Climate-invariant machine learning.

Projecting climate change is a generalization problem: We extrapolate the recent past using physical models across past, present, and future climates. Current climate models require representations of processes that occur at scales smaller than model grid size, which have been the main source of model projection uncertainty. Recent machine learning (ML) algorithms hold promise to improve such process representations but tend to extrapolate poorly to climate regimes that they were not trained on. To get the best of the physical and statistical worlds, we propose a framework, termed "climate-invariant" ML, incorporating knowledge of climate processes into ML algorithms, and show that it can maintain high offline accuracy across a wide range of climate conditions and configurations in three distinct atmospheric models. Our results suggest that explicitly incorporating physical knowledge into data-driven models of Earth system processes can improve their consistency, data efficiency, and generalizability across climate regimes.

Model spread in tropical low cloud feedback tied to overturning circulation response to warming.

Among models participating in the Coupled Model Intercomparison Project phase 6 (CMIP6), here we show that the magnitude of the tropical low cloud feedback, which contributes considerably to uncertainty in estimates of climate sensitivity, is intimately linked to tropical deep convection and its effects on the tropical atmospheric overturning circulation. First, a reduction in tropical ascent area and an increased frequency of heavy precipitation result in high cloud reduction and upper-tropospheric drying, which increases longwave cooling and reduces subsidence weakening, favoring low cloud reduction (Radiation-Subsidence Pathway). Second, increased longwave cooling decreases tropospheric stability, which also reduces subsidence weakening and low cloudiness (Stability-Subsidence Pathway). In summary, greater high cloud reduction and upper-tropospheric drying (negative longwave feedback) lead to a more positive cloud feedback among CMIP6 models by contributing to a greater reduction in low cloudiness (positive shortwave feedback). Varying strengths of the two pathways contribute considerably to the intermodel spread in climate sensitivity.

Coordination of Quantum Dots in a Polar Solvent by Small-Molecule Imidazole Ligands.

Colloidal quantum dots (QDs) are attractive fluorophores for bioimaging and biomedical applications because of their favorable and tunable optoelectronic properties. In this study, the native hydrophobic ligand environment of oleate-capped sphalerite CdSe/ZnS core/shell QDs was quantitatively exchanged with a set of imidazole-bearing small-molecule ligands. Inductively coupled plasma-optical emission spectroscopy and 1H NMR were used to identify and quantify three different ligand exchange processes: Z-type dissociation of the Zn(oleate)2, L-type association of the imidazole, and X-type anionic exchange of oleate with Cl-, all of which contributed to the overall ligand exchange.

Structure-property investigations in urea tethered iodinated triphenylamines.

Herein, we report structural, computational, and conductivity studies on urea-directed self-assembled iodinated triphenylamine (TPA) derivatives. Despite numerous reports of conductive TPAs, the challenges of correlating their solid-state assembly with charge transport properties hinder the efficient design of new materials. In this work, we compare the assembled structures of a methylene urea bridged dimer of di-iodo TPA (1) and the corresponding methylene urea di-iodo TPA monomer (2) with a di-iodo mono aldehyde (3) control. These modifications lead to needle shaped crystals for 1 and 2 that are organized by urea hydrogen bonding, π⋯π stacking, I⋯I, and I⋯π interactions as determined by SC-XRD, Hirshfeld surface analysis, and X-ray photoelectron spectroscopy (XPS). The long needle shaped crystals were robust enough to measure the conductivity by two contact probe methods with 2 exhibiting higher conductivity values (∼6 × 10-7 S cm-1) compared to 1 (1.6 × 10-8 S cm-1). Upon UV-irradiation, 1 formed low quantities of persistent radicals with the simple methylurea 2 displaying less radical formation. The electronic properties of 1 were further investigated using valence band XPS, which revealed a significant shift in the valence band upon UV irradiation (0.5-1.9 eV), indicating the potential of these materials as dopant free p-type hole transporters. The electronic structure calculations suggest that the close packing of TPA promotes their electronic coupling and allows effective charge carrier transport. Our results show that ionic additives significantly improve the conductivity up to ∼2.0 × 10-6 S cm-1 in thin films, enabling their implementation in functional devices such as perovskite or solid-state dye sensitized solar cells.

Choice of Antimicrobials in Surgical Prophylaxis - Overuse and Surgical Site Infection Outcomes from a Tertiary-Level Care Hospital.

Background: This study was aimed to describe the choice of Surgical Antimicrobial Prophylaxis at a tertiary-level care hospital in United Arab Emirates. It also associated the choice between two leading antimicrobials for the SAP to the site of surgery. Methods: A descriptive drug use evaluation was performed retrospectively to study choices of antimicrobials in surgical antibiotic prophylaxis. An analytical cross-sectional study design was used to develop a hypothesis regarding the choice of ceftriaxone. Data were collected from the medical records of Hospital from July 2020 to December 2020. Results were presented in numbers and percentages. Results: SAP data were collected from 199 patients, of which 159 were clean or clean-contaminated. Dirty surgeries (18) needed a higher level of antimicrobials as there were infections to be treated. For other surgeries with no infection, overuse of antimicrobials was found regarding the choice of antimicrobials. Surgical antibiotic Prophylaxis was administered within the recommended time prior to surgeries. Ceftriaxone was preferred over cefuroxime in all types of surgeries based on the timing of Surgical Antibiotic Prophylaxis, wound classification, and the surgical site. A statistically significant association for choice of ceftriaxone over cefuroxime was found regarding surgical sites (p-value <0.05). About 99% of the patients were prescribed discharge antimicrobials when 158 (80%) surgeries were clean or clean-contaminated. Conclusion: Overuse of antimicrobials was found in surgical antimicrobial prophylaxis. Ceftriaxone was preferred more than cefuroxime in all types of surgeries. No surgical site infections were reported. A follow-up comparative study is recommended to decrease antimicrobial use without increasing risk of surgical site infection.

Phytobeneficial and salt stress mitigating efficacy of IAA producing salt tolerant strains in Gossypium hirsutum.

Salinity is one of the major agricultural concern that significantly limits the crop productivity. The plant growth promoting rhizobacteria (PGPR) may contribute in sustainable crop production under salt stress. The current study was designed to isolate the Indole Acetic Acid (IAA) producing salt tolerant PGPR to promote the growth of cotton (Gossypium hirsutum, FH-142) and induce its salt stress tolerance. Ten Salt Tolerant (ST) bacterial strains were screened for their PGP trait in vitro and evaluated for their beneficial effect on cotton plants growth by plant-microbe interaction assay in lab and under natural condition. GC-MS analysis of the metabolites of the selected bacterial strains confirmed the presence of indolic compounds like indole, indole-3-butyramide, benzylmalonic acid and 4-methyl-2-pyrrolidinone. The bacterial isolates ST4, ST5, ST6, ST15, ST16, ST17, ST18, ST20, ST22 and ST25 were identified as Bacillus sp., B. sonorensis, B. cereus, B. subtilis, Brevibacillus sp. B. safensis, B. paramycoides, Bacillus sp., B. cereus and B. tequilensis respectively on the basis of 16S rDNA sequencing. Bacteria inoculated plants had a significant (P < 0.05) increase in percentage germination up to (31%), root length (17%) and shoot length (34%) in lab while in wire house pot experiments, maximum enhancement in root length (31%) and shoot length (29%) was observed. ST bacterial strains inoculation improved the chlorophyll content index (34%), relative water content (36%), leaf area (33%), absorption of K+ (28%) and decreased the uptake of Na+ (58%) from soil in plants under salt stress over control in pot experiment. These ST PGPR have the potential to act as plant defense agents by enhancing plant growth, productivity, and tolerance in saline environment.

A p-type PbS quantum dot ink with improved stability for solution processable optoelectronics.

A highly stable p-type PbS-QDs ink is prepared using a single-step biphasic ligand exchange route, overcoming instability encountered in previous reports. Chemical characterization of the ink reveals 3-mercaptopriopionic acid (MPA) capped QDs stable in benzylamine solvent over a period of weeks or longer. The film resistivity, 1.45 kΩ cm, is an order magnitude lower and surface roughness, ∼ 0.5 nm, is superior vs. PbS films reported so far, and proof of concept photovoltaic devices showed efficiency > 5.5%.

Heterometallic Actinide-Containing Photoresponsive Metal-Organic Frameworks: Dynamic and Static Tuning of Electronic Properties.

Acquiring fundamental knowledge of properties of actinide-based materials is a necessary step to create new possibilities for addressing the current challenges in the nuclear energy and nuclear waste sectors. In this report, we established a photophysics-electronics correlation for actinide-containing metal-organic frameworks (An-MOFs) as a function of excitation wavelength, for the first time. A stepwise approach for dynamically modulating electronic properties was applied for the first time towards actinide-based heterometallic MOFs through integration of photochromic linkers. Optical cycling, modeling of density of states near the Fermi edge, conductivity measurements, and photoisomerization kinetics were employed to shed light on the process of tailoring optoelectronic properties of An-MOFs. Furthermore, the first photochromic MOF-based field-effect transistor, in which the field-effect response could be changed through light exposure, was constructed. As a demonstration, the change in current upon light exposure was sufficient to operate a two-LED fail-safe indicator circuit.

GoAmazon2014/5 campaign points to deep-inflow approach to deep convection across scales.

A substantial fraction of precipitation is associated with mesoscale convective systems (MCSs), which are currently poorly represented in climate models. Convective parameterizations are highly sensitive to the assumptions of an entraining plume model, in which high equivalent potential temperature air from the boundary layer is modified via turbulent entrainment. Here we show, using multiinstrument evidence from the Green Ocean Amazon field campaign (2014-2015; GoAmazon2014/5), that an empirically constrained weighting for inflow of environmental air based on radar wind profiler estimates of vertical velocity and mass flux yields a strong relationship between resulting buoyancy measures and precipitation statistics. This deep-inflow weighting has no free parameter for entrainment in the conventional sense, but to a leading approximation is simply a statement of the geometry of the inflow. The structure further suggests the weighting could consistently apply even for coherent inflow structures noted in field campaign studies for MCSs over tropical oceans. For radar precipitation retrievals averaged over climate model grid scales at the GoAmazon2014/5 site, the use of deep-inflow mixing yields a sharp increase in the probability and magnitude of precipitation with increasing buoyancy. Furthermore, this applies for both mesoscale and smaller-scale convection. Results from reanalysis and satellite data show that this holds more generally: Deep-inflow mixing yields a strong precipitation-buoyancy relation across the tropics. Deep-inflow mixing may thus circumvent inadequacies of current parameterizations while helping to bridge the gap toward representing mesoscale convection in climate models.

Alterations of haemodynamic parameters in spontaneously hypertensive rats by Aristolochia ringens Vahl. (Aristolochiaceae).

Aristolochia ringens Vahl. (Aristolochiaceae (AR); mǎ dou líng) is used traditionally in Nigeria for the management of various disorders including oedema. Preliminary investigation revealed its modulatory effect on the cardiovascular system. This study was aimed at investigating the effect of the aqueous root extract of A. ringens (AR) on haemodynamic parameters of spontaneously hypertensive rats (SHRs). The effect of oral subacute (21 days) and intravenous acute exposure of SHRs to the extract were assessed using tail cuff and carotid artery canulation methods respectively. In the latter, the effect of chloroform, butanol and aqueous fractions of AR were also evaluated. The extract significantly reduced systolic and diastolic blood pressures in SHRs, with peak reductions of 20.3% and 26.7% respectively at 50 mg/kg by the 21st day of oral subacute exposure. Upon intravenous exposure, AR (50 mg/kg) reduced systolic and diastolic blood pressure by as much as 53.4 ± 2.2 and 49.2 ± 2.8 mmHg respectively. A dose-dependent reduction in heart rate, significant at 25 and 50 mg/kg was also observed. Hexamethonium (20 mg/kg) and atropine (1 mg/kg) inhibited the extract's reduction of systolic blood pressure, diastolic blood pressure and heart rate significantly. The extract's butanol fraction produced the greatest systolic and diastolic blood pressures reduction of 67.0 ± 3.8 and 68.4 mmHg respectively at 25 mg/kg and heart rate reduction of 40 ± 7 beats per minute at 50 mg/kg. HPLC analysis revealed the presence of 4-hydroxybenzoic acid and quercetin in AR. The extract's alterations of haemodynamic parameters in this study show that it has hypotensive effect on spontaneously hypertensive rats.

An Intervention Study for the Prevention and Control of Health Care-Associated Infection in the Critical Cares Area of a Tertiary Care Hospital in Saudi Arabia.

INTRODUCTION: Healthcare-associated infections (HAIs) are an infection that patients acquire during receiving treatment and care for the medical or surgical problem. OBJECTIVE: The objective of this study is to find the patterns of HAIs cases in the hospital and to know the impact of the intervention on prevention and control of health care associated infection. METHODOLOGY: This was prospective interventional study. RESULTS: The majority of cases of HAIs was reported from intensive care unit 47%. The most common site involved due to HAIs was catheter-associated urinary tract infection followed by central line-associated bloodstream infection. During the study period, around 28% reduction of cases were reported. During 6 months period (March to August 2016), around 540 cases were admitted in the critical care areas out of that 32 cases were reported as HAIs (5.9%) for the same period from (March to August 2017) was (3.4%), that difference came to be a statistically significant (χ2 = 4.12, P = 0.042, df = 1). CONCLUSION: This small study showed that strict implementation of care bundles with good compliance of hand hygiene, Personal protective equipment and antibiotic stewardship are helpful for prevention and control of hospital acquired infections. This study also demonstrated significant (28%) reduction of hospital acquired infections during the study period.

Visceral Leishmaniasis In Adults.

Visceral Leishmaniasis (also known as Kala Azar) is a parasitic infection caused by Leishmania Donovani in the East and Leishmania Infantum in the west. It is prevalent in many countries including India, Bangladesh, Nepal, Africa and part of America. The disease follows chronic course and is usually lethal if left untreated. It has also been reported from different parts of Pakistan, including Northern areas, Districts Mansehra & Abbottabad and Hilly areas of Khyber Pukhtoonkhawah. Most the cases have been reported in paediatric population. Except one case, reported previously from Abbottabad. The present two cases were also seen in adults.

Frequency and evaluation of the perceptions towards caesarean section among pregnant women attending public hospitals in Pakistan and the implications.

OBJECTIVES: There is increasing prevalence of caesarean sections (CS) worldwide; however, there are concerns about their rates in some countries, including potential fears among mothers. Consequently, we aimed to determine the frequency of CS, and explore patient's perception towards CS attending public hospitals in Pakistan, to provide future guidance. METHODS: A two-phased study design (retrospective and cross sectional) was adopted. A retrospective study was conducted to assess the frequency of CS over one year among four public hospitals. A cross sectional study was subsequently conducted to determine patients' perception towards CS attending the four tertiary care public hospitals in Quetta city, Pakistan, which is where most births take place. RESULTS: Overall prevalence of CS was 13.1% across the four hospitals. 728 patients were approached and 717 responded to the survey. Although 78.8% perceived CS as dangerous, influenced by education (p = 0.004), locality (p = 0.001) and employment status (p = 0.001), 74.5% of patients were in agreement that this is the best approach to save mother's and baby's lives if needed. 62% of respondents reported they would like to avoid CS if they could due to post-operative pain, and 58.9% preferred a normal delivery. There was also a significant association with education (p = 0.001) and locality (p = 0.001) where respondents considered normal vaginal delivery as painful. CONCLUSION: The overall frequency of CS approximates to WHO recommendations, although there is appreciable variation among the four hospitals. When it comes to perception towards CS, women had limited information. There is a need to provide mothers with education during the antenatal period, especially those with limited education, to accept CS where needed.

IMMUNOEXPRESSION OF TWIST IN DIFFERENT MORPHOLOGICAL VARIANTS OF AMELOBLASTOMAS.

BACKGROUND: Ameloblastoma is the most common and a clinically significant odontogenic tumour. The diagnosis and sub classification of ameloblastoma have been traditionally relied on histological assessment, but it is still a subject of debate. The aim of this study was to evaluate the immuno-expression of Twist in various subtypes of ameloblastomas and their corelation with various histological variants. METHODS: This cross-sectional study was conducted in the Department of Pathology, Post Graduate Medical Institute, Lahore between June to December 2013. Thirty cases of various types of Ameloblastomas were included in this study. Histological sub-classification of the tumours was performed based on WHO classification. Twist expression of these tumours was estimated by immunohistochemistry, performed on paraffin sections. RESULTS: Out of these thirty cases, 22 (73%) were newly diagnosed typical solid/multicystic intraosseous ameloblastoma, 2 (7%) cases belonged to recurrent ameloblastoma, and 3 (10%) each were diagnosed as peripheral/extraosseous ameloblastoma and ameloblastic carcinoma. On histopathological sub-classification of the newly diagnosed solid ameloblastoma, 8 cases were diagnosed as follicular ameloblastoma in which 3 cases (37.5%) were negatively stained, 4 cases (50%) were mild positive and 1 case (12.5%) was moderate positive with Twist immunostaining. Out of 5 cases of plexiform ameloblastoma 3 cases (60%) were mild positive. Out of 4 cases of acanthomatous ameloblastoma 2 (50%) were moderate positive and 2 cases (50%) were strong positive. All granular cell ameloblastoma stained positive. The only case of desmoplastic ameloblastoma was moderately positive. Both the cases of recurrent ameloblastoma were strongly positive. All 3 cases of peripheral ameloblastoma stained negatively. All ameloblastic carcinoma were strongly positive. CONCLUSION: Twist immunohistochemical analysis can be used as an adjuvant to H&E histopathological findings for proper categorization and grading of ameloblastoma especially in the clinically aggressive tumours.

Solvothermal preparation of ZnO nanorods as anode material for improved cycle life Zn/AgO batteries.

Nano materials with high surface area increase the kinetics and extent of the redox reactions, thus resulting in high power and energy densities. In this study high surface area zinc oxide nanorods have been synthesized by surfactant free ethylene glycol assisted solvothermal method. The nanorods thus prepared have diameters in the submicron range (300 ~ 500 nm) with high aspect ratio. They have uniform geometry and well aligned direction. These nanorods are characterized by XRD, SEM, Specific Surface Area Analysis, solubility in alkaline medium, EDX analysis and galvanostatic charge/discharge studies in Zn/AgO batteries. The prepared zinc oxide nanorods have low solubility in alkaline medium with higher structural stability, which imparts the improved cycle life stability to Zn/AgO cells.