Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

Formation of volatiles in response to tea green leafhopper (Empoasca onukii Matsuda) herbivory in tea plants: a multi-omics study

Combined transcriptome and metabolome analysis of fresh leaf infestation by tea green leafhoppers (Empoasca (Matsumurasca) onukii Matsuda) suggests roles for alternative pre-mRNA splicing and mRNAs in the regulation of aroma formation in tea plants. Oriental Beauty is a high-grade, oolong tea with a pronounced honey-like aroma and rich ripe fruit flavor that develops primarily as a result of the infestation of the fresh leaves by tea green leafhoppers (Empoasca (Matsumurasca) onukii Matsuda). Here, we used PacBio Iso-Seq and RNA-seq analyses to determine the full-length transcripts and gene expression profiles of fresh tea leaves in response to E. (M.) onukii herbivory. We investigated the relationship between RNA-seq, tea metabolites, and aroma response mechanisms in leaves infested by leafhoppers. We found 3644 differentially expressed genes, of which 2552 were up- and 1092 were down-regulated. A total of 49,913 alternative splicing events were predicted, including 324 differential AS events. Moreover, 3105 differentially expressed transcripts were also identified, of which 2295 were up- and 810 were down-regulated. The characterization of expression patterns of the key gene transcript isoforms involved in the aroma formation pathways identified 130 differentially expressed metabolites, 97 of which were up- and 33 were down-regulated. Two key aroma compounds (phenylacetaldehyde and 4-hydroxybenzaldehyde) were highly correlated with genes of the aroma formation pathways. Our results revealed that pre-mRNA AS plays a crucial role in the metabolic regulation surrounding aroma formation under leafhopper herbivory in tea plants.

Comparison of free and bound phenolic compositions and antioxidant activities of leaves from different mulberry varieties

Mulberry leaves are used in traditional Chinese medicine and contain numerous active substances that are known to be beneficial for human health. The aim of this study was to investigate the phenolic compositions and antioxidant activities of the leaves from 23 mulberry cultivars. Qualitative LC-ESI-QTOF analysis revealed the presence of 11 phenolic compounds in the free phenolic extracts and 10 phenolic compounds in the bound fractions. Chlorogenic acid and caffeic acid were the major components in the free and bound fractions, respectively. The results revealed that the changguosang cultivar from Taiwan contained the greatest content of phenolic compounds as well as the highest antioxidant activity among the 23 cultivars examined, as determined using three separate antioxidant assays. The isoquercitrin, chlorogenic acid, and rutin contents of the free phenolic extracts displayed significant correlations with the antioxidant activities, while syringic acid and rutin were the main contributors to the antioxidant activities of the bound phenolic fractions. The obtained results demonstrate that mulberry leaves contain a variety of beneficial phenolic substances and may be suitable for further development as a herbal medicine.

[Correlation between serum CCL20 level and disease severity in patients with rheumatoid arthritis]

Objective: To investigate the correlation between serum CCL20 level and disease severity in patients with rheumatoid arthritis (RA). Methods: From July 2018 to July 2019, a cross-sectional study was conducted in the Department of Rheumatology and Immunology, the Third Affiliated Hospital of Southern Medical University. The observation group consisted of 105 outpatients and inpatients diagnosed with RA, while the control group was 90 healthy people with age and gender matched physical examination in the Third Affiliated Hospital of Southern Medical University. According to Steinbroker classification, RA patients were divided into Steinbroker grade 2 group (n=35), Steinbroker grade 3 group (n=38) and steinbroker grade 4 group (n=32); according to DAS28 score, RA patients were divided into remission group (DAS28<2.6)(n=39), mild active group (DAS28 2.6-3.2)(n=25), moderate active stage group (DAS28 3.2-5.1)(n=20) and severe active stage group (DAS28 ≥ 5.1)(n=21). The levels of chemokine ligand 20 (CCL20), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were detected by ELISA. The levels of CCL20 in each group were compared, and the correlation between CCL20 and other indicators was analyzed. The receiver operating characteristic (ROC) curve of CCL20 in diagnosis of RA was analyzed to explore the correlation between CCL20 and disease severity of RA patients. Results: Compared with the normal control group, the serum CCL20 level in RA patients was significantly increased [(48.1±16.7) pg/ml vs (17.6±5.9) pg/ml, t=19.39, P<0.001]. In addition, serum CCL20 in steinbroker grade 4 group was significantly higher than that in Steinbroker grade 3 group [(59.5±10.1) pg/ml vs (47.4±17.5) pg/ml, t=3.472, P<0.001], and the serum CCL20 level in steinbroker grade 3 group was significantly higher than that in steinbroker grade 2 group [(47.4±17.5) pg/ml vs (38.4±14.6) pg/ml, t=2.370, P<0.001], CCL20 level in steinbroker grade 2 group was significantly higher than that in normal control group [(38.4±14.6) pg/ml vs (17.6±5.9) pg/ml, t=7.738, P<0.001]. In addition, serum CCL20 level was significantly positively correlated with steinbroker score (r=0.505, P<0.001); CCL20 level in active RA patients was significantly higher than that in remission RA patients [(57.2±13.2) pg/ml vs (32.7±8.9) pg/ml, t=10.31, P<0.001]. The serum CCL20 level in severe activity group was significantly higher than that in moderate activity group [(60.6±10.9) pg/ml vs (51.7±16.2) pg/ml, t=0.212, P=0.040], and the serum CCL20 level in moderate activity group was significantly higher than that in mild activity group [(51.7±16.2) pg/ml vs (40.5±18.6) pg/ml, t=0.217, P=0.037]. In addition, there was a significant positive correlation between serum CCL20 level and DAS28 score (r=0.451, P<0.001). In addition, serum CCL20 level was positively correlated with serum CRP (r=0.332, P<0.001). According to the ROC curve, the specificity of steinbroker grade 2 group was 0.53, and the sensitivity was 0.74, AUC was 0.659; the sensitivity of steinbroker grade 3 group was 0.78, and the specificity was 0.69, AUC was 0.734; the sensitivity of mild vs medium stage was 0.64, and the specificity was 0.70, AUC was 0.699; the sensitivity of medium stage vs severe stage was 0.57, and the specificity was 0.68,AUC was 0.678. Conclusion: Serum CCL20 level in RA patients is significantly increased and positively correlated with disease severity, which may be used as a marker to observe and evaluate the progression of RA.

Lemon essential oil/vermiculite encapsulated in electrospun konjac glucomannan-grafted-poly (acrylic acid)/polyvinyl alcohol bacteriostatic pad: Sustained control release and its application in food preservation

Lemon essential oils (LEO), as natural bacteriostatic agents, show significant loss in the preparation processes of food packaging materials, therefore, an effective encapsulation of LEO is urgent for realizing the protection. In this study, LEO was absorbed by thermally stable and porous vermiculite (VML) to form LEO/VML complex, which is further coupled with konjac glucomannan-grafted-poly (acrylic acid)/polyvinyl alcohol (KGM-g-PAA/PVA) composite. KGM-g-PAA/PVA bacteriostatic water-absorbing pad was prepared via electrospinning technique, which can minimize the loss of LEO. The VML (1 g) can significantly reduce LEO loss and achieve sustained control LEO release from the pad, which follows the predominant mechanism of Fick diffusion law. The sustained control LEO release from the pad can effectively inhibit the growth of E. coli during storage, thus prolonging shelf life of chilled pork for 3 day. This study suggests that KGM-g-PAA/PVA pad may have a great potential in the field of intelligent packaging.

High Hydrostatic Pressure and Co-Fermentation by Lactobacillus rhamnosus and Gluconacetobacter xylinus Improve Flavor of Yacon-Litchi-Longan Juice

The aim of this study was to evaluate the effect of high hydrostatic pressure (HHP) and co-fermentation by Lactobacillus rhamnosus and Gluconacetobacter xylinus on the quality of yacon-litchi-longan (YLL) juice. The carbohydrates, organic acids, free amino acids (FAAs), and volatile compounds in YLL juice were analyzed. Thermal processing (TP) increased the content of total carbohydrates, organic acids and FAAs, and destroyed the aroma components, whereas HHP treatment had a negligible effect. Carbohydrate content was lower, and content of lactic acid, acetic acid, and exopolysaccharide (EPS) were higher in co-fermented juice than in unfermented juice. Furthermore, the content of bitter FAAs in fermented TP and HHP-treated YLL juices decreased by 88.7% and 86.9%, respectively. Co-fermentation also increased ketones and the sum of individual volatile constituents, and improved the overall flavor of juice. Taken together, HHP treatment prior to co-fermentation can be used to improve the quality of YLL juice, especially the flavor thereof.

Comparison of pulsed vacuum and ultrasound osmotic dehydration on drying of Chinese ginger (Zingiber officinale Roscoe): Drying characteristics, antioxidant capacity, and volatile profiles

The effects of pulsed vacuum osmotic dehydration (PVOD) and ultrasound osmotic dehydration (USOD) on drying characteristics and quality attributes of ginger were investigated. PVOD was subjected to pulsed vacuum at 13 kPa for 30 min, and USOD was subjected to ultrasound with the frequency of 40 kHz for 30 min. After PVOD and USOD treatments, the samples were then dried at intermittent microwave & air-drying oven with an output of 700 W and temperature of 60°C to the final moisture content of 0.12 g water/g d.w. The results showed PVOD and USOD treatments could improve the total phenolic contents by -1.8% to 16.4%, total flavonoid content by 7.7%-18.7%, DPPH radical scavenging by 9.5%-12.2%, and ABTS+ antioxidant activity by 17.8%-27.4%, although they prolonged the later stages drying of ginger. Besides, the PVOD- and USOD-pretreated dried samples had less brownings than the untreated-dried samples which could be attributed to the inactivation of polyphenol oxidase (PPO) and peroxidase (POD). The PPO activity was significantly reduced in the PVOD and USOD ginger, whereas POD activity was decreased in USOD ginger but increased in PVOD ginger. Moreover, PVOD pretreatment also led to a better preservation of volatile profiles and cell structure than USOD treatment. Therefore, both PVOD and USOD are effective pretreatments for drying of ginger.

Natamycin treatment reduces the quality changes of postharvest mulberry fruit during storage

This study investigated the effect of natamycin (NA) treatment on the quality of mulberry fruit throughout the storage at 8°C and 90% relative humidity. The results of this study showed that NA treatment reduced the decay rate of mulberry fruit, inhibited respiration, decreased malondialdehyde (MDA) content, decreased phenylalanine ammonia-lyase (PAL) and polyphenoloxidase (PPO) activity, and maintained sucrose levels, total soluble solids (TSS), and total acids (TA) contents in the fruits throughout storage. NA treatment maintained the surface color and firmness of fruits throughout storage and suppressed the production of fructose, glucose, total phenolics, and the contents of anthocyanin. NA treatment maintained the quality of mulberry fruit throughout storage by enhancing the enzymatic activity of the reactive oxygen species (ROS) scavengers: catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) and inhibiting the production of hydrogen peroxide (H₂ O₂ ). Treatment of mulberries with increasing concentrations of NA could significantly inhibit the growth of fungal pathogens in mulberry fruits and improve their quality. PRACTICAL APPLICATIONS: The results from our previous study showed that NA was a safe preservative which could effectively inhibit the growth of molds and yeasts in mulberry fruits and improve their quality throughout the postharvest storage. Compared with other treatments for mulberry fruit, NA treatment has the advantages of low cost, simple operation, good application, and extension. The results in this study further prove that application of NA treatment has potential in the food industry to maintain the postharvest quality and extend the shelf life of mulberry fruits throughout storage.

Effect of ethyl oleate pretreatment on blueberry (Vaccinium corymbosum L.): drying kinetics, antioxidant activity, and structure of wax layer

Blueberry belongs to the genus vaccinium, which is rich in a variety of biologically active components beneficial to the human body. Drying of blueberry is a slow and energy-intensive process because of its waxy skin, which has low permeability to moisture. Therefore, chemical pretreatment of ethyl oleate (AEEO) was adopted to accelerate moisture diffusivity. The results showed that the drying rate of blueberries was increased significantly by AEEO treatment, and the drying time can be shortened by 17.17-40.70%. After AEEO dipping, the effective diffusion coefficient increased from 5.461 × 10^-9 to 1.067 × 10^-8 m²/s at 60 °C. Six semi-theoretical thin-layer models were used to estimate the curves of air-drying of blueberry, and Wang-Singh model was found to perform better than other models. Besides, the rehydration and retention of nutritional contents were also improved by AEEO dipping. The total phenolics, total flavonoids, total anthocyanin content, and ABTS*+ scavenging activity of blueberry were increased by 37.74%, 21.01%, 47.83%, and 30.75%, respectively. The result of SEM observation and cell-membrane permeability indicated that AEEO could break down the wax layer of blueberry, change the crystal structure of wax layer, and increase cell permeability, which resulted in shorter drying time and higher quality of blueberry.

Protein and polyphenols involved in sediment formation in cloudy litchi juice

Sedimentation is a major issue in juice production. This paper aims to study the mechanisms of precipitate formation during the storage of cloudy litchi juice. The sediment concentration, relative turbidity, and ζ potential were analyzed. The supernatant and sediment were separated to determine the contents of proteins and phenolics. The results showed that the amount of sediment increased during the storage. In addition, the total protein and total phenolic content in the supernatant decreased, whereas the glutelin and total phenolic contents in the sediment increased significantly (p < 0.05). Moreover, our results showed that the amounts of procyanidin B₂ and quercetin-3-O-rutinose-7-O-rhamnoside in the supernatant decreased noticeably. However, these two substances could not be detected in the sediment. In summary, the formation of sediment from litchi juice is mainly caused by the slow denaturation of proteins and the oxidation of procyanidin B₂ and quercetin-3-O-rutinose-7-O-rhamnoside.

[Risk factors for low anterior resection syndrome]

Objective: While low anterior resection avoided a permanent stoma, it might also cause bowel dysfunction which can significantly impact patients' quality of life. The objective of this study was to identify the incidence and risk factors for the development of bowel dysfunction following rectal surgery. Methods: Patients undergoing anterior resection for rectal neoplasm between January 2010 and December 2015 were identified from a rectal cancer database at the Department of Gastrointestinal Surgery, Beijing Hospital. All patients were asked to fill in a low anterior resection syndrome (LARS) questionnaire. Clinical factors were compared between patients with major LARS and those with minor or no LARS using conditional logistic regression. Results: There was 254 patients enrolled in the study. One hundred and eleven (44.1%) had major LARS symptoms. Neoadjuvant radiotherapy (OR=2.814, 95%CI: 1.097-5.561, P<0.001), low tumor location (OR=3.568, 95%CI: 1.159-6.546, P<0.001) and anastomotic leakage (OR=6.574, 95%CI: 1.689-15.367, P<0.001) were independent risk factors for development of major LARS symptoms. Conclusions: For patients with high risk of low anterior resection syndrome, the potential for long-term poor functional results should be discussed with patients and form a part of the decision-making in individual treatment plans. Sphincter-preserving surgery should be performed in highly selected patients to avoid major bowel dysfunction.