Gy. Tóth

Differential scanning calorimetric examination of the human intervertebral disc: a preliminary study

Abstract Intervertebral disc degeneration is a common orthopaedic disorder with significant social and economic impact. The major pathological changes occur in the structure of anulus fibrosus and nucleus pulposus. Differential scanning calorimetry (DSC) is a well-established method for the demonstration of thermal consequences of local and global conformational changes in biological systems. It has never been applied for the investigation of intervertebral disc. According to the present study, the thermograms may prove and follow the changes in the structure of degenerated intervertebral discs. Differences were clearly demonstrated between the two major parts of the intervertebral discs as well as healthy and degenerated samples with the changes in total enthalpy and heat capacity.

Vagal nerve and the gastric mucosal defense

An essential role for an intact vagal nerve has been proven in the development of gastric mucosal cyto- and general protection. On the other hand, chemically-induced (ethanol, HCl, indomethacin) gastric mucosal damage is enhanced after acute surgical vagotomy. The aims of this paper were to study the possible mechanisms of the vagal nerve in the development of gastric mucosal defense. The following questions were addressed: 1) effect of surgical vagotomy on the development of ethanol- (ETOH), HCl-, and indomethacin (IND)-induced gastric mucosal damage: 2) changes in the gastric mucosal defense by scavengers, prostacyclin and other compounds (small doses of atropine and cimetidine; 3) changes in the gastric mucosal vascular permeability due to chemicals; 4) effect of indomethacin in the ETOH and HCl models with and without surgical vagotomy; 5) changes in the gastric mucosal content of prostacyclin and PGE2 in the ETOH and HCl models after surgical vagotomy; and 6) changes in the role of SH-groups in gastric mucosal defense after surgical vagotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the Vagal Nerve in the Development of Gastric Mucosal Injury and its Prevention by Atropine, Cimetidine, β-Carotene and Prostacyclin in Rats

Peptic ulceration including acute erosions is a multifactorial disease involving well-known factors such as trauma, stress, sepsis, hemorrhagic shock, burns, pulmonary and liver diseases1–9 and drugs such as reserpine10, epinephrine11–13, nonsteroidal antiinflammatory drugs7, steroids and other chemicals14.

Interplay of diffraction and nonlinear effects in the propagation of ultrashort pulses

We investigate the interplay of diffraction and nonlinear effects during the propagation of very short light pulses. Adapting the factorization approach to the problem at hand by keeping the transverse-derivative terms apart from the residual nonlinear contributions we derive an unidirectional propagation equation which is valid for weak dispersion and reduces to the slowly-evolving-wave-approximation in the case of paraxial rays. A comparison of the numerical simulation results for the two equations shows pronounced differences when self-focusing plays an important role. We devote special attention to modelling the propagation of ultrashort terahertz pulses taking into account diffraction as well as Kerr-type and second-order nonlinearities. Comparing the measured and simulated wave forms we deduce the value of the nonlinear refractive index of lithium niobate in the terahertz region to be three orders of magnitude larger than in the visible part of the spectrum.

Proposal for sub-femtosecond pulse generation with controlled carrier-envelope phase

A robust method for producing few-cycle pulses with controlled waveform in the EUV-VUV spectral range by coherent undulator radiation of relativistic ultrathin electron layers produced by inverse free-electron laser (IFEL) action is proposed. The realization of such exceptional pulses will enable time- and CEP-resolved measurements with less than 100 as resolution.

Evanescent-wave proton post-accelerator driven by intense THz pulses

Here, a compact solution is proposed for post-acceleration and monochromatization of particles leaving the laser-driven accelerator. The proposed method relies on the evanescent field of intense THz pulses undergoing total internal reflection at symmetrically arranged dielectric-vacuum interfaces. THz pulses in the 0.1-1 THz frequency range are promising for this application, due to their advantageous wavelength, and to the fact that they can be generated with extremely high electric field strength (>1 MV/cm), and pulse energy (125 μJ) in LiNbO3 (LN) by tilted-pulse-front excitation. Choosing LN as the dielectric material of the evanescent accelerator has the important advantage that it can function also as THz source leading to a very compact setup.

Serum Carotenoids and Malignant Gastrointestinal Diseases in Patients

The serum levels of carotenoids (vitamin A, lutein, zeaxanthin, α- and β-cryptoxanthin, α- and β- carotene) were measured in healthy people and in patients with different malignant gastrointestinal diseases (21 colon, 13 stomach, 8 pancreas adenocarcinoma, 10 hepatocellular carcinoma). The serum levels of carotenoids were measured with high pressure liquid chromatography (HPLC). The sera of the patients were taken at the time of the diagnosis.