919 research outputs found

    Current Implant Surface Technology: An Examination of Their Nanostructure and Their Influence on Fibroblast Alignment and Biocompatibility

    Get PDF
    Systematic reviews indicate that breast implant texture confers a protective effect on capsular contracture. Fibroblasts are affected by micro- and nanotopographies. Few previous studies have investigated the inherent topographies of existing breast implants and the surfaces with which body tissue is exposed. Aims: To examine currently available breast implant surfaces at high resolution and evaluate features within their surface that have been demonstrated to influence fibroblast alignment. Methods: Using scanning electron and light microscopy, 5 distinct smooth and textured silicone implants including the Mentor Siltex® (Mentor Corporation, Santa Barbara, Calif) and Allergan Biocell® (Allergan Medical Corporation, Santa Barbara, Calif) surfaces were investigated at high magnification to illustrate their intrinsic surface topographies. Results: The images obtained illustrate remarkable micro- and nanoscale topographies. Each surface produced a distinctive microenvironment capable of influencing cell shape and thus biointegration. These features are illustrated by our unique, high-magnification images. The smooth surface exhibits a shallow, regular, 5-µm period rippled texture that may explain higher reported contracture rates, while the Biocell and Siltex surfaces show 100- to 200-µm deep but random features that have been shown to anchor the implant to breast tissue and reduce contracture. Results allow a cell's eye view of these implants, with an explanation of why these types of topographies influence the success of these implants. Conclusions: We assessed commonly available silicone implants and offer a unique overview into their surface topographies and how they are manufactured. We conclude that these surfaces require modernization. Our findings provide further insight into potential interactions between cellular assemblies and artificial surfaces and may contribute to the development of improved implant surfaces

    Patterning of Novel Breast Implant Surfaces by Enhancing Silicone Biocompatibility, Using Biomimetic Topographies

    Get PDF
    Introduction and Aims: Silicone biocompatibility is dictated by cell-surface interaction and its understanding is important in the field of implantation. The role of surface topography and its associated cellular morphology needs investigation to identify qualities that enhance silicone surface biocompatability. This study aims to create well-defined silicone topographies and examine how breast tissue–derived fibroblasts react and align to these surfaces. Methods: Photolithographic microelectronic techniques were modified to produce naturally inspired topographies in silicone, which were cultured with breast tissue–derived human fibroblasts. Using light, immunofluorescent and atomic force microscopy, the cytoskeletal reaction of fibroblasts to these silicone surfaces was investigated. Results: Numerous, well-defined micron-sized pillars, pores, grooves, and ridges were manufactured and characterized in medical grade silicone. Inimitable immunofluorescent microscopy represented in our high magnification images of vinculin, vimentin, and the actin cytoskeleton highlights the differences in fibroblast adhesion between fabricated silicone surfaces. These unique figures illustrate that fibroblast adhesion and the reactions these cells have to silicone can be manipulated to enhance biointegration between the implant and the breast tissue. An alteration of fibroblast phenotype was also observed, exhibiting the propensity of these surfaces to induce categorical remodeling of fibroblasts. Conclusions: This unique study shows that fibroblast reactions to silicone topographies can be tailored to induce physiological changes in cells. This paves the way for further research necessary to develop more biocompatible constructs capable of eliminating capsular contracture by subverting the foreign body response

    Vibration Serviceability Assessment of a Historic Suspension Footbridge

    Get PDF
    Experimental and numerical studies for the structural and vibration serviceability assessment of a historic suspension footbridge adopting non-invasive surveys and low-cost equipment are presented. Field surveys have been carried out to determine geometric properties, ambient vibration tests have been performed to estimate the dynamic properties, and the dynamic response of the footbridge under the action of a single crossing pedestrian has been recorded. Based on field surveys, a 3D Finite Element model was built and was then calibrated against ambient vibration test results. The experimentally-measured maximum acceleration under the action of one crossing pedestrian is compared with the ones obtained numerically and analytically. Furthermore, vibration serviceability assessment under multi-pedestrian loading is carried out, adopting the simplified procedure recommended by a recent guideline. Results show that low-cost non-invasive dynamic testing is suitable to correctly identify the footbridge vertical natural frequencies and mode shapes, including higher-order ones, and to draw considerations about the state of degradation of the structure. Moreover, the level of vibration under the action of a single pedestrian can be estimated with sufficient accuracy using a simplified loading model, provided that the modal damping ratio is properly tuned

    Antibacterial activity of certain Iranian medicinal plants against methicillin-resistant and sensitive Staphylococcus aureus

    No full text
    Bacterial resistance to antibiotics is a serious global problem and includes strains of beta-lactam-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Novel antimicrobials and/or new approaches to combat the problem are urgently needed. The aim of this study was to investigate the antimicrobial activity of alcoholic and aqueous extract of 23 medical plants species of Golestan province on clinical and standard stains of MRSA and MSSA. Twenty three medicinal plants were collected from their natural habitat in Golestan province in north of Iran. Their ethanolic and aqueous extract obtained by percolation methods. Antibacterial effects were assessed by disk diffusion method and the Minimum Inhibitory Concentration (MIC) of the extracts was determined by the micro broth dilution against 14 clinical and standard strains of methicillin resistant and sensitive of Staphylococcus aureus. The ethanolic and aqueous extract of 8, 3 plants showed best anti staphylococcal effect, respectively. The ethanolic extract of Artemisia, herbaalba, Nigella sativa, Punica granatum, possed the most outstanding in vitro antibacterial activity which the maximum inhibition zone was 22.4-18 mm, respectively and the lowest MIC values was measured in Punica granatum, as 0.01 mg mL-1 against MRSA The results showed that ethanolic extract had better antibacterial effect than aqueous extract and anti staphylococcal activity of Ethanolic extract of plants against MRSA was better than MSSA strains. Ethanolic and aqueous extract of Punica granatum had the best antibacterial activity against the tested microorganisms. The result obtained from these plants might be considered sufficient for further studies. © 2006 Asian Network for Scientific Information

    A dietary intervention for chronic diabetic neuropathy pain: a randomized controlled pilot study

    Get PDF
    Background: Diabetic neuropathy is a common and often debilitating condition for which available treatments are limited. Because a low-fat plant-based diet has been shown to improve glycemic control in individuals with type 2 diabetes, we hypothesized that such a diet would reduce painful symptoms of diabetic neuropathy. Methods: In this 20-week pilot study, individuals with type 2 diabetes and painful diabetic neuropathy were randomly assigned to two groups. The intervention group was asked to follow a low-fat, plant-based diet, with weekly classes for support in following the prescribed diet, and to take a vitamin B12 supplement. The control group was asked to take the same vitamin B12 supplement, but received no other intervention. At baseline, midpoint and 20 weeks, clinical, laboratory and questionnaire data were collected. Questionnaires included an analog ‘worst pain’ scale, Michigan Neuropathy Screening Instrument, global impression scale, Short Form McGill Pain Questionnaire, Neuropathy Total Symptom Score, a weekly pain diary and Norfolk Quality of Life Questionnaire. Results: After 20 weeks, body weight change with the intervention was −6.4 kg (95% confidence interval (CI) −9.4 to −3.4, PP=0.03) with the intervention in an effect size analysis. The between-group difference in change in pain, as measured by the McGill pain questionnaire, was −8.2 points (95% CI −16.1 to −0.3, P=0.04). Michigan Neuropathy Screening Instrument questionnaire score change was −1.6 points (95% CI −3.0 to −0.2, P=0.03). Conclusions: Improvements were seen in some clinical and pain measures. This pilot study suggests the potential value of a plant-based diet intervention, including weekly support classes, for treating painful diabetic neuropathy

    The frequency of transforming growth factor-TGF-B gene polymorphisms in a normal southern Iranian population

    Get PDF
    Several single nucleotide polymorphisms (SNPs) of the transforming growth factor-β1 gene (TGFB1) have been reported. Determination of TGFB1 SNPs allele frequencies in different ethnic groups is useful for both population genetic analyses and association studies with immunological diseases. In this study, five SNPs of TGFB1 were determined in 325 individuals from a normal southern Iranian population using polymerase chain reaction-restriction fragment length polymorphism method. This population was in Hardy-Weinberg equilibrium for these SNPs. Of the 12 constructed haplotypes, GTCGC and GCTGC were the most frequent in the normal southern Iranian population. Comparison of genotype and allele frequencies of TGFB SNPs between Iranian and other populations (meta-analysis) showed significant differences, and in this case the southern Iranian population seems genetically similar to Caucasoid populations. However, neighbour-joining tree using Nei's genetic distances based on TGF-β1 allele frequencies showed that southern Iranians are genetically far from people from the USA, Germany, UK, Denmark and the Czech Republic. In conclusion, this is the first report of the distribution of TGFB1 SNPs in an Iranian population and the results of this investigation may provide useful information for both population genetic and disease studies. © 2008 The Authors

    Productivity of various barley (Hordeum vulgare L.) cultivars under semi-arid conditions in southern Russia

    Get PDF
    ArticleDrought is a significant factor limiting crop production in arid conditions. In the dry climatic weather situation of southern Russia, ten - year laboratory trials and subsequent field experiments were laid out on various barley varieties collected across the globe during 2007 – 2017 period. This study was conducted to ascertain from the collection of barley cultivars of the entire world which one is best suited to stressful climatic conditions by being tolerant to drought, heat and salinity which can be adopted for barley breeding. According to the results obtained, the varieties that are tolerant to dry climatic conditions are as follows: Alga (Lithuania), Brenda, Henni (Germany), Décor (Great Britain), Furat 5 (Syria), Vakula (Ukraine), Ataman (Belarus) and Vladimir (Russia); heat resistant varieties are: Brenda (Germany), Alga (Lithuania), Furat 5 (Syria), Ataman (Belarus) , Vladimir and Ratnik (Russia); Salt - resistant varieties: Alga (Lithuania), Henni (Germany) and Vladimir (Russia). The selected varieties did not show any sign of adverse weather effect resulting in stable grain productivity throughout the entire duration of this research over the years, they had large grain size and stable 1 , 000 grains weight. However, the yield of selected cultivars varied over the years which was about 1.1 – 1.4 t ha - 1

    A general algorithm for manipulating non-linear and linear entanglement witnesses by using exact convex optimization

    Full text link
    A generic algorithm is developed to reduce the problem of obtaining linear and nonlinear entanglement witnesses of a given quantum system, to convex optimization problem. This approach is completely general and can be applied for the entanglement detection of any N-partite quantum system. For this purpose, a map from convex space of separable density matrices to a convex region called feasible region is defined, where by using exact convex optimization method, the linear entanglement witnesses can be obtained from polygonal shape feasible regions, while for curved shape feasible regions, envelope of the family of linear entanglement witnesses can be considered as nonlinear entanglement witnesses. This method proposes a new methodological framework within which most of previous EWs can be studied. To conclude and in order to demonstrate the capability of the proposed approach, besides providing some nonlinear witnesses for entanglement detection of density matrices in unextendible product bases, W-states, and GHZ with W-states, some further examples of three qubits systems and their classification and entanglement detection are included. Also it is explained how one can manipulate most of the non-decomposable linear and nonlinear three qubits entanglement witnesses appearing in some of the papers published by us and other authors, by the method proposed in this paper. Keywords: non-linear and linear entanglement witnesses, convex optimization. PACS number(s): 03.67.Mn, 03.65.UdComment: 37 page

    Effect of early vestibular rehabilitation on vertigo and unsteadiness in patients with acute and sub-acute head trauma

    Get PDF
    Introduction: Vestibular rehabilitation is a treatment option for the management of vertigo and unsteadiness, which are very common in head trauma patients and more challenging in the early months after trauma. This study evaluated the effectiveness of a vestibular rehabilitation program in the recovery of acute and sub-acute head trauma patients. The goal of this study was evaluation of the effect of early vestibular rehabilitation on patients with acute and sub-acute head trauma. Materials and Methods: This study was performed in 20 head trauma patients with vertigo and unsteadiness. The patients were randomly divided into two groups: one group received medical therapy (Betaserc) and the other received rehabilitation and medical therapy. An individualized vestibular rehabilitation program was designed that was then revised and verified by a joint committee of vestibular rehabilitation groups. The effectiveness of interventions was measured using the Dizziness Handicap Inventory (DHI) by comparing the results before and after therapy. Results: The physical conditions and DHI scores of patients in both groups were similar at baseline. After 1 month of rehabilitation, patients receiving vestibular rehabilitation and medication showed greater progress than patients receiving medication only (P=0.000). Conclusion: Vestibular rehabilitation can aid in the recovery from vertigo and increase the stability of head trauma patients. Simultaneous treatment with medicine and vestibular rehabilitation exercises can result in quicker and better therapeutic effects. © Iranian Journal of Otorhinolaryngology. 2018
    corecore