Polymer Microspheres Copolymerized with Deep Red Fluorescent Molecules as a Label for Lateral Flow Immunochromatography.

The development of fluorescently labeled microspheres is a critical aspect of advancing the technology of lateral flow immunochromatography (LFIA) for biological detection. Nevertheless, potential interference posed by the background fluorescence originating from the nitrocellulose (NC) membrane would significantly impact the sensitivity and accuracy of microsphere-based detection in LFIA. In this work, an attempt was made to extend the π-conjugated system and asymmetric structure of rhodamine fluorophore, resulting in the synthesis of dye molecules (RB2) incorporating double bonds, which can reach an absolute photoluminescence quantum yield (PLQY) of 30.01% in EtOH. Subsequently, carboxyl group functionalized fluorescent microspheres were prepared in a two-step copolymerization via soap-free emulsion polymerization. The obtained microspheres were characterized by scanning electron microscopy, transmission electron microscopy, DLS, Fourier transform infrared spectroscopy, ultraviolet spectrophotometry, and fluorescence spectrophotometry. The results showed that RB2 was successfully copolymerized into the microspheres, and the resulting microspheres had good dispersion and stability with high red fluorescence intensity (λabs ∼ 610 nm, λem ∼ 660 nm). Utilizing these microspheres, the resulting lateral flow immunoassay was successfully found to detect SARS-CoV-2 N protein with a detection limit of 2.5 pg/mL and the linear concentration spanning from 2.5 pg/mL to 10 ng/mL. The results confirm the effectiveness of the synthetic fluorescent microspheres as the label for LFIA.

New evidence of the Hoyle-like structure in 16O.

An experiment of 12C(16O,16O → 4α)12C was performed at a beam energy of 96 MeV. A large number of 4-α events were recorded in coincidence and with full particle identification (PID). This was made possible by employing a series of silicon-strip-based telescopes that provided excellent position and energy resolutions. Four narrow resonances just above the 15.1 MeV state were firmly identified in the α + 12C(7.65 MeV; Hoyle state) decay channel. Combined with the theoretical predictions, these resonant states provide new evidence for the predicted possible Hoyle-like structure in 16O above the 4-α separation threshold. Some very high-lying 4-α resonant states have also been observed and need to be further investigated.

Relationship between oxide identity and electrocatalytic activity of platinum for ethanol electrooxidation in perchlorate acidic solution.

Water and its dissociated species at the solid‒liquid interface play critical roles in catalytic science; e.g., functions of oxygen species from water dissociation are gradually being recognized. Herein, the relationship between oxide identity (PtOHads, PtOads, and PtO2) and electrocatalytic activity of platinum for ethanol electrooxidation was obtained in perchlorate acidic solution over a wide potential range with an upper potential of 1.5 V (reversible hydrogen electrode, RHE). PtOHads and α-PtO2, rather than PtOads, act as catalytic centers promoting ethanol electrooxidation. This relationship was corroborated on Pt(111), Pt(110), and Pt(100) electrodes, respectively. A reaction mechanism of ethanol electrooxidation was developed with DFT calculations, in which platinum oxides-mediated dehydrogenation and hydrated reaction intermediate, geminal diol, can perfectly explain experimental results, including pH dependence of product selectivity and more active α-PtO2 than PtOHads. This work can be generalized to the oxidation of other substances on other metal/alloy electrodes in energy conversion and electrochemical syntheses.

Exploring the formation mechanism of fine particles in an ex-heavily polluted Northwestern city, China.

Fine particle pollution is still a severe issue in the northwestern region of China where the formation mechanism of which remains ambiguous due to the limited studies there. In this study, a comprehensive study on the chemical composition and sources of PM2.5 at an ex-heavily polluted northwestern city was conducted, based on filter sampling data obtained from three consecutive winter campaigns during 2020-2022. The average PM2.5 during the three winter campaigns were 170.9 ± 66.4, 249.0 ± 75.7, and 200.9 ± 47.6 µg/m3, respectively, with the daily maximum value of PM2.5 exceeds 400 µg/m3 under stagnant meteorological conditions charactered by high relative humidity (>60 %) and low wind speed (<1 m/s). The major chemical components in PM2.5 were found to be inorganic aerosol (55.2 %) that mainly constituted by sulfate (24.2 %), and mineral dust (14.9 %); while the carbonous species contributed a minor fraction (∼13 %). In addition, (NH4)2SO4 and NH4NO3 were the dominate contributors to appearance of low visibility (<3 km) which together accounting for over 85 % of light extinction coefficient (bext) during heavy polluted period. Source appointment of fine particles was then conducted by applying the positive matrix factorization method, and the primary sources were resolved to be coal combustion (27.7 %) and biomass burning (18.6 %), followed by industrial dust (16.2 %), residential combustion (15.3 %), traffic emissions (11.9 %) and dust aerosol (10.4 %). To explore the potential formation mechanism of fine particle pollution, the chemical evolution pattern combined with gaseous pollutants and meteorological parameters were further analyzed, which refine the important role of primary emissions in the forming of high sulfate aerosol loading, while secondary formation was largely suppressed during the winter period that totally different from those reported in the developed regions of China, thus indicating more effort should be paid on the reduction of primary particles emissions in the northwestern cities than on its gaseous percussors.

Formation of α clusters in dilute neutron-rich matter.

The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster-knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.

A novel index for assessing the water quality of urban landscape lakes based on water transparency.

Assessment of the aesthetic and recreational value of urban landscape lakes (ULLs) is often required but there has not been a water quality index specifically applicable for such a purpose. Under a consideration that water transparency in terms of Secchi Depth (SD), to a large extent, determines the landscape effect, a study was conducted to identify the major parameters that strongly influence SD and to develop a novel water quality index. By theoretical analyses, it was found that SD is mainly influenced by the contents of chlorophyll a, inorganic suspended solids and organic detritus in water, which collectively relate to eight independent water quality, hydraulic, and environmental parameters, including SS, DO, COD, NH4+-N, NO3--N, TP, HRT, and water temperature T. A composite index was then proposed in the form of WQIULL = ∏i=1nqiwi (n = 8). Using the data of field survey of 166 ULLs in China, the cumulative probability distribution curve of each sub-index qi was characterized. Sensitive analysis was conducted for the determination of the sub-index weight (wi) for each qi under the consideration of two typical scenarios of ULL replenishment by stream water (traditional source) and reclaimed water (alternative source) regarding the variation of parameter on SD. With all wi (i = 1 to 8) thus determined, WQIULL was calculated for each of the ULLs surveyed. All the calculated values of WQIULL showed a good correlative relationship with the SD values practically measured (R2 = 0.8948), indicating that the novel water quality index developed could effectively indicate the satisfactory degree of the lake water quality in terms of water landscape. Further by comparing the dimensionless WQIULL (ranging between 0 and 100) with the practically acceptable SD based on experiences in China, the method for classification of ULLs by WQIULL calculation was formulated.

3D Porous Self-Standing Sb Foam Anode with a Conformal Indium Layer for Enhanced Sodium Storage.

Antimony (Sb) has been considered as a promising anode for sodium-ion batteries (SIBs) because of its high theoretical capacity and moderate working potential but suffers from the dramatic volume variations (∼250%), an unstable electrode/electrolyte interphase, active material exfoliation, and a continuously increased interphase impedance upon sodiation and desodiation processes. To address these issues, we report a unique three-dimensional (3D) porous self-standing foam electrode built from core-shelled Sb@In2O3 nanostructures via a continuous electrodepositing strategy coupled with surface chemical passivation. Such a hierarchical structure possesses a robust framework with rich voids and a dense protection layer (In2O3), which allow Sb nanoparticles to well accommodate their mechanical strain for efficiently avoiding electrode cracks and pulverization with a stable electrode/electrolyte interphase upon sodiation/desodiation processes. When evaluated as an anode for SIBs, the prepared nanoarchitectures exhibit a high first reversible capacity (641.3 mA h g-1) and good cyclability (456.5 mA h g-1 after 300 cycles at 300 mA g-1), along with superior high rate capacity (348.9 mA h g-1 even at 20 A g-1) with a first Coulomb efficiency as high as 85.3%. This work could offer an efficient approach to improve alloying-based anode materials for promoting their practical applications.

Synthesis, characterization and corrosion inhibition behavior of 2-aminofluorene bis-Schiff bases in circulating cooling water.

In this work, two new bis-Schiff bases, namely 2-bromoisophthalaldehyde-2-aminofluorene (M1) and glutaraldehyde 2-aminofluorene (M2), were synthesized, and their structures were characterized and confirmed by infrared spectroscopy, Fourier transform mass spectrometry and UV-visible spectroscopy. Their corrosion inhibition performance on carbon steel in simulated circulating cooling water was investigated by weight loss measurements and electrochemical measurements. The potentiodynamic polarization curves confirmed that two bis-Schiff bases are anode-type inhibitors; electrochemical impedance spectroscopy tests showed that M1 and M2 possess the best inhibition efficiencies of 96.25% and 99.15% at the optimal concentration of 2.50 mmol L-1, respectively. The weight loss results showed that M1 and M2 exhibit maximum η w values of 92.62% and 96.31%, respectively. Scanning electron microscopy showed that the inhibitors inhibited carbon steel corrosion. The adsorption isotherm measurements indicated that the two inhibitors exhibited physicochemisorption mechanisms and followed Langmuir adsorption isotherms. The relationships between the molecular structure and inhibition behavior of the inhibitors were explored by density functional theory, frontier molecular orbital studies, and Fukui index analysis, which affirmed that M2 possesses higher corrosion inhibition efficiency than M1.

Current status and characteristics of urban landscape lakes in China.

Urban landscape lakes (ULLs) are important environmental elements in most cities. In order to understand the current situation of ULLs in China and formulate proper strategies to improve their landscape quality to meet public desire for water-front enjoyment, a study was conducted of 189 ULLs widely distributed in 26 provinces of China, based on existing data and field surveys. These ULLs were firstly categorized according to their topographic features, climatic zones, and water replenishment sources. Lake water quality was evaluated considering both single factors and a comprehensive pollution index (CPI). Results show that if the Chinese Surface Water Quality Standard was used as the sole criteria, about 60% of the ULLs investigated could not meet the lowest requirement. Excessive total nitrogen (TN) concentration was the most limiting factor especially when reclaimed water was the replenishment source. The differences in topographic and climatic conditions to a certain extent affected the availability of replenishment water sources but no significant correlation was identified with the single water quality factors or CPI. However, when public satisfaction was introduced in the evaluation of the ULLs' landscape effect, it was found that the water transparency in terms of Secchi Depth (SD) correlated well with people's appreciation of water landscape.

Novel ternary transition metal oxide solid solution: mesoporous Ni-Mn-Co-O nanowire arrays as an integrated anode for high-power lithium-ion batteries.

Electrochemical performances of lithium-ion batteries depend strongly on the micro-nanostructures of active materials as well as electrode configurations. A reasonable design of both active materials and electrode configuration is of great importance to improving the electrochemical properties of the batteries. Here, we present the preparation and electrochemical properties of mesoporous Ni-Mn-Co-O oxide (NMCO) nanowire arrays (NWAs) directly grown on Cu substrates, which can be used as an integrated electrode for lithium-ion batteries. The electrochemical measurements show that the NMCO/Cu NWA integrated electrodes without binder exhibit enhanced cycling stability and high specific capacity compared with the NMCO nanowire electrode prepared by a conventional coating process. In addition, the NMCO/Cu-foam NWA integrated electrode constructed from porous copper exhibits outstanding cycle stability and rate capability compared with the NMCO/Cu-foil NWA integrated electrode based on a copper foil collector.

Influence of intrinsic decoherence on tripartite entanglement and bipartite fidelity of polar molecules in pendular states.

An array of ultracold polar molecules trapped in an external electric field is regarded as a promising carrier of quantum information. Under the action of this field, molecules are compelled to undergo pendular oscillations by the Stark effect. Particular attention has been paid to the influence of intrinsic decoherence on the model of linear polar molecular pendular states, thereby we evaluate the tripartite entanglement with negativity, as well as fidelity of bipartite quantum systems for input and output signals using electric dipole moments of polar molecules as qubits. According to this study, we consider three typical initial states for both systems, respectively, and investigate the temporal evolution with variable values of the external field intensity, the intrinsic decoherence factor, and the dipole-dipole interaction. Thus, we demonstrate the sound selection of these three main parameters to obtain the best entanglement degree and fidelity.

Double shelled hollow nanospheres with dual noble metal nanoparticle encapsulation for enhanced catalytic application.

We report the design and realization of double shelled @CeO2/M@M/TiO2 (M = Au and/or Pd) nanospheres with dual noble metal nanoparticles encapsulated in metal oxide shells via a layer-by-layer deposition process followed by an alkali etching method. The resulting nanospheres possess uniform sizes, variable shell components and thicknesses, adjustable noble metal nanoparticles encapsulated, regulable chamber spaces between the two shells, and good structural stability, which can be used as unique microreactors with extremely high catalytic activity and stability in the Suzuki-Miyaura coupling reaction, benzyl aerobic alcohol oxidation, and 4-nitrophenol reduction reaction due to their structural features with multiple interactions and strong synergistic effects between the noble metal nanoparticles and metal oxide shells, and less depletion of catalytic active species. The designed double shelled hollow @CeO2/M@M/TiO2 nanocatalysts can be used as novel catalyst systems with highly efficient catalytic performance for various catalytic reactions depending on their shell components and noble metal nanoparticles encapsulated. The synthetic strategy provides a new methodology to design high-performance and multifunctional nanocatalysts.

The synthesis of newly modified CdTe quantum dots and their application for improvement of latent fingerprint detection.

Motivated by the urgent demand for the detection of latent fingerprints using fluorescence-based nanotechnology, this work was devoted to developing a simple synthetic approach to obtain positively charged CdTe QDs with enhanced fluorescence and affinity for the improvement of latent fingerprint detection. Through this synthetic method, the positively charged CdTe-COONH(3)NH(3)(+) QDs were successfully achieved by using hydrazine hydrate as both the surface stabilizer and pH adjuster during the preparation process. In comparison to the negatively charged CdTe-COO(-) QDs prepared by using sodium hydroxide as the pH adjuster, the CdTe-COONH(3)NH(3)(+) QDs showed enhanced fluorescence. The effectiveness of CdTe-COO(-) and CdTe-COONH(3)NH(3)(+) QDs for detection of latent fingerprints present on a large variety of smooth objects was systematically and comparatively studied. The results indicate that the detection of latent fingerprints by using CdTe-COONH(3)NH(3)(+) QDs as fluorescent labeling marks was greatly enhanced, and more characteristic finger ridge details were detected and identified due to their enhanced affinity with latent fingerprints, in comparison to the detection by using CdTe-COO(-) QDs as fluorescent labeling marks. The CdTe-COONH(3)NH(3)(+) QDs show superior detection capability than the CdTe-COO(-) QDs, which greatly improves the applicability of CdTe QDs for practical application in latent fingerprint detection.