Highly sensitive trace oxygen sensing based on far-ultraviolet absorption spectroscopy.

High-sensitivity trace oxygen sensing based on far-ultraviolet absorption spectroscopy was realized. The far-ultraviolet absorption spectrum of oxygen in the wavelength range of 170-200 nm at normal pressure was measured, and the maximum oscillation absorption peak occurred close to 180.18 nm. Through error analysis, the optimal wavelength range for accurate and sensitive oxygen measurements by ultraviolet absorption spectroscopy was identified as 180-189 nm. A total column (CL) calibration curve for oxygen was established, and the maximum optical path length (L1) of the system was determined to be 0.75(3) m by comparing the oxygen absorption with and without the sample cell. The oxygen detection sensitivity was 232 m-1, and the lowest detection limit was 12 ppm at the L1 optical path length. The highly sensitive trace oxygen sensing based on far-ultraviolet absorption spectroscopy exhibited significant potential for application with regard to nitrogen protection.

Discovery of a novel and selective cathepsin L inhibitor with anti-metastatic ability in vitro and in vivo against breast cancer cells.

Asperphenamate is a natural product that has attracted considerable interest from researchers worldwide. In the last decade, aiming to increase the biological activity and improve druggability, modifications of the A-ring moiety in asperphenamate have been performed. Our laboratory has also recently reported functional derivatizations of the A ring and studied its effect on the inhibition of cysteine cathepsin L. However, the functional significance of the B-ring fragment toward cathepsin L has not been evaluated thus far. In this paper, forty-four derivatives of the B-ring substituted with different N-phenylsulfonyl groups were designed and synthesized. Among them, the paratrifluromethyl analog B-2a and the 2, 4-difluoro-5-chloro derivative B-11b showed more potent inhibitory activity against cathepsin L than the control compound, ABR, which displayed the strongest inhibitory effect on cathepsin L and S among all reported asperphenamate derivatives. In particular, compound B-2a showed more pronounced selectivity against cathepsin L than the other derivatives. Molecular docking revealed that the N-phenylsulfonylamide moiety was vital for the interactions between B-2a and cathepsin L. Moreover, B-2a displayed no toxicity against normal cells. Therefore, compound B-2a was selected for further studies. Wound-healing assays, Transwell chamber assays and breast cancer lung metastasis mouse models demonstrated that B-2a exhibited antimetastatic ability in vitro and in vivo.

Endowing g-C3 N4 Membranes with Superior Permeability and Stability by Using Acid Spacers.

g-C3 N4 membranes were modulated by intercalating molecules with SO3 H and benzene moieties between layers. The intercalation molecules break up the tightly stacking structure of g-C3 N4 laminates successfully and accordingly the modified g-C3 N4 membranes give rise to two orders magnitude higher water permeances without sacrificing the separation efficiency. The sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO)/g-C3 N4 with a thickness of 350 nm presents an exceptionally high water permeance of 8867 L h-1 m-2 bar-1 and 100 % rejection towards methyl blue, while the original g-C3 N4 membrane with a thickness of 226 nm only exhibits a permeance of 60 L h-1 m-2 bar-1 . Simultaneously, SO3 H sites firmly anchor nitrogen with base functionality distributing onto g-C3 N4 through acid-base interactions. This enables the nanochannels of g-C3 N4 based membranes to be stabilized in acid, basic, and also high-pressure environments for long periods.

Ultrahigh Lithium Selective Transport in Two-Dimensional Confined Ice.

Inspired by selective ion transport in biological membrane proteins, researchers developed artificial ion channels that sieve monovalent cations, catering to the increasing lithium demand. In this work, we engineered an ion transport channel based on the confined ice within two-dimensional (2D) capillaries and found that the permselectivity of monovalent cations depends on the anisotropy of the confined ice. Particularly, the 2D confined ice showed an anomalous lithium selective transport along the (002) direction in the vermiculite capillary, with the Li+/Na+ and Li+/K+ permselectivity reaching up to 556 ± 86 and 901 ± 172, respectively, superior to most ion-selective channels. However, the 2D confined ice along the (100) direction showed less Li+ permselectivity. Additionally, the anisotropy of 2D confined ice can be tuned by adjusting the interlayer spacing. By providing insights into the ion transport in the 2D confined ice, our work may inspire more design of monovalent ion-selective channels for efficient lithium separation.

Comparison of bioaerosol release characteristics between windrow and trough sludge composting plants: Concentration distribution, community evolution, bioaerosolization behaviour, and exposure risk.

Windrow and trough composting are two mainstream composting methods, but the effect of composting methods on bioaerosol release from sludge composting plants is unclear. The study compared the bioaerosol release characteristics and exposure risks between the two composting methods. The results showed that the bacterial aerosol concentrations in the windrow composting plant ranged from 14,196 to 24,549 CFU/m3, while the fungal aerosol concentrations in the trough composting plant reached 5874 to 9284 CFU/m3; there were differences in the microbial community structures between the two sludge composting plants, and the composting method had a greater effect on bacterial community evolution than on fungal community evolution. The biochemical phase was the primary source of the bioaerosolization behaviour of the microbial bioaerosols. In the windrow and trough composting plants, the bacterial bioaerosolization index ranged from 1.00 to 999.28 and from 1.44 to 24.57, and the fungal bioaerosolization index ranged from 1.38 to 1.59 and from 0.34 to 7.72, respectively. Bacteria preferentially aerosolized mainly in the mesophilic stage, while the peak of the fungal bioaerosolization index appeared in the thermophilic stage. The total non-carcinogenic risks for bacterial aerosols were 3.4 and 2.4, while those for fungi were 1.0 and 3.2 in the trough and windrow sludge composting plants, respectively. Respiration is the main exposure pathway for bioaerosols. It is necessary to develop different bioaerosol protection measures for different sludge composting methods. The results of this study provided basic data and theoretical guidance for reducing the potential risk of bioaerosols in sludge composting plants.

Electrically Modulated Nanofiltration Membrane Based on an Arch-Bridged Graphene Structure for Multicomponent Molecular Separation.

Tunable regulation of molecular penetration through porous membranes is highly desirable for membrane applications in the pharmaceutical and medical fields. However, in most previous reports additional reagents or components are usually needed to provide the graphene-based membranes with responsiveness. Herein, we report tunable arch-bridged reduced graphene oxide (rGO) nanofiltration membranes modulated by the applied voltage. Under a finite voltage of 5 V, the rGO membrane could completely reject organic/anionic molecules. With assistance of the voltage, the positive-charge-modified rGO membrane realized the universal rejection of both cationic and anionic dyes, also showing the valid modulation in harsh organic solvents. The efficient electrical modulation depended on the synergetic effects of Donnan repulsion and size exclusion, benefiting from the electric field enhancement in arch-bridged rGO structures. Furthermore, multicomponent separation was achieved by our electrically modulated rGO-based membranes, demonstrating their potential in practical applications such as pharmaceutical industries.

Measurement of CS2 Absorption Cross-Sections in the 188-215 nm Region at Room Temperature and Atmospheric Pressure.

Carbon disulfide, an important sulfur-containing species, has strong absorption lines in the wavelength range of 188 nm to 215 nm. It is difficult to accurately measure the absorption cross sections of carbon disulfide because carbon disulfide will be easily converted into carbon sulfide when it is exposed to ultraviolet light. In this study, the absorption cross sections of carbon disulfide were measured by reducing carbon disulfide conversion. The factors affecting carbon disulfide conversion, including gas flow rate, ultraviolet light intensity, and duration of illumination, were studied to reduce the conversion of carbon disulfide by controlling experimental conditions in the experiment. Finally, the absorption cross sections of carbon disulfide at room temperature and atmospheric pressure were calculated using the absorption spectrum and the carbon disulfide concentration in the absence of carbon disulfide conversion. The wavelengths of 16 absorption peaks on the carbon disulfide absorption cross sections of the vibration change were marked. Carbon disulfide has the maximum absorption cross section of 4.5 × 10-16 cm2/molecule at a wavelength of 198.10 nm.

Effect of Physical Properties of a Gas on the Refrigeration Temperature Drop of Vortex Tubes Used in Oil and Gas Fields.

The composition of natural gas can vary considerably across different oil and gas fields. Such compositional variation is primarily reflected in the distinctive physical properties of natural gas. However, during practical application in an oil and gas field, a refrigeration temperature drop in a vortex tube is often observed because vortex tubes generally have low intrinsic refrigeration efficiencies. When vortex tubes are applied in oil and gas fields, the utilization of the oil pressure of a natural gas wellhead is often desirable to avoid excessive energy usage from external devices. In this study, a numerical model of a vortex tube was developed, executed, and validated through laboratory experiments. The refrigeration temperature drop values of 12 gases with distinctive physical properties at a total inlet pressure of 0.3 MPa, an inlet temperature of 300 K, and a cooling mass flow ratio of 0.5 were analyzed. The importance of different physical properties was ranked based on the gray correlation method. Additionally, the synergetic effects of the physical properties on the refrigeration temperature drop were analyzed via regression fitting. The results indicate a significant impact of the gas physical properties on the refrigeration temperature drop in the vortex tube. The maximum and minimum refrigeration temperature drop obtained for different gases can differ by up to 16 K. Furthermore, the refrigeration temperature drop in the vortex tube does not change monotonically with any physical property. Instead, it depends on the synergetic effect from the physical properties, which have different levels of influence on it.