Enhanced Degradation of Rh 6G by Zero Valent Iron Loaded on Two Typical Clay Minerals With Different Structures Under Microwave Irradiation

Nanoscale zero valent iron has been a widespread concern in various fields due to its large specific surface area and high reactivity. However, nanoscale zero valent iron (nZVI) is very likely to aggregate and be oxidized, which limit its wide application in industry. Most clay minerals have a large adsorption capacity of cations due to their negative charges and high specific surface areas. In the present work, nZVI was loaded onto two typical clay minerals: kaolinite and sepiolite, to inhibit its oxidation and aggregation. The composites were applied to degrade Rhodamine 6G (Rh 6G) under microwave irradiation. The effects of pH value and microwave power on degradation were studied. The results showed that the removal amount of Rh 6G by nZVI/kaolinite was 110 mg/g in 15 min, while it reached 300 mg/g by nZVI/sepiolite. The difference between these two composites was mostly determined by the structures of these two clay minerals

Sperm parameters and epididymis function in transgenic rats overexpressing the Ca-2-binding protein regucalcin: a hidden role for Ca-2 in sperm maturation?

Sperm undergo maturation acquiring progressive motility and the ability to fertilize oocytes through exposure to the components of the epididymal fluid (EF). Although the establishment of a calcium (Ca-2) gradient along the epididymis has been described, its direct effects on epididymal function remain poorly explored. Regucalcin (RGN) is a Ca-2-binding protein, regulating the activity of Ca-2-channels and Ca-2-ATPase, for which a role in male reproductive function has been suggested. This study aimed at comparing the morphology, assessed by histological analysis, and function of epididymis, by analysis of sperm parameters, antioxidant potential and Ca-2 fluxes, between transgenic rats overexpressing RGN (Tg-RGN) and their wild-type littermates. Tg-RGN animals displayed an altered morphology of epididymis and lower sperm counts and motility. Tissue incubation with Ca-45(2) showed also that epididymis of Tg-RGN displayed a diminished rate of Ca-2-influx, indicating unbalanced Ca-2 concentrations in the epididymal lumen. Sperm viability and the frequency of normal sperm, determined by the one-step eosin-nigrosin staining technique and the Diff-Quik staining method, respectively, were higher in Tg-RGN. Moreover, sperm of Tg-RGN rats showed a diminished incidence of tail defects. Western blot analysis demonstrated the presence of RGN in EF as well as its higher expression in the corpus region. The results presented herein demonstrated the importance of maintaining Ca-2-levels in the epididymal lumen and suggest a role for RGN in sperm maturation. Overall, a new insight into the molecular mechanisms driving epididymal sperm maturation was obtained, which could be relevant to development of better approaches in male infertility treatment and contraception.Portuguese Foundation for Science and Technology (FCT) under Program COMPETE [PEst-C/SAU/UI0709/2011]; FCT; FCT fellowships [SFRH/BD/60945/2009, SRFH/BPD/80451/2011]info:eu-repo/semantics/publishedVersio

Effective Degradation of Rh 6G Using Montmorillonite-Supported Nano Zero-Valent Iron under Microwave Treatment

Nano zero-valent iron has drawn great attention for the degradation of organic dyes due to its high reactivity, large specific surface area, lightweight, and magnetism. However, the aggregation and passivation of iron nanoparticles may prohibit the wide use of it. A new composite material was prepared by loading nano zero-valent iron (nZVI) on montmorillonite (MMT) to overcome the above shortcomings and it was further used for the removal of Rhodamine 6G (Rh 6G) under microwave treatment in the present work. The effects of various parameters, including the initial concentration of Rh 6G, microwave power, and pH value were investigated. The new composite material (nZVI/MMT) showed an excellent degradation ability for removing Rh 6G, and the removal amount reached 500 mg/g within 15 min. The degradation rate reached 0.4365 min−1, significantly higher than most previous reports using other removal methods for Rh 6G

Dual-Responsive [2]Pseudorotaxane On the basis of a pH-Sensitive Pillar[5]arene and Its Application in the Fabrication of Metallosupramolecular Polypseudorotaxane

Metallosupramolecular polymer, an appealing polymeric material, plays important roles in many fields including catalysis, electrochemical devices, conducting materials and so on. As a class of metallosupramolecular polymers, metallosupramolecular polypseudorotaxane has attracted great attention not only because of its wide applications but also due to its facile synthesis which is by metal coordination between metal and macrocycle-based pseudorotaxane. The introducing of stimuli-responsive property into the metallosupramolecular polypseudorotaxane system will enrich their functionality. Herein, a triple stimuli-responsive metallosupramolecular polypseudorotaxane constructed by pillararene-based host–guest interaction and copper coordination. First, a new pH-sensitive pillar[5]­arene host (<b>H</b>) was synthesized. An azastilbenzene derivative, <i>trans</i>- 4,4′-vinylenedipyridine (<i><b>trans</b></i>-<b>G</b>) was chosen as the guest molecule to construct a [2]­pseudorotaxane based on <b>H</b> and <i><b>trans</b></i>-<b>G</b>. The [2]­pseudorotaxane displayed pH- and photo- dual stimuli-responsiveness. Then the [2]­pseudorotaxane was used to construct a pH-, photo- and cyanide-triple stimuli-responsive metallosupramolecular polypseudorotaxane based on Cu­(II) ion coordination

A Low-Distortion 20 GS/s Four-Channel Time-Interleaved Sample-and-Hold Amplifier in 0.18 μm SiGe BiCMOS

This paper presents a 20 GS/s four-channel time-interleaved sample-and-hold amplifier (SHA), which aims to improve the harmonic distortion performance, eliminate the common-mode voltage fall in track-to-hold transition, and solve the difficulty of timing mismatch calibration among different sampling channels. In data path, the harmonic distortion of the track-hold switch is optimized by introducing a distortion-improving resistor into the switched emitter follower. The common-mode voltage fall is eliminated by an inserted delay-regulating resistor. Additionally, broadband data buffers are utilized to further guarantee a wide bandwidth. In clock path, an interpolator-based phase regulator in analog domain is implemented to calibrate the timing mismatch, hence avoiding the large area cost and complicated algorithm in the digital domain. Fabricated in a 0.18 &mu;m SiGe BiCMOS process, the experimental results show that the SHA achieves a bandwidth of 16 GHz and a total harmonic distortion of &minus;39.6 to approximately &minus;51.8 dB with a &minus;3 dBm input. By applying the proposed sampling phase regulator, the timing mismatch can be optimized to satisfy the requirement of 6-bit resolution at a 4 &times; 5 GS/s sampling rate. The proposed SHA shows prominent performance on both bandwidth and linearity, which makes it suitable for ultra-high-speed communication networks

Dual-Responsive [2]Pseudorotaxane On the basis of a pH-Sensitive Pillar[5]arene and Its Application in the Fabrication of Metallosupramolecular Polypseudorotaxane

Metallosupramolecular polymer, an appealing polymeric material, plays important roles in many fields including catalysis, electrochemical devices, conducting materials and so on. As a class of metallosupramolecular polymers, metallosupramolecular polypseudorotaxane has attracted great attention not only because of its wide applications but also due to its facile synthesis which is by metal coordination between metal and macrocycle-based pseudorotaxane. The introducing of stimuli-responsive property into the metallosupramolecular polypseudorotaxane system will enrich their functionality. Herein, a triple stimuli-responsive metallosupramolecular polypseudorotaxane constructed by pillararene-based host–guest interaction and copper coordination. First, a new pH-sensitive pillar[5]­arene host (<b>H</b>) was synthesized. An azastilbenzene derivative, <i>trans</i>- 4,4′-vinylenedipyridine (<i><b>trans</b></i>-<b>G</b>) was chosen as the guest molecule to construct a [2]­pseudorotaxane based on <b>H</b> and <i><b>trans</b></i>-<b>G</b>. The [2]­pseudorotaxane displayed pH- and photo- dual stimuli-responsiveness. Then the [2]­pseudorotaxane was used to construct a pH-, photo- and cyanide-triple stimuli-responsive metallosupramolecular polypseudorotaxane based on Cu­(II) ion coordination

Dual-Responsive [2]Pseudorotaxane On the basis of a pH-Sensitive Pillar[5]arene and Its Application in the Fabrication of Metallosupramolecular Polypseudorotaxane

Metallosupramolecular polymer, an appealing polymeric material, plays important roles in many fields including catalysis, electrochemical devices, conducting materials and so on. As a class of metallosupramolecular polymers, metallosupramolecular polypseudorotaxane has attracted great attention not only because of its wide applications but also due to its facile synthesis which is by metal coordination between metal and macrocycle-based pseudorotaxane. The introducing of stimuli-responsive property into the metallosupramolecular polypseudorotaxane system will enrich their functionality. Herein, a triple stimuli-responsive metallosupramolecular polypseudorotaxane constructed by pillararene-based host–guest interaction and copper coordination. First, a new pH-sensitive pillar[5]­arene host (<b>H</b>) was synthesized. An azastilbenzene derivative, <i>trans</i>- 4,4′-vinylenedipyridine (<i><b>trans</b></i>-<b>G</b>) was chosen as the guest molecule to construct a [2]­pseudorotaxane based on <b>H</b> and <i><b>trans</b></i>-<b>G</b>. The [2]­pseudorotaxane displayed pH- and photo- dual stimuli-responsiveness. Then the [2]­pseudorotaxane was used to construct a pH-, photo- and cyanide-triple stimuli-responsive metallosupramolecular polypseudorotaxane based on Cu­(II) ion coordination

A method for three-dimensional quantitative observation of the microstructure of biological samples

Contemporary biology has developed into the era of cell biology and molecular biology, and people try to study the mechanism of all kinds of biological phenomena at the microcosmic level now. Accurate description of the microstructure of biological samples is exigent need from many biomedical experiments. This paper introduces a method for 3-dimensional quantitative observation on the microstructure of vital biological samples based on two photon laser scanning microscopy (TPLSM). TPLSM is a novel kind of fluorescence microscopy, which has excellence in its low optical damage, high resolution, deep penetration depth and suitability for 3-dimensional (3D) imaging. Fluorescent stained samples were observed by TPLSM, and afterward the original shapes of them were obtained through 3D image reconstruction. The spatial distribution of all objects in samples as well as their volumes could be derived by image segmentation and mathematic calculation. Thus the 3-dimensionally and quantitatively depicted microstructure of the samples was finally derived. We applied this method to quantitative analysis of the spatial distribution of chromosomes in meiotic mouse oocytes at metaphase, and wonderful results came out last. ? 2009 SPIE.EI

α-Ketoglutarate prevents hyperlipidemia-induced fatty liver mitochondrial dysfunction and oxidative stress by activating the AMPK-pgc-1α/Nrf2 pathway

α-Ketoglutarate (AKG), a crucial intermediate in the tricarboxylic acid cycle, has been demonstrated to mitigate hyperlipidemia-induced dyslipidemia and endothelial damage. While hyperlipidemia stands as a major trigger for non-alcoholic fatty liver disease, the protection of AKG on hyperlipidemia-induced hepatic metabolic disorders remains underexplored. This study aims to investigate the potential protective effects and mechanisms of AKG against hepatic lipid metabolic disorders caused by acute hyperlipidemia. Our observations indicate that AKG effectively alleviates hepatic lipid accumulation, mitochondrial dysfunction, and loss of redox homeostasis in P407-induced hyperlipidemia mice, as well as in palmitate-injured HepG2 cells and primary hepatocytes. Mechanistic insights reveal that the preventive effects are mediated by activating the AMPK-PGC-1α/Nrf2 pathway. In conclusion, our findings shed light on the role and mechanism of AKG in ameliorating abnormal lipid metabolic disorders in hyperlipidemia-induced fatty liver, suggesting that AKG, an endogenous mitochondrial nutrient, holds promising potential for addressing hyperlipidemia-induced fatty liver conditions