bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upregulation of calretinin immunostaining in the ferret inferior colliculus after cochlear ablation
Authors: Fuentes‐Santamaria Verónica , Alvarado Juan Carlos , Brunso‐Bechtold Judy K. , Henkel Craig K. 
Published: April 2003

AbstractIn many systems, including ascending auditory pathways, calcium‐binding proteins are markers of specific neuronal circuits. Previous studies suggest that calretinin immunostaining may be a specific marker for circuits in the inferior colliculus (IC) that code timing information. We undertook experiments to determine the changes in calretinin immunostaining in the IC that take place in response to cochlear ablation. Cochlear ablation was performed unilaterally in ferrets just after hearing onset. Animals survived for 2–3 months after ablation and brains were then processed for calretinin immunocytochemistry. The mean optical density and stained area of the calretinin immunopositive plexus in the IC were determined for five coronal sections through the right and left IC. In controls (n = 3), measurements of these parameters in the central nucleus of the IC showed symmetry between the two sides. In experimental animals (n = 8) the calretinin immunopositive plexus contralateral to the cochlear ablation was denser and larger than that in either the ipsilateral IC or in the IC of control animals. The calretinin plexus in the ipsilateral IC was slightly less dense and smaller than in controls but the differences did not reach statistical significance. IC volume measurements and synaptophysin immunostaining analysis in the central nucleus of the IC revealed no statistical differences between ablated and control animals or between the two sides in ablated animals. The significant increase in both mean optical density and immunostained area of the calretinin plexus in the IC contralateral to the cochlear ablation may reflect an upregulation in calretinin expression in the nuclei that contribute to this plexus. J. Comp. Neurol. 460:585–596, 2003. © 2003 Wiley‐Liss, Inc.
Sexual differentiation of projections from the principal nucleus of the bed nuclei of the stria terminalis
Authors: Gu Guibao , Cornea Anda , Simerly Richard B. 
Published: April 2003

AbstractThe principal nucleus of the bed nuclei of the stria terminalis (BSTp) is sexually dimorphic and participates in several aspects of reproduction. A detailed analysis of its projections revealed that the BSTp provides major inputs to forebrain regions that are sexually dimorphic and contain high densities of neurons that express receptors for sex steroid hormones in a pattern that is remarkably similar to that of the medial amygdaloid nucleus. The BSTp sends its strongest outputs to the periventricular zone of the hypothalamus and innervates structures thought to play important roles in regulating hormone secretion from the anterior pituitary, but it also provides strong inputs to the medial preoptic and ventromedial nuclei of the hypothalamus. The BSTp also sends a strong return projection to the medial nucleus of the amygdala. The projections of the BSTp appear to be more robust in males with striking sex differences observed in most, but not all, major terminal fields. Moreover, various terminal fields appeared to differ in their developmental sensitivity to manipulation of circulating levels of sex steroids during the neonatal period. Thus, the organization of projections from the BSTp suggests that it plays a particularly important role in regulating neuroendocrine function and that neurons in this nucleus may relay olfactory information to the hypothalamus differently in male and female rats. Furthermore, the differential action of sex steroids on the density of afferents from the BSTp in various regions indicates that these hormones exert a target‐specific influence on the development of BSTp projections. J. Comp. Neurol. 460:542–562, 2003. © 2003 Wiley‐Liss, Inc.
Mercury minimization measures to meet total maximum daily load requirements
Authors: Pickard Brian C. 
Published: April 2003

AbstractMercury is a naturally occurring element that bioaccumulates due to its tendency to associate with organic
matter. Thus methylmercury, the organic (and most toxic) mercury form, will bioaccumulate up the food
chain, with the largest aquatic concentrations found in predatory fish. Five segments of the lower Savannah River
were listed on the state of Georgia's 2000 Section 303(d) list of impaired waters because mercury
in certain species of fish tissue exceeded fish consumption (the primary human route of exposure)
guidelines. Consequently, EPA developed a Total Maximum Daily Load (TMDL) for total mercury for the
middle/lower Savannah River. An Army installation, located in the affected watershed and identified as a
significant mercury contributor, was allowed a 7.43E‐06 kg/yr wasteload allocation (WLA) of
discharged mercury. In lieu of end‐of‐pipe sampling, the installation chose development and
implementation of a mercury minimization plan (MMP) for TMDL compliance. This article describes the
methodology used for MMP development and summarizes the policies, procedures, and guidelines used to reduce
and/or eliminate mercury‐containing discharges into the wastewater collection system. © 2003
Wiley Periodicals, Inc.
The role of RAD51 in etoposide (VP16) resistance in small cell lung cancer
Authors: Hansen Lasse Tengbjerg , Lundin Cecilia , Spang‐Thomsen Mogens , Petersen Lone Nørgård , Helleday Thomas 
Published: April 2003

AbstractEtoposide (VP16) is a potent inducer of DNA double‐strand breaks (DSBs) and is efficiently used in small cell lung cancer (SCLC) therapy. However, acquired VP16 resistance remains an important barrier to effective treatment. To understand the underlying mechanisms for VP16 resistance in SCLC, we investigated DSB repair and cellular VP16 sensitivity of SCLC cells. VP16 sensitivity and RAD51, DNA‐PKcs, topoisomerase IIα and P‐glycoprotein protein levels were determined in 17 SCLC cell lines. In order to unravel the role of RAD51 in VP16 resistance, we cloned the human RAD51 gene, transfected SCLC cells with RAD51 sense or antisense constructs and measured the VP16 resistance. Finally, we measured VP16‐induced DSBs in the 17 SCLC cell lines. Two cell lines exhibited a multidrug‐resistant phenotype. In the other SCLC cell lines, the cellular VP16 resistance was positively correlated with the RAD51 protein level. In addition, downregulation or overexpression of the RAD51 gene altered the VP16 sensitivity. Furthermore, the levels of the RAD51 and DNA‐PKcs proteins were related to VP16‐induced DSBs. The results suggest that repair of VP16‐induced DSBs is mediated through both RAD51‐dependent homologous recombination and DNA‐PKcs‐dependent nonhomologous end‐joining and may be a determinant of the variation in clinical treatment effect observed in human SCLC tumors of identical histologic subtype. Finally, we propose RAD51 as a potential target to improve VP16 efficacy and predict tumor resistance in the treatment of SCLC patients. © 2003 Wiley‐Liss, Inc.
Tumor‐localization by adoptively transferred, interleukin‐2‐activated NK cells leads to destruction of well‐established lung metastases
Authors: Yang Qin , Hokland Marianne E. , Bryant John L. , Zhang Yuquing , Nannmark Ulf , Watkins Simon C. , Goldfarb Ronald H. , Herberman Ronald B. , Basse Per H. 
Published: April 2003

AbstractWe have shown previously that i.v. injection of interleukin‐2‐(IL‐2) activated natural killer (A‐NK) cells together with IL‐2 leads to a substantial localization of the A‐NK cells into most, but not all, well‐established B16 lung metastases in C57BL/6 mice within 12–24 hr. We demonstrate that the morphology of the lung metastases, (loose or more compact in appearance), and their location in the lungs (on the surface or deep in the lung parenchyma) are closely tied to the infiltration‐permissiveness of the metastases as well as their sensitivity to treatment with A‐NK cells. Although more than 1,100 A‐NK cells/mm2 were found in deep metastases with a “loose” morphology (D‐L), only 534, 90 and 89 cells/mm2 were found in surface‐loose (S‐L), surface‐compact (S‐C) and deep‐compact (D‐C) metastases, respectively. The best infiltrated metastases responded best to the A‐NK cell therapy. Thus, metastases of the D‐L phenotype became reduced by 65–90% after treatment with 2 × 106 A‐NK cells and IL‐2 (120,000 IU Peg‐IL‐2 every 12 hr for 3 days) compared to similar lesions in animals treated with PEG‐IL‐2 alone. In contrast, poorly infiltrated metastases, that is lesions of the compact phenotype (D‐C and S‐C) as well as loose metastases on the lung surface (S‐L), did not react significantly to this treatment. We conclude that adoptively transferred A‐NK cells are able to eliminate even well‐established metastases. The existence of metastases that are resistant to infiltration by the transferred effector cells at time of treatment might reduce the efficacy of cell‐based immuno‐therapeutic ventures. © 2003 Wiley‐Liss, Inc.
Decomposition of the complete graph plus a 1‐factor into cycles of equal length
Authors: Šajna Mateja 
Published: April 2003

AbstractWe determine the necessary and sufficient conditions for the existence of a decomposition of the complete graph of even order with a 1‐factor added into cycles of equal length. © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 170–207, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10019
Homogeneous and ultrahomogeneous Steiner systems
Authors: Devillers Alice 
Published: April 2003

AbstractA Steiner system (or t — (v, k, 1) design) S is said to be homogeneous if, whenever the substructures induced on two finite subsets S1 and S2 of S are isomorphic, there is at least one automorphism of S mapping S1 onto S2, and is said to be ultrahomogeneous if each isomorphism between the substructures induced on two finite subsets of S can be extended to an automorphism of S. We give a complete classification of all homogeneous and ultrahomogeneous Steiner systems. © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 153–161, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10034
Largest minimal blocking sets in PG(2,8)
Authors: Barát J. , Innamorati S. 
Published: April 2003

AbstractBruen and Thas proved that the size of a large minimal blocking set is bounded by$q \cdot {\sqrt{q}} + 1$. Hence, ifq = 8, then the maximal possible size is 23. Since 8 is not a square, it was conjectured that a minimal blocking 23‐set does not exist in PG(2,8). We show that this is not the case, and construct such a set. We prove that this is combinatorially unique. We also complete the spectrum problem of minimal blocking sets for PG(2,8) by showing a minimal blocking 22‐set. © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 162–169, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10035
Metal chelate polymers derived from tetraacetylethane
Authors: Charles Robert G. 
Published: April 2003

AbstractPolymeric materials have been prepared by the reaction of the divalent Cu, Ni, Co, Zn, Cd, and Mg cations with the dipotassium salt of tetraacetylethane in methanol–water solutions. The polymers appear to be of low molecular weight and generally contain potassium in the endgroups. The insoluble, infusible, materials decompose on heating in the absence of air to give, among other products, H2, 3,4‐diacetyl‐2,5‐dimethylfuran, and the free metal or metal oxide. The order of decreasing heat stability is Mg > Ni > Co > tetraacetylethane > Cu > Zn > Cd. The Cd chelate polymer decomposes appreciably at 225°C., while the Mg polymer, heated under the same conditions, begins to decompose at about 350°C.
Some aspects of the production and study of semiconducting polymeric materials
Authors: Topchiev A. V. 
Published: April 2003

AbstractThe paper deals with theoretical and experimental data on polymeric products with semiconducting properties. The data show the possibility of producing, on the basis of polymers, particularly polyacrylonitrile, substances characterized by high electroconductivity and exponential dependence of the latter on temperature. Possible changes in electrophysical properties of the materials are discussed. A quasimetallic model of a polymeric semiconductor is described.
Polymerization of allene by organometallic initiation
Authors: Baker William P. 
Published: April 2003

AbstractAllene has been polymerized to a high molecular weight by several transition metal salts reduced by aluminum triisobutyl. The polymer contained three types of unsaturation: vinylidene, vinyl, and cis; no trans unsaturation was found. A hypothesized mechanism accounted for these facts by two competitive rates: reaction of a linear intermediate with monomer to form again the linear intermediate plus one vinylidene unit, and isomerization of the linear intermediate to a cyclic intermediate which ultimately yielded one vinylidene and one vinyl or cis unit after reaction with monomer. Thus, the ratio of the two rates was controlled by the concentration of allene. The suggested mechanism proved to predict accurately the effect of the conditions of polymerization upon the structures of the resulting polymers. The nature of the transition metal also proved of importance in determining the path of polymerization as did temperature, solvent, degree of agitation, and copolymerization. Polyallene was found to exist in three crystalline forms as well as an amorphous form.
Dynamic properties of homo‐ and copolymers of 4‐methyl‐1‐pentene
Authors: Hewett W. A. , Weir F. E. 
Published: April 2003

AbstractDynamic measurements of homo‐ and copolymers of 4‐methyl‐1‐pentene have been made with a self‐damped torsion pendulum. It has been shown that one can calculate the glass transition temperature of these copolymers by means of an equation suggested by T. Fox. It has also been shown that there is a danger in correlating per cent insolubles with crystallinity in a new polymer system without considering molecular weight.
Polymerization induced by ionizing radiation at low temperatures. III. The effect of electron density on the polymerization of substituted styrenes
Authors: Hsia Chen Catherine S. 
Published: April 2003

AbstractThe solution polymerization in methylene chloride of different methyl‐, methoxy‐and chloro‐substituted styrenes has been studied both at a low temperature (−65°C.) and at a higher temperature (+25°C.). The rates of the m‐ and p‐substituted monomers are correlated with the Hammett linear free‐energy relationship at both temperatures and the σ+ constants of Brown and Okamoto. The hypothesis that at low temperatures the polymerization mechanism is cationic and at higher temperatures the mechanism is free‐radical is further supported by a negative value for p at −65°C. and nearly zero value for p at 25°C. obtained from the Hammett plots at the respective temperatures. Solid‐state polymerizations of undiluted p‐methylstyrene, o‐methylstyrene, and α‐methylstyrene also have been investigated. It has been found that the termination is unimolecular for o‐methylstyrene and p‐methylstyrene. The rates for α‐methylstyrene at −80°C. in the solid state are extremely slow. By comparing the results obtained for the solid‐state and for the solution polymerizations of p‐methylstyrene, o‐methylstyrene, and α‐methylstyrene, the hypothesis that the crystal structure plays an important role in determining the rate of solid‐phase polymerization and its mechanism is further substantiated by the differences observed. The polymerization of undiluted p‐methylstyrene at 0°C. and at −15°C. in the liquid phase has been undertaken. It has been found that at both temperatures the polymerization is ionic in nature, as evidenced by the dose rate dependences and by the negative activation energy. The polymerization of p‐methoxystyrene in methylene chloride (∼3.5 moles/1.) has been undertaken from −80°C. to 25°C., covering both solid and liquid phases. In the liquid phase a change of mechanism with change of temperature is again observed. In the solid phase the polymerization is probably of a different nature and is not well understood.
Copolymerization of styrene and styrene derivative with an aluminum alkyl‐titanium trichloride catalyst
Authors: Overberger C. G. , Nozakura S. 
Published: April 2003

AbstractCopolymerizations of styrene with p‐tert‐butyl‐, o‐methyl‐, 2,6‐dimethyl‐, and p‐fluorostyrene were carried out with an alkyl aluminum—titanium trichloride catalyst. Overall composition of the product indicated that substituted styrenes were less reactive than expected for a conventional free‐radical or ionic mechanism in solution. This fact led to a suggestion of a special steric interaction of the penultimate monomeric unit in the propagation step for this heterogeneous system. A styrene–p‐tert‐butylstyrene copolymer was fractionated, showing that it was composed of two or more copolymers of different compositions. The similar situation holds for the other cases except for 2,6‐dimethylstyrene, which did not homopolymerize and did not copolymerize. The result was explained by the assumption of either multiactivity of the catalyst due to differences in site activity or a diffusion‐controlled process.
Thermodynamic properties of solutions of cellulose triacetate
Authors: Moore W. R. , Shuttleworth R. 
Published: April 2003

AbstractThe lowering of vapor pressures of solutions containing 10–50% by weight of cellulose triacetate in chloroform and methylene chloride have been measured at several temperatures. Attempts made to obtain similar data for solutions in s‐tetrachlorethane failed apparently because of decomposition of solvent. Solvent activities, free energies, heats and entropies of dilution are obtained. Both systems become increasingly exothermal as the polymer concentration is increased. In the triacetate‐chloroform system, TΔS̄1 decreases from relatively large values at low concentrations as the concentration is increased resembling comparable secondary cellulose acetate systems with acetone and dioxan as solvents. In the methylene chloride system, TΔS̄1 increases with concentration as in comparable cellulose nitrate‐solvent systems. These results are interpreted in terms of solvation and chain stiffness. Values of the polymer‐solvent interaction parameter x1 increase with concentration and values of the entropy contribution to x1 are greater than those suggested by lattice theories. Expression of volume fraction of polymer in terms of solvated rather than dry polymer should lead to values of x1 and the entropy contribution which are more in keeping with the predictions of lattice theories.
Maximum relaxation time on polymers in the vicinity of critical molecular weight
Authors: Sobue Hiroshi , Murakami Kenkichi 
Published: April 2003

AbstractIt is a well‐known fact that the relaxation spectra in the rubbery region of linear amorphous polymers show “box‐type” functions which are characterized by three elements, τe τm and E0, the minimum relaxation time, maximum relaxation time, and height of the curve, respectively. The equation (τm − τe)/log (τm/τe) = 2.303 αM/Er(τe) can be derived by a simple treatment described in this paper. Then log τe = −log E0/α(1 −1/10K) + β log M̄w can be obtained from the above equation for the polymers synthesized by us. According to Fujita's results, however, τm is independent of molecular weight and τm becomes τ3 when M̄w conforms to Mc. For such a case the above equation is transformed into log (τm/τe − 1) − log log τm/τm = β log M̄w/Mc. On the other hand, log τm experimentally obtained was plotted against log M̄w for the same polymers and it was found that the results were raher on the straight line indicated by the former equation than on the curve shown by the latter. Also log (τm + 0.234) = —5.87 + 1.65 log M̄w was found to be suitable for the polymers in the vicinity of Mc.
Synthesis of styrene–methyl methacrylate nonrandom copolymers in emulsion systems with cobalt‐60 gamma radiation
Authors: Acres G. J. K. , Dalton F. L. 
Published: April 2003

AbstractGraft copolymers have been prepared by the irradiation of polymer latices swollen with monomer. The latices used were prepared by radiation polymerization of emulsions to avoid the presence of initiator molecules in the second stage. Latices of polystyrene swollen with methyl methacrylate and polymethyl methacrylate swollen with styrene have been used. Polymerizations were followed dilatometrically and the dependence of polymerization rate on monomer concentration and radiation intensity obtained for both systems studied. Separation of copolymer from homopolymers has been attempted by thermal gradient elution chromatography; the method proved satisfactory when the solvent—nonsolvent system benzene—petroleum ether was used, but failed to give separations when benzene—methanol was used. This failure is thought to be due to cosolution phenomena.
The chemical and physicochemical properties of wheat starch mildly oxidized with alkaline sodium hypochlorite
Authors: Schmorak J. , Lewin M. 
Published: April 2003

AbstractAn attempt has been made to elucidate the nature of the reaction between alkaline hypochlorite and granular wheat starch. With this end in view various analytical determinations were carried out on starch samples oxidized under well‐determined conditions. The reaction was found to be nonspecific, its main results being the formation of functional groups and the scission of glucosidic bounds. The functional groups formed were mainly carboxyls, some carbonyl formation taking place at lower pH values. The consumption of about 0.05 atom of oxygen/AGU resulted in an extensive degradation of both starch components. There are indications to the effect that degradation is random in type. On that assumption, 0.5 to 1 glucosidic bonds in 100 were scinded, each scission being accompanied by the formation of about two carboxyl groups and by an overall consumption of 4–5 oxygen atoms. The reaction apparently took place in the amorphous part of the granule. The amylose‐amylopectin ratio, as well as the granule size remained unchanged. More than one‐quarter of the total oxygen consumed reacted with the dissolved portion of the starch as the result of the oxidation.
Polymerization of alicyclic epoxides with aluminum alkyl catalysts
Authors: Bacskai R. 
Published: April 2003

AbstractThe polymerization of alicyclic epoxides with aluminum alkyls has been investigated. In many cases, fast polymerization rates were observed at −78°C., leading to high molecular weight compounds in good yield. The infrared spectra of the polymers are consistent with the proposed polyether structure. It was found that the molecular weight of the polymers obtained in these reactions is a function of the alicyclic ring size. This was interpreted by considering the variation of molecular strain during the polymer‐forming reaction. The following order of reactivity based on estimated propagation rates has been established for the monomers: cyclohexene oxide > cyclopentene oxide > cycloheptene oxide » cyclooctene oxide. A reaction mechanism is proposed where initiation occurs through coordination of the aluminum alkyl with the epoxide, followed by successive addition of monomers to the electrophilic centers. The absence of phenyl endgroups in a relatively low molecular weight polycyclohexene oxide, prepared with Al(C6H5)3 catalyst, precludes one of the possible alternative mechanisms. The proton magnetic resonance spectra of polycyclohexene oxide, cis‐1,2‐cyclohexanediol, and trans‐1,2‐cyclohexanediol were determined in dilute chloroform solution and suggest a stereoregular poly‐trans‐ether structure for the polymers.