580 research outputs found
(+/-)Methanodibenzodiazocine tethered [C-H](delta+) functional site: Study towards benzoin condensation and Baylis-Hillman reactions
New heterocyclic ring systems consisting of (+/-) methanodibenzodiazocine and imidazolium/ benzimidazolium salts were synthesized in very good yield. Subsequently, these halide salts were subjected to the anion exchange reaction with KPF6 to yield the corresponding azolium salts in excellent yield. The possible applications of these newly prepared salts were investigated in homogeneous catalysis. Remarkable changes in the catalytic activity were observed by varying the bulkiness of N-substituent at imidazole. Catalytic activity of these newly prepared salts was tested for the benzoin condensation reaction. Exclusive formation of benzoin products were observed in good yield. Similarly, the dimerization of cyclohexen-1-one to Baylis-Hillman type product, 2-(3-oxocyclohexyl)-2-cyclohexen-1-one was studied
An Interesting Cause of Mechanical Small Bowel Obstruction
Foreign body ingestion is a known cause of abdominal pain in pediatric population occurring between 6 months and 3 years of age (Wyllie Curr Opin Pediatr 18:563, 2006, Uyemura Am Fam Physician 72:287, 2005, Banerjee Indian J Pediatr 72:173, 2005). Most of the ingested foreign bodies pass spontaneously with 10-20 % requiring endoscopic retrieval, and \u3c 1 % of cases require a surgical intervention (Wyllie Curr Opin Pediatr 18:563, 2006, Uyemura Am Fam Physician 72:287, 2005, Shivakumar Indian J Pediatr 71:689, 2004). Presence of intestinal obstruction necessitates surgical intervention to extract the ingested foreign body. Initial abdominal plain radiograph should be obtained when foreign body ingestion is suspected, which differentiates a radiopaque from radiolucent foreign bodies. A computed tomography with 3D reconstruction (3D-CT) is recommended with radiolucent foreign bodies (Uyemura Am Fam Physician 72:287, 2005, Kazam Am J Emerg Med 23:897, 2005). After 24 h of expectant management, failure of spontaneous passage requires further intervention. Timely intervention to relieve the obstruction is pivotal to prevent undue complications. We present an interesting case of a boy who ingested a radiolucent foreign body diagnosed on 3D-CT, successfully treated with surgical extraction
SARAS 2: A Spectral Radiometer for probing Cosmic Dawn and the Epoch of Reionization through detection of the global 21 cm signal
The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization
(EoR), at redshifts , probes the nature of first sources of
radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the
signal is predicted to be extremely weak, of wide fractional bandwidth, and
lies in a frequency range that is dominated by Galactic and Extragalactic
foregrounds as well as Radio Frequency Interference, detection of the signal is
a daunting task. Critical to the experiment is the manner in which the sky
signal is represented through the instrument. It is of utmost importance to
design a system whose spectral bandpass and additive spurious can be well
calibrated and any calibration residual does not mimic the signal. SARAS is an
ongoing experiment that aims to detect the global 21 cm signal. Here we present
the design philosophy of the SARAS 2 system and discuss its performance and
limitations based on laboratory and field measurements. Laboratory tests with
the antenna replaced with a variety of terminations, including a network model
for the antenna impedance, show that the gain calibration and modeling of
internal additives leave no residuals with Fourier amplitudes exceeding 2~mK,
or residual Gaussians of 25 MHz width with amplitudes exceeding 2~mK. Thus,
even accounting for reflection and radiation efficiency losses in the antenna,
the SARAS~2 system is capable of detection of complex 21-cm profiles at the
level predicted by currently favoured models for thermal baryon evolution.Comment: 44 pages, 17 figures; comments and suggestions are welcom
A randomized, double-blinded trial comparing the effectiveness of tranexamic acid and epsilon-aminocaproic acid in reducing bleeding and transfusion in cardiac surgery
© 2019 Annals of Cardiac Anaesthesia. Objectives: To compare the effectiveness of epsilon aminocaproic acid (EACA) to tranexamic acid (TA) in reducing blood loss and transfusion requirements in patients undergone cardiac surgery under cardiopulmonary bypass. Design: Randomized, double blinded study. Outcome variables collected included; baseline demographic characteristics, type of surgery, amount of 24 hour chest tube drainage, amount of 24 hour blood products administered, 30 day mortality and morbidity and length of stay. We analyzed the data using parametric and non-parametric tests as appropriate. Setting: Single center tertiary-care university hospital setting. Participants: 114 patients who had undergone cardiac surgery under cardiopulmonary bypass. Interventions: Standard dose of intra-operative EACA or TA was compared in patients undergone cardiac surgery under cardiopulmonary bypass. Results: There was no statistically significant difference between groups when analyzing chest tube drainage. However, there was a significant difference in the administration of any transfusion (PRBC\u27s, FFP, platelets) intra-operatively to 24 hours postoperatively, with less transfusion in patients receiving EACA compared to TA (25% vs. 44.8%, respectively P = 0.027). Additionally, there was no significant difference in terms of adverse events during the one month follow up period. Conclusion: The findings of this study suggest that EACA and TA have similar effects on chest tube drainage but EACA is associated with fewer transfusions in CABG alone surgeries. Our results suggest that EACA can be used in a similar fashion to TA which may result in a cost and morbidity advantage
Studies on the proximity effect in Bi-based high-temperature superconductor/manganite heterostructures
The effect of proximity of the magnetism of the Pr-based manganite
(Pr0.6Sr0.4MnO3) on the superconductivity of Bi-based high-temperature
superconductor (Bi1.75Pb0.25Sr2Ca2Cu3O10+d) was studied based on the results
obtained from the magnetotransport and magnetization measurements. Decrease in
the values of the upper critical field (HC2(0)) and an increase in the width of
the superconducting transition (Delta TC) of Bi1.75Pb0.25Sr2Ca2Cu3O10+d were
observed in proximity with the manganite. The combined effect of magnetic
exchange interaction arising from the manganite, the leakage of Cooper-pairs
from the superconductor into the manganite, and the diffusion and transport of
spin-polarized electrons from the manganite into the superconductor were found
to modify the superconducting properties of Bi1.75Pb0.25Sr2Ca2Cu3O10+d. The
stacking sequence of the individual layers in these heterostructures was found
to dictate the ground state properties of the heterostructure. As a consequence
of the proximity effect, the colossal-magnetoresistance (CMR) ratio as high as
~ 99 % observed in the heterostructure makes the thin film heterostructures
promising candidates for potential technological applications.Comment: 29 pages, 14 figure
Fungal Endophytes to Combat Biotic and Abiotic Stresses for Climate-Smart and Sustainable Agriculture
The agricultural sustainability concept considers higher food production combating biotic and abiotic stresses, socio-economic well-being, and environmental conservation. On the contrary, global warming-led climatic changes have appalling consequences on agriculture, generating shifting rainfall patterns, high temperature, CO2, drought, etc., prompting abiotic stress conditions for plants. Such stresses abandon the plants to thrive, demoting food productivity and ultimately hampering food security. Though environmental issues are natural and cannot be regulated, plants can still be enabled to endure these abnormal abiotic conditions, reinforcing the stress resilience in an eco-friendly fashion by incorporating fungal endophytes. Endophytic fungi are a group of subtle, non-pathogenic microorganisms establishing a mutualistic association with diverse plant species. Their varied association with the host plant under dynamic environments boosts the endogenic tolerance mechanism of the host plant against various stresses via overall modulations of local and systemic mechanisms accompanied by higher antioxidants secretion, ample enough to scavenge Reactive Oxygen Species (ROS) hence, coping over-expression of defensive redox regulatory system of host plant as an aversion to stressed condition. They are also reported to ameliorate plants toward biotic stress mitigation and elevate phytohormone levels forging them worthy enough to be used as biocontrol agents and as biofertilizers against various pathogens, promoting crop improvement and soil improvement, respectively. This review summarizes the present-day conception of the endophytic fungi, their diversity in various crops, and the molecular mechanism behind abiotic and biotic resistance prompting climate-resilient aided sustainable agriculture.Peer reviewe
Maximally localized Wannier functions in LaMnO3 within PBE+U, hybrid functionals, and partially self-consistent GW: an efficient route to construct ab-initio tight-binding parameters for e_g perovskites
Using the newly developed VASP2WANNIER90 interface we have constructed
maximally localized Wannier functions (MLWFs) for the e_g states of the
prototypical Jahn-Teller magnetic perovskite LaMnO3 at different levels of
approximation for the exchange-correlation kernel. These include conventional
density functional theory (DFT) with and without additional on-site Hubbard U
term, hybrid-DFT, and partially self-consistent GW. By suitably mapping the
MLWFs onto an effective e_g tight-binding (TB) Hamiltonian we have computed a
complete set of TB parameters which should serve as guidance for more elaborate
treatments of correlation effects in effective Hamiltonian-based approaches.
The method-dependent changes of the calculated TB parameters and their
interplay with the electron-electron (el-el) interaction term are discussed and
interpreted. We discuss two alternative model parameterizations: one in which
the effects of the el-el interaction are implicitly incorporated in the
otherwise "noninteracting" TB parameters, and a second where we include an
explicit mean-field el-el interaction term in the TB Hamiltonian. Both models
yield a set of tabulated TB parameters which provide the band dispersion in
excellent agreement with the underlying ab initio and MLWF bands.Comment: 30 pages, 7 figure
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