bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Properties of Novel 2,3-Dicyano-5-methyl-6H-1,4-diazepine Dyes in the Solid State
Authors: Horiguchi Emi , Matsumoto Shinya , Funabiki Kazumasa , Matsui Masaki 
Published: June 2005

Abstract
Novel nonplanar fluorescent dyes, 2,3-dicyano-7-methyl-6H-1,4-diazepines, were synthesized. The fluorescence intensity of 6-substituted 2,3-dicyano-5-[4-(diethylamino)styryl]-7-methyl-6H-1,4-diazepines in vapor-deposited film was on the order of the substituent at the 6-position: n-Bu, Et &gt; t-Bu, H. That of 2,3-dicyano-5-[4-(dialkylamino)styryl]-6-ethyl-7-methyl-6H-1,4-diazepines in the solid state was on the order of the alkyl group: CH2(3,5-(di-t-Bu)C6H3) &gt; Bn &gt; Et. Thus, the fluorescence intensity in the solid state basically increased with the bulkiness of the substituents on the chromophoric system. X-ray structure analysis clearly showed that the substituent at the 6-position and the dialkylamino moiety should inhibit intermolecular interactions between the chromophores so as to enhance the fluorescence intensity in the solid state.
High-Performance of PVK-based Photorefractive Polymers by High-Temperature Casting
Authors: Tanaka Shin-ya , Horikawa Hiroshi , Komori Yasushi , Nagayama Norio , Yokoyama Masaaki 
Published: June 2005

Abstract
To achieve high performance in molecularly dispersed photorefractive polymer films, it is essential to have a large electro-optic coefficient (r33), which is obtained by orientating nonlinear optic (NLO) molecules in an external electric field applied across the film. We investigated high-temperature casting, which is a new material fabrication technique for this purpose. We found that samples prepared by casting at higher temperatures showed a larger value of r33, which was due to an increasing number of unpaired NLO molecules in the polymer matrix that were able to orientate in an external electric field. This was caused by releasing stable anti-parallel pairs that were formed between the NLO molecules due to their large dipole moment. Therefore, our samples showed a large improvement in their photorefractivity in four-wave mixing (FWM) experiments.
The Non-Rigid Group of Tetraamine Platinum(II) as a Wreath Product
Authors: Darafsheh M R , Farjami Y , Ashrafi A R 
Published: June 2005

Abstract
A non-rigid molecule group theory (NRG) in which the dynamical symmetry operations are defined as physical operations is a new field of chemistry. Balasubramanian, Smeyers, and Villa in a series of papers applied this notion to determine the character table of restricted NRG (r-NRG) of some molecules. For example, Balasubramanian computed the NRG of the triple equivalent nitro group rotation in 1,3,5-triamino-2,4,6-trinitrobenzene, and proved that the NRG of this molecule is a group of order 48 (see Chem. Phys. Lett., 398, 15 (2004)). In this work a theoretical method is described for calculating the symmetry group of non-rigid molecules consisting of a number of XYn (n = 2,3,...) groups attached to a rigid framework. The non-rigid group of the molecule is a wreath product of symmetry group of the rigid frame with the permutation group of the XYn group. This algebraic structure of NRG helps us to compute the classes and character tables using the GAP package, even for large groups. We apply this method to find the structure of the non-rigid group of tetraamine platinum(II) with the D2d ordinary point group. It has proved that this is a group of order 5184. The method can be generalized to apply to other non-rigid molecules.
Application of N,N,N′,N′-Tetrasubstituted 1,3-Bis(4-aminophenyl)azulenes to Hole-injecting Materials for Durable Organic EL Devices without Color Fade
Authors: Oda Mitsunori , Thanh Nguyen Chung , Ikai Masamichi , Kajioka Takanori , Fujikawa Hisayoshi , Taga Yasunori , Ogawa Satoru , Shimada Hiroko , Kuroda Shigeyasu 
Published: June 2005

Abstract
The title 1,3-bis(aminophenyl)azulenes were synthesized from 1,3-dihaloazulene in two steps involving the Suzuki cross-coupling with 4-bromophenylboronic acid and subsequent Pd-catalyzed amination. Their HOMO energy levels were estimated to be comparable to that of the widely used hole-injecting (HI) material, copper phthalocyanine. The application of these diamines to HL materials in organic electroluminescent (EL) devices was also studied as non-cyanine and non-polyamine substance.
Sesquiterpene Esters from the Fruits of Celastrus orbiculatus
Authors: Guo Yuanqiang , Li Xian , Xu Jing , Meng Dali , Li Yushan , Ohizumi Yasushi 
Published: June 2005

Abstract
Two new β-dihydroagarofuran sesquiterpene esters, 1β,2β,6α-triacetoxy-9α-cinnamoyloxy-β-dihydroagarofuran (1) and 1β,8β-diacetoxy-9β-cinnamoyloxy-2β-hexanoyloxy-β-dihydroagarofuran (2), and four known compounds (3–6) have been isolated from the fruits of Celastrus orbiculatus Thunb. Their structures were elucidated on the basis of spectroscopic data. In murine macrophage RAW264.7 cells, compounds 2 and 6 inhibited LPS-induced nitric oxide production with the IC50 values of 67.3 μM and 63.5 μM, respectively.
Regioregular Poly(p-alkoxyphenylene)s Prepared from Facile Solid-state Oxidative Coupling Polymerization
Authors: Bai Wei Bin , Zhan Cai Mao 
Published: June 2005

Abstract
By grinding 1,4-dialkoxybenzene with anhydrous FeCl3 powder using a glass pestle in a mortar at ambient and solvent-free condition, poly(p-phenylene)s (PPP) was obtained in high yield up to 90% in 30 min. The products were characterized by 1H NMR, 13C NMR, WAXD, and UV–vis and the regioregular structure was suggested. The solid-state oxidative coupling polymerization is a facile, time saving, “green-chemistry” method.
Simple and Efficient Ratiometric Fluorescent Probes for Near-neutral pH in Aqueous Solutions
Authors: Xiang Yu , Tong Ai-Jun 
Published: June 2005

Abstract
Two ratiometric fluorescent pH probes of 2,6-diaminopyridine (DAPD) and 2-amino-5,7-dimethyl-1,8-naphthyridine (ADMND), though simple-structured, show good sensitivity to near-neutral pH range (6.0–8.0) in aqueous solutions. Further studies indicate that the 2-amino groups on pyridine or naphthyridine ring play an important role in the pH-dependent fluorescence spectral properties of these dyes.
Effects of Anion Species on Deintercalation of Carbonate Ions from Hydrotalcite-like Compounds
Authors: Iyi Nobuo , Okamoto Kentaro , Kaneko Yoshiro , Matsumoto Taki 
Published: June 2005

Abstract
The deintercalation of carbonate ions from a hydrotalcite-like compound (MgAl-LDH) was investigated using salt-HCl mixed solutions with sodium salts containing various monovalent anion species. The deintercalation was influenced by the anion species, and the carbonate ions were deintercalated most easily for the system containing Cl− or Br− anions.
Nearly Isotropic Two-dimensional Sheets in a Partially Oxidized Co(Pc)(CN)2 Salt (Pc = phthalocyaninato)
Authors: Asari Takehiro , Ishikawa Manabu , Naito Toshio , Matsuda Masaki , Tajima Hiroyuki , Inabe Tamotsu 
Published: June 2005

Abstract
Nearly isotropic two-dimensional sheets of partially oxidized Co(Pc)(CN)2 units were observed to form in a salt with PXX (PXX = peri-xanthenoxanthene), [PXX]2[Co(Pc)(CN)2]·CH3CN. The crystal is semiconducting under ambient pressure but displays stable metallic behavior under high pressure.
Molecular Orientation of Self-assembled Monolayer of Octadecanethiol on Platinum Surface Studied by Femtosecond Broad-bandwidth Sum Frequency Generation Spectroscopy
Authors: Noguchi Hidenori , Ito Mikio , Uosaki Kohei 
Published: June 2005

Abstract
The molecular orientation in self-assembled monolayer (SAM) of octadecanethiol (ODT) on platinum surface prepared in ethanol solution was examined by broad-bandwidth sum frequency generation (BB-SFG) spectroscopy. The bands attributed to the CH3 symmetric and asymmetric stretching vibrational modes were observed in the SFG spectra. From the analysis of SFG intensity ratio of these two modes, the alkyl chain on platinum was found to be more perpendicular to the substrate than those on gold surface.
Silica Nanobeads-decorated Multi-walled Carbon Nanotubes by Vapor-phase Method
Authors: Fan Wugang , Gao Lian 
Published: June 2005

Abstract
We report a new concise route to prepare carbon nanotube–silica nanobeads composites. The assembly of silica beads and nanotube by vapor-phase method make these structures an excellent platform for the development of biosensors, or for optical, magnetic and catalytic applications.
Highly Enantioselective (S)-Homoproline-catalyzed Michael Addition Reactions of Ketones to β-Nitrostyrenes
Authors: Terakado Dai , Takano Masako , Oriyama Takeshi 
Published: June 2005

Abstract
Being catalyzed by (S)-homoproline a highly enantioselective organocatalytic Michael addition reaction of ketones to β-nitrostyrenes has been achieved.
Hydrothermal Synthesis of Highly Ordered Micropompon of Lanthanum Molybdate Nanoflakes
Authors: Xu Yun-Peng , Jiang Dan-Yu , Bu Wen-Bo , Shi Jian-Lin 
Published: June 2005

Abstract
A novel micrometer-scale spherical structure composed of nanoflakes, named micropompon, has been achieved in the La2(MoO4)3 system through a simple surfactant-free hydrothermal approach. Possible formation mechanisms for the nanoflakes and micropompons have been preliminarily discussed.
The seven E. coli ribosomal RNA operon upstream regulatory regions differ in structure and transcription factor binding efficiencies
Authors: Hillebrand Annette , Wurm Reinhild , Menzel Artur , Wagner Rolf 
Published: June 2005

AbstractRibosomal RNAs inE. coliare transcribed from seven operons, which are highly conserved in their organization and sequence. However, the upstream regulatory DNA regions differ considerably, suggesting differences in regulation. We have therefore analyzed the conformation of all seven DNA elements located upstream of the majorE. colirRNA P1 promoters. As judged by temperature-dependent gel electrophoresis with isolated DNA fragments comprising the individual P1 promoters and the complete upstream regulatory regions, all seven rRNA upstream sequences are intrinsically curved. The degree of intrinsic curvature was highest for therrnBandrrnDfragments and less pronounced for therrnAandrrnEoperons. Comparison of the experimentally determined differences in curvature with programs for the prediction of DNA conformation revealed a generally high degree of conformity. Moreover, the analysis showed that the center of curvature is located at about the same position in all fragments. The different upstream regions were analyzed for their capacity to bind the transcription factors FIS and H-NS, which are known as antagonists in the regulation of rRNA synthesis. Gel retardation experiments revealed that both proteins interact with the upstream promoter regions of all seven rDNA fragments, with the affinities of the different DNA fragments for FIS and H-NS and the structure of the resulting complexes deviating considerably. FIS binding was non-cooperative, and at comparable protein concentrations the occupancy of the different DNA fragments varied between two and four binding sites. In contrast, H-NS was shown to bind cooperatively and intermediate states of occupancy could not be resolved for each fragment. The different gel electrophoretic mobilities of the individual DNA/protein complexes indicate variable structures and topologies of the upstream activating sequence regulatory complexes. Our results are highly suggestive of differential regulation of the individual rRNA operons.
Assembly of natural and recombinant prion protein into fibrils
Authors: Leffers Karl-Werner , Wille Holger , Stöhr Jan , Junger Erika , Prusiner Stanley B. , Riesner Detlev 
Published: June 2005

AbstractThe conversion of the α-helical, cellular isoform of the prion protein (PrPC) to the insoluble, β-sheet-rich, infectious, disease-causing isoform (PrPSc) is the fundamental event in the prion diseases. The C-terminal fragment of PrPSc(PrP 27–30) is formed by limited proteolysis and retains infectivity. Unlike full-length PrPSc, PrP 27–30 polymerizes into rod-shaped structures with the ultra-structural and tinctorial properties of amyloid. To study the folding of PrP, both with respect to the formation of PrPScfrom PrPCand the assembly of rods from PrP 27–30, we solubilized Syrian hamster (sol SHa) PrP 27–30 in low concentrations (0.2%) of sodium dodecyl sulfate (SDS) under conditions previously used to study the structural transitions of this protein. Sol SHaPrP 27–30 adopted a β-sheet-rich structure at SDS concentrations between 0.02% and 0.04% and remained soluble. Here we report that NaCl stabilizes SHaPrP 27–30 in a soluble, β-sheet-rich state that allows fibril assembly to proceed over several weeks. Under these conditions, fibril formation occurred not only with sol PrP 27–30, but also with native SHaPrPC. Addition of sphingolipids seems to increase fibril growth. When recombinant (rec) SHaPrP(90–231) was exposed to low concentrations of SDS, similar to those used to polymerize sol SHaPrP 27–30 in the presence of 250 mM NaCl, fibril formation occurred regularly. When fibrils formed from PrP 27–30 or PrPCwere bioassayed in transgenic mice overexpressing full-length SHaPrP, no infectivity was obtained, whereas amyloid fibrils formed of rec mouse PrP(89–230) were infectious. At present, it cannot be determined whether the lack of infectivity is caused by a difference in the structure of the fibrils or in the bioassay conditions.
Apolipoprotein A5 gene polymorphism –1131T→C: association with plasma lipids and type 2 diabetes mellitus with coronary heart disease in Chinese
Authors: Yan Sheng-Kai , Cheng Xin-Qi , Song Yao-Hong , Xiao Xin-Hua , Bi Nan , Chen Bao-Sheng 
Published: June 2005

AbstractType 2 diabetes mellitus (DM) is associated with significant abnormalities of lipoprotein metabolism and coronary heart disease (CHD). The most commonly recognized lipid abnormality in type 2 DM is hypertriglyceridemia, which is known to be an independent risk factor for CHD in diabetics. The –1131T→C polymorphism found in the newly identified apoli-poprotein A5 (
Plasma homocysteine and markers for oxidative stress and inflammation in patients with coronary artery disease – a prospective randomized study of vitamin supplementation
Authors: Jonasson Torfi , Öhlin Ann-Kristin , Gottsäter Anders , Hultberg Björn , Öhlin Hans 
Published: June 2005

AbstractBackground: Elevated plasma levels of total homocysteine (tHcy) are associated with an increased risk of developing occlusive vascular diseases. To better illustrate the relationship between plasma tHcy concentration, oxidative stress, and inflammation in patients with coronary artery disease (CAD), we measured plasma 8-isoprostane-prostaglandin FMethods: A total of 93 patients with ischemic heart disease were investigated. Of these, 34 had plasma tHcy ≤8μmol/L, while 59 had plasma tHcy ≥15.0 μmol/L. The 59 patients were randomized to open therapy with folic acid, 5mg, pyridoxine, 40mg, and cyancobalamin, 1mg once daily for 3months (n=29) or to no vitamin treatment (n=30). Blood samples were obtained from both groups before randomization and 3months later. A sample was also obtained from the remaining 34 patients.Results: Plasma Iso-P, serum amyloid A (S-AA), and plasma intercellular adhesion molecule-1 (ICAM-1) concentrations were higher in patients with high plasma tHcy levels than in patients with low to normal tHcy levels. Plasma levels of P-, L-, E-selectins, MDA, C-reactive protein (CRP), and orosomucoid did not differ between the groups. Vitamin therapy reduced plasma tHcy from 17.4 (15.3/20.1) to 9.2 (8.3/10.3)μmol/L (25th and 75th percentiles in parentheses) (p<0.0001). Plasma levels of Iso-P remained unchanged and, of all inflammatory markers, only the S-AA concentrations were slightly reduced by the vitamin treatment, from 5.3 (2.2/7.0)ng/L at baseline to 4.6 (2.1/6.9)ng/L (p<0.05) after 3months of vitamin supplementation.Conclusion: Patients with CAD and high plasma tHcy levels had elevated plasma levels of Iso-P. The increase remained unaffected by plasma tHcy-lowering therapy, suggesting that homocysteine per se does not cause increased lipid peroxidation. Levels of plasma ICAM-1 and S-AA were increased in patients with high plasma tHcy, suggesting an association between homocysteinemia and low-grade inflammation.
Comparison of methods for calculating serum osmolality: multivariate linear regression analysis
Authors: Rasouli Mehdi , Kalantari Kiarash Rezaei 
Published: June 2005

AbstractBackground: There are several methods for calculating serum osmolality, and their accordance with measured osmolality is the subject of controversy.Methods: The concentrations of sodium, potassium, glucose, blood urea nitrogen (BUN) and osmolalities of 210 serum samples were measured. Two empirical equations were deduced for the calculation of serum osmolality by regression analysis of the data. To choose the best equation, chemical concentrations were also used to calculate osmolalities according to our formulas and 16 different equations were taken from the literature and compared with the measured osmolalities. Correlation and linear regression analyses were performed using Excel and SPSS software.Results: Multiple linear regression analysis showed that serum concentrations of sodium (β=0.778, p≤0.000), BUN (β=0.315, p≤0.000), glucose (β=0.0.089, p≤0.007) and potassium (β=0.109, p≤0.008) are strong predictors of serum osmolality. The data were also analyzed by manual linear regression to yield the equations: osmolality=1.897[NaConclusions: Our data suggest use of the Worthley et al. formula Osm=2[Na
A guide to defining the competence required of a consultant in clinical chemistry and laboratory medicine
Authors: Beastall Graham , Kenny Desmond , Laitinen Paivi , ten Kate Joop 
Published: June 2005

AbstractA definition has been agreed for the most senior professional (consultant) in clinical chemistry and laboratory medicine. A model job description for a consultant has been determined, which is intended to act as a toolkit to assist employing authorities and professional bodies to define the role of individual consultant posts. A total of 86 competences for a consultant have been designated and expressed in the form of simple generic proficiency standards. These competences have been allocated to six broad areas: clinical [13]; scientific [15]; technical [12]; communication [12]; management and leadership [20]; professional autonomy and accountability [14]. The competences are intended to be illustrative rather than definitive and to enable the duties of any consultant post to be defined. Assessment of competence is likely to entail consideration of qualifications, registration status, continuing professional development and performance review. The project is intended as a guide to European societies of clinical chemistry and laboratory medicine. The guide should be capable of local interpretation to encourage a greater degree of commonality in the role of the consultant whilst protecting national identity. The guide should stimulate international understanding and collaboration and contribute to an overall improvement in the quality of practice.
Chemical changes in silver birch (Betula pendula Roth) wood caused by hydrogen peroxide bleaching and monitored by color measurement (CIELab) and UV-Vis, FTIR and UVRR spectroscopy
Authors: Mononen Kirsi , Jääskeläinen Anna-Stiina , Alvila Leila , Pakkanen Tuula T. , Vuorinen Tapani 
Published: June 2005

Abstract
Silver birch (Betula pendula Roth) wood was subjected to bleaching with acidic hydrogen peroxide solution. The color change and chemical changes occurring on bleaching were investigated by CIELab color measurements and UV-Vis, FTIR and UVRR spectroscopy. With bleaching, the color of birch wood changed notably towards white, less red and more yellow, revealed by the CIELab color measurements, however, followed by notable yellowing in 343 days. The chemical changes occurring with the bleaching treatment in the xylem of birch, demonstrated by UV-Vis, FTIR and UVRR spectroscopy, indicated degradation of aromatic structures with a simultaneous increase in relative amounts of unconjugated carbonyl structures. The results indicate that the degradation of aromatic structures involved opening of the aromatic ring possibly leading to the formation of muconic acids or other low molecular weight products rich in carbonyl structures. In addition, in birch wood subjected to bleaching treatment with acidic hydrogen peroxide solution, syringyl structures provided favorable sites for the degradation of aromatic structures.
Isolation and fractionation of lignosulfonates by amine extraction and ultrafiltration: A comparative study
Authors: Ringena Okko , Saake Bodo , Lehnen Ralph 
Published: June 2005

Abstract
Spent sulfite liquors (SSLs) were fractionated by two common separation techniques: amine extraction and ultrafiltration. The lignin fractions obtained were characterized with respect to their elemental composition, functional groups and molecular weight distribution. The results of size exclusion chromatography indicate a broad molecular weight distribution of the lignosulfonates (LS). Irrespective of the separation technique used, a small LS fraction with high molecular mass and low degree of sulfonation was obtained, while most of the lignosulfonates have much lower molar masses and a much higher degree of sulfonation. Both separation methods offer the opportunity to extract high-purity LS fractions; however, compared to amine extraction, ultrafiltration provides additional information about the molecular weight distribution of the SSL components without application of other analytical techniques.
X-ray scattering studies of thermally modified Scots pine (Pinus sylvestris L.)
Authors: Andersson Seppo , Serimaa Ritva , Väänänen Tiina , Paakkari Timo , Jämsä Saila , Viitaniemi Pertti 
Published: June 2005

AbstractWood is thermally modified by heating and steaming in order to change its properties, e.g., to improve the biological resistance and to increase the hardness of wood. The structure of thermally modified Scots pine (Pinus sylvestris) was studied using wide-angle, small-angle and ultra-small-angle X-ray scattering methods. Modification temperatures varied from 100 to 240°C. No marked changes in the microfibril angle distribution were observed. The mass fraction of crystalline cellulose in wood (the crystallinity of wood) and the size of cellulose crystallites increased above 150°C. After modification at 230°C for 4 h the thickness of the cellulose crystallites increased from 3.1 to 3.4 nm. Thermal modification had no effect on the orientation of the voids, but an increase in the porosity of the cell wall was observed. The distance between cellulose crystallites was approximately 4.7 nm in hydrated wood and a decrease in order between microfibrils was observed at 160–200°C.
Differences in acoustic velocity by resonance and transit-time methods in an anisotropic laminated wood medium
Authors: Chauhan Shakti Singh , Entwistle Kenneth M. , Walker John C.F. 
Published: June 2005

Abstract
The influence of inhomogeneity on acoustic velocity measured by a resonance-based WoodSpec acoustic tool and a transit-time-based Fakopp-2D tool was investigated. Four laminated panels with different degrees of inhomogeneity were prepared and acoustic velocities were measured using both tools. Velocities measured by the Fakopp-2D tool were always higher than those measured by the WoodSpec tool in all panels. The difference in the two velocities was found to vary depending on the magnitude of inhomogeneity. It was demonstrated that the velocity measured by the resonance frequency obeys the law of mixtures and is controlled by the volume-weighted average stiffness of the material. In contrast, the velocity measured by the Fakopp-2D tool was the velocity of the pulse that first reached the detector travelling at the dilatational speed.