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1.
I. W. Fraser J. L. Garnett I. K. Gregor K. J. Jessop 《Journal of mass spectrometry : JMS》1975,10(1):69-73
Negative ion mass spectra of series of bis-(N, N-dithiocarbamato)nickel(II) complexes of formula [NiS2C·NR1R2]2 (where·NR1R2 ? ·NEt2 ·NPr2, ·NBu2, pyrrolidinyl, piperidyl, morpholinyl, and ·NEtPh) have been obtained by secondary electron capture. Intense molecular anions are given for all compounds, with most fragments originating from these ions. Metastable data indicate that CS2 is eliminated from all molecular anions. 相似文献
2.
Summary The applicability of capillary electrochromatography to the automated analysis of pesticides and phthalate esters that are
of environmental concern was assessed. Reversed phase packing materials were compared. Column to column and run to run reproducibility
was established. Peak height with an internal standard gave the best reproducibility. Faster analysis than alternative HPLC
methods was demonstrated for a mixture of the insecticide pirimicarb and related pyrimidines. The relationship between the
concentration of an analyte in a sample and at the detector was determined by the use of radio-labelled14C-pirimicarb. The volume fraction of the liquid zone was 0.64. The possibility of electroosmosis through the pores is discussed
with reference to the Rice-Whitehead model for electroosmotic flow in a capillary. A new parameter, the effective pore size
is used in equations for electroosmosis through porous packings. 相似文献
3.
Brian Dillman Julie L. P. Jessop 《Journal of polymer science. Part A, Polymer chemistry》2013,51(9):2058-2067
The effects of chain transfer agents (CTA) on cationic ring‐opening polymerization of 3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate (EEC) were explored. EEC was polymerized in the presence of various CTAs, and epoxide conversions monitored via Raman spectroscopy. Polymer films were prepared and analyzed by dynamic mechanical analysis. Many of the organic alcohols studied greatly enhanced epoxide polymerization rates and conversion levels. The gel fraction of polymer specimens decreased rapidly with increasing amounts of octanol (gel fraction >90% up to 0.3 equiv OH) but remained high with increasing amounts of 1,2‐propanediol (gel fraction >90% up to 0.6 equiv OH). Increasing the size of primary alcohols had little effect on the polymerization rates and conversions. The polymerization rate decreased with increasing alcohol substitution (1°>2°>3°). Acidic alcohols had very low impact on conversion and polymerization rates relative to the neat epoxy resin. The glass transition temperature was inversely related to the size and amount of CTA. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
4.
5.
A. P. Knights J. J. Ackert D. F. Logan E. Huante-Ceron P. E. Jessop 《Optical and Quantum Electronics》2012,44(12-13):575-580
In this paper we outline two recent results which demonstrate the utility of deep-level engineering in silicon photonics. We describe the integration of silicon waveguide p-i-n photo-detectors in a ring (or race-track) resonator structure. The detectors are made sensitive to wavelengths around 1,550?nm via the introduction of deep-levels into the intrinsic volume of the waveguide detector. By exploiting the multiple-pass of the optical signal through the detector, we are able to significantly decrease the size of the detector structure (relative to straight waveguide detectors) while maintaining excellent responsivity on resonance. We also describe the use of deep-levels for optical modulation. Preliminary results show that thallium doped silicon waveguides may be switched between a dark and transparent condition through the variation of phosphorus doping. It is suggested that active devices may be fabricated in such a way as to vary the occupancy of the thallium level through field mediated modulation. The straightforward fabrication methods described lend themselves to a high-volume, high yield manufacturing process which should find general applicability in wavelength division multiplexing systems. 相似文献
6.
Wender PA Rothbard JB Jessop TC Kreider EL Wylie BL 《Journal of the American Chemical Society》2002,124(45):13382-13383
Molecular transporters have the ability to deliver drugs and probe molecules into cells and tissues irrespective of their physical properties. We now report the design, synthesis, and biological evaluation of a new family of molecular transporters, guanidinylated oligocarbamates that enable exceptionally efficient uptake into cells and tissues. The synthesis features a solid-phase stepwise oligomerization to obtain the oligocarbamates and a single step perguanidinylation for the facile introduction of up to nine guanidinium groups. The oligocarbamate 9-mer is found to be among the most efficient transporters known, entering cells faster than even d-Arg9 and HIV-1 Tat49-57. Significantly, this new family of transporters also enables uptake into the formidable skin barrier of a probe molecule that by itself does not penetrate skin. 相似文献
7.
An improved capillary electrophoresis assay for histamine in crude extracts was developed and used to determine histamine levels in a selection of tomato fruits and pastes. Performance in terms of reproducibility and sensitivity was optimized by use of a high sensitivity detector flow cell, sodium hydroxide rinses, and a voltage gradient. The method was linear down to 0.2 microgram/mL (signal-to-noise ratio = 4:1), which was below the endogenous level in all samples. 相似文献
8.
Nanotube molecular transporters: internalization of carbon nanotube-protein conjugates into Mammalian cells 总被引:20,自引:0,他引:20
Shi Kam NW Jessop TC Wender PA Dai H 《Journal of the American Chemical Society》2004,126(22):6850-6851
The interactions between various functionalized carbon nanotubes and several types of human cancer cells are explored. We have prepared modified nanotubes and have shown that these can be derivatized in a way that enables attachment of small molecules and of proteins, the latter through a novel noncovalent association. The functionalized carbon nanotubes enter nonadherent human cancer cells as well as adherent cell lines (CHO and 3T3) and by themselves are not toxic. While the fluoresceinated protein streptavidin (MW approximately 60 kD) by itself does not enter cells, it readily enters cells when complexed to a nanotube-biotin transporter and exhibits dose-dependent cytotoxicity. The uptake pathway is consistent with adsorption-mediated endocytosis. The use of carbon nanotubes as molecular transporters could be exploited for various cargos. The biocompatibility and unique physical, electrical, optical, and mechanical properties of nanotubes provide the basis for new classes of materials for drug, protein, and gene delivery applications. 相似文献
9.
A simple method for high-pressure combinatorial catalyst discovery with visual (dye-based) assay is described. With this method, the first highly active catalyst, incorporating metals outside the platinum group, has been identified for CO(2) hydrogenation. 相似文献
10.
Ammar R Bean A Besson D Davis R Kwak N Zhao X Anderson S Frolov VV Kubota Y Lee SJ Mahapatra R O'Neill JJ Poling R Riehle T Smith A Stepaniak CJ Urheim J Ahmed S Alam MS Athar SB Jian L Ling L Saleem M Timm S Wappler F Anastassov A Duboscq JE Eckhart E Gan KK Gwon C Hart T Honscheid K Hufnagel D Kagan H Kass R Pedlar TK Schwarthoff H Thayer JB von Toerne E Zoeller MM Richichi SJ Severini H Skubic P Undrus A Chen S Fast J Hinson JW Lee J Miller DH Shibata EI Shipsey IP Pavlunin V 《Physical review letters》2001,86(7):1167-1170
Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the Sigma(*+)(c) charmed baryon, and an updated measurement of the mass of the Sigma(+)(c) baryon. We find M(Sigma(*+)(c))-M(Lambda(+)(c)) = (231.0+/-1.1+/-2.0) MeV, and M(Sigma(+)(c))-M(Lambda(+)(c)) = (166.4+/-0.2+/-0.3) MeV, where the errors are statistical and systematic, respectively. 相似文献