Unification of Radio Galaxies and Their Accretion/Jet Properties

We investigate the relation between black hole mass, M_bh, and jet power, Q_jet, for a sample of BL Lacs and radio quasars. We find that BL Lacs are separated from radio quasars by the FR I/II dividing line in M_bh-Q_jet plane, which strongly supports the unification scheme of FR I/BL Lac and FR II/radio quasar. The Eddington ratio distribution of BL Lacs and radio quasars exhibits a bimodal nature with a rough division at L_bol/L_Edd~0.01, which imply that they may have different accretion modes. We calculate the jet power extracted from advection dominated accretion flow (ADAF), and find that it require dimensionless angular momentum of black hole j~0.9-0.99 to reproduce the dividing line between FR I/II or BL Lac/radio quasar if dimensionless accretion rate mdot=0.01 is adopted, which is required by above bimodal distribution of Eddington ratios. Our results suggest that black holes in radio galaxies are rapidly spinning.Comment: To appear JAA in Jun

Temperature as a modifier of the effects of fine particulate matter on acute mortality in Hong Kong

Interactions between particulate matter with aerodynamic diameter less than or equal to 2.5 μm (PM2.5) and temperature on mortality have not been well studied, and results are difficult to synthesize. We aimed to assess modification of temperature on the association between PM2.5 and cause-specific mortality by stratifying temperature into low, medium, and high stratum in Hong Kong, using data from 1999 to 2011. The mortality effects of PM2.5 were stronger in low temperature stratum than those in high. The excess risk (%) per 10 μg/m3 increase in PM2.5 at lag 0–1 in low temperature stratum were 0.94% (95% confidence interval: 0.65, 1.24) for all natural, 0.88% (0.38, 1.37) for cardiovascular, and 1.15% (0.51, 1.79) for respiratory mortality. We found statistically significant interaction of PM2.5 and temperature between low and high temperature stratum for all natural mortality. Our results suggested that temperature might modify mortality effects of PM2.5 in Hong Kong.postprin

Interleukin-2 Confers Cardioprotection by Inhibiting Mitochondrial Permeability Transition Pore

In the present study, we determined whether interleukin-2 (IL-2) confers cardioprotection by inhibiting mitochondria permeability transition pore (MPTP) opening. In isolated rat hearts subject to 30 min ischemia and 120 min reperfusion (IR), IL-2 (50 U/ml) decreased the infarct size and LDH release, effects blocked by a selective kappa-opioid receptor antagonist, Nor-BNI (5 microM) or an opener of MPTP, atractyloside (Atr, 20 microM). In isolated ventricular myocytes subjected to anoxia and reoxygenation (AR), which reduced both the amplitude of the electrically induced [Ca2+]i transient and diastolic [Ca2+]i, IL-2 attenuated the AR-induced alterations and their effects were abolished by Atr. In addition, IL-2 attenuated the reduction in calcein fluorescence in myocytes subject to AR and reduced calcium-induced swelling in mitochondria of rat hearts subjected to IR, which were similar to effect of inhibitor of MPTP. The observations indicated that IL-2 confers cardioprotection by inhibiting the MPTP opening.published_or_final_versio

Hydrogen peroxide augments the injury effect of iron on the isolated rat heart and cardiomyocytes

2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Effect of iron loading on isolated rat myocardium

2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Luminescent platinum(II) complexes with functionalized N-heterocyclic carbene or diphosphine selectively probe mismatched and abasic DNA

published_or_final_versio

Influence of interleukin-2 on Ca2+ handling in rat ventricular myocytes

In the present study, we examined the effect of interleukin-2 (IL-2) on cardiomyocyte Ca2+ handling. The effects of steady-state and transient changes in stimulation frequency on the intracellular Ca2+ transient were investigated in isolated ventricular myocytes by spectrofluorometry. In the steady state (0.2 Hz) IL-2 (200 U/ml) decreased the amplitude of Ca2+ transients induced by electrical stimulation and caffeine. At 1.25 mM extracellular Ca2+ concentration ([Ca 2+]o), when the stimulation frequency increased from 0.2 to 1.0 Hz, diastolic Ca2+ level and peak intracellular Ca 2+ concentration ([Ca2+]i), as well as the amplitude of the transient, increased. The positive frequency relationships of the peak and amplitude of [Ca2+]i transients were blunted in the IL-2-treated myocytes. The effect of IL-2 on the electrically induced [Ca2+]i transient was not normalized by increasing [Ca2+]o to 2.5 mM. IL-2 inhibited the frequency relationship of caffeine-induced Ca2+ release. Blockade of sarcoplasmic reticulum (SR) Ca2+-ATPase with thapsigargin resulted in a significant reduction of the amplitude-frequency relationship of the transient similar to that induced by IL-2. The restitutions were not different between control and IL-2 groups at 1.25 mM [Ca2+]o, which was slowed in IL-2-treated myocytes when [Ca2+]o was increased to 2.5 mM. There was no difference in the recirculation fraction (RF) between control and IL-2-treated myocytes at both 1.25 and 2.5 mM [Ca 2+]o. The effects of IL-2 on frequency relationship, restitution, and RF may be due to depressed SR functions and an increased Na+-Ca2+ exchange activity, but not to any change in L-type Ca2+ channels. © 2003 Elsevier Ltd. All rights reserved.postprin

Impact of the 2009 H1N1 Pandemic on Age-Specific Epidemic Curves of Other Respiratory Viruses: A Comparison of Pre-Pandemic, Pandemic and Post-Pandemic Periods in a Subtropical City

published_or_final_versio

Age-specific epidemic waves of influenza and respiratory syncytial virus in a subtropical city

published_or_final_versio

A maize landrace that emits defense volatiles in response to herbivore eggs possesses a strongly inducible terpene synthase gene.

Maize (Zea mays) emits volatile terpenes in response to insect feeding and egg deposition to defend itself against harmful pests. However, maize cultivars differ strongly in their ability to produce the defense signal. To further understand the agroecological role and underlying genetic mechanisms for variation in terpene emission among maize cultivars, we studied the production of an important signaling component (E)-caryophyllene in a South American maize landrace Braz1006 possessing stemborer Chilo partellus egg inducible defense trait, in comparison with the European maize line Delprim and North American inbred line B73. The (E)-caryophyllene production level and transcript abundance of TPS23, terpene synthase responsible for (E)-caryophyllene formation, were compared between Braz1006, Delprim, and B73 after mimicked herbivory. Braz1006-TPS23 was heterologously expressed in E. coli, and amino acid sequences were determined. Furthermore, electrophysiological and behavioral responses of a key parasitic wasp Cotesia sesamiae to C. partellus egg-induced Braz1006 volatiles were determined using coupled gas chromatography electroantennography and olfactometer bioassay studies. After elicitor treatment, Braz1006 released eightfold higher (E)-caryophyllene than Delprim, whereas no (E)-caryophyllene was detected in B73. The superior (E)-caryophyllene production by Braz1006 was positively correlated with high transcript levels of TPS23 in the landrace compared to Delprim. TPS23 alleles from Braz1006 showed dissimilarities at different sequence positions with Delprim and B73 and encodes an active enzyme. Cotesia sesamiae was attracted to egg-induced volatiles from Braz1006 and synthetic (E)-caryophyllene. The variation in (E)-caryophyllene emission between Braz1006 and Delprim is positively correlated with induced levels of TPS23 transcripts. The enhanced TPS23 activity and corresponding (E)-caryophyllene production by the maize landrace could be attributed to the differences in amino acid sequence with the other maize lines. This study suggested that the same analogous genes could have contrasting expression patterns in different maize genetic backgrounds. The current findings provide valuable insight not only into genetic mechanisms underlying variation in defense signal production but also the prospect of introgressing the novel defense traits into elite maize varieties for effective and ecologically sound protection of crops against damaging insect pests