Simultaneous reduction and sulfonation of graphene oxide for efficient hole selectivity in polymer solar cells

Asghar Ali,Zuhair S. Khan,Mahmood Jamil,Yaqoob Khan,Nisar Ahmad,S. Ahmed 한국물리학회 2018 Current Applied Physics Vol.18 No.5

We developed sulfonated, reduced graphene oxide (S-RGO) through fuming/concentrated sulfuric acid treatment of graphene oxide (GO) in ambient conditions. It was demonstrated that the optical band gap and electrical conductivity of S-RGO are easily tunable, and depend on the level of reduction and sulfonation of GO. Whereas, reduction and sulfonation were found dependent on SO3 content, acid strength, and gas tightness of the reaction mixture. It's actually the water content of oleum that determines the nature of the final product. The easily adjustable band gap and electrical conductivity suggest that S-RGO can be employed as a potential hole extraction layer (HEL) material for several donor-acceptor systems. For P3HT:PC61BM based inverted polymer solar cells, it was observed that the shape of the JeV curve is tailorable with the choice of HEL. Compared to a 2.75% power conversion efficiency (PCE) attained with PEDOT:PSS, a PCE of 2.80% was achieved with tuned S-RGO. Our results imply that an S-RGO of sufficiently high band gap and conductivity can replace some of the state of the art HEL materials for a host of device applications.

Economic Impact Evaluation of Tourism Development in Accordance with Sustainable Tourism, Case Study

S,Ali Badri,Mehdi,Ramezanzadeh lasboyee 세계문화관광학회 2009 Conference Proceedings Vol.10 No.0

The identification and planning of tourism's actual and perceived economic impacts in rural areas as destination community in accordance with the sustainable tourism principles, has recently received significant attention. Thus, this study compares and analyzes the economic aspects of rural areas in accordance with the sustainable tourism principles before and after tourism development. The case study has been carried out on the rural areas of Dohezar district, Tonekabon Township, Iran. This area has eleven rural settlements and 216 households. Possessing beautiful natural landscapes, this area has been appealing to domestic tourists. The type of tourism in this area is nature-based tourism, reflected in the form of second homes. The methodology used in this study is descriptive-analytic, in which statistical test such as non-parametrical tests such as Wilcockson has been implemented with regard to the data type and the comparison before and after. The findings of this study indicate that the economic indicators of the villages under study have shown significant difference before and after the tourism development in accordance with the principles of sustainability and sustainable tourism; so much so that following the tourism development, positive economic impacts in these rural areas like the growth of employment in relation to the tourism sector and an increase of income as a result of tourism development were observed. But, in view of the fact that tourism development has occurred in the form of mass tourism, spontaneously and without any premeditated planning, it has brought about negative economic impacts such as increase in the price of goods and services, Economic seasonality, and excessive reliance of the rural areas upon the tourism sector, and unequal income distribution have been; something in conflict with the principles of sustainability and those of sustainable tourism.

Life-cycle Prediction of Steel Bridges using Reliability-based Fatigue Deterioration Profile: Case Study of Neka Bridge

Ali Sahrapeyma,Abdollah Hosseini,Mohammad S. Marefat 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.2

Fatigue deterioration profiles of critical elements in a railway truss bridge are determined using a probabilistic approach. A performance function including fatigue strength, R, and fatigue action, D, is used, where R is a material property with lognormal distribution. The random variable D depends on AASHTO category, stress spectrum and traffic features. By applying Monte-Carlo simulations on the performance function of each year, reliability index profile is calculated. The reliability profile decreases with life, and whenever reaches to a critical value, an MR&R action should be implemented. A numerical approach is presented to specify the effects of MR&R actions on the deterioration profile. These actions include re-welding, attaching CFRP and combination of them. The structural model is calibrated by results of a loading test. In addition, the uncertainties arisen from future traffic volume and the relevant S-N curve are considered by a statistical analysis. For a target reliability of 2.0, the retrofit time for deck and truss are estimated. Finally, the outputs of the research are used to recommend a plan for maintenance of Neka Bridge.

Synthesis of New Pyrazole, Triazole, and Thiazolidine-Pyrimido [4, 5-b] quinoline Derivatives with Potential Antitumor Activity

Ameen Ali Abu-Hashem,Ahmed S. Aly 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.3

2-Hydrazinyltetrahydropyrimido [4, 5-b] quinolin-4(3H)-one (3) was prepared by desulfurization reaction of S- and N-dimethyl derivatives 2 with hydrazine hydrate. Reactions of (3) with malonitrile, carbondisulfide, potassium thiocyanate, phthalic anhydride and aromatic aldehydes afforded 3, 5-di aminopyrazolopyrimido [4, 5-b] quinoline (4), triazolotetrahydropyrimido [4, 5-b] quinoline (5), aminotriazolopyrimido [4, 5-b] quinoline (6), aminophthalimidopyrimido [4, 5-b] quinoline (7) and N-arylidene hydrazinepyrimido [4, 5-b] quinoline 8a-d, respectively. Furthermore, 8a-d reacted with mercaptoacetic acid gave the thiazolidinonepyrimido [4, 5-b] quinoline 9a-d, which afforded the thiazolotriazolopyrimido [4, 5-b] quinolinone 10a-d upon treatment with ethanolic potassium hydroxide. The newly synthesized compounds were characterized by elemental analyses, IR, 1H-NMR, 13C-NMR and mass spectrometer. The investigated compounds were screened for their cytotoxicity. Compounds 4, 6 and 5 exhibited potent antitumor activity.

Phase Segregation in the Mixed Alkyl Thiol Self-assembled Monolayers on a Gold Surface at a High Incubation Temperature in a Sealed Container

마문,Ali A. S. M. Zahid,이인섭,강홍석,한재량 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.11

Self-assembled monolayers (SAMs) of mixed 1-octanethiol (OT) and 1-decanethiol (DT) that were formed on gold substrates at a high incubation temperature in a sealed container were characterized using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In mixed-composition monolayer films, self-assembly of the mixture could induce phase separation into discrete molecular domains at higher incubation temperatures. Mixtures of the alkanethiol molecules affected the domain size, defect density, packing density, and binding features of the resultant SAMs prepared on gold substrates. Single-molecule-resolved STM images of mixed SAMs revealed both c(4 × 2) − ns (non-shifted) for DT and c(4 × 2) − s (shifted) for OT domains. For the mixed SAMs, the peak S2 (XPS) increased in intensity relative to the peak S1, reflecting significant modifications in the binding characteristics of the thiols and surface roughness upon mixing.

Preparation and Characterization of Thin Films Bismuth(III) Oxide/Zinc Oxide Nanostructures Prepared by Thermal Evaporation Technique as Gas Sensor Applications

Hassanein S. Suhail,Ali R. Abdulridha 한국전기전자재료학회 2024 Transactions on Electrical and Electronic Material Vol.25 No.1

In This work, they made Bismuth oxide (Bi2O3-based) and zinc oxide (ZnO)–doped thin films using thermal evaporation. XRD confirms the phase geometries of monoclinic and (Bi2O3/ZnO) thin films. When ZnO is added, the average crystal size decreases from 17.35 to 8.67 nm. Structures have been examined using Fourier transform infrared (FT-IR) and scanning electron microscopy. The Fourier transform infrared (FT-IR) investigation found no chemical reactions in the (Bi2O3/ZnO) thin films. A scanning electron microscopy (SEM) examination of the (Bi2O3/ZnO) thin films showed uniform results. Increased ZnO doping reduces the diameter by 67.6%, from 34.20 to 11.06 nm. The optical properties of the (Bi2O3/ZnO) thin film material are examined in this work. It has been shown that (Bi2O3/ZnO) concentration increases absorbance and absorption coefficients. The transmittance and energy band gaps decreased as ZnO concentrations with significant UV light absorption increased. The direct current (D.C) electrical conductivity of (Bi2O3/ZnO) thin films is positively correlated with (ZnO) nanoparticle concentration and temperature, according to experiments. At the same time, the activation energy falls with (ZnO) nanoparticle concentration, given a fixed quantity. The gas sensor showed 96.4% sensitivity to H2S gas at 200°C. The experiment employed 50 ppm H 2 S. Finally, the (Bi2O3/ZnO) thin film examination reveals their structural characteristics and conductivity. These results may be helpful in UV sensors and gas sensors. The utilisation of (Bi2O3/ZnO) thin film gas sensor has demonstrated significant potential as a viable option for gas sensing systems, primarily attributed to the enhanced surface area achieved by the application of metal oxide catalysts. The present study also discusses the mechanisms implicated in the augmentation of gas response and the broadened range of applications.

Maternal and Neonatal Outcomes of Critically Ill Pregnant and Puerperal Patients Diagnosed with COVID-19 Disease: Retrospective Comparative Study

Eman Ali,Balaban Onur,Kocayiğit Havva,Süner Kezban Özmen,Cırdı Yaşar,Erdem Ali Fuat 대한의학회 2021 Journal of Korean medical science Vol.36 No.44

Background: We assessed maternal and neonatal outcomes of critically ill pregnant and puerperal patients in the clinical course of coronavirus disease 2019 (COVID-19). Methods: Records of pregnant and puerperal women with polymerase chain reaction positive COVID-19 virus who were admitted to our intensive care unit (ICU) from March 2020 to August 2021 were investigated. Demographic, clinical and laboratory data, pharmacotherapy, and neonatal outcomes were analyzed. These outcomes were compared between patients that were discharged from ICU and patients who died in ICU. Results: Nineteen women were included in this study. Additional oxygen was required in all cases (100%). Eight patients (42%) were intubated and mechanically ventilated. All patients that were mechanically ventilated have died. Increased levels of C-reactive protein (CRP) was seen in all patients (100%). D-dimer values increased in 15 patients (78.9%); interleukin-6 (IL-6) increased in 16 cases (84.2%). Sixteen patients used antiviral drugs. Eleven patients were discharged from the ICU and eight patients have died due to complications of COVID-19 showing an ICU mortality rate of 42.1%. Mean number of hospitalized days in ICU was significantly lower in patients that were discharged (P = 0.037). Seventeen patients underwent cesarean-section (C/S) (89.4%). Mean birth week was significantly lower in patients who died in ICU (P = 0.024). Eleven preterm (57.8%) and eight term deliveries (42.1%) occurred. Conclusion: High mortality rate was detected among critically ill pregnant/parturient patients followed in the ICU. Main predictors of mortality were the need of invasive mechanical ventilation and higher number of days hospitalized in ICU. Rate of C/S operations and preterm delivery were high. Pleasingly, the rate of neonatal death was low and no neonatal COVID-19 occurred.

Mechanical and Thermal Characteristics of Optimized Electrospun Nylon 6,6 Nanofibers by Using Taguchi Method

Saleh S. Abdelhady,Said H. Zoalfakar,M. A. Agwa,Ashraf A. Ali 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11

This study is an attempt to optimize the electrospinning process to produce minimum Nylon 6,6 nanofibers by using Taguchi statistical technique. Nylon 6,6 solutions were prepared in a mixture of formic acid (FA) and Dichloromethane (DCM). Design of experiment by using Taguchi statistical technique was applied to determine the most important processing parameters influence on average fiber diameter of Nylon 6,6 nanofiber produced by electrospinning process. The effects of solvent/nylon and FA/DCM ratio on average fiber diameter were investigated. Optimal electrospinning conditions were determined by using the signal-to-noise (S/N) ratio that was calculated from the electrospun Nylon 6,6 nanofibers diameters according to "the-smaller-the-better" approach. The optimum Nylon 6,6 concentration (NY%) and FA/DCM ratio were determined. The morphology of electrospun nanofibers is significantly altered by FA/DCM solvent ratio as well as Nylon 6,6 concentration. The smallest diameter and the narrowest diameter distribution of Nylon 6,6 nanofibers (166 ffi 33 nm) were obtained for 10 wt% Nylon 6,6 solution in 80 wt% FA and 20 wt% DCM. An increase of 118%, 280% and 26% in tensile strength, modulus of elasticity and elongation at break over as-cast was obtained, respectively. Glass transition temperature of Nylon 6,6 nanofibers were determined by using differential scanning calorimeter (DSC). Analysis of variance ANOVA shows that NY% is the most influential parameter.

Effects of Heating, Storage, and Ultraviolet Exposure on Antimicrobial Activity of Garlic Juice

Noori S. Al-Waili,Khelod Y. Saloom,M. Akmal,Thia N. Al-Waili,Ali N. Al-Waili,Hamza Al-Waili,Amjed Ali,Karem Al-Sahlani 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.1

This study was designed to investigate the effect of heating, storage, and ultraviolet exposure on antimicrobialactivity of garlic juice and its bacteriocidal activity against common human pathogens. Antimicrobial activity of fresh garlicjuice was tested against Escherichia coli, Staphylococcus aureus, Streptococcus hemolyticusB, S. hemolyticusA, Klebsiellasp., Shigella dysenteriae, and Candida albicansusing the disc method. The dilution method was performed by addition ofgarlic juice to broth media to obtain 1100% concentrations as vol/vol or wt/vol. Garlic juice was used after 24 hours of stor-age at 4°C, heating to 100°C for 5 minutes, 10 minutes, 30 minutes, and 60 minutes, heating to 80°C for 60 minutes, and 4hours of exposure to ultraviolet light. Re-culture of specimens taken from garlic-induced negative media was performed infresh broth free of garlic juice. Results showed that all the isolates were sensitive to fresh garlic juice; the most sensitive wasC. albicans, and the least sensitive was S. hemolyticusA. Heating to 100°C for 30 and 60 minutes completely abolished theantimicrobial activity, while heating for 5 and 10 minutes, storage for 24 hours, and 4 hours of ultraviolet exposure decreasedit. Garlic juice was bactericidal at concentrations of 5% and more. Thus garlic juice has marked antimicrobial activity thatmakes it a potential agent to be tested in clinical trials. The antimicrobial activity was compromised by storage and heating;therefore it is advisable to use fresh garlic and avoid boiling it for more than 5 minutes during cooking.

Prevalence and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus from Nasal Specimens: Overcoming MRSA with Silver Nanoparticles and Their Applications

Abo-Amer Aly E.,Gad El-Rab Sanaa M. F.,Halawani Eman M.,Niaz Ameen M.,Bamaga Mohammed S. 한국미생물·생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.12

Staphylococcus aureus is a cause of high mortality in humans and therefore it is necessary to prevent its transmission and reduce infections. Our goals in this research were to investigate the frequency of methicillin-resistant S. aureus (MRSA) in Taif, Saudi Arabia, and assess the relationship between the phenotypic antimicrobial sensitivity patterns and the genes responsible for resistance. In addition, we examined the antimicrobial efficiency and application of silver nanoparticles (AgNPs) against MRSA isolates. Seventy-two nasal swabs were taken from patients; MRSA was cultivated on Mannitol Salt Agar supplemented with methicillin, and 16S rRNA sequencing was conducted in addition to morphological and biochemical identification. Specific resistance genes such as ermAC, aacA-aphD, tetKM, vatABC and mecA were PCR-amplified and resistance plasmids were also investigated. The MRSA incidence was ~49 % among the 72 S. aureus isolates and all MRSA strains were resistant to oxacillin, penicillin, and cefoxitin. However, vancomycin, linezolid, teicoplanin, mupirocin, and rifampicin were effective against 100% of MRSA strains. About 61% of MRSA strains exhibited multidrug resistance and were resistant to 3-12 antimicrobial medications (MDR). Methicillin resistance gene mecA was presented in all MDR-MRSA strains. Most MDR-MRSA contained a plasmid of > 10 kb. To overcome bacterial resistance, AgNPs were applied and displayed high antimicrobial activity and synergistic effect with penicillin. Our findings may help establish programs to control bacterial spread in communities as AgNPs appeared to exert a synergistic effect with penicillin to control bacterial resistance.