N-doped reduced graphene oxide aerogel for the selective adsorption of oil pollutants from water: Isotherm and kinetic study

Zahra Rahmani,Alimorad Rashidi,Abbass kazemi,Mohhammad Taghi Samadi,Ali Reza Rahmani 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.61 No.-

N-doped graphene aerogel with a 3D inter-connected network was synthesized using graphene oxide and pyrrole in an aqueous medium with ammonia. Hydrothermal and thermal annealing methods were employed to do it so. The structure and surface properties of the synthesized aerogel were characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), XPS, and nitrogen adsorption/desorption measurements. The prepared n-doped aerogel exhibited elevated specific surface area (340 m2/g), hydrophobic nature, and excellent adsorption capacity (210 g/g for crude oil removal). Adsorbent recyclability was also investigated; it is worth noting that after ten subsequent cycles, only just a negligible decrement in adsorption capacity was observed. Furthermore, the effect of salts and temperature on adsorption capacity was studied. Isotherm and kinetic studies were last examined. The conformity of various adsorption models, including Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich (D–R) to the equilibrium data was evaluated among which Langmuir isotherm model gave the best fitting result. The sorption kinetics data were well described by the pseudo-second-order kinetic model. As a consequence, oil spills adsorption using n-doped graphene aerogel is a relatively cost-effective method which can be scaled up, and it could be a promising material for removal of organic contaminants from water.

Investigation of photocatalytic degradation of clindamycin antibiotic by using nano-ZnO catalysts

Mahdi Farzadkia,Kourosh Rahmani,Mitra Gholami,Ali Esrafili,Ayat Rahmani,Hassan Rahmani 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.11

The photocatalytic degradation of clindamycin (CLM) was studied by a batch reactor using UV irradiationand ZnO catalyst. The effects of several parameters such as pH, catalyst loading, light intensity and irradiation timewere evaluated in the removal process. The results showed that the degradation of CLM was effective in alkaline con-ditions. The optimum catalyst loading in an aqueous solution containing 25 mM of CLM and UV lamp of 50W wasobserved at 3.0 g/L of catalyst loading. The process followed pseudo-first order kinetics, and the apparent rate constant(k) decreased with increasing the initial concentration of CLM. The photocatalytic process had higher removal efficiencyin synthetic than actual wastewater in optimum conditions.

Multimodal delivery of irinotecan from microparticles with two distinct compartments

Rahmani, Sahar,Park, Tae-Hong,Dishman, Acacia Frances,Lahann, Joerg Elsevier 2013 Journal of controlled release Vol.172 No.1

<P><B>Abstract</B></P> <P>In the last several decades, research in the field of drug delivery has been challenged with the fabrication of carrier systems engineered to deliver therapeutics to the target site with sustained and controlled release kinetics. Herein, we report the fabrication of microparticles composed of two distinct compartments: i) one compartment containing a pH responsive polymer, acetal-modified dextran, and PLGA (polylactide-<I>co</I>-glycolide), and ii) one compartment composed entirely of PLGA. We demonstrate the complete release of dextran from the microparticles during a 10-hour period in an acidic pH environment and the complete degradation of one compartment in less than 24h. This is in congruence with the stability of the same microparticles in neutral pH over the 24-hour period. Such microparticles can be used as pH responsive carrier systems for drug delivery applications where their cargo will only be released when the optimum pH window is reached. The feasibility of the microparticle system for such an application was confirmed by encapsulating a cancer therapeutic, irinotecan, in the compartment containing the acetal-modified dextran polymer and the pH dependent release over a 5-day period was studied. It was found that upon pH change to an acidic environment, over 50% of the drug was first released at a rapid rate for 10h, similar to that observed for the dextran release, before continuing at a more controlled rate for 4days. As such, these microparticles can play an important role in the fabrication of novel drug delivery systems due to the selective, controlled, and pH responsive release of their encapsulated therapeutics.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Rheological, physico-mechanical and durability properties of multi-recycled concrete

Rahmani, Abdessamed Azzaz,Chemrouk, Mohamed,Ammar-Boudjelal, Amina Techno-Press 2020 Advances in concrete construction Vol.9 No.1

The present work looks at the possibilities of recycling more than once demolished concrete as coarse aggregates, to produce new concrete. Different concrete mixes were made with substitutions of 50%, 75% and 100% of recycled concrete aggregates respectively as coarse aggregates. The physico-mechanical characterization tests carried out on the recycled concrete aggregates revealed that they are suitable for use in obtaining a structural concrete. The resulting concrete materials had rheological parameters, compressive strengths and tensile strengths very slightly lower than those of the original concrete even when 100% of two cycles recycled concrete aggregates were used. The durability of the recycled aggregates concrete was assessed through water permeability, water absorption and chemical attacks. The obtained concretes were thought fit for use as structural materials. A linear regression was developed between the strength of the material and the number of cycles of concrete recycling to anticipate the strength of the recycled aggregates concrete. From the results, it appear clear that recycling demolished concrete represents a valuable resource for aggregates supply to the concrete industry and a the same time plays a key role in meeting the challenge for a sustainable development.

Descriptive Study of Occupational Accidents and their Causes among Electricity Distribution Company Workers at an Eight-year Period in Iran

Rahmani, Abdolrasoul,Khadem, Monireh,Madreseh, Elham,Aghaei, Habib-Allah,Raei, Mehdi,Karchani, Mohsen Occupational Safety and Health Research Institute 2013 Safety and health at work Vol.4 No.3

Background: Occupational accidents are unplanned events that cause damage. The socio-economic impacts and human costs of accidents are tremendous around the world. Many fatalities happen every year in workplaces such as electricity distribution companies. Some electrical injuries are electrocution, electric shock, and burns. This study was conducted in an electricity distribution company (with rotational 12-hour shift work) in Iran during an 8-year period to survey descriptive factors of injuries. Methods: Variables collected included accident time, age of injured worker, employment type, work experience, injury cause, educational background, and other information about accidents. Results: Results indicated that most of the accidents occurred in summer, and 51.3% were during shift work. Worker negligence (malpractice) was the cause of 75% of deaths. Type of employment had a significant relationship with type of injuries (p < 0.05). Most injuries were electrical burns. Conclusion: High rate of accidents in summer may be due to the warm weather or insufficient professional skills in seasonal workers. Shift workers are at risk of sleep complaints leading to a high rate of work injuries. Acquiring knowledge about safety was related to job experiences. Temporary workers have no chance to work all year like permanent workers, therefore impressive experiences may be less in them. Because the lack of protective equipment and negligence are main causes of accidents, periodical inspections in workshops are necessary.

Effect of electroforming polarity on bipolar resistive switching characteristics of transparent AZO/CeO₂/ITO memory

Rahmani Mehr Khalid,Khan Sobia Ali,Muhammad Ismail,Sungjun Kim 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6

Durability of CFRP strengthened RC beams under wetting and drying cycles of magnesium sulfate attack

Rahmani, Hamid,Alipour, Soha,Mansoorkhani, Ali Alipour Techno-Press 2019 Advances in concrete construction Vol.8 No.1

Durability of strengthened reinforced concrete (RC) beams with CFRP sheets under wetting and drying cycles of magnesium sulfate attack is investigated in this research. Accordingly, 18 RC beams were designed and made where 10 of them were strengthened by CFRP sheets at their tension side. Magnesium sulfate attack and wetting and drying cycles with water and magnesium sulfate solution were considered as exposure conditions. Finally, flexural performance of the beams was measured before and after 5 months of exposure. Results indicated that the bending capacity of the strengthened RC beams was reduced about 10% after 5 months of immersion in the magnesium sulfate solution. Wetting and drying cycles of magnesium sulfate solution reduced the bending capacity of the strengthened RC beams about 7%. Also, flexural capacity reduction of the strengthened RC beams in water and under wetting and drying cycles of water was negligible.

Design, Synthesis, Fluorescence Properties and Antibacterial Activities of New 8-Chloro-3-Alkyl-3H-Pyrazolo[4,3-a]acridine-11-Carbonitriles

Rahmani, Zeynab,Pordel, Mehdi,Davoodnia, Abolghasem Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.2

The treatment of alkylated nitro derivatives of indazole with 2-(4-chlorophenyl)acetonitrile under basic conditions gave the new 8-chloro-3-alkyl-3H-pyrazolo[4,3-a]acridine-11-carbonitriles via the nucleophilic substitution of hydrogen which proceeds at room temperature with concomitant cyclisation in fairly good yields. The structures of all newly synthesized compounds were confirmed by IR, $^1H$ NMR, $^{13}C$ NMR and mass spectral data. Fluorescence experimental results of all newly synthesized compounds revealed remarkable photoluminescence properties and strong green fluorescence properties. Also, the new compounds exhibited potent antibacterial activity and their antibacterial activity (MIC) against Gram positive (Staphylococcuse aureus methicillin resistant S. aureus and Bacillus subtilis) and negative bacterial (Pseudomonas aeruginosa and Escherichia coli) species were determined.

Evaluating the effects of probiotics in pediatrics with recurrent abdominal pain

Rahmani, Parisa,Ghouran-Orimi, Azin,Motamed, Farzaneh,Moradzadeh, Alireza The Korean Pediatric Society 2020 Clinical and Experimental Pediatrics (CEP) Vol.63 No.12

Background: Recurrent abdominal pain (RAP) is one of the frequent complaints in general practice, particularly in pediatrics and is among the common cause of referral to gastroenterology clinics. Purpose: This study is designed to investigate the effects of probiotics for the treatment of RAP and desired therapeutic outcomes. Methods: One hundred twenty-five children with the diagnosis of RAP according to Rome III criteria for irritable bowel syndrome (IBS), functional abdominal pain (FAP), functional dyspepsia (FD), and abdominal migraine (AM), were enrolled in this double-blind randomized controlled trial. Results: Sixty-five subjects received probiotics, and others received placebo treatment for 4 weeks. Lactobacillus reuteri was therapeutically effective in 32 patients compared to 8 patients, responding to the placebo treatment. Compared to baseline, all pain-related variables showed a significant reduction for the IBS and FD at the end of the 4th week. However, it did not respond well in FAP and AM groups. Pain-related outcomes such as, frequency of the pain, severity, and duration of the pain were decreased following the probiotic treatment. No therapeutic response was seen in AM group after the administration of probiotics. L. reuteri significantly led to pain relief in the overall population, and also in FAP, FD, and IBS subgroups. Conclusion: L. reuteri probiotics are likely to lead to RAP relief and can be recommended for the treatment of functional gastrointestinal disorders.

Noninvasive markers for esophageal varices in children with cirrhosis

Rahmani, Parisa,Farahmand, Fatemeh,Heidari, Ghobad,Sayarifard, Azadeh The Korean Pediatric Society 2021 Clinical and Experimental Pediatrics (CEP) Vol.64 No.1

Background: The diagnosis of esophageal varices (EV) is based on the findings of esophagogastroduodenoscopy (EGD), biopsy, and serum markers. Thus, noninvasive cost-effective tests through which high-risk EV children can be diagnosed are needed. Purpose: This cross-sectional study aimed to identify the noninvasive markers for EV in children with liver cirrhosis. Methods: A total of 98 children with liver cirrhosis were evaluated in this study. The spleen size, platelet count, serum albumin, liver function test results, and risk scores were evaluated prior to endoscopy. The endoscopic investigations aimed to identify the presence of EV and red signs, and determine varices sizes. Results: Endoscopy revealed varices in 43 subjects (43.9%). The spleen size, platelet count, international normalized ratio, aspartate aminotransferase to platelet ratio index (APRI), platelet count to spleen size ratio, and risk score differed significantly between patients with and without EV on univariate analysis; however, the logistic regression analysis showed no differences, indicating that none of these parameters were independently associated with the presence of EV. Conclusion: Platelet count, risk score, platelet count to spleen size, and APRI can be useful tools for the identification of high-risk patients with EV and might reduce the need for invasive methods like EGD.