Hydraulic characteristics analysis of an anaerobic rotatory biological contactor (AnRBC) using tracer experiments and response surface methodology (RSM)

Yadollah Mansouri,Ali Akbar Zinatizadeh,Parviz Mohammadi,Mohsen Irandoust,Aazam Akhbari,Reza Davoodi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.7

The hydraulic characteristic of an anaerobic rotating biological contactor (AnRBC) were studied by changing two important hydraulic factors effective in the treatment performance: the hydraulic retention time (τ) and rotational disk velocity (ω). The reactor hydraulic performance was analyzed by studying hydraulic residence time distributions (RTD) obtained from tracer (Rhodamine B) experiments. The experiments were conducted based on a central composite face-centered design (CCFD) and analyzed using response surface methodology (RSM). The region of exploration for the process was taken as the area enclosed by τ (60, 90 and 120 min) and ω (0.8 and 16 rpm) boundaries. Four dependent parameters, deviation from ideal retention time (Δτ), dead volume percentage and dispersion indexes (Morrill dispersion index (MDI) and dispersion number (d)), were computed as response. The maximum modeled Δτand dead volume percentage was 43.03 min and 37.51% at τ and ω 120 min and 0 rpm, respectively. While, the minimum predicted responses (2.57 min and 8.08%) were obtained at τ and ω 60min and 16 rpm, respectively. The interaction showed that disk rotational velocity and hydraulic retention time played an important role in MDI in the reactor. The AnRBC hydraulic regime was classified as moderate and high dispersion (d=0.09 to 0.253). As a result, in addition to the factors studied, the reactor geometry showed significant effect on the hydraulic regime.

Adsorption of p-Cresol on Al2O3 coated multi-walled carbon nanotubes: Response surface methodology and isotherm study

Jalil Jaafari,Mohammad Ghanbari Ghozikali,Ali Azari,Mohammadbagher Delkhosh,Allah Bakhsh Javid,Ali Akbar Mohammadi,Shilpi Agarwal,Vinod Kumar Gupta,Mika Sillanpää,Alexey G. Tkachev,Alexander E. Burako 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

The development and design of adsorbents with high adsorption performance is an effective method of removing p-Cresol from effluent for environmental protection. Therefore, an Al2O3 coated multiwalled carbon nanotubes (MWNTs) composite for adsorption of p-Cresol from aqueous solution was synthesized. The p-Cresol concentration was determined by estimating the absorbance of the sample solution on a DR5000 UV/vis spectrophotometer. Box–Behanken design (BBD) was involved in the optimization of p-Cresol adsorption upon Al2O3 coated MWNTs adsorbent against the process parameters time, pH and adsorbent dose. The effects of these factors were studied in the ranges 5–40 min, 4–10, and 0.2–2 g L−1, respectively. The lack of fit obtained for this model was 0.357 which confirmed that the model is highly significant and the experiments are accurate and reliable. The results showed that adsorption isotherms fit well with the pseudo-second-order kinetic model and Langmuir isotherm model and Qmax was calculated to be 54.05 mg/g. Our results demonstrate that Al2O3 coated MWNTs has the potential to be used as an effective adsorbent for the rapid uptake of p-Cresol from aqueous solutions.

Collision-free local planner for unknown subterranean navigation

Jung, Sunggoo,Lee, Hanseob,Shim, David Hyunchul,Agha-mohammadi, Ali-akbar Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.4

When operating in confined spaces or near obstacles, collision-free path planning is an essential requirement for autonomous exploration in unknown environments. This study presents an autonomous exploration technique using a carefully designed collision-free local planner. Using LiDAR range measurements, a local end-point selection method is designed, and the path is generated from the current position to the selected end-point. The generated path showed the consistent collision-free path in real-time by adopting the Euclidean signed distance field-based grid-search method. The results consistently demonstrated the safety and reliability of the proposed path-planning method. Real-world experiments are conducted in three different mines, demonstrating successful autonomous exploration flights in environment with various structural conditions. The results showed the high capability of the proposed flight autonomy framework for lightweight aerial robot systems. In addition, our drone performed an autonomous mission in the tunnel circuit competition (Phase 1) of the DARPA Subterranean Challenge.

Social determinants of adherence to COVID-19 preventive guidelines: a comprehensive review

Zahra Jorjoran Shushtari,Yahya Salimi,Sina Ahmadi,Nader Rajabi-Gilan,Marzieh Shirazikhah,Akbar Biglarian,Ali Almasi,Mohammad Ali Mohammadi Gharehghani 질병관리본부 2021 Osong Public Health and Research Persptectives Vol.12 No.6

Adherence to coronavirus disease 2019 (COVID-19) preventive guidelines (ACPG) is an important strategy to control the COVID-19 pandemic effectively. The present study aimed to identify and summarize the social determinants of ACPG among the general population. A comprehensive review was performed from December 2019 to February 2021 through searching electronic databases. Two independent reviewers assessed and selected relevant studies. Next, the characteristics and main findings of the included studies were summarized. Finally, the World Health Organization’s conceptual framework of social determinants of health was used to synthesize the identified social determinants of ACPG. Forty-one of 453 retrieved articles met the inclusion criteria. The study results showed different patterns of ACPG among various communities. Furthermore, 84 social determinants were identified and categorized into structural and intermediary determinants. ACPG is a set of complex behaviors associated with different individual sociodemographic and behavioral characteristics; living and working conditions; COVID-19 knowledge, attitudes, and risk perceptions; exposure to sources and information level; leisure activities; social support; trust; social norms; psychosocial well-being; socio-economic position; and the socio-economic and political context. Interventions to promote ACPG among the general population should consider the identified social determinants of ACPG.

Seroreactivity to Helicobacter pylori Antigens as a Risk Indicator of Gastric Cancer

Karami, Najmeh,Talebkhan, Yeganeh,Saberi, Samaneh,Esmaeili, Maryam,Oghalaie, Akbar,Abdirad, Afshin,Mostafavi, Ehsan,Hosseini, Mahmoud Eshagh,Mohagheghi, Mohammad Ali,Mohammadi, Marjan Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.3

Background: Multiple etiologic factors are suspected to cause gastric cancer, the most important of which is infection with virulent types of Helicobacter pylori. Materials and Methods: We have compared 102 gastric cancer patients with 122 non-ulcer, non-cancer dyspeptic patients. Gastric specimens were evaluated for H. pylori infection by tissue-based detection methods. Patient sera underwent antigen-specific ELISA and western blotting using a Helicoblot 2.1 kit and antibody responses to various H. pylori antigens were assessed. Results: The absolute majority (97-100%) of both groups were H. pylori seropositive. Multivariate regression analysis demonstrated serum antibodies to the low molecular weight 35kDa protein to be protective and reduce the risk of gastric cancer by 60% (OR:0.4; 95%CI:0.1-0.9). Conversely, seroreactivity to the 89kDa (VacA) protein was significantly higher in gastric cancer patients (OR:2.7; 95%CI:1.0-7.1). There was a highly significant association (p<0.001) between seroreactivity to the 116kDa (CagA) and 89kDa (VacA) proteins, and double positive subjects were found at nearly five fold (OR:4.9; 95%CI:1.0-24.4) enhanced risk of gastric cancer as compared to double negative subjects. Conclusions: Seroreactivity to H. pylori low (35kDa) and high (116kDa/89kDa) molecular weight antigens were respectively revealed as protective and risk indicators for gastric cancer.

Evaluation of a Polycaprolactone/Gelatin/Lucilia sericata Larva Extract Nanofibrous Mat for Burn-Wound Healing

Seyedeh‑Sara Hashemi,Zhila Hayatdavoodi,Mehdi Kian,Nahid Hassanzadeh Nemati,Davood Mehrabani,Ali‑Akbar Mohammadi,Alireza Rafati,Mojtaba Ghaedi,Behzad Ghafari,Adnan Alizadeh Naini 한국섬유공학회 2023 Fibers and polymers Vol.24 No.11

Electrospun nanofibrous mats have shown great potential for dressing skin wounds. In this study, a nanofibrous mat composed of polycaprolactone (PCL), Gelatin (GLT), and Lucilia sericata larva extract (LSLE) was fabricated by the electrospinning method. The morphology of the fabricated nanofibrous mat and its morphological properties (fibers distribution frequency, fiber diameter, pore area, number of pores, and intersection density) were evaluated by scanning electron microscopy (SEM) and ImageJ software. The PCL/GLT/LSLE nanofibrous mat had well-branched and porous structure with a mean diameter of 500.2 ± 20.46. The presence of functional groups of PCL and GLT polymers in the structure of the PCL/GLT/LSLE mat was confirmed by Fourier-transform infrared spectroscopy (FTIR). Contact angle measurement and swelling behavior assessment showed that the PCL/GLT/LSLE mat had better surface wettability (75.67 ± 2.71) and hydrophilicity (241.8 ± 27.01) properties in comparison with the PCL and PCL/GLT mats. Findings from the MTT assay indicated the biocompatibility of the PCL/GLT/LSLE mat for human dermal fibroblasts (HDFs). In addition, the anchorage and proliferation of HDFs on the PCL/GLT/LSLE mat was confirmed by SEM. Macroscopic and histopathological evaluations were performed at the end of the 3, 7, and 14 days after the conduction of experimental burn wound injury in rats. The results indicated that grafting the skin wounds with the PCL/GLT/LSLE nanofibrous mat accelerated the wound closure and improved histopathological score compared to the other animal groups dressed with the PCL and PCL/GLT mats. In conclusion, the PCL/GLT/LSLE nanofibrous mat has promising potential for dressing skin wounds.