Identification and pathogenicity analysis of a novel non-tuberculous mycobacterium clinical isolate with nine-antibiotic resistance

With mycobacteriosis increasing, the study of non-tuberculous mycobacteria is imperative for clinical therapy and management. Nontuberculous mycobacteria are naturally resistant to most anti-tuberculosis drugs. Accordingly, it is important to decipher the biology of the novel non-tuberculous mycobacteria through complete genomic analysis of novel pathogenic mycobacteria. We describe Mycobacterium sinense JDM601, a novel, slow-growing mycobacterium of the Mycobacterium terrae complex resistant to nine antibiotics, by clinical presentation, cultural and biochemical characteristics, minimal inhibitory concentrations, and genome-sequencing analysis. JDM601 is closest to Mycobacterium nonchromogenicum according to mycolic acid composition, but closest to Mycobacterium algericum sp. nov according to 16S rDNA. JDM601 is resistant to isoniazid, streptomycin, rifampin, euteropas, protionamide, capromycin, ciprofloxacin, amikacin and levofloxacin but not ethambutol. The clinical information, mycolic acid composition, and virulence genes indicate that JDM601 is an opportunistic pathogen.     

MRI of the upper airway in non-snoring males

Objective

The aims of the study were to clarify the characteristics of the upper airway in children and to assess the effects of age on the upper airway.

Materials and methods

The study was part of a long-term observational research project on non-snoring males. The cohort of children comprised 28 volunteers with an age range of 8–12 years. The children group was compared to three different groups of adults: a youth group (n?=?30, age range 22–29 years), a middle-aged group (n?=?53, age range 36–57 years) and a senior group (n?=?31, age range 70–78 years). All children were demonstrated to be non-snorers by polysomnography (PSG). MRI scans were performed on all subjects in a state of wakefulness using a custom-made instrument.

Results

In addition to the total airway volume (p?=?0.000), the volume of each airway region was significantly smaller in children than in adults. Although the minimum cross-sectional area of the airway in children was usually measured in the velopharynx, it located to the nasopharynx in 7.14?% of cases. However, the nasopharynx continued to increase in size with increasing age.

Conclusion

Like many other physical parameters, the upper airway is significantly smaller in children than adults. The upper airway of children might be affected by the pharyngeal lymphatic ring. An increase in size of the nasopharynx was not only an age-related change, but probably also represents an anatomic advancement in non-snoring subjects.     

Room-temperature synthesis of water-dispersible sulfur-doped reduced graphene oxide without stabilizers

Sulfur-Doped graphene has attracted significant attention because of its potential uses in sensors, catalysts, and energy storage applications. In conventional approaches, the sulfur-doped graphene is fabricated with graphene oxide and sulfur-containing compounds through thermal annealing or hydrothermal process, which generally involves special equipment and heat treatment, and requires additional stabilizers to make it solution-processable. In this work, we report a facile one-step approach to synthesize water-dispersible sulfur-doped reduced graphene oxide (S-rGO). Graphene oxide (GO) could be readily reduced and converted to S-rGO simultaneously by directly mixing GO dispersion with hydrosulfide hydrate (NaSH·xH₂O) at room temperature. The sulfur doping is confirmed by high resolution S 2p XPS spectrum and element mapping. The colloidal dispersion state of S-rGO is confirmed by the investigation of Tyndall effect, the zeta potential and particle size distribution measurement. Compared with previously reported strategies, NaSH can initiate the reduction and sulfur doping at room temperature, demand no heat treatment, require no equipment and form stable aqueous S-rGO dispersion without using any stabilizer. These advantages will facilitate large-scale production of water-dispersible (sulfur doped) graphene and further boost their applications in sensors, catalysts and energy storage devices.

Room-temperature synthesis of sulfur-doped reduced graphene oxide, which can form stable aqueous dispersion without using any stabilizer.     

Regioselective O/C phosphorylation of α-chloroketones: a general method for the synthesis of enol phosphates and β-ketophosphonates via Perkow/Arbuzov reaction

A regioselective O/C phosphorylation of α-chloroketones with trialkyl phosphites was performed for the first time, which employed solvent-free Perkow reaction and NaI-assisted Arbuzov reaction under mild conditions respectively. Versatile enol phosphates were prepared in good to excellent yields as well as β-ketophosphinates.

A highly regioselective O/C phosphorylation of α-chloroketones with trialkyl phosphites was developed in the preparation of enol phosphates and β-ketophosphonates.     

Phosphorus/nitrogen co-doped and bimetallic MOF-derived cathode for all-solid-state rechargeable zinc–air batteries

With the merits of high safety and energy density, all-solid-state zinc–air batteries possess potential applications in flexible and wearable electronic devices. Especially, the air cathodes with bifunctional catalytic activity, i.e. oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have been received enormous attention. In this work, we provide a novel phosphorus/nitrogen co-doped and bimetallic metal–organic framework (MOF)-derived cathode configurated with phosphorus-doped bimetallic FeNi alloys and a nitrogen-doped porous carbon layer loaded on graphene (P–FeNi/NC@G). The P–FeNi/NC@G electrode exhibits a superior OER activity with an overpotential of 310 mV at 10 mA cm⁻² and an ORR performance with a half-wave potential of 0.81 V. With P–FeNi/NC@G as the air cathode, the integrated all-solid-state rechargeable zinc–air battery presents a high open-circuit voltage of 1.53 V, a high peak power density of 159 mW cm⁻², a small charge–discharge voltage gap of 0.73 V at 5 mA cm⁻², as well as excellent long-term stability up to 144 cycles. This work not only expands the air cathode materials database but also develops a new co-doped synthesis method that can be utilized to fabricate a cathode with promoted catalytic efficiency, resulting in improved performance for an all-solid-state zinc–air battery.

The bimetallic FeNi-MOFs are employed to fabricate P–FeNi and N–carbon co-doped bifunctional catalyst. Due to the enhanced catalytic performance, the peak power density of all-solid-state zinc–air battery is 159 mW cm⁻².     

The effect of surfactants on hydrate particle agglomeration in liquid hydrocarbon continuous systems: a molecular dynamics simulation study

Anti-agglomerants (AAs), both natural and commercial, are currently being considered for gas hydrate risk management of petroleum pipelines in offshore operations. However, the molecular mechanisms of the interaction between the AAs and gas hydrate surfaces and the prevention of hydrate agglomeration remain critical and complex questions that need to be addressed to advance this technology. Here, we use molecular dynamics (MD) simulations to investigate the effect of model surfactant molecules (polynuclear aromatic carboxylic acids) on the agglomeration behaviour of gas hydrate particles and disruption of the capillary liquid bridge between hydrate particles. The results show that the anti-agglomeration pathway can be divided into two processes: the spontaneous adsorption effect of surfactant molecules onto the hydrate surface and the weakening effect of the intensity of the liquid bridge between attracted hydrate particles. The MD simulation results also indicate that the anti-agglomeration effectiveness of surfactants is determined by the intrinsic nature of their molecular functional groups. Additionally, we find that surfactant molecules can affect hydrate growth, which decreases hydrate particle size and correspondingly lower the risk of hydrate agglomeration. This study provides molecular-level insights into the anti-agglomeration mechanism of surfactant molecules, which can aid in the ultimate application of natural or commercial AAs with optimal anti-agglomeration properties.

Schematic of anti-agglomeration effect of surfactants promoting gas hydrate particle dispersion.