2,206 research outputs found

    The small diesel engine as an automotive engine

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    Essential principles for building small diesel engines and also structural details so far as feasibility are presented

    Microtubule dynamics depart from wormlike chain model

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    Thermal shape fluctuations of grafted microtubules were studied using high resolution particle tracking of attached fluorescent beads. First mode relaxation times were extracted from the mean square displacement in the transverse coordinate. For microtubules shorter than 10 um, the relaxation times were found to follow an L^2 dependence instead of L^4 as expected from the standard wormlike chain model. This length dependence is shown to result from a complex length dependence of the bending stiffness which can be understood as a result of the molecular architecture of microtubules. For microtubules shorter than 5 um, high drag coefficients indicate contributions from internal friction to the fluctuation dynamics.Comment: 4 pages, 4 figures. Updated content, added reference, corrected typo

    Ein Beitrag zur Casuistik der multiplen Exostosen : Inaugural-Dissertation zur Erlangung des Grades eines Doctors der Medicin

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    http://tartu.ester.ee/record=b2285059~S1*es

    Persistent memory for a Brownian walker in a random array of obstacles

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    We show that for particles performing Brownian motion in a frozen array of scatterers long-time correlations emerge in the mean-square displacement. Defining the velocity autocorrelation function (VACF) via the second time-derivative of the mean-square displacement, power-law tails govern the long-time dynamics similar to the case of ballistic motion. The physical origin of the persistent memory is due to repeated encounters with the same obstacle which occurs naturally in Brownian dynamics without involving other scattering centers. This observation suggests that in this case the VACF exhibits these anomalies already at first order in the scattering density. Here we provide an analytic solution for the dynamics of a tracer for a dilute planar Lorentz gas and compare our results to computer simulations. Our result support the idea that quenched disorder provides a generic mechanism for persistent correlations irrespective of the microdynamics of the tracer particle.Comment: 11 pages, 4 figures, accepted in Chemical Physic

    Medial adjunct PPs in English: implications for the syntax of sentential negation

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    This paper provides evidence that medial adjunct PPs in English are possible. On the basis of corpus data, it is shown that sentence-medial adjunct PPs are not unacceptable and are attested. Our corpus data also reveal a sharp asymmetry between negative and non-negative adjunct PPs. The analysis of the corpus revealed the following pattern: Non-negative adjunct PPs such as at that time resist medial position and instead tend to be postverbal; negative adjunct PPs such as at no time appear medially rather than postverbally. In the second part of the paper, we broaden the empirical domain and include negative complement PPs in the discussion. It is shown that when it comes to the licensing of question tags, English negative complement PPs, which are postverbal, pattern differently from postverbal negative adjunct PPs. That is, sentences with a postverbal negative adjunct PP pattern with negative sentences in taking a positive question tag, while sentences containing a postverbal negative argument PP pattern with affirmative sentences in taking a negative tag. To account for the observed adjunct-argument asymmetry in the licensing of question tags, we propose that clauses are typed for polarity and we explore the hypothesis that a polarity head in the left periphery of the clause is crucially involved in the licensing of sentential negation

    Expression of the synthetic gene of an artificial DDT-binding polypeptide in Escherichia coli

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    This paper reports the expression of an artificial functional polypeptide in bacteria. The gene of a designed 24-residue DDT-binding polypeptide (DBP) was inserted between the BamHI and PstI cleavage sites of plasmid pUR291. The hybrid plasmid, pUR291-DBP, was cloned in Escherichia coli JM109. After induction by isopropyl-β-D-thiogalactopyranoside a fusion protein was expressed in which DBP was linked to the COOH-termiuus of β-galactosidase. DBP, which is stable to trypsin, was obtained by tryptic digestion of the fusion protein and subsequent fractionation of the tryptic peptides by reversed-phase h.p.l.c. Recombinant and chemically synthesized DBP showed identical chromatographic properties, amino acid composition, and chymotryptic digestion patterns. Both the β-galactosidase-DBP fusion and isolated recombinant DBP bound DDT. The fusion protein was 25 times as potent as the designed 24-residue DBP in activating a cytochrome P-450 model system using equimolar catalytic amounts of the two protein

    Survey Evidence on Conditional Norm Enforcement

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    We discuss survey evidence on individuals' willingness to sanction norm violations - such as evading taxes, drunk driving, fare dodging, or skiving o work - by expressing disapproval or social exclusion. Our data suggest that people condition their sanctioning behavior on their belief about the frequency of norm violations. The more commonly a norm violation is believed to occur, the lower the individuals' inclination to punish it. Based on an instrumental variable approach, we demonstrate that this pattern reflects a causal relationship

    Effect of ultrasonic, thermal and ozone pre-treatments on waste activated sludge solubilisation and anaerobic biodegradability

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    In order to enhance the efficiency of anaerobic digestion, the effects of ultrasounds, ozonation and thermal pre-treatment have been studied on waste activated sludge. The feature of this study was to carry out the comparison of the three pre-treatments in the same conditions and on the same sludge sample. Each treatment was tested in two conditions close to optimum conditions to maximise batch anaerobic sludge biodegradability. All treatments led to chemical oxygen demand and matter solubilisation and had little influence on mineral matter. In terms of solubilisation thermal pre-treatment was better than sonication or ozonation. But, in terms of batch anaerobic biodegradability, best results were obtained with ultrasounds with an energy of 6250 or 9350 kJ/kg TS and a thermal treatment at 170 or 190°C. Moreover, treatments had effects on physicochemical characteristics of sludge samples: apparent viscosity decreased after all treatments but the reduction was more important with thermal treatment. Median diameter of sludge flocs were reduced after sonication, increased after thermal treatment and did not change after ozonation. Finally, capillary suction time (CST) increased after ozonation, increased highly after sonication and was reduced after thermal treatmen

    Priming of Anti-tumor Immune Mechanisms by Radiotherapy Is Augmented by Inhibition of Heat Shock Protein 90

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    Radiotherapy is an essential part of multi-modal cancer therapy. Nevertheless, for certain cancer entities such as colorectal cancer (CRC) the indications of radiotherapy are limited due to anatomical peculiarities and high radiosensitivity of the surrounding normal tissue. The development of molecularly targeted, combined modality approaches may help to overcome these limitations. Preferably, such strategies should not only enhance radiation-induced tumor cell killing and the abrogation of tumor cell clonogenicity, but should also support the stimulation of anti-tumor immune mechanisms – a phenomenon which moved into the center of interest of preclinical and clinical research in radiation oncology within the last decade. The present study focuses on inhibition of heat shock protein 90 (HSP90) whose combination with radiotherapy has previously been reported to exhibit convincing therapeutic synergism in different preclinical cancer models. By employing in vitro and in vivo analyses, we examined if this therapeutic synergism also applies to the priming of anti-tumor immune mechanisms in model systems of CRC. Our results indicate that the combination of HSP90 inhibitor treatment and ionizing irradiation induced apoptosis in colorectal cancer cells with accelerated transit into secondary necrosis in a hyperactive Kras-dependent manner. During secondary necrosis, dying cancer cells released different classes of damage-associated molecular patterns (DAMPs) that stimulated migration and recruitment of monocytic cells in vitro and in vivo. Additionally, these dying cancer cell-derived DAMPs enforced the differentiation of a monocyte-derived antigen presenting cell (APC) phenotype which potently triggered the priming of allogeneic T cell responses in vitro. In summary, HSP90 inhibition – apart from its radiosensitizing potential – obviously enables and supports the initial steps of anti-tumor immune priming upon radiotherapy and thus represents a promising partner for combined modality approaches. The therapeutic performance of such strategies requires further in-depth analyses, especially for but not only limited to CRC
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