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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A triple cage olfactometer provided with insect traps was used for evaluating behavioral responses of Stomoxys calcitrans (L.) females to human skin and breath, CO2, and L-lactic acid analogs. After demonstrating there were no significant differences caused by cage location or time of day, 3 sets of 3 olfactometer tests were performed in a day, every 2 h beginning at 0900 hours. When a human hand was used as attractant, the attraction (expressed as percentage of trapped flies) increased as a function of the time; an inverted U-shaped relationship between attractancy and air speed was observed; and variation in fly density in the range 25-75 per cage did not affect the attraction response. When human breath was used as attractant the attraction increased linearly as a function of time and it was exhalation frequency dependent; when air flow was absent the highest response was observed; and 24- to 38-h-old flies were more attracted than younger and older. When CO2 was tested, activation and orientation and probing behavior were concentration dependent with flows ranging between 0.0001 and 0.038 liter s(-1), but attraction was not. No attraction was observed with 10, 100, or 1,000 microg of compounds related to L-lactic acid and several synthetic human odors and related compounds, although orientation was often observed.
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PMID:Evaluation of Stomoxys calcitrans (Diptera: Muscidae) behavioral response to human and related odors in a triple cage olfactometer with insect traps. 1553 69

Synthesis of emerald green fullerenes (EF) C60[C(CH3)(CO2Et)2]6 and C60[C(CH3)(CO2-t-Bu)2]6 was performed by using hexaanionic C60 intermediate (C60-6) as a reagent in one-pot reaction for attaching six alkyl ester addends on one C60 cage. These EF compounds exhibit intense optical absorption over 600-940 nm, the longest optical absorption of the C60 cage among many [60]fullerene derivatives synthesized.
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PMID:Intense near-infrared optical absorbing emerald green [60]fullerenes. 1563 31

A Fourier transform infrared investigation of the rates and energetics of conversion of ice nanocrystals within 3-D arrays to ether clathrate-hydrate (CH) particles at approximately 120 K is reported. After an induction period, apparently necessitated by relatively slow nucleation of the CH phase, the well-established shrinking-core model of particle-adsorbate reaction applies to these conversions in the presence of an abundance of adsorbed ether. This implies that the transport of the ether adsorbate through the product crust encasing a reacting particle core (a necessary aspect of a particle reaction mechanism) is the rate-controlling factor. Diffusion moves adsorbed reactant molecules to the reaction zone at the interface of the ice core with the product (CH) crust. The results indicate that ether hydrate formation rates near 120 K resemble rates for gas hydrates measured near 260 K, implying rates greater by many orders of magnitude for comparable temperatures. A surprising secondary enhancement of ether CH-formation rates by the simultaneous incorporation of simple small gas molecules (N2, CO2, CH4, CO, and N2O) has also been quantified in this study. The rapid CH formation at low temperatures is conjectured to derive from defect-facilitated transport of reactants to an interfacial reaction zone, with the defect populations enhanced through transient H bonding of guest-ether proton-acceptor groups with O-H groups of the hydrate cage walls.
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PMID:Rates and mechanisms of conversion of ice nanocrystals to ether clathrate hydrates: guest-molecule catalytic effects at approximately 120 k. 1645 Oct 23

Carbon-cluster anions, CN-, are very reactive toward SO2 (sticking probability of 0.012 +/- 0.005 for C27- at 25 degrees C), in contrast to their inertness toward other common atmospheric gases and pollutants. In flow reactor experiments at ambient temperature and near atmospheric pressure, primary adsorption of SO2 by the carbon cluster anions, N = 4-60, yields CNSO2- or CN-1S-. The inferred elimination of neutral CO2 is also detected as meta-stable decay in collision-induced dissociation. At higher temperatures, the reaction of SO2 with nascent carbon clusters yields CN-1SO- as well as undetected CO. The size-dependent initial reactivity reflects the previously established structural transitions (i.e., from chain to cyclic to cage structures). Such carbon clusters are formed in sooting flames and may act as nuclei for the formation of primary soot particles and serve as models for the local structural features of active soot particle sites for black-carbon soot. The facile generation of reactive carbon-sulfide and -sulfinate units may therefore have implications for understanding the health and environmental effects attributed to the coincidence of soot and SO2.
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PMID:Efficient low-temperature oxidation of carbon-cluster anions by SO2. 1683 61

Molecular Dynamics simulations have been carried out in NaX and NaY Faujasite systems to deepen understanding of the cation rearrangement during the CO2 adsorption process suggested by our recent diffusivity measurements. This study is a major contribution since the rearrangement of the cations in Faujasite, the most promising adsorbent for CO2 storage, can represent a significant breakthrough in understanding the adsorption and diffusion processes at the mircroscopic scale. For NaY, it has been shown that at low and intermediate loadings, SII cations can migrate toward the center of the supercage due to strong interactions with the adsorbates, followed by a hopping of SI'cation from the sodalite cage into the supercage to fill the vacant SII site. The SI cations are only displaced at a higher loading, leading to cation de-trapping out of the double six rings into the vacant SI' sites. For NaX, the SIII' cations which occupy the most accessible adsorption sites move significantly upon coordination to the carbon dioxide molecules. The SI' and SII cations remain consistently located in their initial sites whatever the loading. Indeed, the most probable migration mechanism involves SIII' cation displacements into nearby vacant SIII' sites.
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PMID:Molecular dynamics simulation of the cation motion upon adsorption of CO2 in Faujasite zeolite systems. 1685 44

A new method of detecting the presence of deprotonation and determining its position in gas-phase polypeptide cations is described. The method involves 157-nm ultra-violet photodissociation (UVPD) and is based on monitoring the losses of CO2 (44 Da) from electronically excited deprotonated carboxylic groups relative to competing COOH losses (45 Da) from neutral carboxylic groups. Loss of CO2 is a strong indication of the presence of a zwitterionic [(+)...(-)...(+)] salt bridge in the gas-phase polypeptide cation. This method provides a tool for studying, for example, the nature of binding within polypeptide clusters. Collision-activated dissociation (CAD) of decarboxylated cations localizes the position of deprotonation. Fragment abundances can be used for the semiquantitative assessment of the branching ratio of deprotonation among different acidic sites, however, the mechanism of the fragment formation should be taken into account. Cations of Trp-cage proteins exist preferentially as zwitterions, with the deprotonation position divided between the Asp9 residue and the C terminus in the ratio 3:2. The majority of dications of the same molecule are not zwitterions. Furthermore, 157-nm UVPD produces abundant radical cations M*+ from protonated molecules through the loss of a hydrogen atom. This method of producing M*+ ions is general and can be applied to any gas-phase peptide cation. The abundance of the molecular radical cations M*+ produced is sufficient for further tandem mass spectrometry (MS/MS), which, in the cases studied, yielded side-chain loss of a basic amino acid as the most abundant fragmentation channel together with some backbone cleavages.
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PMID:Zwitterionic states in gas-phase polypeptide ions revealed by 157-nm ultra-violet photodissociation. 1687 5

Large amounts of CH4 in the form of solid hydrates are stored on continental margins and in permafrost regions. If these CH4 hydrates could be converted into CO2 hydrates, they would serve double duty as CH4 sources and CO2 storage sites. We explore here the swapping phenomenon occurring in structure I (sI) and structure II (sII) CH4 hydrate deposits through spectroscopic analyses and its potential application to CO2 sequestration at the preliminary phase. The present 85% CH4 recovery rate in sI CH4 hydrate achieved by the direct use of binary N2+CO2 guests is surprising when compared with the rate of 64% for a pure CO2 guest attained in the previous approach. The direct use of a mixture of N2+CO2 eliminates the requirement of a CO2 separation/purification process. In addition, the simultaneously occurring dual mechanism of CO2 sequestration and CH4 recovery is expected to provide the physicochemical background required for developing a promising large-scale approach with economic feasibility. In the case of sII CH4 hydrates, we observe a spontaneous structure transition of sII to sI during the replacement and a cage-specific distribution of guest molecules. A significant change of the lattice dimension caused by structure transformation induces a relative number of small cage sites to reduce, resulting in the considerable increase of CH4 recovery rate. The mutually interactive pattern of targeted guest-cage conjugates possesses important implications for the diverse hydrate-based inclusion phenomena as illustrated in the swapping process between CO2 stream and complex CH4 hydrate structure.
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PMID:Sequestering carbon dioxide into complex structures of naturally occurring gas hydrates. 1690 54

New technology by ICA for chemical generation of carbon dioxide (CO2) was evaluated in olfactometer and large outdoor cage tests against laboratory-reared Aedes aegypti for potential use in mosquito surveillance programs. The proprietary CO2 generation system consists of a poly-Tyvek sachet containing 2 solid ingredients. Activated sachets immediately react to generate and release predictable levels of CO2 over time. In noncompetitive olfactometer studies, a freshly activated sachet attracted an average +/- SE of 96.6 +/- 0.9% of the available mosquitoes compared with 20.2 +/- 6.5% for 5 ml/min CO2 released from a compressed gas cylinder. In competitive tests, the sachet attracted 92.4 +/- 1.2% compared with 0.9 +/- 0.5% for the compressed gas. In the olfactometer, aged sachets attracted >90% of the available mosquitoes up to 8 h and ca. 27% 1 wk after activation. In the large outdoor cages, traps baited with activated sachets captured 2.2-5.4 times as many mosquitoes as unbaited traps, depending on time of testing after activation.
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PMID:Olfactometer and large cage evaluation of a solid phase technology for the controlled production of CO2. 1706 34

The effect of pressure on supercritical carbon dioxide (scCO2) has been characterized by using Car-Parrinello molecular dynamics simulations. Structural and dynamical properties along an isotherm of 318.15 K and at pressures ranging from 190 to 5000 bar have been obtained. Intermolecular pair correlation functions and three-dimensional atomic probability density map calculations indicate that the local environment of a central CO2 molecule becomes more structured with increasing pressure. The closest neighbors are predominantly oriented in a distorted T-shaped geometry while neighbors separated by larger distances are likely oriented in a slipped parallel arrangement. The structure of scCO2 at high densities has been compared with that of crystalline CO2. The probability distributions of intramolecular distances narrow down with increasing pressure. A marginal but non-negligible effect of pressure on the instantaneous intramolecular OCO angle is observed, lending credence to the idea that intermolecular interactions between CO2 molecules in an inhomogeneous near neighbor environment could contribute to the observed instantaneous molecular dipole moment. The extent of deviation from a perfect linear geometry of the carbon dioxide molecule decreases with increasing pressure. Time constants derived from reorientational time correlation functions of the molecular backbone compare well with experimental data. Within the range of thermodynamic conditions explored here, no significant changes are observed in the frequencies of intramolecular vibrational modes. However, a blue shift is observed in the low-frequency cage rattling mode with increasing pressure.
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PMID:Evolution of intermolecular structure and dynamics in supercritical carbon dioxide with pressure: an ab initio molecular dynamics study. 1721 90

We developed a CO2 euthanasia system that functions as an individually ventilated caging system and that accommodates the simultaneous euthanasia of as many as 70 cages of mice. The automated, logic-controlled system allows euthanasia of mice in their home cage, provides consistent and reproducible delivery of CO2, permits visualization of animals during euthanasia, and integrates various safety features. Requirements for the safe use of this system are that all cage locations are to be filled and that engineering controls (that is, a thimble connection) be used to minimize CO2 contamination of the immediate environment. The system was evaluated using mice that were nongravid and greater than 6 d of age. CO2 measurements were made over time to assess the reproducibility of intracage CO2 levels and the effect of 3 supply plenum pressures (0.35, 0.25, and 0.15 in. H2O) on maximal intracage CO2 concentration, CO2 fill slope, time until CO2 detection, and time until maximal CO2 concentration. Results indicate that both supply plenum pressure and cage position on the rack affect intracage CO2 concentrations. We also conducted behavioral assessments of mice undergoing euthanasia to evaluate distress during euthanasia at 2 plenum pressures (0.15 and 0.35 in. H2O). Personnel experienced with laboratory mice did not discern differences in mouse distress associated with either cage location or plenum pressure. This system was safe, effective, and labor-saving for euthanizing large numbers of mice in an aesthetically acceptable and humane manner compatible with recommendations provided in the ACLAM 2005 Report on Euthanasia.
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PMID:Automated mouse euthanasia in an individually ventilated caging system: system development and assessment. 1734 56


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