Characteristics of broadband lightning emissions associated with terrestrial gamma ray flashes

To characterize lightning processes that produce terrestrial gamma ray flashes (TGFs), we have analyzed broadband (<1 Hz to 30 kHz) lightning magnetic fields for TGFs detected by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) satellite in 2004-2009. The majority (96%) of 56 TGF-associated lightning signals contain single or multiple VLF impulses superposed on a slow pulse that reflects a process raising considerable negative charge within 2-6 ms. Some TGF lightning emissions also contain VLF signals that precede any appreciable slow pulse and that we term precursor sferics. The analyses of 9 TGFs related to lightning discharges with location uncertainty <100 km consistently indicate that TGFs are temporally linked to the early portion of the slow process and associated VLF impulses, and not to precursor sferics. The nearly universal presence of a slow pulse suggests that the slow process plays an important role in gamma ray production. In all cases the slow process raises negative charge with a typical mean current moment of +30 kA km. The resulting charge moment change ranges from small values below +10 C km to a maximum of +200 C km, with an average of +64 C km. The current moment waveform extracted from TGF sferics with single or multiple VLF impulses also shows that the slow process initiates shortly before the major TGF-associated fast discharge. These features are generally consistent with the TGF-lightning sequence reported by Lu et al. (2010), suggesting that the majority of RHESSI TGFs are produced during the upward negative leader progression prevalent in normal polarity intracloud flashes

catena-Poly[[(1,10-phenanthroline)lead(II)]bis­(μ-5-chloro-2-hy­droxy­benzoato)]

In the title polymer, [Pb(C7H4ClO3)2(C12H8N2)]n, the Pb(II) ion displays a distorted pseudo-octa­hedral coordination geometry. The metal center is coordinated by six O atoms from four 5-chloro­salicylate ligands and two N atoms from a chelating phenanthroline ligand. The polymeric structure is built up from bridging carboxyl­ate O atoms, forming chains along [100]. The crystal structure is stabilized by π–π inter­actions between the 1,10-phenanthroline and 5-chloro­salicylate ligands, the shortest centroid–centroid separation between neighbouring aromatic rings being 3.652 (1) Å

Monitoring and analysis of STEC in cow manure from a dairy farm and retail fresh beef around Chengdu City

ObjectiveTo understand the carrying status and strain characteristics of STEC strains in cattle and beef in the local area， provide scientific basis for evaluating the STEC pollution status， infection risk， prevention and control strategies in the region， the Shiga toxin producing Escherichia coli （STEC） in the feces of calves and adult cows and feeding environment in a dairy farm around Chengdu， as well as fresh beef from vegetable markets and supermarkets for three years were continuously monitored.MethodsSTEC using fluorescence quantitative PCR method was identified， and drug sensitivity testing using micro broth dilution method was conducted. After sequencing the entire genome of the isolated strain， the MLST type， strain type， serotyping， and virulence gene information were obtained on the EnteroBase database. The stx subtype information was compared using the Abricate software. Perform cgMLST clustering analysis was used by BioNumerics 7.6 software.ResultsFrom 2019 to 2021， a total of 247 cow manure and environmental samples were collected from dairy farms， and 25 STEC strains were isolated， with a detection rate of 10.12%. 294 fresh beef samples were collected and 32 STECs were isolated， with a detection rate of 10.88%. A total of 57 STEC strains were isolated. The STEC strain had the highest resistance rate to ampicillin， reaching 42.11%（24/57）， followed by cefotaxime and cefazolin at 38.60%（22/57）. Multiple resistant strains accounted for 35.09%（20/57）. A total of 30 serotypes were isolated from 57 STEC strains， among which the serotypes that can cause outbreaks include O26：H11， O103：H25， and O145：H12. Through virulence gene analysis， it was found that subtypes with pathogenic risk included stx2a， stx2c， stx2d， stx2e， stx2g， stx2k， as well as eae-STEC and STEC/ETEC heterozygous strains.ConclusionThe pollution of STEC in cow manure from dairy farms and fresh beef from vegetable markets continued to exist from 2019 to 2021. The detection rate of calf feces was 21.43%， which was higher than that of adult cow feces by 0.91%. The STEC detection rate of fresh beef in vegetable markets is significantly higher than that in supermarkets. The drug resistance of strains isolated from cow manure is more severe than that of strains isolated from beef. Some isolated strains have stronger pathogenicity due to carrying strong virulence genes or other pathogenic related genes

MicroRNA-7 inhibits epithelial-to-mesenchymal transition and metastasis of breast cancer cells via targeting FAK expression

10.1371/journal.pone.0041523PLoS ONE78

Optical emissions associated with narrow bipolar events from thunderstorm clouds penetrating into the stratosphere

Narrow bipolar events (NBEs) are signatures in radio signals from thunderstorms observed by ground-based receivers. NBEs may occur at the onset of lightning, but the discharge process is not well understood. Here, we present spectral measurements by the Atmosphere‐Space Interactions Monitor (ASIM) on the International Space Station that are associated with nine negative and three positive NBEs observed by a ground‐based array of receivers. We found that both polarities NBEs are associated with emissions at 337 nm with weak or no detectable emissions at 777.4 nm, suggesting that NBEs are associated with streamer breakdown. The rise times of the emissions for negative NBEs are about 10 μs, consistent with source locations at cloud tops where photons undergo little scattering by cloud particles, and for positive NBEs are ~1 ms, consistent with locations deeper in the clouds. For negative NBEs, the emission strength is almost linearly correlated with the peak current of the associated NBEs. Our findings suggest that ground-based observations of radio signals provide a new means to measure the occurrences and strength of cloud-top discharges near the tropopause.publishedVersio