bluuebunny/crossref_metadata_2025 huggingface dataset:
Suture adjustment in penetrating keratoplasty
Authors: Høvding Gunnar
Published: May 2009

Abstract Postoperative adjustment of a single running penetrating corneal graft suture was done in 19 patients (22 adjustments). The short‐term effect of this procedure was a mean reduction of corneal astigmatism of 4.39D (p < 0.0001). Thereafter, the corneal contour was fairly stable, provided that the running suture remained intact and tight. Localized loosening of the graft suture significantly increased the corneal astigmatism. Following removal of the graft suture no statistically significant mean change of corneal astigmatism was found. However, patients with a previously intact running suture tended to show increased astigmatism, while those with a previous localized suture loosening usually showed a decreased astigmatism after suture removal. The main benefit of suture adjustment is apparantly the rapid and fairly stable reduction of postkeratoplasty astigmatism usually obtained, but unfortunately this effect seems chiefly to exist only as long as the graft suture remains intact and tight.
Progressive subretinal fibrosis in fundus flavimaculatus
Authors: Parodi Maurizio Battaglia
Published: May 2009

Abstract Fundus flavimaculatus is a peculiar bilateral retinal dystrophy with yellow‐white flecks at the level of the retinal pigment epithelium. During a 9‐year follow‐up we observed the occurrence of an increasing number of chorioretinal punched‐out spots in the posterior pole and midperiphery, with progressive development of subretinal fibrosis, in a young female patient. The possible etiopathogenetic aspects are discussed.
Herpes simplex virus in chronic relapsing keratoconjunctivitis
Authors: Tabery Helena M.
Published: May 2009

Abstract In a patient with a 5‐month history of chronic relapsing keratoconjunctivitis, herpes simplex virus antigen was disclosed by immunoflurescence test in material obtained by conjunctival scraping, and the symptoms resolved following acyclovir (Zovirax) treatment. The diagnostic difficulties with patients presenting without symptoms suggestive of herpes simplex virus may be responsible for the lack of similar reports.
Diffuse chronic retinal pigment epitheliopathy and exudative retinal detachment
Authors: Laatikainen Leila
Published: May 2009

Abstract Two patients with bilateral chronic retinal pigment epitheliopathy are presented. Both patients had large areas of pigment epithelial decompensation and small pigment epithelial detachments at the posterior pole. In the macula subretinal fluid was scanty, but the first patient developed an extensive bullous retinal detachment with shifting of subretinal fluid with changes in posture in both eyes, the second patient had similar detachment in one eye. The etiology of the pigment epithelial disorder remained unknown. No inflammatory cells were found in the vitreous specimen or subretinal fluid in the first patient. Treatment with peroral corticosteroids alone or in combination with azathioprine and cyclosporin A, as well as surgery for retinal detachment in one eye, proved unsuccessful. Argon laser coagulation of the decompensated areas in the macula resulted in resorption of subretinal fluid and reattachment of the exudative detachment.
Visual fields at different stages of diabetic retinopathy
Authors: Henricsson Marianne , Heijl Anders
Published: May 2009

Abstract Available studies on visual field disturbances in diabetic retinopathy have shown conflicting results, obtained with different and often non‐comparable techniques. We have studied visual fields at different stages of diabetic retinopathy with modern sensitive computerized technique taking precautions to limit disturbing effects of random field variation and lack of perimetric experience. Sixty‐three diabetic patients, insulin‐dependent and non‐insulin dependent, were each subject to three test sessions using the 30‐2 full threshold program of the Humphrey perimeter. Retinopathy levels ranged from 10 to 65 in the ETDRS Final scale. In eyes without retinopathy or with very mild and mild disease (levels 10–35) mean deviation values exceeding the p < 5% level occurred in only 4% of eyes in trained sessions, and the number of test points with significantly reduced sensitivity did not exceed that expected in normal eyes. In moderate and moderately severe diabetic retinopathy (levels 43–47) and in severe non‐proliferative and proliferative retinopathy (levels 53–65) there was clear evidence of field loss, however, with significantly reduced mean deviation values in 44% of the eyes and 6.5% of tested points showing reproducible loss of sensitivity. Thus, there was no evidence of field loss in eyes with mild disease, but clear field defects in eyes with more advanced disease. Significantly reduced sensitivity was often correlated with retinal non‐perfusion and there was seen a tendency towards more correlation in the midperiphery than paracentrally.
Binocular inhibition of visual performance in patients with cataract
Authors: McElvanney Andrena , Moseley Merrick J. , Jones Helen S.
Published: May 2009

Abstract Patients with cataract may show binocular inhibition: their sight improves on closing the eye in which vision is poorer. Of 36 patients questioned, one‐third reported this to be the case. To quantify this phenomenon, all patients undertook a battery of tests of spatial visual performance and, in an attempt to define the reliability of their scores, were tested on two separate occasions. Patients generally performed inconsistently: at best, of 8 patients who demonstrated inhibition on a single test, only 5 did so again when re‐tested after a short interval. In general, the magnitude of inhibition was less than that which could be reliably detected using the test battery. In addition, self‐reported inhibition was not predictive of inhibition measured psychophysically. It is concluded that clinical tests of form vision lack either the necessary reliability or sensitivity to identify patients with cataract who report inhibition of binocular visual function.
Long‐term natural and modified course of surgically induced astigmatism after extracapsular cataract extraction
Authors: Storr‐Paulsen Allan , Vangsted Peter , Perriard Andreas
Published: May 2009

Abstract A prospective study was carried out to investigate the long‐term course of surgically induced astigmatism after extracapsular cataract extraction. Sixty‐one eyes were followed for 36 months. In 27 eyes with postoperative astigmatism > 4D widi‐the‐rule, one or two sutures were cut in the steeper meridian after 3 months. In another group of 34 eyes with only minor or no postoperative astigmatism with‐the‐rule, no suture was cut. We found that 1) postoperative astigmatism was significantly increased in all eyes after 1 week and 3 months, but decreased in time approaching preoperative values after 3 years, 2) surgically induced astigmatism was with‐the‐rule at 1 week and 3 months but turned against‐the‐rule in rime in both groups. Astigmatism decay rate was significantly steeper in eyes with suture cutting, 3) the keratometric axis was exclusively with‐the‐rule after 1 week, but turned against‐the‐rule in both groups, approaching the preoperative distribution of axis after 3 years. We concluded that surgically induced astigmatism is a dynamic feature showing changes in size and axis even in the period 1–3 years postoperatively. Suture cutting seems to intensify the decrease in the induced astigmatism and accelerate the shift in astigmatic axis, turning astigmatism against‐the‐rule compared to eyes with intact sutures.
The influence of age on characteristics of cataract patients
Authors: Drolsum Liv , Haaskjold Erling
Published: May 2009

Abstract The influence of age on 12 pre‐, 1 intra‐, and 2 postoperative patients' characteristics was investigated in 1261 consecutively performed extracapsular cataract extractions. The following characteristics were shown to be significantly associated with increasing age; cardiovascular disease (p < 0.0005), female gender (p < 0.0005), nuclear sclerosis (p < 0.0005), maculopathy (p < 0.0005), corneal guttatae (p = 0.008) and reducing visual acuity in the fellow eye (p < 0.0005). Further, inadequate mydriasis at start of surgery was significantly associated with increasing age even after adjusting for glaucoma and pseudoexfoliation (p = 0.0007). After adjusting for pseudoexfoliation, a statistically significant relationship still existed between age and glaucoma (p = 0.0235). Even after controlling for relevant variables, i.e. maculopathy, a highly significant association was found between reducing visual acuity 4 months postoperatively and increasing age (p < 0.00005). Diabetes mellitus, the degree of cataract maturity, preoperative visual acuity of the operating eye, vitreous loss and postoperative inflammatory response were not significantly associated with increasing age.
The αGal HyperAcute® Technology: Enhancing Immunogenicity of Antiviral Vaccines by Exploiting the Natural αGal‐Mediated Zoonotic Blockade
Authors: Mandell R. B. , Flick R. , Staplin W. R. , Kaniewski L. D. , Carzoli A. K. , Manuszak R. P. , Wang J. , Rossi G. R. , Vahanian N. N. , Link C. J.
Published: May 2009

The αGal HyperAcute® Technology exploits a robust zoonotic blockade to enhance potency of antiviral vaccines. Naturally acquired immunity against the common αGal epitope [galactose‐alpha(1,3)‐galactose‐beta(1,4)N‐acetylglucosamine‐R (Gal‐α(1,3)‐Gal‐β(1,4)‐GlcNAc‐R)] is facilitated by the loss of a key enzyme in the epitope’s biosynthetic pathway. As human cells are devoid of this epitope, chronic stimulus from gut flora leads to high levels of circulating anti‐αGal antibodies and the development of a robust immune pathway. As the αGal epitope is immediately recognized as foreign, the naturally acquired αGal immune pathway in humans serves as a strong barrier to zoonotic infection. The αGal HyperAcute® Technology takes advantage of this natural process to facilitate the rapid presentation of modified antigens to antigen‐presenting cells, leading to a strong immune response. The evolutionary immunity to αGal ensures that the presence of αGal epitopes on antigens will lead to a robust immune response involving cross‐activation of TH1 immunity, characterized by cytokine secretion and increased phagocytic activity, and TH2 immunity characterized by high antibody titres. αGal epitopes can be applied to antiviral vaccines by biological, enzymatic or chemical means. Several detection methods that directly and indirectly verify αGal addition are discussed. Enhanced immunogenicity (humoral and cellular) of αGal‐modified vaccines is shown for several antiviral vaccine candidates. αGal modification of antiviral vaccine components leads to enhanced immunogenicity. The existing body of literature describing the utility of αGal epitopes as a safe and robust immunostimulatory and ‐modulatory agent in humans supports the basis for applying the αGal HyperAcute® Technology to the improvement of antiviral vaccines, both new and currently approved.
West Nile Virus in the New World: Trends in the Spread and Proliferation of West Nile Virus in the Western Hemisphere
Authors: Artsob H. , Gubler D. J. , Enria D. A. , Morales M. A. , Pupo M. , Bunning M. L. , Dudley J. P.
Published: May 2009

The observed patterns and variations in the ecology, epidemiology, distribution and prevalence of the West Nile Virus (WNV) in different areas of the Western Hemisphere make this pathogen of particular importance as a model for understanding the potential risk factors associated with emerging pathogens worldwide, particularly those involving zoonotic pathogens whose epidemiology involves the potential for vertical transmission in arthropod vector species, and horizontal and vertical transmission within and among vertebrate host species. Record numbers of human WNV cases were recorded in Canada during 2007, with >50% more cases than documented in any previous year. Although overall numbers of human infections recorded in the United States were not exceptionally high during 2007 relative to epidemic levels reported in 2002 and 2003, the state of Oklahoma reported that the highest‐ever number of human WNV cases and the numbers of human cases recorded in Canada were 50% higher than previous record levels recorded in 2003. The record and near‐record numbers of human WNV infections recorded in several regions of North America during 2007 have important implications for the future management and surveillance of WNV vectors and reservoirs in North America. The spatiotemporal distribution of WNV infections in humans and animals recorded during 2007 in North America and South America have important implications for the surveillance and management of public health threats from WNV in the Western Hemisphere. Serological surveys conducted in areas of intense WNV transmission in the United States have reported low prevalence of antibodies to WNV in human s populations, indicating that additional epidemic outbreaks of human disease from WNV can be expected in the future.
Genetic Diversity and Geographic Distribution of Hantaviruses in Russia
Authors: Garanina S. B. , Platonov A. E. , Zhuravlev V. I. , Murashkina A. N. , Yakimenko V. V. , Korneev A. G. , Shipulin G. A.
Published: May 2009

Haemorrhagic fever with renal syndrome (HFRS) is the most prevalent zoonotic disease in Russia. It is caused by several hantavirus species hosted by small rodents. We describe spatial and temporal patterns of HFRS incidence in the Russian Federation, and the geographic distribution of prevalent hantavirus species: Puumala (PUUV) and Dobrava (DOBV). Partial sequencing of nucleocapsid and glycoprotein genes of 117 PUUV strains and 78 DOBV strains revealed several distinct genetic subgroups. The RNA of Volga PUUV subgroup was detected in patients with HFRS and bank voles Myodes glareolus in the Volga Federal District, where the highest HFRS incidence rate has been registered yearly. The RNA of Siberian PUUV subgroup was found in M. glareolus in the trans‐Ural Tyumen and Omsk Provinces, where human HFRS cases have been rare. During an HFRS outbreak in 2007 in the Central Federal District, when more than 1000 patients were affected, specific subgroups of DOBV were discovered in patients and rodents, mainly in the striped field mouse Apodemus agrarius. DOBV strains might have 8–9% of nucleotide difference although they were collected at places separated by 30–100 km. The RNA of a unique DOBV subgroup was discovered in the southern semi‐desert Astrakhan Province, mainly in A. agrarius and tamarisk jird Meriones tamariscinus. No human HFRS cases were diagnosed in this province. Russian PUUV and DOBV strains have no close homologues among European strains. Our DOBV strains might be genetically grouped together with Central European DOBV strains isolated from A. agrarius, but not from Apodemus flavicollis. The Volga PUUV subgroup is to some extent similar to Baltic PUUV strain, and Finnish PUUV strains resemble the strains from the Siberian PUUV subgroup. Thus, PCR‐based monitoring and typing provided the opportunity to delineate and expand the area of hantaviruses in Russia and to identify their new genetic variants.
The Role of Swine in the Generation of Novel Influenza Viruses
Authors: Ma W. , Lager K. M. , Vincent A. L. , Janke B. H. , Gramer M. R. , Richt J. A.
Published: May 2009

The ecology of influenza A viruses is very complicated involving multiple host species and viral genes. Avian species have variable susceptibility to influenza A viruses with wild aquatic birds being the reservoir for this group of pathogens. Occasionally, influenza A viruses are transmitted to mammals from avian species, which can lead to the development of human pandemic strains by direct or indirect transmission to man. Because swine are also susceptible to infection with avian and human influenza viruses, genetic reassortment between these viruses and/or swine influenza viruses can occur. The potential to generate novel influenza viruses has resulted in swine being labelled ‘mixing vessels’. The mixing vessel theory is one mechanism by which unique viruses can be transmitted from an avian reservoir to man. Although swine can generate novel influenza viruses capable of infecting man, at present, it is difficult to predict which viruses, if any, will cause a human pandemic. Clearly, the ecology of influenza A viruses is dynamic and can impact human health, companion animals, as well as the health of livestock and poultry for production of valuable protein commodities. For these reasons, influenza is, and will continue to be, a serious threat to the wellbeing of mankind.
Cyclic stretch reduces myofibrillar protein synthesis despite increases in FAK and anabolic signalling in L6 cells
Authors: Atherton P. J. , Szewczyk N. J. , Selby A. , Rankin D. , Hillier K. , Smith K. , Rennie M. J. , Loughna P. T.
Published: May 2009

Muscle protein synthesis is increased after exercise, but evidence is now accruing that during muscular activity it is suppressed. In life, muscles are subjected to shortening forces due to contraction, but may also be subject to stretching forces during lengthening. It would be biologically inefficient if contraction and stretch have different effects on muscle protein turnover, but little is known about the metabolic effects of stretch. To investigate this, we assessed myofibrillar and sarcoplasmic protein synthesis (MPS, SPS, respectively) by incorporation of [1‐13C]proline (using gas chromatography–mass spectrometry) and anabolic signalling (by phospho‐immunoblotting and kinase assays) in cultured L6 skeletal muscle cells during 30 min of cyclic stretch and over 30 min intervals for up to 120 min afterwards. SPS was unaffected, whereas MPS was suppressed by 40 ± 0.03% during stretch, before returning to basal rates by 90–20 min afterwards. Paradoxically, stretch stimulated anabolic signalling with peak values after 2–30 min: e.g. focal adhesion kinase (FAK Tyr576/577; +28 ± 6%), protein kinase B activity (Akt; +113 ± 31%), p70S6K1 (ribosomal S6 kinase Thr389; 25 ± 5%), 4E binding protein 1 (4EBP1 Thr37/46; 14 ± 3%), eukaryotic elongation factor 2 (eEF2 Thr56; −47 ± 4%), extracellular regulated protein kinase 1/2 (ERK1/2 Tyr202/204; +65%± 9%), eukaryotic initiation factor 2α (eIF2α Ser51; −20 ± 5%, P < 0.05) and eukaryotic initiation factor 4E (eIF4E Ser209; +33 ± 10%, P < 0.05). After stretch, except for Akt activity, stimulatory phosphorylations were sustained: e.g. FAK (+26 ± 11%) for ≥30 min, eEF2 for ≥60 min (peak −45 ± 4%), 4EBP1 for ≥90 min (+33 ± 5%), and p70S6K1 remained elevated throughout (peak +64 ± 7%). Adenosine monophosphate‐activated protein kinase (AMPK) phosphorylation was unchanged throughout. We report for the first time that acute cyclic stretch specifically suppresses MPS, despite increases in activity/phosphorylation of elements thought to increase anabolism.
Focal adhesion kinase is a load‐dependent governor of the slow contractile and oxidative muscle phenotype
Authors: Durieux Anne‐Cécile , D’Antona Giuseppe , Desplanches Dominique , Freyssenet Damien , Klossner Stephan , Bottinelli Roberto , Flück Martin
Published: May 2009

Striated muscle exhibits a pronounced structural–functional plasticity in response to chronic alterations in loading. We assessed the implication of focal adhesion kinase (FAK) signalling in mechano‐regulated differentiation of slow‐oxidative muscle. Load‐dependent consequences of FAK signal modulation were identified using a multi‐level approach after electrotransfer of rat soleus muscle with FAK‐expression plasmid vs. empty plasmid‐transfected contralateral controls. Muscle fibre‐targeted over‐expression of FAK in anti‐gravitational muscle for 9 days up‐regulated transcript levels of gene ontologies underpinning mitochondrial metabolism and contraction in the transfected belly portion. Concomitantly, mRNA expression of the major fast‐type myosin heavy chain (MHC) isoform, MHC2A, was reduced. The promotion of the slow‐oxidative expression programme by FAK was abolished after co‐expression of the FAK inhibitor FAK‐related non‐kinase (FRNK). Elevated protein content of MHC1 (+9%) and proteins of mitochondrial respiration (+165–610%) with FAK overexpression demonstrated the translation of transcript differentiation in targeted muscle fibres towards a slow‐oxidative muscle phenotype. Coincidentally MHC2A protein was reduced by 50% due to protection of muscle from de‐differentiation with electrotransfer. Fibre cross section in FAK‐transfected muscle was elevated by 6%. The FAK‐modulated muscle transcriptome was load‐dependent and regulated in correspondence to tyrosine 397 phosphorylation of FAK. In the context of overload, the FAK‐induced gene expression became manifest at the level of contraction by a slow transformation and the re‐establishment of normal muscle force from the lowered levels with transfection. These results highlight the analytic power of a systematic somatic transgene approach by mapping a role of FAK in the dominant mechano‐regulation of muscular motor performance via control of gene expression.
Mechanotransduction and chemosensitivity of two major classes of bladder afferents with endings in the vicinity to the urothelium
Authors: Zagorodnyuk Vladimir P. , Brookes Simon J. H. , Spencer Nick J. , Gregory Sarah
Published: May 2009

The guinea pig bladder is innervated by at least five distinct major classes of extrinsic sensory neurons. In this study, we have examined the mechanisms of mechanotransduction and chemosensitivity of two classes of bladder afferents that have their endings in the vicinity of the urothelium: stretch‐sensitive muscle‐mucosal mechanoreceptors and stretch‐insensitive, mucosal high‐responding afferents. The non‐selective P2 purinoreceptor antagonist pyridoxal phosphate‐6‐azophenyl‐2′,4′‐disulphonic acid did not affect stretch‐ or stroking‐induced firing of these afferents but significantly reduced the excitatory action of α,β‐methylene ATP. Blocking synaptic transmission in Ca2+‐free solution did not affect stretch‐evoked firing but slightly reduced stretch‐induced tension responses. Stroking‐induced firing of both classes of afferents was also not affected in Ca2+‐free solution. Of blockers of mechano‐gated channels, benzamil (100 μm), but not amiloride (100 μm), Gd3+(100 μm) or SKF 96365 (50 μm), inhibited stretch‐ and stroking‐induced firing. Serotonin (100 μm) applied directly onto receptive fields predominantly activated muscle‐mucosal afferents. Muscarine (100 μm) and substance P (100 μm) in 24% and 36% cases activated only mucosal high‐responding units. Bradykinin (10 μm), but not prostaglandin E2 (10 μm), excites predominantly mucosal units. High (80 mm) K+solution activated both afferent classes, but responses of mucosal units were 4 times greater. In contrast to muscle‐mucosal units, most mucosal high‐responding units were activated by hot Krebs solution (45–46°C), low pH (pH 4) and capsaicin (3 μm). TRPV1 antagonist, capsazepine (10 μm) was without effect on mechanotransduction by mucosal high‐responding afferents. The results show that mechanotransduction of these two types of afferents are not dependant upon Ca2+‐dependent exocytotic release of mediators, or ATP, and it is likely that benzamil‐sensitive stretch‐activated ion channels on their endings are involved in direct mechanotransduction. The chemosensitivity to agonists and noxious stimuli differs significantly between these two major classes of bladder afferents that reflects their different physiological and pathophysiological roles in the bladder.
Time to fatigue is increased in mouse muscle at 37°C; the role of iron and reactive oxygen species
Authors: Reardon Trent F. , Allen David G.
Published: May 2009

Studies exploring the rate of fatigue in isolated muscle at 37°C have produced mixed results. In the present study, muscle fibre bundles from the mouse foot were used to study the effect of temperature on the rate of muscle fatigue. Provided iron was excluded from the solutions, time to fatigue at 37°C was increased compared to 22°C (125 ± 8% of 22°C fatigue time). In contrast, when iron was present (∼1 μm), fatigue was accelerated (68 ± 10%). Iron can increase reactive oxygen species (ROS), which are believed to accelerate fatigue. The addition of 25–100 μm H2O2 at 22°C reduced time to fatigue to 80–20% of the control, respectively. Iron was added to cultured primary skeletal muscle cells to determine if iron could increase ROS production. Neither iron entry nor ROS production were detected in non‐contracting muscle cells. The addition of 8‐hydroxyquinoline, which facilitates iron entry, to iron–ascorbic acid solutions caused a rapid rise in intracellular iron and ROS. Our results indicate that time to fatigue in vitro is increased at 37°C relative to 22°C, but the addition of ROS can accelerate fatigue. An increase in muscle iron can accelerate ROS production, which may be important during or following exercise and in haemochromatosis, disuse atrophy and sarcopenia.
Divergent regulation of GIRK1 and GIRK2 subunits of the neuronal G protein gated K+ channel by GαiGDP and Gβγ
Authors: Rubinstein Moran , Peleg Sagit , Berlin Shai , Brass Dovrat , Keren‐Raifman Tal , Dessauer Carmen W. , Ivanina Tatiana , Dascal Nathan
Published: May 2009

G protein activated K+ channels (GIRK, Kir3) are switched on by direct binding of Gβγ following activation of Gi/o proteins via G protein‐coupled receptors (GPCRs). Although Gαi subunits do not activate GIRKs, they interact with the channels and regulate the gating pattern of the neuronal heterotetrameric GIRK1/2 channel (composed of GIRK1 and GIRK2 subunits) expressed in Xenopus oocytes. Coexpressed Gαi3 decreases the basal activity (Ibasal) and increases the extent of activation by purified or coexpressed Gβγ. Here we show that this regulation is exerted by the ‘inactive’ GDP‐bound Gαi3GDP and involves the formation of Gαi3βγ heterotrimers, by a mechanism distinct from mere sequestration of Gβγ‘away’ from the channel. The regulation of basal and Gβγ‐evoked current was produced by the ‘constitutively inactive’ mutant of Gαi3, Gαi3G203A, which strongly binds Gβγ, but not by the ‘constitutively active’ mutant, Gαi3Q204L, or by Gβγ‐scavenging proteins. Furthermore, regulation by Gαi3G203A was unique to the GIRK1 subunit; it was not observed in homomeric GIRK2 channels. In vitro protein interaction experiments showed that purified Gβγ enhanced the binding of Gαi3GDP to the cytosolic domain of GIRK1, but not GIRK2. Homomeric GIRK2 channels behaved as a ‘classical’ Gβγ effector, showing low Ibasal and strong Gβγ‐dependent activation. Expression of Gαi3G203A did not affect either Ibasal or Gβγ‐induced activation. In contrast, homomeric GIRK1* (a pore mutant able to form functional homomeric channels) exhibited large Ibasal and was poorly activated by Gβγ. Expression of Gαi3GDP reduced Ibasal and restored the ability of Gβγ to activate GIRK1*, like in GIRK1/2. Transferring the unique distal segment of the C terminus of GIRK1 to GIRK2 rendered the latter functionally similar to GIRK1*. These results demonstrate that GIRK1 containing channels are regulated by both Gαi3GDP and Gβγ, while GIRK2 is a Gβγ‐effector insensitive to Gαi3GDP.
The role of phosphoinositide 3‐kinase and phosphatidic acid in the regulation of mammalian target of rapamycin following eccentric contractions
Authors: O’Neil T. K. , Duffy L. R. , Frey J. W. , Hornberger T. A.
Published: May 2009

Resistance exercise induces a hypertrophic response in skeletal muscle and recent studies have begun to shed light on the molecular mechanisms involved in this process. For example, several studies indicate that signalling by the mammalian target of rapamycin (mTOR) is necessary for a hypertrophic response. Furthermore, resistance exercise has been proposed to activate mTOR signalling through an upstream pathway involving the phosphoinositide 3‐kinase (PI3K) and protein kinase B (PKB); however, this hypothesis has not been thoroughly tested. To test this hypothesis, we first evaluated the temporal pattern of signalling through PI3K–PKB and mTOR following a bout of resistance exercise with eccentric contractions (EC). Our results indicated that the activation of signalling through PI3K–PKB is a transient event (<15 min), while the activation of mTOR is sustained for a long duration (>12 h). Furthermore, inhibition of PI3K–PKB activity did not prevent the activation of mTOR signalling by ECs, indicating that PI3K–PKB is not part of the upstream regulatory pathway. These observations led us to investigate an alternative pathway for the activation of mTOR signalling involving the synthesis of phosphatidic acid (PA) by phospholipase D (PLD). Our results demonstrate that ECs induce a sustained elevation in [PA] and inhibiting the synthesis of PA by PLD prevented the activation of mTOR. Furthermore, we determined that similar to ECs, PA activates mTOR signalling through a PI3K–PKB‐independent mechanism. Combined, the results of this study indicate that the activation of mTOR following eccentric contractions occurs through a PI3K–PKB‐independent mechanism that requires PLD and PA.
Predictions of Tire-Terrain Interaction Using Finite Element Analysis Models
Authors: Allen James , Shoffner Brent , O¨ijer Fredrik , El-Gindy Moustafa , Trivedi Mukesh , Johansson Inge
Published: May 2009

Simplified Finite Element Analysis (FEA) truck tire models are developed and used to examine the interaction between the tire and various types of terrain. Soft terrain such as hard soil and dry sand is modeled using solid, elastic-plastic elements. The general trends of vertical and longitudinal forces and normal and shear stress distributions in the soft soil are compared with published data for preliminary validation. The cornering characteristics on both rigid and soft soil terrains are also predicted and compared. Additionally, a detailed FEA truck tire is introduced as the next phase of this work.
Fabrication of PLGA Microstructures Made Up of Circular Microchannels Using Soft Lithography
Authors: Wang Gou-Jen , Hsueh Cheng-Chih
Published: May 2009

A simple micromolding method to fabricate PLGA microstructures made up of microchannels with circular cross section is presented. The thermal reflow technique is adopted to fabricate the semi-cylindrical photoresist master. The PLGA solution is prepared by dissolving PLGA polymer in acetone and then casting the solution onto the semi-cylindrical photoresist master to produce PLGA microstructures. Two PLGA membranes are bonded together to form the circular microchannels consisted microstructures. A microvessel scaffold for tissue engineering by implementing the proposed method is fabricated. Roundness of the microchannels is verified.
The Bifurcation Analysis of High-Speed Vehicle and Mechanism of Jumping Rail
Authors: Wang Wei , Li Guixian , Yu Guangbin
Published: May 2009

The dynamics phenomena of half railway carriage model with 17 degrees of freedom are investigated. The model is set to run on a straight track with the speed range between 85 and 165m/s. Shen-Hedrick-Elkins theory is used to describe the nonlinear relation between the creepage and the creep forces. A new method of flange contact as multi-body collision is also presented. Bifurcation diagram and the critical speed for jumping rail are obtained and further validated by the simulation. Finally, the phase plots of the flange contact are discussed.
Nanomechanics of Peeling Studied Using the Atomic Force Microscope
Authors: Strus Mark C. , Raman Arvind , Zalamea Luis , Pipes R. Byron , Nguyen Cattien V.
Published: May 2009

Through adaptation of an atomic force microscope, we have developed a peel test at the micro- and nanoscale level that has the capability of investigating how long flexible nanotubes, nanowires, nanofibers, proteins, and DNA adhere to various substrates. This novel atomic force microscopy (AFM) peeling mode extends existing AFM “pushing” and “pulling” force spectroscopies by offering practical knowledge about the complex interplay of nonlinear flexure, friction, and adhesion when one peels a long flexible molecule or nanostructure off a substrate. The static force peeling spectroscopies of straight multiwalled carbon nanotubes suggest that a significant amount of the total peeling energy is channeled into nanotube flexure. Meanwhile dynamic force spectroscopies offer invaluable information about the dissipative physical processes involved in opening and closing a small “crack” between the nanotube and substrate.
A Full Vehicle Model for the Development of a Variable Camber Suspension
Authors: Kuwayama Isao , Baldoni Fernando , Cheli Federico
Published: May 2009

The accuracy of the recent vehicle dynamics simulation technology, represented by Multi-Body Simulations along with reliable tire models, has been remarkably progressing and provides reasonable simulation results not only for conventional passive vehicles but also for advanced active vehicles equipped with electronic components; however, when it comes to advanced vehicle applications with complex active systems, the complexity causes a longer simulation time. On the other hand, even though simple numerical vehicle simulation models such as single-track, two-track and a dozen degrees of freedom (dofs) models can provide less information than those of multi-body models, they are still appreciated by specific applications particularly the ones related to the development of active systems. The advantages of these numerical simulation models lie in the simulation platform, namely the Matlab/Simulink environment, which is suitable for modeling electronic components. In this paper, an 18 dofs vehicle model has been proposed for the development of a type of active suspension named Variable Camber which has an additional degree of freedom in camber angle direction and a description of the models and some preliminary results are reported: the control strategy for the variable camber suspension will be published ([3]). The model can reproduce a passive vehicle with a passive suspension as well; all the necessary dimensions, parameters, and physical properties are derived from a specific multi-body full vehicle model which has been fully validated with respect to a real one on the track. As for a tire model, Magic Formula 5.2 has been implemented on both the numerical and the multi-body vehicle models respectively so that the same tire model can be applied.
Attempt of Prediction of Vehicle Longitudinal Dynamic Performance Using Artificial Neural Networks (ANN)
Authors: Albers Albert , Ott Sascha , Wang Jiangang
Published: May 2009

This paper proposes a method that is based on ANN for monitoring of the vehicle behavior. Considering the control loop of driver-vehicle-environment a driver should perceive the environment and the vehicle behavior by processing received information from the environment and feedback from the vehicle. The precession of the driver’s percipience is the critical element in such case. In this study, an ANN is applied for perception and prediction of the vehicle dynamic performance. Several relevant parameters from the vehicle and the environment, such as accelerator pedal travel and road grade, serve as information for the prediction. After training of the network with the measured data from a test vehicle, the network will be used for prediction of the driving speed. The comparison of the measured driving speed with the predicted speed can indicate the actual performance of the vehicle, see Figure 1.
A Dynamic Light-Duty Vehicle Model: Validation With Indoor and Outdoor Experimental Tests
Authors: Cheli Federico , Sabbioni Edoardo
Published: May 2009

A Multi-Body vehicle model aimed at reproducing the vertical dynamics of a light-duty commercial vehicle is presented in this paper. In order to properly model the vehicle and to identify some unknown structural parameters, experimental tests have been carried on a four-post test rig and on ordinary roads.
Identification of Pacejka’s Coefficients Through Full Vehicle Experimental Tests
Authors: Cheli Federico , Braghin Francesco , Resta Ferruccio , Sabbioni Edoardo
Published: May 2009

A methodology aimed at identifying the MF-Tyre model coefficients for the steady-state pure cornering condition is presented in this paper. Only the measurements carried out on board vehicle during standard handling manoeuvres (step-steer) are considered by the identification procedure. The proposed methodology is made of three subsequent steps. During the first phase the axles cornering forces are identified through an extended Kalman filter. Then the vertical loads and the slip angles at each tire are estimated. The results of these two steps are passed as an input to the last phase, during which through a constrained minimization approach, the MF coefficients are identified. The identification procedure has been applied to the experimental data collected on an instrumented sport car.
A Monte Carlo Finite Element Method for Determining the Young’s Modulus of Polymer Nanocomposites Using Nanoindentation Data
Authors: Kontsos A. , Spanos P. D.
Published: May 2009

This article presents a Monte Carlo finite element method (MCFEM) for determining the Young’s modulus (YM) of polymer nanocomposites (PNC) using Nanoindentation (NI) data. The method treats actual NI data as measurements of the local YM of PNC; it further assesses the effect of the nonhomogeneous dispersion of carbon nanotubes in polymers on the statistical variations observed in experimental NI data. First the method simulates numerically NI data by developing a random field and a multiscale homogenization model. Subsequently, the MCFEM applies the spectral representation method to generate a population of samples of local YM values. These local values are then used in conjunction with a stochastic finite element scheme to derive estimates for the YM of PNC. The statistical processing of the ensemble of FE solutions yields overall YM values that agree well with corresponding results reported in the literature.
A Torque Vectoring Control Logic for Active High Performance Vehicle Handling Improvement
Authors: Cheli Federico , Kakalis Leonidas , Zorzutti Andrea
Published: May 2009

The most common automotive drivelines transmit the engine torque to the driven axle through the differential. Semi-active versions of such device ([10], [11], [12]) have been recently conceived to improve vehicle handling at limit and in particular maneuvers. All these differentials are based on the same structural hypothesis of the passive one but they try to manipulate the vehicle dynamics controlling a quantity which was fixed in the passive mechanisms. In this way it’s possible to control the amount of the stabilizing torque but it’s not possible to apply it in both directions. This fact is a great draw drawback of the semi-active differential because a complete yaw control can’t be developed. On the other hand, active differentials [17] can both apply the best yaw moment (in terms of amplitude) and do this with the right sign. Although classic active differentials are greatly versatile, they can’t (or hardly can) reproduce an extreme torque distribution as 0–100% when there is not a μ-split condition. That is because there is always a bias value due to the presence of a gear that has to be decreased by active clutch action. And these clutches are often not able to do that. The most innovative device presented in the last years is the Super Handling-All Wheel Drive (SH-AWD) by Honda ([2], [3], [4], [5]). It can freely distribute the drive torque to the desired wheel, maintaining one of them in free rolling condition, if this is necessary. This flexibility in the lateral torque distribution can hugely increase the vehicle manoeuvrability. Author has carried out a feasibility study to evaluate the handling improvement due to such a device on a high performance rear wheel drive vehicle normally equipped with a semi-active differential.
Organization of Collaborative Decision Making to Form Design Processes
Authors: Chen Zhiqiang , Siddique Zahed
Published: May 2009

Design and development of a product requires considering different aspects of the product through coordination, negotiation, and discussion in a collaborative environment. Each participant plays a role as a stakeholder, generating information from his/her viewpoints or perspectives, which influence the design through his/her design decisions. Collaboration is essential in a design process to avoid decision making mistakes, to shorten design time, and to improve design quality. Specific focuses on design collaboration in this paper are: (i) Modeling collaborative design process; and (ii) Implementing design system to support real-time and synchronized group design activities.
Attribute Attribute-Based Clustering for Product Family Design
Authors: Ye Xiaoli , Gershenson John K.
Published: May 2009

As manufacturers are forced by today’s marketplace to provide nearly customized products to satisfy individual customer requirements and simultaneously achieve economies of scale during production, product family design and platform-based product development have garnered their attention. Determining which elements (attributes, functions, components, etc.) should be made common, variable, or unique, across a product family is the critical step in the successful implementation of product families and product platforms. Therefore, the inherent challenge in product family design is to balance the tradeoff between product commonality (how well the components and functions can be reused across a product family) and variety (the range of different products in a product family). There are opportunities to develop tools to directly aid in addressing the commonality/variety tradeoff at the product family planning stage in a way that supports the engineering design process. In this paper, we develop a matrix-based, qualitative design tool – the Attribute-Based Clustering Methodology (ABCM) that enables the design of product families to better satisfy the ideal commonality/variety tradeoff as determined by a company’s competitive focus. The ABCM is used to identify component commonality opportunities in product families without sacrificing product variety by analyzing product attributes across the product family. This paper focuses on the ABCM as used in new product family design and how the ABCM can be used to cluster product attributes into potential modules and product platforms. It is intended as a starting place, an opening set of questions, and as a framework for the general solution to the problem of a qualitative design tool for product family design that directly address the commonality/variety tradeoff. Development of the ABCM starts with the classification of existing product attributes into three categories: common, unique, and variable. The attributes are then clustered into platforms and differentiating modules based on their occurrences, target value ranges (partitioning the target values for each product attribute into achievable ranges), and the manner in which the range changes across the entire target market segments. The ABCM can be used as a qualitative guideline in product family design. In new product family design, it can be used to identify which elements (functions and components) should be clustered into a common platform and which should be clustered into differentiating modules based on an analysis of the product attributes, their occurrences, and their target values across the product family. In product family redesign, the ABCM can be used to identify any elements that are inappropriately included in a platform or inappropriately clustered into differentiating modules by comparing the ideal clustering with the actual clustering.
Scenario Graph: Discovering New Business Opportunities and Failure Modes
Authors: Kim Sun K. , Ishii Kosuke , Beiter Kurt A.
Published: May 2009

Companies struggle to identify new business opportunities based on their core competence be it products or services. When a company focuses on improving current offerings or is too involved in them, it has difficulty discovering new applications for them. Scenario Graph is an original design method for products or services that aids design teams to envision four types of information while in the market definition phase: potential user locations, activities associated with the location, user circumstances, and the corresponding user state. By using Scenario Graph, design teams are better able to capture new values, scenarios, and behaviors of potential customers. This knowledge captured in the fuzzy front end stage can then be translated into inputs to other Design for X (dfX) tools to improve the definition of the product or service. Another benefit of the tool is that it directs the design team to discover unidentified failure modes of the current offerings by identifying unintended user scenarios. In this paper, a detailed guide, along with case studies demonstrates the usefulness of the tool when applied in the early phase of product or service development. Scenario Graph will assist design teams and managers in discovering new product or service opportunities.
Development of a Template Design Support System
Authors: Goto Norihiko , Koga Tsuyoshi , Okamura Shin , Aoyama Kazuhiro
Published: May 2009

A major problem in product design is that the design process is not clear to designers. Therefore, every time designers develop a new product, they face difficulties in determining the order in which the product attributes should be determined, especially in the case of large, complicated products. This problem mainly occurs due to two reasons. First, the knowledge about past product designs is not well arranged and thus there is no way to utilize it. Therefore, this research focuses on developing a design support system that proposes a design process in which the designer can easily reflect the important attributes of a product while facing less difficulties in completing the design; this is done using a topdown design support system. In a top-down design system, the designer expresses the product knowledge using elements such as entity, attribute, constraint, interface, etc. Further, five types of knowledge are expressed in this system. They are: knowledge about product structure, knowledge about product entity, knowledge about product function, knowledge about product constraint, and knowledge about product design process. Since this research focuses on the design process, extracting knowledge about the product design process is very important. To extract this knowledge, we first compare the template of past products and the product currently being designed. Next, we calculate the consistency of the two models. Then, based on the results of the consistency calculation, we select and extract the available knowledge. We create a new process by using this extracted knowledge from the design template. It is possible to produce more than one process by combining the knowledge from more than one template. Finally, we evaluate the process from three perspectives: whether it is easy to reflect the customer requirements, whether the design conflict difficulty is small, and whether the design loop difficulty is small. Based on the evaluation result, the designers can select a process to design a new product. In this research, the ocean thermal energy conversion (OTEC) system is used as an example. Further, a process that can easily design the important attributes with a smaller possibility of breakdown than the existing process is chosen based on the results of applying a model proposed by this research. A well-organized design process has been achieved in the OTEC example. Future works must focus on improving the evaluation of the design process and the method for expressing the design knowledge as a template.
Degree Operations on Periodic Surfaces
Authors: Wang Yan
Published: May 2009

In previous work, a periodic surface model for computer-aided nano-design (CAND) was developed. This implicit surface model can construct Euclidean and hyperbolic nano geometries parametrically and represent morphologies of particle aggregates and polymers. In this paper, we study the characteristics of degree elevation and reduction based on a generalized periodic surface model. Methods of degree elevation and reduction operations are developed in order to support multi-resolution representation and model exchange.