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Search Results: 1 - 10 of 34448 matches for " Jialun Zhou "
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Short-term risk of anaemia following initiation of combination antiretroviral treatment in HIV-infected patients in countries in sub-Saharan Africa, Asia-Pacific, and central and South America
Zhou Jialun,Jaquet Antoine,Bissagnene Emmanuel,Musick Beverly
Journal of the International AIDS Society , 2012, DOI: 10.1186/1758-2652-15-5
Abstract: Background The objective was to examine the short-term risk and predictors of anaemia following initiation of combination antiretroviral therapy (cART) in HIV-infected patients from the Western Africa, Eastern Africa, Southern Africa, Central Africa, Asian-Pacific, and Caribbean and Central and South America regions of the International Epidemiologic Databases to Evaluate AIDS (IeDEA) collaboration. Methods Anaemia was defined as haemoglobin of < 10 g/dL. Patients were included if they started cART with three or more drugs, had prior haemoglobin of > = 10 g/dL, and had one or more follow-up haemoglobin tests. Factors associated with anaemia up to 12 months were examined using Cox proportional hazards models and stratified by IeDEA region. Results Between 1998 and 2008, 19,947 patients initiated cART with baseline and follow-up haemoglobin tests (7358, 7289, 2853, 471, 1550 and 426 in the Western Africa, Eastern Africa, Southern Africa, Central Africa, Asian-Pacific, and Caribbean and Central and South America regions, respectively). At initiation, anaemia was found in 45% of Western Africa patients, 29% of Eastern Africa patients, 21% of Southern Africa patients, 36% of Central Africa patients, 15% of patients in Asian-Pacific and 14% of patients in Caribbean and Central and South America. Among patients with haemoglobin of > = 10 g/dL at baseline (13,445), the risks of anaemia were 18.2, 6.6, 9.7, 22.9, 11.8 and 19.5 per 100 person-years in the Western Africa, Eastern Africa, Southern Africa, Central Africa, Asian, and Caribbean and Central and South America regions, respectively. Factors associated with anaemia were female sex, low baseline haemoglobin level, low baseline CD4 count, more advanced disease stage, and initial cART containing zidovudine. Conclusions In data from 34 cohorts of HIV-infected patients from sub-Saharan Africa, Central and South America, and Asia, the risk of anaemia within 12 months of initiating cART was moderate. Routine haemoglobin monitoring was recommended in patients at risk of developing anaemia following cART initiation.
Failure to prescribe pneumocystis prophylaxis is associated with increased mortality, even in the cART era: results from the Treat Asia HIV observational database
Lim Poh-Lian,Zhou Jialun,Ditangco Rossana A,Law Matthew G
Journal of the International AIDS Society , 2012, DOI: 10.1186/1758-2652-15-1
Abstract: Background Pneumocystis jiroveci pneumonia (PCP) prophylaxis is recommended for patients with CD4 counts of less than 200 cells/mm3. This study examines the proportion of patients in the TREAT Asia HIV Observational Database (TAHOD) receiving PCP prophylaxis, and its effect on PCP and mortality. Methods TAHOD patients with prospective follow up had data extracted for prophylaxis using co-trimoxazole, dapsone or pentamidine. The proportion of patients on prophylaxis was calculated for each calendar year since 2003 among patients with CD4 counts of less than 200 cells/mm3. The effect of prophylaxis on PCP and survival were assessed using random-effect Poisson regression models. Results There were a total of 4050 patients on prospective follow up, and 90% of them were receiving combination antiretroviral therapy. Of those with CD4 counts of less than 200 cells/mm3, 58% to 72% in any given year received PCP prophylaxis, predominantly co-trimoxazole. During follow up, 62 patients developed PCP (0.5 per 100 person-years) and 169 died from all causes (1.36/100 person-years). After stratifying by site and adjusting for age, CD4 count, CDC stage and antiretroviral treatment, those without prophylaxis had no higher risk of PCP, but had a significantly higher risk of death (incident rate ratio 10.8, p < 0.001). PCP prophylaxis had greatest absolute benefit in patients with CD4 counts of less than 50 cells/mm3, lowering mortality rates from 33.5 to 6.3 per 100 person-years. Conclusions Approximately two-thirds of TAHOD patients with CD4 counts of less than 200 cells/mm3 received PCP prophylaxis. Patients without prophylaxis had significantly higher mortality, even in the era of combination ART. Although PCP may be under-diagnosed, these data suggest that prophylaxis is associated with important survival benefits.
Impact of drug classes and treatment availability on the rate of antiretroviral treatment change in the TREAT Asia HIV Observational Database (TAHOD)
Preeyaporn Srasuebkul, Alexandra Calmy, Jialun Zhou, Nagalingeswaran Kumarasamy, Matthew Law, Poh Lim, The TREAT Asia HIV Observational Database
AIDS Research and Therapy , 2007, DOI: 10.1186/1742-6405-4-18
Abstract: Rates of ART changes were examined in patients who started first line triple or more ART combination in TAHOD, and had at least one follow-up visit. Rates of ART changes were summarised per follow-up year, and factors associated with changes assessed using random-effect Poisson regression. The Kaplan-Meier method was used to determine durations of patients in their first, second and third regimen.A total of 1846 patients initiated an ART combination with at least three drugs. Median follow up time for the first treatment was 3.2 years. The overall rate of ART change was 29 per 100-person-year.In univariate analyses, rate of treatment change was significantly associated with exposure category, the country income category, the drug class combination, calendar year and the number of combinations. In multivariate analysis, compared to d4T/3TC/NVP, starting ART with another NNRTI-containing regimen, with PI only or with a triple NRTI regimen was associated with a higher risk of combination change (relative risk (RR) 1.6 (95% CI 1.64 – 1.96), p < 0.001, RR 3.39 (2.76 – 4.16) p < 0.001, RR 6.37 (4.51 – 9.00), p < 0.001). Being on a second or a third combination regimen was also associated with a decreased rate of ART change, compared with first ART combination (RR 0.82 (0.68 – 0.99), p = 0.035, RR 0.77 (0.61 – 0.97), p = 0.024). Sites with fewer than 12 drugs used had an increased rate of treatment changes (1.31 (1.13 – 1.51), p < 0.001). Injecting drug users, and other/unknown exposure was found to increase rate of treatment change (1.24 (1.00 – 1.54), p = 0.055). Percentages of patients who stopped treatment due to adverse events were 31, 27 and 32 in 1st, 2nd and 3rd treatment combinations, respectively.Our study suggests that drug availability impacts on ART prescription patterns. Our data, reflecting real clinic use in Asia, suggest that around half of all patients require second combination ART by 3 years after treatment initiation.In South and South-East Asia the nu
The structure of pentaquarks $P_c^+$ in the chiral quark model
Gang Yang,Jialun Ping
Physics , 2015,
Abstract: The recent experimental results of LHCb collaboration suggested the existence of pentaquark states with charmonium. To understand the structure of the states, a dynamical calculation of 5-quark systems with quantum numbers $IJ^P=\frac{1}{2}(\frac{1}{2})^\pm$, $\frac{1}{2}(\frac{3}{2})^\pm$ and $\frac{1}{2}(\frac{5}{2})^\pm$ is performed in the framework of chiral quark model with the help of gaussian expansion method. The results show that the negative parity states can be bound states while all of the positive parity states are the scattering states. The $P_c(4380)$ state is suggested to be the bound state of $\Sigma^*_cD$. Although the energy of $\Sigma_cD^*$ is very close to the mass of $P_c(4450)$, the inconsistent parity prevents the assignment. The calculated distances between quarks confirm the molecular nature of the states. Other five-quark bound states of the combination of $\Sigma_cD$ and $\Sigma^*_cD^*$ are also found in the region about 4.3GeV and 4.5GeV.
Study on $N\bar{N}$ $S$-wave Elastic Cross Section and Possible Bound States Within a Constituent Quark Model
Hourong Pang,Jialun Ping,Fan Wang
Physics , 2007, DOI: 10.1088/0256-307X/25/9/027
Abstract: In the framework of a chiral constituent quark model, considering the contributions of $\pi$ annihilation and one-gluon annihilation, the proton-antiproton $S$-wave elastic scattering cross section experimental data can be reproduced by adjusting properly one-gluon annihilation coupling constant. Meanwhile, using the fixed model parameter, we do a dynamical calculation for all possible $S$-wave nucleon-antinucleon states, the results show that, there is no $S$-wave bound state as indicated by a strong enhancement at threshold of $p\bar{p}$ in $J/\psi$ and $B$ decays.
The d' dibaryon in the quark-delocalization, color-screening model
Jialun Ping,Fan Wang,T. Goldman
Physics , 2000, DOI: 10.1103/PhysRevC.62.054007
Abstract: We study the questions of the existence and mass of the proposed $d' (IJ^P=00^-)$ dibaryon in the quark-delocalization, color-screening model (QDCSM). The transformation between physical and symmetry bases has been extended to the cases beyond the SU(2) orbital symmetry. Using parameters fixed by baryon properties and $NN$ scattering, we find a mild attraction in the $IJ^P=00^-$ channel, but it is not strong enough to form a deeply bound state as proposed for the $d'$ state. Nor does the (isospin) I=2 N$\Delta$ configuration have a deeply bound state. These results show that if a narrow dibaryon $d'$ state does exist, it must have a more complicated structure.
Dynamical calculation of $d^*$ mass and NN decay width in the quark delocalization, color screening model
Jialun Ping,Fan Wang,T. Goldman
Physics , 2000, DOI: 10.1016/S0375-9474(00)00593-5
Abstract: The mass estimate of the $d^* (IJ^P=03^+)$ dibaryon is improved by a dynamical calculation in the quark delocalization, color screening model. The partial decay width of $d^*$ into an $NN$ D-wave state is also obtained. The mass obtained is slightly larger than that obtained in adiabatic calculations, due to the anharmonicity of the effective potential between two $\Delta$'s. The value of the width obtained due to tensor one-gluon-exchange is about 5 MeV, comparable in magnitude to earlier results found using pion exchange.
The effect of hidden color channels on Nucleon-Nucleon interaction
Fan Wang,Jialun Ping,Hongxia Huang
Physics , 2009,
Abstract: This letter reports the nucleon-nucleon($NN$) interaction obtained from multi-channel, including hidden color channels, coupling quark model calculation. The results show that the hidden color channels coupling provides the intermediate range attraction which is usually assumed to be due to multi-$\pi$ or $\sigma$ meson exchange and that the short and intermediate range $NN$ interaction can be described solely by the fundamental quark-gluon degree of freedom of QCD.
Possible $H$-like dibaryon states with heavy quarks
Hongxia Huang,Jialun Ping,Fan Wang
Physics , 2013, DOI: 10.1103/PhysRevC.89.035201
Abstract: Possible $H$-like dibaryon states $\Lambda_{c}\Lambda_{c}$ and $\Lambda_{b}\Lambda_{b}$ are investigated within the framework of quark delocalization color screening model. The results show that the interaction between two $\Lambda_{c}$'s is repulsive, so it cannot be bound state by itself. However, the strong attraction in $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ channels and the strong channel coupling, due to the central interaction of one-gluon-exchange and one-pion-exchange, among $\Lambda_{c}\Lambda_{c}$, $\Sigma_{c}\Sigma_{c}$ and $\Sigma^{*}_{c}\Sigma^{*}_{c}$ push the energy of system below the threshold of $\Lambda_{c}\Lambda_{c}$ by $22$ MeV. The corresponding system $\Lambda_{b}\Lambda_{b}$ has the similar properties as that of $\Lambda_{c}\Lambda_{c}$ system, and a bound state is also possible in $\Lambda_{b}\Lambda_{b}$ system.
The d* dibaryon in the extended quark-delocalization, color-screening model
Jialun Ping,Fan Wang,T. Goldman
Physics , 2000, DOI: 10.1103/PhysRevC.65.044003
Abstract: The quark-delocalization, color-screening model, extended by inclusion of a one-pion-exchange (OPE) tail, is applied to the study of the deuteron and the d* dibaryon. The results show that the properties of the deuteron (an extended object) are well reproduced, greatly improving the agreement with experimental data as compared to our previous study (without OPE). At the same time, the mass and decay width of the d* (a compact object) are, as expected, not altered significantly.
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