The Effect of Fatigue Test on the Mechanical Properties of the Cellular Polyurethane Mats Used in Tram and Railway Tracks

The use of modern synthetic materials is an important element in the development of railway tracks. Their use is a response to the growing requirements regarding the durability of structures and environmental protection against traffic noise and vibrations. In this paper, the results of the laboratory tests of selected mechanical properties of cellular polyurethane (PUR) mats which are applied in tram and railway tracks are presented in this study. The aim of the research was to determine the effect of fatigue loading on the mechanical performance of polyurethane mats. A series of samples made of two types of materials with different pore structures were tested. Static and fatigue laboratory tests were carried out on a specially prepared test stand. The values of selected mechanical parameters (the vertical static bedding modulus, the vertical dynamic bedding modulus, and the loss factor) were evaluated. The results of laboratory tests and analyses showed a significant influence of high-cycle fatigue loading on the values of mechanical parameters of the tested mats, which were quantified as a result of the study. For both types of materials, the phenomenon of cyclic hardening was observed. Additionally, for one of the materials, an undesired dynamic creep phenomenon was observed. It was also shown that the pore structure of polyurethane influences the mechanical performance of the mats. Therefore, the findings of the research may have practical significance for the quality evaluation of such materials, especially in the context of their durability and mechanical stability under real loading conditions.     

On Incipient Plasticity of InP Crystal: A Molecular Dynamics Study

With classical molecular dynamics simulations, we demonstrated that doping of the InP crystal with Zn and S atoms reduces the pressure of the B3→B1 phase transformation as well as inhibits the development of a dislocation structure. On this basis, we propose a method for determining the phenomenon that initiates nanoscale plasticity in semiconductors. When applied to the outcomes of nanoindentation experiments, it predicts the dislocation origin of the elastic-plastic transition in InP crystal and the phase transformation origin of GaAs incipient plasticity.     

MT103 inhibits tumor growth with minimal toxicity in murine model of lung carcinoma via induction of apoptosis

Molecular topology (MT) was used to develop quantitative structure-activity relationship (QSAR) models to screen databases for new anticancer compounds. One of the selected compounds was MT103, an isoborneol derivative, with a promising profile predicted to slow tumor growth through pro-apoptotic signaling and protein kinase C inhibition. We found that MT103 inhibited the growth of a wide variety of cancer cell types as verified by the NCI-60 cancer cell line panel. MTT cell viability assay showed that MT103 inhibited 50% of the growth of HOP-92, ACHN, NCI-H226, MCF-7, and A549 cancer cell lines at much lower concentrations than that required for HUVECs and human fibroblasts. MT103 stimulated apoptosis in NCI-H226 lung carcinoma cells as measured by oligonucleosomal DNA fragmentation. However, protein kinase C was not targeted by MT103, as predicted by in silico modeling. MT103 slowed in vivo tumor growth and metastatic spread of NCI-H226 cells injected subcutaneously into NOD/SCID mice, without eliciting any severe adverse events as monitored by animal survival, blood serum analysis, and histological analysis of organs. Oral administration of MT103 nanoparticles (200 nm in diameter), which were generated with ElectroNanospray™ technology, inhibited in vivo growth of HOP-92 lung carcinoma cells almost as effectively as intraperitoneal injections of cisplatin. Taken together, our study of a novel anti-cancer drug identified using a molecular topology-based approach to drug discovery demonstrates that MT103 has anti-tumor activity in vitro and in vivo, although additional studies are needed to elucidate its mechanism of action.     

Multispecies animal investigation on biodistribution,pharmacokinetics and toxicity of 177Lu-EDTMP,a potential bone pain palliation agent

IntroductionRadionuclide therapy (RNT) is an effective method for bone pain palliation in patients suffering from bone metastasis. Due to the long half-life, easy production and relatively low β? energy, ¹⁷⁷Lu [T_1/2=6.73 days, E_βmax=497 keV, E_γ=113 keV (6.4%), 208 keV (11%)]-based radiopharmaceuticals offer logistical advantage for wider use. This paper reports the results of a multispecies biodistribution and toxicity studies of ¹⁷⁷Lu-EDTMP to collect preclinical data for starting human clinical trials.Methods¹⁷⁷Lu-EDTMP with radiochemical purity greater than 99% was formulated by using a lyophilized kit of EDTMP (35 mg of EDTMP, 5.72 g of CaO and 14.1 mg of NaOH). Biodistribution studies were conducted in mice and rabbits. Small animal imaging was performed using NanoSPECT/CT (Mediso, Ltd., Hungary) and digital autoradiography. Gamma camera imaging was done in rabbits and dogs. Four levels of activity (9.25 through 37 MBq/kg body weight) of ¹⁷⁷Lu-EDTMP were injected in four groups of three dogs each to study the toxicological effects.Results¹⁷⁷Lu-EDTMP accumulated almost exclusively in the skeletal system (peak ca. 41% of the injected activity in bone with terminal elimination half-life of 2130 and 1870 h in mice and rabbits, respectively) with a peak uptake during 1–3 h. Excretion of the radiopharmaceutical was through the urinary system. Imaging studies showed that all species (mouse, rat, rabbit and dog) take up the compound in regions of remodeling bone, while kidney retention is not visible after 1 day postinjection (pi). In dogs, the highest applied activity (37 MBq/kg body weight) led to a moderate decrease in platelet concentration (mean, 160 g/L) at 1 week pi with no toxicity.ConclusionThe protracted effective half-life of ¹⁷⁷Lu-EDTMP in bone supports that modifying the EDTMP molecule by introducing ¹⁷⁷Lu does not alter its biological behaviour as a specific bone-seeking tracer. Species-specific pharmacokinetic behavior differences were observed. Toxicity studies in dogs did not show any biological adverse effects. The studies demonstrate that ¹⁷⁷Lu-EDTMP is a promising radiopharmaceutical that can be further evaluated for establishing as a radiopharmaceutical for human use.     

A cross‐validation procedure for general pedigrees and matched odds ratio fitness metric implemented for the multifactor dimensionality reduction pedigree disequilibrium test

As genetic epidemiology looks beyond mapping single disease susceptibility loci, interest in detecting epistatic interactions between genes has grown. The dimensionality and comparisons required to search the epistatic space and the inference for a significant result pose challenges for testing epistatic disease models. The multifactor dimensionality reduction–pedigree disequilibrium test (MDR‐PDT) was developed to test for multilocus models in pedigree data. In the present study we rigorously tested MDR‐PDT with new cross‐validation (CV) (both 5‐ and 10‐fold) and omnibus model selection algorithms by simulating a range of heritabilities, odds ratios, minor allele frequencies, sample sizes, and numbers of interacting loci. Power was evaluated using 100, 500, and 1,000 families, with minor allele frequencies 0.2 and 0.4 and broad‐sense heritabilities of 0.005, 0.01, 0.03, 0.05, and 0.1 for 2‐ and 3‐locus purely epistatic penetrance models. We also compared the prediction error (PE) measure of effect with a predicted matched odds ratio (MOR) for final model selection and testing. We report that the CV procedure is valid with the permutation test, MDR‐PDT performs similarly with 5‐ and 10‐fold CV, and that the MOR is more powerful than PE as the fitness metric for MDR‐PDT. Genet. Epidemiol. 34: 194–199, 2010. © 2009 Wiley‐Liss, Inc.     

Giant saccular superior vena cava aneurysm—a rare and difficult clinical case

A superior vena cava (SVC) aneurysm is an extremely rare case of vascular malformation in the chest cavity. This is a report of a case of a 57-year-old woman with a saccular SVC aneurysm which was 8 cm wide. The chest computed tomography (CT) scan confirmed a giant 75 mm × 79 mm × 81 mm mass containing the contrast medium from SVC, constricting the right lung parenchyma, narrowing the right innominate vein, in contact with the anterolateral chest cavity wall, and adjoining the superior mediastinum. Under general anesthesia and employing the median sternotomy approach, using a cardiopulmonary bypass (CPB), the venous aneurysm was successfully resected. The postoperative period was uneventful. Radical surgical resection using a sternotomy and a CPB is recommended.     

"Tombstoning" of ST segment in acute myocardial infarction -- effect on clinical course

INTRODUCTION: There are many reports evaluating the effects of the amplitude of ST segment elevation in acute myocardial infarction with ST segment elevation (STEMI) on infarction zone and course. There are, however, few publications dealing with the effects of ST segment elevation shape in STEMI patients on their clinical course and prognosis. AIM: Assessment of the rate of "tombstoning" of ST segment (TOMB-ST) in STEMI patients and the effects on their clinical outcome. METHODS: The study involved 207 consecutive patients with STEMI hospitalised in the period 2000-2002 analysed with respect to the in-hospital complication rate. RESULTS: On admission, TOMB-ST was observed in 55 (26.1%) subjects. TOMB-ST was more common in anterior MI (39.8%) than in inferior MI (10.6%). Patients with TOMB-ST compared to non-TOMB-ST ones had a significantly higher mortality rate (38.2% vs 9.9%, p <0.001), heart failure (45.6% vs 28.3%, p <0.026), ventricular fibrillation (18.1% vs 6.4%, p <0.016), and lower left ventricular ejection fraction (40.9% vs 48.6%, p <0.001). The sum of amplitudes of ST segment deviations (SigmaST) >20 mm was indicative for the subgroup of patients with TOMB-ST and trend towards higher mortality (40% vs 30%, NS). However, in patients without TOMB-ST, SigmaST >20 mm identified two subgroups with significantly different mortality rates (20% vs 4%, p=0.001). CONCLUSIONS: TOMB-ST was observed in one fourth of patients with STEMI. This abnormality was associated with an increased mortality rate, higher incidence of heart failure and ventricular fibrillation as well as decreased left ventricular ejection fraction. In the population with TOMB-ST, increased mortality was independent of the total amplitude of ST segment displacement; this relation was, however, observed in patients with STEMI without TOMB-ST.     

Stenting of unprotected left main coronary artery in patients with low preoperative risk of coronary artery bypass grafting

INTRODUCTION: Available data indicate that stenting of the left main coronary artery (LMN) is safe and effective. Restenosis remains the main factor limiting the effectiveness of percutaneous coronary intervention (PCI). AIM: To evaluate immediate and long-term results of treatment of patients with LMN disease and low preoperative risk of coronary artery bypass grafting. METHODS: Coronary stents were implanted into LMN in 64 patients. The following strategy was applied: drug eluting stent (DES) for LMN diameter < or =3.5 mm (28 subjects) and bare metal stent (BMS) for LMN diameter >3.5 mm (36 subjects). Patients enrolled in the study underwent clinical evaluation and coronary angiography. Immediate effect of the procedure and main adverse cardiac events were assessed: death, myocardial infarction and additional target lesion or non-target lesion revascularization. RESULTS: Angiographic and clinical effectiveness of the interventions was 100%. Full revascularisation of ischaemic regions of the myocardium was performed. Mean clinical follow-up period was 9.4+/-4.0 months. Neither death nor myocardial infarction occurred. Additional PCIs were performed in 11 (17.2%) patients; however, target vessel revascularisation (TVR) rate within LMN was 9.4% (i.e. 6 subjects with BMS), and non-TVR rate was 7.8% (5 subjects). CONCLUSIONS: LMN stenting is associated with high effectiveness of PCI in patients with low operative risk. Long-term follow-up revealed low incidence of major adverse cardiac events. Strategy of selective use of DESs in the study group produced good clinical outcome. Multivessel disease with LMN stenosis was associated with high rate of additional revascularisation of other vessels. Further improvement of treatment results may be obtained by more common use of DES for multivessel disease and LMN diameters larger than 4.0 mm.