bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of combined DC and AC magnetic fields on germination of hornwort seeds
Authors: Kobayashi Masanori , Soda Naoya , Miyo Takuya , Ueda Yoshiro 
Published: September 2004

AbstractSeeds of hornwort (Cryptotaenia japonica Hassk) were exposed to sinusoidally time‐varying extremely low frequency (ELF) magnetic fields (AC fields) in combination with the local geomagnetic field (DC field). Exposure lasted 24 h/day for 16 days. Three directions of the AC magnetic fields were considered; the vertical (magnetic flux density $\vec B_{ACV}$), the directions parallel ($\vec B_{AC||}$), and perpendicular ($\vec B_{AC \bot }$) to the direction of total geomagnetic field (magnetic flux density $\vec B_G$) in the geomagnetic plane (GP). Controls consisted of seeds exposed to zero AC magnetic fields in combination with the DC magnetic field. The $\vec B_{ACV}$ in combination with $\vec B_G$ effectively promoted the germination of hornwort seeds when applied at 750 μT (RMS) at 7 Hz or 500 μT (RMS) at 14 Hz from among the cases of individual frequencies f = 3.5, 7.0, 10.5, 14.0 Hz at 500 and 750 μT. The $\vec B_{AC||}$ promoted the germination of hornwort seeds more effectively than the $\vec B_{AC \bot }$ in combination with $\vec B_G$ when 500 and 750 μT at 7 Hz were applied. Bioelectromagnetics 25:552–559, 2004. © 2004 Wiley‐Liss, Inc.
Guidance for exposure design of human studies addressing health risk evaluations of mobile phones
Authors: Kuster Niels , Schuderer Jürgen , Christ Andreas , Futter Peter , Ebert Sven 
Published: September 2004

AbstractConflicting results have recently emerged from human provocation studies that addressed the possible health hazards of radio frequency (RF) field exposure from mobile phones. Different findings may have resulted from exposures that are poorly defined and difficult to compare. The aim of this study was to develop guidelines to facilitate the development of exposure systems for human volunteer studies which lead to reproducible results and which provide maximum relevance with respect to the assessment of the safety of mobile technology. The most important exposure parameters are discussed such as the signal, field distribution, and field strength, as well as the minimum requirements for the setup and dosimetry. Bioelectromagnetics 25:524–529, 2004. © 2004 Wiley‐Liss, Inc.
Arteriovenous glomeruli of the human spinal cord and their possible functional implications
Authors: Parke Wesley W. 
Published: September 2004

AbstractA previous investigation of the radiculomedullary vascular distribution of the human spinal cord showed an immediate filling of the peripheral spinal veins during arterial injections. Because the perfused medium, a mixture of latex and India ink, had a sufficient viscosity to preclude capillary passage, an extensive system of arteriovenous anastomoses (AVA) was indicated. The injection of five additional anatomic cadaver spinal cords was undertaken to specifically determine the intraparenchymal position and structure of these AVA. It was found that only cleared and transilluminated longitudinal parasagittal sections adequately showed that the AVA were formed by an extensive array of intricately coiled arteriovenous glomeruli (AVG) that could pass substantial amounts of blood from third order arterial branches to equivalently sized veins, bypassing the capillary bed. The epithelioid structure of these AVG channel walls, coupled with their highly innervated adventitial tissue indicated a possible functional relationship to similar structures found in the ends (digital pads) of mammalian extremities. Stained serial sections of injected cords showed the vascular relations with nerve fibers derived from the intraspinal parenchyma as well as a possible extraparenchymal autonomic fiber source. The numbers and extent of these AVG complexes suggested they might be involved in the remarkable autoregulation of spinal cord blood flow (SCBF) that is impervious to middle range changes in systemic blood pressure. Future research may more accurately determine the functional role of these previously unreported human spinal AVG, particularly in their possible relation to SCBF autoregulation in normal and injured spines. Clin. Anat. 17:558–563, 2004. © 2004 Wiley‐Liss, Inc.
Regioselective Samarium Diiodide Induced Couplings of Carbonyl Compounds with 1,3‐Diphenylallene and Alkoxyallenes: A New Route to 4‐Hydroxy‐1‐enol Ethers
Authors: Hölemann Alexandra , Reißig Hans‐Ulrich 
Published: September 2004

AbstractSince its introduction into synthetic organic chemistry, samarium diiodide has found broad application in a variety of synthetically important transformations. Herein, we describe the first successful intermolecular additions of samarium ketyls to typical allenes such as 1,3‐diphenylallene (7), methoxyallene (12) and benzyloxyallene (25). Reaction of different samarium ketyls with 1,3‐diphenylallene (7) occurred exclusively at the central carbon atom of the allene to afford products 9 in moderate to good yields. In contrast, reductive coupling of cyclic ketones to methoxyallene (12) regioselectively provided 4‐hydroxy‐1‐enol ethers 13, which derive from addition to the terminal allene carbon atom of 12, in moderate to good yields. Whereas the E/Z selectivity with respect to the enol ether double bond is low, excellent diastereoselectivity has been observed in certain cases with regard to the ring configuration (e.g. compound 13 b). Studies with deuterated tetrahydrofuran and alcohol were performed to gain information about the reaction mechanism of this coupling process, which involves alkenyl radicals. The couplings of samarium ketyls derived from acyclic ketones and aldehydes gave lower yields, and in several cases cyclopentanols 20 are formed as byproducts. Branched acyclic ketones and conformationally more flexible cyclic ketones such as cycloheptanone led to a relatively high amount of cyclopentanol derivatives 20, whose formation involves an intramolecular hydrogen atom transfer through a geometrically favoured six‐membered transition state followed by a cyclization step. The samarium diiodide mediated addition of 8 b to benzyloxyallene (25) afforded the expected enol ethers 26, albeit in only low yield. Additionally, spirocyclic compounds 27 and 28 were obtained, which are formed by a cascade reaction involving an addition/cyclization sequence. In the novel coupling process described here methoxyallene (12) serves as an equivalent of acrolein. The 1,4‐dioxygenated products obtained contain a masked aldehyde functionality and are therefore valuable building blocks in organic synthesis.
Xenopus paraxis homologue shows novel domains of expression
Authors: Carpio Ronald , Honoré Stella Maris , Araya Claudio , Mayor Roberto 
Published: September 2004

AbstractThe paraxis gene encodes a basic helix‐loop‐helix transcription factor that is expressed in paraxial mesoderm and whose mutant displays an inability to form epithelial somites. Here, the molecular characterization of Xenopus paraxis is reported. paraxis is expressed in the paraxial mesoderm and somites but is down‐regulated during muscle differentiation. In addition to its paraxial mesodermal expression, described in other organisms, two novel expression domains of paraxis were found: the neural tube and the head mesoderm. paraxis expression in the neural tube was compared with the expression of the neural markers Xash and Xiro1, and we concluded that paraxis is expressed in a broad band in the prospective sulcus limitans of the neural tube. Developmental Dynamics 231:609–613, 2004. © 2004 Wiley‐Liss, Inc.
Pacinian corpuscle development involves multiple Trk signaling pathways
Authors: Šedý J. , Szeder V. , Walro J.M. , Ren Z.G. , Naňka O. , Tessarollo L. , Sieber‐Blum M. , Grim M. , Kucera J. 
Published: September 2004

AbstractThe development of crural Pacinian corpuscles was explored in neonatal mutant mice lacking nerve growth factor (NGF), brain‐derived neurotrophic factor (BDNF), neurotrophin‐3 (NT3) or neurotrophin‐4 (NT4), or their cognate Trk receptors. Deficits of the corpuscles and their afferents were greatest in NT3, less in BDNF, and least in NT4 null mice. Deletion of NGF or p75NTR genes had little or no impact. No Pacinian corpuscles were present in NT3;BDNF and NT3;NT4 double or NT3;BDNF;NT4 triple null mice. Deficits were larger in NT3 than TrkC mutants and were comparable to deficits observed in TrkB or TrkA mutants. Afferents of all corpuscles coexpressed TrkA and TrkB receptors, and some afferents coexpressed all three Trk receptors. Our results suggest that multiple neurotrophins, in particular NT3, regulate the density of crural Pacinian corpuscles, most likely by regulating the survival of sensory neurons. In addition, NT3/TrkB and/or NT3/TrkA signaling plays a greater role than NT3/TrkC signaling in afferents to developing Pacinian corpuscles. Developmental Dynamics 231:551–563, 2004. © 2004 Wiley‐Liss, Inc.
Expression of mouse Foxi class genes in early craniofacial development
Authors: Ohyama Takahiro , Groves Andrew K. 
Published: September 2004

AbstractRecent models of craniofacial development suggest the existence of a common pan‐placodal domain lying next to the neural plate, from which all sensory placodes will arise. In support of this idea, several genes are expressed in the surface ectoderm of the head adjacent to the neural plate, before the appearance of genes in specific cranial placodes. In this study, we examine the expression patterns of the mouse Foxi class genes from embryonic day 6.5 to 10.5. Foxi2 is expressed throughout the cranial ectoderm adjacent to the neural plate from the 4‐somite stage, later becoming excluded from the otic placode. Foxi3 is expressed in a broad region of the pan‐placodal ectoderm adjacent to the neural plate from embryonic day (E) 6.75 to the first somite stage. Its expression becomes restricted to the ectoderm and the endoderm of the branchial pouches at E10.5. Foxi1 expression is first detected in the endolymphatic duct in the otic vesicle at E10.5. These results suggest that the mouse Foxi class genes may play important roles, both during cranial placode specification and in later development of individual cranial sensory structures and other organs derived from the cranial ectoderm. Developmental Dynamics 231:640–646, 2004. © 2004 Wiley‐Liss, Inc.
Salmonella typhimurium infection halts development of type 1 diabetes in NOD mice
Authors: Zaccone Paola , Raine Tim , Sidobre Stéphane , Kronenberg Mitchell , Mastroeni Pietro , Cooke Anne 
Published: September 2004

AbstractInfectious disease has been proposed as an environmental modifier of autoimmunity in both human populations and the NOD mouse. We found that infection of NOD mice with attenuated, but not killed, Salmonella typhimurium can reduce the incidence of type 1 diabetes (T1D), even if infection occurs after the development of a peri‐islet pancreatic infiltrate. Functional diabetogenic effector T cells are still present, as demonstrated by the initiation of diabetes in NOD‐scid recipients of transferred splenocytes. High levels of IFN‐γ are secreted by splenocytes of infected mice, but there is no evidence of involvement of IL‐10 in the protective effect of the infection. Finally, prolonged changes in cell subsets are observed in infected mice involving invariant Vα14Jα281 NKT and dendritic cells. These data reinforce the idea that prevention of T1D in the NOD mouse cannot be reduced to the simple Th1/Th2 paradigm and that different infections may involve different protective mechanisms.
A Homologous Series of Persubstituted Cyclodextrin Amino Acids: The Quest for Tubular Self‐Assembly
Authors: Kraus Tomáš , Buděšínský Miloš , Císařová Ivana , Závada Jiří 
Published: September 2004

AbstractThe synthesis, conformation and diverse self‐assembling patterns of the homologous series of chemically uniform per(6‐amino‐2‐O‐carboxymethyl‐6‐deoxy‐3‐O‐methyl)‐substituted α‐, β‐ and γ‐cyclodextrins 6a−6c are reported. Helical self‐assembly of the lowest homologue 6a gave rise to a three‐dimensional system of separate collinear channels. For the higher homologues 6b−6c, such a unique architecture is prohibited by unfavorable geometrical factors. A comparison has been made with the corresponding series of native and permethylated cyclodextrins, and the role played by hydrogen bonds in promoting tubular architectures has been assessed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synergetic Effects of Oxidative and Coordinative Promotors to Increase the Yield of a Twofold Pauson−Khand Reaction
Authors: Gleiter Rolf , Schulte J. Hilko , Werz Daniel B. 
Published: September 2004

AbstractFour medium‐sized cyclic diynes (7, 15−17), two cyclic dithiadiynes (18, 19) and two cyclic tetrathiadiynes (20, 21) were starting materials for Pauson−Khand reactions with ethylene and (octacarbonyl)dicobalt under four different conditions: A with 1 equivalent n‐butylmethyl sulfide (BMS), B with 7.5 equivalents dimethyl sulfoxide (DMSO), C with 7.5 equivalents DMSO and 1 equivalent BMS and D with 7.5 equivalents DMSO and 7.5 equivalents BMS as additives. In the cases of 7 and 15−17, the yields increased strongly by applying protocol C. For 18−21, no increase in the yields was found under conditions A−D. These differences are discussed and ascribed to intramolecular S−Co interactions in the cases of 18−21. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Synthesis of the Dimethyl Ester of Quino[4,4a,5,6‐efg]‐Annulated 7‐Demethyl‐8‐deethylmesoporphyrin and Three of Its Isomers with Unprecedented peri‐Condensed Quinoline Porphyrin Structures. Molecules with Outstanding Properties as Sensitizers for Photodynamic Therapy in the Far‐Red Region of the Visible Spectrum
Authors: van der Haas Richard N. S. , de Jong Robertus L. P. , Noushazar Maryam , Erkelens Kees , Smijs Threes G. M. , Liu Yan , Gast Peter , Schuitmaker Hans J. , Lugtenburg Johan 
Published: September 2004

AbstractThe mesoporphyrin dimethyl ester nickel complex has been formylated via the Vilsmeier method. The four possible mono meso‐formyl derivatives were isolated and characterized. Wadsworth−Emmons coupling with the anion of (diethylphosphono)acetonitrile converted these aldehydes into the four novel meso acrylonitriles. Brief treatment of these acrylonitrile systems in hot trichloroacetic acid resulted in the formation of four achiral porphyrin derivatives with unprecedented nickel complexes of quino‐fused porphyrins. Subsequent removal of the nickel gave four quino‐porphyrin free bases: quino[4,4a,5,6‐efg]‐annulated 7‐demethyl‐8‐deethylmesoporphyrin dimethyl ester 6a, 2′‐(methoxycarbonyl)quino[4,4a,5,6‐jkl]‐annulated 12‐demethyl‐13‐de[2′‐(methoxycarbonyl)ethyl]mesoporphyrin dimethyl ester 6b, 2′‐(methoxycarbonyl)quino[4,4a,5,6‐qrs]‐annulated 18‐demethyl‐17‐de(2′‐methoxycarbonylethyl)mesoporphyrin dimethyl ester 6c and quino[4,5,6,7‐abt]‐annulated 2‐demethyl‐3‐deethylmesoporphyrin dimethyl ester 6d. The structures of these systems were unambiguously determined via mass spectroscopy and a plethora of NMR techniques. In the same way, etioporphyrin and octaethylporphyrin were converted into the corresponding peri‐condensed quinoporphyrins as products, which shows that the formation of novel pericondensed quino‐porphyrins is a general reaction in the porphyrin series and will have a wide scope in this field. Also, a plausible reaction mechanism for the formation of the quinoporphyrin systems was derived. As a first test for the use of these systems as sensitizers in far‐red phototherapy, the quantum yield of singlet oxygen generation by 6a in toluene was studied. This quantum yield is 0.77, which is even higher than the singlet oxygen generation by sensitized meso‐tetraphenylporphyrin. Secondly, when Chinese Hamster ovary (CHO) cells were incubated in medium which contained up to 15 μg/ml of 6a, the survival rate of the cells in the dark is complete within experimental error, showing that under these conditions, 6a is not toxic to CHO cells. When CHO cells incubated in medium containing 6a in concentrations of 1 μg/ml and higher were treated with white light of intensity 30 mW/cm2 for 15 minutes, complete cell death was observed. Based on these facts, we expect that all four achiral systems will show very promising properties to form the basis of a photodynamic therapy in far‐red light. The fact that these systems are achiral is an additional bonus for medical applications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Enantioselective Synthesis and Circular Dichroism of Endocyclic Allenes
Authors: Zelder Claudia , Krause Norbert 
Published: September 2004

AbstractThe novel, enantiomerically enriched nine‐ and ten‐membered cyclic allenes (+)‐5a−c and (−)‐6a−c were synthesized by lipase‐catalyzed kinetic resolution of propargylic acetates 1/2 and subsequent anti‐stereoselective SN2′‐substitution with magnesium cuprates. The CD spectra of these allenes exhibit distinct features that are a function of the ring size and the alkyl substituent at the allene moiety. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Compared performances of different algorithms for estimating annual nutrient loads discharged by the eutrophic River Loire
Authors: Moatar Florentina , Meybeck Michel 
Published: September 2004

AbstractGood estimates of pollutant fluxes are required for Earth systems sciences and water quality management. The gradual accumulation of water quality data records over the past few decades has increased the value of these data for examining long‐term trends. On many major rivers, however, infrequent sampling of most pollutants makes flux estimates and their analysis difficult. This paper explores the performance of different methods for estimating nutrient fluxes. The objective is to assess the accuracy (bias) and precision (dispersion) of annual nutrient fluxes based on monthly sampling, which is the frequency with which 80% of French water quality surveys have been carried out since 1971. The study is based on a data set of nutrient concentrations surveyed at high frequency during a 5 year pilot study (1981–85) at the Orléans station in the middle reaches of the River Loire, France. The mean specific fluxes were 641 (nitrate‐N), 96 (total‐P) and 37 kg year−1 km−2 (orthophosphate‐P). For each year, the data set was then ‘resampled’ by randomly simulating 12 sampling dates. 100 simulated monthly samplings were generated, upon which seven estimation methods were tested. The evaluations indicate that, when concentrations of specific substances in large rivers exhibit seasonal variation, a simple method based on linear interpolation between samples taken at approximately monthly intervals is advocated. With the monthly sampling interval, the precision (confidence level of 95%) of annual nutrient fluxes obtained by the appropriate methods was 13% for nitrates, 20% for total‐P, 26% for orthophosphates, and 34% for particulate‐P. The frequency of water quality surveys required to obtain an annual nutrient flux with 10% precision was around 15 days for nitrate, 10 days for orthophosphate‐P and total‐P, and about 5 days in the case of particulate‐P. Copyright © 2004 John Wiley & Sons, Ltd.
The MTT assays of bovine retinal pericytes and human microvascular endothelial cells on DLC and Si‐DLC–coated TCPS
Authors: Okpalugo T. I. T. , McKenna E. , Magee A. C. , McLaughlin J. , Brown N. M. D. 
Published: September 2004

AbstractMTT (Tetrazolium)‐assay suggests that diamond‐like carbon (DLC) and silicon‐doped DLC (Si‐DLC) films obtained under appropriate deposition parameters are not toxic to bovine retinal pericytes, and human microvascular endothelial cells (HMEC). The observed frequency distributions of the optical density (OD) values indicative of cell viability are near Gaussian‐normal distribution. One‐way ANOVA indicates that at 0.05 levels the population means are not significantly different for the coated and control samples. The observed OD values depend on the cell line (cell growth/metabolic rate), possibly cell cycle stage, the deposition parameters‐bias voltage, ion energy, pressure, argon precleaning, and the dopant. For colored thin films like DLC with room temperature photoconductivity and photoelectric effects, it is important to account for the OD contribution from the coating itself. MTT assay, not surprisingly, seems not to be highly sensitive to interfacial cellular interaction resulting from the change in the film's nanostructure, because the tetrazolium metabolism is mainly intracellular and not interfacial. The thin films were synthesized by 13.56 MHz RF‐PECVD using argon and acetylene as source gases, with tetramethylsilane (TMS) vapor introduced for silicon doping. This study could be relevant to biomedical application of the films in the eye, peri‐vascular, vascular compartments, and for cell‐tissue engineering. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 201–208, 2004
Quantitative analysis of interconnectivity of porous biodegradable scaffolds with micro‐computed tomography
Authors: Moore Michael J. , Jabbari Esmaiel , Ritman Erik L. , Lu Lichun , Currier Bradford L. , Windebank Anthony J. , Yaszemski Michael J. 
Published: September 2004

AbstractPore interconnectivity within scaffolds is an important parameter influencing cell migration and tissue ingrowth needed to promote tissue regeneration. Methods for assessment of interconnectivity are usually qualitative, restricted to two‐dimensional images, or are destructive. Microcomputed tomography nondestructively provides three‐dimensional (3D) images of intact specimens at high spatial resolutions. We describe an image analysis technique for quantitative assessment of scaffold interconnectivity. Scaffolds were made via a particulate leaching process with 75%, 80%, 85%, and 88% volumetric porogen fractions. Specimens were scanned and resulting 3D, digital images were analyzed with a custom algorithm. A series of virtual, idealized scaffolds were also created for illustration of the algorithm's analysis approach and for its validation. The program calculated accessible void fractions over a range of minimum connection sizes. In real specimens, nearly 100% of the porous volume was connected with outside air for connections greater than or equal to 20 μm in their smallest dimension. In scaffolds made with 75% porogen, the accessible void fraction decreased to 78% if only those connections greater than or equal to 260 μm were considered. The relationship between accessible void fraction and connection size varied as a function of porogen content. The interconnectivity parameter described here may have implications for cell migration and tissue growth into scaffolds. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 258–267, 2004