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GSK3335065 is an inhibitor of kynurenine monooxygenase (KMO) being developed for the treatment of acute pancreatitis. Healthy male volunteers were administered ascending doses of GSK3335065 or matched placebo as a single intravenous bolus injection to assess safety, tolerability, pharmacokinetics and pharmacodynamics. GSK3335065 displayed an apparent volume of distribution between 20.6 L and 44.6 L, a clearance between 0.462 L/h and 0.805 L/hr and a terminal half-life between 31.3 and 34.5 hr. In the single subject who received 1.3 mg GSK3335065, changes in tryptophan pathway metabolites were observed consistent with the changes seen in preclinical species suggesting that KMO enzyme activity was partially inhibited. However, a broad complex ventricular tachycardia was observed in this subject, which was judged to be a Serious Adverse Event (SAE) and resulted in early termination of the study. While development of GSK3335065 was subsequently discontinued, significant confounding factors hinder a clear interpretation that the tachycardia was directly related to administration of the compound.

The storage of dynamic information in hydrogel is extremely interesting due to the reprogrammable and responsive features of hydrogel. Here, we report that structural information can be stored in polysaccharide hydrogel by electrically induced covalent cross-linking, and the imbedded information can be retrieved by different means (dye adsorption, protonation of chitosan, and acid dissolution). Taking the advantage of diffusible feature of hydrogel, OH- was generated from the contacting area of the electrode and controllably diffused by electrical writing, thus the high pH domain (pH ∼ 10) triggered covalent cross-linking of the hydrogel. The written area exhibits different micromorphology, chemical properties, and pH sensitivity, allowing dynamic 2D and 3D information to be stored and read when necessary. This work demonstrates the use of stable electrical inputs to store dynamic structural information in a biopolymer-based hydrogel and how the chemical and physical varies allow eye recognition to the embedded information.

The interaction between cucurbit[7]uril (Q[7]) and a series of 4-pyrrolidinopyridinium salts bearing aliphatic substituents at the pyridinium nitrogen, namely 4-(C4H8N)C5H5NRBr, where R = H (C0), Et (C2), n-butyl (C4), n-hexyl (C6), has been studied in aqueous solution by 1H NMR spectroscopy, electronic absorption spectroscopy, and mass spectrometry.

Florfenicol is widely used to control respiratory diseases and intestinal infections in food animals. However, there are increasing reports about florfenicol resistance of various clinical pathogens. floR is a key resistance gene that mediates resistance to florfenicol and could spread among different bacteria. Here, we investigated the prevalence of floR in 430 Pseudomonas aeruginosa isolates from human clinical samples and identified three types of floR genes (designated floR, floR-T1 and floR-T2) in these isolates, with floR-T1 the most prevalent (5.3%, 23/430). FloR-T2 was a novel floR variant identified in this study, and exhibited less identity with other FloR proteins than FloRv. Moreover, floR-T1 and floR-T2 identified in P. aeruginosa strain TL1285 were functionally active and located on multi-drug resistance region of a novel incomplete Tn4371-like integrative and conjugative elements (ICE) in the chromosome. The expression of the two floR variants could be induced by florfenicol or chloramphenicol. These results indicated that the two floR variants played an essential role in the host’s resistance to amphenicol and the spreading of these floR variants might be related with the Tn4371 family ICE.

BackgroundChildren with severe acute malnutrition (SAM) have inadequate levels of fatty acids (FAs) and limited capacity for enteral nutritional rehabilitation. We hypothesized that topical high-linoleate sunflower seed oil (SSO) would be effective adjunctive treatment for children with SAM.MethodsThis study tested a prespecified secondary endpoint of a randomized, controlled, unblinded clinical trial with 212 children with SAM aged 2 to 24 months in two strata (2 to ResultsEmollient therapy led to systematically higher increases in 26 of 29 FAs over time compared to the control. These effects were driven primarily by changes in younger subjects (27 of 29 FAs). Several FAs, especially those most abundant in SSO showed high-magnitude but non-significant incremental increases from day 0 to day 10 in the emollient group vs. the no-emollient group; for linoleic acid, a 237 μg/mL increase was attributable to enteral feeding and an incremental 98μg/mL increase (41%) was due to emollient therapy. Behenic acid (22:0), gamma-linolenic acid (18:3n6), and eicosapentaenoic acid (20:5n3) were significantly increased in the younger age stratum; minimal changes were seen in the older children.ConclusionsSSO therapy for SAM augmented the impact of enteral feeding in increasing levels of several FAs in young children. Further research is warranted into optimizing this novel approach for nutritional rehabilitation of children with SAM, especially those Trial registrationClinicalTrials.gov:NCT02616289.

Graphical abstract, Cell-based therapies have shown significant promise in tissue engineering with one key challenge being the delivery and retention of cells. As a result, significant efforts have been made in the past decade to design injectable biomaterials to host and deliver cells at injury sites. Intervertebral disc (IVD) degeneration, a major cause of back pain, is a particularly relevant example where a minimally-invasive cellular therapy could bring significant benefits specifically at the early stages of the disease, when a cell-driven process starts in the gelatinous core of the IVD, the nucleus pulposus (NP). In this present study we explore the use of graphene oxide (GO) as nano-filler for the reinforcement of FEFKFEFK (β-sheet forming self-assembling peptide) hydrogels. Our results confirm the presence of strong interactions between FEFKFEFK and GO flakes with the peptide coating and forming short thin fibrils on the surface of the flakes. These strong interactions were found to affect the bulk properties of hybrid hydrogels. At pH 4 electrostatic interactions between the peptide fibres and the peptide-coated GO flakes are thought to govern the final bulk properties of the hydrogels while at pH 7, after conditioning with cell culture media, electrostatic interactions are removed leaving the hydrophobic interactions to govern hydrogel final properties. The GO-F820 hybrid hydrogel, with mechanical properties similar to the NP, was shown to promote high cell viability and retained cell metabolic activity in 3D over the 7 days of culture and therefore shown to harbour significant potential as an injectable hydrogel scaffold for the in-vivo delivery of NP cells. Statement of Significance Short self-assembling peptide hydrogels (SAPHs) have attracted significant interest in recent years as they can mimic the natural extra-cellular matrix, holding significant promise for the ab initio design of cells’ microenvironments. Recently the design of hybrid hydrogels for biomedical applications has been explored through the incorporation of specific nanofillers. In this study we exploited graphene oxide (GO) as nanofiller to design hybrid injectable 3Dscaffolds for the delivery of nucleus pulposus cells (NPCs) for intervertebral disc regeneration. Our work clearly shows the presence of strong interactions between peptide and GO, mimicking the mechanical properties of the NP tissue and promoting high cell viability and metabolic activity. These hybrid hydrogels therefore harbour significant potential as injectable scaffolds for the in vivo delivery of NPCs.

The development of physical approaches and green technologies to construct novel chitin materials is essential for the exquisite utilization of the renewable and valuable resource of chitin. In the present study, chitin nanogels were simply fabricated from a chitin solution dissolved in 8% NaOH/4% urea aqueous solvent by high speed stirring. The mechanical stirring generated in situ heat that induced the regeneration of chitin chains and ensured good dispersion of the nanogels. The prepared nanogels were composed of spherical nanoparticles of size 20 to 30 nm with some aggregates. The formation of chitin nanogels was confirmed to be a physical process without using organic solvent or chemical crosslinking. Rheological tests revealed a shear thinning behavior of the nanogels and injectable hydrogels were developed accordingly. The chitin nanogels showed no toxicity to L929 cells and cell attachment on the surface of the nanogel was observed. Further, monodispersed cationic nanogels and anionic nanogels were facilely obtained by deacetylating and TEMPO-mediated oxidizing chitin nanogels, and demonstrated different antibacterial properties.

Excessive bleeding due to trauma, surgery and diseases may cause severe mortalities. Here, an emerging chitin nanogel/rectorite nanocomposite is developed for effective hemorrhage control. Chitin chains are intercalated into rectorite and subsequent mechanical high speed stirring generates chitin nanogels, which assemble on the surface of the rectorite nanoplates through electrostatic interactions to form a sandwich structure. The in vitro experiments reveal that the nanocomposite exhibits favorable biocompatibility and negligible hemolysis (

Perovskite solar cells (PSCs) have attracted enormous attention because of their superior photovoltaic conversion efficiency and low-cost solution processibility. Electron transport layer (ETL) is essential to the performance of PSCs due to its ability of transporting electrons and blocking holes. Herein, the effect of different Ti precursors, tetrabutyl titanate (TT) and titanium diisopropoxide bis (acetylacetonate) (TDB), on the properties of derived TiO2 ETL was systematically investigated. It is noted that the change of Ti precursor have significant influence on the surface state and morphology, electron extraction ability and interface recombination resistance, but not on the crystal phases and chemical states of the obtained TiO2 ETLs. Moreover, compared with TiO2 ETL derived from TDB, the one obtained from TT displays the superior photoelectric properties and the PSCs based on this ETL acquire the best power conversion efficiency (PCE) of 17.4% with an open-circuit voltage (Voc) of 1.1 V, a short-circuit current density (Jsc) of 23.2 mA cm−2 and a fill factor (FF) of 68%. We believe that some fundamental insight into the impact of Ti precursor was provided in this research, aiming to find the criterion of the qualified ETL and paving the route for fabricating desirable ETL.

There is extensive debate about how 2D nanomaterials such as graphene oxide (GO) affect bacteria. Various effects of GO are proposed, including bacterial growth inhibition or enhancement, killing, and no activity. Herein, we report that GO protects Staphylococcus aureus bacterial cells from death in starvation conditions with up to a 1000-fold improvement in cell viability. Transcriptomic profiling reveals that bacterial cells in starvation conditions generally shut down metabolic activity, while only cells incubated with GO increase production of specific enzymes involved in the glyoxalase detoxification pathway along with repressed autolysis. The oxygen-containing functional groups of GO resemble the molecular structure of methylglyoxal, which bacteria produce to adapt to nutrient imbalances and is detoxified by glyoxalase enzymes. The ability of GO to enable bacterial cell survival in starvation conditions and accompanying cellular responses support that bacterial cells perceive GO as a methylglyoxal-mimicking nanomaterial cue to reshuffle cellular metabolism and defenses. National Research Foundation (NRF) This work was supported by the National Research Foundation of Singapore through a Competitive Research Programme grant (NRF-CRP10-2012-07) and a Proof-of-Concept grant (NRF2015NRF-POC0001-19), the National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (No. 2020R1C1C1004385), and the Ministry of Education, Youth and Sports grant LL2002 under the ERC CZ program. In addition, this work was supported by the Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2019H1D3A1A01070318).

Herein we present a simple fluorescence quenching method to selectively recognise and determine L-tryptophan (L-Trp) out of other 19 natural amino acids. Methylpillar[5]arene (MeP5), which is employed as a macrocyclic fluorescent probe, exhibits fluorescence activity in the solution of poor solvents because of aggregation-induced emission (AIE) effect. Fluorescence quenching of MeP5 in the solution of EtOH/CH2Cl2 (98/2, v/v) was observed upon the addition of L-Trp whereas other 19 natural amino acids did not bring about obvious change in fluorescence intensity. 1H NMR titration, fluorescence spectroscopy, mass spectrometry and theoretical analysis revealed that L-Trp can be encapsulated into the cavity of MeP5 to form a stable 1:1 host–guest inclusion complex which accounts for the quenching characteristics. The proposed procedure in this investigation offers an attractive and promising method for the selective detection of L-Trp in a mixture of natural amino acids.

Yokenella regensburgei, a member of the family Enterobacteriaceae, is usually isolated from environmental samples and generally resistant to early generations of cephalosporins. To characterize the resistance mechanism of Y. regensburgei strain W13 isolated from the sewage of an animal farm, whole genome sequencing, comparative genomics analysis and molecular cloning were performed. The results showed that a novel chromosomally encoded class C β-lactamase gene with the ability to confer resistance to β-lactam antibiotics, designated bla YOC - 1, was identified in the genome of Y. regensburgei W13. Kinetic analysis revealed that the β-lactamase YOC-1 has a broad spectrum of substrates, including penicillins, cefazolin, cefoxitin and cefotaxime. The two functionally characterized β-lactamases with the highest amino acid identities to YOC-1 were CDA-1 (71.69%) and CMY-2 (70.65%). The genetic context of the bla YOC - 1 -ampR-encoding region was unique compared with the sequences in the NCBI nucleotide database. The plasmid pRYW13-125 of Y. regensburgei W13 harbored 11 resistance genes (bla OXA - 10, bla LAP - 2, dfrA14, tetA, tetR, cmlA5, floR, sul2, ant(3″)-IIa, arr-2 and qnrS1) within an ∼34 kb multidrug resistance region; these genes were all related to mobile genetic elements. The multidrug resistance region of pYRW13-125 shared the highest identities with those of two plasmids from clinical Klebsiella pneumoniae isolates, indicating the possibility of horizontal transfer of these resistance genes between bacteria of various origins.

The ability to pattern and actuate hydrogels is essential for biomimetics, soft robotics, and biosensors. Here an electrical writing technique with the capability to create both surface and across thickness patterns in dynamic chitosan-H+ /agarose hydrogel by electronically generated pH gradient is introduced. The diffusible pH cues deprotonate and re-assemble chitosan chains by hydrogen bonds, changing the electrical writing domains from original loose structure to a dense layer and resulting in different mechanical stress and swell ability that causes the hydrogel to deform. The deformable trend can be modulated by writing depth and selective writing area on the surface, and significantly enhanced by temperature increment. Finally, a dual electrical writing process to create three-dimensional patterns and demonstrate programmable shape transition by differing patterns is performed.

Conjugated oligoelectrolytes (COEs) are emerging antimicrobials with broad spectrum activity against Gram positive and Gram negative bacteria as well as fungi. Our previous in vitro evolution studies using Enterococcus faecalis grown in the presence of two related COEs (COE1-3C and COE1-3Py) led to the emergence of mutants (changes in liaF and liaR) with a moderate 4- to16-fold increased resistance to COEs. The contribution of liaF and liaR mutations to COE resistance was confirmed by complementation of the mutants, which restored sensitivity to COEs. To better understand the cellular target of COEs, and the mechanism of resistance to COEs, transcriptional changes associated with resistance in the evolved mutants were investigated in this study. The differentially transcribed genes encoded membrane transporters, in addition to proteins associated with cell envelope synthesis and stress responses. Genes encoding membrane transport proteins from the ATP binding cassette superfamily were the most significantly induced or repressed in COE tolerant mutants compared to the wild type when exposed to COEs. Additionally, differences in the membrane localization of a lipophilic dye in E. faecalis exposed to COEs suggested that resistance was associated with lipid rearrangement in the cell membrane. The membrane adaptation to COEs in EFC3C and EFC3Py resulted in an improved tolerance to bile salt and sodium chloride stress. Overall, this study showed that bacterial cell membranes are the primary target of COEs and that E. faecalis adapts to membrane interacting COE molecules by both lipid rearrangement and changes in membrane transporter activity. The level of resistance to COEs suggests that E. faecalis does not have a specific response pathway to elicit resistance against these molecules and this is supported by the rather broad and diverse suite of genes that are induced upon COE exposure as well as cross-resistance to membrane perturbing stressors. Ministry of Education (MOE) Ministry of Health (MOH) National Medical Research Council (NMRC) National Research Foundation (NRF) Published version This research was also supported by the Singapore Ministry of Education Tier 3 Grant (MOE2013-T3-1-002) and by the Singapore Ministry of Education Tier 2 Grant (M4360005.C70). AM was supported by a Singapore Ministry of Health Grant, NMRC/CBRG/0086/2015, awarded to KK. Work at UCSB has been supported through supported by the Institute for Collaborative Biotechnologies through grant W911NF-09-0001 from the U.S. Army Research Office. Further financial support was provided from the Singapore Centre for Environmental Life Sciences Engineering (SCELSE), whose research was supported by the National Research Foundation Singapore and Ministry of Education under its Research Centre of Excellence Programme.

Inspired by the gradient hygroscopic structure of carrotwood seed pod, patterned anisotropic structure was created in polysaccharide hydrogel by an anodic electrical writing process. Locally released Fe2+ was oxidized to Fe3+ and chelated with chitosan chains in the written area, resulting in a gradient structure in the hydrogel. The asymmetrical stress generated by the different swelling of the gradient structure enables the hydrogel to bend autonomously. The hydrogel shows opposite bending in deionized water and NaCl solution. The physicochemical properties of the hydrogel are characterized by tensile test, SEM, EDS, XRD, TGA, DTG and FT-IR. SEM and EDS show that the written hydrogel has a structural gradient and a concentration gradient of Fe3+ vertically. Moreover, anodic electrical writing increases the flexibility of chitosan hydrogel due to decreased crystallinity. This controllable electrical writing technique is convenient to create patterned anisotropic structure and provide a novel design concept for natural hydrogel actuators.

Perovskite solar cells (PSCs) with inverted planar heterojunction (p-i-n) structure have attracted wide attention due to their facile preparation and flexible application. So far, poly(bis{4-phenyl}{2,4,6-trimethylphenyl}amine) (PTAA) as the hole-transport material has promised the state-of-the-art performance for p-i-n PSCs. However, the hydrophobic nature of PTAA has two contradictory impacts on the PSCs performance, namely the perfect resistance of corrosion and hygroscopicity versus the large surface-tension and incomplete surface coverage of the photoactive perovskite film. To address this challenge, an inorganic potassium fluoride (KF) buffer layer was introduced onto the PTAA substrate to regulate the surface-energy difference between PTAA and the perovskite precursor. As a result, superb quality perovskite film was synthesized. In addition, the KF treatment also downward shifts the valence-band maximum (VBM) of the polymer toward the VBM of perovskite thus facilitating the hole extraction from the perovskite to PTAA and in turn enlarging both the short-circuit current density (JSC) and open-circuit voltage (VOC) Therewith, the planar inverted perovskite solar cell aided by KF realizes a champion power conversion efficiency (PCE) of 21.51% with a JSC of 23.95 mA/cm2, VOC of 1.09V, and fill factor of 82.4%. It is also important that optimized devices exhibit excellent long-term stability, with 90% of the original PCE retained after 30 days under ambient conditions (60% humidity).

A substantial body of evidence suggests the existence of MUC1-specific antibodies and cytotoxic T cell activities in pancreatic cancer patients. However, tumor-induced immunosuppression renders these responses ineffective. The current study explores a novel therapeutic combination wherein tumor-bearing hosts can be immunologically primed with their own antigen, through opsonization with a tumor antigen-targeted antibody, mAb-AR20.5. We evaluated the efficacy of immunization with this antibody in combination with PolyICLC and anti-PD-L1. The therapeutic combination of mAb-AR20.5 + anti-PD-L1 + PolyICLC induced rejection of human MUC1 expressing tumors and provided a long-lasting, MUC1-specific cellular immune response, which could be adoptively transferred and shown to provide protection against tumor challenge in human MUC1 transgenic (MUC.Tg) mice. Furthermore, antibody depletion studies revealed that CD8 cells were effectors for the MUC1-specific immune response generated by the mAb-AR20.5 + anti-PD-L1 + PolyICLC combination. Multichromatic flow cytometry data analysis demonstrated a significant increase over time in circulating, activated CD8 T cells, CD3+CD4-CD8-(DN) T cells, and mature dendritic cells in mAb-AR20.5 + anti-PD-L1 + PolyICLC combination-treated, tumor-bearing mice, as compared to saline-treated control counterparts. Our study provides a proof of principle that an effective and long-lasting anti-tumor cellular immunity can be achieved in pancreatic tumor-bearing hosts against their own antigen (MUC1), which can be further potentiated using a vaccine adjuvant and an immune checkpoint inhibitor.

The accelerated microbial resistance evoked by the misuse and improper disposal of antibiotics has posed severe thereat to the public health. Despite considerable efforts on antimicrobial materials development, it is demanding to search for safe and effective antibacterial agents capable of minimizing resistance risks. Here, zinc oxide nanoparticles (ZnO NPs) integrated superparamagnetic iron oxide (SPIO/ZnO NPs) as recyclable bactericide was formed through the one-pot synthesis strategy. The obtained SPIO/ZnO NPs of desirable biocompatibility efficiently inhibit S. aureus and E. coli growth, of which the bactericidal activities were retained for four cycles of repeated use. Furthermore, the mechanistic studies of antibiosis revealed the damaging role of the nanocomposite to the bacteria cells through a tight attachment on the cell membrane, followed by the regulated release of Zn2+ from the composites. The produced recyclable SPIO/ZnO NPs of negligible development of bacterial resistance hold potentials for practical applications.

Simple Summary Macrophage polarization-associated extracellular vesicles (EVs) play crucial roles in tumor progression. The role of miR-21-5p in EVs during esophageal squamous cell carcinoma (ESCC) development must be clarified. This study aimed to identify the relationship between ESCC cells and macrophages in different polarization states during the delivery of EVs-miR-21-5p. We found that M0 macrophages took up overexpressed EVs-miR-21-5p secreted by EC109 or EC9706 cells, which transformed them into M2 macrophages through the PTEN/AKT/STAT6 pathway. This, in turn, contributed to secretion of high levels of TGF-β1 by M2 macrophages and promoted esophageal cancer cell epithelial-mesenchymal transition via the TGF-β/Smad2 axis. These findings indicate that EVs-miR-21-5p may be a critical molecule for ESCC. Abstract The disorganized polarization of tumor-associated macrophages (TAMs) exerts a critical effect on tumor progression. MicroRNAs (miRNAs) in extracellular vesicles (EVs) secreted from cancer cells may contribute to this process. However, the relationship between TAMs and EVs-miRNAs-mediated regulation in esophageal squamous cell carcinoma (ESCC) remains unclear. In the present study, immunoaffinity magnetic beads combined with antiepithelial cell adhesion molecules (EpCAM) were used to isolate and identify EVs-miR-21-5p from the plasma of ESCC patients. An in vitro coculture system was designed to evaluate the effect of esophageal cancer cells with miR-21-5p overexpression on macrophage polarization. We found that phorbol myristate acetate-induced THP-1 macrophages took up EVs-miR-21-5p from EC109 or EC9706 cells and were transformed into M2 macrophages. This, in turn, contributed to the excessive migration and invasion of esophageal cancer cells. The mechanism underlying these changes may involve activation of M2 macrophages by upregulated ESCC-derived EVs-miR-21-5p through the PTEN/AKT/STAT6 pathway. This may result in esophageal cancer cell epithelial-mesenchymal transition (EMT) via TGF-β/Smad2 signaling. Our results indicate positive feedback between M2 macrophage polarization and EMT of esophageal cancer cells in the tumor microenvironment via shuttling of miR-21-5p in tumor-derived EVs.

In this contribution, a new fluorescent probe is presented which is capable of the selective recognition and determination of dodine (DD) from amongst 14 different pesticides. The system utilizes a simple guest-replacement mechanism, which allows for fluorescence turn-on. The probe is constructed from cucurbit[10]uril (Q[10]) and protonated acridine (MeAD), and makes use of the strong fluorescence ability of MeAD in aqueous solution versus the lack of fluorescence for the homoternary inclusion complex MeAD2@Q[10]. The addition of pesticide DD to an aqueous solution of MeAD2@Q[10] resulted in MeAD displacement and subsequent recovery of the strong fluorescence. Interestingly, the similar addition of a number of other common pesticides (13 others were tested herein) failed to result in the recovery of the fluorescence. 1H NMR spectroscopic studies were employed to investigate the guest-replacement fluorescence turn-on mechanism.

Polycyclic Aromatic Sulfur Heterocycles (PASHs) are undesirable compounds in fuel and refined petroleum based products. The sulfur compounds in diesel are limited strictly to an ultra-low concentration according to environment protection rules. Alkyldibenzothiophenes are recalcitrant species in hydrodesulfuriztion process, speciation of dibenzothiophenes in deeply hydrodesulfurized diesel fuel, provides important information to catalyst and process improvement. However, most of the existing analytical methods are unsuitable for identification of ultra-low sulfur compounds in deeply HDS diesel because of the limits of sensitivity. A new method for direct quantitative analysis of alkyldibenzothiophenes in deeply hydrodesulfurized diesel fuel was developed by gas chromatography quadrupole time-of-flight mass spectrometry (GC-Q-TOFMS), which exhibited good linear response, high precision and sensitivity. The practicability of the method was shown by an extensive qualitative and quantitative analysis of alkyld...

The diversity of class D β-lactamases mediating resistance to β-lactams has been increasingly reported recently. In this study, a novel class D oxacillinase named OXA-830 was identified in a fully sequenced Aeromonas simiae strain, which was isolated from sewage discharged from a farm in southern China. OXA-830 shares the highest amino acid identity of 79.3% with an OXA-12-like variant named OXA-725. When expressed in E. coli DH5α, OXA-830 conferred resistance to penicillins and selected β-lactamase inhibitors but not to cephalosporins and carbapenems. Kinetic analysis of OXA-830 revealed a broad substrate profile including penicillins, cefazolin, cefoxitin, and ceftazidime but not carbapenems. The hydrolytic activity was significantly inhibited by sulbactam, followed by tazobactam, but was less effectively inhibited by clavulanic acid. The bla OXA- 830 gene was located on the A. simiae A6 chromosome and the bla OXA- 830-related region was bracketed by a pair of perfect inverted repeats.

The genusCitrobacteris an opportunistic pathogen causing infections in animals, and the published data for its resistance to florfenicol are scarce. In this study, we investigated the antimicrobial susceptibility and molecular characteristics of florfenicol resistance genes amongCitrobacterisolates from animal and relevant environmental samples and conducted a comparative analysis of a multidrug-resistantCitrobacter freundiistrain isolated from a rabbit. Among 20Citrobacterstrains isolated from animal samples, resistance was most commonly observed to ampicillin (100%), tetracycline (75%), streptomycin (65%), florfenicol (60%), chloramphenicol (60%), and aztreonam (50%), while all the strains found in environmental samples were resistant to few antibiotics. The florfenicol resistance genefloRwas detected in 12 isolates (48%, 12/25) from animal samples, and all of thefloR-positive isolates were resistant to florfenicol with minimum inhibitory concentration (MIC) values ≥256 μg/mL. Sequencing and comparative analysis of the plasmids from a multidrug-resistantC. freundiiisolate named R47 showed that thefloR-containing region in the plasmid pR47-54 was a truncated transposon-like structure and could be found on both plasmids and chromosomes of bacteria of either animal or human origin. Furthermore, a range of antimicrobial and metal resistance genes associated with mobile genetic elements could be identified in pR47-54 and the other plasmid pR47-309 ofC. freundiiR47. These results provide in-depth views into the phenotypic and molecular characteristics ofCitrobacterisolates recovered from animal and relevant environmental samples, as well as highlight the role horizontal gene transfer plays in the dissemination of plasmid-encoded resistance genes.

The biological signal molecule nitric oxide (NO) was found to induce biofilm dispersal across a range of bacterial species including Pseudomonas aeruginosa, which led to its consideration for therapeutic strategies to treat biofilms and biofilm-related infections. However, despite the clear link between NO and the bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), a secondary messenger molecule in bacteria that controls the transition between planktonic cells and biofilms, the direct NO sensor that can transmit NO signal into intracellular changes and c-di-GMP levels has not been fully elucidated in P. aeruginosa. It has also been observed that biofilms are often not completely dispersed after exposure to NO and multiple-doses of NO do not improve biofilm dispersal. To better understand those phenomena, to identify putative NO binding receptors and to elucidate the molecular pathway of NO induced dispersal, this study has successfully created transcriptomic profiles of both messenger RNA and small, non-coding RNA in P. aeruginosa untreated planktonic cells and biofilms as well as the cells remain within biofilms after NO treatment and NO dispersed cells. Based on the RNA-Seq data, this study has highlighted several new targets that may be involved in NO induced dispersal. Moreover, this research has linked two important environmental signals (iron and NO) with their roles in biofilm development. Furthermore, it was found that the transcriptional factor FhpR can sense NO to trigger production of the NO binding protein, flavohemoglobin Fhp, which was linked to incomplete biofilm dispersal. Overall, work presented in this thesis has addressed the mechanisms of NO induced biofilm dispersal in P. aeruginosa and offered new perspectives for improving the use of NO in biofilm control strategies via using imidazole to inhibit Fhp and using iron chelators to control iron concentrations in the environment. Doctor of Philosophy

Wide input wide output converters are popular for their versatility in different bus systems. The voltage variation is four times as both input and output voltage vary two times. At the same time, high input voltage can effectively reduce bus loss and the volume and weight. When the input voltage is up to 800 V, current 650 V GaN devices cannot be directly used. A stacked bridge structure is used, ensuring the application of 650 V GaN devices and reducing dv/dt to 20 kV/μs, even when the input voltage is 800 V. The LLC resonant converters are well-known for its high efficiency, compact and wide range of ZVS. However, on the occasion when input voltage is 400-800V and output voltage is 22-40 V whose voltage range varieties four times, a single stage LLC converter is hardly suitable to maintain high efficiency and high power density because the switching frequency variation has to be considerably large and the magnetics cannot be optimally designed. A two-stage solution consisting of a LLC-DCX and three-phase interleaving synchronous buck converters are proposed to maintain high efficiency. All GaN HEMTS are applied and the converter can run up to 1MHz to achieve high power density. The analysis of the influence of parasitic junction capacitance of the rectifier diodes on the primary-side ZVS realization is given. A 2-kW GaN-based prototype with 400-800 V input and 22-40 V output was built to verify the theoretical analysis. The converter can achieve power density of 130 W/in3 and peak efficiency of 93.8%.

Aim. To investigate the effect of Furostanol Saponins from Allium Macrostemon Bunge Bulbs (FSAMB) on platelet aggregation rate of rats with coronary heart disease and discuss the mechanism of FSAMB affecting the platelet aggregation rate through PI3K/Akt pathway. We established the rat models with coronary heart disease (CHD) and prepared the platelet-rich plasma. The effect of different concentrations of FSAMB on platelet aggregation in SD rats induced by ADP was observed in vitro and in vivo. And Lactate Dehydrogenase (LDH), Creatine Kinase-MB Form (CK-MB), and Cardiac Troponin I (cTnI) are detected in the blood to know the level of damage to heart cells. The expansion of platelets in the immobilized fibrinogen in different concentrations of FSAMB was observed. Western blot was conducted to detect the phosphorylation level of protein kinase B (also known as Akt) and the expression level of phosphoinositide 3-kinase (PI3K). We found that FSAMB had a significant inhibitory effect on the ADP-induced platelet aggregation in vitro. Intragastric administration of FSAMB also inhibited platelet aggregation induced by ADP in rats. LDH, CK-MB, and cTnI levels in serum of rats in FSAMB (672 mg/kg) group were lower than those in the model control group after the intervention (P

Due to inappropriate use, florfenicol resistance is becoming increasingly serious among animal respiratory tract and gut bacteria. To detect the florfenicol resistance mechanism among Enterobacteriaceae bacteria, 292 isolates from animal feces were examined. The agar dilution method was conducted to determine the minimum inhibitory concentration (MIC) for florfenicol, and polymerase chain reaction (PCR) was performed to detect florfenicol resistance genes. To further explore the molecular mechanism of florfenicol resistance, the whole-genome Leclercia adecarboxylata R25 was sequenced. Of the strains tested, 61.6% (180/292) were resistant to florfenicol, 64.4% (188/292) were positive for floR, and 1.0% (3/292) for cfr. The whole-genome sequence analysis of L. adecarboxylata R25 revealed that the floR gene is carried by a transposon and located on a plasmid (pLA-64). Seven other resistance genes are also encoded on pLA-64, all of which were found to be related to mobile genetic elements. The sequences sharing the greatest similarities to pLA-64 are the plasmids p02085-tetA of Citrobacter freundii and p234 and p388, both from Enterobacter cloacae. The resistance gene-related mobile genetic elements also share homologous sequences from different species or genera of bacteria. These findings indicate that floR mainly contributes to the high rate of florfenicol resistance among Enterobacteriaceae. The resistance gene-related mobile genetic elements encoded by pLA-64 may be transferred among bacteria of different species or genera, resulting in resistance dissemination.

The fill factor (FF) is a fatal parameter to determine the power conversion efficiency (PCE) of perovskite solar cells. Especially, for the large area solar cells and modules, the low FF is the bottleneck towards the high PCE. The FF is highly correlated with the carrier recombination caused by defects at interfaces. Herein, we propose that ultra-thin inorganic alkali metal fluorides interlayer passivate the interface defects by vapor evaporation method at the perovskite/electron transport layer (ETL) interface. We confirmed that the alkali metal fluorides (AF) layer can function as both defect passivation layer and physical barrier layer, showing the significant enhancement of PCE and ambient stability. Eventually, we achieve the highest FF (80.6%) for 1 cm2 size and highest FF (73.1%) for 10.8 cm2 size perovskite solar cell by potassium fluoride (KF) as passivation layer. This functional interlayer strategy paves the way to resolve the industrial requirements with low cost, high fill factor large area planar perovskite solar cells.

Sodium carboxymethyl cellulose (NaCMC) and chitosan (CS) are successfully combined via amidation, and the obtained product, CMC-CS-A, is used for the adsorption of toxic indigo blue (IB) for the first time. The results of control experiments indicate that the adsorption performance of CMC-CS-A is superior to that of NaCMC, CS, and the composites of NaCMC and CS integrated via electrostatic attractions (CMC-CS-E), which can be attributed to the unique interconnected porous network structure of the as-prepared CMC-CS-A. The mass fraction of CS in the CMC-CS-A is also investigated to achieve the best adsorption of IB, and it reveals that satisfactory removal of IB can be achieved at the CMC-CS-A (50 wt%). Important parameters such as contact time, temperature and initial concentration are discussed in detail in this work. Finally, adsorption isotherms and adsorption kinetics are investigated and compared by using classic models, and the results indicate that the adsorption fits well with the Langmuir isotherm model and the pseudo-second-order kinetic model. It opens a new avenue for the effective and convenient treatment of textile wastewater with integrated natural biopolymers.

Mercaptosuccinic acid (MSA) molecules were inserted into potato starch, leading to the breaking of intrinsic H-bonds within macromolecular chains of starch and the formation of intermolecular H-bonds between MSA and starch, which could be verified by Fourier transform infrared spectroscopy (FT-TR). MSA modified porous starch xerogels (PSX/MSA) were obtained after freeze-drying the MSA modified starch, and they were characterized by field emission scanning electron microscopy (FESEM), exhibiting the intriguing porous structure due to the separation of starch chains by MSA molecules. The PSX/MSA were then used as the adsorbents to remove gardenia yellow (GY), a natural colorant with genotoxicity. Due to the porous structure of PSX and the introduced carboxyl groups from MSA, the adsorption capacity of the PSX/MSA was much higher than that of the starch xerogels alone (SX). The adsorption behaviors of GY by the PSX/MSA fitted both the Freundlich isotherm model and the pseudo-second-order kinetic model, and the efficient adsorption of GY suggested that the PSX/MSA might be potential adsorbents for the removal of dyes from contaminated aquatic systems.

Turmeric, a rhizome of Curcumin longa L. is widely used as both a spice and an herbal medicine. The traditional use of turmeric in gastroenterology is mainly based on its choleretic activity. The aim of this study is to determine the effects of turmeric on bile flow (BF) and total bile acids (TBAs) excretion in a bile fistula rat model after acute duodenal administration. A significant dose-dependent enhancement in both BF and TBAs was detected after treatment with the turmeric decoctions which suggested the choleretic activity was bile acid-dependent secretion. In order to direct the active group of compounds, aqueous (AE), ethyl acetate (EtOAc), and petroleum ether (PE) extracts were investigated. The EtOAc and PE extracts showing high effects were purified to locate the active ingredients. Three curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) and 2 sesquiterpenes (bisacurone B and ar-turmerone) were isolated. It was found Bisacurone B was the most potent choleretic ingredient followed by ar-turmerone, bisdemethoxycurcumin demethoxycurcumin, and then curcumin. The amounts of the active ingredients were quantitatively analyzed by high-performance liquid chromatography. The EtOAc and PE extracts had high sesquiterpenes and curcuminoids content, while the AE extract had poor content of sesquiterpenes and curcuminoids which affected neither BF nor TBAs. Based on the results of multiple linear regression analysis, the content of BIS and TUR were dominant factors (P < 0.01) of controlling BL and TBAs in EtOAC and PE extracts.

Besides the development of effective catalysts, surface property of the electrode is also crucial in electrocatalytic hydrogen evolution. Herein, a nanosheet array electrode of CoSx-Ni3S2/NF was designed by a facile hydrothermal process. Particularly, the obtained electrode was endowed with superhydrophilicity and superaerophobicity, which not only facilitates to the exposure of active sites, but also alleviates the “bubble shielding effect” for gas diffusion. Consequently, the nanosheet array electrode demonstrated excellent full water splitting activities in alkaline condition, which only need a low voltage of 1.63 V to achieve a current density of 100 mA cm–2 and can keep a long durability for 20 h at 20 mA cm−2. Additionally, the production of hydrogen powered by the electricity derived from solar and wind energy utilizing the CoSx-Ni3S2/NF as the electrocatalysts in laboratory condition was also simulated. This work will provide a novel perspective for HER research from the engineering of electrode-architecture.

Diacylglycerol acyltransferase (DGAT) enzymes are involved in triglyceride (TG) biosynthesis. GSK3008356 is a potent and selective DGAT1 inhibitor that was administered orally in a 2-part study as double-blind, randomized, placebo-controlled single doses (SDs) and repeat doses (RDs) in healthy subjects to investigate its pharmacokinetics, pharmacodynamics, and safety/tolerability. Gastrointestinal adverse events were considered drug related and increased with dose and when given as multiple doses. In the SD part (n = 80), GSK3008356 was dosed from 5 to 200 mg as single or multiple doses per day. In the RD part (n = 24), GSK3008356 was dosed twice daily at 1, 3, and 10 mg for 14 days. GSK3008356 was generally well tolerated in the SD and RD parts. With single doses, absorption was rapid (median tmax , 0.5-1.5 hours), whereas single-day divided dosing resulted in higher tmax . Following 14-day RD oral administration, GSK3008356 was also rapidly absorbed, with median tmax ranging from 0.5 to 0.75 hours on days 1 and 14. Estimated mean half-life ranged from 1.5 to 4.6 hours with SDs and 1.3 to 2.1 hours with RDs. Exposure of GSK3008356 was largely dose proportional after RDs. At higher doses, there was a trend toward lower absolute postprandial TG level in some subjects.

Nitric oxide (NO), which induces biofilm dispersal, is a promising strategy for biofilm control in both clinical and industrial contexts. However, competing environmental signals may reduce the efficacy of NO. The results presented here suggest that the presence of iron represents one such environmental cue that antagonizes the activity of NO as a biofilm-dispersing agent. Based on this understanding, we developed a strategy to enhance dispersal by combining NO with an iron-scavenging agent. Overall, this study links two important environmental signals, iron and NO, with their roles in biofilm development and suggests new ways for improving the use of NO in biofilm control strategies., While both iron and nitric oxide (NO) are redox-active environmental signals shown to regulate biofilm development, their interaction and roles in regulating biofilms have not been fully elucidated. In this study, exposure of Pseudomonas aeruginosa biofilms to exogenous NO inhibited the expression of iron acquisition-related genes and the production of the siderophore pyoverdine. Furthermore, supplementation of the culture medium with high levels of iron (100 μM) counteracted NO-induced biofilm dispersal by promoting the rapid attachment of planktonic cells. In the presence of iron, biofilms were found to disperse transiently to NO, while the freshly dispersed cells reattached rapidly within 15 min. This effect was not due to the scavenging of NO by free iron but involved a cellular response induced by iron that led to the elevated production of the exopolysaccharide Psl. Interestingly, most Psl remained on the substratum after treatment with NO, suggesting that dispersal involved changes in the interactions between Psl and P. aeruginosa cells. Taken together, our results suggest that iron and NO regulate biofilm development via different pathways, both of which include the regulation of Psl-mediated attachment. Moreover, the addition of an iron chelator worked synergistically with NO in the dispersal of biofilms. IMPORTANCE Nitric oxide (NO), which induces biofilm dispersal, is a promising strategy for biofilm control in both clinical and industrial contexts. However, competing environmental signals may reduce the efficacy of NO. The results presented here suggest that the presence of iron represents one such environmental cue that antagonizes the activity of NO as a biofilm-dispersing agent. Based on this understanding, we developed a strategy to enhance dispersal by combining NO with an iron-scavenging agent. Overall, this study links two important environmental signals, iron and NO, with their roles in biofilm development and suggests new ways for improving the use of NO in biofilm control strategies.

The biological signal molecule nitric oxide (NO) was found to induce biofilm dispersal across a range of bacterial species, which led to its consideration for therapeutic strategies to treat biofilms and biofilm-related infections. However, biofilms are often not completely dispersed after exposure to NO. To better understand this phenomenon, we investigated the response of Pseudomonas aeruginosa biofilm cells to successive NO treatments. When biofilms were first pretreated with a low, noneffective dose of NO, a second dose of the signal molecule at a concentration usually capable of inducing dispersal did not have any effect. Amperometric analysis revealed that pretreated P. aeruginosa cells had enhanced NO-scavenging activity, and this effect was associated with the production of the flavohemoglobin Fhp. Further, quantitative real-time reverse transcription-PCR (qRT-PCR) analysis showed that fhp expression increased by over 100-fold in NO-pretreated biofilms compared to untreated biofilms. Biofilms of mutant strains harboring mutations in fhp or fhpR , encoding a NO-responsive regulator of fhp , were not affected in their dispersal response after the initial pretreatment with NO. Overall, these results suggest that FhpR can sense NO to trigger production of the flavohemoglobin Fhp and inhibit subsequent dispersal responses to NO. Finally, the addition of imidazole, which can inhibit the NO dioxygenase activity of flavohemoglobin, attenuated the prevention of dispersal after NO pretreatment and improved the dispersal response in older, starved biofilms. This study clarifies the underlying mechanisms of impaired dispersal induced by repeated NO treatments and offers a new perspective for improving the use of NO in biofilm control strategies.

A new method for analysis of saturates in vacuum residue was developed by solid phase extraction and field desorption time-of-flight mass spectrometry. Vacuum residue was separated into saturates, aromatics, and resins by solid phase extraction. Saturates were ionized by field desorption source which produces primarily unfragmented mass spectra. This method could be applied for carbon number and compound-type distribution analysis of paraffins and 1-ring to 6-ring cycloparaffins in different vacuum residues. Molecular composition of saturates from various vacuum residue were characterized successfully by the developed method.