利用近红外光谱监测皮肤血氧输运

利用近红外光谱无创监测移植手术的皮瓣成活状况，是近红外组织氧检测技术的最新应用之一，本文介绍子我们设计的利用光纤传导的近外皮肤血氧监测系统。该系统可以灵活调整光谱－探测器间距以适应皮层检测。利用该系统进行的前臂皮皮肤阻断试验中，静脉阻断时皮肤内有显著的血液充盈现现象，全阻断时氧含量明显下降，实验表明，利用近红外光谱法监测瓣血氧输运情况是非常有效的，特别是可以比较好地监测脉回流情况。     

Sakiadis flow of an upper-convected Maxwell fluid

The flow of an upper-convected Maxwell (UCM) fluid is studied theoretically above a rigid plate moving steadily in an otherwise quiescent fluid. It is assumed that the Reynolds number of the flow is high enough for boundary layer approximation to be valid. Assuming a laminar, two-dimensional flow above the plate, the concept of stream function coupled with the concept of similarity solution is utilized to reduce the governing equations into a single third-order ODE. It is concluded that the fluid's elasticity destroys similarity between velocity profiles; thus an attempt was made to find local similarity solutions. Three different methods will be used to solve the governing equation: (i) the perturbation method, (ii) the fourth-order Runge-Kutta method, and (iii) the finite-difference method. The velocity profiles obtained using the latter two methods are shown to be virtually the same at corresponding Deborah number. The velocity profiles obtained using perturbation method, in addition to being different from those of the other two methods, are dubious in that they imply some degree of reverse flow. The wall skin friction coefficient is predicted to decrease with an increase in the Deborah number for Sakiadis flow of a UCM fluid. This prediction is in direct contradiction with that reported in the literature for a second-grade fluid.     

Effect of surface preparation on the strength of vibration welded butt joint made from PBT composite

Vibration welding technique has been widely used to weld molded surfaces parts produced by injection or compression molding techniques. However, the majority of early studies used machined surfaces to eliminate the complication associated with molded surfaces. Different process parameters such as the welding pressure, frequency, and amplitude have been investigated to determine their optimal values that maximize the welding strength. However, some other parameters such as joint design and the welding interface preparation were leftover for real application test or for technology transfer studies. Most of molded parts from semi-crystalline materials and their composites usually have skin layer that was exposed to thermal history differs from that of the core. Moreover, the amount and the orientation of fibers in the skin layer differ from that of core and shell regions. Therefore, this work investigates and explores the effect of the molded surfaces with skin on tensile strength of vibration welded butt joints made from polybutylene terephthalate reinforced with 30% glass fiber (PBT GF30). The effect of fibers orientation on the welded joint strength has been also investigated.     

The dose and X-ray energy response of LiF:Mg,Cu,P and CaSO4:Dy thermoluminescent foils

Within a systematic study of a novel system enabling 2D readout of TL foils, the X-ray energy and dose response was investigated in TL foils containing LiF:Mg,Cu,P (MCP-N) or CaSO4:Dy as activators. Foils were exposed to broad X-ray beams of mean energies ranging between 45 keV and 208 keV (ISO 4037 standard), with reference to 662 keV ¹³⁷Cs gamma rays. The MCP-N foils, of about 380 nm emission wavelength, show a flat X-ray energy response, but low sensitivity. Due to poor TL light detection efficiency of the CCD (charge-coupled device) camera over this range of wavelengths, only doses exceeding 500 mGy can be reliably measured. In the case of CaSO4:Dy foils, their TL light emitted around 450 nm wavelengths is registered by the CCD camera with no loss of efficiency, enabling X-ray doses as low as 100 mGy to be evaluated. Unlike that of MCP-N, the dose response of CaSO4:Dy foils is highly supralinear. Nevertheless, within experimental conditions applied in this study, the 2D-TL technique may be applied to determine Entrance Surface Dose or Maximum Skin Dose in radiology. The more sensitive CaSO4:Dy foils could be used only in a well-specified radiation field (e.g., in mammography) or in qualitative dose mapping.     

An improved continuum skin and proximity effect model for hexagonally packed wires

This work presents approximate but closed-form expressions for “effective” complex-valued magnetic permeability and electric conductivity that represent the effects of proximity and skin effect losses in wound coil with hexagonally packed wires. Previous work is extended by providing improved accuracy versus finite element results for effective permeability and by providing an expression for effective conductivity, which was previously neglected. These material properties can then be used in 2D/axisymmetric finite element models in which the coil is modeled as a coarsely meshed, homogeneous region (i.e., removing the need for modeling each turn in the coil).     

橙皮中橙皮苷的分光光度法测定

建立了分光光度测定橙皮中橙皮苷含量的简便方法。橙皮苷和Al(NO3)3水溶液反应后生成的络合物在420nm处有最大吸收,在0—100μg/mL的浓度范围内吸光度具有良好的线性关系。可用于分光光度测定橙皮中橙皮苷。方法简单、快速,具有处理量大的优点。     

In vivo molecular evaluation of guinea pig skin incisions healing after surgical suture and laser tissue welding using Raman spectroscopy

The healing process in guinea pig skin following surgical incisions was evaluated at the molecular level, in vivo, by the use of Raman spectroscopy. After the incisions were closed either by suturing or by laser tissue welding (LTW), differences in the respective Raman spectra were identified. The study determined that the ratio of the Raman peaks of the amide III (1247 cm⁻¹) band to a peak at 1326 cm⁻¹ (the superposition of elastin and keratin bands) can be used to evaluate the progression of wound healing. Conformational changes in the amide I band (1633–1682 cm⁻¹) and spectrum changes in the range of 1450–1520 cm⁻¹ were observed in LTW and sutured skin. The stages of the healing process of the guinea pig skin following LTW and suturing were evaluated by Raman spectroscopy, using histopathology as the gold standard. LTW skin demonstrated better healing than sutured skin, exhibiting minimal hyperkeratosis, minimal collagen deposition, near-normal surface contour, and minimal loss of dermal appendages. A wavelet decomposition–reconstruction baseline correction algorithm was employed to remove the fluorescence wing from the Raman spectra.     

柚子皮挥发油化学成分分析

使用水蒸气蒸馏法提取柚子皮中的挥发油,利用气相色谱-质谱联用技术对柚子皮化学成分进行分离鉴定,采用色谱峰面积归一化法确定各成分的相对含量。分析结果表明,共检测出62种组分,鉴定了其中的31种组分,占挥发油组分总量的50.0%。主要成分是β-蒎烯、4,4A,5,6,7,8-六氢-4,4A-二甲基-6-(1-甲基亚乙基)-(4R-顺)-2(3H)-萘酮、氧化芳樟醇、(E,E)-3,7,11,15-四甲基-1,6,10,14-十六碳四烯-3-醇。