bluuebunny/crossref_metadata_2025 huggingface dataset:
PAS is optimal for diagnosing onychomycosis
Authors: Barak Orr , Asarch Adam , Horn Thomas
Published: April 2010

Onychomycosis is a frequently treated fungal infection of the nail plate with morbidity in high‐risk populations. The diagnosis often relies on histopathologic analysis of nail plate specimens with the assistance of special stains. Pathologists utilize periodic acid schiff (PAS) and/or Gomori methenamine silver (GMS) stains to highlight fungi within the nail plate. In a recent study of 51 PAS‐negative nail cases, it was concluded that GMS is superior to PAS in the diagnosis of onychomycosis. We expand on this study by investigating a larger number of PAS‐negative nail clippings determining whether GMS or PAS is superior in highlighting fungi in additional sections. There was no difference in the sensitivity of PAS vs. GMS (4.2 vs. 4.3%, p = 0.57); however, PAS was found to be significantly less expensive by 2.6‐fold. Taken together, these data suggest that the PAS stain is the optimal method for diagnosing onychomycosis.

Barak O, Asarch A, Horn T. PAS is optimal for diagnosing onychomycosis.
Use of simulated data from a process‐based habitat model to evaluate methods for predicting species occurrence
Authors: Hoffman Justin D. , Aguilar‐Amuchastegui Naikoa , Tyre Andrew J.
Published: April 2010

Much research has centered on determining which habitat model best predicts species occurrence. However, previous work typically used data sets that are inherently biased for evaluation. The use of simulated data provides a way of testing model performance using un‐biased data where the true relationships between species occurrence and population processes are predefined using sound ecological theory. We used a process‐based habitat model to generate simulated occurrence data to evaluate presence–absence and presence–only methods: generalized linear and generalized additive models (GLM, GAM), maximum entropy model (Maxent), and discrete choice models (DCM). This is the first study to use a DCM for predicting species distributions. We varied the effect that habitat quality had on fecundity and reported the model responses to these changes. When the effect of habitat quality on fecundity was weak, model performance was no better than random for all methods, however, performance increased as the habitat/fecundity relationship became stronger. For each level of habitat quality effect, there was little variation in performance between the presence–absence and presence–only methods. The use of a process‐based habitat model to generate occurrence data for evaluating model performance has a distinct advantage over other testing methods, because no errors are made during sampling and the true ecological relationships between population process and species occurrence are known. This leads to un‐biased results and increased confidence in assessing model performance and making management recommendations.
Predicting species distributions based on incomplete survey data: the trade‐off between precision and scale
Authors: Braunisch Veronika , Suchant Rudi
Published: April 2010

Systematic species surveys over large areas are mostly not affordable, constraining conservation planners to make best use of incomplete data. Spatially explicit species distribution models (SDM) may be useful to detect and compensate for incomplete information. SDMs can either be based on standardized, systematic sampling in a restricted subarea, or – as a cost‐effective alternative – on data haphazardly collated by “volunteer‐based monitoring schemes” (VMS), area‐wide but inherently biased and of heterogeneous spatial precision. Using data on capercaillie Tetrao urogallus, we evaluated the capacity of SDMs generated from incomplete survey data to localise unknown areas inhabited by the species and to predict relative local observation density. Addressing the trade‐off between data precision, sample size and spatial extent of the sampling area, we compared three different sampling strategies: VMS‐data collected throughout the whole study area (7000 km2) using either 1) exact locations or 2) locations aggregated to grid cells of the size of an average individual home range, and 3) systematic transect counts conducted within a small subarea (23.8 km2). For each strategy, we compared two sample sizes and two modelling methods (ENFA and Maxent), which were evaluated using cross‐validation and independent data. Models based on VMS‐data (strategies 1 and 2) performed equally well in predicting relative observation density and in localizing “unknown” occurrences. They always outperformed strategy 3‐models, irrespective of sample size and modelling method, partly because the VMS‐data provided the more comprehensive clues for setting the discrimination‐threshold for predicting presence or absence. Accounting for potential errors due to extrapolation (e.g. projections outside the environmental domain or potentially biasing variables) reduced, but did not fully compensate for the observed discrepancies. As they cover a broader range of species‐habitat relations, the area‐wide data achieved a better model quality with less a‐priori knowledge. Furthermore, in a highly mobile species like capercaillie a sampling resolution corresponding to an individuals' home range can lead to equally good predictions as the use of exact locations. Consequently, when a trade‐off between the sampling effort and the spatial extent of the sampling area is necessary, less precise data unsystematically collected over a large representative region are preferable to systematically sampled data from a restricted region.
Fire‐induced taxonomic and functional changes in saproxylic beetle communities in fire sensitive regions
Authors: Moretti Marco , De Cáceres Miquel , Pradella Cinzia , Obrist Martin K. , Wermelinger Beat , Legendre Pierre , Duelli Peter
Published: April 2010

It is often suggested that fire acts as an environmental filter that selects species and functional traits, and reduces trait variability within communities, affecting ecosystem function and underlying services. This may be particularly important in fire‐sensitive ecosystems, such as the central European Alps, where fires are scarce. According to climate and land use change scenarios in Europe, fire risk will increase during the next decades, raising important questions about the maintenance of ecological and functional resilience in these regions. We used two families of saproxylic beetles (i.e. Cerambycidae and Buprestidae) as model group to test the combined effect of fire and altitude on species and trait composition in the central Alps of Switzerland. Trait response was based on weighted means and variation of 15 traits over the communities. Our results showed an overall positive effect of fire on taxonomic and functional diversity, while indicator species and community analyses revealed that the response to fire was also modulated by altitude. The positive effect of fire and the presence of large populations of pyrophilous species suggest co‐evolution with fire and adaptation to disturbance in the Alps. Biodiversity in the central Alps might thus be more resilient to fire than expected. In the light of climatic and land use changes, forest management and species conservation in the central Alps have to consider fire one of the major disruptive factors that have shaped and will shape species composition and ecosystem services.
The molecular skin pathology of familial primary localized cutaneous amyloidosis
Authors: Tanaka Akio , Lai‐Cheong Joey E. , Van Den Akker Peter C. , Nagy Nikoletta , Millington George , Diercks Gilles F. H. , Van Voorst Vader Pieter C. , Clements Suzanne E. , Almaani Noor , Techanukul Tanasit , Hide Michihiro , South Andrew P. , McGrath John A.
Published: April 2010

Please cite this paper as: The molecular skin pathology of familial primary localized cutaneous amyloidosis. Experimental Dermatology 2010; 19: 416–423.

Abstract:  Familial primary localized cutaneous amyloidosis (FPLCA) is an autosomal dominant disorder associated with chronic itching and skin lichenification. In lesional skin, there are apoptotic basal keratinocytes and deposits of amyloid material on degenerate keratin filaments in the upper dermis. The genetic basis of FPLCA involves mutations in the OSMR and IL31RA genes but the disease pathophysiology is not fully understood. In this study, we identified new pathogenic heterozygous missense mutations in the OSMR gene (p.Val631Leu and p.Asp647Tyr) in two Dutch FPLCA families. We then compared gene expression profiles between FPLCA lesional skin (n = 4) and site‐matched control skin (n = 6). There was twofold or greater upregulation of 34 genes and downregulation of 43 genes. Most changes in gene expression (verified by quantitative RT‐PCR) reflected alterations in epidermal differentiation and proliferation consistent with lichenification, but we also noted a reduction in several interfollicular keratinocyte stem cell markers in FPLCA skin. Differences in gene expression were also noted for proteins involved in apoptosis and nerve conduction. Collectively, this study expands the molecular basis of FPLCA and provides new insight into the skin pathology of this condition.
Investigating Association of Three Polymorphisms of Coagulation Factor XIII and Recurrent Pregnancy Loss
Authors: Jeddi‐Tehrani Mahmood , Torabi Raheleh , Mohammadzadeh Afsaneh , Arefi Soheila , Keramatipour Mohammad , Zeraati Hojjat , Zarnani Amir Hasan , Akhondi Mohammad Mehdi , Mahmoudian Jafar , Mahmoudi Ahmad Reza , Zarei Saeed
Published: April 2010

Citation Jeddi‐Tehrani M, Torabi R, Mohammadzadeh A, Arefi S, Keramatipour M, Zeraati H, Zarnani AH, Akhondi MM, Mahmoudian J, Mahmoudi AR, Zarei S. Investigating association of three polymorphisms of coagulation factor XIII and recurrent pregnancy loss. Am J Reprod Immunol 2010; 64: 212–217

Problem  Among important suspected causes of thrombophilia in women with recurrent pregnancy loss (RPL) are the polymorphisms of coagulation factor XIII (FXIII) gene. We performed a case–control study on the association between three polymorphisms of factor XIII (FXIII G103T, FXIII A614T and FXIII C1694T) and RPL in Iranian women.

Method of study  DNA samples from peripheral blood of 100 female patients with at least two recurrent abortions, as case group, and 100 healthy women with history of at least two successful deliveries were subjected to PCR‐RFLP, and the frequencies of the polymorphisms were calculated and compared between the two groups.

Results  The prevalence of FXIII G103T polymorphism was 29% in the case group and 17% in the control group (P = 0.158). The frequencies of FXIII A614T and FXIII C1694T were 84% and 66% in the case group and 48% and 31% in the control group (P < 0.001 and P < 0.001), respectively. The two latter polymorphisms are associated with RPL in Iranian women and increase the risk of RPL. A correlation was also found between FXIII A614T and FXIII C1694T polymorphisms (P < 0.001).

Conclusion  We suggest the evaluation of FXIII A614T and FXIII C1694T polymorphisms in women with RPL.
Pregnancy Complication and Outcome in Women with History of Allergy to Medicinal Agents
Authors: Ohel Iris , Levy Amalia , Zweig Aya , Holcberg Gershon , Sheiner Eyal
Published: April 2010

Citation Ohel I, Levy A, Zweig A, Holcberg G, Sheiner E. Pregnancy complication and outcome in women with history of allergy to medicinal agents. Am J Reprod Immunol 2010; 64: 152–158

Problem  Pregnancy outcome in women with a previous history of drug allergy and the role of drug allergies in adverse pregnancy outcomes is unclear.

Method of study  A retrospective cohort study comparing pregnancies of women with and without history of drug allergy was conducted. Data were collected from the computerized perinatal database. A multiple logistic regression model, with background elimination, was constructed to control for confounders.

Results  Of 186,443 deliveries, 4.6% (n = 8647) occurred in patients with a history of drug allergy. The following conditions were significantly associated with a history of drug allergy: advanced maternal age, recurrent abortions, fertility treatments, hypertensive disorders, and diabetes mellitus. Using multivariate analysis, with background elimination, history of drug allergy was significantly associated with intrauterine growth restriction (OR = 1.52, CI = 1.3–0.8, P < 0.001) and with preterm delivery (OR = 1.26, CI = 1.14–1.38, P < 0.001).

Conclusion  A history of drug allergy is an independent risk factor for intrauterine growth restriction and preterm delivery. Further prospective studies are needed to investigate the nature of this association.
All in the mind? Why social inequalities persist
Authors: Dorling Danny
Published: April 2010

Danny Dorling suggests that as old ‘social evils’ have largely been overcome in affluent nations, in one of the most unequal of those countries – Britain – they have transformed into five new tenets of injustice. A continued belief in those tenets both maintains and helps to exacerbate social inequality
The bishops' 1909 moment
Authors: McLean Iain
Published: April 2010

Twenty‐six Church of England bishops sit by right in the United Kingdom's Parliament, making laws. Why? And is there any coherent reason why this should continue, asks Iain McLean
PHYSICOCHEMICAL, NUTRITIONAL AND MICROBIAL QUALITY OF FRESH‐CUT AND FROZEN PAPAYA PREPARED FROM CULTIVARS WITH VARYING RESISTANCE TO INTERNAL YELLOWING DISEASE
Authors: WALL M.M. , NISHIJIMA K.A. , FITCH M.M. , NISHIJIMA W.T.
Published: April 2010

Quality, nutritional and microbial analyses were completed for fresh‐cut and frozen papaya cubes prepared from cultivars with varying resistance to internal yellowing (IY) disease caused by the bacterium Enterobacter cloacae. In general, fresh‐cut and frozen papaya retained nutritional and microbial quality, but visual and textural quality declined. Fresh‐cut fruit pretreated with 1% calcium lactate solution were firmer than control fruit, but translucency limited the shelf life of cubes dipped in either water or calcium lactate. Vitamin C content averaged 61.5 mg/100 g and 52.2 mg/100 g for fresh‐cut and frozen fruit, respectively. Vitamin A content was greatest in fresh‐cut “Laie Gold” and “Rainbow” fruit, and averaged 35.1 µg retinol activity equivalents per 100 g for all cultivars. Microbial counts were very low or not detectable for most samples. Among the cultivars resistant to IY, “Rainbow” had the highest vitamin A and sugar contents, and did not develop translucency.

PRACTICAL APPLICATIONS

This study provides new nutritional information for fresh‐cut and frozen papaya products that can be included in the U.S. Department of Agriculture National Nutrient Database. Also, data on cultivar attributes may assist processors of fresh‐cut or frozen papaya products in choosing the best cultivars by considering appearance, texture, flavor, nutritional content and microbial quality. The selection of papaya cultivars with resistance to internal yellowing disease will allow processors to produce nutritious value‐added products that conform to food safety guidelines.
INVESTIGATION OF CHEMICAL QUALITY OF SUGARCANE (SACCHARUM OFFICINARUM L.) WINE DURING FERMENTATION BY SACCHAROMYCES CEREVISIAE
Authors: TZENG DAW‐I. , CHIA YI‐CHEN , TAI CHAO‐YING , OU ANDI SHAU‐MEI
Published: April 2010

The purpose of this study was to examine the changes in the contents of sugar, ethanol, organic acids, volatile compounds, pH and acidity in sugarcane wine during fermentation using Saccharomyces cerevisiae and the consumer preference test was also conducted to investigate the optimal fermentation. According to the results, the maximal population of S. cerevisiae reached to 8.12 log cfu/mL at the sixth day of fermentation. The maximum ethanol content, 15.16%, was obtained at the ninth day, while the sucrose and glucose concentrations were almost exhausted at the same time. As for organic acids, citric acid was detected as the most abundant one at the second day of fermentation, followed by lactic and succinic acids. The volatile compounds were analyzed by SPME/GC‐MS, and the concentrations of alcohols, esters and acids were all highest in sugarcane wine at the sixth day of fermentation. The results have demonstrated that sugarcane wine fermentation with S. cerevisiae at the sixth day is enough to reach the highest aroma quality as indicated by the highest esters/alcohols in the wine and the most abundant amount of aroma‐related compounds. The overall preference of consumer test also supports the above result with the sugarcane wine fermented at day 6 having highest scores.

PRACTICAL APPLICATIONS

Sugarcane with high content of sugar is a potential material for making vinegar through alcoholic and acetous fermentation. Because the sugarcane wine as well as sugarcane vinegar is seldom available in Taiwan or other places, it is beneficial to study how to effectively use the sugarcane other than just consumed as a kind of fresh fruit or a juice drink. The economic value of wine is highly depended on its composition changes and consumer's preference. Although there are a few reports working on the chemical compounds during fermentation of sugarcane wine, there is little concerning the consumer‐type preference parallel to the chemical analysis during fermentation. Following the identification of winemaking fermenting yeast strain, Saccharomyces cerevisiae, isolated from liquor rice dregs and the establishment of the fermenting condition for making sugarcane wine carried out in our previous studies, in this study, we analyzed the composition of volatile compounds in sugarcane wine and characterized the associated changes in chemical properties during fermentation. In addition, the consumer preference test was also carried out to verify the results of chemical property analysis. It is hoped the strategy of this study to be a reference prior to industry scale for manufacturing process and quality improvement of sugarcane wine and other wines.
STUDIES ON COFFEE ROASTING PROCESS BY MEANS OF NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
Authors: CIAMPA A. , RENZI G. , TAGLIENTI A. , SEQUI P. , VALENTINI M.
Published: April 2010

The chemical composition of coffee has been widely investigated, focusing the attention both on main components and trace compounds. Most of these studies have been performed by using liquid and gas chromatography, eventually combined with mass spectroscometry. These techniques, although straight and effective, are time demanding due to the sample pretreatments. Here, we propose high‐resolution‐magic‐angle spinning nuclear magnetic resonance spectroscopy (HR‐MAS NMR), a system capable of acquiring highly resolved NMR spectra of gel‐like and suspension samples. This approach allowed us to determine the chemical composition of coarsely ground coffee beans of two varieties: Arabica and Robusta. Variation of the concentration of relevant species was monitored as a function of roasting temperature, from green beans to completely roasted. The HR‐MAS NMR tool demonstrated to be very powerful for quick chemical composition determination, opening up possibilities for novel applications of this approach in food quality control.

PRACTICAL APPLICATIONS

Food quality control needs novel and press‐button applications. High‐resolution‐magic‐angle spinning nuclear magnetic resonance contains such requirements, since it can analyze suspension and gel‐like samples, providing a chemical characterization with minor, or, in most cases, no chemical and physical pretreatment operations. The application proposed here concerns the examination of relevant molecules in coffee beans as a function of the roasting temperature. This can be used for a quality check of the final product, and such approach has a general suitability, being functional for almost all foodstuff, fresh and transformed.
CHEMOMETRIC STUDIES FOR QUALITY CONTROL OF PROCESSED BRAZILIAN COFFEES USING DRIFTS
Authors: RIBEIRO JULIANO S. , SALVA TEREZINHA J. , FERREIRA MÁRCIA M.C.
Published: April 2010

In this work, the potential of mid‐infrared diffuse reflectance spectroscopy with Fourier transform for discrimination of 29 commercial Brazilian coffee samples with different industrial processing, i.e., caffeine extraction and roasting degree, was evaluated. The statistical treatments applied to pre‐treated spectral data were principal component analysis and partial least squares – discriminant analysis (PLS‐DA). The ordered predictors selection method was used for variable selection. The chemometric analyses of the mid‐infra‐red spectra allowed inferring on the lower carbohydrate, caffeine and chlorogenic acid concentration as well as on the higher water content in the decaffeinated coffee. The technique also allowed speculation on the higher lipid and lower water content in the dark roasted coffee compared with traditional roasted coffee. A clear discrimination of decaffeinated from medium and dark roasted coffees was observed in PC1. PLS‐DA was used for the discrimination between medium and dark roasted coffees. A model with one latent variable correctly classified 100% of the external validation and prediction samples according to their roasting degree.

PRACTICAL APPLICATIONS

Diffuse reflectance mid infrared spectroscopy (DRIFTS), principal component analysis and partial least squares were successfully applied to discriminate decaffeinated coffees from nondecaffeinated coffees and to discriminate roasted coffees by their roasting degree. This study have shown that DRIFTS coupled with chemometrics consists in a simple and straightforward analytical method for monitoring the roasted coffee authenticity, and the results could help in developing an alternative and inexpensive method for quality control of coffee products.
Treatment and prognostic factors of papillary thyroid microcarcinoma
Authors: Giordano D. , Gradoni P. , Oretti G. , Molina E. , Ferri T.
Published: April 2010

Clin. Otolaryngol. 2010, 35, 118–124

Objective:  To discuss the prognostic factors and outcomes of treatment in patients diagnosed with papillary thyroid microcarcinoma.

Design:  Retrospective observational case review.

Setting:  Department of Otorhinolaryngology of the tertiary referral teaching hospital of Parma.

Participants:  Ninety‐seven patients diagnosed with PTMC and surgically treated between January 1998 and December 2007.

Main outcome measures:  Clinical and histopathological characteristics of the study group were identified and statistically analysed.

Results:  No cancer‐related deaths were registered. Incidence of recurrent disease was 9% after a 43 month mean follow‐up (range 12–120). Univariate analysis detected that metastases in neck lymph nodes at diagnosis (p = 0.025), a tumour >5 mm in size (p = 0.011), the presence of bilateral tumoural foci (p = 0.007), the presence of capsular invasion (p = 0.001), and the presence of vascular invasion (p = 0.004) were related to recurrent disease. On multivariate analysis, the presence of bilateral tumoural foci (p = 0.030), and the presence of capsular invasion (p = 0.005) were significantly related to tumour recurrence.

Conclusion:  The prognosis for patients with papillary thyroid microcarcinoma in this series was excellent, with a 100% survival rate and minimal surgical‐related morbidity. Nevertheless, approximately 10% of patients developed recurrent disease; aggressive treatment may be justified depending on the presence or absence of prognostic risk factors.
Exploring the variation in paediatric tonsillectomy rates between English regions: a 5‐year NHS and independent sector data analysis
Authors: Suleman M. , Clark M.P.A. , Goldacre M. , Burton M.
Published: April 2010

Clin. Otolaryngol. 2010, 35, 111–117

Objectives:  Tonsillectomy rates vary between locations and socio‐economic groups and have been noted to do so since the 1930s. We aimed, first, to illustrate the current extent of variation in rates in the NHS across England and, second, to explore whether any observed geographical variation could be accounted for by combining independent sector data with standard NHS datasets.

Methods:  Analysis of NHS Hospital Episode Statistics data for tonsillectomy in people aged under 15 years, from April 1 2000 to March 31 2005; addition of data from a major independent sector provider of surgery; ranking of local authority areas according to tonsillectomy rates including and excluding independent sector data.

Results:  The national annual average tonsillectomy rate for the NHS was 304 per 100 000 population aged <15 (95% CI 320–324). The highest rate was 754 (95% CI 690–822) and the lowest 102 (95% CI 83–125). This seven‐fold difference cannot simply be explained by a small number of high or low ‘outliers’. When rates in the NHS were ranked and compared with the ranking of rates in the independent sector data, a Kendall tau rank correlation coefficient of 0.003 showed that there was no inverse correlation between the two rankings. That is, low NHS rates were not associated with high independent sector rates or vice versa.

Conclusions:  There is currently a seven‐fold variation in tonsillectomy rates across local authority areas in England. The variation in tonsillectomy rates found in NHS data on surgical workload does not appear to be explained by the exclusion of data from the independent sector.
Randomised cross‐over study of oral appliances for snoring
Authors: Maguire J. , Steele J.G. , Gibson G.J. , Wilson J.A. , Steen N. , McCracken G.I.
Published: April 2010

Clin. Otolaryngol. 2010, 35, 204–209

Objectives:  To compare a mandibular advancement splint to a control bite raising appliance in the treatment of snoring with or without mild obstructive sleep apnoea syndrome.

Design:  A prospective two‐treatment randomised cross‐over clinical trial.

Setting:  Single centre secondary care Dental Hospital.

Participants:  Fifty‐two subjects (36 men, 16 women) diagnosed with non‐apnoeic snoring or mild obstructive sleep apnoea syndrome (apnoea/hypopnoea index ≤15 events/h), were recruited from Departments of Respiratory Medicine and ENT surgery, Newcastle upon Tyne Hospitals NHS Foundation Trust.

Main outcome measures:  The Snoring Symptoms Inventory questionnaire (SSI) and the Epworth Sleepiness Score (ESS) were used to evaluate changes in symptoms. Patient reported outcomes (compliance, adverse events, splint preference) were recorded by questionnaire. Subjects attended for five study visits and used a mandibular advancement splint and a bite raising appliance at home each for 4 weeks, with a 3‐week washout period between devices.

Results and conclusions:  Thirty‐eight subjects completed the study. Both the mandibular advancement splint and bite raising appliance significantly reduced the SSI compared to the baseline scores: mandibular advancement splint 5.5, P = 0.013; bite raising appliance 3.1, P = 0.005. No statistically significant difference between the two treatment periods was detected (P > 0.05). The reduction in the Epworth Sleepiness Score was: mandibular advancement splint 1.0, P = 0.02; bite raising appliance 0.3, P = 0.4. The change in the Epworth Sleepiness Score was not statistically significantly different between the mandibular advancement splint and bite raising appliance treatment periods (P > 0.05).

Conclusions:  In this cohort of patients diagnosed with snoring ± mild OSA:

both the mandibular advancement splint and bite raising appliance designs of splint appeared to reduce the symptoms of snoring;

no difference in the magnitude of this effect was detected in favour of one design of splint.
The Epidemiology of Dementia Associated with Parkinson's Disease
Authors: Aarsland Dag , Kurz Martin Wilhelm
Published: April 2010

Parkinson's disease (PD) is the second most common neurodegenerative illness after Alzheimer's disease (AD). Cognitive impairment and dementia are common features in PD and characterized by a wide range of cognitive deficits distinct from those seen in AD. Mild cognitive impairment occurs even early in PD and is associated with shorter time to dementia. The purpose of this review is to present recent findings on clinical aspects of dementia in PD and to elucidate underlying clinical and neurobiological risk factors.
Profile of Cognitive Impairment in Parkinson's Disease
Authors: Watson G. Stennis , Leverenz James B.
Published: April 2010

Cognitive impairment (CI) is a common nonmotor complication of Parkinson's disease (PD), and is associated with significant disability for patients and burden for caregivers. Similar to motor symptoms, the characteristics of CI in PD can be quite variable, both in terms of what cognitive domains are impaired, and the timing of onset and rate of progression. This review will examine the profile of cognitive domain impairments observed in PD, with a focus on early CI (without dementia). We will also discuss possible relationships between specific cognitive domain impairments in PD and pathological processes such as Lewy‐related pathology and Alzheimer's disease. It is our hypothesis that the specific characteristics of CI observed in individual PD patients provide clues to the underlying pathological processes, and that understanding the biological basis of this clinical phenomenon will assist in directing disease‐specific treatments. Given the high lifetime risk for CI in PD, it is imperative that we improve our understanding and treatments for this common and disabling problem in PD.
1998 Turbomachinery Committee Best Paper Award: An Experimental Study of Tip Clearance Flow in a Radial Inflow Turbine
Authors: Dambach R. , Hodson H. P. , Huntsman I.
Published: April 2010

This paper describes an experimental investigation of tip clearance flow in a radial inflow turbine. Flow visualization and static pressure measurements were performed. These were combined with hot-wire traverses into the tip gap. The experimental data indicate that the tip clearance flow in a radial turbine can be divided into three regions. The first region is located at the rotor inlet, where the influence of relative casing motion dominates the flow over the tip. The second region is located toward midchord, where the effect of relative casing motion is weakened. Finally, a third region exists in the exducer, where the effect of relative casing motion becomes small and the leakage flow resembles the tip flow behavior in an axial turbine. Integration of the velocity profiles showed that there is little tip leakage in the first part of the rotor because of the effect of scraping. It was found that the bulk of tip leakage flow in a radial turbine passes through the exducer. The mass flow rate, measured at four chordwise positions, was compared with a standard axial turbine tip leakage model. The result revealed the need for a model suited to radial turbines. The hot-wire measurements also indicated a higher tip gap loss in the exducer of the radial turbine. This explains why the stage efficiency of a radial inflow turbine is more affected by increasing the radial clearance than by increasing the axial clearance.
1998 Heat Transfer Committee Best Paper Award: Complementary Velocity and Heat Transfer Measurements in a Rotating Cooling Passage With Smooth Walls
Authors: Bons J. P. , Kerrebrock J. L.
Published: April 2010

An experimental investigation was conducted on the internal flowfield of a simulated smooth-wall turbine blade cooling passage. The square cross-sectioned passage was manufactured from quartz for optical accessibility. Velocity measurements were taken using Particle Image Velocimetry for both heated and non-heated cases. Thin film resistive heaters on all four exterior walls of the passage allowed heat to be added to the coolant flow without obstructing laser access. Under the same conditions, an infrared detector with associated optics collected wall temperature data for use in calculating local Nusselt number. The test section was operated with radial outward flow and at values of Reynolds number and Rotation number typical of a small turbine blade. The density ratio was 0.27. Velocity data for the non-heated case document the evolution of the Coriolis-induced double vortex. The vortex has the effect of disproportionately increasing the leading side boundary layer thickness. Also, the streamwise component of the Coriolis acceleration creates a considerably thinned side wall boundary layer. Additionally, these data reveal a highly unsteady, turbulent flowfield in the cooling passage. Velocity data for the heated case show a strongly distorted streamwise profile indicative of a buoyancy effect on the leading side. The Coriolis vortex is the mechanism for the accumulation of stagnant flow on the leading side of the passage. Heat transfer data show a maximum factor of two difference in the Nusselt number from trailing side to leading side. A first-order estimate of this heat transfer disparity based on the measured boundary layer edge velocity yields approximately the same factor of two. A momentum integral model was developed for data interpretation, which accounts for coriolis and buoyancy effects. Calculated streamwise profiles and secondary flows match the experimental data well. The model, the velocity data, and the heat transfer data combine to strongly suggest the presence of separated flow on the leading wall starting at about five hydraulic diameters from the channel inlet for the conditions studied.
Influence of Vane-Blade Spacing on Transonic Turbine Stage Aerodynamics: Part I—Time-Averaged Data and Analysis
Authors: Venable B. L. , Delaney R. A. , Busby J. A. , Davis R. L. , Dorney D. J. , Dunn M. G. , Haldeman C. W. , Abhari R. S.
Published: April 2010

A comprehensive study has been performed to determine the influence of vane-blade spacing on transonic turbine stage aerodynamics. In Part I of this paper, an investigation of the effect of turbine vane–blade interaction on the time-mean airfoil surface pressures and overall stage performance parameters is presented. Experimental data for an instrumented turbine stage are compared to two- and three-dimensional results from four different time-accurate Navier–Stokes solvers. Unsteady pressure data were taken for three vane-blade row spacings in a short-duration shock tunnel using surface-mounted, high-response pressure sensors located along the midspan of the airfoils. Results indicate that while the magnitude of the surface pressure unsteadiness on the vane and blade changes significantly with spacing, the time-mean pressures and performance numbers are not greatly affected.
Influence of Vane-Blade Spacing on Transonic Turbine Stage Aerodynamics: Part II—Time-Resolved Data and Analysis
Authors: Busby J. A. , Davis R. L. , Dorney D. J. , Dunn M. G. , Haldeman C. W. , Abhari R. S. , Venable B. L. , Delaney R. A.
Published: April 2010

This paper presents results of a combined experimental/computational investigation into the effects of vane–blade spacing on the unsteady aerodynamics of a transonic turbine stage. Time-resolved data were taken in a shock-tunnel facility in which the flow was generated with a short-duration source of heated and pressurized air. This data is compared with the results obtained from four unsteady Navier–Stokes solvers. The time-resolved flow for three axial spacings is examined. For each vane–blade spacing, the inlet conditions were nearly identical and the vane exit flow was transonic. Surface-mounted high-response pressure transducers at midspan were used to obtain the pressure measurements. The computed two-dimensional unsteady airfoil surface pressure predictions are compared with the Kulite pressure transducer measurements. The unsteady and axial spacing effects on loading and performance are examined. In general the numerical solutions compared very favorably with each other and with the experimental data. The overall predicted stage losses and efficiencies did not vary much with vane/blade axial spacing. The computations indicated that any increases in the blade relative total pressure loss were offset by a decrease in vane loss as the axial spacing was decreased. The decrease in predicted vane total pressure loss with decreased axial spacing was primarily due to a reduction in the wake mixing losses. The increase in predicted blade relative total pressure loss with a decrease in axial spacing was found to be mainly due to increased vane wake/blade interaction.
Experimental Investigation of Unsteady Flow Phenomena in a Centrifugal Compressor Vaned Diffuser of Variable Geometry
Authors: Justen F. , Ziegler K. U. , Gallus H. E.
Published: April 2010

The behavior of vaned radial diffusers is generally considered to be due to the flow phenomena in the vaneless and the semi-vaned space in the diffuser inlet region. Even considering unsteady aspects, the adjacent diffuser channel is regarded as less important. The flat wedge vaned diffuser of the centrifugal compressor stage investigated allows an independent continuous adjustment of the diffuser vane angle and the radial gap between impeller outlet and diffuser vane inlet, so that information about the importance of these geometric parameters can be obtained. The time-dependent pressure distribution on the diffuser front wall and on the suction and pressure surfaces of the diffuser vanes reveal that in the semi-vaned space mainly the region near the vane suction side is influenced by the unsteady impeller-diffuser interaction. Downstream in the diffuser channel the unsteadiness does not decay. Here, pressure fluctuations are appearing that are distinctly higher than the pressure fluctuations in the vaneless space. An estimation of the influence of the unsteadiness on the operating performance of the centrifugal compressor stage is made by measurements at choke and surge limit for different diffuser geometries.
Local Measurement of Loss Using Heated Thin-Film Sensors
Authors: Davies M. R. D. , O’Donnell F. K.
Published: April 2010

A calibration equation is derived linking the nondimensional entropy generation rate per unit area with the nondimensional aerodynamic wall shear stress and free-stream pressure gradient. It is proposed that the latter quantities, which can be measured from surface sensors, be used to measure the profile entropy generation rate. It is shown that the equation is accurate for a wide range of well-defined laminar profiles. To measure the dimensional entropy generation rate per unit area requires measurement of the thickness of the boundary layer. A general profile equation is given and used to show the range of accuracy of a further simplification to the calibration. For flows with low free-stream pressure gradients, the entropy generation rate is very simply related to the wall shear stress, if both are expressed without units. An array of heated thin film sensors is calibrated for the measurement of wall shear stress, thus demonstrating the feasibility of using them to measure profile entropy generation rate.
Heat Transfer Committee Best Paper of 1995 Award: Distribution of Film-Cooling Effectiveness on a Turbine Endwall Measured Using the Ammonia and Diazo Technique
Authors: Friedrichs S. , Hodson H. P. , Dawes W. N.
Published: April 2010

The distribution of adiabatic film-cooling effectiveness on the endwall of a large-scale low-speed linear turbine cascade has been measured using a new technique. This technique is based on an established surface-flow visualization technique, and makes use of the reaction between ammonia gas and a diazo surface coating. A new method of calibration has been developed to relate the result of the reaction to surface concentration of coolant. Using the analogy that exists between heat and mass transfer, the distribution of film-cooling effectiveness can then be determined. The complete representation of the film-cooling effectiveness distribution provided by the technique reveals the interaction between the coolant ejected from the endwall and the secondary flow in the turbine blade passage. Over- and undercooled regions on the endwall are identified, illustrating the need to take these interactions into account in the design process. Modifications to the cooling configuration examined in this paper are proposed as a result of the application of the ammonia and diazo technique.
Performance Improvement Through Indexing of Turbine Airfoils: Part 2—Numerical Simulation
Authors: Griffin L. W. , Huber F. W. , Sharma O. P.
Published: April 2010

An experimental/analytical study has been conducted to determine the performance improvements achievable by circumferentially indexing succeeding rows of turbine stator airfoils. A series of tests was conducted to experimentally investigate stator wake clocking effects on the performance of the space shuttle main engine (SSME) alternate turbopump development (ATD) fuel turbine test article (TTA). The results from this study indicate that significant increases in stage efficiency can be attained through application of this airfoil clocking concept. Details of the experiment and its results are documented in part 1 of this paper. In order to gain insight into the mechanisms of the performance improvement, extensive computational fluid dynamics (CFD) simulations were executed. The subject of the present paper is the initial results from the CFD investigation of the configurations and conditions detailed in part 1 of the paper. To characterize the aerodynamic environments in the experimental test series, two-dimensional, time-accurate, multistage, viscous analyses were performed at the TTA midspan. Computational analyses for five different circumferential positions of the first stage stator have been completed. Details of the computational procedure and the results are presented. The analytical results verify the experimentally demonstrated performance improvement and are compared with data whenever possible. Predictions of time-averaged turbine efficiencies as well as gas conditions throughout the flow field are presented. An initial understanding of the turbine performance improvement mechanism based on the results from this investigation is described.
The Transport of Vortices Through a Turbine Cascade
Authors: van de Wall A. G. , Kadambi J. R. , Boyle R. J. , Adamczyk J. J.
Published: April 2010

An experiment was conducted to determine how incident vortices created by upstream blade rows interacted with a downstream turbine cascade. Specifically, the kinematics of the vortex transport through turbine blade passages was investigated. A stationary water table and a flow visualization system using the pH indicator Bromothymol Blue was used to visualize the vortices generated by vortex generators placed upstream of a turbine blade cascade. Two test series were conducted. In the first test series, stationary vortex generators were positioned at various locations along the turbine blade pitch to observe how a steady incident streamwise vortex was transported through the turbine cascade. Observations showed an unsteady vortex response of the streamwise vortex when the incident vortex was located at the stagnation area of the blade. In the second test series, the vortex generators were moved to simulate the relative motion of an upstream blade row. In these tests, the unsteady vortex response was no longer seen at the stagnation region but was instead located at the suction side of the blade. In addition, the breakdown of the vortex varied greatly with the reduced frequency of the incident vorticity and showed an “explosive” type vortex breakdown that occurred at reduced frequencies greater than 8. The dissimilar behavior between the stationary and moving incident vortices indicates that losses and leading edge heat transfer could differ to some degree when determined from a stationary test as opposed to a full-stage simulation.
Rotor-Stator Interaction Analysis Using the Navier–Stokes Equations and a Multigrid Method
Authors: Arnone A. , Pacciani R.
Published: April 2010

A recently developed, time-accurate multigrid viscous solver has been extended to the analysis of unsteady rotor–stator interaction. In the proposed method, a fully implicit time discretization is used to remove stability limitations. By means of a dual time-stepping approach, a four-stage Runge–Kutta scheme is used in conjunction with several accelerating techniques typical of steady-state solvers, instead of traditional time-expensive factorizations. The accelerating strategies include local time stepping, residual smoothing, and multigrid. Two-dimensional viscous calculations of unsteady rotor–stator interaction in the first stage of a modern gas turbine are presented. The stage analysis is based on the introduction of several blade passages to approximate the stator:rotor count ratio. Particular attention is dedicated to grid dependency in space and time as well as to the influence of the number of blades included in the calculations.
Stall Inception Measurements in a High-Speed Multistage Compressor
Authors: Escuret J. F. , Garnier V.
Published: April 2010

This paper presents unsteady measurements taken in a high-speed four-stage aeroengine compressor prior to the onset of aerodynamic flow instabilities. In this experiment, 40 fast-response pressure transducers have been located at various axial and circumferential positions throughout the machine in order to give a very detailed picture of stall inception. At all the compressor speeds investigated, the stall pattern observed is initiated by a very short length-scale finite-amplitude disturbance, which propagates at a fast rate around the annulus. This initial stall cell leads to a large-amplitude system instability in less than five rotor revolutions. Varying the IGV setting angle is found to have a strong influence on the axial location of the first disturbance detected. In particular, transferring the aerodynamic loading from front to downstream stages moves the first disturbance detected from the first to the last stage of the compressor. Other repeatable features of the stall inception pattern in this compressor have been identified using a simple analysis technique particularly appropriate to the study of short length-scale disturbances. It is found that the origins of instabilities are tied to particular tangential positions in both the stationary and rotating frames of reference. These measurements lead to the conclusion that the stall inception process in high-speed multistage compressors can be characterized by some very local and organized flow phenomena. Moreover, there is no evidence of prestall waves in this compressor.
Transition Length Prediction for Flows With Rapidly Changing Pressure Gradients
Authors: Solomon W. J. , Walker G. J. , Gostelow J. P.
Published: April 2010

A new method for calculating intermittency in transitional boundary layers with changing pressure gradients is proposed and tested against standard turbomachinery flow cases. It is based on recent experimental studies, which show the local pressure gradient parameter to have a significant effect on turbulent spot spreading angles and propagation velocities (and hence transition length). This can be very important for some turbomachinery flows. On a turbine blade suction surface, for example, it is possible for transition to start in a region of favorable pressure gradient and finish in a region of adverse pressure gradient. Calculation methods that estimate the transition length from the local pressure gradient parameter at the start of transition will seriously overestimate the transition length under these conditions. Conventional methods based on correlations of zero pressure gradient transition data are similarly inaccurate. The new calculation method continuously adjusts the spot growth parameters in response to changes in the local pressure gradient through transition using correlations based on data given in the companion paper by Gostelow et al. (1996). Recent Experimental Correlations of Gostelow et al. (1994a) are used to estimate the turbulent spot generation rate at the start of transition. The method has been incorporated in a linear combination integral computation and tested with good results on cases that report both the intermittency and surface pressure distribution data. It has resulted in a much reduced sensitivity to errors in predicting the start of the transition zone, and can be recommended for engineering use in calculating boundary layer development on axial turbomachine blades.