bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the ligand structure on SLP‐catalysed hydroformylation of propene
Authors: Hjortkjaer Jes , Heinrich Bernd , Čapka Martin
Published: December 2004

Hydroformylation of propene was studied at 90–120°C and 3–10 atm. The catalyst was hydrido‐(carbonyl)tris(triphenylphosphine)rhodium [H(CO)Rh(PPh3)3] supported on silica, in an excess of a liquid phosphine (P) ligand as solvent. The following series of ligands (P) was synthesized and studied in this application: CH3(CH2)nPPh2 (n = 3, 7, 17), (c – C6H11)xPPh3−x (x = 0, 1, 2) and also unsaturated allyl‐ and poly(butadienyl)‐diphenylphosphines. The activity and regioselectivity of the catalysts are discussed in terms of the mobility and coordination ability of the ligands used. With the same electron density of the phosphorus atom, the activity of the catalysts increases with the mobility of the ligands. On the other hand, given the same mobility of the ligand, a lower electron density on phosphorus results in increased catalytic activity.
Useful and accessible organometallic precursors for preparation of zinc sulfide and indium sulfide thin films via solution pyrolysis (printing) method
Authors: Nomura Ryǒki , Konishi Kazuhisa , Futenma Satoshi , Matsuda Haruo
Published: December 2004

Polycrystalline β‐zinc sulfide thin films were prepared by solution pyrolysis of an ethylzinc isopropylthiolate–zinc bis(dibutyldithiocarbamate) combined precursor (EtZnSiPr–Zn(S2CNnBu2)2) in chloroform solution on glass or silicon(111) substrates at 300°C. Homogeneous but amorphous indium sulfide thin films were obtained from butylindium bis(isopropylthiolate) (nBuInSiPr2) in P‐xylene on these substrates at 300°C similarly. The sulfide thin films obtained were characterized by means of X‐ray photoelectron spectroscopy (XPS), X‐ray fluorescence Microanalysis, scanning electron microscopy (SEM) and optical band gap measurements.
Studies of the uptake and binding of trace metals in fungi. Part II. Arsenic compounds in Laccaria amethystina
Authors: Byrne Anthony R , Tušek‐Žnidarič Magda , Puri Bal K , Irgolic Kurt J
Published: December 2004

Caps of the edible mushroom Laccaria amethystina collected during September and October at forested sites in the vicinity of the town of Domzale in Central Slovenia, Yugoslavia, were found by neutron activation analysis (NAA) and hydride generation to have total arsenic concentrations between 109 and 200 mg As kg−1 (dry mass). The extraction of fresh, frozen or freeze‐dried caps with cold Tris buffer at pH 7.6, or with boiling water, transferred 60–70% of the arsenic into the aqueous phase. Sephadex gel permeation chromatography indicated that the arsenic compounds in these extracts were not associated with proteins or other organic compounds of molecular mass larger than 4000 Dal.

Cation‐exchange chromatography coupled with NAA, hydride generation, and reverse‐phase chromatography with arsenic‐specific detection (HPLC ICP) showed that dimethylarsinic acid is the major arsenic compound in the extracts. Methylarsonic acid and arsenate account for no more than 10% each of the total arsenic.
A synergistic organoiron flame‐retarding/smoke‐suppressing system for ABS
Authors: Carty P , White S
Published: December 2004

Commercial acrylonitrile butadiene styrene (ABS) polymers are among the most flammable of the currently available range of thermoplastic materials. In addition to having a rather low limiting oxygen index (LOI) value in the range 18.3–18.8, ABS polymers also produce compious amounts of smoke and hazardous gases when burnign in the air. In a recent study directed towards preparing and evaluating compounds which would simultaneously reduce the flammability and smoke produced from burning thermoplastic polymers, a synergistic flame‐retarding/smoke‐suppressing system based on organoiron compounds has been produced, which when properly compounded into ABS/PVC [poly(vinyl chloride)] blends more than doubles the LOI nad at the same time reduces smoke production significantly.
Determination of arsenic and arsenic compounds in natural gas samples
Authors: Irgolic Kurt J , Llger Drew , Zingaro Ralph A , Spall Dale , Puri B K
Published: December 2004

Organic arsenic compounds (trialkylarsines) present in natural gas were extracted by 10 cm3 of concentrated nitric acid from 1 dm3 of gas kept at ambient pressure and temperature. The flask containing the gas and the acid was shaken for 1 h on a platform shaker set at the highest speed. The resulting solution was mixed with concentrated sulfuric acid and heated to convert all arsenic compounds to arsenate. Total arsenic was determined in the mineralized solutions by hydride generation. The arsenic concentrations in natural gas samples from a number of wells in several gas fields were in the range 0.01–63 μ As dm−3. Replicate determinations of arsenic in a gas sample with an arsenic concentration of 5.9 μ dm−3 had a relative standard deviation of 1.7%. Because of the high blank values, the lowest arsenic concentration that could be reliably determined was 5 ng As dm−3 gas. Analysis of nonmineralized extracts by hydride generation identified trimethylarsine as the major arsenic compound in natural gas. Low‐temperature gas chromatography‐mass spectrometry showed more directly than the hydride generation technique, that trimethylarsine accounts for 55–80% of the total arsenic in several gas samples. Dimethylethylarsine, methyldiethylarsine, and triethylarsine were also identified, in concentrations decreasing with increasing molecular mass of the arsines.
Leaching of organotin compounds from poly(vinyl chloride) (PVC) material
Authors: Quevauviller Ph , Donard O F X , Bruchet A
Published: December 2004

The release of mono‐and di‐butyltin species (MBT and DBT) in water after leaching of five different poly(vinyl chloride) (PVC) materials was investigated under mild conditions over a period of one month in batch reactor systems. Results showed that inorganic tin, MBT and DBT compound were released from the material tested under experimental static leaching conditions. The total amount of inorganic tin and organotin compounds observed upon leaching varied considerably from one PVC material to another.
The use of metallocenic esters of n‐hydroxysuccinimide for metallohapten synthesis
Authors: Lavastre I , Besançon J , Brossiert P , Moise C
Published: December 2004

Different organometallic markers have been described in a new technique for the labelling of many drugs. Thus metallocenic esters of
magnified image
[M = (;CO)3CrC6H5; (;CO)3CrC6H5(;CH2)3; η‐C5H5FeC5H4; (;CO)3MnηC5H4; (;CO)3MnηC5H4COCH2CH2; ηC5H4(;ηC5H5)Co+PF−6] react with primary or secondary amine drugs [DRUGNHR] for a psychostimulant drug: amphetamine; tricyclic antidepressants—desipramine and nortriptyline; a vasodilator—histamine; an adrenergic substance—norfenefrine; and for a central stimulant—meth‐amphetamine, to give the metallohaptens MCON(;R)—DRUG. All these compounds have been fully characterized by different analytical methods and have potentialities for biological assays. This synthetic route was found better than one presented previously which utilized the metallocenic acid chloride MCOCI as intermediate, and could be proposed as a general synthetic route for labelling biological compounds which possess an amino group.
Determination of butyltin species by GC/atomic emission spectroscopy
Authors: Scott B F , Chau Y K , Rais‐Firouz A
Published: December 2004

A commercially available atomic emission detector coupled to a capillary column‐containing gas chromatograph (;GC/AE) was utilized to detect organotin compounds. The response for tin was found to be dependent on the flow rate of the make‐up gas. At flow rates of 174 cm3 min−1, 6 × 10−12 g of tin could be detected. Lower flow rates decreased the sensitivity. Response curves for two different pressures were established and both plots exhibited curvature at low concentrations. Extracted fish and sediment samples were analysed on the GC/AE system. The technique is element‐specific. The presence of tin compounds could be confirmed by examining the emission spectra taken at the retention time of the peak.
Catalytic ethylation of alkylbenzenes at high pressure
Authors: Assadourian L , Gau G
Published: December 2004

Study of the catalytic ethylation of p‐t‐butyltoluene in the presence of organosodium compounds, and of toluene in the presence of organopotassium compounds, was carried out at an ethylene pressure of 40 bar.

Various yields of different products were obtained after 23 h of reaction in the presence of different tertiary polyamines used to complex and solubilize the organoalkali compounds.

A higher initial ethylation rate was observed in the presence of organosodium than in the presence of organopotassium species. However, the thermal stability of organopotassium species being higher, much higher yields were observed in their presence in catalytic ethylation reactions than those observed previously.

The results obtained concerning metallation or ethylation of hindered alkylaromatics may be interpreted by an anionic mechanism and the activation by a steric effect.
Synthesis, characterization and in vitro antitumour properties of complexes of bis(alkoxycarbonylmethyl)tin dibromides with bidentate nitrogen ligands
Authors: Zhang Zhengquan , Pan Huade , Hu Chun , Fu Fangxin , Sun Yunhong , Willem Rudolph , Gielent Marcel
Published: December 2004

The synthesis and characterization of 10 new bis(;alkoxycarbonylmethyl)tin dibromides and of 14 of their complexes with bidentate nitrogen ligands (;bipyridyl, 1,10‐phenanthroline and 5‐nitro‐1, 10‐phenanthroline) are described. Their proton NMR spectra are discussed. Their in vitro antitumour activity against two human cancer cell lines, MCF‐7 and WiDr, is low compared to antitumour drugs used clinically.
Synchrotron radiation‐stimulated photochemical reaction and its application to semiconductor processes
Authors: Urisu Tsuneo , Takahashi Jun‐Ichi , Utsumi Yuichi , Akazawa Housei
Published: December 2004

Recent results are reviewed on synchrotron radiation (SR)‐excited photochemical reaction studies aimed at applications to semiconductor processes. Valence or core electronic excitations induced by SR irradiation and ensuing chemical reactions are classified and characterized by rate equations. Unique material selectivity in etching has been found. SiO2 has been found to evaporate by SR irradiation and this phenomenon can be applied to the low‐temperature surface cleaning of silicon. In the epitaxial growth of Silicon by ultrahighvacuum chemical vapor deposition using Si2H6, SR irradiation significantly lowers growth temperature beyond the low‐temperature limit of thermal reaction. Lowering of the operating temperature by SR irradiation is especially effective in applications to the atomic layer epitaxial growth of silicon. The layer‐by‐layer process has been successfully demonstrated, confirming self‐limiting adsorption of SiH2Cl2 and ensuring surface reactivation by SR irradiation.
Photo‐Absorption and photochemical decomposition of copper and alkaline‐earth ß‐diketonates as source gases of high‐Tc superconducting films
Authors: Hashimoto Takuya , Kitazawa Koichi , Nakabayashi Masaaki , Shiraishi Tadashi , Suemune Youichi , Yamamoto Takakazu , Koinuma Hideomi
Published: December 2004

For low‐temperature deposition of oxide films relating to Bi‐Sr‐Ca‐Cu‐O superconductors, photo‐absorption and ‐decomposition properties were examined with respect to copper and alkaline‐earth ß‐diketonates. It was confirmed that all ß‐diketonates examined were promising as source materials for photochemical vapour deposition (photo‐CVD) using a low‐pressure mercury lamp, in view of their large light absorption coefficients at wavelength 254 nm. The light irradiation was effective for the formation of highly crystalline oxide films at temperatures below 600 °C. By combining two sources, Ca2CuO3 and SrCuO2 films were prepared. Photo‐CVD of c‐axis oriented Bi2Sr2CuOx film was achieved by the irradiation of ternary sources of Bi(C6H5)3 and strontium and copper ß‐diketonates at 500 °C.
The epitaxial growth of gaas using alkylarsine: Part 2. molecular orbital calculation
Authors: Kikuzono Y , Maeda T
Published: December 2004

Semi‐empirical molecular orbital calculations were carried out for the compounds (C2H5)3As, (C2H5)3Ga and RAsH2 (R = C2H5, i‐C3H7, i‐C4H9, and t‐C4H9) by using the CNDO/2‐U program, and their capability of β‐elimination reaction is compared on the basis of the torsion energy to the transition state, electrostatic interactions and orbital overlapping between the central atom and the β‐hydrogen, and bond order of the metal‐carbon, and carbon‐hydrogen bond. In the comparison of (C2H5)3As with (C2H5)3Ga, we found that the β‐elimination of (C2H5)3As could hardly be expected to take place in the thermal decomposition. The capability of β‐elimination would be smaller in C2H5AsH2 than that in (C2H5)3As. Moreover when the ethyl group is replaced by a t‐butyl group in RAsH2, the β‐elimination reaction appears to become more difficult and a large possibility for a radical process is suggested.
Biomonitoring in the mercury‐contaminated Wabigoon–English–Winnipeg river (Canada) system: selecting the best available bioindicator
Authors: Parks J W , Craig P J , Neary B P , Ozburn G , Romani D
Published: December 2004

Several organisms used for biomonitoring in the mercury‐contaminated Wabigoon–English River System, Ontario, Canada (sport fish, forage fish, crayfish and others) were examined for their utility as bioindicators. Causes for spatial and temporal variability in mercury concentrations in biota are reviewed. The significance of intertrophic and intratrophic biotic relationships is evaluated on both a site‐specific and intersite basis. Larger mature fish are the most effective integrators as these organisms are the most buffered from site‐specific and seasonal variations in mercury concentrations and bioavailability. Where there are no physical barriers preventing movement of biota between contaminated and uncontaminated parts of the watercourse, younger, smaller organisms can better ‐ ical zones of contamination because of their restricted range. Because many organisms can provide information on mercury contamination, the choice of the most suitable indicator depends upon the purpose of the study, the pharmacokinetics of mercury uptake by the organisms in question, and the chemodynamics of methyl and inorganic mercury species in the field.
Alkane activation by homogeneous palladium complexes
Authors: Beattie James K , Masters Anthony F , Sparkes Meredith L
Published: December 2004

The conversion of adamantane exclusively to 1‐adamantyl trifluoroacetate in a refluxing trifluoroacetic acid solution of palladium acetate at 1 atm of air or nitrogen was confirmed. The conversion can be made quantitative. The 1‐adamantyl trifluoroacetate was hydrolysed to yield 1‐adamantanol in 90% isolated yield. The adamantane functionalization is accompanied by concomitant formation of a palladium mirror.
Speciation and GC retention indices of some organotin compounds in water
Authors: Rosales Daniel , Pablos Fernando , Marr Iain L
Published: December 2004

Analytical methods have been developed for the quantitative determination of Bu4Sn, Bu3Sn+, Bu2Sn2+, BuSn3+, Me3BuSn, Me2Bu2Sn, MeBu3Sn, MeBuSn2+, Me2BuSn+ and MeBu2Sn+ in water. Organotin compounds are extracted from water with tropolone at 0.1 % in n‐pentane, derivatized with n‐pentylmagnesium bromide and determined by gas chromatography with flame photometric detection or flame ionization detection. Absolute detection limits are 0.05‐0.12 ng and 1.2‐13 ng as tin, respectively. The method was applied to the analysis of spiked tap‐water containing 0.3‐1000 ng cm−3 of each of the organotin compounds.
Synthesis and spectroscopic characterization of diethyltin (IV) derivatives of dipeptides: Crystal and molecular structure of diethyltin glycyltrosinate
Authors: Vornefeld Michael , Huber Friedo , Preut Hans , Ruisi Giuseppe , Barbieri Renato
Published: December 2004

Dipeptide complexes of the diethyltin(IV) moiety, Et2SnL, have been synthesized, H2L being glycylglycine (H2GlyGly), glycylalanine (H2GlyAla), alanylalanine (H2AlaAla), glycylvaline (H2GlyVal), valylvaline (H2ValVal), glycylmethionine (H2GlyMet), glycyltyrosine (H2GlyTyr). The crystal and molecular structure of the complex Et2SnGlyTyr has been determined by singlecrystal X‐ray diffraction. It consists of monomeric units, with the tin atom having a considerably distorted trigonal bipyramidal environment. The dipeptide acts as a tridentate ligand bonding the tin of the C2Sn fragment (equatorial carbon atoms) with the peptide nitrogen atom (equatorial) and axial (monodentate) carboxyl oxygen and amino nitrogen atoms, into a monomeric unit. Bond lengths and angles are reported. Infrared spectroscopic data show the occurrence of monodentate carboxyl in all solid compounds, as well as in methanol solutions of some representative complexes. 119Sn Mössbauer spectroscopic data, and their rationalization through point‐charge model (literal version) calculations of the parameter nuclear quadrupole splitting (ΔE) confirm the general occurrence of trigonal bipyramidal structures of the Et2SnGlyTyr type, in the solid state, and give evidence of variations of the CSnC angle in the individual Et2SnL species. Monomers occur in CH3OH solution as suggested by osmometric measurements. 13C and 119Sn NMR spectroscopic data in CD3OD show the persistence of the solid‐state structures also in the solution phase, where the order of magnitude of the CSnC angles, as estimated from the coupling constants |1J(119Sn,13C)|, corresponds to that shown by Et2SnGlyTyr in the solid state. 119Sn Mössbauer parameters of Et2SnGlyGly in frozen CH3OH solution are consistent with the assumptions from the NMR studies.
Anmerkungen zum Aufsatz „Wozu Philosophie der Chemie?”︁
Authors: Stork Heinrich , Metz Peter , Janich Peter
Published: December 2004

„Der Dialog ist eröffnet”︁ – mit dieser Aufforderung schloß das Editorial zum oben genannten Beitrag von Peter Janich in Heft 3/94 der „Chemie in unserer Zeit”︁. Danke an Heinrich Stork und Peter Metz, die in Form von Leserbriefen zum Dialog beigetragen haben. Ihre Bemerkungen und die Antworten von Peter Janich sind im folgenden wiedergegeben.
The rostral projections of the primate vestibular nuclei: An experimental study in macaque, baboon and chimpanzee
Authors: Tarlov Edward
Published: December 2004

The ascending projections of the vestibular nuclei were studied with the selective silver methods of Nauta‐Gygax (Nauta,'57), Voneida ('67) and Fink et al. ('67) in macaque, baboon and chimpanzee. Degenerated axons pass from lesions in the vestibular nuclei into the medial medullary and pontine tegmentum bilaterally, the abducens nuclei, the contralateral vestibular complex and in the medial longitudinal fasciculus to the nuclei of the III and IV nerves. A few fibers pass rostral to the oculomotor complex into the interstitial nuclei of Cajal, the nuclei of Darkshewitsch and the nuclei of the posterior commissure. No degenerated fibers originating in vestibular nuclear lesions were observed to ascend rostral to the level of the posterior commissure. Degenerated fibers rostral to this level could be traced, in sagittal, horizontal and frontal sections, to incidental damage to the superior cerebellar peduncle and the posterior column nuclei. Damage to the acoustic striae produced ascending degeneration in the auditory system, but this did not pass rostral to the inferior colliculus. The incidentally damaged tracts could be seen, in sections in three planes, to be separate in their course and terminations from the fibers ascending from the vestibular nuclei in the medial longitudinal fasciculus.

The experimental evidence lends no support to the supposition that direct secondary vestibular connections to the diencephalon exist. Previous anatomical descriptions of direct vestibulothalamic connections appear to result from failure to discriminate between fibers originating in the vestibular nuclei and fibers arising in adjacent regions. Vestibular impulses reaching the diencephalon must pass over third or higher order neurons after synapse at lower levels.
Degeneration and regeneration of hypothalamic nerve fibers in the neurohypophysis after pituitary stalk section in the ferret
Authors: Adams James Hume , Daniel Peter Maxwell , Prichard Marjorie Mabel Lucy
Published: December 2004

Transection of the pituitary stalk caused rapid and severe degeneration of the hypothalamo‐hypophysial nerve tract distal to the operation site. When a barrier had been inserted to prevent reunion of the stalk this degeneration was permanent. All nerve fibers and stainable neurosecretory material (NSM) disappeared. When a barrier was not used the initial degeneration was followed by regeneration. From two weeks after operation new nerve fibers from the hypothalamus, carrying NSM, were found growing through the scar and down the degenerated lower infundibular stem towards the infundibular process, which was fully re‐innervated by the end of a year. The re‐innervated lower infundibular stem contained an abnormally large amount of NSM. In many cases an outgrowth of nerve fibers from the regenerating tract had invaded the rostral end of pars distalis; these also were surrounded by NSM. Another unusual feature often seen was an ectopic infundibular process which had developed not far below the site of operation.

In its capacity for vigorous regeneration the hypothalamo‐hypophysial nerve tract appears to be unique among tracts of the central nervous system. It is suggested that this regenerative capacity may be related to the fact that this tract is composed of non‐myelinated nerve fibers.
Peripheral synaptogenesis in nerve parabiosis
Authors: Estable Clemente , Reissenweber Nelson J. , Benedetti Washington L.
Published: December 2004

One hundred and ninety‐two rats were parabiotically coupled to test regeneration of the sciatic nerve of the “donor” rat in the denervated gastrocnemius of the “host.”.

Proliferation of the implanted nerve was clearly demonstrated after 30 days. Histological and histochemical study revealed the formation of motor end‐plates of increasing complexity and after survival of 300 days mature motor end‐plates were observed. The electrophysiological study demonstrated that the muscle responded to stimulation of the nerve with normal stimulus. The immunological interaction did not interfere with the formation of “functional” motor end‐plates and central nerve centers of the “donor” rat are capable of eliciting motor activity of the limb of the “host.”.
The development of sensory innervation in the mouth and pharynx of the albino norway rat (mus norvegicus albinus)
Authors: Hogg Ira D. , Bryant James W.
Published: December 2004

In 7 mm rat embryos some sensory fibers from the four cranial nerves that innervate the mouth, pharynx and larynx have grown almost into contact with the basement membrane of the epithelium. Such fibers become more numerous but stay below it until the fetus has reached the twentieth day of gestation. At 25 mm C. R., or on the twentieth day, some fibers grow into the epithelium. Some are branched and some terminate in a Merkel's disc. By that time all types of lingual papillae can be recognized, but taste buds have not formed.

Nerve endings begin to appear at about the same time in the tongue, oral surface of the palate, and oral mucosa of the cheeks and lips. Taste buds are said to appear at about the time of birth. No functional bud was found at 36 mm C. R.

Intraepithelial nerve terminals have been found in the mouth at about the eighteenth day (20 mm). Other investigators have shown that rat embryos of 15.5 days can respond to the stroke of a hair across the snout by a lateral movement of the head and at 19 days can protrude the tongue independently of other movements. No record has been found concerning the age at which swallowing first occurs in the rat. It seems evident that some fibers can be stimulated at about the time they touch the basement membrane and before any recognized receptor has formed.
A quantitative analysis of the normal neuron population of the hypothalamic magnocellular nuclei in man and of their projections to the neurohypophysis
Authors: Morton Allan
Published: December 2004

The supraoptic nucleus in man extends throughout the greater length of the hypothalamus and most of it is retrochiasmatic in location. It contains an average of 75,500 neurons, of which about two‐thirds are in its dorsolateral portion (SON‐dl) and one‐third in its combined dorsomedial and ventromedial portions. The average density of neurons in SON‐dl is 15,300 per mm3 and, unlike neuron frequency, is remarkably constant from specimen to specimen. The paraventricular nucleus has an average of 55,500 magnocellular neurons.

In patients surviving one year or longer after hypophysectomy, there is retrograde loss of over 80% of neurons in both the supraoptic and paraventricular nuclei. Neuron loss occurs uniformly thrughout the length of each nucleus. Density decrease in SON‐dl is almost exactly proportional to decrease in neuron frequency.

It is concluded from these observations that most of the neurons throughout the entire extent of both the supraoptic and paraventricular nuclei in man project to the posterior lobe of the neurohypophysis and that there are over 200,000 fibers in the hypophysial stalk.
The development of the trigeminal nerve in baboon embryos (Papio sp.)
Authors: Gasser Raymond F. , Hendrickx Andrew G.
Published: December 2004

The arrangement of the trigeminal nerve or its primordium was studied in 27 baboon embryos and fetuses 2.5–63.0 mm (crown‐rump length), 24–64 days insemination age. The head region of seven representative specimens was reconstructed graphically or with wax. The entire extramedullary part of the nerve, including the related parasympathetic ganglia, was traced microscopically in serial sections stained with either hematoxylin and eosin or protargol‐S and eosin.

The crest is first apparent in five somite embryos (24 days) and becomes more prominent and extends farther ventrally by eight somites (25 days). Lateral and ventral to the crest the ectoderm shows a slight, gradual thickening but not as a distinct placode. At 11–19 somites (25–27 days) the primordium is a column of cells that becomes loosely arranged as it terminates in the first arch. By 21–22 somites (28 days) the enlarged primordium has the three divisions with the mandibular being most prominent and closely applied to ectoderm near the first groove. Between 26 and 36 somites (29–30 days) the trigemial ganglion and motor root become apparent. The distal part of each division is eosinophilic and fibrous. Branches from each division begin to form as sprays of fibers by 6.9–9.0 mm (32–33 days) and the primordia of the four related parasympathetic ganglia become evident. Many of the definitive branches and their communications with other nerves are present at 11.6–16.5 mm (36–40 days). Most of the branches and many communications with the facial nerve are established by 18.3–36.0 mm (45–54 days). All of the named branches, including the meningeal branches, are present at 63 mm (64 days).
Quantitative studies on the postnatal growth of the spinal cord and the vertebral column of the albino mouse
Authors: Sakla Francois B.
Published: December 2004

The rate of growth of the various regions of the spinal cord and the vertebral column of the albino mouse aged, 1, 10, 20, 30 and 120 days was studied. It was found that:

There is more rapid growth in the length of the vertebral column than that of the spinal cord. The lower regions of the vertebral column grow more rapidly than the upper regions but the reverse was found in the spinal cord resulting in regression of the spinal cord. The cord ends at one day opposite the fifth sacral vertebra and then receded to the fifth lumbar vertebra till 120 days.

The white matter has a more rapid rate of growth in volume than the gray matter. So the process of myelination and the growth of the fibers in diameter exceed the rate of growth of the neurons and their dendrites.

The packing density of the neurons is nearly the same in all regions of the cord with the exception of the cervical region which showed less packing density due to more branching of their dendrites.

The total number of neurons at each region is fixed from birth till maturity. The thoracic region contains the highest number of neurons followed by the cervical then the lumbar and the least number is in the sacral region.
Observations on the organization of the dendritic processes and receptor terminations in the abdominal muscle receptor organ of homarus
Authors: Nadol Joseph B. , Darin de Lorenzo A. J.
Published: December 2004

The dendritic processes and terminals of the abdominal muscle receptor organ of the lobster have been studied with the electron microscope. In both the “fast” and “slow” adapting components of the muscle receptor organ, dendritic processes ramify within the body of the stretch muscle in a zone of “relative muscle exclusion,” where the continuity of the muscle bundle is interrupted by a zone of connective tissue. The cell bodies and larger dendritic processes are ensheathed in alternate layers of connective tissue and Schwann cells, but the smallest dendritic twigs are entirely divested of their Schwann cell envelope. The membrane of the dendritic terminations is intimately applied to either connective tissue of the zone of relative muscle exclusion or to the sarcolemma of the stretch muscle. This apposition is interpreted as morphological specialization for transduction or mechanoelectric conversion. It is suggested that these two types of dendritic terminals may represent two distinct sites for transduction and may also mediate different modalities of input.

The distribution of dendritic processes and terminals differs in the fast and slow systems. In the fast system the dendrites quickly ramify into a glomerular burst of processes near the junction of stretch muscle and connective tissue. In the slow system, the dendrites ramify more gradually and lie more nearly parallel to the long axis of the stretch muscle.

In both the fast and slow systems, but especially in the dendritic terminals of the fast neuron, collections of vesicles 400–2000 Å in diameter have been observed. These vesicles are clearly different in fine structure from those found in the neuromuscular junction or axo‐dendritic synapses.

An effort is made to relate neurophysiological characteristics of this system with the fine structural observations, with particular attention to the mechanism of transduction, or mechanoelectric conversion.
Embryogenesis of the inferior olivary nucleus in the rat: A radioautographic study and a re‐evaluation of the rhombic lip
Authors: Ellenberger Carl , Hanaway Joseph , Netsky Martin G.
Published: December 2004

Interkinetic nuclear migrations studied by redioautography in the medullar neuroepithelium of the 14‐day rat embryo are similar to those in other areas of the neuraxis in other species. The cell cycle lasts approximately 12 hours. Olivary neurons are produced along the length of the alar plate on embryonic days 14 and 15, mostly on day 14. Between 36 and 48 hours after injection of thymidine‐ H3, labeled cells migrate into the mantle layer and are more concentrated in the alar lamina than in the basal lamina. The olivary primordium appears in the ventromedial medulla on day 17 and is almost mature by day 21. Labeled neurons in the alar lamina migrate to the primordium in two bands, the marginal and the submarginal migration strands. From these strands, labeled cells move into the ventrolateral and ventromedial portions of the olivary complex, Newly arrived neurons push the existing cells dorsally. By embryonic day 21, as proliferation of cells in the neuroepithelium ceases, the migration strands disappear, and the olive in fully formed.

In the series injected on day 14, heavily labeled neurons become located dorsally in the medial accessory, dorsal accessory and principal nucleus; lightly labeled cells are found in the ventral half of the complex. In the series injected on day 15, labeled cells are found only in the ventral portions of the olive, in the medial accessory nucleus.

His described 2 rhombic lips. The first may be an artifact. The second is not seen in the medulla of the rat. If the term is used for any species, it is best viewed as the lateral part of the alar plate.
The projection of the acoustic nerve to the ventral cochlear nucleus of the rat. A Golgi study
Authors: Feldman Martin L. , Harrison J. M.
Published: December 2004

Acoustic nerve fibers, stained by the rapid Golgi method, were observed to bifurcate, after entering the ventral cochlear nucleus, into an ascending and a descending branch. Each branch was composed of fibers running parallel to each other with very little overlap. Prior to bifurcating, the acoustic nerve fibers gave rise to collaterals which ramified in the region of the bifurcations. Ascending branch fibers terminated in bulbs of Held and bore from zero to five additional collateral endings, including bulbs of Held. Descending, branch fibers gave rise within the posterior ventral cochlear nucleus to from zero to five collateral endings. These included large endings identified as bulbs of Held. Ascending and descending branch collaterals did not extend beyond 40–50 μ from their paret axons. Descending branch fibers projected into the dorsal cochlear nucleus. The area of the ventral cochlear nucleus dorsal to the region of bifurcations was innervated in a unique manner. This innervation occurred via long dorsally running collaterals arising from the most dorsal fibers of the ascending and descending branch projections.

The data suggest morphological correlates of certain neurophysiological and behavioral findings in the areas of auditory localization and discrimination.
Fine structural studies of the main sensory trigeminal nucleus in the cat and rat
Authors: Gobel Stephen , Dubner Ronald
Published: December 2004

This study describes some of the fine structural features of the neurons and synaptic connections in the main sensory trigeminal nucleus at the level of the motor trigeminal nucleus. The dendritic spread of some neurons spans more than half with width of the nucleus. Primary dendrites arise either from main stem dendrites or directly from the cell body and divide at acute or right angles ito long secondary dendrites. The primary trigeminal afferent fibers form numerous large boutons en passant. These large central boutons are often surrounded by large spines, the shafts of secondary dendrites and small peripheral boutons. Such groupings of axonal and dendritic processes make up the trigeminal glomeruli. Within these glomeruli axo axonic synapses occur (1) between adjacent outer surfaces of central and peripheral boutons, (2) on evaginations of central boutons which project into peripheral boutons, and (3) on evaginations of peripheral boutons which project into central boutons. The trigeminal central boutons also synapse on primary dendrites, main stem dendrites and on cell bodies.
Efferent projections of the superior colliculus in the opossum
Authors: Rafols Jose A. , Matzke Howard A.
Published: December 2004

The Fink and Heimer technique was used to study the ascending and descending fiber degenerations resulting from unilateral electrolytic lesions in the superior colliculus of sixteen adult opossums. The ascending fiber degeneration left the colliculus by way of a small parabrachial bundle or with the brachium of the superior colliculus. The former bundle contributed degenerating terminals to the suprageniculate, parabrachial, and magnocellular medial geniculate nuclei and appeared to terminate in the lateral terminal nucleus of Hayhow (Hayhow, '66). The latter bundle contributed fibers to the pretectal and posterolateral nuclei as well as discrete projections to the ventral lateral geniculate nucleus and ventral thalamus.

Descending degenerating fibers in the brainstem were destributed along three tracts: (1) a medial predorsal bundle, (2) an intermediate tectoreticular, and (3) a lateral tectopontine. These tracts were seen to terminate mainly in tegmental and reticular centers as well as in the lateral basilar nucleus of the pons. Degenerating fibers of the predorsal bundle were followed to lower medullary levels but could not be traced to spinal levels.

The present findings are descussed in relation to data reported for more developed mammalian species.
Subcortical projection of the magnocellular medial geniculate body of monkey
Authors: Locke Simeon
Published: December 2004

Subcortical projection of the magnocellular medial geniculate body to the lateral segment of the globus pallidus is suggested on the basis of anatomical observations in six Macaca mulatta. In two, extensive decortication failed to produce complete degeneration of the magnocellular division of the nucleus, suggesting the existence of a subcortical projection as well. In four other monkeys, lesions in the globus pallidus produced varying degrees of nerve cell loss with associated gliosis in the magnocellular medial geniculate nucleus. The suggestion is offered that this nucleus is an area of thalamic representation of vestibular function which projects to globus pallidus and vestibular cortex.
Neocortical projections to the pons and medulla of the nine‐banded armadillo (Dasypus novemcinctus)
Authors: Harting John K. , Martin George F.
Published: December 2004

The pattern of neocortical projections to the pons and medulla was determined by employing the Nauta‐Gygax technique ('54) on the brains of armadillos subjected to neocortical ablations. The results of this study indicate that the pretrigeminal basilar pontine gray receives input from a considerable portion of the neocortex. Degenerating fibers resulting from a lesion of the frontal tip of the neocortex terminated within the dorsal medial, the medial and the ventral medial areas of the rostral basilar pontine gray. Corticopontine fibers from the mid‐presupraorbital neocortex ended throughout the rostral to caudal extent of the basilar pontine gray, and terminated within the dorsal medial, the medial and the ventral medial areas; whereas degenerating fibers resulting from a lesion of the neocortex immediately rostral to the supraorbital sulcus terminated within the medial, the ventral and the ventral lateral areas of the basilar pontine gray. The neocortex immediately caudal to the supraorbital sulcus distributed corticopontine fibers to the ventral, the ventral lateral, the dorsal lateral and to the dorsal areas of the basilar pontine gray, while degenerating fibers resulting from lesions of the caudal one‐third and most caudal tip of the neocortex projected to the ventral and lateral portions of the basilar pontine gray.

Neocortical projections to the pontine and medullary reticular formation originated mainly from cortical areas rostral and immediately caudal to the supraorbital sulcus. The neocortex rostral to the supraorbital sulcus distributed to the rostral and medial portions of the pontine reticular formation, whereas corticoreticular fibers from the neocortex immediately caudal to the suprarbital sulcus, also distributed degenerating fascicles to the spinal trigeminal nucleus, the nucleus of the solitary tract and to the nucleus cuneatus. No degenerating fibers were seen to terminate within motor nuclei of cranial nerves located within either the pons or medulla.
Quantitative delineation of the efferent anatomy of the medial mammillary nucleus of the cat
Authors: Fry William J.
Published: December 2004

A quantitative description based on fractional parts of the total neuron population discovered for the projecting neuron subpopulations of the medial mammillary nucleus in the cat is presented. Five neuron subpopulations send projections through the principal mammillary tract to the thalamic, subthalamic and tegmental structures and one intrinsic subpopulation has been identified. These subpopulations describe in detail the structural organization of the projecting neurons. Although the methodology and supportive research leading to these results is quite extensive the material presented in this paper is concerned with 15 cats in which appropriate lesions have been placed. These animals provide the data upon which the quantative description rests.
The dendritic tree of spinal neurons
Authors: Gelfan Samuel , Kao Grace , Ruchkin Daniel S.
Published: December 2004

The size of the dendritic tree was determined from the number, length and diameter of primary dendrites and number and length of their branches in 360 unselected neurons from all areas of the spinal gray of L7 segment in Golgi‐Kopsch preparations (dog). A direct proportionality was demonstrated between the size of the dendritic tree of a neuron and the number of its primary dendrites; a basic dependence of the entire dendritic complex upon the number of initial dendrite extensions from cell body. The existence of two dendrite parameter levels, and consequently two size levels of the whole dendritic tree, was also established; one for the large neurons and one for the small ones. The parameter and tree size differences between the two classes of neurons, the latter distinguished by different cell body‐size ranges, were all statistically highly significant. Very little of the variability of the parameters or of the whole tree could be accounted for by the variability of the specific cell body‐size within each of the two groups of neurons or within the entire sample. The morphological distinction is between two classes of neurons. The mean dendrite surface area for the entire population sample of large neurons was some five times greater than the mean for the small ones. With commensurate cell body‐size differences, and thus total receptive surface area, this implies a 5‐fold difference in mean number of synaptic contacts/neuron. The evidence, in addition, strongly pointed to motoneurons as having larger dendritic trees, on the average, than interneurons with comparably‐sized cell bodies. It was previously estimated that only 2% of interneurons in L7 segment, which outnumber motoneurons 30:1, are large cells.
The differential effects of unilateral lid closure upon the monocular and binocular segments of the dorsal lateral geniculate nucleus in the cat
Authors: Guillery R. W. , Stelzner D. J.
Published: December 2004

One eyelid has been sutured in each of three seven‐day old kittens. Three months later the brains were fixed and stained by the Nissl method. In the contralateral lateral geniculate nucleus the cells of the deprived lamina A were smaller, more closely packed and paler staining than those in the normally innervated, ipsilateral lamina A. However, these changes were seen in the medial parts of the contralateral lamina A only. The lateral parts, which extend beyond the border of lamina A1 and which project to the monocular parts of the visual cortex showed no change. These results show that some geniculate cells are not affected by deprivation. The observations are consistent with the view that during normal development geniculate cell axons from adjacent laminae compete with each other for synaptic surfaces upon binocular cortical neurons: that unilateral lid suture upsets the balance of this competition and that the reduced perikaryal growth in the lateral geniculate nucleus is secondary to the unbalanced axonal development, which occurs in the binocular portions of the geniculocortical projection but which cannot occur in the monocular portions, where there is no competition.
The effects of Wulst ablations on color, brightness and pattern discrimination in pigeons (Columba livia)
Authors: Pritz Michael B. , Mead William R. , Northcutt R. Glenn
Published: December 2004

Pigeons were trained to peck at a transparent response key on which was projected either a color, brightness or pattern discrimination problem. Each subject was trained on only one of these problems. Training was continued until the subjects had reached asymptote. After reaching asymptote, subjects received brain ablations (by subpial suction) according to the following design: hyperstriate group, tissue removed from the Wulst; ablated controls, tissue removed from the neostriatum and corticoid areas; operated controls, no neural tissue intentionally removed. After a two week recovery period, each subject was re‐tested on the same discrimination task that it had learned pre‐operatively. Those birds with ablations of the Wulst showed deficits in performance on the brightness and pattern problems, but not on the color problem. Ablated and control subjects showed no post‐operative deficits. These findings indicate that the Wulst functions in brightness and pattern discrimination, but may not be essential for color discrimination.
Accessory oculomotor nuclei in the monkey: Projections and effects of discrete lesions
Authors: Carpenter Malcolm B. , Harbison John W. , Peter Philip
Published: December 2004

A study in the monkey was made of the degeneration and effects of lesions in the accessory oculomotor nuclei. Lesions destroyed: (1) the interstitial nucleus (INC), (2) regions lateral and dorsal to the INC, (3) the posterior commissure (PC), and (4) the central gray. Degeneration was studied in Nauta‐Gygax stained sections.

Efferent fibers from the INC project: (1) contralaterally, to specific subdivisions of the oculomotor complex (OMC), (2) bilaterally, to the trochlear nuclei (TN), and (3) ipsilaterally, to the medial vestibular nucleus, to certain perihypoglossal nuclei and to the spinal cord. Projections of the INC to the oculomotor complex cross in ventral parts of the PC and project differentially to the dorsal, medial and intermediate cell columns via the contralateral INC and MLF. No fibers from the INC project to the ventral somatic cell columns, the visceral nuclei or the caudal central nucleus of the OMC. Discrete lesions in the INC produce transient head tilt to the opposite side.

Unilateral and bilateral lesions of the PC interrupt crossing interstitio‐oculomotor fibers and produce: (1) symmetrical differential degeneration in the OMC and TN similar to that resulting from discrete lesions of the INC, (2) bilateral eyelid retraction, and (3) impairment of vertical gaze, particularly upward gaze. Horizontal gaze and pupillary reflexes were normal.

Evidence suggests that relationships between interstitio‐oculomotor fibers and the nuclei of the posterior commissure may underlie neural mechanisms that regulate vertical eye movements.
Axonal bifurcation in the dorsal root ganglion of the cat: A light and electron microscopic study
Authors: Ha Hongchien
Published: December 2004

Bifurcation of the axon of unipolar neurons in the dorsal root ganglion of the cat has been studied by light and electron microscopy.

Osmic acid, Golgi and silver preparations have revealed two types of bifurcation: (1) of myelinated fibers characterized by constriction at the nodal region with peripheral and central branches of equal diameter; (2) of small fibers characterized by a broad triangular expansion at the junctional region with a much thicker peripheral as compared to the central branch. These differences in bifurcation of unmyelinated and myelinated axons can be related to the velocity of conduction in the peripheral nerve and dorsal roots.

The ultrastructure of the nodal region at the bifurcation resembles the node of Ranvier of a peripheral nerve fiber. The node of Ranvier at the bifurcation consists of three cells of Schwann and adjacent cells are closely apposed and interdigitated.

Neurofilaments and microtubules are prominent structures within the axoplasm at the nodal regions. They group into two streams as the unipolar process bifurcates, entering the peripheral and central branch respectively. At the junctional region within the axoplasm, numerous mitochondria and scattered multivesicular bodies are always observed.