Is a combined enforcement and penalty strategy effective in combating red light violations? An aggregate model of violation behavior in Hong Kong

Red light violations are a major cause of traffic crashes at signalized intersections. In Hong Kong, prosecutions for red light violations have increased in the past decade. An automated enforcement camera system has been established to combat this prohibited driver behavior. In addition, both demerit points and financial penalties were revised upwards in 2006 to strengthen the deterrent effect of the system. An observational study of driver tendency to run a red light was conducted to evaluate the effectiveness of the combined penalty and camera strategy. Both the short- and long-term effects of the strategy on red light violations were estimated. The influences of factors including temporal variation, the presence of a red light camera, geometric design, and traffic control type were also determined with an aggregate count data model. The results show that the frequency of red light violations significantly decreased after the implementation of the new penalty system, and that the reduction remained significant one year after implementation. Interestingly, no evidence was found for an association between the frequency of red light violations and the presence of a red light camera.

Effect of biosurfactant on the sorption of phenanthrene onto original and H2O2-treated soils

The objective of this study was to examine the effect of biosurfactant on the sorption of phenanthrene (PHE) onto the original or H2O2-treated black loamy soil (typic isohumisols) and red sandy soil (typic ferralisols). The sorption isotherms were performed with the original and "soft" carbon-removed soils in the presence and absence of biosurfactant (200 mg/L). The sorption and degradation of biosurfactant were investigated. The result showed that organic matter played an important role in PHE sorption onto the black loamy and red sandy soils, and the PHE sorption isotherms on the "soft" carbon-removed soils exhibited more nonlinearity than those on the original soils. The values of partition coefficient (Kd) on the original black loamy soil with or without 200 mg/L biosurfactant were 181.6 and 494.5 mL/g, respectively. Correspondingly, in the red sandy soil, Kd was 246.4 and 212.8 mL/g in the presence or absence of biosurfactant, respectively. The changes of Kd suggested that biosurfactant inhibited PHE sorption onto the black loamy soil, but facilitated PHE sorption onto the red sandy soil. The nonlinearity of PHE sorption isotherm was decreased in the presence of biosurfactant. Site specific sorption might occur during PHE sorption onto both the original and the "soft" carbon-removed soils in the presence of biosurfactant. It was noted that biosurfactant could also be sorbed onto soils. The maximal sorption capacity of the red sandy soil for biosurfactant was (76.9 +/- 0.007) microg/g, which was 1.31 times that of black loamy soil. Biosurfactant was degraded quickly in the two selected soils, and 92% of biosurfactant were mineralized throughout the incubation experiment for 7 d. It implied that biosurfactant should be added frequently when the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils was conducted through PAH desorption approach facilitated by biosurfactant.

Correlation of lens density measured using the Pentacam Scheimpflug system with the Lens Opacities Classification System III grading score and visual acuity in age-related nuclear cataract

AIMS

To investigate the relationship between lens density measured with the Pentacam Scheimpflug System and grading score using the Lens Opacities Classification System (LOCS) III as well as that between lens density and visual acuity in age-related nuclear cataract patients.

METHODS

Lens density and grading score were evaluated in 138 cases (180 eyes) with age-related nuclear cataract. LogMAR visual acuity was tested with the Early Treatment Diabetic Retinopathy Study chart. The correlations between lens density value and LOCS III nuclear opacity (NO) and nuclear colour (NC) grading score and that between lens density value and logMAR visual acuity were analysed.

RESULTS

There was a linear increasing relationship between lens density value and LOCS III grading score in nuclear cataract patients. Lens density value had a stronger significant correlation with LOCS III NO score than that with NC score. The correlation between the nuclear lens density value and logMAR visual acuity was stronger than that between NO score and logMAR visual acuity or between NC score and logMAR visual acuity.

CONCLUSION

Lens density as a quantitative and objective parameter can present the degree of NO and associated visual impairment due to nuclear cataract. The LOCS III criterion as an economic cataract grading system provides data that are in satisfactory concordance with the results obtained using the Pentacam Scheimpflug system.

Provincial income inequality and self-reported health status in China during 1991-7

BACKGROUND

The relationship between income inequality and health has been widely explored. Today there is some evidence suggesting that good health is inversely related to income inequality. After the economic reforms initiated in the early 1980s, China experienced one of the fastest-growing income inequalities in the world. The state of China in the 1990s is focussed on and possible effects of provincial income inequality on individual health status are explored.

METHODS

A multilevel regression model is used to analyse the data collected in 1991, 1993 and 1997 from nine provinces included in the China Health and Nutrition Survey. The effects of provincial Gini coefficients on self-rated health in each year are evaluated by two logistic regressions estimating the odds ratios of reporting poor or fair health. The patterns of this effect are compared among the survey years and also among different demographic groups.

RESULTS

The analyses show an independent effect of income inequality on self-reported health after adjusting for individual and household variables. Furthermore, the effect of income distribution is not attenuated when household income and provincial gross domestic product per capita are included in the model. The results show that there is an increased risk of about 10-15% on average for fair or poor health for people living in provinces with greater income inequalities compared with provinces with modest income inequalities.

CONCLUSIONS

In China, societal income inequality appears to be an important determinant of population health during 1991-7.

Humanin delays apoptosis in K562 cells by downregulation of P38 MAP kinase

Humanin (HN) is a newly identified neuroprotective peptide. In this study, we investigated its antiapoptotic effect and the potential mechanisms in K562 cells. Upon serum deprivation, expression of HN in K562 cells decreased and its intracellular distribution changed from cytoplasm to cell membrane. In HN stably transfected K562 cells, apoptosis was delayed compared with control vector transfected cells as measured by flow cytometry. Furthermore, analysis of different mitogen-activated protein (MAP) kinases activity revealed that extracellular signal-regulated kinase (ERK) pathway was inhibited while p38 signaling was activated following serum deprivation in K562 cells. And in HN transfected K562 cells, ERK downregulation was not affected, but p38 activation was suppressed, which may responsible for the delayed apoptosis in these cells. Activation of the ERK signaling pathway by phorbol myristate 13-acetate (PMA) and sorbitol protected K562 cells from serum deprivation induced apoptosis. Additionally, overexpression of HN reduced megakaryocytic differentiation of K562 cells. The present data outline the role of ERK and p38 MAP kinases in serum deprivation induced apoptosis in K562 cells and figure out p38 signaling pathway as molecular target for HN delaying apoptosis in K562 cells.

SU proteins from virulent and avirulent EIAV demonstrate distinct biological properties

Biologic activity of equine infectious anemia virus (EIAV) surface (SU) glycoprotein was assayed in a mouse model. Recombinant SU from virulent EIAV17 (SU17), administered intraperitoneally to mouse pups, induced dose-dependent diarrheal responses similar to those reported for SIV SU (Virology 277 (2000) 250). SU17 caused fluid accumulation without histological lesions in mouse intestinal loops, induced chloride secretory currents in Ussing chambers and increased inositol 1,4,5 triphosphate (IP3) levels in HT29 cells. An SU17 peptide, SU17(299-330), provoked a dose-dependent diarrheal response akin to enterotoxic peptides from SIV. In contrast, SU from an avirulent EIAV strain failed to induce a dose response in mouse pups and produced lower levels of activity than SU17 in Ussing chambers and IP3 assays. These results demonstrate that a mouse pup model is useful to monitor EIAV SU biologic activity, showing clear differences between the activities of SU derived from virulent and avirulent viruses, and may provide a useful screen of EIAV virulence.

Noise-induced impulse pattern modifications at different dynamical period-one situations in a computer model of temperature encoding

We used a minimal Hodgkin-Huxley type model of cold receptor discharges to examine how noise interferes with the non-linear dynamics of the ionic mechanisms of neuronal stimulus encoding. The model is based on the assumption that spike-generation depends on subthreshold oscillations. With physiologically plausible temperature scaling, it passes through different impulse patterns which, with addition of noise, are in excellent agreement with real experimental data. The interval distributions of purely deterministic simulations, however, exhibit considerable differences compared to the noisy simulations especially at the bifurcations of deterministically period-one discharges. We, therefore, analyzed the effects of noise in different situations of deterministically regular period-one discharges: (1) at high-temperatures near the transition to subthreshold oscillations and to burst discharges, and (2) at low-temperatures close to and more far away from the bifurcations to chaotic dynamics. The data suggest that addition of noise can considerably extend the dynamical behavior of the system with coexistence of different dynamical situations at deterministically fixed parameter constellations. Apart from well-described coexistence of spike-generating and subthreshold oscillations also mixtures of tonic and bursting patterns can be seen and even transitions to unstable period-one orbits seem to appear. The data indicate that cooperative effects between low- and high-dimensional dynamics have to be considered as qualitatively important factors in neuronal encoding.

[The study of beta-2 adrenergic receptors gene transferred into cardiomyocytes by adenovirus vectors contain different promoter]

OBJECTIVE

To observe human beta(2) adrenergic receptors (beta(2)-AR) gene expression in cardiomyocytes transfected by adenoviral vector contain cmv or mlc-2v promoter.

METHODS

Two adenoviral vectors (Adcmv beta(2) AR, Admlc beta(2) AR) were constructed, in which beta(2)-AR gene is under control of either the ventricle-specific myosin light chain-2 (mlc-2v) or the cmv promoter. The cultured neonate rat ventricular myocytes were infected by two adenoviral vectors, and the beta(2)-AR expression of on cultured neonate rat ventricular myocytes and their ability to potentiate beta-adrenergic signaling were assessed.

RESULTS

The presence of beta(2)-AR mRNA was detected by RT-PCR, and the expression of the beta(2)-AR gene was demonstrated by protein immunoblots. According to a ligand binding assay, the density of beta-AR in the cardiomyocytes infected by Admlc beta(2) AR and Adcmv beta(2) AR was greater than that in the control. Moreover, the latter was higher than the former (234 +/- 6.4 fmol/mg protein vs 153 +/- 5.2 fmol/mg protein) (P < 0.01). It was demonstrated that beta(2)-AR gene significantly increased isoproterenol stimulated cAMP in cardiomyocytes.

CONCLUSION

The results above demonstrated that human beta(2)-AR gene was expressed in the cardiomyocytes infected by recombinant adenovirus contain cmv or mlc-2v promoter, but both is different.

[Expression of recombinant human Flt3 ligand in Escherichia coli and its purification and characterization]

OBJECTIVE

To establish a highly efficient expression system of recombinant human Flt3 ligand (rhFL) in E. coli and a suitable purification method of the expressed products.

METHOD

Human FL encoding cDNA was introduced into pProEXHT plasmid to express a 6 x His-FL fusion protein in E. coli. The fusion protein expressed in inclusion body was isolated, solubilized and refolded, and then purified by chromatography on a metal-chelating affinity column (MCAC). Its activity was detected by stimulating the proliferation of CD(34)(+) cells.

RESULT

The amount of rhFL expressed was about 15% of total bacterial proteins and the purity of rhFL was 90% after MCAC. The combination of rhFL, granulocyte colony-stimulating factor and erythropoietin could stimulate CD(34)(+) cells to a 400 fold expansion.

CONCLUSION

The purified rhFL had a potent activity to stimulate hematopoietic stem cells to expanse in vitro.

Paddlefish strike at artificial dipoles simulating the weak electric fields of planktonic prey

The freshwater paddlefish Polyodon spathula (Polyodontidae) feeds primarily on the water flea (Daphnia sp.), and previous studies suggest that these fish detect their planktonic prey using their rostral electrosensory system. Zooplankton produce direct-current and oscillating alternating-current electric fields containing multiple frequencies and amplitudes. We asked whether an inanimate electric field is sufficient to elicit paddlefish strikes equivalent to their feeding behavior. Juvenile paddlefish respond to artificial dipole stimuli by investigating the electric field and striking at the dipole electrode tips. These behavioral responses, scored as strikes, exhibit a bandpass characteristic with a maximum response between 5 and 15 Hz. Responses were less frequent at higher (20, 30, 40, 50 Hz) and lower (0.1, 0.5, 1 Hz) test frequencies, with a steep drop-off below 5 Hz. Strike rates also varied with stimulus intensity. Response frequency was greatest at 0.25 microA peak-to-peak amplitude, with reduced responses at lower and higher amplitudes (0.125 and 1.25 microA). Striking behavior was also influenced by water conductivity: strike rate was reduced at higher water conductivity. Dipole-elicited strikes exhibit behavioral plasticity. Fish habituate to repetitive dipole stimuli that are not reinforced by prey capture, and they dishabituate after food reinforcement. These experiments characterize paddlefish feeding strikes towards dipole electrodes at signal frequencies and intensities simulating the electric fields of zooplankton, their natural prey, and demonstrate that electric fields are sufficient to elicit feeding behavior. The results support the conclusion that paddlefish use their passive electrosensory system for planktivorous feeding.

[Expression of lipofect AMINE mediated human GM-CSF eukaryotic expressing vector in HFCL cells]

OBJECTIVE

To construct an eukaryotic expressing vector-pIRES1neo/hGM-CSF and express it in human bone marrow stromal cell line HFCL.

METHODS

Human granulocyte/macrophage colony-stimulating factor cDNA (hGM-CSF cDNA, 751 bp) was inserted into an effective eukaryotic expressing vector-pIRES1neo which contains the human cytomegalovirus (CMV) major immediate early promoter/enhancer and the internal ribosome entry site (IRES) of the encephalomyocarditis virus (ECMV). HFCL cells were transfected with the recombinant vector pIRES1neo/hGM-CSF by liposome-mediated gene transfer method. Integration of hGM-CSF in the genome, transcription of its mRNA and expression of its protein in the transfected HFCL cells were assayed by Southern blot, Northern blot, ELISA and hGM-CSF dependent cell line TF-1.

RESULTS

hGM-CSF cDNA was integrated into HFCL genome successfully, hGM-CSF mRNA was transcripted and hGM-CSF protein was expressed of (56.9 +/- 0.7) ng/10(6) cells by ELISA and (6.56 +/- 0.16) x 10(3) U/10(6) cells per day by TF-1 cell assay in the supernatant.

CONCLUSION

The recombinant vector is proved to be stably expressed in HFCL cells and the biological activity of hGM-CSF was detectable in the supernatant of the transfected cells.

[Experimental studies on the characteristics of suicide gene system HSV-tk/GCV and its effect on dendritic cells]

OBJECTIVE

To study the characteristics of suicide gene system of the herpes simplex virus thymidine kinase (HSV-tk) gene in tumor cells and explore the apoptosis phenomena in this system and its effect on dendritic cells (DC).

METHOD

HSV-tk was transduced into the breast cancer cell line MCF-7 cells with a retrovirus vector. Apoptosis was examined by electro-microscopy and FACS. DCs were induced from cord blood CD(34)(+) cells with a combination of cytokines (GM-CSF, TNF-alpha, SCF and FL) and (3)H-TdR was adopted to determine the proliferation of T cells.

RESULTS

In vitro experiment showed a dose-dependent cell killing of the HSV-tk gene transducted cells on ganciclovir (GCV) treatment. The apoptosis rate increased to 31.3% from the control group of 19.3%. Apoptosis is the important mechanism in bystander effect of HSV-tk/GCV system. The CD(1a)(+) and HLA-DR(+) cells in the induced DC were of (27.18 +/-1.56)% and (93.7 +/- 1.0)%, respectively. Co-incubation of DC with apoptotic cells further stimulated the proliferation of T cells.

CONCLUSION

It suggested that HSV-tk/GCV system, alone or combined with radiotherapy, be a promising suicide gene therapy for cancer patient and an approach to enhancing DC function.