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.

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.

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>

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>

Interaction of Glucagon G-Protein Coupled Receptor with Known Natural Antidiabetic Compounds: Multiscoring <i>In Silico</i> Approach

Baig, M. H.,Ahmad, K.,Hasan, Q.,Khan, M. K. A.,Rao, N. S.,Kamal, M. A.,Choi, I. Hindawi Publishing Corporation 2015 Evidence-based Complementary and Alternative Medic Vol.2015 No.-

<P>Glucagon receptor (GCGR) is a secretin-like (class B) family of G-protein coupled receptors (GPCRs) in humans that plays an important role in elevating the glucose concentration in blood and has thus become one of the promising therapeutic targets for treatment of type 2 diabetes mellitus. GCGR based inhibitors for the treatment of type 2 diabetes are either glucagon neutralizers or small molecular antagonists. Management of diabetes without any side effects is still a challenge to the medical system, and the search for a new and effective natural GCGR antagonist is an important area for the treatment of type 2 diabetes. In the present study, a number of natural compounds containing antidiabetic properties were selected from the literature and their binding potential against GCGR was determined using molecular docking and other<I> in silico</I> approaches. Among all selected natural compounds, curcumin was found to be the most effective compound against GCGR followed by amorfrutin 1 and 4-hydroxyderricin. These compounds were rescored to confirm the accuracy of binding using another scoring function (<I>x</I>-score). The final conclusions were drawn based on the results obtained from the GOLD and <I>x</I>-score. Further experiments were conducted to identify the atomic level interactions of selected compounds with GCGR.</P>

Treatment of Wilms’ nephroblastoma cancer cells via EGFR targeting of dactinomycin loaded DNA-nanowires

Baig Mirza Muhammad Faran Ashraf,Zhang Chengfei,Akhtar Muhammad Furqan,Saleem Ammara,Nisar Naveed 한국약제학회 2021 Journal of Pharmaceutical Investigation Vol.51 No.2

Purpose Dactinomycin (DCTM) is a highly cytotoxic hydrophobic drug requiring robust nanomaterials for uniformed water dispersion and safe delivery to tumor site avoiding exposure to healthy cells. Methods DNA triangulation produces sturdier two-dimensional nanostructures through the polymerization of DNA-triangles by sticky ends cohesion in the form of DNA-nanosheets. The curvature of the B-form (right twisted) DNA causes the coiling of the DNA-nanosheets into DNA-nanowires (D-NWs) structures. DNA-triangles scaffolded by the short circular templates (84-NT) are stiffer in topology giving rise to compact D-NWs for DCTM loading, and cellular delivery. The PAGE gel analysis was performed to assess the polymerization of the DNA-triangles to observe restricted electrophoretic mobility, and attainment of a single sharp band. The morphology and compactness of the D-NWs were confirmed by the AFM analysis and confocal imaging. Epidermal growth factor (EGF) functionalization of the D-NWs was performed through amide chemistry using amino-modified DNA strands reacting with the carboxylic group of EGF for EGFR targeting. EGFR is highly expressed on NB-OK-1 Wilms’ tumor nephroblastoma cancer cells. DCTM loading onto D-NWs was carried out through intercalation between the base pairs of GC rich DNA duplex by physical mixing/incubation, and was confirmed through the UV peak shift analysis and confocal imaging. Cell internalizations and the cytotoxic effects were monitored via confocal imaging, MTT assay, and flow cytometry. Results AFM images of the synthesized D-NWs showed that polymerization of DNA-triangles was successful with the length ranging from 4 to 6 μm, and width ranging from 80 to 120 nm. EGF functionalization was confirmed through the confocal microscopy after labeling EGF with the FITC hook conjugating dye. The slight UV shift (> 15 nm) confirmed DCTM loading onto D-NWs. Blank D-NWs showed biocompatibility to the cells at different (low to high) concentrations (10 μM to 640 μM). MTT assay revealed that DCTM loaded D-NWs showed a dose-dependent (0.25–128 nM) decrease in cell viability. Conclusion EGF functionalized D-NWs effectively targeted the EGFR rich NB-OK-1 cancer cells compared to the control HEK293/D75 cells lacking EGFR (receptors). By these results, we can expect similar site-specific targeted treatment if administered systemically.

Role of a highly conserved proline-126 in ThDP binding of Mycobacterium tuberculosis acetohydroxyacid synthase

Baig, I.A.,Gedi, V.,Lee, S.C.,Koh, S.H.,Yoon, M.Y. IPC Science and Technology Press ; Elsevier Scienc 2013 Enzyme and microbial technology Vol.53 No.4

Acetohydroxyacid synthase (AHAS) of Mycobacterium tuberculosis is a promising target for the development of anti-tuberculosis agents. With the absence of an available bacterial AHAS crystal structure, that of M. tuberculosis, site-directed mutagenesis has been a useful tool for determining its structural and functional features. In this study, a highly conserved proline residue (P126 of M. tuberculosis AHAS) was selected, and the possible role was evaluated by site-directed mutagenesis. P126 was replaced by valine, threonine, alanine, and glutamate to yield P126V, P126T, P126A, and P126E, respectively. All variants were expressed in their soluble forms in Escherichia coli and purified to near homogeneity. The molecular mass (SDS-PAGE) of the purified variants was ~68kDa, which is similar to that of wild-type AHAS. The P126V, P126T, and P126A variants exhibited significantly lower activity than wild-type AHAS, whereas P126E was inactive under the tested assay conditions. Furthermore, the P126V and P126T variants showed a significantly decreased preference toward pyruvate and ThDP as substrate and cofactor respectively, whereas the P126A showed similar kinetics to that of wild-type AHAS. Like in AHAS from yeast Saccharomyces cerevisiae (PDB ID: 1N0H), residue P126 is located in the ThDP binding pocket of M. tuberculosis AHAS homology model. Collectively, these results suggest that the conserved P126 plays a significant role in the ThDP binding of M. tuberculosis AHAS.

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>

Use of Platelet-Rich Plasma in Treating Low Back Pain: A Review of the Current Literature

Baig Mirza Zain,Abdullah Umm E Hani,Muhammad Aun,Aziz Abeer,Syed Maryam Jamil,Darbar Aneela 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.1

Low back pain (LBP) is a common problem encountered by physicians. It is a considerable cause of morbidity and socioeconomic loss and is one of the most expensive musculoskeletal disorders. Conventional treatments include bed rest, analgesics, therapeutic exercises, lumbar or caudal epidural corticosteroids, and surgery. Several new biological therapies are being investigated for use in LBP and one of these is platelet-rich plasma (PRP). In this article, we summarize the current literature published on PRP concerning its composition, classification, and application in LBP. We believe our review will prove useful to clinicians and academics alike, interested in new developing therapies for LBP.

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>