bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of methyltin compounds related to possible conditions in the environment
Authors: Hamasaki Tetsuo , Nagase Hisamitsu , Sato Takahiko , Kito Hideaki , Ose Youki 
Published: December 2004

AbstractThe methylation of heavy‐metal compounds (e.g. mercury, lead, tin) in the environment has great significance owing to the much higher toxicity of their methyl derivatives in comparison with inorganic metal species.In this paper abiological methylation of inorganic tin is described. Ethanol, acetic acid and propionic acid abiologically methylated inorganic tin, and the highest yield of methyltin was observed in the reaction between inorganic tin(II) and ethanol. Furthermore, environmental factors for the methylation, such as pH, temperature, added ethanol, concentration of sodium chloride and photoirradiation, were investigated in this reaction. Methyltin production increased at low pH, and decreased at higher concentrations of sodium chloride. Photoirradiation accelerated the reaction rate, and a shorter wavelength showed a higher rate. Inorganic tin(II) was converted rapidly into monomethyltin, and gradually transformed into dimethyltin and trimethyltin with the course time.
Tributyltin analysis in seawater by GC FPD after direct aqueous‐phase ethylation using sodium tetrathylborate
Authors: Michel Pierre , Averty Bernard 
Published: December 2004

AbstractUsing sodium tetraethylborate as an alkylation reagent, one‐step ethylation and extraction of organotin compounds in seawater was performed directly in the aqueous phase to obtain optimal rection conditions. No further purification or concentration of the extract was required before GC FPD analysis. The detection limit for monobutyl‐dibutyl‐and tributyl‐tin was approximately 0.4 ng dm−3, which is adequate for any currently know toxicity effect. The linearity range (0–200 ng dm−3) was solely dependent on the detector response curve. Compared with the Grignard reaction after extraction in an organic solvent, this new ethylation procedure reduces the number of analytical steps, thus saving time and improving reliability.
Evaluation of the genotoxic potential of six triorganotin compounds by the mouse micronucleus and spermhead abnormality tests
Authors: Kook Sam Choon , Kwong Ng Meng , Das V G Kumar 
Published: December 2004

AbstractSix triorganotin compounds—Ph3SnOH, BuPh2SnOH, (p‐CIC6H4)Ph2SnOH, (cyclo‐C5H9)Ph2SnOH, Ph3SnO2CCH2CS2NMe2 and Bu3SnOSO2Et—were tested for their mutagenic potential in somatic and germinal cells in ICR mice by using the micronucleus and spermhead abnormality assays, respectively. In somatic cells, the compunds significantly induced chromosomal disorders at half their respective estimated LD50 (i.p.) values (5.00–6.25 mg kg−1 body wt), and one compound, Ph3SnOH, even at 1/20 of its estimated LD50 value. In germinal cells, five compounds significantly induced chromosomal disorders at 1/64 of their respective estimated LD50 (i.p.) values, whereas one, (p‐CIC6H4)Ph2SnOH, caused such disorders only at 1/8 of its estimated LD50 value.
Synthesis, spectroscopic characterization and in vitro antitumour activity of di‐n‐butyltin and diethyltin trimethoxybenzoates: X‐ray structure analysis of bis[di‐n‐butyl(3,4,5‐trimethoxybenzoato)tin] oxide
Authors: Gielen Marcel , Meunier‐Piret Jacqueline , Biesemans Monique , Willem Rudolph , El Khloufi Abdelaziz 
Published: December 2004

AbstractDi‐n‐butyltin(IV) and diethyltin(IV) 2,3,4‐, 2,4,5‐ and 3,4,5‐trimethoxybenzoates [(CH3O)3C6H2COO]2SnR [Type a] and {[(CH3O)3C6H2COO]R2Sn}2O [Type b] have been synthesized and characterized spectroscopically.The crystal structure of bis[di‐n‐butyl(3,4,5‐ trimethoxybenzoato)tin] oxide has been determined. The triclinic unit cell contains one centrosymmetric dimer; a = 15.919(2) Å, b = 11.711(3) Å, c = 13.475(1) Å, and α = 63.63(2)°, β = 67.49(1)°, γ = 76.61(2)°. The geometry of the dimer is very similar to that of bis[di‐n‐butyl(5‐methoxysalicylatotin] oxide), with two different types of five‐coordinate tin atoms and one central planar Sn2O2 ring.
Chemically induced chromosome damage in early‐developing embryos of Anilocra physodes L. (Crustacea, Isopoda) following exposure to bis[Dimethyltin(IV)Chloro]protoporphyrin IX
Authors: Vitturi R , Catalano E , Conte M R Lo , Pellerito L 
Published: December 2004

AbstractIn order to obtain chromosome preparations from early‐developing embryos of Anilocra physodes, a squash technique has been successfully employed.Results gathered after exposure of this material to bis[dimethyltin(IV)chloro]protoporphyrin IX {[(CH3)2SnCl]2 ‐ Protoporphyrin IX} solutions at different exposure times suggest that this chemical complex is capable of producing abnormal metaphase and anaphase figures in proportion to its concentration and not to exposure length.Essentially, all of the chromosome abnormalities are classifiable as chromosome fragments mainly observed at the metaphase stage; chromosome bridges; and large decondensed chromosome regions.
Erzeugung dünner Schichten: neue Herausforderungen für die Metallorganische Chemie
Authors: Fischer Roland A. 
Published: December 2004

AbstractDie Metallorganische Chemie der Precursor für dünne Schichten und Schichtstrukturen ist ein junges Forschungsgebiet, in dem es, wie in vielen anderen Bereichen der modernen Chemie, weniger um die Verwirklichung völlig neuer Molekülstrukturen und Bindungsverhältnisse geht als vielmehr um ein vertieftes Verständnis und eine strategischökonomische Ausnützung chemischer Reaktivitäten. Nur ein fundamentales Verständnis aller vom molekularen Precursor bis zum endgültigen Material zu durchlaufenden Teilschritte kann hier langfristig erfolgsversprechend sein. Die Konstitutions‐ und Strukturvielfalt metallorganischer Komplexverbindungen bietet einen reichen Schatz an Möglichkeiten für die Synthese neuer Materialien. Die Erzeugung dünner Schichten durch Chemische Dampfabscheidung aus maßgeschneiderten flüchtigen Organometallverbindungen als Precursor, denen dieser Beitrag gewidmet war, stellt daraus nur einen kleinen Ausschnitt dar.
Molekulare Evolution funktionaler Nukleinsäuren
Authors: Schwienhorst Andreas 
Published: December 2004

AbstractIn recent years biologists succeeded in applying strategies of natural evolution to the design of novel compounds. On the basis of large and highly diverse libraries molecules with desired properties are selected. In particular nucleic acids proved to be well suited to adopt a whole variety of functions, including high affinity target binding, specific inhibition of pharmaceutically relevant enzymes, substrate function and various catalytic activities. Altogether, the results brought considerable progress in the field of pharmaceutical drug design as much as they stimulated research on the origin of life. In particular, the theory of an early „RNA world”︁ preceeding our present DNA‐protein‐world has since gained a lot of plausibility.
Die Rolle des Aerosols im Klimasystem
Authors: Heintzenberg Jost 
Published: December 2004

AbstractDer Stand unseres Wissens zum Kreislauf des Atmosphärischen Aerosols und von seiner Rolle im Klimasystem läßt sich wie folgt zusammenfassen:

Unser Verständnis des globalen Aerosolkreislaufs und vor allem des menschlichen Eingriffs in denselben ist noch sehr unvollständig. Dies gilt in hohem Maße auch für die mit diesem Kreislauf verbundenen chemischen Mehrphasenprozesse.
Ein negativer direkter Klimaantrieb anthropogener Aerosole existiert über die Streuung und Absorption, hat aber noch große Unsicherheiten und kann über hoch mit Rußpartikeln belasteten Gebieten auch positive Werte annehmen.
Ein indirekter Klimaantrieb anthropogener Aerosole existiert wahrscheinlich und hat ebenfalls ein negatives Vorzeichen. Seine Größenordnung und Unsicherheiten lassen sich noch nicht quantifizieren.
Nanostrukturierung von Festkörpern mit amphiphilen Polymeren
Authors: Göltner Christine , Cölfen Helmut , Antonietti Markus 
Published: December 2004

AbstractAmphiphilic block copolymers are versatile structure‐directing agents for the synthesis of organic nanostructured materials. Chemically well characterized and easily accessible, they can be utilized for a rich variety of applications. While the prefabrication of an ABC “nanoreactor” or a mesoscopic casting mold occur via spontaneous self‐assembly (exo‐and endo‐templating), during biomimetic mineralization the structure of the resulting inorganic‐ABC hybrid material is induced upon combining thc components. The underlying methodologies are illustrated using recently published, representative examples.
Quantitative morphological changes in visual centers in rats after unilateral deprivation
Authors: Fifková E. , Hassler R. 
Published: December 2004

AbstractThe effect of visual deprivation on the morphology of the primary and secondary visual centers was studied. The deprivation was achieved by unilateral lidsuture in 14 or 15 day old white rats before eye opening. The animals were kept for 8‐9 weeks in larger cages where they were exposed to different kinds of visual stimulation and had greater movement opportunity. The asymmetry was revealed by means of volume measurement and cell counting. No changes could be found in the optic tract and superior colliculus. The volume differences on the side supplied by the deprived eye were found in the dorsal part of the lateral geniculate body −5.07%, and in the primary visual area −16.0%. Cell counting revealed asymmetry in the dorsal part of the lateral geniculate body −13.5%, as well as in the pulvinar −7.0%. No consistent difference in cell density could be found in cortical Iayer V of area 17, whereas in layer IV there were relatively more cells +11.5% on the side connected with the deprived eye. The changes in different centers related to the visual pathway were of different intensity according to the proposed role in transmitting different kinds of visual information.
Efferent tectal pathways of the opossum (Didelphis virginiana)
Authors: Martin George F. 
Published: December 2004

AbstractEfferent tectal pathways have been determined for the opossum, Didelphis virginiana, by employing the Nauta‐Gygax technique ('54) on animals with tectal lesions of varying sizes. The superior colliculus projected tectothalamic fascicles to the suprageniculate nucleus, the central nucleus of the medial geniculate body, the lateral posterior thalamus, the pretectal nucleus, the ventral lateral geniculate nucleus, the fields of Forel and zona incerta, the parafascicular complex, the paracentral thalamic nucleus and in some cases to restricted areas of the anterior thalamus. Degenerating fibers from superior collicular lesions showed profuse distribution to the deeper layers of the superior colliculus on both sides and to the midbrain tegmentum, but only minimally to the red nucleus and substantia nigra. Fibers of tectal origin did not distribute to the motor nuclei of the oculomotor or trochlear nerves. At pontine levels, efferent fascicles from the superior colliculus were present as an ipsilateral tectopontine and tectobulbar tract and as a crossed predorsal bundle. The tectopontine tract ended mostly within the lateral and ventral basal pontine nuclei, whereas the ipsilateral tectobulbar tract distributed to certain specific areas of the reticular formation throughout the pons and medulla, minimally to the most medial portion of the motor nucleus of the facial nerve and to the nucleus of the inferior olive. The predorsal tract contributed fascicles to certain nuclei of the pontine raphe, extensively to the medial reticular formation of the pons, to the central and ventral motor tegmental nuclei of the reticular formation within the pons and medulla, to the paraabducens region, minimally to cells within restricted portions of the motor nucleus of the facial nerve, to certail specific regions of the caudal medulla and to the cervical cord as far caudally as the fourth segment. The tectospinal fascicles were few but some ended related to the spinal accessory nucleus and the ventral medial nucleus of the ventral horn.Lesions of the inferior colliculus resulted in degenerating fibers which distributed rostrally to the rostral nucleus of the lateral lemniscus and parabrachial region, to the suprageniculate nucleus, the parabigeminal nucleus and to the central nucleus of the medial geniculate body. The inferior colliculus also contributed fibers to the ipsilateral tectopontine and tectobulbar tracts. The latter bundle was traced as far caudally as the medulla and may arise from cells of the superior colliculus which are situated dorsal to the nucleus of the inferior colliculus.
Two and three dimensional ultrastructure of boutons and glial cells on the motoneuronal surface in the cat spinal cord
Authors: Poritsky Raphael 
Published: December 2004

AbstractA method is presented for individually mounting serial sections on one‐hole specimen holders. Also a technique for constructing stereograms based upon serial sections is described including a method for obtaining perspective foreshortening. Ultrastructural findings revealed the surface of the motoneuron to be covered with synaptic boutons which frequently pressed against each other. Surface area not contacted by boutons was covered with astroglial processes. The latter processes wedged around and sometimes between the boutons. On occasion finger‐like astrocytic processes (spines) were found to invaginate the terminal boutons. No synaptic thickenings were found between adjacent boutons (axo‐axonal contacts) on the perikaryal surface. However, in view of the enormous size of the motoneuron contrasted to the small volume of tissue thus far investigated, this observation is regarded as inconclusive. Three‐dimensional studies revealed an astrocytic process with disproportionately large amounts of surface membrane in the form of many interconnected pockets. The initial unmyelinated segment of a large anterior horn cell was encountered and found to have synaptic boutons on its proximal half. Its distal half was surrounded by an extracellular space containing electron dense material similar to that found in the goldfish by Robertson, Bodenheimer, and Stage ('63).
The visual pathways of the lorisid lemurs (Nycticebus coucang and Galago crassicaudatus)
Authors: Laemle Lois Kalus , Noback Charles R. 
Published: December 2004

AbstractThe primary projections of the optic nerve were investigated in two species of lorisid lemurs (Nycticebus coucang and Galago crassicaudatus) following unilateral enucleation of an eye. In addition, the cytoarchitecture of the lateral geniculate body and of the pretectum is described. The lateral geniculate nucleus is composed of six cellular laminae – four magnocellular and two parvocellular. Optic nerve fibers from the retina of an eye terminate in laminae 1, 5 and 6 of the lateral geniculate body on the side opposite to the enucleated eye and laminae 2, 3 and 4 of the lateral geniculate body on the same side as the enucleated eye. Retinofugal fibers were also observed to project to the pregeniculate nucleus, nucleus of the optic tract, pretectal nucleus and superior colliculus on both the same side as and on the side opposite to the enucleated eye. A completely crossed accessory optic tract was noted. The lateral geniculate bodies of a Galago “borgne” (one blind atrophic eye) are also described.
The retinofugal fibers and their terminal nuclei in Galago crassicaudatus (primates)
Authors: Tigges Margarete , Tigges Johannes 
Published: December 2004

AbstractControl and experimental brains of Galago were used to study the subcortical optic nuclei and their retinal input. Weil, Nissl and Fink‐Heimer methods were employed.The pregeniculate nucleus receives predominantly contralateral retinal input. Terminal degeneration is found only in its pars grisea, but not in its pars fibrosa. The lateral geniculate nucleus exhibits seven demonstrable laminae. Laminae 0, 2, 3 and 4 receive ipsilateral retinal input, whereas laminae 1, 5 and 6 receive contralateral input without overlap. In Fink‐Heimer preparations only the ipsilateral lamina 4 and the contralateral lamina 5 show clusters of argyrophilic spherules which probably indicate axo‐dendritic termination of retinofugal fibers. The nucleus praetectalis posterior and nucleus tractus optici receive predominantly contralateral retinal input. In all likelihood, only the stratum griseum superficiale of the superior colliculus receives retionfugal fibers. On the basis of the very remarkable pattern of terminal degeneration, we divide this stratum into substrata A, B and C. The ipsilateral superior colliculus receives retinal input to its substratum B and the contralateral superior colliculus receives retinal input to its substratum A only. Substratum C receives probably no retinal input.
The pathway from the medial geniculate body to the ectosylvian auditory cortex in the dog
Authors: Tunturi Archie R. 
Published: December 2004

AbstractLesions of the medial geniculate body showed Marchi degeneration to the dorsal pörtion of the anterior ectosylvian gyrus and the entire middle ectosylvian gyrus in the dog. The fibers passed under the arcuate fibers terminating under the entire dorso‐ventral width of the gyrus. Few fibers were found to enter the cortex itself.No degeneration was found in the third auditory cortex, in the lower portion of the anterior ectosylvian gyrus, or in the PES area located on the posterior ectosylvian gyrus. Degeneration was greatest at the anterior portion of the MES area and diminished toward the caudal end.No degeneration was found in the sylvian or the suprasylvian gyri (late association in the cat).
The vascular anatomy of the rat's hypothalamus in stereotaxic coordinates
Authors: Scremin Oscar U. 
Published: December 2004

AbstractThe vascular antomy of the rat's hypothalamus was studied using the method of the India ink injections. A constant vascular pattern was found and a serial description of it is given, correlated with the nuclear and fibrilar anatomy in a system of stereotaxic coordinates.It was found that the vessels supplying certain areas follow a relatively long course and the hypothesis is advanced that their lesion could produce vascular disturbances in areas distant to that in which the electrode had been placed.Some previous results by other authors are discussed on these grounds.
Corticocortical fiber connections in the cat cerebrum: The frontal region
Authors: Kawamura Koki , Otani Katsumi 
Published: December 2004

AbstractThe Nauta silver degeneration technique was used to study the interconnections of the frontal cortex of the cat. The sensorimotor area is found to be highly organized through intrinsic short association fibers. However, less specific connections are‐revealed with other areas; for example, no direct fibers are recognized as passing from the sensorimotor cortex to the visual area. In the sensorimotor area, the association fibers from the first (SI) to the second somatic sensory area (SII) are generally denser than those passing in the reverse direction, particularly in regard to the leg subdivisions. Such a difference in density is less striking in regard to the arm subdivisions and much less in the face subdivisions.Long association fibers arise only from the first face area to the middle suprasylvian sulcus, a connection which may correspond to the superior longitudinal fasciculus in man. The number of callosal fibers connecting the homotopical regions between both hemispheres differs for each portion of the cortex. Callosal interconnections are doubtful for the gyrus proreus and the medial portion of both the anterior and posterior sigmoid gyri, While they appear sparse in the lateral portion of the latter gyri. Dense interconnections, by contrast, are seen in the coronal and anterior ectosylvian gyri.The degenerating fibers seen in layers V and VI mainly appear to represent fibers of passage, and those in layers III and IV seem to be Preterminal fibers.
Stereotaxic atlas of the hypothalamus of the Mongolian gerbil (Meriones unguiculatus)
Authors: Thiessen D. D. , Goar S. 
Published: December 2004

AbstractA stereotaxic atlas of the hypothalamic area of the Mongolian gerbil (Meriones unguiculatus) is presented along with medical coordinates for all primary nuclei and the third ventricle.
The cerebellar nuclei of Macaca mulatta: A morphological study
Authors: Courville J. , Cooper C. W. 
Published: December 2004

AbstractThe cerebellar nuclei of the macaque have been studied morphologically and illustrated in three planes: transverse, horizontal and sagittal. It was fourn that the nucleus interpositus consists of two distinct cell groups. These nuclei are named nucleus interpositus anterior (NIA) and posterior (NIP) since many of their features resemble those of NIA and NIP of the cat. Both nuclei are also distinct from the lateralis (NL) and the medialis (NM). The characteristics of the cell populations forming the various nuclei have been described and measurements of cell diameters of large samples have been made. Numerous small neurons scattered evenly throughout all four nuclei were also observed.
Medullary cells of origin of vagal cardioinhibitory fibers in the pigeon. I. Anatomical studies of peripheral vagus nerve and the dorsal motor nucleus
Authors: Cohen David H. , Schnall Adrian M. , Macdonald Robert L. , Pitts Lawrence H. 
Published: December 2004

AbstractThe organization to the dorsal motor nucleus of the vagus in the pigeon was studied in an attempt to localize the cells of origin of vagal cardioinhibitory fibers. The course of the peripheral vagus nerve is described form the intracranial rootlets to abdominal levels. Using combined microdissection and electrical stimulation techniques, the branches which mediate cardiodeceleration are found to arise from a localized segment of the vagal trunk below the thoracic ganglion, and above the level where the left and right vagi join.The dorsal motor nucleus, its cytoarchitectonic divisions, and other structures connected with vagal rootlets are described on the basis of normal material.Utilizing the above findings a series of retrograde degeneration experiments was undertaken. The distribution of chromatolytic neurons following cervical vagotomy was described to indicate the extent of the dorsal motor nucleus. Selective nerve sections (abdominal vagotomy, cardiac vagotomy, recurrent laryngeal neurotomy, or pneumonectomy) then indicated that there is an incompletely inverted topographic representation of the vagus nerve in the dorsal motor nucleus, including a representation of the recurrent laryngeal nerve; no evidence was found for the existence of a nucleus ambiguus. The vagal cardioinhibitory fibers appear to be represented throughout the rostral half of the nucleus, but they are most concentrated in the ventral portion of the nucleus, approximately three‐quarters of a millimeter rostral to the obex.