Structure of 1,2,4-oxadiazolidine-3,5-dione monohydrate

C2H2N203.H20, Mr= 120.07, monoclinic,P21/c, a= 5.011 (1), b= 11.796(2), c= 7.689 (2)A,fl= 95.22 (2) ° , V= 452.61 A 3, Z= 4, Dx= 1.76, D m = 1.75 gcm -3, /].(Cu Ks) = 1.5418 A, g = 14-0 cm -l,F(000) = 248, T = 293 K, crystal quality was poor and the final R =0.107, wR =0.090 for 881 observed reflections. The compound is derived from a novel form of the monopropellant oxalohydroxamic acid. The two exocyclic C-O bond lengths of 1.240 (3) and 1.228 (4)A indicate double bonds. The C-N bond lengths of 1.334 (4), 1.390 (4) and 1.359 (4) A are characteristic of the amide bond. The N atom covalently bonded to the two carbonyl C atoms acts as a proton donor in an intermolecular hydrogen bond to the ring O atom: N1...O3i = 2.854 ]k (i =x-- 1,y, z), H...O = 2.15 A, N-H...O = 159 °.

量子链和量子点光学特性的比较研究

比较研究了InGaAs/GaAs量子链和量子点的稳态和瞬态光学特性.实验发现,量子链的荧光寿命有很强的探测能量依赖关系,而量子点的荧光寿命随能量变化较小;量子链的荧光寿命随着激发功率迅速增加,高功率时趋于饱和,而量子点的荧光寿命随激发功率变化缓慢;此外,量子链样品的荧光上升时间也比量子点的小得多.这些结果清楚表明,在量子链结构中,参与发光的载流子之间存在很强的耦合和输运.进一步分析表明,这种耦合作用主要发生在量子链方向.荧光的偏振特性进一步证实了这一点.

InGaAs/GaAs量子链的光学特性研究

研究了InGaAs/GaAs量子链的稳态和瞬态光谱特性,特别是载流子的动力学过程.实验发现荧光寿命有很强的探测能量依赖关系,荧光寿命随发光能量的增加而减小;实验还发现,当激发功率较小时,荧光寿命随激发功率增大而增大,当激发功率足够大时,荧光寿命趋于饱和.这些结果清楚地表明,在量子链结构中,参与发光的载流子之间存在明显的耦合和输运现象,进一步分析表明,这种输运主要是由于载流子沿量子链方向的耦合造成的.发光的偏振特性研究进一步证实了载流子沿量子链方向输运过程.

The extreme-ultraviolet structure and properties of a newly emerged active region

The structure and properties of a newly emerged solar active region (NOAA Active Region 7985) are discussed using the Coronal Diagnostic Spectrometer (CDS) and the Extreme- Ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory. CDS obtained high-resolution EUV spectra in the 308-381 Angstrom and 513-633 Angstrom wavelength ranges, while EIT recorded full-disk EUV images in the He II (304 Angstrom), Fe IX/X (171 Angstrom), Fe xii (195 Angstrom), and Fe XV (284 Angstrom) bandpasses. Electron density measurements from Si rx, Si X, Fe xii, Fe XIII, and Fe xiv line ratios indicate that the region consists of a central high- density core with peak densities of the order of 1.2 x 10(10) cm(-3), which decrease monotonically to similar to5.0 X 10(8) cm(-3) at the active region boundary. The derived electron densities also vary systematically with temperature. Electron pressures as a function of both active region position and temperature were estimated using the derived electron densities and ion formation temperatures, and the constant pressure assumption was found to be an unrealistic simplification. Indeed, the active region is found to have a high-pressure core (1.3 x 10(16) cm(-3) K) that falls to 6.0 x 10(14) cm(-3) K just outside the region. CDS line ratios from different ionization stages of iron, specifically Fe xvi (335.4 Angstrom) and Fe xiv (334.4 Angstrom), were used to diagnose plasma temperatures within the active region. Using this method, peak temperatures of 2.1 x 10(6) K were identified. This is in good agreement with electron temperatures derived using EIT filter ratios and the two-temperature model of Zhang et al. The high- temperature emission is confined to the active region core, while emission from cooler (1-1.6) x 10(6) K lines originates in a system of loops visible in EIT 171 and 195 X images. Finally, the three-dimensional geometry of the active region is investigated using potential field extrapolations from a Kitt Peak magnetogram. The combination of EUV and magnetic field extrapolations extends the "core-halo" picture of active region structure to one in which the core is composed of a number of compact coronal loops that confine the hot, dense, high- pressure core plasma while the halo emission emerges from a system of cooler and more extended loops.

A note on ethnic return migration policy in Kazakhstan : changing priorities and a growing dilemma

This paper offers a brief analysis of the legal aspects of the ethnic return migration policy of Kazakhstan, a post-Soviet Central Asian state that has been active in seeking ties with its diaspora since independence. This paper examines the definition of oralman (repatriates) and the establishment of a quota on the number of Kazakh immigrants who are eligible for government funds to show how the rationale and preferences in repatriation policy have changed over the years. By focusing on changes in migration-related legislation in the late 2000s and early 2010s, the paper notes that two key goals of Kazakhstan’s migration policy are not necessarily consistent with each other: the promotion of an ethnically based nation-building project by encouraging the "return" of co-ethnics living abroad, and building a workforce that is best suited for the development of the state’s economy.

Micropartículas contendo nanopartículas de quitosana usando sulfato e genipina para liberação modificada da triancinolona: obtenção, caracterização e estudo em células tumorais

Chitosan is a polymer biocompatibility and biodegradability widely used in drug delivery systems. The co-crosslinking of chitosan with sodium sulfate and genipin, to form particulate systems is related of making them more resistant to acidic pH and to modulate the release kinetics for the oral route. Triamcinolone is a glucocorticoid with anti-inflammatory and immunosuppressive actions. The nanoparticles were prepared by co-crosslinking and characterized for particle size, PDI, zeta potential, crosslinking degree, encapsulation rate, morphology, infrared spectroscopy, thermal analysis, release kinetics and cells studies. The nanoparticles were prepared initially without genipin with sodium sulphate and the particles parameters were monitored in function of different ratio of drug / polymer, different concentrations of sodium sulfate and polysorbate 80 and the drip mode of crosslinkers on polymers. After optimizing conditions, the chosen system parameters without genipin included mean diameter of 312.20 ± 5.70 nm, PDI 0.342 ± 0.013 and zeta potential of 20.18 ± 2.28 mV. The genipin was introduced into the system analyzing different concentrations (0.5, 1.0 and 2.0 mM) and crosslinking times (3, 6, 12 and 24 h). Evaluating crosslinking time with genipin (0.5 mM) it was showed that varying the genipin reaction time the systems size ranged from 235.1 to 334.4 nm, the PDI from 0.321 to 0.392 and zeta potential 20.92 to 30.39 mV. The crosslinking degree that coud vary from 14 to 30 %. Nanoparticles without genipina, 6 h and 24 h crosslinking time were dried by spray-drying method. Analysis by scanning electron micrograph (SEM) revealed that the microparticles showed spherical morphology. The encapsulation rate was 75 ± 2.3 % using validated HPLC methodology. The infrared analysis showed chemical interactions between the components of the formulation. Thermal analysis showed that systems with a higher degree of crosslinking had a higher thermal stability. On release kinetics, increasing the degree of crosslinking was able to decrease the concentration and rate of release of triamcinolone. In studies with liver cancer cells (HepG2) and colon (HT-29), the microparticulate prepared with triamcinolone and 24 h of crosslinking with genipin showed a potential for antitumor activity in hepatic cell line HepG2. Therefore, a new delivery system for triamcinolone on polymeric nanoparticles of chitosan cocrosslinked with genipin and sodium sulfate was obtained with hepatic antitumor potential.

鸭催乳素基因外显子4单核苷酸多态性与就巢性状的相关分析

研究采用PCR-SSCP技术研究番鸭不同就巢群体(就巢1月群、就巢2月群、就巢3月群)、番鸭非就巢群和白改鸭5个群体250个个体PRL基因第4外显子多态性与就巢性状之间的相关性.结果表明,在外显子4编码区内发现2个SNP位点,分别位于该基因的3 777 bp (T/C)和3 785 bp(A/C)处.基因型与就巢性状指标相关分析的结果表明,番鸭非就巢群体与各就巢群体间差异极显著(P<0.01),同时番鸭与白改鸭差异显著(P<0.05),推测PRL基因与就巢性有一定的相关.

The antioxidant activity of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-di-sulfanimide)-chitosan

Chitosan (CS) with two different molecular weights was modified by reacting with 4-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride or 2-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride to give new 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-di-sulfanimide)-chitosan (2-HCBSAHCS, 2-HCBSALCS, 4-HCBSAHCS, 4-HCBSALCS). The structure of the derivatives was characterized by FT-IR and C-13 NMR spectroscopy. The antioxidant activities of the derivatives were investigated employing various established systems, such as hydroxyl radical ((OH)-O-center dot)/superoxide anion (O-2(radical anion)) scavenging/reducing power and chelating activity. All the derivatives showed stronger scavenging activity on hydroxyl radical than chitosan and ascorbic acid (Vc), and IC50 of 4-HCBSAHCS, 4-HCBSALCS, 2-HCBSAHCS and 2-HCBSALCS was 0.334, 0.302, 0.442, 0.346 mg/mL, respectively. The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were strong. The results showed that the superoxide radical scavenging effect of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-disulfanimide)-chitosan was higher than chitosan. The derivatives had obviously reducing power and slight chelating activity. The data obtained in in vitro models clearly establish the antioxidant potency of 2-(4(or 2)-hydroxyl-5-chloride-1,3-benzene-disulfanimide)-chitosan. (C) 2007 Elsevier Masson SAS. All rights reserved.

Sovereignty, Article 4(2) TEU and the Respect of National Identities: Swinging the Balance of Power in Favour of the Member States?

The question of whether and to what extent sovereignty has been transferred to the European Union (EU) from its Member States remains a central debate within the EU and is interlinked with issues such as Kompetenz-Kompetenz, direct effect and primacy. Central to any claim to sovereignty is the principle of primacy, which requires that Member States uphold EU law over national law where there is a conflict. However, limitations to primacy can traditionally be found in national jurisprudence and the Maastricht Treaty introduced a possible EU limitation with the requirement that the EU respect national identities of Member States. The Lisbon Treaty provided only minimal further support to the principle of primacy whilst simultaneously developing the provision on national identities, now found within Article 4(2) TEU. There are indications from the literature, national constitutional courts and the Court of Justice of the EU that the provision is gathering strength as a legal tool and is likely to have a wider scope than the text might indicate. In its new role, Article 4(2) TEU bolsters the Member States’ claim to sovereignty and the possibility to uphold aspects crucial to them in conflict with EU law and the principle of primacy. Consequently, it is central to the relationship between the constitutional courts of the Member States and the CJEU, and where the final elements of control remain in ‘hard cases’. However, it does so as part of EU law, thereby facilitating the evasion of direct fundamental conflicts and reflecting the concept of constitutional pluralism.

Photoswitches and Luminescent Rigidity Sensors Based on fac-[Re(CO)(3)(Me(4)phen)(L)](+)

The fac-[Re(CO)(3)(Me(4)phen)(trans-L)](+) complexes, Me(4)phen = 3,4,7,8-tetramethyl-1,10-phenanthroline and L = 4-styrylpyridine, stpy, or 1,2-bis(4-pyridyl)ethylene, bpe, were synthesized and characterized by their spectroscopic, photochemical, and photophysical properties. The complexes exhibit trans-to-cis isomerization upon 313, 334, 365, and 404 nm irradiation, and the true quantum yields can be efficiently determined by absorption changes combined with (1)H NMR data. For fac-[Re(CO)(3)(Me(4)phen)(trans-bpe)](+) similar quantum yields were determined at all wavelengths investigated. However, a lower value (phi(true) = 0.35) was determined for fac-[Re(CO)(3)(Me(4)phen)(trans-stpy)](+) at 404 nm irradiation, which indicates different pathways for the photoisomerization process. The photoproducts, fac-[Re(CO)(3)(Me(4)phen)(cis-L)](+), exhibit luminescence at room temperature with two maxima ascribed to the (3)IL(Me4phen) and (3)MLCT(Re -> Me4phen) excited states. The luminescence properties were investigated in different media, and the behavior in glassy EPA at 77 K showed that the contribution of each emissive state is dependent on the excitation wavelength. The photochemical and photophysical behavior of the complexes were rationalized in terms of the energy gap of excited states and can be exploited in photoswitchable luminescent rigidity sensors.