Dynamics of chemical wave segments with free ends

A quite simple but useful approach is performed for the analysis of chemical wave segments with free ends. By integrating a reaction–diffusion system we can obtain an analytical expression to understand the dynamics of the wave segments. This integration can yield qualitative information regarding wave development under an external forcing having feedback or noise effects. We conclude that this wave development is influenced not only by medium excitability but also by wave size.     

Kinetics of Atmospheric Freeze-drying of Apple

We present investigations of the effect of Atmospheric Freeze-Drying kinetics on the quality (dehydration rate, shrinkage, color, and antioxidant properties) of apple cubes. The experimental data are compared with the result of convective and vacuum freeze-drying processes, and suitable operating parameters are determined. The experiments were carried out in an Internet controlled, fully automated heat-pump assisted drying system.     

Inactivation of extremely halophilic hide-damaging bacteria via low-level direct electric current

The presence of proteolytic and lipolytic extremely halophilic bacteria on brine-cured hides reduces the value of the hide as a raw material for leather manufacturing. Every brine curing raceway that produces hide contains a significant number of extremely halophilic bacteria that contaminate almost every hide. The usual brine raceway treatments used to control bacteria during curing do not control halophilic bacteria. The antibacterial effects of passing 0.5-A low level, direct electric current for 30 min on different species of protease, lipase, both protease and lipase producing extremely halophilic bacteria, as well as a mixed population of extremely halophilic bacteria, were examined in liquid media containing organic substances and 25% NaCl. Although the antibacterial effects varied with different extremely halophilic bacterial species, the application of current demonstrated an antibacterial effect within 20 min of treatment of all species tested. A mixed culture of extremely halophilic bacteria was killed within 10 min. It has been demonstrated that treatment time as short as 5 min is sufficient for the total inactivation of protease producing extremely halophilic bacteria of 10⁷ CFU/mL while lipase or lipase and protease producing extremely halophilic bacteria were inactivated within 20 min. It was also found that the temperature and pH of the test medium increased during treatment. The maximum temperature rise was 9 °C, and the pH increased by 4.     

Solid-state structures of 2-(4-hydroxyphenyl)-substituted phenalene-1,3-dione and indan-1,3-dione

The structure of 2-(4-hydroxyphenyl)-substituted indan-1,3-dione and phenalene-1,3-dione is investigated using a combination of solid-state NMR, single crystal X-ray analyses and quantum chemical calculations. It is shown that 2-(4-hydroxyphenyl)-1,3-indandione exists as a diketo tautomer while 2-(4-hydroxyphenyl)-1,3-phenalenedione exists in the enol form.     

The influence of selected metals and halogens on the electronic system of benzoic acid

The influence of halogens and metals on the electronic system of the aromatic ring in lithium, sodium and potassium complexes with p-halogenobenzoic acids has been investigated by means of ¹³C and ¹H NMR, IR and Raman spectroscopy and semi-empirical calculations. It has been shown that ionic potentials and electronegativities of halogens and metals are the main factors responsible for perturbations of the electronic charge distribution in the ring.     

Thermodynamic properties of the N-octylquinolinium bis{(trifluoromethyl)sulfonyl}imide

This work is a continuation of our wide ranging investigation on quinolinium based ionic liquids (ILs). The study includes specific basic characterisation of the synthesized compounds N-octylquinolinium bromide, [OQuin][Br] and N-octylquinolinium bis{(trifluoromethyl)sulfonyl}imide [OQuin][NTf₂] by NMR spectra, elementary analysis and water content. Differential scanning calorimetry (DSC) measurements gave us properties of the pure [OQuin][NTf₂] i.e. melting and glass-transition temperatures, the enthalpy of fusion as well as heat capacity at the glass transition. Densities and viscosities were determined as a function of temperature. The temperature-composition phase diagrams of 10 binary mixtures composed of organic solvent dissolved in the IL: {[OQuin][NTf₂] + aromatic hydrocarbon (benzene, or thiophene, or toluene, or ethylbenzene, or n-propylbenzene), or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol, or 1-dodecanol)} were measured at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (250 to 370) K. For mixtures with benzene and alkylbenzenes, the immiscibility gap in the liquid phase in a low mole fraction of the IL was observed with upper critical solution temperature (UCST) higher than the boiling point of the solvent. In the system with thiophene, the immiscibility gap is lower and UCST was measured. For binary mixtures with alcohols, complete miscibility in the liquid phase was observed for 1-butanol and 1-hexanol. In the systems with longer chain alcohols, the immiscibility gap with UCST was noted. Typical behaviour for ILs was observed with an increase of the chain length of an alcohol the solubility decreases. The well-known NRTL equation was used to correlate experimental (solid + liquid), SLE and (liquid + liquid), LLE phase equilibrium data sets.     

Effects of high pressure treatment on the quality of cooked pork ham prepared with different levels of curing ingredients

The aim of this study was to define the effects of high-pressure treatment (600 MPa, 10 min, 20 °C) on the quality of cooked pork ham prepared with two different levels of curing ingredients in brine. Physical, chemical, microbiological, and sensory tests were performed 24 h after high pressure processing (HPP), as well as after 6 and 8 weeks of storage in refrigerator conditions. The results indicate that HPP causes significant improvement of shelf life of vacuum packed ham, including the samples with reduced level of curing ingredients in brine to 8 weeks in refrigerator conditions (4–6 °C). HPP did not have significant effect on the texture or color of ham. However, it significantly increased the drip loss during storage in the packed samples. This may indicate that HPP has negative effects on water holding capacity of cooked products.     

Diastereoisomers of a prednisolone derivative

The crystal and molecular structures of two synthetic corticosteroid diastereoisomers were determined by X-ray diffraction methods. (22R)-21-acetoxy-16,17-furfurylidenedioxy-11-hydroxy-pregna-1,4-diene-3,20-dione, C₂₈H₃₂O₈, crystallized in the orthorhombic system, space group P2₁2₁2₁,a=6.346(1),b=14.106(2),c=27.901(3) Å, andZ=4. (22S)-21-acetoxy-16, 17-furfurylidenedioxy-11-hydroxy-5 pregna-1,4-diene-3,20-dione ethanolate, C₂₈H₃₂O₈ ·C₂H₅OH, crystallized in the monoclinic system, space group C2,a=20.382(5),b=8.331(1),c=17.346(4)Å, =103.43(2)°, andZ=4. A change of configuration at the C(22) chirality center has influence on the remote parts of the molecules. The long-range effects appear in the ability to form intermolecular hydrogen bonds by different atoms and consequently in the solvation of the (S) diastereoisomer.     

AROMATICITY OF SOME METAL BENZOATES——EFFECT OF METAL SALTS ON THE AROMATIC SYSTEM OF BENZOIC ACID USING IR, RAMAN AND UV SPECTROSCOPIC METHODS

In this paper,the aromaicity of some metal benzoates has been studied us-ing IR,Raman and UV spectroscopic methods.The bond frequencies in IR andRaman spectra of Hg(Ⅰ),Mg and K benzoates are summarised in table 1.Theeffects of Cr(Ⅲ),Fe(Ⅲ),Cu(Ⅱ),etc.on the aromatic system of benzoic acidwere compared.It is found that Cr(Ⅲ)iron(Ⅲ),Ianthanides and Al can stabi-lize this system.