Airborne measurements of ethene from industrial sources using laser photo-acoustic spectroscopy

A laser photoacoustic spectroscopy (LPAS) instrument was developed and used for aircraft measurements of ethene from industrial sources near Houston, Texas. The instrument provided 20 s measurements with a detection limit of less than 0.7 ppbv. Data from this instrument and from the GC-FID analysis of air samples collected in flight agreed within 15% on average. Ethene fluxes from the Mt. Belvieu chemical complex to the northeast of Houston were quantified during 10 different flights. The average flux was 520 +/- 140 kg h(-1) in agreement with independent results from solar occultation flux (SOF) measurements, and roughly an order of magnitude higher than regulatory emission inventories indicate. This study shows that ethene emissions are routinely at levels that qualify as emission upsets, which need to be reported to regional air quality managers.

Molecular characterisation of outbreak-related strains of vancomycin-resistant Enterococcus faecium from an intensive care unit in Beijing, China

We investigated an outbreak of vancomycin-resistant Enterococcus faecium affecting 14 patients in a 20-bed intensive care unit (ICU) between September 2006 and August 2007 (incidence: 3.56 cases per 1000 ICU patient days). Eighteen isolates of vanA type E. faecium were analysed by pulsed field gel electrophoresis, which showed 14 types overall. Multilocus sequence typing (MLST) identified eight different sequence types (STs) (ST78, ST117, ST203, ST316, ST362, ST363, ST364 and ST365), including four new types (ST362, ST363, ST364 and ST365) and 17 strains belonged to clonal complexes CC17. Sixteen of these carried the esp gene. Eighteen Tn1546-like elements encoding vanA-type VRE were classified into three types (types I to III) and all of them contained both IS1216V and IS1542 insertions. Vancomycin resistance of 14 vanA type E. faecium isolates was transferred at a frequency of 1.3 x 10(-6) to 6.4 x 10(-5) between E. faecium strains during filter mating. Our findings indicate that conjugative dissemination of Tn1546-like elements among CC17 E. faecium occurred during the outbreak in this ICU.

A genital tract peptide epitope vaccine targeting TLR-2 efficiently induces local and systemic CD8+ T cells and protects against herpes simplex virus type 2 challenge

The next generation of needle-free mucosal vaccines is being rationally designed according to rules that govern the way in which the epitopes are recognized by and stimulate the genital mucosal immune system. We hypothesized that synthetic peptide epitopes extended with an agonist of Toll-like receptor 2 (TLR-2), that are abundantly expressed by dendritic and epithelial cells of the vaginal mucosa, would lead to induction of protective immunity against genital herpes. To test this hypothesis, we intravaginally (IVAG) immunized wild-type B6, TLR-2 (TLR2(-/-)) or myeloid differentiation factor 88 deficient (MyD88(-/-)) mice with a herpes simplex virus type 2 (HSV-2) CD8+ T-cell peptide epitope extended by a palmitic acid moiety (a TLR-2 agonist). IVAG delivery of the lipopeptide generated HSV-2-specific memory CD8+ cytotoxic T cells both locally in the genital tract draining lymph nodes and systemically in the spleen. Moreover, lipopeptide-immunized TLR2(-/-) and MyD88(-/-) mice developed significantly less HSV-specific CD8+ T-cell response, earlier death, faster disease progression, and higher vaginal HSV-2 titers compared to lipopeptide-immunized wild-type B6 mice. IVAG immunization with self-adjuvanting lipid-tailed peptides appears to be a novel mucosal vaccine approach, which has attractive practical and immunological features.

Heat-stress-induced damage to porcine small intestinal epithelium associated with downregulation of epithelial growth factor signaling

Extreme heat during certain days of the summer renders pigs susceptible to severe heat stress, which negatively affects their growth performance. We hypothesized that such heat stress impaired the small intestinal mucosa, a site responsible for nutrient absorption. To simulate heat stress, Chinese experimental mini-pigs were treated with 5 h of continual 40 degrees C temperature each day for 10 d in succession. Pigs were killed at 1, 3, 6 and 10 d after treatment, and small intestinal epithelia were sampled for histochemical examination and biochemical analyses. The duodenum and jejunum were seriously damaged within 3 d of initiation of treatment. Subsequent study of the process of jejunum recovery showed that the initiation of recovery started within 6 d following heat stress. Such damage was associated with the downregulation of epithelial growth factor signaling. In conclusion, heat stress induced short-term damage to the epithelium of porcine intestine. Because the intestinal epithelium is crucial for nutrient uptake, such damage should partially account for the impairment of growth performance of pigs under heat stress.

Oxidative stress signaling in Alzheimer's disease

Multiple lines of evidence demonstrate that oxidative stress is an early event in Alzheimer's disease (AD), occurring prior to cytopathology, and therefore may play a key pathogenic role in AD. Oxidative stress not only temporally precedes the pathological lesions of the disease but also activates cell signaling pathways, which, in turn, contribute to lesion formation and, at the same time, provoke cellular responses such as compensatory upregulation of antioxidant enzymes found in vulnerable neurons in AD. In this review, we provide an overview of the evidence of oxidative stress and compensatory responses that occur in AD, particularly focused on potential sources of oxidative stress and the roles and mechanism of activation of stress-activated protein kinase pathways.

Pulse width effect in ultrafast laser ionization imaging

The effects of different laser pulse widths on laser-induced ionization imaging of microstructures embedded in transparent materials are investigated. It is shown that a femtosecond laser-induced ionization probe can detect the variation of elemental composition of the sample materials with a higher contrast ratio, whereas the ionization probe generated by picosecond laser pulses is more sensitive to the structural change inside optical materials, which can be well explained by the different roles of multiphoton ionization and avalanche ionization involved in material breakdown. These results also suggest that an optimum diagnosis could be obtained if well-selected laser parameters are employed in ultrafast laser ionization imaging.

Latent common genetic components of obesity traits

Background

Obesity is rapidly becoming a global epidemic. Unlike many complex human diseases, obesity is defined not just by a single trait or phenotype, but jointly by measures of anthropometry and metabolic status.

Methods

We applied maximum likelihood factor analysis to identify common latent factors underlying observed covariance in multiple obesity-related measures. Both the genetic components and the mode of inheritance of the common factors were evaluated. A total of 1775 participants from 590 families for whom measures on obesity-related traits were available were included in this study.

Results

The average age of participants was 37 years, 39% of the participants were obese (body mass index ≥ 30.0 kg/m²) and 26% were overweight (body mass index 25.0 - 29.9 kg/m²). Two latent common factors jointly accounting for over 99% of the correlations among obesity-related traits were identified. Complex segregation analysis of the age and sex-adjusted latent factors provide evidence for a Mendelian mode of inheritance of major genetic effect with heritability estimates of 40.4% and 47.5% for the first and second factors, respectively.

Conclusions

These findings provide a support for multivariate-based approach for investigating pleiotropic effects on obesity-related traits which can be applied in both genetic linkage and association mapping.

Detailed investigation of self-imaging in large-core multimode optical fibers for application in fiber lasers and amplifiers

Properties of the self-imaging effect based on multimode interference (MMI) in large-core passive optical fibers are investigated and analyzed in detail, with the purpose of using multimode active fibers for high power single-transverse-mode emission. Although perfect self-imaging of the input field from a standard single-mode fiber (SMF-28) in a multimode fiber becomes practically impossible as its core diameter is larger than 50 microm, a quasi-reproduction of the input field occurs when the phase difference between the excited modes and the peak mode inside the multimode fiber is very small. Our simulation and experimental results indicate that, if the length of the multimode fiber segment can be controlled accurately, reproduction of the input field with a self-imaging quality factor larger than 0.9 can be obtained. In this case, a low-loss hybrid fiber cavity composed of a SMF-28 segment and a very-large-core active multimode fiber segment can be built. It is also found that for the hybrid fiber cavity, increasing the mode-field diameter of the single-mode fiber improves both the self-imaging quality and the tolerance on the required length accuracy of the multimode fiber segment. Moreover, in this paper key parameters for the design of MMI-based fiber devices are defined and their corresponding values are provided for multimode fibers with core diameters of 50 microm and 105 microm.

Therapeutic effects on experimental metastatic tumor-bearing mice by vaccination with GM-CSF gene-modified and tumor antigen-pulsed macrophages

Macrophages, with potent cytotoxic and antigen-presenting activities, can be used in cancer treatment. The biological characteristics and antitumor effect of GM-CSF gene-modified and tumor antigen-pulsed macrophages were investigated. The high levels of GM-CSF could be detected in the supernatants of macrophages after gene transfer. The cytotoxicity and the expression of MHC class II molecules of the gene-modified macrophages increased significantly and the antigen-presenting ability was enhanced. The gene-modified macrophages were then pulsed with tumor antigen and used to treat the experimental pulmonary metastastic mice. The number of pulmonary metastases was reduced significantly and the cytotoxicity of the CTL induced from the splenocytes of the tumor-bearing mice also increased. The results demonstrated that adenovirus-mediated GM-CSF gene transfer can activate macrophages to some extent and GM-CSF gene-modified, antigen-pulsed macrophages may be a new type of effective effector cells in the immunogene therapy of cancer.

Using linkage analysis to identify quantitative trait loci for sleep apnea in relationship to body mass index

To understand the genetics of sleep apnea, we evaluated the relationship between the apnea hypopnea index (AHI) and body mass index (BMI) through linkage analysis to identify genetic loci that may influence AHI and BMI jointly and AHI independent of BMI. Haseman-Elston sibling regression was conducted on AHI, AHI adjusted for BMI and BMI in African-American and European-American pedigrees. A comparison of the magnitude of linkage peaks was used to assess the relationship between AHI and BMI. In EAs, the strongest evidence for linkage to AHI was on 6q23-25 and 10q24-q25, both decreasing after BMI adjustment, suggesting loci with pleiotropic effects. Also, a promising area of linkage to AHI but not BMI was observed on 6p11-q11 near the orexin-2 receptor, suggesting BMI independent pathways. In AAs the strongest evidence of linkage for AHI after adjusting for BMI was on chromosome 8p21.3 with linkage increasing after BMI adjustment and on 8q24.1 with linkage decreasing after BMI adjustment. Novel linkage peaks were also observed in AAs to both BMI and AHI on chromosome 13 near the serotonin-2a receptor. These analyses suggest genetic loci for sleep apnea that operate both independently of BMI and through BMI-related pathways.

Highly discordant T cell responses in individuals with recent exposure to household tuberculosis

BACKGROUND

There are limited data comparing interferon-gamma release assays (IGRAs) for the detection of Mycobacterium tuberculosis infection in highly endemic settings.

METHODS

A cross-sectional household contact study was conducted to measure the agreement of two IGRAs in relation to the tuberculin skin test (TST) to detect M tuberculosis infection and to assess the influence of M tuberculosis exposure and age.

RESULTS

In 82 individuals in household contact, 93% of children and 42% of adults had a high M tuberculosis contact score. The TST was positive in 78% of adults and 54% of children, the T-SPOT.TB was positive in 89% of children and 66% of adults and the QuantiFERON TB Gold (QTF) was positive in a similar proportion of adults and children (38.1% and 39.6%). In children there was poor agreement between the TST and T-SPOT.TB (kappa = -0.15) and the T-SPOT.TB and the QTF (kappa = -0.03), but good agreement between the TST and the QTF (kappa = 0.78) using 10 mm cut-off. In adults there was fair to moderate agreement between the TST and T-SPOT.TB (kappa = 0.38), the TST and QTF (kappa = 0.34) and T-SPOT.TB and QTF (kappa = -0.50). High levels of exposure to M tuberculosis were associated with at least a sevenfold odds of being T-SPOT.TB positive (95% CI 7.67 to 508.69) and a threefold odds of being QTF positive (95% CI 3.02 to 30.54). There was a significant difference in the magnitude of T-SPOT.TB early secretory antigenic target (ESAT)-6 and culture filtrate protein 10 kD (CFP-10) spot counts between adults and children.

CONCLUSIONS

The T-SPOT.TB may be more sensitive than the TST or QTF for detecting recent M tuberculosis infection in children. Differences between assays and the predictive utility of these findings for subsequent disease development should be prospectively assessed.