1,246 research outputs found

    Dynamic specification of vowels in Hijazi Arabic

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    \ua9 2024 De Gruyter Mouton. All rights reserved.Research on various languages shows that dynamic approaches to vowel acoustics – in particular Vowel-Inherent Spectral Change (VISC) – can play a vital role in characterising and classifying monophthongal vowels compared with a static model. This study’s aim was to investigate whether dynamic cues also allow for better description and classification of the Hijazi Arabic (HA) vowel system, a phonological system based on both temporal and spectral distinctions. Along with static and dynamic F1 and F2 patterns, we evaluated the extent to which vowel duration, F0, and F3 contribute to increased/decreased discriminability among vowels. Data were collected from 20 native HA speakers (10 females and 10 males) producing eight HA monophthongal vowels in a word list with varied consonantal contexts. Results showed that dynamic cues provide further insights regarding HA vowels that are not normally gleaned from static measures alone. Using discriminant analysis, the dynamic cues (particularly the seven-point model) had relatively higher classification rates, and vowel duration was found to play a significant role as an additional cue. Our results are in line with dynamic approaches and highlight the importance of looking beyond static cues and beyond the first two formants for further insights into the description and classification of vowel systems

    Proteomics: an evolving technology in Laboratory Medicine

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    The rapid developments in both genomics and proteomicswill allow scientists to define the molecular pathways in normal anddiseased cells. With these models, researchers will have the ability topredict previously unknown interactions and verify such predictionsexperimentally. Novel proteins, cellular functions, and pathways will alsobe unravelled. It is hoped that understanding the connections betweencellular pathways and the ability to identify their associated biomarkerswill greatly reduce the suffering and loss of life due to diseases.KEY WORDS: Proteomics; Laboratory medicin

    COMPARATIVE BIOAVAILABILITY (BIOEQUIVALENCE) STUDY FOR FIXED DOSE COMBINATION TABLET CONTAINING AMLODIPINE, VALSARTAN, AND HYDROCHLOROTHIAZIDE USING A NEWLY DEVELOPED HPLC-MS/MS METHOD

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    Objective: The aim of the study was to evaluate the bioequivalence between a newly developed generic tablet containing fixed-dose combination of amlodipine besylate, valsartan and hydrochlorothiazide (10/160/25 mg), and the reference brand product Exforge HCT® tablet; using a newly developed HPLC-MS/MS method for simultaneous determination of these drugs in human plasma.Methods: The brand (reference) and the test (generic) products were administered to thirty-nine healthy subjects. A fasting, laboratory blind, single-dose, two-treatment, two-period, two-sequence, randomized crossover design was conducted with 14 d washout period between dosing. Serial blood samples were withdrawn from each subject immediately before dosing (zero time), and then at 0.33, 0.66, 1.0, 1.33, 1.66, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 11, 12, 14, 16, 24, 48 and eventually at 72 h post dosing. Plasma samples were analyzed for simultaneous determination of amlodipine, valsartan and hydrochlorothiazide by a newly developed HPLC coupled with MS/MS detector. The linearity of the method was established for plasma concentration ranges of 0.2-12 ng/ml, 50-8000 ng/ml, and 2-250 ng/ml for amlodipine, valsartan, and hydrochlorothiazide, respectively.Results: Plasma concentration-time data of each individual were analyzed by non-compartmental method to measure the pharmacokinetics parameters; Cmax, Tmax, AUC0-t, AUC0-¥, lZ, T1/2. For amlodipine truncated AUC72hr was calculated. The 90% confidence interval for the pharmacokinetic parameters used for bioequivalence evaluation (Cmax and AUC) for amlodipine, valsartan, and hydrochlorothiazide were well within FDA acceptable ranges of 80-125%.Conclusion: It is concluded that the newly devolved generic product is bioequivalent with the brand product Exforge HCT® tablet. Thus, both products are clinically interchangeable.Keywords: Amlodipine, Valsartan, Hydrochlorothiazide, Pharmacokinetics, Bioequivalence, HPLC-MS/M

    Modelling the Portevin-Le Chatelier effects in aluminium alloys

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    Plastic deformation processes are among the most demanding processes in manufacturing causing different microstructure feature in materials. A number of various dislocation patterns can be induced by plastic strain under different conditions. A serrated yielding/jerky flow in some dilute alloys like aluminium-magnesium alloys during plastic deformation is a well-known phenomenon under certain regimes of strain rate and temperature reported in a significant number of works. The serrated features in these materials are so-called the Portevin-Le Chatelier effects. The occurrence of these undesirable effects is due to the interaction between solute atoms and mobile dislocation during the plastic deformation which is known as dynamic strain ageing. There are a significant number of theoretical and numerical investigations that have been focused on describing the serrated behaviour of these materials during plastic deformation. Hence, the fundamental objective of this paper is a general review of different constitutive modelling in regards with this feature. The typical material models and new constitutive models describing this feature are presented. In addition, applications of the models are provided indicating their advantages and disadvantages

    Gene × Gene interaction between MnSOD and GPX-1 and breast cancer risk: a nested case-control study

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    BACKGROUND: Germ-line mutations in genes such as BRCA1, BRCA2, and ATM can cause a substantial increase in risk of breast cancer. However, these mutations are rare in the general population, and account for little of the incidence of sporadic breast cancer in the general population. Therefore, research has been focused on examining associations between common polymorphisms and breast cancer risk. To date, few associations have been described. This has led to the hypothesis that breast cancer is a complex disease, whereby a constellation of very low penetrance alleles need to be carried to present a risk phenotype. Polymorphisms in the manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GPX-1) genes have been proposed as low penetrance alleles, and have not been clearly associated with breast cancer. We investigated whether variants at both polymorphisms, while not independently associated with breast cancer risk, could influence breast cancer risk when considered together. METHODS: A case-control study nested within the Nurses' Health Study was performed comparing 1262 women diagnosed with breast cancer to 1533 disease free women. The MnSOD (Val16Ala, rs1799725) and GPX-1 (Pro198Leu, rs1050450) were genotyped via TaqMan assay. Disease risk was evaluated using logistic regression. RESULTS: While neither allele alone shows any change in breast cancer risk, an increase in the risk of breast cancer (OR 1.87, 95% CI 1.09 – 3.19) is observed in individuals who carry both the Ala16Ala genotype of MnSOD and the Leu198Leu genotype of GPX-1. CONCLUSION: Polymorphisms in the GPX-1 and MnSOD genes are associated with an increased risk of breast cancer

    Study of deformation texture in an AZ31 magnesium alloy rolled at wide range of rolling speed and reductions

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    Having the lowest density among all structural metals, magnesium has opened new horizons for developing commercial alloys with successful use in a wide variety of applications [1-2]. However, the plasticity of Mg is restricted at low temperatures because: (a) only a small number of deformation mechanisms can be activated [3-4], and (b) a preferred crystallographic orientation (texture) develops in wrought alloys, especially in flat-rolled sheets [5-7]. Therefore, manufacturing processes such as rolling and stamping should be performed at elevated temperatures [1, 8]. These barriers to the manufacturing process increase the price of magnesium wrought alloy products and limits the use of Mg to castings [9-10]. As a result, many studies have been conducted to improve formability by investigating the effect of manufacturing process. Therefore the current sheet production techniques, based on DC casting and hot rolling, are basically slow because the demand is easily met [11]. Twin roll casting followed by hot rolling appears to be processing route which can fulfil high volumes and reduced costs. The present authors succeeded in single-pass large draught rolling of various magnesium alloy sheets at low temperature (<473K) by high speed rolling [12]. Based on the data available in those works [13- 17], the sheet obtained by high-speed rolling exhibited a fine-grained microstructure (mean grain size of 2-3 μm), with good mechanical properties. For these advantages, the high speed rolling is a promising process to produce high-quality rolled magnesium alloy sheets at a low cost. For these advantages, the HSR is a promising process to produce high-quality rolled magnesium alloy sheets at a low cost. The goal of this research is thus to investigate the mechanisms responsible for the much higher rollability and the grain refinement after HSR. To do that, in this study, different rolling speeds from 15 to 1000 m/min were employed to twin rolled cast AZ31B magnesium alloy and different reductions
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