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Ghee is a traditional Tibetan dairy product with high-fat content, low yield, plasticity, caseation, and rich nutrition. In this study, we analyzed the diversity of microbial communities in yak milk and ghee samples at high and low altitudes, especially the Lactobacillus genus, and further used metabolomic techniques to compare the differences in metabolites in yak ghee at different altitudes. The results showed that the increase in altitude had a significant and generally inhibitory effect on the microbial community diversity in milk ghee, and yak milk at high altitude was abundant in nutrients, which could antagonize the negative impact of increased altitude. Using non-targeted metabolomics, we infer the composition of flavor compounds in ghee: nine kinds of carboxylic acids, 11 kinds of esters, six kinds of ketones, two kinds of alcohols, and four kinds of alkene compounds, among which the key flavor compounds are dl-2-(acetylamino)-3-phenylephrine acid, 1-(4-methoxyphenyl)-2-propanone, sebacic acid, Lysope 18:1, and uracil 1-beta-d-arabinofuranoside. These flavor substances are found in Lactococcus, Lactobacillus, and Streptococcus. With the participation of Lactobacillus, it is synthesized through biosynthesis of alkaloids derived from ornithine, lysine, and nicotine acid and glyoxylate and decarboxylate metabolism, among which Lactococcus plays a key role. In this study, a variety of lactic acid bacteria related to ghee fermentation were screened out, revealing the composition of volatile flavor compounds in Gannan yak milk ghee in the Qinghai–Tibet Plateau and providing a reference for further key volatile flavor compounds and the formation mechanism of flavor compounds.

When a high-energy laser acts on a film surface, plasma flashes of both the air and film can be generated simultaneously. However, when the conventional plasma flash method is used to identify thin film damage, there is a misjudgment problem caused by the inability to distinguish the air and film plasma flashes. In order to solve the problem of misjudgment, the ignition times of air and thin film plasma flashes can be obtained, respectively. If the ignition times of air and thin film plasma flashes are not equal, they can be distinguished from the time difference. In this paper, a nanosecond Nd:YAG pulse laser is used to break down the air at room temperature and pressure, and the theoretical and experimental values of the ignition time of air plasma flash are obtained. The curves of the ignition time of air plasma flash with the laser wavelength, incident energy, focusing spot, and pulse width are simulated. The reasons for the changes are analyzed from the perspectives of multiphoton absorption, cascade ionization theory, and electromagnetic theory of laser breakdown gas. The results show that when the laser pulse width is 10 ns, the energy is 160 mJ, and the spot radius is 0.015 cm. The theoretical and experimental values of the ignition time of air plasma flash are 2.146 and 2 ns, respectively, which are in good agreement. Larger values of laser focus spot size and pulse width relate to a longer ignition time of the air plasma flash, whereas larger values of laser wavelength and incident energy are related to a shorter ignition time. The research reflects the characteristics and electronic transition of air plasma, as well as the micromorphological evolution of the interaction between laser and air, presents the process of air plasma flash generation and growth, and reveals the ignition mechanism of air plasma. It not only provides a basis for improving the traditional plasma flash identification method to identify film damage but also has a certain scientific significance for studying the generation mechanism of laser-supported combustion waves and detonation waves.

We investigated the damage morphology of porous silicon oxide film with a periodic hexagonal hole array irradiated by nanosecond pulsed laser, both experimentally and numerically. To understand the damage morphology, the temperature field distribution and the thermal stress distribution during the laser radiation process were investigated by finite element method. The simulation results show that the thermal stress regulated by periodic structural surface is the reason for the circumferential and discrete distribution of the damage points. The results provide ideas for improving the laser damage resistance of the structural surfaces.

In a high-power laser system, when the surface pressure of the optical film caused by laser plasma shock wave is greater than the adhesion per unit area of the film layer, the film will produce mechanical damage, and in serious cases, the whole system may not work. Therefore, studying the formation mechanism of optical film surface pressure and impulse caused by laser plasma shock wave is the key to ensure the normal operation of the high-power laser system. In this article, by studying the relaxation process of laser plasma shock wave on the surface pressure of optical film, and using the time accumulation effect of various pressures on the surface of the optical film, the calculation model of impulse on the optical film’s surface formed by laser plasma shock waves was established, and the variation rules of the impulse I st {I}_{\text{st}} and impulse coefficient j j on the unit area of single-layer Al2O3 and HfO2 optical films with different parameters were obtained. When the incident laser wavelength λ \lambda was 1,064 nm, the energy E E was 0.1 J 0.1\hspace{.1em}\text{J} , the pulse width t p {t}_{\text{p}} was 10 ns 10\hspace{.25em}\text{ns} , the focal length of the focusing lens f f was 350 mm 350\hspace{.25em}\text{mm} , the distance between the film surface and the focal plane of the focusing lens z 0 {z}_{0} was 5 mm 5\hspace{.5em}\text{mm} , and the film radius R R was 5 mm 5\hspace{.5em}\text{mm} , the calculation and simulation results show that the impulse I st {I}_{\text{st}} of the two films was 1 0 − 4 N s 1{0}^{-4}\hspace{.5em}\text{N}\hspace{.5em}\text{s} order of magnitude, the impulse coefficient j of the two films was 1 0 − 5 N s/J 1{0}^{-5}\hspace{.5em}\text{N}\hspace{.5em}\text{s/J} , the Al2O3 film with small atomic number will obtain larger I st {I}_{\text{st}} and j j , I st {I}_{\text{st}} and j j of the two films increase with the increase of E E and f f , and I st {I}_{\text{st}} and j j of the two films decrease with the increase of z 0 {z}_{0} and t p {t}_{\text{p}} . In the total impulse transfer time ( t 0 {t}_{0} ), I st {I}_{\text{st}} and j j both increase with the increase of R R .

With the increasing exploitation of lasers, single-band laser protection has been extensively studied. However, single-band laser protection techniques have remained expensive and failed to meet protection requirements for multi-band lasers. In addition, the actual use of protective films requires a specific transmittance, which is generally not met by regular films. Here, we deposited three non-regularized highly reflective films using SiO2 as the low-refractive-index material and TiO2, HfO2, and Ta2O5 as the high-refractive-index materials by thermal evaporation for achieving multi-band laser protection. To verify the effectiveness of the films, the variation in transmittance, damage threshold, standing-wave electric field, and damage morphology of the films were analyzed at two laser wavelengths, and their protection mechanisms were evaluated based on optical properties and damage resistance. The results showed that the reflectances of the prepared non-regularized films at 1064 nm and 532 nm were greater than 99%, and the laser-induced damage thresholds for TiO2/SiO2, HfO2/SiO2, and Ta2O5/SiO2 films were 5.99, 5.89, and 9.99 J/cm2 at 1064 nm and 3.04 J/cm2, 1.48 J/cm2, and 4.93 J/cm2 at 532 nm, respectively, demonstrating good laser protection. The present work provides a practical and effective solution for multi-band laser protection and the prepared films may be used in numerous laser applications.

Background & Aims Cancer-associated fibroblasts (CAFs) play a key role in the cancer process, but the research progress is hampered by the paucity of preclinical models that are essential for mechanistic dissection of cancer cell–CAF interactions. Here, we aimed to establish 3-dimensional (3D) organotypic co-cultures of primary liver tumor–derived organoids with CAFs, and to understand their interactions and the response to treatment. Methods Liver tumor organoids and CAFs were cultured from murine and human primary liver tumors. 3D co-culture models of tumor organoids with CAFs and Transwell culture systems were established in vitro. A xenograft model was used to investigate the cell–cell interactions in vivo. Gene expression analysis of CAF markers in our hepatocellular carcinoma cohort and an online liver cancer database indicated the clinical relevance of CAFs. Results To functionally investigate the interactions of liver cancer cells with CAFs, we successfully established murine and human 3D co-culture models of liver tumor organoids with CAFs. CAFs promoted tumor organoid growth in co-culture with direct cell–cell contact and in a Transwell system via paracrine signaling. Vice versa, cancer cells secrete paracrine factors regulating CAF physiology. Co-transplantation of CAFs with liver tumor organoids of mouse or human origin promoted tumor growth in xenograft models. Moreover, tumor organoids conferred resistance to clinically used anticancer drugs including sorafenib, regorafenib, and 5-fluorouracil in the presence of CAFs, or the conditioned medium of CAFs. Conclusions We successfully established murine and human 3D co-culture models and have shown robust effects of CAFs in liver cancer nurturing and treatment resistance., Graphical abstract

To improve the anti-laser damage performance of one-dimensional (1D) subwavelength gratings (SWGs), this paper proposes to reasonably reduce the peak electric field at the grating ridges to further reduce the laser damage caused by the electric field contribution. Based on Maxwell’s equations, the equations for solving the field intensity of the near-field distribution of the dielectric materials are derived. The numerical simulation theoretical model is described. A 1064 nm laser in the –y direction irradiates the geometric surfaces under two perpendicular polarization directions: perpendicular to the grating ridges (transverse magnetic wave (TM) or x-polarization) and parallel to the grating ridges (transverse electric wave (TE) or z-polarization). We discuss the effects of the profile shape, structural parameters and refractive index of the material on the near-field distribution at the 1D SWG ridges by using a finite element method (FEM). The near-field distribution is sensitive to the x- and z-polarization of incident light. The near-field distribution of the 1D SWGs for TM waves is modulated by the surface, whereas that for TE waves is similar to the distribution of the bare substrate. The results show that the near-field distribution of 1D SWGs greatly depends on the laser polarization direction.

A wide-spectrum high-transmittance copper mesh was designed and fabricated for effective shielding of electromagnetic waves. Using mask lithography and chemical etching, the copper mesh can be easily fabricated. The thickness of the copper mesh is uniform, whether at the crossing section and the copper wire. The average transmittance of the copper mesh from ultraviolet band to near-infrared band (200–2500 nm) is 96%, in agreement with the designed results. The electromagnetic interference shielding efficiency (EMI SE) is to 16 dB in Ku-band. The result of X-ray photoelectron spectroscopy analysis shows that a large amount of Cu2+ on the surface is reduced to Cu0 and Cu+ after annealing. As result, the EMI SE value of copper mesh has increased by 1.5 dB in Ku-band. We envision that the copper mesh can provide a good solution for optically transparent electromagnetic interference shielding.

We designed and fabricated a porous nanostructured film with a hexagonal period for a high-power laser system. The proposed nanostructure exhibits polarization-independent, infrared, and antireflective properties. The measured transmittance of the structural film does not drop below 93% between 948 nm and 2500 nm (exceeding 95% from 1411–2177 nm), and this performance is maintained for incident angles ranging from 0–30°. The laser-induced damage threshold (LIDT) of the structural film (17.94 J/cm2) is much higher than that of the single layer of SiO2 film (7.06 J/cm2). These results show that the preparation process is an effective technique to obtain a large-scale structural surface for high-power laser systems.

In this paper, four continuous graphene films were successfully prepared by adjusting the nucleation density of graphene. The transparent electromagnetic shielding properties of graphene films under different preparation processes were studied. The results show that the electromagnetic shielding effectiveness of the graphene film does not increase with the increase of the growth thickness. Moreover, the graphene of different thicknesses are mainly absorption shielding, and the reflective shielding effectiveness is less than 0.5dB. The sample #1 is a single-layer graphene film with an optical transmittance of 97.3% and an electromagnetic shielding efficiency of 2.11dB. Its good single-layer structure and fewer defects are the reasons for obtaining higher transparent electromagnetic shielding performance.

In a high-power laser system, when the surface pressure of the optical film caused by laser plasma shock wave is greater than the adhesion per unit area of the film layer, the film will produce mechanical damage, and in serious cases, the whole system may not work. Therefore, studying the formation mechanism of optical film surface pressure caused by laser plasma shock wave and calculating the pressure is the key to ensure the normal operation of high power laser system. In this paper, by studying the relaxation process of shock wave on optical film surface pressure, a theoretical calculation model of shock wave on optical film pressure is established, and the variation law of pressure with different parameters is obtained, which reveals the mechanism of forming the optical film surface pressure. The calculation and simulation results show that the maximum pressure is 108 N m−2 during the laser pulse, and the pressure decreases with the increase of laser pulse time after the pulse, and the total action time of laser plasma and shock wave on the film is in the order of microseconds. The pressure increases with the increase of incident laser energy, focal length of focusing lens and incident laser pulse width, which increases with the decrease of the distance between the film surface and the focal plane of the focusing lens. The pressure changes more obviously with the incident laser energy and the distance between the film surface and the focal plane of the focusing lens than with the focal length of the focusing lens and the incident laser pulse width.

Seasonal alternation impacts the composition of gut microbiota in wild and free-ranging bears, but little is known concerning captive bears. In this study, we investigated the effects of seasonal changes on gut microbiota in captive Asiatic black bears (Ursus thibetanus). Fecal samples of thirteen adult and young were collected at a bile farm in Northeast China between September 2017 and January 2018. The fecal microbiota community was analyzed by sequencing the bacterial 16S V4 hypervariable region using a next-generation sequencing platform. We found that Firmicutes was the predominant phylum in the feces of captive Asiatic black bears. Microbial alpha and beta diversity in both adult and young captive Asiatic black bears was significantly different between the two time points. At the genus level, the relative abundance of Sarcina was increased in all of the captive Asiatic black bears in January, while Streptococcus was decreased in young but not adults. Overall, the composition of gut microbiota was influenced by seasonal changes, but the effect was more pronounced in young captive Asiatic black bears. These findings may help to better understand the roles of captivity and hibernation on shaping the gut microbiota in bears.

Background and aims Hepatitis E virus (HEV), as an emerging zoonotic pathogen, is a leading cause of acute viral hepatitis worldwide, with a high risk of developing chronic infection in immunocompromised patients. However, the global epidemiology of HEV infection has not been comprehensively assessed. This study aims to map the global prevalence and identify the risk factors of HEV infection by performing a systematic review and meta‐analysis. Methods A systematic searching of articles published in Medline, Embase, Web of science, Cochrane and Google scholar databases till July 2019 was conducted to identify studies with HEV prevalence data. Pooled prevalence among different countries and continents was estimated. HEV IgG seroprevalence of subgroups was compared and risk factors for HEV infection were evaluated using odd ratios (OR). Results We identified 419 related studies which comprised of 1 519 872 individuals. A total of 1 099 717 participants pooled from 287 studies of general population estimated a global anti‐HEV IgG seroprevalence of 12.47% (95% CI 10.42‐14.67; I 2 = 100%). Notably, the use of ELISA kits from different manufacturers has a substantial impact on the global estimation of anti‐HEV IgG seroprevalence. The pooled estimate of anti‐HEV IgM seroprevalence based on 98 studies is 1.47% (95% CI 1.14‐1.85; I 2 = 99%). The overall estimate of HEV viral RNA‐positive rate in general population is 0.20% (95% CI 0.15‐0.25; I 2 = 98%). Consumption of raw meat (P = .0001), exposure to soil (P

Background: Intermittent fasting is a popular dietary intervention with perceived relatively easy compliance and is linked to various health benefits, including weight loss and improvement in blood glucose concentrations. The mechanistic explanations underlying the beneficial effects of intermittent fasting remain largely obscure but may involve alterations in the gut microbiota. Objectives: We sought to establish the effects of 1 mo of intermittent fasting on the gut microbiome. Methods: We took advantage of intermittent fasting being voluntarily observed during the Islamic faith-associated Ramadan and sampled feces and blood, as well as collected longitudinal physiologic data in 2 cohorts, sampled in 2 different years. The fecal microbiome was determined by 16S sequencing. Results were contrasted to age- and body weight-matched controls and correlated to physiologic parameters (e.g., body mass and calorie intake). Results: We observed that Ramadan-associated intermittent fasting increased microbiome diversity and was specifically associated with upregulation of the Clostridiales order-derived Lachnospiraceae [no fasting 24.6 ± 13.67 compared with fasting 39.7 ± 15.9 in relative abundance (%); linear discriminant analysis = 4.9, P < 0.001 by linear discriminant analysis coupled with effect size measurements] and Ruminococcaceae [no fasting 13.4 ± 6.9 compared with fasting 23.2 ± 12.9 in relative abundance (%); linear discriminant analysis = 4.7, P < 0.001 by linear discriminant analysis coupled with effect size measurements] bacterial families. Microbiome composition returned to baseline upon cessation of intermittent feeding. Furthermore, changes in Lachnospiraceae concentrations mirrored intermittent fasting-provoked changes in physiologic parameters. Conclusions: Intermittent fasting provokes substantial remodeling of the gut microbiome. The intermittent fasting-provoked upregulation of butyric acid-producing Lachnospiraceae provides an obvious possible mechanistic explanation for health effects associated with intermittent fasting.

This article uses AT89S51 single-chip microcomputer as the CPU of the human body temperature measurement system, uses the MLX90614 sensor to measure the body temperature, assists the use of the HC-SR04 ultrasonic module and the DS18B20 digital temperature sensor to measure the distance between the target and the system and the ambient temperature, and displays the temperature on the LCD system . It is suitable for non-contact measurement in public places, and can detect body temperature quickly and effectively with high accuracy.

Plant fluorescence is too susceptible to interference and unsuitable for plant remote sensing monitor. A plant fluorescence lifetime imaging technology based on plant remote sensing monitor is presented to solve this problem. The technology can be used to analyse plant physiological information for environmental surveillance. The beam expander system was used to expand laser beam at a certain specific wavelengths, and the living plant chlorophyll fluorescence can be excited by this laser beam. Many of the same plant fluorescence signals were excited by continuous laser pulses, and furthermore the start delay time of Intensification Charge Coupled Device was adjusted consecutively in time resolved measurement method. Finally, a complete set of plant continuous fluorescence image was collected by Intensification Charge Coupled Device. The deconvolution can be used to retrieve the high-precision plant fluorescence lifetime of single pixel point in plant continuous fluorescence image. If the plant fluorescence lifetime values from all of pixel points were retrieved, the distribution map of plant fluorescence lifetime can be drawn. The fluorescence lifetime properties of living plants have already been studied preliminarily. The study indicates that the distribution map of plant fluorescence lifetime can more effectively reflect plant chlorophyll content than fluorescence intensity dose. The plant fluorescence lifetime was related to its chlorophyll content in a certain range, and there is a complex and subtle relationship between plant fluorescence lifetime and its physiological information.

Rotavirus infection has emerged as an important cause of complications in organ transplantation recipients and might play a role in the pathogenesis of inflammatory bowel disease (IBD). 6-Thioguanine (6-TG) has been widely used as an immunosuppressive drug for organ recipients and treatment of IBD in the clinic. This study aims to investigate the effects and mode-of-action of 6-TG on rotavirus replication. Human intestinal Caco2 cell line, 3D model of human primary intestinal organoids, laboratory rotavirus strain (SA11) and patient-derived rotavirus isolates were used. We have demonstrated that 6-TG significantly inhibits rotavirus replication in these intestinal epithelium models. Importantly, gene knockdown or knockout of Rac1, the cellular target of 6-TG, significantly inhibited rotavirus replication, indicating the supportive role of Rac1 for rotavirus infection. We have further demonstrated that 6-TG can effectively inhibit the active form of Rac1 (GTP-Rac1), which essentially mediates the anti-rotavirus effect of 6-TG. Consistently, ectopic over-expression of GTP-Rac1 facilitates but an inactive Rac1 (N17) or a specific Rac1 inhibitor (NSC23766) inhibits rotavirus replication. In conclusion, we have identified 6-TG as an effective inhibitor of rotavirus replication via the inhibition of Rac1 activation. Thus, for transplantation patients or IBD patients infected with rotavirus or at risk of rotavirus infection, the choice of 6-TG as a treatment appears rational., Highlights • 6-TG inhibits rotavirus infection. • Rac1, the cellular target of 6-TG, supports rotavirus infection. • 6-TG inhibits the active form of Rac1 (GTP-Rac1) to exert the anti-rotavirus effect.

Interferon-stimulated genes (ISGs) are a group of gene products that coordinately combat pathogen invasions, in particular viral infections. Transcription of ISGs occurs rapidly upon pathogen invasion, and this is classically provoked via activation of the Janus kinase/signal transducer and activator of transcription (JAK–STAT) pathway, mainly by interferons (IFNs). However, a plethora of recent studies have reported a variety of non-canonical mechanisms regulating ISG transcription. These new studies are extremely important for understanding the quantitative and temporal differences in ISG transcription under specific circumstances. Because these canonical and non-canonical regulatory mechanisms are essential for defining the nature of host defense and associated detrimental proinflammatory effects, we comprehensively review the state of this rapidly evolving field and the clinical implications of recently acquired knowledge in this respect., Trends Transcriptional regulation of ISGs defines the state of host anti-pathogen defense. In light of the recently identified regulatory elements and mechanisms of the IFN–JAK–STAT pathway, new insights have been gained into this classical cascade in regulating ISG transcription. A variety of non-canonical mechanisms have been recently revealed that coordinately regulate ISG transcription. With regards to the adverse effects of IFNs in clinic, ISG-based antiviral strategy could be the next promising frontier in drug discovery.

Additional file 1: Table S1. Nutritional analysis of the experimental diet.

Background It has recently been reported that intermittent fasting shapes the gut microbiota to benefit health, but this effect may be influenced to the exact fasting protocols. The purpose of this study was to assess the effects of different daily fasting hours on shaping the gut microbiota in mice. Healthy C57BL/6 J male mice were subjected to 12, 16 or 20 h fasting per day for 1 month, and then fed ad libitum for an extended month. Gut microbiota was analyzed by 16S rRNA gene-based sequencing and food intake was recorded as well. Results We found that cumulative food intake was not changed in the group with 12 h daily fasting, but significantly decreased in the 16 and 20 h fasting groups. The composition of gut microbiota was altered by all these types of intermittent fasting. At genus level, 16 h fasting led to increased level of Akkermansia and decreased level of Alistipes, but these effects disappeared after the cessation of fasting. No taxonomic differences were identified in the other two groups. Conclusions These data indicated that intermittent fasting shapes gut microbiota in healthy mice, and the length of daily fasting interval may influence the outcome of intermittent fasting.

Optical film damage threshold is an important basis for measuring the ability of film to resist laser damage, and laser parameters are the key factors affecting its accurate measurement. The single-factor control variable method was used to establish the the numerical model of laser energy error, the focused spot size error and the damage threshold error, and the M 2 factor and the damage threshold. The theoretical analysis and computer simulation of the energy error, the focused spot size error and the beam quality on the film damage threshold influences. A method based on the Shack-Hartman wave-front detection method is proposed to measure the pulsed laser beam parameters. The working principle is described in detail, and the Shack-Hartman beam shape parameter measurement system is designed. The actual output energy of the laser and the size of the focused spot were measured experimentally, and the uncertainty of the film damage threshold was evaluated according to the statistical principle. The results shows that the energy error and the focused spot error are directly proportional to the damage threshold error, and M 2 is inversely related to the damage threshold. From the thin film sample analysis, the relative uncertainty of the damage threshold measurement is 18.78%. Therefore, studying the influence of laser parameters on the damage threshold provides a direction for obtaining accurate film damage threshold test results.

In order to improve the shielding effectiveness of graphene films, graphene films were prepared by chemical vapor deposition. The effects of hydrogen flow rate, methane flow rate, reaction temperature and reaction time on the electromagnetic shielding properties of the films were investigated. The shielding effectiveness of the film was tested and the preparation process of the film was optimized based on the test results. The results show that when the hydrogen flow rate is 8sccm, the methane flow rate is 15sccm, the reaction temperature is 1030°C, and the reaction time is 30minutes, the shielding effectiveness of the film is 1.2dB (0.3-3000MHz) and the average transmittance is 96%. (400-800nm), the photoelectric comprehensive performance is better.