bluuebunny/crossref_metadata_2025 huggingface dataset:
15‐Membered Triolefinic Macrocycles − Catalytic Role of (E,E,E)‐1,6,11‐Tris(arenesulfonyl)‐1,6,11‐triazacyclopentadeca‐3,8,13‐triene Complexes of Palladium(0) in the Presence of Phosphanes
Authors: Moreno‐Mañas Marcial , Pleixats Roser , Spengler Jan , Chevrin Carole , Estrine Boris , Bouquillon Sandrine , Hénin Françoise , Muzart Jacques , Pla‐Quintana Anna , Roglans Anna
Published: December 2002

The palladium(0) complexes of (E,E,E)‐1,6,11‐tris(arenesulfonyl)‐1,6,11‐triazacyclopentadeca‐3,8,13‐trienes deliver palladium to phosphanes with the generation of high concentrations of catalytically active species such as Pd(PPh3)2. After oxidation of the phosphanes, the palladium is reincorporated into the macrocycle, thus avoiding agglomeration and precipitation. These conclusions were reached by 31P NMR, 19F NMR, and electrospray ionization mass spectrometry studies of telomerization and Tsuji−Trost reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Plakohypaphorines A−C, Iodine‐Containing Alkaloids from the Caribbean Sponge Plakortis simplex
Authors: Campagnuolo Claudio , Fattorusso Ernesto , Taglialatela‐Scafati Orazio
Published: December 2002

Investigation of the most polar fractions obtained from the organic extract of the Caribbean marine sponge Plakortis simplex has led to the isolation of three novel iodine‐containing tryptophan betaines structurally related to the known hypaphorine (5), which have been named plakohypaphorine A (2), B (3) and C (4). Their structures have been determined by spectroscopic methods. Isolation of compounds 2−4 is particularly remarkable since it represents the first finding of iodoindole derivatives in a natural source, either marine or terrestrial. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
An Efficient Synthesis of 1‐Naphthylbis(oxazoline) and Exploration of the Scope in Asymmetric Catalysis
Authors: van Lingen Hester L. , van de Mortel Jeroen K. W. , Hekking Koen F. W. , van Delft Floris L. , Sonke Theo , Rutjes Floris P. J. T.
Published: December 2002

Both enantiomers of 1‐naphthylglycine were obtained in 99%eeby enzymatic resolution of the corresponding racemic amino acid amide, giving access to the novel ligands (R)‐ and (S)‐naphthylbis(oxazoline). Initial studies provided insight into the scope and limitations of the (S)‐naphthyl‐substituted bis(oxazoline) and its steric influence compared to other bis(oxazolines) in catalytic asymmetric synthesis. (© Wiley‐VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2003)
Cycloisomerisations in Pd‐Catalysed Spiroannulations onto Chiral Pyrazine Derivatives
Authors: Møller Bjørg , Undheim Kjell
Published: December 2002

A method for 5‐exo‐trig‐spiroannulations is described which uses the Pd complex trans‐bis(μ‐acetato)bis[o‐(di‐o‐tolylphosphanyl)benzyl]dipalladium(II) as catalyst in cyclisation reactions of dienes with the chiral auxiliary (2R)‐2,5‐dihydro‐2‐isopropyl‐3,6‐dimethoxypyrazine. Extensive NMR assignments are described and used in structure determinations. Isomer identification has been verified by a separate unequivocal synthesis. Nickel catalysis with MeMgBr was compatible with cross‐coupling in the spiroannulated chiral auxiliary. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Diastereoreactivity of a Chiral Oxathiane Derived from 5‐Hydroxy‐1‐tetralone
Authors: Solladié‐Cavallo Arlette , Balaz Milan , Salisova Marta
Published: December 2002

The diastereoreactivity at the CH2 bridge of a cis‐oxathiane derived from 5‐hydroxy‐1‐tetralone (unprotected and protected at the OH) was studied, and it appeared that all reactions at C‐2 provided equatorial substitution. It was also found that: i) reductions of the equatorial benzoyl derivative with selectrides provided high diastereoselectivities at C‐2′ while LAH did not. Methyl Grignard addition was less selective and the selectivity of the propanoyl analogue was smaller; ii) condensation of aldehydes and/or ketones with the lithio derivative provided high equatorial diastereoselectivities at C‐2 but low or nil diastereoselectivities at C‐2′; iii) lithiation at C‐2 was possible only with the oxathiane unsubstituted at C‐2 (CH2) and not possible with derivatives substituted at C‐2 (CHR), perhaps due to the conformational rigidity of this oxathiane in the lithiation transition state and to the equatorial demand of all substituents at C‐2, including lithium. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Asymmetric Synthesis of 1,3‐Dithiolane Nucleoside Analogues
Authors: Caputo Romualdo , Guaragna Annalisa , Palumbo Giovanni , Pedatella Silvana
Published: December 2002

We report the ready asymmetric synthesis of nucleoside analogues containing a 1,3‐dithiolane ring that mimics the sugar moiety of natural nucleosides. The synthesis is accomplished in three main steps from benzoyloxyethanal 1,3‐dithiolane, the key step being its conversion into a chiral monosulfoxide by a modified Sharpless sulfo‐oxygenation reaction. The nucleoside analogues were obtained in good overall yields and with excellent enantiomeric excesses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
TEMPO‐Mediated Anodic Oxidation of Methyl Glycosides and 1‐Methyl and 1‐Azido Disaccharides
Authors: Schämann Matthias , Schäfer Hans J.
Published: December 2002

Methyl glycosides of L‐sorbopyranoside, D‐fructopyranoside, D‐glucosaminopyranoside, 2,3‐dehydro‐2,3‐dideoxyglucopyranoside, cellobiose, lactose, and maltose and the 1‐azido derivatives of glucose, cellobiose, lactose, and maltose have been converted into the corresponding uronic acids in moderate to excellent yields by TEMPO‐mediated anodic oxidation. The anode proves to be an advantageous alternative to other cooxidants in TEMPO+ oxidations of carbohydrates and is compatible with N‐acylamino and azido groups and with double bonds. The electrolyte, a carbonate buffer, can easily be removed with a cation‐exchange resin, a facile scale‐up by increasing the electrode area is possible. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Functionalization of 9‐(Dicyanomethylene)fluorene Derivatives with Substituted Acetylenes
Authors: Wong Wai‐Yeung , Lu Guo‐Liang , Choi Ka‐Ho , Lin Zhenyang
Published: December 2002

Treatment of (2,7‐dibromo‐9H‐fluoren‐9‐ylidene)malononitrile (1) with excesses of substituted acetylenes RC≡CH [R = Ph, MeC6H4, (η5‐C5H5)Fe(η5‐C5H4)] under Sonogashira coupling catalytic conditions afforded novel 9‐[cyano(ethynyl)methylene]fluorene derivatives 2−4, respectively, in moderate yields. In these reactions, facile functionalization occurs at the 9‐methylene position in the fluorene, one of the cyano groups being substituted by an acetylide moiety. In order to prepare the 2,7‐diethynyl‐substituted 9‐(dicyanomethylene)fluorene compounds 8−10, palladium‐catalyzed coupling reactions between 2,7‐dibromofluoren‐9‐one and RC≡CH in a 1:2 molar ratio first have to be carried out, initially resulting in the formation of compounds 5−7 in good yields. Upon subsequent thermal treatment of 5−7 with malononitrile in DMSO, compounds 8−10 can be isolated in high purity. All attempts to obtain 8−10 from direct coupling of 1 and RC≡CH failed. Single‐crystal X‐ray structural analyses and density functional calculations have been performed on 3, 4, 7, and 8. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of “V‐Shaped” syn‐Bidentate Ligands Based on Mesitylene‐Derived [1.1.1.1]Metacyclophane Blocked in a 1,3‐Alternate Conformation
Authors: Klein Cédric , Graf Ernest , Hosseini Mir W. , De Cian André , Kyritsakas‐Gruber Nathalie
Published: December 2002

A series of five new syn‐bidentate ligands 14−18 based on the [1.1.1.1]metacyclophane backbone blocked in a 1,3‐alternate conformation was achieved. The common building block for the preparation of ligands bearing two interaction sites located in a syn fashion (CN, SMe, p‐pyridyl, p‐methoxyphenyl and p‐methylthiophenyl) is the dibromo derivative 12. All reported ligands were fully characterised by classical analytical methods and their 1,3‐alternate conformation demonstrated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Oviductal sperm storage structure and their changes during the seasonal (dissociated) reproductive cycle in the soft‐shelled turtle Lissemys punctata punctata
Authors: Sarkar Supriti , Sarkar N.K. , Maiti B.R.
Published: December 2002

The oviduct of the Indian fresh water soft‐shelled turtle Lissemys punctata punctata was examined throughout the year under light and scanning electron microscopes to determine the location, histomorphological characteristics, and function of sperm storage structure, as well as their changes at different phases of the seasonal reproductive cycle. Sperm storage structures in the form of tubules were observed in the wall of isthmus throughout the year. These tubules developed either by folding or fusion of the oviductal mucosal folds and were lined by both ciliated and nonciliated epithelial cells. The height and secretory activities of the epithelia were markedly high during the breeding phase (August to September) but low in the nonbreeding phase (October to June). A few short tubules lined by cuboidal epithelium appear in the wall of infundibulum only during the breeding phase. Following mating (May), inseminated sperm were stored within the tubules of isthmus up to the pre‐ovulatory stage (August). Thereafter, sperm associated with PAS‐positive materials secreted from the epithelium (referred to as a carrier matrix) moved forward to the infundibulum and were stored within the storage tubules of the infundibulum for a short time. Subsequently, sperm evacuated the storage tubules and entered the oviductal lumen to fertilize the subsequently ovulated eggs during or prior to ovulation. The isthmus‐tubules become shorter and narrower in the regressive phase (October to November) and remained so until the early preparatory phase (April). Sperm release might have been stimulated by estrogen secreted from the ovarian follicles of pre‐ovulatory turtles. Stored sperm not utilized for fertilization remained viable not less than six months in the present turtle species. J. Exp. Zool. 295A:83–91, 2003. © 2003 Wiley‐Liss, Inc.
Balancing tissue perfusion demands: cardiovascular dynamics of cancer magister during exposure to low salinity and hypoxia
Authors: McGaw Iain J. , McMahon Brian R.
Published: December 2002

Decapod crustaceans inhabit aquatic environments that are frequently subjected to changes in salinity and oxygen content. The physiological responses of decapod crustaceans to either salinity or hypoxia are well documented; however, there are many fewer reports on the physiological responses during exposure to these parameters in combination. We investigated the effects of simultaneous and sequential combinations of low salinity and hypoxia on the cardiovascular physiology of the Dungeness crab, Cancer magister. Heart rate, as well as haemolymph flow rates through the anterolateral, hepatic, sternal and posterior arteries were measured using a pulsed‐Doppler flowmeter. Summation of flows allowed calculation of cardiac output and division of this by heart rate yielded stroke volume. When hypoxia and low salinity were encountered simultaneously, the observed changes in cardiac properties tended to be a mix of both factors. Hypoxia caused a bradycardia, whereas exposure to low salinity was associated with a tachycardia. However, the hypoxic conditions had the dominant effect on heart rate. Although hypoxia caused an increase in stroke volume of the heart, the low salinity had a more pronounced effect, causing an overall decrease in stroke volume. The patterns of haemolymph flow through the arterial system also varied when hypoxia and low salinity were offered together. The resulting responses were a mix of those resulting from exposure to either parameter alone. When low salinity and hypoxia were offered sequentially, the parameter experienced first tended to have the dominant effect on cardiac function and haemolymph flows. Low salinity exposure was associated with an increase in heart rate, a decrease in stroke volume and cardiac output, and a concomitant decrease in haemolymph flow rates. Subsequent exposure to hypoxic conditions caused a slight decrease in rate, but other cardiovascular variables were largely unaffected. In contrast, when low salinity followed acclimation to hypoxic conditions, apart from an increased heart rate, there were no other cardiovascular changes associated with the low salinity episode. The implications of these changes in cardiovascular dynamics are discussed in relation to physiological mechanisms and the ecology of decapod crustaceans, in hypoxic or low salinity environments. J. Exp. Zool. 295A:57–70, 2003. © 2003, Wiley‐Liss, Inc.
Lactic acid is absorbed from the small intestine of sheep
Authors: Ding Zhaokun , Xu Youqing
Published: December 2002

A series of experiments was conducted in vivo on anaesthetized sheep to explore the hypothesis that lactic acid is absorbed from the small intestine of sheep. Test solutions varying in lactic acid concentration, pH, osmolarity, and with fixed physiological concentrations of volatile fatty acids (VFAs), K+, Na+, NH4+, Cl−, and PO4−3, were separately introduced into clean, surgically sealed pouches. Studies were undertaken in 27 sheep, each with three pouches in the middle of the duodenum, jejunum, and ileum. Samples were taken at 15‐minute intervals for 60 minutes to determine the absorption rates. The experimental results showed that L‐ and D‐lactic acid were absorbed from the pouches of the duodenum, jejunum, and ileum throughout the 60 minutes. In the test solutions with pH 5.3, 420mOsmol/kg, and 12.5mM lactic acid that are in vivo conditions of light lactic acidosis, the mean absorption rates of D‐lactic acid and L‐lactic acid pooled from three pouches were similar, 0.07μmol/cm2/min and 0.06μmol/cm2/min, respectively, based on absorptive surface area. The mean absorption rates of DL‐lactic acid from the duodenum, jejunum, and ileum pouches were almost the same, 0.14, 0.14, and 0.11μmol/cm2/min, respectively. The absorption of lactic acid varied depending on lactic acid concentration, and there was a curvilinear relationship between lactic acid concentration and its absorption rate. A decrease in pH and osmotic pressure resulted in significant, corresponding increases in the absorption of lactic acid (P<0.0001 and P<0.05, respectively). J. Exp. Zool. 295A:29–36, 2003. © 2003 Wiley‐Liss, Inc.
Paracrine interactions of mammalian adipose tissue
Authors: Pond Caroline M.
Published: December 2002

Adipose tissue develops in and/or around most lymphoid tissues in mammals and birds. Early reports of this widespread association and hypotheses for its functional basis were long ignored in the planning of in vitro studies and the interpretation of in vivo results. Biochemical studies on rodent tissues reveal many site‐specific properties of adipocytes anatomically associated with lymph nodes and omental milky spots that equip them to interact locally with lymphoid cells. The paracrine interactions are strongest for the most readily activated lymph nodes and are modulated by dietary lipids. Perinodal adipocytes contribute less than those in the large nodeless depots to whole‐body lipid supplies during fasting. Observations on wild animals show that perinodal adipose tissue is selectively conserved even in starvation but does not enlarge greatly in natural obesity. Such paracrine provisioning of peripheral immune responses improves their efficiency and emancipates activated lymphocytes from competition with other tissues for blood‐borne nutrients. The relationship is found in extant protherians and metatherians, so it almost certainly arose early in the evolution of mammals, possibly as part of the metabolic reorganisation associated with homeothermy, viviparity, and lactation. Prolonged disruption to paracrine interactions between lymphoid and adipose tissue may contribute to the HIV‐associated adipose redistribution syndrome, causing selective hypertrophy of the mesentery, omentum, and other adipose depots that contain much activated lymphoid tissue. Skeletal and cardiac muscle may also have paracrine relationships with anatomically associated adipose tissue, but interactions between contiguous tissues have not been demonstrated directly. J. Exp. Zool. 295A:99–110, 2003. © 2003 Wiley‐Liss, Inc.
Theoretical Model for the One‐Dimensional Temperature and Stress Calculation of Simple Hot Plate Welded Geometries
Authors: Potente Helmut , Schnieders Joachim , Bornemann Markus
Published: December 2002

In the field of hot plate welding, experimental investigations show that the stress cracks are caused by inherent stresses in the component, which are induced in the part while it is being heated on the tool. For the better understanding of the process parameters and their effects on the phenomenon of stress cracking, a simple theoretical model for the calculation of the temperature and the stress field is to be developed. The application of the presented method shows the effects of the process parameters on the phenomenon of stress cracking and correlates with the experimental results of further investigations.

Theoretical stress distribution.

magnified image

Theoretical stress distribution.
Serine protease inhibitor‐E2 (SERPINE2) is differentially expressed in granulosa cells of dominant follicle in cattle
Authors: Bédard Julie , Brûlé Sophie , Price Christopher A. , Silversides David W. , Lussier Jacques G.
Published: December 2002

The objective was to analyze gene expression in bovine granulosa cells of the dominant follicle by mRNA differential display. Total RNA was extracted from granulosa cells of ≤4 mm follicles, day 5 (D5) dominant follicles, and hCG‐induced preovulatory follicles. A differentially expressed cDNA observed in the dominant follicle group was used to screen a granulosa cell cDNA library, which resulted in the cloning of a 2,096 bp cDNA. Amino acid comparison showed identity level of 91.4, 83.9, and 83.1% when compared to human, rat, and mouse serine protease inhibitor E2, SERPINE2, also called Glia‐derived nexin or protease Nexin‐1. A single transcript of 2.4 kb was shown to be differentially expressed in different bovine tissues. Immunoblotting with a specific antibody raised against a fragment of SERPINE2 (S12‐R196) showed that SERPINE2 migrated at 47.5 kDa in support of glycosylation. Primordial, primary, and secondary pre‐antral follicles showed immunostaining associated with granulosa cells and oocytes, and strong labeling in large antral follicles was located with granulosa cells and follicular fluid. Heterogeneity of SERPINE2 labeling was observed in CL. Semi‐quantitative real‐time fluorescent RT‐PCR showed a six‐fold increase (P = 0.0002) in mRNA level of SERPINE2 in granulosa cells of D5 dominant follicle compared to granulosa cells collected from the ≤4 mm or preovulatory hCG‐induced follicles. This report demonstrates that SERPINE2 mRNA is regulated in a spatio–temporal pattern with highest levels in granulosa cells of growing dominant bovine follicles, and support the hypothesis that a high expression of SERPINE2 may contribute to follicular growth whereas a decrease following hCG injection may contribute to ovulation. Mol. Reprod. Dev. 64: 152–165, 2003. © 2003 Wiley‐Liss, Inc.
Capacity of adult and prepubertal mouse oocytes to undergo embryo development in the presence of cysteamine
Authors: de Matos D.G. , Nogueira D. , Cortvrindt R. , Herrera C. , Adriaenssens T. , Pasqualini R.S. , Smitz J.
Published: December 2002

The present study was carried out to study de novo glutathione (GSH) synthesis and to evaluate the effect of stimulating GSH synthesis during in vitro maturation (IVM) of adult and prepubertal mouse oocytes on the embryo developmental rate. Adult (8 weeks old) and prepubertal mice (24–26 days old) were primed with 5 IU of PMSG and oocytes were retrieved from the ovary 48 hr later for IVM. After IVM (18 hr) Cumulus oocyte complexes (COC) were in vitro fertilized (IVF) and in vitro culture (IVC) in order to observe embryo development. The IVM medium was supplemented with: 0, 25, 50, 100, or 200 μM of cysteamine. To study the novo GSH synthesis, 5 mM BSO was added during IVM of adult or prepubertal oocyte. Developmental rates up to blastocyst were recorded for each group. Experiments also included a group of ovulated oocytes (in vivo matured) after priming with PMSG and HCG. After IVM of adult mice oocytes, an improvement was observed on embryo development in all the supplemented groups when compared with the untreated group (P < 0.05). No differences were observed in blastocyst rate among IVM oocytes with cysteamine and ovulated oocytes. Prepubertal IVM mouse oocytes had a lower cleavage rate compared with ovulated oocytes (P < 0.05). Cysteamine failed to improve prepubertal oocytes developmental rates (P > 0,05). 2‐cell embryos, coming from IVM prepubertal oocytes and ovulated oocytes had the same preimplantation developmental rate up to the blastocyst stage. In prepubertal, and adult oocytes an inhibition of embryo development was observed when buthionine sulfoximide (BSO), a specific inhibitor of the γ‐glutamylcysteine synthetase, was added during oocyte maturation (P < 0.01). In conclusion, an improvement in mouse embryo development was observed when cysteamine was added to the IVM medium of adult mice oocytes. In prepubertal oocytes cysteamine addition during oocyte maturation failed to improve embryo developmental rates. The presence of BSO lowered or completely blocked blastocyst development. This proves that, de novo GSH synthesis during oocyte maturation of adult and prepubertal oocytes undoubtedly plays an important role in embryo development. The improvement on oocyte competence observed in adult mice oocytes is probably related to intracellular GSH synthesis stimulated by cysteamine. Nevertheless the reason why cysteamine failed to improve prepubertal oocytes competence remains as an open question. Mol. Reprod. Dev. 64: 214–218, 2003. © 2003 Wiley‐Liss, Inc.
Co‐expression and interaction of cubilin and megalin in the adult male rat reproductive system
Authors: Van Praet Oliver , Argraves W. Scott , Morales Carlos R.
Published: December 2002

Cubilin is a peripheral membrane protein that cooperates with the endocytic receptor megalin to mediate endocytosis of ligands in various polarized epithelia. Megalin is expressed in the male reproductive tract where it has been implicated in the process of sperm membrane remodeling. A potential role for cubilin in the male reproductive tract has not been explored. Using RT‐PCR, we found that cubilin and megalin mRNAs are expressed in the efferent ducts, corpus and cauda epididymis, and proximal and distal vas deferens. Immunohistological analysis revealed that cubilin was expressed in nonciliated cells of the efferent ducts, principal cells of the corpus and cauda epididymis and vas deferens. Immunogold EM showed cubilin in endocytic pits, endocytic vesicles, and endosomes of these cells. The expression profile of cubilin in the male reproductive tract was coincident with that of megalin except in principal cells of the caput epididymis. Double immunogold labeling showed that cubilin and megalin co‐localized within the endocytic apparatus and recycling vesicles of efferent duct cells. Neither protein was found in lysosomes. Injection of RAP, an antagonist of megalin interaction with cubilin, reduced the level of intracellular cubilin in cells of the efferent ducts and vas deferens. In conclusion, cubilin and megalin are co‐expressed in cells of the epididymis and vas deferens and the endocytosis of cubilin in these tissues is dependent on megalin. Together, these findings highlight the potential for a joint endocytic role for cubilin and megalin in the male reproductive tract. Mol. Reprod. Dev. 64: 129–135, 2003. © 2003 Wiley‐Liss, Inc.
Expression and location of taurine transporters and channels in the epididymis of infertile c‐rosreceptor tyrosine kinase‐deficient and fertile heterozygous mice
Authors: Xu Y.‐X. , Wagenfeld A. , Yeung C.‐H. , Lehnert W. , Cooper T.G.
Published: December 2002

Defective sperm volume regulation causes infertility in c‐rosknockout (KO) mice lacking the initial segment of the epididymis (IS). As taurine is in high concentration in the male tract and acts as an organic osmolyte in somatic cells, the taurine transporter (TauT), taurine content and taurine channel phospholemman (PLM) were examined in the epididymides of these and fertile heterozygous (+/−) mice. TauT and PLM genes were demonstrated by RT‐PCR in the caput of +/− and c‐rosknockout males. Northern blots revealed one transcript ofTauT(8 kb) in all regions with different expression between segments (cauda > corpus > IS > caput) and no differences in expression between genotypes. Western blotting revealed three translation products of TauT in all epididymal regions (107, 69, 49 kDa) with higher expression of the 69 kDa and 49 isoforms in the −/− than +/− caput. Immunohistochemical staining revealed staining of principal cells and stronger staining of apical and clear cells in all epididymal regions. The expression of the PLM transcript (0.75 kb: cauda = corpus > caput > IS) was upregulated in the proximal caput and cauda of KO mice. Tissue taurine was higher in the cauda >corpus>IS ≅ caput in fertile males and significantly higher in the proximal caput of the KO male. By contrast, taurine concentrations in cauda epididymidal fluid and content per 106sperm did not differ between genotypes. TauT and PLM may be involved in taurine regulation in the normal epididymis and the proximal accumulation of taurine in the infertile males. Mol. Reprod. Dev. 64: 144–151, 2003. © 2003 Wiley‐Liss, Inc.
Effects of acute amitriptyline administration on memory, anxiety and activity in male and female mice
Authors: Parra Andrés , Everss Estrella , Monleón Santiago , Vinader‐Caerols Concepción , Arenas M. Carmen
Published: December 2002

The effects of acute administration of amitriptyline on memory consolidation in male and female CD1 mice were investigated. Three doses of this tricyclic antidepressant (7.5, 15 and 30 mg/kg) were administered immediately after inhibitory avoidance training. Forty‐five minutes after injection, subjects explored the elevated plus‐maze for five minutes. Subjects were tested for avoidance twenty‐four hours later. Amitriptyline impaired inhibitory avoidance consolidation at doses 7.5, 15 and 30 mg/kg in males, and at doses 7.5 and 30 mg/kg in females. In the elevated plus‐maze, amitriptyline had no effect on anxiety (percentage of open arm entries) and induced a dose‐dependent impairment of activity (number of closed arm entries). The observed sex differences were limited to subtle stronger effects of amitriptyline in males than in females on inhibitory avoidance. These results indicate that acute amitriptyline administration produces retrograde amnesia on inhibitory avoidance, which does not seem be mediated by anxiolytic effects.
Effects of L‐arginine on the brain ischaemia‐reperfusion damage in rats: An investigation by somatosensory evoked potentials and histopathology
Authors: Kurt Tülay , Oğuzhanoğlu Atilla , Ortaç Ragıp , Turman Bülent , Adıgüzel Esat
Published: December 2002

We investigated whether administration of L‐arginine reduces the ischaemia‐reperfusion damage in the rat brain. The effects of L‐arginine were evaluated by means of somatosensory evoked potential (SEP) measurements and quantitative histopathological investigations. There was no significant difference between groups based on SEP data. The results obtained from quantitative histopathological investigations indicate that the nitric oxide (NO) precursor L‐arginine does not appear to have a protective effect on the brain ischaemia‐reperfusion damage. Furthermore, histopathological evaluation revealed a higher number of damaged cells in the L‐arginine treated rats than in control group. The results of the present study suggest that high concentrations of L‐arginine present in later stages of reperfusion might have harmful effects on reperfusion damage in the brain.
Design and Experimental Characterization of Low‐Volume PM10/2.5/1.0 Trichotomous Sampler Inlet
Authors: Kim Hyun T. , Lee Ken W. , Lee Seung J.
Published: December 2002

This paper presents the development and laboratory evaluation of a PM10/2.5/1.0 trichotomous sampling inlet that consists of two main parts: a previously designed PM10 size‐selective inlet part and a PM2.5/1.0 two‐stage virtual impactor, which was newly fabricated and attached serially to the PM10 size selective inlet part. Particles are collected in three locations through the trichotomous sampling inlet to provide for not only particle concentration measurements of PM10, PM2.5 and PM1.0, but also those of PM2.5–10 and PM1.0–2.5.
Instrumentation for Simultaneous Gas and Particle Velocity Measurements at Mach 5
Authors: Micheli Francis , Losfeld Gilles , Pérotto Myriam , Soulevant Didier
Published: December 2002

This study deals with re‐entry vehicles passing through high‐altitude clouds of ice particles. The particles disturb the flow field and are erosive, thereby increasing the turbulent heat flux considerably. Measurements were performed in a blow‐down wind tunnel to analyze the effects of a particle field on the flow. The wind tunnel flow was seeded by two aerosols. The first was used for LDV flow velocity measurements. Its size was checked by the analysis of its passage through a plane shock wave. The second aerosol was made of uniform micro‐spheres of 200 μm diameter, used to simulated the water droplets. The velocity, feeding and scattering of the latter aerosol need to be accurately measured. The velocities of the flow field and of the micro‐spheres were measured simultaneously by laser velocimetry. This paper describes the instruments used to seed, ascertain and measure this flow with two aerosols.
Determination of the Breakage and Wetting Parameters of Calcite and Their Correlations
Authors: Yekeler Meftuni , Ozkan Alper
Published: December 2002

This paper presents the breakage and wetting parameters of calcite mineral obtained experimentally and establishes a correlation between these characteristic parameters. The breakage parameter obtained from the different feed sizes of grinding is the specific rate of breakage (Si). The wettability parameter, obtained from surface chemistry‐based processes such as contact angle measurements or flotation methods, is the critical surface tension of wetting of a solid or mineral (γc). Calcite mineral, studied for the determination of the above parameters and their correlations, was ground in a laboratory‐size ceramic ball mill with dry, wet and chemically aided grindings and tested extensively to determine the γc values by using a contact angle goniometer and a newly designed micro‐column flotation cell. The highest Si value obtained was 0.35 min−1 for sodium dodecyl sulfate (SDDS)‐aided grinding, and the lowest Si value was 0.26 min−1 for dry grinding of the −600+425 feed in the mill. The γc values for calcite were obtained as 34.0–34.9 mN/m for SDDS‐treated calcite surfaces, 29.9–31.4 mN/m for sodium oleate‐treated surfaces and >72 mN/m for both dry and wet ground products whose surfaces were not treated chemically. Some correlations were established between the Si and γc parameters; as the Si increases, γc decreases, indicating that relatively more hydrophobic surfaces are broken faster for the largest sizes, resulting in higher Si values with more fines (lower γ of Bi, j) in the finer size distribution region (i.e. −150 μm).
Determination of the Refractive Index of Water‐dispersible Granules for Use in Laser Diffraction Experiments
Authors: Saveyn Hans , Mermuys Dries , Thas Olivier , van der Meeren Paul
Published: December 2002

Modern laser light scattering equipment can cover a very broad particle size range by using complex algorithms, such as the Mie theory. A disadvantage of this theory, however, is that it requires the knowledge of the refractive index of the particles, which is not straightforward for powdered organic substances. In this study, thiram, a common dithiocarbamate fungicide, was used as a model compound. In a first part, a method was elaborated to determine the refractive index, based on refractive index measurements of solutions of the compound of interest in a range of solvents. Two different extrapolation techniques were compared. Both techniques were validated by applying them to the determination of the refractive indices of poly(vinyl acetate) and poly(methyl methacrylate). Secondly, the influence of the refractive index value on the generated particle size distribution in the laser diffraction software was investigated. It was observed that widely different particle size distributions can be generated by the laser diffraction software for a single experimental data‐set. Therefore, accurate refractive index information is required to obtain reliable particle size distribution results.
Ab Initio Study on Interactions in Difluoroamine Clusters from one to four Molecules
Authors: Ju Xue‐Hai , Xiao He‐Ming
Published: December 2002

Ab initio calculations at HF, MP2 levels of theory with 6‐311G* basis set in combination with counterpoise procedure for BSSE correction have been performed on difluoroamine clusters consisting of up to four molecules. The dimer, trimer and tetramer were all found to exhibit two minima. There are two types of clusters: cyclic and chain. The corrected bond energies are 9.19, 19.22 and 33.67 kJ/mol at the MP2/6‐311G*//HF/6‐311G* level for the more stable dimer, trimer and tetramer, respectively. The contribution of cooperative effect to the interaction energy is quite significant in the cyclic clusters, but negligible in the chain ones. There exist H‐bonds which involve six and eight F⋅⋅⋅H contacts at ca. 0.23–0.24 nm in cyclic trimer and cyclic tetramer, respectively. The intermolecular interaction is an exothermic process under 400.0 K accompanied by a decrease in the probability of complex formation, and the interactions become weak as temperature increases.
Metal‐Fluorocarbon‐Pyrolants IV: Thermochemical and Combustion Behaviour of Magnesium/Teflon/Viton (MTV)
Authors: Koch Ernst‐Christian
Published: December 2002

The thermochemical and combustion behaviour of pyrotechnic payloads based on magnesium, Teflon® and Viton®, so‐called MTV is discussed. Thermochemical and FTIR‐spectroscopic analysis of magnesium/Teflon® combustion residues indicates the intermediate formation of a Grignard‐type CMgF compound in the condensed phase as part of a preignition reaction (PIR). The PIR is mainly responsible for the observed burning rate which rises exponentially with rising magnesium weight fractions from ξ(Mg)∼0.2 to ξ(Mg)∼0.70 and declines at ξ(Mg)>∼0.70. A tentative mechanism for the combustion process is presented.
A Simple Relation between the Detonation Velocity of an Explosive and its Gurney Energy
Authors: Koch André , Arnold Niklaus , Estermann Markus
Published: December 2002

Based on energetic considerations, we deduce a simple link between the detonation velocity D of an explosive and its Gurney energy EG, namely $\rm{ \sqrt {2E_G } = D/3.08}$. The calculations rely on classical results of detonation theory, linked to the assumption of adiabatic expansion of the gaseous detonation products.
Phase transitions and amorphization of CaWO4 at high pressure
Authors: Errandonea Daniel , Somayazulu Maddury , Häusermann Daniel
Published: December 2002

The structural phase transitions in CaWO4 were studied by in situ energy‐dispersive X‐ray diffraction in a diamond‐anvil‐cell under high pressure up to 65 GPa at room temperature. The previously reported phase transition detected by Raman spectroscopy at 10 GPa was observed in our experiments at 12 GPa and the high‐pressure phase was characterized. This transition is from the tetragonal scheelite structure (I41/a) of CaWO4 to a monoclinic wolframite‐type structure (P2/c) and a small discontinuity in the evolution of the unit‐cell volume was detectable during the transformation (ΔV/V < –1.9%). In addition, we observed that CaWO4 becomes amorphous at pressures exceeding 40 GPa and found that a novel high‐pressure phase of CaWO4 can be obtained at 45 GPa after heating to 477 K and quenching to room temperature an amorphous sample.
Optical identification of impurity levels in strongly phosphorus‐doped wide‐gap II–VI bulk semimagnetic semiconductors
Authors: Van Khoi Le , Kossut J. , Gałazka R.R.
Published: December 2002

Zn1–xMnxTe and Cd1–xMnxTe crystals doped with phosphorus have been investigated by means of the measurement of Hall effect, photoluminescence and reflectance. By annealing under high pressure of nitrogen (up to 4 MPa) at T = 800 °C for a week, a free hole density as high as 5 × 1018 cm–3 was achieved in Zn0.95Mn0.05Te, while in Cd0.99Mn0.01Te it was only 8 × 1016 cm–3. The phosphorus acceptor binding energy in Zn0.975Mn0.025Te and Cd0.99Mn0.01Te was found to be (0.036 ± 0.002) eV and (0.054 ± 0.002) eV, respectively.
Double thermal donors in Czochralski‐grown silicon heat‐treated under atmospheric and high hydrostatic pressures
Authors: Emtsev V. V. , Ammerlaan C. A. J. , Emtsev V. V. , Oganesyan G. A. , Andreev B. A. , Kuritsyn D. I. , Misiuk A. , Surma B. , Londos C. A.
Published: December 2002

The formation kinetics of Thermal Double Donors, a dominant family of thermal donors in Czochralski‐grown silicon annealed at T < 600 °C, is studied in detail. A striking enhancement effect of hydrostatic pressures of about 1 GPa on their formation processes, even in a temperature region of thermal instability of these donor centers at about T = 600 °C under normal conditions, is clearly demonstrated. The experimental data obtained in the present work are in agreement with the recent theoretical calculations of oxygen diffusion and agglomeration processes in heat‐treated Si.
Selective magneto‐luminescence spectroscopy of donoacceptor pairs in n‐GaAs
Authors: Wysmolek A.
Published: December 2002

The results of selective magneto‐luminescence measurements of donoacceptor pairs in n‐type GaAs are discussed. The experimental data are compared with the calculated energy levels of a hydrogen‐like atom in a magnetic field, enabling us to identify a large number of high angular momentum states of the hydrogen‐like impurity in magnetic fields. It is shown that in addition to intra‐donor transitions, the spin‐flip excitations of donor–acceptor pairs involving heavy and light holes can be observed, yielding information about g‐factors for heavy and light holes. For the pairs with separations smaller than the donor Bohr radius, a strong modification of the SPL spectrum is observed. This effect is discussed in terms of modification of the acceptor ground state induced by the interaction with a neighbouring donor centre.
Hydrogen passivation of the SiGa donor in GaP
Authors: Ulrici W. , Clerjaud B. , Côte D.
Published: December 2002

In LEC‐grown GaP doped with silicon, two vibrational absorption lines are measured at 2175.1 and 2190.3 cm–1 (T = 7 K). These lines are due to H stretching modes where hydrogen passivates SiGa donors. Uniaxial stress experiments show that the SiGa complex responsible for the 2175.1 cm–1 line has trigonal symmetry and is the isolated passivated SiGa. The complex creating the 2190.3 cm–1 line has the symmetry Cs and contains additionally a BGa with the four constituents located in an {110} mirror plane. Therefore, also the structure of the group‐IV donohydrogen complexes is in GaP different from that observed in GaAs.
Shallow donor activity of S–H, Se–H, and Te–H complexes in silicon
Authors: Coutinho J. , Torres V.J.B. , Jones R. , Resende A. , Briddon P.R.
Published: December 2002

The interaction of a single hydrogen atom with a substitutional chalcogen impurity (S, Se, or Te) is investigated by ab‐initio modeling. In Se–H and Te–H complexes, the proton sits at an anti‐bonding site relative to a nearest neighbor silicon atom, but two competitive trigonal structures for S–H are found. All the singly hydrogenated complexes are predicted to behave as shallow donors with levels lying above those of the substitutional S, Se and Te double donors. A comparison of our results with experimental data suggests an assignment of the Si‐NL60 EPR signal to Se–H.
Properties of zinc acceptor and exciton bound to zinc in ammonothermal GaN
Authors: Korona K. P. , Doradziński R. , Palczewska M. , Pietras M. , Kamińska M. , Kuhl J.
Published: December 2002

Time‐resolved photoluminescence (TRPL) and electron paramagnetic resonance (EPR) studies of Zn acceptor in GaN are presented. The EPR measurements revealed a strong line, which was ascribed to either an isolated Zn acceptor or to a complex defect involving Zn. Two photoluminescence lines were analyzed: the well‐known line of exciton bound to Mg acceptor, AMgX at 3.467 eV (8 K), and a new line that was ascribed to exciton bound to Zn acceptor, AZnX at 3.456 eV. The radiative decay time of the AZnX was about 1.4 ns, which was longer than that of the AMgX line. The longer radiative lifetime suggested a smaller radius of the AZnX wave function.
Effect of nitrate and phosphate concentration on production of microcystins by Microcystis viridis NIES 102
Authors: Kameyama K. , Sugiura N. , Isoda H. , Inamori Y. , Maekawa T.
Published: December 2002

The effects of nitrate and phosphate concentrations on the production of three microcystins, namely, types LR, RR and YR by Microcystis viridis NIES 102, were determined in batch culture experiments at in situ level concentrations. The yield of microcystin-RR during the exponential growth phase increased favorably in nitrate concentrations ranging from 0.2 to 0.8 mg l−1 of NO3-N. The effect plateaued at 1.0 mg l−1. This tendency was similar to the effect of nitrate on the specific growth rate. There was no significant correlation between the amounts of intracellular microcystins at exponential growth phase and nitrate concentrations. On the other hand, the specific growth rate was constant regardless of the phosphate concentrations. However, the yield of the three types of microcystins in the culture broth and the amounts of intracellular microcystins decreased with increasing the phosphate concentration. Furthermore, it was found that the correlation between total yield of microcystins (LR, RR and YR) and the ratio of microcystins during the exponential growth phase showed almost constant values, as follows: microcystin LR (0.24), RR (0.66) and YR (0.10).
Dequalinium
Authors: Rosenbaum Tamara , Islas León D. , Carlson Anne E. , Gordon Sharona E.
Published: December 2002

Cyclic nucleotide–gated (CNG) channels have been shown to be blocked by diltiazem, tetracaine, polyamines, toxins, divalent cations, and other compounds. Dequalinium is an organic divalent cation which suppresses the rat small conductance Ca2+-activated K+ channel 2 (rSK2) and the activity of protein kinase C. In this study, we have tested the ability of dequalinium to block CNGA1 channels and heteromeric CNGA1+CNGB1 channels. When applied to the intracellular side of inside-out excised patches from Xenopus oocytes, dequalinium blocks CNGA1 channels with a K1/2 ≈ 190 nM and CNGA1+CNGB1 channels with a K1/2 ≈ 385 nM, at 0 mV. This block occurs in a state-independent fashion, and is voltage dependent with a zδ ≈ 1. Our data also demonstrate that dequalinium interacts with the permeant ion probably because it occupies a binding site in the ion conducting pathway. Dequalinium applied to the extracellular surface also produced block, but with a voltage dependence that suggests it crosses the membrane to block from the inside. We also show that at the single-channel level, dequalinium is a slow blocker that does not change the unitary conductance of CNGA1 channels. Thus, dequalinium should be a useful tool for studying permeation and gating properties of CNG channels.
Liposomal clodronate as a novel agent for treating autoimmune hemolytic anemia in a mouse model
Authors: Jordan Michael B. , van Rooijen Nico , Izui Shozo , Kappler John , Marrack Philippa
Published: December 2002

Autoimmune hemolytic anemia (AIHA) is a disease in which autoantibodies against red blood cells (RBCs) lead to their premature destruction. Most clinically significant autoantibodies are of the immunoglobulin G (IgG) type, which leads primarily to the uptake and destruction of RBCs by splenic and hepatic macrophages. Therapies such as corticosteroids and splenectomy are directed at interfering with this process. Liposomally encapsulated clodronate (dichloromethylene diphosphonate) has previously been found to be a potent antimacrophage agent. It selectively depletes animals of macrophages within 24 hours of administration by inducing apoptosis in these cells. Therefore, we hypothesized that liposomal clodronate would be a useful agent for treating AIHA. We tested this hypothesis in a mouse model of AIHA in which animals were given either anti-RBC antibodies or preopsonized RBCs. In either case, liposomal clodronate substantially decreased RBC destruction. This drug formulation was effective within hours by first blocking and then depleting phagocytic macrophages, and its action lasted for 1 to 2 weeks. Thus, in AIHA, liposomal clodronate therapy may act like a temporary, medicinal splenectomy. As such, it may prove useful in situations where rapid response to therapy is critical or other medical therapies are inadequate.
Tumor necrosis factor-alpha expressed constitutively in erythroid cells or induced by erythropoietin has negative and stimulatory roles in normal erythropoiesis and erythroleukemia
Authors: Jacobs-Helber Sarah M. , Roh Kwan-ho , Bailey Daniel , Dessypris Emmanuel N. , Ryan John J. , Chen Jingchun , Wickrema Amittha , Barber Dwayne L. , Dent Paul , Sawyer Stephen T.
Published: December 2002

Binding of erythropoietin (EPO) to its receptor (EPOR) on erythroid cells induces the activation of numerous signal transduction pathways, including the mitogen-activated protein kinase Jun-N-terminal kinase (JNK). In an effort to understand the regulation of EPO-induced proliferation and JNK activation, we have examined the role of potential autocrine factors in the proliferation of the murine erythroleukemia cell line HCD57. We report here that treatment of these cells with EPO induced the expression and secretion of tumor necrosis factor alpha (TNF-α). EPO-dependent proliferation was reduced by the addition of neutralizing antibodies to TNF-α, and exogenously added TNF-α induced proliferation of HCD57 cells. EPO also could induce TNF-α expression in BAF3 and DA3 myeloid cells ectopically expressing EPOR. Addition of TNF-α activated JNK in HCD57 cells, and the activity of JNK was partially inhibited by addition of a TNF-α neutralizing antibody. Primary human and murine erythroid progenitors expressed TNF-α in either an EPO-dependent or constitutive manner. However, TNF-α had an inhibitory effect on both immature primary human and murine cells, suggestive that the proliferative effects of TNF-α may be limited to erythroleukemic cells. This study suggests a novel role for autocrine TNF-α expression in the proliferation of erythroleukemia cells that is distinct from the effect of TNF-α in normal erythropoiesis.