Microbial community structures and in situ sulfate-reducing and sulfur-oxidizing activities in biofilms developed on mortar specimens in a corroded sewer system

Microbially induced concrete corrosion (MICC) caused by sulfuric acid attack in sewer systems has been a serious problem for a long time. A better understanding of microbial community structures of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) and their in situ activities is essential for the efficient control of MICC. In this study, the microbial community structures and the in situ hydrogen sulfide production and consumption rates within biofilms and corroded materials developed on mortar specimens placed in a corroded manhole was investigated by culture-independent 16S rRNA gene-based molecular techniques and microsensors for hydrogen sulfide, oxygen, pH and the oxidation-reduction potential. The dark-gray gel-like biofilm was developed in the bottom (from the bottom to 4 cm) and the middle (4 to 20 cm from the bottom of the manhole) parts of the mortar specimens. White filamentous biofilms covered the gel-like biofilm in the middle part. The mortar specimens placed in the upper part (30 cm above the bottom of the manhole) were corroded. The 16S rRNA gene-cloning analysis revealed that one clone retrieved from the bottom biofilm sample was related to an SRB, 12 clones and 6 clones retrieved from the middle biofilm and the corroded material samples, respectively, were related to SOB. In situ hybridization results showed that the SRB were detected throughout the bottom biofilm and filamentous SOB cells were mainly detected in the upper oxic layer of the middle biofilm. Microsensor measurements demonstrated that hydrogen sulfide was produced in and diffused out of the bottom biofilms. In contrast, in the middle biofilm the hydrogen sulfide produced in the deeper parts of the biofilm was oxidized in the upper filamentous biofilm. pH was around 3 in the corroded materials developed in the upper part of the mortar specimens. Therefore, it can be concluded that hydrogen sulfide provided from the bottom biofilms and the sludge settling tank was emitted to the sewer atmosphere, then oxidized to corrosive compounds in the upper and middle parts of the manhole, and only the upper part of the mortar specimens were corroded, because in the middle part of the manhole the generated corrosive compounds (e.g., sulfuric acid) was reduced in the deeper parts of the biofilm

Bipolar transverse thermopower and low thermal conductivity for an anomalous Nernst-type heat flux sensor in GdCo alloys

Abstract A Heat Flux Sensor (HFS) facilitates the visualization of heat flow, unlike a temperature sensor, and is anticipated to be a key technology in managing waste heat. Recently, an HFS utilizing the Anomalous Nernst Effect (ANE) has been proposed garnering significant interest in enhancing the transverse thermopower. However, ideal materials for HFS not only require a large transverse thermopower but also meet several criteria including low thermal conductivity and a bipolar nature of the transverse thermopower, especially a negative transverse thermopower. In this study, we have investigated ANE in amorphous ferrimagnetic GdCo alloys, revealing their numerous advantages as HFS materials. These include a large bipolar transverse thermopower, extremely low thermal conductivity, large negative sensitivity, versatility for deposition on various substrates, and a small longitudinal thermopower. These qualities position GdCo films as promising candidates for the advancement of HFS technology

Two Distinctive Binding Modes of Endonuclease Inhibitors to the N‑Terminal Region of Influenza Virus Polymerase Acidic Subunit

Influenza viruses are global threat to humans, and the development of new antiviral agents are still demanded to prepare for pandemics and to overcome the emerging resistance to the current drugs. Influenza polymerase acidic protein N-terminal domain (PA_N) has endonuclease activity and is one of the appropriate targets for novel antiviral agents. First, we performed X-ray cocrystal analysis on the complex structures of PA_N with two endonuclease inhibitors. The protein crystallization and the inhibitor soaking were done at pH 5.8. The binding modes of the two inhibitors were different from a common binding mode previously reported for the other influenza virus endonuclease inhibitors. We additionally clarified the complex structures of PA_N with the same two endonuclease inhibitors at pH 7.0. In one of the crystal structures, an additional inhibitor molecule, which chelated to the two metal ions in the active site, was observed. On the basis of the crystal structures at pH 7.0, we carried out 100 ns molecular dynamics (MD) simulations for both of the complexes. The analysis of simulation results suggested that the binding mode of each inhibitor to PA_N was stable in spite of the partial deviation of the simulation structure from the crystal one. Furthermore, crystal structure analysis and MD simulation were performed for PA_N in complex with an inhibitor, which was already reported to have a high compound potency for comparison. The findings on the presence of multiple binding sites at around the PA_N substrate-binding pocket will provide a hint for enhancing the binding affinity of inhibitors

Design, Synthesis, and Biological Evaluation of Novel 7‑[(3<i>aS</i>,7<i>aS</i>)‑3<i>a</i>‑Aminohexahydropyrano[3,4‑<i>c</i>]pyrrol-2(3<i>H</i>)‑yl]-8-methoxyquinolines with Potent Antibacterial Activity against Respiratory Pathogens

Novel 7-[(3<i>aS</i>,7<i>aS</i>)-3<i>a</i>-aminohexahydropyrano­[3,4-<i>c</i>]­pyrrol-2­(3<i>H</i>)-yl]-6-fluoro-1-[(1<i>R</i>,2<i>S</i>)-2- fluorocyclopropyl]-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid <b>5</b> (<b>DS21412020</b>) was designed and synthesized to obtain potent antibacterial drugs for the treatment of respiratory tract infections. Compound <b>5</b> possessing a <i>trans</i>-fused pyranose ring on the pyrrolidine moiety at the C-7 position of the quinolone scaffold exhibited potent in vitro antibacterial activity against respiratory pathogens, including quinolone-resistant and methicillin-resistant Staphylococcus aureus (QR-<i>MRSA</i>) and quinolone-resistant Escherichia coli (QR-E. coli). Furthermore, compound <b>5</b> showed in vivo activity against the experimental murine pneumonia model due to penicillin-resistant Streptococcus pneumoniae (<i>PRSP</i>) and favorable profiles in preliminary toxicological and nonclinical pharmacokinetic studies. In particular, the reduced lipophilicity and basicity of compound <b>5</b> as compared to those of the previously synthesized carba-type compound <b>4</b> resulted in a significant reduction in the human ether-a-go-go (hERG) related gene channel inhibition, which have the potential to prolong the QT interval

Design, Synthesis, and Biological Evaluation of Novel 7‑[(3<i>aS</i>,7<i>aS</i>)‑3<i>a</i>‑Aminohexahydropyrano[3,4‑<i>c</i>]pyrrol-2(3<i>H</i>)‑yl]-8-methoxyquinolines with Potent Antibacterial Activity against Respiratory Pathogens

Novel 7-[(3<i>aS</i>,7<i>aS</i>)-3<i>a</i>-aminohexahydropyrano­[3,4-<i>c</i>]­pyrrol-2­(3<i>H</i>)-yl]-6-fluoro-1-[(1<i>R</i>,2<i>S</i>)-2- fluorocyclopropyl]-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid <b>5</b> (<b>DS21412020</b>) was designed and synthesized to obtain potent antibacterial drugs for the treatment of respiratory tract infections. Compound <b>5</b> possessing a <i>trans</i>-fused pyranose ring on the pyrrolidine moiety at the C-7 position of the quinolone scaffold exhibited potent in vitro antibacterial activity against respiratory pathogens, including quinolone-resistant and methicillin-resistant Staphylococcus aureus (QR-<i>MRSA</i>) and quinolone-resistant Escherichia coli (QR-E. coli). Furthermore, compound <b>5</b> showed in vivo activity against the experimental murine pneumonia model due to penicillin-resistant Streptococcus pneumoniae (<i>PRSP</i>) and favorable profiles in preliminary toxicological and nonclinical pharmacokinetic studies. In particular, the reduced lipophilicity and basicity of compound <b>5</b> as compared to those of the previously synthesized carba-type compound <b>4</b> resulted in a significant reduction in the human ether-a-go-go (hERG) related gene channel inhibition, which have the potential to prolong the QT interval

Definition of Mucosal Breaks in the Era of Magnifying Endoscopy with Narrow-Band Imaging

Background. Gastroesophageal reflux disease is diagnosed endoscopically based on the presence of mucosal breaks. However, mucosal breaks can be judged differently depending on the endoscopist, even in the same image. We investigated how narrow-band imaging (NBI) and magnified endoscopy affect the judgment of mucosal breaks. Methods. A total of 43 consecutive patients were enrolled who had suspected mucosal breaks on white-light images (WLI) and underwent nonmagnified NBI (N-NBI) and magnified NBI (M-NBI) by a single endoscopist. From WLI, N-NBI, and M-NBI, 129 image files were created. Eight endoscopists reviewed the image files and judged the presence of mucosal breaks. Results. The 8 endoscopists determined mucosal breaks were present in 79.4 ± 9.5% (67.4%–93.0%) on WLI, and 76.7 ± 12.7% (53.5%–90.7%) on N-NBI. However, the percentage of mucosal breaks on M-NBI was significantly lower at 48.8 ± 17.0% (18.6%–65.1%) (p<0.05). Intraclass correlation between observers was 0.864 (95% CI 0.793–0.918) for WLI and 0.863 (95% CI 0.791–0.917) for N-NBI but was lower for M-NBI at 0.758 (95% CI 0.631–0.854). Conclusion. Rates of detection and agreement for mucosal breaks on WLI and N-NBI were high among endoscopists. However, these rates were lower on M-NBI

Clinicopathological Features of Advanced Gastric Cancers which Were Misjudged and Subjected to Endoscopic Submucosal Dissection

Background and Aims. Endoscopic submucosal dissection (ESD) is widely performed for early gastric cancer (EGC). We have sometimes encountered gastric cancer lesions for which ESD was performed and at which pathologically advanced cancer was found. In this study, we performed clinicopathological examination of lesions whose endoscopic diagnosis and pathology differed substantially. Methods. ESD was performed for 2,194 gastric cancer lesions (1,753 cases) in our institute from April 2005 through March 2015. The vertical margin was positive or status unknown in 51 lesions (2.3%); among these, muscularis propria (MP) or deeper infiltration was identified in 6 lesions from specimens obtained during subsequent surgery. In 1 lesion with MP invasion, the vertical margin was negative. We evaluated the clinicopathological features of these 7 lesions and retrospectively reviewed endoscopic indicators of submucosal invasion for EGC on white light imaging (WLI), narrow-band imaging magnifying endoscopy (NBI-ME), and endoscopic ultrasonography (EUS) performed previously. Results. Average age was 73.2±7.2 years, and all cases were men. The 7 lesions diagnosed as advanced cancer were 0.32% of 2,194 lesions and were all located in the U region (fundus). On retrospective review of endoscopic findings, 2 of 7 lesions on WBI, 3 of 6 lesions on NBI-ME, and 2 of 5 lesions on EUS met the criteria for indicating submucosal invasion of EGC. No lesions had findings on all 3 modalities. Conclusion. In rare cases, advanced gastric cancer could not be accurately diagnosed by endoscopy using various modalities. Each case had special characteristics making identification of deep infiltration difficult