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111.
The study focused on the influence of starch modified by octenyl succinic anhydride (OSA) on the rheological and thermal properties of gluten-free dough containing corn and potato starch with the addition of pectin and guar gum as structure-forming substances. The starch blend used in the original dough recipe was partially (5% to 15%) replaced with OSA starch. The rheological properties of dough samples were determined, and the properties of the resulting bread were analyzed. It was found that the dough samples behaved as weak gels, and the values of storage and loss moduli (G′ and G″, respectively) significantly depended on angular frequency. Various shares of OSA starch in recipes modified dough in different ways, causing changes in its rheological characteristics. The introduction of OSA starch preparations resulted in changes in the bread volume and physical characteristics of the crumb. All the applied preparations caused an increase in bread porosity and the number of pores larger than 5 mm, and there was a parallel decrease in pore density. The presence of OSA starch preparations modified bread texture depending on the amount and type of the applied preparation. The introduction of OSA starches in gluten-free bread formulation caused a significant drop in the enthalpy of retrograded amylopectin decomposition, indicating a beneficial influence of such type of additive on staling retardation in gluten-free bread.  相似文献   
112.
A selective and sensitive method is proposed for the determination of mercury by anodic stripping voltammetry after its preconcentration from the gas phase. Mercury from the sample solution is reduced to elemental Hg by SnCl2 and volatilized by the bubbles of a carrier gas. The gas containing mercury vapour is dried and passed through a capillary onto a gold coated graphite electrode. An anodic stripping voltam-mogram is recorded from 0.1 mol/1 HClO4 + 3 × 10−3 mol/1 HCl solution. The calibration curve is linear from 1 × 10−9 to 4 × 10−8 mol/1 Hg(NO3)2. The absolute detection limit is 0.46 ng Hg. The relative standard deviations for 4 × 10−9 mol/1 and 2 × 10−8 mol/1 Hg(NO3)2 are 9.8% and 6.1%, respectively n = 5).  相似文献   
113.
Total absolute cross sections for electron scattering on hexafluorobenzene, C6F6, and sulfur hexafluoride, SF6, molecules, have been measured as a function of impact energy from 0.6 to 250 eV. The total cross section for C6F6 exhibits a very broad peak stretching from 10 to 100 eV with some weak features near 9.5 and 15 eV superimposed on the peak. Apart from the well-known low-energy resonant structures in the SF6 total cross section function, a new weak resonant feature close to 25 eV has been noticed in the present experiment, in accordance with earlier theoretical calculations.  相似文献   
114.
The addition of 2-amino-1,3,4-thiadiazole derivatives with parallel iodination of differently protected glycals has been achieved using a double molar excess of molecular iodine under mild conditions. The corresponding thiadiazole derivatives of N-glycosides were obtained in good yields and anomeric selectivity. The usage of iodine as a catalyst makes this method easy, inexpensive, and successfully useable in reactions with sugars. Thiadiazole derivatives were tested in a panel of three tumor cell lines, MCF-7, HCT116, and HeLa. These compounds initiated biological response in investigated tumor models in a different rate. The MCF-7 is resistant to the tested compounds, and the cytometry assay indicated low increase in cell numbers in the sub- G1 phase. The most sensitive are HCT-116 and HeLa cells. The thiadiazole derivatives have a pro-apoptotic effect on HCT-116 cells. In the case of the HeLa cells, an increase in the number of cells in the sub-G1- phase and the induction of apoptosis was observed.  相似文献   
115.
Bee products have been known for centuries for their versatile healing properties. In recent decades they have become the subject of documented scientific research. This review aims to present and compare the impact of bee products and their components as antimicrobial agents. Honey, propolis, royal jelly and bee venom are bee products that have antibacterial properties. Sensitivity of bacteria to these products varies considerably between products and varieties of the same product depending on their origin. According to the type of bee product, different degrees of activity were observed against Gram-positive and Gram-negative bacteria, yeasts, molds and dermatophytes, as well as biofilm-forming microorganisms. Pseudomonas aeruginosa turned out to be the most resistant to bee products. An analysis of average minimum inhibitory concentration values for bee products showed that bee venom has the strongest bacterial effectiveness, while royal jelly showed the weakest antibacterial activity. The most challenging problems associated with using bee products for medical purposes are dosage and safety. The complexity and variability in composition of these products raise the need for their standardization before safe and predictable clinical uses can be achieved.  相似文献   
116.
Traditional wastewater purification processes are based on a combination of physical, chemical, and biological methods; however, typical electrochemical techniques for removing pollutants require large amounts of electrical energy. In this study, we report on a process of wastewater purification, through continuous anodic dissolution of iron anode for aerated Cu/Fe galvanic cell in synthetic Na2SO4 wastewater solution. Electrochemical experiments were conducted by means of a laboratory size electrolyzer, where electrocoagulation along with electrooxidation phenomena were examined for wastewater containing Acid Mixture dye. The above was visualized through the employment of electrochemical (cyclic voltammetry and ac impedance spectroscopy techniques) along with instrumental spectroscopy analyses.  相似文献   
117.
Different parts of a plant (seeds, fruits, flower, leaves, stem, and roots) contain numerous biologically active compounds called “phytoconstituents” that consist of phenolics, minerals, amino acids, and vitamins. The conventional techniques applied to extract these phytoconstituents have several drawbacks including poor performance, low yields, more solvent use, long processing time, and thermally degrading by-products. In contrast, modern and advanced extraction nonthermal technologies such as pulsed electric field (PEF) assist in easier and efficient identification, characterization, and analysis of bioactive ingredients. Other advantages of PEF include cost-efficacy, less time, and solvent consumption with improved yields. This review covers the applications of PEF to obtain bioactive components, essential oils, proteins, pectin, and other important materials from various parts of the plant. Numerous studies compiled in the current evaluation concluded PEF as the best solution to extract phytoconstituents used in the food and pharmaceutical industries. PEF-assisted extraction leads to a higher yield, utilizes less solvents and energy, and it saves a lot of time compared to traditional extraction methods. PEF extraction design should be safe and efficient enough to prevent the degradation of phytoconstituents and oils.  相似文献   
118.
The aim of this research was to provide crucial and useful data about the selection of the optimization criteria of supercritical carbon dioxide extraction of alfalfa at a quarter-technical plant. The correlation between more general output, including total phenolics and flavonoids content, and a more specified composition of polar constituents was extensively studied. In all alfalfa extracts, polar bioactive constituents were analyzed by both spectrometric (general output) and chromatographic (detailed output) analyses. Eight specific phenolic acids and nine flavonoids were determined. The most dominant were salicylic acid (221.41 µg g−1), ferulic acid (119.73 µg g−1), quercetin (2.23 µg g−1), and apigenin (2.60 µg g−1). For all seventeen analyzed compounds, response surface methodology and analysis of variance were used to provide the optimal conditions of supercritical fluid extraction for each individual constituent. The obtained data have shown that eight of those compounds have a similar range of optimal process parameters, being significantly analogous for optimization based on total flavonoid content.  相似文献   
119.
Ionizing radiation is a factor that seriously damages cellular mechanisms/macromolecules, e.g., by inducing damage in the human genome, such as 5′,8-cyclo-2′-deoxypurines (cdPus). CdPus may become a component of clustered DNA lesions (CDL), which are notably unfavorable for the base excision repair system (BER). In this study, the influence of 5′S and 5′R diastereomers of 5′,8-cyclo-2′-deoxyadenosine (cdA) and 5′,8-cyclo-2′-deoxyguanosine (cdG) on the uracil-DNA glycosylase (UDG) and human AP site endonuclease 1 (hAPE1) activity has been taken under consideration. Synthetic oligonucleotides containing 2′-deoxyuridine (dU) and cdPu were used as a model of single-stranded CDL. The activity of the UDG and hAPE1 enzymes decreased in the presence of RcdG compared to ScdG. Contrary to the above, ScdA reduced enzyme activity more than RcdA. The presented results show the influence of cdPus lesions located within CDL on the activity of the initial stages of BER dependently on their position toward dU. Numerous studies have shown the biological importance of cdPus (e.g., as a risk of carcinogenesis). Due to that, it is important to understand how to recognize and eliminate this type of DNA damage from the genome.  相似文献   
120.
Chondrocalcinosis is a metabolic disease caused by the presence of calcium pyrophosphate dihydrate crystals in the synovial fluid. The goal of our endeavor was to find out whether short peptides could be used as a dissolving factor for such crystals. In order to identify peptides able to dissolve crystals of calcium pyrophosphate, we screened through a random library of peptides using a phage display. The first screening was designed to select phages able to bind the acidic part of alendronic acid (pyrophosphate analog). The second was a catalytic assay in the presence of crystals. The best-performing peptides were subsequently chemically synthesized and rechecked for catalytic properties. One peptide, named R25, turned out to possess some hydrolytic activity toward crystals. Its catalysis is Mg2+-dependent and also works against soluble species of pyrophosphate.  相似文献   
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