Paramagnetic Properties of [AnIV(NO3)6]2- Complexes (An = U, Np, Pu) Probed by NMR Spectroscopy and Quantum Chemical Calculations.

Actinide +IV complexes with six nitrates [AnIV(NO3)6]2- (An = Th, U, Np, and Pu) have been studied by 15N and 17O NMR spectroscopy in solution and first-principles calculations. Magnetic susceptibilities were evaluated experimentally using the Evans method and are in good agreement with the ab initio values. The evolution in the series of the crystal field parameters deduced from ab initio calculations is discussed. The NMR paramagnetic shifts are analyzed based on ab initio calculations. Because the cubic symmetry of the complex quenches the dipolar contribution, they are only of Fermi contact origin. They are evaluated from first-principles based on a complete active space/density functional theory (DFT) strategy, in good accordance with the experimental one. The ligand hyperfine coupling constants are deduced from paramagnetic shifts and calculated using unrestricted DFT. The latter are decomposed in terms of the contribution of molecular orbitals. It highlights two pathways for the delocalization of the spin density from the metallic open-shell 5f orbitals to the NMR active nuclei, either through the valence 5f hybridized with 6d to the valence 2p molecular orbitals of the ligands, or by spin polarization of the metallic 6p orbitals which interact with the 2s-based molecular orbitals of the ligands.

Delving into theoretical and computational considerations for accurate calculation of chemical shifts in paramagnetic transition metal systems using quantum chemical methods.

The chemical shielding tensor for a paramagnetic system has been derived from the macroscopically observed magnetization using the perturbation theory. An approach to calculate the paramagnetic chemical shifts in transition metal systems based on the spin-only magnetic susceptibility directly evaluated from the ab initio Hilbert space of the electronic Zeeman Hamiltonian has been discussed. Computationally, several advantages are associated with this approach: (a) it includes the state-specific paramagnetic Curie (first-order) and Van Vleck (second-order) contributions of the paramagnetic ion to the paramagnetic chemical shifts; (b) thus it avoids the system-specific modeling and evaluating effectively in terms of the electron paramagnetic resonance (EPR) spin Hamiltonian parameters of the magnetic moment of the paramagnetic ion formulated previously; (c) it can be utilized both in the point-dipole (PD) approximation (in the long-range) and with the quantum chemical (QC) method based the hyperfine tensors (in the short-range). Additionally, we have examined the predictive performance of various density functional theory (DFT) functionals of different families and commonly used core-augmented basis sets for nuclear magnetic resonance (NMR) chemical shifts. A selection of transition metal ion complexes with and without first-order orbital contributions, namely the [M(AcPyOx)3(BPh)]+ complexes of M = Mn2+, Ni2+ and Co2+ ions and CoTp2 complex and their reported NMR chemical shifts are studied from QC methods for illustration.

Geometry and electronic structure of Yb(III)[CH(SiMe3)2]3 from EPR and solid-state NMR augmented by computations.

Characterization of paramagnetic compounds, in particular regarding the detailed conformation and electronic structure, remains a challenge, and - still today it often relies solely on the use of X-ray crystallography, thus limiting the access to electronic structure information. This is particularly true for lanthanide elements that are often associated with peculiar structural and electronic features in relation to their partially filled f-shell. Here, we develop a methodology based on the combined use of state-of-the-art magnetic resonance spectroscopies (EPR and solid-state NMR) and computational approaches as well as magnetic susceptibility measurements to determine the electronic structure and geometry of a paramagnetic Yb(III) alkyl complex, Yb(III)[CH(SiMe3)2]3, a prototypical example, which contains notable structural features according to X-ray crystallography. Each of these techniques revealed specific information about the geometry and electronic structure of the complex. Taken together, both EPR and NMR, augmented by quantum chemical calculations, provide a detailed and complementary understanding of such paramagnetic compounds. In particular, the EPR and NMR signatures point to the presence of three-centre-two-electron Yb-γ-Me-ß-Si secondary metal-ligand interactions in this otherwise tri-coordinate metal complex, similarly to its diamagnetic Lu analogues. The electronic structure of Yb(III) can be described as a single 4f13 configuration, while an unusually large crystal-field splitting results in a thermally isolated ground Kramers doublet. Furthermore, the computational data indicate that the Yb-carbon bond contains some π-character, reminiscent of the so-called α-H agostic interaction.

Bonding and Magnetic Trends in the [AnIII(DPA)3]3- Series Compared to the Ln(III) and An(IV) Analogues.

The crystal field parameters are determined from first-principles calculations in the [AnIII(DPA)3]3- series, completing previous work on the [LnIII(DPA)3]3- and [AnIV(DPA)3]2- series. The crystal field strength parameter follows the Ln(III) < An(III) < An(IV) trend. The parameters deduced at the orbital level decrease along the series, while J-mixing strongly impacts the many-electron parameters, especially for the Pu(III) complex. We further compile the available data for the three series. In some aspects, An(III) complexes are closer to Ln(III) than to An(IV) complexes with regard to the geometrical structure and bonding descriptors. At the beginning of the series, up to Pu(III), there is a quantitative departure from the free ion, especially for the Pa(III) complex. The magnetic properties of the actinides keep the trends of the lanthanides; in particular, the axial magnetic susceptibility follows Bleaney's theory qualitatively.

Are Actinyl Cations Good Probes for Structure Determination in Solution by NMR?

We report on NMR spectroscopy, CAS-based method calculations, and X-ray diffraction of AnV and AnVI complexes with a neutral and slightly flexible TEDGA ligand. After checking that pNMR shifts mainly arise from pseudocontact interactions, we analyze pNMR shifts considering the axial and rhombic anisotropy of the actinyl magnetic susceptibilities. The results are compared to those of a previous study performed on [AnVIO2]2+ complexes with dipicolinic acid. It is shown that 5f2 cations (PuVI and NpV) make very good candidates for determining the structure of actinyl complexes in solution by 1H NMR spectroscopy as shown by the invariance of the magnetic properties to the equatorial ligands, as opposed to the NpVI complexes with a 5f1 configuration.

Transcription factor BZR2 activates chitinase Cht20.2 transcription to confer resistance to wheat stripe rust.

The brassinosteroid pathway promotes a variety of physiological processes in plants and the brassinosteroid insensitive1-ethylmethane sulfonate suppressor (BES)/brassinazole-resistant (BZR) functions as one of its key regulators. We previously showed that the BES/BZR-type transcription factor TaBZR2 mediates the drought stress response in wheat (Triticum aestivum) by directly upregulating the transcriptional activity of glutathione S-transferase 1. However, the function of TaBZR2 in plants under biotic stresses is unknown. In this study, we found that transcript levels of TaBZR2 were upregulated in response to inoculation with wheat stripe rust fungus (Puccinia striiformis f. sp. tritici, Pst) and treatment with flg22 or an elicitor-like protein of Pst, Pst322. Wheat lines overexpressing TaBZR2 conferred increased resistance, whereas TaBZR2-RNAi lines exhibited decreased resistance to multiple races of Pst. TaBZR2 targeted the promoter of the chitinase gene TaCht20.2, activating its transcription. Knockdown of TaCht20.2 in wheat resulted in enhanced susceptibility to Pst, indicating the positive role of TaCht20.2 in wheat resistance. Upon Pst infection in vivo, the overexpression of TaBZR2 increased total chitinase activity, whereas RNAi-mediated silencing of TaBZR2 reduced total chitinase activity. Taken together, our results suggest that TaBZR2 confers broad-spectrum resistance to the stripe rust fungus by increasing total chitinase activity in wheat.

Dipolar and Contact Paramagnetic NMR Chemical Shifts in AnIV Complexes with Dipicolinic Acid Derivatives.

Actinide +IV complexes (AnIV = ThIV, UIV, NpIV, and PuIV) with two dipicolinic acid derivatives (DPA and Et-DPA) have been studied by 1H and 13C NMR spectroscopies and first-principles calculations. The Fermi contact and dipolar contributions to the actinide-induced shifts (AIS) are evaluated from a temperature dependence analysis, combined with ab initio results. It allows an experimental estimation of the axial anisotropy of the magnetic susceptibility Δχax and of the hyperfine coupling constants of the NMR-active nuclei. Due to the compactness of the coordination sphere, the magnetic anisotropy of the paramagnetic center is small, and this makes the contact contribution to be the dominant one, even on the remote atoms. The sign of the hyperfine coupling constants and related spin densities is alternating on the nuclei of the ligand cycle, denoting a preponderant spin polarization mechanism. This is well reproduced by unrestricted density functional theory (DFT) calculations. Those values are furthermore slightly decreasing in the actinide series, which indicates a small decrease of the covalency from UIV to PuIV.

A R2R3 MYB Transcription Factor, TaMYB391, Is Positively Involved in Wheat Resistance to Puccinia striiformis f. sp. tritici.

A biotrophic fungus, Puccinia striiformis f.sp. tritici (Pst), which causes stripe rust disease in wheat is the most yield-limiting factor in wheat production. Plants have complex defense mechanisms against invading pathogens. Hypersensitive response (HR), a kind of programmed cell death (PCD) at the infection site, is among these defense mechanisms. Transcription factors (TFs) play a crucial role in plant defense response against invading pathogens. Myeloblastosis (MYB) TFs are among the largest TFs families that are involved in response to both biotic and abiotic stresses. However, little is known about the mechanisms of MYB TFs during the interaction between wheat and the stripe rust fungus. Here, we identified an R2R3 MYB TF from wheat, designated as TaMYB391, and characterized its functional role during wheat-Pst interaction. Our data indicated that TaMYB391 is induced by Pst infection and exogenous application of salicylic acid (SA) and abscisic acid (ABA). TaMYB391 is localized in the nucleus of both wheat and Nicotiana benthamiana. Transient overexpression of TaMYB391 in N. benthamiana triggered HR-related PCD accompanied by increased electrolyte leakage, high accumulation of reactive oxygen species (ROS), and transcriptional accumulation of SA defense-related genes and HR-specific marker genes. Overexpression of TaMYB391 in wheat significantly enhanced wheat resistance to stripe rust fungus through the induction of pathogenesis-related (PR) genes, ROS accumulation and hypersensitive cell death. On the other hand, RNAi-mediated silencing of TaMYB391 decreased the resistance of wheat to Pst accompanied by enhanced growth of the pathogen. Together our findings demonstrate that TaMYB391 acts as a positive regulator of HR-associated cell death and positively contributes to the resistance of wheat to the stripe rust fungus by regulating certain PR genes, possibly through SA signaling pathways.

Hydrogeochemical characterization and quality assessment of groundwater resource in Savar - an industrialized zone of Bangladesh.

Savar Upazila in the Dhaka District is a rapidly expanding city with a diverse range of industries and agricultural activities. This expansion poses environmental challenges including the threat to groundwater contamination. Based on these considerations, the objective of this research is to carry out a shallow groundwater hydrogeochemical characterization and an assessment of the suitablity of the groundwater for drinking and irrigational purposes using a geochemical approach, multivariate statistical techniques, and some indices of groundwater quality. The hydrogeochemical analyses of 42 groundwater samples from shallow depths (18 - 76 m) showed that the order of concentrations of cations, anions, and metals was Ca2+ > Na+ > Mg2+ > K+, HCO3- > Cl- > SO42- > NO3-, and Cr > As > Pb > Mn > Fe, respectively. Weathering of silicates was found to be the most significant hydrogeochemical process governing the chemistry of groundwater. Cation exchange also plays a significant role in the evolution of the groundwater chemistry. Principal component analysis and hierarchical cluster analysis suggested that anthropogenic activities are influencing groundwater quality. A drinking water quality index map showed that about 91% of the groundwater samples were in the excellent category and suitable for human consumption, with only a few samples exceeding the standards of the WHO and Bangladesh for concentrations of Ca2+, Mg2+, HCO3-, Fe, Mn, and As. An analysis of irrigation quality parameters found that most of the groundwater samples were either excellent or good for agricultural uses, except for one sample in the Tetuljhora Union that was unsuitable based on residual sodium carbonate. This finding may be useful to local governments in understanding the current status of groundwater quality, tracking potential threats of contamination, and initiating appropriate measures for long-term groundwater resource management.

Assessment of self-medication practice and the potential to use a mobile app to ensure safe and effective self-medication among the public in Saudi Arabia.

Background: Self-medication (SM) plays an essential role in maintaining a good quality of life for individuals. Previous studies suggested that efforts are still needed to ensure the safe practice of SM. The advances in technology and the internet have granted the availability of abundant and easily accessed medication information. However, identifying the reliability of information could be a challenge for the public. This study aimed to investigate the attitude toward SM, determinants of SM, and knowledge about medication in Saudi Arabia. Also, this study aimed to assess the willingness to use a mobile app that would be specifically designed to guide the practice of SM. Methods: A cross-sectional study was conducted in a form of an online survey among the public in Saudi Arabia. QuestionPro® platform was utilized to collect data from respondents for two months. Statistical analysis was performed using IBM® SPSS® statistics version 26. Results: A total of 1226 individuals completed the questionnaire. The prevalence of SM practice was 59%. The most frequent reason for not practicing SM was the concern about the drug safety issues (38%). Significant statistical associations were identified between SM and several demographic variables, e.g., age, gender, education, health insurance, and having a chronic illness. Most respondents (82.7%) were aware of the necessity of improving SM practice. Knowledge about different aspects of SM (e.g., proper drug selection and administration) was evaluated based on the consumer's perspective. Our data showed that overall knowledge about SM was limited for many consumers. The assessment of the participant's willingness to use a SM app indicated that 47.6% were interested in using such app. This willingness was significantly associated with the consumer's attitude toward SM and being a chronically ill patient. Conclusion: SM is a common practice in Saudi Arabia. However, public awareness about SM is limited. So, implementing new strategies to enhance knowledge and ensure the safety of SM is important. A large proportion of participants were interested to use a SM app, which would improve SM practice. Therefore, we recommend developing a SM-oriented app to be used by the public in Saudi Arabia.

Temperature Dependence of 1 H Paramagnetic Chemical Shifts in Actinide Complexes, Beyond Bleaney's Theory: The AnVI O2 2+ -Dipicolinic Acid Complexes (An=Np, Pu) as an Example.

Actinide +VI complexes ( A n V I = U V I , N p V I and P u V I ) with dipicolinic acid derivatives were synthesized and characterized by powder XRD, SQUID magnetometry and NMR spectroscopy. In addition, N p V I and P u V I complexes were described by first principles CAS based and two-component spin-restricted DFT methods. The analysis of the 1 H paramagnetic NMR chemical shifts for all protons of the ligands according to the X-rays structures shows that the Fermi contact contribution is negligible in agreement with spin density determined by unrestricted DFT. The magnetic susceptibility tensor is determined by combining SQUID, pNMR shifts and Evans' method. The SO-RASPT2 results fit well the experimental magnetic susceptibility and pNMR chemical shifts. The role of the counterions in the solid phase is pointed out; their presence impacts the magnetic properties of the N p V I complex. The temperature dependence of the pNMR chemical shifts has a strong 1 / T contribution, contrarily to Bleaney's theory for lanthanide complexes. The fitting of the temperature dependence of the pNMR chemical shifts and SQUID magnetic susceptibility by a two-Kramers-doublet model for the N p V I complex and a non-Kramers-doublet model for the P u V I complex allows for the experimental evaluation of energy gaps and magnetic moments of the paramagnetic center.

TaAP2-15, An AP2/ERF Transcription Factor, Is Positively Involved in Wheat Resistance to Puccinia striiformis f. sp. tritici.

AP2 transcription factors play a crucial role in plant development and reproductive growth, as well as response to biotic and abiotic stress. However, the role of TaAP2-15, in the interaction between wheat and the stripe fungus, Puccinia striiformis f. sp. tritici (Pst), remains elusive. In this study, we isolated TaAP2-15 and characterized its function during the interaction. TaAP2-15 was localized in the nucleus of wheat and N. benthamiana. Silencing of TaAP2-15 by barley stripe mosaic virus (BSMV)-mediated VIGS (virus-induced gene silencing) increased the susceptibility of wheat to Pst accompanied by enhanced growth of the pathogen (number of haustoria, haustorial mother cells and hyphal length). We confirmed by quantitative real-time PCR that the transcript levels of pathogenesis-related genes (TaPR1 and TaPR2) were down-regulated, while reactive oxygen species (ROS)-scavenging genes (TaCAT3 and TaFSOD3D) were induced accompanied by reduced accumulation of H2O2. Furthermore, we found that TaAP2-15 interacted with a zinc finger protein (TaRZFP34) that is a homolog of OsRZFP34 in rice. Together our findings demonstrate that TaAP2-15 is positively involved in resistance of wheat to the stripe rust fungus and provides new insights into the roles of AP2 in the host-pathogen interaction.

Assessment of quality of work life (QWL) among healthcare staff of intensive care unit (ICU) and emergency unit during COVID-19 outbreak using WHOQoL-BREF.

OBJECTIVE: The study aimed to document the quality of work life (QWL) among healthcare staff of intensive care units (ICUs) and emergency units during COVID-19 outbreak using the WHOQoL-BREF. METHODS: A multicenter cross-sectional study was conducted for two months (May - June 2020) among healthcare staff working in intensive care units (ICUs) and emergency units of the hospitals under the National Guard Health Authority (NGHA) across five cities of Saudi Arabia. The study used the WHOQoL-BREF instrument to document the QWL through an electronic institutional survey. The data was analyzed through IBM SPSS version 23. The study was approved by an ethics committee. RESULTS: A total of 290 healthcare professionals responded to the survey. The mean overall quality of life score was 3.37 ± 0.97, general health = 3.66 ± 0.88, domains, i.e., physical = 11.67 ± 2.16, psychological = 13.08 ± 2.14, social = 13.22 ± 3.31 and environment = 12.38 ± 2.59. Respondents aged > 40 years, male gender, married status, being a physician and, having a work experience > 15 years and no extra working hours, had higher mean scores for several domains of Quality of life (QoL), overall QoL and general health (p < 0.05). CONCLUSION: The QWL among healthcare staff during COVID-19 pandemic was low. Demographic factors were mainly the determinants for a higher QWL while the variable of extra working hours was a determinant of lower QWL. Despite the pandemic, no COVID-19 related variables affected the work life of healthcare staff.

Concurrent validity of the Arabic version of General Medication Adherence Scale using two validated indirect adherences measures in Saudi patients with non-communicable diseases.

PURPOSE: This study aimed to evaluate the concurrent validity of the Arabic version of the General Medication Adherence Scale (GMAS) using two validated scales namely Adherence to Refills and Medications Scale (ARMS) and Medication Adherence Rating Scale (MARS) in Saudi patients with non-communicable diseases. METHODS: A cross sectional study was conducted for 2 months in out-patient departments at a tertiary care hospital in Khobar, Saudi Arabia. The study collected data from patients with chronic illnesses through convenience sampling. Pearson correlation (ρ) was conducted to report concurrent validity of GMAS. A correlation coefficient value ≥ 0.5 with p-value < 0.01 was considered threshold for establishing concurrent validity. The study was approved by an ethics committee (IRB-2019-05-002). RESULTS: A total of 406 patients responded to the study. The average age was 42.4 ± 5.94 years, and most patients were females (53.7%), married (70%), graduates (65.3%), employed (39.9%) and, had a monthly family income > SAR 10,000, i.e., USD 2666.2 (56.4%). The mean adherence scores obtained from MARS, ARMS and GMAS were 7.09, 19.9, and 27.4. The correlation (ρ) between GMAS and MARS scores was 0.65, and between GMAS and ARMS scores was -0.79, p < 0.01 for both comparisons. CONCLUSION: The concurrent validity of GMAS-AR was established in this study that would further substantiate psychometric properties of the scale in this population.

TaClpS1, negatively regulates wheat resistance against Puccinia striiformis f. sp. tritici.

BACKGROUND: The degradation of intracellular proteins plays an essential role in plant responses to stressful environments. ClpS1 and E3 ubiquitin ligase function as adaptors for selecting target substrates in caseinolytic peptidase (Clp) proteases pathways and the 26S proteasome system, respectively. Currently, the role of E3 ubiquitin ligase in the plant immune response to pathogens is well defined. However, the role of ClpS1 in the plant immune response to pathogens remains unknown. RESULTS: Here, wheat (Triticum aestivum) ClpS1 (TaClpS1) was studied and resulted to encode 161 amino acids, containing a conserved ClpS domain and a chloroplast transit peptide (1-32 aa). TaClpS1 was found to be specifically localized in the chloroplast when expressed transiently in wheat protoplasts. The transcript level of TaClpS1 in wheat was significantly induced during infection by Puccinia striiformis f. sp. tritici (Pst). Knockdown of TaClpS1 via virus-induced gene silencing (VIGS) resulted in an increase in wheat resistance against Pst, accompanied by an increase in the hypersensitive response (HR), accumulation of reactive oxygen species (ROS) and expression of TaPR1 and TaPR2, and a reduction in the number of haustoria, length of infection hypha and infection area of Pst. Furthermore, heterologous expression of TaClpS1 in Nicotiana benthamiana enhanced the infection by Phytophthora parasitica. CONCLUSIONS: These results suggest that TaClpS1 negatively regulates the resistance of wheat to Pst.

Crystallographic structure and crystal field parameters in the [AnIV(DPA)3]2- series, An = Th, U, Np, Pu.

The [AnIV(DPA)3]2- series with An = Th, U, Np, Pu has been synthesized and characterized using SC-XRD and vibrational spectroscopy. First principles calculations were performed, the total electron density is analyzed using the Quantum Theory of Atoms in Molecules. Crystal field parameters and strength parameters are deduced following a previous work on the LnIII analog series e.g. [J. Jung et al., Chem. - Eur. J., 2019, 25, 15112]. The trends in the parameters along the series are compared to the LnIII complexes. They evidence larger covalent interactions and larger J mixing.

Assessment of beverage consumption by young adults in Saudi Arabia.

OBJECTIVE: The primary objective was to assess beverage consumption pattern and calorie intake among undergraduate students on weekly and daily basis. Secondary objectives were to determine the relationship between demographic variables and beverage intake, assess mean differences in calorie intake between students' groups and, report the predictors of beverage consumption. METHODS: A cross-sectional study was conducted for 3 months (January-March 2019) among currently enrolled undergraduate students studying in 8 colleges of a public sector university in Dammam, Saudi Arabia. The study used the Arabic version of Beverage Frequency Questionnaire (BFQ) and collected data through purposive stratified sampling. Total intake in ml and calories in kcals were calculated. Data was analyzed through SPSS version 23 and the study was approved from ethics committee of the university (IRB-2019-05-021). RESULTS: A total of 507 students responded to the survey. The average volume of sugar sweetened beverages (SSBs), caffeine containing beverage (CCBs) and carbonated beverages (CarBs) consumed was 4.2 L, 4 L and 1.5 L per week and 650.6 ml, 575.2 ml and 224.6 ml per day, respectively. Average daily calorie intake from SSBs, CCBs and CarBs was 187.6 kcals, 87.6 kcals and 52.5 kcals, respectively. Body mass index (BMI) was significantly related to CCB (ρ = 0.130) and CarBs (ρ = 0.100) intake (mL) (p < 0.05). Mean difference in calorie intake was mostly significant (p < 0.05) when accounted for students' demographics, gender, BMI, residence, illness and, examination time, in case of SSBs, CCBs, CarBs and, all beverages. Averge % contribution towards total daily energy expenditure (TDEE) for SSBs, CCBs and CarBs were 10.2%, 6.3% and 2.8%, respectively. Year of study, BMI, residence and illness were predictors of SSBs consumption while BMI, residence and examination time were predictors of CCBs consumption. Gender and BMI were predictors of CarBs intake. CONCLUSION: There was a high consumption of beverages in students that was related to their demographic characteristics. There is a need to create awareness among the students regarding the detrimental effects of chronic consumption of these beverages.

Improving Electrochemical Pb2+ Detection Using a Vertically Aligned 2D MoS2 Nanofilm.

Recent advancements in MoS2 nanofilms have aided in the development for important water-related environmental applications. However, a MoS2 nanofilm-coated sensor has yet to have been applied for heavy metal detection in water-related environmental samples. In this study, a novel vertically aligned two-dimensional (2D) MoS2 (edge exposed) nanofilm was applied for in situ lead ion (Pb2+) detection. The developed sensor showed an excellent linear relationship toward Pb2+ between 0 and 20 ppb at -0.45 V vs Ag/AgCl using square wave anodic stripping voltammetry (SWASV) with the improved limit of detection (LOD) of 0.3 ppb in a tap water environment. The vertically aligned 2D MoS2 sensor exhibited improved detection sensitivity (2.8 folds greater than a previous metallic [Bi] composite electrode) with lower relative standard deviation for repetitive measurements (n = 11), indicating enhanced reproducibility for Pb2+ detection. The vertically aligned 2D MoS2 layers exhibited 2.6 times higher sensitivity than horizontally aligned 2D MoS2 (basal plane exposed). Density functional theory calculations demonstrated that adsorption energy of Pb on the MoS2 side edge was much higher (4.11 eV) than those on the basal plane (0.36 and 0.07 eV). In addition, the band gap center of vertical MoS2 was found to be higher than the Pb2+ → Pb reduction potential level and capable of reducing Pb2+. Overall, the newly developed vertically aligned 2D MoS2 sensor showed excellent performance for detecting Pb2+ in a real drinking water environment with good reliability.

Health care providers' perceptions regarding antimicrobial stewardship programs (AMS) implementation-facilitators and challenges: a cross-sectional study in the Eastern province of Saudi Arabia.

BACKGROUND: Infections result from invasions of an organism into body tissues leading to diseases and complications that might eventually lead to death. Inappropriate use of antimicrobials has led to development of antimicrobial resistance (AMR) which has been associated with increased mortality, morbidity and health costs. Antimicrobial stewardship (AMS) programs are designed to ensure appropriate selections of an effective antimicrobial drugs and optimizing antibiotic use to minimize antibiotic resistance by implementing certain policies, strategies and guidelines. The aim of this study was to investigate practitioners' perceptions regarding AMS implementation and to identify challenges and facilitators of these programs execution. METHODS: Cross-sectional study among health care providers in Eastern province of Saudi Arabia Hospitals. The data was collected using a survey including questions about demographic data and information about clinicians' (physicians, pharmacists and nurses) previous experience with AMS and prescribing of antibiotics, the level of knowledge and attitudes regarding AMS programs' implementation. RESULTS: More than 50% of clinicians (N = 184) reported lack of awareness of AMS programs and their components, whereas 71.2% do not have previous AMS experience. The majority of clinicians (72.3%) noticed increasing number of AMR infections over the past 5 years and (69.6%) were involved in care of patients with an antibiotic-resistant infection. Around 77.2% of respondents reported that formulary management can be helpful for AMS practice and majority of respondents (79.9%) reported that the availability of pathogens and antimicrobial susceptibility testing can be helpful for AMS. Major barriers to AMS implementation identified were lack of internal policy/guidelines and specialized AMS information resources. Lack of administrative awareness about AMS programs; lack of personnel, time limitation, limited training opportunities, lack of confidence, financial issue or limited funding and lack of specialized AMS information resources were also reported 65.8%, 62.5%, 60.9%, 73.9%, 50%, 54.3 and 74.5%, respectively. CONCLUSION: Our study identified comprehensive education and training needs for health care providers about AMS programs. Furthermore, it appears that internal policy and guidelines need revision to ensure that the health care providers work consistently with AMS. Future research must focus on the benefit of implementing AMS as many hospitals are not implementing AMS as revealed by the clinicians. We recommend policy makers and concerned health authorities to consider the study findings into account to optimize AMS implementation.

Centimeter-Scale 2D van der Waals Vertical Heterostructures Integrated on Deformable Substrates Enabled by Gold Sacrificial Layer-Assisted Growth.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) such as molybdenum or tungsten disulfides (MoS2 or WS2) exhibit extremely large in-plane strain limits and unusual optical/electrical properties, offering unprecedented opportunities for flexible electronics/optoelectronics in new form factors. In order for them to be technologically viable building-blocks for such emerging technologies, it is critically demanded to grow/integrate them onto flexible or arbitrary-shaped substrates on a large wafer-scale compatible with the prevailing microelectronics processes. However, conventional approaches to assemble them on such unconventional substrates via mechanical exfoliations or coevaporation chemical growths have been limited to small-area transfers of 2D TMD layers with uncontrolled spatial homogeneity. Moreover, additional processes involving a prolonged exposure to strong chemical etchants have been required for the separation of as-grown 2D layers, which is detrimental to their material properties. Herein, we report a viable strategy to universally combine the centimeter-scale growth of various 2D TMD layers and their direct assemblies on mechanically deformable substrates. By exploring the water-assisted debonding of gold (Au) interfaced with silicon dioxide (SiO2), we demonstrate the direct growth, transfer, and integration of 2D TMD layers and heterostructures such as 2D MoS2 and 2D MoS2/WS2 vertical stacks on centimeter-scale plastic and metal foil substrates. We identify the dual function of the Au layer as a growth substrate as well as a sacrificial layer which facilitates 2D layer transfer. Furthermore, we demonstrate the versatility of this integration approach by fabricating centimeter-scale 2D MoS2/single walled carbon nanotube (SWNT) vertical heterojunctions which exhibit current rectification and photoresponse. This study opens a pathway to explore large-scale 2D TMD van der Waals layers as device building blocks for emerging mechanically deformable electronics/optoelectronics.