Search results for "Trap"
showing 10 items of 2144 documents
Trapping and Immobilization of DNA Molecules Between Nanoelectrodes
2011
DNA is one of the most promising molecules for nanoscale bottom-up fabrication. For both scientific studies and fabrication of devices, it is desirable to be able to manipulate DNA molecules, or self--assembled DNA constructions, at the single unit level. Efficient methods are needed for precisely attaching the single unit to the external measurement setup or the device structure. So far, this has often been too cumbersome to achieve, and consequently most of the scientific studies are based on a statistical analysis or measurements done for a sample containing numerous molecules in liquid or in a dry state. Here, we explain a method for trapping and attaching nanoscale double-stranded DNA …
Rotational spectra of isotopic species of silyl fluoride. Part II: theoretical and empirical equilibrium structure
2010
Abstract The equilibrium structure of silyl fluoride, SiH 3 F, has been reinvestigated using both theoretical and experimental data. With respect to the former, quantum-chemical calculations at the coupled-cluster level have been employed together with extrapolation to the basis set limit, consideration of higher excitations in the cluster operator, and inclusion of core correlation as well as relativistic corrections ( r (Si–F) = 1.5911 A, r (Si–H) = 1.4695 A, and ∠FSiH = 108.30°). A semi-experimental equilibrium structure has been determined based on the available rotational constants for the various isotopic species of silyl fluoride ( 28 SiH 3 F, 28 SiD 3 F, 29 SiH 3 F, 29 SiD 3 F, 30 S…
The complexation of tetraphenylborate with organic N-heteroaromatic cations
2001
Complexation studies of eleven N-heteroaromatic cations with tetraphenylborate are reported. Tetraphenylborate forms complexes with five cations and reacts to form Lewis-base boranes with six cations. The complexes and the displacement reaction products were characterised by 1H NMR spectroscopy, elemental analysis and crystallographic methods. In the complexes C–H⋯π or N–H⋯π hydrogen bonds are the principal intermolecular interactions. The stability constants for the complexes are determined by 1H NMR titration in acetonitrile–methanol (1 ∶ 1) solution. Crystal structures of four of the complexes and three of the Lewis-base triphenylborane products are reported.
Oligamide mit definierter verzweigung. Lineare und cyclische oligomere. XIV.
1965
Synthese und chemische Eigenschaften des ersten verzweigten, molekulareinheitlichen Oligoamids mit definierter Struktur werden beschrieben. N,N-[Di-(ϵ-aminocaproyl)]-ϵ-aminocapronsaure (V), ein Oligomeres aus drei Aminocapronsaureresten mit einer Acylamidverzweigung, wurde durch Acylierung der Saureamidgruppe einer amino- und carboxyl-geschutzten Di-ϵ-aminocapronsaure mit einem N-geschutzten ϵ-Aminocaproylchlorid und nachfolgender Abspaltung aller Schutzgruppen als Hydrochlorid bzw. Tetraphenylborat in analysenreiner Form gewonnen. In neutralem und alkalischem Medium erleidet es bereits unter milden Bedingungen Polykondensation. The synthesis and chemical properties of the first branched, m…
Absolute cross-sections for the nonresonant multi-photon ionization of toluene and xylene in the gas phase
2001
Abstract The absolute multi-photon ionization cross-section of the phenyl ring was determined by laser-ionization of toluene and xylene molecules in the gas phase. Excitation was achieved using nonresonant four-photon absorption of the frequency doubled light of a 10 ns pulsed Nd:YAG laser (532 nm). The resulting ions were stored in a Penning trap and detected by time-of-flight mass spectrometry. The values of the cross-sections are 1.4(3)×10 −42 cm 8 W −4 s −1 and 1.3(3)×10 −42 cm 8 W −4 s −1 for toluene and xylene, respectively.
DELAYED ELECTRON EMISSION OF NEGATIVELY CHARGED TUNGSTEN CLUSTERS
1996
The delayed electron emission of negatively charged tungsten clusters has been investigated on a time scale from 1 to 500 ms. After being stored in a Penning trap clusters ions [Formula: see text] were heated via multiphoton absorption (hν=1.81 eV). In contrast to alkali and coinage metals no photofragmentation could be detected. Instead, for all cluster sizes studied so far only a decrease in the initial ion intensity as a function of time after excitation was observed. This decrease is not caused by ion loss from the trap, but has to be attributed to neutralization via delayed electron emission. The presented results strongly suggest that this process can be viewed as “thermionic emissio…
Flogosi post-trapianto di cornea
2013
Il Trapianto di Cornea, o Cheratoplastica, che prevede la sostituzione sub-totale della cornea mediante un innesto circolare di tessuto omologo (lembo), rappresenta la procedura d’elezione per il trattamento di diverse patologie corneali congenite o acquisite. Se ne discutono tutti i determinanti e le prospettive.
CCDC 2057854: Experimental Crystal Structure Determination
2021
Related Article: Todd N. Poe, Maria J. Beltra��n-Leiva, Cristian Celis-Barros, William L. Nelson, Joseph M. Sperling, Ryan E. Baumbach, Harry Ramanantoanina, Manfred Speldrich, Thomas E. Albrecht-Scho��nzart|2021|Inorg.Chem.|60|7815|doi:10.1021/acs.inorgchem.1c00300
Removal of Chromophore-proximal Polar Atoms Decreases Water Content and Increases Fluorescence in a Near Infrared Phytofluor
2015
Genetically encoded fluorescent markers have revolutionized cell and molecular biology due to their biological compatibility, controllable spatiotemporal expression, and photostability. To achieve in vivo imaging in whole animals, longer excitation wavelength probes are needed due to the superior ability of near infrared light to penetrate tissues unimpeded by absorbance from biomolecules or autofluorescence of water. Derived from near infrared-absorbing bacteriophytochromes, phytofluors are engineered to fluoresce in this region of the electromagnetic spectrum, although high quantum yield remains an elusive goal. An invariant aspartate residue is of utmost importance for photoconversion in…
Estándares de calidad en la cirugía de carcinomatosis peritoneal de origen colorectal mediante citorreducción y quimioterapia intraperitoneal hiperte…
2020
El mayor conocimiento de la historia natural de la carcinomatosis peritoneal ha permitido su valoración como una progresión locorregional. Tras los trabajos publicados por Sugarbaker tanto a nivel quirúrgico, con la descripción de las técnicas de peritonectomía como a nivel farmacológico experimental para la aplicación de la quimioterapia intraperitoneal hipertérmica (HIPEC), se considera un tratamiento locorregional de la enfermedad confinada al abdomen. Así, una cirugía radical de citorreducción con extirpación de la enfermedad macroscópica y la aplicación posterior de HIPEC para control de la enfermedad microscópica residual, ha obtenido resultados muy superiores a la quimioterapia aisla…