Revealing the Structural, Elastic, Electronic, and Optical Properties of K2ScCuCl6 and K2YCuCl6: An In-Depth Exploration Using Density Functional Theory.

The optoelectronic, structural, and elastic properties of K2ScCuCl6 and K2YCuCl6 double perovskite compounds were thoroughly investigated in this study using density functional theory. It is observed that both compounds exhibit exceptional structural and mechanical stability. The structural stability is assessed using Goldsmith's tolerance factor (tG), with values approaching unity indicating a reliable cubic perovskite structure. Phonon stability was ensured by the absence of negative energy formations and only real frequencies in the phonon calculations. Applying the finite displacement method also provided further evidence of the compounds' thermodynamic stability. The electronic properties analysis revealed that K2ScCuCl6 and K2YCuCl6 are narrow band gap semiconductors, with band gap values of 1.8 and 2.5 eV, respectively. This was confirmed by analyzing the density of states. Furthermore, the optical properties exhibited transparency at lower photon energies and significant absorption at higher energies. These exciting findings suggest that K2ScCuCl6 and K2YCuCl6 have promising applications in high-frequency UV devices.

Insight into the Structural, Electronic, Elastic, Optical, and Magnetic Properties of Cubic Fluoroperovskites ABF3 (A = Tl, B = Nb, V) Compounds: Probed by DFT.

This work displays the structural, electronic, elastic, optical, and magnetic properties in spin-polarized configurations for cubic fluoroperovskite ABF3 (A = Tl, B = Nb, V) compounds studied by density functional theory (DFT) by means of the Tran-Blaha-modified Becke-Johnson (TB-mBJ) approach. The ground state characteristics of these compounds, i.e., the lattice parameters a0, bulk modulus (B), and its pressure derivative B' are investigated. The structural properties depict that the selected compounds retain a cubic crystalline structure and have stable ground state energy. Electronic-band structures and DOS (density of states) in spin-polarized cases are studied which reports the semiconducting nature of both materials. The TDOS (total density of states) and PDOS (partial density of states) studies in both spin configurations show that the maximum contributions of states to the different bands is due to the B-site (p-states) atoms as well as F (p-states) atoms. Elastic properties including anisotropy factor (A), elastic constants, i.e., C11, C12, and C44, Poisson's ratio (υ), shear modulus and (G), Young's modulus (E) are computed. In terms of elastic properties, the higher (bulk modulus) "B" and ratio of "B/G" yield that these materials exhibit a ductile character. Magnetic properties indicate that both the compounds are ferromagnetic. In addition, investigations of the optical spectra including the real (ε1ω) and imaginary (ε2ω) component of the dielectric function, refractive index nω, optical reflectivity Rω, optical conductivity σω, absorption coefficient αω, energy loss function Lω, and electron extinction coefficient kω are carried out which shows the transparent nature of TlVF3 and TlNbF3. Based on the reported research work on these selected materials, their applications can be predicted in many modern electronic gadgets.

Insight into the exemplary structural, elastic, electronic and optical nature of GaBeCl3 and InBeCl3: a DFT study.

In the scheme of density functional theory (DFT), Structural, elastic, electronic, and optical properties calculations of GaBeCl3 and InBeCl3 are carried out using Tran-Blaha modified Becke-Johnson exchange potential approximation (TB-mBJ) installed in Wein2k software. Structurally the compounds of interest are found to be stable. Both compounds possess elastic stability, anisotropy, and ductility determined by the elastic studies. The electronic-band structure analysis shows the semiconductor nature of GaBeCl3 and InBeCl3 compounds with indirect band gaps of ∼3.08 eV for GaBeCl3 and ∼2.04 eV for InBeCl3 along with the symmetrical points from (X-Γ). The calculated total density of states (TDOS) and partial density of states (PDOS) of these compounds reveal that for the GaBeCl3 compound, the contribution of Ga (4p) and Cl (3p) orbital states in the valence, as well as the conduction band, is dominant. While for InBeCl3, the contribution of Cl (3p) states as well as In (5s) is large in the valence band and in that of Cl (3p-states) states in the conduction band. The type of chemical bonding is found to be ionic in both compounds. The optical properties i.e., the real (ε 1(ω)) and imaginary (ε 2(ω)) parts of dielectric function, refractive index n(ω), optical reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω), energy loss L(ω) and electron extinction coefficient k(ω) are also discussed in terms of optical spectra. It is reported that n(ω) and k(ω) exhibit the same characteristics as ε 1(ω) and ε 2(ω) respectively. Efficient application of these materials can be seen in semiconducting industries and many modern electronic devices.

Correction: Insight into the exemplary structural, elastic, electronic and optical nature of GaBeCl3 and InBeCl3: a DFT study.

[This corrects the article DOI: 10.1039/D2RA00943A.].

Functional Outcome After Decompressive Craniectomy in Patients with Dominant or Non-Dominant Malignant Middle Cerebral Infarcts.

BACKGROUND:  The use of decompressive craniectomy (DC) has been studied in the setting of different conditions, including traumatic brain injury, subarachnoid hemorrhage, and malignant middle cerebral artery (MCA) infarction. The rationale of this study is to determine the functional outcome after DC in patients with malignant MCA infarcts. METHODS:  A longitudinal cohort study was performed based on patients diagnosed with malignant MCA territory infarction admitted to the Neurosurgery Department of a tertiary care hospital in Islamabad, Pakistan between July 2015 and November 2016. All patients had a clinical diagnosis of stroke according to the World Health Organization (WHO) stroke criteria. RESULTS:  A total of 34 patients participated in this study, out of which 20/31 (64.5%) were males while 11/31 (35.5%) were females with a mean age of 51.61 ± 13.96 years. The mean time from diagnosis to surgery was 60.61 ± 49.83 hours. Out of 31 patients, 18 (58.1%) had a right middle cerebral artery infarct (RMCAI) and 13 (41.9%) had a left middle cerebral artery infarct (LCAI). Logistic regression was applied to assess the association between the type of MCA infarct with the National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), modified Barthel Index (mBI) scores, and upper and lower limb motor power. However, the logistic regression model was not statistically significant χ2 (4) = 3.896, p = 0.866. There was a statistically significant mild improvement of neurological scores and upper and lower motor power over a course of six months, but the overall functional outcome was poor with mBI < 60 and mRS > 4 (p < 0.001) with total mortality of 8.7%. CONCLUSION:  Decompressive craniectomy is a life-saving surgery that appears to benefit patients with malignant MCA infarcts of either the dominant or non-dominant cerebral hemisphere. Decompressive craniectomy results in mild improvements in neurological scores but still poor functional outcome after six months.

Ambulatory Treatment of Fast Breathing in Young Infants Aged <60 Days: A Double-Blind, Randomized, Placebo-Controlled Equivalence Trial in Low-Income Settlements of Karachi.

(See the Editorial Commentary by Jehan and Qazi on pages 190-1) BACKGROUND: Integrated Management of Childhood Illness recommends that young infants with isolated fast breathing be referred to a hospital for antibiotic treatment, which is often impractical in resource-limited settings. Additionally, antibiotics may be unnecessary for physiologic tachypnea in otherwise well newborns. We tested the hypothesis that ambulatory treatment with oral amoxicillin for 7 days was equivalent (similarity margin of 3%) to placebo in young infants with isolated fast breathing in primary care settings where hospital referral is often unfeasible. METHODS: This randomized equivalence trial was conducted in 4 primary health centers of Karachi, Pakistan. Infants presenting with isolated fast breathing and oxygen saturation ≥90% were randomly assigned to receive either oral amoxicillin or placebo twice daily for 7 days. Enrolled infants were followed on days 1-8, 11, and 14. The primary outcome was treatment failure by day 8, analyzed per protocol. The trial was stopped by the data safety monitoring board due to higher treatment failure rate and the occurrence of 2 deaths in the placebo arm in an interim analysis. RESULTS: Four hundred twenty-three infants fulfilled per protocol criteria in the amoxicillin arm and 426 in the placebo arm. Twelve infants (2.8%) had treatment failure in the amoxicillin arm and 25 (5.9%) in the placebo arm (risk difference, 3.1; P value .04). Two infants in the placebo arm died, whereas no deaths occurred in the amoxicillin arm. Other adverse outcomes, as well as the proportions of relapse, were evenly distributed across both study arms. CONCLUSIONS: This trial failed to show equivalence of placebo to amoxicillin in the management of isolated fast breathing without hypoxemia or other clinical signs of illness in term young infants. CLINICAL TRIALS REGISTRATION: NCT01533818.

Nurses in Supportive Housing are Associated With Decreased Health Care Utilization and Improved HIV Biomarkers in Formerly Homeless Adults.

A San Francisco study conducted in 2008 showed that the permanent supportive housing program, Direct Access to Housing, dramatically decreased the risk of death in people living with HIV. In our study, we compared the health care utilization patterns and HIV-related biological markers of formerly homeless adults with HIV before and during two types of permanent supportive housing: (a) housing with on-site nursing care for residents, and (b) housing without on-site nursing care. Using nearest-neighbor matching with propensity scoring, the difference in outcomes was calculated. In the matched analysis, adjusted for adherence to combination antiretroviral therapy, people housed at sites with nurses had 4.8 fewer emergency department visits per person (SE: 1.53, p < .01), and they had an increased mean CD4+ T cell count (101.14 cells per person [SE: 55.10, p < .05]) compared to those who lived at sites without nurses.

Ultrasound estimation of fetal weight: a formula for a Pakistani population.

AIM: To assess and validate the best model for fetal weight estimation in the Pakistani population. MATERIAL AND METHODS: The cohort included 178 women with singleton pregnancies at term (37-41 weeks) who had an ultrasound scan within 7 days of delivery. A proportionality formula was used to compensate for the fetal weight gain between the scan and the delivery. Data points from 119 pregnancies were used to derive the fetal weight formula, which was subsequently tested on the remaining 59 pregnancies. The best model for fetal weight estimation from ultrasound biometric parameters was selected. RESULTS: The selected model showed an interclass correlation coefficient with birthweight of 0.89. The systematic and random errors were -10 and 250 g, respectively. This validity assessment compared favorably with the performance of the more commonly used formulae when applied to our population. CONCLUSIONS: We describe a new model for fetal weight estimation in a Pakistani population which produces more valid and reliable estimates than currently used models derived from other populations.