179 research outputs found

    Mechanical Properties of Coronary Veins

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    There are several publications available and experiments were done regarding to the vessel biomechanical properties. In the range we could find in vitro and in vivo assessments data for elasticity properties. Even though we have many results in this topic we still don’t have enough data for special veins. Three coronary veins were investigated from pig’s heart. The aim of these experiments was to define and measure the longitudinal tensile stress and tensile strength of coronary veins. The tensile tests were done successfully and the tensile stress was defined in the range of 1.66-2.57 MPa

    Amplitude Modulation in the ZZ Ceti Star GD 244

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    Previous studies of GD 244 revealed seven pulsation frequencies (two doublets and three single periods) in the light variations of the star. The data obtained at McDonald Observatory between 2003 and 2006, and our additional measurements in 2006 and 2007 at Konkoly Observatory, allow the investigation of the long-term pulsational behaviour of GD 244. We found that the 307.1 s period component of one of the doublets show long-term, periodic amplitude modulation with a time scale of ~740 days. Possible explanations are that nonlinear resonant mode coupling is operating among the rotationally split frequency components, or two modes, unresolved in the yearly data are excited at ~307.1 s. This is the first time that such long-term periodic amplitude modulation is published on a ZZ Ceti star.Comment: 4 pages, 2 figures, appeared in ASP Conference Series vol. 493, 2015 (eds.: P. Dufour, P. Bergeron, G. Fontaine, 19th European Workshop on White Dwarfs, Montreal, Canada

    G 207-9 and LP 133-144: light curve analysis and asteroseismology of two ZZ Ceti stars

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    G 207-9 and LP 133-144 are two rarely observed ZZ Ceti stars located in the middle and close to the blue edge of the ZZ Ceti instability domain, respectively. We aimed to observe them at least during one observing season at Konkoly Observatory with the purpose of extending the list of known pulsation modes for asteroseismic investigations and detect any significant changes in their pulsational behaviour. We determined five and three new normal modes of G 207-9 and LP 133-144, respectively. In LP 133-144, our frequency analysis also revealed that at least at three modes there are actually triplets with frequency separations of ~4 microHz. The rotational period of LP 133-144 based on the triplets is ~42 h. The preliminary asteroseismic fits of G 207-9 predict Teff=12 000 or 12 400 K and M*=0.855-0.870 MSun values for the effective temperature and mass of the star, depending on the assumptions on the spherical degree (l) values of the modes. These results are in agreement with the spectroscopic determinations. In the case of LP 133-144, the best-fitting models prefer Teff=11 800 K in effective temperature and M*>=0.71 MSun stellar masses, which are more than 0.1 MSun larger than the spectroscopic value.Comment: 12 pages, 11 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society (2016 June 30

    More frequencies of KUV 02464+3239

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    Preliminary results on KUV 02464+3239, a pulsating DA white dwarf are presented. Located near the red edge of the DAV instability strip, KUV 02464+3239 shows large amplitude and long period pulsation modes. Up to now only one mode was known from a 50-minute-long light curve. Our more extended observations allowed the identification of three additional frequencies. The presence of previously known harmonics were confirmed and weak subharmonics are also noticeable at some parts of the light curve. This suggests the dominance of nonlinear pulsation effects from time to time.Comment: 3 pages, 3 eps figures; has been accepted for publication in Astronomische Nachrichten (Vol. 8, 2007), proceedings of the British-Hungarian-French N+N+N Workshop for Young Researcher

    Formation of 3-Monochloro-1,2-Propanediol Fatty Acid Esters During Deep-Fat Frying of Pre-Fried Deep Frozen Food with Different Salt Content

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    Changes of edible oil quality factors and formation of 3-monochloro-1,2-propanediol fatty acid esters (3-MCPD-FE) during deep-fat frying in four different experiments (control, salt, pork chop, and chicken liver) with high oleic sunflower oil were compared in this study. Based on the results of investigated oil quality parameters, which were free fatty acid (FFA), anisidine value (AV), UV extinction at 232 and 268 nm (E232 and E268, respectively), and total polar material (TPM), only a modest deterioration of the frying oil was observed. As we expected, the 3-MCPD-FE content in the control samples did not reach the limit of quantification (0.1 mg kg–1), while the table salt itself caused a slight increase. The results of pork chop and chicken liver experiments were not statistically different from each other, after the third frying circle 0.52 and 0.39 mg kg–1 3-MCPD-FE levels were reached, respectively. Based on these values, the human exposure estimation resulted in a low risk

    Expression of invasion-related extracellular matrix molecules in human glioblastoma versus intracerebral lung adenocarcinoma metastasis

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    Tumor cell invasion into the surrounding brain tissue is mainly responsible for the failure of radical surgical resection, with tumor recurrence in the form of microdisseminated disease. Extracellular matrix (ECM)-related molecules and their receptors predominantly participate in the invasion process, including cell adhesion to the surrounding microenvironment and cell migration. The extent of infiltration of the healthy brain by malignant tumors strongly depends on the tumor cell type. Malignant gliomas show much more intensive peritumoral invasion than do metastatic tumors. In this study, the mRNA expression of 30 invasion-related molecules (twenty-one ECM components, two related receptors, and seven ECM-related enzymes) was investigated by quantitative reverse transcriptase-polymerase chain reaction. Fresh frozen human tissue samples from glioblastoma (GBM), intracerebral lung adenocarcinoma metastasis, and normal brain were evaluated. Significant differences were established for 24 of the 30 molecules. To confirm our results at the protein level, immunohistochemical analysis of seven molecules was performed (agrin, neurocan, syndecan, versican, matrix metalloproteinase 2 [MMP-2], MMP-9, and hyaluronan). Determining the differences in the levels of invasion-related molecules for tumors of different origins can help to identify the exact molecular mechanisms that facilitate peritumoral infiltration by glioblastoma cells. These results should allow the selection of target molecules for potential chemotherapeutic agents directed against highly invasive malignant gliomas

    Investigation of the mechanical and chemical characteristics of nanotubular and nano-pitted anodic films on grade 2 titanium dental implant materials

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    Abstract Objective The objective of this study was to investigate the reproducibility, mechanical integrity, surface characteristics and corrosion behavior of nanotubular (NT) titanium oxide arrays in comparison with a novel nano-pitted (NP) anodic film. Methods Surface treatment processes were developed to grow homogenous NT and NP anodic films on the surface of grade 2 titanium discs and dental implants. The effect of process parameters on the surface characteristics and reproducibility of the anodic films was investigated and optimized. The mechanical integrity of the NT and NP anodic films were investigated by scanning electron microscopy, surface roughness measurement, scratch resistance and screwing tests, while the chemical and physicochemical properties were investigated in corrosion tests, contact angle measurement and X-ray photoelectron spectroscopy (XPS). Results and discussion The growth of NT anodic films was highly affected by process parameters, especially by temperature, and they were apt to corrosion and exfoliation. In contrast, the anodic growth of NP film showed high reproducibility even on the surface of 3-dimensional screw dental implants and they did not show signs of corrosion and exfoliation. The underlying reason of the difference in the tendency for exfoliation of the NT and NP anodic films is unclear; however the XPS analysis revealed fluorine dopants in a magnitude larger concentration on NT anodic film than on NP surface, which was identified as a possible causative. Concerning other surface characteristics that are supposed to affect the biological behavior of titanium implants, surface roughness values were found to be similar, whereas considerable differences were revealed in the wettability of the NT and NP anodic films. Conclusion Our findings suggest that the applicability of NT anodic films on the surface of titanium bone implants may be limited because of mechanical considerations. In contrast, it is worth to consider the applicability of nano-pitted anodic films over nanotubular arrays for the enhancement of the biological properties of titanium implants

    Predictive factors for response to neoadjuvant therapy in patients with oesophageal cancer

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    Background: Preoperative radio-chemotherapy (RCX) was introduced to improve the outcome of patients with oesophageal cancer (EC), but conflicting results have been released. Some 20-30% of patients show a complete pathological response, however, the perioperative morbidity and mortality is increased. To search for factors indicating response prior to the onset of RCX we investigated the proliferative activity (MIB-1), the expression of vascular endothelial growth factor (VEGF), and the capillary density (CD34) in samples of EC obtained by endoscopy prior to the start of the treatment. Methods: Forty-six (MIB-1) and 21 (VEGF, CD34) tissue specimens of ECs were available from 56 patients undergoing pretherapeutic endoscopy, RCX and surgery. Perioperative morbidity was divided into surgery and non-surgery related morbidity. MIB-1, VEGF and CD34 expression were investigated immunohistochemically. Multivariate analysis was carried out to prove independence of investigated variables. Results: Postoperative morbidity was noticed in 54 of 56 operated patients. Eight of 56 patients who received RCX died in hospital. Survival was significantly different between the group of complete responders (n=14) and non-responders (n=23; P=0.0026). None of the investigated tumour samples from patients with a complete response (CR) had a proliferation index of less than 45. Tumour samples from patients with a CR showed a VEGF expression of 10.7 compared with 36.58 of tumours with no response (P=0.035). CD34 expression showed a correlation with VEGF expression. The relation of mean indices of VEGF expression and proliferative activity in tumours from patients with complete, partial or no response was 10.7:58.8, 18.3:53.8 and 36.6:43.5, respectively. Conclusions: According to these results, it may be expected that tumours with a VEGF/MIB-1 ratio of 1:6 or less prior to RCX will respond to this therapy. Copyright © 2002 Elsevier Science B.V
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