623 research outputs found
An interferometric complementarity experiment in a bulk Nuclear Magnetic Resonance ensemble
We have experimentally demonstrated the interferometric complementarity,
which relates the distinguishability quantifying the amount of which-way
(WW) information to the fringe visibility characterizing the wave feature
of a quantum entity, in a bulk ensemble by Nuclear Magnetic Resonance (NMR)
techniques. We primarily concern on the intermediate cases: partial fringe
visibility and incomplete WW information. We propose a quantitative measure of
by an alternative geometric strategy and investigate the relation between
and entanglement. By measuring and independently, it turns out that
the duality relation holds for pure quantum states of the
markers.Comment: 13 page, 5 PS figure
How early can myocardial iron overload occur in Beta thalassemia major?
BACKGROUND: Myocardial siderosis is the most common cause of death in patients with beta thalassemia major(TM). This study aimed at investigating the occurrence, prevalence and severity of cardiac iron overload in a young Chinese population with beta TM.
METHODS AND RESULTS: We analyzed T2* cardiac magnetic resonance (CMR), left ventricular ejection fraction (LVEF) and serum ferritin (SF) in 201 beta TM patients. The median age was 9 years old. Patients received an average of 13 units of blood per year. The median SF level was 4536 ng/ml and 165 patients (82.1%) had SF>2500 ng/ml. Myocardial iron overload was detected in 68 patients (33.8%) and severe myocardial iron overload was detected in 26 patients (12.6%). Twenty-two patients â€10 years old had myocardial iron overload, three of whom were only 6 years old. No myocardial iron overload was detected under the age of 6 years. Median LVEF was 64% (measured by CMR in 175 patients). Five of 6 patients with a LVEF<56% and 8 of 10 patients with cardiac disease had myocardial iron overload.
CONCLUSIONS: The TM patients under follow-up at this regional centre in China patients are younger than other reported cohorts, more poorly-chelated, and have a high burden of iron overload. Myocardial siderosis occurred in patients younger than previously reported, and was strongly associated with impaired LVEF and cardiac disease. For such poorly-chelated TM patients, our data shows that the first assessment of cardiac T2* should be performed as early as 6 years old
Forecasting the Impacts of Silver and Bighead Carp on the Lake Erie Food Web
Nonindigenous bigheaded carps (Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix; hereafter, âAsian carpsâ [AC]) threaten to invade and disrupt food webs and fisheries in the Laurentian Great Lakes through their high consumption of plankton. To quantify the potential effects of AC on the food web in Lake Erie, we developed an Ecopath with Ecosim (EwE) food web model and simulated four AC diet composition scenarios (high, low, and no detritus and low detritus with Walleye Sander vitreus and Yellow Perch Perca flavescens larvae) and two nutrient load scenarios (the 1999 baseline load and 2Ă the baseline [HP]). We quantified the uncertainty of the potential AC effects by coupling the EwE model with estimates of parameter uncertainty in AC production, consumption, and predator diets obtained using structured expert judgment. Our model projected mean ± SD AC equilibrium biomass ranging from 52 ± 34 to 104 ± 75 kg/ha under the different scenarios. Relative to baseline simulations without AC, AC invasion under all detrital diet scenarios decreased the biomass of most fish and zooplankton groups. The effects of AC in the HP scenario were similar to those in the detrital diet scenarios except that the biomasses of most Walleye and Yellow Perch groups were greater under HP because these fishes were buffered from competition with AC by increased productivity at lower trophic levels. Asian carp predation on Walleye and Yellow Perch larvae caused biomass declines among all Walleye and Yellow Perch groups. Large food web impacts of AC occurred in only 2% of the simulations, where AC biomass exceeded 200 kg/ha, resulting in biomass declines of zooplankton and planktivorous fish near the levels observed in the Illinois River. Our findings suggest that AC would affect Lake Erie's food web by competing with other planktivorous fishes and by providing additional prey for piscivores. Our methods provide a novel approach for including uncertainty into forecasts of invasive species' impacts on aquatic food webs. Received December 6, 2014; accepted July 15, 201
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Neuropsychological Changes in a Prospectively Followed Cohort of Intravenous Drug Users with and without HIV
We followed a cohort of 223 intravenous drug users (99 HIV and 124 HIV+) for up to 3.5 years, examining change in performance over time as a function of HIV status, disease severity, and neurological signs and symptoms. Analyses were performed by applying generalized estimating equations (GEE) to regression analyses with repeated measures, and controlled for age, education, and length of substance use. None of the subjects had AIDS at baseline. There were 147 men (85 HIV+ and 62 HIV) and 76 women (39 HIV+ and 37 HIV). Memory performance was worse in the HIV+ than HIVâ women. In the men, performance on the memory, executive, language, and attention factors improved significantly overtime, but this improvement was attenuated in the HIV men for the attention and orientation factors. In the HIV+ women. AIDS was associated with worsening performance on attention tests. The presence or onset of clinically significant neurological findings was associated with poorer language and motor speed performance. In the HIV+ men, memory performance was worse when the CD4 count fell below 200: it declined over time in men with AIDS but not in those without. A learning effect for language was attenuated in men who developed AIDS. The presence or development of a clinically significant neurological sign was associated with poorer memory, executive, language, attention, and motor speed performance. Our findings parallel those that we previously reported in a prospectively followed cohort of gay men. In combination, our studies of gay men and IDU cohorts suggest that (a) HIV can affect cognition early, even when the patient is medically asymptomatic; (b) cognitive difficulties worsen as the severity of HIV infection increases; and (c) the advent of clinically significant neurologic signs is associated with progression to more severe cognitive deficits. Our data suggest that the neurological and neuropsychological changes are both manifestations of the central effect of HIV on the CNS
Label-Free Fluorescent Poly(amidoamine) Dendrimer for Traceable and Controlled Drug Delivery
Poly(amidoamine) dendrimer (PAMAM) is well-known for its high efficiency as a drug delivery vehicle. However, the intrinsic cytotoxicity and lack of a detectable signal to facilitate tracking have impeded its practical applications. Herein, we have developed a novel label-free fluorescent and biocompatible PAMAM derivative by simple surface modification of PAMAM using acetaldehyde. The modified PAMAM possessed a strong green fluorescence, which was generated by the C=N bonds of the resulting Schiff Bases via n-?â transition, while the intrinsic cytotoxicity of PAMAM was simultaneously ameliorated. Through further PEGylation, the fluorescent PAMAM demonstrated excellent intracellular tracking in human melanoma SKMEL28 cells. In addition, our PEGylated fluorescent PAMAM derivative achieved enhanced loading and delivery efficiency of the anticancer drug doxorubicin (DOX) compared to the original PAMAM. Importantly, the accelerated kinetics of DOX-encapsulated fluorescent PAMAM nanocomposites in an acidic environment facilitated intracellular drug release, which demonstrated comparable cytotoxicity to that of the free-form doxorubicin hydrochloride (DOX·HCl) against melanoma cells. Overall, our label free fluorescent PAMAM derivative offers a new opportunity of traceable and controlled delivery for DOX and other drugs of potential clinical importance
Experimental Implementation of Hogg's Algorithm on a Three-Quantum-bit NMR Quantum Computer
Using nuclear magnetic resonance (NMR) techniques with three-qubit sample, we
have experimentally implemented the highly structured algorithm for the 1-SAT
problem proposed by Hogg. A simplified temporal averaging procedure was
employed to the three-qubit spin pseudo-pure state. The algorithm was completed
with only a single evaluation of structure of the problem and the solutions
were found with probability 100%, which outperform both unstructured quantum
and the best classical search algorithm.Comment: Revtex, 14 pages and 1 table, 4 EPS figure
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Risk of Human Immunodeficiency Virus Type 1-Related Neurologic Disease in a Cohort of Intravenous Drug Users
Background: Although the proportion of cases of acquired immunodeficiency syndrome related to intravenous drug use has increased dramatically over the past decade, there has been no longitudinal examination of primary neurologic disease in this group. Objective: To study the development of neurologic disease in human immunodeficiency virus (HIV)ânegative and HIV-positive men and women who were intravenous drug users over a 3.5-year period. Design: Prospective observational cohort study. Setting: Subjects were recruited from an infectious disease clinic at a New York City Hospital or from a methadone maintenance program. Participants: Ninety-nine HIV-negative (62 men and 37 women) and 124 HIV-positive (85 men and 39 women) intravenous drug users volunteered. Main Outcome Measure: The development of clinically significant manifestations in six neurologic domains. Results: With multivariate adjustment for current and past substance abuse, age, education, and head injury, we examined the odds of developing HIV-related neurologic disease. Extrapyramidal signs and reduced motor ability became increasingly apparent over time in HIV-infected men as their CD4 cell count declined and as the subjects developed the acquired immunodeficiency syndrome. Fewer neurologic signs were seen in the women. Conclusions: The impact of HIV infection among intravenous drug users parallels that in homosexual men and is independent of alcohol and other drug use
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Chronic Arsenic Exposure and Blood Glutathione and Glutathione Disulfide Concentrations in Bangladeshi Adults
Background: In vitro and rodent studies have shown that arsenic (As) exposure can deplete glutathione (GSH) and induce oxidative stress. GSH is the primary intracellular antioxidant; it donates an electron to reactive oxygen species, thus producing glutathione disulfide (GSSG). Cysteine (Cys) and cystine (CySS) are the predominant thiol/disulfide redox couple found in human plasma. Arsenic, GSH, and Cys are linked in several ways: a) GSH is synthesized via the transsulfuration pathway, and Cys is the rate-limiting substrate; b) intermediates of the methionine cycle regulate both the transsulfuration pathway and As methylation; c) GSH serves as the electron donor for reduction of arsenate to arsenite; and d) As has a high affinity for sulfhydryl groups and therefore binds to GSH and Cys. Objectives: We tested the hypothesis that As exposure is associated with decreases in GSH and Cys and increases in GSSG and CySS (i.e., a more oxidized environment). Methods: For this cross-sectional study, the Folate and Oxidative Stress Study, we recruited a total of 378 participants from each of five water As concentration categories: & 10 (n = 76), 10â100 (n = 104), 101â200 (n = 86), 201â300 (n = 67), and < 300 ”g/L (n = 45). Concentrations of GSH, GSSG, Cys, and CySS were measured using HPLC. Results: An interquartile range (IQR) increase in water As was negatively associated with blood GSH (mean change, â25.4 ”mol/L; 95% CI: â45.3, â5.31) and plasma CySS (mean change, â3.00 ”mol/L; 95% CI: â4.61, â1.40). We observed similar associations with urine and blood As. There were no significant associations between As exposure and blood GSSG or plasma Cys. Conclusions: The observed associations are consistent with the hypothesis that As may influence concentrations of GSH and other nonprotein sulfhydryls through binding and irreversible loss in bile and/or possibly in urine
Options for China in a Dollar Standard World: A Sovereign Currency Approach
This paper examines the fiscal and monetary policy options available to China as a sovereign currency-issuing nation operating in a dollar standard world. We first summarize a number of issues facing China, including the possibility of slower growth, global imbalances, and a number of domestic imbalances. We then analyze current monetary and fiscal policy formation and examine some policy recommendations that have been advanced to deal with current areas of concern. We next outline the sovereign currency approach and use it to analyze those concerns. We conclude with policy recommendations consistent with the policy space open to China
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