Biomedical subjects
Publications and source records attributed to D Kim.
Using data collected at the psi(3770) resonance with the CLEO-c detector at the Cornell e+e- storage ring, we present searches for 25 charmless decay modes of the psi(3770), mostly multibody final states. No evidence for charmless decays is found.
Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the Bs meson in e+e- annihilation at the Y(5S) resonance. We find 14 candidates consistent with Bs decays into final states with a J/psi or a Ds(*)- . The probability that we have observed a background fluctuation is less than 8 x 10(-10) . We have established that at the energy of the Y(5S) resonance Bs production proceeds predominantly through the creation of Bs*Bs* pairs. We find sigma(e+e- --> Bs*Bs*) = [0.11(-0.03))(+0.04)(stat) +/- 0.02(syst)]nb , and set the following limits: sigma(e+e- --> BsBs)/ sigma(e+ e- --> Bs*Bs*) <0.16 and [sigma(e+e- --> BsBs*) + sigma(e+e- --> Bs*Bs)]/sigma(e+e- -->Bs*Bs*) < 0.16 (90% C.L.). The mass of the Bs* meson is measured to be M(Bs*) = [5.414+/- 0.001(stat) +/- 0.003(syst)] GeV/c2 .
We find that the fractal scaling in a class of scale-free networks originates from the underlying tree structure called a skeleton, a special type of spanning tree based on the edge betweenness centrality. The fractal skeleton has the property of the critical branching tree. The original fractal networks are viewed as a fractal skeleton dressed with local shortcuts. An in silico model with both the fractal scaling and the scale-invariance properties is also constructed. The framework of fractal networks is useful in understanding the utility and the redundancy in networked systems.
Liver transplantation (OLT) is often complicated by renal failure. Hepatitis C (HCV) is said to be a risk factor for renal failure after OLT, but few studies have analyzed this directly. We evaluated all patients who received a liver transplant from 1995 through 2003. There were 147 patients infected with HCV and 202 not infected. Patients with HCV were further divided into 114 patients with benign HCV and 33 patients with severe HCV defined by bridging fibrosis or cirrhosis. The groups were evaluated for the development of renal insufficiency defined as a creatinine above 1.8 mg/dL on three consecutive occasions or renal failure as defined by the need for dialysis or renal transplant. The incidence of renal failure in patients with HCV was 10.2% and in patients without HCV was 3.5% (P = .004). Patients with severe HCV had an incidence of 12.1% vs 9.7% for patients with mild HCV. The linear trend in renal failure from non-HCV to mild HCV to severe HCV was significant (P = .012). The incidence of renal insufficiency was 23.4% in patients with HCV and 14.9% in patients without HCV (P = .080). The incidence was 32.3% in patients with severe HCV and 20.6% in patients with mild HCV. The trend in renal insufficiency across the three groups was mildly significant (P = .042). On multivariate analysis, HCV was a risk factor for renal failure with a relative risk of 2.58 (P = .045). The study suggests that HCV and the severity of recurrent HCV are risk factors for renal dysfunction after liver transplantation.
BACKGROUND: Many endogenous and exogenous factors are known to cause enlarged pilosebaceous pores. Such factors include sex, genetic predisposition, ageing, chronic ultraviolet light exposure, comedogenic xenobiotics, acne and seborrhoea. This study was an attempt to determine the factors related to enlarged pores. OBJECTIVES: To assess the relationship of sebum output, age, sex, hormonal factors and severity of acne with pore size. METHODS: A prospective, randomized, controlled study was designed. A total of 60 volunteers, 30 males and 30 females, were recruited for this study. Magnified images of pores were taken using a dermoscopic video camera and measured using an image analysis program. The sebum output level was measured with a Sebumeter. RESULTS: Using multiple linear regression analysis, increased pore size was significantly associated with increased sebum output level, sex and age. Among the variables, sebum output level correlated most with the pore size followed by male sex. In comparing male and female participants, males had higher correlation between the sebum output level and the pore size (male: r = 0.47, female: r = 0.38). Thus, additional factors seem to influence pore size in females. Pore size was significantly increased during the ovulation phase (P = 0.008), but severity of acne was not significantly associated with the pore size. CONCLUSIONS: Enlarged pore sizes are associated with increased sebum output level, age and male sex. In female patients, additional hormonal factors, such as those of the menstrual cycle, affect the pore size.
STUDY OBJECTIVE: Few studies have distinguished between the effects of different forms of social capital on health. This study distinguished between the health effects of summary measures tapping into the constructs of community bonding and community bridging social capital. DESIGN: A multilevel logistic regression analysis of community bonding and community bridging social capital in relation to individual self rated fair/poor health. SETTING: 40 US communities. PARTICIPANTS: Within community samples of adults (n = 24 835), surveyed by telephone in 2000-2001. MAIN RESULTS: Adjusting for community sociodemographic and socioeconomic composition and community level income and age, the odds ratio of reporting fair or poor health was lower for each 1-standard deviation (SD) higher community bonding social capital (OR = 0.86; 95% = 0.80 to 0.92) and each 1-SD higher community bridging social capital (OR = 0.95; 95% CI = 0.88 to 1.02). The addition of indicators for individual level bonding and bridging social capital and social trust slightly attenuated the associations for community bonding social capital (OR = 0.90, 95% CI = 0.84 to 0.97) and community bridging social capital (OR = 0.96, 95% CI = 0.89 to 1.03). Individual level high formal bonding social capital, trust in members of one's race/ethnicity, and generalised social trust were each significantly and inversely related to fair/poor health. Furthermore, significant cross level interactions of community social capital with individual race/ethnicity were seen, including weaker inverse associations between community bonding social capital and fair/poor health among black persons compared with white persons. CONCLUSIONS: These results suggest modest protective effects of community bonding and community bridging social capital on health. Interventions and policies that leverage community bonding and bridging social capital might serve as means of population health improvement.
BACKGROUND: Function of the retinoblastoma tumor suppressor protein (pRB) may be compromised at a genetic level by gene loss or mutation or at a post-translational level by hyperphosphorylation. In this study, we examined adult soft tissue sarcomas (ASTS) to determine if alterations of pRB were associated with distinct patterns of pRB expression and clinical outcome. DESIGN: We investigated 86 ASTS patients using monoclonal antibodies that distinguish between hyperphosphorylated and underphosphorylated pRB products. We also used microsatellite analysis to investigate the genetic status of the RB locus. We correlated pRB alterations with proliferative activity, and with clinicopathological outcomes. RESULTS: Altered patterns of pRB expression are common in ASTS occurring in 84% of cases, and it is significantly associated with proliferative activity (p<0.001). Patients whose tumors either lack expression of pRB, or express hyperphosphorylated forms of pRB, have poor survivals compared to patients whose tumors exhibit a normal, underphosphorylated pattern of pRB expression (p=0.03). In addition, 63% of cases lacking expression of pRB showed loss-of-heterozygosity at the locus. CONCLUSIONS: Inactivation of pRB is common in adult STS, which may be due to either gene loss or post-translational modification, namely hyper-phosphorylation. Both mechanisms are associated with tumor cell proliferation and poor survival.
OBJECTIVE: To evaluate the independent effect of premorbid antiplatelet use on incident ischemic stroke severity and outcome at discharge. METHODS: The authors studied consecutive patients presenting within 24 hours of ischemic stroke over a 1-year period. National Institutes of Health Stroke Scale (NIHSS) score at presentation was used as index of stroke severity and a modified Rankin scale of 0 to 1 at discharge as index of good functional outcome. Patients were categorized according to their premorbid antiplatelet use as antiplatelet-inclusive (AI) and no antiplatelet (NA). Demographic data, risk factors, pertinent laboratory tests, other medications, and stroke mechanisms were controlled for across the two groups using multivariate logistic regression. RESULTS: A total of 260 individuals met study criteria: 92 patients were on antiplatelet agents prior to admission, 168 were on no antiplatelets. Pretreatment with antiplatelet was associated with lower presenting median NIHSS (4.5 vs 7, p = 0.005). Antiplatelet use was associated with less severe stroke at presentation in those having no history of stroke or TIA (4.8 vs 8.0, p = 0.03) but not in those with a prior history of stroke or TIA (4.9 vs 4.9, p = 0.987). The likelihood of a good outcome was increased in those on antiplatelets after adjusting for other variables (OR 2.105, p = 0.0073). CONCLUSIONS: Prestroke use of antiplatelet may be associated with reduced severity of incident ischemic strokes in those with no prior history of stroke or TIA, and with an increased likelihood of a good discharge outcome regardless of prior cerebrovascular event history.
We use data collected by the CLEO III detector at the Cornell Electron Storage Ring to measure the inclusive yields of D(s) mesons as B(Y(5S) --> D(s)X) = (44-7 +/- 4.2 +/- 9.9)% and B(Y(4S) --> D(s)X) = (18.1 +/- 0.5 +/- 2.8)%. From these measurements, we make a model dependent estimate of the ratio of B(s)*B(s)* to the total bb quark pair production of (16.0 +/- 2.6 +/- 5.8)% at the Y(5S) energy.
We extract a relatively precise value for the decay constant of the meson by measuring B(D+ --> mu+nu) = (4.40 +/-0.66(+0.09)(-0.12) x 10(-4) using 281 pb(-1) of data taken on phi(3770) the resonance with the CLEO-c detector. We find fD+ = (222.6 +/- 16.7(+2.8)(-3.4)) MeV, and compare with current theoretical calculations. We also set a 90% confidence upper limit on B(D+e+nu)< 2.4 x 10(-5) which constrains new physics models.
Using 0.8 x 10(6) D+ D- pairs collected with the CLEO-c detector at the psi(3770) resonance, we have searched for flavor-changing neutral current and lepton-number-violating decays of D+ mesons to final states with dielectrons. We find no indication of either, obtaining 90% confidence level upper limits of B(D+ --> pi+ e+ e-) < 7.4 x 10(-6), B(D+ --> pi- e+ d+) < 3.6 x 10(-6), B(D+ --> K+ e+ e-) < 6.2 x 10(-6), and B(D+ --> K- e+ e+) < 4.5 x 10(-6).
Adolescence is a period of progressive changes in brain that likely contribute to the maturation of behavior. Human adolescents consume large amounts of ethanol. To investigate the effects of ethanol on adolescent neural progenitor cells, male rats (35-40 days old) were treated with an acute dose of ethanol (1.0, 2.5 or 5.0 g/kg, i.g.) or vehicle that resulted in peak blood levels of 33, 72, and 131 mg/dl, respectively. Bromodeoxyuridine (300 mg/kg i.p.) was administered to label dividing cells and rats were killed at 5 h to assess proliferation or at 28 days to assess cell survival and differentiation. After 5 h, bromodeoxyuridine-immunoreactivity was reduced by 63, 97 and 99% in the rostral migratory stream and 34, 71 and 99% in the subventricular zone by 1.0, 2.5 and 5.0 g/kg of ethanol respectively. In the dentate gyrus, ethanol reduced bromodeoxyuridine-immunoreactivity by 29, 40, and 78% at the three doses respectively. The density of doublecortin immunoreactivity was decreased after 3 days and the number of bromodeoxyuridine+ cells remained decreased at 28 days when most hippocampal bromodeoxyuridine+ cells coexpressed neuronal nuclei, a neuronal marker. These studies indicate that the adolescent brain is very sensitive to acute ethanol inhibition of neurogenesis.
With the first data sample collected by the CLEO-c detector at the psi(3770) resonance we have studied four exclusive semileptonic decays of the D0 meson. Our results include the first observation and absolute branching fraction measurement for D0 --> p-e+ve and improved measurements of the absolute branching fractions for D0 decays to K-e+ve, pi-e+ve, and K*-e+ve.
Using 55.8 pb(-1) of e+e- collisions recorded at the psi(3770) resonance with the CLEO-c detector at CESR, we determine absolute hadronic branching fractions of charged and neutral D mesons using a double tag technique. Among measurements for three D0 and six D+ modes, we obtain reference branching fractions B(D0-->K-pi+)=(3.91+/-0.08+/-0.09)% and B(D+-->K-pi+pi+)=(9.5+/-0.2+/-0.3)%, where the uncertainties are statistical and systematic, respectively. Final state radiation is included in these branching fractions by allowing for additional, unobserved, photons in the final state. Using a determination of the integrated luminosity, we also extract the cross sections sigma(e+e- -->D0D0)=(3.60+/-0.07(+0.07)(-0.05)) nb and sigma(e+e- -->D+D-)=(2.79+/-0.07(+0.10)(-0.04)) nb.
The h(c)((1)P(1)) state of charmonium has been observed in the reaction psi(2S) --> pi(0)h(c) --> (gammagamma)(gammaeta(c)) using 3.08 x10(6) psi(2S) decays recorded in the CLEO detector. Data have been analyzed both for the inclusive reaction, where the decay products of the eta(c) are not identified, and for exclusive reactions, in which eta(c) decays are reconstructed in seven hadronic decay channels. We find M(h(c)) = 3524.4 +/- 0.6 +/- 0.4 MeV which corresponds to a hyperfine splitting DeltaM(hf)(1P) triple-bond pi(0)h(c)) x B(h(c) --> gammaeta(c)) = (4.0 +/- 0.8 +/- 0.7) x 10(-4).
Using data accumulated with the CLEO detector corresponding to an integrated luminosity of [symbol: see text] = 5.63 pb(-1) on the peak of the psi(2S) [3.08 x 10(6) psi(2S) decays] and 20.70 pb(-1) at square root of[s] = 3.67 GeV, we report first measurements of the branching fractions for the following 13 decay modes of the psi(2S): eta3pi, &eta'3pi, rhoK+K-, K+K-pi+pi-pi0, 2(K+K-), 2(K+K-)pi0, rhopp, pppi+pi-pi0, etapp, ppK+K-, lambdalambdapi+pi-, lambdapK+, and lambdapK+pi+pi-, and more precise measurements of 8 previously measured modes: 2(pi+pi-), rhopi+pi-, 2(pi+pi-)pi0, omegapi+pi-, K+K-pi+pi-, omegaK+K-, phiK+K-, and pppi+pi-. We also report new branching fraction measurements of phipi+pi- and omegapp and upper limits for etapi+pi-, etaK+K-, and phivpp. Results are compared, where possible, with the corresponding J/psi branching ratios to provide new tests of the 12% rule.
We introduce the notion of globally updating evolution for a class of weighted networks, in which the weight of a link is characterized by the amount of data packet transport flowing through it. By noting that the packet transport over the network is determined nonlocally, this approach can explain the generic nonlinear scaling between the strength and the degree of a node. We demonstrate by a simple model that the strength-driven evolution scheme recently introduced can be generalized to a nonlinear preferential attachment rule, generating the power-law behaviors in degree and in strength simultaneously.
We study the load distribution in weighted networks by measuring the effective number of optimal paths passing through a given vertex. The optimal path, along which the total cost is minimum, crucially depends on the cost distribution function p(c) (c) . In the strong disorder limit, where p(c) (c) approximately c(-1) , the load distribution follows a power law both in the Erdös-Rényi (ER) random graphs and in the scale-free (SF) networks, and its characteristics are determined by the structure of the minimum spanning tree. The distribution of loads at vertices with a given vertex degree also follows the SF nature similar to the whole load distribution, implying that the global transport property is not correlated to the local structural information. Finally, we measure the effect of disorder by the correlation coefficient between vertex degree and load, finding that it is larger for ER networks than for SF networks.