Charge Transport, Conductivity and Seebeck Coefficient in Pristine and TCNQ Loaded Preferentially Grown Metal Organic Frameworks

This investigation on Metal-Organic Framework (MOF) HUKUST-1 films focuses on comparing the undoped pristine state and with the case of doping by TCNQ infiltration of the MOF pore structure. We have determined the temperature dependent charge transport and p-type conductivity for HKUST-1 films. Furthermore, the electrical conductivity and the current-voltage characteristics have been characterized in detail. Because the most common forms of MOFs, bulk MOF powders, do not lend themselves easily to electrical characterization investigations, here in this study the electrical measurements were performed on dense, compact surface-anchored metal-organic framework (SURMOF) films. These monolithic, well-defined, and (001) preferentially oriented MOF thin films are grown using quasi-liquid phase epitaxy (LPE) on specially functionalized silicon or borosilicate glass substrates. In addition to the pristine SURMOF films also the effect of loading these porous thin films with TCNQ has been investigated. Positive charge carrier conduction and a strong anisotropy in electrical conduction was observed for highly oriented SURMOF films and corroborated with Seebeck Coefficient measurements. Van der Pauw four-point Hall sample measurements provide important insight into the electrical behavior of such porous and hybrid organic-inorganic crystalline materials, which renders them attractive for potential use in microelectronic and optoelectronic devices and thermoelectric applications

Identifying the Professional Characteristics of Researchers in Educational Fields at Sudanese Universities from the Views of Educational Experts

The present study aims at identifying the characteristics, research abilities and skills that the researcher in the educational fields should possess and their role in enriching research outcomes. A second aim was whether these characteristics are met by Sudanese University staff embarked on educational research. The study adopted the descriptive correlational and induction methods. The university staff members who conduct research in the educational fields constitute the population of the present study. A systematic stratified sample of 48 lecturers from 12 universities was selected and a Likert type-based questionnaire was applied. Three main domains that help in doing educational research were identified. The questionnaire is composed of these main domains; the intellectual characteristic (11 items), the psycho-social characteristics (12 items), and research skills (15 items). Results of the pilot study showed that the questionnaire achieved good reliability, validity and internal consistency coefficients and hence was suitable for the purpose of this study. The SPSS program was used for data analysis. Findings showed significant positive correlation between the intellectual characteristic and years of experience (0.03) and the professional level of members of staff (0.001).The psycho-social characteristics were not significantly correlated with years of experience while they are positively correlated with the professional level of members of staff (0.001). Although 66.6% of the subjects were found to command the necessary research skills, yet they were not significantly correlated with years of experience. These findings are discussed in the light of relevant literature. More specifically, from the professional and ethical stance, Sudanese universities are expected to pay more attention to capacity building in educational scientific research since it is the cornerstone of human development

Intraoperative Hemodynamic Changes in Dexamethasone and Magnesium Sulphate as an Adjunct to Bupivacaine for Caudal Blockade Anesthesia and Analgesia in Children Undergoing Lower Abdominal Surgeries

Background: It is possible to achieve caudal analgesia by administering a little amount of local anesthetic into the caudal canal. There have been good analgesic effects reported for Dexamethasone with Magnesium Sulfate. Objective: The aim of the work was to evaluate and compare between dexamethasone and magnesium sulphate regarding duration and first time of rescue analgesic requirement intraoperative and to measure intraoperative hemodynamic changes (MAP, HR, SPO2) sedation and the amount of sedative and analgesic required. Patients and Methods: Pediatric patients aged 2 to 6 years of both genders were included in this Randomized double blind clinical study. They were all scheduled for Lower Abdominal Surgeries. Before surgery, a computer-generated randomization table randomly assigned patients into two dexamethasone (D) and magnesium (M) groups, each were 20. Caudal block was administered to patients in Group D using dexamethasone 0.1mg/kg in conjunction with bupivacaine 0.25% at 2mg/kg. Group M: patients received a 0.25 percent bupivacaine/magnesium sulphate caudal block of 5mg kg. The patients were submitted to clinical evaluation, laboratory investigations and monitoring pre and intraoperative hemodynamic changes. Results: Regarding demographic data, there was no significant difference between both groups (P > 0.05). Regarding HR distribution at different times pre and intraoperatively, there was no significant difference between both groups (p value >0.05). Regarding mean arterial blood pressure (MAP) at different times pre and intraoperatively, there was no significant difference between both groups (p value >0.05). Regarding the arterial oxygen saturation at different times, there was no statistical significant difference between both groups (p value >0.05). Conclusion: The analgesic profile of bupivacaine-induced caudal blocking children undergoing lower abdominal surgery was improved with magnesium (5 mg/kg) and Dexamethasone (0.1mg/kg)

Broadband Dielectric Spectroscopic Detection of Ethanol: A Side-by-Side Comparison of ZnO and HKUST-1 MOFs as Sensing Media

The most common gas sensors are based on chemically induced changes in electrical resistivity and necessarily involve making imperfect electrical contacts to the sensing materials, which introduce errors into the measurements. We leverage thermal- and chemical-induced changes in microwave propagation characteristics (i.e., S-parameters) to compare ZnO and surface-anchored metal-organic-framework (HKUST-1 MOF) thin films as sensing materials for detecting ethanol vapor, a typical volatile organic compound (VOC), at low temperatures. We show that the microwave propagation technique can detect ethanol at relatively low temperatures (\u3c100 \u3e°C), and afford new mechanistic insights that are inaccessible with the traditional dc-resistance-based measurements. In addition, the metrological technique avoids the inimical measurand distortions due to parasitic electrical effects inherent in the conductometric volatile organic compound detection

Broadband Dielectric Spectroscopic Detection of Ethanol: A Side-by-Side Comparison of ZnO and HKUST-1 MOFs as Sensing Media†,‡

The most common gas sensors are based on chemically induced changes in electrical resistivity and necessarily involve making imperfect electrical contacts to the sensing materials, which introduce errors into the measurements. We leverage thermal- and chemical-induced changes in microwave propagation characteristics (i.e., S-parameters) to compare ZnO and surface-anchored metal–organic-framework (HKUST-1 MOF) thin films as sensing materials for detecting ethanol vapor, a typical volatile organic compound (VOC), at low temperatures. We show that the microwave propagation technique can detect ethanol at relatively low temperatures (<100 °C), and afford new mechanistic insights that are inaccessible with the traditional dc-resistance-based measurements. In addition, the metrological technique avoids the inimical measurand distortions due to parasitic electrical effects inherent in the conductometric volatile organic compound detection

Broadband Dielectric Spectroscopic Detection of Aliphatic Alcohol Vapors With Surface-Mounted HKUST-1 MOFs as Sensing Media

We leveraged chemical-induced changes to microwave signal propagation characteristics (i.e., S-parameters) to characterize the detection of aliphatic alcohol (methanol, ethanol, and 2-propanol) vapors using TCNQ-doped HKUST-1 metal-organic-framework films as the sensing material, at temperatures under 100 °C. We show that the sensitivity of aliphatic alcohol detection depends on the oxidation potential of the analyte, and the impedance of the detection setup depends on the analyte-loading of the sensing medium. The microwaves-based detection technique can also afford new mechanistic insights into VOC detection, with surface-anchored metal-organic frameworks (SURMOFs), which is inaccessible with the traditional coulometric (i.e., resistance-based) measurements

Broadband Dielectric Spectroscopic Detection of Aliphatic Alcohol Vapors with Surface-Mounted HKUST-1 MOFs as Sensing Media †

We leveraged chemical-induced changes to microwave signal propagation characteristics (i.e., S-parameters) to characterize the detection of aliphatic alcohol (methanol, ethanol, and 2-propanol) vapors using TCNQ-doped HKUST-1 metal-organic-framework films as the sensing material, at temperatures under 100 ◦C. We show that the sensitivity of aliphatic alcohol detection depends on the oxidation potential of the analyte, and the impedance of the detection setup depends on the analyte-loading of the sensing medium. The microwaves-based detection technique can also afford new mechanistic insights into VOC detection, with surface-anchored metal-organic frameworks (SURMOFs), which is inaccessible with the traditional coulometric (i.e., resistance-based) measurements

Spectroscopic Investigation of Bianthryl‐Based Metal–Organic Framework Thin Films and Their Photoinduced Topotactic Transformation

Metal organic frameworks MOFs have gained a large amount of interest because of their periodic and modular structure. These features allow easy prediction of the physical and chemical properties of an organic chromophore, acting as a linker in the MOF. In the present work, a bianthryl BA chromophore, equipped with metal coordinating carboxylate groups, is studied to construct a photoluminescent Zn BA surface anchored MOF SURMOF thin film. The Zn BA SURMOF, in response to prolonged UV light irradiation under ambient conditions, exhibits prominent changes in the ground and excited state optical properties, without losing its crystalline structure. A detailed spectroscopic study using UV vis, infra red, Raman, and electron paramagnetic resonance EPR reveals that in the presence of O2 a photoinduced topotactic transformation is initiated by the formation of singlet oxygen, which then reacts with the BA linkers to form endoperoxid

Primary School Teachers’ Perspectives on ADHD in Alkadrow, Khartoum, Sudan

Background: Attention deficit hyperactivity disorder, which is a prevalent neurodevelopmental condition, commonly manifests during early childhood and has the potential to adversely affect an individual’s social, academic, and occupational performance in multiple settings. Students with ADHD may struggle with attention, focus, listening, and completing schoolwork. Additionally, they may exhibit restless or disruptive behavior in class and may have learning disabilities that affect their academic performance. The aim of this study was to explore the perspectives of primary school teachers on ADHD in Alkadrow, Khartoum, Sudan. Methods: A descriptive cross-sectional study was conducted in Alkadrow-Bahri locality, Sudan, over a period of three to six months in 2022. The study population included primary school teachers who had taught for at least one year and encountered at least one student with ADHD. A convenience sampling technique was used to select a minimum of 59 participants, and data were collected using a self-administered questionnaire with closed-ended questions. SPSS version 23 was used to analyze the data, including descriptive statistics and inferential statistics such as chi-square tests and logistic regression analysis. Results: The study had 59 participants, with the majority being female and in the age group of 41–45 years. The participants were mostly married and had obtained psychology courses, with a bachelor’s degree being the most common level of education. Many participants had over 20 years of teaching experience. Regarding the attitude toward attention deficit hyperactivity, most participants strongly agreed that they did have a negative/positive attitude toward it, and a majority agreed or were neutral toward ADHD. However, in the case of attention deficit hyperactivity, a significant percentage of participants disagreed or strongly disagreed with the statement. Conclusion: The study found that most participants had a negative attitude toward student referrals for medical care and believed that most symptoms of ADHD can be lowered by aging. Additionally, more than half strongly disagreed that punishment has a positive effect on ADHD

Chromatographic Separation, Total Determination and Chemical Speciation of Mercury in Environmental Water Samples Using 4-(2-Thiazolylazo) Resorcinol-Based Polyurethane Foam Sorbent-Packed Column

A simple method has been developed for quantitative retention of traces of mercury(II) ions from aqueous media using polyurethane foams (PUFs) loaded with 4-(2-thiazolylazo) resorcinol (TAR). The kinetics and thermodynamics of the sorption of mercury(II) ions onto PUFs were studied. The sorption of mercury(II) ions onto PUF follows a first-order rate equation with k = 0.176 ± 0.010 min−1. The negative values of ΔH and ΔS may be interpreted as the exothermic chemisorption process and indicative of a faster chemisorption onto the active sites of the sorbent. The sorption data followed Langmuir, Freundlich and Dubinin-Radushkevich (D–R) isotherm models. The D-R parameters β, KDR and E were 0.329 mol2 kJ−2, 0.001 μmol g−1 and 1.23 ± 0.07 kJ/mol for the TAR-loaded PUFs, respectively. An acceptable retention and recovery (99.6 ± 1.1%) of mercury(II) ions in water at ≤10 ppb by the TAR-treated PUFs packed columns were achieved. A retention mechanism, involving absorption related to “solvent extraction” and an “added component” for surface adsorption, was suggested for the retention of mercury(II) ions by the used solid phase extractor. The performance of TAR-immobilized PUFs packed column in terms of the number (N), the height equivalent to a theoretical plate (HETP), the breakthrough and critical capacities of mercury(II) ion uptake by the sorbent packed column were found to be 50.0 ± 1.0, 1.01 ± 0.02 mm, 8.75 and 13.75 mg/g, respectively, at 5 mL/min flow rate