Metagenomic insights into phenanthrene biodegradation in electrical field-governed biofilms for groundwater bioremediation.

Electrical fields (EFs)-assisted in-situ bioremediation of petroleum-contaminated groundwater, such as polycyclic aromatic hydrocarbons, has drawn increasing attention. However, the long-term stability, the EFs influence, and metabolic pathways are still poorly understood, hindering the further development of robust technology design. Herein, a series of EFs was applied to the phenanthrene-contaminated groundwater, and the corresponding system performance was investigated. The highest removal capacity of phenanthrene (phe) (7.63 g/(m3·d)) was achieved with EF_0.8 V biofilm at a hydrolytic retention time of 0.5 d. All the biofilms with four EFs exhibited a high removal efficiency of phe over 80% during a 100-d continuous-flow operation. Intermediates analysis revealed the main pathways of phe degradation: phthalate and salicylate via hydroxylation, methylation, carboxylation, and ring cleavage steps. Synergistic effects between phe-degraders (Dechloromonas), fermentative bacteria (Delftia), and electroactive microorganisms (Geobacter) were the main contributors to the complete phe mineralization. Genes encoding various proteins of methyl-accepting (mcp), response regulator (cheABDRY), and type IV pilus (pilABCMQV) were dominant, revealing the importance of cell motility and extracellular electron transfer. Metagenomics analysis unveiled phe-degrading genes, including ring reduction enzymes (bamBCDE), carboxylase of aromatics (ubiD), and methyltransferase protein (ubiE, pcm). These findings offered a molecular understanding of refractory organics' decompositions in EFs-governed biotechnology.

Preparation of graphitized carbon by the corn straw liquefaction method.

Corn straw-based graphitized carbon was prepared by carbonization and a catalyzed graphitization method using corn straw as the raw material and catalytic liquefaction technology. A mixture of polyethylene glycol (PEG200) compounded with glycerol in the mass ratio of 7 : 3 was used as the liquefied agent, meanwhile 0.3 g of hydroxydiethylidene glycolic acid acted as the liquefied catalyst. The liquefied products were treated via carbonization and graphitization processes to form graphitized carbon. The graphitized carbon showed better graphitization, a microscopic lamellar structure, and smaller defects, when the carbonized temperature was 600 °C, graphitization temperature 850 °C, and the catalyst was ferric acetylacetonate at a concentration of 7.0 mmol g-1. The corn straw-based graphitized carbon yield reached 22.20%.

Pulmonary-function changes after uniportal video-assisted thoracoscopic anatomical lung resection.

OBJECTIVE: The superiority of segmentectomy over lobectomy with regard to preservation of pulmonary function is controversial. This study aimed to examine changes in pulmonary function after uniportal video-assisted thoracoscopic surgery (VATS) according to the number of resected segments. METHODS: We retrospectively reviewed 135 consecutive patients who underwent anatomical lung resection via uniportal VATS from April 2015 to December 2020. Pulmonary function loss was evaluated using forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). Patients were grouped according to number of resected segments: one-segment (n = 33), two segments (n = 22), three segments (n = 40), four segments (n = 15), and five segments (n = 25). RESULTS: Clinical characteristics did not significantly differ between groups, except for tumor size. Mean follow-up was 8.96 ± 3.16 months. FVC loss was significantly greater in five-segment resection (10.8%) than one-segment (0.97%, p = 0.008) and two-segment resections (2.44%, p = 0.040). FEV1 loss was significantly greater in five-segment resection (15.02%) than one-segment (3.83%, p < 0.001), two-segment (4.63%, p = 0.001), and three-segment resections (7.63%, p = 0.007). Mean FVC loss and FEV1 loss increased linearly from one-segment resection to five-segment resection. Mean loss in FVC and FEV1 per segment resected was 2.16% and 3.00%, respectively. CONCLUSIONS: Anatomical lung resection of fewer segments was associated with better preservation of pulmonary function in patients undergoing uniportal VATS, and function loss was approximately 2%-3% per segment resected with linear relationship.

Three-stage approach for aortoesophageal fistula after Roux-en-Y esophagojejunostomy.

Surgical management of post-esophagojejunostomy aortoesophageal fistula (AEF) has been scarcely reported, but is universally fatal. This report described a case of AEF after total gastrectomy with Roux-en-Y esophagojejunostomy and adjuvant chemoradiotherapy for gastric cardiac cancer. A three-stage hybrid approach was used to successfully manage this complication. First, thoracic endovascular aortic repair curbed bleeding. Second, radical fistula resection eradicated infected areas and adjacent structures. Third, esophageal reconstruction using an ileocolonic conduit restored gastrointestinal continuity. This strategy could be safely feasible for managing post-esophagojejunostomy AEF.

Compressed Sensing Photoacoustic Imaging Reconstruction Using Elastic Net Approach.

Photoacoustic imaging involves reconstructing an estimation of the absorbed energy density distribution from measured ultrasound data. The reconstruction task based on incomplete and noisy experimental data is usually an ill-posed problem that requires regularization to obtain meaningful solutions. The purpose of the work is to propose an elastic network (EN) model to improve the quality of reconstructed photoacoustic images. To evaluate the performance of the proposed method, a series of numerical simulations and tissue-mimicking phantom experiments are performed. The experiment results indicate that, compared with the L 1-norm and L 2-normbased regularization methods with different numerical phantoms, Gaussian noise of 10-50 dB, and different regularization parameters, the EN method with α = 0.5 has better image quality, calculation speed, and antinoise ability.

Synthesis of Core-Shell Magnetic Fe3O4@poly(m-Phenylenediamine) Particles for Chromium Reduction and Adsorption.

Magnetic Fe3O4@poly(m-phenylenediamine) particles (Fe3O4@PmPDs) with well-defined core-shell structure were first designed for high performance Cr(VI) removal by taking advantages of the easy separation property of magnetic nanoparticles (MNPs) and the satisfactory adsorption property of polymers. Through controlling the polymerization on MNPs, directly coating was realized without the complicated premodification procedures. The particle property and adsorption mechanism were analyzed in details. Fe3O4@PmPDs exhibited tunable PmPD shell thickness from 10 to 100 nm, high magnetic (∼150 to ∼73 emu g(-1)) and facile separation property by magnet. The coating of PmPD significantly enhanced Cr(VI) adsorption capacity from 46.79 (bare MNPs) to 246.09 mg g(-1) (71.55% PmPD loading proportion), much higher than many reported composite adsorbents. The high Cr(VI) removal performance was attributed to the adsorption of Cr(VI) on protonated imino groups and the efficient reduction of Cr(VI) to Cr(III) by amine, followed by Cr(III) chelated on imino groups, which are spontaneous and endothermic. The Fe3O4@PmPDs have great potential in treating Cr(VI)-contaminated water.

Structure and stability of an azoreductase with an FAD cofactor from the strict anaerobe Clostridium perfringens.

Azoreductase enzymes present in many microorganisms exhibit the ability to reduce azo dyes, an abundant industrial pollutant, to produce carcinogenic metabolites that threaten human health. All biochemically-characterized azoreductases, around 30 to date, have been isolated from aerobic bacteria, except for AzoC, the azoreductase of Clostridium perfringens, which is from a strictly anaerobic bacterium. AzoC is a recently biochemically-characterized azoreductase. The lack of structural information on AzoC hinders the mechanistic understanding of this enzyme. In this paper, we report on the biophysical characterization of the structure and thermal stability of AzoC by using a wide range of biophysical tools: Liquid Chromatography-Mass Spectrometry (LC-MS), Circular Dichroism Spectroscopy, Fourier-transform Infrared (FTIR) Spectroscopy, SDS-PAGE, Size Exclusion Chromatography, MALDI-TOF and UV-visible spectroscopy. We found that the flavin cofactor of AzoC is FAD, while all other structurally-known azoreductases employ FMN as a cofactor. The secondary structure of AzoC has 16% less α-helix structures, 5% more ß-sheet structures and 11% more turn and unordered than the average of structurally-known azoreductase that have 10-14% sequence similarities with AzoC. We also found that oxidized AzoC is trimeric, which is unique amongst structurally known azoreductases. In contrast, reduced AzoC is monomeric, despite similarities in catalytic activity and thermal stability of oxidized and reduced AzoC. Our results show that the use of FTIR spectroscopy is crucial for characterization of the ß-sheet content in AzoC, illustrating the need for complementary biophysical tools for secondary structural characterization of proteins.

Controllable synthesis of hierarchical porous Fe3O4 particles mediated by poly(diallyldimethylammonium chloride) and their application in arsenic removal.

Hierarchical porous Fe3O4 particles with tunable grain size were synthesized based on a facile poly (diallyldimethylammonium chloride) (PDDA)-modulated solvothermal method. The products were characterized with scanning electron microscopy (SEM) and transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), N2 adsorption-desorption technique, vibrating sample magnetometer (VSM), and dynamic light scattering (DLS). The results show that increasing the PDDA dosage decrease the grain size and particle size, which increased the particle porosity and enhanced the surface area from 7.05 to 32.75 m(2) g(-1). Possible mechanism can be ascribed to the PDDA function on capping the crystal surface and promoting the viscosity of reaction medium to mediate the growth and assembly of grain. Furthermore, the arsenic adsorption application of the as-obtained Fe3O4 samples was investigated and the adsorption mechanism was proposed. High magnetic Fe3O4 particles with increased surface area display improved arsenic adsorption performance, superior efficiency in low-level arsenic removal, high desorption efficiency, and satisfactory magnetic recyclability, which are very promising compared with commercial Fe3O4 particles.

Development of three Drosophila melanogaster strains with different sensitivity to volatile anesthetics.

BACKGROUND: The mechanisms of action for volatile anesthetics remain unknown for centuries partly owing to the insufficient or ineffective research models. We designed this study to develop three strains derived from a wild-type Drosophila melanogaster with different sensitivities to volatile anesthetics, which may ultimately facilitate molecular and genetic studies of the mechanism involved. METHODS: Median effective doses (ED(50)) of sevoflurane in seven-day-old virgin female and male wild-type Drosophila melanogaster were determined. The sensitive males and females of percentile 6 - 10 were cultured for breeding sensitive offspring (S(1)). So did median ones of percentile 48 - 52 for breeding median offspring (M(1)), resistant ones of percentile 91 - 95 for breeding resistant offspring (R(1)). Process was repeated through 31 generations, in the 37th generation, S(37), M(37) and R(37) were used to determine ED(50) for enflurane, isoflurane, sevoflurane, desflurane, halothane, methoxyflurane, chloroform and trichloroethylene, then ED(50) values were correlated with minimum alveolar concentration (MAC) values in human. RESULTS: From a wild-type Drosophila melanogaster we were able to breed three strains with high, median and low sevoflurane requirements. The ratio of sevoflurane requirements of three strains were 1.20:1.00:0.53 for females and 1.22:1.00:0.72 for males. Strains sensitive, median and resistant to sevoflurane were also sensitive, median and resistant to other volatile anesthetics. For eight anesthetics, ED(50) values in three strains correlated directly with MAC values in human. CONCLUSIONS: Three Drosophila melanogaster strains with high, median and low sensitivity to volatile anesthetics, but with same hereditary background were developed. The ED(50) are directly correlated with MAC in human for eight volatile anesthetics.