An investigation on effectiveness of temperature treatment for fluorine-based reactive plasma jet machining of N-BK7®

In this study, a fluorine-based reactive plasma jet is investigated as a promising tool for ultraprecise surface machining of N-BK7®. Plasma-generated particles react with an N-BK7 surface to create volatile and nonvolatile compounds. The desorption of volatile compounds results in an etched surface, whereas nonvolatile compounds form a residual layer in the etched area, causing unpredictable effects on the etching rate. Surface temperature treatment is proposed to improve the machining procedure with respect to deterministic material removal, leading to predictable results. It is shown that, at an elevated surface temperature, the residual layer properties are modified in favor of improved etching performance. The etching behavior of N-BK7 is compared with fused silica to verify the optimality of the obtained results

A novel Deal–Grove-inspired model for fluorine-based plasma jet etching of borosilicate crown optical glass

The Deal–Grove model is a state-of-the-art approach proposed for describing the thermal oxidation of silicon and the oxide thickness over time. In this study, the Deal–Grove concept provided the inspiration for a mathematical model for simulating plasma jet-based dry etching process of borosilicate crown glass (N-BK7®). The whole process is contained in two so-called Deal–Grove parameters, which are extracted from experimental data including local etching depth and surface temperature distribution. The proposed model is extended for the evolution of dynamic etch profiles, and the obtained results are validated experimentally. By establishing such a model, it is possible to predict the effect of the residual layer and surface temperature on the evolution of local etching depths over dwell time

Development of a model for ultra-precise surface machining of N-BK7® using microwave-driven reactive plasma jet machining

In this paper, extensive studies are conducted as key to overcoming several challenging limitations in applying fluorine-based reactive plasma jet machining (PJM) to surface machining of N-BK7®, particularly regarding the manufacture of freeform optical elements. The chemical composition and lateral distributions of the residual layer are evaluated by X-ray photoelectron spectroscopy and scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis aiming at clarifying the exact chemical kinetics between plasma generated active particles and the N-BK7 surface atoms. Subsequently, a model is developed by performing static etchings to consider the time-varying nonlinearity of the material removal rate and estimate the local etching rate function. Finally, the derived model is extended into the dynamic machining process, and the outcomes are compared with the experimental results

Extracting the innovation policies for Iran based on the approximation of policy implications for comparative economic doctrines

Due to many differences in presumptions and theoretical foundations within neoclassical and evolutionary economics, policy-makers are always confronted with the dilemma of selecting one of these two central models for technology and innovation policy. In light of widely institutionalised ineffectiveness in the field of market and systematic coordination – in Iran as well many other countries – the present investigation presumes that reliance on any of the above doctrines alone is ineffective. An intermediate concept of policy rationales to achieve a comparative structure of policy implications is proposed. Policy rationales (in innovation and technological policy) for neoclassical and evolutionary economics were derived based on a thematic analysis. A spectrum of policy implications of both doctrines was designed and completed in the form of a questionnaire for, together with theoretical foundations and policy rationales by specialists of the field of innovative and technological policy in Iran. Given the institutional conditions and structural frameworks which actually exist, and in spite of wide dissimilarities within the theoretical foundations of neoclassical and evolutionary economics, Clustering of respondents and subsequent test trials show that policy implications of the economics doctrines in the field of innovative and technological policy in Iran are complementary and convergent

Equine Adipose-Derived Mesenchymal Stem Cells: Phenotype and Growth Characteristics, Gene Expression Profile and Differentiation Potentials

Objective: Because of the therapeutic application of stem cells (SCs), isolation and characterization of different types of SCs, especially mesenchymal stem cells (MSCs), have gained considerable attention in recent studies. Adipose tissue is an abundant and accessible source of MSCs which can be used for tissue engineering and in particular for treatment of musculoskeletal disorders. This study was aimed to isolate and culture equine adipose-derived MSCs (AT-MSCs) from little amounts of fat tissue samples and determine some of their biological characteristics. Materials and Methods: In this descriptive study, only 3-5 grams of fat tissue were collected from three crossbred mares. Immediately, cells were isolated by mechanical means and enzymatic digestion and were cultured in optimized conditions until passage 3 (P3). The cells at P3 were evaluated for proliferative capacities, expression of specific markers, and osteogenic, chondrogenic and adipogenic differentiation potentials. Results: Results showed that the isolated cells were plastic adherent with a fibroblast-like phenotype. AT-MSCs exhibited expression of mesenchymal cluster of differentiation (CD) markers (CD29, CD44 and CD90) and not major histocompatibility complex II (MHC-II) and CD34 (hematopoietic marker). Cellular differentiation assays demonstrated the chondrogenic, adipogenic and osteogenic potential of the isolated cells. Conclusion: Taken together, our findings reveal that equine MSCs can be obtained easily from little amounts of fat tissue which can be used in the future for regenerative purposes in veterinary medicine

Developing and validating a measurement tool to self-report perceived barriers in substance use treatment : The substance use treatment barriers questionnaire (SUTBQ)

Background Substance using often cause a wide range of social, health, and psychological problems. This study aimed to develop and validate a questionnaire of barriers of treatment in substance users. Methods In this cross-sectional study, the initial questionnaire was designed based on the evaluation of previous studies. The preliminary tool including 35 Likert-scaled items. After assuring the face validity of the questionnaire, 13 experts’ opinions were obtained for assessing or improving the content validity. The reliability was investigated by internal consistency methods using Cronbach’s alpha. For measuring the structural validity, the exploratory factor analysis was performed to determine the dimensionality of the questionnaire using principal components extraction and Varimax rotation. Results The preliminary questionnaire consisted of 35 items. After completing the face validity and summarizing the experts’ suggestions, 8 items were removed. By calculating the content validity ratio and coefficient, 11 questions were deleted. The internal consistency was calculated to be 0.84 using Cronbach’s alpha. In the last stage and according to the results of the factor analysis, three factors fear of or unawareness of treatment, doubt or inefficiency, and social stigma were identified from the 10-items questionnaire, which explained 67.34% of the total variance. Conclusion Considering the necessity of using a validated tool for planning and evaluating effective interventions on people who use substance is inevitable. The Substance use Treatment Barriers Questionnaire is designed with 10 items and 3 dimensions, which has appropriate validity and reliability and can be used to determine the obstacles for treatment or factors that lead to discontinuing treatment

Development of a model for ultra‐precise surface machining of N‐BK7® using microwave‐driven reactive plasma jet machining

In this paper, extensive studies are conducted as key to overcoming several challenging limitations in applying fluorine-based reactive plasma jet machining (PJM) to surface machining of N-BK7®, particularly regarding the manufacture of freeform optical elements. The chemical composition and lateral distributions of the residual layer are evaluated by X-ray photoelectron spectroscopy and scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis aiming at clarifying the exact chemical kinetics between plasma generated active particles and the N-BK7 surface atoms. Subsequently, a model is developed by performing static etchings to consider the time-varying nonlinearity of the material removal rate and estimate the local etching rate function. Finally, the derived model is extended into the dynamic machining process, and the outcomes are compared with the experimental results

Mini Mental State Examination (MMSE) in First Episode of Psychosis

"nObjective: Neurocognitive deficits are now recognized as part of the fundamental disturbances and are a major determinant of functional outcome in psychosis. A cross-sectional association between cognitive deficits and poor social and occupational outcomes has been demonstrated; and treatment of cognitive impairment at the time of the first episode may have the potential to change functional outcomes of the illness. We conducted this study to evaluate cognitive function in first episode of psychosis by the Mini Mental State Examination (MMSE). "nMethod: Sixty two patients with first episode of psychosis were selected and underwent psychiatric interview and took MMSE test. Statistical analysis was done using SPSS-18 software. "nResults: According to MMSE scale, 47 patients (75.8%) showed definite cognitive impairment, 8(12.9%) showed possible impairment ,and 7(11.3%) showed no cognitive impairment. According to MMSE subscale, registration (69.4%) and recall (77.3%) were the most impaired cognitive areas.  "nConclusions:  The results of the current study indicate significant cognitive impairment in patients with first episode of psychosis. We recommend future studies with larger sample size and control group for further evaluation of cognitive function as early treatment of cognitive impairments may have important implications in the course of illness

Advances in precision freeform manufacturing by plasma jet machining -INVITED

Atmospheric pressure plasma jet machining technology provides a flexible and efficient way to fabricate precise freeform optics. Due to the pure chemical material removal mechanism based on a dry etching process using fluorine containing gas, the choice of materials that can be treated is limited. Fused silica, Si, SiC or ULE® are easy to machine since the etching products formed are solely volatile. Recently, plasma jet machining has been also adopted to treat optical glasses like N-BK7® which contain amongst others alkali metals that form a solid residual layer during etching. In the paper a new approach to apply deterministic plasma jet etching on optical glass coping with complex etch characteristics caused by the residual layer is introduced

Advances in precision freeform manufacturing by plasma jet machining -INVITED

Atmospheric pressure plasma jet machining technology provides a flexible and efficient way to fabricate precise freeform optics. Due to the pure chemical material removal mechanism based on a dry etching process using fluorine containing gas, the choice of materials that can be treated is limited. Fused silica, Si, SiC or ULE® are easy to machine since the etching products formed are solely volatile. Recently, plasma jet machining has been also adopted to treat optical glasses like N-BK7® which contain amongst others alkali metals that form a solid residual layer during etching. In the paper a new approach to apply deterministic plasma jet etching on optical glass coping with complex etch characteristics caused by the residual layer is introduced