bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the β-quartz hexagonal cell parameters from a 00.1 neutron multiple diffractionUmweganregungpattern measured at 1003 K
Authors: de Campos Luiz Carlos , Parente Carlos Benedicto Ramos , Mazzocchi Vera Lucia
Published: October 2010

The hexagonal cell parametersaandcof β-quartz have been determined from a 00.1 β-quartz neutron multiple diffractionUmweganregungpattern measured at 1003 K. Owing to the high density of multiple diffraction peaks in the indexing of the pattern, contrasting with the low density of experimental peaks, a procedure to correctly index peaks has first been applied. After the correct indexing, the peaks were selected taking into account their quality (adequate intensity and definition) and then classified in accordance with their suitability for the determination ofaorc. The azimuthal angular positions of classified peaks were applied to indexing diagrams in order to obtain sets of values for bothaandc. Weighted means of the sets give final values foraandc. In order to obtain more reliable final values an iterative process has been employed. A statistical analysis of data has also been employed to calculate uncertainties for the mean values found in the iterative process. After 12 cycles of iteration, the results converged toa= 4.9957 (14) andc= 5.46184 (35) Å for β-quartz at 1003 K.
Jpowder: a Java-based program for the display and examination of powder diffraction data
Authors: Markvardsen Anders J. , Puphaiboon Kreecha , Arjeneh Mohammad , Shankland Kenneth , Guest Hannah L. , Griffin Thomas A. N. , Badham Daniel R. , Flannery Damian W.
Published: October 2010

The ability to display and inspect powder diffraction data quickly and efficiently is a central part of the data analysis process. Whilst many computer programs are capable of displaying powder data, their focus is typically on advanced operations such as structure solution or Rietveld refinement. This article describes a lightweight software package,Jpowder, whose focus is fast and convenient visualization and comparison of powder data sets in a variety of formats from computers with network access.Jpowderis written in Java and uses its associated Web Start technology to allow `single-click deployment' from a web page, http://www.jpowder.org.Jpowderis open source, free and available for use by anyone.
The effect of compaction on soil electrical resistivity: a laboratory investigation
Authors: Seladji S. , Cosenza P. , Tabbagh A. , Ranger J. , Richard G.
Published: October 2010

Among the geophysical tools used in soil science, electrical methods are considered as potentially useful to characterize soil compaction intensity. A laboratory investigation was undertaken on agricultural and forest soils in order to study the impact of compaction on bulk soil electrical resistivity. Samples taken from four different types of loamy soils were compacted at three bulk densities (1.1, 1.3 and 1.6 g cm−3). Bulk soil resistivity was measured at each compacted state for gravimetric water contents ranging from 0.10 to 0.50 g g−1. A specific experimental procedure allowed the control of the water‐filling of the intra‐aggregate pores and the inter‐aggregate pores. Soil resistivity decreased significantly with increase in density and typically for gravimetric water contents less than 0.25 g g−1. The decrease was more pronounced for the drier soils, indicating the strong impact of the surface conductance, especially in agricultural soils. The experimental data were in good agreement with simulated values given by the petro‐physical model of Waxman‐Smits (1968), at least for water saturation greater than 0.3. The analysis of the petro‐physical parameters derived from the experimental data suggested that: (i) the electrical tortuosity of the loamy agricultural soil was significantly affected by compaction and (ii) the forest soil had a singular microstructure from an electrical point of view and had isolated conductive zones associated with clay embedded in a poorly conductive medium comprised mainly of soil solution and quartz grains. Our results provide the phenomenological basis for assessing, in the field, the relationship between soil electrical resistivity and compaction intensity.
Qualitative research in nutrition and dietetics: getting started
Authors: Swift J. A. , Tischler V.
Published: October 2010

Qualitative research is well placed to answer complex questions about food‐related behaviour because it investigates how and why individuals act in certain ways. The field of qualitative health research is undoubtedly gaining momentum and, increasingly, there is a recognition that it should be a vital part of the decision‐making processes that direct the development of health policy and practice. Much of the guidance available, however, is difficult to navigate for those new to ‘qualitative research’, and there is little discussion of qualitative research issues specifically in relation to nutrition and dietetics. This review, the first in a series, outlines the field of qualitative enquiry, its potential usefulness in nutrition and dietetics, and how to embark upon this type of research. Furthermore, it describes a process to guide high‐quality qualitative research in this area that proceeds from the research question(s) and considers the key philosophical assumptions about ontology, epistemology and methodology that underpin the overall design of a study. Other reviews in this series provide an overview of the principal techniques of data collection and sampling, data analysis, and quality assessment of qualitative work, and provide some practical advice relevant to nutrition and dietetics, along with glossaries of key terms.
Signal peptide‐regulated toxicity of a plant ribosome‐inactivating protein during cell stress
Authors: Marshall Richard S. , D’Avila Francesca , Di Cola Alessandra , Traini Roberta , Spanò Laura , Fabbrini Maria Serena , Ceriotti Aldo
Published: October 2010

The fate of the type I ribosome‐inactivating protein (RIP) saporin when initially targeted to the endoplasmic reticulum (ER) in tobacco protoplasts has been examined. We find that saporin expression causes a marked decrease in protein synthesis, indicating that a fraction of the toxin reaches the cytosol and inactivates tobacco ribosomes. We determined that saporin is largely secreted but some is retained intracellularly, most likely in a vacuolar compartment, thus behaving very differently from the prototype RIP ricin A chain. We also find that the signal peptide can interfere with the catalytic activity of saporin when the protein fails to be targeted to the ER membrane, and that saporin toxicity undergoes signal sequence‐specific regulation when the host cell is subjected to ER stress. Replacement of the saporin signal peptide with that of the ER chaperone BiP reduces saporin toxicity and makes it independent of cell stress. We propose that this stress‐induced toxicity may have a role in pathogen defence.
Identification of legume RopGEF gene families and characterization of a Medicago truncatula RopGEF mediating polar growth of root hairs
Authors: Riely Brendan K. , He Hengbin , Venkateshwaran Muthusubramanian , Sarma Birinchi , Schraiber Joshua , Ané Jean‐Michel , Cook Douglas R.
Published: October 2010

Root hairs play important roles in the interaction of plants with their environment. Root hairs anchor the plant in the soil, facilitate nutrient uptake from the rhizosphere, and participate in symbiotic plant–microbe interactions. These specialized cells grow in a polar fashion which gives rise to their elongated shape, a process mediated in part by a family of small GTPases known as Rops. RopGEFs (GEF, guanine nucleotide exchange factor) activate Rops to effect tip growth in Arabidopsis pollen and root hairs, but the genes mediating tip growth in legumes have not yet been characterized. In this report we describe the Rop and RopGEF gene families from the model legume Medicago truncatula and from the crop legume soybean. We find that one member of the M. truncatula gene family, MtRopGEF2, is required for root hair development because silencing this gene by RNA interference affects the cytosolic Ca2+ gradient and subcellular structure of root hairs, and reduces root hair growth. Consistent with its role in polar growth, we find that a GFP::MtRopGEF2 fusion protein localizes in the apex of emerging and actively growing root hairs. The amino terminus of MtRopGEF2 regulates its ability to interact with MtRops in yeast, and regulates its biological activity in vivo.
Vapyrin, a gene essential for intracellular progression of arbuscular mycorrhizal symbiosis, is also essential for infection by rhizobia in the nodule symbiosis of Medicago truncatula
Authors: Murray Jeremy D. , Muni RajaSekhara Reddy Duvvuru , Torres‐Jerez Ivone , Tang Yuhong , Allen Stacy , Andriankaja Megan , Li Guangming , Laxmi Ashverya , Cheng Xiaofei , Wen Jiangqi , Vaughan David , Schultze Michael , Sun Jongho , Charpentier Myriam , Oldroyd Giles , Tadege Million , Ratet Pascal , Mysore Kirankumar S. , Chen Rujin , Udvardi Michael K.
Published: October 2010

Intracellular invasion of root cells is required for the establishment of successful endosymbioses in legumes of both arbuscular mycorrhizal (AM) fungi and rhizobial bacteria. In both interactions a requirement for successful entry is the activation of a common signalling pathway that includes five genes required to generate calcium oscillations and two genes required for the perception of the calcium response. Recently, it has been discovered that in Medicago truncatula, the Vapyrin (VPY) gene is essential for the establishment of the arbuscular mycorrhizal symbiosis. Here, we show by analyses of mutants that the same gene is also required for rhizobial colonization and nodulation. VPY encodes a protein featuring a Major Sperm Protein domain, typically featured on proteins involved in membrane trafficking and biogenesis, and a series of ankyrin repeats. Plants mutated in this gene have abnormal rhizobial infection threads and fewer nodules, and in the case of interactions with AM fungi, epidermal penetration defects and aborted arbuscule formation. Calcium spiking in root hairs in response to supplied Nod factors is intact in the vpy‐1 mutant. This, and the elevation of VPY transcripts upon application of Nod factors which we show to be dependent on NFP, DMI1, and DMI3, indicates that VPY acts downstream of the common signalling pathway.
OsPUB15, an E3 ubiquitin ligase, functions to reduce cellular oxidative stress during seedling establishment
Authors: Park Jong‐Jin , Yi Jakyung , Yoon Jinmi , Cho Lae‐Hyeon , Ping Jin , Jeong Hee Joong , Cho Seok Keun , Kim Woo Taek , An Gynheung
Published: October 2010

The plant U‐box (PUB) protein functions as an E3 ligase to poly‐ubiquitinate a target protein for its degradation or post‐translational modification. Here, we report functional roles for OsPUB15, which encodes a cytosolic U‐box protein in the class‐II PUB family. Self‐ubiquitination assays showed that bacterially expressed MBP‐OsPUB15 protein has E3 ubiquitin ligase activity. A T‐DNA insertional mutation in OsPUB15 caused severe growth retardation and a seedling‐lethal phenotype. Mutant seeds did not produce primary roots, and their shoot development was significantly delayed. Transgenic plants expressing the OsPUB15 antisense transcript phenocopied these mutant characters. The abnormal phenotypes were partially rescued by two antioxidants, catechin and ascorbic acid. Germinating seeds in the dark also recovered the rootless defect. Levels of H2O2 and oxidized proteins were higher in the knock‐out mutant compared with the wild type. OsPUB15 transcript levels were increased upon H2O2, salt and drought stresses; plants overexpressing the gene grew better than the wild type under high salinity. These results indicate that PUB15 is a regulator that reduces reactive oxygen species (ROS) stress and cell death.
Measurement of cellular cGMP in plant cells and tissues using the endogenous fluorescent reporter FlincG
Authors: Isner Jean‐Charles , Maathuis Frans J. M.
Published: October 2010

The cyclic nucleotide cGMP has been shown to play important roles in plant development and responses to abiotic and biotic stress. To date, the techniques that are available to measure cGMP in plants are limited by low spatial and temporal resolution. In addition, tissue destruction is necessary. To circumvent these drawbacks we have used the δ‐FlincG fluorescent protein to create an endogenous cGMP sensor that can report cellular cGMP levels with high resolution in time and space in living plant cells. δ‐FlincG in transient and stably expressing cells shows a dissociation constant for cGMP of around 200 nm giving it a dynamic range of around 20–2000 nm. Stimuli that were previously shown to alter cGMP in plant cells (nitric oxide and gibberrellic acid) evoked pronounced fluorescence signals in single cells and in root tissues, providing evidence that δ‐FlincG reports changes in cellular cGMP in a physiologically relevant context.
Dorsal hippocampal opioidergic system modulates anxiety‐like behaviors in adult male Wistar rats
Authors: Solati Jalal , Zarrindast Mohammad‐Reza , Salari Ali‐Akbar
Published: October 2010

Aims: In the present study, we investigated the possible influence of the opioidergic system of the dorsal hippocampus on anxiety‐like behaviors.

Methods: Elevated plus‐maze, which is one of the methods used for testing anxiety, was used in the present study. Rats were anesthetized with ketamine and xylazine and special cannulas were inserted stereotaxically into the CA1 region of the dorsal hippocampus. After 1 week of recovery, the effects of intra‐CA1 administration of morphine (0.25, 0.5, 1 and 2 µg/rat; 1 µl/rat; 0.5 µl/in each side), naloxone (2, 4, 6 and 8 µg/rat), enkephalin (1, 2, 5 and 10 µg/rat) and naltrindole (0.25, 0.5, 1 and 2 µg/rat) on percentage open arm time (%OAT) and percentage open arm entries (%OAE) were determined.

Results: Bilateral administration of morphine into CA1 decreases %OAT and %OAE, indicating an anxiogenic‐like effect. Intra‐CA1 injection of naloxone, an opioid receptor antagonist, increased both %OAT and %OAE, parameters of anxiolytic‐like behavior. Bilateral administration of δ‐opioid receptor agonist, [D‐Pen2,5]‐enkephalin acetate hydrate into the CA1, induced an anxiolytic‐like effect. Furthermore, intra‐CA1 injection of δ‐opioid receptor antagonist, naltrindole hydrochloride, increased anxiety‐related behaviors.

Conclusions: The results of the present study demonstrate that activation of μ‐opioid receptors in this area produce an anxiogenic response while activation of δ‐opioid receptors produces an anxiolytic response.
Serum ghrelin is inversely associated with cognitive function in a sample of non‐demented elderly
Authors: Spitznagel Mary Beth , Benitez Andreana , Updegraff John , Potter Vanessa , Alexander Thomas , Glickman Ellen , Gunstad John
Published: October 2010

Aim:  The orexigenic hormone, ghrelin, is linked to learning and memory in animal studies. No previous study has investigated whether cognition is related to ghrelin in the non‐demented elderly.

Methods:  Thirty‐five older adults underwent neuropsychological testing and fasting blood draw with subsequent serum ghrelin quantification.

Results:  Ghrelin was negatively correlated with several cognitive domains, including verbal memory, working memory, and naming.

Conclusion:  Areas of cognition associated with ghrelin level were similar to the pattern of deficits observed in early Alzheimer's disease. Findings suggest a potential moderational role of ghrelin in pathological cognitive decline. Further work investigating mechanisms is needed.
From body‐talk to body‐stories: body work in complementary and alternative medicine
Authors: Gale Nicola Kay
Published: October 2010

This paper explores the ‘body work’ undertaken by practitioners of complementary and alternative medicine (CAM), in the light of ethnographic research on the education of osteopaths and homeopaths. The data presented focus on practitioners’ experiences of learning to communicate, touch and facilitate the healing process for their patients. Two new concepts are introduced: listening to body‐talk and constructing body‐stories, which are discussed as aspects of body work. Body‐talk expresses the idea that the embodied patient is not a passive recipient of healthcare, but that the ‘body’ is able to communicate its distress and its needs. The body‐story concept highlights the interactional nature of the therapeutic encounter and the profound interrelation between the treatment and case‐taking aspects of the practitioner’s clinical tasks. By drawing on key sociological concepts of the body and embodiment, reflexivity and narrative, I argue that the dialogical construction of body‐stories challenges Cartesian dualism. Finally, I discuss what the data might mean for the future development of the sociological concept of ‘body work’, drawing particular attention to the necessity to problematise the concept of the ‘body’ and to pay great attention to body work as embodied work.
Do Hospitals Alter Patient Care Effort Allocations under Pay‐for‐Performance?
Authors: Nicholas Lauren Hersch , Dimick Justin B. , Iwashyna Theodore J.
Published: October 2010

Objective. To determine whether hospitals increase efforts on easy tasks relative to difficult tasks to improve scores under pay‐for‐performance (P4P) incentives.

Data Source. The Centers for Medicare and Medicaid Services Hospital Compare data from Fiscal Years 2003 through 2005 and 2003 American Hospital Association Annual Survey data.

Study Design. We classified measures of process compliance targeted by the Premier Hospital Quality Incentive Demonstration as easy or difficult to improve based on whether they introduce additional per‐patient costs. We compared process compliance on easy and difficult tasks at hospitals eligible for P4P bonus payments relative to hospitals engaged in public reporting using random effects regression models.

Principal Findings. P4P hospitals did not preferentially increase efforts for easy tasks in patients with heart failure or pneumonia, but they did exhibit modestly greater effort on easy tasks for heart attack admissions. There is no systematic evidence that effort was allocated toward easier processes of care and away from more difficult tasks.

Conclusions. Despite perverse P4P incentives to change allocation of efforts across tasks to maximize performance scores at lowest cost, we find little evidence that hospitals respond to P4P incentives as hypothesized. Alternative incentive structures may motivate greater response by targeted hospitals.
Relationship between P‐Wave Duration and Atrial Electromechanical Delay Assessed by Tissue Doppler Echocardiography
Authors: DĄBROWSKA‐KUGACKA ALICJA , LEWICKA‐NOWAK EWA , RUCIŃSKI PIOTR , ZAGOŻDŻON PAWEŁ , RACZAK GRZEGORZ , KUTARSKI ANDRZEJ
Published: October 2010

Background: The aim of the study was to assess the relationship between P‐wave duration on the surface electrocardiogram (ECG) and echocardiographic parameters of atrial electromechanical delay (EMD), as well as contraction synchrony during different atrial pacing modalities.

Methods: In 57 patients with sinus node disease and prolonged sinus P‐wave duration treated with multisite atrial pacing (MSAp), the EMD was measured by tissue Doppler in several left and right atrial sites during sinus rhythm, MSAp, and single‐site pacing at right atrial appendage (RAAp), Bachmann's bundle (BBp) region, and coronary sinus (CSp) ostium. Regional atrial synchrony was calculated on the basis of EMD.

Results: P‐wave duration was 141 ± 16, 120 ± 17, 138 ± 17, 144 ± 16, and 160 ± 19 ms during sinus rhythm, MSAp, BBp, CSp, and RAAp, respectively (P < 0.001 RAAp and MSAp vs other). P‐wave duration correlated with all atrial EMDs as well as interatrial and intraleft atrial parameters of dyssynchrony. In multivariate analysis, the EMD in lateral left atrial wall was the strongest predictor of P‐wave duration (β 0.41; P < 0.001). The relationship between P‐wave duration and the atrial EMDs was most prominent during RAAp (all left atrial walls r > 0.51; P < 0.01) and BBp (all atrial walls r > 0.42; P < 0.05), while during sinus rhythm and CSp, only weak correlation between echo and ECG was found. Neither of the tissue Doppler parameters correlated with P‐wave duration during MSAp. Interatrial dyssynchrony correlated with P‐wave duration during sinus rhythm and RAAp and intraleft atrial dyssynchrony only during sinus rhythm.

Conclusions: P‐wave duration of the surface ECG is highly correlated with the atrial EMD, the relationship is specific for each pacing modality. (PACE 2011; 23–31)
Sialoadenitis secondary to 131I therapy for well‐differentiated thyroid cancer
Authors: Van Nostrand D
Published: October 2010

Oral Diseases (2011) 17, 154–161

Radioiodine (131I) is an important therapy for patients who have well‐differentiated thyroid cancer. However, 131I may also result in side effects in multiple organs and glands. The glands that are frequently affected are the salivary glands with the major untoward effects including sialoadenitis and increased risk of second primary malignancy. This report will review sialoadenitis secondary to 131I therapy including (1) proposed mechanisms, (2) incidence and clinical presentations, (3) possible approaches to improve prevention, (4) management, and (5) sequelae of sialoadenitis (e.g. xerostomia and salivary duct obstruction). A discussion of second primary malignancies is beyond the scope of this review. With a better understanding of the above, dentists, oral surgeons, otolaryngologists, endocrinologists, nuclear medicine physicians, and nuclear radiologists will be more likely to implement more effective preventive measures to reduce the incidence and severity of 131I‐induced sialoadenitis, and if it does occur, to identify and treat sialoadenitis sooner, thereby potentially reducing not only the severity of the initial symptoms, but also the severity of subsequent sequelae.
HIV infection and periodontal diseases: an overview of the post‐HAART era
Authors: Mataftsi M , Skoura L , Sakellari D
Published: October 2010

Oral Diseases (2010) 17, 13–25

HIV infection remains a global health problem of unprecedented dimensions, although the development of highly active antiretroviral therapy (HAART) has significantly modified the course of HIV disease into a manageable chronic disease with longer survival and improved quality of life in HIV‐infected subjects. Among the HIV‐associated infections, oral lesions have been recognized as prominent features since the beginning of the epidemic and continue to be important. Periodontal diseases strongly associated with HIV infection are classified as linear gingival erythema, necrotizing ulcerative gingivitis and necrotizing ulcerative periodontitis and are included among the cardinal oral lesions. Although oral candidiasis appears to be the infection more significantly decreased after the introduction of HAART, the current literature suggests that the prevalence and course of periodontal lesions have also been modified. Higher prevalence of opportunistic microorganisms has been frequently detected in the subgingival flora of HIV‐infected individuals, probably due to the immune status of those patients, as colonization and overgrowth of atypical pathogenic species is facilitated by immunosuppression. Additional research is required regarding biological issues such as the role of oral immune factors and periodontal disease in the persistency of HIV infection, the possibility of oral transmission and the re‐emerging of HIV infection.
Root and periodontal tissue development after allogenic tooth transplantation between rat littermates
Authors: Andou K , Nakamura M , Ina Y , Sasaki K , Sasano Y
Published: October 2010

Oral Diseases (2011) 17, 379–386

Objective:  The study was designed to investigate the development of roots and periodontal tissues after allogenic tooth transplantation between rat littermates by micro‐computed tomography (micro‐CT) and histology.

Materials and Methods:  The upper right second molars in 2‐week‐old rats were extracted and immediately transplanted into the upper right first molar socket of rat littermates under anesthesia. The upper left second molars in 2‐week‐old recipient rats were used as a control. The rats were fixed and tissues analyzed at 0, 4, 8, or 12 weeks after transplantation. Root development of seven rats in each group was analyzed quantitatively using micro‐CT. Periodontal tissue formation was examined qualitatively by histologic methods.

Results:  Roots developed after allogenic transplantation, but they were significantly shorter than control roots. The number of roots varied from one to four in transplanted teeth, while it was consistently four in control teeth. Periodontal tissue formation in transplanted teeth was equivalent to that of the control teeth.

Conclusion:  Allogenic transplantation between rat littermates permits root development and periodontal tissue formation.
Cheilitis glandularis: clinico‐histopathological diagnostic criteria
Authors: Reiter S , Vered M , Yarom N , Goldsmith C , Gorsky M
Published: October 2010

Oral Diseases (2011)17, 335–339

Objectives: To present a combination of clinical and histopathological criteria for diagnosing cheilitis glandularis (CG), and to evaluate the association between CG and squamous cell carcinoma (SCC).

Materials and Methods: The medical literature in English was searched from 1950 to 2010 and selected demographic data, and clinical and histopathological features of CG were retrieved and analysed.

Results: A total of 77 cases have been published and four new cases were added to the collective data. The clinical criteria applied included the coexistence of multiple lesions and mucoid/purulent discharge, while the histopathological criteria included two or more of the following findings: sialectasia, chronic inflammation, mucous/oncocytic metaplasia and mucin in ducts. Only 47 (58.0%) cases involving patients with a mean age of 48.5 ± 20.3 years and a male‐to‐female ratio of 2.9:1 fulfilled the criteria. The lower lip alone was most commonly affected (70.2%). CG was associated with SCC in only three cases (3.5%) for which there was a clear aetiological factor for the malignancy.

Conclusions: The proposed diagnostic criteria can assist in delineating true CG from a variety of lesions with a comparable clinical/histopathological presentation. CG in association with premalignant/malignant epithelial changes of the lower lip may represent secondary, reactive changes of the salivary glands.
Employee voice and value during a period of economic turbulence
Authors: Gollan Paul J. , Perkins Stephen J.
Published: October 2010

Themes emerging at conference events held at the London School of Economics on 20 March 2009 and 26 March 2010
How Terminology and Definitions in Analytical Geochemistry can Help or Hinder the Development of New Ideas
Authors: Ramsey Michael H.
Published: October 2010

Refining terminology can help the development of new concepts. For example, the definition of the terms bias and precision for the two types of measurement error were useful in the early development of data quality in analytical chemistry. The more recent recognition of uncertainty of measurement has aided the development of further new ideas, such as the fitness‐for‐purpose of measurements. The wording of the definition of each term needs to be clear and understandable, as well as rigorous, if it is to enable new ideas to be explained to both the research community and to the users of measurements. However, some definitions are identified as cryptic and ambiguous. This inhibits the development of new ideas, and leads to misunderstanding and confusion amongst researchers, students and the wider user community. One possible solution is to have one formal definition that is technically rigorous, and ideally, but not necessarily, widely comprehensible. A second informal definition could also be made that is widely comprehensibility, whilst being consistent with the formal definition. An increased level of discussion and debate is required in the measurement community to resolve the underlying philosophical issues that cause some of the ambiguity in the description of the measurement process. For example, there is a choice to be made between the statistical and the metrological approaches, which result in use of the concepts of either the true value of the analyte concentration, or the measurand.
The genus Bolboschoenus in Iran: taxonomy and distribution
Authors: Amini Rad Mohammad , Hroudová Zdenka , Marhold Karol
Published: October 2010

A revision of the Iranian Bolboschoenus was made based on studies of herbarium material and cultivated plants. Fruit features (fruit shape and pericarp anatomy) were used as the main distinguishing characters; style branching, inflorescence structure and the colour of floral scales were considered as accompanying distinguishing characters. The following taxa were recognized: Bolboschoenus glaucus (Lam.) S. G. Sm., B. affinis (Roth) Drobov, B. schmidii (Raymond) Holub, B. planiculmis (F. Schmidt) T. V. Egorova and B. maritimus (L.) Palla. Taxonomical difficulties, especially in the B. affinis group and B. maritimus are discussed. Bolboschoenus glaucus was found in all of the phytogeographical regions of Iran, and it is more frequent than any other Bolboschoenus species. Bolboschoenus planiculmis is very rare in the Irano–Turanian and Hyrcanian regions and grows only in human‐influenced habitats; it might be introduced as a weed in rice fields. Bolboschoenus maritimus, B. affinis and B. schmidii occur in the Irano–Turanian region only rarely. Bolboschoenus maritimus reaches the southeastern border of its distribution area in this region. All these species typically grow at higher altitudes. Great morphological variability in inflorescence structure was found in some species (especially in B. glaucus), which may be partly explained as a response to habitat conditions and partly by genotypic diversity.
Chirita leprosa sp. nov. (Gesneriaceae) from limestone areas in Guangxi, China
Authors: Xu Wei‐Bin , Pan Bo , Huang Yu‐Song , Liu Yan
Published: October 2010

Chirita leprosa Yan Liu & W. B. Xu, a new species of Gesneriaceae from Guangxi, China, is described and illustrated. The new species is similar to C. wangiana Z. Y. Li, but differs by the leaf blade being elliptic to broadly elliptic, bracts broadly ovate, corolla pale yellow, filaments ca 9 mm long, geniculate near the middle, staminodes 3, and by a different flowering period (Oct–Nov).
Oberonia swaminathanii sp. nov. (Orchidaceae) from Kerala, India
Authors: Narayanan M. K. Ratheesh , Manudev K. M. , Sujanapal P. , Kumar N. Anil , Sivadasan M. , Alfarhan Ahmed H.
Published: October 2010

Oberonia swaminathanii, a new species of Orchidaceae from Wayanad district, Kerala, India is described and illustrated. The new species resembles Oberonia balakrishnanii, O. chandrasekharanii and O. seidenfadeniana by its 3‐lobed labellum and 2‐lobuled midlobe; but differs in having brick‐red coloured flowers, triangular labellum disc, and a subglobose column.
Efficient Computational Model for Nonaxisymmetric Flow and Heat Transfer in Rotating Cavity
Authors: He L.
Published: October 2010

Existence of large scale unsteady flow structures manifested in contrarotating vortex pairs has been previously identified in rotor disk cavities. The nonaxisymmetric nature with an unknown number of vortices presents a computational challenge, as a full 360 deg circumferential domain will be needed, requiring significant computational resources. A novel circumferential spatial Fourier spectral technique is adopted in the present work to facilitate efficient computational predictions of the nonaxisymmetric flows. Given that the flow nonuniformities in the circumferential direction are of large length scales, only a few circumferential Fourier harmonics would be needed, resulting in a drastic reduction in number of circumferential mesh points to be required. The modeling formulations and implementation aspects will be described. Computational examples will be presented to demonstrate the validity and effectiveness of the present modeling approach. The computational results show that the nonaxisymmetric flow patterns, in terms of the number of vortex pairs, are sensitive to small scale external disturbances. It is also indicated that the occurrence of a nonaxisymmetric flow might be captured by the present Fourier solution with even one harmonic.
Heat Transfer in Rotating Channel With Inclined Pin-Fins
Authors: Park Jun Su , Kim Kyung Min , Lee Dong Hyun , Cho Hyung Hee , Chyu Minking
Published: October 2010

This study is to examine experimentally the effects of pin inclination and pin height-to-diameter ratio on the heat/mass transfer characteristics in a pin-fin channel with and without rotation. The test model consists of staggered pin-fin arrays with an interpin spacing of 2.5 times of the pin-diameter (S/D=2.5) in both longitudinal and transverse directions. Detailed local heat/mass transfer coefficients on the two principal surfaces of rotating channel are measured using the naphthalene sublimation technique. The inclined angles (θ) studied are 60 deg and 90 deg. The pin height-to-diameter ratio (Hp/Dp) ranges from 2 to 4. The Reynolds number is fixed at 7.0×103 with two rotation numbers (0.0 and 0.2). The measured data show that the overall array heat/mass transfer decreases with the angle of inclination relative to the vertical orientation. The overall array averaged as well as the row-resolved heat/mass transfer increases with an increase in Hp/Dp. Rotation generally results in higher heat/mass transfer than the corresponding stationary case. The nonuniformity or redistribution of heat/mass transfer induced by the Coriolis force generally perceived in a ribbed or smooth channel is less evident in a pin-fin channel.
Performance Improvement of a Centrifugal Compressor Stage by Increasing Degree of Reaction and Optimizing Blade Loading of a 3D Impeller
Authors: Shibata Takanori , Yagi Manabu , Nishida Hideo , Kobayashi Hiromi , Tanaka Masanori
Published: October 2010

Performance improvement of 3D impellers in a high specific speed range was investigated using computational fluid dynamics analyses and experimental tests. In order to reduce the loss production within the stator passages, the backsweep angle of the impellers was increased. At the same time, the inlet-to-exit relative velocity diffusion ratio was also increased by increasing the impeller exit width to prevent the reduction in the pressure ratio. Moreover, the blade loading distribution at the impeller shroud side was optimized to suppress the surge margin reduction caused by the increased relative velocity diffusion ratio. Five types of unshrouded impellers were designed, manufactured, and tested to evaluate the effects of blade loading, backsweep angle, and relative velocity diffusion ratio on the compressor performance. The design suction flow coefficient was 0.125 and the machine Mach number was 0.87. Test results showed that the compressor stage efficiency was increased by 5% compared with the base design without reducing the pressure coefficient and surge margin. It was concluded that an increased relative velocity diffusion ratio coupled with large backsweep angle was a very effective way to improve the compressor stage efficiency. An appropriate blade loading distribution was also important in order to achieve a wide operating range as well as high efficiency.
Pulse Performance Modeling of a Twin Entry Turbocharger Turbine Under Full and Unequal Admission
Authors: Costall Aaron W. , McDavid Robert M. , Martinez-Botas Ricardo F. , Baines Nicholas C.
Published: October 2010

The pulsating nature of gas flow within the exhaust manifold of an internal combustion engine is not well captured by the quasi-steady techniques typically employed by cycle simulation programs for turbocharger modeling. This problem is compounded by the unequal admission conditions imposed on the turbine by the use of multiple entry housings installed as standard on pulse turbocharged diesel engines. This unsteady behavior presents the simulation engineer with a unique set of difficulties when modeling turbocharger turbines. It is common for experienced analysts to accommodate multiple entries by splitting the flow across duplicate components and by tuning the level of interference between volute entries but this necessarily bespoke approach is limited to upstream modifications that cannot capture true turbine unsteady operation. This paper describes recent simulation code development work undertaken at Caterpillar to improve machine submodel accuracy essential for virtual product development meeting U.S. nonroad Tier 4 emission standards. The resulting turbine performance model has been validated against experimental data for a twin entry turbocharger suitable for heavy duty nonroad applications, obtained using a permanent magnet eddy-current dynamometer and pulse flow test facility. Comparison between experiment and prediction demonstrates good agreement under full admission in terms of both instantaneous flow capacity and turbine actual power although unequal admission results indicate the need for further model development.
Film Cooling
Effectiveness Measurements With Periodic Unsteady Inflow on Highly Loaded Blades With Main Flow
Separation
Authors: Gomes Reinaldo
A. , Niehuis Reinhard
Published: October 2010

Film cooling experiments were performed using a highly loaded high pressure turbine blade blade linear cascade. A large region with main flow separation is found on the pressure side and film cooling is provided into this area with three rows of either cylindrical or fan-shaped holes. The measurements comprise adiabatic film cooling effectiveness and profile static pressure measurements. The surface temperature was acquired with thermochromatic liquid crystals and using a hue to temperature correlation. The results shown are for variations in main flow Mach and Reynolds numbers at engine relevant levels and of coolant mass flows. The results for steady and periodic unsteady inflows with highly turbulent wakes created by cylindrical bars moving upstream in a plane parallel to the cascade are compared as two-dimensional surface plots, laterally averaged film cooling effectiveness and overall effectiveness over the entire surface.
Effects of Simulated Particle Deposition on Film Cooling
Authors: Lawson S. A. , Thole K. A.
Published: October 2010

Diminishing natural gas resources has increased incentive to develop cleaner, more efficient combined-cycle power plants capable of burning alternative fuels such as coal-derived synthesis gas (syngas). Although syngas is typically filtered, particulate matter still exists in the hot gas path that has proven to be detrimental to the life of turbine components. Solid and molten particles deposit on film-cooled surfaces that can alter cooling dynamics and block cooling holes. To gain an understanding of the effects that particle deposits have on film cooling, a methodology was developed to simulate deposition in a low speed wind tunnel using a low melt wax, which can simulate solid and molten phases. A facility was constructed to simulate particle deposition on a flat plate with a row of film cooling holes. Infrared thermography was used to measure wall temperatures for quantifying spatially resolved adiabatic effectiveness values in the vicinity of the film cooling holes as deposition occurred. Results showed that deposition reduced cooling effectiveness by approximately 20% at momentum flux ratios of 0.23 and 0.5 and only 6% at a momentum flux ratio of 0.95.
Influence of Rim Seal Purge Flow on the Performance of an Endwall-Profiled Axial Turbine
Authors: Schuepbach P. , Abhari R. S. , Rose M. G. , Gier J.
Published: October 2010

Nonaxisymmetric endwall profiling is a promising method to reduce secondary losses in axial turbines. However, in high-pressure turbines, a small amount of air is ejected at the hub rim seal to prevent the ingestion of hot gases into the cavity between the stator and the rotor disk. This rim seal purge flow has a strong influence on the development of the hub secondary flow structures. This paper presents time-resolved experimental and computational data for a one-and-1/2-stage high work axial turbine, showing the influence of purge flow on the performance of two different nonaxisymmetric endwalls and the axisymmetric baseline case. The experimental total-to-total efficiency assessment reveals that the nonaxisymmetric endwalls lose some of their benefit relative to the baseline case when purge is increased. The first endwall design loses 50% of the efficiency improvement seen with low suction, while the second endwall design exhibits a 34% deterioration. The time-resolved computations show that the rotor dominates the static pressure field at the rim seal exit when purge flow is present. Therefore, the purge flow establishes itself as jets emerging at the blade suction side corner. The jet strength is modulated by the first vane pressure field. The jets introduce circumferential vorticity as they enter the annulus. As the injected fluid is turned around the rotor leading edge, a streamwise vortex component is created. The dominating leakage vortex has the same sense of rotation as the rotor hub passage vortex. The first endwall design causes the strongest circumferential variation in the rim seal exit static pressure field. Therefore, the jets are stronger with this geometry and introduce more vorticity than the other two cases. As a consequence the experimental data at the rotor exit shows the greatest unsteadiness within the rotor hub passage with the first endwall design.
Effect of Scaling of Blade Row Sectors on the Prediction of Aerodynamic Forcing in a Highly Loaded Transonic Compressor Stage
Authors: Mayorca María A. , De Andrade Jesús A. , Vogt Damian M. , Mårtensson Hans , Fransson Torsten H.
Published: October 2010

An investigation of the sensitivity of a geometrical scaling technique on the blade forcing prediction and mode excitability has been performed. A stage of a transonic compressor is employed as a test object. A scaling ratio is defined, which indicates the amount of scaling from the original geometry. Different scaling ratios are selected and 3D Navier–Stokes unsteady calculations completed for each scaled configuration. A full-annulus calculation (nonscaled) is performed serving as reference. The quantity of interest is the generalized force, which gives a direct indication of the mode excitability. In order to capture both up- and downstream excitation effects, the mode excitability has been assessed on both rotor and stator blades. The results show that the first harmonic excitation can be predicted well for both up- and downstream excitations using moderate amounts of scaling. On the other hand, the predictions of second harmonic quantities do show a higher sensitivity to scaling for the investigated test case.
Experimental Investigation on the Effects of Unsteady Excitation Frequency of Casing Treatment on Transonic Compressor Performance
Authors: Tuo Wei , Lu Yajun , Yuan Wei , Zhou Sheng , Li Qiushi
Published: October 2010

The importance of the unsteady effects between the casing treatment and rotor is still not clear. Experiments are conducted in a transonic compressor with arc skewed slot casing treatment configurations. The experimental results indicate that the unsteady excitation frequency due to the slot number of casing treatment is one of the most important factors influencing compressor performance. Also, compressor performance can be overall enhanced through optimizing this unsteady excitation frequency. For the transonic compressor herein, peak efficiency, stall margin, and maximum flow mass can be improved by 0.17%, 19.86%, and 0.81%, respectively, at near design rotating speed, which can reach up to 1.13%, 57.84%, and 1.57%, respectively, at part design speed.
Analysis of Gas Turbine Rotating Cavities by a One-Dimensional Model: Definition of New Disk Friction Coefficient Correlations Set
Authors: Da Soghe Riccardo , Facchini Bruno , Innocenti Luca , Micio Mirko
Published: October 2010

Reliable design of a secondary air system is one of the main tasks for the safety and unfailing performance of gas turbine engines. To meet the increasing demands of gas turbine designs, improved tools in the prediction of secondary air system behavior over a wide range of operating conditions are needed. A real gas turbine secondary air system includes several components, therefore, its analysis is not carried out through a complete computational fluid dynamics (CFD) approach. Usually, those predictions are performed using codes based on simplified approach, which allows to evaluate the flow characteristics in each branch of the air system requiring very poor computational resources and few calculation time. Generally, the available simplified commercial packages allow to correctly solve only some of the components of a real air system, and often, the elements with a more complex flow structure cannot be studied; among such elements, the analysis of rotating cavities is very hard. This paper deals with a design tool developed at the University of Florence for the simulation of rotating cavities. This simplified in-house code solves the governing equations for steady one-dimensional axisymmetric flow using experimental correlations, both to incorporate the flow phenomena caused by multidimensional effects such as heat transfer and flow field losses, and to evaluate the circumferential component of velocity. Although this calculation approach does not enable a correct modeling of the turbulent flow within a wheel space cavity, the authors tried to create an accurate model, taking into account the effects of inner and outer flow extraction, rotor and stator drag, leakages, injection momentum, and finally, the shroud/rim seal effects on cavity ingestion. The simplified calculation tool was designed to simulate the flow in a rotating cavity with radial outflow, both with the Batchelor and/or Stewartson flow structures. A primary 1D-code testing campaign is available in the literature (2008, “Analysis of Gas Turbine Rotating Cavities by a One-Dimensional Model,” ISROMAC Paper No. 12-2008-20161). In the present paper, the authors developed, using CFD tools, reliable correlations for both stator and rotor friction coefficients and provided a full 1D-code validation, due to the lack of experimental data, comparing the in-house design-code predictions with those evaluated by CFD.