Cellulose is a linear biopolymer which is composed of nanofibrils,thus having a large surface area.This low-cost,low-density,high-specific-surface-area,easily processable polymer is found in nature in the form of plan...Cellulose is a linear biopolymer which is composed of nanofibrils,thus having a large surface area.This low-cost,low-density,high-specific-surface-area,easily processable polymer is found in nature in the form of plants,bacteria and tunicates.Cellulose has outstanding characteristics including low cytotoxicity,biocompatibility,good mechanical properties,high chemical stability,and cost effectiveness which make them suitable candidates for biomedical applications.The ma-nipulation of cellulose at nanoscale resulted in nanocellulose having exceptional physicochem-ical properties.Therefore,cellulose nanocomposite is a fascinating area of research which has applications in biomedical fields like wound healing,bone tissue engineering,three dimensional printing,drug carriers,medical implants etc.This review is mainly focused on the developments in the generation of cellulose nanocomposites and their potential applications in the biomedical field.展开更多
Piezoelectric materials that generate electrical signals in response to mechanical strain can be used in tissue engineering to stimulate cell proliferation. Poly （vinylidene fluoride-trifluoroethylene） （P（VDF-TrF...Piezoelectric materials that generate electrical signals in response to mechanical strain can be used in tissue engineering to stimulate cell proliferation. Poly （vinylidene fluoride-trifluoroethylene） （P（VDF-TrFE））, a piezoelectric polymer, is widely used in biomaterial applications. We hypothesized that incorporation of zinc oxide （ZnO） nanoparticles into the P（VDF-TrFE） matrix could promote adhesion, migration, and proliferation of cells, as well as blood vessel formation （angiogenesis）. In this study, we fabricated and comprehensively characterized a novel electrospun P（VDF-TrFE）/ZnO nanocomposite tissue engineering scaffold. We analyzed the morphological features of the polymeric matrix by scanning electron microscopy, and utilized Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry to examine changes in the crystalline phases of the copolymer due to addition of the nanoparticles. We detected no or minimal adverse effects of the biomaterials with regard to blood compatibility in vitro, biocompatibility, and cytotoxicity, indicating that P（VDF-TrFE）/ZnO nanocomposite scaffolds are suitable for tissue engineering applications. Interestingly, human mesenchymal stem cells （hMSCs） and human umbilical vein endothelial cells cultured on the nanocomposite scaffolds exhibited higher cell viability, adhesion, and proliferation compared to cells cultured on tissue culture plates or neat P（VDF-TrFE） scaffolds. Nanocomposite scaffolds implanted into rats with or without hMSCs did not elicit immunological responses, as assessed by macroscopic analysis and histology. Importantly, nanocomposite scaffolds promoted angiogenesis, which was increased in scaffolds pre-seeded with hMSCs. Overall, our results highlight the potential of these novel P（VDF-TrFE）/ZnO nanocomposites for use in tissue engineering, due to their biocompatibility and ability to promote cell adhesion and angiogenesis.展开更多
Revised Universal Soil Loss Equation(RUSLE) model coupled with transport limited sediment delivery(TLSD) function was used to predict the longtime average annual soil loss, and to identify the critical erosion-/deposi...Revised Universal Soil Loss Equation(RUSLE) model coupled with transport limited sediment delivery(TLSD) function was used to predict the longtime average annual soil loss, and to identify the critical erosion-/deposition-prone areas in a tropical mountain river basin, viz., Muthirapuzha River Basin(MRB; area=271.75 km^2), in the southern Western Ghats, India. Mean gross soil erosion in MRB is 14.36 t ha^(-1) yr^(-1), whereas mean net soil erosion(i.e., gross erosion-deposition) is only 3.60 t ha^(-1) yr^(-1)(i.e., roughly 25% of the gross erosion). Majority of the basin area(~86%) experiences only slight erosion(<5 t ha^(-1) yr^(-1)), and nearly 3% of the area functions as depositional environment for the eroded sediments(e.g., the terraces of stream reaches, the gentle plains as well as the foot slopes of the plateau scarps and the terrain with concordant summits). Although mean gross soil erosion rates in the natural vegetation belts are relatively higher, compared to agriculture, settlement/built-up areas and tea plantation, the sediment transport efficiency in agricultural areas and tea plantation is significantly high,reflecting the role of human activities on accelerated soil erosion. In MRB, on a mean basis, 0.42 t of soil organic carbon(SOC) content is being eroded per hectare annually, and SOC loss from the 4th order subbasins shows considerable differences, mainly due to the spatial variability in the gross soil erosion rates among the sub-basins. The quantitative results, on soil erosion and deposition, modelled using RUSLE and TLSD, are expected to be beneficial while formulating comprehensive land management strategies for reducing the extent of soil degradation in tropical mountain river basins.展开更多
The rain shadow regions requisite a comprehensive watershed development and management plan for sustainable water resources management. The Pambar River Basin （PRB） lies on the rain shadow region of the southern Wes...The rain shadow regions requisite a comprehensive watershed development and management plan for sustainable water resources management. The Pambar River Basin （PRB） lies on the rain shadow region of the southern Western Ghats, India, where climate showed marked intra-basin variation. A morphometric analysis was done to evaluate the drainage characteristics of PRB using topographical maps and digital elevation data. PRB was divided into eighteen 4th order basins （SB1-SB18）, distributed along various climatic gradients. Lower order streams mostly dominate PRB and drainage pattern is a function of relief and structure. The terrain is highly dissected and prone to soil erosion during heavy storms and the elongated shape of PRB enables easier flood management. The influence of climate on drainage characteristics was evidently emphasized in basin morphometry. Four distinctively different classes were identified based on the morphometric similarities. The significance of morphometric analysis on the hydrological characterization is discussed and the relevance of the present study in water harvesting has been explicated.展开更多
The Muthirapuzha watershed(MW)is one among the major tributaries of Periyarthe longest west flowing river in Kerala,India.A morphometric analysis was carried out to determine the spatial variations in the drainage ch...The Muthirapuzha watershed(MW)is one among the major tributaries of Periyarthe longest west flowing river in Kerala,India.A morphometric analysis was carried out to determine the spatial variations in the drainage characteristics of MW and its 14 fourth order sub-watersheds(SW1SW14)using Survey of India topographic maps and Landsat ETMimagery.The study revealed that the watershed includes a sixth order stream and lower order streams dominate the basin.Results did indicate that rainfall has a significant role in the drainage development whereas structure and relief of rocks dictate the drainage pattern.The asymmetry in the drainage distribution is correlated with the tectonic history of the Munnar plateau in the late Paleocene age.The watershed is moderate to well-drained and exhibited a geomorphic maturity in its physiographic development.The shape parameters revealed the elongated nature of MW and drainage network development in the watershed.Further,the analysis provided significant insight into the terrain characteristics.This study strongly brings to light,(a)the tendency of the watershed to soil loss and(b)the hydrological makeup of the subwatersheds,which combined helped to formulate a comprehensive watershed management plan.展开更多
Manganese-substituted magnetite ferrofluids(FFs)Mnx Fe_(1-x)Fe_(2)O_(4)(x=0–0.8)were prepared in this work through a chemical coprecipitation reaction.The controlled growth of FF nanomaterials for antibacterial activ...Manganese-substituted magnetite ferrofluids(FFs)Mnx Fe_(1-x)Fe_(2)O_(4)(x=0–0.8)were prepared in this work through a chemical coprecipitation reaction.The controlled growth of FF nanomaterials for antibacterial activities is challenging,and therefore,very few reports are available on the topic.This research focuses on stabilizing aqueous FFs with the tetramethylammonium hydroxide surfactant to achieve high homogeneity.Morphological characterization reveals nanoparticles of 5–11 nm formed by the chemical reaction and nanocrystalline nature,as evident from structural investigations.Mn-substituted magnetic FFs are analyzed for their structural,functional,and antibacterial performance according to the Mn-substituent content.Optical studies show a high blue shift for Mn^(2+)-substituted Mnx Fe_(1-x)Fe_(2)O_(4)with the theoretical correlation of optical band gaps with the Mn content.The superparamagnetic nature of substituted FFs causes zero coercivity and remanence,which consequently influence the particle size,cation distribution,and spin canting.The structural and functional performance of the FFs is correlated with the antibacterial activity,finally demonstrating the highest inhibition zone formation for Mnx Fe_(1-x)Fe_(2)O_(4)FFs.展开更多
Congenital heart disease(CHD)is the commonest birth defect,affecting approximately 9.4/1000 live births.^(1)Atrial Septal Defect(ASD)is one of the commonest CHD clinical phenotypes,which frequently requires treatment ...Congenital heart disease(CHD)is the commonest birth defect,affecting approximately 9.4/1000 live births.^(1)Atrial Septal Defect(ASD)is one of the commonest CHD clinical phenotypes,which frequently requires treatment either in childhood or adulthood,and can lead to severe complications such as right heart failure and cardiac arrhythmia.Previous genome-wide association studies(GWAS)have identified a region of chromosome 4p16(Ch4p16)associated with the risk of ASD.展开更多
The author considers a linearly elastic shallow shell with variable thickness and shows that, as the thickness of the shell goes to zero, the solution of the three-dimensional equations converges to the solution of th...The author considers a linearly elastic shallow shell with variable thickness and shows that, as the thickness of the shell goes to zero, the solution of the three-dimensional equations converges to the solution of the two-dimensional shallow shell equations with variable thickness.展开更多
We evaluated nine plastid （matK, rbcL, rpoCl, rpoB, rp136-rpsS, ndhJ, trnL-F, tmrnH-psbA, accD） and two nuclear （ITS and ITS2） barcode loci in family Zingiberaceae by analyzing 60 accessions of 20 species belongin...We evaluated nine plastid （matK, rbcL, rpoCl, rpoB, rp136-rpsS, ndhJ, trnL-F, tmrnH-psbA, accD） and two nuclear （ITS and ITS2） barcode loci in family Zingiberaceae by analyzing 60 accessions of 20 species belonging to seven genera from India. Bidirectional sequences were recovered for every plastid locus by direct sequencing of polymerase chain reaction （PCR） amplicons in all the accessions tested. However, only 35 （58%） and 4o accessions （66~） yielded ITS and ITS2 sequences, respectively, by direct sequencing. In different bioinformatics analyses, matK and rbcL consistently resolved 15 species （75%） into monophyletic groups and five species into two para- phyletic groups. The 173 ITS sequences, including 138 cloned sequences from 23 accessions, discriminated only 12 species （6o%）, and the remaining species were entered into three paraphyletic groups. Phylogenetic and genealogic analyses of plastid and ITS sequences imply the possible occurrence ofnatural hybridizations in the evolutionary past in giving rise to species paraphyly and intragenomic ITS heterogeneity in the species tested. The results support using matK and rbcL loci for barcoding Zingiberaceae members and highlight the poor utility of iTS and the highly regarded ITS2 in barcoding this family, and also caution against proposing ITS loci for barcoding taxa based on limited sampling.展开更多
The effect of photoperiod, temperature, humidity, rainfall and moisture were examined on the annual migration ofLuprops tristis （Fabricius, 1801） （Coleoptera： Tenebrionidae） from rubber plantations to shelters, a...The effect of photoperiod, temperature, humidity, rainfall and moisture were examined on the annual migration ofLuprops tristis （Fabricius, 1801） （Coleoptera： Tenebrionidae） from rubber plantations to shelters, and the induction of 9 months dormancy thereafter. Results confirm the role of rainfall-mediated wetness from summer showers as the cue that induces dormancy in Luprops tristis and provide further proof to the function and significance of moisture in diapause induction in tropical insects. Other factors did not have any significant independent effect on migration and dormancy induction. Reserve food accumulation by teneral adults well ahead of the onset of adverse conditions and the non-return of beetles to the field in short-term favorable conditions strongly indicate that Luprops tristis has evolved the ability to ＂predict＂ and avoid adverse conditions and the inheritance of dormancy-regulating factors from the parent generation.展开更多
Land use and land cover change,perhaps the most significant anthropogenic disturbance to the environment,mainly due to rapid urbanization/industrialization and large scale agricultural activities.In this paper,an atte...Land use and land cover change,perhaps the most significant anthropogenic disturbance to the environment,mainly due to rapid urbanization/industrialization and large scale agricultural activities.In this paper,an attempt has been made to appraise land use/land cover changes over a century(19142007)in the Neyyar River Basin(L56 km;Area483.4 km2)in southern Keralaa biodiversity hot spot in Peninsular India.In this study,digital remote sensing data of the Indian Remote Sensing satellite series I-D(LISS III,20062007)on 1:50,000 scale,Survey of India(SOI)toposheet of 1914(1:63,360)and 1967(1:50,000)have been utilized to map various land use/land cover changes.Maps of different periods have been registered and resampled to similar geographic coordinates using ERDAS Imagine 9.0.The most notable changes include decreases in areas of paddy cultivation,mixed crops,scrub lands and evergreen forests,and increases in built-up areas,rubber plantations,dense mixed forests,and water bodies.Further,large scale exploitation of flood plain mud and river sand have reached menacing proportions leading to bank caving and cut offs at channel bends.Conservation of land and water resources forms an important aspect of ecosystem management in the basin.展开更多
The paper evaluates sensitivity of various spaceborne digital elevation models （DEMs）, viz., Advanced Spaceborne Thermal Emission and Reflection Radiometer （ASTER）, Shuttle Radar Topography Mapping Mission （SRTM...The paper evaluates sensitivity of various spaceborne digital elevation models （DEMs）, viz., Advanced Spaceborne Thermal Emission and Reflection Radiometer （ASTER）, Shuttle Radar Topography Mapping Mission （SRTM） and Global Multi-resolution Terrain Elevation Data 2010 （GMTED）, in comparison with the DEM （TOPO） derived from contour data of 20 m interval of Survey of India topographic sheets of 1 ： 50,000 scale. Several topographic attributes, such as elevation （above mean sea level）, relative relief, slope, aspect, curvature, slope-length and -steepness （LS） factor, terrain ruggedness index （TRI）, topo- graphic wetness index （TWI）, hypsometric integral （lhyp） and drainage network attributes （stream number and stream length） of two tropical mountain river basins, viz. Muthirapuzha River Basin and Pambar River Basin are compared to evaluate the variations. Though the basins are comparable in extent, they differ in respect of terrain characteristics and climate. The result.,; suggest that ASTER and SRTM provide equally reliable representation of topography portrayed by TOP（） and the topographic attributes extracted from the spaceborne DEMs are in agreement with those derived from TOPO. Despite the coarser resolution, SRTM shows relatively higher vertical accuracy （RMSE -- 23 and 20 m respectively in MRB and PRB） compared to ASTER （RMSE - 33 and 24 m） and GMTED （RMSE - 59 and 48 m）. Vertical accuracy of all the spaceborne DEMs is influenced by relief of the terrain as well as type of vegetation. Further, GMTED shows significant deviation for most of the attributes, indicating its inability for mountain-river-basin-scale studies.展开更多
The influence of China’s family planning policies on fertility transition is widely acknowledged in research studies.However,little is known about how improve-ments in women’s education have shaped reproductive deci...The influence of China’s family planning policies on fertility transition is widely acknowledged in research studies.However,little is known about how improve-ments in women’s education have shaped reproductive decisions of Chinese women across different family planning regimes,particularly at micro level.This study uses retrospective pooled birth history data from five consecutive population and fam-ily planning surveys collected over the period 1982-2006 to systematically examine the interrelationship between family planning policies and women’s education,and their interactive effect on the second and third birth transitions.We hypothesize that family planning policies had a differential influence on educational groups in reduc-ing the transition to second and third births.The results from discrete time com-plementary log-log survival models provide strong evidence of differential repro-ductive behavior of education groups across time in China,and the simultaneous influence of women’s education and family planning policies in lowering risks to higher parities.The rates of progression to second and third births tend to be lower after the introduction of rigid family planning policies,and more importantly,the policy impact persisted even after adjusting for demographic and socioeconomic factors.The increase in women’s education overall had a depressing effect on transi-tion to higher parities,and family planning policies implemented overtime have had differential effects on women from different educational groups.The findings show that both family planning policies and women’s education have been instrumental in shaping fertility behavior in China.展开更多
Surface acoustic wave(SAW) devices have been utilized for the sensing of chemical and biological phenomena in microscale for the past few decades. In this study, SAW device was fabricated by electrospinning poly(vinyl...Surface acoustic wave(SAW) devices have been utilized for the sensing of chemical and biological phenomena in microscale for the past few decades. In this study, SAW device was fabricated by electrospinning poly(vinylidenefluoride-co-trifluoroethylene)(P(VDF-TrFE)) incorporated with zinc oxide(ZnO) nanoparticles over the delay line area of the SAW device. The morphology, composition, and crystallinity of P(VDF-TrFE)/ZnO nanocomposites were investigated. After measurement of SAW frequency response, it was found that the insertion loss of the SAW devices incorporated with ZnO nanoparticles was much less than that of the neat polymer-deposited device. The fabricated device was expected to be used in acoustic biosensors to detect and quantify the cell proliferation in cell culture systems.展开更多
Soil erosion and deposition in a tropical mountainous river basin, viz., Pambar River Basin (PRB), in a rain shadow region of the southern Western Ghats (India) were modelled using Revised Universal Soil Loss Equation...Soil erosion and deposition in a tropical mountainous river basin, viz., Pambar River Basin (PRB), in a rain shadow region of the southern Western Ghats (India) were modelled using Revised Universal Soil Loss Equation (RUSLE) and transport limited sediment delivery (TLSD) function in GIS. Mean gross soil erosion in the basin is 11.70 t ha-1 yr-1, and is comparable with the results of previous soil erosion studies from the region. However, mean net soil erosion from the basin is 2.92 t ha-1 yr-1 only, which is roughly 25%of the gross soil erosion. Although natural vegetation belts show relatively higher gross- and net-soil erosion rates (mainly due to high LS and C factors), their sediment transport efficiency is remarkably less, compared to the land use/ land cover types with anthropogenic signatures (i.e., plantations and crop-lands). Despite the lesser amount of annual rainfall, the high rates of soil loss from the semi-arid areas of the basin might be the result of the poor protective vegetation cover as well as isolated high intensity rainfall events. The study highlights the significance of climate-specific plans for soil erosion manage-ment and conservation of the soil resources of the basins developed in rain shadow regions.展开更多
When Eric Fawcett and Reginald Gibson discovered polyethylene accidentally,they never realized how useful their discovery will be for mankind,similar to how Charles Goodyear’s idea of adding sulphur to polyisoprene w...When Eric Fawcett and Reginald Gibson discovered polyethylene accidentally,they never realized how useful their discovery will be for mankind,similar to how Charles Goodyear’s idea of adding sulphur to polyisoprene would revolutionize the tire and other rubber industries.Although those discoveries centuries ago have never realized their current impact,however,the fact is undeniable on how polymer science has conquered the world,gaining an irreplaceable position from a utilitarian perspective.We are currently bombarded with multifarious polymer compositions which differ on the basis of source,origin,and dimensions.展开更多
The beginning of the 21st century witnessed unprecedented economic and social transformation across the globe,underpinned by a steady rise in human and social capital,and per-capita income.Rapid urbanisation,industria...The beginning of the 21st century witnessed unprecedented economic and social transformation across the globe,underpinned by a steady rise in human and social capital,and per-capita income.Rapid urbanisation,industrialisation and modernisation have also created the so-called middle-class boom in Asian societies,triggering family change driven by higher aspirations,modern lifestyles and new forms of consumer behaviour.On the other hand,economic and social inequalities have almost simultaneously widened across different social strata,increasing the complexity of family structures and living arrangements.展开更多
Lanthanum malonate crystals were grown by single tube ionic diffusion through silica gel. The crystallinity of the grown crystals was analyzed by powder X-ray diffraction studies. Fourier transform infrared spectrosco...Lanthanum malonate crystals were grown by single tube ionic diffusion through silica gel. The crystallinity of the grown crystals was analyzed by powder X-ray diffraction studies. Fourier transform infrared spectroscopy （FTIR） and fourier transform （FT） Raman studies confirmed the presence of functional groups in the title compound. The optical band gap energy of the material was extracted from diffuse reflectance spectrum.展开更多
Bulk metallic glass matrix composites are advocated to be material of future owing to their superior strength, hardness and elastic strain limit. However, they possess poor toughness which makes them unusable in any s...Bulk metallic glass matrix composites are advocated to be material of future owing to their superior strength, hardness and elastic strain limit. However, they possess poor toughness which makes them unusable in any structural engineering application. Inoculation has been used as effective mean to overcome this problem. Zr47.5Cu45.5Al5Co2 bulk metallic glass matrix composites (BMGMC) inoculated with ZrC have shown considerable refinement in microstructure owing to heterogeneous nucleation. Efforts have also been made to exploit modern laser-based metal additive manufacturing to fabricate BMGMC parts in one step. However, the effect of laser on inoculated material is unknown. In this study, an effort has been made to apply single pass laser surface treatment on untreated and inoculated BMGMC samples. It is observed that laser treatment not only refine the microstructure but result in change of size, morphology and dispersion of CuZr B2 phase in base metal, heat affected zone and fusion zone in Zr47.5Cu45.5Al5Co2. A similar effect is observed for β-Zr and Zr2Cu in non-inoculated Zr65Cu15Al10Ni10. This effect is documented with back scatter electron imaging.展开更多
文摘Cellulose is a linear biopolymer which is composed of nanofibrils,thus having a large surface area.This low-cost,low-density,high-specific-surface-area,easily processable polymer is found in nature in the form of plants,bacteria and tunicates.Cellulose has outstanding characteristics including low cytotoxicity,biocompatibility,good mechanical properties,high chemical stability,and cost effectiveness which make them suitable candidates for biomedical applications.The ma-nipulation of cellulose at nanoscale resulted in nanocellulose having exceptional physicochem-ical properties.Therefore,cellulose nanocomposite is a fascinating area of research which has applications in biomedical fields like wound healing,bone tissue engineering,three dimensional printing,drug carriers,medical implants etc.This review is mainly focused on the developments in the generation of cellulose nanocomposites and their potential applications in the biomedical field.
文摘Piezoelectric materials that generate electrical signals in response to mechanical strain can be used in tissue engineering to stimulate cell proliferation. Poly （vinylidene fluoride-trifluoroethylene） （P（VDF-TrFE））, a piezoelectric polymer, is widely used in biomaterial applications. We hypothesized that incorporation of zinc oxide （ZnO） nanoparticles into the P（VDF-TrFE） matrix could promote adhesion, migration, and proliferation of cells, as well as blood vessel formation （angiogenesis）. In this study, we fabricated and comprehensively characterized a novel electrospun P（VDF-TrFE）/ZnO nanocomposite tissue engineering scaffold. We analyzed the morphological features of the polymeric matrix by scanning electron microscopy, and utilized Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry to examine changes in the crystalline phases of the copolymer due to addition of the nanoparticles. We detected no or minimal adverse effects of the biomaterials with regard to blood compatibility in vitro, biocompatibility, and cytotoxicity, indicating that P（VDF-TrFE）/ZnO nanocomposite scaffolds are suitable for tissue engineering applications. Interestingly, human mesenchymal stem cells （hMSCs） and human umbilical vein endothelial cells cultured on the nanocomposite scaffolds exhibited higher cell viability, adhesion, and proliferation compared to cells cultured on tissue culture plates or neat P（VDF-TrFE） scaffolds. Nanocomposite scaffolds implanted into rats with or without hMSCs did not elicit immunological responses, as assessed by macroscopic analysis and histology. Importantly, nanocomposite scaffolds promoted angiogenesis, which was increased in scaffolds pre-seeded with hMSCs. Overall, our results highlight the potential of these novel P（VDF-TrFE）/ZnO nanocomposites for use in tissue engineering, due to their biocompatibility and ability to promote cell adhesion and angiogenesis.
基金Financial support from Kerala State Council for Science, Technology, and Environment (004/FSHP/05KSCSTE)
文摘Revised Universal Soil Loss Equation(RUSLE) model coupled with transport limited sediment delivery(TLSD) function was used to predict the longtime average annual soil loss, and to identify the critical erosion-/deposition-prone areas in a tropical mountain river basin, viz., Muthirapuzha River Basin(MRB; area=271.75 km^2), in the southern Western Ghats, India. Mean gross soil erosion in MRB is 14.36 t ha^(-1) yr^(-1), whereas mean net soil erosion(i.e., gross erosion-deposition) is only 3.60 t ha^(-1) yr^(-1)(i.e., roughly 25% of the gross erosion). Majority of the basin area(~86%) experiences only slight erosion(<5 t ha^(-1) yr^(-1)), and nearly 3% of the area functions as depositional environment for the eroded sediments(e.g., the terraces of stream reaches, the gentle plains as well as the foot slopes of the plateau scarps and the terrain with concordant summits). Although mean gross soil erosion rates in the natural vegetation belts are relatively higher, compared to agriculture, settlement/built-up areas and tea plantation, the sediment transport efficiency in agricultural areas and tea plantation is significantly high,reflecting the role of human activities on accelerated soil erosion. In MRB, on a mean basis, 0.42 t of soil organic carbon(SOC) content is being eroded per hectare annually, and SOC loss from the 4th order subbasins shows considerable differences, mainly due to the spatial variability in the gross soil erosion rates among the sub-basins. The quantitative results, on soil erosion and deposition, modelled using RUSLE and TLSD, are expected to be beneficial while formulating comprehensive land management strategies for reducing the extent of soil degradation in tropical mountain river basins.
文摘The rain shadow regions requisite a comprehensive watershed development and management plan for sustainable water resources management. The Pambar River Basin （PRB） lies on the rain shadow region of the southern Western Ghats, India, where climate showed marked intra-basin variation. A morphometric analysis was done to evaluate the drainage characteristics of PRB using topographical maps and digital elevation data. PRB was divided into eighteen 4th order basins （SB1-SB18）, distributed along various climatic gradients. Lower order streams mostly dominate PRB and drainage pattern is a function of relief and structure. The terrain is highly dissected and prone to soil erosion during heavy storms and the elongated shape of PRB enables easier flood management. The influence of climate on drainage characteristics was evidently emphasized in basin morphometry. Four distinctively different classes were identified based on the morphometric similarities. The significance of morphometric analysis on the hydrological characterization is discussed and the relevance of the present study in water harvesting has been explicated.
文摘The Muthirapuzha watershed(MW)is one among the major tributaries of Periyarthe longest west flowing river in Kerala,India.A morphometric analysis was carried out to determine the spatial variations in the drainage characteristics of MW and its 14 fourth order sub-watersheds(SW1SW14)using Survey of India topographic maps and Landsat ETMimagery.The study revealed that the watershed includes a sixth order stream and lower order streams dominate the basin.Results did indicate that rainfall has a significant role in the drainage development whereas structure and relief of rocks dictate the drainage pattern.The asymmetry in the drainage distribution is correlated with the tectonic history of the Munnar plateau in the late Paleocene age.The watershed is moderate to well-drained and exhibited a geomorphic maturity in its physiographic development.The shape parameters revealed the elongated nature of MW and drainage network development in the watershed.Further,the analysis provided significant insight into the terrain characteristics.This study strongly brings to light,(a)the tendency of the watershed to soil loss and(b)the hydrological makeup of the subwatersheds,which combined helped to formulate a comprehensive watershed management plan.
基金the financial assistance provided by the Indian Council of Medical Research in the form of a research associate (No.5/3/8/95/ITR F/2020)。
文摘Manganese-substituted magnetite ferrofluids(FFs)Mnx Fe_(1-x)Fe_(2)O_(4)(x=0–0.8)were prepared in this work through a chemical coprecipitation reaction.The controlled growth of FF nanomaterials for antibacterial activities is challenging,and therefore,very few reports are available on the topic.This research focuses on stabilizing aqueous FFs with the tetramethylammonium hydroxide surfactant to achieve high homogeneity.Morphological characterization reveals nanoparticles of 5–11 nm formed by the chemical reaction and nanocrystalline nature,as evident from structural investigations.Mn-substituted magnetic FFs are analyzed for their structural,functional,and antibacterial performance according to the Mn-substituent content.Optical studies show a high blue shift for Mn^(2+)-substituted Mnx Fe_(1-x)Fe_(2)O_(4)with the theoretical correlation of optical band gaps with the Mn content.The superparamagnetic nature of substituted FFs causes zero coercivity and remanence,which consequently influence the particle size,cation distribution,and spin canting.The structural and functional performance of the FFs is correlated with the antibacterial activity,finally demonstrating the highest inhibition zone formation for Mnx Fe_(1-x)Fe_(2)O_(4)FFs.
基金supported by The University of Manchester-Peking University Health Science Centre Alliance,the China Scholarships Council,and British Heart Foundation Programme Grant RG/15/12/31616.
文摘Congenital heart disease(CHD)is the commonest birth defect,affecting approximately 9.4/1000 live births.^(1)Atrial Septal Defect(ASD)is one of the commonest CHD clinical phenotypes,which frequently requires treatment either in childhood or adulthood,and can lead to severe complications such as right heart failure and cardiac arrhythmia.Previous genome-wide association studies(GWAS)have identified a region of chromosome 4p16(Ch4p16)associated with the risk of ASD.
文摘The author considers a linearly elastic shallow shell with variable thickness and shows that, as the thickness of the shell goes to zero, the solution of the three-dimensional equations converges to the solution of the two-dimensional shallow shell equations with variable thickness.
基金financial support (BT/ PR8349/NDB/51/136/2006 19/01/2007–19-01/2010) from the Department of Biotechnology, Government of India
文摘We evaluated nine plastid （matK, rbcL, rpoCl, rpoB, rp136-rpsS, ndhJ, trnL-F, tmrnH-psbA, accD） and two nuclear （ITS and ITS2） barcode loci in family Zingiberaceae by analyzing 60 accessions of 20 species belonging to seven genera from India. Bidirectional sequences were recovered for every plastid locus by direct sequencing of polymerase chain reaction （PCR） amplicons in all the accessions tested. However, only 35 （58%） and 4o accessions （66~） yielded ITS and ITS2 sequences, respectively, by direct sequencing. In different bioinformatics analyses, matK and rbcL consistently resolved 15 species （75%） into monophyletic groups and five species into two para- phyletic groups. The 173 ITS sequences, including 138 cloned sequences from 23 accessions, discriminated only 12 species （6o%）, and the remaining species were entered into three paraphyletic groups. Phylogenetic and genealogic analyses of plastid and ITS sequences imply the possible occurrence ofnatural hybridizations in the evolutionary past in giving rise to species paraphyly and intragenomic ITS heterogeneity in the species tested. The results support using matK and rbcL loci for barcoding Zingiberaceae members and highlight the poor utility of iTS and the highly regarded ITS2 in barcoding this family, and also caution against proposing ITS loci for barcoding taxa based on limited sampling.
文摘The effect of photoperiod, temperature, humidity, rainfall and moisture were examined on the annual migration ofLuprops tristis （Fabricius, 1801） （Coleoptera： Tenebrionidae） from rubber plantations to shelters, and the induction of 9 months dormancy thereafter. Results confirm the role of rainfall-mediated wetness from summer showers as the cue that induces dormancy in Luprops tristis and provide further proof to the function and significance of moisture in diapause induction in tropical insects. Other factors did not have any significant independent effect on migration and dormancy induction. Reserve food accumulation by teneral adults well ahead of the onset of adverse conditions and the non-return of beetles to the field in short-term favorable conditions strongly indicate that Luprops tristis has evolved the ability to ＂predict＂ and avoid adverse conditions and the inheritance of dormancy-regulating factors from the parent generation.
文摘Land use and land cover change,perhaps the most significant anthropogenic disturbance to the environment,mainly due to rapid urbanization/industrialization and large scale agricultural activities.In this paper,an attempt has been made to appraise land use/land cover changes over a century(19142007)in the Neyyar River Basin(L56 km;Area483.4 km2)in southern Keralaa biodiversity hot spot in Peninsular India.In this study,digital remote sensing data of the Indian Remote Sensing satellite series I-D(LISS III,20062007)on 1:50,000 scale,Survey of India(SOI)toposheet of 1914(1:63,360)and 1967(1:50,000)have been utilized to map various land use/land cover changes.Maps of different periods have been registered and resampled to similar geographic coordinates using ERDAS Imagine 9.0.The most notable changes include decreases in areas of paddy cultivation,mixed crops,scrub lands and evergreen forests,and increases in built-up areas,rubber plantations,dense mixed forests,and water bodies.Further,large scale exploitation of flood plain mud and river sand have reached menacing proportions leading to bank caving and cut offs at channel bends.Conservation of land and water resources forms an important aspect of ecosystem management in the basin.
基金Financial support from Kerala State Council for Science,Technology,and Environment,Thiruvananthapuram and permission for the field studies in the protected areas by Kerala Forest Department
文摘The paper evaluates sensitivity of various spaceborne digital elevation models （DEMs）, viz., Advanced Spaceborne Thermal Emission and Reflection Radiometer （ASTER）, Shuttle Radar Topography Mapping Mission （SRTM） and Global Multi-resolution Terrain Elevation Data 2010 （GMTED）, in comparison with the DEM （TOPO） derived from contour data of 20 m interval of Survey of India topographic sheets of 1 ： 50,000 scale. Several topographic attributes, such as elevation （above mean sea level）, relative relief, slope, aspect, curvature, slope-length and -steepness （LS） factor, terrain ruggedness index （TRI）, topo- graphic wetness index （TWI）, hypsometric integral （lhyp） and drainage network attributes （stream number and stream length） of two tropical mountain river basins, viz. Muthirapuzha River Basin and Pambar River Basin are compared to evaluate the variations. Though the basins are comparable in extent, they differ in respect of terrain characteristics and climate. The result.,; suggest that ASTER and SRTM provide equally reliable representation of topography portrayed by TOP（） and the topographic attributes extracted from the spaceborne DEMs are in agreement with those derived from TOPO. Despite the coarser resolution, SRTM shows relatively higher vertical accuracy （RMSE -- 23 and 20 m respectively in MRB and PRB） compared to ASTER （RMSE - 33 and 24 m） and GMTED （RMSE - 59 and 48 m）. Vertical accuracy of all the spaceborne DEMs is influenced by relief of the terrain as well as type of vegetation. Further, GMTED shows significant deviation for most of the attributes, indicating its inability for mountain-river-basin-scale studies.
基金support for this research was provided by the UK Economic and Social Research Council(Reference:ES/J500161/1).
文摘The influence of China’s family planning policies on fertility transition is widely acknowledged in research studies.However,little is known about how improve-ments in women’s education have shaped reproductive decisions of Chinese women across different family planning regimes,particularly at micro level.This study uses retrospective pooled birth history data from five consecutive population and fam-ily planning surveys collected over the period 1982-2006 to systematically examine the interrelationship between family planning policies and women’s education,and their interactive effect on the second and third birth transitions.We hypothesize that family planning policies had a differential influence on educational groups in reduc-ing the transition to second and third births.The results from discrete time com-plementary log-log survival models provide strong evidence of differential repro-ductive behavior of education groups across time in China,and the simultaneous influence of women’s education and family planning policies in lowering risks to higher parities.The rates of progression to second and third births tend to be lower after the introduction of rigid family planning policies,and more importantly,the policy impact persisted even after adjusting for demographic and socioeconomic factors.The increase in women’s education overall had a depressing effect on transi-tion to higher parities,and family planning policies implemented overtime have had differential effects on women from different educational groups.The findings show that both family planning policies and women’s education have been instrumental in shaping fertility behavior in China.
基金the Agence Nationale de la Recherche for the financial support (ANR-12-BS09021)the Department of Biotechnology (DBT), Government of India, New Delhi, for the financial support through MSUB IPLSARE Program (BT/PR4800/INF/22/152/2012)
文摘Surface acoustic wave(SAW) devices have been utilized for the sensing of chemical and biological phenomena in microscale for the past few decades. In this study, SAW device was fabricated by electrospinning poly(vinylidenefluoride-co-trifluoroethylene)(P(VDF-TrFE)) incorporated with zinc oxide(ZnO) nanoparticles over the delay line area of the SAW device. The morphology, composition, and crystallinity of P(VDF-TrFE)/ZnO nanocomposites were investigated. After measurement of SAW frequency response, it was found that the insertion loss of the SAW devices incorporated with ZnO nanoparticles was much less than that of the neat polymer-deposited device. The fabricated device was expected to be used in acoustic biosensors to detect and quantify the cell proliferation in cell culture systems.
文摘Soil erosion and deposition in a tropical mountainous river basin, viz., Pambar River Basin (PRB), in a rain shadow region of the southern Western Ghats (India) were modelled using Revised Universal Soil Loss Equation (RUSLE) and transport limited sediment delivery (TLSD) function in GIS. Mean gross soil erosion in the basin is 11.70 t ha-1 yr-1, and is comparable with the results of previous soil erosion studies from the region. However, mean net soil erosion from the basin is 2.92 t ha-1 yr-1 only, which is roughly 25%of the gross soil erosion. Although natural vegetation belts show relatively higher gross- and net-soil erosion rates (mainly due to high LS and C factors), their sediment transport efficiency is remarkably less, compared to the land use/ land cover types with anthropogenic signatures (i.e., plantations and crop-lands). Despite the lesser amount of annual rainfall, the high rates of soil loss from the semi-arid areas of the basin might be the result of the poor protective vegetation cover as well as isolated high intensity rainfall events. The study highlights the significance of climate-specific plans for soil erosion manage-ment and conservation of the soil resources of the basins developed in rain shadow regions.
文摘When Eric Fawcett and Reginald Gibson discovered polyethylene accidentally,they never realized how useful their discovery will be for mankind,similar to how Charles Goodyear’s idea of adding sulphur to polyisoprene would revolutionize the tire and other rubber industries.Although those discoveries centuries ago have never realized their current impact,however,the fact is undeniable on how polymer science has conquered the world,gaining an irreplaceable position from a utilitarian perspective.We are currently bombarded with multifarious polymer compositions which differ on the basis of source,origin,and dimensions.
文摘The beginning of the 21st century witnessed unprecedented economic and social transformation across the globe,underpinned by a steady rise in human and social capital,and per-capita income.Rapid urbanisation,industrialisation and modernisation have also created the so-called middle-class boom in Asian societies,triggering family change driven by higher aspirations,modern lifestyles and new forms of consumer behaviour.On the other hand,economic and social inequalities have almost simultaneously widened across different social strata,increasing the complexity of family structures and living arrangements.
文摘Lanthanum malonate crystals were grown by single tube ionic diffusion through silica gel. The crystallinity of the grown crystals was analyzed by powder X-ray diffraction studies. Fourier transform infrared spectroscopy （FTIR） and fourier transform （FT） Raman studies confirmed the presence of functional groups in the title compound. The optical band gap energy of the material was extracted from diffuse reflectance spectrum.
文摘Bulk metallic glass matrix composites are advocated to be material of future owing to their superior strength, hardness and elastic strain limit. However, they possess poor toughness which makes them unusable in any structural engineering application. Inoculation has been used as effective mean to overcome this problem. Zr47.5Cu45.5Al5Co2 bulk metallic glass matrix composites (BMGMC) inoculated with ZrC have shown considerable refinement in microstructure owing to heterogeneous nucleation. Efforts have also been made to exploit modern laser-based metal additive manufacturing to fabricate BMGMC parts in one step. However, the effect of laser on inoculated material is unknown. In this study, an effort has been made to apply single pass laser surface treatment on untreated and inoculated BMGMC samples. It is observed that laser treatment not only refine the microstructure but result in change of size, morphology and dispersion of CuZr B2 phase in base metal, heat affected zone and fusion zone in Zr47.5Cu45.5Al5Co2. A similar effect is observed for β-Zr and Zr2Cu in non-inoculated Zr65Cu15Al10Ni10. This effect is documented with back scatter electron imaging.
