Biomedical subjects

Ye Luo

Publications and source records attributed to Ye Luo.

11 recordsLinked to original sources

PubMed2007

Sexual practices and sexual satisfaction: a population based study of Chinese urban adults.

This study examined sexual satisfaction and its social and behavioral correlates among urbanites aged 20-64 in China, using data from a nationally representative sample of 1,194 women and 1,217 men with a spouse or other long-term sexual partner with whom they had sex during the last year. The results from structural equation models suggest a multiplex set of determinants of sexual satisfaction, including relationship characteristics, sexual knowledge and personal values, physical vitality, and environmental impediments. A large proportion of the effect of these background characteristics was mediated by frequent orgasms, varied sexual practices, and perceived partner affection. In particular, much of the effect of knowledge and beliefs was mediated through variety in sexual practices. While many of the observed patterns were shared among women and men, much of the effect of relationship characteristics was mediated through perceived partner affection for women. Men, in contrast, paid greater attention to his partner's physical attractiveness and to her extramarital sex. A sexual transition is well underway in urban China, even if more rapidly for men than for women. While knowledge and values are arguably more important in this transitional period, many antecedents of sexual well-being drawn from the literature on sexual behavior in developed Western countries are also applicable to urban China.

Adult↗

PubMed2006

Visualization study on sedimentation of micron iron oxide particles.

In this paper, a novel technique combined light-electronic microscopy and computer imaging trace was used for visualization of the sedimentation of micron iron oxide particles in a customized micro-reactor. Micron iron oxide particles were recovered from the cinder of sulfuric acid production by sedimentation separating and hydraulic rating. Effects of particle size, shape and surface roughness on the sedimentation velocity were investigated. For irregular-shape particles, the sedimentation velocity and the geometric parameters of the particles were measured by the imaging trace technique. A correction coefficient (c) was used to modify the Stokes equation. In this study, the relationship between the correction coefficient and the equivalent diameter (d(p)) was found to be linear: c=0.6272-0.0298d(p), for iron oxide particles with equivalent diameter 4-22 microm.

Journal Article↗

PubMed2006

Regulation of contraction kinetics in skinned skeletal muscle fibers by calcium and troponin C.

The influences of [Ca(2+)] and Ca(2+) dissociation rate from troponin C (TnC) on the kinetics of contraction (k(Ca)) activated by photolysis of a caged Ca(2+) compound in skinned fast-twitch psoas and slow-twitch soleus fibers from rabbits were investigated at 15 degrees C. Increasing the amount of Ca(2+) released increased the amount of force in psoas and soleus fibers and increased k(Ca) in a curvilinear manner in psoas fibers approximately 5-fold but did not alter k(Ca) in soleus fibers. Reconstituting psoas fibers with mutants of TnC that in solution exhibited increased Ca(2+) affinity and approximately 2- to 5-fold decreased Ca(2+) dissociation rate (M82Q TnC) or decreased Ca(2+) affinity and approximately 2-fold increased Ca(2+) dissociation rate (NHdel TnC) did not affect maximal k(Ca). Thus the influence of [Ca(2+)] on k(Ca) is fiber type dependent and the maximum k(Ca) in psoas fibers is dominated by kinetics of cross-bridge cycling over kinetics of Ca(2+) exchange with TnC.

Animals↗

PubMed2005

Bending effect on fiber acousto-optic mode coupling.

The acousto-optic effect in a bent fiber is studied experimentally and numerically by using the scalar finite-element method. The resulting transmission spectra show that new mode-coupling peaks appear due to the breaking of the mode spatial symmetry. The strength of new peaks increases as the fiber-bending curvature increases with a redshift or blueshift in wavelength, strongly depending on the orientation of fiber bending with respect to the acoustic-wave vibration direction.

Acoustics↗

PubMed2005

The impact of childhood and adult SES on physical, mental, and cognitive well-being in later life.

OBJECTIVES: To examine the relationships between socioeconomic status (SES) and health across the life course and their variations by gender and race/ethnicity. METHODS: The sample included 19,949 respondents aged 50 or over from the 1998 Health and Retirement Study. RESULTS: Lower childhood SES was associated with worse health outcomes in later life. Part of the effect of childhood SES on adult health occurred through childhood health. The impact of childhood SES on education and income in adulthood explained an even larger share of this effect. We also found a stronger effect of adult SES for those with lower childhood SES than for those with more advantaged childhoods. Moreover, childhood SES had a similar impact on health in later life for women and men and for Whites and non-Whites. However, college education seemed more important for women's later health, whereas income seemed more important for men's health. Education appeared to have a weaker effect on adult health for Blacks and Hispanics than for Whites. DISCUSSION: Both childhood and adult SES are important for health. The negative impact of low childhood SES can be partially ameliorated if people from a low SES position during childhood mobilize to higher status in adulthood.

Aged↗

PubMed2005

Widening social inequalities in risk for sudden infant death syndrome.

OBJECTIVES: In 1994, the US Public Health Service launched the "Back to Sleep" campaign, promoting the supine sleep position to prevent sudden infant death syndrome (SIDS). Studies of SIDS in the United States have generally found socioeconomic and race disparities. Our objective was to see whether the "Back to Sleep" campaign, which involves an effective, easy, and free intervention, has reduced social class inequalities in SIDS. METHODS: We conducted a population-based case-cohort study during 2 periods, 1989 to 1991 and 1996 to 1998, using the US Linked Birth/Infant Death Data Sets. Case group was infants who died of SIDS in infancy (N = 21 126); control group was a 10% random sample of infants who lived through the first year and all infants who died of other causes (N=2241218). Social class was measured by mother's education level. RESULTS: There was no evidence that inequalities in SIDS were reduced after the Back to Sleep campaign. In fact, odds ratios for SIDS associated with lower social class increased between 1989-1991 and 1996-1998. The race disparity in SIDS increased after the Back to Sleep campaign. CONCLUSIONS: The introduction of an inexpensive, easy, public health intervention has not reduced social inequalities in SIDS; in fact, the gap has widened. Although the risk of SIDS has been reduced for all social class groups, women who are more educated have experienced the greatest decline.

Adult↗

PubMed2004

Wide-angle beam splitting by use of positive-negative refraction in photonic crystals.

We present a positive-negative refraction effect in which, under certain conditions, an incident plane wave launched into a photonic crystal excites a positive-refracted Bloch wave and a negative-refracted Bloch wave simultaneously, both of which maintain the polarization. By utilizing this phenomenon, wide-angle beam splitting can be realized at the microscale level. Numerical simulations are employed to demonstrate this anomalous refraction behavior.

Journal Article↗

PubMed2004

Intimate partner violence in China: national prevalence, risk factors and associated health problems.

CONTEXT: Intimate partner violence has been studied in many developed and developing countries. China remains one of the few large societies for which the prevalence and correlates of intimate partner violence are unknown. METHODS: Data from a nationally representative sample of women and men aged 20-64 with a spouse or other steady partner provide estimates of intimate partner violence in China. Binomial and multinomial logistic regression analyses adjusted for sample design examine risk factors and negative outcomes associated with partner violence. RESULTS: Altogether, 34% of women and 18% of men had ever been hit during their current relationship; the prevalence of hitting resulting in bleeding, bruises, swelling, or severe pain and injuries was 12% for women and 5% for men. Significant risk factors for partner violence included sexual jealousy, patriarchal beliefs, low female contribution to household income, low male socioeconomic status, alcohol consumption and residence in regions other than the South and Southeast. Severe hitting was a significant risk factor for self-reported adverse general and sexual health outcomes, including sexual dysfunction, sexual dissatisfaction and unwanted sex. CONCLUSIONS: As in other societies, intimate partner violence in China is common and is correlated with adverse general and sexual health outcomes.

Adult↗

PubMed2003

Myofibrillar determinants of rate of relaxation in skinned skeletal muscle fibers.

The influence of Ca2+ dissociation rate from TnC and decreased cross-bridge detachment rate on the time course of relaxation induced by flash photolysis of diazo-2 in rabbit skinned psoas fibers was investigated at 15 degrees C. A TnC mutant (M82Q TnC) that exhibited increased Ca2+ sensitivity caused by a decreased Ca2+ dissociation rate in solution also increased the Ca2+ sensitivity of force and decreased the rate of relaxation in fibers approximately 2-fold. In contrast, a TnC mutant (NHdel TnC) with decreased Ca2+ sensitivity caused by an increased Ca2+ dissociation rate in solution decreased Ca2+ sensitivity of force but did not accelerate relaxation. Decreasing the rate of cross-bridge kinetics by reducing [Pi] slowed relaxation -2-fold and led to two phases of relaxation, a linear phase followed by an exponential phase. In fibers, M82Q TnC further slowed relaxation in low [Pi] approximately 2-fold whereas NHdel TnC had no significant effect on relaxation. These results are consistent with the interpretation that the Ca2+ dissociation rate and cross-bridge detachment rate are similar in fast twitch skeletal muscle such that decreasing either rate slows relaxation but accelerating Ca2+ dissociation has little effect on relaxation.

Animals↗

PubMed2003

Heterologous expression of human cytochrome P450 2E1 in HepG2 cell line.

AIM: Human cytochrome P-450 2E1 (CYP2E1) takes part in the biotransformation of ethanol, acetone, many small-molecule substrates and volatile anesthetics. CYP2E1 is involved in chemical activation of many carcinogens, procarcinogens, and toxicants. To assess the metabolic and toxicological characteristics of CYP2E1, we cloned CYP2E1 cDNA and established a HepG2 cell line stably expressing recombinant CYP 2E1. METHODS: Human CYP2E1 cDNA was amplified with reverse transcription-polymerase chain reaction (RT-PCR) from total RNAs extracted from human liver and cloned into pGEM-T vector. The cDNA segment was identified by DNA sequencing and subcloned into a mammalian expression vector pREP9. A transgenic cell line was established by transfecting the recombinant plasmid of pREP9-CYP2E1 to HepG2 cells. The expression of CYP2E1 mRNA was validated by RT-PCR. The enzyme activity of CYP2E1 catalyzing oxidation of 4-nitrophenol in postmitochondrial supernate (S9) fraction of the cells was determined by spectrophotometry. The metabolic activation of HepG2-CYP2E1 cells was assayed by N-nitrosodiethylamine (NDEA) cytotoxicity and micronucleus test. RESULTS: The cloned CYP2E1 cDNA segment was identical to that reported by Umeno et al (GenBank access No. J02843). HepG2-CYP2E1 cells expressed CYP2E1 mRNA and had 4-nitrophenol hydroxylase activity (0.162 +/- 0.025 nmol.min(-1).mg(-1) S9 protein), which were undetectable in parent HepG2 cells. HepG2-CYP2E1 cells increased the cytotoxicity and micronucleus rate of NDEA in comparison with those of HepG2 cells. CONCLUSION: The cDNA of human CYP2E1 can be successfully cloned, and a cell line, HepG2-CYP2E1, which can efficiently express mRNA and has CYP2E1 activity, is established. The cell line is useful for testing the cytotoxicity, mutagenicity and metabolism of xenobiotics, which may possibly be activated or metabolized by CYP2E1.

Base Sequence↗

PubMed2002

Determinants of relaxation rate in rabbit skinned skeletal muscle fibres.

The influence of Ca(2+)-activated force, the rate of dissociation of Ca(2+) from troponin C (TnC) and decreased crossbridge detachment rate on the time course of relaxation induced by flash photolysis of diazo-2 in rabbit skinned psoas fibres was investigated at 15 degrees C. The rate of relaxation increased as the diazo-2 chelating capacity (i.e. free [diazo-2]/free [Ca(2+)]) increased. At a constant diazo-2 chelating capacity, the rate of relaxation was independent of the pre-photolysis Ca(2+)-activated force in the range 0.3-0.8 of maximum isometric force. A TnC mutant that exhibited increased Ca(2+) sensitivity caused by a decreased Ca(2+) dissociation rate in solution (M82Q TnC) also increased the Ca(2+) sensitivity of steady-state force and decreased the rate of relaxation in fibres by approximately twofold. In contrast, a TnC mutant with decreased Ca(2+) sensitivity caused by an increased Ca(2+) dissociation rate in solution (NHdel TnC) decreased the Ca(2+) sensitivity of steady-state force but did not accelerate relaxation. Decreasing the rate of crossbridge kinetics by reducing intracellular inorganic phosphate concentration ([P(i)]) slowed relaxation by approximately twofold and led to two phases of relaxation, a slow linear phase followed by a fast exponential phase. In fibres, M82Q TnC further slowed relaxation in low [P(i)] conditions by approximately twofold, whereas NHdel TnC had no significant effect on relaxation. These results are consistent with the interpretation that the Ca(2+)-dissociation rate and crossbridge detachment rate are similar in fast-twitch skeletal muscle, such that decreasing either rate slows relaxation, but accelerating Ca(2+) dissociation has little effect on relaxation.

Animals↗