bluuebunny/crossref_metadata_2025 huggingface dataset:
Organotin contamination, imposex and androgen/oestrogen ratios in natural populations of Nassarius reticulatus along a ship density gradient
Authors: Barroso C. M. , Reis‐Henriques M. A. , Ferreira M. , Gibbs P. E. , Moreira M. H.
Published: October 2005

Levels of organotin body burden (expressed as tin), imposex and steroid hormones (testosterone, 17β‐oestradiol, testosterone glucuronide and sulfate conjugates) were investigated in natural populations of Nassarius reticulatus in the Ria de Aveiro (northwest Portugal) between 1997 and 1999. The tributyltin (TBT) whole body burden (b.b.) of females presented increasing gradients from the adjacent open coast (16–26 ng g−1 dry weight (d.w.)) towards the ports inside the Ria de Aveiro (195–272 ng g−1 d.w.). Triphenyltin b.b. was only detected at the most polluted port (22 ng g−1 d.w.). Imposex also presented increasing values from the adjacent coast (vas deferens sequence index (VDSI): 0.0–0.5; relative penis length index (RPLI): 0.0–2.4; penis length index (PLI): 0.0–0.3 mm; percentage of affected females (%I): 0–30) towards the ports (VDSI: 3.8–4.8; RPLI: 51–80; PLI: 6.7–10.8 mm; %I: 100). The testosterone levels in females without imposex were always lower than in females with imposex, and the ratio of testosterone/17β‐oestradiol in females tended to increase with increasing imposex and organotin contamination. In spite of the large difference in the female testosterone and 17β‐oestradiol levels between summer and winter, related to the reproductive cycle, the spatial trend of the testosterone/17β‐oestradiol ratio was remarkably similar in shape and values in the two seasons. Imposex was significantly correlated with the TBT b.b. and the testosterone/17β‐oestradiol ratio in females. The testosterone conjugate levels did not show any clear pattern with the increasing values of imposex and TBT contamination. Copyright © 2005 John Wiley & Sons, Ltd.
Electrocatalytic oxidation of sulfite by acetylferrocene at glassy carbon electrode
Authors: Gao Zuo‐Ning , Ma Jin‐Fu , Liu Wan‐Yi
Published: October 2005

The electrochemical oxidation of sulfite catalyzed by acetylferrocene (AFc) at a glassy carbon electrode (GCE) in 0.2 M NaClO4 aqueous solution has been studied by cyclic voltammetry. Although sulfite itself showed a sluggish electrochemical response at the GCE, the response could be enhanced greatly by using AFc as a mediator, which enables a sensitive determination of the substrate (sulfite). The reaction rate constant for catalytic oxidation was evaluated as (7.02 ± 0.05) × 104 M−1 s−1 by chronoamperometry. Experimental conditions that maximize the current efficiency of the electrocatalytic oxidation, such as the pH and both the catalyst (AFc) and substrate (sulfite) concentrations, were also investigated. The electrochemical kinetics of electrocatalytic oxidation of sulfite by AFc has been studied by cyclic voltammetry. In the presence of 5 × 10−4 M AFc, the oxidation current is proportional to the sulfite concentration and the calibration plot was linear over the concentration range 2 × 10−4–2.4 × 10−3 M. This result can be applied in the determination of real samples. Copyright © 2005 John Wiley & Sons, Ltd.
On the reactivity of platina‐β‐diketones: a straightforward synthesis of trans‐acetylchlorobis(phosphine)platinum(II) complexes and their reactivity
Authors: Albrecht Christian , Wagner Christoph , Merzweiler Kurt , Lis Tadeusz , Steinborn Dirk
Published: October 2005

The platina‐β‐diketone [Pt2{(COMe)2H}2(µ‐Cl)2] (1) was found to react with monodentate phosphines to yield acetyl(chloro)platinum(II) complexes trans‐[Pt(COMe)Cl(PR3)2] (PR3 = PPh3, 2a; P(4‐FC6H4)3, 2b; PMePh2, 2c; PMe2Ph, 2d; P(n‐Bu)3, 2e; P(o‐tol)3, 2f; P(m‐tol)3, 2g; P(p‐tol)3, 2h). In the reaction with P(o‐tol)3 the methyl(carbonyl)platinum(II) complex [Pt(Me)Cl(CO){P(o‐tol)3}] (3a) was found to be an intermediate. On the other hand, treating 1 with P(C6F5)3 led to the formation of [Pt(Me)Cl(CO){P(C6F5)3}] (3b), even in excess of the phosphine. Phosphine ligands with a lower donor capability in complexes 2 and the arsine ligand in trans‐[Pt(COMe)Cl(AsPh3)2] (2i) proved to be subject to substitution by stronger donating phosphine ligands, thus forming complexes trans‐[Pt(COMe)Cl(L)L′] (L/L′ = AsPh3/PPh3, 4a; PPh3/P(n‐Bu)3, 4b) and cis‐[Pt(COMe)Cl(dppe)] (4c). Furthermore, in boiling benzene, complexes 2a–2c and 2i underwent decarbonylation yielding quantitatively methyl(chloro)platinum(II) complexes trans‐[Pt(Me)Cl(L)2] (L = PPh3, 5a; P(4‐FC6H4)3, 5b; PMePh2, 5c; AsPh3, 5d). The identities of all complexes were confirmed by 1H, 13C and 31P NMR spectroscopy. Single‐crystal X‐ray diffraction analyses of 2a·2CHCl3, 2f and 5b showed that the platinum atom is square‐planar coordinated by two phosphine ligands (PPh3, 2a; P(o‐tol)3, 2f; P(4F‐C6H4)3, 5b) in mutual trans position as well as by an acetyl ligand (2a, 2f) and a methyl ligand (5b), respectively, trans to a chloro ligand. Single‐crystal X‐ray diffraction analysis of 3b exhibited a square‐planar platinum complex with the two π‐acceptor ligands CO and P(C6F5)3 in mutual cis position (configuration index: SP‐4‐3). Copyright © 2005 John Wiley & Sons, Ltd.
Influence of metal core of mixed‐metal carboxylates in preparation of spinel: ZnFe2O(O2CCF3)6 as a single‐source precursor for preparation of ZnFe2O4
Authors: Amini M. M. , Yadavi M.
Published: October 2005

The mixed‐metal and mixed‐valance carboxylates of MFe2O(O2CCF3)6(C4H8O)2(H2O) (M = Zn, Mn, Cu) and MFe2O(O2CCCl3)6(C4H8O)2(H2O) (M = Zn, Fe) were utilized as potential precursors for the preparation of spinel. In the pyrolysis of ZnFe2O(O2CCF3)6(C4H8O)2(H2O) in air at 400 °C pure ZnFe2O4 is formed, in contrast to pyrolysis of the trichloro derivative, which resulted in the formation of ZnO and Fe2O3. In the pyrolysis of MnFe2O(O2CCF3)6(C4H8O)2(H2O) in nitrogen, MnFe2O4 was the main phase and single oxides were the minor phases. Copyright © 2005 John Wiley & Sons, Ltd.
On the Importance of Carbohydrate–Aromatic Interactions for the Molecular Recognition of Oligosaccharides by Proteins: NMR Studies of the Structure and Binding Affinity of AcAMP2‐like Peptides with Non‐Natural Naphthyl and Fluoroaromatic Residues
Authors: Chávez M. Isabel , Andreu Cecilia , Vidal Paloma , Aboitiz Nuria , Freire Felix , Groves Patrick , Asensio Juan Luis , Asensio Gregorio , Muraki Michiro , Cañada Francisco Javier , Jiménez‐Barbero Jesús
Published: October 2005

The specific interaction of a variety of modified hevein domains to chitooligosaccharides has been studied by NMR spectroscopy in order to assess the importance of aromatic–carbohydrate interactions for the molecular recognition of neutral sugars. These mutant AcAMP2‐like peptides, which have 4‐fluoro‐phenylalanine, tryptophan, or 2‐naphthylalanine at the key interacting positions, have been prepared by solid‐phase synthesis. Their three‐dimensional structures, when bound to the chitin‐derived trisaccharide, have been deduced by NMR spectroscopy. By using DYANA and restrained molecular dynamics simulations with the AMBER 5.0 force field, the three‐dimensional structures of the protein–sugar complexes have been obtained. The thermodynamic analysis of the interactions that occur upon complex formation have also been carried out. Regarding binding affinity, the obtained data have permitted the deduction that the larger the aromatic group, the higher the association constant and the binding enthalpy. In all cases, entropy opposes binding. In contrast, deactivation of the aromatic rings by attaching fluorine atoms decreases the binding affinity, with a concomitant decrease in enthalpy. The role of the chemical nature of the aromatic ring for establishing sugar contacts has been thus evaluated.
Electron‐Rich Diferrous–Phosphane–Thiolates Relevant to Fe‐only Hydrogenase: Is Cyanide “Nature's Trimethylphosphane”?
Authors: van der Vlugt Jarl Ivar , Rauchfuss Thomas B. , Wilson Scott R.
Published: October 2005

The two‐step one‐pot oxidative decarbonylation of [Fe2(S2C2H4)(CO)4(PMe3)2] (1) with [FeCp2]PF6, followed by addition of phosphane ligands, led to a series of diferrous dithiolato carbonyls 2–6, containing three or four phosphane ligands. In situ measurements indicate efficient formation of 12+ as the initial intermediate of the oxidation of 1, even when a deficiency of the oxidant was employed. Subsequent addition of PR3 gave rise to [Fe2(S2C2H4)(μ‐CO)(CO)3(PMe3)3]2+ (2) and [Fe2(S2C2H4)(μ‐CO)(CO)2(PMe3)2(PR3)2]2+ (R=Me 3, OMe 4) as principal products. One terminal CO ligand in these complexes was readily substituted by MeCN, and [Fe2(S2C2H4)(μ‐CO)(CO)2(PMe3)3(MeCN)]2+ (5) and [Fe2(S2C2H4)(μ‐CO)(CO)(PMe3)4(MeCN)]2+ (6) were fully characterized. Relevant to the Hred state of the active site of Fe‐only hydrogenases, the unsymmetrical derivatives 5 and 6 feature a semibridging CO ligand trans to a labile coordination site.
Mechanistic Investigation of the 2,5‐Diphenylpyrrolidine‐Catalyzed Enantioselective α‐Chlorination of Aldehydes
Authors: Halland Nis , Alstrup Lie Mette , Kjærsgaard Anne , Marigo Mauro , Schiøtt Birgit , Jørgensen Karl Anker
Published: October 2005

The mechanism for the 2,5‐diphenylpyrrolidine‐catalyzed enantioselective α‐chlorination of aldehydes with electrophilic halogenation reagents has been investigated by using experimental and computational methods. These studies have led us to propose a mechanism for the reaction that proceeds through an initial N‐chlorination of the chiral catalyst–substrate complex, followed by a 1,3‐sigmatropic shift of the chlorine atom to the enamine carbon atom. The suggested reaction course is different from previously proposed mechanisms for organocatalytic enamine reactions, in which the carbon–electrophile bond is formed directly. Furthermore, the rate‐determining step in the overall reaction was determined and the presence of nonlinear effects was probed.
Metal Aminocarboxylate Coordination Polymers with Chain and Layered Structures
Authors: Dan Meenakshi , Rao C. N. R.
Published: October 2005

The synthesis and structures of metal aminocarboxylates prepared in acidic, neutral, or alkaline media have been explored with the purpose of isolating coordination polymers with linear chain and two‐dimensional layered structures. Metal glycinates of the formulae [CoCl2(H2O)2(CO2CH2NH3)] (I), [MnCl2(CO2CH2NH3)2] (II), and [Cd3Cl6(CO2CH2NH3)4] (III) with one‐dimensional chain structures have been obtained by the reaction of the metal salts with glycine in an acidic medium under hydro/solvothermal conditions. These chain compounds contain glycine in the zwitterionic form. 4‐Aminobutyric acid transforms to a cyclic amide under such reaction conditions, and the amide forms a chain compound of the formula [CdBr2(C4H7NO)2] (IV). Glycine in the zwitterionic form also forms a two‐dimensional layered compound of the formula [Mn(H2O)2(CO2CH2NH3)2]Br2 (V). 6‐Aminocaproic acid under alkaline conditions forms layered compounds with metals at room temperature, the metal being coordinated both by the amino nitrogen and the carboxyl oxygen atoms. Of the two layered compounds [Cd{CO2(CH2)5NH2}2]⋅2 H2O (VI) and [Cu{CO2(CH2)5NH2}2]⋅2 H2O (VII), the latter has voids in which water molecules reside.
Assembly of Au Nanoparticles with Anisotropic Optical Property Directed by 2′‐Phosphorothioate Oligo‐DNA
Authors: Yang Bai‐Quan , Jiang Lin , Zhuang Jia‐Qi , Liu Yi‐Chun , Xu Wu , Li Tie‐Jin
Published: October 2005

Two complemental 2′‐phosphorothioate oligo‐DNA compounds were used as linker molecules to provide the necessary symmetry‐breaking mechanism to direct the assembly of 13 nm Au nanoparticles into aggregates with anisotropic optical properties.
Study on Thermochemistry and Thermal Decomposition Kinetics of Dy(Tyr)(Gly)3Cl3·3H 2O
Authors: Zhang Zhong‐Hai , Ku Zong‐Jun , Liu Yi , Qu Song‐Sheng
Published: October 2005

The complex of dysprosium chloride with glycine and L‐tyrosine, Dy(Tyr)(Gly)3Cl3· 3H2O, was synthesized and characterized. The standard molar formation enthalpy of Dy(Tyr)(Gly)3Cl3· 3H2O at T=298.15 K was determined to be (‐4287.10±2.14) kJ/mol. The kinetics of thermal decomposition of the complex was studied by non‐isothermal TG‐DTG curves. The kinetic parameters and mechanism function of the thermal decomposition reaction for its second step were proposed. The kinetic equation could be expressed as: dα/dT=3.14×1020s‐1/βexp(‐209.37 kJ·mol‐1/RT)(1−α) 2.
Preparation and Electrochemical Properties of Manganese Hexacyanoferrate Modified Glassy Carbon Electrode
Authors: Liu You‐Qin , Yan Yun , Shen Han‐Xi
Published: October 2005

A thin film of manganese hexacyanoferrate (MnHCF) was electrochemically formed on a glassy carbon (GC) electrode to prepare a chemically modified electrode (CME). The mechanism of film formation of MnHCF and its growth process were investigated in detail by cyclic voltammetry. The results show that the stoichiometric composition of MnHCF is MnIIIFeIII(CN)6, an analogue of prussian yellow. There exist three clear‐cut stages in the whole modification process and the last stage is indispensable to the fabrication of homogenized, stable MnHCF film and must last for an appropriate time. The surface morphology of MnHCF/GC electrode was characterized by scanning electron microscopy (SEM), which further verified the effective deposition of MnHCF film on GC. The kinetic constants of MnHCF/GC electrode process were also evaluated. The resulting MnHCF film modified electrode presented good stability and high electrocatalytic activity toward the oxidation of H2O2, indicating that MnHCF film possesses function of catalase and can be expected for analytical purposes.
Applications of Simple Estimation Scheme of Electron Correlation Energy to Strong Ionic Compounds
Authors: Zhuo Shu‐Ping , Wei Ji‐Chong , Ju Guan‐Zhi
Published: October 2005

The calculation results of electron correlation energies of KF and (KF)2 were reported. The transferability of lsK2, lsF2 and the inner core correlation effects of K and F in both K, K+, KF and F, F‐, KF systems were investigated respectively. The correlation energy contributions of K and F component to KF system were calculated. By applying the simple estimation scheme to the calculation of the correlation energy of the strong ionic compound KF and (KF) 2, it was shown that such a powerful scheme could not only reach the chemical accuracy but also need little computational work.
Study on Modification and Test Technology of Nonexplosive and Irrestorable Fertilizer‐grade Ammonium Nitrate
Authors: Shen Li‐Jin , Wang Xu‐Guang
Published: October 2005

Based on a study of the relationship of ammonium nitrate (AN) explosion and its thermal stability, inert agents were added to AN for eliminating the explosive characteristic of AN and in order to be irrestorable. The results of using a large quantity of experiments and various testing technologies show that the improvement on thermal stability of modified AN is the basic reason for eliminating explosive characteristic of AN. The modification scheme was considered to have the following features: reliable and stable technology, market‐demanded product, low investment and good economic returns. And during the revamping period, the normal production of AN will not be affected, and the economic, social and environmental benefits are good.
AIM Study on Reaction HNCX → HXCN (X=O, S and Se)
Authors: Zeng Yan‐Li , Meng Ling‐Peng , Zheng Shi‐Jun
Published: October 2005

The reactions of HNCO to HOCN, HNCS to HSCN and HNCSe to HSeCN have been studied at MP2/6‐311+ +G(2df,pd)//B3LYP/6‐311+ +G(2df,pd) level. Geometries of the reactants, transition states and products have been optimized and geometries of the transition states are reported for the first time. The reasons why HNCO and HNCS instead of HOCN and HSCN were easily detected have been explained. It was predicted that HNCSe will be more easily detected than HSeCN. The breakage and formation of the chemical bonds in the reactions have been discussed by the topological analysis method of electronic density. The calculated results show that there are two kinds of structure transition states (STS) in reactions studied.
Crystal Structure and Bioactivity of Complex [Gd(C10H9N2O4)(C10H8N2O4)(H2O) 3]2·phen·4H2O
Authors: He Shui‐Yang , Yang Rui , Wu Wang‐Ting , Shi Qi‐Zhen , Wang Da‐Qi , An De‐Rong
Published: October 2005

A novel gadolinium(III) complex with N‐(2‐propionic acid)‐salicyloyl hydrazone (C10H10N2O4, H3L) and 1,10‐phenanthroline (C12H8N2, phen) was prepared and characterized. The crystal structure of [Gd(H2L)(HL)‐(H2O)3]2·phen·4H2O was determined by X‐ray single crystal diffractometry. The crystal complex crystallizes in the triclinic system with space group P‐1. There are two 9‐coordinated structure units in every complex molecule, in which Gd(III) is coordinated by two tridentate ligands (H2L and HL forms) and three water molecules and both the structural units take a distorted monocapped square antiprism. There is a free 1,10‐phenanthroline connecting with coordinated water by hydrogen bonds in the crystal. The bioactivity tests indicate that the complex is an inhibitor against three bacteria.
Studies of Iron‐Sulfur Covalency in the Model System and Proteins
Authors: Qin Xiu‐Juan , Chen Yan , Gao Fa‐Ming
Published: October 2005

It was found that the highly covalent nature of the metal‐ligand interactions in the Fe‐S cluster clearly played an important role in determining the reactivity of the sites. A semi‐empirical model, based on the Phillips theory of bonding was developed for quantitative explanation of covalency in Fe‐S cluster, showing that Mossbauer spectroscopy and electronic absorption spectroscopy provided the direct experimental probe of covalency of Fe‐S4 clusters.
Reduction of Nitrogen on Gallium Phosphide Nanoparticles
Authors: Zhang Zhao‐Chun , Cui De‐Liang
Published: October 2005

Under mild ambient conditions gallium phosphide (GaP) nanoparticles were employed to carry out the reduction of nitrogen. By using Nessler's reagent ammonia was detected in the slurry where the aggregated GaP particles were suspended in water and bubbled by pure nitrogen. Dependence of the concentration of ammonia upon bubbling time, velocity of the flow of nitrogen, and dosage of GaP particles was investigated. In comparison with the original GaP nanoparticles, the Raman scattering of the GaP particles undergoing the process of nitrogen fixation reveals that two sharp lines at 138 and 182 cm‐1, respectively, emerged from the broad continuum around 100–200 cm‐1. These two lines might be assigned to the translational motions of ammonia adsorbed on the surface of the GaP particles. An assessment of the infrared spectra of the two GaP particles led to the conclusion that the environment of the two H2O molecules was not identical. Analysis of the electron spin resonance results showed that the structure defect, gallium self‐interstitial, was not involved in the nitrogen fixation of the GaP nanoparticles.
One‐pot Synthesis ofN‐Hydroxylacridine Derivatives in Water
Authors: Shi Da‐Qing , Mou Jie , Zhuang Qi‐Ya , Wang Xiang‐Shan
Published: October 2005

N‐Hydroxylacridinedione derivatives were synthesized by three‐component reaction of aromatic aldehydes, 1,3‐dicarbonyl compounds and hydroxylamine hydrochloride using triethylbenzylammonium chloride (TEBA) as the catalysis in water. The reaction has many advantages including good yields, easy to be separated and environmental friendliness.
Asymmetric Synthesis of 5‐Hexadecanolide
Authors: Sun Bin , Zhang Chao‐Xin , Zhang Gui‐Min , Li Ying , Li Yu‐Lin , Peng Li‐Zeng
Published: October 2005

Optically pure S‐5‐hexadecanolide (1) has been easily prepared from readily available aldehyde 2 and cyclopentanone (3) using L‐proline‐catalyzed asymmetric aldol reactions as the key step.
In situSynthesis of Oligonucleotide and Detection of Gold‐label‐silver‐stain on PTFE Slices
Authors: Tan Mei‐Jun , Tang Jian‐Xin , Chen Hong
Published: October 2005

Poly(tetrafluoroethylene) (PTFE) was treated with plasma in a mixture of nitrogen and hydrogen (1:2 in volume). X‐ray photoelectron spectroscopy (XPS) demonstrated the success of amino group grafting. The as‐treated PTFE slices were successively applied to the in situ synthesis of oligonucleotides. With the detection of gold‐label‐silver‐stain, the hybridization signals were recorded with a gel document and analysis system. A target DNA concentration as low as 10 pmol/L could be detected. The complementary and mismatched sequences were distinguished clearly, and the ratio of background‐subtracted gray scale values for perfect match:1 base mismatch:2 base mismatch:3 base mismatch was 72:44.4:22.5:11.4. The sensitivity of in situ synthesis system was 1 order of magnitude higher than that of spotting system, and the signal of the former was about 1.5 times stronger than that of the latter under the same target DNA concentration. These plasma modified PTFE slices might open novel prospects for the in situ synthesis of DNA micro‐arrays.
Facile Synthesis and Characterization of Bioactive N‐[(1‐Ferrocenylethylidene)amino]‐ N′ ‐β‐D‐glycopyranosylthiourea
Authors: Zhang Shu‐Sheng , Yang Bo , Li Hui‐Xiang , Jiao Kui
Published: October 2005

Several novel N‐[(1‐ferrocenylethylidene)amino]‐N′ ‐β‐D‐glycopyranosylthioureas have been efficiently synthesized via a six‐step procedure, utilizing three monosaccharides (D‐glucose, D‐galactose and D‐xylose) as starting materials, respectively. They have been preliminarily determined to display biological activity against certain fungi. The target compounds have been unambiguously characterized by spectroscopic method and elemental analysis. An initially alternative synthetic route, which was seemingly reasonable, has been excluded due to its inefficiency.
Penta‐Coordinate Phosphorus Intermediates Analysis on Phospho‐related Proteins
Authors: Li Wu , Ma Yuan , Zhao Yu‐Fen
Published: October 2005

In this paper, based on known crystal structures of square pyramid (SP) and trigonal bipyramid (TBP) penta coordinated phosphorus compounds containing amino acid side chains, such as amino, carboxyl, hydroxyl or thiol, a software for survey the P(5)‐structure of phosphorylated proteins was derived. By this software, it was found that 382 of 398 phosphorus related kinases (96%) from current PDB could go through the penta‐coordinated phosphorus transition state or intermediate.
Precision radiotherapy for hemangiopericytomas of the central nervous system
Authors: Combs Stephanie E. , Thilmann Christoph , Debus Jurgen , Schulz‐Ertner Daniela
Published: October 2005

BACKGROUND

Radiotherapy (RT) plays a major role in the management of hemangiopericytomas (HAP). The present analysis evaluates the role of precision RT in the management of HAP of the central nervous system (CNS) and represents one of the largest series of HAP treated with RT that can be found in the literature.

METHODS

Of 37 consecutive patients with histologically confirmed HAP who were treated at the institution between 1984 and 2004, the majority, 25 tumors, was localized within the skull base (n = 25) and 4 tumors were localized at the spine. In 25 patients, high‐precision RT was delivered as fractionated stereotactic RT or intensity modulated RT. Median age at primary diagnosis was 40.5 years (range, 10–77 yrs). After primary diagnosis, surgical resection was performed in 23 patients. A median total dose of 54 Gy was delivered in a fractionation of 5 × 1.8–2 Gy per week. The median planning target volume was 58.2 mL (range, 10–412 mL). The median follow‐up time was 34 months (range, 3–166 mos).

RESULTS

Radiotherapy was well tolerated by all patients. Seventeen patients of this series remain alive. Overall survival rates at 5 and 10 years are 100% and 64%, respectively. Actuarial survival rates after RT were 85% and 69% at 3 and 5 years, respectively. Progression‐free survival after RT 80% and 61% at 3 and 5 years, respectively.

CONCLUSION

High‐precision RT is an effective and safe treatment modality for patients with HAP of the CNS and the spine and achieves highly acceptable tumor control, while sparing normal tissue. Cancer 2005. © 2005 American Cancer Society.
Matrix metalloproteinases in carcinoma of unknown primary
Authors: Karavasilis Vasilis , Malamou‐Mitsi Vasiliki , Briasoulis Evangelos , Tsanou Elena , Kitsou Evangelia , Kalofonos Haralambos , Fountzilas George , Fotsis Theodore , Pavlidis Nicholas
Published: October 2005

BACKGROUND

The purpose was to study proteolysis‐related molecules, matrix metalloproteinase‐2 (MMP‐2) and MMP‐9 and tissue inhibitor of metalloproteinases‐1 (TIMP‐1), in carcinoma of unknown primary (CUP).

METHODS

Paraffin‐embedded tumor material from 75 patients diagnosed with CUP was used. Tumor histologies were adenocarcinoma (77%), undifferentiated carcinoma (19%), and squamous cell carcinoma (4%) and patients were categorized into favorable (62%) and unfavorable (38%) subsets. The tissue expression of MMP‐2, MMP‐9, and TIMP‐1 was assessed by use of specific monoclonal antibodies and evaluated by means of a visual staining score. The expression of molecules studied was analyzed against clinicopathological data.

RESULTS

MMP‐2 was found expressed in 69% (strong expression in 49%), MMP‐9 in 49% (strong in 36%), and TIMP‐1 in 79% (strong in 44%) of studied cases. The expression of MMP‐2 correlated positively with MMP‐9. TIMP‐1 was significantly higher in unfavorable compared with favorable tumors and was associated with a shorter survival of patients (7.5 vs. 12 mos). No other associations were detected.

CONCLUSIONS

MMP‐2, MMP‐9, and TIMP‐1 are widely expressed in CUP, suggesting an essential role of proteolysis in these tumors. TIMP‐1 may be considered a possible marker of poor prognosis in CUP patients. Cancer 2005. © 2005 American Cancer Society.
Phase II study of carboxyamidotriazole in patients with advanced renal cell carcinoma refractory to immunotherapy
Authors: Dutcher Janice P. , Leon Larry , Manola Judith , Friedland David M. , Roth Bruce , Wilding George
Published: October 2005

BACKGROUND

The current study evaluated the response rate and 6‐month time to disease progression of the antiangiogenesis agent carboxyamidotriazole (CAI) in patients with metastatic renal cell carcinoma (RCC).

METHODS

Fifty‐seven patients with histologically confirmed metastatic RCC that progressed after biologic therapy (interferon or interleukin‐2) were enrolled. Four patients were ineligible. CAI was administered orally as a 28‐day cycle. Response and time to disease progression were evaluated.

RESULTS

Fifteen of 53 eligible patients received > 5 cycles, but 13 patients eventually discontinued treatment because of progressive disease. The majority of toxicities were Grade 1. However, Grade 3/4 toxicities did occur, the majority of which were gastrointestinal in nature. One of 47 patients evaluable achieved a partial response (1.9%) lasting 172 days. Six of 53 patients were alive and disease progression free at 6 months from the start of treatment (11.3%). The median overall survival was 12.5 months. The survival periods in the low‐risk, intermediate‐risk, and poor‐risk groups were 16.2 months, 20.9 months, and 5.8 months, respectively.

CONCLUSIONS

Patients in trials of second‐line therapy appear to have a better prognosis than previously considered, in part because they are eligible for another clinical trial. CAI was found to have little to no effect on the natural history of progressive RCC. Cancer 2005. © 2005 American Cancer Society.
VEGF as a predictive marker of rectal tumor response to preoperative radiotherapy
Authors: Zlobec Inti , Steele Russell , Compton Carolyn C.
Published: October 2005

BACKGROUND

Neoadjuvant radiotherapy for rectal cancer may result in tumor downstaging or complete tumor regression leading to greater sphincter preservation. The identification of molecular predictive markers of tumor response to preoperative radiotherapy would provide an additional tool for selecting patients most likely to benefit from treatment. The aim of this study was to determine whether VEGF expression in preirradiation tumor biopsies is a useful predictive marker of tumor response in patients with rectal cancer undergoing preoperative radiotherapy.

METHODS

Immunohistochemistry for VEGF was performed on 59 preirradiation biopsies from patients with completely responsive (ypT0) or nonresponsive tumors after preoperative radiotherapy. VEGF positivity was evaluated using several scoring methods and the association between VEGF and tumor response was compared. The distribution of VEGF scores was obtained as well as the mean VEGF expression in the two response groups.

RESULTS

The mean VEGF expression in nonresponsive tumors (NR) was significantly greater than in completely responsive tumors (CR) (P = 0.0035). Nearly half (47%) of all CR tumors had a VEGF expression of 10% or less. Eleven tumors were negative (0% immunoreactivity) for the protein and all of these (100%) were complete responders. Fifty‐two percent of the NR tumors had VEGF scores of 80% or greater. The four scoring methods used to determine the association between VEGF and tumor response each produced significant results (P < 0.05).

CONCLUSIONS

The results of this study indicate that VEGF assessed immunohistochemically from preirradiation tumor biopsies may be a useful marker of rectal tumor response to preoperative radiotherapy. Cancer 2005. © 2005 American Cancer Society.
Crystal Structures, EPR Spectra, and Magnetic Properties of a Series of Ionic Multi‐Component Complexes [(TBPDA)2·(C60·–)·(D+)] (D = Cp*2Cr, Cp*2Co, TDAE)
Authors: Konarev Dmitri V. , Kovalevsky Andrey Yu. , Khasanov Salavat S. , Saito Gunzi , Otsuka Akihiro , Lyubovskaya Rimma N.
Published: October 2005

New ionic multi‐component complexes [(TBPDA)2·(C60·–)·(D+)] [TBPDA = N,N,N′,N′‐tetrabenzyl‐p‐phenylenediamine; D = decamethylchromocene (Cp*2Cr, 1) and decamethylcobaltocene (Cp*2Co, 2)] were obtained additionally to previously characterized [(TBPDA)2·(C60·–)·(TDAE·+)] [TDAE = tetrakis(dimethylamino)ethylene, 3]. The presence of D+, C60·–, and neutral TBPDA in 1–3 was proved by the IR and UV/Visible/NIR spectra. D+ and C60·– form loose layers in 1 and 3 and are spatially separated by bulky TBPDA molecules. The C60·– radical anions alternate in the layer with the phenylene groups of TBPDA to form π‐π stacking, whereas disordered Cp*2Cr+ cations are isolated in the voids formed by eight benzyl groups of TBPDA. The EPR spectra of the complexes show single Lorentzian lines with g = 2.2526 and ΔH = 215 mT (1), g = 1.9999 and ΔH = 6.7 mT (2), and g = 2.0009 and ΔH = 2.93 mT (3) at room temperature. The EPR signal of 2 was attributed to C60·– (Cp*2Co+ is diamagnetic) and those in 1 and 3 to resonating signals between C60·– (g = 1.9996–2.0000) and Cp*2Cr+ [an asymmetric EPR signal with g[perp] = 4.02(1) and g[par] = 2.001(1)] (1) or TDAE·+ (g = 2.0035; 3) due to indirect coupling. The EPR signals from 2 and 3 are split into two components below 50 and 60 K, respectively, which shift in the opposite directions (to lower and higher fields) with decreasing temperature. The magnetic moments of 1–3 decrease below 50–100 K. Both effects are associated with the formation of field‐induced short‐range antiferromagnetically ordered clusters. It is shown that the D+ cations do not noticeably affect this interaction. Most probably, it is realized mainly between C60·– spins within the layer and is mediated by the phenylene groups of TBPDA. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Kinetic Inertness and Electrochemical Behavior of Copper(II) Tetraazamacrocyclic Complexes: Possible Implications for in Vivo Stability
Authors: Woodin Katrina S. , Heroux Katie J. , Boswell C. Andrew , Wong Edward H. , Weisman Gary R. , Niu Weijun , Tomellini Sterling A. , Anderson Carolyn J. , Zakharov Lev N. , Rheingold Arnold L.
Published: October 2005

The kinetic inertness of copper(II) complexes of several carboxymethyl‐armed cyclams and cyclens in 5 M HCl have been determined confirming that the complex derived from cross‐bridged cyclam (Cu‐CB‐TE2A) is by far the most resistant to acid decomplexation. FT‐IR studies in D2O solution revealed its unique resistance to full carboxylate protonation and its retention of coordination by both pendant arms even in 1 M DCl. The X‐ray structure of its monoprotonated form, [Cu‐CB‐TE2AH]+, also established full coordination by both COO– and COOH pendant arms in the solid state. Cyclic voltammograms of four carboxymethyl pendant‐armed cyclam and cyclen complexes in aqueous solution were obtained with only Cu‐CB‐TE2A displaying a quasi‐reversible CuII/CuI reduction wave. These indicators correlate with the superior in vivo behavior of this complex and its bifunctional conjugate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Interaction Between Terminal Zinc–Porphyrins in a U‐Shaped Trimeric Porphyrin Array Bearing Chiral Amino Acid Tails
Authors: Arai Toru , Takei Kiyoshi , Ogawa Yoshifumi , Nishino Norikazu
Published: October 2005

A U‐shaped trimeric porphyrin array with a zinc/free‐base/zinc arrangement (5ZFZ) and its derivatives were synthesized in order to investigate the interacting porphyrins in organic solvents. The porphyrin array is comprised of an αα‐atropisomeric bis(ortho‐aminophenyl)porphyrin free‐base as the template, a pair of zinc–porphyrins at the termini, achiral glycine spacers linking the porphyrins, and chiral L‐leucine derivatives attached to the template in the opposite direction of the zinc–porphyrins. 1H NMR (high‐field shifts of some pyrrole signals), UV/Vis (split Soret band), and CD spectra (exciton‐coupled Cotton effect) show the close assembly of the terminal zinc–porphyrins of 5ZFZ in CDCl3 and CH2Cl2. In contrast, the characteristic spectra for the interacting porphyrins do not appear for the trimeric array with three free‐base porphyrins (5F3) and the dimeric array with a zinc/free‐base arrangement (9ZF). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Antimalarial Polyketide Cycloperoxides from the Marine SpongePlakortis simplex
Authors: Campagnuolo Claudio , Fattorusso Ernesto , Romano Adriana , Taglialatela‐Scafati Orazio , Basilico Nicoletta , Parapini Silvia , Taramelli Donatella
Published: October 2005

Three new (5–7) and two known (4 and 8) polyketide derivatives have been isolated from the Caribbean sponge Plakortis simplex. Their stereostructures have been determined by spectroscopic methods and chemical transformations that include Zn‐mediated reduction and Dess–Martin oxidation, and by application of Mosher’s method. The cycloperoxide derivatives plakortide Q (7) and compound 8 were evaluated for their in vitro antimalarial activity against chloroquine‐sensitive and chloroquine‐resistant strains of Plasmodium falciparum. The lower potency of these molecules relative to plakortin indicates that the change of configuration at C‐3 exerts negative effects on the antimalarial activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Ti‐Mediated Synthesis of Aminocyclopropyl‐Substituted Carbohydrates
Authors: Laroche Christophe , Behr Jean‐Bernard , Szymoniak Jan , Bertus Philippe , Plantier‐Royon Richard
Published: October 2005

Carbohydrates bearing aminocyclopropyl moieties were conveniently prepared from the corresponding nitriles by titanium‐mediated addition of Grignard reagents. A wide range of protective groups are tolerated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Spirangien A and B, Highly Cytotoxic and Antifungal Spiroketals from the Myxobacterium Sorangium cellulosum: Isolation, Structure Elucidation and Chemical Modifications
Authors: Niggemann Jutta , Bedorf Norbert , Flörke Ulrich , Steinmetz Heinrich , Gerth Klaus , Reichenbach Hans , Höfle Gerhard
Published: October 2005

Two novel highly cytotoxic metabolites, spirangien A (1) and B (2), were isolated from the myxobacterium Sorangium cellulosum (strain So ce90). The structures were elucidated by detailed NMR spectroscopic analysis. The previously unknown molecular framework common to spirangien A and B includes a highly functionalized spiroketal core structure, a side chain bearing a pentaene chromophore and a terminal carboxyl group, and a total of thirteen stereocenters. The absolute configuration at C‐3 was determined by degradation and subsequent fragment analysis by GC. The relative stereochemistry of the spiroketal structure was proposed on the basis of vicinal proton couplings and ROESY data for hydroperoxide derivative 4, obtained by ozonolysis of spirangien A, and for 1,3‐diene 5, obtained by cross‐metathesis with ethylene. X‐ray crystal structure analysis of 5 confirmed its structure and unambiguously provided the complete relative stereochemistry of all twelve stereocenters. The 1,3‐diene derivative 5 still shows strong cytotoxic activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Facile Access to Isotopically Labelled Valylleucyl Anilides as Biomarkers for the Quantification of Hemoglobin Adducts to Toxic Electrophiles
Authors: Belov Vladimir N. , Müller Michael , Ignatenko Oleg , Hallier Ernst , de Meijere Armin
Published: October 2005

An easy and efficient synthesis of valylleucyl anilide (HValLeuNHPh) and labelled HVal(13C5,15N)LeuNHPh has been developed. Derivatization of these substances with oxirane, acrylonitrile, epichlorohydrin, glyceraldehyde and other aldehydes gives a series of reference substances and internal standards for the quantitative evaluation of human exposure to toxic electrophiles by quantitative determination of their hemoglobin adducts. Coupling of N‐Z‐N‐Me‐Val(13C5,15N)OH with HLeuNHPh followed by hydrogenolysis affords N–Me–Val(13C5,15N)LeuNHPh for quantification of the exposure to methylating agents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Efficient Synthesis of 1,2,3‐Triazole‐Fused Bicyclic Compounds from Aldoses
Authors: Dolhem Franck , Al Tahli Fathia , Lièvre Catherine , Demailly Gilles
Published: October 2005

We would like to report an expedient synthesis of 1,2,3‐triazole‐fused bicyclic compounds starting from naturally occurring carbohydrates. These imino sugars were prepared in four steps from glyco‐ynitols, readily available from monosaccharides. The title compounds were prepared by intramolecular 1,3‐dipolar cycloaddition of azidoalkynes in a one‐pot substitution/thermal cyclization procedure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Reaction kinetics for the degradation of phenol and chlorinated phenols using Fenton's reagent
Authors: De Asim K. , Dutta Binay K. , Bhattacharjee Sekhar
Published: October 2005

Fenton's reaction is an advanced treatment technology often used for the removal of hazardous and refractory organic compounds from industrial wastewaters. It can effectively be used to degrade phenol and chlorophenols. The initial contaminant concentrations as well as the concentration of hydrogen peroxide and ferrous ions in aqueous solution have a significant effect on the effective degradation of contaminants. For a particular concentration of initial substrate in solution there should be an optimum level of ferrous ion concentration in the reaction medium.

Based on experimental observations, a probable mechanism for Fenton's degradation kinetics has been proposed and a rate equation developed. From the rate expression, OH· radical reaction rate constants for the degradation of three compounds—phenol and o‐ and p‐chlorophenols—in Fenton reaction were calculated to have values of 2.53 × 107, 2.38 × 107, and 2.45 × 107 m3 mol−1 s−1, respectively. © 2005 American Institute of Chemical Engineers Environ Prog, 2005
Drug entrapment in silica microspheres through a single step sol–gel process and in vitro release behavior
Authors: Yilmaz Elvan , Bengisu Murat
Published: October 2005

A single step sol–gel process was used to precipitate silica microspheres containing ibuprofen or naproxen for controlled drug delivery applications. The drug release behavior from these systems was analyzed in vitro. Pure ibuprofen and naproxen exhibited linear release with time, while sol–gel silica entrapped drugs were released with a logarithmic time dependence starting with an initial burst effect followed by a gradual decrease. Microscopic analysis combined with gravimety and infrared spectroscopy indicated that some of the drug is entrapped as large crystals attached to silica microspheres while the rest is encapsulated inside the microspheres. Drug‐loaded silica microspheres with no open porosity and with a narrow particle size distribution were obtained. Both erosion of the microspheres and diffusion through them contributed to drug release. Sol–gel precipitation of silica microspheres is a promising method for drug entrapment and controlled release. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Scalable molecular dynamics with NAMD
Authors: Phillips James C. , Braun Rosemary , Wang Wei , Gumbart James , Tajkhorshid Emad , Villa Elizabeth , Chipot Christophe , Skeel Robert D. , Kalé Laxmikant , Schulten Klaus
Published: October 2005

NAMD is a parallel molecular dynamics code designed for high‐performance simulation of large biomolecular systems. NAMD scales to hundreds of processors on high‐end parallel platforms, as well as tens of processors on low‐cost commodity clusters, and also runs on individual desktop and laptop computers. NAMD works with AMBER and CHARMM potential functions, parameters, and file formats. This article, directed to novices as well as experts, first introduces concepts and methods used in the NAMD program, describing the classical molecular dynamics force field, equations of motion, and integration methods along with the efficient electrostatics evaluation algorithms employed and temperature and pressure controls used. Features for steering the simulation across barriers and for calculating both alchemical and conformational free energy differences are presented. The motivations for and a roadmap to the internal design of NAMD, implemented in C++ and based on Charm++ parallel objects, are outlined. The factors affecting the serial and parallel performance of a simulation are discussed. Finally, typical NAMD use is illustrated with representative applications to a small, a medium, and a large biomolecular system, highlighting particular features of NAMD, for example, the Tcl scripting language. The article also provides a list of the key features of NAMD and discusses the benefits of combining NAMD with the molecular graphics/sequence analysis software VMD and the grid computing/collaboratory software BioCoRE. NAMD is distributed free of charge with source code atwww.ks.uiuc.edu. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1781–1802, 2005
Increased HEXIM1 expression during erythroleukemia and neuroblastoma cell differentiation
Authors: Turano Mimmo , Napolitano Giuliana , Dulac Cyprien , Majello Barbara , Bensaude Olivier , Lania Luigi
Published: October 2005

The HEXIM1 protein, in association with 7SK snRNA, binds and inhibits the kinase activity of P‐TEFb (CDK9/cyclin T). P‐TEFb activity is crucial for efficient transcription elongation of viral and cellular genes. HEXIM1 was originally isolated as a protein up‐regulated by hexamethylene bisacetamide (HMBA), a prototypical inducer of differentiation. To determine the causative role of HEXIM1 during cell differentiation we analyzed the biochemical and functional consequences of HEXIM1 protein levels in several in vitro differentiation systems. We found that HEXIM1 mRNA and protein levels are up‐regulated during differentiation of murine erythroleukemia cells upon treatment with HMBA or DMSO. Stimulation of HEXIM1 is not restricted to hematopoietic cells, as induction of phenotypic differentiation of neuroblastoma cells by retinoic acid results in up‐regulation of HEXIM1. Moreover, ectopic expression of HEXIM1 causes growth inhibition and promotes neuronal differentiation. These findings highlight a crucial role of HEXIM1 protein during cell differentiation. © 2005 Wiley‐Liss, Inc.
p16INK4A and CDH13 hypermethylation in tumor and serum of non‐small cell lung cancer patients
Authors: Ulivi Paola , Zoli Wainer , Calistri Daniele , Fabbri Francesco , Tesei Anna , Rosetti Marco , Mengozzi Marta , Amadori Dino
Published: October 2005

Aberrant promoter hypermethylation of several known or putative tumor suppressor genes occurs frequently during the etiopathogenesis of lung cancer and is a promising tool for cancer detection. In the present study, promoter hypermethylation of p16INK4A and CDH13 genes was investigated in tumor tissue and in matched serum from 61 patients with histologically confirmed non‐small cell lung cancer. Using a fluorescence‐based method of methylation‐specific PCR (F‐MSP), methylation of p16INK4A and CDH13 was detected in 79% and 66% of tumors, respectively, and was not significantly related to conventional clinicopathological characteristics of patients or tumors. Methylation of both genes was observed in 52% of tumors and of at least one gene in 92% of lesions. In matched serum, hypermethylation of p16INK4A and CDH13 was observed in 26% and 23% of patients, respectively, but as they were not associated, the methylation of at least one gene was detected in 39% of patients. In conclusion, the frequency of p16INK4A or CDH13 hypermethylation in patient serum, together with evidence of their early occurrence in lung cancerogenesis and the total lack of methylation in serum from healthy individuals, offer a promising tool for non invasive early detection of lung cancer. © 2005 Wiley‐Liss, Inc.
Na+/K+/Cl− cotransporter activates MAP‐kinase cascade downstream to protein kinase C, and upstream to MEK
Authors: Panet Rivka , Eliash Michal , Atlan Henri
Published: October 2005

In this study, we demonstrated that the specific inhibitors of the Na+/K+/Cl− cotransporter (NKCC1), bumetanide and furosemide, inhibited extracellular regulated kinase (ERK) phosphorylation in Balb/c 3T3 fibroblasts, stimulated with a variety of mitogens. In addition to fibroblast growth factor (FGF) shown before, the various mitogens tested in the present study (endothelial growth factor (EGF), platelet‐derived growth factor (PDGF), insulin, thrombin, and the phorbol ester, 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA)). Enter, the Ras/Raf/MEK/ERK cascade via different growth factors receptors and through one of the two main routes. The results of the present study provide evidence that have led us to conclude that the target protein which is controlled by the Na+/K+/Cl− cotransporter, is downstream of tyrosine kinase receptors, as well as of the G‐protein‐coupled receptor (GPCR). Several additional lines of evidence supported the above conclusion: (i) furosemide inhibits phosphorylation of MAPK kinase (MEK) induced by receptor tyrosine kinase (RTK) ligands, such as PDGF, FGF, and EGF. (ii) Furosemide also inhibited ERK phosphorylation, induced by thrombin, a GPCR. (iii) Furosemide inhibited MEK and ERK phosphorylation even when ERK phosphorylation was induced by direct activation of protein kinase C (PKC) by TPA, which bypasses early steps of the mitogenic cascade. In addition, we found that furosemide did not affect PKC phosphorylation induced directly by TPA. Taken together, the results of the present study indicate that the signal transduction protein, controlled by the Na+/K+/Cl− cotransporter, must be downstream of the PKC, and at/or upstream to MEK in the Ras/Raf/MEK/ERK cascade. © 2005 Wiley‐Liss, Inc.