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E kim

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All four known cyclic adducts formed in DNA by the vinyl chloride metabolite chloroacetaldehyde are released by a human DNA glycosylase

Proceedings of the National Academy of Sciences, 1994

We have previously reported that human cells and tissues contain a 1,N6-ethenoadenine (epsilon A)... more We have previously reported that human cells and tissues contain a 1,N6-ethenoadenine (epsilon A) binding protein, which, through glycosylase activity, releases both 3-methyladenine (m3A) and epsilon A from DNA treated with methylating agents or the vinyl chloride metabolite chloroacetaldehyde, respectively. We now find that both the partially purified human epsilon A-binding protein and cell-free extracts containing the cloned human m3A-DNA glycosylase release all four cyclic etheno adducts--namely epsilon A, 3,N4-ethenocytosine (epsilon C), N2,3-ethenoguanine (N2,3-epsilon G), and 1,N2-ethenoguanine (1,N2-epsilon G). Base release was both time and protein concentration dependent. Both epsilon A and epsilon C were excised at similar rates, while 1,N2-epsilon G and N2,3-epsilon G were released much more slowly under identical conditions. The cleavage of glycosyl bonds of several heterocyclic adducts as well as those of simple methylated adducts by the same human glycosylase appears ...

Trigger electronics upgrade of PHENIX muon tracker

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2013

The Relativistic Heavy Ion Collider (RHIC) at Brookhave National Laboratory (BNL) provides a uniq... more The Relativistic Heavy Ion Collider (RHIC) at Brookhave National Laboratory (BNL) provides a unique opportunity to collide polarized protons at high energies. One of the highlights of the polarized proton program at √ s = 500 GeV is the direct measurement of sea quark contribution to the proton spin via W-boson production by measuring parity violating single spin asymmetry. A new trigger electronics on forward muons which specializes in W-boson detection was developed for the PHENIX experiment. The trigger was installed as an additional electronic circuit which is connected in parallel to existinig cathode readout elecctronics of the muon tracking chamber.

Planar Patch based 3D Environment Modeling with Stereo Camera

RO-MAN 2007 - The 16th IEEE International Symposium on Robot and Human Interactive Communication, 2007

We present two robust and novel algorithms to model a 3D environment using both intensity and ran... more We present two robust and novel algorithms to model a 3D environment using both intensity and range data provided by an off-the-shelf stereo camera. The main issue we need to address is that the output of the stereo system is both sparse and noisy. To overcome this limitation,, we detect planar patches in the environment by region segmentation in 2D and plane extraction in 3D. The extracted planar patches are used not only to represent the workspace, but also to fill holes in range data. We also suggest a new planar patch based scan matching algorithm to register multiple views, and to incrementally augment the description of the 3D workspace in a sequence of scenes. Experimental results on real data show that planar patch segmentation and 3D scene registration for environment modeling can be robustly achieved by the proposed approaches.

A dual hypoxic marker technique for measuring oxygenation change within individual tumors

British Journal of Cancer, 1998

Rodent tumour models have been the 'workhorse' for tumour oxygenation research and for investigat... more Rodent tumour models have been the 'workhorse' for tumour oxygenation research and for investigating radiobiological hypoxic fraction. Because of the intertumour heterogeneity of blood flow and related parameters, most studies have pooled information derived from several different tumours to establish the statistical significance of specific measurements. But it is the oxygenation status of and its modulation in individual tumours that has important prognostic significance. In that regard, the bioreducible hypoxic marker technique was tested for its potential to quantify oxygenation changes within individual tumours. f-D-lodinated azomycin galactoside (IAZG) and P-Diodinated azomycin xylopyranoside (IAZXP) were each radiolabelled with lodine-125 and iodine-131 for measurements of animal tumour oxygenation. The tumour-blood (T/B) ratio of marker radioactivity in mice after the renal excretion of unbound marker (at 3 h and longer times) had been shown to be proportional to radiobiological hypoxic fraction. When markers labelled with both radioisotopes were administered simultaneously to EMT-6 tumour-bearing scid mice, T/B ratios were found to vary by up to 300% between different tumours, with an average intratumour variation of only-4%. When the markers were administered 2.5-3.0 h apart, changes in T/B ratios of 8-25% were observed in 10 out of 28 (36%) tumours. Changes to both higher and lower hypoxic fraction were observed, suggestive of acute or cycling hypoxia. When 0.8 mg g-1 nicotinamide plus carbogen was administered to increase tumour oxygenation, reductions in T/B ratios (mean AT/B-38%) were observed in all tumours. Similar results were obtained with Dunning rat prostate carcinomas growing in Fischer X Copenhagen rats whose T/B ratios of IAZG and radiobiological hypoxic fractions are significantly lower. These studies suggest that fluctuating hypoxia can account for at least 25% of the total hypoxic fraction in some tumours and that correlations between bioreducible marker avidity and related tumour properties will be optimal when the independent assays are performed over the same time period. This dual hypoxic marker technique should prove useful for investigating both spontaneous and induced oxygenation changes within individual rodent tumours.

Aquatic Toxicity Comparison of Silver Nanoparticles and Silver Nanowires

BioMed research international, 2015

To better understand the potential ecotoxicological impact of silver nanoparticles (AgNPs) and si... more To better understand the potential ecotoxicological impact of silver nanoparticles (AgNPs) and silver nanowires (AgNWs) released into freshwater environments, the toxicities of these nanomaterials were assessed and compared using Organization for Economic Cooperation and Development (OECD) test guidelines, including a "Daphnia sp., acute immobilization test,"…

Passive L-band H polarized microwave emission during the corn growth cycle

2011 IEEE International Geoscience and Remote Sensing Symposium, 2011

L-band radiometry is recognized as a technique with a significant potential for providing spatial... more L-band radiometry is recognized as a technique with a significant potential for providing spatial and temporal soil moisture variations [1, 2]. As a result, satellite missions dedicated to global soil moisture monitoring have been proposed. A 2D-interferometric L-band radiometer has recently been launched onboard the European SMOS (Soil moisture and Ocean Salinity) satellite, [3], and the NASA is in preparation of a similar suite of microwave instruments as a part of the Aquarius and SMAP (Soil Moisture Active/Passive missions, [4] which have anticipated launch dates in 2011 and 2014, respectively. The reliability of soil moisture products derived from these microwave observations will depend, at least in part, on the effectiveness of accounting for vegetation and surface roughness impacts. From a combined active/passive microwave remote sensing campaign conducted in 2002, hourly L-band H polarized T B (Brightness temperature) measurements are available for five episodes (> 2.5 days) distributed over the corn growth cycle. These measurements were collected at five incidence angles and three azimuth angles relative to crop row orientation. A labor intensive ground characterization took place on a weekly basis in the direct proximity of the footprints and, at some distance (<100 m), a suite of automated instruments were available to support the microwave data sets. In this investigation, the soil moisture and temperatures measured at preset time intervals have been utilized as input for the τ-ω (Tau-Omega) model to reproduce the measured T B cycles. Via calibration of the model's vegetation and roughness parameterizations, the impact of the changing canopy structure throughout the season and soil moisture dependence of the h r are evaluated. This study shows (see Figure 1) that the empirical parameter b, defining the optical depth or canopy opacity (τ), and its dependence towards the incidence and azimuth angles change both during the growth cycle. The b found for the early growth stage is about three times larger than expected based on the literature, while near peak biomass and at senescence its value is about half. The latter is mainly caused by assuming the scattering within canopy to be negligible by setting the single scattering albedo (ω) equal to zero. The larger b at the beginning of the growth cycle is consistent with a previous report by Wigneron et al. [5].

Three-dimensional structure of Bax-mediated pores in membrane bilayers

Cell death & disease, 2013

B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax) is a member of the Bcl-2 protein family havi... more B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax) is a member of the Bcl-2 protein family having a pivotal role in triggering cell commitment to apoptosis. Bax is latent and monomeric in the cytosol but transforms into its lethal, mitochondria-embedded oligomeric form in response to cell stress, leading to the release of apoptogenic factors such as cytochrome C. Here, we dissected the structural correlates of Bax membrane insertion while oligomerization is halted. This strategy was enabled through the use of nanometer-scale phospholipid bilayer islands (nanodiscs) the size of which restricts the reconstituted system to single Bax-molecule activity. Using this minimal reconstituted system, we captured structural correlates that precede Bax homo-oligomerization elucidating previously inaccessible steps of the core molecular mechanism by which Bcl-2 family proteins regulate membrane permeabilization. We observe that, in the presence of BH3 interacting domain death agonist (Bid) BH3 ...

Modeling of brain D2 receptor occupancy-plasma concentration relationships with a novel antipsychotic, YKP1358, using serial PET scans in healthy volunteers

Clinical pharmacology and therapeutics, 2007

YKP1358 is a novel serotonin (5-HT(2A)) and dopamine (D(2)) antagonist that, in preclinical studi... more YKP1358 is a novel serotonin (5-HT(2A)) and dopamine (D(2)) antagonist that, in preclinical studies, fits the general profile of an atypical antipsychotic. We conducted a D(2) receptor occupancy study with YKP1358 in healthy volunteers using positron emission tomography (PET) to measure the D(2) receptor occupancy of YKP1358 and to characterize its relationship to plasma drug concentrations. A single oral dose, parallel group, dose-escalation (100, 200, and 250 mg) study was performed in 10 healthy male volunteers with the PET radiotracer [(11)C]raclopride. The D(2) receptor occupancy of striatum was measured pre-dose, and at 2, 5, and 10 h after YKP1358 administration. Serial blood samples were taken for measurement of plasma YKP1358 concentrations. D(2) receptor occupancy by YKP1358 increased to 53-83% at 2 h, and then decreased afterwards, ranging from 40-64% at 5 h to 20-51% at 10 h. The YKP1358 dose-plasma concentration relationship exhibited extensive variability, but there wa...

Electrochemical Study of the Catechol-Modified Chitosan System for Clozapine Treatment Monitoring

Langmuir, 2014

This work presents a thorough electrochemical and reliability analysis of a sensing scheme for th... more This work presents a thorough electrochemical and reliability analysis of a sensing scheme for the antipsychotic clozapine. We have previously demonstrated a novel detection approach for this redox-active drug, highly effective in schizophrenia treatment, based on a catecholmodified chitosan film. The biomaterial film enables amplification of the oxidative current generated by clozapine through redox cycling. Here, we study critical electrochemical and material aspects of the redox cycling system to overcome barriers in point-of-care monitoring in complex biological samples. Specifically, we explore the electrochemical parameter space, showing that enhanced sensing performance depends on the presence of a reducing mediator as well as the electrochemical technique applied. These factors account for up to 1.75-fold and 2.47-fold signal enhancement, respectively. Looking at potential interferents, we illustrate that the redox cycling system allows for differentiation between selected redoxactive species, clozapine's structurally largely analogous metabolite norclozapine as well as the representative catecholamine dopamine. Furthermore, we investigate material stability and fouling with reuse as well as storage. We find no evidence of film fouling due to clozapine; slow overall biomaterial degradation with successive use accounts for a 2.2% absolute signal loss and can be controlled for. Storage of the redox cycling system appears feasible over weeks when kept in solution with only 0.26%/day clozapine signal degradation, while ambient air exposure of three or more days reduces performance by 58%. This study not only advances our understanding of the catechol-modified chitosan system, but also further establishes the viability of applying it toward sensing clozapine in a clinical setting. Such point-of-care monitoring will allow for broader use of clozapine by increasing convenience to patients as well as medical professionals, thus improving the lives of people affected by schizophrenia through personalized medicine.

Factors Contributing to Quality of Life in Copd in South Korea

Value in Health, 2014

reasons for self-medication, factors that influenced the choice of drug and source of drug. Resul... more reasons for self-medication, factors that influenced the choice of drug and source of drug. Results: People of all socio-demographic categories practice self-medication. A total of 76.8% of the respondents indulged in self-medication practices. Of which, 33.0% used the medication inappropriately. The most frequently self-diagnosed illnesses or symptoms of illnesses were: GI illnesses, cough/cold and headache/fever. Of these illnesses, more than 35% were less than 24 hours duration and nearly 80% less than seven days duration of illness. The reasons given by respondents for selfdiagnosis and self-medication were non-seriousness of the illnesses, for emergency use and prior experience about the illness with similar symptoms (39.7%) and even advice of non-physician health professional (33.5%). Whatever the duration of illnesses and reasons for self-diagnosis, nearly 65% requested drugs by mentioning the names of the drugs and more than one-fifth by telling the symptoms of their illnesses. Requests for analgesics/antipyretics were very high (60%) followed by antimicrobial drugs (40%) for all reported illness. Drug requested mostly in other conditions include cold/cough suppressants, Gastro Intestinal drugs and very low for ORS. ConClusions: The level of inappropriate drug use denotes self-medication as an unhealthy option, and it therefore, should be discouraged.

Ischemic preconditioning via epsilon protein kinase C activation requires cyclooxygenase-2 activation in vitro

The signaling pathway of cyclooxygenase-2 (COX-2) induction following ischemic preconditioning (I... more The signaling pathway of cyclooxygenase-2 (COX-2) induction following ischemic preconditioning (IPC) in brain remains undefined. To determine role of COX-2 in ischemic preconditioning, we used two in vitro models: mixed cortical neuron/astrocyte cell cultures and organotypic hippocampal slice cultures. We simulated IPC by exposing cell or slice cultures to 1 h or 15 min of oxygen/glucose deprivation (OGD), respectively, 48 h prior to ischemia. To mimic ischemia in vitro, we exposed cell or slice cultures to OGD of 4 h or 45 min, respectively. In cell cultures, these experiments revealed that COX-2 induction peaked at 24 h following IPC in cell culture. Inhibition of COX-2 activation with 50 μM NS-398 (a COX-2 selective inhibitor) abolished IPC-mediated neuroprotection in both in vitro models. Next, we tested whether εPKC and ERK1/2 activation were involved in IPCmediated neuroprotection and COX-2 expression in cell culture. Cell cultures were treated with an εPKC-specific activating peptide (ψεRACK, 100 nM) for 1 h, and 48 h later were exposed to OGD. εPKC activation increased ERK1/2 phosphorylation and COX-2 induction and conferred neuroprotection similar to IPC. Additionally, inhibition of either εPKC or ERK1/2 activation abolished COX-2 expression and neuroprotection due to ischemic preconditioning. These results demonstrate a crucial role for the εPKC → ERK1/2 → COX-2 pathway in the induction of neuroprotection via ischemic preconditioning.

Double-helicity dependence of jet properties from dihadrons in longitudinally polarized p+p collisions at √s=200GeV

Physical Review D - Particles, Fields, Gravitation and Cosmology, 2010

Pesticides in Urban Multiunit Dwellings: Hazard Identification Using Classification and Regression Tree (CART) Analysis

Journal of the Air & Waste Management Association, 2008

Many units in public housing or other low-income urban dwellings may have elevated pesticide resi... more Many units in public housing or other low-income urban dwellings may have elevated pesticide residues, given recurring infestation, but it would be logistically and economically infeasible to sample a large number of units to identify highly exposed households to design interventions. Within this study, our aim was to devise a low-cost approach to identify homes in public housing with high levels of pesticide residues, using information that would allow the housing authority and residents to determine optimal strategies to reduce household exposures. As part of the Healthy Public Housing Initiative, we collected environmental samples from 42 public housing apartments in Boston, MA, in 2002 and 2003 and gathered housing characteristics; for example, household demographics and selfreported pesticide use information, considering information available with and without a home visit. Focusing on five organophosphate and pyrethroid pesticides, we used classification and regression tree analysis (CART) to disaggregate the pesticide concentration data into homogenous subsamples according to housing characteristics, which allowed us to identify households and associated networks impacted by the mismanagement of pesticides. The CART analysis demonstrated reasonable sensitivity and specificity given more extensive household information but generally poor performance using only information available without a home visit. Apartments with high concentrations of cyfluthrin, a pyrethroid of interest given that it is a restricted use pesticide, were more likely to be associated with Hispanic residents who resided in their current apartment for more than 5 yr, consistent with documented pesticide usage patterns. We conclude that using CART as an exploratory technique to better understand the home characteristics associated with elevated pesticide levels may be a viable approach for risk management in large multiunit housing developments.

Phosphorylation of hepatitis C virus RNA polymerases ser29 and ser42 by protein kinase C-related kinase 2 regulates viral RNA replication

Journal of virology, 2014

Hepatitis C virus (HCV) nonstructural protein 5B (NS5B), an RNA-dependent RNA polymerase (RdRp), ... more Hepatitis C virus (HCV) nonstructural protein 5B (NS5B), an RNA-dependent RNA polymerase (RdRp), is the key enzyme for HCV RNA replication. We previously showed that HCV RdRp is phosphorylated by protein kinase C-related kinase 2 (PRK2). In the present study, we used biochemical and reverse-genetics approaches to demonstrate that HCV NS5B phosphorylation is crucial for viral RNA replication in cell culture. Two-dimensional phosphoamino acid analysis revealed that PRK2 phosphorylates NS5B exclusively at its serine residues in vitro and in vivo. Using in vitro kinase assays and mass spectrometry, we identified two phosphorylation sites, Ser29 and Ser42, in the Δ1 finger loop region that interacts with the thumb subdomain of NS5B. Colony-forming assays using drug-selectable HCV subgenomic RNA replicons revealed that preventing phosphorylation by Ala substitution at either Ser29 or Ser42 impairs HCV RNA replication. Furthermore, reverse-genetics studies using HCV infectious clones encod...

Development of Bio-Machine Based on the Plant Response to External Stimuli

Journal of Robotics, 2011

In the area of biorobotics, intense research work is being done based on plant intelligence. Any ... more In the area of biorobotics, intense research work is being done based on plant intelligence. Any living cell continuously receives information from the environment. In this paper, research is conducted on the plant nameddescoingsiixhaworthioides(Pepe) obtaining the action potential signals and its responses to stimulations of different light modes. The plant electrical signal is the reaction of plant’s stimulation owing to various environmental conditions. Action potentials are responsible for signaling between plant cells and communication from the plants can be achieved through modulation of various parameters of the electrical signal in the plant tissue. The modulated signals are used for providing information to the microcontroller’s algorithm for working of the bio-machine. The changes of frequency of action potentials in plant are studied. Electromyography (EMG) electrodes and needle-type conductive electrodes along with electronic modules are used to collect and transform the...

OA06-02. Monospecific expansion of SIVmac251 during acute infection masks multiple transmitted virus variants revealed during the chronic phase

Retrovirology, 2009

Event shapes and azimuthal correlations in Z+jets events in pp collisions at s=7 TeV

Physics Letters B, 2013

Measurements of event shapes and azimuthal correlations are presented for events where a Z boson ... more Measurements of event shapes and azimuthal correlations are presented for events where a Z boson is produced in association with jets in proton-proton collisions. The data collected with the CMS detector at the CERN LHC at √ s = 7 TeV correspond to an integrated luminosity of 5.0 fb −1. The analysis provides a test of predictions from perturbative QCD for a process that represents a substantial background to many physics channels. Results are presented as a function of jet multiplicity, for inclusive Z boson production and for Z bosons with transverse momenta greater than 150 GeV, and compared to predictions from Monte Carlo event generators that include leadingorder multiparton matrix-element (with up to four hard partons in the final state) and next-to-leading-order simulations of Z + 1-jet events. The experimental results are corrected for detector effects, and can be compared directly with other QCD models.

Supersolid Helium at High Pressure

Physical Review Letters, 2006

We have measured the pressure dependence of the supersolid fraction by a torsional oscillator tec... more We have measured the pressure dependence of the supersolid fraction by a torsional oscillator technique. Superflow is found from 25.6 bar up to 136.9 bar. The supersolid fraction in the low temperature limit increases from 0.6 % at 25.6 bar near the melting boundary up to a maximum of 1.5% near 55 bar before showing a monotonic decrease with pressure extrapolating to zero near 170 bar.

Photon-hadron jet correlations inp+pandAu+Aucollisions atsNN=200GeV

Physical Review C, 2009

Cleaved high-molecular-weight kininogen and its domain 5 inhibit migration and invasion of human prostate cancer cells through the epidermal growth factor receptor pathway

Oncogene, 2009

Upregulation and activation of epidermal growth factor receptor and/or urokinase-type plasminogen... more Upregulation and activation of epidermal growth factor receptor and/or urokinase-type plasminogen activator receptor in a variety of cancers have been shown to be associated with poor prognosis. High-molecular-weight kininogen can be hydrolysed by plasma kallikrein to bradykinin and cleaved high-molecular-weight kininogen (HKa). HKa and its domain 5 (D5) both have been shown to have potent anti-angiogenic activity. We now show that HKa blocks human prostate cancer cell (DU145) migration by 76.0 ± 2.4% at 300 nM and invasion by 78.0±12.9% at 11.1 nM. D5 inhibits tumor migration and invasion in a concentration-dependent manner. Stimulation by basic fibroblast growth factor (bFGF) or vascular endothelial growth factor results in clustering of urokinase-type plasminogen activator receptor (uPAR) and epidermal growth factor receptor (EGFR) on the surface of DU145 cells. The co-localization of uPAR and EGFR is prevented by HKa. Immunoprecipitation suggests that uPAR, EGFR and a5b1 integrin formed a ternary complex. Immunoblotting shows that HKa significantly decreases the bFGF-transactivated phosphorylation of EGFR at Tyr 1173 between 30 min and 4 h. The phosphorylation of extracellular signal-regulated kinase (ERK) and AKT, which are downstream effectors of EGFR, is also inhibited by HKa. These novel data indicate that HKa and D5 inhibit migration and invasion of human prostate cancer cells through an EGFR/uPAR pathway, suggesting the therapeutic potential of HKa and D5 to decrease metastasis of human prostate cancer.