A nickel-catalyzed benzylic substitution of secondary phosphine oxide was described, affording the dialkylated P-stereogenic tertiary phosphine oxides with high to excellent enantioselectivities. The ...reaction was performed under mild conditions with commercially available benzyl chlorides and bench stable secondary phosphine oxides, exhibiting broad functional group tolerance. It represented a practical example for the preparation of P-stereogenic phosphine compounds.
The phase-to-ground admittance in distribution networks is asymmetric. This asymmetry is aggravated by the arc suppression coil, resulting in zero-sequence overvoltage. The magnitude of zero-sequence ...overvoltage can exceed the line-to-ground voltage, endangering the operation of electrical equipment. Moreover, after the occurrence of a single-line-to-ground fault, the change law of the three-phase voltage is affected by the zero-sequence overvoltage, leading to misjudgment of the fault phase. Accordingly, this paper proposes a fault phase selection method based on active current injection that can adapt to asymmetric distribution networks. The fault phase is selected by injecting current and calculating the equivalent power supply voltage of the faulty line without increasing the ground-fault current. The high sensitivity of the proposed fault phase selection method was verified for high impedance faults through software simulations and prototype experiments. Moreover, the zero-sequence overvoltage can be suppressed by a single-phase flexible arc suppression device during the normal operation of distribution networks. The ground-fault current can be quickly suppressed at different ground-fault locations and resistance values, ensuring the extinguishment of the ground-fault arc.
BACKGROUND
Sturgeon is popular for its nutritious value and its taste. However, sturgeon fillets are traditionally heated in 100 °C boiling water, resulting in unfavorable taste and with a negative ...effect on the quality. This study considered the effect of combinations of vacuum and low‐temperature treatments (LTVH groups) on sturgeon fillets compared with the traditional heat treatment (TC groups).
RESULTS
The results show that the LTVH groups had lower cooking‐loss rates. All LTVH fillets were changed to a white color, and appeared ‘done’, as did the TC fillets. The LTVH and TC methods gave rise to significant differences in texture: the springiness of the LTVH groups decreased with heating time, and decreased rapidly in the TC groups (P < 0.05); hardness and chewiness increased with time and temperature in the LTVH groups, but decreased in the TC groups. More compact and denser gaps were observed in LTVH70 groups and TC groups. Less protein and lipid oxidation was evident in LTVH groups, including more myofibril protein solubility; there was less protein aggregation, fewer thiobarbituric acid reactive substance, and Schiff base.
CONCLUSION
Vacuum and low‐temperature treated sturgeon fillets can be served as a good alternative. This treatment caused slight tissue damage and less proteolysis and lipid oxidation, which is beneficial for the quality of aquatic products.
Squid ink is rich in abundant natural proteins, lipids, and minerals. The aim of this study was to investigate the influences of different types and contents of modified starch with different ...processes on the stability and fluidity of squid ink sauces. Results of scanning electron microscopy demonstrated that the adsorption quantities of acetylated distarch phosphate (ADSP) were significantly higher than acetylated distarch adipate and hydroxypropyl distarch phosphate. Results of rheological properties and textural characteristics showed that squid ink sauce treated with ADSP had the highest dynamic viscoelasticity and adhesiveness, respectively. Meanwhile, overall quality of squid ink sauce with addition of 150% ADSP showed the highest scores. In addition, squid ink sauce treated with wet process (WP) showed higher stability and smaller particle size than dry process. The effects of processes on the volatile compounds of squid ink sauces were relatively small. In summary, the combination of 150% ADSP and squid ink treated with WP could improve the uniformity and gelling of squid ink sauce.
The aim of this study was to investigate the influences of different types and contents of modified starch with different processes on the stability and fluidity of squid ink sauces. The combination of 150% acetylated distarch phosphate and squid ink treated with wet process could improve the uniformity and gelling of squid ink sauce.
Advanced glycation end products (AGEs) are generated in all stages of food thermal treatment. In order to reveal the inhibitory mechanism of AGEs, a range of concentration of ...(−)-epigallocatechin-3-gallate (EGCG) has been added during low-temperature vacuum heating (LTVH), and high-resolution mass spectrometry-based proteomics was applied for identifying and quantifying N-glycosylated proteins, N-glycosylated peptides, and N-glycosylated sites. The results indicated that, compared with atmospheric cooking, LTVH significantly decreased the generation of AGEs. The addition of EGCG has a positive effect on the inhibition of AGEs when the concentration is lower than 2,000 μg/mL, and 200 μg/mL was the optimal concentration.
•HTS and metabolomic based on LC-MS/GC–MS of sea urchin gonads were performed.•Dominant genus transformed from Ralstonia to Aliivibrio during storage.•GC–MS based metabolites enriched in valine, ...leucine and isoleucine biosynthesis.•LC-MS based metabolites enriched in alanine, aspartate and glutamate metabolism.•Aliivibrio had a great influence on the production of differential metabolites.
Sea urchin gonads have high nutritional value and degenerate rapidly during storage. Previous assessment of the freshness of sea urchin gonads was based on experience without valid biochemical indicators. Thus, the current study is to find biochemical indicators representing the freshness of sea urchin gonads. Results showed that the dominant genera of sea urchin gonads were changed from Psychromonas, Ralstonia, and Roseimarinus to Aliivibrio, Psychrilyobacter, and Photobacterium. The differential metabolites of sea urchin gonads were mainly produced through amino acids metabolism. Among them, GC-TOF-MS based differential metabolites had the greatest enrichment in the valine, leucine and isoleucine biosynthesis pathway, while LC-MS based differential metabolites had the greatest enrichment in the alanine, aspartate and glutamate metabolism pathway. The growth of dominant genus (Aliivibrio) had a great influence on the production of differential metabolites. These results will provide valuable information for accurately judging the freshness and shelf life of sea urchin gonads.
Salting is important to maintain the food quality. This study aimed to evaluate the physicochemical properties and microstructure of Russian sturgeon fillets under vacuum impregnation and find out ...appropriate salting conditions. The treatments varied in salt concentration (5%, 10%, 15%, and 20%) and time (1, 2, 3, 4, and 5 hr); samples treated under atmospheric pressure with 10% were included as controls. In our study, vacuum impregnation improved the salting efficiency and helped to maintain a complete microstructure to enhance the water‐holding capacity, especially after salting for 2 hr, the maximum value was 32.4%. Moreover, it increased the values of hardness and springiness and reduced L* and a*. In addition, the fillets under vacuum impregnation had lower TVB‐N and Carbonyl content, which were 15.91 mg/100 g and 311.38 nmol/L after salting for 5 hr, respectively. Consequently, vacuum impregnation was a better way of salting for its higher salting efficiency and better physicochemical properties.
Practical applications
The results of this study provide information to food industry about the effects of different salt concentration and time under vacuum impregnation on the Russian sturgeon fillets. It can be seen from the results that vacuum impregnation can improve the salting efficiency and protect the original organizational structure as completely as possible. As a result, vacuum impregnation is a better way of salting.
Background: Medical misuse of antibiotics is associated with the acquisition and spread of antibiotic resistance, resulting in a lack of effective drugs and increased health-care cost. Nevertheless, ...inappropriate antibiotic use in China remains common and the situation requires urgent improvement. Here, we analyzed the prescriptions of antibiotics and evaluated the rationality of antibiotic use among outpatients in Beijing general hospitals during 2015.
Methods: We collected basic medical insurance claim data from January 1, 2015 to December 31, 2015 in 507 general hospitals of Beijing. A descriptive analysis of outpatient antibiotic prescribing was performed. The Anatomical Therapeutic Chemical Classification/defined daily doses system was used to evaluate the rationality of antibiotic use.
Results: Over the study, an estimated 721,930, 613,520, and 822,480 antibiotics were dispensed in primary, secondary, and tertiary general hospitals corresponding to 5.09%, 5.06%, and 2.53% of all prescriptions, respectively. Antibiotic combinations represented 2.95%, 7.74%, and 10.18% of the total antibiotic prescriptions, respectively. Expenditure for the top twenty antibiotics in primary, secondary, and tertiary general hospitals was RMB 42.92, 65.89, and 83.26 million Yuan, respectively. Cephalosporins were the most frequently prescribed class of antibiotic in clinical practice. The antibiotics used inappropriately included azithromycin enteric-coated capsules, compound cefaclor tablets and nifuratel nysfungin vaginal soft capsules in primary hospitals, amoxicillin and clavulanate potassium dispersible tablets (7:1) and cefonicid sodium for injection in secondary hospitals, cefminox sodium for injection and amoxicillin sodium and sulbactam sodium for injection in tertiary hospitals.
Conclusions: Antibiotic use in Beijing general hospitals is generally low; however, inappropriate antibiotic use still exists. Inappropriately used antibiotics should be subject to rigorous control and management, and public policy initiatives are required to promote the judicious use of antibiotics.
•Four tomato varieties were obtained by breeding based on different phenotypes.•Taste differences including sourness and bitterness were identified by E-tongue.•Amino acids and organic acids were ...quantified and correlated with taste.•Metabolites related to taste differences were screened and discussed.
Breeding of tomato varieties based on phenotypic traits can potentially lead to a decline in taste and nutritional values, thereby impacting consumer acceptance. However, taste is an intrinsic characteristic of tomatoes. Its decoding requires the identification of crucial compounds and the associated metabolic pathways implicated in taste development and formation. In this study, the taste parameter differences of four tomato varieties were distinguished using an electronic tongue. The content of organic acids and free amino acids, which were closely associated with taste variations, was quantitatively analyzed. Several important taste metabolites and metabolic pathways were identified based on LC-MS metabolomics and enrichment analysis. Through correlation analysis, it was determined that there existed significant associations between the taste, compounds, and metabolites of tomato varieties with different phenotypes. This study could provide references and theoretical basis for tomato breeding, as well as the control and evaluation of taste and quality of tomato varieties.
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