Hybrid 3D structures of ZnO nanoflowers and PdO nanoparticles as a highly selective methanol sensor.

The present study concerns the enhancement of methanol selectivity of three dimensional (3D) nanoflowers (NFs) of ZnO by dispersing nickel oxide (NiO) and palladium oxide (PdO) nanoparticles on the surface of the nanoflowers to form localized hybrid nano-junctions. The nanoflowers were fabricated through a liquid phase deposition technique and the modification was achieved by addition of NiCl and PdCl2 solutions. In addition to the detailed structural (like X-ray diffraction (XRD), electron dispersive spectroscopy (EDS), X-ray mapping, XPS) and morphological characterization (by field emission scanning electron microscopy (FESEM)), the existence of different defect states (viz. oxygen vacancy) was also confirmed by photoluminescence (PL) spectroscopy. The sensing properties of the pristine and metal oxide nanoparticle (NiO/PdO)-ZnO NF hybrid sensor structures, towards different alcohol vapors (methanol, ethanol, 2-propanol) were investigated in the concentration range of 0.5-700 ppm at 100-350 °C. Methanol selectivity study against other interfering species, viz. ethanol, 2-propanol, acetone, benzene, xylene and toluene was also investigated. It was found that the PdO-ZnO NF hybrid system offered enhanced selectivity towards methanol at low temperature (150 °C) compared to the NiO-ZnO NF and pristine ZnO NF counterparts. The underlying mechanism for such improvement has been discussed with respective energy band diagram and preferential dissociation of target species on such 3D hybrid structures. The corresponding improvement in transient characteristics has also been co-related with the proposed model.

FoxO mediates APP-induced AICD-dependent cell death.

The amyloid precursor protein (APP) is a broadly expressed transmembrane protein that has a significant role in the pathogenesis of Alzheimer's disease (AD). APP can be cleaved at multiple sites to generate a series of fragments including the amyloid ß (Aß) peptides and APP intracellular domain (AICD). Although Aß peptides have been proposed to be the main cause of AD pathogenesis, the role of AICD has been underappreciated. Here we report that APP induces AICD-dependent cell death in Drosophila neuronal and non-neuronal tissues. Our genetic screen identified the transcription factor forkhead box O (FoxO) as a crucial downstream mediator of APP-induced cell death and locomotion defect. In mammalian cells, AICD physically interacts with FoxO in the cytoplasm, translocates with FoxO into the nucleus upon oxidative stress, and promotes FoxO-induced transcription of pro-apoptotic gene Bim. These data demonstrate that APP modulates FoxO-mediated cell death through AICD, which acts as a transcriptional co-activator of FoxO.

Atropine-sensitive hippocampal θ oscillations are mediated by Cav2.3 R-type Ca²âº channels.

Hippocampal theta oscillations are key elements in numerous behavioral and cognitive processes. Based on the dualistic theory of theta oscillations, one can differentiate between atropine-sensitive and atropine-insensitive theta subtypes. Urethane-induced atropine-sensitive theta oscillations are driven by muscarinic signal transduction pathways through G protein q/11 alpha subunit (Gα(q/11)), phospholipase ß( ») (PLCß( »), inositol trisphosphate (InsP3), diacylglycerole (DAG), and protein kinase C (PKC). Recent findings illustrate that Ca(v)2.3 Ca²âº channels are important targets of muscarinic signaling in the hippocampus mediating plateau potential generation, epileptiform burst activity, and complex rhythm generation in the septohippocampal network. To investigate the physiological implications of Ca(v)2.3 Ca²âº channels in hippocampal theta oscillations we performed radiotelemetric intrahippocampal (cornu ammonis (CA1)) recordings in urethane (800 mg/kg, i.p.) and atropine (50 mg/kg, i.p.) treated Ca(v)2.3⁺/⁺ and Ca(v)2.3⁻/⁻ mice followed by wavelet analysis of EEG data. Our results demonstrate that Ca(v)2.3 ablation, unlike PLCß1 deletion, does not result in complete abolishment of urethane-induced theta oscillations and that both mean and total theta duration is not significantly inhibited by subsequent atropine treatment, indicating that Ca(v)2.3 Ca²âº channels are important mediators of atropine-sensitive theta. Although theta frequency remained unchanged between both genotypes, the temporal characteristics of theta distribution, that is, theta architecture were significantly affected by the loss of Ca(v)2.3 Ca²âº channels. Our data suggest, for the first time, that Ca(v)2.3 voltage-gated Ca²âº channels (VGCC) are an important factor in septohippocampal synchronization associated with theta oscillation.

Taiwan's traffic control bundle and the elimination of nosocomial severe acute respiratory syndrome among healthcare workers.

The traffic control bundle consists of procedures designed to help prevent epidemic nosocomial infection. We retrospectively studied the serial infection control measures to determine factors most effective in preventing nosocomial infections of healthcare workers (HCWs) during the 2003 Taiwanese severe acute respiratory syndrome (SARS) epidemic. Fever screening stations, triage of fever patients, separating SARS patients from other patients, separation of entrances and passageways between patients and HCWs, and increasing hand-washing facilities all demonstrated a protective effect for HCWs (univariate analysis; P<0.05). By multiple logistic regression: (i) checkpoint alcohol dispensers for glove-on hand rubbing between zones of risk, and (ii) fever screening at the fever screen station outside the emergency department, were the significant methods effectively minimising nosocomial SARS infection of HCWs (P<0.05). The traffic control bundle should be implemented in future epidemics as a tool to achieve strict infection control measures.

Hypopigmented macular amyloidosis with or without hyperpigmentation.

Primary cutaneous amyloidosis (PCA) is a chronic pruritic skin disorder with characteristic amyloid deposits in the papillary dermis. We report three cases of PCA, which shared common features of hypopigmentation as a predominant feature with or without reticular hyperpigmentation, no itching, adult onset and dermal papillary amyloid deposition. These cases did not conform to the usual features of PCA.

Prevalence and molecular characteristics of Staphylococcus aureus isolates colonizing patients with atopic dermatitis and their close contacts in Singapore.

BACKGROUND: Staphylococcus aureus colonization is an established pathogenic factor for disease flare in atopic dermatitis (AD). OBJECTIVES: We conducted a study to investigate the colonization of S. aureus in patients with AD and their close contacts in order to evaluate the possibility of intrafamilial transmission. We sought to determine the distribution of the bacterial virulence factors and their correlation with disease severity. METHODS: Nasal swabs and skin swabs (patients with AD only) were taken from patients with AD aged 2-21 years and their close contacts, seen at the National Skin Centre from January to March 2007. All S. aureus isolates were typed using multilocus variable-number tandem-repeat fingerprinting (MLVF) and screened for virulence factors via polymerase chain reaction (PCR) analysis. AD severity was determined by the SCORAD index. RESULTS: A total of 34 patients with AD and 55 close contacts were recruited. Thirty-one (91%) patients were colonized with S. aureus. Twenty-five (45%) of their close contacts were also colonized, and MLVF showed a high concordance of S. aureus isolates in index patients and their close contacts. On multivariate analysis, patients with a moderate SCORAD were more likely to be colonized by enterotoxin B-positive S. aureus (P = 0.027). No virulence factor was significantly associated with a severe SCORAD. CONCLUSIONS: The prevalence of S. aureus colonization was high among patients with AD and their close contacts. However, no predominant isolate of S. aureus was found to be associated with AD. The presence of superantigen B is possibly associated with moderate rather than severe disease in our population.

The utility F-box for protein destruction.

A signature feature of all living organisms is their utilization of proteins to construct molecular machineries that undertake the complex network of cellular activities. The abundance of a protein element is temporally and spatially regulated in two opposing aspects: de novo synthesis to manufacture the required amount of the protein, and destruction of the protein when it is in excess or no longer needed. One major route of protein destruction is coordinated by a set of conserved molecules, the F-box proteins, which promote ubiquitination in the ubiquitin-proteasome pathway. Here we discuss the functions of F-box proteins in several cellular scenarios including cell cycle progression, synapse formation, plant hormone responses, and the circadian clock. We particularly emphasize the mechanisms whereby F-box proteins recruit specific substrates and regulate their abundance in the context of SCF E3 ligases. For some exceptions, we also review how F-box proteins function through non-SCF mechanisms.

Acoustic parameters of snoring sound to compare natural snores with snores during 'steady-state' propofol sedation.

OBJECTIVES: To investigate the acoustic similarity between natural and sedation-induced snores. DESIGN: Prospective observational study. SETTING: University Hospital Aintree, Liverpool, UK. PARTICIPANTS: Twenty-one patients, who had already had overnight snore recordings, completed a pre-operative sleep nasendoscopic examination. Endoscopic examination of the upper aero-digestive tract was performed at sequentially increasing, steady-state sedation levels, using intravenous propofol administered according to a weight/time-based algorithm to predict blood and effect site (tissue) concentrations. At each sedation level at which snoring occurred, snoring sound was recorded. From these samples, snore files, comprising the inspiratory sound of each snore were created. Similarly, from natural snores recorded pre-operatively, snore files, comprising the inspiratory sounds of the first 100 snores with the patient sleeping in a supine position, were also created. MAIN OUTCOME MEASURES: Snore duration (s), loudness (dBA), periodicity (%) and energy ratios for the frequency sub-bands 0-200, 0-250 and 0-400 Hz. RESULTS: Snore loudness increased significantly (P < 0.0001), whilst energy ratios for frequency bands 0-200, 0-250 and 0-400 Hz all decreased significantly as sedation level increased (P < 0.001). A significant difference between natural snoring and snoring induced at the lowest sedation level was shown (P < 0.0001). Endoscopic examination was not tolerated at this sedation level. CONCLUSIONS: The acoustic characteristics of sedation-induced and natural snores are sufficiently different to recommend the need for further research to determine whether the technique of sleep nasendoscopy is, in fact, a valid predictor of outcome of snoring surgery.

Using an integrated infection control strategy during outbreak control to minimize nosocomial infection of severe acute respiratory syndrome among healthcare workers.

Healthcare workers (HCWs) are at risk of acquiring severe acute respiratory syndrome (SARS) while caring for SARS patients. Personal protective equipment and negative pressure isolation rooms (NPIRs) have not been completely successful in protecting HCWs. We introduced an innovative, integrated infection control strategy involving triaging patients using barriers, zones of risk, and extensive installation of alcohol dispensers for glove-on hand rubbing. This integrated infection control approach was implemented at a SARS designated hospital ('study hospital') where NPIRs were not available. The number of HCWs who contracted SARS in the study hospital was compared with the number of HCWs who contracted SARS in 86 Taiwan hospitals that did not use the integrated infection control strategy. Two HCWs contracted SARS in the study hospital (0.03 cases/bed) compared with 93 HCWs in the other hospitals (0.13 cases/bed) during the same three-week period. Our strategy appeared to be effective in reducing the incidence of HCWs contracting SARS. The advantages included rapid implementation without NPIRs, flexibility to transfer patients, and re-inforcement for HCWs to comply with infection control procedures, especially handwashing. The efficacy and low cost are major advantages, especially in countries with large populations at risk and fewer economic resources.

Acoustic analysis of snoring before and after palatal surgery.

To investigate the effectiveness of palatal surgery for nonapnoeic snoring, 35 patients were block randomised to undergo one of two different palatoplasty procedures. Patients were admitted pre-operatively for audio recording of snoring sound and video recording of sleeping position, and between 1.0 and 4.1 months (mean 2.5) and between 5.9 and 17.5 months (mean 9.7) post-operatively. Sound files, comprising the inspiratory sound of the first 100 snores whilst sleeping in a supine position, were analysed using specifically designed software. Snore duration (s), loudness (dBA), periodicity (%) and energy ratios for the frequency bands 0-200 Hz, 0-250 Hz and 0-400 Hz were calculated. Subjective outcomes were noted. Operation type, body mass index, age, peak nasal inspiratory flow rate, Epworth sleep score and alcohol intake were considered as confounding variables. No patient was cured from snoring. Paired t-test analysis demonstrated statistically significant changes between pre- and early post-operative recordings for snore periodicity and energy ratios in the frequency ranges 0-200 Hz, 0-250 Hz and 0-400 Hz. In conclusion, only the 0-250-Hz energy ratio measurements maintained a statistically significant improvement at the time of the late post-operative recording, despite an obvious drift back to pre-operative levels. No confounding variables were identified. The subjective and objective results correlated poorly. Post-operative changes in the acoustic parameters of snoring sound, following palatal surgery, are demonstrable but short-lived.

Simple and rapid detection of Photobacterium damselae ssp. piscicida by a PCR technique and plating method.

AIMS: To detect Photobacterium damselae ssp. piscicida using the PCR technique and plating method. METHODS AND RESULTS: Two strains of P. damselae ssp. piscicida were isolated from cultured cobia (Rachycentron canadum) at two different fish farms in Taiwan. A pair of primers was designed to detect the capsular polysaccharide gene of P. damselae ssp. piscicida by PCR. Reference strains of different genus and different clinical strains were used for this study. The expected product (410 bp) was obtained from both P. damselae ssp. piscicida and P. damselae ssp. damselae, and they were differentiated by culturing on thiosulphate citrate bile salts-sucrose agar (TCBS-1). Photobacterium damselae ssp. damselae grew on TCBS-1 producing green colonies whereas P. damselae ssp. piscicida did not grow. CONCLUSIONS: The methods used are cost and labour effective when compared with the other methods and commercially available kits. SIGNIFICANCE AND IMPACT OF THE STUDY: This work provides an integrated set of methods to identify the species P. damselae and to differentiate P. damselae ssp. piscicida from P. damselae ssp. damselae.

Serum insulin-like growth factor-II and alpha-fetoprotein as tumor markers of hepatocellular carcinoma.

To evaluate the diagnostic application of serum insulin-like growth factor-II (IGF-II) and alpha-fetoprotein (AFP) levels in hepatocellular carcinoma (HCC), IGF-II and AFP were determined in 100 cirrhotic patients with HCC, 100 sex- and age-matched patients with cirrhosis alone and 50 healthy controls. The results indicated that IGF-II and AFP levels in patients with HCC were higher than in those with cirrhosis alone (p = 0.0001). There is an inverse correlation between IGF-II and (log)AFP (r = -0.410, p = 0.0001) in patients with HCC. Multivariate analysis indicated that IGF-II and AFP were closely associated, in a dose-related fashion, with the presence of HCC. Receiver operating characteristic curves were used to determine the optimal cutoff values of IGF-II (4.5 mg/g prealbumin) and AFP (100 ng/ml), respectively. Both IGF-II and AFP show a high specificity and positive likelihood ratio. The sensitivity was 42.0% for IGF-II and 73.0% for AFP. Determination of both markers in parallel significantly increased the diagnostic accuracy (96.5%) and sensitivity (97.9%), with a high specificity (95.1%) and positive likelihood ratio (19.9). In conclusion, IGF-II and AFP may be used as complementary tumor markers to discriminate HCC from cirrhosis.

Protection against lethal enterovirus 71 infection in newborn mice by passive immunization with subunit VP1 vaccines and inactivated virus.

Enterovirus 71 (EV71), the newest member of Enteroviridae, is notable for its etiological role in epidemics of severe neurological diseases in children. Developing effective vaccines is considered a top choice among all control measures. We compared the inactivated virus vaccine (10 microg protein/mouse) with subunit vaccines--VP1 DNA vaccine (100 microg/mouse) or recombinant VP1 protein (10 microg/mouse)--in its ability to elicit maternal antibody and to provide protection against lethal infection of EV71 in suckling mice. Prior to gestation, all three groups of vaccinated dams possessed similar levels of neutralizing antibody. With a challenge dose of 2300 LD(50) virus/mouse, suckling mice born to dams immunized with inactivated virus showed 80% survival. The subunit vaccines provided protection only at a lower challenge dosage of 230 LD(50) per mouse, with 40% survival for DNA vaccine and 80% survival for VP1 protein. The cytokine profile produced by splenocytes showed a high level of IL-4 in the inactivated virus group, high levels of IFN-gamma and IL-12 in the DNA vaccine group, and high levels of IL-10 and IFN-gamma in the VP1 protein group. Overall, the inactivated virus elicited a much greater magnitude of immune response than the subunit vaccines, including total IgG, all four IgG subtypes, and T-helper-cell responses; these antibodies were shown to be protective against lethal infection when passively transferred to susceptible newborn mice. Our data indicated that inactivated virus is the choice of vaccine preparation capable of fulfilling the demand for effective control, and that VP1 subunit vaccines remain promising vaccine strategies that require further refinement.

Betel quid chewing as a risk factor for hepatocellular carcinoma: a case-control study.

The role of betel quid chewing in the aetiology of hepatocellular carcinoma (HCC) was evaluated in a case-control study including 263 pairs of age- and sex-matched HCC patients and healthy controls. Serum hepatitis B surface antigen (HBsAg), and antibodies to hepatitis C virus (anti-HCV) were determined, and standardized personal interview conducted using a structured questionnaire. Multivariate analysis indicated that betel quid chewing (odds ratio (OR), 3.49; 95% confidence interval (CI), 1.74-6.96), HBsAg (OR, 16.69; 95% CI, 9.92-28.07), anti-HCV (OR, 38.57; 95% CI, 18.15-81.96), and educational duration of less than 10 years (OR, 1.71; 95% CI, 1.05-2.78) are independent risk factors of HCC. In addition, there was an additive interaction between betel quid chewing and chronic infection with either hepatitis B virus (synergy index, 5.37) or hepatitis C virus (synergy index, 1.66). Moreover, risk on HCC increased as duration of betel quid chewing increased, or amount of betel quid consumed (each P for trend < 0.0001).

Aberrant signal peptide cleavage of collagen X in Schmid metaphyseal chondrodysplasia. Implications for the molecular basis of the disease.

Schmid metaphyseal chondrodysplasia results from mutations in the collagen X (COL10A1) gene. With the exception of two cases, the known mutations are clustered in the C-terminal nonhelical (NC1) domain of the collagen X. In vitro and cell culture studies have shown that the NC1 mutations result in impaired collagen X trimer assembly and secretion. In the two other cases, missense mutations that alter Gly(18) at the -1 position of the putative signal peptide cleavage site were identified (Ikegawa, S., Nakamura, K., Nagano, A., Haga, N., and Nakamura, Y. (1997) Hum. Mutat. 9, 131-135). To study their impact on collagen X biosynthesis using in vitro cell-free translation in the presence of microsomes, and cell transfection assays, these two mutations were created in COL10A1 by site-directed mutagenesis. The data suggest that translocation of the mutant pre-alpha1(X) chains into the microsomes is not affected, but cleavage of the signal peptide is inhibited, and the mutant chains remain anchored to the membrane of microsomes. Cell-free translation and transfection studies in cells showed that the mutant chains associate into trimers but cannot form a triple helix. The combined effect of both the lack of signal peptide cleavage and helical configuration is impaired secretion. Thus, despite the different nature of the NC1 and signal peptide mutations in collagen X, both result in impaired collagen X secretion, probably followed by intracellular retention and degradation of mutant chains, and causing the Schmid metaphyseal chondrodysplasia phenotype.

Sex differences in relation to serum hepatitis B e antigen and alanine aminotransferase levels among asymptomatic hepatitis B surface antigen carriers.

This study aimed to investigate sex differences in relation to hepatitis B e antigen (HBeAg) and serum alanine aminotransferase (ALT) levels in chronic asymptomatic hepatitis B virus (HBV) infection. HBeAg and ALT level were determined in 636 asymptomatic hepatitis B surface antigen carriers. There was no significant sex differences in the age-adjusted prevalence of HBeAg. Abnormal ALT level (>45 IU/l) was more frequent in carriers with HBeAg (17.5% vs 7.6%; P = 0.001). Multivariate analysis indicated that male sex (odds ratio, 2.0; 95% confidence interval, 1.1-3.6) and HBeAg (odds ratio, 2.6; 95% confidence interval, 1.6-4.3) were independent risk factors for abnormal ALT levels. Male sex and HBeAg-positivity are independent risk factors for abnormal ALT activity in chronic HBV infection. This observation may be related to sex differences in chronic HBV infection.

Direct observation of electromigration of Si magic clusters on Si(111) surfaces.

Using scanning tunneling microscopy, we have observed electromigration of Si on Si(111)-(7x7) surfaces and have identified the diffusion species to be Si magic clusters. Effects of the directed motion along the direction of the heating current in electromigration and those in thermal migration are determined separately and quantitatively. We also observe the preferential filling of two-dimensional (2D) Si craters and the preferential detachment of Si magic clusters from the edges of 2D Si islands near the cathode side. The driving force for this anisotropic behavior is much stronger than previously recognized.