780 research outputs found
Molecular Dynamics Simulation of the ENTH Domain on Lipid Bilayer
This research study compares the effect of polypropylene and wool fibers on the mechanical properties of natural polymer based stabilized soils. Biocomposites are becoming increasingly prevalent and this growth is expected to continue within a number of sectors including building materials. The aim of this study was to investigate the influence of different fiber reinforced natural polymer stabilized soils with regards to mechanical properties and fiber adhesion characteristics. The polymer includes alginate, which is used in a wide range of applications but has not been commonly used within engineering and construction applications. In recent years, natural fibers have started to be used as an ecological friendly alternative for soil reinforcement within a variety of construction applications. Test results in this study have compared the effects of adding natural and synthetic fibers to clay soils and discussed the importance of an optimum soil specification. A correlation between the micro structural analysis using scanning electron microscope (SEM), fiber typology, fiber–matrix bonds and the mechanical properties of the stabilized soils is also discussed
Tight Competitive Analyses of Online Car-Sharing Problems
The car-sharing problem, proposed by Luo, Erlebach and Xu in 2018, mainly
focuses on an online model in which there are two locations: 0 and 1, and
total cars. Each request which specifies its pick-up time and pick-up location
(among 0 and 1, and the other is the drop-off location) is released in each
stage a fixed amount of time before its specified start (i.e. pick-up) time.
The time between the booking (i.e. released) time and the start time is enough
to move empty cars between 0 and 1 for relocation if they are not used in that
stage. The model, called S2L-F, assumes that requests in each stage arrive
sequentially regardless of the same booking time and the decision (accept or
reject) must be made immediately. The goal is to accept as many requests as
possible. In spite of only two locations, the analysis does not seem easy and
the (tight) competitive ratio (CR) is only known to be 2.0 for and 1.5
for a restricted value of , i.e., a multiple of three. In this paper, we
remove all the holes of unknown CR's; namely we prove that the CR is
for all . Furthermore, if the
algorithm can delay its decision until all requests have come in each stage,
the CR is improved to roughly 4/3. We can take this advantage even further,
precisely we can achieve a CR of if the number of requests in
each stage is at most , , where we do not have to know the
value of in advance. Finally we demonstrate that randomization also helps
to get (slightly) better CR's
Effects of Propane/Nitrogen Mixtures on Thermal Chemical Vapor Deposition Rates and Microstructures of Carbon Films
When propane/nitrogen (C3H8/N2) mixtures are used to deposit carbon films by thermal chemical vapor deposition (CVD), effects of C3H8/(C3H8+N2) ratios on the deposition rate and microstructures of carbon films are investigated. Experimental results show that as the C3H8/(C3H8+N2) ratio increases from 20 to 100%, the deposition rate increases from 23.7 to 127 nm/min. Alternatively, if the residence time, deposition temperature, and working pressure raise, the deposition rate of carbon films also increases. The kinetics of this thermal CVD process is discussed. The activation energy obtained in this work is 234 kJ/mole. Furthermore, this CVD reaction is controlled by a process of about first order, which is resulted from the adsorption of main product gases, acetylene (C2H2) and ethylene (C2H4), on the silica glass plate substrate. Few nitrogen and hydrogen atoms are incorporated into carbon films. The crystallinity, ordering degree, and nano-crystallite size of carbon films decrease with increasing the C3H8/(C3H8+N2) ratio. Meanwhile, as the C3H8/(C3H8+N2) ratio increases from 20 to 100%, the sp2/(sp2+sp3) ratio of carbon films decreases from 92 to 61%. Finally, the results of thermal CVD carbon deposition using C3H8/N2 mixtures are compared with those using methane/nitrogen (CH4/N2), C2H2/N2, and C2H4/N2 mixtures
Impact of body-mass factors on setup displacement in patients with head and neck cancer treated with radiotherapy using daily on-line image guidance
BACKGROUND: To determine the impact of body-mass factors (BMF) before radiotherapy and changes during radiotherapy on the magnitude of setup displacement in patients with head and neck cancer (HNC). METHODS: The clinical data of 30 patients with HNC was analyzed using the alignment data from daily on-line on-board imaging from image-guided radiotherapy. BMFs included body weight, body height, and the circumference and bilateral thickness of the neck. Changes in the BMFs during treatment were retrieved from cone beam computed tomography at the 10th and 20th fractions. Setup errors for each patient were assessed by systematic error (SE) and random error (RE) through the superior-inferior (SI), anterior-posterior (AP), and medial-lateral (ML) directions, and couch rotation (CR). Using the median values of the BMFs as a cutoff, the impact of the factors on the magnitude of displacement was assessed by the Mann–Whitney U test. RESULTS: A higher body weight before radiotherapy correlated with a greater AP-SE (p = 0.045), SI-RE (p = 0.023), and CR-SE (p = 0.033). A longer body height was associated with a greater SI-RE (p = 0.002). A performance status score of 1 or 2 was related to a greater AP-SE (p = 0.043), AP-RE (p = 0.015), and SI-RE (p = 0.043). Among the ratios of the BMFs during radiotherapy, the values at the level of mastoid tip at the 20(th) fraction were associated with greater setup errors. CONCLUSIONS: To reduce setup errors in patients with HNC receiving RT, the use of on-line image-guided radiotherapy is recommended for patients with a large body weight or height, and a performance status score of 1–2. In addition, adaptive planning should be considered for those who have a large reduction ratio in the circumference (<1) and thickness (<0.94) over the level of the mastoid tip during the 20(th) fraction of treatment
Development and evaluation of a loop-mediated isothermal amplification method for rapid detection and differentiation of two genotypes of porcine circovirus type 2
BackgroundPorcine circovirus type 2 (PCV2) is one of the major swine viral diseases and has caused significant economic loss to pig producers. PCV2 has been divided into two major genotypes: PCV2a, PCV2b. A loop-mediated isothermal amplification (LAMP) method was developed for the detection and differentiation of PCV2a and PCV2b in clinical samples.MethodsLAMP-specific primer sets were designed based on six PCV2a and six PCV2b reference isolates. To determine the analytical specificity of LAMP, DNA samples extracted from 36 porcine virus isolates were tested by LAMP, including eight PCV2a, 11 PCV2b, four PCV type 1, two porcine parvovirus, three pseudorabies virus, and eight porcine reproductive and respiratory virus. To evaluate the analytical sensitivity of the assay, 10-fold serial dilutions of PCV2a and PCV2b recombinant plasmids were performed to prepare the dilutions at concentration from 106 to 1 copy(ies)/μL, and each dilution was tested by both LAMP and nested polymerase chain reaction (nested PCR). A total of 168 clinical samples were analyzed by both LAMP and nested PCR, and the relative sensitivity and specificity of LAMP compared to nested PCR were calculated.ResultsUsing different primer sets of LAMP, LAMP could be completed within 50 minutes. This method was found to be highly analytically specific for PCV2a and PCV2b; only the target gene was detected without cross-reaction. The analytical sensitivity of LAMP for PCV2a and PCV2b were 10 copies/μL, demonstrating analytical sensitivity comparable to that obtained using nested PCR. In addition, the sensitivity and specificity of LAMP relative to those of nested PCR were 97.7% and 100.0%, respectively. The percentage of observed agreement was 98.2%, and the κ statistic was 0.949.ConclusionLAMP is a rapid, specific, and sensitive diagnostic method for the detection and differentiation of PCV2a and PCV2b in clinical samples
Thermal Analysis and Characterization of Polystyrene Initiated by Benzoyl Peroxide
PresentationBased on the complexity of the polystyrene polymerization mechanism initiated by benzoyl peroxide (BPO), the thermal risk of the reaction process was estimated using thermal analysis and characterization. The polymerization process was thermally analysed using an adiabatic rate calorimeter and differential scanning calorimeter. The results demonstrated that the onset reaction temperature, adiabatic temperature rise, and maximum temperature of the synthesis reaction of BPO-initiated polymerization were lower than those of thermos initiated polymerization. Moreover, nuclear magnetic resonance imaging, gel permeation chromatography, and Fourier transform infrared spectrometry were used to characterize the polymerization products obtained under the two initiation conditions. The polystyrene obtained using the two initiation methods had the same hydrogen structure; however, their molecular weight and distribution uniformity differed considerably, and the BPO-initiated process was discovered to include the effects of the thermos initiated process. Moreover, the free radicals produced by BPO decomposition participated in the chain reaction of polystyrene polymerization, accelerated instantaneous grain growth, and promoted the formation of short- chain polystyrene. In summary, the BPO-initiated polymerization process exhibited the desired thermal safety characteristics and has potential for practical use
Lasing on nonlinear localized waves in curved geometry
The use of geometrical constraints opens many new perspectives in photonics
and in fundamental studies of nonlinear waves. By implementing surface
structures in vertical cavity surface emitting lasers as manifolds for curved
space, we experimentally study the impacts of geometrical constraints on
nonlinear wave localization. We observe localized waves pinned to the maximal
curvature in an elliptical-ring, and confirm the reduction in the localization
length of waves by measuring near and far field patterns, as well as the
corresponding dispersion relation. Theoretically, analyses based on a
dissipative model with a parabola curve give good agreement remarkably to
experimental measurement on the transition from delocalized to localized waves.
The introduction of curved geometry allows to control and design lasing modes
in the nonlinear regime.Comment: 6 pages, 6 figure
Effects of steel slag application on greenhouse gas emissions and crop yield over multiple growing seasons in a subtropical paddy field in China
Asia is responsible for over 90% of the world's rice production and hence plays a key role in safeguarding food security. With China being one of the major global producers and consumers of rice, achieving a sustainable balance in maximizing crop productivity and minimizing greenhouse gas emissions from paddy fields in this country becomes increasingly important. This study examined the effects of applying steel slag, a residual product derived from the steel industry, on crop yield and CH4 and N2O emissions over multiple growing seasons in a Chinese subtropical paddy field. Average CH4 emission was considerably higher during the periods of rice crop growth compared to that during the periods of fallowing and vegetable crop growth, regardless of the amount of steel slag applied. When compared to the controls, significantly lower mean emissions of CH4 (1.03 vs. 2.34 mg m−2 h−1) and N2O (0.41 vs. 32.43 μg m−2 h−1) were obtained in plots with slag addition at a rate of 8 Mg ha−1 over the study period. The application of slag at 8 Mg ha−1 increased crop yields by 4.2 and 9.1% for early and late rice crops, respectively, probably due to the higher availability of inorganic nutrients such as silicates and calcium from the slag. Slag addition had no significant effect on the concentrations of heavy metals in either the soil or the rice grains, although a slight increase in the levels of manganese and cobalt in the soil and a decrease in the levels of manganese and zinc in the rice grains were observed. Our results demonstrate the potential of steel slag as a soil amendment in enhancing crop yield and reducing greenhouse gas emissions in subtropical paddy fields in China, while posing no adverse short-term impacts on the concentrations of heavy metals in the soil or the rice grains. However, long-term implications of this management practice and the cost/benefit remain unknown, so further studies to assess the suitability at large scale are warranted
Protection Effect of Zhen-Wu-Tang on Adriamycin-Induced Nephrotic Syndrome via Inhibiting Oxidative Lesions and Inflammation Damage
Zhen-wu-tang (ZWT), a well-known formula in China, is widely used to treat chronic kidney diseases. However, very little information on ZWT’s mechanism of action is currently available. In this study, we investigated the possible protective role and underlying mechanism of ZWT on nephrotic syndrome (NS) induced by Adriamycin (intravenous injection, 6.0 mg/kg) in rats using biochemical and histopathological approaches. ZWT decreased urine protein excretion and the serum levels of total cholesterol, triglycerides, blood urea nitrogen, and creatinine significantly in diseased rats. A decrease in plasma levels of total protein and albumin was also recorded in nephropathic rats. Pathological results show an improved pathological state and recovering glomerular structure in ZWT treatment groups. ZWT decreased renal IL-8 level but increased renal IL-4 level. In addition, rats subjected to ZWT exhibited less IgG deposition in glomerulus compared with model group. RT-PCR results showed that ZWT decreased the mRNA expression of NF-κB p65 and increased the mRNA expression of IκB. Furthermore, ZWT reduced the level of MDA and increased SOD activity. These results demonstrated that ZWT ameliorated Adriamycin-induced NS in rats possibly by inhibiting Adriamycin-induced inflammation damage, enhancing body’s antioxidant capacity, thereby protecting glomerulus from injury
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