Trends in sensitive detection and rapid removal of sulfonamides: A review

Sulfonamides in environmental water, food, and feed are a major concern for both aquatic ecosystems and public health, because they may lead to the health risk of drug resistance. Thus, numerous sensitive detection and rapid removal methodologies have been established. This review summarizes the sample preparation techniques and instrumental methods used for sensitive detection of sulfonamides. Additionally, adsorption and photocatalysis for the rapid removal of sulfonamides are also discussed. This review provides a comprehensive perspective on future sulfonamide analyses that have good performance, and on the basic methods for the rapid removal of sulfonamides.     

Determination of the mass transfer coefficients in direct immersion solid‐phase microextraction

Diffusion of the analytes across the diffusion boundary layers and subsequently through the fiber coatings determines the extraction kinetics of solid‐phase microextraction in aqueous matrices. Besides, the matrix effects can distort the behaviors of the analytes transferring across the diffusion boundary layers. However, these processes were always studied via certain simplification, which often left the mass transfer through the fiber coatings unconsidered and the matrix effects partially investigated. Herein, a comprehensive study on the mass transfer processes in direct immersion solid‐phase microextraction was presented. Under different agitation speeds, it was determined that the mass transfer coefficients across the diffusion boundary layers were three to six orders larger than those through the fiber coatings. However, the mass transfer across the diffusion boundary layers was generally the major rate‐limiting step. In addition, the shuttle effect and the barrier effect, which were responsible for accelerating and retarding the extraction kinetics, respectively, were found to be the dominant matrix effect alternately under different agitation speeds. This study comprehensively illustrated the major rate‐limiting step and the dominant matrix effects through recording the mass transfer coefficients.     

Fabrication of 3D polymeric photonic arrays and related applications

This review article describes the state-of-art methodologies, mainly self-assembly routes, which are in practice to fabricate photonic crystals (PCs) for advanced applications. The self-assembly of colloidal building blocks is an effective, affordable, and tunable approach to fabricate varieties of photonic materials of desired shapes and surface areas. Because of easy fabrication and controlled performance factors, PCs emerged as a potential platform for designing and developing optical devices with desired features such as photonic bandgap, high reflectance/transmittance, low loss, and lasing in the visible range of wavelengths. To develop next-generation optoelectronics and optical system, significant efforts are being made to explore novel and cost-effective fabrication methods to design and develop 3D-PCs platform, which is covered in this mini-review. The challenges, potential alternatives, and prospects of self-assembled 3D PCs are also discussed in this review.     

Nanoaggregate Probe for Breast Cancer Metastasis through Multispectral Optoacoustic Tomography and Aggregation‐Induced NIR‐I/II Fluorescence Imaging

An activatable nanoprobe for imaging breast cancer metastases through near infrared‐I (NIR‐I)/NIR‐II fluorescence imaging and multispectral optoacoustic tomography (MSOT) imaging was designed. With a dihydroxanthene moiety serving as the electron donor, quinolinium as the electron acceptor and nitrobenzyloxydiphenylamino as the recognition element, the probe can specifically respond to nitroreductase and transform into an activated D‐π‐A structure with a NIR emission band extending beyond 900 nm. The activated nanoprobe exhibits NIR emission enhanced by aggregation‐induced emission (AIE) and produces strong optoacoustic signal. The nanoprobe was used to detect and image metastases from the orthotopic breast tumors to lymph nodes and then to lung in two breast cancer mouse models. Moreover, the nanoprobe can monitor the treatment efficacy during chemotherapeutic course through fluorescence and MSOT imaging.     

One‐Step Nucleic Acid Purification and Noise‐Resistant Polymerase Chain Reaction by Electrokinetic Concentration for Ultralow‐Abundance Nucleic Acid Detection

Nucleic acid amplification tests (NAATs)integrated on a chip hold great promise for point‐of‐care diagnostics. Currently, nucleic acid (NA) purification remains time‐consuming and labor‐intensive, and it takes extensive efforts to optimize the amplification chemistry. Using selective electrokinetic concentration, we report one‐step, liquid‐phase NA purification that is simpler and faster than conventional solid‐phase extraction. By further re‐concentrating NAs and performing polymerase chain reaction (PCR) in a microfluidic chamber, our platform suppresses non‐specific amplification caused by non‐optimal PCR designs. We achieved the detection of 5 copies of M. tuberculosis genomic DNA (equaling 0.3 cell) in real biofluids using both optimized and non‐optimal PCR designs, which is 10‐ and 1000‐fold fewer than those of the standard bench‐top method, respectively. By simplifying the workflow and shortening the development cycle of NAATs, our platform may find use in point‐of‐care diagnosis.     

Raman investigation of chemical reaction product in thermal‐treated SiCf/C/Mo/Ti6Al4V composite

SiC fiber‐reinforced titanium matrix composite (TMC) is an interesting material for aerospace industry because of its excellent properties. Characterization of their interfacial reaction product is principal to further optimization of the TMCs. Here we report application of Raman spectroscopy to identify reaction products and their microstructural details in thermal‐treated SiC_f/C/Mo/Ti6Al4V composite. Meanwhile TEM is performed to help explain phenomena in Raman result. Raman line scanning along interface indicates thickness of two sublayers (Ti₅Si₃(C_x) layer next to SiC fiber and TiC_x layer next to matrix). The main Raman result of phase distribution is confirmed by TEM. While a 300‐nm Ti₃SiC₂ layer whose Raman features are similar with nearby Ti₅Si₃(C_x) layer is also detected. Raman peakshift in Ti₅Si₃(C_x) layer possibly results from residual stress or/and microstructural evolution caused by carbon solution. No evidence indicates Mo participation of interfacial reactions. However, Mo diffusion changes phase distribution of matrix alloy and affects interfacial reaction indirectly. Meanwhile, TEM and Raman results indicate that particles are TiC_x and defective Ti₃AlC₂. Raman features of Ti₃AlC₂ particles differ from that of bulk material, which is attributed to defects. Although Ti₃AlC₂ formation mechanism is ambiguous, it possibly relates to TiC_x formation nearby. Copyright © 2014 John Wiley & Sons, Ltd.     

Noncovalent Functionalization of Single-Walled Carbon Nanotube by Porphyrin: Dispersion of Carbon Nanotubes in Water and Formation of Self-Assembly Donor-Acceptor Nanoensemble

A water-soluble nanoensemble of porphyrin and single-walled carbon nanotubes (SWNTs) was fabricated via electrostatic attraction. The formation of this supramolecular complex was monitored by UV-vis spectra and fluorescence spectra. The donor-acceptor properties of this nanoensemble were characterized by I–V performance of relative photovoltaic device fabricated by layer-by-layer (LBL) technique.     

CO诱导的FeO(111)/Ru(0001)负载Au原子吸附位和电荷的改变

采用密度泛函理论研究了CO气氛对FeO(111)/Ru(0001)负载Au原子吸附位、电荷及其稳定性的影响. 首先考察了FeO(111)单层薄膜在Ru(0001)表面上的界面结构. 研究发现,表面莫尔超晶胞内的HCP区域有最小的Fe-O层间距(rumpling),且Fe和O原子均与衬底Ru形成化学键. Au原子在FeO/Ru(0001)上最稳定的吸附在HCP区域的Fe-bridge位. 其中,Au原子诱导两个Fe原子从O原子层的下面翻转到其上面,形成两个Au-Fe键,且Au带负电. 当把体系暴露在CO气氛下后,CO能诱导Au原子从原来最稳定的Fe-bridge位转移到其邻近的O-top位,伴随着Au的电荷从负变到正,形成非常稳定的Au⁺-CO羰基物. 结果表明,反应气氛对负载金属催化剂的化学状态及其稳定性的影响很大; 同时也强调了反应条件下催化剂原位表征的重要性.     

Electrically induced and thermally erased properties of side-chain liquid crystalline polymer/liquid crystal/chiral dopant composites

The properties of synthesized side-chain liquid crystalline polymer (SCLCP)/liquid crystal (LC)/chiral dopant composites having a chiral nematic (N*) phase at room temperature were investigated by polarized optical microscopy (POM) and a UV/VIS/NIR spectrophotometer. The composite exhibited a planar texture after it was filled into cells under homogeneous boundary conditions and it was transparent. When an electric field was applied to the composite, a focal conic texture was formed and the composite became light scattering. After the electric field was turned off, the light-scattering state remained stable for some time, i.e. the light-scattering state exhibited a memory effect. The focal conic texture changed into the planar texture when the composite was heated and the composite became transparent again. Therefore, the composite had electrically induced and thermally erased properties. The SCLCP had some influence on the memory effect and on the thermo-electro-optical properties of the composite.     

一类Morita Contexts的M-投射左总体维数

我们引进了模的M-投射维数和环的M-左总体维数的概念,采用比较新颖简便的方法,得到了一类Morita Contexts T=R ReeR eRe,e∈R,e2=e和环的M-左总体维数之间的相等关系.