4,013 research outputs found
An extension of the satellite monitoring Liberty GPS system for the support requirements of transportation companies
In working out the performance principles introduced into the construction and functionality of a Satellite Monitoring Liberty GPS System for vehicles and its possibilities in offering services that improve the logistical processes for transportation companies
Kinetics of gas emission from aluminosilicates used as a relaxing additive for moulding and core sands
The article presents the results of gas emissions generated during heating of mineral additives â aluminosilicates (perlite ore and vermiculite). The test on a laboratory stand for a 1 g sample at 1 000 °C was carried out. It has been shown, that there is a correlation between the degree of fragmentation and the amount of gas generated. The finest fraction of perlite ore caused a similar quantitative gas emission as ground vermiculite. The presence of additives in molding sands, regardless of the size of fraction, should not affect the formation of casting defects. The addition of perlite ore and vermiculite does not effect the ecological properties of moulding sand
Modular classes of skew algebroid relations
Skew algebroid is a natural generalization of the concept of Lie algebroid.
In this paper, for a skew algebroid E, its modular class mod(E) is defined in
the classical as well as in the supergeometric formulation. It is proved that
there is a homogeneous nowhere-vanishing 1-density on E* which is invariant
with respect to all Hamiltonian vector fields if and only if E is modular, i.e.
mod(E)=0. Further, relative modular class of a subalgebroid is introduced and
studied together with its application to holonomy, as well as modular class of
a skew algebroid relation. These notions provide, in particular, a unified
approach to the concepts of a modular class of a Lie algebroid morphism and
that of a Poisson map.Comment: 20 page
A gastrin transcript expressed in gastrointestinal cancer cells contains an internal ribosome entry site
As the hormone gastrin promotes gastrointestinal (GI) cancer progression by triggering survival pathways, regulation of gastrin expression at the translational level was explored. Sequence within the 5âČ untranslated region of a gastrin transcript expressed in GI cancer cells was investigated, then cloned into a bicistronic vector upstream of firefly luciferase and transfected into a series of GI cancer cell lines. Firefly luciferase activity was measured relative to that of a cap-dependent Renilla luciferase. A gastrin transcript that was different from that described in Ensembl was expressed in GI cancer cells. Its transcription appears to be initiated within the region designated as the gene's first intron. In GI cancer cells transfected with the bicistronic construct, firefly luciferase activity increased 8â15-fold compared with the control vector, and there was a further induction of the signal (up to 25-fold) following exposure of the cells to genotoxic stress or hypoxia, suggesting that the sequence acts as an internal ribosome entry site. These data suggest that the gastrin transcript within GI cancer cells contains an internal ribosome entry site that may allow continued expression of gastrin peptides when normal translational mechanisms are inactive, such as in hypoxia, thereby promoting cancer cell survival
NeĆĄkodljivost kalupnih pjesaka sa bentonitom i svijetleÄim nositeljima ugljika
Procedures have been developed to determine the volume, rate and composition (particularly BTEX: benzene, toluene, ethylbenzene and xylenes and PAHs (polycyclic aromatic hydrocarbons)) of gas evolution from moulds and cores prepared with various binders as a means of harmfulness of moulding sands. The rate of gas evolution from green sands with four different lustrous carbon carrier and BTEX content were determined. The gas evolution rates are highest in the range of about 20 to 30 s after contact with molten metal. In practice during the first 200-250 s the total emission of gases generated in investigated samples occurred. The main emitted component from the BTEX group was benzene.Postupci su razvijeni za odreÄivanje volumena, brzine i sastava (posebice BTEX: benzen, toluen, etilbenzen, xilana) i PAH (policikliÄki automatski hidrokarbonati) plina koji nastaje iz kalupa i jezgri na razliÄitim nosaÄima u teĆŸnji za neĆĄkodljivost kalupnih pijesaka. Brzine nastajanja plina iz pripravljenih pijesaka sa 4 razliÄita svijetleÄa nositelja ugljika i sadrĆŸajem BTEX su odreÄeni. Brzine nastajanja plina su najveÄe u razini 20 do 30 s poslije dodira sa rastopljenim metalom. PraktiÄno, tijekom prvih 200-250 s ostvaruje se ukupna emisija stvorenih plinova u istraĆŸivanim uzorcima. Iz BTEX skupine, benzen je glavna emitirajuÄa komponenta
Observation of epitaxially ordered twinned zinc aluminate ânanobladesâ on c-capphire
We report the observation of a novel nanostructured growth mode of the ceramic spinel zinc aluminate grown on c-sapphire in the form of epitaxially ordered twinned crystallites with pronounced vertically aligned ânanobladesâ on top of these crystallites. The nanostructures are formed on bare c-sapphire substrates using a vapour phase transport method. Electron microscopy images reveal the nanostructure morphology and dimensions and allow direct and indirect observation of the twin boundary location in a number of samples. The nanoblade structure with sharply rising sidewalls gives rise to a distinctive bright contrast in secondary electron images in scanning electron microscopy measurements
Bioluminescence imaging of human embryonic stem cells transplanted in vivo in murine and chick models
Research into the behavior, efficacy, and biosafety of stem cells with a view to clinical transplantation requires the development of noninvasive methods for in vivo imaging of cells transplanted into animal models. This is particularly relevant for human embryonic stem cells (hESCs), because transplantation of undifferentiated hESCs leads to tumor formation. The present study aimed to monitor hESCs in real time when injected in vivo. hESCs were stably transfected to express luciferase, and luciferase expression was clearly detected in the undifferentiated and differentiated state. When transfected hESCs were injected into chick embryos, bioluminescence could be detected both ex and in ovo. In the SCID mouse model, undifferentiated hESCs were detectable after injection either into the muscle layer of the peritoneum or the kidney capsule. Tumors became detectable between days 10-30, with approximately a 3 log increase in the luminescence signal by day 75. The growth phase occurred earlier in the kidney capsule and then reached a plateau, whilst tumors in the peritoneal wall grew steadily throughout the period analysed. These results show the widespread utility of bioluminescent for in vivo imaging of hESCs in a variety of model systems for preclinical research into regenerative medicine and cancer biology. © Copyright 2009, Mary Ann Liebert, Inc
Synthesis of Passerini-3CR Polymers and Assembly into Cytocompatible Polymersomes
The versatility of the Passerini three component reaction (Passeriniâ3CR) is herein exploited for the synthesis of an amphiphilic diblock copolymer, which selfâassembles into polymersomes. Carboxyâfunctionalized poly(ethylene glycol) methyl ether is reacted with ABâtype bifunctional monomers and tertâbutyl isocyanide in a single process via Passeriniâ3CR. The resultant diblock copolymer (P1) is obtained in good yield and molar mass dispersity and is well tolerated in model cell lines. The Passeriniâ3CR versatility and reproducibility are shown by the synthesis of P2, P3, and P4 copolymers. The ability of the Passerini P1 polymersomes to incorporate hydrophilic molecules is verified by loading doxorubicin hydrochloride in P1DOX polymersomes. The flexibility of the synthesis is further demonstrated by simple postâfunctionalization with a dye, Cyanineâ5 (Cy5). The obtained P1âCy5 polymersomes rapidly internalize in 2D cell monolayers and penetrate deep into 3D spheroids of MDAâMBâ231 tripleânegative breast cancer cells. P1âCy5 polymersomes injected systemically in healthy mice are well tolerated and no visible adverse effects are seen under the conditions tested. These data demonstrate that new, biodegradable, biocompatible polymersomes having properties suitable for future use in drug delivery can be easily synthesized by the Passeriniâ3CR
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