Antipollution system to remove nitrogen dioxide gas

Gas phase reaction system using anhydrous ammonia removes nitrogen dioxide. System consists of ammonia injection and mixing section, reaction section /reactor/, and scrubber section. All sections are contained in system ducting

Degradation of Phosphorene in Air: Understanding at Atomic Level

Phosphorene is a promising two dimensional (2D) material with a direct band gap, high carrier mobility, and anisotropic electronic properties. Phosphorene-based electronic devices, however, are found to degrade upon exposure to air. In this paper, we provide an atomic level understanding of stability of phosphorene in terms of its interaction with O2 and H2O. The results based on density functional theory together with first principles molecular dynamics calculations show that O2 could spontaneously dissociate on phosphorene at room temperature. H2O will not strongly interact with pristine phosphorene, however, an exothermic reaction could occur if phosphorene is first oxidized. The pathway of oxidation first followed by exothermic reaction with water is the most likely route for the chemical degradation of the phosphorene-based devices in air

Reactivity of neutral and charged B13 clusters with O2: A theoretical study

The chemical reactivity of neutral, cationic, and anionic species of the gas phase B13 cluster with molecular oxygen, O2, was investigated using density functional theory. All three species of B 13 interact with an oxygen molecule to generate a variety of stable isomers, with those representing a dissociative chemisorption process forming the most stable configurations. Our results also show site-specific bonding of oxygen to the B13(+/0/-) cluster. The effect of sequential ionization on the formation of products is pronounced. In ionic B13 clusters, in addition to energetics, the spin of the reactants and products plays a vital role in determining the most favorable product channel. In addition, this study reveals a richness of phenomena requiring a unified consideration of energy, geometry, spin conversion, and details of the electronic structure not previously illustrated for the reactivity of boron clusters. © 2010 American Institute of Physics

Rapid Multiplexed Data Acquisition: Application To Three-Dimensional Magnetic Field Measurements In A Turbulent Laboratory Plasma

Multiplexing electronics have been constructed to reduce the cost of high-speed data acquisition at the Swarthmore Spheromak Experiment (SSX) and Redmond Plasma Physics Laboratory. An application of the system is described for a three-dimensional magnetic probe array designed to resolve magnetohydrodynamic time scale and ion inertial spatial scale structure of magnetic reconnection in a laboratory plasma at SSX. Multiplexing at 10 MHz compresses 600 pick-up coil signals in the magnetic probe array into 75 digitizer channels. An external master timing system maintains synchronization of the multiplexers and digitizers. The complete system, calibrated and tested with Helmholtz, line current, and magnetofluid fields, reads out the entire 5 x 5 x 8 probe array every 800 ns with an absolute accuracy of approximately 20 G, limited mainly by bit error. (C) 2003 American Institute of Physics

The longitudinal effect of ejaculation on seminal vesicle fluid volume and whole-prostate ADC as measured on prostate MRI.

OBJECTIVE: To prospectively investigate the longitudinal effect of ejaculatory abstinence on MRI-measured seminal vesicle (SV) volume and whole-prostate ADC over consecutive days. METHODS: 15 healthy male volunteers (mean 35.9 years, range 27-53) underwent 3-T MRI at baseline and 1, 2 and 3 days post-ejaculation. Prostate and SV volumes were derived by volume segmentation and whole-gland apparent diffusion coefficient (ADC) values calculated. A mixed-effects linear regression compared ADC values and prostate/seminal vesicle volumes in each volunteer between studies in a pairwise manner. RESULTS: All subjects completed the four MRIs. Mean prostate volume was 22.45 cm³ (range 13.04-31.21 cm³), with no change between the four studies (p = 0.89-0.99). 13/15 subjects showed SV volume reduction from baseline to day 1, with group-mean decreasing from 6.45 to 4.80 cm³ (-25.6%, p < 0.001), and a significant reduction from baseline to day 2 (-18.1%, p = 0.002). There was a significant volume increase from both day 1 (+21.3%, p = 0.006) and day 2 (+10.2%, p = 0.022) to day 3 post-ejaculation. There was a significant reduction in ADC from 1.105 at baseline to 1.056 × 10¯³ mm²/s at day 1 (mean -4.3%, p = 0.009). CONCLUSION: The longitudinal effect of ejaculation on SV volume was demonstrated. Significant reductions in SV volume and whole-gland ADC were observed post-ejaculation, supporting a 3-day period of abstinence before prostate MRI. KEY POINTS: • Seminal vesicle volume significantly reduced 24 h post-ejaculation remaining reduced at day 2 • Seminal vesicle fluid volume significantly increased from day 1 to day 3 post-ejaculation • There was a significant reduction in whole-gland prostate ADC values day 1 post-ejaculation • 3-day abstinence from ejaculation is required to ensure maximal seminal vesicle distension.The authors acknowledge grant support from the Royal College of Radiologists UK and research support from Cancer Research UK, National Institute of Health Research Cambridge Biomedical Research Centre, Cancer Research UK and the Engineering and Physical Sciences Research Council Imaging Centre in Cambridge and Manchester and the Cambridge Experimental Cancer Medicine Centre

Carbon-Carbon bond forming reactions of organotransition metal enolate complexes

Abstract -Metal enolates play an important role in stereoselective organic synthesis. Their chemistry is affected profoundly by the metal counterion associated with the enolate fragment. In order to expand the potential of replacing main group with transition metal moieties in such species, methods have been developed for the synthesis of a number of stable, characterizable &quot;late&quot; transition metal ql-(C)-enolate complexes having the general structure LM-CH2COR (M = Mo, W, Re). The chemistry of these materials (e.g., functional transformations of the organic carbonyl group, transfer of the enolate moietry to organic substrates such as aldehydes and alkynes) has been investigated. The scope and mechanisms of the enolate reactions will be discussed in detail. The reaction of organic enolates with carbon electrophiles (e.g., alkyl halides, organic carbonyl compounds) gives rise to compounds containing new carbon-carbon bonds; reaction with heteroatom electrophiles results in the formation of oxidized products? There has been much interest recently in developing methods for carrying out these transformations with high stereoselectivity.3 Historically, most enolate research has focused on salts involving alkali metal anions. More recently, research efforts have been extended to enolates associated with organic cations, main group metals, and transition metals. In the transition metal area, enolates involving the so-called &quot;early&quot; metals (to the left of chromium, molybdenum and tungsten) have seen extensive investigationi4 in general these complexes have 0-bonded structures A in Scheme 1. This paper describes the synthesis and chemistry of middle-and late transition metal enolates, which have seen less investigation. It was our hope that such species would be more likely to have Cbound structure B, and also to react with both electrophilic and non-electrophilic species (e.g., by insertion rather than nucleophile-electrophile mechanisms). SYNTHESIS, CHARACTERIZATION AND FUNCTIONAL GROUP TRANSFORMATIONS OF TUNGSTEN AND MOLYBDENUM ENOLATES The well-known nucleophilic anionic metal salts5 Na[(qS-C5R5)(C0)3M] (M = Mo, W, R=H, Me), on treatment with a-chloroketones and esters, provide good yields of enolates 1 -8, as shown in Scheme 2. These are thermally stable complexes that may be isolated by conventional chromatographic and recrystallization methods; they have been characterized fully by elemental analysis and spectroscopic techniques. Preparation of these materials on a multi-gram scale in a one-pot procedure is possible by treatment of W(CO)6 or Mo(C0)6 with NaCp, followed by addition of the a-chlorocarbonyl compound to the resulting metal anion solution. The stability of the tungsten-carbon bond in tungsten ester enolates, fiist suggested several years ago by the work of Green and his coworkers6, has allowed us to carry out a wide range of transformations on the organic carbonyl group. Thus the reactions shown in Scheme 3 proceed in good yield, and lead to stable tungsten enolates containing ester, amide and even carboxylic acid and acid chloride functionality

Quantifying normal human brain metabolism using hyperpolarized [1– 13 C]pyruvate and magnetic resonance imaging

Hyperpolarized 13 C Magnetic Resonance Imaging ( 13 C-MRI) provides a highly sensitive tool to probe tissue metabolism in vivo and has recently been translated into clinical studies. We report the cerebral metabolism of intravenously injected hyperpolarized [1– 13 C]pyruvate in the brain of healthy human volunteers for the first time. Dynamic acquisition of 13 C images demonstrated 13 C-labeling of both lactate and bicarbonate, catalyzed by cytosolic lactate dehydrogenase and mitochondrial pyruvate dehydrogenase respectively. This demonstrates that both enzymes can be probed in vivo in the presence of an intact blood-brain barrier: the measured apparent exchange rate constant (k PL ) for exchange of the hyperpolarized 13 C label between [1– 13 C]pyruvate and the endogenous lactate pool was 0.012 ± 0.006 s −1 and the apparent rate constant (k PB ) for the irreversible flux of [1– 13 C]pyruvate to [ 13 C]bicarbonate was 0.002 ± 0.002 s −1 . Imaging also revealed that [1– 13 C]pyruvate, [1– 13 C]lactate and [ 13 C]bicarbonate were significantly higher in gray matter compared to white matter. Imaging normal brain metabolism with hyperpolarized [1– 13 C]pyruvate and subsequent quantification, have important implications for interpreting pathological cerebral metabolism in future studies

Hyperpolarized13c mri of tumor metabolism demonstrates early metabolic response to neoadjuvant chemotherapy in breast cancer

Purpose: To compare hyperpolarized carbon 13 (13C) MRI with dynamic contrast material–enhanced (DCE) MRI in the detection of early treatment response in breast cancer. Materials and Methods: In this institutional review board–approved prospective study, a woman with triple-negative breast cancer (age, 49 years) underwent13C MRI after injection of hyperpolarized [1–carbon 13 {13C}]-pyruvate and DCE MRI at 3 T at baseline and after one cycle of neoadjuvant therapy. The13C-labeled lactate-to-pyruvate ratio derived from hyperpolarized13C MRI and the pharmacokinetic parameters transfer constant (Ktrans) and washout parameter (kep ) derived from DCE MRI were compared before and after treatment. Results: Exchange of the13C label between injected hyperpolarized [1-13C]-pyruvate and the endogenous lactate pool was observed, catalyzed by the enzyme lactate dehydrogenase. After one cycle of neoadjuvant chemotherapy, a 34% reduction in the13C-labeled lactate-to-pyruvate ratio resulted in correct identification of the patient as a responder to therapy, which was subsequently confirmed via a complete pathologic response. However, DCE MRI showed an increase in mean Ktrans (132%) and mean kep (31%), which could be incorrectly interpreted as a poor response to treatment. Conclusion: Hyperpolarized13C MRI enabled successful identification of breast cancer response after one cycle of neoadjuvant chemotherapy and may improve response prediction when used in conjunction with multiparametric proton MRI

Hyperpolarized 13C-MRI of Tumor Metabolism Demonstrates Early Metabolic Response to Neoadjuvant Chemotherapy in Breast Cancer

Purpose: To compare hyperpolarized carbon-13 (13C)-MRI with dynamic contrast-enhanced MRI (DCE-MRI) for detecting early treatment response in breast cancer. Materials and Methods: In this institutional review board-approved prospective study, one woman with triple-negative breast cancer (age 49) underwent 13C-MRI following injection of hyperpolarized [1-13C]pyruvate and DCE-MRI at 3 T at baseline and after a single cycle of neoadjuvant therapy. The 13C-lactate/13C-pyruvate ratio derived from hyperpolarized 13C-MRI and the pharmacokinetic parameters Ktrans and kep derived from DCE-MRI were compared, before and after treatment. Results: Exchange of the 13C-label between injected hyperpolarized [1-13C]pyruvate and the endogenous lactate pool was demonstrated, catalyzed by the enzyme lactate dehydrogenase. After one cycle of neoadjuvant chemotherapy, a 34% reduction in the 13C-lactate/13C-pyruvate ratio was shown to correctly identify the patient as a responder to therapy, which was subsequently confirmed by a complete pathologic response. However, DCE-MRI showed an increase in the pharmacokinetic parameters Ktrans (132%) and kep (31%), which could be incorrectly interpreted as a poor response to treatment. Conclusion: Hyperpolarized 13C-MRI successfully identified response in breast cancer after a single cycle of neoadjuvant chemotherapy and may improve response prediction when used in conjunction with multiparametric proton MRI.This work was supported by a Wellcome Trust Strategic Award, Cancer Research UK (CRUK; Grants C8742/A18097, C19212/ A16628, C19212/A911376, and C197/A16465), the Austrian Science Fund (Grant J4025-B26), the CRUK Cambridge Centre, the CRUK & Engineering and Physical Sciences Research Council Cancer Imaging Centre in Cambridge and Manchester, the Mark Foundation for Cancer Research and Cancer Research UK Cambridge Centre (Grant C9685/A25177), CRUK National Cancer Imaging Translational Accelerator Award, Addenbrooke’s Charitable Trust, the National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge Experimental Cancer Medicine Centre, and Cambridge University Hospitals National Health Service Foundation Trust