400 research outputs found
Bandgap engineering of Cd1-xSrxO
Structural, electronic and optical properties of Cd1-xSrxO (0 \leq x \leq 1)
are calculated for the first time using density functional theory. Our results
show that these properties are strongly dependent on x. The bond between Cd and
O is partially covalent and the covalent nature of the bond decreases as the
concentration of Sr increases from 0 to 100%. It is found that Cd1-xSrxO is an
indirect bandgap compound for the entire range of x and the bandgap of the
alloy increases from 0.85 to 6.00 eV with the increase in Sr concentration.
Frequency dependent dielectric functions {\epsilon}1({\omega}),
{\epsilon}2({\omega}), refractive index n({\omega}) and absorption coefficient
{\alpha}({\omega}) are also calculated and discussed in details. The peak value
of refractive indices shifts to higher energy regions with the increase in Sr.
The striking feature of these alloys is that Cd0.5Sr0.5O is an anisotropic
material. The larger value of the extraordinary refractive index confirms that
the material is positive birefringence crystal. The present comprehensive
theoretical study of the optoelectronic properties of the material predicts
that it can be effectively used in optoelectronic applications in the wide
range of spectrum; IR, visible and UV
Primary thermometry triad at 6 mK in mesoscopic circuits
Quantum physics emerge and develop as temperature is reduced. Although
mesoscopic electrical circuits constitute an outstanding platform to explore
quantum behavior, the challenge in cooling the electrons impedes their
potential. The strong coupling of such micrometer-scale devices with the
measurement lines, combined with the weak coupling to the substrate, makes them
extremely difficult to thermalize below 10 mK and imposes in-situ thermometers.
Here we demonstrate electronic quantum transport at 6 mK in micrometer-scale
mesoscopic circuits. The thermometry methods are established by the comparison
of three in-situ primary thermometers, each involving a different underlying
physics. The employed combination of quantum shot noise, quantum back-action of
a resistive circuit and conductance oscillations of a single-electron
transistor covers a remarkably broad spectrum of mesoscopic phenomena. The
experiment, performed in vacuum using a standard cryogen-free dilution
refrigerator, paves the way toward the sub-millikelvin range with additional
thermalization and refrigeration techniques.Comment: Article and Supplementar
Risk Factors of Diarrhoea in Malnourished Children Under Age of 5 Years
Background: Acute infectious enteritis remains one of the commonest causes of death among infants and children in developing countries. Acute enteritis is defined as a loss of stool consistency with pasty or liquid stools, and/or an increase in stool frequency to more than three stools in 24 hours with or without fever or vomiting. Human survival depends on the secretion and reabsorption of fluid and electrolytes in the intestinal tract. The objective of the study is to evaluate the risk factors of diarrhoea in children under age of 5 years.
Methodology: It was an observational study. Study was completed in about six months. Non-probability purposive sampling technique was used. In this study, 270 samples were taken from Diarrheal ward of The Children Hospital Lahore, Pakistan.
Results: In this study, out of 270 patients, 58.52% were males and 41.48% were females. 90.37% patients were vaccinated. 54.81% had weaning history. 91.85% patients had feeding history. 29.26% had blood in stool. 96.67% patients were dehydrated. 95.56% patients had loose watery diarrhoea. 62.96% patients used boiled water. 58.52% patients consumed less than half litre of water, 30.00% patients consumed 1 litre of water and 11.48% patients consumed > 1 litre of water. 49.18% patients had proper hygiene. 38.15% mothers of patients were well educated. 40.37% patients had model household condition. 57.41% patients lived in rural area and 42.59% patients lived in urban area.
Conclusion: The variation in the level of diarrheal morbidity was well explained by maternal education, income, personal hygiene, refuse disposal system and the effect of health extension programme
Two-channel Kondo effect and renormalization flow with macroscopic quantum charge states
Many-body correlations and macroscopic quantum behaviors are fascinating
condensed matter problems. A powerful test-bed for the many-body concepts and
methods is the Kondo model which entails the coupling of a quantum impurity to
a continuum of states. It is central in highly correlated systems and can be
explored with tunable nanostructures. Although Kondo physics is usually
associated with the hybridization of itinerant electrons with microscopic
magnetic moments, theory predicts that it can arise whenever degenerate quantum
states are coupled to a continuum. Here we demonstrate the previously elusive
`charge' Kondo effect in a hybrid metal-semiconductor implementation of a
single-electron transistor, with a quantum pseudospin-1/2 constituted by two
degenerate macroscopic charge states of a metallic island. In contrast to other
Kondo nanostructures, each conduction channel connecting the island to an
electrode constitutes a distinct and fully tunable Kondo channel, thereby
providing an unprecedented access to the two-channel Kondo effect and a clear
path to multi-channel Kondo physics. Using a weakly coupled probe, we reveal
the renormalization flow, as temperature is reduced, of two Kondo channels
competing to screen the charge pseudospin. This provides a direct view of how
the predicted quantum phase transition develops across the symmetric quantum
critical point. Detuning the pseudospin away from degeneracy, we demonstrate,
on a fully characterized device, quantitative agreement with the predictions
for the finite-temperature crossover from quantum criticality.Comment: Letter (5 pages, 4 figures) and Methods (10 pages, 6 figures
Prevalence of Vitamin B12 deficiency in patients of type 2 diabetes mellitus on metformin: A case control study from Pakistan
Introduction: Diabetes Mellitus is the most common endocrine disorder and metformin is the most commonly prescribed oral hypoglycemicagent. Metformin is well known to cause viamin B12 deficiency due to effect on calcium-dependent membrane action in the terminal ileum leading to malabsorption of vitamin B12. The purpose of this study is to determine prevalence and associations of Vitamin B12 deficiency in patients of type 2 diabetes mellitus treated with metformin. Methods: This case control study was carried out in department of medicine, Combined Military Hospital, Kharian from 1st Jan 2012 to 30 december 2012.We enrolled 114 outdoor patients of type 2 diabetes mellitus currently on metformin for atleast 12 months, by consecutive sampling, and 105 age and sex matched patients taken as control. Patients with vitamin B12 levels of less than 150 pg/ml were said to be B12 deficient. The results were analyzed on SPSS version 16.Results: Serum B12 levels were low in 35 patients (31%) on metformin as compared to only 9 patients (8.6%) among controls,(p value 0.002). Mean B12 levels were significantly low in metformin group 311 pg/ml (±194.4), p value 0.03. Dose of metformin had inverse correlation with B12 levels and the difference was statistically significant with pvalue < 0.001.Conclusion: Our study demonstrated significantly high prevalence of vitamin B12 deficiency in patients treated with metformin with significant effect of dose and duration of metformin use on B12 levels. Physicians must recognize this important fact and screen diabetics on metformin therapy for underlying B12 deficiency
Circuit Quantum Simulation of a Tomonaga-Luttinger Liquid with an Impurity
The Tomonaga-Luttinger liquid (TLL) concept is believed to generically
describe the strongly-correlated physics of one-dimensional systems at low
temperatures. A hallmark signature in 1D conductors is the quantum phase
transition between metallic and insulating states induced by a single impurity.
However, this transition impedes experimental explorations of real-world TLLs.
Furthermore, its theoretical treatment, explaining the universal energy
rescaling of the conductance at low temperatures, has so far been achieved
exactly only for specific interaction strengths. Quantum simulation can provide
a powerful workaround. Here, a hybrid metal-semiconductor dissipative quantum
circuit is shown to implement the analogue of a TLL of adjustable electronic
interactions comprising a single, fully tunable scattering impurity.
Measurements reveal the renormalization group `beta-function' for the
conductance that completely determines the TLL universal crossover to an
insulating state upon cooling. Moreover, the characteristic scaling energy
locating at a given temperature the position within this conductance
renormalization flow is established over nine decades versus circuit
parameters, and the out-of-equilibrium regime is explored. With the quantum
simulator quality demonstrated from the precise parameter-free validation of
existing and novel TLL predictions, quantum simulation is achieved in a strong
sense, by elucidating interaction regimes which resist theoretical solutions.Comment: To be published in Phys. Rev.
Population‐based cohort study of outcomes following cholecystectomy for benign gallbladder diseases
Background The aim was to describe the management of benign gallbladder disease and identify characteristics associated with all‐cause 30‐day readmissions and complications in a prospective population‐based cohort. Methods Data were collected on consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing all‐cause 30‐day readmissions and complications were analysed by means of multilevel, multivariable logistic regression modelling using a two‐level hierarchical structure with patients (level 1) nested within hospitals (level 2). Results Data were collected on 8909 patients undergoing cholecystectomy from 167 hospitals. Some 1451 cholecystectomies (16·3 per cent) were performed as an emergency, 4165 (46·8 per cent) as elective operations, and 3293 patients (37·0 per cent) had had at least one previous emergency admission, but had surgery on a delayed basis. The readmission and complication rates at 30 days were 7·1 per cent (633 of 8909) and 10·8 per cent (962 of 8909) respectively. Both readmissions and complications were independently associated with increasing ASA fitness grade, duration of surgery, and increasing numbers of emergency admissions with gallbladder disease before cholecystectomy. No identifiable hospital characteristics were linked to readmissions and complications. Conclusion Readmissions and complications following cholecystectomy are common and associated with patient and disease characteristics
Meroterpenoids: A Comprehensive Update Insight on Structural Diversity and Biology.
Funder: This research was funded by the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast-track Research Funding ProgramMeroterpenoids are secondary metabolites formed due to mixed biosynthetic pathways which are produced in part from a terpenoid co-substrate. These mixed biosynthetically hybrid compounds are widely produced by bacteria, algae, plants, and animals. Notably amazing chemical diversity is generated among meroterpenoids via a combination of terpenoid scaffolds with polyketides, alkaloids, phenols, and amino acids. This review deals with the isolation, chemical diversity, and biological effects of 452 new meroterpenoids reported from natural sources from January 2016 to December 2020. Most of the meroterpenoids possess antimicrobial, cytotoxic, antioxidant, anti-inflammatory, antiviral, enzyme inhibitory, and immunosupressive effects
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