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Evaluation of phytochemical and antimicrobial properties of Commelina diffusa Burm. f.
Ahad Ali Khan,Torequl Islam,Samir Kumar Sadhu 경희대학교 융합한의과학연구소 2011 Oriental Pharmacy and Experimental Medicine Vol.11 No.4
The results revealed that different fractions of Commelina diffusa Burm. f. produced significant (p<0.001,p<0.01, p<0.05, p<0.02 and p<0.5) inhibitory activity against the test bacteria and fungi. Methanolic fraction produced the highest zone of inhibition against the test bacteria (11 to 19 mm) which was followed by diethyl etheric extract (3 to 9 mm) and petroleum etheric extract (1 to 2 mm). Again, the methanolic extract showed the highest activity (the lowest MICs; 15.62 to 62.5 μg/μl) against seven species among the 11. In case of diethyl etheric and petroleum etheric fractions MICs were found to be (15.62 to 125 μg/μl)and (31.25 to 500 μg/μl), respectively. The diethyl etheric fraction showed the highest zone of inhibition against the fungi (15 to 19 mm) which was followed by methanolic extract (12 to 19 mm) and petroleum etheric extract (1 to 9 mm). Against the fungi the diethyl etheric extract showed the highest activity (i.e. the lowest MICs; 15.62 to 31.25 μg/μl). In case of methanolic and petroleum etheric fractions minimum inhibitory concentrations were found to be (15.62 to 125 μg/μl)and (31.25 to 250 μg/μl), respectively.
Investigation of near dry EDM compared with wet and dry EDM processes
Ahad Gholipoor,Hamid Baseri,Mohammadreza Shabgard 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.5
Material removal rate (MRR), tool wear ratio (TWR) and surface roughness (SR) obtained by near-dry EDM process were comparedwith wet and dry EDM at three levels of discharge energy in drilling of SPK steel. Surface integrity machined by this process was studiedand compared with wet and dry EDM processes, by scanning electron microscopy (SEM). The results showed that at high level of dischargeenergy, wet EDM has the most MRR, TWR and SR, and dry EDM has the least MRR, TWR and SR, while at low dischargeenergy levels, near-dry EDM process has the most MRR and the least SR. SEM micrographs showed that the quality of surface obtainedby near-dry EDM process is better than others and the machined surfaces by near-dry EDM process have lower micro-cracks and craters,relatively.
Study of hydrodynamics and iodine removal by self-priming venturi scrubber
Ahad Jawaria,Rizwan Talha,Farooq Amjad,Waheed Khalid,Ahmad Masroor,Qureshi Kamran Rasheed,Siddique Waseem,Irfan Naseem 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.1
Filtered containment system is a passive safety system that controls the over-pressurization of containment in case of a design-based accidents by venting high pressure gaseous mixture, consisting of air, steam and radioactive particulate and gases like iodine, via a scrubbing system. An indigenous lab scale facility was developed for research on iodine removal by venturi scrubber by simulating the accidental scenario. A mixture of 0.2 % sodium thiosulphate and 0.5 % sodium hydroxide, was used in scrubbing column. A modified mathematical model was presented for iodine removal in venturi scrubber. Improvement in model was made by addition of important parameters like jet penetration length, bubble rise velocity and gas holdup which were not considered previously. Experiments were performed by varying hydrodynamic parameters like liquid level height and gas flow rates to see their effect on removal efficiency of iodine. Gas holdup was also measured for various liquid level heights and gas flowrates. Removal efficiency increased with increase in liquid level height and gas flowrate up to an optimum point beyond that efficiency was decreased. Experimental results of removal efficiency were compared with the predicted results, and they were found to be in good agreement. Maximum removal efficiency of 99.8% was obtained.
Ahad, Abdul,Haque, Ekramul,Naaz, Sabiha,Bey, Afshan,Rahman, Sajjad Abdur The Korean Dental Society of Anesthsiology 2020 Journal of Dental Anesthesia and Pain Medicine Vol.20 No.6
Background: The anterior-middle superior alveolar (AMSA) anesthetic technique has been reported to be a less traumatic alternative to several conventional nerve blocks and local infiltration for anesthesia of the maxillary teeth, their periodontium, and the palate. However, its anatomic basis remains controversial. The present study aimed to determine if the pattern of cortical and cancellous bone density in the maxillary premolar region can provide a rationale for the success of the AMSA anesthetic technique. Method: Cone-beam computed tomography scans of 66 maxillary quadrants from 34 patients (16 men and 18 women) were evaluated using a volumetric imaging software for cortical and cancellous bone densities in three interdental regions between the canine and first molar. Bone density was measured in Hounsfield units (HU) separately for the buccal cortical, palatal cortical, buccal cancellous, and palatal cancellous bones. Mean HU values were compared using the Mann-Whitney U test and one-way ANOVA with post-hoc analysis. Results: Cancellous bone density was significantly lower (P ≤ 0.001) in the palatal half than in the buccal half across all three interdental regions. However, there was no significant difference (P = 0.106) between the buccal and palatal cortical bone densities at the site of AMSA injection. No significant difference was observed between the two genders for any of the evaluated parameters. Conclusions: The palatal half of the cancellous bone had a significantly lower density than the buccal half, which could be a reason for the effective diffusion of the anesthetic solution following a palatal injection during the AMSA anesthetic technique.
Ahad, S.,Ragupathy, P.,Ryu, S.,Lee, H. W.,Kim, D. unknown 2017 Chemical Communications Vol. No.
<P>Herein, we demonstrate a synergistic approach involving polar-based oxide and polysulfide additives for effectively suppressing polysulfide dissolution during cycling. The MnO2 hollow spheres not only provide physical confinement for the polysulfide species but also enable strong chemical interactions between polysulfide species and oxides, while the added polysulfide furnishes a mass buffering effect and compensates for the capacity losses due to partial cathode dissolution during discharge. The capacity retentions of S/KB, S/KB/LiPS, S/KB/MnO2, and S/KB/MnO2/LiPS composite cathodes are 31%, 45%, 59%, and 91% respectively. The remarkable capacity retention of the S/KB/LiPS/MnO2 composite electrode is mainly attributed to the synergistic effect between MnO2 and polysulfide additives.</P>
Ahad, Syed Abdul,Kumar, P. Ramesh,Kim, Joo-Hyung,Kim, Dong Jun,Ragupathy, P.,Kim, Do Kyung Pergamon Press 2017 Electrochimica Acta Vol. No.
<P><B>Abstract</B></P> <P>The Lithium–Sulfur battery is a promising high performance battery candidate for large-scale application on account of its high theoretical specific capacity. However, it has come up short on delivering long cycle life mainly due to the formation of soluble polysulfides, which results in the loss of active material during redox processes. In this study, we prepared three different graphene oxide based carbon hosts − graphene oxide (GO), thermally reduced GO (t-rGO) and dopamine-assisted chemically reduced GO (c-rGO) − and investigated their physical and electrochemical properties as a sulfur cathode. We found significant absorbance of polysulfides on the c-rGO host, which provided stable discharge capacity of 601mAhg<SUP>−1</SUP> at 0.5C for up to 300 cycles. This stable cycling behavior is further identified by <I>in-situ</I> UV–vis spectroscopy and <I>ex-situ</I> X-ray photoelectron spectroscopy, confirming the minimization of polysulfide dissolution toward the electrolyte through the adsorption of polydopamine coating.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Ahad Bavili Tabrizi 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.11
Cloud point extraction was used to extract mefenamic acid (MF) from human urine, and spectrofluorimetry and spectrophotometry were used to analyze extracted MF. The variables affecting extraction and phase separation, i.e. HCl and Triton X-114 concentration, temperature and time of equilibration, were optimized. Under the experimental conditions used the limit of detection for extraction of 25 mL of sample was 0.006 and 0.045 mg L-1, with relative standard deviations of 2.52 and 1.45% (n = 5) for spectrofluorimetric or spectrophotometric methods, respectively. Good recoveries in the range of 95-107% were obtained for spiked samples. The proposed methods were applied to the determination of MF in human urine.
A Cloud Point Extraction-Spectrofluorimetric Method for Determination of Thiamine in Urine
Ahad Bavili Tabrizi 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.10
A simple and efficient cloud point extraction-spectrofluorimetric method for the determination of thiamine in human urine is proposed. The procedure is based on the oxidation of thiamine with ferricyanide to form thiochrome, its extraction to Triton X-114 micelles and spectrofluorimetric determination. The variables affecting oxidation of thiamine, extraction and phase separation were studied and optimized. Under the experimental conditions used, the calibration graphs were linear over the range 2.5-1000 ng mL-1. The limit of detection was 0.78 ng mL-1 of thiamine and the relative standard deviation for 5 replicate determinations of thiamine at 400 ng mL-1 concentration level was 2.42%. Average recoveries between 93-107% were obtained for spiked samples. The proposed method was applied to the determination of thiamine in human urine.
Experimental investigation of CO2 capture using sodium hydroxide particles in a fluidized bed
Ahad Ghaemi,Sareh Naeem,Shahrokh Shahhosseini 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.4
CO2 capture from air using sodium hydroxide solid sorbent in a laboratory scale fluidized bed reactor was investigated experimentally. The influence of three parameters of temperature, inlet CO2 volume percentage and inlet air flow rate on the CO2 removal rate was studied. Experimental results showed that the optimum rate was at 25 oC when the inlet CO2 volume percentage was 1%. The results also showed that the adsorption process was reactive, and the reaction mechanism depended on the reaction temperature. In addition, empirical observation revealed only one adsorption cycle happened at low temperatures (25-30 oC). As the temperature increased, the second adsorption cycle occurred and, finally, CO2 desorption cycle took place in the range of 90-115 oC.