bluuebunny/crossref_metadata_2025 huggingface dataset:
Surgical treatment of a vertebral fracture associated with a haematogenous osteomyelitis in a dog
Authors: Moissonnier P. , Cabassu J.
Published: July 2007

A seven-month-old Rottweiler was referred for a diagnosed femoral neck fracture and a suspected vertebral fracture. The simplified neurological examination revealed an acute paraplegia. A discospondyilitis associated with a pathologic fracture of Th11 and a spinal compression, and a haematogenous epiphysitis of the femoral neck were diagnosed based on radiographic and computed tomographic examinations. The vertebral fracture was stabilised using screws and polymethylmetacrylate with gentamycin by a lateral intercostal approach. The dog was able to walk seven days later. A femoral head and neck ostectomy was performed two weeks later. Staphylococcus intermedius was isolated from both sites, which confirmed the diagnosis. The dog was treated with cephalexin (30 mg/kg/d) for six weeks. A telephone interview with owners indicated that no more clinical signs were present four months after the second surgery. Discospondylitis associated with haematogenous osteomyelitis has only been reported in two cases. Paraplegia is an unusual clinical presentation for discospondylitis. The lateral approach (which allowed a direct access to the infected site) and the technique (screws associated with antibiotic-impregnated cement) are unique for surgical treatment of discospondylitis. Although applying cement to an infected area may pose a risk, antibiotic-loaded cement is successfully used in the treatment of chronic osteomyelitis in humans.
Retroperitoneal hemangiosarcoma causing chronic hindlimb lameness in a dog
Authors: Rossmeisl J. H. , Waldron D. R. , Tromblee T. C. , Jones J. C.
Published: July 2007

The clinical, radiographic, ultrasonographic, computed tomographic, surgical and histopathological findings in a Boxer dog with retroperitoneal hemangiosarcoma are described in this study. A seven-year-old, male, castrated Boxer dog was referred for evaluation of chronic hindlimb lameness. The physical examination revealed muscle atrophy and sciatic nerve deficits. Radiography and ultrasonography revealed a caudodorsal abdominal mass. Computed tomography revealed that the mass involved the left margin of the L7 vertebra, lumbosacral canal, and lumbosacral plexus. At surgery, a large retroperitoneal haematoma was removed. Histopathology of amorphous tissue found near the haematoma was consistent with haemangiosarcoma. The owner declined any further treatment. Ten weeks after discharge, the dog was euthanatized due to collapse and haemoabdomen.
Canine hip dysplasia radiographic screening. Prevalence of rotation of the pelvis along its length axis in 7,012 conventional hip extended radiographs
Authors: Cachon T. , Fau D. , Carozzo C. , Viguier E. , Collard F. , Remy D. , Genevois J.-P.
Published: July 2007

The prevalence of rotation of the pelvis along its length axis was noted, as was the number of rotations towards the right or left hand side of the dog, on 7,012 conventional hip extended radiographs, which were sent for official screening. 29.8% of the radiographs showed a rotation the pelvis. The rotation was statistically more frequent towards the left hand side of the dog. The number of rejected radiographs for too important pelvis rotation was only 5.2%. The consequences of the pelvis rotation on the Norberg-Olsson angle, on the dorsal femoral head coverage, and in the aspect of cranial acetabular edge have to be taken into account when scoring the dog for hip dysplasia.
A comparison of outcomes following tibial plateau levelling osteotomy and cranial tibial wedge osteotomy procedures
Authors: Brown C. , Corr S. A.
Published: July 2007

The objective of this study was to determine whether clinical outcomes were superior and complication rates were lower in dogs that had had a cranial cruciate ligament rupture treated by tibial plateau levelling osteotomy (TPLO), compared to those dogs that had been treated using the original cranial tibial wedge osteotomy (CTWO) procedure. Thirty-seven client-owned dogs with cranial cruciate ligament rupture were included in the study: 19 dogs underwent a TPLO procedure, and 18 dogs underwent a CTWO procedure. The study was retrospective, with the data being obtained from medical records and a review of radiographs. The long-term outcome was assessed by means of an owner questionnaire using a visual analogue scale. For the majority of factors that were reviewed, there was not a significant difference in outcome between the dogs that had a TPLO or those that had undergone a CTWO. All of the dogs showed a rapid return to weight bearing after surgery, and at the six week re-examination, the majority of the dogs did not have any pain on stifle palpation. They displayed a good stifle range of motion and significantly lower lameness scores than those prior to surgery. The complication rates did not differ between the procedures, however, within this small sample of dogs, complications following a CTWO were more likely to require revision surgery.
Chronic Immune Reactivity Against Persisting Microbial Antigen in the Vasculature Exacerbates Atherosclerotic Lesion Formation
Authors: Krebs Philippe , Scandella Elke , Bolinger Beatrice , Engeler Daniel , Miller Simone , Ludewig Burkhard
Published: July 2007

Objective—

The purpose of this study was to examine the relative contribution of different immunopathological mechanisms during murine cytomegalovirus (MCMV)-mediated acceleration of atheroma formation in apolipoprotein E–deficient (apoE
−/−
) mice.

Methods and Results—

To distinguish between the effects of systemic activation and cognate immune reactivity against a pathogen-derived persisting antigen in the vasculature, we used hypercholesterolemic transgenic mice constitutively expressing the β-galactosidase (β-gal) transgene in the cardiovascular system (apoE
−/−
×SM-LacZ). After infection with β-gal–recombinant MCMV-LacZ, apoE
−/−
, and apoE
−/−
×SM-LacZ mice mounted comparable cellular immune responses against the virus. β-gal–specific CD8
+
T cells expanded rapidly and remained detectable for at least 100 days in both mouse strains. However, compared with apoE
−/−
mice, apoE
−/−
×SM-LacZ mice developed drastically accelerated atherosclerosis. Moreover, atherosclerotic lesions in MCMV-LacZ–infected apoE
−/−
×SM-LacZ but not apoE
−/−
mice were associated with pronounced inflammatory infiltrates.

Conclusions—

Taken together, our data indicate that chronic immune reactivity against pathogen-derived antigens persisting in the vasculature significantly exacerbates atherogenesis.
Intravenous Alteplase for Stroke
Authors: De Keyser Jacques , Gdovinová Zuzana , Uyttenboogaart Maarten , Vroomen Patrick C. , Luijckx Gert Jan
Published: July 2007

Background and Purpose—

Because of the risk of hemorrhage, especially in the brain, thrombolytic therapy with intravenous alteplase is restricted by guidelines, and only a small number of selected patients are being treated. Findings from metaanalyses, post hoc analyses of the randomized trials, and postlicensing experience suggest that more subjects, who otherwise have a poor predicted outcome without treatment, might benefit from intravenous alteplase.

Summary of Review—

There is a strong indication that treatment may still be beneficial beyond 3 hours up until 4.5 hours. The risk of symptomatic intracerebral hemorrhage is not increased in patients aged 80 years or older. Excluding patients with severe stroke or with early ischemic changes in more than one third of the middle cerebral artery territory on baseline CT scan is probably not necessary when treatment is started <3 hours of symptom onset. Patients with minor or improving symptoms can also benefit. Intravenous thrombolysis appears appropriate as first line therapy for posterior circulation stroke. Alteplase can be given to patients with cervical artery dissection, seizure at onset and evidence of acute ischemia on brain imaging, and after carefully weighing risk and benefit in pregnancy and during menstruation. There are anecdotal reports on its use in children, patients with recent myocardial infarction, cardiac embolus, intracranial aneurysm or arteriovenous malformation, prior stroke and recent surgery. There appears to be a substantially increased risk of symptomatic cerebral hemorrhage in hyperglycemic stroke patients. The combined intravenous and intraarterial approach to recanalization appears safe and is currently under investigation in a randomized trial.

Conclusions—

This document does not intend to change the guidelines but reviews the literature on the use of intravenous alteplase for stroke beyond guidelines and in particular conditions.
South Asian Patients With Ischemic Stroke
Authors: De Silva Deidre A. , Woon Fung-Peng , Lee Moi-Pin , Chen Christopher P.L.H. , Chang Hui-Meng , Wong Meng-Cheong
Published: July 2007

Background and Purpose—

South Asians are the most prevalent ethnic group in the world. Intracranial disease is the most common vascular lesion worldwide.

Methods—

We prospectively studied 200 consecutive ethnic South Asian patients with acute ischemic stroke in Singapore.

Results—

Intracranial large-artery disease was prevalent among 54% of all stroke subtypes and was independently associated with hypertension and higher serum erythrocyte sedimentation rate.

Conclusions—

Among ethnic South Asian patients with ischemic stroke, intracranial large arteries are the predominant site of disease.
Discriminatory European Union Membership and the Redistribution of Enlargement Gains
Authors: Plümper Thomas , Schneider Christina J.
Published: July 2007

Conflicts between European Union (EU) members about enlargement result from its redistributive effects. EU members are more likely to suffer from enlargement if they profit from EU transfers and if they are relatively close to applicant countries in which unemployment is significantly higher than in member countries. Phasing in membership rights serves to compensate the relative losers of enlargement to accomplish EU widening. Using data from all previous enlargement rounds until 2004, we demonstrate that EU members are more likely to demand a discrimination of new members if distributional conflicts arise. The existence of these distributional conflicts in turn increases the odds of EU members and the accession candidates actually agreeing on a phase-in period.
Power
Authors: Jun Xiang  , Xiaohong Xu  , Keteku George
Published: July 2007

We join the debate on trade interdependence and conflict with a reexamination of Barbieri's (1996) intriguing empirical results showing that under certain circumstances, trade interdependence causes conflict. We argue that these findings resulted from a specification that was missing a variable. We return to Barbieri's models and introduce two independent power measures for countries within each dyad. When a correctly specified trade-conflict regression model incorporating the new power variables is performed, the constraining effect of interdependence becomes evident, and the results obtained are the reverse of Barbieri's.
When Do Conflicting Political Relations Affect International Trade?
Authors: Kastner Scott L.
Published: July 2007

Limited commercial integration between India and Pakistan or within much of the Middle East suggests that conflicting political interests between countries can have a detrimental effect on their economic relations. But rapidly growing economic ties between Mainland China and Taiwan show that commerce can also flourish even in the presence of very hostile relations. I explore this variation and hypothesize that the effects of international political conflict on trade are less severe in cases where internationalist economic interests have relatively strong political clout domestically. Simple quantitative tests on a sample of seventy-six countries over the years 1961 to 1992 are supportive; further evidence is provided via a brief case study of Mainland China-Taiwan relations.
The Oral, Once‐Daily Phosphodiesterase 4 Inhibitor Roflumilast Lacks Relevant Pharmacokinetic Interactions With Inhaled Budesonide
Authors: Hermann Robert , Siegmund Werner , Giessmann Thomas , Westphal Kristin , Weinbrenner Anita , Hauns Bernhard , Reutter Felix , Zech Karl , Lahu Gezim , Bethke Thomas D.
Published: July 2007

This open‐label, randomized, 3‐period crossover study evaluated the pharmacokinetic interaction potential of roflumilast and budesonide following repeated coadministration to healthy male subjects (N = 12). Treatments consisted of oral roflumilast 500 μg, once daily, orally inhaled budesonide 800 μg, twice daily, and concomitant administration of both treatments for 7 days each. Roflumilast and roflumilast N‐oxide in plasma and budesonide serum levels were measured by specific assays. Geometric mean test/reference ratios of steady‐state pharmacokinetic parameters were evaluated by analysis of variance. Safety and tolerability were monitored. Pharmacokinetic parameters of roflumilast, roflumilast N‐oxide, and budesonide after coadministration of roflumilast and budesonide were similar to those after mono‐treatment. Compared with budesonide and roflumilast mono‐treatments, slightly lower maximum serum/plasma concentration (Cmax) and area under the curve (AUC) values of roflumilast N‐oxide and budesonide (ranging from −8% to −16%) were observed with combined treatment. All test/reference ratios were within predefined equivalence acceptance ranges for roflumilast AUC (0.80, 1.25) and Cmax(0.70, 1.43) and for roflumilast N‐oxide and budesonide AUC and Cmax(all 0.67, 1.50). Coadministration of roflumilast and budesonide did not alter the steady‐state disposition of each other and did not affect safety and tolerability of either drug.
Evaluation of Pharmacokinetic Interactions Between Vildagliptin and Digoxin in Healthy Volunteers
Authors: He Yan‐Ling , Sabo Ron , Sunkara Gangadhar , Bizot Marie‐Noëlle , Riviere Gilles‐Jacques , Leon Selene , Ligueros‐Saylan Monica , Dole William P. , Howard Dan
Published: July 2007

Vildagliptin is a novel antidiabetic agent that is an orally active, potent, and selective inhibitor of dipeptidyl peptidase IV, the enzyme responsible for degradation of the incretin hormones. This open‐label, randomized, 3‐period crossover study investigated the potential for pharmacokinetic interactions in 18 healthy subjects during coadministration of vildagliptin and digoxin. Subjects were randomized to receive each of 3 treatments: vildagliptin 100 mg qd, digoxin (0.5 mg, then 0.25 mg qd on days 2–7), and the combination vildagliptin/digoxin for 7 days. Coadministration of digoxin with vildagliptin had no effect on exposure to vildagliptin (geometric mean ratios [90% confidence interval]: AUC0‐24h, 0.99 [0.95–1.03]; Cmax, 0.95 [0.85–1.06]) or to digoxin (AUC0‐24h, 1.02 [0.94–1.12]; Cmax, 1.08 [0.97–1.20]). In addition, no changes in tmax, t1/2, and CL/F were observed for either drug. These results indicate that no dose adjustment is necessary when vildagliptin and digoxin are coadministered.
Contrasting Time‐ and Rate‐Based Approaches for the Assessment of Drug‐Induced QT Changes
Authors: Extramiana Fabrice , Badilini Fabio , Sarapa Nenad , Leenhardt Antoine , Maison‐Blanche Pierre
Published: July 2007

The authors aim to highlight the pitfalls of different validated methods used for the assessment of drugs' effect on QT duration. Digital 12‐lead Holter electrocardiograms were recorded at baseline and after a single dose of sotalol in 39 healthy subjects (age = 27.4 ± 8.0 years). Using both time‐ and rate‐based approaches, the authors obtained averaged QRS‐T complexes every minute (“time bins”) and at different RR intervals (“rate bins”). Time bins were corrected for heart rate using a subject‐specific approach. The individual α coefficients increased from placebo (0.309 ± 0.052) to sotalol (0.454 ± 0.136), P < .0001. When the placebo individual α coefficients were applied to correct the QT interval on sotalol, the changes were >5 ms smaller than those obtained using the ON drug α coefficients. The “rate”‐averaging process leads to a complete loss of the time course of drug effect. In conclusion, the individual correction formula calculated from the placebo condition cannot always be used for QT correction on the drug.
Dose Proportionality and the Effect of Food on Vildagliptin, a Novel Dipeptidyl Peptidase IV Inhibitor, in Healthy Volunteers
Authors: Sunkara Gangadhar , Sabo Ron , Wang Yibin , He Yan‐Ling , Campestrini Joelle , Rosenberg Mitchell , Howard Dan , Dole William P.
Published: July 2007

Vildagliptin is a potent and selective dipeptidyl peptidase IV inhibitor in development for the treatment of type 2 diabetes that improves glycemic control by enhancing α‐ and β‐cell responsiveness to glucose. Two open‐label, single‐dose, randomized, crossover studies in healthy subjects (ages 18–45 years) investigated the dose proportionality of vildagliptin pharmacokinetics (n = 20) and the effect of food (n = 24) on vildagliptin pharmacokinetics. There was a linear relationship (r2 = 0.999) between vildagliptin doses of 25, 50, 100, and 200 mg and area under the plasma concentration‐time curve from time zero to infinity (AUC0–∞) and maximum plasma concentration (Cmax). Dose proportionality was assessed using a statistical power model [X = α·(dose)β]. The 90% confidence intervals of the proportionality coefficient, β, for AUC0–∞ (1.15–1.19) and Cmax (1.04–1.14) indicated that deviations from dose proportionality were small (<7.7%). Doubling of dose led to 2.1‐ to 2.3‐fold increases in AUC0–∞ and Cmax but no dose‐dependent changes in time to reach Cmax or terminal elimination half‐life. Administration of vildagliptin 100 mg following a high‐fat meal decreased Cmax by 19% and AUC0–∞ by 10%. Vildagliptin displays approximately dose‐proportional pharmacokinetics over the 25‐ to 200‐mg dose range, and administration with food has no clinically relevant effect on vildagliptin pharmacokinetics.
Psychosocial Self-Efficacy and Personal Characteristics of Veterans Attending a Diabetes Education Program
Authors: Via Patricia S. , Salyer Jeanne
Published: July 2007

PURPOSE

The purpose of this descriptive correlational study was to describe the perceived psychosocial self-efficacy, attitude toward having diabetes, baseline glucose level, and personal characteristics of male veterans with type 2 diabetes.

METHODS

The Diabetes Empowerment Scale (DES) was mailed to participants and collected on the day of the program. Percent ideal body weight and glycosylated hemoglobin were measured. Comparisons were made by educational level, racial origin, and type of medication regimen on the DES and its subscales.

RESULTS

Participants on oral medication versus insulin had higher scores in the categories of Motivation to Change and Ability to Cope with Feelings. Participants with less education had greater scores in Ability to Cope with Feelings and Obtain Support. No racial differences were seen on the measured scores; a significant difference was seen between Caucasians and non-Caucasians in baseline glycemic control.

CONCLUSIONS

Targeting intervention strategies early in the course of disease progression may positively affect outcome. Longitudinal studies are needed to demonstrate the impact of self-management training on psychosocial self-efficacy and clinical outcomes.
Diabetes Care Practices in Primary Care: Results from Two Samples and Three Measurement Sets
Authors: Glasgow Russell E. , Boles Shawn M. , Calder David , Dreyer Linda , Bagdade John
Published: July 2007

PURPOSE

here has been substantial recent interest in diabetes disease management interventions, guidelines, and care practices. As the vast majority of diabetes care occurs in primary care settings, it makes sense to evaluate current levels of recommended practices in different primary care settings.

METHODS

We report on two separate studies that included a combined total of 389 patients seen by over 30 different providers. Three different sets of recommended practices were assessed: (1) the ADA provider recognition measures, (2) the proposed Diabetes Quality Improvement Project measures, and (3) the state of Oregon Population-Based Guidelines for Diabetes.

RESULTS

In general, there was only a moderate level of adherence to recommended practices, and adherence was much lower for behavioral or patient-focused practices as contrasted with laboratory tests. There was considerable variability across providers and across different guidelines activities.

CONCLUSIONS

Policy and quality improvement implications and future research issues are discussed, including the need for studying different measurement approaches for evaluating guidelines adherence.
Articular Talar Injuries in Athletes
Authors: Saxena Amol , Eakin Colin
Published: July 2007

Background

The treatment options of talar osteochondral lesions are numerous. Although studies show these treatments have been used with varying success, the ability to return to activity (RTA), including sports after treatment of talar dome injuries, have not been well documented.

Hypothesis

A treatment plan that uses microfracture for Hepple stage 2 through 4 lesions and autogenous bone grafting for Hepple stage 5 lesions for athletes with articular lesions of the talus will produce a high rate of return to athletic activity.

Study Design

Case series; Level of evidence, 4.

Methods

Preoperative and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) scores and RTA were assessed prospectively 2 to 8 years after surgery in high-demand (athletic) patients with articular injuries to the talar dome treated according to the above protocol over a 6-year period.

Results

There were 26 microfracture procedures and 20 bone grafts to the talus. The AOFAS scores for both microfracture (preoperative, 54.6; postoperative, 94.4) and bone graft (preoperative, 46.1; postoperative, 93.4) patients improved significantly. The RTA for the entire group was 17.0 ± 5.3 weeks; for those undergoing microfracture, RTA was 15.1 ± 4.0 weeks; and for bone grafting, it was 19.6 ± 5.9 weeks. The RTA for the bone graft group was significantly slower than that of the microfracture group. Anterolateral lesions had significantly faster RTA and higher postoperative scores compared with other lesion locations. Arthroscopically treated lesions had similar postoperative AOFAS scores to those who had arthrotomy and did not have significantly faster RTA. Forty-four (96%) “excellent/good” AOFAS scores were achieved overall for talar lesions, with the same percentage of return to sport.

Conclusions

Talar bone grafting required a longer time to return to activity than microfracture in high-demand patients, but both groups had similar postoperative AOFAS scores. When applied to appropriate lesions, both techniques allow athletic patients to return to sports.
Finite Element Based Characterization of Carbon Nanotubes
Authors: Kirtania Sushen , Chakraborty Debabrata
Published: July 2007

In the present study 3D finite element (FE) analysis has been used to evaluate Young's modulus, shear modulus and coefficient of thermal expansion (CTE) of single-walled carbon nanotubes (SWCNTs). Both armchair and zigzag SWCNTs have been analyzed and some important observations have been made in regard to dependence of elastic moduli and CTE of SWCNTs on important parameters.
The Effect of Transverse Shear, Rotary Inertia on Wave Propagation in Laminated Piezoelectric Cylindrical Shells in Thermal Environment
Authors: Dong K. , Wang X.
Published: July 2007

The effects of transverse shear, rotary inertia and thermal loads on wave propagation in orthotropic laminated piezoelectric cylindrical shells are studied in this paper. A dynamic model of laminated piezoelectric cylindrical shell is derived based on Cooper-Naghdi shell theory. The wave characteristics curves are obtained by solving an eigenvalue problem. Besides discussing the dispersion curves for different wave modes, effects of layer numbers, the thickness of piezoelectric layers and thermal environment on the wave characteristics curves were also studied. This solution method is validated by the classical solution of an elastic shell, and may be used to investigate wave propagation in laminated piezoelectric cylindrical shells with various laminated materials, layer numbers and thickness, in thermal environment.
An Experimental Investigation on the Impact Response of Fiberglass/Aluminum Composites
Authors: Atas Cesim
Published: July 2007

This paper presents experimental investigations on impact response of fiberglassaluminum (FGA) composites. A number of test specimens were subjected to increasing impact energies until complete perforation of the target was achieved. The damage process of fiber-glass aluminum (FGA) composites is examined by comparing the load-deflection curves, energy profile diagram (showing the correlation between impact energy and absorbed energy) and images of damaged specimens. The failure processes in the impact-loaded FGAs were initially investigated by examining the front and rear surfaces of the damaged samples. After initial examination, damage mechanisms at the interior layers were ascertained through destructive analysis, i.e., sectioning and de-plying, of samples. Careful examination of the damaged FGA panels highlighted a number of failure mechanisms such as permanent plastic deformation, tearing and shear fracture in the aluminum layers as well as fiber fracture in glass-epoxy layers, and delamination between adjacent layers, i.e., at composite/composite and composite/metal interfaces. Along with the cross-sections, images of several impacted samples for varied impact energies are provided for discussion.
Nonlinear Finite Element Analysis of Laminated Composite Doubly Curved Shells in Hygrothermal Environment
Authors: Kundu C.K. , Maiti D.K. , Sinha P.K.
Published: July 2007

In the present investigation, the geometrically nonlinear analysis of laminated doubly curved shells in a hygrothermal environment is presented using the finite element method. The laminated composite shells may be exposed to moisture and temperature during their service life. Hygrothermal effects induce residual stresses and the laminated shell may undergo large bending deformation. The shell geometry used in the formulation is derived using the orthogonal curvilinear coordinate system. Based on the principle of virtual work the nonlinear finite element equations are derived. A total Lagrangian approach associated to the arc-length method is implemented to solve the equilibrium equations. The present results are found to compare well with those available in the open literature and parametric studies are performed to analyze the nonlinear deflections of [0°/±45°/90°]s laminated spherical, cylindrical and conoidal shell panels under hygrothermal condition.
Buckling Optimization of Composite Columns with Variable Thickness
Authors: Pekbey Y. , Ozdamar A. , Sayman O.
Published: July 2007

A novel approach to the optimization of flexible columns against buckling is presented. The problem of determining the shape of the column that has possibly the largest critical buckling load of columns of a given length and volume is solved for composite materials. The objective of this study was to develop and design an optimized composite column against buckling. Determining what shape of column has the largest possible buckling load of composite column of a given length and volume was considered. Clamped—clamped supported column is an important limit case because it caused debate in many publications. Moreover, in this study, the optimization problem of the clamped—clamped column under buckling load, which was previously dealt with by Tadjbakhsh and Keller [5], Olhoff and Rasmussen [6] and Masur [7] is reinvestigated. It is also proved that the solutions of Tadjbakhsh and Keller, Olhoff and Rasmussen and Masur are not optimum for columns with clamped ends. The present model formulation considers columns for which crush is taken into account in the formulation of the column optimization problem, allowing for bimodal optimum solution. This leads to the necessity for both stability and crush criterion formulation of the optimization problem. The new proposed optimum model solution has been verified with numerical analysis using ANSYS and experimental data for columns with clamped—clamped ends. It was shown that the new proposed model was given the optimum solution for the clamped—clamped case. Detailed results are presented and discussed for clamped—clamped columns having circular cross-sectional configuration. As a result of this study, it was shown that results obtained in previous studies of variation optimum cross-sectional area for columns under compressive forces clamped—clamped ends were erroneous. The corrected optimum form was obtained and results checked by numerical calculations and experimental tests of composite columns.
Nonlinear Free Vibration Analysis of Laminated Composite Cylindrical Shells with Cutouts
Authors: Nanda Namita , Bandyopadhyay J.N.
Published: July 2007

The nonlinear free vibration of laminated composite cylindrical shell panels in the presence of cutouts is investigated. The finite element model using an eight-noded C0 continuity, isoparametric quadrilateral element is used to study the dynamic behavior. The nonlinear eigenvalue problem is solved by using the direct iteration method. Parametric study is carried out varying the aspect ratios, lamination schemes and material properties of cylindrical shell with simply supported boundary condition in the presence of cutouts.
Monitoring Circadian Rhythms of Individual Honey Bees in a Social Environment Reveals Social Influences on Postembryonic Ontogeny of Activity Rhythms
Authors: Meshi A. , Bloch G.
Published: July 2007

Social factors constitute an important component of the environment of many animals and have a profound influence on their physiology and behavior. Studies of social influences on circadian rhythms have been hampered by a methodological trade-off: automatic data acquisition systems obtain high-quality data but are effective only for individually isolated animals and therefore compromise by requiring a context that may not be sociobiologically relevant. Human observers can monitor animal activity in complex social environments but are limited in the resolution and quality of data that can be gathered. The authors developed and validated a method for prolonged, automatic, high-quality monitoring of focal honey bees in a relatively complex social environment and with minimal illumination. The method can be adapted for studies on other animals. The authors show that the system provides a reliable estimation of the actual path of a focal bee, only rarely misses its location for > 1 min, and removes most nonspecific signals from the background. Using this system, the authors provide the first evidence of social influence on the ontogeny of activity rhythms. Young bees that were housed with old foragers show ~24-h rhythms in locomotor activity at a younger age and with stronger rhythms than bees housed with a similar number of young bees. By contrast, the maturation of the hypopharyngeal glands was slower in bees housed with foragers, similar to findings in previous studies. The morphology and function of the hypopharyngeal glands vary along with age-based division of labor. Therefore, these findings indicate that social inhibition of task-related maturation was effective in the experimental setup. This study suggests that although the ontogeny of circadian rhythms is typically correlated with the age-based division of labor, their social regulation is different.
Multiple Mechanisms Regulate Circadian Expression of the Gene for Cholesterol 7α-Hydroxylase (Cyp7a), a Key Enzyme in Hepatic Bile Acid Biosynthesis
Authors: Noshiro Mitsuhide , Usui Emiko , Kawamoto Takeshi , Kubo Hiroshi , Fujimoto Katsumi , Furukawa Masae , Honma Sato , Makishima Makoto , Honma Ken-ichi , Kato Yukio
Published: July 2007

Cholesterol 7α-hydroxylase (CYP7A) and sterol 12α-hydroxylase (CYP8B) in bile acid biosynthesis and 3-hydroxyl-3-methylglutaryl CoA reductase (HMGCR) in cholesterol biosynthesis are the key enzymes in hepatic metabolic pathways, and their transcripts exhibit circadian expression profiles in rodent liver. The authors determined transcript levels of these enzymes and the regulatory factors for Cyp7a—including Dbp, Dec2, E4bp4, Hnf4α, Pparα, Lxrα, Rev-erbα, and Rev-erbβ—in the liver of wild-type and homozygous Clock mutant mice ( Clock/Clock) and examined the effects of these transcription factors on the transcription activities of Cyp7a. The expression profile of the Cyp7a transcript in wild-type mice showed a strong circadian rhythm in both the 12L:12D light-dark cycle and constant darkness, and that in Clock/Clock also exhibited a circadian rhythm at an enhanced level with a lower amplitude, although its protein level became arrhythmic at a high level. The expression profile of Cyp8b mRNA in wild-type mice showed a shifted circadian rhythm from that of Cyp7a, becoming arrhythmic in Clock/Clock at an expression level comparable to that of wild-type mice. The expression profile of Hmgcr mRNA also lost its strong circadian rhythm in Clock/Clock , showing an expression level comparable to that of wild-type mice. The expressions of Dbp, Dec2, Rev-erbα, and Rev-erb β—potent regulators for Cyp7a expression—were abolished or became arrhythmic in Clock/Clock, while other regulators for Cyp7a— Lxrα, Hnf4α, Pparα, and E4bp4—had either less affected or enhanced expression in Clock/Clock. In luciferase reporter assays, REV-ERBα/β, DBP, LXRα, and HNF4α increased the promoter activity of Cyp7a, whereas DEC2 abolished the transcription from the Cyp7a promoter: E4BP4 and PPARα were moderate negative regulators. Furthermore, knockdown of REV-ERBα/β with siRNA suppressed Cyp7a transcript levels, and in the electrophoretic mobility shift assay, REV-ERBα/β bound to the promoter of Cyp7a . These observations suggest that (1) active CLOCK is essential for the robust circadian expression of hepatic metabolic enzymes ( Cyp7a, Cyp8b, and Hmgcr); (2) clock-controlled genes—DBP, DEC2, and REV-ERBα/β—are direct regulators required for the robust circadian rhythm of Cyp7a; and (3) the circadian rhythm of Cyp7a is regulated by multiple transcription factors, including DBP, REV-ERBα/β, LXRα, HNF4α DEC2, E4BP4, and PPARα.
Attenuating Effect of Clock Mutation on Triglyceride Contents in the ICR Mouse Liver under a High-Fat Diet
Authors: Kudo Takashi , Tamagawa Toru , Kawashima Mihoko , Mito Natsuko , Shibata Shigenobu
Published: July 2007

Energy homeostasis is subjected to a circadian control that synchronizes energy intake and expenditure. The transcription factor CLOCK, a key component of the molecular circadian clock, controls many kinds of rhythms, such as those for locomotor activity, body temperature, and metabolic functions. The purpose of the present study is to understand the function of the Clock gene during lipid metabolism in the liver using Clock-mutant mice. Clock-mutant mice with an ICR background were fed a high-fat diet for 13 weeks, and liver triglyceride, serum triglyceride, and serum free fatty acid levels were examined. Triglyceride content in the liver was significantly less increased in Clock-mutant mice on a high-fat diet compared to wild-type mice on a high-fat diet. Acsl4 and Fabp1 mRNA levels in the liver showed daily rhythms in wild-type mice. In contrast, Clock -mutant mice had attenuated daily rhythms of Acsl4 and Fabp1 gene expression in the liver under both normal and high-fat diet conditions compared to wild-type mice. In Clock-mutant mice, suppression of Acsl4 and Fabp1 mRNA in the liver under high-fat diet conditions may have attenuated the accumulation of triglycerides in the liver compared to wild-type mice under the same conditions. In conclusion, the authors demonstrate that mice with a Clock mutation showed less triglyceride accumulation in the liver through the suppression of Acsl4 and Fabp1 gene expression when fed a high-fat diet compared to wild-type mice fed the same diet.
Photoperiodic and Food Signals Control Expression Pattern of the Clock Gene, Period, in the Linden Bug, Pyrrhocoris apterus
Authors: Doležel David , Šauman Ivo , Košt'ál Vladimír , Hodkova Magdalena
Published: July 2007

The temporal expression pattern of the circadian clock gene period was compared between heads of the linden bug, Pyrrhocoris apterus , kept under diapause-promoting short days (SD) and diapause-preventing long days (LD) using a real-time PCR quantification. Diapause or reproduction was programmed by photoperiod during the larval stage, but the first difference in per mRNA abundance between SD and LD insects was observed only after adult ecdysis. The expression level of per mRNA was markedly higher, up to more than 10-fold, in the destined-to diapause animals compared with those scheduled for reproduction. Up-regulation of per transcript was restricted to an early diapause peak, with the maximum expression on days 3 to 5 after adult ecdysis. Starvation reduced the peak level of per mRNA to about 50% of the value found in feeding females in the SD conditions, but per mRNA abundance was similarly low in fasting and feeding females in LD. Photoperiodic refractoriness in either wild-type postdiapause adults or in a selected nondiapause variant of P. apterus was associated with reproduction and low, LD-like levels of per mRNA under both SD and LD. Overall, the data suggest that the photoperiodic programming itself has no direct effect on per mRNA abundance, but it does determine the response of per transcript to food signals during subsequent expression of diapause/reproduction physiology.
Unpacking Unintended Consequences in Planned Organizational Change: A Process Model
Authors: Guowei Jian
Published: July 2007

The author develops a process model of the unintended consequences in planned organizational change that draws on the structuration, organizational change, and organizational tension literatures. The model depicts the communicative actions of both senior management and employees and reveals the dynamic through which unintended consequences unfold. The model extends theoretical understandings of planned organizational change and discusses how future research can build a dialectic and dialogic model of planned change focused on employee participation. The author illustrates the model with a case study of organizational change and its unintended consequences. The article concludes with insights on change management for practitioners and with directions for future research.
The Impact of Communal Knowledge Repositories and People-Based Knowledge Management on Perceptions of Team Effectiveness
Authors: Child Jeffrey T. , Shumate Michelle
Published: July 2007

Managers have increasingly implemented knowledge databases and knowledge-sharing training to improve team effectiveness. The authors examine whether intranet-based repository use and perception of accurate team knowledge of who knows what were related to perceived team effectiveness. They found that the perception that one's team had accurate who-knows-what knowledge is positively related to perceived team effectiveness. Repository use is not positively related to perceived team effectiveness. Remote work and tenure are not significant moderators of these relationships. These findings imply that perception of an accurate cognitive map of who knows what is more important to perceived team effectiveness than accessing information from repositories, regardless of remote work status or organizational tenure.
Latent class models and their application to missing-data patterns in longitudinal studies
Authors: Roy Jason
Published: July 2007

Latent class models have been developed as a flexible way of modeling the correlation of multivariate data, as a method for discovering subpopulations with similar response profiles and as a dimension reduction tool. In this manuscript, we provide a review of some of this literature and describe specific developments in several statistical and substantive areas. We then describe latent class models that could be used for characterizing missing-data patterns in longitudinal studies with regularly spaced observation times, where there is a large amount of intermittent missing data. We illustrate by analyzing data from a longitudinal study of depression, where there were 379 unique missing-data patterns.
Effective Stress and Vector-valued Orientational Distribution Functions
Authors: Yang Q. , Chen X. , Zhou W.-Y.
Published: July 2007

The original Kachanov—Rabotnov damage variable is inherently microplane-based and should be expressed by a scalar-valued orientation distribution function (ODF), and the corresponding effective stress is a vector-valued ODF. The analysis of vector-valued ODFs is established in this article in the spirit of the analysis of scalar-valued ODFs by Kanatani, K. (1984a). Distribution of Directional Data and Fabric Tensors, International Journal of Engineering Science, 22: 149—164 and Kanatani, K. (1984b). Stereological Determination of Structural Anisotropy, International Journal of Engineering Science, 22: 531—546. Explicit expansions of vector-valued ODFs up to the sixth-order have been developed, and the relationship of fabric tensors of different order is addressed. The fabric tensors and expansion of the Kachanov—Rabotnov effective stress vector can be fully determined by the scalar-valued ODF characterizing the microplane damage. The second-order effective stress and damage tensors of Murakami, S. (1988). Mechanical Modeling of Material Damage, ASME Journal of Engineering Materials and Technology, 55: 280—286 are related to the second-order expansion of the Kachanov—Rabotnov effective stress vector. Therefore, the analysis of vector-valued ODFs furnishes a rigorous and unified mathematical basis for the damage theory of Kachanov, L.M. (1958). Time of the Rupture Process under Creep Conditions, Izv. Akad. Nauk., USSR. Otd. Tekhn. Nauk. 8: 26—31, Rabotnov, I.N. (1963). On the Equations of State for Creep, Progress in Applied Mechanics, the Prager Anniversary, 8: 307—315, and Murakami, S. (1988). Mechanical Modeling of Material Damage, ASME Journal of Engineering Materials and Technology, 55: 280—286.
Accumulation Damage Mode for Ferroelectric Ceramics Subjected to Mode III Fatigue Loading Conditions
Authors: Wang B.L. , Mai Y.-W.
Published: July 2007

Based on the accumulated plastic displacement criterion, equations to predict the fatigue crack growth of piezoelectric ceramics are developed. The medium is subjected to anti-plane mechanical and in-plane electrical loads. Under such electromechanical loading conditions, it is assumed that an electric saturation zone and an elastic yielding zone near the crack tips are developed. The accumulated plastic deformation is obtained in a closed-form, which is expressed in terms of the applied loads and material constants. A fatigue crack growth law of a fourth-power function of the effective stress intensity factor is derived. The effect of electric field load on the effective crack-tip stress intensity factor and crack growth rate are shown graphically.
Modeling Microdefects Closure Effect with Isotropic/Anisotropic Damage
Authors: Desmorat R. , Cantournet S.
Published: July 2007

Continuum damage mechanics (CDM) for metals is often written in terms of an isotropic (scalar) damage. In this case, solutions have been proposed to represent the differences of behavior in tension and in compression also called quasi-unilateral (QU) conditions or microdefects closure effect.

A recent anisotropic damage model has been developed to take into account the damage orthotropy induced by plasticity (Lemaitre, J., Demorat R. and Sauzay, M. (2000). Anisotropic Damage Law of Evolution, Eur. J. Mech. A/Solids, 19: 513—524). The purposes here are then two. First, a unified framework for isotropic and anisotropic damage is proposed. Then, it is to extend Ladevèze and Lemaitre's framework (Ladevèze, P. and Lemaitre, J. (1984). Damage Effective Stress in Quasi Unilateral Conditions, In: Proceedings of the 16th International Congress of Theoretical and Applied Mechanics, Lyngby, Denmark) for the QU conditions to anisotropic damage induced by plasticity.

Yield surfaces and damage versus accumulated plastic strain curves, drawn for different loading, illustrate the effect of the QU conditions on the damage evolution.
Chemokine stromal cell-derived factor-1 induction by C/EBPβ activation is associated with all-trans-retinoic acid-induced leukemic cell differentiation
Authors: Kim KyeongJin , Kim Hyeong Hoe , Kim Joon Hong , Choi Yung Hyun , Kim Young Hee , Cheong JaeHun
Published: July 2007

Stromal cell-derived factor-1 (SDF-1/CXCL12) is one of the essential chemokines, which mediates hematopoietic differentiations. However, the mechanism by which SDF-1 expression is regulated in granulocyte differentiation is poorly understood. Here, we suggest a novel mechanism by which all-trans-retinoic acid (ATRA) induces the expression of SDF-1 during the differentiation of promyelomonocytic leukemic U937 cells. Moreover, we also demonstrate that activation of transcription factor C/EBPβ by ATRA regulates SDF-1 expression in U937 cells. In addition, we show that the cyclin-dependent kinase inhibitors p21WAF1/CIP1 and Pyk2 are up-regulated by SDF-1 and increased markedly by the costimulation of ATRA and SDF-1. Furthermore, ATRA and SDF-1α additively induce U937 cell differentiation. Indeed, silencing the expression of SDF-1 inhibits ATRA-induced granulocyte differentiation significantly. Taken together, these results indicate that SDF-1α is involved in granulocyte differentiation in response to ATRA, mediated by the activation of the transcription factor C/EBPβ.
A discrete period of FGF-induced Erk1/2 signalling is required for vertebrate neural specification
Authors: Stavridis Marios P. , Lunn J. Simon , Collins Barry J. , Storey Kate G.
Published: July 2007

Neural tissue formation is induced by growth factors that activate networks of signal transduction cascades that ultimately lead to the expression of early neural genes, including transcription factors of the SoxB family. Here,we report that fibroblast growth factor (FGF)-induced Erk1/2 (Mapk3 and Mapk1,respectively) mitogen-activated protein kinase (MAPK), but not phosphatidylinositol 3′-OH kinase (PI3K, Pik3r1), signalling is required for neural specification in mouse embryonic stem (ES) cells and in the chick embryo. Further, blocking Erk1/2 inhibits the onset of key SoxB genes in both mouse ES cells (Sox1) and chick embryos (Sox2 and Sox3) and, in both contexts, Erk1/2 signalling is required during only a narrow time window, as neural specification takes place. In the absence of Erk1/2 signalling, differentiation of ES cells stalls following Fgf5 upregulation. Using differentiating ES cells as a model for neural specification, we demonstrate that sustained Erk1/2 activation controls the transition from an Fgf5-positive, primitive ectoderm-like cell state to a neural progenitor cell state without attenuating bone morphogenetic protein (BMP) signalling and we also define the minimum period of Erk1/2 activity required to mediate this key developmental step. Together, these findings identify a conserved, specific and stage-dependent requirement for Erk1/2 signalling downstream of FGF-induced neural specification in higher vertebrates and provide insight into the signalling dynamics governing this process.