Effect of adding artificial reverberation to speech-like masking sound

Time-reversed speech has been known to effectively mask information for speech privacy applications. However, the annoyance and distraction caused by the time-reversed speech-like masking sound is higher than other masking sound. This study investigates the effects of adding artificial reverberation to the time-reversed speech. Subjective listening tests have been conducted to measure the intelligibility of target speech, annoyance and distraction caused by the masking sound. The experimental results suggest that adding artificial reverberation to a speech-like masking sound has a significant effect to reduce the annoyance level while maintaining the masking effectiveness of the original masking sound. A trend was also observed that the addition of artificial reverberation could reduce the level of distraction caused by the masking sound.     

Fullerene‐Structural Carbon‐Based Dots from C60 Molecules and their Optical Properties

Fullerene‐structural carbon‐based dots (f‐CDs) are synthesized for the first time by chemically oxidizing fullerene molecules (C₆₀) using concentrated HNO₃. The lateral sizes of the f‐CDs distribute in the range of 7–20 nm, and the heights mainly range from 0.4 to 1.3 nm with an average value of 0.7 nm. The presence of massive pentagonal carbon units makes the f‐CDs different from most of graphitic‐CDs in structure and morphology. The f‐CDs exhibit unique luminescent properties such as photoluminescence (PL) and electrochemiluminescence. Based on the investigation of the UV–vis absorption and luminescent properties, a novel and reasonable model is proposed for the PL mechanism of f‐CDs. Furthermore, the obtained f‐CDs show low cytotoxicity and have potential application in cell imaging.     

Insights into the synergy of zero-valent iron and copper oxide in persulfate oxidation of Orange G solutions

The degradation of Orange G (OG) by persulfate (PS, S₂O₈ ^2?) activated with dual catalysts that combined zero-valent iron (ZVI) and copper oxide (CuO) was investigated through batch experiments. Effects of pH, initial OG concentration, persulfate dosages, and dosages of dual catalysts on OG degradation were also examined. Higher persulfate concentration and catalysts dosages resulted in higher OG degrading rates. The OG degradation was higher under acidic conditions (pH 3.0 and 5.0) when compared to alkaline conditions. The constituents and the morphology of the catalysts coating before and after reaction were also investigated with X-ray diffraction and scanning electron microscopy. Radical mechanism was studied and three radical scavengers [methanol (MA), tert-butanol (TBA), phenol] were used to determine the type of major active species taking part in the degradation of OG. It was assumed that the \({\text{SO}}_{4}^{ \cdot - }\) or \({\text{HO}} \cdot\) played a major role in the OG degradation. In conclusion, the ZVI/CuO/PS system is a good candidate for use in detoxifying water contaminants.     

Syntheses,Structures, and Properties of Two Dicyanamide‐Bridged Polymers with a Schiff‐base Ligand

The dicyanamide‐bridged polymers with Schiff‐base ligand, [CoNaL(dca)]_n ( 1 ) and [Mn₂L(dca)₂]_n ( 2 ) [H₂L = bis(3‐methoxysalicylidene)benzene‐1,2‐diamine, dca = dicyanamide] were synthesized and characterized by elemental analyses, IR spectrroscopy and single‐crystal X‐ray diffraction. The solid‐state structures reveal that polymer 1 has double dca bridged loop‐like 1D chains, in which the heterodinuclear Co²⁺‐Na⁺ units (LCoNa) are bridged by dca with coordination mode μ_1,3,5. In polymer 2 , homodinuclear Mn²⁺‐Mn²⁺(LMnMn) units are linked by dca in μ_1,5‐bridging mode to form 2D planes. Magnetic susceptibility studies on 2 reveals antiferromagnetic coupling interactions between the adjacent Mn²⁺ ions in the LMnMn unit.     

Environment‐sensitive Fluorescent Turn‐on Chemical Probe for the Specific Detection of O‐Methylguanine‐DNA Methyltransferase (MGMT) in Living Cells

MGMT protein, which has been associated with resistance to antitumor alkylation drugs for many patients, is a very useful prognostic marker to provide a guide for therapeutic decisions. Considering the large number of cellular samples that have to be handled daily at the hospitals, it is thus important to develop a rapid and simple analytical method to distinguish MGMT activity in different types of cells. In this paper, we describe a MGMT‐activated fluorescence turn‐on probe for the rapid no‐wash imaging of MGMT in living cells. The probe consists of a specific MGMT suicide pseudosubstrate, O⁶‐benzyl‐guanine and an environment‐sensitive fluorophore, SBD. In the presence of MGMT, the enzyme transfers SBD to the protein active site where the hydrophobic surrounding causes the fluorophore to exhibit more than 50‐fold fluorescence enhancement. With this probe, bright fluorescence was observed for MGMT‐positive, Hela S3 and MCF‐7 cells, while MGMT‐deficient CHO cells displayed no fluorescence. We believe that this fluorescence activation probe design can also be extended to detect other transferases, for which there are still no effective methods to image them in living cells.     

Recent advances in phenothiazine-based dyes for dye-sensitized solar cells

Dye-sensitized solar cells(DSSCs) have attracted significant attention as alternatives to conventional silicon-based solar cells owing to their low-cost production,facile fabrication,excellent stability and high power conversion efficiency(PCE).The dye molecule is one of the key components in DSSCs since it significant influence on the PCE,charge separation,light-harvesting,as well as the device stability.Among various dyes,easily tunable phenothiazine-based dyes hold a large proportion and achieve impressive photovoltaic performances.This class of dyes not only has superiorly non-planar butterfly structure but also possesses excellent electron donating ability and large π conjugated system.This review summarized recent developments in the phenothiazine dyes,including small molecule phenothiazine dyes,polymer phenothiazine dyes and phenothiazine dyes for co-sensitization,especially focused on the developments and design concepts of small molecule phenothiazine dyes,as well as the correlation between molecular structures and the photovoltaic performances.     

Fast and effective low‐temperature freezing extraction technique to determine organotin compounds in edible vegetable oil

Most organotin compounds that have been widely used in food packaging materials and production process show serious toxicity effects to human health. In this study, a simple and low‐cost method based on high‐performance liquid chromatography with inductively coupled plasma mass spectrometry for the simultaneous determination of four organotins in edible vegetable oil samples was developed. Four organotins including dibutyltin dichloride, tributyltin chloride, diphenyltin dichloride, and triphenyltin chloride were simultaneously extracted with methanol using the low‐temperature precipitation process. After being concentrated, the extracts were purified by matrix solid‐phase dispersion using graphitized carbon black. The experimental parameters such as extraction solvent and clean‐up material were optimized. To evaluate the accuracy of the new method, the recoveries were investigated. In addition, a liquid chromatography with tandem mass spectrometry method was also proposed for comparison. The procedures of extracting and purifying samples for the analysis were simple and easy to perform batch operations, also showed good efficiency with lower relative standard deviation. The limits of detection of the four organotins were 0.28–0.59 μg/L, and the limits of quantification of the four organotins were 0.93–1.8 μg/L, respectively. The proposed method was successfully applied to the simultaneous analysis of the four organotins in edible vegetable oil. Some analytes were detected at the level of 2.5–28.8 μg/kg.