bluuebunny/crossref_metadata_2025_split huggingface dataset:
4‐Methyl‐ and 4‐(Halophenyl)pyrimidinium (4‐Halobenzoyl)methylides. Correlation of Structure, Stability, Reactivity, and Biological Activity
Authors: Moldoveanu Costel C. , Mangalagiu Ionel I. 
Published: October 2005

AbstractFor the first time in the cycloimminium ylide series, we present a theoretical and experimental study concerning the correlation between structure, stability, reactivity, and biological activity of 4‐(R)‐pyrimidinium (4‐halobenzoyl)methylides (R = Me and 4‐chlorophenyl; hal = X = F, Cl, Br, I; see 5 and 6 in Scheme 1). The 4‐methylpyrimidinium (4‐halobenzoyl)methylides 5 are relatively stable compounds, while the (4‐chlorophenyl)pyrimidinium (4‐halobenzoyl)methylides 6 are more unstable. Their stability varies with the nature of the substituents at the ylide carbanion and pyrimidinium cation moieties as confirmed by quantum‐chemical calculations. The latter also disclose the possibility to use pyrimidinium ylides as nucleophilic reagents as well as 1,3‐dipoles in reactions with appropriate reagents. The experimental data obtained confirm the calculations concerning the nucleophilicity and reactivity of the ylides 5 and 6. Moreover, the influence of microwave irradiation on the synthesis of the pyrimidinium salts 3 and 4 from pyrimidine and an organic halide is studied and reveals a remarkable reaction‐rate increase under microwave irradiation as compared to classical conditions; this allows the general and facile synthesis of the salts 3 and 4 (Scheme 1, Table 1). The in vitro biological activity of the newly obtained 4‐methylpyrimidine compounds is also tested. Some of them exhibit a remarkable activity against different microorganisms (germs and fungi) which allows to establish structure–activity correlations.
Diterpenes and Disulfides from the Marine Mangrove Plant Bruguiera sexangula var. rhynchopetala
Authors: Bao Shuyun , Deng Zhiwei , Fu Hongzheng , Proksch Peter , Lin Wenhan 
Published: October 2005

AbstractPhytochemical investigation of the stems of Bruguiera sexangula var. rhynchopetala resulted in the isolation and characterization of four new and seven known secondary metabolites. The new compounds were spectroscopically identified as 17‐hydroxy‐16‐oxobeyer‐9(11)‐en‐19‐al (1), 16,17‐dihydroxy‐19‐nor‐ent‐kaur‐9(11)‐en‐3‐one (2), (16R)‐13,17‐epoxy‐16‐hydroxy‐ent‐kaur‐9(11)‐en‐19‐al (3), and (−)‐3,4‐dihydro‐3‐hydroxy‐7‐methoxy‐2H‐1,5‐benzodithiepine‐6,9‐dione (10). The configurations of the known compounds brugierol (11) and isobrugierol (12) were re‐investigated. Compounds 11 and 12, together with 2,6‐dimethoxy‐1,4‐benzoquinone (13), are proposed to be degradation products of the novel, unusual disulfide 10 (Scheme).
Synthesis of Eburnamine, Isoeburnamine, and Eburnamonine via a Spirocyclic Intermediate
Authors: Ho Tse‐Lok , Chen Chun‐Kuei 
Published: October 2005

AbstractRacemic eburnamonine (1) was synthesized via 6, an intermediate possessing local symmetry. Cleavage of the cyclopentene subunit led to pentacyclic aldehydes 8a/8b which on subsequent borohydride and Wolff–Kishner reductions gave 12. The final steps included a RuCl3‐catalyzed periodate oxidation and pyridinium chlorochromate (PCC) oxidation. The penultimate intermediates were racemic eburnamine (2) and racemic isoeburnamine (3).
Synthesis of Some New 1,2,4‐Triazole Derivatives by Mitsunobu Chemistry
Authors: Alizadeh Abdolali 
Published: October 2005

AbstractThe reactive 1 : 1 intermediate produced in the reaction between triphenylphosphine and diisopropyl azodicarboxylate has been trapped by isocyanates or isothiocyanates to yield 1,2,4‐triazole derivatives 2 (Scheme 1). The structures of the highly functionalized compounds 2 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, EI‐MS) and by elemental analyses. A mechanism for this type of cyclization is proposed (Scheme 2).
Conformations of the Nine‐Membered Ring in the B‐Nor‐5,10‐secosteroids. X‐Ray and NMR Analysis
Authors: Bjelaković Mira S. , Krstić Natalija M. , Tinant Bernard , Kalvoda Jaroslav , Csanadi Janos , Pavlović Vladimir D. 
Published: October 2005

AbstractThe conformations of (Z)‐ and (E)‐5‐oxo‐B‐nor‐5,10‐secocholest‐1(10)‐en‐3β‐yl acetates (2 and 3, resp.) were examined by a combination of X‐ray crystallographic analysis and NMR spectroscopy, with emphasis on the geometry of the cyclononenone moiety. The 1H‐ and 13C‐NMR spectra showed that the unsaturated nine‐membered ring of (E)‐isomer 3 in C6D6 and (D6)acetone solution exists in a sole conformation of type B1, which is similar to its solid‐state conformation. The (Z)‐isomer 2 in C6D6, CDCl3, and (D6)acetone solution, however, exists in two conformational forms of different families, with different orientation of the carbonyl group, the predominant form (85%) corresponding to the conformation of type A1 and the minor (15%) to the conformation A2 present also in the crystalline state. In this solid‐state conformations of the nine‐membered ring of both compounds, the 19‐Me and 5‐oxo groups are ‘β’‐oriented. The NMR analysis suggests that the nine‐membered ring of 4 has a conformation of type C1 in CDCl3 solution.
Molecular targets in melanoma: Strategies and challenges for diagnosis and therapy
Authors: Herlyn Meenhard 
Published: October 2005

AbstractIn coming years, we expect rapid advances in cutaneous melanoma diagnosis and therapy, because of the incorporation of new technologies into experimental and clinical research. Major discoveries in melanoma are often made by investigators outside the field, and the melanoma research community will need to develop a better means of incorporating these advances into their work, to capitalize on the promise they hold for patients. A far greater level of cooperation between labs and clinics will be to bring new technology‐based discoveries from bench‐to‐bedside and back. Metastatic melanoma should become a treatable disease in the next few years, because specific inhibitors are expected for most major targets. However, major challenges lie ahead in securing funding, building infrastructure and gaining expertise in new technologies. To meet these challenges, multidisciplinary collaborations will be required all the more. © 2005 Wiley‐Liss, Inc.
Poly‐ϵ‐caprolactone/hydroxyapatite composites for bone regeneration: In vitro characterization and human osteoblast response
Authors: Causa F. , Netti P. A. , Ambrosio L. , Ciapetti G. , Baldini N. , Pagani S. , Martini D. , Giunti A. 
Published: October 2005

AbstractPolycaprolactone (PCL), a semicrystalline linear resorbable aliphatic polyester, is a good candidate as a scaffold for bone tissue engineering, due to its biocompatibility and biodegradability. However, the poor mechanical properties of PCL impair its use as scaffold for hard tissue regeneration, unless mechanical reinforcement is provided. To enhance mechanical properties and promote osteoconductivity, hydroxyapatite (HA) particles were added to the PCL matrix: three PCL‐based composites with different volume ratio of HA (13%, 20%, and 32%) were studied. Mechanical properties and structure were analysed, along with biocompatibility and osteoconductivity. The addition of HA particles (in particular in the range of 20% and 32%) led to a significant improvement in mechanical performance (e.g., elastic modulus) of scaffold. Saos‐2 cells and osteoblasts from human trabecular bone (hOB) retrieved during total hip replacement surgery were seeded onto 3D PCL samples for 1–4 weeks. Following the assessment of cell viability, proliferation, morphology, and ALP release, HA‐loaded PCL was found to improve osteoconduction compared to the PCL alone. The results indicated that PCL represents a potential candidate as an efficient substrate for bone substitution through an accurate balance between structural/ mechanical properties of polymer and biological activities. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Preparation and swelling behavior of chitosan‐based superporous hydrogels for gastric retention application
Authors: Park Hyojin , Park Kinam , Kim Dukjoon 
Published: October 2005

AbstractChitosan and glycol chitosan hydrogels were prepared, and their swelling behaviors in acidic solution were studied to investigate their application for gastric retention device. The optimum preparation condition of superporous hydrogels was obtained from the gelation and blowing kinetics measured at varying acidic conditions. Both the swelling rate and swelling ratio of glycol chitosan hydrogels were higher than those of chitosan hydrogels. Swelling behaviors were significantly affected by not only foaming/drying methods but also crosslinking density, as the sizes and structures of pores generated were highly dependent on those preparation conditions. The prepared superporous hydrogels were highly sensitive to pH of swelling media, and showed reversible swelling and de‐swelling behaviors maintaining their mechanical stability. The degradation kinetics in simulated gastric fluid was also studied. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Synthesis and characterization of poly‐α,β‐[N‐(2‐hydroxyethyl)‐L‐aspartamide]‐g‐poly(L‐lactide) biodegradable copolymers as drug carriers
Authors: Peng Tao , Cheng Si‐Xue , Zhuo Ren‐Xi 
Published: October 2005

AbstractA series of biodegradable amphiphilic graft polymers were successfully synthesized by grafting poly(L‐lactide) (PLLA) sequences onto a water‐soluble polymer poly‐α,β‐[N‐(2‐hydroxyethyl)‐L‐aspartamide] (PHEA) backbone. We established the feasibility of preparing these novel graft polymers by the ring‐opening polymerization initiated by the macroinitiator PHEA bearing hydroxyl groups without adding any catalyst. The successful grafting of PLLA sequences onto the PHEA backbone was verified by combined size exclusion chromatography (SEC) and multiangle laser light scattering (MALLS) analysis. The chemical structures of graft polymers were characterized by FTIR and 1H NMR. The critical micelle concentration (CMC) of the graft polymer was determined by fluorescence probe technique using pyrene. By controlling the feed ratio of the macroinitiator to the monomer, graft polymers with different branch lengths can be obtained. Using the 3‐(4,5 dimethylthiozol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide (MTT) assay, the graft copolymer has been proved to have low cytotoxicity. Based on the amphiphilicity of the graft copolymers, nanoparticular drug delivery systems were prepared by the direct dissolution method and the dialysis method. The anticancer drug Tegafur was encapsulated into polymeric nanoparticles, and in vitro drug release behavior was investigated. Transmission electron microscopy (TEM) images demonstrate that these nanoparticles are regularly spherical in shape. The particle size and distribution of the nanoparticles were measured. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Influence of salivary organic substances on the discoloration of esthetic dental materials—A review
Authors: Lee Yong‐Keun , Powers John M. 
Published: October 2005

AbstractThe objective of this article was to review the articles on the interaction of salivary organic substances with resin‐based dental materials and on the interaction of these organic substances with exogenous chemical agents, which results in discoloration. Original scientific articles or reviews on the saliva, acquired pellicle, and the interaction with pellicle and chemical agents related to dental resin‐based materials were reviewed. Salivary esterases can increase or decrease the internal and external discoloration. The formation of acquired pellicle on the surface of a material varies by the properties of material, and the pellicle interacts with denaturation agents, such as tannin and chlorhexidine, to form stains and also adsorbs staining substances. Therefore, for the quality and longevity of restorations, protocols for the evaluation of the influence of organic substances on the extrinsic staining of restorative materials should be included in the evaluation of aesthetic restorative materials. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Manufacturing, mechanical characterization, and in vitro performance of bioactive glass 13–93 fibers
Authors: Pirhonen E. , Niiranen H. , Niemelä T. , Brink M. , Törmälä P. 
Published: October 2005

AbstractFibers were manufactured from the bioactive glass 13–93 by melt spinning. The fibers were further characterized by measuring their tensile and flexural strength, and their in vitro performance was characterized by immersing them in simulated body fluid, which analyzed changes in their mass, their flexural strength, and surface reactions. The strength of glass fibers is highly dependent on fiber diameter, test method, and possible surface flaws, for example, cracks due to abrasion. In this study, the thinnest fibers (diameter between 24 and 33 μm) possessed the highest average tensile strength of 861 MPa. The flexural strength was initially 1353.5 MPa and it remained at that level for 2 weeks. The Weibull modulus for both tensile and flexural strength values was initially about 2.1. The flexural strength started to decrease and was only ∼20% of the initial strength after 5 weeks. During the weeks 5–40, only a slight decrease was detected. The flexural modulus decreased steadily from 68 to 40 GPa during this period. The weight of the samples initially decreased due to leaching of ions and further started to increase due to precipitation of calcium phosphate on the fiber surfaces. The mass change of the bioactive glass fibers was dependent on the surface area rather than initial weight of the sample. The compositional analysis of the fiber surface after 24 h and 5 weeks immersion did confirm the initial leaching of ions and later the precipitation of a calcium phosphate layer on the bioactive glass 13–93 fiber surface in vitro. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Cranial anatomy of the spade‐headed amphisbaenian Diplometopon zarudnyi (Squamata, amphisbaenia) based on high‐resolution X‐ray computed tomography
Authors: Maisano Jessica Anderson , Kearney Maureen , Rowe Timothy 
Published: October 2005

AbstractThe skull of the trogonophid amphisbaenian Diplometopon zarudnyi is described from high‐resolution X‐ray computed tomographic (HRXCT) imagery of a whole museum specimen preserved in ETOH. The skull was digitally resliced and disarticulated into individual elements, producing novel visualizations that allow detailed morphological analysis of its three‐dimensionally complex structure. The prefrontal and jugal are absent in Diplometopon. The septomaxilla is present but hidden entirely from superficial view. In contrast to previous studies, we recognize a splenial fused to the compound bone of the mandible and a squamosal fused to the otic–occipital complex. Comparison of Diplometopon to the two other amphisbaenians previously described in comparable detail, Rhineura hatcherii and Amphisbaena alba, reveals a mosaic of cranial similarities and differences. Both Diplometopon and Rhineura exhibit a craniofacial angulation and expanded rostral blade related to use of the head as a digging tool, but the detailed architecture of these features is quite different. Additionally, whereas the snout of Rhineura exhibits a high degree of sculpturing and sensory innervation, this is not the case in Diplometopon. Unlike in Rhineura and Amphisbaena, the cranial elements of Diplometopon do not exhibit an extensive degree of overlap or complex interlocking sutures; instead, most of the cranial elements lie in loose apposition to each other. The degree to which this mosaic of features reflects functional demands, shared ancestry, and/or convergence is unclear in the absence of a stable hypothesis of amphisbaenian phylogeny. J. Morphol. © 2005 Wiley‐Liss, Inc.
Desmosomes in uterine epithelial cells decrease at the time of implantation: An ultrastructural and morphometric study
Authors: Preston Amanda M. , Lindsay Laura A. , Murphy Christopher R. 
Published: October 2005

AbstractDisplacement of uterine epithelial cells is an important aspect of implantation in the rat and other species, allowing invasion of the blastocyst into the endometrial stroma. Desmosomes, which are part of the lateral junctional complex, function in cell‐to‐cell adhesion, and are therefore likely to be involved in displacement of uterine epithelial cells at the time of implantation. This study used transmission electron microscopy to study rat uterine epithelial cells during the peri‐implantation period to investigate the change in the number of structural desmosomes along the lateral plasma membrane of uterine epithelial cells. We found a significant decrease in the number of desmosomes along the entire lateral plasma membrane as pregnancy progressed. Furthermore, there were also significant decreases in the number of desmosomes on the apical portion of the lateral plasma membrane between all days of pregnancy examined. In addition, on day 6 of pregnancy, the time of attachment, desmosomes were larger and seen as “giant desmosomes.” For the first time, this study has shown that there is a significant reduction in cell height and actual number of ultrastructurally observable desmosomes at the time of implantation in the rat. It is proposed that this reduction in desmosome number leads to a decrease in lateral adhesion between uterine epithelial cells at the time of implantation, and hence is involved in the loss of uterine epithelial cells to facilitate blastocyst invasion. J. Morphol. © 2005 Wiley‐Liss, Inc.
Gas‐phase tautomers of protonated 1‐methylcytosine. Preparation, energetics, and dissociation mechanisms
Authors: Yao Chunxiang , Cuadrado‐Peinado Maria L. , Polášek Miroslav , Tureček František 
Published: October 2005

AbstractTautomers of 1‐methylcytosine that are protonated at N‐3 (1+) and C‐5 (2+) have been specifically synthesized in the gas phase and characterized by tandem mass spectrometry and quantum chemical calculations. Ion 1+ is the most stable tautomer in aqueous and methanol solution and is likely to be formed by electrospray ionization of 1‐methylcytosine and transferred in the gas phase. Gas‐phase protonation of 1‐methylcytosine produces a mixture of 1+ and the O‐2‐protonated tautomer (3+), which are nearly isoenergetic. Dissociative ionization of 6‐ethyl‐5,6‐dihydro‐1‐methylcytosine selectively forms isomer 2+. Upon collisional activation, ions 1+ and 3+ dissociate by loss of ammonia and [C,H,N,O], whose mechanisms have been established by deuterium labeling and ab initio calculations. The main dissociations of 2+ following collisional activation are losses of CH2CNH and HNCO. The mechanisms of these dissociations have been elucidated by deuterium labeling and theoretical calculations. Copyright © 2005 John Wiley & Sons, Ltd.
Ion/molecule reactions in a miniature RIT mass spectrometer
Authors: Chen Huanwen , Xu Ruifeng , Chen Hao , Cooks R. Graham , Ouyang Zheng 
Published: October 2005

AbstractIon/molecule reactions were explored in a newly developed miniature mass spectrometer fitted with a rectilinear ion trap (RIT) mass analyzer. The tandem mass spectrometry performance of this instrument is demonstrated using collision induced dissociation (CID) and ion/molecule reactions. The latter includes Eberlin transacetalization reactions and electrophilic additions. Selective detection of the chemical warfare simulant dimethyl methyl phosphonate (DMMP) was achieved through selective Eberlin reactions of its characteristic phosphonium fragment ion CH3OP+(O)CH3 (m/z 93), with 1,4‐dioxane or 1,3‐dioxolane. Efficient adduct formation as a result of electrophilic attack by the phosphonium ion on various nucleophilic reagents, including 1,1,3,3‐tetramethyl urea, methanesulfonic acid methyl ester, dimethyl sulfoxide and methyl salicylate, was also observed using the RIT device. The product ions of these reactions were analyzed using CID and the characteristic fragmentation patterns of the ionic addition products were recorded using multiple‐stage experiments in the miniature RIT instrument. This study clearly demonstrates that a small, home‐built, miniature RIT mass spectrometer can be used to perform analytically useful ion/molecule reactions and also that instruments like this have the potential to provide a portable platform for in situ detection of organophosphorus esters and related compounds with high specificity using tandem mass spectrometry. Copyright © 2005 John Wiley & Sons, Ltd.
CYTE‐I‐HD: Phase I dose finding and tolerability study of cysteamine (Cystagon) in Huntington's disease
Authors: Dubinsky Richard , Gray Carolyn 
Published: October 2005

AbstractCystamine, an inhibitor of transglutaminases, slows progression of Huntington's disease in the murine model by approximately 20%. Cysteamine, the dimer of cystamine, is an orphan drug approved for the treatment of nephropathic cystinosis and has a similar benefit in the murine model but with a narrower therapeutic window. In a single‐center open‐label study, we determined the maximum tolerable dose (MTD) and side effects of cysteamine in people with Huntington's disease. Cysteamine was started at a dose of 10 mg/kg per day, divided into four doses, and increased by 10 mg/kg per day weekly until the development of intolerable side effects or a maximum dose of 70 mg/kg per day. Of the 9 subjects, 1 had an MTD of 10 mg/kg per day, 1 had an MTD of 20 mg/kg per day, the maximum dose was 30 mg/kg per day for 2, 40 mg/kg per day for 2, and 50 mg/kg per day for 3. Dose‐limiting side effects were motoric impairment in 5 and nausea in 4. The dose found tolerable by 8 of the subjects was 20 mg/kg per day. All had a noticeable hydrogen sulfide odor at doses of 40 mg/kg per day or higher. We conclude that, at a dose of 20 mg/kg per day, cysteamine was tolerable in people with Huntington's disease. Nausea and motoric impairment were the dose‐limiting side effects. © 2005 Movement Disorder Society
Cardiac conduction alterations in a French family with amyloidosis of the finnish type with the p.Asp187Tyr mutation in the GSN gene
Authors: Chastan Nathalie , Baert‐Desurmont Stéphanie , Saugier‐Veber Pascale , Dérumeaux Geneviève , Cabot Annick , Frébourg Thierry , Hannequin Didier 
Published: October 2005

AbstractFamilial amyloidosis of the Finnish type (FAF) is a rare autosomal‐dominant disorder caused by the accumulation of a 71–amino acid amyloidogenic fragment of mutant gelsolin, an actin‐modulating protein. The main symptoms include corneal lattice dystrophy, progressive cranial and peripheral neuropathy, and skin changes. To date, only two mutations in the GSN gene have been described: the p.Asp187Asn mutation in most patients and the p.Asp187Tyr mutation in a Danish and Czech family. We report on the third family with the p.Asp187Tyr mutation and the first French FAF family. Severe cardiac conduction alterations in three patients were mainly caused by cardiac sympathetic denervation. These findings demonstrate the cardiological involvement of the FAF phenotype and suggest that cardiological follow‐up is required in FAF patients. Muscle Nerve, 2006