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Írásunkban két végén befogott, vékony (100 μm-nél vékonyabb) lemezek egyirányú húzás hatására bekövetkező ráncosodását vizsgáljuk. Az irodalomban széles körben használt, infinitezimális nyúlásokon alapuló Kármán Tódor-féle nagy lehajlású, vékony lemezek elmélete a nyújtás egy kritikus értéke felett a ráncos mintázat stabilitását jósolja, függetlenül a további nyújtás mértékétől. Numerikus szimulációk alapján a ráncos mintázat korlátlan stabilitása nem igazolható akkor, ha az elméleti levezetés (összhangban a terheléssel) véges nyúlásokat is megenged. Ez utóbbi modellben a triviális, síkbeli megoldás egy második bifurkációs pontban visszanyeri stabilitását. Jelen írás célja ezen előrejelzés kísérleti igazolása polipropilén szalagok elmozdulás-vezérelt nyújtásával. A kísérletekből meghatározott elágazási pontoknak a paramétertérben elfoglalt helye jó egyezést mutat a kiterjesztett elméleten alapuló, a nemlineáris végeselem-módszert a Newton-Raphson-módszerrel ötvöző algoritmus eredményeivel.

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Abstract

Recently it became increasingly evident that the statistical distributions of size and shape descriptors of sedimentary particles reveal crucial information on their evolution and may even carry the fingerprints of their provenance as fragments. However, to unlock this trove of information, measurement of traditional geophysical shape descriptors (mostly detectable on 2D projections) is not sufficient; fully spherical 3D imaging and mathematical algorithms suitable to extract new types of inherently 3D shape descriptors are necessary. Available 3D imaging technologies force users to choose either speed or full sphericity. Only partial morphological information can be extracted in the absence of the latter (e.g., LIDAR imaging). In the case of fully spherical imaging, speed was proved to be prohibitive for obtaining meaningful statistical samples, and inherently 3D shape descriptors were not extracted. Here we present a new method by complementing a commercial, portable 3D scanner with simple hardware to quickly obtain fully spherical 3D datasets from large collections of sedimentary particles. We also present software for the automated extraction of 3D shapes and automated measurement of inherently 3D-shape properties. This technique allows for examining large samples without the need for transportation or storage of the samples, and it may also facilitate the collaboration of geographically distant research groups. We validated our software on a large sample of pebbles by comparing previously hand-measured parameters with the results of automated shape analysis. We also tested our hardware and software tools on a large pebble sample in Kawakawa Bay, New Zealand.

Open access

Optimal Layout of Modular Systems by Geometric Perturbations

Moduláris rendszerek optimális kiosztása geometriai perturbációk segítségével

Építés - Építészettudomány
Authors:
Nikolett Domonkos
,
Júlia Zita Martinek
, and
Eszter Fehér

In this study, we investigate the potential of integrating geometric perturbations into the design process to optimise modular systems such as floor coverings, façade claddings, and masonry walls. By allowing small geometry adjustments of the initial design, we achieve significant reductions in material waste or labour requirements, leading to cost-saving and environmental benefits without compromising the design concept. We compared our approach to traditional methods, where the layout of the modular system is determined after the geometry of the design is finalised. To illustrate our method, we present case studies for two- and three-dimensional modular designs.

Open access
Hungarian Medical Journal
Authors:
Krisztina Hagymási
,
Gabriella Lengyel
,
Eszter Nagy
,
Zsolt Pallai
,
Ibolya Kocsis
,
János Fehér
,
Zsolt Tulassay
, and
Anna Blázovics

Non-alcoholic fatty liver disease (NAFLD) is developed mainly by insulin resistance and oxidative stress, but the exact pathogenesis is unknown. Increased prevalence of non-organ specific autoantibodies (NOSA) in NAFLD may be the result of primary immune-mediated mechanism or secondary hepatocellular injury as a consequence of free radical reaction and cytokine production. The importance of NOSA positivity in NAFLD is uncertain. Our aim was to investigate the NOSA prevalence and the redox status as well as the cytokine level in NAFLD patients. Plasma free SH-group concentration, total antioxidant status were measured by colorimetric methods. Free radical–antioxidant balance was determined by a chemiluminometric assay. IL-6 concentration was measured by ELISA in various group of NAFLD patients. NOSA (antinuclear antibody) prevalence was found to be 55% in NAFLD patients. NOSA-positive patients showed a decrease of plasma free SH-group concentration, total antioxidant status and strengthening of free radical reaction. Elevated IL-6 concentrations were measured in both patient groups, but IL-6 concentration was higher in the ANA-negative group with better antioxidant status.

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Primer vena cava inferior leiomyosarcoma (VCI-LMS) sebészi kezelése

Surgical treatment of primary leiomyosarcoma of the inferior vena cava

Magyar Sebészet
Authors:
Zoltán József Biró
,
Károly Kalmár Nagy
,
Eszter Fehér
,
Éva Gömöri
, and
Örs Péter Horváth

Absztrakt

Esetismertetés: Ismertetjük egy fiatal nőbeteg rendkívül ritka retroperitonealis daganatának, a vena cava inferior primer leiomyosarcomájának (VCI-LMS) tünettanát, diagnosztikáját, valamint sebészi kezelését. Műtét során derült fény a VCI középső szegmensének falából kiinduló, jelentős méretű malignitásra, amelyet cavaresectióval és szintetikusgraft-pótlással lehetett rekonstruálni. 8 évvel később recidíva miatt újabb műtétre került sor, azonban a bal v. renalis érintettsége komoly műtéttechnikai problémákat vetett fel. Újabb cavaresectio és graftpótlásos v. renalis reimplantáció történt. A beteg szövődménymentesen távozott otthonába. Megbeszélés: A VCI-LMS egy rendkívül ritka sebész-patológiai entitás, mely a vénafal mediájából kiindulva terjedhet intraluminalisan, extraluminalisan vagy mindkét irányba egyaránt. Lokalizációjától függően, amennyiben az 1. szegmensben (vv. hepaticae fölött), a 2. szegmensben (vv. renales és vv. hepaticae között) vagy a 3. szegmensben (vv. renales és v. iliaca között) található, kapcsolatban lehet a máj, illetve a vese venáival, azokat infiltrálva. Tünettanilag a felső szegmens tumora a Budd–Chiari-tünetegyüttes (hepatomegalia, hasi fájdalom, sárgaság, ascites) mellett rendkívül rossz prognózisú, míg a középső lokalizációjú jobb felhasi fájdalom mellett epeúti megbetegedés képét utánozza, és jelentősen jobb hosszú távú kimenetellel bír. A tapasztalat azt mutatja, hogy a radio-kemoterápia ezen daganat kezelésében nem járható út. A radikális ‘en bloc’-resectio tumormentes szélek biztosításával, majd az érintett szakasz rekonstrukciója jelenti az egyetlen adekvát kezelési módot.

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Abstract

Nutritional information on packaging is becoming increasingly important in the food industry. Currently, labels are seen not only on the back of the packaging but also on the front. As there are many versions of front-of-pack labels (FoPLs), the research aims to determine which helps consumers the most in making decisions about which food to include in a healthier lifestyle. Nutri-Score, Guideline Daily Amount (GDA) and Multiple Traffic Lights (MTL) FoPLs on cereals were compared using eye-tracking (ET) and choice-based conjoint analysis (CBCA). CBCA was used to assess consumer preferences and the labels and products were also ranked. Based on the results, GDA type FoPL proved to be the most useful based on conjoint analysis, ranking and the analysis of ET parameters. This label helped participants the most in choosing the product that best fits into a healthier lifestyle. The Nutri-Score label, which offers little information on a product's nutritional content, was not favourably received by the Hungarian sample, who preferred more detailed FoP labels.

Open access
Central European Geology
Authors:
Zoltán Kern
,
Mátyás Árvai
,
Petru Urdea
,
Fabian Timofte
,
Eszter Antalfi
,
Sándor Fehér
,
Tamás Bartyik
, and
György Sipos

Abstract

Visiting three gravel pits and three natural outcrops across the Mureş/Maros Alluvial Fan, 58 samples were collected from subfossil driftwood recovered from coarse-grained fluvial sediment layers, while no subfossil wood was found at three additional gravel pits. Dendrochronological and radiocarbon analysis of these relict wood can support the temporal extension of the regional dendrochronological reference datasets and their dating can provide a useful contribution to the reconstruction of the landscape evolution of the Mureş/Maros Alluvial Fan. The tree-ring widths of the subfossil samples were measured. Dendrochronological synchronization resulted in two oak chronologies which encompassed five, and two reliably cross-dated series covering 191 years (MURchr1) and 127 years (MURchr2), respectively. Based on the 14C ages the subfossil driftwood material represents Middle and Late Holocene ages. The occasionally up to 6 m-thick fluvial sediment covering relatively young, < 1000-yr-old wood, indicates intense accumulation at the apex of the Mureş/Maros Alluvial Fan, which explains the documented rapid and significant Holocene avulsions.

Open access