Severe plastic deformation: Nanostructured materials, metal-based and polymer-based nanocomposites: A review.

Significant deformation of the metal structure can be achieved without breaking or cracking the metal. There are several methods for deformation of metal plastics. The most important of these methods are angular channel pressing process, high-pressure torsion, multidirectional forging process, extrusion-cyclic compression process, cumulative climbing connection process, consecutive concreting and smoothing method, high-pressure pipe torsion. The nanocomposite is a multiphase material which the size of one of its phases is less than 100 nm in at least one dimension. Due to some unique properties, metal-based nanocomposites are widely used in engineering applications such as the automotive and aerospace industries. Polymer-based nanocomposites are two-phase systems with polymer-based and reinforcing phases (usually ceramic). These materials have a simpler synthesis process than metal-based nanocomposites and are used in a variety of applications such as the aerospace industry, gas pipelines, and sensors. Severe plastic deformation (SPD) is known to be the best method for producing bulk ultrafine grained and nanostructured materials with excellent properties. Different Severe plastic deformation methods were developed that are suitable for sheet and bulk solid materials. During the past decade, efforts have been made to create effective Severe plastic deformation processes suitable for producing cylindrical tubes. In this paper, we review Severe plastic deformation processes intended to nanostructured tubes, and their effects on material properties and severe plastic deformation is briefly introduced and its common methods for bulk materials, sheets, and pipes, as well as metal background nanocomposites, are concisely introduced and their microstructural and mechanical properties are discussed. The paper will focus on introduction of the tube Severe plastic deformation processes, and then comparison of them based on their advantages and disadvantages from the viewpoints of processing and properties.

Application of multi-extruded fuel injectors for mixing enhancement of hydrogen gas at scramjet engine: computational study.

Scramjet engines are considered a highly promising technology for improving high-speed flight. In this study, we investigate the effects of using multi-extruded nozzles on fuel mixing and distribution inside the combustion chamber at supersonic flow. Additionally, we explore the impact of an inner air jet on fuel mixing in annular nozzles. To model fuel penetration in the combustor, we employ a computational technique. Our study compares the roles of three different extruded injectors on fuel diffusion and distribution at supersonic cross-flow. Our findings reveal that the use of an inner air jet increases fuel mixing in the annular jet, while the use of extruded nozzles improves fuel distribution by enhancing the vortices between injectors. These results demonstrate the potential benefits of incorporating multi-extruded nozzles and inner air jets in the design of scramjet engines.

Fuel mixing enhancement of transverse coaxial air and fuel jet by upstream shock wave on in scramjet engines: numerical study.

In this study, computational fluid dynamics (CFD) is used to disclose the impacts of upstream shock waves on fuel mixing of cross coaxial air and fuel jet at a scramjet engine. This study has tried to investigate the impact of three different lobe injectors (2-lobe, 3-lobe, and 4-lobe nozzle) on the fuel penetrations along the scramjet combustor. The supersonic air stream is M = 4 while cross hydrogen and air jet are released in sonic velocity. This study uses CFD simulations to analyze the effects of upstream shock waves on fuel mixing in the transverse coaxial jet and assess their potential for improving combustion efficiency. The results demonstrate that the usage of upstream shock waves significantly increases shock interactions and augments the vortex region downstream of the jet. Our results show that the impacts of shock waves on the penetration of fuel jet released from the coaxial lobe nozzle are substantial.

Rifampicin resistance in Mycobacterium tuberculosis in Iran: a two-centre study.

Multidrug-resistant tuberculosis remains a challenge. In this study, we investigated the incidence of rifampicin (RIF) resistance in Mycobacterium tuberculosis in a large number of pulmonary specimens. A two-center study in Tehran, the capital of Iran, was performed with 6624 pulmonary samples of patients with tuberculosis (TB) who were subjected to detection of RIF-resistant TB by GeneXpert MTB/RIF assay between May 2014 and July 2018. Conventional drug susceptibility testing was performed to confirm the results. Xpert MTB/RIF identified a total of 96 positives for M. tuberculosis, of which 5 (5.3%) samples were found to be RIF-resistant TB. All RIF-resistant and sensitive isolates detected by GeneXpert were phenotypically confirmed by drug susceptibility testing. These results indicated that the Xpert MTB/RIF test can be used as a rapid diagnostic method and can potentially decrease the morbidity associated with diagnostic delay and mistreatment.

Circular RNAs as important players in human gastric cancer

Circular RNAs as important players in human gastric cancer (AU)

Circular RNAs as important players in human gastric cancer.

As one of the most prevalent gastrointestinal diseases, gastric cancer (GC) is the second leading cause of cancer-related deaths worldwide. Since GC has no clinical manifestations in the early stage of the disease, most patients are detected in the later phases of disease and have an unfortunately lower chance of recovery. Circular RNAs (circRNAs), a novel category of non-coding RNAs (ncRNAs), are mainly engaged in the regulation of gene expression at the transcriptional and post-transcriptional levels. Numerous evidences have revealed that circRNAs play key roles in GC as they are involved in cell proliferation, growth, and apoptosis via modulating the expression of some target genes, miRNAs, and proteins. Many studies have addressed the impact of circRNA dysregulation on GC initiation, progression, and invasion via binding to miRNAs or RNA binding proteins. Moreover, changes in circRNA expression are associated with pathological and clinical features of GC highlighting their potentials as diagnostic or prognostic biomarkers in GC. In the current study, the recent findings on the significance of circRNAs in the development and progression of GC are reviewed. We focus on the implications of circRNAs as potential diagnostic or prognostic biomarkers in this malignancy.

Improved microstructure and mechanical properties in gas tungsten arc welded aluminum joints by using graphene nanosheets/aluminum composite filler wires.

In the present study, different amounts of graphene nanosheets (GNSs) were added to the 4043 aluminum alloy powders by using the mechanical alloying method to produce the composite filler wires. With each of the produced composite filler wires, one all-weld metal coupon was welded using the gas tungsten arc (GTA) welding process. The microstructure, mechanical properties and fracture surface morphology of the weld metals have been evaluated and the results are compared. As the amount of GNSs in the composition of filler wire is increased, the microstructure of weld metal was changed from the dendritic structure to fine equiaxed grains. Furthermore, the tensile strength and microhardness of weld metal was improved, and is attributed to the augmented nucleation and retarded growth. From the results, it was seen that the GNSs/Al composite filler wire can be used to improve the microstructure and mechanical properties of GTA weld metals of aluminum and its alloys.

Behavior of heptavalent technetium in sulfuric acid under α-irradiation: structural determination of technetium sulfate complexes by X-ray absorption spectroscopy and first principles calculations.

The effect of α-radiolysis on the behavior of heptavalent technetium has been investigated in 13 and 18 M H2SO4. Irradiation experiments were performed using α-particles ((4)He(2+), E = 68 MeV) generated by the ARRONAX cyclotron. UV-visible and X-ray absorption fine structure spectroscopic studies indicate that Tc(VII) is reduced to Tc(V) under α-irradiation. Extended X-ray absorption fine structure (EXAFS) spectroscopy measurements are consistent with the presence of mononuclear technetium sulfate complexes. Experimental results and density functional calculations show the formation of [TcO(HSO4)3(H2O)(OH)](-) and/or [TcO(HSO4)3(H2O)2] and [Tc(HSO4)3(SO4)(H2O)] and/or [Tc(HSO4)3(SO4)(OH)](-) for 13 and 18 M H2SO4, respectively.

A new technique for the strengthening of aluminum tungsten inert gas weld metals: using carbon nanotube/aluminum composite as a filler metal.

The effect of multi-walled carbon nanotube (MWCNT) on the mechanical properties of aluminum multipass weld metal prepared by the tungsten inert gas (TIG) welding process was investigated. High energy ball milling was used to disperse MWCNT in the aluminum powder. Carbon nanotube/aluminum composite filler metal was fabricated for the first time by hot extrusion of ball-milled powders. After welding, the tensile strength, microhardness and MWCNT distribution in the weld metal were investigated. The test results showed that the tensile strength and microhardness of weld metal was greatly increased when using the filler metal containing 1.5 wt.% MWCNT. Therefore, according to the results presented in this paper, it can be concluded that the filler metal containing MWCNT can serve as a super filler metal to improve the mechanical properties of TIG welds of Al and its alloys.

Prophylactic and therapeutic effects of garlic extract on Nerium oleander-induced arrhythmia: a new approach to antiarrhythmic therapy in an ovine model.

CONTEXT: Oleander is a potent cardiotoxic plant and is a common cause of poisoning in human and animals. There is no affordable and cost-effective treatment for oleander poisoning. Objective. To evaluate the prophylactic and therapeutic effects of garlic extract (Allium sativum) on Nerium oleander (a potent cardiotoxic plant) intoxication in sheep. MATERIALS AND METHODS: Eight sheep were intravenously infused with an unsterilized hydro-ethanol extract of garlic (50 mg/kg) before or after receiving a lethal dose of dried leaves (as a powder) of oleander (100 mg/kg, orally). The cardiac rhythm was continuously monitored using biopotential wireless transmitters and telemetry system. For evaluation of therapeutic effects, six sheep received the lethal dose of oleander and were administered with garlic extract after development of cardiac arrhythmias. Subsequently, the survived animals from the therapeutic study (four sheep) were administered with oleander without receiving any medication. Some blood constituents, including total antioxidant capacity, malondialdehyde, and troponin I, were compared between treated and untreated animals. RESULTS: Pretreatment with garlic extract reversed the arrhythmia caused by oleander to its previous normal rhythm in seven sheep, but, one sheep died of ventricular fibrillation. On therapeutic treatment, four sheep survived while two died of ventricular fibrillation. Dosing with oleander without receiving garlic extract resulted in death of all sheep due to ventricular fibrillation. Blood constituents did not show any significant changes between treated and untreated sheep, and before and after intoxication. CONCLUSIONS: Garlic extract reduced the case fatality from 100% to 12.5% and 33.3% as a prophylactic or therapeutic agent, respectively. Additionally, garlic extract delayed the time of onset of arrhythmias and prolonged the interval between intoxication and death of the animals. Garlic extract could be considered to be a potential and affordable antidote in oleander poisoning. However additional studies with a larger sample size and in other species need to be performed to confirm the results in this study.

Effect of Ti-containing inclusions on the nucleation of acicular ferrite and mechanical properties of multipass weld metals.

In the present study, the influence of Ti-containing inclusions on the development of acicular ferrite microstructure and mechanical properties in the multipass weld metals has been studied. Shielded metal arc weld deposits were prepared by varying titanium content in the range of 0.003-0.021%. The variation in the titanium content was obtained by the addition of different amounts of titanium oxide nanoparticles to the electrode coating. The dispersion of titanium oxide nanoparticles, composition of inclusions, microstructural analysis, tensile properties and Charpy impact toughness were evaluated. As the amount of Ti-containing inclusions in the weld metal was increased, the microstructure of the weld metal was changed from the grain boundary allotriomorphic ferrite structure to acicular ferrite with the intragranular nucleation of ferrite on the Ti-containing inclusions, and the mechanical properties were improved. This improvement is attributable to the increased percentage of acicular ferrite due to the uniform dispersion of Ti-containing inclusions and the pinning force of oxide nanoparticles against the growth of allotriomorphic ferrite and Widmanstätten ferrite from the austenite grain boundaries.

Serum level of matrix metalloproteinase-3 in patients with oral lichen planus.

BACKGROUND: Oral Lichen planus (OLP) is a chronic lesion of the oral mucosa with unknown origin. Basement membrane changes are common in OLP and may be mediated by proteases such as matrix metalloproteinase (MMPs) and mast cell chymase. The aim of our study was to evaluate the level of serum MMP-3 in OLP com-pared to normal individuals and assess its clinical significance. METHODS: Thirty four serum samples from patients diagnosed with OLP (12 males, 22 females, age: 42.2±10.8 years) and 34 serum samples from healthy control subjects (11 males, 23 females, age: 42.5±13.3 years) were collected and MMP-3 concentration was measured by ELISA. RESULTS: The serum MMP-3 level in OLP patients was higher (21.64±24.31 ng/ml) compared with healthy con-trols (16.52±23.63 ng/ml), but showed no statistically significant difference. A statistically significant difference was demonstrated between the two types of OLP, being more pronounced in the erosive/atrophic form 6). CONCLUSION: The different clinical appearances of OLP are associated with significant differences in MMP-3 serum level.

Serum levels of interleukins 4 and 10 in head and neck squamous cell carcinoma.

OBJECTIVE: There is currently controversy over the association between serum interleukin-4 and -10 levels and head and neck squamous cell carcinoma in patients of different ethnicity. This study aimed to investigate serum levels of these cytokines in Iranian patients with this pathology, and to analyse correlations with tumour location and tumour stage at diagnosis. DESIGN: Serum cytokines levels were quantified using commercial enzyme-linked immunosorbent assays. SUBJECTS: Study groups comprised 93 untreated patients and 53 healthy donors. RESULTS: Serum interleukin-4 levels were significantly increased in patients compared with controls (p < 0.000), but were not significantly associated with tumour stage. Serum interleukin-10 levels were not raised in patients, nor associated with tumour stage. CONCLUSION: Serum levels of interleukin-4, but not -10, were increased in Iranian head and neck squamous cell carcinoma patients. These data do not support an association of these cytokines with tumour progression; this is consistent with previous findings.

p 53 codon 72 polymorphism in stomach and colorectal adenocarcinomas in Iranian patients.

BACKGROUND: The association of a functional single nucleotide polymorphism at codon 72 of the p53 gene (Arg72Pro) with malignancy is a subject of controversy. We analyzed this polymorphism in 224 patients with gastrointestinal cancers (92 with stomach cancer and 132 with colorectal cancer) and in 163 healthy controls. MATERIAL AND METHODS: DNA was extracted from peripheral blood mononuclear cells and amplified with an allele-specific polymerase chain reaction. RESULTS: There was no significant association between p53 alleles and gastrointestinal cancers. The frequency of the Arg allele was 59.7, 58.8, and 59.2% in the stomach cancer patients, colorectal cancer patients, and controls, respectively. Frequencies of the Pro allele were 40.3% in patients with stomach cancer, 41.2% in patients with colorectal cancer, and 40.8% in controls. Likewise, genotype frequencies did not differ significantly between the two patient groups and controls. There were no differences in genotype or allele frequencies by gender, age, or histological grade. CONCLUSIONS: The data do not support the association of the p53 codon 72 polymorphism with stomach or colorectal cancers in Iranian patients.

Radiolytic yield of U(IV) oxidation into U(VI): a new mechanism for U(V) reactivity in acidic solution.

The yields of the radiolytic oxidation of U(IV) and of the U(VI) formation, measured by spectrophotometry, are found to be the same (G(-U(IV))(N2O) = G(U(VI))(N2O) = 8.4 x 10(-7) mol J(-1)) and almost double the H(2) formation yield (G(H(2)) = 4.4 x 10(-7) mol J(-1)) in the (60)Co gamma radiolysis of N(2)O-aqueous solutions in the presence of 2 mol L(-1) Cl(-) at pH = 0 (HCl). According to the mechanism of U(IV) radiolytic oxidation, we show that under the conditions of our experiments the U(V) ions do not disproportionate, but undergo a stoichiometric oxidation into U(VI) by H(+) with forming H(2).

CSF levels of cytokines in neuro-Behçet's disease.

BACKGROUND: Neurological manifestations of Behçet's disease (neuro-Behçet's disease) present in 5-30% of patients. Although cytokines play a pivotal role in pathogenesis of Behçet's disease, published studies about the cerebrospinal fluid (CSF) levels of cytokines in neuro-Behçet's disease are scanty. METHODS: Nine patients with active parenchymal, one patient with non-parenchymal neuro-Behçet's disease, six patients with headache attributed to Behçet's disease, 13 patients with viral meningitis, and 19 healthy controls were recruited. Interleukin 6, 8, 10, tumor necrotic factor-alpha, and interferon-gamma were measured in the CSF using enzyme-linked immunosorbent assay method. RESULTS: Patients with viral meningitis had significantly higher levels of all investigated cytokines except for interferon-gamma in comparison with the patients with parenchymal neuro-Behçet's disease, headache attributed to Behçet's disease and controls (P values <0.05). CSF interleukin 6 was significantly higher in patients with parenchymal neuro-Behçet's disease in comparison with the controls (P=0.025). CSF levels of investigated cytokines had no significant difference between patients with headache attributed to Behçet's disease and controls (P values >0.05). Patients with headache attributed to BD and patients with parenchymal NBD had no significant difference in measured cytokines (P values >0.05). CONCLUSION: In contrast to some previous studies, our investigation showed loss of analogy between CSF cytokine profiles of patients with parenchymal neuro-Behçet's disease and viral meningitis. Also we postulated a crucial role for interleukin 6 in immunopathogenesis of neuro-Behçet's disease.

Aqueous solution of UCl6(2-) in O2 saturated acidic medium: an efficient system to scavenge all primary radicals in spurs produced by irradiation.

Absorbance measurements find the yield of the oxidation of U(IV) to be (8.75 +/- 0.05) x 10(-7) mol J(-1) in the (60)Co gamma radiolysis of aqueous solutions containing 4.4 x 10(-3) mol L(-1) U(IV) in the presence of O(2) saturated 2 mol L(-1) Cl(-) at pH = 0. This high value of oxidation yield suggests that all primary radicals formed by water decomposition are scavenged in these solutions. Simulations using a nonhomogeneous stochastic kinetic track model agree with the experimental results and are used to explain the mechanism for scavenging radicals and oxidation of U(IV).

Expression of neuronal nitric oxide synthase during embryonic development of the rat optic vesicle.

The expression of neuronal nitric oxide synthase during the development of rat optic vesicle from embryonic day E14 to E18 was analyzed by histochemical procedures. The samples were frozen and cut on a cryostat and then studied by using the light microscope. Expression of nNOS was first seen on E14 in cells of Cajal-Retzius located in the marginal zone of optic vesicle. NADPH-d persisted in this layer throughout the embryonic period and began to decrease on E20. At E16, the optic vesicle has four NADPH-d positive layers. At E18, NADPH-d reactivity observed at low magnification showed five clearly defined layers. In the late stages, the most notable feature was a decrease in histochemical reaction of the marginal zone and at these stages, the layer IV showed less staining than the rest of the cortical plate. The observations suggest that nitric oxide is synthesized during embryonic life processes and this is related to maturational processes.

Pedicular vascular control in laparoscopic living donor nephrectomy: The use of clips instead of stapler in 341 donors.

PURPOSE: To demonstrate a less expensive approach for laparoscopic donor nephrectomy. MATERIALS AND METHODS: Left donor nephrectomy was done transperitoneally in flank position. Renal vein and artery were exposed and prepared for nephrectomy. Nondisposable trocars and instruments were used. The adrenal vein was clipped and its arteries were bipolar coagulated. Both renal artery and vein were clip-ligated using three medium large nonautomatic metallic clips and divided, instead of using rather expensive vascular endostapler. Kidney was hand-extracted from suprapubic incision (no Endobag was used). RESULTS: Donor nephrectomy was performed in 341 donors. Mean warm ischemia time was 8.17 minutes. Mean operative time was 260.3 minutes. Conversion and reoperation was required in 2.1% and 3.8% of donors, respectively. Ureteral complications were observed in 2.1% of recipients. No vascular accident occurred from pedicular vessels. One-year graft survival in recipients was 92.6%. By this approach, at least $600 was saved in each nephrectomy. CONCLUSION: Laparoscopic donor nephrectomy can be performed with a less expensive setup without adverse effects on graft outcome. Vascular control using nonautomatic clips instead of more costly vascular endostapler and also hand extraction of the kidney is safe, practical, and economical.

Living unrelated versus living related kidney transplantation: 20 years' experience with 2155 cases.

PURPOSE: To compare the long-term results of kidney transplantation from living unrelated donors (LURDs) with that from living related donors (LRDs). MATERIALS AND METHODS: From 1984 to 2004, we performed 2155 kidney transplantations of which 374 were from LRDs and 1760 from LURDs. We reviewed and compared the long-term data from these cases. RESULTS: The LURD group included 64.2% men with an overall mean age of 33.46 +/- 14.61 (range 3 to 76) years. Laparoscopic donor nephrectomy was performed in 329 cases (18.7%) with mean follow-up of 45.68 +/- 46.80 months. The LRD group included 66.5% of male recipients with overall mean age of 28.97 +/- 9.58 (range 9 to 65) years. Laparoscopic donor nephrectomy was performed in 12 cases (3.2%) of LRDs with mean follow-up of 81.15 +/- 67.03 months. One-, 3-, 5-, 10-, and 15-year graft survivals among LRDs were 91.6%, 81.7%, 76.4%, 64.4%, and 48.4%; and for LURDs, 91.5%, 86.7%, 81.4%, 68.2%, and 53.2%, respectively (P = .07). Patient survivals for 1, 3, 5, 10, and 15 years in LRDs were 94.6%, 91.9%, 83%, 79.5%, and 73.9%, and in LURDs were 93.6%, 91.7%, 89.3%, 84%, and 76.4%, respectively (P = .14). CONCLUSION: The results of living unrelated kidney transplantation upon long-term follow-up with a large number of cases were as good as living related kidney transplantation. The organ shortage can be alleviated by using living unrelated kidney transplantation. To our knowledge this is the largest experience with long-term follow-up reported from one center to date.