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Bistachybotrysins W-Y (1–3), three new phenylspirodrimane dimers with a 6/7 oxygen heterocycle as the linkage, were isolated from Stachybotrys chartarum CGMCC 3.5365. The structures of 1–3 were elucidated through extensive spectroscopic data analysis, including 1D/2D NMR, HR-ESI-MS, and ECD spectra. Compounds 1 and 3 displayed moderate cytotoxic activity against human tumor cell lines HCT116, Daoy, and HepG2 with IC50 values ranging from 5.9 to 9.8 μM.

Bistachybotrysin K (1), one new phenylspirodrimane dimer with a central 6/7 oxygen heterocycle core, was isolated from the fungus Stachybotrys chartarum CGMCC 3.5365. Its structure was eluc...

Bistachybotrysins D and E (1 and 2), one stereoisomeric pair of phenylspirodrimane dimers, were isolated from Stachybotrys chartarum CGMCC 3.5365. They represent novel phenylspirodrimane dimers with a central [6,5,6]-tricyclic carbon scaffold containing a cyclopentanone core. The structures of 1 and 2 were elucidated through extensive spectroscopic data analysis, and their absolute configurations were characterized by calculated electronic circular dichroism (ECD). Compounds 1 and 2 displayed potent cytotoxic activity against the four human tumor cell lines HCT116, BGC823, Daoy and HepG2 with IC50 values ranging from 6.7 μmol/L to 11.6 μmol/L. Furthermore, a plausible biogenetic pathway for 1 and 2 is proposed.

Bistachybotrysins A–C ( 1 – 3 ), three phenylspirodrimane dimers representing an unusual [6,6,7,6]-tetracyclic skeleton with a central 2,10-dioxabicyclo[4.3.1]decan-7-ol core fused with two phenyl units, were isolated from a fungal strain, Stachybotrys chartarum CGMCC 3.5365. The structures of 1 – 3 were elucidated through extensive spectroscopic data analysis, including Mo 2 (AcO) 4 -induced and calculated electronic circular dichroism (ECD). 1 and 2 exhibited potent cytotoxicity against four human tumor cell lines with IC 50 values in the range of 2.8–7.5 μM. Furthermore, a possible biogenesis for 1 – 3 is proposed.

Seven new phenylspirodrimane derivatives named stachybotrysins A–G (2–8), together with five known compounds (1, 9–12), were isolated from Stachybotrys chartarum CGMCC 3.5365. Stachybotrysin D (5) is the first reported example of a naturally occurring alcoholic O-sulfation of a phenylspirodrimane, and stachybotrysins F and G (7 and 8) are the first examples possessing an isobenzotetrahydrofuran ring with an acetonyl moiety attached. The structures of these compounds were elucidated on the basis of extensive spectroscopic data analysis and by comparison with reported data. The absolute configurations of 1–8 were determined by X-ray single-crystal diffraction, electronic circular dichroism (ECD), and calculated ECD. Compounds 1 and 8 displayed anti-HIV activity with IC50 values of 15.6 and 18.1 μM, respectively, and 2, 7, 9, and 11 showed inhibitory effect on influenza A virus with IC50 values ranging from 12.4 to 18.9 μM.

Bistachybotrysins F-J (1–5), five new phenylspirodrimane dimers with a central cyclopentanone core were isolated from Stachybotrys chartarum CGMCC 3.5365. The structures of 1–5 were elucidated through extensive spectroscopic data analysis, including 1D/2D NMR, HR-MS, and ECD spectra. Compounds 3–5 displayed moderate cytotoxic activity against the cell lines HCT116, NCI-H460, and HepG2 with IC50 values ranging from 9.1 to 12.2 μM, making them promising as lead compounds for drug research and discovery.

Three new phenylspirodrimanes derivatives named stachybotrysins H and I (1 and 2) and stachybotrin E (3), together with one known compound stachybotrylactam (4), were isolated from Stachybotrys chartarum CGMCC 3.5365. Their structures were determined by extensive NMR data and mass spectroscopic analysis. Compounds 1 and 2 showed inhibitory effect towards potassium channel Kv1.3 with IC50 values of 13.4 and 10.9 μM, respectively.

CdS quantum dots(QDs) sensitized TiO2 nanotube arrays photoelectrodes were investigated for their photovoltaic performance of quantum dots-sensitized solar cells. The highly ordered TiO2 nanotube arrays(TNAs) were synthesized on Ti foils by anodic oxidation method. Then CdS quantum dots were deposited onto the TiO2 nanotube arrays by successive ionic layer absorption and reaction(SILAR) method to serve as the sensitizers. Cd(NO3)2 and Na2S were used as the precursor materials of Cd+ and S2− ions, respectively. It is found that the CdS QDs sensitizer may significantly increase the light response of TiO2 nanotube arrays. With increasing CdS QDs deposition cycles, the visible light response increases. Maximum photocurrent was obtained for the QDs that have an absorption peak at about 500 nm. Under AM 1.5 G illuminations(100 mW cm−2), a 4.85 mA/cm2 short circuit current density was achieved, and the maximium energy conversion efficiency of the asprepared CdS QDs-sensitized TNAs solar cells was obtained as high as 0.81 % at five SILAR cycles.

A new photoelectrochemical chiral sensor was developed in this study, which was achieved through the combination of Langmuir–Blodgett and self-assembly techniques to cast a monolayer of chiral metal complex Λ-[Os(phen) 3 ] 2+ onto a single layer TiO 2 film on an indium tin oxide (ITO) substrate. When being applied for photoelectrochemical sensing of binaphthol isomers, the as-prepared hybrid film exhibited a much higher chiral selectivity than the ITO/clay/Λ-[Os(phen) 3 ] 2+ film reported earlier. The experimental detection limit is about 20 μM. The great enhancement is because TiO 2 provides a better charge separation, which facilitates the electron transfer reaction of those excited Os(II) * . For small peptide derivatives of 5-fluorouracil, the ITO/TiO 2 /Λ-[Os(phen) 3 ] 2+ film yielded a chiral selectivity of 1.5.

Hydrolysis and oxidation of formamidine disulfide in acidic medium were investigated using high-performance liquid chromatography (HPLC) and mass spectrometry (MS) at 25 °C. By controlling the slow reaction rate and choosing appropriate mobile phase, HPLC provides the unique advantages over other methods (UV-Vis, chemical separation) in species tracking and kinetic study. In addition to thiourea and formamidine sulfinic acid, two unreported products were also detected in the hydrolysis reaction. Mass spectrometry measurement indicates these two products to be formamidine sulfenic acid and thiocyanogen with mass weights of 92.28 and 116.36, respectively. In the oxidation of formamidine disulfide by hydrogen peroxide, besides thiourea, formamidine sulfenic acid, formamidine sulfinic acid, thiocyanogen and urea, formamidine sulfonic acid and sulfate could be detected. The oxidation reaction was found to be first order in both formamidine disulfide and hydrogen peroxide. The rate constants of hydrolysis and oxidation reactions were determined in the pH range of 1.5–3.0. It was found both rate constants are increased with the increasing of pH. Experimental curves of different species can be effectively simulated via a mechanism scheme for formamidine disulfide oxidation, including hydrolysis equilibrium of formamidine disulfide and irreversible hydrolysis of formamidine sulfenic acid.

NMR and GC/MS spectroscopy of the organic extracts of the oscillatory bromate-1,4-cyclohexanedione reaction illustrate the presence of ring-opening products 5-(dibromomethylene)-2(5H)-furanone, (E)-5,5,5-tribromo-4-oxo-2pentenoic acid, and dibromoacetic acid, particularly at elevated temperatures. The loss of a carbon atom from the six-membered ring after ring opening led to gas formation and such a process became more vigorous at >60 -C, with the direct observation of bubbles in a stirred batch reactor. Gravimetric experiments confirm that the amount of carbon dioxide gas produced increases rapidly with reaction temperature. Parallel experiments suggest that the ring-opening process involves the oxidation of brominated benzoquinones by bromate. Copyright 2010 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this paper.

Kinetics and mechanism of the electrochemical oxidation of thiocyanate on a Pt electrode were investigated by using various electrochemical methods, in which both current and potential oscillations have been observed. Cyclic voltammetry measurements illustrate that the oxidation process consists of two steps. In addition to the oscillatory behavior, the system also exhibits bistability, in which the oxidation could be switched between a high and a low current density states with a temporal potential perturbation. The presence of inert ions with stronger absorption also induces transitions from oscillatory to steady reactions in the thiocyanate system.

In this paper, Al doped B-substituted NiO films were prepared by sol–gel method. The effect of the Al content on the structure of the Al x B 0.15 NiO films were studied with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical and EC properties were examined by cyclic voltammetric (CV) measurements and UV–Vis spectrophotometry, respectively. Al doping could prevent the crystallization of the films, which exhibited much better electrochemical and electrochromic properties than undoped samples. The bleached state absorbance could be significantly lowered when the Al added. EC efficiencies measured at λ = 500 nm of the films with different Al doping content reach ∼30 cm 2 C −1 , with a change in transmittance up to 70%.

Copper indium disulfide (CuInS2) nano-particles have been synthesized by solvothermal method for absorption layer of solar cells. The CuInS2 nano-particles can be adsorbed in pores of TiO2 porous films. The effects of heat-treatment on crystalline structures and sizes of the CuInS2 nano-particles were investigated. Crystalline structures and sizes were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) investigations. Surface morphologies and optical properties were studied by field-emission scanning electron microscope (FESEM) and UV–vis spectra when CuInS2 were absorbed on TiO2 films. The results show that the CuInS2 quantum dots (size is smaller than 10 nm) can be synthesized by solvothermal method at 150 °C. CuInS2 particles sizes increase with the rise of reaction temperature and time. The CuInS2 quantum dots can be adsorbed on TiO2 films well and high-absorptive anodic electrode of solar cells can be prepared. Blue shift of absorption edge was observed as the sizes of CuInS2 quantum dots decreased.

We explored the temperature-dependent dynamics of the electrochemical oxidation of thiourea under potential-control mode and found complex oscillations with one large peak and one small peak per period. Adjusting the temperature caused the relative amplitudes and positions of the two peaks to vary. Experiments showed that there were two distinct oscillatory regimes as a function of the external current, and at some temperatures, three-frequency quasiperiodic oscillations occurred for current densities between the two oscillatory windows. We examined the species present and the component reactions by employing cyclic voltammetry and electrolysis-HPLC-MS in the two oscillatory regimes. Adsorption and desorption of multiple species, including water and chloride, contribute to the rich dynamical phenomena that were observed.

The electrochemical oxidation of sulfide on a polycrystalline platinum electrode was studied under potentiostatic condition when an external resistor is in series with the working electrode. Only two oscillatory regions can be obtained in the absence of the external resistance, but four oscillatory regions, including two new current oscillations, were found in this system by controlling the external resistance. It is demonstrated that three oscillatory regimes, which arise on the positive branch of current-potential curve, can be classified as HN-NDR (Hidden N-shaped Negative Differential Resistance) oscillators. For the first oscillatory region, various transient complex phenomena, which result from the change of the electrode/electrolyte interface by accumulation of adsorbed element sulfur on the electrode, have been observed. The dynamic behavior of NDR (Negative Differential Resistance) oscillations, appearing along with negative branch of polarization curve, can transform from oscillations into bistability with a sufficient large external resistance in series. Two oscillatory regions in high-potential region classified as HN-NDR type oscillations are separated by a saddle-loop bifurcation. They displayed a sequence of bursting oscillations and irregular oscillations, respectively. The electrochemical oxidation of sulfide provides a model system for studying complex dynamics and possible application in sulfur removal.

Mutations in the transcriptional repressor methyl CpG binding protein 2 (MeCP2) are responsible for most cases of Rett Syndrome (RS), a severe neurodevelopmental disorder characterized by developmental regression, minimal speech, seizures, postnatal microcephaly and hand stereotypies. Absence of the maternal copy of ubiquitin protein ligase 3A (UBE3A) results in Angelman syndrome, also a severe developmental disorder that shares some clinical features with RS. As MeCP2 regulates gene expression, this has led to the hypothesis that MeCP2 may regulate UBE3A expression; however, there are conflicting reports regarding the expression of Ube3a in MeCP2 null mutant mice. We have generated a novel MeCP2 mutant knock-in mouse with the mutation R168X, one of the most common mutations in patients with RS. These mice show features similar to RS, including hypoactivity, forelimb stereotypies, breathing irregularities, weight changes, hind limb atrophy, and scoliosis. The male mice experience early death. Analysis of Ube3a mRNA and protein levels in the Mecp2(R168X) male mice showed no significant difference in expression compared to their wild type littermates.

The ferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction, the oxidation of malonic acid by acidic bromate, is the most commonly investigated chemical system for understanding spatial pattern formation. Various oscillatory behaviors were found from such as mixed-mode and simple period-doubling oscillations and chaos on both Pt electrode and Br-ISE at high flow rates to mixed-mode oscillations on Br-ISE only at low flow rates. The complex dynamic behaviors were qualitatively reproduced with a two-cycle coupling model proposed initially by Gyorgyi and Field. This investigation offered a proper medium for studying pattern formation under complex temporal dynamics. In addition, it also shows that complex oscillations and chaos in the BZ reaction can be extended to other bromate-driven nonlinear reaction systems with different metal catalysts.

The electrochemical oxidation of thiosulfate is revealed to have two distinct oscillatory regimes in both linear potential and galvanic voltammograms, where various nonlinear behaviors such as period-2, mixed-mode and quasi-periodic oscillations, and chaos are observed under potentiostatic or galvanostatic conditions. Electrochemical impedance spectroscopy and iR compensation characterization indicate that, depending on the operating conditions, the system could be either a strictly potentiostatic oscillator or an S-shaped negative differential resistance oscillator. Chronoamperometry measurements reveal that the first oscillatory process involves a single-electron transfer, whereas within the second oscillatory regime the average number of electrons transferred is around 3.8. Measurements with capillary electrophoresis and chemical methods illustrate that the oxidation products include S2O6(2-), S4O6(2-), S5O6(2-), S3O6(2-), and SO4(2-).

The electro-oxidation of sulfide on a Pt electrode is found to exhibit both N-NDR (negative differential resistance) and HN-NDR (hidden negative differential resistance) types of oscillations, making it the first system known to be capable of supporting both types of nonlinear instabilities without changing electrolyte compositions. Six distinct oscillation windows are observed when the external current is adjusted as the control parameter. In addition, temperature also exhibits subtle influences on the observed reaction behavior, where varying the temperature from 30.0 °C results in more complicated oscillatory phenomena. Keywords: Electrochemical oscillations, Nonlinear instabilities, Sulfide, Platinum electrodes

The electrochemical oxidation of thiourea on a Pt electrode was found to exhibit both simple and period-doubled oscillations. Measurements of the potentiostatic I/O behavior and impedance spectra suggest that the studied system belongs to the hidden negative differential resistance (HNDR) oscillator. The dependence of complex oscillations on initial compositions of the reaction mixture and temperature has also been characterized, which showed that: (1) lowering the reaction temperature facilitates the occurrence of complex oscillations; (2) the frequency of oscillation increases linearly with respect to the temperature; and (3) hydrochloric acid exhibits stronger influence on the reaction behavior than nitric acid.

An indirect UV detection method based on capillary electrophoresis was developed to separate eleven metal cations completely, including alkali, alkaline earth and transition metal, which are related to evaluate the quality of honey. The background electrolyte contains 15 mmol/L chromophore imidazole, and acetic acid (pH = 3.7), which functioned as pH adjustor and complexing reagent. The selected cations can be completely separated within 8 min under hydrodynamic mode injection with a running voltage of 20 kV at 25°C. Limit of detection, linearity, reproducibility relative standard deviation of migration time and recoveries are in the range of 0.01-0.21 mg/L, 0.06-60.0 mg/L, 2.1-3.4% and 95.4-104.1%, respectively. The applicability of the method is shown by the analysis of honey samples, including a comparison with results of pretreatment and unpretreatment of eight samples. The results demonstrate that the developed method can conveniently be used in routine analysis of honey.

Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. Disturbed glutamate signaling resulting in hypofunction of N-methyl-D-aspartate receptors (NMDAR) has been implicated in the pathophysiology of schizophrenia. Glutamate Carboxypeptidase II (GCP II) hydrolyzes N-acetyl-alpha L-aspartyl-L-glutamate (NAAG) into glutamate and N-acetyl-aspartate. NAAG is a neuropeptide that is an NMDAR antagonist as well as an agonist for the metabotropic glutamate receptor-3 (mGluR3), which inhibits glutamate release. The aggregate effect of NAAG is thus to attenuate NMDAR activation. To manipulate the expression of GCP II, LoxP sites were inserted flanking exons 1 and 2, which were excised by crossing with a Cre-expressing mouse. The mice heterozygous for this deletion showed a 50% reduction in the expression level of protein and functional activity of GCP II in brain samples. Heterozygous mutant crosses did not yield any homozygous null animals at birth or as embryos (N > 200 live births and fetuses). These data are consistent with the previous report that GCP II homozygous mutant mice generated by removing exons 9 and 10 of GCP II gene were embryonically lethal and confirm our hypothesis that GCP II plays an essential role early in embryonic development. Heterozygous mice, however, developed normally to adulthood and exhibited increased locomotor activity, reduced social interaction, and a subtle cognitive deficit in working memory.