Az erős kölcsönhatás vizsgálata a XXI. század gyorsítóira jellemző energiákon = Study of strong interaction dynamics at energies of colliders in the XXI. century

Az erős kölcsönhatásnak az LHC gyorsítón történő vizsgálata céljából továbbfejlesztettük a kísérletek megtervezéséhez és az adatok kiértékeléséhez szükséges elméleti eszköztárat. Olyan általános módszert fejlesztettünk ki dzset hatáskeresztmetszetek első sugárzási korrekcióinak (NLO pontosság) kiszámítására, amelyben a parton tömegek tetszőlegesen választhatók feltéve, ha a kiszámítandó fizikai mennyiség értelmes a nulla-tömegű határesetben is. Teljesen numerikus eljárást javasoltunk NLO korrekciók számítására, valamint új partonzápor algoritmust dolgoztunk ki, amelynek az erős csatolás szerinti sorfejtése visszaadja az NLO pontosságú számolás eredményét. Felderítettük a faszintű QCD mátrixelemek szingularitásszerkezetét azokban az átfedő tartományokban, amelyekben egy vagy két parton válik feloldhatatlanná. Elsőként véghezvittünk néhány áttörő jellegű sugárzási-korrekció számítást: 1) a foton-foton szórás teljes hatáskeresztmetszetéhez a teljes NLO és az NNLO korrekciók egy mértékinvariáns részét, 2) a mélyen rugalmatlan elektronszórásban való három-dzset keletkezés, valamint 3) a hadronütközésekben való három-dzset keletkezés NLO pontosságú hatáskeresztmetszetét. A LEP OPAL detektorával gyűjtött adatok kiértékelésével megmértük a foton-foton szórás teljes hatáskeresztmetszetét, valamint részt vettünk 16 OPAL cikk közlésre való előkészítésében. | In order to prepare for the investigation of the strong interaction dynamics at the LHC, we have developed theoretical tools needed for devising the experiments and analyzing data. We have developed a general method for computing jet cross sections at the next-to-leading order (NLO) accuracy such that the parton masses can be chosen arbitrarily provided the zero-mass limit of the observable to be computed is well defined. We have suggested a completely numerical method for computing NLO corrections in QCD and a new parton shower algorithm that reproduces the exact fixed-order (LO and NLO) predictions when expanded in the strong coupling. We have disentangled completely the various singularities of the tree-level squared matrix elements of QCD when one or two partons become unresolved. We have also made several breakthrough computations for predicting cross sections of elementary particle interactions: 1) the NLO and a gauge invariant part of the NNLO corrections to the total cross section of virtual photon-photon scattering, 2) the NLO corrections to three-jet production in deeply inelastic scattering and 3) the NLO corrections to three-jet production in hadron-hadron scattering. All these predictions had been unprecedented in the literature. We have also measured the total cross section of virtual photon-photon scattering using the data collected with the OPAL detector at LEP. In addition, we have participated in the preparation of 16 OPAL research papers for publication

A Standard Modell ellenőrzése elektron-pozitron és proton-proton ütközésekben = Test of the Standard Model in electron-positron and proton-proton collisions

A pályázat támogatásával csoportunk befejezte a CERN LEP gyorsítójának OPAL kísérletében korábban megkezdett munkáját, majd csatlakozott a rövidesen induló LHC CMS kísérletéhez. Az OPAL adatait analizálva egyebek között a töltött Higgs bozonokra adtunk alsó tömeghatárt, illetve a foton-foton ütközésekben történő hadronképződést vizsgáltuk. A CMS kísérletben a szuperszimmetrikus részecskéket kereső munkacsoport tevékenységébe kapcsolódtunk be, továbbá a kísérlet elosztott számítógépes hátterének (LHC Grid) magyarországi részét telepítettük és teszteltük. Jelenleg a CMS ún. T2 szintű számítási és adattárolási kapacitásának kb. 2%-át biztosítjuk, és az együttműködés többi résztvevőjével közösen folytatjuk a felkészülést az LHC indulásakor érkező adatok feldolgozására. | With this grant our group concluded its ongoing work in the OPAL experiment at CERN's LEP accelarator, and joined the CMS experiment of the starting LHC. Analysing OPAL data we gave, among others, a lower mass limit for charged Higgs bosons, and investigated hadron production in photon-photon collisions. In the CMS experiment we joined the group searching for supersymmetric particles, and we installed and tested the Hungarian part of the experiment's distributed computing infrastructure (LHC Grid). At the moment we cover about 2% of the T2 level CMS computing and storage capacity, and along with other participants of the collaboration we are continuing the preparations for handling the data that will arrive after the LHC startup

Biomassza hasznosítás kémiai alapfolyamatainak tanulmányozása = Study of fundamental chemical processes of biomass utilization

(1) Biomassza anyagok széles skáláját vizsgáltuk termikus módszerekkel. A hőbomlásról, az égési folyamatokról, és az elgázosításról nyertünk ismereteket, valamint hozzájárultunk egyes biomassza-hasznosítási eljárások során lejátszódó folyamatok mélyebb megértéséhez. Olyan reakciókinetikai modelleket alkalmaztunk, ill. dolgoztunk ki, melyek nagyobb mérési sorozatokon, a kísérleti körülmények széles tartományában írják le a vizsgált termikus reakciókat, és tükrözték a vizsgált minták szerkezetének és felépítésének komplikált voltát. (2) Bioetanol gyártás tématerületen öt szubsztráton (gőzrobbantással előkezelt cukorcirok bagasz, kender, kender pozdorja és kontrollként két modell szubsztrát) vizsgáltuk a Tween 80 és a PEG 4000 adalékanyagok hatását különböző hőmérsékleteken. Kísérleteinkben kimutattuk, hogy ezen adalékanyagok hozzáadásával növelhető a szubsztrátok enzimes lebontásának hatékonysága. Cukorcirok alapú technológiák anyag- és energiamérlegének modellezésével igazoltuk, hogy a teljes termelési időszak alatt biztosítani lehet az üzem hőigényét a melléktermékek felhasználásával. (3) Bioszorbenseket állítottunk elő lignocellulóz típusú agro-hulladékokból (kipréselt repce pellet, keményítőmentes búzamag) kémiai módosításokkal, amelyek így alkalmasak voltak szervetlen illetve szerves anyagok (szennyezők) megkötésére. | (1) A wide range of biomass materials have been studied by thermal analysis and related methods. New knowledge was obtained on the thermal decomposition, combustion processes and gasification by CO2. The work contributed to a deeper understanding of the reactions taking place during various biomass utilization methods. Such reaction kinetic models were employed and developed that reflected the complexity of the studied materials and described larger series of experiments at various experimental conditions. (2) In the field of bioethanol production the effect of Tween 80 and PEG 4000 additives on five substrates (steam pretreated sweet sorghum bagasse, hemp, hemp hurds and two model substrates) was investigated at various temperatures. It was proven that these additives could increase the efficiency of enzymatic digestibility of these substrates. By modeling the mass and energy balances of sweet sorghum based technologies it was verified that the heat demand of the process can be covered during the whole production period by utilizing the by-products. (3) Biosorbents were prepared from lignocellulosic agricultural wastes (pressed rape seed pellet, starch free wheat seed) by chemical modifications. The products were suitable to bond organic and inorganic pollutants

Hypermuscular mice with mutation in the myostatin gene display altered calcium signalling

Myostatin, a member of the transforming growth factor β family, is a potent negative regulator of skeletal muscle growth, as myostatin-deficient mice show a great increase in muscle mass. Yet the physical performance of these animals is reduced. As an explanation for this, alterations in the steps in excitation–contraction coupling were hypothesized and tested for in mice with the 12 bp deletion in the propeptide region of themyostatin precursor (MstnCmpt-dl1Abc or Cmpt). In voluntary wheel running, control C57BL/6 mice performed better than the mutant animals in both maximal speed and total distance covered. Despite the previously described lower specific force of Cmpt animals, the pCa–force relationship, determined on chemically permeabilized fibre segments, did not show any significant difference between the two mouse strains.While resting intracellular Ca2+ concentration ([Ca2+]i)measured on single intact flexor digitorum brevis (FDB) muscle fibres using Fura-2 AM was similar to control (72.0 ± 1.7 vs. 78.1 ± 2.9 nM, n = 38 and 45), the amplitude of KCl-evoked calcium transients was smaller (360 ± 49 vs. 222 ± 45 nM, n = 22) in the mutant strain. Similar results were obtained using tetanic stimulation and Rhod-2 AM, which gave calcium transients that were smaller (2.42±0.11 vs. 2.06 ± 0.10 �F/F0, n = 14 and 13, respectively) on Cmpt mice. Sarcoplasmic reticulum (SR) calcium release flux calculated from these transients showed a reduced peak (23.7 ± 3.0 vs. 15.8 ± 2.1 mMs−1) and steady level (5.7 ± 0.7 vs. 3.7 ± 0.5 mM s−1) with no change in the peak-to-steady ratio. The amplitude and spatial spread of calcium release events detected on permeabilized FDB fibres were also significantly smaller in mutant mice. These results suggest that reduced SR calcium release underlies the reduced muscle force in Cmpt animal

The effect of tear supplementation with 0.15% preservative-free zinc-hyaluronate on ocular surface sensations in patients with dry eye

[Purpose]: To evaluate the effect of tear supplementation with preservative free 0.15% zinc-hyaluronate on ocular surface sensations and corneal sensitivity in dry eye patients.[Methods]: Ocular surface sensations were assessed using the ocular surface disease index (OSDI) questionnaire and by recording ocular sensations during forced blinking in parallel with noninvasive tear film breakup time measurement in 20 eyes of 20 dry eye patients. Corneal sensitivity thresholds to selective stimulation of corneal mechano-, thermal- and chemical receptors were measured using the Belmonte gas esthesiometer. All baseline measurements were repeated after 1 month of treatment with 0.15% zinc-hyaluronate.[Results]: After 1 month, a significant decrease in mean OSDI score (from 35.66 ± 12.36 to 15.03 ± 11.22; P 0.05).[Conclusion]: Prolonged use of 0.15% zinc-hyaluronate results in an improvement of tear film stability and a decrease of dry eye complaints. The decrease in corneal mechano-and polymodal receptor excitability suggests that zinc-hyaluronate helps to recover normal corneal sensitivity, and thus might have a beneficial additional effect on reducing ocular surface complaints in dry eye patients.Peer reviewe

Examination of the diaphragm in obstructive sleep apnoea, using ultrasound imaging

PURPOSE: The aim of this study was to analyze the effect of obstructive sleep apnea (OSA) on the ultrasound (US) features of the diaphragm and to determine if diaphragmatic US may be a useful screening tool for patients with possible OSA. METHODS: Patients complaining of snoring were prospectively enrolled for overnight polygraphy using the ApneaLink Air device. Thickness and motion of the diaphragm during tidal and deep inspiration were measured. Logistic regression was used to assess parameters of the diaphragm associated with OSA. RESULTS: Of 100 patients, 64 were defined as having OSA. Thicknesses of the left and right hemidiaphragms were significantly different between OSA and control groups. Using a combination of diaphragmatic dimensions, diaphragm dilation, age, sex, and BMI, we developed an algorithm that predicted the presence of OSA with 91% sensitivity and 81% specificity. CONCLUSION: A combination of anthropometric measurements, demographic factors, and US imaging may be useful for screening patients for possible OSA. These findings need to be confirmed in larger sample sizes in different clinical settings

Evaluation of Intereye Corneal Asymmetry in Patients with Keratoconus. A Scheimpflug Imaging Study

Purpose: To assess the correlation between keratoconus severity and intereye asymmetry of pachymetric data and posterior elevation values and to evaluate their combined accuracy in discriminating normal corneas from those with keratoconus. Methods: This study included 97 patients: 65 subjects with bilateral normal corneas (NC) and 32 with keratoconus (KC). Central corneal thickness (CCT), thinnest corneal thickness (ThCT) and posterior elevation (PE) at the thinnest point of the cornea were measured in both eyes using Scheimpflug imaging. Intereye asymmetry and its correlation with keratoconus severity were calculated for each variable. The area under the receiver operating characteristic curve (AUROC) was used to compare predictive accuracy of different variables for keratoconus. Results: In normal eyes, intereye differences were significantly lower compared with the keratoconus eyes (p<0.001, for CCT, ThCT and PE). There was a significant exponential correlation between disease severity and intereye asymmetry of steep keratometry (r(2) = 0.55, p<0.001), CCT (r(2) = 0.39, p<0.001), ThCT (r(2) = 0.48, p<0.001) and PE (r(2) = 0.64, p<0.001). After adjustment for keratoconus severity, asymmetry in thinnest pachymetry proved to be the best parameter to characterize intereye corneal asymmetry in keratoconus. This variable had high accuracy and significantly better discriminating ability (AUROC: 0.99) for KC than posterior elevation (AUROC: 0.96), ThCT (AUROC: 0.94) or CCT (AUROC: 0.92) alone. Conclusions: There is an increased intereye asymmetry in keratometry, pachymetry and posterior corneal elevation values in keratoconic patients compared to subjects with normal corneas. Keratoconus patients with more severe disease are also more asymmetric in their disease status which should be taken into account during clinical care