557 research outputs found
Interfacing single-atom catalysis with continuous-flow organic electrosynthesis
The global warming crisis has sparked a series of environmentally cautious trends in chemistry, allowing us to rethink the way we conduct our synthesis, and to incorporate more earth-abundant materials in our catalyst design. “Single-atom catalysis” has recently appeared on the catalytic spectrum, and has truly merged the benefits that homogeneous and heterogeneous analogues have to offer. Further still, the possibility to activate these catalysts by means of a suitable electric potential could pave the way for a true integration of diverse synthetic methodologies and renewable electricity. Despite their esteemed benefits, single-atom electrocatalysts are still limited to the energy sector (hydrogen evolution reaction, oxygen reduction, etc.) and numerous examples in the literature still invoke the use of precious metals (Pd, Pt, Ir, etc.). Additionally, batch electroreactors are employed, which limit the intensification of such processes. It is of paramount importance that the field continues to grow in a more sustainable direction, seeking new ventures into the space of organic electrosynthesis and flow electroreactor technologies. In this piece, we discuss some of the progress being made with earth abundant homogeneous and heterogeneous electrocatalysts and flow electrochemistry, within the context of organic electrosynthesis, and highlight the prospects of alternatively utilizing single-atom catalysts for such applications
Risk of malignant lymphoma associated with human herpesvirus-8: a case–control study in Spain
No overall increased risk of lymphoma associated with antibodies to human herpesvirus-8 was found in 526 lymphomas and 599 controls (odds ratio (OR)=1.04, 95% confidence interval (CI)=0.62-1.75); significant increases were noted for 19 lymphoplasmacytic lymphomas (OR=4.47, 95% CI=1.34-14.85) and nine low-grade lymphoma/lymphoma B-cell NOS (OR=5.82, 95% CI=1.07-31.73)
Early age at first sexual intercourse and early pregnancy are risk factors for cervical cancer in developing countries
Early age at first sexual intercourse (AFSI) has long been associated with an increased risk of invasive cervical carcinoma (ICC). Age at first pregnancy (AFP) and ICC have been investigated less, although AFSI and AFP are strongly interrelated in most developing countries. A pooled analysis of case–control studies on ICC from eight developing countries with 1864 cases and 1719 controls investigated the roles of AFSI, AFP, and ICC risk. Age at first sexual intercourse, AFP and age at first marriage (AFM) were highly interrelated and had similar ICC risk estimates. Compared with women with AFSI ⩾21 years, the odds ratio (OR) of ICC was 1.80 (95% CI: 1.50–2.39) among women with AFSI 17–20 years and 2.31 (95% CI: 1.85–2.87) for AFSI ⩽16 years (P-trend <0.001). No statistical interaction was detected between AFSI and any established risk factors for ICC. The ICC risk was 2.4-fold among those who reported AFSI and AFP at ⩽16 years compared with those with AFSI and AFP at ⩾21 years. These data confirm AFSI and AFB as risk factors for ICC in eight developing countries, but any independent effects of these two events could not be distinguished
SP-0489: HPV-transformation in the cervix and at non-cervical sites
Pla general d'un dels panells horitzontals sobre espais verds de Barcelona a l'exposiciĂł Ciutat. Barcelona projecta a l'Edifici Fòrum. ExposiciĂł sobre la planificaciĂł urbanĂstica i arquitectònica de Barcelon
White light emission from lead-free mixed-cation doped Cs2SnCl6 nanocrystals
We have designed a synthesis procedure to obtain Cs2SnCl6 nanocrystals (NCs) doped with metal ion(s) to emit visible light. Cs2SnCl6 NCs doped with Bi3+, Te4+ and Sb3+ ions emitted blue, yellow and red light, respectively. In addition, NCs simultaneously doped with Bi3+ and Te4+ ions were synthesized in a single run. Combination of both dopant ions together gives rise to the white emission. The photoluminescence quantum yields of the blue, yellow and white emissions are up to 26.5, 28, and 16.6%, respectively under excitation at 350, 390, and 370 nm. Pure white-light emission with CIE chromaticity coordinates of (0.32, 0.33) and (0.32, 0.32) at 340 and 370 nm excitation wavelength, respectively, was obtained. The as-prepared NCs were found to demonstrate a long-time stability, resistance to humidity, and an ability to be well-dispersed in polar solvents without property degradation due to their hydrophilicity, which could be of significant interest for wide application purposes
Chiral Symmetry and the Nucleon Structure Functions
The isospin asymmetry of the sea quark distribution as well as the
unexpectedly small quark spin fraction of the nucleon are two outstanding
discoveries recently made in the physics of deep-inelastic structure functions.
We evaluate here the corresponding quark distribution functions within the
framework of the chiral quark soliton model, which is an effective quark model
of baryons maximally incorporating the most important feature of low energy
QCD, i.e. the chiral symmetry and its spontaneous breakdown. It is shown that
the model can explain qualitative features of the above-mentioned nucleon
structure functions within a single framework, thereby disclosing the
importance of chiral symmetry in the physics of high energy deep-inelastic
scatterings.Comment: 20pages, LaTex, 5 Postscript figures A numerical error of the
original version was corrected. The discussion on the regularization
dependence of distribution functions has been added. A comparison with the
low energy-scale parametrization of Gloeck, Reya and Vogt has been mad
Single nucleotide polymorphisms of matrix metalloproteinase 9 (MMP9) and tumor protein 73 (TP73) interact with Epstein-Barr virus in chronic lymphocytic leukemia: results from the European case-control study EpiLymph
Using EpiLymph case-control data, we found that chronic lymphocytic leukemia patients were more likely to have abnormal reactive serological patterns to Epstein Barr virus than controls. Here, we aimed to assess whether this association is modified by genetic variants. We examined 1,305 Single Nucleotide Polymorphisms from 300 selected genes related to various pathways in 240 cases and 513 controls from five European centers. In a recessive model, patients positive to aberrant antibody pattern and homozygous for rare genotypes in rs8113877T>G or rs17576A>G of the MMP9 gene were at highest risk of chronic lymphocytic leukemia. In a dominant model, TP73 showed the highest risk in patients positive to aberrant antibody pattern and homozygous for the wild-type genotype in rs1885859G>C or rs3765701A>T. All interactions were additive and no main effect was observed. The strong interactions observed may be indicative of a specific pathway in cancer genesis. Confirmation of these results is warranted
Charge Symmetry Breaking in the Valence Quark Distributions of the Nucleon
Using a quark model, we study the effect of charge symmetry breaking on the
valence quark distributions of the nucleon. The effect due to quark mass
differences and the Coulomb interaction of the electrically charged quarks is
calculated and, in contrast to recent claims, found to be small. In addition,
we investigate the effect of charge symmetry breaking in the confining
interaction, and in the perturbative evolution equations used to relate the
quark model distributions to experiment. We find that both these effects are
small, and that the strong charge symmetry breaking effect included in the
scalar confining interactions may be distinguishable from that generated by
quark mass differences.Comment: 10 pages, LaTEX, 5 Postscript figure
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