Thermally Induced Chemiluminescence of Barley Leaves

Abstract— An unconventional band in the thermoluminescence glow curve of barley leaves at about +50°C was examined. In contrast to bands usually observed around +50°C, this band (designated as CL) is not related to photosynthetic electron transport in photosystem II. The appearance of the CL band (1) requires previous freezing of the sample, (2) is not influenced by light excitation and (3) depends on the presence of oxygen. In pure oxygen the glow curves for both leaves and chloroplast suspension exhibit three maxima at about +40°C, +65°C and +90°C. Based on the emission spectra of the CL band and measurements with etiolated leaves, we suppose that the majority of emission corresponding to the CL band originates from chlorophyll. A lipoxygenase inhibitor, butylated hydroxytoluene, and sodium azide decrease the intensity of the CL band. We propose that the mechanism leading to emission of the CL band involves thermally stimulated production of an active oxygen species that results in lipid peroxidation.     

高温水热合成具有高稳定性的有序介孔材料

高温水热合成路线作为合成具有超高稳定性的介孔材料越来越受到人们的重视.本文对高温水热合成有序介孔材料的发展过程作一个简单的综述,合成路线包括使用碳氟表面活性剂和碳氢表面活性剂作为复合模板,有机季铵盐与碳氢表面活性剂作为复合模板以及最近报道的采用碳氢表面活性剂作为单一模板来合成系列的有序介孔材料,其组成为二氧化硅、氧化钛硅以及聚合物等.     

Photoacoustic Imaging of Nanoparticle Transport in the Kidneys at High Temporal Resolution

Noninvasive monitoring of kidney elimination of engineered nanoparticles at high temporal and spatial resolution will not only significantly advance our fundamental understandings of nephrology on the nanoscale, but also aid in the early detection of kidney disease, which affects more than 10 % of the worldwide population. Taking advantage of strong NIR absorption of the well‐defined Au₂₅(SG)₁₈ nanocluster, photoacoustic (PA) imaging was used to visualize its transport in situ through the aorta to the renal parenchyma and its subsequent filtration into the renal pelvis at a temporal resolution down to 1 s. High temporal and spatial resolution imaging of Au₂₅(SG)₁₈ kidney elimination allowed the accurate quantification of the glomerular filtration rate (GFR) of individual kidneys in normal and pathological conditions, broadening the biomedical applications of engineered nanoparticles in preclinical kidney research.     

Synthesis and Functional Properties of Symmetrically Naphthyl-Based Oligoarylenes with High Glass-Transition Temperatures

Symmetrically naphthyl‐based π‐conjugated oligoarylenes, OPP(4)Ph‐TNp, OPP(4)An‐TNp and OPP(4)OX‐TNp have successfully been synthesized by a divergent approach using Pd‐catalyzed Suzuki cross‐coupling reaction of diiodo‐ or dibromo‐oligoarylene and arylboronic acid as a key step. Their optical, electrochemical and thermal properties have also been characterized. These newly synthesized naphthyl‐based oligoarylenes show highly morphological (T_g 149–187°C) and thermal (T_dec 509–597°C) stabilities as well as exhibit potential applications in optoelectronic fields.     

Determination of Zinc Sulfide Solubility to High Temperatures

A new experimental set-up and methodology for the measurement of ZnS solubility in aqueous solutions at 40, 60 and 80 °C (atmospheric pressure) is presented. The methodology implemented includes the preparation of the samples in a reduced oxygen atmosphere, particle size analysis of ZnS, quality control of the analytical technique and evaluation of equilibration time. ZnS solubility analyses were run for prolonged times (up to 11 days) to ensure that equilibrium conditions were met. The equilibration time was explored at three temperatures (40, 60 and 80 °C) observing small variations in the time required to reach the solid–liquid equilibrium at each temperature. Equilibrium was reached within 72 h. The concentration of zinc and of total sulfur were determined using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The experimental solubility data show an exponential dependency of the solubility with respect to temperature. An increase of 40 °C results in an increase of roughly 12 times for the solubility of ZnS.     

Sensitive Detection of Aromatic Molecules by Laser Photoacoustic Spectrometry: Signal Enhancement by Fluorescence Quencher

Highly sensitive detection of aromatic molecules has been investigated by pulsed laser excitation. A cylindrical cell surrounded by a piezoelectric transducer has improved the detection limit. Fluorescence quencher, CH₃NO, increased the photoacoustic signal of perylene up to three times and the signal-to-noise ratio by about 50%. Typical detection limits of pyrene and perylene were 0.4 ppb in hexane and 6.7 ppb in methanol with nitromethane, respectively.     

Studies on Redispersion and Stability of Platinum in Pt/MgO System during Oxygen Treatment at High Temperatures

Transmission Electron Microscopy and X-ray Diffraction showed that high temperature oxygen treatment results in redispersion of Pt/MgO system. Two catalysts in this study were prepared by impregnation using H₂PtCl₆ or Pt(C₅H₇O₂)₂ as the precursors and two MgO supports of different purity. Pt/MgO system indicated a high stability in oxygen at temperature ranging from 550 to 700°C.     

Solid-Oxide Electrochemical Cell for Determining the Diffusion of Hydrogen in Nitrogen at High Temperatures

Procedure was developed for measuring the diffusion coefficient of hydrogen in its mixture with nitrogen in the temperature range 450–600°C under atmospheric pressure. This is done in an electrochemical cell based on a solid-oxide electrolyte with proton conductivity of composition BaCe_0.7Zr_0.1Y_0.2O_3–δ. The procedure makes it possible to trace how the hydrogen diffusion coefficient varies with temperature and hydrogen concentration in nitrogen. It is shown that the hydrogen diffusion coefficient grows with increasing hydrogen concentration, its temperature dependence is of power-law type with n = 1.5, and it is in satisfactory agreement with the theoretical temperature dependence     

Biological Characterization of a Pituitary Monkey Lutropin Preparation after Chromatofocusing or after High Performance Anion Exchange Chromatography

Abstract

The Pharmacia Fast Protein Liquid Chromatography System equiped with a Mono P HR 5/10 chromatofocusing column was used to characterize the distribution of different bioactive forms of a cynomolgus (Macaca bascicularis) pituitary lutropin preparation. The results were compared with the profiles obtained after running the preparation on a Waters DEAE anion exchange column using eluants in the pH range from 6.0 to 8.0. The distribution of preserved biological activity were studied in respective eluted fractions from the different experiments of the applied preparation. Seventy-six percent of the bioactivity was recovered after chromatofocusing whereas preserved bioactivity after ion exchange chromatography ranged between 61–78% at pH 6.5 to 7.5. No bioactivity was restored after elution at pH 6.0 or 8.0.     

Phase Transformation During the Heat Treatment of Sol-Gel Mullite

The mechanism of mullite formation depends upon the method of combining the silica and alumina-containing reactants. In this work, the effects of the processing variables (dilution, pH, gelling temperature and water content) on mullite formation were investigated. Monophasic gel was synthesized from aluminium nitrate nanohydrate dissolved in an absolute ethyl alcohol and silica sol mixture. The gelling was performed at room temperature and at 60°C. It was found experimentally that the temperature of mullite formation depends on the microstructure of the gel. The lowest temperature of mullite formation (970°C) was observed when the mullite gel was prepared at low pH (pH=1), low water content and high gelling temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

反相高效液相色谱法制备银杏叶中聚戊烯醇同系物单体

利用制备高效液相色谱法从银杏叶中分离制备了聚戊烯醇同系物单体。在HiQ sil C18柱上,以异丙醇-甲醇-正己烷-水(体积比为50∶25∶15∶4)为流动相,流速10 mL/min,采用等度洗脱方式,制备了8种化合物,经紫外光谱、红外光谱及质谱分析,确认它们分别为C70,C75,C80,C85,C90,C95,C100和C105聚戊烯醇,其中主要成分为C85及C90聚戊烯醇。高效液相色谱分析表明,制备的C75C105聚戊烯醇化合物的纯度均在96%(质量分数)以上。在该色谱条件下,各色谱峰达到了基线分离,     

Production of High Temperatures in the Chemical Laboratory: Examples of Application in Lanthanoid Oxo-Chemistry

High-temperature reactions have always been a fascinating although difficult field of experimentation for the chemist. In the case of solid-state reactions the problems with apparatus increase exponentially with rising temperature, so that especially in this area of inorganic chemistry the modern techniques of producing high temperatures—from the solar furnace to the high-power CO₂ laser—have yielded new and interesting possibilities, particularly in the field of metastable high-temperature compounds.     

高温非平衡条件下氟原子亲电动力学的激波管研究

To study electron affinity kinetics, a shock tube method was applied, in which the test gas was ionized by a reflected shock wave and subsequently quenched by a strong rarefaction wave. As the quenching speed of 106 K/s was reached, a nonequilibrium ionization recombination process occurred, which was dominated by ion recombination with electrons. A Langmuir electrostatic probe was used to monitor variation in the ion number density at the reflection shock region. The working state of the probe was analyzed, and a correction was introduced for reduction of the probe current due to elastic scattering in the probe sheath. The three body electron affinity rate coefficient of the fluorine atom over the temperature range 1200 to 2200 K in an ambiance of argon gas was directly determined. The temperature dependence of electron affinity rate coefficient was discussed.     

Characterization of Thermally Stable Brønsted Acid Sites on Alumina‐Supported Niobium Oxide after Calcination at High Temperatures

Thermally stable Brønsted acid sites were generated on alumina‐supported niobium oxide (Nb₂O₅/Al₂O₃) by calcination at high temperatures, such as 1123 K. The results of structural characterization by using Fourier‐transform infrared (FTIR) spectroscopy, TEM, scanning transmission electron microscopy (STEM), and energy‐dispersive X‐ray (EDX) analysis indicated that the Nb₂O₅ monolayer domains were highly dispersed over alumina at low Nb₂O₅ loadings, such as 5 wt %, and no Brønsted acid sites were presents. The coverage of Nb₂O₅ monolayer domains over Al₂O₃ increased with increasing Nb₂O₅ loading and almost‐full coverage was obtained at a loading of 16 wt %. A sharp increase in the number of hydroxy groups, which acted as Brønsted acid sites, was observed at this loading level. The relationship between the acidic properties and the structure of the material suggested that the bridging hydroxy groups (Nb? O(H)? Nb), which were formed at the boundaries between the domains of the Nb₂O₅ monolayer, acted as thermally stable Brønsted acid sites.     

Performance of a New Thermostable Mannanase in Breaking Guar-Based Fracturing Fluids at High Temperatures with Little Premature Degradation

A new thermostable β-1,4-mannanase (DtManB) cloned from Dictyoglomus thermophilum CGMCC 7283 showed the maximum activity towards hydroxypropyl guar gum at 80 °C, with a half-life of 46 h. DtManB exhibited good compatibility with various additives of fracturing fluid, retaining more than 50 % activity in all the cases tested. More importantly, premature degradation could be alleviated significantly when using DtManB as breaker, because at 27 and 50 °C it displayed merely 3.7 and 18.5 % activities compared to those at 80 °C. In a static test, 0.48 mg DtManB could break 200 mL borax cross-linked fracturing fluid dramatically at 80 °C, and merely 18 mPa s of the viscosity was detected even after the broken fluid was cooled down and only 161.4 mg L^?1 of the residue was left after the enzymatic reaction. All these positive features demonstrate the great potential of this mannanase as a new enzyme breaker for application in enhanced recovery of petroleum oil.     

高效液相色谱法测定烟叶提取物中茄尼醇的含量

 采用硅胶色谱柱 ,以正己烷 异丙醇 (体积比为 98∶2 )混合液为流动相 ,在紫外检测波长设定为 2 15nm的高效液相色谱仪上测定了烟叶提取物中茄尼醇的含量。实验结果表明 :方法在茄尼醇进样量为 1μg～ 10 μg时有良好线性关系 (Y =16 6 2 0 4X - 32 5 3,r=0 9997) ;加标回收实验 (n =6 )的平均回收率为 98 1% ,RSD为 1 9% ;方法简便 ,有良好的精密度和准确性。     

磁疗手术胆结石的红外光谱观测

本文报道用Nicolet 170 SXFT-IR红外光谱仪观测磁疗手术胆结石、磁疗破碎排出胆结石及服中草药破碎胆结石的红外光谱,分析并比较了它们的光谱特征。     

Proteomics Profiling of the Urine of Patients with Hyperthyroidism after Anti-Thyroid Treatment

Hyperthyroidism, which is characterized by increased circulating thyroid hormone levels, alters the body’s metabolic and systemic hemodynamic balance and directly influences renal function. In this study, the urinary proteome of patients with hyperthyroidism was characterized using an untargeted proteomic approach with network analysis. Urine samples were collected from nine age-matched patients before and after carbimazole treatment. Differences in the abundance of urinary proteins between hyperthyroid and euthyroid states were determined using a 2D-DIGE coupled to MALDI-TOF mass spectrometry. Alterations in the abundance of urinary proteins, analyzed via Progenesis software, revealed a statistically significant difference in abundance in a total of 40 spots corresponding to 32 proteins, 25 up and 7 down (≥1.5-fold change, ANOVA, p ≤ 0.05). The proteins identified in the study are known to regulate processes associated with cellular metabolism, transport, and acute phase response. The notable upregulated urinary proteins were serotransferrin, transthyretin, serum albumin, ceruloplasmin, alpha-1B-glycoprotein, syntenin-1, and glutaminyl peptide cyclotransferase, whereas the three notable downregulated proteins were plasma kallikrein, protein glutamine gamma-glutamyl transferase, and serpin B3 (SERPINB3). Bioinformatic analysis using ingenuity pathway analysis (IPA) identified the dysregulation of pathways associated with cellular compromise, inflammatory response, cellular assembly, and organization and identified the involvement of the APP and AKT signaling pathways via their interactions with interleukins as the central nodes.