Development of colloidal carbon-based immunochromatographic strip for rapid detection of carbaryl in fruit juices

The differences in lipid content will lead to differences in protein structure and gel properties and it is a nice model system, so our study, based on the production process for Zhongxiang tofu, used soy protein isolate (SPI) as raw material and adopted circular dichroism and Raman spectrum to investigate the influence of different lipid content on protein secondary structure in tofu. Texture profile analysis and differential scanning calorimetry were used to analyze the influence of lipid on gel texture properties and state of water. The interactive mechanism at microscopic level was investigated by means of scanning electron microscopy. The results show that the additional lipid reacted with the soy protein and the lipid became a component of a newly formed molecular membrane. With an increase in added lipid, SPI gel hardness was reduced, while springiness increased. The proportion of α-helix and β-sheet in SPI gel at 16% (w/v) lipid are 4.0 and 26.0%, respectively. The equilibrium water content tended to decrease when lipid content was increased.     

Reaction of N-Acetylcysteine with Cu2+: Appearance of Intermediates with High Free Radical Scavenging Activity: Implications for Anti-/Pro-Oxidant Properties of Thiols

We studied the kinetics of the reaction of N-acetyl-l-cysteine (NAC or RSH) with cupric ions at an equimolar ratio of the reactants in aqueous acid solution (pH 1.4–2) using UV/Vis absorption and circular dichroism (CD) spectroscopies. Cu²⁺ showed a strong catalytic effect on the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical (ABTSr) consumption and autoxidation of NAC. Difference spectra revealed the formation of intermediates with absorption maxima at 233 and 302 nm (ε₃₀₂/Cu > 8 × 10³ M⁻¹ cm⁻¹) and two positive Cotton effects centered at 284 and 302 nm. These intermediates accumulate during the first, O₂-independent, phase of the NAC autoxidation. The autocatalytic production of another chiral intermediate, characterized by two positive Cotton effects at 280 and 333 nm and an intense negative one at 305 nm, was observed in the second reaction phase. The intermediates are rapidly oxidized by added ABTSr; otherwise, they are stable for hours in the reaction solution, undergoing a slow pH- and O₂-dependent photosensitive decay. The kinetic and spectral data are consistent with proposed structures of the intermediates as disulfide-bridged dicopper(I) complexes of types cis-/trans-Cu^I₂(RS)₂(RSSR) and Cu^I₂(RSSR)₂. The electronic transitions observed in the UV/Vis and CD spectra are tentatively attributed to Cu(I) → disulfide charge transfer with an interaction of the transition dipole moments (exciton coupling). The catalytic activity of the intermediates as potential O₂ activators via Cu(II) peroxo-complexes is discussed. A mechanism for autocatalytic oxidation of Cu(I)–thiolates promoted by a growing electronically coupled –[Cu^I₂(RSSR)]_n– polymer is suggested. The obtained results are in line with other reported observations regarding copper-catalyzed autoxidation of thiols and provide new insight into these complicated, not yet fully understood systems. The proposed hypotheses point to the importance of the Cu(I)–disulfide interaction, which may have a profound impact on biological systems.     

Impedance measurement of growth of lactic acid bacteria in the presence of nisin and lysozyme

Effect of nisin (0.500 g/l), lysozyme (0.035 g/l) and the mix of nisin (0.500 g/l) and lysozyme (0.035 g/l) against two nisin-producing lactococci strains, three non-nisin-producing lactococci strains and four lactobacilli strains with antimicrobial activity was determined by the impedimetric method. None of the tested lactococci and lactobacilli strains were inhibited by lysozyme at concentration of 0.035 g/l. Only the nisin-producing lactococci strains were resistant to nisin at 0.500 g/l, the other lactococci and lactobacilli were inhibited by nisin at 0.500 g/l intensively. The mix of lysozyme and nisin displayed a comparable effect to the nisin addition against the used lactococci strains and was very variable depending on the strain of tested lactobacilli. The impedimetric method was shown to be convenient for screening the growth abilities of lactococci and lactobacilli in the presence of antimicrobial components.     

Number and size of lupulin glands,glandular trichomes of hop (Humulus lupulus L.), play a key role in contents of bitter acids and polyphenols in hop cone

Hop (Humulus lupulus L.) inflorescence, commonly known as ‘hop cone’, is valuable for contents of bitter acids, essential oils and polyphenols, used in brewing industry and biomedical application. These compounds are predominantly formed in glandular trichomes, known as ‘lupulin glands’. In this study, we investigated chemical and morphological characteristics of lupulin glands by microscopy and HPLC analyses. Even though no significant correlations were found between lupulin glands and hop cones for contents of alpha and beta bitter acids, polyphenols, all ratios between individual metabolites (alpha/beta acids, X/alpha acids, X/DMX) were highly and significantly correlated. The average number of lupulin glands on bract/bracteole ranged from 115 to 713 with 28.5% of variability. Linear regression analyses confirmed that total volume of lupulin glands and total lupulin glands area on bract/bracteole surface highly correlated with contents of bitter acids and polyphenols in hop cone. Therefore, lupulin glands are unique and exclusive organs responsible for contents of bitter acids and polyphenols in hop cone.     

Uro-gynecologic disorders in female geriatric patients

As geriatric patients those above 60 years of age are described. Incontinence is not necessarily an associated symptom of old age. In women above 60 years 15-30% suffer from urinary incontinence. With advancing age the prevalence rises to more than 40%. The cause of miction trouble must not be sought only in the urogenital tract, where with advancing age under the influence of atrophic processes typical functional and anatomical changes take place, but also in the sphere of the CNS where in geriatric patients may be the cause of impaired continence. A preliminary classification of urinary incontinence may be made already on the basis of a detailed case-history. Data provided by the patient are usually not sufficient and it is necessary to obtain the required information on the character of incontinence by aimed questions. Furthermore it is of interest what sort of medication the patient is taking at the time, incl. medication she take spontaneously. Sometimes after mere discontinuation of certain drug groups complaints can be markedly reduced or completely eliminated. In the case-history we must always focus attention on risk factors associated with incontinence and questions on the abuse of alcohol are also justified. Somatic examination comprises gynaecological examination for evaluation of the anatomical characteristics at rest and during elevated intraabdominal pressure. Functional geriatric examination is the starting point for optimal care of old people. There is a number of functional geriatric tests. For clinical practice due to its straightforward character Barthel's test of basic everyday activities is useful. Urodynamic examination is not essential in geriatric patients. Information obtained in diagnostic processes may serve as a basis for rational therapy of incontinence. Different urodynamic methods are used in case therapy fails or when the anamnestic data are obscure.     

Zum 65. Geburtstag von Hans Heinrich Bosshard

Ohne Zusammenfassung     

Caution when applying eddy current inversion to stress corrosion cracking

This study evaluates the applicability of computer-aided eddy current inversion techniques to the profile evaluation of stress corrosion cracking in Inconel welds. Welded plate specimens, which model head penetration welds of pressurized water reactors, are fabricated; notches and stress corrosion cracks are artificially introduced into the weld metal of the specimens. Eddy current inspections are performed using a uniform eddy current probe driven at frequencies of 10 and 40 kHz. Since weld noise is observed uniformly along the weld line, a simple signal processing is applied to eliminate it. First, the artificial notches are reconstructed and good agreements between reconstructed and true profiles are provided, which demonstrates that the computer-aided eddy current inversion technique can deal with defects in welds. Then, numerical simulations are performed to evaluate the profiles of the stress corrosion cracks. In the numerical simulations, the stress corrosion cracks are modeled as a conductive region with a fixed width of 0.3 mm. The cross-sectional profiles of the cracks are reconstructed from measured eddy current signals directly above and along a crack. Although eddy current signals calculated from the reconstructed profiles agree well with measured ones, the true profiles revealed by destructive testing are found to be very different from the reconstructed ones. Whereas the most plausible reason for the difference is the unexpectedly volumetric profile of the stress corrosion cracks, this study has revealed that computer-aided eddy current inversion techniques that have been used to consider cracks in thin structures would not at this point be directly applicable to those in thick structures. It is also important to know in advance those crack features that can adversely impact accurate crack sizing including whether a detected crack is volumetric or not, namely there are many parallel cracks in a cluster or not.     

Detection of embedded fatigue cracks in Inconel weld overlay and the evaluation of the minimum thickness of the weld overlay using eddy current testing

This study evaluates the applicability of eddy current testing to the detection and sizing of fatigue cracks embedded in Inconel weld overlays. Welded plate specimens, which model head penetration welds and their weld overlays, are fabricated, and fatigue cracks are artificially introduced into the specimens. Eddy current inspections are performed using a uniform eddy current probe driven with 10 kHz, and all of the fatigue cracks are detected with clear signals. Subsequent numerical inversions estimate that the minimum thicknesses of the weld overlays are 1.47, 2.17, and 2.23 mm, whereas true thicknesses revealed through destructive testing are 1.51, 3.25, and 2.10 mm, respectively. Thicknesses are also evaluated using potential drop and ultrasonic testing methods; the results demonstrate that eddy current testing is the most efficient of the three methods.     

Stresses in superconductor during oxygenation

The paper deals with an analytical model of stresses acting in the superconductor YBCO during an oxygenation process to transform the tetragonal lattice of the non-superconductive phase to the orthorhombic lattice of the superconductive phase Accordingly, the oxygenation-induced stresses originate as a consequence of the difference in dimensions of the crystalline lattices. Additionally, critical temperature of the oxygenation process with regard to a crack formation in the superconductor YBCO is derived.     

腐植酸的体外作用

腐植酸被认为在动物喂饲试验中对健康和产率具有整体积极作用,同时颇有争议的是,其也被作为肿瘤的病原学因素之一。我们尝试评价斯洛伐克地区特定来源腐植酸在使用推荐预防剂量时的体外作用。研究其体外的抗氧化性质、对肝线粒体中酶系和非酶系抗氧化防御系统的作用以及对人工培养肿瘤细胞株的作用。我们观察到不论腐植酸是溶解于二甲基亚砜(DMSO)或是直接加入呼吸介质中线粒体悬浮液,在腐植酸给药后超氧化物歧化酶(SOD)活性显著下降。所测定的其他抗氧化酶如谷胱甘肽过氧化物酶(GPx)和谷胱甘肽还原酶(GR),其活性及还原型谷胱甘肽(GSH)的含量与对照组相比并未表现出显著变化。腐植酸对超氧阴离子自由基(O2-·)的抑制率低于其对羟自由基(·OH)的抑制率。6种不同肿瘤细胞株的存活率显示出只有急性T淋巴性白血病细胞株对测试腐植酸敏感。尽管在水溶液中溶解度相对较低,但特定来源腐植酸参与了氧化还原调控。通过夺取自由基,腐植酸重置了抗氧化防御机制。来源于自然资源的腐植酸体外研究结果显示出其作为有前景的免疫增强剂的潜力。