bluuebunny/crossref_metadata_2025 huggingface dataset:
Context‐dependent IL‐6 potentiation of interferon‐ gamma‐induced IL‐12 secretion and CD40 expression in murine microglia
Authors: Lin Hsiao‐Wen , Levison Steven W.
Published: August 2009

Interleukin‐6 (IL‐6) is produced by neurons, astrocytes, and microglia, and elevated levels of IL‐6 within the CNS have been documented in multiple neurological disorders including Alzheimer’s disease, stroke, epilepsy, attention deficit disorder, cerebral palsy, and multiple sclerosis. Here, we sought to understand how IL‐6 regulates microglial signal transduction and their immune properties. Using highly enriched cultures of neonatal murine microglia we show that IL‐6 alone has direct effects on microglia as it activates STAT3 and extracellular signal‐regulated kinase pathways in a time‐ and dose‐dependent fashion and it enhances interferon‐gamma (IFNγ)‐stimulated IL‐12 secretion. However, other immune properties were only weakly modulated by IL‐6 when administered without the soluble IL‐6 receptor (sIL‐6R). For instance, IFNγ‐induced expression of the co‐stimulatory molecule, CD40 was dependent on sIL‐6R administration. IL‐6 with or without sIL‐6R did not affect major histocompatability complex class II expression. In granulocyte–macrophage colony‐stimulating factor (GMCSF)‐induced dendritic cell‐like microglia, IL‐6/sIL‐6R and IFNγ stimulated an even greater increase in CD40 expression compared with primary microglia. Altogether, our results demonstrate that microglial responses to IL‐6 are not simple in that the effects of IL‐6 are context‐dependent. In particular, the presence or absence of sIL‐6R, IFNγ or GMCSF will alter the type and amplitude of their response.
Cationic amino acid transporter 1‐mediated l‐arginine transport at the inner blood–retinal barrier
Authors: Tomi Masatoshi , Kitade Naohisa , Hirose Shirou , Yokota Noriko , Akanuma Shin‐ichi , Tachikawa Masanori , Hosoya Ken‐ichi
Published: August 2009

The purpose of this study was to identify the transporter mediating l‐arginine transport at the inner blood–retinal barrier (BRB). The apparent uptake clearance of [3H]l‐arginine into the rat retina was found to be 118 μL/(min·g retina), supporting a carrier‐mediated influx transport of l‐arginine at the BRB. [3H]l‐Arginine uptake by a conditionally immortalized rat retinal capillary endothelial cell line (TR‐iBRB2 cells), used as an in vitro model of the inner BRB, was primarily an Na+‐independent and saturable process with Michaelis‐Menten constants of 11.2 μM and 530 μM. This process was inhibited by rat cationic amino acid transporter (CAT) 1‐specific small interfering RNA as well as substrates of CATs, l‐arginine, l‐lysine, and l‐ornithine. The expression of cationic amino acid transporter (CAT) 1 mRNA was 25.9‐ and 796‐fold greater than that of CAT3 in TR‐iBRB2 and magnetically isolated rat retinal vascular endothelial cells, respectively. The expression of CAT1 protein was detected in TR‐iBRB2 cells and immunostaining of CAT1 was observed along the rat retinal capillaries. In conclusion, CAT1 is localized in retinal capillary endothelial cells and at least in part mediates l‐arginine transport at the inner BRB. This process seems to be closely involved in visual functions by supplying precursors of biologically important molecules like nitric oxide in the neural retina.
Long‐term prognostic role of coronary flow velocity reserve in patients with aortic valve stenosis – insights from the SZEGED Study
Authors: Nemes Attila , Balázs Erika , Csanády Miklós , Forster Tamás
Published: August 2009

Introduction:  Coronary flow velocity reserve (CFR) is markedly reduced in severe aortic valve stenosis (AS). Independent prognostic value of pulsed‐wave Doppler echocardiography‐derived CFR was seen in a variety of diseases. However, the prognostic significance of CFR by pulsed‐wave Doppler echocardiography has never been evaluated in patients with AS.

Methods:  A total of 49 AS patients (mean age: 63 ± 9 years, 26 men) were enrolled in this prospective follow‐up study; they all had undergone standard transthoracic Doppler‐echo study, coronary angiography and dipyridamole stress transoesophageal echocardiography as CFR measurement.

Results:  During a mean follow‐up of 82 ± 38 months, 18 patients suffered cardiovascular death and one patient had non‐fatal stroke. Other two patients underwent reoperation of dysfunctional prosthetic aortic valve. Using receiver operator curve (ROC) analysis, CFR <2·13 had the highest accuracy in predicting cardiovascular outcome (sensitivity 90%, specificity 46%, area under the curve 66%, P = 0·02). By univariable analysis, diabetes mellitus, hypertension, presence of coronary artery disease and lower CFR were significant predictors of cardiovascular morbidity and mortality. Multivariable regression analysis showed that only lower CFR [hazard ratio (HR) 1·67, 95% CI of HR: 1·05–4·29, P < 0·05] was independent predictor of cardiovascular outcome.

Discussion:  Long‐term prognostic significance of CFR for prediction of cardiovascular morbidity and mortality has been demonstrated during a 9‐year follow‐up in patients with AS. Despite a relatively small number of patients were followed, CFR was found to be an independent predictor for future cardiovascular events in AS patients.
Comparative geometric and radiometric evaluation of mobile phone and still video cameras
Authors: Akca Devrim , Gruen Armin
Published: August 2009

This paper examines the potential of mobile phones to be used as front‐end sensors for photogrammetric procedures and applications. For this purpose, two mobile phone cameras (Sony Ericsson K750i and Nokia N93) were calibrated over an indoor 3D testfield, using a self‐calibrating bundle adjustment. Geometric accuracy tests were carried out in order to evaluate their metric performances and to compare the results with respect to two off‐the‐shelf digital still video cameras (Sony DSC W100 and Sony DSC F828). The geometric accuracy evaluation comprised an absolute accuracy test, JPEG test and temporal stability test. The radiometric capabilities of all cameras (except that the DSC W100 was replaced with a DSC T100 camera) were also evaluated and compared by carrying out modulation transfer function (MTF) analysis, image noise analysis and an operating range test. Substantial systematic errors were diagnosed in some systems. However, with proper calibration it is believed that these devices can be used for many photogrammetric tasks.
Implementation of ISBT 128 in China
Authors: Kong Changhong , Meng Zhonghua , Lv Hangjun , Yan Lixing , Zheng Xiaofan
Published: August 2009

BACKGROUND: In 2001, the blood collection agencies of Zhejiang Province adopted a unified information system, but when a blood product was transferred from the collection and processing facility inventory to some other inventories, because of lacking the unique identifying ability between facilities, the numbers might be overlapped. The exchange of blood units between agencies needed change of labels, and it was very complicated. The SARS outbreak in 2003 made this problem more prominent. Therefore, we decided to redevelop a new information system based on ISBT 128 to solve this problem.

STUDY DESIGN AND METHODS: We registered with ICCBBA and obtained the technical documentation and database. We requested the new product description code from ICCBBA and properly adjusted the incompatibility between ISBT 128 and the national standards. We redesigned the information system and labels and validated some related equipment and the laboratory information system.

RESULTS: In May 2005, we completed the development of the new information system based on ISBT 128, and by the end of 2005, all the blood collection agencies of the Zhejiang Province began to use ISBT 128. As a result, the product information in blood collection agencies of Zhejiang Province can be shared, and the exchange of blood products between agencies became safe and rapid. It was highly praised by the nation's Ministry of Health.

CONCLUSIONS: ISBT 128 was successfully implemented in Zhejiang Province.
Solutions to the Asset Allocation Problem by Informed Respondents: The Significance of the Size‐of‐Bet and the 1/N Heuristic
Authors: Clark Gordon L. , Caerlewy‐Smith Emiko , Marshall John C.
Published: August 2009

Abstract

Asset allocation is a classic topic in the theory of finance and a crucial issue for investment policy. Noted for its significance in driving pension fund performance, it is also an issue that individual investors consider when designing their investment portfolios. In theory, Markowitz and those following in his wake have an optimal solution. In practice, however, we show that when asked to allocate their own money to a set of asset classes (from relatively low risk to high risk) in an experimental situation, most of our informed respondents would vary their investment strategies according to the size‐of‐bet (the money value of assets to be invested). We also show that most participants in the study adopted one of three solutions to the posed problem only one of which could be thought consistent with Benartzi and Thaler's 1/n heuristic. Since respondent solutions do not seem to be explained by formal education, professional qualifications, or training, it is suggested that solutions to the asset allocation problem are a product of strategies that mix intuitive responses to the initial tranche of money with theoretical cum practical shared conventions. Solutions to the asset allocation puzzle suggest that the size‐of‐bet could be a significant consideration for many informed investors. In conclusion, suggestions are made about taking forward closer scrutiny of these experimental results.
A Case with Catecholaminergic Polymorphic Ventricular Tachycardia Unmasked after Successful Ablation of Atrial Tachycardias from Pulmonary Veins
Authors: SUGIYASU AIKO , OGINOSAWA YASUSHI , NOGAMI AKIHIKO , HATA YOSHITO
Published: August 2009

Catecholaminergic polymorphic ventricular tachycardia (VT) is characterized by polymorphic VT during exercise, and the association of atrial fibrillation (AF) has been reported. However, the mechanism of AF in this disease and the relationship between VT and AF has been obscured. We described a 13‐year‐old girl who referred for catheter ablation of exercise‐induced paroxysmal AF. Multifocal atrial tachycardia mimicking AF on the surface electrocardiogram originated from multiple pulmonary veins (PVs). While AT became non‐inducible after the isolation of four PVs, polymorphic VT was initiated by isoproterenol infusion. Polymorphic VT was suppressed during rapid atrial pacing.
The importance of interannual variation and bottom–up nitrogen enrichment for plant–pollinator networks
Authors: Burkle Laura , Irwin Rebecca
Published: August 2009

Striking changes in food web structure occur with alterations in resource supply. Like predator–prey interactions, many mutualisms are also consumer–resource interactions. However, no studies have explored how the structure of plant–pollinator networks may be affected by nutrient enrichment. For three years, we enriched plots of subalpine plant communities with nitrogen and observed subsequent effects on plant–pollinator network structure. Although nitrogen enrichment affects floral abundance and rates of pollinator visitation, we found no effects of nitrogen enrichment on the core group of generalist plants and pollinators or on plant–pollinator network structure parameters, such as network topology (the identity and frequency of interactions) and the degree of nestedness. However, individual plant and pollinator taxa were packed into the nested networks differently among nitrogen treatments. In particular, pollinators visited different numbers and types of plants in the nested networks, suggesting weak, widespread effects of nitrogen addition on individual taxa. Independent of nitrogen enrichment, there were large interannual differences in network structure and interactions, due to species turnover among years and flexibility in interacting with new partners. These data suggest that the community structure of small‐scale mutualistic networks may be relatively robust to short‐term bottom–up changes in the resource supply, but sensitive to variation in the opportunistic behavior and turnover of plant and pollinator species among years.
‘Biological restoration’: total crown anterior
Authors: Tavano Karine Taís Aguiar , Botelho Adriana Maria , Motta Thiago Peixoto , Paes Thalita Mara Oliveira
Published: August 2009

Abstract –  Restorative odontology is in constant evolution and is constantly seeking more aesthetic solutions to attend to demands from patients in search of the perfect smile. The case study presented herein refers to the aesthetic and functional recuperation of dental element 21, through the use of a dental fragment obtained through an extracted tooth, a technique known as ‘Biological Restoration’. The results obtained, which were highly satisfactory, lead one to conclude that this technique can be considered as an alternative to all others and can be carried out successfully, quickly, and inexpensively.
pH changes in external root surface cavities after calcium hydroxide is placed at 1, 3 and 5 mm short of the radiographic apex
Authors: Chamberlain Thaddeus M. , Kirkpatrick Timothy C. , Rutledge Richard E.
Published: August 2009

Abstract –  The purpose of this study was to test the null hypothesis that there is no difference in the pH on the external apical dentin surface when the canal is completely filled with calcium hydroxide or when it is placed 3 or 5 mm short of the apical foramen in extracted human teeth. The root canals of single‐rooted anterior human teeth were cleaned and shaped after decoronation. Cavities about 0.50 mm deep and 1.0 mm wide located at 1, 3 and 5 mm from the radiographic apex were prepared on the external root surface and the teeth were randomly divided into four groups. The roots were filled with calcium hydroxide at 1, 3 and 5 mm from the radiographic apex, and the control group was left empty. pH readings were obtained at intervals over a 28‐day study. The roots which were filled within 1 mm of the radiographic apex had the greatest increase in pH in each of the cavities. These results demonstrate that the greatest pH change on the external root surface near the apex is obtained when the canal is more completely filled with calcium hydroxide.
The Place of Knowledge and Evidence in the Context of Australian General Practice Nursing
Authors: Mills Jane , Field John , Cant Robyn
Published: August 2009

Background: The purpose of the study was to ascertain the place of knowledge and evidence in the context of Australian general practice nursing. General practice nursing is a rapidly developing area of specialized nursing in Australia. The provision of primary care services in Australia rests largely with medical general practitioners who employ nurses in a small business model.

Methods: A statistical research design was used that included a validated instrument: the developing evidence‐based practice questionnaire (Gerrish et al. 2007). A total of 1,800 Victorian practice nurses were surveyed with a return of 590 completed questionnaires, equaling a response rate of 33%.

Findings: Lack of time to access knowledge for practice was a barrier for participants in this study. In‐service education and training opportunities were ranked as the number one source of knowledge for general practice nurses. Experiential learning and interactions with clients, peers, medical practitioners, and specialist nurses were also considered very important sources of knowledge. Research journals were ranked much lower than experiential learning and personal interactions. Participants assessed their own skills at sourcing and translating evidence into practice knowledge as low. Younger general practice nurses were more likely than older nurses to assess themselves as competent at using the library and Internet to locate evidence.

Discussion: The predominantly oral culture of nursing needs to be identified and incorporated into methods for disseminating evidence from research findings in order to increase the knowledge base of Australian general practice nurses.

Conclusions: Findings from this study will be significant for policy makers and funders of Australian nursing in general practice. The establishment of a career structure for general practice nurses that includes salaried positions for clinical nurse specialists would assist in the translation of evidence into knowledge for utilization at the point of care.
The Changing Roles of Thai Buddhist Women: Obscuring Identities and Increasing Charisma1
Authors: Seeger Martin
Published: August 2009

Thai Buddhism is characterised by a complex polymorphism that has become manifest in the plurality of religious movements and cults. There exists an enormous variety of belief systems and religious practices that are based on widely differing interpretations of religious texts or other sources of normative and formative authority. These systems and practices are far from static, but changing with a similar pace as current Thai society as a whole does. This religious plurality and change can also readily be perceived in the socio‐religious roles of Thai Buddhist women. With this paper, I intend to contribute to the existing body of academic literature on the changing roles of Thai Buddhist women, by reporting on the lives of a sample of outstanding Buddhist women, who excel in various realms. While doing so, I will show the significance of their lives and work in the context of current Thai Buddhism.
Antibacterial Interactions of Monolaurin with Commonly Used Antimicrobials and Food Components
Authors: Zhang Hui , Wei Hewen , Cui Yinan , Zhao Guoqun , Feng Fengqin
Published: August 2009

ABSTRACT:  Monolaurin is a nontraditional antimicrobial agent that possesses better antimicrobial activities but causes no health problems to consumers, but the use of monolaurin in the food industry as a preservative is still limited. Using a microtiter plate assay, the minimum inhibitory concentrations for monolaurin were 25 μg/mL against Escherichia coli, 12.5 μg/mL against Staphylococcus aureus, and 30 μg/mL against Bacillus subtilis. The interaction with commonly used antimicrobials revealed that monolaurin and nisin acted synergistically against the test microorganisms, monolaurin in combination with sodium dehydroacetate or ethylenediaminetetraacetic acid was synergistic against E. coli and B. subtilis but not S. aureus, and monolaurin combined with calcium propionate or sodium lactate showed no synergistic effects against any test microorganism. The interaction with food components revealed that the antibacterial effectiveness of monolaurin was reduced by fat or starch while the monolaurin activity remained unchanged in the presence of protein. This study contributes to a better understanding on the use of monolaurin as a nontraditional preservative in food products. Results from this study suggest the potential use of monolaurin as a nontraditional preservative in combination with commonly used antimicrobials, such as nisin, sodium dehydroacetate, or ethylenediaminetetraacetic acid, and suggest that the antibacterial effectiveness of monolaurin may be reduced significantly in high‐fat or low‐starch food products.
Pacific Hake (Merluccius Productus) Hydrolysates as Cryoprotective Agents in Frozen Pacific Cod Fillet Mince
Authors: Cheung Imelda W.Y. , Liceaga Andrea M. , Li‐Chan Eunice C.Y.
Published: August 2009

ABSTRACT:  Fish protein hydrolysates produced by proteolysis of Pacific hake (Merluccius productus) with Alcalase® (FPH‐A) or Flavourzyme® (FPH‐F) were investigated as a potential alternative to the 1 : 1 blend of sucrose–sorbitol (SuSo) commonly used for cryoprotection of frozen fish mince. The physicochemical properties of cod mince samples in the absence (control) or presence of 8% FPH‐A, FPH‐F, or SuSo were evaluated before and after 6 freeze–thaw cycles, with differences noted at the 5% significance level. Freeze–thawing of control sample increased expressible moisture (from 22% to 33%) and cook loss (from 3% to 16%). These poor water retention properties were improved in samples containing FPH or SuSo. Differential scanning calorimetry showed higher proportion of unfrozen water in freeze–thawed samples containing FPH‐F or FPH‐A (0.36 g/g) compared to SuSo (0.33 g/g) and control (0.24 g/g) samples. Textural analysis of cooked mince from unfrozen samples indicated greater hardness for FPH than SuSo and control samples, while freeze–thawing resulted in decreased hardness for FPH and SuSo samples. Content and surface hydrophobicity of extractable natural actomyosin (NAM) were maintained after freeze–thawing of samples containing FPH‐F or SuSo, compared to 50% decrease in extractable NAM and a significant increase in surface hydrophobicity for the control. The presence of oligopeptides in both hydrolysates and the high levels of free amino acids including Asp, Glu, Arg, and Lys in FPH‐F might be responsible for their cryoprotective action. This study provides strong evidence to support development of FPH as a new generation cryoprotectant to maintain quality of frozen fish.
Immunomodulatory Properties of Fermented Soy and Dairy Milks Prepared with Lactic Acid Bacteria
Authors: Wagar L.E. , Champagne C.P. , Buckley N.D. , Raymond Y. , Green‐Johnson J.M.
Published: August 2009

ABSTRACT:  Fermented soy and dairy milk preparations provide a means for delivering lactic acid bacteria and their fermentation products into the diet. Our aims were to test immunomodulatory bioactivity of fermented soy beverage (SB) and dairy milk blend (MB) preparations on human intestinal epithelial cells (IEC) and to determine the impact of freezing medium on culture survival prior to bioactivity analyses. Fermented SB and MB were prepared using pure or mixed cultures of Streptococcus thermophilus ST5, Bifidobacterium longum R0175, and Lactobacillus helveticus R0052. Immunomodulatory bioactivity was assessed by testing selected SB and MB ferments on tumor necrosis factor α (TNFα)‐treated IEC and measuring effects on Interleukin‐8 (IL‐8) production. Impact of timing of ferment administration relative to this pro‐inflammatory challenge was investigated. The most pronounced reductions in IEC IL‐8 production were observed when IEC were treated with either SB or MB ferment preparations prior to TNFα challenge. These results indicate that freezing‐stable MB and SB ferments prepared with selected strains can modulate IEC IL‐8 production in vitro, and suggest that yogurt‐like fermented soy formulations could provide a functional food alternative to milk‐based fermented products.
Biological ‘glue’ and ‘Velcro’: molecular tools for adhesion and biofilm formation in the hairy and gluey bug Pseudomonas aeruginosa
Authors: Giraud Caroline , Bernard Christophe , Ruer Ségolène , De Bentzmann Sophie
Published: August 2009

Pseudomonas aeruginosa contains an extraordinarily large number of loci encoding systems facilitating a communal lifestyle and binding to supports of various natures. These P. aeruginosa systems are reviewed here and may be categorized as classical or non‐classical systems. They highlight the panoply of strategies that this hairy and gluey bacterium has developed for dealing with the diverse environments with which it is faced during various types of infection, involving complex regulatory networks that have not yet been fully elucidated but several aspects of which are discussed here.
Substantial high‐affinity methanotroph populations in Andisols effect high rates of atmospheric methane oxidation
Authors: Maxfield Pete J. , Hornibrook Ed R.C. , Evershed Richard P.
Published: August 2009

Methanotrophic bacteria in soils derived from volcanic ash (Andisols) were characterized via time series 13C‐phospholipid fatty acid (PLFA) labelling. Three Andisols were incubated under 2 ppmv 13CH4 for up to 18 weeks, thus enabling high‐affinity methanotrophs to be selectively characterized and quantified. PLFA profiles from all soils were broadly similar, but the magnitude of the high‐affinity methanotrophic populations determined through 13C‐PLFA‐stable isotope probing displayed sizeable differences. Substantial incorporation of 13C indicated very large high‐affinity methanotrophic populations in two of the soils. Such high values are far in excess (10×) of those observed for a range of mineral soils incubated under similar conditions (Bull et al., 2000; Maxfield et al., 2006; 2008a, b). Two of the three Andisols studied also displayed high but variable CH4 oxidation rates ranging from 0.03 to 1.58 nmol CH4 g−1 d.wt. h−1. These findings suggest that Andisols, a previously unstudied soil class with respect to high‐affinity methanotrophic bacteria, may oxidize significant amounts of atmospheric methane despite their low areal coverage globally.
Ulnohumeral Arthroplasty in the Management of the Arthritic Elbow
Authors: Hearnden Anthony , Talwalkar Sumedh C. , Roy Niloy , Kimani Mwaura , Hayton Michael J. , Trail Ian A. , Stanley John K.
Published: August 2009

Background

Osteoarthritis of the elbow is a difficult problem to treat. The results of total joint arthroplasty have historically been poor.

Methods

Seventy-nine patients who underwent ulnohumeral arthroplasty between 1994 and 2002 were included in the study. Fifty-nine elbows in 58 patients were available for clinical assessment. There were 14 females and 44 males with an average age of 63 years (32 to 80) and a mean follow-up of 7.8 years (5 to 12). There were 39 (67%) patients with primary osteoarthritis, 18 (31%) with post-traumatic and 1 patient with post-septic arthritis of the elbow.

Results

Using the visual analogue scale (VAS) (0 to 10), the pain score was seen to improve from 8 (6 to 10) to 3.8 (0 to 9). Twenty six patients (44%) were on minimal or no analgesia. The arc regarding flexion/extension was found to increase by 18°. Twenty-four percent of patients suffered an adverse incident. Radiologically 28 (6%) patients had recurrent bone formation in the olecranon fossa. This however did not correspond to the clinical outcome. Patients with loose bodies seemed to do better in the post-operative phase.

Conclusion

Ulnohumeral arthroplasty has a role in the management of the arthritic elbow as it provides pain relief in the post-operative period. However the improvement in the range of movement is limited particularly with regard to the arc of extension. This improvement in pain appears to diminish with time.
The Cardiac Biomarker NT‐proBNP Is Increased in Dogs with Azotemia
Authors: Raffan E. , Loureiro J. , Dukes‐McEwan J. , Fonfara S. , James R. , Swift S. , Bexfield N. , Herrtage M.E. , Archer J.
Published: August 2009

Background: Amino‐terminal probrain natriuretic peptide (NT‐proBNP) has been proposed as a useful biomarker for heart disease in dogs. In humans, decreased glomerular filtration rate (GFR) increases NT‐proBNP.

Objective: To investigate whether decreased GFR as indicated by plasma creatinine concentration is associated with increased NT‐proBNP in dogs without heart disease.

Animals: Four groups of dogs: healthy (n= 39), azotemic (n= 36), heart disease (n= 37), and congestive heart failure (CHF) (n= 7) presented to 2 teaching hospitals.

Methods: Prospective observational cohort study. Plasma creatinine concentration and NT‐proBNP were measured in every dog. Nonparametric tests were used to compare the differences among groups. The median and actual results for each group were compared with the manufacturer's recommended and previously published suggestions for cut‐off values for diagnosis of heart disease.

Results: Median (range) plasma creatinine concentration was 1.47 (1.06–1.70), 4.36 (1.74–15.6), 1.22 (0.69–1.91), and 1.45 (0.63–1.64) mg/dL and median (range) NT‐proBNP was 118 (2–673), 556 (37–1,819), 929 (212–5,658), and 3,144 (432–5,500) pmol/L for the healthy, azotemic, heart disease, and CHF groups, respectively. Pair‐wise comparison indicated a significant difference among all groups for NT‐proBNP (P≤ .049). Plasma creatinine concentration was significantly higher in the azotemic group compared with other groups (P < .001) but there was no significant among other groups. Application of 3 recommended cut‐off values led to misclassification of dogs with azotemia as having heart disease.

Conclusions: Azotemia results in NT‐proBNP being increased to concentrations reported as diagnostic of heart disease or heart failure in dogs. Care should be employed when interpreting the results of NT‐proBNP in patients with known or possible increased plasma creatinine concentration.
Urinary Corticoid : Creatinine Ratios in Dogs with Pituitary‐Dependent Hypercortisolism during Trilostane Treatment
Authors: Galac S. , Buijtels J.J.C.W.M. , Kooistra H.S.
Published: August 2009

Background:The adrenocorticotropic hormone (ACTH) stimulation test is used to evaluate trilostane treatment in dogs with hypercortisolism.

Hypothesis:The urinary corticoid : creatinine ratio (UCCR) is a good alternative to the ACTH stimulation test to determine optimal trilostane dose.

Animals:Eighteen dogs with pituitary‐dependent hypercortisolism.

Methods:In this prospective study, the dose of trilostane was judged to be optimal on the basis of resolution of clinical signs of hypercortisolism and results of an ACTH stimulation test. The owners collected urine for determination of UCCR at 2‐week intervals for at least 8 weeks after achieving the optimal trilostane dose.

Results:The UCCRs were significantly higher before treatment (11.5–202.0 × 10−6; median, 42.0 × 10−6) than at rechecks 2 months after optimal dosing, but they did not decrease below the upper limit of the reference range in the majority of dogs. The UCCRs of 11 dogs that initially were dosed insufficiently (range, 7.5–79.0 × 10−6; median, 31.0 × 10−6) did not differ significantly from UCCRs when the dosage was optimal (8.2–72.0 × 10−6; median, 33.0 × 10−6). Post‐ACTH cortisol concentrations did not correlate significantly with UCCRs at rechecks during trilostane treatment. Long‐term follow‐up indicated that the decrease in UCCR below the upper limit of the reference was associated with hypocortisolism.

Conclusion and Clinical Importance:The UCCR cannot be used as an alternative to the ACTH stimulation test to determine the optimal dose of trilostane, but might be helpful in detecting dogs at risk for developing hypocortisolism during trilostane treatment.
Foreign Language Reading Comprehension Test: L1 versus L2 in Open‐Ended Questions
Authors: Godev Concepción B. , Martínez‐Gibson Elizabeth A. , Toris Carol C. M.
Published: August 2009

Abstract: This article addresses the issue of using students' native language (L1) versus second language (L2) in testing instruments for reading comprehension in the L2 classroom. Four groups of students of third‐semester, college‐level Spanish were tested under four different conditions involving combinations of L1 and L2. The test consisted of a reading passage in L2 and seven open‐ended questions. The results suggest that open‐ended reading comprehension tests may be better assessment instruments if some of the questions are phrased in the L1 and test takers are given the opportunity to respond in the L1.
Predicting the Distribution of Combustion Timing Ensemble in an HCCI Engine
Authors: Shahbakhti Mahdi , Ghazimirsaied Ahmad , Koch Charles Robert
Published: August 2009

Control of Homogeneous Charge Compression Ignition (HCCI) engines to obtain the desirable operation requires understanding of how different charge variables influence the cyclic variations in HCCI combustion. Combustion timing for consecutive cycles at each operating point makes an ensemble of combustion timing which can exhibit different shapes of probability distributions depending on the random and physical patterns existing in the data. In this paper, a combined physical-statistical control-oriented model is developed to predict the distribution of HCCI combustion timing (CA50, crank angle of 50% fuel mass fraction burnt) for a range of operating conditions. The statistical model is based on the Generalized Extreme Value (GEV) distribution and the physical model embodies a modified knock integral model, a fuel burn rate model, a semi-empirical model for the gas exchange process and an empirical model to estimate the combustion timing dispersion. The resulting model is parameterized for the combustion of Primary Reference Fuel (PRF) blends using over 5000 simulations from a detailed thermo-kinetic model. Empirical correlations in the model are parameterized using the experimental data obtained from a single-cylinder engine. Once the model is parameterized it only needs five inputs: intake pressure, intake temperature, Exhaust Gas Recirculation (EGR) rate, equivalence ratio and engine speed. The main outputs of the model are CA50 and the Probability Density Function (PDF) metrics of CA50 distribution. Experimental CA50 is compared with predicted CA50 from the model and the results show a total average error of less than 1.5 degrees of crank angle for 213 steady-state operating points with four different PRF fuels at diversified operating conditions. Predicted PDF of the CA50 ensemble is compared with that of the experiments for PRF fuels at different running conditions. The results indicate a good agreement between simulation and the experiment.
Experimental and Simulation Study of Fuel Injection Timing, Pressure and EGR for Lower Exhaust Emissions From Diesel HCCI Combustion
Authors: Juttu S. , Thipse S. S. , Marathe N. V. , Gajendra Babu M. K.
Published: August 2009

The objective of this work is to study the effect of different control parameters viz. EGR, fuel injection pressure and start of injection timing on exhaust emissions from diesel fueled HCCI combustion concept. A 4-cylinder LCV engine has been selected for experiments and FIRE 3D CFD software was used for simulation study. The basic idea of the simulation study is to find the suitable EGR ratio to run the engine on HCCI combustion mode so as to avoid any damage to the engine during testing. From simulation study, it was observed that the minimum EGR required for running the engine at 5.6 bar BMEP @ 2500 rpm in HCCI mode is approximately 45%. The trends of simulation results viz. soot and NOx emissions are closely following the experiments. The experiments were conducted at different loads at 2500 rpm and EGR varied from 0% to 60%. With increased EGR ratio, soot bump was observed at 50%, 75% and 100%. The BTE dropped to 24.5% from 33.5%. The effect of fuel injection pressures (750bar, 1000bar and 1500bar) were studied to improve the BTE and to control soot bump over a wide range injection timings EGR ratio. Detailed experiments were conducted at 2.8 bar BMEP @ 2500 rpm to study simultaneous reduction of NOx, SOOT, UHC and CO emissions from diesel HCCI combustion. At injection pressure (1500 bar), advanced fuel injection timing and high EGR ratio, the soot CO and THC emissions were reduced significantly without penalty on NOx emissions. The BTE was improved from 24.5% to 31% against 33.5% of convention diesel combustion.
Air Separation Membranes: An Alternative to EGR in Large Bore Natural Gas Engines
Authors: Biruduganti Munidhar , Gupta Sreenath , Bihari Bipin , McConnell Steve , Sekar Raj
Published: August 2009

Air Separation Membranes (ASM) could potentially replace Exhaust Gas Recirculation (EGR) technology in engines due to the proven benefits in NOx reduction but without the drawbacks of EGR. Previous investigations of Nitrogen Enriched Air (NEA) combustion using nitrogen bottles showed up to 70% NOx reduction with modest 2% nitrogen enrichment. The investigation in this paper was performed with an ASM capable of delivering at least 3.5% NEA to a single cylinder spark ignited natural gas engine. Low Temperature Combustion (LTC) is one of the pathways to meet the mandatory ultra low NOx emissions levels set by regulatory agencies. In this study, a comparative assessment is made between natural gas combustion in standard air and 2% NEA. Enrichment beyond this level degraded engine performance in terms of power density, Brake Thermal Efficiency (BTE), and unburned hydrocarbon (UHC) emissions for a given equivalence ratio. The ignition timing was optimized to yield maximum brake torque for standard air and NEA. Subsequently, conventional spark ignition (SI) was replaced by laser ignition (LI) to extend lean ignition limit. Both ignition systems were studied under a wide operating range from ψ: 1.0 to the lean misfire limit. It was observed that with 2% NEA, for a similar fuel quantity, the equivalence ratio (Ψ) increases by 0.1 relative to standard air conditions. Analysis showed that lean burn operation along with NEA and alternative ignition source such as LI could pave the pathway for realizing lower NOx emissions with a slight penalty in BTE.
Turbocharged CNG Engines for Urban Transportation: Evaluation of Turbolag Reduction Strategies by Means of Computational Analyses
Authors: Baratta Mirko , Spessa Ezio
Published: August 2009

Nowadays, many urban buses for public transportation are fuelled by compressed natural gas (CNG), due to its potential for energy saving and pollutant reduction, with specific reference to particulate matter emissions. However, turbocharging is required to recover the gaseous-fuel related power gap with respect to more traditional engines running on liquid fuels. Therefore, turbolag reduction is fundamental to achieve high performance during engine transients. Significant support for the study of turbocharged CNG engines and guidelines for the turbomatching process can be provided by 1D numerical simulation tools. In this paper, the topic of turbolag reduction is analyzed, and different strategies, namely, Early-Exhaust Valve Opening-Variable Valve Actuation (E-EVO-VVA) and spark timing control for combustion retard (ComR), are analyzed by means of a specifically developed and calibrated GT-POWER® engine model. Tip-in maneuvers in which the engine was coupled to a torque hydraulic converter under stall conditions were investigated, so as to reproduce a typical load transient condition for an urban bus accelerating from engine idle. The best improvement of turbolag was obtained by combining E-EVO-VVA and ComR, with a reduction of turbolag ranging from 60% to 70%. When a limit on the incylinder pressure is introduced, in order to prevent excessive exhaust valve mechanical stresses, the higher achievable reduction in turbolag was found to be between 35% and 45%.
Understanding the Fundamentals of Piston Ring Axial Motion and Twist and the Effects on Blow-By
Authors: Mittler Richard , Mierbach Albin , Richardson Dan
Published: August 2009

Advances in modern engine development are becoming more and more challenging. The intense increase of thermal and mechanical loads interacting in the combustion chamber as a result of higher power density requires perfecting the function of piston rings especially with regard to emission reduction technology. The major obstacle to predicting blow-by and oil consumption is the behavior of the piston rings under engine operating conditions. Design and functionality of a piston ring are highly influenced by the operating conditions. To understand the fundamentals of ring behavior and in this way the effects on blow-by and oil consumption, an analytical tool has been developed to transform the physical boundary conditions of engine kinematics and ring design into a reliable simulation. This paper describes the physical basics of ring movement under dynamic loading conditions and gives an overview of the results. It also was necessary to validate the model with real engine measurements to understand the fundamentals of ring design as a function of the described mathematics.
Multidimensional Modeling of Natural Gas Jet and Mixture Formation in DI SI Engines: Development and Validation of a Virtual Injector Model
Authors: Baratta Mirko , Catania Andrea E. , Pesce Francesco C.
Published: August 2009

During the last years, the integration of computational CFD tools in the internal combustion (IC) engine design process has continuously been increased, allowing to save time and cost as the need of experimental prototypes has diminished. Numerical analyses of IC engine flows are rather complex from both the conceptual and operational sides. In fact, such flows involve a variety of unsteady phenomena, and the right balance between numerical solution accuracy and computational cost should be always reached. The present paper is focused on computational modeling of natural gas (NG) direct injection (DI) processes from a poppet-valve injector into a bowl-shaped combustion chamber. At high injection pressures, the efflux of gas from the injector and the mixture formation processes include compressible and turbulent flow features, such as rarefaction waves and shock formation, which are difficult to be accurately captured by the numerical simulation, particularly when combustion chamber geometry is complex and piston and intake/exhaust valve grids are moving. A three-dimensional moving grid model of the combustion engine chamber, originally developed by the authors, was enhanced by increasing the accuracy in the sonic section proximity of the critical valve seat nozzle, in order to precisely capture the expansion dynamics the methane undergoes inside the injector and immediately downstream from it. The enhanced numerical model was validated by comparing numerical results to Schlieren experimental images for nitrogen injection into a constant-volume bomb. Then, numerical studies were carried out in order to characterize the fuel jet properties and the evolution of mixture-formation for a centrally-mounted injector configuration in both cases of a pancake test chamber and the real-shaped engine chamber. Finally, the fluid properties computed by the model in the throat-section of the critical nozzle were taken as reference data for developing a new effective ‘virtual injector’ model, which allows the designer to remove the whole computational domain upstream from the sonic section of the nozzle, keeping the flow properties practically unchanged. The outcomes of such a virtual injector model were shown to be in very good agreement with the results of the enhanced complete injector model, confirming the reliability of the proposed novel approach.
An Experimental Investigation of the Exhaust Emissions From Spark-Assisted Homogeneous Charge Compression Ignition in a Single-Cylinder Research Engine
Authors: Keros P. E. , Zigler B. T. , Wiswall J. T. , Walton S. M. , Wooldridge M. S.
Published: August 2009

The present study investigates the potential impact of spark-assisted (SA) homogeneous charge compression ignition (HCCI) on pollutant exhaust gas emissions from an internal combustion engine. A single-cylinder research engine was used to compare the exhaust emissions of the engine when operated in HCCI, SA-HCCI and conventional spark ignited modes of operation. The study builds on previous results demonstrating the effects of the spark plasma kernel on the ignition process [1, 2]. Specifically, this study investigates the NOx, CO, and HC emissions from an optical engine fueled with indolene in HCCI and SA-HCCI modes at fuel lean conditions. Fuel/air equivalence ratios ranged from φ = 0.3–0.6. Time-averaged emissions were measured using an exhaust gas analyzer. In-cylinder pressure data were also acquired. The results show NOx emissions follow the trends of peak in-cylinder pressure implying that thermal NOx mechanisms dominate both the HCCI and SA-HCCI modes of engine operation. For SA-HCCI, spark timing could be used to change ignition phasing, and consequently change the in-cylinder peak pressure and resulting NOx emissions. Comparing HCCI and SA-HCCI emissions at nominally similar conditions (specifically, comparable indicated mean effective pressures and equivalence ratios) yielded similar NOx emissions. These data show that SA-HCCI may not have a NOx penalty when the spark timing is carefully applied.
A Statistical Approach to Spark Advance Mapping
Authors: Corti Enrico , Forte Claudio
Published: August 2009

Engines performance and efficiency are largely influenced by the combustion phasing. Operating conditions and control settings influence the combustion development over the crankshaft angle: the most effective control parameter used by Electronic Control Units (ECU) to optimize the combustion process for Spark Ignition (SI) engines is Spark Advance (SA). SA mapping is a time-consuming process, usually carried out with the engine running in steady state on the test bench, changing SA values while monitoring Brake and Indicated Mean Effective Pressure (BMEP, IMEP) and Brake Specific Fuel Consumption (BSFC). Mean values of IMEP and BSFC for a test carried out with a given SA setting are considered as the parameters to optimize. However, the effect of SA on IMEP and BSFC is not deterministic, due to the cycle-to-cycle variation: the analysis of mean values requires many engine cycles to be significant of the performance obtained with the given control setting. Finally other elements, such as engine or components ageing, and disturbances like Air-to-Fuel Ratio (AFR) or air, water and oil temperature variations, could affect the tests results: this facet can be very significant for racing engines testing. This paper presents a novel approach to SA mapping, with the objective of improving the performance analysis robustness, while reducing the test time. The methodology is based on the observation that, for a given running condition, IMEP can be considered a function of the combustion phasing, represented by the 50% Mass Fraction Burned (MFB50) parameter. Due to cycle-to-cycle variation, many different MFB50 and IMEP values are obtained during a steady state test carried out with constant SA. While MFB50 and IMEP absolute values are influenced by disturbance factors, the relationship between them holds, and it can be synthesized by means of the angular coefficient of the tangent line to the MFB50-IMEP distribution. The angular coefficient variations as a function of SA can be used to feed a SA controller, able to maintain the optimal combustion phasing. Similarly, knock detection is approached by evaluating two indexes: the distribution of a typical knock-sensitive parameter (MAPO, Maximum Amplitude of Pressure Oscillations) is related to that of CHRNET (net Cumulative Heat Release), determining a robust knock index. A knock limiter controller can then be added, in order to restrict the SA range to safe values. The methodology can be implemented in real-time combustion controllers: the algorithms have been applied offline to sampled data, showing the feasibility of fast and robust automatic mapping procedures.
Exhaust Emissions From a Stoichiometric, Ammonia and Gasoline Dual Fueled Spark Ignition Engine
Authors: Grannell Shawn M. , Assanis Dennis N. , Gillespie Donald E. , Bohac Stanislav V.
Published: August 2009

Engine-out and post-catalyst emissions of ammonia, hydrocarbons, nitric oxide, carbon monoxide, and nitrous oxide are measured for an ammonia and gasoline dual fueled spark ignition engine. An ordinary three-way catalytic converter can be used to clean up these emissions. The clean-up region occurs between stoichiometric and 0.2% rich. Ordinary exhaust gas oxygen sensors are usable with ammonia and gasoline in much the same way as they are with gasoline alone.
Dynamic Modeling and Control of an Hybrid Electric Powertrain for Simulation Under Transient Conditions
Authors: Crosnier Ronan , Hetet Jean-Franc¸ois
Published: August 2009

This article presents a causal, forward looking approach for the hybrid electric vehicle where the typical performance engine map representation has been modified. The need for a more physical model of the power stroke process has been fulfilled with “the filling and emptying” method. The thermodynamic states in the intake and exhaust systems are calculated, while the in-cylinder process is still based on the engine fuel consumption map as a calibrated data. Comparisons with the conventional model are established, most important is the response of the engine torque under the load demand. This notion of an “available” torque is taken into account by the energy management strategy. Changes on the distribution of energy flow in order to meet the required torque at the wheel are observed and influence of this modelisation on the fuel consumption over various driving cycles is evaluated.