Two-dimensional cobalt metal-organic frameworks for efficient C3H6/CH4 and C3H8/CH4 hydrocarbon separation

A Co-based two-dimensional (2D) microporous metal-organic frameworks (UPC-32) with narrow distance between layers and layers (3.8 Å) exhibits high selectivity of C₃H₆/CH₄ (31.46) and C₃H₈/CH₄ (28.04) at 298 K and 1 bar. It is the first 2D Co-MOF that showed selective separation of C3 hydrocarbon from CH₄.     

Synthesis of 1,8-naphthalimide-based fluorescent nano-probes and their application in pH detection

Fluorescent nano-probes with particle sizes of 20 nm, 120 nm and 300 nm for proton were prepared through click reaction. The photophysical properties of the nano-probes were mainly affected by the particle size.     

HTLC: A Viable Approach to Fast LC of Biogenic Amines in Food with Legacy Equipment

Nowadays, there is a demand for fast liquid chromatography (LC) of biogenic amines in food with the equipment available in the average laboratory. To this end, high-temperature liquid chromatography (HTLC) is presented in this study as a viable option, working on a conventional LC platform at moderately high temperatures up to 80 °C. The LC platform was adapted by including an appropriate length of stainless-steel microbore tubing as a preheater. Biogenic amines as benzoyl derivatives showed good thermostability on a thermally rugged column (150?×?4.6 mm, 5 µm). As a model application the HTLC conditions were developed for wine separation. The separation selectivity changed considerably with temperature in the range 36–84 °C, and baseline resolution was obtained only at temperatures well above ambient. At 73 °C oven temperature, the system allowed a flow rate as high as 3 mL min^?1 with the backpressure not exceeding 195 bar (2800 psi). The separation took less than 5 min, comparably fast to documented fast LC separations, and typically at least three to five times faster than a conventional separation.     

Synthesis,properties and mechanism of photodegradation of core–shell structured upconversion luminescent NaYF4:Yb3+,Er3+@BiOCl

Microspherical bismuth oxychloride (BiOCl) can only utilize ultraviolet (UV) light to promote photocatalytic reactions. To overcome this limitation, a uniform and thin BiOCl nanosheet was synthesized with a particle size of about 200 nm. As results of UV–visible diffuse reflectance spectroscopy showed, the band gap of this nanostructure was reduced to 2.78 eV, indicating that the BiOCl nanosheet could absorb and utilize visible light. Furthermore, the upconversion material NaYF₄ doped with rare earth ions Yb³⁺ and Er³⁺ emitted visible light at 410 nm following excitation with near‐infrared (NIR) light (980 nm), which could be utilized by BiOCl to produce a photocatalytic reaction. To produce a high‐efficiency photocatalyst (NaYF₄:Yb³⁺,Er³⁺@BiOCl), BiOCl‐loaded NaYF₄:Yb³⁺,Er³⁺ was successfully synthesized via a simple two‐step hydrothermal method. The as‐synthesized material was confirmed using X‐ray diffraction, scanning electron microscopy, X‐ray photoelectron spectroscopy as well as other characterizations. The removal ratio of methylene blue by NaYF₄:Yb³⁺,Er³⁺@BiOCl was much higher than that of BiOCl alone. Recycling experiments verified the stability of NaYF₄:Yb³⁺,Er³⁺@BiOCl, which demonstrated excellent adsorption, strong visible‐light absorption and high electron–hole separation efficiency. Such properties are expected to be useful in practical applications, and a further understanding of the NIR‐light‐responsive photocatalytic mechanism of this new catalytic material would be conducive to improving its structural design and function.     

A multifunctional blue phase liquid crystal lens based on multi-electrode structure

A blue phase liquid crystal (BPLC) lens with multifunction using multi-electrode structure and a dielectric layer with high dielectric constant is proposed. The refractive index of the BPLC can be changed flexibly in different regions. Some functional or technical requirements such as switch between positive and negative lenses can be achieved. The lens reveals a good parabolic refractive index distribution and focus adjustment capacity simultaneously. The applied voltage on the electrodes is regular and computable. To decrease the applied voltage of the proposed lens with a large diameter, a drive-type adopted Fresnel lens is introduced.     

Electrophoretic Determination of Formaldehyde in Human Urine: Application to Alzheimer’s Disease

The primary clinical diagnosis of Alzheimer’s disease is mainly based on medical history and neuropsychiatric inventory. It is urgent to seek biological indicators with better sensitivity and higher specificity to clinically diagnose and evaluate Alzheimer’s disease. In this work, an electrophoretic method based on 2-thiobarbituric acid derivatization and amperometric detection was developed to determine formaldehyde as a urinary biomarker of Alzheimer’s disease. Under the optimum conditions, the formaldehyde derivative was well separated from the coexisting interferences in urine sample. The limit of detection for formaldehyde was 80.0?nM (2.4?ng/?mL) based on an electrophoretic stacking technology. The average recovery values were in the range of 91.7–110%, and the relative standard deviation values were less than 4.1%. This method has been applied to analyze human urine samples from healthy volunteers and patients with different degrees of Alzheimer’s disease. The assay results showed that the content of urinary formaldehyde in patients suffering Alzheimer’s disease was significantly higher than that in healthy subjects (P?相似文献   

MoB/g‐C3N4 Interface Materials as a Schottky Catalyst to Boost Hydrogen Evolution

Proton adsorption on metallic catalysts is a prerequisite for efficient hydrogen evolution reaction (HER). However, tuning proton adsorption without perturbing metallicity remains a challenge. A Schottky catalyst based on metal–semiconductor junction principles is presented. With metallic MoB, the introduction of n‐type semiconductive g‐C₃N₄ induces a vigorous charge transfer across the MoB/g‐C₃N₄ Schottky junction, and increases the local electron density in MoB surface, confirmed by multiple spectroscopic techniques. This Schottky catalyst exhibits a superior HER activity with a low Tafel slope of 46 mV dec^?1 and a high exchange current density of 17 μA cm^?2, which is far better than that of pristine MoB. First‐principle calculations reveal that the Schottky contact dramatically lowers the kinetic barriers of both proton adsorption and reduction coordinates, therefore benefiting surface hydrogen generation.     

Total Synthesis of Bryostatin 8 Using an Organosilane‐Based Strategy

Convergent total synthesis of bryostatin 8 has been accomplished by an organosilane‐based strategy. The C ring is constructed stereoselectively through a geminal bis(silane)‐based [1,5]‐Brook rearrangement, and the B ring through geminal bis(silane)‐based Prins cyclization, thus efficiently joining the northern and southern parts of the molecule.     

Imaging of Colorectal Cancers Using Activatable Nanoprobes with Second Near‐Infrared Window Emission

Fluorescent probes in the second near‐infrared window (NIR‐II) allow high‐resolution bioimaging with deep‐tissue penetration. However, existing NIR‐II materials often have poor signal‐to‐background ratios because of the lack of target specificity. Herein, an activatable NIR‐II nanoprobe for visualizing colorectal cancers was devised. This designed probe displays H₂S‐activated ratiometric fluorescence and light‐up NIR‐II emission at 900–1300 nm. By using this activatable and target specific probe for deep‐tissue imaging of H₂S‐rich colon cancer cells, accurate identification of colorectal tumors in animal models were performed. It is anticipated that the development of activatable NIR‐II probes will find widespread applications in biological and clinical systems.     

High‐Flux Membranes Based on the Covalent Organic Framework COF‐LZU1 for Selective Dye Separation by Nanofiltration

Covalent organic frameworks (COFs) are attractive candidates for advanced water‐treatment membranes owing to their high porosity and well‐organized channel structures. Herein, the continuous two‐dimensional imine‐linked COF‐LZU1 membrane with a thickness of only 400 nm was prepared on alumina tubes by in situ solvothermal synthesis. The membrane shows excellent water permeance (ca. 760 L m^?2 h^?1 MPa^?1) and favorable rejection rates exceeding 90 % for water‐soluble dyes larger than 1.2 nm. The water permeance through the COF‐LZU1 membrane is much higher than that of most membranes with similar rejection rates. Long‐time operation demonstrates the outstanding stability of the COF‐LZU1 membrane. As the membrane has no selectivity for hydrated salt ions (selectivity <12 %), it is also suitable for the purification of dye products from saline solutions. The excellent performance and the outstanding water stability render the COF‐LZU1 membrane an interesting system for water purification.