Prevalence of anxiety and depression among medical students of shifa college of medicine

To yield information regarding the prevalence of anxiety and depression among medical students in Islamabad and to emphasize on the need of psychological and mental well being of medical students.Methods: This is a cross-sectional study done at Shifa College of Medicine. A questionnaire was administered to 361 students who were present at the time of distribution and were consented. The instrument used to assess anxiety and depression level was the Aga khan University Anxiety and Depression Scale (AKUADS). The data collected was tabulated and analyzed using SPS v. 16.Results: Out of a total of 500 students in a five year MBBS program at Shifa College of Medicine, 402 students were present at the time of the survey out of which, 361 students agreed to participate. The response rate was 89.8%. According to the AKUADS, 39.6% of students were found to have anxiety and depression. Among them, 28.1 % were males and 49.5% were females. Hence, anxiety and depression was more prevalent among females. First year medical students were found to have more anxiety and depression (52.6%) as compared to the rest.Conclusion: Anxiety and Depression is widely seen among medical students. This study highlights the graveness of the situation, and the need for trained psychiatrists to deal with this enormous disease burden. There is a further need to explore the factors that influence anxiety and depression among medical students and its impact on students’ academic performance

Mechanical exfoliation and layer number identification of single crystal monoclinic CrCl3

After the recent finding that CrI3, displays ferromagnetic order down to its monolayer, extensive studies have followed to pursue new two-dimensional (2D) magnetic materials. In this article, we report on the growth of single crystal CrCl3 in the layered monoclinic phase. The system after mechanical exfoliation exhibits stability in ambient air (the degradation occurs on a time scale at least four orders of magnitude longer than is observed for CrI3). By means of mechanical cleavage and atomic force microscopy (AFM) combined with optical identification, we demonstrate the systematic isolation of single and few layer flakes onto 270 nm and 285 nm SiO2/Si~(100) substrates with lateral size larger than graphene flakes isolated with the same method. The layer number identification has been carried with statistically significant data, quantifying the optical contrast as a function of the number of layers for up to six layers. Layer dependent optical contrast data have been fitted within the Fresnel equation formalism determining the real and imaginary part of the wavelength dependent refractive index of the material. A layer dependent (532 nm) micro-Raman study has been carried out down to two layers with no detectable spectral shifts as a function of the layer number and with respect to the bulk

Microscopic and spectroscopic studies of CrCl3 functionalised two dimensional magnetic material

After the recent discovery of the persistent existence of ferromagnetism down to the mono- layer of CrI3, a significant amount of research has been conducted to explore and identify the novel properties of Cr-based magnetic materials. For our project, we have purposefully chosen to study the CrCl3 material due to its distinctive behavior of exhibiting weak van der Waals interaction between the layers as well as in-plane ferromagnetic order. In this thesis work, we reported the growth of monoclinic single crystal CrCl3 and confirmed its crystal phase and purity through X-ray diffraction (XRD) and Raman spectroscopy. Our observations confirmed the higher stability of exfoliated CrCl3 under ambient conditions compared to other chromium halides (CrX3). Its degradation rate is approximately four orders of magnitude slower than CrI3. Then we present a detailed step-by-step procedure for the exfoliation of CrCl3 on diverse substrates, with the objective of determining the optimal SiO2 thickness that enhances the visibility of single and few layers of CrCl3. To demonstrate the effectiveness of our approach, we conducted experiments on 270 nm and 285 nm SiO2/Si (100) substrates, exfoliating flakes of larger dimensions than graphene using the same methodological steps. The layer number identification was carried out using a large dataset, which helped to measure optical contrast accurately based on the number of layers, up to six layers. The optical contrast data were analyzed using the Fresnel’s equation formalism to determine the real and imaginary components of the wavelength-dependent refractive index of the material. Consequently, we calculate the layer and wavelength- dependent absorbance and reflectance, followed by the evaluation of optical contrast curves that illustrate significantly high contrast only within specific wavelength bands. This finding is subsequently validated through experimental UV-Vis absorbance data. Moreover, a micro-Raman study was performed at a wavelength of 532 nm to study the layers, down to two layers, and no significant spectral shifts were observed in relation to the layer number or bulk material. Here, We analyzed mechanically exfoliated CrCl3 flakes using various techniques to investi- gate the electronic structures of pure, oxidized, and defective monolayer (ML) CrCl3 phases. Surface oxidation of CrCl3 flakes occurs upon air exposure, resulting in the formation of oxidized O-CrCl3 structures and chromium oxide at the flake edges. Pure ML CrCl3 is an insulator with a band gap of 2.8 eV. Oxidized and Cl defective phases of ML CrCl3 in exfoliated CrCl3 flakes exhibit in-gap spin-polarized states and notable modifications of the electronic band structures. The Cl 2p core level data exhibits distinct signatures indicating the presence of Cl vacancies on the surface. Then we performed high resolution photo-emission (PE) spectroscopy on air and UHV cleaved CrCl3 and found a stable, but only partially ordered Cl-O-Cr phase on the surface. By studying electronic core levels (Cl 2p, Cr 2p, and 3p), we quantify the electron charge transfer to the Cr atom resulting from this modification and the increased exchange in- teraction between metal and ligand atoms. The analysis of multiplet components using the CMT4XPS code demonstrates the favourability of charge transfer and the reduced crystal field due to the established polarization field. Contrary to claims suggesting the presence of significant Cl and Cr atomic vacancies, we exclude this possibility based on the observed sign and magnitude of the shift in binding energy of core level electrons. Our methodological approach holds significant potential for accurately determining the structure of ordered sub-oxide phases in mono or bi-layer Cr trihalides. At first, we focused on measuring bulk or thick samples. Later, with the help of specific beam arrangements, we were able to expand our measurements to thin flakes and quantify their layers using Scanning Photoelectron Microscopy (SPEM). Our experiment successfully confirmed the existence of an ordered phase on the surface. However, we also discovered that the formation of Cl vacancies, which make room for oxygen, is limited in thinner flakes compared to thicker ones due to the restricted diffusion process. To support our findings, we compared them with other surface-sensitive techniques like Kelvin Probe Force Microscopy (KPFM). Our observations revealed that the work function increases with the thickness of flakes, which may be related to the increasing density of Cl vacancies acting as dissociation centers

Perception of MBBS Students on Hybrid Teaching in Covid-19 Era: A Survey of Public Sector Medical University

Aim: To explore the perceptions, limitations and recommendations for hybrid teaching. Methodology: This is a cross sectional study, conducted in the academic session of 2021 among the students of Dow medical college including third years through final years. Convenient sampling is used. The questionnaire was created on Google and forms were emailed to the students. Likert scale is applied to record the responses. Results: Total of 102 students of both genders filled the questionnaire. Students were mostly from third year, fourth year and final year. Most of the students had no previous experience of e- learning. 36.3% students agreed that hybrid teaching is better than face to face or online sessions alone. 31.4% were of the opinion that hybrid teaching covers the strong points of both face to face and online teaching. Conclusion: Covid-19 makes classroom medical education difficult but blended or hybrid teaching and learning would seem to be the perfect solution to overcome the challenges. Keywords: Hybrid teaching, distance learning, Covid 19</jats:p

Light Induced Electron-Phonon Scattering Mediated Resistive Switching in Nanostructured Nb Thin Film Superconductor

The elemental Nb is mainly investigated for its eminent superconducting properties. In contrary, we report of a relatively unexplored property, namely, its superior optoelectronic property in reduced dimension. We demonstrate here that nanostructured Nb thin films (NNFs), under optical illumination, behave as room temperature photo-switches and exhibit bolometric features below its superconducting critical temperature. Both photo-switch and superconducting bolometric behavior are monitored by its resistance change with light in visible and near infrared (NIR) wavelength range. Unlike the conventional photodetectors, the NNF devices switch to higher resistive states with light and the corresponding resistivity change is studied with thickness and grain size variations. At low temperature in its superconducting state, the light exposure shifts the superconducting transition towards lower temperature. The room temperature photon sensing nature of the NNF is explained by the photon assisted electron-phonon scattering mechanism while the low temperature light response is mainly related to the heat generation which essentially changes the effective temperature for the device and the device is capable of sensing a temperature difference of few tens of milli-kelvins. The observed photo-response on the transport properties of NNFs can be very important for future superconducting photon detectors, bolometers and phase slip based device applications

Metallic Interface Induced Ionic Redistribution within Amorphous MoO3 Films

Advanced Materials Interfaces published by Wiley-VCH GmbH.The phase evolution and ionic redistribution in amorphous MoO3 films, deposited on metallic aluminium (Al) and copper (Cu) substrates and subjected to distinct thermal treatments, are systematically investigated in this work. It is shown that the metallic interface significantly modifies the formation and dynamics of oxygen vacancies within the resulted structure, reducing the oxygen content of the MoO3 up to x < 2.94. The concentration of the oxygen vacancies can also be extended to the bulk via thermal treatment up to 400 °C. It is demonstrated that the MoO3 structure on metallic substrates is affected either by the diffusion of the metallic atoms inserted from the interface, which results in a formation of the meta-stable alloy phases in case of Cu, or by the introduction of the oxygen vacancies into the crystalline matrix in case of Al. The oxygen vacancy density in the MoO3 films with a metallic interface can be tuned via optimal choice of the metal and treatment parameters such as temperature and oxygen partial pressure. Furthermore, the intrinsic defects present in the amorphous structure enhance the ionic mobility and diffusion of the metallic ions inside the crystalline structure.11Nsciescopu

In Search of Disorder Transitions and Defects Within Cu2ZnSn(S,Se)4‐Based Absorber Layers via Temperature‐Dependent Raman Spectroscopy Technique

The temperature-dependent (25-300 degrees C) disorder transitions analyzed via Raman spectroscopic technique for the different non-stoichiometric Cu2ZnSn(S,Se)(4) (CZTSSe) thin films are demonstrated. In the thin films prepared with different Zn conditions, i.e., in Zn-1 (Zn-poor), the density of the A-type defect cluster [Zn-Cu + V-Cu] increases with temperature; however, it slightly decreases and remains constant for Zn-rich samples, i.e., Zn-2 and Zn-3. At the same time, the density of the B-type defect cluster [2Zn(Cu) + Zn-Sn] increases with increasing temperature and Zn content. The observations further reveal that Zn concentration has less impact on V-Cu formation; therefore, above the optimum Cu-poor and Zn-rich conditions, Zn-Cu shallow donors negatively influence the kesterite device performances. Finally, solar cells based on all the CZTSSe thin-film samples (Zn-1, Zn-2, and Zn-3) are fabricated in which a device based on Zn-2 exhibits excellent power conversion efficiency of approximate to 11.0% with open-circuit voltage of 478 mV, short-circuit current of 35.51 mA cm(-2), and fill factor of 64%, respectively

Emerging oxidized and defective phases in low-dimensional CrCl₃

Emerging defect- and oxidation-induced extrinsic phases are discovered in low-dimensional CrCl3.</p

Emerging oxidized and defective phases in low-dimensional CrCl3

Two-dimensional (2D) magnets such as chromium trihalides CrX3 (X = I, Br, Cl) represent a frontier for spintronics applications and, in particular, CrCl3 has attracted research interest due its relative stability under ambient conditions without rapid degradation, as opposed to CrI3. Herein, mechanically exfoliated CrCl3 flakes are characterized at the atomic scale and the electronic structures of pristine, oxidized, and defective monolayer CrCl3 phases are investigated employing density functional theory (DFT) calculations, scanning tunneling spectroscopy (STS), core level X-ray photoemission spectroscopy (XPS), and valence band XPS and ultraviolet photoemission spectroscopy (UPS). As revealed by atomically resolved transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis, the CrCl3 flakes show spontaneous surface oxidation upon air exposure with an extrinsic long-range ordered oxidized O-CrCl3 structure and amorphous chromium oxide formation on the edges of the flakes. XPS proves that CrCl3 is thermally stable up to 200 degrees C having intrinsically Cl vacancy-defects whose concentration is tunable via thermal annealing up to 400 degrees C. DFT calculations, supported by experimental valence band analysis, indicate that pure monolayer (ML) CrCl3 is an insulator with a band gap of 2.6 eV, while the electronic structures of oxidized and Cl defective phases of ML CrCl3, extrinsically emerging in exfoliated CrCl3 flakes, show in-gap spin-polarized states and relevant modifications of the electronic band structures