FINITE ELEMENT METHOD ON NUMERICAL SIMULATION OF STRATUM CORNEUM'S PENETRATION PROPERTY

How the outer substance could penetrate through the skin lies in the stratum corneum, because it is the main barrier in the multi-layers of the skin. Supposing the keratin cell with a special geometry as tetrakaidecahedron, the penetration property of stratum corneum was the key problem which was numerically simulated with finite element method. At first the discretization of the stratum corneum region was given in two steps： first, the discretization of the keratin cell; second, the discretization of fattiness that surrounds the keratin. Then there was the work of numerical simulation. In this procedure, the finite element method and the multi-grid method were used. The former was to obtain the discretization of basic elements; the latter was to decrease the high frequency error. At last the visualization of the numerical simulation was shown.

Surface modification of stratum corneum for drug delivery and skin care by microplasma discharge treatment

Human skin is the largest organ and also the main barrier that prevents foreign substances from entering the body.The surface properties of the skin are relevant for transdermal drug delivery and cosmetics.Yucatan micropig skin is used as a substitute for human skin.A microplasma electrode is used for surface modification of the skin epidermal layer of the Yucatan micropig.Microplasma dielectric barrier discharge has a thin dielectric as a barrier (~50 μm) and a frequency of 25 kHz.The surface properties of the epidermal layer were characterized by the measurement of the contact angle of the water droplet.The effects of different gases such as air,nitrogen,oxygen,helium or argon were compared.The change of the contact angle is temporal and it is returned to its initial state after several hours.Among the gases used for plasma ignition,oxygen and argon were the most effective for skin treatment.The distance of the skin from the electrode and the treatment time played a crucial roles in the increasing water contact angle.Changes of surface atomic concentration were determined by x-ray photoelectron spectroscopy.After microplasma treatment,the oxygen and nitrogen concentration increased at the skin surface.

A Consensus Modeling Approach for the Determination of Stratum Corneum Thickness Using In-Vivo Confocal Raman Spectroscopy

The measurement of stratum corneum (SC) thickness from in-vivo Raman water concentration depth profiles is gaining in popularity and appeal due to the availability and ease of use of in-vivo confocal Raman measurement systems. The foundation of these measurements relies on high-quality confocal Raman spectroscopy of skin and the robust numerical analysis of water profiles, which allow for accurate determination of SC thickness. These measurements are useful for studying intrinsic skin hydration profiles at different body sites and for determining hydration properties of skin related to topically applied materials. While the use of high-quality in-vivo Raman instrumentation has become routine and its use for SC thickness measurement widely reported, there is lack of agreement as to the best method of computing SC thickness values from Raman water profiles. Several methods have been proposed and are currently in use for such computations, but none of these methods has been critically evaluated. The work reported in this paper describes a new method for the determination of stratum corneum thickness from in-vivo confocal Raman water profiles. The method represents a consensus approach to the problem, which was found necessary to apply in order to properly model and quantify the large diversity of water profile types encountered in typical in-vivo Raman water measurement. The methodology is evaluated for performance using three criteria: 1) frequency of minimum fitting error on modeling to a standard numerical function;2) frequency of minimum model error for consensus vs. individual SC thickness values;and 3) correlation with reflectance confocal microscopy (RCM) values for SC thickness. The correlation study shows this approach to be a reasonable replacement for the more tedious and time-consuming RCM method with R2 = 0.68 and RMS error = 3.7 microns over the three body sites tested (cheek, forearm and leg).

Influence of short chain ceramides and lipophilic penetration enhancers on the nano-structure of stratum corneum model membranes studied using neutron diffraction

Oriented stratum corneum model lipid membranes were used to study the influence of the short chain ceramides （CER）[NP] and [AP] as well as the impact of the lipophilic penetration enhancer molecules oleic acid （OA） and isopropyl myristate （IPM） on the lipid nanostrueture. The influence of the enhancer molecules were studied using specifically deuterated OA and IPM and neutron diffraction. 2H NMR spectroscopy was used to study the impact of the ceramides＇ degree of order within the stratum corneum model lipid membranes. It was found that CER[NP] forms two very stable phases with high resistance against temperature increase. Phase B showed unusual hydration behavior as no water uptake of this phase was observed. The 2H NMR spectroscopic measurements showed that CER[NP] based ternary model system had a higher state of lamellar order in comparison to CER[AP] based lipid matrix. The studies confirmed that the short chain ceramides, particularly CER[NP], have a very high impact on the integrity of the Stratum comeum lipid bilayers. The penetration enhancer OA has not influenced the repeat distance of the model membrane based on CER[AP], and was not able to induce a phase separation in the investigated lipid matrix. However, a disorder and a fluidisation of the model membranes were observed when OA was incorporated. IPM showed the same effect but two phases （assigned as phase A and B） appeared, when IPM was used as penetration enhancer and incorporated into the model membrane. Furthermore, two arrangements of IPM were identified in phase A using deuterated IPM. A model of the nanostructure of the Stratum corneum lipid membranes is presented.

Different Modes of the Effect of 1,2-Propanediol and Azone on Stratum Corneum Lipids

The stratum corneum (SC) controls the diffusion and penetration of drugs into and through the skin. In this investigation, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were used to study the effect of two enhancers, 1,2 propanediol and azone, on lipids extracted from SC (SC lipids). The two enhancers affected the SC lipids. However, their function modes were different. The penetration enhancing mechanisms of the two enhancers are discussed based on their effects on SC lipids and on their efficiencies in arbutin permeation enhancement.

TEM Assessments of the Restructuring Effects of an Emollient Cream on the <i>stratum corneum</i>

The structure of the stratum corneum contributes to the barrier function of the epidermis. Skin barrier recovery is of utmost importance after epidermal tissue damage. The aim of this study was to describe, at the cellular level, the structural effects resulting from topical application of a hand-cream onto normal skin and to investigate the potential repair mechanisms induced by the emollient on altered tissue. Transmission electron microscopy (TEM) was used to compare the architectures of the horny layers from: 1) ex-vivo cultured human skin;2) skin treated by topical application of a hand-cream emulsion;3) explants exposed to sodium lauryl sulfate (SLS);4) SLS-treated explants that underwent subsequent topical application of the emollient emulsion. These TEM assessments allowed identifying the structural changes occurring in the stratum corneum of skin explants exposed to SLS and/or treated with an emollient. Results strongly suggest that both, SLS-induced damage and emollient-driven repair process take place in the stratum corneum, at the cellular level. One can envisage that the observed restructuring effects after topical application of the skin-care product are likely to ameliorate or restore the barrier function of the stratum corneum. In this, the properties of the emollient go beyond the cosmetic feel.

脂质链长度与特应性皮炎相关性研究进展

特应性皮炎(atopic dermatitis,AD)是一种慢性、复发性炎症性皮肤病。越来越多证据表明,皮肤屏障功能障碍是导致AD的重要原因。皮肤最外层的脂质基质角质层(stratum corneum,SC)对皮肤屏障功能的维系至关重要。大量研究显示,角质层脂质含量降低、链长度缩短、神经酰胺(ceramide,CER)亚类水平改变以及炎症反应等都会影响AD患者皮肤屏障功能。本文就角质层脂质链长度与AD患者皮肤屏障功能的关系做一综述。

深厚易塌孔地层灌注桩旋挖全套管钻沉拔一体施工技术

在深厚易塌孔地层进行旋挖灌注桩施工,通常需要沉入深长护筒进行护壁,以确保孔壁稳定。目前传统深长护筒的施工方法均需要2台或2台以上大型机械配合施工,工序复杂、钻进效率低。针对在深厚易塌孔地层超长护筒施工存在的问题,研发了一种灌注桩旋挖全套管钻、沉、拔一体施工技术,在沉入长护筒、旋挖取土、起拔长护筒全过程均只采用1台旋挖钻机进行施工,达到了施工工效高、成桩质量好、综合成本低的效果。

Study on the interaction between volatile oil components and skin lipids based on molecular docking techniques

Objective To analyze the interactions between different structural types of volatile oil compo-nents(VOCs)and skin lipid molecules;and investigate the mechanism of volatile oil in Chi-nese materia medica(VOCMM)as penetration enhancers.Methods In this study;210 different structural types of VOCs were selected from the VOCMM penetration enhancer database;and the molecular docking experiments were conducted with three main lipid molecules of skin:ceramide 2(CER2);cholesterol(CHL);and free fatty acid(FFA).Each VOC was docked individually with each lipid molecule.Cluster analysis was used to explore the relationship between the binding energy of VOCs and their molecular struc-tures.Nine specific pathogen-free(SPF)Sprague Dawley(SD)rats were randomly divided in-to Control;Nootkatone;and 3-Butylidenephthalide groups for in vitro percutaneous experi-ments;with three rats in each group.The donor pool solutions were 3%gastrodin;3%gas-trodin+3%nootkatone;and 3%gastrodin+3%3-butylidenephthalide;respectively.The pen-etration enhancing effects of VOCs with higher binding energy were evaluated by comparing the 12-hour cumulative percutaneous absorption of gastrodin(Q12;µg/cm²).Results(i)Most of the VOCs were non-hydrogen bonded to the hydrophobic parts of CHL and FFA;and hydrogen bonded to the head group of CER2.Among them;sesquiterpene ox-ides showed the most pronounced binding affinity to CER2.The VOCs with 2-4 rings(in-cluding carbon rings;benzene rings;and heterocycles)demonstrated stronger binding affini-ty for three skin lipid molecules compared with the VOCs without intramolecular rings(P<0.01).(ii)According to the cluster analysis;most of the VOCs that bond well to CER2 had 2-3 intramolecular rings.The non-oxygenated VOCs were bonded to CER2 in a hydrophobic manner.The oxygenated VOCs were mostly bonded to CER2 by hydrogen bonding.(iii)The results of Franz diffusion cell experiment showed that the Q12 of Control group was 260.60±25.09µg/cm2;and the transdermal absorption of gastrodin was significantly increased in Nootkatone group(Q12=5503.00±1080.00µg/cm²;P<0.01).The transdermal absorption of gastrodin was also increased in 3-Butylidenephthalide group(Q12=495.40±56.98µg/cm²;P>0.05).(iv)The type of oxygen-containing functional groups in VOCs was also an influencing factor of binding affinity to CER2.Conclusion The interactions between different types of VOCs with different structures in the VOCMM and three skin lipid molecules in the stratum corneum were investigated at the molecular level in this paper.This research provided theoretical guidance and data support for the screening of volatile oil-based penetration enhancers;and a simple and rapid method for studying the penetration-enhancing mechanism of volatile oils.

Supporting Skin Structure and Its Barrier Functions with Evidence-Based Skin Care Ingredients

The epidermis, and in particular its outermost layer, the stratum corneum, contributes much of the barrier function of the skin and is a readily visible representation of skin health. Maintaining the health of the skin barrier has arguably become more important than ever in the modern world, in which a large majority of people are exposed to environmental insults. These external factors can damage the integrity of the skin barrier and prematurely age the skin. Therefore, it has become increasingly important to maintain and protect the stratum corneum. Here, we briefly review the complex, multilayered structure of the skin and relate it to clinically translatable function, with an emphasis on the stratum corneum. In the context of epidermal structure and function, the formulation and clinical data for Phelityl® Reviving Cream will be reviewed. Phelityl Reviving Cream was shown to be associated with improvements in both immediate- and long-term parameters, including a significant positive effect on the skin barrier and immediate and long-lasting hydration.

美满霉素与异维A酸对痤疮患者血清TNF-α、hs-CRP、IL-6水平、角质层含水量的影响分析

目的:探讨美满霉素与异维A酸对痤疮患者血清炎性因子及角质层含水量(MCOC)的影响。方法:选取2019年9月—2021年6月尉氏县人民医院收治的127例面部痤疮患者作为研究对象,根据治疗方案不同将患者分为对照组(n=63)与研究组(n=64)。对照组患者采用异维A酸治疗,研究组患者采用美满霉素联合异维A酸治疗,两组患者均治疗6周。对比两组患者治疗前后MCOC、肿瘤坏死因子α(TNF-α)、经表皮失水量(TEWL)、白细胞介素6(IL-6)、角质层样本蛋白质含量、C-反应蛋白(hs-CRP)水平及不良反应。结果:治疗后,研究组患者的TEWL、角质层样本蛋白质水平低于对照组,MCOC水平高于对照组,差异有统计学意义(t=3.703、2.769、3.504,P<0.05);治疗后,研究组患者的TNF-α、hs-CRP、IL-6水平均低于对照组,差异有统计学意义(t=4.280、19.008、3.512,P<0.05);两组患者不良反应比较,差异无统计学意义(χ^(2)=0.401,P>0.05)。结论:美满霉素联合异维A酸治疗能够有效提高痤疮患者角质层含水量,降低血清TNF-α、hs-CRP、IL-6水平并改善患者皮损症状。

山茶花及灵芝精萃物保湿霜对人体皮肤微生态的影响

为探讨天然植物源提取物护肤品对人体皮肤微生态的影响,以山茶花及灵芝精萃物保湿霜为供试物,采用16S rRNA及ITS rRNA基因高通量测序方法,结合电容法测定皮肤角质层含水量,揭示了保湿霜使用前及使用后14 d和28 d时皮肤微生物群落多样性及种群结构的变化过程与内在原因。研究发现,山茶花及灵芝精萃物保湿霜的使用增加了皮肤细菌群落的多样性,但同时也降低了真菌种群的物种数量。D0、D14及D28组样本分别聚类在不同区域且具备明显区分度。两种保湿霜的使用未改变皮肤微生物在门水平上的群落构成,使用前后细菌及真菌优势门相同。在属水平上,山茶花及灵芝精萃物保湿霜的使用显著增加了细菌中葡萄球菌属和表皮杆状菌属的相对丰度,但真菌群落的相对丰度呈无序变化。此外,两种保湿霜的使用均大幅提升了皮肤角质层的水分含量。结果表明,山茶花及灵芝精萃物保湿霜具有补水保湿功效,可有效调节并改善皮肤菌群的微生态平衡。

一种油凝胶型手部磨砂膏的制备及功效评估

本研究制备了一种油凝胶型的手部磨砂膏,以聚氨基甲酸酯和蜡酯为增稠剂、悬浮剂,让磨砂粒子稳定悬浮在油凝胶体系中,从流变测试结果可知,该油凝胶具有黏弹性,为假塑性流体,具有剪切变稀的特性。体外鸡胚绒毛尿囊膜(CAM)刺激性测试中显示为轻刺激。在人体功效测试中,使用该手部磨砂膏15 min后测试手背皮肤角质层水分含量显著提升(P<0.05),经表皮水分流失率(TEWL)降低4.79%,皮肤粗糙度参数SEr值显著增加23.94%(P<0.05),说明该样品具有滋润、不损伤皮肤屏障、改善皮肤粗糙的功效。

城乡深度融合背景下农村社会阶层的“梯形”结构研究——以成都平原J村为例

城乡融合背景下农村的社会阶层结构是值得关注的问题。J村是成都平原城乡深度融合的代表,文章基于职业维度将J村村民划分为十大阶层,发现J村阶层结构呈现出以往农村中没有的“梯形”形态,这是城乡深度融合下从“金字塔形”向“橄榄形”过渡的中间形态。数据分析表明,J村村民收入差距较为悬殊,不同阶层内部存在不同的收入差距;阶层代内流动强,代际传递作用弱,与全国农村阶层相比较,J村阶层结构更合理。研究发现,土地流转促使J村阶层结构开始变迁,在改革政策的支持下,充分利用市场环境,发挥村落动能,在作为外部因素的政策牵引和市场环境的拉动作用,与作为内部因素的村集体动能和村民个体动能的推动作用下,内外因素相互作用,促成J村社会阶层结构良性变迁。文章首次提出农村社会阶层的“梯形”结构,可能丰富我国社会阶层结构的过渡形态。

软弱破碎岩层浅埋隧道地表注浆加固

以于都1号隧道工程项目为依托,在穿越地层断裂带、周边围岩松散、自稳定性能差、埋深约39~58 m、长度155 m软弱围岩段,研究软弱地层中浅埋隧道地表注浆加固技术措施,对注浆前后岩层进行取芯对比、超前钻探及掌子面地层揭示对比、地下水量对比等,表明地层加固效果良好。

Numerical Calculation of Channel Dredging Volume Using 3D Digital Stratum Model

Prediction of channel dredging volume is critical for project cost estimation. However, many proposed approximate methods are not accurate. This paper presents a novel numerical method to accurately calculate the dredg- ing volume using a 3D stratum model (DSM) and a channel surface model. First, the 3D DSM is constructed rapidly yet accurately from non-uniform rational B-splines (NURBS) surfaces through Boolean operation between a physical terrain model and a stratum surfaces model. Then, a parametric channel surface model is built from cross-section data and a channel center line using code implemented in the VC++ programming language. Finally, the volumes of different types of physical stratums can be calculated automatically and hierarchically to determine the dredging volume. Practical application shows that the DSM method is more precise and faster compared to the section method, and that the implementation of the developed software provides an interactive graphical user interface and visual presentation.

MECHANICAL ANALYSIS OF SHAFT LINING WHEN THE STRATUM SETTLEMENT RESULTING FROM WATER DRAINAGE

Based on the stratum settlement resulting from water drainage, this paper establishes the calculating method of stresses and displacements of shaft lining and stratum by using Fourier integration, obtains the calculating formulas of tangiential load which shaft lining is subjected to, and provides theoretical basis for design of shaft lining.

Numerical Simulation of Skin Formation: The Relationship between Transepidermal Water Loss and Corneum Thickness

Skin moisturizing has drawn attention in terms of beauty and anti-aging industries. However, it is difficult to observe the inside of the epidermis and the relationship between the epidermis and water content is not yet clear. Computational simulations can be useful in understanding such mechanisms of skin formation. A particle model was used to simulate three-dimensional skin turnover, and the results reproduced the epidermal skin turnover phenomenon. In this study, a diffusion model is introduced into this simulation model and a moisture diffusion analysis of the epidermis was performed. In particular, transepidermal water loss (TEWL) was modeled by considering diffusion and surface evaporation in the stratum corneum and other layers. The relationship between the moisture content and the keratin detachment was considered, and the exfoliation condition of keratin based on the moisture content was calculated in the model. As a result, it was possible to calculate the intraepidermal water content distribution in the skin using the particle model. It was also possible to reproduce phenomena such as keratin thickening due to increase of TEWL. This phenomenon is consistent with cases of dry skin. In the future, it will be necessary to introduce a change in TEWL according to the thickness of the stratum corneum and the diffusion coefficient.

慢性阻塞性肺病稳定期患者表皮功能改变及其临床意义

目的探讨肺部疾病患者与健康老人表皮生物物理特性是否存在差别。方法于2022年1月~3月收集50例慢性阻塞性肺病(COPD)老年患者和50例无肺病健康老年志愿者(61~91岁)。用GPSkin Barrier检测仪测量角质层含水量和经皮水分丢失率,用便携式酸碱度仪测量皮肤表面pH。结果(1)两组间面部、左臂和左腿的透皮水分丢失率无显著差异;(2)COPD患者左臂和左腿的角质层含水量显著降低(P<0.01),而面部角质层含水量无显著差异;(3)COPD患者左臂和左腿皮肤表面PH值显著高于无肺病者(P<0.01),但是面部皮肤表面pH无显著差异。结论COPD的老年患者皮肤衰老加速,表现为皮肤角质层含水量下降和皮肤pH值升高。对于COPD患者,修复表皮功能具有重要的临床意义。

表面活性剂与皮肤相互作用的研究进展

表面活性剂作为个人护理清洁产品的主要清洁成分,会直接接触皮肤进而与皮肤产生不同的作用。表面活性剂对皮肤的刺激性与其结构、类型、浓度、暴露时间、皮肤状态等多种因素相关。在清洁过程中,皮肤表面的污垢被表面活性剂增溶带入水中,表面活性剂也会与细胞间脂质相互作用加剧对皮肤屏障功能的破坏,导致皮肤干燥紧绷。但随着表面活性剂的进一步渗透并迁移到更深的皮层,会对活的表皮细胞如角质形成细胞产生破坏作用,并引起皮肤的局部炎症反应。文章简要概述了表面活性剂在水溶液中的基本性质及其结构与刺激性的联系,对表面活性剂的皮肤渗透理论模型、以及对皮肤脂质和活细胞的影响进行了归纳总结,并从个人护理产品配方角度出发,对表面活性剂降低皮肤刺激性的方法进行了可行性的展望。