Cavity-QED assisted attraction between a cavity mode and an exciton mode in a planar photonic-crystal cavity

The photoluminescence spectra from a quantum-dot exciton weakly-coupled to a planar photonic-crystal cavity is experimentally investigated by temperature tuning. Significant resonance shifts of the cavity mode are observed as the cavity mode spectrally approaches that of the exciton mode, showing the appearance of cavity-to-exciton attraction or mode pulling. Cavity-mode spectral shifts are also found theoretically using a master equation model that includes incoherent pump processes for the coupled exciton and cavity, pure dephasing, and allows for photon emission via radiation modes and the leaky cavity mode. Both experiments and theory show clear cavity mode spectral shifts in the photoluminescence spectra, when certain coupling parameters are met. However, discrepancies between the experimental data and theory, including more pronounced spectral shifts in the measurements, indicate that other unknown mode-pulling effects may also be occurring.

Comparison of risk factors associated with hypertension subtypes by classification tree method in Tongshan County of Jiangsu Province, China

BACKGROUND

There are only a very limited number of studies relating to risk factors for hypertension in rural populations in China. There are even fewer studies comparing various hypertension subtypes.

METHODS

A cross-sectional investigation was carried out in a representative sample of 20,390 subjects drawn from among 1,180,000 adult residents of Tongshan County of Jiangsu Province, China. The impact of risk factors including demographic, socioeconomic, dietary, and behavioral, on three hypertension subtypes, namely, isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic-diastolic hypertension (SDH), was analyzed by applying statistical tests and a classification tree.

RESULTS

ISH was the predominant untreated hypertension subtype (13.68 +/- 0.24%) in the adults of Tongshan County, followed by SDH (11.70 +/- 0.23%) and IDH (6.24 +/- 0.17%). Age, number of cigarettes smoked daily, and the types of vitamins taken varied among the ISH, IDH, and SDH classification trees. Low socioeconomic status was associated with an increased risk for ISH and SDH. Light alcohol intake was associated with higher risk for ISH, but with lower risks for IDH and SDH. Light cigarette smoking was associated with higher ISH risk but lower SDH risk. The intake of appropriate amounts of fish, shrimp, or meat lowered the risks for ISH and IDH. The intake of appropriate amounts of seafood, eggs, milk, or fruit lowered the risks for all hypertension subtypes. Interestingly, an excessive preference for sweet or salty foods was associated with a higher risk for all the subtypes.

CONCLUSIONS

In Tongshan County, there was a considerable prevalence of hypertension of various subtypes, each associated with distinctive and complex risk factors. This suggests that there is a need for testing more diverse prevention measures, tailored to specific subtypes.

Macroscopic entanglement and violation of Bell's inequalities between two spatially separated quantum dots in a planar photonic crystal system

We present and apply a medium-dependent quantum optics formalism for describing the exciton dynamics of two spatially-separated quantum dots on-chip, in the regime of coupled-cavity quantum electrodynamics. With each dot placed in a spatially-separated cavity and coupled through a periodic waveguide channel, the quantum dot excitons behave as a composite entangled pair, exhibiting pronounced entanglement over distances of 300 microm and more. The computed light spectra above the two cavities show clear signatures of pronounced photon coupling including increased vacuum Rabi splitting and cavity-induced transmission and absorption. The macroscopic entanglement is confirmed by investigating the Bell inequality, which is shown to be violated for hundreds of picoseconds.

Theory of quantum light emission from a strongly-coupled single quantum dot photonic-crystal cavity system

We present a rigorous medium-dependent theory for describing the quantum field emitted and detected from a single quantum dot exciton, strongly coupled to a planar photonic crystal nanocavity, from which the exact spectrum is derived. By using simple mode decomposition techniques, this exact spectrum is subsequently reduced to two separate user-friendly forms, in terms of the leaky cavity mode emission and the radiation mode emission. On application to study exciton-cavity coupling in the strong coupling regime, besides a pronounced modification of the usual vacuum Rabi spectral doublet, we predict several new effects associated with the leaky cavity mode emission, including the appearance of an off-resonance cavity mode and a loss-induced on-resonance spectral triplet. The cavity mode emission is shown to completely dominate the emitted spectrum, even for large cavity-exciton detunings, whereby the usual cavity-QED formulas developed for radiation-mode emission drastically fail. These predictions are in qualitative agreement with several "mystery observations" reported in recent experiments, and apply to a wide range of semiconductor cavities.

Effect of vitamin A supplementation on immune function of well-nourished children suffering from vitamin A deficiency in China

OBJECTIVE

To clearly clarify the protective effect of vitamin A supplementation on immune function of well-nourished children suffering from vitamin A deficiency.

METHODS

Three hundred sixty-two children in two kindergartens in Wuhan China were enrolled. Detailed dietary assessment and anthropometry were undertaken to facilitate the exclusion of malnourished children. Seventy vitamin A-deficient children with informed consent were randomly divided into the vitamin A-deficient-supplemented group and vitamin A-deficient placebo group, 35 vitamin A-sufficient children (age- and sex-matched with the vitamin A-deficient-supplemented group children) were selected as vitamin A-sufficient placebo group. The baseline and follow-up level of selected immune parameters of the 105 children in three intervention groups were compared.

RESULTS

The total proportion of severe and marginal vitamin A-deficient children was 10.9 and 21.96%, respectively. At baseline, the serum complement C3 and sIgA level of vitamin A-sufficient children was significantly higher than that of vitamin A-deficient children (P < 0.05). However, the serum lysozyme level of vitamin A-sufficient children was inversely lower. After intervention, vitamin A-deficient-supplemented children increased serum vitamin A, complement C3 and sIgA level, but their serum lysozyme level inversely decreased.

CONCLUSIONS

Vitamin A deficiency was still a serious health problem in children in China cities. Vitamin A supplementation was efficacious in ameliorating serum vitamin A status and partially impaired immune function of well-nourished children suffering from vitamin A deficiency.

A low-cost, sustainable intervention for drinking reduction in the HIV primary care setting

Excess drinking poses multiple substantial health risks to HIV-infected individuals. However, no published intervention studies have focused on drinking reduction as the main outcome in HIV primary care patients. An intervention in this setting must place minimal demands on pressured staff and resources. This pilot study tested such an intervention, which consisted of brief Motivational Interviewing (MI) and HealthCall, an automated daily telephone self-monitoring system based on Interactive Voice Response (IVR), designed to extend and enhance the effects of brief MI. Thirty-one patients entered the study, received a 30-minute MI and were instructed in daily use of the IVR system. They received graphical feedback on their daily drinking from the HealthCall database after 30 days. A statistically significant decrease in drinking was found over time, both as reported in daily IVR calls (beta = - 0.01, se 0.01, p=.03) and in follow-up interviews (beta = - 0.04, se 0.12, p=.02) at 60 days. The proportion of daily calls made supported the feasibility of the intervention. The results indicate that HealthCall is acceptable to a disadvantaged HIV patient population, and preliminary data support the efficacy of this intervention in reducing harmful drinking among HIV primary care patients.

[Studies on the experimental transmission of Rattus-borne Hantavirus by Ornithonyssus bacoti]

AIM

To demonstrate the role of rat mite (Ornithonyssus bacoti) in the transmission of Rattus-borne hemorrhagic fever with renal syndrome (HFRS).

METHODS

In the transmission experiments, about 100 O. bacoti per pool were isolated and placed in a jar, unfed for 4 d at 23 +/- 1 degrees C. Suckling Wistar rats inoculated with Hantavirus strain Z45 or Seoul virus strain UR were placed in each jar for free attack by the mites for 12 hours. After 14 d the normal suckling Wistar rats were bitten by the mites. Fifteen days later, the lung tissues and sera of the infected rats were collected and detected for Hantaviral antigen by indirect fluorescent antibody technique (IFAT). For demonstration of the infection of O. bacti with Rattus-borne Hantavirus PCR technique was applied to detect Rattus-borne Hantaviral RNA.

RESULTS

Sukling Wistar rats inoculted Hantavirus strain Z45 or Seoul virus strain UR were bitten by O. bacoti and then these mites were fed on 4 and 5 of normal suckling rats in each jar, respectively. The antigens of Hantavirus strain Z45 were positive in all the lungs of the normal rats bitten by the mites, the sera titers of the rats were from 1:10 to 1:40. The antigens were positive in 3 of the 4 rats, the sera titers were from 1:20 to 1:40. Both of the viruses could be maintained in O. bacoti for 22 days. The blocking test showed when 1:30 Hantavirus immunosera were exposed to the lung samples and then reacted with the sera from the patients with HFRS, all the specific fluorescence reactions of the samples were blocked, whereas the control group including the normal rat lung tissues and sera were all negative (Fig. 1).

CONCLUSION

O. bacoti might play a role as the vector of HFRS and a reservoir host as well.

Taxane diterpenoids from the bark of Taxus yunnanensis

Further investigation on the alcohol extract of the barks of Taxus yunnanensis led to the isolation of four taxoids, namely, 7beta-xylosyl-taxol D, taxuyunnanines P, Q and R, along with the known taxuyuntin G (2). Four are rearranged taxoids with an 11(15-->1)-abeotaxoid skeleton and an opened oxetane ring moiety. Structures were determined by spectroscopic and chemical means.

[Study on the noninvasive measurement of cerebral oxygen saturation and cerebral phronetal function]

With the use of Near-infrared spectroscopy(NIRS), the noninvasive measurement of cerebral oxygen concentration can be achieved in vivo based on the Lambert-Beer Law. In this paper, we discuss the possibility of studying higher brain functions through a combination of cerebral oxygen saturation and cerebral function measurement. Event-related experiments are introduced to measure the cerebral phronetal function. Time domain curves show sight differences among these experiment results. However, with the aid of DFT, experiment data of all five human volunteers show that the frequency near 20 Hz or 40 Hz is evoked depending on the difficulty of the mental tasks. The results demonstrate the feasibility of cerebral function studies by means of cerebral oxygen saturation measurement analysis in the frequency domain.

Hepatitis C virus infection and morphologic study in B lymphocytes of patient with hepatitis C

OBJECTIVE

To study hepatitis C virus (HCV) infection in B lymphocytes of patients with hepatitis C and to establish a B cell line with HCV infection and observe the hepatitis C virus like particles.

METHODS

A B lymphoblastoid cell line was established by Epstein-Barr virus induced transformation directly from peripheral blood mononuclear cells of a patient with hepatitis C. The HCV antigen and HCV RNA were detected by immunohistochemical technique. Reverse transcription-polymerase chain reaction(RT-PCR) and in situ hybridization and HCV particle were detected by electron microscopy.

RESULTS

Positive HCV RNA was found in supernatants of B cell line. HCV Ag and HCV RNA were also showed positive. Electron microscopy observed HCV spherical virus like particles with a diameter of approximately 65 nm and 110 nm and the "bud mutation" of HCV in the cytoplasmic vesicles of B lymphocytes.

CONCLUSIONS

HCV could infect B lymphocytes and replicate in the cell line. HCV particles are formed by "bud mutation" of HCV in the cytoplasmic vesicles of B-lymphocytes.

Rearranged taxanes from the bark of Taxus yunnanensis

Five new 11(15-->1)-abeo-taxane diterpenoids, taxuyunnanines K-O (1-5), were isolated from an ethanol extract of the bark of Taxus yunnanensis, and their structures were determined using MS and NMR techniques. Compounds 1/2 and 4/5 are rearranged taxane diterpenoids possessing an opened oxetane ring moiety at C4(20). Compounds 4/5 are rearranged taxoids lacking an oxygenated functionality at C-4.

[Study of hepatitis C virus specific immune responses in anti-HCV positive patients without hepatitis C viremia]

OBJECTIVE

To study the hepatitis C virus specific immune responses in anti - HCV positive patients without hepatitis C viremia.

METHODS

15 anti-HCV positive patients without hepatitis C viremia, 15 patients with chronic HCV infection and 15 normal controls were selected for this study. The T cell responses, NK cell (natural killer cells) activity, cytokine production and HCV specific antibodies were detected by MTT, LDH release and ELISA.

RESULTS

Our study showed that the T cell proliferative reaction of patients without hepatitis C viremia was significantly higher than that of patients with chronic HCV infection and normal controls and the T cell response for HCV core antigen were higher than NS3 and N54, but there was no significant proliferative response to NS5 antigen. We also found that there were no differences in anti-HCV antibody production and NK cell activity between the two groups and the level of IFN-gamma in patients without hepatitis C viremia was higher than that in patients with persistent HCV infection.

CONCLUSIONS

There are a lot of advantageous changes of HCV specific humoral and cellular immune response in anti-HCV positive patients without hepatitis C viremia, these immune responses may play a role in clearance of HCV.

[Assessment on acute toxicity of combined pesticides]

The acute oral toxicity (LD50) of two pesticides combined from 3 categories of insecticides, i.e. organophosphates(OPs), pyrethroids and carbamates, was evaluated by Harris method on equal toxicity doses. The OPs compounds studied included: methylparathion, omethoate, methamidophos, phoxim, dichlorvos, profenofos, isocarbophos and malathion; the pyrethroids: alpha-cypermethrin, deltamethrin, fenvalerate and fenpropathrin; the carbamates: methomyl, isoprocarb and metolcarb. The mixtures of two OPs on the combination of dichlorvos plus omethoate and methamidophos plus profenofos showed additive effects, but methylparathion plus phoxim showed antagonistic effect. Most of the combination of OPs with pyrethroids showed synergistic effects, such as the mixtures of phoxim plus deltamethrin, phoxim plus alpha-cypermethrin, methlyparathion plus alpha-cypermethrin and ioscoarbphos plus fenpropthrin, with the exception of two mixtures showed additive effects: phoxim plus fenvalerate resulting in 1.5 times higher toxicity than expected, while dichlorvos plus deltamethrin resulting in less toxicity than expected. The effects of the mixtures of OPs and carbamates: phoxim plus methomyl and methamidophos plus metolcarb, were all additive, but the mixtures of he methylparathion plus methomyl showed antagonistic effect and malathion plus isoprocarb were synergistic. The biochemical mechanisms of changed toxicity of pesticides mixtures were discussed based on their toxicokinetics and toxicodynamics. It was concluded that the combined effects of insecticide mixtures were additive for OPs plus OPs or plus carbamates in most cased, but synergistic for OPs plus pyrethroids.

Effect of mutation at valine 61 on the three-dimensional structure, stability, and redox potential of cytochrome b5

To elucidate the role played by Val61 of cytochrome b(5), this residue of the tryptic fragment of bovine liver cytochrome b(5) was chosen for replacement with tyrosine (Val61Tyr), histidine (Val61His), glutamic acid (Val61Glu), and lysine (Val61Lys) by means of site-directed mutagenesis. The mutants Val61Tyr, Val61Glu, Val61His, and Val61Lys exhibit electronic spectra identical to that of the wild type, suggesting that mutation at Val61 did not affect the overall protein structure significantly. The redox potentials determined by differential pulse voltammetry were -10 (wild type), -25 (Val61Glu), -33 (Val61Tyr), 12 (Val61His), and 17 mV (Val61Lys) versus NHE. The thermal stabilities and urea-mediated denaturation of wild-type cytochrome b(5) and its mutants were in the following order: wild type > Val61Glu > Val61Tyr > Val61His > Val61Lys. The kinetics of denaturation of cytochrome b(5) by urea was also analyzed. The first-order rate constants of heme transfer between cytochrome b(5) and apomyoglobin at 20 +/- 0.2 degrees C were 0.25 +/- 0.01 (wild type), 0.42 +/- 0.02 (Val61Tyr), 0.93 +/- 0.04 (Val61Glu), 2.88 +/- 0.01 (Val61His), and 3.88 +/- 0.02 h(-)(1) (Val61Lys). The crystal structure of Val61His was determined using the molecular replacement method and refined at 2.1 A resolution, showing that the imidazole side chain of His61 points away from the heme-binding pocket and extends into the solvent, the coordination distances from Fe to NE2 atoms of two axial ligands are approximately 0.6 A longer than the reported value, and the hydrogen bond network involving Val61, the heme propionates, and three water molecules no longer exists. We conclude that the conserved residue Val61 is located at one of the key positions, the "electrostatic potential" around the heme-exposed area and the hydrophobicity of the heme pocket are determinant factors modulating the redox potential of cytochrome b(5), and the hydrogen bond network around the exposed heme edge is also an important factor affecting the heme stability.

Discordance between physicians and coders in assignment of diagnoses

OBJECTIVE

To measure concordance between physicians and medical record coders in their assignment of diagnoses.

DESIGN

Prospective cohort series.

SETTING

Five hundred and fifty-bed, tertiary-care, university teaching hospital. Study participants. In-patients who were discharged from either the Cardiac Sciences Program (n=125), the Renal Program (n=43), or the HIV-AIDS Program (n=25) during the period May 18-July 1, 1995.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Physicians and coders assigned diagnoses for individual in-patients based on their independent interpretations of the patient chart and discharge summary sheet. All assigned diagnoses were coded using the ICD-9-CM classification system. Concordance was measured for the most responsible diagnosis and for all assigned diagnoses. Difference in calculated resource intensity weights based on physicians' and coders' assignment of diagnoses was also calculated.

RESULTS

Concordance rates for the most responsible diagnosis in each program were: Cardiac Sciences [27%; 95% confidence interval (CI)=20-36%], Renal Program (35%; 95% CI=21-53%), and HIV-AIDS Program (20%; 95% CI, 6-41%). Concordance rates for all diagnoses per chart were similar: Cardiac Sciences (20%; 95% CI, 14-25%), Renal Program (25%; 95% CI, 20-33%), and HIV-AIDS Program (29%; 95% CI, 25-44%). Resource intensity weights assigned by coders for the Cardiac Sciences and HIV-AIDS Program were significantly higher than those assigned by the physicians.

Anti-aging effects of Bao-Chun-Wan on rats: a morphological ultrastructure study

Bao-Chun-Wan, a Chinese prescription, is formulated according to the principle of tonifying the kidney for treatment of aging. Morphological study on the ultrastructure of laboratory albino rats treated with this formula showed an increase in thymic lymphocytes, which play an important role in the production of T cells. As to the liver cells, the formula has a protective effect and may induce enzymes enhancing oxidation and excretion of toxic substances. An increase in the Leydig's cell, which promotes reproductive hormone secretion, was also observed, but there was no obvious change in germinal cells. The above findings reported in this article have not been cited in any previous studies and are suggesting that the kidney tonifying formula may act through the mechanism of promoting body immune function, metabolism and biotransformation, and, therefore, result in anti-aging.

Importance of a conserved phenylalanine-35 of cytochrome b5 to the protein's stability and redox potential

Phenylalanine-35, which is a residue of the hydrophobic patch on the surface of cytochrome b5, has been mutated into Tyr35, His35 and Leu35 to elucidate the functions of the Phe35 and give further insight into the roles of the hydrophobic patch and/or aromatic network. The effects of these mutations on the heme environment, denaturation towards heating and the denaturant urea, redox potential and stability of protein were studied. The relative stability of cytochrome b5 and its mutants towards heating has the order Phe35Tyr > wild type > Phe35Leu > Phe35His in the oxidized state and wild type > Phe35Tyr > Phe35Leu > Phe35His in the reduced state. All the mutants exhibit decreased reduction potentials: Phe35Tyr -66 mV, Phe35His -51 mV and Phe35Leu -28 mV, which are more negative than that of the wild type. The order of redox potential reflects the relative stability in the oxidized and reduced states. A method of producing multiple mutants at a single site of a gene is also described for the first time.

Postmortem cryosectioning as an anatomic reference for human brain mapping

This study examined the densitometric and topographic detail of high resolution 3D digital postmortem cryosectioned brain images. Anatomic image data and histology from cryosectioned human brain were compared to in vivo MRI for the ability to delineate neuroanatomic structure. 3D surface reconstructions in the Talairach and Tournoux atlas ("Co-planar stereotaxic atlas of the human brain", Thieme, New York, 1988) coordinate system enabled morphometric comparisons for a representative sample of neuroanatomic structures. Spatial resolution of cryosection images averaged 200 and 170 microns/pixel for whole head and brain, respectively, and 40 microns/pixel for isolated the brain regions. Anatomic detail was far superior to MRI, particularly in deep subcortical regions such as the basal ganglia and in mesencephalic nuclei and tracts. Digital repositioning in the Talairach coordinate system enabled efficient structure localization and morphometric comparison. Histology from collected tissue sections provided cytologic detail that could be mapped to its approximate 3D context. This approach permits comprehensive morphometric analyses necessary for an anatomic framework to a digital atlas of the human brain.

Methyltransferase-specific domains within VP-39, a bifunctional protein that participates in the modification of both mRNA ends

VP39 is a bifunctional vaccinia virus protein that acts as both a cap- dependent 2'-O-Methyltransferase and a poly(A) polymerase processivity factor. An analysis of C-terminal truncation mutants of a GST-VP39 fusion protein indicated the presence of a protease-sensitive C-terminal "tail" 36-43 amino acids in length that is non-essential for VP39 function. Fourteen new VP39 pointmutants, containing either single or multiple-clustered amino acid substitutions, were expressed in Escherichia coli. Of the eight that retained either one or both of the activities of VP39, seven were specifically methyltransferase-defective. None was specifically defective in adenylyltransferase stimulation. The nature of the methyltransferase defects in 10 of the methyltransferase-specific defectives, identified both herein and in a previous study (Schnierle BS, Gershon PD, Moss B, 1994, J biol Chem 269:20700-20706), was investigated using two novel substrate-binding assays. Three of the mutants (and possible a fourth), whose lesions were juxtaposed and centrally located within VP39, exhibited anomalous S-adenosyl-(L)-methionine (AdoMet) binding behavior, identifying residues important for AdoMet binding and possible also for catalysis. A surface plasmon resonance-based assay measured the interaction of VP39 with uncapped and 5'-cap 0-terminated oligo(A). A cap 0- dependent association-rate enhancement was observed for wild-type VP39 and 4 of the 10 mutant proteins. Two others were identified as defective in cap binding, and a third as partially defective. The lesions within the latter three mutants were closely apposed, and located toward the N-terminus of VP39. We have thus identified regions of VP39 important for interaction with its two substrates for cap-dependent methyltransferase activity: AdoMet and cap 0.