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1.
Arch Microbiol ; 204(11): 669, 2022 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-36224280

RESUMEN

Existing pesticide formulation solvents generate volatile organic compounds (VOCs), are combustible, and are classed as hazardous air pollutants (HAPs), meaning they are detrimental to users and phytotoxic to crops. Green solvents are required in formulations due to regulations, health, and environmental concerns. In emulsifiable concentration (EC) formulations, the "green chemistry" movement has led to the use of less harmful solvents. After a detailed and comparative fungal growth inhibition assessment, the least harmful carrier solvent among four regularly used organic solvents [dimethyl sulfoxide (DMSO), dimethylformamide (DMF), aromatic hydrocarbon (C9), and methyl oleate] was chosen in this study. We employed methyl oleate (cis-9-Octadecenoic acid methyl ester) as a bio-based green reserver (60%) to create effective bioinspired EC formulations (30%) of Pongamia pinnata L extract utilising emulsifier blends (10 percent) based on the known toxicity order (DMF > DMSO > C9 > methyl oleate). EC1 outperformed the other thirteen formulations (EC1-EC13) in terms of emulsion stability, cold test, accelerated storage stability, flash point, and other metrics, proving its suitability for commercial production. Using four therapeutically appropriate concentrations of agricultural usage, in-vitro fungicidal effects against Alternaria solani and Phytophthora spp. were examined.A. solani (EC50 = 0.08 percent) showed the greatest growth suppression (87.4 percent) at the maximum dosage (1 percent), followed by Phytophthora sp. (71.1 percent) (EC50 = 0.49 percent). The study proved its utility in the production of environmentally acceptable green solvent-based herbal formulations as a long-term crop protection alternative to harmful chemical pesticides.


Asunto(s)
Contaminantes Atmosféricos , Plaguicidas , Compuestos Orgánicos Volátiles , Dimetilsulfóxido , Dimetilformamida , Emulsiones , Ésteres , Ácido Oléico , Extractos Vegetales/química , Solventes/química , Compuestos Orgánicos Volátiles/farmacología
2.
Phys Rev Lett ; 117(9): 097201, 2016 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-27610879

RESUMEN

Muon spin relaxation (µSR) experiments on single crystals of the structurally perfect triangular antiferromagnet YbMgGaO_{4} indicate the absence of both static long-range magnetic order and spin freezing down to 0.048 K in a zero field. Below 0.4 K, the µ^{+} spin relaxation rates, which are proportional to the dynamic correlation function of the Yb^{3+} spins, exhibit temperature-independent plateaus. All these µSR results unequivocally support the formation of a gapless U(1) quantum spin liquid ground state in the triangular antiferromagnet YbMgGaO_{4}.

3.
Phys Rev Lett ; 117(3): 037207, 2016 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-27472137

RESUMEN

The temperature-pressure phase diagram of the ferromagnet LaCrGe_{3} is determined for the first time from a combination of magnetization, muon-spin-rotation, and electrical resistivity measurements. The ferromagnetic phase is suppressed near 2.1 GPa, but quantum criticality is avoided by the appearance of a magnetic phase, likely modulated, AFM_{Q}. Our density functional theory total energy calculations suggest a near degeneracy of antiferromagnetic states with small magnetic wave vectors Q allowing for the potential of an ordering wave vector evolving from Q=0 to finite Q, as expected from the most recent theories on ferromagnetic quantum criticality. Our findings show that LaCrGe_{3} is a very simple example to study this scenario of avoided ferromagnetic quantum criticality and will inspire further study on this material and other itinerant ferromagnets.

4.
J Phys Condens Matter ; 36(34)2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38749470

RESUMEN

The disordered pyrochlore oxide Dy2Zr2O7shows the signatures of field-induced spin freezing with remnant zero-point spin-ice entropy at 5 kOe magnetic field. We have performed zero-field and longitudinal field Muon spin relaxation (µSR) studies on Dy2Zr2O7. Our zero field studies reveal the absence of both long-range ordering and spin freezing down to 62 mK. TheµSR relaxation rate exhibits a temperature-independent plateau below 4 K, indicating a dynamic ground state of fluctuating spins similar to the well-known spin ice system Dy2Ti2O7. The low-temperature spin fluctuations persist in the longitudinal field of 20 kOe as well and show unusual field dependence of the relaxation rate, which is uncommon for a spin-liquid system. Our results, combined with the previous studies do not show any evidence of spin ice or spin glass ground state, rather point to a disorder-induced dynamic magnetic ground state in the Dy2Zr2O7material.

5.
J Educ Health Promot ; 10: 382, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34912918

RESUMEN

BACKGROUND: It has been realized by senior researchers that interest in biostatistics is very poor among medical professionals. Knowledge of biostatistics plays an important role in medical research. Studies conducted about knowledge, attitude toward biostatistics by many researchers, but there were no works about factors in relation to it. Considering this gap, we tried to develop a new instrument. MATERIALS AND METHODS: Item generation and questionnaire formation were done using focus group discussion involving seven experts from different departments of medical colleges. Face validity and content validity and pilot testing were carried out step by step. In estimating reliability, internal consistency measured after collecting data from 66 study participants. Data were collected through self-administered paper-based questionnaire where response in each item was in five-point Likert scale. Cronbach's alpha for reliability analysis was used. RESULTS: In first stage, item generation through FGD, then face validity was assessed by senior faculties. Content validity was checked by Aiken's V index. In initial stages, with six items, Cronbach's alpha was 0.805. Scale mean and variance were 24.24 and 27.26. After final reliability testing, it became 0.866 with four items where scale mean and variance came to 15.85 and 16.38. CONCLUSION: All the six items were important factors. Reliability improved when knowledge in statistics in higher secondary level and biostatistics classes in PG course were eliminated as factors. More qualitative research is needed for better understanding of this concept.

6.
Artículo en Inglés | MEDLINE | ID: mdl-33925610

RESUMEN

Rice-based diet faces an important public health concern due to arsenic (As) accumulation in rice grain, which is toxic to humans. Rice crops are prone to assimilate As due to continuously flooded cultivation. In this study, the objective was to determine how water regimes (flooded and aerobic) in rice cultivation impact total As and inorganic As speciation in rice on the basis of a field-scale trial in the post-monsoon season. Iron and silicon with NPK/organic manure were amended in each regime. We hypothesised that aerobic practice receiving amendments would reduce As uptake in rice grain with a subsequent decrease in accumulation of inorganic As species relative to flooded conditions (control). Continuously flooded conditions enhanced soil As availability by 32% compared to aerobic conditions. Under aerobic conditions, total As concentrations in rice decreased by 62% compared to flooded conditions. Speciation analyses revealed that aerobic conditions significantly reduced (p < 0.05) arsenite (68%) and arsenate (61%) accumulation in rice grains. Iron and silicon exhibited significant impact on reducing arsenate and arsenite uptake in rice, respectively. The study indicates that aerobic rice cultivation with minimum use of irrigation water can lead to lower risk of inorganic As exposure to rice relative to flooded practice.


Asunto(s)
Arsénico , Oryza , Contaminantes del Suelo , Arsénico/análisis , Arsénico/toxicidad , Humanos , Suelo , Contaminantes del Suelo/análisis , Agua
7.
Heliyon ; 7(3): e06557, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33855235

RESUMEN

Pongamia pinnata (L.) seed oil is effective for its insecticidal and larvicidal activities. However, its low aqueous solubility, high photosensitivity, and high volatility restrict its application for the control of agricultural pests. Encapsulation can be an effective technique to overcome such hindrances. Therefore, P. pinnata oil (PO) was extracted from its seeds and analyzed for karanjin content (3.18%) by GC-MS/MS as the marker compound. Micro-encapsulation (MC) of PO was prepared by interfacial polymerization between isocyanates and polyamine and tested for insecticidal and larvicidal activities. Bioassay of the developed formulations was tested in-vitro against 2nd instar larvae of Bombyx mori (Bivoltine hybrid) and in-vivo insecticidal bio-efficacy was tested against aubergine aphid (Aphis gossypii G.) and whitefly (Bemisia tabaci G.). Various properties of micro-capsules viz., stability, size, oil content and release kinetics were examined. Average diameter of capsules (1 µm) with Zeta potential (-16 mV) was indicated by the Dynamic Light Scattering (DLS) instrument. Existence of PO in the microcapsules was confirmed by an optical microscopic study. Spectroscopic analysis revealed 87.4% of PO was encapsulated in polyurea shell. The shelf-life (T 10 ), half-life (T 50 ), and expiry-life (T 90 ) of polyurea coated capsules were 11.4, 75.3 and 250.0 h, respectively. Polyurea coated PO capsule formulation showed evidence of in-vitro toxicity against 2nd instar larvae of B. mori (LC 50 = 1.1%; LC 90 = 5.9%). The PO formulation also exhibited 67.0-71.8% and 62.4-74.8% control of aphid and whitefly population in aubergine at 4.0% dose following 7-14 days after application. The study unveiled its significance in developing controlled release herbal formulations of P. pinnata as an alternative to harmful conventional synthetic insecticides for crop protection.

8.
ISA Trans ; 97: 384-400, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31402045

RESUMEN

In this paper modelling and comparative dynamic analysis of a field oriented controlled permanent magnet synchronous motor (PMSM) torque drive employing a hysteresis current controller and a PWM (Pulse Width Modulation) operated current controller is presented. To illustrate the proposed concept in this torque controlled drive, torque and mutual flux linkages are applied as external inputs and speed of the machine is kept fixed. Moreover the magnitude of torque angle as well as stator current reference is controlled through the proposed machine dynamics. In fact a computation based on demagnetization of direct axis current to achieve the flux weakening in this proposed drive for current compensation is also introduced. To achieve the faster computation and accuracy Euler's integration technique is used to solve the proposed complex dynamics of the permanent magnet synchronous machine. In a hysteresis current, controllers with a large hysteresis band current ripple and the torque pulsations are prominent at higher carrier frequency of the inverter. Additionally, a relationship with the magnitude of torque pulsations, PWM carrier frequency and the hysteresis window size is also achieved through various case-studies. Furthermore, the presence of current ripple and the pulsations generate some noise as well as vibration in a typical electric propulsion system. Afterwards a PWM current controller with identical operating conditions is proposed for such reduction of torque pulsation as well as ripples in the current waveform. Finally various feasible results are presented through MATLAB simulation and necessary hardware implementation to justify the comparative assessment of the proposed controllers for dynamic performance analysis in energy-efficient electric vehicles.

9.
J Phys Condens Matter ; 32(21): 215402, 2020 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-32032009

RESUMEN

Topological band dispersions other than the standard Dirac or Weyl fermions have garnered the increasing interest in materials science. Among them, the cubic Dirac fermions were recently proposed in the family of quasi-one-dimensional (q-1D) conductors A2Mo6X6 (A = Na, K, In, Tl; X = S, Se, Te), where the band crossing is characterized by a linear dispersion in one k-space direction but the cubic dispersion in the plane perpendicular to it. It is not yet clear, however, how the external perturbations can alter these nontrivial carriers and ultimately induce a new distinct quantum phase. Here we study the evolution of Dirac fermions, in particular the cubic Dirac crossing, under external pressure in the representative q-1D Tl2Mo6Se6 via the first-principles calculations. Specifically, it is found that the topological properties, including the bulk Dirac crossings and the topological surface states, change progressively under pressure up to 50 GPa where it undergoes a structural transition from the hexagonal phase to body-centered tetragonal phase. Above 50 GPa, the system is more likely to be topologically trivial. Further, we also investigate its phonon spectra, which reveals a gradual depletion of the negative phonon modes with pressure, consistent with the more three-dimensional Fermi surface in the high-pressure phase. Our work may provide a useful guideline for further experimental search and the band engineering of the topologically nontrivial fermions in this intriguing state of matter.

10.
Sci Rep ; 10(1): 12957, 2020 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-32737391

RESUMEN

Transition-metal dichalcogenides (TMDs) offer an ideal platform to experimentally realize Dirac fermions. However, typically these exotic quasiparticles are located far away from the Fermi level, limiting the contribution of Dirac-like carriers to the transport properties. Here we show that NiTe2 hosts both bulk Type-II Dirac points and topological surface states. The underlying mechanism is shared with other TMDs and based on the generic topological character of the Te p-orbital manifold. However, unique to NiTe2, a significant contribution of Ni d orbital states shifts the energy of the Type-II Dirac point close to the Fermi level. In addition, one of the topological surface states intersects the Fermi energy and exhibits a remarkably large spin splitting of 120 meV. Our results establish NiTe2 as an exciting candidate for next-generation spintronics devices.

11.
J Phys Chem Lett ; 11(18): 7782-7789, 2020 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-32856921

RESUMEN

The past decade has witnessed the burgeoning discovery of a variety of topological states of matter with distinct nontrivial band topologies. Thus far, most materials that have been studied possess two-dimensional or three-dimensional electronic structures, with only a few exceptions that host quasi-one-dimensional (quasi-1D) topological electronic properties. Here we present clear-cut evidence for Dirac Fermions in the quasi-1D telluride TaNiTe5. We show that its transport behaviors are highly anisotropic, and we observe nontrivial Berry phases via quantum oscillation measurements. The nontrivial band topology is further corroborated by first-principles calculations. Our results may help to guide the future quest for topological states in this new family of quasi-1D ternary chalcogenides.

12.
Sci Adv ; 4(1): eaao5235, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29326982

RESUMEN

The origin of the pseudogap region below a temperature T* is at the heart of the mysteries of cuprate high-temperature superconductors. Unusual properties of the pseudogap phase, such as broken time-reversal and inversion symmetry are observed in several symmetry-sensitive experiments: polarized neutron diffraction, optical birefringence, dichroic angle-resolved photoemission spectroscopy, second harmonic generation, and polar Kerr effect. These properties suggest that the pseudogap region is a genuine thermodynamic phase and are predicted by theories invoking ordered loop currents or other forms of intra-unit-cell (IUC) magnetic order. However, muon spin rotation (µSR) and nuclear magnetic resonance (NMR) experiments do not see the static local fields expected for magnetic order, leaving room for skepticism. The magnetic resonance probes have much longer time scales, however, over which local fields could be averaged by fluctuations. The observable effect of the fluctuations in magnetic resonance is then dynamic relaxation. We have measured dynamic muon spin relaxation rates in single crystals of YBa2Cu3O y (6.72 < y < 6.95) and have discovered "slow" fluctuating magnetic fields with magnitudes and fluctuation rates of the expected orders of magnitude that set in consistently at temperatures Tmag ≈ T*. The absence of any static field (to which µSR would be linearly sensitive) is consistent with the finite correlation length from neutron diffraction. Equally important, these fluctuations exhibit the critical slowing down at Tmag expected near a time-reversal symmetry breaking transition. Our results explain the absence of static magnetism and provide support for the existence of IUC magnetic order in the pseudogap phase.

13.
Sci Rep ; 5: 13788, 2015 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-26346548

RESUMEN

The recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p ≃ 3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p ≃ 7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc ≃ 1.2 K which decreases upon increasing the pressure. In the intermediate pressure region (3.5 < or ~ p < or ~ 7 kbar) the superconducting and the magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with Tc(3.2) as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs.

14.
Anesth Essays Res ; 7(2): 228-31, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-25885838

RESUMEN

INTRODUCTION: Carbon dioxide pneumoperitoneum (PP) for laparoscopic surgery increases arterial pressure, heart rate, and systemic vascular resistance. In this randomized, double blind, prospective clinical study; we investigated the efficacy of magnesium sulfate to prevent adverse hemodynamic response associated with PP in patients undergoing laparoscopic cholecystectomy. MATERIALS AND METHODS: Sixty patients, of either sex (18-65 years of age), undergoing elective laparoscopic cholecystectomy were randomly allocated in one of the two groups containing 30 patients each. Group M received magnesium sulfate 30 mg/kg intravenously as a bolus before PP. Group C received same volume of 0.9% saline. RESULTS: Mean arterial pressure and heart rate were significantly less throughout the period of pneumoperitoneum in patients of group M. Intravenous labetalol was required in 40% (12 out of 30) of the patients in group C to control intraoperative hypertension and it was clinically significant in comparison to group M. CONCLUSION: Magnesium sulfate administered before PP attenuates adverse hemodynamic response and provides hemodynamic stability during PP created for laparoscopic surgery.

15.
Bull Environ Contam Toxicol ; 79(5): 566-9, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17924045

RESUMEN

Napropamide is an amide group of herbicide, used as pre-emergence herbicide controlling in broad leaved weeds of tea, ground nut, citrus, etc. Napropamide 45 SC (Devrinol) was applied on tea bushes twice @ 1.125 and 2.250 g a.i./ha along with untreated control. After following the standard extraction process, the residue of napropamide in made tea and soil cropped with tea was analyzed by HPLC. Napropamide was rapidly dissipated in soil following the first-order kinetics with half-lives in the range of 12.54-27.87 days. The residue in made tea found to be below detectable limit on 7th day samples.


Asunto(s)
Camellia sinensis/química , Herbicidas/química , Naftalenos/química , Suelo/análisis , Té/química , Clima , India , Estructura Molecular , Contaminantes del Suelo , Factores de Tiempo
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