Ground-based intercomparison of two isoprene measurement techniques

International audienceAn informal intercomparison of two isoprene (C5H8) measurement techniques was carried out during Fall of 1998 at a field site located approximately 3 km west of Boulder, Colorado, USA. A new chemical ionization mass spectrometric technique (CIMS) was compared to a well-established gas chromatographic technique (GC). The CIMS technique utilized benzene cation chemistry to ionize isoprene. The isoprene levels measured by the CIMS were often larger than those obtained with the GC. The results indicate that the CIMS technique suffered from an anthropogenic interference associated with air masses from the Denver, CO metropolitan area as well as an additional interference occurring in clean conditions. However, the CIMS technique is also demonstrated to be sensitive and fast. Especially after introduction of a tandem mass spectrometric technique, it is therefore a candidate for isoprene measurements in remote environments near isoprene sources

The 9-methyl group of retinal is essential for rapid Meta II decay and phototransduction quenching in red cones

Cone photoreceptors of the vertebrate retina terminate their response to light much faster than rod photoreceptors. However, the molecular mechanisms underlying this rapid response termination in cones are poorly understood. The experiments presented here tested two related hypotheses: first, that the rapid decay rate of metarhodopsin (Meta) II in red-sensitive cones depends on interactions between the 9-methyl group of retinal and the opsin part of the pigment molecule, and second, that rapid Meta II decay is critical for rapid recovery from saturation of red-sensitive cones after exposure to bright light. Microspectrophotometric measurements of pigment photolysis, microfluorometric measurements of retinol production, and single-cell electrophysiological recordings of flash responses of salamander cones were performed to test these hypotheses. In all cases, cones were bleached and their visual pigment was regenerated with either 11-cis retinal or with 11-cis 9-demethyl retinal, an analogue of retinal lacking the 9-methyl group. Meta II decay was four to five times slower and subsequent retinol production was three to four times slower in red-sensitive cones lacking the 9-methyl group of retinal. This was accompanied by a significant slowing of the recovery from saturation in cones lacking the 9-methyl group after exposure to bright (>0.1% visual pigment photoactivated) but not dim light. A mathematical model of the turn-off process of phototransduction revealed that the slower recovery of photoresponse can be explained by slower Meta decay of 9-demethyl visual pigment. These results demonstrate that the 9-methyl group of retinal is required for steric chromophore–opsin interactions that favor both the rapid decay of Meta II and the rapid response recovery after exposure to bright light in red-sensitive cones

CD25-Treg-depleting antibodies preserving IL-2 signaling on effector T cells enhance effector activation and antitumor immunity.

Intratumoral regulatory T cell (Treg) abundance associates with diminished anti-tumor immunity and poor prognosis in human cancers. Recent work demonstrates that CD25, the high affinity receptor subunit for IL-2, is a selective target for Treg depletion in mouse and human malignancies; however, anti-human CD25 antibodies have failed to deliver clinical responses against solid tumors due to bystander IL-2 receptor signaling blockade on effector T cells, which limits their anti-tumor activity. Here we demonstrate potent single-agent activity of anti-CD25 antibodies optimized to deplete Tregs whilst preserving IL-2-STAT5 signaling on effector T cells, and demonstrate synergy with immune checkpoint blockade in vivo. Pre-clinical evaluation of an anti-human CD25 (RG6292) antibody with equivalent features demonstrates, in both non-human primates and humanized mouse models, efficient Treg depletion with no overt immune-related toxicities. Our data supports the clinical development of RG6292 and evaluation of novel combination therapies incorporating non-IL-2 blocking anti-CD25 antibodies in clinical studies

High Pressure Effects on Superconductivity

The review is devoted to a discussion of the effects of high pressure imposed on superconducting materials. Low-temperature superconductors, high-temperature superconducting cuprates, and some unconventional superconducting compounds are investigated. Experimental as well as theoretical results regarding the pressure effects on Tc and other interesting properties are summarized.Comment: To be published in: "Frontiers in Superconducting Materials", Edt. A. Narlikar, Springer Verla

Pleiotropy of genetic variants on obesity and smoking phenotypes: Results from the Oncoarray Project of The International Lung Cancer Consortium

Obesity and cigarette smoking are correlated through complex relationships. Common genetic causes may contribute to these correlations. In this study, we selected 241 loci potentially associated with body mass index (BMI) based on the Genetic Investigation of ANthropometric Traits (GIANT) consortium data and calculated a BMI genetic risk score (BMI-GRS) for 17,037 individuals of European descent from the Oncoarray Project of the International Lung Cancer Consortium (ILCCO). Smokers had a significantly higher BMI-GRS than never-smokers (p = 0.016 and 0.010 before and after adjustment for BMI, respectively). The BMI-GRS was also positively correlated with pack-years of smoking (p<0.001) in smokers. Based on causal network inference analyses, seven and five of 241 SNPs were classified to pleiotropic models for BMI/smoking status and BMI/pack-years, respectively. Among them, three and four SNPs associated with smoking status and pack-years (p<0.05), respectively, were followed up in the ever-smoking data of the Tobacco, Alcohol and Genetics (TAG) consortium. Among these seven candidate SNPs, one SNP (rs11030104, BDNF) achieved statistical significance after Bonferroni correction for multiple testing, and three suggestive SNPs (rs13021737, TMEM18; rs11583200, ELAVL4; and rs6990042, SGCZ) achieved a nominal statistical significance. Our results suggest that there is a common genetic component between BMI and smoking, and pleiotropy analysis can be useful to identify novel genetic loci of complex phenotypes