (20) and is linear to molecular concentration, thus permitting quantitative mapping of biomolecules (21, 22). Both CARS and SRS microscopy have successfully been applied for studying single-cell metabolism in eukaryotes (23–26). In a label-free manner, SRS imaging has led to the discovery of an aberrant cholesteryl ester storage in aggressive cancers (27, 28), lipid-rich protrusions in cancer cells under starvation (29), and fatty acid unsaturation in ovarian cancer stem cells (30) and more recently, in melanoma (31, 32). CARS and SRS have also been harnessed to explore lipid metabolism in live Caenorhabditis elegans (33–36). Combined with stable isotope probing, SRS microscopy has allowed the tracing of glucose metabolism in eukaryotic cells (37, 38) and the visualization of metabolic dynamics in living animals (25). Recently, SRS was successfully applied to infer antibiotic resistance patterns of bacterial pure cultures and heavy water (D2O) metabolism (39). Yet, SRS microscopy has not been adapted for studying functional properties of members of microbiomes as SRS itself lacks the capability of identifying cells in a complex community.Here, we present an integrative platform that exploits the advantages of SRS for single-cell stable isotope probing together with two-photon FISH for the identification of cells in a high-throughput manner. To deal with the challenges in detecting low concentrations of metabolites inside small cells with diameters around 1 µm, we have developed a protocol that maximizes the isotope label content in cells and exploits the intense SRS signal from the Raman band used for isotope detection.Conventionally, FISH is performed separately by one-photon excited fluorescence microscopy (40). To enhance efficiency, we developed a system that implements highly sensitive SRS metabolic imaging with two-photon FISH using the same laser source. These efforts collectively led to a high-throughput platform that enables correlative imaging of cell identity and metabolism at a speed of 10 to 100 ms per cell. In comparison, it takes about 20 s to record a Raman spectrum from a single cell in a conventional spontaneous Raman FISH experiment (41, 42).Our technology enabled high-throughput analysis of single-cell metabolism in the human gut microbiome. In the human body, microbes have been shown to modulate the host’s health (43, 44). Analytical techniques looking into their activities and specific physiologies (i.e., phenotype) as a result of both genotype and the environment provide key information on how microbes function, interact with, and shape their host. As a proof of principle, we used stimulated Raman scattering–two-photon fluorescence in situ hybridization (SRS-FISH) to track the incorporation of deuterium (D) from D2O into a mixture of two distinct gut microbiota taxa. Incorporation of D from D2O into newly synthesized cellular components of active cells, such as lipids and proteins, occurs analogously to incorporation of hydrogen from water during the reductive steps of biosynthesis of various cellular molecules (10, 45, 46). Importantly, D incorporation from D2O has been shown to be reliable to track metabolic activity of individual cells within complex microbial communities in response to the addition of external substrates (10, 17, 47). When microbial communities are incubated in the presence of D2O under nutrient-limiting conditions, individual cells display only minimal activity and only minor D incorporation (11, 17, 47). In contrary, when cells are stimulated by the addition of an external nutrient, cells that can metabolize this compound become active and incorporate D into macromolecules, which lead to the presence of C-D bonds into the cell’s biomass. Consequently, D incorporation from D2O can be combined with techniques able to detect C-D signals, such as Raman-based approaches, and to track metabolic activity at the single-cell level in response to a variety of compounds. Here, we show that SRS-FISH enables fast and sensitive determination of the D content of individual cells while simultaneously unveiling their phylogenetic identity. We applied this technique to complex microbial communities by tracking in situ the metabolic responses of two major phylogenetic groups of microbes in the human gut (Bacteroidales and Clostridia spp.) and of a particular species within each group to supplemented host-derived nutrients. Our study revealed that 1) Clostridia spp. can actually outperform Bacteroidales spp. at foraging on the mucosal sugar fucose and shows 2) a significant interindividual variability of responses of these major microbiome taxa toward mucosal sugars. Together, our results demonstrate the capability of SRS-FISH to unveil the metabolism of particular microbes in complex communities at a throughput that is two to three orders of magnitude higher than other metabolism identity bridging tools, therefore providing a valuable multimodal platform to the field of single-cell analysis.     

磷酸氯喹致飞蚊症和腹泻的文献复习

目的 通过1例飞蚊症和腹泻的药物不良反应,探索磷酸氯喹治疗新型冠状肺炎的药学监护要点.方法 询问患者和医生,查阅文献,对照不良反应因果关系.结果 磷酸氯喹治疗新冠肺炎的日剂量大于不良反应文献报道及美国眼科学会推荐的视网膜安全剂量,磷酸氯喹的眼毒性与单次剂量和疗程有关.结论 建议治疗前行眼部基线检查,治疗中加强监测.     

Mechanical Reinforcement in Nylon 6 Nanocomposite Fiber Incorporated with Dopamine Reduced Graphene Oxide

The emergence of graphene-based polymer composite fibers provides a new opportunity to study the high-performance and functional chemical fibers. In this work, we have developed an efficient and convenient method with polydopamine (PDA) to functionalize and reduce graphene oxide (GO) simultaneously, and the modified graphene nanosheets can obtain uniform dispersion and strong interfacial bonding in nylon 6 (PA6). Furthermore, the reinforced PA6 composite fibers were prepared through mixing PDA-rGO into the PA6 polymer matrix and then melt spinning. The functional modification was characterized by surface analysis and structural testing including SEM, TEM, FTIR, and Raman. When the addition amount of the modified GO was 0.15 wt%, the tensile strength and Young’s modulus of the composite fiber reached 310.4 MPa and 462.3 MPa, respectively. The results showed a meaningful reinforcement with an effect compared to the pure nylon 6 fiber. Moreover, the composite fiber also exhibited an improved crystallinity and thermal stability, as measured by DSC and TGA.