146 research outputs found
An analysis of the acoustic cavitation noise spectrum: The role of periodic shock waves
Research on applications of acoustic cavitation is often reported in terms of the features within the spectrum of the emissions gathered during cavitation occurrence. There is, however, limited understanding as to the contribution of specific bubble activity to spectral features, beyond a binary interpretation of stable versus inertial cavitation. In this work, laser-nucleation is used to initiate cavitation within a few millimeters of the tip of a needle hydrophone, calibrated for magnitude and phase from 125 kHz to 20 MHz. The bubble activity, acoustically driven at f0 = 692 kHz, is resolved with high-speed shadowgraphic imaging at 5 × 106 frames per second. A synthetic spectrum is constructed from component signals based on the hydrophone data, deconvolved within the calibration bandwidth, in the time domain. Cross correlation coefficients between the experimental and synthetic spectra of 0.97 for the f 0/2 and f 0/3 regimes indicate that periodic shock waves and scattered driving field predominantly account for all spectral features, including the sub-harmonics and their over-harmonics, and harmonics of f 0
Методика локализации изображения лица для систем видеоконтроля на основе нейронной сети
Предлагается метод и алгоритм локализации лица человека для автоматизированных систем распознавания и видеоконтроля на базе сверточных нейронных сетей. Преимущество использования свёрточных нейронных сетей в том, что они обеспечивают устойчивость к изменениям масштаба, смещениям, поворотам, смене ракурса и другим искажениям входного изображения. Обосновывается топология используемой нейронной сети и методика ее обучения
Primary and malignant cholangiocytes undergo CD40 mediated Fas dependent Apoptosis, but are insensitive to direct activation with exogenous fas ligand
Introduction
Cholangiocarcinoma is a rare malignancy of the biliary tract, the incidence of which is rising, but the pathogenesis of which remains uncertain. No common genetic defects have been described but it is accepted that chronic inflammation is an important contributing factor. We have shown that primary human cholangiocyte and hepatocyte survival is tightly regulated via co-operative interactions between two tumour necrosis family (TNF) receptor family members; CD40 and Fas (CD95). Functional deficiency of CD154, the ligand for CD40, leads to a failure of clearance of biliary tract infections and a predisposition to cholangiocarcinoma implying a direct link between TNF receptor-mediated apoptosis and the development of cholangiocarcinoma.
Aims
To determine whether malignant cholangiocytes display defects in CD40 mediated apoptosis. By comparing CD40 and Fas-mediated apoptosis and intracellular signalling in primary human cholangiocytes and three cholangiocyte cell lines.
Results
Primary cholangiocytes and cholangiocyte cell lines were relatively insensitive to direct Fas-mediated killing with exogenous FasL when compared with Jurkat cells, which readily underwent Fas-mediated apoptosis, but were extremely sensitive to CD154 stimulation. The sensitivity of cells to CD40 activation was similar in magnitude in both primary and malignant cells and was STAT-3 and AP-1 dependent in both.
Conclusions
1) Both primary and malignant cholangiocytes are relatively resistant to Fas–mediated killing but show exquisite sensitivity to CD154, suggesting that the CD40 pathway is intact and fully functional in both primary and malignant cholangiocytes 2) The relative insensitivity of cholangiocytes to Fas activation demonstrates the importance of CD40 augmentation of Fas dependent death in these cells. Agonistic therapies which target CD40 and associated intracellular signalling pathways may be effective in promoting apoptosis of malignant cholangiocytes
Lateral Control by Spoilers at the DVL
The present report describes the development of spoiler control at the DVL from the end of 1936 until the beginning of 1939. The authors are fully aware that the present report also forms only a contribution to the problem of spoiler control and offers at best a possibility of extrapolation regarding the behavior of the control in modern airplanes. A modern airplane (Me 109) is being reconstructed for conversion to spoiler control. Experience has shown, however, that the construction and testing of such a model requires at least a year. Thus it seems appropriate to report summarily now in order to keep the understanding and cooperation of the interested departments aroused. The following reports are only a section of a long development partly evolved abroad
The early bee catches the flower - circadian rhythmicity influences learning performance in honey bees, Apis mellifera
Circadian rhythmicity plays an important role for many aspects of honey bees’ lives. However, the question whether it also affects learning and memory remained unanswered. To address this question, we studied the effect of circadian timing on olfactory learning and memory in honey bees Apis mellifera using the olfactory conditioning of the proboscis extension reflex paradigm. Bees were differentially conditioned to odours and tested for their odour learning at four different “Zeitgeber” time points. We show that learning behaviour is influenced by circadian timing. Honey bees perform best in the morning compared to the other times of day. Additionally, we found influences of the light condition bees were trained at on the olfactory learning. This circadian-mediated learning is independent from feeding times bees were entrained to, indicating an inherited and not acquired mechanism. We hypothesise that a co-evolutionary mechanism between the honey bee as a pollinator and plants might be the driving force for the evolution of the time-dependent learning abilities of bees
In vitro translation of adenovirus type 12-specific mRNA isolated from infected and transformed cells
The early and late gene products of human adenovirus type 12 (Ad12), as well as the viral proteins synthesized in an Ad12-transformed cell line, were identified by translation of viral mRNA in an in vitro protein-synthesizing system. Cytoplasmic RNA was isolated from permissive KB or nonpermissive BHK cells infected with Ad12 and from Ad12-transformed HA12/7 cells. Virus-specific RNA was selected by hybridization to Ad12 DNA covalently bound to cellulose. Viral RNA was then translated in a fractionated rabbit reticulocyte cell-free system or in wheat germ S-30 extracts. The proteins synthesized were characterized by immunoprecipitation and subsequent electrophoresis on sodium dodecyl sulfate-polyacrylamide gels. RNA prepared from KB cells late after infection with Ad12 elicited the synthesis of most of the structural polypeptides of the virion and at least two presumably nonstructural Ad12 proteins. When viral RNA isolated early after infection of KB cells with Ad12 was translated in vitro, 10 polypeptides were observed: E-68K, E-50K, E-42K, E-39K, E-34K, E-21K, E-19K, E-13K, E-12K, and E-10K. Ad12-specific RNA was also isolated from the Ad12-transformed hamster cell line HA12/7, which contains several copies of the Ad12 genome integrated in the host genome. The RNA codes for at least seven polypeptides with molecular weights very similar to those of the early viral proteins.</jats:p
Mens Health: the bacterial extract Broncho-Vaxom® protects against influenza and<i>Salmonella</i>infections
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