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Information on the effects of pollutants in sediments at an ecosystem level to validate current and proposed risk-assessment procedures is scarce. The most frequent criticism of these procedures is that responses of surrogate species in the laboratory are not representative of responses of natural populations. A tiered approach using both laboratory and microcosm exposures (96-h and 21-d laboratory bioassays and a 3-mo field microcosm) was conducted to compare the impacts of sediment-spiked cadmium on the mortality, development, and abundance of Chironomidae larvae. The 96-h and 21-d lethal concentrations of sediment-spiked Cd to 50% of the species Chironomus riparius were estimated to be 201.07 and 172.66 mg/kg, respectively. In the 21-d laboratory bioassay, the endpoints, including the development rate and emergence ratio, were compared, and the lowest-observed-effect concentration (LOEC) values were 325.8 and 10.7 mg/kg, respectively. The abundance, richness, and biomass of field-collected larvae were compared among the different treatments in the field microcosm, and it was found that the order of sensitivities using different endpoints was biomass (2.6/5.2 mg/kg of no-observed-effect concentration/LOEC) > diversity (10.7/21.2 mg/kg) > abundance (41.2/82.7 mg/kg). The toxicity values based on lethal/sublethal changes in the laboratory bioassays might not fully protect field organisms against damage from chemicals, such as Cd, unless an assessment factor of 5 is used. These findings highlight the need to conduct field validation of criteria/guidelines before they are introduced to protect organisms/ecosystems in the field and provide a preliminary template for future field validation of criteria elsewhere. Environ Toxicol Chem 2021;40:2450-2462. © 2021 SETAC.

Nitric oxide (NO), as a bioeffector to improve chemosensitivity by reversing multidrug resistance (MDR), is highly attractive for developing combinational delivery systems to deal with MDR tumors, while it is highly challenged by the stability and controlled release of NO during the pathway. Here we design and synthesize a cyclic nitrate trimethylene carbonate monomer (NTC), followed by ring-opening polymerization to prepare amphiphilic biodegradable polycarbonate-based copolymers as polymeric NO donors with tailored contents. The copolymer with desirable molecular weight is readily self-assembled to biodegradable micelles (NO-M) with a uniform size of 130 nm for highly stabilizing NO donors at the physiological conditions, while triggered NO release from micelles is performed at the intracellular reduction conditions. More importantly, NO-M shows superior inhibition of P-gP expression to enhance the chemosensitivity of multidrug-resistant MCF7 cells (MCF7/DOX

Objective: We aimed to determine whether beryllium toxicity was associated with mitochondria apoptosis pathway in SD rats. Methods: Thirty-two SD rats were given an intratracheal instillation dose ...

The therapeutic potential of nitric oxide (NO) has been highly attractive to tumor treatment, especially for surmounting the multidrug resistance (MDR) of cancer. However, the NO-involved therapy remains extremely challenging because of the difficulty to simultaneously control the NO release rate and real-time concentration. Herein, we construct NO-containing polymersomes with high amount of NO donors inherently grown on the polymer chains to keep the stability. These polymersomes can be simultaneously loaded with photosensitizer of IR780 iodide on the membrane layer and chemotherapeutic of DOX·HCl in the lumen. NO release can be triggered by the reduction conditions, and further accelerated by remote NIR irradiation due to the increased local temperature. The instantaneous NO release with high concentration significantly inhibits the P-gp expression and sensitize the chemotherapy, thus overcoming the tumor MDR and improving the anti-tumor activity. Meanwhile, DOX·HCl release is highly promoted at the intracellular conditions because of the cleavage of acid-labile cis-aconitic amide at endo/lysosomal pH, and the improved hydrophilicity of the membrane layer after NO release. The in vivo results show that the single intravenous injection of polymersome formulation companying with NIR irradiation exerts multi-modal therapies of chemotherapy, PTT/PDT, and NO-therapy on the MCF-7/R tumor models, showing superior and combinational treatment efficacy with the complete eradication of tumors and few side effects.

A ratiometric two-photon probe was designed to visualize HClO levels in tissues, revealing the generation of HClO in the wound-repairing process of mice for the first time., HClO plays crucial roles in a wide range of biological and pathological processes. Recent studies have revealed that the generation of HClO has close links with the wound healing process. It's thus meaningful to develop a reliable method for monitoring HClO in wounded tissues. Toward this purpose, we herein report a rationally designed quinolone-based ratiometric two-photon fluorescent probe, QClO, for HClO. The probe QClO rapidly displays a drop in blue emission and an increase of green emission in response to HClO due to the oxidation of oxathiolane. The fluorescence intensity ratio (green/blue) can serve as the ratiometric detection signal for HClO with high sensitivity. After confirming its excellent sensing performance in vitro, the probe was validated by detecting exogenous and endogenous HClO in living cells. The probe was capable of monitoring HClO in situ in the wounded tissues of mice by two-photon microscopy, which demonstrated the production profile of HClO during the wound-healing process. This work affords a simple and reliable tool for the detection and imaging of HClO, which promises to find more applications in HClO-related biological and pathological studies.

Due to their different structures and virtually unlimited raw material source, organic materials could triumph over many inorganic compounds as electrodes. However, most organic materials suffer the weaknesses of poor electron conducting and being soluble in electrolytes, which leads to low capacities and short lifetimes of batteries. In order to address these weaknesses, we present a readily scale-up-able process to polymerize N-heterotriangulene triketone, resulting in an essentially insoluble, two-dimensional conjugated polymer PHTA, showing a layered morphology with an interlayer spacing of 3.53 A. Benefiting from the polycyclic aromatic hydrocarbonic features, PHTA is insoluble in electrolytes and has high electrical conductivities (2.33 × 10−2 S cm−1). In LIBs, the PHTA electrode reveals a specific capacity of 380 mAh g−1 with an average attenuation rate of 0.026%. These results indicate PHTA to be a superior candidate and open a seminal future for N-heterotriangulene polymers for energy storage.

An N-nitrosation reactivity-based two-photon fluorescent probe for the specific detection of NO was rationally designed, prepared, and applied in the in situ detection of nitric oxide in ischemia reperfusion injury mouse model under two-photon microscopy for the first time., In situ fluorescence imaging of nitric oxide (NO) is a powerful tool for studying the critical roles of NO in biological events. However, the selective imaging of NO is still a challenge because most currently available fluorescent probes rely on the o-phenylenediamine (OPD) recognition site, which reacts with both NO and some abundant reactive carbonyl species (RCS) (such as dehydroascorbic acid and methylglyoxal) and some reactive oxygen/nitrogen species (ROS/RNS). To address this problem, a new fluorescent probe, NCNO, based on the N-nitrosation of aromatic secondary amine was designed to bypass the RCS, ROS, and RNS interference. As was expected, the probe NCNO could recognize NO with pronounced selectivity and sensitivity among ROS, RNS, and RCS. The probe was validated by detecting NO in live cells and deep tissues owing to its two-photon excitation and red-light emission. It was, hence, applied to monitor NO in ischemia reperfusion injury (IRI) in mice kidneys by two-photon microscopy for the first time, and the results vividly revealed the profile of NO generation in situ during the renal IRI process.

Tacrolimus, also known as FK506, is a first-line drug for the topical treatment of immune-mediated inflammatory anterior ocular diseases (IIAODs). However, due to its limited water solubility, hydrophobic nature and relatively high molecular weight, topical application of FK506 features poor bioavailability. Numbers of formulations have been attempted to enhance the erratic bioavailability of FK506 through various techniques. But until now, none of them could satisfy the clinical needs completely. Here, a novel formulation of FK506, FK506-loaded cationic nanoemulsions (FK506 CNE), was developed to prolong the precorneal residence time of FK506, thereby enhancing the bioavailability of FK506 for IIAODs therapy. FK506 CNE was prepared by high-pressure homogenization, and its composition was screened and optimized by single-factor experiments. The FK506 CNE showed spherical morphology with a mean diameter of 178.8 ± 2.7 nm and a zeta potential of +25.6 ± 0.6 mV. Results from in vivo gamma scintigraphy studies proved that the precorneal residence time of FK506 CNE was significantly increased, compared with FK506-loaded neutral nanoemulsions (FK506 NE) and saline. The data of aqueous humor pharmacokinetic study in rabbits showed that the relative bioavailability of FK506 CNE was 1.68-fold and 1.77-fold of FK506 NE and the marketed FK506 eye drops (Talymus®), respectively. Finally, hematoxylin and eosin staining images and in vitro cytotoxicity data confirmed the safety of the FK506 CNE. Taking all these into consideration, we propose that FK506 CNE is a promising topical ophthalmic nanoformulation for the management of IIAODs.

Heat stress during Brassica napus seed filling severely impairs yield and oil content. However, the mechanisms underlying heat-stress effects on B. napus seed photosynthesis and oil accumulation remain elusive. In this study, we showed that heat stress resulted in reduction of seed oil accumulation, whereas the seed sugar content was enhanced, which indicated that incorporation of carbohydrates into triacylglycerols was impaired. Photosynthesis and respiration rates, and the maximum quantum yield of photosystem II in developing seeds were inhibited by heat stress. Transcriptome analysis revealed that heat stress led to up-regulation of genes associated with high light response, providing evidence that photoinhibition was induced by heat stress. BnWRI1 and its downstream genes, including genes involved in de novo fatty acid biosynthesis pathway, were down-regulated by heat stress. Overexpression of BnWRI1 with a seed-specific promoter stabilized both oil accumulation and photosynthesis under the heat-stress condition, which suggested BnWRI1 plays an important role in mediating the effect of heat stress on fatty acid biosynthesis. A number of sugar transporter genes were inhibited by heat stress, resulting in defective integration of carbohydrates into triacylglycerols units. The results collectively demonstrated that disturbances of the seed photosynthesis machinery, impairment of carbohydrates incorporation into triacylglycerols and transcriptional deregulation of the BnWRI1 pathway by heat stress might be the major cause of decreased oil accumulation in the seed.

Indoleamine 2,3-dioxygenase (IDO), an immune checkpoint, is a promising target for cancer immunotherapy. However, current IDO inhibitors are not approved for clinical use yet; therefore, new IDO inhibitors are still demanded. To identify new IDO inhibitors, we have built naive Bayesian (NB) and recursive partitioning (RP) models from a library of known IDO inhibitors derived from recent publications. Thirteen molecular fingerprints were used as descriptors for the models to predict IDO inhibitors. An in-house compound library was virtually screened using the best machine learning model, which resulted in 50 hits for further enzyme-based IDO inhibitory assays. Consequently, we identified three new IDO inhibitors with IC(50) values of 1.30, 4.10, and 4.68 μM. These active compounds also showed IDO inhibitory activities in cell-based assays. The compounds belong to the tanshinone family, a typical scaffold family derived from Danshen (a Chinese herb), the dried root of Salvia miltiorrhiza, which has been widely used in China, Japan, the United States, and other European countries for the treatment of cardiovascular and cerebrovascular diseases. Thus, we discovered a new use for Danshen using machine learning methods. Surface plasmon resonance (SPR) experiments proved that the inhibitors interacted with the IDO target. Molecular dynamic simulations demonstrated the binding modes of the IDO inhibitors.

Water sample pretreatment system and titration detection system were intensely studied based on National environmental protection standards HJ 537-2009 ‘Water quality-Determination of ammonia nitrogen-Distillation-neutralization titration’. These studies pointed out several problems and difficulties, such as an accurate sampling of water, automatically regulate pH, the low efficiency of distillation, short stabilization time of mixing indicator, and the challenge in determining titration endpoints. Some technical solutions exist, and a new on-line monitor of ammonia nitrogen base on distillation-potentiometric titration was designed to measure metering performance indexes, method detection limit (MDL), and limit of quantitation (LOQ). The results showed a maximum absolute error of 0.0398 mg/L on low concentration sample analysis (≤2 mg/L), the relative error reached 1.4% on high concentration sample analysis (>2 mg/L). The method detection limit and limit of quantitation were 0.025 mg/L and 0.17 mg/L, respectively, which could satisfy both A class and B class instruments of metering performance requirements in verification regulation of ammonia nitrogen automatic monitor.

Four kinds of strontium borates were prepared and characterized by XRD, SEM, EDS, TG-DTA and Hammett titration method, and their catalytic activities were examined in the transesterification of glyceryl tributyrate with methanol for the first time. The separate effects of the molar ratio of methanol to oil, the reaction time, and reusability were investigated. In addition, the catalytic activities of Sr(OH)2 and SrCO3 were also examined for the comparison. The results showed that the basicity and catalytic activity of these catalysts were decreased as the following order: Sr(OH)2 > SrB2O4·4H2O > SrB6O10·5H2O > SrB2O4 > SrB6O10 > SrCO3, and the reusability decreases as the following order: anhydrous strontium borates (SrB2O4, SrB6O10) > hydrated strontium borates (SrB2O4·4H2O, SrB6O10·5H2O) > Sr(OH)2. The results indicate that the SrB2O4·4H2O with regular morphology, which was obtained at low temperature by a simple preparation method, might be as one kind of good potential alkaline earth salts catalyst for transesterification. Moreover, the possible reaction mechanism is proposed and analyzed.

This article describes a novel hydrothermal deposition method for preparing highly dispersed NiW/γ-Al2O3 catalysts and demonstrates its advantages over the conventional impregnation method. Via the hydrothermal precipitation reactions between sodium tungstate and hydrochloric acid and between nickel nitrate and urea, respectively, the active species W and Ni were deposited on γ-Al2O3. In the hydrothermal deposition of WO3, a surfactant hexadecyltrimethyl ammonium bromide (CTAB) was used to prevent the aggregation of WO3. The characterization results obtained by means of X-ray photoelectron spectroscopy (XPS), N2 adsorption and high-resolution transmission electron microscopy (HRTEM) measurements showed that compared with the catalyst prepared by the conventional impregnation method, the catalyst with the same metal contents prepared by the hydrothermal deposition had much higher W and Ni dispersion, higher specific surface area, larger pore volume, the significantly decreased slab length and slightly increased stacking degree of sulfided W species, leading to the significantly enhanced dibenzothiophene (DBT) hydrodesulfurization (HDS) activity. The DBT HDS assessment results also revealed that the catalyst containing 17.7 wt% WO3 and 2.4 wt% NiO prepared by the hydrothermal deposition method had the similar DBT HDS activity as a commercial NiW/γ-Al2O3 catalyst containing 23 wt% WO3 and 2.6 wt% NiO, resulting in the greatly decreased amount of active metals for achieving the same HDS activity.

This article describes a novel modification method consisting of steaming and subsequent citric acid leaching to finely tune acidity and pore structure of HZSM-5 zeolite and thereby to enhance the on-stream stability of the zeolite derived fluid catalytic cracking (FCC) gasoline hydro-upgrading catalyst. A series of dealuminated HZSM-5 zeolites and their derived catalysts were prepared and characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), 27Al MAS NMR, nitrogen adsorption, temperature programmed desorption of ammonium (NH3-TPD) and infrared (IR) spectroscopy of chemisorbed pyridine. The results showed that the citric acid leaching could preferentially remove the extra-framework Al (EFAl) species formed by steaming treatment and thus reopen the EFAl-blocked pore channels of the steamed zeolite. The steaming treatment at a suitable temperature and subsequent citric acid leaching not only decreased the strength of acid sites to a desirable degree but also increased the ratio of medium and strong Lewis acidity to medium and strong Bronsted acidity, both of which conferred the resulting catalyst with superior selectivity to aromatics, good hydroisomerization activity and gasoline research octane number (RON) preservability, as well as enhanced on-stream stability. The results fully demonstrated that the treatments by steaming and followed citric acid leaching can serve as an important method for adjusting the physicochemical properties of HZSM-5 zeolite.

The present study aimed to confirm whether the ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH) is a sensitive indicator, and whether it can be used as a biomarker for the clinical diagnosis of atherosclerosis. Apolipoprotein E (ApoE)-/- mice were randomly divided into four groups and fed with a high methionine diet for 15 weeks. Serum levels of homocysteine (Hcy) were measured using an automatic biochemistry analyzer. The concentrations of SAM and SAH were determined using high‑performance liquid chromatography. The methylation levels of B1 repetitive elements, adipocyte fatty acid binding protein (FABP4), monocyte chemoattractant protein-1 (MCP-1) and extracellular superoxide dismutase (EC‑SOD) were analyzed using nested touchdown-methylation-specific-polymerase chain reaction analysis. After 15 weeks, compared with the normal control group, serum concentrations of Hcy were significantly increased by 1.15‑, 2.54‑ and 1.17‑fold (P

The characteristic of Myoglobin as mimetic enzyme was studied and applied in the determination of H2O2 witho-phenylenediamine as substrate. The absorbance obtained at 40°C was found to be proportional to the concentration of H2O2 in the range of 2.0×10−5–2.0×10−7 mol/L, with a correlation coefficient of 0.999 1. The proposed method is simple and highly sensitive to a detection limit of 2.7×10−8 mol/L. The relative standard deviations were within 5% for the determination of different concentrations of H2O2. Satisfied results were obtained in the determination of H2O2 in rainwater by this method, and the recoveries were at the range of 97.2%–105.4%.

A pure calcium borate Ca2[B2O4(OH)2]·0.5H2O has been synthesized under hydrothermal condition and characterized by XRD, FT-IR and TG as well as by chemical analysis. The molar enthalpy of solution of Ca2[B2O4(OH)2]·0.5H2O in HC1·54.582H2O was determined. From a combination of this result with measured enthalpies of solution of H3BO3 in HC1·54.561H2O and of CaO in (HCl + H3BO3) solution, together with the standard molar enthalpies of formation of CaO(s), H3BO3(s) and H2O(l), the standard molar enthalpy of formation of −(3172.5 ± 2.5) kJ mol−1 of Ca2[B2O4(OH)2]·0.5H2O was obtained.

Kinetics of dissolution and transformation of chloropinnoite (2MgO·2B2O3· MgCl2·14H2O) in 4.5% (wt%) boric acid aqueous solution at 303 K had been studied, and the kinetic process and mechanism were investigated by the Raman spectroscopy. According to the kinetic curve, the process of dissolution and phase transformation can be divided into three stages: dissolution stage, phase transformation induction period, and crystallization stage. The experimental results showed that when chloropinnoite dissolved in boric acid aqueous solution, MgCl2 was removed and midproduct (MgB2O(OH)6·H2O) dissolved at the same time, which was different from that of in water. Kurnakovite was a final product. The experimental data of the crystallization process have been fitted with the following mathematical modification with the aid of simplex optimum method and Runge–Kutta digital solution of differential equation system: −dc/dt = 6.31(c−0.3906)2 + 0.975(c−0.3906). Based on our experimental results and the Raman spectroscopy, kinetics and mechanism of dissolution, phase transformation, and crystallization of borate in chloropinnoite–boric acid water system are discussed. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 38: 136–143, 2006

A new magnesium borate, β-2MgO·3B2O3·17H2O, has been synthesized by the method of phase transformation of double salt and characterized by XRD, IR, and Raman spectroscopy as well as by TG. The structural formula of this compound was Mg[B3O3(OH)5]·6H2O. The enthalpy of solution of β-2MgO·3B2O3·17H2O in approximately 1 mol dm−3 HCl was determined. With the incorporation of the standard molar enthalpies of formation of MgO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(10256.39±4.93) kJ mol−1 of β-2MgO·3B2O3·17H2O was obtained. Thermodynamic properties of this compound was also calculated by group contribution method.

A new magnesium borate Mg2[B2O4(OH)2]·H2O has been synthesized by the method of phase transformation of double salt at hydrothermal condition and characterized by XRD, IR, TG and DSC. The enthalpy of solution of Mg2[B2O4(OH)2]·H2O in 0.9764 mol L−1 HCl was determined. With the incorporation of the enthalpies of solution of H3BO3 in HCl (aq), of MgO in (HCl+H3BO3) (aq), and the standard molar enthalpies of formation of MgO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(3185.78±1.91) kJ mol−1 of Mg2[B2O4(OH)2]·H2O was obtained.

The molar enthalpies of solution of 2MgO · 2B 2 O 3 · MgCl 2 · 14H 2 O in approximately 1 mol · dm −3 aqueous hydrochloric acid (HCl) and of MgCl 2 · 6H 2 O(s) in aqueous (approximately 1 mol · dm −3 HCl + MgCl 2 + H 3 BO 3 ) at T =298.15 K were determined. From a combination of these results with measured enthalpies of solution of boric acid (H 3 BO 3 ) in HCl(aq) and of magnesium oxide (MgO) in aqueous (HCl + H 3 BO 3 ) solution, together with the standard molar enthalpies of formation of MgO(s), H 3 BO 3 (s), MgCl 2 · 6H 2 O(s) and H 2 O(l), the standard molar enthalpy of formation of −(8812 ± 3) kJ · mol −1 of 2MgO · 2B 2 O 3 · MgCl 2 · 14H 2 O was obtained. Thermodynamic properties of this compound were also calculated by group contribution method.

Hydrated cesium borates have been synthesized by the reaction of Cs(2)CO(3) with H(3)BO(3) aqueous solution. After reaction equilibria were reached, liquid and solid phases were separated and the FT-IR difference and Raman spectra of each phase were recorded, respectively. The assignments of the recorded FT-IR absorption frequencies and Raman shift are given. The main polyborate anions and their interaction in borate aqueous solution have been proposed. The relations between the existing forms of polyborate anions and the crystallizing solid phases, Cs(2)B(4)O(7).5H(2)O and CsB(5)O(8).4H(2)O, have been gained.

A new magnesium borate MgO·3B 2 O 3 ·3.5H 2 O has been synthesized by the method of phase transformation of double salt and characterized by XRD, IR and Raman spectroscopy as well as by TG. The structural formula of this compound was Mg[B 6 O 9 (OH) 2 ]·2.5H 2 O. The enthalpy of solution of MgO·3B 2 O 3 ·3.5H 2 O in approximately 1 mol dm −3 HCl was determined. With the incorporation of the standard molar enthalpies of formation of MgO(s), H 3 BO 3 (s), and H 2 O(l), the standard molar enthalpy of formation of −(5595.02±4.85) kJ mol −1 of MgO·3B 2 O 3 3.5H 2 O was obtained. Thermodynamic properties of this compound was also calculated by group contribution method.

The enthalpies of solution of magnesium oxysulfate compounds MgSO 4 ·5MgO·7H 2 O and MgSO 4 ·5MgO·8H 2 O in approximately 1 mol dm −3 aqueous hydrochloric acid were determined. From these results and the enthalpies of solution of MgSO 4 ·7H 2 O and MgO in HCl(aq) respectively, the standard molar enthalpies of formation of −(6496.00±0.73) kJ mol −1 for MgSO 4 ·5MgO·7H 2 O and −(6800.17±0.55) kJ mol −1 for MgSO 4 ·5MgO·8H 2 O were obtained by using the standard molar enthalpies of formation of MgO(s), MgSO 4 ·7H 2 O(s) and H 2 O(l). The standard molar entropies of formation of MgSO 4 ·5MgO·7H 2 O and MgSO 4 ·5MgO·8H 2 O were calculated from the thermodynamic relation with the standard molar Gibbs free energy of formation of MgSO 4 ·5MgO·7H 2 O and MgSO 4 ·5MgO·8H 2 O computed from a group contribution methods.

The enthalpies of solution of Rb 2 Ca[B 4 O 5 (OH) 4 ] 2 ·8H 2 O in approximately 1 mol dm −3 aqueous hydrochloric acid and of RbCl in aqueous (hydrochloric acid+boric acid +calcium oxide) were determined. From these result and the enthalpies of solution of H 3 BO 3 in approximately 1 mol dm −3 HCl (aq), and of CaO in aqueous (hydrochloric acid+boric acid), the standard molar enthalpy of formation of −10,308.06±6.57 kJ mol −1 for Rb 2 Ca[B 4 O 5 (OH) 4 ] 2 ·8H 2 O was obtained from the standard molar enthalpy of formation of CaO (s), RbCl (s), H 3 BO 3 (s) and H 2 O (l). The standard molar entropy of formation of Rb 2 Ca[B 4 O 5 (OH) 4 ] 2 ·8H 2 O was calculated from the thermodynamic relation with the standard molar Gibbs free energy of formation of Rb 2 Ca[B 4 O 5 (OH) 4 ] 2 ·8H 2 O computed from a group contribution method.

The dissolution and transformation of chloropinnoite in boric acid solution at 303 K has been studied using FT-IR difference spectroscopic technique. After equilibrium was reached, liquid and solid phases were separated and FT-IR spectra of each phase were recorded, FT-IR spectroscopic analysis of solid phases indicated that the transformation products, with the increase of boron-concentration in solution, were 2MgO · 3B 2 O 3 · 15H 2 O (inderite), 2MgO · 3B 2 O 3 · 15H 2 O (kurnakovite), MgO · 3B 2 O 3 · 7.5H 2 O, and MgO · 3B 2 O 3 · 7H 2 O, respectively. The main polyborate anions and their interaction in each borate saturated aqueous solution have been proposed according to the FT-IR difference spectra of borate in liquid phase, and some assignments were tentatively given firstly. The relations between the existing forms of polyborate anions and the crystallizing solid phases have been gained.

A spectrofluorimetric method for the determining riboflavin (VB2) based on its enhancement on the fluorescence of hemoglobin-catalyzed enzymatic reaction was proposed. The proposed method consisted of two reactions. One was the photochemical reaction of VB2, the other was a hemoglobin-catalyzed enzymatic reaction. The optimal experimental conditions for the determinations were established. The linear range of the method was 5.0×10−9−1.0×10−7 mol/L of VB2. The detection limit was calculated to be 3.65×10−9 mol/L. The relative standard deviation of this method was 2.3% at 7.0×10−2 mol/L for 11 determinations.

The title compound was prepared by using α-SiW 9 as precursor and was characterized by IR, UV–Vis–NIR spectroscopy. Its crystal structure was determined by X-ray diffraction. The compound crystallized in monoclinic system, space group P 2 1 with a =12.599(3), b =12.649(4), c =17.814(4)A, γ =90.11(3)°, V =2838.9(10)A 3 , Z =2, Mr =2966.24 g mol −1 , D c =3.467 g cm −3 , λ (MoK α )=0.71073 A, μ =19.279 mm −1 , F (000)=2634. The final R =0.0666, Rw =0.0865. The title compound consists of heteropoly anions, potassium ions and water molecules. The anion has the well-known Keggin structure and the 12 metal atoms in the anion were in a random distribution.

A systematic investigation of recess-ohmic contact by inductively coupled plasma etching using four layers Ti/Al/Ni/Au metal on un-doped AlGaN/GaN HEMT structure with a thin AlN spacer layer grown on silicon substrate were performed. Although the insertion of the thin AlN spacer layer effectively increases the two-dimensional electron gas concentration and electron mobility due to the enhanced 2DEG confinement, it causes much difficulty in forming ohmic contacts. This problem has been resolved by recess-ohmic approach prior to ohmic metalization. Improved HEMT characteristics were demonstrated by this technique. About 17.5% of increase in IDmax and 12.5% of increase in gmmax were observed by recess ohmics. This improved device performance is due to the reduction of Rc, Rd and Rs values by recess-ohmics. From this investigation, we found that recess-ohmics are essential to achieve high performance device characteristics in un-doped AlGaN/GaN HEMTs with AlN spacer layer grown on Si substrate (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A new synthetic method of szaibelyite (2MgO·B2O3·H2O) has been reported. The enthalpy of solution of 2MgO·B2O3·H2O in 2.9842 mol dm−3 HCl (aq) was determined. From a combination of this result with measured enthalpies of solution of H3BO3 in 2.9842 mol dm−3 HCl (aq) and of MgO in (HCl+H3BO3) solution, together with the standard molar enthalpies of formation of MgO (s), H3BO3 (s), and H2O (l), the standard molar enthalpy of formation of −(2884.36±1.82) kJ mol−1 of 2MgO·B2O3·H2O was obtained.

Perylene dyes have been widely used as photoreceptors in organic photovoltaics because of their outstanding photo-, thermal and chemical stability as well as their excellent photophysical properties. Herein we describe a novel generation of perylene dyes based on N-(2.6-diisopropylphenyl)-perylene-3,4-dicarboximide. The optical properties of these novel perylenes can be finely tuned via the substituents in the 1-, 6- and 9-positions of the perylene core. The facile synthesis, tunable orbital and absorption properties, and electrochemical potentials help us to design efficient perylene sensitizers for solar-cell applications.

In order to meet the requirements of real-time measurement and regulation, a capacitance concentration measurement system for pulverized coal is developed in this paper, which is designed based on differential-capacitive, relaxation oscillator and wireless sensor networks. The experimental results indicate that the linearity and the resolution of the measurement system can respectively reach 7.5% and 0.005% under laboratory conditions. (4 pages)

Homocysteine (Hcy) is an independent risk factor for cardiovascular disease, but the molecular mechanisms causing atherosclerosis in monocytes remain poorly characterized. The objective of the present study was to investigate the effects of Hcy on DNA methylation of PPARalpha,gamma and the underlying mechanism of PPARalpha,gamma expression that was induced by Hcy in monocytes. About 50, 100, 200, and 500 microM Hcy were added to the monocytes cultured for 48 h. PPARalpha,gamma that acted as lipid sensors and bind with mM affinities to ligands of antiatherosclerosis were determined by real-time reverse transcription-polymerase chain reaction and Western blotting in monocytes. Here, we used a high-throughput quantitative methylation assay that utilizes fluorescence-based real-time polymerase chain reaction to determine the levels of the PPARalpha,gamma DNA methylation. S-adenosylmethionine (SAM) level and S-adenosylhomocysteine (SAH) level were detected by high performance liquid chromatography. Results indicated that the levels of PPARalpha,gamma promoter methylation in monocytes cultured with Hcy were increased in comparison with the control group, and the peak was in the 100 muM Hcy group, however, a dose-dependent increase with increasing Hcy was not seen. Hcy also decreased mRNA and protein levels of PPARalpha,gamma in monocytes. Further, with the addition of Hcy, the levels of SAH were elevated, the levels of SAM and the ratio of SAM/SAH were lower, and the activity of C-5MT-ase was increased. In conclusion, these results suggest that PPARalpha,gamma DNA methylation induced by Hcy may represent an important mechanism to explain atherosclerosis, which may become a therapeutic target for preventing atherosclerosis induced by Hcy.

A novel fluorimetric method for determination of laccase activity in organic solvents is proposed, based on the oxidation ofo-phenylenediamine (1,2-diaminobenzene, OPDA) catalyzed by laccase yielding 2,3-diaminophenazine. The optimal conditions for laccase in organic media areT=55°C, pH=6.5, 1.0×10−2mol/L OPDA, 1.25 mL ethanol, 1.25 mL 1,4-dioxane and 1.25 mL acetone. The linear range of the method proposed in ethanol, 1,4-dioxane and acetone media were 0.44–19.33, 0.11–20.85, 0.38–21.05 U with the detection limit of 0.088, 0.022, 0.076 U, respectively. The proposed method has been applied to the analysis of laccase activity of real samples with more accurate and sensitive than that of the previous method reported.

Raman spectra of supersaturated aqueous solution of MgO·B2O3–32%MgCl2–H2O during acidification/alkalization and dilution have been studied. The assignments of the recorded Raman shift are given. The main existing forms of polyborate anions and their interaction in borate aqueous solution have been proposed through spectroscopic analysis. The experimental results indicate that the higher concentration of cation are beneficial not only to the dissolution of boric acid but also to the polymerization of polyborate anions. The existing forms and interaction among them also depend on the concentration of boron and the pH value in solution.

A study on the single event transient (SET) induced by a pulsed laser in a silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) is presented in this work. The impacts of laser energy and collector load resistance on the SET are investigated in detail. The waveform, amplitude, and width of the SET pulse as well as collected charge are used to characterize the SET response. The experimental results are discussed in detail and it is demonstrated that the laser energy and load resistance significantly affect the SET in the SiGe HBT. Furthermore, the underlying physical mechanisms are analyzed and investigated, and a near-ideal exponential model is proposed for the first time to describe the discharge of laser-induced electrons via collector resistance to collector supply when both base-collector and collector-substrate junctions are reverse biased or weakly forward biased. Besides, it is found that an additional multi-path discharge would play an important role in the SET once the base-collector and collector-substrate junctions get strongly forward biased due to a strong transient step charge by the laser pulse.