bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo comparison of norepinephrine and dopamine release in rat brain by simultaneous measurements with fast‐scan cyclic voltammetry
Authors: Park Jinwoo , Takmakov Pavel , Wightman R. Mark
Published: September 2011

J. Neurochem. (2011) 119, 932–944.

Brain norepinephrine and dopamine regulate a variety of critical behaviors such as stress, learning, memory, and drug addiction. In this study, we demonstrate differences in the regulation of in vivo neurotransmission for dopamine in the anterior nucleus accumbens (NAc) and norepinephrine in the ventral bed nucleus of the stria terminalis (vBNST) of the anesthetized rat. Release of the two catecholamines was measured simultaneously using fast‐scan cyclic voltammetry at two different carbon‐fiber microelectrodes, each implanted in the brain region of interest. Simultaneous dopamine and norepinephrine release was evoked by electrical stimulation of a region where the ventral noradrenergic bundle, the pathway of noradrenergic neurons, courses through the ventral tegmental area/substantia nigra, the origin of dopaminergic cell bodies. The release and uptake of norepinephrine in the vBNST were both significantly slower than for dopamine in the NAc. Pharmacological manipulations in the same animal demonstrated that the two catecholamines are differently regulated. The combination of a dopamine autoreceptor antagonist and amphetamine significantly increased basal extracellular dopamine whereas a norepinephrine autoreceptor antagonist and amphetamine did not change basal norepinephrine concentration. α‐Methyl‐p‐tyrosine, a tyrosine hydroxylase inhibitor, decreased electrically evoked dopamine release faster than norepinephrine. The dual‐microelectrode fast‐scan cyclic voltammetry technique along with anatomical and pharmacological evidence confirms that dopamine in the NAc and norepinephrine in the vBNST can be monitored selectively and simultaneously in the same animal. The high temporal and spatial resolution of the technique enabled us to examine differences in the dynamics of extracellular norepinephrine and dopamine concurrently in two different limbic structures.
Evaluation of the effect of one large dose of erythropoietin against cardiac and cerebral ischemic injury occurring during cardiac surgery with cardiopulmonary bypass: a randomized double‐blind placebo‐controlled pilot study
Authors: Joyeux‐Faure Marie , Durand Michel , Bedague Damien , Protar Daniel , Incagnoli Pascal , Paris Adeline , Ribuot Christophe , Levy Patrick , Chavanon Olivier
Published: September 2011

Cardiac surgery and cardiopulmonary bypass (CPB) induce ischemia–reperfusion and subsequent cellular injury with inflammatory reaction. Clinical and experimental studies suggest that recombinant human erythropoietin (EPO) independently of its erythropoietic effect may be used as a cytoprotective agent against ischemic injury. We tested the hypothesis that one large dose of EPO administered shortly before CPB prevents the elevation of cardiac and cerebral ischemic blood markers as well as the systemic inflammatory response induced by cardiac surgery with CBP through this randomized double‐blind placebo‐controlled pilot trial. Fifty patients scheduled for coronary artery bypass graft (CABG) surgery with CPB were randomly allocated to EPO or control groups. EPO (800 IU/kg intravenously) or placebo (saline) was administered before CPB. The primary end point was to study the effect of EPO administration on several blood markers of myocardial and cerebral ischemia in relation to CABG with CPB. In both groups, surgery increased plasma concentrations of cardiac (troponin T, NT‐proBNP, and creatine kinase MB) and cerebral (S100β protein) markers ischemic as well as the pro‐inflammatory marker interleukin‐6. Compared with the placebo, EPO administration before CPB did not prevent an increase of all these markers following CPB. In conclusion, one large dose of EPO, given shortly before CPB, did not protect against cardiac and cerebral ischemia and inflammatory response occurring during CABG surgery with CPB. Although the long‐term clinical implications remain unknown, the findings do not support use of EPO at this dose as a cytoprotective agent in patients undergoing cardiac surgery.
Factors associated with seizure freedom in the surgical resection of glioneuronal tumors
Authors: Englot Dario J. , Berger Mitchel S. , Barbaro Nicholas M. , Chang Edward F.
Published: September 2011

Purpose:  Gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNETs) are low‐grade brain tumors of glioneuronal origin that commonly present with seizures. Achieving seizure control in patients with glioneuronal tumors remains underappreciated, as tumor‐related epilepsy significantly affects patients’ quality‐of‐life.

Methods:  We performed a quantitative and comprehensive systematic literature review of seizure outcomes after surgical resection of GGs and DNETs associated with seizures. We evaluated 910 patients from 39 studies, and stratified outcomes according to several potential prognostic variables.

Key Findings:  Overall, 80% of patients were seizure‐free after surgery (Engel class I), whereas 20% continued to have seizures (Engel class II–IV). We observed significantly higher rates of seizure‐freedom in patients with ≤1 year duration of epilepsy compared to those with >1 year of seizures [odds ratio (OR) 9.48; 95% confidence interval (CI) 2.26–39.66], and with gross‐total resection over subtotal lesionectomy (OR 5.34; 95% CI 3.61–7.89). In addition, the presence of secondarily generalized seizures preoperatively predicted a lower rate of seizure‐freedom after surgery (OR 0.40; 95% CI 0.24–0.66). Outcomes did not differ significantly between adults and children, patients with temporal lobe versus extratemporal tumors, pathologic diagnosis of GG versus DNET, medically controlled versus refractory seizures, or with the use of electrocorticography (ECoG). Extended resection of temporal lobe tumors, with hippocampectomy and/or corticectomy, conferred additional benefit.

Significance:  These results suggest that early operative intervention and gross‐total resection are critically important factors in achieving seizure‐freedom, and thus improving quality‐of‐life, in patients with glioneuronal tumors causing epilepsy.
Pre‐engraftment syndrome after unrelated donor umbilical cord blood transplantation in patients with hematologic malignancies
Authors: Wang Xingbing , Liu Huilan , Li Lailing , Geng Liangquan , Ding Kaiyang , Liu Xin , Tong Juan , Zhu Weibo , Sun Zimin
Published: September 2011

Pre‐engraftment syndrome (PES) after umbilical cord blood transplantation (CBT) remains poorly characterized, and the prognosis and appropriate management are unclear. Therefore, we retrospectively analyzed the incidence, risk factors, manifestations, and clinical outcomes of PES in CBT recipients, who had been treated for hematologic malignancies at our transplantation center. PES was defined as unexplained fever higher than 38.3°C that is not associated with documented infection and unresponsive to antimicrobial manipulations and/or unexplained erythematous skin rash occurring prior to neutrophil engraftment. A total of 81 patients (median 18 yr, range 3–48) received either myeloablative (n = 72) or non‐myeloablative (n = 9) conditioning. Neutrophil engraftment was achieved in 69 of the 81 cases [86.2%, 95% confidence interval (CI) = 78.9–94.1%], and the median time to more than 0.5 × 109/L ANC was 19 d (range, 12–39). Fifty‐one patients (63.0%) developed PES at a median of 7 d (range 3–15) post‐transplant: 46 patients had both rash and unexplained fever; one patient had unexplained fever alone; and four patients had rash only. Forty‐seven patients (92.2%) received IV methylprednisolone (MP) at a median dose of 1 mg/kg (range 0.4–3). All patients treated with MP responded as evidenced by fever resolution combined with resolution of rash. All patients with PES had high serum levels of C‐reactive protein (CRP), which were significantly reduced after effective steroid treatment. Univariate analysis identified myeloablative conditioning and younger age as significant risk factors for developing PES. Cumulative incidence of grade II–IV acute graft‐versus‐host disease (aGVHD) in the PES+ and PES− groups was 51.5% (95% CI = 38.0–70.0%) and 17.0% (95% CI = 6.9–41.7%), respectively. In a multivariate analysis, we found significantly increased risk of grade II–IV aGVHD among PES patients (P = 0.041). However, PES was not associated with sustained donor engraftment, the day to neutrophil recovery, chronic graft‐versus‐host disease, transplant‐related mortality at day 180, and overall survival. Despite of the inherent limitations of this small retrospective study, PES seemed to be common after CBT and associated with high incidence of aGVHD.
Pulp regeneration after non‐infected and infected necrosis, what type of tissue do we want? A review
Authors: Andreasen Jens O. , Bakland Leif K.
Published: September 2011

Abstract –  Regeneration (revitalization) of infected necrotic pulp tissue has been an important issue in endodontics for more than a decade. Based on a series of case reports, there appears to be evidence that new soft tissue can enter the root canal with a potential for subsequent hard tissue deposition resulting in a narrowing of the root canal. Very little is presently known about the exact nature of this tissue growing into the canal and how it may behave in the long term. In the case of regeneration of necrotic non‐infected pulp tissue, a series of clinical and histological studies have shown that such events may take place in four variants: (i) Revascularization of the pulp with accelerated dentin formation leading to pulp canal obliteration. This event has a good long‐term prognosis. (ii) Ingrowth of cementum and periodontal ligament (PDL). The long‐term prognosis for this event is not known. (iii) Ingrowth of cementum, PDL, and bone. The long‐term prognosis is only partly known, but cases developing an internal ankylosis have been described. (iv) Ingrowth of bone and bone marrow is a rare phenomenon and the long‐term prognosis does not appear to be good. Based on current knowledge, expectations with respect to pulp regeneration (revitalization) of infected necrotic dental pulps are difficult to predict; more information than now available is needed before procedures for pulpal regeneration can be routinely recommended with a predictable long‐term prognosis.
Vegetation dynamics of endemic‐rich quartz fields in the Succulent Karoo, South Africa, in response to recent climatic trends
Authors: Schmiedel Ute , Dengler Jürgen , Etzold Sophia
Published: September 2011

Question

How do species composition and abundance change in the medium term and can the detected fluctuations and trends be attributed to weather conditions or climate change?

Location

Quartz fields of the Knersvlakte, Succulent Karoo, South Africa, a plant diversity hotspot.

Methods

We monitored vascular plant composition and abundance of all taxa on 12 permanent plots (25 m²) over a period of 12 yr. With multiple regressions, we tested the effect of rainfall in different periods on species richness and abundance.

Results

The plots showed significant inter‐annual changes in population size, species richness and species composition. In general, plant populations showed a significant positive trend over the 12 yr analysed, while therophytes decreased significantly. Number of chamaephyte and geophyte individuals was positively influenced by rainfall of the preceding year, whereas therophytes were significantly positively influenced by rainfall of the same year.

Conclusions

We conclude that the increase in inter‐annual variability of rainfall has so far had no negative effects on the quartz field vegetation. However, observations of recent climatic trends and climate change projections suggest that there will be much stronger changes in rainfall and temperature patterns in the next decades. Continuous long‐term monitoring of biodiversity is thus crucial to understand potential impacts of climate change in the Knersvlakte.
HIGH‐RESOLUTION COMPUTED TOMOGRAPHY BRONCHIAL LUMEN TO PULMONARY ARTERY DIAMETER RATIO IN ANESTHETIZED VENTILATED CATS WITH NORMAL LUNGS
Authors: Reid Lauren E. , Ray Dillon A. , Hathcock John T. , Brown Lawrence A. , Tillson Michael , Wooldridge Anne A.
Published: September 2011

High‐resolution computed tomography (CT) is the preferred noninvasive tool for diagnosing bronchiectasis in people. A criterion for evaluating dilation of the bronchus is the bronchial lumen to pulmonary artery diameter (bronchoarterial ratio [BAratio]). A ratio of >1.0 in humans or >2.0 in dogs has been suggested as a threshold for identifying bronchiectasis. The purpose of this study was to establish theBAratio in normal cats. Fourteen specific pathogen‐free cats were selected for analysis of thoracicCTimages. TheBAratios of the lobar bronchi of the left cranial (cranial and caudal parts), right cranial, right middle, left caudal, and right caudal lung lobes were measured. The mean of the meanBAratio of all lung lobes was 0.71 ± 0.05. IndividualBAratios ranged from 0.5 to 1.11. Comparing individual lobes for each cat, there was no significant difference (P= 0.145) in meanBAratio between lung lobes. A meanBAratio for these normal cats was 0.71 ± 0.1, which suggests an upper cut‐off normal value > 0.91 (mean ± 2 standard deviations) between normal and abnormal cats.
HYDROCARBON HABITAT OF THE SEDANO TROUGH, BASQUE‐CANTABRIAN BASIN, SPAIN
Authors: Beroiz C. , Permanyer A.
Published: September 2011

This paper analyzes the hydrocarbon habitat and potential of the Sedano trough in the SW sector of the Basque‐Cantabrian Basin (northern Spain). The study is based on regional geological data, geochemical analyses, basin modelling simulations and play analysis techniques, and attempts to quantify by volumetric resource appraisal the volume of hydrocarbons generated, expelled and migrated from the main Sedano trough depocentre.

A Lower Jurassic shale source rock has been identified and is responsible for the oil at Ayoluengo field, for the oil shows at the Polientes and Tozo wells, and for the Zamanzas and Basconcillos de Tozo tar sands which outcrop at the NE and SW margins of the Sedano trough respectively. Thermal history modelling indicates that petroleum generation and expulsion from the Lower Jurassic source rock started in the Sedano trough in the Early Cretaceous, with the main oil generation phase occurring in latest Cretaceous to Paleogene times.

GC, GC‐MS and isotopic analyses of oils, tar sands and source rock extracts from the Sedano trough indicate good correlations between the Lower Jurassic source rock and the Ayoluengo oil, and tar sands from the basin margins.

Petroleum plays and traps are abundant and are a result of a complex polyphase geological history. They can be grouped into:(i) early salt‐induced structural plays; (ii) later structural plays associated with a mid‐Tertiary compressional phase; and (iii) stratigraphic plays within the Upper Jurassic – Lower Cretaceous siliciclastic succession.

A volumetric resource appraisal of the Lower Jurassic source rock indicates that a total of 11 billion bbl of oil could have been generated and expelled in the Sedano trough, and around 880 million bbl of oil have migrated into potential traps in 15 identified drainage areas. This results in a generation‐accumulation efficiency of 7%. Undiscovered resources have been estimated at 154 million bbl of oil, indicating that there is still moderate undiscovered hydrocarbon potential in the area.
Alpha‐actinin‐3 deficiency does not significantly alter oxidative enzyme activity in fast human muscle fibres
Authors: Vincent B. , Windelinckx A. , Van Proeyen K. , Masschelein E. , Nielens H. , Ramaekers M. , Van Leemputte M. , Hespel P. , Thomis M.
Published: September 2011

Aim:  In Western European populations, about 18% of all individuals have a complete deficiency of the alpha‐actinin‐3 protein owing to homozygosity for a stop codon mutation (R577X) in the ACTN3 gene. Actn3−/− knock‐out mice show increased activity of multiple enzymes in the aerobic metabolic pathway in fast muscle fibres. Whether this observation is also present in human XX genotype carriers compared to RR carriers has not been studied in a fibre‐type‐specific approach in humans. The purpose of this study was therefore to compare fibre‐type‐specific oxidative enzyme activity in humans with a different ACTN3 R577X genotype.

Methods:  Vastus lateralis muscle biopsy samples of 17 XX and 16 RR subjects were used to measure markers of oxidative capacity [cytochrome c oxidase (CYTOX) and succinate dehydrogenase (SDH)] in a fibre‐type‐specific assay using enzyme histochemistry.

Results:  Cytochrome c oxidase staining showed no significant genotype group differences in type I or type II muscle fibres. Also, we found no significant differences in SDH staining of fast fibres comparing XX and RR carriers.

Conclusion:  In conclusion, the increase in oxidative enzyme activity of fast muscle fibres, as reported in an Actn3−/− knock‐out mouse, was not observed in our human samples. Known differences in metabolic characteristics of muscle fibres in rodents compared to humans may in part explain this discrepancy in findings.
Internal Transcribed Spacer as a Target to Assess Yeast Biodiversity in Italian Taleggio PDO Cheese
Authors: Giannino Maria L. , Buffoni Joanna N. , Massone Elisabetta , Feligini Maria
Published: September 2011

Abstract:  Three batches of soft smear‐ripened Taleggio PDO cheese were made in Northern Italy during the summertime 2010. A total of 129 isolates cultured from cheese surface were examined by using PCR‐based methods and sequencing of both the ITS1 region and D1 and D2 domains of the 26S rRNA gene. Sequence analysis of isolates brought to the identification of 6 species: Debaryomyces hansenii, Kluyveromyces lactis, Kluyveromyces marxianus, Yarrowia lipolytica, Pichia guilliermondii, and Torulaspora delbrueckii. Analysis of DNA directly extracted from 45 cheese surfaces permitted to detect 2 additional species Candida sake and Candida etchellsii. D. hansenii was predominant and widespread whereas the other yeast species were detected less frequently. To determine the relationships between yeast community and the environment, 39 isolates from wooden boxes used for dry salting of cheese were analyzed as well. Sequencing of ITS1 region allowed to identify D. hansenii, T. delbrueckii, and K. lactis. ITS1 multiple sequence alignments of D. hansenii detected in wooden boxes showed an in‐del polymorphism at position 169. ITS1 secondary structures of yeasts were modeled to explore new applications of this region for molecular identification purposes.

Practical Application:  This study used molecular analysis to identify adventitious yeast population present in the surface of Taleggio smear‐ripened cheese. D. hansenii was found predominant in pasteurized milk, in dry salting equipment, and in all cheese samples until the end of ripening.
Effect of γ‐Irradiation on Bioactivity, Fatty Acid Compositions and Volatile Compounds of Clary Sage Seed (Salvia sclarea L.)
Authors: Yalcin Hasan , Ozturk Ismet , Tulukcu Eray , Sagdic Osman
Published: September 2011

Abstract:  Clary sage seeds (Salvia sclarea L.) were obtained from plants cultivated, and 2.5, 4.0, 5.5, and 7.0 kGy doses of γ‐irradiation were applied to the clary sage seeds. They were then analyzed for their protein, ash, oil and dry matter contents, and fatty acid composition. Additionally, the total phenolic contents, antiradical, antioxidant activities, and volatile compounds of the clary sage seed extract were determined. There was no significant difference in protein content. However, the moisture, oil, and ash contents of the samples were affected by irradiation. While the 7 kGy dose had a positive effect on the total phenolic content and antiradical activity of the sage seed extract, all doses have negative effects on the antioxidant activity of the sage seed. The main fatty acid of the sage seed was remarkably found as α‐linolenic acid. The four irradiation levels caused significant differences in fatty acid composition by affecting all fatty acids except palmitic, palmitoleic, and eicosenoic acids. The dominant volatile compounds of control sage seed were found as β‐pinene (18.81%) and limonene (15.60%). Higher doses of the irradiation decreased volatile components of sage seed. Clary sage seed including high omega‐3 can be irradiated with low doses (≤2.5 kGy) of γ‐irradiation.

Practical Application:  Clary sage is one of the most popular Salvia species in Turkey and many countries. Clary sage seed has approximately 29% oil content and this oil contains >50% of α‐linolenic acid. γ‐Irradiation is widely applied in the preservation of spice quality. The present study shows that the antioxidant activity of the clary sage seed is decreased by γ‐irradiation. Additionally, higher doses of irradiation also decreased the volatile components of sage seed. Therefore, we suggest that clary sage seed which includes high levels of omega‐3 should be irradiated with low doses (≤2.5 kGy) of γ‐irradiation.
Range expansion and enemy recruitment by eight alien gall wasp species in Britain
Authors: SCHÖNROGGE KARSTEN , BEGG TRACEY , WILLIAMS ROBIN , MELIKA GEORGE , RANDLE ZOË , STONE GRAHAM N.
Published: September 2011

Abstract.  1. Biological invasions involving continuous range expansion differ from discontinuous introductions in that invaded and native ranges remain connected, potentially allowing pursuit of range expanding species by their natural enemies. The establishment in Britain of eight alien herbivorous gall wasps (Hymenoptera: Cynipinae) provides a rare opportunity to study continuous range expansion and natural enemy recruitment in a guild of related and ecologically similar species.

2. Four aliens (Andricus kollari, A. quercuscalicis, A. lignicolus, and A. corruptrix) reached the UK before 1990, while four more recent invaders (A. aries, A. grossulariae, A. lucidus, and Aphelonyx cerricola) reached Britain by 2000. We provide the first parasitoid records for the recent invaders, update community development for the earlier set, and use dates of first record to estimate rates of spread for all eight species.

3. While the recent invaders are restricted to southern and eastern England, three of the early invaders have reached northern Scotland. From their origins in southern England, invading gall wasps have expanded their distributions across the UK at mean rates ranging from 1.4 km/year to >20 km/year. Variation in range expansion rate was not related to life history differences, including voltinism or host oak association.

4. All species have recruited native parasitoid enemies since their arrival, and we found no evidence of pursuit by non‐native natural enemies from continental Europe. Our results suggest that over timescales predicted for rapid climate change, herbivore/parasitoid communities are unlikely to expand their range as sets of interacting species. Rather, we expect host range expansions to trigger local reassembly of communities.
Trends in incidence of oral and pharyngeal carcinoma in Florida: 1981‐2008
Authors: McGorray Susan P. , Guo Yi , Logan Henrietta
Published: September 2011

Objective: While the overall incidence rates of oral and pharyngeal squamous cell carcinoma (SCC) have decreased in the United States, there is evidence of increasing incidence at selected anatomic sites, particularly among younger adults. The objective of this study was to examine trends in incidence rates of oral and pharyngeal cancers in Florida.

Methods: Using data from the Florida Cancer Data System, we examined the incidence of oral and pharyngeal carcinomas in Florida from 1981 through 2008. Factors of interest included sex, race, and trends over time. Percent change (PC) and annual percent change (APC) were computed to characterize trends over time.

Results: A total of 53,648 cases of oral or pharyngeal cancer were identified from 1981 through 2008. Significant increasing trends were observed only for pharyngeal cancers in males, with significant decreasing trends for pharyngeal cancer in females and oral cancer for both sexes. For tonsil and base of tongue cancers, increasing trends were detected for white males only. Further investigation among white males showed that, except for base of tongue cancer in the 20‐44 age group, the incidence of both cancers increased across all age groups, with the largest increase for both sites found in the 45‐64 age group.

Conclusions: This study supports the finding of increasing incidence of SCC of the tonsil and base of tongue in males, in contrast to decreasing trends for most oral and pharyngeal carcinomas. However, we observed that this increase occurred in white males only and the most dramatic increase occurred in the 45‐64 age group.
Combined Pricing and Portfolio Option Procurement
Authors: Fu Qi , Zhou Sean X. , Chao Xiuli , Lee Chung‐Yee
Published: September 2011

In this paper, we study a single‐product periodic‐review inventory system that faces random and price‐dependent demand. The firm can purchase the product either from option contracts or from the spot market. Different option contracts are offered by a set of suppliers with a two‐part fee structure: a unit reservation cost and a unit exercising cost. The spot market price is random and its realization may affect the subsequent option contract prices. The firm decides the reservation quantity from each supplier and the product selling price at the beginning of each period and the number of options to exercise (inventory replenishment) at the end of the period to maximize the total expected profit over its planning horizon. We show that the optimal inventory replenishment policy is order‐up‐to type with a sequence of decreasing thresholds. We also investigate the optimal option‐reservation policy and the optimal pricing strategy. The optimal reservation quantities and selling price are shown to be both decreasing in the starting inventory level when demand function is additive. Building upon the analytical results, we conduct a numerical study to unveil additional managerial insights. Among other things, we quantify the values of the option contracts and dynamic pricing to the firm and show that they are more significant when the market demand becomes more volatile.
The Influence of Service Orientation on B2B e‐Service Capabilities: An Empirical Investigation
Authors: Oliveira Pedro , Roth Aleda V.
Published: September 2011

E‐Services, or the company's portfolio of service offerings available to its customers through the Internet, are an emerging area of interest to operations management. Yet little is known about the operations and capabilities needed for provision of business‐to‐business (B2B) e‐services. This paper aims to make a contribution toward closing this gap. First, we develop a new construct of B2B e‐service capability, a term that captures a generic set of five interrelated and complementary dimensions: (1) e‐service recovery, (2) e‐customization, (3) ease of navigation, (4) service portfolio comprehensiveness, and (5) information richness. These combined operational abilities are associated with B2B service delivery, including its portal design, technology architecture, and mix of product and service offerings. They are posited to be necessary for delivering effective B2B e‐services. We also argue that, both service orientation (SO) and customer receptivity to technology, influence B2B e‐service capability. We empirically test a path model using structural equation modeling on a sample of 181 businesses that have deployed B2B e‐services. We find that the influence of SO on performance is not direct but rather mediated by the e‐service capability, a finding that holds for both goods producers and service providers. We suggest that a firm's SO may mitigate industrial customers' resistance toward conducting business online.
Arterial pressure oscillations are not associated with muscle sympathetic nerve activity in individuals exposed to central hypovolaemia
Authors: Ryan Kathy L. , Rickards Caroline A. , Hinojosa‐Laborde Carmen , Cooke William H. , Convertino Victor A.
Published: September 2011

Non‐Technical Summary  The body adjusts the level of sympathetic nervous system activation to regulate blood pressure in health and disease. Therefore, knowing the level of sympathetic activation is important to treat patients with abnormal sympathetic nervous system function. Directly measuring sympathetic activation is difficult, however, and not possible in most clinical settings. Previous investigators have shown that the variability in blood pressure increases during sympathetic activation. To determine if this is a good non‐invasive index of sympathetic activation, we compared blood pressure variability to the direct measurement of sympathetic activation in healthy humans. We activated the sympathetic nervous system by redistributing blood volume away from the head and brain, which also occurs with prolonged standing or haemorrhage. We show that the relationship between variability in blood pressure and sympathetic activation is not the same in all individuals, indicating that blood pressure variability cannot be reliably used to measure sympathetic activation.
Losartan abolishes oxidative stress induced by intermittent hypoxia in humans
Authors: Pialoux Vincent , Foster Glen E. , Ahmed Sofia B. , Beaudin Andrew E. , Hanly Patrick J. , Poulin Marc J.
Published: September 2011

Non‐Technical Summary  Intermittent hypoxia is known to increase oxidative stress and decrease nitric oxide metabolism. These two responses, which are involved in hypoxia‐induced hypertension, may be mediated by angiotensin II. Using a novel human experimental model, we show that blockade of the type 1 angiotensin II receptors by a medication called losartan prevented the increase in oxidative stress and the decrease in nitric oxide metabolism induced by 6 h of intermittent hypoxia. These results show that the upregulation of angiotensin II contributes to the overproduction of free radicals associated with intermittent hypoxia and help us better understand why blood pressure increases in medical disorders associated with intermittent hypoxia, such as obstructive sleep apnoea.
The GABRA6 mutation, R46W, associated with childhood absence epilepsy, alters α6β2γ2 and α6β2δ GABAA receptor channel gating and expression
Authors: Hernandez Ciria C. , Gurba Katharine N. , Hu Ningning , Macdonald Robert L.
Published: September 2011

Non‐technical summary  Childhood absence epilepsy (CAE) is a genetic form of epilepsy that typically develops at 4–8 years of age with brief losses of consciousness and frequent staring spells. Genetic defects or mutations associated with this disorder have been found in specialized membrane proteins called GABAA receptor channels. GABAA receptors are ligand‐gated chloride channels, and the majority are thought to be composed of α, β and γ or α, β and δ subunit proteins that mediate both rapid, phasic inhibitory synaptic transmission and steady‐state, tonic perisynaptic inhibition in the nervous system. Here we showed that a novel GABAA receptor α6 subunit mutation linked with CAE, R46W, impaired gating and assembly of both αβγ and αβδ GABAA receptors. These findings suggested that the CAE‐associated α6(R46W) subunit mutation could cause neuronal disinhibition and thus increase susceptibility to generalized seizures through a reduction of αβγ and αβδ receptor function and expression.
Hourly Solar Radiation Model Suitable for Worldwide Typical Weather File Generation
Authors: Seo Donghyun , Krarti Moncef
Published: September 2011

A new model is developed to predict hourly solar radiation for any climate zone worldwide. The model solar radiation predictions are suitable to generate typical weather files used to evaluate the long-term performance of renewable energy systems and building energy systems. The predictions of the new solar model are compared as well as measured solar radiation data obtained for several weather stations located in various climate zones worldwide. It is found that the new solar model is able to estimate monthly solar radiation with a 7% prediction error for secondary stations and 2% prediction error for primary stations.
Modeling of Polarization-Specific Phonon Transmission Through Interfaces
Authors: Huang Zhen , Murthy Jayathi Y. , Fisher Timothy S.
Published: September 2011

In this work, the atomistic Green’s function method is extended to compute transmission functions for each phonon polarization. The eigenvectors and eigenvalues of the overall density of states matrices are manipulated to yield a density of states matrix for each polarization. A decomposed self-energy is calculated from the density of states matrix for each polarization and used to calculate the transmission function for a particular phonon branch. In a pure bulk material such as silicon, each transmission function exhibits a frequency-independent value of unity. In heterogeneous bulk materials, the transmission function is reduced significantly due to the junction of dissimilar materials.
Legacy Machine Monitoring Using Power Signal Analysis
Authors: Deshpande Amit , Pieper Ron
Published: September 2011

A typical manufacturing job shop comprises of legacy machine tools, new (modern) machine tools, material handling devices, and peripheral manufacturing equipments. Automated monitoring of legacy machine tools has been a long-standing issue for the manufacturing industry primarily because of the computer numeric controller (CNC) closed architecture and limited external communication functionality. This paper describes a non-invasive methodology and development of a software application to monitor real-time machine status, energy usage, and other machining parameters for a legacy machine tool using power signal analysis. State machine algorithm is implemented to detect tool changes and part count. The system architecture, implementation, benefits, limitations, and future work needed for the legacy machine tool monitoring application is explained in detail.
Study of the Mechanics of the Micro-Groove Cutting Process
Authors: Bourne Keith A. , Kapoor Shiv G. , DeVor Richard E.
Published: September 2011

In an earlier paper, a high-speed micro-groove cutting process that makes use of a flexible single-point cutting tool was presented. In this paper, 3D finite element modeling of this cutting process is used to better understand process mechanics. The development of the model, including parameter estimation and validation, is described. Validation experiments show that on average the model predicts side burr height to within 2.8%, chip curl radius to within 4.1%, and chip thickness to within 25.4%. The model is used to examine chip formation, side burr formation, exit burr formation, and the potential for delamination of a workpiece consisting of a thin film on a substrate. Side burr formation is shown to primarily occur ahead of a tool and is caused by expansion of material compressed after starting to flow around a tool rather than becoming part of a chip. Exit burr formation is shown to occur when a thin membrane of material forms ahead of a tool and splits into two side segments and one bottom segment as the tool exits a workpiece. Lastly, examination of the stresses below a workpiece surface shows that film delamination can occur when the depth of a groove cut into a thin film is large relative to the film thickness.
Rapid-Tooling of Bunched Electrode for EDM
Authors: Li Lei , Xiang Xiaoli , Gu Lin , Zhao Wansheng
Published: September 2011

A bunched electrode for Electrical Discharge Machining (EDM) is formed by bunching numerous cell electrodes as a whole and allows better flushing to facilitate removal of more heat and debris produced during machining. This paper proposes a rapid tooling method for preparing bunched electrodes with desired end-face. A specially designed apparatus, which sits on an XY worktable of a CNC machine tool, is employed to hold the pre-bunched with flat end-face. By using a protrusion pin which is fixed on Z-axis, the heights of each cell electrode are protruded one after another according to a CNC program, which is generated by CAD/CAM software. The end-face of the bunched electrode approximates the ideal end-face of the designed 3D model by adjusting the Z positions of each cell electrode. By using this method the cost and time for electrode preparation are dramatically reduced as compared to that made by traditional cutting method. An investigation on 3D cavity machining of bunched electrode was conducted. The result gives a solid verification of the feasibility of using bunched electrode into roughing process of EDM.
Preparation of Porous Metallic Nickel by Jet Electrodeposition
Authors: Shen Li-da , Tian Zong-jun , Liu Zhi-dong , Huang Yin-hui
Published: September 2011

The theory and related technology of porous metallic nickel by using jet electrodeposition (JED) are reviewed, and preparation of different porosities of the porous metallic nickel samples was made by the self-developed device. The surface morphology, microstructure, grain size of the micro-cell structure of deposition were studied and analyzed by SEM, and the mechanical properties of the sample, such as surface micro hardness and compressive property were also studied. The results are as follows: the process of porous nickel preparation by jet electrodeposition mentioned in paper is capable of preparing porous metal with dendritic crystal structure as the subject porous structure. Ejection electrodeposition has great advantages in machining efficiency and cost compared with porous metal preparation process of traditional electrodeposition. The porous nickel metal sample prepared, in respects of pore distribution and porosity, are affected by electrodeposited porous dendritic crystal layers. The formula Bath A, which has a relatively low concentration of nickel ions, can make the preparation of porous dendrite structure more favorable in the way that it has more uniform compactness. Current density is the key indicator in forming ideal branched crystal; more than 60A/dm2 can make the process access to a good working state. With the increase in current density, the dendrite formation of porous structure becomes more compact. The porosity of the prepared sample is 48.7%, using jet scanning electrodeposition with the current density at 80A/dm2. The surface micro hardness of the sample reaches HV 315. The compressive yield stress of porous Nickel is 11.35 MPa, which has a large number of plastic deformations of the absorption capacity. From original data of sample energy absorption rate and fitting curve, it is known that there comes great plastic deformation, which gives the sample better absorption ability and relatively greater energy absorption rate at a relatively low flow stress.
The Use of Hybrid System of Classification for the Retrieval and Modification of Mechanical Products
Authors: Adeoye A. O. M. , Sze´csi T.
Published: September 2011

With people becoming more individualistic in their choices they make in personalizing the goods and services they use, as resulted in major development that has been recorded in the customisation world. This individualism has resulted in the increase in demand of customized products in many industries especially in the footwear, kitchen and computer industries. However, little has been done when it comes to mechanically oriented products and little flexibility has been given to the consumers in the co-creation of customized products. The Hybrid system of classification is one way to satisfy the customers’ need for the products that are mechanically oriented in nature thereby meeting their desire needs. This paper presents a framework in which an Hybrid system of classification is used to integrates Customers into the design process by defining, configuring, matching, or modifying personal product that is mechanically oriented in nature and grouping the products into classes and sub-classes using a wide range of product parameters, products configuration which make it possible to add and/or change functionalities of a core product, a coding system for mechanical designs which is applicable to each product in the hierarchy, the use of a database for the products information. And the retrieval system to retrieve a similar product code from the database if the initial customer configuration data does not yield a feasible product code through the application of Analytic Hierarchy Process and finally modifying the existing similar product to suit the customers desire.
Research on Dry EDM Processing Performance With Two Kinds of Pulse Generator Modes
Authors: Li Liqing , Fu Yi , Song Yingjie
Published: September 2011

Dry EDM (Electrical discharge machining in gas) is an innovative electrical discharge machining (EDM) method. The machining performances of dry EDM vary from that of the liquid medium due to the different physical properties of gases and liquids. The generator, a key component in an EDM machine tool, supplies electrical energy to ionize the dielectric, therefore generator mode plays important roles in EDM performance. In this work, experiments were conducted to study the machining performances of dry EDM with two generator modes: the iso-frequencial mode and the iso-pulse mode. Experimental results show that the material removal rate (MRR) and surface roughness (SR) value using the iso-frequencial mode are higher than that of the iso-pulse mode in dry EDM and reasons for the experimental phenomena were analyzed. Under the iso-pulse mode, MRR and SR present an approximately linear increase with an increase in the pulse width increase. The iso-frequencial mode could be used in the rough machining gauge and the iso-pulse mode might be used in finish machining. It is concluded that a high frequency and narrow pulse generator with a high opening voltage might be suitable for dry EDM under a certain conditions.
The Periodical Fluctuation of Residual Stress in Hard Turned Surface and its Relationship With Chip Formation
Authors: Zhang Xueping , Wu Shenfeng , Liu C. Richard
Published: September 2011

To evaluate the residual stress distribution along cutting direction in hard turning process, an explicit dynamic thermo-mechanical orthogonal Finite Element Model (FEM) is developed to consider the correlation between residual stress distribution and chip morphology and plough effect by cutting edge. The FEM adopts Johnson-Cook (J-C) model to describe work material property, the critical equivalent plastic strain criterion to simulate chip separation behavior, and the revised coulomb’s law to capture the friction pattern between the tool and chip interface. The FEM is validated by comparing the predicted and experimental chip morphology and residual stress distribution. The residual stress distribution in hard machined surface along cutting direction is accurately captured by using sharp and honed cutting edge tools. The residual stresses by sharp tool demonstrate a periodical characteristic, the fluctuation amplitudes are determined in the surface and subsurface along the cutting direction, and the fluctuation frequency corresponds to that of the saw-tooth chip. However, the residual stresses by honed cutting edge tool demonstrate an indistinct periodic characteristic, the fluctuation frequency in surface and subsurface is larger than that of the saw-tooth chip. Saw-tooth chip formation process by sharp tool is identified to analyze the residual stress scatter periodic mechanism, which associates with the fluctuation of cutting force and temperature. The plough process by honed cutting edge tool is identified to explain the equilibrium effect on the amplitude and frequency of residual stress scatter in hard turned surface and subsurface. The periodical fluctuation characteristics of residual stress in hard turned surface and subsurface is revealed and verified by determining its amplitude and frequency corresponding to that of the saw-tooth chip. The analysis will enhance the fatigue life prediction accuracy by incorporating the effect of residual stresses periodical fluctuation on the crack initiation and propagation life in hard turned surface and subsurface.
Flow Stress Experimental Determination for Warm-Forming Process
Authors: Kong Ting Fai , Chan Luen Chow , Lee Tai Chiu
Published: September 2011

Warm forming is a manufacturing process in which a workpiece is formed into a desired shape at a temperature range between room temperature and material recrystallization temperature. Flow stress is expressed as a function of the strain, strain rate, and temperature. Based on such information, engineers can predict deformation behavior of material in the process. The majority of existing studies on flow stress mainly focus on the deformation and microstructure of alloys at temperature higher than their recrystallization temperatures or at room temperature. Not much works have been presented on flow stress at warm-forming temperatures. This study aimed to determine the flow stress of stainless steel AISI 316L and titanium TA2 using specially modified equipment. Comparing with the conventional method, the equipment developed for uniaxial compression tests has be verified to be an economical and feasible solution to accurately obtain flow stress data at warm-forming temperatures. With average strain rates of 0.01, 0.1, and 1 /s, the stainless steel was tested at degree 600, 650, 700, 750, and 800 °C and the titanium was tested at 500, 550, 600, 650, and 700 °C. Both materials softened at increasing temperatures. The overall flow stress of stainless steel was approximately 40 % more sensitive to the temperature compared to that of titanium. In order to increase the efficiency of forming process, it was suggested that the stainless steel should be formed at a higher warm-forming temperature, i.e. 800 °C. These findings are a practical reference that enables the industry to evaluate various process conditions in warm-forming without going through expensive and time consuming tests.
Machine Anomaly Detection and Diagnosis Incorporating Operational Data Applied to Feed Axis Health Monitoring
Authors: Liao Linxia , Pavel Radu
Published: September 2011

Solutions for machinery anomaly detection and diagnosis are typically designed on an ad hoc, custom basis, and previous studies have shown limited success in automating or generalizing these solutions. Reusing and maintaining the analysis software, especially when the machine usage pattern or operating condition changes, remains a challenge. This paper outlines a strategy to make use of operational data obtained from the machine’s controller and signals obtained from external sensors to provide an accurate analysis within each operating condition. Operational data collected from the controller is used both for labeling datasets into different operating conditions and for analysis. Principal component analysis (PCA) is adopted to identify critical sensors that can provide useful information. Self-organizing map (SOM)-based anomaly detection and diagnosis methods are used to automatically convert data to easily understandable machine health information for operators. Experiment trials conducted on a feed-axis test-bed demonstrated the effectiveness of incorporating operational data for anomaly detection and diagnosis.