Micro- and nanoparticle generation during nanosecond laser ablation: correlation between mass and optical emissions

The particulate emission during nanosecond ablation of gold targets was investigated at various fluences (10-100 Jcm(-2)) and vacuum levels (0.05-750 Torr). Atomic emission spectra were acquired during the ablation process and post-mortem characterization of particle spatial distribution was performed using scanning electron microscopy. The discussion of the results in the context of existing theoretical models permitted the identification of four distinct mass removal mechanisms. While the presence, shape and intensity of atomic emission lines is a telltale of the nanoparticle formation process, the fluctuations of the emission signal over a number of laser shots was linked to the production of microscopic debris

A Comparative Study of Power Distance of English Teachers and Non-English Teachers in Classroom Interaction in Iranian High Schools

This is the final version. Available on open access from Richtmann Publishing via the DOI in this recordSince cultural factors play a crucial role in creating behavioral patterns, investigating the relationship between English teachers and students can be a good index for discovering the level of power distance in the classroom environment with different cultures manifesting in their interactions. The current study has attempted to compare female high school students' viewpoints towards English teachers and non-English teachers in the Iran context to discover the difference in power distance between English and non-English teachers and their students. To this end, the present research was conducted in 3 high schools for females with female teachers, and the data was gathered through a five-item Likert scale questionnaire investigating students' viewpoints towards five main elements: Acceptability, Respect, Teaching method, behavioral patterns, and Friendship. The findings revealed a high power distance between English teachers and their students in an English class interaction than non-English teachers such as science teachers, math teachers, physics teachers, chemistry teachers, and art teachers and their students. In turn, the results implied positive viewpoints towards English teachers. Regarding four factors, Acceptability, Respect, Teaching method, and Behavior, there is a significant difference between the viewpoints towards English and non-English teachers. On the other hand, there is no significant difference between the two variables in terms of friendship

Prevalence of Soft Tissue Calcification in Panoramic Radiographs in Northern of Iran

BACKGROUND AND OBJECTIVE: Soft tissue calcification is a relatively common issue in panoramic radiography. Some of these calcifications may have non-specific clinical symptoms as feeling of foreign body, dysphagia, otalgia and non-reflective cough. Therefore, for correct diagnosis and avoiding incorrect and excess treatments it’s necessary to have information about prevalence of these calcifications in regional populations. This study aimed to determine the prevalence of soft tissue calcification in panoramic radiographs in a selected population in northern Iran. METHODS: In this cross sectional study, panoramic radiographs of 5000 patients referring to Oral & Maxillofacial radiology department of Babol dental school from 2014 to 2017 were examined. Radiographs were evaluated for the presence of any calcification, and their prevalence and their relationship with age were evaluated in two groups of under and over 40 years of age and gender. FINDING: The prevalence of the observed soft tissue calcifications including calcification of stylohyoid ligands was 484 cases (9.7%), tonsilolith 52 cases (1%), calcification of lymph nodes 9 cases (0.2%), calcification of carotid artery 22 cases (0.4%) and thyroid cartilage calcification was 17 cases (0.3%). No cases of rhinolith, antrolith, sialolith and phlebolitis were found. The amount of tonsilolith (34 to 18 cases) and lymph node calcification (7 versus 2 cases) were significantly higher in men. (p=0.002 and p =0.048). Also, the prevalence of calcification of stylohyoid ligament (290 versus 194 cases) (p=0.001), tonsilolith (13% vs. 39 cases) (p=0.001), calcification of carotid artery (18 versus 4) (p=0.001), and thyroid (14 versus 3) (p=0.003) were significantly relevant with age. CONCLUSION: The results of this study showed that soft tissue calcifications are prevalent and the most common is stylohyoid ligament calcification

Open-atmosphere structural depth profiling of multilayer samples of photovoltaic interest using laser-induced plasma spectrometry

The present work aims to assess Laser-Induced Plasma Spectrometry (LIPS) as a tool for the characterization of photovoltaic materials. Despite being a well-established technique with applications to many scientific and industrial fields, so far LIPS is little known to the photovoltaic scientific community. The technique allows the rapid characterization of layered samples without sample preparation, in open atmosphere and in real time. In this paper, we assess LIPS ability for the determination of elements that are difficult to analyze by other broadly used techniques, or for producing analytical information from very low-concentration elements. The results of the LIPS characterization of two different samples are presented: 1) a 90 nm, Al-doped ZnO layer deposited on a Si substrate by RF sputtering and 2) a Te-doped GaInP layer grown on GaAs by Metalorganic Vapor Phase Epitaxy. For both cases, the depth profile of the constituent and dopant elements is reported along with details of the experimental setup and the optimization of key parameters. It is remarkable that the longest time of analysis was ∼10 s, what, in conjunction with the other characteristics mentioned, makes of LIPS an appealing technique for rapid screening or quality control whether at the lab or at the production line

Presenting a Model Regarding the Effect of Ethical Sensitivity and Its Associated Components on the Quality of Research among Academic Personnel

Background and Objective: Ethical sensitivity is one of the criteria regarding the professional competence of researchers, which affects the ethical performance of the researcher. Since compliance with the principles and rules of ethics is an effective factor in providing high quality research results, the present study was conducted to investigate the ethical sensitivity and its associated components on the quality of research among academic personnel of universities of medical sciences in metropolitan area No. 1 in Iran. Methods: This cross-sectional study was conducted on 320 academic personnel of universities of medical sciences in metropolitan area No. 1 (Guilan, Mazandaran, Golestan, Babol, Shahrud, and Semnan) who were selected by stratified random sampling. Data were collected using ethical sensitivity and research quality questionnaires. The ethical sensitivity questionnaire includes 50 questions and two dimensions of "functional and individual", each of which includes 4 fields. The researcher-made questionnaire of research quality includes 31 questions and 4 fields. The questionnaires were rated from 1 to 5 according to Likert scale. Ethical sensitivity was compared between researchers based on work experience, academic degree and gender. Then, the effect of each component of ethical sensitivity on the quality of the research was evaluated. Findings: Out of 320 studied samples, 223 were male (69.7%) and 97 were female (30.3%). In people with experience of less than 10 years, the mean score of honesty was 15.74±3.21, ethical behavior was 30.50±5.74, accountability was 33.81±5.64, decision-making was 23.62±4.28, and interpersonal communication was 18.66±3.56, indicating higher values compared to people with an experience of more than 10 years (p<0.01). Among the dimensions of ethical sensitivity, the dimensions of honesty and discipline showed positive and significant effects on the quality of research. However, the effect of respect for the client, ethical behavior, professional knowledge, accountability, decision-making and interpersonal communication was not statistically significant despite the effect on the quality of the research. Discipline had the greatest effect on research quality (β=0.293). The R2 value (0.489) shows that about 49% of the variance of the research quality score is explained by the dimensions of ethical sensitivity. Ethical sensitivity with a standard coefficient of 7.758 had an effect on the quality of research. Conclusion: The results of the present study showed that ethical sensitivity, especially the dimensions of honesty and discipline, has an effect on the quality of research

XPS as Characterization Tool for PV: From the Substrate to Complete III-V Multijunction Solar Cells

This contribution aims to illustrate the potential of the X-ray photoelectron spectroscopy (XPS) technique as a tool to analyze different parts of a solar cell (surface state, heterointerfaces, profile composition of ohmic contacts, etc). Here, the analysis is specifically applied to III-V multijunction solar cells used in concentrator systems. The information provided from such XPS analysis has helped to understand the physico-chemical nature of these surfaces and interfaces, and thus has guided the technological process in order to improve the solar cell performance

Analysis of the surface state of epi-ready Ge wafers

The surface state of Ge epi-ready wafers (such as those used on III-V multijunction solar cells) supplied by two different vendors has been studied using X-ray photoemission spectroscopy. Our experimental results show that the oxide layer on the wafer surface is formed by GeO and GeO2. This oxide layer thickness differs among wafers coming from different suppliers. Besides, several contaminants appear on the wafer surfaces, carbon and probably chlorine being common to every wafer, irrespective of its origin. Wafers from one of the vendors show the presence of carbonates at their surfaces. On such wafers, traces of potassium seem to be present too

Case study in failure analysis of accelerated life tests (ALT) on III-V commercial triple-junction concentrator solar cells

In this work the failure analysis carried out in III-V concentrator multijunction solar cells after a temperature accelerated life test is presented. All the failures appeared have been catastrophic since all the solar cells turned into low shunt resistances. A case study in failure analysis based on characterization by optical microscope, SEM, EDX, EQE and XPS is presented in this paper, revealing metal deterioration in the bus bar and fingers as well as cracks in the semiconductor structure beneath or next to the bus bar. In fact, in regions far from the bus bar the semiconductor structure seems not to be damaged. SEM images have dismissed the presence of metal spikes inside the solar cell structure. Therefore, we think that for these particular solar cells, failures appear mainly as a consequence of a deficient electrolytic growth of the front metallization which also results in failures in the semiconductor structure close to the bus bars

Angiotensin-converting enzyme genotype and late respiratory complications of mustard gas exposure

<p>Abstract</p> <p>Background</p> <p>Exposure to mustard gas frequently results in long-term respiratory complications. However the factors which drive the development and progression of these complications remain unclear. The Renin Angiotensin System (RAS) has been implicated in lung inflammatory and fibrotic responses. Genetic variation within the gene coding for the Angiotensin Converting Enzyme (ACE), specifically the Insertion/Deletion polymorphism (I/D), is associated with variable levels of ACE and with the severity of several acute and chronic respiratory diseases. We hypothesized that the ACE genotype might influence the severity of late respiratory complications of mustard gas exposure.</p> <p>Methods</p> <p>208 Kurdish patients who had suffered high exposure to mustard gas, as defined by cutaneous lesions at initial assessment, in Sardasht, Iran on June 29 1987, underwent clinical examination, spirometric evaluation and ACE Insertion/Deletion genotyping in September 2005.</p> <p>Results</p> <p>ACE genotype was determined in 207 subjects. As a continuous variable, FEV₁% predicted tended to be higher in association with the D allele 68.03 ± 20.5%, 69.4 ± 21.4% and 74.8 ± 20.1% for II, ID and DD genotypes respectively. Median FEV₁% predicted was 73 and this was taken as a cut off between groups defined as having better or worse lung function. The ACE DD genotype was overrepresented in the better spirometry group (Chi²4.9 p = 0.03). Increasing age at the time of exposure was associated with reduced FEV₁%predicted (p = 0.001), whereas gender was not (p = 0.43).</p> <p>Conclusion</p> <p>The ACE D allele is associated with higher FEV₁% predicted when assessed 18 years after high exposure to mustard gas.</p

Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout. Methods The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function. Findings Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function. Interpretation Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI