bluuebunny/crossref_metadata_2025_split huggingface dataset:
Consistency of aggressive temperament in domestic pigs: The effects of social experience and social disruption
Authors: D'Eath Richard B. 
Published: September 2004

AbstractResident‐intruder (R‐I) tests can be used to measure the aggressive temperament of domestic pigs (Sus scrofa), and have previously been shown to predict the severity and persistence of aggression when unfamiliar pigs are mixed. To study the consistency of individual differences in aggressiveness over time, 112 pigs (eight from each of fourteen litters) were given two R‐I tests at each of three ages (46, 80, and 113 days). Pigs were R‐I tested singly in an arena within the home pen, where a smaller unfamiliar intruder pig was introduced to a resident pig. Latency to the first attack by the resident was recorded, and the test was stopped as soon as an attack occurred, otherwise the test lasted five minutes. Pigs from eight of the litters used here had been allowed to mix with another litter prior to weaning (days 10–30; socialised), while pigs in six litters remained in littermate groups (control). To determine whether consistency would survive the effects of social disruption, pigs were mixed into new groups on two occasions between the first and second test, then remained in these groups until the third test. Evidence of consistency was found, despite the social disruption. Socialised pigs were more aggressive than controls, females were more aggressive than males, and certain litters were more aggressive than others. After adjusting for these, consistent differences between individuals were still evident. Consistency was higher between the second and third tests compared to the first and second, possibly because of stable group membership or the effects of age or experience. In support of the idea that social experience improves consistency, socialised pigs were more consistent than controls throughout. Evidence of consistent individual differences in aggressive temperament suggests that breeding or changes to early life experiences could have a long‐lasting influence on aggressive behaviour in pigs. Aggr. Behav. 30:435–448, 2004. © 2004 Wiley‐Liss, Inc.
Cognitive load and the imagination effect
Authors: Leahy Wayne , Sweller John 
Published: September 2004

AbstractWhen presented with a procedure or concept to learn, imagining the procedure or concept may be an effective instructional technique compared to conventional studying, thus generating an imagination effect. However, it was hypothesized that the importance of learning through imagining as an instructional technique depends on modes of presentation. Experiment 1 tested adults studying or imagining contour maps as participants and was designed to verify the generality of the imagination effect. Imagination instructions were superior to study instructions on subsequent test questions. Experiment 2 further investigated the effect by comparing much younger students (Grade 4), studying or imagining temperature/time graphs presented in either a split‐attention (spatially separated diagram and text) or an integrated (spatially combined diagram and text) format. Results on a subsequent test indicated that the Grade 4 students found imagining beneficial to their learning, compared with studying the material but the effect was only obtained using an integrated rather than a split‐attention format. Experiment 3 was conducted to obtain verbal protocols from Grade 4 imagination and study groups using the same instructional materials to throw light on the cognitive mechanisms behind the imagination effect. Copyright © 2004 John Wiley & Sons, Ltd.
A tuning algorithm for multivariable restricted structure control systems using subspace identification
Authors: Sánchez A. , Katebi M. R. , Johnson M. A. 
Published: September 2004

AbstractThis paper presents a new method to design a restricted structure controller driving a multivariable plant using subspace identification methods. The algorithm employs data collected from closed‐loop operation to identify an open‐loop model of the plant using subspace identification. The method also requires knowledge of the first N impulse responses from the controller. The multivariable controller parameters are calculated by minimising a finite horizon LQG criterion subject to nonlinear constraints. Three simulation case studies are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Genetics of atrioventricular conduction disease in humans
Authors: Benson D. Woodrow 
Published: September 2004

AbstractAtrioventricular (AV) conduction disease (block) describes impairment of the electrical continuity between the atria and ventricles. Classification of AV block has utilized biophysical characteristics, usually the extent (first, second, or third degree) and site of block (above or below His bundle recording site). The genetic significance of this classification is unknown. In young patients, AV block may result from injury or be the major cardiac manifestation of neuromuscular disease. However, in some cases, AV block has unknown or idiopathic cause. In such cases, familial clustering has been noted and published pedigrees show autosomal dominant inheritance; associated heart disease is common (e.g., congenital heart malformation, cardiomyopathy). The latter finding is not surprising given the common origin of working myocytes and specialized conduction system elements. Using genetic models incorporating reduced penetrance (disease absence in some individuals with disease gene), variable expressivity (individuals with disease gene have different phenotypes), and genetic heterogeneity (similar phenotypes, different genetic cause), molecular genetic causes of AV block are being identified. Mutations identified in genes with diverse functions (transcription, excitability, and energy homeostasis) for the first time provide the means to assess risk and offer insight into the molecular basis of this important clinical condition previously defined only by biophysical characteristics. © 2004 Wiley‐Liss, Inc.
Evaluation of mechanisms of azinphos‐methyl resistance in the codling moth Cydia pomonella (L.)
Authors: Reuveny Haim , Cohen Ephraim 
Published: September 2004

AbstractResistance of the codling moth Cydia pomonella (L.) to azinphos‐methyl is not based on enhanced detoxifying enzymes like oxidation mediated by mixed function oxidases or by glutathione S‐transferases. Synergism by S,S,S‐tributylphosphoro‐trithioate was evident, but the overall activity of general esterases using p‐nitrophenyl acetate as the substrate was similar in resistant and susceptible insects. In comparison to acetylcholinesterase (AChE) from susceptible adult codling moth, the enzyme of insects resistant to azinphos‐methyl has low affinities (higher Km values) to the substrates acetylthiocholine (ATCh) and propionylthiocholine. This difference indicates a possible amino acid alteration at the catalytic or anionic binding sites of the resistant enzyme. Inhibition studies revealed no apparent differences in sensitivity of AChE enzymes from resistant and susceptible moths to organophosphorus compounds (OPs), carbamate insecticides and quaternary ammonium ligands. MEPQ (7‐Methylethoxyphosphinyloxy)‐1‐methylquinolinium) is the most powerful OP inhibitor acting at a nM range, while chlopyrifos oxon, azinphos‐methyl oxon and paraoxon are less inhibitory by 22.9, 82.3 and 475 fold, respectively.The codling moth AChE is a typical enzyme that displays substrate inhibition by ATCh, negligible hydrolysis of butyrylthiocholine, very high sensitivity to the bisquaternary ammonium compound BW284c51 and it is not inhibited by the powerful butyrylcholinesterase inhibitor iso‐OMPA. Of the three carbamates examined, only carbaryl was inhibitory at the mM range while pirimicarb and aldicarb were inactive. Of the quaternary ammonium ligands (except for the powerful BW284c51), edrophonium and decamethonium displayed appreciable inhibition rates, while d‐tubocuraine was practically inactive. Arch. Insect Biochem. Physiol. 57:92–100, 2004. © 2004 Wiley‐Liss, Inc.
A validated method for analysis of chromium picolinate in nutraceuticals by reversed phase high performance liquid chromatography
Authors: Koll Michael , Hoenen Hubertus , Aboul‐Enein Hassan Y. 
Published: September 2004

AbstractA validated high performance liquid chromatographic method was developed for the determination of chromium picolinate in pharmaceutical dosage forms. The analysis was performed at room temperature using a reversed‐phase Supelcosil LC‐18 (250 × 4.6 mm, 5 µm) column. The mobile phase consisted of acetonitrile:water (40:60 v/v) at a ﬂow rate of 0.8 mL/min. The UV‐detector was set at 264 nm. The developed method showed a good linear relationship in the concentration range from 0.125 to 12.5 µg/mL with a correlation coefﬁcient from 0.999. The limit of detection and limit of quantiﬁcation were 0.091 and 0.181 µg/mL, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of testosterone on polyunsaturated fatty acid biosynthesis in Sertoli cells in culture
Authors: Hurtado de Catalfo G. E. , de Gómez Dumm I. N. T. 
Published: September 2004

AbstractSertoli cells play a central role in spermatogenesis, its development and regulation. They are target cells for androgen action in the seminiferous tubules. The Sertoli cell is considered to be the most important cell type in the testis with regard to essential fatty acid metabolism. We studied the response to testosterone of cultured Sertoli cells from immature rats by determining the fatty acid composition of total cellular lipids as well as by the biosynthesis of polyunsaturated fatty acids. Fatty acid methyl esters were analysed by gas liquid chromatography and radiochromatography. Two doses of testosterone were tested (150 and 300 ng ml−1). Significant differences were found in fatty acids derived from total cellular lipids after 8 days in culture in the presence of testosterone (300 ng ml−1, for 48 h). Compared to controls, the hormone produced a significant increase of 16:1 and 18:1 n‐9, and of 18:2 n‐6, and a decrease of 20:4 and 22:5 n‐6 in total cellular lipids. The decrease in the n‐6 fatty acid ratios 20:4/20:3, 20:4/18:2 and 24:5/24:4, and the increase in 18:1n‐9/18:0 and 16:1n‐9/16:0 ratios were taken as an indirect signal of testosterone effects on Δ5, Δ6 and Δ9 desaturase activities. The drop in Δ5 and Δ6 desaturase activities was corroborated by analysing the transformation of [1‐14C]20:3 n‐6 into its higher homologues. We concluded that testosterone modifies the fatty acid pattern of cultured Sertoli cells, and this hormone is involved in polyunsaturated fatty acid biosynthesis, modulating Δ5 and Δ6 desaturases activity. Copyright © 2004 John Wiley & Sons, Ltd.
Studies on the endogenous phospholipids of mammalian kidney and their in vitro hydrolysis by endogenous phospholipases: a thin layer chromatographic and densitometric study
Authors: Helmy Fatma M. , Hassanein Mohamed , Juracka Amal 
Published: September 2004

AbstractThe phosphoglycerides profile of six species of mammalian kidney (guinea pig, pig, cat, dog, mouse and rat) and their in vitro response to the endogenous phospholipases were determined by TLC technology in conjunction with densitometric measurements. Changes in their phospholipids profile subsequent to in vitro incubation of whole tissue homogenate of these kidneys for 60 min, at pH 7.4, 38°C, and prior to phospholipids extraction have shown that the deacylation of the endogenous cardiolipin (CL) is the most prevalent lipolytic event of all mammalian kidneys studied. Concurrent with the deacylation of CL, there was also formation of monolysocardiolipin (MLCL) and a reduction in CL level. To a much lesser extent, lyso alkenyl phosphatidyl ethanolamine (LPE) was also produced concomitant with a decrease of the endogenous alkenyl phosphatidyl ethanolamine (PE) level. The deacylation of PE plasmalogen to its lyso form confirms the action of endogenous PLA2 releasing sn‐2 fatty acids. Copyright © 2004 John Wiley & Sons, Ltd.
Ultrastructural determination of gingival Langerhans cells in alloxan‐induced diabetic rats
Authors: Özsoy Nesrin , Gül Nursel , Bostanci Hamit , Ayvali Cevat 
Published: September 2004

AbstractThe ultrastructure of Langerhans cells has not been fully investigated in diabetes‐associated gingival tissues. The present study was carried out to investigate the ultrastructure of gingival Langerhans cells in alloxan‐induced diabetic rats. Gingival biopsies were obtained from 22 diabetic and 18 control rats. Langerhans cells were observed by transmission electron microscopy (TEM) in the basal layers of healthy oral epithelium. On rare occasions, Langerhans cells were found in the suprabasal layers of the oral epithelium. Langerhans cells in the oral epithelium of diabetic rats were seen in the basal and suprabasal layers. Usually, Langerhans cells had clear cytoplasm and convoluted or indented nuclei and few or no specific granules. The clear cytoplasm contained mitochondria, lysosomes and a small number of rough‐surfaced endoplasmic reticulum regions, but it lacked tonofilament. Occasionally, centrioles were also observed in the cytoplasm. The membrane of Langerhans cells had no junctional complexes such as desmosomes. In diabetic rats, Langerhans cell precursors were developed into specific granule‐bearing cells. Both Langerhans cells and their granules were more frequent in the gingiva of diabetic rats than in the control group. These data suggest that Langerhans cells play an important role in explaining the pathogenesis and development of diabetic gingivitis. Copyright © 2004 John Wiley & Sons, Ltd.
The long‐term effect of mesh bioprosthesis in inguinal hernia repair on testicular nitric oxide metabolism and apoptosis in rat testis
Authors: Taneli Fatma , Aydede Hasan , Vatansever Seda , Ulman Cevval , Ari Zeki , Uyanık Bekir Sami 
Published: September 2004

AbstractPolypropylene mesh is the most widely used material in inguinal hernia repair. Although polypropylene mesh is known as an inert material, it is experimentally proven that mesh generates a chronic inflammatory tissue reaction. The aim of the present study was to investigate the long‐term effects of polypropylene mesh material used in inguinal hernia operations on testicular function, testicular nitric oxide (NO) metabolism and germ cell‐specific apoptosis in rats. The study comprised 40 male rats that were randomly allocated into two groups. In group 1, the left spermatic cord was elevated and a 0.5 × 1 cm polypropylene mesh was placed behind the left inguinal spermatic cord and group 2 consisted of the sham‐operated controls. Blood samples were taken at 6 months preoperatively and postoperatively after to assess luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels for hormonal evaluation. Testicular NO was evaluated by the Griess method, apoptosis by a TUNEL method and inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) expressions by immunohistochemical staining. Mild ( + ) eNOS expression was observed in all specimens. Mild ( + ) iNOS expression was only detected in ipsilateral testis of the mesh‐implanted study group. Apoptotic cells were not detected in any samples. We are of the opinion that long‐term polypropylene mesh implantation has no effect on testicular hormonal function and only a limited effect on nitric oxide levels and this effect is not sufficient to cause apoptosis in testis that could lead to infertility. It seems that mesh implantation is a reliable method in inguinal hernia repair; however, further work is required by more sensitive methods to fully elucidate the potential testicular damage. Copyright © 2004 John Wiley & Sons, Ltd.
Comparative studies of the endogenous phospholipids and their in vitro hydrolysis by endogenous phospholipases of various tissues from 7‐day‐old chicks: a thin layer chromatographic and densitometric analysis
Authors: Helmy Fatma M. 
Published: September 2004

AbstractThe phospholipid profiles of heart, kidney, and pectoral muscle of 7‐day‐old chicks and their in vitro response to the endogenous lipolytic enzymes (mainly in the phospholipase group) at pH 7.4 and 38°C for 60 min were analysed by TLC technology and densitometry. The noticeable preferential deacylation of cardiolipin (CL) as detected by the formation of monolysocardiolipin (MLCL) and concurrent reduction of CL level were the most prevalent lipolytic events of chick cardiac muscle, but the least prevalent in chick pectoral muscle. Deacylation of ethanolamine plasmalogen (PE) as revealed by the formation of the corresponding lyso alkenyl derivative was also prominent in cardiac muscle, but much less so in kidney and none at all was detected in pectoral muscle. The level of sphingomyelin (SM) was much higher in kidney than heart and pectoral muscle. Following in vitro incubation, the reduction in the level of SM and the high level of ceramide (Cer) production were most conspicuous in kidney, less in cardiac muscle and least in pectoral muscle. The hydrolysis of PE and SM confirm the action of endogenous PLA2 and endogenous sphingomyelinase on PE and SM respectively. These data clearly illustrate the differential response of the endogenous substrates (phospholipids) to the endogenous phospholipases of the tissues studied and are probably related to their physiological activities in vivo. Copyright © 2004 John Wiley & Sons, Ltd.
Cytochrome P4501A1 polymorphisms in the Amerindian and Mestizo populations of Mexico
Authors: Fragoso José Manuel , Juárez‐Cedillo Teresa , Hernández‐Pacheco Guadalupe , Ramírez Erick , Zuñiga Joaquín , Izaguirre Raul , de la Peña Aurora , Granados Julio , Vargas‐Alarcón Gilberto 
Published: September 2004

AbstractSeveral polymorphisms in the CYP1A1 locus have been identified and their genotypes appear to exhibit population frequencies that depend on ethnicity. We studied two CYP1A1 polymorphic sites (position 4889 and 6235) in a group of 212 unrelated healthy individuals belonging to three different Mexican populations (106 Mexican Mestizos, 52 Teenek and 54 Mayos). Comparison among Mexican populations showed increased frequency of the *Ile allele (A on position 4889) in Mexican Mestizos when compared to Amerindians (p < 0.05). The analysis of position 6235 showed increased frequencies of *m2 (C in this position) allele in Teenek when compared to Mestizos and Mayos (p < 0.05) and of *m2/*m2 genotype when compared to Mestizos (p < 0.05). Amerindian populations (from Mexico and South America) presented the lowest frequencies of *Ile (position 4889) and *m1 (position 6235) alleles, however these frequencies vary according to the ethnic group studied. Mexican Amerindian groups together with other South Amerindian populations showed the highest frequencies for *Val at position 4889 and the *m2 allele at position 6235. The present study corroborates the high frequencies of*Val and *m2 alleles in the Amerindian populations and detects some differences between Mexican populations that correlate with linguistic differences. Our data could be helpful in understanding the distribution of these polymorphisms and in clarifying their roles as genetic and evolution markers in Amerindian populations. Copyright © 2004 John Wiley & Sons, Ltd.
CD147 and matrix metalloproteinase‐2 protein expression as significant prognostic factors in esophageal squamous cell carcinoma
Authors: Ishibashi Yoshio , Matsumoto Tomoe , Niwa Mikio , Suzuki Yutaka , Omura Nobuo , Hanyu Nobuyoshi , Nakada Koji , Yanaga Katsuhiko , Yamada Kyosuke , Ohkawa Kiyoshi , Kawakami Makio , Urashima Mitsuyoshi 
Published: September 2004

AbstractBACKGROUNDThe authors investigated whether the presence of matrix metalloproteinase‐2 (MMP‐2) and its inducer, CD147, in cancerous esophageal lesions and surrounding tissue might help to predict patient prognosis.METHODSTissue samples from 101 patients with esophageal squamous cell carcinoma were stained with anti‐CD147 and anti–MMP‐2 antibodies for immunohistochemical analysis.RESULTSCD147 was expressed in cancerous and dysplastic lesions, but not in normal tissue. In contrast, MMP‐2 was detected mainly in normal interstitial tissue adjacent to cancerous lesions, but it was detected also in cancerous lesions in some patients. Pathologic findings demonstrated that the intensity of MMP‐2 staining in normal tissue was associated positively with the depth of tumor infiltration and the stage of disease, whereas MMP‐2 staining in cancerous tissue was associated positively with vascular and lymphatic vessel invasion as well as with immature differentiation of cancer cells. Using a proportional hazard model, including information on CD147 staining patterns within cancerous lesions along with clinical cancer staging, improved the accuracy of predicting patient prognosis.CONCLUSIONSThese results suggested that measurement of CD147 and MMP‐2 expression with simple immunohistochemical staining may enhance further the understanding of the pathophysiology of invading tumor cells and, when used in combination with cancer staging, may increase the ability of investigators to predict prognosis in patients with esophageal squamous cell carcinoma. Cancer 2004. © 2004 American Cancer Society.
Femtosecond Pump‐Probe Measurements of Solvation by Hydrogen‐Bonding Interactions
Authors: Pines Ehud , Pines Dina , Ma Ying‐Zhong , Fleming Graham R. 
Published: September 2004

AbstractAn additional ultrafast blue shift in the transient absorption spectra of hydrogen‐bonding complexes of a strong photoacid, 8‐hydroxypyrene 1,3,6‐trisdimethylsulfonamide (HPTA), over the solvation response of the uncomplexed HPTA and also over that of the methoxy derivative of the photoacid (MPTA) in the presence of the hydrogen‐bonding base was observed on optical excitation of the photoacid. The additional 55±10 fs solvation response was found to be about 35 % and 19 % of the total C(t) of HPTA in dichloromethane (DCM) when it was hydrogen‐bonded to dimethylsulfoxide (DMSO) and dioxane, respectively, and about 29 % of the total C(t) of HPTA in dichloroethane (DCE) when it was hydrogen‐bonded to DMSO. We have assigned this additional dynamic spectral shift to a transient change in the hydrogen bond (OH⋅⋅⋅O) that links HPTA to the complexing base, after the electronic excitation of the photoacid.
The Effect of Ge Incorporation on the Brønsted Acidity of ZSM‐5
Authors: van de Water Leon G. A. , Zwijnenburg Martijn A. , Sloof Willem G. , van der Waal Jan C. , Jansen Jacobus C. , Maschmeyer Thomas 
Published: September 2004

AbstractThe effect of the isomorphous substitution of some of the Si atoms in ZSM‐5 by Ge atoms on the Brønsted acid strength has been investigated by i) DFT calculations on cluster models of the formula ((HO)3SiO)3‐Al‐O(H)‐T‐(OSi(OH)3)3, with T=Si or Ge, and ((HO)3SiO)3‐Al‐O(H)‐Si‐(OGe(OH)3)(OSi(OH)3)2, ii) a 31P NMR study of zeolite samples contacted with trimethyl phosphine oxide probe molecules and iii) a X‐ray photoelectron spectroscopy (XPS) study of ZSM‐5 and Ge‐ZSM‐5 samples. The calculations reveal that the effect of Ge incorporation on the framework acidity strongly depends on the degree of substitution and on the exact T‐atom positions that are occupied by Ge. High Ge concentrations allow for enhanced stabilisation of the deprotonated Ge‐ZSM‐5 through structural relaxation, resulting in a slightly higher acidity as compared to ZSM‐5. This structural relaxation is not achievable in Ge‐ZSM‐5 with a low Ge content, which therefore has a slightly lower acidity than ZSM‐5. The NMR study indicates no difference between the Brønsted acidity of ZSM‐5(47) and Ge(0.09)ZSM‐5(36). Instead, evidence for the presence of a substantial amount of GeOH groups in the Ge‐containing samples was obtained from the NMR results, which is consistent with earlier FTIR studies. The XPS results do not point to an effect of Ge on the framework acidity of ZSM‐5(47), instead, the results can be best interpreted by assuming the presence of additional GeOH and SiOH groups near the surface of the Ge(0.08)ZSM‐5(47) sample.