332 research outputs found

    Effect of Exposure on the Mechanical Properties of Gamma MET PX

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    The effect of a service environment exposure on the mechanical properties of a high Nb content TiAl alloy, Gamma MET PX , was assessed. Gamma MET PX, like other TiAl alloys, experiences a reduction of ductility following high temperature exposure. Exposure in Ar, air, and high-purity oxygen all resulted in a loss of ductility with the ductility reduction increasing with oxygen content in the exposure atmosphere. Embrittling mechanisms, including bulk microstructural changes, moisture induced environmental embrittlement, and near surface effects were investigated. The embrittlement has been shown to be a near-surface effect, most likely due to the diffusion of oxygen into the alloy

    Serum neutrophil gelatinase-associated lipocalin as a biomarker of disease activity in pediatric lupus nephritis

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    Background: Neutrophil gelatinase-associated lipocalin (NGAL) is expressed in immature neutrophil precursors and in epithelial cells during both inflammation and neoplastic transformation. A recent prospective pediatric study demonstrated that concentrations of NGAL in urine and plasma represent novel, sensitive, and specific biomarkers for early identification of acute kidney injury following cardiac surgery. Objective: To assess the relationship of serum NGAL levels with disease activity in pediatric systemic lupus erythematosus (SLE) with special emphasis on lupus nephritis. Methods: The study included 30 children and adolescents with pediatric SLE with a mean age of 16.48±3.524 years. Patients were clinically and laboratory evaluated and categorized into those with nephritis and those without nephritis. Activity was assessed using SLEDAI score, NGAL levels were measured in the sera of included patients and were compared to those of 20 matched controls using ELISA. Results: Serum NGAL was significantly higher in SLE patients in comparison to the controls (z=-5.962, p < 0.001). Furthermore serum NGAL was significantly higher in SLE patients with nephritis and in those without nephritis in comparison to the controls (p < 0.001 in both). Serum NGAL was higher in SLE patients with nephritis in comparison to those without nephritis, yet the results are borderline regarding statistical significance (p=0.05). Levels of serum NGAL correlated significantly with disease activity as assessed by SLE disease activity index (SLEDAI) (r=0.485, p < 0.01). There was a significant correlation between serum NGAL and urinary protein to creatinine ratio, 24hr urinary protein and BUN of SLE patients. Conclusion: Our results suggest that serum NGAL represents a novel biomarker for disease activity in pediatric SLE patients, and a marker of severity of renal involvement.Keywords: SLE, NGAL, SLEDAI, lupus nephritisEgypt J Pediatr Allergy Immunol 2011;9(1):15-2

    Thymus algeriensis and Thymus fontanesii exert neuroprotective effect against chronic constriction injury-induced neuropathic pain in rats

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    We have previously demonstrated that the Thymus algeriensis and Thymus fontanesii extracts have powerful anti-inflammatory, antipyretic, and analgesic effects against acute pain models. We profiled their chemical composition and found many phenolic acids, flavonoids, and phenolic diterpenes. In this work, we investigated their antioxidant properties on HaCaT cells exposed to UVA-induced oxidative stress and examined their effects against chronic neuropathic pain and the underlying mechanisms. Through a rat chronic constriction injury (CCI) model, we induced chronic neuropathic pain by placing 4 loose ligatures around the right sciatic nerve for 14 days. Thermal and mechanical hyperalgesia in addition to cold and dynamic allodynia were tested on the day before surgery and on the 7th and 14th post-surgery days. Key markers of the nitrosative and oxidative stresses, in addition to markers of inflammation, were measured at day 14 post surgery. Histopathological examination and immunostaining of both synaptophysin and caspase-3 of sciatic nerve and brain stem were also performed. Results of this study showed that T. algeriensis extract suppresses UVA oxidative stress in HaCaT cells via activation of the Nrf-2 pathway. Both extracts attenuated hyperalgesia and allodynia at 7- and 14-days post-surgery with more prominent effects at day 14 of surgery. Their protective effects against neuropathic pain were mediated by inhibiting NOX-1, iNOS, by increasing the enzyme activity of catalase, and inhibition of inflammatory mediators, NF-κB, TNF-α, lipoxygenase, COX-2 enzymes, and PGE2. Furthermore, they improved deleterious structural changes of the brainstem and sciatic nerve. They also attenuated the increased caspase-3 and synaptophysin. The data indicate that both extracts have neuroprotective effects against chronic constriction injury-induced neuropathic pain. The observed protective effects are partially mediated through attenuation of oxidative and nitrosative stress and suppression of both neuroinflammation and neuronal apoptosis, suggesting substantial activities of both extracts in amelioration of painful peripheral neuropathy

    Penile Epidermal Inclusion Cyst

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    We report a case of epidermal inclusion cyst in a 32-year-old male. This was a complication of circumcision that was neglected over years to form stones and urethrocutaneous fistula. Complete excision of the cyst and repair of the fistula were performed successfully. Histopathological examination confirmed our diagnosis

    Elongated Wire-Like Zinc Oxide Nanostructures Synthesized from Metallic Zinc

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    Elongated wire-like Zinc oxide, nanocombs and nanocrystals have been successfully synthesized on the silicon substrate from the metallic zinc as a starting material. The annealing temperature was as low as 450 ºC in argon atmosphere mixed with about 3% oxygen. Structural analysis using the X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) showed that the existence of two phases; nanowires and crystalline form. Moreover some nanoparticles aggregates were noticed to be attached in the bulk to the sides of the ZnO nanocrystals and sometimes these aggregate attached to the Zinc oxide hexagonal crystal and grow to form nanowire at different angles. Scanning electron microscopy (SEM) investigations for the zinc oxide nanostructure on the silicon substrate showed the formation of the nanocrystals in the gas flow direction and at the low energy sites over the silicon substrate. Photoluminescence (PL) measurements, performed at the room temperature, showed the existence of two basic emissions: narrow ultraviolet (UV) emission at 398 nm which attributed to the near band edge emission of the wide band gap and a very wide, more intensive, green emission at 471 nm corresponds to the crystal defects such as vacancies, interstitial sites in ZnO

    The Therapeutic Potential of Anthocyanins : Current Approaches Based on Their Molecular Mechanism of Action

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    Anthocyanins are natural phenolic pigments with biological activity. They are well-known to have potent antioxidant and antiinflammatory activity, which explains the various biological effects reported for these substances suggesting their antidiabetic and anticancer activities, and their role in cardiovascular and neuroprotective prevention. This review aims to comprehensively analyze different studies performed on this class of compounds, their bioavailability and their therapeutic potential. An in-depth look in preclinical, in vitro and in vivo, and clinical studies indicates the preventive effects of anthocyanins on cardioprotection, neuroprotection, antiobesity as well as their antidiabetes and anticancer effects

    The use of visual methods to explore how children construct and assign meaning to the ''self'' within two urban communities in the Western Cape, South Africa

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    This study aimed to explore how children construct and assign meaning to the ''self'' within two urban communities of Cape Town in South Africa. Using a child participation methodological framework data were collected using Photovoice and community maps with 54 participants between the ages of 9 and 12. Feelings of safety, social connectedness, and children's spaces were found to be central to the ways in which the participants constructed and assigned meaning to the ''self.'' The study provides implications for intervention programmes aimed at improving children's well-being to be inclusive of activities aimed at improving children's self-concept, including the construction of safe spaces for children to play, learn, and form meaningful relationships

    Enzymatically Degradable Mussel-Inspired Adhesive Hydrogel

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    Mussel-inspired adhesive hydrogels represent innovative candidate medical sealants or glues. In the present work, we describe an enzyme-degradable mussel-inspired adhesive hydrogel formulation, achieved by incorporating minimal elastase substrate peptide Ala-Ala into the branched poly(ethylene glycol) (PEG) macromonomer structure. The system takes advantage of neutrophil elastase expression upregulation and secretion from neutrophils upon recruitment to wounded or inflamed tissue. By integrating adhesive degradation behaviors that respond to cellular cues, we expand the functional range of our mussel-inspired adhesive hydrogel platforms. Rapid (<1 min) and simultaneous gelation and adhesion of the proteolytically active, catechol-terminated precursor macromonomer was achieved by addition of sodium periodate oxidant. Rheological analysis and equilibrium swelling studies demonstrated that the hydrogel is appropriate for soft tissue-contacting applications. Notably, hydrogel storage modulus (G) achieved values on the order of 10 kPa, and strain at failure exceeded 200% strain. Lap shear testing confirmed the materials adhesive behavior (shear strength: 30.4 ± 3.39 kPa). Although adhesive hydrogel degradation was not observed during short-term (27 h) in vitro treatment with neutrophil elastase, in vivo degradation proceeded over several months following dorsal subcutaneous implantation in mice. This work represents the first example of an enzymatically degradable mussel-inspired adhesive and expands the potential biomedical applications of this family of materials

    Contribution to the understanding of tribological properties of graphite intercalation compounds with metal chloride

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    Intrinsic tribological properties of lamellar compounds are usually attributed to the presence of van der Waals gaps in their structure through which interlayer interactions are weak. The controlled variation of the distances and interactions between graphene layers by intercalation of electrophilic species in graphite is used in order to explore more deeply the friction reduction properties of low-dimensional compounds. Three graphite intercalation compounds with antimony pentachloride, iron trichloride and aluminium trichloride are studied. Their tribological properties are correlated to their structural parameters, and the interlayer interactions are deduced from ab initio bands structure calculations
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