On the Detectability of CMB Anisotropies Induced by de Sitter-G\"odel-de Sitter Phase Transition

A geometrical phase transition in the very early Universe, from de Sitter to G\"odel and back to de Sitter (dGd) spacetimes, can explain the universal phenomenon of rotation of many large scale structures. This phase transition is shown to induce fluctuations on the matter and radiation fields with possibly observable traces. In this work we simulate the dGd-induced inhomogeneities and use their power spectrum, parametrized by the parameter pair ($p_1, p_2$), as possible seeds of CMB anisotropies along with the standard inflationary perturbations. With the Planck 2018 observations, we find $p_1=0.008^{+0.003}_{-0.008}$ and $p_2= 0.002^{+0.001}_{-0.002}$ consistent with pure inflationary power spectrum and no hint for the dGd transition. Future large scale surveys can further tighten the constraints and probe the physics of the early Universe

Knowledge about AIDS among medical students in Iran

Young people are among the high risk group who are susceptible to sexually transmitted diseases. Several educational programs are scheduled to raise awareness about risky behaviours and to decrease the rate of the HIV pandemic. This cross sectional study showed that in young medical students, the level of awareness about HIV/AIDS increased during the years of academic education (not significant) and that males have a higher level of awareness than females. Higher awareness is desirable in this group due to their key role in the community

Complications leading to hospitalization due to consumption of anti-TB drugs in patients with tuberculosis in Gorgan, Iran (2007-12)

Background and Objective: Anti tuberculosis drugs therapy is the most effective method for controling the tuberculosis (TB). Early detection and appropriate treatment can prevent the TB-drug resistance. This study was carried out to determine the complications leading to hospitalization due to consumption of anti-TB drugs in patients with tuberculosis. Methods: In this descriptive-analytic study, 1550 records of patients with TB in urban and rural health centers of Gorgan, north of Iran were assessed during 2007-12. Checklist consists of demographic and clinical data for each patient was recorded in a questionare. Results: 44 cases experienced the complications of anti-TB drugs. 27 (61.4%) of cases with complications were women. 77.3% and 22.7% of patients affected with pulmonary and extra pulmonary tuberculosis,respectively. 38.6% of patients were diabetic. The hepatic complication was seen in 37 cases (84.1%). Skin and other complications were seen in 5 and 2 cases, respectively. There was not any relationship between drug complications and other disases. Conclusion: Hepatic damage is the most common complication leading to hospitalization in tuberculosis patients using anti-TB drugs. Keywords: Tuberculosis, Anti-TB drug, Live

Removal of Cr (VI) from simulated electroplating wastewater by magnetite nanoparticles

زمینه و هدف: کروم به عنوان یکی از مهمترین آلاینده های محیط زیست محسوب می گردد و در غلظت های بالا در پســـاب صنایع آبکاری وجود دارد. نانو ذرات آهن مغناطیسی، با استفاده از مکانیسم های جذب سطحی، تعویض یونی و نیروهای الکترواستاتیک می تواند در کنترل و حذف فلزات سنگین از فاضلاب های صنعتی مورد استفاده قرار گیرد. هدف از انجام این تحقیق بررسی کارآیی نانو ذرات مغناطیسی در حذف کروم شش ظرفیتی (VI) از پساب های شبیه سازی شده صنایع آبکاری و پارامترهای موثر بر آن می باشد. روش بررسی: در این مطالعه تجربی نانو ذرات مگنتیت با استفاده از روش سل- ژل و با افزودن کلرور آهن دو و سه ظرفیتی در محیط مایی و تحت شرایط قلیایی تهیه گردید. سپس تاثیر عوامل موثر بر این فرآیند شامل، غلظت نانو ذره، غلظت اولیه کروم، pH محلول، سرعت اختلاط و زمان تماس، بررسی گردید. برای تعیین حجم نمونه از روش تاگوچی و تحلیل داده ها بر اساس مدل رگرسیون خطی ساده انجام شد. نمونه برداری بر مبنای پروتکل نمونه برداری انجام شد. یافته ها: یافته های این تحقیق نشان داد که در شرایط pH معادل 2، غلظت اولیه کروم ۱۰ میلی گرم بر لیتر، نانو ذرات مگنتیت سنتز شده با دوز 1 گرم بر لیتر، زمان تماس 5 دقیقه و سرعت همزن 250 دور در دقیقه، حدود 82 از کرم (VI) حذف شده بود. راندمان حذف با افزایش سرعت اختلاط افزایش معنی داری داشت (001/0

Investigation of heavy metals in edible mushrooms consumed in Shahrekord

زمینه و هدف: آلودگی به فلزات سنگین یکی از نگرانی های مهم بهداشت مواد غذایی است. وجود عناصر سمی در بستر قارچ ها ممکن است منجر به جذب آن ها شود که در این صورت مصرف قارچ با اشکال مواجه خواهد شد. این تحقیق با هدف تعیین غلظت عناصر سنگین منگنز، کروم، آهن، سرب، روی و مس در قارچ خوراکی موجود در شهرکرد صورت گرفته است. روش بررسی: این مطالعه به روش مقطعی- توصیفی انجام گرفت. 6 نمونه از قارچ های خوراکی پرورشی موجود در بازار شهرکرد و 2 نمونه از قارچ خوراکی وحشی انتخاب گردید. نمونه برداری به روش سرشماری با 3 بار تکرار به فاصله ی زمانی یک ماهه در فصل بهار انجام شد. از هر نوع قارچ 3 نمونه و در مجموع تعداد 24 نمونه گرفته شد. نمونه ها با استفاده از روش هضم اسیدی هضم شدند، سپس توسط دستگاه اسپکترو متری جذب اتمی غلظت عناصر تعیین گردید. یافته ها: میانگین مقادیر سنجش شده روی (94/14±29/61)، (11/29±48/58)، آهن (69/8±29/26)، (93/11±30/28)، سرب (56/0±05/2)، (35/0±07/2)، کروم (41/0±46/1)، (91/0±1/1)، مس (68/5±99/22)، (67/6±83/25) و منگنز (72/0±8/3)، (99/0±25/6) میلی گرم در کیلوگرم به ترتیب در قارچ های پرورشی و وحشی به دست آمد. یافته های این تحقیق نشان می دهد که میانگین غلظت روی در هر 2 نوع قارچ (وحشی- پرورشی) در حد مجاز استاندارد (CODEX/FAO/WHO) کروم، سرب، آهن بیش تر از حد مجاز استاندارد و منگنز، مس کم تر از حد مجاز استاندارد به دست آمد. نتیجه گیری: با توجه به اینکه برخی نمونه ها حاوی فلز سنگین کروم، سرب، آهن با مقادیر بالاتر از حد مجاز می باشند و با توجه به مصرف روز افزون قارچ های خوراکی پرورشی در ایران دقت بیش تری در مورد شرایط و محیط پرورشی قارچ ها لازم می باشد

SYNTHESIS OF MAGNETITE NANOPARTICLES AND EVALUATION OF ITS EFFICIENCY FOR ARSENIC REMOVAL FROM SIMULATED INDUSTRIAL WASTEWATER

In this study the efficiency of magnetic nanoparticles for removal of trivalent arsenic from synthetic industrial wastewater was evaluated. The nanoparticles was prepared by sol-gel method and characterized by X-ray methods including XRD, XRF, and SEM, and vibrating sample magnetometer (VSM). The results showed that synthesized nanoparticles were in the size range of 40-300 nm, purity of about 90%, and magnetization of nanoparticles was 36.5emu/g. In initial conditions including: pH=7, As(III) concentration of 10 mg/L, nanomagnetite concentration of 1g/L, shaking speed of 250 rpm and 20 minute retention time, 82% of As (III) was removed. Competition from common coexisting ions such as Na+, Ni2+, Cu2+, SO42-, and Cl- was ignorable but for NO3- was significant. The adsorption data of magnetite nanoparticles fit well with Freundlich isotherm equations. The adsorption capacity of the Fe3O4 for As (Ill) at pH=7 was obtained as 23.8 mg/g. It was concluded that magnetite nanoparticles have considerable potential in removal of As(III) from synthetic industrial wastewaters

Silica-Supported Yttrium Nitrate Hexahydrate as a Heterogeneous Catalyst for the Synthesis of 2-Amino-4H-Chromenes in Water

Silica-supported yttrium nitrate hexahydrate (Y(NO3)3.6H2O/SiO2) has been found to be an efficient and reusable catalyst for the synthesis of 2-amino-4H-chromenes via a one-pot aqueous three-component reaction between arylaldehydes, malononitrile and â-naphthol in high yields. This method has many appealing attributes such as excellent yields, short reactions time, reusability of the catalyst and simple work-up procedure.KEYWORDS: Silica-supported yttrium nitrate hexahydrate, 2-amino-4H-chromene, malononitrile, arylaldehyde, β-naphthol

Increasing of leachate quality using an integrated aerobic membrane bioreactor

The aim of this study was the increasing of leachate quality using integrated membrane bioreactor (MBR). The reactor was fed with treated leachate with overall 70-1360 mg/l chemical oxygen demand (COD). The analysis of COD, biochemical oxygen demand (BOD5), total suspended solids (TSS), and total dissolved solids (TDS) were performed in feed and filtrate, whenever the system reached steady state twice a week for 6 months. In all loading rate, BOD5 concentration was less than the standard limit. The removal efficiency of COD in all experiments was up to 80%. Up to 99% of solids, which may mainly include colloidal solids, were removed with micropore membrane. There was no significant difference between TDS concentration in feed and filtrate. It was concluded that MBR is a versatile technology with high throughput and can treat compost leachate below standard limit if used after appropriate processes. KEYWORDS: Leachate, Bioreactor, Waste Disposal, Membran

New polymerization-mixture formulation for jetting: An approach to production of polyamide 6 parts

Poor mechanical properties of manufactured parts is one of the main problems in most of the RP and RM processes. This work deals with a study on formulation of new polymerization mixtures with the aim of being used in jetting process. Two different catalyst components were compared in order to shorten the solidification time and improve the final properties of the manufactured part. The feasibility of jetting polymerization mixtures at jetting head temperature was also investigated. Different characterization and visualization methods (i.e. such as DSC, viscometry, TGA, and hot stage optical microscopy) were used to monitor the polymerization progress and manufactured part properties.Mechanical Engineerin

REMOVAL OF Cr(VI) FROM SIMULATED ELECTROPLATING WASTEWATER BY MAGNETITE NANOPARTICLES

In this study, the efficiency of magnetic nanoparticles for removal of hexavalent chromium from simulated electroplating wastewater was evaluated. The nanoparticles were prepared using the sol-gel method and were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), a scanning electron microscopy energy dispersive X-ray analyzer (SEM-Edx), a particle sizer and a vibrating sample magnetometer (VSM). The results showed that synthesized nanoparticles were in the size range of 40-300 rim, had purity of about 90 percent, and had magnetization of 36.5 electromagnetic unit per gram (emu/g). In conditions including pH 2, Cr (VI) concentration of 10 mg/L, nanomagnetite concentration of 1 g/L, a shaking speed of 250 rpm and a 20 minute retention time, 82% of Cr(VI) was removed. Competition from common coexisting ions such as Na(+), Ni(2+), Cu(2+), NO(3)(-), SO(4)(2-), and Cl was negligible. The adsorption data was well fitted by the Freundlich isotherm. It was concluded that magnetite nanoparticles have considerable potential for removal of Cr(VI) from electroplating wastewaters