Effects of Dry Aging Times on the Quality of Yak Meat

To investigate the changes in the quality of yak meat at different dry aging times (7, 14, 21, 28 and 35 d), in this study, sensory evaluation, texture analysis, and GC-IMS were employed to investigate the changes in texture and flavor of yak meat during different dry aging periods. Additionally, PLS-DA was utilized to identify the characteristic flavor compounds. The results showed that the dry aged 35 days sample exhibited the highest comprehensive score, with intact soft tissue structure and a favorable overall acceptability of aroma. The dry aging time had significant effects on the hardness, chewability, and adhesivity of yak meat (P<0.05), which displayed a decreasing trend as aging time extended. A total of 50 volatile compounds were detected, including 14 alcohols, 11 aldehydes, 12 esters, 3 olefins, and 2 acids (mono and dipolymers). The relative contents of aldehydes, alcohols, and esters increased with ripening time while the relative contents of ketones and olefins decreased. There were significant differences in the overall flavor of yak meat at various maturation stages, with greater disparities observed between 0 days and 35 days. 17 key volatile compounds were identified, including 3-Hydroxy-2-butanone(D), 1-hexanol (M), and hexanal (D). This study revealed the effects of dry aging time on the texture and flavor of yak meat, providing a theoretical basis for the flavor formation and product development of dry-aged yak meat

Characterization of flavor profile of Steamed beef with rice flour using gas chromatography-ion mobility spectrometry combined with intelligent sensory (Electronic nose and tongue)

The intelligent senses (Electronic nose and tongue), were combined with headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) and free amino acid were used in combination to determine the aroma and taste components during the processing of Chinese traditional dish Steamed beef with rice flour (SBD). The findings revealed that E-nose and E-tongue, could clearly distinguish and identify the aroma and taste of SBD. A total of 66 volatile substances and 19 free amino acids were identified by HS-GC-IMS and amino acid analyzer, respectively. The highest contribution to aroma in the production of SBD was alcohols, esters and aldehydes. Further analysis of relative odor activity showed that 3-Methylbutanol-D, 3-Methylbutanol-M and 3-Methylthio propanal is the marinating stage (T2) main aroma components. Ethyl 3-methylbutanoate-M and Ethyl 3-methylbutanoate-D were the main aroma components in the seasoning stage (T3). Additionally, the calculation of the taste activity value showed that Glutamic contributed significantly to the umami of SBD. Alanine was a representative taste component in the marinating stage (T2), while Proline, Aspartic, Lysine, Glutamic, Valine, Arginine, and Histidine were characteristic amino acids of the seasoning stage (T3). Consequently, this study offers valuable insights into the industrial-scale production and flavor regulation of SBD products

The Loss-Averse Newsvendor Problem with Random Yield and Reference Dependence

This paper studies a loss-averse newsvendor problem with reference dependence, where both demand and yield rate are stochastic. We obtain the loss-averse newsvendor&rsquo;s optimal ordering policy and analyze the effects of loss aversion, reference dependence, random demand and yield on it. It is shown that the loss-averse newsvendor&rsquo;s optimal order quantity and expected utility decreases in loss aversion level and reference point. Then, that this order quantity may be larger than the risk-neutral one&rsquo;s if the reference point is less than a negative threshold. In addition, although the effect of random yield leads to an increase in the order quantity, the loss-averse newsvendor may order more than, equal to or less than the classical one, which significantly depends on loss aversion level and reference point. Numerical experiments were conducted to demonstrate our theoretical results

A Vehicle Steering Recognition System Based on Low-Cost Smartphone Sensors

Recognizing how a vehicle is steered and then alerting drivers in real time is of utmost importance to the vehicle and driver’s safety, since fatal accidents are often caused by dangerous vehicle maneuvers, such as rapid turns, fast lane-changes, etc. Existing solutions using video or in-vehicle sensors have been employed to identify dangerous vehicle maneuvers, but these methods are subject to the effects of the environmental elements or the hardware is very costly. In the mobile computing era, smartphones have become key tools to develop innovative mobile context-aware systems. In this paper, we present a recognition system for dangerous vehicle steering based on the low-cost sensors found in a smartphone: i.e., the gyroscope and the accelerometer. To identify vehicle steering maneuvers, we focus on the vehicle’s angular velocity, which is characterized by gyroscope data from a smartphone mounted in the vehicle. Three steering maneuvers including turns, lane-changes and U-turns are defined, and a vehicle angular velocity matching algorithm based on Fast Dynamic Time Warping (FastDTW) is adopted to recognize the vehicle steering. The results of extensive experiments show that the average accuracy rate of the presented recognition reaches 95%, which implies that the proposed smartphone-based method is suitable for recognizing dangerous vehicle steering maneuvers

Development of the fundamental power coupler for 324 MHz superconducting cavities

The China Spallation Neutron Source upgrade project (CSNS-II) has completed the preliminary design report and is expected to start in the fall of 2023. It plans to add two types of superconducting cavities: the 324-MHz double spoke superconducting cavity and the 648-MHz elliptical superconducting cavity in the linac section of the accelerator to upgrade the beam power from 100 to 500 kW, requiring more than 40 new fundamental power couplers (FPCs). These couplers will operate at pulse mode with a peak power ranging from 100 to 380 kW. To master the entire R&D process of the FPC for superconducting cavities, meanwhile, provide the horizontal test condition for various superconducting cavities research, a pair of 324-MHz power couplers for the double spoke superconducting cavity are developed. This coupler is a coaxial structure with a disk-warm ceramic window, and its characteristic impedance is 50  Ω. Multiphysics design is performed to ensure that the coupler meets the actual requirements. Structures of the coupler are optimized to realize a clean assembly with the cavity in Class 10 clean room and avoid window failure due to the bombardment of electrons generated by possible cavity field emission. We have successfully fabricated two FPCs and high power conditioned them on the test bench at room temperature. The test results show that FPCs can transmit a peak radio frequency (rf) power of 2 MW with a duty factor of 1.625% in traveling wave mode and an rf power of 500 kW with a duty factor of 3% in standing wave mode with arbitrary reflection wave phase. It meets the requirement of spoke cavities for CSNS-II—200 kW maximum power with a duty factor of 3%. Multipacting (MP) zones found during the high-power conditioning agree reasonably well with those predicted by simulations

Oxidative Stress Responses and Gene Transcription of Mice under Chronic-Exposure to 2,6-Dichlorobenzoquinone

2,6-Dichlorobenzoquinone (2,6-DCBQ), as an emerging disinfection by-production, was frequently detected and identified in the drinking water; however, limited information is available for the toxic effect of 2,6-DCBQ on mice. In the present study, adult mice were used to assess the impact of 2,6-DCBQ via measuring the responses of antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)), the key genes (Heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase 1 (NQO1) and glutamate-L-cysteine ligase catalytic subunit (GCLC)) in the Nrf2-keap1 pathway, and lipid peroxidation (malonaldehyde, MDA). Our results clearly indicated that 2,6-DCBQ decreased the activities of SOD and CAT, repressed the transcriptional levels of key genes in Nrf2-keap1 pathway, further caused oxidative damage on mice. These results provided evidence for assessing the threat of 2,6-DCBQ on human

Pilot Study of Pollution Characteristics and Ecological Risk of Disinfection Byproducts in Natural Waters in Hong Kong

Increased disinfection efforts in various parts of China, including Hong Kong, to prevent the spread of the novel coronavirus may lead to elevated concentrations of disinfectants in domestic sewage and surface runoff in Hong Kong, generating large quantities of toxic disinfection byproducts. Our study investigated the presence and distribution of four trihalomethanes (THMs), six haloacetic acids (HAAs), and eight nitrosamines (NAMs) in rivers and seawater in Hong Kong. The concentrations of THMs (mean concentration: 1.6 µg/L [seawater], 3.0 µg/L [river water]), HAAs (mean concentration: 1.4 µg/L [seawater], 1.9 µg/L [river water]), and NAMs (mean concentration: 4.4 ng/L [seawater], 5.6 ng/L [river water]) did not significantly differ between river water and seawater. The total disinfection byproduct content in river water in Hong Kong was similar to that in Wuhan and Beijing (People's Republic of China), and the total THM concentration in seawater was significantly higher than that before the COVID-19 pandemic. Among the regulated disinfection byproducts, none of the surface water samples exceeded the maximum index values for THM4 (80 μg/L), HAA5 (60 μg/L), and nitrosodimethylamine (100 ng/L) in drinking water. Among the disinfection byproducts detected, bromoform in rivers and seawater poses the highest risk to aquatic organisms, which warrants attention and mitigation efforts. Environ Toxicol Chem 2022;41:2613-2621. © 2022 SETAC.The present study was financially supported by the General Research Fund of Hong Kong (grant. 18300919), FLASS Dean's Research Fund (grant 04615), and Internal Research Fund (grant R4175) of The Education University of Hong Kong.Peer reviewe