bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies in neotropical Apocynaceae XL: synopsis of the genus Prestonia (Apocynoideae, Echiteae) in Ecuador
Authors: Morales J. Francisco
Published: July 2010

A synopsis of the genus Prestonia (Apocynaceae, Apocynoideae, Echiteae) in Ecuador is presented and 15 species are reported. A key to species, distributional data, discussion of relationships, and representative specimen citations for each province are provided. An illustration of the enigmatic P. schumanniana Woodson, known only from the type collection, is also included. Prestonia purpurissata Woodson, P. phenax Woodson, P. peregrina Woodson y P. vallis Woodson are reduced to the synonymy of P. annularis (L. f.) G. Don and Echites pallidus Miers to the synonymy of P. mollis Kunth. Lectotypes are designated for Haemadictyon tomentellum Benth., Prestonia phenax Woodson, and P. plumierifolia Markgr. A neotype is designated for P. vallis Woodson.
A new species of Astragalus L. sect. Sesamei DC. (Leguminosae) from the southeast of Spain: Astragalus castroviejoi
Authors: Talavera Lozano Salvador , Sánchez-Gómez Pedro , López García David , Jiménez Martínez Juan Francisco , Mota Poveda Juan Francisco
Published: July 2010

We describe a new species of Astragalus section Sesamei from the semiarid zone of SE Spain: Astragalus castroviejoi. Morphologically the new species resembles A. sesameus L. and A. stella L. and we provide a key to distinguish the three species. A. castroviejoi is a diploid species with 2n = 16, the same chromosome number as A. sesameus and A. stella. We provide an image of the karyotype, together with an illustration of the new species and a map of its distribution. Since the existing populations are restricted in area, we also provide an estimate of the conservartion status of this species according to the criteria of the IUCN.
Spinal Cord Pathology in Alpha-Synuclein Transgenic Mice
Authors: Mendritzki Sonja , Schmidt Saskia , Sczepan Teresa , Zhu Xin-Ran , Segelcke Daniel , Lübbert Hermann
Published: July 2010

Accumulation ofα-synuclein is observed in neurodegenerative diseases like Parkinson's disease and Multiple System Atrophy. In previous studies with transgenic C57BL/6 mice overexpressingα-synuclein carrying the mutations A53T and A30P found in Parkinson's disease or with a parkin-null background, we reported severe mitochondrial impairments in neurons and to a larger extent in glial cells of the mesencephalon. Neuron death was not observed in the brain. Here we show that the mice show severe motor impairments in behavioral tests. In addition, these mice exhibit astrocytic cell death in the spinal cord, accompanied by extensive gliosis and microglial activation. This is shown by cell death staining and immunohistochemistry. Ultrastructural analyses revealed severe mitochondrial impairments not only in astrocytes, but also in oligodendrocytes and, to a small extent, in neurons. Thus, the transgenic mice show a profound pathology in glial cells of the spinal cord.
Lessons from Multicenter Studies on CSF Biomarkers for Alzheimer's Disease
Authors: Mattsson Niklas , Zetterberg Henrik , Blennow kaj
Published: July 2010

Several single-center studies have confirmed the usability of cerebrospinal fluid (CSF) biomarkers for the diagnosis of Alzheimer's disease (AD), even in early disease stages. Large scale multicenter studies have principally confirmed this, although such studies have also indicated the presence of significant intercenter and interlaboratory variations in biomarker measurements. Such variations may hamper the development of biomarkers and their introduction into clinical routine practice. Recently a quality control program run by the Alzheimer's Association was started in order to harmonize procedures of laboratories world-wide. This program provides both standardized guide lines and external control CSF samples, and will allow longitudinal evaluation of laboratory performance.
Study of bone mineral density in resident doctors working at a teaching hospital
Authors: Multani SK , Sarathi V , Shivane V , Bandgar TR , Menon PS , Shah NS
Published: July 2010

Context:

The erratic lifestyle of resident doctors may affect their serum 25-hydroxy vitamin D [25-(OH)D] levels and bone mineral density (BMD).

Aim:

To study BMD and the effect of environmental factors on it in resident doctors.

Settings and Design:

Prospective, cross-sectional study conducted in a tertiary healthcare centre.

Materials and Methods:

BMD was obtained by dual-energy X-ray absorptiometry and was correlated with various factors including weight, height, body mass index (BMI), sun exposure, physical activity, parathyroid hormone, 25-(OH)D, dietary factors.

Statistical Analysis:

SPSS software Version 10 (Unpaired t test was used to compare BMD of different groups and Pearson's correlation coefficient was used to calculate correlation).

Results:

Two hundred and fourteen apparently healthy resident doctors were enrolled in the study. Based on Caucasian normative data, osteopenia was noted in 104 (59.7%) males and 27 (67.5%) females. Thirty-two (18.39%) males and five (12.5%) females had osteoporosis. The BMD values of males were 0.947±0.086, 0.911±0.129 and 1.016±0.133 at lumbar spine, femur neck and total hip while those in females were 0.981±0.092, 0.850±0.101 and 0.957±0.103 respectively. BMD of our cohort was lesser by 12.5-18.2% and 4.2-14.5% than the Caucasian and available Indian figures, respectively. BMD had significant positive correlation with weight, height, BMI, physical activity, and dietary calcium phosphorus ratio. 25-(OH)D levels were insufficient in 175 (87.5%) subjects but had no correlation with BMD.

Conclusions:

Young healthy resident doctors had significantly lower BMD, contributors being lower BMI, lower height, reduced bioavailability of dietary calcium and inadequate physical activity. Deficiency of vitamin D did not contribute to low BMD.
Pediatric imaging
Authors: Shenoy-Bhangle A , Nimkin K , Gee MS
Published: July 2010

Imaging has always been an important component of the clinical evaluation of pediatric patients. Rapid technological advances in imaging are making noninvasive evaluation of a wide range of pediatric diseases possible. Ultrasound and magnetic resonance imaging (MRI) are two imaging modalities that do not involve ionizing radiation and are preferred imaging modalities in the pediatric population. Computed tomography (CT) remains the imaging modality with the highest increase in utilization in children due to its widespread availability and rapid image acquisition. Emerging imaging applications to be discussed include MR urography, voiding urosonography with use of ultrasound contrast agents, CT dose reduction techniques, MR enterography for inflammatory bowel disease, and MR cine airway imaging.
Liposomal amphotericin B (FungisomeTM) for the treatment of cryptococcal meningitis in HIV/AIDS patients in India
Authors: Jadhav MP , Bamba A , Shinde VM , Gogtay N , Kshirsagar NA , Bichile LS , Mathai D , Sharma A , Varma S , Digumarathi R
Published: July 2010

Background:

There is need to investigate the use of liposomal amphotericin B in cryptococcal meningitis in India.

Aims:

To compare the efficacy, safety, duration of treatment and cost of two doses of liposomal amphotericin B (Amp B) (FungisomeTM) in cryptococcal meningitis in HIV/AIDS patients.

Settings and Design:

Prospective, randomized, multicenter study in tertiary care hospitals across India.

Materials and Methods:

Adult patients with culture-proven cryptococcal meningitis with HIV/AIDS were randomized to receive either 1 (Group A) or 3 mg/kg/day of Fungisome (Group B). Clinical efficacy and tolerability, laboratory evaluations and mycological response were assessed daily, twice weekly and weekly respectively. The patients were assessed at four and eight-week follow-up.

Statistics:

We calculated average and standard deviation for the various parameters.

Results:

The time to show clinical response was 13.66 days (1 mg) and 9.55 days (3 mg). In Group B (n=6 complete response), 50% patients responded within one week by microbial conversion, 83% in two weeks and 100% in three weeks. Patients with 1 mg dose (n=4 complete response), none showed microbial conversion within one week, 75% responded in two weeks, whereas one patient took four weeks. The average duration of treatment was 36.5±14.4 and 26.5±5.89 (S.D.) days in 1 and 3 mg/kg/day respectively. Drug was tolerated with little renal, hepatic or hematological toxicity. The cost was found to be 3.81 lacs and 1.74 lacs with 3mg/kg/day and 1mg/kg/day respectively.

Conclusion:

Higher dose showed better efficacy and quicker microbial conversion of Cerebrospinal fluid (CSF) (cerebrospinal fluid) than 1 mg/kg/day. It shortened the duration of treatment in days by 27% while drug cost almost doubled (Clinical trial registration number: ISRTCN 52812742)
Clinical profile of primary hyperparathyroidism from western India
Authors: Gopal RA , Acharya SV , Bandgar T , Menon PS , Dalvi AN , Shah NS
Published: July 2010

Background:

Primary hyperparathyroidism (PHPT) has a variable clinical presentation and symptomatic PHPT is still the predominant form of the disease in India. Data from western India is lacking.

Aim:

To present the clinical profile of PHPT from western India.

Settings and Design:

This retrospective study was conducted at a tertiary care referral center.

Materials and Methods:

We analyzed the clinical presentation, biochemical, radiological features, and operative findings in adult patients with PHPT (1986-2008) and compared with our published data of children and adolescent patients with PHPT.

Statistical Analysis:

was done with SPSS 16 software.

Results:

Seventy-nine patients (F: M-2:1) with age ranging from 21 to 55 years (mean 33.5±8.82) were analyzed. Skeletal manifestations (75.5%), renal calculi (40.5%) and proximal muscle weakness (45.5%) were the most common symptoms of presentation with mean duration of symptoms being 33.70 (median: 24, range 1-120) months. Biochemical features included hypercalcemia (total corrected calcium 12.55±1.77 mg/dl), low inorganic phosphorus (1.81±0.682 mg/dl), elevated total alkaline phosphatase (mean: 762.2; median: 559; range: 50-4930IU/L) and high parathyroid hormone (PTH) (mean±SD: 866.61±799.15; median: 639.5; range: 52-3820 pg/ml). Preoperative localization was achieved in 74 patients and single adenoma was found during surgery in 72 patients. Hungry bone disease was seen in 30.3% and transient hypoparathyroidism developed in 62% patients. In comparison to PHPT in children there were no significant differences with regard to clinical, laboratory and radiological features.

Conclusions:

PHPT in western India is symptomatic disorder with skeletal and renal mani-festations at a much younger age. Clinical profile of PHPT in children is similar to that of adults.
Current and emerging techniques in gastrointestinal imaging
Authors: McSweeney SE , O′Donoghue PM , Jhaveri K
Published: July 2010

This review is devoted to current and emerging techniques in gastrointestinal (GI) imaging. It is divided into three sections focusing on areas that are both interesting and challenging: imaging of the small bowel and appendix, imaging of the colon and rectum and finally liver and pancreas in the upper abdomen. The first section covers cross-sectional imaging of the small bowel using the techniques of multidetector computed tomography (MDCT) (including CT enterography) and magnetic resonance imaging (MRI). The evaluation of mesenteric ischemia and GI tract bleeding using MDCT angiography is also reviewed. Current imaging practice in the evaluation of appendix is also reviewed and illustrated. The second section reviews CT and MR colonography and imaging of the rectum. It describes CT virtual colonoscopy (CTVC) with emphasis on the advantages and disadvantages of the technique with discussion of the role of CTVC in screening. The intriguing topic of MR colonography (MRC) is also reviewed. Imaging of the rectum with emphasis on imaging of rectal cancer is described with the roles of CT, MR, endoluminal ultrasound and positron emission tomography scanning discussed. The final section reviews current and emerging techniques in liver imaging with the role of ultrasound including contrast ultrasound, MDCT and MR (including contrast agents) discussed. The new developments and applications of imaging of pancreatic disease are discussed with emphasis on the role of MDCT and MRI with gadolinium. This review highlights the current role and advancement of imaging techniques with new diagnostic and prognostic information pertinent to gastrointestinal disease continuing to emerge.
Magnetic resonance imaging
Authors: Sanghvi DA , Patel Z , Patankar T
Published: July 2010

Neuroimaging is presently utilised in clinical practice for initial diagnosis and mapping of disease extent and distribution, noninvasive, preoperative grading of tumours, biopsy planning, surgery and radiation portal planning for tumors, judging response to therapy and finally, prognostication. Newer advances include magnetic resonance (MR) diffusion and diffusion tensor imaging with tractography, perfusion imaging, MR spectroscopy and functional imaging using the blood oxygen level-dependent contrast technique. Neuroimaging plays a pivotal role in various degenerative and neoplastic diseases, improving diagnostic accuracy, affecting patient care, monitoring dynamic changes within the brain during therapy, and establishing them as the arbiter of novel therapy that may one day prove cure of various brain diseases a reality.
Gynecologic imaging
Authors: Iyer VR , Lee SI
Published: July 2010

Common diagnostic challenges in gynecology and the role of imaging in their evaluation are reviewed. Etiologies of abnormal uterine bleeding identified on pelvic sonography and sonohysterography are presented. An algorithmic approach for characterizing an incidentally detected adnexal mass and use of magnetic resonance imaging for definitive diagnosis are discussed. Finally, the role of F18-fluorodeoxyglucose positron emission tomography in the management of gynecological malignancies, and pitfalls associated with their use are examined.
Cardiac imaging
Authors: Jankharia B , Raut A
Published: July 2010

Cardiac magnetic resonance imaging (MRI) and computed tomography (CT) scan have made big inroads as modalities used for evaluation of various pathologies of the heart. Cardiac MRI is typically used for perfusion and viability studies as well as to study various cardiomyopathies, valvular diseases and the pericardium. It has been used in the evaluation of congenital heart diseases over the last two decades. Cardiac CT is used mainly for the evaluation of the coronary arteries, typically in the setting of "to rule out coronary artery disease".
The relationship between near‐surface turbulence and gas transfer velocity in freshwater systems and its implications for floating chamber measurements of gas exchange
Authors: Vachon Dominic , Prairie Yves T. , Cole Jonathan J.
Published: July 2010

We performed a series of gas exchange measurements in 12 diverse aquatic systems to develop the direct relationship between near‐surface turbulence and gas transfer velocity. The relationship was log‐linear, explained 78% of the variation in instantaneous gas transfer velocities, and was valid over a range of turbulent energy dissipation rates spanning about two orders of magnitude. Unlike wind‐based relationships, our model is applicable to systems ranging in size from less than 1 km2 to over 600 km2. Gas fluxes measured with our specific model of floating chambers can be grossly overestimated (by up to 1000%), particularly in low‐turbulence conditions. In high‐turbulence regimes, flux overestimation decreases to within 50%. Direct measurements of turbulent energy dissipation rate provide reliable estimation of the associated gas transfer velocity even at short temporal and spatial scales.
UV absorption cross sections of nitrous oxide (N2O) and carbon tetrachloride (CCl4) between 210 and 350 K and the atmospheric implications
Authors: Rontu Carlon N. , Papanastasiou D. K. , Fleming E. L. , Jackman C. H. , Newman P. A. , Burkholder J. B.
Published: July 2010

Abstract. Absorption cross sections of nitrous oxide (N2O) and carbon tetrachloride (CCl4) are reported at five atomic UV lines (184.95, 202.548, 206.200, 213.857, and 228.8 nm) at temperatures in the range 210–350 K. In addition, UV absorption spectra of CCl4 are reported between 200–235 nm as a function of temperature (225–350 K). The results from this work are critically compared with results from earlier studies. For N2O, the present results are in good agreement with the current JPL recommendation enabling a reduction in the estimated uncertainty in the N2O atmospheric photolysis rate. For CCl4, the present cross section results are systematically greater than the current recommendation at the reduced temperatures most relevant to stratospheric photolysis. The new cross sections result in a 5–7% increase in the modeled CCl4 photolysis loss, and a slight decrease in the stratospheric lifetime, from 51 to 50 years, for present day conditions. The corresponding changes in modeled inorganic chlorine and ozone in the stratosphere are quite small. A CCl4 cross section parameterization for use in atmospheric model calculations is presented.
Regional-scale geostatistical inverse modeling of North American CO2 fluxes: a synthetic data study
Authors: Gourdji S. M. , Hirsch A. I. , Mueller K. L. , Yadav V. , Andrews A. E. , Michalak A. M.
Published: July 2010

Abstract. A series of synthetic data experiments is performed to investigate the ability of a regional atmospheric inversion to estimate grid-scale CO2 fluxes during the growing season over North America. The inversions are performed within a geostatistical framework without the use of any prior flux estimates or auxiliary variables, in order to focus on the atmospheric constraint provided by the nine towers collecting continuous, calibrated CO2 measurements in 2004. Using synthetic measurements and their associated concentration footprints, flux and model-data mismatch covariance parameters are first optimized, and then fluxes and their uncertainties are estimated at three different temporal resolutions. These temporal resolutions, which include a four-day average, a four-day-average diurnal cycle with 3-hourly increments, and 3-hourly fluxes, are chosen to help assess the impact of temporal aggregation errors on the estimated fluxes and covariance parameters. Estimating fluxes at a temporal resolution that can adjust the diurnal variability is found to be critical both for recovering covariance parameters directly from the atmospheric data, and for inferring accurate ecoregion-scale fluxes. Accounting for both spatial and temporal a priori covariance in the flux distribution is also found to be necessary for recovering accurate a posteriori uncertainty bounds on the estimated fluxes. Overall, the results suggest that even a fairly sparse network of 9 towers collecting continuous CO2 measurements across the continent, used with no auxiliary information or prior estimates of the flux distribution in time or space, can be used to infer relatively accurate monthly ecoregion scale CO2 surface fluxes over North America within estimated uncertainty bounds. Simulated random transport error is shown to decrease the quality of flux estimates in under-constrained areas at the ecoregion scale, although the uncertainty bounds remain realistic. While these synthetic data inversions do not consider all potential issues associated with using actual measurement data, e.g. systematic transport errors or problems with the boundary conditions, they help to highlight the impact of inversion setup choices, and help to provide a baseline set of CO2 fluxes for comparison with estimates from future real-data inversions.
Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry
Authors: Lockwood A. L. , Shepson P. B. , Fiddler M. N. , Alaghmand M.
Published: July 2010

Abstract. Isoprene is an important atmospheric volatile organic compound involved in ozone production and NOx (NO+NO2) sequestration and transport. Isoprene reaction with OH in the presence of NO can form either isoprene hydroxy nitrates ("isoprene nitrates") or convert NO to NO2 which can photolyze to form ozone. While it has been shown that isoprene nitrate production can represent an important sink for NOx in forest impacted environments, there is little experimental knowledge of the relative importance of the individual isoprene nitrate isomers, each of which has a different fate and reactivity. In this work, we have identified the 8 individual isomers and determined their total and individual production yields. The overall yield of isoprene nitrates at atmospheric pressure and 295 K was found to be 0.070(+0.025/−0.015). Three isomers, representing nitrates resulting from OH addition to a terminal carbon, represent 90% of the total IN yield. We also determined the ozone rate constants for three of the isomers, and have calculated their atmospheric lifetimes, which range from ~1–2 h, making their oxidation products likely more important as atmospheric organic nitrates and sinks for nitrogen.
Two-dimensional performance of MIPAS observation modes in the upper-troposphere/lower-stratosphere
Authors: Carlotti M. , Papandrea E. , Castelli E.
Published: July 2010

Abstract. In this paper we analyze the performance of the three MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) observation modes that sound the Upper-Troposphere/Lower-Stratosphere (UT/LS) region. The two-dimensional (2-D) tomographic retrieval approach is assumed to derive the atmospheric field of geophysical parameters. For each observation mode we have calculated the 2-D distribution of the information load quantifier relative to the main MIPAS targets. The performance of the observation modes is then evaluated in terms of strength, spatial coverage and uniformity of the information-load distribution along the full orbit. The outcome of the information-load analysis has been validated with simulated retrievals based on the observational parameters of real orbits. With this strategy we have assessed the precision and the spatial (both horizontal and vertical) resolution of the retrieval products. The performance of the three observation modes has been compared for the MIPAS main products in both the UT/LS and the extended altitude range. This study shows that the two observation modes that were specifically designed for the UT/LS region are actually competitive with the third one, designed for the whole stratosphere, up to altitudes that far exceed the UT/LS. In the UT/LS the performance of the two specific observation modes is comparable even if the best performance in terms of horizontal resolution is provided by the observation mode that was excluded by the European Space Agency (ESA) from the current MIPAS duty cycle. This paper reports the first application of the information-load analysis and highlights the validity of this approach.
Satellite observations reveal high variability and a decreasing trend in CO2 fluxes on the Scotian Shelf
Authors: Shadwick E. H. , Thomas H. , Comeau A. , Craig S. E. , Hunt C. W. , Salisbury J. E.
Published: July 2010

Abstract. We develop an algorithm to compute pCO2 in the Scotian Shelf region (NW Atlantic) from satellite-based estimates of chlorophyll-a concentration, sea-surface temperature, and observed wind speed. This algorithm is based on a high-resolution time-series of pCO2 observations from an autonomous mooring. At the mooring location (44.3° N and 63.3° W), the surface waters act as a source of CO2 to the atmosphere over the annual scale, with an outgassing of −1.1 mol C m−2 yr−1 in 2007/2008. A hindcast of air-sea CO2 fluxes from 1999 to 2008 reveals significant variability both spatially and from year to year. Over the decade, the shelf-wide annual air-sea fluxes range from an outgassing of −1.7 mol C m−2 yr−1 in 2002, to −0.02 mol C m−2 yr−1 in 2006. There is a gradient in the air-sea CO2 flux between the northeastern Cabot Strait region which acts as a net sink of CO2 with an annual uptake of 0.5 to 1.0 mol C m−2 yr−1, and the southwestern Gulf of Maine region which acts as a source ranging from −0.8 to −2.5 mol C m−2 yr−1. There is a decline, or a negative trend, in the air-sea pCO2 gradient of 23 μatm over the decade, which can be explained by a cooling of 1.3 °C over the same period. Regional conditions govern spatial, seasonal, and interannual variability on the Scotian Shelf, while multi-annual trends appear linked to the North Atlantic Oscillation.
EPOCA/EUR-OCEANS data compilation on the biological and biogeochemical responses to ocean acidification
Authors: Nisumaa A.-M. , Pesant S. , Bellerby R. G. J. , Delille B. , Middelburg J. J. , Orr J. C. , Riebesell U. , Tyrrell T. , Wolf-Gladrow D. , Gattuso J.-P.
Published: July 2010

Abstract. The uptake of anthropogenic CO2 by the oceans has led to a rise in the oceanic partial pressure of CO2, and to a decrease in pH and carbonate ion concentration. This modification of the marine carbonate system is referred to as ocean acidification. Numerous papers report the effects of ocean acidification on marine organisms and communities but few have provided details concerning full carbonate chemistry and complementary observations. Additionally, carbonate system variables are often reported in different units, calculated using different sets of dissociation constants and on different pH scales. Hence the direct comparison of experimental results has been problematic and often misleading. The need was identified to (1) gather data on carbonate chemistry, biological and biogeochemical properties, and other ancillary data from published experimental data, (2) transform the information into common framework, and (3) make data freely available. The present paper is the outcome of an effort to integrate ocean carbonate chemistry data from the literature which has been supported by the European Network of Excellence for Ocean Ecosystems Analysis (EUR-OCEANS) and the European Project on Ocean Acidification (EPOCA). A total of 185 papers were identified, 100 contained enough information to readily compute carbonate chemistry variables, and 81 data sets were archived at PANGAEA – The Publishing Network for Geoscientific & Environmental Data. This data compilation is regularly updated as an ongoing mission of EPOCA. Data access: http://doi.pangaea.de/10.1594/PANGAEA.735138
Hydrological effects of the temporal variability of the multiscaling of snowfall on the Canadian prairies
Authors: Shook K. R. , Pomeroy J. W.
Published: July 2010

Abstract. Daily historical snowfall data were analysed with the objective of determining the stability of their variability at short temporal scales. The data are weakly multifractal over periods shorter than one month, which controls their scaling properties and which can be used to statistically downscale monthly data to shorter-duration values. Although the daily snowfall values appear to be stationary, their multifractality displays much temporal variability, with most sites showing statistically-significant trends. Through use of a physically-based hydrological model, it is demonstrated that the variability of the multiscaling of snowfall can affect the timing and quantity of snow accumulation in catchments where the snowpacks are subject to wind redistribution. Therefore trends in scaling, based on multifractal characteristics, should be taken into account when downscaling climate model scenario outputs.
The Uto‐Aztecan premolar among North and South Amerindians: Geographic variation and genetics
Authors: Delgado‐Burbano Miguel E. , Scott G. Richard , Turner Christy G.
Published: July 2010

The Uto‐Aztecan premolar (UAP) is a dental polymorphism characterized by an exaggerated distobuccal rotation of the paracone in combination with the presence of a fossa at the intersection of the distal occlusal ridge and distal marginal ridge of upper first premolars. This trait is important because, unlike other dental variants, it has been found exclusively in Native American populations. However, the trait's temporal and geographic variation has never been fully documented. The discovery of a Uto‐Aztecan premolar in a prehistoric skeletal series from northern South America calls into question the presumed linguistic and geographic limits of this trait. We examined published and unpublished data for this rare but highly distinctive trait in samples representing over 5,000 Native Americans from North and South America. Our findings in living Southwest Amerindian populations corroborate the notion that the variable goes beyond the bounds of the Uto‐Aztecan language family. It is found in prehistoric Native Americans from South America, eastern North America, Northern and Central Mexico, and in living and prehistoric populations in the American Southwest that are not members of the Uto‐Aztecan language stock. The chronology of samples, its geographic distribution, and trait frequencies suggests a North American origin (Southwest) for UAP perhaps between 15,000 BP and 4,000 BP and a rapid and widespread dispersal into South America during the late Holocene. Family data indicate that it may represent an autosomal recessive mutation that occurred after the peopling of the Americas as its geographic range appears to be limited to North and South Amerindian populations. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.
Gellan–adipic acid blends crosslinked by means of a dehydrothermal treatment
Authors: Barbani Niccoletta , Coluccio Maria Laura , Cristallini Caterina , Guerra Giulio D. , Rosellini Elisabetta
Published: July 2010

Blends of gellan gum (GE) and adipic acid (ADA), at various ratios, were manufactured in the form of films by casting from aqueous solutions and crosslinked by a dehydrothermal treatment (DHT). The materials, before and after DHT, were characterized by both physicochemical tests and cellular adhesion and growth on the film surfaces. The total reflection and spotlight Fourier transform infrared (FTIR) spectroscopy and optical and scanning electron microscopy showed the presence of both GE‐rich and ADA‐rich regions and the formation of ester groups after DHT. Differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis (DMA) showed that the crosslinking by DHT made the materials more thermally stable. The swelling in water, which diminished in the films subjected to DHT, confirmed that the crosslinking enhanced the whole stability of the material. DMA also showed that the behavior of the GE–ADA blends was quite similar to that of some living tissues, such as the skin. The cell cultures indicated that the materials, especially that with a 6 : 10 ADA‐to‐GE ratio, were very able to promote cellular adhesion and proliferation. In conclusion, the GE–ADA crosslinked blends appeared very suitable for a use as biomaterials; in particular, the cell cultures indicated that they might be useful as scaffolds for tissue reconstruction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structural changes induced by the deamidation and isomerization of asparagine revealed by the crystal structure of Ustilago sphaerogena ribonuclease U2B
Authors: Noguchi Shuji
Published: July 2010

Under physiological conditions, the deamidation and isomerization of asparagine to isoaspartate (isoAsp) proceeds nonenzymatically via succinimide. Although a large number of proteins have been reported to contain isoAsp, information concerning the three‐dimensional structure of proteins containing isoaspartate is still limited. We have crystallized isoAsp containing Ustilago sphaerogena ribonuclease U2B, and determined the crystal structure at 1.32 Å resolution. The structure revealed that the formation of isoAsp32 induces a single turn unfolding of the α‐helix from Asp29 to Asp34, and the region from Asp29 to Arg35 forms a U‐shaped loop structure. The electron density map shows that isoAsp32 retained the L‐configuration at the Cα atom. IsoAsp32 is in gauche conformation about a CαCβ bond, and the polypeptide chain bends by ∼90° at isoAsp32. IsoAsp32 protrudes from the surface of the protein, and the abnormal β‐peptide bond in the main‐chain and α‐carboxylate in the side‐chain is fully exposed. The structure suggests that the deamidation of the Asn and the isoAsp formation in proteins could confer immunogenicity. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 1003–1010, 2010.
Hindered settling in non‐newtonian power law liquids
Authors: Chhabra R. P. , Unnikrishnan A. , Nair V. R. Unnikrishnan
Published: July 2010

New experimental results on the hindered settling of model glass bead suspensions in non‐Newtonian suspending media are reported. The data presented encompass the following ranges of variables: 7.38 × 10−4 ≤ Re1∞ ≤ 2; 0.0083 ≤ d/D ≤ 0.0703; 0.13 ≤ C ≤ 0.43 and 1 ≥ n ≥ 0.8. In these ranges of conditions, the dependence of the hindered settling velocity on concentration is adequately represented by the corresponding Newtonian expressions available in the literature. The influence of the power law flow behaviour index is completely embodied in the modified definition of the Reynolds number used for power law liquids.
CFD Simulation of Solids Suspension in Mixing Vessels
Authors: Kee Nicholas C. S. , Tan Reginald B. H.
Published: July 2010

A CFD approach for predicting minimum impeller speed (Njs) to achieve complete off‐bottom solids suspension in mechanically‐agitated vessels is presented. The method is based on observing the simulated transient profiles of solids volume fraction for the layer of cells adjacent to the vessel floor and has been shown to be reliable and robust. Predicted Njs values for typical impeller systems were compared with well‐known empirical correlations and good agreement was obtained.
Concept for Scale‐up of Solids Suspension in Stirred Tanks
Authors: Kraume Matthias , Zehner Peter
Published: July 2010

A relationship describing the suspension of particulate solids in a propeller loop reactor is derived and applied by analogy to the corresponding process in stirred tanks. According to this equation, the ratio of minimum power input for suspension to settling power under the conditions of laminar flow, is inversely proportional to the tank diameter. In contrast, the power ratio remains constant for fully turbulent flow. The observations presented explain the fact that numerous authors have reported various scale‐up rules which range between these two extremes. The scale‐up procedure is demonstrated for a 21 m3 full‐scale tank.
Tracer Dispersion in Stirred Tank Reactors: Asymptotic Properties and Mixing Characterization
Authors: Giona Massimiliano , Paglianti Alessandro , Cerbelli Stefano , Pintus Sandro , Adrover Alessandra
Published: July 2010

This article addresses the characterization of dispersion and homogenization phenomena in stirred vessels through the analysis of dispersion curves that can be obtained experimentally by means of conductivity measurements. New insights on mixing conditions can be achieved from the analysis of the qualitative and asymptotic properties of tracer dispersion curves. The results obtained are interpreted in the context of the spectral approach to the advection‐diffusion equation. It is shown that any flow model aimed at reproducing the experimentally determined dispersion curves must be at least two‐dimensional. Convection‐enhanced dispersion associated with the spectral structure of the advection‐diffusion equation is addressed.
Assessing the Performance of Model Predictive Controllers
Authors: Patwardhan Rohit S. , Shah Sirish L. , Qi Kent Z.
Published: July 2010

Performance assessment of model predictive controllers is a problem of significant industrial relevance. Model predictive controllers belong to a class of linear time‐varying controllers, which compute the future control actions by minimizing a constrained, time‐varying objective function. In this work we propose a performance statistic that takes into account the time‐varying and constrained nature of model predictive control. The proposed measure compares the achieved objective function with its design value, online. Analytical expressions are derived to calculate the expected value of the design objective function under closed loop conditions. Simulation and industrial case studies are used to illustrate the applicability of the proposed metric.
Interrelations between Rheology and Phase Behaviour in Partially Miscible Blends: The Case of Polydimethylsiloxane/Polyethylmethylsiloxane (PDMS/PEMS)
Authors: Chopra Divya , Kontopoulou Marianna , Vlassopoulos Dimitris , Hatzikiriakos Savvas G.
Published: July 2010

A rheological study of the phase behaviour and the dynamics in the immiscible region of a model partially miscible Upper Critical Solution Temperature (UCST) blend was carried out by using a series of nearly monodisperse polydimethylsiloxane (PDMS) of varying molecular weights blended with polyethylmethylsiloxane (PEMS). The complete phase diagram was established through steady shear rheology, optical microscopy and light scattering. The UCST, interfacial tension and morphology of these blends are very sensitive to the molecular weight of the constituents. Partial miscibility was observed only when the Mw of PDMS was sufficiently low. The viscoelastic behaviour in the phase separated region can be modeled successfully using the Palierne model.
Stagnation‐point Flow towards a Stretching Surface
Authors: Mahapatra Tapas R. , Gupta Anadi S.
Published: July 2010

An exact similarity solution of the Navier‐Stokes equations is obtained. The solution represents steady axisymmetric stagnation‐point flow towards a stretching surface. It is shown that the flow displays a boundary‐layer structure when the stretching velocity of the surface is less than the free stream velocity. On the other hand, an inverted boundary layer is formed when the surface stretching velocity exceeds the free stream velocity. Temperature distribution in the flow is found when the surface is held at a constant temperature. It turns out that when the surface temperature exceeds the ambient temperature, heat flows from the surface to the fluid near the stagnation point but further away from the stagnation point, heat flows from the fluid to the stretching surface.
Hydrogen Production from Partial Oxidation and Steam Reforming of N‐octane Over Alumina‐supported Ni and Ni‐Pd Catalysts
Authors: Zhang Jinchang , Wang Yanhui , Wu Diyong
Published: July 2010

Hydrogen production by partial oxidation and steam reforming (POSR) of n‐octane was investigated over alumina‐supported Ni and Ni‐Pd catalysts. It showed that Ni‐Pd/Al2O3had higher activity and hydrogen selectivity than the nickel catalyst under the experimental conditions, which indicated Ni‐Pd/Al2O3could be an effective catalyst for the production of hydrogen from hydrocarbons.
Mixing in Bubble Column Reactors: Role of Unsteady Flow Structures
Authors: Buwa Vivek V. , Ranade Vivek V.
Published: July 2010

Gas‐liquid flows in bubble column reactors are inherently unsteady. In the present work, we have characterized dynamics of gas‐liquid flow in rectangular bubble columns and studied the role of unsteady flow structures in liquid phase mixing using experiments and CFD simulations. The need for considering the unsteady nature of gas‐liquid flows was demonstrated by using mixing simulations carried out with transient and time‐averaged flow. A new methodology of using a computationally amenable 'multiple snapshots' approach, which can adequately account for dynamics of underlying flow, is proposed. CFD simulations were carried out to study the influence of superficial gas velocity and height‐to‐width ratio on mixing time. The predictions were compared with mixing time measured using conductivity probes. The present work gives useful insights into the mixing process in inherently unsteady flows.
Dynamics of Bubble Growth and Detachment from Rigid and Flexible Orifices
Authors: Loubière Karine , Hébrard Gilles , Guiraud Pascal
Published: July 2010

The objective of this paper is to understand how and why the orifice nature (rigid or flexible) governs bubble generation. The differences in orifice nature and properties have strong consequences on the bubbles generated. Indeed, the dynamics of the formation and the nature of the detached bubbles are fundamentally different depending on whether the bubbles are generated from the rigid orifice or from the flexible orifice.
Performance of Multi‐Plunging Jet Absorber Using Liquid Jets Containing Small Solute Bubbles
Authors: Ide Mitsuharu , Uchiyama Hiroki , Ishikura Toshifumi
Published: July 2010

The effects of structural factors in nozzles having a gas sucking type bubble generator and the number of nozzles for a multi‐plunging jet absorber using liquid jets containing small solute bubbles on gas‐liquid interfacial area and mass transfer were investigated. It was found that the volumetric liquid phase mass transfer coefficient (kLa)T of the absorber increased with increasing nozzle number. The mass transfer performance of this absorber was comparable to that of other high performance gas‐liquid contacting devices. A two‐region model was found to be applicable to the mechanism of liquid phase mass transfer in the multi‐plunging jet absorber.
Intensification of Slurry Bubble Columns by Vibration Excitement
Authors: Ellenberger Jürg , Krishna Rajamani
Published: July 2010

We show that application of low‐frequency vibrations, in the 30 to 60 Hz range, to the liquid phase of an air — water — silica catalyst slurry bubble column causes significant enhancement of both gas holdup and volumetric mass transfer coefficient over a wide range of superficial gas velocities. The increase in the gas holdup is attributed mainly to a significant reduction in the rise velocity of the bubble swarm due to the generation of standing waves in the column. Furthermore, application of vibrations to the liquid phase serves to stabilize the homogenous bubbly flow regime and delay the onset of the churn‐turbulent flow regime.
Modelling of Gas‐Liquid/Gas‐Liquid‐Solid Flows in Bubble Columns: Experiments and CFD Simulations
Authors: Rampure Mohan R. , Buwa Vivek V. , Ranade Vivek V.
Published: July 2010

Gas‐liquid/gas‐liquid‐solid systems are widely used in the chemical process industry for a variety of applications. In the present work, we have characterized the dynamics of gas‐liquid/gas‐liquid‐solid flows in cylindrical bubble columns using experiments and CFD simulations. The low frequency oscillations corresponding to the local re‐circulatory flow were characterized using wall pressure fluctuation measurements. Eulerian‐Eulerian two‐/three‐phase simulations were carried out with a focus on characterizing the dynamic properties of gas‐liquid/gas‐liquid‐solid flows. The effects of superficial gas velocity,H/Dratio and solid loading on the dynamic and time‐averaged flow behavior were studied experimentally and computationally. The simulated results were compared with the experimental measurements. The results presented are useful for understanding the dynamics of gas‐liquid/gas‐liquid‐solid flows in bubble columns and provide a basis for further development of CFD models for three‐phase systems.
Liquid Distribution and RTD in Trickle Bed Reactors: Experiments and CFD Simulations
Authors: Gunjal Prashant R. , Ranade Vivek V. , Chaudhari Raghunath V.
Published: July 2010

Hydrodynamics and mixing in trickle bed reactors (TBR) are governed by bed porosity, capillary forces, wetting and non‐uniform distribution at the inlet. In this work, experiments were carried out to study pressure drop, liquid hold‐up and residence time distribution for pre‐wetted and non‐wetted bed. CFD models were developed, in which bed heterogeneity and capillary models were incorporated. Mixing and RTD were simulated using the CFD model. This study was further extended to study the flow mal‐distribution in TBR. Based on these results, current capabilities and limitations of the CFD model were discussed. The model and the results discussed here would be useful to extend application of CFD models for simulating mixing in TBR.
Catalysis of Gas Hydrates by Biosurfactants in Seawater‐Saturated Sand/Clay
Authors: Rogers Rudy E. , Kothapalli Chandra , Lee May S. , Woolsey J Robert
Published: July 2010

Biosurfactants catalyzed natural gas hydrate formation in sand/clay packs saturated with seawater. Representative samples from the five possible biosurfactant classifications enhanced hydrate formation rate and decreased hydrate induction time. Biosurfactants increased rates 96% to 288% and decreased induction times 20% to 71% relative to the control. Micellar‐forming rhamnolipid reached a critical micellar concentration at 13 ppm at hydrate‐forming conditions; these micelles migrated readily through a seawater‐saturated sand pack to catalyze hydrate formation in another zone. The type of biosurfactant, in conjunction with specific porous media, help determine massive, dispersed, nodular, or stratified forms of hydrates. Results suggested that minimal microbial activity in ocean‐floor sands can greatly influence gas hydrate formation.
Convergence Promotion in the Wang‐Henke Tridiagonal Matrix Method
Authors: Monroy‐Loperena Rosendo , Flores‐Sánchez Patricia
Published: July 2010

In this work, a modification to the well known and extensively used Tridiagonal Matrix Method, proposed since 1966 by Wang and Henke (1966), for simulating vapour‐liquid multi‐stage distillation problems is proposed for promoting the convergence of the original iterative process. The modification, which involves the incorporation of Broyden's method for accelerating convergence based on adjustment of the tear variables, solves the vapour‐liquid multi‐stage distillation problems in a more efficient way. Two promotion schemes are proposed, one uses as the tear variables the temperature and vapour flow profiles and the other uses only the temperature profile. The two promotion schemes are compared to the original iteration scheme proposed by Wang and Henke. Results are reported for distillation and reboiled‐absorption processes.
Non‐Linear Predictive Control of a Three‐Phase Catalytic Reactor
Authors: Costa Aline C. , Filho Rubens Maciel
Published: July 2010

In this work, the predictive control of a three‐phase catalytic reactor is considered. A predictive control algorithm, which has a non‐linear internal model represented by functional link networks, is proposed. This network structure has been shown to have a good non‐linear approximation capability, with the advantage that the estimation of its weight is a linear optimization problem. The results show the potential of the proposed procedure when it is applied to the 2‐methyl‐cyclohexanol production process, which is a non‐linear, distributed parameter and time‐varying process, typical of many important industrial systems.
Hydrocyclone Performance with Complex Oil‐Water Emulsions in the Feed
Authors: Belaidi Abdelhafid , Thew Martin T. , Munaweera Sampath J.
Published: July 2010

Separation performance of an oil‐water hydrocyclone depends very much on the physical properties of the feed emulsion or dispersion. These properties can be influenced by numerous factors, particularly water cut and the type of emulsion.In this exploratory work, the effects of water cut and flowrate on de‐watering capabilities of a hydrocyclone with a complex emulsion in the feed line are investigated. Two flow rates of 25 and 35L/min were studied and the water cut was varied from about 8 to 65%. For each case separation, efficiency was measured, the emulsion characterized and its stability checked for the three hydrocyclone streams. Drop size distribution was also examined. Comparison of performance with a simple emulsion was also made.
Synthesis and Analysis of Triphenylamine: A Review
Authors: Manifar Touraj , Rohani Sohrab
Published: July 2010

In this paper, synthesis and characteristic of arylamine‐type molecules, particularly triphenylamine are discussed. An overview of the physical properties and chemical characteristics of these types of molecules is provided. Different synthesis methods and mechanisms involved for the production of these molecules and their analysis byHPLCare presented. Finally, a brief note about their purification is presented.