288 research outputs found
Lambda and Antilambda polarization from deep inelastic muon scattering
We report results of the first measurements of Lambda and Antilambda
polarization produced in deep inelastic polarized muon scattering on the
nucleon. The results are consistent with an expected trend towards positive
polarization with increasing x_F. The polarizations of Lambda and Antilambda
appear to have opposite signs. A large negative polarization for Lambda at low
positive x_F is observed and is not explained by existing models.A possible
interpretation is presented.Comment: 9 pages, 2 figure
Increasingly strong reduction in breast cancer mortality due to screening
Item does not contain fulltextBACKGROUND: Favourable outcomes of breast cancer screening trials in the 1970s and 1980s resulted in the launch of population-based service screening programmes in many Western countries. We investigated whether improvements in mammography and treatment modalities have had an influence on the effectiveness of breast cancer screening from 1975 to 2008. METHODS: In Nijmegen, the Netherlands, 55,529 women received an invitation for screening between 1975 and 2008. We designed a case-referent study to evaluate the impact of mammographic screening on breast cancer mortality over time from 1975 to 2008. A total number of 282 breast cancer deaths were identified, and 1410 referents aged 50-69 were sampled from the population invited for screening. We estimated the effectiveness by calculating the odds ratio (OR) indicating the breast cancer death rate for screened vs unscreened women. RESULTS: The breast cancer death rate in the screened group over the complete period was 35% lower than in the unscreened group (OR=0.65; 95% CI=0.49-0.87). Analysis by calendar year showed an increasing effectiveness from a 28% reduction in breast cancer mortality in the period 1975-1991 (OR=0.72; 95% CI=0.47-1.09) to 65% in the period 1992-2008 (OR=0.35; 95% CI=0.19-0.64). CONCLUSION: Our results show an increasingly strong reduction in breast cancer mortality over time because of mammographic screening
Antigen-Displaying Lipid-Enveloped PLGA Nanoparticles as Delivery Agents for a Plasmodium vivax Malaria Vaccine
The parasite Plasmodium vivax is the most frequent cause of malaria outside of sub-Saharan Africa, but efforts to develop viable vaccines against P. vivax so far have been inadequate. We recently developed pathogen-mimicking polymeric vaccine nanoparticles composed of the FDA-approved biodegradable polymer poly(lactide-co-glycolide) acid (PLGA) “enveloped” by a lipid membrane. In this study, we sought to determine whether this vaccine delivery platform could be applied to enhance the immune response against P. vivax sporozoites. A candidate malaria antigen, VMP001, was conjugated to the lipid membrane of the particles, and an immunostimulatory molecule, monophosphoryl lipid A (MPLA), was incorporated into the lipid membranes, creating pathogen-mimicking nanoparticle vaccines (VMP001-NPs). Vaccination with VMP001-NPs promoted germinal center formation and elicited durable antigen-specific antibodies with significantly higher titers and more balanced Th1/Th2 responses in vivo, compared with vaccines composed of soluble protein mixed with MPLA. Antibodies raised by NP vaccinations also exhibited enhanced avidity and affinity toward the domains within the circumsporozoite protein implicated in protection and were able to agglutinate live P. vivax sporozoites. These results demonstrate that these VMP001-NPs are promising vaccines candidates that may elicit protective immunity against P. vivax sporozoites.United States. Dept. of Defense (contract W911NF-07-D-0004)Ragon Institute of MGH, MIT and Harvar
Comprehensive determination of 3JHNHα for unfolded proteins using 13C′-resolved spin-echo difference spectroscopy
An experiment is presented to determine 3JHNHα coupling constants, with significant advantages for applications to unfolded proteins. The determination of coupling constants for the peptide chain using 1D 1H, or 2D and 3D 1H-15N correlation spectroscopy is often hampered by extensive resonance overlap when dealing with flexible, disordered proteins. In the experiment detailed here, the overlap problem is largely circumvented by recording 1H-13C′ correlation spectra, which demonstrate superior resolution for unfolded proteins. J-coupling constants are extracted from the peak intensities in a pair of 2D spin-echo difference experiments, affording rapid acquisition of the coupling data. In an application to the cytoplasmic domain of human neuroligin-3 (hNlg3cyt) data were obtained for 78 residues, compared to 54 coupling constants obtained from a 3D HNHA experiment. The coupling constants suggest that hNlg3cyt is intrinsically disordered, with little propensity for structure
Uncovering the nutritional landscape of food
Recent progresses in data-driven analysis methods, including network-based
approaches, are revolutionizing many classical disciplines. These techniques
can also be applied to food and nutrition, which must be studied to design
healthy diets. Using nutritional information from over 1,000 raw foods, we
systematically evaluated the nutrient composition of each food in regards to
satisfying daily nutritional requirements. The nutrient balance of a food was
quantified herein as nutritional fitness, using the food's frequency of
occurrence in nutritionally adequate food combinations. Nutritional fitness
offers prioritization of recommendable foods within a global network of foods,
in which foods are connected based on the similarities of their nutrient
compositions. We identified a number of key nutrients, such as choline and
alpha-linolenic acid, whose levels in foods can critically affect the foods'
nutritional fitness. Analogously, pairs of nutrients can have the same effect.
In fact, two nutrients can impact the nutritional fitness synergistically,
although the individual nutrients alone may not. This result, involving the
tendency among nutrients to show correlations in their abundances across foods,
implies a hidden layer of complexity when exploring for foods whose balance of
nutrients within pairs holistically helps meet nutritional requirements.
Interestingly, foods with high nutritional fitness successfully maintain this
nutrient balance. This effect expands our scope to a diverse repertoire of
nutrient-nutrient correlations, integrated under a common network framework
that yields unexpected yet coherent associations between nutrients. Our
nutrient-profiling approach combined with a network-based analysis provides a
more unbiased, global view of the relationships between foods and nutrients,
and can be extended towards nutritional policies, food marketing, and
personalized nutrition.Comment: Supplementary material is available at the journal websit
Redundant Notch1 and Notch2 Signaling Is Necessary for IFNγ Secretion by T Helper 1 Cells During Infection with Leishmania major
The protective immune response to intracellular parasites involves in most cases the differentiation of IFNγ-secreting CD4+ T helper (Th) 1 cells. Notch receptors regulate cell differentiation during development but their implication in the polarization of peripheral CD4+ T helper 1 cells is not well understood. Of the four Notch receptors, only Notch1 (N1) and Notch2 (N2) are expressed on activated CD4+ T cells. To investigate the role of Notch in Th1 cell differentiation following parasite infection, mice with T cell-specific gene ablation of N1, N2 or both (N1N2ΔCD4Cre) were infected with the protozoan parasite Leishmania major. N1N2ΔCD4Cre mice, on the C57BL/6 L. major-resistant genetic background, developed unhealing lesions and uncontrolled parasitemia. Susceptibility correlated with impaired secretion of IFNγ by draining lymph node CD4+ T cells and increased secretion of the IL-5 and IL-13 Th2 cytokines. Mice with single inactivation of N1 or N2 in their T cells were resistant to infection and developed a protective Th1 immune response, showing that CD4+ T cell expression of N1 or N2 is redundant in driving Th1 differentiation. Furthermore, we show that Notch signaling is required for the secretion of IFNγ by Th1 cells. This effect is independent of CSL/RBP-Jκ, the major effector of Notch receptors, since L. major-infected mice with a RBP-Jκ deletion in their T cells were able to develop IFNγ-secreting Th1 cells, kill parasites and heal their lesions. Collectively, we demonstrate here a crucial role for RBP-Jκ-independent Notch signaling in the differentiation of a functional Th1 immune response following L. major infection
100% complete assignment of non-labile 1H, 13C, and 15N signals for calcium-loaded calbindin D9k P43G
Here we present the 100% complete assignment chemical shift of non-labile 1H, 15N and 13C nuclei of Calbindin D9k P43G. The assignment includes all non-exchangeable side chain nuclei, including ones that are rarely reported, such as LysNζ as well as the termini. NMR experiments required to achieve truly complete assignments are discussed. To the best of our knowledge our assignments for Calbindin D9k extend beyond previous studies reaching near-completeness (Vis et al. in Biochem 33:14858–14870, 1994; Yamazaki et al. in J Am Chem Soc 116:6464–6465, 1994; Yamazaki et al. in Biochem 32:5656–5669, 1993b)
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