bluuebunny/crossref_metadata_2025 huggingface dataset:
Obesity and Dental Caries in Children Aged 2‐6 Years in the United States: National Health and Nutrition Examination Survey 1999‐2002
Authors: Hong Liang , Ahmed Arif , McCunniff Michael , Overman Pam , Mathew Moncy
Published: March 2008

Objective: This study assessed the associations between obesity and dental caries in young children participating in a national survey. Methods: Participants included 1,507 children aged 2‐6 years who received dental examinations and had at least 10 primary teeth in the National Health and Nutrition Examination Survey 1999‐2002. Decayed/filled teeth (dft) counts of primary dentition were obtained, and weight and height were measured. Body mass index (BMI; kg/m
2
) was calculated, and participants were categorized using age‐ and gender‐specific criteria as underweight (<5th percent), normal (5th‐85th percent), at risk for overweight (>85th and <95th percent), and overweight (≥95th percent). With appropriate sample weighting, relationships between dft and BMI were assessed using the Kruskal–Wallis test and multivariable logistic regression. Results: Seventy‐four percent of children were classified as normal weight, 11 percent as at risk for overweight, and 11 percent as overweight; 58 percent did not have caries; 30 percent had 1‐5 dft and 12 percent had >5 dft. When caries experience was compared across BMI categories stratified by age and race characteristics, statistically significant association between caries and obesity was found only for 60‐ <72‐month age group. In the comparison between children with normal and at‐risk BMI only, significant associations were also found in the Hispanic and non‐Hispanic Black strata. In multivariable logistic regression models to predict caries experience, family income and age were statistically significant predictors for severe early childhood caries only. Conclusions: There appears to be no significant association between childhood obesity and caries experience after controlling for age, race, and poverty/income ratio. However, further studies are needed to better understand this relationship.
Angiotensin‐converting enzyme 2 gene targeting studies in mice: mixed messages
Authors: Gurley Susan B. , Coffman Thomas M.
Published: March 2008

As a major regulator of blood pressure homeostasis, the renin–angiotensin system (RAS) has been the subject of extensive scientific investigation. While the RAS was first discovered more than 100 years ago, several novel components of the system have been identified only in the last decade. One of these newer members of the RAS family is angiotensin‐converting enzyme 2 (ACE2). Among the approaches used to establish a physiological role for ACE2 has been the generation of ACE2‐null mouse lines using homologous recombination in embryonic stem cells. In the literature, there have been at least three lines of ACE2 knockout mice generated by gene targeting by different investigative groups. Interestingly, there are significant differences in some of the reported phenotypes of these distinct lines, especially with regard to their cardiovascular physiology. In this paper, we will review the results of published experiments using these ACE2‐null mouse lines, highlighting similarities and differences in these studies and summarizing their contributions to our understanding of the physiological functions of this novel member of the RAS.
Teleoperation Hybrid Robot for Cell Micro and Nano Manipulations
Authors: Ionescu Florin , Talpasanu Ilie
Published: March 2008

In this paper is presented a developed robotic system for cell micro/nano manipulation and penetration, based on the visual/haptic interface. The operator’s motion and manipulations skills are transferred to the robot control system by direct teleoperation. The robot’s regional structure has three translational joints and one passive rotational joint for the nanorobot adjustment. The three-d.o.f piezo actuated nano robot is a compact and stiff structure, to guarantee the three-dimensional nano motion and control for sample manipulation or injection. The closed kinematic structure with two fundamental loops has been chosen for the required working space, high speed, and precision. The digraph-matroid approach is used for the model’s kinematics, and the SDS software for the robot’s simulation.
Biomechanical Evaluation of a Wide-Diameter Short Dental Implant for Use in Compromised Bone Quality Regions by Finite Element Method
Authors: Chou Hsuan-Yu , Mu¨ftu¨ Sinan , Bozkaya Dinc¸er
Published: March 2008

The success rates of dental implant treatments in posterior mandible and maxilla could be compromised due to the increased masticatory forces and poor bone quality. In addition, the length of the implant is limited by maxillary sinus and mandibular canal in these regions. Wide-diameter short (WDS) implants provide a good alternative to increase the stability and the reliability of the implants in such conditions. The objective of this study is to evaluate the biomechanical properties of a wide implant by performing finite element analyses (FEA). Comparison of the strain distribution induced in the bone by a WDS implant and by a narrow-diameter long (NDL) implant, in clinical scenarios exhibiting different amounts of crestal bone, and under varying insertion depths demonstrated that WDS implant can be used safely and should perform as well as its NDL counterpart.
A New Paradigm for Neurological Lead Cyclic Testing
Authors: Wisnewski Paul
Published: March 2008

The feasibility of electrical stimulation of the nervous system to treat chronic pain was proven with implantation of the first device for this purpose by Norm Shealy, MD in 1967. Since then, neurological stimulation has become a standard therapy for pain management.
Percussion Probe Analysis of Implant Stability and Structural Defects in Biological Tissues
Authors: Earthman James C. , VanSchoiack Lindsey R. , Sheets Cherilyn G.
Published: March 2008

Dynamic loading response has been a subject of concern in a number of studies in the field of restorative medicine. For example, implant borne prostheses are generally made of materials that primarily undergo elastic deformation under dynamic loading, storing and transmitting almost as much mechanical energy as is input to the system. By contrast, cartilage and ligament tissues act as shock absorbers, deforming anelastically in a manner that dissipates a significant amount of the available mechanical energy. This difference between implant structures and their natural counterparts can be problematic and result in unforeseen failure of implants and the surrounding tissues. However, the sources of many of these problems can be avoided altogether or at least corrected if they are carefully tested and monitored with advanced diagnostics.
Simulation of Renal Stent in Respiration
Authors: Hsiao Hao-Ming , Nikanorov Alexander , Prabhu Santosh , Razavi Mahmood K.
Published: March 2008

Atherosclerotic renal artery stenosis is a common manifestation of generalized atherosclerosis and is the most common disorder of the renal arterial circulation. Despite the proven efficacy of surgical revascularization, endovascular therapy has emerged as the preferred strategy for treatment. Balloon-expandable stents for aorta-ostial renal artery stenosis is demonstrated to be a safe and effective therapy [1].
Cyclic Property of Nitinol and Its Impact on Finite Element Analysis
Authors: Gong Xiao-Yan , Rebelo Nuno , Morgan N. , Pelton Alan R.
Published: March 2008

The increasing number of therapeutic options employing Nitinol devices and an associated more thorough understanding of the often complex in-vivo loading conditions such as that experienced in the SFA (superficial femoral artery) is demanding a better understanding of Nitinol fatigue behavior. Allied to this increase of applications is a demand for improved predictive modeling using Finite Element Analysis (FEA).
Continuous-Flow Microfluidic Devices for Detection of Bacterial Endospores
Authors: Wan Jiandi , Landsman Pavel , Xia Bing , Bower Paul E. , Heinrich Volkmar , Jones Guilford , Vullev Valentine I.
Published: March 2008

Using non-lithographic fabrication methods developed in our laboratory, we prepared continuous-flow microfluidic analyzers. We tested these devices in experiments involving detection of bacterial endospores. The detection was based on the enhancement of the fluorescence of a cationic dye, 3,3′-diethylthiacyanine iodide (THIA), in the presence of spores. We were able to detect as few as ~105 spores when injected in a device. The measurements with the micro-fluidic devices manifested significantly higher sensitivity for bacterial spores than for vegetative bacteria. Such distinction between spores and vegetative bacteria could not be achieved with THIA using steady-state emission measurements.
Effect of Surface Treatment on Surface Characteristics and Biocompatibility of AISI 316L Stainless Steel
Authors: Selvaduray Guna , Trigwell Steve
Published: March 2008

Surface characteristics are essential in determining the biocompatibility of medical implants. Surface treatments such as mechanical polishing, electropolishing, passivation and plastic strain of AISI 316L stainless steel was found to affect the critical surface tension, with the combined electropolishing and passivation treatment resulting in the most desirable critical surface tension for biocompatibility. AES and XPS analysis showed that electropolishing results in changing the surface chemical composition significantly. There is significant Cr enrichment on the surface, compared to the bulk. The surface Cr and Fe exist as a combination of oxides and hydroxides.
Hollow-Fiber Cartridges: Model Systems for Virus Removal From Blood
Authors: Menon Jeevan G. , Duffin R. Paul , Tullis Richard H. , Jacobitz Frank G.
Published: March 2008

Aethlon Medical is developing an extracorporeal blood filter as a therapeutic device designed to remove viruses and toxins from the blood of patients. The Hemopurifier is a modified hollow-fiber plasmapheresis cartridge containing an affinity matrix in the extra capillary space. The matrix contains a high mannose specific lectin as the active capture agent. The flow configuration of the device is that of Starling flow. The filter is designed to clear viruses and toxins from blood, delaying illness so the patient’s immune system can fight off the virus. Results to date indicate the efficient removal of a variety of enveloped viruses including HIV, HCV and poxviruses with in vitro evidence indicating the ability to capture Dengue fever virus, measles, mumps, influenza, Ebola and Marburg. Possible additional targets include bioweapons such as smallpox and bacterial toxins. A schematic of the use of the filter in a therapeutic application is shown in figure 1. In order to optimize the design of such a filter, the fluid mechanics of the device is modeled analytically and investigated experimentally. Additional information can be found in Tullis et al. [1], Tullis et al. [2], and Duffin and Tullis [2].
Auxetic Drug-Eluting Stent Design
Authors: Dolla William Jacob S. , Fricke Brian A. , Becker Bryan R.
Published: March 2008

A cardiovascular stent is a cylindrical wire mesh structure that is permanently introduced into an artery during angioplasty (balloon dilatation) to act as a scaffold, thus preventing elastic recoil and/or sudden collapse of the damaged artery. While cardiovascular stents virtually eliminate elastic recoil and/or collapse of the artery, recognition of the stent as a foreign material triggers a human immune system response causing re-closure, or restenosis, of the artery. A recent advancement to counteract restenosis is to employ drug-eluting stents to locally deliver immunosuppressant and antiproliferative drugs.
The Pulling Device for a Flexible Bronchoscope
Authors: Ludeke D. Taylor , Mirmirani Maj Dedin
Published: March 2008

The flexible bronchoscope, used both to directly visualize and biopsy lesions, is an important tool for diagnosing lung cancer [1]. Presented here is a conceptual design for a device that increases the depth to which the scope can be fed into the lungs. This allows doctors to find and accurately diagnose more cases of lung cancer first occurring deeper in the lungs.
Evaluation of planting sites common to a southeast Alaska clear-cut. I. Nutrient status
Authors: Sidle Roy C. , Shaw III Charles G.
Published: March 2008

Nutrient status was evaluated in the upper 15 cm of three microsite types (rotten wood, exposed mineral soil, and undisturbed duff) common in old-growth western hemlock – Sitka spruce (Tsugaheterophylla (Raf.) Sarg.) – (Piceasitchensis (Bong.) Carr.) clear-cuts. Rotten wood had significantly wider C:N ratio (>100:1) than either undisturbed duff (36:1) or exposed mineral soil (31:1), indicating lower nitrogen availability in rotten wood. Higher levels of inorganic [Formula: see text] in <2 mm fraction of rotten wood compared with the 2- to 9.4-mm fraction indicate that N availability increases as decay advances. Available P was low and could be a major factor limiting growth in all microsites. Exchangeable Mg was relatively low (0.0025 mg/cm3) in exposed mineral soil. Microsite nutrient expression on a volumetric rather than a gravimetric basis better represents availability of nutrients to planted seedlings.
Leaf-litter production and soil organic matter dynamics along a nitrogen-availability gradient in Southern Wisconsin (U.S.A.)
Authors: Nadelhoffer Knute J. , Aber John D. , Melillo Jerry M.
Published: March 2008

Annual net N mineralization in the 0–10 cm mineral soil zone of nine forest stands on silt–loam soils was measured using a series of insitu soil incubations from April 1980 through April 1981. Differences in soil organic matter (SOM) dynamics among sites were shown with net N mineralization ranging from 0.54 to 2.10 mg N mineralized•g SOM−1•year−1. This variation was not related to percent N in SOM. Net N mineralization varied seasonally with maximum rates in June and very low rates in winter. Nitrification rates were constant from May through September despite fluctuations in soil ammonium pools. Nitrification was greater than 50% of annual net N mineralization at all sites. N uptake by vegetation, as estimated by net N mineralization plus mineral N inputs via precipitation, with minor corrections for mineralization below the incubation depth and for mineral N losses to groundwater, ranged from 40.3 to 119.2 kg N•ha−1•year−1. Annual leaf and needle litter production ranged from 2.12 to 4.17 Mg•ha−1•year−1 and was strongly correlated with N uptake (r = 0.938, P < 0.01). N returned in leaf litter was also correlated with N uptake (r = 0.755, P < 0.05). Important feedbacks may exist between N availability and litter quality and quantity.
Predicting soil moisture depletion beneath trembling aspen
Authors: Mital David , Sucoff Edward
Published: March 2008

Soil moisture and potential evapotranspiration were monitored in four stands of Populustremuloides Michx. during two growing seasons. Measured soil moisture was compared with soil moisture predicted by four models: THIRSTY, SOGGY, Zahner's, and a simple water budget. THIRSTY, an original model incorporating many soil layers, root density, and a variable resistance to moisture flux, generally gave the best fit. Water uptake was related to relative root density.
Host preferences of the gypsy moth, Lymantriadispar (L.), in southern Quebec
Authors: Mauffette Yves , Lechowicz Martin J. , Jobin Luc
Published: March 2008

Larval populations of gypsy moth were monitored from June through July 1980 in southwestern Quebec, the northern edge of the insect's North American range. Larval activity on a total of 1870 trees representing 29 tree species was studied at 13 different sites. At least some gypsy moth larvae were found on all tree species, but different larval preferences for the available host trees were evident. Gypsy moth larvae preferentially attacked Quercusrubra L., Amelanchier spp., Populusgrandidentata Michx., Salix sp., and Ostryavirginiana (Mill) K. Koch. The larvae generally avoided members of the genus Fraxinus, Acernegundo L., A. pensylvanicum L., A. rubrum L., A. saccharinum L., Betulalutea Michx. f., Caryacordiformis (Wang) K. Koch, C. ovata (Mill) K. Koch., Juglanscinerea L., Pinusstrobus L., Populusdeltoides Marsh., Prunuspensylvanica L.f., Pyrusmalus L., and Ulmusrubra Muhl. The following species are best categorized as intermediate hosts whose utilization varies with forest composition: Acersaccharum Marsh., Betulapapyrifera Marsh., B. populifolia Marsh., Fagusgrandifolia Ehrh., Populustremuloides Michx., Prunusserotina Ehrh., Tiliaamericana L., and Ulmusamericana L. Some differences were found from host preferences reported for New England. For example, Ostryavirginiana is strongly preferred in Quebec in contrast to New England where it is only an intermediate host; Betulapopulifolia and Populustremuloides are both preferred in New England but classed as intermediate hosts in our study. Overall, the forest composition appears to play only a limited role in altering gypsy moth host selection, but does especially affect the utilization of intermediate hosts.
Interference by weeds and deer with Allegheny hardwood reproduction
Authors: Horsley Stephen B. , Marquis David A.
Published: March 2008

Deer browsing and interference from forest weeds, particularly hayscented fern (Dennstaedtiapunctilobula (Michx.) Moore), New York fern (Thelypterisnoveboracensis L.), and short husk grass (Brachyelytrumerectum Schreb.), influence the establishment of Allegheny hardwood reproduction. We determined the independent interference by deer and weeds after a seed cut and a removal cut in a two-cut shelterwood sequence. Weeds, particularly the ferns, caused significant interference with germination, survival, and growth of desirable species following both cuttings. Deer browsing had no direct effect on desirable species because they did not grow enough to emerge from the herbaceous cover. Deer browsing did affect growth ofRubus, yellow and black birch (Betulaalleghaniensis Britt, and Betulalento L.), and pin cherry (Prunuspensylvanica L.) that grew above the herbaceous cover. Browsing of Rubus may be a serious problem in some stands because substantial reduction in fern and grass coverage occurred as the Rubus developed.
Growth basal area: a field method for appraising forest site potential for stockability
Authors: Hall Frederick C.
Published: March 2008

Growth basal area (GBA) is a field method for determining site potential limitations on stockability. It is defined as the basal area (BA) at which dominant trees grow 1 in. (25 mm) diameter per decade at age 100. Diameter growth is a constant used to compare sites; basal area is a variable used to express different site potentials for stockability. For example, a site with GBA = 220 ft2/acre (50 m2/ha) means dominants will grow 1 in. per decade (25 mm) in diameter at 220 ft2 BA. This is twice the stockability potential of a site with GBA = 110 ft2 (25 m2/ha). GBA is determined by relating current stand diameter growth rate and BA to a curve which permits adjustment of current BA to that for 1 in. per decade diameter growth. GBA is based on two assumptions: (i) rate of diameter growth decreases with increasing basal area and is an index of intertree competition. (ii) Change in GBA with age is related to stand age. GBA can be combined with site index (SI), shown as SI-GBA, to connote different productivities within an SI class. GBA is discussed in regard to concept of GBA curve development, assumptions made, applications, and constraints.
The hybrid black × Sitka spruce, implications to phylogeny of the genus Picea
Authors: Fowler D. P.
Published: March 2008

Between 1974 and 1981, the cross black spruce (Piceamariana (Mill.)B.S.P.) × Sitka spruce (P. sitchensis (Bong.) Carr.) was attempted on over 2000 black spruce strobilis on 39 trees. Of 58 different tree × pollen combinations attempted, 48 yielded viable seeds. Species crossability, although highly variable on an individual-tree basis, averages about 5%. Hybrid seeds have slightly poorer germination and produce more abnormal seedlings than nonhybrid seeds. The hybrid seedlings are intermediate between the parents for most taxonomic characters and are clearly distinguishable from the parents on the basis of bud scale shape and serrations. Within-family variation in growth is higher in hybrid than in nonhybrid families, and most hybrid families contain a few exceptional seedlings. Methods of mass producing these exceptional seedlings are discussed. It is suggested that black spruce and Sitka spruce should be placed in different subsections of section Omorika, genus Picea.
Les pinales, considérées d'un point de vue chimiotaxinomique
Authors: Lebreton Philippe , Sartre Janine
Published: March 2008

The analysis of flavonoids in 132 samples (92 species, 9 genera) of pinales (Emberger sensu) has allowed the authors to justify autonomy of this group and to specify its internal structure. The absence of biflavones, the presence of C-glycoflavones, and the high concentration of prodelphinidin distinguish the pinales from the other conifers. Although we cannot define families or subfamilies in this order, we can consider the three genera Abies, Pinus, and Picea as distinct phytochemical types. In some genera (Abies), the occurrence of flavonoids is correlated with biogeographical variation or with botanical sectionement; in other genera (Picea) there is no such relation. While some species (Abiespectinata (Lmk.) DC) are remarkably homogeneous, others (Piceaexcelsa Link., Pinussylvestris L., Pseudotsugamenziesii (Mirb.) Franco) show a definite polymorphism among flavonoids; these last results can serve as a basis for further infraspecific studies.
Initiation of adventitious root primordia in very young Pinusbanksiana seedling cuttings
Authors: Montain Cheryl R. , Haissig Bruce E. , Curtis John D.
Published: March 2008

The present work describes the anatomy of adventitious root initiation in 20-day-old Pinusbanksiana Lamb, seedling cuttings propagated under intermittent mist. Shortly after cuttings were made, basal necrosis occurred in all tissues (epidermis, periderm, cortex, primary and secondary phloem, and vascular cambium) that surrounded the central xylem cylinder. Thereafter, a relatively small "callus complex" composed of parenchyma cells, a few secondary xylem tracheids, and incompletely differentiated callus vascular cambium and periderm developed at the base of cuttings. One or sometimes two root primordia initiated in the transition zone between the lowermost cortical cells of the hypocotyl and the uppermost callus parenchyma cells. Primordia invariably arose just outside one of the four axial resin canals in the hypocotyl. Results suggested that adventitious root primordia may be initiated in P. banksiana cuttings only in association with differentiated or differentiating resin canals.
Differentiation of adventitious root primordia in callus of Pinusbanksiana seedling cuttings
Authors: Montain Cheryl R. , Haissig Bruce E. , Curtis John D.
Published: March 2008

The root systems of 97-day-old seedlings of Pinusbanksiana Lamb, were severed just below the lowermost needles, and the cuttings were placed in misted propagation benches. A complex of tissues including callus, vascular cambium, secondary xylem, periderm, and resin canals formed at the base of cuttings. Adventitious root primordia were initiated at the periphery of the basal-most portions of this complex in association with resin canals, tracheid "nests", periderm, and, possibly callus vascular cambium. Anatomical complexity of the developing tissues precluded more specific identification of sites of primordium initiation.
Effects of sex hormone levels on aortic vascular reactivity and variables associated with the metabolic syndrome in sucrose-fed female rats
Authors: Pérez-Torres Israel , El Hafidi Mohammed , Infante Oscar , Baños Guadalupe
Published: March 2008

We studied the effect of varying levels of sex hormones, induced by ovariectomy and administration of testosterone or estradiol, on aortic reactivity in female rats with metabolic syndrome (MS) induced by a sucrose diet. Vasoreactivity of aortic rings, blood pressure, intra-abdominal fat, serum triglycerides, nitrates and nitrites, and TBARS were evaluated. Intact MS and ovariectomized MS had higher BP than intact control (C) and ovariectomized C, respectively; estradiol administration decreased BP in ovariectomized MS but not in ovariectomized C. Triglycerides and fat were both higher in MS. Triglycerides were not modified by surgery or hormone treatment, but ovariectomy increased fat. When ovariectomy was combined with hormones, however, fat was reduced to the level of intact rats. Ovariectomy decreased, but hormones increased, serum nitrates and nitrites. Vasoconstriction was larger in intact MS and ovariectomized MS + testosterone aortas than in intact C and ovariectomized C + testosterone, respectively. Vasodilation was reduced in intact MS and ovariectomized MS + testosterone compared with intact C, ovariectomized C + testosterone, ovariectomized MS, and ovariectomized MS + estradiol. The results suggest endothelial dysfunction in intact MS and ovariectomized MS + testosterone, but protection by ovariectomy + estradiol in MS due to hormones. Indomethacin reduced all contractions, but the effect was greater in estradiol-treated rats. l-NAME increased contractility, more in the ovariectomized C and MS groups and less in the estradiol-treated groups.
Adenosine reduces the reverse mode of the Na+/Ca2+exchanger in ferret cardiac fibres
Authors: Hleihel W. , Lafoux A. , Ouaini N. , Huchet-Cadiou C.
Published: March 2008

The aim of this study was to investigate the effects of adenosine on reverse mode Na+/Ca2+exchange. In intact ferret cardiac trabeculae, Na+-free contractures were investigated after treating preparations with ryanodine, a sarcoplasmic reticulum Ca2+-channel inhibitor, and thapsigargin, a sarcoplasmic reticulum Ca2+-pump inhibitor added to suppress the sarcoplasmic reticulum function. The effects of adenosine (50–100 nmol/L), adenosine deaminase (ADA, 0.1–0.5 U/L), the A1and A2Areceptor agonists CCPA (3–100 nmol/L) and CGS 21680 (25–100 nmol/L), and the A1and A2Areceptor antagonists DPCPX (25 nmol/L) and ZM 241385 (25 nmol/L) were tested on Na+-free contractures. The application of adenosine (50–100 nmol/L) had no significant effect on the characteristics of the Na+-free contractures. However, the results show that treatment with ADA (0.3 U/L), adenosine (≥50 nmol/L) and CCPA, a specific A1receptor agonist (3–100 nmol/L), all reduced the Na+-free contracture amplitude. In the presence of ADA, the effects of adenosine and CCPA were also reduced by a specific antagonist of A1receptors (DPCPX, 25 nmol/L). Furthermore, adenosine, ADA, and CCPA did not affect the properties of the contractile apparatus in Triton-skinned fibres. It is therefore proposed that endogenous adenosine reduced the reverse mode of the Na+/Ca2+exchanger by acting on A1receptors present in the sarcolemmal membrane.
Role of endogenous nitric oxide synthase inhibitor in gastric mucosal injury
Authors: Wang Li , Zhou Yuan , Peng Jun , Zhang Zhe , Jiang De-Jian , Li Yuan-Jian
Published: March 2008

To explore the role of the endogenous nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) in gastric mucosal injury, 3 models of gastric mucosal injury induced by ethanol, indomethacin, or cold stress were used in rats. The cultured human gastric mucosal epithelial cell line GES-1 infected by Helicobacter pylori (Hp) was selected to mimic human gastric mucosal injury. Gastric mucosal ulcer index (UI), levels of ADMA and NO, and activity of dimethylarginine dimethylaminohydrolase (DDAH) were determined in the mucosal injury models; in Hp-infected or ADMA-treated GES-1 cells, levels of ADMA, NO, and TNF-α and activity of DDAH were measured. The results showed that UI and levels of ADMA were markedly increased and accompanied by significantly decreased DDAH activity in the mucosal injury models. Incubation of GES-1 cells with Hp increased levels of TNF-α and ADMA and decreased activity of DDAH. Administration of ADMA also increased levels of TNF-α. The results suggest that ADMA plays an important role in facilitating gastric mucosal injury, an effect which is associated with inhibiting NO synthesis and inducing inflammatory reaction.
Overexpression of Gsα compensates for myocyte loss in diabetic cardiomyopathyPresented in part at the American Heart Association meeting, New Orleans, Louisiana, November 2004.
Authors: Malhotra Ashwani , Kang Barinder P.S. , Vashistha Himanshu , Yadav Virender S. , Meggs Leonard G.
Published: March 2008

The stimulatory G protein Gsα transmits signals from activated β-adrenergic receptors via the cyclic AMP–PKA pathway, targeting the key regulatory protein phospholamban. We hypothesized that mice with intrinsic activation of cardiac Gsα are resistant to the development of the diabetic cardiomyopathy phenotype. Accordingly, streptozotocin (STZ)-diabetes mellitus was induced in genetically engineered mice with cardiac-specific Gsα overexpression and in nontransgenic (NTG) littermates. At 8 weeks, Gsα diabetic mice showed no impairment of LV contractility nor increase in myocyte apoptosis, whereas NTG diabetic mice showed a 30% decrease in +dP/dt and –dP/dt with sustained (3-fold) myocyte loss by apoptosis. To assess the level of myocardial reactive oxygen species, we measured malondialdehyde, a surrogate marker of oxidative stress, which was increased in the hearts of NTG and Gsα diabetic mice. In addition, chronic hyperglycemia also increased the activity of catalase and superoxide dismutase in the hearts of NTG and Gsα diabetic mice. Hearts of NTG diabetic mice, but not Gsα mice, showed increased expression of proapoptosis Bax, downregulation in Bcl2, and an increase in the Bax/Bcl2 ratio. Hearts of NTG diabetic mice showed 60% reduction in phosphorylation at the critical Ser16 residue of phospholamban, whereas phosphorylation at Ser16 was restored in hearts of Gsα-diabetic mice. We conclude that cardiac-specific overexpression of Gsα compensates for the loss of cardiac function in diabetes mellitus.
Stable carbon and nitrogen isotope values in teeth of Steller sea lions: age of weaning and the impact of the 1975–1976 regime shift in the North Pacific Ocean
Authors: York A. E. , Thomason J. R. , Sinclair E. H. , Hobson K. A.
Published: March 2008

We measured δ15N and δ13C values and tooth width from the first 4 years’ dentinal growth layer groups (GLGs) in the teeth of 113 female Steller sea lions ( Eumetopias jubatus (Schreber, 1776)) born between 1960 and 1983, a period that included a large population decrease and a climate regime shift. A linear discriminant analysis on the δ13C and δ15N values estimated 60% of Steller sea lions were weaned in their 1st year, 30% in their 2nd year, and 8% in their 3rd year. GLG-1 was wider in “weaned” animals than those still “nursing” in their 2nd year, suggesting that faster growing pups weaned earlier. Except during the regime shift, the average age at weaning increased and the size of GLG-1 in weaned animals decreased. We suggest that during the regime shift a greater proportion of pups which survived (to have their teeth sampled for this study) grew faster and were weaned by the end of their 1st year. We hypothesize that the long-term weaning age increase and growth rate decrease are consistent with a change in relative mortality of weaned pups and those that continued to nurse, possibly caused by a reduction in available resources, characterized as a switch from a “live-fast” to a “live-slow” life history.
Molecular phylogenetics of central Canadian Physidae (Pulmonata: Basommatophora)
Authors: Pip E. , Franck J.P.C.
Published: March 2008

The phylogenetic relationships of four nominal south-central Canadian freshwater physids ( Physa (sensu lato) skinneri Taylor, 1954, Physa integra (Haldeman, 1841), Physa gyrina (Say, 1821), and the endemic Physa winnipegensis Pip, 2004) were studied by analyses of combined partial sequences coding for mitochondrial 16S and cytochrome c oxidase (COI) genes. Maximum parsimony and neighbour joining analyses, as well as comparisons with published sequences, supported four major clades of physids, of which three are represented in central Canada. Physa skinneri and P. integra were placed within the Physa fontinalis (L., 1758) and Physa acuta Draparnaud, 1805 clades, respectively. Physa winnipegensis formed a distinct branch within the P. acuta group. An additional, previously unreported and unclassified, morph within the P. acuta group was identified from Lake Winnipeg.
Male sperm whale (Physeter macrocephalus) coda production and coda-type usage depend on the presence of conspecifics and the behavioural context
Authors: Frantzis Alexandros , Alexiadou Paraskevi
Published: March 2008

Sperm whale ( Physeter macrocephalus L., 1758 (=  Physeter catodon L., 1758)) codas serve a communication function, but the message they carry remains unknown. Very few codas and extremely few coda types are available from males. For 7 years we studied the coda occurrence and the coda types produced by 15 males in different behavioural and encounter contexts. Of the 67 encounters, 615 codas were produced by nonsolitary males. Codas occurred in 60% of the nonsolitary encounters and 36% of the dive cycles. Four hundred and ninety codas have been categorized into 8 coda families and 25 distinctive coda types. Both the coda type used and the dive cycle phase in which codas occurred strongly depended on the behavioural context. This is the first time that coda types have been associated with particular behavioural contexts. The “Three plus” family coda types were mainly used by ascending or descending whales in feeding dive cycles. The “Regular” and “Progressive” families were used almost exclusively by interacting whales. The “Root” coda family was used exclusively at surface, mainly in altered dive cycles. The coda types used in these three behavioural contexts seem to carry different messages and are proposed to be named “dive cycle codas”, “social codas”, and “alarm codas”, respectively.
Discrimination of carbon and nitrogen isotopes from milk to serum and vibrissae in Alaska Steller sea lions (Eumetopias jubatus)
Authors: Stegall Vicki K. , Farley Sean D. , Rea Lorrie D. , Pitcher Kenneth W. , Rye Robert O. , Kester Cynthia L. , Stricker Craig A. , Bern Carleton R.
Published: March 2008

Knowledge of diet–tissue stable isotope discrimination is required to properly interpret stable isotope values and to identify possible diet shifts, such as might be expected from nursing through weaning. This study compared δ13C and δ15Ν οf paired serum and vibrissal roots with those of ingested milk (n = 52) from free-ranging Steller sea lion ( Eumetopias jubatus (Schreber, 1776)) pups (1–11 months) and juveniles (14–27 months) to estimate diet–tissue discrimination. Mean 15N enrichment from ingested milk to serum was 2.1‰ ± 0.6‰ and δ15Ν at the root of the vibrissae (representing current growth) were not significantly different from serum values. Milk was enriched for mean 13C by 5.0‰ ± 1.0‰ and 7.3‰ ± 1.2‰ relative to serum and vibrissal roots, respectively, which was due to the presence of 13C-depleted lipids in milk. This was confirmed by lipid extraction from a subset of milk and serum samples, resulting in a 5.8‰ ± 1.0‰ change only in milk. This study established that vibrissal roots and serum are reflective of a milk diet with approximately 2.0‰ 15N enrichment, and vibrissal roots reflect serum and lipid-extracted milk values with approximately 2.0‰ 13C enrichment. These discrimination factors are important to establish for stable isotope studies assessing diet shifts.
Second reply to the comment by Romero and Kannada on “Genetic analysis of 16th-century whale bones prompts a revision of the impact of Basque whaling on right and bowhead whales in the western North Atlantic”Appears in Can. J. Zool.84(7): 1059–1065.
Authors: Higdon Jeff W.
Published: March 2008

The comments by A. Romero and S. Kannada (2006. Can. J. Zool. 84: 1059–1065) provide a brief summary of North Atlantic whaling history as a critique of T. Rastogi et al. (2004. Can. J. Zool. 82: 1647–1654) . However, they fall far short of providing an accurate review of whaling history in this region. The authors present a number of factual errors, misuse several key sources, and make significant omissions, ultimately defeating the purpose of providing information to biologists, managers, and historians. In this comment I highlight the mistakes in their representation of the history of North Atlantic whaling for bowhead whales ( Balaena mysticetus L., 1758). There are unacceptable errors for most nations covered, and for American whaling in particular. The authors assert that over 30 000 bowhead whales were landed by Yankee whalers in the North Atlantic when the vast majority were in fact taken on the Pacific grounds. Although a summary of whaling history is an admirable goal and of potential value, it is unfortunate that the authors missed such an opportunity by failing to adequately research this topic, failing to include important citations, and by including sources that do not provide the information indicated. Providing a whaling summary with such errors and omissions only adds further confusion to an already confusing theme.
Intra- and inter-specific interactions of foraging American oystercatchers on an oyster bed
Authors: Tuckwell Joanne , Nol Erica
Published: March 2008

We compared the rates of intraspecific and interspecific kleptoparasitism of foraging American oystercatchers (Haematopus palliatus) on a commercial oyster (Crassostrea virginica) bed during two seasons and between 1979 and 1995. In 1979 most conspecific kleptoparasites were immature oystercatchers and victims were adults. Both intra- and inter-specific parasitism were more common in 1979 than in 1994 or 1995. Kleptoparasitism by conspecifics was more common than by gulls (Larus argentatus, L. marinus) but was not density dependent. Gulls primarily kleptoparasitized oystercatchers foraging on mussels (Geukensia demissa), with their longer handling times. Kleptoparasitism by gulls increased as the number of gulls on the oyster bed increased, and the presence of gulls significantly depressed intake rates and sizes of mussels taken by oystercatchers during autumn. Oystercatchers ate smaller oysters in autumn than in winter in both the presence and absence of gulls. The presence of conspecific and gull kleptoparasites changed the oystercatchers' relative preference for oysters over mussels in their diet. The presence of gulls only partly explained the oystercatchers' lower rates of intake of oysters in autumn than in winter.
Structure and evolution of the pharynx in the Temnocephalida (Platyhelminthes)
Authors: Joffe Boris I. , Solovei Irina V. , Watson Nikki A. , Cannon Lester R. G.
Published: March 2008

The structure of the pharynx was studied in the genera Didymorchis, Diceratocephala, Temnocephala, and Craspedella, using light microscopy, silver nitrate staining, and transmission electron microscopy. Based on these data, evolution of this organ within the Temnocephalida is analysed. In addition to the specific pattern of muscle fibres in the walls of the pharynx known from earlier studies, three other features characteristic of the pharynges of temnocephalids were found: (1) multisyncytial organization of the pharyngeal epithelium, (2) the presence of type 1 sensory receptors, and (3) muscle fibres incorporated into the epithelium of the pharynx. Features deduced to be characteristic of the pharynx in primitive temnocephalids are (i) the presence of three types of sensory receptors with specific morphologies and locations in the pharynx, (ii) the presence of a bundle of muscle fibres that traverses the epithelium surrounding the anterior margin of the pharynx, (iii) characteristic lamellation of the epithelium of the pharynx proper, and (iv) a narrow syncytium nesting the openings of the pharyngeal glands and forming deep invaginations into which the gland ducts open. The most prominent tendencies in the evolution of the pharynx are reinforcement of the pharyngeal musculature (related to the mode of feeding) and reduction in the number of syncytia.
Consequences of larval tapeworm infection for the fitness of the intermediate hosts, flour beetles (Tribolium spp.)
Authors: Yan Guiyun
Published: March 2008

The problem of the effect of parasites on the fitness of their hosts is central to understanding the ecological and evolutionary consequences of parasitism. This study examined the consequences of infection with a tapeworm parasite, Hymenolepis diminuta, on the fitness of its intermediate hosts, Tribolium castaneum and T. confusum, and the correlation between host fitness and infection intensity. Fitness was measured as the proportion of offspring contributed by a focal individual in a test population, using beetle body colors as genetic markers. Thus, this fitness measurement estimated the overall effects on various fitness components affected by parasites, except the beetles' susceptibility to predation by definitive hosts or to parasitism by other parasites. Three different methods of infection were used to produce various levels of parasite intensity. Overall, the tapeworm infection significantly reduced the beetles' fitness, by 9–16% for T. confusum and 29–32% for T. castaneum, and parasite-induced fitness changes varied between the sexes and infection methods. The greater fitness reduction in infected T. castaneum was probably associated with its greater susceptibility to the parasite. The negative correlation between beetle fitness and infection intensity was statistically significant for T. castaneum but not for T. confusum. The significant between-species variation in parasite pathogenicity suggests that the tapeworm parasite could influence competition between beetle species in ways that might benefit T. confusum. The evolution of parasite virulence in intermediate hosts is discussed.
Familiarity and gender influence social preferences in prairie voles (Microtus ochrogaster)
Authors: DeVries A. Courtney , Johnson Camron L. , Carter C. Sue
Published: March 2008

The physiological mechanisms influencing group cohesion and social preferences are largely unstudied in prairie voles (Microtus ochrogaster). In nature, prairie vole family groups usually consist of an adult male and female breeding pair, one or more litters of their offspring, and occasionally unrelated adults. Pair bonds, defined by heterosexual preferences, develop in male and female prairie voles following cohabitation or mating. However, social preferences between members of the same sex also may be important to the maintenance of communal groups. In the present study we compared the development of social preferences for conspecific strangers of the same sex versus preferences for the opposite sex, and examined the effect of the gonadal status of the stimulus animal on initial social preference. The present study revealed that reproductively naive males, but not females, showed initial preferences for partners of the opposite sex. In both sexes preferences for the opposite sex were not influenced by the presence or absence of gonadal hormones. Heterosexual and same-sex preferences for a familiar individual formed following 24 h of nonsexual cohabitation in both males and females. Male and female same-sex preferences, however, were no longer stable when the stranger in the preference test was of the opposite sex to the experimental animal. The development of same-sex preferences may help to maintain group cohesion, but same-sex preferences formed by cohabitation do not withstand the challenge of an opposite-sex stranger.
Growth-enhanced transgenic salmon can be inferior swimmers
Authors: Farrell Anthony P. , Bennett William , Devlin Robert H.
Published: March 2008

We examined the consequence of remarkably fast growth rates in transgenic fish, using swimming performance as a physiological fitness variable. Substantially faster growth rates were achieved by the insertion of an "all-salmon" growth hormone gene construct in transgenic coho salmon (Oncorhynchus kisutch). On an absolute speed basis, transgenic fish swam no faster at their critical swimming speed than smaller non-transgenic controls, and much slower than older non-transgenic controls of the same size. Thus, we find a marked trade-off between growth rate and swimming performance, and these results suggest that transgenic fish may be an excellent model to evaluate existing ideas regarding physiological design.
SPECTRUM OF BARYONS AND SPIN–ISOSPIN DEPENDENCE
Authors: HASSANABADI H. , RAJABI A. A. , ZARRINKAMAR S.
Published: March 2008

The constituent quark model (CQM) has recently been widely used for the description of the internal structure of baryons. The baryon spectrum is usually well described, although various models are quite different. However, the study of baryon spectroscopy is not sufficient to distinguish among the various forms of quark dynamics. It would be interesting to consider the effect of an extra residual interaction among the quarks, which contains a dependence on isospin (or flavor). In the chiral constituent quark model the non-confining part of the potential is provided by the interaction with the Goldstone bosons, giving rise to a spin- and isospin-dependent part which is crucial for the description of the spectrum for energies lower than 1.7 GeV. In this work we have introduced an improved form of the hyperfine interaction and isospin dependent quark potential. The resulting description of the baryon spectrum was found to be satisfactory and we not only have included confinement potential at large separations, but also color charge and non-confining hyperfine interaction potentials. This combination of potentials yields spectra which are very close to the ones obtained in experiments.
TOP QUARK SPIN POLARIZATION IN eγ COLLISION
Authors: ŞAHIN B. , ŞAHIN İ.
Published: March 2008

We investigate the degree of spin polarization of single top quarks in the eγ collision via the process [Formula: see text] with center-of-mass energies [Formula: see text], 1 and 1.5 TeV of the parental linear e+e- collider. Dominant spin fractions and spin asymmetries for the various top quark spin bases are investigated. We show that e+-beam direction is the favorite top quark spin decomposition axis. It is found to be comparable with the ones in pp and ep collisions.
EIGENFREQUENCIES OF NODELESS ELASTIC VIBRATIONS LOCKED IN THE CRUST OF QUAKING NEUTRON STAR
Authors: BASTRUKOV S. I. , CHANG H.-K. , CHEN G.-T. , MOLODTSOVA I. V.
Published: March 2008

The Newtonian solid-mechanical theory of non-compressional spheroidal and torsional nodeless elastic vibrations in the homogenous crust model of a quaking neutron star is developed and applied to the modal classification of the quasi-periodic oscillations (QPOs) of X-ray luminosity in the aftermath of giant flares in SGR 1806-20 and SGR 1900+14. Particular attention is given to the low-frequency QPOs in the data for SGR 1806-20 whose physical origin has been called into question. Our calculations suggest that unspecified QPOs are due to nodeless dipole torsional and dipole spheroidal elastic shear vibrations.