Spectral Properties of Single BODIPY Dyes in Polystyrene Microspheres and in Solutions

The absorption, fluorescence, fluorescence quantum yield, and photostability of five BODIPY dyes are characterized and compared as single dyes in two environments, in 40-nm polystyrene spheres and in solution. The absorption and fluorescence spectra of the dyes in spheres are similar in profile but shifted to lower energies compared to those in solution. All the dyes are highly fluorescent, with three having fluorescence quantum yields of 1.0. For three of the five dyes, the yields were the same in spheres as in solution (1.00, 1.00, and 0.73). The high concentration of these dyes in spheres does not quench their fluorescence. For two other dyes the yields dropped, from 1.00 to 0.55 in one case and 0.83 to 0.50 in another, comparing the dyes in solution versus in spheres. The photodegradation of the dyes decreases in spheres compared to in solution in all but one case. For one dye, it decreases as much as 800-fold. Dyes overlooked because of low fluorescence or stability in solution could become useful fluorescent materials in the microsphere environment.     

ICP-AES测定云南楚雄糖尿病患者发样微量元素的研究

探讨微量元素与糖尿病间的关联性及临床意义。采用ICP-AES等离子体发射光谱仪测定了楚雄地区糖尿病患者人发中11种元素,采用2,3-二氨基萘荧光法测定发样中的硒元素。选取糖尿病患者120例,对照组35例。糖尿病组发样中常量元素Ca、Mg低于对照组,P高于对照组;除Cd、Cr、Fe外,微量元素Zn、Se、Ni、Mn、Cu等5种元素低于对照组,并有显著差异(P0.01)。糖尿病组间性别比较数据显示男性除发Ni、Mn、P外,其余元素含量均低于女性,其中发锌远低于女性。3个不同年龄段糖尿病人群的微量元素含量变化显示Fe、P2种元素随年龄增加含量增高;Mg、Cd2种元素随年龄增加含量减少;其余各元素变化情况为Fe、P元素在老年组中较高,Cu、Cd、Mg较低;Mn、Cr、Cu元素含量在中年组中较高,而Zn、Se略低;Zn、Se在青年组较高,而Mn、Cr低。城市人群发中Zn、Cd、Cu、Mg、Ca含量比农村人群高;Se元素含量二者间差别也不大,其余元素含量均低于农村人群。楚雄地区糖尿病患者发中Zn、Se、Mg、Mn4种元素水平低,楚雄地区糖尿病患者致病原因可能与地区属低Se水平和患者体内硒水平低有关。     

北京气候中心气候系统模式对中国四季日平均气温的模拟性能评估

利用去趋势波动分析方法对中国四季日平均气温观测资料进行了研究, 发现四季日平均气温均具有很好的长程相关性特征, 中国西部地区尤其是新疆和西藏的长程相关性较强. 基于观测资料中的这种长程相关性特征, 评估了北京气候中心气候系统模式对中国四季日平均气温的模拟性能, 发现该模式能够较好地反映中国四季日平均气温的长程相关性特征. 总体而言, 模式对春季的日平均气温的长程相关性模拟效果最好, 仅对江南地区的长程相关性的模拟较差; 夏季, 模式模拟误差较大的地区包括中国中东部地区及西藏大部, 其中华北南部、黄淮西部、江南大部、华南等地模拟效果最差; 秋季, 模式对东部沿海及东北大部、华北西南部等地模拟的长程相关性偏强, 而在西北大部模拟的长程相关性明显偏弱; 冬季, 除东部沿海地区模拟的长程相关性偏强外, 全国其余大部分地区接近观测或偏弱, 其中西北、西南、华南北部、江南南部、东北北部偏弱明显, 青藏高原西部偏弱最为显著.     

Ultrastructural study on dynamics of plastids and mitochondria during microgametogenesis in watermelon

Dynamics of plastids and mitochondria during microgametogenesis in watermelon were examined by means of transmission electron microscopy. Plastids are present as proplastids in the microspore and as amyloplasts in the vegetative cell of the bicellular pollen grain, whereas the generative cell is completely devoid of plastids, suggesting that microspore plastids are excluded from the generative cell during the microspore mitotic division. Therefore, watermelon is classified as Lycopersicon type, where plastids exclusion from the generative cell leads to purely maternal plastid inheritance. Mitochondria in the generative cell show noticeable alterations in size and cristae during microgametogenesis. The diameter of mitochondria is about 0.5 μm in the newly born generative cell, while only about 0.16 μm in the spindle-shaped generative cell. Numerous cristae are present in mitochondria in the spherical generative cell, but, in contrast, mere two or three cristae retain in the spindle-shaped generative cell in the mature pollen grain. In conclusion, the size and cristae number of mitochondria in the generative cell are reduced significantly during microgametogenesis in watermelon.     

Isotope variations in white-tailed kites from various habitats in California: possible limitations in assessing prey utilization and population dynamics

White-tailed kite (Elanus leucurus) populations in the 1930s were close to extirpation in the United States. But by the 1940s, an upward trend towards recovery was apparent and continued to their current stable population levels. These dramatic fluctuations in kite numbers may have been related to changes in rodent prey populations due to the conversion of native habitats to agriculture. To address this question, we evaluated the use of stable isotope analysis in determining if a shift in diet could be isotopically differentiated in current and historic kite populations. We first compared delta13C, delta15N, and delta34S values from present-day kite flight feathers and prey fur samples from four locations in California. The total ranges of isotope values for kite and their rodent prey were similar within each site. Carbon isotope values ranged from -27.1 to -22.2 per thousand in Arcata, -26.1 to -16.9 per thousand in Davis, -27.0 to -15.0 per thousand in Cosumnes, and -28.2 to -11.6 per thousand in Santa Barbara. Nitrogen isotope values ranged from 3.2 to 15.7 per thousand in Arcata, 2.8 to 12.7 per thousand in Davis, 4.0 to 15.7 per thousand in Cosumnes, and 1.7 to 20.0 per thousand in Santa Barbara. Sulfur isotope values ranged from -7.8 to 12.4 per thousand in Arcata, -1.1 to 9.2 per thousand in Davis, 0.7 to 10.9 per thousand in Cosumnes, and -8.6 to 15.6 per thousand in Santa Barbara. Carbon, nitrogen, and sulfur isotope values at each site reflect typical trophic enrichments due to physiological processes. At each site, delta13C and delta15N values reflected the influence of a predominantly C3 or a mixed C3/C4 plant community. Sulfur isotope values reflect the influence of predominant marine or terrestrial sulfur sources at each site. However, variability in isotope values may limit the usefulness of such analyses for addressing prey utilization and population dynamics.     

Strain-induced interaction of interstitials in IVA group hcp metals

Strain-induced (elastic) interactions of oxygen, nitrogen and carbon atoms in IVA group metals, α-Ti, Zr, and -Hf, are calculated in the framework of the microscopic Krivoglaz-Kanzaki-Khachaturyan theory. The experimental elastic constants, lattice spacing of the host metal, and concentration expansion coefficients are used as the input numerical parameters. The resulting interactions are stronger in α-Ti than in α-Zr and α-Hf. A comparative analysis of interactions in the hcp IVA group metals with those in bcc and fcc solid solutions reveals the crystal structure effect. In general, the strain-induced interactions of O, N, and C in hcp IVA group metals are weaker than in bcc solid solutions and are stronger than in fcc solid solutions.     

Superconductivity and superfluidity as universal emergent phenomena

Superconductivity (SC) or superfluidity (SF) is observed across a remarkably broad range of fermionic systems: in BCS, cuprate, iron-based, organic, and heavy-fermion superconductors, and in superfluid helium-3 in condensed matter; in a variety of SC/SF phenomena in low-energy nuclear physics; in ultracold, trapped atomic gases; and in various exotic possibilities in neutron stars. The range of physical conditions and differences in microscopic physics defy all attempts to unify this behavior in any conventional picture. Here we propose a unification through the shared symmetry properties of the emergent condensed states, with microscopic differences absorbed into parameters. This, in turn, forces a rethinking of specific occurrences of SC/SF such as high-T_c SC in cuprates, which becomes far less mysterious when seen as part of a continuum of behavior shared by a variety of other systems.     

Summary of FLUCOME 97 Hayama

This article is a summary of the fifth Triennial International Symposium on Fluid Control, Measurement and Visualization, FLUCOME ’97 Hayama, which was held from September 1 to September 4 in 1997 at Hayama, Japan. The FLUCOME symposium was held at first in Tokyo in 1985, the 2nd in 1988 in Sheffield, UK, the 3rd in 1991 in San Fransisco, USA, the 4th in 1994 in Toulouse, France, and came back again to Japan in 1997. FLUCOME ’97 Hayama was sponsored by the Society of Instrument and Control Engineers of Japan and Japan Science Foundation, and co-sponsored by the Japan Society of Mechanical Engineers, the Japan Hydraulics and Pneumatics Society and the Visualization Society of Japan. The participants exchanged new information and deepened their friendship among them. A lot of new ideas and important research results were reported and the new directions in fluid control, measurement and visualization were discussed freely. The sixth symposium chaired by Prof. A. Laneville will be held in Sherbrooke (Québec) Canada in 2000, and the seventh will be held in Italy in 2003.     

ICP-OES法分析桑椹果实成熟过程中14种矿物元素含量的变化

桑椹果实在成熟过程中各种成分不断发生变化,但对期间矿物元素的变化了解甚少。文章以桑椹果实为材料,采用电感耦合等离子体-原子发射光谱(ICP-OES)法对绿色期、粉色期、红色期、黑色期四种不同成熟度桑椹果实的九种必需元素和五种重金属元素含量进行了测定。结果发现,随着果实成熟度的增加,Na,K,Ca,Mg,Fe,Zn,Mn和Cu等元素的含量均出现明显的下降趋势,绿色期桑椹果实中上述各种元素的含量分别为2.99,2 957.49,809.00,559.95,36.30,10.07,2.12和1.32 mg·kg-1,而粉色期上述各种元素的含量下降了62.9%(Zn)至12.3%(Na),红色期上述各种元素的含量分别降至1.63, 2 367.13, 489.30, 221.54, 19.01, 2.64, 0.40和0.59 mg·kg-1,黑色期果实各种元素的含量保持继续下降的趋势,但幅度大大减小。Se元素的含量绿色期最高,为1.24 mg·kg-1,粉色期下降,红色期上升至0.88 mg·kg-1,而黑色期又下降为0.65 mg·kg-1。重金属元素中Pb含量在前三个成熟时期变化不显著,而黑色期大大下降,绿色期最高为0.27 mg·kg-1,未超出国家标准。Cr含量随着果实成熟度的增加而增加,但黑色期又降至粉色期的水平,虽然红色期为54.07 mg·kg-1,但仍未超出国家标准。文章通过测定不同成熟时期桑椹果实的矿物元素含量,为果实采收时期的确定提供理论依据,也为桑椹果实的功能评价和安全评价提供参考数据。     

Electrochemical Behavior of Vanadium Carbide in Neutral Aqueous Electrolytes

The V_2C compound,belonging to the group of two-dimensional transition metal carbonitrides,or MXenes,has demonstrated a promising electrochemical performance in capacitor applications in acidic electrolytes;however,there is evidence to suggest that V_2C is unstable in an acidic environment.On the other hand,the performance of V_2C in neutral aqueous electrolytes is still moderate,and has not yet been systematically studied.The charge storage mechanism in a V_2C electrode,employed in neutral aqueous electrolytes,is investigated via cyclic voltammetry testing and in situ x-ray diffraction(XRD).Good specific capacitances are achieved,specifically208 F/g in 0.5 M Li_2SO_4,225 F/g in 1 M MgSO_4,120 F/g in 1 M Na_2 SO_4,and 104 F/g in 0.5 M K_2SO_4.Using in situ XRD,we observe that,during the charge and discharge process,the c-lattice parameter shrinks or expands by up to 0.25 A in MgSO_4,and 0.29 A in Li_2SO_4 which demonstrates the intercalation/de-intercalation of cations into the d-V_2C layer.     

An investigation of Fe3(PO4)2 — Sarcopside between 1.6K–721 K: Comparision with fayalite

The two octahedral metal positions, M1 and M2, in sarcopside resemble the corresponding sites in fayalite. However, in sarcopside every second M1 site is vacant. The Mössbauer spectra of the two minerals are similar in the paramagnetic region, but different in the magnetic, T_N=66 K in fayalite and 44 K in Fe-sarcopside. Contrary to in fayalite, iron at M1 is non-magnetic, at least down to 2.4 K, in sarcopside but there are indications of a second transition in the interval 1.6 K–2.4 K.     

SRXRF microprobe as a technique for studying elements distribution in Elsholtzia splendens

Elsholtzia splendens is a copper tolerant plant growing in copper mine areas in south of China and accumulates considerable heavy metals in plant tissue. In this study, synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) microprobe was used to study the Cu and other elements distribution in E. splendens. The element (P, S, Cl, K, Ca, Mn, Fe, Cu, Zn) in the leaf epidermis and cross-sections of the stem and leaf could be checked by SRXRF which was considered a sensitive technique for trace element analysis. The highest Cu levels were measured in the vascular tissues of stem and petiole, while Cu levels in mesophyll were higher than in leaf epidermis. The levels of most elements were not higher in trichomes than in other tissues. It seems that the celluar compartmentation of heavy metals in epidermis and epidermal trichomes was not the general feature of all plants. There was a significant correlation between Cu and P, S, Ca in distribution, which suggested P, S, and Ca played an important role in Cu accumulation of E. splendens. Based on the significant correlation between Cu and elements Mn, Fe, and Zn in distribution, it seemed that Cu, Mn, Fe, and Zn could be transported by the same transporters with a broad substrate range.     

An fMRI study of magnitude comparison and exact addition in children

By contrast to the adult literature, in which a consistent parietofrontal network for number processing has been identified, the data from studies of number processing in children have been less consistent, probably due to differences in study design and control conditions. Number processing was examined using functional magnetic resonance imaging in 18 right-handed children (8–12 years) from the Cape Coloured community in Cape Town, South Africa, using Proximity Judgment and Exact Addition (EA) tasks. The findings were consistent with the hypothesis that, as in adults, the anterior horizontal intraparietal sulcus (HIPS) plays a major role in the representation and manipulation of quantity in children. The posterior medial frontal cortex, believed to be involved in performance monitoring in more complex arithmetic manipulations in adults, was extensively activated even for relatively simple symbolic number processing in the children. Other areas activated to a greater degree in the children included the left precentral sulcus, which may mediate number knowledge and, for EA, the head of the caudate nucleus, which is part of a fronto-subcortical circuit involved in the behavioral execution of sequences. Two regions that have been linked to number processing in adults — the angular gyrus and posterior superior parietal lobule — were not activated in the children. The data are consistent with the inference that although the functional specialization of the anterior HIPS may increase as symbolic number processing becomes increasingly automatic, this region and other elements of the parietofrontal network identified in adults are already reliably and robustly activated by middle childhood.     

Efficient Localization Bounds in a Continuous N-Particle Anderson Model with Long-Range Interaction

We establish strong dynamical and exponential spectral localization for a class of multi-particle Anderson models in a Euclidean space with an alloy-type random potential and a sub-exponentially decaying interaction of infinite range. For the first time in the mathematical literature, the uniform decay bounds on the eigenfunction correlators (EFCs) at low energies are proved, in the multi-particle continuous configuration space, in the (symmetrized) norm-distance, which is a natural distance in the multi-particle configuration space, and not in the Hausdorff distance. This results in uniform bounds on the EFCs in arbitrarily large but bounded domains in the physical configuration space, and not only in the actually infinite space, as in prior works on multi-particle localization in Euclidean spaces.     

FAAS测定嫩、老荷叶中7种营养元素含量

采用火焰原子吸收光谱法对嫩、老(成熟)荷叶中K、Ca、Mg、Mn、Fe、Zn、Cu7种营养元素的含量进行测定。结果表明,嫩、老荷叶中7种营养元素含量高低顺序一致,依次为KCaMgMnFeZnCu,但成熟荷叶中钙、锰含量明显高于嫩荷叶,约为嫩荷叶的两倍,铁含量稍高于嫩荷叶,钾、镁、锌、铜含量略低于嫩荷叶。其中成熟荷叶中锰的含量为738.04μg.g-1,比一般中药高出近20倍,荷叶的多种药用价值可能与富含微量元素锰有密切关系。     

Review of in situ X-ray fluorescence analysis technology in China

In the past two decades, the in situ X-ray fluorescence (XRF) technology has been developed rapidly in China, which is mainly due to the rapid development of China's economy and the great demand for rapid qualitative and quantitative analysis of elements in geological exploration, environmental protection, and industrial process analysis. In this article, the development of in situ XRF analysis technology in China is reviewed from three aspects, namely in situ XRF analyzers, in situ XRF analysis technology, and applications of in situ XRF analysis technology. The in situ XRF analyzers are divided into four generations, and the technical characteristics of each generation of analyzers are discussed from the perspectives of X-ray excitation source, detector, electronic circuit unit, and digital signal processing. The progress of X-ray spectrum analysis, matrix effect correction, and correction of uneven effect and humidity effect is reviewed. The representative applications of XRF analysis technology in geological and mineral survey, environmental pollution investigation, cultural relic identification, and alloy analysis are introduced.     

转小鼠金属硫蛋白(MT)基因烟草不同器官中金属离子铅和锌的分布

转金属硫蛋白(MT)基因植物具有清除重金属污染的能力,但是金属离子在植物体内的分布研究较少。文章以多代培育纯合的转MT烟草为材料,研究了转MT基因烟草积累铅和锌以及铅和锌在不同器官的分布情况。结果表明转基因植株的老叶、茎部和根部铅和锌积累量显著高于普通烟草植株,整株的铅和锌含量分别提高了21.8%和27.2%。铅和锌在植物体内的分布也发生了变化,转基因植株老叶和根中的铅含量分别高出普通烟草同位置的30.2%和47.8%,锌在转基因植株老叶、茎和根中的含量分别高出普通烟草同位置的44.7%,29.2%和21.6%,说明铅更容易在转基因植株老叶和根中积累,而锌更容易在转基因植株的老叶和茎中积累。     

原子吸收光谱法测定膜荚黄芪不同器官矿质元素含量

应用混合酸HNO₃-HClO₄ (4∶1) 在常压微沸条件下对膜荚黄芪根系及茎叶样品进行消解,采用原子吸收光谱法测定了膜荚黄芪不同器官即根及茎叶中五种人体必需矿质元素K,Fe,Zn,Mn和Cu含量,并对结果进行了统计分析与比较。该方法标准曲线相关系数为0.997 3～0.999 9, 加标回收率为92.88%～109.25%, 相对标准偏差(RSD,n=5) 为0.393 5%～3.175 2%。方法简单,结果可靠。结果显示,膜荚黄芪根及茎叶中5种矿质元素含量顺序均为K>Fe>Zn>Mn>Cu。膜荚黄芪不同器官矿质元素含量不同,根中富含Fe,Zn,Cu元素,根内Fe含量是茎叶的1.54倍。茎叶中也含有丰富的矿质元素,特别是K和Mn元素。茎叶中K含量是根的1.63倍,这与黄芪的药效相符合。试验结果将为研究矿质元素在黄芪植株中的分布以及矿质元素含量与黄芪药效相关性提供理论依据。     

ICP-AES法测定柚子不同部位中多种微量元素

采用电感耦合等离子体原子发射光谱法测定了柚子中多种微量元素,考查了广东、广西及赣州三种产地的柚子中15种元素的含量以及它们在果肉、表皮、内皮及籽中的分布情况。分析结果的相对标准偏差为0.4%～5.01%, 平均回收率在87.0%～115.0%之间。该方法简单、快速、可靠、灵敏度高,且多元素可同时测定,能满足实际样品分析要求。实验表明, 柚子中含有丰富的对人体有益的Ca,Mg,Fe,Zn,Mn,Cu和Na等元素, 相对有害元素Be,Pb,Bi,Cd和As含量很少。不同产地的柚子及柚子的不同部位其元素含量存在差异, 大部分元素在果肉中的含量相对柚子中其他部位的含量较低;B,Ba,Ca,Sr和Mn在果皮的含量总体相对高;Cu,Zn和Mg在籽中含量最高, 其中各元素在表皮与内皮中的含量差异不大。这种差异可能与植物生长的外在环境和土壤类型有关, 如土壤的pH值、本身所含的矿物质及后天灌溉所施肥料、水分等。用ICP-AES测定柚子中微量元素对此资源的充分利用具有重要的指导意义。     

IR spectroscopic methods for diagnosis of oncological pathologies in human tissues (Review)

Modern problems in the diagnosis of oncological pathologies using spectroscopic methods of analysis are considered. Fourier-transform IR spectroscopy methods are illustrated by investigation of tissues of breast, thyroid gland, stomach, kidney, lung, and skin excised during surgical intervention. IR spectra of surgical material are compared with data of histological analysis. Spectra of proteins and lipids in malignant neoplasms differ from those in benign tumors and in tissues beyond the pathological focus. Differences in protein spectra are attributed to changes in the supramolecular structure due to cleavage of intramolecular C=OH–N hydrogen bonds. Differences in IR spectra of lipids in neoplasms, when compared with those in normal tissues, are caused by changes in the structure of side chains of fatty-acid radicals appearing in malignant tumors. Spectral signatures of malignant pathology are revealed.