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1.
Nature ; 627(8002): 73-79, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38418887

RESUMO

By directly altering microscopic interactions, pressure provides a powerful tuning knob for the exploration of condensed phases and geophysical phenomena1. The megabar regime represents an interesting frontier, in which recent discoveries include high-temperature superconductors, as well as structural and valence phase transitions2-6. However, at such high pressures, many conventional measurement techniques fail. Here we demonstrate the ability to perform local magnetometry inside a diamond anvil cell with sub-micron spatial resolution at megabar pressures. Our approach uses a shallow layer of nitrogen-vacancy colour centres implanted directly within the anvil7-9; crucially, we choose a crystal cut compatible with the intrinsic symmetries of the nitrogen-vacancy centre to enable functionality at megabar pressures. We apply our technique to characterize a recently discovered hydride superconductor, CeH9 (ref. 10). By performing simultaneous magnetometry and electrical transport measurements, we observe the dual signatures of superconductivity: diamagnetism characteristic of the Meissner effect and a sharp drop of the resistance to near zero. By locally mapping both the diamagnetic response and flux trapping, we directly image the geometry of superconducting regions, showing marked inhomogeneities at the micron scale. Our work brings quantum sensing to the megabar frontier and enables the closed-loop optimization of superhydride materials synthesis.

2.
Nature ; 597(7874): 45-50, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34471276

RESUMO

Conventional wisdom holds that macroscopic classical phenomena naturally emerge from microscopic quantum laws1-7. However, despite this mantra, building direct connections between these two descriptions has remained an enduring scientific challenge. In particular, it is difficult to quantitatively predict the emergent 'classical' properties of a system (for example, diffusivity, viscosity and compressibility) from a generic microscopic quantum Hamiltonian7-14. Here we introduce a hybrid solid-state spin platform, where the underlying disordered, dipolar quantum Hamiltonian gives rise to the emergence of unconventional spin diffusion at nanometre length scales. In particular, the combination of positional disorder and on-site random fields leads to diffusive dynamics that are Fickian yet non-Gaussian15-20. Finally, by tuning the underlying parameters within the spin Hamiltonian via a combination of static and driven fields, we demonstrate direct control over the emergent spin diffusion coefficient. Our work enables the investigation of hydrodynamics in many-body quantum spin systems.

3.
Environ Geochem Health ; 45(11): 7979-7997, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37515727

RESUMO

Nutrient management in resource conservation practices influence the structural and functional microbial diversities and thereby affect biological processes and biochemical properties in soil. We studied the long-term effects of resource conservation technologies on functional microbial diversity and their interactions with soil biochemical properties and enzymatic activities in tropical rice-green gram cropping system. The experiment includes seven treatments viz., conventional practice (CC), brown manuring (BM), green manuring (GM), wet direct drum sowing, zero tillage, green manuring-customized leaf colour chart based-N application (GM-CLCC-N) and biochar (BC) application. The result of the present study revealed that microbial biomass nitrogen (N), carbon (C) and phosphorus (P) in GM practice were increased by 23.3, 37.7 and 35.1%, respectively than CC. GM, BM and GM-CLCC-N treatments provide higher yields than conventional practice. The average well color development value, Shannon index and McIntosh index were significantly higher by 26.6%, 86.9% and 29.2% in GM as compared to control treatment. So, from this study we can conclude that resource conservation practices like GM, GM-CLCC N and BM in combination with chemical fertilizers provide easily decomposable carbon source to support the microbial growth. Moreover, dominance of microbial activity in biomass amended treatments (GM, GM-CLCC N and BM) indicated that these treatments could supply good amount of labile C sources on real time basis for microbial growth that may protect the stable C fraction in soil, hence could support higher yield and soil organic carbon build-up in long run under rice-green gram soil.


Assuntos
Oryza , Solo , Solo/química , Carbono/análise , Biomarcadores Ambientais , Indicadores de Qualidade em Assistência à Saúde , Agricultura/métodos , Fertilizantes , Nitrogênio/análise
4.
J Environ Manage ; 303: 114151, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34844054

RESUMO

Mangroves play a key role in ecosystem balancing and climate change mitigation. It acts as a source and sink of methane (CH4), a major greenhouse gas responsible for climate change. Energy metabolic pathways of methane production (methanogenesis) and oxidation (methanotrophy) are directly driven by sulphur (S) and nitrogen (N) metabolism and salinity in coastal wetlands. To investigate, how mangrove-degradations, affect the source-sink behaviour of CH4; the pathways of CH4, S and N were studied through whole-genome metagenomic approach. Soil samples were collected from degraded and undisturbed mangrove systems in Sundarban, India. Structural and functional microbial diversities (KEGG pathways) of CH4, S and N metabolism were analysed and correlated with labile carbon pools and physico-chemical properties of soil. Overall, the acetoclastic pathway of methanogenesis was dominant. However, the relative proportion of conversion of CO2 to CH4 was more in degraded mangroves. Methane oxidation was higher in undisturbed mangroves and the serine pathway was dominant. After serine, the ribulose monophosphate pathway of CH4 oxidation was dominant in degraded mangrove, while the xylulose monophosphate pathway was dominant in undisturbed site as it is more tolerant to salinity and higher pH. The assimilatory pathway (AMP) of S-metabolism was dominant in both systems. But in AMP pathway, adenosine triphosphate sulfurylase enzyme reads were higher in degraded mangrove, while NADPH-sulfite reductase abundance was higher in undisturbed mangrove due to higher salinity, and pH. In N-metabolism, the denitrification pathway was predominant in degraded sites, whereas the dissimilatory nitrate reduction pathway was dominant in undisturbed mangroves. The relative ratios of sulphur reducing bacteria (SRB): methanogens were higher in degraded mangrove; however, methanotrophs:methanogens was higher in undisturbed mangrove indicated lower source and greater sink capacity of CH4 in the system. Microbial manipulation in mangrove-rhizosphere for regulating major energy metabolic pathways of methane could open-up a new window of climate change mitigation in coastal wetlands.


Assuntos
Ecossistema , Metano , Dióxido de Carbono/análise , Mudança Climática , Redes e Vias Metabólicas , Nitrogênio , Solo , Enxofre , Áreas Alagadas
5.
Environ Monit Assess ; 191(2): 98, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30675638

RESUMO

Land use and land cover (LULC) change have considerable influence on ecosystem services. Assessing change in ecosystem services due to LULC change at different spatial and temporal scales will help to identify suitable management practices for sustaining ecosystem productivity and maintaining the ecological balance. The objective of this study was to investigate variations in ecosystem services in response to LULC change over 27 years in four agro-climatic zones (ACZ) of eastern India using satellite imagery for the year 1989, 1996, 2005, 2011 (Landsat TM) and 2016 (Landsat 8 OLI). The satellite images were classified into six LULC classes, agriculture land, forest, waterbody, wasteland, built-up, and mining area. During the study period (1989 to 2016), forest cover reduced by 5.2%, 13.7%, and 3.6% in Sambalpur, Keonjhar, and Kandhamal districts of Odisha, respectively. In Balasore, agricultural land reduced by 17.2% due to its conversion to built-up land. The value of ecosystem services per unit area followed the order of waterbodies > agricultural land > forests. A different set of indicators, e.g., by explicitly including diversity, could change the rank between these land uses, so the temporal trends within a land use are more important than the absolute values. Total ecosystem services increased by US$ 1296.4 × 105 (50.74%), US$ 1100.7 × 105 (98.52%), US$ 1867 × 105 (61.64%), and US$ 1242.6 × 105 (46.13%) for Sambalpur, Balasore, Kandhamal, and Keonjhar, respectively.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais/métodos , Monitoramento Ambiental/métodos , Agricultura/métodos , Ecossistema , Florestas , Índia , Mineração , Imagens de Satélites/métodos
6.
Phys Rev Lett ; 121(24): 246402, 2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30608732

RESUMO

Characterizing the local internal environment surrounding solid-state spin defects is crucial to harnessing them as nanoscale sensors of external fields. This is especially germane to the case of defect ensembles which can exhibit a complex interplay between interactions, internal fields, and lattice strain. Working with the nitrogen-vacancy (NV) center in diamond, we demonstrate that local electric fields dominate the magnetic resonance behavior of NV ensembles at a low magnetic field. We introduce a simple microscopic model that quantitatively captures the observed spectra for samples with NV concentrations spanning more than two orders of magnitude. Motivated by this understanding, we propose and implement a novel method for the nanoscale localization of individual charges within the diamond lattice; our approach relies upon the fact that the charge induces a NV dark state which depends on the electric field orientation.

7.
Analyst ; 141(10): 2977-89, 2016 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-27048794

RESUMO

The present study concerns the enhancement of methanol selectivity of three dimensional (3D) nanoflowers (NFs) of ZnO by dispersing nickel oxide (NiO) and palladium oxide (PdO) nanoparticles on the surface of the nanoflowers to form localized hybrid nano-junctions. The nanoflowers were fabricated through a liquid phase deposition technique and the modification was achieved by addition of NiCl and PdCl2 solutions. In addition to the detailed structural (like X-ray diffraction (XRD), electron dispersive spectroscopy (EDS), X-ray mapping, XPS) and morphological characterization (by field emission scanning electron microscopy (FESEM)), the existence of different defect states (viz. oxygen vacancy) was also confirmed by photoluminescence (PL) spectroscopy. The sensing properties of the pristine and metal oxide nanoparticle (NiO/PdO)-ZnO NF hybrid sensor structures, towards different alcohol vapors (methanol, ethanol, 2-propanol) were investigated in the concentration range of 0.5-700 ppm at 100-350 °C. Methanol selectivity study against other interfering species, viz. ethanol, 2-propanol, acetone, benzene, xylene and toluene was also investigated. It was found that the PdO-ZnO NF hybrid system offered enhanced selectivity towards methanol at low temperature (150 °C) compared to the NiO-ZnO NF and pristine ZnO NF counterparts. The underlying mechanism for such improvement has been discussed with respective energy band diagram and preferential dissociation of target species on such 3D hybrid structures. The corresponding improvement in transient characteristics has also been co-related with the proposed model.

8.
Langmuir ; 31(4): 1385-92, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25557246

RESUMO

The properties of a material change remarkably as a result of the scaling dimensions. The Langmuir-Blodgett (LB) film deposition technique is known to offer precise control over the film thickness and the interparticle separation. To form a well-ordered LB film, it is essential to form a stable Langmuir film at the air-water interface. Here, we report our studies on ultrathin films of TiO2 nanoparticles at air-water and air-solid interfaces. The Langmuir film of TiO2 nanoparticles at the air-water interface was found to be very stable, and it exhibits loose-packing and close-packing phases. The LB films were transferred onto solid substrates for characterization and application. The surface morphology of the LB film was obtained by a field emission scanning electron microscope. The optical and electronic properties of the LB films of TiO2 nanoparticles were studied using UV-vis spectroscopy and current-voltage measurements, respectively. The LB film of TiO2 nanoparticles was employed for ethanol gas sensing, and the sensing performance was compared to that of bulk material. Because of the enormous gain in the surface to volume ratio and the increase in crystalline defect density in the ultrathin LB film of TiO2 nanoparticles, the LB film is found to be a potential functional layer for ethanol sensing as compared to the bulk material.

9.
Ecotoxicol Environ Saf ; 114: 257-62, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24836933

RESUMO

Fly ash (FA), a byproduct of coal combustion in thermal power plants, has been considered as a problematic solid waste and its safe disposal is a cause of concern. Several studies proposed that FA can be used as a soil additive; however its effect on microbial response, soil enzymatic activities and heavy metal accumulation in soil and grain of rice (cv. Naveen) to fly ash (FA) application was studied in a pot experiment during dry season 2011 in an Inceptisol. Fly ash was applied at a rate of zero per cent (FS), five per cent (FA5), ten per cent (FA10), twenty per cent (FA20), 40 per cent (FA40) and 100 per cent (FA100) on soil volume basis with nitrogen (N), phosphorus (P) and potassium (K) (40:20:20mg N:P:Kkg(-1) soil) with six replications. Heavy metals contents in soil and plant parts were analysed after harvest of crop. On the other hand, microbial population and soil enzymatic activities were analysed at panicle initiation stage (PI, 65 days after transplanting) of rice. There was no significant change in the concentration of zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), cadmium (Cd) and chromium (Cr) with application of fly ash up to FA10. However, at FA100 there was significant increase of all metals concentration in soil than other treatments. Microorganisms differed in their response to the rate of FA application. Population of both fungi and actinomycetes decreased with the application of fly ash, while aerobic heterotrophic bacterial population did not change significantly up to FA40. On the other hand, total microbial activity measured in terms of Fluorescein diacetate (FDA) assay, and denitrifiers showed an increased trend up to FA40. However, activities of both alkaline and acid phosphatase were decreased with the application of FA. Application of FA at lower levels (ten to twenty per cent on soil volume basis) in soil enhanced micronutrients content, microbial activities and crop yield.


Assuntos
Cinza de Carvão/farmacologia , Metais Pesados/análise , Oryza/química , Microbiologia do Solo , Solo/química , Actinobacteria/isolamento & purificação , Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Nitrogênio/metabolismo , Resíduos Sólidos
10.
Environ Monit Assess ; 187(5): 296, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25913623

RESUMO

Integrated rice-fish culture, an age-old farming system, is a technology which could produce rice and fish sustainably at a time by optimizing scarce resource use through complementary use of land and water. An understanding of microbial processes is important for the management of farming systems as soil microbes are the living part of soil organic matter and play critical roles in soil C and N cycling and ecosystem functioning of farming system. Rice-based integrated farming system model for small and marginal farmers was established in 2001 at Central Rice Research Institute, Cuttack, Odisha. The different enterprises of farming system were rice-fish, fish-fingerlings, fruits, vegetables, rice-fish refuge, and agroforestry. This study was conducted with the objective to assess the soil physicochemical properties, microbial population, carbon and nitrogen fractions, soil enzymatic activity, and productivity of different enterprises. The effect of enterprises induced significant changes in the chemical composition and organic matter which in turn influenced the activities of enzymes (urease, acid, and alkaline phosphatase) involved in the C, N, and P cycles. The different enterprises of long-term rice-based farming system caused significant variations in nutrient content of soil, which was higher in rice-fish refuge followed by rice-fish enterprise. Highest microbial populations and enzymatic properties were recorded in rice-fish refuge system because of waterlogging and reduced condition prolonged in this system leading to less decomposition of organic matter. The maximum alkaline phosphatase, urease, and FDA were observed in rice-fish enterprise. However, highest acid phosphatase and dehydrogenase activity were obtained in vegetable enterprise and fish-fingerlings enterprise, respectively.


Assuntos
Agricultura/métodos , Monitoramento Ambiental , Oryza/crescimento & desenvolvimento , Solo/química , Carbono/análise , Ecossistema , Nitrogênio , Microbiologia do Solo , Tempo , Urease , Verduras
11.
Environ Monit Assess ; 187(11): 679, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26450689

RESUMO

Thermal power stations apart from being source of energy supply are causing soil pollution leading to its degradation in fertility and contamination. Fine particle and trace element emissions from energy production in coal-fired thermal power plants are associated with significant adverse effects on human, animal, and soil health. Contamination of soil with cadmium, nickel, copper, lead, arsenic, chromium, and zinc can be a primary route of human exposure to these potentially toxic elements. The environmental evaluation of surrounding soil of thermal power plants in Odisha may serve a model study to get the insight into hazards they are causing. The study investigates the impact of fly ash-fugitive dust (FAFD) deposition from coal-fired thermal power plant emissions on soil properties including trace element concentration, pH, and soil enzymatic activities. Higher FAFD deposition was found in the close proximity of power plants, which led to high pH and greater accumulation of heavy metals. Among the three power plants, in the vicinity of NALCO, higher concentrations of soil organic carbon and nitrogen was observed whereas, higher phosphorus content was recorded in the proximity of NTPC. Multivariate statistical analysis of different variables and their association indicated that FAFD deposition and soil properties were influenced by the source of emissions and distance from source of emission. Pollution in soil profiles and high risk areas were detected and visualized using surface maps based on Kriging interpolation. The concentrations of chromium and arsenic were higher in the soil where FAFD deposition was more. Observance of relatively high concentration of heavy metals like cadmium, lead, nickel, and arsenic and a low concentration of enzymatic activity in proximity to the emission source indicated a possible link with anthropogenic emissions.


Assuntos
Monitoramento Ambiental , Metais Pesados/análise , Centrais Elétricas , Poluentes do Solo/análise , Solo/química , Carvão Mineral/análise , Cinza de Carvão/análise , Cinza de Carvão/química , Poeira/análise , Poluição Ambiental/análise , Humanos , Análise Multivariada , Poluentes do Solo/química
12.
World J Microbiol Biotechnol ; 30(2): 519-28, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23990071

RESUMO

Soil bacterial communities, which contain the highest level of prokaryotic diversity of any natural environment, are important for ecosystem functioning. A culture-independent metagenomic approach was employed in the present investigation to characterize the diversity of soil bacterial community composition in five geochemically and hydrologically different surface and subsurface soil habitats of Brahmaputra valley, Assam, North-East India, an Indo-Burma mega-biodiversity hotspot. The diversity of soil bacterial community was determined through sequence analysis of 16S-23S intergenic spacer regions (ISR). Polymerase chain reaction (PCR) universal primers, 1406F (5'-TGYACACACCGCCCGT-3') and 155r (5'-GGGTTBCATTCRG-3') were used for amplification of 16S-23S ribosomal DNA intergenic spacers of bacteria. Amplification resulted in an intense array of PCR products approximately ranging in size from 200 to 900 bp. Clear banding patterns were observed in analysed samples using the primer set in combination. A clear change in microbial ISR profile was observed on visual analysis of gel electrophoresis profiles. Fast alignment database searches of PCR amplicons of 16S-23S ISR sequence data revealed that the isolated sequences resembled five major phylogenetic groups of bacteria, namely α-, ß- and γ-subdivisions of Proteobacteria, Acidobacterium and Comamonadaceae.


Assuntos
Biota , Microbiologia do Solo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Índia , Filogenia , Análise de Sequência de DNA
13.
Environ Monit Assess ; 186(12): 8827-32, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25208521

RESUMO

The study was conducted to determine the optimum storage time for vermicompost without significant loss of nutrients; nitrogen (N), phosphorous (P), and potassium (K). Cattle manure, paddy straw, municipal solid wastes, and fly ash were used for vermicompost preparations. The dynamics of N, P, and K in the vermicomposts were studied during 180 days of incubation at 28-32 °C. In general, N concentration increased in the first 90-105 days of incubation and then gradually decreased until the 180th day while P and K concentrations steadily decreased over the length of the study, with the rate of loss leveling off after 150 days. The rate of nutrient loss was directly related to the initial level, decreasing the fastest for the nutrients with the highest initial concentrations. Optimum storage times were substrate and N dependent.


Assuntos
Carbono/análise , Nitrogênio/análise , Fósforo/análise , Potássio/análise , Poluentes do Solo/análise , Solo/química , Animais , Cinza de Carvão , Monitoramento Ambiental , Esterco/análise
14.
Environ Monit Assess ; 186(7): 4223-36, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24609455

RESUMO

In order to identify the viable option of tillage practices in rice-maize-cowpea cropping system that could cut down soil carbon dioxide (CO2) emission, sustain grain yield, and maintain better soil quality in tropical low land rice ecology soil respiration in terms of CO2 emission, labile carbon (C) pools, water-stable aggregate C fractions, and enzymatic activities were investigated in a sandy clay loam soil. Soil respiration is the major pathway of gaseous C efflux from terrestrial systems and acts as an important index of ecosystem functioning. The CO2-C emissions were quantified in between plants and rows throughout the year in rice-maize-cowpea cropping sequence both under conventional tillage (CT) and minimum tillage (MT) practices along with soil moisture and temperature. The CO2-C emissions, as a whole, were 24 % higher in between plants than in rows, and were in the range of 23.4-78.1, 37.1-128.1, and 28.6-101.2 mg m(-2) h(-1) under CT and 10.7-60.3, 17.3-99.1, and 17.2-79.1 mg m(-2) h(-1) under MT in rice, maize, and cowpea, respectively. The CO2-C emission was found highest under maize (44 %) followed by rice (33 %) and cowpea (23 %) irrespective of CT and MT practices. In CT system, the CO2-C emission increased significantly by 37.1 % with respect to MT on cumulative annual basis including fallow. The CO2-C emission per unit yield was at par in rice and cowpea signifying the beneficial effect of MT in maintaining soil quality and reduction of CO2 emission. The microbial biomass C (MBC), readily mineralizable C (RMC), water-soluble C (WSC), and permanganate-oxidizable C (PMOC) were 19.4, 20.4, 39.5, and 15.1 % higher under MT than CT. The C contents in soil aggregate fraction were significantly higher in MT than CT. Soil enzymatic activities like, dehydrogenase, fluorescein diacetate, and ß-glucosidase were significantly higher by 13.8, 15.4, and 27.4 % under MT compared to CT. The soil labile C pools, enzymatic activities, and heterotrophic microbial populations were in the order of maize > cowpea > rice, irrespective of the tillage treatments. Environmental sustainability point of view, minimum tillage practices in rice-maize-cowpea cropping system in tropical low land soil could be adopted to minimize CO2-C emission, sustain yield, and maintain soil health.


Assuntos
Agricultura/métodos , Carbono/análise , Microbiologia do Solo/normas , Solo/química , Biomassa , Ciclo do Carbono , Dióxido de Carbono/análise , Sequestro de Carbono , Ecossistema , Monitoramento Ambiental , Fabaceae/crescimento & desenvolvimento , Oryza/crescimento & desenvolvimento , Temperatura , Zea mays/crescimento & desenvolvimento
15.
Bull Environ Contam Toxicol ; 92(2): 160-4, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24362819

RESUMO

The microbial biomass carbon (MBC) and carbon mineralization of fly ash (FA) amended soil at (0 %, 1.25 %, 2.5 %, 5 %, 10 % and 20 % FA; v/v) was investigated under laboratory conditions for 120 days at 60 % soil water-holding capacity and 25 ± 1°C temperature. The results demonstrated that soil respiration and microbial activities were not suppressed up to 2.5 % FA amendment and these activities decreased significantly at 10 % and 20 % FA treatment with respect to control. Application of 10 % and 20 % FA treated soils showed a decreasing trend of soil MBC with time; and the decrease was significant throughout the period of incubation. The study concluded that application of FA up to 2.5 % can thus be safely used without affecting the soil biological activity and thereby improve nutrient cycling in agricultural soils.


Assuntos
Cinza de Carvão/toxicidade , Eliminação de Resíduos , Microbiologia do Solo , Poluentes do Solo/toxicidade , Agricultura , Biomassa , Carbono/análise , Carbono/química , Cinza de Carvão/química , Solo/química , Poluentes do Solo/química
16.
Bull Environ Contam Toxicol ; 93(1): 106-12, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24756333

RESUMO

An experiment was conducted to assess the effect of fly ash deposition without and with (0.25, 0.50, 1.0 and 1.5 g m(-2 )day(-1)) foliar dusting on the photosynthesis, stomatal conductance, transpiration, leaf temperature, albedo and productivity of rice. Dusting of 0.5 g m(-2 )day(-1) fly ash and above significantly reduced the photosynthesis, stomatal conductance, transpiration and albedo. Panicle initiation and flowering stages were more influenced by the fly ash deposition as compared to active tillering stage. At higher rates of fly ash deposition, all growth and yield parameters were significantly influenced due to increased heat load and reduced intercellular CO2 concentration. A significant reduction of 12.3, 15.7 and 20.2 % in grain yield was recorded over control when fly ash was dusted at 0.5, 1.0 and 1.5 g m(-2 )day(-1), respectively.


Assuntos
Cinza de Carvão/toxicidade , Poluentes Ambientais/toxicidade , Oryza/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Transpiração Vegetal/efeitos dos fármacos , Temperatura
17.
J Nanosci Nanotechnol ; 13(10): 6826-34, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24245150

RESUMO

Unmodified and Pd modified Zinc Oxide (ZnO) hexagonal nanorods, grown by Chemical Bath Deposition (CBD), is reported in this paper for efficient detection of acetone vapor. After details structural characterization (XRD, FESEM and AFM) the nanorod based sensors were tested in resistive mode for detection of acetone in the concentration range of - 190-3040 ppm. By Pd surface modification the optimum working temperature was brought down from 350 degrees C (unmodified) to 300 degrees C with appreciable improvement in response magnitude (90% to 99%) also. Strikingly, the recovery time, after Pd modification, became faster than the corresponding response time up to certain concentrations range (190-1530 ppm) and above this concentration (> or = 1530-3040 ppm) response time was found to be faster than recovery time which is similar to the case with unmodified nanorods (for entire concentration range). There are earlier reports on such faster recovery (compared to response), but no proper explanation was provided. In this paper we tried to explain this apparent anomaly of recovery characteristics through concentration dependent reaction rate variation following Arrhenius equations. Also a correlation between the parameters of the corresponding electrical equivalent circuit of the sensor has been established.

18.
J Postgrad Med ; 59(2): 121-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23793313

RESUMO

Hypotension during cesarean section under spinal anesthesia remains a frequent scenario in obstetric practice. A number of factors play a role in altering the incidence and severity of hypotension. Counteracting aortocaval compression does not significantly prevent hypotension in most singleton pregnancies. Intravenous crystalloid pre-hydration is not very efficient. Thus, the focus has changed toward co-hydration and use of colloids. Among vasopressors, phenylephrine is now established as a first line drug, although there is limited data in high-risk patients. Though ephedrine crosses the placenta more than phenylephrine and can possibly cause alterations in the fetal physiology, it has not been shown to affect the fetal Apgar or neurobehavioral scores.


Assuntos
Anestesia Obstétrica/métodos , Raquianestesia/efeitos adversos , Cesárea , Hipotensão/etiologia , Complicações Cardiovasculares na Gravidez/etiologia , Anestesia Obstétrica/efeitos adversos , Soluções Cristaloides , Gerenciamento Clínico , Efedrina/uso terapêutico , Feminino , Hidratação , Humanos , Hipotensão/terapia , Soluções Isotônicas , Gravidez , Complicações Cardiovasculares na Gravidez/prevenção & controle , Resultado da Gravidez , Vasoconstritores/uso terapêutico
19.
Environ Monit Assess ; 185(10): 8659-71, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23612768

RESUMO

Changes in the soil labile carbon fractions and soil biochemical properties to elevated carbon dioxide (CO2) and temperature reflect the changes in the functional capacity of soil ecosystems. The belowground root system and root-derived carbon products are the key factors for the rhizospheric carbon dynamics under elevated CO2 condition. However, the relationship between interactive effects of elevated CO2 and temperature on belowground soil carbon accrual is not very clear. To address this issue, a field experiment was laid out to study the changes of carbon allocation in tropical rice soil (Aeric Endoaquept) under elevated CO2 and elevated CO2 + elevated temperature conditions in open top chambers (OTCs). There were significant increase of root biomass by 39 and 44 % under elevated CO2 and elevated CO2 + temperature compared to ambient condition, respectively. A significant increase (55 %) of total organic carbon in the root exudates under elevated CO2 + temperature was noticed. Carbon dioxide enrichment associated with elevated temperature significantly increased soil labile carbon, microbial biomass carbon, and activities of carbon-transforming enzyme like ß-glucosidase. Highly significant correlations were noticed among the different soil enzymes and soil labile carbon fractions.


Assuntos
Dióxido de Carbono/análise , Sequestro de Carbono , Microbiologia do Solo , Solo/química , Temperatura , Carbono/análise , Ecossistema , Inundações , Oryza , Clima Tropical
20.
Magn Reson Imaging ; 103: 185-191, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37536637

RESUMO

PURPOSE: A combined resting state functional connectivity MRI (fcMRI) and diffusion tensor imaging (DTI) metric called structural and functional connectivity index (SFCI) was recently proposed for tracking disease status and progression in multiple sclerosis (MS). The metric combines fcMRI and transverse diffusivity (TD) along different functional pathways involved in principle symptomatic domains of MS. In a longitudinal study of patients with MS receiving the same MS therapy, initial worsening of transcallosal (TC) motor and frontoparietal (FP) cognitive networks, as measured by fcMRI and DTI over the first year was followed by stabilization in the second year of follow-up. In this study we have (i) probed relationships between individual and composite neurological measures of MS with SFCI and its individual components along TC motor and FP cognitive pathways and (ii) compared sensitivity of SFCI to treatment-induced longitudinal changes with each individual imaging measure. METHODS: Twenty five patients with MS (15 female, age 42 ± 8 y) participated in this study and were scanned at 3 T whole body MRI scanner with diffusion tensor imaging (DTI) and resting-state functional connectivity MRI (fcMRI) scan protocol at baseline and 6, 12, 18 and 24 months after starting fingolimod. fcMRI and TD along TC and FP pathways were combined to form structural and functional connectivity index (SFCI) at each time point. Correlations between individual/combined neurological measures and individual imaging components/SFCI at baseline and were evaluated and compared. In addition, efficacies of individual and combined imaging metrics in tracking network integrity were compared. RESULTS: Individual TD along the TC pathway was significantly inversely correlated with all individual/composite neurological scores. There were moderate correlations of TC and FP components of SFCI with most of the neurological scores, and the pathway-combined SFCI was significantly correlated with all neurological scores. Trend-level increases of both TC and FP fcMRI were observed during the second year of follow-up, both TC and FP TD increased significantly in the first year and then stabilized during the second year. A trend toward a decrease in combined imaging metrics along TC and FP were observed during the first year, followed by a trend toward an increase in these metrics during the second year, while a significant decrease in SFCI during the first year followed by a significant increase during the second year was observed. CONCLUSIONS: SFCI was more effective in tracking network integrity/disease progression than individual pathway-specific components, which supports its use as an imaging marker for MS disease status and progression.


Assuntos
Esclerose Múltipla , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Progressão da Doença , Encéfalo/diagnóstico por imagem
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