A Simple Spectrofluorimetric Method for Determination of Mefenamic Acid in Pharmaceutical Preparation and Urine

Ahad Bavili Tabrizi 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.8

Current status of the anterior middle superior alveolar anesthetic injection for periodontal procedures in the maxilla

Ahad, Abdul,Haque, Ekramul,Tandon, Shruti The Korean Dental Society of Anesthsiology 2019 Journal of Dental Anesthesia and Pain Medicine Vol.19 No.1

Periodontal procedures require adequate anesthesia not only to ensure the patient's comfort but also to enhance the operator's performance and minimize chair time. In the maxilla, anesthesia is often achieved using highly traumatic nerve blocks, apart from multiple local infiltrations through the buccal vestibule. In recent years, anterior middle superior alveolar (AMSA) field block has been claimed to be a less traumatic alternative to several of these conventional injections, and it has many other advantages. This critical review of the existing literature aimed to discuss the rationale, mechanism, effectiveness, extent, and duration of AMSA injections for periodontal surgical and non-surgical procedures in the maxilla. It also focused on future prospects, particularly in relation to computer-controlled local anesthetic delivery systems, which aim to achieve the goal of pain-free anesthesia. A literature search of different databases was performed to retrieve relevant articles related to AMSA injections. After analyzing the existing data, it can be concluded that this anesthetic technique may be used as a predictable method of effective palatal anesthesia with adequate duration for different periodontal procedures. It has additional advantages of being less traumatic, requiring lesser amounts of local anesthetics and vasoconstrictors, as well as achieving good hemostasis. However, its effect on the buccal periodontium appears highly unpredictable.

Influence of faulting on porosity and permeability features of carbonate rocks, Kardeh fault, NE Iran

Ahad Nouri Mokhoori,Behnam Rahimi,Nasser Hafezi Moghaddas,Mohamad Hosein Mahmudy Gharaie 한국지질과학협의회 2021 Geosciences Journal Vol.25 No.4

In the southern part of the Kopeh Dagh basin, NE Iran, outcrop of the Kardeh fault damage zone in Mozduran carbonate formation provides an opportunity for investigation of the impact of faulting on permeability and porosity. For this purpose, three methods were focused on: 1) gas injection in oriented cores prepared parallel and perpendicular to fault strike and parallel to fault dip, 2) microscopic analysis and 3) determining variation of the degree of fractures connectivity in the fault damage zone. Results of tests show air-porosity and air-permeability increase from fault core toward host rock. Using microscopic studies, we attribute these variations to bioclasts destruction and filling, precipitation of calcite cement in fractures and pores, development of compaction structures such as stylolites and particle abrasion. Analyzing variation of the fractures connectivity in the fault damage zone in macro-scale shows degree of connectivity increases from host rock toward fault core (Y and X nodes). Clear dependence between this parameter and fluid flow is reflected by connected linear springs developed in the damage zone in close proximity to the fault core. Results of this study show that permeability in a fault zone is a scale dependent feature.

Development and Microstructural Characterization of a New Wrought High Entropy Superalloy

Ahad Shafiee,Mahmoud Nili‑Ahmadabadi,Hyoung Seop Kim,Mohammad Jahazi 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.5

In this study, a newly developed γ′ precipitation hardened high entropy superalloy (designated as HES-A1 hereafter) wasproduced and its microstructural features were characterized. The new alloy composition is based on the major elementsof conventional IN718 alloy, however other elements were added or removed to minimize possible presence of δ (or γʺ)phase and increase the volume fraction of very fine γ′ precipitates instead. Broadening the hot working window, lowerdensity, and avoiding the use of expensive elements were other considerations taken into account in the design of the newalloy. CALPHAD (CALculation of PHAse Diagrams) and PhaComp methods were used for the prediction of phases andtheir evolutions. The microstructure of the HES-A1 alloy in as-cast, homogenized, hot rolled, annealed and aged conditionswere characterized using optical, scanning, and transmission electron microscopes as well as X-ray diffraction technique. The as-cast microstructure of HES-A1 contained 5.5% of Laves phase, which was reduced to less than 0.3% through thedevelopment of a homogenization treatment. Hot rolling with reductions up to 36% at 1015 °C did not produce any cracking,indicating a good forming potential for the new alloy. The application of double aging treatment, similar to the one forIN718 alloy, showed no presence of γʺ or formation of δ phase in the microstructure. HES-A1 has been designed with ahigher Al/(Ti + Nb) ratio and higher proportion of Al + Ti + Nb so that it could be mainly strengthened by γ′ precipitation. The average size of monomodal γ′ precipitates was smaller than that observed in conventional alloys after similar treatments.

Distribution of linear combinations of unordered and ordered components of an elliptical random vector

Ahad Jamalizadeh,H. Mahmoodian,A. Pourdarvish,N. Balakrishnan 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.2

In this paper, by considering a (k + n)-dimensional random vector XT , YT T , X ∈ Rk and Y ∈ Rn, having a multivariate elliptical distribution, we derive the exact distribution of AX + LY (n), where A ∈ Rp×k, L ∈ Rp×n, and Y(n) = Y(1), Y(2), . . . , Y(n)T denotes the vector of order statistics from Y. Next, we discuss the distribution of aTX+bY(r), for r = 1, . . . ,n, a =(a1, . . . , ak)T ∈ Rk and b ∈ R. We show that these distributions can be expressed as mixtures of multivariate unified skew-elliptical distributions. Finally, we illustrate an application of the established results to stock fund evaluation.

Catecholamine-Functionalized Reduced Graphene Oxide: A Scalable Carbon Host for Stable Cycling in Lithium–Sulfur Batteries

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>

An investigation into the recovery of oxide copper from a complex copper ore using sulphidisation technique and hydroxamate and potassium amyl xanthate collectors

Ahad Zare,Asghar Azizi,Mohammad Karamoozian 한국자원공학회 2020 Geosystem engineering Vol.23 No.1

This study was aimed to increase the floatability of oxide copper from a complex copper sample. For this purpose, sulphidisation processes such as slug and controlled potential sulphidisation (CPS) and hydroxamate and potassium amyl xanthate (Z6) collectors were utilized and their results were compared with real conditions. The results indicated that about 9.46% of the recovery of oxide copper increased using 300g/t ammonium sulphide in the first step, and reached to 77.12%. Also, in this case, the recovery of sulphide copper was significantly improved. In addition, the findings demonstrated that applying 10 g/t of potassium octyl hydroxamate anionic collector, the recovery of oxide copper reached to 74.47% without any negative effect on the recovery of sulphide copper. Meanwhile, the simultaneous use of Z11 and Z6 as collector caused to increase about 3.63% of the recovery of oxide copper (71.29%). It was also found that the highest recovery of oxide copper could be obtained using CPS method and in this case, 10.34% of the oxide copper and 4.48% of the total copper improved and also the dosage of (NH4)2S decreased.

Cancer Risk Assessment Due to Natural and Fallout Activity in Some Cities of Pakistan

Ahad A.,Matiullah Matiullah,Bhatti Ijaz A.,Orfi S.D. The Korean Association for Radiation Protection 2006 방사선방어학회지 Vol.31 No.1

The measured mean activities of $^{226}Ra,\;^{232}Th,\;^{40}K\;and\;^{137}Cs$ in the soil of Bahawalpur, Bahawalnagar and Rahimyar Khan Bistricts were 32.9, 53.6, 647.4 and 1.8 Bq $kg^{-1}$. The average absorbed dose rate calculated from these activities was 74.3 nGy $h^{-1}$ and the mean annual effective dose rate was found to be 0.46 mSv $y^{-1}$. Absorbed doses to different body organs were derived from annual effective doses using tissue weighting factors. Radiation induced fatal cancer risks were assessed by using ICRP 60 Model. Estimations incurred 184deaths per year due to cancer.

Determination of Mefenamic Acid in Human Urine by Means of Two Spectroscopic Methods by Using Cloud Point Extraction Methodology as a Tool for Treatment of Samples

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.