Hydrophilic nanofibrous structure of polylactide; fabrication and cell affinity

Bhattarai, Shanta Raj,Bhattarai, Narayan,Viswanathamurthi, Periasamy,Yi, Ho Keun,Hwang, Pyoung Han,Kim, Hak Yong Wiley Publishers 2006 Journal of Biomedical Materials Research Part A Vol. No.

<P>Microstructure and architecture of the scaffolds along with the surface chemistry exert profound effect on biological activity (cell distribution, proliferation, and differentiation). For the biological activity, scaffolds in tissue engineering have been widely designed. The objective of this study was to develop hydrophilic nanofibrous structure of polylactides (PLLA) polymer in the form of nonwoven mat by electrospinning technique, and further evaluate the fibroblast NIH3T3 cell proliferation, morphology, and cell–matrix interaction. Hydrophilicity of the PLLA fibers was improved by adding small fraction of low molecular weight polyethylene glycol (PEG) into the electrospinning solution. Four different ratio types (100/0, 80/20, 70/30, and 50/50) of PLLA/PEG electrospun matrices were fabricated, and the pore characteristics, tensile properties, contact angle, and hydrolytic degradation were observed. Furthermore, scanning electron microscope (SEM) and fluorescence actin staining images were used for micro-observation of cell–matrix interaction and cell morphology. It was found that the electrospun mat of PLLA/PEG (80/20), composed of fibers with diameters in the range 540–850 nm, majority of pore diameter less than 100 μm, tensile strength 8 MPa, elongation 150%, porosity more than 90%, and improved hydrophilicity with slow hydrolytic degradation, is favorable for biological activity of NIH3T3 fibroblast cell. Based on these results, the correct composition of PLLA and PEG in the porous electrospun matrix (i.e., PLLA/PEG (80/20)) will be a better candidate rather than other compositions of PLLA/PEG as well as hydrophobic PLLA for application in tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006</P>

Amphiphilic triblock copolymer poly(p-dioxanone-co-L-lactide)-block-poly(ethylene glycol), enhancement of gene expression and inhibition of lung metastasis by aerosol delivery

Bhattarai, S R,Kim, S Y,Jang, K Y,Yi, H K,Lee, Y H,Bhattarai, N,Nam, S-Y,Lee, D Y,Kim, H Y,Hwang, P H Nature Publishing Group 2007 Gene Therapy Vol.14 No.6

<P>We describe the development of an aerosol system for topical gene delivery to the lungs of C57BL/6 mice. This system is based on the combination of the commercial cationic lipid Lipofectin with a novel amphiphilic triblock copolymer, poly(p-dioxanone-co-L-lactide)-block-poly(ethylene glycol) (PPDO/PLLA-b-PEG, and abbreviated in the text as polymeric micelles). After optimizing conditions for DNA delivery to the lungs of mice using the combination of polymeric micelles with Lipofectin and LacZ DNA, we used the Lipofectin/polymeric micelle system to deliver the tumor suppressor gene PTEN to the lungs of C57BL/6 mice bearing the B16-F10 melanoma. Lipofectin/PTEN/polymeric micelles significantly improved gene expression of PTEN in the lungs of mice with no evidence of cell toxicity or acute inflammation. Importantly, lung metastasis, as measured by lung weight, was significantly reduced (P<0.001), as were total tumor foci in the lungs (P<0.001) and size of individual tumor nodules in animals treated with Lipofectin/PTEN/polymeric micelles compared with control animals. Survival time was also extended. These results suggest that the Lipofectin/polymeric micelle system is appropriate for enhancing gene delivery in vivo and that it can be applied as a non-invasive gene therapy for lung cancer.</P>

Effect of long term high altitude exposure on cardiovascular autonomic adjustment during rest and post-exercise recovery

Prem Bhattarai,Bishnu H. Paudel,Dilip Thakur,Balkrishna Bhattarai,Bijay Subedi,Rita Khadka 대한직업환경의학회 2018 대한직업환경의학회지 Vol.30 No.-

Background: Despite the successful adaptation to high altitude, some differences do occur due to long term exposure to the hypoxic environment. The effect of long term high altitude exposure on cardiac autonomic adjustment during basal and post-exercise recovery is less known. Thus we aimed to study the differences in basal cardiac autonomic adjustment and its response to exercise in highlanders and to compare it with lowlanders. Methods: The study was conducted on 29 healthy highlander males who were born and brought up at altitude of 3000 m and above from the sea level, their cardiac autonomic adjustment was compared with age, sex, physical activity and ethnicity-matched 29 healthy lowlanders using Heart Rate Variability (HRV) during rest and recovery from sub-maximal exercise (3 m step test). Intergroup comparison between the highlanders and lowlanders and intragroup comparison between the rest and the postexercise recovery conditions were done. Results: Resting heart rate and HRV during rest was comparable between the groups. However, heart rate recovery after 3 min step test was faster in highlanders (p 〈 0.05) along with significantly higher LF power and total power during the recovery phase. Intragroup comparison of highlanders showed higher SDNN (p 〈 0.05) and lower LF/HF ratio (p〈 0.05) during recovery phase compared to rest which was not significantly different in two phases in lowlanders. Further highlander showed complete recovery of RMSSD, NN50, pNN50 and HF power back to resting level within five minutes, whereas, these parameters failed to return back to resting level in lowlanders within the same time frame. Conclusion: Highlanders completely recovered back to their resting state within five minutes from cessation of step test with parasympathetic reactivation; however, recovery in lowlanders was delayed.

Application of CE-QUAL-W2 [v3.2] to Andong Reservoir: Part I: Simulations of Hydro-thermal Dynamics, Dissolved Oxygen and Density Current

Bhattarai, Prasid Ram,Kim, Yoon-Hee,Heo, Woo-Myoung The Korean Society of Limnology 2008 생태와 환경 Vol.37 No.1

A two-dimensional (2D) reservoir hydrodynamics and water quality model, CE-QUAL-W2, is employed to simulate the hydrothermal behavior and density current regime in Andong Reservoir. Observed data used for model forcing and calibration includes: surface water level, water temperature, dissolved oxygen and suspended solids concentration. The model was calibrated to the year of 2003 and verified with continuous run from 2000 till 2004. Without major adjustments, the model accurately simulated surface water levels including the events of large storm. Deep-water reservoirs, like Andong Reservoir, located in the Asian Monsoon region begin to stratify in summer and overturn in fall. This mixing pattern as well as the descending thermocline, onset and duration of stratification and timing of turnover phenomenon were well reproduced by the Andong Model. The temperature field and distinct thermocline are simulated to within $2^{\circ}C$ of observed data. The model performed well in simulating not only the dissolved oxygen profiles but also the metalimnetic dissolved minima phenomenon, a common1y occurring phenomenon in deep reservoirs of temperate regions. The Root Mean Square Error (RMSE) values of model calibration for surface water elevation, temperature and dissolved oxygen were 0.0095 m, $1.82^{\circ}C$, and $1.13\;mg\;L^{-1}$, respectively. The turbid storm runoff, during the summer monsoon, formed an intermediate layer of about 15 m thickness, moved along the metalimnion until being finally discharged from the dam. This mode of transport of density current, a common characteristic of various other large reservoirs in the Asian summer monsoon region, was well tracked by the model.

Somatostatin Inhibition of Gonadotropin-Releasing Hormone Neurons in Female and Male Mice

Bhattarai, Janardhan P.,Kaszá,s, Attila,Park, Seon Ah,Yin, Hua,Park, Soo Joung,Herbison, Allan E.,Han, Seong Kyu,Á,brahá,m, Istvá,n M. The Endocrine Society 2010 Endocrinology Vol.151 No.7

Antioxidant activity of Sanionia uncinata, a polar moss species from King George Island, Antarctica

Bhattarai, Hari Datta,Paudel, Babita,Lee, Hyoung Seok,Lee, Yoo Kyung,Yim, Joung Han John Wiley Sons, Ltd. 2008 Phytotherapy research Vol.22 No.12

<P>Antioxidant agents counter reactive oxygen species (ROS) and can be used in cosmetic and medicinal applications. The goal of this study was to evaluate the antioxidant activity of an Antarctic moss species from King George Island (Antarctica), tentatively designated as KSJ-M5. On the basis of morphological characteristics, KSJ-M5 was identified as Sanionia uncinata (Hedw.) Loeske (Amblystegiaceae). The identification was confirmed by comparing the partial sequence of the ITS (internal transcribed spacer) region with that in GenBank. The antioxidant activity of an ethanol extract of KSJ-M5 was evaluated by analyzing its reducing power, superoxide scavenging activity, ABTS [2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] cation scavenging activity, and DPPH (1,1-diphenyl-2-picrylhydrazyl) free-radical scavenging activity. The reducing power of 1 mg of KSJ-M5 extract was equivalent to 31.9 ± 0.9 µg (Mean ± SD, n = 3) of the commercial standard, BHT (butylated hydroxytoluene). IC<SUB>50</SUB> values of the KSJ-M5 extract for DPPH free-radical scavenging activity, superoxide scavenging activity, and ABTS cation scavenging activity were found as 356 ± 26.8 µg/mL, 466.2 ± 43.4 µg/mL, and 181.3 ± 12.2 µg/mL, respectively. The total phenolic content in 1 mg of KSJM5 extract was equivalent to 12.7 ± 2.7 µg of pyrocatechol. These results clearly showed that KSJ-M5 could be an important source of natural antioxidant agents for improved medicinal and cosmetic applications. Copyright © 2008 John Wiley & Sons, Ltd.</P>

Application of Plasma to Fabricate Carbon Coated Ni₂P Nanocomposites for High Rate and High Stability Lithium Ion Batteries Anode Material

( Bhattarai Roshan Mangal ),( Sudhakaran M. S. P ),( Md. Mokter Hossain ),( Saud Shirjana ),목영선 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Carbon-coated Ni₂P nanocomposites have been fabricated using an atmospheric plasma deposition method in a planar DBD set up. Planar DBD plasma has powered at low power, which can produce a thin layer of carbon. Obtained nanocomposites have been characterized using different approaches like XRD analysis, FE-SEM, EDS elemental mapping, Raman Spectroscopy, and Fourier Transform Infrared Spectrophotometry. These nanocomposites as anode materials for lithium- ion batteries (LIBs) should exhibit excellent rate capability and high stable cycling performances compared to its pristine electrode Ni₂P. CR2032 cell has been fabricated and put for the electrochemical characterization process. Electrochemical impedance spectroscopy and Cyclic Voltammetry (CV) analysis demonstrate the enhanced rate performance and improved cycling stability of the carbon coated Ni₂P nanocomposites.

Potentiation of NMDA receptors by Withania somnifera on hippocampal CA1 pyramidal neurons.

Bhattarai, Janardhan Prasad,Park, Soo Joung,Han, Seong Kyu Institute for Advanced Research in Asian Science a 2013 The American journal of Chinese medicine Vol.41 No.3

<P>In Ayurveda,Withania somnifera (WS) is used as a medicine to maintain mental and physical health as well as to enhance memory. In this study, the methanolic extract of WS(mWS) was tested for its electrical influence on hippocampal CA1 pyramidal neurons using a patch clamp technique. In current clamp mode under a high chloride pipette solution, mWS (400 ng/μl) induced remarkable membrane depolarization (9.75 2.54 mV, n = 6) of CA1 neurons. The mWS-induced depolarization was dose-dependent, reproducible, and persistent in the presence of 0.5 μM tetrodotoxin (TTX, 10.17 0.04 mV, n = 6). In voltage clamp mode (holding potential = -60 mV), mWS induced a dose-dependent non-desensitizing inward current that persisted in the presence of TTX (0.5 μM), suggesting that the response induced by mWS was purely a postsynaptic event. Interestingly, these inward currents were partially blocked by strychnine, a glycine receptor blocker. Further, mWS potentiated the NMDA response in hippocampal CA1 neurons at low concentrations. Overall, these results suggest that there are compounds in WS with possible glycine mimetic activities, which may be potential targets for inducing memory consolidation in hippocampal CA1 neurons.</P>

Impact of Organizational Politics on Employees' Behavioral Outcomes: The Role of Social Astuteness

BHATTARAI, Ganesh Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

Employers and employees are seriously suffering from perceived organizational politics exhibited in the workplace, and they are searching for remedial ways. The current study was carried out to measure the (i) effects of the employees' perceived organizational politics on their behavioral outcomes, and (b) the remedial role of employees' social astuteness in the relationship of their perceived organizational politics to behavioral outcomes (i.e., work engagement and turnover intention). Seven hundred and twenty-five employees working in Nepalese A graded banks were surveyed to collect the perceptual cross-sectional data. The data were quantitatively analyzed, adopting the deducting reasoning approach. Regression analysis revealed that (i) perceived organizational politics negatively impacted on work engagement and positively impacted on turnover intention, (ii) social astuteness moderated the relationship between perceived organizational politics and employees' behavioral outcome. Moreover, perceived organizational politics' detrimental impact was less severe for employees who possess high social astuteness as compared to those who have less social astuteness. The remedial effect of social astuteness was measured more useful for high organizational politics perceiver than for low perceiver. A number of theoretical and practical implications are suggested to improve the employees' behavioral outcomes from the detrimental impact of perceived corporate politics.

Homology Modeling and Docking Studies of Streptomyces peucetius CYP147F1 as Limonene Hydroxylase

( Bhattarai Saurabh ),( Kwangkyoung Liou ),( Tae Jin Oh ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.7

Homology modeling of Streptomyces peucetius CYP147F1 was constructed using three cytochrome P450 structures, CYP107L1, CYPVdh, and CYPeryF, as templates. The lowest energy SPCYP147F1 model was then assessed for stereochemical quality and side-chain environment by Accelrys Discovery Studio 3.1 software. Further activesite optimization of the SPCYP147F1 was performed by molecular dynamics to generate the final SPCYP147F1 model. The substrate limonene was then docked into the model. The model-limonene complex was used to validate the active-site architecture, and functionally important residues within the substrate recognition site were identified by subsequent characterization of the secondary structure. The docking of limonene suggested that SPCYP147F1 would have broad specificity with the ligand based on the two different orientations of limonene within the active site facing to the heme. Limonene with C7 facing the heme with distance of 3.4 A from the Fe was predominant.