bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of 1,2,3-Naphthalenetriamine, 1,2,5,6- and 1,2,7,8-Naphthalenetetramine, and 5,6,7,8-Quinolinetetramine and -Isoquinolinetetramine by Reduction of the Fused 1,2,5-Thiadiazole Ring
Authors: Mataka Shuntaro , Ikezaki Youji , Takahashi Kazufumi , Tori-i Akiyoshi , Tashiro Masashi
Published: July 2006

The two fused 1,2,5-thiadiazole-rings of naphthalenes 1a and 1b, quinoline 2a, and isoquinoline 2b were reduced with tin and concentrated hydrochloric acid in refluxing dioxane, giving the expected 1,2,5,6-naphthalenetetramine (4a) and 1,2,7,8-tetramine derivative 4b, 5,6,7,8-quinolinetetramine (15a) and isoquinoline analogue 15b in moderate yields. Partially reduced diamine 5 was formed as a by-product in the reduction of 1a. The expected 1,2,3,4-naphthalenetetramine (4c) was not obtained in the reduction of 1c at room temperature and the 1,2,3-triamine 8 was formed in 27% yield. The intermediary formation of 4c was confirmed by acetylating the crude reduction mixture of 1c, giving tetraacetyl derivative 11. The reduction of naphthotris[1,2,5]thiadiazole 3 afforded 4,5-diamine 16 in 44% yield. Polyamines 4a–b, 8, 15a–b, and 16, were obtained as their hydrochloride(s).
Synthetic Study on Peptide Antibiotic Nisin. V. Total Synthesis of Nisin
Authors: Fukase Koichi , Kitazawa Manabu , Sano Akihiko , Shimbo Kuniaki , Horimoto Shingo , Fujita Hiroshi , Kubo Akira , Wakamiya Tateaki , Shiba Tetsuo
Published: July 2006

Total synthesis of a lanthionine peptide nisin was achieved by the successive condensations of four segments including cyclic lanthionine peptide parts and the C-terminal linear segment including dehydroalanine, followed by the deprotection procedure with anhydrous HF. Modified reaction conditions for the Hofmann degradation were applied to prepare the dehydroalanine residue from the 2,3-diaminopropionic acid residue. The final deprotection with anhydrous HF proceeded without decomposition of the dehydroamino acid residues which are generally labile in acidic media. The synthetic nisin was completely identical with the natural one in all respects, resulting in a confirmation of the proposed structure.
Oxidative Coupling of Methane over Various Barium Salts Mixed with CaO: The Relation with Their Surface Basicities
Authors: Yamagata Nobutsugu , Nakamura Kazuyoshi , Kimura Satoshi , Sasaki Shouich , Yamada Misako , Okazaki Susumu
Published: July 2006

Oxidative coupling of methane to ethane and ethylene was carried out over barium salts mixed with CaO catalysts prepared by a wet-mixing method. The mixing effect of the barium salts on the C2 yield at 800 °C was remarkable in the following order: BaBr2 > BaCl2 >> BaI2, Ba(OH)2, BaF2 > BaC2O4, Ba(NO3)2 > BaCO3, BaSO4 > Ba3(PO4)2( > CaO). The high C2 yield of the BaCl2/CaO catalysts was kept relatively long, and was nearly constant (19–20%) over a range of 5 to 30 mol% BaCl2. Measurements of the temperature-programmed desorption of the used barium salt/CaO catalysts showed that a catalyst with the high C2 selectivity and high C2 yield tended to have large CO2 desorption peaks at higher temperatures; they were also well-dispersed with barium ions. In the case of BaCl2/CaO catalysts (2.5–40 mol% BaCl2), a large desorption peak of CO2 was observed at around 730 °C, that was associated with their high C2 yields. The role of basic sites resulting from the desorption of CO2 is discussed.
Molecular Motions in Solid CD3NH3PbBr3 as Studied by 1H NMR
Authors: Xu Qiang , Eguchi Taro , Nakayama Hirokazu
Published: July 2006

The temperature dependence of the 1H spin-lattice relaxation times (T1) was measured through the successive phase transitions in solid CD3NH3PbBr3. The T1’s in the lowest-temperature phase (phase-III) have a single minimum at 30 K, indicating that CD3NH3+ undergoes a correlated C3-reorientation (Ea= 2.7 kJ mol−1) about the C–N axis. This fact clearly supports the previous assignment of the relaxation mechanism near 65 K in phase-III of CH3NH3PbBr3, where an uncorrelated C3-reorientation of the cations is excited (Ea= 7.5 kJ mol−1).
AM1 Potential Energy Curves for Cis–Trans Isomerization of Stilbene Cation Radicals
Authors: Kikuchi Osamu , Oshiyama Tomohiro , Takahashi Ohgi , Tokumaru Katsumi
Published: July 2006

AM1 potential energy curves of stilbene cation radical and its derivatives were calculated by the open-shell RHF methods as a function of the twist angle of the central C–C bond. The electronic properties of the potential energy curves of stilbene cation radicals were well understood, and the substitutent effect on the barrier height for the cis-trans isomerization was evaluated.
Synthesis and Photo Valence Isomerization of Polyamide Bearing Norbornadiene Unit
Authors: Kamogawa Hiroyoshi , Gochou Seigo , Nakahara Masatsugu
Published: July 2006

Polyamides bearing norbornadiene (NBD) unit were prepared by the reaction of either bis(p-nitrophenyl) 2,3-NBD-dicarboxylate or a mixed anhydride bearing at the NBD moiety with various diamines. Films made of the polyamides indicated reversible UV-spectrum changes with UV irradiation, suggesting the occurrence of the photo-valence isomerization between the NBD and quadricyclane units.
High Polariton Reflectance in Heptamethinebis(dimethylamino)cyanine Chloride Crystal
Authors: Daehne Lars , Kamiya Koji , Tanaka Jiro
Published: July 2006

The reflection spectra of single crystals of bis(dimethylamino)heptamethinium chloride were measured with polarized light in the region from 500 to 38000 cm−1. The Kramers Kronig transformation was calculated and the determined dielectric functions are discussed in terms of the polariton and molecular exciton theories. The highly anisotropic reflection band is caused by one narrow molecular transition, which is polarized parallel to the molecular chain. The bathochromic shift of the transition energy compared to the value in solution and the large splitting of transverse and longitudinal modes are explained by the molecular exciton theory. The expected charge resonance transition could not be found. That will be discussed in respect to the arrangement of the molecules in the crystal.
Thermodynamic Studies on the Complexation of o-Phenylenediamine-N,N,N′,N′-tetraacetate with Divalent Cadmium, Mercury, and Lead Ions in Aqueous Solutions
Authors: Azuma Shigeki , Nakasuka Noriyuki , Tanaka Motoharu
Published: July 2006

Potentiometric studies have been carried out on the complexation of o-phenylenediamine-N,N,N′,N′-tetraacetate (phdta, L4−) with the cadmium and lead ions (M2+) in aqueous solutions at 25 ± 0.1 °C and I = 1.00 M (NaClO4). The ligand buffer method was successfully applied to the determination of the formation constant (M2+ + L4− = ML2− : KML) by use of Cd and Pb ion-selective electrodes. This method gave log KML = 13.37 for CdL and 13.89 for PbL. Calorimetry and potentiometry gave the values of enthalpy and entropy of complexation (−ΔH°/ kJ mol−1 = 18.9, ΔS°/J K−1 mol−1 = 193 (CdL); 34.8, 149 (PbL); and 50.6, 165 (HgL), respectively). Thermodynamic parameters of the protonation to ML were also examined for the PhDTA complexes of these and some divalent transition metal ions. The metal complexes are classified into two categories according to the thermodynamic parameters: A) Mn2+, Cd2+, and Pb2+ (−ΔH°MHL = −1.1–1.1 kJ mol−1; ΔS°MHL = 43–49 J K−1 mol−1). B) Co2+, Ni2+, Cu2+, and Zn2+ (−ΔH°MHL = 8.0–11.3 kJ mol−1; ΔS°MHL = 18–37 J K−1 mol−1). The smaller value of −ΔH°MHL for A has been interpreted in terms of simple protonation to a carboxylate oxygen in the complex ML, with any acetate group not being dissociated. The entire process of protonation for B, however, may be composed of two steps: i) Detachment of one carboxylate group from the metal ion, followed by the hydration resulting in M(L′) (H2O)2−, where L′ represents a ligand anion with a free carboxylate group, ii) Protonation to an oxygen atom of the detached carboxylate group.
Analysis of Ortho Effects with a Steric Parameter Defined by the Acidic Hydrolysis Rate of Ortho-Substituted Benzamides
Authors: Sotomatsu Tomoko , Fujita Toshio
Published: July 2006

The applicability of our new steric parameter for ortho substituents, Es(AMD), in evaluation of organic reactivity and physicochemical data was examined. The Es(AMD) constant was derived from the rate constants for acidic hydrolysis of ortho-substituted benzamides, and its scale was put as close as possible to that of the Es steric parameter of Taft, and Kutter and Hansch (TKH). For alkyl and halogen substituents, the Es(AMD) value was very close to the TKH Es value, but for methoxyl, isopropoxyl, and such planar π-bonded substituents as NO2 and Ph, it was not. Reactivity and physicochemical data taken from the literature were analyzed quantitatively by use of steric and electronic parameters, and the results obtained by Es(AMD) and Es were compared. The Es(AMD) value gave better results than TKH Es in various reactions including those of benzoic acids and their derivatives, if the change in the hybridization geometry of the reaction center between the initial and intermediate states was similar to that of the reference reaction.
Effect of Two Electron-Donating Substituents on Photochromism of Aryl Fulgide, 2-(2,6-Dimethyl-3,5-substituted benzylidene)-3-isopropylidenesuccinic Anhydride
Authors: Tomoda Akihiko , Kaneko Akira , Tsuboi Hideki , Matsushima Ryouka
Published: July 2006

Two electron-donating substituents (e.g. p-diethylaminostyryl) were introduced to an aryl structure of fulgide and photochromic performance was investigated. It was found that the strong electron-donating ability of the substituents caused a significant red shift of the colored form to the near-infrared region (λmax; 633 nm), resulting in a high molecular extinction coefficient (εmax; 24300 mol−1 cm−1). Furthermore, rapid reactions of both coloration and discoloration were observed; the quantum yields (φEC and φCE) were 0.65 and 0.052, respectively.
An Efficient and Practical Synthesis of l-α-Amino Acids Using (R)-Phenylglycinol as a Chiral Auxiliary
Authors: Inaba Takashi , Kozono Ichiro , Fujita Makoto , Ogura Katsuyuki
Published: July 2006

l-α-Amino acids including l-α-arylglycines were conveniently and stereoselectively synthesized via the α-amino carbonitriles given by the Strecker reaction of (R)-2-amino-2-phenylethanol with aldehydes and hydrogen cyanide. The stereoselectivity of these α-amino carbonitriles was thermodynamically controlled.
Synthesis of Non-Ester Pyrethroids Having a 1-Fluoro-1-methylethyl Group Using 1,2-Migration of an Aryl Group
Authors: Uneme Hideki , Okada Yoshiyuki
Published: July 2006

When 1,4-diaryl-4-methyl-1,3-pentanediol was treated with diethylaminosulfur trifluoride to introduce fluorine atoms into the central link, 1,2-aryl group migration products which have a 1-fluoro-1-methylethyl group were obtained as two diastereomers. Utilizing this migration, some non-ester pyrethroids possessing a 1-fluoro-1-methylethyl group were prepared. The reactivity of other fluorinating reagents is also discussed.
A Novel Synthesis of Allenic Lactones by Use of the [2,3]Sigmatropic Rearrangement of Cyclic Propargylsulfonium Ylides
Authors: Kido Fusao , Abiko Toshiya , Kato Michiharu
Published: July 2006

The [2,3]sigmatropic rearrangement of the cyclic propargylsulfonium ylides generated from ethyl 5-phenylthio-3-pentynyl and ethyl 6-phenylthio-4-hexynyl diazomalonates provided the novel allenic lactones, 2-ethoxycarbonyl-2-phenylthio-3-vinylidene-5-pentanolide and 6-hexanolide, respectively.
cis- and trans-Li[CoIII{l-tart(2–)-O1}2(en)2] Hydrate Separated from the Reaction Products of [CoIII(CO3)(en)2]+ with l-Tartaric Acid
Authors: Tomizawa Hiroshi , Harada Kazumasa , Miki Eiichi , Mizumachi Kunihiko , Ishimori Tatsujiro , Nakahara Masayoshi
Published: July 2006

The title compounds, trans(1) and cis(2) isomers, were isolated by means of QAE-Sephadex A-25 column chromatography from a reaction mixture of [Co(CO3)(en)2]Cl with l-tartaric acid. The crystal structure of 1 was determined by the X-ray diffraction study. The crystal is orthorhombic, space group C2221 with a = 12.008(1), b = 9.496(2), c = 18.524(4) Å, U = 2112.2(7) Å3, Z = 4, and final R = 0.0291. The two tartrate(2–) anions coordinate to the cobalt atom as a unidentate ligand in trans position each other. The two ethylenediamine rings are in the δδ gauche conformation. The lithium ion is tetrahedrally surrounded by two carboxylate oxygens of the tartrato(2–) ligands and two oxygens of the crystal waters. The compounds 1 and 2 were also characterized by UV-vis, NMR, and CD spectra.
Peroxidase-Catalyzed Chemiluminescence-Delay of Luminol for Determination of Traces of Copper(II)
Authors: Katayama Atsushi , Kamidate Tamio , Watanabe Hiroto
Published: July 2006

Delayed chemiluminescence (CL) was observed in the copper(II)-catalyzed oxidation of cysteamine with oxygen in the presence of horseradish peroxidase (HRP) and luminol. After preferential catalytic oxidation of cysteamine by both Cu(II) and HRP, a HRP-catalyzed luminol CL reaction was subsequently commenced with hydrogen peroxide accumulated from the catalytic oxidation. Thus, a delay time from the reaction initiation to a sharp flash of CL was observed. The HRP-catalyzed CL-delay of luminol was applied to the determination of Cu(II). The delay time was linearly correlated with the Cu(II) concentration over the range from the detection limit of 5.0 × 10−9 to 1.5 × 10−5 M. The detection limit of the present method is a factor of 30 times better than that of the conventional luminol CL method. The relative standard deviation of the delay time in five successive experiments was 3.2% at 1.0 × 10−7 M of Cu(II). The present method was highly sensitive compared to the conventional luminol CL method.
ESR Study of Active Oxygen Radicals from Photoexcited Semiconductors Using the Spin-Trapping Technique
Authors: Noda Hiroyuki , Oikawa Kazuo , Kamada Hitoshi
Published: July 2006

The ESR spin-trapping technique was used to detect active oxygen radicals by photoexcitation of powdery semiconductors (TiO2, WO3, CdS, and Fe2O3) in water and aqueous H2O2 solutions using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as spin trap. Superoxide ion (O2−), hydroperoxyl radical (·O2H) and hydroxyl radical (·OH) were detected under photoexcitation. The mechanism for the generation of active oxygen radicals is discussed referring to the energy band structures of the semiconductors and the redox potentials of the oxygen radicals.
Intercalation of a Trimethylammoniomethylated Calix[4]arene by Cu(II)-Montmorillonite
Authors: Kijima Tsuyoshi , Ohe Kaoru , Shinkai Seiji , Nagasaki Takeshi
Published: July 2006

The uptake of 5,11,17,23-tetrakis(trimethylammoniomethyl)-25,26,27,28-tetramethoxycalix[4]arene tetrachloride by Cu(II)-montmorillonite was examined at 25 °C. The mineral forms an intercalated phase in which the calixarene molecules are arranged as a 9.5 Å thick monolayer, with a cone-type conformation, with their cavity axes perpendicular to the silicate layers. Thermogravimetric and copper(II) release data suggest that the guest molecules are taken up in their tetra- and tri-valent forms during the initial and final uptake stages, respectively.
Synthesis, Characterization, and Properties of VIVO–Ln(III) (Ln = La, Pr, Eu, Gd, Tb) Complexes of N,N′-Bis(3-carboxysalicylidene)ethylenediamine
Authors: Sakamoto Masatomi , Ohsaki Masami , Yamamoto Koji , Nakayama Yusuke , Matsumoto Akira , Okawa Hisashi
Published: July 2006

Mononuclear oxovanadium(IV) and europium(III) complexes, [VO(H2fsaen)]·2H2O and [Eu(H2fsaen)(NO3)(H2On]·(5−n)H2O, and dinuclear oxovanadium(IV)–rare earth(III) complexes, [VOLn(fsaen)(NO3)(H2O)n]·(m−n)H2O (Ln = La, Pr, Eu, Gd, Tb), of N,N′-bis(3-carboxysalicylidene)ethylenediamine (H4fsaen) have been synthesized. Oxovanadium(IV) ion and europium(III) ion in the respective mononuclear complexes is bound at the O4-site of ligand, whereas in the VIVO–Ln(III) complexes VIVO ion is bound at the N2O2-site and Ln(III) ion at the O4-site. Based on the absorption and CD spectra, it is suggested that amino alcohols are specifically bound at the VIVO–Ln(III) heterometal center, through the nitrogen to the VIVO and through the oxygen to the Ln(III). The fluorescent spectral measurements reveal that the fluorescent bands of Eu(III) for the mononuclear Eu(III) complex are significantly quenched in the dinuclear VIVO–Eu(III) complex.
Vibrational and Rotational Raman Spectra of Trapped Hydrogen in Irradiated Ethanol Crystal at 77 K
Authors: Hase Hirotomo , Ishioka Kunie , Miyatake Yoko
Published: July 2006

Trapped hydrogen molecules were produced in γ-irradiated ethanol crystal at 77 K and their Raman spectra of Q- and S-branches were observed at 77 K for the first time. Relative scattering intensities of the bands due to p-H2 (Q1 (0), S0 (0)) and o-H2 (Q1(1)), S0(1)) were measured and compared with the reported results of solid normal hydrogen.
Halogenation Using Quaternary Ammonium Polyhalides. XXXII. Dichlorination of Aromatic Acetyl Derivatives with Benzyltrimethylammonium Tetrachloroiodate
Authors: Kakinami Takaaki , Urabe Yasuaki , Hermawan Irwan , Yamanishi Hiroko , Okamoto Tsuyoshi , Kajigaeshi Shoji
Published: July 2006

The reaction of aromatic acetyl derivatives with 2 molar amounts of benzyltrimethylammonium tetrachloroiodate in acetic acid at 70 °C for several hours gave dichloroacetyl derivatives in good yields.
Triphenylselenonium Salts as Effective Phase-Transfer Catalysts
Authors: Kondo Shuji , Shibata Akihiro , Kunisada Hideo , Yuki Yasuo
Published: July 2006

Triphenylselenonium salts work as highly efficient phase-transfer catalysts for nucleophilic substitution reaction of octyl bromide and addition reaction of dichlorocarbene to olefins.
Effects of Pd Dispersion on the Catalytic Activity of Pd/SiO2 for Ethylene Hydroformylation
Authors: Takahashi Nobuo , Tobise Tatsushi , Mogi Isao , Sasaki Makoto , Mijin Akihiko , Fujimoto Toshiyuki , Ichikawa Masaru
Published: July 2006

In ethylene hydroformylation over Pd/SiO2 catalysts with 17–85% Pd-dispersion, the turnover frequency for propionaldehyde formation increased with the Pd dispersion, particularly in the region of higher dispersion, suggesting the responsibility of atoms at the corners and at edges on the surface of Pd metal particles for this reaction.
Heterogeneous Amine Catalyst Grafted on Amorphous Silica: An Effective Organocatalyst for Microwave-promoted Michael Reaction of 1,3-Dicarbonyl Compounds in Water
Authors: Hagiwara Hisahiro , Inotsume Sachiyo , Fukushima Masakazu , Hoshi Takashi , Suzuki Toshio
Published: July 2006

Michael addition of a 1,3-dicarbonyl compound to an α,β-unsaturated carbonyl compound was effectively catalyzed by heterogeneous N,N-diethylaminopropylated silica gel (NDEAP) in water under microwave heating. The reaction condition was mild, practical, and environmentally benign. The sustainable nature of the catalyst was exemplified by re-use up to 5 times.
Mesophase Control of Mesoporous Silica Thin Films by Vapor-phase Preparation
Authors: Tanaka Shunsuke , Hillhouse Hugh W
Published: July 2006

Highly ordered mesoporous silica thin films with c2mm rectangular and R3m rhombohedral symmetry have been synthesized on a silicon substrate by a vapor-phase method using PEO106–PPO70–PEO106 triblock copolymer as a templating agent.
Oligonucleotide-bound Eu(III) as a Probe for Microenvironments at Specific Site in DNA
Authors: Sumaoka Jun , Kojima Yuki , Komiyama Makoto
Published: July 2006

By attaching Eu(III)/β-diketone complex covalently to oligonucleotide, microenvironments at a specific site in DNA have been probed. The conjugate efficiently emits luminescence, since coordination of water to the Eu(III) is competitively inhibited by the internal phosphodiester groups. In the presence of complementary DNA, however, this inhibition is diminished because of rigidity of double-stranded DNA and the emission becomes much weaker. The emission intensity is also affected by other environmental changes.
Modification of Highly Dispersed Cerium Oxides on Silica with Highly Dispersed Titanium Oxides as a New Photocatalyst Design for Nonoxidative Direct Methane Coupling
Authors: Yuliati Leny , Itoh Hideaki , Yoshida Hisao
Published: July 2006

Modification of ceria-based photocatalyst with titanium oxide resulted in formation of highly dispersed cerium and titanium oxides on silica, where both species exhibited photoactivities for nonoxidative direct methane coupling. A new design of photocatalyst was proposed here.
Photoinduced Release of Fluorescent Probe in the Presence of Target DNA: Synergetic Effect of Two Types of Oligonucleotides with Indolequinone–Coumarin Conjugate and Flavin Photosensitizer
Authors: Tanabe Kazuhito , Tachi Yukihiro , Okazaki Arimichi , Nishimoto Sei-ichi
Published: July 2006

We have synthesized and evaluated two types of functionalized oligodeoxynucleotides (ODNs) that can release a fluorescent coumarin probe via co-hybridization with a target DNA base sequence and subsequent photoirradiation. Photoirradiation of flavin-bearing ODN in the presence of a counterpart ODN with indolequinone–coumarin conjugate and a target complementary DNA strand gave rise to the efficient release of coumarin with a multiple turnover as a result of intermolecular flavin-photosensitized reduction of indolequinone–coumarin conjugate, while the release of coumarin was considerably suppressed in the absence of the target DNA. Concomitant with this photoreaction, we could observe intense fluorescence emission from the sample solution photoirradiated with the target DNA, but weak fluorescence from a control solution without the target DNA.
Synthesis and Characterization of Dimetallostannafluorenes
Authors: Saito Masaichi , Shimosawa Masakazu , Yoshioka Michikazu , Ishimura Kazuya , Nagase Shigeru
Published: July 2006

The reaction of 9,9-bis(p-methoxyphenyl)-9-stannafluorene with lithium or potassium gave the corresponding dimetallostannafluorene, as evidenced by NMR spectral analysis and a trapping experiment.
Self-assemblage of Single/Multiwall Hollow CeO2 Microspheres through Hydrothermal Method
Authors: Zhang Youjin , Hu Qixiu , Fang Zhiyong , Cheng Tao , Han Kaidong , Yang Xiaozhi
Published: July 2006

Novel single/multiwall hollow CeO2 microspheres were synthesized by self assemblage through hydrothermal method without any surfactant, the shells of which were consisted of CeO2 nanoparticles with mean size of 70 nm. The influence of the molar ratio of urea to Ce(NO3)3·6H2O on the morphology of the products was investigated and the formation mechanism of single/multiwall hollow CeO2 was proposed.
Approaches to rotary molecular motors
Authors: Hawthorne M. Frederick , Ramachandran Bhaskar M. , Kennedy Robert D. , Knobler Carolyn B.
Published: July 2006

Interest has recently intensified in the search for molecular motors and actuators capable of delivering useful work to nanodevices under the control of electrochemical or photochemical power sources. While many of these man-made molecular machines are designed to deliver rectilinear motion, very few are proposed for the controlled delivery of rotary motion on the time scale characteristic of intramolecular rearrangements. The adaptation of commo-bis-dicarbollide metallacarborane structures to the possible design and synthesis of such rotary molecular motors is now under investigation. Progress toward this goal will be reported.
Syntheses and chemistry of bis- and tris-mercaptoborates
Authors: Shore Sheldon G. , Hamilton Ewan J. M. , Kultyshev Roman G. , Leung Hoitung T. , Yisgedu Teshome
Published: July 2006

The preparation and chemistry of bis- and tris-mercaptoborates based on closo-B12 and closo-B10 structures is described. These species undergo a number of reactions such as halogenation and alkylation without changing the closo-borane core. Addition of the third dimethylsulfide substituent to the closo-boranes is thought to proceed via an unusual cationic intermediate.
Recent developments in the chiral synthesis of homoallylic amines via organoboranes
Authors: Ramachandran P. Veeraraghavan , Burghardt Thomas E.
Published: July 2006

Among the plethora of protocols for the preparation of chiral homoallylic amines, the use of boron-based reagents remains relatively undeveloped. However, the recent advances in the use of α-pinene-based versatile reagents for the synthesis of such amines confirmed that very high enantioselectivity and outstanding diastereoselectivity can be readily achieved. Addition of the "allyl"boron reagents to various N-substituted imines provided the desired amine products in high yields and high to very high ee. The discovery that an addition of 1.0 equiv of methanol or water to the "allyl"boration reaction with N-masked imines is critical allowed for higher yields and noticeably improved ee. The use of N-aluminoimines, which are not only easy to prepare by a partial reduction of nitriles, but are also relatively stable for both enolizable and non-enolizable substrates, considerably expanded the scope of the reactions. In this review, the developments in the syntheses of chiral homoallylic amines using organoboranes, with the particular accent on the reagent-controlled reactions, are summarized. Additionally, the novel methodology for the crotyl- and alkoxyallylboration of imines using trialkylboron "ate" complexes is described.
Pharmacologically active boranes
Authors: Jabbour Adel , Smoum Reem , Takrouri Khuloud , Shalom Eli , Zaks Batia , Steinberg Doron , Rubinstein Abraham , Goldberg Israel , Katzhendler Jehoshua , Srebnik Morris
Published: July 2006

Novel methods are described for the preparation of alkyldimethylamine cyanoboranes and β-hydroxylalkyldimethylamine cyanoboranes by C-lithiation of trimethylamine cyanoboranes followed by reaction with alkyl halides, aldehydes, and ketones. Lithiation of the monobromo derivatives of amine cyanoboranes led to the synthesis of the first examples of diborane derivatives of amine cyanoboranes. Bromo derivatives of amine cyanoboranes and amine carboxyboranes have been synthesized by new simple and efficient methods. Amine fluorocyanoboranes and amine fluorocarboxyboranes, new classes of compounds, have been prepared from the bromo precursors by fluorine/bromine exchange using fluorinating reagents such as AgF and Et3N.3HF. Eight different derivatives of oxazaborolidines were synthesized and evaluated for their affect on Streptococcus mutans viability, adhesion, and biofilm formation using 3[H]-thymidine labeled bacteria, and fluorescent stained bacteria. This is the first reported antibacterial activity of this class of compounds. The minimal inhibitory concentration (MIC) values ranged from 0.26 to 10 mM. Structure-activity relationship was observed. The B-butyl moiety of the oxazaborolidines contributed an anti-adhesion effect for all derivatives, while its effect diminished when the boron atom was incorporated in a fused heterocyclic ring. The B-phenyl group induced bacterial adhesion in all tested compounds. In a separate study for boronated saccahrides and enzymatic inhibition, the complex formation between N-butylboronic acid and a series of monosaccharides was investigated by 1H, 13C, and 11B NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS). Then, a series of boronic acid compounds with protease inhibition properties were prepared. The effect of added mono-, di-, and polysaccharides on the inhibitory activity of these compounds was studied. Potassium organotrifluoroborates were found to be reversible competitive inhibitors of α-chymotrypsin and trypsin. Based on 19F NMR, it was speculated that they inactivate the enzymes as a result of the formation of hydrogen bonds between fluorine atoms of the inhibitors and the serine protease.
Standards, calibration, and guidelines in microcalorimetry. Part 2. Calibration standards for differential scanning calorimetry* (IUPAC Technical Report)
Authors: Della Gatta Giuseppe , Richardson Michael J. , Sarge Stefan M. , Stølen Svein
Published: July 2006

Differential scanning calorimeters (DSCs) are widely used for temperature, heat capacity, and enthalpy measurements in the range from subambient to high temperatures. The present recommendations describe procedures and reference materials (RMs) for the calibration of DSCs. The recommendations focus on the calibration of the response of the instrument and on the estimation of the measurement uncertainty. The procedures for temperature, enthalpy, and heat-flow rate calibration are given in detail. Calibration on cooling has also been considered. Recommended RMs are listed, and the relevant properties of these materials are discussed.
β-Carotene and angiogenesis
Authors: Dembińska-Kieć Aldona , Malczewska-Malec Malgorzata , Polus Anna , Kieć-Wilk Beata , Grzybowska Joanna , Stachura Jerzy , Dyduch Grzegorz , Pryjma Julian , Skrzeczyńska Joanna , Langman Thomas , Bodzioch Marek , Partyka Łukasz , Schmitz Gerd
Published: July 2006

Carotenoids and retinoids modulate growth and differentiation of a variety of cell types and are fundamental regulators of development. Endothelial cells play an important role in angiogenesis, which is essential for organogenesis and tissue remodeling, but also inflammatory response or carcinogenesis. Binding to the retinoid (RARs) or rexinoid (RXRs) receptors, all-trans-RA, 13-cis-RA, 9-cis-RA, and synthetic retinoids and rexinoids showed antiangiogenic properties in several models. However, the role of β-carotene in endothelial cell function and angiogenesis is still poorly characterized. Although in our experiments, β-carotene used in nontoxic concentrations (up to 3 μM) had no detectable effect on the proliferation or apoptosis of HUVECs or umbilical-cord-blood-derived endothelial progenitors; β-carotene did not change the tubulogenic activity of cells in an in vitro angiogenesis model, but it potently activated the migration of endothelial and progenitor cells. β-Carotene also promoted the development of microcapillaries in a matrigel plug injected subcutaneously into mice. The analysis of microarray data from endothelial cells revealed that β-carotene modified the expression of genes involved in activation of chemotaxis, cell/cell and cell/matrix adhesion, matrix reorganization, G-protein-regulated intracellular signaling as well as genes involved in the rapid remodeling of the actin cytoskeleton. We conclude that physiological levels of β-carotene stimulate early steps of angiogenic activity of endothelial cells by activation of cellular migration as well as matrix reorganization and reduction of cell adhesion.
Distribution and metabolism of dietary carotenoids in humans as a criterion for development of nutritional supplements
Authors: Khachik Frederick
Published: July 2006

There are approximately 40-50 carotenoids in commonly consumed fruits and vegetables in a typical U.S. diet. These can be divided into carotenoid epoxides, mono- and dihydroxycarotenoids, hydrocarbon carotenoids, and carotenol acyl esters. However, among these, only a selected group of carotenoids are routinely found in human plasma, breast milk, major organs, and ocular tissues. In addition, several carotenoid metabolites have also been isolated and characterized from human plasma, tissues, and ocular tissues. The proposed metabolic transformation of carotenoids in humans will be discussed. Dietary carotenoids and their metabolites have been implicated in the prevention of cancer, cardiovascular disease, and age-related macular degeneration (AMD). An approach for the development of a nutritional supplement that is based on the distribution of carotenoids and their metabolites in humans will be discussed.
Reactive intermediates in aqueous ozone decomposition: A mechanistic approach
Authors: Fábián István
Published: July 2006

This paper provides a detailed account of recent developments in the mechanistic interpretation of aqueous ozone decomposition. Experimental complications with collecting reliable kinetic information for this system are illustrated via a few examples. Classical and comprehensive data treatment methods are compared, and an advanced kinetic model is presented on the basis of simultaneous evaluation of about 60 kinetic traces recorded at 260, 430, and 600 nm. These are the wavelengths of the absorbance maxima of O3, O3
-, and CO3
-, respectively. The model is used to explore specific features of the initiation sequence, the role of reactive intermediates, and the carbonate ion inhibition. It is also demonstrated how a complex kinetic model can be validated by studying the system under specific experimental conditions.
Screening of Drugs and Toxic Compounds with Liquid Chromatography-Linear Ion Trap Tandem Mass Spectrometry
Authors: Sauvage François-Ludovic , Saint-marcoux Franck , Duretz Bénédicte , Deporte Didier , Lachatre Gérard , Marquet Pierre
Published: July 2006

Background: In clinical and forensic toxicology, general unknown screening is used to detect and identify exogenous compounds. In this study, we aimed to develop a comprehensive general unknown screening method based on liquid chromatography coupled with a hybrid triple-quadrupole linear ion trap mass spectrometer.

Methods: After solid-phase extraction, separation was performed using gradient reversed-phase chromatography. The mass spectrometer was operated in the information-dependent acquisition mode, switching between a survey scan acquired in the Enhanced Mass Spectrometry mode with dynamic subtraction of background noise and a dependent scan obtained in the enhanced product ion scan mode. The complete cycle time was 1.36 s. A library of 1000 enhanced product ion–tandem mass spectrometry spectra in positive mode and 250 in negative mode, generated using 3 alternated collision tensions during each scan, was created by injecting pure solutions of drugs and toxic compounds.

Results: Comparison with HPLC-diode array detection and gas chromatography-mass spectrometry for the analysis of 36 clinical samples showed that linear ion trap tandem mass spectrometry could identify most of the compounds (94% of the total). Some compounds were detected only by 1 of the other 2 techniques. Specific clinical cases highlighted the advantages and limitations of the method.

Conclusion: A unique combination of new operating modes provided by hybrid triple-quadrupole linear ion trap mass spectrometers and new software features allowed development of a comprehensive and efficient method for the general unknown screening of drugs and toxic compounds in blood or urine.
In Situ Amplified Chemiluminescent Detection of DNA and Immunoassay of IgG Using Special-Shaped Gold Nanoparticles as Label
Authors: Wang Zhouping , Hu Jianqiang , Jin Yan , Yao Xin , Li Jinghong
Published: July 2006

Background: Au(III) catalyzed luminol chemiluminescence (CL) is classic in luminescence analysis. Recently, spherical gold nanoparticles (Au-NPs) were found displaying far stronger catalytic activity on luminol CL than that of Au(III). Some methods based on Au-NPs probes have been developed for DNA detection or immunoassay. However, more complicated labeling or stripping procedures are often inescapable in these protocols.

Methods: We synthesized specially shaped, irregular gold nanoparticles (IGNPs) and found their catalytic efficiency on luminol CL to be 100-fold greater than that of spherical Au-NPs. Using the IGNPs-functionalized DNA oligomers and the IGNPs-modified anti-IgG as in situ chemiluminescent probes, we established sandwich-type analytic methods for rapid, simple, selective, and sensitive sequence-specific DNA detection and for human plasma IgG immunoassay, respectively. We used 12 clinical human plasma samples to examine the precision and accuracy of the proposed method for IgG content determination.

Results: Calibration curves for the oligonucleotide [ΔI = 15.73 + 27.55 (DNA) × 1010 (mol/L); R2 = 0.9936] and IgG [ΔI = 48.84 + 30.23 (IgG) × 1010 (mol/L); R2 = 0.9964] show good correlation, demonstrating the linear response over the concentrations tested (0.04–10 nmol/L for DNA, 0.05–10 nmol/L for IgG). The limit of detection, calculated based on 50 μL of a solution of calibrators, was 13 pmol/L for DNA and 17 pmol/L for IgG, with a signal-to-noise ratio of 3. We obtained good intra-and interassay reproducibility. The IgG contents in 12 human plasma samples obtained by the proposed method are identical with the data of clinical laboratory.

Conclusions: We developed a simple and sensitive method for in situ amplified chemiluminescence detection of sequence-specific DNA and immunoassay of IgG by use of highly active, specially shaped, irregular gold nanoparticles (IGNPs) as label and confirmed by clinical samples test. This method has many desirable features including rapid detection, selectivity, and little required instrumentation. This new protocol may be quite promising, with potentially broad applications for clinical immunoassays and DNA hybridization analysis.
Between a Rock and a Hard Place: Disclosing Medical Errors
Authors: Crone Kimberley G , Muraski Michele B , Skeel Joy D , Love-Gregory Latisha , Ladenson Jack H , Gronowski Ann M
Published: July 2006

Background: Healthcare-related errors cause patient morbidity and mortality. Despite fear of reprimand, laboratory personnel have a professional obligation to rapidly report major medical errors when they are identified. Well-defined protocols regarding how and when to disclose a suspected error by a colleague do not exist.

Patient: We describe a woman with a well documented allergy to sulfamethoxazole who was treated with sulfadiazine that led to toxic epidermal necrolysis. After the patient’s death, the laboratory medicine resident was asked by one of the patient’s physicians to measure serum sulfadiazine, but only if the results were not reported in the patient’s electronic medical record. The case was brought to the attention of a laboratory medicine faculty member and the hospital risk management team.

Issues: Laboratorians are patient fiduciaries and are responsible for reporting errors. Most medical associations have codes of ethics that address disclosure of incompetence and errors, although the AACC’s Guide to Ethics does not. New types of error, risk management, and root-cause analyses help to shift the focus to system errors and away from individuals’ errors. This can lead to a healthcare environment that encourages truth and disclosure rather than fear and reprimand.

Disposition: The individuals involved in the presented case fulfilled their fiduciary duty to the patient by reporting this incident. An extensive investigation showed that, in fact, no medical errors or misconducts had occurred in the care of the patient.
Strategic communication and institutional links in technology research and development
Authors: Crewe Emma , Sarkar Ashoke K
Published: July 2006

The centrality of knowledge to strategies for poverty reduction is widely assumed, but gaps between its generation and use persist. In this article what is known about redressing these gaps, particularly between researchers and policy-makers, are drawn together with an emphasis on understanding
the context, developing institutional links and engaging in effective communication. Three case studies about the positive and negative use of communication within the field of technology development are then considered. These cases research into agriculture in Ghana by two European universities,
a publicprivatecivil society coalition on agro-processing in India, and researchers advising a government road-building scheme in India highlight not only the central importance of communication to scaling up the impact of research but also that very different strategies are required for different
situations.
Automation in Chemical Industry (Automatisierung in der Chemischen Industrie)
Authors: Schuler Hans
Published: July 2006

Automation technology is an integral part of chemical plants since the beginning of industrial chemistry. The evolution of process automation has been driven by the specific requirements of process industry and by the innovation cycles of instrumentation technology and control theory. Chemical production plants are still a fruitful and inspiring application field of automation with an enormous leverage on production economy. Automation today is an enabling technology for production efficiency and operational excellence of chemical processes. This contribution outlines the development and new applications of automation and control in the field of process industry, and gives some ideas to facilitate the convergence of theoretical development and engineering practice.
Flatness-Based Tracking Control for Parabolic Distributed-Parameter Systems with Boundary Input (Flachheitsbasierte Folgeregelung für parabolische verteilt-parametrische Systeme mit Randeingriff)
Authors: Meurer Thomas , Zeitz Michael
Published: July 2006

The contribution considers the tracking control problem for nonlinear parabolic distributed-parameter systems with boundary input. It is shown that the combination of so-called formal power series and suitable summation methods provides an integrated approach to the flatness-based feedforward and feedback tracking control design with observer. The performance of the proposed control scheme is evaluated by considering various diffusion-convection-reaction models for tubular or fixed-bed reactors.
Diagnosis of Discretely Controlled Continuous Systems (Diagnose ereignisgesteuerter Systeme)
Authors: Lunze Jan
Published: July 2006

The papers presents five diagnostic methods for discretely controlled continuous systems, which differ with respect to the model and measurement information used. From the hybrid model, four more abstract representations are derived, which have the form of embedded maps, semi-Markov processes, timed automata or nondeterministic automata. The validity of the diagnostic result is ensured by the claim that the models should be complete and, hence, consistent with all the input-output sequences of the discretely controlled system in the appropriate fault case. In this way a hierarchy of models and of diagnostic results is obtained.
Effects of Stenting on Blood Flow in a Coronary Artery Network Model
Authors: Raghu R. , Pullan A. , Smith N.
Published: July 2006

The effect of stenting on blood flow is investigated using a model of the coronary artery network. The parameters in a generic non‐linear pressure–radius relationship are varied in the stented region to model the increase in stiffness of the vessel due to the presence of the stent. A computationally efficient form of the Navier–Stokes equation is solved using a Lax–Wendroff finite difference method. Pressure, vessel radius and flow velocity are computed along the vessel segments. Results show negative pressure gradients at the ends of the stent and increased velocity through the middle of the stented region. Changes in local flow patterns and vessel wall stresses due to the presence of the stent have been shown to be important in restenosis of vessels. Local and global pressure gradients affect local flow patterns and vessel wall stresses, and therefore may be an important factor associated with restenosis. The model presented in this study can be easily extended to solve flows for stented vessels in a full, anatomically realistic coronary network. The framework to allow for the effects of the deformation of the myocardium on the coronary network is also in place.
ALS gene proline (197) mutations confer ALS herbicide resistance in eight separated wild radish (Raphanus raphanistrum) populations
Authors: Yu Qin , Zhang Xiao Qi , Hashem Abul , Walsh Michael J. , Powles Stephen B.
Published: July 2006

The biochemical and molecular basis of resistance to acetolactate synthase (ALS)–inhibiting herbicides was investigated in eight resistant (R) and three susceptible (S) wild radish populations. In vitro enzyme assays revealed an ALS herbicide–resistant ALS enzyme in all R populations. ALS enzyme extracted from the shoots of all eight R populations was highly resistant to the ALS-inhibiting sulfonylurea herbicide chlorsulfuron (20- to 160-fold) and the triazolopyrimidine herbicide metosulam (10- to 46-fold) and moderately resistant to metsulfuron (three to eightfold). There was little or no cross-resistance to the imidazolinone herbicides imazapyr and imazethapyr. The ALS gene fragment covering potential mutation sites in these populations was amplified, sequenced, and compared. All eight R populations had point mutations in the codon for the proline residue in Domain A. However, the point mutations varied and encoded four different amino acid substitutions: histidine, threonine, alanine, and serine. No nucleotide difference in the DNA sequence of Domains C and D resulting in amino acid substitutions was observed between the R and S populations examined. In addition, a three- to fivefold higher ALS-specific activity was consistently observed in all R populations compared with S populations, whereas Northern blot analysis detected a similar level of ALS mRNA, suggesting a possible translational–posttranslational regulation of the enzyme. It is concluded that selection pressure from chlorsulfuron on eight separate wild radish populations has resulted in target site mutation at the same proline residue in the ALS gene. Higher ALS activity also may play a role in the resistance level.
Cool-Season Turfgrass Reseeding Intervals for Bispyribac-Sodium
Authors: Lycan Darren W. , Hart Stephen E.
Published: July 2006

Field studies were conducted in 2002 and 2003 in New Jersey to determine the length of time after a bispyribac-sodium application at which creeping bentgrass, Kentucky bluegrass, and perennial ryegrass can be safely reseeded. Bispyribac at 148 or 296 g ai/ha was applied 6, 4, 2, or 1 week before seeding (WBS). Bispyribac at 148 g/ha applied 1 WBS reduced ground cover of creeping bentgrass and Kentucky bluegrass at 3 weeks after seeding (WAS) by 30 and 42% as compared to the nontreated check, respectively. Reductions in Kentucky bluegrass and creeping bentgrass ground cover from bispyribac at 296 g/ha applied 1 WBS were evident at 28 WAS, whereas perennial ryegrass recovered from initial reductions in ground cover by this time. Applications made 6 to 2 weeks before seeding did not adversely affect ground cover of any species at any evaluation date as compared to the nontreated check. These studies suggest creeping bentgrass, Kentucky bluegrass, and perennial ryegrass can be safely reseeded 2 weeks after a bispyribac application. However, ground cover may be reduced by bispyribac applied 1 WBS.
Common lambsquarters (Chenopodium album) interference with corn across the northcentral United States
Authors: Fischer David W. , Harvey R. Gordon , Bauman Thomas T. , Phillips Sam , Hart Stephen E. , Johnson Gregg A. , Kells James J. , Westra Philip , Lindquist John
Published: July 2006

Variation in crop–weed interference relationships has been shown for a number of crop–weed mixtures and may have an important influence on weed management decision-making. Field experiments were conducted at seven locations over 2 yr to evaluate variation in common lambsquarters interference in field corn and whether a single set of model parameters could be used to estimate corn grain yield loss throughout the northcentral United States. Two coefficients (IandA) of a rectangular hyperbola were estimated for each data set using nonlinear regression analysis. TheIcoefficient represents corn yield loss as weed density approaches zero, andArepresents maximum percent yield loss. Estimates of both coefficients varied between years at Wisconsin, andIvaried between years at Michigan. When locations with similar sample variances were combined, estimates of bothIandAvaried. Common lambsquarters interference caused the greatest corn yield reduction in Michigan (100%) and had the least effect in Minnesota, Nebraska, and Indiana (0% yield loss). Variation inIandAparameters resulted in variation in estimates of a single-year economic threshold (0.32 to 4.17 plants m−1of row). Results of this study fail to support the use of a common yield loss–weed density function for all locations.