Production of continuous piezoelectric ceramic fibers for smart materials and active control devices

NASA Astrophysics Data System (ADS)

French, Jonathan D.; Weitz, Gregory E.; Luke, John E.; Cass, Richard B.; Jadidian, Bahram; Bhargava, Parag; Safari, Ahmad

1997-05-01

Advanced Cerametrics Inc. has conceived of and developed the Viscous-Suspension-Spinning Process (VSSP) to produce continuous fine filaments of nearly any powdered ceramic materials. VSSP lead zirconate titanate (PZT) fiber tows with 100 and 790 filaments have been spun in continuous lengths exceeding 1700 meters. Sintered PZT filaments typically are 10 - 25 microns in diameter and have moderate flexibility. Prior to carrier burnout and sintering, VSSP PZT fibers can be formed into 2D and 3D shapes using conventional textile and composite forming processes. While the extension of PZT is on the order of 20 microns per linear inch, a woven, wound or braided structure can contain very long lengths of PZT fiber and generate comparatively large output strokes from relatively small volumes. These structures are intended for applications such as bipolar actuators for fiber optic assembly and repair, vibration and noise damping for aircraft, rotorcraft, automobiles and home applications, vibration generators and ultrasonic transducers for medical and industrial imaging. Fiber and component cost savings over current technologies, such as the `dice-and-fill' method for transducer production, and the range of unique structures possible with continuous VSSP PZT fiber are discussed. Recent results have yielded 1-3 type composites (25 vol% PZT) with d33 equals 340 pC/N, K equals 470, and g33 equals 80 mV/N, kt equals 0.54, kp equals 0.19, dh equals 50.1pC/N and gh equals 13 mV/N.

Human neutrophil elastase and collagenase sequestration with phosphorylated cotton wound dressings.

PubMed

Edwards, J Vincent; Howley, Phyllis S

2007-11-01

The design and preparation of wound dressings that redress the protease imbalance in chronic wounds is an important goal of wound healing and medical materials science. Chronic wounds contain high levels of tissue and cytokine-destroying proteases including matrix metalloprotease and neutrophil elastase. Thus, the lowering of excessive protease levels in the wound environment by wound dressing sequestration prevents the breakdown of extracellular matrix proteins and growth factors necessary for wound healing. Phosphorylated cotton wound dressings were prepared to target sequestration of proteases from chronic wound exudate through a cationic uptake binding mechanism involving salt bridge formation of the positively charged amino acid side chains of proteases with the phosphate counterions of the wound dressing fiber. Dressings were prepared by applying sodium hexametaphosphate and diammonium phosphate in separate formulations to cotton gauze by pad/dry/cure methods. Phosphorylated cotton dressings were assessed for their ability to lower elastase and collagenase activity. The phosphorylated cotton dressings lowered elastase and collagenase activity 40-80% more effectively than the untreated cotton wound dressings under conditions that mimic chronic wound exudate. Efficacy of the phosphorylated cotton was found to be related to the level of phosphorylation and a lower pH due to protonated phosphate at the surface of the dressing. The capacity of the modified gauze to sequester continued elastase secretions similar to that found in a chronic wound over a 24-h period was retained within a 80% retention of elastase sequestration and was dose-dependent. Copyright (c) 2007 Wiley Periodicals, Inc.

Distributed Sensing of Carbon-Epoxy Composites and Filament Wound Pressure Vessels Using Fiber-Bragg Gratings

NASA Technical Reports Server (NTRS)

Grant, J.; Kaul, R.; Taylor, S.; Myer, G.; Jackson, K.; Osei, A.; Sharma, A.

2003-01-01

Multiple Fiber Bragg-gratings are embedded in carbon-epoxy laminates as well as in composite wound pressure vessel. Structural properties of such composites are investigated. The measurements include stress-strain relation in laminates and Poisson's ratio in several specimens with varying orientation of the optical fiber Bragg-sensor with respect to the carbon fiber in an epoxy matrix. Additionally, fiber Bragg gratings are bonded on the surface of these laminates and cylinders fabricated out of carbon-epoxy composites and multiple points are monitored and compared for strain measurements at several locations.

Design, Preparation and Activity of Cotton Gauze for Use in Chronic Wound Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, J. V.; Yager, Dorne; Bopp, Alvin

We consider the rational design and chemical modification of cotton gauze, which is used widely in chronic wounds, to improve wound dressing fibers for application to chronic wound healing. Cotton gauze may be tailored to more effectively enhance the biochemistry of wound healing. The presence of elevated levels of elastase in non-healing wounds has been associated with the degradation of important growth factors and fibronectin necessary for wound healing. In the healing wound a balance of elastase and antiproteases precludes degradation of beneficial proteins from taking place. Cotton gauze modified to release elastase inhibitors or selectively functionalized to sequester elastasemore » provides a dressing that decreases high levels of destructive elastase in the chronic wounds. Three approaches have been taken to explore the potential of fiber-inhibitors useful in chronic wounds: 1) Formulation of inhibitors on the dressing; 2) Synthesis of elastase recognition sequences on cotton cellulose; and 3) Data presented here on carboxymethylating, and oxidizing textile finishes of cotton gauze to remove elastase from the wound.« less

Comparison of hand laid-up tape and filament wound composite cylinders and panels with and without impact damage

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Lopez, Osvaldo F.

1991-01-01

Experimentally determined axial compressive failure loads, strains and failure modes of composite flat panels and cylinders are presented. A comparison of two types of filament wound flat graphite-epoxy panels indicates that the winding pattern can influence structural response. A comparison of hand laid-up tape and filament wound composite cylinders indicates that fabrication method may not significantly influence the failure mode or average failure strain of thick-walled (radius-to-thickness ratio less than 15) graphite-epoxy cylinders. The interaction of manufacturing-induced features (fiber cross-overs) and low-speed impact damage for graphite-epoxy specimens is also presented. Filament would flat panels with many fiber cross-overs exhibited lower failure strains than filament wound panels without fiber cross-overs for all impact speeds examined. Graphite-thermoplastic cylinders exhibited a significantly different failure mode from the graphite-epoxy cylinders.

Investigation of Electrospun Poly Vinyl Alcohol Fibers Towards the Development of Manufacturable Wound Dressings

NASA Astrophysics Data System (ADS)

Vora, Asad

Polymers such as polyvinyl alcohol, chitosan, and starch have excellent bio-compatible and bio-degradable properties. Their applications in drug delivery, wound dressings, artificial cartilage materials have increased dramatically due to their much sought-after renewable and biological properties. Hence, polyvinyl alcohol has been chosen for this study to test the feasibility of polyvinyl alcohol nanofibers towards the manufacturable wound dressings. Polyvinyl alcohol nanofibers are prepared via electrospinning technique, where different wt% polyvinyl alcohol solutions are prepared. The fibers were optimized by varying important electrospninning parameters which include voltage applied, the collector-needle distance and flow rate. Morphology and structure of the electrospun fibers are analysed using scanning electron microscopy and fourier transform infrared respectively. The diameter of fibers obtained was found to be in the range of 100 nm-160 nm. Thermal stability was examined using DSC and TGA characterization technique and fibers are found to be stable up to 220oC. Finally, each weight sample of PVA fibers are analysed by goniometer for wettability and is found to be hydrophilic.

Wound dressings composed of copper-doped borate bioactive glass microfibers stimulate angiogenesis and heal full-thickness skin defects in a rodent model.

PubMed

Zhao, Shichang; Li, Le; Wang, Hui; Zhang, Yadong; Cheng, Xiangguo; Zhou, Nai; Rahaman, Mohamed N; Liu, Zhongtang; Huang, Wenhai; Zhang, Changqing

2015-01-01

There is a need for better wound dressings that possess the requisite angiogenic capacity for rapid in situ healing of full-thickness skin wounds. Borate bioactive glass microfibers are showing a remarkable ability to heal soft tissue wounds but little is known about the process and mechanisms of healing. In the present study, wound dressings composed of borate bioactive glass microfibers (diameter = 0.4-1.2 μm; composition 6Na2O, 8K2O, 8MgO, 22CaO, 54B2O3, 2P2O5; mol%) doped with 0-3.0 wt.% CuO were created and evaluated in vitro and in vivo. When immersed in simulated body fluid, the fibers degraded and converted to hydroxyapatite within ∼7 days, releasing ions such as Ca, B and Cu into the medium. In vitro cell culture showed that the ionic dissolution product of the fibers was not toxic to human umbilical vein endothelial cells (HUVECs) and fibroblasts, promoted HUVEC migration, tubule formation and secretion of vascular endothelial growth factor (VEGF), and stimulated the expression of angiogenic-related genes of the fibroblasts. When used to treat full-thickness skin defects in rodents, the Cu-doped fibers (3.0 wt.% CuO) showed a significantly better capacity to stimulate angiogenesis than the undoped fibers and the untreated defects (control) at 7 and 14 days post-surgery. The defects treated with the Cu-doped and undoped fibers showed improved collagen deposition, maturity and orientation when compared to the untreated defects, the improvement shown by the Cu-doped fibers was not markedly better than the undoped fibers at 14 days post-surgery. These results indicate that the Cu-doped borate glass microfibers have a promising capacity to stimulate angiogenesis and heal full-thickness skin defects. They also provide valuable data for understanding the role of the microfibers in healing soft tissue wounds. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chromatographic and traditional albumin isotherms on cellulose: a model for wound protein adsorption on modified cotton

USDA-ARS?s Scientific Manuscript database

Albumin is the most abundant protein found in healing wounds. Traditional and chromatogrpahic protein isotherms of albumin binding on modified cotton fibers are useful in understanding albumin binding to cellulose wound dressings. An important consideration in the design of cellulosic wound dressin...

Method for Coating a Tow with an Electrospun Nanofiber

NASA Technical Reports Server (NTRS)

Kohlman, Lee W. (Inventor); Roberts, Gary D. (Inventor)

2015-01-01

Method and apparatus for enhancing the durability as well as the strength and stiffness of prepreg fiber tows of the sort used in composite materials are disclosed. The method involves adhering electrospun fibers onto the surface of such composite materials as filament-wound composite objects and the surface of prepreg fiber tows of the sort that are subsequently used in the production of composite materials of the filament-wound, woven, and braided sorts. The apparatus performs the methods described herein.

Peptide-Modified Chitosan Hydrogels Accelerate Skin Wound Healing by Promoting Fibroblast Proliferation, Migration, and Secretion

PubMed Central

Chen, Xionglin; Zhang, Min; Chen, Shixuan; Wang, Xueer; Tian, Zhihui; Chen, Yinghua; Xu, Pengcheng; Zhang, Lei

2017-01-01

Skin wound healing is a complicated process that involves a variety of cells and cytokines. Fibroblasts play an important role in this process and participate in transformation into myofibroblasts, the synthesis of extracellular matrix (ECM) and fibers, and the secretion of a variety of growth factors. This study assessed the effects of peptide Ser-Ile-Lys-Val-Ala-Val (SIKVAV)--modified chitosan hydrogels on skin wound healing. We investigated the capability of peptide SIKVAV to promote cell proliferation and migration, the synthesis of collagen, and the secretion of a variety of growth factors using fibroblasts in vitro. We also treated skin wounds established in mice using peptide SIKVAV-modified chitosan hydrogels. Hematoxylin and eosin staining showed that peptide-modified chitosan hydrogels enhanced the reepithelialization of wounds compared with negative and positive controls. Masson’s trichrome staining demonstrated that more collagen fibers were deposited in the wounds treated with peptide-modified chitosan hydrogels compared with the negative and positive controls. Immunohistochemistry revealed that the peptide-modified chitosan hydrogels promoted angiogenesis in the skin wound. Taken together, these results suggest that peptide SIKVAV-modified chitosan hydrogels may be useful in wound dressing and the treatment of skin wounds. PMID:28901187

Activin B regulates adipose-derived mesenchymal stem cells to promote skin wound healing via activation of the MAPK signaling pathway.

PubMed

Zhang, Lei; Xu, Pengcheng; Wang, Xueer; Zhang, Min; Yan, Yuan; Chen, Yinghua; Zhang, Lu; Zhang, Lin

2017-06-01

Adipose-derived stem cells (ADSCs) are multipotent stromal cells that can differentiate into a variety of cell types, including skin cells, and they can provide an abundant source of cells for skin tissue engineering and skin wound healing. The purpose of this study is to explore the therapeutic effects of activin B in combination with ADSCs and the possible signaling mechanism. In this study, we found that activin B was able to promote ADSC migration by inducing actin stress fiber formation in vitro. In vivo, activin B in combination with ADSCs was capable of enhancing α-SMA expression and wound closure. This combined treatment also promoted fibroblast and keratinocyte proliferation and accelerated re-epithelialization and collagen deposition. Moreover, activin B in combination with ADSCs boosted angiogenesis in the wound area. Further study of the mechanism revealed that activation of JNK and ERK signaling, but not p38 signaling, were required for activin B-induced ADSC actin stress fiber formation and cell migration. These results showed that activin B was able to activate JNK and ERK signaling pathways to induce actin stress fiber formation and ADSC migration to promote wound healing. These results suggest that combined treatment with activin B and ADSCs is a promising therapeutic strategy for the management of serious skin wounds. Copyright © 2017. Published by Elsevier Ltd.

Topical fentanyl stimulates healing of ischemic wounds in diabetic rats

PubMed Central

FAROOQUI, Mariya; ERICSON, Marna E; GUPTA, Kalpna

2016-01-01

Background Topically applied opioids promote angiogenesis and healing of ischemic wounds in rats. We examined if topical fentanyl stimulates wound healing in diabetic rats by stimulating growth-promoting signaling, angiogenesis, lymphangiogenesis and nerve regeneration. Methods We used Zucker diabetic fatty rats that develop obesity and diabetes on a high fat diet due to a mutation in the Leptin receptor. Fentanyl blended with hydrocream was applied topically on ischemic wounds twice daily, and wound closure was analyzed regularly. Wound histology was analyzed by hematoxylin and eosin staining. Angiogenesis, lymphangiogenesis, nerve fibers and phospho-PDGFR-β were visualized by CD31-, lymphatic vessel endothelium-1, protein gene product 9.5- and anti-phospho PDGFR-β-immunoreactivity, respectively. Nitric oxide synthase (NOS) and PDGFR-β signaling were analyzed using Western immunoblotting. Results Fentanyl significantly promoted wound closure as compared to PBS. Histology scores were significantly higher in fentanyl-treated wounds, indicative of increased granulation tissue formation, reduced edema and inflammation, and increased matrix deposition. Fentanyl treatment resulted in increased wound angiogenesis, lymphatic vasculature, nerve fibers, nitric oxide, NOS and PDGFR-β signaling as compared to PBS. Phospho PDGFR-β co-localized with CD31 co-staining for vasculature. Conclusions Topically applied fentanyl promotes closure of ischemic wounds in diabetic rats. Increased angiogenesis, lymphangiogenesis, peripheral nerve regeneration, NO and PDGFR-β signaling are associated with fentanyl-induced tissue remodeling and wound healing. PMID:25266258

Schinus terebinthifolius Raddi ( Aroeira) leaves oil attenuates inflammatory responses in cutaneous wound healing in mice 1.

PubMed

Estevão, Lígia Reis Moura; Simões, Ricardo Santos; Cassini-Vieira, Puebla; Canesso, Maria Cecilia Campos; Barcelos, Lucíola da Silva; Rachid, Milene Alvarenga; Câmara, Cláudio Augusto Gomes da; Evêncio-Neto, Joaquim

2017-09-01

To investigated the inflammatory, angiogenic and fibrogenic activities of the Schinus terebinthifolius Raddi leaves oil (STRO) on wound healing. The excisional wound healing model was used to evaluate the effects of STRO. The mice were divided into two groups: Control, subjected to vehicle solution (ointment lanolin/vaseline base), or STRO- treated group, administered topically once a day for 3, 7 and 14 days post-excision. We evaluated the macroscopic wound closure rate; the inflammation was evaluated by leukocytes accumulation and cytokine levels in the wounds. The accumulation of neutrophil and macrophages in the wounds were determined by assaying myeloperoxidase and N-acetyl-β-D-glucosaminidase activities. The levels of TNF-α, CXCL-1 and CCL-2 in wound were evaluated by ELISA assay. Angiogenesis and collagen fibers deposition were evaluated histologically. We observed that macroscopic wound closure rate was improved in wounds from STRO-group than Control-group. The wounds treated with STRO promoted a reduction in leucocyte accumulation and in pro-inflammatory cytokine. Moreover, STRO treatment increased significantly the number of blood vessels and collagen fibers deposition, as compared to control group. Topical application of STRO display anti-inflammatory and angiogenic effects, as well as improvement in collagen replacement, suggesting a putative use of this herb for the development of phytomedicines to treat inflammatory diseases, including wound healing.

Aging results for PRD 49 III/epoxy and Kevlar 49/epoxy composite pressure vessels

NASA Technical Reports Server (NTRS)

Hamstad, M. A.

1983-01-01

Kevlar 49/epoxy composite is growing in use as a structural material because of its high strength-to-weight ratio. Currently, it is used for the Trident rocket motor case and for various pressure vessels on the Space Shuttle. In 1979, the initial results for aging of filament-wound cylindrical pressure vessels which were manufactured with preproduction Kevlar 49 (Hamstad, 1979) were published. This preproduction fiber was called PRD 49 III. This report updates the continuing study to 10-year data and also presents 7.5-year data for spherical pressure vessels wound with production Kevlar 49. For completeness, this report will again describe the specimens of the original study with PRD 49 as well as specimens for the new study with Kevlar 49.

Dynamic multiphoton imaging of acellular dermal matrix scaffolds seeded with mesenchymal stem cells in diabetic wound healing.

PubMed

Chu, Jing; Shi, Panpan; Deng, Xiaoyuan; Jin, Ying; Liu, Hao; Chen, Maosheng; Han, Xue; Liu, Hanping

2018-03-25

Significantly effective therapies need to be developed for chronic nonhealing diabetic wounds. In this work, the topical transplantation of mesenchymal stem cell (MSC) seeded on an acellular dermal matrix (ADM) scaffold is proposed as a novel therapeutic strategy for diabetic cutaneous wound healing. GFP-labeled MSCs were cocultured with an ADM scaffold that was decellularized from normal mouse skin. These cultures were subsequently transplanted as a whole into the full-thickness cutaneous wound site in streptozotocin-induced diabetic mice. Wounds treated with MSC-ADM demonstrated an increased percentage of wound closure. The treatment of MSC-ADM also greatly increased angiogenesis and rapidly completed the reepithelialization of newly formed skin on diabetic mice. More importantly, multiphoton microscopy was used for the intravital and dynamic monitoring of collagen type I (Col-I) fibers synthesis via second harmonic generation imaging. The synthesis of Col-I fibers during diabetic wound healing is of great significance for revealing wound repair mechanisms. In addition, the activity of GFP-labeled MSCs during wound healing was simultaneously traced via two-photon excitation fluorescence imaging. Our research offers a novel advanced nonlinear optical imaging method for monitoring the diabetic wound healing process while the ADM and MSCs interact in situ. Schematic of dynamic imaging of ADM scaffolds seeded with mesenchymal stem cells in diabetic wound healing using multiphoton microscopy. PMT, photo-multiplier tube. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Filament-wound graphite/epoxy rocket motor case

NASA Technical Reports Server (NTRS)

Humphrey, W. D.; Schmidt, W. W.

1972-01-01

The fabrication procedures are described for a filament-wound rocket motor case, approximately 56 cm long x 71 cm diameter, utilizing high tensile strength graphite fibers. The process utilized Fiberite Hy-E-1330B prepreg tape which consists of Courtaulds HTS fibers in a temperature-sensitive epoxy matrix. This fabrication effort, with resultant design, material and process recommendations, substantiates the manufacturing feasibility of graphite/epoxy rocket motor cases in the 56 cm x 71 cm size range.

In vitro study of improved wound-healing effect of bioactive borate-based glass nano-/micro-fibers.

PubMed

Yang, Qingbo; Chen, Sisi; Shi, Honglan; Xiao, Hai; Ma, Yinfa

2015-10-01

Because of the promising wound-healing capability, bioactive glasses have been considered as one of the next generation hard- and soft-tissue regeneration materials. The lack of understanding of the substantial mechanisms, however, indicates the need for further study on cell-glass interactions to better interpret the rehabilitation capability. In the present work, three bioactive glass nano-/micro-fibers, silicate-based 45S5, borate-based 13-93B3 and 1605 (additionally doped with copper oxide and zinc oxide), were firstly compared for their in vitro soaking/conversion rate. The results of elemental monitoring and electron microscopic characterization demonstrated that quicker ion releasing and glass conversion occurred in borate-based fibers than that of silicate-based one. This result was also reflected by the formation speed of hydroxyapatite (HA). This process was further correlated with original boron content and surrounding rheological condition. We showed that an optimal fiber pre-soaking time (or an ideal dynamic flow rate) should exist to stimulate the best cell proliferation and migration ability. Moreover, 13-93B3 and 1605 fibers showed different glass conversion and biocompatibility properties as well, indicating that trace amount variation in composition can also influence fiber's bioactivity. In sum, our in vitro rheological module closely simulated in vivo niche environment and proved a potentially improved wound-healing effect by borate-based glass fibers, and the results shall cast light on future improvement in bioactive glass fabrication. Copyright © 2015 Elsevier B.V. All rights reserved.

Hybrid Wound Filaments for Greater Resistance to Impacts

NASA Technical Reports Server (NTRS)

DeLay, Thomas K.; Patterson, James E.; Olson, Michael A.

2008-01-01

A hybrid material containing wound filaments made of a hybrid of high-strength carbon fibers and poly(phenylene benzobisoxazole) [PBO] fibers is discussed. This hybrid material is chosen in an effort to increase the ability of the pressure vessel to resist damage by low-speed impacts (e.g., dropping of tools on the vessel or bumping of the vessel against hard objects during installation and use) without significantly increasing the weight of the vessel. While the basic concept of hybridizing fibers in filament-wound structures is not new, the use of hybridization to increase resistance to impacts is an innovation, and can be expected to be of interest in the composite-pressure-vessel industry. The precise types and the proportions of the high-strength carbon fibers and the PBO fibers in the hybrid are chosen, along with the filament-winding pattern, to maximize the advantageous effects and minimize the disadvantageous effects of each material. In particular, one seeks to (1) take advantage of the ability of the carbon fibers to resist stress rupture while minimizing their contribution to vulnerability of the vessel to impact damage and (2) take advantage of the toughness of the PBO fibers while minimizing their contribution to vulnerability of the vessel to stress rupture. Experiments on prototype vessels fabricated according to this concept have shown promising results. At the time of reporting the information for this article, research toward understanding and optimizing the performances of PBO fibers so as to minimize their contribution to vulnerability of the pressure vessel to stress rupture had yet to be performed.

The role of bone marrow mesenchymal stromal cell derivatives in skin wound healing in diabetic mice.

PubMed

de Mayo, Tomas; Conget, Paulette; Becerra-Bayona, Silvia; Sossa, Claudia L; Galvis, Virgilio; Arango-Rodríguez, Martha L

2017-01-01

Mesenchymal stromal cells (MSCs) have shown to be a promising tool in cell therapies to treat different conditions. Several pre-clinical and clinical studies have proved that the transplantation of MSCs improves wound healing. Here, we compare the beneficial effects of mouse bone marrow-derived allogeneic MSCs (allo-mBM-MSCs) and their acelullar derivatives (allo-acd-mMSCs) on skin wound healing in Non-Obese Diabetic (NOD) mice. One dose of allo-mBM-MSCs (1×106 cells) or one dose of allo-acd-mMSCs (1X) were intradermally injected around wounds in 8-10 week old female NOD mice. Wound healing was evaluated macroscopically (wound closure) every two days, and microscopically (reepithelialization, dermoepidermal junction, skin appendage regeneration, leukocyte infiltration, vascularization, granulation tissue formation, and density of collagen fibers in the dermis) after 16 days of MSC injection. In addition, we measured growth factors and specific proteins that were present in the allo-acd-mMSCs. Results showed significant differences in the wound healing kinetics of lesions that received allo-acd-mMSCs compared to lesions that received vehicle or allo-mBM-MSCs. In particular, mice treated with allo-acd-mMSCs reached significantly higher percentages of wound closure at day 4, 6 and 8, relative to the allo-mBM-MSCs and vehicle groups (p < 0.05), while wound closure percentages could not be statistically distinguished between the allo-mBM-MSCs and vehicle groups. Also, allo-acd-mMSCs had a greater influence in the skin would healing process. Specifically, they caused a less pronounced inflammatory severe response (p < 0.0001), more granulation tissue formation at an advanced stage (p < 0.0001), and higher density of collagen fibers (p < 0.05) compared to the other groups. Nevertheless, at day 16, both allo-mBM-MSCs and allo-acd-mMSCs revealed a higher effect on the recovery of the quality skin (continuous epidermis; regular dermoepidermal junction and skin appendages) relative to untreated lesions (p < 0.0001), but not between them. On the other hand, ELISA analyses indicated that the allo-acd-mMSCs contained growth factors and proteins relevant to wound healing such as IGF-1, KGF, HGF, VEGF, ANG-2, MMP-1, CoL-1 and PGE2. Compared to allo-acd-mMSCs, the administration of allo-mBM-MSCs is insufficient for wound healing in diabetic mice and delays the therapeutic effect, which maybe explained by the fact that trophic factors secreted by MSCs are critical for skin regeneration, and not the cells per se, suggesting that MSCs may require some time to secrete these factors after their administration.

Test equipment data package for the KC-135 fiber pulling apparatus

NASA Technical Reports Server (NTRS)

Kosten, Sue; Smith, Guy A.; Workman, Gary; Tucker, Dennis

1991-01-01

The Fiber Pulling Apparatus (FPA) is a device designed to produce continuous glass fibers from simulated lunar soil, and to determine the effects of reduced gravity, specifically 1/6 g on fiber formation and resultant properties. Briefly, pre-melt simulated lunar soil will be placed in a pint crucible and heated to 1200 C or higher, up to a maximum temperature of 1400 C. At a given temperature, a quartz fiber will be immersed into the melt and then pulled through a chill block and wound onto a cylindrical bobbin using a servo motor control. A high resolution video camera will record the fiber as it is being pulled. This assembly wil be enclosed in Plexiglas. Before fiber pulling commences, the apparatus will be backfilled with dry nitrogen. A separate data acquisition system will support this apparatus. This system will contain a personal computer, video recorder, and monitor. Temperature, acceleration, winding speed, and video images will be controlled and recorded using the data acquisition system. Thus, the FPA will consist of two hardware packages, the fiber production assembly and the data acquisition rack. The primary objective of this test is to determine the effects of 1/6 g on the formation of continuous glass fiber made from simulated lunar soil. Baseline studies using the FPA on the ground will provide a reference for the 1/6 g studies. Of particular interest will be the effect of 1/6 g on the free fluid zone where the fiber exits the crucible. In the fiber spinning parlance this zone is known as the upper jet region, where the boundary slope is greater than one tenth. The properties of the resulting glass fiber will depend on the jet shape as well as distributions of velocity, temperature and tension within the jet. It is unknown at this time how 1/6 g will effect these parameters.

CVD apparatus and process for the preparation of fiber-reinforced ceramic composites

DOEpatents

Caputo, A.J.; Devore, C.E.; Lowden, R.A.; Moeller, H.H.

1990-01-23

An apparatus and process for the chemical vapor deposition of a matrix into a preform having circumferentially wound ceramic fibers, comprises heating one surface of the preform while cooling the other surface thereof. The resulting product may have fibers that are wound on radial planes or at an angle from the radial planes. The fibers can also be precoated with pyrolytic carbon before application of the matrix. The matrix is applied by passing reactant gas through the preform thereof to the other side thereof for the initial deposition of matrix near such other surface of the preform. The matrix fills in the preform from the other side surface thereof to the surface of the side of application thereof until a desired amount of matrix has been deposited. 6 figs.

CVD apparatus and process for the preparation of fiber-reinforced ceramic composites

DOEpatents

Caputo, Anthony J.; Devore, Charles E.; Lowden, Richard A.; Moeller, Helen H.

1990-01-01

An apparatus and process for the chemical vapor deposition of a matrix into a preform having circumferentially wound ceramic fibers, comprises heating one surface of the preform while cooling the other surface thereof. The resulting product may have fibers that are wound on radial planes or at an angle from the radial planes. The fibers can also be precoated with pyrolytic carbon before application of the matrix. The matrix is applied by passing reactant gas through the preform thereof to the other side thereof for the initial deposition of matrix near such other surface of the preform. The matrix fills in the preform from the other side surface thereof to the surface of the side of application thereof until a desired amount of matrix has been deposited.

Assessment of laser photobiomodulation and polarized light on the healing of cutaneous wounds on euthyroid and hypothyroid induced rats

NASA Astrophysics Data System (ADS)

Ramalho, Luciana Maria Pedreira; Weyll, Barbara Mayoral Pedroso; da Costa Lino, Maíra Dória M.; Ramalho, Maria Jose Pedreira; Barbosa Pinheiro, Antonio Luis

2010-02-01

The aim of this study was to assess the influence of low-level laser therapy (LLLT) or polarized light (PL) in cutaneous wound healing of hypothyroid rats at dosages of 20 or 40J/cm2. Bioestimulatory effects of Laser radiation and Polarized light are recognized alternative therapies to improve healing on systemic disease patients, but their usefulness in the improvement of hypothyroidism healing impairment is uncertain till date. Forty Wistar rats were used in this study. Hypothyroidism was propylthiouracil- induced. Standard excisional cutaneous wounds were created without suturing and LLLT (λ660nm, 30mW, φ 3mm) or PL (λ 400-2000nm, 40mW, φ 10mm) was applied every 48 hours up to seven days on experimental groups. The rats were killed on the eighth day when wound contraction was assessed. The healing features were evaluated by light microscopy (H/E and Sirius Red). The cutaneous wounds of hypothyroid rats showed delayed healing process characterized by reduced thickness of epithelial layers, incipient formation of disorganized collagen fibers and wound contraction to a lesser extent (FISHER, p=0.0276), when compared to the euthyroid group. The use of both the Laser and Polarized Light on hypothyroid rats increased the amount of fibroblasts and the thickness of collagen fibers, especially on the L 20J/cm2 group. Euthyroid rats have still demonstrated more regular collagen fibers pattern than hypothyroid rats. It was therefore concluded that hypothyroidism delays wound healing and both Laser photobiomodulation and Polarized Light at 20j/cm2 dosages had improved the healing process in hypothyroid rats.

Highly Absorbent Antibacterial Hemostatic Dressing for Healing Severe Hemorrhagic Wounds

PubMed Central

Li, Ting-Ting; Lou, Ching-Wen; Chen, An-Pang; Lee, Mong-Chuan; Ho, Tsing-Fen; Chen, Yueh-Sheng; Lin, Jia-Horng

2016-01-01

To accelerate healing of severe hemorrhagic wounds, a novel highly absorbent hemostatic dressing composed of a Tencel®/absorbent-cotton/polylactic acid nonwoven base and chitosan/nanosilver antibacterial agent was fabricated by using a nonwoven processing technique and a freeze-drying technique. This study is the first to investigate the wicking and water-absorbing properties of a nonwoven base by measuring the vertical wicking height and water absorption ratio. Moreover, blood agglutination and hemostatic second tests were conducted to evaluate the hemostatic performance of the resultant wound dressing. The blending ratio of fibers, areal weight, punching density, and fiber orientation, all significantly influenced the vertical moisture wicking property. However, only the first two parameters markedly affected the water absorption ratio. After the nonwoven base absorbed blood, scanning electron microscope (SEM) observation showed that erythrocytes were trapped between the fibrin/clot network and nonwoven fibers when coagulation pathways were activated. Prothrombin time (PT) and activated partial thromboplastin time (APTT) blood agglutination of the resultant dressing decreased to 14.34 and 50.94 s, respectively. In the femoral artery of the rate bleeding model, hemostatic time was saved by 87.2% compared with that of cotton cloth. Therefore, the resultant antibacterial wound dressing demonstrated greater water and blood absorption, as well as hemostatic performance, than the commercially available cotton cloth, especially for healing severe hemorrhagic wounds. PMID:28773912

Electrospinning of curcumin loaded chitosan/poly (lactic acid) nanofilm and evaluation of its medicinal characteristics

NASA Astrophysics Data System (ADS)

Dhurai, Bhaarathi; Saraswathy, Nachimuthu; Maheswaran, Ramasamy; Sethupathi, Ponnusamy; Vanitha, Palanisamy; Vigneshwaran, Sukumar; Rameshbabu, Venugopal

2013-12-01

The curcumin loaded chitosan/poly (lactic acid) (PLA) nanofibers were produced using electrospinning. Box—Behnken experimental design was used for the optimization of variables (-1, 0, + 1 coded level) like chitosan/PLA strength (% w/v), curcumin strength (% w/v) and applied voltage (kV) to obtain uniform fiber diameter. The morphology of nanofibers was shown by SEM. Molecular interactions and the presence of each chemical compound of curcumin loaded chitosan/PLA fibers were characterized by FTIR and EDX analysis. Antioxidant, drug release and in vitro cytotoxicity tests were performed to evaluate the suitability of nanofibers that would be used for wound healing. In vivo wound healing studies on excision and incision wounds created on rat model showed significant reduction of wound area when compared to untreated. The better healing efficiency can be attributed to the presence of curcumin and chitosan.

Optical Fiber Design And Fabrication: Discussion On Recent Developments

NASA Astrophysics Data System (ADS)

Roy, Philippe; Devautour, Mathieu; Lavoute, Laure; Gaponov, Dmitry; Brasse, Gurvan; Hautreux, Stéphanie; Février, Sébastien; Restoin, Christine; Auguste, Jean-Louis; Gérôme, Frédéric; Humbert, Georges; Blondy, Jean-Marc

2008-10-01

Level of emitted power and beam quality of singlemode fiber lasers have been drastically increased at the expense of loss due to bend sensitivity, simplicity of manufacturing and packaging. Furthermore, the extension of the spectral coverage was primarily explored by exploiting non-linear effects, neglecting numerous possible transitions of rare earths. Through different research areas, we demonstrate the possibilities offered by new fiber designs and alternative methods of manufacturing. Photonic Band Gap fibers reconcile diffraction limited beam and large mode area with low bending loss. 80% slope efficiency is demonstrated together with a robust propagation allowing the fiber to be tightly bent until wounding radii as small as 6 cm. Highly ytterbium doped multimode core surrounded by high refractive index rods fiber exhibits a transverse singlemode behavior under continuous wave laser regime. A robust LP01 mode is observed and filtering effect is clearly observed. A non CVD process based on silica sand vitrification allows the synthesis of large and highly doped core with high index homogeneity, opening the way to design of efficient large mode area fiber lasers. 74% slope efficiency is measured, demonstrating the good quality of the core material. Finally, the use of rare earth (Er3+) doped zirconia nanocrystals in silica matrix offers a large panel of ignored energy transitions for visible or off-usual band of emission.

The mechanical fingerprint of murine excisional wounds.

PubMed

Pensalfini, Marco; Haertel, Eric; Hopf, Raoul; Wietecha, Mateusz; Werner, Sabine; Mazza, Edoardo

2018-01-01

A multiscale mechanics approach to the characterization of murine excisional wounds subjected to uniaxial tensile loading is presented. Local strain analysis at a physiological level of tension uncovers the presence of two distinct regions within the wound: i) a very compliant peripheral cushion and ii) a core area undergoing modest deformation. Microstructural visualizations of stretched wound specimens show negligible engagement of the collagen located in the center of a 7-day old wound; fibers remain coiled despite the applied tension, confirming the existence of a mechanically isolated wound core. The compliant cushion located at the wound periphery appears to protect the newly-formed tissue from excessive deformation during the phase of new tissue formation. The early remodeling phase (day 14) is characterized by a restored mechanical connection between far field and wound center. The latter remains less deformable, a characteristic possibly required for cell activities during tissue remodeling. The distribution of fibrillary collagens at these two time points corresponds well to the identified heterogeneity of mechanical properties of the wound region. This novel approach provides new insight into the mechanical properties of wounded skin and will be applicable to the analysis of compound-treated wounds or wounds in genetically modified tissue. Biophysical characterization of healing wounds is crucial to assess the recovery of the skin barrier function and the associated mechanobiological processes. For the first time, we performed highly resolved local deformation analysis to identify mechanical characteristics of the wound and its periphery. Our results reveal the presence of a compliant cushion surrounding a stiffer wound core; we refer to this heterogeneous mechanical behavior as "mechanical fingerprint" of the wound. The mechanical response is shown to progress towards that of the intact skin as healing takes place. Histology and multiphoton microscopy suggest that wounded skin recovers its mechanical function via progressive reconnection of the newly-deposited collagen fibers with the surrounding intact matrix. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Combination of ciclopirox olamine and sphingosine-1-phosphate as granulation enhancer in diabetic wounds.

PubMed

Lim, Natalie Sheng Jie; Sham, Adeline; Chee, Stella Min Ling; Chan, Casey; Raghunath, Michael

2016-09-01

Granulation tissue formation requires a robust angiogenic response. As granulation tissue develops, collagen fibers are deposited and compacted. Forces generated in the wake of this process drive wound contraction to reduce the wound area. In diabetics, both angiogenesis and wound contraction are diminished leading to impaired wound healing. To emulate this pathology and to address it pharmacologically, we developed a wound healing model in the diabetic Zucker fatty rat and tested a topical proangiogenic strategy combining antifungal agent ciclopirox olamine (CPX) and lysophospholipid sphingosine-1-phosphate (S1P) to promote diabetic wound closure. In vitro, we demonstrated that CPX + S1P up-regulates a crucial driver of angiogenesis, hypoxia-inducible factor-1, in endothelial cells. Injection of CPX + S1P into subcutaneously implanted sponges in experimental rats showed, in an additive manner, a fivefold increased endothelial infiltration and lectin-perfused vessel length. We developed a splinted diabetic rodent model to achieve low wound contraction rates that are characteristic for the healing mode of diabetic ulcers in humans. We discovered specific dorsal sites that allowed for incremental full-thickness excisional wound depths from 1 mm (superficial) to 3 mm (deep). This enabled us to bring down wound contraction from 51% in superficial wounds to 8% in deep wounds. While the effects of topical gel treatment of CPX + S1P were masked by the rodent-characteristic dominant contraction in superficial wounds, they became clearly evident in deep diabetic wounds. Here, a fivefold increase of functional large vessels resulted in accelerated granulation tissue formulation, accompanied by a 40% increase of compacted thick collagen fibers. This was associated with substantially reduced matrix metalloproteinase-3 and -13 expression. These findings translated into a fivefold increase in granulation-driven contraction, promoting diabetic wound closure. With CPX and S1P analogues already in clinical use, their combination presents itself as an attractive proangiogenic treatment to be repurposed for diabetic wound healing. © 2016 by the Wound Healing Society.

The multifunctional wound dressing with core-shell structured fibers prepared by coaxial electrospinning

NASA Astrophysics Data System (ADS)

Wei, Qilin; Xu, Feiyang; Xu, Xingjian; Geng, Xue; Ye, Lin; Zhang, Aiying; Feng, Zengguo

2016-06-01

The non-woven wound dressing with core-shell structured fibers was prepared by coaxial electrospinning. The polycaprolactone (PCL) was electrospun as the fiber's core to provide mechanical strength whereas collagen was fabricated into the shell in order to utilize its good biocompatibility. Simultaneously, the silver nanoparticles (Ag-NPs) as anti-bacterial agent were loaded in the shell whereas the vitamin A palmitate (VA) as healing-promoting drug was encapsulated in the core. Resulting from the fiber's core-shell structure, the VA released from the core and Ag-NPs present in the shell can endow the dressing both heal-promoting and anti-bacteria ability simultaneously, which can greatly enhance the dressing's clinical therapeutic effect. The dressing can maintain high swelling ratio of 190% for 3 d indicating its potential application as wet dressing. Furthermore, the dressing's anti-bacteria ability against Staphylococcus aureus was proved by in vitro anti-bacteria test. The in vitro drug release test showed the sustainable release of VA within 72 h, while the cell attachment showed L929 cells can well attach on the dressing indicating its good biocompatibility. In conclusion, the fabricated nanofibrous dressing possesses multiple functions to benefit wound healing and shows promising potential for clinical application.

Curing A Large Composite Cylinder Without An Autoclave

NASA Technical Reports Server (NTRS)

Frazer, Robert E.

1992-01-01

Proposed technique provides application of heat and pressure to cure fiber-wound composite cylinder too large to fit in autoclave. Tube wound around cylinder applies pressure. Blanket distributes pressure. Pressure expels gas bubbles from material. Heat applied by conventional methods.

Recent advances in lightweight, filament-wound composite pressure vessel technology

NASA Technical Reports Server (NTRS)

Lark, R. F.

1977-01-01

A review of recent advances is presented for lightweight, high performance composite pressure vessel technology that covers the areas of design concepts, fabrication procedures, applications, and performance of vessels subjected to single cycle burst and cyclic fatigue loading. Filament wound fiber/epoxy composite vessels were made from S glass, graphite, and Kevlar 49 fibers and were equipped with both structural and nonstructural liners. Pressure vessels structural efficiencies were attained which represented weight savings, using different liners, of 40 to 60 percent over all titanium pressure vessels. Significant findings in each area are summarized.

Effect of Bamboo Viscose on the Wicking and Moisture Management Properties of Gauze

NASA Astrophysics Data System (ADS)

Akbar, Abdul R.; Su, Siwei; Amjad, Bilal; Cai, Yingjie; Lin, Lina

2017-12-01

Bamboo viscose or regenerated cellulose fibers were used to check their absorbency properties effect on the wicking and moisture management in gauzes. Bamboo viscose and cotton fibers were spun into five different yarn samples with different fiber proportion by ring spinning. Fifteen different gauze samples were made of these yarn samples. The gauze samples were subjected to wicking test to check the wicking ability. Water vapor transmission test was applied to check the vapor transmission rate. These tests were applied to measure the effectiveness of bamboo viscose, cotton and blended gauze samples in wound healing. Pure bamboo gauzes and gauzes with high content of bamboo fiber, i.e. 75B:25C and 50B:50C, shows better wicking and vapor transmission properties. It makes gauzes with high bamboo viscose suitable for wound care applications because of moisture absorbency.

Wound healing property of milk in full thickness wound model of rabbit.

PubMed

Hemmati, Ali Asghar; Larki-Harchegani, Amir; Shabib, Somayeh; Jalali, Amir; Rezaei, Anahita; Housmand, Gholamreza

2018-04-22

Wound healing consists of several continuous phases in which various cells and chemical intermediates are involved. Milk as a rich source of nutritional elements has proved to have potential benefits for treatment of various diseases. The present study was designed to investigate the healing effect of low-fat cow's milk on an open skin wound model in the rabbit. The 2%, 5%, and 10% (w/w) ointments of lyophilized powder of low-fat milk were prepared in the eucerin base and were applied twice daily in the treatment groups. Phenytoin 1% ointment was used as a standard control. The healing effect of the milk ointment (MO) was evaluated through the measurement of wound surface area, the extent of tissue tension, and the content of hydroxyproline. Histological evaluation of skin tissue specimens was also performed using hematoxylin and eosin staining. The results showed that the healing rate in the treatment group was significantly higher than that of untreated group and eucerin group (p < 0.01). The best healing effect was seen in 5% milk ointment with the shortest healing time (15 days) and the highest tissue tension in comparison to other groups. Although the tissue hydroxyproline content in this group was slightly lower than that of the phenytoin group, this difference was not significant. Histologic, findings indicated increased collagen fibers, increased fibroblasts and an evident decrease in inflammatory cells in that group. It can, therefore, be concluded that low-fat cow's milk has significant beneficial effects on skin wound healing. Therefore, it may be used as a healing agent in different types of the wound in humans after certain clinical trials. Copyright © 2018 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

635nm diode laser biostimulation on cutaneous wounds

NASA Astrophysics Data System (ADS)

Solmaz, Hakan; Gülsoy, Murat; Ülgen, Yekta

2014-05-01

Biostimulation is still a controversial subject in wound healing studies. The effect of laser depends of not only laser parameters applied but also the physiological state of the target tissue. The aim of this project is to investigate the biostimulation effects of 635nm laser irradiation on the healing processes of cutaneous wounds by means of morphological and histological examinations. 3-4 months old male Wistar Albino rats weighing 330 to 350 gr were used throughout this study. Low-level laser therapy was applied through local irradiation of red light on open skin excision wounds of 5mm in diameter prepared via punch biopsy. Each animal had three identical wounds on their right dorsal part, at which two of them were irradiated with continuous diode laser of 635nm in wavelength, 30mW of power output and two different energy densities of 1 J/cm2 and 3 J/cm2. The third wound was kept as control group and had no irradiation. In order to find out the biostimulation consequences during each step of wound healing, which are inflammation, proliferation and remodeling, wound tissues removed at days 3, 7, 10 and 14 following the laser irradiation are morphologically examined and than prepared for histological examination. Fragments of skin including the margin and neighboring healthy tissue were embedded in paraffin and 6 to 9 um thick sections cut are stained with hematoxylin and eosin. Histological examinations show that 635nm laser irradiation accelerated the healing process of cutaneous wounds while considering the changes of tissue morphology, inflammatory reaction, proliferation of newly formed fibroblasts and formation and deposition of collagen fibers. The data obtained gives rise to examine the effects of two distinct power densities of low-level laser irradiation and compare both with the non-treatment groups at different stages of healing process.

Induction of low-level hydrogen peroxide generation by unbleached cotton nonwovens as potential or wound healing applications

USDA-ARS?s Scientific Manuscript database

Greige cotton is an intact plant fiber. The cuticle and primary cell wall near the outer surface of the cotton fiber contains pectin, peroxidases, superoxide dismutase (SOD), and trace metals, which are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. The compon...

A comparison of hemorrhage control and hydrogen peroxide generation in commercial and cotton-based wound dressing materials

USDA-ARS?s Scientific Manuscript database

Nonwoven UltraCleanTM Cotton (highly cleaned and hydroentangled, greige cotton) retains the native wax and pectin content (~2%) of the cotton fiber traditionally removed from scoured and bleached cotton gauze, yet potentially affording wound healing properties. In vitro thromboelastography, hydrog...

Exact solution of conductive heat transfer in cylindrical composite laminate

NASA Astrophysics Data System (ADS)

Kayhani, M. H.; Shariati, M.; Nourozi, M.; Karimi Demneh, M.

2009-11-01

This paper presents an exact solution for steady-state conduction heat transfer in cylindrical composite laminates. This laminate is cylindrical shape and in each lamina, fibers have been wound around the cylinder. In this article heat transfer in composite laminates is being investigated, by using separation of variables method and an analytical relation for temperature distribution in these laminates has been obtained under specific boundary conditions. Also Fourier coefficients in each layer obtain by solving set of equations that related to thermal boundary layer conditions at inside and outside of the cylinder also thermal continuity and heat flux continuity between each layer is considered. In this research LU factorization method has been used to solve the set of equations.

Wound healing efficacy of a 660-nm diode laser in a rat incisional wound model.

PubMed

Suzuki, Ryoichi; Takakuda, Kazuo

2016-11-01

This study aimed to elucidate the optimum usage parameters of low reactive-level laser therapy (LLLT) in a rat incisional wound model. In Sprague-Dawley rats, surgical wounds of 15-mm length were made in the dorsal thoracic region. They were divided into groups to receive 660-nm diode laser irradiation 24 h after surgery at an energy density of 0 (control), 1, 5, or 10 J/cm 2 . Tissue sections collected on postoperative day 3 were stained with hematoxylin-eosin and an antibody for ED1 to determine the number of macrophages around the wound. Samples collected on day 7 were stained with hematoxylin-eosin and observed via polarized light microscopy to measure the area occupied by collagen fibers around the wound; day 7 skin specimens were also subjected to mechanical testing to evaluate tensile strength. On postoperative day 3, the numbers of macrophages around the wound were significantly lower in the groups receiving 1 and 5 J/cm 2 irradiation, compared to the control and 10 J/cm 2 irradiation groups (p < 0.01). The area occupied by collagen fibers in day 7 was largest in 5 J/cm 2 group, followed by 1 J/cm 2 group, although this difference was not significant. The day 7 tensile test demonstrated significantly greater rupture strength in healing tissues from 1 and 5 J/cm 2 irradiation groups, compared to the control group (p < 0.05). Thus, LLLT with a 660-nm diode laser with energy density of 1 and 5 J/cm 2 enhanced wound healing in a rat incisional wound model. However, a higher radiation energy density yielded no significant enhancement.

Advanced stitching technology

NASA Technical Reports Server (NTRS)

Scardino, Frank L.

1992-01-01

In the design of textile composites, the selection of materials and constructional techniques must be matched with product performance, productivity, and cost requirements. Constructional techniques vary. A classification of various textile composite systems is given. In general, the chopped fiber system is not suitable for structural composite applications because of fiber discontinuity, uncontrolled fiber orientation and a lack of fiber integration or entanglement. Linear filament yarn systems are acceptable for structural components which are exposed to simple tension in their applications. To qualify for more general use as structural components, filament yarn systems must be multi-directionally positioned. With the most sophisticated filament winding and laying techniques, however, the Type 2 systems have limited potential for general load-bearing applications because of a lack of filament integration or entanglement, which means vulnerability to splitting and delamination among filament layers. The laminar systems (Type 3) represented by a variety of simple fabrics (woven, knitted, braided and nonwoven) are especially suitable for load-bearing panels in flat form and for beams in a roled up to wound form. The totally integrated, advanced fabric system (Type 4) are thought to be the most reliable for general load-bearing applications because of fiber continuity and because of controlled multiaxial fiber orientation and entanglement. Consequently, the risk of splitting and delamination is minimized and practically omitted. Type 4 systems can be woven, knitted, braided or stitched through with very special equipment. Multiaxial fabric technologies are discussed.

Effect of fiber and dye degradation products (FDP) on burn wound healing.

PubMed

Knox, F S; Wachtel, T L; McCahan, G R; Knapp, S C

1979-10-01

Upon exposure to the thermal environment of an aircraft fire, many fire retardant fabrics off-gas fiber and dye degradation products (FDP). Condensation of these products on human skin raises questions concerning possible deleterious effects on burn wound healing. A porcine bioassay was used to study the physiological effects of FDP. Selected areas of living skin, protected by dyed aromatic polyamides and polybenzimidazole fabrics, were exposed to a thermal source adjusted to simulate a postcrash JP-4 fuel fire. Burn sites contaminated with FDP were evaluated by clinical observation ane to begin epithelialization, time to closure of an open wound, and the amount and type of cicatrix formation. The experiment showed that each fabric has unique off-gasing products. The greatest amount of FDP was deposited on the skin when the skin was covered by a single layer of shell fabric separated by a 6.35-mm air gap. The presence of an intervening cotton T-shirt decreased the amount of FDP deposited on the skin. We found no evidence that FDP caused alterations in wound healing.

Development of a bioactive glass-polymer composite for wound healing applications.

PubMed

Moura, D; Souza, M T; Liverani, L; Rella, G; Luz, G M; Mano, J F; Boccaccini, A R

2017-07-01

This study reports the production and characterization of a composite material for wound healing applications. A bioactive glass obtained by sol-gel process and doped with two different metal ions was investigated. Silver (Ag) and cobalt (Co) were chosen due to their antibacterial and angiogenic properties, respectively, very beneficial in the wound healing process. Poly(ε-caprolactone) (PCL) fibers were produced by electrospinning (ES) from a polymeric solution using acetone as a solvent. After optimization of the ES parameters, two main suspensions were prepared, namely: PCL containing bioactive glass nanoparticles (BG-NP) and PCL with Ag 2 O and CoO doped BG-NP (DP BG-NP), which were processed with different concentrations of BG-NP (0.25%, 0.5% and 0.75wt%). The composite membranes were characterized in terms of morphology, fiber diameter, weight loss, mineralization potential and mechanical performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Recent advances in lightweight, filament-wound composite pressure vessel technology

NASA Technical Reports Server (NTRS)

Lark, R. F.

1977-01-01

A review of recent advances is presented for lightweight, high-performance composite pressure vessel technology that covers the areas of design concepts, fabrication procedures, applications, and performance of vessels subjected to single-cycle burst and cyclic fatigue loading. Filament-wound fiber/epoxy composite vessels were made from S-glass, graphite, and Kevlar 49 fibers and were equipped with both structural and nonstructural liners. Pressure vessel structural efficiencies were attained which represented weight savings, using different liners, of 40 to 60 percent over all-titanium pressure vessels. Significant findings in each area are summarized including data from current NASA-Lewis Research Center contractual and in-house programs.

Graphite filament wound pressure vessels

NASA Technical Reports Server (NTRS)

Feldman, A.; Damico, J. J.

1972-01-01

Filament wound NOL rings, 4-inch and 8-inch diameter closed-end vessels involving three epoxy resin systems and three graphite fibers were tested to develop property data and fabrication technology for filament wound graphite/epoxy pressure vessels. Vessels were subjected to single-cycle burst tests at room temperature. Manufacturing parameters were established for tooling, winding, and curing that resulted in the development of a pressure/vessel performance factor (pressure x volume/weight) or more than 900,000 in. for an oblate spheroid specimen.

In-situ synthesis of AgNPs in the natural/synthetic hybrid nanofibrous scaffolds: Fabrication, characterization and antimicrobial activities.

PubMed

Maharjan, Bikendra; Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Park, Chan Hee; Kim, Cheol Sang

2017-01-01

Silver nanoparticles embedded within a nanofibrous polymer matrix have significant attention in recent years as an antimicrobial wound dressing materials. Herein, we have fabricated a novel Ag-polyurethane-zein hybrid nanofibrous scaffold for wound dressing applications. AgNPs were synthesized in-situ via reduction of silver nitrate in electrospinning solution. Varying mass composition of the components showed the pronounced effect on the morphology and physicochemical properties of the composite fibers. Field-Emission Scanning Electron Microscopy (FESEM) images revealed that PU and zein with mass ratio 2:1 produced the bead-free continuous and uniformly distributed nanofibers. Fourier-transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Thermogravimetric Analysis (TGA) confirmed the well interaction between component polymers. Compared to the pristine PU nanofibers, composite fibers showed enhanced tensile strength, young׳s modulus and surface wettability. The antibacterial capacity of the nanofibrous membrane was evaluated against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial strains via a zone of inhibition test, and the results showed high antibacterial performance for Ag incorporated composite mat. Experimental results of cell viability assay and microscopic imaging revealed that as-fabricated scaffolds have an excellent ability for fibroblast cell adhesion, proliferation and growth. Overall, as-fabricated antibacterial natural/synthetic composite scaffold can be a promising substrate for repairing skin defects. Copyright © 2016. Published by Elsevier Ltd.

Membrane damage-induced vesicle–vesicle fusion of dysferlin-containing vesicles in muscle cells requires microtubules and kinesin

PubMed Central

McDade, Joel R.; Michele, Daniel E.

2014-01-01

Mutations in the dysferlin gene resulting in dysferlin-deficiency lead to limb-girdle muscular dystrophy 2B and Myoshi myopathy in humans. Dysferlin has been proposed as a critical regulator of vesicle-mediated membrane resealing in muscle fibers, and localizes to muscle fiber wounds following sarcolemma damage. Studies in fibroblasts and urchin eggs suggest that trafficking and fusion of intracellular vesicles with the plasma membrane during resealing requires the intracellular cytoskeleton. However, the contribution of dysferlin-containing vesicles to resealing in muscle and the role of the cytoskeleton in regulating dysferlin-containing vesicle biology is unclear. Here, we use live-cell imaging to examine the behavior of dysferlin-containing vesicles following cellular wounding in muscle cells and examine the role of microtubules and kinesin in dysferlin-containing vesicle behavior following wounding. Our data indicate that dysferlin-containing vesicles move along microtubules via the kinesin motor KIF5B in muscle cells. Membrane wounding induces dysferlin-containing vesicle–vesicle fusion and the formation of extremely large cytoplasmic vesicles, and this response depends on both microtubules and functional KIF5B. In non-muscle cell types, lysosomes are critical mediators of membrane resealing, and our data indicate that dysferlin-containing vesicles are capable of fusing with lysosomes following wounding which may contribute to formation of large wound sealing vesicles in muscle cells. Overall, our data provide mechanistic evidence that microtubule-based transport of dysferlin-containing vesicles may be critical for resealing, and highlight a critical role for dysferlin-containing vesicle–vesicle and vesicle–organelle fusion in response to wounding in muscle cells. PMID:24203699

Electrokinetic and hemostatic profiles of nonwoven cellulosic/ synthetic fiber blends with unbleached cotton

USDA-ARS?s Scientific Manuscript database

Greige cotton contains waxes and pectin on the outer surface of the fiber that are removed from bleached cotton, but present added potential for wound dressing functionality. Innovations to mechanically clean and sterilize greige cotton (or non-bleached cotton) do not remove these exterior componen...

Curcumin and its topical formulations for wound healing applications.

PubMed

Mohanty, Chandana; Sahoo, Sanjeeb K

2017-10-01

Oxidative damage and inflammation have been identified, through clinical and preclinical studies, as the main causes of nonhealing chronic wounds. Reduction of persistent chronic inflammation by application of antioxidant and anti-inflammatory agents such as curcumin has been well studied. However, low aqueous solubility, poor tissue absorption, rapid metabolism and short plasma half-life have made curcumin unsuitable for systemic administration for better wound healing. Recently, various topical formulations of curcumin such as films, fibers, emulsion, hydrogels and different nanoformulations have been developed for targeted delivery of curcumin at wounded sites. In this review, we summarize and discuss different topical formulations of curcumin with emphasis on their wound-healing properties in animal models. Copyright © 2017 Elsevier Ltd. All rights reserved.

Starch/PCL composite nanofibers by co-axial electrospinning technique for biomedical applications.

PubMed

Komur, B; Bayrak, F; Ekren, N; Eroglu, M S; Oktar, F N; Sinirlioglu, Z A; Yucel, S; Guler, O; Gunduz, O

2017-03-29

In this study, starch and polycaprolactone (PCL), composite nanofibers were fabricated by co-axial needle electrospinning technique. Processing parameters such as polymer concentration, flow rate and voltage had a marked influence on the composite fiber diameter. Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), mechanical and physical properties (such as density, viscosity and electrical conductivity) of the composite fibres were evaluated. Moreover, a cell culture test was performed in order to determine their cytotoxicity for wound dressing application. The effect of starch ratio in the solution on the properties and morphological structure of the fibers produced was presented. With lower starch concentration values, the fibers have greater ultimate tensile strength characteristic (mostly 4 and 5 wt%). According to SEM results, it can be figured out that the nanofibers fabricated have good spinnability and morphology. The mean diameter of the fibers is about 150 nm. According to results of cell culture study, the finding can be determined that the increase of starch in the fiber also increases the cell viability. Composite nanofibers of starch/PCL have been prepared using a co-axial needle electrospinning technique. PCL was successfully encapsulated within starch. Fiber formation was observed for different ratio of starch. With several test, analysis and measurement performed, some important parameters such as quality and effectuality of each fiber obtained for wound dressing applications were discussed in detail.

Effects of topical oxygen therapy on ischemic wound healing.

PubMed

Rao, Congqiang; Xiao, Liling; Liu, Hongwei; Li, Shenghong; Lu, Jinqiang; Li, Jiangxuan; Gu, Shixing

2016-01-01

[Purpose] This study evaluated the effects of topical oxygen therapy on the hind limb wounds of rats under ischemic conditions. [Subjects and Methods] Twelve injured rats were treated with topical oxygen on skin wounds located on the hind limb and compared with twelve injured control rats. Indexes including gross morphology of the wound, wound healing time, wound healing rate, and histological and immunohistochemical staining of sections of wound tissue were examined at different time points after intervention. [Results] The wound healing time was shorter in the topical oxygen therapy group than the control group. The wound healing rate and granulation tissue formation in the topical oxygen therapy group showed significant improvement on days 3, 7, and 14. Through van Gieson staining, the accumulation of collagen fiber in the topical oxygen therapy group was found to have improved when compared with the control group on day 7. Through semiquantitative immunohistochemical staining, many more new vessels were found in the topical oxygen therapy group compared with the model control group on day 7. [Conclusion] The results of the experiment showed that topical oxygen therapy improved ischemic wound healing.

EASApprox® skin-stretching system: A secure and effective method to achieve wound closure.

PubMed

Song, Mingzhi; Zhang, Zhen; Liu, Tao; Liu, Song; Li, Gang; Liu, Zhaochang; Huang, Jingyang; Chen, Song; Li, Linan; Guo, Li; Qiu, Yang; Wan, Jiajia; Liu, Yuejian; Wu, Tao; Wang, Xiaoyong; Lu, Ming; Wang, Shouyu

2017-07-01

Large skin defects are commonly observed in the clinic and have attracted much attention recently. Therefore, finding an effective solution for large skin defects is a global problem. The objective of the present study was to assess the effectiveness of the EASApprox ® skin-stretching system for closing large skin defects. Skin defects (5×5 cm) were created on the forearms of 9 Bama miniature pigs, which were randomly divided into the following three groups: Direct suture, the new EASApprox ® skin-stretching device and Kirschner wires. Microcirculation was assessed before surgery and after wound closure. Following the different treatments, the defects were sutured, and wound healing was assessed based on a clinical score. Furthermore, microscopic and ultramicroscopic structures were evaluated, including collagen, elastic fibers and the microvessel density. Significant differences in the clinical score and microvessel density were observed among the groups. Additionally, the mean length obtained for elastic fibers was larger than that obtained for the other two groups. Finally, the new EASApprox ® skin-stretching device resulted in successful wound management and with only minor side effects on skin histology and microcirculation. Therefore, this method has the potential to be used for healing large skin defects.

Carbon nanotube fiber terahertz polarizer

NASA Astrophysics Data System (ADS)

Zubair, Ahmed; Tsentalovich, Dmitri E.; Young, Colin C.; Heimbeck, Martin S.; Everitt, Henry O.; Pasquali, Matteo; Kono, Junichiro

2016-04-01

Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ˜-30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2-1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

Interactions between Chloramphenicol, Carrier Polymers, and Bacteria-Implications for Designing Electrospun Drug Delivery Systems Countering Wound Infection.

PubMed

Preem, Liis; Mahmoudzadeh, Mohammad; Putrinš, Marta; Meos, Andres; Laidmäe, Ivo; Romann, Tavo; Aruväli, Jaan; Härmas, Riinu; Koivuniemi, Artturi; Bunker, Alex; Tenson, Tanel; Kogermann, Karin

2017-12-04

Antibacterial drug-loaded electrospun nano- and microfibrous dressings are of major interest as novel topical drug delivery systems in wound care. In this study, chloramphenicol (CAM)-loaded polycaprolactone (PCL) and PCL/poly(ethylene oxide) (PEO) fiber mats were electrospun and characterized in terms of morphology, drug distribution, physicochemical properties, drug release, swelling, cytotoxicity, and antibacterial activity. Computational modeling together with physicochemical analysis helped to elucidate possible interactions between the drug and carrier polymers. Strong interactions between PCL and CAM together with hydrophobicity of the system resulted in much slower drug release compared to the hydrophilic ternary system of PCL/PEO/CAM. Cytotoxicity studies confirmed safety of the fiber mats to murine NIH 3T3 cells. Disc diffusion assay demonstrated that both fast and slow release fiber mats reached effective concentrations and had similar antibacterial activity. A biofilm formation assay revealed that both blank matrices are good substrates for the bacterial attachment and formation of biofilm. Importantly, prolonged release of CAM from drug-loaded fibers helps to avoid biofilm formation onto the dressing and hence avoids the treatment failure.

Continuous topical oxygen for the treatment of chronic wounds: a pilot study.

PubMed

Woo, Kevin Y; Coutts, Patricia M; Sibbald, R Gary

2012-12-01

Oxygen is essential for all stages of wound healing. Previous research has shown topical administration of oxygen to have positive effects on wound healing. In this study, the application of transdermal continuous topical oxygen therapy (TCOT) was evaluated for its effect on chronic wound healing in 9 patients. After 4 weeks of treatment, mean wound surface area and wound infection checklist scores were significantly reduced. Signs of bacterial damage were also reduced. Findings from this study suggest TCOT may be beneficial in promoting chronic wound healing.

Ephrin-Bs Drive Junctional Downregulation and Actin Stress Fiber Disassembly to Enable Wound Re-epithelialization

PubMed Central

Nunan, Robert; Campbell, Jessica; Mori, Ryoichi; Pitulescu, Mara E.; Jiang, Wen G.; Harding, Keith G.; Adams, Ralf H.; Nobes, Catherine D.; Martin, Paul

2015-01-01

Summary For a skin wound to successfully heal, the cut epidermal-edge cells have to migrate forward at the interface between scab and healthy granulation tissue. Much is known about how lead-edge cells migrate, but very little is known about the mechanisms that enable active participation by cells further back. Here we show that ephrin-B1 and its receptor EphB2 are both upregulated in vivo, just for the duration of repair, in the first 70 or so rows of epidermal cells, and this signal leads to downregulation of the molecular components of adherens and tight (but not desmosomal) junctions, leading to loosening between neighbors and enabling shuffle room among epidermal cells. Additionally, this signaling leads to the shutdown of actomyosin stress fibers in these same epidermal cells, which may act to release tension within the wound monolayer. If this signaling axis is perturbed, then disrupted healing is a consequence in mouse and man. PMID:26549443

Substrate modulus of 3D-printed scaffolds regulates the regenerative response in subcutaneous implants through the macrophage phenotype and Wnt signaling.

PubMed

Guo, R; Merkel, A R; Sterling, J A; Davidson, J M; Guelcher, S A

2015-12-01

The growing need for therapies to treat large cutaneous defects has driven recent interest in the design of scaffolds that stimulate regenerative wound healing. While many studies have investigated local delivery of biologics as a restorative approach, an increasing body of evidence highlights the contribution of the mechanical properties of implanted scaffolds to wound healing. In the present study, we designed poly(ester urethane) scaffolds using a templated-Fused Deposition Modeling (t-FDM) process to test the hypothesis that scaffolds with substrate modulus comparable to that of collagen fibers enhance a regenerative versus a fibrotic response. We fabricated t-FDM scaffolds with substrate moduli varying from 5 to 266 MPa to investigate the effects of substrate modulus on healing in a rat subcutaneous implant model. Angiogenesis, cellular infiltration, collagen deposition, and directional variance of collagen fibers were maximized for wounds treated with scaffolds having a substrate modulus (Ks = 24 MPa) comparable to that of collagen fibers. The enhanced regenerative response in these scaffolds was correlated with down-regulation of Wnt/β-catenin signaling in fibroblasts, as well as increased polarization of macrophages toward the restorative M2 phenotype. These observations highlight the substrate modulus of the scaffold as a key parameter regulating the regenerative versus scarring phenotype in wound healing. Our findings further point to the potential use of scaffolds with substrate moduli tuned to that of the native matrix as a therapeutic approach to improve cutaneous healing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigation on Curcumin nanocomposite for wound dressing.

PubMed

Venkatasubbu, G Devanand; Anusuya, T

2017-05-01

Curcuma longa (turmeric) has a long history of use in medicine as a treatment for inflammatory conditions. The primary active constituent of turmeric and the one responsible for its vibrant yellow color is curcumin. Curcumin is used for treatment of wound and inflammation. It had antimicrobial and antioxidant property. It has low intrinsic toxicity and magnificent properties like with comparatively lesser side-effects. Cotton cloth is one of the most successful wound dressings which utilize the intrinsic properties of cotton fibers. Modern wound dressings, however, require other properties such as antibacterial and moisture maintaining capabilities. In this study, conventional cotton cloth was coated with Curcumin composite for achieving modern wound dressing properties. Curcumin nanocomposite is characterized. The results show that coated cotton cloth with Curcumin nanocomposite has increased drying time (74%) and water absorbency (50%). Furthermore, they show antibacterial efficiency against bacterial species present in wounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Sealing Penetrating Eye Injuries Using Photoactivated Bonding

DTIC Science & Technology

2014-10-01

treatment parameters that produce strong, immediate water- tight sealing of penetrating cornea and scleral wounds using rabbit eye models. The seal...conventional, bare fiber system using ex vivo rabbit eyes and the standard treatment protocol (Appendix 1). The bonding strength produced by two...wounds in rabbit eyes . Initial studies demonstrated that thermal damage to the iris are not a concern during the 7 treatment . A prototype light delivery

Application of VitaVallis dressing for infected wounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirilova, N. V., E-mail: n.kirilova@vitavallis.com; Fomenko, A. N., E-mail: alserova@ispms.tsc.ru; Korovin, M. S., E-mail: msk@ispms.tsc.ru

Today there is a growing demand for safe and efficient antimicrobial dressings for infected wound treatment. The antimicrobial sorption material for VitaVallis dressings was produced by one-stage oxidation of aluminum nanopowder in water in the presence of fibrous acetylcellulose matrix. Scanning electron microscopy revealed that the material is made up of fibers of diameter 1.5–3.0 µm with adhered agglomerated alumina nanosheets. An antimicrobial study revealed a high inhibitory effect of VitaVallis against the growth of gram-negative (E.coli, P. aeruginosa) and gram-positive (S. aureus) strains. The antimicrobial activity of the dressing against microbial pathogens on the wound surface was demonstrated in inmore » vivo experiments on male rats. The dressing was also tested on volunteer patients. The testing showed reduction of the wound healing period, accelerated cleaning of the infected wound and enhanced tissue regeneration in the wound. The results demonstrate that the VitaVallis dressing can be used for the treatment of deep infected wounds.« less

Role of non-mulberry silk fibroin in deposition and regulation of extracellular matrix towards accelerated wound healing.

PubMed

Chouhan, Dimple; Chakraborty, Bijayshree; Nandi, Samit K; Mandal, Biman B

2017-01-15

Bombyx mori silk fibroin (BMSF) as biopolymer has been extensively explored in wound healing applications. However, limited study is available on the potential of silk fibroin (SF) from non-mulberry (Antheraea assama and Philosamia ricini) silk variety. Herein, we have developed non-mulberry SF (NMSF) based electrospun mats functionalized with epidermal growth factor (EGF) and ciprofloxacin HCl as potential wound dressing. The NMSF based mats exhibited essential properties of wound dressing like biocompatibility, high water retention capacity (440%), water vapor transmission rate (∼2330gm -2 day -1 ), high elasticity (∼2.6MPa), sustained drug release and antibacterial activity. Functionalized NMSF mats enhanced the proliferation of human dermal fibroblasts and HaCaT cells in vitro as compared to non-functionalized mats (p⩽0.01) showing effective delivery of EGF. Extensive in vivo wound healing assesment demonstrated accelerated wound healing, enhanced re-epithelialization, highly vascularized granulation tissue and higher wound maturity as compared to BMSF based mats. NMSF mats treated wounds showed regulated deposition of mature elastin, collagen and reticulin fibers in the extracellular matrix of skin. Presence of skin appendages and isotropic collagen fibers in the regenerated skin also demonstrated scar-less healing and aesthetic wound repair. A facile fabrication of a ready-to-use bioactive wound dressing capable of concomitantly accelerating the healing process as well as deposition of the extracellular matrix (ECM) to circumvent further scarring complicacies has become a focal point of research. In this backdrop, our present work is based on non-mulberry silk fibroin (NMSF) electrospun antibiotic loaded semi-occlusive mats, mimicking the ECM of skin in terms of morphology, topology, microporous structure and mechanical stiffness. Regulation of ECM deposition and isotropic orientation evinced the potential of the mat as an instructive platform for skin regeneration. The unique peptide motifs of NMSF assisted the augmented recruitment of fibroblast, keratinocytes and endothelial cells leading to accelerated wound healing. Early progression of mature granulation, faster re-epithelialization and angiogenesis in the wounds in in vivo rabbit model forwarded the blended nanofibrous mats of NMSF and PVA ferrying EGF, apt for scarless healing. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The design, characteristics, and application of polyurethane dressings using the electrospinning process

NASA Astrophysics Data System (ADS)

Kampeerapappun, Piyaporn

In general, a dressing is used to protect and help heal wounds. There are several types of dressings on the market such as hydrocolloid, hydrogel, and medicated dressings. One technique for making a dressing is electrospinning, which is a very simple procedure used to produce fibers. Due to much smaller fiber-diameters than produced with the conventional technique, the fibers from electrospinning have unique properties: high porosity and high surface areas, which are advantageous for wound healing. In this research, the fibers were electrospun using polyurethane, TecophilicRTM or TecoflexRTM, with various additives. First, multilayer transdermal electrospun dressings, four and five-layers, were developed that allowed for the controlled release of nitric oxide (NO) from a NO2 -/ascorbic acid system encapsulated in polymer nanofibers. The amount of NO released from each wound dressing was investigated. Both the four and five-layer dressings were tested for morphology of fibers, water absorption, nitrite distribution, NO release profile after sterilization by gamma radiation, and stability. In the case of the four-layer transdermal dressing, the dressing was tested in diabetic, periodontal, and cutaneous leishmaniasis patients. Furthermore, the color change of dressing was investigated. TecophilicRTM was also spun with an antimicrobial agent, which was added to the TecophilicRTM solution to electrospin an antimicrobial dressing. The morphology of fibers was tested using an optical microscope and the water absorption, uniformity, and percent extraction of dressing were also determined. In addition, the efficiency of the antimicrobial agent in the dressing was determined according to SN 195920-1994 and ASTM 2149-01. Another NO-releasing dressing was developed employing the NO donor molecules, sodium salt of linear polyethylenimine NONOates (LPEINO-Na) and calcium salt of linear polyethylenimine NONOates (LPEINO-Ca), which were electrospun with TecophilicRTM. The NO release profiles for the LPEINO fibers were generated using a nitric oxide analyzer (NOA) and distribution of the particles in the dressing was examined. Moreover, the amount of NO released after patch storage for 1 and 2 months was determined.

Use of topical haemoglobin on sloughy wounds in the community setting.

PubMed

Bateman, Sharon Dawn

2015-09-01

This evaluation aimed to determine whether the use of a haemoglobin spray solution expedited sloughy wound healing. A descriptive evaluation was undertaken within a community setting exploring 25 patients presenting with sloughy healing and non-healing wounds, and the effects of 8 topically administered haemoglobin treatments over a 4-week period. Standard wound cleansing and dressing management were continued, with no changes to pre-evaluation regimens, and care being provided by the patients themselves or by a carer. Data were collected weekly with regard to primary outcomes of slough reduction, wound surface area reduction, patient ease of use (self-care), and overall product experience. At 4 weeks, all wounds demonstrated positive measured endpoints of slough elimination and continued wound-size reduction. Patients and carers found the product easy to use (self-caring) with an overall positive wound care experience. The administration of a haemoglobin spray solution on patients presenting with sloughy wounds resulted in positive healing outcomes of slough elimination and wound reduction alongside positive self-care and product satisfaction. Continued evaluation is recommended to build upon the evidence of this form of treatment.

Injectable Polyurethane Composite Scaffolds Delay Wound Contraction and Support Cellular Infiltration and Remodeling in Rat Excisional Wounds

PubMed Central

Adolph, Elizabeth J.; Hafeman, Andrea E.; Davidson, Jeffrey M.; Nanney, Lillian B.; Guelcher, Scott A.

2011-01-01

Injectable scaffolds present compelling opportunities for wound repair and regeneration due to their ability to fill irregularly shaped defects and deliver biologics such as growth factors. In this study, we investigated the properties of injectable polyurethane biocomposite scaffolds and their application in cutaneous wound repair using a rat excisional model. The scaffolds have a minimal reaction exotherm and clinically relevant working and setting times. Moreover, the biocomposites have mechanical and thermal properties consistent with rubbery elastomers. In the rat excisional wound model, injection of settable biocomposite scaffolds stented the wounds at early time points, resulting in a regenerative rather than a scarring phenotype at later time points. Measurements of wound width and thickness revealed that the treated wounds were less contracted at day 7 compared to blank wounds. Analysis of cell proliferation and apoptosis showed that the scaffolds were biocompatible and supported tissue ingrowth. Myofibroblast formation and collagen fiber organization provided evidence that the scaffolds have a positive effect on extracellular matrix remodeling by disrupting the formation of an aligned matrix under elevated tension. In summary, we have developed an injectable biodegradable polyurethane biocomposite scaffold that enhances cutaneous wound healing in a rat model. PMID:22105887

Removal of the basement membrane enhances corneal wound healing.

PubMed

Pal-Ghosh, Sonali; Pajoohesh-Ganji, Ahdeah; Tadvalkar, Gauri; Stepp, Mary Ann

2011-12-01

Recurrent corneal erosions are painful and put patients' vision at risk. Treatment typically begins with debridement of the area around the erosion site followed by more aggressive treatments. An in vivo mouse model has been developed that reproducibly induces recurrent epithelial erosions in wild-type mice spontaneously within two weeks after a single 1.5 mm corneal debridement wound created using a dulled-blade. This study was conducted to determine whether 1) inhibiting MMP9 function during healing after dulled-blade wounding impacts erosion development and 2) wounds made with a rotating-burr heal without erosions. Oral or topical inhibition of MMPs after dulled-blade wounding does not improve healing. Wounds made by rotating-burr heal with significantly fewer erosions than dulled-blade wounds. The localization of MMP9, β4 integrin and basement membrane proteins (LN332 and type VII collagen), immune cell influx, and reinnervation of the corneal nerves were compared after both wound types. Rotating-burr wounds remove the anterior basement membrane centrally but not at the periphery near the wound margin, induce more apoptosis of corneal stromal cells, and damage more stromal nerve fibers. Despite the fact that rotating-burr wounds do more damage to the cornea, fewer immune cells are recruited and significantly more wounds resolve completely. Copyright © 2011 Elsevier Ltd. All rights reserved.

Aligned fibers direct collective cell migration to engineer closing and nonclosing wound gaps

PubMed Central

Sharma, Puja; Ng, Colin; Jana, Aniket; Padhi, Abinash; Szymanski, Paige; Lee, Jerry S. H.; Behkam, Bahareh; Nain, Amrinder S.

2017-01-01

Cell emergence onto damaged or organized fibrous extracellular matrix (ECM) is a crucial precursor to collective cell migration in wound closure and cancer metastasis, respectively. However, there is a fundamental gap in our quantitative understanding of the role of local ECM size and arrangement in cell emergence–based migration and local gap closure. Here, using ECM-mimicking nanofibers bridging cell monolayers, we describe a method to recapitulate and quantitatively describe these in vivo behaviors over multispatial (single cell to cell sheets) and temporal (minutes to weeks) scales. On fiber arrays with large interfiber spacing, cells emerge (invade) either singularly by breaking cell–cell junctions analogous to release of a stretched rubber band (recoil), or in groups of few cells (chains), whereas on closely spaced fibers, multiple chains emerge collectively. Advancing cells on fibers form cell streams, which support suspended cell sheets (SCS) of various sizes and curvatures. SCS converge to form local gaps that close based on both the gap size and shape. We document that cell stream spacing of 375 µm and larger hinders SCS advancement, thus providing abilities to engineer closing and nonclosing gaps. Altogether we highlight the importance of studying cell-fiber interactions and matrix structural remodeling in fundamental and translational cell biology. PMID:28747440

Polymer fiber-based models of connective tissue repair and healing.

PubMed

Lee, Nancy M; Erisken, Cevat; Iskratsch, Thomas; Sheetz, Michael; Levine, William N; Lu, Helen H

2017-01-01

Physiologically relevant models of wound healing are essential for understanding the biology of connective tissue repair and healing. They can also be used to identify key cellular processes and matrix characteristics critical for the design of soft tissue grafts. Modeling the various stages of repair post tendon injury, polymer meshes of varying fiber diameter (nano-1 (390 nm) < nano-2 (740 nm) < micro (1420 nm)) were produced. Alignment was also introduced in the nano-2 group to model matrix undergoing biological healing rather than scar formation. The response of human tendon fibroblasts on these model substrates were evaluated over time as a function of fiber diameter and alignment. It was observed that the repair models of unaligned nanoscale fibers enhanced cell growth and collagen synthesis, while these outcomes were significantly reduced in the mature repair model consisting of unaligned micron-sized fibers. Organization of paxillin and actin on unaligned meshes was enhanced on micro- compared to nano-sized fibers, while the expression and activity of RhoA and Rac1 were greater on nanofibers. In contrast, aligned nanofibers promoted early cell organization, while reducing excessive cell growth and collagen production in the long term. These results show that the early-stage repair model of unaligned nanoscale fibers elicits a response characteristic of the proliferative phase of wound repair, while the more mature model consisting of unaligned micron-sized fibers is more representative of the remodeling phase by supporting cell organization while suppressing growth and biosynthesis. Interestingly, introduction of fiber alignment in the nanofiber model alters fibroblast response from repair to healing, implicating matrix alignment as a critical design factor for circumventing scar formation and promoting biological healing of soft tissue injuries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced Cutaneous Wound Healing In Vivo by Standardized Crude Extract of Poincianella pluviosa

PubMed Central

Moreira, Eduarda Antunes; de Morais, Gutierrez Rodrigues; Pacheco, Isabela Almeida

2016-01-01

Wound healing is a complex process that involves several biological events, and a delay in this process may cause economic and social problems for the patient. The search continues for new alternative treatments to aid healing, including the use of herbal medicines. Members of the genus Caesalpinia are used in traditional medicine to treat wounds. The related species Poincianella pluviosa (DC.) L.P. Queiroz increases the cell viability of keratinocytes and fibroblasts and stimulates the proliferation of keratinocytes in vitro. The crude extract (CE) from bark of P. pluviosa was evaluated in the wound-healing process in vivo, to validate the traditional use and the in vitro activity. Standardized CE was incorporated into a gel and applied on cutaneous wounds (TCEG) and compared with the formulation without CE (Control) for 4, 7, 10, or 14 days of treatment. The effects of the CE on wound re-epithelialization; cell proliferation; permeation, using photoacoustic spectroscopy (PAS); and proteins, including vascular endothelial growth factor (VEGF), superoxide dismutase 2 (SOD-2) and cyclooxygenase 2 (COX-2) were evaluated. The TCEG stimulated the migration of keratinocytes at day 4 and proliferation on the following days, with a high concentration of cells in metaphase at 7 days. Type I collagen formed more rapidly in the TCEG. PAS showed that the CE had permeated through the skin. TCEG stimulated VEGF at day 4 and SOD-2 and COX-2 at day 7. The results suggest that the CE promoted the regulation of proteins and helped to accelerate the processes involved in healing, promoting early angiogenesis. This led to an increase in the re-epithelialized surface, with significant mitotic activity. Maturation of collagen fibers was also enhanced, which may affect the resistance of the extracellular matrix. PAS indicated a correlation between the rate of diffusion and biological events during the healing process. The CE from P. pluviosa appears promising as an aid in healing. PMID:26938058

The effects of transcutaneous low-level laser therapy on the skin healing process: an experimental model.

PubMed

Ramos, Felipe Scholz; Maifrino, Laura Beatriz Mesiano; Alves, Sarah; da Costa Aguiar Alves, Beatriz; Perez, Matheus Moreira; Feder, David; Azzalis, Ligia Ajaime; Junqueira, Virginia Berlanga Campos; Fonseca, Fernando Luiz Affonso

2018-01-06

We aim to evaluate the action of transcutaneous laser in the initial wound healing process. The use of low-level laser therapy (LLLT) has proven to be effective on inflammatory modulation and wound healing. The trial was performed on five groups of rats, through a dorsal incision. All groups received treatment on auricular artery. Groups 1 and 3 were treated with transcutaneous LLLT over a period of 15 min. Groups 2 and 4 received one and two inactive laser applications (placebo), respectively. Group 5 was the control one. Blood samples were collected 2 h after the last application of LLLT so that cytokine levels could be measured by ELISA. Tissue fragments were harvested for morphometric, histomorphometric, and RT-qPCR analyses. The morphometric analysis revealed a greater decrease in the wounded area in G1 when compared with G2, whereas in G3, the improvement in the area was greater when compared with G4. Finally, the histomorphometric analysis showed that G1 was the group closer to G5 in terms of collagen fiber count. G2 and G4 had higher amounts of collagen fibers than G5 while G3 had a lower quantity. The use of the transcutaneous LLLT in the current study influenced the wound healing process.

Progress report 3 of cooperative program for design, fabrication, and testing of high modulus composite helicopter shafting

NASA Technical Reports Server (NTRS)

Wright, C. C.; Baker, D. J.

1980-01-01

This report describes the third phase of work, the objective of which was to overcome the excessive brittleness of the previously developed UH-1 helicopter tail rotor drive shaft design which demonstrated a shaft train weight savings of 53.1% over the current 2024-T3 aluminum shaft train. A materials impact program demonstrated exceptionally noteworthy performance of two woven constructions containing E-glass and PRD 49-III (designation later changed to KEVLAR 49) fibers in an epoxy resin matrix. Thermoplastic matrices and PRD 49-III fiber provided impact resistance at low weight which was superior to composites having the same fiber in a thermoset resin matrix. A design, fabrication, and test program showed that shaft impact resistance could be improved over the previously developed graphite composite design at a cost in shaft train rate savings. The shaft train weight savings of the most impact tolerant construction was 4.0% over the current aluminum shaft train. Alternating plies of graphite and glass appear to provide substantially greater tube impact durability than that provided by hybridization of the two fibers into one tape wound to a ply design equivalent in strength and stiffness to that of the alternating ply design. Recommendations were made to continue research work to exploit the potential for more impact-durable structures through the use of KEVLAR 49 fiber, woven structures, thermoplastic matrices and THORNEL 50-S/KEVLAR 49 blends with thermoset matrices.

Electrospun poly(ε-caprolactone) matrices containing silver sulfadiazine complexed with β-cyclodextrin as a new pharmaceutical dosage form to wound healing: preliminary physicochemical and biological evaluation.

PubMed

Souza, Sarah Oliveira Lamas; Cotrim, Monique Alvarenga Pinto; Oréfice, Rodrigo Lambert; Carvalho, Suzana Gonçalves; Dutra, Jessyca Aparecida Paes; de Paula Careta, Francisco; Resende, Juliana Alves; Villanova, Janaina Cecília Oliveira

2018-05-10

Cooperation between researchers in the areas of medical, pharmaceutical and materials science has facilitated the development of pharmaceutical dosage forms that elicit therapeutic effects and protective action with a single product. In addition to optimizing pharmacologic action, such dosage forms provide greater patient comfort and increase success and treatment compliance. In the present work, we prepared semipermeable bioactive electrospun fibers for use as wound dressings containing silver sulfadiazine complexed with β-cyclodextrin in a poly(Ɛ-caprolactone) nanofiber matrix aiming to reduce the direct contact between silver and skin and to modulate the drug release. Wound dressings were prepared by electrospinning, and were subjected to ATR-FT-IR and TG/DTG assays to evaluate drug stability. The hydrophilicity of the fibrous nanostructure in water and PBS buffer was studied by goniometry. Electrospun fibers permeability and swelling capacity were assessed, and a dissolution test was performed. In vitro biological tests were realized to investigate the biological compatibility and antimicrobial activity. We obtained flexible matrices that were each approximately 1.0 g in weight. The electrospun fibers were shown to be semipermeable, with water vapor transmission and swelling indexes compatible with the proposed objective. The hydrophilicity was moderate. Matrices containing pure drug modulated drug release adequately during 24 h but presented a high hemolytic index. Complexation promoted a decrease in the hemolytic index and in the drug release but did not negatively impact antimicrobial activity. The drug was released predominantly by diffusion. These results indicate that electrospun PCL matrices containing β-cyclodextrin/silver sulfadiazine inclusion complexes are a promising pharmaceutical dosage form for wound healing.

Development and Commercialization of an Ideal Mechanical Wound Therapy System

DTIC Science & Technology

2015-12-01

of the research team. The initial proposal called for a series of animal studies to be conducted on domestic pigs . In Phase I, it was readily...neovascularization, fibroblasts, and collagen fibers. There were eosinophilic proteinaceous material present. Inflammation was predominantly comprised of...tissue. Granulation tissue was predominantly comprised of neovascularization, fibroblasts, and collagen fibers. There were eosinophilic proteinaceous

Polysaccharide Fabrication Platforms and Biocompatibility Assessment as Candidate Wound Dressing Materials

PubMed Central

Aduba, Donald C.; Yang, Hu

2017-01-01

Wound dressings are critical for wound care because they provide a physical barrier between the injury site and outside environment, preventing further damage or infection. Wound dressings also manage and even encourage the wound healing process for proper recovery. Polysaccharide biopolymers are slowly becoming popular as modern wound dressings materials because they are naturally derived, highly abundant, inexpensive, absorbent, non-toxic and non-immunogenic. Polysaccharide biopolymers have also been processed into biomimetic platforms that offer a bioactive component in wound dressings that aid the healing process. This review primarily focuses on the fabrication and biocompatibility assessment of polysaccharide materials. Specifically, fabrication platforms such as electrospun fibers and hydrogels, their fabrication considerations and popular polysaccharides such as chitosan, alginate, and hyaluronic acid among emerging options such as arabinoxylan are discussed. A survey of biocompatibility and bioactive molecule release studies, leveraging polysaccharide’s naturally derived properties, is highlighted in the text, while challenges and future directions for wound dressing development using emerging fabrication techniques such as 3D bioprinting are outlined in the conclusion. This paper aims to encourage further investigation and open up new, disruptive avenues for polysaccharides in wound dressing material development. PMID:28952482

Evaluation of LED photobiomodulation on wound healing in hypothyroid and euthyroid rats

NASA Astrophysics Data System (ADS)

Paraguassú, Gardênia Matos; Xavier, Flávia Calo Aquino; Rodriguez, Tânia Tavares; Ramalho, Maria José Pedreira; Pinheiro, Antônio Luiz Barbosa; Ramalho, Luciana Maria Pedreira

2012-09-01

Thyroid hormone deficiency has been associated to disruption of the body's metabolism, including healing process. LED phototherapy has been shown to be effective in improving healing in many situations, but their usefulness in the improvement of hypothyroidism wound healing remains unknown. The aim of this study was to assess histologically the effect of LED (λ630 ± 20nm, 150mW, CW, φ=0.5 cm2, 24J/cm2 per session) on wounds healing in hypothyroid and euthyroid Wistar rats. Standard cutaneous wound (1cm2) was created on the dorsum of 24 animals divided into four groups of 6 animals each: G1: Euthyroid; G2: Euthyroid + LED; G3: Hypothyroid; G4: Hypothyroid + LED. Hypothyroidism was induced in rats with propylthiouracil (0.05g/100mL) administered orally for 4 weeks and maintained until the end of the experiment. The irradiation started immediately after surgery and was repeated every other day for 7 days. Animals were killed 8 days after surgery. The specimens were removed, routinely processed and stained with H&E and Sirius red. Statistical analysis was performed using the Fisher's Test and significance level was 5%. The results of the present investigation showed delayed wounds healing process in hypothyroid rats characterized by incomplete reepithelialization and formation of disorganized collagen fibers (p<0.05) when compared to the euthyroid group, and that in the irradiated groups the reepithelialization was statistically higher when compared with non-irradiated ones (p<0.05). There was improved collagen fibers deposition on irradiated animals (euthyroid and hypothyroid) when compared to non-irradiated ones, but no statistically significant difference (p>0.05). It is concluded that LED light has a positive biomodulative effect on the wound healing process, even when hipothyroidism was present.

Continuous wound infiltration versus epidural analgesia after hepato-pancreato-biliary surgery (POP-UP): a randomised controlled, open-label, non-inferiority trial.

PubMed

Mungroop, Timothy H; Veelo, Denise P; Busch, Olivier R; van Dieren, Susan; van Gulik, Thomas M; Karsten, Tom M; de Castro, Steve M; Godfried, Marc B; Thiel, Bram; Hollmann, Markus W; Lirk, Philipp; Besselink, Marc G

2016-10-01

Epidural analgesia is the international standard for pain treatment in abdominal surgery. Although some studies have advocated continuous wound infiltration with local anaesthetics, robust evidence is lacking, especially on patient-reported outcome measures. We aimed to determine the effectiveness of continuous wound infiltration in hepato-pancreato-biliary surgery. In this randomised controlled, open label, non-inferiority trial (POP-UP), we enrolled adult patients undergoing hepato-pancreato-biliary surgery by subcostal or midline laparotomy in two Dutch hospitals. Patients were centrally randomised (1:1) to receive either pain treatment with continuous wound infiltration using bupivacaine plus patient-controlled analgesia with morphine or to receive (patient-controlled) epidural analgesia with bupivacaine and sufentanil. All patients were treated within an enhanced recovery setting. Randomisation was stratified by centre and type of incision. The primary outcome was the mean Overall Benefit of Analgesic Score (OBAS) from day 1-5, a validated composite endpoint of pain scores, opioid side-effects, and patient satisfaction (range 0 [best] to 28 [worst]). Analysis was per-protocol. The non-inferiority limit of the mean difference was + 3·0. This trial is registered with the Netherlands Trial Registry, number NTR4948. Between Jan 20, 2015, and Sept 16, 2015, we randomly assigned 105 eligible patients: 53 to receive continuous wound infiltration and 52 to receive epidural analgesia. One patient in the continuous wound infiltration group discontinued treatment, as did five in the epidural analgesia group; of these five patients, preoperative placement failed in three (these patients were treated with continuous wound infiltration instead), one patient refused an epidural, and data for the primary endpoint was lost for one. Thus, 55 patients were included in the continuous wound infiltration group and 47 in the epidural analgesia group for the per-protocol analyses. Mean OBAS was 3·8 (SD 2·4) in the continuous wound infiltration group versus 4·4 (2·2) in the epidural group (mean difference -0·62, 95% CI -1·54 to 0·30). Because the upper bound of the one-sided 95% CI did not exceed +3·0, non-inferiority was shown. Four (7%) patients in the continuous wound infiltration group and five (11%) of those in the epidural group had an adverse event. One patient in the continuous wound infiltration group had a serious adverse event (temporary hypotension and arrhythmia after bolus injection); no serious adverse events were noted in the epidural group. These data suggest that continuous wound infiltration is non-inferior to epidural analgesia in hepato-pancreato-biliary surgery within an enhanced recovery setting. Further large-scale trials are required to make a definitive assessment of non-inferiority. Academic Medical Centre, Amsterdam, Netherlands. Copyright © 2016 Elsevier Ltd. All rights reserved.

Variabilities detected by acoustic emission from filament-wound Aramid fiber/epoxy composite pressure vessels

NASA Technical Reports Server (NTRS)

Hamstad, M. A.

1978-01-01

Two hundred and fifty Aramid fiber/epoxy pressure vessels were filament-wound over spherical aluminum mandrels under controlled conditions typical for advanced filament-winding. A random set of 30 vessels was proof-tested to 74% of the expected burst pressure; acoustic emission data were obtained during the proof test. A specially designed fixture was used to permit in situ calibration of the acoustic emission system for each vessel by the fracture of a 4-mm length of pencil lead (0.3 mm in diameter) which was in contact with the vessel. Acoustic emission signatures obtained during testing showed larger than expected variabilities in the mechanical damage done during the proof tests. To date, identification of the cause of these variabilities has not been determined.

Design of an elastin-layered dermal regeneration template.

PubMed

Mithieux, Suzanne M; Weiss, Anthony S

2017-04-01

We demonstrate a novel approach for the production of tunable quantities of elastic fibers. We also show that exogenous tropoelastin is rate-limiting for elastin synthesis regardless of the age of the dermal fibroblast donor. Additionally, we provide a strategy to further enhance synthesis by older cells through the application of conditioned media. We show that this approach delivers an elastin layer on one side of the leading dermal repair template for contact with the deep dermis in order to deliver prefabricated elastic fibers to a physiologically appropriate site during subsequent surgery. This system is attractive because it provides for the first time a viable path for sufficient, histologically detectable levels of patient elastin into full-thickness wound sites that have until now lacked this elastic underlayer. The scars of full thickness wounds typically lack elasticity. Elastin is essential for skin elasticity and is enriched in the deep dermis. This paper is significant because it shows that: (1) we can generate elastic fibers in tunable quantities, (2) tropoelastin is the rate-limiting component in elastin synthesis in vitro, (3) we can generate elastin fibers regardless of donor age, (4) we describe a novel approach to further increase the numbers and thickness of elastic fibers for older donors, (5) we improve on Integra Dermal Regeneration Template and generate a new hybrid biomaterial intended to subsequently surgically deliver these elastic fibers, (6) the elastic fiber layer is presented on the side of Integra that is intended for delivery into its physiologically appropriate site i.e. the deep dermis. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Wound healing and protease inhibition activity of Bacoside-A, isolated from Bacopa monnieri wettest.

PubMed

Sharath, R; Harish, B G; Krishna, V; Sathyanarayana, B N; Swamy, H M Kumara

2010-08-01

Bacopa monnieri (L.) Wettest. (Scrophulariaceae) is a well-known medicinal herb. In the Indian system of medicine it is known as Brahmi (Sanskrit) and Indian water hyssop. Methanolic extract of Bacopa monnieri and its isolated constituent Bacoside-A were screened for wound healing activity. Bacoside-A was screened for wound healing activity by excision, incision and dead space wound on Swiss albino rats. Significant wound healing activity was observed in both extract and the Bacoside-A treated groups. The SDS-PAGE caseinolytic zymogram analysis of inhibition of matrix metalloproteases (MMPs) enzyme from the excision wound by Bacoside-A, an isolated constituent, was done with the concentrations 100 and 200 micromg/ml. In Bacoside-A treated groups, epithelialization of the excision wound was faster with a high rate (18.30 +/- 0.01 days) of wound contraction. The tensile strength of the incision wound was increased (538.47 +/- 0.14 g) in the Bacoside-A treated group. In the dead space wound model, the weight of the granuloma was also increased (89.15 +/- 0.08 g). The histological examination of the granuloma tissue of the Bacoside-A treated group showed increased cross-linking of collagen fibers and absence of monocytes. The wound healing activity of Bacoside-A was more effective in various wound models compared to the standard skin ointment Nitrofurazone.

Iodoform gauze removes necrotic tissue from pressure ulcer wounds by fibrinolytic activity.

PubMed

Mizokami, Fumihiro; Murasawa, Yusuke; Furuta, Katsunori; Isogai, Zenzo

2012-01-01

Iodoform gauze is used in clinical practice for treatment of infected wounds. However, effectiveness and action mechanism of iodoform gauze for removal of necrotic tissue are unknown. We therefore employed case control and biochemical studies in order to clarify the pharmacological activity of iodoform gauze. A clinical study demonstrated that treatment with iodoform gauze removed necrotic tissue more effectively than treatment with conventional ointments. More than 60% of iodoform gauze-treated wounds were completely debrided within 2 weeks. Consistent with the clinical observation, biochemical analyses revealed clear differences in wound fluid proteins after treatment with iodoform gauze or conventional gauze. The amount of macroaggregates of type I collagen from wounds were remarkably decreased in iodoform gauze. Moreover, iodoform gauze and iodoform itself released non-aggregative type I collagen from necrotic debris in vitro. Taken together, we conclude that iodoform gauze efficiently removes necrotic tissue by its lytic activity for collagen fibers.

Simulated impact damage in a thick graphite/epoxy laminate using spherical indenters

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1988-01-01

A study was made to determine the extent of fiber damage caused by low-velocity impact of spherical impactors to a very thick graphite/epoxy laminate. The laminate was cut from a filament wound case being developed for the Space Shuttle solid rocket motors. The case was wound using a wet process with AS4W graphite fiber and HBRF-55A epoxy. Impacts were simulated under quasi-static conditions by pressing hemispherically shaped indenters against the laminate at different locations. The contact force and indenter diameter were varied from location to location. The forces were chosen for each indenter diameter to produce contact pressures below and above that required to initiate damage. After the forces were applied, the laminate was cut into smaller pieces so that each piece contained a test site. The pieces were then deplied and the individual plies examined to determine the extent of fiber damage. Broken fibers were found in the outer layers directly beneath the contact site. The locus of broken fibers in each layer resembled a crack normal to the direction of the fibers. The maximum length and depth of the cracks increased with increasing contact pressure and indenter diameter. The internal stresses in the laminate were calculated using Hertz's law and Love's solution for pressure applied on part of the boundary of a semi-infinite body. The maximum length and depth of the cracks were predicted using a maximum shear stress criterion. Predictions and measurements were in good agreement.

Keratinocyte response to immobilized growth factors for enhanced dermal wound healing

NASA Astrophysics Data System (ADS)

Stefonek-Puccinelli, Tracy Jane

Chronic wounds cost billions of dollars per year to treat and wound care is limited to ineffective and/or expensive options. Chronic wounds are characterized by a failure to reepithelialize, as well as deficiencies in growth factors, such as epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1), normally present during wound healing. Our system described herein begins to tackle the problems associated with designing bioactive materials for chronic wound healing applications. We show that we can induce accelerated keratinocyte migration with photo-immobilized EGF and further control migration speed through the culture of cells on different types of gradient patterns of EGF. We also successfully immobilized IGF-1 while retaining its bioactivity, and further showed it induces directed keratinocyte migration, although not as potently as immobilized EGF. Potential synergy between co-immobilized IGF-1 and EGF was also investigated, although EGF continued to dominate the cellular response, and no significant increase in cell migration was achieved via the addition of IGF-1 to the system. To further understand cellular response to our immobilized growth factors, we investigated keratinocyte signaling and function in response to changes in EGF presentation. It was found that immobilized and soluble EGF can play different, yet complementary, roles in regulating keratinocyte function. Specifically, keratinocytes responded to immobilized EGF with high EGF receptor (EGFR) activation, accompanied by low proliferation and high migratory activity. In contrast, keratinocytes treated with soluble EGF displayed a highly proliferative, rather than migratory, phenotype. We then transitioned our photo-immobilization techniques to materials that may be more suitable as a wound dressing, such as silk fibroin films. Silk fibroin is a natural fiber with many desirable qualities for a biomaterial including high strength and elasticity, biocompatibility, a beta-keratin structure which closely mimics human keratin, and ease of fabrication and modification. These silk films can also provide topographical cues via simple cast molding of any feature on the micron scale. This system allowed simultaneous presentation of topographic cues, inhibitory and/or synergistic, with our chemotactic cues. Our preliminary data suggest keratinocytes remain viable on silk fibroin films, and that these films can be patterned with immobilized EGF to induce keratinocyte migration.

Structural Health Monitoring of Composite Wound Pressure Vessels

NASA Technical Reports Server (NTRS)

Grant, Joseph; Kaul, Raj; Taylor, Scott; Jackson, Kurt; Myers, George; Sharma, A.

2002-01-01

The increasing use of advanced composite materials in the wide range of applications including Space Structures is a great impetus to the development of smart materials. Incorporating these FBG sensors for monitoring the integrity of structures during their life cycle will provide valuable information about viability of the usage of such material. The use of these sensors by surface bonding or embedding in this composite will measure internal strain and temperature, and hence the integrity of the assembled engineering structures. This paper focuses on such a structure, called a composite wound pressure vessel. This vessel was fabricated from the composite material: TRH50 (a Mitsubishi carbon fiber with a 710-ksi tensile strength and a 37 Msi modulus) impregnated with an epoxy resin from NEWPORT composites (WDE-3D-1). This epoxy resin in water dispersed system without any solvents and it cures in the 240-310 degrees F range. This is a toughened resin system specifically designed for pressure applications. These materials are a natural fit for fiber sensors since the polyimide outer buffer coating of fiber can be integrated into the polymer matrix of the composite material with negligible residual stress. The tank was wound with two helical patterns and 4 hoop wraps. The order of winding is: two hoops, two helical and two hoops. The wall thickness of the composite should be about 80 mil or less. The tank should burst near 3,000 psi or less. We can measure the actual wall thickness by ultrasonic or we can burst the tank and measure the pieces. Figure 1 shows a cylinder fabricated out of carbon-epoxy composite material. The strain in different directions is measured with a surface bonded fiber Bragg gratings and with embedded fiber Bragg gratings as the cylinder is pressurized to burst pressures. Figure 2 shows the strain as a function of pressure of carbon-epoxy cylinder as it is pressurized with water. Strain is measured in different directions by multiple gratings oriented in both axial and hoops directions.

Enhanced healing of mitomycin C-treated healing-impaired wounds in rats with hydrosheets composed of chitin/chitosan, fucoidan, and alginate as wound dressings.

PubMed

Murakami, Kaoru; Ishihara, Masayuki; Aoki, Hiroshi; Nakamura, Shingo; Nakamura, Shin-Ichiro; Yanagibayashi, Satoshi; Takikawa, Megumi; Kishimoto, Satoko; Yokoe, Hidetaka; Kiyosawa, Tomoharu; Sato, Yasunori

2010-01-01

To create a moist environment for rapid wound healing, a hydrosheet composed of alginate, chitin/chitosan, and fucoidan (ACF-HS) has been developed as a functional wound dressing. The aim of this study was to evaluate the accelerating effect of ACF-HS on wound healing for rat mitomycin C-treated healing-impaired wounds. Full-thickness skin defects were made on the back of rats and mitomycin C was applied onto the wound for 10 minutes to prepare a healing-impaired wound. After thoroughly washing out the mitomycin C, ACF-HS was applied to the healing-impaired wounds. The rats were later euthanized and histological sections of the wounds were prepared. The histological examinations showed significantly advanced granulation tissue and capillary formations in the healing-impaired wounds treated with ACF-HS on days 7 and 14, in comparison with that in alginate fiber (Kaltostat), hydrogel wound dressing (DuoACTIVE), and nontreatment (negative control). Furthermore, in cell culture studies, ACF-HS-absorbed serum and fibroblast growth factor-2 was found to be proliferative for fibroblasts and endothelial cells, respectively, and ACF-HS-absorbed serum was found to be chemoattractive for fibroblasts. However, our results may not be strictly comparable with general healing-impaired wound models in humans because of the cell damage by mitomycin C. In addition, more biocompatibility studies of fucoidan are essential due to the possibility of renal toxicity. © 2010 by the Wound Healing Society.

Clostridium septicum myositis in a western lowland gorilla (Gorilla gorilla gorilla).

PubMed

Fontenot, Deidre K; Terrell, Scott P; Miller, Michele; Robbins, Patricia K; Stetter, Mark; Weber, Martha

2005-09-01

A 10-yr-old male gorilla (Gorilla gorilla gorilla) with a history of conspecific bite wounds was evaluated for acute onset of depression, anorexia, and right hemiparesis. The animal was immobilized for diagnostic examination and treatment for suspected toxic shock from a necrotizing, emphysematous wound infection, but was euthanized due to complications during recovery. Gross and histopathologic examination revealed acute necrotizing myositis, fasciitis, cellulitis, and emphysema in the affected wound area, with large numbers of large Gram-positive rods among necrotic muscle fibers. Severe pulmonary edema with airways containing fibrin, acute hemorrhage in multiple body sites, thrombosis in blood vessels in the skeletal muscle, liver, and lung, and lymph node hyperplasia with lymphoid necrosis and hemorrhage. Immunohistochemical fluorescent antibody staining of muscle from the wound site was positive for

Non-contact continuous-wave diffuse optical tomographic system to capture vascular dynamics in the foot

NASA Astrophysics Data System (ADS)

Hoi, Jennifer W.; Kim, Hyun K.; Khalil, Michael A.; Fong, Christopher J.; Marone, Alessandro; Shrikhande, Gautam; Hielscher, Andreas H.

2015-03-01

Dynamic optical tomographic imaging has shown promise in diagnosing and monitoring peripheral arterial disease (PAD), which affects 8 to 12 million in the United States. PAD is the narrowing of the arteries that supply blood to the lower extremities. Prolonged reduced blood flow to the foot leads to ulcers and gangrene, which makes placement of optical fibers for contact-based optical tomography systems difficult and cumbersome. Since many diabetic PAD patients have foot wounds, a non-contact interface is highly desirable. We present a novel non-contact dynamic continuous-wave optical tomographic imaging system that images the vasculature in the foot for evaluating PAD. The system images at up to 1Hz by delivering 2 wavelengths of light to the top of the foot at up to 20 source positions through collimated source fibers. Transmitted light is collected with an electron multiplying charge couple device (EMCCD) camera. We demonstrate that the system can resolve absorbers at various locations in a phantom study and show the system's first clinical 3D images of total hemoglobin changes in the foot during venous occlusion at the thigh. Our initial results indicate that this system is effective in capturing the vascular dynamics within the foot and can be used to diagnose and monitor treatment of PAD in diabetic patients.

The Histopathological Investigation of Red and Blue Light Emitting Diode on Treating Skin Wounds in Japanese Big-Ear White Rabbit

PubMed Central

Xu, Yanfeng; Han, Yunlin; Jiang, Binbin; Huang, Lan; Zhu, Hua; Xu, Yuhuan; Yang, Weiling; Qin, Chuan

2016-01-01

The biological effects of different wavelengths of light emitting diode (LED) light tend to vary from each other. Research into use of photobiomodulation for treatment of skin wounds and the underlying mechanisms has been largely lacking. We explored the histopathological basis of the therapeutic effect of photobiomodulation and the relation between duration of exposure and photobiomodulation effect of different wavelengths of LED in a Japanese big-ear white rabbit skin-wound model. Skin wound model was established in 16 rabbits (three wounds per rabbit: one served as control, the other two wounds were irradiated by red and blue LED lights, respectively). Rabbits were then divided into 2 equal groups based on the duration of exposure to LED lights (15 and 30 min/exposure). The number of wounds that showed healing and the percentage of healed wound area were recorded. Histopathological examination and skin expression levels of fibroblast growth factor (FGF), epidermal growth factor (EGF), endothelial marker (CD31), proliferating cell nuclear antigen (Ki67) and macrophagocyte (CD68) infiltration, and the proliferation of skin collagen fibers was assessed. On days 16 and 17 of irradiation, the healing rates in red (15 min and 30 min) and blue (15 min and 30 min) groups were 50%, 37.5%, 25% and 37.5%, respectively, while the healing rate in the control group was 12.5%. The percentage healed area in the red light groups was significantly higher than those in other groups. Collagen fiber and skin thickness were significantly increased in both red light groups; expression of EGF, FGF, CD31 and Ki67 in the red light groups was significantly higher than those in other groups; the expression of FGF in red (30 min) group was not significantly different from that in the blue light and control groups. The effect of blue light on wound healing was poorer than that of red light. Red light appeared to hasten wound healing by promoting fibrous tissue, epidermal and endothelial cell proliferation. An increase in the exposure time to 30 min did not confer any additional benefit in both red and blue light groups. This study provides a theoretical basis for the potential therapeutic application of LED light in clinical settings. PMID:27347879

Novel bilayer wound dressing based on electrospun gelatin/keratin nanofibrous mats for skin wound repair.

PubMed

Yao, Chun-Hsu; Lee, Chia-Yu; Huang, Chiung-Hua; Chen, Yueh-Sheng; Chen, Kuo-Yu

2017-10-01

A bilayer membrane (GKU) with a commercial polyurethane wound dressing as an outer layer and electrospun gelatin/keratin nanofibrous mat as an inner layer was fabricated as a novel wound dressing. Scanning electron micrographs showed that gelatin/keratin nanofibers had a uniform morphology and bead-free structure with average fiber diameter of 160.4nm. 3-(4,5-Dimethylthiazolyl)-2,5-diphenyltetrazolium bromide assay using L929 fibroblast cells indicated that the residues released from the gelatin/keratin composite nanofibrous mat accelerated cell proliferation. Cell attachment experiments revealed that adhered cells spread better and migrated deeper into the gelatin/keratin nanofibrous mat than that into the gelatin nanofibrous mat. In animal studies, compared with the bilayer membrane without keratin, gauze and commercial wound dressing, Comfeel®, GKU membrane gave much more number of blood vessels and a greater reduction in wound area at 4days, and better wound repair at 14days with a thicker epidermis and larger number of newly formed hair follicles. GKU membrane, thus, could be a good candidate for wound dressing applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Wound healing activity of the inflorescence of Typha elephantina (Cattail).

PubMed

Panda, Vandana; Thakur, Tejas

2014-03-01

Methanolic extracts of Typha elephantina inflorescence (TE) and its bandage were screened for wound healing by incision and excision wound models in Wistar rats. In the incision wound model, incision wounds were topically treated with TE gel (2.0% [w/w], 3.0% [w/w], and 5.0% [w/w]), Typha elephantina inflorescence bandage, and the reference standard 5.0% w/w povidone iodine for a period of 10 days. When the wounds healed thoroughly, sutures were removed on the 8th postwounding day, and the tensile strength of the skin was measured on the 10th day. In the excision wound model, excision wounds were treated with TE gel (3.0% [w/w] and 5.0% [w/w]), inflorescence bandage, and 5.0% w/w povidone iodine till the wounds completely healed. Epithelization time, wound contraction, hydroxyproline and hexosamine content of the scab, and ascorbic acid and malondialdehyde content of the plasma were determined in this model. In the incision wound model, high tensile strength of the skin of the healed wound was observed in rats treated with the TE gels and the inflorescence bandage when compared with wounded control rats. The increase in tensile strength indicates a promotion of collagen fibers and a firm knitting of the disrupted wound surfaces by collagen. In the excision wound model, higher rate of wound contraction, decreased period of epithelization, elevated hydroxyproline, hexosamine, and ascorbic acid levels, and a significant decrease in malondialdehyde content was observed in treated groups when compared with the wounded control animals. It may be concluded that the inflorescence of Typha elephantina possesses a potent wound healing activity, which may be due to an underlying antioxidant mechanism.

Wound-Healing Peptides for Treatment of Chronic Diabetic Foot Ulcers and Other Infected Skin Injuries.

PubMed

Gomes, Ana; Teixeira, Cátia; Ferraz, Ricardo; Prudêncio, Cristina; Gomes, Paula

2017-10-18

As the incidence of diabetes continues to increase in the western world, the prevalence of chronic wounds related to this condition continues to be a major focus of wound care research. Additionally, over 50% of chronic wounds exhibit signs and symptoms that are consistent with localized bacterial biofilms underlying severe infections that contribute to tissue destruction, delayed wound-healing and other serious complications. Most current biomedical approaches for advanced wound care aim at providing antimicrobial protection to the open wound together with a matrix scaffold (often collagen-based) to boost reestablishment of the skin tissue. Therefore, the present review is focused on the efforts that have been made over the past years to find peptides possessing wound-healing properties, towards the development of new and effective wound care treatments for diabetic foot ulcers and other skin and soft tissue infections.

Continuous wound infusion and local infiltration analgesia for postoperative pain and rehabilitation after total hip arthroplasty.

PubMed

Fusco, Pierfrancesco; Cofini, Vincenza; Petrucci, Emiliano; Scimia, Paolo; Fiorenzi, Maurizio; Paladini, Giuseppe; Behr, Astrid U; Borghi, Battista; Flamini, Stefano; Pizzoferrato, Renzo; Colafarina, Olivo; Di Francesco, Alexander; Tabacco, Tito; Necozione, Stefano; Marinangeli, Franco

2018-05-01

Total hip arthroplasty is one of the most common procedures in orthopedic surgery. We hypothesized that local infiltration of analgesia and continuous wound infusion of anesthetics in the first 72 hours after surgery could provide more effective postoperative analgesia with better rehabilitation. A double-blind, randomized, controlled study was conducted with 96 patients who underwent total hip arthroplasty. The patients were randomized to receive either a local infiltration analgesia and continuous wound infusion of anesthetics or a local infiltration analgesia and continuous wound infusion of saline solution. The patients in both groups received subarachnoid anesthesia and a local infiltration analgesia. A multihole catheter was placed next to the implant and connected to an electronic pump containing a 300-mL solution of 0.2% levobupivacaine (experimental group) or saline (control group). A total of 96 consecutive patients were enrolled and randomized. Of these, 48 patients received local infiltration analgesia and continuous wound infusion of local anesthetics, and the remainder received local infiltration analgesia and continuous wound infusion of saline solution. The analysis showed a significant main effect of treatment on the postoperative incident of pain (Ftreat(1,93)=22.62, P=0.000) and on resting pain during the post-surgery follow-up (Ftreat(1,93)=15.62, P=0.0002). The pain scores during the rehabilitation period were significantly less in the experimental group. Analgesic consumption was less in the experimental group. The addition of continuous wound infusion of anesthetics to local infiltration analgesia provided an extended analgesic effect associated with good rehabilitation performance.

Nanotopography guides and directs cell migration in amoeboid and epithelial cells

NASA Astrophysics Data System (ADS)

Lee, Rachel; Das, Satarupa; Hourwitz, Matthew; Sun, Xiaoyu; Parent, Carole; Fourkas, John; Losert, Wolfgang

Cell migration plays a critical role in development, angiogenesis, immune response, wound healing, and cancer metastasis. In many cases, cells also move in the context of a matrix of collagen fibers, and the alignment of these fibers can both affect the migration phenotype and guide cells. Here we show that both fast and slow migrating cells - amoeboid HL-60 and epithelial MCF10A - are affected in similar ways by micro/nanostructures with dimensions similar to those of collagen fibers. Cell alignment enhances the efficiency of migration by increasing directional persistence.

Potential Use of Essential Oil Isolated from Cleistocalyx operculatus Leaves as a Topical Dermatological Agent for Treatment of Burn Wound

PubMed Central

Le, Nghia-Thu Tram; Dam, Sao-Mai

2018-01-01

Several herbal remedies have been used as topical agents to cure burn wound, one of the most common injuries in worldwide. In this study, we investigated the potential use of Cleistocalyx operculatus essential oil to treat the burn wound. We identified a total of 13 bioactive compounds of essential oil, several of which exhibited the anti-inflammatory and antimicrobial activities. Furthermore, the essential oil showed the antibacterial effect against S. aureus but not with P. aeruginosa. The supportive effect of essential oil on burn wound healing process also has been proven. Among three groups of mice, wound contraction rate of essential oil treated group (100%) was significantly higher than tamanu oil treated (79%) and control mice (71%) after 20 days (0.22 ± 0.03 versus 0.31 ± 0.02 cm2, resp., p < 0.05). Histological studies revealed that burn wounds treated with essential oil formed a complete epidermal structure, thick and neatly arranged fibers, and scattered immune cells in burn wound. On the contrary, saline treated burn wound formed uneven epidermal layer with necrotic ulcer, infiltration of immune cells, and existence of granulation tissue. This finding demonstrated Cleistocalyx operculatus essential oil as promising topical dermatological agent to treat burn wound. PMID:29692805

Potential Use of Essential Oil Isolated from Cleistocalyx operculatus Leaves as a Topical Dermatological Agent for Treatment of Burn Wound.

PubMed

Tran, Gia-Buu; Le, Nghia-Thu Tram; Dam, Sao-Mai

2018-01-01

Several herbal remedies have been used as topical agents to cure burn wound, one of the most common injuries in worldwide. In this study, we investigated the potential use of Cleistocalyx operculatus essential oil to treat the burn wound. We identified a total of 13 bioactive compounds of essential oil, several of which exhibited the anti-inflammatory and antimicrobial activities. Furthermore, the essential oil showed the antibacterial effect against S. aureus but not with P. aeruginosa. The supportive effect of essential oil on burn wound healing process also has been proven. Among three groups of mice, wound contraction rate of essential oil treated group (100%) was significantly higher than tamanu oil treated (79%) and control mice (71%) after 20 days (0.22 ± 0.03 versus 0.31 ± 0.02 cm 2 , resp., p < 0.05). Histological studies revealed that burn wounds treated with essential oil formed a complete epidermal structure, thick and neatly arranged fibers, and scattered immune cells in burn wound. On the contrary, saline treated burn wound formed uneven epidermal layer with necrotic ulcer, infiltration of immune cells, and existence of granulation tissue. This finding demonstrated Cleistocalyx operculatus essential oil as promising topical dermatological agent to treat burn wound.

The effect of He-Ne and Ga-Al-As lasers on the healing of oral mucosa in diabetic mice.

PubMed

Fahimipour, Farahnaz; Houshmand, Behzad; Alemi, Parvin; Asnaashari, Mohammad; Tafti, Mahmoud Akhavan; Akhoundikharanagh, Fatemeh; Farashah, Seyed Emadeddin Najafi; Aminisharifabad, Mohammad; Korani, Aghdas Setoudehnia; Mahdian, Mina; Bastami, Farshid; Tahriri, Mohammadreza

2016-06-01

Delayed wound healing is one of the complications of diabetes mellitus. Low-level laser therapy (LLLT) has been used to accelerate wound healing however the effect of LLLT on the hard palate wound healing in streptozotocin-induced diabetic (STZ-D) mice has not yet been characterized. This study aims to determine the effect of LLLT (He-Ne and Ga-Al-As laser) on the process of wound healing in the hard palate among diabetic and non-diabetic mice. 90 adult male mice were divided into six groups. Type 1 diabetes mellitus was induced in three groups by means of injection of STZ. Of these, one group was irradiated with He-Ne laser (DH group), one with Ga-Al-As laser (DG group) and one did not undergo any LLLT (DC group). The remaining groups were non-diabetic which were allotted to laser therapy with He-Ne laser (NH group) or with Ga-Al-As laser (NG group) or no LLLT (NC group). Five animals from each group were killed on the third, seventh, and fourteenth days after surgery, and biopsies were made for histological analysis. On the 3rd and 7th days after the surgery, the number of polymorphonuclear (PMN) cells in NH, DH, NG, and DG groups was significantly lower than that of the control groups. On the 3rd, 7th and 14th days, the fibroblasts and new blood vessel counts and collagen fibers in diabetic laser treated groups (DG and DH) were significantly higher compared to that of NC, DC, NH and NG groups. On the 7th and 14th days, the fibroblasts and new blood vessel counts and collagen fibers in NH, DH, NG, and DG groups were also significantly higher than that of the control groups, and the fibroblast and new blood vessel counts and collagen density fibers in NH and DH groups were higher than that of the NG and DG groups. LLLT with He-Ne laser compared to Ga-Al-As laser has a positive healing effect on hard palate gingival wounds in STZ-D mice. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of graphite/epoxy cases for orbit insertion motors

NASA Technical Reports Server (NTRS)

Schmidt, W. W.

1973-01-01

The fabrication procedures are described for filament-wound rocket motor cases, approximately 26.25 inches long by 25.50 inches diameter, utilizing graphite fibers. The process utilized prepreg tape which consists of Fortafil 4-R fibers in the E-759 epoxy resin matrix. This fabrication effect demonstrated an ability to fabricate high quality graphite/epoxy rocket motor cases in the 26.25 inch by 25.50 inch size range.

Repeated Use of Immersive Virtual Reality Therapy to Control Pain during Wound Dressing Changes in Pediatric and Adult Burn Patients

PubMed Central

Faber, Albertus W.; Patterson, David R.; Bremer, Marco

2012-01-01

Objective The current study explored whether immersive virtual reality continues to reduce pain (via distraction) during more than one wound care session per patient. Patients: Thirty six patients aged 8 to 57 years (mean age of 27.7 years), with an average of 8.4% total body surface area burned (range .25 to 25.5 TBSA) received bandage changes, and wound cleaning. Methods Each patient received one baseline wound cleaning/debridement session with no-VR (control condition) followed by one or more (up to seven) subsequent wound care sessions during VR. After each wound care session (one session per day), worst pain intensity was measured using a Visual Analogue Thermometer (VAT), the dependent variable. Using a within subjects design, worst pain intensity VAT during wound care with no-VR (baseline, Day 0) was compared to pain during wound care while using immersive virtual reality (up to seven days of wound care during VR). Results Compared to pain during no-VR Baseline (Day 0), pain ratings during wound debridement were statistically lower when patients were in virtual reality on Days 1, 2 and 3, and although not significant beyond day 3, the pattern of results from Days 4, 5, and 6 are consistent with the notion that VR continues to reduce pain when used repeatedly. Conclusions Results from the present study suggest that VR continues to be effective when used for three (or possibly more) treatments during severe burn wound debridement. PMID:23970314

Pressure vessel with improved impact resistance and method of making the same

NASA Technical Reports Server (NTRS)

DeLay, Thomas K. (Inventor); Patterson, James E. (Inventor); Olson, Michael A. (Inventor)

2010-01-01

A composite overwrapped pressure vessel is provided which includes a composite overwrapping material including fibers disposed in a resin matrix. At least first and second kinds of fibers are used. These fibers typically have characteristics of high strength and high toughness to provide impact resistance with increased pressure handling capability and low weight. The fibers are applied to form a pressure vessel using wrapping or winding techniques with winding angles varied for specific performance characteristics. The fibers of different kinds are dispersed in a single layer of winding or wound in distinct separate layers. Layers of fabric comprised of such fibers are interspersed between windings for added strength or impact resistance. The weight percentages of the high toughness and high strength materials are varied to provide specified impact resistance characteristics. The resin matrix is formed with prepregnated fibers or through wet winding. The vessels are formed with or without liners.

Establishment of a cell-based wound healing assay for bio-relevant testing of wound therapeutics.

PubMed

Planz, Viktoria; Wang, Jing; Windbergs, Maike

Predictive in vitro testing of novel wound therapeutics requires adequate cell-based bio-assays. Such assays represent an integral part during preclinical development as pre-step before entering in vivo studies. Simple "scratch tests" based on defected skin cell monolayers exist, however these can solely be used for testing liquids, as cell monolayer destruction and excessive hydration limit their applicability for (semi-)solid systems like wound dressings. In this context, a cell-based wound healing assay is introduced for rapid and predictive testing of wound therapeutics independent of their physical state in a bio-relevant environment. A novel wound healing assay was established for bio-relevant and predictive testing of (semi-) solid wound therapeutics. The assay allows for physiologically relevant hydration of the tested wound therapeutics at the air-liquid interface and their removal without cell monolayer disruption. In a proof-of-concept study, the applicability and discriminative power could be demonstrated by examining unloaded and drug-loaded wound dressings with two different established wound healing actives (dexpanthenol and metyrapone) and their effect on skin cell behavior. The influence of the released drug on the cells´ healing behavior could successfully be monitored over time. Wound size assessment after 96h resulted in an eight fold smaller wound area for drug treated models compared to the ones treated with unloaded fibers and non-treated wounds. This assay provides valuable first insights towards the establishment of a valid screening and evaluation tool for preclinical wound therapeutic development from liquid to (semi-)solid systems to improve predictability in a simple, yet standardized way. Copyright © 2017 Elsevier Inc. All rights reserved.

Low velocity gunshot wounds result in significant contamination regardless of ballistic characteristics.

PubMed

Weinstein, Joseph; Putney, Emily; Egol, Kenneth

2014-01-01

Controversy exists among the orthopedic community regarding the treatment of gunshot injuries. No consistent treatment algorithm exists for treatment of low energy gunshot wound (GSW) trauma. The purpose of this study was to critically examine the wound contamination following low velocity GSW based upon bullet caliber and clothing fiber type found within the injury track. Four types of handguns were fired at ballistic gel from a 10-foot distance. Various clothing materials were applied (denim, cotton, polyester, and wool) circumferentially around the tissue agar in a loose manor. A total of 32 specimens were examined. Each caliber handgun was fired a minimum of 5 times into a gel. Regardless of bullet caliber there was gross contamination of the entire bullet track in 100% of specimens in all scenarios and for all fiber types. Furthermore, as would be expected, the degree of contamination appeared to increase as the size of the bullet increased. Low velocity GSWs result in significant contamination regardless of bullet caliber and jacket type. Based upon our results further investigation of low velocity GSW tracks is warranted. Further clinical investigation should focus on the degree to which debridement should be undertaken.

Impaired Laparotomy Wound Healing in Obese Rats

PubMed Central

Xing, Liyu; Culbertson, Eric J.; Wen, Yuan; Robson, Martin C.

2015-01-01

Background Obesity increases the risk of laparotomy dehiscence and incisional hernia. The aim of this study was to measure the biological effect of obesity on laparotomy wound healing and the formation of incisional hernias. Methods Normal-weight Sprague–Dawley (SD) and obese Zucker rats were used in an established laparotomy wound healing and incisional ventral hernia model. Mechanical testing was performed on abdominal wall strips collected from laparotomy wounds. Hernia size was measured by digital imaging. Picrosirius staining for collagen isoforms was observed with polarized microscopy. Abdominal wall fibroblasts were cultured to measure collagen matrix remodeling and proliferation. Results Laparotomy wound healing was significantly impaired in obese rats. Mechanical strength was lower than in normal-weight rats. Yield load was reduced in the obese group at all time points. Picrosirius red staining showed increased immature type III collagen content and disorganized type I collagen fibers within laparotomy wounds of obese rats. Wound size was significantly larger in the obese group. Collagen matrix remodeling was impaired with fibroblasts from obese rats, but there was no difference in fibroblast proliferation between the obese and normal-weight groups. Conclusions We observed for the first time that laparotomy wound healing is impaired in obese rats. The recovery of laparotomy wound strength is delayed due to abnormal collagen maturation and remodeling, possibly due to a defect in fibroblast function. Strategies to improve outcomes for laparotomy wound healing in obese patients should include correcting the wound healing defect, possibly with growth factor or cell therapy. PMID:21347822

Filamin A Mediates Wound Closure by Promoting Elastic Deformation and Maintenance of Tension in the Collagen Matrix

PubMed Central

Mohammadi, Hamid; Pinto, Vanessa I.; Wang, Yongqiang; Hinz, Boris; Janmey, Paul A.; McCulloch, Christopher A.

2016-01-01

Cell-mediated remodeling and wound closure are critical for efficient wound healing, but the contribution of actin-binding proteins to contraction of the extracellular matrix is not defined. We examined the role of filamin A (FLNa), an actin filament cross-linking protein, in wound contraction and maintenance of matrix tension. Conditional deletion of FLNa in fibroblasts in mice was associated with ~ 4 day delay of full-thickness skin wound contraction compared with wild-type (WT) mice. We modeled the healing wound matrix using cultured fibroblasts plated on grid-supported collagen gels that create lateral boundaries, which are analogues to wound margins. In contrast to WT cells, FLNa knockdown (KD) cells could not completely maintain tension when matrix compaction was resisted by boundaries, which manifested as relaxed matrix tension. Similarly, WT cells on cross-linked collagen, which requires higher levels of sustained tension, exhibited approximately fivefold larger deformation fields and approximately twofold greater fiber alignment compared with FLNa KD cells. Maintenance of boundary-resisted tension markedly influenced the elongation of cell extensions: in WT cells, the number (~50%) and length (~300%) of cell extensions were greater than FLNa KD cells. We conclude that FLNa is required for wound contraction, in part by enabling elastic deformation and maintenance of tension in the matrix. PMID:26134946

Effects of Angelica dahurica and Rheum officinale Extracts on Excisional Wound Healing in Rats

PubMed Central

Yang, Wan-Ting; Ke, Chun-Yen; Harn, Horng-Jyh

2017-01-01

The main objective of wound treatments is to restore the functional skin properties and prevent infection. Traditional Chinese medicine provides alternative anti-inflammatory, antimicrobial, and wound healing therapies. Both Angelica dahurica extract (AE) and Rheum officinale extract (RE) possess antimicrobial activity. In this study, AE and RE were applied in wound treatment to investigate their healing effects. Thirty Sprague-Dawley rats with dorsal full-thickness skin excision were divided into normal saline (NS), AE, RE, AE plus RE (ARE), and Biomycin (BM) groups. The treatment and area measurement of wounds were applied daily for 21 days. Wound biopsies and blood samples were obtained for histology examinations and cytokine analysis. Results showed that wound contraction in ARE group was significantly higher than that in NS and BM groups (P < 0.05). Histological analysis showed that more inflammatory cell infiltration, collagen fibers, and myofibroblasts were observed in ARE treated group than those in NS group on days 3–5. In ARE group, plasma IL-6 levels were elevated during days 3–5 (P > 0.05), and plasma TGF-β1 levels were significantly lower than those in the NS group on days 3-4 (P < 0.05). In conclusion, ARE accelerates wound healing during inflammation and proliferation phases. PMID:28900458

Synthesis of Novel Derivatives of Quinazoline Schiff base Compound Promotes Epithelial Wound Healing.

PubMed

Bagheri, Elham; Saremi, Kamelia; Hajiaghaalipour, Fatemeh; Faraj, Fadhil Lafta; Ali, Hapipah Mohd; Abdulla, Mahmood Ameen; Khaing, Si Lay; Salehen, Nur'Ain

2018-01-30

Quinazoline is an aromatic bicyclic compound exhibiting several pharmaceutical and biological activities. This study was conducted to investigate the potential wound healing properties of synthetic quinazoline compound (SQC) on experimental rats. The toxicity of SQC was determined by MTT cell proliferation assay. The healing effect of SQC was assessed by in vitro wound healing scratch assay on the skin fibroblast cells (BJ-5ta) and in vivo wound healing experiment of low and high dose of SQC on adult Sprague-Dawley rats compared with negative (gum acacia) and positive control (Intrasite-gel). Hematoxylin and eosin (H&E), Masson's trichrome (MT) staining and immunohistochemistry analysis were performed to evaluate the histopathological alterations and proteins expression of Bax and Hsp70 on the wound tissue after 10 days. In addition, levels of antioxidant enzymes (catalase, glutathione peroxidase and superoxide dismutase), and malondialdehyde (MDA) were measured in wound tissue homogenates. The SQC significantly enhanced BJ-5ta cell proliferation and accelerated the percentage of wound closure, with less scarring, increased fibroblast and collagen fibers and less inflammatory cells compared with the negative control. The compound also increases endogenous enzymes and decline lipid peroxidation in wound homogenate. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Delayed cutaneous wound healing in aged rats compared to younger ones.

PubMed

Soybir, Onur C; Gürdal, Sibel Ö; Oran, Ebru Ş; Tülübaş, Feti; Yüksel, Meral; Akyıldız, Ayşenur İ; Bilir, Ayhan; Soybir, Gürsel R

2012-10-01

Delayed wound healing in elderly males is a complex process in which the factors responsible are not fully understood. This study investigated the hormonal, oxidative and angiogenic factors affecting wound healing in aged rats. Two groups consisting of eight healthy male Wistar Albino rats [young (30 ± 7 days) and aged (360 ± 30 days)], and a cutaneous incision wound healing model were used. Scar tissue samples from wounds on the 7th, 14th and 21st days of healing were evaluated for hydroxyproline and vascular endothelial growth factor content. Macrophage, lymphocyte, fibroblast and polymorphonuclear cell infiltration; collagen formation and vascularization were assessed by light and electron microscopy. The free oxygen radical content of the wounds was measured by a chemiluminescence method. Blood sample analysis showed that the hydroxyproline and total testosterone levels were significantly higher, and the oxygen radical content was significantly lower in young rats. Histopathological, immunohistochemical and ultrastructural evaluations revealed higher amounts of fibroblasts and collagen fibers, and more vascularization in young rats. These results are indicative of the delayed wound healing in aged rats. A combination of multiple factors including hormonal regulation, free oxygen radicals and impaired angiogenesis appears to be the cause of delayed cutaneous healing. © 2011 The Authors. International Wound Journal © 2011 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

Pressure Vessel with Impact and Fire Resistant Coating and Method of Making Same

NASA Technical Reports Server (NTRS)

DeLay, Thomas K. (Inventor)

2005-01-01

An impact and fire resistant coating laminate is provided which serves as an outer protective coating for a pressure vessel such as a composite overwrapped vessel with a metal lining. The laminate comprises a plurality of fibers (e.g., jute twine or other, stronger fibers) which are wound around the pressure vessel and an epoxy matrix resin for the fibers. The epoxy matrix resin including a plurality of microspheres containing a temperature responsive phase change material which changes phase in response to exposure thereof to a predetermined temperature increase so as to afford increased insulation and hear absorption.

Pressure vessel with impact and fire resistant coating and method of making same

NASA Technical Reports Server (NTRS)

DeLay, Thomas K. (Inventor)

2005-01-01

An impact and fire resistant coating laminate is provided which serves as an outer protective coating for a pressure vessel such as a composite overwrapped vessel with a metal lining. The laminate comprises a plurality of fibers (e.g., jute twine or other, stronger fibers) which are wound around the pressure vessel and an epoxy matrix resin for the fibers. The epoxy matrix resin including a plurality of microspheres containing a temperature responsive phase change material which changes phase in response to exposure thereof to a predetermined temperature increase so as to afford increased insulation and heat absorption.

Nanofibers made of globular proteins.

PubMed

Dror, Yael; Ziv, Tamar; Makarov, Vadim; Wolf, Hila; Admon, Arie; Zussman, Eyal

2008-10-01

Strong nanofibers composed entirely of a model globular protein, namely, bovine serum albumin (BSA), were produced by electrospinning directly from a BSA solution without the use of chemical cross-linkers. Control of the spinnability and the mechanical properties of the produced nanofibers was achieved by manipulating the protein conformation, protein aggregation, and intra/intermolecular disulfide bonds exchange. In this manner, a low-viscosity globular protein solution could be modified into a polymer-like spinnable solution and easily spun into fibers whose mechanical properties were as good as those of natural fibers made of fibrous protein. We demonstrate here that newly formed disulfide bonds (intra/intermolecular) have a dominant role in both the formation of the nanofibers and in providing them with superior mechanical properties. Our approach to engineer proteins into biocompatible fibrous structures may be used in a wide range of biomedical applications such as suturing, wound dressing, and wound closure.

Effects of a polysaccharide nanogel-crosslinked membrane on wound healing.

PubMed

Maeda, Hiroki; Kobayashi, Hiroshi; Miyahara, Takayuki; Hashimoto, Yoshihide; Akiyoshi, Kazunari; Kasugai, Shohei

2017-04-01

Wound-dressing materials that promote wound healing while protecting wounds from infections are advantageous for clinical applications. Hence, we developed a cholesterol-bearing pullulan (CHP) nanogel that stimulated wound healing; however, it was mechanically weak and difficult to handle. Thus, the purpose of this study was to examine precisely the effects of a mechanically reinforced nanogel-crosslinked (NanoClik) membrane on wound healing. NanoClik was prepared by mixing a thiol-terminated polyethylene glycol solution and an acryloyl group-modified CHP nanogel solution. A thin silicone sheet membrane, which was combined with NanoClik, was prepared. The NanoClick membranes and both positive and negative control membranes (collagen combined with silicone membrane and silicone membrane alone, respectively) were tested in vivo using a dorsal skin defect rat model. The rate and extent of wound healing was compared between groups after 7 and 14 days of implantation. In the NanoClik membrane group, the wound area was significantly reduced and neoepithelialization was promoted, compared with that observed in the other groups. In addition, extension and accumulation of collagen fibers were evident in the NanoClik membrane group. The NanoClik membrane is a strong candidate for use as an effective and safe wound-dressing material. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 544-550, 2017. © 2015 Wiley Periodicals, Inc.

Relationship between apposition pressure during welding and tensile strength of the acute weld

NASA Astrophysics Data System (ADS)

Wu, Paul J.; Walsh, Joseph T., Jr.

2001-05-01

Dye-assisted photothermal welding is a technique used to close wounds by thermally cross-linking collagen across apposed tissue edges. For a successful weld, not only do laser parameters have to be optimized, but also apposition of the incision has to be consistent and controlled. The objective of this study was to quantify the relationship between the applied apposition pressure (i.e., the compressive force holding the wound closed during the welding procedure divided by the area of the skin-to-skin interface) and the tensile strength of the wound following the welding procedure. By using a clamping device made of two complementary pieces, each 3 cm wide with a row of 10 equally spaced blunt wire mesh tips, the apposition pressure along a 2-cm-long incision in each albino guinea pig was quantified using a 127-micrometers -thick load cell and varied from 0-1.8 kgf/cm2. A continuous wave, Nd:YAG laser emitting 10.0 W of 1.06-micrometers radiation from a 600-micrometers -diameter fiber irradiating a 5-mm-diameter spot size was scanned across the incision in order to deliver 300 J of total energy. As the apposition pressure of the incisions was increased, the resulting tensile strength of welded skin increased in a sigmoidal manner. For this welding technique, an apposition pressure of at least 1.2 kgf/cm2 is necessary to obtain maximum weld strength of the skin (2.56+/- 0.36 kg/cm2).

Carbon fiber composites for cryogenic filament-wound vessels

NASA Technical Reports Server (NTRS)

Larsen, J. V.; Simon, R. A.

1972-01-01

Advanced unidirectional and bidirectional carbon fiber/epoxy resin composites were evaluated for physical and mechanical properties over a cryogenic to room temperature range for potential application to cryogenic vessels. The results showed that Courtaulds HTS carbon fiber was the superior fiber in terms of cryogenic strength properties in epoxy composites. Of the resin systems tested in ring composites, CTBN/ERLB 4617 exhibited the highest composite strengths at cryogenic temperatures, but very low interlaminar shear strengths at room temperature. Tests of unidirectional and bidirectional composite bars showed that the Epon 828/Empol 1040 resin was better at all test temperatures. Neither fatigue cycling nor thermal shock had a significant effect on composite strengths or moduli. Thermal expansion measurements gave negative values in the fiber direction and positive values in the transverse direction of the composites.

Characterization and antibacterial properties of porous fibers containing silver ions

NASA Astrophysics Data System (ADS)

Sun, Zhaoyang; Fan, Chenxu; Tang, Xiaopeng; Zhao, Jianghui; Song, Yanhua; Shao, Zhongbiao; Xu, Lan

2016-11-01

Materials prepared on the base of bioactive silver compounds have become more and more popular. In the present work, the surface morphology, structure and properties, of electrospun Polylactide Polylactic acid (PLA) porous fibers containing various ratios of silver ions were investigated by a combination of X-ray photoelectron spectroscopy (XPS), universal testing machine, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and et al. The biological activities of the proposed porous fibers were discussed in view of the released silver ions concentration. Antibacterial properties of these porous fibers were studied using two bacterial strains: Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA). Results of the antibacterial testing suggested that PLA porous fibers containing silver ions could be used as potent antibacterial wound dressing materials in the biomedical field.

Composite Nozzle/Thrust Chambers Analyzed for Low-Cost Boosters

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

1999-01-01

The Low Cost Booster Technology Program is an initiative to minimize the cost of future liquid engines by using advanced materials and innovative designs, and by reducing engine complexity. NASA Marshall Space Flight Center s 60K FASTRAC Engine is one example where these design philosophies have been put into practice. This engine burns a liquid kerosene/oxygen mixture. It uses a one-piece, polymer composite thrust chamber/nozzle that is constructed of a tape-wrapped silica phenolic liner, a metallic injector interface ring, and a filament-wound epoxy overwrap. A cooperative effort between NASA Lewis Research Center s Structures Division and Marshall is underway to perform a finite element analysis of the FASTRAC chamber/nozzle under all the loading and environmental conditions that it will experience during its lifetime. The chamber/nozzle is a complex composite structure. Of its three different materials, the two composite components have distinctly different fiber architectures and, consequently, require separate material model descriptions. Since the liner is tape wrapped, it is orthotropic in the nozzle global coordinates; and since the overwrap is filament wound, it is treated as a monoclinic material. Furthermore, the wind angle on the overwrap varies continuously along the length of the chamber/nozzle.

Hydrogel Microencapsulated Insulin-Secreting Cells Increase Keratinocyte Migration, Epidermal Thickness, Collagen Fiber Density, and Wound Closure in a Diabetic Mouse Model of Wound Healing.

PubMed

Aijaz, Ayesha; Faulknor, Renea; Berthiaume, François; Olabisi, Ronke M

2015-11-01

Wound healing is a hierarchical process of intracellular and intercellular signaling. Insulin is a potent chemoattractant and mitogen for cells involved in wound healing. Insulin's potential to promote keratinocyte growth and stimulate collagen synthesis in fibroblasts is well described. However, there currently lacks an appropriate delivery mechanism capable of consistently supplying a wound environment with insulin; current approaches require repeated applications of insulin, which increase the chances of infecting the wound. In this study, we present a novel cell-based therapy that delivers insulin to the wound area in a constant or glucose-dependent manner by encapsulating insulin-secreting cells in nonimmunogenic poly(ethylene glycol) diacrylate (PEGDA) hydrogel microspheres. We evaluated cell viability and insulin secretory characteristics of microencapsulated cells. Glucose stimulation studies verified free diffusion of glucose and insulin through the microspheres, while no statistical difference in insulin secretion was observed between cells in microspheres and cells in monolayers. Scratch assays demonstrated accelerated keratinocyte migration in vitro when treated with microencapsulated cells. In excisional wounds on the dorsa of diabetic mice, microencapsulated RIN-m cells accelerated wound closure by postoperative day 7; a statistically significant increase over AtT-20ins-treated and control groups. Histological results indicated significantly greater epidermal thickness in both microencapsulated RIN-m and AtT-20ins-treated wounds. The results suggest that microencapsulation enables insulin-secreting cells to persist long enough at the wound site for a therapeutic effect and thereby functions as an effective delivery vehicle to accelerate wound healing.

Does rat granulation tissue maturation involve gap junction communications?

PubMed

Au, Katherine; Ehrlich, H Paul

2007-07-01

Wound healing, a coordinated process, proceeds by sequential changes in cell differentiation and terminates with the deposition of a new connective tissue matrix, a scar. Initially, there is the migratory fibroblast, followed by the proliferative fibroblast, then the synthetic fibroblast, which transforms into the myofibroblast, and finally the apoptotic fibroblast. Gap junction intercellular communications are proposed to coordinate the stringent control of fibroblast phenotypic changes. Does added oleamide, a natural fatty acid that blocks gap junction intercellular communications, alter the phenotypic progression of wound fibroblasts? Pairs of polyvinyl alcohol sponges attached to Alzet pumps, which constantly pumped either oleamide or vehicle solvent, were implanted subcutaneously into three rats. On day 8, implants were harvested and evaluated histologically and biochemically. The capsule of oleamide-treated sponge contained closely packed fibroblasts with little connective tissue between them. The birefringence intensity of that connective tissue was reduced, indicating a reduced density of collagen fiber bundles. Myofibroblasts, identified immunohistologically by alpha-smooth muscle actin-stained stress fibers, were reduced in oleamide-treated implants. Western blot analysis showing less alpha-smooth muscle actin confirmed the reduced density of myofibroblasts. It appears that oleamide retards the progression of wound repair, where less connective tissue is deposited, the collagen is less organized, and the appearance of myofibroblasts is impaired. These findings support the hypothesis that gap junction intercellular communications between wound fibroblasts in granulation tissue play a role in the progression of repair and the maturation of granulation tissue into scar.

Multimodal imaging of cutaneous wound tissue

NASA Astrophysics Data System (ADS)

Zhang, Shiwu; Gnyawali, Surya; Huang, Jiwei; Ren, Wenqi; Gordillo, Gayle; Sen, Chandan K.; Xu, Ronald

2015-01-01

Quantitative assessment of wound tissue ischemia, perfusion, and inflammation provides critical information for appropriate detection, staging, and treatment of chronic wounds. However, few methods are available for simultaneous assessment of these tissue parameters in a noninvasive and quantitative fashion. We integrated hyperspectral, laser speckle, and thermographic imaging modalities in a single-experimental setup for multimodal assessment of tissue oxygenation, perfusion, and inflammation characteristics. Algorithms were developed for appropriate coregistration between wound images acquired by different imaging modalities at different times. The multimodal wound imaging system was validated in an occlusion experiment, where oxygenation and perfusion maps of a healthy subject's upper extremity were continuously monitored during a postocclusive reactive hyperemia procedure and compared with standard measurements. The system was also tested in a clinical trial where a wound of three millimeters in diameter was introduced on a healthy subject's lower extremity and the healing process was continuously monitored. Our in vivo experiments demonstrated the clinical feasibility of multimodal cutaneous wound imaging.

Computational and Experimental Study of the Mechanics of Embryonic Wound Healing

PubMed Central

Varner, Victor D.; Taber, Larry A.

2013-01-01

Wounds in the embryo show a remarkable ability to heal quickly without leaving a scar. Previous studies have found that an actomyosin ring (“purse string”) forms around the wound perimeter and contracts to close the wound over the course of several dozens of minutes. Here, we report experiments that reveal an even faster mechanism which remarkably closes wounds by more than 50% within the first 30 seconds. Circular and elliptical wounds (~100 µm in size) were made in the blastoderm of early chick embryos and allowed to heal, with wound area and shape characterized as functions of time. The closure rate displayed a biphasic behavior, with rapid constriction lasting about a minute, followed by a period of more gradual closure to complete healing. Fluorescent staining suggests that both healing phases are driven by actomyosin contraction, with relatively rapid contraction of fibers at cell borders within a relatively thick ring of tissue (several cells wide) around the wound followed by slower contraction of a thin supracellular actomyosin ring along the margin, consistent with a purse string mechanism. Finite-element modeling showed that this idea is biophysically plausible, with relatively isotropic contraction within the thick ring giving way to tangential contraction in the thin ring. In addition, consistent with experimental results, simulated elliptical wounds heal with little change in aspect ratio, and decreased membrane tension can cause these wounds to open briefly before going on to heal. These results provide new insight into the healing mechanism in embryonic epithelia. PMID:23973771

Enhanced antibacterial nanocomposite mats by coaxial electrospinning of polycaprolactone fibers loaded with Zn-based nanoparticles.

PubMed

Prado-Prone, Gina; Silva-Bermudez, Phaedra; Almaguer-Flores, Argelia; García-Macedo, Jorge A; García, Victor I; Rodil, Sandra E; Ibarra, Clemente; Velasquillo, Cristina

2018-04-16

ZnO and Zn acetate nanoparticles were embedded in polycaprolactone coaxial-fibers and uniaxial-fibers matrices to develop potential antibacterial nanocomposite wound dressings (mats). Morphology, composition, wettability, crystallinity and fiber structure of mats were characterized. Antibacterial properties of mats were tested against E. coli and S. aureus by turbidity and MTT assays. The effect of UVA illumination (prior to bacteria inoculation) on mats' antibacterial activity was also studied. Results showed that a coaxial-fibers design maintained nanoparticles distributed in the outer-shell of fibers and, in general, enhanced the antibacterial effect of the mats, in comparison to conventional uniaxial-fibers mats. Results indicated that mats simultaneously inhibited planktonic and biofilm bacterial growth by, probably, two main antibacterial mechanisms; 1) release of Zn 2+ ions (mainly from Zn acetate nanoparticles) and 2) photocatalytic oxidative processes exerted by ZnO nanoparticles. Antibacterial properties of mats were significantly improved by coaxial-fibers design and exposure to UVA-light prior to bacteria inoculation. Copyright © 2018 Elsevier Inc. All rights reserved.

Early cessation of pressure garment therapy results in scar contraction and thickening

PubMed Central

DeBruler, Danielle M.; Zbinden, Jacob C.; Baumann, Molly E.; Blackstone, Britani N.; Malara, Megan M.; Bailey, J. Kevin

2018-01-01

Pressure garment therapy is often prescribed to improve scar properties following full-thickness burn injuries. Pressure garment therapy is generally recommended for long periods of time following injury (1–2 years), though it is plagued by extremely low patient compliance. The goal of this study was to examine the effects of early cessation of pressure garment therapy on scar properties. Full-thickness burn injuries were created along the dorsum of red Duroc pigs. The burn eschar was excised and wound sites autografted with split-thickness skin. Scars were treated with pressure garments within 1 week of injury and pressure was maintained for either 29 weeks (continuous pressure) or for 17 weeks followed by cessation of pressure for an additional 12 weeks (pressure released); scars receiving no treatment served as controls. Scars that underwent pressure garment therapy were significantly smoother and less contracted with decreased scar height compared to control scars at 17 weeks. These benefits were maintained in the continuous pressure group until week 29. In the pressure released group, grafts significantly contracted and became more raised, harder and rougher after the therapy was discontinued. Pressure cessation also resulted in large changes in collagen fiber orientation and increases in collagen fiber thickness. The results suggest that pressure garment therapy effectively improves scar properties following severe burn injury; however, early cessation of the therapy results in substantial loss of these improvements. PMID:29897933

Early cessation of pressure garment therapy results in scar contraction and thickening.

PubMed

DeBruler, Danielle M; Zbinden, Jacob C; Baumann, Molly E; Blackstone, Britani N; Malara, Megan M; Bailey, J Kevin; Supp, Dorothy M; Powell, Heather M

2018-01-01

Pressure garment therapy is often prescribed to improve scar properties following full-thickness burn injuries. Pressure garment therapy is generally recommended for long periods of time following injury (1-2 years), though it is plagued by extremely low patient compliance. The goal of this study was to examine the effects of early cessation of pressure garment therapy on scar properties. Full-thickness burn injuries were created along the dorsum of red Duroc pigs. The burn eschar was excised and wound sites autografted with split-thickness skin. Scars were treated with pressure garments within 1 week of injury and pressure was maintained for either 29 weeks (continuous pressure) or for 17 weeks followed by cessation of pressure for an additional 12 weeks (pressure released); scars receiving no treatment served as controls. Scars that underwent pressure garment therapy were significantly smoother and less contracted with decreased scar height compared to control scars at 17 weeks. These benefits were maintained in the continuous pressure group until week 29. In the pressure released group, grafts significantly contracted and became more raised, harder and rougher after the therapy was discontinued. Pressure cessation also resulted in large changes in collagen fiber orientation and increases in collagen fiber thickness. The results suggest that pressure garment therapy effectively improves scar properties following severe burn injury; however, early cessation of the therapy results in substantial loss of these improvements.

[Study of collagen and elastic fibers of connective tissue in patients with and without primary inguinal hernia].

PubMed

Bórquez, Pablo; Garrido, Luis; Manterola, Carlos; Peña, Patricio; Schlageter, Carol; Orellana, Juan José; Ulloa, Hugo; Peña, Juan Luis

2003-11-01

There are few studies looking for collagen matrix defects in patients with inguinal bernia. To study the skin connective tissue in patients with and without inguinal bernia. Skin from the surgical wound was obtained from 23 patients with and 23 patients without inguinal bernia. The samples were processed for conventional light microscopy. Collagen fibers were stained with Van Giesson and elastic fibers with Weigert stain. Patients without hernia had compact collagen tracts homogeneously distributed towards the deep dermis. In contrast, patients with hernia had zones in the dermis with thinner and disaggregated collagen tracts. Connective tissue had a lax aspect in these patients. Collagen fiber density was 52% lower in patients with hernia, compared to subjects without hernia. No differences in elastic fiber density or distribution was observed between groups. Patients with inguinal bernia have alterations in skin collagen fiber quality and density.

Ex-vivo multiphoton analysis of rabbit corneal wound healing following photorefractive keratectomy

NASA Astrophysics Data System (ADS)

Wang, Tsung-Jen; Lo, Wen; Dong, Chen-Yuan; Hu, Fung-Rong

2008-02-01

The aim of this study is to assess the application of multiphoton autofluorescence and second harmonic generation (SHG) microscopy for investigating corneal wound healing after high myopic (-10.0D) photorefractive keratectomy (PRK) procedures on the rabbit eyes. The effect of PRK on the morphology and distribution of keratocytes were investigated using multiphoton excited autofluorescence imaging, while the effect of PRK on the arrangement of collagen fibers was monitored by second-harmonic generation imaging. Without histological processing, multiphoton microscopy is able to characterize corneal damage and wound healing from PRK. Our results show that this technique has potential application in the clinical evaluation of corneal damage due to refractive surgery, and may be used to study the unwanted side effects of these procedures.

Using Gene Transcription Patterns (Bar Coding Scans) to Guide Wound Debridement and Healing

PubMed Central

Tomic-Canic, Marjana; Ayello, Elizabeth A.; Stojadinovic, Olivera; Golinko, Michael S.; Brem, Harold

2010-01-01

PURPOSE To acquaint wound care practitioners with new information related to debridement of chronic wounds. TARGET AUDIENCE This continuing education activity is intended for physicians and nurses with an interest in wound care. OBJECTIVES After reading this article and taking this test, the reader should be able to: Explain the role of keratinocytes in wound healing. Discuss new research findings on the physiological differences between healing and nonhealing wounds. Identify implications of the new research for debridement of chronic wounds. PMID:18836328

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

21 CFR 878.4410 - Low energy ultrasound wound cleaner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Low energy ultrasound wound cleaner. 878.4410... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4410 Low energy ultrasound wound cleaner. (a) Identification. A low energy ultrasound wound cleaner is a device that uses...

Novel nanofibrous dressings containing rhEGF and Aloe vera for wound healing applications.

PubMed

Garcia-Orue, Itxaso; Gainza, Garazi; Gutierrez, Franciso Borja; Aguirre, Jose Javier; Evora, Carmen; Pedraz, Jose Luis; Hernandez, Rosa Maria; Delgado, Araceli; Igartua, Manoli

2017-05-25

Nanofibrous membranes produced by electrospinning possess a large surface area-to-volume ratio, which mimics the three-dimensional structure of the extracellular matrix. Thus, nanofibrous dressings are a promising alternative for chronic wound healing, since they can replace the natural ECM until it is repaired. Therefore, in this study we have developed a PLGA nanofibrous membrane that contains recombinant human Epidermal Growth Factor (rhEGF) and Aloe vera (AV) extract. Both of them promote wound healing, as EGF is a wound healing mediator and AV stimulates the proliferation and activity of fibroblast. The obtained membranes were composed of uniform and randomly oriented fibers with an average diameter of 356.03±112.05nm, they presented a porosity of 87.92±11.96% and the amount of rhEGF was 9.76±1.75μg/mg. The in vitro viability assay demonstrated that the membranes containing rhEGF and AV improved fibroblast proliferation, revealing the beneficial effect of the combination. Furthermore, these membranes accelerated significantly wound closure and reepithelisation in an in vivo full thickness wound healing assay carried out in db/db mice. Overall, these findings demonstrated the potential of PLGA nanofibers containing rhEGF and AV for the treatment of chronic wounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Moderate treadmill running exercise prior to tendon injury enhances wound healing in aging rats

PubMed Central

Zhang, Jianying; Yuan, Ting; Wang, James H-C.

2016-01-01

The effect of exercise on wound healing in aging tendon was tested using a rat moderate treadmill running (MTR) model. The rats were divided into an MTR group that ran on a treadmill for 4 weeks and a control group that remained in cages. After MTR, a window defect was created in the patellar tendons of all rats and wound healing was analyzed. We found that MTR accelerated wound healing by promoting quicker closure of wounds, improving the organization of collagen fibers, and decreasing senescent cells in the wounded tendons when compared to the cage control. MTR also lowered vascularization, increased the numbers of tendon stem/progenitor cells (TSCs) and TSC proliferation than the control. Besides, MTR significantly increased the expression of stem cell markers, OCT-4 and Nanog, and tenocyte genes, Collagen I, Collagen III and tenomodulin, and down-regulated PPAR-γ, Collagen II and Runx-2 (non-tenocyte genes). These findings indicated that moderate exercise enhances healing of injuries in aging tendons through TSC based mechanisms, through which exercise regulates beneficial effects in tendons. This study reveals that appropriate exercise may be used in clinics to enhance tendon healing in aging patients. PMID:26885754

Moderate treadmill running exercise prior to tendon injury enhances wound healing in aging rats.

PubMed

Zhang, Jianying; Yuan, Ting; Wang, James H-C

2016-02-23

The effect of exercise on wound healing in aging tendon was tested using a rat moderate treadmill running (MTR) model. The rats were divided into an MTR group that ran on a treadmill for 4 weeks and a control group that remained in cages. After MTR, a window defect was created in the patellar tendons of all rats and wound healing was analyzed. We found that MTR accelerated wound healing by promoting quicker closure of wounds, improving the organization of collagen fibers, and decreasing senescent cells in the wounded tendons when compared to the cage control. MTR also lowered vascularization, increased the numbers of tendon stem/progenitor cells (TSCs) and TSC proliferation than the control. Besides, MTR significantly increased the expression of stem cell markers, OCT-4 and Nanog, and tenocyte genes, Collagen I, Collagen III and tenomodulin, and down-regulated PPAR-γ, Collagen II and Runx-2 (non-tenocyte genes). These findings indicated that moderate exercise enhances healing of injuries in aging tendons through TSC based mechanisms, through which exercise regulates beneficial effects in tendons. This study reveals that appropriate exercise may be used in clinics to enhance tendon healing in aging patients.

Fiber gasket and method of making same

DOEpatents

Bruck, Gerald Joseph; Alvin, Mary Anne; Smeltzer, Eugene E.

2003-01-01

A gasket (1) is made by repetitively spirally winding a fiber (3) back on itself in a closed path. The gasket (1) so made has a multi-layer spiral winding (1) formed in a loop (5). The fiber (3) can be wound at a constant wrap rate to form a gasket with a uniform cross-section around the loop. Alternatively, the wrap rate can be varied, increased to increase cross-sectional bulk, and decreased to reduce cross-section bulk around the loop (5). Also, the spiral winding (7) can be applied over a core (13) of either strands of the fiber (3) or a dissimilar material providing a desired property such as resiliency, stiffness or others. For high temperature applications, a ceramic fiber (3) can be used. The gasket (1) can have any of various geometric configurations with or without a core (13).

Raman probing of molecular interactions of alginate biopolymers with cells

NASA Astrophysics Data System (ADS)

Chourpa, Igor; Carpentier, Philippe; Maingault, Philippe; Fetissoff, Franck; Dubois, Pierre

2000-05-01

The biological polymers extracted from brown algae, alginates, are novel materials in biotechnology and biomedicine. Their ability to form viscous gels is used to immobilize or encapsulate yeast, enzymes, living cells and drugs. Calcium-alginate fibers are extensively used in wound dressings since exhibit antihaemostatic and healing properties. The problem with alginate-made dressings in surgery is their slow biodegradability: if entrapped within tissues, they can induce a local cellular recruitment with an inflammatory response contemporaneous to the resorption phase. In part, this problem is a consequence of poor solubility of the calcium alginates in water. Although calcium alginate fibers can exchange calcium ions with sodium ions from the wound exudate to create a calcium/sodium alginate fibers, the residual alginates are thought to be not totally degradable in vivo. Rapid and non- destructive characterization of series of the crude alginates and calcium alginate fibers has been performed using Raman spectroscopy with near IR excitation. Study of structural organization of the polymeric chains within calcium alginate fibers have been previously reported as made by confocal Raman multispectral imaging (CRMSI) in visible. Here, the Raman approach has been used to monitor the ion exchange reactions for different types of alginates and their salts in vitro. For in vivo evaluation, histological sections of alginate-treated rat tissue have been analyzed by light microscopy and CRMSI. The in vitro Raman modeling and the histochemical mapping were a necessary precursor for application of the Raman microprobe to follow in a non-invasive way the alginate-cell molecular interactions in rat tissue.

In Vitro Evaluation and Mechanism Analysis of the Fiber Shedding Property of Textile Pile Debridement Materials

PubMed Central

Fu, Yijun; Xie, Qixue; Lao, Jihong; Wang, Lu

2016-01-01

Fiber shedding is a critical problem in biomedical textile debridement materials, which leads to infection and impairs wound healing. In this work, single fiber pull-out test was proposed as an in vitro evaluation for the fiber shedding property of a textile pile debridement material. Samples with different structural design (pile densities, numbers of ground yarns and coating times) were prepared and estimated under this testing method. Results show that single fiber pull-out test offers an appropriate in vitro evaluation for the fiber shedding property of textile pile debridement materials. Pull-out force for samples without back-coating exhibited a slight escalating trend with the supplement in pile density and number of ground yarn plies, while back-coating process significantly raised the single fiber pull-out force. For fiber shedding mechanism analysis, typical pull-out behavior and failure modes of the single fiber pull-out test were analyzed in detail. Three failure modes were found in this study, i.e., fiber slippage, coating point rupture and fiber breakage. In summary, to obtain samples with desirable fiber shedding property, fabric structural design, preparation process and raw materials selection should be taken into full consideration. PMID:28773428

Unripe Musa sapientum peel in the healing of surgical wounds in rats.

PubMed

Atzingen, Dênia Amélia Novato Castelli Von; Gragnani, Alfredo; Veiga, Daniela Francescato; Abla, Luis Eduardo Felipe; Cardoso, Lorraine Lorene Felix; Ricardo, Thiago; Mendonça, Adriana Rodrigues dos Anjos; Ferreira, Lydia Masako

2013-01-01

To assess the effects of unripe Musa sapientum peel on the healing of surgical wounds in rats. One hundred and twenty Wistar rats were divided into two treatment groups of 60 animals each: the control group (gel without the active ingredient) and experimental group (4% Musa sapientum peel gel). A 4 x 4 cm surgical wound was created on the back of each animal. The wound was cleaned daily with 0.9% saline, treated with 4% gel or natrosol gel (control), and covered with gauze. Animals from both groups were sacrificed after seven, 14 and 21 days of treatment; the tissue from the wound site was removed together with a margin of normal skin for histological analysis. No significant differences in wound contraction rates (p=0.982) were found between time points (seven, 14 and 21 days of treatment) in both groups. However, a significantly higher wound contraction rate was observed in the control group on day 21 compared with the experimental group (p=0.029). There were no significant differences in histomorphological features between groups. The experimental group showed an increased number of polymorphonuclear cells on day 7, with a significant reduction on day 21 (p=0.026). The use of 4% unripe Musa sapientum peel gel on surgical wounds in rats resulted in an increased number of polymorphonuclear cells on day 7, reduced wound contraction, reduced vascular proliferation and increased concentration of collagen fibers on day 21.

Generation of an artificial skin construct containing a non-degradable fiber mesh: a potential transcutaneous interface

PubMed Central

Cahn, Frederick; Kyriakides, Themis R

2009-01-01

Generation of a stable interface between soft tissues and biomaterials could improve the function of transcutaneous prostheses, primarily by minimizing chronic infections. We hypothesized that inclusion of non-biodegradable biomaterials in an artificial skin substrate would improve integration of the neodermis. In the present study, we compared the biocompatibility of an experimental substrate, consisting of collagen and glycosylaminoglycans, with commercially available artificial skin of similar composition. By utilizing a mouse excisional wound model, we found that the source of collagen (bovine tendon versus hide), extent of injury and wound contraction were critical determinants of inflammation and neodermis formation. Reducing the extent of injury to underlying muscle reduced inflammation and improved remodeling; the improved conditions allowed the detection of a pro-inflammatory effect of hide-derived collagen. To eliminate the complication of wound contraction, subsequent grafts were performed in guinea pigs and showed that inclusion of carbon fibers or non-degradable sutures resulted in increased foreign body response (FBR) and altered remodeling. On the other hand, inclusion of a polyester multi-stranded mesh induced a mild FBR and allowed normal neodermis formation. Taken together, our observations suggest that non-degradable biomaterials can be embedded in an artificial skin construct without compromising its ability to induce neodermis formation. PMID:18689926

Time-Temperature Dependent Response of Filament Wound Composites for Flywheel Rotors

NASA Technical Reports Server (NTRS)

Thesken, John C.; Bowman, Cheryl L.; Arnold, Steven M.; Thompson, Richard C.

2004-01-01

Flywheel energy storage offers an attractive alternative to battery systems used in space applications such as the International Space Station. Rotor designs capable of high specific energies benefit from the load carrying capacity of hoop wound carbon fibers but their long-term durability may be limited by time-temperature dependent radial deformations. This was investigated for the carbon/epoxy rotor material, IM7/8552. Coupon specimens were sectioned from filament wound panels. These were tested in compression and tension at room temperature (RT), 95 and 135 C for strain rates from 5x10(exp -6) per second to 5x10(exp -3) per second. Time, temperature and load sign dependent effects were significant transverse to the fiber. At -0.5 percent strain for 72 hr, compressive stresses relaxed 16.4 percent at 135 C and 13 percent at 95 C. Tensile stresses relaxed only 7 percent in 72 hr at 135 C for 0.5 percent strain. Using linear hereditary material response and Boltzmann s principle of superposition to describe this behavior is problematic if not intractable. Micromechanics analysis including the effects of processing residual stresses is needed to resolve the paradoxes. Uniaxial compressive stress relaxation data may be used to bound the loss of radial pre-load stresses in flywheel rotors.

Topical effects of frog "Rana ridibunda" skin secretions on wound healing and reduction of wound microbial load.

PubMed

Mashreghi, Mohammad; Rezazade Bazaz, Mahere; Mahdavi Shahri, Nasser; Asoodeh, Ahmad; Mashreghi, Mansour; Behnam Rassouli, Morteza; Golmohammadzadeh, Shiva

2013-02-13

Study of the interrelationships between human and the animals in their environment has always been a subject of interest and caused discoveries of the animal applications in medicine. From the latest century, these remedies called back in traditional medicine of Vietnam and South America and frog skin was used as a biological dressing and had good effects in healing wounds. Also, frog skin secretions have wound healing properties and reduce inflammation. In this study we applied these secretions in the form of ointment to investigate their healing activities. Skin secretions were extracted from Rana ridibunda to evaluate their effects on wound healing in mice. Secretion used as raw extract (RE) and ultrafiltrated extract, using a membrane with cutoff 10kDa as under 10kDa (U10E), was administrated as ointment every 48h on wound site. Control group was left without any treatment and also there was other group treated with ointment (O group) alone. On 2, 4 and 6 days post injury, animals were euthanized and images were taken for wound closure evaluation. Then wound locations were removed for histological assays. Also wound microbial load was examined. Observational parameters including wound closure and wound microbiology in experimental groups compared with the control and O groups have been studied. The results showed U10E group has better effects than RE, O and control groups. Histological parameters, including numbers of inflammatory and fibroblast cells and amount of collagen fibers, neovascularization, as well, represented greater degree of wound healing in U10E group compared with RE, O, and control groups. Our results showed that frog skin secretions were significantly effective in promoting wound healing process. The U10E extract from the frog R. ridibunda possesses a potent accelerating wound healing effect that promises good potential for clinical application in wound care. Further studies will be required to characterize special molecules encompassing healing properties. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Wound healing and treating wounds: Differential diagnosis and evaluation of chronic wounds.

PubMed

Morton, Laurel M; Phillips, Tania J

2016-04-01

Wounds are an excellent example of how the field of dermatology represents a cross-section of many medical disciplines. For instance, wounds may be caused by trauma, vascular insufficiency, and underlying medical conditions, such as diabetes, hypertension, and rheumatologic and inflammatory disease. This continuing medical education article provides an overview of wound healing and the pathophysiology of chronic wounds and reviews the broad differential diagnosis of chronic wounds. It also describes the initial steps necessary in evaluating a chronic wound and determining its underlying etiology. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

The Effects of Supplemental Zinc and Honey on Wound Healing in Rats

PubMed Central

Sazegar, Ghasem; Seyed Reza, Attarzadeh Hosseini; Behravan, Effat

2011-01-01

Objective(s) Clinicians have long been searching for ways to obtain "super normal" wound healing. Zinc supplementation improves the healing of open wounds. Honey can improve the wound healing with its antibacterial properties. Giving supplemental zinc to normal rats can increase the wound tensile strength. This work is to study the concurrent effects of zinc and honey in wound healing of normal rats. Materials and Methods One hundred and seventy two young rats were randomly divided into four groups: control, zinc-supplement, applied honey, zinc-supplement and applied honey. Two areas of skin about 4 cm² were excised. The wound area was measured every 2 days. After 3 weeks, all animals were killed and tensile strength of wounds, zinc concentration of blood and histological improvement of wounds were evaluated. The results were analyzed using two-way ANOVA and the mean differences were tested. Results It was found that honey could inhibit the bacterial growth in skin excisions. The tensile strength was increased significantly in the second to fourth groups at 21st day (P< 0.001). Also there was a significant increase in tensile strength at the same time in the fourth group. The results of the histological study showed a considerable increase in the collagen fibers, re-epithelialization and re-vascularization in the second to fourth groups. Conclusion The results of the present study indicate that zinc sulfate could retard re-epithelialization, but when used with natural honey (administered topically) it could have influent wound healing in non-zinc-deficient subjects as well. PMID:23493488

Method of making a continuous ceramic fiber composite hot gas filter

DOEpatents

Hill, Charles A.; Wagner, Richard A.; Komoroski, Ronald G.; Gunter, Greg A.; Barringer, Eric A.; Goettler, Richard W.

1999-01-01

A ceramic fiber composite structure particularly suitable for use as a hot gas cleanup ceramic fiber composite filter and method of making same from ceramic composite material has a structure which provides for increased strength and toughness in high temperature environments. The ceramic fiber composite structure or filter is made by a process in which a continuous ceramic fiber is intimately surrounded by discontinuous chopped ceramic fibers during manufacture to produce a ceramic fiber composite preform which is then bonded using various ceramic binders. The ceramic fiber composite preform is then fired to create a bond phase at the fiber contact points. Parameters such as fiber tension, spacing, and the relative proportions of the continuous ceramic fiber and chopped ceramic fibers can be varied as the continuous ceramic fiber and chopped ceramic fiber are simultaneously formed on the porous vacuum mandrel to obtain a desired distribution of the continuous ceramic fiber and the chopped ceramic fiber in the ceramic fiber composite structure or filter.

Process for preparing composite articles from composite fiber blends

NASA Technical Reports Server (NTRS)

McMahon, Paul E. (Inventor); Chung, Tai-Shung (Inventor); Ying, Lincoln (Inventor)

1989-01-01

A composite article is prepared by forming a continuous tow of continuous carbon fibers, forming a continuous tow of thermoplastic polymer fibers, uniformly and continuously spreading the thermoplastic polymer fibers to a selected width, uniformly and continuously spreading the carbon fiber tow to a width that is essentially the same as the selected width for the thermoplastic polymer fiber tow, intermixing the tows intimately, uniformly and continuously, in a relatively tension-free state, continuously withdrawing the intermixed tow and applying the tow to a mold and heating the tow.

Methods of producing continuous boron carbide fibers

DOEpatents

Garnier, John E.; Griffith, George W.

2015-12-01

Methods of producing continuous boron carbide fibers. The method comprises reacting a continuous carbon fiber material and a boron oxide gas within a temperature range of from approximately 1400.degree. C. to approximately 2200.degree. C. Continuous boron carbide fibers, continuous fibers comprising boron carbide, and articles including at least a boron carbide coating are also disclosed.

Painful dressing changes for chronic wounds: assessment and management.

PubMed

Solowiej, Kazia; Upton, Dominic

Wound pain can arise from the wound itself, continuing wound treatment and anticipatory pain, which occurs in some patients as a consequence of negative experiences of care. Specifically, pain caused by the removal and application of dressings has been identified as a major contributor to wound pain, from both patient and health professional perspectives. This article reviews literature on the impact of pain at dressing change, and provides practical suggestions for assessment and management of pain during wound care.

Photobiomodulation with Pulsed and Continuous Wave Near-Infrared Laser (810 nm, Al-Ga-As) Augments Dermal Wound Healing in Immunosuppressed Rats

PubMed Central

Keshri, Gaurav K.; Gupta, Asheesh; Yadav, Anju; Sharma, Sanjeev K.; Singh, Shashi Bala

2016-01-01

Chronic non-healing cutaneous wounds are often vulnerable in one or more repair phases that prevent normal healing and pose challenges to the use of conventional wound care modalities. In immunosuppressed subject, the sequential stages of healing get hampered, which may be the consequences of dysregulated or stagnant wound inflammation. Photobiomodulation (PBM) or low-level laser (light) therapy (LLLT) emerges as a promising drug-free, non-invasive biophysical approach for promoting wound healing, reduction of inflammation, pain and restoration of functions. The present study was therefore undertaken to evaluate the photobiomodulatory effects of 810 nm diode laser (40 mW/cm2; 22.6 J/cm2) with pulsed (10 and 100 Hz, 50% duty cycle) and continuous wave on full-thickness excision-type dermal wound healing in hydrocortisone-induced immunosuppressed rats. Results clearly delineated that 810 nm PBM at 10 Hz was more effective over continuous and 100 Hz frequency in accelerating wound healing by attenuating the pro-inflammatory markers (NF-kB, TNF-α), augmenting wound contraction (α-SM actin), enhancing cellular proliferation, ECM deposition, neovascularization (HIF-1α, VEGF), re-epithelialization along with up-regulated protein expression of FGFR-1, Fibronectin, HSP-90 and TGF-β2 as compared to the non-irradiated controls. Additionally, 810 nm laser irradiation significantly increased CCO activity and cellular ATP contents. Overall, the findings from this study might broaden the current biological mechanism that could be responsible for photobiomodulatory effect mediated through pulsed NIR 810 nm laser (10 Hz) for promoting dermal wound healing in immunosuppressed subjects. PMID:27861614

Fibers comprised of epitaxially grown single-wall carbon nanotubes, and a method for added catalyst and continuous growth at the tip

DOEpatents

Kittrell, W. Carter; Wang, Yuhuang; Kim, Myung Jong; Hauge, Robert H.; Smalley, Richard E.; Marek leg, Irene Morin

2010-06-01

The present invention is directed to fibers of epitaxially grown single-wall carbon nanotubes (SWNTs) and methods of making same. Such methods generally comprise the steps of: (a) providing a spun SWNT fiber; (b) cutting the fiber substantially perpendicular to the fiber axis to yield a cut fiber; (c) etching the cut fiber at its end with a plasma to yield an etched cut fiber; (d) depositing metal catalyst on the etched cut fiber end to form a continuous SWNT fiber precursor; and (e) introducing feedstock gases under SWNT growth conditions to grow the continuous SWNT fiber precursor into a continuous SWNT fiber.

Oxygen and wound care: a review of current therapeutic modalities and future direction.

PubMed

Howard, Michael A; Asmis, Reto; Evans, Karen Kim; Mustoe, Thomas A

2013-01-01

While the importance of oxygen to the wound healing process is well accepted, research and technological advances continue in this field and efforts are ongoing to further utilize oxygen as a therapeutic modality. In this paper, the authors briefly review the role of oxygen in wound healing and discuss the distinct mechanism of action as well as the advantages and disadvantages of the three major oxygen-based therapies currently in clinical use (Hyperbaric Oxygen and Topical Oxygen and Continuous Diffusion of Oxygen), as well as review the existing literature regarding these distinct therapeutic modalities. © 2013 by the Wound Healing Society.

Carbon fiber internal pressure vessels

NASA Technical Reports Server (NTRS)

Simon, R. A.

1973-01-01

Internal pressure vessels were designed; the filament was wound of carbon fibers and epoxy resin and tested to burst. The fibers used were Thornel 400, Thornel 75, and Hercules HTS. Additional vessels with type A fiber were made. Polymeric linears were used, and all burst testing was done at room temperature. The objective was to produce vessels with the highest attainable PbV/W efficiencies. The type A vessels showed the highest average efficiency: 2.56 x 10 to the 6th power cm. Next highest efficiency was with Thornel 400 vessels: 2.21 x 10 to the 6th power cm. These values compare favorably with efficiency values from good quality S-glass vessels, but strains averaged 0.97% or less, which is less than 1/3 the strain of S-glass vessels.

Nonwoven greige cotton for wound healing and hygienic product applications

USDA-ARS?s Scientific Manuscript database

The potential to use greige (non-bleached) cotton in nonwoven absorbent products has received increased attention. This is due to innovations in cotton cleaning and nonwoven hydroentanglement processes that open and expose the hydrophilic cellulosic component of greige cotton fiber to water absorpt...

Traction-assisted Internal Negative Pressure Wound Therapy With Bridging Retention Sutures to Facilitate Staged Closure of High-risk Wounds Under Tension.

PubMed

DeFazio, Michael V; Economides, James M; Anghel, Ersilia L; Mathis, Ryan K; Barbour, John R; Attinger, Christopher E

2017-10-01

Loss of domain often complicates attempts at delayed wound closure in regions of high tension. Wound temporization with traction-assisted internal negative pressure wound therapy (NPWT), using bridging retention sutures, can minimize the effects of edema and elastic recoil that contribute to progressive tissue retraction over time. The investigators evaluated the safety and efficacy of this technique for complex wound closure. Between May 2015 and November 2015, 18 consecutive patients underwent staged reconstruction of complex and/or contaminated soft tissue defects utilizing either conventional NPWT or modified NPWT with instillation and continuous dermatotraction via bridging retention sutures. Instillation of antimicrobial solution was reserved for wounds containing infected/exposed hardware or prosthetic devices. Demographic data, wound characteristics, reconstructive outcomes, and complications were reviewed retrospectively. Eighteen wounds were treated with traction-assisted internal NPWT using the conventional (n = 11) or modified instillation (n = 7) technique. Defects involved the lower extremity (n = 14), trunk (n = 3), and proximal upper extremity (n = 1), with positive cultures identified in 12 wounds (67%). Therapy continued for 3 to 8 days (mean, 4.3 days), resulting in an average wound surface area reduction of 78% (149 cm² vs. 33 cm²) at definitive closure. Seventeen wounds (94%) were closed directly, whereas the remaining defect required coverage with a local muscle flap and skin graft. At final follow-up (mean, 12 months), 89% of wounds remained closed. In 2 patients with delayed, recurrent periprosthetic infection (mean, 7.5 weeks), serial debridement/hardware removal mandated free tissue transfer for composite defect reconstruction. Traction-assisted internal NPWT provides a safe and effective alternative to reduce wound burden and facilitate definitive closure in cases where delayed reconstruction of high-tension wounds is planned.

Visualization of collagen regeneration in mouse dorsal skin using second harmonic generation microscopy

NASA Astrophysics Data System (ADS)

Luo, T.; Chen, J. X.; Zhuo, S. M.; Lu, K. C.; Jiang, X. S.; Liu, Q. G.

2009-03-01

The purpose of this study is to highlight a clearer understanding of the process of collagen regeneration during wound healing. By means of second harmonic generation (SHG) microscopy, the changes of collagen arrangement at the wound margin were analyzed at 0, 3, 5, 7, 11 and 13 days post injury. The degree of collagen disorders associated with the healing process was quantitatively obtained using the aspect ratio of polar plot image of collagen azimuthal angles and the healing status of collagen could be estimated by arithmetical mean deviation ( Ra) of the collagen SHG images. Our results suggest that SHG microscopy has potential advances in the collagen studies during wound healing and the arrangement of collagen fibers gradually transformed from disorder to order so as to contract the wound. It is capable of promoting clinical application of the noninvasive imaging tool and the analysis methods of collagen disorder as an effective scar management for prevention and treatment about aberrant healing.

In situ synthesis of silver-nanoparticles/bacterial cellulose composites for slow-released antimicrobial wound dressing.

PubMed

Wu, Jian; Zheng, Yudong; Song, Wenhui; Luan, Jiabin; Wen, Xiaoxiao; Wu, Zhigu; Chen, Xiaohua; Wang, Qi; Guo, Shaolin

2014-02-15

Bacterial cellulose has attracted increasing attention as a novel wound dressing material, but it has no antimicrobial activity, which is one of critical skin-barrier functions in wound healing. To overcome such deficiency, we developed a novel method to synthesize and impregnate silver nanoparticles on to bacterial cellulose nanofibres (AgNP-BC). Uniform spherical silver nano-particles (10-30 nm) were generated and self-assembled on the surface of BC nano-fibers, forming a stable and evenly distributed Ag nanoparticles coated BC nanofiber. Such hybrid nanostructure prevented Ag nanoparticles from dropping off BC network and thus minimized the toxicity of nanoparticles. Regardless the slow Ag(+) release, AgNP-BC still exhibited significant antibacterial activities with more than 99% reductions in Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, AgNP-BC allowed attachment and growth of epidermal cells with no cytotoxicity emerged. The results demonstrated that AgNP-BC could reduce inflammation and promote wound healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preclinical efficacy and safety of herbal formulation for management of wounds.

PubMed

Ogwang, P E; Nyafuono, J; Agwaya, Moses; Omujal, F; Tumusiime, H R; Kyakulaga, A H

2011-09-01

Medicinal plants in Uganda and other developing countries have been scientifically demonstrated to have medicinal benefits but few or none have been translated to products for clinical use. Most herbal products developed by local herbalists and sold to the public are not standardized and lack efficacy and safety data to support use. To formulate from two Ugandan medicinal plants a herbal product for wound management and test its preclinical safety and efficacy using rat models. Thirty (30) Wistar albino rats were randomly divided into three groups and wounds were surgically created on the mid-dorsal region. The wounds were treated topically with distilled water (group I), Jena(®) (group II)and Neomycin sulfate cream (group III). The effects of the treatments on rate of wound closure, epithelialisation time and histological organization of tissue were assessed. The herbal formulation (Jena) had a significantly higher rate of wound closure than neomycin (p<0.05) which itself was better than distilled water. Epithelialisation time was also significantly shorter for the herbal product (p<0.01). Histological picture revealed more collagen fibers, less inflammation and better tissue remodeling for rats treated with herbal product. The herbal formulation Jena(®) systematically designed and formulated based on two Ugandan medicinal plants is according to this study better than neomycin and probably other imported products for wound management in Uganda. We recommend its trial in a clinical setting as an alternative in wound management.

The Effect of 17β-Estradiol on Cutaneous Wound Healing in Protein-Malnourished Ovariectomized Female Mouse Model

PubMed Central

Mukai, Kanae; Komatsu, Emi; Nakajima, Yukari; Urai, Tamae; Nasruddin; Sugama, Junko; Nakatani, Toshio

2014-01-01

Cutaneous wound healing is delayed by protein malnutrition (PM). On the other hand, estrogen promotes cutaneous wound healing by its anti-inflammatory and cell proliferation effects. Therefore, we hypothesized that estrogen administration in protein-malnourished ovariectomized (OVX) female mice might improve the inflammatory response and promote cutaneous wound healing as well as normal nutrition. To test this hypothesis, we used full-thickness excisional wounds in Control SHAM, PM SHAM, PM OVX and PM OVX+17β-estradiol mice. The Control diet included 200 g/kg protein and the PM diet included 30 g/kg protein. The ratio of wound area in the Control SHAM group was significantly smaller than those in the three PM groups. In addition, microscopic findings also showed that the ratio of collagen fibers, the ratio of myofibroblasts and the number of new blood vessels in the Control SHAM group were significantly greater than those in the three PM groups. However, the number of Ym1-positive cells as an anti-inflammatory M2-like macrophage marker in the PM OVX+17β-estradiol group was significantly higher than those in the other three groups. These results indicate that the appearance of anti-inflammatory M2-like macrophages was promoted by estrogen administration; however, it could not promote cutaneous wound healing upon a low-protein diet. Therefore, it may be confirmed that nutrition is more important for promoting cutaneous wound healing than estrogen administration. PMID:25518000

The effect of 17β-estradiol on cutaneous wound healing in protein-malnourished ovariectomized female mouse model.

PubMed

Mukai, Kanae; Komatsu, Emi; Nakajima, Yukari; Urai, Tamae; Nasruddin; Sugama, Junko; Nakatani, Toshio

2014-01-01

Cutaneous wound healing is delayed by protein malnutrition (PM). On the other hand, estrogen promotes cutaneous wound healing by its anti-inflammatory and cell proliferation effects. Therefore, we hypothesized that estrogen administration in protein-malnourished ovariectomized (OVX) female mice might improve the inflammatory response and promote cutaneous wound healing as well as normal nutrition. To test this hypothesis, we used full-thickness excisional wounds in Control SHAM, PM SHAM, PM OVX and PM OVX+17β-estradiol mice. The Control diet included 200 g/kg protein and the PM diet included 30 g/kg protein. The ratio of wound area in the Control SHAM group was significantly smaller than those in the three PM groups. In addition, microscopic findings also showed that the ratio of collagen fibers, the ratio of myofibroblasts and the number of new blood vessels in the Control SHAM group were significantly greater than those in the three PM groups. However, the number of Ym1-positive cells as an anti-inflammatory M2-like macrophage marker in the PM OVX+17β-estradiol group was significantly higher than those in the other three groups. These results indicate that the appearance of anti-inflammatory M2-like macrophages was promoted by estrogen administration; however, it could not promote cutaneous wound healing upon a low-protein diet. Therefore, it may be confirmed that nutrition is more important for promoting cutaneous wound healing than estrogen administration.

The N-butyl alcohol extract from Hibiscus rosa-sinensis L. flowers enhances healing potential on rat excisional wounds.

PubMed

Shen, Hui-Min; Chen, Chun; Jiang, Ji-Yang; Zheng, Yi-Lin; Cai, Wen-Feng; Wang, Bin; Ling, Zhen; Tang, Liu; Wang, Yuan-Hang; Shi, Gang-Gang

2017-02-23

Hibiscus rosa-sinensis L. (HRS), a folk medicine named Zhujin in China, possess anti-tumor, antioxidant, antibacterial, low density lipoprotein oxidation prevention and macrophage death prevention effects. The leaves and red flowers of HRS have been traditionally used to treat with furuncle and ulceration. To investigate the efficacy and possible mechanism of the N-butyl alcohol extract of HRS (NHRS) red flowers in wound healing by analyzing the collagen fiber deposition, angiogenic activity and macrophages action of the NHRS. In an excisional wound healing model in rats, different concentrations of NHRS, or recombinant bovine basic fibroblast growth factor (rbFGF), were respectively applied twice daily for 9 days. Histopathology was assessed on day 9 via hematoxylin and eosin (HE) and Masson's trichrome (MT) staining, and immunohistochemistry for vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1) and CD68. Immunomodulation by NHRS was evaluated by a carbon clearance test in mice. Wound healing post-surgery was greater in the rbFGF-control, NHRS-M and MHRS-H groups than in the model and 5% dimethylsulfoxide (DMSO)-control groups after the third day. By the sixth day the wound contraction of NHRS-M and MHRS-H groups was much higher than the rbFGF-control group. HE and MT staining revealed that epithelialization, fibroblast distribution, collagen deposition of NHRS-M- and NHRS-H-control groups were significantly higher than the model group. Moreover, immunohistochemistry showed more intense staining of VEGF, TGF-β1 and CD68 in the rbFGF- and NHRS-control groups, compared to that in model and 5% DMSO-control groups. The clearance and phagocytic indices of NHRS-M- and NHRS-H-control groups were significantly higher than that of the carboxyl methyl cellulose (CMC) group in mice. NHRS accelerates wound repair via enhancing the macrophages activity, accelerating angiogenesis and collagen fiber deposition response mediated by VEGF and TGF-β1. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Honey/Chitosan Nanofiber Wound Dressing Enriched with Allium sativum and Cleome droserifolia: Enhanced Antimicrobial and Wound Healing Activity.

PubMed

Sarhan, Wessam A; Azzazy, Hassan M E; El-Sherbiny, Ibrahim M

2016-03-01

Two natural extracts were loaded within fabricated honey, poly(vinyl alcohol), chitosan nanofibers (HPCS) to develop biocompatible antimicrobial nanofibrous wound dressing. The dried aqueous extract of Cleome droserifolia (CE) and Allium sativum aqueous extract (AE) and their combination were loaded within the HPCS nanofibers in the HPCS-CE, HPCS-AE, and HPCS-AE/CE nanofiber mats, respectively. It was observed that the addition of AE resulted in the least fiber diameter (145 nm), whereas the addition of the AE and CE combination resulted in the least swelling ability and the highest weight loss. In vitro antibacterial testing against Staphylococcus aureus, Escherichia coli, Methicillin-resistant S. aureus (MRSA), and multidrug-resistant Pseudomonas aeruginosa was performed in comparison with the commercial dressing AquacelAg and revealed that the HPCS-AE and HPCS-AE/CE nanofiber mats allowed complete inhibition of S. aureus and the HPCS-AE/CE exhibited mild antibacterial activity against MRSA. A preliminary in vivo study revealed that the developed nanofiber mats enhanced the wound healing process as compared to the untreated control as proved by the enhanced wound closure rates in mice and by the histological examination of the wounds. Moreover, comparison with the commercial dressing Aquacel Ag, the HPCS, and HPCS-AE/CE demonstrated similar effects on the wound healing process, whereas the HPCS/AE allowed an enhanced wound closure rate. Cell culture studies proved the biocompatibility of the developed nanofiber mats in comparison with the commercial Aquacel Ag, which exhibited noticeable cytotoxicity. The developed natural nanofiber mats hold potential as promising biocompatible antibacterial wound dressing.

Use of adhesive surgical tape with the absorbable continuous subcuticular suture.

PubMed

Kolt, Jeremy D

2003-08-01

The absorbable continuous subcuticular suture is frequently used to close surgical incisions where the aim is healing by primary intention. A form of adhesive surgical tape is commonly also placed over the wound but this combination closure seems to have its development based on anecdotal, rather than experimental evidence. The present study reviews the scientific literature on the development of sutureless wound closure and presents the current evidence for the use of combination wound closure. Review was undertaken of the medical literature using the PubMed Internet database and cross-referencing major -articles on the subject. The following combinations of key words were searched: skin closure, wound closure, suture technique, sutureless, adhesive tape, op-site, staples, subcuticular suture, complication, infection and scars. Taped closure alone has advantages of lower wound infection rates and greater wound tensile strength, but disadvantages of epidermal reaction, skin edge inversion, doubtful safety and time required for meticulous surgical technique. The use of the continuous absorbable subcuticular suture allows accurate skin edge approximation, which increases the safety margin. The combination closure has a slightly superior cosmetic result to sutureless techniques but no study has been performed to compare the results of combination subcuticular suture and tape, with tape or subcuticular suture alone. There is no evidence in the scientific literature to justify or support the practice of closing a surgical wound with both subcuticular suture and adhesive surgical tape.

Educating Nurses in the United States about Pressure Injuries.

PubMed

Ayello, Elizabeth A; Zulkowski, Karen; Capezuti, Elizabeth; Jicman, Wendy Harris; Sibbald, R Gary

2017-02-01

To provide information about the current state of educating nurses about wound care and pressure injuries with recommendations for the future. This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. After participating in this educational activity, the participant should be better able to:1. Discuss the importance of pressure injury education and wound care for nurses and identify the current state of nursing education on the subject. 2. Identify strategies that can be used to put improved wound care and pressure injury education into practice. Wound care nursing requires knowledge and skill to operationalize clinical guidelines. Recent surveys and studies have revealed gaps in nurses' knowledge of wound care and pressure injuries and their desire for more education, both in their undergraduate programs and throughout their careers. Data from baccalaureate programs in the United States can pinpoint areas for improvement in nursing curriculum content. Lifelong learning about wound care and pressure injuries starts with undergraduate nursing education but continues through the novice-to-expert Benner categories that are facilitated by continuing professional development. This article introduces a pressure injury competency skills checklist and educational strategies based on Adult Learning principles to support knowledge acquisition (in school) and translation (into clinical settings). The responsibility for lifelong learning is part of every nurse's professional practice.

Evaluation of the healing activity of therapeutic clay in rat skin wounds.

PubMed

Dário, Giordana Maciel; da Silva, Geovana Gomes; Gonçalves, Davi Ludvig; Silveira, Paulo; Junior, Adilson Teixeira; Angioletto, Elidio; Bernardin, Adriano Michael

2014-10-01

The use of clays for therapeutic practice is widespread in almost all regions of the world. In this study the physicochemical and microbiological healing characteristics of a clay from Ocara, Brazil, popularly used for therapeutic uses, were analyzed. The presence of Ca, Mg, Al, Fe, and Si was observed, which initially indicated that the clay had potential for therapeutic use. The average particle size of the clay (26.3 μm) can induce the microcirculation of the skin and the XRD analysis shows that the clay is formed by kaolinite and illite, a swelling clay. During the microbiological evaluation there was the need to sterilize the clay for later incorporation into the pharmaceutical formula. The accelerated stability test at 50°C for 3 months has showed that the pharmaceutical formula remained stable with a shelf life of two years. After the stability test the wound-healing capacity of the formulation in rats was evaluated. It was observed that the treatment made with the formulation containing the Ocara clay showed the best results since the formula allowed greater formation of collagen fibers and consequent regeneration of the deep dermis after seven days of treatment and reepithelialization and continuous formation of granulation tissue at the 14th day. Copyright © 2014 Elsevier B.V. All rights reserved.

Nanomaterials for Functional Textiles and Fibers

NASA Astrophysics Data System (ADS)

Rivero, Pedro J.; Urrutia, Aitor; Goicoechea, Javier; Arregui, Francisco J.

2015-12-01

Nanoparticles are very interesting because of their surface properties, different from bulk materials. Such properties make possible to endow ordinary products with new functionalities. Their relatively low cost with respect to other nano-additives make them a promising choice for industrial mass-production systems. Nanoparticles of different kind of materials such as silver, titania, and zinc oxide have been used in the functionalization of fibers and fabrics achieving significantly improved products with new macroscopic properties. This article reviews the most relevant approaches for incorporating such nanoparticles into synthetic fibers used traditionally in the textile industry allowing to give a solution to traditional problems for textiles such as the microorganism growth onto fibers, flammability, robustness against ultraviolet radiation, and many others. In addition, the incorporation of such nanoparticles into special ultrathin fibers is also analyzed. In this field, electrospinning is a very promising technique that allows the fabrication of ultrathin fiber mats with an extraordinary control of their structure and properties, being an ideal alternative for applications such as wound healing or even functional membranes.

Nanomaterials for Functional Textiles and Fibers.

PubMed

Rivero, Pedro J; Urrutia, Aitor; Goicoechea, Javier; Arregui, Francisco J

2015-12-01

Nanoparticles are very interesting because of their surface properties, different from bulk materials. Such properties make possible to endow ordinary products with new functionalities. Their relatively low cost with respect to other nano-additives make them a promising choice for industrial mass-production systems. Nanoparticles of different kind of materials such as silver, titania, and zinc oxide have been used in the functionalization of fibers and fabrics achieving significantly improved products with new macroscopic properties. This article reviews the most relevant approaches for incorporating such nanoparticles into synthetic fibers used traditionally in the textile industry allowing to give a solution to traditional problems for textiles such as the microorganism growth onto fibers, flammability, robustness against ultraviolet radiation, and many others. In addition, the incorporation of such nanoparticles into special ultrathin fibers is also analyzed. In this field, electrospinning is a very promising technique that allows the fabrication of ultrathin fiber mats with an extraordinary control of their structure and properties, being an ideal alternative for applications such as wound healing or even functional membranes.

Process for preparing tows from composite fiber blends

NASA Technical Reports Server (NTRS)

McMahon, Paul (Inventor); Chung, Tai-Shung (Inventor); Ying, Lincoln (Inventor)

1989-01-01

A continuous, substantially uniform tow useful in forming composite molded articles is prepared by forming a continuous tow of continuous carbon fibers, forming a continuous tow of thermoplastic polymer fibers to a selected width, uniformly and continuously spreading the carbon fiber two to a width that is essentially the same as the selected width for the thermoplastic polymer fiber tow, intermixing the tows intimately, uniformly and continuously, in a relatively tension-free state, and continuosuly withdrawing the intermixed tow.

Effects on diameter and morphology of polycaprolactone nanofibers infused with various concentrations of selenium nanoparticles

NASA Astrophysics Data System (ADS)

Kamaruzaman, Nurul Asyikin; Yusoff, Abdull Rahim Mohd; Buang, Nor Aziah; Salleh, Nik Ghazali Nik

2017-12-01

Electrospinning is one of the techniques used in the fabrication of nanofibers. Polycaprolactone (PCL), is a biodegradable polymer which was commonly electrospun without the presence of nanoparticles as additives and/or filler in the applications such as tissue engineering, biosensors, filtration, wound dressings, drug delivery and enzyme immobilization. In this study, via FESEM analyses, the effects on the diameter and morphology of PCL nanofibers was investigated with respect to various concentration of selenium nanoparticles (SeNP). Increasing the concentration of SeNP from 0.2 to 1.0% (w/v) resulted in increased of fiber diameter as well as the density of the nanofiber networking. Consequently, the formation of beads have also increased with the increment of the concentration of SeNP. The images from FESEM micrographs showed the formation of "aligned fibers" with the average size of less than 550 nm. The optimized concentration of SeNP obtained was 0.4 % w/v for the formation of aligned fibers with a uniform diameter in size and the least formation of beads in the matrices. Aligned nanofibers are biocompatible and can be used in tissue engineering and wound dressing applications. Meanwhile, nanofibers with beads are suitable for filtration design in water and gaseous applications.

[Treatment of infected diabetic foot ulcers clinical effectiveness of a dressing of alginate and hydrocolloid, with silver fiber. Analysis of results of a series of cases].

PubMed

Lázaro-Martínez, J L; Cecilia-Matilla, A; Aragón-Sánchez, J; García-Morales, E; Garcia-Alvarez, Y; Alvaro-Afonso, F

2013-11-01

High levels of bacterial load have shown a deleterious influence on wound healing. Using antimicrobial dressings can control ulcers' bioburden. The aim of our study was to evaluate the improving of infected diabetic foot ulcers due an alginate's fiber and hydrocolloid silver dressing. We analysed a case series of 6 patients with diabetic foot ulcers without peripheral vascular disease and diagnosed from critical colonization and/or local infection according the presence of inflammation clinical signs. Patients were treated for a minimum period of two weeks. We analysed the percentage reduction in ulcer area from the day of enrolment to antimicrobial dressing removal. The duration of treatment had a median of 5 weeks with a minimum of 2 weeks and up to 6. The median percentage of area reduction of the wounds was 47.7% (range: 0.5%-90%). The mean percentage reduction on the lesion was 58% from 2 weeks and 67.14% at 3 weeks. All patients had reduced significantly their size at 3 weeks from beginning of treatment (p < 0.05). The use of an alginate's fiber and hydrocolloid silver dressing promotes healing on diabetic foot ulcers with local infection, reducing the inflammatory clinical signs significantly over a period of three weeks.

Wound management in patients with advanced illness.

PubMed

Maida, Vincent

2013-03-01

To emphasize that the management of wounds represents a significant component within the overall supportive and palliative care of patients with advanced illness. It is also intended to clarify the linguistics that are commonly used around patients with wounds. New paradigms for wound management, wound outcomes, and goal setting have been defined and graphically depicted. Recent studies show that wounds may be used as prognostic factors for patients with advanced illness. Data from recent studies also demonstrate that marginal levels of wound healing are possible for all wound classes affecting patients with advanced illness. When indicated, time-limited trials of wound healing strategies should be facilitated by the Wound Bed Preparation Paradigm. Wound palliation may be guided through the use of the Toronto Symptom Assessment System for Wounds (TSAS-W). Wound management must continue to evolve as a tenet within the overall supportive and palliative care of patients with advanced illness.

zWEDGI: Wounding and Entrapment Device for Imaging Live Zebrafish Larvae

PubMed Central

Huemer, Kayla; Squirrell, Jayne M.; Swader, Robert; LeBert, Danny C.; Huttenlocher, Anna; Eliceiri, Kevin W.

2017-01-01

Abstract Zebrafish, an established model organism in developmental biology, is also a valuable tool for imaging wound healing in space and time with cellular resolution. However, long-term imaging of wound healing poses technical challenges as wound healing occurs over multiple temporal scales. The traditional strategy of larval encapsulation in agarose successfully limits sample movement but impedes larval development and tissue regrowth and is therefore not amenable to long-term imaging of wound healing. To overcome this challenge, we engineered a functionally compartmentalized device, the zebrafish Wounding and Entrapment Device for Growth and Imaging (zWEDGI), to orient larvae for high-resolution microscopy, including confocal and second harmonic generation (SHG), while allowing unrestrained tail development and regrowth. In this device, larval viability was maintained and tail regrowth was improved over embedding in agarose. The quality of tail fiber SHG images collected from larvae in the device was similar to fixed samples but provided the benefit of time lapse data collection. Furthermore, we show that this device was amenable to long-term (>24 h) confocal microscopy of the caudal fin. Finally, the zWEDGI was designed and fabricated using readily available techniques so that it can be easily modified for diverse experimental imaging protocols. PMID:27676647

Software Computes Tape-Casting Parameters

NASA Technical Reports Server (NTRS)

deGroh, Henry C., III

2003-01-01

Tcast2 is a FORTRAN computer program that accelerates the setup of a process in which a slurry containing metal particles and a polymeric binder is cast, to a thickness regulated by a doctor blade, onto fibers wound on a rotating drum to make a green precursor of a metal-matrix/fiber composite tape. Before Tcast2, setup parameters were determined by trial and error in time-consuming multiple iterations of the process. In Tcast2, the fiber architecture in the final composite is expressed in terms of the lateral distance between fibers and the thickness-wise distance between fibers in adjacent plies. The lateral distance is controlled via the manner of winding. The interply spacing is controlled via the characteristics of the slurry and the doctor-blade height. When a new combination of fibers and slurry is first cast and dried to a green tape, the shrinkage from the wet to the green condition and a few other key parameters of the green tape are measured. These parameters are provided as input to Tcast2, which uses them to compute the doctor-blade height and fiber spacings needed to obtain the desired fiber architecture and fiber volume fraction in the final composite.

A phytomodulatory hydrogel with enhanced healing effects.

PubMed

Vasconcelos, Mirele S; Souza, Tamiris F G; Figueiredo, Ingrid S; Sousa, Emília T; Sousa, Felipe D; Moreira, Renato A; Alencar, Nylane M N; Lima-Filho, José V; Ramos, Márcio V

2018-04-01

The healing performance of a hydrogel composed of hemicelluloses extracted from seeds of Caesalpinia pulcherrima (Fabaceae) and mixed with phytomodulatory proteins obtained from the latex of Calotropis procera was characterized on excisional wounds. The hydrogel did not induce dermal irritability. When topically used on excisional wounds, the hydrogel enhanced healing by wound contraction. Histology and the measurement of inflammatory mediators (myeloperoxidase, interleukin-1β, and interleukin-6) suggested that the inflammatory phase of the healing process was intensified, stimulating fibroplasia and neovascularization (proliferative phase) and tissue remodeling by increasing new collagen fiber deposition. In addition, reduction on levels of malondialdehyde in the groups that the hydrogel was applied suggested that the oxidative stress was reduced. The hydrogel performed better than the reference drug used, as revealed by the extended thickness of the remodeled epithelium. Copyright © 2018 John Wiley & Sons, Ltd.

Method of fabricating graphite for use as a skeletal prosthesis and product thereof

DOEpatents

Eatherly, Walter P.; Robbins, J. M.; Rosson, Sr., David E.

1978-01-01

A method for producing porous graphite for use as bone replacement with a structure for osteon penetration. Graphite is produced with ordered circular pores of 100 to 1000 microns in diameter covering at least 25% of the exposed surfaces. A cylindrical fiber is coated with a carbon flour-pitch mix and is then wound on a bobbin in a predetermined manner. The product of winding is dried, pressed, carbonized, and then graphitized. The fibers are removed either chemically or by volatilization during carbonization or graphitization.

Systematic review and meta-analysis of continuous local anaesthetic wound infiltration versus epidural analgesia for postoperative pain following abdominal surgery.

PubMed

Ventham, N T; Hughes, M; O'Neill, S; Johns, N; Brady, R R; Wigmore, S J

2013-09-01

Local anaesthetic wound infiltration techniques reduce opiate requirements and pain scores. Wound catheters have been introduced to increase the duration of action of local anaesthetic by continuous infusion. The aim was to compare these infiltration techniques with the current standard of epidural analgesia. A meta-analysis of randomized clinical trials (RCTs) evaluating wound infiltration versus epidural analgesia in abdominal surgery was performed. The primary outcome was pain score at rest after 24 h on a numerical rating scale. Secondary outcomes were pain scores at rest at 48 h, and on movement at 24 and 48 h, with subgroup analysis according to incision type and administration regimen(continuous versus bolus), opiate requirements, nausea and vomiting, urinary retention, catheter-related complications and treatment failure. Nine RCTs with a total of 505 patients were included. No differences in pain scores at rest 24 h after surgery were detected between epidural and wound infiltration. There were no significant differences in pain score at rest after 48 h, or on movement at 24 or 48 h after surgery. Epidural analgesia demonstrated a non-significant a trend towards reduced pain scores on movement and reduced opiate requirements. There was a reduced incidence of urinary retention in the wound catheter group. Within a heterogeneous group of RCTs, use of local anaesthetic wound infiltration was associated with pain scores comparable to those obtained with epidural analgesia. Further procedure-specific RCTs including broader measures of recovery are recommended to compare the overall efficacy of epidural and wound infiltration analgesic techniques.

Novel application of vacuum sealing drainage with continuous irrigation of potassium permanganate for managing infective wounds of gas gangrene.

PubMed

Hu, Ning; Wu, Xing-Huo; Liu, Rong; Yang, Shu-Hua; Huang, Wei; Jiang, Dian-Ming; Wu, Qiang; Xia, Tian; Shao, Zeng-Wu; Ye, Zhe-Wei

2015-08-01

Traumatic gas gangrene is a fatal infection mainly caused by Clostridium perfringens. It is a challenge to manage gas gangrene in open wounds and control infection after debridement or amputation. The aim of the present study was to use vacuum sealing drainage (VSD) with continuous irrigation of potassium permanganate to manage infective wounds of gas gangrene and observe its clinical efficacy. A total of 48 patients with open traumatic gas gangrene infection were included in this study. Amputations were done for 27 patients, and limb salvage procedures were performed for the others. After amputation or aggressive debridement, the VSD system, including polyvinyl alcohol (PVA) foam dressing and polyurethane (PU) film, with continuous irrigation of 1:5000 potassium permanganate solutions, was applied to the wounds. During the follow-up, all the patients healed without recurrence within 8-18 months. There were four complications. Cardiac arrest during amputation surgery occurred in one patient who suffered from severe septic shock. Emergent resuscitation was performed and the patient returned to stable condition. One patient suffered from mixed infection of Staphylococcal aureus, and a second-stage debridement was performed. One patient suffered from severe pain of the limb after the debridement. Exploratory operation was done and the possible reason was trauma of a local peripheral nerve. Three cases of crush syndrome had dialysis treatment for concomitant renal failure. In conclusion, VSD can convert open wound to closed wound, and evacuate necrotic tissues. Furthermore, potassium permanganate solutions help eliminate anaerobic microenvironment and achieve good therapeutic effect on gas gangrene and mixed infection. VSD with continuous irrigation of potassium permanganate is a novel, simple and feasible alternative for severe traumatic open wounds with gas gangrene infection.

Mechanical Unloading Impairs Keratinocyte Migration and Angiogenesis During Cutaneous Wound Healing

DTIC Science & Technology

2008-02-01

Research, Fort Sam Houston, Texas; and 4Center for Wound Healing and Tissue Regeneration, College of Dentistry , University of Illinois at Chicago... generation of degradative enzymes, additional matrix proteins, and cross- linking of collagen, processes which can continue for years to months following the...tissue repair during normal physiological wound healing (5). In an uncompromised individual, the wound healing process generally proceeds with- out

Effects of aroeira (Schinus terebinthifoliu Raddi) oil on cutaneous wound healing in rats.

PubMed

Estevão, Lígia Reis Moura; Mendonça, Fábio de Souza; Baratella-Evêncio, Liriane; Simões, Ricardo Santos; Barros, Maria Edna Gomes de; Arantes, Rosa Maria Esteves; Rachid, Milene Alvarenga; Evêncio-Neto, Joaquim

2013-03-01

To evaluate the effects of aroeira (Schinus terebinthifolius) ointment on skin wound healing in rats. Adult male rats (n=20) were divided into four groups of five animals each, as follows: G4, G7, G14 and G21, which corresponds to 4th, 7th, 14th and 21th days postoperatively. Each animal were made two incisions on the skin, including the subcutaneous tissue, in the right and left sides of thoracic region, separated by a distance of two inches. The right lesion was treated with base ointment (vaseline, lanolin); the left one was treated with base ointment containing 5% of aroeira oil. At the end of each experimental period the lesions were evaluated for the contraction degree. Then held the collection of fragments that were fixed in 10% formalin and processed for paraffin embedding. In the histological sections (5μm) was evaluated the morphology and quantified the collagen and blood vessels. The data obtained were submitted to ANOVA test complemented by Tukey-Kramer test (p<0.05). The contraction of the lesions was higher in wounds treated with aroeira oil than in controls at 7th and 14th days (p<0.01), whereas in the 21st day all lesions were already completely healed. The morphology showed granulation tissue more developed, with fibroblasts more bulky and collagen fibers more arranged in the experimental group at 4th, 7th and 14th days. The morphometry showed a significant increase in the quantification of collagen fibers in the experimental group at 7th and 14th days (p<0.05). The aroeira oil accelerates the healing process of wounds as a macroscopic, morphological and morphometrical analysis.

Debridement: controlling the necrotic/cellular burden.

PubMed

Ayello, Elizabeth A; Cuddigan, Janet E

2004-03-01

To provide physicians and nurses with an overview of the options for debriding a chronic wound to improve wound healing. This continuing education activity is intended for physicians and nurses with an interest in learning about methods for debriding chronic wounds to promote wound healing. After reading the article and taking the test, the participant will be able to: 1. Describe the 4 types of debridement most commonly used in clinical practice. 2. Describe when to debride a wound and how to determine which method to use.

Cotton Study: Albumin Binding and its Effect on Elastase Activity in the Chronic Non-healing Wound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castro, Nathan J.; Goheen, Steven C.

A comparative examination of two methods, the classical- and chromatographic, commonly used to study adsorption isotherms is presented. Both methods were used to study the solid/liquid interface of two different derivatives of cotton fiber and bovine serum albumin (BSA).

Carbon Fiber Composites for Cryogenic Filament-Wound Vessels.

DTIC Science & Technology

in terms of cryogenic strength properties in epoxy composites. Of the resin systems tested in NOL Ring composites, CTBN /ERLB 4617 exhibited the...bidirectional composite bars showed that the Epon 828/Empol 1040 resin was better at all test temperatures, with the CTBN /ERLB 4617 composites giving somewhat

In vitro hemostatic, hydrogen peroxide production and elastase sequestration properties of nonwoven ultra clean greige cotton dressing

USDA-ARS?s Scientific Manuscript database

Nonwoven UltraCleanTM Cotton (highly cleaned and hydroentangled, greige cotton) retains the native wax and pectin content (~2%) of the cotton fiber traditionally removed from scoured and bleached cotton gauze, yet potentially affording wound healing properties. In vitro thromboelastography, hydrog...

Current management of wound healing.

PubMed

Gottrup, F; Karlsmark, T

2009-06-01

While the understanding of wound pathophysiology has progressed considerably over the past decades the improvements in clinical treatment has occurred to a minor degree. During the last years, however, new trends and initiatives have been launched, and we will continue to attain new information in the next decade. It is the hope that increasing parts of the new knowledge from basic wound healing research will be implemented in daily clinical practice. The development of new treatment products will also continue, and especially new technologies with combined types of dressing materials or dressing containing active substances will be accentuated. Further developments in the management structure and education will also continue and consensus of treatment guidelines, recommendations and organization models will hopefully be achieved.

Methods for producing silicon carbide fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garnier, John E.; Griffith, George W.

Methods of producing silicon carbide fibers. The method comprises reacting a continuous carbon fiber material and a silicon-containing gas in a reaction chamber at a temperature ranging from approximately 1500.degree. C. to approximately 2000.degree. C. A partial pressure of oxygen in the reaction chamber is maintained at less than approximately 1.01.times.10.sup.2 Pascal to produce continuous alpha silicon carbide fibers. Continuous alpha silicon carbide fibers and articles formed from the continuous alpha silicon carbide fibers are also disclosed.

Silicon carbide fibers and articles including same

DOEpatents

Garnier, John E; Griffith, George W

2015-01-27

Methods of producing silicon carbide fibers. The method comprises reacting a continuous carbon fiber material and a silicon-containing gas in a reaction chamber at a temperature ranging from approximately 1500.degree. C. to approximately 2000.degree. C. A partial pressure of oxygen in the reaction chamber is maintained at less than approximately 1.01.times.10.sup.2 Pascal to produce continuous alpha silicon carbide fibers. Continuous alpha silicon carbide fibers and articles formed from the continuous alpha silicon carbide fibers are also disclosed.

Platelet-rich plasma: a biomimetic approach to enhancement of surgical wound healing.

PubMed

Fernandez-Moure, Joseph S; Van Eps, Jeffrey L; Cabrera, Fernando J; Barbosa, Zonia; Medrano Del Rosal, Guillermo; Weiner, Bradley K; Ellsworth, Warren A; Tasciotti, Ennio

2017-01-01

Platelets are small anucleate cytoplasmic cell bodies released by megakaryocytes in response to various physiologic triggers. Traditionally thought to be solely involved in the mechanisms of hemostasis, platelets have gained much attention due to their involvement wound healing, immunomodulation, and antiseptic properties. As the field of surgery continues to evolve so does the need for therapies to aid in treating the increasingly complex patients seen. With over 14 million obstetric, musculoskeletal, and urological and gastrointestinal surgeries performed annually, the healing of surgical wounds continues to be of upmost importance to the surgeon and patient. Platelet-rich plasma, or platelet concentrate, has emerged as a possible adjuvant therapy to aid in the healing of surgical wounds and injuries. In this review, we will discuss the wound healing properties of platelet-rich plasma and various surgical applications. Copyright © 2016 Elsevier Inc. All rights reserved.

Overview of Wound Healing and Management.

PubMed

Childs, Dylan R; Murthy, Ananth S

2017-02-01

Wound healing is a highly complex chain of events, and although it may never be possible to eliminate the risk of experiencing a wound, clinicians' armamentarium continues to expand with methods to manage it. The phases of wound healing are the inflammatory phase, the proliferative phase, and the maturation phase. The pathway of healing is determined by characteristics of the wound on initial presentation, and it is vital to select the appropriate method to treat the wound based on its ability to avoid hypoxia, infection, excessive edema, and foreign bodies. Copyright © 2016 Elsevier Inc. All rights reserved.

Oxynitride glass fibers

NASA Technical Reports Server (NTRS)

Patel, Parimal J.; Messier, Donald R.; Rich, R. E.

1991-01-01

Research at the Army Materials Technology Laboratory (AMTL) and elsewhere has shown that many glass properties including elastic modulus, hardness, and corrosion resistance are improved markedly by the substitution of nitrogen for oxygen in the glass structure. Oxynitride glasses, therefore, offer exciting opportunities for making high modulus, high strength fibers. Processes for making oxynitride glasses and fibers of glass compositions similar to commercial oxide glasses, but with considerable enhanced properties, are discussed. We have made glasses with elastic moduli as high as 140 GPa and fibers with moduli of 120 GPa and tensile strengths up to 2900 MPa. AMTL holds a U.S. patent on oxynitride glass fibers, and this presentation discusses a unique process for drawing small diameter oxynitride glass fibers at high drawing rates. Fibers are drawn through a nozzle from molten glass in a molybdenum crucible at 1550 C. The crucible is situated in a furnace chamber in flowing nitrogen, and the fiber is wound in air outside of the chamber, making the process straightforward and commercially feasible. Strengths were considerably improved by improving glass quality to minimize internal defects. Though the fiber strengths were comparable with oxide fibers, work is currently in progress to further improve the elastic modulus and strength of fibers. The high elastic modulus of oxynitride glasses indicate their potential for making fibers with tensile strengths surpassing any oxide glass fibers, and we hope to realize that potential in the near future.

21 CFR 878.4018 - Hydrophilic wound dressing.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hydrophilic wound dressing. 878.4018 Section 878.4018 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4018 Hydrophilic wound dressing...

21 CFR 878.4018 - Hydrophilic wound dressing.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hydrophilic wound dressing. 878.4018 Section 878.4018 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4018 Hydrophilic wound dressing...

21 CFR 878.4020 - Occlusive wound dressing.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing...

21 CFR 878.4020 - Occlusive wound dressing.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing...

21 CFR 878.4018 - Hydrophilic wound dressing.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hydrophilic wound dressing. 878.4018 Section 878.4018 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4018 Hydrophilic wound dressing...

21 CFR 878.4020 - Occlusive wound dressing.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Occlusive wound dressing. 878.4020 Section 878.4020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4020 Occlusive wound dressing...

Local anesthetics differentially inhibit sympathetic neuron-mediated and C fiber-mediated synovial neurogenic plasma extravasation.

PubMed

Pietruck, Christian; Grond, Stefan; Xie, Guo-Xi; Palmer, Pamela P

2003-05-01

Local anesthetics are used for local irrigation after many types of operations. However, recent evidence of toxic effects of local anesthetics at large concentrations during continuous administration suggests an advantage of using decreased local anesthetic concentrations for irrigation solutions. In this study, we determined whether smaller concentrations of local anesthetics may maintain an antiinflammatory and, therefore, analgesic effect without the risk of possible toxicity. Lidocaine and bupivacaine were studied for their ability to inhibit both components of neurogenic inflammation-C fiber-mediated and sympathetic postganglionic neuron (SPGN)-mediated inflammation-in the rat knee joint. Intraarticular lidocaine 0.02% reduced 5-hydroxytryptamine (5-HT)-induced (SPGN-mediated) plasma extravasation (PE) by 35%, and further decreases were obtained by perfusing larger concentrations of lidocaine. Intraarticular bupivacaine 0.025% inhibited 5-HT-induced PE by 60%, and a 95% inhibition was obtained with bupivacaine 0.05%. Larger local anesthetic concentrations were necessary to inhibit C fiber-mediated PE than those required to inhibit SPGN-mediated PE. Lidocaine 0.4% was required to reduce mustard oil-induced PE by 60%. Lidocaine 2% inhibited mustard oil-induced PE to baseline levels. Bupivacaine 0.1% was required for an 80% reduction of PE. Bupivacaine 0.25% inhibited mustard oil-induced PE to baseline levels. Our results demonstrate differential effects of local anesthetics on SPGN- and C fiber-mediated PE but confirm the concept of using smaller concentrations of local anesthetics to achieve inhibition of postoperative inflammation. Local anesthetic wound irrigation is often used to treat postoperative surgical pain. Large concentrations of local anesthetics are usually used, and these concentrations may have possible neurotoxic and myotoxic effects. Our results demonstrate antiinflammatory effects of lidocaine and bupivacaine at concentrations smaller than used clinically.

Effect of Malva sylvestris cream on burn injury and wounds in rats

PubMed Central

Nasiri, Ebrahim; Hosseinimehr, Seyed Jalal; Azadbakht, Mohammad; Akbari, Jafar; Enayati-fard, Reza; Azizi, Sohail

2015-01-01

Objectives: Burn injury is one of the most health-threatening problems in the world. Malva sylvestris (M. sylvestris) flowers have a high mucilage content and are used as a remedy for cut wound and dermal infected wounds in Iranian folklore Medicine. The purpose of this study was to investigate the effect of M. sylvestris cream on the second degree burn injury in rats. Materials and Methods: Five groups of 10 rats per group were burned with hot metal plate. Animals were administrated divided as control, normal saline, standard silver sulfadiazine 1% (SSD), 5% M. sylvestris, and 10% M. sylvestris into separate groups. Wound area, percentage of wound contraction, and histological and bacteriological assessments were evaluated. Results: Wound sizes were not significantly different among groups on 1st and 3rd days after burn injury, while they were significantly different among groups after 7th day post-burn injury. The average areas of wounds on the 15th day were 7.5±2.9, 6.7±2, 10.5±1.6, 4.7±2, and 4.5±2 cm2 for base cream, normal saline, SSD, 5% M. sylvestris, and 10% M. sylvestris, respectively. The results of histology exhibited well-formed horizontally-oriented collagen fibers in MS topical treatment groups. Microorganisms existed in the SSD group were most probably Staphilococcus epidermitis and for NS group were staphylococcus saprophiteccus. Conclusion: M. sylvestris cream improved histological changes of tissue components in the process of healing when compared with SSD cream. Therefore, it can be used as a topical treatment agent for burn wound. PMID:26909337

The Healing Effect of Arnebia Euchroma Ointment versus Silver Sulfadiazine on Burn Wounds in Rat

PubMed Central

Nasiri, Ebrahim; Hosseinimehr, Seyed Jalal; Azadbakht, Mohammad; Akbari, Jafar; Enayati-Fard, Reza; Azizi, Sohail; Azadbakht, Masoud

2015-01-01

BACKGROUND Burn is still a majordevastating condition in emergency medicine departments among both genders and all age groups in all developed and developing countries, leading to physical, psychological scars and economical burden. The present study aimed to determine the healing effect of topical treatment with Arnebia euchroma on second-degree burn wound in rats. METHODS Fifty rats were divided into 4 equal groups receiving the ointment base, normal saline (NS), standard 1% silver sulfadiazine (SSD), and 5% and 10% Arnebia euchroma ointments (AEO). The mean of burn area, percentage of wound contraction, histopathological and bacteriological assessments in the injured area were dtermined during the study. RESULTS Average area of wound on the 10th day was 10.2±2.3, 8.4±2.6, 12.4±2.5, 5.9±2.2 and 5.7±2 cm2 for ointment base, NS, 1% SSD, and 5% and 10% AEO, respectively. Wound size was significantly lower in 10% AEO than 1% SSD and control groups on the 10th day post-burn injury. On day 11, the percentage of wound contraction in 5% and 10% AEO was 53.9%±14.7% and 55.9±10.5% which was more than 1% SSD (15.3±10.8%). The collagen fibers were well formed and horizontally-oriented in 5% and 10% AEO groups when compared with other groups. CONCLUSION Arnebia euchroma ointment was an effective treatment for healing of burn wounds in comparison with SSD and can be regarded as an alternative topical treatment for burn wounds. PMID:26284182

Combined effect of substance P and curcumin on cutaneous wound healing in diabetic rats.

PubMed

Kant, Vinay; Kumar, Dinesh; Prasad, Raju; Gopal, Anu; Pathak, Nitya N; Kumar, Pawan; Tandan, Surender K

2017-05-15

Our earlier studies demonstrated that topically applied substance P (SP) or curcumin on excision skin wound accelerated the wound healing in streptozotocin-induced diabetic rats. In the present study, we aimed to evaluate the wound healing potential of combination of SP and curcumin in diabetic rats. Open cutaneous excision wound was created on the back of each of the 60 diabetic rats. Wound-inflicted rats were equally divided into three groups namely, control, gel treated, and SP + curcumin treated. Normal saline, pluronic gel, and SP (0.5 × 10 -6 M) + curcumin (0.15%) were topically applied once daily for 19 d to these control, gel-treated, and SP + curcumin groups, respectively. SP + curcumin combination significantly accelerated wound closure and decreased messenger RNA expressions of tumor necrosis factor-alpha, interleukin-1beta, and matrix metalloproteinase-9, whereas the combination markedly increased the expressions of interleukin-10, vascular endothelial growth factor, transforming growth factor-beta1, hypoxia-inducible factor 1-alpha, stromal cell-derived factors-1alpha, heme oxygenase-1 and endothelial nitric oxide synthase, and activities of superoxide dismutase, catalase, and glutathione peroxidase in granulation-healing tissue, compared with control and gel-treated groups. In combination group, granulation tissue was better, as was evidenced by improved fibroblast proliferation, collagen deposition, microvessel density, growth-associated protein 43-positive nerve fibers, and thick regenerated epithelial layer. The combination of SP and curcumin accelerated wound healing in diabetic rats and both the drugs were compatible at the doses used in this study. Copyright © 2017 Elsevier Inc. All rights reserved.

Exosomes derived from human amniotic epithelial cells accelerate wound healing and inhibit scar formation.

PubMed

Zhao, Bin; Zhang, Yijie; Han, Shichao; Zhang, Wei; Zhou, Qin; Guan, Hao; Liu, Jiaqi; Shi, Jihong; Su, Linlin; Hu, Dahai

2017-04-01

Wound healing is a highly orchestrated physiological process consisting of a complex events, and scarless wound healing is highly desired for the development and application in clinical medicine. Recently, we have demonstrated that human amniotic epithelial cells (hAECs) promoted wound healing and inhibited scar formation through a paracrine mechanism. However, exosomes (Exo) are one of the most important paracrine factors. Whether exosomes derived from human amniotic epithelial cells (hAECs-Exo) have positive effects on scarless wound healing have not been reported yet. In this study, we examined the role of hAECs-Exo on wound healing in a rat model. We found that hAECs, which exhibit characteristics of both embryonic and mesenchymal stem cells, have the potential to differentiate into all three germ layers. hAECs-Exo ranged from 50 to 150 nm in diameter, and positive for exosomal markers CD9, CD63, CD81, Alix, TSG101 and HLA-G. Internalization of hAECs-Exo promoted the migration and proliferation of fibroblasts. Moreover, the deposition of extracellular matrix (ECM) were partly abolished by the treatment of high concentration of hAECs-Exo (100 μg/mL), which may be through stimulating the expression of matrix metalloproteinase-1 (MMP-1). In vivo animal experiments showed that hAECs-Exo improved the skin wound healing with well-organized collagen fibers. Taken together, These findings represent that hAECs-Exo can be used as a novel hope in cell-free therapy for scarless wound healing.

Nanocellulose in spun continuous fibers: A review and future outlook

Treesearch

Craig Clemons

2016-01-01

Continuous fibers are commonly manufactured for a wide variety of uses such as filters, textiles, and composites. For example, most fibrous reinforcements (e.g., carbon fiber, glass fiber) for advanced composites are continuous fibers or yarns, fabrics, and preforms made from them. This allows broad flexibility in design and manufacturing approaches by controlling...

Antioxidative study of Cerium Oxide nanoparticle functionalised PCL-Gelatin electrospun fibers for wound healing application.

PubMed

Rather, Hilal Ahmad; Thakore, Ria; Singh, Ragini; Jhala, Dhwani; Singh, Sanjay; Vasita, Rajesh

2018-06-01

Skin wound healing involves a coordinated cellular response to achieve complete reepithelialisation. Elevated levels of reactive oxygen species (ROS) in the wound environment often pose a hindrance in wound healing resulting in impaired wound healing process. Cerium oxide nanoparticles (CeNPs) have the ability to protect the cells from oxidative damage by actively scavenging the ROS. Furthermore, matrices like nanofibers have also been explored for enhancing wound healing. In the current study CeNP functionalised polycaprolactone (PCL)-gelatin nanofiber (PGNPNF) mesh was fabricated by electrospinning and evaluated for its antioxidative potential. Wide angle XRD analysis of randomly oriented nanofibers revealed ∼2.6 times reduced crystallinity than pristine PCL which aided in rapid degradation of nanofibers and release of CeNP. However, bioactive composite made between nanoparticles and PCL-gelatin maintained the fibrous morphology of PGNPNF upto 14 days. The PGNPNF mesh exhibited a superoxide dismutase (SOD) mimetic activity due to the incorporated CeNPs. The PGNPNF mesh enhanced proliferation of 3T3-L1 cells by ∼48% as confirmed by alamar blue assay and SEM micrographs of cells grown on the nanofibrous mesh. Furthermore, the PGNPNF mesh scavenged ROS, which was measured by relative DCF intensity and fluorescence microscopy; and subsequently increased the viability and proliferation of cells by three folds as it alleviated the oxidative stress. Overall, the results of this study suggest the potential of CeNP functionalised PCL-gelatin nanofibrous mesh for wound healing applications.

Rho A and the Rho kinase pathway regulate fibroblast contraction: Enhanced contraction in constitutively active Rho A fibroblast cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nobe, Koji, E-mail: kojinobe@pharm.showa-u.ac.jp; Nobe, Hiromi; Department of Physical Therapy, Bunkyo-Gakuin University

Research highlights: {yields} Mechanisms of fibroblast cell contraction in collagen matrix. {yields} Assessed an isometric force development using 3D-reconstituted-fibroblast fiber. {yields} Constitutively active Rho A induced the over-contraction of fibroblast cells. {yields} Rho A and Rho kinase pathway has a central role in fibroblast cell contraction. -- Abstract: Fibroblast cells play a central role in the proliferation phase of wound healing processes, contributing to force development. The intracellular signaling pathways regulating this non-muscle contraction are only partially understood. To study the relations between Rho A and contractile responses, constitutively active Rho A (CA-Rho A) fibroblast cells were reconstituted into fibersmore » and the effects of calf serum (CS) on isometric force were studied. CS-induced force in CA-Rho A fibroblast fibers was twice as large as that in wild type (NIH 3T3) fibroblast fibers. During this response, the translocation of Rho A from the cytosol to the membrane was detected by Rho A activity assays and Western blot analysis. Pre-treatment with a Rho specific inhibitor (C3-exoenzyme) suppressed translocation as well as contraction. These results indicate that Rho A activation is essential for fibroblast contraction. The Rho kinase inhibitor ( (Y27632)) inhibited both NIH 3T3 and CA-Rho A fibroblast fiber contractions. Activation of Rho A is thus directly coupled with Rho kinase activity. We conclude that the translocation of Rho A from the cytosol to the membrane and the Rho kinase pathway can regulate wound healing processes mediated by fibroblast contraction.« less

Collagenase-labile polyurethane urea synthesis and processing into hollow fiber membranes.

PubMed

Fu, Hui-Li; Hong, Yi; Little, Steven R; Wagner, William R

2014-08-11

As a means to stimulate wound healing, a hollow fiber membrane system might be placed within a wound bed to provide local and externally regulated controlled delivery of regenerative factors. After sufficient healing, it would be desirable to triggerably degrade these fibers as opposed to pulling them out. Accordingly, a series of enzymatically degradable thermoplastic elastomers was developed as potential hollow fiber base material. Polyurethane ureas (PUUs) were synthesized based on 1, 4-diisocyanatobutane, polycaprolactone (PCL) diol and polyethylene glycol (PEG) at different molar fractions as soft segments, and collagenase-sensitive peptide GGGLGPAGGK-NH2 as a chain extender (defined as PUU-CLxEGy-peptide, where x and y are the respective molar percents). In these polymers, PEG in the polymer backbone decreased tensile strengths and initial moduli of solvent-cast films in the wet state, while increasing water absorption. Collagenase degradation was observed at 75% relative PEG content in the soft segment. Control PUUs with putrescine or nonsense peptide chain extenders did not degrade acutely in collagenase. Conduits electrospun from PUU-CL25EG75-peptide and PUU-CL50EG50-peptide exhibited appropriate mechanical strength and sustained release of a model protein from the tube lumen for 7 days. Collapse of PUU-CL25EG75-peptide tubes occurred after collagenase degradation for 3 days. In conclusion, through molecular design, synthesis and characterization, a collagenase-labile PUU-CL25EG75-peptide polymer was identified that exhibited the desired traits of triggerable lability, processability, and the capacity to act as a membrane to facilitate controlled protein release.

Optoelectronic oscillator incorporating hollow-core photonic bandgap fiber.

PubMed

Mutugala, U S; Kim, J; Bradley, T D; Wheeler, N V; Sandoghchi, S R; Hayes, J R; Numkam Fokoua, E; Poletti, F; Petrovich, M N; Richardson, D J; Slavík, R

2017-07-01

We demonstrate, to the best of our knowledge, the first optoelectronic oscillator that uses hollow-core photonic bandgap fiber (HC-PBGF) as a delay element of a sufficient length to allow for low-noise operation. We show experimentally that HC-PBGF can improve the temperature stability of the oscillator by a factor of more than 15, as compared to standard optical fiber. We also measured the oscillator's phase noise, allowing evaluation of the suitability of HC-PBGF for this application. Additionally, this Letter also provides, to the best of our knowledge, the first characterization of the temperature stability of a long length (>800  m in our Letter) of low-thermal sensitivity (2  ps/km/K) HC-PBGF wound on a spool.

Feasibility of speckle variance OCT for imaging cutaneous microvasculature regeneration during healing of wounds in diabetic mice

NASA Astrophysics Data System (ADS)

Sharma, P.; Kumawat, J.; Kumar, S.; Sahu, K.; Verma, Y.; Gupta, P. K.; Rao, K. D.

2018-02-01

We report on a study to assess the feasibility of a swept source-based speckle variance optical coherence tomography setup for monitoring cutaneous microvasculature. Punch wounds created in the ear pinnae of diabetic mice were monitored at different times post wounding to assess the structural and vascular changes. It was observed that the epithelium thickness increases post wounding and continues to be thick even after healing. Also, the wound size assessed by vascular images is larger than the physical wound size. The results show that the developed speckle variance optical coherence tomography system can be used to monitor vascular regeneration during wound healing in diabetic mice.

Stem Cell-Containing Hyaluronic Acid-Based Spongy Hydrogels for Integrated Diabetic Wound Healing.

PubMed

da Silva, Lucília Pereira; Santos, Tírcia Carlos; Rodrigues, Daniel Barreira; Pirraco, Rogério Pedro; Cerqueira, Mariana Teixeira; Reis, Rui Luís; Correlo, Vitor Manuel; Marques, Alexandra Pinto

2017-07-01

The detailed pathophysiology of diabetic foot ulcers is yet to be established and improved treatments are still required. We propose a strategy that directs inflammation, neovascularization, and neoinnervation of diabetic wounds. Aiming to potentiate a relevant secretome for nerve regeneration, stem cells were precultured in hyaluronic acid-based spongy hydrogels under neurogenic/standard media before transplantation into diabetic mice full-thickness wounds. Acellular spongy hydrogels and empty wounds were used as controls. Re-epithelialization was attained 4 weeks after transplantation independently of the test groups, whereas a thicker and more differentiated epidermis was observed for the cellular spongy hydrogels. A switch from the inflammatory to the proliferative phase of wound healing was revealed for all the experimental groups 2 weeks after injury, but a significantly higher M2(CD163 + )/M1(CD86 + ) subtype ratio was observed in the neurogenic preconditioned group that also failed to promote neoinnervation. A higher number of intraepidermal nerve fibers were observed for the unconditioned group probably due to a more controlled transition from the inflammatory to the proliferative phase. Overall, stem cell-containing spongy hydrogels represent a promising approach to enhance diabetic wound healing by positively impacting re-epithelialization and by modulating the inflammatory response to promote a successful neoinnervation. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Topical application of substance P promotes wound healing in streptozotocin-induced diabetic rats.

PubMed

Kant, Vinay; Kumar, Dinesh; Kumar, Dhirendra; Prasad, Raju; Gopal, Anu; Pathak, Nitya N; Kumar, Pawan; Tandan, Surender K

2015-05-01

Substance P (SP) is known to stimulate angiogenesis, fibroblasts proliferation and expressions of cytokines and growth factors involved in wound healing. However, SP level reduces in dermis in diabetics and, hence, it was hypothesized that exogenously applied SP could be helpful in improving wound healing in diabetic rats. Excision skin wound was created on the back of diabetic rats and rats were divided into three groups i.e. (i) saline-, (ii) gel- and (iii) SP-treated. Normal saline, pluronic gel and SP (10(-6)M) in gel were topically applied once daily for 19days. SP treatment significantly increased the wound closure, levels of interleukin-10, and expressions of vascular endothelial growth factor, transforming growth factor-beta1, heme oxygenase-1 and endothelial nitric oxide synthase, whereas it significantly decreased the expression of tumor necrosis factor-alpha, interleukin-1beta and matrix metalloproteinases-9 in the granulation/healing tissue. The inflammatory cells were present for long time in normal saline-treated group. Histological evaluation revealed better extracellular matrix formation with marked fibroblast proliferation and collagen deposition in SP-treated group. Early epithelial layer formation, increased microvessel density and greater growth associated protein-43 positive nerve fibers were also evidenced in SP-treated group. In conclusion, SP treatment markedly accelerated cutaneous wound healing in diabetic rats. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Their Conditioned Media Topically Delivered in Fibrin Glue on Chronic Wound Healing in Rats

PubMed Central

Mehanna, Radwa A.; Nabil, Iman; Attia, Noha; Bary, Amany A.; Razek, Khalid A.; Ahmed, Tamer A. E.; Elsayed, Fatma

2015-01-01

Bone marrow-derived mesenchymal stem cells (BM-MSCs) represent a modern approach for management of chronic skin injuries. In this work, we describe BM-MSCs application versus their conditioned media (CM) when delivered topically admixed with fibrin glue to enhance the healing of chronic excisional wounds in rats. Fifty-two adult male rats were classified into four groups after induction of large-sized full-thickness skin wound: control group (CG), fibrin only group (FG), fibrin + MSCs group (FG + SCs), and fibrin + CM group (FG + CM). Healing wounds were evaluated functionally and microscopically. Eight days after injury, number of CD68+ macrophages infiltrating granulation tissue was considerably higher in the latter two groups. Although—later—none of the groups depicted a substantially different healing rate, the quality of regenerated skin was significantly boosted by the application of either BM-MSCs or their CM both (1) structurally as demonstrated by the obviously increased mean area percent of collagen fibers in Masson's trichrome-stained skin biopsies and (2) functionally as supported by the interestingly improved epidermal barrier as well as dermal tensile strength. Thus, we conclude that topically applied BM-MSCs and their CM—via fibrin vehicle—could effectively improve the quality of healed skin in chronic excisional wounds in rats, albeit without true acceleration of wound closure. PMID:26236740

Dynamics of Cancer Cell near Collagen Fiber Chain

NASA Astrophysics Data System (ADS)

Kim, Jihan; Sun, Bo

Cell migration is an integrated process that is important in life. Migration is essential for embryonic development as well as homeostatic processes such as wound healing and immune responses. When cell migrates through connective extracellular matrix (ECM), it applies cellular traction force to ECM and senses the rigidity of their local environment. We used human breast cancer cell (MDA-MB-231) which is highly invasive and applies strong traction force to ECM. As cancer cell applies traction force to type I collage-based ECM, it deforms collagen fibers near the surface. Patterns of deforming collagen fibers are significantly different with pairs of cancer cells compared to a single cancer cell. While a pair of cancer cells within 60 um creates aligned collagen fiber chains between them permanently, a single cancer cell does not form any fiber chains. In this experiment we measured a cellular response and an interaction between a pair of cells through the chain. Finally, we analyzed correlation of directions between cancer cell migration and the collagen chain alignment.

FIBER OPTICS. ACOUSTOOPTICS: High-frequency magnetooptics of fiber waveguides

NASA Astrophysics Data System (ADS)

Antonov, S. N.; Bulyuk, A. N.; Vetoshko, P. M.; Shkerdin, G. N.

1990-07-01

An investigation is made of the hf distributed magnetooptic interaction in fiber waveguides associated with the Faraday effect observed under the conditions of both spatial and temporal phase matching between the normal modes of the waveguide and an external magentic field. Analytic expressions are obtained for the main relationships governing modulation of the state of polarization of light in a long fiber waveguide at high and ultrahigh frequencies. An analysis is made of several variants of hf magnetooptic modulators. It is shown that in the specific case when a 10-m long quartz fiber waveguide wound to form a cylindrical coil is placed inside the cavity of a coaxial microwave resonator and the microwave control power is 10 W, the efficiency of modulation of light should be 50%. The main theoretical predictions were supported by the reported experiments. These experiments showed that at a frequency of 80 MHz the modulation efficiency was 1% when the control power was 0.5 W.

Stretchable Optomechanical Fiber Sensors for Pressure Determination in Compressive Medical Textiles.

PubMed

Sandt, Joseph D; Moudio, Marie; Clark, J Kenji; Hardin, James; Argenti, Christian; Carty, Matthew; Lewis, Jennifer A; Kolle, Mathias

2018-05-29

Medical textiles are widely used to exert pressure on human tissues during treatment of post-surgical hematoma, burn-related wounds, chronic venous ulceration, and other maladies. However, the inability to dynamically sense and adjust the applied pressure often leads to suboptimal pressure application, prolonging treatment or resulting in poor patient outcomes. Here, a simple strategy for measuring sub-bandage pressure by integrating stretchable optomechanical fibers into elastic bandages is demonstrated. Specifically, these fibers possess an elastomeric photonic multilayer cladding that surrounds an extruded stretchable core filament. They can sustain repetitive strains of over 100%, and respond to deformation with a predictable and reversible color variation. Integrated into elastic textiles, which apply pressure as a function of their strain, these fibers can provide instantaneous and localized pressure feedback. These colorimetric fiber sensors are well suited for medical textiles, athletic apparel, and other smart wearable technologies, especially when repetitive, large deformations are required. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ear wound regeneration in the African spiny mouse Acomys cahirinus

PubMed Central

Matias Santos, Dino; Rita, Ana Martins; Casanellas, Ignasi; Brito Ova, Adélia; Araújo, Inês Maria; Power, Deborah

2016-01-01

Abstract While regeneration occurs in a number of taxonomic groups across the Metazoa, there are very few reports of regeneration in mammals, which generally respond to wounding with fibrotic scarring rather than regeneration. A recent report described skin shedding, skin regeneration and extensive ear punch closure in two rodent species, Acomys kempi and Acomys percivali. We examined these striking results by testing the capacity for regeneration of a third species, Acomys cahirinus, and found a remarkable capacity to repair full thickness circular punches in the ear pinna. Four‐millimeter‐diameter wounds closed completely in 2 months in 100% of ear punches tested. Histology showed extensive formation of elastic cartilage, adipose tissue, dermis, epidermis and abundant hair follicles in the repaired region. Furthermore, we demonstrated abundant angiogenesis and unequivocal presence of both muscle and nerve fibers in the reconstituted region; in contrast, similar wounds in C57BL/6 mice simply healed the borders of the cut by fibrotic scarring. Our results confirm the regenerative capabilities of Acomys, and suggest this model merits further attention. PMID:27499879

Comparative Analysis of Single-Species and Polybacterial Wound Biofilms Using a Quantitative, In Vivo, Rabbit Ear Model

DTIC Science & Technology

2012-08-08

Research, Fort Sam Houston, San Antonio, Texas, United States of America Abstract Introduction: The recent literature suggests that chronic wound...Introduction The management and treatment of chronic wounds continues to be a significant burden on the healthcare system [1–6]. The importance of bacterial...8, 2012 14. ABSTRACT Introduction: The recent literature suggests that chronic wound biofilms often consist of multiple bacterial species. However

Bioelectromagnetics 2005

DTIC Science & Technology

2006-08-14

fields in wound healing and nerve regeneration; 2) ultrashort high voltage pulses for tumor treatment; 3) therapeutic uses of magnetic fields; 4...7 Session 3: Role Of Electric Fields In Wound Healing And Nerve Regeneration (Continued)..........26 Session 4: Exposure...8 Bioelectromagnetics 2005, Dublin, Ireland Session 1: Role Of Electric Fields In Wound Healing And Nerve Regeneration Chairs: Richard

Neck dissection - discharge

MedlinePlus

... you are recovering. Other Self-care You will need to learn to care for your wound . You may get special antibiotic cream in the hospital to rub on your wound. Continue to do this 2 or 3 times a day after you go home. You can shower after you return home. Wash your wound gently with soap and ...

Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

NASA Technical Reports Server (NTRS)

Kohlman, Lee W.

2013-01-01

Toughening and other property enhancements of composite materials are typically implemented by-modifying the bulk properties of the constituents, either the fiber or matrix materials. This often leads to difficulties in processing and higher material costs. Many composites consist of tows or yarns (thousands of individual fibers) that are either filament wound or processed into a fabric by weaving or braiding. The matrix material can be added to the tow or fabric before final processing, resulting in a prepreg material, or infused into the fiber material during final processing by a variety of methods. By using a direct electrospun deposition method to apply thermoplastic nanofiber to the surface of the tows, the tow-tow interface in the resulting composite can be modified while using otherwise conventional materials and handling processes. Other materials of interest could also be incorporated into the electrospun precursor.

Test methods and design allowables for fibrous composites. Volume 2

NASA Technical Reports Server (NTRS)

Chamis, Christos C. (Editor)

1989-01-01

Topics discussed include extreme/hostile environment testing, establishing design allowables, and property/behavior specific testing. Papers are presented on environmental effects on the high strain rate properties of graphite/epoxy composite, the low-temperature performance of short-fiber reinforced thermoplastics, the abrasive wear behavior of unidirectional and woven graphite fiber/PEEK, test methods for determining design allowables for fiber reinforced composites, and statistical methods for calculating material allowables for MIL-HDBK-17. Attention is also given to a test method to measure the response of composite materials under reversed cyclic loads, a through-the-thickness strength specimen for composites, the use of torsion tubes to measure in-plane shear properties of filament-wound composites, the influlence of test fixture design on the Iosipescu shear test for fiber composite materials, and a method for monitoring in-plane shear modulus in fatigue testing of composites.

Bactericidal Activity of Usnic Acid-Loaded Electrospun Fibers.

PubMed

Araújo, Evando S; Pereira, Eugênia C; da Costa, Mateus M; da Silva, Nicácio H; de Oliveira, Helinando P

2016-01-01

Usnic acid has been progressively reported in the literature as one of the most important lichen metabolites characterized by a rich diversity of applications such as antifungal, antimicrobial, antiprotozoal and antiviral agent. Particularly, antimicrobial activity of usnic acid can be improved by encapsulation of active molecules in enteric electrospun fibers, allowing the controlled release of active molecule at specific pH. Few relevant patents to the topic have been reviewed and cited. Bactericidal activity of usnic acid-loaded electrospun fibers of Eudragit L-100 and polyvinylpyrrolidone was examined against Staphylococcus aureus using inhibition hales methodology. The controlled release of active material at high pH is established after 10 minutes of interaction with media and results in reasonable activity against S. aureus, as detected by inhibition hales. The strong biological activity of usnic acid-loaded electrospun fibers provides a promising application for corresponding material as a bactericidal agent for wound healing treatment.

In vivo low-level light therapy increases cytochrome oxidase in skeletal muscle.

PubMed

Hayworth, Christopher R; Rojas, Julio C; Padilla, Eimeira; Holmes, Genevieve M; Sheridan, Eva C; Gonzalez-Lima, F

2010-01-01

Low-level light therapy (LLLT) increases survival of cultured cells, improves behavioral recovery from neurodegeneration and speeds wound healing. These beneficial effects are thought to be mediated by upregulation of mitochondrial proteins, especially the respiratory enzyme cytochrome oxidase. However, the effects of in vivo LLLT on cytochrome oxidase in intact skeletal muscle have not been previously investigated. We used a sensitive method for enzyme histochemistry of cytochrome oxidase to examine the rat temporalis muscle 24 h after in vivo LLLT. The findings showed for the first time that in vivo LLLT induced a dose- and fiber type-dependent increase in cytochrome oxidase in muscle fibers. LLLT was particularly effective at enhancing the aerobic capacity of intermediate and red fibers. The findings suggest that LLLT may enhance the oxidative energy metabolic capacity of different types of muscle fibers, and that LLLT may be used to enhance the aerobic potential of skeletal muscle.

A helical scintillating fiber hodoscope

NASA Astrophysics Data System (ADS)

Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Bissel, T.; Bollmann, R.; Busch, M.; Büßer, K.; Colberg, T.; Demirörs, L.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Eversheim, P. D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Hinterberger, F.; Jahn, R.; Jeske, M.; Jonas, E.; Krause, H.; Lahr, U.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuck, T.; Meinerzhagen, A.; Nähle, O.; Pfuff, M.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Sanz, B.; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Thomas, S.; Trelle, H. J.; Weise, E.; Wellinghausen, A.; Wiedmann, W.; Woller, K.; Ziegler, R.; EDDA Collaboration

1999-07-01

A novel scintillating fiber hodoscope in helically cylindric geometry has been developed for detection of low multiplicity events of fast protons and other light charged particles in the internal target experiment EDDA at the Cooler Synchrotron COSY. The hodoscope consists of 640 scintillating fibers (2.5 mm diameter), arranged in four layers surrounding the COSY beam pipe. The fibers are helically wound in opposing directions and read out individually using 16-channel photomultipliers connected to a modified commercial encoding system. The detector covers an angular range of 9°⩽ Θ⩽72° and 0°⩽ ϕ⩽360° in the lab frame. The detector length is 590 mm, the inner diameter 161 mm. Geometry and granularity of the hodoscope afford a position resolution of about 1.3 mm. The detector design took into consideration a maximum of reliability and a minimum of maintenance. An LED array may be used for monitoring purposes.

Optimizing the Moisture Management Tightrope with Wound Bed Preparation 2015©.

PubMed

Sibbald, R Gary; Elliott, James A; Ayello, Elizabeth A; Somayaji, Ranjani

2015-10-01

To provide an overview of moisture management and its importance in wound care. This continuing education activity is intended for physicians and nurses with an interest in skin and wound care. After participating in this educational activity, the participant should be better able to:1. Summarize causes and treatments for moisture balance issues of chronic wounds.2. Recognize the properties of dressings used for treatment for moisture management of chronic wounds and antiseptic agent cytotoxicity.3. Explain study findings of the effectiveness of dressing choices for treatment of chronic wounds. To provide an overview of moisture management and its importance in wound care. The authors evaluate the impact of moisture management for optimal wound care and assess current wound management strategies relating to antisepsis and moist wound healing utilizing the wound bed preparation paradigm 2015 update. The discussion distinguishes the form and function of wound care dressing classes available for optimal moisture management. Moisture management for chronic wounds is best achieved with modern moist interactive dressings if the wound has the ability to heal.

64.1: Display Technologies for Therapeutic Applications of Virtual Reality

PubMed Central

Hoffman, Hunter G.; Schowengerdt, Brian T.; Lee, Cameron M.; Magula, Jeff; Seibel, Eric J.

2015-01-01

A paradigm shift in image source technology for VR helmets is needed. Using scanning fiber displays to replace LCD displays creates lightweight, safe, low cost, wide field of view, portable VR goggles ideal for reducing pain during severe burn wound care in hospitals and possibly in austere combat-transport environments. PMID:26146424

System to continuously produce carbon fiber via microwave assisted plasma processing

DOEpatents

White, Terry L [Knoxville, TN; Paulauskas, Felix L [Knoxville, TN; Bigelow, Timothy S [Knoxville, TN

2010-11-02

A system to continuously produce fully carbonized or graphitized carbon fibers using microwave-assisted plasma (MAP) processing comprises an elongated chamber in which a microwave plasma is excited in a selected gas atmosphere. Fiber is drawn continuously through the chamber, entering and exiting through openings designed to minimize in-leakage of air. There is a gradient of microwave power within the chamber with generally higher power near where the fiber exits and lower power near where the fiber enters. Polyacrylonitrile (PAN), pitch, or any other suitable organic/polymeric precursor fibers can be used as a feedstock for the inventive system. Oxidized or partially oxidized PAN or pitch or other polymeric fiber precursors are run continuously through a MAP reactor in an inert, non-oxidizing atmosphere to heat the fibers, drive off the unwanted elements such as oxygen, nitrogen, and hydrogen, and produce carbon or graphite fibers faster than conventionally produced carbon fibers.

Treatment of hardware infection after osteosynthesis of lower leg using negative pressure wound therapy and transforming powder dressing.

PubMed

Marinović, Marin; Ivandcić, Aldo; Spanjol, Josip; Pina, Maja; Bakota, Bore; Bandalović, Ante; Cukeljs, Fabijan

2014-12-01

Fractures of the distal part of the lower leg are more common in everyday practice and traumatology. In young and active patients these injuries are mainly caused by high energy trauma. They are treated with external fixator in first step, and in second step, after sanation of the soft tissue, with open reduction and internal fixation (ORIF). It is very safe and effective method of treatment. Treatment of the infections that occur in the early postoperative period after open reduction and internal fixation represents a great problem and challenge for surgeons. It is widely accepted that the presence of deep infection can't be cured in the presence of hardware. However, removal of hardware in the presence of unhealed fractures significantly complicates sanation of infection and fracture itself We have decided to present a 35-years-old patient with a hardware infection with present chronic wound with hardware exposed eight months after the first operation and six months after second operation. The wound measured one centimeter in diameter with cell detritus and bad granulations tissue inside the wound. Hardwre was exposed in the depth of the wound.The secretion was minimal. Negative Pressure Wound Therapy (NPWT) was applicated after debridemet and lavage performed in ambulatory conditions. The starting therapy was continuously -125 mm Hg of vacuum. After five days of NPWT the defect was partially filled with granula- tion tissue. For another five days we continue with NPWT with the same values of-125 mm Hg pressure but in the inter- mitent mode. After that period we used transforming powder dressing for covering and protection of the wound with was filled with granulation tissue. Five days later, wound was completely healed with epithelisation. After four months of patient follow-up, we found the wound is completely repaired. The patient denies pain and has continued orderly flow of fracture healing, with no signs of infection.

Effects of protein-coated nanofibers on conformation of gingival fibroblast spheroids: potential utility for connective tissue regeneration.

PubMed

Kaufman, Gili; Whitescarver, Ryan A; Nunes, Laiz; Palmer, Xavier-Lewis; Skrtic, Drago; Tutak, Wojtek

2018-01-24

Deep wounds in the gingiva caused by trauma or surgery require a rapid and robust healing of connective tissues. We propose utilizing gas-brushed nanofibers coated with collagen and fibrin for that purpose. Our hypotheses are that protein-coated nanofibers will: (i) attract and mobilize cells in various spatial orientations, and (ii) regulate the expression levels of specific extracellular matrix (ECM)-associated proteins, determining the initial conformational nature of dense and soft connective tissues. Gingival fibroblast monolayers and 3D spheroids were cultured on ECM substrate and covered with gas-blown poly-(DL-lactide-co-glycolide) (PLGA) nanofibers (uncoated/coated with collagen and fibrin). Cell attraction and rearrangement was followed by F-actin staining and confocal microscopy. Thicknesses of the cell layers, developed within the nanofibers, were quantified by ImageJ software. The expression of collagen1α1 chain (Col1α1), fibronectin, and metalloproteinase 2 (MMP2) encoding genes was determined by quantitative reverse transcription analysis. Collagen- and fibrin- coated nanofibers induced cell migration toward fibers and supported cellular growth within the scaffolds. Both proteins affected the spatial rearrangement of fibroblasts by favoring packed cell clusters or intermittent cell spreading. These cell arrangements resembled the structural characteristic of dense and soft connective tissues, respectively. Within three days of incubation, fibroblast spheroids interacted with the fibers, and grew robustly by increasing their thickness compared to monolayers. While the ECM key components, such as fibronectin and MMP2 encoding genes, were expressed in both protein groups, Col1α1 was predominantly expressed in bundled fibroblasts grown on collagen fibers. This enhanced expression of collagen1 is typical for dense connective tissue. Based on results of this study, our gas-blown, collagen- and fibrin-coated PLGA nanofibers are viable candidates for engineering soft and dense connective tissues with the required structural characteristics and functions needed for wound healing applications. Rapid regeneration of these layers should enhance healing of open wounds in a harsh oral environment.

Animal models of external traumatic wound infections

PubMed Central

Dai, Tianhong; Kharkwal, Gitika B; Tanaka, Masamitsu; Huang, Ying-Ying; Bil de Arce, Vida J

2011-01-01

Background: Despite advances in traumatic wound care and management, infections remain a leading cause of mortality, morbidity and economic disruption in millions of wound patients around the world. Animal models have become standard tools for studying a wide array of external traumatic wound infections and testing new antimicrobial strategies. Results: Animal models of external traumatic wound infections reported by different investigators vary in animal species used, microorganism strains, the number of microorganisms applied, the size of the wounds and for burn infections, the length of time the heated object or liquid is in contact with the skin. Methods: This review covers experimental infections in animal models of surgical wounds, skin abrasions, burns, lacerations, excisional wounds and open fractures. Conclusions: As antibiotic resistance continues to increase, more new antimicrobial approaches are urgently needed. These should be tested using standard protocols for infections in external traumatic wounds in animal models. PMID:21701256

Fiber Reinforced Composite Materials Used for Tankage

NASA Technical Reports Server (NTRS)

Cunningham, Christy

2005-01-01

The Nonmetallic Materials and Processes Group is presently working on several projects to optimize cost while providing effect materials for the space program. One factor that must be considered is that these materials must meet certain weight requirements. Composites contribute greatly to this effort. Through the use of composites the cost of launching payloads into orbit will be reduced to one-tenth of the current cost. This research project involved composites used for aluminum pressure vessels. These tanks are used to store cryogenic liquids during flight. The tanks need some type of reinforcement. Steel was considered, but added too much weight. As a result, fiber was chosen. Presently, only carbon fibers with epoxy resin are wrapped around the vessels as a primary source of reinforcement. Carbon fibers are lightweight, yet high strength. The carbon fibers are wet wound onto the pressure vessels. This was done using the ENTEC Filament Winding Machine. It was thought that an additional layer of fiber would aid in reinforcement as well as containment and impact reduction. Kevlar was selected because it is light weight, but five times stronger that steel. This is the same fiber that is used to make bullet-proof vests trampolines, and tennis rackets.

A MYB/ZML Complex Regulates Wound-Induced Lignin Genes in Maize

PubMed Central

Vélez-Bermúdez, Isabel-Cristina; Salazar-Henao, Jorge E.; Franco-Zorrilla, José-Manuel; Grotewold, Erich; Solano, Roberto

2015-01-01

Lignin is an essential polymer in vascular plants that plays key structural roles in vessels and fibers. Lignification is induced by external inputs such as wounding, but the molecular mechanisms that link this stress to lignification remain largely unknown. In this work, we provide evidence that three maize (Zea mays) lignin repressors, MYB11, MYB31, and MYB42, participate in wound-induced lignification by interacting with ZML2, a protein belonging to the TIFY family. We determined that the three R2R3-MYB factors and ZML2 bind in vivo to AC-rich and GAT(A/C) cis-elements, respectively, present in a set of lignin genes. In particular, we show that MYB11 and ZML2 bind simultaneously to the AC-rich and GAT(A/C) cis-elements present in the promoter of the caffeic acid O-methyl transferase (comt) gene. We show that, like the R2R3-MYB factors, ZML2 also acts as a transcriptional repressor. We found that upon wounding and methyl jasmonate treatments, MYB11 and ZML2 proteins are degraded and comt transcription is induced. Based on these results, we propose a molecular regulatory mechanism involving a MYB/ZML complex in which wound-induced lignification can be achieved by the derepression of a set of lignin genes. PMID:26566917

Comparison of the effects of the CO2 laser and chlorohexidine on the sterilization of infected cutaneous wounds: a histologic study

NASA Astrophysics Data System (ADS)

Pinheiro, Antonio L. B.; das Neves, Jerlucia C.; de Castro, Jurema F. L.; Santos, Jose Z. L. V.; Ribeiro de Sena, Kesia X. d. F.; Brugnera, Aldo, Jr.; Zanin, Fatima A. A.

2001-04-01

Wound infection constitutes a big risk for patients and it is usually associated to increased morbidity, mortality and hospital costs. It is accepted that local treatment of these infections is effective. The aim of this study was to compare histologically the effects of the CO2 laser and Chlorohexidine Gluconate on Staphylococcus aureus infected cutaneous wounds. Standardized wounds were infected with Staphylococcus aureus and treated during six days as follows: Group I: Chlorohexidine Gluconate, 1 min, six days; Group II: CO2 Laser, one day, maintaining surface debris; Group III: CO2 Laser, one day, removing the surface debris. Seven days after wounding the animals were killed and specimens taken for light microscopy. On control wounds, it was observed epithelial ulceration, and neutrophylic and lymphoplasmocitary inflammatory infiltrate. On group II, there was epithelial hyperplasia, areas of ulceration and intense neutrophylic and lymphoplasmocitary inflammatory infiltrate. On the other hand, on group III, there was a neutrophylic inflammatory infiltrate underneath the surface debris and below that intense lymphoplasmocitary inflammatory infiltrate. When the surface debris was removed, there was epithelial ulceration and mild lymphoplasmocitary inflammatory infiltrate and fibroblasts and collagen fibers. The result of this study shows that infected wounds treated with 4 percent Chlorohexidine shows a more pronounced inflammatory reaction when compared to that observed when the CO2 Laser is used, especially when surface debris are removed; Surface debris removal on Laser treated wounds results ona better and quicker healing; the surface debris may act as a culture medium for bacterial growth, or because of its characteristics, it may act as local irritant and delay healing.

PED/PEA-15 Controls Fibroblast Motility and Wound Closure by ERK1/2-Dependent Mechanisms

PubMed Central

Buonomo, Roberta; Giacco, Ferdinando; Vasaturo, Angela; Caserta, Sergio; Guido, Stefano; Pagliara, Valentina; Garbi, Corrado; Mansueto, Gelsomina; Cassese, Angela; Perruolo, Giuseppe; Oriente, Francesco; Miele, Claudia; Beguinot, Francesco; Formisano, Pietro

2012-01-01

Cell migration is dependent on the control of signaling events that play significant roles in creating contractile force and in contributing to wound closure. We evaluated wound closure in fibroblasts from mice overexpressing (TgPED) or lacking ped/pea-15 (KO), a gene overexpressed in patients with type 2 diabetes. Cultured skin fibroblasts isolated from TgPED mice showed a significant reduction in the ability to recolonize wounded area during scratch assay, compared to control fibroblasts. This difference was observed both in the absence and in the presence of mytomicin C, an inhibitor of mitosis. In time-lapse experiments, TgPED fibroblasts displayed about twofold lower velocity and diffusion coefficient, as compared to controls. These changes were accompanied by reduced spreading and decreased formation of stress fibers and focal adhesion plaques. At the molecular level, TgPED fibroblasts displayed decreased RhoA activation and increased abundance of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2). Inhibition of ERK1/2 activity by PD98059 restored RhoA activation, cytoskeleton organization and cell motility, and almost completely rescued wound closure of TgPED fibroblasts. Interestingly, skin fibroblasts isolated from KO mice displayed an increased wound closure ability. In vivo, healing of dorsal wounds was delayed in TgPED and accelerated in KO mice. Thus, PED/PEA-15 may affect fibroblast motility by a mechanism, at least in part, mediated by ERK1/2. J. Cell. Physiol. 227: 2106–2116, 2012. © 2011 Wiley Periodicals, Inc. PMID:21780113

Enamel Matrix Derivative Promotes Healing of a Surgical Wound in the Rat Oral Mucosa.

PubMed

Maymon-Gil, Tal; Weinberg, Evgeny; Nemcovsky, Carlos; Weinreb, Miron

2016-05-01

Enamel matrix proteins (EMPs) play a role in enamel formation and the development of the periodontium. Sporadic clinical observations of periodontal regeneration treatments with enamel matrix derivative (EMD), a commercial formulation of EMPs, suggest that it also promotes post-surgical healing of soft tissues. In vitro studies showed that EMD stimulates various cellular effects, which could potentially enhance wound healing. This study examines the in vivo effects of EMD on healing of an oral mucosa surgical wound in rats. A bilateral oral mucosa wound was created via a crestal incision in the anterior edentulous maxilla of Sprague-Dawley rats. Full-thickness flaps were raised, and, after suturing, EMD was injected underneath the soft tissues on one side, whereas the EMD vehicle was injected in the contralateral side. Animals were sacrificed after 5 or 9 days, and the wound area was subjected to histologic and immunohistochemical analysis of the epithelial gap, number of macrophages, blood vessels, proliferating cells, and collagen content in the connective tissue (CT). Gene expression analysis was also conducted 2 days post-surgery. EMD had no effect on the epithelial gap of the wound. On both days 5 and 9, EMD treatment increased significantly the number of blood vessels and the collagen content. EMD also enhanced (by 20% to 40%) the expression of transforming growth factors β1 and β2, vascular endothelial growth factor, interleukin-1β, matrix metalloproteinase-1, versican, and fibronectin. EMD improves oral mucosa incisional wound healing by promoting formation of blood vessels and collagen fibers in CT.

Modified cotton gauze dressings that selectively absorb neutrophil elastase activity in solution.

PubMed

Edwards, J V; Yager, D R; Cohen, I K; Diegelmann, R F; Montante, S; Bertoniere, N; Bopp, A F

2001-01-01

Dressings for chronic human wounds have been aimed at protection, removal of exudate, and improved appearance. However since the time of ancient Greece wound care and dressing strategies have primarily relied on empiricism. Recent studies have shown that chronic wounds contain high levels of tissue and cytokine destroying proteases including collagenase and neutrophil elastase. Therefore we sought to develop an effective wound dressing that could absorb elastase through affinity sequestration. Cotton gauze was modified by oxidation, phosphorylation, and sulfonation to enhance elastase affinity by ionic or active site uptake. Type VII absorbent cotton gauze was oxidized to dialdehyde cotton which was subsequently converted in part to the bisulfite addition product. Gauze preparations were also phosphorylated and carboxymethylated. Modified cotton gauzes were compared with untreated gauze for reduction of elastase activity in buffered saline. Solutions of elastase that were soaked in oxidized, sulfonated, and phosphorylated cotton gauze showed reduced elastase activity. The initial velocities (v(o)) and turnover rates of elastase showed significant decreases compared with solutions taken from untreated gauze. The reduction in enzyme activity with dialdehyde cotton gauze was confirmed in solution by determining elastase inhibition with dialdehyde starch. The dialdehyde cotton gauze also decreased elastase activity in human wound fluid in a dose response relation based on weight of gauze per volume of wound fluid. Absorbency, pH, air permeability and strength properties of the modified gauze were also compared with untreated cotton gauze. This report shows the effect of reducing elastase activity in solution with cotton containing aldehydic or negatively charged cellulose fibers that may be applicable to treatment modalities in chronic wounds.

Spatiotemporal dynamics of actin remodeling and endomembrane trafficking in alveolar epithelial type I cell wound healing

PubMed Central

Godin, Lindsay M.; Vergen, Jorge; Prakash, Y. S.; Pagano, Richard E.

2011-01-01

Alveolar epithelial type I cell (ATI) wounding is prevalent in ventilator-injured lungs and likely contributes to pathogenesis of “barotrauma” and “biotrauma.” In experimental models most wounded alveolar cells repair plasma membrane (PM) defects and survive insults. Considering the force balance between edge energy at the PM wound margins and adhesive interactions of the lipid bilayer with the underlying cytoskeleton (CSK), we tested the hypothesis that subcortical actin depolymerization is a key facilitator of PM repair. Using real-time fluorescence imaging of primary rat ATI transfected with a live cell actin-green fluorescent protein construct (Lifeact-GFP) and loaded with N-rhodamine phosphatidylethanolamine (PE), we examined the spatial and temporal coordination between cytoskeletal remodeling and PM repair following micropuncture. Membrane integrity was inferred from the fluorescence intensity profiles of the cytosolic label calcein AM. Wounding led to rapid depolymerization of the actin CSK near the wound site, concurrent with accumulation of endomembrane-derived N-rhodamine PE. Both responses were sustained until PM integrity was reestablished, which typically occurs between ∼10 and 40 s after micropuncture. Only thereafter did the actin CSK near the wound begin to repolymerize, while the rate of endomembrane lipid accumulation decreased. Between 60 and 90 s after successful PM repair, after translocation of the actin nucleation factor cortactin, a dense actin fiber network formed. In cells that did not survive micropuncture injury, actin remodeling did not occur. These novel results highlight the importance of actin remodeling in ATI cell repair and suggest molecular targets for modulating the repair process. PMID:21216977

5α-Dihydrotestosterone enhances wound healing in diabetic rats.

PubMed

Gonçalves, Reggiani V; Novaes, Rômulo D; Sarandy, Mariáurea M; Damasceno, Eduardo M; da Matta, Sérgio L P; de Gouveia, Neire M; Freitas, Mariella B; Espindola, Foued S

2016-05-01

Wound healing involves a complex interaction between the cells, extracellular matrix and oxidative response. Analyze the effects of 5α-Dihydrotestosterone (5α-DTH) ointment in cutaneous wound healing by secondary intention in diabetic Wistar rats. Rats (302.23±26.23g, n=48) were maintained in cages with food and water ad libitum in accordance with the Guiding Principles in the Use of Animal Ethics Committee. Diabetes was induced by intraperitoneal injection of streptozotocin (60mg/kg). Three skin wounds (12mm diameter) were created on the animals' back, which were randomized into 6 groups according to the application received: VT group: Vehicle (lanolin), SA group: 0.9% saline solution, NC group: Non-diabetic, CP group: positive control (silver sulfadiazine 0001%), T1 group: Testosterone (10%), T2 group: Testosterone (20%) emulsified in lanolin. The applications were made daily within 21days, and tissues from different wounds were removed every 7days. Both groups treated with testosterone (T1 and T2) showed a significantly higher proportion of type I and type III collagen fibers. Superoxide dismutase levels were significantly higher on days 7 and 14 in testosterone treated groups. Protein carbonyls and MDA were lower in both groups. We conclude that groups treated with 5α-DTH showed a better healing pattern with complete wound closure, and proved to have a positive effect on the morphology of the scar tissue as well as an antioxidant stimulating effect during secondhand intention skin wounds repair in diabetic rats. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of Chicken-Egg Membrane as a Dressing for Wound Healing.

PubMed

Guarderas, Fernando; Leavell, Yaowaree; Sengupta, Trisha; Zhukova, Mariya; Megraw, Timothy L

2016-03-01

To examine the efficacy of the folk remedy of chicken-egg membrane dressing on wound healing. Full-thickness excisional wounds were created on 14 male Sprague-Dawley rats in 2 separate trials. Each animal received 2 wounds on the upper back. One wound was untreated, and the other was dressed with chicken-egg membrane to assess its impact on wound healing. Half of the rats received egg membrane treatment on the inferior wound, whereas the other half received egg membrane treatment on the superior wound. Membrane replacement, wound debridement, and imaging were done on days 5, 8, and 10 and then imaging continued on days 12, 14, 16, 18, and 20 of the experiment. Healing rate was measured based on the wound area over the 20 days of the experiment. The wounds dressed with chicken-egg membrane had a significantly (P < .01) faster rate of healing compared with the control at the early stages of healing between days 0 and 5. This group healed 21% faster during this early phase, compared with the control group. Overall, however, wound healing rates were indistinguishable from days 5 to 20. Chicken-egg membrane dressing significantly improves healing of cutaneous wounds in the early stages of wound healing.

Use of Negative-Pressure Wound Therapy in Orthopaedic Trauma

DTIC Science & Technology

2012-09-01

sponge, and continuous suction is applied at −50 mm Hg. NPWT is discontinued after 2 to 5 days. Split-thickness Skin Graft When placing a NPWT dressing...over a split-thickness skin graft (STSG), we apply a single sheet of nonadher- ent dressing to the wound to provide a barrier between the STSG and the...trauma, including surgical incisions at increased risk of breakdown or in- fection, skin grafts , and infected wounds.21,22 Wounds With Associated Soft

[Surgical anatomy of the peri-insular association tracts. Part I.The superior longitudinal fascicle system].

PubMed

Bykanov, A E; Pitskhelauri, D I; Batalov, A I; Pronin, I N; Shkarubo, M A; Dobrovol'sky, G F; Kobyakov, G L; Buklina, S B; Puchkov, V L; Zakharova, N E; Smirnov, A S; Sanikidze, A Z; Gol'bin, D A; Pogosbekyan, E L; Kudieva, E S; Shkatova, A M; Potapov, A A

To study the peri-insular association tract anatomy and define the permissible anatomical boundaries for resection of glial insular tumors with allowance for the surgical anatomy of the peri-insular association tracts. In an anatomic study of the superior longitudinal fascicle system (SLF I, SLF II, SLF III, arcuate fascicle), we used 12 anatomical specimens (6 left and 6 right hemispheres) prepared according to the Klingler's fiber dissection technique. To confirm the dissection data, we used MR tractography (HARDI-CSD-tractography) of the conduction tracts, which was performed in two healthy volunteers. Except the SLF I (identified in 7 hemispheres by fiber dissection), all fascicles of the SLF system were found in all investigated hemispheres by both fiber dissection and MR tractography. The transcortical approach to the insula through the frontal and (or) parietal operculum is associated with a significant risk of transverse transection of the SLF III fibers passing in the frontal and parietal opercula. The most optimal area for the transcortical approach to the insula is the anterior third of the superior temporal gyrus that lacks important association tracts and, consequently, a risk of their injury. The superior peri-insular sulcus is an intraoperative landmark for the transsylvian approach, which enables identification of the SLF II and arcuate fascicle in the surgical wound. Detailed knowledge of the peri-insular association tract anatomy is the prerequisite for neurosurgery in the insular region. Our findings facilitate correct identification of both the site for cerebral operculum dissection upon the transcortical approach and the intraoperative landmarks for locating the association tracts in the surgical wound upon the transsylvian approach to the insula.

Osteomyelitis: A Context for Wound Management.

PubMed

Groll, Mary E; Woods, Timothy; Salcido, Richard

2018-06-01

To provide an overview of osteomyelitis. This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. After completing this continuing education activity, you should be able to:1. Distinguish the pathogenesis of osteomyelitis in children and adults.2. Identify practical considerations for diagnosis and evidence-based treatment of osteomyelitis. This educational activity reviews the pathogenesis of osteomyelitis and discusses practical considerations for diagnosis, treatment, and functional rehabilitation of pediatric and adult patients with osteomyelitic wounds. Antibiotic, surgical, and adjunctive treatments will be addressed. Emphasis is placed on consulting with infectious disease specialists and using evidence-based guidelines for antibiotic prescribing.

Gender and Suicide Risk: The Role of Wound Site

ERIC Educational Resources Information Center

Stack, Steven; Wasserman, Ira

2009-01-01

That males have higher suicide rates than females is one of the most empirically documented social facts in suicidology, but the reasons for this continue to be debated. For the present paper, we tested a neglected contributing factor to the gender suicide ratio: wound site or the area of the body that is wounded in firearm suicides. Males may…

Ultrasonic assisted consolidation of commingled thermoplastic/glass fibers rovings

NASA Astrophysics Data System (ADS)

Lionetto, Francesca; Dell'Anna, Riccardo; Montagna, Francesco; Maffezzoli, Alfonso

2015-04-01

Thermoplastic matrix composites are finding new applications in different industrial area thanks to their intrinsic advantages related to environmental compatibility and processability. The approach presented in this work consists in the development of a technology for the simultaneous deposition and consolidation of commingled thermoplastic rovings through to the application of high energy ultrasound. An experimental equipment, integrating both fiber impregnation and ply consolidation in a single process, has been designed and tested. It is made of an ultrasonic welder, whose titanium sonotrode is integrated on a filament winding machine. During winding, the commingled roving is at the same time in contact with the mandrel and the horn. The intermolecular friction generated by ultrasound is able to melt the thermoplastic matrix and impregnate the reinforcement fibers. The heat transfer phenomena occurring during the in situ consolidation were simulated solving by finite element (FE) analysis an energy balance accounting for the heat generated by ultrasonic waves and the melting characteristics of the matrix. To this aim, a calorimetric characterization of the thermoplastic matrix has been carried out to obtain the input parameters for the model. The FE analysis has enabled to predict the temperature distribution in the composite during heating and cooling The simulation results have been validated by the measurement of the temperature evolution during ultrasonic consolidation. The reliability of the developed consolidation equipment was proved by producing hoop wound cylinder prototypes using commingled continuous E-glass rovings and Polypropylene (PP) filaments. The consolidated composite cylinders are characterized by high mechanical properties, with values comparable with the theoretical ones predicted by the micromechanical analysis.

Cell-populated collagen lattice contraction model for the investigation of fibroblast collagen interactions.

PubMed

Ehrlich, H Paul; Moyer, Kurtis E

2013-01-01

The fibroblast-populated collagen lattice (FPCL) was intended to act as the dermal component for "skin-equivalent" or artificial skin developed for skin grafting burn patients. The "skin-equivalent" was clinically unsuccessful as a skin graft, but today it is successfully used as a dressing for the management of chronic wounds. The FPCL has, however, become an instrument for investigating cell-connective tissue interactions within a three-dimensional matrix. Through the capacity of cell compaction of collagen fibrils, the FPCL undergoes a reduction in volume referred to as lattice contraction. Lattice contraction proceeds by cell-generated forces that reduce the water mass between collagen fibers, generating a closer relationship between collagen fibers. The compaction of collagen fibers is responsible for the reduction in the FPCL volume. Cell-generated forces through the linkage of collagen fibers with fibroblast's cytoskeletal actin-rich microfilament structures are responsible for the completion of the collagen matrix compaction. The type of culture dish used to cast FPCL as well as the cell number will dictate the mechanism for compacting collagen matrices. Fibroblasts, at moderate density, cast as an FPCL within a petri dish and released from the surface of the dish soon after casting compact collagen fibers through cell tractional forces. Fibroblasts at moderate density cast as an FPCL within a tissue culture dish and not released for 4 days upon release show rapid lattice contraction through a mechanism of cell contraction forces. Fibroblasts at high density cast in an FPCL within a petri dish, released from the surface of the dish soon after casting, compact a collagen lattice very rapidly through forces related to cell elongation. The advantage of the FPCL contraction model is the study of cells in the three-dimensional environment, which is similar to the environment from which these cells were isolated. In this chapter methods are described for manufacturing collagen lattices, which assess the three forces involved in compacting and/or organizing collagen fibrils into thicker collagen fibers. The clinical relevance of the FPCL contraction model is related to advancing our understanding of wound contraction and scar contracture.

Melt electrospinning of poly(lactic acid) and polycaprolactone microfibers by using a hand-operated Wimshurst generator

NASA Astrophysics Data System (ADS)

Qin, Chong-Chong; Duan, Xiao-Peng; Wang, Le; Zhang, Li-Hua; Yu, Miao; Dong, Rui-Hua; Yan, Xu; He, Hong-Wei; Long, Yun-Ze

2015-10-01

A conventional melt electrospinning setup usually needs a large, heavy high-voltage power supply and cannot work without a plug (electricity supply). In this article, we report a new melt electrospinning setup based on a small hand-operated Wimshurst generator, which can avoid electrical interference between the high-voltage spinning system and the heating system, and make the setup very portable and safe. Poly(lactic acid) (PLA) and polycaprolactone (PCL) fibers with diameters of 15-45 μm were fabricated successfully by using this apparatus. Experimental parameters such as the rotational speed of the generator handle (a half turn to two turns per second) and the spinning distance (2-14 cm) were investigated. In addition, PLA and PCL fibers were directly melt-electrospun onto a pork liver, and the temperature and adhesiveness of the deposited fibers were studied. The results indicate that the apparatus and melt-electrospun polymer microfibers may be used in dressing for wound healing.A conventional melt electrospinning setup usually needs a large, heavy high-voltage power supply and cannot work without a plug (electricity supply). In this article, we report a new melt electrospinning setup based on a small hand-operated Wimshurst generator, which can avoid electrical interference between the high-voltage spinning system and the heating system, and make the setup very portable and safe. Poly(lactic acid) (PLA) and polycaprolactone (PCL) fibers with diameters of 15-45 μm were fabricated successfully by using this apparatus. Experimental parameters such as the rotational speed of the generator handle (a half turn to two turns per second) and the spinning distance (2-14 cm) were investigated. In addition, PLA and PCL fibers were directly melt-electrospun onto a pork liver, and the temperature and adhesiveness of the deposited fibers were studied. The results indicate that the apparatus and melt-electrospun polymer microfibers may be used in dressing for wound healing. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05367f

Clinical approach to wounds: débridement and wound bed preparation including the use of dressings and wound-healing adjuvants.

PubMed

Attinger, Christopher E; Janis, Jeffrey E; Steinberg, John; Schwartz, Jaime; Al-Attar, Ali; Couch, Kara

2006-06-01

This is a clinical review of current techniques in wound bed preparation found to be effective in assisting the wound-healing process. The process begins with the identification of a correct diagnosis of the wound's etiology and continues with optimizing the patient's medical condition, including blood flow to the wound site. Débridement as the basis of most wound-healing strategies is then emphasized. Various débridement techniques, including surgery, topical agents, and biosurgery, are thoroughly discussed and illustrated. Wound dressings, including the use of negative pressure wound therapy, are then reviewed. To properly determine the timing of advance therapeutic intervention, the wound-healing progress needs to be monitored carefully with weekly measurements. A reduction in wound area of 10 to 15 percent per week represents normal healing and does not mandate a change in the current wound-healing strategy. However, if this level of wound area reduction is not met consistently on a weekly basis, then alternative healing interventions should be considered. There is a growing body of evidence that can provide guidance on the appropriate use of such adjuvants in the problem wound. Several adjuvants are discussed, including growth factor, bioengineered tissues, and hyperbaric medicine.

Preparation of laser micropore porcine acellular dermal matrix for skin graft: an experimental study.

PubMed

Chai, Jia-Ke; Liang, Li-Ming; Yang, Hong-Ming; Feng, Rui; Yin, Hui-Nan; Li, Feng-Yu; Sheng, Zhi-Yong

2007-09-01

In our previous study, we used composite grafts consisting of meshed porcine acellular dermal matrix (PADM) and thin split-thickness autologous epidermis to cover full thickness burn wounds in clinical practice. However, a certain degree of contraction might occur because the distribution of dermal matrix was not uniform in burn wound. In this study, we prepare a composite skin graft consisting of PADM with the aid of laser to improve the quality of healing of burn wound. PADM was prepared by the trypsin/Triton X-100 method. Micropores were produced on the PADM with a laser punch. The distance between micropores varied from 0.8, 1.0, 1.2 to 1.5mm. Full thickness defect wounds were created on the back of 144 SD rats. The rats were randomly divided into six groups: micropore groups I-IV in which the wound were grafted with PADM with micropores, in four different distances, respectively and split-thickness autograft; mesh group rats received meshed PADM graft and split-thickness autograft; control group received simple split-thickness autografting. The status of wound healing was histologically observed at regular time points after surgery. The wound healing rate and contraction rate were calculated. The wound healing rate in micropore groups I and II was not statistically different from that in control group, but was significantly higher than that in mesh group 6 weeks after grafting. The wound healing rate in micropore groups III and IV was lower than that in mesh and control groups 4 and 6 weeks after grafting. The wound contraction rate in micropore groups I and II was remarkably lower than that in control group 4 and 6 weeks after surgery and it was significantly much lower than that in mesh group 6 weeks after surgery. Histological examination revealed good epithelization, regularly arranged collagenous fibers and integral structure of basement membrane. Laser micropore PADM (0.8 or 1.0mm in distance) grafting in combination with split-thickness autografting can improve wound healing. The PADM with laser micropores in 1.0mm distance is the better choice.

Comparison of the effects of the CO2 laser and chlorohexidine on the decontamination of infected cutaneous wounds: a histologic study in rats.

PubMed

Pinheiro, Antonio Luiz B; Cavalcanti Das Neves, Jérläcia; Lisboa De Castro, Jurema Freire; Lima Verde Santos, José Zilton; Da Fonseca Ribeiro De Sena, Kêsia Xisto; Brugnera, Aldo; Zanin, Fátima A; Matos De Oliveira, Marcos André

2002-06-01

The aim of this study was to compare histologically the effects of CO2 laser and chlorohexidine gluconate (4%) on Staphylococcus aureus-infected cutaneous wounds. Wound infection constitutes a big risk for patients, and it is usually associated with increased morbidity, mortality and hospital costs. It is accepted that local treatment of these infections is effective. Standardized wounds created on the dorsum of 36 rats were infected with Staphylococcus aureus and treated during 6 days as follows: group I, chlorohexidine gluconate (4%) applied to the wound surface during 1 min during 6 days; group II, single CO2 laser irradiation (8 W, CW, unfocused, 8-cm focal distance, 81,530 W/cm(2)), maintaining surface debris; group III, single CO2 laser irradiation (8 W, CW, unfocused, 8-cm focal distance, 81,530 W/cm(2)), removing the surface debris. Seven days after wounding, the animals were killed and specimens taken for light microscopy. On control wounds, epithelial ulceration and neutrophylic and lymphoplasmocitary inflammatory infiltrate was observed. On group II, there was epithelial hyperplasia, areas of ulceration and intense neutrophylic and lymphoplasmocitary inflammatory infiltrate. In group III, there was a neutrophylic inflammatory infiltrate underneath the surface debris and below that intense lymphoplasmocitary inflammatory infiltrate. When the surface debris was removed (group IV), there was epithelial ulceration and mild lymphoplasmocitary inflammatory infiltrate and fibroblasts and collagen fibers. The results of this study show that infected wounds treated with 4% chlorohexidine show a more pronounced inflammatory reaction when compared to that observed when the CO2 laser is used, especially when surface debris are removed; surface debris removal on laser-treated wounds results in better and more rapid healing; the surface debris may act as a culture medium for bacterial growth or, because of its characteristics, it may act as a local irritant and delay healing.

Evaluation of healing of infected cutaneous wounds treated with different energy densities

NASA Astrophysics Data System (ADS)

Santos, Nicole R. S.; Cangussú, Maria C. T.; N. dos Santos, Jean; Pinheiro, Antonio L. B.

2011-03-01

We aimed assess the effects of different energy densities of the association of red/IR laser light on the healing of cutaneous wounds infected Staphylococcus aureus. Background: Wound infection is the most common complication on healing wounds and cause both vascular and cellular responses on the tissue. Several therapeutics is used for improving wound healing including the use of different light sources, such as the Laser. Some energy densities present positive photobiological effects on the healing process. Material and Methods: 24 young adult male Wistar rats, under general anesthesia, had their dorsum shaven, cleaned and a 1 x 1cm cutaneous wound created with a scalpel and left without no suturing or dressings. The wounds were infected with Staphylococcus aureus and were randomly divided in 8 subgroups of 3 animals in each: Control, Group 10J/cm2, Group 20J/cm2, and Group 30J/cm2, 7 and 14 days each group. Laser phototherapy was carried out with a diode (λ680nm/790nm, P= 30mW/40mW, CW, Laser, Ø = 3mm, PD=424mW/cm2 and 566mW/cm2, t=11.8/ 8.8 sec, E=0.35J) and started immediately after surgery and repeated at every other day during 7 days. Laser light was applied on 4 points around wounded area. The animals were killed at either 8th or 15th day after contamination. Specimens were taken, routinely cut and processed to wax, stained and underwent histological analysis. The results were statistically analyzed. Results: Both 20 and 30J/cm2 caused intense collagen deposition at the end of the experimental time. But, when 20 J/cm2 was used the fibers were also well organized. Conclusion: Our results indicate that irradiated subjects showed improved wound healing being the 20 J/cm2 the energy the caused better histological response.

Three-dimensional printing of continuous-fiber composites by in-nozzle impregnation

PubMed Central

Matsuzaki, Ryosuke; Ueda, Masahito; Namiki, Masaki; Jeong, Tae-Kun; Asahara, Hirosuke; Horiguchi, Keisuke; Nakamura, Taishi; Todoroki, Akira; Hirano, Yoshiyasu

2016-01-01

We have developed a method for the three-dimensional (3D) printing of continuous fiber-reinforced thermoplastics based on fused-deposition modeling. The technique enables direct 3D fabrication without the use of molds and may become the standard next-generation composite fabrication methodology. A thermoplastic filament and continuous fibers were separately supplied to the 3D printer and the fibers were impregnated with the filament within the heated nozzle of the printer immediately before printing. Polylactic acid was used as the matrix while carbon fibers, or twisted yarns of natural jute fibers, were used as the reinforcements. The thermoplastics reinforced with unidirectional jute fibers were examples of plant-sourced composites; those reinforced with unidirectional carbon fiber showed mechanical properties superior to those of both the jute-reinforced and unreinforced thermoplastics. Continuous fiber reinforcement improved the tensile strength of the printed composites relative to the values shown by conventional 3D-printed polymer-based composites. PMID:26965201

Use of negative pressure wound therapy with instillation in the management of cervical necrotizing fasciitis.

PubMed

Frankel, Jonathan K; Rezaee, Rod P; Harvey, Donald J; McBeath, Evan R; Zender, Chad A; Lavertu, Pierre

2015-11-01

Cervical necrotizing fasciitis is an aggressive infection that can be rapidly fatal if aggressive therapies are not initiated early. Negative pressure wound therapy has been established as an effective tool in promoting wound healing, but its use in the acutely infected wound has been avoided because it limits frequent irrigations and standard dressing changes. We discuss a novel application of negative pressure wound therapy with instillation in an immunocompromised patient with extensive cervical necrotizing fasciitis. The negative pressure wound therapy with instillation provided pain relief by minimizing the frequency of dressing changes, increased the speed of healing, helped to control infection, and facilitated the development of a healthy wound bed sufficient for reconstruction with a split thickness skin graft. The role of negative pressure wound therapy with instillation continues to expand and can be used in the management of both acute and chronic wounds in the head and neck. © 2015 Wiley Periodicals, Inc.

The Effect of Oral Medication on Wound Healing.

PubMed

Levine, Jeffrey M

2017-03-01

The purpose of this learning activity is to provide information about the effects of oral medications on wound healing. This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. After participating in this educational activity, the participant should be better able to:1. Identify oral medications that aid in wound healing.2. Recognize oral medications that interfere with wound healing. Given the accelerated medical discoveries of recent decades, there is a surprising lack of oral medications that directly improve wound healing. Of the oral medications available, most target ancillary aspects of wound care such as pain management, infection mitigation, and nutrition. This article describes oral pharmacologic agents intended to build new tissue and aid in wound healing, as well as an introduction to oral medications that interfere with wound healing. This review will not discuss the pharmacology of pain management or treatment of infection, nor will it address nutritional supplements.

Interactions between Surfactants in Solution and Electrospun Protein Fibers: Effects on Release Behavior and Fiber Properties.

PubMed

Stephansen, Karen; García-Díaz, María; Jessen, Flemming; Chronakis, Ioannis S; Nielsen, Hanne M

2016-03-07

Intermolecular interaction phenomena occurring between endogenous compounds, such as proteins and bile salts, and electrospun compounds are so far unreported, despite the exposure of fibers to such biorelevant compounds when applied for biomedical purposes, e.g., tissue engineering, wound healing, and drug delivery. In the present study, we present a systematic investigation of how surfactants and proteins, as physiologically relevant components, interact with insulin-loaded fish sarcoplasmic protein (FSP) electrospun fibers (FSP-Ins fibers) in solution and thereby affect fiber properties such as accessible surface hydrophilicity, physical stability, and release characteristics of an encapsulated drug. Interactions between insulin-loaded protein fibers and five anionic surfactants (sodium taurocholate, sodium taurodeoxycholate, sodium glycocholate, sodium glycodeoxycholate, and sodium dodecyl sulfate), a cationic surfactant (benzalkonium chloride), and a neutral surfactant (Triton X-100) were studied. The anionic surfactants increased the insulin release in a concentration-dependent manner, whereas the neutral surfactant had no significant effect on the release. Interestingly, only minute amounts of insulin were released from the fibers when benzalkonium chloride was present. The FSP-Ins fibers appeared dense after incubation with this cationic surfactant, whereas high fiber porosity was observed after incubation with anionic or neutral surfactants. Contact angle measurements and staining with the hydrophobic dye 8-anilino-1-naphthalenesulfonic acid indicated that the FSP-Ins fibers were hydrophobic, and showed that the fiber surface properties were affected differently by the surfactants. Bovine serum albumin also affected insulin release in vitro, indicating that also proteins may affect the fiber performance in an in vivo setting.

Re-epithelialization resulted from prostate basal cells in canine prostatic urethra may represent the ideal healing method after two-micron laser resection of the prostate

PubMed Central

Cao, Ying; Luo, Guang-Heng; Luo, Lei; Yang, Xiu-Shu; Hu, Jian-Xin; Shi, Hua; Huang, Ping; Sun, Zhao-Lin; Xia, Shu-Jie

2015-01-01

The purpose of this study is to characterize the re-epithelialization of wound healing in canine prostatic urethra and to evaluate the effect of this re-epithelialization way after two-micron laser resection of the prostate (TmLRP). TmLRP and partial bladder neck mucosa were performed in 15 healthy adult male crossbred canines. Wound specimens were harvested at 3 days, and 1, 2, 3, and 4 weeks after operation, respectively. The histopathologic characteristics were observed by hematoxylin and eosin staining. The expression of cytokeratin 14 (CK14), CK5, CK18, synaptophysin (Syn), chromogranin A (CgA), uroplakin, transforming growth factor-β1(TGF-β1), and TGF-β type II receptor in prostatic urethra wound were examined by immunohistochemistry and real-time polymerase chain reaction, respectively. Van Gieson staining was performed to determine the expression of collagen fibers in prostatic urethra and bladder neck would. The results showed that the re-epithelialization of the prostatic urethra resulted from the mobilization of proliferating epithelial cells from residual prostate tissue under the wound. The proliferating cells expressed CK14, CK5, but not CK18, Syn, and CgA and re-epithelialize expressed uroplakin since 3 weeks. There were enhanced TGF-β1 and TGF-β type II receptor expression in proliferating cells and regenerated cells, which correlated with specific phases of re-epithelialization. Compared with the re-epithelialization of the bladder neck, re-epithelialization of canine prostatic urethra was faster, and the expression of collagen fibers was relatively low. In conclusion, re-epithelialization in canine prostatic urethra resulted from prostate basal cells after TmLRP and this re-epithelialization way may represent the ideal healing method from anatomic repair to functional recovery after injury. PMID:25652631

Development of sodium alginate/PVA antibacterial nanofibers by the incorporation of essential oils

NASA Astrophysics Data System (ADS)

Rafiq, M.; Hussain, T.; Abid, S.; Nazir, A.; Masood, R.

2018-03-01

Electrospinning is a well known method for the manufacturing of nanoscale fibers. Electrospun nanofibers have higher surface area to volume ratio and can be used for the incorporation of different materials. Essential oils are well known for their antimicrobial and healing properties since ancient times. The main objective of this study was to develop antibacterial nanofibers by the incorporation of essential oils in sodium alginate/PVA solution. Sodium alginate and PVA have excellent biocompatible properties which are the base of their use in wound care applications. Three different essential oils (cinnamon, clove, and lavender) at three different concentrations (0.5, 1 and 1.5%) were used to optimize the fiber forming conditions during electrospinning and then the desired antibacterial properties were evaluated. Addition of oils in PVA/SA solutions increased the viscosity but reduced the surface tension and conductivity as compared to pure PVA/sodium alginate solution. FTIR Spectra of composite fibers verified the successful incorporation of essential oils in nanofibers through electrospinning. All oil containing samples showed good antibacterial properties against staphylococcus aureus which make them a good replacement of antibiotics. Cinnamon oil loaded nanofibers showed the best results among selected oils regarding the antibacterial properties. Nanofibers with 1.5% cinnamon oil exhibited highest zone of inhabitation of 2.7 cm. Nanofibrous coated cotton gauze showed higher liquid absorptions as compared to simple cotton gauze and potential to be used as wound dressings for its improved liquid absorption and antibacterial activity.

Intraoral fiber-optic-based diagnostic for periodontal disease

NASA Astrophysics Data System (ADS)

Colston, Bill W., Jr.; Gutierrez, Dora M.; Everett, Matthew J.; Brown, Steve B.; Langry, Kevin C.; Cox, Weldon R.; Johnson, Paul W.; Roe, Jeffrey N.

2000-05-01

The purpose of this initial study was to begin development of a new, objective diagnostic instrument that will allow simultaneous quantitation of multiple proteases within a single periodontal pocket using a chemical fiber optic senor. This approach could potentially be adapted to use specific antibodies and chemiluminescence to detect and quantitate virtually any compound and compare concentrations of different compounds within the same periodontal pocket. The device could also be used to assay secretions in salivary ducts or from a variety of wounds. The applicability is, therefore, not solely limited to dentistry and the device would be important both for clinical diagnostics and as a research too.

Filament winding - Waking the sleeping giant

NASA Technical Reports Server (NTRS)

Freeman, W. T., Jr.; Stein, B. A.

1985-01-01

The use of filament winding (FW) in the production of aerospace composite structures is examined. The FW process applies spools of fiber and prepreg tow or prepreg tape to a male mandrel; the process is more efficient and cost effective than metallic construction. The fibers used in FW and the curing process are explained. The reduced storage and fabrication costs that result from FW are discussed. The use of FW to produce a filament-wound case for a solid rocket motor and the substructure and skin of an aircraft fuselage are described. Areas which require further development in order to expand the use of FW are listed and discussed.

Toughening of PMR composites by semi-interpenetrating networks

NASA Technical Reports Server (NTRS)

Tiwari, S. N.; Srinivansan, K.

1991-01-01

Polymerization of monomer reactants (PMR-15) type polyimide and RP46 prepregs were drum wound using IM-7 fibers. Prepregging and processing conditions were optimized to yield good quality laminates with fiber volume fractions of 60 percent (+/- 2 percent). Samples were fabricated and tested to determine comprehensive engineering properties of both systems. These included 0 deg flexure, short beam shear, transverse flexure and tension, 0 deg tension and compression, intralaminar shear, short block compression, mode 1 and 2 fracture toughness, and compression after impact properties. Semi-2-IPN (interpenetrating polymer networks) toughened PMR-15 and RP46 laminates were also fabricated and tested for the same properties.

Manufactured Textile Fibers

NASA Astrophysics Data System (ADS)

Gupta, Bhupender S.

The first conversion of naturally occurring fibers into threads strong enough to be looped into snares, knit to form nets, or woven into fabrics is lost in prehistory. Unlike stone weapons, such threads, cords, and fabrics—being organic in nature—have in most part disappeared, although in some dry caves traces remain. There is ample evidence to indicate that spindles used to assist in the twisting of fibers together had been developed long before the dawn of recorded history. In that spinning process, fibers such as wool were drawn out of a loose mass, perhaps held in a distaff, and made parallel by human fingers. (A maidservant so spins in Giotto's The Annunciation to Anne, ca. A.D. 1306, Arena Chapel, Padua, Italy.1) A rod (spindle), hooked to the lengthening thread, was rotated so that the fibers while so held were twisted together to form additional thread. The finished length then was wound by hand around the spindle, which, in becoming the core on which the finished product was accumulated, served the dual role of twisting and storing, and, in so doing, established a principle still in use today.

21 CFR 878.4011 - Tissue adhesive with adjunct wound closure device for topical approximation of skin.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY... approximated skin edges of wounds from surgical incisions, including punctures from minimally invasive surgery...

21 CFR 878.4011 - Tissue adhesive with adjunct wound closure device for topical approximation of skin.

Code of Federal Regulations, 2012 CFR

2012-04-01

... ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY... approximated skin edges of wounds from surgical incisions, including punctures from minimally invasive surgery...

21 CFR 878.4011 - Tissue adhesive with adjunct wound closure device for topical approximation of skin.

Code of Federal Regulations, 2013 CFR

2013-04-01

... ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY... approximated skin edges of wounds from surgical incisions, including punctures from minimally invasive surgery...

Effects of a specially pulsed electric field on an animal model of wound healing.

PubMed

Cinar, Kenan; Comlekci, Selcuk; Senol, Nurgul

2009-09-01

The possible beneficial effects of a specially pulsed electric field (PEF) on wound healing were investigated in this study. We made a pair of triangular, full-thickness, dorsal incisions in the skin of 32 healthy male mice (one control group and three exposure groups). The treatment groups were kept between parallel plates in a partially insulated exposed environment. Group I was exposed to an electric field intensity of 10 kV/m, group II was exposed to 1.9 kV/m, and group III was exposed to 0.9 kV/m. PEFs were applied to the subjects for 20-22 h and 8 consecutive days. We determined the differences in wound recovery between the groups based on the following parameters: collagen fiber density, inflammatory infiltration density, capillary proliferation, and existence of exudates. We found that a 0.9 kV/m-1.9 kV/m chopped direct current (DC) electric field with a 30 micros repetition time favorably affected collagen synthesis and wound recovery. Despite the intensity of 0.9-1.9 kV/m, PEF accelerated healing, but 10 kV/m decelerated this recovery process.

Process for making ceramic hot gas filter

DOEpatents

Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

2001-01-01

A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

Ceramic hot-gas filter

DOEpatents

Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

1999-01-01

A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

Ceramic hot-gas filter

DOEpatents

Connolly, E.S.; Forsythe, G.D.; Domanski, D.M.; Chambers, J.A.; Rajendran, G.P.

1999-05-11

A ceramic hot-gas candle filter is described having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during back pulse cleaning and is resistant to chemical degradation at high temperatures.

The Use of Biologic Scaffolds in the Treatment of Chronic Nonhealing Wounds

PubMed Central

Turner, Neill J.; Badylak, Stephen F.

2015-01-01

Significance: Injuries to the skin as a result of illness or injury, particularly chronic nonhealing wounds, present a major healthcare problem. Traditional wound care approaches attempt to control the underlying causes, such as infection and ischemia, while the application of wound dressings aims to modify a poorly healing wound environment into a microenvironment more closely resembling an acute wound allowing the body to heal the wound naturally. Recent Advances: Regenerative medicine approaches, such as the use of biologic scaffold materials comprising an intact extracellular matrix (ECM) or individual components of the ECM, are providing new therapeutic options that focus upon the provision of biochemical cues that alter the wound microenvironment to facilitate rapid restoration of normal skin architecture. Critical Issues: The incidence of chronic nonhealing wounds continues to increase. For example, between 15% and 20% of diabetics are likely to develop chronic, nonhealing foot wounds creating an increasing burden on healthcare systems worldwide. Future Directions: Developing a thorough understanding of wound microenvironment and the mechanisms by which biologic scaffolds work in vivo has the potential to markedly improve outcomes in the clinical translation for the treatment of chronic wounds. PMID:26244105

Peroxide-based oxygen generating topical wound dressing for enhancing healing of dermal wounds.

PubMed

Chandra, Prafulla K; Ross, Christina L; Smith, Leona C; Jeong, Seon S; Kim, Jaehyun; Yoo, James J; Harrison, Benjamin S

2015-01-01

Oxygen generating biomaterials represent a new trend in regenerative medicine that aims to generate and supply oxygen at the site of requirement, to support tissue healing and regeneration. To enhance the healing of dermal wounds, we have developed a highly portable, in situ oxygen generating wound dressings that uses sodium percarbonate (SPO) and calcium peroxide (CPO) as chemical oxygen sources. The dressing continuously generated oxygen for more than 3 days, after which it was replaced. In the in vivo testing on porcine full-thickness porcine wound model, the SPO/CPO dressing showed enhanced wound healing during the 8 week study period. Quantitative measurements of wound healing related parameters, such as wound closure, reepithelialization, epidermal thickness and collagen content of dermis showed that supplying oxygen topically using the SPO/CPO dressing significantly accelerated the wound healing. An increase in neovascularization, as determined using Von Willebrand factor (vWF) and CD31 staining, was also observed in the presence of SPO/CPO dressing. This novel design for a wound dressing that contains oxygen generating biomaterials (SPO/CPO) for supplying topical oxygen, may find utility in treating various types of acute to chronic wounds. © 2015 by the Wound Healing Society.

[Influence of different inner dressings in negative-pressure wound therapy on escharectomy wound of full-thickness burn rabbits].

PubMed

Lin, J H; Chen, J; Xue, D J; Huang, W X; Su, G L

2017-07-20

Objective: To explore the influence of different inner dressings in negative-pressure wound therapy (NPWT) on escharectomy wound of full-thickness burn rabbits. Methods: Eighteen Japanese white rabbits were inflicted with full-thickness burn on unilateral back. They were divided into polymer dressing group (PD), biological dressing group (BD), and silver biological dressing group (SBD), according to the random number table, with 6 rabbits in each group. On 3 days post burn, the wounds were performed with escharectomy, and then wounds of rabbits in group PD were covered with polyurethane foam. Wounds of rabbits in group BD were covered with porcine acellular dermal matrix (ADM) and wounds of rabbits in group SBD were covered with silver porcine ADM. Then continuous NPWT was performed on rabbits of the three groups for 7 days. Immediately after surgery and on post surgery day (PSD) 7, general observation of wound was conducted and tissue around the wound was harvested for determination of dry to wet weight ratio. The content of bacteria was counted and the content of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and IL-6 in wound was determined by enzyme-linked immunosorbent assay. Fibroblasts in wound were counted after Masson staining and number of microvessels was counted after CD31 antibody immunohistochemical staining. Data were processed with analysis of variance for repeated measurement, LSD- t test, paired samples t test, and Bonferroni correction. Results: (1) Immediately after surgery, there was no granulation tissue in basal wound of rabbits in the three groups, with rich blood supply and obvious edema. On PSD 7, much granulation tissue was found in basal wound of rabbits in the three groups, with no or mild edema and no obvious redness and swelling in wound edge. (2) There were no significant differences in dry to wet weight ratios of tissue around the wound among and within the three groups immediately after surgery and on PSD 7 (with F values respectively 0.70 and 0.09, t values from 0.17 to 0.52, P values above 0.05). (3) Immediately after surgery, the content of bacteria in wounds of rabbits in groups PD, BD, and SBD was respectively (603.0±146.0) ×10(4,) (573.0±63.0) ×10(4,) and (590.0±100.0)×10(4) colony-forming unit (CFU)/g, with no significant difference among them ( F =0.13, P >0.05). On PSD 7, the content of bacteria in wounds of rabbits in groups PD, BD, and SBD were respectively (5.4±0.8) ×10(4,) (4.6±0.9) ×10(4,) and (3.5±0.9)×10(4) CFU/g. Among them, the content of bacteria in wounds of rabbits in group SBD was lower than that in groups PD and BD, respectively (with t values respectively 3.78 and 2.29, P <0.05 or P <0.01). The content of bacteria in wounds of rabbits in the three groups on PSD 7 was decreased compared with that immediately after surgery (with t values from 10.05 to 21.81, P values below 0.01). (4) There was no significant difference in content of TNF-α, IL-1β, and IL-6 in wounds of rabbits in the three groups immediately after surgery and on PSD 7 (with F values from 0.10 to 1.89, P values above 0.05). The content of TNF-α in wounds of rabbits in the three groups on PSD 7 was significantly higher than that immediately after surgery (with t values from 2.93 to 5.01, P <0.05 or P <0.01). (5) There was no significant difference in amount of fibroblasts in wounds of rabbits in the three groups immediately after surgery and on PSD 7 (with F values respectively 0.01 and 0.81, P values above 0.05). The amount of fibroblasts in wounds of rabbits in the three groups on PSD 7 was larger than that immediately after surgery (with t values from 4.78 to 11.58, P values below 0.01). (6) There was no significant difference in number of microvessels in wounds of rabbits in the three groups immediately after surgery and on PSD 7 (with F values respectively 2.42 and 2.49, P values above 0.05). The number of microvessels in wounds of rabbits in the three groups on PSD 7 was larger than that immediately after surgery (with t values from 7.17 to 11.14, P values below 0.01). Conclusions: SBD is better at inhibiting the growth of bacteria. PD, BD, and SBD have almost the same effects on reducing tissue edema and inflammatory reaction, and on promoting the accumulation of collagen fibers and tissue vascularization.

Directional Cell Migration in Response to Repeated Substratum Stretching

NASA Astrophysics Data System (ADS)

Okimura, Chika; Iwadate, Yoshiaki

2017-10-01

Crawling migration plays an essential role in a variety of biological phenomena, including development, wound healing, and immune system function. Migration properties such as anterior-posterior polarity, directionality, and velocity are regulated not only by the reception of a chemoattractant but also by sensing mechanical inputs from the external environment. In this review, we describe the mechanical response of migrating cells, particularly under repeated stretching of the elastic substratum, highlighting the fact that there appear to be two independent mechanosensing systems that generate the polarity needed for migration. Cells that have no stress fibers, such as Dictyostelium cells and neutrophil-like differentiated HL-60 cells, migrate perpendicular to the stretching direction via myosin II localization. Cells that do possess stress fibers, however, such as fish keratocytes, migrate parallel to the stretching via a stress-fiber-dependent process.

The financial and quality-of-life cost to patients living with a chronic wound in the community.

PubMed

Kapp, Suzanne; Santamaria, Nick

2017-12-01

Chronic wounds are associated with financial and personal costs. The system level expense associated with chronic wounds has been established, however, the out-of-pocket cost incurred by individuals who self-fund has not been the focus of extensive investigation. Recently, there has been renewed interest in evaluating quality of life, in line with the shift to patient enablement and self-care in chronic disease management. The objectives of this research were to describe the out-of-pocket wound treatment costs and the quality of life of people who have chronic wounds. A questionnaire incorporating the Cardiff Wound Impact Schedule and purpose-designed instruments was completed by a non-probability, convenience sample of 113 people in Australia and Wales. Data was analysed using descriptive statistics. The sample was on average 63·6 years of age and had wounds that were on an average 109 weeks duration. Participants had spent on average AU$2475 on wound dressing products since the wound started, and AU$121·82 in the most recent 28 days which represented 10% of their disposable income. Health-related quality of life was sub-optimal, 6/10 (ave) according to the Cardiff Wound Impact Schedule. Younger participants reported significantly poorer quality of life on all CWIS sub-scales when compared to older participants. This study found that chronic wounds present a significant financial cost to individuals who must self-fund their wound dressings and other wound treatment related expenses. Participants who had access to wound product subsidisation also experienced personal financial costs. People who have chronic wounds experience sub-optimal quality of life therefore this condition is also costly to the individual's well-being. The quality of life of younger people has not received adequate attention and requires further consideration given the many years that younger people may have to live with this debilitating and often recurrent condition. Continued action is required to reduce the financial and personal costs experienced by people who have chronic wounds. It is imperative that healthcare funding is directed to people who have chronic wounds, in particular to alleviate the out-of-pocket costs experienced by self-funders. Continued attention to the quality of life of people who have chronic wounds is required to minimise the negative effects of this condition and enhance well-being. © 2017 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

A Novel Wound Retractor Combining Continuous Irrigation and Barrier Protection Reduces Incisional Contamination in Colorectal Surgery.

PubMed

Papaconstantinou, Harry T; Ricciardi, Rocco; Margolin, David A; Bergamaschi, Roberto; Moesinger, Robert C; Lichliter, Warren E; Birnbaum, Elisa H

2018-03-09

Surgical site infection (SSI) remains a persistent and morbid problem in colorectal surgery. Key to its pathogenesis is the degree of intraoperative bacterial contamination at the surgical site. The purpose of this study was to evaluate a novel wound retractor at reducing bacterial contamination. A prospective multicenter pilot study utilizing a novel wound retractor combining continuous irrigation and barrier protection was conducted in patients undergoing elective colorectal resections. Culture swabs were collected from the incision edge prior to device placement and from the exposed and protected incision edge prior to device removal. The primary and secondary endpoints were the rate of enteric and overall bacterial contamination on the exposed incision edge as compared to the protected incision edge, respectively. The safety endpoint was the absence of serious device-related adverse events. A total of 86 patients were eligible for analysis. The novel wound retractor was associated with a 66% reduction in overall bacterial contamination at the protected incision edge compared to the exposed incision edge (11.9 vs. 34.5%, P < 0.001), and 71% reduction in enteric bacterial contamination (9.5% vs. 33.3%, P < 0.001). The incisional SSI rate was 2.3% in the primary analysis and 1.2% in those that completed the protocol. There were no adverse events attributed to device use. A novel wound retractor combining continuous irrigation and barrier protection was associated with a significant reduction in bacterial contamination. Improved methods to counteract wound contamination represent a promising strategy for SSI prevention (NCT 02413879).

The acousto-ultrasonic approach

NASA Technical Reports Server (NTRS)

Vary, Alex

1987-01-01

The nature and underlying rationale of the acousto-ultrasonic approach is reviewed, needed advanced signal analysis and evaluation methods suggested, and application potentials discussed. Acousto-ultrasonics is an NDE technique combining aspects of acoustic emission methodology with ultrasonic simulation of stress waves. This approach uses analysis of simulated stress waves for detecting and mapping variations of mechanical properties. Unlike most NDE, acousto-ultrasonics is less concerned with flaw detection than with the assessment of the collective effects of various flaws and material anomalies. Acousto-ultrasonics has been applied chiefly to laminated and filament-wound fiber reinforced composites. It has been used to assess the significant strength and toughness reducing effects that can be wrought by combinations of essentially minor flaws and diffuse flaw populations. Acousto-ultrasonics assesses integrated defect states and the resultant variations in properties such as tensile, shear, and flexural strengths and fracture resistance. Matrix cure state, porosity, fiber orientation, fiber volume fraction, fiber-matrix bonding, and interlaminar bond quality are underlying factors.

AHNAK1 and AHNAK2 are costameric proteins: AHNAK1 affects transverse skeletal muscle fiber stiffness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marg, Andreas, E-mail: andreas.marg@mdc-berlin.de; Haase, Hannelore; Neumann, Tanja

2010-10-08

Research highlights: {yields} AHNAK1 and AHNAK2 are costameric proteins. {yields} Intact membrane repair in AHNAK1-deficient mice. {yields} AHNAK1{sup -/-} single fibers have a higher transverse stiffness. -- Abstract: The AHNAK scaffold PDZ-protein family is implicated in various cellular processes including membrane repair; however, AHNAK function and subcellular localization in skeletal muscle are unclear. We used specific AHNAK1 and AHNAK2 antibodies to analyzed the detailed localization of both proteins in mouse skeletal muscle. Co-localization of AHNAK1 and AHNAK2 with vinculin clearly demonstrates that both proteins are components of the costameric network. In contrast, no AHNAK expression was detected in the T-tubulemore » system. A laser wounding assay with AHNAK1-deficient fibers suggests that AHNAK1 is not involved in membrane repair. Using atomic force microscopy (AFM), we observed a significantly higher transverse stiffness of AHNAK1{sup -/-} fibers. These findings suggest novel functions of AHNAK proteins in skeletal muscle.« less

The role of footwear in the prevention of foot lesions in patients with NIDDM. Conventional wisdom or evidence-based practice?

PubMed

Litzelman, D K; Marriott, D J; Vinicor, F

1997-02-01

To conduct a prospective evaluation of footwear characteristics as predictors of diabetic foot wounds. A total of 352 patients with NIDDM enrolled in a randomized controlled trial aimed at preventing diabetic foot lesions in an academic general medicine practice were studied. Foot wounds (n = 63) were modeled univariately and multivariably using generalized estimating equations. The dependent variable was a wound classified as a 1.2 or greater according to the Seattle Wound Classification System, indicating at least a superficial or healing minor lesion with no functional interruption of the protective cutaneous barrier. Independent variables included detailed measures of style and material of patients' indoor and outdoor shoes, appropriate length and width, sock fibers, whether the patient had bought new shoes in the past 6 months, and if the patient had been recommended for special shoes. Modeling controlled for intervention status and physiological measures (baseline wound, monofilament abnormalities, and serum HDL level). Initial screening (P < 0.20) suggested that a recommendation for special shoes, shoe length, and shoe width were indicative of wounds at follow-up (odds ratios [ORs] 2.19, 1.84, 1.86, respectively), while having bought shoes in the past 6 months was associated with no wound at follow-up (OR 0.60). The final multivariable model included only the recommendation for special shoes (OR 2.19; 95% CI 1.07-4.49). Many variables commonly cited as protective measures in footwear for diabetic patients were not prospectively predictive when controlling for physiological risk factors. Rigorous analyses are needed to examine the many assumptions regarding footwear recommendations for diabetic patients.

Experimental research on continuous basalt fiber and basalt-fibers-reinforced polymers

NASA Astrophysics Data System (ADS)

Zhang, Xueyi; Zou, Guangping; Shen, Zhiqiang

2008-11-01

The interest for continuous basalt fibers and reinforced polymers has recently grown because of its low price and rich natural resource. Basalt fiber was one type of high performance inorganic fibers which were made from natural basalt by the method of melt extraction. This paper discusses basic mechanical properties of basalt fiber. The other work in this paper was to conduct tensile testing of continuous basalt fiber-reinforced polymer rod. Tensile strength and stress-strain curve were obtained in this testing. The strength of rod was fairly equal to rod of E-glass fibers and weaker than rod of carbon fibers. Surface of crack of rod was studied. An investigation of fracture mechanism between matrix and fiber was analyzed by SEM (Scanning electron microscopy) method. A poor adhesion between the matrix and fibers was also shown for composites analyzing SEM photos. The promising tensile properties of the presented basalt fibers composites have shown their great potential as alternative classical composites.

A MYB/ZML Complex Regulates Wound-Induced Lignin Genes in Maize.

PubMed

Vélez-Bermúdez, Isabel-Cristina; Salazar-Henao, Jorge E; Fornalé, Silvia; López-Vidriero, Irene; Franco-Zorrilla, José-Manuel; Grotewold, Erich; Gray, John; Solano, Roberto; Schmidt, Wolfgang; Pagés, Montserrat; Riera, Marta; Caparros-Ruiz, David

2015-11-01

Lignin is an essential polymer in vascular plants that plays key structural roles in vessels and fibers. Lignification is induced by external inputs such as wounding, but the molecular mechanisms that link this stress to lignification remain largely unknown. In this work, we provide evidence that three maize (Zea mays) lignin repressors, MYB11, MYB31, and MYB42, participate in wound-induced lignification by interacting with ZML2, a protein belonging to the TIFY family. We determined that the three R2R3-MYB factors and ZML2 bind in vivo to AC-rich and GAT(A/C) cis-elements, respectively, present in a set of lignin genes. In particular, we show that MYB11 and ZML2 bind simultaneously to the AC-rich and GAT(A/C) cis-elements present in the promoter of the caffeic acid O-methyl transferase (comt) gene. We show that, like the R2R3-MYB factors, ZML2 also acts as a transcriptional repressor. We found that upon wounding and methyl jasmonate treatments, MYB11 and ZML2 proteins are degraded and comt transcription is induced. Based on these results, we propose a molecular regulatory mechanism involving a MYB/ZML complex in which wound-induced lignification can be achieved by the derepression of a set of lignin genes. © 2015 American Society of Plant Biologists. All rights reserved.

Sutureless closure of scleral wounds in animal models by the use of laser welded biocompatible patches

NASA Astrophysics Data System (ADS)

Rossi, Francesca; Matteini, Paolo; Menabuoni, Luca; Lenzetti, Ivo; Pini, Roberto

2011-03-01

The common procedures used to seal the scleral or conjunctival injuries are based on the traditional suturing techniques, that may induce foreign body reaction during the follow up, with subsequent inflammation and distress for the patient. In this work we present an experimental study on the laser welding of biocompatible patches onto ocular tissues, for the closure of surgical or trauma wounds. The study was performed ex vivo in animal models (porcine eyes). A penetrating perforation of the ocular tissue was performed with a surgical knife. The wound walls were approximated, and a biocompatible patch was put onto the outer surface of the tissue, in order to completely cover the wound as a plaster. The patches were prepared with a biocompatible and biodegradable polymer, showing high mechanical strength, good elasticity, high permeability for vapour and gases and rather low biodegradation. During preparation, Indocyanine Green (ICG) was included in the biopolymeric matrix, so that the films presented high absorption at 810 nm. Effective adhesion of the membranes to the ocular tissues was obtained by using diode laser light emitted from an 810 nm diode laser and delivered by means of a 300 μm core diameter optical fiber, to produce spots of local film/tissue adhesion, due to the photothermal effect at the interface. The result is an immediate closure of the wound, thus reducing post-operative complications due to inflammation.

Defective Wound-healing in Aging Gingival Tissue.

PubMed

Cáceres, M; Oyarzun, A; Smith, P C

2014-07-01

Aging may negatively affect gingival wound-healing. However, little is known about the mechanisms underlying this phenomenon. The present study examined the cellular responses associated with gingival wound-healing in aging. Primary cultures of human gingival fibroblasts were obtained from healthy young and aged donors for the analysis of cell proliferation, cell invasion, myofibroblastic differentiation, and collagen gel remodeling. Serum from young and old rats was used to stimulate cell migration. Gingival repair was evaluated in Sprague-Dawley rats of different ages. Data were analyzed by the Mann-Whitney and Kruskal-Wallis tests, with a p value of .05. Fibroblasts from aged donors showed a significant decrease in cell proliferation, migration, Rac activation, and collagen remodeling when compared with young fibroblasts. Serum from young rats induced higher cell migration when compared with serum from old rats. After TGF-beta1 stimulation, both young and old fibroblasts demonstrated increased levels of alpha-SMA. However, alpha-SMA was incorporated into actin stress fibers in young but not in old fibroblasts. After 7 days of repair, a significant delay in gingival wound-healing was observed in old rats. The present study suggests that cell migration, myofibroblastic differentiation, collagen gel remodeling, and proliferation are decreased in aged fibroblasts. In addition, altered cell migration in wound-healing may be attributable not only to cellular defects but also to changes in serum factors associated with the senescence process. © International & American Associations for Dental Research.

HMGB1 Promotes Intraoral Palatal Wound Healing through RAGE-Dependent Mechanisms.

PubMed

Tancharoen, Salunya; Gando, Satoshi; Binita, Shrestha; Nagasato, Tomoka; Kikuchi, Kiyoshi; Nawa, Yuko; Dararat, Pornpen; Yamamoto, Mika; Narkpinit, Somphong; Maruyama, Ikuro

2016-11-23

High mobility group box 1 (HMGB1) is tightly connected to the process of tissue organization upon tissue injury. Here we show that HMGB1 controls epithelium and connective tissue regeneration both in vivo and in vitro during palatal wound healing. Heterozygous HMGB1 ( Hmgb1 +/- ) mice and Wild-type (WT) mice were subjected to palatal injury. Maxillary tissues were stained with Mallory Azan or immunostained with anti-HMGB1, anti-proliferating cell nuclear antigen (PCNA), anti-nuclear factor-κB (NF-κB) p50 and anti-vascular endothelial growth factor (VEGF) antibodies. Palatal gingival explants were cultured with recombinant HMGB1 (rHMGB1) co-treated with siRNA targeting receptor for advanced glycation end products (RAGEs) for cell migration and PCNA expression analysis. Measurement of the wound area showed differences between Hmgb1 +/- and WT mice on Day 3 after wounding. Mallory Azan staining showed densely packed of collagen fibers in WT mice, whereas in Hmgb1 +/- mice weave-like pattern of low density collagen bundles were present. At three and seven days post-surgery, PCNA, NF-κB p50 and VEGF positive keratinocytes of WT mice were greater than that of Hmgb1 +/- mice. Knockdown of RAGE prevents the effect of rHMGB1-induced cell migration and PCNA expression in gingival cell cultures. The data suggest that HMGB1/RAGE axis has crucial roles in palatal wound healing.

Arc spray fabrication of metal matrix composite monotape

NASA Technical Reports Server (NTRS)

Westfall, L. J. (Inventor)

1985-01-01

Arc metal spraying is used to spray liquid metal onto an array of high strength fibers that were previously wound onto a large drum contained inside a controlled atmosphere chamber. This chamber is first evacuated to remove gaseous contaminants and then backfilled with a neutral gas up to atmospheric pressure. This process is used to produce a large size metal matrix composite monotape.

ECM Proteins Glycosylation and Relation to Diabetes

NASA Astrophysics Data System (ADS)

Pernodet, Nadine; Bloomberg, Ayla; Sood, Vandana; Slutsky, Lenny; Ge, Shouren; Clark, Richard; Rafailovich, Miriam

2004-03-01

The chemical modification and crosslinking of proteins by sugar glycosylation contribute to the aging of tissue proteins, and acceleration of this reaction during hyperglycemia is implicated in the pathogenesis of diabetic complications, such as disorder of the wound healing. Advanced glycation endproducts (AGEs) formation and protein crosslinking are irreversible processes that alter the structural and functional properties of proteins, lipid components and nucleic acids. And the mechanism, by which it happens, is not clear. Fibrinogen and fibronectin are plasma proteins, which play a major role in human wound healing. Fibrinogen converts to an insoluble fibrin "gel" following a cut, which eventually forms a clot to prevent blood loss, to direct cell adhesion and migration for forming scars. Fibronectin is a critical protein for cell adhesion and migration in wound healing. The effects of glucose on the binding of these plasma proteins from the extra cellular matrix (ECM) were followed at different concentrations by atomic force microscopy and lateral force modulation to measure the mechanical response of the samples. Glucose solutions (1, 2, and 3mg/mL) were incubated with the protein (100 mg/ml) and silicon (Si) substrates spun with sulfonated polystyrene (SPS) 28% for five days. Data showed that not only the organization of the protein on the surface was affected but also its mechanical properties. At 3 mg/mL glucose, Fn fibers were observed to be harder than those of the control, in good agreement with our hypothesis that glycosylation hardens tissues by crosslinking of proteins in the ECM and might cause fibers to break more easily.

Estimation of limit strains in disk-type flywheels made of a compliant elastomeric matrix composite undergoing radial creep

NASA Astrophysics Data System (ADS)

Portnov, G. G.; Bakis, Ch. E.

2000-01-01

Fiber reinforced elastomeric matrix composites (EMCs) offer several potential advantages for construction of rotors for flywheel energy storage systems. One potential advantage, for safety considerations, is the existence of maximum stresses near the outside radius of thick circumferentially wound EMC disks, which could lead to a desirable self-arresting failure mode at ultimate speeds. Certain unidirectionally reinforced EMCs, however, have been noted to creep readily under the influence of stress transverse to the fibers. In this paper, stress redistribution in a spinning thick disk made of a circumferentially filament wound EMC material on a small rigid hub has been analyzed with the assumption of total radial stress relaxation due to radial creep. It is shown that, following complete relaxation, the circumferential strains and stresses are maximized at the outside radius of the disk. Importantly, the radial tensile strains are three times greater than the circumferential strains at any given radius. Therefore, a unidirectional EMC material system that can safely endure transverse tensile creep strains of at least three times the elastic longitudinal strain capacity of the same material is likely to maintain the theoretically safe failure mode despite complete radial stress relaxation.

Does preoperative electrical stimulation of the skin alter the healing process?

PubMed

Borba, Graziela C; Hochman, Bernardo; Liebano, Richard E; Enokihara, Milvia M S S; Ferreira, Lydia M

2011-04-01

In vitro studies have demonstrated that electrical current may affect fibroblast proliferation and synthesis of collagen fibers. In humans, the application of electrical current by positioning the positive electrode on skin wounds resulted in thinner hypertrophic scars. The aim of this study was to evaluate the effects of preoperative electrical stimulation on cutaneous wound healing in rats. Forty rats were divided into two groups of 20 animals each. In the control group, an incision was made on the back of the animals. In the stimulation group, a preoperative electrical stimulation was applied using a rectangular pulse current at a frequency of 7.7 Hz, and intensity of 8 mA, for 30 min, with the positive electrode placed on the back of the animal, and the negative electrode placed on the abdominal wall. Following, an incision was made on their back. Biopsy was carried out on postoperative day 7 and 14, and histologic analysis was performed. The number of newly formed vessels, fibroblasts, and type III collagen fibers in the stimulation group on postoperative day 7 were greater than those in the control group. Preoperative positive-polarity electrical stimulation positively affects angiogenesis and fibroblast proliferation. Copyright © 2011 Elsevier Inc. All rights reserved.

Barbed suture material technique for wound closure and concomitant tube placement in uniportal VATS for pneumothorax

PubMed Central

2017-01-01

Background Uniportal video-assisted thoracoscopic surgery (VATS) is an alternative modality for treatment of primary spontaneous pneumothorax (PSP) with its less invasiveness and acceptable surgical outcomes. However, a few reports have been introduced for wound management to achieve better cosmetic wound healing and for placement of the chest tube in uniportal VATS. Thus, we aimed to evaluate the feasibility of our novel method for wound closure and concomitant tube placement using continuous barbed suture material in uniportal VATS for PSP. Methods Between July 2012 and December 2015, consecutive 31 patients (22 males) underwent uniportal VATS to treat PSP. Bilateral approaches were performed in four patients, thus total 35 cases were enrolled. We divided them into two groups with one group of 17 (48.5%) cases (group A), using barbed absorbable wound closure device for knotless continuous wound closure and subsequent chest tube anchoring, and the other group of 18 (51.4%) cases (group B), using conventional suture anchoring after skin closure using absorbable suture device. Postoperative surgical outcomes were compared to assess the feasibility of this technique. Results Demographic data demonstrate no significant difference in both groups. There was no significant difference in length of hospital stay (3.7±1.2 vs. 4.1±1.2 days, P=0.267) and in median chest tube indwelling time (2.4±0.9 vs. 3.1±1.2 days, P=0.066), respectively. Operation time in group A was shorter than in group B but there was no significant difference (41.7±11.8 vs. 45.6±16.0 minutes, P=0.415). There was neither conversion to two or three port VATS in all cases. In group A, all chest tubes were removed with concomitant sealing the tube removal site by pulling the thread. Residual knots do not exist that stitch out procedure is not required. There was no wound complication in both groups during the median follow-up period of 18 months. Conclusions Knotless, barbed suture material technique for continuous wound closure with concomitant chest tube placement achieved equivocal outcomes in comparison to the conventional suture anchoring method. We suggest this simple technique for wound closure and easy tube removal with cosmetic wound healing in uniportal VATS for PSP. PMID:28616277

Burn depth determination using high-speed polarization-sensitive Mueller optical coherence tomography with continuous polarization modulation

NASA Astrophysics Data System (ADS)

Todorović, Miloš; Ai, Jun; Pereda Cubian, David; Stoica, George; Wang, Lihong

2006-02-01

National Health Interview Survey (NHIS) estimates more than 1.1 million burn injuries per year in the United States, with nearly 15,000 fatalities from wounds and related complications. An imaging modality capable of evaluating burn depths non-invasively is the polarization-sensitive optical coherence tomography. We report on the use of a high-speed, fiber-based Mueller-matrix OCT system with continuous source-polarization modulation for burn depth evaluation. The new system is capable of imaging at near video-quality frame rates (8 frames per second) with resolution of 10 μm in biological tissue (index of refraction: 1.4) and sensitivity of 78 dB. The sample arm optics is integrated in a hand-held probe simplifying the in vivo experiments. The applicability of the system for burn depth determination is demonstrated using biological samples of porcine tendon and porcine skin. The results show an improved imaging depth (1 mm in tendon) and a clear localization of the thermally damaged region. The burnt area determined from OCT images compares well with the histology, thus proving the system's potential for burn depth determination.

Bi-directional ultrasonic wave coupling to FBGs in continuously bonded optical fiber sensing.

PubMed

Wee, Junghyun; Hackney, Drew; Bradford, Philip; Peters, Kara

2017-09-01

Fiber Bragg grating (FBG) sensors are typically spot-bonded onto the surface of a structure to detect ultrasonic waves in laboratory demonstrations. However, to protect the rest of the optical fiber from any environmental damage during real applications, bonding the entire length of fiber, called continuous bonding, is commonly done. In this paper, we investigate the impact of continuously bonding FBGs on the measured Lamb wave signal. In theory, the ultrasonic wave signal can bi-directionally transfer between the optical fiber and the plate at any adhered location, which could potentially produce output signal distortion for the continuous bonding case. Therefore, an experiment is performed to investigate the plate-to-fiber and fiber-to-plate signal transfer, from which the signal coupling coefficient of each case is theoretically estimated based on the experimental data. We demonstrate that the two coupling coefficients are comparable, with the plate-to-fiber case approximately 19% larger than the fiber-to-plate case. Finally, the signal waveform and arrival time of the output FBG responses are compared between the continuous and spot bonding cases. The results indicate that the resulting Lamb wave signal output is only that directly detected at the FBG location; however, a slight difference in signal waveform is observed between the two bonding configurations. This paper demonstrates the practicality of using continuously bonded FBGs for ultrasonic wave detection in structural health monitoring (SHM) applications.

Multifunctional Flexible Composites Based on Continuous Carbon Nanotube Fiber

DTIC Science & Technology

2014-07-28

fibers [1] The mechanical and electrical behavior of carbon nanotube fibers spun continuously from an aerogel is discussed. These fibers exhibit moderate...loading, demonstrates their potential for sensing applications in advanced composite materials. Insight into the failure behavior of the aerogel -spun...nanotube fibers is reported-the aerogel -spun fibers are observed to undergo mild to severe kinking due to tensile failure. This kinking is attributed to

Protein-calorie malnutrition and involuntary weight loss: the role of aggressive nutritional intervention in wound healing.

PubMed

Himes, D

1999-03-01

Protein-calorie malnutrition and involuntary weight loss continue to be prevalent among hospitalized and long-term care patients, particularly the elderly. Studies on nutritional intervention have established a correlation between nutritional status, body weight, and rate of wound healing. Nutritional intervention, however, must be provided early enough to prevent a catabolic-induced decline in lean muscle mass, which can further impair wound healing. Chronic, nonhealing wounds are particularly difficult to treat and contribute to significant morbidity, mortality, and hospitalizations. More aggressive nutritional management and a greater understanding of the role of nutrition and weight gain in wound healing can result in more effective patient care. This article discusses the role of protein-calorie malnutrition and involuntary weight loss in hindering the wound-healing process, and the need to establish an optimal anabolic environment for weight gain and improved wound healing.

Honey-based dressings and wound care: an option for care in the United States.

PubMed

Pieper, Barbara

2009-01-01

Honey-based wound dressings have been used worldwide since ancient times. A honey product received US Federal Drug Administration approval in 2007, making this dressing an option for wound care. Honey has been found to exert anti-inflammatory and antibacterial effects without antibiotic resistance, promote moist wound healing, and facilitate debridement. However, it may cause a stinging pain. As is true of any wound dressing, its use must be carefully selected and monitored. Continued research is needed to add to its evidence base. This article provides a summary of the current evidence base for the use of honey and a review of its therapeutic effects and discusses implications for WOC nursing practice.

Physico-chemical properties and efficacy of silk fibroin fabric coated with different waxes as wound dressing.

PubMed

Kanokpanont, Sorada; Damrongsakkul, Siriporn; Ratanavaraporn, Juthamas; Aramwit, Pornanong

2013-04-01

Silk fibroin (SF) has been widely used as a wound dressing material due to its suitable physical and biological characteristics. In this study, a non-adhesive wound dressing which applies to cover the wound surface as an absorbent pad that would absorb wound fluid while accelerate wound healing was developed. The modification of SF fabrics by wax coating was purposed to prepare the non-adhesive wound dressing that is required in order to minimize pain and risk of repeated injury. SF woven fabrics were coated with different types of waxes including shellac wax, beeswax, or carnauba wax. Physical and mechanical properties of the wax-coated SF fabrics were characterized. It was clearly observed that all waxes could be successfully coated on the SF fabrics, possibly due to the hydrophobic interactions between hydrophobic domains of SF and waxes. The wax coating improved tensile modulus and percentage of elongation of the SF fabrics due to the denser structure and the thicker fibers coated. The in vitro degradation study demonstrated that all wax-coated SF fabrics remained up to 90% of their original weights after 7 weeks of incubation in lysozyme solution under physiological conditions. The wax coating did not affect the degradation behavior of the SF fabrics. A peel test of the wax-coated SF fabrics was carried out in the partial- and full-thickness wounds of porcine skin in comparison to that of the commercial wound dressing. Any wax-coated SF fabrics were less adhesive than the control, as confirmed by less number of cells attached and less adhesive force. This might be that the wax-coated SF fabrics showed the hydrophobic property, allowing the loosely adherence to the hydrophilic wound surface. In addition, the in vivo biocompatibility test of the wax-coated SF fabrics was performed in Sprague-Dawley rats with subcutaneous model. The irritation scores indicated that the carnauba wax-coated SF fabric was not irritant while the shellac wax or beeswax-coated SF fabrics were slightly irritant, comparing with the commercial wound dressing. Therefore, SF fabrics coated with waxes, particularly carnauba wax, would be promising choices of non-adhesive wound dressing. Copyright © 2013 Elsevier B.V. All rights reserved.

Continuous method of producing silicon carbide fibers

NASA Technical Reports Server (NTRS)

Barnard, Thomas Duncan (Inventor); Nguyen, Kimmai Thi (Inventor); Rabe, James Alan (Inventor)

1999-01-01

This invention pertains to a method for production of polycrystalline ceramic fibers from silicon oxycarbide (SiCO) ceramic fibers wherein the method comprises heating an amorphous ceramic fiber containing silicon and carbon in an inert environment comprising a boron oxide and carbon monoxide at a temperature sufficient to convert the amorphous ceramic fiber to a polycrystalline ceramic fiber. By having carbon monoxide present during the heating of the ceramic fiber, it is possible to achieve higher production rates on a continuous process.

A brief overview of compartmental modeling for intake of plutonium via wounds

DOE PAGES

Poudel, Deepesh; Klumpp, John Allan; Waters, Tom L.; ...

2017-06-07

Here, the aim of this study is to present several approaches that have been used to model the behavior of radioactive materials (specifically Pu) in contaminated wounds. We also review some attempts by the health physics community to validate and revise the National Council on Radiation Protection and Measurements (NCRP) 156 biokinetic model for wounds, and present some general recommendations based on the review. Modeling of intake via the wound pathway is complicated because of a large array of wound characteristics (e.g. solubility and chemistry of the material, type and depth of the tissue injury, anatomical location of injury). Moreover,more » because a majority of the documented wound cases in humans are medically treated (excised or treated with chelation), the data to develop biokinetic models for unperturbed wound exposures are limited. Since the NCRP wound model was largely developed from animal data, it is important to continue to validate and improve the model using human data whenever plausible.« less

Demonstrating a Conceptual Framework to Provide Efficient Wound Management Service for a Wound Care Center in a Tertiary Hospital.

PubMed

Chen, Yu-Tsung; Chang, Chang-Cheng; Shen, Jen-Hsiang; Lin, Wei-Nung; Chen, Mei-Yen

2015-11-01

Although the benefits of wound care services and multidisciplinary team care have been well elaborated on in the literature, there is a gap in the actual practice of wound care and the establishment of an efficient referral system. The conceptual framework for establishing efficient wound management services requires elucidation.A wound care center was established in a tertiary hospital in 2010, staffed by an integrated multidisciplinary team including plastic surgeons, a full-time coordinator, a physical therapist, occupational therapists, and other physician specialists. Referral patients were efficiently managed following a conceptual framework for wound care. This efficient wound management service consists of 3 steps: patient entry and onsite immediate wound debridement, wound re-evaluation, and individual wound bed preparation plan. Wound conditions were documented annually over 4 consecutive years.From January 2011 to December 2014, 1103 patients were recruited from outpatient clinics or inpatient consultations for the 3-step wound management service. Of these, 62% of patients achieved healing or improvement in wounds, 13% of patients experienced no change, and 25% of patients failed to follow-up. The outcome of wound treatment varied by wound type. Sixty-nine percent of diabetic foot ulcer patients were significantly healed or improved. In contrast, pressure ulcers were the most poorly healed wound type, with only 55% of patients achieving significantly healed or improved wounds.The 3-step wound management service in the wound care center efficiently provided onsite screening, timely debridement, and multidisciplinary team care. Patients could schedule appointments instead of waiting indefinitely for care. Further wound condition follow-up, education, and prevention were also continually provided.

Ciliary neurotrophic factor promotes the activation of corneal epithelial stem/progenitor cells and accelerates corneal epithelial wound healing.

PubMed

Zhou, Qingjun; Chen, Peng; Di, Guohu; Zhang, Yangyang; Wang, Yao; Qi, Xia; Duan, Haoyun; Xie, Lixin

2015-05-01

Ciliary neurotrophic factor (CNTF), a well-known neuroprotective cytokine, has been found to play an important role in neurogenesis and functional regulations of neural stem cells. As one of the most innervated tissue, however, the role of CNTF in cornea epithelium remains unclear. This study was to explore the roles and mechanisms of CNTF in the activation of corneal epithelial stem/progenitor cells and wound healing of both normal and diabetic mouse corneal epithelium. In mice subjecting to mechanical removal of corneal epithelium, the corneal epithelial stem/progenitor cell activation and wound healing were promoted by exogenous CNTF application, while delayed by CNTF neutralizing antibody. In cultured corneal epithelial stem/progenitor cells, CNTF enhanced the colony-forming efficiency, stimulated the mitogenic proliferation, and upregulated the expression levels of corneal epithelial stem/progenitor cell-associated transcription factors. Furthermore, the promotion of CNTF on the corneal epithelial stem/progenitor cell activation and wound healing was mediated by the activation of STAT3. Moreover, in diabetic mice, the content of CNTF in corneal epithelium decreased significantly when compared with that of normal mice, and the supplement of CNTF promoted the diabetic corneal epithelial wound healing, accompanied with the advanced activation of corneal epithelial stem/progenitor cells and the regeneration of corneal nerve fibers. Thus, the capability of expanding corneal epithelial stem/progenitor cells and promoting corneal epithelial wound healing and nerve regeneration indicates the potential application of CNTF in ameliorating limbal stem cell deficiency and treating diabetic keratopathy. © 2014 AlphaMed Press.

Longitudinal Evaluation of Wound Healing after Penetrating Corneal Injury: Anterior Segment Optical Coherence Tomography Study.

PubMed

Zheng, Kang Keng; Cai, Jianhao; Rong, Shi Song; Peng, Kun; Xia, Honghe; Jin, Chuan; Lu, Xuehui; Liu, Xinyu; Chen, Haoyu; Jhanji, Vishal

2017-07-01

Ocular imaging can enhance our understanding of wound healing. We report anterior segment optical coherence tomography (ASOCT) findings in penetrating corneal injury. Serial ASOCT was performed after repair of penetrating corneal injury. Internal aberrations of wound edges were labeled as "steps" or "gaps" on ASOCT images. The wound type was characterized as: type 1: continuous inner wound edge or step height ≤ 80 µm; type 2: step height > 80 µm; type 3: gap between wound edges; and type 4: intraocular tissue adherent to wound. Surgical outcomes of different wound types were compared. 50 consecutive patients were included (6 females, 44 males; mean age 33 ± 12 years). The average size of wound was 4.2 ± 2.6 mm (type 1, 8 eyes; type 2, 27 eyes; type 3, 12 eyes; type 4, 3 eyes). At the end of 3 months, 70% (n = 35) of the wounds were type 1. At the end of 6 months, all type 1 wounds had healed completely, whereas about half of type 2 (48.1%) and type 3 (50%) wounds had recovered to type 1 configuration. The wound type at baseline affected the height of step (p = 0.047) and corneal thickness at 6 months (p = 0.035). ASOCT is a useful tool for monitoring wound healing in cases with penetrating corneal injury. Majority of the wound edges appose between 3 and 6 months after trauma. In our study, baseline wound configuration affected the healing pattern.

Quercetin and low level laser therapy promote wound healing process in diabetic rats via structural reorganization and modulatory effects on inflammation and oxidative stress.

PubMed

Ahmed, Osama M; Mohamed, Tarek; Moustafa, Hala; Hamdy, Hany; Ahmed, Rasha R; Aboud, Ebtsam

2018-05-01

This study aimed to evaluate the effect of quercetin and the photo-stimulatory effect of low energy 632.8 nm laser irradiation on excisional wound healing in non-diabetic and diabetic rats. Streptozotocin (45 mg/kg body weight) was intraperitoneally applied for diabetes induction. A full-thickness skin wound (2 × 2 cm 2 ) was aseptically created with a scalpel in non-diabetic and diabetic rats on the shaved back of the animals. The wounded non-diabetic and diabetic rats were treated every other day with quercetin by oral gavage at dose 25 mg/kg body weight and/or with low level laser therapy (LLLT) for 14 days. The wound closure percent calculated during the course of the experiment at days 1, 7 and 14 was remarkably increased as a result of treatment of non-diabetic and diabetic wounded rats with quercetin and LLLT; the treatment with both was the most potent. The elevated blood glucose and the lowered serum insulin levels were significantly improved in diabetic wounded rats treated with quercetin and LLLT as compared to the diabetic wounded control. The histological findings indicated that the wounded skin showed a marked increase in collagen fibers which become well oriented in sub-epidermal tissue, intact epidermis and presence of hyperplasia covering well-developed granulation tissue in the wounded rats treated with quercetin and LLLT as compared to the corresponding wounded control. The elevated levels of serum pro-inflammatory cytokines, IL-1β and TNF-α, as well as PGE-2 and LTB-4 were decreased in non-diabetic and diabetic wounded rats with quercetin and LLLT while the lowered level of serum anti-inflammatory cytokine, IL-10, was increased. The augmented oxidative stress represented by increased serum lipid peroxides level was decreased and the serum level of non-enzymatic anti-oxidant glutathione was increased as a result of treatment with quercetin and LLLT. Thus, it can be suggested that the improvements in glycemic state, cytokines involved in inflammation and antioxidant defense system as well as structural reorganization after treatment with quercetin and LLLT may play pivotal roles in promoting the wound healing process. The study also concluded that the treatment with quercetin in association with LLLT was better in improving wound healing in non-diabetic and diabetic rats than the use of either of each. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Chitosan preparations for wounds and burns: antimicrobial and wound-healing effects

PubMed Central

Dai, Tianhong; Tanaka, Masamitsu; Huang, Ying-Ying; Hamblin, Michael R

2011-01-01

Since its discovery approximately 200 years ago, chitosan, as a cationic natural polymer, has been widely used as a topical dressing in wound management owing to its hemostatic, stimulation of healing, antimicrobial, nontoxic, biocompatible and biodegradable properties. This article covers the antimicrobial and wound-healing effects of chitosan, as well as its derivatives and complexes, and its use as a vehicle to deliver biopharmaceuticals, antimicrobials and growth factors into tissue. Studies covering applications of chitosan in wounds and burns can be classified into in vitro, animal and clinical studies. Chitosan preparations are classified into native chitosan, chitosan formulations, complexes and derivatives with other substances. Chitosan can be used to prevent or treat wound and burn infections not only because of its intrinsic antimicrobial properties, but also by virtue of its ability to deliver extrinsic antimicrobial agents to wounds and burns. It can also be used as a slow-release drug-delivery vehicle for growth factors to improve wound healing. The large number of publications in this area suggests that chitosan will continue to be an important agent in the management of wounds and burns. PMID:21810057

Diode Laser-Assisted Surgical Therapy for Early Treatment of Oral Mucocele in a Newborn Patient: Case Report and Procedures Checklist

PubMed Central

Vitale, Marina Consuelo; Croci, Giorgio Alberto; Paulli, Marco; Carbone, Lorenzo; Gandini, Paola

2018-01-01

Mucocele (also known as ranula or salivary gland mucous cyst) of the newborn is a lesion present on the intraoral cavity, with the potential to interfere with respiration and feeding. In the present report, a case of mucocele in a 4-month female patient has been described. As conventional surgery can be followed by several complications such as intraoperative bleeding, difficulties in wound healing, and maintenance of sterility during surgery, in the present case, the use of diode laser has been planned. A topic anesthesia with lidocaine gel was performed. A diode laser (810 nm wavelength, continuous wave mode, power output of 3 watt, and 0.4 mm diameter fiber optic) was set for excising the lesion. The tip was directed at an angle of 10 to 15°, moving around the base of the lesion with a circular motion. The procedure was completed in 3 minutes. The patient was visited with a follow-up of 2 weeks and 4 months after excision. The intraoral wound healed without complications, and no signs of infection or mass recurrence were noted. The histopathological examination confirmed the diagnosis of mucocele. On the basis of the results of the present case report, the use of diode laser can be easily performed also in a noncompliant newborn patient for successful excision of mucocele lesions, and checklist of clinical procedures has been described. PMID:29854481

[Continuous medical education of general practitioners/family doctors in chronic wound care].

PubMed

Sinozić, Tamara; Kovacević, Jadranka

2014-10-01

A number of healthcare professionals, specialists in different fields and with different levels of education, as well as non-healthcare professionals, are involved in the care of chronic wound patients, thus forming a multidisciplinary team that is not only responsible for the course and outcome of treatment, but also for the patient quality of life. Family doctor is also member of the team the task of which is to prevent, diagnose, monitor and anticipate complications and relapses, as well as complete recovery of chronic wound patients, with the overall care continuing even after the wound has healed, or is involved in palliative care. A family medicine practitioner with specialized education and their team of associates in the primary health care, along with material conditions and equipment improvement, can provide quality care for patients with peripheral cardiovascular diseases and chronic wounds, organized according to the holistic approach. It is essential that all professional associations of family medicine as well as professional associations of other specialties - fields that are involved in wound prevention and treatment - be included in developing the continuous medical education program. The benefits of modern information technology should be used to good advantage. The education should be adapted to the needs of family practitioners in terms of the form, place, time, volume, financial affordability and choice of topic. The interest shown in team education should be transformed into specialized programs in the creation of which it is essential to include both physicians and nurses and their respective professional associations. Special attention should be paid to education and training of young doctors/nurses, those with less work experience, those that have not yet been part of such education, those that lack experience in working with wound patients, those whose teams deal mostly with elderly patients, and also residents in family medicine and Nursing College students.

An integrated wound-care pathway, supported by telemedicine, and competent wound management-Essential in follow-up care of adults with diabetic foot ulcers.

PubMed

Smith-Strøm, Hilde; Iversen, Marjolein M; Graue, Marit; Skeie, Svein; Kirkevold, Marit

2016-10-01

Diabetic foot ulcers are a feared complication of diabetes. Care delivered via telemedicine is suggested to be a more integrated care pathway to manage diabetic foot ulcers than traditionally delivered healthcare. Our aim was to explore patients' experiences with telemedicine follow-up care as compared to traditional care. Interpretive description was used as an analysis strategy. Data were collected using individual semi-structured interviews in the context of a larger ongoing clustered randomized controlled trial. Twenty-four patients (13 in the intervention group; 11 in the control group), aged 38-88 years were purposively recruited from the RCT in order to obtain a diverse sample in terms of group composition (intervention vs. control), age, gender, marital status, setting, and comorbidities present. The control group received traditional care. Three themes emerged from the interpretive analysis: competence of healthcare professionals, continuity of care, and easy access. This was independed of types of follow-up that had limited impact on the patients' follow-up experiences. Competence of healthcare professionals and continuity of care were crucial, because they can either enhance or jeopardize wound care. If these two latter factors were absent, patients would lose confidence in the wound care process. If this happened, patients pointed out that the expert knowledge of a specialist clinic was essential to receive good care. When telemedicine functioned optimally, telemedicine was an advantage in the treatment, because the images quickly captured changes in the wound healing that immediately could be corrected. Easy access is important for patients, but the importance of accessibility appears to be primary when the other two factors were present. The best wound care pathway for patients with diabetes foot ulcers is depended on a combination of competence and professional skills in wound management, and continuity of care. If telemedicine is functioning as intended, it can be an important additional tool. Copyright © 2016. Published by Elsevier Ireland Ltd.

Optimized design and structural mechanics of a single-piece composite helicopter driveshaft

NASA Astrophysics Data System (ADS)

Henry, Todd C.

In rotorcraft driveline design, single-piece composite driveshafts have much potential for reducing driveline mass and complexity over multi-segmented metallic driveshafts. The singlepiece shaft concept is enabled by the relatively high fatigue strain capacity of fiber reinforced polymer composites over metals. Challenges for single-piece driveshaft design lie in addressing the self-heating behavior of the composite due to the material damping, as well as, whirling stability, torsional buckling stability, and composite strength. Increased composite temperature due to self-heating reduces the composite strength and is accounted for in this research. The laminate longitudinal stiffness ( Ex) and strength (Fx) are known to be heavily degraded by fiber undulation, however, both are not well understood in compression. The whirling stability (a function of longitudinal stiffness) and the composite strength are strongly influential in driveshaft optimization, and thus are investigated further through the testing of flat and filament wound composite specimens. The design of single-piece composite driveshafts, however, needs to consider many failure criteria, including hysteresis-induced overheating, whirl stability, torsional buckling stability, and material failure by overstress. The present investigation uses multi-objective optimization to investigate the design space which visually highlights design trades. Design variables included stacking sequence, number of laminas, and number of hanger bearings. The design goals were to minimize weight and maximize the lowest factor of safety by adaptively generating solutions to the multi-objective problem. Several design spaces were investigated by examining the effect of misalignment, ambient temperature, and constant power transmission on the optimized solution. Several materials of interest were modeled using experimentally determined elastic properties and novel temperature-dependent composite strength. Compared to the baseline multi-segmented metallic driveline, weight reductions of 43% and 48% were obtained for single-piece flexible and rigid matrix composite shafts. The rigid matrix weight reduction was slightly lower than that seen in the literature due to consideration of shaft misalignment. In filament wound composites, the existence of fiber undulation introduces unique challenges in the prediction of compressive modulus and strength using traditional laminated composite theories. In the current investigation, novel full field strain measurements of compressively loaded specimens were used to evaluate local strain distributions in the region of a 0-deg. undulated lamina in a [0n/90n] s laminate (n=2,4,6) and a 30-deg. undulated lamina in a [30n/-60n] s laminate (n=2,4). Unique to this research, specimens were fabricated with carbon fibers, various amplitudes of undulation, and matrix materials with three different moduli of elasticity. Full-field strains were measured on the free edge and across the width of the compressively loaded specimens using two-dimensional digital image correlation (DIC). The observed strains were highly influenced by the undulation geometry. The longitudinal modulus of a [0n/90n] s laminate was more sensitive to reinforcement undulation when the matrix was flexible rather than rigid. An undulation with an amplitude/length ratio of 0.1 (low for a filament wound cylinder) reduces the average longitudinal modulus of elasticity in the undulation region by approximately 43% and 3% in laminates with flexible and rigid matrices, respectively, relative to a similar material without undulation. Observations of strain on the free edge revealed that fiber undulation caused elevated out-of-plane shear (gamma xz) and through-thickness normal (epsilonzz) strains in regions eventually involved in the fiber microbuckling failure process. A new three dimensional method was derived for the homogenization of a heterogeneous composite laminate consisting of individual anisotropic lamina for which structural coupling (Bij) may occur due to in- and out-of-plane (undulation) fiber reinforcement orientation. Threedimensional elastic constants were calculated by considering a representative volume element taken from the heterogeneous laminate. Three-dimensional elastic constant predictions were validated through comparison with established methods, both two- and three- dimensional. When the new derived three dimensional theory was applied to experimental results, the modulus and strength predictions compared favorably. A series of [+/-theta/89/+/-theta] cylinders with multiple helical fiber angles, winding patterns, and matrix materials were fabricated and tested in compression. Digital image correlation was used for the first time to measure outside surface displacements and strains. Longitudinal and hoop direction strain fluctuations between the undulated and non-undulated regions were found to be of the order of 20-30% of the mean values throughout the cylinders. Qualitatively, these fluctuations can be related to non-classical elastic couplings (Bij) in the anti-symmetric regions of the filament winding pattern. Failure of the cylinder occurred by fiber microbuckling, which initiated near the crossing of circumferential and helical cross-over bands. Based on a statistical analysis of surface strains in the local fiber coordinate system, it was determined that longitudinal compressive and in-plane longitudinal shear strains at incipient microbuckling were two to four times greater than their respective global counterparts. These results indicate the magnitude of strain concentration existing in the cylinders immediately before final failure (possibly during local failure) and highlight the importance of longitudinal compressive (epsilon11) and in-plane longitudinal shear strains (gamma12) in the failure process. A novel local-global approach was used in predicting the longitudinal modulus and strength of filament wound cylinders. Several representative volume elements were chosen to represent the filament winding rhombus, and were used as a basis for homogenization. Strength predictions were augmented with empirical critical distance factors. The average Ex and nu xy prediction error for Conathane DPRN 30917 was 6.8 % and 21 % and the average error for EPON 862 was 9.7 % and 14 % respectively. The strength prediction error was approximately 7.7 % and 24 % for 30917 and EPON 862 with failure location typically at the circumferential undulation by mode sigma 6 (tau12). The failure mode prediction was consistent with experimental observations from filament wound cylinders and flat-undulated specimens of similar lamination arrangement. Additional comparison with previous Adiprene LF750 filament wound cylinder testing produced prediction error of 11.8 % and 8.9 % for longitudinal modulus and strength respectively. The average absolute value of the error, considering every material, for modulus, strength, and Poisson's ratio was 14 %. Application of critical distance factors to flat undulated specimens was deemed unadvisable due to considerably higher strain intensity at failure compared to filament wound cylinders.

Wound Dressing in Maxillofacial Trauma.

DTIC Science & Technology

1979-10-31

Three local anesthetics (procaine, benzocaine , and etidocaine), two antiseptics (iodine and cetylpyridinium chloride, CPC), an anti- inflammatory...Fiber mats with procaine delivered 9% in one hour and 41% in one day. Films released similarly, and powders faster. Benzocaine and etidocaine were...released more slowly. Benzocaine powder released 27% in one hour and 77% in one day, and etidocaine powder released 9% in one hour and 59% in one day

Development of a two-stage membrane-based wash-water reclamation subsystem

NASA Technical Reports Server (NTRS)

Mccray, S. B.

1988-01-01

A two-stage membrane-based subsystem was designed and constructed to enable the recycle of wash waters generated in space. The first stage is a fouling-resistant tube-side-feed hollow-fiber ultrafiltration module, and the second stage is a spiral-wound reverse-osmosis module. Throughout long-term tests, the subsystem consistently produced high-quality permeate, processing actual wash water to 95 percent recovery.

Effect of Tissucol on connective tissue matrix during wound healing: an immunohistochemical study in rat skin.

PubMed

Romanos, G E; Strub, J R

1998-03-05

Fibrin sealants are very useful in different surgical fields. Fixation of free gingival grafts, root coverage procedures, and other techniques increasing connective tissue attachment may be associated with the application of Tissucol in periodontology. The aim of this study was to evaluate the influence of the fibrin sealant in the extracellular matrix, as well as alterations of the connective tissue matrix during wound-healing processes. In the back dermis of 15 Net male rats, Tissucol was implanted after intraperitoneal anesthesia. The implant material was placed in subcutaneous pockets (2 cm in length) which were sutured with interproximal sutures (test and control pockets). At 4, 7, 14, 21, and 28 days after surgery, biopsies of the healed and surrounding tissues were taken, frozen in liquid nitrogen, and examined histologically and immunohistochemically with antibodies against collagen types I, III, IV, V, VI, and VII. The findings showed thick and thin collagen type I and III fibers, respectively, with different orientations localized around the implant material. An increased amount of blood vessels and capillaries (their basement membranes containing collagen type IV) was observed during wound healing which may be associated with the implantation of the sealant. Collagen type V fibers were localized from the first days to the 4th postoperative week and, without any inflammatory reaction (according to histologic staining), formed a fibrillar extracellular matrix with high collagenase resistance. Collagen type VI showed a microfibrillar pattern of distribution, and collagen type VII was localized in the dermo epidermo junction and very deep in the connective tissue in the form of anchoring fibers (only in the test group) during the 4 postoperative weeks of healing. The data showed that Tissucol is a biocompatible component which cannot produce any extensive inflammatory reaction in the matrix. New blood vessel formation, an epithelial-connective tissue interface with high stability, as well as matrix alterations with high resistance in the proteolytic enzymes (i.e., collagenases) can be induced in the connective tissue after use of a fibrin sealant. All of these characteristics may be of great importance in connective tissue healing in periodontal surgical procedures.

Effects of protein-coated nanofibers on conformation of gingival fibroblast spheroids: potential utility for connective tissues regeneration.

PubMed

Kaufman, Gili; Whitescarver, Ryan; Nunes, Laiz; Palmer, Xavier-Lewis; Skrtic, Drago; Tutak, Wojtek

2017-10-09

Deep wounds in the gingiva caused by trauma or surgery require a rapid and robust healing of connective tissues. We propose utilizing gas-brushed nanofibers coated with collagen and fibrin for that purpose. Our hypotheses are that protein-coated nanofibers will: (i) attract and mobilize cells in various spatial orientations, and (ii) regulate the expression levels of specific extracellular matrix (ECM)-associated proteins, determining the initial conformational nature of dense and soft connective tissues. Gingival fibroblast monolayers and 3D spheroids were cultured on ECM substrate and covered with gas-blown poly-(DL-lactide-co-glycolide) (PLGA) nanofibers (uncoated/coated with collagen and fibrin). Cell attraction and rearrangement was followed by F-actin staining and confocal microscopy. Thicknesses of the cell layers, developed within the nanofibers, were quantified by imageJ software. The expression of collagen1α1 chain (Col1α1), fibronectin, and metalloproteinase 2 (MMP2) encoding genes was determined by quantitative reverse transcription analysis. Collagen- and fibrin- coated nanofibers induced cell migration toward fibers and supported cellular growth within the scaffolds. Both proteins affected the spatial rearrangement of fibroblasts by favoring packed cell clusters or intermittent cell spreading. These cell arrangements resembled the structural characteristic of dense and soft connective tissues, respectively. Within 3 days of incubation, fibroblast spheroids interacted with the fibers and grew robustly by increasing their thickness compared to monolayers. While the ECM key components, such as fibronectin and MMP2 encoding genes, were expressed in both protein groups, Col1α1 was predominantly expressed in bundled fibroblasts grown on collagen fibers. This enhanced expression of collagen1 is typical for dense connective tissue. Based on results of this study, our gas-blown, collagen- and fibrin-coated PLGA nanofibers are viable candidates for engineering soft and dense connective tissues with the required structural characteristics and functions needed for wound healing applications. Rapid regeneration of these layers should enhance healing of open wounds in a harsh oral environment. © 2017 IOP Publishing Ltd.

High oxygen facilitates wound induction of suberin polyphenolics in kiwifruit.

PubMed

Wei, Xiaopeng; Mao, Linchun; Han, Xueyuan; Lu, Wenjing; Xie, Dandan; Ren, Xingchen; Zhao, Yuying

2018-04-01

Rapid wound healing would be critical for successful long-term storage of fruits and vegetables. However, there was no direct evidence for the requirement and efficiency of oxygen in the fruit wound-healing process. This study was conducted to investigate the role of oxygen in wound-induced suberization by analyzing melanin, suberin polyphenolics (SPPs) and related enzymes in half-cut kiwifruits exposed to 100%, 50%, 21% and 0% oxygen. By 3 days after wounding, the wound surface of kiwifruit in high (50 and 100%) oxygen appeared as a continuous layer of melanin and SPPs underneath, which effectively prevent excessive water vapor loss from the fruit halves. In contrast, melanin and SPPs deposition in the wound surface in 0% oxygen was significantly reduced, with high water vapor loss. Rapid decrease of soluble phenolic acids (caffeic, p-coumaric, ferulic acids) was coupled with the increase of bound ferulic acid (coniferyl diacetate) especially in high oxygen by 9 days after wounding. Meanwhile, high oxygen enhanced peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase activities. Oxygen is required for wound-induced melanin and SPPs formation, and high oxygen is effective in promoting wound suberization in postharvest kiwifruit. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Thermoplastic coating of carbon fibers

NASA Technical Reports Server (NTRS)

Edie, D. D.; Lickfield, G. C.; Drews, M. J.; Ellison, M. S.; Gantt, B. W.

1989-01-01

A process is being developed which evenly coats individual carbon fibers with thermoplastic polymers. In this novel, continuous coating process, the fiber tow bundle is first spread cover a series of convex rollers and then evenly coated with a fine powder of thermoplastic matrix polymer. Next, the fiber is heated internally by passing direct current through the powder coated fiber. The direct current is controlled to allow the carbon fiber temperature to slightly exceed the flow temperature of the matrix polymer. Analysis of the thermoplastic coated carbon fiber tows produced using this continuous process indicates that 30 to 70 vol pct fiber prepregs can be obtained.

Autonomous Laser-Powered Vehicle

NASA Technical Reports Server (NTRS)

Stone, William C. (Inventor); Hogan, Bartholomew P. (Inventor)

2017-01-01

An autonomous laser-powered vehicle designed to autonomously penetrate through ice caps of substantial (e.g., kilometers) thickness by melting a path ahead of the vehicle as it descends. A high powered laser beam is transmitted to the vehicle via an onboard bare fiber spooler. After the beam enters through the dispersion optics, the beam expands into a cavity. A radiation shield limits backscatter radiation from heating the optics. The expanded beam enters the heat exchanger and is reflected by a dispersion mirror. Forward-facing beveled circular grooves absorb the reflected radiant energy preventing the energy from being reflected back towards the optics. Microchannels along the inner circumference of the beam dump heat exchanger maximize heat transfer. Sufficient amount of fiber is wound on the fiber spooler to permit not only a descent but also to permit a sample return mission by inverting the vehicle and melting its way back to the surface.

Silicone modified resins for graphite fiber laminates

NASA Technical Reports Server (NTRS)

Frost, L. W.; Bower, G. M.

1979-01-01

The development of silicon modified resins for graphite fiber laminates which will prevent the dispersal of graphite fibers when the composites are burned is discussed. Eighty-five silicone modified resins were synthesized and evaluated including unsaturated polyesters, thermosetting methacrylates, epoxies, polyimides, and phenolics. Neat resins were judged in terms of Si content, homogeneity, hardness, Char formation, and thermal stability. Char formation was estimated by thermogravimetry to 1,000 C in air and in N2. Thermal stability was evaluated by isothermal weight loss measurements for 200 hrs in air at three temperatures. Four silicone modified epoxies were selected for evaluation in unidirectional filament wound graphite laminates. Neat samples of these resins had 1,000 C char residues of 25 to 50%. The highest flexural values measured for the laminates were a strength of 140 kpsi and a modulus of 10 Mpsi. The highest interlaminar shear strength was 5.3 kpsi.

Carbon nanotubes/carbon fiber hybrid material: a super support material for sludge biofilms.

PubMed

Liu, Qijie; Dai, Guangze; Bao, Yanling

2017-07-16

Carbon fiber (CF) is widely used as a sludge biofilm support material for wastewater treatment. Carbon nanotubes/carbon fiber (CNTs/CF) hybrid material was prepared by ultrasonically assisted electrophoretic deposition (EPD). CF supports (CF without handling, CF oxidized by nitric acid, CNTs/CF hybrid material) were evaluated by sludge immobilization tests, bacterial cell adsorption tests and Derjaguin -Landau -Verwey -Overbeek (DLVO) theory. We found that the CNTs/CF hybrid material has a high capacity for adsorbing activated sludge, nitrifying bacterial sludge and pure strains (Escherichia coli and Staphylococcus aureus). CNTs deposited on CF surface easily wound around the curved surface of bacterial cell which resulted in capturing more bacterial cells. DLVO theory indicated the lowest total interaction energy of CNTs/CF hybrid material, which resulted in the highest bacteria cell adsorption velocity. Experiments and DLVO theory results proved that CNTs/CF hybrid material is a super support material for sludge biofilms.

Effect of phase lag on cyclic durability of laminated composite

NASA Astrophysics Data System (ADS)

Andersons, Janis; Limonov, V.; Tamuzs, Vitants

1992-07-01

Theoretical and experimental results on fatigue of laminated fiber reinforced composites under out-of-phase, biaxial cyclic loading are presented. Experiments were carried out on tubular filament wound samples of epoxy matrix/organic (Kevlar type) fiber composites. Fatigue strength under two different loading modes, namely cyclic torsion combined with axial tension or compression, was investigated for phase lags psi = 0, pi/2, and pi. Durability was shown to decrease with increasing phase shift both for axial tension (R = 0.1) and compression (R = 10). A matrix failure criterion was proposed for a unidirectionally reinforced ply, and the ply discount method was modified to account for phase lag. Calculated S-N curves agree reasonably well with experimental data.

Intraoral fiber optic-based diagnostic for periodontal disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, P W; Gutierrez, D M; Everett, M J

2000-01-21

The purpose of this initial study was to begin development of a new, objective diagnostic instrument that will allow simultaneous quantitation of multiple proteases within a single periodontal pocket using a chemical fiber optic sensor. This approach could potentially be adapted to use specific antibodies and chemiluminescence to detect and quantitate virtually any compound and compare concentrations of different compounds within the same periodontal pocket. The device could also be used to assay secretions in salivary ducts or from a variety of wounds. The applicability is, therefore, not solely limited to dentistry and the device would be important both formore » clinical diagnostics and as a research tool.« less

ZBLAN Fiber Phase B Study

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Smith, Guy A.

1997-01-01

A Phase B feasibility study will be performed for the study of the effects of microgravity on the preform processing and fiber pulling of ZBLAN optical glass. Continuing from the positive results achieved in the fiber annealing experiments in 20 second intervals at 0.001 g on the KC-135 and the 5 minute experiments on the SPAR rocket, experiments will continue to work towards design of a fiber sting to initiate fiber pulling operations in space. Anticipated results include less homogeneous nucleation than ground-based annealed fibers. Infrared Fiber Systems and Galileo are the participating industrial investigators.

Automated eddy current analysis of materials

NASA Technical Reports Server (NTRS)

Workman, Gary L.

1991-01-01

The use of eddy current techniques for characterizing flaws in graphite-based filament-wound cylindrical structures is described. A major emphasis was also placed upon incorporating artificial intelligence techniques into the signal analysis portion of the inspection process. Developing an eddy current scanning system using a commercial robot for inspecting graphite structures (and others) was a goal in the overall concept and is essential for the final implementation for the expert systems interpretation. Manual scans, as performed in the preliminary work here, do not provide sufficiently reproducible eddy current signatures to be easily built into a real time expert system. The expert systems approach to eddy current signal analysis requires that a suitable knowledge base exist in which correct decisions as to the nature of a flaw can be performed. A robotic workcell using eddy current transducers for the inspection of carbon filament materials with improved sensitivity was developed. Improved coupling efficiencies achieved with the E-probes and horseshoe probes are exceptional for graphite fibers. The eddy current supervisory system and expert system was partially developed on a MacIvory system. Continued utilization of finite element models for predetermining eddy current signals was shown to be useful in this work, both for understanding how electromagnetic fields interact with graphite fibers, and also for use in determining how to develop the knowledge base. Sufficient data was taken to indicate that the E-probe and the horseshoe probe can be useful eddy current transducers for inspecting graphite fiber components. The lacking component at this time is a large enough probe to have sensitivity in both the far and near field of a thick graphite epoxy component.

Axioms Altered With Research

DTIC Science & Technology

2012-08-01

antimicrobials (eg, imipenem ) at the time of initial care to assist in the control of wound infection. To better understand the role of Acinetobacter in wound... imipenem ) were used during initial surgical care in Iraq and Af- ghanistan. Finally, continued re- search into the morbidity and mor- tality of

Study on parameters affecting the mechanical properties of dry fiber bundles during continuous composite manufacturing processes

NASA Astrophysics Data System (ADS)

Maier, A.; Schledjewski, R.

2016-07-01

For continuous manufacturing processes mechanical preloading of the fibers occurs during the delivery of the fibers from the spool creel to the actual manufacturing process step. Moreover preloading of the dry roving bundles might be mandatory, e.g. during winding, to be able to produce high quality components. On the one hand too high tensile loads within dry roving bundles might result in a catastrophic failure and on the other hand the part produced under too low pre-tension might have low quality and mechanical properties. In this work, load conditions influencing mechanical properties of dry glass fiber bundles during continuous composite manufacturing processes were analyzed. Load conditions, i.e. fiber delivery speed, necessary pre-tension and other effects of the delivery system during continuous fiber winding, were chosen in process typical ranges. First, the strain rate dependency under static tensile load conditions was investigated. Furthermore different free gauge lengths up to 1.2 m, interactions between fiber points of contact regarding influence of sizing as well as impregnation were tested and the effect of twisting on the mechanical behavior of dry glass fiber bundles during the fiber delivery was studied.

Optical system components for navigation grade fiber optic gyroscopes

NASA Astrophysics Data System (ADS)

Heimann, Marcus; Liesegang, Maximilian; Arndt-Staufenbiel, Norbert; Schröder, Henning; Lang, Klaus-Dieter

2013-10-01

Interferometric fiber optic gyroscopes belong to the class of inertial sensors. Due to their high accuracy they are used for absolute position and rotation measurement in manned/unmanned vehicles, e.g. submarines, ground vehicles, aircraft or satellites. The important system components are the light source, the electro optical phase modulator, the optical fiber coil and the photodetector. This paper is focused on approaches to realize a stable light source and fiber coil. Superluminescent diode and erbium doped fiber laser were studied to realize an accurate and stable light source. Therefor the influence of the polarization grade of the source and the effects due to back reflections to the source were studied. During operation thermal working conditions severely affect accuracy and stability of the optical fiber coil, which is the sensor element. Thermal gradients that are applied to the fiber coil have large negative effects on the achievable system accuracy of the optic gyroscope. Therefore a way of calculating and compensating the rotation rate error of a fiber coil due to thermal change is introduced. A simplified 3 dimensional FEM of a quadrupole wound fiber coil is used to determine the build-up of thermal fields in the polarization maintaining fiber due to outside heating sources. The rotation rate error due to these sources is then calculated and compared to measurement data. A simple regression model is used to compensate the rotation rate error with temperature measurement at the outside of the fiber coil. To realize a compact and robust optical package for some of the relevant optical system components an approach based on ion exchanged waveguides in thin glass was developed. This waveguides are used to realize 1x2 and 1x4 splitter with fiber coupling interface or direct photodiode coupling.

Generating and Reversing Chronic Wounds in Diabetic Mice by Manipulating Wound Redox Parameters

PubMed Central

Dhall, Sandeep; Do, Danh C.; Garcia, Monika; Kim, Jane; Mirebrahim, Seyed H.; Lyubovitsky, Julia; Lonardi, Stefano; Nothnagel, Eugene A.; Schiller, Neal; Martins-Green, Manuela

2014-01-01

By 2025, more than 500 M people worldwide will suffer from diabetes; 125 M will develop foot ulcer(s) and 20 M will undergo an amputation, creating a major health problem. Understanding how these wounds become chronic will provide insights to reverse chronicity. We hypothesized that oxidative stress (OS) in wounds is a critical component for generation of chronicity. We used the db/db mouse model of impaired healing and inhibited, at time of injury, two major antioxidant enzymes, catalase and glutathione peroxidase, creating high OS in the wounds. This was necessary and sufficient to trigger wounds to become chronic. The wounds initially contained a polymicrobial community that with time selected for specific biofilm-forming bacteria. To reverse chronicity we treated the wounds with the antioxidants α-tocopherol and N-acetylcysteine and found that OS was highly reduced, biofilms had increased sensitivity to antibiotics, and granulation tissue was formed with proper collagen deposition and remodeling. We show for the first time generation of chronic wounds in which biofilm develops spontaneously, illustrating importance of early and continued redox imbalance coupled with the presence of biofilm in development of wound chronicity. This model will help decipher additional mechanisms and potentially better diagnosis of chronicity and treatment of human chronic wounds. PMID:25587545

An analytical solution for the elastoplastic response of a continuous fiber composite under uniaxial loading

NASA Technical Reports Server (NTRS)

Lee, Jong-Won; Allen, David H.

1990-01-01

A continuous fiber composite is modelled by a two-element composite cylinder in order to predict the elastoplastic response of the composite under a monotonically increasing tensile loading parallel to fibers. The fibers and matrix are assumed to be elastic-perfectly plastic materials obeying Hill's and Tresca's yield criteria, respectively. Here, the composite behavior when the fibers yield prior to the matrix is investigated.

Healing of partial thickness porcine skin wounds in a liquid environment.

PubMed

Breuing, K; Eriksson, E; Liu, P; Miller, D R

1992-01-01

This study employs a liquid-tight vinyl chamber for the topical fluid-phase treatment of experimental wounds in pigs. Continuous treatment with normal saline significantly reduced the early progression of tissue destruction in partial thickness burns. Uncovered burns formed a deep layer of necrosis (0.49 +/- 0.004 mm, mean +/- SD) although burn wounds covered with empty chambers demonstrated less necrosis (0.14 +/- 0.01 mm), fluid-treated wounds formed no eschar, and little tissue necrosis could be detected (less than 0.005 mm). Topical treatment with hypertonic dextran increased water flux across burn wounds by 0.24 ml/cm2/24 hr (mean, n = 95) over saline-treated wounds during the first 5 days after wounding. When partial thickness burn and excisional wounds were immersed in isotonic saline until healed, the daily efflux of water, protein, electrolytes, and glucose across the wound surface declined during healing to baseline values found in controls (saline-covered unwounded skin). The declining protein permeability was used as a reproducible, noninvasive, endogenous marker for the return of epithelial barrier function. Saline-treated excisional wounds healed within 8.6 +/- 0.6 days (mean +/- SD, n = 27) and burn wounds within 12.1 +/- 1.4 days (mean +/- SD, n = 15). Healing of fluid-treated wounds occurred without tissue maceration and showed less inflammation and less scar formation than healing of air exposed wounds (no attempt was made to compare rates of healing between air- and fluid-exposed wounds). We consider the fluid-filled chamber a potentially very useful diagnostic, monitoring, and delivery system for wound-healing research and for human wound therapy.

EFFECTS OF LOW-FREQUENCY ULTRASOUND ON MICROCIRCULATION IN VENOUS LEG ULCERS

PubMed Central

Wollina, Uwe; Heinig, Birgit; Naumann, Gunther; Scheibe, Armin; Schmidt, Wolf-Dieter; Neugebauer, Reimund

2011-01-01

Background: Therapeutic low-frequency ultrasound (US) has been used for many years to improve wound healing in chronic wounds like venous leg ulcers. No human data are available for the possible effects of single US applications on microcirculation and their frequency-dependency. Aims: To investigated the role of therapeutic low-frequency US on microcirculation of venous leg ulcers in vivo. Patients and Methods: This is a pilot study on an inpatient basis. We use a newly developed low-frequency continuous-wave US-equipment composed of a US transducer based on piezo-fiber composites that allow the change of frequency. In this study, we apply US of 34 kHz, 53.5 kHz, and 75 kHz respectively. Twelve patients with chronic venous leg ulcers are analyzed. As an adjunct to good ulcer care, therapeutic US is applied, non-contacting, once a day, in a subaqual position for 10 minutes. Microcirculation is assessed in the ulcers adjacent to skin before US-therapy, immediately after the treatment and 30 minutes later. We use a micro-light guide spectrophotometer (O2C, LEA Medizintechnik GmbH, Gieίen, Germany) for calculation of blood flow velocity, hemoglobin oxygen saturation (SCO2) and relative hemoglobin concentration (rHb) in 2 and 8 mm depth. Contact-free remission spectroscopy (SkinREM3, Color Control Chemnitz GmbH, Chemnitz, Germany) allows contact free measurements in the VIS-NIR range of the spectrum (400 ± 1600 nm). Results: It is seen that therapeutic US is well tolerated. One patient dropped out from a treatment series since he developed erysipelas responding to standard antibiotic. Effects were seen at 34 kHz only. The SO2 values increased after single US application. The values for rHb were higher in the superficial layer of the wound bed (depth 2 mm) compared to deeper parts (8 mm depth). US treatment did not result in significant changes of rHb and blood cell velocity. The data obtained by remission spectroscopy disclose an increase of oxygenized hemoglobin. Conclusions: The major findings are that continuous-wave low-frequency US of 34 kHz, but not, 53.5 kHz or 75 kHz, has a temporary stimulatory effect on microcirculation mainly due to an improved oxygenation. Further studies with treatment series are necessary. PMID:21716543

Spatiotemporal Evolution of the Wound Repairing Process in a 3D Human Dermis Equivalent.

PubMed

Lombardi, Bernadette; Casale, Costantino; Imparato, Giorgia; Urciuolo, Francesco; Netti, Paolo Antonio

2017-07-01

Several skin equivalent models have been developed to investigate in vitro the re-epithelialization process occurring during wound healing. Although these models recapitulate closure dynamics of epithelial cells, they fail to capture how a wounded connective tissue rebuilds its 3D architecture until the evolution in a scar. Here, the in vitro tissue repair dynamics of a connective tissue is replicated by using a 3D human dermis equivalent (3D-HDE) model composed of fibroblasts embedded in their own extracellular matrix (ECM). After inducing a physical damage, 3D-HDE undergoes a series of cellular and extracellular events quite similar to those occurring in the native dermis. In particular, fibroblasts differentiation toward myofibroblasts phenotype and neosynthesis of hyaluronic acid, fibronectin, and collagen during the repair process are assessed. Moreover, tissue reorganization after physical damage is investigated by measuring the diameter of bundles and the orientation of fibers of the newly formed ECM network. Finally, the ultimate formation of a scar-like tissue as physiological consequence of the repair and closure process is demonstrated. Taking together, the results highlight that the presence of cell-assembled and responsive stromal components enables quantitative and qualitative in vitro evaluation of the processes involved in scarring during wound healing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High stability wavefront reference source

DOEpatents

Feldman, M.; Mockler, D.J.

1994-05-03

A thermally and mechanically stable wavefront reference source which produces a collimated output laser beam is disclosed. The output beam comprises substantially planar reference wavefronts which are useful for aligning and testing optical interferometers. The invention receives coherent radiation from an input optical fiber, directs a diverging input beam of the coherent radiation to a beam folding mirror (to produce a reflected diverging beam), and collimates the reflected diverging beam using a collimating lens. In a class of preferred embodiments, the invention includes a thermally and mechanically stable frame comprising rod members connected between a front end plate and a back end plate. The beam folding mirror is mounted on the back end plate, and the collimating lens mounted to the rods between the end plates. The end plates and rods are preferably made of thermally stable metal alloy. Preferably, the input optical fiber is a single mode fiber coupled to an input end of a second single mode optical fiber that is wound around a mandrel fixedly attached to the frame of the apparatus. The output end of the second fiber is cleaved so as to be optically flat, so that the input beam emerging therefrom is a nearly perfect diverging spherical wave. 7 figures.

High stability wavefront reference source

DOEpatents

Feldman, Mark; Mockler, Daniel J.

1994-01-01

A thermally and mechanically stable wavefront reference source which produces a collimated output laser beam. The output beam comprises substantially planar reference wavefronts which are useful for aligning and testing optical interferometers. The invention receives coherent radiation from an input optical fiber, directs a diverging input beam of the coherent radiation to a beam folding mirror (to produce a reflected diverging beam), and collimates the reflected diverging beam using a collimating lens. In a class of preferred embodiments, the invention includes a thermally and mechanically stable frame comprising rod members connected between a front end plate and a back end plate. The beam folding mirror is mounted on the back end plate, and the collimating lens mounted to the rods between the end plates. The end plates and rods are preferably made of thermally stable metal alloy. Preferably, the input optical fiber is a single mode fiber coupled to an input end of a second single mode optical fiber that is wound around a mandrel fixedly attached to the frame of the apparatus. The output end of the second fiber is cleaved so as to be optically flat, so that the input beam emerging therefrom is a nearly perfect diverging spherical wave.

[Effects of human amniotic epithelial stem cells-derived exosomes on healing of wound with full-thickness skin defect in rats].

PubMed

Zhao, B; Wu, G F; Zhang, Y J; Zhang, W; Yang, F F; Xiao, D; Zeng, K X; Shi, J H; Su, L L; Hu, D H

2017-01-20

Objective: To investigate the effects of human amniotic epithelial stem cells-derived exosomes on healing of wound with full-thickness skin defect in rats. Methods: (1) Human amniotic epithelial stem cells were isolated from the amnion tissue of 5 full-term pregnant women in Department of Obstetrics of our hospital by the method of trypsin digestion, and their morphology was observed. The third passage of cells were stained with rhodamine-phalloidin for cytoskeleton observation. The third passage of cells were identified with flow cytometry through the detection of expressions of cell surface markers CD29, CD31, CD34, CD90, CD105, SSEA3, SSEA4 and immunity-related marker human leukocyte antigen-D related site (HLA-DR). The third passage of cells were also assessed the ability of adipogenic and osteogenic differentiation. (2) The third passage of human amniotic epithelial stem cells were cultured in DMEM medium supplemented with 10% exosome-free fetal bovine serum. Exosomes were isolated from culture supernatant by the method of ultracentrifugation and represented with scanning electron microscope for morphologic observation. (3) Six adult SD rats were anesthetized, and four 1 cm×1 cm sized wounds with full-thickness skin defect were made on the back of each rat. The wounds on the back of each rat were divided into control group, 25 μg/mL exosomes group, 50 μg/mL exosomes group, and 100 μg/mL exosomes group according to the random number table (with 6 wounds in each group), and a total volume of 100 μL phosphate buffered saline, 25 μg/mL exosomes, 50 μg/mL exosomes, and 100 μg/mL exosomes were evenly injected around the wound through multiple subcutaneous sites, respectively. The wound healing rate was calculated based on measurement on post injury day (PID) 7, 14, and 21. On PID 21, the healed wound tissue of each group was collected and stained with HE to observe and count skin accessories, and the arrangement of collagen fibers was observed with Masson staining. Data were processed with analysis of variance for repeated measurement, analysis of variance of randomized block design, one-way analysis of variance, and Bonferroni test. Results: (1) The cells, which were isolated and cultured, displayed typical cobblestone morphology with many microvilli on cell surface. Among the cells, the positive expression rates of CD29, CD90, SSEA3, and SSEA4 were above 50.0%, and the rate of CD105 was 8.0%, while the rates of CD31, CD34, and HLA-DR were almost 0. The cells could differentiate into adipocytes and osteoblasts. The above results revealed that the cells cultured were human amniotic epithelial stem cells. (2) Human amniotic epithelial stem cells-derived exosomes were round or oval vesicles with diameter from 50 to 150 nm. (3) On PID 7 and 21, wound healing rates of the four groups were close (with P values above 0.05). On PID 14, wound healing rates of 50 and 100 μg/mL exosomes groups were (89.8±4.3)% and (92.0±4.6)% respectively, significantly higher than the wound healing rate of control group [(80.3±6.4)%, P <0.05 or P <0.01]. Moreover, the wound healing rate of 100 μg/mL exosomes group was significantly higher than that of 25 μg/mL exosomes group [(83.3±5.1)%, P <0.05]. On PID 21, the numbers of skin accessories in 50 and 100 μg/mL exosomes groups were 4.3±1.4 and 5.1±1.6 respectively, obviously more than those of control group and 25 μg/mL exosomes group (respectively 1.4±0.5 and 1.8±0.6, with P values below 0.01). Well reorganized collagen fibers were observed just in the healed wound tissue of 50 and 100 μg/mL exosomes groups. Conclusions: Human amniotic epithelial stem cells-derived exosomes can promote healing of wound with full-thickness skin defect in rats.

HMGB1 Promotes Intraoral Palatal Wound Healing through RAGE-Dependent Mechanisms

PubMed Central

Tancharoen, Salunya; Gando, Satoshi; Binita, Shrestha; Nagasato, Tomoka; Kikuchi, Kiyoshi; Nawa, Yuko; Dararat, Pornpen; Yamamoto, Mika; Narkpinit, Somphong; Maruyama, Ikuro

2016-01-01

High mobility group box 1 (HMGB1) is tightly connected to the process of tissue organization upon tissue injury. Here we show that HMGB1 controls epithelium and connective tissue regeneration both in vivo and in vitro during palatal wound healing. Heterozygous HMGB1 (Hmgb1+/−) mice and Wild-type (WT) mice were subjected to palatal injury. Maxillary tissues were stained with Mallory Azan or immunostained with anti-HMGB1, anti-proliferating cell nuclear antigen (PCNA), anti-nuclear factor-κB (NF-κB) p50 and anti-vascular endothelial growth factor (VEGF) antibodies. Palatal gingival explants were cultured with recombinant HMGB1 (rHMGB1) co-treated with siRNA targeting receptor for advanced glycation end products (RAGEs) for cell migration and PCNA expression analysis. Measurement of the wound area showed differences between Hmgb1+/− and WT mice on Day 3 after wounding. Mallory Azan staining showed densely packed of collagen fibers in WT mice, whereas in Hmgb1+/− mice weave-like pattern of low density collagen bundles were present. At three and seven days post-surgery, PCNA, NF-κB p50 and VEGF positive keratinocytes of WT mice were greater than that of Hmgb1+/− mice. Knockdown of RAGE prevents the effect of rHMGB1-induced cell migration and PCNA expression in gingival cell cultures. The data suggest that HMGB1/RAGE axis has crucial roles in palatal wound healing. PMID:27886093

[Study on preparation of laser micropore porcine acellular dermal matrix combined with split-thickness autograft and its application in wound transplantation].

PubMed

Liang, Li-Ming; Chai, Ji-Ke; Yang, Hong-Ming; Feng, Rui; Yin, Hui-Nan; Li, Feng-Yu; Sun, Qiang

2007-04-01

To prepare a porcine acellular dermal matrix (PADM), and to optimize the interpore distance between PADM and co-grafted split-thickness autologous skin. Porcine skin was treated with trypsin/Triton X-100 to prepare an acellular dermal matrix. Micropores were produced on the PADM with a laser punch. The distance between micropores varied as 0.8 mm, 1.0 mm, 1.2 mm and 1.5 mm. Full-thickness defect wounds were created on the back of 144 SD rats. The rats were randomly divided into 6 groups as follows, with 24 rats in each group. Micropore groups I -IV: the wounds were grafted with PADM with micropores in four different intervals respectively, and covered with split-thickness autologous skin graft. Mesh group: the wounds were grafted with meshed PADM and split-thickness autograft. with simple split-thickness autografting. The gross observation of wound healing and histological observation were performed at 2, 4, 6 weeks after surgery. The wound healing rate and contraction rate were calculated. Two and four weeks after surgery, the wound healing rate in micropore groups I and II was lower than that in control group (P < 0.05), but no obvious difference was between micropore groups I , II and mesh group (P > 0.05) until 6 weeks after grafting( P <0.05). The wound contraction rate in micropore groups I and II ([(16.0 +/- 2.6)%, (15.1 +/- 2.4)%] was remarkably lower than that in control group 4 and 6 weeks after grafting (P < 0.05), and it was significantly lower than that in mesh group [(19.3 +/- 2.4)%] 6 weeks after surgery (P <0.05). Histological examination showed good epithelization, regularly arranged collagenous fibers, and integral structure of basement membrane. Laser micropore PADM (0.8 mm or 1.0 mm in distance) grafting in combination with split-thickness autografting can improve the quality of wound healing. PADM with laser micropores in 1.0 mm distance is the best choice among them.

Safety profile of topical VEGF neutralization at the cornea.

PubMed

Bock, Felix; Onderka, Jasmine; Rummelt, Carmen; Dietrich, Tina; Bachmann, Björn; Kruse, Friedrich E; Schlötzer-Schrehardt, Ursula; Cursiefen, Claus

2009-05-01

Bevacizumab eyedrops inhibit corneal neovascularization. The purpose of this study was to analyze the safety profile of VEGF-A neutralization at the ocular surface. Bevacizumab eyedrops (5 mg/mL) and an antimurine VEGF-A antibody (250 microg/mL) were applied to normal murine corneas five times a day for 7 and 14 days. Subsequently, corneas were analyzed for morphologic changes by light and electron microscopy. In a mouse model of corneal epithelial abrasion, the effects of topically applied anti-VEGF antibodies on epithelial wound healing were analyzed: the treatment group received bevacizumab (5 mg/mL) or the antimurine VEGF-A antibody (250 microg/mL) as eyedrops, and the control group received an equal volume of saline solution. After 12, 18, and 24 hours, corneas were photographed in vivo with and without fluorescein staining for morphometry. Afterwards the mice were killed, and eyes were removed for histology, immunohistochemistry with Ki67/DAPI, and electron microscopy. The effect of midterm anti-VEGF therapy on corneal nerve density was assessed by staining corneas treated with an FITC-conjugated anti-neurofilament antibody and morphometric analysis. Murine corneas treated with two different types of anti-VEGF antibody eyedrops did not show obvious corneal morphologic changes at the light and electron microscopic levels. Furthermore, anti-VEGF antibody eyedrops had no significant impact on the wound healing process after corneal epithelial injury or on normal murine corneal nerve fiber density. Topical neutralization of VEGF-A at the corneal surface does not have significant side effects on normal corneal epithelial wound healing, normal corneal integrity, or normal nerve fiber density. Therefore, anti-VEGF eyedrops seem to be a relatively safe option to treat corneal neovascularization.

Pulse granuloma as a complication following dental trauma in children.

PubMed

Padmanabhan, Makkada Yuvaraj; Aparna, Radhakrishnan; Karthikeyani, Shanmugasundaram; Dinakar, Jayakumar; Manickaraj, Menaka

2013-01-01

Contamination and subsequent retention of foreign bodies within wound surfaces may negatively influence healing following maxillofacial injuries. Larger foreign bodies that produce embedded or impalement injuries of soft tissues are easily detected. However, smaller contaminants, such as sand, gravel, food particles, wood splinters, and glass fibers, may not be easily identified in the initial examination, and their remnants may remain within the injury site even after debridement. Tissue reactions depend on the host response, type of foreign body, and nature of the wound surface. The purposes of this report are to: (1) detail the diagnosis and management of a peripheral pulse granuloma following retention of food particles within gingival sulci during a dental injury; and (2) provide a brief review of the diagnosis of foreign body-induced granulomas following maxillofacial injuries in children.

A fracture mechanics analysis of impact damage in a thick composite laminate

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1985-01-01

Graphite/epoxy filament-wound cases (FWC) for the solid rocket motors of the space shuttle are being made by NASA. The FWC cases are wound with AS4W graphite fiber impregnated with an epoxy resin and are about 1.4 inches or more thick. Graphite-epoxy composite laminates, unlike metals, can be damaged easily by low velocity impacts of objects like dropped tools. The residual tension strength of the FWC laminate, after impact, is being studied at Langley Research Center. The conditions that give minimum visual evidence of damage are being emphasized. A fracture mechanics analysis was developed to predict the residual strength, after impact, using radiographs to measure the size of the damage and an equivalent surface crack to represent the damage.

Combined laser and photodynamic treatment in extensive purulent wounds

NASA Astrophysics Data System (ADS)

Solovieva, A. B.; Tolstih, P. I.; Melik-Nubarov, N. S.; Zhientaev, T. M.; Kuleshov, I. G.; Glagolev, N. N.; Ivanov, A. V.; Karahanov, G. I.; Tolstih, M. P.; Timashev, P. S.

2010-05-01

Recently, photodynamic therapy (PDT) has been used for the treatment of festering wounds and trophic ulcers. An important advantage of PDT is its ability to affect bacterial cultures that are resistant to antibiotics. However the use of PDT alone does not usually guarantee a stable antiseptic effect and cannot prevent an external infection of wounds and burns. In this work attention is focused on the healing of the extensive soft tissues wounds with combined laser therapy (LT) and PDT treatment. At the first stage of this process festering tissues (for example spacious purulent wounds with area more than 100 cm2) were illuminated with high-energy laser beam (with power 20 W) in continues routine. The second stage involves “softer” PDT affect, which along with the completion stages of destruction pathological cells, stimulating the process of wound granulation and epithelization. Also, according to our previous results, photosensitizer (photoditazin) is introduced inside the wound with different amphiphilic polymers for increasing the PDT efficacy.

Inflammation and wound healing: The role of the macrophage

PubMed Central

Koh, Timothy J.; DiPietro, Luisa Ann

2013-01-01

The macrophage is a prominent inflammatory cell in wounds, but its role in healing remains incompletely understood. Macrophages have been described to have many functions in wounds, including host defense, the promotion and resolution of inflammation, the removal of apoptotic cells, and the support of cell proliferation and tissue restoration following injury. Recent studies suggest that macrophages exist in several different phenotypic states within the healing wound, and that the influence of these cells on each stage of repair varies with the specific phenotypes. While the macrophage is beneficial to the repair of normally healing wounds, this pleotropic cell type may promote excessive inflammation and/or fibrosis in certain circumstances. Emerging evidence suggests that macrophage dysfunction is a component of the pathogenesis of non-healing and poorly healing wounds. Due to advances in the understanding of this multi-functional cell, the macrophage continues to be an attractive therapeutic target both to reduce fibrosis and scarring, and to improve healing of chronic wounds. PMID:21740602

The fatigue life study of polyphenylene sulfide composites filled with continuous glass fibers

NASA Astrophysics Data System (ADS)

Ye, Junjie; Hong, Yun; Wang, Yongkun; Zhai, Zhi; Shi, Baoquan; Chen, Xuefeng

2018-04-01

In this study, an effective microscopic model is proposed to investigate the fatigue life of composites containing continuous glass fibers, which is surrounded by polyphenylene sulfide (PPS) matrix materials. The representative volume element is discretized by parametric elements. Moreover, the microscopic model is established by employing the relation between average surface displacements and average surface tractions. Based on the experimental data, the required fatigue failure parameters of the PPS are determined. Two different fiber arrangements are considered for comparisons. Numerical analyses indicated that the square edge packing provides a more accuracy. In addition, microscopic structural parameters (fiber volume fraction, fiber off-axis angle) effect on the fatigue life of Glass/PPS composites is further discussed. It is revealed that fiber strength degradation effects on the fatigue life of continuous fiber-reinforced composites can be ignored.

Filament Winding Multifunctional Carbon Nanotube Composites of Various Dimensionality

NASA Astrophysics Data System (ADS)

Wells, Brian David

Carbon nanotubes (CNT) have been long considered an optimal material for composites due to their high strength, high modulus, and electrical/thermal conductivity. These composite materials have the potential to be used in the aerospace, computer, automotive, medical industry as well as many others. The nano dimensions of these structures make controlled alignment and distribution difficult using many production techniques. An area that shows promise for controlled alignment is the formation of CNT yarns. Different approaches have been used to create yarns with various winding angles and diameters. CNTs resemble traditional textile fiber structures due to their one-dimensional dimensions, axial strength and radial flexibility. One difference is, depending on the length, CNTs can have aspect ratios that far exceed those of traditional textile fibers. This can complicate processing techniques and cause agglomeration which prevents optimal structures from being created. However, with specific aspect ratios and spatial distributions a specific type of CNT, vertically aligned spinnable carbon nanotubes (VASCNTs), have interesting properties that allow carbon nanotubes to be drawn from an array in a continuous aligned web. This dissertation examines the feasibility of combining VASCNTs with another textile manufacturing process, filament winding, to create structures with various levels of dimensionality. While yarn formation with CNTs has been largely studied, there has not been significant work studying the use of VASCNTs to create composite materials. The studies that have been produces revolve around mixing CNTs into epoxy or creating uni-directional wound structures. In this dissertation VASCNTs are used to create filament wound materials with various degrees of alignment. These structures include 1 dimensional coatings applied to non-conductive polymer monofilaments, two dimensional multifunctional adhesive films, and three dimensional hybrid-nano composites. The angle of alignment between the individual CNTs relative to the overall structure was used to affect the electrical properties in all of these structures and the mechanical properties of the adhesive films and hybrid-nano composites. Varying the concentration of CNT was also found to have a significant effect on the electrical and mechanical properties. The variable properties that can be created with these production techniques allow users to engineer the structure to match the desired property.

Low Cost Inkjet Printed Smart Bandage for Wireless Monitoring of Chronic Wounds

PubMed Central

Farooqui, Muhammad Fahad; Shamim, Atif

2016-01-01

Chronic wounds affect millions of patients around the world and their treatment is challenging as the early signs indicating their development are subtle. In addition, a type of chronic wound, known as pressure ulcer, develops in patients with limited mobility. Infection and frequent bleeding are indicators of chronic wound development. In this article, we present an unprecedented low cost continuous wireless monitoring system, realized through inkjet printing on a standard bandage, which can send early warnings for the parameters like irregular bleeding, variations in pH levels and external pressure at wound site. In addition to the early warnings, this smart bandage concept can provide long term wound progression data to the health care providers. The smart bandage comprises a disposable part which has the inkjet printed sensors and a reusable part constituting the wireless electronics. This work is an important step towards futuristic wearable sensors for remote health care applications. PMID:27353200

Low Cost Inkjet Printed Smart Bandage for Wireless Monitoring of Chronic Wounds

NASA Astrophysics Data System (ADS)

Farooqui, Muhammad Fahad; Shamim, Atif

2016-06-01

Chronic wounds affect millions of patients around the world and their treatment is challenging as the early signs indicating their development are subtle. In addition, a type of chronic wound, known as pressure ulcer, develops in patients with limited mobility. Infection and frequent bleeding are indicators of chronic wound development. In this article, we present an unprecedented low cost continuous wireless monitoring system, realized through inkjet printing on a standard bandage, which can send early warnings for the parameters like irregular bleeding, variations in pH levels and external pressure at wound site. In addition to the early warnings, this smart bandage concept can provide long term wound progression data to the health care providers. The smart bandage comprises a disposable part which has the inkjet printed sensors and a reusable part constituting the wireless electronics. This work is an important step towards futuristic wearable sensors for remote health care applications.

Low Cost Inkjet Printed Smart Bandage for Wireless Monitoring of Chronic Wounds.

PubMed

Farooqui, Muhammad Fahad; Shamim, Atif

2016-06-29

Chronic wounds affect millions of patients around the world and their treatment is challenging as the early signs indicating their development are subtle. In addition, a type of chronic wound, known as pressure ulcer, develops in patients with limited mobility. Infection and frequent bleeding are indicators of chronic wound development. In this article, we present an unprecedented low cost continuous wireless monitoring system, realized through inkjet printing on a standard bandage, which can send early warnings for the parameters like irregular bleeding, variations in pH levels and external pressure at wound site. In addition to the early warnings, this smart bandage concept can provide long term wound progression data to the health care providers. The smart bandage comprises a disposable part which has the inkjet printed sensors and a reusable part constituting the wireless electronics. This work is an important step towards futuristic wearable sensors for remote health care applications.

New Guar Biopolymer Silver Nanocomposites for Wound Healing Applications

PubMed Central

Abdullah, Md Farooque; Das, Suvadra; Roy, Partha; Datta, Sriparna; Mukherjee, Arup

2013-01-01

Wound healing is an innate physiological response that helps restore cellular and anatomic continuity of a tissue. Selective biodegradable and biocompatible polymer materials have provided useful scaffolds for wound healing and assisted cellular messaging. In the present study, guar gum, a polymeric galactomannan, was intrinsically modified to a new cationic biopolymer guar gum alkylamine (GGAA) for wound healing applications. Biologically synthesized silver nanoparticles (Agnp) were further impregnated in GGAA for extended evaluations in punch wound models in rodents. SEM studies showed silver nanoparticles well dispersed in the new guar matrix with a particle size of ~18 nm. In wound healing experiments, faster healing and improved cosmetic appearance were observed in the new nanobiomaterial treated group compared to commercially available silver alginate cream. The total protein, DNA, and hydroxyproline contents of the wound tissues were also significantly higher in the treated group as compared with the silver alginate cream (P < 0.05). Silver nanoparticles exerted positive effects because of their antimicrobial properties. The nanobiomaterial was observed to promote wound closure by inducing proliferation and migration of the keratinocytes at the wound site. The derivatized guar gum matrix additionally provided a hydrated surface necessary for cell proliferation. PMID:24175306

New guar biopolymer silver nanocomposites for wound healing applications.

PubMed

Ghosh Auddy, Runa; Abdullah, Md Farooque; Das, Suvadra; Roy, Partha; Datta, Sriparna; Mukherjee, Arup

2013-01-01

Wound healing is an innate physiological response that helps restore cellular and anatomic continuity of a tissue. Selective biodegradable and biocompatible polymer materials have provided useful scaffolds for wound healing and assisted cellular messaging. In the present study, guar gum, a polymeric galactomannan, was intrinsically modified to a new cationic biopolymer guar gum alkylamine (GGAA) for wound healing applications. Biologically synthesized silver nanoparticles (Agnp) were further impregnated in GGAA for extended evaluations in punch wound models in rodents. SEM studies showed silver nanoparticles well dispersed in the new guar matrix with a particle size of ~18 nm. In wound healing experiments, faster healing and improved cosmetic appearance were observed in the new nanobiomaterial treated group compared to commercially available silver alginate cream. The total protein, DNA, and hydroxyproline contents of the wound tissues were also significantly higher in the treated group as compared with the silver alginate cream (P < 0.05). Silver nanoparticles exerted positive effects because of their antimicrobial properties. The nanobiomaterial was observed to promote wound closure by inducing proliferation and migration of the keratinocytes at the wound site. The derivatized guar gum matrix additionally provided a hydrated surface necessary for cell proliferation.

An Overview of the Efficacy of a Next Generation Electroceutical Wound Care Device.

PubMed

Kim, Hosan; Park, Soon; Housler, Greggory; Marcel, Vanessa; Cross, Sue; Izadjoo, Mina

2016-05-01

Novel approaches including nonpharmacological methodologies for prevention and control of microbial pathogens and emerging antibiotic resistance are urgently needed. Procellera is a wound care device consisting of a matrix of alternating silver (Ag) and zinc (Zn) dots held in position on a polyester substrate with a biocompatible binder. This electroceutical medical device is capable of generating a direct current voltage (0.5-0.9 Volts). Wound dressings containing metals such as Ag and/or Zn as active ingredients are being used for control of colonized and infected wounds. Reports on the presence of electric potential field across epithelium and wound current on wounding have shown that wound healing is enhanced in the presence of an external electrical field. However, majority of the electrical devices require an external power source for delivering pulsed or continuous electric power at the wound site. A microelectric potential-generating system without an external power source is an ideal treatment modality for application in both clinical and field settings. The research presented herein describes efficacy evaluation of a wireless bioelectric dressing against both planktonic and biofilm forms of wound pathogens including multidrug resistant organisms. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Clinical Impact Upon Wound Healing and Inflammation in Moist, Wet, and Dry Environments

PubMed Central

Junker, Johan P.E.; Kamel, Rami A.; Caterson, E.J.; Eriksson, Elof

2013-01-01

Significance Successful treatment of wounds relies on precise control and continuous monitoring of the wound-healing process. Wet or moist treatment of wounds has been shown to promote re-epithelialization and result in reduced scar formation, as compared to treatment in a dry environment. Recent Advances By treating wounds in a controlled wet environment, delivery of antimicrobials, analgesics, other bioactive molecules such as growth factors, as well as cells and micrografts, is allowed. The addition of growth factors or transplantation of cells yields the possibility of creating a regenerative wound microenvironment that favors healing, as opposed to excessive scar formation. Critical Issues Although several manufacturers have conceived products implementing the concept of moist wound healing, there remains a lack of commercial translation of wet wound-healing principles into clinically available products. This can only be mitigated by further research on the topic. Future Directions The strong evidence pointing to the favorable healing of wounds in a wet or moist environment compared to dry treatment will extend the clinical indications for this treatment. Further advances are required to elucidate by which means this microenvironment can be optimized to improve the healing outcome. PMID:24587972

Hair sparing does not compromise real-time magnetic resonance imaging guided stereotactic laser fiber placement for temporal lobe epilepsy.

PubMed

Singh, Shikha; Kumar, Kevin K; Rabon, Matthew J; Dolce, Dana; Halpern, Casey H

2018-06-01

Pre-operative scalp shaving is conventionally thought to simplify postoperative cranial wound care, lower the rate of wound infections, and ease optimal incision localization. Over the past few decades, some neurosurgeons have refrained from scalp shaving in order to improve patient satisfaction with brain surgery. However, this hair-sparing approach has not yet been explored in the growing field of magnetic resonance-guided laser interstitial thermal therapy (MRgLITT). This study investigated the initial impact of a no-shave technique on post-operative wound infection rate as well as on entry and target accuracy in MRgLITT for mesial temporal epilepsy. Eighteen patients selected by the Stanford Comprehensive Epilepsy Program between November 2015 and August 2017 were included in the study. All patients underwent functional selective amygdalohippocampotomies using MRgLITT entirely within a diagnostic MRI suite. No hair was removed and no additional precautions were taken for hair or scalp care. Otherwise, routine protocols for surgical preparations and wound closure were followed. The study was performed under approval from Stanford University's Internal Review Board (IRB-37830). No post-operative wound infections or erosions occurred for any patient. The mean entry point error was 2.87 ± 1.3 mm and the mean target error was 1.0 ± 0.9 mm. There have been no other complications associated with this hair-sparing approach. The study's results suggest that hair sparing in MRgLITT surgery for temporal epilepsy does not increase the risk of wound complications or compromise accuracy. This preferred cosmetic approach may thus appeal to epilepsy patients considering such interventions. Copyright © 2018 Elsevier Ltd. All rights reserved.

In Vitro Assessment of the Antibacterial Potential of Silver Nano-Coatings on Cotton Gauzes for Prevention of Wound Infections

PubMed Central

Paladini, Federica; Di Franco, Cinzia; Panico, Angelica; Scamarcio, Gaetano; Sannino, Alessandro; Pollini, Mauro

2016-01-01

Multidrug-resistant organisms are increasingly implicated in acute and chronic wound infections, thus compromising the chance of therapeutic options. The resistance to conventional antibiotics demonstrated by some bacterial strains has encouraged new approaches for the prevention of infections in wounds and burns, among them the use of silver compounds and nanocrystalline silver. Recently, silver wound dressings have become widely accepted in wound healing centers and are commercially available. In this work, novel antibacterial wound dressings have been developed through a silver deposition technology based on the photochemical synthesis of silver nanoparticles. The devices obtained are completely natural and the silver coatings are characterized by an excellent adhesion without the use of any binder. The silver-treated cotton gauzes were characterized through scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA) in order to verify the distribution and the dimension of the silver particles on the cotton fibers. The effectiveness of the silver-treated gauzes in reducing the bacterial growth and biofilm proliferation has been demonstrated through agar diffusion tests, bacterial enumeration test, biofilm quantification tests, fluorescence and SEM microscopy. Moreover, potential cytotoxicity of the silver coating was evaluated through 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide colorimetric assay (MTT) and the extract method on fibroblasts and keratinocytes. Inductively coupled plasma mass spectrometry (ICP-MS) was performed in order to determine the silver release in different media and to relate the results to the biological characterization. All the results obtained were compared with plain gauzes as a negative control, as well as gauzes treated with a higher silver percentage as a positive control. PMID:28773531

Analgesia with interfascial continuous wound infiltration after laparoscopic colon surgery: A randomized clinical trial.

PubMed

Telletxea, S; Gonzalez, J; Portugal, V; Alvarez, R; Aguirre, U; Anton, A; Arizaga, A

2016-04-01

For major laparoscopic surgery, as with open surgery, a multimodal analgesia plan can help to control postoperative pain. Placing a wound catheter intraoperatively following colon surgery could optimize the control of acute pain with less consumption of opioids and few adverse effects. We conducted a prospective, randomized, study of patients scheduled to undergo laparoscopic colon surgery for cancer in Galdakao-Usansolo Hospital from January 2012 to January 2013. Patients were recruited and randomly allocated to wound catheter placement plus standard postoperative analgesia or standard postoperative analgesia alone. A physician from the acute pain management unit monitored all patients for pain at multiple points over the first 48 hours after surgery. The primary outcome variables were verbal numeric pain scale scores and amount of intravenous morphine used via patient controlled infusion. 92 patients were included in the study, 43 had a wound catheter implanted and 49 did not. Statistically significant differences in morphine consumption were observed between groups throughout the course of the treatment period. The mean total morphine consumption at the end of the study was 5.63±5.02mg among wound catheter patients and 21. 86±17.88mg among control patients (P=.0001). Wound catheter patients had lower pain scale scores than control patients throughout the observation period. No adverse effects associated with the wound catheter technique were observed. The wound catheter group showed lower hospital stays with statistically significant difference (P=.02). In patients undergoing laparoscopic colon surgery, continuous infusion of local anaesthetics through interfascial wound catheters during the first 48h aftersurgery reduced the level of perceived pain and also reduced parenteral morphine consumption with no associated adverse effects and lower hospital stays. Copyright © 2015 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Research on Damage Models for Continuous Fiber Composites

DTIC Science & Technology

1988-07-01

r ~.F (~ Mechanics and Materials Center TEXAS A&M UNIVERSITY College Station, Texas RESEARCH ON DAMAGE MODELS FOR CONTINUOUS FIBER COMPOSITES Final...Washington, DC 20332 11. TITLE (Include Security Clas=fication) Research on Damage Models for Continuous Fiber Composites - Final Technical Report 1...GROUP SUB-GROU ::=, COMPOsites ) continuum mechanics , ~ idamage, internal state variables V experimental mechanics, laminated composites o 19. ABSTRACT

21 CFR 878.4022 - Hydrogel wound dressing and burn dressing.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hydrogel wound dressing and burn dressing. 878.4022 Section 878.4022 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4022...

21 CFR 878.4022 - Hydrogel wound dressing and burn dressing.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hydrogel wound dressing and burn dressing. 878.4022 Section 878.4022 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4022...

21 CFR 878.4022 - Hydrogel wound dressing and burn dressing.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hydrogel wound dressing and burn dressing. 878.4022 Section 878.4022 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4022...

21 CFR 878.4011 - Tissue adhesive with adjunct wound closure device for topical approximation of skin.

Code of Federal Regulations, 2011 CFR

2011-04-01

... ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY... approximated skin edges of wounds from surgical incisions, including punctures from minimally invasive surgery, and simple, thoroughly cleansed, trauma-induced lacerations. It may be used in conjunction with, but...

Electrospinning of Biocompatible Nanofibers

NASA Astrophysics Data System (ADS)

Coughlin, Andrew J.; Queen, Hailey A.; McCullen, Seth D.; Krause, Wendy E.

2006-03-01

Artificial scaffolds for growing cells can have a wide range of applications including wound coverings, supports in tissue cultures, drug delivery, and organ and tissue transplantation. Tissue engineering is a promising field which may resolve current problems with transplantation, such as rejection by the immune system and scarcity of donors. One approach to tissue engineering utilizes a biodegradable scaffold onto which cells are seeded and cultured, and ideally develop into functional tissue. The scaffold acts as an artificial extracellular matrix (ECM). Because a typical ECM contains collagen fibers with diameters of 50-500 nm, electrostatic spinning (electrospinning) was used to mimic the size and structure of these fibers. Electrospinning is a novel way of spinning a nonwoven web of fibers on the order of 100 nm, much like the web of collagen in an ECM. We are investigating the ability of several biocompatible polymers (e.g., chitosan and polyvinyl alcohol) to form defect-free nanofiber webs and are studying the influence of the zero shear rate viscosity, molecular weight, entanglement concentration, relaxation time, and solvent on the resulting fiber size and morphology.

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

DOE PAGES

Lomperski, Stephen; Gerardi, Craig; Pointer, William David

2015-03-04

In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points overmore » a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.« less

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lomperski, Stephen; Gerardi, Craig; Pointer, William David

In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points overmore » a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.« less

Electrospun curcumin-loaded cellulose acetate/polyvinylpyrrolidone fibrous materials with complex architecture and antibacterial activity.

PubMed

Tsekova, Petya B; Spasova, Mariya G; Manolova, Nevena E; Markova, Nadya D; Rashkov, Iliya B

2017-04-01

Novel fibrous materials from cellulose acetate (CA) and polyvinylpyrrolidone (PVP) containing curcumin (Curc) with original design were prepared by one-pot electrospinning or dual spinneret electrospinning. The electrospun materials were characterized by scanning electron microscopy (SEM), fluorescence microscopy, Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), differential scanning calorimetry (DSC), water contact angle measurements, and microbiological tests. It was found that the incorporation of Curc into the CA and PVP solutions resulted in an increase of the solution viscosity and obtaining fibers with larger diameters (ca. 1.5μm) compared to the neat CA (ca. 800nm) and PVP fibers (ca. 500nm). The incorporation of PVP resulted in increased hydrophilicity of the fibers and in faster Curc release. Curc was found in the amorphous state in the Curc-containing fibers and these mats exhibited antibacterial activity against Staphylococcus aureus (S. aureus). The results suggest that, due to their complex architecture, the obtained new antibacterial materials are suitable for wound dressing applications, which necessitate diverse release behaviors of the bioactive compound. Copyright © 2016 Elsevier B.V. All rights reserved.

Fast Burn Booster Technology

DTIC Science & Technology

1992-05-21

phenolic resin. The warp/fill primary structure laminate plies are laid up next followed by the exit cone bias involute. The subassembly was vacuum bagged...CARBON FIBER/EPOXT 7075-T73 ALUMINUM 7kCo4x>€ axmjtuma* ROUNDING RING CARBON PHENOLIC INVOLUTE CARBON PHENOLIC LAMINATED INSULATION. MXSI-55...DESIGNS AND CURRENT STATUS *n ,.Wn„nd Composite Case. The older Sentry motor design employed a hybrid ( Kevlar -graphlte) fUament-wound ewe. *« S

Sealing Penetrating Eye Injuries With Photoactivated Bonding

DTIC Science & Technology

2013-09-01

penetrating eye injuries. Scope: To establish, in ex vitro and in vivo animal models, the treatment parameters for sealing corneal and scleral...cornea surface was compared to that produced by our conventional, bare fiber system using ex vivo rabbit eyes and the standard treatment protocol...Identified the PTB treatment parameters that produce strong bonding of an amnion patch over corneal wounds in ex vivo rabbit eyes . • Determined that a

Monitoring soft tissue coagulation by optical spectroscopy

NASA Astrophysics Data System (ADS)

Lihachev, A.; Lihacova, I.; Heinrichs, H.; Spigulis, J.; Trebst, T.; Wehner, M.

2017-12-01

Laser tissue welding (LTW) or laser tissue soldering (LTS) is investigated since many years for treatment of incisions, wound closure and anastomosis of vessels [1, 2]. Depending on the process, a certain temperature in the range between 65 °C to 85 °C must be reached and held for a few seconds. Care has to be taken not to overheat the tissue, otherwise necrosis or tissue carbonization may occur and will impair wound healing. Usually the temperature is monitored during the process to control the laser power [3]. This requires either bulky equipment or expensive and fragile infrared fibers to feed the temperature signal to an infrared detector. Alternatively, changes in tissue morphology can be directly observed by analysis of spectral reflectance. We investigate spectral changes in the range between 400 nm to 900 nm wavelength. Characteristic spectral changes occur when the temperature of tissue samples increase above 70 °C which is a typical setpoint value for temperature control of coagulation. We conclude that simple spectroscopy in the visible range can provide valuable information during LTS and LTW and probably replace the delicate measurement of temperature. A major advantage is that optical measurements can be performed using standard optical fibers and can be easily integrated into a surgical tool.

Electrospinning of Nanodiamond-Modified Polysaccharide Nanofibers with Physico-Mechanical Properties Close to Natural Skins

PubMed Central

Mahdavi, Mina; Mahmoudi, Nafiseh; Rezaie Anaran, Farzad; Simchi, Abdolreza

2016-01-01

Electrospinning of biopolymers has gained significant interest for the fabrication of fibrous mats for potential applications in tissue engineering, particularly for wound dressing and skin regeneration. In this study, for the first time, we report successful electrospinning of chitosan-based biopolymers containing bacterial cellulous (33 wt %) and medical grade nanodiamonds (MND) (3 nm; up to 3 wt %). Morphological studies by scanning electron microscopy showed that long and uniform fibers with controllable diameters from 80 to 170 nm were prepared. Introducing diamond nanoparticles facilitated the electrospinning process with a decrease in the size of fibers. Fourier transform infrared spectroscopy determined hydrogen bonding between the polymeric matrix and functional groups of MND. It was also found that beyond 1 wt % MND, percolation networks of nanoparticles were formed which affected the properties of the nanofibrous mats. Uniaxial tensile testing of the woven mats determined significant enhancement of the strength (from 13 MPa to 25 MP) by dispersion of 1 wt % MND. The hydrophilicity of the mats was also remarkably improved, which was favorable for cell attachment. The water vapor permeability was tailorable in the range of 342 to 423 µg·Pa−1·s−1·m−1. The nanodiamond-modified mats are potentially suitable for wound healing applications. PMID:27399726

Continuous self-locking spiral wound seal. [for maintaining pressure between chambers in cryogenic wind tunnels

NASA Technical Reports Server (NTRS)

Irick, S. C. (Inventor)

1982-01-01

A spiral wound seal for effecting a seal between two surfaces is described. The seal consists of a strip of gasket material wound into a groove machined into one of the surfaces. The gasket strip is wider than the groove is deep so that a portion of the gasket material protrudes from the groove. The seal is effected by clamping the second surface onto the first surface and compressing the protruding gasket material.

Method for the continuous processing of hermetic fiber optic components and the resultant fiber optic-to-metal components

DOEpatents

Kramer, D.P.

1994-08-09

Hermetic fiber optic-to-metal components and method for making hermetic fiber optic-to-metal components by assembling and fixturing elements comprising a metal shell, a glass preform, and a metal-coated fiber optic into desired relative positions and then sealing said fixtured elements preferably using a continuous heating process is disclosed. The resultant hermetic fiber optic-to-metal components exhibit high hermeticity and durability despite the large differences in thermal coefficients of expansion among the various elements. 3 figs.

Micro-management: curbing chronic wound infection.

PubMed

Withycombe, C; Purdy, K J; Maddocks, S E

2017-08-01

Chronic wounds, including pressure ulcers, foot ulcers, and venous leg ulcers, have a detrimental impact on the health and well-being of an estimated 2% of people in the UK. Chronic wounds are normally colonized by bacteria and in some instances bacterial load increases sufficiently for infection to ensue. Once a chronic wound becomes infected it is difficult to resolve and a combination of continuous inflammation and bacterial proliferation makes these wounds difficult to manage. A state of prolonged inflammation can occur as a result of impaired homeostatic pathways, which are exacerbated by bacterial growth. Chronic, infected wounds can persist for many months or even years, sometimes requiring surgical intervention in the form of regular debridement or amputation when other strategies such as antimicrobial treatments fail. The complex relationships between both oral microbiota and the host have been extensively characterized, including the shift from health to disease, and this has allowed the development of numerous control strategies. This knowledge, combined with contemporary studies of chronic infected wounds, can be used to develop an understanding of the relationship between the host and microorganism in the chronic wound environment. Such information has the potential to inform wound management including strategies to control infection and promote wound healing. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Palliative wound care management strategies for palliative patients and their circles of care.

PubMed

Woo, Kevin Y; Krasner, Diane L; Kennedy, Bruce; Wardle, David; Moir, Olivia

2015-03-01

To provide information about palliative wound care management strategies for palliative patients and their circles of care. This continuing education activity is intended for physicians and nurses with an interest in skin and wound care. After participating in this educational activity, the participant should be better able to: 1. Recognize study findings, assessment tools, and non-pharmacologic strategies used for patients with palliative wounds. 2. Summarize pharmacologic and dressing treatment strategies used for wound care management of palliative patients. The principles of palliative wound care should be integrated along the continuum of wound care to address the whole person care needs of palliative patients and their circles of care, which includes members of the patient unit including family, significant others, caregivers, and other healthcare professionals that may be external to the current interprofessional team. Palliative patients often present with chronic debilitating diseases, advanced diseases associated with major organ failure (renal, hepatic, pulmonary, or cardiac), profound dementia, complex psychosocial issues, diminished self-care abilities, and challenging wound-related symptoms. This article introduces key concepts and strategies for palliative wound care that are essential for interprofessional team members to incorporate in clinical practice when caring for palliative patients with wounds and their circles of care.

Randomized clinical trial to compare negative-pressure wound therapy approaches with low and high pressure, silicone-coated dressing, and polyurethane foam dressing.

PubMed

Lavery, Lawrence A; La Fontaine, Javier; Thakral, Gaurav; Kim, Paul J; Bhavan, Kavita; Davis, Kathryn E

2014-03-01

This study was designed to compare two approaches to negative-pressure wound therapy: 125-mmHg pressure with a polyurethane foam dressing and 75-mmHg pressure with a silicone-coated dressing. Forty patients with diabetic foot wounds, after incision and drainage or amputation for infection, were assigned randomly to negative-pressure wound therapy with 75-mmHg continuous pressure with a silicone-covered dressing (75-mmHg group) or 125-mmHg with a polyurethane foam dressing (125-mmHg group) for up to 4 weeks or until surgical closure. There was no difference in the proportion of wounds that were closed surgically (75-mmHg group, 50 percent; 125-mmHg group, 60 percent), wounds that demonstrated 50 percent wound area reduction (75-mmHg group, 65 percent; 125-mmHg group, 80 percent), or wounds that demonstrated 50 percent wound volume reduction after 4 weeks of therapy (75-mmHg group, 95 percent; 125-mmHg group, 90 percent). The authors' results suggest that there was no difference in outcomes in wounds treated with low pressure (75 mmHg) with a silicone-coated interface and high pressure (125 mmHg) with a polyurethane foam interface. Therapeutic, II.

Cell Migration in 1D and 2D Nanofiber Microenvironments.

PubMed

Estabridis, Horacio M; Jana, Aniket; Nain, Amrinder; Odde, David J

2018-03-01

Understanding how cells migrate in fibrous environments is important in wound healing, immune function, and cancer progression. A key question is how fiber orientation and network geometry influence cell movement. Here we describe a quantitative, modeling-based approach toward identifying the mechanisms by which cells migrate in fibrous geometries having well controlled orientation. Specifically, U251 glioblastoma cells were seeded onto non-electrospinning Spinneret based tunable engineering parameters fiber substrates that consist of networks of suspended 400 nm diameter nanofibers. Cells were classified based on the local fiber geometry and cell migration dynamics observed by light microscopy. Cells were found in three distinct geometries: adhering two a single fiber, adhering to two parallel fibers, and adhering to a network of orthogonal fibers. Cells adhering to a single fiber or two parallel fibers can only move in one dimension along the fiber axis, whereas cells on a network of orthogonal fibers can move in two dimensions. We found that cells move faster and more persistently in 1D geometries than in 2D, with cell migration being faster on parallel fibers than on single fibers. To explain these behaviors mechanistically, we simulated cell migration in the three different geometries using a motor-clutch based model for cell traction forces. Using nearly identical parameter sets for each of the three cases, we found that the simulated cells naturally replicated the reduced migration in 2D relative to 1D geometries. In addition, the modestly faster 1D migration on parallel fibers relative to single fibers was captured using a correspondingly modest increase in the number of clutches to reflect increased surface area of adhesion on parallel fibers. Overall, the integrated modeling and experimental analysis shows that cell migration in response to varying fibrous geometries can be explained by a simple mechanical readout of geometry via a motor-clutch mechanism.

System to continuously produce carbon fiber via microwave assisted plasma processing

DOEpatents

White, Terry L; Paulauskas, Felix L; Bigelow, Timothy S

2014-03-25

A method for continuously processing carbon fiber including establishing a microwave plasma in a selected atmosphere contained in an elongated chamber having a microwave power gradient along its length defined by a lower microwave power at one end and a higher microwave power at the opposite end of the elongated chamber. The elongated chamber having an opening in each of the ends of the chamber that are adapted to allow the passage of the fiber tow while limiting incidental gas flow into or out of said chamber. A continuous fiber tow is introduced into the end of the chamber having the lower microwave power. The fiber tow is withdrawn from the opposite end of the chamber having the higher microwave power. The fiber to is subjected to progressively higher microwave energy as the fiber is being traversed through the elongated chamber.

Composite ceramic superconducting wires for electric motor applications

NASA Astrophysics Data System (ADS)

Halloran, John W.

1988-12-01

This is the Second Quarterly report on a project to develop HTSC wire for an HTSC motor. The raw material for fiber production is an improved YBa2Cu3O(7-x) powder. Continuous spools of green YBa2Cu3O(7-x) fiber are being produced. The major effort in fiber spinning is aimed at improving fiber quality and reducing fiber. Binder burnout and sintering has been intensively investigated. Fiber sintering fibers is done by the rapid zone sintering method. A continuous furnace received near the end of this Quarter will be used for continuous sintering. Continuous silver coated green fiber are produced. We have made progress toward continuous cladding using the mechanical cladding concept. The melt spinning process was successfully applied to YBa2Cu3O(7-x) powders at 50 vol percent solids loadings. The cladding work centered on mechanical cladding of silver treated filaments by solder bonding to copper strips. Aluminum deposits on YBa2Cu3O(7-x) filament surfaces were produced by MOCVD at ATM, but the superconductivity was degraded. Electrical characterization work focused on methods of making low resistance contacts on YBa2Cu3O(7-x) filaments. Emerson Motor Division has begun work on DC heteropolar and homopolar motor designs. The mechanical stresses on conventional copper wires during winding have been characterized to determine the mechanical parameters of motor building.

Stimulated Brillouin scattering continuous wave phase conjugation in step-index fiber optics.

PubMed

Massey, Steven M; Spring, Justin B; Russell, Timothy H

2008-07-21

Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber NA(2), but find that fidelity remains high over much longer fiber lengths than previous models calculated. Conditions for SBS beam cleanup in step-index fibers are discussed.

Ephrin-B2 is differentially expressed in the intestinal epithelium in Crohn’s disease and contributes to accelerated epithelial wound healing in vitro

PubMed Central

Hafner, Christian; Meyer, Stefanie; Langmann, Thomas; Schmitz, Gerd; Bataille, Frauke; Hagen, Ilja; Becker, Bernd; Roesch, Alexander; Rogler, Gerhard; Landthaler, Michael; Vogt, Thomas

2005-01-01

AIM: Eph receptor tyrosine kinases and their membrane bound receptor-like ligands, the ephrins, represent a bi-directional cell-cell contact signaling system that directs epithelial movements in development. The meaning of this system in the adult human gut is unknown. We investigated the Eph/ephrin mRNA expression in the intestinal epithelium of healthy controls and patients with inflammatory bowel disease (IBD). METHODS: mRNA expression profiles of all Eph/ephrin family members in normal small intestine and colon were established by real-time RT-PCR. In addition, differential expression in IBD was investigated by cDNA array technology, and validated by both real-time RT-PCR and immunohistochemistry. Potential effects of enhanced EphB/ephrin-B signaling were analyzed in an in vitro IEC-6 cell scratch wound model. RESULTS: Human adult intestinal mucosa exhibits a complex pattern of Eph receptors and ephrins. Beside the known prominent co-expression of EphA2 and ephrinA1, we found abundantly co-expressed EphB2 and ephrin-B1/2. Interestingly, cDNA array data, validated by real-time PCR and immunohistochemistry, showed upregulation of ephrin-B2 in both perilesional and lesional intestinal epithelial cells of IBD patients, suggesting a role in epithelial homeostasis. Stimulation of ephrin-B signaling in ephrin-B1/2 expressing rat IEC-6-cells with recombinant EphB1-Fc resulted in a significant dose-dependent acceleration of wound closure. Furthermore, fluorescence microscopy showed that EphB1-Fc induced coordinated migration of wound edge cells is associated with enhanced formation of lamellipodial protrusions into the wound, increased actin stress fiber assembly and production of laminin at the wound edge. CONCLUSION: EphB/ephrin-B signaling might represent a novel protective mechanism that promotes intestinal epithelial wound healing, with potential impact on epithelial restitution in IBD. PMID:15996027

Lipid Emulsion Enriched in Omega-3 PUFA Accelerates Wound Healing: A Placebo-Controlled Animal Study.

PubMed

Peng, Yi-Chi; Yang, Fwu-Lin; Subeq, Yi-Maun; Tien, Chin-Chieh; Chao, Yann-Fen C; Lee, Ru-Ping

2018-06-01

The Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) generate bioactive lipid mediators that reduce inflammation. The present study evaluated the effect of SMOFlipid containing ω-3 PUFAs on wound healing. Rats were divided into a SMOFlipid (SMOF) group and a 0.9% saline (placebo) group, with eight rats in each group. Wound excision was performed on the dorsal surface of each rat. In the SMOF group, 1 gm/kg SMOFlipid was dissolved in 3 mL saline as a treatment; in the placebo group, 3 mL saline was prepared as a treatment. The treatments were administered intravenously at an initial rate of 0.2 mL/kg body weight/h immediately after wounding, for 72 h. Blood samples were collected for white blood cell, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 measurements at the baseline and at 1, 6, 12, 24, 48, and 72 h after intervention. Wound areas were measured over a 2-week period after excision, and a histological examination was performed. Compared with the placebo group, SMOFlipid supplementation engendered significant decreases in the wound area on day 3 (78.28 ± 5.25 vs. 105.86 ± 8.89%), day 5 (72.20 ± 4.31 vs. 96.39 ± 4.72%), day 10 (20.78 ± 1.28 vs. 39.80 ± 10.38%), and day 14 (7.56 ± 0.61 vs. 15.10 ± 2.42%). The placebo group had a higher TNF-α level than the SMOF group at 72 h. The IL-10 level was higher in the SMOF group than in the placebo group at 48 h. Histological analysis revealed a higher rate of fibroblast distribution and collagen fiber organization in the SMOF group (P = 0.01). SMOFlipid enriched in ω-3 PUFA accelerates wound healing.

Oil from pumpkin (Cucurbita pepo L.) seeds: evaluation of its functional properties on wound healing in rats.

PubMed

Bardaa, Sana; Ben Halima, Nihed; Aloui, Fatma; Ben Mansour, Riadh; Jabeur, Hazem; Bouaziz, Mohamed; Sahnoun, Zouheir

2016-04-11

Increasing natural drug demand for pharmaceutical uses has encouraged scientifics all over the world to explore medicinal plants recognized as efficient remedies. In this context, extracted oil from pumpkin seeds (Cucurbita pepo L.) is an interesting target, as it is composed with prominent pharmacological properties to possible wound healing treatments. The composition and content of certain bioactive constituents of the cold pressed oil obtained from pumpkin seeds (Cucurbita pepo L.) were analyzed and studied for their wound healing properties. Uniform wounds were induced on the dorsum of 18 rats, randomly divided into three groups. The wounds were photographed, and topically treated with saline solution (control group), 0.13 mg/mm(2) of a reference drug ("Cicaflora cream®"), and 0.52 μl/mm(2) of pumpkin's oil each 2 days until the first group is completely healing and so far biopsies were histologically assessed. The composition and content of tocopherols, fatty acids, and phytosterols were determined. The results showed an excellent quality of pumpkin oil with high content of polyunsaturated fatty acids (Linoleic acid: 50.88 ± 0.106 g/100 g of total fatty acids), tocopherols (280 ppm) and sterols (2086.5 ± 19.092 ppm). High content of these bioactive components were in agreement with an efficient wound healing by the mean of an in vivo study. In fact, morphometric assessment and histological findings revealed healed biopsies from pumpkin oil treated group of rats, unlike untreated group, and a full re-epithelialization with reappearance of skin appendages and well organized collagen fibers without inflammatory cells. This study showed the significance of oil from pumpkin seeds (Cucurbita pepo L.) as a promising drug to healing wounds in animal assays. As a whole, pumpkin's oil would be recommended in the nutritional and medicinal purposes.

Nearly-octave wavelength tuning of a continuous wave fiber laser

PubMed Central

Zhang, Lei; Jiang, Huawei; Yang, Xuezong; Pan, Weiwei; Cui, Shuzhen; Feng, Yan

2017-01-01

The wavelength tunability of conventional fiber lasers are limited by the bandwidth of gain spectrum and the tunability of feedback mechanism. Here a fiber laser which is continuously tunable from 1 to 1.9 μm is reported. It is a random distributed feedback Raman fiber laser, pumped by a tunable Yb doped fiber laser. The ultra-wide wavelength tunability is enabled by the unique property of random distributed feedback Raman fiber laser that both stimulated Raman scattering gain and Rayleigh scattering feedback are available at any wavelength. The dispersion property of the gain fiber is used to control the spectral purity of the laser output. PMID:28198414

Fetal Bovine Collagen Matrix in the Treatment of a Full Thickness Burn Wound: A Case Report With Long-Term Follow-Up.

PubMed

Strong, Amy L; Bennett, Danielle K; Spreen, Elizabeth B; Adhvaryu, Dhaval V; Littleton, Jeffrey C; Mencer, Ernest J

2016-01-01

The treatment of full thickness skin wounds commonly associated with large burns continues to represent a challenging clinical entity. The current treatment for large TBSA burns is split thickness autologous skin grafting; however, this treatment often results in poor textural durability, hypertrophic scarring, and fibrotic contractures. In this case report, we describe our experience and long-term follow-up results after the application of fetal bovine collagen (FBC) matrix (PriMatrix, TEI Biosciences, Boston, MA) to burn wounds clinically assessed as full thickness that healed without the need for subsequent skin grafting. The patient presented with 25% TBSA burns and was debrided and covered with FBC on postburn day 7. By postoperative day 12, the patient had large areas of reepithelialization distributed throughout the wound bed. By postoperative day 26, the patient had significantly more areas of wound closure and was discharged. Reepithelialization and repigmentation continued, and long-term follow-up after 26 months demonstrated complete reepithelialization and nearly complete repigmentation, without the appearance of contractures or hypertrophic scarring. This case report highlights the use of FBC as a scaffold capable of dermal regeneration and spontaneous reepithelialization with an excellent long-term functional and cosmetic outcome.

Fetal Bovine Collagen Matrix in the Treatment of a Full Thickness Burn Wound: A Case Report With Long-Term Follow-Up

PubMed Central

Strong, Amy L.; Bennett, Danielle K.; Spreen, Elizabeth B.; Adhvaryu, Dhaval V.; Littleton, Jeffrey C.

2016-01-01

The treatment of full thickness skin wounds commonly associated with large burns continues to represent a challenging clinical entity. The current treatment for large TBSA burns is split thickness autologous skin grafting; however, this treatment often results in poor textural durability, hypertrophic scarring, and fibrotic contractures. In this case report, we describe our experience and long-term follow-up results after the application of fetal bovine collagen (FBC) matrix (PriMatrix, TEI Biosciences, Boston, MA) to burn wounds clinically assessed as full thickness that healed without the need for subsequent skin grafting. The patient presented with 25% TBSA burns and was debrided and covered with FBC on postburn day 7. By postoperative day 12, the patient had large areas of reepithelialization distributed throughout the wound bed. By postoperative day 26, the patient had significantly more areas of wound closure and was discharged. Reepithelialization and repigmentation continued, and long-term follow-up after 26 months demonstrated complete reepithelialization and nearly complete repigmentation, without the appearance of contractures or hypertrophic scarring. This case report highlights the use of FBC as a scaffold capable of dermal regeneration and spontaneous reepithelialization with an excellent long-term functional and cosmetic outcome. PMID:25494213

Deformation and stress response of composite laminated shells under internal pressure

NASA Technical Reports Server (NTRS)

Yuan, F. G.

1991-01-01

This paper presents a theoretical study of the response of filament wound composite shells under internal pressure. Each layer of the material is generally cylindrically anisotropic. By using cylindrically anisotropic elasticity field equations and Lekhnitskii's stress functions, a system of sixth-order ordinary differential equations is obtained. The general expressions for the stresses and displacements in the laminated composite shells under internal pressure are discussed. Two composite systems, graphite/epoxy and glass/epoxy, are selected to demonstrate the influence of degree of material anisotropy and fiber orientations on the axial and induced twisting deformation. Stress distributions of (45/-45)s symmetric angle-ply fiber-reinforced laminated shells are shown to illustrate the effect of radius-to-thickness ratio.

Interrogation of miniature extrinsic Fabry-Pérot sensor using path matched differential interferometer and phase generated carrier scheme

NASA Astrophysics Data System (ADS)

Wang, Fuyin; Xie, Jiehui; Hu, Zhengliang; Xiong, Shuidong; Luo, Hong; Hu, Yongming

2014-05-01

Study of fiber optic extrinsic Fabry-Pérot sensors utilizing state-of-the-art MEMS technology mostly focus on sensor fabrication for various applications, while the signal interrogation is still insatiable to current application. In this paper, we propose a white light path matched differential interferometer dynamic sensing system utilizing phase generated carrier demodulation scheme. A step motor with a movable mirror and a fiber-wound piezoelectric transducer string are used to act path matching and phase modulation respectively. Experimental results show that the sensing signal could be correctly recovered with low distortion and the phase noise spectrum level is less than -100 dB re. rad/√Hz above 2.5 kHz.

In situ precise electrospinning of medical glue fibers as nonsuture dural repair with high sealing capability and flexibility.

PubMed

Lv, Fu-Yan; Dong, Rui-Hua; Li, Zhao-Jian; Qin, Chong-Chong; Yan, Xu; He, Xiao-Xiao; Zhou, Yu; Yan, Shi-Ying; Long, Yun-Ze

In this work, we propose an in situ precise electrospinning of medical glue fibers onto dural wound for improving sealing capability, avoiding tissue adhesion, and saving time in dural repair. N-octyl-2-cyanoacrylate, a commercial tissue adhesive (medical glue), can be electrospun into ultrathin fibrous film with precise and homogeneous deposition by a gas-assisted electrospinning device. The self-assembled N-octyl-2-cyanoacrylate film shows high compactness and flexibility owing to its fibrous structure. Simulation experiments on egg membranes and goat meninges demonstrated that this technology can repair small membrane defects quickly and efficiently. This method may have potential application in dural repair, for example, working as an effective supplementary technique for conventional dura suture.

The use of negative pressure wound therapy in the treatment of infected wounds. Case studies.

PubMed

Jones, Daniel de Alcântara; Neves Filho, Wilson Vasconcelos; Guimarães, Janice de Souza; Castro, Daniel de Araújo; Ferracini, Antonio Marcos

2016-01-01

To evaluate the results and benefits obtained from the topical use of negative pressure wound therapy (NPWT) in patients with infected wounds. This was a retrospective study of 20 patients (17 males and three females, mean age 42 years) with infected wounds treated using NPWT. The infected wounds were caused by trauma. The treatment system used was VAC. ® (Vacuum Assisted Closure, KCI, San Antonio, United States) applied to the wound in continuous mode from 100 to 125 mmHg. The parameters related to the wounds (location, number of VAC changes, the size of the defects in the soft parts, and the evolution of the state of the wound), length of hospital stay, length of intravenous antibiotic therapy, and complications related to the use of this therapy were evaluated. The mean length of the hospital stay, use of NPWT, and antibacterial therapy were 41 days, 22.5 days, and 20 days respectively. The use of the VAC led to a mean reduction of 29% in the wound area (95.65-68.1 cm 2 ; p  < 0.05). Only one patient did not show any improvement in the final appearance of the wound with complete eradication of the infection. No complication directly caused by NPWT was observed. NPWT stimulates infection-free scar tissue formation in a short time, and is a quick and comfortable alternative to conventional infected wounds treatment methods.

Leptospermum Honey for Wound Care in an Extremely Premature Infant.

PubMed

Esser, Media

2017-02-01

Neonatal wound care is challenging due to the fragility and vulnerable skin structure. Neonates are often left susceptible to the forces of their environment, leaving them open to infection when skin injury occurs. Leptospermum honey has been used successfully in adult patients, with evidence lacking in the neonatal population. This case demonstrates the management of a difficult-to-heal wound in a 23-week gestation infant. Selecting the proper treatment and products for wound healing is challenging, with little evidence-based research available for the treatment of neonatal wounds. Leptospermum honey and other adult-driven dressings have been used for neonatal wound care as well as other adult-driven dressings. This case demonstrates the benefits of Leptospermum honey as an option for neonatal wounds. This case presents the treatment and healing of an extensive wound of a 23-week gestation neonate using a hydrogel product initially and then transitioning to a Leptospermum honey dressing due to suboptimal healing. Results of this treatment included quick healing time, little to no scarring, and no loss of movement or function to the affected extremities. The incorporation of Leptospermum honey for wound care has the potential to promote faster wound healing, with less scarring in the neonatal population. Adult wound care principles have been applied in the face of a weak evidence base relating to neonatal-specific cases. There is a need for continued research related to moist wound healing in the neonatal population, with resulting product and practice recommendations.

40 CFR 414.30 - Applicability; description of the other fibers subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Other Fibers... SIC 2823 cellulosic man-made fibers, except Rayon, and SIC 2824 synthetic organic fibers including...

40 CFR 414.30 - Applicability; description of the other fibers subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Other Fibers... SIC 2823 cellulosic man-made fibers, except Rayon, and SIC 2824 synthetic organic fibers including...

40 CFR 414.30 - Applicability; description of the other fibers subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Other Fibers... SIC 2823 cellulosic man-made fibers, except Rayon, and SIC 2824 synthetic organic fibers including...

40 CFR 414.30 - Applicability; description of the other fibers subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS Other Fibers... SIC 2823 cellulosic man-made fibers, except Rayon, and SIC 2824 synthetic organic fibers including...

Large boron--epoxy filament-wound pressure vessels

NASA Technical Reports Server (NTRS)

Jensen, W. M.; Bailey, R. L.; Knoell, A. C.

1973-01-01

Advanced composite material used to fabricate pressure vessel is prepeg (partially cured) consisting of continuous, parallel boron filaments in epoxy resin matrix arranged to form tape. To fabricate chamber, tape is wound on form which must be removable after composite has been cured. Configuration of boron--epoxy composite pressure vessel was determined by computer program.

Wounded Warriors (AW2), 5th Anniversary Report, 2004-2009

DTIC Science & Technology

2009-01-01

7 History ... Saffrons continue their commitment to the Army and wounded warriors. Recently SSG Saffron and his spouse, Colleen, accepted more than 400 holiday cards...from Harker Heights High School band students for the AW2 Soldiers at Fort Hood, TX, in December 2008. Colleen Saffron , who is extremely involved in

The diversity of myeloid immune cells shaping wound repair and fibrosis in the lung

PubMed Central

Florez‐Sampedro, Laura; Song, Shanshan

2018-01-01

Abstract In healthy circumstances the immune system coordinates tissue repair responses in a tight balance that entails efficient inflammation for removal of potential threats, proper wound closure, and regeneration to regain tissue function. Pathological conditions, continuous exposure to noxious agents, and even ageing can dysregulate immune responses after injury. This dysregulation can lead to a chronic repair mechanism known as fibrosis. Alterations in wound healing can occur in many organs, but our focus lies with the lung as it requires highly regulated immune and repair responses with its continuous exposure to airborne threats. Dysregulated repair responses can lead to pulmonary fibrosis but the exact reason for its development is often not known. Here, we review the diversity of innate immune cells of myeloid origin that are involved in tissue repair and we illustrate how these cell types can contribute to the development of pulmonary fibrosis. Moreover, we briefly discuss the effect of age on innate immune responses and therefore on wound healing and we conclude with the implications of current knowledge on the avenues for future research. PMID:29721324

Fatigue damage development of various CFRP-laminates

NASA Technical Reports Server (NTRS)

Schulte, K.; Baron, CH.

1988-01-01

The chronic strength and fatigue behavior of a woven carbon-fiber reinforced laminate in a balanced eight-shaft satin weave style was compared to nonwoven laminates with an equivalent cross-ply layup. Half the fibers were arranged in the direction of the load and the other half perpendicular to it. Two types of nonwoven laminates consisting of continuous fibers and aligned discontinuous fibers, both produced from carbon fiber prepregs, were studied. The cross-ply laminate with continuous fiber showed the best characteristics with regard to both static strength and fatigue. The similarities and differences in damage mechanisms in the laminates are described.

Use of negative pressure wound therapy in the treatment of neonatal and pediatric wounds: a retrospective examination of clinical outcomes.

PubMed

Baharestani, Mona Mylene

2007-06-01

The clinical effectiveness of negative pressure wound therapy for the management of acute and chronic wounds is well documented in the adult population but information regarding its use in the pediatric population is limited. A retrospective, descriptive study was conducted to examine the clinical outcomes of using negative pressure wound therapy in the treatment of pediatric wounds. The medical records of 24 consecutive pediatric patients receiving negative pressure wound therapy were reviewed. Demographic data, wound etiology, time to closure, closure method, duration of negative pressure wound therapy, complications, dressing change frequency, dressing type used, and pressure settings were analyzed. All categorical variables in the dataset were summarized using frequency (count and percentages) and all continuous variables were summarized using median (minimum, maximum). The 24 pediatric patients (mean age 8.5 years [range 14 days to 18 years old]) had 24 wounds - 12 (50%) were infected at baseline. Sixteen patients had hypoalbuminemia and six had exposed hardware and bone in their wounds. Twenty-two wounds reached full closure in a median time of 10 days (range 2 to 45) following negative pressure wound therapy and flap closure (11), split-thickness skin graft (three), secondary (four), and primary (four) closure. Pressures used in this population ranged from 50 to 125 mm Hg and most wounds were covered with reticulated polyurethane foam. One patient developed a fistula during the course of negative pressure wound therapy. When coupled with appropriate systemic antibiotics, surgical debridement, and medical and nutritional optimization, in this population negative pressure wound therapy resulted in rapid granulation tissue and 92% successful wound closure. Future neonatal and pediatric negative pressure wound therapy usage registries and prospective studies are needed to provide a strong evidence base from which treatment decisions can be made in the management of these challenging cases, especially pertaining to the safety and efficacy of pressure settings, dressings, and interposing contact layer selection.

Mechanical property characterization of polymeric composites reinforced by continuous microfibers

NASA Astrophysics Data System (ADS)

Zubayar, Ali

Innumerable experimental works have been conducted to study the effect of polymerization on the potential properties of the composites. Experimental techniques are employed to understand the effects of various fibers, their volume fractions and matrix properties in polymer composites. However, these experiments require fabrication of various composites which are time consuming and cost prohibitive. Advances in computational micromechanics allow us to study the various polymer based composites by using finite element simulations. The mechanical properties of continuous fiber composite strands are directional. In traditional continuous fiber laminated composites, all fibers lie in the same plane. This provides very desirable increases in the in-plane mechanical properties, but little in the transverse mechanical properties. The effect of different fiber/matrix combinations with various orientations is also available. Overall mechanical properties of different micro continuous fiber reinforced composites with orthogonal geometry are still unavailable in the contemporary research field. In this research, the mechanical properties of advanced polymeric composite reinforced by continuous micro fiber will be characterized based on analytical investigation and FE computational modeling. Initially, we have chosen IM7/PEEK, Carbon Fiber/Nylon 6, and Carbon Fiber/Epoxy as three different case study materials for analysis. To obtain the equivalent properties of the micro-hetero structures, a concept of micro-scale representative volume elements (RVEs) is introduced. Five types of micro scale RVEs (3 square and 2 hexagonal) containing a continuous micro fiber in the polymer matrix were designed. Uniaxial tensile, lateral expansion and transverse shear tests on each RVE were designed and conducted by the finite element computer modeling software ANSYS. The formulae based on elasticity theory were derived for extracting the equivalent mechanical properties (Young's moduli, shear moduli, and Poisson's ratios) from the numerical solutions of the RVEs undergone these three load tests. Validation of the obtained micro-scale mechanical properties will be performed using rule of mixture (ROM), 1st, and 2nd order of the mathematical model and experimental data.

Leaf wound induced ultraweak photon emission is suppressed under anoxic stress: Observations of Spathiphyllum under aerobic and anaerobic conditions using novel in vivo methodology.

PubMed

Oros, Carl L; Alves, Fabio

2018-01-01

Plants have evolved a variety of means to energetically sense and respond to abiotic and biotic environmental stress. Two typical photochemical signaling responses involve the emission of volatile organic compounds and light. The emission of certain leaf wound volatiles and light are mutually dependent upon oxygen which is subsequently required for the wound-induced lipoxygenase reactions that trigger the formation of fatty acids and hydroperoxides; ultimately leading to photon emission by chlorophyll molecules. A low noise photomultiplier with sensitivity in the visible spectrum (300-720 nm) is used to continuously measure long duration ultraweak photon emission of dark-adapting whole Spathiphyllum leaves (in vivo). Leaves were mechanically wounded after two hours of dark adaptation in aerobic and anaerobic conditions. It was found that (1) nitrogen incubation did not affect the pre-wound basal photocounts; (2) wound induced leaf biophoton emission was significantly suppressed when under anoxic stress; and (3) the aerobic wound induced emission spectra observed was > 650 nm, implicating chlorophyll as the likely emitter. Limitations of the PMT photocathode's radiant sensitivity, however, prevented accurate analysis from 700-720 nm. Further examination of leaf wounding profile photon counts revealed that the pre-wounding basal state (aerobic and anoxic), the anoxic wounding state, and the post-wounding aerobic state statistics all approximate a Poisson distribution. It is additionally observed that aerobic wounding induces two distinct exponential decay events. These observations contribute to the body of plant wound-induced luminescence research and provide a novel methodology to measure this phenomenon in vivo.

Medical honey and its role in paediatric patients.

PubMed

Weissenstein, Anne; Luchter, Elisabeth; Bittmann, Stefan

The use of complementary medical treatment in wound management has continued to grow throughout the world. There is a large body of evidence that supports the use of honey as a wound dressing for a wide range of wound types. The authors present an update of present knowledge about honey as a form of complementary medicine in paediatric wound management. The literature cited was found by searching the PubMed, BIOSIS and ISI Web of Science databases for the phrase 'honey and wound'. Papers where honey was used in a mixture with other therapeutic substances were excluded. Randomised controlled trials as well as case studies were taken into consideration. This paper reviews data on the effectiveness of honey in wound healing; 80 citations or references were found that matched the criteria. Furthermore, the wound-healing properties of honey are described and the mechanism of action discussed. The authors' data show that honey induced enhanced epithelialisation, minimised scar formations and had an anti-microbiotic effect. These results should encourage the use of medical honey in the field of paediatrics. It is a safe and natural substance that induces wound healing at a greater rate than conventional methods.

Bilayered nanofibrous 3D hierarchy as skin rudiment by emulsion electrospinning for burn wound management.

PubMed

Pal, Pallabi; Dadhich, Prabhash; Srivas, Pavan Kumar; Das, Bodhisatwa; Maulik, Dhrubajyoti; Dhara, Santanu

2017-08-22

Mimicking skin extracellular matrix hierarchy, the present work aims to develop a bilayer skin graft comprising a porous cotton-wool-like 3D layer with membranous structure of PCL-chitosan nanofibers. Emulsion electrospinning with differential stirring periods of PCL-chitosan emulsion results in development of a bilayer 3D structure with varied morphology. The electrospun membrane has fiber diameter ∼274 nm and pore size ∼1.16 μm while fluffy 3D layer has fiber diameter ∼1.62 μm and pore size ∼62 μm. The 3D layer was further coated with collagen I isolated from Cirrhinus cirrhosus fish scales to improve biofunctionality. Surface coating with collagen I resulted in bundling the fibers together, thereby increasing their average diameter to 2.80 μm and decreasing pore size to ∼45 μm. The architecture and composition of the scaffold promotes efficient cellular activity where interconnected porosity with ECM resembling collagen I coating assists cellular adhesion, infiltration, and proliferation from initial days of fibroblast seeding, while keratinocytes migrate on the surface only without infiltrating in the membranous nanofiber layer. Anatomy of the scaffold arising due to variation in pore size distribution at different layers thereby facilitates compartmentalization and prevents initial cellular transmigration. The scaffold also assists in extracellular matrix protein synthesis and keratinocyte stratification in vitro. Further, the scaffold effectively integrates and attaches with third-degree burn wound margins created in rat models and accelerates healing in comparison to standard Tegaderm dressing™. The bilayer scaffold is thus a promising, readily available, cost-effective, off-the-shelf matrix as a skin substitute.

Conversion of melt-derived microfibrous borate (13-93B3) and silicate (45S5) bioactive glass in a simulated body fluid.

PubMed

Liu, Xin; Rahaman, Mohamed N; Day, Delbert E

2013-03-01

Microfibrous bioactive glasses are showing a considerable capacity to heal soft tissue wounds, but little information is available on the mechanism of healing. In the present study, the conversion of microfibrous borate bioactive glass (diameter = 0.2-5 μm) with the composition designated 13-93B3 (5.5 Na2O, 11.1 K2O, 4.6 MgO, 18.5 CaO, 3.7 P2O5, 56.6 B2O3 wt%) was evaluated in vitro as a function of immersion time in a simulated body fluid (SBF) at 37 °C using structural and chemical techniques. Silicate 45S5glass microfibers (45 SiO2, 24.5 Na2O, 24.5 CaO, 6 P2O5 wt%) were also studied for comparison. Microfibrous 13-93B3 glass degraded almost completely and converted to a calcium phosphate material within 7-14 days in SBF, whereas >85 % of the silica remained in the 45S5 microfibers, forming a silica gel phase. An amorphous calcium phosphate (ACP) product that formed on the 13-93B3 microfibers crystallized at a slower rate to hydroxyapatite (HA) when compared to the ACP that formed on the 45S5 fibers. For immersion times >3 days, the 13-93B3 fibers released a higher concentration of Ca into the SBF than the 45S5 fibers. The fast and more complete degradation, slow crystallization of the ACP product, and higher concentration of dissolved Ca in SBF could contribute to the capacity of the microfibrous borate 13-93B3 glass to heal soft tissue wounds.

Composite skid landing gear design investigation

NASA Astrophysics Data System (ADS)

Shrotri, Kshitij

A Composite Skid Landing Gear Design investigation has been conducted. Limit Drop Test as per Federal Aviation Regulations (FAR) Part 27.725 and Crash test as per MIL STD 1290A (AV) were simulated using ABAQUS to evaluate performance of multiple composite fiber-matrix systems. Load factor developed during multiple landing scenarios and energy dissipated during crash were computed. Strength and stiffness based constraints were imposed. Tsai-Wu and LaRC04 physics based failure criteria were used for limit loads. Hashin's damage initiation criteria with Davila-Camanho's energy based damage evolution damage evolution law were used for crash. Initial results indicate that all single-composite skid landing gear may no be feasible due to strength concerns in the cross member bends. Hybridization of multiple composites with elasto-plastic aluminum 7075 showed proof of strength under limit loads. Laminate tailoring for load factor optimization under limit loads was done by parameterization of a single variable fiber orientation angle for multiple laminate families. Tsai-Wu failure criterion was used to impose strength contraints. A quasi-isotropic N = 4 (pi/4) 48 ply IM7/8552 laminate was shown to be the optimal solution with a load failure will be initiated as matrix cracking under compression and fiber kinking under in-plane shear and longitudinal compression. All failures under limit loads being reported in the metal-composite hybrid joint region, the joint was simulated by adhesive bonding and filament winding, separately. Simply adhesive bonding the metal and composite regions does not meet strength requirements. A filament wound metal-composite joint shows proof of strength. Filament wound bolted metal-composite joint shows proof of strength. Filament wound composite bolted to metal cross member radii is the final joining methodology. Finally, crash analysis was conducted as per requirements from MIL STD 1290A (AV). Crash at 42 ft/sec with 1 design gross weight (DGW) lift was simulated using ABAQUS. Plastic and friction energy dissipation in the reference aluminum skid landing gear was compared with plastic, friction and damage energy dissipation in the hybrid composite design. Damage in composites was modeled as progressive damage with Hashin's damage initiation criteria and an energy based damage evolution law. The latter meets requirements of aircraft kinetic energy dissipation up to 20 ft/sec (67.6 kJ) as per MIL STD 1290A (AV). Weight saving possibility of up to 49% over conventional metal skid landing gear is reported. The final design recommended includes Ke49/PEEK skids, 48 ply IM7/8552 (or IM7/PEEK) cross member tapered beams and Al 7075 cross member bend radii, the latter bolted to the filament wound composite-metal tapered beam. Concerns in composite skid landing gear designs, testing requirements and future opportunities are addressed.

Continuous Fiber Ceramic Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fareed, Ali; Craig, Phillip A.

2002-09-01

Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

Development of a continuous spinning process for producing silicon carbide - silicon nitride precursor fibers

NASA Technical Reports Server (NTRS)

1985-01-01

An apparatus was designed for the continuous production of silicon carbide - silicon nitride precursor fibers. The precursor polymer can be fiberized, crosslined and pyrolyzed. The product is a metallic black fiber with the composition of the type C sub x Si sub y n sub z. Little, other than the tensile strength and modulus of elasticity, is known of the physical properties.

Two-photon confocal microscopy in wound healing

NASA Astrophysics Data System (ADS)

Navarro, Fernando A.; So, Peter T. C.; Driessen, Antoine; Kropf, Nina; Park, Christine S.; Huertas, Juan C.; Lee, Hoon B.; Orgill, Dennis P.

2001-04-01

Advances in histopathology and immunohistochemistry have allowed for precise microanatomic detail of tissues. Two Photon Confocal Microscopy (TPCM) is a new technology useful in non-destructive analysis of tissue. Laser light excites the natural florophores, NAD(P)H and NADP+ and the scattering patterns of the emitted light are analyzed to reconstruct microanatomic features. Guinea pig skin was studied using TPCM and skin preparation methods including chemical depilation and tape striping. Results of TPCM were compared with conventional hematoxylin and eosin microscopy. Two-dimensional images were rendered from the three dimensional reconstructions. Images of deeper layers including basal cells and the dermo-epidermal junction improved after removing the stratum corneum with chemical depilation or tape stripping. TCPM allows good resolution of corneocytes, basal cells and collagen fibers and shows promise as a non-destructive method to study wound healing.

Multiscale Analysis of the Residual Stresses Occurring During Curing and Cooling of Thick-Wall Cross-Ply Filament-Wound Cylinders

NASA Astrophysics Data System (ADS)

Memarianfard, H.; Turusov, R. A.

2017-11-01

A nonlinear numerical multiscale analysis to predict the residual shrinkage and thermal stresses arising during curing and cooling of thickwall cross-ply filament-wound cylinders of a reinforced polymer is performed at macro- and microscales using the representative volume element (RVE) of the composite. The mechanical behavior of the polymeric matrix is described by a nonlinear viscoelastic model with account of chemical shrinkage. The fiber material is considered elastic, isotropic, and temperature-independent. The maximum residual macrostresses arising during manufacture of the cylinders were calculated. The fields of residual microstresses in the RVE in three different zones across the thickness of the cylinders were found. Results of the microscale analysis showed that microstresses in some zones of RVE were several times higher than macrostresses in these areas.

In situ precision electrospinning as an effective delivery technique for cyanoacrylate medical glue with high efficiency and low toxicity.

PubMed

Dong, R H; Qin, C C; Qiu, X; Yan, X; Yu, M; Cui, L; Zhou, Y; Zhang, H D; Jiang, X Y; Long, Y Z

2015-12-14

The side effects or toxicity of cyanoacrylate used in vivo have been argued since its first application in wound closure. We propose an airflow-assisted in situ precision electrospinning apparatus as an applicator and make a detailed comparison with traditional spraying via in vitro and in vivo experiments. This novel method can not only improve operational performance and safety by precisely depositing cyanoacrylate fibers onto a wound, but significantly reduce the dosage of cyanoacrylate by almost 80%. A white blood cell count, liver function test and histological analysis prove that the in situ precision electrospinning applicator produces a better postoperative outcome, e.g., minor hepatocyte injury, moderate inflammation and the significant ability for liver regeneration. This in situ precision electrospinning method may thus dramatically broaden both civilian and military applications of cyanoacrylates.

Protease Inhibition by Oleic Acid Transfer From Chronic Wound Dressings to Albumin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, J. V.; Howley, Phyllis; Davis, Rachel M.

High elastase and cathepsin G activities have been observed in chronic wounds. These levels can inhibit healing through degradation of growth factors, cytokines, and extracellular matrix proteins. Oleic acid (18:1) is a non-toxic elastase inhibitor with some potential for redressing the imbalance of elastase activity found in chronic wounds. Cotton wound dressing material was characterized as a transfer carrier for affinity uptake of 18:1 by albumin under conditions mimicking chronic wounds. 18:1-treated cotton was examined for its ability to bind and release the fatty acid in the presence of albumin. The mechanism of 18:1 uptake from cotton and binding bymore » albumin was examined with both intact dressings and cotton fiber-designed chromatography. Raman spectra of the albumin-18:1 complexes under liquid-liquid equilibrium conditions revealed fully saturated albumin-18:1 complexes with a 1:1 weight ratio of albumin:18:1. Cotton chromatography under liquid-solid equilibrium conditions revealed oleic acid transfer from cotton to albumin at 27 mole equivalents of 18:1 per mole albumin. Cotton was contrasted with hydrogel, and hydrocolloid wound dressing for its comparative ability to lower elastase activity. Each dressing material evaluated was found to release 18:1 in the presence of albumin with significant inhibition of elastase activity. The 18:1-formulated wound dressings lowered elastase activity in a dose dependent manner in the order cotton gauze > hydrogel > hydrocolloid. In contrast the cationic serine protease Cathepsin G was inihibited by 18:1 within a narrow range of 18:1-cotton formulations. Four per cent Albumin solutions were most effective in binding cotton bound-18:1. However, 2% albumin was sufficient to transfer quantities of 18:1 necessary to achieve a significant elastase-lowering effect. Formulations with 128 mg 18:1/g cotton gauze had equivalent elastase lowering with 1 - 4% albumin. 18:1 bound to cotton wound dressings may have promise in the selective lowering of cationic serine protease activity useful in topical application for chronic inflammatory pathogenesis.« less

Flexible matrix composite laminated disk/ring flywheel

NASA Technical Reports Server (NTRS)

Gupta, B. P.; Hannibal, A. J.

1984-01-01

An energy storage flywheel consisting of a quasi-isotropic composite disk overwrapped by a circumferentially wound ring made of carbon fiber and a elastometric matrix is proposed. Through analysis it was demonstrated that with an elastomeric matrix to relieve the radial stresses, a laminated disk/ring flywheel can be designed to store a least 80.3 Wh/kg or about 68% more than previous disk/ring designs. at the same time the simple construction is preserved.

Evaluation of 165 deg F reverse osmosis modules for washwater purification.

NASA Technical Reports Server (NTRS)

Hossain, S.; Goldsmith, R. L.; Tan, M.; Wydeven, T.; Leban, M. I.

1973-01-01

Three membrane systems have been evaluated for concentration at 165 F of wash-water contaminants. Membranes tested are polybenzimidazole (hollow fibers), cellulose acetate blend (spiral wound), and sulfonated polyphenylene oxide (plate-and-frame). Detailed membrane flux and rejection data are presented for 200-hr life tests with synthetic wash water, at two concentrations, and real wash water, at one concentration. Advantages and limitations of the membrane configurations, are discussed.

Effects of microcurrent application alone or in combination with topical Hypericum perforatum L. and Arnica montana L. on surgically induced wound healing in Wistar rats.

PubMed

Castro, Fabiene C B; Magre, Amanda; Cherpinski, Ricardo; Zelante, Paulo M; Neves, Lia M G; Esquisatto, Marcelo A M; Mendonça, Fernanda A S; Santos, Gláucia M T

2012-07-01

This study evaluated the wound healing activity of microcurrent application alone or in combination with topical Hypericum perforatum L. and Arnica montana L. on skin surgical incision surgically induced on the back of Wistar rats. The animals were randomly divided into six groups: (1) no intervention (control group); (2) microcurrent application (10 μA/2 min); (3) topical application of gel containing H. perforatum; (4) topical application of H. perforatum gel and microcurrent (10 μA/2 min); (5) topical application of gel containing A. montana; (6) topical application of A. montana gel and microcurrent (10 μA/2 min). Tissue samples were obtained on the 2nd, 6th and 10th days after injury and submitted to structural and morphometric analysis. Differences in wound healing were observed between treatments when compared to the control group. Microcurrent application alone or combined with H. perforatum gel or A. montana gel exerted significant effects on wound healing in this experimental model in all of the study parameters (P<0.05) when compared to the control group with positive effects seen regarding newly formed tissue, number of newly formed blood vessels and percentage of mature collagen fibers. The morphometric data confirmed the structural findings. In conclusion, application of H. perforatum or A. montana was effective on experimental wound healing when compared to control, but significant differences in the parameters studied were only observed when these treatments were combined with microcurrent application. Copyright © 2012 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Medical applications of VIS/NIR spectroscopy of human tissue surfaces by a novel portable instrumentation

NASA Astrophysics Data System (ADS)

Otto, Thomas; Stock, Volker; Schmidt, Wolf-Dieter; Liebold, Kristin; Fassler, Dieter; Wollina, Uwe; Fritzsch, Uwe; Gessner, Thomas

2001-11-01

In medical diagnostics, non invasive optical techniques will become common at a variety of applications because they contribute to objectivity and precision. The spectral properties of human tissue are an important field of interest. They offer opportunities of detection of skin diseases and of evaluation of chronic wounds. In the visible range, the hemoglobin absorption corresponds to blood microcirculation and the melanin absorption to the skin-type. Two types of diode-array equipment will be described: a combined VIS-NIR spectrometer system from J&M Aalen/Germany (400 nm to 1600 nm) and a stand-alone spectrometer from COLOUR CONTROL Farbmesstechnik Chemnitz/Germany (400 nm to 1000 nm). Non-contacting sensing is essential for investigating chronic wounds (no disturbances of blood microcirculation by contact pressure). The spectroscopic VIS-NIR readings of chronic wounds mainly depend on the absorption of hemoglobin and water. Multivariate analysis was applied for an objective spectral classification of eight different wound scores. Some results regarding spectral measurements of wounds and skin will be discussed. The spectrometer of COLOUR CONTROL was tested in dental surgery. To select dentures, its color has to be determined exactly to meet beauty culture demands. Color determination by dentist is not sufficient enough because of possible metameric effects of illumination. Results of spectral evaluation of denture material and human teeth will be given. Medical examination requires portable and ease equipment suitable for precise measurements. This is solved by a modular measurement system comprising microcomputer, display, light source, fiber probe, and diode-array spectrometer. It is efficient to process primary spectral data to appropriate medical interpretations.

A Rat Model for Muscle Regeneration in the Soft Palate

PubMed Central

Carvajal Monroy, Paola L.; Grefte, Sander; Kuijpers-Jagtman, Anne M.; Helmich, Maria P. A. C.; Ulrich, Dietmar J. O.; Von den Hoff, Johannes W.; Wagener, Frank A. D. T. G.

2013-01-01

Background Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. Despite successful surgical repositioning of the muscles, optimal function is often not achieved. Scar formation and defective regeneration may hamper the functional recovery of the muscles after cleft palate repair. Therefore, the aim of this study is to investigate the anatomy and histology of the soft palate in rats, and to establish an in vivo model for muscle regeneration after surgical injury. Methods Fourteen adult male Sprague Dawley rats were divided into four groups. Groups 1 (n = 4) and 2 (n = 2) were used to investigate the anatomy and histology of the soft palate, respectively. Group 3 (n = 6) was used for surgical wounding of the soft palate, and group 4 (n = 2) was used as unwounded control group. The wounds (1 mm) were evaluated by (immuno)histochemistry (AZAN staining, Pax7, MyoD, MyoG, MyHC, and ASMA) after 7 days. Results The present study shows that the anatomy and histology of the soft palate muscles of the rat is largely comparable with that in humans. All wounds showed clinical evidence of healing after 7 days. AZAN staining demonstrated extensive collagen deposition in the wound area, and initial regeneration of muscle fibers and salivary glands. Proliferating and differentiating satellite cells were identified in the wound area by antibody staining. Conclusions This model is the first, suitable for studying muscle regeneration in the rat soft palate, and allows the development of novel adjuvant strategies to promote muscle regeneration after cleft palate surgery. PMID:23554995

A rat model for muscle regeneration in the soft palate.

PubMed

Carvajal Monroy, Paola L; Grefte, Sander; Kuijpers-Jagtman, Anne M; Helmich, Maria P A C; Ulrich, Dietmar J O; Von den Hoff, Johannes W; Wagener, Frank A D T G

2013-01-01

Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. Despite successful surgical repositioning of the muscles, optimal function is often not achieved. Scar formation and defective regeneration may hamper the functional recovery of the muscles after cleft palate repair. Therefore, the aim of this study is to investigate the anatomy and histology of the soft palate in rats, and to establish an in vivo model for muscle regeneration after surgical injury. Fourteen adult male Sprague Dawley rats were divided into four groups. Groups 1 (n = 4) and 2 (n = 2) were used to investigate the anatomy and histology of the soft palate, respectively. Group 3 (n = 6) was used for surgical wounding of the soft palate, and group 4 (n = 2) was used as unwounded control group. The wounds (1 mm) were evaluated by (immuno)histochemistry (AZAN staining, Pax7, MyoD, MyoG, MyHC, and ASMA) after 7 days. The present study shows that the anatomy and histology of the soft palate muscles of the rat is largely comparable with that in humans. All wounds showed clinical evidence of healing after 7 days. AZAN staining demonstrated extensive collagen deposition in the wound area, and initial regeneration of muscle fibers and salivary glands. Proliferating and differentiating satellite cells were identified in the wound area by antibody staining. This model is the first, suitable for studying muscle regeneration in the rat soft palate, and allows the development of novel adjuvant strategies to promote muscle regeneration after cleft palate surgery.

Synthesis, characterization, and antimicrobial properties of novel double layer nanocomposite electrospun fibers for wound dressing applications

PubMed Central

Hassiba, Alaa J; El Zowalaty, Mohamed E; Webster, Thomas J; Abdullah, Aboubakr M; Nasrallah, Gheyath K; Khalil, Khalil Abdelrazek; Luyt, Adriaan S; Elzatahry, Ahmed A

2017-01-01

Herein, novel hybrid nanomaterials were developed for wound dressing applications with antimicrobial properties. Electrospinning was used to fabricate a double layer nanocomposite nanofibrous mat consisting of an upper layer of poly(vinyl alcohol) and chitosan loaded with silver nanoparticles (AgNPs) and a lower layer of polyethylene oxide (PEO) or polyvinylpyrrolidone (PVP) nanofibers loaded with chlorhexidine (as an antiseptic). The top layer containing AgNPs, whose purpose was to protect the wound site against environmental germ invasion, was prepared by reducing silver nitrate to its nanoparticulate form through interaction with chitosan. The lower layer, which would be in direct contact with the injured site, contained the antibiotic drug needed to avoid wound infections which would otherwise interfere with the healing process. Initially, the upper layer was electrospun, followed sequentially by electrospinning the second layer, creating a bilayer nanofibrous mat. The morphology of the nanofibrous mats was studied by scanning electron microscopy and transmission electron microscopy, showing successful nanofiber production. X-ray diffraction confirmed the reduction of silver nitrate to AgNPs. Fourier transform infrared spectroscopy showed a successful incorporation of the material used in the produced nanofibrous mats. Thermal studies carried out by thermogravimetric analysis indicated that the PVP–drug-loaded layer had the highest thermal stability in comparison to other fabricated nanofibrous mats. Antimicrobial activities of the as-synthesized nanofibrous mats against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were determined using disk diffusion method. The results indicated that the PEO–drug-loaded mat had the highest antibacterial activity, warranting further attention for numerous wound-healing applications. PMID:28356737

The effect of different biologic and biosynthetic wound covers on keratinocyte growth, stratification and differentiation in vitro

PubMed Central

Mestak, Ondrej

2014-01-01

The purpose of this study was to compare, by means of in vitro cultivation technique, five marketed brands of wound covers used in the treatment of burns and other skin defects (Biobrane®, Suprathel®, Veloderm®, Xe-Derma®, and Xenoderm®) for their ability to stimulate the keratinocyte growth, stratification, and differentiation. In three independent experiments, human keratinocytes were grown on the tested covers in organotypic cultures by the 3T3 feeder layer technique. Vertical paraffin sections of the wound covers with keratinocytes were processed using hematoxylin–eosin staining and immunostaining for involucrin. Keratinocyte populations on the dressings were assessed for (1) number of keratinocyte strata (primary variable), (2) quantitative growth, (3) thickness of the keratinocyte layer, and (4) cell differentiation. The Xe-Derma wound cover provided the best support to keratinocyte proliferation and stratification, with the number of keratinocyte strata significantly (p < 0.05) higher in comparison to all products studied, except Xenoderm. However, in contrast to Xe-Derma, Xenoderm did not significantly differ from the other dressings. The results of this in vitro study show that the brands based on porcine dermal matrix possess the strongest effect on keratinocyte proliferation and stratification. The distinctive position of Xe-Derma may be related to its composition, where natural dermal fibers form a smooth surface, similar to the basement membrane. Furthermore, the results indicate that in vitro evaluation of effects on epithelial growth may accelerate the development of new bio-engineering-based wound covers. PMID:25383177

Effects of neodymium-yttrium-aluminum garnet (Nd:YAG) pulsed high-intensity laser therapy on full thickness wound healing in an experimental animal model.

PubMed

Hong, Seung Eun; Hong, Mi Ki; Kang, So Ra; Young Park, Bo

2016-12-01

Wound healing can be aided by the use of low- and medium-intensity lasers. The use of pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) high-intensity laser therapy (HILT) with a 1064-nm wavelength laser provides deeper and more efficient penetration into tissue as it is being less absorbed by chromophores in tissue, e.g., hemoglobin, melanin, and water, thereby enhancing the wound-healing process. In this study, we examined the effect of HILT on wound healing with a Q-switched pulsed Nd:YAG laser in an animal model. Sixty SKH1 hairless male mice (seven weeks old) were randomly divided into four groups according to the amount of laser fluence: control, group 1 (0.8 J/cm 2 ), group 2 (1.6 J/cm 2 ), and group 3 (2.0 J/cm 2 ). Laser treatment was provided to groups 1, 2, and 3 with a 1064-nm Q-switched Nd:YAG laser. Histological analysis was performed with hematoxylin and eosin staining, Masson's Trichrome staining, and Ki-67 staining. Statistically significant increases in the accumulation of collagen fibers, thickness of granulation tissue, and numbers of fibroblasts were observed in group 2 (treated with 1.6 J/cm 2 ) as compared with the control (no laser treatment), group 1 (treated with 0.8 J/cm 2 ), and group 3 (treated with 2.0 J/cm 2 ). Nd:YAG HILT stimulated fibroblast proliferation and increased extracellular matrix production. We expect that this therapy could accelerate the wound-healing process.

Development of a silicone hollow fiber membrane oxygenator for ECMO application.

PubMed

Yamane, S; Ohashi, Y; Sueoka, A; Sato, K; Kuwana, J; Nosé, Y

1998-01-01

A new silicone hollow fiber membrane oxygenator for extracorporeal membrane oxygenation (ECMO) was developed using an ultrathin silicone hollow fiber, with a 300 microm outer diameter and a wall thickness of 50 microm. The hollow fibers were mechanically cross-wound on the flow distributor to achieve equal distribution of blood flow without changing the fiber shape. The housing, made of silicone coated acryl, was 236 mm long with an inner diameter of 60 mm. The surface area was 1.0 m2 for prototype 211, and 1.1 m2 for prototype 209. The silicone fiber length was 150 mm, and the silicone membrane packing density was 43% for prototype 211 and 36% for prototype 209. Prototype 211 has a priming volume of 208 ml, and prototype 209 has a priming volume of 228 ml. The prototype 211 oxygenator demonstrates a gas transfer rate of 120 +/- 5 ml/min (mean +/- SD) for O2 and 67 +/- 12 ml/min for CO2 under 2 L of blood flow and 4 L of O2 gas flow. Prototype 209 produced the same values. The blood side pressure drop was low compared with the silicone sheet oxygenator (Avecor, 1500ECMO). These results showed that this new oxygenator for ECMO had efficiency similar to the silicone sheet oxygenator that has a 50% larger surface area. These results suggest that the new generation oxygenator using an ultrathin silicone hollow fiber possesses sufficient gas transfer performance for long-term extracorporeal lung support.

Preparation of SMART wound dressings based on colloidal microgels and textile fibres

NASA Astrophysics Data System (ADS)

Cornelius, Victoria J.; Majcen, Natasa; Snowden, Martin J.; Mitchell, John C.; Voncina, Bojana

2007-01-01

Wound dressings and other types of wound healing technologies are experiencing fast-paced development and rapid growth. As the population ages, demand will continue to rise for advanced dressings used to treat chronic wounds, such as pressure ulcers, venous stasis ulcers, and diabetic ulcers. Moist wound dressings, which facilitate natural wound healing in a cost-effective manner, will be increasingly important. In commercially available hydrogel / gauze wound dressings the gel swells to adsorb wound excreta and provide an efficient non adhesive particle barrier. An alternative to hydrogels are microgels. Essentially discrete colloidal gel particles, as a result of their very high surface area to volume ratio compared to bulk gels, they have a much faster response to external stimuli such as temperature or pH. In response to either an increase or decrease in solvent quality these porous networks shrink and swell reversibly. When swollen the interstitial regions within the polymer matrix are available for further chemistry; such as the incorporation of small molecules. The reversible shrinking and swelling as a function of external stimuli provides a novel drug release system. As the environmental conditions of a wound change over its lifetime, tending to increase in pH if there is an infection combining these discrete polymeric particles with a substrate such as cotton, results in a smart wound dressing.

Artefact in forensic medicine: non-missile penetrating injury.

PubMed

Patel, F

1994-12-01

Gunshot wounds are well characterised in forensic textbooks and atypical or unusual ballistic characteristics feature regularly in forensic literature. Forensic practitioners receive continuing education in recognising a variety of gunshot wounds which are created by bullet missiles. Awareness of a non-missile penetrating injury mimicking a gunshot wound is also relevant to forensic medical examiners or others who are likely to attend a scene of death. In this case, which involved self-stabbing with a metal nail, a homicidal firearm death investigation was instigated because of a misinterpretation by crime scene investigators.

Scientific and clinical support for the use of dehydrated amniotic membrane in wound management.

PubMed

Fetterolf, Donald E; Snyder, Robert J

2012-10-01

 Amniotic membrane has been employed in the treatment of wounds for almost 100 years, beginning with early application of natural amniotic membrane obtained from labor and delivery to various types of burns and wounds. Amniotic membrane is rich in collagen and various growth factors that support the healing process to both improve wound closure and reduce scar formation. Unique properties of the material include the lack of immunologic markers, conferring an "immune privileged" status on the allografts; antibacterial properties; and the ability to reduce pain on application. The resurgence of interest in the use of amniotic membrane in a number of applications, including wound treatment, has occurred following improved techniques for preserving the natural membrane. Recently, techniques have been developed to dehydrate the material while preserving many of these wound-healing attributes, to produce a temperature-stable allograft. Future research will continue to yield more information on the unique properties of the amniotic membrane allografts. .

Current Advancements and Strategies in Tissue Engineering for Wound Healing: A Comprehensive Review.

PubMed

Ho, Jasmine; Walsh, Claire; Yue, Dominic; Dardik, Alan; Cheema, Umber

2017-06-01

Significance: With an aging population leading to an increase in diabetes and associated cutaneous wounds, there is a pressing clinical need to improve wound-healing therapies. Recent Advances: Tissue engineering approaches for wound healing and skin regeneration have been developed over the past few decades. A review of current literature has identified common themes and strategies that are proving successful within the field: The delivery of cells, mainly mesenchymal stem cells, within scaffolds of the native matrix is one such strategy. We overview these approaches and give insights into mechanisms that aid wound healing in different clinical scenarios. Critical Issues: We discuss the importance of the biomimetic niche, and how recapitulating elements of the native microenvironment of cells can help direct cell behavior and fate. Future Directions: It is crucial that during the continued development of tissue engineering in wound repair, there is close collaboration between tissue engineers and clinicians to maintain the translational efficacy of this approach.

Current Advancements and Strategies in Tissue Engineering for Wound Healing: A Comprehensive Review

PubMed Central

Ho, Jasmine; Walsh, Claire; Yue, Dominic; Dardik, Alan; Cheema, Umber

2017-01-01

Significance: With an aging population leading to an increase in diabetes and associated cutaneous wounds, there is a pressing clinical need to improve wound-healing therapies. Recent Advances: Tissue engineering approaches for wound healing and skin regeneration have been developed over the past few decades. A review of current literature has identified common themes and strategies that are proving successful within the field: The delivery of cells, mainly mesenchymal stem cells, within scaffolds of the native matrix is one such strategy. We overview these approaches and give insights into mechanisms that aid wound healing in different clinical scenarios. Critical Issues: We discuss the importance of the biomimetic niche, and how recapitulating elements of the native microenvironment of cells can help direct cell behavior and fate. Future Directions: It is crucial that during the continued development of tissue engineering in wound repair, there is close collaboration between tissue engineers and clinicians to maintain the translational efficacy of this approach. PMID:28616360

Effects of different doses of tramadol added to levobupivacaine in continuous wound infusion for postoperative pain treatment following cesarean section.

PubMed

Ekmekçi, Perihan; Çağlar, Gamze S; Yilmaz, Hakan; Kazbek, Baturay K; Gursoy, Asli Yarci; Kiseli, Mine; Tüzüner, Filiz

2017-02-01

The aim of this study was to compare the effects of two different doses of tramadol added to levobupivacaine as continuous wound infusion, on VAS scores following cesarean section. The study was conducted in an University Hospital and was approved by the Local Ethical Committee. Sixty-five ASA I-II parturients, between 18 and 45 years were enrolled. The participants were randomized to three groups. Group T1 (n = 21) was given the study solution consisting of levobupivacaine 0.25% + tramadol 1 mg/kg. Group T2 (n = 21) was given levobupivacaine 0.25% + tramadol 2 mg/kg and Group L (n = 21) was given levobupivacaine 0.25%, subcutaneously, alone. Each patient who delivered by cesarean section was applied a triple orifice epidural catheter above rectus fascia for continious wound infiltration. VAS at rest and with 20 degrees leg lift, time to first additional analgesic, total additional analgesic consumption, side effects, and sedation scores were recorded. There were no statistically significant differences among groups, concerning VAS scores at rest and VAS scores at leg lift. Total amount of additional analgesics and sedation scores were also similar for three groups. Different doses of tramadol as adjunct to local anesthetics in continuous wound infiltration following cesarean section do not seem to provide superior analgesia.

In vitro stimulation of vascular endothelial growth factor by borate-based glass fibers under dynamic flow conditions.

PubMed

Chen, Sisi; Yang, Qingbo; Brow, Richard K; Liu, Kun; Brow, Katherine A; Ma, Yinfa; Shi, Honglan

2017-04-01

Bioactive borate glass has been recognized to have both hard and soft tissue repair and regeneration capabilities through stimulating both osteogenesis and angiogenesis. However, the underlying biochemical and cellular mechanisms remain unclear. In this study, dynamic flow culturing modules were designed to simulate the micro-environment near the vascular depletion and hyperplasia area in wound-healing regions, thus to better investigate the mechanisms underlying the biocompatibility and functionality of borate-based glass materials. Glass fibers were dosed either upstream or in contact with the pre-seeded cells in the dynamic flow module. Two types of borate glasses, doped with (1605) or without (13-93B3) CuO and ZnO, were studied along with the silicate-based glass, 45S5. Substantial fiber dissolution in cell culture medium was observed, leading to the release of ions (boron, sodium and potassium) and the deposition of a calcium phosphate phase. Different levels of vascular endothelial growth factor secretion were observed from cells exposed to these three glass fibers, and the copper/zinc containing borate 1605 fibers exhibited the most positive influence. These results indicate that dynamic studies of in vitro bioactivity provide useful information to understand the in vivo response to bioactive borate glasses. Copyright © 2016 Elsevier B.V. All rights reserved.

Continuous Aspirin Use Does Not Increase Bleeding Risk of Split-Thickness Skin Transplantation Repair to Chronic Wounds.

PubMed

Sun, Yanwei; Wang, Yibing; Li, Liang; Zhang, Zheng; Wang, Ning; Wu, Dan

Discontinuation of aspirin therapy before cutaneous surgery may cause serious complications. The aim of this prospective study was to evaluate the bleeding risk of split-thickness skin transplantation repair to chronic wounds in patients on aspirin therapy. A total of 97 patients who underwent split-thickness skin transplantation surgery of chronic wounds during a 2-year period were enrolled. They were categorized on the basis of aspirin therapies. The primary outcome was postoperative bleeding and bleeding complications. Univariate analysis was performed to examine the association between aspirin and bleeding complications. Among the 26 patients taking aspirin continuously in group A, there were 5 bleeding complications (19.23%). Among the 55 nonusers in group B, there were 10 bleeding complications (18.18%). Among the 16 discontinuous patients in group C, there were 3 bleeding complications (18.75%). No statistical differences were found among the groups ( P = .956). Univariate analysis showed that continuous aspirin use was not significantly associated with bleeding complications (odds ratio, 0.933; 95% confidence interval, 0.283-3.074; P = .910 in the aspirin and control groups) and that discontinuous aspirin use was not significantly associated with bleeding complications (odds ratio, 0.963; 95% confidence interval, 0.230-4.025; P = .959 in the aspirin and control groups; odds ratio, 0.969; 95% confidence interval, 0.198-4.752; P = .969 in the aspirin and discontinuous groups). Continuous aspirin use does not produce an additional bleeding risk in patients who undergo split-thickness skin transplantation repair of chronic wounds.

Carbon Fiber Reinforced Carbon Composite Valve for an Internal Combustion Engine

NASA Technical Reports Server (NTRS)

Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor)

1999-01-01

A carbon fiber reinforced carbon composite valve for internal combustion engines and the like formed of continuous carbon fibers throughout the valve's stem and head is disclosed. The valve includes braided carbon fiber material over axially aligned unidirectional carbon fibers forming a valve stem; the braided and unidirectional carbon fibers being broomed out at one end of the valve stem forming the shape of the valve head; the valve-shaped structure being densified and rigidized with a matrix of carbon containing discontinuous carbon fibers: and the finished valve being treated to resist oxidation. Also disclosed is a carbon matrix plug containing continuous and discontinuous carbon fibers and forming a net-shape valve head acting as a mandrel over which the unidirectional and braided carbon fibers are formed according to textile processes. Also disclosed are various preform valves and processes for making finished and preform carbon fiber reinforced carbon composite valves.

43 CFR 2568.60 - May the personal representatives of eligible deceased veterans apply on their behalf?

Code of Federal Regulations, 2013 CFR

2013-10-01

... Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) ALASKA OCCUPANCY AND USE Alaska Native Allotments For Certain Veterans Personal... wounded in action and later died as a direct consequence of that wound, as determined and certified by the...

43 CFR 2568.60 - May the personal representatives of eligible deceased veterans apply on their behalf?

Code of Federal Regulations, 2014 CFR

2014-10-01

... Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) ALASKA OCCUPANCY AND USE Alaska Native Allotments For Certain Veterans Personal... wounded in action and later died as a direct consequence of that wound, as determined and certified by the...

43 CFR 2568.60 - May the personal representatives of eligible deceased veterans apply on their behalf?

Code of Federal Regulations, 2011 CFR

2011-10-01

... Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) ALASKA OCCUPANCY AND USE Alaska Native Allotments For Certain Veterans Personal... wounded in action and later died as a direct consequence of that wound, as determined and certified by the...

43 CFR 2568.60 - May the personal representatives of eligible deceased veterans apply on their behalf?

Code of Federal Regulations, 2012 CFR

2012-10-01

... Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) ALASKA OCCUPANCY AND USE Alaska Native Allotments For Certain Veterans Personal... wounded in action and later died as a direct consequence of that wound, as determined and certified by the...

Silence, Words that Wound and Sexual Identity: A Conversation with Applebaum

ERIC Educational Resources Information Center

Jackson, Liz

2008-01-01

In this paper, I continue a conversation initiated by Barbara Applebaum on how to manage irreconcilable difference, harmful language or "words that wound" and various implications of power in the classroom. Referencing emerging works on the nature of speech and silence, classroom power and queer identity, I pose three questions to Applebaum in…

21 CFR 878.4683 - Non-Powered suction apparatus device intended for negative pressure wound therapy.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Non-Powered suction apparatus device intended for negative pressure wound therapy. 878.4683 Section 878.4683 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

21 CFR 878.4683 - Non-Powered suction apparatus device intended for negative pressure wound therapy.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Non-Powered suction apparatus device intended for negative pressure wound therapy. 878.4683 Section 878.4683 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

21 CFR 878.4683 - Non-Powered suction apparatus device intended for negative pressure wound therapy.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Non-Powered suction apparatus device intended for negative pressure wound therapy. 878.4683 Section 878.4683 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

A Prospective, Randomized, Double-Blind Multicenter Study Comparing Continuous Diffusion of Oxygen Therapy to Sham Therapy in the Treatment of Diabetic Foot Ulcers.

PubMed

Niederauer, Mark Q; Michalek, Joel E; Armstrong, David G

2017-09-01

Over the past generation, preclinical data have suggested that there is a potential physiologic benefit to applying oxygen topically to wounds. However, we are unaware of any studies in the literature that have robustly assessed whether this would lead to a higher proportion of healing in similarly treated people without oxygen. Therefore, the purpose of this study was to assess this in people being treated for chronic diabetic foot ulcers (DFUs). We enrolled and randomized 100 subjects with DFUs (79% male, aged 58.3 ± 12.1 years) to receive either active continuous diffusion of oxygen (CDO) therapy using an active CDO device, or an otherwise fully operational sham device that provided moist wound therapy (MWT) without delivering oxygen. Patients were followed until closure or 12 weeks, whichever was sooner. Patients, treating physicians and independent evaluators were blinded to the study arm. All patients received identical offloading, dressings and follow-up. There were no significant differences in assessed descriptive characteristics between the treatment arms ( P > .05 for all). A significantly higher proportion of people healed in the active arm compared to sham (46% vs 22%, P = .02). This relative effect became greater in more chronic wounds (42.5% vs 13.5%, P = .006). Patients randomized to the active device experienced significantly faster rates of closure relative to the sham ( P < .001). The results of this study suggest that continuously diffused oxygen over a wound leads to significantly higher rates of closure, and faster time to closure, compared to similarly treated patients receiving standard therapy coupled with a sham device. Furthermore, the relative efficacy appears to improve the more the therapy may be needed (more chronic and larger wounds).

[Chronic wounds as a public health problem].

PubMed

Situm, Mirna; Kolić, Maja; Redzepi, Gzim; Antolić, Slavko

2014-10-01

Chronic wounds represent a significant burden to patients, health care professionals and the entire health care system. Regarding the healing process, wounds can be classified as acute or chronic wounds. A wound is considered chronic if healing does not occur within the expected period according to the wound etiology and localization. Chronic wounds can be classified as typical and atypical. The majority of wounds (95 percent) are typical ones, which include ischemic, neurotrophic and hypostatic ulcers and two separate entities: diabetic foot and decubital ulcers. Eighty percent of chronic wounds localized on lower leg are the result of chronic venous insufficiency, in 5-10 percent the cause is of arterial etiology, whereas the rest are mostly neuropathic ulcers. Chronic wounds significantly decrease the quality of life of patients by requiring continuous topical treatment, causing immobility and pain in a high percentage of patients. Chronic wounds affect elderly population. Chronic leg ulcers affect 0.6-3 percent of those aged over 60, increasing to over 5 percent of those aged over 80. Emergence of chronic wounds is a substantial socioeconomic problem as 1-2 percent of western population will suffer from it. This estimate is expected to rise due to the increasing proportion of elderly population along with the diabetic and obesity epidemic. It has been proved that chronic wounds account for the large proportion of costs in the health care system, even in rich societies. Socioeconomically, the management of chronic wounds reaches a total of 2-4 percent of the health budget in western countries. Treatment costs for some other diseases are not irrelevant, nor are the method and materials used for treating these wounds. Considering etiologic factors, a chronic wound demands a multidisciplinary approach with great efforts of health care professionals to treat it more efficiently, more simply and more painlessly for the patient, as well as more inexpensively for health care funds.

Improvement of wound healing by regulated oxygen-enriched negative pressure-assisted wound therapy in a rabbit model.

PubMed

Li, Y Z; Hu, X D; Lai, X M; Li, Y F; Lei, Y

2018-01-01

Development of drug therapies and other techniques for wound care have resulted in significant improvement of the cure rate and shortening of the healing time for wounds. A modified technique of regulated oxygen-enriched negative pressure-assisted wound therapy (RO-NPT) has been reported. To evaluate the efficacy and impact of RO-NPT on wound recovery and inflammation. Infected wounds were established on 40 adult female white rabbits, which were then randomized to one of four groups: O 2 group, regulated negative pressure-assisted wound therapy (RNPT) group, regulated oxygen-enriched negative pressure-assisted wound therapy (RO-NPT) group and healthy control (HC) group. Each day, the O 2 group was treated with a constant oxygen supply (1 L/min) to the wound, while the RNPT group was treated with continuous regulated negative pressure (70 ± 5 mmHg) and the RNPT + O 2 group was treated with both. The HC group was treated with gauze dressing alone, which was changed every day. Leucocyte count, colony count and wound-healing rate were calculated. Levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β and IL-8 were evaluated by ELISA. RO-RNPT significantly decreased bacterial count and TNF-α level, and increased the wound-healing rate. IL-1β, IL-8 and leucocyte count had a tendency to increase in the early phase of inflammation and a tendency to decrease in the later phase of inflammation in the RO-RNPT group. RO-NPT therapy assisted wound recovery and inflammation control compared with the RNPT and oxygen-enriched therapies. RO-NPT therapy also increased levels of IL-1β and IL-8 and attenuated expression of TNF-α in the early phase of inflammation. © 2017 British Association of Dermatologists.

An mHealth App for Decision-Making Support in Wound Dressing Selection (WounDS): Protocol for a User-Centered Feasibility Study.

PubMed

Jordan, Scott; McSwiggan, Jane; Parker, Joanne; Halas, Gayle A; Friesen, Marcia

2018-04-24

Primary care health professionals, especially family physicians, see a variety of wounds, and yet-despite the frequency of providing wound care-many family physicians do not feel confident in wound care management. This is partly due to a lack of formal wound education in Family Medicine programs. While there are numerous electronic wound care resources available in the UK and North America, none were identified that address the specific need in supporting clinical decision-making in wound dressing selection. At the same time, healthcare providers are increasingly using technology in personal and professional contexts, and a logical extension is to use technology for knowledge translation strategies. This work developed a prototype mobile health software application named WounDS, designed to support clinical decision-making in selecting wound dressings. This article presents the development and evaluation plan for the WounDS app. WounDS has been developed on the iOS platform. The primary specification included ease of use, in that one of the primary influences in user adoption would be the ability to receive a wound dressing recommendation in under 30 seconds and under 5 taps on the screen. The WounDS app guides users through a series of binary decisions for assessing the wound and provides a wound dressing recommendation. The selection algorithm is based in best practices using the Wound Bed Preparation Paradigm. Current work is underway to examine the implementation needs for WounDS to be most effectively utilized and to pilot test its feasibility and use in clinical care. Data will be collected through user trials, focus groups, and user metadata will be collected within the app. Optimizing these preconditions will enable a subsequent phase of study to determine effects on clinical decision-making and clinical outcomes. WounDS is designed for knowledge translation, use of technology in clinical decision-making, and continuity of care. The benefits of WounDS include the potential to improve healthcare providers' competency in wound management and to improve wound healing through better alignment with evidence-based best practices in wound dressing selection, consistency in care from primary to community care, and subsequent downstream impacts in quality of life for patients. ©Scott Jordan, Jane McSwiggan, Joanne Parker, Gayle A. Halas, Marcia Friesen. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 24.04.2018.

Comparison of Neurovascular Characteristics of Facial Skin in Patients After Primary and Revision Rhytidectomies.

PubMed

Ardeshirpour, Farhad; Hurliman, Elisabeth; Wendelschafer-Crabb, Gwen; McAdams, Brian; Hilger, Peter A; Kennedy, William R; Lassig, Amy Anne D; Brenner, Michael J

2017-09-01

Wound healing influences both the cosmetic and functional outcomes of facial surgery. Study of cutaneous innervation may afford insight into patients' preoperative wound healing potential and aid in their selection of appropriate surgical procedures. To present the quantitative and qualitative differences of epidermal nerve fibers (ENFs), neurotransmitters, vasculature, and mast cells in facial skin among patients after primary and revision rhytidectomies. This pilot study collected cutaneous specimens from 8 female patients aged 42 to 66 years who underwent primary rhytidectomy (n = 5) and revision rhytidectomy (n = 3) at Centennial Lakes Surgery Center, Edina, Minnesota, from July 2010 to March 2014. Tissue was processed for confocal/epifluorescence microscopy and indirect immunofluorescent localization of several neural and tissue antigens as well as basement membrane and mast cell markers. Primary rhytidectomy vs revision rhytidectomy with selection of a small area of redundant, otherwise disposed of tissue anterior to the tragus for ENF study. Demographic characteristics included smoking status; 10-point rating scales for facial sensation, pain, and paresthesias; and confocal/epifluorescence microscopy to quantify ENFs, neurotransmitters, vasculature, and mast cells. Patients in the primary rhytidectomy group had a mean (SD) of 54.4 (31.6) ENFs/mm (range, 14.2-99.2 ENFs/mm), and those in the revision rhytidectomy group had a mean (SD) of 18.6 (5.8) ENFs/mm (range, 13.8-25.0 ENFs/mm). A patient in the primary rhytidectomy group was a 25-pack-year smoker and had 14.2 ENFs/mm, the lowest in both groups. In addition to these structural neural changes, functional neural changes in revision rhytidectomy samples included qualitative changes in normal neural antigen prevalence (substance P, calcitonin gene-related peptide, and vasoactive intestinal peptide). Capillary loops appeared less robust and were less common in dermal papilla among samples from both the primary and revision groups, and mast cells were more degranulated. No differences were found in subjective, self-reported postoperative facial sensation. Previous skin elevation was associated with decreased epidermal nerve fiber density and qualitative changes in dermal nerves, capillaries, and mast cells in a clinical sample of patients undergoing rhytidectomy. Future research is needed to determine whether histological findings predict wound healing and to better understand the effects of surgery on regenerative capacity of epidermal nerve fibers. NA.

Late presentation of a deep sternal wound infection and left breast abscess.

PubMed

Mustafa, A; Carr, C; Alkhafagi, S; Mughal, N; Omer, M; Alkhulaifi, A

2014-02-01

In this paper, we present a case review of a 58-year-old female who presented to our emergency department with pyrexia, dyspnoea, dehydration and pain in her left breast six months following coronary artery bypass grafting (CABG). Although her sternotomy wound had healed well, examination revealed fluctuance of the whole precordium and left breast. She underwent antibiotic treatment and subsequent surgical debridement, followed by the application of vacuum-assisted dressings. Surgical reconstruction was deemed unsuitable and therefore the patient continued to be managed with vacuum dressings followed by routine dressings to allow the wound to heal by secondary intention. The patient was discharged three months after initial presentation in a good condition. The wound had completely healed four months later.

Heatshield material selection for advanced ballistic reentry vehicles. [rayon fiber cloth impregnated with phenolic resin

NASA Technical Reports Server (NTRS)

Legendre, P. J.; Holtz, T.; Sikra, J. C.

1980-01-01

The Performance of staple rayon fiber and AVTEX continuous rayon fiber was evaluated as precursor materials for heatshields. The materials studied were referenced to the IRC FM5055A heatshield materials flown during the past decade. Three different arc jet facilities were used to simulate portions of the reentry environment. The IRC FM5055A and the AVTEX FM5055G, both continuous rayon fiber woven materials having the phenolic impregnant filled with carbon particles were compared. The AVTEX continuous fiber, unfilled material FM5822A was also examined to a limited extent. Test results show that the AVTEX FM5055G material provided a close substitute for the IRC FM5055A material both in terms of thermal protection and roll torque performance.

Patterns of wounding in hamadryas baboons (Papio hamadryas) in North American zoos.

PubMed

Wiley, Jodi N; Leeds, Austin; Carpenter, Kamisha D; Kendall, Corinne J

2018-03-01

In North American zoos, hamadryas baboons (Papio hamadryas) have traditionally been housed as single one-male units (single male groups). In recent years, efforts have been made to house hamadryas in groups composed of multiple one-male units (multi-male groups) to more closely mirror their natural social structure, in addition to all-male or bachelor groups to manage surplus males. Given that the majority of social conflict in hamadryas occurs between males during the acquisition and defense of females, it was thought that managing hamadryas in these multi-male groups would result in increased rates of wounding. To assess this, incidences of wounding were recorded over one year across seven zoos (10 social groups, 59 individuals). Overall, we found no difference in wounding rates between group types, or by sex, and group type. These data provide evidence that managing hamadryas in multi-male and bachelor groups is an effective husbandry practice that does not negatively impact the welfare of the individuals, in addition to providing a more species-appropriate social setting for hamadryas in zoos. As the management of hamadryas in multi-male and bachelor groups continues and expands, additional research will be needed to understand what factors contribute to optimal cohesion, and welfare of groups and if wounding rates change as group size continues to increase. © 2018 Wiley Periodicals, Inc.

Evaluation of six holmium:YAG optical fibers for ureteroscopy: What's new in 2009?

NASA Astrophysics Data System (ADS)

Knudsen, Bodo E.; Teichman, Joel M. H.

2010-02-01

The holmium:yttrium aluminum garnet (YAG) laser is the gold standard laser for intracorporeal lithotripsy.1 Optical fibers are utilized to transmit laser energy to the surface of a stone for fragmentation via a predominant photothermal mechanism.2 Previous work has demonstrated that performance characteristics of holmium:YAG optical fibers used for laser lithotripsy varies. Performance may difference not only between fibers made by different manufacturers but also between individual fibers produced by the same manufacturer.3,4 Fiber failure with bending, such as during lower pole ureterorenoscopy, can lead to catastrophic endoscope damage resulting in costly repair. Manufacturers continue to develop new holmium:YAG optical fibers. In this study we evaluate a series of newly commercially available fibers using a previously designed testing protocol. This study was designed to determine the performance and threshold for failure of six newly available holmium:YAG laser fibers from Cook Medical and Fibertech Gmbh. We hypothesize that fiber performance will continue to vary amongst different holmium:YAG optical fibers.

Extended negative pressure wound therapy-assisted dermatotraction for the closure of large open fasciotomy wounds in necrotizing fasciitis patients

PubMed Central

2014-01-01

Background Necrotizing fasciitis (NF) is a rapid progressive infection of the subcutaneous tissue or fascia and may result in large open wounds. The surgical options to cover these wounds are often limited by the patient condition and result in suboptimal functional and cosmetic wound coverage. Dermatotraction can restore the function and appearance of the fasciotomy wound and is less invasive in patients with comorbidities. However, dermatotraction for scarred, stiff NF fasciotomy wounds is often ineffective, resulting in skin necrosis. The authors use extended negative pressure wound therapy (NPWT) as an assist in dermatotraction to close open NF fasciotomy wounds. The authors present the clinical results, followed by a discussion of the clinical basis of extended NPWT-assisted dermatotraction. Methods A retrospective case series of eight patients with NF who underwent open fasciotomy was approved for the study. After serial wound preparation, dermatotraction was applied in a shoelace manner using elastic vessel loops. Next, the extended NPWT was applied over the wound. The sponge was three times wider than the wound width, and the transparent covering drape almost encircled the anatomical wound area. The negative pressure of the NPWT was set at a continuous 100 mmHg by suction barometer. The clinical outcome was assessed based on wound area reduction after treatment and by the achievement of direct wound closure. Results After the first set of extended NPWT-assisted dermatotraction procedures, the mean wound area was significantly decreased (658.12 cm2 to 29.37 cm2; p = 0.002), as five out of eight patients achieved direct wound closure. One patient with a chest wall defect underwent latissimus dorsi musculocutaneous flap coverage, with primary closure of the donor site. Two Fournier’s gangrene patients underwent multiple sets of treatment and finally achieved secondary wound closure with skin grafts. The patients were followed up for 18.3 months on average and showed satisfactory results without wound recurrence. Conclusions Extended NPWT-assisted dermatotraction advances scarred, stiff fasciotomy wound margins synergistically in NF and allows direct closure of the wound without complications. This method can be another good treatment option for the NF patient with large open wounds whose general condition is unsuitable for extensive reconstructive surgery. PMID:24731449

An efficient method for supercontinuum generation in dispersion-tailored Lead-silicate fiber taper

NASA Astrophysics Data System (ADS)

Chen, Z.; Ma, S.; Dutta, N. K.

2010-08-01

In this paper we theoretically study the broadband mid-IR supercontinuum generation (SCG) in a lead-silicate microstructured fiber (the glass for simulation is SF57). The total dispersion of the fiber can be tailored by changing the core diameter of the fiber so that dispersion profiles with two zero dispersion wavelengths (ZDWs) can be obtained. Numerical simulations of the SCG process in a 4 cm long SF57 fiber/fiber taper seeded by femto-second pulses at telecommunications wavelength of 1.55 µm are presented. The results show that a fiber taper features a continuous shift of the longer zero dispersion wavelength. This extends the generated continuum to a longer wavelength region compared to fibers with fixed ZDWs. The phase-matching condition (PMC) is continuously modified in the fiber taper and the bandwidth of the generated dispersive waves (DWs) is significantly broadened.

40 CFR 414.30 - Applicability; description of the other fibers subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS... classified under SIC 2823 cellulosic man-made fibers, except Rayon, and SIC 2824 synthetic organic fibers...

Long-term Effects of Combat Ready Clamp Application to Control Junctional Hemorrhage in Swine

DTIC Science & Technology

2014-01-01

wounds were equally affected in the CRoC-treated and control groups and showed only normal regenerative changes. Muscle (peroneus tertius) fiber ...full function in 3 days ( p 0.001). At 2 weeks, muscle strength of CRoC-applied legs was diminished ( p G 0.05 vs. baselines or controls). Injury...necrosis of lumbar muscles with significant disabilities. CONCLUSION: Two-hour inguinal application of CRoC caused mild and reversible ischemic injuries

Rimmed and edge thickened Stodola shaped flywheel

DOEpatents

Kulkarni, S.V.; Stone, R.G.

1983-10-11

A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body composed of essentially planar isotropic high strength material. The flywheel body is enclosed by a rim of circumferentially wound fiber embedded in resin. The rim promotes flywheel safety and survivability. The flywheel has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability. 6 figs.

Rimmed and edge thickened stodola shaped flywheel. [Patent application

DOEpatents

Kulkarni, S.V.; Stone, R.G.

1980-09-24

A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body composed of essentially planar isotropic high strength material. The flywheel body is enclosed by a rim of circumferentially wound fiber embedded in resin. The rim promotes flywheel safety and survivability. The flywheel has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability.

Composite laminated shells under internal pressure

NASA Technical Reports Server (NTRS)

Yuan, F. G.

1992-01-01

A theoretical study is conducted of the response of filament-wound composite shells under internal pressure; a system of sixth-order ordinary differential equations is obtained by means of the cylindrically anisotropic elasticity field equations and Lekhnitskii's (1963) stress functions. The general expressions for the stresses and displacements in the laminated composite shells under internal pressure are discussed. Attention is given to the influence of the degree of material anisotropy and fiber orientation on the axial and induced twisting deformation.

INCOMPLETE REPAIR OF RETINAL STRUCTURE AFTER VITRECTOMY WITH INTERNAL LIMITING MEMBRANE PEELING.

PubMed

Hisatomi, Toshio; Tachibana, Takashi; Notomi, Shoji; Nakatake, Shunji; Fujiwara, Kohta; Murakami, Yusuke; Ikeda, Yasuhiro; Yoshida, Shigeo; Enaida, Hiroshi; Murata, Toshinori; Sakamoto, Taiji; Sonoda, Koh-Hei; Ishibashi, Tatsuro

2017-08-01

To examine retinal changes after vitrectomy with internal limiting membrane (ILM) peeling, we used a cynomolgus monkey model and focused on surgical damages of ILM peeling for long observational period of 3 years. Vitrectomy was performed followed by ILM peeling similar to clinical settings in humans. Ultrastructural changes of the retina were investigated by light, transmission, and scanning electron microscopy at 3 months and 3 years after ILM peeling. Ultrastructural study showed that the ILM peeled area was still clearly recognized after 3 years. The Müller cell processes covered most of the retina; however, the nerve fiber layer was partly uncovered and exposed to the vitreous space. The arcuate linear nerve fiber bundles were observed as comparable with dissociated optic nerve fiber layer appearance. Small round retinal surface defects were also observed around macula, resembling the dimple sign. Forceps-related retinal thinning was also found on the edge of ILM peeling, where we started peeling with fine forceps. The ultrastructural studies showed that most of ILM peeling area was covered with glial cells during wound healing processes. Retinal changes were found comparable with dissociated optic nerve fiber layer appearance or dimple sign, which were clinically observed with optical coherence tomography.

Continuous unidirectional fiber reinforced composites: Fabrication and testing

NASA Technical Reports Server (NTRS)

Weber, M. D.; Spiegel, F. X.; West, Harvey A.

1994-01-01

The study of the anisotropic mechanical properties of an inexpensively fabricated composite with continuous unidirectional fibers and a clear matrix was investigated. A method has been developed to fabricate these composites with aluminum fibers and a polymer matrix. These composites clearly demonstrate the properties of unidirectional composites and cost less than five dollars each to fabricate.

Evaluation of the antibacterial activity of the Althaea officinalis L. leaf extract and its wound healing potency in the rat model of excision wound creation.

PubMed

Rezaei, Maryam; Dadgar, Zeynab; Noori-Zadeh, Ali; Mesbah-Namin, Seyed Alireza; Pakzad, Iraj; Davodian, Elham

2015-01-01

Wound is defined simply as the disruption of the biochemical, cellular, and anatomic continuity of a tissue. Plants and their extracts known as phytomedicine have immense potential for the management and treatment of wounds. Due to the undesirable side effects, in the control and treatment of the wound infections, it is recommended to use natural materials such as phytochemicals instead of chemically synthesized drugs. Thus, the aim of this research was to study the anti-microbial and wound healing potential of Althaea officinalis L. hydroalchoholic extract in comparison with ciprofloxacin, gentamicin, and penicillin antibiotics on clinical strains as well as pathogenic bacteria such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes under in vitro conditions using micro broth dilution and disc diffusion methods. Moreover, MIC and MBC of its hydroalchoholic extract was also evaluated. The results showed that although Althaea officinalis L. extract was not effective on gram-negative bacteria but it was efficacious on gram-positive bacteria. The extract was also tested in the form of topical administration on excision wound model in rats. In the extract-treated wounds, the wound healing percent was significantly increased in comparison with controls. Based on this research, herbal extract of officinalis L. can be a great candidate for the treatment of gram-positive infections and merits further studies.

Differential effects of Losartan and Atorvastatin in partial and full thickness burn wounds

PubMed Central

Akershoek, Johanneke J.; Brouwer, Katrien M.; Vlig, Marcel; Boekema, Bouke K. H. L.; Beelen, Rob H. J.; Middelkoop, Esther

2017-01-01

Healing of burn wounds is often associated with scar formation due to excessive inflammation and delayed wound closure. To date, no effective treatment is available to prevent the fibrotic process. The Renin Angiotensin System (RAS) was shown to be involved in fibrosis in various organs. Statins (e.g. Atorvastatin), Angiotensin receptor antagonists (e.g. Losartan) and the combination of these drugs are able to reduce the local RAS activation, and reduced fibrosis in other organs. We investigated whether inhibition of the RAS could improve healing of burn wounds by treatment with Atorvastatin, Losartan or the combination of both drugs. Therefore, full and partial thickness burn wounds were inflicted on both flanks of Yorkshire pigs. Oral administration of Atorvastatin, Losartan or the combination was started at post-burn day 1 and continued for 28 days. Full thickness wounds were excised and transplanted with an autologous meshed split-thickness skin graft at post-burn day 14. Partial thickness wounds received conservative treatment. Atorvastatin treatment resulted in enhanced graft take and wound closure of the full thickness wounds, faster resolution of neutrophils compared to all treatments and reduced alpha-smooth muscle actin positive cells compared to control treatment. Treatment with Losartan and to a lesser extent the combination therapy resulted in diminished graft take, increased wound contraction and poorer scar outcome. In contrast, Losartan treatment in partial thickness wounds decreased the alpha-smooth muscle actin+ fibroblasts and contraction. In conclusion, we showed differential effects of Losartan and Atorvastatin in full and partial thickness wounds. The extensive graft loss seen in Losartan treated wounds is most likely responsible for the poor clinical outcome of these full thickness burn wounds. Therefore, Losartan treatment should not be started before transplantation in order to prevent graft loss. Atorvastatin seems to accelerate the healing process in full thickness wounds possibly by dampening the pro-inflammatory response. PMID:28614412

Differential effects of Losartan and Atorvastatin in partial and full thickness burn wounds.

PubMed

Akershoek, Johanneke J; Brouwer, Katrien M; Vlig, Marcel; Boekema, Bouke K H L; Beelen, Rob H J; Middelkoop, Esther; Ulrich, Magda M W

2017-01-01

Healing of burn wounds is often associated with scar formation due to excessive inflammation and delayed wound closure. To date, no effective treatment is available to prevent the fibrotic process. The Renin Angiotensin System (RAS) was shown to be involved in fibrosis in various organs. Statins (e.g. Atorvastatin), Angiotensin receptor antagonists (e.g. Losartan) and the combination of these drugs are able to reduce the local RAS activation, and reduced fibrosis in other organs. We investigated whether inhibition of the RAS could improve healing of burn wounds by treatment with Atorvastatin, Losartan or the combination of both drugs. Therefore, full and partial thickness burn wounds were inflicted on both flanks of Yorkshire pigs. Oral administration of Atorvastatin, Losartan or the combination was started at post-burn day 1 and continued for 28 days. Full thickness wounds were excised and transplanted with an autologous meshed split-thickness skin graft at post-burn day 14. Partial thickness wounds received conservative treatment. Atorvastatin treatment resulted in enhanced graft take and wound closure of the full thickness wounds, faster resolution of neutrophils compared to all treatments and reduced alpha-smooth muscle actin positive cells compared to control treatment. Treatment with Losartan and to a lesser extent the combination therapy resulted in diminished graft take, increased wound contraction and poorer scar outcome. In contrast, Losartan treatment in partial thickness wounds decreased the alpha-smooth muscle actin+ fibroblasts and contraction. In conclusion, we showed differential effects of Losartan and Atorvastatin in full and partial thickness wounds. The extensive graft loss seen in Losartan treated wounds is most likely responsible for the poor clinical outcome of these full thickness burn wounds. Therefore, Losartan treatment should not be started before transplantation in order to prevent graft loss. Atorvastatin seems to accelerate the healing process in full thickness wounds possibly by dampening the pro-inflammatory response.

Delamination of Composite Cylinders

NASA Astrophysics Data System (ADS)

Davies, Peter; Carlsson, Leif A.

The delamination resistance of filament wound glass/epoxy cylinders has been characterized for a range of winding angles and fracture mode ratios using beam fracture specimens. The results reveal that the delamination fracture resistance increases with increasing winding angle and mode II (shear) fraction (GΠ/G). It was also found that interlaced fiber bundles in the filament wound cylinder wall acted as effective crack arresters in mode I loading. To examine the sensitivity of delamina-tion damage on the strength of the cylinders, external pressure tests were performed on filament-wound glass/epoxy composite cylinders with artificial defects and impact damage. The results revealed that the cylinder strength was insensitive to the presence of single delaminations but impact damage caused reductions in failure pressure. The insensitivity of the failure pressure to a single delamination is attributed to the absence of buckling of the delaminated sublaminates before the cylinder wall collapsed. The impacted cylinders contained multiple delaminations, which caused local reduction in the compressive load capability and reduction in failure pressure. The response of glass/epoxy cylinders was compared to impacted carbon reinforced cylinders. Carbon/epoxy is more sensitive to damage but retains higher implosion resistance while carbon/PEEK shows the opposite trend.

Impedance spectroscopy applied to the fast wounding dynamics of an electrical wound-healing assay in mammalian cells

NASA Astrophysics Data System (ADS)

Bellotti, Mariela I.; Giana, Fabián E.; Bonetto, Fabián J.

2015-08-01

Electrical wound-healing assays are often used as a means to study in vitro cell migration and proliferation. In such analysis, a cell monolayer that sits on a small electrode is electrically wounded and its spectral impedance is then continuously measured in order to monitor the healing process. The relatively slow dynamics of the cell healing have been extensively studied, while those of the much faster wounding phase have not yet been investigated. An analysis of the electrical properties of a particular cell type during this phase could give extra information about the changes in the cell membrane due to the application of the wounding current, and could also be useful to optimize the wounding regime for different cell types. The main issue when trying to register information about these dynamics is that the traditional measurement scheme employed in typical wound-healing assays doesn’t allow the simultaneous application of the wounding signal and measurement of the system’s impedance. In this paper, we overcome this limitation by implementing a measurement strategy consisting of cycles of fast alternating low- and high-voltage signals applied on electrodes covered with mammalian cells. This approach is capable of registering the fast impedance changes during the transient regime corresponding to the cell wounding process. Furthermore, these quasi-simultaneous high- and low-voltage measurements can be compared in order to obtain an empirical correlation between both quantities.

Epidermal grafting versus split-thickness skin grafting for wound healing (EPIGRAAFT): study protocol for a randomised controlled trial.

PubMed

Kanapathy, Muholan; Hachach-Haram, Nadine; Bystrzonowski, Nicola; Harding, Keith; Mosahebi, Afshin; Richards, Toby

2016-05-17

Split-thickness skin grafting (SSG) is an important modality for wound closure. However, the donor site becomes a second, often painful wound, which may take more time to heal than the graft site itself and holds the risk of infection and scarring. Epidermal grafting (EG) is an alternative method of autologous skin grafting that harvests only the epidermal layer of the skin by applying continuous negative pressure on the normal skin to raise blisters. This procedure has minimal donor site morbidity and is relatively pain-free, allowing autologous skin grafting in an outpatient setting. We plan to compare EG to SSG and to further investigate the cellular mechanism by which each technique achieves wound healing. EPIGRAAFT is a multicentre, randomised, controlled trial that compares the efficacy and wound-healing mechanism of EG with SSG for wound healing. The primary outcome measures are the proportion of wounds healed in 6 weeks and the donor site healing time. The secondary outcome measures include the mean time for complete wound healing, pain score, patient satisfaction, health care utilisation, cost analysis, and incidence of adverse events. This study is expected to define the efficacy of EG and promote further understanding of the mechanism of wound healing by EG compared to SSG. The results of this study can be used to inform the current best practise for wound care. Clinicaltrials.gov identifier, NCT02535481 . Registered on 11 August 2015.

Wound-Related Allergic/Irritant Contact Dermatitis.

PubMed

Alavi, Afsaneh; Sibbald, R Gary; Ladizinski, Barry; Saraiya, Ami; Lee, Kachiu C; Skotnicki-Grant, Sandy; Maibach, Howard

2016-06-01

To provide information from a literature review about the prevention, recognition, and treatment for contact dermatitis. This continuing education activity is intended for physicians and nurses with an interest in skin and wound care. After participating in this educational activity, the participant should be better able to:1. Identify signs and symptoms of and diagnostic measures for contact dermatitis.2. Identify causes and risks for contact dermatitis.3. Select appropriate treatment for contact dermatitis and its prevention. Contact dermatitis to wound care products is a common, often neglected problem. A review was conducted to identify articles relevant to contact dermatitis.A PubMed English-language literature review was conducted for appropriate articles published between January 2000 and December 2015.Contact dermatitis is both irritant (80% of cases) or allergic (20% of cases). Frequent use of potential contact allergens and impaired barrier function of the skin can lead to rising sensitization in patients with chronic wounds. Common known allergens to avoid in wound care patients include fragrances, colophony, lanolin, and topical antibiotics.Clinicians should be cognizant of the allergens in wound care products and the potential for sensitization. All medical devices, including wound dressings, adhesives, and bandages, should be labeled with their complete ingredients, and manufacturers should be encouraged to remove common allergens from wound care products, including topical creams, ointments, and dressings.

The Topical Evolution: Free Ions, Orthomolecular Agents, Phytochemicals, and Insect-Produced Substances

PubMed Central

Conner-Kerr, Teresa

2014-01-01

Significance: A variety of topical antiseptic substances have been used historically to treat open wounds with suspected tissue infection or that are slow to heal. However, the effectiveness of these substances in treating infected or recalcitrant wounds remains controversial. Recent Advances: Newly formulated topical antiseptics delivered through differing dressing technologies, such as ionic substances, hold the potential to limit the development of and treat antibiotic-resistant microbes in open wounds. Other topically delivered substances, such as insect-derived substances, orthomolecular agents, and phytochemicals, also present opportunities to optimize wound healing by decreasing tissue bioburden and facilitating the wound healing process. Critical Issues: Limited systemic perfusion of open wounds in individuals with certain diagnoses, such as peripheral arterial disease or necrotizing infection and the increasing number of antibiotic-resistant wound pathogens, suggests a continued role for topically applied antiseptic agents. Likewise, the failure of wounds to heal when treated with standard of care therapy opens the door to innovative treatment approaches that include the natural substances described in this article. Future Directions: Evidence for the use of select topical antiseptic agents from each of the aforementioned categories will be discussed in this article. Additional well-controlled clinical studies are needed to provide definitive recommendations for many of these topical agents. PMID:25126473

The effects of chronic ketorolac tromethamine (toradol) on wound healing.

PubMed

Haws, M J; Kucan, J O; Roth, A C; Suchy, H; Brown, R E

1996-08-01

Intramuscular ketorolac is a commonly used nonsteroidal anti-inflammatory (NSAI) agent for analgesia in surgical patients. Increasing numbers of surgical patients are chronically taking some form of an NSAI drug. We examined the effects of "chronic" intramuscular ketorolac on the healing of a closed linear surgical wound in the rat. Wistar rats were pretreated with 4 mg per kilogram per day ketorolac intramuscularly prior to receiving dorsal incisional wounds. The ketorolac treatment was continued and after 2 weeks the wounds were excised and separated with a tensiometer to measure mechanical properties. Breaking strength was directly measured, tensile strength was calculated, and collagen concentrations at the wound site were determined. A significant decrease in the mean breaking strength was seen in the ketorolac-treated animals when compared to controls. The ketorolac-treated animals had a mean tensile strength less than the controls, although this difference did not reach statistical significance. The mean collagen concentration of the ketorolac-treated wounds was significantly less than the untreated wounds. Use of ketorolac for just 1 week prior to surgery in rats produced a significant decrease in the breaking strength of their wounds. With the increasing use of ketorolac in surgical patients as well as the increasing use of oral NSAI drugs, more study of this effect is warranted.

Wound research funding from alternative sources of federal funds in 2012.

PubMed

Baquerizo Nole, Katherine L; Yim, Elizabeth; Van Driessche, Freya; Davidson, Jeffrey M; Martins-Green, Manuela; Sen, Chandan K; Tomic-Canic, Marjana; Kirsner, Robert S

2014-01-01

Chronic wounds represent a major healthcare burden, costing $25 billion annually, and are associated with high mortality. We previously reported that cutaneous wound healing represented only 0.1% ($29.8 million) of the National Institutes of Health budget. This current study focuses on quantifying the contribution by federal agencies other than the National Institutes of Health for fiscal year 2012. Federal databases including USA Spending, Veterans Affairs, Tracking Accountability in Government Grants Systems, Health Services Research Projects in Progress, and Patient-Centered Outcomes Research Institute, were searched for individual projects addressing wound healing. Twenty-seven projects were identified, totaling funding of $16,588,623 (median: $349,856). Four sponsor institutions accounted for 74% of awarded funds: Department of the Army, National Science Foundation, Department of Veterans Affairs, and Agency for Healthcare Research & Quality. Research projects and cooperative agreements comprised 44% and 37% of awarded grants. New applications and continuing projects represented 52% and 37%. Wound healing represented 0.15% of total medical research funded by the non-National Institutes of Health federal sector. Compared with potential impact on US public health, federal investment in wound research is exiguous. This analysis will draw attention to a disproportionately low investment in wound research and its perils to American public health. © 2014 by the Wound Healing Society.

Frequent Application of the New Gelatin-Collagen Nonwoven Accelerates Wound Healing.

PubMed

Schiefer, Jennifer L; Rath, Rebekka; Held, Manuel; Petersen, Wiebke; Werner, Jan-Ole; Schaller, Hans-Eberhard; Rahmanian-Schwarz, Afshin

2016-02-01

Mortality after chronic wounds is high. Thus, proper and effective therapy is of critical importance. Adult mammalian skin cannot regenerate spontaneously. It heals under scar formation in a process of repair. In general, wound closure is achieved through a combination of contraction, scar formation, and regeneration. To enhance wound healing, research groups are continuously inventing and evaluating novel skin replacement products. A single application of a new gelatin-collagen nonwoven accelerates wound closure of full-thickness skin defects. Therefore, the authors' objective was to evaluate the effect of a higher application frequency of the nonwoven on wound closure in a minipig model. Four full-thickness skin defects were created surgically on the dorsum of 12 Göttingen minipigs. Next, 3 wounds were treated randomly with a novel gelatin-collagen nonwoven in different thicknesses, while the fourth wound was left untreated and served as the control wound. Moreover, 6 minipigs achieved multiple applications of the wound dressing. During the experimental period of 21 days, a close-up photographic documentation was performed. Finally, the areas of the initial wounds were excised and examined histologically. More frequent application of the nonwoven achieved accelerated wound healing and better epidermis quality compared with a single application. Mean time until wound closure of all wounds treated with a multiple application of the nonwoven was 11.0 (± 1.2) days, compared with a single application of the nonwoven with 12.4 (± 1.26) days and control wounds with 13.5 (± 1.19) days. Furthermore, the epidermal thickness of all wounds treated with multiple applications of the nonwoven was increased by 10.67 μm (31.89 ± 8.86 μm, P = .0007) compared with a single application of the nonwoven and by 6.53 μm (27.75 ± 7.24 μm, P = .0435) compared with the control group. Multiple applications of the gelatin-collagen nonwoven may be an appropriate treatment for chronic wounds leading to a fast wound closure through a combination of contraction and re-epithelialization.

Mechanical recycling of continuous fiber-reinforced thermoplastic sheets

NASA Astrophysics Data System (ADS)

Moritzer, Elmar; Heiderich, Gilmar

2016-03-01

This contribution examines possible material recycling of offcuts generated during the production of continuous-fiber-reinforced composite sheets. These sheets consist of a polyamide 6 matrix and glass fiber fabric. In the initial step, the offcut is shredded to obtain particles; following that, the particles are processed in a twin-screw process to produce fiber-reinforced plastic pellets with varying fiber contents. These pellets are intended for use in injection molding processes as a substitution for new raw materials. This investigation centers on the mechanical properties which can be achieved with the recycled material after both the twin-screw process and injection molding.

End-pumped 300 W continuous-wave ytterbium-doped all-fiber laser with master oscillator multi-stage power amplifiers configuration.

PubMed

Yin, Shupeng; Yan, Ping; Gong, Mali

2008-10-27

An end-pumped ytterbium-doped all-fiber laser with 300 W output in continuous regime was reported, which was based on master oscillator multi-stage power amplifiers configuration. Monolithic fiber laser system consisted of an oscillator stage and two amplifier stages. Total optical-optical efficiency of monolithic fiber laser was approximately 65%, corresponding to 462 W of pump power coupled into laser system. We proposed a new method to connect power amplifier stage, which was crucial for the application of end-pumped combiner in high power MOPAs all-fiber laser.

Improved Clinical Efficacy with Wound Support Network Between Hospital and Home Care Service.

PubMed

Bergersen, Tone Kristin; Storheim, Elisabeth; Gundersen, Stina; Kleven, Linn; Johnson, Maria; Sandvik, Leiv; Kvaerner, Kari Jorunn; Ørjasæter, Nils-Otto

2016-11-01

The aim of this study was to test the efficacy of a wound support network model between the primary home care service and the hospital. The impact on wound healing rate, cost benefit, and transfer of knowledge was investigated. The intervention group was exposed to a wound support network (n = 32), and the control group continued standard organization of treatment (n = 21). Nonrandomized controlled study; observations were made before (baseline) and after the implementation of the intervention (12 weeks). Patients with chronic wounds (lasting >6 weeks and with wound area >1 cm) in Oslo, Norway. Closure of the observation wound; wound size; total number of wounds; presence of eczema, edema, and pain; number of dressings per week; time spent per dressing; and number of control appointments at the hospital. The economic impact is calculated for the hospital and for the community of Oslo, Norway. The number of control appointments (t = 3.80, P < .001) was significantly decreased, and the number of completed treatments (P = .02) was significantly increased after 12 weeks in the intervention group compared with the control group. A significant improvement was evident in the intervention group in terms of eczema (P = .02), edema (P = .03), and closing of the observational wound (46.7% cases in the intervention group versus 25.0% in the control group). A wound support network between the primary home care service and the hospital is cost-effective, improves clinical efficacy of the home care services' work, and reduces the need for consultations at the hospital.

Stimulation of Skin and Wound Fibroblast Migration by Mesenchymal Stem Cells Derived from Normal Donors and Chronic Wound Patients

PubMed Central

Rodriguez-Menocal, Luis; Salgado, Marcela; Ford, Dwayne

2012-01-01

Chronic wounds continue to be a major cause of morbidity for patients and an economic burden on the health care system. Novel therapeutic approaches to improved wound healing will need, however, to address cellular changes induced by a number of systemic comorbidities seen in chronic wound patients, such as diabetes, chronic renal failure, and arterial or venous insufficiency. These effects likely include impaired inflammatory cell migration, reduced growth factor production, and poor tissue remodeling. The multifunctional properties of bone marrow-derived mesenchymal stem cells (MSCs), including their ability to differentiate into various cell types and capacity to secrete factors important in accelerating healing of cutaneous wounds, have made MSCs a promising agent for tissue repair and regeneration. In this study we have used an in vitro scratch assay procedure incorporating labeled MSCs and fibroblasts derived from normal donors and chronic wound patients in order to characterize the induction of mobilization when these cells are mixed. A modified Boyden chamber assay was also used to examine the effect of soluble factors on fibroblast migration. These studies suggest that MSCs play a role in skin wound closure by affecting dermal fibroblast migration in a dose-dependent manner. Deficiencies were noted, however, in chronic wound patient fibroblasts and MSCs as compared with those derived from normal donors. These findings provide a foundation to develop therapies targeted specifically to the use of bone marrow-derived MSCs in wound healing and may provide insight into why some wounds do not heal. PMID:23197781

Stimulation of skin and wound fibroblast migration by mesenchymal stem cells derived from normal donors and chronic wound patients.

PubMed

Rodriguez-Menocal, Luis; Salgado, Marcela; Ford, Dwayne; Van Badiavas, Evangelos

2012-03-01

Chronic wounds continue to be a major cause of morbidity for patients and an economic burden on the health care system. Novel therapeutic approaches to improved wound healing will need, however, to address cellular changes induced by a number of systemic comorbidities seen in chronic wound patients, such as diabetes, chronic renal failure, and arterial or venous insufficiency. These effects likely include impaired inflammatory cell migration, reduced growth factor production, and poor tissue remodeling. The multifunctional properties of bone marrow-derived mesenchymal stem cells (MSCs), including their ability to differentiate into various cell types and capacity to secrete factors important in accelerating healing of cutaneous wounds, have made MSCs a promising agent for tissue repair and regeneration. In this study we have used an in vitro scratch assay procedure incorporating labeled MSCs and fibroblasts derived from normal donors and chronic wound patients in order to characterize the induction of mobilization when these cells are mixed. A modified Boyden chamber assay was also used to examine the effect of soluble factors on fibroblast migration. These studies suggest that MSCs play a role in skin wound closure by affecting dermal fibroblast migration in a dose-dependent manner. Deficiencies were noted, however, in chronic wound patient fibroblasts and MSCs as compared with those derived from normal donors. These findings provide a foundation to develop therapies targeted specifically to the use of bone marrow-derived MSCs in wound healing and may provide insight into why some wounds do not heal.

Synthesis and preparation of biodegradable hybrid dextran hydrogel incorporated with biodegradable curcumin nanomicelles for full thickness wound healing.

PubMed

Alibolandi, Mona; Mohammadi, Marzieh; Taghdisi, Seyed Mohammad; Abnous, Khalil; Ramezani, Mohammad

2017-10-30

There is a clinical need for a novel, more efficient therapy for full thickness wound healing. In the current study, curcumin encapsulated PEG-PLA [poly(lactide)-block-poly(ethylene glycol)] nanomicelles were incorporated into dextran hydrogel for a full thickness dermal wound healing application. To assess the application of the hydrogel as a therapeutic wound dressing, its morphology, swelling pattern, kinetics of degradation, and capacity to control curcumin release were evaluated. It was found that the prepared hybrid hydrogel had acceptable biocompatibility, incorporation capacity of curcumin nanomicelles, and mechanical properties. An in vitro release experiment also demonstrated the sustained release of curcumin from dextran hydrogel, which was first controlled by the diffusion of curcumin from hydrogel and continued through hydrogel matrix erosion at the terminal phase. An in vivo wound healing experiment was carried out using dressing hydrogels on full thickness wounds in BALB/c mice. An histological study demonstrated that the application of curcumin nanomicelles incorporated hydrogel could significantly augment the re-epithelialization of epidermis and collagen deposition in the wound area. Expression of CD31 and vimentin in wound tissue was investigated using immunohistochemistry tests on the eighth day post wounding. The results obtained demonstrated that curcumin nanomicelles incorporated hydrogel could significantly accelerate angiogenesis, fibroblast accumulation, and the process of wound healing. Together, the data indicate that the prepared hybrid curcumin PEG-PLA nanomicelles incorporated dextran hydrogel is a promising candidate for full thickness wound treatment that increases re-epithelialization, collagen deposition, angiogenesis, and tissue granulation. Copyright © 2017 Elsevier B.V. All rights reserved.

Adipose Tissue-Derived Stromal Cells for Wound Healing.

PubMed

Goodarzi, Parisa; Alavi-Moghadam, Sepideh; Sarvari, Masoumeh; Tayanloo Beik, Akram; Falahzadeh, Khadijeh; Aghayan, Hamidreza; Payab, Moloud; Larijani, Bagher; Gilany, Kambiz; Rahim, Fakher; Adibi, Hossein; Arjmand, Babak

2018-06-02

Skin as the outer layer covers the body. Wounds can affect this vital organ negatively and disrupt its functions. Wound healing as a biological process is initiated immediately after an injury. This process consists of three stages: inflammation, proliferation, remodeling. Generally, these three stages occur continuously and timely. However, some factors such as infection, obesity and diabetes mellitus can interfere with these stages and impede the normal healing process which results in chronic wounds. Financial burden on both patients and health care systems, negative biologic effect on the patient's general health status and reduction in quality of life are a number of issues which make chronic wounds as a considerable challenge. During recent years, along with advances in the biomedical sciences, various surgical and non-surgical therapeutic methods have been suggested. All of these suggested treatments have their own advantages and disadvantages. Recently, cell-based therapies and regenerative medicine represent promising approaches to wound healing. Accordingly, several types of mesenchymal stem cells have been used in both preclinical and clinical settings for the treatment of wounds. Adipose-derived stromal cells are a cost-effective source of mesenchymal stem cells in wound management which can be easily harvest from adipose tissues through the less invasive processes with high yield rates. In addition, their ability to secrete multiple cytokines and growth factors, and differentiation into skin cells make them an ideal cell type to use in wound treatment. This is a concise overview on the application of adipose-derived stromal cells in wound healing and their role in the treatment of chronic wounds.

Maximizing power output from continuous-wave single-frequency fiber amplifiers.

PubMed

Ward, Benjamin G

2015-02-15

This Letter reports on a method of maximizing the power output from highly saturated cladding-pumped continuous-wave single-frequency fiber amplifiers simultaneously, taking into account the stimulated Brillouin scattering and transverse modal instability thresholds. This results in a design figure of merit depending on the fundamental mode overlap with the doping profile, the peak Brillouin gain coefficient, and the peak mode coupling gain coefficient. This figure of merit is then numerically analyzed for three candidate fiber designs including standard, segmented acoustically tailored, and micro-segmented acoustically tailored photonic-crystal fibers. It is found that each of the latter two fibers should enable a 50% higher output power than standard photonic crystal fiber.

Short-Term Effects of gamma-Irradiation on 1-Aminocyclopropane-1-Carboxylic Acid Metabolism in Early Climacteric Cherry Tomatoes : Comparison with Wounding.

PubMed

Larrigaudière, C; Latché, A; Pech, J C; Triantaphylidès, C

1990-03-01

gamma-Irradiation of early climacteric (breaker) cherry tomatoes (Lycopersicon pimpinellifollium L.) caused a sharp burst in ethylene production during the first hour. The extent of ethylene production was dose dependent and was maximum at about 3 kilograys. The content of 1-aminocyclopropane-1-carboxylic acid (ACC), followed the same evolution as ethylene production, while malonyl ACC increased steadily with time in irradiated fruits. The burst in ethylene production was accompanied by a sharp stimulation of ACC synthase activity which began 15 minutes after irradiation. The stimulation was completely prevented by cycloheximide, but not by actinomycin d or cordycepin. In contrast with irradiation, mechanical wounding continuously stimulated ethylene production over several hours. gamma-Irradiation and cordycepin applied to wounded tissues both caused the cessation of this continuous increase, but the initial burst was still persisting. These data suggest that gamma-irradiation, like wounding, stimulates the translation of preexisting mRNAs. It also reduces, at least temporarily, the subsequent transcription-dependent stimulation of ethylene production. gamma-Irradiation greatly inhibited the activity of ethylene-forming enzyme at doses higher than 1 kilogray. Such sensitivity is in accordance with a highly integrated membranebound enzyme.

Current concepts on burn wound conversion – a review of recent advances in understanding the secondary progressions of burns

PubMed Central

Salibian, Ara A.; Del Rosario, Angelica Tan; De Almeida Moura Severo, Lucio; Nguyen, Long; Banyard, Derek A.; Toranto, Jason D.; Evans, Gregory R.D.; Widgerow, Alan D.

2016-01-01

Burn wound conversion describes the process by which superficial partial thickness burns convert into deeper burns necessitating surgical intervention. Fully understanding and thus controlling this phenomenon continues to defy burn surgeons. However, potentially guiding burn wound progression so as to obviate the need for surgery while still bringing about healing with limited scarring is the major unmet challenge. Comprehending the pathophysiologic background contributing to deeper progression of these burns is an essential prerequisite to planning any intervention. In this study, a review of articles examining burn wound progression over the last five years was conducted to analyze trends in recent burn progression research, determine changes in understanding of the pathogenesis of burn conversion, and subsequently examine the direction for future research in developing therapies. The majority of recent research focuses on applying therapies from other disease processes to common underlying pathogenic mechanisms in burn conversion. While ischemia, inflammation, and free oxygen radicals continue to demonstrate a critical role in secondary necrosis, novel mechanisms such as autophagy have also been shown to contribute affect significantly burn progression significantly. Further research will have to determine whether multiple mechanisms should be targeted when developing clinical therapies. PMID:26787127

[Repair of swine full-thickness cutaneous deficiency by autogenic BMSCs compounded with collagen membrane].

PubMed

He, Lijuan; Liu, Daqing; Bai, Cixian; Yan, Yingfun; Guan, Lidong; Pei, Xuetao

2009-03-01

To supply references to tissue-engineered skin clinical applications with autogenic BMSCs composited collagen membrane to repair swine full-thickness cutaneous deficiency. Twenty mL bone marrow were obtained respectively from 4 swine, autogenic BMSCs were cultured and passed to the 3rd passage. The fresh bovine tendon treated by means of chemically cross-linked was made 5 cm diameter collagen I (Col I) membrane. The 2 x 10(7)/mL P3 swine autogenic BMSCs labeled DAPI were planted to sterile Col I membrane for 24 hours incubation, then the tissue-engineered skin was constructed. The five full-thickness skin defect of 5 cm diameter was excised to the muscle from forward to backward on the back midline two sides of swine. The tissue-engineered skin were implanted in the experimental group, while Col I membrane was implanted in control group. After 3 and 8 weeks of implantation, the two swine wound surface healing circumstance was observed and further evaluated with histology analysis and TEM. After 3 weeks of implantation, the experimental group were observed with fluorescence microscopy and staining for glycogen. After 3 weeks of implantation, the wound surface of control group were observed nigrescene, scab and putrescence, and after 8 weeks of implantation, also evident putrescence and scar. The wound surface of experiment group was alive after 3 weeks implantation, appearance was leveled off and flexible without evident scar. The wound surface recovered well after 8 weeks of implantation, wound surface healing rate was significantly difference between the two groups (P < 0.01). After 3 weeks of implantation, control group were observed acestoma hyperplasia and no epidermal coverage by histology analysis. The experimental group was showed integrity epidermis and dermis structure. The basal layer was crimson and continuously positive with glycogen staining. After 8 weeks of implantation, the experimental group and control group were emerged normal skin structure. After 3 weeks of implantation in control group, a lot of neutrophilic granulocytes and fibroblasts were noticed, but no epidermal structure was observed under TEM. In the experimental group, a lot of epidermal cells were observed, dermatome connection among epidermal cells and hemidesmosome connection between basilar membrane cells and basal membrane were observed in epidermis. In the dermis experimental group, blood capillary endothelial cells were noticed. Furthermore, considerable collagen fiber deposit was found in the surrounding tissue of fibroblasts. After 3 weeks of implantation, BMSCs labeled with DAPI were located reconstructed epidermal basement membrane and dermis by fluorescence microscopy. Tissue-engineered skin which is composited with autogenic BMSCs as seed cells and collagen membrane were potential prospects in application of repairing swine full-thickness cutaneous deficiency.

Effect of topical application of virgin coconut oil on skin components and antioxidant status during dermal wound healing in young rats.

PubMed

Nevin, K G; Rajamohan, T

2010-01-01

The present study was undertaken to evaluate the effect of a topical application of virgin coconut oil (VCO) on excision wounds in young rats. Three sets of experiments with 3 groups of female Sprague-Dawley rats each consisting of 6 animals were used for studying wound closure time, antioxidant status and biochemical parameters. Group 1 was the control; groups 2 and 3 were treated with 0.5 and 1.0 ml VCO, respectively, 24 h after wound creation for 10 days. After the experimental period, the healing property of VCO was evaluated by monitoring the time taken for complete epithelization as well as levels of various parameters of the wound's granulation tissue. The collagen solubility pattern, glycohydrolase activity, and histopathology of the granulation tissue were also analyzed. The antioxidant status during wound healing was monitored continuously for 14 days. VCO-treated wounds healed much faster, as indicated by a decreased time of complete epithelization and higher levels of various skin components. Pepsin-soluble collagen showed a significant increase in VCO- treated wounds, indicating a higher collagen cross-linking. Glycohydrolase activities were also found to be increased due to a higher turnover of collagen. Antioxidant enzyme activities, and reduced glutathione and malondialdehyde levels were found to be increased on the 10th day after wounding, which were found to have returned to normal levels on day 14 in the treated wounds. The lipid peroxide levels were found to be lower in the treated wounds. A histopathological study showed an increase in fibroblast proliferation and neovascularization in VCO-treated wounds compared to controls. The beneficial effect of VCO can be attributed to the cumulative effect of various biologically active minor components present in it. Copyright 2010 S. Karger AG, Basel.

Application of the Single Use Negative Pressure Wound Therapy Device (PICO) on a Heterogeneous Group of Surgical and Traumatic Wounds

PubMed Central

Payne, Caroline; Edwards, Daren

2014-01-01

Objectives: Traumatic wounds and surgery inherently have their complications. Localized infections, wound dehiscence, and excessive wound leakage can be devastating to the patient with a prolonged recovery, but it is also costly to the hospital with an increased length of stay, extra workload, and dressing changes. The single use PICO (Smith and Nephew Healthcare, Hull, United Kingdom) negative pressure wound therapy (NPWT) dressing has revolutionized our management of various acute, chronic, and high output wounds. It requires fewer dressing changes than conventional practice, is used in the outpatient setting, and is a necessary adjuvant therapy to hasten wound healing. Aims: To observe the efficacy of the PICO vacuum-assisted healing within a cost improvement programme. Settings: Plastic surgery department, Royal London Hospital. Materials and Methods: Twenty-one patients with a diversity of postoperative or posttraumatic wounds were considered suitable for PICO application and treated totally on an outpatient basis once the PICO dressing was applied. All wounds were then subjected to continued PICO dressings until healed. Results: All patients tolerated the PICO well with no dressing failure or failure to comply. The number of dressings per patient ranged from 1 to 7. The cost per patient of treatment ranged from £120 to £1578. Estimated cost of all PICO dressing for 21 patients including plastic surgery dressing clinic appointments = £13,345. Median length of treatment to healing (days) = 16; standard deviation = 9.5. Eight patients would have had an inpatient bed stay with conventional therapy, total 24 bed days saved at Bartshealth @£325 per day. Conclusions: The outpatient application of a disposable NPWT can benefit a wide range of clinical wounds that optimizes patient care, promotes rapid wound healing, and importantly helps manage costs. PMID:24917894

Transcription forms and remodels supercoiling domains unfolding large-scale chromatin structures

PubMed Central

Naughton, Catherine; Avlonitis, Nicolaos; Corless, Samuel; Prendergast, James G.; Mati, Ioulia K.; Eijk, Paul P.; Cockroft, Scott L.; Bradley, Mark; Ylstra, Bauke; Gilbert, Nick

2013-01-01

DNA supercoiling is an inherent consequence of twisting DNA and is critical for regulating gene expression and DNA replication. However, DNA supercoiling at a genomic scale in human cells is uncharacterized. To map supercoiling we used biotinylated-trimethylpsoralen as a DNA structure probe to show the genome is organized into supercoiling domains. Domains are formed and remodeled by RNA polymerase and topoisomerase activities and are flanked by GC-AT boundaries and CTCF binding sites. Under-wound domains are transcriptionally active, enriched in topoisomerase I, “open” chromatin fibers and DNaseI sites, but are depleted of topoisomerase II. Furthermore DNA supercoiling impacts on additional levels of chromatin compaction as under-wound domains are cytologically decondensed, topologically constrained, and decompacted by transcription of short RNAs. We suggest that supercoiling domains create a topological environment that facilitates gene activation providing an evolutionary purpose for clustering genes along chromosomes. PMID:23416946

Impact damage and residual tension strength of a thick graphite/epoxy rocket motor case

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1992-01-01

Impacters of various masses were dropped from various heights onto thick graphite/epoxy filament-wound cylinders. The cylinders represented filament-wound cases made for the booster motors of the Space Shuttle. Tups of various shapes were affixed to the impacters. Some of the cylinders were filled with inert propellant, and some were empty. The cylinders were impacted numerous times around the circumference and then cut into tension coupons, each containing an impact site. The size of the damage and the residual tension strength were measured. For hemispherical tups, strength was reduced as much as 30 percent by nonvisible damage. The damage consisted of matrix cracking and broken fibers. Analytical methods were used to predict the damage and residual tension strength. A factor of safety to account for nonvisible damage was determined. For corner and rod shaped tups, any damage that resulted in strength loss was readily visible.

Durability of filament-wound composite flywheel rotors

NASA Astrophysics Data System (ADS)

Koyanagi, Jun

2012-02-01

This paper predicts the durability of two types of flywheels, one assumes to fail in the radial direction and the other assumes to fail in the circumferential direction. The flywheel failing in the radial direction is a conventional filament-wound composite flywheel and the one failing in the circumferential direction is a tailor-made type. The durability of the former is predicted by Micromechanics of Failure (MMF) (Ha et al. in J. Compos. Mater. 42:1873-1875, 2008), employing time-dependent matrix strength, and that of the latter is predicted by Simultaneous Fiber Failure (SFF) (Koyanagi et al. in J. Compos. Mater. 43:1901-1914, 2009), employing identical time-dependent matrix strength. The predicted durability of the latter is much greater than that of the former, depending on the interface strength. This study suggests that a relatively weak interface is necessary for high-durability composite flywheel fabrication.

Micromechanical analysis of thermo-inelastic multiphase short-fiber composites

NASA Technical Reports Server (NTRS)

Aboudi, Jacob

1994-01-01

A micromechanical formulation is presented for the prediction of the overall thermo-inelastic behavior of multiphase composites which consist of short fibers. The analysis is an extension of the generalized method of cells that was previously derived for inelastic composites with continuous fibers, and the reliability of which was critically examined in several situations. The resulting three dimensional formulation is extremely general, wherein the analysis of thermo-inelastic composites with continuous fibers as well as particulate and porous inelastic materials are merely special cases.

Vibration sensing using a tapered bend-insensitive fiber based Mach-Zehnder interferometer.

PubMed

Xu, Yanping; Lu, Ping; Qin, Zengguang; Harris, Jeremie; Baset, Farhana; Lu, Ping; Bhardwaj, Vedula Ravi; Bao, Xiaoyi

2013-02-11

In this study, a novel fiber-optic sensor consisting of a tapered bend-insensitive fiber based Mach-Zehnder interferometer is presented to realize damped and continuous vibration measurement. The double cladding structure and the central coating region of the in-fiber interferometer ensure an enhanced mechanical strength, reduced external disturbance, and a more uniform spectrum. A damped vibration frequency range of 29-60 Hz as well as continuous vibration disturbances ranging from 1 Hz up to 500 kHz are successfully demonstrated.

Production of continuous mullite fiber via sol-gel processing

NASA Technical Reports Server (NTRS)

Tucker, Dennis S.; Sparks, J. Scott; Esker, David C.

1990-01-01

The development of a continuous ceramic fiber which could be used in rocket engine and rocket boosters applications was investigated at the Marshall Space Flight Center. Methods of ceramic fiber production such as melt spinning, chemical vapor deposition, and precursor polymeric fiber decomposition are discussed and compared with sol-gel processing. The production of ceramics via the sol-gel method consists of two steps, hydrolysis and polycondensation, to form the preceramic, followed by consolidation into the glass or ceramic structure. The advantages of the sol-gel method include better homogeneity and purity, lower preparation temperature, and the ability to form unique compositions. The disadvantages are the high cost of raw materials, large shrinkage during drying and firing which can lead to cracks, and long processing times. Preparation procedures for aluminosilicate sol-gel and for continuous mullite fibers are described.

Microstructure, hardness and modulus of carbon-ion-irradiated new SiC fiber (601-4)

NASA Astrophysics Data System (ADS)

Huang, Qing; Lei, Guanhong; Liu, Renduo; Li, Jianjian; Yan, Long; Li, Cheng; Liu, Weihua; Wang, Mouhua

2018-05-01

Two types of SiC fibers, one is low-oxygen and carbon-rich fiber denoted by 601-4 and the other is low-oxygen and near-stoichiometric Tyranno SA, were irradiated with 450 keV C+ ions at room temperature. The Raman spectra indicate that irradiation induced distortion and amorphization of SiC crystallites in fibers. TEM characterization of Tyranno SA suggests that SiC crystallites undergo a continued fragmentation into smaller crystalline islands and a continued increase of surrounding amorphous structure. The SiC nano-crystallites (<15 nm) in 601-4 fiber are more likely to be amorphized than larger crystallites (∼200 nm) in Tyranno SA. The hardness and modulus of 601-4 continuously decreases with increasing fluence, while that of Tyranno SA first increases and then decreases.

Temporary skin grafts based on hybrid graphene oxide-natural biopolymer nanofibers as effective wound healing substitutes: pre-clinical and pathological studies in animal models.

PubMed

Mahmoudi, N; Eslahi, N; Mehdipour, A; Mohammadi, M; Akbari, M; Samadikuchaksaraei, A; Simchi, A

2017-05-01

In recent years, temporary skin grafts (TSG) based on natural biopolymers modified with carbon nanostructures have received considerable attention for wound healing. Developments are required to improve physico-mechanical properties of these materials to match to natural skins. Additionally, in-deep pre-clinical examinations are necessary to ensure biological performance and toxicity effect in vivo. In the present work, we show superior acute-wound healing effect of graphene oxide nanosheets embedded in ultrafine biopolymer fibers (60 nm) on adult male rats. Nano-fibrous chitosan-based skin grafts crosslinked by Genepin with physico-mechanical properties close to natural skins were prepared by electrospinning of highly concentrated chitosan- polyvinylpyrrolidone solutions containing graphene oxide (GO) nanosheets. No surfactants and organic solvents were utilized to ensure high biocompatibility of the fibrous structure. In vitro evaluations by human skin fibroblast cells including live and dead assay and MTT results show that GO promote cell viability of porous nanofibrous membrane while providing enhanced bactericidal capacity. In vivo studies on rat's skin determine accelerated healing effect, i.e. a large open wound (1.5 × 1.5 cm 2 ) is fully regenerated after 14-day of post operation while healing is observed for sterile gauze sponge (as the control). Pathological studies support thick dermis formation and complete epithelialization in the presence of 1.5 wt% GO nanosheets. Over 99% wound healing occurs after 21 days for the injury covered with TSG containing 1.5 wt% GO while this would takes weeks for the control. Therefore, the developed materials have a high potential to be used as TSG as pre-clinical testing has shown.

Systemic depletion of macrophages in the subacute phase of wound healing reduces hypertrophic scar formation.

PubMed

Zhu, Zhensen; Ding, Jie; Ma, Zengshuan; Iwashina, Takashi; Tredget, Edward E

2016-07-01

Hypertrophic scars are caused by trauma or burn injuries to the deep dermis and can cause cosmetic disfigurement and psychological issues. Studies suggest that M2-like macrophages are pro-fibrotic and contribute to hypertrophic scar formation. A previous study from our lab showed that M2 macrophages were present in developing hypertrophic scar tissues in vivo at 3-4 weeks after wounding. In this study, the effect of systemic macrophage depletion on scar formation was explored at subacute phase of wound healing. Thirty-six athymic nude mice that received human skin transplants were randomly divided into macrophage depletion group and control group. The former received intraperitoneal injections of clodronate liposomes while the controls received sterile saline injections on day 7, 10, and 13 postgrafting. Wound area, scar thickness, collagen abundance and collagen bundle structure, mast cell infiltration, myofibroblast formation, M1, and M2 macrophages together with gene expression of M1 and M2 related factors in the grafted skin were investigated at 2, 4, and 8 weeks postgrafting. The transplanted human skin from the control group developed contracted, elevated, and thickened scars while the grafted skin from the depletion group healed with significant less contraction and elevation. Significant reductions in myofibroblast number, collagen synthesis, and hypertrophic fiber morphology as well as mast cell infiltration were observed in the depletion group compared to the control group. Macrophage depletion significantly reduced M1 and M2 macrophage number in the depletion group 2 weeks postgrafting as compared to the control group. These findings suggest that systemic macrophage depletion in subacute phase of wound healing reduces scar formation, which provides evidence for the pro-fibrotic role of macrophages in fibrosis of human skin as well as insight into the potential benefits of specifically depleting M2 macrophages in vivo. © 2016 by the Wound Healing Society.

Microfluidic guillotine for single-cell wound repair studies

NASA Astrophysics Data System (ADS)

Blauch, Lucas R.; Gai, Ya; Khor, Jian Wei; Sood, Pranidhi; Marshall, Wallace F.; Tang, Sindy K. Y.

2017-07-01

Wound repair is a key feature distinguishing living from nonliving matter. Single cells are increasingly recognized to be capable of healing wounds. The lack of reproducible, high-throughput wounding methods has hindered single-cell wound repair studies. This work describes a microfluidic guillotine for bisecting single Stentor coeruleus cells in a continuous-flow manner. Stentor is used as a model due to its robust repair capacity and the ability to perform gene knockdown in a high-throughput manner. Local cutting dynamics reveals two regimes under which cells are bisected, one at low viscous stress where cells are cut with small membrane ruptures and high viability and one at high viscous stress where cells are cut with extended membrane ruptures and decreased viability. A cutting throughput up to 64 cells per minute—more than 200 times faster than current methods—is achieved. The method allows the generation of more than 100 cells in a synchronized stage of their repair process. This capacity, combined with high-throughput gene knockdown in Stentor, enables time-course mechanistic studies impossible with current wounding methods.

A fiber-based quasi-continuous-wave quantum key distribution system

PubMed Central

Shen, Yong; Chen, Yan; Zou, Hongxin; Yuan, Jianmin

2014-01-01

We report a fiber-based quasi-continuous-wave (CW) quantum key distribution (QKD) system with continuous variables (CV). This system employs coherent light pulses and time multiplexing to maximally reduce cross talk in the fiber. No-switching detection scheme is adopted to optimize the repetition rate. Information is encoded on the sideband of the pulsed coherent light to fully exploit the continuous wave nature of laser field. With this configuration, high secret key rate can be achieved. For the 50 MHz detected bandwidth in our experiment, when the multidimensional reconciliation protocol is applied, a secret key rate of 187 kb/s can be achieved over 50 km of optical fiber against collective attacks, which have been shown to be asymptotically optimal. Moreover, recently studied loopholes have been fixed in our system. PMID:24691409

[Application of high-frequency ultrasound in dermabrasion of patients with deep partial-thickness burns].

PubMed

Zang, C Y; Cao, Y Q; Xue, W J; Zhao, R; Zhang, M; Zhang, Y H; Feng, Z; Wang, Y B

2017-02-20

Objective: To investigate the application of high-frequency ultrasound in dermabrasion of patients with deep partial-thickness burns. Methods: Twenty-six patients with deep partial-thickness burns conforming to the study criteria were hospitalized in our unit from March 2015 to March 2016. Patients were all performed with dermabrasion. The structure of skin tissue and blood flow signals of uninjured side and wounds before dermabrasion, and those of wounds immediately post dermabrasion and on post dermabrasion day (PDD) 1, 3, 5, 7, 10, 14, and 21 were detected with high-frequency ultrasound, and the percentage of blood flow signals was calculated. According to the results of comparison between percentage of blood flow signals of wounds and that of normal skin before dermabrasion, patients were divided into no significant decrease group (NSD, n =19) and significant decrease group (SD, n =7). Wound healing time of patients in two groups was recorded. Data were processed with analysis of variance of repeated measurement, LSD test, t test and Chi-square test. The correlation between the percentage of blood flow signals of wounds before dermabrasion and wound healing time of 26 patients were analyzed by Spearman correlation analysis. Results: (1) Epidermis of normal skin of patients in two groups before dermabrasion showed continuous smooth linear hyperecho, which was stronger than that of dermis, and boundary of dermis and subcutaneous tissue showed stronger discontinuous linear echo than that of dermis, which gradually transited to subcutaneous tissue. In group NSD, epidermis of wound of patients before dermabrasion showed intermittent rough linear echo, which was weaker than that of normal skin epidermis, and there was no obvious abnormity of boundary between dermis and subcutaneous tissue. Immediately post dermabrasion and on PDD 1, no linear hyperecho of epidermis was observed, showing complete attrition of epidermis, and the echo of dermis and subcutaneous tissue had no obvious change as compared with that before dermabrasion, with flat surface of dermis and partly abraded superficial-dermis but relatively well preserved dermal tissue in whole. The epidermis showed discontinuous linear hyperecho, and epidermis was discontinuously regenerated on PDD 3 and 5. Partial continuous linear hyperecho was detected in the epidermis, showing partial continuous regeneration of epidermis on PDD 7 and 10. The regenerated epidermis was thicker than normal skin epidermis and showed rough linear hyperecho with non-uniform thickness on PDD 14. The regenerated epidermis was thicker than normal skin epidermis and showed rather smooth linear hyperecho with uniform thickness on PDD 21. In group SD, the structure of epidermis and dermis of wound of patients before dermabrasion, immediately post dermabrasion, and on PDD 1 was similar to that in group NSD, but the echo of boundary of dermis and subcutaneous tissue was weakened in different degrees. There was no linear hyperecho of epidermis, showing no epidermis was regenerated on PDD 3 and 5. Intermittent regeneration of epidermis appeared on PDD 7 and 10 with intermittent linear hyperecho. Partial continuous linear hyperecho was detected in the epidermis, showing partial continuous regeneration of epidermis on PDD 14 and 21. (2) The percentages of blood flow signals of wounds of patients in group NSD before dermabrasion, immediately post dermabrasion, and on PDD 1 were (3.1±1.3)%, (6.5±2.0)%, and (5.3±1.9)% respectively, higher than those in group SD [(0.9±1.1)%, (3.5±1.3)%, and (3.6±0.9)% respectively, P <0.05 or P <0.01]. The percentages of blood flow signals of wounds of patients in two groups were similar at the other time points (with P values above 0.05). Compared with the percentage of normal skin in the same group [(3.2±0.7)%], the percentages of blood flow signals of wounds of patients in group NSD were significantly increased immediately post dermabrasion and on PDD 1 (with P values below 0.01) but had no significant change at the other time points (with P values above 0.05). The percentage of blood flow signals of wounds of patients before dermabrasion in group SD was significantly lower than that of normal skin in the same group [(2.8±0.6)%, P <0.01]. The percentage of blood flow signals of wounds of patients in group SD was close to that of normal skin in the same group at each time point post dermabrasion (with P values above 0.05). (3) The wound healing time of patients in group NSD was (16.2±2.5) d, lower than that in group SD [(30.9±2.9) d, t =12.67, P <0.01]. There was obvious negative correlation between the percentage of blood flow signals of wounds before dermabrasion and wound healing time of 26 patients ( r =-0.77, P <0.01). Conclusions: High-frequency ultrasound is a good way to observe the imaging features of wounds in patients with deep partial-thickness burns before and after dermabrasion, and it can provide objective imaging evidence for the performance of dermabrasion in patients with deep partial-thickness burns.

Lysozyme-immobilized electrospun PAMA/PVA and PSSA-MA/PVA ion-exchange nanofiber for wound healing.

PubMed

Tonglairoum, Prasopchai; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Opanasopit, Praneet

2014-08-27

Abstract This research was aimed to develop the lysozyme immobilized ion-exchange nanofiber mats for wound healing. To promote the healing process, the PSSA-MA/PVA and PAMA ion-exchange nanofiber mats were fabricated to mimic the extracellular matrix structure using electrospinning process followed by thermally crosslinked. Lysozyme was immobilized on the ion-exchane nanofibers by an adsorption method. The ion-exchange nanofibers were investigated using SEM, FTIR and XRPD. Moreover, the lysozyme-immobilized ion-exchange nanofibers were further investigated for lysozyme content and activity, lysozyme release and wound healing activity. The fiber diameters of the mats were in the nanometer range. Lysozyme was gradually absorbed into the PSSA-MA/PVA nanofiber with higher extend than that is absorbed on the PAMA/PVA nanofiber and exhibited higher activity than lysozyme-immobilized PAMA/PVA nanofiber. The total contents of lysozyme on the PSSA-MA/PVA and PAMA/PVA nanofiber were 648 and 166 µg/g, respectively. FTIR and lysozyme activity results confirmed the presence of lysozyme on the nanofiber mats. The lysozyme was released from the PSSA-MA/PVA and PAMA/PVA nanofiber in the same manner. The lysozyme-immobilized PSSA-MA/PVA nanofiber mats and lysozyme-immobilized PAMA/PVA nanofiber mats exhibited significantly faster healing rate than gauze and similar to the commercial antibacterial gauze dressing. These results suggest that these nanofiber mats could provide the promising candidate for wound healing application.

Continuous-wave supercontinuum laser based on an erbium-doped fiber ring cavity incorporating a highly nonlinear optical fiber.

PubMed

Lee, Ju Han; Takushima, Yuichi; Kikuchi, Kazuro

2005-10-01

We experimentally demonstrate a novel erbium-doped fiber based continuous-wave (cw) supercontinuum laser. The laser has a simple ring-cavity structure incorporating an erbium-doped fiber and a highly nonlinear dispersion-shifted fiber (HNL-DSF). Differently from previously demonstrated cw supercontinuum sources based on single propagation of a strong Raman pump laser beam through a highly nonlinear fiber, erbium gain inside the cavity generates a seed light oscillation, and the oscillated light subsequently evolves into a supercontinuum by nonlinear effects such as modulation instability and stimulated Raman scattering in the HNL-DSF. High quality of the depolarized supercontinuum laser output with a spectral bandwidth larger than 250 nm is readily achieved.

Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2016-12-01

This factsheet describes a project that developed a new, continuous manufacturing process to make high molecular weight, high thermal conductivity polyethylene fibers and sheets to replace metals and ceramics in heat transfer applications.

Factors affecting perioperative mortality and wound-related complications following major lower extremity amputations.

PubMed

Stone, Patrick A; Flaherty, Sarah K; Aburahma, Ali F; Hass, Stephen M; Jackson, J Michelle; Hayes, J David; Hofeldt, Matthew J; Hager, Casey S; Elmore, Michael S

2006-03-01

Major lower extremity amputations continue to be associated with significant morbidity and mortality, yet few recent large series have evaluated factors associated with perioperative mortality and wound complications. The purpose of this study was to examine factors affecting perioperative mortality and wound-related complications following major lower extremity amputation. A retrospective review was conducted of all adult patients who underwent nontraumatic major lower extremity amputations over a 5-year period at a single tertiary-care center in southern West Virginia. Demographic and clinical data, perioperative data, and outcomes were collected and analyzed to identify any relationship with perioperative mortality, as well as wound complications and early revisions (within 90 days) to a more proximal level. Variables were examined using chi-squared, two-tailed t-tests, and logistic regression. Three hundred eighty patients (61% male) underwent 412 major lower extremity amputations during 1999-2003. The initial level of amputation included 230 below-knee (BKA), 149 above-knee (AKA), and one hip disarticulation. Perioperative mortality was 15.5% (n = 59). From a regression model, age, albumin level, AKA, and lack of a previous coronary artery bypass graft (CABG) were independently related to mortality. Patients who did not have a previous CABG were nearly three times more likely to die than those who did (p = 0.038). Overall early wound complications were noted in 13.4% (n = 51). Four factors were independently related to experiencing a 90-day wound complication: BKA, community (rather than care facility) living, type of anesthesia, and preoperative hematocrit >30%. Major lower extremity amputation in patients with peripheral vascular disease continues to be associated with considerable perioperative morbidity and mortality. Even though the surgical procedure itself may not be challenging from a technical standpoint, underlying medical conditions put this group at high risk for perioperative death. Wound-healing problems are frequently encountered and must be minimized to facilitate early mobilization and hospital discharge.

Rimmed and edge thickened Stodola shaped flywheel

DOEpatents

Kulkarni, Satish V.; Stone, Richard G.

1983-01-01

A flywheel (10) is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel (10) has a body (15) composed of essentially planar isotropic high strength material. The flywheel (10) body (15) is enclosed by a rim (50) of circumferentially wound fiber (2) embedded in resin (3). The rim (50) promotes flywheel (10) safety and survivability. The flywheel (10) has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability.

[Magnetic therapy in treatment of patients with leg ulcers].

PubMed

Alekseenko, A V; Gusak, V V; Tarabanchuk, V V; Iftodiĭ, A G; Sherban, N G; Stoliar, V F

1998-01-01

Various magnetic (continuous current, alternating current and "running" impulse) fields were applied in 74 patients with trophic ulcers of lower limbs. 10-12 days after the beginning of the magnetic therapy wound surface has completely cleaned from necrotic tissues, surrounding inflammatory changes eliminated, epithelization of the wounds began. The most pronounced clinical effect was observed after the use of "running" impulse of magnetic field.

The impact of mechanism on the management and outcome of penetrating colonic trauma.

PubMed

Oosthuizen, G V; Kong, V Y; Estherhuizen, T; Bruce, J L; Laing, G L; Odendaal, J J; Clarke, D L

2018-02-01

Introduction In light of continuing controversy surrounding the management of penetrating colonic injuries, we set out to compare the outcome of penetrating colonic trauma according to whether the mechanism of injury was a stab wound or a gunshot wound. Methods Our trauma registry was interrogated for the 5-year period from January 2012 to December 2016. All patients over the age of 18 years with penetrating trauma (stab or gunshot) and with intraoperatively proven colonic injury were reviewed. Details of the colonic and concurrent abdominal injuries were recorded, together with the operative management strategy. In-hospital morbidities were divided into colon-related and non-colon related morbidities. The length of hospital stay and mortality were recorded. Direct comparison was made between patients with stab wounds and gunshot wounds to the colon. Results During the 5-year study period, 257 patients sustained a colonic injury secondary to penetrating trauma; 95% (244/257) were male and the mean age was 30 years. A total of 113 (44%) sustained a gunshot wound and the remaining 56% (144/257) sustained a stab wound. Some 88% (226/257) of all patients sustained a single colonic injury, while 12% (31/257) sustained more than one colonic injury. A total of 294 colonic injuries were found at laparotomy. Multiple colonic injuries were less commonly encountered in stab wounds (6%, 9/144 vs. 19%, 22/113, P < 0.001). Primary repair was more commonly performed for stab wounds compared with gunshot wounds (118/144 vs. 59/113, P < 0.001). Patients with gunshot wounds were more likely to need admission to intensive care, more likely to experience anastomotic failure, and had higher mortality. Conclusions It would appear that colonic stab wounds and colonic gunshot wounds are different in terms of severity of the injury and in terms of outcome. While primary repair is almost always applicable to the management of colonic stab wounds, the same cannot be said for colonic gunshot wounds. The management of colonic gunshot wounds should be examined separately from that of stab wounds.

A polarisation maintaining fiber optimized for high temperature gyroscopes

NASA Astrophysics Data System (ADS)

Tutu, F.; Hill, Mark; Cooper, Laurence; Gillooly, A.

2015-05-01

Fiber optic gyroscopes (FOGs) are being used within increasingly severe environments, requiring operational temperatures in excess of the standard operating range for FOGs. Applications requiring these higher temperatures include: directional drilling of wells in oil and gas fields, space applications and military FOG applications. This paper will describe the relative merits of two high temperature acrylate coatings for an optical fiber designed for a FOG in such operating environments. Results for two high temperature acrylates are presented, tested in a 200m length of loose wound fiber, coiled and supported at 75mm diameter, in line with TIA/EIA-455-192 (FOTP-192). It can be seen that both coating types give very good polarization extinction ratio (PER) performance at high temperature up to 180oC, with better performance shown by one coating type on the low temperature side, since it does not harden to the same extent below 0oC. The long term thermal exposure effects will be discussed and experimental results presented which include testing the PER performance over temperature both before and after an extended period of high temperature endurance. This will demonstrate the relative merits of different styles of coatings. From the PER performance, the h-parameter of the fiber can be calculated and hence the preferred coating type selected and recommended for the customer operating environment.

Fabrication Routes for Continuous Fiber-Reinforced Ceramic Composites (CFCC)

NASA Technical Reports Server (NTRS)

DiCarlo, James A.; Bansal, Narottam P.

1998-01-01

The primary approaches used for fabrication of continuous fiber-reinforced ceramic composite (CFCC) components have been reviewed. The CFCC fabrication issues related to fiber, interface, and matrix have been analyzed. The capabilities, advantages and limitations of the five matrix-infiltration routes have been compared and discussed. Today, the best fabrication route for the CFCC end-user is not clear and compromises need to be made depending on the details of the CFCC application. However, with time, this problem should be reduced as research continues to develop advanced CFCC constituents and fabrication routes.

Fabrication Routes for Continuous Fiber-Reinforced Ceramic Composites (CFCC)

NASA Technical Reports Server (NTRS)

DiCarlo, James A.; Bansal, Narottam P.

1998-01-01

The primary approaches used for fabrication of continuous fiber-reinforced ceramic composite (CFCC) components have been reviewed. The CFCC fabrication issues related to fiber, interface, and matrix have been analyzed. The capabilities. advantages and limitations of the five matrix-infiltration routes have been compared and discussed. Today. the best fabrication route for the CFCC end-user is not clear and compromises need to be made depending on the details of the CFCC application. However, with time, this problem should be reduced as research continues to develop advanced CFCC constituents and fabrication routes.