bluuebunny/crossref_metadata_2025 huggingface dataset:
Serpentine polymorphs andP-Tevolution of metaperidotites and serpentinites in the Takab area, NW Iran
Authors: Hajialioghli R. , Moazzen M. , Droop G. T. R. , Oberhänsli R. , Bousquet R. , Jahangiri A. , Ziemann M.
Published: September 2007

The Takab meta-ultramafic rocks of northwestern Iran crop out in association with a variety of metamorphic rocks and they can be divided into three types on the basis of dominant mineral assemblage and degree of serpentinization: metaperidotites, talc-serpentine rocks and serpentinites. The peridotite protoliths were mainly spinel-harzburgites and -dunites. The talc-serpentine rocks formed under low-grade conditions and their dominant mineral assemblage is lizardite/chrysotile + talc + calcite/dolomite. Pseudomorphic textures after olivine and pyroxene are typical. Later, lower amphibolite-facies metamorphism produced antigorite, clinochlore and tremolite. Late alteration, assisted by local shearing, produced more antigorite and late lizardite in the metaperidotites. The mineral chemistry of the serpentine polymorphs is variable. Compositions of coexisting spinel and olivine point to an ophiolitic origin. Thermometric estimates from co-existing relict olivine, pyroxenes and spinel are in the range 1000–1200ºC; clinopyroxene barometry yields a pressure of 24± 2.7 kbar for the mantle conditions. Exhumation and hydration followed, and the stability of lizardite/chrysotile constrains the T and XCO2to <280ºC and <0.002, respectively. Subsequent prograde regional metamorphism took place in an orogenic setting, reaching peak temperatures in the range 410–540ºC at XCO2>0.1. A Neoproterozoic–Early Cambrian age for the Takab protoliths is suggested on the basis of correlations with the Central Iran Zone. The strips of ultramafic rock in the Takab complex can be attributed to lithospheric remnants of the Proto-Tethyan ocean which closed during the Pan-African orogeny.
IL-15 regulates immature B-cell homing in an Ly49D-, IL-12–, and IL-18–dependent manner
Authors: Hart Gili , Avin-Wittenberg Tamar , Shachar Idit
Published: September 2007

To complete their maturation and participate in the humoral immune response, immature B cells that leave the bone marrow are targeted to specific areas in the spleen, where they differentiate into mature cells. Previously, we showed that immature B cells actively down-regulate their integrin-mediated migration to lymph nodes or to sites of inflammation, enabling their targeting to the spleen for final maturation. This inhibition is mediated by IFN-γ, which is transcribed and secreted at low levels by these immature B cells; IFN-γ expression is extinguished following B-cell maturation. Stimulation of the MHC class I receptor, Ly49D, triggers a signaling cascade that increases transcription of both IL-12 (p40) and IL-18; these, in turn, induce the secretion of IFN-γ. In the present study, we demonstrate that Ly49D-dependent secretion of IL-12 and IL-18 induces IL-15 expression by immature B cells, and that these 3 factors together regulate IFN-γ production that inhibits their ability to home to the lymph nodes or to sites of inflammation. Thus, IL-15 controls immature B-cell homing, resulting in shaping the B-cell repertoire to enable an efficient immune response.
Recent major improvement in long-term survival of younger patients with multiple myeloma
Authors: Brenner Hermann , Gondos Adam , Pulte Dianne
Published: September 2007

In the past, most patients with multiple myeloma (MM) died within 5 to 10 years after diagnosis. Within the past decade, several new therapeutic interventions have been introduced, including autologous stem-cell transplantation, thalidomide, lenalidomide, and bortezomib. We estimated trends in age-specific 5- and 10-year relative survival of patients with MM in the United States from 1990-1992 to 2002-2004 from the 1973-2004 database of the Surveillance, Epidemiology, and End Results (SEER) Program. Techniques of period analysis were used to show most recent developments. Overall, 5-year relative survival increased from 28.8% to 34.7% (P < .001), and 10-year relative survival increased from 11.1% to 17.4% (P < .001) between 1990-1992 and 2002-2004. Much stronger increases were seen in the age group younger than 50 years, leading to 5- and 10-year relative survival of 56.7% and 41.3% in 2002-2004, and in the age group 50 to 59 years, leading to 5- and 10-year relative survival of 48.2% and 28.6% in 200-2004. By contrast, only moderate improvement was seen in the age group 60 to 69 years, and essentially no improvement was achieved among older patients. Our period analysis discloses a major increase in long-term survival of younger patients with MM in recent years, which most likely reflects the effect of recent advances in therapy and their dissemination in clinical practice.
Invasive pulmonary aspergillosis in patients with chronic obstructive pulmonary disease
Authors: Bulpa P. , Dive A. , Sibille Y.
Published: September 2007

Aspergillus spp. cultured in specimens from the airways of chronic obstructive pulmonary disease (COPD) patients are frequently considered as a contaminant. However, growing evidence suggests that severe COPD patients are at higher risk of developing invasive pulmonary aspergillosis (IPA), although IPA incidence in this population is poorly documented. Some data report that COPD is the underlying disease in 1% of patients with IPA.

Definitive diagnosis of IPA in COPD patients is often difficult as tissue samples are rarely obtained before death. Diagnosis is therefore usually based on a combination of clinical features, radiological findings (mostly thoracic computed tomography scans), microbiological results and, sometimes, serological information.

Of 56 patients with IPA reported in the literature, 43 (77%) were receiving corticosteroids on admission to hospital. Breathlessness was always a feature of disease and excess wheezing was present in 79% of patients. Fever (>38°C) was present in only 38.5%. Chest pain and haemoptysis were uncommon. Six out of 33 (18%) patients had tracheobronchitis observed during bronchoscopy. The median delay between symptoms and diagnosis was 8.5 days. The mortality rate was high: 53 out of 56 (95%) patients died despite invasive ventilation and antifungal treatment in 43 (77%) of them.

In chronic obstructive pulmonary disease patients, invasive pulmonary aspergillosis currently carries a very poor prognosis. Outcome could perhaps be improved by more rapid diagnosis and prompt therapy with voriconazole.
Bronchoalveolar lavage, sputum and exhaled clinically relevant inflammatory markers: values in healthy adults
Authors: Balbi B. , Pignatti P. , Corradi M. , Baiardi P. , Bianchi L. , Brunetti G. , Radaeli A. , Moscato G. , Mutti A. , Spanevello A. , Malerba M.
Published: September 2007

Bronchoalveolar lavage (BAL), induced sputum and exhaled breath markers (exhaled nitric oxide and exhaled breath condensate) can each provide biological insights into the pathogenesis of respiratory disorders. Some of their biomarkers are also employed in the clinical management of patients with various respiratory diseases. In the clinical context, however, defining normal values and cut-off points is crucial. The aim of the present review is to investigate to what extent the issue of defining normal values in healthy adults has been pursued for the biomarkers with clinical value.

The current authors reviewed data from literature that specifically addressed the issue of normal values from healthy adults for the four methodologies.

Most studies have been performed for BAL (n = 9), sputum (n = 3) and nitric oxide (n = 3). There are no published studies for breath condensate, none of whose markers yet has clinical value. In healthy adult nonsmokers the cut-off points (mean+2sd) for biomarkers with clinical value were as follows. BAL: 16.7% lymphocytes, 2.3% neutrophils and 1.9% eosinophils; sputum: 7.7×106·mL−1total cell count and 2.2% eosinophils; nitric oxide: 20.2 ppb.

The methodologies differ concerning the quantity and characteristics of available reference data. Studies focusing on obtaining reference values from healthy individuals are still required, more evidently for the new, noninvasive methodologies.
A Latent Variable Approach for Meta-Analysis of Gene Expression Data from Multiple Microarray Experiments
Authors: Choi Hyungwon , Shen Ronglai , Chinnaiyan Arul M , Ghosh Debashis
Published: September 2007

Background

With the explosion in data generated using microarray technology by different investigators working on similar experiments, it is of interest to combine results across multiple studies.

Results

In this article, we describe a general probabilistic framework for combining high-throughput genomic data from several related microarray experiments using mixture models. A key feature of the model is the use of latent variables that represent quantities that can be combined across diverse platforms. We consider two methods for estimation of an index termed the probability of expression (POE). The first, reported in previous work by the authors, involves Markov Chain Monte Carlo (MCMC) techniques. The second method is a faster algorithm based on the expectation-maximization (EM) algorithm. The methods are illustrated with application to a meta-analysis of datasets for metastatic cancer.

Conclusion

The statistical methods described in the paper are available as an R package, metaArray 1.8.1, which is at Bioconductor, whose URL ishttp://www.bioconductor.org/.
Flow cytometric probing of mitochondrial function in equine peripheral blood mononuclear cells
Authors: Cassart Dominique , Fett Thomas , Sarlet Michaël , Baise Etienne , Coignoul Freddy , Desmecht Daniel
Published: September 2007

Background

The morphopathological picture of a subset of equine myopathies is compatible with a primary mitochondrial disease, but functional confirmation in vivo is still pending. The cationic dye JC-1 exhibits potential-dependent accumulation in mitochondria that is detectable by a fluorescence shift from green to orange. As a consequence, mitochondrial membrane potential can be optically measured by the orange/green fluorescence intensity ratio. A flow cytometric standardized analytic procedure of the mitochondrial function of equine peripheral blood mononuclear cells is proposed along with a critical appraisal of the crucial questions of technical aspects, reproducibility, effect of time elapsed between blood sampling and laboratory processing and reference values.

Results

The JC-1-associated fluorescence orange and green values and their ratio were proved to be stable over time, independent of age and sex and hypersensitive to intoxication with a mitochondrial potential dissipator. Unless time elapsed between blood sampling and laboratory processing does not exceed 5 hours, the values retrieved remain stable. Reference values for clinically normal horses are given.

Conclusion

Whenever a quantitative measurement of mitochondrial function in a horse is desired, blood samples should be taken in sodium citrate tubes and kept at room temperature for a maximum of 5 hours before the laboratory procedure detailed here is started. The hope is that this new test may help in confirming, studying and preventing equine myopathies that are currently imputed to mitochondrial dysfunction.
Institutional racism in psychiatry: lessons from inquiries
Authors: Singh Swaran P.
Published: September 2007

‘While everyone is entitled to their own opinions, they are not entitled to their own facts' (attributed to Daniel Patrick Moynihan). The President of the Royal College of Psychiatrists recently reiterated the College's determination to tackle institutional racism in psychiatry, as defined in the MacPherson Report (MacPherson, 1999). This reaction was prompted by a paper suggesting that racism was perhaps not the only explanation for ethnic differences in rates of psychosis and detention under the Mental Health Act 1983 (Singh & Burns, 2006). Although not providing a scientific criticism of the BMJ paper or any evidence to the contrary, the President stated that the paper risked setting ‘psychiatry back by 20 years’ (Hollins & Moodley 2006).
Outcome of acute psychiatric in-patient care where there are no crisis or home treatment teams
Authors: Shajahan Polash , Taylor Mark
Published: September 2007

Aims and Method

To examine the pathways and outcomes of in-patient care in our locality before crisis teams were introduced details of all emergency referrals to psychiatry were recorded and all admissions to hospital were assessed within 24 h of admission and discharge.

Results

Over a 6-month period, 88% (n=1852) of calls to the duty psychiatrist occurred between 09.00 and 01.00 h. Referrals from accident and emergency and general practice represented the majority of calls (80%); 40% of patients were admitted. Highest admission rates were for patients who were psychotic, suicidal or depressed. Admission led to improvement in all symptoms.

Clinical Implications

In-patient care is a valuable resource for stabilising patients who are acutely ill. Routine monitoring of unscheduled activity can inform service delivery.
Human Epidermal Growth Factor Receptor 2 Status Correlates With Lymph Node Involvement in Patients With Estrogen Receptor (ER) –Negative, but With Grade in Those With ER-Positive Early-Stage Breast Cancer Suitable for Cytotoxic Chemotherapy
Authors: Bartlett John M.S. , Ellis Ian O. , Dowsett Mitch , Mallon Elizabeth A. , Cameron David A. , Johnston Stephen , Hall Emma , A'Hern Roger , Peckitt Clare , Bliss Judith M. , Johnson Lindsay , Barrett-Lee Peter , Ellis Paul
Published: September 2007

Purpose

Human epidermal growth factor receptor 2 (HER-2) expression is associated with increased risk of high-grade disease, nodal metastasis, and absence of estrogen receptors (ERs) in early breast cancer. We tested interactions between ER and HER-2 to determine if they may modulate breast cancer nodal metastasis and proliferation.

Patients and Methods

Tumors from the Cancer Research UK Taxotere as Adjuvant Chemotherapy phase III trial were tested for HER-2 using current diagnostic procedures. ER status, progesterone status, clinicopathologic characteristics, and patient age were included in a logistic regression analysis to identify associations with HER-2 status (positive v negative).

Results

A total of 841 (23.6%) of 3,565 samples were HER-2 positive (3+ by immunohistochemistry or positive by fluorescent in situ hybridization). ER-negative tumors were more likely to be HER-2 positive than were ER-positive tumors (odds ratio [OR] = 1.87, ER negative v ER positive; P < .001). For ER-positive tumors, risk of HER-2 positivity increased by grade (OR = 7.6, grade 3 v grade 1; P < .001) but not nodal status (OR = 1.3, four or more positive nodes v node negative; P = .08). Conversely, ER negative node-positive tumors were markedly more frequently HER-2 positive than node-negative cases (OR = 3.05, four or more positive nodes v node negative; P < .001) but independent of grade (OR = 0.82, grade 3 v grade 1; P = .76).

Conclusion

In early breast cancer patients selected for cytotoxic chemotherapy, we identified significant interactions between HER-2 and ER expression that correlate with tumor pathology. In ER-positive breast cancers, HER-2 expression correlates with grade, not nodal metastasis. In ER-negative breast cancers, HER-2 expression correlates with increased nodal positivity, not grade. ER and HER-2 expression may modify tumor pathology via ER/HER-2–mediated cross talk.
Incidence of Metastatic Nonseminomatous Germ Cell Tumor Outside the Boundaries of a Modified Postchemotherapy Retroperitoneal Lymph Node Dissection
Authors: Carver Brett S. , Shayegan Bobby , Eggener Scott , Stasi Jason , Motzer Robert J. , Bosl George J. , Sheinfeld Joel
Published: September 2007

Introduction

Modified template retroperitoneal lymph node dissections (RPLND) have become increasing applied in the postchemotherapy (PC) setting. We evaluated our experience with PC-RPLND to determine the incidence of disease extending outside the boundaries of a modified PC-RPLND.

Patients and Methods

From 1989 through 2003, a total of 532 men underwent PC-RPLND for metastatic nonseminomatous germ cell tumor (NSGCT). Of these, 269 (51%) had either viable germ cell tumor (GCT) or teratoma present in the RPLND specimen. After Institutional Review Board approval, clinical and pathologic data were obtained from our prospective surgical database. The incidence of retroperitoneal disease outside the boundaries of five modified templates was reported for the presence of viable GCT or teratoma.

Results

Of the 269 patients with viable GCT or teratoma, 20 to 86 (7% to 32%) patients had evidence of extratemplate retroperitoneal disease, depending on the boundaries of the modified template. There was no difference in the histologic distribution for patients with disease confined to or outside of the modified templates. Despite the absence of preoperative radiographic evidence of disease outside the boundaries of the Testicular Tumor Study Group template, the incidence of extratemplate metastasis for men with residual retroperitoneal masses less than 1, 1 to 2, 2 to 5, and more than 5 cm was two of 24 (8%), seven of 38 (18%), 27 of 92 (29%), and 14 of 55 (25%), respectively.

Conclusion

Our data suggest a bilateral RPLND is a prudent approach for the management of men with metastatic NSGCT after chemotherapy, given that at least 7% to 32% of men will have teratoma or viable GCT outside the boundaries of a modified template.
Minireview: Entrainment of the Suprachiasmatic Clockwork in Diurnal and Nocturnal Mammals
Authors: Challet Etienne
Published: September 2007

Daily rhythmicity, including timing of wakefulness and hormone secretion, is mainly controlled by a master clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN clockwork involves various clock genes, with specific temporal patterns of expression that are similar in nocturnal and diurnal species (e.g. the clock gene Per1 in the SCN peaks at midday in both categories). Timing of sensitivity to light is roughly similar, during nighttime, in diurnal and nocturnal species. Molecular mechanisms of photic resetting are also comparable in both species categories. By contrast, in animals housed in constant light, exposure to darkness can reset the SCN clock, mostly during the resting period, i.e. at opposite circadian times between diurnal and nocturnal species. Nonphotic stimuli, such as scheduled voluntary exercise, food shortage, exogenous melatonin, or serotonergic receptor activation, are also capable of shifting the master clock and/or modulating photic synchronization. Comparison between day- and night-active species allows classifications of nonphotic cues in two, arousal-independent and arousal-dependent, families of factors. Arousal-independent factors, such as melatonin (always secreted during nighttime, independently of daily activity pattern) or γ-aminobutyric acid (GABA), have shifting effects at the same circadian times in both nocturnal and diurnal rodents. By contrast, arousal-dependent factors, such as serotonin (its cerebral levels follow activity pattern), induce phase shifts only during resting and have opposite modulating effects on photic resetting between diurnal and nocturnal species. Contrary to light and arousal-independent nonphotic cues, arousal-dependent nonphotic stimuli provide synchronizing feedback signals to the SCN clock in circadian antiphase between nocturnal and diurnal animals.
Differential Bonding Interactions of Inverse Agonists of Angiotensin II Type 1 Receptor in Stabilizing the Inactive State
Authors: Miura Shin-ichiro , Kiya Yoshihiro , Kanazawa Takanori , Imaizumi Satoshi , Fujino Masahiro , Matsuo Yoshino , Karnik Sadashiva S. , Saku Keijiro
Published: September 2007

Although the sartan family of angiotensin II type 1 (AT1) receptor blockers (ARBs), which includes valsartan, olmesartan, and losartan, have a common pharmacophore structure, their effectiveness in therapy differs. Although their efficacy may be related to their binding strength, this notion has changed with a better understanding of the molecular mechanism. Therefore, we hypothesized that each ARB differs with regard to its molecular interactions with AT1 receptor in inducing inverse agonism. Interactions between valsartan and residues Ser105, Ser109, and Lys199 were important for binding. Valsartan is a strong inverse agonist of constitutive inositol phosphate production by the wild-type and N111G mutant receptors. Substituted cysteine accessibility mapping studies indicated that valsartan, but not losartan, which has only weak inverse agonism, may stabilize the N111G receptor in an inactive state upon binding. In addition, the inverse agonism by valsatan was mostly abolished with S105A/S109A/K199Q substitutions in the N111G background. Molecular modeling suggested that Ser109 and Lys199 bind to phenyl and tetrazole groups of valsartan, respectively. Ser105 is a candidate for binding to the carboxyl group of valsartan. Thus, the most critical interaction for inducing inverse agonism involves transmembrane (TM) V (Lys199) of AT1 receptor although its inverse agonist potency is comparable to olmesartan, which bonds with TM III (Tyr113) and TM VI (His256). These results provide new insights into improving ARBs and development of new G protein-coupled receptor antagonists.
Formulation and in-vivo evaluation of l-cysteine chewing gums for binding carcinogenic acetaldehyde in the saliva during smoking
Authors: Kartal Alma , Hietala Jaana , Laakso Into , Kaihovaara Pertti , Salaspuro Ville , Säkkinen Mia , Salaspuro Mikko , Marvola Martti
Published: September 2007

Cigarette smoke contains toxic amounts of acetaldehyde that dissolves in saliva, posing a significant risk of developing oral, laryngeal and pharyngeal carcinomas. l-Cysteine, a non-essential amino acid, can react covalently with carcinogenic acetaldehyde to form a stable, non-toxic 2-methylthiazolidine-4-carboxylic acid. The main aim of this study was to find out whether it is possible to develop a chewing gum formulation that would contain cysteine in amounts sufficient to bind all the acetaldehyde dissolved in saliva during the smoking of one cigarette. The main variables in the development process were: (1) chemical form of cysteine (l-cysteine or l-cysteine hydrochloride), (2) the amount of the active ingredient in a gum and (3) manufacturing procedure (traditional or novel compression method). Saliva samples were taken over 2.5 minutes before smoking and since smoking was started for 2.5 minutes periods for 10 minutes. During a five minutes smoking period with a placebo chewing gum, acetaldehyde levels increased from 0 to 150–185 μm. Once smoking was stopped, the acetaldehyde levels quickly fell to levels clearly below the in-vitro mutagenic level of 50 μm. All chewing gums containing cysteine could bind almost the whole of the acetaldehyde in the saliva during smoking. However, elimination of saliva acetaldehyde during smoking does not make smoking completely harmless. Cysteine as a free base would be somewhat better than cysteine hydrochloride due to its slower dissolution rate. Both traditional and direct compression methods to prepare chewing gums can be utilized and the dose of l-cysteine required is very low (5 mg).
Carvedilol increases ciclosporin bioavailability by inhibiting P-glycoprotein-mediated transport
Authors: Amioka Katsuo , Kuzuya Takafumi , Kushihara Hideyuki , Ejiri Masayuki , Nitta Atsumi , Nabeshima Toshitaka
Published: September 2007

Carvedilol is often used to treat hypertension and for prophylaxis in vascular sclerosis in renal transplant recipients, who require concomitant treatment with ciclosporin. However, there are few reports regarding the pharmacokinetic interactions between carvedilol and ciclosporin. We have investigated the potential effects of carvedilol on the pharmacokinetics of ciclosporin, and examined the inhibitory effects of carvedilol on P-glycoprotein-mediated transcellular transport using Caco2 cells. Ciclosporin alone or with carvedilol was orally or intravenously administered to rats. The oral administration of carvedilol (10 mgkg−1) with ciclosporin (10 mgkg−1) increased the whole blood concentration of ciclosporin. When ciclosporin (3 mgkg−1) was intravenously administered with carvedilol (3 mgkg−1), there was no difference in the whole blood ciclosporin concentration between administration with and without carvedilol. Co-administration with carvedilol increased ciclosporin bioavailability from 33% to 70%. In Caco2 cells, carvedilol caused a concentration-dependent increase in the intracellular accumulation of ciclosporin, and its effect was comparable with that of verapamil. Carvedilol considerably raised the concentration of ciclosporin in the blood and this interaction was associated with the absorption phase of ciclosporin. This interaction was caused by the inhibition of P-glycoprotein-mediated transport by carvedilol in the intestine.
Gastroprotective activity of the hydroalcoholic extract obtained fromPolygala paniculateL. in rats
Authors: Lapa Fernanda da Rocha , Freitas Cristina Setim , Baggio Cristiane Hatsuko , Missau Fabiana Cristina , Pizzolatti Moacir Geraldo , Santos Adair R S , Marques Maria Consuelo A
Published: September 2007

The possible gastroprotective effects of the hydroalcoholic extract of Polygala paniculata in rats have been evaluated. We have investigated the effects of this hydroalcoholic extract on acute lesions induced by ethanol (70%, p.o.) and indometacin (20 mg kg−1, s.c). Its influence on mucus secretion was investigated, measured as the amount of Alcian blue dye estimated by colorimetry, and antisecretory effects were assessed in the pylorus ligature model. The treatment of rats with a crude hydroalcoholic extract of P. paniculata (HEPP; 30, 100, 300 mg kg−1, p.o., or 3, 10 and 30 mg kg−1, i.p.) decreased the ulcer index, and maintained the gastric mucus production in acute gastric lesions caused by ethanol 70%. In addition, the extract partially protected the mucosa against indometacin-induced lesions. The extract did not change the volume and acidity of gastric secretion in the pylorus-ligated rat. An additional antioxidant activity of the extract and its isolated flavonoid compound rutin, in the DPPH free radical scavenging assay, was observed. In conclusion, HEPP exhibited marked gastroprotection; these effects may have involved prostaglandins and be related to cytoprotective factors, such as antioxidant activity and maintenance of mucus production.
Antispasmodic activity of licochalcone A, a species-specific ingredient of Glycyrrhiza inflata roots
Authors: Nagai Hidemasa , He Ju-Xiu , Tani Tadato , Akao Teruaki
Published: September 2007

Licochalcone A, a species-specific and characteristic retrochalcone ingredient of Glycyrrhiza inflata root, has been shown to possess multiple bioactive properties. However, its muscle relaxant activity has not been reported previously. Licochalcone A showed a concentration-dependent relaxant effect on the contraction induced by carbachol (50% effective concentration (EC50) = 5.64 ± 1.61 μm). KCl (EC50 5.12 ± 1.68 μm), BaCl2 (EC50 1.97 ± 0.48 μm) and A23187 (EC50 2.63 ± 2.05 μm). Pretreatment with licochalcone A enhanced the relaxant effect of forskolin, an adenylyl cyclase activator, on the contraction in a similar manner to 3-isobutyl-1-methylxanthine (IBMX), a phosphodiesterase (PDE) inhibitor. Furthermore, the IC50 (22.1 ± 10.9 μm) of licochalcone A against cAMP PDE was similar to that of IBMX (26.2 ± 7.4 μm). These results indicated that licochalcone A may have been responsible for the relaxant activity of G. inflata root and acted through the inhibition of cAMP PDE.
A multiscale topography analysis of ground stainless steel and titanium alloys
Authors: Giljean S , Bigerelle M , Anselme K
Published: September 2007

This study aims to perform a multiscale analysis of abraded surfaces of 316L austenitic stainless steel and titanium alloys (TiAl6V4) grinded at different paper grades. The authors propose to answer the following question: For a given distribution of silicon carbide grains of the paper, what is the best roughness parameter and at which scale must it be evaluated better to discriminate the effect of the mechanical properties of the materials? Paper grades from 80 to 4000 were used under identical pressure and erosion time. It can be concluded that the values of the amplitude roughness parameters depend on the observation scale. It is outlined that the abrasion process is very reproducible. A statistical analysis is then proposed, first, to define a classification of the relevance of the roughness parameters for each grain size distribution, and second, to determine at which scale the mechanical properties of the bulk are more influenced for all paper grades. Finally, at relevant scales, the Abbott amplitude parameters roughness kernel (RK) is the best parameter to discriminate the paper grade effect. The mean distance between asperities (SM) is the preferred method for determining the wear effect on materials and the linear mean normalizing autocorrelation (AMNLN) is the preferred method for determining the interaction between paper grade and materials.
Effects of workpiece thermal properties on machining-induced residual stresses - thermal softening and conductivity
Authors: Nasr M , Ng E-G , Elbestawi M
Published: September 2007

Workpiece material properties play a key role in controlling the cutting process, and consequently residual stresses. Different materials may behave totally differently under the same cutting conditions; they may produce different types of chip, surface finish, residual stress, etc. The current work examines the effects of two workpiece thermal properties, specifically thermal conductivity ( k) and thermal softening exponent ( m), on machining-induced residual stresses, in order to understand their role in controlling the residual stresses induced in different materials, when cut using the same cutting conditions. Finite element analysis was used to model the process of orthogonal dry cutting, using the arbitrary-Lagrangian-Eulerian technique, and then predict the induced residual stresses. In order to isolate the effects of the examined properties ( k and m), only one material (stainless steel AISI 316L) was used as the base workpiece material, and different values were assigned to its k and m, one at a time. Values up to four times the original magnitudes were used, covering almost all commercial steels and stainless steels. All other material properties and cutting conditions were kept constant. Surface tensile residual stresses were induced in all cases, and a strong effect was found for both properties, k has mainly affected the thickness of the tensile layer, where higher k resulted in thicker layers; it has also induced higher surface tensile residual stresses. On the other hand, higher m (lower softening effects) has significantly increased the magnitude of surface tensile residual stresses, with almost no effect on the thickness of the tensile layer.
Development of automotive tubular driveshaft using the rotary swaging process
Authors: Lim S-J , Na K-H , Choi H-J , Park Y-B , Lee C-H
Published: September 2007

The present study has been carried out to investigate the driving performance characteristics for the vibration and torsional strength of the automotive tubular driveshaft manufactured by a rotary swaging process. A maximum torque and a total number of torsional repetitions for the tubular driveshaft is measured to know the respective strengths through the static torsion test and torsional endurance test. The weight of the tubular driveshaft product is reduced by about 12.8 per cent over that of the solid driveshaft with the same performance. The stiffness of the tubular driveshaft is greater than that of the solid driveshaft because the natural frequency of the tubular driveshaft is higher by about 21 per cent than that of the solid driveshaft in the experiment. The total number of the torsional repetitions up to the fracture for the tubular driveshaft is greater than 250 000. From these results, the tubular driveshaft has been proven to be more useful in many aspects such as weight reduction and improvement of vibration and stiffness characteristics compared to the solid driveshaft.
A chemically informed, control-oriented model of a three-way catalytic converter
Authors: Soumelidis M I , Stobart R K , Jackson R A
Published: September 2007

Chemical activity inside a three-way catalytic converter (TWC) is highly complex and usually is not taken into account when developing TWC control-oriented models. Such models still remain to a large extent empirical and do not perform satisfactorily under a wider range of operating conditions. This work demonstrates how a very simple model, based on the basic chemical processes that take place inside the catalytic converter, can successfully capture a large part of the strongly non-linear TWC dynamic behaviour. The proposed model is based on the reactions of ceria oxidation and carbon monoxide oxidation, which appear to dominate the fast dynamics of oxygen storage and release respectively. In addition, the water-gas shift reaction is incorporated into the model, which is responsible for the slower dynamic response of the catalyst under rich operating conditions. With some mild assumptions, a discrete-time version of the model was implemented in MATLAB. The model is sufficiently simple in structure for in-vehicle use and can be used for control and on-board diagnostic purposes.
Variable compression ratio engine: A future power plant for automobiles - an overview
Authors: Shaik Amjad , Moorthi N Shenbaga Vinayaga , Rudramoorthy R
Published: September 2007

Increasingly stringent emissions and fuel economy standards have long remained a source of challenges for research in automobile engine technology development towards the more thermally efficient and less polluting engine. Spark ignition (SI) engines have lower part-load efficiency when compared with the diesel engines. The greatest opportunity for improving SI engine efficiency is by way of higher compression ratio, variable valve timing, low friction, reducing throttling losses, boosting, and down-sizing. Variable compression ratio (VCR) technology has long been recognized as a method for improving the fuel economy of SI engines. In order to vary the compression ratio, some method of varying the geometric compression ratio through changing the clearance volume is required. There are several ways of doing this; various patents have been filed and designs presented, including modification of the compression ratio by moving the cylinder head, variation of combustion chamber volume using a secondary piston or valve, variation of piston deck height, modification of connecting rod geometry, moving the crankpin within the crankshaft, and moving the crankshaft axis. The potential of these technologies needs to be evaluated by a trade-off between cost and consumption benefit. This paper reviews the geometric approaches and solutions used to achieve VCR, considers the results of prior research, and forecasts what benefits, if any, a VCR would bring to present engine design.
A lumped-parameter model to investigate the effect of plantar pressure on arterial blood flow in a diabetic foot
Authors: Hahn C , Mahajan A , Chu T , Schoen M
Published: September 2007

This paper presents a lumped-parameter model for the big-toe region that investigates the effect of plantar pressure on the diameter of the blood vessels, specifically the arteries, in the presence of arterial and/or tissue changes. The model developed in this paper uses a multi-domain energy system approach to develop the lumped-parameter differential equations. Blood flow is modelled as fluidic flow through compliant pipes that have inertia, stiffness, and damping. The tissue material is treated as a soft compliant material that transmits the external force to the blood vessels. Conclusions have been drawn to show the effect of plantar pressure, tissue damage, and their combination on the diameter of the blood vessels. The principles used here can be used to model the entire foot and the model used to investigate the effect of plantar pressure, tissue damage, and arterial changes on different parts of the foot. The work presented here may also have applications in other vascular diseases.
Preclinical assessment of the long-term endurance of cemented hip stems. Part 2: in-vitro and ex-vivo fatigue damage of the cement mantle
Authors: Cristofolini L , Erani P , Savigni P , Bordini B , Viceconti M
Published: September 2007

Fatigue damage in the cement mantle surrounding hip stems has been studied in the past. However, so far no quantitative method has been validated for assessing ex-vivo damage and for predicting the in-vitro risk of cement fracture. This work presents a method for measuring cement damage; the cement mantle was sliced and sections were inspected with dye penetrants and an optical microscope. Cracks were counted, measured, and classified by type in each region of the cement mantle. Statistical indicators (in total and per unit volume of cement) were proposed that allow quantitative comparison. The method was first validated on two implant types with known clinical success rate, which were tested in vitro using a physiological loading profile (described in Part 1 of this work). The most relevant indicators were able to detect statistical differences between the two designs. Retrieved cement mantles (the same design as one of the in-vitro stems) from revision surgery were also processed with the same inspection method. Excellent qualitative and quantitative agreement was found between the in-vitro generated fatigue damage and the cracking pattern found in the ex-vivo retrieved cement mantles. This demonstrated the effectiveness of the cement inspection protocol and provided a further validation to the in-vitro testing method.
Lubrication regimes in lumbar total disc arthroplasty
Authors: Shaheen A , Shepherd D E T
Published: September 2007

A number of total disc arthroplasty devices have been developed. Some concern has been expressed that wear may be a potential failure mode for these devices, as has been seen with hip arthroplasty. The aim of this paper was to investigate the lubrication regimes that occur in lumbar total disc arthroplasty devices. The disc arthroplasty was modelled as a ball-and-socket joint. Elastohydrodynamic lubrication theory was used to calculate the minimum film thickness of the fluid between the bearing surfaces. The lubrication regime was then determined for different material combinations, size of implant, and trunk velocity. Disc arthroplasties with a metal-polymer or metal-metal material combination operate with a boundary lubrication regime. A ceramic-ceramic material combination has the potential to operate with fluid-film lubrication. Disc arthroplasties with a metal-polymer or metal-metal material combination are likely to generate wear debris. In future, it is worth considering a ceramic-ceramic material combination as this is likely to reduce wear.
Condition monitoring of an advanced gas-cooled nuclear reactor core
Authors: Pang Y , Giovanini L , Monari M , Grimble M
Published: September 2007

A critical component of an advanced gas-cooled reactor station is the graphite core. As a station ages, the graphite bricks that comprise the core can distort and may eventually crack. Since the core cannot be replaced, the core integrity ultimately determines the station life. Monitoring these distortions is usually restricted to the routine outages, which occur every few years, as this is the only time that the reactor core can be accessed by external sensing equipment. This paper presents a monitoring module based on model-based techniques using measurements obtained during the refuelling process. A fault detection and isolation filter based on unknown input observer techniques is developed. The role of this filter is to estimate the friction force produced by the interaction between the wall of the fuel channel and the fuel assembly supporting brushes. This allows an estimate to be made of the shape of the graphite bricks that comprise the core and, therefore, to monitor any distortion on them.
Non-parametric prediction of unobserved failure modes
Authors: Coolen F. P. A.
Published: September 2007

This paper presents the application of a recently developed non-parametric predictive inferential approach for multinomial data to the problem of prediction of occurrence of new failure modes. These inferences are in terms of lower and upper probabilities for the next observation. The lower probability of occurrence of a new failure mode is zero in all cases, as the data never suggest strongly that there have to be further failure modes. The main interest is in the upper probability that the next observed failure is caused by a new failure mode.
Wind Energy Potential of Southeast Anatolia Region of Turkey and an Optimum Wind Turbine Propeller Design for Siverek
Authors: Onat Cem , Canbazoğlu Suat
Published: September 2007

Continuing to use fossil fuels is bound to pollute the atmosphere, and consequently, unwanted greenhouse and climate change effects will come to dominate every part of the earth. It is, therefore, advisable to exploit clean energy resources for many nations in the world to try to keep their environment friendly, such as wind energy. Hence, it is necessary to determine to start the immediate usage of the wind energy potential and the investigation of the necessary techniques and economic feasibility in every country.

In this study, the wind energy potentials of Turkey and its Southeast Anatolia region were investigated and an optimum horizontal-axis wind turbine propeller was designed by using 144 different design parameters for NACA 4415 and LS-1 blade profiles and then the possible maximum electrical energy per year generated by the wind was also calculated by using meteorological data for Siverek.
Energetic Efficiency and Environmental, Economic, Societal Benefits of Microdiesel from Biowastes
Authors: Dai Chuanchao , Tao Jie , Zhao Mo , Jiang Baojuan
Published: September 2007

Lignocellulosic biowastes can be utilized to produce microdiesel, a promising alternative energy source for limited crude oil and food based biofuels. As an alternative fuel, microdiesel produced from lignocellulosic materials has superior environmental benefits; be economically competitive; be producible in sufficient quantities and the energy conversion efficiency was also estimated in the article in theory. In the article, Populus euramevicana cv leaves acid hydrolysate has been utilized as a substrate for microbial oil production using Rhodotorula glutinis. Microdiesel was further produced by transesterification and most properties complied with the limits established by ASTM related to biodiesel quality. In order to further reduce the cost, exogenous depolymerization enzymes used in the hydrolysis process could be replaced with plants that are capable of synthesizing these enzymes in situ and the cellulase and hemicellulase would be produced and break down the cell wall just before harvest.
Thermodynamic Evaluation of First and Second Law Performance of Evaporative Cooling Schemes for Regenerative Gas Turbines
Authors: Bolatturk Ali , Kanoglu Mehmet , Coskun Ahmet
Published: September 2007

In this study, effect of evaporative cooling on performance of regenerative gas turbine cycle is investigated considering simple regenerative cycle and regenerative cycle with intercooling and reheating. Evaporative cooling is applied to inlet air in simple regenerative cycle while it is applied to compressor inlet air and air between the compressor stages in reheat regenerative cycle. The first and second law performances of the cycles incorporating evaporative cooling are compared to the corresponding conventional cycles. Effects of the temperature and relative humidity of the ambient air, the turbine inlet temperature, and the pressure ratio on the net work, the thermal efficiency, and the second-law efficiency of the cycles are investigated. It appears that evaporative cooling increases thermal efficiency, net work, and optimum pressure ratio. With respect to simple regenerative cycle at a turbine inlet temperature of 1400 K and at a pressure ratio of 20, the thermal efficiency and the net work increase by 1.5 percent and 4 percent, respectively by inlet cooling in simple regenerative cycle while they increase by 18.3 percent and 12.2 percent, respectively by inlet cooling and intercooling in reheat regenerative cycle. With respect to conventional regenerative cycle with intercooling and reheating, evaporative cooling applied to inlet air and for intercooling provides essentially no increase in thermal and second-law efficiencies while it increases the net work 8.2 percent to 17.8 percent depending on the ambient conditions. Increasing turbine inlet temperature gives a linear increase in the optimum pressure ratio. As the ambient temperature increases and the relative humidity decreases, evaporative cooling becomes more effective in improving cycle performance.
Digital Implementation of Active Vibration Control of a Structure
Authors: Gupta A. , Yandamuri S. , Kuo S. M.
Published: September 2007

An adaptive feedback algorithm is designed and implemented on a digital signal processor (DSP) system for the active vibration control (AVC) of a small structure. Real time experimental results show that the convergence speed and stability of the system are related to the exciting frequency, filter order, and the sampling frequency. The theoretical upper bound of the sampling frequency for a particular exciting frequency and filter order is compared with experiment, which is very important for designing practical digital AVC applications that control low-frequency vibration using low-cost data converters such as coder-decoder chips that only support high sampling frequencies.
Air-Structure Coupling Characteristic Analysis of Fan Blade
Authors: Li Linling , Huang Qibai
Published: September 2007

For the fan structure, 8-node isoparametric quadrilateral elements are used to discretize the structure based on the fan blade shape while 20-node isoparametric hexahedron elements are used to discretize the surrounding air of the fan blade. The intensity of pressure at an arbitrary point in the surrounding air can be solved by the Galerkin method when the boundary condition is considered. The Wilson-Θ method with good stability is used to solve the air-structure coupling equations. The calculated natural modes and the tested natural modes are compared. The mode method is used to calculate and analyze the fan blade dynamic characteristics in order to study the air-structure coupling.
Extreme Wind Speed from Different Directions in Kuwait
Authors: Neelamani S. , Al-Awadhi Layla , Al-Ragum Alanoud , Al-Sudairawi Mane
Published: September 2007

Assessment of extreme wind speed for different return periods and from different directions is required for designing and choosing wind turbines. Extreme wind speed analysis for Kuwait is carried out based on the measured wind speed data at Kuwait International Airport from 1962 to 2002. The maximum expected 10 minute average wind speeds at 10 m elevation from the ground level and from 16 different directions and for different return periods were predicted using the Gumbel distribution. Consequently, the maximum wind speeds from NW and SE directions (which are the most predominant wind directions in Kuwait) for a return period of 100 years were 25 m/s and 22 m/s respectively; for SW and WSW directions, the maximum wind speeds for the 100 year return period were 33 m/s and 31 m/s respectively.