Properties of minimally tt-tough graphs

A graph $G$ is minimally $t$-tough if the toughness of $G$ is $t$ and the deletion of any edge from $G$ decreases the toughness. Kriesell conjectured that for every minimally $1$-tough graph the minimum degree $\delta(G)=2$. We show that in every minimally $1$-tough graph $\delta(G)\le\frac{n+2}{3}$. We also prove that every minimally $1$-tough claw-free graph is a cycle. On the other hand, we show that for every $t \in \mathbb{Q}$ any graph can be embedded as an induced subgraph into a minimally $t$-tough graph

A Network Theory Approach to the Sharing Economy

With the rapid growth of businesses in the sharing economy, evidence is accumulating regarding their underlying business models, growth patterns and other characteristics.This article demonstrates that a network theory approach can be useful for analysing the internal structure and other features of sharing economy platforms and the networks created by them. After introducing the most important concepts and theoretical considerations relating to the sharing economy, we analyse the data of a regional ride share company based in Hungary. Our analysis reveals an increasingly popular service, which is in a phase of rapid growth in terms of both the number of origin/destination settlements and the number of trips/passengers. Taking settlements as nodes and trips between them as edges we demonstrate that the network formed by them shows the characteristics of scale-free networks.Our findings may help company managers and policy makers to fine tune their decisions and indicate potential areas for further research directions to better understand the societal effects of the sharing economy

A gyermekkori 1-es típusú diabétesz genetikai és humorális immunológiai hátterének vizsgálata = Genetic and humoral immunologic determinants of childhood-onset type 1 diabetes

Az OTKA pályázat munkatervében kitűzött célok megvalósultak. A program az elmúlt három év alatt országos diabetes genetikai projektté nőtte ki magát (HUN-T1D-GENES program; www.diabet.hu/ diabetesgenetics). Az elért kutatási és a gyakorlatban hasznosítható eredmények felsorolása: 1. Kiterjedt genetikai vizsgálatokat végeztünk több mint 1400 1-es típusú diabeteses gyermekben és családtagjaikban. A HLA vizsgálatok során több mint 340 magas rizikójú, még nem diabeteses gyermeket azonosítottunk. 2. Karakterizáltuk az 1-es típusú diabetes HLA Class II, valamint 2 új non-Class II fogékonysági genetikai faktorát (HLA B39, C4B) a magyar populációban. 3. Meghatároztuk három fontos non-HLA gén (INS, CTLA4, PTPN22) által kódolt T1D genetikai rizikó mértékét, és azok részvételét az autoimmune folyamat kontrolljában. 4. Kidolgoztunk egy a magyar népességre alkalmazható komprehenzív populációgenetikai szűrési modellt mellyel azonosíthatók az 1-es típusú diabetesre magas rizikójú egyének. 5. Kidolgoztunk egy a klinikai gyakorlatban használható protokollt, mely segítséget nyújt a klinikusoknak a diabetesre magas rizikójú gyermekek klinikai követésére. Ez a protokoll elősegíti azt hogy az 1-es típusú diabetes korábban kerüljön felismerésre ezekben a gyermekekben. Ezáltal csökkenthető a korai mortalitás és morbiditás ebben a csoportban. 6. A KCNJ11 gén esetében egy új génvariánst azonosítottunk egy neonatalis diabetes-es páciensben. | The project goals have been sucessfully achieved. During the last 3 years the project has grown to a national type 1 diabetes genetics program (HUN-T1D-GENES; www.diabet.hu/ diabetesgenetics). The following milestones have been achieved: 1. An extensive genetic analysis have been carried out in more than 1400 Hungarian type 1 diabetes nuclear families. We identified approximately 340 siblings at high genetic risk for the disease. 2. We characterised in details the contribution of the HLA Class II genes to disease risk and identified 2 novel non-Class II disease genetic determinants (HLA B39 and C4B). 3. The association of three non-HLA genes with T1D was characterized, and their role in the control of autoimmunity was described as well. 4. A step-wise genetic screening model was developed for the Hungarian population which enables identification of high risk subjects in the general population and also among first degree relatives of patients. 5. A consensus protocol has been developed for the clinical follow-up of children at high genetic risk for type 1 diabetes. This enables early diagnosis and helps to reduce early mortality and morbidity. 6. A new variant of the KCNJ11 gene was identified in a case with neonatal diabetes

Always up or peaks and highlands? Incidence of childhood type 1 diabetes in Hungary 1989-2009

Aim of this study was to examine secular trends in the incidence of type 1 diabetes in children aged 0–14 years in Hungary over the period 1989–2009. Methods: Newly diagnosed children with type 1 diabetes aged 0–14 years in Hungary were prospectively registered from 1989 to 2009. Standardized incidence rates were calculated and secular trends were estimated using Poisson regression analysis. Results: Between 1989 and 2009 a total number of 3432 children were identified, giving a standardized incidence rate of 12.5 (95%CI 12.1–12.9) per 100 000 person/year. The overall incidence rate has doubled from 7.7 (95%CI 6.4–9.15) per 100 000 per year in 1989 to 18.2 (95%CI 15.7–20.9) per 100 000 per year in 2009. A significant linear trend in incidence (p&lt;0.001) has been observed over time, with a mean annual increase of 4.4%. The increase in incidence was present in both genders and in all age groups, with the largest relative increase in the youngest age group (6.2%; p&lt;0.001). Conclusion: The incidence of type 1 diabetes in Hungarian children continues to increase, with the highest rate in the very young. Orv. Hetil., 2011, 152, 1692–1697.</jats:p

Immuno-inflammatorikus mechanizmusok antifoszfolipid szindróma atherothromboticus folyamataiban = Immunopathological mechanism in atherothrombotic processes af antipospholipid syndrome

A fő célkitűzés az atherothrombosis és a gyulladás kapcsolatának vizsgálata volt. Az antifoszfolipid szindróma mellett az oxidált-LDL ellenes antitestek szerepét is tanulmányoztuk. A T-helper1/T-helper2 ballance adatokat adott a B-sejt aktivációs cytokinek szerepére akut és stabil coronaria betegségben. Az immun-medált paramétereket összevetettük az endothel dependens vasodilatáció, az artéria carotis intima-média falvastagság illetve az artériás stiffness angiológiai paraméterekkel. Elsőként mutattuk ki, antifoszfolipid szindrómában, hogy az endothel funkció károsodik, a carotis intima- média falvastagság növekszik (Lupus). Metodikai aspektussal vizsgálva összefüggést találtunk az artéria brachiális flow-mediált vasodilatáció és az augmentációs index pozitív korrelációs kapcsolatára. Intracytoplazmatikus cytokinek meghatározásával adatokat szolgáltattunk a B-sejt aktivációs mechanizmusokra plakk immuno-inflammatórkius folyamataiban (Scand J. Immunol). Elsőként határoztuk meg a magyarországi perifériás érbetegek reprezentatív mintájában az antifoszfolipid antitestek előfordulását (Érbetegségek). Az immunmediált folyamatok angiológiai hatásának vizsgálatát kiterjesztettük Rheumatoid Arthritisben és Sclerodermában szenvedő betegekre is (Rheumatology). Az oxidált-LDL ellenes antitesteket vizsgálva meghatároztuk prediktív értékét a stabil coronaria betegek betegségének instabillá válásában. (Thromb and Haem.) | The primary aim was to study the association between atherothrombosis and inflammation. The prototype of the study was the antiphospholipide syndrome. Besides antiphospholipid antibodies, we also analyzed the possible role of oxidized LDL antibodies in atherothrombotic processes. By specifying the Th1/Th2 ballance, we tried to find evidence to the role of B cell activating cytokines in acute and stable CAD. We searched correlations between immunoinflammatic, and such angiologic parameters like endothel dependent vasodilatation, carotid intima media thickness and arterial stiffness parameters. We were the first to demonstrate in antiphospholipid syndrome the dysfunction of the endothel, the increase of carotid intima media thickness (Lupus). We found positive correlation between brachial artery flow mediated vasodilatation and augmentation index. We found a possible role of B cell activated mechanisms in immunoinflammatoric processes of atherosclerotic plaque in acute and stable coronary artery disease (Scand. J. Immunol), investigating them separately. We expanded the examination of angiological effects of immune mediated processes to patients suffering from rheumatoid arthritis and scleroderma (Rheumatology). We analysed the predictive role of antibodies to oxidized LDL in the outcome of acute coronary syndrome, and we detected its predictive value in turning a stable coronary artery disease into an unstable clinical state. (Thromb and Haem.

Alterations in the properties of the cell membrane due to glycosphingolipid accumulation in a model of Gaucher disease

K