초내열합금 B1900의 미세조직과 인장특성에 미치는 고온노출의 영향

김인수,최백규,서성문,조창용 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.7

Influence of thermal exposure on microstructural evolution and tensile properties of Ni-base superalloy B1900 has been investigated. Phase transformations during thermal exposure and their effects on tensile behavior of the alloy have been analyzed by microstructural observations. Considerable amount of acicular type M_(6)C carbide precipitated in the interdendritic regions (including γ/γ' eutectic) and in the vicinity of MC carbide as a result of thermal exposure above 871°C. Thermal exposure also assisted precipitation of small discrete M_(23)C_(6) carbide which is hard to be found in the alloy. Thermal exposure deteriorated tensile properties of the alloy. The effect of M_(6)C precipitation on the tensile properties of the alloy is not clear. However, degradation of tensile properties of the alloy is primarily attributed to the coarsening of y' phase during thermal exposure. While the localized deformation bands were observed in the as-cast tensile specimen due to shearing of γ' particle, dislocation network formed at γ/γ'interface in the thermally exposed tensile specimen.

Interfering PLD1-PED/PEA15 interaction using self-inhibitory peptides: An <i>in silico</i> study to discover novel therapeutic candidates against type 2 diabetes

Baig, Mohammad Hassan,Kausar, Mohd Adnan,Husain, Fohad Mabood,Shakil, Shazi,Ahmad, Irfan,Yadav, Brijesh S.,Saeed, Mohd Elsevier 2019 Saudi journal of biological sciences Vol.26 No.1

<P><B>Abstract</B></P> <P>Diabetes type 2 (T2D) is a very complex disorder with a large number of cases reported worldwide. There are several reported molecular targets which are being used towards drug design. In spite of extensive research efforts, there is no sure shot treatment available. One of the major reasons for this failure or restricted success in T2D research is the identification of a major/breakthrough therapeutic target responsible for the progression of T2D. It has been well documented that one of the major causes mediating the insulin resistance is the interaction of PLD1 with PED/PEA15. Herein, we have performed <I>in silico</I> experiments to investigate the interaction between PLD1 with PED/PEA15. Furthermore, this study has explored pertinent molecular interactions involving the self-derived peptides. The peptides identified in this study are found to be capable of restricting the interaction of these two proteins. Accordingly, the study suggests that the “self-derived peptides” could be used as promising therapeutic candidate(s) against T2D.</P>

Water vapor transport properties of interfacially polymerized thin film nanocomposite membranes modified with graphene oxide and GO-TiO₂ nanofillers

Baig, Muhammad Irshad,Ingole, Pravin G.,Jeon, Jae-deok,Hong, Seong Uk,Choi, Won Kil,Lee, Hyung Keun Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.373 No.-

<P><B>Abstract</B></P> <P>Graphene oxide (GO) and its composite with TiO<SUB>2</SUB> (GT) were utilized as nano-filler materials to prepare highly permeable and water vapor selective nanocomposite membranes. The nano-fillers were characterized using different analytical tools to determine their physicochemical properties. Nanocomposite membranes were prepared by dispersing the nano-fillers in aqueous phase monomer solution for interfacial polymerization reaction on the inner surface of Polysulfone hollow fiber membrane. Surface morphology and bonding chemistry of the nanocomposite membrane was analyzed using various analytical tools. The two types of nano-fillers were compared for their compatibility with the polyamide matrix, and consequently, the water vapor separation performance of the resulting membrane. Results revealed that both the nano-fillers are firmly attached to the polyamide layer via hydrogen and covalent bonds. GT based membranes have higher surface roughness and better hydrophilicity as compared to GO. In addition, GT membranes have more carboxyl groups and lesser degree of cross-linking due to the interference with interfacial polymerization reaction. This leads to a higher permeance (2820 GPU) and a water vapor/nitrogen selectivity when compared to other TFN membranes reported in literature. The nano-fillers act as active sites for preferential transport of water vapor molecules through the membrane thereby, significantly improving water vapor permeance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> GO and GO-TiO<SUB>2</SUB> nanofillers were incorporated in polyamide nanocomposite membrane. </LI> <LI> Improved water vapor permeance was obtained from GO and GO-TiO<SUB>2</SUB> nanofillers incorporated TFN membranes. </LI> <LI> Highly hydrophilic TFN membranes were obtained for water vapor separation. </LI> <LI> GO-TiO<SUB>2</SUB> shows superior water vapor permeance than GO. </LI> <LI> Functionalized GO could improve water vapor permeation even further. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>GO and GO-TiO<SUB>2</SUB> incorporation in TFN membrane by interfacial polymerization for excellent water vapor separation performance.</P> <P>[DISPLAY OMISSION]</P>

Development of carboxylated TiO₂ incorporated thin film nanocomposite hollow fiber membranes for flue gas dehydration

Baig, M.I.,Ingole, P.G.,Choi, W.K.,Park, S.R.,Kang, E.C.,Lee, H.K. Elsevier Scientific Pub. Co 2016 Journal of membrane science Vol.514 No.-

In this work, thin film nanocomposite (TFN) membranes for water vapor removal have been fabricated by incorporation of carboxylated TiO<SUB>2</SUB> nanoparticles in the polyamide membrane matrix. Surface of pure TiO<SUB>2</SUB> was modified to introduce functional groups on the TiO<SUB>2</SUB> surface and increase the hydrophilicity of the nanoparticles. Modified nanoparticles were then homogeneously dispersed in the aqueous phase monomer (3, 5-diaminobenzoic acid) and reacted with trimesoyl chloride (TMC) to form a thin film nanocomposite membrane (TFN) on top of the polysulfone hollow fiber membrane (HFM) substrate. The carboxylation of TiO<SUB>2</SUB> was confirmed by FTIR spectra. Intrinsic properties of the TFN were analyzed by ATR-FTIR, scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle. Introduction of carboxylated TiO<SUB>2</SUB> caused a more dense and cross-linked polyamide layer due to its high binding affinity with the polyamide layer, which was also confirmed by SEM analysis. Furthermore, the addition of modified nanoparticles also increased the hydrophilicity of the TFN membrane due to excess carboxylic groups. Water vapor permeance and selectivity drastically improved due to the increased water vapor permeation paths provided by the modified nanoparticles. A maximum water vapor permeance and selectivity of 1340 GPU and 486 respectively, were obtained at optimum conditions. In addition, effect of reaction time and monomer concentration have also been studied and correlated.

Experimental Studies on the Instabilities of Viscous Fingering in a Hele - Shaw Cell

Baig, Chung Gi,Chun, Young Ho,Cho, Eun Su,Choi, Chang Kyun 한국화학공학회 2000 Korean Journal of Chemical Engineering Vol.17 No.2

When air is injected into silicone oil contained in a horizontal Hele-Shaw cell, a single air bubble forms and grows showing various interesting phenomena. In this study the effects of the bubble front velocity, air injection velocity at a nozzle, fluid properties and cell depth on the stability of the growing bubble were investigated experimentally. By using the modified capillary number involving the aspect ratio, we obtained the onset conditions of the unstable bubble. Also, the bubble width was analyzed both quantitatively and qualitatively. Before the bubble experiences splitting, the bubble front velocity is almost proportional to the air injection velocity. Therefore the latter velocity may be used in a practical sense.

Reasons and Motivations for Cigarette Smoking and Barriers against Quitting Among a Sample of Young People in Jeddah, Saudi Arabia

Baig, Mukhtiar,Bakarman, Marwan A,Gazzaz, Zohair J,Khabaz, Mohamad N,Ahmed, Tahir J,Qureshi, Imtiaz A,Hussain, Muhammad B,Alzahrani, Ali H,Al-Shehri, Ali A,Basendwah, Mohammad A,Altherwi, Fahd B,Al-Sh Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.7

Background: Cigarette smoking is one of the leading causes of death in the world. Tobacco consumption has grave negative consequences for health so that it is important to understand the reasons and motivations towards cigarette smoking and barriers against quitting smoking among the young generation for developing effective policies to control this widespread problem. Materials and Methods: This cross-sectional survey was carried out at the Faculty of Medicine, Rabigh, King Abdulaziz University, Jeddah, Saudi Arabia. A total of 438 young smokers participated from the University and the general population. Data were collected through anonymous, self-administered questionnaires in the Arabic language that contained questions about the reasons and motivations towards cigarette smoking and barriers against quitting smoking. The questionnaire also contained several questions regarding knowledge and attitude of the participants towards cigarette smoking. The data was analyzed on SPSS-16. Results: The mean age of the respondents was $22.9{\pm}3.48$, out of 438 subjects 87 (19.9%) were married, and 351 (80.1%) were unmarried, and 331 (75.6%) belonged to urban areas while 107 (24.5%) were from the rural areas. Responding to a question about a number of cigarettes smoked per day, 31% answered 11-20, 29% answered 21-30, and 25% answered 1-10. Questioned about smokers in the family, 34.5% responded more than one, with 19% for brother and 13% for father. About the reasons for not quitting smoking, 26% described lack of willpower, 25% had no reason, 22% said that people around me smoke, and 15.3% responded stress at home/work. The major motivation for smokers was smoker friends (42%), for 33.8% others, for 12% father/brother and 7.8% media. Conclusions: There are several avoidable and preventable reasons and barriers against quitting smoking. However, knowledge and attitude about smoking were good, and the majority of the smokers were well aware of the associated hazards. Therefore, there is a need to search out ways and means to help them to quit this addiction.

Development of ssDNA aptamers as potent inhibitors of Mycobacterium tuberculosis acetohydroxyacid synthase.

Baig, Irshad Ahmed,Moon, Ji-Young,Lee, Sang-Choon,Ryoo, Sung-Weon,Yoon, Moon-Young Elsevier Science Publishers B.V 2015 Biochimica et biophysica acta. Proteins and proteo Vol.1854 No.10

<P>Acetohydroxyacid synthase (AHAS) from Mycobacterium tuberculosis (Mtb) is a promising potential drug target for an emerging class of new anti-tuberculosis agents. In this study, we identify short (30-mer) single-stranded DNA aptamers as a novel class of potent inhibitors of Mtb-AHAS through an in vitro DNA-SELEX method. Among all tested aptamers, two candidate aptamers (Mtb-Apt1 and Mtb-Apt6) demonstrated the greatest inhibitory potential against Mtb-AHAS activity with IC50 values in the low nanomolar range (28.940.002 and 22.350.001nM respectively). Interestingly, inhibition kinetics analysis of these aptamers showed different modes of enzyme inhibition (competitive and mixed type of inhibition respectively). Secondary structure-guided mutational modification analysis of Mtb-Apt1 and Mtb-Apt6 identified the minimal region responsible for their inhibitory action and consequently led to 17-mer and 20-mer shortened aptamers that retained equivalent or greater inhibitory potential. Notably, a modeling and docking exercise investigated the binding site of these two potent inhibitory aptamers on the target protein and showed possible involvement of some key catalytic dimer interface residues of AHAS in the DNA-protein interactions that lead to its potent inhibition. Importantly, these two short candidate aptamers, Mtb-Apt1 (17-mer) and Mtb-Apt6 (20-mer), also demonstrated significant growth inhibition against multidrug-resistant (MDR-TB) and extensively drug-resistant (XDR-TB) strains of tuberculosis with very low MIC of 5.36μg/ml and 6.24μg/ml, respectively and no significant cytotoxicity against mammalian cell line. This is the first report of functional inhibitory aptamers against Mtb-AHAS and provides the basis for development of these aptamers as novel and strong anti-tuberculosis agents.</P>

Structural and functional significance of the highly-conserved residues in Mycobacterium tuberculosis acetohydroxyacid synthase

Baig, Irshad Ahmed,Moon, Ji-Young,Kim, Min-Seo,Koo, Bon-Sung,Yoon, Moon-Young Elsevier 2014 Enzyme and microbial technology Vol.58 No.-

<P>Mycobacterium tuberculosis AHAS is a potential target for the development of novel anti-tuberculosis agents. Silico analysis showed that conserved His84 and Gln86 residues lie in the catalytic dimer interface of M. tuberculosis AHAS. Mutational analyses of these invariants led to significant reduction in their activity with reduced affinity toward the substrate. Importantly, mutation of Gln86 to Trp abolished complete activity. Further, molecular dynamics simulation studies suggested that these residues are likely to play a key role in maintaining the Glu85 side chain in the required geometry with N1′ atom of ThDP during catalysis. In addition, substitution of essential Glu85 by Ala, Asp, and Gln led to severe drop in catalytic activity with reduced affinity toward ThDP confirming its catalytic role in M. tuberculosis AHAS.</P>

Multi-Spectroscopic Characterization of Human Serum Albumin Binding with Cyclobenzaprine Hydrochloride: Insights from Biophysical and <i>In Silico</i> Approaches

Baig, Mohammad Hassan,Rahman, Safikur,Rabbani, Gulam,Imran, Mohd,Ahmad, Khurshid,Choi, Inho MDPI 2019 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.20 No.3

<P>Cyclobenzaprine hydrochloride (CBH) is a well-known muscle relaxant that is widely used to relieve muscle spasms and other pain associated with acute musculoskeletal conditions. In this study, we elucidated the binding characteristics of this muscle relaxant to human serum albumin (HSA). From a pharmaceutical and biochemical viewpoint, insight into the structure, functions, dynamics, and features of HSA-CBH complex holds great importance. The binding of CBH with this major circulatory transport protein was studied using a combination of biophysical approaches such as UV-VIS absorption, fluorescence quenching, and circular dichroism (CD) spectroscopy. Various <I>in silico</I> techniques, molecular docking and molecular dynamics, were also used to gain deeper insight into the binding. A reduction in the fluorescence intensities of HSA-CBH complex with a constant increase in temperature, revealed the static mode of protein fluorescence quenching upon CBH addition, which confirmed the formation of the HSA-CBH ground state complex. The alteration in the UV-VIS and far-UV CD spectrum indicated changes in both secondary and tertiary structures of HSA upon binding of CBH, further proving CBH binding to HSA. The analysis of thermodynamic parameters ∆H° and ∆S° showed that binding of CBH to HSA was dominated by intermolecular hydrophobic forces. The results of the molecular docking and molecular dynamics simulation studies also confirmed the stability of the complex and supported the experimental results.</P>

Text writing in the air

Baig, Faisal,Khan, Muhammad Fahad,Beg, Saira 한국정보디스플레이학회 2013 Journal of information display Vol.14 No.4

This paper presents a real-time video-based pointing method that allows the sketching and writing of English text over air in front of a mobile camera. The proposed method has two main tasks. First, it tracks the colored fingertip in the video frames and then applies English optical character reorganization over the plotted images to recognize the written characters. Moreover, the proposed method provides a natural human-system interaction without requiring a keypad, stylus, pen, glove, or any other device for character inputs. For the experiments, an application was developed using OpenCv with the JAVA language. The proposed method was tested on a Samsung Galaxy3 android mobile phone. The proposed algorithm showed an average accuracy rate of 92.083% when tested for different shaped alphabets. Here, more than 3000 different shaped characters were used. The proposed system is a software-based approach and is relevantly very simple, fast, and easy to use. It does not require sensors or any hardware other than a camera and red tape, and is applicable to all disconnected languages. It has one issue, though it is color-sensitive in that the existence of any red-colored object in the background before the start of and during the character writing can lead to false results.