一种新兴的学科领域历史根源探究方法:RPYS

[目的/意义] 探索一个学科或研究领域的历史根源问题,找出对该学科领域起源具有重要作用的根源文献,对于学科的建设和研究具有重要意义。[方法/过程] 引入一种被称为“参考文献出版年图谱”（RPYS）的新方法,对其概念、特点和原理进行详细阐述,并将RPYS分析过程归纳为4个步骤。在此基础上,以健康信息素养研究领域为例,应用RPYS从参考文献的角度对该领域的历史根源文献进行识别和分析。[结果/结论] 结果表明,运用RPYS能够较为准确地揭示健康信息素养研究领域的历史根源文献,同时发现RPYS也可以用于学科或研究领域的研究热点、研究趋势的探究。     

The effects of skin and core tissue cooling on oxygenation of the vastus lateralis muscle during walking and running

Skin and core tissue cooling modulates skeletal muscle oxygenation at rest. Whether tissue cooling also influences the skeletal muscle deoxygenation response during exercise is unclear. We evaluated the effects of skin and core tissue cooling on skeletal muscle blood volume and deoxygenation during sustained walking and running. Eleven male participants walked or ran six times on a treadmill for 60 min in ambient temperatures of 22°C (Neutral), 0°C for skin cooling (Cold 1), and at 0°C following a core and skin cooling protocol (Cold 2). Difference between oxy/deoxygenated haemoglobin ([diffHb]: deoxygenation index) and total haemoglobin content ([tHb]: total blood volume) in the vastus lateralis (VL) muscle was measured continuously. During walking, lower [tHb] was observed at 1 min in Cold 1 and Cold 2 vs. Neutral (P?0.05). Lower [diffHb] was seen at 1 and 10 min in Cold 2 vs. Neutral by 13.5 ± 1.2 µM and 15.3 ± 1.4 µM and Cold 1 by 10.4 ± 3.1 µM and 11.1 ± 4.1 µM, respectively (P?0.05). During running, [tHb] was lower in Cold 2 vs. Neutral at 10 min only (P = 0.004). [diffHb] was lower at 1 min in Cold 2 by 11.3 ± 3.1 µM compared to Neutral and by 13.5 ± 2.8 µM compared to Cold 1 (P?0.001). Core tissue cooling, prior to exercise, induced greater deoxygenation of the VL muscle during the early stages of exercise, irrespective of changes in blood volume. Skin cooling alone, however, did not influence deoxygenation of the VL during exercise.     

Morphology of polyethylene ski base materials

Abstract

We used high-resolution Raman spectroscopy and differential scanning calorimetry for a comprehensive analysis of carbon black-filled polyethylene ski base grades at processing stages from the raw material to the structured ski base. Based on Raman mapping, we assessed the applicability of an advanced evaluation procedure for amorphous, disordered, and crystalline phase fractions of polyethylene for polyethylene extrusion and sinter grades. For sinter grades, a sufficient segregation between carbon black and polyethylene was confirmed, allowing for a comprehensive Raman spectroscopic morphological analysis. Significant morphological changes in polyethylene due to processing from the raw material to the semi-finished film and to the structured ski base were identified. Throughout the processing chain, we observed a decrease in crystallinity and an increase in the amorphous phase fraction. Although the raw material and the sintered semi-finished film exhibited a different but uniform polyethylene morphology, the morphological changes due to structuring of the ski base are limited to the top surface layer. The highest amorphous phase fractions were detected in the surface of the structured ski bases.     

ATR-FTIR imaging of albumen photographic prints

The preservation of early 20th century, late 19th century albumen prints is of great concern to collection managers and conservators of photographic materials. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopic imaging is presented for the first time as analytical methodology for the study of albumen photographs. This paper shows the feasibility of obtaining FTIR images of samples from albumen photographs with a high spatial resolution using a Ge ATR objective coupled with an infrared microscope. The improved spatial resolution compared to FTIR images obtained by the reflection method is due to the high refractive index of the ATR crystal, which gives a high numerical aperture and hence, a higher spatial resolution. The technique reveals detailed information on the organic functional group distribution in the individual layers of embedded cross sections and is used complementary to visual microscopy and scanning electron microscopy/energy dispersed X-ray spectroscopy. The main results of the study are discussed with regard to their historical and artistic significance, and they are compared with data from historical and conservation literature.     

评估普通人群肝脂肪变性磁共振成像定量方法的可行性

为了探讨采用3T西门子MRI LiverLab评估普通人群志愿者肝脏脂肪含量的可行性,招募了60名志愿者,其中双回波Dixon技术预测肝脂肪变性的患病率为51.7％(31/60),多回波Dixon和多回波HISTO技术测量的平均肝脏质子密度脂肪分数分别为(9.1±1.9)％和(9.3±2.3)％,测量结果在统计学上没有...     

The effects of 4 weeks normobaric hypoxia training on microvascular responses in the forearm flexor

Intermittent exposure to hypoxia can lead to improved endurance performance. Currently, it is unclear whether peripheral adaptions play a role in improving oxygen delivery and utilization following both training and detraining. This study aimed to characterize skeletal muscle blood flow (mBF), oxygen consumption (mV?O₂), and perfusion adaptations to i) 4-weeks handgrip training in hypoxic and normoxic conditions, and ii) following 4-weeks detraining. Using a randomised crossover design, 9 males completed 30-min handgrip training four times a week in hypoxic (14% FiO₂ ~ 3250m altitude) and normoxic conditions. mBF, mV?O₂ and perfusion were assessed pre, post 4-weeks training, and following 4-weeks detraining. Hierarchical linear modelling found that mV?O₂ increased at a significantly faster rate (58%) with hypoxic training (0.09 mlO₂·min^?1 · 100g^?1 per week); perfusion increased at a significantly (69%) faster rate with hypoxic training (3.72 μM per week). mBF did not significantly change for the normoxic condition, but there was a significant increase of 0.38 ml· min^?1 · 100ml^?1 per week (95% CI: 0.35, 0.40) for the hypoxic condition. During 4-weeks detraining, mV?O₂ and perfusion significantly declined at similar rates for both conditions, whereas mBF decreased significantly faster following hypoxic training. Four weeks hypoxic training increases the delivery and utilisation of oxygen in the periphery.     

荧光法测定脑组织单胺类递质和有关技术问题及其在运动医学中的应用

单胺类递质在大脑许多功能的控制调节中起重要作用,测定不同状态下脑内单胺类递质可了解这类递质在不同状态下脑内的合成、释放和转化,是探索运动性中枢疲劳和有关药物作用机制的重要手段。荧光测定法因其特异性高、操作简单、费用较低等特点,具有广阔的应用前景。但实验中许多值得注意的技术问题和环节影响测定的结果,通过查阅有关文献并结合实验中的影响因素,对其测定的原理、方法和值得注意的有关技术问题及其在医学和生物学中的应用进行梳理和归纳,旨在为应用领域和实验方法学提供理论指导和技术支持。     

橙皮素的制备

橙皮素是一类重要的天然黄酮类化合物.报道了由橙皮苷制备橙皮素的方法,并对其反应机理进行研究.采用一维红外光谱和二阶导数红外光谱对橙皮苷和橙皮素的结构进行了表征.     

紫外光谱技术在食品分析中的应用

紫外光谱技术是化学分析中常用的一种方法,被广泛用于有机、生化、石油、药物、环境等领域,其在食品分析中的应用包括紫外光谱法在鉴别食品中的应用,具体为鉴别食品含量、食品质量和食品种类方面的应用．紫外可见光谱分析技术具有速度快、效率高、成本低、测量方便等特点,已经被越来越多地应用于食品工业,应用前景广泛．     

自激荧光在污染水体中轻重金属离子检测研究

受污染水体中很少存在单一的污染源,导致污染水体中混合污染源难以确定与区分。研究一种在多污染源中各种金属离子的确定和检测问题。提出了采用自激荧光对受污染水体进行检测,对污染物中混有轻重金属的污染水体分别检测,对重金属污染物采用紫外光谱吸收与荧光光谱吸收检测,对轻金属污染物自激荧光光谱检测。形成了活泼金属离子的检测与治理方法,通过分析自激荧光在猝灭过程中产生的特殊光谱特性来进行不同污染物种的金属离子判断,采用紫外光对重金属离子进行二次判断,以达到快速检测的目标。实验结果表明,检测方法能有效检测污染水体中的各金属离子,对受污染水体的判断具有较好的指导性。