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International audience; Bioluminescence is a common phenomenon in nature, especially in the deep ocean. The physiological role of bacterial bioluminescence involves protection against oxidative and UV stresses. Yet, it remains unclear if bioluminescence contributes to deep-sea bacterial adaptation to high hydrostatic pressure (HHP). In this study, we constructed a non-luminescent mutant of ΔluxA and its complementary strain c-ΔluxA of Photobacterium phosphoreum ANT-2200, a deep-sea piezophilic bioluminescent bacterium. The wild-type strain, mutant and complementary strain were compared from aspects of pressure tolerance, intracellular reactive oxygen species (ROS) level and expression of ROS-scavenging enzymes. The results showed that, despite similar growth profiles, HHP induced the accumulation of intracellular ROS and up-regulated the expression of ROS-scavenging enzymes such as dyp, katE and katG, specifically in the non-luminescent mutant. Collectively, our results suggested that bioluminescence functions as the primary antioxidant system in strain ANT-2200, in addition to the well-known ROS-scavenging enzymes. Bioluminescence contributes to bacterial adaptation to the deep-sea environment by coping with oxidative stress generated from HHP. These results further expanded our understanding of the physiological significance of bioluminescence as well as a novel strategy for microbial adaptation to a deep-sea environment.

A novel moderately thermophilic heterotrophic bacterium, designated strain 143-21T, was isolated from a deep-sea hydrothermal chimney sample collected from the Central Indian Ridge at a depth of 2 440 m. Phylogenetic analysis indicated that strain 143-21T belongs to the genus Crassaminicella . It was most closely related to Crassaminicella thermophila SY095T (96.79 % 16S rRNA gene sequence similarity) and Crassaminicella profunda Ra1766HT (96.52 %). Genomic analysis showed that strain 143-21T shares 79.79–84.45 % average nucleotide identity and 23.50–29.20 % digital DNA–DNA hybridization with the species of the genus Crassaminicella , respectively. Cells were rod-shaped, non-motile, Gram-positive-staining. Terminal endospores were observed in stationary-phase cells when strain 143-21T was grown on Thermococcales rich medium. Strain 143-21T was able to grow at 30–60 °C (optimum, 50 °C), pH 6.5–8.5 (optimum, pH 7.0) and in 1.0–7.0 % NaCl (w/v; optimum 2.0 %, w/v). Strain 143-21T utilized fructose, glucose, maltose, mannose, ribose, N-acetyl-d-(+)-glucosamine and casamino acids, as well as amino acids including glutamate, lysine, histidine and cysteine. The main fermentation products from glucose were acetate (2.07 mM), H2 and CO2. It did not reduce elemental sulphur, sulphate, thiosulphate, sulphite, fumarate, nitrate, nitrite and Fe (III). The predominant cellular fatty acids were C14 : 0 (48.8 %), C16 : 0 (12.9 %), and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c; 10.2 %). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, as well as two unidentified phospholipids and four unidentified aminolipids. No respiratory quinones were detected. Based on its phylogenetic analysis and physiological characteristics, strain 143-21T is considered to represent a novel species of the genus Crassaminicella , for which the name Crassaminicella indica sp. nov. is proposed. The type strain is strain 143-21T (=DSM 114408T= MCCC 1K06400T).

International audience; Alteration of respiratory components as a function of pressure is a common strategy developed in deep-sea microorganisms, presumably to adapt to high hydrostatic pressure (HHP). While the electron transport chain and terminal reductases have been extensively studied in deepsea bacteria, little is known about their adaptations for ATP generation. In this study, we showed that the deep-sea bacterium Photobacterium profundum SS9 exhibits a more pronounced piezophilic phenotype when grown in minimal medium supplemented with glucose (MG) than in the routinely used MB2216 complex medium. The intracellular ATP level varied with pressure, but with opposite trends in the two culture media. Between the two ATPase systems encoded in SS9, ATPase-I played a dominant role when cultivated in MB2216, whereas ATPase-II was more abundant in the MG medium, especially at elevated pressure when cells had the lowest ATP level among all conditions tested. Further analyses of the ∆atpI, ∆atpE1 and ∆atpE2 mutants showed that disrupting ATPase-I induced expression of ATPase-II and that the two systems are functionally redundant in MB2216. Collectively, we provide the first examination of the differences and relationships between two ATPase systems in a piezophilic bacterium, and expanded our understanding of the involvement of energy metabolism in pressure adaptation.

In this article, a novel p-GaN high-electron-mobility transistor (HEMT) with a built-in Schottky barrier diode (SBD) is proposed and investigated by TCAD simulation. The anode contact of the integrated SBD is isolated from the ohmic contact of the source electrode by a p-GaN isolation region. The cathode of the SBD is connected to the drain electrode. In the proposed Schottky barrier diode/HEMT (SB-HEMT), a channel under the p-GaN isolation region is turned on during forward conduction to further reduce the specific on-resistance ( $R_{{on},sp}$ ). With a minimum sacrifice on $R_{{on},sp}$ , the reverse on-state voltage, $V_{R-{on}}$ (at a current density of 50 mA/mm), for the SB-HEMT is reduced by 33% (from 2.43 to 1.62 V) when compared with a conventional HEMT (C-HEMT). Compared with the C-HEMT with a separate on-chip SBD (C-HEMT/SBD), the SB-HEMT shows much better trade-off between $V_{R-{on}}$ and $R_{{on},sp}$ . The total switching loss ( $E_{total}$ ) of the proposed SB-HEMT with resistive load is lower than that of the C-HEMT and is reduced by up to 21% when compared with that of the C-HEMT/SBD with different area ratio between the HEMT and SBD regions.

Conventional di/dt and dv / dt control and gate protection techniques for gallium nitride (GaN) power transistors usually employ external controllers, isolation circuits, discrete pull-up, and pull-down resistors. With large number of components, power modules become more complex and may introduce additional parasitic. Gate driver ICs with segmented output stages and dynamic gate driving have been reported previously to be effective in simultaneously suppressing gate ringing and overshoot voltage while maintaining fast switching speed. However, the programming for dynamic gate driving is rather complicated, requiring the user to load a sequence of driving patterns obtained from trial and error ahead of time. This article presents a gate driver IC for E-mode GaN power transistors with seven segmented output stages. More importantly, it offers a simplified programming method for the dynamic gate driving pattern. The optimal gate drive pattern can be defined by simply adjusting one external bias resistor. The proposed method eliminates the complex trial and error digital control, and can potentially promoting the wider acceptance of dynamic gate driving by the industry. The timing resolution for the gate drive pattern can be varied in steps from 0.5 to 5 ns. It can also be used to drive many commercially available GaN power transistors.

BackgroundNeuropsychiatric symptoms (NPSs) belong to a category of non-motor symptoms of Parkinson's disease (PD), which seriously compromise the quality of life and prognosis of PD. This study focused on the correlations between NPSs, free radicals, neuroinflammatory factors, and neuropathological proteins in cerebrospinal fluid (CSF) in patients with PD, aiming to provide insights into the potential mechanisms and therapeutic target for PD with NPSs (PD-NPSs).MethodsIn total, 129 patients with PD were enrolled and assessed by the Neuropsychiatric Symptoms Inventory (NPI); they were divided into the PD-NPSs group (75 patients) and PD with no NPSs (PD-nNPSs) group (54 patients). The levels of hydrogen peroxide (H2O2) and nitric oxide (NO), and hydroxyl radical (·OH), anti-oxidative enzyme, neuroinflammatory factors, and neuropathological proteins in CSF from patients with PD were measured. The levels of the above variables were compared between PD-NPSs and PD-nNPSs groups, and correlation analyses among the above variables were conducted.Results(1) The levels of H2O2 and NO in CSF from the PD-NPSs group were significantly elevated compared with the PD-nNPSs group (p = 0.001), and NPI score positively correlated with the levels of H2O2 and NO (r = 0.283, P = 0.001; r = 0.231, P = 0.008). Reversely, total superoxide dismutase (tSOD) activity in CSF from the PD-NPSs group was significantly reduced compared with the PD-nNPSs group (p = 0.011), and negatively correlated with NPI score (r = −0.185, p = 0.036). (2) The tumor necrosis factor (TNF)-α level in CSF from the PD-NPSs group was significantly decreased compared with the PD-nNPSs group (p = 0.002) and negatively correlated with NPI score (r = −0.211, p = 0.016). (3) The total tau (T-tau) level in CSF from the PD-NPSs group was significantly higher than in the PD-nNPSs group (p = 0.014) and positively correlated with the NPI score (r = 0.167, p = 0.060). (4) The levels of H2O2 and NO positively correlated with the T-tau level in CSF from the PD-NPSs group (r = 0.183, p = 0.039; r = 0.251, P = 0.004), and the levels of TNF-α and T-tau showed a negative correlation (r = −0.163, p = 0.067).ConclusionOxidative distress characterized by the elevations of H2O2 and NO levels may closely correlate with the neurodegeneration in brain regions related to PD-NPSs. Thus, therapeutic antioxidants may become an important target for PD-NPSs therapy.

Endosomal sorting complex required transport (ESCRT) III proteins are essential for membrane remodeling and repair across all domains of life. Eukaryotic ESCRT-III and the cyanobacterial homologs PspA and Vipp1/Imm30 remodel membrane into vesicles, rings, filaments and tubular rods structures. Here our microscopy analysis showed that multicellular bacteria, referred to as magnetoglobules, possess multiple compartments including magnetosome organelles, polyphosphate granules, vesicles, rings, tubular rods, filaments and MVB-like structures. Therefore, membrane remodeling protein PspA might be required for the formation of these compartments, and contribute to the morphogenesis and evolution of multicellularity. To assess these hypotheses, we sequenced nine genomes of magnetoglobules and found a significant genome expansion compared to unicellular magnetotactic bacteria. Moreover, PspA was ubiquitous in magnetoglobules and formed a distinct clade on the tree of eubacterial and archaeal ESCRT-III. The phylogenetic feature suggested the evolution of magnetoglobules from a unicellular ancestor of deltaproteobacterium. Hetero-expression of ellipsoidal magnetoglobulepspA2gene alone inEscherichia coliresulted in intracellular membrane aggregation. GFP fusion labeling revealed polar location of PspA2 in rod-shaped unicells and regular interval location in filamentous cells. Cryo-electron tomography analysis showed filament bundle, membrane sacculus, vesicles and MVB-like structure in the cells expressing PspA2. Moreover, electron-dense area with a similar distribution as GFP-PspA2 foci in filamentous cells changed the inward orientation of the septum, which might interfere with the cell division. Collectively, these results show the membrane remodeling function of magnetoglobule PspA proteins, which may contribute to morphogenesis and the evolution of multicellularity of magnetotactic bacteria.

Full-length lower limb x-rays are used to diagnose and plan surgical procedures, such as Total Knee Arthroplasty (TKA) and High Tibial Osteotomy (HTO). Due to the size limitation of digital radiography (DR), panoramic x-ray images cannot be obtained in a single exposure, necessitating multiple exposures and image stitching. In favor of manually constructing full-length x-ray images, we propose a new feature-based automated method for stitching together x-ray images. This new method is based on Canny algorithm, which detects and aligns bone edges before fusing them using a Wavelet form domain. Twenty-eight sets of lower limb x-ray images obtained from our hospital have been stitched and evaluated. The hip, knee, and ankle (HKA) angle was computed in two different ways then compared to manually stitched x-ray images by an expert. The stitching time was only three seconds, and the P-value was P = 0.974, and an accuracy rate of 100% was found. This method demonstrated greater precision and speed than both manually stitched x-ray images and previously published methods.

In this paper, in order to investigate the size effect on the flexural behavior of ultra-high-performance concrete (UHPC) beams, two groups UHPC beams with sizes of, (small) and (large), were tested through four-point bending test. Each group consists of four UHPC beams with different rebar type and reinforcement ratio. The experimental results showed that the flexural strength, normalized deflection, and fracture toughness of HRB400 steel reinforced UHPC beams was not affected by size effect. The normalized deflection at ultimate bearing capacity of GFRP reinforced UHPC beams is affected by size effect, but no size effect was shown for whole deflection process. The flexural strength and fracture toughness of GFRP reinforced UHPC beams changed from having size effect to no size effect with the increase of reinforcement ratio. Furthermore, the maximum crack width, number of cracks and average crack spacing of both UHPC beams were sensitive to the size of specimen, while no significant size effect was shown for ductility of both UHPC beams.

A miniaturized atomic spin-exchange relaxation-free (SERF) co-magnetometer measures angular velocity using a balanced polarimetry technique which is easily affected by the laser power. A laser power closed-loop control system is usually used to suppress the fluctuation of the laser power. Although this method can greatly eliminate the fluctuation of the in-loop laser power (the feedback laser), it cannot fully eliminate the fluctuation of the out-of-loop laser power (the signal measurement laser). This leads to SERF gyroscope laser power error, which reduces the inertial measurement accuracy. In this paper, the influence mechanism of the split ratio (the ratio of the in-loop laser power to the out-of-loop laser power) on the out-of-loop laser power control accuracy is analyzed by establishing a laser power transmission model inside and outside the loop. Moreover, a method is developed to improve the out-of-loop laser power stability by optimizing the split ratio. Comparative experiments showed that the relative Allan standard deviation of the out-of-loop laser power decreased from 5.48 × 10−6 to 2.62 × 10−6 at 100 s, and decreased by an order of magnitude from 1.76 × 10−5 to 3.30 × 10−6 at 1000 s. Correspondingly, the rate ramp coefficient in the Allan standard deviation curve of the SERF gyroscope test data decreased from 1.312 [(°/h)/h] to 0.246 [(°/h)/h]. And the bias stability increased from 0.032 °/h to 0.019 °/h. Therefore, the proposed method can improve the long-term stability of the probe laser power and effectively suppress the laser power error of the SERF gyroscope.

An accurate method for the evaluation of breakdown voltages (BVs) in the superjunction-like (SJ-like) power devices is presented. This brief investigates the conventional SJ (c-SJ), the insulator pillar SJ (I-SJ), and the high-permittivity ( $\text{H}{k}$ ) structures. Based on the numerical calculations of the electric field line (EFL) distribution, the electric field profiles along the EFLs can be accurately obtained. This ensures the accurate determination of the impact ionization integrals and BV. The technology computer-aided design (TCAD) simulations confirm the validity of the proposed method. The proposed method could be of great significance for the optimization of the specific ON-resistance ( ${R} _{ \text {ON,sp}}$ ) and could provide a better understanding of the SJ-like power devices.

Gallium nitride (GaN) power transistors have attracted significant interest in the power electronics industry over the past decade as the next-generation power semiconductor devices. GaN power transistors are suitable for high power and high frequency applications due to their higher electron mobility, temperature tolerance, electrical conductivity, critical breakdown electric field, and breakdown voltage compared to the conventional silicon-based transistors and other wide bandgap (WBG) power transistors. In particular, GaN-on-silicon (GaN-on-Si) technology has opened up the possibility of manufacturing high-performance, low-cost WBG power devices in silicon-compatible fabrication facilities. The first GaN power transistor structure to be developed was the normally-ON depletion mode (D-mode) device. It relies on the highly mobile two-dimension electron gas (2DEG) at the GaN/AlGaN epitaxial layers’ interface to provide very low on-resistance. The normally-OFF enhancement mode (E-mode) GaN power transistor soon became available by controlling the 2DEG using various gate structures. This paper provides a review of the developments of GaN power transistors followed by a survey on current state-of-the-art GaN power technologies and applications, including comparisons between GaN growth substrates and developments of enhancement mode (E-mode) device structures and their process techniques. Moreover, developments of power module designs are also addressed, including gate driver designs and their requirements, and packaging techniques for power transistors and power modules.

A new lateral power metal-oxide-semiconductor field-effect transistor (MOSFET) with dual conduction paths and high- ${k}$ passivation is proposed. The high- ${k}$ passivation enables the dual conduction paths to realize the double reduced surface field (RESURF) action and facilitates the formation of an accumulation layer during forward conduction. The proposed device offers a 42% reduction in specific on-resistance ( ${R}_{{ON},{SP}}{)}$ when compared to a similar size baseline device with the same breakdown voltage (BV). The technology computer-aided design (TCAD) simulation results, based on a $0.5~\mu \text{m}$ bipolar-CMOS-DMOS (BCD) compatible process, show that the proposed device is able to provide a ${R}_{{ON},{SP}}$ as low as 0.28 $\text{m}\Omega \cdot $ cm2 with a BV of 92 V.

The mechanism underlying the hypoglycemic effect of the simultaneous use of metformin and anthocyanin-rich foods is not yet clear. Hence, the effects and possible mechanisms of action of these substances, alone and in combination, were evaluated in insulin-resistant HepG2 cells and a diabetic mouse model. The results indicated that anthocyanin and metformin had a significant synergistic effect on glucose consumption (CI0.9) compared with metformin alone in HepG2 cells. In the mouse model, combined treatment (50 and 100 mg/kg metformin + anthocyanin groups) demonstrated synergistic restorative effects on the blood glucose level, insulin resistance, and organ damage in the liver, pancreas, and ileum. Additionally, combined metformin and anthocyanin treatment suppressed protein tyrosine phosphatase 1B expression and regulated the PI3K/AKT/GSK3β pathway. Combined treatment also altered the gut microbial composition and structure by increasing the relative abundance of beneficial bacteria and the short-chain fatty acid content. These results suggest that the use of anthocyanins can enhance the efficacy of metformin treatment for hyperglycemia and provide a reference for further clinical research regarding nutrition and supplementary treatment.

Deep-sea hydrothermal vents are known as chemosynthetic ecosystems. However, high temperature vents emit light that hypothetically can drive photosynthesis in this habitat. Metagenomic studies have sporadically reported the occurrence of phototrophic populations such as cyanobacteria in hydrothermal vents. To determine how geographically and taxonomically widespread phototrophs are in deep-sea hydrothermal vents, we collected samples from three niches in a hydrothermal vent on the Southwest Indian Ridge and carried out an integrated metagenomic analysis. We determined the typical community structures of microorganisms found in active venting fields and identified populations of known potential chlorophototrophs and retinalophototrophs. Complete chlorophyll biosynthetic pathways were identified in all samples. By contrast, proteorhodopsins were only found in active beehive smoker diffusers. Taxonomic groups possessing potential phototrophy dependent on semiconductors present in hydrothermal vents were also found in these samples. This systematic comparative metagenomic study reveals the widespread distribution of phototrophic bacteria in hydrothermal vent fields. Our results support the hypothesis that the ocean is a seed bank of diverse microorganisms. Geothermal vent light may provide energy and confer a competitive advantage on phototrophs to proliferate in hydrothermal vent ecosystems. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42995-021-00121-y.

Dead-times are necessary in switching output stage to avoid shoot-through current between the high side (HS) and the low side (LS) power transistors. However, excessively long dead-times can lead to unwanted reverse conduction and power loss. Sensing the duration of reverse conductions are especially difficult for high-voltage enhancement mode ( e -mode) gallium nitride (GaN) HEMTs due to their fast switching speed. High-precision sensing circuits are required for dead-time correction as the load current changes and to withstand large voltage swings. Traditional CMOS-based sensing circuits (e.g. standard logic gates) are not suitable for GaN-based converters as they can only handle limited voltage ranges. In addition, severe undershoots (up to -4 V) may damage the sensing circuit. Here, a gate driver IC for e -mode GaN power output stages capable of detecting the presence of reverse conduction with a best resolution of 0.66 ns, a dead-time adjustment resolution of 0.33 ns, and with on-chip closed-loop control is presented. In addition, a novel reverse conduction sensing circuit that can accommodate the large voltage swings at the switching node (SW) is also described.

A novel moderately thermophilic, anaerobic, heterotrophic bacterium (strain SY095T) was isolated from a hydrothermal vent chimney located on the Southwest Indian Ridge at a depth of 2730 m. Cells were Gram-stain-positive, motile, straight to slightly curved rods forming terminal endospores. SY095T was grown at 45–60 °C (optimum 50–55 °C), pH 6.0–7.5 (optimum 7.0), and in a salinity of 1–4.5 % (w/v) NaCl (optimum 2.5 %). Substrates utilized by SY095T included fructose, glucose, maltose, N-acetyl glucosamine and tryptone. Casamino acid and amino acids (glutamate, glutamine, lysine, methionine, serine and histidine) were also utilized. The main end products from glucose fermentation were acetate, H2 and CO2. Elemental sulphur, sulphate, thiosulphate, sulphite, fumarate, nitrate, nitrite and Fe(III) were not used as terminal electron acceptors. The predominant cellular fatty acids were C14 : 0 (60.5%) and C16 : 0 (7.6 %). The main polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, five unidentified phospholipids and two unidentified aminophospholipids. No respiratory quinones were detected. The chromosomal DNA G+C content was 30.8 mol%. The results of phylogenetic analysis of the 16S rRNA gene sequences indicated that SY095T was closely related to Crassaminicella profunda Ra1766HT (95.8 % 16S rRNA gene sequence identity). SY095T exhibited 78.1 % average nucleotide identity (ANI) to C. profunda Ra1766HT. The in silico DNA–DNA hybridization (DDH) value indicated that SY095T shared 22.7 % DNA relatedness with C. profunda Ra1766HT. On the basis of its phenotypic, genotypic and phylogenetic characteristics, SY095T is suggested to represent a novel species of the genus Crassaminicella , for which the name Crassaminicella thermophila sp. nov. is proposed. The type strain is SY095T (=JCM 34213=MCCC 1K04191). An emended description of the genus Crassaminicella is also proposed.

The discovery of new viruses is important for predicting their potential threats to the health of humans and other animals. A novel picornavirus was identified from oral, throat, and anal swab samples collected from belugas (Delphinapterus leucas), from Dalian Sun Asia Tourism Holding Co., China, between January and December 2018, using a metagenomics approach. The genome of this novel PicoV-HMU-1 strain was 8197 nucleotides (nt) in length, with a open reading frame (from 1091 to 8074 nt) that encoded a polyprotein precursor of 2328 amino acids. Moreover, the genomic length and GC content of PicoV-HMU-1 were within the ranges found in other picornaviruses, and the genome organization was also similar. Nevertheless, PicoV-HMU-1 had a lower amino acid identity and distinct host species compared with other members of the Picornaviridae family. Phylogenetic trees were constructed based on the P1 and 3D amino acid sequences of PicoV-HMU-1 along with representative members of the Picornaviridae family, which showed that PicoV-HMU-1 was related to unclassified bat picornaviruses groups. These findings suggest that the PicoV-HMU-1 strain represents a potentially novel genus of picornavirus. These data can enhance our understanding of the picornavirus genetic diversity and evolution.

International audience; Crassaminicella sp. 143-21, a putative new species isolated from deep-sea hydrothermal vent chimney on the Central Indian Ridge (CIR), is an anaerobic, thermophilic and rod-shaped bacterium belonging to the family Clostridiaceae. In this study, we present the complete genome sequence of strain 143-21, comprising 2,756,133 bp with a G + C content of 31.1%. In total, 2427 protein coding genes, 121 tRNA genes and 33 rRNA genes were obtained. Genomic analysis of strain 143-21 revealed that numerous genes related to organic matter transport and catabolism, including peptide transport, amino acid transport, saccharide transport, ethanolamine transport and corresponding metabolic pathways. Further, the genome contains a large proportion of genes involved in translation, ribosomal structure, and signal transduction. These genes might facilitate microbial survival in deep-sea hydrothermal vent environment. The genome of strain 143-21 will be helpful for further understanding its adaptive strategies in the deep-sea hydrothermal vent environment.

At high altitude, wastewater aeration efficiency is low, which is detrimental to nitrification in conventional biological nitrogen removal. The combined partial nitritation and anaerobic ammonium oxidation (CPNA) process requires little oxygen and can be appropriate in low-pressure conditions. As such, in this study, we investigated the effect of air pressure on CPNA using a laboratory-scale reactor. We found that low air pressure promoted the removal of total inorganic nitrogen (TIN), achieving a TIN removal rate of 43,000 mg·N/(kg·VSS·d). The secretion of extracellular polymeric substances under low air pressure was not significantly different from that under ordinary air pressure, indicating no adverse effects on microbial aggregation ability, stability, or settleability. The abundance of aerobic ammonia-oxidizing bacteria (AeAOB) increased from 0.2% to 5.6%, and the activity of anaerobic ammonia-oxidizing bacteria (AnAOB) enhanced, giving AeAOB and AnAOB a competitive advantage over nitrite-oxidizing bacteria, thus forming a microbial community structure favorable to the CPNA process. Our further analysis of the results of batch tests in serum bottles confirmed the positive effect of low air pressure on the anaerobic ammonium oxidation (anammox) process, with a 28.5% ± 1.9% improvement in the specific anammox rate at 70 kPa compared with 100 kPa. AnAOB activity increased, which was reflected in the intracellular heme content increasing from 0.56 ± 0.18 μmol/(g·VSS) at 100 kPa to 2.56 ± 0.20 μmol/(g·VSS) at 70 kPa. We clarified the CPNA-process-promoting effect of low air pressure, which shows potential for nitrogen removal in high-altitude regions.

A hyperthermophilic, strictly anaerobic archaeon, designated strain SY113T, was isolated from a deep-sea hydrothermal vent chimney on the Southwest Indian Ridge at a water depth of 2770 m. Enrichment and isolation of strain SY113T were performed at 85 °C at 0.1 MPa. Cells of strain SY113T were irregular motile cocci with peritrichous flagella and generally 0.8–2.4 µm in diameter. Growth was observed at temperatures between 50 and 90 °C (optimum at 85 °C) and under hydrostatic pressures of 0.1–60 MPa (optimum, 27 MPa). Cells of SY113T grew at pH 4.0–9.0 (optimum, pH 5.5) and a NaCl concentration of 0.5–5.5 % (w/v; optimum concentration, 3.0 % NaCl). Strain SY113T was an anaerobic chemoorganoheterotroph and grew on complex proteinaceous substrates such as yeast extract and tryptone, as well as on maltose and starch. Elemental sulphur stimulated growth, but not obligatory for its growth. The G+C content of the genomic DNA was 55.0 mol%. Phylogenetic analysis of the 16S rRNA sequence of strain SY113T showed that the novel isolate belonged to the genus Thermococcus . On the basis of physiological characteristics, average nucleotide identity values and in silico DNA–DNA hybridization results, we propose a novel species, named Thermococcus aciditolerans sp. nov. The type strain is SY113T (=MCCC 1K04190T=JCM 39083T).

Hadal trenches are the deepest but underexplored ecosystems on the Earth. Inhabiting the trench bottom is a group of micro-organisms termed obligate piezophiles that grow exclusively under high hydrostatic pressures (HHP). To reveal the genetic and physiological characteristics of their peculiar lifestyles and microbial adaptation to extreme high pressures, we sequenced the complete genome of the obligately piezophilic bacterium Moritella yayanosii DB21MT-5 isolated from the deepest oceanic sediment at the Challenger Deep, Mariana Trench. Through comparative analysis against pressure sensitive and deep-sea piezophilic Moritella strains, we identified over a hundred genes that present exclusively in hadal strain DB21MT-5. The hadal strain encodes fewer signal transduction proteins and secreted polysaccharases, but has more abundant metal ion transporters and the potential to utilize plant-derived saccharides. Instead of producing osmolyte betaine from choline as other Moritella strains, strain DB21MT-5 ferments on choline within a dedicated bacterial microcompartment organelle. Furthermore, the defence systems possessed by DB21MT-5 are distinct from other Moritella strains but resemble those in obligate piezophiles obtained from the same geographical setting. Collectively, the intensive comparative genomic analysis of an obligately piezophilic strain Moritella yayanosii DB21MT-5 demonstrates a depth-dependent distribution of energy metabolic pathways, compartmentalization of important metabolism and use of distinct defence systems, which likely contribute to microbial adaptation to the bottom of hadal trench.

Hadal trenches are the deepest but underexplored ecosystems on the Earth. Inhabiting the trench bottom is a group of micro-organisms termed obligate piezophiles that grow exclusively under high hydrostatic pressures (HHP). To reveal the genetic and physiological characteristics of their peculiar lifestyles and microbial adaptation to extreme high pressures, we sequenced the complete genome of the obligately piezophilic bacterium Moritella yayanosii DB21MT-5 isolated from the deepest oceanic sediment at the Challenger Deep, Mariana Trench. Through comparative analysis against pressure sensitive and deep-sea piezophilic Moritella strains, we identified over a hundred genes that present exclusively in hadal strain DB21MT-5. The hadal strain encodes fewer signal transduction proteins and secreted polysaccharases, but has more abundant metal ion transporters and the potential to utilize plant-derived saccharides. Instead of producing osmolyte betaine from choline as other Moritella strains, strain DB21MT-5 ferments on choline within a dedicated bacterial microcompartment organelle. Furthermore, the defence systems possessed by DB21MT-5 are distinct from other Moritella strains but resemble those in obligate piezophiles obtained from the same geographical setting. Collectively, the intensive comparative genomic analysis of an obligately piezophilic strain Moritella yayanosii DB21MT-5 demonstrates a depth-dependent distribution of energy metabolic pathways, compartmentalization of important metabolism and use of distinct defence systems, which likely contribute to microbial adaptation to the bottom of hadal trench.

Colorectal cancer (CRC) is one of the most common cancer in the world. The first line chemotherapeutic agent, 5-fluorouracil (5-FU), plays a predominant role in the clinical treatment of CRC. However, with the wide use of 5-FU, more and more CRC patients have been obtaining drug resistance to 5-FU, which leads to a large amount of treatment failures. One of the effective strategies to overcome this obstacle is to find bioactive natural products from traditional medicine. In our previous work, Sanguisorba officinalis L. was found to exert a strong anti-proliferative activity against 5-FU-senstive/resistant CRC cells. Therefore, several compounds were isolated from this herb and screened for their anti-CRC effects to find promising compounds. Among them, a triterpenoid compound named 3β-[(α-l-arabinopyranosyl) oxy]-urs-12,18(19)-dien-28-oic acid β-d-glucopyranosyl ester (AGE), showed strong activity against both 5-FU-senstive and resistant CRC cells. In order to further study the mechanism of AGE on CRC cells, flow cytometer analysis, mitochondrial membrane potential (MMP) measurement, Western blotting, and RT-PCR assays were performed. Results demonstrated that AGE induced cell death by apoptosis pathway and autophagy, and inhibited cell proliferation via cell cycle arrest in G0-G1 phase mediated by Wnt signaling pathway. Therefore, AGE may be a potential bioactive compound for CRC treatment in clinic.

Conventional insulated gate bipolar transistor (IGBT) current sensing and protection techniques usually employ discrete sensors, such as lossy shunt resistors, and may involve accessing the high-voltage collector load of the IGBT. This would normally present difficulties for integration. This paper presents an IGBT gate driver IC with a collector current sensing circuit and an on-chip CPU for local data processing. This IC is prototyped using a TSMC 0.18 μm 40 V BCD Gen-2 process. The collector current sensing technique is based on the unique Miller plateau relationship between the gate current and collector current ( $I_{C}$ and $I_{G}$ ) for a particular gate resistance ( $R_{G}$ ). It allows a cycle-by-cycle measurement of IC during both turn- on and turn- off transients without any extra discrete components. The temperature variation is compensated internally by the on-chip CPU using polynomial curve fitting. This technique only monitors the low-voltage signal at the gate terminal, without the need to handle any high-voltage signal on the collector/load side. Measurements using a double pulse test setup show an accuracy of ±0.5 A over the current ranges of 1–30 A for turn- on and 1–50 A for turn- off from 25 to 75 °C.

Background The Mariana Trench is the deepest known site in the Earth’s oceans, reaching a depth of ~ 11,000 m at the Challenger Deep. Recent studies reveal that hadal waters harbor distinctive microbial planktonic communities. However, the genetic potential of microbial communities within the hadal zone is poorly understood. Results Here, implementing both culture-dependent and culture-independent methods, we perform extensive analysis of microbial populations and their genetic potential at different depths in the Mariana Trench. Unexpectedly, we observed an abrupt increase in the abundance of hydrocarbon-degrading bacteria at depths > 10,400 m in the Challenger Deep. Indeed, the proportion of hydrocarbon-degrading bacteria at > 10,400 m is the highest observed in any natural environment on Earth. These bacteria were mainly Oleibacter, Thalassolituus, and Alcanivorax genera, all of which include species known to consume aliphatic hydrocarbons. This community shift towards hydrocarbon degraders was accompanied by increased abundance and transcription of genes involved in alkane degradation. Correspondingly, three Alcanivorax species that were isolated from 10,400 m water supplemented with hexadecane were able to efficiently degrade n-alkanes under conditions simulating the deep sea, as did a reference Oleibacter strain cultured at atmospheric pressure. Abundant n-alkanes were observed in sinking particles at 2000, 4000, and 6000 m (averaged 23.5 μg/gdw) and hadal surface sediments at depths of 10,908, 10,909, and 10,911 m (averaged 2.3 μg/gdw). The δ2H values of n-C16/18 alkanes that dominated surface sediments at near 11,000-m depths ranged from − 79 to − 93‰, suggesting that these sedimentary alkanes may have been derived from an unknown heterotrophic source. Conclusions These results reveal that hydrocarbon-degrading microorganisms are present in great abundance in the deepest seawater on Earth and shed a new light on potential biological processes in this extreme environment. Electronic supplementary material The online version of this article (10.1186/s40168-019-0652-3) contains supplementary material, which is available to authorized users.

A trench-gate field stop insulated gate bipolar transistor (TFS-IGBT) with a novel hybrid ${p} ^{+}/{n}$ collector structure is proposed to enhance the trade-off relationship between the on-state voltage drop ( ${V} _{\mathrm{ on}}$ ) and the turn-off energy loss ( ${E} _{\mathrm{ off}}$ ). The proposed hybrid collector structure consists of a ${p} ^{+}/{n}$ layer between the ${p} ^{+}$ collector and the field stop layer. During turn-on, the ${p} ^{+}$ regions in the hybrid ${p} ^{+}/{n}$ layer provide high carrier injection efficiency. During turn-off transient, the ${n}$ -regions in the hybrid ${p} ^{+}/{n}$ collector provide fast carrier extraction paths for holes. 2-D numerical simulations comparing a conventional TFS-IGBT, an injection efficiency controlled IGBT with the proposed hybrid ${p} ^{+}/{n}$ collector TFS-IGBT (HC-IGBT) having similar device structures show that for a 1.2 kV rating and with ${V} _{\mathrm{ on}}$ at 1.5 V, the HC-IGBT has an advantage in ${E} _{\mathrm{ off}}$ reduction by 69% and 22%, respectively. Finally, backside mask alignment is not needed for fabricating the proposed hybrid ${p} ^{+}/{n}$ collector structure.

The application of a segmented gate driver (SGD) to detect aging and provide automated compensation for SiC MOSFETs is presented. By dynamically modifying the gate resistance during switching transients, we can stretch the Miller plateau (MP) duration. The MP level is used as an indicator for the health condition of the SiC power MOSFET. A digital control circuit analyzes the aging effect and provides a control signal to an integrated boost converter, which powers the gate drive voltage. In this manner, the gate drive voltage can be adjusted to compensate for changes in the MOSFET performance. The same SGD can also be used to suppress gate ringing to protect the SiC power device against over/undershoot damage. This is of particular importance at elevated gate voltage.

Compact liquid cooled gallium nitride (GaN) intelligent power modules (IPMs) are fabricated using direct bonding methods. A half bridge module with 15 A GaN high electron mobility transistors (HEMTs) is flip-chip bonded on active metal brazed (AMB) substrates using pressureless nanosilver sintering. The AMB substrates are pre-brazed on a copper liquid cooler. The geometries of the AMB substrates and the GaN IPMs are determined based on thermal simulations using finite element analysis (FEA). The prototype GaN IPMs are tested in a buck converter configuration. The module temperatures are below 35 °C for up to 35 W of output power. The proposed process flow offers a simple IPM packaging solution to power semiconductor companies using prefabricated liquid coolers with brazed AMB substrates from automotive parts manufacturers.

To suppress excessive gate voltage swings during switching, a resistance is normally used to limit the charging rate of the gate capacitance (C G ). Modern solutions, such as segmented gate drivers, can be used to dynamically control the gate resistance R G to minimize ringing while maintaining the fast-switching speed of the transistor. The timing or dynamic pattern of the gate resistance is critical in the optimization of the device and circuit performance. Traditionally, this gate drive pattern is obtained via a trial-and-error or iterative procedure. This paper proposes a method to automatically determine the timing intervals by monitoring the gate signal (V GATE ) through slope sensing with analog filter and subsequent mixed-signal processing. The output timing indicator (T SEG ) is then fed back to the segmented gate driver IC to achieve automatic adjustments of the dynamic driving pattern. The proposed system is able to determine the optimum T SEG for dynamic gate driving. For the SiC power MOSFET used in our testing, segmented R G driving between 2.5 and 10 Ω does not hinder the switching speed, while keeping the undershoot of the SiC module to be within 1 V or 5% of the total applied gate voltage.

Intelligent power modules (IPMs) are critical components within electric vehicle (EV) power inverters that require effective liquid cooling. IPM manufacturers are constantly evolving their designs in lockstep with advancements in switching transistor technology to deliver more power with increased efficiency. In particular, the imminent arrival of new IPMs based on wide-bandgap semiconductors poses new thermal challenges due to smaller die areas and increased heat fluxes. The question arises whether the traditional liquid cooling strategies will be sufficient to cool the next generation of EV IPMs as semiconductor technology transitions from Si IGBTs, to SiC MOSFETs and GaN power HEMTs, with progressively decreasing die areas. In this paper, this question is explored through an analytical solution of the heat equation in a representative model of a typical EV IPM heat exchanger (HX). It is shown that there exists a practical thermal limit to traditional EV IPM HXs which must be addressed by IPM and automotive parts manufacturers together. Thermal benchmarking experiments, supported by numerical simulations, of two commercially available IPMs are performed, confirming no violations of the derived thermal limit.

Background Helicobacter pylori (H. pylori) infection has become an international public health problem, and antibiotic-based triple or quadruple therapy is currently the mainstay of treatment. However, the effectiveness of these therapies decreases due to resistance to multiple commonly used antibiotics. Sanguisorba officinalis L. (S. officinalis), a traditional Chinese medicine clinically used for hemostasis and treatment of diarrhea, has various pharmacological activities. In this study, in vitro antimicrobial activity was used for the preliminary evaluation of S. officinalis against H. pylori. And a pharmacology analysis approach was also utilized to elucidate its underlying mechanisms against H. pylori infection. Methods Micro-broth dilution method, agar dilution method, checkerboard assay, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used for the assessment of anti-bacterial activity. Active ingredients screening, GO analysis, KEGG analysis, construction of PPI network, molecular docking, and RT-qPCR were used to elucidate the underlying pharmacological mechanisms of S. officinalis against H. pylori infection. Results The minimum inhibitory concentration (MIC) values of S. officinalis against multiple H. pylori strains including clinically isolated multi-drug resistant (MDR) strains were ranging from 160 to 320 µg/ml. These results showed that S. officinalis had additive interaction with four commonly used antibiotics and could exert antibacterial effect by changing the morphology of bacteria without developing drug resistance. Through network pharmacology analysis, 8 active ingredients in S. officinalis were screened out for subsequent studies. Among 222 putative targets of S. officinalis, 49 targets were identified as potential targets for treatment of H. pylori infection. And these 49 targets were significantly enriched in GO processes such as protein kinase B signaling, protein kinase activity, protein kinase binding, and KEGG pathways such as Pathways in cancer, MicroRNAs in cancer, and TNF signaling pathway. Protein-protein interaction analysis yielded 5 core targets (AKT1, VEGFA, EGFR, SRC, CCND1), which were validated by molecular docking and RT-qPCR. Conclusions Overall, this study confirmed the in vitro inhibitory activity of S. officinalis against H. pylori and explored the possible pharmacological mechanisms, laying the foundation for further research and clinical application.

Gate overshoot voltage prevention when driving E-mode GaN-based HEMTs is essential for system reliability and EMI suppression. Active gate drivers have been demonstrated to suppress gate voltage overshoot while maintaining fast turn-on. However, they normally require complex driving patterns that are determined using trial and error approaches. In this paper, an active gate driver with an integrated pattern generator is proposed to simplify the control of the dynamic gate driving strength pattern. For best trade-off between overshoot and transition speed, the gate resistance (or gate driving strength) must remain low but with a large resistance switched in briefly during the turn-on transition period. Switch timing of the driving pattern varies with load conditions and the types of transistor. To simplify the programming of the driving pattern, the gate driving strength can be controlled by changing only one external bias resistor in the proposed design. This in turn sets the bias current of a delay chain to adjust the timing of the gate driving strength pattern. The proposed design aims to create a systematic approach to simplify the selection of the gate driving strength pattern.

Jing-Jin Weng,* Jia-Zhang Wei,* Min Li, Shao-Jie Zhang, Yun-Zhong Wei, Han-Wei Wang, Dan-Xue Qin, Jin-Long Lu, He Jiang, Shen-Hong Qu Department of Otolaryngology & Head and Neck, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning 530021, People’s Republic of China*These authors contributed equally to this work.Correspondence: Shen-Hong QuDepartment of Otolaryngology & Head and Neck, The People’s Hospital of Guangxi Zhuang Autonomous Region, No. 6 Taoyuan Road, Nanning 530021, People’s Republic of ChinaTel +86-771-2186580Fax +86-771-2186317Email qshdoctor@163.comObjective: The efficacy of surgery as the primary treatment modality for nasopharyngeal carcinoma (NPC) is yet to be clarified. Therefore, we aimed to explore the short- and long-term efficacy of surgery for early-stage NPC.Methods: We retrospectively evaluated 341 patients diagnosed with early-stage NPC between September 2010 and December 2015. Among them, 58 patients underwent endoscopic nasopharyngectomy combined with chemoradiotherapy, whereas 283 patients underwent conventional chemoradiotherapy. The patients who underwent concurrent chemoradiotherapy or radiotherapy alone were matched to patients who underwent surgery in a 1:2 ratio using propensity score matching to analyze the clinical efficacy of each therapeutic modality. The primary endpoint was survival, and the secondary endpoints were tumor regression rate and reduction in Epstein–Barr virus (EBV)-DNA levels.Results: After matching, 156 patients were enrolled (58 patients in the surgery group; 98 patients in the non-surgery group). The baseline data of the matched patients had good inter-group comparability (All P> 0.05). The surgery group had significantly higher 5-year overall survival (98.30% vs. 91.70%), disease-free survival (98.30% vs. 81.40%), and recurrence-free survival (100.00% vs. 90.10%) rates than did the non-surgery group (All P< 0.05). In total, 0 and 14 patients in the surgery and non-surgery groups, respectively, had residual cancer at the end of treatment (P=0.001). All patients in the surgery group tested negative for EBV-DNA, whereas two patients in the non-surgery group tested positive. The incidence of hematologic toxicity during treatment was similar between the two groups (All P> 0.05). Still, the incidence of severe oral mucositis was lower in the surgery group than in the non-surgery group (37.9% vs. 54.08%, P=0.051).Conclusion: Surgery can improve the clearance rate of EB virus and reduce tumor residue. Surgery may be a safe and effective treatment for early NPC.Keywords: nasopharyngeal carcinoma, endoscopic surgery, radiotherapy, prognosis

International audience; Crassaminicella sp. strain SY095 is an anaerobic mesophilic marine bacterium that was recently isolated from a deep-sea hydrothermal vent on the Southwest Indian Ridge. Here, we present the complete genome sequence of strain SY095. The genome consists of a chromosome of 3,046,753 bp (G + C content of 30.81%) and a plasmid of 36,627 bp (G + C content of 31.29%), encodes 2966 protein, 135 tRNA genes, and 34 rRNA genes. Numerous genes are related to peptide transport, amino acid metabolism, motility, and sporulation. This agrees with the observation that strain SY095 is a spore-forming, motile, and chemoheterotrophic bacterium. Further, the genome harbors multiple prophages that carry all the genes necessary for viral particle synthesis. Some prophages carry additional genes that may be involved in the regulation of sporulation. This is the first reported genome of a bacterium from the genus Crassaminicella, providing insights into the microbial adaptation strategies to the deep-sea hydrothermal vent environment.

International audience; Marine environments are generally characterized by low bulk concentrations of nutrients that are susceptible to steady or intermittent motion driven by currents and local turbulence. Marine bacteria have therefore developed strategies, such as very fast-swimming and the exploitation of multiple directional sensing-response systems in order to efficiently migrate towards favorable places in nutrient gradients. The magnetotactic bacteria (MTB) even utilize Earth's magnetic field to facilitate downward swimming into the oxic-anoxic interface, which is the most favorable place for their persistence and proliferation, in chemically stratified sediments or water columns. To ensure the desired flagella-propelled motility, marine MTBs have evolved an exquisite flagellar apparatus, and an extremely high number (tens of thousands) of flagella can be found on a single entity, displaying a complex polar, axial, bounce, and photosensitive magnetotactic behavior. In this review, we describe gene clusters, the flagellar apparatus architecture, and the swimming behavior of marine unicellular and multicellular magnetotactic bacteria. The physiological significance and mechanisms that govern these motions are discussed.

Ethnopharmacological relevance Canarium album Raeusch. belongs to the Burseraceae family. Its ripe fruits, known as Qing Guo (QG) in Traditional Chinese Medicine (TCM), are used to treat sore throat, cough, and fish or crab poisoning. QG was reported to have antibacterial activity, and it exerted excellent anti-Helicobacter pylori (H. pylori) activity in our screening of abundant TCM. However, few studies have reported its anti-H. pylori activity and mechanism. Aim of study The commonly used eradication therapies for H. pylori infection are antibiotic-based therapies. With the increasing antibiotic resistance of H. pylori, interest in finding alternative therapies has been aroused. This study investigated the phytochemistry profile, in vitro anti-H. pylori activity and possible anti-bacterial mechanism of QG extracts. Materials and methods QG extracts were obtained by heat reflux extraction, ultrasonic extraction or liquid-liquid extraction with different solvents. The quantitative and qualitative phytochemical analyses were performed by colorimetric determination, high-performance liquid chromatography (HPLC), and UPLC-electrospray ionization mass spectrometry (ESI-MS). In vitro anti- H. pylori activity was assessed by broth micro-dilution method. Mechanism of action studies included morphological observation using electron microscopy, urease inhibition assay and determination of expression of virulence genes by RT-qPCR. Results All QG extracts especially ethyl acetate extract (QGEAE) were rich in phenolic components, with the minimum inhibitory concentrations (MICs) on H. pylori of 39–625 μg/ml and minimum bactericidal concentrations (MBCs) of 78–1250 μg/ml. Both aqueous extract (QGAE) and QGEAE could induce the morphological and structural changes of H. pylori, inhibit urease activity with IC50 of 1093 μg/ml and 332.90 μg/ml, respectively, and down-regulate the virulence genes, such as vacA and cagA. Conclusions QG may exhibit in vitro anti-H. pylori activity by inhibiting growth, destroying the bacterial structure and down-regulating the expression of virulence factors. Moreover, QG is the homology of food and TCM, which can be considered as a safe and convenient agent against H. pylori infection.

Magnetosome formation by Magnetospirillum gryphiswaldense MSR-1 is dependent on iron and oxygen levels. We used transcriptome to evaluate transcriptional profiles of magnetic and non-magnetic MSR-1 cells cultured under high-iron and low-iron conditions. A total of 80 differentially expressed genes (DEGs) were identified, including 53 upregulated and 27 downregulated under high-iron condition. These DEGs belonged to the functional categories of biological regulation, oxidation-reduction process, and ion binding and transport, and were involved in sulfur metabolism and cysteine/methionine metabolism. Comparison with our previous results from transcriptome data under oxygen-controlled conditions indicated that transcription of mam or mms was not regulated by oxygen or iron signals. 17 common DEGs in iron- and oxygen-transcriptomes were involved in energy production, iron transport, and iron metabolism. Some unknown-function DEGs participate in iron transport and metabolism, and some are potential biomarkers for identification of Magnetospirillum strains. IrrA and IrrB regulate iron transport in response to low-oxygen and high-iron signals, respectively. Six transcription factors were predicted to regulate DEGs. Fur and Crp particularly co-regulate DEGs in response to changes in iron or oxygen levels, in a proposed joint regulatory network of DEGs. Our findings provide new insights into biomineralization processes under high- vs. low-iron conditions in magnetotactic bacteria.

Magnetotactic multicellular prokaryotes (MMPs) consist of unique microorganisms formed by genetically identical Gram-negative bacterial that live as a single individual capable of producing magnetic nanoparticles called magnetosomes. Two distinct morphotypes of MMPs are known: spherical MMPs (sMMPs) and ellipsoidal MMPs (eMMPs). sMMPs have been extensively characterized, but less information exists for eMMPs. Here, we report the ultrastructure and organization as well as gene clusters responsible for magnetosome and flagella biosynthesis in the magnetite magnetosome producer eMMP Candidatus Magnetananas rongchenensis. Transmission electron microscopy and focused ion beam scanning electron microscopy (FIB-SEM) 3D reconstruction reveal that cells with a conspicuous core-periphery polarity were organized around a central space. Magnetosomes were organized in multiple chains aligned along the periphery of each cell. In the partially sequenced genome, magnetite-related mamAB gene and mad gene clusters were identified. Two cell morphologies were detected: irregular elliptical conical ` frustum-like' (IECF) cells and H-shaped cells. IECF cells merge to form H-shaped cells indicating a more complex structure and possibly a distinct evolutionary position of eMMPs when compared with sMMPs considering multicellularity.

Magnetotactic bacteria (MTB) are a group of phylogenetically and physiologically diverse Gram-negative bacteria that synthesize intracellular magnetic crystals named magnetosomes. MTB are affiliated with three classes of Proteobacteria phylum, Nitrospirae phylum, Omnitrophica phylum and probably with the candidate phylum Latescibacteria. The evolutionary origin and physiological diversity of MTB compared with other bacterial taxonomic groups remain to be illustrated. Here, we analysed the genome of the marine magneto-ovoid strain MO-1 and found that it is closely related to Magnetococcus marinus MC-1. Detailed analyses of the ribosomal proteins and whole proteomes of 390 genomes reveal that, among the Proteobacteria analysed, only MO-1 and MC-1 have coding sequences (CDSs) with a similarly high proportion of origins from Alphaproteobacteria, Betaproteobacteria, Deltaproteobacteria and Gammaproteobacteria. Interestingly, a comparative metabolic network analysis with anoxic network enzymes from sequenced MTB and non-MTB successfully allows the eventual prediction of an organism with a metabolic profile compatible for magnetosome production. Altogether, our genomic analysis reveals multiple origins of MO-1 and M. marinus MC-1 genomes and suggests a metabolism-restriction model for explaining whether a bacterium could become an MTB upon acquisition of magnetosome encoding genes.

Aloe vera has been widely used in cosmetics and as a health product. Although increasing research has indicated that chronic use of Aloe vera is closely associated with the development of colorectal cancer, the material basis and molecular mechanism of the pathogenesis have not been elucidated. The wnt/β-catenin signaling pathway plays an important role in the development of colorectal cancer. It should be useful to investigate whether Aloe vera has any impact on the wnt/β-catenin signaling pathway. In this study, we found that a water extract of Aloe vera at low concentration (0.98–12.50 μg ml−1) could activate the wnt/β-catenin signaling pathway in the presence of wnt3a ligand and up-regulated the level of active β-catenin protein in hek293 cells, as well as promoting the expression of wnt target genes (Axin2, DKK1, FGF20). Additionally, aloin and aloesin were the effective components interacting with other non-active ingredients in the water extract of Aloe vera that were identified by a knockout/knockin method with high-speed counter current chromatography (HSCCC). Meanwhile, no effects of the water extract of Aloe vera and aloin on the wnt/β-catenin signaling pathway were found, either in the presence or absence of other activators such as activator CHIR99021. In conclusion, the water extract of Aloe vera could activate the wnt/β-catenin signaling pathway in the presence of wnt3a and the effective components were aloin and aloesin. These findings might facilitate the understanding of the material basis and molecular mechanisms of Aloe vera in causing colorectal cancer.

The evolution of microbial magnetoreception (or magnetotaxis) is of great interest in the fields of microbiology, evolutionary biology, biophysics, geomicrobiology, and geochemistry. Current genomic data from magnetotactic bacteria (MTB), the only prokaryotes known to be capable of sensing the Earth’s geomagnetic field, suggests an ancient origin of magnetotaxis in the domain Bacteria. Vertical inheritance, followed by multiple independent magnetosome gene cluster loss, is considered to be one of the major forces that drove the evolution of magnetotaxis at or above the class or phylum level, although the evolutionary trajectories at lower taxonomic ranks (e.g., within the class level) remain largely unstudied. Here we report the isolation, cultivation, and sequencing of a novel magnetotactic spirillum belonging to the genus Terasakiella (Terasakiella sp. strain SH-1) within the class Alphaproteobacteria. The complete genome sequence of Terasakiella sp. strain SH-1 revealed an unexpected duplication event of magnetosome genes within the mamAB operon, a group of genes essential for magnetosome biomineralization and magnetotaxis. Intriguingly, further comparative genomic analysis suggests that the duplication of mamAB genes is a common feature in the genomes of alphaproteobacterial MTB. Taken together, with the additional finding that gene duplication appears to have also occurred in some magnetotactic members of the Deltaproteobacteria, our results indicate that gene duplication plays an important role in the evolution of magnetotaxis in the Alphaproteobacteria and perhaps the domain Bacteria. IMPORTANCE A diversity of organisms can sense the geomagnetic field for the purpose of navigation. Magnetotactic bacteria are the most primitive magnetism-sensing organisms known thus far and represent an excellent model system for the study of the origin, evolution, and mechanism of microbial magnetoreception (or magnetotaxis). The present study is the first report focused on magnetosome gene cluster duplication in the Alphaproteobacteria, which suggests the important role of gene duplication in the evolution of magnetotaxis in the Alphaproteobacteria and perhaps the domain Bacteria. A novel scenario for the evolution of magnetotaxis in the Alphaproteobacteria is proposed and may provide new insights into evolution of magnetoreception of higher species.

GaN power transistors are well suited in high frequency, high temperature and high power-density applications. This paper investigates different gate driver designs for GaN power transistors, including fundamental driving concerns, current commercial products, popular gate driving features, and design trends for the suppression of gate node ringing. Many smart gate drivers offer features such as intelligent on-chip CPU for flexible digital control, adjustable gate voltage levels, multi-stage driving speed for slew-rate control, precise timing control, current sensing capability for close-loop regulations, and active gate driving mode with continuous optimized dead-time. This paper provides an overview to modern gate driver design trends and challenges for GaN power transistors.

In an effort to understand the molecular events contributing to the cytotoxicity activity of resveratrol (RSV), we investigated its effects on human lung adenocarcinoma epithelial cell line A549 at different concentrations. Cellular nucleoside metabolic profiling was determined by an established liquid chromatography-mass spectrometry method in A549 cells. RSV resulted in significant decreases and imbalances of deoxyribonucleoside triphosphates (dNTPs) pools suppressing subsequent DNA synthesis. Meanwhile, RSV at high concentration caused significant cell cycle arrest at S phase, in which cells required the highest dNTPs supply than other phases for DNA replication. The inhibition of DNA synthesis thus blocked subsequent progression through S phase in A549 cells, which may partly contribute to the cytotoxicity effect of RSV. However, hydroxyurea (HU), an inhibitor of RNR activity, caused similar dNTPs perturbation but no S phase arrest, finally no cytotoxicity effect. Therefore, we believed that the dual effect of high concentration RSV, including S phase arrest and DNA synthesis inhibition, was required for its cytotoxicity effect on A549 cells. In summary, our results provided important clues to the molecular basis for the anticancer effect of RSV on epithelial cells.

Detection of reverse-conduction in GaN-based switched-mode power converters is essential to reduce power loss and to protect the circuit from severe undershoot voltage. In this paper, an active clamping SenseFET circuit is proposed to measure the duration that the low-side GaN HEMT is in reverse-conduction and with protection from the high voltage at the switching node. The output of the SenseFET clamping circuit is processed by a custom designed gate driver IC. This IC is fabricated using TSMC's $0.18\ \boldsymbol{\mu} \mathbf{m}$ BCD GEN2 process for driving e-mode GaN power HEMTs with an on-chip closed-loop dead-time correction circuit. The one-step correction mode can optimize the dead-times for both the turn-on and turn-off edges in one switching cycle for switching frequencies of up to 10 MHz with 0.32 ns precision. This allow the power converters to maintain optimal conversion efficiency over the full output current range.

Shewanella benthica DB21MT-2 is an obligate piezophilic bacterium isolated from the sediment of the Mariana Trench at depth of 10,898 m. Here we report the complete genome sequence of S. benthica DB21MT-2, which consists of a single circular chromosome with the size of 4,353,505 bp and G + C content of 45.86%. Comparative genomic analysis reveals the strain possesses multiple pathways for energy generation as has been reported in other deep-sea bacteria. In addition, several genes predicted to be involved in flagellar synthesis or component of toxin-antitoxin system are specifically found in obligate piezophilic strains from hadal trench. The result is expected to provide novel information for a better understanding on bacterial obligate piezophilic life-style and on bacterial adaptation to hadal trench environment.