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251.
The structure and properties of chicken feather barbs makes them unique fibers preferable for several applications. The presence
of hollow honeycomb structures, their low density, high flexibility and possible structural interaction with other fibers
when made into products such as textiles provides them unique properties unlike any other natural or synthetic fibers. No
literature is available on the physical structure and tensile properties of chicken feather barbs. In this study, we report
the physical and morphological structure and the properties of chicken feather barbs for potential use as natural protein
fibers. The morphological structure of chicken feather barbs is similar to that of the rachis but the physical structure of
the protein crystals in chicken feather barbs is different than that reported for feather rachis keratin. The tensile properties
of barbs in terms of their strength and modulus are similar but the elongation is lower than that of wool. Using the cheap
and abundant feathers as protein fibers will conserve the energy, benefit the environment and also make the fiber industry
more sustainable 相似文献
252.
Fetal death occurs in 15% of clinically recognized pregnancies. Cytogenetic abnormalities are present in 50% of spontaneous abortions (fetal deaths < 20 weeks) whereas the rate is 6% to 13% for stillbirths (fetal deaths ≥ 20 weeks). Microarray has been demonstrated to increase the diagnosis of genetic abnormalities by providing coverage of the entire genome at a higher density, detecting as small as 50 to 100 kb deletions or duplications, known as copy number changes. Microarray is particularly suited for evaluation of fetal death because DNA can still be analyzed in macerated fetuses and nonviable tissue, two situations where culturing and karyotyping is known to have low yield. Microarray has already proven successful in providing additional genetic information beyond karyotype in spontaneous abortion. The few studies on the use of microarray in stillbirth evaluation have been promising, demonstrating an increase in the diagnosis of clinically relevant genetic abnormalities when compared with karyotype. As the cost and technology improve, microarray may ultimately become the first line screen for genetic abnormalities in stillbirth. The accurate diagnosis of a genetic abnormality as the cause for fetal death may provide closure for families, prevent unnecessary treatments, and enable clinicians to more accurately counsel and manage subsequent pregnancies. © 2012 John Wiley & Sons, Ltd. 相似文献
253.
Stuart Mires Snigdha Reddy Clare Skerritt Massimo Caputo Kelly-Ann Eastwood 《黑龙江环境通报》2023,43(5):647-660
Aetiological understanding and screening methods for congenital heart disease (CHD) are limited. Maternal metabolomic assessment offers the potential to identify risk factors and biomarkers. We performed a systematic review (PROSPERO CRD42022308452) investigating the association between fetal/childhood CHD and endogenous maternal metabolites. Ovid-MEDLINE, Ovid-EMBASE and Cochrane Library were searched between inception and 06/09/2022. Case control studies included analysing maternal blood or urine metabolites in pregnancy or postpartum where there was foetal/childhood CHD. Risk of bias assessment utilised the Scottish Intercollegiate Guidelines Network methodology checklist and narrative synthesis was performed. A total of 134 records were screened with eight eligible studies (n = 3242 pregnancies, n = 842 CHD-affected offspring). Five studies performed metabolomic analysis in pregnancy. Metabolites distinguishing case and control groups spanned lipid, glucose and amino-acid pathways, with the development of sensitive risk prediction models. No single metabolite consistently distinguished cases and controls across studies. Three studies performed targeted analysis postnatally with altered lipid and amino acid metabolites and raised homocysteine and markers of oxidative stress identified in cases. Included studies reported small sample sizes, analysing different biosamples at variable time points using differing techniques. At present, there is not enough evidence to confidently associate maternal metabolomic profiles with offspring CHD risk. However, several identified pathways warrant further investigation. 相似文献
254.
Studies about wetlands have been identified as a key component of environmental change. The present study assesses the spatio-temporal changes in the wetlands of the Great Rann of Kachchh, in the Kachchh Biosphere Reserve, India, using remote sensing and GIS techniques. Satellite time-series data from Landsat (1977, 1990 and 1999) and IRS P6 (2006, 2008–2012) were used. The Normalised Difference Water Index (NDWI) was derived for each year and the layers were manually edited to obtain a high classification accuracy. The analysis found that the area has undergone considerable change from 1977 to 2011. The natural wetland area of 30.6 km2 was converted to salt pans. An area of about 255 km2 (41.6 %) of natural grassland was invaded by Prosopis juliflora, which raises further conservation concerns and emphasises the importance of having intervention plans to manage this ecosystem. The highest water spread of 1171 km2 was observed in September 2011, followed by 2010, 2009 and 2008 in the same month. The present study is useful in planning the long-term management and conservation of the Great Rann of Kachchh wetland. 相似文献
255.
Jiwan SINGH Yoon-Young CHANG Jae-Kyu YANG Seon-Hong KANG Janardhan Reddy KODURU 《Frontiers of Environmental Science & Engineering》2016,10(4):9
Phenol removal by n/m Fe in the presence of H2O2 was highly effective.
Increasing the amounts of n/m Fe and H2O2?increased the phenol removal rate.
Phenol removal was decreased with an increase in the concentration of phenol.
The natural pH (6.9) of the solution was highly effective for phenol removal.
The pseudo-first-order kinetics was best fitted for the degradation of phenol.
The study investigates the magnetic separation of Fe from automobile shredder residue (ASR) (<0.25 mm) and its application for phenol degradation in water. The magnetically separated Fe was subjected to an ultrasonically assisted acid treatment, and the degradation of phenol in an aqueous solution using nano/micro-size Fe (n/m Fe) was investigated in an effort to evaluate the possibility of utilizing n/m Fe to remove phenol from wastewater. The prepared n/m Fe was analyzed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The effects of the dosages of n/mFe, pH, concentration of phenol and amount of H2O2 on phenol removal were evaluated. The results confirm that the phenol degradation rate was improved with an increase in the dosages of n/mFe and H2O2; however, the rate is reduced when the phenol concentration is higher. The degradation of phenol by n/mFe followed the pseudo-first-order kinetics. The value of the reaction rate constant (k) was increased as the amounts of n/m Fe and H2O2 increased. Conversely, the value of k was reduced when the concentration of phenol was increased. The probable mechanism behind the degradation of phenol by n/m Fe is the oxidation of phenol through hydroxyl radicals which are produced during the reaction between H2O2 and n/m Fe. 相似文献
256.
Radhakrishna M Reddy MK Krishna DR 《Journal of environmental biology / Academy of Environmental Biology, India》2007,28(4):865-867
HIV/AIDS pandemic has devastated many countries reversing national development; HIV was not seen in Asia and India till 1980. Now India has become epicenter of AIDS pandemic. During April 2002 to March 2003 the HIV+ ve pregnant women and their husbands were encouraged to enroll in the prospective study with informed consent. The study results consist of most of the females who are in the age group between 16-25 years who were affected by HIV High infection is observed in people with lower socio-economic and education background. High infection rate is observed in house wives (26.7%), laborers (23%) and agricultural workers (12.1%) followed by toddy tapers (5%), drivers (5.96%) and others (6 47%). HIV +ve subjects at Mother To Child Transmission (MTCT) centers are surprisingly clinically very healthy. No disease manifestation was noticed. 相似文献
257.
The degradation of a widely used organophosphorus insecticide, monocrotophos (dimethyl (E)-1-methyl-2-methylcarbamoyl vinyl phosphate) in two Indian agricultural soils at two concentration levels, 10 and 100 microg g(-1) soil under aerobic conditions at 60% water-holding capacity at 28+/-4 degrees C was studied in a laboratory. The degradation of monocrotophos at both concentrations in black vertisol and red alfinsol soils was rapid accounting for 96-98% of the applied quantity and followed the first-order kinetics with rate constants (k) of 0.0753 and 0.0606 day(-1) and half-lives (t1/2) of 9.2 and 11.4 days, respectively. Degradation of monocrotophos in soils proceeded by hydrolysis with formation of N-methylacetoacetamide. Even three additions of monocrotophos at 10 microg g(-1) soil did not result in its enhanced degradation. However, there was cumulative accumulation of N-methylacetoacetamide in soils pretreated with monocrotophos to the tune of 7-15 microg g(-1) soil. Both biotic and abiotic factors were involved in degradation of monocrotophos in soils. 相似文献
258.
The biosorption of heavy metals is considered to be one of the best alternatives for the treatment of wastewater. The metal binding capacity of algae and acid-treated algae is investigated to find out the removal characteristics of Cr(VI), Ni(II) and Cu(II) ions from single metal solutions. Batch experiments are conducted and the study is extended to investigate the effect of pH, amount of adsorbent and adsorbate concentration on the extent of biosorption. The results indicate that the adsorption capacity of algae depends strongly on pH. The maximum adsorption of Cr(VI), Ni(II) and Cu(II) occurs at pH values of 2, 7 and 4.3, respectively. The adsorption process follows first-order kinetic equation. The data obtained are correlated with Freundlich and Langmuir adsorption isotherms. 相似文献
259.
According to official statistics, a large percentage of crashes in Portugal are reported on urban roads. For instance, from 2004 to 2007, about 70% of all injury accidents and 43% of the fatalities occurred inside urban agglomerations. This important safety problem has also been observed on the urban network of Lisbon. Understanding this significant problem, the Government of the Portuguese Republic via its research grant agency – The Foundation for Science and Technology – funded a project whose primary objective consists of developing tools that would help estimating the safety performance of various components of the urban highway system in Lisbon. This paper documents one component of the safety tools that were developed and describes the steps that were taken to develop predictive models for estimating the safety performance of signalized and unsignalized intersections of Lisbon. Several crash predictive models were developed using the Poisson-gamma modeling framework. Two types of models were estimated: flow-only and models with covariates. They were estimated using crash and other related data collected at 44 three-legged and 50 four-legged intersections for the years 2004–2007, inclusively. It was found that some highway geometric design characteristics were associated with the crashes occurring at urban three- and four-legged intersections in Lisbon. 相似文献
260.
This paper reports the structure and properties of silk fibers produced by Actias lunas in comparison to Bombyx mori and the common wild silks. Considerable efforts are being made to find new sources for natural silk and also to develop regenerated protein fibers to supplement the limited amounts of B. mori and wild silks available in the market. In addition, it has been found that non-traditional silks have unique properties and utilizing uncommon wild silks can provide income and employment to indigenous people where the wild silks are found. Actias lunas belongs to the Saturniidae family of silk producing insects. However, the structure and properties of silk produced by A. lunas have not been studied. This research showed that the silk fibers produced by the luna moth had morphological and physical structure similar to that of the common wild silks but tensile properties similar to that of B. mori silk. A. lunas silk fibers are composed of higher amounts of hydrophobic amino acids and had much less glycine than B. mori and common wild silks. With a fineness of 2 denier, breaking tenacity of 4.3?g/den and breaking elongation of 10.9?%, the tensile properties of A. lunas silk fibers were similar to that of B. mori and much better than that of the common wild silks that are coarser and have lower breaking tenacity. A. lunas fibers show good potential to be useful for applications currently using B. mori silk. 相似文献