bluuebunny/crossref_metadata_2025 huggingface dataset:
N
-Ethyl-
N
-Nitrosourea Mutagenesis: Boarding the Mouse Mutant Express
Authors: Cordes Sabine P.
Published: September 2005

In the mouse, random mutagenesis with
N
-ethyl-
N
-nitrosourea (ENU) has been used since the 1970s in forward mutagenesis screens. However, only in the last decade has ENU mutagenesis been harnessed to generate a myriad of new mouse mutations in large-scale genetic screens and focused, smaller efforts. The development of additional genetic tools, such as balancer chromosomes, refinements in genetic mapping strategies, and evolution of specialized assays, has allowed these screens to achieve new levels of sophistication. The impressive productivity of these screens has led to a deluge of mouse mutants that wait to be harnessed. Here the basic large- and small-scale strategies are described, as are the basics of screen design. Finally, and importantly, this review describes the mechanisms by which such mutants may be accessed now and in the future. Thus, this review should serve both as an overview of the power of forward mutagenesis in the mouse and as a resource for those interested in developing their own screens, adding onto existing efforts, or obtaining specific mouse mutants that have already been generated.
Activation of chlorobenzene with Ni(0)N,N-chelates  A remarkably profound effect of a minuscule change in ligand structure
Authors: Marshall William J , Grushin Vladimir V
Published: September 2005

Activation of the CCl bond of chlorbenzene with [(COD)2Ni] and a bidentate N,N-ligand such as N,N,N′,N′-tetramethylethylenediamine (tmeda) and 2,2′-bipyridyl (bipy) has been reported to produce σ-phenyl complexes [(tmeda)Ni(Ph)Cl] (1) and [(bipy)Ni(Ph)Cl], respectively. However, in sharp contrast, we found that similar reactions involving almost the identical ligands N,N,N′,N′-tetraethylethylenediamine (teeda) and 6,6′-dimethyl-2,2′-bipyridyl (6,6′-Me2bipy) resulted in homocoupling and the formation of non-organometallic dichlorocomplexes [(teeda)NiCl2] and [(6,6′-Me2bipy)NiCl2]. The latter two compounds and 1 were characterized by single-crystal X-ray diffraction data. The remarkable change in the reaction outcome points to its extremely high sensitivity to minor alterations in the structure of the stabilizing N,N-ligand. In contrast, analogous reactions of [Pd(dba)2] with PhI in the presence of teeda or 1,2-dipiperidinoethane (dpe) produced the expected σ-phenyl complexes [(teeda)Pd(Ph)I] and [(dpe)Pd(Ph)I], much like the previously reported reaction with tmeda.Key words: C-Cl activation, zerovalent nickel complexes, N,N-ligands, oxidative addition, homocoupling, X-ray analysis.
Coordination polymers with Co(II) sulfate layers linked by alkanediamines of varying chain length
Authors: Behera J N , Rao C NR
Published: September 2005

Coordination polymers of the general formula Co[HN(CH2)nNH]SO4 possessing layers formed by CoO4N2 octahedra and SO4 tetrahedra have been synthesized under solvothermal conditions. The layers, linked by diaminoalkanes, cause apertures of varying widths, which are determined by the chain length of the amine. These materials appear to possess weak ferromagnetic interaction at low temperatures.Key words: coordination polymers, cobalt sulfate, solvothermal synthesis.
Oxidative addition chemistry of dimethyl(dipyridyl ketone)platinum(II)
Authors: Zhang Fenbao , Broczkowski Michael E , Jennings Michael C , Puddephatt Richard J
Published: September 2005

The dimethylplatinum(II) complex [PtMe2(DPK)] (DPK = di-2-pyridyl ketone) undergoes easy oxidative addition to give platinum(IV) complexes. For example, reaction of [PtMe2(DPK)] with MeI gave [PtIMe3(DPK)], reaction with N-chlorosuccinimide in methanol gave [PtCl(OMe)Me2(DPK)], and reaction with [FN(CH2CH2)2NCH2Cl][BF4]2 in MeCN gave [PtF(NCMe)Me2(DPK)][BF4]. In several cases, the ketone group of the DPK ligand took part in the reactions. For example, oxidation of [PtMe2(DPK)] by air or hydrogen peroxide gave [Pt(OH)Me2(DPKOH)] (DPKOH = κ3-NN′O-(2-C5H4N)2C(OH)O), which reacted with HCl to give [PtClMe2(DPKOH)] or with excess acetyl chloride to give [PtCl2Me2(DPK)]. Reaction of [PtMe2(DPK)] with methyl triflate in MeCN solution gave [PtMe3(NCMe)(DPK)][OTf], which reacted with more MeOTf in the presence of base to give [PtMe3{DPC(OMe)2}][OTf], where DPC(OMe)2 = κ3-NN′O-(2-C5H4N)2C(OMe)2. Hydrolysis of [PtF(NCMe)Me2(DPK)][BF4] gave [Pt{NHC(=O)Me}Me2(DPKOH)], which crystallized in partially protonated form as an unusual supramolecular polymer [Pt{NHC(=O)Me}Me2(DPKOH)]·0.5HBF4.Key words: platinum, oxidative addition, ketone, pyridyl.
Synthesis and application of L-N-Boc-N-methyl-β-hydroxyvaline in the preparation of a depsipeptide
Authors: Dettwiler James E , Bélec Laurent , Lubell William D
Published: September 2005

Enantiopure (>99% ee) L-N-tert-butyloxycarbonyl-N-methyl-β-hydroxyvaline (2) was synthesized in six steps and 43% overall yield from D-serine methyl ester (5). Methyl (4S)-N-(9-phenylfluoren-9-yl)-oxazolidine-4-carboxylate (7) was prepared in two steps and 73% yield by N-phenylfluorenation of 5 followed by cyclization of N-(PhF)amino alcohol 6 with formaldehyde and catalytic p-toluenesulfonic acid (PhF = 9-phenylfluoren-9-yl). The addition of MeLi to oxazolidine carboxylate 7 produced the tertiary alcohol 8 in 91% yield. Oxazolidines 8 equilibrated with oxazolidine 9 under acidic conditions. Reduction of pure 8 or the mixture of oxazolidines 8 and 9 with NaCNBH3 and hydrochloric acid in anhydrous dioxane afforded N-methyl amino diol 11 in 86%92% yields. Attempts to selectively oxidize N-(PhF)amino diol 11 were unsuccessful; however, hydrogenation of 11 in the presence of di-tert-butyl dicarbonate gave the corresponding N-(Boc)amino diol 12 in 82% yield. Selective oxidation of diol 12 was performed using a cocktail containing TEMPO free radical, NaClO2, and NaOCl to give L-N-Boc-N-methyl-β-hydroxyvaline (2) in 87% yield. Coupling of β-hydroxyvaline 2 and (S)-2-hydroxy-3-methylbutanoate (15) was accomplished by using the methodology of Mitsunobu to provide depsipeptide Boc-(S)-HOMeVal-(R)-Hmb (4) for use as a building block in the synthesis of the cyclic antifungal depsipeptide aureobasidin B.Key words: N-methylated amino acid, serine, depsipeptide, aureobasidin.
Pd(0)PhCOOH catalyzed addition of oxygen pronucleophiles to allenes and internal alkynes
Authors: Patil Nitin T , Pahadi Nirmal K , Yamamoto Yoshinori
Published: September 2005

We have developed a catalytic system that enables the addition of alcohols to allenes using a combination of 5 mol% Pd(PPh3)4 and 10 mol% benzoic acid. Likewise, the addition reaction of carboxylic acids to alkynes is described. In all cases the reaction proceeded well, giving the corresponding allylation products in good-to-high yields with high regio- and stereoselectivities.Key words: addition, alcohols, carboxylic acids, allenes, alkynes, palladium.
Oxidation of anisoles to p-benzoquinone monoketals catalyzed by a ruthenium complex of 1,4,7-trimethyl-1,4,7-triazacyclononane with tert-butyl hydroperoxide
Authors: Cheung Wai-Hung , Yip Wing-Ping , Yu Wing-Yiu , Che Chi-Ming
Published: September 2005

A protocol based on [RuIII(Me3tacn)(CF3CO2)2(H2O)]CF3CO2 (1, Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane) as catalyst and tert-butyl hydroperoxide (TBHP) as oxidant was developed for oxidation of anisoles to p-benzoquinone monoketals. This reaction can be formally considered as regioselective aromatic C-H oxidation. With 2-methoxyanisole as substrate, 3,4-dimethoxy-4-tert-butoxy-2,5-cyclohexadienone can be obtained in up to 82% yield based on 84% substrate conversion.Key words: oxidation, quinones, tert-butyl hydroperoxide, ruthenium catalyst.
An alternative convergent synthesis of silole-core dendrimers
Authors: Sanji Takanobu , Ishiwata Hiroyuki , Kaizuka Tomoyoshi , Tanaka Masato , Sakurai Hideki , Nagahata Ritsuko , Takeuchi Kazuhiko
Published: September 2005

Silole-core dendrimers having benzyl-ether-type dendron units in the periphery are readily synthesized by the Ni-catalyzed reaction of benzyloxy-substituted diphenylacetylenes with 1,1,2,2-tetramethyldisilane.Key words: silole, dendrimer, nickel-catalyzed reaction, convergent synthesis.
A practical guide to arylbiguanides  Synthesis and structural characterization
Authors: LeBel Olivier , Maris Thierry , Duval Hugues , Wuest James D
Published: September 2005

Monohydrochloride salts of diverse 1-arylbiguanides and 1,5-diarylbiguanides were synthesized by the reaction of anilinium chlorides with dicyandiamide or sodium dicyanamide, and the biguanidinium chlorides were converted into the corresponding biguanides by deprotonation with methanolic NaOCH3. The resulting biguanides and their salts were fully characterized by spectroscopic methods, and the structures of representative compounds were determined by X-ray crystallography.Key words: biguanide, biguanidinium, synthesis, structure, hydrogen bonds, noncovalent interactions, supramolecular chemistry.
Ruthenium catalyzed asymmetric hydrogenation of α- and β-keto esters in ionic liquids using chiral P-Phos ligand
Authors: Lam Kim Hung , Xu Lijin , Feng Lichun , Ruan Jiwu , Fan Qinghua , Chan Albert SC
Published: September 2005

Chiral dipyridylphosphine ligand P-Phos was used in the Ru catalyzed asymmetric hydrogenation of α- and β-keto esters in room temperature ionic liquids (RTILs) with high conversions and good to excellent enantioselectivities. The catalyst was recycled by simple extraction and reused five times without loss of activity and enantioselectivity.Key words: ruthenium, asymmetric hydrogenation, keto ester, ionic liquids, P-Phos.
Efficient ruthenium catalyzed transfer hydrogenation of functionalized imines by isopropanol under controlled microwave heating
Authors: Samec Joseph S.M , Mony Laetitia , Bäckvall Jan-E.
Published: September 2005

Transfer hydrogenation of various functionalized imines by isopropanol catalyzed by [Ru(CO)2(Ph4C4CO)]2 (3) has been studied. The use of either an oil bath or controlled microwave heating in toluene led to an efficient procedure with high turnover frequencies and the product amines were obtained in high yields. An advantage with catalyst 3 over the conventional [Ru2(CO)4(µ-H)(Ph4C4COHOCC4Ph4)] (1) is the absence of an initiation period, which results in a faster reaction with 3 as compared to 1.Key words: transfer hydrogenation, ruthenium, imines, microwave.
Surface organometallic chemistry  Carbonyl complexes of Re(I) with silanolates as models of silica anchored rhenium carbonyl species
Authors: D'Alfonso Giuseppe , Dragonetti Claudia , Galli Simona , Lucenti Elena , Macchi Piero , Roberto Dominique , Ugo Renato
Published: September 2005

Reaction of Me3SiONa with [Re(CO)5Cl] affords the new complex Na[Re2(CO)6(µ-OSiMe3)3], which could be generated via formation of [Re(CO)5OSiMe3] followed by immediate reaction with Me3SiO. Substitution of some CO ligands by phosphines significantly decreases the electrophilicity of the Re(I) center, and therefore hinders further attack by Me3SiO. Thus, fac-[Re(CO)3(Ph2PCH2CH2PPh2)OTf] (OTf is the triflate anion) reacts with Me3SiONa to give fac-[Re(CO)3(Ph2PCH2CH2PPh2)OSiMe3], a molecular model of silica anchored [Re(CO)5OSi≡]. However, substitution of only one CO by triphenylphosphine is not enough to avoid the formation of [Re2(CO)6(µ-OSiMe3)3]. While fac-[Re(CO)3(Ph2PCH2CH2PPh2)OSiMe3] is stable towards hydrolysis, [Re2(CO)6(µ-OSiMe3)3]is readily hydrolyzed to [Re2(CO)6(µ-OH)(µ-OSiMe3)2], a molecular model of silica anchored [Re2(CO)6(µ-OH)(µ-OSi≡)2], whose structure has been determined by single crystal X-ray diffraction. Key words: surface organometallic chemistry, rhenium, silica, silanolate, molecular model.
Alkylcobalt carbonyls. Part XIV. Generation of chiral conformations by centers of chirality in organocobalt complexes
Authors: Zucchi Claudia , Turrini Davide , Boese Roland , Bencze Lajos , Kurdi Robert , Caglioti Luciano , Pályi Gyula
Published: September 2005

R1OC(O)CH2Co(CO)3PR23 complexes (3), (R1 = S-EtOC(O)CH(CH3), R2 = Ph, a; R1 = (1S,2R,5S)-2-isopropyl-5-methylcyclohexyl, R2 = Ph, b; R1 = (1R,2S,5R)-2-isopropyl-5-methylcyclohexyl, R2 = Ph, c; R1 = isopropyl, R23 = Ph2{(1S,2S,5R)-2-isopropyl-5-methylcyclohexyl}, d) were prepared and characterized by analyses including IR, 1H-, 13C{1H}-, and 31P{1H} NMR spectra as well as by X-ray diffraction structure determination. Principles of self-organization of chiral conformations were deduced from the structural data.Key words: alkylcobalt carbonyls, cooperative phenomena, intramolecular, chirality, conformations.
PausonKhand reactions in water
Authors: Krafft Marie E , Wright James A , Boñaga Llorente VR
Published: September 2005

We have investigated the cobalt mediated PausonKhand (PK) reaction in water. In the presence of detergents and surfactants, Co2(CO)8 and Co4(CO)12 are effective under aqueous-phase, thermal PK reactions. In a waterTriton®X-100 medium, Co4(CO)12 is catalytically active. Further, dicobalthexacarbonyl complexes of alkynes and enynes undergo effective cyclization under thermal (70 °C) and NMO-promoted conditions. The oxidative nature of the latter conditions inhibits the reductive PK reaction. In all protocols, moderate to excellent yields of the cycloadducts are obtained. Substrates that are prone to hydrolysis, such as acetals, highly activated carboxylic acid derivatives, and those bearing propargylic heteroatom groups are tolerated under appropriate conditions. Finally, the more challenging intermolecular cycloadditions can also be easily achieved under aqueous conditions.Key words: alkyne, cycloaddition, green chemistry, PausonKhand reaction, water.
Effects of Chai Hu (Radix Burpleuri) Containing Formulation on Plasma β-endorphin, Epinephrine and Dopamine in Patients
Authors: Chen Jia-Xu , Ji Bo , Lu Zhao-Lin , Hu Li-Sheng
Published: September 2005

Chai Hu (Radix Burpleuri), a major ingredient in many traditional Chinese medicine formulas, such as Xiao Yao Wan, is used in the treatment of liver stagnation and spleen deficiency syndrome (LSSDS). The objectives of this study were to examine the effects of Xiao Yao Wan containing Chai Hu on the changes of plasma indices in patients with LSSDS. Fifty-eight cases of LSSDS were randomly divided into two groups: 41 cases in the experimental group were treated with Xiao Yao Wan containing Chai Hu and 17 cases in the control group were treated with Zhi Bai Di Huang Wan for one consecutive month in a single blind design. Before and after treatment, high performance liquid chromatography (HPLC) was applied to determine the changes of plasma norepinephrine (NE), epinephrine (E) and dopamine (DA). Radioimmunoassay was performed to measure the amount of plasma β-endorphin (β-EP), adrenocorticotropin hormone (ACTH), estradiol (E2) and testosterone (T), and laser nephelometry was also conducted to measure plasma immunoglobulin A (Ig A) and G (Ig G). Compared to baseline levels, plasma β-EP was significantly increased ( p < 0.01), while E and DA were markedly decreased ( p < 0.01) after the administration of Xiao Yao Wan in the experimental group. The other indices did not change. This is the first evidence showing that the effect of Xiao Yao Wan containing Chai Hu on the treatment of patients with LSSDS may be through enhancing plasma β-EP and decreasing E and DA release. We conclude that Xiao Yao Wan containing Chai Hu regulates nervous and endocrine systems and contributes to the improvement of the clinical status of patients with LSSDS.
Traditional Chinese Herbs Against Hypertension Enhance the Effect of Memory Acquisition
Authors: Ho Shih-Ching , Ho Yueh-Feng , Lai Tzung-Hsien , Liu Tsu-Hwie , Wu Rey-Yih
Published: September 2005

Recent findings of a link between high blood pressure (BP) and dementia have given new prospects. The aim of this study is to analyze a mixture of Chinese herbs, Tianma Gouteng Decoction (TGD), which was traditionally used to treat hypertension, and investigate its relation to ameliorating cognitive impairment. We discovered that TGD also had properties involving enhancement of memory acquisition (learning) skills in mice, but not memory consolidation. It was observed that TGD could prolong the step-through latency at doses of 1.0 and 2.5 g/kg on passive avoidance task in mice. TGD could be developed further to treat mice with amnesia, which was induced by scopolamine at the same dose under long-term (8 days) administration.
Antioxidant and Antiplatelet Effects of Dang-Gui-Shao-Yao-San on Human Blood Cells
Authors: Shen Ai-Yu , Wang Trey-Shy , Huang Mei-Han , Liao Chang-Hui , Chen Sheue-Jiun , Lin Chun-Ching
Published: September 2005

Dang-Gui-Shao-Yao-San (DGSYS) is a mixture of medicinal herbs, which has long been used in traditional Chinese medicine for treating anemia and ovulary disorders. Its preparation comprises Angelicae sinensis (Oliv.) Diels, Ligustucum chuanxiong Hort, Paeonia lactiflora pall, Poria cocos (Schw.) Wolf, Atractylodis macrocephala Koidz and Alisma orientalis (Sam.) Juzep. The present study examined the anti-superoxide formation, free radical scavenging and anti-lipid peroxidation activities of DGSYS by xanthine oxidase inhibition, cytochrome C system with superoxide anion released by the fMLP or PMA activating pathway in human neutrophils, and FeCl2ascorbic acid-induced lipid peroxidation effects on lipids in rat liver homogenate, respectively. DGSYS showed anti-superoxide formation and free radical scavenging activity in a concentration-dependent manner. It also inhibited PMA- but not fMLP-induced superoxide anion released from human neutrophils. These antioxidant actions of DGSYS showed beneficial cytoprotective effects against lipid peroxidation in rat liver homogenate, human platelet aggregation induced by arachidonic acid (AA) and adenosine diphosphate (ADP) and mitomycin C-mediated hemolytic in human erythrocytes.
Activity of Wen-Pi-Tang, and Purified Constituents of Rhei Rhizoma and Glycyrrhizae Radix against Glucose-Mediated Protein Damage
Authors: Nakagawa Takako , Yokozawa Takako , Kim Young Ae , Kang Ki Sung , Tanaka Takashi
Published: September 2005

Wen-Pi-Tang, an Oriental medical prescription composed of Rhei Rhizoma, Ginseng Radix, Aconiti Tuber, Zingiberis Rhizoma and Glycyrrhizae Radix, is used clinically as a medicine to treat renal failure. This study was conducted to examine the inhibitory activity of the five crude drug components of Wen-Pi-Tang and several pure compounds isolated from Rhei Rhizoma and Glycyrrhizae Radix against the protein glycation reaction. Rhei Rhizoma exerted the most potent activity, Zingiberis Rhizoma and Glycyrrhizae Radix showed relatively moderate activity, whereas Aconiti Tuber and Ginseng Radix showed weak activity. On the other hand, of 20 compounds obtained from Rhei Rhizoma and Glycyrrhizae Radix, tannins, especially rhatannin, RG-tannin and procyanidin B-2 3,3′-di-O-gallate, showed significantly strong activities that were more effective than the positive control, aminoguanidine. Some flavones such as licochalcone A and licochalcone B, and anthraquinones such as emodin and aloe-emodin, also showed inhibitory activity. These findings may help to explain, at least in part, certain pharmacological activities of Wen-Pi-Tang, whose clinical efficacy against renal failure is already recognized.
Isolation and Structure Elucidation of a New Potent Anti-neoplastic Diterpene from Dendrostellera lessertii
Authors: Sadeghi H. , Yazdanparast R.
Published: September 2005

Two diterpene esters were isolated from Dendrostellera lessertii. These compounds were identified as compound I (12-O-benzoyl-3,5-hydroxy-6,7-epoxy-resiniferonol-9,13,14-orthobenzoate) and compound II (12-O-benzoyl-5-hydroxy-6,7-epoxy-resiniferonol-9,13,14-orthodecanoate). Cytotoxicity evaluation of these two compounds, using seven different cancerous cell lines, indicated that compound I with IC50 of 5–25 nmol, is 2.5 times more active than compound II. Using flow cytometry technique, it was found that treatment of the most responsive cells (K562) with compound I inhibited the progression of cells through G1 phase by almost 20% compared to the untreated cells.
The Revival of a Tradition of Chinese Medicine in a Reclaimed Chinese Territory
Authors: Wong Jenny , Woo Jean
Published: September 2005

The effect of the political transition from a British Colony to a Special Administration Region of China in 1997 on the tradition of Chinese medicine is examined using historical reviews as well as interviews with various sectors of the population in Hong Kong. Results show that the political change has stimulated the formation of a location-specific Hong Kong Chinese medicine strongly characterized by both scientific and commercial elements developed from the culture of Chinese medicine.
Effects of Ganoderma lucidum Extract on Chemotherapy-Induced Nausea and Vomiting in a Rat Model
Authors: Wang Chong-Zhi , Basila Daniel , Aung Han H. , Mehendale Sangeeta R. , Chang Wei-Tien , McEntee Eryn , Guan Xiongfei , Yuan Chun-Su
Published: September 2005

Chemotherapy is highly cytotoxic, causing a number of severe adverse effects such as nausea and vomiting. Herbal medicines, which can often be used on a daily basis for prolonged treatment, may be clinically beneficial. Ganoderma lucidum or Lingzhi mushroom has been recognized as a remedy in treating a number of medical conditions, including balancing immunity and decreasing drug-induced side effects. It has been shown that rats react to emetic stimuli, like the chemotherapy agent cisplatin, by increased consumption of kaolin, known as pica; and this rat model has been utilized to evaluate novel anti-emetic compounds. In this study, we evaluated the effects of a G. lucidum extract (SunRecome®, the most commonly used Lingzhi mushroom extract in China) in attenuating cisplatin-induced nausea and vomiting in the rat pica model. We observed that intraperitoneal cisplatin injection caused a significant increase in kaolin intake at 24, 48, 72 and 96 hours, reflecting cisplatin's nausea and vomiting action. This cisplatin-induced kaolin intake dose-dependently decreased after 1, 3 and 10 mg/kg G. lucidum extract injection ( p < 0.01). In addition, there was a significant reduction of food intake after cisplatin. The cisplatin-induced food intake reduction improved significantly after G. lucidum extract administrations in a dose-related manner ( p < 0.01), suggesting a supportive effect of the extract on general body condition. Future controlled clinical trials are needed to evaluate the safety and effectiveness of this herbal medication.
EFFECTS OF THE MAGNETIC FLUX AND OF THE ELECTRON MOMENTUM ON THE TRANSMISSION AMPLITUDE IN THE AHARONOV–BOHM INTERFEROMETER
Authors: AMARESH KUMAR M. V. , SAHOO DEBENDRANATH
Published: September 2005

A characterization of the two-terminal open-ring Aharonov–Bohm interferometer is made by analyzing the phase space plots in the complex transmission amplitude plane. Two types of plots are considered: type 1 plot uses the magnetic flux as the variable parameter and type 2 plot which uses the electron momentum as the variable parameter. In type 1 plot, the trajectory closes upon itself only when the ratio R of the arm lengths (of the interferometer) is a rational fraction, and the shape and the type of the generated flower-like pattern is sensitive to the electron momentum. For momenta corresponding to discrete eigenstates of the perfect ring (i.e., the ring without the leads), the trajectory passes through the origin a certain fixed number of times before closing upon itself, whereas for arbitrary momenta it never passes through the origin. Although the transmission coefficient is periodic in the flux with the elementary flux quantum as the basic period, the phenomenon of electron transmission is shown not to be so when analyzed via the present technique. The periodicity is seen to spread over several flux units whenever R is a rational fraction whereas there is absolutely no periodicity present when R is an irrational number. In type 2 plot, closed trajectories passing through the origin a number of times are seen for R being a rational fraction. The case R = 1 (i.e., a symmetric ring) with zero flux is rather pathological — it presents a closed loop surrounding the origin. For irrational R values, the trajectories never close.
DYNAMICS OF BRIGHT MATTER WAVE SOLITONS IN A BOSE–EINSTEIN CONDENSATE
Authors: Kh. ABDULLAEV FATKHULLA , GAMMAL ARNALDO , KAMCHATNOV ANATOLY M. , TOMIO LAURO
Published: September 2005

Recent experimental and theoretical advances in the creation and description of bright matter wave solitons are reviewed. Several aspects are taken into account, including the physics of soliton train formation as the nonlinear Fresnel diffraction, soliton-soliton interactions, and propagation in the presence of inhomogeneities. The generation of stable bright solitons by means of Feshbach resonance techniques is also discussed.
CONSTRUCTING ALGEBRAIC LINKS FOR LOW EDGE NUMBERS
Authors: McCABE CYNTHIA L.
Published: September 2005

A method is given for economically constructing any algebraic knot or link K. This construction, which involves tree diagrams, gives a new upper bound for the edge number of K that is proven to be at most twice the crossing number of K. Furthermore, it realizes a minimal-crossing projection.
FRAMED KNOTS IN 3-MANIFOLDS AND AFFINE SELF-LINKING NUMBERS
Authors: CHERNOV TCHERNOV VLADIMIR
Published: September 2005

The number |K| of non-isotopic framed knots that correspond to a given unframed knot K ⊂ S3 is infinite. This follows from the existence of the self-linking number slk of a zero homologous framed knot. We use the approach of Vassiliev–Goussarov invariants to construct "affine self-linking numbers" that are extensions of slk to the case of nonzero homologous framed knots in 3-manifolds.

As a corollary we get that |K| = ∞ for all knots in an oriented (not necessarily compact) 3-manifold M that is not realizable as a connected sum (S1 × S2)# M′. This result for compact manifolds was first stated by Hoste and Przytycki. They referred to the works of McCullough for the idea of the proof, however to the best of our knowledge prior to this work the proof of this fundamental fact was not given in literature or in a preprint form. Our proof is based on different ideas. For M = (S1 × S2)# M′ we construct K in M such that |K| = 2 ≠ ∞.
TRADE-OFF BASED NEGOTIATION OF TRAFFIC CONDITIONING AND SERVICE LEVEL AGREEMENTS IN DIFFSERV NETWORKS
Authors: COMUZZI MARCO , FRANCALANCI CHIARA , GIACOMAZZI PAOLO
Published: September 2005

The paper faces the problem of the runtime negotiation on the Traffic Conditioning Agreement and Service Level Agreement in IP Differentiated Services networks. A first contribution of the paper with respect to previous literature is to propose a multi-attribute description of QoS targets and traffic profile. A second contribution of this work is to provide a mathematical formalization of the negotiation problem suitable for automated negotiation. The model is tested through simulation to a) verify the convergence of the negotiation process, which is critical to ensure that negotiation can be performed automatically and b) analyze the agreement solutions that are reached by negotiation parties for different values of quality of service and price parameters. With this paper's negotiation model, the primary goal of negotiating parties is to maintain the value of their utility function constant by searching a trade-off between QoS and price. However, the willingness to cooperate of the negotiating parties has a strong impact on the agreement value of negotiation parameters.
IMPLEMENTATION OF A PURE P2P COLLABORATION MULTIPLATFORM AND ITS APPLICATIONS
Authors: NAKAMURA NOBUHIRO , BAROLLI LEONARD , TAKAHAMA SOUICHIROU , SUGITA KAORU , MA JIANHUA , DURRESI ARJAN
Published: September 2005

Peer-to-Peer (P2P) computing offers many attractive features, such as collaboration, self-organization, load balancing, availability, fault tolerance and anonymity. However, it also faces many serious challenges. In our previous work, we implemented a synchronous P2P collaboration platform called TOMSCOP. Based on the elementary peer group services offered by the JXTA general framework, TOMSCOP provides four types of services: synchronous message transportation, peer room administration, peer communication support and application space management. By using the four services, different kinds of shared applications for various specific purposes can be relatively easily developed and associated collaborative cyber spaces or communities can be quickly built across the JXTA virtual network overlaid on top of the existing physical networks. However, the TOMSCOP was implemented only in Windows XP OS. In this paper, we extend our previous work and present the implementation of a Multi-Platform P2P System (MPPS). The proposed system operates very smoothly in UNIX Solaris 9 OS, LINUX Suse 9.1 OS, Mac OSX, Windows XP and NetBSD.
CBF: LOOK-UP PROTOCOL FOR DISTRIBUTED MULTIMEDIA OBJECTS IN PEER-TO-PEER OVERLAY NETWORKS
Authors: WATANABE KENICHI , HAYASHIBARA NAOHIRO , TAKIZAWA MAKOTO
Published: September 2005

Various types of applications take usage of multimedia objects like music and movies. Multimedia objects are distributed in peer-to-peer (P2P) overlay networks since the objects are downloaded and personalized in computers, mainly personal computers interconnected with the Internet. An application would like to take some service of a target object. A target peer is a peer which can manipulate a target object. First, the application has to find target peers which can support enough quality of service (QoS) of target multimedia objects. Due to the scalability and variety of peers in P2P overlay networks, it is difficult, possibly impossible to maintain a centralized directory showing in which peer each object is distributed. In this paper, we newly take an acquaintance approach where each peer maintains its acquaintance peers. An acquaintance peer of a peer p is a peer whose service the peer p knows and with which the peer p can directly communicate in P2P overlay networks. We discuss types of acquaintance relations of peers with respect to what objects each peer holds, is allowed to manipulate, and can grant access rights on. In addition, we discuss a new type of flooding algorithm named charge-based flooding (CBF) algorithm to find target peers based on charge and acquaintance concepts so that areas in P2P overlay networks where target peers are expected to exist are more deeply searched. We evaluate the charge-based flooding (CBF) algorithm compared with a traditional TTL-based flooding algorithm in terms of the number of messages transmitted in networks.
QUANTIFYING THE TIME-CLUSTERING IN SGR1806-20 BURSTS
Authors: TELESCA LUCIANO
Published: September 2005

The time-clustering behavior of the neutron star SGR1806-20 burst sequence (detected by the International Cometary Explorer, ICE) has been analyzed. The presence of two different timescaling regions, related to the "foreshock" and "aftershock" phases, separated by the largest event occurred on November 16, 1983, 8:34 GMT, E = 5.17 · 1041 erg , has been evidenced. The results highlight that starquake foreshocks involve medium timescales from about 30 minutes to approximately 5 days, while starquake aftershocks involve longer timescales ranging up 4 months.
3D WAVELET TREATMENT OF SOLVATED BIPOLARON AND POLARON
Authors: CHUEV G. N. , FEDOROV M. V. , LUO H. J. , KOLB D. , TIMOSHENKO E. G.
Published: September 2005

Three-dimensional discrete tensor wavelets are applied to calculate wave functions of excess electrons solvated in polar liquids. Starting from the Hartree–Fock approximation for the electron wave functions and from the linear response to the solute charge for the solvent, we have derived the approximate free energy functional for the excess electrons. The orthogonal Coifman basis set is used to minimize the free energy functional and to approximate the electron wave functions. The scheme is applied to the calculation of the properties of the solvated electron and the singlet bipolaron formation. The obtained results indicate that the proposed algorithm is fast and rather efficient for calculating the electronic structure of the solvated molecular solutes.
QSPR STUDY ON DIRECT PHOTOLYSIS HALF-LIVES OF PAHs IN WATER SURFACE
Authors: LU GUI-NING , DANG ZHI , TAO XUE-QIN , PENG PING-AN , ZHANG DE-CONG
Published: September 2005

Quantitative structure-property relationship (QSPR) modeling is a helpful approach used to correlate the properties of pollutants with their structure descriptors. In this paper a QSPR model for direct photolysis half-lives of polycyclic aromatic hydrocarbons (PAHs) under sunlight on the water surface was developed using density functional theory (DFT) and direct photolysis half-lives of seven PAHs without reported observed values were predicted. The quantum chemical descriptors used in this study were computed at the level of B3LYP/6–311+G(d) and analyzed by partial least squares (PLS) method. The obtained QSPR model with a correlation coefficient of 0.963 was more significant than that derived from semi-empirical molecular orbital algorithm in literatures. It was found that the eigenvalues of the frontier molecular orbital (E HOMO , E LUMO , E NLUMO and E NHOMO ) are important in governing the photolysis half-lives of PAHs in water surface, while the molecular weight (MW) and molecular total energy (TE) also have great effects on photolysis half-lives. The importance of E NLUMO and E NHOMO in the model complicates the photolytic mechanism of PAHs and they might become two useful descriptors in QSPR study on photolysis.
SIMULATION OF CO CHEMISORPTION ON Pt SUPPORTED ON FRACTAL SURFACES
Authors: DOBRESCU GIANINA , FANGLI IUDIT , RUSU MIRCEA
Published: September 2005

CO chemisorption on Pt supported on fractal surfaces was simulated in order to compute chemisorption dimension and active sites fractal dimension. Pt deposition was simulated using different models on both fractal and planar surfaces. The potential energy surface with two adsorption positions model was used to compute Pt–CO interaction and a Lennard–Jones 6–12 potential was used to simulate CO–CO interaction. Two Pt phases on fractal surface, one at low concentration — the dispersed phase and the second at high concentration — the aggregated phase characterized by weak interactions with support are obtained. The results are in accord with experimental data of CO chemisorption on Pt supported on γ-alumina. Computed data obtained for planar support are compared with those obtained on fractal support. The effect of fractal support on chemisorption data is underlined.
THE ROLE OF OXIDATION STATES IN LASER LIGHT GENERATION AND COLOR IMAGE FORMATION (II) ANAB INITIOSTUDY OF FA:Hg+AND FA:Hg++COLOR CENTERS AT THE LOW COORDINATION (100) AND (110) SURFACES OFAgBrCRYSTAL
Authors: SHALABI A. S. , EID Kh. M.
Published: September 2005

The oxidation states of mercury in FA: Hg+and FA: Hg++color centers at the low coordination (100) and (110) surfaces of AgBr play important roles in laser light generation and color image formation. Two simultaneous potentials at these surfaces were investigated by using quantum mechanical ab initio methods. Quantum clusters of variable sizes were embedded in the simulated Coulomb fields that closely approximate the Madelung fields of the host surfaces, and ions that were the nearest neighbors to the FA– defect site were allowed to relax to equilibrium. The calculated Stokes shifts suggest that laser light generation is sensitive to the simultaneous effects of the oxidation state of mercury, the coordination number of the surface ion, and the choice of the basis set centered on the anion vacancy. An attempt has been made to explain these effects in terms of Madelung potential, electron affinity and optical–optical conversion efficiency. All relaxed excited states of the defect-containing surfaces were deep below the lower edges of the conduction bands of the ground state defect-free surfaces, suggesting that the FA: Hg+and FA: Hg++centers are suitable laser defects. The dependence of the orientational destruction, recording sensitivity and exciton (energy) transfer on the oxidation state of mercury and the coordination number of the surface ion on is clarified. The Glasner–Tompkins empirical rule is generalized to include the oxidation state of the impurity cation and the coordination number of the surface ion. As far as color image formation is concerned, the supersensitizer was found to increase the sensitizing capabilities of two primary dyes in the excited states by increasing the relative yield of quantum efficiency. The Hg++surfaces of AgBr are significantly more sensitive than the corresponding surfaces. On the basis of quasi Fermi levels, the difference in the sensitizing capabilities between the examined dyes in the excited states is determined.
THEORETICAL CHARACTERIZATION OF A HIGHLY ELECTROPHILIC CARBENE
Authors: VAN DER MAELEN URÍA JUAN F. , RUIZ JAVIER , GARCÍA-GRANDA SANTIAGO
Published: September 2005

The experimental geometry obtained from single-crystal X-ray diffraction data for a metalladiphosphanyl carbene precursor is compared with the results of theoretical calculations made at the ab initio level by using Hartree–Fock (HF) and Density Functional Theory (DFT) methods over the carbene itself. Theoretical geometry optimizations for the singlet ground state of [ Mn(CO)4(PH2)2C: ]+ have been performed with several hybrid functionals and basis sets. Calculated geometries showed a perfect C 2v symmetry in the highest levels of calculation and were somewhat relaxed when compared with the experimental ones; for instance, with the largest basis set, the P–C–P angle found was 124.8°, whereas C–P bond distances were both 1.667 Å, compared to 103.5(3)° and 1.718(5) Å, respectively, from the experimental data. The absence of a ligand attached to the C : atom in the calculated structure, which is present in the form of iodine in the experimental complex, is probably responsible, to a certain extent, for the discrepancies. In addition to the structural computations, in order to theoretically quantify the highly electrophilic character expected for the carbene, electron affinities were calculated and found to be between 6.24 eV and 6.97 eV at different DFT levels of calculation, which confirmed the expectations. In this respect, a comparison with the analogous [Ru(CNH)4(PH2)2C:]2+ carbene is also made, showing the possibility of experimentally trapping the manganese carbene.
ENVIRONMENTAL MANAGEMENT SYSTEMS IN RAIL OPERATION AND MAINTENANCE: CURRENT PRACTICE AND POTENTIAL IMPROVEMENTS
Authors: LUNDBERG KRISTINA , BALFORS BERIT , FOLKESON LENNART
Published: September 2005

Environmental management systems (EMS) require performance evaluation of significant environmental aspects. Much has been published on how to achieve environmental performance evaluation but little information is available on applications in practice. The Swedish National Rail Administration, Banverket, initiated the implementation of EMS in 1998, at about the same time as many other rail administrations. In this paper an overview of the application of EMS at rail administrations in selected countries is presented and systems for environmental performance evaluation within the EMS used by Banverket are analysed. The use of EMS by rail administrations was found to vary from the absence of environmental management to fully implemented EMS, mainly ISO 14001. At Banverket, EMS is widely used but the environmental performance evaluation could be improved by introducing indicators and merging all types of environmental monitoring, currently reported separately, into a common system.
NUCLEAR AND MITOCHONDRIAL COMPARTMENTATION OF OXIDATIVE STRESS AND REDOX SIGNALING
Authors: Hansen Jason M. , Go Young-Mi , Jones Dean P.
Published: September 2005

▪ Abstract  New methods to measure thiol oxidation show that redox compartmentation functions as a mechanism for specificity in redox signaling and oxidative stress. Redox Western analysis and redox-sensitive green fluorescent proteins provide means to quantify thiol/disulfide redox changes in specific subcellular compartments. Analyses using these techniques show that the relative redox states from most reducing to most oxidizing are mitochondria > nuclei > cytoplasm > endoplasmic reticulum > extracellular space. Mitochondrial thiols are an important target of oxidant-induced apoptosis and necrosis and are especially vulnerable to oxidation because of the relatively alkaline pH. Maintenance of a relatively reduced nuclear redox state is critical for transcription factor binding in transcriptional activation in response to oxidative stress. The new methods are applicable to a broad range of experimental systems and their use will provide improved understanding of the pharmacologic and toxicologic actions of drugs and toxicants.
INSIGHTS ON TRP CHANNELS FROM IN VIVO STUDIES IN DROSOPHILA
Authors: Minke Baruch , Parnas Moshe
Published: September 2005

▪ Abstract  Transient receptor potential (TRP) channels mediate responses in a large variety of signaling mechanisms. Most studies on mammalian TRP channels rely on heterologous expression, but their relevance to in vivo tissues is not entirely clear. In contrast, Drosophila TRP and TRP-like (TRPL) channels allow direct analyses of in vivo function. In Drosophila photoreceptors, activation of TRP and TRPL is mediated via the phosphoinositide cascade, with both Ca2+ and diacylglycerol (DAG) essential for generating the light response. In tissue culture cells, TRPL channels are constitutively active, and lipid second messengers greatly facilitate this activity. Inhibition of phospholipase C (PLC) completely blocks lipid activation of TRPL, suggesting that lipid activation is mediated via PLC. In vivo studies in mutant Drosophila also reveal an acute requirement for lipid-producing enzyme, which may regulate PLC activity. Thus, PLC and its downstream second messengers, Ca2+ and DAG, constitute critical mediators of TRP/TRPL gating in vivo.
Analysis of Longitudinal Data: The Integration of Theoretical Model, Temporal Design, and Statistical Model
Authors: Collins Linda M.
Published: September 2005

This article argues that ideal longitudinal research is characterized by the seamless integration of three elements: (a) a well-articulated theoretical model of change observed using (b) a temporal design that affords a clear and detailed view of the process, with the resulting data analyzed by means of (c) a statistical model that is an operationalization of the theoretical model. Two general varieties of theoretical models are considered: models in which the time-related change of primary interest is continuous, and those in which it is characterized by movement between discrete states. In addition, two general types of temporal designs are considered: the longitudinal panel design and the intensive longitudinal design. For each general category of theoretical models, some of the analytic possibilities available for longitudinal panel designs and for intensive longitudinal designs are discussed. The article concludes with brief discussions of two issues particularly relevant to longitudinal research—missing data and measurement—and a few words about exploratory research.
Hypothalamic paraventricular nucleus, but not vasopressin, participates in chronic hyperactivity of the HPA axis in diabetic rats
Authors: Zelena Dóra , Filaretova Ludmila , Mergl Zsuzsa , Barna István , Tóth Zsuzsanna E. , Makara Gábor B.
Published: September 2005

Diabetes mellitus (DM), as chronic stress activates the hypothalamo-pituitary-adrenocortical axis. We examined whether arginine vasopressin (AVP) and the hypothalamic paraventricular nucleus (PVN) participate in DM-induced chronic stress symptoms. AVP-deficient Brattleboro or PVN-lesioned Wistar rats were used with heterozygous or sham-operated controls. The rats were studied 2 wk after a single injection of streptozotocin. The appearance of DM (enhanced water consumption and blood glucose elevation) and the chronic stress-like somatic changes (body weight decrease, thymus involution, adrenal gland hypertrophy) were not influenced by the lack of AVP. By contrast, PVN lesion significantly attenuated DM-induced thymus involution and adrenal gland hypertrophy as well as the increase in water consumption. The corticotropin-releasing hormone mRNA in PVN was diminished by DM and elevated by the lack of AVP without interaction. DM elevated the proopiomelanocortin (POMC) mRNA in the anterior lobe of the pituitary. The lack of AVP had no effect, whereas lesioning the PVN significantly diminished the elevation. The elevated basal corticosterone plasma levels detectable in DM were influenced neither by the lack of AVP nor by lesioning the PVN. Thus the lack of AVP had no influence on DM-induced chronic stress symptoms, but lesioning the PVN attenuated part of them. However, the lack of elevation in POMC mRNA after PVN lesion, together with the maintained corticosterone elevation, suggests that direct adrenal gland activation occurs in untreated DM.
Cadmium reduces 11β-hydroxysteroid dehydrogenase type 2 activity and expression in human placental trophoblast cells
Authors: Yang Kaiping , Julan Laura , Rubio Fran , Sharma Anju , Guan Haiyan
Published: September 2005

Cadmium, a common environmental pollutant and a major constituent of tobacco smoke, has been identified as a new class of endocrine disruptors with a wide range of detrimental effects on mammalian reproduction. During human pregnancy, maternal cadmium exposure, via the environment and/or cigarette smoking, leads to fetal growth restriction (FGR), but the underlying mechanisms are unknown. Although a substantial amount of evidence suggests that cadmium may affect fetal growth indirectly via the placenta, the molecular targets remain to be identified. Given that reduced placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2, encoded by HSD11B2 gene) is causally linked to FGR, the present study was undertaken to examine the hypothesis that cadmium induces FGR in part by targeting placental HSD11B2. Using cultured human trophoblast cells as a model system, we showed that cadmium exposure resulted in a time- and concentration-dependent decrease in 11β-HSD2 activity, such that an 80% reduction was observed after 24-h treatment at 1 μM. It also led to a similar decrease in levels of 11β-HSD2 protein and mRNA, suggesting that cadmium reduced 11β-HSD2 expression. Furthermore, cadmium diminished HSD11B2 promoter activity, indicative of repression of HSD11B2 gene transcription. In addition, the effect of cadmium was highly specific, in that other divalent metals (Zn2+, Mg2+, and Mn2+) as well as nicotine and cotinine (a major metabolite of nicotine) did not alter 11β-HSD2 activity. Taken together, these findings demonstrate that cadmium reduces human placental 11β-HSD2 expression and activity by suppressing HSD11B2 gene transcription. Thus the present study identifies placental 11β-HSD2 as a novel molecular target of cadmium. It also reveals a molecular mechanism by which this endocrine disruptor may affect human placental function and, consequently, fetal growth and development.