Effects of Precooling Treatments on Postharvest Storability and Neohesperidin Metabolism in Sweet Cherries

In order to clarify the effects of precooling treatments on the postharvest storability and neohesperidin metabolism of sweet cherries, forced-air precooling, ice-water precooling, cold storage precooling and ozone ice-water precooling were used to treat ‘Red Agate’ sweet cherries prior to being stored at (0.0 ± 0.5) ℃. The sensory quality, nutritional quality, respiratory metabolism, disease resistance-related enzyme activities, neohesperidin content and related gene expression in sweet cherries were analyzed during storage. In addition, the key indicators for the evaluation of storability and the key regulatory genes of neohesperidin metabolism in sweet cherries were selected by correlation analysis. The results showed that compared with commercial precooling (cold storage precooling), forced-air precooling significantly increased the activities of peroxisome (POD), superoxide dismutase (SOD), catalase (CAT), cinnamic acid-4-hydroxylase (C4H), cinnamyl-alcohol dehydrogenase (CAD) and 4-coumarate:coenzyme A ligase (4-CL), maintained higher fruit hardness, and reduced the disease index, dry fruit stem incidence, and browning index of sweet cherry during storage (P 0.05). VC content, and the activities of C4H, CAD and 4-CL (key enzymes in the phenylpropane metabolic pathway), SOD, PPO and lipoxygenase showed a significant correlation with the sensory quality of sweet cherries, which could be used as key physiological indicators to evaluate the storage stability of sweet cherry. The content of neohesperidin in sweet cherries fluctuated and decreased during storage. Forced-air precooling could promote neohesperidin synthesis by improving the gene expression of LOC110760277, LOC110751411, LOC110757814, QXJJ01001021, LOC110745765 and LOC110756675 and inhibiting the gene expression of LOC110758277 and LOC110771557. These results indicated that forced-air precooling was more effective in improving the storage storability of sweet cherries and promoting neohesperidin synthesis than ice-water precooling, cold storage precooling and ozone ice-water precooling

Yersinia pestis and Plague: Some Knowns and Unknowns

Since its first identification in 1894 during the third pandemic in Hong Kong, there has been significant progress in understanding the lifestyle of Yersinia pestis , the pathogen that is responsible for plague. Although we now have some understanding of the pathogen’s physiology, genetics, genomics, evolution, gene regulation, pathogenesis and immunity, there are many unknown aspects of the pathogen and its disease development. Here, we focus on some of the knowns and unknowns related to Y. pestis and plague. We notably focus on some key Y. pestis physiologic and virulence traits that are important for its mammal-flea-mammal life cycle, but also its emergence from the enteropathogen, Yersinia pseudotuberculosis . Some aspects of the genetic diversity of Y. pestis , the distribution and ecology of plague, as well as the medical countermeasures to protect our population are also provided. Lastly, we present some biosafety and biosecurity information related to Y. pestis and plague

Characterization of an aspartate aminotransferase encoded by YPO0623 with frequent nonsense mutations in Yersinia pestis

Yersinia pestis, the causative agent of plague, is a genetically monomorphic bacterial pathogen that evolved from Yersinia pseudotuberculosis approximately 7,400 years ago. We observed unusually frequent mutations in Y. pestis YPO0623, mostly resulting in protein translation termination, which implies a strong natural selection. These mutations were found in all phylogenetic lineages of Y. pestis, and there was no apparent pattern in the spatial distribution of the mutant strains. Based on these findings, we aimed to investigate the biological function of YPO0623 and the reasons for its frequent mutation in Y. pestis. Our in vitro and in vivo assays revealed that the deletion of YPO0623 enhanced the growth of Y. pestis in nutrient-rich environments and led to increased tolerance to heat and cold shocks. With RNA-seq analysis, we also discovered that the deletion of YPO0623 resulted in the upregulation of genes associated with the type VI secretion system (T6SS) at 26°C, which probably plays a crucial role in the response of Y. pestis to environment fluctuations. Furthermore, bioinformatic analysis showed that YPO0623 has high homology with a PLP-dependent aspartate aminotransferase in Salmonella enterica, and the enzyme activity assays confirmed its aspartate aminotransferase activity. However, the enzyme activity of YPO0623 was significantly lower than that in other bacteria. These observations provide some insights into the underlying reasons for the high-frequency nonsense mutations in YPO0623, and further investigations are needed to determine the exact mechanism

Isothermal and isovolumetric process of CO2 adsorption on nitrogen-doped biochar: Equilibrium and non-equilibrium states

In order to reveal the thermodynamic properties of CO2 adsorption on a promising nitrogen-doped biochar under isothermal and isovolumetric conditions, the adsorption isotherms based on 391 data points were experimentally obtained to investigate the mass and energy transfer process during CO2 adsorption by combining with model analysis. Then a series of interesting phenomena were found by analyzing those thermodynamic parameters in the equilibrium and non-equilibrium states. The capacity of CO2 on the biochar non-linearly increases with an increase of the initial pressure and volume-mass ratio but the decrease of the adsorption temperature. It can be up to 7.6 mol/kg at 273 K and 100 kPa. The adsorption system exchanges the energy with the surrounding environment mainly by heat transfer. And the interfacial energy of the adsorbent can be affected by the adsorbate system in three parts: pressure change from gas phase, molecular force from adsorbed phase and heat transfer. Then the conditions with low adsorption temperature, high initial pressure and large volume-mass ratio can provide a strong driving force for CO2 adsorption. These phenomena that have not been reported before will help us get a better technical process for CO2 capture

Modelling& Simulation and Protection& Control Verification Method for Asynchronous Motor-Synchronous Generator Sets

Power supply system made of asynchronous motor-synchronous generator sets (M-G sets) is often used as power supply for important loads. The system usually consists of two M-G sets. Unlike synchronous generators connecting to large power grid, the two generators in the system can have significant effect on the other when field loss fault occurs. If the protection settings are inappropriate, the two generators may trip one after another during a fault on a single generator, causing the important load losing all the power supply. This paper proposed a simulation and protection verification method based on the RTDS digital modelling for M- G sets including detailed excitation system. The modelling and simulation methods can effectively verify the reasonability of settings of the P-Q restriction of the excitation regulator and the PID controllers, and provide the important basis for the setting of over-current protection and loss of excitation protection, ensuring the safe operation of the power supply system made of M-G sets

Quantification and coupling of the electromagnetic and chemical contributions in surface-enhanced Raman scattering

In surface-enhanced Raman scattering (SERS), both chemical (CE) and electromagnetic (EM) field effects contribute to its overall enhancement. However, neither the quantification of their relative contributions nor the substrate dependence of the chemical effect have been well established. Moreover, there is to date no understanding of a possible coupling between both effects. Here we demonstrate how systematically engineered silver and gold planar and nanostructured substrates, covering a wide range of field enhancements, provide a way to determine relative contributions of chemical and electromagnetic field-enhancement in SERS measurements of benzenethiol. We find a chemical enhancement of 2 to 14 for different vibrational resonances when referencing against a vibrational mode that undergoes minimal CE. The values are independent of substrate type and independent of the enhancement of the electromagnetic intensity in the range from 1 to 106. This absence of correlation between chemical and electromagnetic enhancement resolves several long-standing controversies on substrate and intensity dependence of the chemical enhancement and allows for a more systematic design of SERS substrates with desired properties

The Reduced Oligomerization of MAVS Mediated by ROS Enhances the Cellular Radioresistance

Although the mitochondrial antiviral signaling protein (MAVS), located in the mitochondrial outmembrane, is believed to be a signaling adaptor with antiviral feature firstly, it has been shown that suppression of MAVS enhanced radioresistance. The mechanisms underlying this radioresistance remain unclear. Our current study demonstrated that knockdown of MAVS alleviated the radiation-induced mitochondrial dysfunction (mitochondrial membrane potential disruption and ATP production), downregulated the expressions of proapoptotic proteins, and reduced the generation of ROS in cells after irradiation. Furthermore, inhibition of mitochondrial ROS by the mitochondria-targeted antioxidant MitoQ reduced amounts of oligomerized MAVS after irradiation compared with the control group and also prevented the incidence of MN and increased the survival fraction of normal A549 cells after irradiation. To our knowledge, it is the first report to indicate that MAVS, an innate immune signaling molecule, is involved in radiation response via its oligomerization mediated by radiation-induced ROS, which may be a potential target for the precise radiotherapy or radioprotection

The diagnostic value of quantitative bone SPECT/CT in solitary undetermined bone lesions

ObjectiveTo investigate the diagnostic value of the maximum standard uptake value (SUVmax) of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) in solitary undetermined bone lesions.MethodsIn Part I, retrospective study, 167 untreated patients with extra-skeletal malignant tumors by pathology were consecutively enrolled for staging with Tc-99m methyl-diphosphonate (99mTc-MDP) whole-body bone scan (WBS) and quantitative SPECT/CT, and a total of 396 bone lesions with abnormal radioactivity concentration in 167 patients were included from April 2019 to September 2020. The differences in SUVmax among the benign bone lesions, malignant bone lesions, and normal vertebrae were analyzed. The receiver operating characteristic (ROC) curve and cutoff value of SUVmax were obtained. Part II, prospective study, 49 solitary undetermined bone lesions in SPECT/CT in 49 untreated patients with extra-skeletal malignant tumors were enrolled from October 2020 to August 2022. The diagnostic efficacy of SUVmax in solitary undetermined bone lesions was assessed. The final diagnosis was based on follow-up imaging (CT, MRI, or 2-deoxy-2-[18F]fluoro-D-glucose-positron emission tomography/computed tomography) for at least 12 months.ResultsIn Part I, a total of 156 malignant and 240 benign bone lesions was determined; the SUVmax of malignant lesions (26.49 ± 12.63) was significantly higher than those of benign lesions (13.92 ± 7.16) and normal vertebrae (6.97 ± 1.52) (P = 0.00). The diagnostic efficiency of the SUVmax of quantitative SPECT/CT revealed a sensitivity of 75.00% and a specificity of 81.70% at a cutoff value of 18.07. In Part II, 17 malignant and 32 benign lesions were determined. Using SUVmax ≥18.07 as a diagnostic criterion of malignancy, it has a sensitivity of 82.35%, a specificity of 93.75%, and an accuracy of 89.80%.ConclusionThe SUVmax of quantitative SPECT/CT is valuable in evaluating solitary undetermined bone lesions. Using a cutoff SUVmax value of 18.07, quantitative SPECT/CT demonstrated high sensitivity, specificity, and accuracy in differentiating malignant from benign bone lesions