Pigmentation of the rainbow trout (Oncorhynchus mykiss) with oil-extracted astaxanthin from the langostilla (Pleuroncodes planipes)

The purpose of this contribution is to inform about the activities of the local ethics commission established at one of our largest teaching (University) hospitals. In 1995 the following priorities were recognized: studying international ethical standards of research involving human subjects and strictly adhering to them; bilingual administrative agenda in Czech and English; enforcing the patients' rights in health care and emphasizing them in education of medics and other students of health related disciplines; stimulating effective communication between doctors, other health care workers and lay persons in the commission as well as between the members of the commission and authors of research projects applying for ethical evaluation. Since 1993 the commission has been revising and storing in the archives more than 600 research projects. In 1996, 181 new research projects were reviewed, which is 35% more than in 1995. Approval was granted in 154 cases (85.08%), 3 cases (1.66%) were rejected, 15 cases (8.29%) approved on condition of complying with the recommendations of the commission, 6 cases (3.31%) recommended for another commission, and in 3 cases reviewing the project was postponed for lack of necessary data. The members of the commission agree that the future activities should lead to forming a broader group of consultants of the commission and other professional and lay people interested in clinical ethics. According to their meaning, legislation concerning ethical commissions in the Czech Republic, including material and financial support and administrative help, is urgently needed.     

Attrition of spherical electrode carbon particles during batch fluidized combustion

Spherical electrode carbon particles prepared from carbon rods of dry cell batteries have been used to study the attrition behaviour in a bubbling fluidized bed combustor. Experiments have been conducted in a 40 mm I.D. and 1 m high fluidized bed combustor operated at 1 m/s superficial velocity. The bed was operated with nitrogen and with two different oxygen concentrations at 850°C to study the effect of combustion on attrition of these particles. The experimental technique used allowed the time resolution of attrited fines generation, providing detailed curves of attrition rates as a function of time. Attrition rate constants have been evaluated. Results show an enhancement of attrition due to combustion even for spherical, homogeneous and smooth particles.     

How oxide carriers affect the reactivity of V2O5 catalysts in the oxidative dehydrogenation of propane

The catalytic pattern of several oxide carriers (MgO, Al₂O₃, ZrO₂, TiO₂, SiO₂, HY zeolite) and supported V₂O₅ (4.7–5.3 wt%) catalysts in the oxidative dehydrogenation of propane to propylene (PODH) has been comparatively investigated. The fundamental role of the oxide support on both reducibility and reactivity of vanadia catalysts has been assessed. A direct relationship between the specific surface activity of oxide carriers and that of vanadia catalysts is discussed. The inverse relationship between the specific activity and the onset temperature of reduction marks the prevailing redox behaviour of V₂O₅ catalysts in the PODH reaction. This revised version was published online in July 2006 with corrections to the Cover Date.     

Selective partial oxidation of light paraffins with hydrogen peroxide on thin-layer supported Nafion-H catalysts

Thin-layer carbon supported Nafion-H catalysts were found to be active and highly selective (S>98%) for the partial oxidation of C₁-C₃ alkanes, in a three phase catalytic membrane reactor (3PCMR), under mild conditions and in the presence of H₂O₂. The influences of the catalyst teflon loading and H₂O₂ concentration on the reaction rate have been evaluated. A reaction pathway, based on the electrophilic hydroxylation of the C-H bond of alkanes with protonated hydrogen peroxide (H₃O ₂ ⁺ ), is discussed.     

Innovative Membrane-Based Catalytic Process for Environmentally Friendly Synthesis of Oxygenates

Synthesis of liquid oxygenates from light alkanes (C₁--C₃) is achieved in a multifunctional three-phase catalytic membrane reactor (3PCMR) operating under mild conditions (T_R, 80-120 °C; P_R, 140 kPa). The features of superacid catalytic membranes mediated by the Meⁿ⁺/H₂O₂ Fenton system in activating C₁-C₃ alkanes are presented. The effect of operating conditions ([H₂O₂], [Meⁿ⁺]) on the catalyst activity is outlined. A general reaction pathway accounting for the activation of the CH bond of the alkane molecule on the superacid sites and the subsequent reaction of the activated alkane with primary reactive intermediates, generated from the Meⁿ⁺/H₂O₂ system, is proposed. The suitability of the 3PCMR in enabling simultaneous reaction and product separation is discussed.     

Rhodium‐Catalyzed Enantioselective Hydrogenation of (E)‐Enol Acetate Acids

The novel rhodium complex [Rh(S)‐Phanephos(cod)]‐catalyzed hydrogenation of disubstituted (E)‐enol acetate carboxylic acids is reported. The catalytic cycle works under 30 bar of hydrogen under conventional heating giving different 3‐acetoxy‐2,3‐disubstituted carboxylic acids with ee ≥90%. Hydrogenation occurred also under microwave dielectric heating without eroding the enantioselectivity but improving the overall efficiency of the process. With microwaves, hydrogen pressure and reaction time required for complete hydrogenation dropped to 5 bar and 30 min, respectively. The best performance of this catalyst under microwave irradiation was TON 100, TOF 196 h⁻¹ with ee 99% on a 6‐g scale.     

Tailoring Effective FeOx/SiO2 Catalysts in Methane to Formaldehyde Partial Oxidation

A preparation method of highly effective methane to formaldehyde partial oxidation (MPO) FeO_x/SiO₂ catalysts (Fe 0.09--0.43 wt%) is reported, based on adsorption-precipitation (ADS/PRC) of Fe^II ions under controlled conditions. The performance of ADS/PRC catalysts in the MPO reaction at 650 °C has been compared with that of conventional systems prepared by incipient wetness (INC/WET) of silica carriers with aqueous solutions of Fe^III. The ADS/PRC method, likely enabling a higher dispersion of the active phase, provides very effective MPO catalysts featuring CH₄ turnover frequency (TOF) and HCHO productivity (STY_HCHO) values larger than those of the counterpart INC/WET systems.     

Transient Surface Processes of Storage and Conversion of NOx Species on Pt–Me/Al2O3 Catalysts (Me = Ba,Ce, Cu)

The transient reactivity and surface phenomena of storage and conversion of NO _x species on Pt(1%)–Me/Al₂O₃ catalysts, where Me = Ba, Ce and Cu, were studied by the RWF (rectangular wavefront) method. The Me component has a relevant influence on the processes of surface storage and transformation. The reduction of NO _x by propene in the presence of oxygen is promoted by adding Cu to a Pt/Al₂O₃ catalyst, while cerium promotes transient conversion of NO in the absence of propene, but inhibits the reduction of NO _x in the presence of propene. Copper is suggested to be a promising element to add together with Ba for new NO _x storage-reduction catalysts due to its capacity to act both as a storage element and as promoter for NO _x reduction.     

Update on the Diagnostic Pitfalls of Autopsy and Post-Mortem Genetic Testing in Cardiomyopathies

Inherited cardiomyopathies are frequent causes of sudden cardiac death (SCD), especially in young patients. Despite at the autopsy they usually have distinctive microscopic and/or macroscopic diagnostic features, their phenotypes may be mild or ambiguous, possibly leading to misdiagnoses or missed diagnoses. In this review, the main differential diagnoses of hypertrophic cardiomyopathy (e.g., athlete’s heart, idiopathic left ventricular hypertrophy), arrhythmogenic cardiomyopathy (e.g., adipositas cordis, myocarditis) and dilated cardiomyopathy (e.g., acquired forms of dilated cardiomyopathy, left ventricular noncompaction) are discussed. Moreover, the diagnostic issues in SCD victims affected by phenotype-negative hypertrophic cardiomyopathy and the relationship between myocardial bridging and hypertrophic cardiomyopathy are analyzed. Finally, the applications/limits of virtopsy and post-mortem genetic testing in this field are discussed, with particular attention to the issues related to the assessment of the significance of the genetic variants.     

Degradation of 5‐Hydroxymethylfurfural in Honey

ABSTRACT: 5‐Hydroxymethylfurfural (HMF) is the most important intermediate product of the acid‐catalyzed dehydration reaction of hexoses and/or Maillard reaction; furthermore, it is the most used index to evaluate thermal damages or ageing in food products. Usually its degradation reactions, being very slow, are neglected. This study reports the findings concerning the degradation kinetics of HMF, in honeys of different floral origin at a temperature between 25 and 50 °C. The results highlighted higher degradation rates (k_{HMFdegradation}) compared to the corresponding formation rates (k_HMFformation) in chestnut and citrus samples. Similar k‐values were found in multifloral honey. Moreover, the reaction of HMF degradation was characterized by lower activation energy (E_a) values compared to E_a formation values. The final concentration of HMF in honey, during storage at room temperature, should be ascribed to high sugar concentration. The fluctuation of HMF in honeys could depend on the equilibrium between the accumulation and the degradation processes. This can affect the validity of HMF as storage index in some honeys, above all during the analysis of those honeys whose legislation is too restrictive (citrus) or in chestnut honey analysis where it does not accumulate.