Mass Spectrometry-Based Label-Free Quantitative Proteomics

In order to study the differential protein expression in complex biological samples, strategies for rapid, highly reproducible and accurate quantification are necessary. Isotope labeling and fluorescent labeling techniques have been widely used in quantitative proteomics research. However, researchers are increasingly turning to label-free shotgun proteomics techniques for faster, cleaner, and simpler results. Mass spectrometry-based label-free quantitative proteomics falls into two general categories. In the first are the measurements of changes in chromatographic ion intensity such as peptide peak areas or peak heights. The second is based on the spectral counting of identified proteins. In this paper, we will discuss the technologies of these label-free quantitative methods, statistics, available computational software, and their applications in complex proteomics studies

Capital social, brechas digitales y transmisión intergeneracional del capital cultural en comunidades urbanas estadounidenses desfavorecidas: un estudio exploratorio

Advancing the classic network model of cultural capital, this study draws on social capital theories and digital divide and inclusion literature to examine the implications of social capital and digital connections for parents’ cultural capital in marginalized urban communities in two aspects: parents’ cultural knowledge and intergenerational cultural participation. Drawing on a household survey of an extremely disadvantaged population living in public housing communities in a major American city, results show that parents with greater social capital command greater cultural knowledge, which in turn can increase their intergenerational cultural participation. Parents’ social capital, however, has no direct impacts on intergenerational cultural participation. By contrast, the findings suggested that internet access alone is not enough for digital inclusion to increase cultural capital.Este estudio busca contribuir al modelo de red clásico del capital cultural, basándose en las teorías del capital social y la literatura sobre brecha digital e inclusión. Pretende examinar la influencia del capital social y las conexiones digitales en el capital cultural de los padres de comunidades urbanas marginadas en dos aspectos: el conocimiento cultural de estos y la participación cultural intergeneracional. A partir de una encuesta a hogares de una población de extremadamente desfavorecida, que vive en comunidades de viviendas públicas de una gran ciudad estadounidense, los resultados muestran que los padres con mayor capital social poseen mayor conocimiento cultural, que puede aumentar su participación cultural intergeneracional. Sin embargo, el capital social de estos no tiene efectos directos en la participación cultural intergeneracional. En cambio, los resultados sugieren que el acceso a Internet por sí solo no es suficiente para que la inclusión digital en las comunidades desfavorecidas aumente el capital cultural

Oriented Three-Dimensional Magnetic Biskyrmion in MnNiGa Bulk Crystals

A biskyrmion consists of two bound, topologically stable skyrmion spin textures. These coffee-bean-shaped objects have been observed in real-space in thin plates using Lorentz transmission electron microscopy (LTEM). From LTEM imaging alone, it is not clear whether biskyrmions are surface-confined objects, or, analogously to skyrmions in non-centrosymmetric helimagnets, three-dimensional tube-like structures in bulk sample. Here, we investigate the biskyrmion form factor in single- and polycrystalline MnNiGa samples using small angle neutron scattering (SANS). We find that biskyrmions are not long-range ordered, not even in single-crystals. Surprisingly all of the disordered biskyrmions have their in-plane symmetry axis aligned along certain directions, governed by the magnetocrystalline anisotropy. This anisotropic nature of biskyrmions may be further exploited to encode information

High-sensitive and rapid detection of Mycobacterium tuberculosis infection by IFN-γ release assay among HIV-infected individuals in BCG-vaccinated area

<p>Abstract</p> <p>Background</p> <p>An accurate test for <it>Mycobacterium tuberculosis </it>infection is urgently needed in immunosuppressed populations. The aim of this study was to investigate the diagnostic power of enzyme-linked immunospot (ELISPOT)-based IFN-γ release assay in detecting active and latent tuberculosis in HIV-infected population in <it>bacillus Calmette-Guerin </it>(BCG)-vaccinated area. A total of 100 HIV-infected individuals including 32 active tuberculosis patients were recruited. An ELISPOT-based IFN-γ release assay, T-SPOT.TB, was used to evaluate the <it>M. tuberculosis </it>ESAT-6 and CFP-10 specific IFN-γ response. Tuberculin skin test (TST) was performed for all recruited subjects.</p> <p>Results</p> <p>The subjects were divided into group HIV+ATB (HIV-infected individuals with active tuberculosis, n = 32), group HIV+LTB (HIV-infected individuals with positive results of T-SPOT.TB assay, n = 46) and group HIV only (HIV-infected individuals with negative results of T-SPOT.TB assay and without evidence of tuberculosis infection, n = 22). In group HIV+ATB and HIV+LTB, T-SPOT.TB positive rate in subjects with TST <5 mm were 50% (16/32) and 41.3% (19/46), respectively. Individuals in group HIV+ATB and HIV+LTB with CD4+ T cells <500/μl, T-SPOT.TB showed a higher sensitivity than TST (64.5% vs. 22.6% and 62.2% vs. 29.7%, respectively, both <it>P </it>< 0.0001). In addition, the sensitivity of T-SPOT.TB assay in group HIV+ATB increased to >85% in patients with TB treatment for less than 1 month and CD4+ T cells ≥200/μl, while for patients treated for more than 3 months and CD4+ T cells <200/μl, the sensitivity was decreased to only 33.3%. Furthermore, the results could be generated by T-SPOT.TB assay within 24 hours, which was more rapid than TST with 48–72 hours.</p> <p>Conclusion</p> <p>ELISPOT-based IFN-γ release assay is more sensitive and rapid for the diagnosis of TB infection in Chinese HIV-infected individuals with history of BCG vaccination, and could be an effective tool for guiding preventive treatment with isoniazid in latently infected people and for TB control in China.</p

Increased dry-season length over southern Amazonia in recent decades and its implication for future climate projection

RESUMEN: We have observed that the dry-season length (DSL) has increased over southern Amazonia since 1979, primarily owing to a delay of its ending dates (dry-season end, DSE), and is accompanied by a prolonged fire season. A poleward shift of the subtropical jet over South America and an increase of local convective inhibition energy in austral winter (June–August) seem to cause the delay of the DSE in austral spring (September–November). These changes cannot be simply linked to the variability of the tropical Pacific and Atlantic Oceans. Although they show some resemblance to the effects of anthropogenic forcings reported in the literature, we cannot attribute them to this cause because of inadequate representation of these processes in the global climate models that were presented in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. These models significantly underestimate the variability of the DSE and DSL and their controlling processes. Such biases imply that the future change of the DSE and DSL may be underestimated by the climate projections provided by the Intergovernmental Panel on Climate Change’s Fifth Assessment Report models. Although it is not clear whether the observed increase of the DSL will continue in the future, were it to continue at half the rate of that observed, the long DSL and fire season that contributed to the 2005 drought would become the new norm by the late 21st century. The large uncertainty shown in this study highlights the need for a focused effort to better understand and simulate these changes over southern Amazonia