295 research outputs found

    Schottky barrier and contact resistance of InSb nanowire field effect transistors

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    Understanding of the electrical contact properties of semiconductor nanowire (NW) field effect transistors (FETs) plays a crucial role in employing semiconducting NWs as building blocks for future nanoelectronic devices and in the study of fundamental physics problems. Here, we report on a study of the contact properties of Ti/Au, a widely used contact metal combination, to individual InSb NWs via both two-probe and four-probe transport measurements. We show that a Schottky barrier of height ΦSB20 meV\Phi_{\rm{SB}}\sim20\ \rm{meV} is present at the metal-InSb NW interfaces and its effective height is gate tunable. The contact resistance (RcR_{\rm{c}}) in the InSb NWFETs is also analyzed by magnetotransport measurements at low temperatures. It is found that RcR_{\rm{c}} at on-state exhibits a pronounced magnetic field dependent feature, namely it is increased strongly with increasing magnetic field after an onset field BcB_{\rm{c}}. A qualitative picture that takes into account magnetic depopulation of subbands in the NWs is provided to explain the observation. Our results provide a solid experimental evidence for the presence of a Schottky barrier at Ti/Au-InSb NW interfaces and can be used as a basis for design and fabrication of novel InSb NW based nanoelectronic devices and quantum devices.Comment: 12 pages, 4 figure

    Review of skin cancers terminology, etiology and treatment from ancient Persian medicine view point

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    Background: Skin cancers are the most prevalent type among the white with an increasing trend of incidence around the world and Iran. Scientific developments in diagnosing these cancers and using screening methods and utilizing treatment methods have contributed to the relative control of the cancer. Hence, it is necessary to consider other suggested approaches of complementary and traditional medicine to prevent and treat these cancers. Objective: The purpose of this review is to investigate the alternative remedies from the Persian Medicine; as a pioneer medical approach with an old history. Methods: In this review study, the medical textbooks of the golden era of Persian Medicine (9th to 19th centuries AD), i.e., the times of Razes and Avicenna, were explored and interesting opinions on skin malignancies were found. In addition, the phrase �skin cancers� was searched in databases like PubMed, Science Direct, Scopus, and Google Scholar. The gleaned data were analyzed and compared. Results: The ancient Persian scholars knew the cancers and were forerunners in the description, classified, etiology and treatment of skin cancers. This study explored interesting opinions like nutrition and black bile clearance on skin malignancies treatment, also found no contradictory views between the Persian and modern medicine on the topic of skin cancers. Conclusion: Paying attention to the neglected areas can makes useful theories and hypotheses fore achievement to new more effective and safe remedies. © 2020. Open access

    Critical Content Analysis of Narrative Version of Islamic Medicine

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    Background and Objective: The nature of Narrative version of Islamic medicine (NIM) is based on Quran and hadith, exclusive attention to Islamic narrative references and rejection of the strategies of other medical schools. This study was conducted to criticize NIM. Methods: In this qualitative study of content analysis, after collecting the opinions of 6 prominent scholars of NIM, the criticisms of these opinions were presented and categorized by three doctors specialized in Persian medicine, a cleric in the field of Islamic jurisprudence and a methodologist by holding expert panel meetings. Findings: Criticisms were raised based on three points of view. The intra-religious area including the routine of Ahl al-Bayt (The holy family of the Prophet Muhammad) in illness and the role of physicians, the place of reason and experience in Islamic sciences, differences in geographical areas, not mentioning the full history of patients and newly occurring diseases was brought up. From a medical point of view, the important points include lack of a research method to check the effectiveness of a medical narrative, lack of diagnostic aspects and an approach to screening. From the viewpoint of religious and social consequences, religious trauma resulting from lack of response to treatment attributed to Ahl al-Bayt, approach to other manifestations of Western civilization, ethical issue of producing, prescribing and selling drugs by a group and loss of life and money due to waste of time in cases with definitive or relative treatment was raised in other medical schools. Conclusion: Based on the results of this research, the introduction of this theory to society without sufficient investigations in the seminaries and universities of medical sciences may cause physical, mental and religious trauma at the individual and social level

    One health approach to tackle brucellosis: a systematic review

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    Background: Brucellosis is the most significant and common bacterial zoonosis and is recognized as a re-emerging and neglected disease. Tackling zoonosis is very important for the health and the economy. One Health is an approach characterized by the integration of human and animal health, plants, and ecosystems and encourages joining local, national, and global multidisciplinary efforts to achieve optimal levels of health and collaboration among different disciplines to address complex health problems. Objectives: The present study aimed to review published scientific literature related to the use of the One Health approach to tackle human brucellosis. Methods: Web of Science (WoS), PubMed, Scopus, The Cochrane Library, and Embase databases were searched from inception until 30 January 2020. The reference lists of all relevant papers were hand-searched. Two authors extracted data from published studies independently. The Joanna Briggs Institute tool was used to assess the quality of studies. Results: Of 2297 studies, 10 studies were deemed eligible, which were conducted between 2013 and 2019. Studies were performed in Uganda, Malta, Serbia, Greece, Mongolia, Azerbaijan, Israel, India, Ethiopia, and the USA. All studies suggested that brucellosis is still a major public health problem and that the most important aspect of the One Health approach is the interdependence of humans, ecosystems, and animals.Some studies have focused on livestock vaccination as the most effective way to prevent disease, and others have focused on the biology of Brucella infection and its transmission patterns. Some studies have pointed to the effectiveness of the One Health approach in all the phases of disease management as well as to its role in reducing health costs. Conclusion: The success of the approach depends on the willingness of the decision-makers to implement the necessary policies. Due to the heterogeneity of current practices, and organizations involved in One Health approach-based programs, it will be incomplete without proper planning. To better implement the approach, strategies should be appraised and disseminated by experts and relevant stakeholders. © 2020, The Author(s)

    Overview of hydatid disease in Iranian children

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    Background: Hydatid disease (HD) is still an important health hazard in the world. This disease is a parasitic infestation endemic in many sheep- and cattle-raising areas such as Iran. Objectives: This study aimed to review the clinical manifestations, laboratory aspects, imaging findings, and management of HD. Patients and Methods: Data were collected from the medical records of patients diagnosed with HD in eight referral hospitals in different provinces of Iran from 2001 to 2014. Results: Overall, 161 children at a mean age of 9.25 ± 3.37 years (age range = 1 - 15 years old) hospitalized with a definite diagnosis of the hydatid cyst between 2001 and 2014 were studied. The male-to-female ratio was 1.6:1. The most commonly involved organ was the lung (67.1), followed by the liver (44.1) and a combined liver and lung involvement was found in 15.5 of the patients. The cysts were found more frequently in the right lobe of the liver and lung than in the left lobe. The most frequent complaints were fever (35.4) and abdominal pain (31.7), and the most frequent sign was an abdominal mass in the liver involvement and cough in the lung involvement. There was a high eosinophil count (> 500/micL) in 41 of our cases. A high erythrocyte sedimentation rate (> 30) or positive C-reactive protein (based on the qualitative method) was found in 18.6 of the patients and leukocytosis > 15000/micL in 29.2 of the children. Ultrasonography was the main imaging test, with an accuracy rate of 96, and chest X-ray was helpful in 88.6 of the cases. Surgery was performed in 89 of the patients, and selective patients underwent percutaneous aspiration-injection-reaspiration drainage or medical treatment. Conclusions: The lung was the most commonly involved organ in the children recruited in the present study. Given the high probability of multiple organ involvement, we recommend that patients with HD be assessed via ultrasonography and chest X-ray. In endemic regions, unexplained eosinophilia should be considered as a parasitic disease like HD and its complications. © 2015 Pediartric Infections Research Center

    Estimation of radiation dose-reduction factor for cerium oxide nanoparticles in MRC-5 human lung fibroblastic cells and MCF-7 breast-cancer cells

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    In the current study, radiation dose-reduction factor (DRF) of nanoceria or cerium oxide nanoparticles (CONPs) in MRC-5 Human Lung Fibroblastic Cells and MCF-7 Breast-Cancer Cells was estimated. Characterization of CONPs was determined using scanner electron microscope (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and spectrophotometer. Then, six plans were designed with different radiation dose values on planning target value. The obtained MRC-5 and MCF-7 cells were treated with non-toxic concentrations of CONPs and then exposed. Finally, cell viability () of the cell lines was determined using MTT assay. The findings showed that CONPs have no significant radioprotective effect against 10 cGy radiation dose value. Nevertheless, 70 μM CONPs resulted in a significant radioprotection against 100, 200, 300, 400 and 500 cGy radiation dose values compared with the control group in MRC-5 cells. For all radiation dose values, mean cell viability () of MCF-7 had not increased significantly at the presence of nanoceria compared with control group. According to the findings, it was revealed that the use of CONPs have a significant radioprotective effect on normal lung cells, while they do not provide any protection for MCF-7 cancer cells. These properties can help to increase therapeutic ratio of radiotherapy. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group

    Association of screen time and physical activity with health-related quality of life in Iranian children and adolescents 11 Medical and Health Sciences 1117 Public Health and Health Services

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    Background: Health-related quality of life (HRQoL) is a multidimensional concept with significant effects and children and adolescence; while physical activity (PA) and screen time (ST) have been suggested as its probable predictors. Present study aims to investigate the association of PA, ST and their combination, with HRQoL in a nationally-representative sample of Iranian children and adolescents. Methods: As for the estimated sample size, 25,000 students aged 6-18 years were selected via multi-stage cluster sampling from 30 provinces of Iran. Sociodemographic data was obtained by using the questionnaire of the World Health Organization-Global school based student health survey (GSHS). Persian Pediatric Quality of Life inventory (PedsQL) and Physical Activity Questionnaire for the pediatric age group (PAQ-A) were applied for evaluating HRQoL and PA, respectively. PA scores 1-1.9 and 2-5 were respectively considered as low and high PA. The average duration of time spent on watching TV and leisure time computer use were considered as ST behaviors. ST of less than 2 h was considered low. Results: Out of 25,000 invited individuals, 23,043 students (mean age: 12.5) completed the study (response rate: 92.17). In linear regression models, ST duration had significant inverse association with total QoL (β:-0.49, p < 0.05). PA showed positive significant associations with HRQoL total score (β: 1.8, p < 0.05). Joint association of PA and ST revealed the strongest association of "high PA-low ST" category with total HRQoL (β: 2.2, p < 0.05); while "high PA-high ST" showed better total HRQoL score (β: 1.3) compared to "low PA-low ST" subgroup. Conclusion: Both PA and ST are significantly and independently associated with HRQoL in Iranian children and adolescents; while the adverse effect of prolonged ST could be diminished by a high PA. © 2019 The Author(s)

    The challenges of implementation of clinical governance in Iran: A meta-synthesis of qualitative studies

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    Background: Policy- and decision-makers seek to improve the quality of care in the health sector and therefore aim to improve quality through appropriate policies. Higher quality of care will satisfy service providers and the public, reduce costs, increase productivity, and lead to better organisational performance. Clinical governance is a method through which management can be improved and made more accountable, and leads to the provision of better quality of care. In November 2009, the Iranian Ministry of Health and Medical Education implemented new clinical guidelines to standardise and improve clinical services as well as to increase efficiency and reduce costs. The purpose of this study was to assess the challenges of implementing clinical governance through a meta-synthesis of qualitative studies published in Iran. Methods: Ten databases, including ISI/Web of Sciences, PubMed/MEDLINE, Embase, PsycINFO, the Cochrane Library, CINAHL, Scopus, Barakatns, MagIran and the Scientific Information Database, were searched between January 2009 and May 2018. The quality of the included studies was assessed using the Critical Appraisal Skills Programme tool. This study was reported according to the Enhancing Transparency in Reporting the Synthesis of Qualitative Research guidelines. Thematic synthesis was used to analyse the data. Results: Ten studies were selected and included based on the inclusion/exclusion criteria. In the first stage, 75 items emerged and were coded, and, following comparison and combination of the codes, 32 codes and 8 themes were finally extracted. These themes included health system structure, management, person-power, cultural factors, information and data, resources, education and evaluation. Conclusion: The findings of the study showed that there exist a variety of challenges for the implementation of clinical governance in Iran. To successfully implement a health policy, its infrastructure needs to be created. Using the views and support of stakeholders can ensure that a policy is well implemented. Trial registration: CRD42017079077. Dated October 10, 2017. © 2019 The Author(s)

    Crystal-Size Effects on Carbon Dioxide Capture of a Covalently Alkylamine-Tethered Metal-Organic Framework Constructed by a One-Step Self-Assembly

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    To enhance the carbon dioxide (CO2) uptake of metal-organic frameworks (MOFs), amine functionalization of their pore surfaces has been studied extensively. In general, amine-functionalized MOFs have been synthesized via post-synthetic modifications. Herein, we introduce a one-step construction of a MOF ([(NiLethylamine)(BPDC)]=MOFNH2; [NiLethylamine]2+=[Ni(C12H32N8)]2+; BPDC2-=4,4???-biphenyldicarboxylate) possessing covalently tethered alkylamine groups without post-synthetic modification. Two-amine groups per metal centre were introduced by this method. MOFNH2 showed enhanced CO2 uptake at elevated temperatures, attributed to active chemical interactions between the amine groups and the CO2 molecules. Due to the narrow channels of MOFNH2, the accessibility to the channel of CO2 is the limiting factor in its sorption behaviour. In this context, only crystal size reduction of MOFNH2 led to much faster and greater CO2 uptake at low pressures.open
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