Caffeine content of conventional and non conventional foods on the Hungarian market

Caffeine content of 377 food samples obtained from the Hungarian market was measured by a validated HPLC technique. The highest caffeine levels were observed in different instant coffees (3954±2355 mg/100 g) and ground coffee beans (1634±389 mg/100 g). Significant amount of caffeine could be detected in energy drinks (119 mg in 100 ml at the highest end). The caffeine content of different coffee drinks varied between 40 and 203 mg/100 ml. Significant amount of caffeine could be measured in special instant coffees called 2in1 and 3in1 (120 mg per serving at the highest end), cacao powders (125 mg in 100 g), in chocolates (on average, 16.1 mg and 52.5 mg in 100 g milk and dark chocolate, respectively), breakfast cereals (between 5.7 and 15.8 mg per 100 g), and ice creams (1.7–24.8 mg in 100 g)

Role of molecular architecture and temperature on extrusion melt flow instabilities of two industrial LLDPE and LDPE polyethylenes investigated by capillary rheology, high‐pressure sensitivity slit die and optical analysis

The characteristic time periodicity $\tau^{*}$ and the spatial characteristic wavelength ${\lambda}$ of extrusion flow instabilities of a linear and a branched commercial polyethylene (PE) are characterized via capillary rheology, optical analysis and modeled. The two investigated polyethylenes have the similar weight average molecular weight (Mw). The characteristic time periodicity $\tau^{*}$ is obtained and compared using three methods: (i) a highly sensitive pressure slit die, (ii) a new online optical analysis method based on the construction of a space–time diagrams, and (iii) an offline transmission polarization microscopy. In addition, the spatial characteristic wavelength ${\lambda}$ is quantified by offline transmission polarization microscopy. The characteristic time periodicity $\tau^{*}$ of the extrusion flow instabilities follows a power law behavior as a function of apparent shear rate to a power of −0.7 for both materials, $\tau$$^{*}{\propto^.\gamma}^{-0.7}_{app.}$. A qualitative model is used to predict the spatial characteristic wavelength of extrusion flow instabilities as well. It is found that the characteristic spatial wavelength ${\lambda}$ and the characteristic time periodicity $\tau^{*}$ have an Arrhenius temperature-dependent behavior

dUTPase based switch controls transfer of virulence genes in order to preserve integrity of the transferred mobile genetic elements

dUTPases ubiquitously regulate cellular dUTP levels to preserve genome integrity. Recently, several other cellular processes were reported to be controlled by dUTPases including the horizontal transfer of Staphylococcus aureus pathogenicity islands (SaPI). SaPIs are mobil genetic elements that encode virulence enhancing factors e.g. toxins. Here, phage dUTPases were proposed to counteract the repressor protein (Stl) and promote SaPI excision and transfer. A G protein-like mechanism was proposed which is unexpected in light of the kinetic mechanism of dUTPase. Here we investigate the molecular mechanism of SaPI transfer regulation, using numerous dUTPase variants and a wide range of in vitro methods (steady-state and transient kinetics, VIS and fluorescence spectroscopy, EMSA, quartz crystal microbalance, X-ray crystallography). Our results unambiguously show that Stl inhibits the enzymatic activity of dUTPase in the nM concentration range and dUTP strongly inhibits the dUTPase: Stl complexation. These results identify Stl as a highly potent dUTPase inhibitor protein and disprove the G protein-like mechanism. Importantly, our results clearly show that the dUTPase:dUTP complex is inaccessible to the Stl repressor. Unlike in small GTPases, hydrolysis of the substrate nucleoside triphosphate (dUTP in this case) is required prior to the interaction with the partner (Stl repressor in this case). We propose that dUTPase can efficiently interact with Stl and induce SaPI excision only if the cellular dUTP level is low (i.e. when dUTPase resides mainly in the apo enzyme form) while high dUTP levels would inhibit SaPI transfer. This mechanism may serve the preservation of the integrity of the transferred SaPI genes and links the well-known metabolic role of dUTPases to their newly revealed regulatory function in spread of virulence factors

Derivation of a Qualitative Model for the Spatial Characteristic Wavelength of Extrusion Flow Instabilities: Investigation of a Polybutadiene Rubber through Capillary, Slit and Complex Geometry Extrusion Dies

The extrusion flow instabilities of commercial polybutadiene (PBD) are investigated as a function of the different extrusion die geometries, such as round capillary, slit, and complex cross-section profile slit dies via capillary rheology. Qualitative models are used to fit the experimental data for the spatial characteristic wavelength (λ) of the appearing extrusion flow instabilities. A new qualitative model for the slit die geometry, rectangular cross-section, is derived based on the theoretical concept of the “two layers” extrudate and the force balance at the die exit region. The proposed qualitative model for the slit die geometry is used to predict the spatial characteristic wavelength (λ) for extrudates obtained by complex cross-section profile slit die geometries similar to industrial manufacturing. Correlation between the ratio of the extensional (Y$_s$) and shear (σ$_x$) stress at the die exit area and the characteristic dimension, height H for slit dies and diameter D for round capillary dies, is presented. Moreover, a geometry-dependent model is used to predict the spatial characteristic wavelength (λ) of the extrusion flow instabilities from a round capillary die to a slit die and vice versa

Magnetic hysteresis in Ising-like dipole-dipole model

Using zero temperature Monte Carlo simulations we have studied the magnetic hysteresis in a three-dimensional Ising model with nearest neighbor exchange and dipolar interaction. The average magnetization of spins located inside a sphere on a cubic lattice is determined as a function of magnetic field varied periodically. The simulations have justified the appearance of hysteresis and allowed us to have a deeper insight into the series of metastable states developed during this process.Comment: REVTEX, 10 pages including 4 figure

Mechano-Optical Characterization of Extrusion Flow Instabilities in Styrene-Butadiene Rubbers: Investigating the Influence of Molecular Properties and Die Geometry

The extrusion flow instabilities of two commercial styrene‐butadiene rubbers are investigated as they vary in isomer content (1,4‐cis, 1,4‐trans, and 1,2 conformation) of the butadiene monomer and the molecular architecture (linear, branched). The investigated samples have similar multimodal molecular weight distribution. Two geometries of extrusion dies, slit and round capillary, are compared in terms of the type and the spatial characteristics of the flow instabilities. The latter are quantified using three methods: a highly pressure sensitive slit die, online and offline optical analysis. The highly pressure‐sensitive slit die has three piezoelectric pressure transducers (Δt ≈ 10$^{-3}$ s and Δp ≈ 10$^{-5}$ bar) placed along the die length. The characteristic frequency (f$_{Char.}$) of the flow instabilities follows a power law behavior as a function of shear rate to a 0.5 power for both materials,  $_{ℎ.}$∝$^{˙0.5}$$_{app.}$. A qualitative model is used to predict the spatial characteristic wavelength (λ) of the flow instabilities from round capillary to slit dies and vice versa. Slip velocities (V$_{s}$) are used to quantify the slippage at slit and round capillary dies as well

An Intriguing Array of Extrudate Patterns in Long‐Chain Branched Polymers During Extrusion

The present study highlights a range of surface and volume extrudate patterns that can be detected during the extrusion flow of long-chain branched polymers. Thus, four linear low-density polyethylenes (LDPEs) have been extruded using a single-screw extruder coupled to an inline optical imaging system. The selected LDPEs are selected to outline the influence of molecular weight and long-chain branching on the types of melt flow extrusion instabilities (MFEI). Through the inline imaging system, space–time diagrams are constructed and analyzed via Fourier-transformation using a custom moving window procedure. Based on the number of characteristic frequencies, peak broadness, and whether they are surface or volume distortions, three main MFEI types, distinct from those typically observed in linear and short-chain branched polymers, are identified. The higher molecular weight, low long-chain branching LDPEs exhibited all three instability types, including a special type volume instability. Independently of the molecular weight, higher long-chain branching appeared to have a stabilizing effect on the transition sequences by suppressing volume extrudate distortions or limiting surface patters to a form of weak intensity type

The Effect of Surfactants and pH Modifying Agents on the Dissolution and Permeation of Pimobendan

Solubility and permeability are key parameters for establishing in vitro-in vivo correlation for poorly water-soluble active pharmaceutical ingredients (APIs). Recent studies demonstrate that not only solubility, but also effective permeability of the API may change due to the addition of solubilizing agents, and there is a certain mathematical relation between these physicochemical parameters. The aim of this study was to show the importance of early screening of solubility and permeability in presence of additives in order to achieve the expected bioavailability of the API. In this work, the effect of surfactants and microenvironmental pH modifiers were in focus, and pimobendan was chosen as model drug.In the case of pH modifiers, the equilibrium solubility of the API increased, while the permeability decreased significantly. No negative effect was observed for two surfactants at low additive levels, but these two additives also exhibited a slightly negative effect on permeability when used at higher concentrations. In the simultaneous dissolution-permeation studies the surfactants-containing formulation was found to have slightly higher flux than the pH-modifier-containing one. It can be due to the phenomenon that the dissolution of the active substance can be enhanced by these surfactants without any significant permeability reducing effect.The results obtained from the present study clearly demonstrate the importance of studying drug-additive interactions in every step of formulation development and based on these, the selection of the appropriate quality and quantity of additives. In addition, the results also underline the significance of performing simultaneous dissolution-permeation studies to predict bioavailability

Több-billentyűs redoműtét felnőtt betegen komplex pulmonalis atresiában

Absztrakt: A 30 éves, komplex pulmonalis atresiás betegnél csecsemőkorban az unifokalizálás eldönthetősége miatt exploratio, 10 éves korban rekonstrukciós műtét (kamrai sövényhiány zárása, unifokalizáció, jobb kamra–arteria pulmonalis folytonosságának kialakítása homografttal) történt. A mindkét kamra csökkent működését okozó aortabillentyű-elégtelenség és ascendenstágulat, illetve homograftelégtelenség miatt az aortabillentyű plasztikája, a pulmonalis billentyű, illetve az aorta ascendens és arteria pulmonalis törzs cseréje vált szükségessé. Magyarországon betegünk az első, akinél ilyen redoműtét történt. A műtét sikere igazolja, hogy megfelelő gondozás, diagnosztika (echokardiográfia, MR, CT) mellett az időben történt műtét jó korai és késői eredményt biztosíthat a komplex szívhibás, felnőttkorú betegek számára. Orv. Hetil., 2017, 158(14), 546–549. | Abstract: 30-year-old adult with complex pulmonary atresia (previous surgical procedures: in infancy: exploration, at age of 10: ventricular septal defect closing, unifocalization, homograft implantation between right ventricular outflow tract and pulmonary artery) has biventricular dysfunction because of aortic valve regurgitation, ascending aortic aneurysm, and homograft insufficienty. Multivalve surgery: aortic valve plasty, pulmonary homograft changes for homograft and ascending aortic reconstruction by graft were carried out successfully. In Hungary this was the first case of this type of surgery. Management of special problems (follow-up, correct diagnostics (echocardiography, MR, CT), indication and necessity of reoperation, optimal age) in adult patients with complex congenital heart defects produces excellent early and late surgical results. Orv. Hetil., 2017, 158(14), 546–549

Polygon model from first order gravity

The gauge fixed polygon model of 2+1 gravity with zero cosmological constant and arbitrary number of spinless point particles is reconstructed from the first order formalism of the theory in terms of the triad and the spin connection. The induced symplectic structure is calculated and shown to agree with the canonical one in terms of the variables.Comment: 20 pages, presentation improved, typos correcte