Search

Oxidative dehydrogenative coupling (ODC) is a useful tool for the formation of new C–C, C–O and NN bonds in an atom-economic and sustainable manner. Although this strategy is versatile, it is much less introduced to prepare N-heterocycles. Herein, we report the oxidative dehydrogenative coupling of anilines and 2-aminoanilies with vicinal diols to selectively produce azobenzenes (34–95% yield), quinolines (65–100% yield) and quinoxalines (78–100% yield) utilizing an environmentally friendly synthesis strategy. The reactions were catalysed by cooperative bifunctional catalysts based on transition metal oxides/Bi(iii) which allow solvent-, additive-, oxidant- and base-free cyclisations/couplings. In addition, the catalysts were proven to be highly robust and reusable.

Exploring the kinetics of metal–organic framework crystallization is crucial in order to design novel synthesis methods benefiting from far-from-equilibrium conditions, such as flow, microfluidic, or gel-phase reactors. Herein we focus on zeolitic imidazolate frameworks (ZIFs) obtained in the reaction of 2-methylimidazolate and zinc ions as a model system. The room-temperature synthesis carried out in pure water solvent without the addition of any alkaline chemical yields a highly crystalline product with good conversion within minutes. The short-term kinetic characteristics were determined by a high-speed camera, the result of which was complemented by a UV–vis photometer based long-term investigation. At low concentrations and moderate linker excess, which facilitate sluggish coordination and precipitation, a fast colloid formation is followed by a delayed and remarkable recrystallization, which leads to the formation of a dense dia(Zn) polymorph of ZIF. Although this is the thermodynamically favored route, it should be avoided due to the nonporous structure of the product. The same stoichiometric excess of the linker ions together with higher concentrations gives rise to the production of the thermodynamically less stable polymorph of ZIF: i.e., ZIF-8 with a sodalite-like structure is obtained via kinetic control. Similar conclusions are drawn in the case of cobalt(II)-containing imidazolate frameworks, which highlights that kinetic control based polymorph selection might be achieved for other MOFs as well. Our kinetic results were supported by scanning electron microscopy, powder X-ray diffraction, nitrogen gas adsorption, and Fourier-transformed infrared and Raman spectroscopy.

Although using supported noble-metal catalysts for CO2hydrogenation is an effective solution due to their excellent catalytic properties, metal oxide supports themselves can exhibit good activity being more economically feasible. This work focuses on investigating the complexity of the Co3O4system during the CO2methanation reaction, which is usually accompanied by the formation of unstable dispersions of cobalt oxide and metallic Co. Herein, we have tested different types of Co3O4: synthetically prepared mesoporous m-Co3O4(BET surface area, 95 m2/g) and commercial c-Co3O4(BET surface area, 15 m2/g; purchased from Merck) in the CO2methanation reaction under different reduction temperatures (273–673 K). The reduction temperature was adjusted to 573 K for both the catalysts to reach the optimal Co/cobalt oxide ratio and consequently the best catalytic performance. m-Co3O4is more active (CO2conversion 95%) and stable at higher temperatures compared to c-Co3O4(CO2conversion 63%) due to its morphology-induced ∼66 times higher surface basicity. DRIFTS results showed differences in the detected surface species: formate was observed on m-Co3O4and was proven to contribute to the total methane formation. It was revealed that in CO2methanation reaction, both bulk and surface properties such as morphology, cobalt oxidation states, acid–base properties, and presence of defect sites directly affect the catalytic performance and reaction mechanism. Furthermore, 1% 5 nm Pt nanoparticles were loaded onto the Co3O4s to check the competitiveness of the catalysts. This study evidences on a cheap noble-metal-free catalyst for CO2methanation consisting of m-Co3O4with competitive activity and ∼100% CH4selectivity.

Although gilt silver threads were widely used for decorating historical textiles, their manufacturing techniques have been elusive for centuries. Contemporary written sources give only limited, sometimes ambiguous information, and detailed cross-sectional study of the microscale soft noble metal objects has been hindered by sample preparation. In this work, to give a thorough characterization of historical gilt silver threads, nano- and microscale textural, chemical, and structural data on cross sections, prepared by focused ion beam milling, were collected, using various electron-optical methods (high-resolution scanning electron microscopy (SEM), wavelength-dispersive electron probe microanalysis (EPMA), electron backscattered diffraction (EBSD) combined with energy-dispersive electron probe microanalysis (EDX), transmission electron microscopy (TEM) combined with EDX, and micro-Raman spectroscopy. The thickness of the gold coating varied between 70–400 nm. Data reveal nano- and microscale metallurgy-related, gilding-related and corrosion-related inhomogeneities in the silver base. These inhomogeneities account for the limitations of surface analysis when tracking gilding methods of historical metal threads, and explain why chemical information has to be connected to 3D texture on submicrometre scale. The geometry and chemical composition (lack of mercury, copper) of the gold/silver interface prove that the ancient gilding technology was diffusion bonding. The observed differences in the copper content of the silver base of the different thread types suggest intentional technological choice. Among the examined textiles of different ages (13th–17th centuries) and provenances narrow technological variation has been found.

•Photo-acoustic stimulation is used to induce altered states of consciousness.•Photo-acoustic stimulation also leads to changes in the composition of saliva.•There are cumulative and pattern specific effects of photo-acoustic stimulation.•Values of cumulative or pattern specific effects are relatively small in this study.•The use of other stimulatory parameters may lead to more pronounced effects.

The development of highly active acid–base catalysts for transfer hydrogenations of biomass derived carbonyl compounds is a pressing challenge. Solid frustrated Lewis pairs (FLP) catalysis is possibly a solution, but the development of this concept is still at a very early stage. Herein, stable, phase-pure, crystalline hydrotalcite-like compounds were synthesized by incorporating cerium cations into layered double hydroxide (MgAlCe-LDH). Besides the insertion of well-isolated cerium centers surrounded by hydroxyl groups, the formation of hydroxyl vacancies near the aluminum centers, which were formed by the insertion of cerium centers into the layered double hydroxides (LDH) lattice, was also identified. Depending on the initial cerium concentration, LDHs with different Ce(III)/Ce(IV) ratios were produced, which had Lewis acidic and basic characters, respectively. However, the acid–base character of these LDHs was related to the actual Ce(III)/Ce(IV) molar ratios, resulting in significant differences in their catalytic performance. The as-prepared structures enabled varying degrees of transfer hydrogenation (Meerwein–Ponndorf–Verley MPV reduction) of biomass-derived carbonyl compounds to the corresponding alcohols without the collapse of the original lamellar structure of the LDH. The catalytic markers through the test reactions were changed as a function of the amount of Ce(III) centers, indicating the active role of Ce(III)–OH units. However, the cooperative interplay between the active sites of Ce(III)-containing specimens and the hydroxyl vacancies was necessary to maximize catalytic efficiency, pointing out that Ce-containing LDH is a potentially commercial solid FLP catalysts. Furthermore, the crucial role of the surface hydroxyl groups in the MPV reactions and the negative impact of the interlamellar water molecules on the catalytic activity of MgAlCe-LDH were demonstrated. These solid FLP-like catalysts exhibited excellent catalytic performance (cyclohexanol yield of 45%; furfuryl alcohol yield of 51%), which is competitive to the benchmark Sn- and Zr-containing zeolite catalysts, under mild reaction conditions, especially at low temperature (T= 65 °C).

Herpes zoster (HZ) causes considerable pain and distress, and γ-Aminobutyric acid (GABA) and its derivatives are assumed to control this, but the available data are inconsistent. This meta-analysis and systematic review aimed to assess the effectiveness of GABA derivatives in the prevention of acute herpetic pain. The metaanalysis was conducted following the PRISMA guidelines using PICO format, registered in PROSPERO number CRD42018095758. PubMed, Web of Science, Ovid, Scopus, and EMBASE databases were searched. Records were included if they were randomized controlled trials of patients undergoing HZ infection, investigating the effect of GABA derivatives versus placebo in the treatment of HZ pain. Eligible trials were evaluated for the risk of bias. Then data were extracted and analysed. The number of patients with observed presence of pain after treatment was used to calculate odds ratio in a random effect model with the DerSimonian-Laird estimator. The I2 statistic was analysed for heterogeneity. The potential risk of bias was measured using Egger’s regression test. The meta-analysis included three randomized controlled trials with a total of 297 patients. The incidence of acute HZ pain events for GABA group was significantly lower compared to placebo group,18/148 vs 44/149, respectively (OR = 0.36; 95% CI = 0.14 to 0.93; Z = 2.11; P = 0.035), Egger’s test yielded P = 0.308. In conclusion, the present meta-analysis demonstrates that GABA derivatives reduce the incidence of acute herpetic pain. However, additional, well-designed randomized clinical trials are needed to determine their dose- and time-dependency regarding this symptom.

Background: Effective and selective oral rinses are required in the daily medical and dental practice. Currently mouthwashes used have substantial side effects. Objectives: Our aim was to evaluate the efficacy of chlorine dioxide-containing mouthwashes in comparison with other previously established mouth rinses in healthy adults using oral hygiene indices. Methods: This work was registered in PROSPERO (CRD42018099059) and carried out using multiple databases and reported according to the PRISMA statement. The search terms used were “chlorine dioxide” AND “oral”, and only randomised controlled trials (RCTs) were included. The primary outcome was the alteration of the plaque index (PI), while the secondary outcomes were the gingival index (GI) and bacterial counts. For the risk of bias assessment, the Cochrane Risk of Bias Tool was used. Statistical analysis for data heterogeneity was performed by Q-value and I2-tests. Results: 364 articles were found in the databases. After the selection process, only five RCTs were eligible for meta-analysis. Data heterogeneity was low. There were no statistical differences in effectiveness between chlorine dioxide and other effective mouth rinses in PI (0.720±0.119 vs 0.745±0.131; 95%; confidence intervals (CIs): 0.487-0.952 vs 0.489-1.001, respectively) and GI (0.712±0.130 vs 0.745±0.131; 95% CIs: 0.457–0.967 vs 0.489– 1.001, respectively) and also in bacterial counts. Conclusion: Chlorine dioxide reduces both plaque and gingival indices and bacterial counts in the oral cavity similar to other routinely used oral rinses, however, the evidence supporting this outcome is very limited. Therefore, further large scale RCTs are needed to decrease the risk of bias.

Thermo-catalytic bio-SNG (CH4) production is one of the useful tools for converting waste to gaseous fuels through CO2conversion. To abundant properly, however, efficient, robust and cost-effective catalysts would be required. Bimetallic systems based on transition metals seem to be promising candidates for this task. The CoCu bimetallic system with in-situ generated interfaces was synthesized and used as a catalyst for CO2methanation. The in-depth analysis of the structure-activity-selectivity relationships involving XRD, (NAP-)XPS, EXAFS and TEM-EDX revealed that the co-existence of Co0, CoO, and Cu0in the proper distribution on the surface can ensure the selective production of methane. To fine-tune the surface composition of the bimetallic systems, a systematic alteration of the Cu:Co ratio in the precursor spinel structures must be performed. Cu0.4Co2.6O4derivative, stabilizing subsurface Cu(I)–O specimen, showed the best performance with high activity (12,800 nmol g–1s–1) and a remarkable selectivity of 65–85% for methane in a wide temperature range (250–425 °C). In studying the mechanistic aspects of methanation, it has been shown that the hydrogenation of active carbon at the surface or below the surface is the key step for the production of methane. So far, this cobalt-catalyzed sub-step has been proposed in catalytic Fischer-Tropsch syntheses.

Optimum conditions were searched for the synthesis of Cu(II)Cr(III)-L(ayered)D(ouble)H(ydroxide), then the intercalation and catalytic properties were studied. For the optimization, the molar ratio of the metal ions, pH, temperature and ageing time were systematically varied. Applying this LDH as the host, the anionic form of l-proline was intercalated into the interlayer space with the direct anion-exchange method. For the structural characterization of the pristine and the intercalated products, powder X-ray diffractometry, IR spectroscopy, scanning and transmission electron microscopies as well as thermal methods were used. The catalytic properties were investigated in the oxidation of allylic alcohol. The reaction parameters such as the solvent, oxidant and the catalysts treatment were varied.

Mn(II)-containing layered double hydroxides were prepared having the Mn(II) ions in various positions (i) on the layers as dopants, (ii) in the layers as their constituents and (iii) among the layers in the form of intercalated Mn(II) amino acid complexes. The substances were characterized by a range of instrumental methods (XRD, SEM, SEM–EDX) to indicate the positions of the Mn(II) ions. The catalytic activities of the composites were studied in the Ullmann-type etherification reaction. All materials promoted the reaction actively. However, only those having the Mn(II) ions in the structure of the LDH samples, the latter two, proved to be recyclable, i.e. they were real catalysts; the activity of the one prepared by doping deteriorated rapidly on reuse.

Boron-containing CaAl-layered double hydroxides (LDHs) were prepared by milling, as well as the dehydration–rehydration and the anion-exchange methods. The substances obtained were structurally characterized by powder X-ray diffraction measurements, scanning electron microscopy and infrared spectroscopy. Various borate species could be introduced among the layers and/or the outer surface of the CaAl-LDH. The materials were tested as catalysts in the Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam in the liquid phase, at 373 K. Two of them, the samples prepared by dehydration–rehydration and anion exchange, proved to be active, selective and recyclable catalysts, while the one made by the mechanochemical method was practically inactive. The catalytic activity was tied to intercalated and/or surface-bonded triborate and tetraborate species.

Development of novel biodegradable and biocompatible scaffold materials with optimal characteristics is important for both preclinical and clinical applications. The aim of the present study was to analyze the biodegradability of poly(aspartic acid)-based hydrogels, and to test their usability as scaffolds for MG-63 osteoblast-like cells. Poly(aspartic acid) was fabricated from poly(succinimide) and hydrogels were prepared using natural amines as cross-linkers (diaminobutane and cystamine). Disulfide bridges were cleaved to thiol groups and the polymer backbone was further modified with RGD sequence. Biodegradability of the hydrogels was evaluated by experiments on the base of enzymes and cell culture medium. Poly(aspartic acid) hydrogels possessing only disulfide bridges as cross-links proved to be degradable by collagenase I. The MG-63 cells showed healthy, fibroblast-like morphology on the double cross-linked and RGD modified hydrogels. Thiolated poly(aspartic acid) based hydrogels provide ideal conditions for adhesion, survival, proliferation, and migration of osteoblast-like cells. The highest viability was found on the thiolated PASP gels while the RGD motif had influence on compacted cluster formation of the cells. These biodegradable and biocompatible poly(aspartic acid)-based hydrogels are promising scaffolds for cell cultivation.

Functional reconstruction of lost tissue by regenerative therapy of salivary glands would be of immense benefit following radiotherapy or in the treatment of Sjogren's syndrome. The purpose of this study was to develop primary cultures of human salivary gland cells as potential regenerative resources and to characterize their acinar/ductal phenotype using electrophysiological measurements of ion transport. Human salivary gland cultures were prepared either from adherent submandibular gland cells (huSMG) or from mixed adherent and nonadherent cells (PTHSG) and were cultivated in Hepato-STIM or minimum essential medium (MEM). Expression of key epithelial marker proteins was determined by quantitative reverse transcription polymerase chain reaction (RT-PCR). Transepithelial electrical resistance (TER) was monitored following seeding the cells on Transwell membranes. Transepithelial ion transport was estimated by short-circuit current (Isc) measurements in an Ussing chamber. Both huSMG and PTHSG cells showed epithelial characteristics when cultivated in Hepato-STIM, while fibroblast-like elements dominated in MEM. Compared to intact tissue, cultivation of the cells resulted in substantial decreases in AQP5 and NKCC1 expression and moderate increases in claudin-1 and ENaC expression. Both cultures achieved high TER and transepithelial electrolyte movement in Hepato-STIM, but not in MEM. The Iscwas substantially reduced by basolateral Cl−and bicarbonate withdrawal, indicating the involvement of basolateral-to-apical anion transport, and by the blockade of apical ENaC by amiloride, indicating the involvement of apical-to-basolateral Na+transport. An almost complete inhibition was observed following simultaneous ENaC block and withdrawal of the two anions. Iscwas enhanced by either apical adenosine triphosphate (ATP) or basolateral carbachol application, but not by forskolin, confirming the expected role of Ca2+-activated regulatory pathways in electrolyte secretion. Inhibition of basolateral NKCC1 by bumetanide reduced the response to ATP, indicating the active involvement of this transporter in Cl−secretion. In conclusion, we have demonstrated that both PTHSG and huSMG primary cultures cultivated in Hepato-STIM form two-dimensional monolayers in vitroon permeable supports and achieve active vectorial transepithelial electrolyte transport. The presence of both basolateral-to-apical anion fluxes and an apical-to-basolateral Na+flux indicates both acinar and ductal characteristics. With further refinement, this model should provide a firm basis for new interventions to correct salivary gland dysfunction.

In this work, the syntheses of covalently grafted C-protected Cu(II)–amino acid (methylesters of l-histidine and l-cystine) uniform and mixed ligand complexes with two different amino acid esters are described using chloropropylated silica gel as the support. The conditions of the syntheses were systematically altered. The structural features of the substances obtained were studied by the Kjeldahl method, ICP-MS, X-ray absorption and mid/far infrared spectroscopies. The superoxide dismutase-like activities of the materials were determined in a biochemical test reaction and these substances were also tested as catalysts in the oxidation of cyclohexene. It was possible to prepare metal ion-amino acid complexes grafted with covalent bonds onto the supports. All the covalently anchored materials displayed superoxide dismutase-like activity and most of them were active in the oxidation of cyclohexene, providing the epoxide with high selectivity.

Surface quality development on series of metal samples was investigated using a new Ar ion milling apparatus. The surface quality of samples was characterized by the image quality (IQ) parameter of the electron backscatter diffraction (EBSD) measurement. Ar ion polishing recipes have provided to prepare a surface appropriate for high quality EBSD mapping. The initial surfaces of samples were roughly grinded and polished. High quality surface smoothness could be achieved during the subsequent Ar ion polishing treatment. The optimal angles of Ar ion incidence and the polishing times were determined for several materials.

Surface preparation for electron backscatter diffraction (EBSD) measurements requires a lot of time and experience. We chose a lath martensitic iron based alloy to demonstrate the efficiency of ion polishing techniques. The average image quality (IQ) values from the EBSD measurements were assigned to be the characteristic parameter for surface goodness. The ideal ion sputtering time and the angle of incidence were determined, and the corresponding inverse pole figure (IPF) and IQ maps were compared to the mechanical polishing treatment.

Guest molecules in layered double hydroxides (LDHs) may be located both on the surface and in the interlayer gallery. In this work, a comparative study of various IR spectroscopic methods coupled with X-ray diffraction (XRD) is presented, which makes it possible to distinguish between the two possibilities. During the experimental work, first, CaAl-LDHs intercalated with nitrate/carbonate ions were transformed to d-gluconate- and benzoate-containing solids. Depending on the initial interlayer ion, the organic molecules may end up between the layers and/or on the surface of the LDH. The IR spectra of the specimens were recorded by using four different techniques, which are different in their penetration depth (photoacoustic spectroscopy (PAS), attenuated total reflectance (ATR), diffuse reflectance IR spectroscopy (DRIFTS), and wide angle diffuse reflectance (WA-DRIFTS)). By comparing the spectra obtained, the anionic species that are surface adsorbed to LDHs were proven to be distinguishable from those intercalated in the interlayer gallery. PAS spectra are shown to provide information about interlamellar and bulk compounds. The screening of the surface species could be performed using the WA-DRIFTS technique, while ATR and DRIFTS are capable of detecting both the surface and the bulk anions residing in the top few layers.

Abstract

Nowdays semiconductor manufacturing technology approaches its limit of miniaturization. There is a need for devices with low impact of miniaturization on its functionality. We present here simulation results of double-gate MOSFET devices with variable silicon channel width. Effects of segmentation is shown in characteristics of devices.

In unserer Studie versuchen wir die am 13.05.2002 in Nagykónyi (Ungarn) in den Abendstunden entstandene Sturzfl ut (engl. ,,flash flood") zu rekonstruieren und zu modellieren. Zirka zwischen 18:30 und 19:15, innerhalb von 45 Minuten ergoss sich ein heftiger Regenfall auf das geforschte Gebiet. Wegen den Lokalverhältnissen strömte eine Überflutung in der sich in einem Erosions- und Derasionstal befindenden Bársonystrasse. Da dieses Ereignis zu den ersten ähnlichen Katastrophen der letzen 10 Jahre gehörte, wurde leider kaum dokumentiert. Darum können die entstandenen Ergebnisse nur unter entsprechenden Schranken richtig gedeutet werden, dürfen als Tatsache nicht angenommen werden. Wegen der in dem Klima von Ungarn erscheinenden extremen Wetterlage werden das Erforschen und das Kennenlernen dieser früher kaum gekannten Erscheinung immer wichtiger. Von der hydrometeorologischen Lage hinaus wird das Entstehen und Schädigung der Sturzfluten von den lokalen Eigenheiten und Aspekten beeinflusst. Nach den zur Verfügung stehenden auf dieses Gebiet bezogenen Radaraufnahmen (MRL-5) fiel 21 mm Niederschlag auf das erforschte Einzugsgebiet nach der Lokalzeit am Nachmittag zwischen 18 und 20 Uhr, aber nach der Messung einiger Einwohner hätte es 54 sogar 92 mm sein können. Nach unserer Messung mit dem Modell HEC-HMS 3.2. hätte die Gesamtwasserergebigkeit der Wasserfl ut zwischen 2.8 und 7 m3/s stehen können. Die Versammlungszeit des Wassers lag bei mehr als 46 Minuten. Nach unserer Meinung führten die ungewöhnliche hydrometeorologische Lage und die Lokalverhältnisse (Geomorphologie, Bebauung, Gebietsveränderung) zusammen zu der Katastrophe der Ortschaft.

Abstract: Bisphosphonates are widely used as therapeutic agents in bone disorders including cancer metastasis due to their osteoclast inhibitory effect. Recent data shows that bisphosphonates may also induce bone-building by stimulating osteoblast activity. Clinical observations, however, have revealed that bisphosphonates may cause necrosis in the oral cavity which questions their usefulness in bone regeneration during the consolidation of inorganic implants. Here we report the investigation of bone neogenesis following chronic amine bisphosphonate (Zometa®) treatment in a novel experimental model, using the rat tail vertebra as a support. This method involves (1) implantation of titan screw into the tail vertebrae, (2) systemic bisphosphonate treatment and (3) quantitative biophysical measurements which mirrors consolidation of implant, i.e. strength of fixation and changes in newly formed bone architecture using micro Computer Tomograph (micro-CT). The degree of fixation of titan implants (osseointegration) increased by 36% on the effect of Zometa and the structure of newly formed bone became robust. The mass of new bone increased 3.1-fold at 6 weeks of regeneration, as compared to controls. Thus, Zometa®, a potent aminobisphosphonate used in therapy of cancer metastases, osteoporosis and bone marrow transplantation, significantly increased bone neogenesis and enforced osseointegration of titan implants as measured quantitatively in the rat tail vertebra. Our data support the usefulness of aminobisphosphonates in the rehabilitation of bone loss as well as in improvement osseointegration of implants. We emphasise that this novel method may open up new possibilities for screening the effects of local and systemic treatments.

The human pancreatic duct cell line, HPAF, has been shown previously to secrete Cl−in response to Ca2+-mobilizing stimuli. Our aim was to assess the capacity of HPAF cells to transport and secrete HCO3−.

There is no effective treatment for the loss of functional salivary tissue after irradiation for head and neck cancer or the autoimmune disease Sjögren's syndrome. One possible approach is the regeneration of salivary glands from stem cells. The present study aimed to investigate whether small pieces of human submandiblar gland tissue contain elements necessary for the reconstruction of salivary rudiments in vitrovia acinar and ductal cell differentiation. Primary submandibular gland (primary total human salivary gland; PTHSG) cells were isolated from human tissue and cultured in vitrousing a new method in which single cells form an expanding epithelial monolayer on plastic substrates. Differentiation, morphology, number, and organization of these cells were then followed on basement membrane extract (BME) using RNA quantitation (amylase, claudin-1 (CLN1), CLN3, kallikrein, vimentin), immunohistochemistry (amylase and occludin), viability assay, and videomicroscopy. On the surface of BME, PTHSG cells formed acinotubular structures within 24 h, did not proliferate, and stained for amylase. In cultures derived from half of the donors, the acinar markers amylase and CLN3 were upregulated. The PTHSG culture model suggests that human salivary gland may be capable of regeneration via reorganization and differentiation and that basement membrane components play a crucial role in the morphological and functional differentiation of salivary cells.

A self-consistently coupled three-dimensional dynamical model is presented for the first time, to our knowledge, to simulate noncircular vertical-cavity surface-emitting lasers. The electric, thermal, and optical processes are formulated using finite-volume-method discretization adopted on a unified mesh consisting of prism elements. Steady-state and dynamical calculations are shown for specially designed structures. An efficient numerical treatment enables one to perform large-scale calculations on single computers.

ATP is an extracellular regulator in numerous physiological and pathologic processes. Recently, 7 different subtypes of purinoceptors were identified on either the basolateral or the luminal membrane of pancreatic duct cells. However, the in vivo regulatory role of ATP in pancreatic function has not been established. We investigated the possible regulatory role of endogenous ATP in pancreatic function by measuring ATP concentrations and ATPase activity in pancreatic juice obtained from anesthetized rats and guinea pigs and from human patients undergoing endoscopy. Juice was collected from the main pancreatic duct in rats and guinea pigs under basal conditions or during stimulation with CCK, bombesin, or secretin. In guinea pigs, CCK, bombesin, and secretin did not affect ATP output, although they did stimulate fluid secretion. ATPase activity in the juice was evaluated by measuring the rate of hydrolysis of added ATP. Consistent with the low ATP concentrations in rat pancreatic juice, we found high levels of ATPase activity in this species. This was confirmed by HPLC, which also showed the metabolites of ATP hydrolysis. Ecto-ATPase activity was demonstrated by enzyme histochemistry in both the pancreatic acini and ducts in rats, but it was not detectable in guinea pigs and humans. These differences in ATP levels and ATPase expression may indicate significant species differences in the purinergic regulation of pancreatic secretion.

The diagnosis of analgesic nephropathy has improved significantly with modern imaging techniques. We reviewed a large portion of the Hungarian dialysis population to obtain additional insight into the problem.

AbstractBackground:Symptomatic dialysis hypotension (DH) continues to be a common problem. By comparing patients prone and resistant to DH, several dialysis session and patient related characteristics have been identified that confer susceptibility to DH. Less is known, however, about the comparison of patients with frequent and only occasional DH. The aim of the study was to compare clinical and dialysis-session- (complicated by hypotension) related data between those with frequent (fDH) and those with occasional dialysis hypotension (oDH). Methods:Nine hundred and fifty-eight patients at 11 dialysis units were followed for 10 months and characteristics of patients with fDH (≥10 hypotensive events necessitating medical intervention) (n = 96) were compared to that of patients with oDH (1 or 2 events/10 months) (n = 130). Significant and independent predictors of fDH were obtained by multivariate logistic regression. Results:Significant differences between fDH vs. oDH patients were older age (64.4 vs. 56.9 years, p < 0.001), more females (66 vs. 46%, p < 0.005) in fDH. More fDH patients had diabetes (27 vs. 15%, p < 0.05) and less had glomerulonephritis (15 vs. 35%, p < 0.001) as the cause for ESRD. Coronary artery disease (68 vs. 50%, p < 0.01) and long-acting nitrate treatment (51 vs. 30%, p < 0.001) was more frequent while treatment with ACEI (33 vs. 48%, p < 0.05) or Ca-channel blockers (40 vs. 53%, p < 0.05) were less frequent in patients with fDH. Patients with fDH had higher serum phosphorus levels (1.99 vs. 1.79 mmol, p < 0.005). Dialysis session related data were similar but the hypotensive episode occurred earlier during dialysis in fDH (136 vs. 156 min, p < 0.01). In multivariate analysis, significant independent predictors of fDH were older age (OR = 1.04 [1.02–1.07]), lack of glomerulonephritis as renal diagnosis (2.63 [1.18–5.87]), high phosphorus levels (5.0 [2.45–10.0]), lack of use of Ca-channel blockers (2.09 [1.12–3.91]), and the use of nitrates (2.38 [1.24–4.55]). Conclusion:Features of the dialysis sessions complicated by DH seem to be similar between patients with fDH and oDH, while patient characteristics such as older age, renal diagnosis other than glomerulonephritis, higher serum phosphorus levels, use of nitrates, and lack of use of calcium channel blockers are significantly and independently associated with fDH.Copyright © 2002 S. Karger AG, Basel

1HCO3−secretion was investigated in interlobular duct segments isolated from guinea‐pig pancreas using a semi‐quantitative fluorometric method. Secretagogue‐induced decreases in intracellular pH, following blockade of basolateral HCO3−uptake with a combination of amiloride and DIDS, were measured using the pH‐sensitive fluoroprobe BCECF. Apparent secretory HCO3−fluxes were calculated from the initial rate of intracellular acidification.2In the presence of HCO3−, stimulation with secretin (10 nm) or forskolin (5 μm) more than doubled the rate of intracellular acidification. This effect was abolished in the absence of HCO3−. It was also abolished in the presence of HCO3−when DIDS and NPPB were applied to the luminal membrane by microperfusion. We therefore conclude that the increase in acidification rate is a useful index of secretagogue‐induced HCO3−secretion across the luminal membrane.3Secretin, cholecystokinin (CCK) and bombesin each stimulated HCO3−secretion in a dose‐dependent fashion. They evoked comparable maximal responses at about 10 nmand the EC50values were 0.5 nmfor secretin, 0.2 nmfor CCK and 30 pmfor bombesin. Acetylcholine (ACh) was also effective, with a maximum effect at 10 μm.4The stimulatory effect of CCK was blocked completely by the CCK1receptor antagonist devazepide but not by the CCK2receptor antagonist L365,260. The CCK analogue JMV‐180 (Boc‐Tyr(SO3H)‐Nle‐Gly‐Trp‐Nle‐Asp‐phenylethyl ester), which is an agonist of the high‐affinity CCK1receptor but an antagonist of the low‐affinity receptor, also stimulated HCO3−secretion but with a smaller maximal effect than CCK. JMV‐180 partially inhibited the response to a high concentration of CCK but not to a lower concentration, suggesting that both high‐ and low‐affinity states of the CCK1receptor evoke HCO3−secretion.5The stimulatory effect of bombesin was blocked completely by the gastrin‐releasing peptide (GRP) receptor antagonist d‐Phe6‐bombesin(6‐13)‐methyl ester (BME) but not by the neuromedin B (NMB) receptor antagonist d−Nal−cyclo[Cys−Tyr−d−Trp−Orn−Val−Cys]−Nal−NH2(BIM−23127).6Secretagogue‐evoked fluid secretion was also examined using video microscopy to measure the rate of swelling of ducts whose ends had sealed during overnight culture. Secretin, CCK, bombesin and ACh all evoked fluid secretion with maximal rates of approximately 0.6 nl min−1mm−2, and with concentration dependences similar to those obtained for HCO3−secretion.7We conclude that CCK, bombesin and ACh stimulate the secretion of a HCO3−‐rich fluid by direct actions on the interlobular ducts of the guinea‐pig pancreas and that these responses are mediated by CCK1receptors, GRP receptors and muscarinic cholinoceptors, respectively.

In this study, the α-glucosidase of C. albicans as a potential virulence factor was investigated. We compared the intracellular and intact-cellular activities of two C. albicans strains: a clinical isolate (FS) and a laboratory mutant (FR) derived from the former. Although the FR strain was superior in all the virulence factors examined as well as in its in vivo virulence, similar intact-cellular α-glucosidase activities were obtained for the two strains. Moreover, the intracellular α-glucosidase activity of the FR strain was lower than that of the FS strain. Making a survey on 20 clinical isolates of C. albicans, the α-glucosidase activities did not correlate with either the extracellular aspartic proteinase (EAP) or the extracellular phospholipase (EP) activities, although we found a correlation between the EAP and EP activities. In conclusion, our experiments do not support the view that the inducible α-glucosidase is a virulence factor of C. albicans.

In this study, the α-glucosidase of C. albicans as a potential virulence factor was investigated. We compared the intracellular and intact-cellular activities of two C. albicans strains: a clinical isolate (FS) and a laboratory mutant (FR) derived from the former. Although the FR strain was superior in all the virulence factors examined as well as in its in vivo virulence, similar intact-cellular α-glucosidase activities were obtained for the two strains. Moreover, the intracellular α-glucosidase activity of the FR strain was lower than that of the FS strain. Making a survey on 20 clinical isolates of C. albicans, the α-glucosidase activities did not correlate with either the extracellular aspartic proteinase (EAP) or the extracellular phospholipase (EP) activities, although we found a correlation between the EAP and EP activities. In conclusion, our experiments do not support the view that the inducible α-glucosidase is a virulence factor of C. albicans.

In this study, the α-glucosidase of C. albicans as a potential virulence factor was investigated. We compared the intracellular and intact-cellular activities of two C. albicans strains: a clinical isolate (FS) and a laboratory mutant (FR) derived from the former. Although the FR strain was superior in all the virulence factors examined as well as in its in vivo virulence, similar intact-cellular α-glucosidase activities were obtained for the two strains. Moreover, the intracellular α-glucosidase activity of the FR strain was lower than that of the FS strain. Making a survey on 20 clinical isolates of C. albicans, the α-glucosidase activities did not correlate with either the extracellular aspartic proteinase (EAP) or the extracellular phospholipase (EP) activities, although we found a correlation between the EAP and EP activities. In conclusion, our experiments do not support the view that the inducible α-glucosidase is a virulence factor of C. albicans.

In this study, the α-glucosidase of C. albicans as a potential virulence factor was investigated. We compared the intracellular and intact-cellular activities of two C. albicans strains: a clinical isolate (FS) and a laboratory mutant (FR) derived from the former. Although the FR strain was superior in all the virulence factors examined as well as in its in vivo virulence, similar intact-cellular α-glucosidase activities were obtained for the two strains. Moreover, the intracellular α-glucosidase activity of the FR strain was lower than that of the FS strain. Making a survey on 20 clinical isolates of C. albicans, the α-glucosidase activities did not correlate with either the extracellular aspartic proteinase (EAP) or the extracellular phospholipase (EP) activities, although we found a correlation between the EAP and EP activities. In conclusion, our experiments do not support the view that the inducible α-glucosidase is a virulence factor of C. albicans.

In this study, the α-glucosidase of C. albicans as a potential virulence factor was investigated. We compared the intracellular and intact-cellular activities of two C. albicans strains: a clinical isolate (FS) and a laboratory mutant (FR) derived from the former. Although the FR strain was superior in all the virulence factors examined as well as in its in vivo virulence, similar intact-cellular α-glucosidase activities were obtained for the two strains. Moreover, the intracellular α-glucosidase activity of the FR strain was lower than that of the FS strain. Making a survey on 20 clinical isolates of C. albicans, the α-glucosidase activities did not correlate with either the extracellular aspartic proteinase (EAP) or the extracellular phospholipase (EP) activities, although we found a correlation between the EAP and EP activities. In conclusion, our experiments do not support the view that the inducible α-glucosidase is a virulence factor of C. albicans.

The present study was carried out to examine basic science teaching in dentistry in Central/Eastern Europe, and compare the situation with the EU. In order to collect the necessary data, a questionnaire has been sent to 25 dental schools of the region and 14 schools from 8 countries responded. According to the data obtained, the number of hours devoted to basic sciences and medical clinical sciences together are 2206 in Central/Eastern Europe, and 1416 in the EU. In the case of dental clinical subjects, the difference in the number of hours is just the opposite, much higher in the EU. Thus, for the Central‐European region there are two real alternative ways of convergence to western Europe. One option is to decrease the level of basic science and medical science teaching and use the free capacity to increase the weight of dental clinical subjects in the curriculum. The other option is to leave the subjects that are at high levels as they are, and increase significantly the number of hours of the whole curriculum. It seems important to promote the convergence between Central/Eastern Europe and the EU. The EU has to define the trends of the next few decades and the Central/Eastern European countries should converge in this direction.