Yes

Yes / Photobiomodulation-based (LLLT) therapies show tantalizing promise for treatment of skin diseases. Confidence in this approach is blighted however by lamentable inconsistency in published experimental designs, and so complicates interpretation. Here we interrogate the appropriateness of a range of previously-reported treatment parameters, including light wavelength, irradiance and radiant exposure, as well as cell culture conditions (e.g., serum concentration, cell confluency, medium refreshment, direct/indirect treatment, oxygen concentration, etc.), in primary cultures of normal human dermal fibroblasts exposed to visible and near infra-red (NIR) light. Apart from irradiance, all study parameters impacted significantly on fibroblast metabolic activity. Moreover, when cells were grown at atmospheric O2 levels (i.e. 20%) short wavelength light inhibited cell metabolism, while negligible effects were seen with long visible and NIR wavelength. By contrast, NIR stimulated cells when exposed to dermal tissue oxygen levels (approx. 2%). The impact of culture conditions was further seen when inhibitory effects of short wavelength light were reduced with increasing serum concentration and cell confluency. We conclude that a significant source of problematic interpretations in photobiomodulation reports derives from poor optimization of study design. Further development of this field using in vitro/ex vivo models should embrace significant standardization of study design, ideally within a design-of-experiment setting.

A study was conducted on the measurement of skin friction, the least under-stood component of drag. Skin friction is considered the "last frontier" in drag reduction for supersonic flight, but to understand skin friction, it must be accurately measured. This study utilized the direct measuring technique for skin friction. A small de-vice, termed a skin friction gage, measures the stress on a cantilever beam topped with a movable surface piece as a shear flow passes over the flush surface. The improvement of these devices for various flow fields is ongoing. A problem that arose with many designs was leakage of a gap-filling liquid. The typical direct measuring skin friction gage uses oil in a gap between the cantilever beam and the encasement to dampen vibrations, to create an even flow over the surface, and for temperature compensation. In high speed testing the oil leaks out; therefore, a gage with rubber to fill the gap instead of oil was introduced This study employed a finite element method model to fully understand the strains involved with the rubber and the skin friction gage. The development of a calibration device, called the Calibration Rig, for the rubber skin friction gages was constructed. The Calibration Rig was successful, but deemed to be more cumbersome than initially expected. This led to the development of a thin rubber sheet to cover the face of the gage instead of rubber filling the entire gap. More finite element method modeling was done to finalize the design of a gage with a rubber sheet. The design consisted of a plastic skin friction gage with an approximately 0.015 in. thick rubber sheet, a 0.0625 in. wide gap between the floating head on the cantilever beam and the encasement to be filled with oil, and semi-conductor strain gages to measure the beam deflection. Vibration tests were performed to determine if the rubber sheet produced the required damping. These tests were successful, and so much so, that the oil for damping was not necessary. However, supersonic wind tunnel tests at Mach 2.4 which were done at Virginia Polytechnic Institute and State University, initially yielded unfavorable results. The rubber sheet failed during the violent process of starting and unstarting of the tunnel. More study on the adhesive mounting of the rubber sheet to the skin friction gage face is needed. / Master of Science

Skin is a very broad topic that allows discovering and exploring all the possibilities of what skin can be. Furthermore, skin is much known for its flexibility that can shape and wrap almost every object we can think of. At the beginning of my thesis research about skin, I thought I knew enough about it to start, but I discovered later on that skin is not a surface. Moreover, I directed myself into exploring more and more about skin and its characteristics. I built many models to help me understand some of the natural identity of skin and related materials. Those models became a concept for my project - a museum of skin instruments - in Alexandria, Virginia where I implied the mechanism of different skin instruments in each building. Exploration and experiments were the key to develop my design process. / Master of Architecture

A thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, South Africa Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, South Africa Johannesburg 2017. / Psoriasis vulgaris is a chronic, hyper-proliferative skin condition which affects the patient’s quality of life. The treatment strategy involves long term use of drugs that maintain the condition, however; playing a pivotal negative role in patient compliance. A constructive development in the design of treatment addressing the disease should focus on the challenges faced by current designs. Hence, cellular internalization and trans-barrier transport of nanoparticles can be manipulated on the basis of the physicochemical and mechanical characteristics of nanoparticles to enhance the treatment options of the condition by reducing dosing and increasing the healing due to intracellular drug delivery. Dictating these characteristics allows for the control of the rate and extent of cellular uptake, as well as delivering the drug-loaded nanosystem intra-cellularly which is imperative for drugs that require a specific cellular level to exert their effects, as is with psoriasis. Additionally, physicochemical characteristics of the nanoparticles should be optimal for the nanosystem to bypass the natural restricting phenomena of the body and act therapeutically at the targeted site. Neo-geometric copper nanoparticles (CuNPs) in the biomedical application ascertained skin permeation and retention of the CuNPs as a drug delivery system. The approach to the use of the nanocrystal exploited the shape properties as a function of enhanced cellular uptake and the copper in the inflamed psoriatic environment acted as a cytotoxic agent against hyper-proliferating keratinocytes. A Self-Oscillating Polymeric Network (SOPN) served as a vehicle for the topical delivery of the geometric CuNPs in addition to its oscillating phenomenon to promote the permeation of the active nanoparticles across the rate limiting barrier of the skin, the stratum corneum. This twofold system adequately targets the key limitations in addressing psoriasis. A statistical experimental design comprising a full factorial model for the optimization of the geometric CuNPs and Box-Behnken design applied on the SOPN served as a refining factor to achieve stable, homogenous, geometric nanoparticles using a one-pot method for the systematic optimization of the geometric CuNPs. The optimization of the SOPN involved amplitude and duration of the oscillations, permeation kinetics and cytotoxicity. After optimization of the nano-shapes and oscillations of the SOPN, extensive ex vivo cellular internalization studies were conducted to elucidate the effect of geometric CuNPs on uptake rates; in addition to the vital toxicity assays to further understand the cellular effect of geometric CuNPs as a drug delivery system. Complementing the geometry analysis; volume, surface area, orientation to the cell membrane and colloidal stability were also addressed. The SOPN was also investigated ex vivo for its biocompatibility to determine the LD50 and permeation kinetics. The in vivo study probed the nanosystem embedded in the innovative SOPN to stimulate the permeation of the CuNPs across the stratum corneum of the induced psoriasiform-plaque in a BALB/c mouse model. The results confirmed an optimized CuNPs-loaded SOPN topical system with promising plaque thickness reduction when compared with a commercial gold standard in the treatment of the skin condition. This novel system can be safely used with less frequent, lower dosing and no odour, therefore promoting patient compliance. / MT2017

Ping-kuen Lam. / "May 1998." / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 109-121). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

To date, the reconstructive approach addressing chronic non-healing wounds, deep tissue damage, and severe wound defects relies upon avascular dermal grafts and autologous flap techniques. Such flaps are limited by donor site availability and morbidity, while current dermal grafts rely upon host cellular invasion for neovascularization and incorporation. These products fail to include an inherent vascular network and the supporting cells necessary to ensure adequate incorporation and graft survival beyond the most optimal wound beds. Herein, we fabricate a pre-vascularized full-thickness cellularized skin equivalent containing a three-dimensional vascularized network of interconnected macro and microchannels lined with vascular cells, within a collagen neodermis populated with fibroblasts, and an epidermis comprised of human keratinocytes capable of providing whole tissue perfusion. Previously, our lab has employed a sacrificial microfiber technique to develop tissue-engineered scaffolds with an inherent hierarchical network of microvessels, which recapitulates the organization of an arteriole, venule, and capillary bed. Utilizing a type-I collagen hydrogel matrix, vascular cells were seeded within pre-fabricated channels and allowed to proliferate to generate an endothelialized microvasculature. These collagen scaffolds were subsequently anastomosed into rat models to demonstrate the clinical feasibility of such approach. The present study aims to more closely recapitulate the in vivo structure of human skin via the incorporation of vital epidermal and dermal components of native skin into a biocompatible construct containing a complex hierarchical vasculature, which may be anastomosed using standard microsurgical techniques and immediately perfused. Pluronic F127 was used as the sacrificial material: 1.5 mm diameter “U” shaped macrofibers and 100-500 µm-interwoven microfibers were heat extruded and then embedded within type-I collagen into which Cyan Fluorescent Protein (CFP)-tagged human placental pericytes and human foreskin fibroblasts (HFF1) had been encapsulated. Following pluronic sacrifice, resultant channels were intraluminally seeded with Red Fluorescent Protein (RFP)-tagged human aortic smooth muscle cells, Green Fluorescent Protein (GFP)-tagged human umbilical vein endothelial cells, and topically seeded with human epidermal keratinocytes (HEK). Construct microstructure was analyzed using multiphoton microscopy (MPM) after 7, 14 and 28 days of culture. Additionally, after 14 and 28 days of culture, endothelial cells were extracted from the construct using collagenase digestion and Real Time (RT)-qPCR performed to analyze expression of markers of angiogenesis and maturation of the vascular network. MPM demonstrated a hierarchical vascular network containing macro and microvessels lined by endothelial and smooth muscle cells, supported by perivascular pericytes, all in appropriate microanatomic arrangement. Neodermal HFF1 proliferated throughout the observation period and the HEK neoepidermis developed into a stratified epidermis along the superior aspect of the construct. Angiogenic sprouting from the nascent vascular network into neovessel like structures was noted. RT- qPCR revealed relative expression of Jagged1, Dll4, Ve-Cadherin, and CD31. We have successfully fabricated a novel tissue-engineered pre-vascularized full thickness skin flap, which recapitulates the inherent hierarchical vasculature found within human skin and is suitable for in vivo perfusion. We provide the platform for an on- demand, geometrically tunable tissue engineered skin equivalent with an anastomosable vascular network. This tissue-engineered skin flap holds the potential to transform reconstructive surgical practice by eliminating the consequences of donor site morbidity, and enabling rationally designed, patient-specific flaps for each unique wound environment and anatomic location. / 2017-06-16T00:00:00Z

"May 2004" / Bibliography: leaves 172-184. / xvi, 186 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Nurs.)--University of Adelaide, Dept. of Clinical Nursing, 2004

Schwann cells are the glial cells of the peripheral nervous system. When transplanted into the injured central or peripheral nervous systems they promote repair. Traditionally Schwann cells have been isolated from the sciatic nerve, creating nerve-SC. An alternative Schwann cell source is from the differentiation of skin-derived precursors (SKPs), stem cells found in the skin, to Schwann cells (SKP-SC). SKP-SC have shown enhanced regenerative ability compared to nerve-SC. This study compares nerve-SC with SKP-SC at the functional and gene expression level to determine their degree of similarity and find their sources of variance. The functional ability of both Schwann cell types appeared similar. Their gene expression, as assessed by microarray, was similar but not identical. Genes that differed between nerve-SC and SKP-SC may represent differences important to regeneration. The similarity of SKP-SC to nerve-SC supports the use of SKP-SC for repair, and reasons for enhanced regeneration by SKP-SC are suggested.

Schwann cells are the glial cells of the peripheral nervous system. When transplanted into the injured central or peripheral nervous systems they promote repair. Traditionally Schwann cells have been isolated from the sciatic nerve, creating nerve-SC. An alternative Schwann cell source is from the differentiation of skin-derived precursors (SKPs), stem cells found in the skin, to Schwann cells (SKP-SC). SKP-SC have shown enhanced regenerative ability compared to nerve-SC. This study compares nerve-SC with SKP-SC at the functional and gene expression level to determine their degree of similarity and find their sources of variance. The functional ability of both Schwann cell types appeared similar. Their gene expression, as assessed by microarray, was similar but not identical. Genes that differed between nerve-SC and SKP-SC may represent differences important to regeneration. The similarity of SKP-SC to nerve-SC supports the use of SKP-SC for repair, and reasons for enhanced regeneration by SKP-SC are suggested.