Investigación del efecto de la temperatura de recocido sobre las propiedades ópticas de películas delgadas de CdSe

Introduction: CdSe is an important II–VI semiconducting material dueto its typical optical properties such as small direct band gap (1.7 eV) anda high refractive index and, thus, a major concern is focused on the investigation of optical properties of CdSe thin films which is important topromote the performances of the devices of solid -state such as SC (solar cells), thin film transistors, LED (light-emitting diodes), EBPL (electron–beam pumped lasers) and electroluminescent devices. In the presentwork, CdSe thin films were deposited by thermal evaporation method andthe results have been analysed and presented. Materials and Methods:CdSe thin films has been deposited on glass microscopic slides as substrates of (75×25×1 mm) under room temperature using PVD technique.CdSe blended powders gets evaporated and condensed on the substrate.The film thickness (t = 100 5 nm) which is measured using Michelsoninterferometry method. Transmission spectrum, from 200-1100 nm, arescanned using two beams UV–VIS Spectrophotometer (6850 UV/Vis.Spectrophotometer-JENWAY). The deposited films then were annealedat temperature range of (1500C to 3500C) under vacuum to have a stable phase of the material and prevent surface oxidization. Results andDiscussion: A transmittance spectrum of CdSe thin film is scanned overwavelength range 200 to 1100 nm using a (6850 UV/Vis. Spectrophotometer-JENWAY) at room temperature. The transmittance percentagebetween the as-deposited film and the annealed films change varies from(17.0%) to (47.0%). It is clearly seen that there is a shift toward higher energy (Blue Shift) in the transmittance spectrum. As annealing temperatureincreased the transmittance edge is shifted to the longer wavelength (i.e.,after annealing the CdSe films shows red shifts in their optical spectra).The band gap was found within the range 1.966-1.7536 eV for CdSe thinfilm. As annealing temperature increases, the Eg continuously decreases.Conclusions: CdSe thin films have been deposited using Physical VaporDeposition (PVD) Technique. It is found that the transmission for asdeposited films is (17%) and increases to (47%) as annealing temperature increases. Beside this the energy gap for as- deposited CdSe film is(1.966eV) and decreased from (1.909 eV) to (1.7536eV) as the annealingtemperature increases. There is a strong red shift in optical spectrum ofthe annealed CdSe films. There is a gradual shift of the annealed filmsthin film spectra as compared of bulk CdSe film

Availability of the Psychometric Properties of Holmes’ Test of Creative Personality: A Field Study on Secondary School Students in Sana’a- Republic of Yemen

هدفت هذه الدراسة إلى فحص الخصائص السيكومترية لاختبار هولمز للشخصية المبدعة على طلبة المرحلة الثانوية في العاصمة صنعاء، وتألفت عينة الدراسة من (514) طالباً وطالبة تم اختيارهم بطريقة عنقودية، وبعد تطبيق الاختبار على أفراد العينة تم التوصل إلى النتائج الآتية:  يتمتع الاختبار بصدق جيد، إذ تم التحقق من دلالات الصدق بأربع طرق: (أ) الصدق بالتحكيم؛ حيث تم حذف (12) فقرة بموجب ذلك، (ب) الصدق التلازمي مع تقديرات المعلمين؛ حيث تراوحت معاملاته بين (0.61) و (0.64) وجميعها دالة عند مستوى (0.01)، (ج) صدق البناء الداخلي، حيث تراوحت معاملات ارتباط الفقرات بالدرجة الكلية للاختبار بين (0.18) و (0.51) وجميعها دالة إحصائيا عند مستوى (0.01) ، (د) الصدق التمييزي، حيث كان الفرق بين متوسطي المجموعتين الطرفيتين دالاً إحصائياً عند مستوى (0.01) .يتمتع الاختبار بثبات جيد، إذ تم التحقق من ثلاثة أنواع من دلالات الثبات؛ فقد بلغ معامل الثبات بطريقة الإعادة (0.88)، وبطريقة التجزئة النصفية (0.93)، وبطريقة كرونباخ-ألفا (0.84).أظهرت النتائج وجود فرق دال إحصائياً عند مستوى (0.01) في أداء الطلبة على الاختبار تعزى لمتغير جنس الطلبة، ولصالح الإناث.  وفي ضوء النتائج أوصى الباحثان باستخدام الاختبار كأداة مقننة لاستكشاف الشخصية المبدعة لدى طلبة المرحلة الثانوية في أمانة العاصمة صنعاء. الكلمات المفتاحية: الخصائص السيكومترية، اختبار هولمز، الشخصية المبدعة.This study aimed at assessing the psychometric properties of Holmes’ Test of creative personality among secondary school students in Sana’a-Yemen. A cluster sample of (514) male and female students was  drawn. After applying the test on the sample the following results were reached: Four types of test validity were applied. A jury validity which resulted in deleting  (12) items of the test.  A concurrent validity of the test with teacher ratings ranged between (0.61) and (0.64) and all  were significant at . A construct validity was applied via the correlations between items and the total scores [ranged between 0.18 and (0.51); all were significant at ]. A discriminative validity was also applied; the difference between upper and lower group means was significant at . Three types of test reliability were drawn; test-retest r= (0.88), split-half r= (0.93), Cronbach-alpha r= (0.84). A significant difference in mean scores was found at between males and females in favor of females. Based on these results, the researchers recommended using Holmes’ test as a structured instrument to explore creative personality among secondary school students in Sana’a.  Keywords: Psychometric properties, Holmes’ test, Creative personality

Metamaterial Polarization Converter Analysis: Limits of Performance

In this paper we analyze the theoretical limits of a metamaterial converter that allows for linear-to- elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed level of the design generalization. Our analysis reveals that the maximal conversion efficiency for transmission through a single metamaterial layer is 50%, while the realistic re ection configuration can give the conversion efficiency up to 90%. We show that a double layer transmission converter and a single layer with a ground plane can have 100% polarization conversion efficiency. We tested our conclusions numerically reaching the designated limits of efficiency using a simple metamaterial design. Our general analysis provides useful guidelines for the metamaterial polarization converter design for virtually any frequency range of the electromagnetic waves.Comment: 10 pages, 11 figures, 2 table

BIM benefits and its influence on the BIM implementation in Malaysia

Building Information Modelling (BIM) implementation is considered a daunting reality because majority of the construction players don’t know the potential benefits of the technology. Awareness of BIM benefits and its implementation could significantly increase project productivity and performance. This study is aimed to determine the influence of BIM benefits from the Malaysian construction stakeholders’ perception towards its implementation. The study was carried out using survey questionnaire. Out of 590 questionnaires 268 were collected that represent a sample size of 346. Results revealed that most of the construction companies lack of awareness about BIM technology. The statistical analysis showed that productivity, time, cost, clashes, and communication are the most essential BIM benefits that concerned the participants. The driving factors of implementation, on the other hand, were identified as Trust, respect, commitment, early involvement, and knowledge. It is also found that there is a significant relationship between BIM benefits and its implementation

INVESTIGATION THE IMPACT OF DIFFERENT ANNEALING TEMPERATURES ON STRUCTURAL AND OPTICAL PROPERTIES OF BI-DOPED GETE (BI: 5 %) THIN FILMS FABRICATED BY PVD TECHNIQUE)

        The impact of different annealing temperatures on the Bi-doped GeTe thin films were investigated. The thin films have been prepared by using physical vapor deposition techniques (PVD). The Bismuth (Bi) is doped GeTe with ratio of 5%. Different characterizations techniques have been used to study the different properties of thin films with several annealing temperatures. It has been found that the film thickness decreases as the annealing temperature increases. The XRD patterns show that as-deposited and annealed Bi-doped GeTe films at 150°C,200°C, and 250°C were fully amorphous, while the film annealed at 100 °C was crystalline. FESEM image shows that the structure is amorphous with no grain appearing for the crystallite GeTe compound. Whereas the annealed thin films at 100°C are well-appeared crystallites of GeTe with an average size of (110.64 nm). The thin films are annealed at (150, 200, and 250)°C which reveals that the crystallite or grain is increased. An increase in the annealing temperature has been found to cause a significant shift in the absorption edge toward an extended wavelength and an overall reduction in transmittance. At a wavelength of 1100 nm, the transmittance dropped from 65.25% for as-deposited thin films to 32.57% for annealed thin films at 250 °C. Furthermore, when the annealing temperature rises from 100°C to 250°C, the optical band gap reduces from 0.95 eV to 0.42 eV

Impact of The Protective Renin-Angiotensin System (RAS) on The Vasoreparative Function of CD34+ CACs in Diabetic Retinopathy

Purpose: In diabetes, the impaired vasoreparative function of Circulating Angiogenic Cells (CACs) is believed to contribute to the progression of diabetic retinopathy (DR). Accumulating evidence suggests that the protective arm of renin-angiotensin system (RAS) ACE2 Angiotensin-(1-7) Mas plays an important role in restoring the function of diabetic CACs. We examined the protective RAS in CACs in diabetic individuals with different stages of retinopathy. Methods: Study subjects (n43) were recruited as controls or diabetics with either no DR, mild non-proliferative DR (NPDR), moderate NPDR, severe NPDR or proliferative DR (PDR). Fundus photography and fluorescein angiograms were analyzed using Vessel Generation Analysis (VESGEN) software in a cohort of subjects. CD34+ CACs were isolated from peripheral blood of diabetics and control subjects. RAS gene expressions in CACs were measured by qPCR. The vasoreparative function of CACs was assessed by migration ability toward CXCL12 using the QCM 5M 96-well chemotaxis cell migration assay. Results: ACE2 gene is a key enzyme converting the deleterious Angiotensin II to the beneficial Angiotensin-(1-7). ACE2 expression in CACs from diabetic subjects without DR was increased compared to controls, suggestive of compensation (p0.0437). The expression of Mas (Angiotensin-(1-7) receptor) in CACs was also increased in diabetics without DR, while was reduced in NPDR compared to controls (p0.0002), indicating a possible loss of compensation of the protective RAS at this stage of DR. The presence of even mild NPDR was associated with CD34+ CAC migratory dysfunction. When pretreating CACs of DR subjects with Angiotensin-(1-7), migratory ability to a chemoattractant CXCL12 was restored (p0.0008). By VESGEN analysis, an increase in small vessel density was observed in NPDR subjects when compared with the controls. Conclusions: These data suggest the protective RAS axis within diabetic CACs may help maintain their vasoreparative potential. The VESGEN analysis supports the presence of retinal repair in small vessels. The loss of the protective arm of RAS may predict the progression of DR

Extended Malaria Parasite Clearance Time in African Children Following Artemisinincombination Therapy Enhances Transmission\ud to Anopheles Mosquitoes

Artemisinin resistance was recently shown to have spread or emerged on the Thailand/Myanmar border. Evidence is accumulating that the parasite clearance time after artemisinin-based combination therapy (ACT) is increasing in settings in Asia and Africa. It is currently unknown if an extended parasite clearance time after ACTs has consequences for the individual patient or confers a higher malaria transmission potential. 298 children in Mbita, Western Kenya, with uncomplicated falciparum malaria were randomized to artemether-lumefantrine (AL, n = 153) ordihydroartemisinin-piperaquine (DP, n = 145). Parasite carriage post-treatment was determined by microscopy and qPCR, gametocyte carriage by quantitative nucleic acid sequence based amplication. Infectiousness to mosquitoes was determined by mosquito membrane feeding assays. Both drugs were efficacious as judged by standard trial outcomes. Sub-patent residual parasitaemia on day 3 was detected by qPCR in 36.11% (95% CI 25.11 - 48.29) of children treated with AL, and in 30.16% (95% CI 19.23 - 43.02) of children treated with DP. After adjustment for age, treatment arm and enrolment parasite density, children with an extended parasite clearance time were significantly more likely to have microscopically detected recurrent parasitaemia during follow-up (Odds Ratio: 19.51, 95% CI 5.24 - 72.71, p < 0.001). Children with an extended parasite clearance time were also more likely to be infectious to mosquitoes (Odds Ratio 2.76; 95% CI 1.14 - 6.67, p = 0.02) and gave rise to a higher oocyst load in mosquitoes (Incidence Rate Ratio 2.80, 95% CI 1.49 - 5.24, p = 0.001). Our findings indicate that an extended parasite clearance time after ACTs has consequences for the individual patient and for the population at large due to higher transmission potential. The high prevalence of residual subpatent parasitaemia after treatment may be due to novel parasite genotypes with reduced drug sensitivity, inadequate population-level immunity, or the higher sensitivity of qPCR for detection of persisting parasites.\u

Gastrointestinal stromal tumor of the anal canal: an unusual presentation

BACKGROUND: Gastrointestinal stromal tumors (GIST) of the stomach are the most frequent followed by those of the intestinal tract, while colon and rectum represent rare sites. GIST of the anal canal are extremely rare. They have been studied along with GIST of the rectum, as a single entity, and along with them they represent 5% of GIST. GIST arising from the anal canal account for only 2%–8% of the anorectal GIST. Thus anal GIST must be considered an exceptional case. CASE PRESENTATION: A 78-year-old man was referred to our Institution for an anal mass, in absence of any symptom. The patient was treated by local excision. An histological diagnosis of a low grade GIST was made. No further treatment was necessary. No local recurrence of distant metastases were found at follow-up. CONCLUSION: At the moment, only ten cases of c-kit positive anal GIST are reported in the literature. These few data are not sufficient to establish a widely accepted approach for this neoplasia. We recommend to perform an initial local excision, to define the risk of aggressive behavior and the resection margins and proceed to a more aggressive treatment, if the GIST belongs to high or very high risk group. The role of adjuvant therapy is still uncertain. Although inhibitors of tyrosine-kinase receptor needs further studies before their routine use, their role in case of distant or local recurrence has been accepted. Patients' close follow up is mandatory to disclose as soon as possible local recurrences or metastases

Cellular Angiofibroma of Oral Mucosa: Report of Two Cases

Cellular angiofibroma is a benign vascular neoplasm that typically arises in the vulva, perineal, and paratesticular region. Microscopically the lesions exhibit multiple small, non-dilated capillary channels, many of which contain erythrocytes. The endothelial lining cells are prominent, with monomorphic oval nuclei. Interposed among the vessels are both delicate and mature collagen fibers with fibroblastic hypercellularity that is variable in older lesions where sclerosis is prominent. The lesions usually do not recur following simple excision. Recent evidence indicates that cellular angiofibromas may be cytogenetically related to spindle cell lipoma. This represents the first reported instances of cellular angiofibroma in the oral cavity

Loss of Angiotensin-Converting Enzyme 2 Exacerbates Diabetic Retinopathy by Promoting Bone Marrow Dysfunction

Angiotensin-converting enzyme 2 (ACE2) is the primary enzyme of the vasoprotective axis of the renin angiotensin system (RAS). We tested the hypothesis that loss of ACE2 would exacerbate diabetic retinopathy by promoting bone marrow dysfunction. ACE2-/y were crossed with Akita mice, a model of type 1 diabetes. When comparing the bone marrow of the ACE2-/y-Akita mice to that of Akita mice, we observed a reduction of both short-term and long-term repopulating hematopoietic stem cells, a shift of hematopoiesis towards myelopoiesis, and an impairment of lineage-c-kit+ hematopoietic stem/progenitor cell (HS/PC) migration and proliferation. Migratory and proliferative dysfunction of these cells was corrected by exposure to angiotensin-1–7 (Ang-1–7), the protective peptide generated by ACE2. Over the duration of diabetes examined, ACE2 deficiency led to progressive reduction in electrical responses assessed by electroretinography and to increases in neural infarcts observed by fundus photography. Compared to Akita mice, ACE2-/y-Akita at 9-months of diabetes showed an increased number of acellular capillaries indicative of more severe diabetic retinopathy. In diabetic and control human subjects, CD34+ cells, a key bone marrow HS/PC population, were assessed for changes in mRNA levels for MAS, the receptor for Ang-1–7. Levels were highest in CD34+ cells from diabetics without retinopathy. Higher serum Ang-1–7 levels predicted protection from development of retinopathy in diabetics. Treatment with Ang-1–7 or alamandine restored the impaired migration function of CD34+ cells from subjects with retinopathy. These data support that activation of the protective RAS within HS/PCs may represent a therapeutic strategy for prevention of diabetic retinopathy