bluuebunny/crossref_metadata_2025 huggingface dataset:
ABSTRACTS: 6 Human trophoblast: Development of double tissue confrontation assays
Authors: Gerit Moser , Regine Theuerkauf , Nina Flieser , Berthold Huppertz
Published: June 2008

Problem:  Invasion of trophoblast differs between implantation and subsequent placentation. Here we present double tissue co‐culture in vitro models for trophoblast invasion.

Material and Methods:  Pieces of decidua parietalis (6‐12 weeks gestation) were confronted directly with villous explants (direct confrontation) or after separate preculture for 72h (indirect confrontation). For “indirect confrontation” decidua pieces re‐epithelialized during preculture (constant agitation). All confrontations were harvested after 72h and were processed for immunohistochemistry.

Results:  During indirect confrontation immunohistochemical staining for HLA‐G and cytokeratin 7 revealed trophoblast migration on top of the decidual epithelium and little invasion into the decidual stroma. During direct confrontation, the same staining revealed strong invasion of extravillous trophoblasts into decidual stroma.

Conclusion:  Trophoblasts confronted to decidual epithelium seem to be less invasive than trophoblasts confronted to the decidual stroma directly. These model systems will be further used to investigate mechanisms underlying the interactions between trophoblasts and decidual epithelium/stroma.
Root healing after horizontal fracture: a case report with a 13‐year follow up
Authors: Andrade Evaristo Soares , De Campos Sobrinho Antônio Lucindo Pinto , Andrade Miguel Gustavo Setúbal , Matos Jane Luzia Freire
Published: June 2008

Abstract –  Although horizontal root fractures connote a serious trauma to the tooth, they present a favorable prognosis, as the vitality of the pulp remains. Small displacements of the fragments minimize the failure of the healing process; however, even when they occur, the reduction of the diastasis between root fragments is always necessary. A majority of cases are asymptomatic and heal spontaneously even though no therapeutic measures have been adopted. A case of root fracture that was discovered only 1 year after the trauma is presented. Thirteen years later, the tooth is well positioned in the maxillary arch and has kept its pulp vitality despite the obliteration of the root conduct. Expectant management was adopted at the moment of the first examination, and the follow‐up of the patient showed it to have been the best choice.
Multiple dentoalveolar traumatic injury: a case report (3 years follow up)
Authors: Koyuturk Alp Erdin , Kusgoz Adem
Published: June 2008

Abstract –  Dental trauma with children and adolescents is a serious dental public health problem. Traumatic injuries on permanent teeth are common, and dramatic episodes can occur during childhood. Cases of dental avulsions and reimplantations, dentoalveolar fractures, several forms (lateral, extrusive and intrusive) of luxations, concussion, subluxation, gingival lacerations and hard, pulpal dental tissue lesions have been extensively reported. This case report presents the therapy for severe trauma caused by multiple traumatic injuries to the dentoalveolar complex of a patient.
Management of subluxation injury in a thumb‐sucking child: a case report
Authors: Celik Berna , Cehreli Zafer C.
Published: June 2008

Abstract –  This case report presents use of a custom trauma splint that was fabricated to prevent excessive thumb‐sucking trauma to a previously‐subluxated permanent incisor. A 10‐year‐old boy was referred to the clinic 10 days after falling in the schoolyard that resulted in a trauma to his maxillary left central incisor. The extent of clinical mobility stipulated fabrication of a custom trauma splint that would prevent further trauma to the incisor caused by excessive pressure of the thumb. A light‐cured resin composite splint, covering the incisal edges of the central incisors and labial surfaces of the lateral incisors was made, and approximately 1‐mm composite within the impressions of central incisors were trimmed off. The splint was bonded to the neighboring lateral incisors with flowable resin composite and root canal therapy was initiated on the subluxated incisor. After one week, the patient stopped his sucking habit completely. The treatment not only allowed for complete healing of the subluxated incisor without being exposed to further trauma, but also for spontaneous eruption of the tooth and closure of the existing open‐bite.
Multidisciplinary approach to traumatized teeth: a case report
Authors: Yüzügüllü Bulem , Polat Ömür , Üngör Mete
Published: June 2008

Abstract –  Treatment of crown fractures often requires a multidisciplinary approach. In the anterior teeth, reestablishment of proper esthetics and function is quite important for the patient. However, crown‐root fractures with fracture line below the gingival attachment or alveolar bone crest presents restorative difficulties. This case report presents a cervical tooth fracture that had been treated with minimal invasive approach with different disciplines. The tooth had endodontic treatment and a glass‐fiber post, and a composite core was accomplished. Then, the tooth was extruded to the desired level with orthodontic forced eruption before definitive restoration.
Treatment of sequelae in permanent dentition after severe trauma in primary dentition
Authors: Ak Aslı Topaloglu , Eden Ece , Tasdemir Ozgun Ozcaka
Published: June 2008

Abstract –  A case with a dilacerated upper right central and hypoplastic upper right lateral incisors covered with gingiva of a 10‐year‐old female, with a history of trauma at the age of 18 months, is presented. After clinical and radiographical evaluations, esthetic problem was solved with gingivectomy followed by composite restorations of the involved teeth.
Endodontic and orthodontic treatment of fused maxillary central incisors: a case report
Authors: Ozalp Serife Ozdemir , Tuncer Burcu Baloş , Tulunoglu Ozlem , Akkaya Sevil
Published: June 2008

Abstract –  The purpose of this case report was to describe combined endodontic and orthodontic treatment of a patient who had permanent maxillary central incisors fused with supernumerary teeth. A severe esthetic problem and crowding in the maxillary arch were present clinically. Radiographic examination demonstrated two separate crowns, roots and pulpal canals on each side. The therapy was initiated with endodontic treatment. Six months after the completion of endodontic therapy, mesio‐distal trimming was performed and the defects were restored with anterior resin composites in order to re‐establish the esthetics. Orthodontic treatment was performed for the alignment of the upper arch. Follow‐up at 4 years demonstrated that the teeth were asymptomatic and neither root nor alveolar bone resorption was found. In conclusion, instead of extracting the supernumerary teeth, the anomaly was treated successfully in a conservative way.
Plasma homocysteine but not MTHFR gene polymorphism is associated with geriatric depression in the Chinese population
Authors: Yuan Yong-Gui , Zhang Zhi-Jun , Li Jing-Jing
Published: June 2008

Background:

Epidemiological studies suggested that elevated plasma homocysteine (Hcy) is associated with an increased risk of depression and cerebrovascular disease (CVD). There were few published reports of Hcy levels and methylenetetrahydrofolate reductase (MTHFR) C677T genotype in geriatric depression.

Objective:

To investigate the relationship among plasma Hcy level, MTHFR C677T polymorphism and geriatric depression in the Chinese population.

Methods:

The plasma Hcy level measured by capillary electrophoresis with ultraviolet detection and the C667T polymorphism of MTHFR detected using polymerase chain reaction-restriction fragment length polymorphism assay were determined in 116 patients with geriatric depression and in 80 healthy controls.

Results:

The plasma Hcy level in the patients with geriatric depression was significantly higher than that in controls (p < 0.001). The age of first episode and comorbid CVD were significantly correlated with plasma Hcy levels in geriatric patients (p = 0.014 and 0.008, respectively). The Hamilton Rating Scale for Depression total score and plasma Hcy level at baseline showed no significant correlation in the patients (r = −0.111, p = 0.397). There were no significant differences in the MTHFR C677T polymorphism genotypes and alleles between the patients and the healthy controls (p = 0.654 and 0.573, respectively).

Conclusion:

The elevated plasma Hcy level is a risk factor for geriatric depression. MTHFR C667T genotype is not associated with geriatric depression in the Chinese population.
Skin diseases in intensive care medicine
Authors: Fischer Matthias , William Thomas , Wohlrab Johannes
Published: June 2008

Though most dermatoses are not life‐threatening, skin diseases play an important role in intensive care medicine. Skin findings in intensive care patients may reflect the underlying disease or be complications of intensive medical care. Most important are drug reactions, infections, bacterial toxin reactions, erythro‐derma, ANCA‐positive vasculitides (such as Wegener granulomatosis) and bleeding disorders.
The Chronology of Depression and Distress in Men with Peyronie's Disease
Authors: Nelson Christian J. , Diblasio Chris , Kendirci Muammer , Hellstrom Wayne , Guhring Patricia , Mulhall John P.
Published: June 2008

Introduction

For the practicing clinician, appreciating Peyronie's disease (PD) significant negative psychological impact is apparent. Despite this, there exists not a single study using validated instruments assessing this issue.

Aims

To document the effect of PD on the psychosocial status of men.

Main Outcome Measures

The Center for Epidemiological Studies Depression scale (CES-D) for evaluation of depression and the SF-36 for quality of life assessment.

Methods

Men (N = 92; 54 ± 11 years of age) presenting for PD evaluation completed the CES-D, Short Form-36 (SF-36), and an inventory regarding PD. Partners were not assessed.

Results

A vast majority of men (88%) had a partner with a mean partner age of 49 ± 11 years. The median duration of PD at presentation was 12 (1–360) months. As a whole, 48% were classified as depressed on the CES-D (26% moderate, 21% severe). These subjects were then placed into groups according to the length of time since diagnosis of PD. Length-of-time groups were: 0–6 months, 6–12 months, 12–18 months, and >18 months. The percent of men scoring above the CES-D cutoff for depression remained consistently high with no significant difference across time since diagnosis groups. These results are supported by data from the Mental Health subscale (MHS) of the SF-36 (lower scores indicate lower mental heath). For the entire sample, the MHS standardized mean of 46.80 was significantly lower (P < 0.05) than the general male population standardized mean of 50. The MHS means stayed consistently low (no statistical difference) across time since diagnosis groups.

Conclusion

Using validated instruments, we have demonstrated that 48% of men with PD have clinically meaningful depression that would warrant medical evaluation. This high level of depression stayed consistent across time since diagnosis. These data suggest that most men do not psychologically adjust to their diagnosis of PD and all men with PD should be considered appropriate mental health screening.
Accuracy and effectiveness in appraisal outcomes: the influence of self‐efficacy, personal factors and organisational variables
Authors: Wood Robert E. , Marshall Verena
Published: June 2008

Two studies tested relationships of personal factors and organisational context variables with rating accuracy and perceived effectiveness of appraisals, and the role of self‐efficacy as a mediator of the relationships between the two sets of variables. Study 1 was a controlled experiment in which nurse supervisors appraised a video stimulus of a nurse's performance. Study 2 was a field study in which nurses and their supervisors each independently completed an assessment of their annual appraisal review, following the meeting. A ten‐item scale for performance appraiser self‐efficacy (PASE) was developed and tested for measurement properties on a large sample of nurses that included those who participated in either Study 1 or Study 2. The PASE scale was found to have high reliability and reasonable predictive validity. PASE predicted rating accuracy, appraiser and appraisee perceptions of effectiveness, and appraiser‐appraisee agreement on the effectiveness of an actual appraisal, after controlling for the effects of personal factors and organisational context. The main contextual influences were accountability, importance and management concern but the effects varied for self‐efficacy and different appraisal outcomes. The main predictor of self‐efficacy was the amount of training received by appraisers across the multiple sub‐tasks of appraisal.
Tuberous sclerosis with oral fibromatosis: a case report
Authors: Curi M. , Cossolin G. , Koga D. , Silva M. , Zardetto C.
Published: June 2008

Tuberous sclerosis is an autosomal dominant neurocutaneous syndrome, which may involve multiple organ systems and shows highly variable clinical manifestations. Oral manifestations, including lesions on hard tissues, enamel hypoplasia and gingival hyperplasia have been previously described. We report a case of a 25‐year‐old woman with this syndrome presenting multiple fibrous nodules on the buccal mucosa and lips. Awareness of the different oral manifestations of tuberous sclerosis is important to ensure appropriate diagnosis and treatment.
Mandibular canine transmigration: aethio‐pathogenetic aspects and six new reported cases
Authors: Pippi R. , Kaitsas R.
Published: June 2008

Mandibular canine transmigration is a rare dental ectopia that creates surgical, orthodontic, restorative and interceptive problems. Aethiologic and pathogenetic aspects of mandibular canine transmigration are examined through an international literature review.

Six new cases are then presented. All of them involve the left canine in women aged between 7 and 32 years.

Finally, a pathogenetic theory is elaborated to explain such long and lasting tooth migration. Two main factors contribute to this movement: a pericoronal osteolitic area and a strong and lasting ‘vis a tergo’ because of the root formation.

An early interceptive treatment of mandibular canine migration can avoid tooth extraction as well as complex orthodontic and restorative therapies.
A case of obstructive sleep apnea syndrome: unusual comorbidity
Authors: Jalladeau E. , Crestani B. , Laissy J.‐P. , Vecchierini M. F.
Published: June 2008

Introduction:  Launois‐Bensaude syndrome (LBS) is a rare disease, characterized by the accumulation of fatty tissue predominantly in the neck, shoulders and thorax, whose diagnostic is clinical.

Objectives:  We describe a new case in a 73 year‐old man. As the patient was obese, complained of snoring and was treated for hypertension, we looked for a morbid association with an obstructive sleep apnea syndrome (OSAS).

Methods:  A polysomnography (PSG) and a cervical magnetic resonance imaging (MRI) were performed.

Results:  PSG demonstrated OSAS with an apnea‐hypopnea index of 43/h. Cervical MRI showed fatty infiltration resulting in airway narrowing at the pharyngeal but not at the tracheal level. Only, 3 cases of such a morbid association have already been published; in 2 of these patients was a tracheal compression. More over a metabolic syndrome was present.

Conclusions:  This observation draws attention to the need for seeking OSAS among patients affected by LBS, even in a moderate form, and emphasises the roles of the upper airway narrowing by the fat infiltration as well as the role of the metabolic syndrome in the genesis of OSAS.

Please cite this paper as: Jalladeau E, Crestani B, Laissy J‐P and Vecchierini MF. A case of obstructive sleep apnea syndrome: unusual comorbidity. The Clinical Respiratory Journal 2008; 2: 239–241.
Promotion of Rural Health: Experience of an Indian NGO
Authors: Nanjunda D. C.
Published: June 2008

Promotion of rural health has become a major agenda of policy makers. Health can be more properly viewed as an index of human adaptation to a micro ecological niche. From this point of view, health management can mean the full visualization of the minimal requirements of clinical–curative inputs in health planning and management. A variety of factors have promoted increasing interest in prevention as a health care practice in the country. Numerous non‐government organizations (NGOs) are working to improve the health quality of rural India. In describing a rural health promotion project, in which a social worker played a key role, this article illustrates how social work practitioners can bring their many skills to bear in efforts to promote health. In this paper an effort has been made to share the experience of an NGO in health related project.
Is the Mongolian Health Sector Ready for a Sector‐Wide Approach?
Authors: Ulikpan Anar , Mirzoev Tolib N. , Narula Indermohan S.
Published: June 2008

Mongolia has experienced major social and economic changes since the early 1990s. Large‐scale reforms have been introduced in all sectors over the last 10 years. Implementing health reforms requires a more coordinated approach and the Mongolian health sector has been exploring an option of implementing a Sector‐Wide Approach (SWAp) to the health sector. This article aims to develop and apply an analytical framework for assessing the feasibility of implementing SWAp in the Mongolian health sector. Review of published and unpublished evidence at the national and international levels is undertaken and complemented by semi‐structured interviews with key respondents from Mongolian Ministry of Health. A framework for assessing the feasibility of SWAp in Mongolia has been developed which comprises the key elements and stages of development of SWAp in a particular context. This framework has been then applied to assess the feasibility of implementing SWAp in the Mongolian health sector. The main SWAp elements are in place. Emerging central level capacity, increasing donor confidence and willingness to move towards sector‐wide management is now becoming more evident in Mongolia. It looks like Mongolia is ready for a national level government‐led SWAp with the potential to implement a fully‐fledged SWAp in the health sector. The essential ground‐work for starting a SWAp is in place, but further capacity strengthening is needed. A framework for implementing health SWAp in Mongolia is suggested. It is important to consider the improvement of existing government systems in future SWAp arrangements to ensure local ownership.
Right atrial stretch alters fore‐ and hind‐brain expression of c‐fos and inhibits the rapid onset of salt appetite
Authors: De Gobbi Juliana Irani Fratucci , Menani Jose Vanderlei , Beltz Terry G. , Johnson Ralph F. , Thunhorst Robert L. , Johnson Alan Kim
Published: June 2008

The inflation of an intravascular balloon positioned at the superior vena cava and right atrial junction (SVC‐RAJ) reduces sodium or water intake induced by various experimental procedures (e.g. sodium depletion; hypovolaemia). In the present study we investigated if the stretch induced by a balloon at this site inhibits a rapid onset salt appetite, and if this procedure modifies the pattern of immunohistochemical labelling for Fos protein (Fos‐ir) in the brain. Male Sprague–Dawley rats with SVC‐RAJ balloons received a combined treatment of furosemide (Furo; 10 mg (kg bw)−1) plus a low dose of the angiotensin‐converting enzyme inhibitor captopril (Cap; 5 mg (kg bw)−1). Balloon inflation greatly decreased the intake of 0.3 m NaCl for as long as the balloon was inflated. Balloon inflation over a 3 h period following Furo–Cap treatment decreased Fos‐ir in the organum vasculosum of the lamina terminalis and the subfornical organ and increased Fos‐ir in the lateral parabrachial nucleus and caudal ventrolateral medulla. The effect of balloon inflation was specific for sodium intake because it did not affect the drinking of diluted sweetened condensed milk. Balloon inflation and deflation also did not acutely change mean arterial pressure. These results suggest that activity in forebrain circumventricular organs and in hindbrain putative body fluid/cardiovascular regulatory regions is affected by loading low pressure mechanoreceptors at the SVC‐RAJ, a manipulation that also attenuates salt appetite.
Differential effects of resistance and endurance exercise in the fed state on signalling molecule phosphorylation and protein synthesis in human muscle
Authors: Wilkinson Sarah B. , Phillips Stuart M. , Atherton Philip J. , Patel Rekha , Yarasheski Kevin E. , Tarnopolsky Mark A. , Rennie Michael J.
Published: June 2008

Resistance (RE) and endurance (EE) exercise stimulate mixed skeletal muscle protein synthesis. The phenotypes induced by RE (myofibrillar protein accretion) and EE (mitochondrial expansion) training must result from differential stimulation of myofibrillar and mitochondrial protein synthesis. We measured the synthetic rates of myofibrillar and mitochondrial proteins and the activation of signalling proteins (Akt–mTOR–p70S6K) at rest and after an acute bout of RE or EE in the untrained state and after 10 weeks of RE or EE training in young healthy men. While untrained, RE stimulated both myofibrillar and mitochondrial protein synthesis, 67% and 69% (P < 0.02), respectively. After training, only myofibrillar protein synthesis increased with RE (36%, P= 0.05). EE stimulated mitochondrial protein synthesis in both the untrained, 154%, and trained, 105% (both P < 0.05), but not myofibrillar protein synthesis. Acute RE and EE increased the phosphorylation of proteins in the Akt–mTOR–p70S6K pathway with comparatively minor differences between two exercise stimuli. Phosphorylation of Akt–mTOR–p70S6K proteins was increased after 10 weeks of RE training but not by EE training. Chronic RE or EE training modifies the protein synthetic response of functional protein fractions, with a shift toward exercise phenotype‐specific responses, without an obvious explanatory change in the phosphorylation of regulatory signalling pathway proteins.
Developmental reprogramming of rat GLUT5 requires glucocorticoid receptor translocation to the nucleus
Authors: Douard Véronique , Choi Hye‐In , Elshenawy Summer , Lagunoff David , Ferraris Ronaldo P.
Published: June 2008

Fructose consumption has increased dramatically but little is known about mechanisms regulating the intestinal fructose transporter GLUT5 in vivo. In neonatal rats, GLUT5 can be induced only by luminal fructose and only after 14 days of age, unless the gut is primed with dexamethasone prior to fructose perfusion. To elucidate the mechanisms underlying dexamethasone modulation of GLUT5 development, we first identified the receptor mediating its effects then determined whether those effects were genomic. The glucocorticoid receptor (GR) antagonist RU486 dose‐dependently prevented the dexamethasone‐mediated effects on body weight, intestinal arginase2 (a known GR‐regulated gene) and GLUT5. In contrast, an antagonist of the mineralocorticoid receptor as well as agonists of progesterone (PR) and pregnane‐X (PXR) receptors did not block the effects of dexamethasone. These receptor antagonists and agonists had no effect on the intestinal glucose transporter SGLT1. Translocation of the GR into the enterocyte nucleus occurred only in dexamethasone‐injected pups perfused with fructose, was accompanied by marked increases in brush border GLUT5 abundance, and was blocked by RU486. A priming duration of ∼24 h is optimal for induction but actinomycin D injection before dexamethasone priming prevented dexamethasone from allowing luminal fructose to induce GLUT5. Actinomycin D had no effect on dexamethasone‐independent fructose‐induced increases in glucose‐6‐phosphatase mRNA abundance, suggesting that it did not prevent fructose‐induction of GLUT5, but instead prevented dexamethasone‐induced synthesis of an intermediate required by fructose for GLUT5 regulation. In suckling rats < 14 days old, developmental regulation of transporters may involve cross‐talk between hormonal signals modulating intestinal maturation and nutrient signals regulating specific transporters.
Refinement of the retinogeniculate pathway
Authors: Guido William
Published: June 2008

Much of our present understanding about the mechanisms contributing to the activity‐dependent refinement of sensory connections comes from experiments done in the retinogeniculate pathway. In recent years the mouse has emerged as a model system of study. This review outlines the major changes in connectivity that occur in this species and a potential mechanism that can account for such remodelling. During early postnatal life when spontaneous activity of retinal ganglion cells sweeps across the retina in waves, retinal projections from the two eyes to the dorsal lateral geniculate nucleus (LGN) segregate to form non‐overlapping eye‐specific domains. There is a loss of binocular innervation, a pruning of excitatory inputs from a dozen or more to one or two, and the emergence of inhibitory circuitry. Many of these changes underlie the development of precise eye‐specific visual maps and receptive field structure of LGN neurons. Retinal activity plays a major role both in the induction and maintenance of this refinement. The activity‐dependent influx of Ca2+ through L‐type channels and associated activation of CREB signalling may underlie the pruning and stabilization of developing retinogeniculate connections.
Infrared Radiative Properties of Submicron Metallic Slit Arrays
Authors: Chen Y.-B. , Lee B. J. , Zhang Z. M.
Published: June 2008

Submicron metallic slit arrays with different geometry were designed and fabricated on silicon substrates. Their infrared radiative properties (transmittance, reflectance, and absorptance) were investigated both experimentally and theoretically. The normal transmittance of three fabricated Au slit arrays was measured at wavelengths between 2μm and 15μm using a Fourier-transform infrared spectrometer. The experimental results were compared to the values calculated from the rigorous coupled-wave analysis. The applicability of the effective medium theory for modeling radiative properties was also examined. The agreement between the measurement and modeling results demonstrates the feasibility of quantitative tuning of the radiative properties by employing periodic micro/nanostructures.
A Hierarchical Statistical Sensitivity Analysis Method for Complex Engineering Systems Design
Authors: Yin Xiaolei , Chen Wei
Published: June 2008

Statistical sensitivity analysis (SSA) is playing an increasingly important role in engineering design, especially with the consideration of uncertainty. However, it is not straightforward to apply SSA to the design of complex engineering systems due to both computational and organizational difficulties. In this paper, to facilitate the application of SSA to the design of complex systems especially those that follow hierarchical modeling structures, a hierarchical statistical sensitivity analysis (HSSA) method containing a top-down strategy for SSA and an aggregation approach to evaluating the global statistical sensitivity index (GSSI) is developed. The top-down strategy for HSSA is introduced to invoke the SSA of the critical submodels based on the significance of submodel performances. A simplified formulation of the GSSI is studied to represent the effect of a lower-level submodel input on a higher-level model response by aggregating the submodel SSA results across intermediate levels. A sufficient condition under which the simplified formulation provides an accurate solution is derived. To improve the accuracy of the GSSI formulation for a general situation, a modified formulation is proposed by including an adjustment coefficient (AC) to capture the impact of the nonlinearities of the upper-level models. To improve the efficiency, the same set of samples used in submodel SSAs is used to evaluate the AC. The proposed HSSA method is examined through mathematical examples and a three-level hierarchical model used in vehicle suspension systems design.
Design and Analysis of a Hybrid Mobile Robot Mechanism With Compounded Locomotion and Manipulation Capability
Authors: Ben-Tzvi Pinhas , Goldenberg Andrew A. , Zu Jean W.
Published: June 2008

This paper presents a novel design paradigm as well as the related detailed mechanical design embodiment of a mechanically hybrid mobile robot. The robot is composed of a combination of parallel and serially connected links resulting in a hybrid mechanism that consists of a mobile robot platform for locomotion and a manipulator arm for manipulation. Unlike most other mobile robot designs that have a separate manipulator arm module attached on top of the mobile platform, this design has the ability to simultaneously and interchangeably provide locomotion and manipulation capability. This robot enhanced functionality is complemented by an interchangeable track tension and suspension mechanism that is embedded in some of the mobile robot links to form the locomotion subsystem of the robot. The mechanical design was analyzed with a virtual prototype that was developed with MSC ADAMS software. The simulation was used to study the robot’s enhanced mobility characteristics through animations of different possible tasks that require various locomotion and manipulation capabilities. The design was optimized by defining suitable and optimal operating parameters including weight optimization and proper component selection. Moreover, the simulation enabled us to define motor torque requirements and maximize end-effector payload capacity for different robot configurations. Visualization of the mobile robot on different types of virtual terrains such as flat roads, obstacles, stairs, ditches, and ramps has helped in determining the mobile robot’s performance, and final generation of specifications for manufacturing a full scale prototype.
Nonlinear Effects on Wave Groups in Random Seas
Authors: Kriebel D. L. , Dawson T. H.
Published: June 2008

Laboratory simulations of extreme random seas reveal that high wave crests occur more frequently than predicted by the Rayleigh distribution. In this paper, a theory is presented to account for nonlinearities in the sea state to second order resulting in a non-Rayleigh distribution of wave crest and trough amplitudes based on the narrow-band assumption. The resulting probability density functions are then used to predict average wave group characteristics through a modification of linear wave envelope theory which accounts, for example, for a significant decrease in the time intervals between successive runs of high crests compared to linear theory. The nonlinear theory is then verified based on a laboratory data set on deep water wave group statistics for severe seas described by Bretschneider and JONSWAP spectra.
Stochastic Response of a Tension Leg Platform to Viscous Drift Forces
Authors: Donley M. G. , Spanos P. D.
Published: June 2008

A stochastic analysis of a tension leg platform subjected to wave and current loads is performed. The viscous force is modeled by the nonlinear Morison equation drag force term. As an improvement to equivalent stochastic linearization of the drag force, an equivalent stochastic “quadratization” method is proposed, in which the drag force nonlinearity is replaced by an “equivalent” quadratic nonlinearity. The resulting nonlinear equivalent system is in a form which can be solved approximately by a Volterra series expansion. The non-Gaussian probability distribution of the response is approximated by a Gram-Charlier expansion. The method is applied on a three degree-of-freedom model. The power spectrum of the response determined by the proposed method compares well with the one obtained by a Monte-Carlo simulation.
Probabilistic Design of the Tethers of a Tension Leg Platform
Authors: Lotsberg I.
Published: June 2008

Probabilistic design of the tethers of a tension leg platform is described. It is used to determine the maximum and minimum tension in tethers for the intact condition. The reliability of the tethers for maximum and minimum tension when one tether is missing has been calculated. Also, the reliability of maximum and minimum tension in the tethers as a function of flooding of a corner column has been calculated.
Large-Amplitude Oscillations of Geometrically Nonlinear Elastic Beams Subjected to Hydrodynamic Excitation
Authors: Bruschi R. , Vitali L.
Published: June 2008

The dynamic response of slender pipes to cyclic flexural excitations could be significantly influenced by the “membrane” stiffness of a beam axially restrained at the ends, where the magnitude of the exciting force is such as to induce large lateral deflections. This typical nonlinearity of structural mechanics is generally approached adopting semi-analytical procedures for simple configurations, and more often using numerical solutions as well as finite element techniques for more realistic configurations. This paper deals with: the mathematical formulation of large-amplitude oscillations of geometrically nonlinear beams; and numerical models for nonlinear response of beams under harmonic and random excitations. Two applications are reported: analysis of the effect of the initially deflected shape on dynamic response under regular vortex shedding; analysis of the dynamic stiffening due to axial restraint on lock-in range.
Fundamental Prediction of Steel Weld Metal Properties
Authors: Ibarra S. , Olson D. L. , Liu S.
Published: June 2008

Empirically derived expressions are commonly used to predict specific steel weldment properties. These expressions usually consider only constitutional considerations and are limited to their ability to predict the influence of the thermal experience (heat input, weld preparation, and plate thickness). Carbon equivalent and basicity index are examples of such predictive expressions. This paper reviews some of the existing expressional forms and introduces new functional forms that are based on metallurgical engineering concepts. Forms for equations which can predict weld metal properties and behavior as a function of composition are proposed. Methodology for including cooling rate in the predictive equations is also suggested. The concept of developing iso-property diagrams that allow better selection of welding consumables with variations in heat input is introduced and discussed.
Confined Compressive Strength of Horizontal First-Year Sea Ice Samples
Authors: Richter-Menge J. A.
Published: June 2008

A total of 110 first-year sea ice samples from Prudhoe Bay, Alaska, were tested in unconfined and confined constant strain rate compression. All of the tests were performed in the laboratory on a closed-loop electrohydraulic testing machine at −10°C. The confined tests were performed in a conventional triaxial cell (σ1>σ2=σ3) that maintained a constant ratio between the radial and axial stress (σ2/(σ1)=constant) to simulate true loading conditions. Three strain rates (10−2, 10−3, and 10−5/s) and three σ2/σ1 ratios (0.25, 0.50, and 0.75) were investigated. This paper summarizes the field sampling and testing techniques and presents data on the effect of confinement on the compressive strength, initial tangent modulus, and failure strain of the ice.
Variable Physical Properties in Natural Convective Gas Microflow
Authors: Weng Huei Chu , Chen Cha’o-Kuang
Published: June 2008

Anisothermal flow prevails in a heated microchannel. It is desirable to understand the influence of temperature-dependent physical properties on the flow and heat transfer characteristics for natural convective gas microflow. In this study, formulas for the shear viscosity, thermal conductivity, constant-pressure specific heat, density, and molecular mean free path are proposed in power-law form and validated through experimental data. Natural convective gas flow with variable physical properties in a long open-ended vertical parallel-plate microchannel with asymmetric wall temperature distributions is further investigated. The full Navier–Stokes equations and energy equation combined with the first-order slip∕jump boundary conditions are employed. Analysis process shows that the compressibility and viscous dissipation terms in balance equations are negligible. Numerical solutions are presented for air at the standard reference state with complete accommodation. It is found that the effect of variable properties should be considered for hotter-wall temperatures greater than 306.88K. The effect is to advance the velocity slip and temperature jump as well as the velocity symmetry and temperature nonlinearity. Moreover, it tends to reduce the mass flow rate and the local heat transfer rate excluding on the cooler-wall surface where the temperature-jump effect prevails over the temperature-nonlinearity effect. Increasing the cooler-wall temperature magnifies the effect on flow behavior but minifies that on thermal behavior.
Experimental Investigation of Performance of a Residential Air Conditioning System with an Evaporatively Cooled Condenser
Authors: Goswami D. Y. , Mathur G. D. , Kulkarni S. M.
Published: June 2008

This paper presents an experimental investigation of the use of indirect evaporative cooling process to increase the performance of an air-to-air vapor compression refrigeration system. The condenser of an existing 2.5 ton (8.8 kW) air conditioning system at the University of Florida’s Energy Park in Gainesville was retrofitted with a media pad type evaporative cooler, a water source, and a pump. The system performance was monitored without and with the evaporative cooler on the condenser. The data show that electric energy savings of 20 percent can be achieved by using an evaporatively cooled air condenser. The energy savings can pay for the cost associated with retrofitting the condenser in as little as two years.
Desiccant Degradation in Desiccant Cooling Systems: An Experimental Study
Authors: Pesaran A. A.
Published: June 2008

We conducted experiments to quantify the effects of thermal cycling and exposure to contamination on solid desiccant materials that may be used in desiccant cooling systems. The source of contamination was cigarette smoke, which is considered one of the worst pollutants in building cooling applications. We exposed five different solid desiccants to “ambient” and “contaminated” humid air: silica gel, activated alumina, activated carbon, molecular sieves, and lithium chloride. We obtained the moisture capacity of samples as a function of exposure time. Compared to virgin desiccant samples, the capacity loss caused by thermal cycling with humid ambient air was 10 percent to 30 percent for all desiccants. The capacity loss because of combined effect of thermal cycling with “smoke-filled” humid air was between 30 percent to 70 percent. The higher losses occurred after four months of experiment time, which is equivalent to four to eight years of field operation. Using a system model and smoke degradation data on silica gel, we predicted that, for low-temperature regeneration, the loss in performance of a ventilation-cycle desiccant cooling system would be between 10 percent to 35 percent, in about eight years, with higher value under worst conditions.
Turbulence Measured by Anemometers, Kites and Turbine Blade Strain
Authors: Daniels P. A.
Published: June 2008

Anemometer and strain guaged Tala kite wind data are analyzed with concurrent blade strain on a 600 kW wind turbine. While anemometer spectra drop at 1 Hz, the kite shows considerable energy up to several Hz. The rain flow count method identified discrete and nested cycles in the data. When registering a large amplitude cycle, the kite moved significantly from it’s no cycle position demonstrating that the kite actively seeks out and samples turbulence lumps over an area as opposed to a fixed anemometer. The kite simulated measured number of cycles and durations reasonably well while the anemometer failed.
Desiccant Degradation in Desiccant Cooling Systems: A System Study
Authors: Pesaran A. A.
Published: June 2008

We predicted the impact of desiccant degradation on the performance of an open-cycle desiccant cooling system in ventilation mode using the degradation data on silica gel obtained from a previous study. The degradation data were based on thermal cycling desiccant samples and exposing them to ambient or contaminated air. Depending on the degree of desiccant degradation, the decrease in the thermal coefficient of performance (COP) and the cooling capacity of the system for low-temperature regeneration was 10 percent to 35 percent. The 35 percent loss occurred based on the worst-case desiccant degradation scenario. Under more realistic conditions the loss in system performance is expected to be lower.
Performance of Nonconcentrating Solar Photocatalytic Oxidation Reactors: Part I—Flat-Plate Configuration
Authors: Wyness P. , Klausner J. F. , Goswami D. Y. , Schanze K. S.
Published: June 2008

A nonconcentrating flat-plate photoreactor has been fabricated and tested in an outdoor solar photocatalytic oxidation facility. It has been demonstrated that 4-chlorophenol (4CP) is successfully oxidized when operating under either sunny or cloudy atmospheric conditions. Tests have been conducted with the photocatalyst, titanium dioxide (TiO2), either mixed into the 4CP solution to form a slurry or adhered to a fiberglass mesh in a fixed configuration. The reaction rate constant for the slurry mode is typically two to five times greater than that for the fixed catalyst mesh tested at similar ultraviolet (UV) insolation conditions. In addition, the reaction rate constant appears to vary linearly with the UV insolation, and it shows no dependence on liquid film thickness in the slurry mode, but appears to vary linearly with the inverse of film thickness in the fixed catalyst mode. All tests were performed in the laminar flow regime. Design recommendations for industrial development are presented.
Optical Performance of Conical Windows for Concentrated Solar Radiation
Authors: Kribus A.
Published: June 2008

Radiative energy transfer through a truncated cone window with a back-plane reflector is considered. This geometry is proposed for a high-pressure direct-radiation (volumetric) central solar receiver for use in combined-cycle electricity generation. The transmission and loss characteristics, computed by ray-tracing, are parameterized by the angle of incident radiation relative to the cone axis. The overall performance of the window is an integral of the angle-dependent transmission data, weighted by the actual distribution of input radiation, over all incidence angles. This parameterization provides insight and assists in tailoring of the window geometry to different solar collection methods. Results are presented for several window geometries. Overall window performance is presented for a dish-type distribution of input radiation.
Optimization of Parabolic Trough Collector Design for Varying Manufacturing Tolerances Using a Closed-Form Expression for Intercept Factor
Authors: Gu¨ven H. M.
Published: June 2008

In this paper, a closed-form expression for intercept factor is used to carry out the optimization of parabolic trough collector geometry (rim angle and concentration ratio). It is shown that the presented closed-form expression eliminates the need for a detailed ray-trace computer code and facilitates optimization of the collector optical design parameters.
Multiobjective Optimal Unit Sizing of Hybrid Power Generation Systems Utilizing Photovoltaic and Wind Energy
Authors: Yokoyama Ryohei , Ito Koichi , Yuasa Yoshiro
Published: June 2008

A deterministic approach to optimal unit sizing is presented for hybrid power generation systems utilizing photovoltaic and wind energy. Device capacities and electric contract demand are determined so as to minimize the annual total cost and annual energy consumption from the viewpoints of economy and energy saving or reduction in NOx and CO2 emission, respectively. This optimization problem is considered as a multiobjective one, and a discrete set of Pareto optimal solutions is derived numerically by using the weighting method. Two systems interconnected with the electric power grid are investigated: one has the option of reverse electricity flow into the grid, and the other has no option. By carrying out some case studies, the tradeoff relationships between the two objectives as well as the optimal values of device capacities are clarified. The influence of electricity deficit on unit sizing is also investigated.
A Model for the Determination of Residual Fatigue Life of a Nickel-Based Superalloy
Authors: Ye Duyi , Zheng Jinyang
Published: June 2008

In this paper, both the dissipation of the plastic-strain energy and the exhaustion of the static toughness during high-temperature low-cycle fatigue of GH4145/SQ superalloy were investigated. Together with the analysis of the microscopic aspects of the material, an energy-based damage mechanics model was developed for the prediction of the residual fatigue life of the high-temperature fastened parts in power plant. Experimental results show that the static toughness is a parameter that is highly sensitive to the fatigue damage process. The deterioration of the static toughness during fatigue process reveals the exhaustion of the materials’s ability to absorb energy, which is essentially associated with the irreversible energy dissipation process of the fatigue failure. Based on the dissipation of the plastic-strain energy and the exhaustion of the static toughness during fatigue, a damage variable is defined that is consistent with the fatigue damage mechanism. The variable is sensitive to the fatigue process and can be measured with a simple experimental procedure. A fatigue damage evolution equation is derived on the basis of Lemaitre’s potential of dissipation in the framework of continuum damage mechanics. Furthermore, an equation for the determination of the residual fatigue life is deduced. The fatigue damage mechanics model is verified by comparing the predicted results with the experimental observations. The fatigue damage mechanics model developed may provide a feasible approach to determining the residual fatigue life of the high-temperature fastened parts in power plant.
Parametric Finite-Volume Micromechanics of Uniaxial Continuously-Reinforced Periodic Materials With Elastic Phases
Authors: Gattu Mahendra , Khatam Hamed , Drago Anthony S. , Pindera Marek-Jerzy
Published: June 2008

The finite-volume direct averaging micromechanics (FVDAM) theory for periodic heterogeneous materials is extended by incorporating parametric mapping into the theory’s analytical framework. The parametric mapping enables modeling of heterogeneous microstructures using quadrilateral subvolume discretization, in contrast with the standard version based on rectangular subdomains. Thus arbitrarily shaped inclusions or porosities can be efficiently rendered without the artificially induced stress concentrations at fiber/matrix interfaces caused by staircase approximations of curved boundaries. Relatively coarse unit cell discretizations yield effective moduli with comparable accuracy of the finite-element method. The local stress fields require greater, but not exceedingly fine, unit cell refinement to generate results comparable with exact elasticity solutions. The FVDAM theory’s parametric formulation produces a paradigm shift in the continuing evolution of this approach, enabling high-resolution simulation of local fields with much greater efficiency and confidence than the standard theory.