5,252 research outputs found
Laser-Photoacoustic Detection of Water Pollutants
We have investigated the potential of amplitude-modulation laser-photoacoustic scheme for the detection of trace pollutants in water. The technique has been found to be non-disturbing and easy-to-apply. In particular, the technique could be used to detect pollutants with a concentration corresponding to an absorption coefficient of 10-6cm-1. The sensitivity was found to be limited by a background signal resulting from light absorption by water. In addition to the amplitude-modulation scheme we also investigated the potential of a wavelength modulation scheme. Although this approach did reduce the background signal due to water absorption, we found the technique to be much more difficult to apply in practice
Phylogeny and biogeography of the Canarian Solanum vespertilio and S. lidii (Solanaceae)
Journal ArticleThe endemic and rare Solanum vespertilio and S. lidii from the Canary Islands are notable in being andromonoecious, self compatible, highly heterandrous (with short >reward= anthers and one very long >pollination= anther), and bearing strongly zygomorphic corollas. Solanum vespertilio flowers are also tetramerous, and some display enantiostyly
Synthesis and Characterization of Three-Coordinate Ni(III)-Imide Complexes
A new family of low-coordinate nickel imides supported by 1,2-bis(di-tert-butylphosphino)ethane was synthesized. Oxidation of nickel(II) complexes led to the formation of both aryl- and alkyl-substituted nickel(III)-imides, and examples of both types have been isolated and fully characterized. The aryl substituent that proved most useful in stabilizing the Ni(III)-imide moiety was the bulky 2,6-dimesitylphenyl. The two Ni(III)-imide compounds showed different variable-temperature magnetic properties but analogous EPR spectra at low temperatures. To account for this discrepancy, a low-spin/high-spin equilibrium was proposed to take place for the alkyl-substituted Ni(III)-imide complex. This proposal was supported by DFT calculations. DFT calculations also indicated that the unpaired electron is mostly localized on the imide nitrogen for the Ni(III) complexes. The results of reactions carried out in the presence of hydrogen donors supported the findings from DFT calculations that the adamantyl substituent was a significantly more reactive hydrogen-atom abstractor. Interestingly, the steric properties of the 2,6-dimesitylphenyl substituent are important not only in protecting the Ni═N core but also in favoring one rotamer of the resulting Ni(III)-imide, by locking the phenyl ring in a perpendicular orientation with respect to the NiPP plane
A pilot program at the worksite to reduce adverse self-medication behaviors
A Next Generation Personal Education Program (PEP-NG) that captures self-reported medication behaviors and delivers a tailored educational intervention on a touchscreen interface was piloted with 11 adults with hypertension, aged 45–60 years, in a worksite setting. A time series design with multiple institution of treatment (four visits over three months) was employed. Blood pressure (BP), self-medication behaviors, self-efficacy, and knowledge for avoiding adverse self-medication behaviors were assessed at each of four visits. Satisfaction was assessed once at visit 4. Measures pre-PEP (visit 1) to visit 4 were compared with paired t-tests. The adverse self-medication behavior risk score decreased significantly from visit 1 to visit 4 (p < 0.05) with a medium effect size. Both knowledge and self-efficacy for avoiding adverse self-medication behaviors increased significantly (p < 0.05) with large effect sizes. All six participants not at BP goal (<140/90 mmHg) on visit 1 were at goal by visit 4. User satisfaction was high as assessed by both quantitative measures and qualitative interviews. These positive results suggest the PEP could play a central role in worksite wellness programs aimed at workers with hypertension
Pharmacological control of neutrophil-mediated inflammation: Strategies targeting calcium handling by activated polymorphonuclear leukocytes
Unlike most other effector cells of the innate, as well as the adaptive immune systems, the neutrophil is a relatively undiscerning aggressor with scant regard for damage limitation. Although this highly combative, professional phagocyte has become increasingly implicated in the immunopathogenesis of many acute and chronic inflammatory disorders, of both infective and noninfective origin, effective pharmacological strategies to counter neutrophilaggression have remained elusive. Activation of neutrophils results in rapid mobilization of both stored and extracellular Ca2+, resulting in abrupt, usually transient increases in cytosolic Ca2+, which precede, and are a prerequisite for activation of the Ca2+-dependent pro-inflammatory activities of these cells. Mobilization of Ca2+ by, and restoration of Ca2+ homeostasis to activated neutrophils are multistep processes which present a number of potential targets, some well recognized and others noveland unconventional, for the pharmacological control of neutrophil-mediated inflammation. Uncovering these targets represents the primary focus of this review
Genome-Wide Mapping of Uncapped and Cleaved Transcripts Reveals a Role for the Nuclear mRNA Cap-Binding Complex in Cotranslational RNA Decay in Arabidopsis
RNA turnover is necessary for controlling proper mRNA levels posttranscriptionally. In general, RNA degradation is via exoribonucleases that degrade RNA either from the 5′ end to the 3′ end, such as XRN4, or in the opposite direction by the multisubunit exosome complex. Here, we use genome-wide mapping of uncapped and cleaved transcripts to reveal the global landscape of cotranslational mRNA decay in the Arabidopsis thaliana transcriptome. We found that this process leaves a clear three nucleotide periodicity in open reading frames. This pattern of cotranslational degradation is especially evident near the ends of open reading frames, where we observe accumulation of cleavage events focused 16 to 17 nucleotides upstream of the stop codon because of ribosomal pausing during translation termination. Following treatment of Arabidopsis plants with the translation inhibitor cycloheximide, cleavage events accumulate 13 to 14 nucleotides upstream of the start codon where initiating ribosomes have been stalled with these sequences in their P site. Further analysis in xrn4 mutant plants indicates that cotranslational RNA decay is XRN4 dependent. Additionally, studies in plants lacking CAP BINDING PROTEIN80/ABA HYPERSENSITIVE1, the largest subunit of the nuclear mRNA cap binding complex, reveal a role for this protein in cotranslational decay. In total, our results demonstrate the global prevalence and features of cotranslational RNA decay in a plant transcriptome
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