189 research outputs found

    A Comparative Evaluation of Predictive Models of the Flat Rolling Process

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    The predictive abilities of several mathematical models of the cold, flat rolling process are tested by comparing their predictions to experimental measurements. The models include an empirical model, a one-dimensional model, a finite element model and an upper bound model. The coefficient of friction and the friction factor are first determined by the inverse approach, using the model deemed to be the most comprehensive. The effects of including or excluding an account of roll flattening, using elastic-plastic or rigid-plastic strips, and constant or velocity dependent coefficients of friction or friction factors are examined

    Investigation of Possibilities of λ = 1 Full Load Operation for Gasoline Engines in the Light of Future Emission Regulation

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    To date, huge amounts of money have been invested in the development of internal combustion engines to reach the current level of technology. High specific power and good thermal efficiency have been achieved, thanks to which, internal combustion engines are now widely used. However, the driving force behind the developments is no longer the high performance, but the compliance with strict emission standards. Future emissions regulation, namely Euro 7, will be challenging for engine and vehicle manufacturers. One possible technical solution may be to use a stoichiometric air-fuel mixture on the entire engine map to meet the requirements of the Euro 7 emission standard. This article analyzes the change in Euro regulations in the light of Euro 7, as well as the theoretical background of the λ = 1 operation. Several technical possibilities to achieve the stoichiometric ratio, such as e.g. water injection or variable compression ratio are presented

    Antirheumatic drugs and cardiovascular disease in rheumatoid arthritis

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    There is increased cardiovascular (CV) morbidity and mortality in rheumatoid arthritis (RA) and other rheumatic and musculoskeletal diseases (RMDs). Systemic inflammation is highly involved in atherogenesis. Non-steroidal anti-inflammatory drugs (NSAIDs), primarily COX-2 inhibitors might increase CV risk. Corticosteroids might act as a double-edged sword as they exert both beneficial and negative effectson the CV system. NSAIDs and corticosteroids are anti-inflammatory, but, on the other hand, they might be potentially atherogenic. Conventional synthetic DMARDs (csDMARDs), such as antimalarials, methotrexate, sulfasalazine, leflunomide and cyclosporine A have good CV safety, however, leflunomide and cyclosporine A might cause hypertension. Biologic DMARDs, by suppressing inflammation and disease activity, might either reduce CV risk or at least not cause any harm in that respect. Recently, tofacitinib and most likely other Janus kinase inhibitors have been associated with increased CV risk, at least in RMD patients with high CV risk at baseline. In clinical practice, EULAR and other recommendations guide the rheumatologist when screening for and managing CV comorbidities

    Identification of myoelectric signals of pregnant rat uterus: new method to detect myometrial contraction

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    Aim To develop an electromyography method for pregnant rat uterus in vivo and to separate myometrial signals from the gastrointestinal tract signals. Methods: Pregnant Sprague-Dawley rats (n = 8) were anaesthetized and their stomach, small intestine, and large intestine were removed from the abdomen. A pair of thread electrodes was inserted into the uterus, while a pair of disk electrodes was placed subcutaneously above the myometrium. Additionally, a strain gauge sensor was fixed on the surface of the myometrium and cecum for the parallel detection of mechanical contractions in rats (n = 18) with intact gastrointestinal tract. The filtered electric signals were amplified and recorded by an online computer system and analyzed by fast Fourier transformation. The frequency of the electric activity was characterized by cycle per minute (cpm), the magnitude of the activity was described as power spectrum density maximum (PsDmax). Results: The frequency of the pregnant uterine activity was 1-3 cpm, which falls within the same range as that of cecum. Measuring by both electrodes, oxytocin (1 μg/kg) increased and terbutaline (50 μg/kg) decreased the PsDmax by 25%-50% (P < 0.001) and 25%-40% (P < 0.01), respectively. We found a strong positive correlation between the alterations of PsDmax values and the strain gauge sensordetected mechanical contractions (area under curve). The GI specific compounds (neostigmine, atropine) mainly affected the cecal activity, while myometrium specific drugs (oxytocin, terbutaline) influenced the myometrial signals only. Conclusion: Our method proved to be able to detect the myoelectric activity that reflects the mechanical contraction. The overlapping myometrial and cecal signals are not separable, but they can be distinguished based on the much higher activity and different pharmacological reactivity of the pregnant uterus. Thus, the early signs of contractions can be detected and labor may be predicted in a fast and sensitive way

    A mozgató működésekért felelős gerincvelői neuronhálózatok morfológiai, fiziológiai vizsgálata és számítógépes szimulációja = Morphological, physiological investigations and computer simulation of spinal neuronal network involved in locomotion.

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    1. Fiziológiai kísérletekben jelentős különbségeket találtak propriospinalis axon - motoneuron (MN) kapcsolatokban a MN-ból elvezetett EPSP amplitúdójában a béka gerincvelőben. Modellkísérletekkel bizonyítottuk, hogy a kapcsolatok között mért eltéréseket több tényező magyarázhatja: a szinapszisok elhelyezkedése, a dendrit kitüremkedések, nem-lineáris PSP szummáció illetve a PSP-ok szómára érkezéséhez szükséges késési idők eltérései. 2. A Xenopus embrió úszómozgásáért felelős központi ritmusgeneráló hálózatában azt vizsgáltuk, hogyan vezethet egy rövid inger hosszú ideig tartó úszó mozgáshoz. Az utóagy-gerincvelő határának populációs modelljében azt találtuk, hogy az utóagyi neuronok közötti reciprok serkentő kapcsolatok felelősek lehetnek az említett jelenségért. Elképzelésünket a kísérletes eredmények megerősítik. 3. Patkány gerincvelőben vizsgáltuk a cink kolokalizációját gátló aminosavakkal. Eredményeink azt mutatták, hogy a gerincvelőben a cink tartalmú terminálisok elsősorban gátló karakterűek, amelyekben a GABA és glicin is megtalálható. 4. Újszülött patkány gerincvelőben elemeztük a commissuralis interneuronok (CIN) neurokémiai sajátságait és szinaptikus kapcsolatait. A jelölt CIN terminálisok több mint fele tartalmazott gátló aminosavat, míg a glutamátot tartalmazó terminálisok aránya 27% volt. A jelölt CIN terminálisok közvetlen kapcsolatot képeztek az ellenoldali motoneuronokkal és CIN-okkal. | 1. We investigated the postsynaptic factors that may contribute the high variability of synaptic efficacy in monosynaptically connected propriospinal axon-motoneuron pairs in the spinal cord of frog. We proved that differences in location of these synapses, dendritic protrusions, non-linear summation of PSPs, sizes of time windows for effective temporal summation and differences in delays of arrivals of PSPs to soma are all factors that may differentiate between high and low efficacy single fiber propriospinal connections found experimentally. 2. The central pattern generator for swimming in the Xenopus tadpole was investigated to find out how a brief stimulus can lead to prolonged swimming. By using large-scale population model of the hindbrain-spinal cord junction we found that reciprocal excitatory connections among hindbrain neurons may be responsible for this phenomenon. Our proposal has strong experimental support. 3. Colocalization of zinc with inhibitory neurotrasmitters was investigated in the rat spinal cord. 70% of zinc-containing terminals showed immunoreactivity for GABA and glycine. 4. In neonatal rats we investigated the axonal projection and neurotransmitter properties of spinal commissural interneurons (CIN). About half of the labelled CIN terminals contained GABA or glycine and one third proved to be excitatory. Many of CIN terminals made close appositions with motor neurons and also with CINs on the opposite side of the spinal cord

    Áttétes vesedaganatos betegek everolimusterápiájával szerzett hazai tapasztalatok

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    Everolimus is indicated for the therapy of adults with advanced renal cell carcinoma after failure of treatment with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI). The aim of the study was a multicenter evaluation of efficiency and toxicity of everolimus in patients with metastatic renal carcinoma who received one line of VEGFR-TKI therapy. Data of one hundred and one patients were analyzed retrospectively. Patients received everolimus therapy between January 2010 and July 2013. Data were collected in 7 different oncology institutes in Hungary. Starting daily dose of everolimus was 10 mg in 28-day cycles. Physical and laboratory examinations were done monthly. Imaging tests were performed every 3 months. Tumor response and toxicity were evaluated according to RECIST 1.0 and NCI CTCAE 3.0, respectively. Statistical analysis was performed with SPPS version 20.0 for Windows. Currently 26 (27%) patients are being treated, 52 (54.1%) patients are alive. Median progression-free survival (PFS) was 5.7 months (95% CI 4.07-7.33). Partial remission, stable disease and progression occurred in 6 (6%), 71 (74%) and 19 (20%) patients, respectively. Median overall survival (OS) was 14.3 months (95% CI 6.99-19.81). PFS and OS results were more favorable in patients with ECOG 0-1. Survival was poorer in case of anemia, while better if PFS was longer than 12 months. In anemic patients with ECOG 0-1 and ECOG 2-3 OS was 30.9 and 7.7 months, respectively (p=0.031). Dose reduction and treatment delay happened in 8 (7.9%) and 12 (11.9%) cases, respectively. The most common side effects were the following: exanthema, edema, stomatitis, pneumonitis, anemia and abnormal kidney-, liver functions, blood sugar and cholesterol levels. According to the Hungarian experience, everolimus can safely be administered. PFS and OS results representing the centers' everyday practice, are similar to the results of the respective subgroups in the registration study
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