胶原在组织工程人工皮肤中的应用

作为生物相容性良好的医用材料，胶原被广泛应用于人工皮肤。文中介绍了胶原基人工皮肤的特点、应用形式和国内外的研究情况。     

客车蒙皮组焊件焊接工艺的改进

针对西安某汽车厂客车蒙皮组焊件焊接采用CO2气体保护焊生产率低、焊接变形大、表面处理难度大、质量难以保证的问题，本文作者对其进行了工艺改进，通过采用全自动缝焊焊接工艺及选择合理的工艺规范参数，在保证结构和强度的前提下，使蒙皮组焊件焊接表面质量大幅提高，劳动强度大幅下降，生产率提高数倍。     

变压式皮肤听声器的初步研究

运用生理学与电子学理论并通过实验设计了一种变压式皮肤听声器，它可以使全聋人通过皮肤获得对于声音的听觉。文中还将皮肤听声器的设计原理与助听器及电子耳蜗的设计原理做了对比。     

Comparison of Operant Escape and Innate Reflex Responses to Nociceptive Skin Temperatures Produced by Heat and Cold Stimulation of Rats.

In behavioral tests, rats performed learned escape responses to thermal stimulation of the paws by 44.0. 47.0. or 0.3 degrees C. Licking, guarding, and jumping reflexes were evaluated at these temperatures. The frequency, latency, and duration of escape and reflex responses were compared and were related to hind-paw skin temperatures measured during stimulation of awake and anesthetized rats. The duration and latency of escape from heat were appropriately related to stimulus intensity. Escape occurred reliably for each intensity. Reflexes occurred unreliably and at long latency to 44.0 or 0.3 degrees C and were not appropriately related to heat intensity. The reflexes were relatively insensitive to thermal nociceptive stimulation other than heating of the skin at a high rate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于肤色模型和椭圆环模板的人脸跟踪及姿态估计

文章提出了一种基于肤色模型,结合椭圆环模板进行人脸跟踪及姿态估计的算法。该算法在基于肤色模型实现人脸跟踪及特征定位的过程中首先利用肤色模型定位人脸肤色区域,在跟踪中增加了自适应学习模块,使得原始的肤色模型能够在不同光照下实现自适应调整。然后利用人脸形状的先验知识,通过椭圆环模板实现人脸边缘的精确定位。最后根据所得到的面部特征和人脸边缘位置估计出人脸的姿态。实验表明,该算法能够在自然光照条件下取得较为满意的跟踪结果,同时对人脸在旋转、缩放、遮挡等条件下,多人脸背景下的跟踪有较强的鲁邦性。     

Blind colour separation of H&E stained histological images by linearly transforming the colour space

Blind source separation methods aim to split information into the original sources. In histology, each dye component attempts to specifically characterize different microscopic structures. In the case of the hematoxylin–eosin stain, universally used for routine examination, quantitative analysis may often require the inspection of different morphological signatures related mainly to nuclei patterns, but also to stroma distribution. Stain separation is usually a preprocessing operation that is transversal to different applications. This paper presents a novel colour separation method that finds the hematoxylin and eosin clusters by projecting the whole space to a folded surface connecting the distributions of a series of planes that divide the cloud of H&E tones. The proposed method produces density maps closer to those obtained with the colour mixing matrices set by an expert, when comparing with the density maps obtained using nonnegative matrix factorization (NMF), independent component analysis (ICA) and a state‐of‐the‐art method. The method has outperformed three baseline methods, NMF, Macenko and ICA, in about 8%, 12% and 52% for the eosin component, whereas this was about 4%, 8% and 26% for the hematoxylin component.     

Synthesis and transdermal permeation of novel N4-methoxypoly(ethylene glycol) carbamates of cytarabine

Background: Cytarabine is a deoxycytidine analogue commonly used in the treatment of hematological malignant diseases. Its clinical utility, however, is severely limited by its short plasma half-life because of the catabolic action of nucleoside deaminases. Method: In this study, N⁴-carbamate derivatives of cytarabine (1) were synthesized and evaluated for transdermal penetration because this mode of administration may circumvent its limitations. The synthesis of these compounds was achieved in a two-step process. First, the methoxypoly(ethylene glycol) was activated by p-nitrophenyl chloroformate. Second, the activated intermediates were reacted with cytarabine in the presence of N-hydroxysuccinamide to give the N⁴-methoxypoly(ethylene glycol) carbamate derivatives. The transdermal flux values of the N⁴-carbamates of cytarabine were determined in vitro by Franz diffusion cell methodology. Aqueous solubility and log D (pH 7.4) values were determined and assessed for correlation with transdermal flux values. Results: The synthesized carbamates, particularly, (9)–(13), showed increased solubility in both aqueous and lipid media. Log D values decreased as the oxyethylene chain lengthened. Conclusion: Although none of the derivatives showed significantly higher transdermal penetration than cytarabine (1), it should be mentioned that the mean for cytarabine N⁴-methoxyethyleneoxycarbamate (8) was 10 times higher and the median was 2 times higher.     

Metronidazole-loaded nanostructured lipid carriers to improve skin deposition and retention in the treatment of rosacea

The objective of the present investigation was to improve the skin deposition and retention of metronidazole (MTZ) in rosacea therapy by incorporating it into nanostructured lipid carriers (NLCs). The main challenge in this endeavor was the partial hydrophilicity of MTZ, which mandated careful selection of excipients, including solid and liquid lipids, surfactants, and their ratios in combination. NLCs were produced by the phase inversion temperature method and finally converted into a gel for topical application. The prepared nanoparticles were evaluated for their particle size, zeta potential, entrapment efficiency, solid-state characteristics, surface morphology, in vitro drug release, and permeation through excised skin. The gel was additionally characterized for its pH, drug content, viscosity, and spreadability. The prepared nanoparticles were spherical in shape and of size less than 300?nm. Incorporation of judiciously chosen excipients made possible a relatively high entrapment efficiency of almost 40%. The drug release was found to be biphasic, with an initial burst release followed by sustained release up to 8?hours. In comparison to the plain drug gel, which had a tissue deposition of 11.23%, the NLC gel showed a much superior and desirable deposition of 26.41%. The lipophilic nature of the carrier, its size, and property of occlusion enabled greater amounts of drug to enter and be retained in the skin, simultaneously minimizing permeation through the skin, i.e. systemic exposure. The results of the study suggest that NLCs of anti-rosacea drugs have the potential to be used in the therapy of rosacea.     

Electrically controlled release of 5-fluorouracil from conductive gelatin methacryloyl-based hydrogels

Herein, electro-responsive hydrogels were obtained by incorporation of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) into the gelatin methacryloyl (GelMA) by using photopolymerization technique. Hydrogels were characterized by FTIR and scanning electron microscopy analyses. Cytotoxicity tests were performed by L929 cell lines to determine cell compatibility. Swelling tests were conducted to investigate the water uptake capacity of hydrogels. 5-fluorouracil (5-FU) was selected as a model drug as it is known as a topical drug for some skin cancer type treatment. The release of 5-FU from the hydrogel was provided in efficient and controlled manner at simulated skin cancer (pH = 5.5) and under 0 and 1.5 V. The simulated drug delivery experiments conducted in vitro revealed that the drug releasing amount was higher when voltage is applied to the hydrogels. All results visualized that the obtained GelMA-based PEDOT/PSS hydrogels with enhanced electrical properties could be a potential candidate as an electrically sensitive drug carrier for treatment of skin cancer in the future applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46914.     

The effect of an amphiphilic self‐assembled lipid lamellar phase on the relief of dry skin

Humectant and occlusive technologies have traditionally been used for the treatment of dry skin. Originally, non‐lamellar‐forming ingredients were used such as petrolatum but recent research has shown the advantage of using lamellar‐forming ingredients such as ceramides, pseudoceramides and phospholipids in the relief of dry skin. Nevertheless, the importance of using lipid‐phase transition inducers, such as long‐chain fatty acids, has not been studied clinically. The evaluation of a novel complex of lipophilic ingredients was of interest: cetyl alcohol, isostearyl isostearate, potassium cetyl phosphate, cetyl behenate and behenic acid. The combination of all these ingredients was shown to be more effective than any single component in water vapour transmission rate studies. This was thought to be owing to the formation of a unique structural organization of the lipids upon dry‐down from an O/W emulsion as was examined by X‐ray diffraction and optical microscopy. When evaluated clinically in a randomized double‐blind and vehicle‐controlled moisturization efficacy trial, this novel blend of ingredients was shown to not only improve the visible signs of skin dryness to a significantly greater extent than a comparable mineral oil‐containing vehicle but also then maintain a better skin condition during the regression no‐treatment phase of the study. This combination of ingredients offers a new technology option for the treatment of dry skin.