Delamination of polyimide in hydrofluoric acid

Wet etching is a critical fabrication step for the mass production of micro and nanoelectronic devices. However, when an extremely corrosive acid such as hydrofluoric (HF) acid are used during etching, an undesirable damage might occur if the device includes a material that is not compatible with the acid. Polyimide thin films can serve as sacrificial/structural layers to fabricate freestanding or flexible devices. The importance of polyimide in microelectronics is due to its relatively low stress and compatibility with standard micromachining processes. In this work, a fast delamination process of a 4-μm-thin film of polyimide from a silicon substrate has been demonstrated. The films’ detachment has been performed using a wet-based etchant of HF acid. Specifically, the effect of HF concentration on the delamination time required to detach the polyimide film from the substrate has been investigated. This study is intended to provide the information on the compatibility of using polyimide films with HF, which can help in the design and fabrication of polyimide-based devices

Plastic surgery lockdown learning during coronavirus disease 2019: are adaptations in education here to stay?

The novel coronavirus disease 2019 has had a major impact on human life and livelihood. The unprecedented challenges have expanded beyond just social and work life, and have grown to impact resident education. In this article, we review the structure of plastic surgery education before the pandemic, the different online learning opportunities for self-directed learning. A summary of the range of platforms and approaches of online remote access delivery of conferences and education that emerged or expanded as a result of the crisis has been reported. This article highlighted the rapid initiatives and efforts of programs and national and international societies to support continuing medical education in conjunction with the guidelines to “shelter at home” and maintain social distancing, and possible future for expanding the reach of online academic initiatives, in addition to the role of developing virtual technologies. The coronavirus disease 2019 crisis has created an opportunity to analyze and advance online learning options to overcome the associated challenges and continue as a reliable platform even following the resolution of the social distancing requirements

Studying the Physical Properties of Hma with Recycled Aggregate Subjected to Moisture

تصنع الخلطات الاسفلتية الحارة HMA  من مواد معينة ذات حساسية لوجود المياه في التبليط الاسفلتي الذي يمنع العجينة من الالتصاق بالركام . ولكون العجينة هي الغراء الذي تمسك الخلطة مع بعضها , لذا فان  الفشل الانشائي المتوقع بالتبليط سيكون سريع من جراء ضعف الالتصاق بين العجينة والركام او ما يسمى بالانفصال  stripping الذي يوجب استخدام مضافات معينة لتجنبه ك الجير المطفأ او أي مواد كيمياوية مضادة للانفصال anti-stripping.  وعليه اجريت هذه الدراسة لفحص وقياس مقاومة انواع مختلفة من الخلطات الاسفلتية ذات ركام معاد تدويره عند تعريضها لفترات تشبع بالرطوبة بالإضافة الى فحص مغزى استخدام المضادات للانفصال كمضافات . تم  في هذا البحث تعريض ثلاثة انواع من الخلطات الاسفلتية , واحدة 60% من ركامها معاد من خلطة اسفلتية واخرى 60% من ركامها معاد من خلطة خرسانية  والخلطة الثالثة مستخدمة الشمع كمضاف وبنسبة 10% من وزن الاسفلت , للتغريق بالماء بمدد مختلفة تمثلت ب( 3, 7, 15, 28 ) يوم , كما  اجريت فحوصات مختبرية متعددة عليها ومقارنة النتائج مع خلطة اسفلتية قياسية عرضت لنفس الظروف . تم اجراء( فحص مارشال للثبات والزحف ), الكثافة , مقاومة الشد الغير مباشرة , مقاومة الانضغاط ، فحص التحسس للحرارة , فحص قوة المرونة . كان التحري موفقا حيث اعطى نتائج قيمة تبين تحسن الخلطة الاسفلتية في مقاومتها للرطوبة عند استخدام ركام معاد من خلطات سابقة واثبات دور الشمع الفعال في زيادة تللك المقاومة وتحسين خواص الخلطة الاسفلتية.As being exposed to water that exists on asphalt road, HMA that is created by utilizing a certain resources may require to be made strong due to the capability of that water to stop the covering to be attached to the aggregate, consequently, asphalt road layers will not be held jointly, this will have a negative influence on the asphalt that will be damaged quickly. Such phenomenon is known as "the erosion", which requires to be dealt with by, for example, improving asphalt layers by means of specific resources that assist in existence of water. Different ways in this work are employed to calculate the strength of various mixes via using used aggregate that is exposed to  saturation times, similarly, the importance of exploiting the anti-stripping as chemical addition is determined. Three kinds of HMA were exposed in the current study, 60% of the first kind were made of used aggregate taking from crushed pavement, and 60% of the second kind were taking from using aggregate that is part of concrete mix, while the third mixture has 10% of wax used as an addition by pavement weight. These mixtures were soaked in water bath of 25o C for various intervals of time that are (3, 7, 15, 28) days. Many investigations examinations had been as well executed, and then the outcomes were contrasted against standard pavement blend subjected to similar circumstances. Number of examinations were adopted in this study, these are (Marshall Stability and flow), mass thickness, roundabout elasticity, compressive quality, affectability to temperature, flexible modulus. The study achieved a good success as it makes important outcomes, the enhanced pavement showed strength against moisture damage while taking advantage of used aggregate of preceding blends, on other hand, the wax has affective role in raising these strengths in addition to develop the characteristics of HMA.&nbsp

University of Vermont Community Tobacco Use and Attitudes Survey

Introduction: Smoking remains an important public health issue in U.S. Colleges. 17.3% of U.S. smokers are 18-24 years old. 28% of U.S. college students began smoking at age 19 or older. Currently 1,104 U.S. Colleges have adopted Tobacco-Free policies.https://scholarworks.uvm.edu/comphp_gallery/1216/thumbnail.jp

Thermodynamic properties of an interacting hard-sphere Bose gas in a trap using the static fluctuation approximation

A hard-sphere (HS) Bose gas in a trap is investigated at finite temperatures in the weakly-interacting regime and its thermodynamic properties are evaluated using the static fluctuation approximation (SFA). The energies are calculated with a second-quantized many-body Hamiltonian and a harmonic oscillator wave function. The specific heat capacity, internal energy, pressure, entropy and the Bose-Einstein (BE) occupation number of the system are determined as functions of temperature and for various values of interaction strength and number of particles. It is found that the number of particles plays a more profound role in the determination of the thermodynamic properties of the system than the HS diameter characterizing the interaction, that the critical temperature drops with the increase of the repulsion between the bosons, and that the fluctuations in the energy are much smaller than the energy itself in the weakly-interacting regime.Comment: 34 pages, 24 Figures. To appear in the International Journal of Modern Physics

Cytotoxic Effects of Pistacia khinjuk Seed Extracts on Different Cell Lines and its Mitogenic Effects on Blood Lymphocyte In Vitro

Reports indicated that extract Pistacia khinjuk has anti-inflammatory, antipyretic, antibacterial, and antiviral, in treating of diarrhea and throat infections and has hepatoprotective effects against acetaminophen and carbon tetrachloride. This study was undertaken to investigate the possible cytotoxic effects of methanolic and aqueous seeds extract of P. khinjuk on different tumors (rhabdomyosarcoma [RD] and murine mammary adenocarcinoma [Ahmed-Mohammed-Nahi-2003 (AMN-3)]) and normal cell lines (murine fibroblast) and its mitogenic effects on blood lymphocytes. The cytotoxic effects of P. khinjuk seed extracts were evaluated on two tumor cell lines, RD and murine mammary adenocarcinoma (AMN-3) and one normal cell line, murine fibroblast (L20B). Moreover, the mitogenic effects of the plant extract were studied, on human blood lymphocytes. Both methanolic and aqueous seed extracts of P. khinjuk significantly induced tumor cell lines and the normal cell line proliferation, especially in highest concentrations. The results show that the extracts induced significant increases in human blood lymphocyte proliferation at 72 h. This activity of plant extracts recommends it as a good mitogenic agent in researches; in conclusion, seed extracts of P. khinjuk induced proliferation of all tested cell lines. High concentrations of both aqueous and methanolic seed extracts of P. khinjuk showed mitogenic effects

The Bacillus Calmette-Guérin (BCG) Vaccine: Is it a better choice for the treatment of viral warts?

Objectives: This study aimed to compare the effectiveness of the bacillus Calmette-Guérin (BCG) vaccine with topical salicylic acid (SA) in the treatment of viral warts. Methods: This non-randomised controlled trial was conducted at the Al-Sader Teaching Hospital, Basrah, Iraq, from January 2016 to April 2017. A total of 201 patients with viral warts were injected with an intradermal purified protein derivative. Subsequently, those with negative tuberculin test results received an intradermal BCG vaccination, while those with positive results underwent conventional treatment with topical SA. Patients were assessed for any signs of improvement at one, two and three months. Results: Overall, 190 patients completed the trial; of these, 133 (70%) received the BCG vaccine and 57 (30%) were treated with topical SA. Complete response to treatment was observed in 9.8% and 5.3% of patients in the BCG and SA groups, respectively (P <0.001). Cure rates were significantly higher for patients with genital (22.2% versus 7.7%; P = 0.002) and common warts (8.5% versus 0%; P = 0.001) treated with the BCG vaccine; however, the reverse was true for flat warts (12.9% versus 25%; P = 0.041). A binary logistic regression analysis indicated that BCG therapy was the only significant independent predictor of positive treatment response (odds ratio: 7.56, 95% confidence interval: 3.72–15.36; P <0.001). Conclusion: The BCG vaccine was more effective than topical SA for treating viral warts, with the best response noted in the treatment of genital warts, followed by flat warts. However, plantar warts demonstrated least response to this treatment.Keywords: Human Papilloma Viruses; Warts; Immunotherapy; BCG Vaccine; Salicylic Acid; Clinical Trial; Treatment Effectiveness

Does modularity of metal-on-metal hip implants increase cobalt: chromium ratio?

Background: Blood metal ion levels are used in the surveillance of metal-on-metal (MoM) hip implants. Modular implants contain an extra source of metal debris that may affect the ratio of metal ions in the blood. Methods: This was a retrospective study of 503 patients with hip replacements made by a single manufacturer (Smith & Nephew, Warwick, UK) with the same bearing surface. There were 54 total hip arthroplasties, 35 Birmingham Mid-Head Resections and 414 hip resurfacings. Whole blood metal ion levels and their ratios were analysed to investigate the effect of a modular junction. Results: The cobalt:chromium ratios were greater in the total hip arthroplasty group (mean 2.3:1) when compared to the resurfacings group (mean 1.3:1, p = <0.05) and Birmingham Mid-Head Resection group (mean 1.1:1, p = 0.11). Conclusions: This study demonstrated a trend for a higher cobalt:chromium ratio in patients with MoM total hip replacement that may be due to metal debris from the modular stem-head junction. Further work is required to correlate clinical data with retrieval analysis to confirm the effect of taper material loss on the cobalt:chromium ratio

Clinical and hematological study of experimentally induced secondary copper deficiency in sheep

The study was conducted on ten male Awassi sheep to evaluate the clinical and hematological changes in addition to measure serum copper level of sheep suffering from secondary copper deficiency during 4 months period. Animals were divided randomly into two equal groups; One group was drenched with a mixture of ammonium molybdate 100 mg with 1g of sodium sulfate in 100 ml of water daily for induction of secondary copper deficiency. The second group left without treatment as a control group. The serum copper level, and complete blood picture (Red blood cells, hemoglobin, packed cell volume, total white blood cells, granulocytes %, lymphocyte %, and monocytes %), were estimated on day zero and repeated every two weeks. Results revealed the appearance of clinical signs of secondary copper deficiency in deficient (treated) group; including emaciation of all 5 animals, loss of wool and easily to detached, bleaching around the eye in one animal, change in wool color, and increased in respiratory and pulse rate compared with control group. The clinical examination of both groups revealed no significant differences in temperature, while there was a significant (P ≤ 0.05) difference in pulse rate and respiratory rate between treated (37.6 ± 3.07) and control (27.4 ± 1.53) group. Copper level decreased gradually to reach (0.64 ± 0.06 ppm) which regard subnormal level with a statistically significant decrease (after 2 months of treatment) in treated compared with control group. Blood parameters included (RBC, Hb, PCV, MCV, MCH, and MCHC) were recorded nonsignificant differences along the experiment period in treated compared with control group. Total WBC in the treated group was recorded variation in the values with the presence of a significant gradual decrease in the treated compared with the control group with non-significant differences in granulocyte %, monocyte %, and lymphocyte %