Szintetikus és NMR kutatások peptidek és szénhidrátok körében = Synthetic and NMR studies of peptides and carbohydrates

Egy immunomoduláns peptidoglikán-monomer (PGM) lipofil származékainak konformációját 2D NMR és molekulamodellezés segítségével határoztuk meg. A szubsztituensek okozta konformáció változások a biológiai aktivitást nem befolyásolják. Bakteriális endotoxinokat (LPS) gátló LALF-14 hexadekapeptid LPS-kötődését hasonló módszerekkel vizsgálva kimutattuk, hogy a teljes LALF protein lipid-A-kötő ?-lemez régiója nem előfeltétele a LALF-14 - LPS-kötődésnek. Dodekapeptidekben NOE-mérésekkel és molekulamodellezéssel aromás gyűrű - amid-H kölcsönhatásokat mutattunk ki amelyek a helikális térszerkezettel kapcsolatosak. Új típusú, háromkötéses glikozidos hidat tartalmazó glikomimetikumok első képviselőiként glikozil-diszulfidokat és -szulfénamidokat szintetizáltunk. Hidrazino-pirimidinek és aromás aldehidek acilezési reakcióban nukleozid-analóg [1,2,4]triazolo[4,5-a]pirimidin-4-on származékokat eredményeznek. Javaslatot tettünk ezen új gyűrűzárási reakció mechanizmusára. Javasoltuk a Lipari-Szabó NMR relaxációs módszer kiterjesztését. Módszerünkkel fehérjékben meghatározható a kémiai eltolódások anizotrópiája (CSA) és az ún. geometriai faktor is. Új TROSY módszert javasoltunk az NH-H? csatolási állandók mérésére fehérjékben. Érzékeny, és pontos NMR módszereket fejlesztettünk ki gyengén orientált közegben maradék dipoláris csatolások, és diasztereotóp metilén-proton csatolások dipoláris járulékainak mérésével az új glikomimetikumok térszerkezetének jellemzésére. | 2D NMR and molecular modelling studies of lipophilic derivatives of peptidoglycan monomer (PGM) indicate that conformational changes induced by the substituents do not affect the biological activities of these compounds. Using similar approaches it was shown that binding of the LALF-14 inhibitor peptide to bacterial endotoxins (LPS) does not require the -sheet structure in the lipid-A binding region of full-size LALF protein as a prerequisite. Interactions between amide protons and side chain aromatic rings in helical dodecapeptides were identified by NOE-restrained molecular modelling. Diglycosyl disulfides and glycosyl sulfenamides were synthesized as the first representatives of novel glycomimetics with three-bond glycosidic linkages. Hydrazino-pyrimidines react with aromatic aldehydes under acylating conditions to furnish nucleoside analog [1,2,4]triazolo[4,5-a]pyrimidin-4-ones. A mechanism was proposed for these novel ring closing reactions. The Lipari-Szabó formalism for NMR relaxation data was extended for the determination of individual chemical shift anisotropies (CSA) and the geometry factors in proteins. A new TROSY sequence was developed to measure NH-H? couplings in proteins. Novel NMR methods were proposed to measure residual dipolar couplings and the dipolar contribution to the scalar coupling between diastereotopic protons in weakly aligned media. These NMR methods are of importance in the structural studies of the novel glycomimetics

MEDICAL IMAGE PROCESSING METHODS FOR THE DEVELOPMENT OF A VIRTUAL ENDOSCOPE

Virtual endoscopes give internal views of the human body without penetrating it, based on a set of parallel cross-sections produced with any computed tomography method. This paper presents some ideas concerning the design and implementation of a software system, which acts like a virtual endoscope. It takes into account the general requirements of the system, gives a solution that uses a multi-step algorithm, and finally shows the resulting 3-D images. Most of the algorithmic steps have several possible solutions. Some comparisons are made among them where appropriate. The quality of service provided by the chosen method mainly depends on the resolution of the input images

Non-normal affine monoids, modules and Poincaré series of plumbed 3-manifolds

We construct a non-normal affine monoid together with its modules associated with a negative definite plumbed 3-manifold M. In terms of their structure, we describe the H1(M, Z) -equivariant parts of the topological Poincaré series. In particular, we give combinatorial formulas for the Seiberg–Witten invariants of M and for polynomial generalizations defined in [17]. © 2017, Akadémiai Kiadó, Budapest, Hungary

INVESTIGATION OF THE CHANGES OF THE MASS MOMENTS OF INERTIA DURING A DOUBLE STEP OF RUNNING

INTRODUCTION: A new method for the investigation of athletes' motion takes into consideration the changes of the principal moments of inertia and their directions during the interval of the motion, because these characterize both the changes and the loss of energy. This paper investigates the motion of a runner. The applied model is a refined Hanavan model [1], representing the human body with 16 simple geometric solids determined by the spatial co-ordinates of 20 key points. METHODS AND PROCEDURES: The records were made by The Biomechanics Department of the Hungarian University of Physical Education with several video cameras. For the digitalization of the frames the APAS (Ariel Performance Analysis System) was used. The data of the digitized key points were analyzed by the system (MAS = Motion Analyzing System), developed for PC at the Department of Applied Mechanics of the Technical University of Budapest. Fig. 1 shows 11 different phases of the motion in the same picture. The time interval between the first and last phase is 0.9 sec. During the analysis 46 frames were digitized with a time-interval of 0.02 sec. This paper investigates the changes of the eigensystem for the mass moments of inertia of the whole human body with respect to the center of mass during the interval of the motion

Atrial Remodeling in Atrial Fibrillation. Comorbidities and Markers of Disease Progression Predict Catheter Ablation Outcome

Atrial fibrillation is the most common supraventricular arrhythmia affecting an increasing proportion of the population in which mainstream therapy, i.e. catheter ablation, provides freedom from arrhythmia in only a limited number of patients. Understanding the mechanism is key in order to find more effective therapies and to improve patient selection. In this review, the structural and electrophysiological changes of the atrial musculature that constitute atrial remodeling in atrial fibrillaton and how risk factors and markers of disease progression can predict catheter ablation outcome will be discussed in detail

Non-normal affine monoids, modules and Poincaré series of plumbed 3-manifolds

We construct a non-normal affine monoid together with its modules associated with a negative definite plumbed 3-manifold M. In terms of their structure, we describe the $H_1(M,\mathbb{Z})$-equivariant parts of the topological Poincaré series. In particular, we give combinatorial formulas for the Seiberg–Witten invariants of M and for polynomial generalizations defined in [17]

Widening Gap of Land Evaporation to Reference Evapotranspiration Implies Increasing Vulnerability to Droughts in Hungary

Severe droughts of 2022 in Europe raise the question if one has sufficient knowledge and tools to predict and prevent such events. Analysis of 40 years of meteorological data for Hungary between 1981 and 2020 confirms significant upward trends with p = 0.05 in temperature, relative humidity, and net radiation. Shortwave net radiation has increased by 89.6 mm in water equivalent. Estimates of land evaporation and reference evapotranspiration also show a significantly increasing trend. The gap between them is widening with a significant trend in northeast Hungary. The demand (reference evapotranspiration) is increasing by 2.23 ± 0.3 mm yr–1, while supply (land evaporation) by 1.64 ± 0.2 mm yr–1. The opening gap can be interpreted as a decreasing stability of the energy distribution system, where water is the dominant energy transfer medium for climatic energy. This change could lead to an increased risk of droughts, a symptom of system underperformance. The climatic energy distribution process – a key environmental service - is shifting to a new operating point where more water would be needed to transport energy. These trends call for a process capability approach. Desertification cannot be stopped by chasing water use efficiency and using less water, but vice versa: water scarcity can only be eliminated by ensuring that there is sufficient water available for evapotranspiration. This will raise the priority for initiatives to design and implement a wide range of preventing actions, such as nature-based solutions and water retention measures