4,287 research outputs found

    Optimization of the force characteristic of rotary motion type of electromagnetic actuator based on finite element analysis

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    The needs for non-invasive technique in breast cancer detection could enhance and preserve the future of medical field in Malaysia as well as countries around the world. Breast cancer has become the main concern nowadays not only for women but for man as well. In overall, the risk of women getting breast cancer is higher than man due to the denser tissue of breast in women compare to man. Beside the unawareness for the disease, the reason which contributes to this increasing number of breast cancer reported is also due to the limitations arising from modalities such as MRI, Mammography, ultrasound and other modalities. An alternative to current technologies should be improved for early detection and treatment which causes no physical harm to patients if possible. Thus, non-invasive and better technology in detecting breast cancer is very much needed in the current market. This paper will be discussing the insights of Magnetic Induction Tomography techniques in breast cancer detection

    On the quantum analogue of Galileo's leaning tower experiment

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    The quantum analogue of Galileo's leaning tower experiment is revisited using wave packets evolving under the gravitational potential. We first calculate the position detection probabilities for particles projected upwards against gravity around the classical turning point and also around the point of initial projection, which exhibit mass dependence at both these points. We then compute the mean arrival time of freely falling particles using the quantum probability current, which also turns out to be mass dependent. The mass dependence of both the position detection probabilities and the mean arrival time vanish in the limit of large mass. Thus, compatibility between the weak equivalence principle and quantum mechanics is recovered in the macroscopic limit of the latter.Comment: Latex, 12 pages, 1 figure, uses IOP style, clarifications and references adde

    Factor XIII A-Subunit V34L Variant Affects Thrombus Cross-Linking in a Murine Model of Thrombosis

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    Objective-Factor XIII (FXIII) cross-links fibrin upon activation by thrombin. Activation involves cleavage at residue 37 by thrombin, releasing an activation peptide. A common polymorphism (valine to leucine variant at residue 34, V34L), located in the activation peptide, has been associated with increased activation rates and paradoxically a protective effect in cardiovascular disease. There is, currently, no data available on the effects of V34L from in vivo models of thrombosis. We examined the effect of FXIII V34L on clot formation and cross-linking in vivo. Approach and Results-We generated a panel of full-length recombinant human FXIII-A2 variants with amino acid substitutions in the activation peptide to investigate the effect of these variants on activation rate, and we used wild-type, V34L, and alanine to glycine variant at residue 33 variants to study the effects of varying FXIII activation rate on thrombus formation in a murine model of FeCl3 injury. FXIII activation assay showed that residues 29, 30, 33, and 34 play a critical role in thrombin interaction. Full-length recombinant human FXIII-A2 V34L has significant effects on clot formation, structure, and lysis in vitro, using turbidity assay. This variant influenced fibrin cross-linking but not size of the thrombus in vivo. Conclusions-Mutations in the activation peptide of full-length recombinant FXIII regulate activation rates by thrombin, and V34L influences in vivo thrombus formation by increased cross-linking of the clot

    The effect of microwave roasting over the thermooxidative degradation of Perah seed oil during heating

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    The impact of microwave roasting on the thermooxidative degradation of perah seed oil (PSO) was evaluated during heating at a frying temperature (170℃). The roasting resulted significantly lower increment of the values of oxidative indices such as free acidity, peroxide value, p-anisidine, total oxidation (TOTOX), specific extinctions and thiobarbituric acid in oils during heating. The colour L* (lightness. Value dropped gradually as the heating time increased up to 12 h, whereas a*(redness. and b* (yellowness). Tended to increase. The viscosity and total polar compound in roasted PSO was lower as compared to that in unroasted one at each heating times. The tocol retention was also high in roasted samples throughout the heating period. The relative contents of polyunsaturated fatty acids (PUFAs. were decreased to 94.42% and saturated fatty acids (SFAs. were increased to 110.20% in unroasted sample, after 12 h of heating. On the other hand, in 3 min roasted samples, the relative contents of PUFAs were decreased to 98.08% and of SFAs were increased to 103.41% after 12 h of heating. Outcome from analyses showed that microwave roasting reduced the oxidative deteriorations of PSO during heating

    Dual-stage gain-clamped erbium-doped fiber amplifier with fiber Bragg grating

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    We demonstrate a dual-stage gain-clamped erbiumdoped fiber amplifier. The first-stage amplifier consists of a short length of erbium-doped fiber to produce low noise figures. The second-stage is constructed from a counter-propagating ringlaser, in which the signals and the lasing wavelength propagate in the opposite direction. The lasing wavelength is selected via a reflective-type of fiber Bragg grating. The gain-clamping mechanism can be adjusted by either changing the fiber Bragg grating reflectivity or center wavelength. The noise figure penalty is about 1.5 dB for the gain-clamping value from 11 dB to 20.5 dB. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA

    Noncommutative Conformally Coupled Scalar Field Cosmology and its Commutative Counterpart

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    We study the implications of a noncommutative geometry of the minisuperspace variables for the FRW universe with a conformally coupled scalar field. The investigation is carried out by means of a comparative study of the universe evolution in four different scenarios: classical commutative, classical noncommutative, quantum commutative, and quantum noncommutative, the last two employing the Bohmian formalism of quantum trajectories. The role of noncommutativity is discussed by drawing a parallel between its realizations in two possible frameworks for physical interpretation: the NC-frame, where it is manifest in the universe degrees of freedom, and in the C-frame, where it is manifest through theta-dependent terms in the Hamiltonian. As a result of our comparative analysis, we find that noncommutative geometry can remove singularities in the classical context for sufficiently large values of theta. Moreover, under special conditions, the classical noncommutative model can admit bouncing solutions characteristic of the commutative quantum FRW universe. In the quantum context, we find non-singular universe solutions containing bounces or being periodic in the quantum commutative model. When noncommutativity effects are turned on in the quantum scenario, they can introduce significant modifications that change the singular behavior of the universe solutions or that render them dynamical whenever they are static in the commutative case. The effects of noncommutativity are completely specified only when one of the frames for its realization is adopted as the physical one. Non-singular solutions in the NC-frame can be mapped into singular ones in the C-frame.Comment: explanations added, references include

    Identification of bioactive compounds with GC Q-TOF MS in the extracts from Clinacanthus nutans using subcritical carbon dioxide extraction

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    Subcritical carbon dioxide Soxhlet extraction of biologically active compounds from Clincanthus nutans was investigated by full factorial design to identify and optimize the factors (particle size and co-solvent) affecting extract yield, antioxidant activity, total phenolic content, total flavonoid content, and α-glucosidase inhibitory activity. An average of 3.103% yield, 98.90% antioxidant activity, 49.40 mg/g (GAE) TPC, 43.76 mg/g (RE), and 88.58% AGI activity can be achieved using the optimum levels of independent variables. The GC-Q-TOF MS identification of optimized extract shown that different classes of phytoconstituents were successfully separated by CO2-Soxhlet to produce potential antioxidant and α-glucosidase inhibitory activity

    Effect of accelerated storage on chemical compositions of mango seed fat and palm oil mid-fraction blends as cocoa butter replacers

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    In this study, mango seed fat (MSF) and its recommended blends were stored under accelerated condition. During the accelerated storage, the changes of fatty acids, total phenolic, tocopherol, and phytosterol contents, iodine, free fatty acid (FFA), and peroxide values were examined every six days. Results upon storage, palmitic and stearic acids increased from 18.0 to 22.5% and from 33.3 to 36.7%, while oleic and linoleic acids decreased from 40.5 to 34.3% and from 5.4 to 2.1% in blend containing 85 g MSF/100 g fat. The iodine values of MSF and its recommended blends decreased (48.2 ± 1.2 to 32.0 ± 0.8 g iodine/100 g fat), while the peroxide (1.1e4.2 ± 0.0 milliequivalent O2/kg fat) and FFA (1.8-3.9 ± 0.0 g/100 g of fat) values increased after accelerated storage. The results obtained from this study provide an indication about the storage stability of MSF and its blends as cocoa butter replacers to food industry, in particular chocolate industry

    Removal of hexavalent chromium of contaminated soil by coupling electrokinetic remediation and permeable reactive biobarriers

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    PURPOSE: In this study, a novel and ecological alternative have been developed to treat soils contaminated with hexavalent chromium coupling two well-known systems: electrokinetic remediation and permeable reactive biobarriers. The electric field promotes the electromigration of the hexavalent chromium oxyanions towards the anode. The biobarriers were placed before the anode electrode, in order to promote the reduction and retention of the chromium migrating in its direction. Thus, this technology provided a global treatment to soil removal without subsequent treatments of the contaminated effluents. METHODS: The electrokinetic system was coupled with two different permeable reactive biobarriers composed by Arthrobacter viscosus bacteria, supported either in activated carbon or zeolite. An electric field of 10 V was applied and two different treatment times of 9 and 18 days were tested. RESULTS: Removal values of 60% and 79% were obtained when electrokinetic treatment was coupled with zeolite and activated carbon biobarriers, respectively, for a test period of 18 day. The reduction of hexavalent chromium to trivalent chromium was around 45% for both systems. CONCLUSIONS: In this work, two types of biobarriers were efficiently coupled to electrokinetic treatment to decontaminate soil with Cr(VI). Furthermore, the viability of the new coupling technology developed (electrokinetic + biobarriers) to treat low-permeability polluted soils was demonstrated.This work was supported by the Spanish Ministry of Science and Innovation (CTQ2008-03059/PPQ), Xunta de Galicia (08MDS034314PR). The authors are grateful to the Spanish Ministry of Science and Innovation for providing financial support for Marta Pazos under the Ramon y Cajal program and the Fundacao para a Ciencia e Tecnologia, Ministerio da Ciencia e Tecnologia, Portugal through the PhD grant of Bruna Fonseca (SFRH/BD/27780/2006)
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