8,985 research outputs found

    Influence of amendments on soil structure and soil loss under simulated rainfall China’s loess plateau

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    Macromolecule polymers are significant types of chemical amendments because of their special structure, useful functions and low cost. Macromolecule polymers as soil amendment provide new territory for studying China’s agricultural practices and for soil and water conservation, because polymers have the ability to improve soil structure, increase rainfall penetration and control slope runoff. Through indoor laboratory experiments and outdoor artificial rainfall simulations, this study applied different consistencies of three amendments; polypropylene acid (PPA), polythene alcoholic (PTA) and urea-formaldehyde poly-condensate (UR) to China’s Loess and determined their effects on soil physical properties and on runoff-sediment yield. The results indicate that as a result of applying the amendments, (1) the water-stable soil aggregates content increases by 17.3%, the soil permeability increases by 41.8%, the soil density decreases by 11.2% and the soil water content increases by 28.0% compared to the control; (2) three amendment applied on sloping land can delay runoff and decrease runoff velocity; decrease erosive forces of raindrop impact and flowing water, reduce surface crusting and improve water infiltration, delay runoff engenderation and decrease runnoff velocity and soil erosion yield. Finally, this study also ascertained optimal application quantities and the most effective sort in three amendments, which PPA is most effective at lowering surface runoff, reducing soil loss and increasing soil penetration. These three amendments have broad potential for soil and water conservation; however, the duration of their effect and the optimal application quantities need to be researched further.Key words: Amendment, Runoff-Sediment Yield, Soil Physical Properties, Soil erosio

    Diffusion tensor imaging of renal ischemia/reperfusion injury

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    Session 67: Functional MRI of the Abdomen - Oral presentationRenal ischemia/reperfusion injury (IRI) is a major cause of acute renal failure in native and in transplanted kidneys. IRI in kidney associated with transplantation may also influence early graft function and late changes. Recently, anisotropy measurement with diffusion tensor imaging (DTI) has been found to provide additional information about functional and structural status of kidney. In this study, we aim at characterizing diffusion properties of kidney with mean diffusivity (MD) and fractional anisotropy (FA) in an experimental rat model of renal IRI. The experimental results demonstrated that DTI is useful in identifying renal IRI by characterizing the changes in MD and FA.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 66

    Tourism forecasting : to combine or not to combine?

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    Author name used in this publication: Kevin K. F. Wong2006-2007 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    An empirical study of forecast combination in tourism

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    Author name used in this publication: Kevin F. Wong2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Anti-tumorigenic and Pro-apoptotic effects of CKBM on gastric cancer growth in nude mice

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    Natural botanical products can be integrated with western medicine to optimize the treatment outcome, increase immune function and minimize the side effects from western drug treatment. CKBM is a combination of herbs and yeasts formulated based on traditional Chinese medicinal principles. Previous study has demonstrated that CKBM is capable of improving immune responsiveness through the induction of cytokine mediators, such as TNF-α and IL-6. In this study, we aimed to investigate the effect of this immunomodulatory drug on gastric cancer growth using a human xenograft model. Gastric cancer tissues were implanted subcutaneously into athymic nude mice followed by a 14-day or 28-day of CKBM treatment. Results showed that higher doses of CKBM (0.4 or 0.8 ml/mouse/day) produced a dose-dependent inhibitory effect on gastric tumor growth after 28-day drug treatment. This was associated with a decrease of cellular proliferation by 30% with concomitant increase in apoptosis by 97% in gastric tumor cells when compared with the control group. In contrast, CKBM showed no effect on angiogenesis in gastric tumors. This study demonstrates the anti-tumorigenic action of CKBM on gastric cancer probably via inhibition of cell proliferation and induction of apoptosis, and provides future potential targets of this drug candidate on cancer therapy.published_or_final_versio

    Octreotide Therapy in Asparaginase-Associated Pancreatitis in Childhood Acute Lymphoblastic Leukemia

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    [[abstract]]Little is known about octreotide therapy in asparaginase-associated pancreatitis (AAP) in children. Of the 59 children with acute lymphoblastic leukemia (ALL) receiving E. Coli L-asparaginase, 5 patients (8.5%) developed AAP. Octreotide was administered to four patients. Clinical and laboratory improvement were evident after octreotide therapy. There were no deaths and no severe adverse side effects were noted. No pseudocysts were detected; however, two of the four patients developed diabetes. One child without octreotide treatment developed chronic pancreatitis and pseudocyst. We conclude that octreotide therapy appears to be safe and potentially beneficial in the management of AAP in children

    Substrate co-doping modulates electronic metal-support interactions and significantly enhances single-atom catalysis

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    Transitional metal nanoparticles or atoms deposited on appropriate substrates can lead to highly economical, efficient, and selective catalysis. One of the greatest challenges is to control the electronic metal–support interactions (EMSI) between the supported metal atoms and the substrate so as to optimize their catalytic performance. Here, from first-principles calculations, we show that an otherwise inactive Pd single adatom on TiO2(110) can be tuned into a highly effective catalyst, e.g. for O2 adsorption and CO oxidation, by purposefully selected metal–nonmetal co-dopant pairs in the substrate. Such an effect is proved here to result unambiguously from a significantly enhanced EMSI. A nearly linear correlation is noted between the strength of the EMSI and the activation of the adsorbed O2 molecule, as well as the energy barrier for CO oxidation. Particularly, the enhanced EMSI shifts the frontier orbital of the deposited Pd atom upward and largely enhances the hybridization and charge transfer between the O2 molecule and the Pd atom. Upon co-doping, the activation barrier for CO oxidation on the Pd monomer is also reduced to a level comparable to that on the Pd dimer which was experimentally reported to be highly efficient for CO oxidation. The present findings provide new insights into the understanding of the EMSI in heterogeneous catalysis and can open new avenues to design and fabricate cost-effective single-atom-sized and/or nanometer-sized catalysts

    Do thermal effects cause the propulsion of bulk graphene material?

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    In a recent article, Zhang et al.1 observed the direct propulsion of a bulk graphene sponge when exposed to laser light. They attributed this to the momentum of the light-induced ejected electrons. However, the force provided by the ejected electrons is about 2.7 × 10−11 N (supposing that the average current and the kinetic energy of the ejected electrons are 9 × 10−7 A and 70 eV, respectively), which is far smaller than the gravitational force of a 0.86 mg graphene sponge. From our knowledge of rarefied gas dynamics, the horizontal, vertical and rotational motion of the laser-illuminated graphene sponge could be due to the radiometric force

    Resampling methods to reduce the selection bias in genetic effect estimation in genome-wide scans

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    Using the simulated data of Problem 2 for Genetic Analysis Workshop 14 (GAW14), we investigated the ability of three bootstrap-based resampling estimators (a shrinkage, an out-of-sample, and a weighted estimator) to reduce the selection bias for genetic effect estimation in genome-wide linkage scans. For the given marker density in the preliminary genome scans (7 cM for microsatellite and 3 cM for SNP), we found that the two sets of markers produce comparable results in terms of power to detect linkage, localization accuracy, and magnitude of test statistic at the peak location. At the locations detected in the scan, application of the three bootstrap-based estimators substantially reduced the upward selection bias in genetic effect estimation for both true and false positives. The relative effectiveness of the estimators depended on the true genetic effect size and the inherent power to detect it. The shrinkage estimator is recommended when the power to detect the disease locus is low. Otherwise, the weighted estimator is recommended

    A novel 16-channel wireless system for electroencephalography measurements with dry spring-loaded sensors

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    Understanding brain function using electroencephalography (EEG) is an important issue for cerebral nervous system diseases, especially for epilepsy and Alzheimer's disease. Many EEG measurement systems are used reliably to study these diseases, but their bulky size and the use of wet sensors make them uncomfortable and inconvenient for users. To overcome the limitations of conventional EEG measurement systems, a wireless and wearable multichannel EEG measurement system is proposed in this paper. This system includes a wireless data acquisition device, dry spring-loaded sensors, and a sizeadjustable soft cap. We compared the performance of the proposed system using dry versus conventional wet sensors. A significant positive correlation between readings from wet and dry sensors was achieved, thus demonstrating the performance of the system. Moreover, four different features of EEG signals (i.e., normal, eye-blinking, closed-eyes, and teeth-clenching signals) were measured by 16 dry sensors to ensure that they could be detected in real-life cognitive neuroscience applications. Thus, we have shown that it is possible to reliably measure EEG signals using the proposed system. This paper presents novel insights into the field of cognitive neuroscience, showing the possibility of studying brain function under real-life conditions. © 2014 IEEE
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