bluuebunny/crossref_metadata_2025 huggingface dataset:
Melatonin arrests peroxynitrite‐induced tau hyperphosphorylation and the overactivation of protein kinases in rat brain
Authors: Yin Jun , Liu Ying‐Hua , Xu Ya‐Fei , Zhang Yong‐Jie , Chen Jian‐Guo , Shu Bai‐Hua , Wang Jian‐Zhi
Published: June 2006

Abstract:  The purpose of this study was to examine the in vivo effect of melatonin (MEL) on peroxynitrite‐induced tau hyperphosphorylation and the involvement of glycogen synthase kinase‐3β (GSK‐3β) and mitogen‐activated protein kinase (MAPK) families. Melatonin was injected into the right cerebroventricle of the rats 1 hr before the bilateral hippocampal injection of 3‐morpholino‐sydnonimine chloride (SIN‐1), the recognized donor of peroxynitrite. Thereafter, the phosphorylation level of tau and the activity of the kinases were analyzed. The injection of SIN‐1 induced hyperphosphorylation of tau at pS396 epitope with a concomitant activation of GSK‐3β and selective MAPK isoforms including p38α, p38β, and p38δ but not p38γ. The effect of peroxynitrite was confirmed using uric acid, a recognized scavenger of peroxynitrite. Preinjection of MEL significantly arrested the peroxynitrite‐induced hyperphosphorylation of tau and the activation of GSK‐3β and MAPKs. Melatonin also ameliorated peroxynitrite‐induced oxidative stress. We conclude that MEL can efficiently arrest peroxynitrite‐induced tau hyperphosphorylation, and the underlying mechanism may involve scavenging the reactive species and suppressing the activated GSK‐3β and p38 MAPK family.
Quantification of melatonin in phototrophic organisms
Authors: Pape Carsten , Lüning Klaus
Published: June 2006

Abstract:  Melatonin, the chief secretory product of the vertebrate pineal gland is also known to occur in numerous photoautotrophic organisms. The indoleamine is suspected to act as a transducer of photoperiodic information and/or to participate in antioxidative protection. In higher plants and other photoautotrophic organisms, contradictory results for melatonin content for samples from the same species show that further improvement of methods for reliable quantification is required. In the present study, melatonin was quantified in tomatoes, ginger and the marine green macroalga, Ulva lactuca, after extraction with three different extraction methods based on ether, acetone or perchloric acid. Melatonin was determined by enzyme‐linked immunosorbent assay (ELISA) in high‐performance liquid chromatography (HPLC)‐purified extracts. The same HPLC system used for purification of extracts was used for parallel quantifications after derivatization of melatonin under alkaline conditions in the presence of hydrogen peroxide (HPLC‐PD). Both quantification methods gave similar results with a high correlation [f(x) = 0.99x + 3.01; R2 = 0.99]. In ginger, the melatonin concentration was below 5 pg/g (fresh weight, f.w.), whereas in tomatoes about 1200 pg/g (f.w.) were found, and in the green alga, U. lactuca, approximately 12 pg/g (f.w.). Taking into account the recovery rates for synthetic melatonin added prior to extraction, no substantial differences were observed in melatonin quantification between different extraction methods. The demonstrated methods based on HPLC purification and subsequent quantification by ELISA and HPLC‐PD allow highly sensitive melatonin determinations in diverse photoautotrophic organisms with a low risk of overestimations by false‐positive results.
Family Carers of Adult Persons with Intellectual Disabilities on the Island of Ireland
Authors: Barron Steve , McConkey Roy , Mulvany Fiona
Published: June 2006

Abstract  Many families provide lifelong support to their relative with an intellectual disability. However, relatively little information is available for national populations on the characteristics of the people for whom these families care and the supports they receive or need. A database of all persons in receipt of intellectual disability services has been operating in the Republic of Ireland since 1995 and records details of those living with family carers. In Northern Ireland, regional databases provide similar information. Using both sources, data were obtained on over 12,500 people living with family carers; half of whom lived with two parents, around 30% with a lone parent, and just under 20% with another relative. More people in Northern Ireland were identified as living with family carers, which was attributed mainly to less available residential alternatives. Only a minority of carers received respite breaks and domiciliary supports although higher proportions required them. The authors conclude that family care arrangements have received relatively little attention within government policy making, and hence service provision has been largely reactive. Future research should focus on the changing needs of carers over time and how they can be better supported in their role.
Obesity and Its Related Health Problems in People with Intellectual Disabilities
Authors: Ito Jun‐ichi
Published: June 2006

Abstract  Obesity and its related health problems in people with intellectual disabilities were examined, focusing on differences related to their place of residence. The prevalence of obesity was higher in older women living in community group homes than in the same age group of women living in institutes or among the general population. Hyperglycemia, dyslipidemia, and hypertension were less common in people with intellectual disabilities, especially among people living in institutes when compared with people living in the group homes and with the general population. Abnormal liver tests and hyperuricemia were found more in younger men; these may have resulted from obesity as well as some other clinical factors related to their intellectual disabilities.
New pulsating white dwarfs in cataclysmic variables
Authors: Nilsson R. , Uthas H. , Ytre-Eide M. , Solheim J-E. , Warner B.
Published: June 2006

The number of discovered non-radially pulsating white dwarfs (WDs) in cataclysmic variables (CVs) is increasing rapidly by the aid of the Sloan Digital Sky Survey (SDSS). We performed photometric observations of two additional objects, SDSS J133941.11+484727.5 (SDSS 1339), independently discovered as a pulsator by Gänsicke et al., and SDSS J151413.72+454911.9, which we identified as a CV/ZZ Ceti hybrid. In this Letter we present the results of the remote observations of these targets performed with the Nordic Optical Telescope (NOT) during the Nordic-Baltic Research School at Moletai Observatory, and follow-up observations executed by NOT in service mode. We also present three candidates we found to be non-pulsating.

The results of our observations show that the main pulsation frequencies agree with those found in previous CV/ZZ Ceti hybrids, but specifically for SDSS 1339 the principal period differs slightly between individual observations and also from the recent independent observation by Gänsicke et al. Analysis of SDSS colour data for the small sample of pulsating and non-pulsating CV/ZZ Ceti hybrids found so far seems to indicate that the r-i colour could be a good marker for the instability strip of this class of pulsating WDs.
Differential regulation of metabolic genes in skeletal muscle during starvation and refeeding in humans
Authors: Tsintzas Kostas , Jewell Kirsty , Kamran Mo , Laithwaite David , Boonsong Tantip , Littlewood Julie , Macdonald Ian , Bennett Andrew
Published: June 2006

This study investigated the molecular alterations underlying the physiological adaptations to starvation and refeeding in human skeletal muscle. Forty‐eight hours' starvation reduced whole‐body insulin sensitivity by 42% and produced marked changes in expression of key carbohydrate (CHO) regulatory genes and proteins: SREBP1c and hexokinase II (HKII) were downregulated 2.5‐ and 5‐fold, respectively, whereas the pyruvate dexydrogenase kinase 4 (PDK4) was upregulated 4‐fold. These responses were not dependent on the phosphorylation status of Akt and FOXO1. On the other hand, starvation and the concomitant increase in circulating free fatty acids did not upregulate the expression of transcription factors and genes involved in fat metabolism. Twenty‐four hours' refeeding with a CHO‐rich diet completely reversed the changes in PDK4, HKII and SREBP1c expression in human skeletal muscle but failed to fully restore whole‐body insulin sensitivity. Thus, during starvation in healthy humans, unlike rodents, regulation of fat metabolism does not require an adaptive response at transcriptional level, but adaptive changes in gene expression are required to switch off oxidative glucose disposal. Lack of effect on key proteins in the insulin‐signalling pathway may indicate that changes in intracellular substrate availability/flux may be responsible for these adaptive changes in glucose metabolism. This may represent an important aspect of the molecular basis of the development of insulin resistance in metabolic conditions characterized by energy restriction.
Both Ca2+‐permeable and ‐impermeable AMPA receptors contribute to primary synaptic drive onto rat dorsal horn neurons
Authors: Tong Chi‐Kun , MacDermott Amy B.
Published: June 2006

Blockade of Ca2+‐permeable AMPA receptors in the rat spinal cord diminishes the development of hyperalgesia and allodynia associated with peripheral injury. Cobalt uptake studies reveal that Ca2+‐permeable AMPA receptors are expressed by some substance P receptor‐expressing (NK1R+) neurons in lamina I, as well as other neurons throughout the superficial dorsal horn. Selective elimination of NK1R+ neurons in lamina I and lamina III/IV of the dorsal horn also suppresses development of hyperalgesia and allodynia. These observations raise the possibility that Ca2+‐permeable AMPA receptors contribute to excitatory synaptic drive onto the NK1R+ neurons associated with allodynia and hyperalgesia. The first synapse in the pain pathway is the glutamatergic excitatory drive from the primary afferent fibres onto dorsal horn neurons. Therefore, we tested whether Ca2+‐permeable AMPA receptors are located on lamina I and lamina III/IV NK1R+ neurons postsynaptic to primary afferent fibres, using inward rectification and polyamine toxins for receptor identification. We examined three different populations of dorsal horn neurons; lamina I NK1R+ neurons, including projection neurons, and non‐NK1R+ (NK1R–) neurons including interneurons, and lamina III/IV NK1R+ neurons, believed to contribute to the low‐threshold mechanosensory pathway. The majority of synapses in all three groups had rectification indices less than 1.0 and greater than 0.4, indicating that the AMPA receptors at these synapses are a mixture of Ca2+‐permeable and ‐impermeable forms. Lamina III/IV NK1R+ neurons and lamina I NK1R– neurons have a significantly higher proportion of postsynaptic Ca2+‐permeable AMPA receptors than lamina I NK1R+ neurons. Thus synaptically positioned Ca2+‐permeable AMPA receptors directly contribute to low‐threshold sensory afferent drive into the dorsal horn, and can mediate afferent input onto interneurons such as GABAergic neurons. These receptors also contribute to high‐threshold primary afferent drive onto NK1R+ neurons in the superficial dorsal horn, but do so less consistently.
Maternal nutrient restriction affects properties of skeletal muscle in offspring
Authors: Zhu Mei J. , Ford Stephen P. , Means Warrie J. , Hess Bret W. , Nathanielsz Peter W. , Du Min
Published: June 2006

Maternal nutrient restriction (NR) affects fetal development with long‐term consequences on postnatal health of offspring, including predisposition to obesity and diabetes. Most studies have been conducted in fetuses in late gestation, and little information is available on the persistent impact of NR from early to mid‐gestation on properties of offspring skeletal muscle, which was the aim of this study. Pregnant ewes were subjected to 50% NR from day 28–78 of gestation and allowed to deliver. The longissimus dorsi muscle was sampled from 8‐month‐old offspring. Maternal NR during early to mid‐gestation decreased the number of myofibres in the offspring and increased the ratio of myosin IIb to other isoforms by 17.6 ± 4.9% (P < 0.05) compared with offspring of ad libitum fed ewes. Activity of carnitine palmitoyltransferase‐1, a key enzyme controlling fatty acid oxidation, was reduced by 24.7 ± 4.5% (P < 0.05) in skeletal muscle of offspring of NR ewes and would contribute to increased fat accumulation observed in offspring of NR ewes. Intramuscular triglyceride content (IMTG) was increased in skeletal muscle of NR lambs, a finding which may be linked to predisposition to diabetes in offspring of NR mothers, since enhanced IMTG predisposes to insulin resistance in skeletal muscle. Proteomic analysis by two‐dimensional gel electrophoresis demonstrated downregulation of several catabolic enzymes in 8‐month‐old offspring of NR ewes. These data demonstrate that the early to mid‐gestation period is important for skeletal muscle development. Impaired muscle development during this stage of gestation affects the number and composition of fibres in offspring which may lead to long‐term physiological consequences, including predisposition to obesity and diabetes.
Two different oxygen sensors regulate oxygen‐sensitive K+ transport in crucian carp red blood cells
Authors: Berenbrink Michael , Völkel Susanne , Koldkjær Pia , Heisler Norbert , Nikinmaa Mikko
Published: June 2006

The O2 dependence of ouabain‐independent K+ transport mechanisms has been studied by unidirectional Rb+ flux analysis in crucian carp red blood cells (RBCs). The following observations suggest that O2 activates K+–Cl− cotransport (KCC) and deactivates Na+–K+–2Cl− cotransport (NKCC) in these cells via separate O2 sensors that differ in their O2 affinity. When O2 tension (PO2) at physiological pH 7.9 was increased from 0 to 1, 4, 21 or 100 kPa, K+ (Rb+) influx was increasingly inhibited, and at 100 kPa amounted to about 30% of the value at 0 kPa. This influx was almost completely Cl− dependent at high and low PO2, as shown by substituting Cl− with nitrate or methanesulphonate. K+ (Rb+) efflux showed a similar PO2 dependence as K+ (Rb+) influx, but was about 4–5 times higher over the whole PO2 range. The combined net free energy of transmembrane ion gradients favoured net efflux of ions for both KCC and NKCC mechanisms. The KCC inhibitor dihydroindenyloxyalkanoic acid (DIOA, 0.1 mm) abolished Cl−‐dependent K+ (Rb+) influx at a PO2 of 100 kPa, but was only partially effective at low PO2 (0–1 kPa). At PO2 values between 0 and 4 kPa, K+ (Rb+) influx was further unaffected by variations in pH between 8.4 and 6.9, whereas the flux at 21 and 100 kPa was strongly reduced by pH values below 8.4. At pH 8.4, where K+ (Rb+) influx was maximal at high and low PO2, titration of K+ (Rb+) influx with the NKCC inhibitor bumetanide (1, 10 and 100 μm) revealed a highly bumetanide‐sensitive K+ (Rb+) flux pathway at low PO2, and a relative bumetanide‐insensitive pathway at high PO2. The bumetanide‐sensitive K+ (Rb+) influx pathway was activated by decreasing PO2, with a PO2 for half‐maximal activation (P50) not significantly different from the P50 for haemoglobin O2 binding. The bumetanide‐insensitive K+ (Rb+) influx pathway was activated by increasing PO2 with a P50 significantly higher than for haemoglobin O2 binding. These results are relevant for the pathologically altered O2 sensitivity of RBC ion transport in certain human haemoglobinopathies.
Viability of Dynamic Cooling Control in a Data Center
Environment
Authors: Boucher Timothy D. , Auslander David M. , Bash Cullen E. , Federspiel Clifford C. , Patel Chandrakant D.
Published: June 2006

Data center thermal management challenges have been steadily increasing over the past few years due to rack level power density increases resulting from system level compaction. These challenges have been compounded by antiquated environmental control strategies designed for low power density installations and for the worst-case heat dissipation rates in the computer systems. Current data center environmental control strategies are not energy efficient when applied to the highly dynamic, high power density data centers of the future. Current techniques control the computer room air conditioning units (CRACs) based on the return air temperature of the air—typically set near 20°C. Blowers within the CRACs are normally operated at maximum flow rate throughout the operation of the data center unless they are equipped with nonstandard variable frequency drives. At this setting the blowers typically provide significantly more airflow than is required by the equipment racks to prevent recirculation and the subsequent formation of hot spots. This strategy tends to be overly conservative and inefficient. As an example air entering a given system housed in a rack undergoes a temperature rise of 15°C due to the heat added by the system. The return air control strategy strives to keep the entire room at a fixed temperature. Therefore in a typical data center the CRAC supply temperature, and hence the air entering the racks, is 13-15°C and the CRAC return is 20-22°C. At these settings the CRACs can consume almost as much energy as the computer equipment they are cooling [Friedrich, R., Patel, C.D., 2002, “Towards Planetary Scale Computing – Technical Challenges for Next Generation Internet Computing,” THERMES 2002, Santa Fe, NM; The Uptime Institute, “Heat Density Trends in Data Processing, Computer Systems and Telecommunications Equipment,” White Paper issued by The Uptime Institute, 2000.]. Experiments conducted by the authors using these CRAC settings show that nearly 0.7W is consumed by the environmental control system for every 1W of heat dissipated by the computer equipment in the authors’ experimental facility indicating that the energy efficiency of standard data center environmental control systems is poor. This study examines several opportunities for improving thermal management and energy performance of data centers with automatic control. Experimental results are presented that demonstrate how simple, modular control strategies can be implemented. Furthermore, experimental data is presented that show it is possible to improve the energy performance of a data center by up to 70% over current standards while maintaining proper thermal management conditions.
Exact Solutions for the Functionally Graded Plates Integrated With a Layer of Piezoelectric Fiber-Reinforced Composite
Authors: Ray M. C. , Sachade H. M.
Published: June 2006

This paper deals with the derivation of exact solutions for the static analysis of functionally graded (FG) plates integrated with a layer of piezoelectric fiber reinforced composite (PFRC) material. The layer of the PFRC material acts as the distributed actuator of the FG plates. The Young’s modulus of the FG plate is assumed to vary exponentially along the thickness of the plate while the Poisson’s ratio is assumed to be constant over the domain of the plate. The numerical values of the exact solutions are presented for both thick and thin smart FG plates and indicate that the activated PFRC layer potentially counteracts the deformations of the FG plates due to mechanical load. The through-thickness behavior of the plates revealed that the coupling of bending and extension takes place in the FG plates even if the PFRC layer is not subjected to the applied voltage. The solutions also revealed that the activated PFRC layer is more effective in controlling the deformations of the FG plates when the layer is attached to the surface of the FG plate with minimum stiffness than when it is attached to the surface of the same with maximum stiffness. The solutions of this benchmark problem may be useful for verifying the other approximate and numerical models of the smart functionally graded plates for which exact solutions cannot be derived.
Transient Growth and Stick-Slip in Sliding Friction
Authors: Hoffmann Norbert
Published: June 2006

In linearly stable dynamical systems the non-normality of the corresponding linear operator is known to lead to transient growth of characteristic quantities, like, e.g., energy. For sliding friction systems it is shown in the present paper that this transient growth also applies to the sliding velocity and that under certain conditions this mechanism can lead to stick-slip limit-cycles in linearly stable system configurations.
Extending Koiter’s Simplified Equations to Shells of Arbitrary Closed Cross Section
Authors: Simmonds James G.
Published: June 2006

The techniques used by Koiter in 1968 to derive a simplified set of linear equilibrium equations for an elastically isotropic circular cylindrical shell in terms of displacements and the associated pointwise error estimate engendered in Love’s uncoupled strain-energy density are here extended to derive analogous simplified equilibrium equations and an error estimate for elastically isotropic cylindrical shells of arbitrary closed cross section.
Null-Field Integral
Equation Approach for Plate Problems With Circular
Boundaries
Authors: Chen Jeng-Tzong , Hsiao Chia-Chun , Leu Shyue-Yuh
Published: June 2006

In this paper, a semi-analytical approach for circular plate problems with multiple circular holes is presented. Null-field integral equation is employed to solve the plate problems while the kernel functions in the null-field integral equation are expanded to degenerate kernels based on the separation of field and source points in the fundamental solution. The unknown boundary densities of the circular plates are expressed in terms of Fourier series. It is noted that all the improper integrals are transformed to series sum and are easily calculated when the degenerate kernels and Fourier series are used. By matching the boundary conditions at the collocation points, a linear algebraic system is obtained. After determining the unknown Fourier coefficients, the displacement, slope, normal moment, and effective shear force of the plate can be obtained by using the boundary integral equations. Finally, two numerical examples are proposed to demonstrate the validity of the present method and the results are compared with the available exact solution, the finite element solution using ABAQUS software and the data of Bird and Steele.
Investigation of Flow and Heat Transfer of an Impinging Jet in a Cross-Flow For Cooling of a Heated Cube
Authors: Rundström D. , Moshfegh B.
Published: June 2006

The current trends toward the greater functionality of electronic devices are resulting in a steady increase in the amount of heat dissipated from electronic components. Forced channel flow is frequently used to remove heat at the walls of the channel where a PCB with a few high heat dissipating components is located. The overall cooling strategy thus must not only match the overall power dissipation load, but also address the requirements of the “hot” components. In order to cool the thermal load with forced channel flow, excessive flow rates will be required. The objective of this study is to investigate if targeted cooling systems, i.e., an impinging jet in combination with a low velocity channel flow, can improve the thermal performance of the system. The steady-state three-dimensional (3-D) model is developed with the Reynolds-Stress-Model (RSM) as a turbulence model. The geometrical case is a channel with a heated cube in the middle of the base plate and two inlets, one horizontal channel flow, and one vertical impinging jet. The numerical model is validated against experimental data obtained from three well-known cases, two cases with an impinging jet on a flat heated plate, and one case with a heated cube in a single channel flow. The effects of the jet Re and jet to-cross-flow velocity ratio are investigated. The airflow pattern around the cube and the surface temperature of the cube as well as the mean values and local distributions of the heat transfer coefficient are presented.
Massive-Star Supernovae as Major Dust Factories
Authors: Sugerman Ben E. K. , Ercolano Barbara , Barlow M. J. , Tielens A. G. G. M. , Clayton Geoffrey C. , Zijlstra Albert A. , Meixner Margaret , Speck Angela , Gledhill Tim M. , Panagia Nino , Cohen Martin , Gordon Karl D. , Meyer Martin , Fabbri Joanna , Bowey Janet. E. , Welch Douglas L. , Regan Michael W. , Kennicutt Robert C.
Published: June 2006

We present late-time optical and mid-infrared observations of the Type II supernova 2003gd in the galaxy NGC 628. Mid-infrared excesses consistent with cooling dust in the ejecta are observed 499 to 678 days after outburst and are accompanied by increasing optical extinction and growing asymmetries in the emission-line profiles. Radiative-transfer models show that up to 0.02 solar masses of dust has formed within the ejecta, beginning as early as 250 days after outburst. These observations show that dust formation in supernova ejecta can be efficient and that massive-star supernovae could have been major dust producers throughout the history of the universe.
Triploidy and mosaicism in Liolaemus chiliensis (Sauria: Tropiduridae)
Authors: Lamborot Madeleine , Manzur M E , Alvarez-Sarret E
Published: June 2006

A remarkable diversity of ploidy, i.e., diploidy, triploidy, and diploid–triploid mosaicism, was found among the somatic and testicular cells in a natural population of the lizard Liolaemus chiliensis from central Chile. Intra pop ulation, intersexual, and intraindividual ploidy variation is reported. In contrast with other species of polyploid reptiles, 86% of L. chiliensis males were mosaics (2n/3n) and 14% were diploids; 33% of females were triploid, 57.1% were mosaics, and 9.5% were diploid. Among 21 specimens, no triploid males were found in this sample. In the mosaic males, the diploid and triploid spermatogonia both enter meiosis, producing both reduced and unreduced metaphase II spermatocytes, most of them euploids. We discuss the origin for this ploidy in this iguanid lizard.Key words: Liolaemus chiliensis, triploidy, mosaicism for triploidy and diploidy, Sauria, Tropiduridae.
Analysis of QTLs for yield components, agronomic traits, and disease resistance in an advanced backcross population of spring barley
Authors: Li J Z , Huang X Q , Heinrichs F , Ganal M W , Röder M S
Published: June 2006

Hordeum vulgare subsp. spontaneum, the wild progenitor of barley, is a potential source of useful genetic variation for barley breeding programs. The objective of this study was to map quantitative trait loci (QTLs) in an advanced backcross population of barley. A total of 207 BC3lines were developed using the 2-rowed German spring cultivar Hordeum vulgare subsp. vulgare 'Brenda' as a recurrent parent and the H. vulgare subsp. spontaneum accession HS584 as a donor parent. The lines were genotyped by 108 simple-sequence repeat (SSR) markers and evaluated in field tests for the measurement of grain yield and its components, such as ear length, spikelet number per spike, grain number per spike, spike number, and 1000-grain mass, as well as heading date and plant height. A total of 100 QTLs were detected. Ten QTLs with increasing effects were found for ear length, spikelet number, and grain number per spike. Three QTLs contributed by HS584 were found to significantly decrease days to heading across all years at 2 locations. In addition, 2 QTLs from HS584 on chromosomes 2H and 3H were associated with resistance to leaf rust. Based on genotypic data obtained from this population, 55 introgression lines carrying 1 or 2 donor segments were selected to develop a set of doubled-haploid lines, which will be used to reconfirm and investigate the effects of 100 QTLs for future genetic studies.Key words: advanced backcross QTL analysis (AB-QTL), barley, simple sequence repeat, Hordeum vulgare subsp. spontaneum, introgression line.
Integrase diversity and transcription of the maize retrotransposonGrande
Authors: Gómez Eva , Schulman Alan H , Martínez-Izquierdo José Antonio , Vicient Carlos M
Published: June 2006

Grande is an abundant gypsy-like retrotransposon present in the genera Zea and Tripsacum. Related retro transposon families can be found in sorghum, rice, and barley, but not in wheat or rye. We have amplified and sequenced several copies of part of the integrase domain derived from the Zea mays, Zea diploperennis, and Tripsacum dactyloides genomes. There are no significant differences in divergence or clustering between the integrase sequences of these species. The substitution rate for synonimous sites was found to be higher than those of non-synomymous sites; this indicates that Grande integrase has been under purifying selection for function. Grande is transcribed in leaves. The transcripts show sequence diversity similar to that of genomic sequences, but belong to restricted clades; this indicates that only some evolutionary branches of Grande have retained transcriptional competence.Key words: maize, plant genome, retrotransposon, Zea diploperennis, Zea genus.
The clustering of four subfamilies of satellite DNA at individual chromosome ends inSilene latifolia
Authors: Kazama Yusuke , Sugiyama Ryuji , Suto Yumiko , Uchida Wakana , Kawano Shigeyuki
Published: June 2006

The satellite DNA (satDNA) on the ends of chromosomes has been isolated and characterized in the dioecious plant Silene latifolia. BAC clones containing large numbers of repeat units of satDNA in a tandem array were isolated to examine the clustering of the repeat units. satDNA repeat units were purified from each isolated BAC clone and sequenced. To investigate pairwise similarities among the repeat units, a phylogenetic tree was constructed using the neighbor-joining algorithm. The repeat units derived from 7 BAC clones were grouped into SacI, KpnI, #11F02, and #16E07 subfamilies. The SacI and KpnI subfamilies have been reported previously. Multicolored fluorescence in situ hybridization (FISH) using SacI or KpnI subfamily probes resulted in different signal intensities and locations at the chromosomal ends, indicating that each chromosomal end has a unique composition of subfamilies of satDNA. For example, the p arm of the X chromosome exhibited signal composition similar to that on the pseudo autosomal region (PAR) of the Y chromosome, but not to that on the q arm of the X chromosome. The satDNA has not been completely homogenized in the S. latifolia genome. Each subfamily is available for a probe of FISH karyotyping.Key words: BAC library, concerted evolution, multicolored FISH, karyotyping, satellite DNA, Silene latifolia.
Genetic diversity, reproductive biology, and speciation in the entomopathogenic fungusBeauveria bassiana(Balsamo) Vuillemin
Authors: Devi K Uma , Reineke A , Reddy N Nageswara Rao , Rao C Uma Maheswara , Padmavathi J
Published: June 2006

Beauveria bassiana, a mitosporic fungus used for the biological control of many insect species, is recognized as a "species complex" comprising genetically diverse lineages. Being predominantly asexual, mating tests cannot be applied to delimit species in this species complex. Genetic tests offer an indirect means of identifying species among isolates. To this end, molecular genetic analysis of a sample of B. bassiana isolates with 2 subsamples, 1 representing a worldwide collection and another from a localized epizootic population was carried out. DNA markers generated through AFLPs (amplified fragment length polymorphisms) and SSCPs (single-strand conformation poly morphisms) and nucleotide sequence data of different allelic forms of 3 genes (large and small subunits of rRNA and β-tubulin) were evaluated. The B. bassiana isolates from the worldwide sample showed 11% overall similarity and no closely clustered groups. Phylogenetic trees generated from the AFLP and SSCP data of this sample resolved the different isolates into distinct phylogenetic lineages. In the epizootic B. bassiana population, prevalence of recombination was evident from random association of alleles in multilocus tests and lack of phylogenetic concordance among 3 gene genealogies. Thus, the worldwide sample of B. bassiana exhibits a predominantly clonal structure, hinting at species divergence leading to cryptic speciation with recombination being customary among isolates sharing a close ecological niche.Key words: AFLP, asexual entomopathogenic fungus, Beauveria bassiana, clonal lineage/clonality, cryptic speciation, epizootic population, maximum parsimony analysis, multilocus analysis, multiple gene genealogies, recombination, SSCP, worldwide sample.
Behaviour of gusset plate connections to ends of round and elliptical hollow structural section members
Authors: Willibald S , Packer J A , Martinez-Saucedo G
Published: June 2006

Gusset plate connections to the ends of hollow structural section (HSS) members are regularly used in steel-framed buildings and roof trusses. Recent research on this connection type has indicated that current design recommendations for preventing tensile failure induced by shear lag may be overly conservative. This paper presents an experimental study on 13 gusset plate end connections to circular and elliptical HSS members under quasi-static tension and compression loadings. Current design proposals found in research studies and in design guides and specifications are compared with the experimental work. Various fabrication details for this connection type have been considered, and the influence of connection length, gusset plate orientation (in the tube long side versus short side), and distance between welds has been studied. In the experimental study, failure of all specimens under tensile loading was caused by circumferential fracture of the HSS or by tear-out of the HSS base material along the weld. The compression specimens failed by local buckling of the HSS at the connection end. A preferred static design approach for such connections is thus recommended.Key words: gusset plate, hollow section, tube, connection, round, elliptical, shear lag, tear-out failure.
Simple beam connections in combined shear and tension
Authors: Guravich Susan J , Dawe John L
Published: June 2006

An investigation into the behaviour of simple beam-to-column connections subjected to combined shear and tension was carried out by testing 108 full-scale specimens, including header angle, knife angle, single angle, and shear tab configurations. Specimens were rotated 0.03 rad, and a prescribed shear between zero and the design shear resistance was held constant while the specimens were loaded in tension to failure. Results showed significant differences in serviceability, ductility, interactions, and ultimate tension strength. Ductility was provided through yielding in bearing at bolt holes, bending of angle legs, and shear yielding of the gross section of connection elements. Tension and shear load versus displacement plots were acquired for all tests because of ductility and serviceability considerations in design. Existing methods of determining connection resistance, including bolt shear, net section shear, and bearing resistance, were used to compare predicted capacity with test results. The findings of the test program indicate that most simple connections can sustain significant amounts of tension in combination with design shear capacity.Key words: beam, connections, shear, tension, experimental, design, steel.
Prying action in bolted steel circular flange connections
Authors: Kumalasari Cindy , Ding Yongcong , Madugula Murty K.S
Published: June 2006

Both the Canadian Institute of Steel Construction (CISC) Handbook of Steel Construction and the American Institute of Steel Construction (AISC) Manual of Steel Construction discuss prying action in tee-type and angle-type connections subjected to tensile force, but no guidance is provided for determining the prying force in bolted steel circular flange connections. However, such connections are very common in leg members of guyed lattice communication towers. To determine the magnitude of the prying forces in such connections, an experimental investigation was conducted on 10 bolted steel circular flange connections. On the basis of the test data, it is proposed that for use with equations in the CISC handbook and AISC manual, the length of the flange tributary to each bolt (bolt pitch) be taken as the circumference of the bolt circle divided by the number of bolts.Key words: bolt pitch, bolted connections, circular flange, prying action, tensile force.
Nonorthogonal solution for thin-walled members – a finite element formulation
Authors: Erkmen R Emre , Mohareb Magdi
Published: June 2006

Conventional solutions for the equations of equilibrium based on the well-known Vlasov thin-walled beam theory uncouple the equations by adopting orthogonal coordinate systems. Although this technique considerably simplifies the resulting field equations, it introduces several modelling complications and limitations. As a result, in the analysis of problems where eccentric supports or abrupt cross-sectional changes exist (in elements with rectangular holes, coped flanges, or longitudinal stiffened members, etc.), the Vlasov theory has been avoided in favour of a shell finite element that offer modelling flexibility at higher computational cost. In this paper, a general solution of the Vlasov thin-walled beam theory based on a nonorthogonal coordinate system is developed. The field equations are then exactly solved and the resulting displacement field expressions are used to formulate a finite element. Two additional finite elements are subsequently derived to cover the special cases where (a) the St.Venant torsional stiffness is negligible and (b) the warping torsional stiffness is negligible. Key words: open sections, warping effect, finite element,thin-walled beams, asymmetric sections.
The implications of reuse and recycling for the design of steel buildings
Authors: Gorgolewski Mark
Published: June 2006

There is an increasing interest in reuse and recycling in the Canadian construction industry. This interest is driven partly by the recent adoption in Canada of the Leadership in Energy and Environmental Design (LEED®) Green Building Rating System and partly by a greater general awareness of environmental issues. Designers are beginning to look at how to incorporate reused steel components into construction projects, thereby reducing greenhouse gas emissions by saving on primary steel production. However, although some designers are willing to redesign their projects to make use of available reclaimed structural steel components, it is often difficult to identify suitable materials in the local area at the appropriate time in the life of a project. A limiting factor is that designers, construction companies, and others perceive a lack of a well-established and easily available mechanism for exchange of reclaimed components. This paper reviews the issues that are relevant to increasing recycling and reuse in construction and focuses on examples that illustrate the benefits that steel can bring to sustainable construction. In particular, it discusses the issues relevant to designing to enable future disassembly and the way in which steel components can be readily reused.Key words: reclaimed steel, reuse of materials, steel recycling, design for deconstruction, sustainable construction.
Analytical approach for shear lag in welded tension members
Authors: Abi-Saad Georges , Bauer Dominique
Published: June 2006

The authors propose an analytical approach for calculating the reduction in strength of steel tension members due to shear lag effects. The approach is based on an assumed distribution of forces along inclined lines in the member ends, somewhat similar to the Whitmore concept used with gusset plates for bracing members. The method is demonstrated for a basic weld in shear at elastic, plastic, and ultimate stress levels. The method is then compared with the recommendations contained in standard CAN/CSA-S16-01 for elements connected by a single longitudinal weld and for elements connected by longitudinal welds along two parallel edges. The predicted strength of tension members with welded connections is compared with results from several laboratory tests. The proposed method could be used for calculating the reduction in strength due to shear lag effects of tension members with different sections.Key words: steel structures, trusses, tension members, welded connections, shear lag, Whitmore.
Emerging processes in biosolids treatment, 2005
Authors: Kelly Harlan G
Published: June 2006

Achieving Class A treatment over Class B is becoming increasingly desirable. Most emerging new and improved processes are being promoted to meet Class A treatment objectives. Knowledge of these processes is also desirable to allow improved understanding of their current status and suitability. This paper reviews both digestion and reduction technologies and provides examples, advantages, and disadvantages for each. Key words: Class A biosolids treatment; emerging technologies; digestion: hydrolysis, thermophilic, pre-pasteurization; reduction: gasification, fuel from sludge, wet air oxidation, super critical water oxidation, hydrothermal.
Dynamic analysis of a biofilter treating autothermal thermophilic aerobic digestion offgas
Authors: Shanchayan B , Parker W , Pride C
Published: June 2006

There is little information to describe how a biofilter responds biologically and chemically to the dynamic loading of complex mixtures of contaminants that are present in autothermal thermophilic aerobic digestion (ATAD) offgases. This paper presents the results of a full-scale study that is the first stage in a longer project to evaluate the use of biofilters for treatment of ATAD offgases. In this study the composition and flow of offgases from an ATAD system located in McMinnville Oregon were characterized. The loading of reduced sulfur compounds (RSC) and ammonia (NH3) to a full-scale biofilter and the concentrations of these compounds in the treated air were measured on an hourly basis for a 24-h period, which was the feeding frequency for the ATAD system. The leachate from the biofilter was characterized for ammonium (NH4+), sulfate (SO42–), nitrate (NO3–), and nitrite (NO2–) concentrations to allow for mass balances on sulfur and nitrogen and to identify the biodegradation processes that were active in the biofilter. The removal efficiencies in the biofilter were more than 99% for hydrogen sulfide and methyl mercaptan and more than 94% for dimethyl sulfide and dimethyl disulfide. The total elimination rates of RSC and NH3 were 12.4 g-S m–3 d–1 and 6.5 g-N m–3 d–1, respectively. Almost 88% of the total mass of N in the leachate left from the biofilter as NH4+-N, while the remaining 12% was in the form of NO3-N and NO2-N. Key words: biofilter, ATAD, dynamic loading, hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, ammonia.
Detection of multiple paternity and sperm storage in a captive colony of the central Asian tortoise, Testudo horsfieldii
Authors: Johnston Emily E. , Rand Matthew S. , Zweifel Stephan G.
Published: June 2006

Reproductive success is a critical measure of an organism’s fitness. Determining reproductive success in vertebrates is confounded by the concealed mechanism and timing of fertilization (e.g., sperm competition and storage). To assess the relationship between observed mating behavior and reproductive success in the central Asian tortoise, Testudo horsfieldii Gray, 1844, we determined individual genotypes from a captive colony of adults and their offspring. We constructed a size-selected genomic library from T. horsfieldii and screened for polymorphic microsatellite markers. The screen resulted in identification of two novel microsatellite regions. Cross-species amplification of microsatellite markers using primers developed for the bog turtle, Glyptemys muhlenbergii (Schoepff, 1801), resulted in isolation of three additional polymorphic microsatellites for T. horsfieldii. The five loci, which have between 5 and 17 alleles and observed heterozygosities between 0.44 and 0.90, were used to determine the frequency of multiple paternity in the captive colony. We found evidence for multiple paternity in 27% of the clutches examined, as well as evidence for overwinter sperm storage and variance in adult male reproductive success. These data indicate that ample opportunity exists for sperm competition and female mate choice in T. horsfieldii.
Effects of synchronization with host plant phenology occur early in the larval development of a spring folivore
Authors: Jones B.C. , Despland E.
Published: June 2006

Early spring feeding Lepidoptera depend on synchronization of larval emergence with host plant phenology for optimal growth and development. Physical and chemical characteristics of foliage change over the course of the growing season, and a delay in larval emergence therefore results in larvae foraging on lower quality food. We examine the effect of synchronization of larval emergence with leaf phenology on the entire larval stage of the forest tent caterpillar, Malacosoma disstria Hübner, 1820 (Lepidoptera: Lasiocampidae). Caterpillars were reared from egg hatch to pupation on trembling aspen, Populus tremuloides Michx; 10 days separated egg hatch in the early and late treatments. Late-hatching caterpillars experienced reduced growth in the early instars, but growth in the later instars did not differ between treatments. Reduced growth early in development resulted in both prolongation of the larval stage through the occurrence of additional instars, and lower pupal mass. Aspen foliage quality changes rapidly during leaf expansion, and the late-hatching caterpillars likely missed the narrow window of opportunity for young larvae to feed on high-quality developing foliage. This study demonstrates the importance of early-instar ecology in Lepidoptera.
Factors influencing variation in site fidelity of woodland caribou (Rangifer tarandus caribou) in southeastern British Columbia
Authors: Wittmer Heiko U. , McLellan Bruce N. , Hovey Frederick W.
Published: June 2006

Where predation is a major limiting factor, it has been postulated that woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)) reduce movements to minimize contact with predators and exhibit fidelity to seasonal ranges. We examined fidelity behaviour within season and among years of woodland caribou based on locations of 65 radio-collared individuals in British Columbia, Canada. We used average linear distances between all possible pairs of radiolocations of individuals to assess fidelity. Among-year interlocation distances were similar to within-season interlocation distances during summer, indicating that caribou did not shift their distribution during seasons when they were most vulnerable to predation. Among-year interlocation distances were significantly greater than within-season interlocation distances during both early winter and late winter, indicating that individual caribou shifted their distribution among winters. The amount that an individual’s distribution shifted among winters varied among and within individuals over different years. During early winter this behavioural plasticity was correlated with snow accumulation, with individuals having greater interlocation distances in years with high snow accumulation. Our results indicate that site fidelity outside the calving season is unlikely solely influenced by predator avoidance. We suggest that seasonal shifts in the importance of limiting factors vary from predation in summer to food in winter.
Brinckmannia hexactinellidophila, n. gen., n. sp.: a hydroid living in tissues of glass sponges of the reefs, fjords, and seamounts of Pacific Canada and Alaska
Authors: Schuchert Peter , Reiswig Henry M.
Published: June 2006

This paper reports on an intimate association of a cnidarian with glass sponges. Hexactinellid sponges of the genus Heterochone were found to regularly contain numerous tiny hydroids in their tissue. The hydroid belongs to a new genus and species and is here named Brinckmannia hexactinellidophila. Brinckmannia hexactinellidophila is a reduced form, lacking tentacles and gonophores, which certainly is an adaptation to its endobiotic mode of life. The possession of desmonemes allows it to be classified as a member of the suborder Filifera of the order Anthoathecata. The shape of the hydranth reveals some clear affinities with the Proboscidactylidae, a relationship which is also strongly suggested by a comparison of 16S gene sequences. Because a closer relationship to some other families cannot be excluded at this stage, the new genus is nevertheless not assigned to any known family and classified as Filifera incertae sedis.