bluuebunny/crossref_metadata_2025 huggingface dataset:
Airborne remote sensing for detection of irrigation canal leakage
Authors: Huang Yanbo , Fipps Guy , Maas Stephan J. , Fletcher Reginald S.
Published: May 2009

Traditional field survey methods for detection of water leaks in irrigation canal systems are costly and time‐ consuming. In this study, a rapid, cost‐effective method was developed for identifying irrigation canal locations likely to have leaks and/or seepage. The method involves the use of a multispectral imager equipped with red, near infrared, and thermal sensors which is mounted on an aircraft and flown at low altitude to collect the images. A three‐step process, image acquisition, image processing, and field reconnaissance, was developed for processing the imagery and identification of locations likely to have leaks. The method was evaluated in the Lower Rio Grande Valley of Texas, USA. Images were collected of 24 selected canal segments within 11 irrigation districts in this region. Evaluation of the imagery indicated that 140 sites had possible canal leakage problems (point leak and/or seepage). A field site evaluation form was developed and used to document the type and severity of the leaks at 28 of the sites. Twenty‐six sites were confirmed to have leaks, representing a success rate of 93%. The methods used in this study should have widespread application for detecting leaks and seepage in irrigation canals. Copyright © 2009 John Wiley & Sons, Ltd.
Phytoplankton and Epipelon Responses to Clear and Turbid Phases in a Seepage Lake (Buenos Aires, Argentina)
Authors: Casco María Adela , Mac Donagh María Elicia , Cano María Gabriela , Solari Lía Cristina , Claps María Cristina , Gabellone Néstor Adrián
Published: May 2009

Annual changes in the algal density and concentrations of chlorophyll a, total phosphorus, and organic matter were analyzed in water and sediments at four sites characterized by the presence or absence of submerged and emergent macrophytes, during turbid‐ and clear‐water conditions to determine the contribution of the algal components of the plankton and the epipelon and to identify the most typical species in each community. Three states were recognized: one turbid and two clear, with different submerged macrophyte cover. The peaks of phytoplankton and epipelon occurred in the turbid phase, whereas the highest proportion of true epipelic algae in sediments was reached in the second clear phase. The Oscillatoriaceae dominated during the turbid phase in the water and throughout the entire year within the sediments. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Morphometric and Preliminary Genetic Characteristics of Artemia Populations from Iran
Authors: Agh Naser , Bossier Peter , Abatzopoulos Theodore J. , Beardmore John A. , Stappen Gilbert Van , Mohammadyari Ali , Rahimian Hasan , Sorgeloos Patrick
Published: May 2009

Six Artemia populations, one bisexual and five parthenogenetic, from different parts of Iran were compared using morphometric and genetic characteristics. The discriminant analysis based on 19 morphometric variables showed that there are significant differences between the studied populations based on their morphological characteristics, where 85.9% of original grouped cases were correctly classified. The bisexual Artemia urmiana however exhibited a 100% separation from the parthenogenetic populations. However, a 1500 bp mitochondrial rDNA fragment showed similar RFLP patterns for all Iranian populations confirming earlier reports of a close genetic relationship between A. urmiana and parthenogenetic Artemia. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Desiccation and Sediment Type on Early Regeneration of Plant Fragments of Three Species of Aquatic Macrophytes
Authors: Silveira Márcio José , Thomaz Sidinei Magela , Mormul Roger Paulo , Camacho Franciele Pereira
Published: May 2009

We tested the effects of desiccation and type of sediment (clay or sand) on the regeneration of fragments of the apical shoots of three species of Hydrocharitaceae: Egeria najas, E. densa and Hydrilla verticillata. The shoots were left to dry on clay or sand from zero to four days, and were then returned to aquaria containing water. To approximate natural conditions, the aquaria containing clay had higher turbidity and nutrient (P and N) concentrations than did the aquaria with sand. All species dried faster on sand substrate, which led to lower regeneration (in terms of dry weight, length, sprout and root formation) in this treatment. H. verticillata fragments elongated faster than the other species, but E. najas was the most successful species (in terms of increase in dry weight) in the sand treatment. Our results indicate that the exotic H. verticillata has a competitive advantage, at least in its early stages of regeneration, over the other two, native species, especially in more eutrophic and turbid habitats; whereas E. najas fragments have a competitive advantage in less‐turbid, oligotrophic and sand‐dominated sites. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultraviolet Insights: Attempting to Resolve Enigmatic Patterns in Pelagic Freshwaters – The Historical Context and a View to the Future
Authors: Williamson Craig E. , Rose Kevin C.
Published: May 2009

While great advances have been made in our understanding of pelagic freshwater communities and ecosystems in recent years, several unexplained patterns continue to evade our understanding. While no single factor can explain these enigmatic patterns, recent increases in our understanding of the ecology of ultraviolet radiation (UV) are consistent with UV playing an important role. Here we present a brief overview of why UV has historically received so little attention in pelagic freshwater ecosystems, review some of the important aspects of the ecology of UV that are important to these enigmatic patterns, and discuss how this new understanding of the ecology of UV may provide some insights into these previously unexplained patterns. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Phylogenetic Analysis of Ilyocryptus Sars, 1862 (Cladocera: Ilyocryptidae)
Authors: Kotov Alexey A. , Elías‐Gutiérrez Manuel
Published: May 2009

Kotov and Štifter (2006) revised the taxonomy of the genus Ilyocryptus Sars, 1862 (Branchiopoda: Anomopoda: Ilyocryptidae) and concluded that 28 species can be recognized as valid for the world fauna. In order to test phylogenetic relationships between the species and to contribute to a better understanding of the genus, a cladistic (using branch‐and‐bound search) analysis was conducted for 25 Ilyocryptus species (two of them with two subspecies). In total, 32 morphological characters were used. An evolutionary‐morphological interpretation of the results was also made. Phylogenetic analysis revealed that Ilyocryptus elegans is an earlier derived member of the genus, while other species are separated into two main branches: agilis ‐ and sordidus ‐lines (without reference to type of moulting). Species with incomplete moulting and species with complete moulting do not form separate clusters, suggesting an independent origin of incomplete moulting within different species groups. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Small Dams on the Benthic Community of Streams in an Atlantic Forest Area of Southeastern Brazil
Authors: Almeida Erick Frota , Oliveira Renata Bley , Mugnai Riccardo , Nessimian Jorge Luiz , Baptista Darcílio Fernandes
Published: May 2009

We examined the effects of longitudinal discontinuity in small rivers, produced by the construction of small dams, on the macroinvertebrate communities in a biological reserve in southeastern Brazil. Two regulated streams were sampled in the rainy and dry seasons at three sites along the river. One site was upstream of the dam/abstraction and two were below the dam. Our results indicate that there was a difference in the communities between the dry and rainy periods even though water physicochemical parameters of the water were not significantly different. The biotic richness at sites 500 m below the dam were similar to those above the impoundment (control), indicating that the fauna recovered when the discharge values found before water abstraction were reestablished. We concluded that the dam did induce changes in the composition of benthic comunities, especially in the dry period. However, overall, the fauna seemed to be able to persist during periods when the flow was absent. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biomechanical, histological, and ultrastructural analyses of laser micro‐ and nano‐structured titanium alloy implants: A study in rabbit
Authors: Palmquist Anders , Lindberg Fredrik , Emanuelsson Lena , Brånemark Rickard , Engqvist Håkan , Thomsen Peter
Published: May 2009

The aim of this study was to evaluate the biomechanical properties and ultrastructure of the bone response of partly laser‐modified Ti6Al4V implants compared with turned, machined implants after 8 weeks in rabbit. The surface analyses performed with interference microscopy and electron microscopy showed increased surface topography with micro‐ and nano‐sized surface features as well as increased oxide thickness of the modified surface. The biomechanical testing demonstrated a 270% increase in torque value for the surface modified implants compared with the control implants. Histological evaluation of ground sections of specimens subjected to biomechanical testing revealed ongoing bone formation and remodeling. A histological feature exclusively observed at the laser‐modified surface was the presence of fracture in the mineralized bone rather than at the interface between the bone and implant. Transmission electron microscopy (TEM) was performed on Focused Ion Beam (FIB) prepared samples of the intact bone‐implant interface, demonstrating a direct contact between nanocrystalline hydroxyapatite and the oxide of the laser‐modified implant surface. In conclusion, laser‐modified titanium alloy implants have significantly stronger bone anchorage compared with machined implants and show no adverse tissue reactions. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Targeted molecular imaging of VEGF receptors overexpressed in ischemic microvasculature using chitosan‐DC101 conjugates
Authors: Lee Chang‐Moon , Kim Eun‐Mi , Cheong Su‐Jin , Kim Dong‐Wook , Lim Seok Tae , Sohn Myung‐Hee , Jeong Hwan‐Jeong
Published: May 2009

Expression of vascular endothelial growth factor receptors (VEGFRs) increases in ischemic muscles, and thus, VEGFR could potentially be used as marker to detect ischemia. Here, we investigated whether 99mTc or Cy5.5‐labeled chitosan‐DC101 conjugates could identify VEGFR‐2 overexpressed in ischemia. To this end, chitosan was conjugated with the DC101 antibody and Cy5.5, FITC, or the HYNIC chelator for 99mTc‐labeling. Targeting of the conjugate was evaluated in vitro and in vivo through cell‐binding studies and gamma/optical imaging, respectively. A hindlimb ischemic mouse model was surgically created by femoral artery occlusion. The chitosan‐DC101 conjugates exhibited VEGFR‐selective cell binding properties as determined by both confocal microscopy and flow cytometry. At postoperative times of 2, 12, and 24 h, 99mTc or Cy5.5‐labeled chitosan‐DC101 conjugates were intravenously injected into the mice, and gamma/optical imaging studies were conducted at 1 or 3 h. Both the gamma and optical imaging results indicated a significantly higher uptake in ischemic muscles when compared with the contralateral nonischemic muscle. Further, semiquantitative analysis of scintigraphic imaging data revealed that the ischemic to contralateral limb ratio was 4.5 ± 0.25 at 24 h postoperation. Western blotting analysis confirmed VEGFR expression in the ischemic muscle. In conclusion, we believe that 99mTc or Cy5.5‐labeled chitosan‐DC101 conjugates have the potential to be useful as VEGFR‐2‐targeted imaging agents for monitoring ischemia. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Bacterial plaque retention on oral hard materials: Effect of surface roughness, surface composition, and physisorbed polycarboxylate
Authors: McConnell Marla D. , Liu Yu , Nowak Andrew P. , Pilch Shira , Masters James G. , Composto Russell J.
Published: May 2009

Bacterial adhesion to oral hard materials is dependent on various factors, for example, surface roughness and surface composition. In this study, bacteria retention on three oral hard substrates, hydroxyapatite (HAP), enamel, and polished enamel (p‐enamel) were investigated. The surface morphology and roughness of the three substrates were measured by scanning probe microscopy. HAP had the roughest surface, followed by enamel and polished enamel. For each individual substrate type, the roughness was shown to increase with scan size up to 50 μm × 50 μm. For HAP and enamel, roughness decreased considerably after formation of a pellicle, while addition of polymer coating to the pellicle layer reduced roughness much less in comparison. Bacterial surface coverage was measured at 30 min, 3 h, and 24 h on both native and surface‐modified substrates, which were coated with two different polycarboxylate‐based polymers, Gantrez S97 and Carbopol 940. As a result, the polymer coated surfaces had reduced bacteria coverage compared with the native surfaces over all time points and substrates measured. The reduction is the combined effect of electrostatic repulsion and sequestering of Ca2+ ions at the surface, which plays a key role in the initial adhesion of bacteria to enamel surfaces in models of plaque formation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Titanium particles modulate expression of Toll‐like receptor proteins
Authors: Pajarinen Jukka , Mackiewicz Zygmunt , Pöllänen Raimo , Takagi Michiaki , Epstein Noah J. , Ma Ting , Goodman Stuart B. , Konttinen Yrjö T.
Published: May 2009

The role of Toll‐like receptors (TLRs) responding to microbial remnants, indolent biofilms or cellular byproducts in aseptic loosening of joint replacements is unknown. Thus, the effect of titanium (Ti) particles on TLR protein levels was evaluated. To create a model of particle‐induced inflammation, an intramedullary stainless steel rod with and without Ti particles was bilaterally placed in the femora of 14 mice. The animals were sacrificed at 2 or 10 weeks postoperatively and paraffin‐embedded femur sections were evaluated for TLR1, 2, 4, 5, 8, and 9 proteins using immunohistochemistry. Decrease in the number of TLR immunoreactive cells was observed between weeks 2 and 10 in both settings. Furthermore, in the presence of Ti particles, the numbers of TLR immunoreactive cells were lower than in the presence of rod only at both time points, suggesting downregulation of TLR expression by Ti‐particles per se. Accordingly, in a short‐term 24 h stimulation, downregulation of TLR4 mRNA (p < 0.02) was observed in vitro in RAW 264.7 cells challenged with Ti particles. Results suggest that after an initial inflammatory stage, TLRs are downregulated in response to Ti particles, possibly to inhibit excessive inflammation, although TLR downregulation might at the same time render tissues more susceptible to pathogens. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Parentage and relatedness in captive and natural populations of the Roseate Spoonbill (Aves: Ciconiiformes) based on microsatellite data
Authors: Miño Carolina Isabel , Sawyer Gregory Martin , Benjamin Robert Curliss , Del Lama Silvia Nassif
Published: May 2009

This study constitutes a first approach to evaluate the use of genetic information and relatedness estimators in the investigation of questions related to mating system and parentage in ex situ and in situ populations of the Roseate Spoonbill. We assessed the parentage assignments in 17 supposed families from US captive populations and investigated the genetic relationships among 67 nestlings sampled within 28 nests in Brazilian natural breeding colonies. Estimations of genetic relatedness values, hypothesis testing methods, simulations and maximum likelihood approaches were performed on data from four microsatellite loci. Parentage was confirmed in 61.5% of the registered parent–offspring relationships at zoo parks. Inconsistencies in assignments were investigated and the likely parents were identified for most of the hatchlings. Matings among relatives, not previously noticed based on behavioral observations, were identified by the use of genetic analyses. In natural populations, 33% of the sampled dyads were confidently classified as full‐sibs. Above 25% of the analyzed dyads were unrelated, indicating that more than one parent‐pair may have been responsible for the progeny. Our results demonstrate that genetic information can augment the precision in parentage assignment in captive Roseate Spoonbill populations, and this approach can contribute to their management and conservation. Results obtained using three different methodologies are concordant and point to the existence of a mating system other than monogamy for this species in the wild. The approaches implemented in this study can be applied to other waterbird species in which capture of adults is difficult. J. Exp. Zool. 311A:453–464, 2009. © 2009 Wiley‐Liss, Inc.
Seasonal pelage changes are synchronized by simulated natural photoperiods in Siberian hamsters (Phodopus sungorus)
Authors: Butler Matthew P. , Zucker Irving
Published: May 2009

The extent to which changing day lengths (DLs) synchronize the seasonal molt was assessed in nine cohorts of male and female Siberian hamsters (Phodopus sungorus) born into a simulated natural photoperiod (SNP) beginning 4 weeks before and ending 12 weeks after the summer solstice. Hamsters in early cohorts displayed rapid somatic and gonadal growth and early puberty, whereas those in later cohorts delayed puberty until the next spring. Despite the varying birth dates and puberty strategies, the seasonal pattern of change in pelage is much better predicted by calendar date than by age in both sexes. Males born over the course of 16 weeks first made the transition to the winter pelage during a 5‐week interval beginning on October 25; the autumn molt, however, was not significantly synchronized by either age or calendar date. The autumn molt of females on the other hand began 2 weeks later, and was significantly synchronized to calendar date with no detectable age effects. In both sexes, the autumn molt lagged gonadal and somatic seasonal changes by many weeks. Date of birth did not affect the timing of the spring molt, which was significantly synchronized by calendar date in both sexes. Incrementally changing photoperiods exert a strong organizing effect on the seasonal molt by providing hamsters with timing cues that are absent in laboratory analyses that employ static DLs and abrupt transitions from summer to winter DLs, thereby extending and validating conclusions derived from previous analyses. J. Exp. Zool. 311A:475–382, 2009. © 2009 Wiley‐Liss, Inc.
Deletion of BMP7 affects the development of bones, teeth, and other ectodermal appendages of the orofacial complex
Authors: Zouvelou Vasiliki , Luder Hans‐Ulrich , Mitsiadis Thimios A. , Graf Daniel
Published: May 2009

Sequential and reciprocal epithelial–mesenchymal interactions govern the development of most tissues and organs of the craniofacial region. Bone morphogenetic proteins (BMPs) are members of the transforming growth factor‐β family of secreted signaling molecules that have long been implied to have a significant contribution in this process. However, evidence for such a role during craniofacial development is largely missing. Using a lacZ reporter mouse we mapped the spatiotemporal expression of BMP7 in the developing craniofacial region. The observed pattern suggested a potential involvement of BMP7 in epithelial–mesenchymal interactions and thus a direct role for this molecule in the development of ectodermal appendages (teeth, hair follicle, lachrymal and sweat glands, taste buds) and, furthermore, palatal formation. To correlate the expression to function we analyzed germline deleted conditional BMP7‐deficient embryos for malformations. We found developmental defects in many craniofacial structures such as teeth, eyes, whiskers, hair follicles, salivary glands, and palate. These findings place BMP7 as a central mediator of epithelial–mesenchymal interactions that are necessary for the correct development of structures belonging to the orofacial complex. J. Exp. Zool. (Mol. Dev. Evol.) 312B:361–374, 2009. © 2009 Wiley‐Liss, Inc.
Synthesis and antitumor activity of novel pyrazolylenaminone and bis(pyrazolyl)ketones via hydrazonoyl halides
Authors: Shawali Ahmad S. , Sherif Sherif M. , El‐Merzabani Mahmoud M. , Darwish Manal A. A.
Published: May 2009

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3‐Acetyl‐4‐benzoyl‐1,5‐diphenylpyrazole reacts with DMF‐DMA to give the novel enaminone 2. The reaction of the latter with various hydrazonoyl halides afforded regioselectively the respective substituted (3‐pyrazolyl)(4‐pyrazolyl)ketones 4 in good over all yield. The preliminary screening for the antitumor activity of the synthesized compounds 2 and 4a, 4b, 4c, 4d, 4e, 4f, 4g against human breast cancer cell line (MCF‐7) revealed that both compounds 2 and 4b have high‐antitumor activity. SAR is discussed. J. Heterocyclic Chem., 46, 548 (2009).
Synthesis and reactivity of spiro[1,3,4‐thiadiazoline‐2,4′‐thioflavans] and analogues
Authors: Somogyi László
Published: May 2009

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Racemic thioflavanone (thio)acylhydrazones undergo transformation into racemic 3‐acetylspiro[1,3,4‐oxa(thia)‐diazoline‐2,4′‐thioflavans] with trans O(1) or S(1) and Ph(2′eq) under acetylating conditions. Conjugation between the ethylenic bond and sp2 C(4) in thioflavones encumber both the formation of (thio)acylhydrazones and their subsequent spirocyclization. On the other hand, subsequent dehydrogenation of the thiopyran moiety of spiro compounds results in formation of sp2 C(4) and simultaneous degradation of the spirodiazoline ring. J. Heterocyclic Chem., 46, 399 (2009).
Reaction of 4,5‐dichloro‐2‐chloromethylpyridazin‐3(2H)‐one with phenols
Authors: Kang Seung‐Beom , Park Song‐Eun , Lee Hyung‐Geun , Kim Bo Ram , Jung Kwang‐Ju , Won Ju‐Eun , Kim Min‐Jung , Yoon Yong‐Jin
Published: May 2009

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The regiochemistry was investigated for the reaction of 2‐chloromethyl‐4,5‐dichloropyridazin‐3(2H)‐one (1) with some phenols 2 in the presence of a base in organic solvents. Seven diphenoxy derivatives 5 were synthesized selectively from 1 and phenols 2 under two optimized conditions. The product distributions of these reactions are dependent on the base, the solvent, and/or the substitutes of phenols. J. Heterocyclic Chem., (2009).
Multiecho time‐resolved acquisition (META): A high spatiotemporal resolution dixon imaging sequence for dynamic contrast‐enhanced MRI
Authors: Saranathan Manojkumar , Rettmann Dan , Bayram Ersin , Lee Christine , Glockner James
Published: May 2009

Purpose

To evaluate a new dynamic contrast‐enhanced (DCE) imaging technique called multiecho time‐resolved acquisition (META) for abdominal/pelvic imaging. META combines an elliptical centric time‐resolved three‐dimensional (3D) spoiled gradient‐recalled echo (SPGR) imaging scheme with a Dixon‐based fat‐water separation algorithm to generate high spatiotemporal resolution volumes.

Materials and Methods

Twenty‐three patients referred for hepatic metastases or renal masses were imaged using the new META sequence and a conventional fat‐suppressed 3D SPGR sequence on a 3T scanner. In 12 patients, equilibrium‐phase 3D SPGR images acquired immediately after META were used for comparing the degree and homogeneity of fat suppression, artifacts, and overall image quality. In the remaining 11 of 23 patients, DCE 3D SPGR images acquired in a previous or subsequent examination were used for comparing the efficiency of arterial phase capture in addition to the qualitative analysis for the degree and homogeneity of fat suppression, artifacts, and overall image quality.

Results

META images were determined to be significantly better than conventional 3D SPGR images for degree and uniformity of fat suppression and ability to visualize the arterial phase. There were no significant differences in artifact levels or overall image quality.

Conclusion

META is a promising high spatiotemporal resolution imaging sequence for capturing the fast dynamics of hyperenhancing hepatic lesions and provides robust fat suppression even at 3T. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.
Study of the characteristic fragmentation behavior of hydroquinone glycosides by electrospray ionization tandem mass spectrometry with optimization of collision energy
Authors: Liu Ying , He Jiuming , Zhang Ruiping , Shi Jiangong , Abliz Zeper
Published: May 2009

The fragmentation behavior of hydroquinone glycosides involving one or two sugar groups fromFraxinus sieboldianaand their analogue arbutin was investigated systematically by electrospray ionization tandem mass spectrometry in negative ion mode. The characteristic fragmentation reaction of these compounds was through the homolytic and heterolytic cleavage of theO‐glycosidic bond to produce radical aglycone ion ([Y0− H]−•) and aglycone ion (Y0−), respectively. Unambiguous differentiation between the mono‐O‐glycoside isomers which differ in glycosylation position was achieved by comparing the relative abundance of [Y0− H]−•and Y0−ions with the optimized collision energy. In the fragmentation of 1, 4‐di‐O‐glycosides, only the Y0−ion was produced when the first glucosyl residue was expelled. However, both the [Y0− H]−•and Y0−ions were present when the second glucosyl residue was eliminated. In addition, an interesting [Y0‐2H]−ion was present in the product ion spectra of hydroquinone glycosides with methoxy group(s) substituted at C‐3 or/and C‐5 positions of the benzene ring. The results of this study can facilitate the rapid determination of hydroquinone glycosides in crude plant extracts and also reveal that the systematic investigation and optimization of collision energy play an important role in the differentiation of isomers which have subtle differences in structures. Copyright © 2009 John Wiley & Sons, Ltd.
Snow in the McMurdo Dry Valleys, Antarctica
Authors: Fountain Andrew G. , Nylen Thomas H. , Monaghan Andrew , Basagic Hassan J. , Bromwich David
Published: May 2009

Snowfall was measured at 11 sites in the McMurdo Dry Valleys to determine its magnitude, its temporal changes, and spatial patterns. Annual values ranged from 3 to 50 mm water equivalent with the highest values nearest the coast and decreasing inland. A particularly strong spatial gradient exists in Taylor Valley, probably resulting from local uplift conditions at the coastal margin and valley topography that limits migration inland. More snow occurs in winter near the coast, whereas inland no seasonal pattern is discernable. This may be due, again, to local uplift conditions, which are common in winter. We find no influence of the distance to the sea ice edge. Katabatic winds play an important role in transporting snow to the valley bottoms and essentially double the precipitation. That much of the snow accumulation sublimates prior to making a hydrologic contribution underscores the notion that the McMurdo Dry Valleys are indeed an extreme polar desert. Copyright © 2009 Royal Meteorological Society
Differential response of short‐ and long‐duration cassava cultivars to applied mineral nitrogen
Authors: Byju G. , Haripriya Anand M.
Published: May 2009

The differential response of two contrasting cassava cultivars to different rates of soil‐applied nitrogen (N) on the number of tuberous roots, harvest index, yield, nitrogen uptake, and fertilizer‐nitrogen‐use efficiency was studied over a period of 2 years on a typic Plinthustults in Kerala state in Southern India. The experiment was laid out in a split‐plot design with two popular cultivars of cassava, namely Sree Vijaya (6 months) and M‐4 (10 months) in the main plots, and eight urea‐N rates (0, 12.5, 25, 50, 75, 100, 150, and 200 kg ha–1) in subplots. Half of the N was applied at the time of planting and the other half 60 d later. The study revealed significant differences between the two cultivars regarding their response to fertilizer‐N application. The tuberous‐root yield of the short‐duration cultivar Sree Vijaya increased significantly up to 100 kg N ha–1 whereas the yield of the long‐duration cultivar M‐4 increased significantly only up to 50 kg N ha–1 rate. Also the N‐use‐efficiency parameters (i.e., agronomic, recovery, and physiological efficiencies) were higher in Sree Vijaya than in M‐4 but declined at N rates beyond 100 kg ha–1. The more efficient N use in the short‐duration cultivar was associated with a higher N uptake and a more efficient internal use.
Comparison of extraction techniques and modeling of accelerated solvent extraction for the authentication of natural vanilla flavors
Authors: Cicchetti Esmeralda , Chaintreau Alain
Published: May 2009

Accelerated solvent extraction (ASE) of vanilla beans has been optimized using ethanol as a solvent. A theoretical model is proposed to account for this multistep extraction. This allows the determination, for the first time, of the total amount of analytes initially present in the beans and thus the calculation of recoveries using ASE or any other extraction technique. As a result, ASE and Soxhlet extractions have been determined to be efficient methods, whereas recoveries are modest for maceration techniques and depend on the solvent used. Because industrial extracts are obtained by many different procedures, including maceration in various solvents, authenticating vanilla extracts using quantitative ratios between the amounts of vanilla flavor constituents appears to be unreliable. When authentication techniques based on isotopic ratios are used, ASE is a valid sample preparation technique because it does not induce isotopic fractionation.
Potential of combining of liquid membranes and molecularly imprinted polymers in extraction of 17β‐estradiol from aqueous samples
Authors: Nemulenzi Olga , Mhaka Byron , Cukrowska Ewa , Ramström Olof , Tutu Hlanganani , Chimuka Luke
Published: May 2009

The potential of combination of liquid membranes (microporous membrane liquid–liquid extraction) and molecularly imprinted polymers (MIPs) was performed using 17β‐estradiol (E2) as model compound. The model compound was extracted from aqueous sample through a hydrophobic porous membrane that was impregnated with hexane/ethyl acetate (3:2), which also formed part of the acceptor phase. In the acceptor phase, the compound was bound onto MIP particles that were also part of the organic phase. The potential of such combination was optimised for the type and amount of MIP particles in the organic acceptor phase, the extraction time, and the type of organic acceptor solvent. Ultrasound assisted binding of E2 onto MIP particles was also investigated. MIPs prepared by precipitation polymerization were found to be superior to those prepared by bulk polymerization. Increase in the extraction time and the amount of MIP particles in the acceptor phase led to more E2 binding onto the MIP particles. Hexane/ethyl acetate (3:2) as an organic acceptor was found to give higher E2 binding onto MIP particles compared to toluene, diethyl ether, and hexane. Ultrasound was furthermore found to increase the binding of E2 onto MIP particles. The selectivity of the technique was demonstrated by extracting wastewater and where clean chromatograms were obtained compared to liquid membrane extractions (SLMs) alone.
Development and validation of an LC method for the determination of emtricitabine and related compounds in the drug substance
Authors: Ashenafi Dunge , Verbeek Ann , Hoogmartens Jos , Adams Erwin
Published: May 2009

A robust, precise, sensitive, linear, and simple RP LC method coupled with UV for the determination of emtricitabine or 2′,3′‐dideoxy‐5‐fluoro‐3′‐thiacytidine (FTC) and its related substances is described. The method uses an RP C18 column (25 cm×4.6 mm i.d.), 5 μm kept at a temperature of 35°C. The mobile phases for gradient elution consist of ACN, phosphate buffer (pH 4.4), and water. The flow rate is 1.0 mL/min and UV detection is performed at 280 nm. A system suitability test (SST) was developed to verify the adequate performance of the chromatographic system. The developed method was further validated with respect to robustness, precision, sensitivity, and linearity. A central composite design was applied to examine the robustness of the method. The method shows good precision, sensitivity, linearity, and robustness. Three commercial FTC samples were examined using this method. This method is suitable to be used for the determination of related substances and assay of FTC.
Quantitative structure migration relationship modeling of migration factor for some benzene derivatives in micellar electrokinetic chromatography
Authors: Fatemi Mohammad Hossein , Shamseddin Hoda , Malekzadeh Hanieh
Published: May 2009

Multiple linear regression (MLR) and artificial neural network (ANN) were used to predict the migration factors of benzene derivatives in MEKC. Some topological and electronic descriptors were calculated for each solute in the data set, and then the stepwise MLR method was used to select more significant descriptors and MLR model development. The selected descriptors are: Kier & Hall index (order1), relative negative charge surface area, HA dependent HDSA‐2/TMSA, C component of moment of inertia, Y component of dipole moment and SDS to decanol ratio in mobile phase. In the next step these descriptors were used as input of an ANN. After optimization and training of ANN it was used to predict the migration factors of external test set as well as internal and training sets. The root mean square errors for ANN predicted migration factors of training, internal and external test set were 0.110, 0.231 and 0.228, respectively, while these values are 0.200, 0.240 and 0.247 for the MLR model, respectively. Comparison between these values and other statistical parameters for these two models revealed that there were not any significant differences between ANN and MLR in prediction of solute migration factors in MEKC.
Separation of natural product using columns packed with Fused‐Core particles
Authors: Yang Peilin , Litwinski George R. , Pursch Matthias , McCabe Terry , Kuppannan Krishna
Published: May 2009

Three HPLC columns packed with 3 μm, sub‐2 μm, and 2.7 μm Fused‐Core (superficially porous) particles were compared in separation performance using two natural product mixtures containing 15 structurally related components. The Ascentis ExpressTM C18 column packed with Fused‐Core particles showed an 18% increase in column efficiency (theoretical plates), a 76% increase in plate number per meter, a 65% enhancement in separation speed and a 19% increase in back pressure compared to the Atlantis T3TM C18 column packed with 3 μm particles. Column lot‐to‐lot variability for critical pairs in the natural product mixture was observed with both columns, with the Atlantis T3 column exhibiting a higher degree of variability. The Ascentis Express column was also compared with the AcquityTM BEH column packed with sub‐2 μm particles. Although the peak efficiencies obtained by the Ascentis Express column were only about 74% of those obtained by the Acquity BEH column, the 50% lower back pressure and comparable separation speed allowed high‐efficiency and high‐speed separation to be performed using conventional HPLC instrumentation.
Direct UV detection of underivatized amino acids using capillary electrophoresis with online sweeping enrichment
Authors: Jiang Xuemei , Xia Zhining , Wei Weili , Gou Qian
Published: May 2009

This is an original report proposed a CE method for direct analysis of the underivatized amino acids using UV detection with relatively higher sensitivity, which was based on coordination interactions between amino acids and Cu (II) ions. In addition, an online sweeping preconcentration technique was easily combined to improve the detection sensitivity. Satisfying separations of the amino acids were obtained under optimized conditions: 50 mmol/L CuSO4–0.05% HAc–H2O (pH 4.5), and the separation voltage of 15 kV. The LODs for the analytes ranged from 0.1 to 0.5 μmol/L. The linearity of detection for all analytes was two orders of magnitude with the correlation coefficients greater than 0.99. The repeatability was displayed with an RSD less than 3% for migration time and peak height (n = 5). Moreover, some amino acids in real samples of human saliva and green tea were analyzed by this direct UV detection CE method with acceptable sensitivity.
Method for routine screening of pesticides and metabolites in meat based baby‐food using extraction and gas chromatography‐mass spectrometry
Authors: Przybylski Cédric , Segard Christophe
Published: May 2009

A simple and complete multiresidue method has been developed for the routine determination of 236 pesticides and degradation products, in meat based baby‐food. This original approach combines a modified Quick Easy Cheap Effective Rugged and Safe (QuEChERS) sample preparation method using a triple partitioning extraction step with water/ACN/hexane and a system composed of GC with programmable temperature vaporization injector hyphenated to an IT‐MS. Detection was performed in full scan mode, with one quantification ion and one identification ion. We firstly report here the hexane addition in the extraction step to eliminate a major part of lipophile co‐extracts. Direct consequences were the increasing of method sensitivity and the diminishment of the frequency of maintenance of the analytical instrument. The recovery data were obtained by spiking blank samples at three concentration levels (10, 50 and 200 μg/kg) over five replicates, yielding average recoveries in the range 70–121% with a RSD evaluated between 2–15%. Linearity was fixed in the range of 10–300 μg/kg with determination coefficients (R2) superior or equal to 0.9814 for all target analytes. Best LODs and LOQs were established as 0.03 and 0.1 μg/kg, respectively. Total instrumental analysis of all molecules was carried out in less than 1 h.
Sampling and analysis of nanoparticles with cold fibre SPME device
Authors: Koziel Jacek A. , Hosseinzadeh Haddadi Shokouh , Koch Wolfgang , Pawliszyn Janusz
Published: May 2009

A new approach is described to capture nano‐size aerosols on internally‐cooled micro tubing of the solid‐phase microextraction (SPME) device followed by convenient introduction of the collected analytes into analytical instrument. Particles were generated using an aerosol formation by homogeneous nucleation of an organic vapor, and subsequent growth to nano‐size particles by coagulation of decanedioic acid, bis[2‐ethylhexyl] ester (DEHS). The approach was validated by using carbon dioxide‐cooled micro tubing to collect the nanosize DEHS particles followed by analyses on GC‐flame ionization detector (FID). Particle size ranged from 150 to 590 nm. Temperature difference between the SPME device and DEHS particles mixture created a temperature gradient and resulted in thermophoretic effect that was determining the extraction rate. SPME device was cooled to as low as –75°C, while the DEHS remained close to room temperature. Several aspects of nanoparticle sampling were tested to demonstrate the principle of the sampling approach. These included the effects of thermal gradient, sample flow rate, sampling time, CO2 delivery mode (constant coolant delivery vs. constant temperature), and particle size. Results were normalized to measure particulate concentrations using direct sampling with PTFE filters. Nanoparticle extractions of DEHS mass were proportional to sampling time. Normalized mass of DEHS extracted increased with increase in temperature gradient and with increase of the cross flow velocity. Preliminary results indicate that the variation of heat transfer boundary layer caused by the variation in the cross flow velocity produce self‐compensating effect at constant coolant delivery, indicating that this approach could be used for field determinations including the time‐weighted average sampling of nanoparticles. Thus, it may be possible to develop simple device based on this concept for field applications.
Characterization of volatile substances in apples from Rosaceae family by headspace solid‐phase microextraction followed by GC‐qMS
Authors: Ferreira Liseth , Perestrelo Rosa , Caldeira Michael , Câmara José S.
Published: May 2009

The volatile composition of different apple varieties of Malus domestica Borkh. species from different geographic regions at Madeira Islands, namely Ponta do Pargo (PP), Porto Santo (PS), and Santo da Serra (SS) was established by headspace solid‐phase microextraction (HS‐SPME) procedure followed by GC‐MS (GC‐qMS) analysis. Significant parameters affecting sorption process such as fiber coating, extraction temperature, extraction time, sample amount, dilution factor, ionic strength, and desorption time, were optimized and discussed. The SPME fiber coated with 50/30 μm divinylbenzene/carboxen/PDMS (DVB/CAR/PDMS) afforded highest extraction efficiency of volatile compounds, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 50°C for 30 min with constant magnetic stirring. A qualitative and semi‐quantitative analysis between the investigated apple species has been established. It was possible to identify about 100 of volatile compounds among pulp (46, 45, and 39), peel (64, 60, and 64), and entire fruit (65, 43, and 50) in PP, PS, and SS apples, respectively. Ethyl esters, terpenes, and higher alcohols were found to be the most representative volatiles. α‐Farnesene, hexan‐1‐ol and hexyl 2‐methylbutyrate were the compounds found in the volatile profile of studied apples with the largest GC area, representing, on average, 24.71, 14.06, and 10.80% of the total volatile fraction from PP, PS, and SS apples. In PP entire apple, the most abundant compounds identified were α‐farnesene (30.49%), the unknown compound m/z (69, 101, 157) (21.82%) and hexyl acetate (6.57%). Regarding PS entire apple the major compounds were α‐farnesene (16.87%), estragole (15.43%), hexan‐1‐ol (10.94), and E‐2‐hexenal (10.67). α‐Farnesene (30.3%), hexan‐1‐ol (18.90%), 2‐methylbutanoic acid (4.7%), and pentan‐1‐ol (4.6%) were also found as SS entire apple volatiles present in a higher relative content. Principal component analysis (PCA) of the results clustered the apples into three groups according to geographic origin. Linear discriminant analysis (LDA) was performed in order to detect the volatile compounds able to differentiate the three kinds of apples investigated. The most important contributions to the differentiation of the PP, PS, and SS apples were ethyl hexanoate, hexyl 2‐methylbutyrate, E,E‐2,4‐heptadienal, p‐ethyl styrene, and E‐2‐hexenal.
Full separation of oligomers in block copolymers of ethylene oxide and propylene oxide
Authors: Malik Muhammad Imran , Trathnigg Bernd
Published: May 2009

In this study di‐ and triblock copolymers of ethylene oxide (EO) and propylene oxide (PO) are analyzed by using CAP for one block and adsorption for the other block. This gives a complete picture of EO‐ and PO‐based block copolymer with respect to the oligomers of both blocks. A full resolution of the individual oligomers can be achieved for both blocks up to an average molecular weight of 1000–1500 of each block.
Teaching program for the Unified Dyskinesia Rating Scale
Authors: Goetz Christopher G. , Nutt John G. , Stebbins Glenn T. , Chmura Teresa A.
Published: May 2009

The Unified Dyskinesia Rating Scale (UDysRS) has been introduced as a comprehensive rating tool for the evaluation of dyskinesias in Parkinson's disease (PD). To enhance a uniform application, we developed a DVD‐based training program with instructions, patient examples, and a certification exercise. For training on the objective assessment of dyskinesia, seventy PD patients spanning the gamut of dyskinesias (none to severe) were videotaped during four tasks of daily living (speaking, drinking from a cup, putting on a coat, and walking). Dyskinesia severity in seven body parts was rated by 20 international movement disorder specialists using the UDysRS for impairment. Each task was also rated for disability. Inter‐rater reliability was assessed with generalized weighted kappa and intraclass correlation coefficients. For the teaching program, examples of each severity level and each body part were selected based on the criterion that they received a uniform rating (± 1 point) by at least 75% of the raters. For the certification exercise, four cases were selected to represent the four quartiles of overall objective UDysRS scores to reflect slight, mild, moderate, and severe dyskinesia. Each selection was based on the highest inter‐rater reliability score for that quartile (minimum kappa or intraclass correlation coefficient = 0.6). UDysRS ranges for certification were calculated based on the 95% confidence interval. The teaching program lasts 41 min, and the certification exercise requires 10 min (total 51 min). This training program, based on visual examples of dyskinesia and anchored in scores generated by movement disorder experts is aimed at increasing homogeneity of ratings among and within raters and centers. Large‐scale multicenter randomized clinical trials of dyskinesia treatment are strengthened by a uniform standard of scale application. © 2009 Movement Disorder Society
Homocysteine levels after acute levodopa intake in patients with Parkinson's disease
Authors: Müller Thomas , Kuhn Wilfried
Published: May 2009

Levodopa (L‐dopa) administered with a dopadecarboxylase inhibitor (DDI) increases homocysteine plasma levels. This may support the onset of atherosclerosis‐related disorders and neuropsychiatric complications in patients with Parkinson's disease (PD). This homocysteine elevation is considered as long‐term effect of chronic L‐dopa/DDI treatment. Little is known about the acute effects of L‐dopa/DDI intake on homocysteine generation. The objective of this trial was to investigate the relations between L‐dopa and homocysteine after acute L‐dopa/DDI administration in PD patients with different L‐dopa metabolism. Thirty PD patients were divided into groups with superior (I) and less (II) L‐dopa absorption after standardized intake of 125 mg L‐dopa/benserazide with determination of L‐dopa, 3‐O‐methyl‐dopa (3‐OMD) and homocysteine in plasma at baseline, 30, 60, and 90 minutes. There was a homocysteine increase in Group I (F = 5; P = 0.005) and a moderate decrease in Group II (F = 4.27; P = 0.01). A rise of 3‐OMD (F = 10.51; P < 0.0001) appeared in Group I, but not in Group II (F = 0.91; P = 0.44), accordingly L‐dopa accumulation was better in Group I than in Group II. Thus, in conclusion, L‐dopa metabolism is an important component for homocysteine elevation after one time L‐dopa/DDI administration in PD patients. © 2009 Movement Disorder Society