bluuebunny/crossref_metadata_2025 huggingface dataset:
Distributed model of peritoneal fluid absorption
Authors: Stachowska-Pietka J. , Waniewski J. , Flessner M. F. , Lindholm B.
Published: May 2006

The process of water reabsorption from the peritoneal cavity into the surrounding tissue substantially decreases the net ultrafiltration in patients on peritoneal dialysis. The goal of this study was to propose a mathematical model based on data from clinical studies and animal experiments to describe the changes in absorption rate, interstitial hydrostatic pressure, and tissue hydration caused by increased intraperitoneal pressure after the initiation of peritoneal dialysis. The model describes water transport through a deformable, porous tissue after infusion of isotonic solution into the peritoneal cavity. Blood capillary and lymphatic vessels are assumed to be uniformly distributed within the tissue. Starling's law is applied for a description of fluid transport through the capillary wall, and the transport within the interstitium is modeled by Darcy's law. Transport parameters such as interstitial fluid volume ratio, tissue hydraulic conductance, and lymphatic absorption in the tissue are dependent on local interstitial pressure. Numerical simulations show the strong dependence of fluid absorption and tissue hydration on the values of intraperitoneal pressure. Our results predict that in the steady state only ∼20–40% of the fluid that flows into the tissue from the peritoneal cavity is absorbed by the lymphatics situated in the tissue, whereas the larger (60–80%) part of the fluid is absorbed by the blood capillaries.
De novo ICAM-1 synthesis in the mouse lung: model of assessment of protein expression in lungs
Authors: Vogel Stephen M. , Orrington-Myers Janie , Broman Michael , Malik Asrar B.
Published: May 2006

Because most studies addressing the regulatory mechanisms of intercellular adhesion molecule (ICAM)-1 expression have used cultured endothelial cells, we set out to develop an isolated mouse lung preparation to study gene and protein expression in its proper cellular context in the organ. Lungs from CD1 mice were isolated and perfused (2 ml/min, 37°C) with a recirculating volume of RPMI 1640 solution supplemented with 3 g/100 ml albumin. Lungs maintained their isogravimetric state for 4 h. Tumor necrosis factor (TNF-α; 2,000 U/ml) was added to the perfusate for 0.5, 1, 2, or 3.5 h to induce ICAM-1 expression or lungs received no treatment (control). After quick-freezing the lungs using liquid nitrogen at different time points, the prepared tissue homogenates were analyzed for ICAM-1 protein expression by Western blotting and NF-κB activation by electrophoretic mobility shift assay. TNF-α caused a progressive increase in NF-κB activity after 0.5 h and ICAM-1 protein expression two- to threefold of basal after 2 h. Untreated lungs expressed a low and constant level of ICAM-1 between 0 and 3.5 h. TNF-α failed to induce NF-κB activation and ICAM-1 expression in lungs of NADPH oxidase-deficient mice lacking p47phox. We disaggregated mouse lungs using collagenase and stained the cells for ICAM-1 and VE-cadherin (used as an endothelial marker) to assess the in situ endothelial-specific expression of ICAM-1. We observed that TNF-α challenge resulted in increased ICAM-1 expression in endothelial cells freshly isolated from lungs. These data show the role of NADPH oxidase-derived oxidant signaling in the mechanism of NF-κB activation and ICAM-1 expression in mouse lung endothelial cells. Moreover, the general method presented herein has potential value in assessing mechanisms of gene and protein expression in the isolated-perfused mouse lung model.
Classification of DNA methylation patterns in tumor cell genomes using a CpG island microarray
Authors: Adrien L.R. , Schlecht N.F. , Kawachi N. , Smith R.V. , Brandwein-Gensler M. , Massimi A. , Chen S. , Prystowsky M.B. , Childs G. , Belbin T.J.
Published: May 2006

Our group has initiated experiments to epigenetically profile CpG island hypermethylation in genomic DNA from tissue specimens of head and neck squamous cell carcinoma (HNSCC) using a microarray of 12,288 CpG island clones. Our technique, known as a methylation-specific restriction enzyme (MSRE) analysis, is a variation of the differential methylation hybridization (DMH) technique, in that it is not an array comparison of two DNA samples using methylation-specific restriction enzymes. Instead, it is a comparison of a single DNA sample’s response to a methylation-sensitive restriction enzyme (HpaII) and its corresponding methylation-insensitive isoschizomer (MspI). Estimation of the reproducibility of this microarray assay by intraclass correlation (ICC) demonstrated that in four replicate experiments for three tumor specimens, the ICC observed for a given tumor specimen ranged from 0.68 to 0.85 without filtering of data. Repeated assays achieved 87% concordance or greater for all tumors after filtering of array data by fluorescence intensity. We utilized hierarchical clustering on a population of 37 HNSCC samples to cluster tumor samples with similar DNA methylation profiles. Supervised learning techniques are now being utilized to allow us to identify associations between specific epigenetic signatures and clinical parameters. Such techniques will allow us to identify select groups of CpG island loci that could be used as epigenetic markers for both diagnosis and prognosis in HNSCC.
Increased susceptibility to maternal aneuploidy demonstrated by comparative genomic hybridization analysis of human MII oocytes and first polar bodies
Authors: Fragouli E. , Wells D. , Whalley K.M. , Mills J.A. , Faed M.J.W. , Delhanty J.D.A.
Published: May 2006

Single cell comparative genomic hybridization (CGH) was employed to extensively investigate 24 unfertilized or in vitromatured meiosis II oocytes and their corresponding first polar bodies (PBs), to determine how and whether all 23 chromosomes participate in female meiosis I errors and to accurately estimate the aneuploidy rate in the examined cells. Results were obtained for 15 oocytes and 16 PBs, representing 23 eggs (MII oocyte-PB complexes) donated from 15 patients (average age 32.2 years). Abnormalities were detected in ten eggs, giving an overall aneuploidy rate of 43.5%. In all, fourteen anomalies were scored, with the fertilized oocyte being at risk of monosomy in eight cases and at risk of trisomy in six; chromosomes of various sizes participated. CGH was able to give a comprehensive aneuploidy rate, as both absence of chromosomal material and the presence of extra copies were accurately scored. The aneuploidy mechanisms determined were: classical whole univalent non-disjunction; chromatid predivision prior to anaphase I, leading to metaphase II imbalance. There was also evidence of germinal mosaicism for a trisomic cell line. Three patients appeared to be predisposed to meiosis I errors, based on the presence of either multiple abnormalities in one or more of their examined cells, or of the same type of abnormality in all of their cells. Exclusion of these susceptible patients reduces the aneuploidy rate to 20%. Various hypotheses are put forward to explain these observations in order to stimulate research into the complex nature of female meiotic regulation.
Isolation, mapping and identification of SNPs for four genes (ACP6, CGN, ANXA9, SLC27A3) from a bovine QTL region on BTA3
Authors: Calvo J.H. , Martínez-Royo A. , Silveri L. , Floriot S. , Eggen A. , Marcos-Carcavilla A. , Serrano M.
Published: May 2006

On the basis of fine mapping of a quantitative trait loci region of BTA3 for milk fat content, an examination of the comparative map between cattle and human indicates that the annexin 9 protein gene (ANXA9) and the fatty acid transport protein type 3 gene (SLC27A3) are two strong candidate genes. The objective of the present study is to isolate, map and characterize these genes and identify polymorphisms that could be further utilized in linkage or association studies. Furthermore, two new genes which are in the same region, cingulin protein gene (CGN) and lysophosphatidic acid phosphatase protein gene (ACP6) were studied. DNA fragments (869, 1778, 1933 and 2618 bp) corresponding to partial sequences of ACP6,CGN,ANXA9 and SLC27A3 genes were isolated. Direct sequencing of PCR products amplified from different cattle breeds revealed 1, 4, 4 and 2 SNPs for ACP6, CGN,ANXA9 and SLC27A3, respectively. For ANXA9 one SNP was located in exon 5 (A→G 951) resulting in an amino acid change from histidine to arginine. Finally, ACP6,CGN,ANXA9 and SLC27A3 genes were located on chromosome 3 between ILSTS096 and BMS819 markers, in a region in which quantitative trait loci (QTL) for several milk traits have been described.
Chromosomal mechanisms underlying the karyotype evolution of the oriental voles (Muridae, Eothenomys)
Authors: Li T. , Wang J. , Su W. , Yang F.
Published: May 2006

We have investigated the karyotype relationships of two oriental voles, i.e. the Yulong vole (Eothenomys proditor, 2n = 32) and the large oriental vole (Eothenomys miletus, 2n = 56) as well as the Clarke’s vole (Microtus clarkei, 2n = 52), by a combined approach of cross-species chromosome painting and high-resolution G-banding comparison. Chromosome-specific painting probes were generated from flow-sorted chromosomes of E. proditor and hybridized onto metaphases of E. proditor, E. miletus and M. clarkei, leading to the establishment of genome-wide comparative chromosome maps. Our results demonstrate that Robertsonian translocations (centric fusions) have played a major role in the karyotype evolution of oriental voles with no obvious evidence for the involvement of tandem fusions as proposed previously and that the genome organizations of vole species are highly conserved. The comparative chromosome maps of these three vole species belonging to two phylogenetically distinct genera provide a framework for future studies on the karyotype evolution in voles.
Karyotypes of Rana tagoi Okada with diploid number 28 in the Chausu Mountains of the Minamishinshu district of Nagano Prefecture, Japan (Anura: Ranidae)
Authors: Ryuzaki M. , Nishioka M. , Kawamura T.
Published: May 2006

Karyotypes of Tago’s brown frog Rana tagoi from the Chausu mountains in Minamishinshu of Nagano Prefecture were examined by conventional Giemsa staining, C-banding and late replication (LR)-banding. Chromosome number was 2n = 28 in all cases. The 28 chromosomes consisted of four pairs (1–4) of large biarmed chromosomes, two pairs (5–6) of telocentric chromosomes and eight pairs (7–14) of small biarmed chromosomes. Chromosome pair 11 had a secondary constriction on the long arm. In females, the C-band on the long arm of chromosome pair 6 was detected in both homologs, but was absent from the arms of the homologs of chromosome pairs 5 and 9. In males, C-bands were found in the long arms of both homologs of chromosome pairs 5 and 6, were present only in one homolog of chromosome pair 5 for certain male specimens and found in only one homolog of chromosome pair 9. Specimens of R. tagoi (2n = 28) should thus have two pairs of telocentric chromosomes to provide the same number of chromosome arms, these originating quite likely from chromosome pair 1 in the 26-chromosome specimens by centric fission. Heteromorphic sex chromosomes of the XX-XY type in R. tagoi (2n = 28) in the Chausu mountains were identified. Karyotypes of tail-tip cells from a hybrid tadpole between female R. tagoi (2n = 26) from the Hinohara village in Tokyo and male R. tagoi (2n = 28) from the Chausu mountain population were examined by squash preparation. Chromosome number was 2n = 27 in all tadpoles. The 27 chromosomes consisted of one chromosome set of R. tagoi (2n = 28) and one of R. tagoi (2n = 26).
Detection of B chromosomes in interphase hemolymph nuclei from living specimens of the grasshopper Eyprepocnemis plorans
Authors: Cabrero J. , Manrique-Poyato M.I. , Camacho J.P.M.
Published: May 2006

The two most important evolutionary properties of B chromosomes are their transmission rate (which suggests their selfishness when significantly higher than 0.5) and their net effects on carrier fitness (usually negative for parasitic Bs). The study of transmission rate unavoidably requires the analysis of many controlled crosses in order to accurately measure population average transmission rate. Therefore, getting a marker closely associated to B presence is of crucial importance to alleviate the load of performing many useless crosses between lacking B individuals. After investigating several cytogenetic techniques on several tissues that may be sampled without drastically damaging live specimens of the grasshopper Eyprepocnemis plorans, we report here the excellent results provided by the CMA3 fluorescence and C-banding techniques applied to hemocyte nuclei. These cells may be easily obtained from both males and females and provide information on B presence even during the interphase stage. The two cytogenetic techniques take advantage of the heterochromatic nature of the B chromosomes, so that Bs made predominantly of ribosomal DNA are revealed by CMA3 as bright bodies in the interphase hemocytes, and Bs mostly made of satellite DNA are visualized by C-banding as intensely stained bodies in these cells.
A highly complex rea(2;3;11) and aniridia by position effect
Authors: Rivera H. , Ayala-Madrigal M.L. , Barros-Núñez J.P. , Arnaud-López L. , Maloney V. , Crolla J.A.
Published: May 2006

A two-year-old boy presenting with bilateral aniridia and psychomotor retardation had a de novo (2;3;11) highly complex rearrangement which was characterized as far as possible by means of G-banding and FISH assays with multiple probes including cosmids for the Wilms, Aniridia, Genital anomalies and Retardation (WAGR) region, alphoid repeats for chromosomes 2, 3 and 11, subtelomere probes for 2p/2q, 3p/3q and 11q and BACs for 2q32 and 3q13. We identified ∼15 breakpoints with at least three interchromosomal and three intrachromosome anomalies involving chromosome 11. Both parents had normal karyotypes and no cryptic 11p rearrangements revealed by the chromosome 11 cosmid panel. The lack of a deletion of PAX6 pointed to the direct insertion of an ∼300-kb segment involving the cosmids FO2121 and AO4160, and more specifically the insertion’s proximal breakpoint in the ∼150-kb segment between FO2121 and FAT5 (PAX6), as the responsible factor for the patient’s aniridia via a position effect resulting in functional haploinsufficiency of the PAX6 gene. This case illustrates the importance of recognizing that de novo complex chromosomal rearrangements found in patients with diverse clinical features may contribute to the phenotype, but that multiple mechanisms and higher levels of complexity may be unmasked by high resolution molecular cytogenetic studies.
Comparison of Two Commercially Available pp65 Antigenemia Tests and COBAS Amplicor CMV Monitor for Early Detection and Quantification of Episodes of Human CMV-Viremia in Transplant Recipients
Authors: May Günter , Kühn Joachim E. , Eing Bodo R.
Published: May 2006

The performance of two commercially available CMV pp65 antigenemia (AG) assays (CINA kit, Argene Biosoft, CK, and CMV Brite kit, IQ Products, CBK), and a quantitative PCR test (COBAS Amplicor CMV Monitor Test, Roche Diagnostics, CACM) was evaluated with 667 blood samples from 215 transplant recipients. The diagnostic value of the three tests was defined by their ability to detect episodes of systemic CMV activity. A test score was defined, assigning 7 virtual units (VU) for any episode detected first, 5 VU for any episode detected second, and three VU for any episode detected last. Within the evaluated collective, the following overall scores could be determined for the three assays: 45 VU for the CK, 39 for CACM and 31 for the CBK assay. We conclude from our results that (1) the CK is superior to the CBK assay in detecting episodes of CMV antigenemia, and (2) quantitative serum CMV PCR with CACM is not generally superior to pp65 antigenemia testing.
Sequential Accumulation of the Basal Core Promoter and the Precore Mutations in the Progression of Hepatitis B Virus-Related Chronic Liver Disease
Authors: Song Byung-Cheol , Cui Xiu Ji , Kim Heung Up , Cho Yoo-Kyung
Published: May 2006

Objectives: Despite the pathogenic role of the basal core promoter (BCP) and the precore mutations in chronic hepatitis B virus (HBV) infection, their role in the progression of liver disease is still controversial. We analyzed whether the accumulation of these mutations might enhance the progression of HBV-related chronic liver disease. Methods: Forty consecutive patients at each clinical status were analyzed. Clinical statuses were as follows: HBeAg-positive asymptomatic carrier (HBeAg+ ASC) (defined as HBeAg+, anti-HBe–, HBV-DNA+ by hybridization, normal ALT); inactive HBsAg carrier; chronic hepatitis B; liver cirrhosis. The genotype and the BCP/precore regions were determined by PCR using genotype specific primers and direct sequencing, respectively. Results: All patients except one were infected with genotype C. The A to T mutation at nucleotide 1762 and/or G to A mutation at nucleotide 1764 were found in 30% in HBeAg+ ASC, 65.7% in inactive HBsAg carrier, 95% in chronic hepatitis B, and 90% in liver cirrhosis (p < 0.001). The prevalence of the G to A mutation at nucleotide 1896 was 5% in HBeAg+ ASC, 22.5% in inactive HBsAg carrier, 32.5% in chronic hepatitis B, and 50% in liver cirrhosis, respectively (p < 0.001). The T to C/A mutation at nucleotide 1753 in the BCP and G to A mutation at nucleotide 1899 in the precore were more frequent in liver cirrhosis than in the other clinical statuses (p < 0.05). Conclusion: Sequential accumulation of mutations in the BCP/precore has an important role in the progression of HBV-related liver disease.
Cytomegalovirus gB Genotype and Clinical Features in Chinese Infants with Congenital Infections
Authors: Yu Zhong Sheng , Zou Chao Chun , Zheng Ji Yan , Zhao Zheng Yan
Published: May 2006

Objective: To investigate cytomegalovirus (CMV) glycoprotein B (gB) genotypes and clinical features in Chinese infants with congenital infections. Methods: Urine samples were obtained from 79 infants with human CMV infection confirmed by quantitative fluorescence polymerase chain reaction (PCR). A fragment of the gB gene was amplified by nested PCR. CMV gB genotyping was carried out by restriction fragment length polymorphism, and 24 samples of the amplified DNA fragments were verified by DNA sequencing. Results: The levels of CMV DNA in symptomatic and asymptomatic infants were 2.95 × 105 and 4.5 × 103 copies/ml, respectively, with a significant difference (p < 0.001). In all these cases, the most prevalent genotype was gB1 (50.63%), followed by gB3 (21.52%), gB2 (17.72%), and coinfection (10.13%); gB4 was not found. Moreover, gB1 was more prevalent in infants with liver damage (22/32) than in other symptomatic infants without liver damage (8/22, p = 0.019) or asymptomatic infants (10/25, p = 0.030). The homology of CMV gB in the 24 strains amplified as compared with the sequences of prototype strains in GenBank ranged from 97.06 to 99.64%. Conclusions: The restriction fragment length polymorphism analysis of CMV gB genotypes was definite and reliable. The gB1 genotype is the most prevalent in Chinese infants with congenital CMV disease, especially in those with liver damage, followed by genotypes gB3, gB2, and gB4.
Valsartan, Blood Pressure Reduction, and C-Reactive Protein
Authors: Ridker Paul M , Danielson Eleanor , Rifai Nader , Glynn Robert J.
Published: May 2006

Increased levels of high-sensitivity C-reactive protein (hsCRP) are associated with incident hypertension as well as cardiovascular events, and angiotensin II is a potent proinflammatory mediator. However, whether angiotensin receptor blockade lowers hsCRP is uncertain. We performed a randomized trial in which 1668 patients with stage 2 hypertension were treated with 160 mg valsartan or 160/12.5 mg valsartan/hydrochlorothiazide (HCTZ) once daily for 2 weeks with forced titration to 320 mg valsartan or 320/12.5 mg valsartan/HCTZ for an additional 4 weeks. After 6 weeks, systolic blood pressure (−25 versus −18 mm Hg;
P
<0.001) and diastolic blood pressure (−14 versus −9 mm Hg;
P
<0.001) were reduced to a greater degree among those allocated to valsartan/HCTZ than to valsartan monotherapy. The median change in hsCRP was −0.12 mg/L among those allocated to valsartan compared with +0.05 mg/L among those allocated to valsartan/HCTZ, a 13.3% difference (
P
<0.001); this difference between valsartan and valsartan/HCTZ was present in all subgroups evaluated despite the fact that blood pressure reduction was greater in the combined therapy group. No relationship was observed between hsCRP reduction and blood pressure; in all analyses, the proportion of variation in change in hsCRP with valsartan monotherapy explained by change in blood pressure was <2%. Thus, in this prospective trial, valsartan reduced hsCRP levels in a manner independent of degree of blood pressure reduction. These data raise the hypothesis that angiotensin receptor blockade may have anti-inflammatory effects in addition to blood pressure–lowering effects.
Octopamine-like immunoreactivity in the brain and suboesophageal ganglion of two parasitic wasps, Cotesia glomerata and Cotesia rubecula
Authors: Bleeker Maartje , van der Zee Brenda , Smid Hans
Published: May 2006

Two closely related parasitoid wasp species, Cotesia glomerata L. and C. rubecula Marshall (Hymenoptera: Braconidae), differ in their display of associative learning and memory during host searching. As octopamine is involved in learning and memory in insects we investigated octopaminergic pathways in the brain and suboesophageal ganglion (SOG) of the two wasps. We used an anti-octopamine antibody and subsequent whole mount analysis using a confocal laserscanning microscope and pertinent software. Three groups of octopaminergic cells were located in the brain and suboesophageal ganglion. One group was located near the antennal lobes and consisted of six to eight cell bodies. A second group was located ventrally in the SOG and was most likely formed by ventral unpaired median (VUM) and VCBN (ventral cell body neurite) neurons. A third group was located in the pars intercerebralis and consisted of four to six cells. Octopamine-like immunoreactivity was furthermore present in the central body, protocerebral bridge, the SOG, antennal lobe, near the alpha and beta lobes of the mushroom bodies and in the mushroom body calyces. Due to the used methods and a high variability in staining intensity it was not possible to detect if there were any differences in the number of neurons, in arborisation patterns or in labelling intensity between the two wasp species.
Selective information use in parasitoid wasps
Authors: Thiel Andra , Hoffmeister Thomas
Published: May 2006

Foraging animals frequently have to decide where to search, what host or prey to accept, and when to leave a patch. To achieve optimal patch exploitation rates, foragers can base their decisions on information about the quality of the current patch and on an estimate of the quality of the entire habitat. The latter has rarely been studied to date. We have analysed the patch-leaving behaviour of the parasitic wasp Asobara tabida Nees (Hymenoptera: Braconidae), a solitary parasitoid of Drosophila larvae, as a function of previous experience. Females were confronted with patches containing different numbers of larvae, which were either unparasitised, or parasitised by a conspecific or larvae of different host species. Our results show that females of A. tabida were able to recognise the different qualities of the patches that we offered but that they used information about host density, host species or parasitism status of the host to different degrees during subsequent patch visits. Encounters with an unsuitable host species had a great impact on future patch-leaving decisions while the effect of host density was relatively weak. If wasps had encountered previously parasitised hosts no response could be detected during subsequent visits. We argue that the various information sources provided are of different value for the searching female and that this might explain the observed pattern of selective information use.
Olfactory learning by predatory arthropods
Authors: de Boer Jetske , Dicke Marcel
Published: May 2006

Many natural enemies of herbivorous arthropods can use herbivore-induced plant volatiles to locate their prey. The composition of herbivore-induced volatile blends is highly variable, e.g., for different plant or herbivore species. When this variation is predictable during the lifetime of an individual, learning is expected to be adaptive for natural enemies that use such information. Learning has indeed been demonstrated many times for parasitoid wasps that use herbivore-induced plant volatiles to locate their hosts. However, evidence for learning of plant volatiles by predatory mites and insects is scarce and this is the topic of the present paper. We first review previously published research that demonstrated that anthocorid bugs and the predatory mite Phytoseiulus persimilis have the capacity to learn. Next, we present new evidence for an effect of previous experiences of P. persimilis on its responses to mixtures of volatile blends, induced by prey or non-prey herbivores. Finally, we discuss the ecological relevance of olfactory learning by predatory arthropods and the need to address this topic in future research.
Gustatory response and appetitive learning in Microplitis croceipes in relation to sugar type and concentration
Authors: Wäckers Felix , Bonifay Claire , Vet Louise , Lewis Joe
Published: May 2006

Insects can be conditioned to respond to odours through associative learning. Various learning parameters, such as the rate of odour acquisition, are known to depend on the type of conditioned stimulus. Here we investigate to what extent appetitive conditioning in the parasitoid Microplitis croceipes is also affected by characteristics of the food reward (unconditioned stimulus). We tested 1 M solutions of eight sugars naturally occurring in nectar and honeydew with respect to their effect on parasitoid gustatory response and their suitability as an unconditioned stimulus in the process of associative odour learning. To test for concentration effects, a separate experiment compared parasitoid performance with 1 M and 0.25 M of sucrose, respectively. Only exposure to glucose, fructose, sucrose and melezitose enhanced feeding relative to control individuals provided water. Raffinose, mannose, galactose and melibiose did not increase or decrease consumption, indicating that these sugars are neither phagostimulants nor phagodeterrents. In the conditioning experiments, parasitoids were allowed to feed on a particular sugar solution while being exposed to the floral odour cineole. Parasitoids that had been trained with the stimulatory sugars subsequently showed a clear conditioned feeding response to the cineole. Conditioning with galactose, mannose and melibiose, on the other hand, did not lead to successful odour acquisition. Conditioning with raffinose increased the tendency of the parasitoid to exhibit a conditioned feeding response, even though this response was significantly shorter than the response following training with stimulatory sugars.The level of cineole response was not significantly influenced by the concentration of a sucrose solution, even though the 0.25 M concentration was a weaker feeding stimulant.Our findings indicate that gustatory perception is the principal unconditioned stimulus in appetitive learning. The results with raffinose indicate that postingestive feedback may be involved in food associative learning as well.
Learning in the context of sexual behaviour in insects
Authors: Dukas Reuven
Published: May 2006

There has been little ecological and evolutionary research on learning in the context of sexual behaviour in insects. The traditional views still dominating the literature are that insects are short-lived and have little opportunity to learn about courtship and mating. In this paper I challenge these views by illustrating, theoretically, that at least some insects have ample opportunities to learn in the context of sexual behaviour and that such learning may be beneficial. Some of the best empirical evidence for learning about sexual behaviour in insects is reviewed and future directions in this fruitful area of research are suggested. The role of learning in insect sexual behaviour has probably been underestimated. Such learning may have had an important effect on sexual selection and incipient speciation.
Simulation of Central Hole Drilling Process for Measurement of Residual Stresses in Isotropic, Orthotropic, and Laminated Composite Plates
Authors: Shokrieh Mahmood M. , K. Ahmad R. Ghasemi
Published: May 2006

In this article, a new method for calculating the calibration factors for measuring the residual stresses in different material systems is presented. The simulated hole drilling method can be used instead of experimental techniques. In this method the process of hole drilling, using a finite element method, is simulated. The drilling location is simulated by a finite element technique and after applying the initial load in the form of residual stresses, the elements in the hole area are deleted from the model. Then, the strain around the hole area under the strain gages are calculated. The two- and three-dimensional simulations of the hole drilling method for isotropic materials are presented. The calibration factors are calculated and compared with those available in the standards. The results show a difference of about 0.3% between the two methods. For orthotropic materials, the calibration coefficient matrix is obtained using the method presented in this study and the results are compared with theoretical values. The presented method is utilized for laminated composite materials and the calibration coefficient matrix is obtained. Different laminated composites with various lay-ups and materials are considered. Using the simulated hole drilling method and calculating the residual strains around the hole area and calculating the calibration coefficient matrix, the residual stresses due to curing process are calculated. The main advantage of the presented method is the capability to simulate the residual stresses in orthotropic materials with any degree of orthotropy. This method is able to simulate the behavior of different strain gages with different sizes and hole diameters. Simulation of the residual stresses for components and parts with complicated geometry is an application of this method.
Effect of Graphite and/or Silicon Carbide Particles Addition on the Hardness and Surface Roughness of Al-4 wt% Mg Alloy
Authors: Hassan Adel Mahmood , Tashtoush Ghassan Mousa , Al-Khalil Jafar Ahmed
Published: May 2006

In this study, the fabrication of Al-4 wt% Mg-graphite and/or silicon carbide (SiC) particulate composites is described. Composites of Al-4 wt% Mg alloy with different volume percentage values of graphite and/or SiC particles are prepared using the compocasting technique. In this technique, graphite particles and/or SiC particles are added into a semi-solid slurry during the stirring of the melt. A pitched blade stirrer is used to stir the reinforcement particles in the slurry. The slurry is then poured in a metallic mold to obtain the cast composites. The effect of the addition of graphite and/or SiC particles and porosity content on the Rockwell hardness and machinability is studied in the present work. The results show that the porosities increase with increase in particles content while Rockwell hardness decreases with increase of graphite particles. But SiC particles are found to increase the hardness of composites. Surface roughness improves with graphite content in the cast composite, and poor surface finish is obtained when SiC particles are added.
Experimental and Analytical Identification of a Delamination Using Isolated PZT Sensor and Actuator Patches
Authors: Tan Ping , Tong Liyong
Published: May 2006

Delaminations in laminated composite structures are usually invisible or difficult to detect by visual inspection, and thus, cost-effective and reliable non-destructive techniques and approaches need to be developed to detect such failures for structural health monitoring. In this study, a dynamic analytical model is developed to detect a through-the-width delamination embedded in a cantilever laminated composite beam. This beam is surface-bonded with an isolated piezoelectric lead-zirconate-titanate (PZT) sensor and a PZT actuator. The PZT actuator located near the fixed end of the composite beam is used to excite the beam system using a sinusoidal input voltage. The PZT sensor with a striped electrode pattern is bonded on the top surface of the beam section embedded with a delamination and is used to monitor the output voltages recorded from the electrode strips. To study the feasibility of the present model for delamination identification, an experimental investigation is conducted to detect an embedded delamination using this PZT sensor and actuator setup. A comparison of the first three frequencies and the output voltage distribution for the case of the first frequency between the predicted and measured results is carried out, and good agreement between them is noted. Numerical study using the present analytical model reveals that the output voltage distribution along the PZT sensor is closely related to the magnitude and frequency of the sinusoidal input voltage.
Scale and Size Effects on Dynamic Response and Damage of Glass/Epoxy Tubular Structures
Authors: Tarfaoui M. , Gning P. B. , Davies P. , Collombet F.
Published: May 2006

The impact behavior of composite materials has been extensively studied but interest has been centered on flat plates. For underwater applications, thick composite cylinders are employed and several questions must be addressed concerning the influence of accidental impact. The aim of this work is to study the dynamic response of tubular structures. Such structures find many applications but the damage upon impact is not taken into account during their dimensioning. However, at the time of their handling or in service the damage introduced by accidental impact can compromise their capacity to fulfill their function. The cylinders are thick and consist of epoxy matrix and glass fiber reinforcement. After having observed the nature of the damage related to the static and dynamic loading, the scale and size effects on dynamic response and damage are examined. The studies reveal that the dynamic responses show a satisfactory correlation with predictions based on rules of similitude.
The Effect of Solid Particle Erosion on the Mechanical Properties and Fatigue Life of Fiber-reinforced Composites
Authors: Yang N. , Nayeb-Hashemi H.
Published: May 2006

The effect of solid particle erosion on the strength and fatigue properties of E-glass/epoxy composite is investigated. Solid particle erosion with SiC particles of 400–500 μm in diameter is simulated on 12-ply [45°/–45°/0°/45°/–45°/0°]S E-glass/epoxy composites with a constant particle velocity of 42.5 m/s and a solid particle to air volume ratio of 6 kg/m3 at impact angles of 90, 60, and 30° for 30, 60, 90, and 120 s. Damaged and undamaged specimens are subjected to tensile tests while monitoring their acoustic emission (AE) activity. An erosion damage parameter is defined as a function of the particle impact angle and the erosion duration to determine the residual tensile strength of the composite. Scanning electron microscope (SEM) images of the erosion-damaged specimens reveal that the same damage mechanism occurs at different impact angles. The AE stress delay parameter is used to predict the residual tensile strength of erosion-damaged composites. Tension–tension fatigue tests are performed on virgin specimens and specimens exposed to erosion damage of 60 and 90s at 90° particle impact angle to observe the effects of erosion damage on the fatigue life. A modified Basquin's equation is defined to predict the fatigue life of the erosion-damaged specimens.
Critical Void Content for Thermoset Composite Laminates
Authors: Zhan-Sheng Guo  , Ling Liu  , Bo-Ming Zhang  , Shanyi Du
Published: May 2006

An experimental program to characterize the effect of voids on the strength of composite laminates is presented. The adequacy of a fracture criterion to represent the experimental data for the effect of voids on the flexure strength, tensile strength, and interlaminar shear strength of composite laminates is assessed. The experimental program investigates the effect of different pressures and dwell times on the critical void content. Laminates produced with carbon fiber/epoxy resin unidirectional prepreg have been produced with an intentionally high void content. Short beam shear, three-point flexure, and tensile testing are used for mechanical evaluation and the results correlate to void volume fraction and ultrasonic absorption coefficient. The ultrasonic absorption coefficient is measured for all the specimens and its variation is approximately linear with the void content, corroborating previous experimental results. The effects of these factors on the strength of the composite laminates are discussed in terms of the fracture parameters involved in the fracture criterion. The critical void content is estimated for each case both in terms of void content and ultrasonic attenuation.
Effect of Fiber Arrangement on Residual Thermal Stress Distributions in a Unidirectional Composite
Authors: Jin Kyo Kook , Oh Je Hoon , Ha Sung Kyu
Published: May 2006

A three-dimensional finite element analysis is performed to investigate the effects of fiber arrangements on the residual thermal stresses in unidirectional composites of various fiber volume fractions (FVFs). The fiber arrangements include the regular fiber arrays (square and hexagonal arrays) and a random fiber array. Normal, tangential, and shear stresses at the fiber–matrix interface are first obtained using unit cells of the regular square and hexagonal fiber arrays. To simulate better real fiber arrangements, random fiber distribution is modeled and analyzed using a finite element analysis. Statistical distributions of residual thermal stresses are obtained for various FVFs and compared with the results from regular fiber arrays. The effects of constituent material properties of composites on thermal stresses are also taken into consideration. The results indicate that the random arrangement of fibers has a significant influence on residual thermal stresses especially at high FVFs. The mode stresses of the random fibers are well estimated using the square array whereas the mean stresses are better predicted from the hexagonal array. It is shown that predicted coefficients of thermal expansion are not influenced by the microstructure of composites.
Effects of an Electromagnetic Field on the Mechanical Response of Composites
Authors: Zhupanska Olesya I. , Sierakowski Robert L.
Published: May 2006

The existing experimental evidence suggests that exposure of a composite material to an electromagnetic field leads to changes in the material's strength and resistance to delamination. In this work, the mechanical response of transversely isotropic graphite/epoxy composite plates in the presence of an electromagnetic field is studied. The interacting effects of the in-plane steady and slowly varying electric current, external magnetic field, and mechanical load as well as the effects of mechanical and electrical anisotropies are investigated. It is shown that an electromagnetic field may significantly enhance or reduce the deformed state of the composite plate depending on the direction of its application and its intensity.
Experimental Study and Fabric Tensor Quantification of Microcrack Distributions in Composite Materials
Authors: Voyiadjis George Z. , Almasri Amin H.
Published: May 2006

In this study, the microcrack distributions of samples of a metal-matrix composite material (titanium aluminide (Ti-14Al-21Nb(α2)) reinforced with continuous silicon carbide (SiC) (SCS-6) fibers) are measured experimentally, and then quantified using the fabric tensor approach. The laminated composite material samples have two lay-up configurations: [0/90]s and [±45]s. These samples are tested under uniaxial tension up to different levels of loads, to understand how microcrack distributions develop with applied loads. The [±45]s samples are shown to have more microcracks and a wider range of orientations of microcracks than the [0/90]s samples. The microcracks can be divided into two categories: fiber microcracks and fiber-interface microcracks. Distributions of both types are shown to be similar in shape but different in orientation. In addition, microcrack distributions weighted by the microcrack lengths are presented. Fabric tensors of zero, second, fourth, sixth, eighth, and tenth order are used to approximate these microcrack distributions. Fabric tensors are seen to give a very good approximation when eighth or tenth-order fabric tensors are used for both fiber and fiber-interface microcrack distribution types. Finally, damage variable and damage evolution relations are derived in terms of the fabric tensor based on a thermodynamically consistent framework.
Occupational Stress Among Correctional Supervisors
Authors: Owen Stephen S.
Published: May 2006

The purpose of this research is to examine occupational stress among correctional supervisors. Although a number of studies have focused on correctional officers, the systematic study of correctional supervisor stress has been neglected. This article draws on a sample of 329 correctional supervisors in one state to provide a quantitative and qualitative examination of correctional supervisor stress. Results indicate that overall stress levels are low. Furthermore, reported levels of stress do not vary along gender, race, educational level, and institution. However, three variables are significant predictors of low levels of stress: high levels of job satisfaction, high levels of social support, and an internal locus of control. Recommendations and avenues for future inquiry are presented.
Paving the Way for Effective Reentry Practice
Authors: Pettus Carrie A. , Severson Margaret
Published: May 2006

In 2002, 69 sites were awarded funding under the Federal Partner's Serious and Violent Offender Reentry Initiative. This initiative calls for each site to design and implement an efficacious three-part program for the successful reintegration of offenders returning from prison into communities across the United States. The Kansas Department of Corrections and the University of Kansas worked together to design, implement, and evaluate the Kansas program, building into it a boundary spanner: that person who works within and between systems to effect integrated system change. This article explores the role of the boundary spanner in confronting the 21st-century challenges facing corrections and communities. A look at how boundary spanning in Kansas is helping to pave the way to achieving optimal systemic change illustrates its usefulness in reentry efforts.
A case of pancytopenia
Authors: Keown Patrick , Mcallister-Williams Hamish , Young Allan
Published: May 2006

Sodium valproate is a commonly used anticonvulsant, particularly in the management of childhood refractory epilepsy. There is a good literature base regarding its haematological effects in this group of patients including the potential for toxic effect on the bone marrow. Valproate is increasingly being used in the treatment of psychiatric conditions, particularly bipolar affective disorder. In this article we describe a case of pancytopenia associated with a valproate level of 166mg/l. The population of psychiatric patients is different in several ways from the population of children and young adults with epilepsy from whom the existing data comes. The psychiatric patients are older, more likely to misuse substances, more likely to take overdoses and may metabolize valproate more slowly. For these reasons it would be worthwhile investigating the relationship between valproate levels, macrocytosis, platelet counts and B12 levels in this group of patients. The results of such a study would give us a clearer understanding of what the desirable therapeutic range is for valproate in bipolar affective disorder and what, if any, monitoring should be undertaken.
The efficacy of selective serotonin reuptake inhibitors in adult social anxiety disorder: a meta-analysis of double-blind, placebo-controlled trials
Authors: Hedges Dawson W. , Brown Bruce L. , Shwalb David A. , Godfrey Kirk , Larcher A. Manja
Published: May 2006

Social anxiety disorder is associated with impairment in social and occupational functioning, significant personal distress and a possible economic burden, resulting in a reduction in quality of life. To understand better the efficacy of selective serotonin reuptake inhibitors in social anxiety disorder, randomized, double-blind, placebo-controlled trials were evaluated.

Pubmed and PsychINFO electronic databases were searched for social anxiety disorder, social phobia, selective serotonin reuptake inhibitors, citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine and sertraline. Fifteen published, randomized, double-blind, placebo-controlled trials of selective serotonin reuptake inhibitors in social anxiety disorder were identified. Design, subject number, drug and dose, trial length, rating instruments, and baseline and end point data were extracted and then verified independently by a second investigator. Effect sizes were calculated from mean changes in drug and placebo groups in the Liebowitz Social Anxiety Scale and the Sheehan Disability Scale, as well as from other scales where available. For the binary data of the Clinical Global Impression of Change scores, Θlog-odds ratios (the effect-size measure appropriate for binary data) were calculated from proportion changes.

Effect sizes for the Liebowitz Social Anxiety Scale ranged from -0.029 to 1.214. Effect sizes for the Sheehan Disability Scale ranged from 0.203 to 0.480 for work, 0.237 to 0.786 for social function, and 0.118 to 0.445 for family function. ΘThe log-odds ratios for Clinical Global Impression of Change scores ranged from 0.644 to 3.267. Consistent with previous studies, selective serotonin reuptake inhibitors appear more effective than placebo for social anxiety disorder, with improvement extending into social and occupational function.
Repeated cannabinoid exposure during perinatal, adolescent or early adult ages produces similar longlasting deficits in object recognition and reduced social interaction in rats
Authors: O'Shea Melanie , McGregor Iain S. , Mallet Paul E.
Published: May 2006

There is mounting evidence that chronic cannabis use might result in lasting neurobehavioural changes, although it remains unclear whether vulnerability diminishes with age. The current study compared the effects of cannabinoid exposure at three developmental periods on subsequent measures of memory and anxiety. Male rats aged 4 days (perinatal), 30 days (adolescent) and 56 days (young adult) were injected with vehicle or incremental doses of the cannabinoid receptor agonist CP 55940, daily for 21 consecutive days (0.15, 0.20 or 0.30mg/kg for 7 days per dose, respectively). Following a 28-day drug-free period, working memory was assessed in an object recognition task. One week later, social anxiety was assessed in a social interaction test. Two days later, generalized anxiety was assessed in an emergence test. Results revealed that CP 55940 impaired working memory and social interaction similarly at all three ages. CP 55940 had no effects in five of six emergence test measures, but a modest but significant reduction in anxiety was noted in one measure following adolescent exposure. We conclude that chronic cannabinoid exposure leads to long-term memory impairments and increased anxiety, irrespective of the age at which drug exposure occurrs.