A Theoretical Investigation for Exploring the Potential Performance of Non-Fullerene Organic Solar Cells Through Side-Chain Engineering Having Diphenylamino Groups to Enhance Photovoltaic Properties.

The development of ecofriendly fabrication phenomenon is essential requirement for commercialization of non-fullerene acceptors. Recently, end-capped modeling is employed for computational design of five non-fullerene acceptors to elevate various photovoltaic properties. All new molecules are formulated by altering the peripheral acceptors of CH3-2F and DFT methodology is employed to explore the opto-electronic, morphological and charge transfer analysis. From the computational investigation, all reported molecules manifested red shifted absorption with remarkable reduced band gap. Among investigated molecules, FA1-FA3 evinced effectively decreased value of band gaps and designed molecules have low excitation energy justifying proficient charge transference. The lower values of binding energy of FA1 and FA2 suggest their facile exciton dissociation leading to improved charge mobility. By blending with J61 donor, FA4 have sufficiently enhanced value of VOC (1.72 eV) and fill factor (0.9228). Energy loss of the model (R) is 0.57 eV and statistical calculation demonstrate that all our modified molecules except FA3 has profoundly reduced energy loss compelling in its pivotal utilization. From accessible supportive outcomes of recent investigation, it is recommended that our modified chromophore exhibit remarkable noteworthy applications in solar cells for forthcoming innovations.

Effect of medication adherence on quality of life, activation measures, and health imagine in the elderly people: a cross-sectional study.

BACKGROUND: Usually, old age brings a poor quality of life due to illness and frailty. To prolong their lives and ensure their survival, all elderly patients with chronic diseases must adhere to their medications. In our study, we investigate medication adherence for elderly patients and its impact on the general health of the patient. METHODS: We implemented a cross-sectional survey-based study with four sections in April 2022 in Saudi Arabia. Data about the participants' demographic characteristics, the Morisky Medication Adherence Scale, Patient Activation Measure (PAM) 13, and EQ-5D-5 L. RESULTS: A total of 421 patients participated in this study, their mean age was 60.4 years, and most of them were males. Most of our population is living independently 87.9%. The vast majority of people have a low adherence record in the Morisky Medication Adherence Scale (8-MMAS) classes (score = < 6). Moreover, the average PAM13 score is 51.93 (Level2) indicating a low level of confidence and sufficient knowledge to take action. Our analysis showed a significant correlation between socioeconomic status and medication adherence. Also, there was an association between housing status and medication adherence. On the other hand, we found no correlation between medication adherence and quality of life (QOL) by EQ-5D-5 L. CONCLUSION: Medication adherence is directly affected by living arrangements, as patients who live with a caretaker who can remind them to take their medications at the appropriate times have better medication adherence than those who live alone. Medication adherence was also significantly influenced by socioeconomic status, perhaps as a result of psychological effects and the belief of the lower-salaried population that they would be unable to afford the additional money required to cure any comorbidities that arose as a result of the disease. On the other hand, we did not find any correlation between medication adherence and quality of life. Finally, awareness of the necessity of adherence to medication for the elderly is essential.

Comparing the safety and effectiveness of various umbilical cord milking techniques and delayed cord clamping in full-term and preterm infants: A systematic review and meta-analysis.

We compare the hematocrit, hemoglobin, need for transfusion, recurrent phototherapy, serum bilirubin level, and serum ferritin at different time frames for the umbilical cord milking (UCM) and delayed cord clamping (DCC) in both full-term and preterm infants. A comprehensive search through various databases aimed to compare UCM and DCC studies until May 2nd, 2023. Cochrane and NIH tools assessed RCTs and cohorts, respectively. Meta-analysis employed Review Manager 5.4 software, calculating MD and RR with 95% CIs for continuous and dichotomous data. We included 20 studies with a total of 5189 infants. Regarding preterm infants, hematocrit level showed no significant difference between intact Umbilical Cord Milking (iUCM) compared to DCC (MD = -0.24, 95% CI [-1.11, 0.64]). Moreover, Neonatal death incidence was significantly higher with the UCM technique in comparison to DCC (RR = 1.28, 95% CI [1.01 to 1.62]). Regarding term and late preterm infants, Hematocrit level showed no significant difference between the iUCM or cUCM techniques compared to DCC (MD = 0.21, 95% CI [-1.28 to 1.69]), (MD = 0.96, 95% CI [-1.02 to 2.95]), respectively. UCM led to a higher risk of neonatal death in preterm infants compared to DCC. However, the incidence of polycythemia was lower in the UCM group. Additionally, UCM was associated with higher rates of severe IVH events. Based on these findings, DCC may be preferred due to its lower incidence of severe IVH and neonatal death.

Nous comparons l'hématocrite, l'hémoglobine, le besoin de transfusion, la photothérapie récurrente, le taux de bilirubine sérique et la ferritine sérique à différentes périodes pour la traite du cordon ombilical (UCM) et le clampage retardé du cordon (DCC) chez les nourrissons nés à terme et prématurés. Une recherche complète dans diverses bases de données visait à comparer les études UCM et DCC jusqu'au 2 mai 2023. Les outils Cochrane et NIH ont évalué les ECR et les cohortes, respectivement. La méta-analyse a utilisé le logiciel Review Manager 5.4, calculant le MD et le RR avec des IC à 95 % pour les données continues et dichotomiques. Nous avons inclus 20 études portant sur un total de 5 189 nourrissons. Concernant les nourrissons prématurés, le niveau d'hématocrite n'a montré aucune différence significative entre la traite du cordon ombilical intact (iUCM) et la DCC (DM = -0,24, IC à 95 % [-1,11, 0,64]). De plus, l'incidence des décès néonatals était significativement plus élevée avec la technique UCM qu'avec la technique DCC (RR = 1,28, IC à 95 % [1,01 à 1,62]). Concernant les nourrissons à terme et peu prématurés, le niveau = 0,21, IC à 95 % [-1,28 à 1,69]), (DM = 0,96, IC à 95 % [-1,02 à 2,95]), respectivement. L'UCM a entraîné un risque plus élevé de décès néonatal chez les nourrissons prématurés par rapport au DCC. Cependant, l'incidence de la polyglobulie était plus faible dans le groupe UCM. De plus, l'UCM était associée à des taux plus élevés d'événements IVH graves. Sur la base de ces résultats, le DCC peut être préféré en raison de sa plus faible incidence d'IVH grave et de décès néonatals. d'hématocrite n'a montré aucune différence significative entre les techniques iUCM ou cUCM par rapport à la technique DCC (DM.

Nurses' Perception of Safety Culture in Medical-Surgical Units in Hospitals in Saudi Arabia.

Introduction: Patient safety captures the essence of the primary principle of medical ethics, primum non nocere, first do no harm; this is an important concern in the health care system. Nurses are indispensable members of this system and are the largest group of health care providers involved in the direct delivery of patient care. As an integral part of the health care system, it is important to know nurses' opinions on patient safety culture. Objectives: First, to evaluate and measure the existing safety culture and safety of patients in medical-surgical wards (MSW) in hospitals located in the Qassim region, in the Kingdom of Saudi Arabia. Second, to survey the opinion of registered nurses and supervisors/managers about safety culture and issues concerned with safety in hospitals in the region. Materials and Methods: A validated cross-sectional survey, namely the Hospital Survey on Patient Safety Culture (HSOPSC), was used. This survey queried 300 nurses in different MSWs in four hospitals in the Qassim Region. Results: Overall, a positive culture of safety exists in MSWs, with 69% of RNs rating their wards as having great/excellent safety culture. Notably, some participants felt it was problematic that blame was assigned to nurses for reported errors. While 55.9% of participants noted that all errors or narrowly avoided errors had been reported, less than half actually reported errors in the last year. Conclusion: The perceived safety culture was largely positive; however, the results also indicated that a culture of safety comes with some risk and blame.

Perceived quarantine competence, attitudes and practices among the public during the coronavirus pandemic: A Saudi descriptive study.

BACKGROUND: The unavailability of data on the long-term efficacy of COVID-19 vaccines and of effective specific treatment, in addition to the emergence of new COVID-19 variants, makes nonpharmaceutical measures a mainstay for preventing the spread of infection. The policy responses of governments to the pandemic should be integrated with public behavioral changes. This study examines public attitudes, practices and perceived quarantine competency in Saudi Arabia during the COVID-19 pandemic. METHODS: A cross-sectional descriptive design using an online survey was employed. Convenience and snowball sampling were adopted, and 1022 valid responses were received. FINDINGS: Most respondents demonstrated satisfactory practices, including wearing face masks (76.5%), keeping a safe distance (97.8%) and appropriate hand hygiene (99.2%). Fear of stigma (8.9%) and of financial consequences (0%) were minimal drivers of underreporting of symptoms among the respondents, whereas uncertainty of the relevance of symptoms (30.3%) was a main cause of not reporting to health authorities. Most participants (73.4%) abided by government instructions due to fear of infection rather than of legal penalties. Participants, especially females and Saudi citizens, reported a high level of perceived quarantine competence (12.9 ± 2.59). Spearman's rho correlation showed a significant positive association between wearing face masks and other precautionary practices, including keeping a safe distance (0.25, P < .01) and frequent handwashing (0.224, P < .01), which rules out the concern that wearing face masks would result in less adherence of the participants to other protective measures. CONCLUSION: Our findings suggest that COVID-19 awareness programs should focus more on males and non-Saudi populations. We also recommend the development of screening protocols and education programs for asthmatic patients in Saudi Arabia to avoid the consequences of confusing COVID-19 symptoms with those of asthma.

Caring for Women With Postpartum Depression in Saudi Arabia: Nurses' and Midwives' Opinions About Their Roles.

The current cross-sectional study was conducted to investigate nurses' and midwives' opinions about their roles in caring for women with postpartum depression (PPD) in Saudi Arabia. Convenience sampling was used to recruit 181 nurses and 141 midwives. A self-administered questionnaire was used to collect data. Participants lacked experience assessing and managing PPD and providing health education and counseling to mothers about PPD. Moreover, participants underestimated the importance of their roles in preventing PPD risk factors, and detecting, assessing, and managing PPD. Findings show significant differences between nurses' and midwives' opinions, with more frequency of agreement among nurses than midwives regarding their roles in caring for women with PPD. Continuing health education programs for nurses and midwives are recommended to improve knowledge, skills, and awareness of their roles in assessing and managing PPD. [Journal of Psychosocial Nursing and Mental Health Services, 58(7), 42-51.].

Workforce requirements for comprehensive ischaemic stroke care in a developing country: the case of Saudi Arabia.

BACKGROUND: Ischaemic stroke care requires a co-ordinated multi-disciplinary approach to optimise patient outcomes. Current care provision in Saudi Arabia is below international recommendations, and with increasing patient numbers, variable access to new therapies, and sub-optimal co-ordination of staff, the Kingdom's Ministry of Health has prioritised strategies to develop stroke care. Our objective was to use local epidemiological data to predict stroke incidence and to combine this with international staffing recommendations to estimate future staff requirements and their costs over a 10-year period. METHODS: We researched existing stroke services and staff availability within Saudi Arabia to establish current provision, undertook epidemiological modelling to predict stroke incidence, and used international staffing recommendations for acute and rehabilitation services to develop a care pathway to provide state-of-the-art stroke services. This information was used to determine the additional staff requirements, and their costs, across the Kingdom. RESULTS: Our research concluded that current staff numbers and services are inadequate to cope with the projected increase in the number of stroke cases. In order to provide acute and rehabilitation services which use the latest technologies, re-organisation of existing staff and services would be required, together with significant investment in new staff across several disciplines. An estimated additional 43.8 full-time equivalent stroke neurologists would be required, plus 53.5 full-time equivalent interventional neuroradiologists in addition to expansion of occupational therapy and psychology services. The total cost of additional staff over 10 years was estimated to be 862 390 778 Saudi Riyals ($229 970 874). CONCLUSIONS: Providing high-quality care for ischaemic stroke patients would involve significant investment in new staff in Saudi Arabia. Further research is required on the applicability of international staffing ratios to countries where there is a significant workforce gap. Nevertheless, this analysis provides a framework to inform stroke care planning and can be adapted to other regions or countries.

Designing efficient materials for high-performance of non-fullerene organic solar cells through side-chain engineering on DBT-4F derivatives by non-fused-ring electron acceptors.

CONTEXT: For the advancement in fields of organic and perovskite solar cells, various techniques of structural alterations are being employed on previously reported chromophores. In this study, the end-capped engineering is carried out on DBT-4F (R) by modifying terminal acceptors to improve optoelectronic and photovoltaic attributes. Seven molecules (AD1-AD7) are modeled using different push-pull acceptors. DFT/B3LYP/6-31G along with its time-dependent approach (TD-DFT) are on a payroll to investigate ground state geometries, absorption maxima (λmax), energy gap (Eg), excitation energy (Ex), internal reorganization energy, light harvesting efficiency (LHE), dielectric constant, open circuit voltage (VOC), fill factor (FF), etc. of OSCs. AD1 displayed the lowest band gap (1.76 eV), highest λmax (876 nm), lowest Ex (1.41 eV), and lowest binding energy (0.21 eV). Among various calculated parameters, all of the sketched molecules demonstrated greater dielectric constant when compared to R. The highest dielectric constant was exhibited by AD3 (56.26). AD5 exhibited maximum LHE (0.9980). Lower reorganization energies demonstrated improved charge mobility. AD5 and AD7 (1.63 and 1.68 eV) have higher values of VOC than R (1.51 eV). All novel molecules having outperforming attributes will be better candidates to enhance the efficacy of OSCs for future use. METHODS: Precisely, a DFT and TD-DFT analysis on all of the proposed organic molecules were conducted, using the functional MPW1PW91 at 6-31G (d,p) basis set to examine their optoelectronic aspects, additionally the solvent-state computations were studied with a TD-SCF simulation. For all these simulations, Guassian 09 and GuassView 5.0 were employed. Moreover, the Origin 6.0, Multiwfn 3.8, and PyMOlyze 1.1 software were utilized for the visual depiction of the graphs of absorption, TDM, and DOS, respectively of the studied molecules. A number of crucial aspects such as FMOs, bandgaps, light-harvesting efficiency, electrostatic potential, dipole moment, ionization potential, open-circuit voltage, fill factor, binding energy, interaction coefficient, chemical hardness-softness, and electrophilicity index were also investigated for the studied molecules.

A band gap and photoluminescence properties engineering in BaO semiconductor for ultraviolet (UV) photodetector applications: A comprehensive role of co-doping.

We report on ultra-violet (UV) photodetectors based on BaO nanoparticles by the detailed investigation of band gap and photoluminescence properties. The BaO nanomaterials were fabricated by the modified sol-gel technique. The innovation of co-doping can modulate the photoluminescence or sensing properties by narrowing the band gap related to enhancing the high carrier concentration, higher electronic lifetime, and low carriers recombination. It is investigated that the BaO nanoparticles with co-doping reveals a highly reduced band gap and exceptional photoluminescence properties as compared to the pristine BaO nanoparticles due to hindering carrier,s recombination for Ultra-violet (UV) photodetectors. The optical studies revealed that the addition of co-dopants in BaO host material creates new energy sites, so the band gap declines up to 1.31 eV as compared to that of pristine BaO (1.36 eV). The photoluminescence properties recorded with photoluminescence (PL) spectroscopy were recorded which revealed the decrease in PL intensity due to the hindering of carriers recombination with the addition of co-dopant metal ions. Furthermore, the inclusion of co-dopant metals results in an improvement in electrical conductivity because of a decline in carrier recombination, according to an I-V characteristic study. This factor contributes to enhance the photoluminescence properties of BaO which, in turn, contributes to enhance the sensing capability of the photodetector device. These obtained features modify optoelectronic properties are far superior as compared to that of previously reported literature on BaO nanomaterials, and the synthesized BaO semiconductor material becomes a potential candidate for efficient use in the ultraviolet (UV) photodetectors device applications.

A theoretical investigation for improving the performance of non-fullerene organic solar cells through side-chain engineering of BTR non-fused-ring electron acceptors.

In the current quantum chemical study, indacenodithiophene donor core-based the end-capped alterations of the reference chromophore BTR drafted eight A2-A1-D-A1-A2 type small non-fullerene acceptors. All the computational simulations were executed under MPW1PW91/6-31G (d, p) level of DFT. The UV-Vis absorption, open circuit voltage, electron affinity, ionization potential, the density of states, reorganization energy, orbital analysis, and non-covalent interactions were studied and compared with BTR. Several molecules of our modeled series BT1-BT8 have shown distinctive features that are better than those of the BTR. The open circuit voltage (VOC) of BT5 has a favorable impact, allowing it to replace BTR in the field of organic solar cells. The charge carrier motilities for proposed molecules generated extraordinary findings when matched to the reference one (BTR). Further charge transmission was confirmed by creating the complex with a PM6 donor molecule. The remarkable dipole moment contributes to the formation of non-covalent bond interactions with chloroform, resulting in superior charge mobility. Based on these findings, it can be said that every tailored molecule has the potential to surpass chromophore molecule (BTR) in OSCs. So, all tailored molecules may enhance the efficiency of photovoltaic cells due to the involvement of potent terminal electron-capturing acceptor2 moieties. Considering these obtained results, these newly presented molecules can be regarded for developing efficient solar devices in the future.

Stroke and high-risk TIA outcomes with reduction of treatment duration when treatment initiated in emergency rooms (SHORTER-study).

BACKGROUND: Following transient ischemic attack (TIA) and minor stroke, the risk of recurrent stroke can be significantly reduced with short-duration dual antiplatelet therapy (DAPT). We wish to investigate whether 10 days of DAPT is as effective as 21 days' treatment. STUDY DESIGN: This is an open-label, randomized, parallel-group study comparing whether 10 days of DAPT treatment (ASA + clopidogrel) is non-inferior to 21 days of DAPT in patients with acute ischemic stroke (AIS) or high-risk TIA. In both groups, DAPT is started within 24 hours of symptom onset. This study is being conducted in approximately 15 study sites in the Kingdom of Saudi Arabia. The planned sample size is 1932. OUTCOMES: Non-inferiority of 10 days compared to 21 days of DAPT in the prevention of the composite endpoint of stroke and death at 90 days in AIS/TIA patients. The primary safety outcome is major intra-cranial and systemic hemorrhage. STUDY PERIOD: Enrolment started in the second quarter of 2023, and the completion of the study is expected in the fourth quarter of 2025. DISCUSSION: The trial is expected to show that 10 days of DAPT is non-inferior for the prevention of early recurrence of vascular events in patients with high-risk TIAs and minor strokes.

Characterizing short germline-specific promoters with a range of expression levels in C. elegans.

A core tenet of synthetic biology is that well-characterized regulatory elements are essential for engineering biological systems. Here, we characterize the specificity and expression levels of 18 short (254 to 880 bp) candidate germline promoters using a single-copy gfp reporter assay in C. elegans . Six promoters resulted in ubiquitous expression, three did not drive detectable expression, and nine were germline-specific. Several promoters drove stronger germline expression than the commonly-used mex-5 promoter. The promoters range across expression levels and facilitate, for example, low expression of toxic transgenes or high expression of gene editing enzymes, and their compactness facilitates gene synthesis.

Enhanced electrical and magnetic properties of (Co, Yb) co-doped ZnO memristor for neuromorphic computing.

We investigate the morphological, electrical, magnetic, and resistive switching properties of (Co, Yb) co-ZnO for neuromorphic computing. By using hydrothermal synthesized nanoparticles and their corresponding sputtering target, we introduce Co and Yb into the ZnO structure, leading to increased oxygen vacancies and grain volume, indicating grain growth. This growth reduces grain boundaries, enhancing electrical conductivity and room-temperature ferromagnetism in Co and Yb-doped ZnO nanoparticles. We present a sputter-grown memristor with a (Co, Yb) co-ZnO layer between Au electrodes. Characterization confirms the ZnO layer's presence and 100 nm-thick Au electrodes. The memristor exhibits repeatable analog resistance switching, allowing manipulation of conductance between low and high resistance states. Statistical endurance tests show stable resistive switching with minimal dispersion over 100 pulse cycles at room temperature. Retention properties of the current states are maintained for up to 1000 seconds, demonstrating excellent thermal stability. A physical model explains the switching mechanism, involving Au ion migration during "set" and filament disruption during "reset." Current-voltage curves suggest space-charge limited current, emphasizing conductive filament formation. All these results shows good electronic devices and systems towards neuromorphic computing.

The psychological experience of nursing students in their internship year during the COVID-19 pandemic in Saudi Arabia.

The COVID-19 pandemic produced challenges and troubling issues in Saudi Arabia and worldwide. During the height of the pandemic, the psychological status of nursing students was complicated by challenges that affected their educational future. We used qualitative approach to explore the psychological status of 20 Saudi nursing students from Nursing College in their internship program during the COVID-19 pandemic by investigating their perceptions, experiences, and challenges. Thematic analysis methods were used to present the data as themes and subthemes. Themes that emerged during interviews revealed: Interns' experiences from the outbreak; Perceptions of students toward COVID-19; Mental distress associated with the situation; Level of support from either or both university authorities or hospital education and training departments; Financial challenges; and Readiness to complete a nursing internship. COVID-19 presented several challenges to Saudi nursing students in internship year including psychological distress in several aspects such as fear of infection for themselves and their families. However, this study findings do not apply to all nursing students as it only included nursing interns actively engaged in clinical practice. Additional studies are required to examine how the clinical practice of internships varied across the country during any epidemic situation.

Dandy-Walker Syndrome: Delayed Acute Presentation With Unusual Symptoms.

Dandy-Walker syndrome (DWS) is a rare congenital brain malformation defined by the presence of an expanded posterior fossa, full or partial absence of the cerebellar vermis, and a cystic expansion of the fourth ventricle. We report an 18-month-old girl with DWS presenting with atypical clinical manifestations and unusual symptoms. She initially presented with persistent vomiting and abdominal pain for four days, not responding to antiemetic medication. In addition, she was found to have abnormal postural arching of the back, extension of the lower limbs, and neck extension. MRI and CT head suggested Dandy-Walker syndrome with hydrocephalus (the lateral ventricle, third ventricle, and fourth ventricle are all significantly dilated with evidence of trans-ependymal cerebrospinal fluid permeation, severe compression anterior displacement of the brain stem). The patient underwent urgent, lifesaving right sub-occipital craniotomy, evacuation, and decompression of the posterior fossa cyst and external ventricular drain (EVD) insertion along with left supra-tentorial EVD insertion. A series of brain magnetic imaging and CT brain post-procedure studies showed a significant reduction in the size of the ventricular system and mass effect on the brain stem.

Competency in ECG Interpretation and Arrhythmias Management among Critical Care Nurses in Saudi Arabia: A Cross Sectional Study.

Background: Electrographic interpretation skills are important for healthcare practitioners caring for patients in need of cardiac assessment. Competency in ECG interpretation skills is critical to determine any abnormalities and initiate the appropriate care required. The purpose of the study was to determine the level of competence in electrocardiographic interpretation and knowledge in arrhythmia management of nurses in critical care settings. Methods: A descriptive cross-sectional design was used. A convenience sample of 255 critical care nurses from 4 hospitals in the Al-Madinah Region in Saudi Arabia was used. A questionnaire was designed containing a participant's characteristics and 10 questions with electrocardiographic strips. A pilot test was carried out to evaluate the validity and reliability of the questionnaire. Descriptive and bivariate analyses were conducted using an independent t-test, one-way ANOVA, or bi-variate correlation tests, as appropriate. A statistical significance of p < 0.05 was assumed. Results: Females comprised 87.5% of the sample, and the mean age of the sample was 32.1 (SD = 5.37) years. The majority of the participants (94.9%) had taken electrocardiographic interpretation training courses. The mean total score of correct answers of all 10 ECG strips was 6.45 (±2.54) for ECG interpretation and 4.76 (±2.52) for arrhythmia management. No significant differences were observed between ECG competency level and nursing experience or previous training. Nurses working in the ICU and CCU scored significantly higher than those working in ED. Conclusions: The electrocardiographic knowledge in ECG interpretation and arrhythmia management of critical care nurses is low. Therefore, improving critical care nurses' knowledge of ECGs, identification, and management of cardiac arrhythmias is essential.

Hydrothermal Extraction of Amorphous Silica from Locally Available Slate.

Slate is a naturally available aluminous silicate based material and can be used as a good source for silica extraction. In the current investigation, the slate sample was passed through calcination and acid leaching processes to decrease alumina contents and other major constituents. Silica extraction was performed by alkaline hydrothermal treatment of a given slate sample followed by acidic precipitation. Different steps, including the effect of concentration of sodium hydroxide solution, reaction time, the ratio of the mass of sample to volume of alkaline solution, the temperature of dispersion, and pH of the filtrate, were investigated to extract the maximum amount of pure amorphous silica. The extracted silica was physicochemically analyzed through XRF, XRD, FT-IR spectroscopy, and SEM techniques. The amorphous nature of the extracted silica is evident from XRD and SEM studies, while FT-IR studies support its purity, showing peaks of only Si-O-Si bonds. The purity of the extracted silica was further confirmed via XRF spectroscopic analysis and a hydrofluoric acid test.

Enhancement of the Optical and Dielectric Properties at Low Frequency of (Sr1-xCax)5Ti4O13, (0 ≤ x ≤ 0.06) Structure Ceramics.

Low loss Ruddlesden-Popper (RP) series, i.e., (Sr1-xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06, has been synthesized by a mixed oxide route. In this work, the substitution of Ca2+ cation in Sr5Ti4O13 sintered ceramics was chosen to enhance the structural, optical, and dielectric properties of the product. It was found that the Ca2+ content has significant effects on enhancing the dielectric properties as compared to Mn and glass additions. It was observed that the relative density, band gap energy, and dielectric loss (tangent loss) increase while relative permittivity decreases along with Ca2+ content. High relative density (96.7%), low porosity, and high band gap energy (2.241 eV) values were obtained in (Sr1-xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06 sintered ceramics. These results will play a key role in the application of dielectric resonators.

Effects of Strontium on the Structural, Optical, and Microwave Dielectric Properties of Ba2Ti9O20 Ceramics Synthesized by a Mixed Oxide Route.

Solid solutions of Sr-doped barium nonatitanate (Ba2Ti9O20) ceramics were synthesized by a mixed oxide route, studied their structural, microstructural, optical, and microwave dielectric properties were studied. X-ray diffraction (XRD) has been used to reveal the structure and crystallite size of doped Ba2Ti9O20 ceramics. Rietveld refinements of XRD patterns revealed that all of the ceramics have a tetragonal structure with space group I4/m. The surface morphologies of all the samples were characterized by using scanning electron microscopy (SEM). Fourier transform infrared (FT-IR) studies gave the O-H and Ti-O modes of vibrations. The stretching modes of Ti-O and O-H were noted at 1400, 2960, 3700, and near to 440 cm-1, respectively. The band gap energy decreases with increasing Sr2+ contents, and a high value (2.12 eV) was observed in the base sample. The microwave dielectric properties of the ceramic samples were studied at different frequencies ranging from 1 to 2 GHz by using impedance spectroscopy. The obtained results showed the suitability of these samples for microwave dielectric resonator (antenna) applications.

Consequences of SARS-CoV-2 Infection in Pregnant Women and Their Infants: A Systematic Review.

Coronavirus disease 2019 (COVID-19) is a worldwide health problem, particularly for pregnant women. This review assesses the effects of COVID-19 on pregnant women and their infants. A systematic search was performed of studies published on PubMed, Web of Science, Google Scholar, and Embase from January 2020 to January 2021, without restriction by language. This review included 27 studies (22 from China, one from the United States, one from Honduras, one from Italy, one from Iran, and one from Spain), which cumulatively evaluated 386 pregnant women with clinically confirmed COVID-19 and their 334 newborns. Of the 386 pregnant women, 356 had already delivered their infants, four had medical abortions at the time of research, 28 were still pregnant, and two died from COVID-19 before they were able to give birth. Cesarean sections were performed on 71% of pregnant women with COVID-19 to give birth. Fever and cough were common symptoms among women. Premature rupture of membranes, distress, and preterm birth were pregnancy complications. Low birth weight and a short gestational age were common outcomes for newborns. The common laboratory findings among pregnant women were lymphopenia, leukocytosis, and elevated levels of C-reactive protein. Chest computed tomography revealed abnormal viral lung changes in 73.3% of women. Eleven infants tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There was no evidence of vertical transmission. Most infants were observed to have lymphopenia and thrombocytopenia. The clinical features of pregnant women were found to be similar to those of generally infected patients. There is evidence of adverse pregnancy and neonatal outcomes caused by COVID-19.