Melanin Distribution in Human Skin: Influence of Cytoskeletal,Polarity, and Centrosome-Related Machinery of Stratum basale Keratinocytes

Melanin granules cluster within supra-nuclear caps in basal keratinocytes (KCs) of the human epidermis, where they protect KC genomic DNA against ultraviolet radiation (UVR) damage. While much is known about melanogenesis in melanocytes (MCs) and a moderate amount about melanin transfer from MC to KC, we know little about the fate of melanin once inside KCs. We recently reported that melanin fate in progenitor KCs is regulated by rare asymmetric organelle movement during mitosis. Here, we explore the role of actin, microtubules, and centrosome-associated machinery in distributing melanin within KCs. Short-term cultures of human skin explants were treated with cytochalasin-B and nocodazole to target actin filaments and microtubules, respectively. Treatment effects on melanin distribution were assessed by the Warthin–Starry stain, on centrosome-associated proteins by immunofluorescence microscopy, and on co-localisation with melanin granules by brightfield microscopy. Cytochalasin-B treatment disassembled supra-nuclear melanin caps, while nocodazole treatment moved melanin from the apical to basal KC domain. Centrosome and centriolar satellite-associated proteins showed a high degree of co-localisation with melanin. Thus, once melanin granules are transferred to KCs, their preferred apical distribution appears to be facilitated by coordinated movement of centrosomes and centriolar satellites. This mechanism may control melanin’s strategic position within UVR-exposed KCs.     

井壁附近瞬态温度的数值计算方法

在石油钻井开采等过程中研究热量在地层中的传播具有很重要的意义。特别是在进行井漏机理研究中,利用它可以分析温度对井眼破裂压力、裂缝重启压力以及裂缝延伸压力的影响。本文使用有限差分法近似地求得近井壁地层的温度分布。利用此方法,可以求得任意时刻井壁温度随井深的分布,任意时刻、任意井深处井壁温度的径向分布,任意点温度随时间的变化,从而进一步了解温度在石油工程上的影响。     

涪陵页岩气录井解释评价关键技术

以涪陵页岩气田焦石坝区块首口参数井JY1井页岩岩心实验数据为基础,借鉴传统致密砂岩、碳酸盐岩油气层录井评价方法,形成适用于页岩气储集层的录井解释评价关键技术:钻时比值识别储层、钻时比值与烃对比系数交会图现场快速解释方法;页岩气储层孔隙度、渗透率、地层压力、地层破裂压力、游离气、吸附气及总含气量、脆性矿物含量等关键参数的计算模型;多参数定量类比的完钻综合解释方法。研究成果在涪陵页岩气田推广应用40多口井,效果良好。     

金1井安集海河组钻井液技术对策及措施

准噶尔盆地南缘地区地质条件复杂,钻井技术难度大,其中安集海河组最难对付.在分析安集海河组地层粘土矿物组成及水化性能基础上,提出了相应的钻井液技术对策,并针对金1井安集海河组的井下复杂情况采取了一系列技术措施,保证了该地层顺利钻进.     

富水圆砾地层中复合式土压平衡盾构施工技术

结合长沙地铁1号线2标段北辰三角洲站～开福寺站区间右线前220m盾构施工实例,分析富水圆砾地层对盾构施工的危害,提出了采取土体改良、同步注浆等技术措施预防可能出现的风险情况,对今后同类地质、水文条件下盾构隧道的安全施工积累了一定的经验。     

Uniformity of stratum‐ventilated thermal environment and thermal sensation

Three human test series were conducted to evaluate the uniformity of the thermal environments in a stratum‐ventilated chamber with dimensions of 8.8 m (L) × 5.1 m (W) × 2.4 m (H). In all, nineteen conditions were generated by adjusting the room temperature, supply airflow rate, and supply terminal type. An air diffuser performance index (ADPI) of at least 80% was achieved for most cases. This result shows that the air velocity and temperature in the occupied zone are reasonably uniform. Subjective assessments using the ASHRAE 7‐point scale indicate that the thermal sensations of the subjects in stratum ventilation are also uniform. This study examines the applicability of the predicted mean vote (PMV) model for evaluating stratum ventilation. When compared to the actual mean thermal sensation votes (ATS), the PMV values are acceptable. The PMV results at a height of 1.1 m above the floor show better agreement with the ATS than at a height of 0.1 m.     

Advantage of Sodium Polyoxyethylene Lauryl Ether Carboxylate as a Mild Cleansing Agent

Five anionic surfactants widely used in commercial skin cleansers were studied: sodium polyoxyethylene lauryl ether carboxylate (EC), sodium polyoxyethylene alkyl ether sulfate (ES), sodium dodecyl sulfate, potassium laurate, and N-cocoyl-l-glutamic acid monosodium salt. The amount of surfactant from aqueous solution adsorbed into the stratum corneum (SC), the degree of SC swelling, the change of the secondary structure of SC proteins (denaturation). The surface tension of surfactant–zein mixed solutions, and the solubilization behavior of zein were measured. Results showed that EC had the lowest adsorption into SC, the lowest SC swelling, and lowest denaturation of SC proteins. Low interactions between surfactants and SC proteins were also observed for EC/ES mixture solutions as well as. Mixing EC with ES good foaming performance. The EC/ES mixture, at about 1:1 ratio, is an excellent surfactant system for skin cleanser applications having cleansing characteristics and mildness to the skin.     

地层三维建模及OpenGL下三维可视化研究

地层三维重构及其三维可视化对地质信息的获取和地质解释具有十分重要的意义。对地层模型的三维重构进行了研究,提出了一种基于TIN的地层建模方法,有效地实现了地层模型的三维重构。该建模方法实现简单,构模速度快,适用范围广,并在OpenGL三维图形库下,实现了地层模型的三维可视化。     

Permeation enhancers for transdermal drug delivery

The transdermal route has been recognized as one of the highly potential routes of systemic drug delivery and provides the advantage of avoidance of the first-pass effect, ease of use and withdrawal (in case of side effects), and better patient compliance. However, the major limitation of this route is the difficulty of permeation of drug through the skin. Studies have been carried out to find safe and suitable permeation enhancers to promote the percutaneous absorption of a number of drugs. The present review includes the classification of permeation enhancers and their mechanism of action; thus, it will help in the selection of a suitable enhancer(s) for improving the transdermal permeation of poorly absorbed drugs.     

神经酰胺脂质体——含角质层脂质膜的脂质体

角质层的渗透屏障大多是由饱和脂质如神经酰胺、胆固醇和游离脂肪酸组成。它是物质交换的有效阻隔并防止皮肤干燥。神经酰胺脂质体(Cerasomes)是一种脂质体,它的膜是由最重要的角质层脂质组成的。神经酰胺脂质体作为类皮肤膜的来源,它能加快受损屏障层的再生、降低皮肤刺激,并且它还提供了将角质层脂质应用于化妆品中简单而有效的途径。