bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pentylated organotin standards: Guidelines for their synthesis, purity control and quantification
Authors: Dirkx W. M. R. , Adams F. C. 
Published: January 2005

AbstractPentylated derivatives of six environmentally important organotin compounds were obtained by using a Grignard derivatization. The purity of these pentylated calibrants was checked by gas chromatography–quartz furnace atomic absorption spectrometry (GC QFAA) and gas chromatography–mass spectrometry ion‐trap detection (GC MS‐ITD). Through combination of the total tin contents of every pentylated organotin standard, obtained after wet acid destruction of 0.5 ml of the respective calibrant, and the species composition or impurities present in the same standard, a well‐defined pentylated organotin standard was obtained which could be used to calibrate GC QFAA and GC atomic emission detection (AED) systems.In a similar way aqueous organotin standards can be obtained, which can be used in spiking experiments to verify the recovery efficiency of a developed analytical extraction procedure for organotins.
Polygermoxanes suitable for biochemical purposes: II Linear trigermoxanes (high‐viscosity oils)
Authors: Duverneuil Gilles , Mazerolles Pierre , Perrier Elisabeth 
Published: January 2005

AbstractLinear trigermoxanes, R1 RGeOGe(R3)2OGeRR1, a new series of organogermanium compounds, were synthesized by reaction of a lithium organogermanolate with a suitable organogermanium dihalide. With alkyl or phenyl substituents, these trigermoxanes are structurally unstable viscous oils, due to redistribution reactions. When R3 substituents are bulky groups, such as mesityl, trigermoxanes are thermally and structurally stable oils; depending on the R1 and R2 substituents their viscosities lie in the range 240 to more than 1500 cPo (mPa s) at 20°C. When both terminal germanium atoms are substituted with two mesityl groups, trigermoxanes are stable glassy solids.
Determination of organotin compounds in marine sediments using graphite furnace atomic absorption spectrometry
Authors: Mortensen Gitte , Pedersen Britta , Pritzl Gunnar 
Published: January 2005

AbstractOrganotin compounds, especially tributyltin, began to cause concern 10 years ago due to a high toxicity towards marine organisms. Several methods of analysing organotin compounds in various matrices have already been developed to determine organotin species simultaneously, but these are quite expensive as special equipment and specialized staff are needed. A simple screening method, which determines the organic tin compounds in the sediment, has therefore been developed and validated. The method can easily be implemented in laboratories accustomed to tracelement analyses; the sediment is extracted by a two‐phase extraction and the organic extract is analysed using graphite furnace atomic absorption spectrometry (GF AA.) The screening method has been validated using high‐pressure liquid chromatography‐inductively coupled plasma mass spectrometry (HPLC–ICP MS).
Arsenobetaine as the major arsenic compound in the muscle of two species of freshwater fish
Authors: Shiomi Kazuo , Sugiyama Yasuo , Shimakura Kuniyoshi , Nagashima Yuji 
Published: January 2005

AbstractThe chemical form of arsenic contained in the muscle of certain freshwater fish was examined using cultured specimens of rainbow trout (Salmo gairdneri) and wild specimens of Japanese smelt (Hypomesus nipponensis). More than 95% of the total arsenic of both species was extracted with methanol and recovered in the water‐soluble fraction. The major arsenic compound of both species was purified by cation‐exchange chromatography on Dowex 50, gel filtration on Bio‐Gel P‐2 and HPLC on Asahipak GS‐220H. Behavior in the above purification procedure and analyses of the purified compounds by HPLC–ICP and TLC confirmed that the major arsenic compound of both species was arsenobetaine. Arsenobetaine found in cultured rainbow trout seems to be derived from the commercial assorted feed containing arsenobetaine as the major arsenical. On the other hand, the result with wild Japanese smelt suggested that arsenobetaine is a naturally occurring compound in the freshwater environment.
Fungicidal, bactericidal and antifertility activities of diorganosilicon(IV) complexes derived from benzothiazolines
Authors: Kumari A. , Singh I. , Tandon J. P. 
Published: January 2005

AbstractSynthetic, structural and biological aspects of trigonal‐bipyramidal, Me2S(N—S)CI and octahedral, Me2Si(N—S)2 types of diorganosilicon(IV) complexes of heterocyclic benzothiazolines (N—SH) are described. The complexes were characterized by elemental analysis, molecular weight determination, conductance measurements and electronic, infrared, 1H and 13C NMR spectroscopic studies. Some ligands and their corresponding dimethylsilicon(IV) complexes have been tested for their effects on several pathogenic fungi and bacteria and found to be quite active in this respect. Antifertility activity in male mice of some representative ligands and their silicon complexes was also evaluated and discussed.
Selenium speciation by high‐performance liquid chromatography with on‐line detection by atomic absorption spectrometry
Authors: Lei Tian , Marshall W. D. 
Published: January 2005

AbstractSeveral approaches to the determination of selenomethionine, selenocystine, selenite and selenate by high‐performance liquid chromatography with online detection by atomic absorption spectrometry are described. The N−2,4‐dinitrophenyl derivatives of selenomethionine, selenoethionine, selenocystine and phenylmercury(II) cystineselenoate were recovered from aqueous solution, separated on a Nucleosil 5‐NO2 reversed‐phase HPLC column with a methanolic mobile phase containing acetic acid and triethylamine, and detected with a quartz thermochemical hydride‐generating interface–atomic absorption spectrometry (AA) system. The restriction of having to perform chromatography with an organic mobile phase (to support the combusion process) was overcome with a new interface design capable of operation with either organic or aqueous HPLC mobile phases. Using aqueous acetic acid (0.015% v/v) containing 0.1% (w/v) ammonium acetate delivered at 0.5cm3 min−1, selenate, selenite, selenomethionine, selenocystine and selenoethionine were separated virtually to baseline on a cyanopropyl‐bonded phase HPLC column. Other selenium compounds which were investigated included methane seleninic and methane selenonic acids as well as the crude oxidation product mixtures resulting from the treatment of selenomethionine and selenocystine with hydrogen peroxide. A procedure for extracting selenate, selenite, selenomethionine, selenocystine and selenoethionine from spiked water or ground feed supplement into liquefied phenol resulted in acceptable recoveries for the latter four analytes but was unacceptably low for selenate.
Di(n‐butyl)tin bis(dihydroxybenzoate)s: Synthesis, spectroscopic characterization and in vitro antitumour activity
Authors: Gielen Marcel , Bouhdid Abdeslam , Kayser Françcois , Biesemans Monique , Willem Rudolph , De Vos Dick , Mahieu Bernard 
Published: January 2005

AbstractSix di(n‐butyl)tin(IV) and two dimethyltin(IV) bis‐(dihydroxybenzoate)s were synthesized and characterized by 1H, 13C and 119Sn NMR and Mössbauer spectroscopy. Five of the di(n‐butyl)tin compounds were screened in vitro against six human tumour cell lines, MCF‐7, EVSA‐T, WiDr, IGROV, M19 and A498. They are more active than carboplatin, cisplatin and 5‐fluorouracil against all cell lines and of comparable activity or better than methotrexate. All dihydroxybenzoates with an ortho‐bydroxyl group are more active against MCF‐7 cells than substituted salicylates screened previously.
Reagent control of stereochemistry in allylic additions to chiral aldehydes with CpMo(NO)(X)(2‐methallyl) complexes of high enantiomeric purity
Authors: Faller J. W. , Nguyen Jenna Thu , Mazzieri Maria R. 
Published: January 2005

AbstractReactions of (R)‐ and (S)‐CpMo(NO)(η3‐methallyl)X(X=camphorsulfonate, Cl, Br, I) with chiral α‐substituted aldehydes yield homoallylic alcohols with high diastereoselectivity. Reactions of (R)‐ and (S)‐CpMo(NO)(η3‐ methallyl)L S[LS = (IS)‐(+)‐10‐camphorsulfonate] with D‐glyceraldehyde acetonide yield the corresponding homoallylic alcohols in >98% diastereomeric excess. Reactions with racemic 2‐phenyl‐propionaldehyde and nonracemic 3‐benzyloxy‐2‐methylpropanol are also considered and show that there is very high reagent control of stereo‐chemistry in additions to the carbonyl group.
η‐Cu3Si percentage and particle size in various rochow contact masses
Authors: Lieske H. , Fichtner H. , Kretzschmar U. , Zimmermann R. 
Published: January 2005

AbstractVarious Rochow contact masses have been characterized by catalytic tests as well as by X‐ray diffraction with respect to η‐Cu3Si percentage and particle size. The presence of η‐Cu3Si in the contact masses is neither a necessary nor a sufficient precondition of catalytic activity, but a certain contribution of dispersed η‐Cu3Si to the activity cannot be excluded. The results can be explained consistently by assuming highly dispersed or even two‐dimensional Cu‐Si species, not detectable by X‐rays, as catalytically active species. The promoters zinc, antimony and tin do not significantly change the percentage and particle size of η‐Cu3Si.
Breakage of λ‐DNA by inorganic tin and organotin compounds as environmental pollutants
Authors: Hamasaki Tetsuo , Sato Takahiko , Nagase Hisamitsu , Kito Hideaki 
Published: January 2005

AbstractIn proportion to the environmental pollution problems caused by organotin compounds, the genotoxicities of tin compounds in the environments have become of interest so as to estimate their safety in recent years. In this work, isolated λ‐DNA (double‐strand DNA) was incubated with inorganic tin(II) and tin(IV) and five organotin compounds [n‐butyltin trichloride, di(n‐butyltin) dichloride, methyltin trichloride, dimethyltin dichloride and trimethyltin chloride] in reaction systems both with and without hydrogen peroxide (H2O2) content. The tin compounds tested in this study did not induce DNA breakage in the absence of hydrogen peroxide. Divalent inorganic tin (SnCl2) and tetravalent inorganic tin (SnCl4) caused DNA breakage in the presence of hydrogen peroxide (10 mM), and the DNA damage activity of inorganic tin was much more potent in divalent inorganic tin (SnCl2) than in tetravalent inorganic tin (SnCl4). Divalent inorganic tin (SnCl2) induced DNA breakage in a concentration‐dependent fashion at concentrations greater than 0.1 mM of SnCl2 in the presence of hydrogen peroxide (10 mM). DNA breakage was not caused by n‐butyltin compounds and methyltin compounds either in the presence or in the absence of hydrogen peroxide.
A new procedure for the speciation of mercury in water based on the transformation of mercury (II) and methylmercury (II) into stable acetylides followed by HPLC analysis
Authors: Fabbri Daniele , Vassura Ivano , Lombardo Marco , Trombini Claudio 
Published: January 2005

AbstractConversion of mercury(II) and methylmercury(II) species dissolved in water into di(phenylethynyl)mercury and methyl(phenylethynyl) mercury takes place in satisfactory yield under alkaline conditions by stirring the aqueous solution with phenylacetylene at room temperature. Mercury speciation is simply obtained by HPLC analysis of the two organometallic species. The presence of heavy metals such as copper(II), zinc(II), cadmium(II) and lead(II) in concentrations 10000 times higher than mercury is tolerated, while little interference is displayed by humic acids and cysteine. Seawater samples can also be analysed following a properly adapted procedure.
Programming life histories: An experimental design and initial results
Authors: Denenberg Victor H. , Karas George G. , Rosenberg Kenneth M. , Schell Stephen F. 
Published: January 2005

AbstractThe life experiences of rats were experimentally programmed through the systematic manipulation of several social and stress variables. These were (1) infantile handling vs. no handling of the mothers of the subjects, (2) infantile handling vs. no handling of the subjects, (3)rearing of the subjects in either a maternity cage or a free environment between birth and weaning, (4) rearing of the subjects in either a laboratory cage or a free environment between weaning and 42 days of age, and (5) presence or absence of a stress experience (shuttlebox avoidance learning at 70 days of age, or food and water deprivation at 100 days) in adulthood. Test measures included open‐field performance and shuttlebox learning at 70 and 190 days of age.Open‐field activity was increased by handling pups in infancy and by rearing pups in a free environment between birth and weaning, whereas it was decreased by food and water deprivation at 100 days. Postweaning free‐environment experience improved avoidance learning performance. A number of interactions were significant, most of which involved the three preweaning variables of Mother Handling, Offspring Handling, and Preweaning Housing.
Relationship of age at eye opening to first optokinetic response in deermice (Peromyscus)
Authors: Vestal Bedford M. , King John A. 
Published: January 2005

AbstractThe relationship between visual development and age at eyelid separation was studied in three stocks of Peromyscus maniculatus bairdi, two stocks of P.m. gracilis, P. polionotus, and P. eremicus. The maniculatus subspecies had each been selectively bred for early and late age at eye opening. Mice were tested in a transparent chamber suspended within a rotating drum, which was lined with alternating 3/4‐in. black and white vertical stripes. Beginning within 8 hr of eye opening, each mouse was given 5, 15 sec trials daily, until it responded. Criterion of vision was an optokinetic response in 2 of the 5 trials. Of 75 mice tested, only the early eye opening selected line of P. m. bairdi failed to respond on the day of eye opening. The results indicate that Peromyscus can see conspicuous environmental features at the age of eyelid separation. The delayed optokinetic response in the early selected bairdi line, requiring an average of 2.4 additional days of maturation, indicates the genetic independence of eyelid separation and visual development. The same line did not respond significantly earlier than wild type bairdi, indicating that the extra visual experience afforded by early eye opening did not increase the rate of maturation of the system (s) governing the optokinetic response.
The development of visually evoked electrocortical responses in the rat
Authors: Rose Guenter H. 
Published: January 2005

AbstractThe development of electrocortical responses evoked by brief, focused monocular light stimulation was studied in 35 lightly anesthetized albino rat pups (Sprague‐Dawley strain) between birth and 35 days of age. A definite sequence of waveform changes occurred during maturation. The initial response at 10 to 11 days of age consisted of a long latency, negative wave. Subsequently, at approximately 12 days of age, a shorter latency, positive‐negative complex appeared. The initial, long latency, negative wave decreased rapidly in latency over the next few days until it coalesced with the negative component of the shorter latency, positive‐negative complex at about 15 days of age, resulting in a biphasic positive‐negative wave similar to that recordable in the adult rat. These results are compared and contrasted with a similar sequence observed in the developing kitten, and are discussed in terms of structural, electrophsiological, and behavioral maturation.
Age differences in central nervous effects of visual deprivation in the dog
Authors: Fox M. W. , Inman O. , Glisson S. 
Published: January 2005

AbstractVisual deprivation in dogs during the first 5 weeks of life resulted in marked structural, biochemical, and electrophysiological changes which were not apparent in dogs similarly treated between 5 and 10 weeks of age or for 5 weeks as adults. These findings are discussed in relation to the period of integration, when structuro‐functional relationships of neural elements begin to reach adult‐like levels of organization. It was postulated that lack of stimulation of a sensory modality during this period would result in arrested development of the system so treated. This hypothesis was partially supported; although there was complete visual deprivation, some neuronal and myelin development occurred independent of visual stimulation. Visual evoked potentials were markedly abnormal in the youngest age group only. The findings suggest a “sensitive” period in the pathodevelopmental sense; development of a particular system is retarded if stimulation is inadequate. This period corresponds to the period of integration when structuro‐functional organization of component systems of the central nervous system occurs.
Maturation and topography of the auditory evoked response of the prematurely born infant
Authors: Weitzman Elliot D. , Graziani Leonard J. 
Published: January 2005

AbstractThe behavioral, EEG, and auditory responses have been studied during the maturation of prematurely born infants. It was found that: (1) The less mature the infant, the less time spent in a quiet sleep state. As the infants matured, periods of quiet sleep occurred for longer durations and interrupted the active sleep phase more frequently. (2) The EEG pattern of young infants (23–26 weeks estimated conceptional age [ECA]) consisted almost entirely of an “intermittent” pattern. As maturation progressed, this “intermittent” pattern became more closely associated with periods of quiet sleep. The continuous pattern appearing at approximately 29 to 31 weeks (ECA) was increasingly associated with an active sleep phase; by 34 to 35 weeks (ECA), the correspondence between EEG pattern and sleep state was more constant. (3) All infants regardless of conceptional age responded to the auditory stimulus from all recorded areas of the scalp. A sequence of wave patterns of the auditory evoked response was noted as a function of maturation. The young infants had a large, negative, long‐latency (180–270 msec) wave diffusely over the scalp. As maturation progressed, a series of negative‐positive‐negative components was recognized. The evoked response patterns changed wave latency‐amplitude relation as a function of both age and scalp topography. (4) The latency of the evoked response waves N1 and P2 were consistently greater during the intermittent, compared to the continuous EEG pattern in infants 34 to 40 weeks age post conception. (5) A small, (early ∼ 15 msec) auditory evoked response was recorded from the ear electrode and is probably of muscle origin. This early muscle response was augmented when the baby was awake and crying, intermediate in amplitude during an active sleep period, and barely detectable or absent during quiet sleep.
Effects of maternal essential fatty‐acid deficiency on neonatal rat brain
Authors: Steinberg Alan B. , Clarke Gregory B. , Ramwell Peter W. 
Published: January 2005

AbstractFemale weanling rats were raised to sexual maturity on either a normal stock diet or an essential fatty‐acid (EFA) deficient diet, and then bred. Brain weight and lipid composition of the offspring from these animals were measured as part of an investigation into factors contributing to the early death of EFA‐deficient progeny. Lactation failure does not seem to be an adequate explanation of the early deaths since the dead EFA‐deficient offspring frequently have milk in their stomachs. Maternal behavior including nesting was lacking, however, in EFA‐deficient dams. The EFA‐deficient brains weighed less than normal neonatal brains, and frequently had subdural hemorrhaging. Relative to body weight, however, some “sparing” of the brain was apparent. Total brain sterol concentration was not measurably different, but fatty‐acid composition of total brain lipid and phospholipid was. The EFA‐deficient offspring had relatively less arachidonate and other EFA‐related fatty acids, while the proportion of trienoic acids, principally 20:3 and 22:3 was increased considerably. In phosphatidyl ethanolamine, the proportion of 16:0 was particularly elevated in the EFA‐deficient brains. The results are discussed in relation to the integrity of myelin and the synthesis of prostaglandins, as possible factors in the premature death of EFA‐deficient progeny.
Temperature reduction in neonatal mice: Effects on later behavior
Authors: Haggett Burton N. , Werboff Jack 
Published: January 2005

AbstractThe effects of body temperature reduction in neonatal C57BL/6J mice were studied in 2 experiments. Experiment I investigated the development of the thermoregulatory response of mice from 1 to 15 days of age in their nest and in an ambient environment of 22°C. The experimental conditions could then be specified to produce body temperature reduction of either 5 or 10°C for 10 min from day 1 through 15. In Experiment 2, effects of these body temperature reductions at day 1 to 5, 6 to 10, or 11 to 15 on subsequent behavior at 30 and 70 days of age were studied. Three control groups (handled, non‐temperature maintained; handled, temperature maintained; and nonhandled) were treated at the same age periods. Behavioral tests were open field, water runway, water maze (preference) and single‐alternation problem, and water submersion. No consistent behavioral effects could be attributed to body temperature reduction or to age at treatment in infancy. Mice receiving body temperature reduction of 5 and 10°C, or handling (with or without body temperature reduction) behaved differently from nontreated subjects on latency and activity measures in an open field; on the latency measure in the water maze (preference) test; on the errors and days to criterion measures in the single‐alternation water maze; and in time‐to‐submersion in water. The behavioral alterations of the treated groups could be interpreted to represent reduced emotionality, and improved performance and learning ability resulting from the neonatal experiences.
Stereotaxic atlas of the infant rat hypothalamus
Authors: Valenstein Thelma , Case Barbara , Valenstein Elliot S. 
Published: January 2005

AbstractA sterotaxic atlas of the hypothalamus of the 1‐, 7‐, and 14‐day‐old rat is presented. Ancillary techniques for anesthetizing these young animals, mounting the neonates in the instrument, and special histological considerations are discussed.
Partial interocular transfer of visual discriminations in cats
Authors: Schissler Dale R. , Riesen Austin H. 
Published: January 2005

AbstractNormally expected visual behavior in the cat, following monocular training, is a full stimulus equivalence when the second eye is used in transfer tests. This expectation has not been tested severely by using competing habits trained separately for each eye. Two groups of cats, normal and with striate cortex ablated, were tested under conditions of training in which opposing habits were used with the two eyes. Using intensity discrimination habits it was found that normal and operated cats failed to show complete interocular transfer. The normal group exhibited more transfer (greater conflict) from one eye to the other than did the operated group. It is suggested that interocular equivalence is partly dependent upon the organism's having learned to use similar kinds of visual cues with both eyes. The data also support the idea that encephalization increases binocularity and interocular equivalence.