38 research outputs found

    The role of professors and students in developing and revising the universities curriculum in Afghanistan

    Get PDF
    The main aim of this research is the professors and students involvement in the main decision-making of developing and revising the Afghanistan university curriculum? The researcher has used the latest studies related to this issue in other countries for the field research, a mixed-method (quantitative and qualitative), were used. The results of previous studies in other countries indicate that the role of professors and students in Developing or revising the university curriculum are highly significant, the present study indicates that despite the efforts of the Afghan Ministry of Higher Education in revising the curriculum, there are still significant issues. In achieving an ideal curriculum, otherwise, the curriculum would face serious challenges

    The Effect of Aromatherapy with Lavender on Pain of Needle Insertion and Severity of Restless Legs Syndrome in Hemodialysis Patients; a Systematic Review and Meta-analysis

    Get PDF
    Introduction: Pain experienced during the insertion of a catheter into the arteriovenous fistula (AVF) and restless legs syndrome (RLS) are prevalent issues among Hemodialysis (HD) patients. The primary objective of this systematic review and meta-analysis was to consolidate the findings from randomized clinical trial (RCT) studies examining the impact of aromatherapy with lavender on the pain associated with AVF catheter insertion and RLS in HD patients. Methods: A systematic search was conducted on PubMed, Web of Science, Scopus, Cochrane, Embase, ClinicalTrials.gov, and Google Scholar search engine from inception to August 1, 2022, using keywords extracted from Medical Subject Headings, such as “Aromatherapy”, “Lavender”, “Arteriovenous fistula”, “Pain”, “Restless legs syndrome”, and “Hemodialysis”. Results: Finally, eleven articles were included in this systematic review and meta-analysis. The results showed that aromatherapy reduced the average pain of catheter insertion in AVF compared to the control group (Standard Mean Difference: -1.60, 95% Confidence Interval: -2.32 to -0.87, Z=4.32, I2:90.3%, P<0.001). Also, aromatherapy massage reduced the average severity of RLS compared to the control group, which was statistically significant (Weighted Mean Difference: -13.21, 95% Confidence Interval: -17.50 to -8.91, Z=6.03, I2:93.0%, P<0.001). Also, the subgroup analysis showed that lavender in the intervention group significantly decreased the pain intensity compared to the "no intervention" group (P<0.001), yet it was not significant compared to the placebo group (P=0.12). Conclusion: In summary, the findings indicate a notable reduction in catheter insertion pain in AVF and relief from RLS among HD patients through the use of lavender essential oil. As a result, future research is encouraged to include a comparison of lavender's effects with those of a placebo group

    Evolution of the m-plane Quantum Well Morphology and Composition within a GaN/InGaN Core-Shell Structure

    Get PDF
    GaN/InGaN core-shell nanorods are promising for optoelectronic applications due to the absence of polarization-related electric fields on the sidewalls, a lower defect density, a larger emission volume and strain relaxation at the free surfaces. The core-shell geometry allows the growth of thicker InGaN shell layers, which would benefit the efficiency of light emitting diodes. However, the growth mode of such layers by metal organic vapor phase epitaxy is poorly understood. Through a combination of nanofabrication, epitaxial growth and detailed characterization, this work reveals an evolution in the growth mode of InGaN epitaxial shells, from a two dimensional (2D) growth mode to three dimensional (3D) striated growth without additional line defect formation with increasing layer thickness. Measurements of the indium distribution show fluctuations along the directions, with low and high indium composition associated with the 2D and 3D growth modes, respectively. Atomic steps at the GaN/InGaN core-shell interface were observed to occur with a similar frequency as quasi-periodic indium fluctuations along [0001] observed within the 2D layer, to provide evidence that the resulting local strain relief at the steps acts as the trigger for a change of growth mode by elastic relaxation. This study demonstrates that misfit dislocation generation during the growth of wider InGaN shell layers can be avoided by using pre-etched GaN nanorods. Significantly, this enables the growth of absorption-based devices and light-emitting diodes with emissive layers wide enough to mitigate efficiency droop

    Structural and optical emission uniformity of m-plane InGaN single quantum wells in core-shell nanorods

    Get PDF
    Controlling the long-range homogeneity of core-shell InGaN/GaN layers is essential for their use in light-emitting devices. This paper demonstrates variations in optical emission energy as low as ~7 meV.µm-1 along the m-plane facets from core-shell InGaN/GaN single quantum wells as measured through high-resolution cathodoluminescence hyperspectral imaging. The layers were grown by metal organic vapor phase epitaxy on etched GaN nanorod arrays with a pitch of 2 µm. High-resolution transmission electron microscopy and spatially-resolved energy-dispersive X-ray spectroscopy measurements demonstrate a long-range InN-content and thickness homogeneity along the entire 1.2 μm length of the m-plane. Such homogeneous emission was found on the m-plane despite the observation of short range compositional fluctuations in the InGaN single quantum well. The ability to achieve this uniform optical emission from InGaN/GaN core-shell layers is critical to enable them to compete with and replace conventional planar light-emitting devices

    Evolution of the m-plane Quantum Well Morphology and Composition within a GaN/InGaN Core-Shell Structure

    Get PDF
    GaN/InGaN core–shell nanorods are promising for optoelectronic applications due to the absence of polarization-related electric fields on the sidewalls, a lower defect density, a larger emission volume, and strain relaxation at the free surfaces. The core–shell geometry allows the growth of thicker InGaN shell layers, which would improve the efficiency of light emitting diodes. However, the growth mode of such layers by metal organic vapor phase epitaxy is poorly understood. Through a combination of nanofabrication, epitaxial growth, and detailed characterization, this work reveals an evolution in the growth mode of InGaN epitaxial shells, from a two-dimensional (2D) growth mode to three-dimensional (3D) striated growth without additional line defect formation with increasing layer thickness. Measurements of the indium distribution show fluctuations along the &lt;10–10&gt; directions, with low and high indium composition associated with the 2D and 3D growth modes, respectively. Atomic steps at the GaN/InGaN core–shell interface were observed to occur with a similar frequency as quasi-periodic indium fluctuations along [0001] observed within the 2D layer, to provide evidence that the resulting local strain relief at the steps acts as the trigger for a change of growth mode by elastic relaxation. This study demonstrates that misfit dislocation generation during the growth of wider InGaN shell layers can be avoided by using pre-etched GaN nanorods. Significantly, this enables the growth of absorption-based devices and light-emitting diodes with emissive layers wide enough to mitigate efficiency droop
    corecore