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121.
Polyacrylonitrile nanofibers were produced using the electrospinning method and dyed with a basic dye alongside regular polyacrylonitrile fibers. In order to investigate the effect of high surface area to volume ratio of nanofibers on their adsorption behavior in comparison with regular fibers, the dyeing conditions for both types of fibers were kept just the same. Physiochemical parameters of dyeing such as adsorption isotherm, standard affinity, enthalpy change, rate of dyeing constant, diffusion coefficient, and activation energy of diffusion were investigated for both types of fibers. The results showed that the adsorption process can be well described with the Langmuir adsorption isotherm for both types of fibers whereas the standard affinity of dye to nanofibers was higher than regular fibers and the higher negative values of enthalpy changes were obtained for regular fibers. The nanofibers rate of dyeing was faster than regular fibers with higher amounts of diffusion coefficients and lower amounts of activation energy of diffusion. This study also revealed that in spite of the approximately same amount of dye exhaustion for both types of fibers, the color strength of regular fibers was noticeably higher than nanofibers.  相似文献   
122.
Estimating soil organic carbon from soil reflectance: a review   总被引:1,自引:0,他引:1  
Soil organic carbon (SOC) concentration is a useful soil property with which to guide agricultural applications of chemical inputs. To enable this, simple, accurate, rapid and inexpensive methods are needed to produce maps of surface SOC concentrations. Researchers have investigated estimates of soil surface properties from remotely sensed information as a means of rapidly quantifying and monitoring some surface soil properties, such as SOC. The objective of this paper is to review the potential and limitations of remotely sensed data for mapping and evaluating SOC. Several statistical methods including simple regression models, the ‘soil line’ approach, principal component analysis and geostatistics have been applied to data to investigate the accuracy of such estimates. A review of the literature shows that predictive equations are not universal and require new regression models for every scene. An important benefit of remotely sensed data is to suggest a sampling strategy that can lead to improved representation of spatial heterogeneity in SOC.  相似文献   
123.
Minimum inhibitory concentrations (MICs) of 20 antimicrobial agents for 41 isolates of Burkholderia mallei from natural outbreaks of equine glanders were determined by agar dilution. All isolates were intrinsically resistant to ampicillin (MIC90 ≥128). Resistance to other antimicrobials was as follows: 95.1% to amoxicillin and cephradine, 85.4% to cefuroxime and norfloxacin, 68.3% to ceftizoxime and ceftriaxone, 61.1% to ceftiofur, 58.5% to oxytetracycline, 41.5% to ciprofloxacin, 58.5% to roxithromycin, 17.1% cefotaxime, and 12.2% clarithromycin. Overall resistance patterns revealed that 17% of isolates were simultaneously resistant to amoxicillin, cephradine, cefuroxime, ceftizoxime, ceftriaxone and norfloxacin. None of the isolates were resistant to amoxicillin-clavulanic acid, doxycycline, chloramphenicol, gentamicin or trimethoprim-sulphadiazine. Mode MICs for these antimicrobials were 2, 1, 8, 4 and 1 μg/ml, respectively. A majority of the isolates (∼ 94%) were susceptible to both enrofloxacin and ofloxacin. These data provide an updated perspective on susceptibility profiles of current strains of B. mallei in an endemic area.  相似文献   
124.

Background

Attempts for early detection of gastric cancer have recently focused on host''s genetic susceptibility factors and gene-environment interactions. We have, herein, studied the association of MTHFR C677T single nucleotide polymorphism (SNP) and its interaction with Helicobacter pylori infection, smoking, age and gender on the risk of gastric cancer among an Iranian population.

Methods

Gastric cancer patients (n = 450) and cancer-free controls (n = 780) were studied for serum H. pylori-specific IgG antibodies by ELISA and MTHFR C677T polymorphism (SNP) by PCR-RFLP. Demographic and life style data were collected through patient interviews. Unconditional logistic regression model estimated odds ratio (OR) and the corresponding 95% confidence intervals (CI).

Results

The interactions of MTHFR genotype with H. pylori infection (P = 0.03), age (P = 0.049) and gender (P = 0.007) were statistically significant. Accordingly, MTHFR C677T carriers who were also positive for H. pylori infection exhibited 80% (OR = 1.8, 95% CI = 1.0-2.9) significant excess risk of non-cardia gastric cancer. Furthermore, subjects over the age of 50 or female subjects carrying MTHFR C677T SNP showed 40 (OR = 1.4, 95% CI = 1.0-2.0) and 100 (OR = 2.0, 95% CI = 1.2-3.2) percent increased risk of gastric cancer, respectively.

Conclusion

MTHFR C677T SNP seems to increase the risk of gastric cancer and the effect is significantly inflated by interactions with H. pylori infection, age and gender. Key Words: Helicobacter pylori, Smoking, Gender identity, Age group, Methylenetetrahydrofolate reductase  相似文献   
125.
Milk is the most nourishing natural biofluid and almost an ideal functional food for humans of all ages. The objective of this review article is to delineate global nutritional and health implications of main live-stock dairy products for optimum postmodern life quality. Milk bioactives contribute considerably to meeting nutrient requirements while offering potentials to reduce risks of cancers, traumas and metabolic disorders. Milk functions beyond its nutritive worth. Cow milk intake by lactating mothers enriches breast milk ??-lactoglobulin and ovalbumin. Milk intake leads to more standard body frame structure and bone health. Milk immunoglobulins act against Enterotoxigenic Escherichia coli. Casomorphins, immunostimulating peptides, and ACE-inhibitory peptides modulate the gut nutrient assimilation. Whey proteins are insulinotropic and medium chain fatty acids improve insulin action. Peptides along with calcium may reduce blood pressure and cholesterol. Milk improves folate availability, and reduces homocysteinemia and heart infarcts. Ewe milk is richer than cow milk in riboflavin, thiamine, niacin, pantothenic acid, vitamin B6, vitamin B12 and biotin. Goat milk has less ??-s-1-casein, ??-carotene, agglutinin; and is lower in citric acid, Na, Fe, S, Zn, Mo, ribonuclease, alkaline phosphatase, lipase, xanthine oxidase, N-acetylneuraminic acid, orotic acid, pyridoxine, folate, vitamin B12, and vitamin C than cow milk. Goat milk is richer in Ca, K, Mg, P, Cl, Mn, vitamins A and D, nicotinic acid, choline, inositol, medium-chain FA, small diameter fat globules than cow milk. Goat milk is a suitable substitute in allergies, and with low orotic acid might prevent fatty liver. Lysozyme-rich milk has been produced with transgenic dairy goats to prevent intestinal disorders in infants. Donkey and horse milks are considered optimal substitutes for human and cow milk in minimizing allergies and hyperlipidemia related complexities. Effective education and data dissemination are the ongoing obligations for unbiased milk science to be adequately perceived and applied by postmodern human populations.  相似文献   
126.
We determined the effects of the penetration depth and spline material and composite material type as well as joining method on bending moment resistance under diagonal compression and tension in common wood panel structures. Composite materials were laminated medium density fiberboard (MDF) and particle board. Joining methods were buttand miter types. Spline materials were high density fiber board (HDF).The penetration depths of plywood, wood (Carpinus betolus) and splinewere 8, 11 and 14 mm. The results showed that in both diagonal compression and tension, MDF joints are stronger than particle board joints,and the bending moment resistance under compression is higher compared with that in tension. The highest bending moment resistance under tension was shown in MDF, butt joined using plywood spline with 8 mm penetration depth, whereas under compression bending moment resistance was seen in MDF, miter joined with the HDF spline of 14 mm penetration depth.  相似文献   
127.
An 8‐week feeding trial was run to investigate the replacement of fishmeal with corn protein concentrate (CPC; Empyreal®) in rainbow trou (100.5 ± 2.3 g) diet. Fishmeal was increasingly replaced with 0 (Control), 30 (CPC3), 60 (CPC6), 90 (CPC9) and 120 (CPC12) g/kg CPC. The results showed that the substitution of fishmeal with CPC up to 90 g/kg did not cause significant differences in the growth indices as compared to the control group, while further replacement resulted in the reduction of the growth performance. The fillet crude protein showed no significant difference between the control diet and diets containing up to 90 g/kg CPC (p > .05). Serum biochemical parameters such as albumin and glucose did not change notably, while the highest levels of alanine aminotransferase and lactate dehydrogenase were seen in the CPC12 group (p < .05). Also, serum lysozyme activity was increased with the elevation of dietary CPC up to 90 g/kg (p < .05). The redness and yellowness of the fillet were markedly elevated with the dietary incorporation of CPC (p < .05). Taken together, the optimum range of fishmeal substitution with CPC was 81.0–82.2 g/kg CPC in rainbow diet based on the broken‐line regression analysis.  相似文献   
128.
Increasing release of organic pollutants to the environment has caused one of the largest world crises for water resources. Volatile organic compounds are toxic monoaromatic pollutants of soil and water. In this research, natural zeolite nanoparticles were produced mechanically by means of a milling technique, modified using two cationic surfactants of hexadecyltrimethylammonium chloride and n-cetyl pyridinium bromide and formed as granules using a novel technique already developed by our group. The granulated adsorbents were used to uptake benzene, toluene, ethylbenzene, and xylenes (BTEX) from contaminated water. Two intra-particle diffusion models (i.e., Weber and Morris and Vermeulen models) and three surface reaction models (i.e., pseudo-first order, pseudo-second order, and Elovich) were applied to evaluate the kinetics of adsorption and the best fitted model was chosen. Results of the adsorption kinetic evaluations were shown that uptake of granulated nanozeolites are higher than natural zeolites (in the order of four). Kinetic results revealed that the adsorption follows a pseudo-second order indicating existence of chemisorption in the studied conditions. It was noticed that the intra-particle diffusion is prevailing in the first stage of adsorption for a relatively short time (i.e., first 25 min).  相似文献   
129.
The aim of the present study was to evaluate the effect of cultivation of some agronomic plant species on inorganic soil‐P fractions in different sampling zones. The experiment was conducted as a completely randomized design as factorial in three replicates. The factors were plant species (10 different species and control) and soil‐sampling zone (soil adhering to root mat, rhizosphere soil, and nonrhizospheric soil). The thin‐slicing technique was modified and used to sample rhizosphere soil. The percentages of P fractions in the planted and control soils were near 64% apatite (apatite‐P), 24% octa‐Ca‐phosphates (OCP‐P), 7% Fe‐phosphates (Fe‐P), 4% di‐Ca‐phosphates (DCP‐P), 1% Al‐phosphates (Al‐P), and 0% occluded‐P (O‐P). All of the studied plant species decreased significantly all of the inorganic P fractions in soil adhering to root mat and in rhizosphere soil compared to those in nonrhizosphere soil. However, these decreases were not equal for each fraction and the percentage of apatite‐P increased in rhizosphere soil of the plant species. The means of total P, soluble P, DCP‐P, OCP‐P, Al‐P, and Fe‐P were lower in soil adhering to root mat compared to those in rhizosphere soil. However, this difference was only significant for OCP‐P. In contrast, the mean of apatite‐P in soil adhering to root mat was significantly higher than that in rhizosphere soil. The changes of apatite‐P may be more governed by microbial activities (especially mycorrhizal symbiosis) which may be higher in rhizosphere soil compared to soil adhering to root mat.  相似文献   
130.
Direct measurement of unsaturated hydraulic parameters that are crucial inputs in any modeling of water flow or solute transport through the vadose zone is costly and time-consuming. Therefore, indirect methods like artificial neural networks (ANNs) can be used to estimate these parameters. Different ANNs conditions [two training algorithms (Trainlm and Traingd), two transfer functions (Tansig and Logsig), and different combinations of the input variables sand, silt, clay, bulk density (BD), soil organic matter (SOM) and initial (?i) and saturated (?s) volumetric water content] were used to predict the unsaturated hydraulic conductivity, K ψ [at six applied tensions (ψ) of 0–0.2 m] and sorptive number, α (at five ψ values of 0.03–0.2 m) that correspond to 138 soil samples from two neighboring study areas located in the Agricultural College, Shiraz University, Islamic Republic of Iran. A four-layer ANNs with three and four nodes in the hidden layers, performed the best in predicting K ψ and α. Traingd produced the best predictions over all input variables when Tansig and Logsig transfer functions were used for K ψ and α at different values of ψ, respectively. ‘Silt + clay + sand + BD + SOM’ was the most basic influential input variable for predictions of K ψ and α at almost all values of ψ. The accuracy of ANNs-predicted K ψ decreased with decreasing ψ from 0.2 to 0.1 m, followed by an increase to a ψ value of 0 m; a specific relationship was not observed for α. Therefore, ANNs can be used to predict K ψ with greater confidence at moderate values of ψ than at lower or higher values. The normalized root mean square error, NRMSE, confirmed that ANNs predictions for K ψ were more accurate than predictions for α. Because reliable predictions were obtained for K ψ, and to a lesser extent for α, it is recommended that such intelligence models are used to predict these vital soil hydraulic attributes.  相似文献   
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