214 research outputs found
The Real Corrections to the Gamma* Impact Factor: First Numerical Results
We have performed analytically the transverse momentum integrations in the
real corrections to the longitudinal \gamma^*_L impact factor and carried out
numerically the remaining integrations. I outline the analytical integration
and present the numerical results: we have performed a numerical test and
computed those parts of the impact factor that depend upon the energy scale
s_0.Comment: 4 pages, 3 figures, to appear in proceedings of "DIS 2004", XII
International Workshop on Deep Inelastic Scattering (April 2004, Strbske
Pleso, Slovakia
Offset frequency dynamics and phase noise properties of a self-referenced 10 GHz Ti:sapphire frequency comb
This paper shows the experimental details of the stabilization scheme that
allows full control of the repetition rate and the carrier-envelope offset
frequency of a 10 GHz frequency comb based on a femtosecond Ti:sapphire laser.
Octave-spanning spectra are produced in nonlinear microstructured optical
fiber, in spite of the reduced peak power associated with the 10 GHz repetition
rate. Improved stability of the broadened spectrum is obtained by
temperature-stabilization of the nonlinear optical fiber. The carrier-envelope
offset frequency and the repetition rate are simultaneously frequency
stabilized, and their short- and long-term stabilities are characterized. We
also measure the transfer of amplitude noise of the pump source to phase noise
on the offset frequency and verify an increased sensitivity of the offset
frequency to pump power modulation compared to systems with lower repetition
rate. Finally, we discuss merits of this 10 GHz system for the generation of
low-phase-noise microwaves
Синтез новых азотсодержащих соединений на основе бетулина и мочевин
High-speed asynchronous optical sampling is used for the rapid and precise determination of transmission resonances of terahertz surface sensors based on asymmetric double split ring resonator arrays. The sensor response represented by a characteristic resonant frequency is determined to 0.66113 THz with an accuracy of +325 MHz within 2 seconds of read-out time
Изучение процессов осадконакопления с помощью цепей Маркова
Two femtosecond Ti:sapphire lasers with slightly different repetition rates near 1 GHz are coupled to implement high-speed asynchronous optical sampling. The application of this technique is successfully demonstrated in the field of terahertz time-domain spectroscopy (TDS). A time delay of 1 ns is scanned at a frequency of 5 kHz without moving mechanical parts. Compared with that of conventional TDS schemes based on lock-m detection and moving mirrors, the readout time of integrated resonant THz sensors is reduced by a factor of 20, opening the way for high-throughput THz sensing in marker-free DNA analysis
A high throughput molecular force assay for protein-DNA interactions.
An accurate and genome-wide characterization of protein–DNA interactions such as transcription factor binding is of utmost importance for modern biology. Powerful screening methods emerged. But the vast majority of these techniques depend on special labels or markers against the ligand of interest and moreover most of them are not suitable for detecting low-affinity binders. In this article a molecular force assay is described based on measuring comparative unbinding forces of biomolecules for the detection of protein–DNA interactions. The measurement of binding or unbinding forces has several unique advantages in biological applications since the interaction between certain molecules and not the mere presence of one of them is detected. No label or marker against the protein is needed and only specifically bound ligands are detected. In addition the force-based assay permits the detection of ligands over a broad range of affinities in a crowded and opaque ambient environment. We demonstrate that the molecular force assay allows highly sensitive and fast detection of protein–DNA interactions. As a proof of principle, binding of the protein EcoRI to its DNA recognition sequence is measured and the corresponding dissociation constant in the sub-nanomolar range is determined. Furthermore, we introduce a new, simplified setup employing FRET pairs on the molecular level and standard epi-fluorescence for readout. Due to these advancements we can now demonstrate that a feature size of a few microns is sufficient for the measurement process. This will open a new paradigm in high-throughput screening with all the advantages of force-based ligand detection.
Graphical abstract: A high throughput molecular force assay for protein–DNA interaction
Экспериментальное обоснование эффективности газовых инфракрасных излучателей как элемента системы отопления производственных помещений
В рамках работы экспериментально установлены температурные поля поверхностей и температуры воздуха внутри производственного помещения при работе газового инфракрасного излучателя.
В результате экспериментального исследования определено влияние расположения газового инфракрасного излучателя и типа поверхности пола на интенсивность теплопереноса в помещении.
Разработана методика проведения эксперимента. Получены температурные поля для двух типов поверхностей пола (бетон + бетон, бетон + керамика) и проведен анализ распределений по пространственным координатам X и Y.
Для установления распределения тепловой энергии излучателем, непосредственно затрачиваемой на нагрев воздуха рабочей зоны сформулирована математическая модель с описанием физической и геометрической модели.As part of the work, the temperature fields of surfaces and air temperatures inside the production room were experimentally established during operation of a gas infrared emitter.
As a result of an experimental study, the influence of the location of the gas infrared emitter and the type of floor surface on the intensity of heat transfer in the room is determined.
An experimental technique has been developed. Temperature fields were obtained for two types of floor surfaces (concrete + concrete, concrete + ceramics), and the distribution of spatial coordinates X and Y was analyzed.
To establish the distribution of thermal energy by the emitter, directly spent on heating the air of the working area, a mathematical model is formulated with a description of the physical and geometric model
Ascites’ neutrophil function is significantly impaired in patients with decompensated cirrhosis but can be restored by autologous plasma incubation
Systemic immune cell dysfunction is a typical feature of liver diseases and
increases the risk of bacterial infection, especially spontaneous bacterial
peritonitis. We evaluated functional properties of neutrophil granulocytes in
blood and ascites of patients both with and without decompensated cirrhosis.
We collected blood and ascites samples from 63 patients with cirrhosis and
eight without cirrhosis. Phagocytosis activity (PA) and oxidative burst
activity (OBA) were evaluated after ex vivo stimulation with E. coli, while
fluorescence signals were measured by flow cytometry. Ascites’ neutrophil
function tests were repeated after incubation with autologous plasma. Ascites’
neutrophils showed an impaired PA and OBA (median blood PA 98.1% (86.8–99.8)
vs. ascites’ PA 50.5% (0.4–97.3), p < 0.0001; median blood OBA 98.7%
(27.5–100) vs. ascites’ OBA 27.5% (0.3–96.7), p < 0.0001). Patients with non-
cirrhotic ascites showed higher PA but equally suppressed OBA. Ascites’
neutrophil function could be partially restored after incubation with
autologous plasma (median increase PA: 22.5% (−49.7 – +93.2), p = 0.002; OBA:
22.8% (−10.4 – +48.8), p = 0.002). Ascites’ neutrophils of patients with
cirrhosis are functionally impaired, but could be partially restored after
incubation with plasma. Further investigations are needed to identify the
factors in ascites that are associated with neutrophils’ function
- …