2,760 research outputs found

    Borate based bioactive glass scaffolds for hard and soft tissue engineering

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    The main objectives of this dissertation were to evaluate bioactive borate glass scaffolds for hard and soft tissue applications and determine the potential toxicity of the borate glasses on the adjacent and systemic tissues. Porous randomly oriented fiber scaffolds composed of bioactive borate glass were implanted in subcutaneous soft tissue sites and in calvaria defects of laboratory rats and no signs of toxicity (necrotic tissue, increase in macrophages or other immune cells) were detected in any of the adjacent tissues (hard or soft). Systemic organs (kidney and liver) of laboratory rats implanted with bioactive borate scaffolds were analyzed for possible systemic toxicity and no adverse effects were found beyond normal incidental changes. Bone was found to grow statistically better (p\u3c0.05) in bioactive borate glass scaffolds when compared to similar scaffolds composed of borosilicate and silicate based bioactive glasses. For the first time, elements were added to a bioactive glass for the purposes of promoting angiogenesis. The elements copper and zinc were shown to significantly increase the number of blood vessels (p\u3c0.05) present in the soft tissue inside bioactive borate glass scaffolds when compared to the un-doped scaffolds. Bioactive borate glass fibers were also demonstrated as a new material that may be useful in the treatment of chronic wounds. A full thickness cutaneous defect (15mm diameter) on the back of a laboratory rats were healed in similar time (18 days), but with a higher quality scar than the control (untreated wound). The results from the full thickness cutaneous defect opens the door for new potential uses of bioactive borate glass fibers such as the treatment of chronic wounds and severe burns --Abstract, page v

    Wound Care

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    A method for treating a wound, and a dressing for wound care management comprising a three-dimensional body of glass-based fibers comprising one or more glass-formers selected from the group consisting of P2O5, SiO2, and B2O3; at least about 25 wt % of the fibers have a diameter between about 200 nm and about 4000 nm, and a length:width aspect ratio of at least about 10. In another form, the glasses are in the form of particles in an ointment or cream applied to a wound. In yet other forms the glasses are employed as fibers formed into sutures for closing a wound, or as particles in a surgical glue for closing a wound

    Controlling Calcium Compound Formation in Biocompatible Materials for Tissue Regeneration and Repair in Mammals

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    A biocompatible composition for tissue repair or regeneration in mammals comprising one or more glass former compounds selected from the group consisting of B2O3, P2O5, and SiO2 and director elements selected from the group consisting of Cu, Sr, Zn, Fe, Mn, Cr, V, Nb, Mo, W, Ba, Co, S, Al, Ti, Y, Mg, Si and/or Ni to promote in vivo calcium compound formation of calcium carbonate or other calcium compounds other than hydroxyapatite. Upon direct application of the biocompatible composition to a mammalian host, calcium carbonate or other calcium compounds other than hydroxyapatite form upon bioreaction of the composition with bodily fluids

    Scaffold for Bone and Tissue Repair in Mammals

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    A mammalian tissue scaffold and method for making a tissue scaffold including a rigid scaffold body of biocompatible glass fibers bonded together and in special alignment to define open channels within the scaffold to allow fluid flow into and within the scaffold

    Scaffold for Tissue Regeneration in Mammals

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    A three-dimensional scaffold with interconnected pores for repair of tissue comprising a scaffold body for structural support of the tissue scaffold, where the scaffold body comprises scaffold body components bonded to each other and made from component materials comprising about 40 to about 90 wt % B2O3, and two or more other oxides, wherein the scaffold body has a porosity between about 15 and about 90 vol %

    Prediction of strawberry yield based on receptacle detection and Bayesian inference

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    The receptacle of strawberry is a more direct part than the flower for predicting yield as they eventually become fruits. Thus, we tried to predict the yield by combining an AI technique for receptacle detection in images and statistical analysis on the relationship between the number of receptacles detected and the strawberry yield over a period of time. Five major cultivars were cultivated to consider the cultivar characteristics and environmental factors for two years were collected to consider the climate difference. Faster R–CNN based object detector was used to estimate the number of receptacles per strawberry plant in given two-dimensional images, which achieved a mAP of 0.6587 for our dataset. However, not all receptacles appear on the two-dimensional images, and Bayesian analysis was used to model the uncertainty associated with the number of receptacles missed by the AI. After estimating the probability of fruiting per receptacle, prediction models for the total strawberry yield at the end of harvest season were evaluated. Even though the detection accuracy was not perfect, the results indicated that counting the receptacles by object detection and estimating the probability of fruiting per receptacle by Bayesian modeling are more useful for predicting the total yield per plant than knowing its cumulative yield during the first month

    Hachimoji DNA and RNA: A genetic system with eight building blocks

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    Reported here are DNA and RNA-like systems built from eight (hachi-) nucleotide letters (-moji) that form four orthogonal pairs. This synthetic genetic biopolymer meets the structural requirements needed to support Darwinism, including a polyelectrolyte backbone, predictable thermodynamic stability, and stereoregular building blocks that fit a Schrödinger aperiodic crystal. Measured thermodynamic parameters predict the stability of hachimoji duplexes, allowing hachimoji DNA to double the information density of natural terran DNA. Three crystal structures show that the synthetic building blocks do not perturb the aperiodic crystal seen in the DNA double helix. Hachimoji DNA was then transcribed to give hachimoji RNA in the form of a functioning fluorescent hachimoji aptamer. These results expand the scope of molecular structures that might support life, including life throughout the cosmos

    Effects of nitroethane and 2-nitropropanol against Campylobacter jejuni

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    Campylobacter jejuni is an important foodborne pathogen that colonizes the gut of swine. In this study, the effects of nitroethane and 2-nitropropanol (0, 10 and 20 mM) on growth of C. jejuni were tested during culture in Bolton broth adjusted to pH of 5.6, 7.0 or 8.2. Viable cell counts of samples taken at intervals during incubation revealed main effects (P\u3c0.0001) of nitroethane or 2-nitropropanol on mean specific growth rates thus demonstrating that these were inhibitory to C. jejuni. By 48 h of incubation, C. jejuni concentrations had increased by 1.9 log10 CFU/ml or higher in cultures containing no added nitrocompound

    Imaging the Anisotropic Nonlinear Meissner Effect in Nodal YBa2_{2}Cu3_{3}O7−δ_{7-\delta} Thin-Film Superconductors

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    We have directly imaged the anisotropic nonlinear Meissner effect in an unconventional superconductor through the nonlinear electrodynamic response of both (bulk) gap nodes and (surface) Andreev bound states. A superconducting thin film is patterned into a compact self-resonant spiral structure, excited near resonance in the radio-frequency range, and scanned with a focused laser beam perturbation. At low temperatures, direction-dependent nonlinearities in the reactive and resistive properties of the resonator create photoresponse that maps out the directions of nodes, or of bound states associated with these nodes, on the Fermi surface of the superconductor. The method is demonstrated on the nodal superconductor YBa2_{2}Cu3_{3}O7−δ_{7-\delta} and the results are consistent with theoretical predictions for the bulk and surface contributions.Comment: 5 pages, 3 figures, Phys. Rev. Lett. (in press

    Physical activity, black carbon exposure and airway inflammation in an urban adolescent cohort

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    Objective Regular physical activity can improve cardiopulmonary health; however, increased respiratory rates and tidal volumes during activity may increase the effective internal dose of air pollution exposure. Our objective was to investigate the impact of black carbon (BC) measured by personal sampler on the relationship between physical activity and fractional exhaled nitric oxide (FeNO), a marker of airway inflammation. We hypothesized that higher personal BC would attenuate the protective effect of physical activity on airway inflammation. Methods We performed a cross-sectional study nested in a birth cohort of African American and Dominican children living in the Bronx and Northern Manhattan, New York City. Children were recruited based on age (target 9–14 year olds) and presence (n=70) or absence (n=59) of current asthma. Children wore wrist mounted accelerometers for 6 days and were classified as ‘active’ if they had ≥60 min of moderate-to-vigorous activity (MVA) each day and ‘non-active’ if they had <60 min of MVA on any given day, based on CDC guidelines. Personal BC measured using a MicroAeth, was assessed during two 24-h periods, at the beginning and end of physical activity assessment. High BC was defined as the upper tertile of BC measured with personal sampler. FeNO measurements were sampled at the beginning and end of the of physical activity assessment. Results In multivariable linear regression models, ‘active’ children had 25% higher personal BC concentrations (p=0.02) and 20% lower FeNO (p=0.04) compared to ‘non-active’ children. Among children with high personal BC (n=33), there was no relationship between activity and FeNO (p=1.00). The significant protective relationship between activity and airway inflammation was largely driven by children with lower personal BC (n=96, p=0.04). Conclusions Children that live in an urban environment and are physically active on a daily basis have higher personal exposure to BC. High BC offsets the protective relationship between physical activity and airway inflammation
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