bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Tyrosine Phosphatase 2(256–760) Construct as a New, Sensitive Marker for the Detection of Islet Autoimmunity in Type 2 Diabetic Patients
Authors: Tiberti Claudio , Giordano Carla , Locatelli Mattia , Bosi Emanuele , Bottazzo Gian Franco , Buzzetti Raffaella , Cucinotta Domenico , Galluzzo Aldo , Falorni Alberto , Dotta Francesco
Published: March 2008

OBJECTIVE—The presence of autoantibodies to islet antigens GAD and/or tyrosine phosphatase 2 (IA-2) in type 2 diabetic patients (latent autoimmune diabetes in adults [LADA]) identifies subjects at high risk to develop insulin dependency. The aim of this study was to dissect humoral anti–IA-2 immune response in Caucasian LADA patients, identifying the most sensitive construct to evaluate IA-2 immunoreactivity and comparing LADA IA-2 epitope specificities to those found in type 1 diabetes.

RESEARCH DESIGN AND METHODS—We analyzed 177 LADA and 978 type 2 diabetic patients with different disease duration, collected in a nationwide Italian survey, the Non–Insulin Requiring Autoimmune Diabetes (NIRAD) study aimed at assessing prevalence and characteristics of autoimmune diabetes in type 2 diabetic patients and 106 newly diagnosed type 1 diabetic patients (53 children, 53 adults). By radioimmunoassay, we analyzed humoral immunoreactivity to seven IA-2 constructs: IA-2PTP (687–979), IA-2(761–964), IA-2(256–760), IA-2JM (601–630), IA-2IC (605–979), IA-2BDC (256–556:630–979), and IA-2FL (1–979).

RESULTS—IA-2(256–760) fragment was identified as the marker with the highest sensitivity for detection of humoral IA-2 immunoreactivity in LADA patients, identifying IA-2 autoantibodies in ∼30% of GAD antibody (GADA)-positive LADA patients and in 3.4% of GADA-negative type 2 diabetic patients. LADA IA-2(256–760)A positivity was associated with an increased frequency of autoimmune diabetes HLA-susceptible genotypes and with a higher risk for developing thyroid autoimmunity compared with autoantibody-negative type 2 diabetic patients. At disease diagnosis, adult-onset type 1 diabetic and LADA patients showed a lower IA-2 COOH-terminal immunoreactivity compared with childhood-onset type 1 diabetic patients.

CONCLUSIONS—IA-2 immunoreactivity in LADA patients has thus far been underestimated, and IA-2(256–760) autoantibody detection may represent a novel diagnostic tool for the identification of islet autoimmunity in these patients.
β-Cell Dysfunction in Subjects With Impaired Glucose Tolerance and Early Type 2 Diabetes
Authors: Festa Andreas , Williams Ken , Hanley Anthony J.G. , Haffner Steven M.
Published: March 2008

OBJECTIVE—Methods to assess β-cell function in clinical studies are limited. The aim of the current study was to compare a direct measure of insulin secretion with fasting surrogate markers in relation to glucose tolerance status.

RESEARCH DESIGN AND METHODS—In 1,380 individuals from the Insulin Resistance Atherosclerosis Study, β-cell function was assessed using a frequently sampled intravenous glucose tolerance test (first-phase insulin secretion; acute insulin response [AIR]), homeostasis model assessment of β-cell function (HOMA-B), proinsulin levels, and the proinsulin-to-insulin ratio. β-Cell function was cross-sectionally analyzed by glucose tolerance categories (normal glucose tolerance [NGT], n = 712; impaired glucose tolerance [IGT], n = 353; newly diagnosed diabetes by 2-h glucose from an oral glucose tolerance test [OGTT] [DM2h], n = 80; newly diagnosed diabetes by fasting glucose [DMf], n = 135; or newly diagnosed diabetes by fasting and 2-h glucose and established diabetes on diet/exercise only [DM], n = 100).

RESULTS—In Spearman correlation analyses, proinsulin and the proinsulin-to-insulin ratio were only modestly inversely related to AIR (r values from −0.02 to −0.27), and AIR was strongly related to HOMA-B (r values 0.56 and 0.58). HOMA-B markedly underestimated the magnitude of the β-cell defect across declining glucose tolerance, especially for IGT and new DM by OGTT compared with AIR. Analyses adjusting for insulin sensitivity showed that β-cell function was compromised in IGT, DM2h, DMf, and DM, relative to NGT, by 13, 12, 59, and 62% (HOMA-B) and by as much as 40, 60, 80, and 75%, using AIR.

CONCLUSIONS—Subjects with IGT and early-stage, asymptomatic type 2 diabetic patients have more pronounced β-cell defects than previously estimated from epidemiological studies using homeostasis model assessment.
Kinin B1 Receptor Deficiency Leads to Leptin Hypersensitivity and Resistance to Obesity
Authors: Mori Marcelo A. , Araújo Ronaldo C. , Reis Felipe C.G. , Sgai Daniela G. , Fonseca Raphael G. , Barros Carlos C. , Merino Vanessa F. , Passadore Mariana , Barbosa Ana M. , Ferrari Bernard , Carayon Pierre , Castro Charlles H.M. , Shimuta Suma I. , Luz Jacqueline , Bascands Jean-Loup , Schanstra Joost P. , Even Patrick C. , Oliveira Suzana M. , Bader Michael , Pesquero João B.
Published: March 2008

OBJECTIVE—Kinins mediate pathophysiological processes related to hypertension, pain, and inflammation through the activation of two G-protein–coupled receptors, named B1 and B2. Although these peptides have been related to glucose homeostasis, their effects on energy balance are still unknown.

RESEARCH DESIGN AND METHODS—Using genetic and pharmacological strategies to abrogate the kinin B1 receptor in different animal models of obesity, here we present evidence of a novel role for kinins in the regulation of satiety and adiposity.

RESULTS—Kinin B1 receptor deficiency in mice (B1−/−) resulted in less fat content, hypoleptinemia, increased leptin sensitivity, and robust protection against high-fat diet–induced weight gain. Under high-fat diet, B1−/− also exhibited reduced food intake, improved lipid oxidation, and increased energy expenditure. Surprisingly, B1 receptor deficiency was not able to decrease food intake and adiposity in obese mice lacking leptin (ob/ob-B1−/−). However, ob/ob-B1−/− mice were more responsive to the effects of exogenous leptin on body weight and food intake, suggesting that B1 receptors may be dependent on leptin to display their metabolic roles. Finally, inhibition of weight gain and food intake by B1 receptor ablation was pharmacologically confirmed by long-term administration of the kinin B1 receptor antagonist SSR240612 to mice under high-fat diet.

CONCLUSIONS—Our data suggest that kinin B1 receptors participate in the regulation of the energy balance via a mechanism that could involve the modulation of leptin sensitivity.
Microstructural changes at the ultra-precision machined surface of Zn–Al based alloy
Authors: To S. , Zhu Y. H. , Lee W. B.
Published: March 2008

Using X-ray diffraction and back-scattered electron microscopy techniques, microstructural changes and phase decomposition at the ultra-precision machined surface of a Zn – Al based alloy were studied. The effects of the depth of cut on the microstructural changes were discussed in relation to the creep deformation, and the milling-induced microstructural changes. Structural evolution of the chip from the machining was studied in order to understand the ultra-precision machining induced phase decomposition. The effect of ultra-precision machining on the hardness of the surface of the alloy specimen was studied.
Study of structural and electrical properties of arsenic ferrites
Authors: Zade Prashant D. , Vanerkar Atul P. , Dharmadhikari Dattatreya M.
Published: March 2008

The effect of inclusion of trivalent arsenic ions with increasing arsenic concentration on the structural, electrical and thermal properties of the system As
x
Fe3 – x
O4 (x = 0.2, 0.4, 0.6, 0.8 and 1.0), synthesized at ambient temperature have been studied. Thermal measurements from room temperature to 1173 K and DC resistivity measurements with activation energy calculations were used for this purpose. Thermal measurements were carried out on these value added products. This investigation provides evidence for all compounds of the system. In particular: 1) They are stable up to 473 K and further only a small loss in weight was observed for the temperature range of 473 K – 1113 K, 2) In As0.2Fe2.8O4, a strong exothermic peak was observed at around 561 K, which has been shifted to 541 K for AsFe2O4, this shows the phase transition and sample crystallization. X-ray diffraction was used for characterization and DC resistivity measurement from room temperature to 623 K shows semi conducting behavior. The present work reveals that the incorporation of As3+ ions in the lattice of magnetite results in orthorhombic symmetry for arsenic composition x = 0.2 to x = 1.0.
Flood pulsing and metacommunity dynamics in a desert riparian ecosystem
Authors: Boudell Jere A. , Stromberg Juliet C.
Published: March 2008

Questions:

1. Does flood pulsing drive metacommunity dynamics and provide insurance against catastrophic flooding in desert southwestern riparian ecosystems? 2. Do upland and wetland species in the floodplain differ in their dynamics?

Location:

Southwestern USA.

Methods:

We sampled vegetation and propagule banks in four communities along a floodplain hydrogradient. Plant species were classified as wetland or upland and community wetland indicator scores were calculated. ANOVA tested for differences between data categories amongst communities (extant vegetation and propagule banks) and soil depths. Sorensen's similarity coefficient was calculated to determine compositional similarity between vegetation and propagule banks.

Results:

Community propagule banks had high similarity indicating broad dispersal by flood waters. Wetland propagules were present in soils from channel bars to floodplain edges, despite declines in wetland vegetation with distance from channel. Wetland communities in propagule banks were dissimilar from those in vegetation except on channel bars. Upland species (vegetation and propagule banks) increased with distance from channel. Propagules of upland species were most abundant in the litter, and were compositionally similar to upland species in most communities.

Conclusions:

Flood pulsing is one mechanism that drives spatiotemporal metacommunity dynamics in dynamic desert riparian ecosystems. The homogenized regional propagule bank created by flood pulsing provides wetland species with a mechanism to escape local extinction by allowing for recoloni‐zation after flooding creates suitable establishment conditions. Upland species are able to germinate from in‐situ sources after small‐scale flooding or rainfall moistens soil. In fluctuating environments, these dynamics sustain biodiversity in the face of ongoing environmental change.
Interaction Scheme and Temperature Behavior of Energy Transfer in a Light‐Emitting Inorganic‐Organic Composite System
Authors: Neves Antonio Alvaro Ranha , Camposeo Andrea , Cingolani Roberto , Pisignano Dario
Published: March 2008

Determining and controlling the inter‐component excitation conversion in light‐emitting nanocomposite materials is a key factor for predicting the composite luminescence properties and for the operation of many opto‐electronic devices. Here we present an extensive study of the inter‐component energy transfer in the composite system given by ZnO particles interacting with the conjugated polymer, poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene]. The composite emission is studied upon varying the acceptor concentration, and the system temperature in the range 50–300 K. The temperature dependence of the energy transfer rate is described by a rate model, taking into account the temperature dependence of the single components nonradiative decay rates, and a dipole–surface interaction scheme in the hybrid material. The proposed model accounts very well for the experimental observation of energy transfer and can be used to predict the temperature behavior of the emission from light‐emitting nanocomposite materials.
Organization of Organic Molecules with Inorganic Nanoparticles: Hybrid Nanodiodes
Authors: Mohanta Kallol , Batabyal Sudip K. , Pal Amlan J.
Published: March 2008

A monolayer of inorganic nanoparticles and a monolayer of organic molecules have been electrostatically assembled in sequence. Such assemblies or organizations exhibit electrical rectification. When the sequence of the organization is reversed, the direction of rectification becomes opposite. In both n‐type ZnO/organic and organic/n‐ZnO assemblies, electron flow is favorable from the n‐ZnO nanoparticle to the (electron‐accepting) organic molecule. While the individual components do not show any rectification, substitutes of the organic molecule tune electrical rectification. Junctions between a p‐type ZnO nanoparticle and an electron‐donating metal phthalocyanine favor current flow in the nanoparticle‐to‐phthalocyanine direction. The rectification in a junction between a nanoparticle and an organic molecule is due to the parity between free carriers in the former component and the type of carrier‐accepting nature in the latter one. By observing electrical rectification with the tip of a scanning tunneling microscope, organic/inorganic hybrid nanodiodes or rectifiers on the molecular/nanoscale have been established.
Solvent free biocatalytic synthesis of vinyl monomers by lipase immobilized on hydrogels
Authors: Chauhan Ghanshyam S. , Kanwar Shamsher S. , Kumar Rajeev , Kumar Yogesh , Chauhan Sandeep
Published: March 2008

Simple novel research plan has been employed to tailor supports for lipase immobilization. N‐aminoethylacrylamide (N‐AEAAm) and N‐aminoethylmethacrylamide (N‐AEMAAm) were crosslinked with N,N‐methylene bisacrylamide (N,N‐MBAAm) and consequently reacted separately with acrylic acid (AAc) and methacrylic acid (MAAc). The hydrogels thus formed, consist of both amide and carboxylic functional groups. These hydrogels were characterized by nitrogen analysis, SEM, FTIR and also by water uptake studies as a function of time, temperature, pH, and the presence of additives like sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB). These hydrogels are environmentally sensitive. In the presence of surfactants, these hydrogels show micellization and swell to the maximum at the critical micellar concentration (CMC) of the surfactants. Lipase was immobilized on these hydrogels and the one exhibiting the maximum activity was further used as biocatalyst to explore nonconventional green routes for the synthesis of some known and novel vinyl monomers. Yields obtained have been high and the immobilized lipase show high reusability. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Gold/chitosan/pluronic composite nanoparticles for drug delivery
Authors: Oh Keun Sang , Kim Ree Sun , Lee Jinho , Kim Dongmin , Cho Sun Hang , Yuk Soon Hong
Published: March 2008

Composite nanoparticles were prepared and characterized as a sustained delivery system for paclitaxel, an anticancer drug. Gold nanoparticles were used as building blocks for constructing the composite nanoparticles. An ionic interaction between the anionic gold nanoparticles and cationic chitosan was induced to form the composite nanoparticles. Particle size analysis, field emission scanning electron microscopy, transmittance electron microscopy, and ultraviolet–visible were used to observe the formation of the composite nanoparticles. For the application of the composite nanoparticles as a drug carrier, paclitaxel was loaded into the composite nanoparticles, and the drug‐release pattern was observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Third‐order nonlinear optical properties and two‐photon absorption in polymers doped with p‐phenyl sydnone
Authors: Shettigar Seetharam , Umesh G. , Chandrasekharan K. , Rai Ganesh , Kalluraya B.
Published: March 2008

We report the measurements of the third‐order susceptibilities and two‐photon absorption in three different polymers doped with p‐phenyl sydnone moiety viz., 2‐benzylhydrazono‐5‐(3‐p‐tolylsydnone‐4‐yl)1,3,4,‐thiadiazine, which is recently synthesized and characterized, with the prospective of reaching a good compromise between processability and high nonlinear optical properties. The measurements were done using nano second Z‐scan at 532nm. The Z‐scan spectra reveal a large negative nonlinear refraction coefficient n2 of the order 10−14 cm2/W and a two‐photon absorption β, which is determined to be the order of cm/GW. The absorption cross section is 10−46 cm4 s/photon. The molecular second‐order hyperpolarizability in PMMA matrix was calculated to be 1.47 × 10−31 esu, comparable with stilbazolieum derivatives, a well‐known class of optical materials for photonics and biophotonics applications. The chromophore shows its optical power limiting behavior in all the three polymer matrices. All these results suggest that this moiety has potential for the application of all‐optical limiting and switching devices. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Nonwoven as heat barrier: Modeling of the efficiency of Carbtex fibers
Authors: Bourbigot Serge , Duquesne Sophie , Vannier Aurore , Delobel Rene
Published: March 2008

In this work, we examine the use of nonwoven (NW) as heat barrier to protect a metallic substrate. Carbtex fibers consisting in a thermoplastic core inside an oxidized outer shell (polyacrylonitrile or PAN fibers) are selected to make the NW. Measuring temperature profiles in a heat radiator test; it is revealed that Carbtex NW is an efficient heat barrier. A macroscopic model is then developed to simulate heat transfer in NW (considered as a porous medium) used as a protective heat barrier on aluminum plate. The model is validated comparing experimental results obtained by the heat radiator test and predicted values. The efficiency of NW layer is simulated varying different parameters characteristic of the NW (porosity and heat conductivity) and of the design (thickness of the layer). It is revealed to get good efficiency of the NW heat barrier that heat conductivity of the fibers is crucial to get superior performance as well as high porosity (higher than 0.5) associated with a reasonable thickness of NW (5–7 mm). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Comparison of specific interactions in P4VP/PSCA and PS4VP/PSCA blends and complexes
Authors: Bouslah Naima , Haddadine Nabila , Amrani Farouk , Hammachin Rabah
Published: March 2008

The compatibilization of an immiscible polymer system polystyrene/poly(4‐vinylpyridine) has been induced by the introduction of carboxylic acid groups within the polystyrene chains. Poly(styrene‐co‐cinnamic acid), PSCA, copolymers were used to prepare blends and complexes with poly(4‐vinylpyridine), P4VP, and in a second time with poly(styrene‐co‐4‐vinylpyridine), PS4VP, copolymer in order to reduce the density of the interacting groups. The miscibility of the systems has been ascertained by DSC, which revealed that both blends and complexes exhibit a single glass transition temperature indicating their single phase nature. The Tgs of the complexes of PS4VP with PSCA15, containing 15 mol % of cinnamic acid content, were higher than those of the corresponding blends indicating that stronger interpolymer interactions were developed in the complexes. Furthermore, the application of the Kwei equation suggested that P4VP interacts more strongly with PSCA15 than does PS4VP. FTIR spectra revealed the development of hydrogen bonding within the PS4VP/PSCA system and both hydrogen bonding and ionic interaction in the P4VP/PSCA blends whereas the same interactions were expected in both systems. This observation confirmed the stronger ability of P4VP to interact with PSCA copolymer. The viscosimetric study showed both positive and negative deviations of the reduced viscosity of the blends from the additivity law confirming the presence of specific interactions within the blend solutions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
TAROT: Robotic observatories for gamma‐ray bursts and other sources
Authors: Klotz A. , Vachier F. , Böer M.
Published: March 2008

TAROT (Télescopes à Action Rapide pour les Objets Transitoires) are two robotic observatories designed to observe the early optical counterpart of gamma‐ray bursts (GRBs) sources. As GRBs do not occur often, we use TAROT to observe other celestial targets: variable stars, minor‐planets, supernovae, etc. In this paper we present the software tools presently used to manage the observations and to process and archive the data. We present also CADOR (Coordination et Analyse des Données des Observatoires Robotiques) which will centralize virtual observatory services associated to both TAROT telescopes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Grid integration of robotic telescopes
Authors: Breitling F. , Granzer T. , Enke H.
Published: March 2008

Robotic telescopes and grid technology have made significant progress in recent years. Both innovations offer important advantages over conventional technologies, particularly in combination with one another. Here, we introduce robotic telescopes used by the Astrophysical Institute Potsdam as ideal instruments for building a robotic telescope network. We also discuss the grid architecture and protocols facilitating the network integration that is being developed by the German AstroGrid‐D project. Finally, we present three user interfaces employed for this purpose. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resource discovery with the VO registry
Authors: Graham M.J.
Published: March 2008

This article describes the VO registry concept and how it can be used to find resources – data sets, services and infrastructure – to support followup activities. It also discusses how VOEvent infrastructure components can be incorporated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Palomar‐Quest digital synoptic sky survey
Authors: Djorgovski S.G. , Baltay C. , Mahabal A.A. , Drake A.J. , Williams R. , Rabinowitz D. , Graham M.J. , Donalek C. , Glikman E. , Bauer A. , Scalzo R. , Ellman N. , Jerke J.
Published: March 2008

We describe briefly the Palomar‐Quest (PQ) digital synoptic sky survey, including its parameters, data processing, status, and plans. Exploration of the time domain is now the central scientific and technological focus of the survey. To this end, we have developed a real‐time pipeline for detection of transient sources.We describe some of the early results, and lessons learned which may be useful for other, similar projects, and time‐domain astronomy in general. Finally, we discuss some issues and challenges posed by the real‐time analysis and scientific exploitation of massive data streams from modern synoptic sky surveys. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Integrating VOEvent into the ground‐based O/IR system: A case study at NOAO
Authors: Smith R.C. , Seaman R. , Warner P.
Published: March 2008

In this article we describe a case study of how NOAO is considering improving its management of Target‐of‐Opportunity (ToO) observations by integrating VOEvent into the flow of activities. We believe that using VOEvent to help document and track the use of ToO time will improve the user experience of ToOs at NOAO. It will also greatly aid in the management of the process and of the resulting data, allowing us to better track the ownership and provenance of the data and any resulting data products. Finally, it will provide an important method of archival access to the data and data “collections,” which might include not only processed data from a single VOEvent triggered observation but could also include multiple observations traceable to a single (or set of related) VOEvents. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thread safe astronomy
Authors: Seaman R.
Published: March 2008

Observational astronomy is the beneficiary of an ancient chain of apprenticeship. Kepler's laws required Tycho's data. As the pace of discoveries has increased over the centuries, so has the cadence of tutelage (literally, “watching over”). Naked eye astronomy is thousands of years old, the telescope hundreds, digital imaging a few decades, but today's undergraduates will use instrumentation yet unbuilt – and thus, unfamiliar to their professors – to complete their doctoral dissertations. Not only has the quickening cadence of astronomical data‐taking overrun the apprehension of the science within, but the contingent pace of experimental design threatens our capacity to learn new techniques and apply them productively. Virtual technologies are necessary to accelerate our human processes of perception and comprehension to keep up with astronomical instrumentation and pipelined dataflows. Necessary, but not sufficient. Computers can confuse us as efficiently as they illuminate. Rather, as with neural pathways evolved to meet competitive ecological challenges, astronomical software and data must become organized into ever more coherent ‘threads’ of execution. These are the same threaded constructs as understood by computer science. No datum is an island. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mining marine shellfish wastes for bioactive molecules: Chitin and chitosan ndash; Part A: extraction methods
Authors: Hayes Maria , Carney Brian , Slater John , Brück Wolfram
Published: March 2008

Legal restrictions, high costs and environmental problems regarding the disposal of marine processing wastes have led to amplified interest in biotechnology research concerning the identification and extraction of additional high grade, low‐volume by‐products produced from shellfish waste treatments. Shellfish waste consisting of crustacean exoskeletons is currently the main source of biomass for chitin production. Chitin is a polysaccharide composed of N‐acetyl‐D‐glucosamine units and the multidimensional utilization of chitin derivatives including chitosan, a deacetylated derivative of chitin, is due to a number of characteristics including: their polyelectrolyte and cationic nature, the presence of reactive groups, high adsorption capacities, bacteriostatic and fungistatic influences, making them very versatile biomolecules. Part A of this review aims to consolidate useful information concerning the methods used to extract and characterize chitin, chitosan and glucosamine obtained through industrial, microbial and enzymatic hydrolysis of shellfish waste.
Application of proteomics in biotechnology – Microbial proteomics
Authors: Josic Djuro , Kovač Spomenka
Published: March 2008

The genomes of most economically important microbial cells are already sequenced and proteomic technologies can be applied during various process development steps, starting with the selection and optimization of the functions of the industrial strains, application of the knowledge of cell function in response to the changes of production parameters, validation of the downstream processing, and thorough characterization of the final product. Unfortunately, there are only a few direct examples in the literature that present the optimization of the production process based on proteomics. In this review, we discuss the potential of this technology for the design of future bioprocesses and for optimization of existing ones.
Glycoengineering of the methylotrophic yeast Hansenula polymorpha for the production of glycoproteins with trimannosyl core N‐glycan by blocking core oligosaccharide assembly
Authors: Oh Doo‐Byoung , Park Jeong‐Seok , Kim Moo Woong , Cheon Seon Ah , Kim Eun Jung , Moon Hye Yun , Kwon Ohsuk , Rhee Sang Ki , Kang Hyun Ah
Published: March 2008

The initial lipid‐linked oligosaccharide Glc3Man9GlcNAc2‐dolichyl pyrophosphate (Dol‐PP) for N‐glycan is synthesized and assembled at the membrane of the endoplasmic reticulum (ER) and subsequently transferred to a nascent polypeptide by the oligosaccharide transferase complex. We have identified an ALG3 homolog (HpALG3) coding for a dolichyl‐phosphate‐mannose dependent α‐1,3‐mannosyltransferase in the methylotrophic yeast Hansenula polymorpha. The detailed analysis of glycan structure by linkage‐specific mannosidase digestion showed that HpALG3 is responsible for the conversion of Man5GlcNAc2‐Dol‐PP to Man6GlcNAc2‐Dol‐PP, the first step to attach a mannose to the lipid‐linked oligosaccharide in the ER. The N‐glycosylation pathway of H. polymorpha has been remodeled by deleting the HpALG3 gene in the Hpoch1 null mutant strain blocked in the yeast‐specific outer mannose chain synthesis and by introducing an ER‐targeted Aspergillus saitoi α‐1,2‐mannosidase gene. This glycoengineered H. polymorpha strain produced glycoproteins mainly containing trimannosyl core N‐glycan (Man3GlcNAc2), which is the common core backbone of various human‐type N‐glycans. The results demonstrate the high potential of H. polymorpha to be developed as an efficient expression system for the production of glycoproteins with humanized glycans.
A PCR‐based strategy to generate yeast strains expressing endogenous levels of amino‐terminal epitope‐tagged proteins
Authors: Booher Keith R. , Kaiser Peter
Published: March 2008

An epitope tag introduced to a gene of interest (GOI) greatly increases the ease of studying cellular proteins. Rapid PCR‐based strategies for epitope tagging a protein's C‐terminus at its native gene locus are widely used in yeast. C‐terminal epitope tagging is not suitable for all proteins, however. Epitope tags fused to the C‐terminus can interfere with function of some proteins or can even be removed by C‐terminal protein processing. To overcome such problems, proteins can be tagged with epitopes at their amino‐termini, but generating yeast strains expressing N‐terminal epitope tagged genes under control of the endogenous promoter at the native locus is comparatively more difficult. Strategies to introduce N‐terminal epitope tags have been reported previously but often introduce additional sequences other than the epitope tag into the genome. Furthermore, N‐terminal tagging of essential genes by current methods requires formation of diploid strains followed by tetrad dissection or expression of an additional copy of the GOI from a plasmid. The strategies described here provide a quick, facile means of epitope tagging the N‐terminus of both essential and nonessential genes in a two‐step PCR‐based procedure. The procedure has the significant advantage of leaving tagged genes under the control of their endogenous promoters, and no additional sequences other than the epitope tag encoding nucleotides are inserted into the genome.
Systematic review and meta-analysis of the effect of portal triad clamping on outcome after hepatic resection
Authors: Rahbari N N , Wente M N , Schemmer P , Diener M K , Hoffmann K , Motschall E , Schmidt J , Weitz J , Büchler M W
Published: March 2008

Background

The effect of portal triad clamping (PTC) on outcome after hepatic resection is uncertain.

Methods

A systematic literature search was conducted to detect randomized controlled trials (RCTs) assessing the effectiveness and safety of PTC alone and of PTC with ischaemic preconditioning (IPC) of the liver. Studies on clamping of the inferior vena cava or hepatic veins were excluded. Endpoints included postoperative overall morbidity and mortality, cardiopulmonary and hepatic morbidity, blood loss, transfusion rates and alanine aminotransferase (ALT) levels. Meta-analyses were performed using a random-effects model.

Results

Eight RCTs published between 1997 and 2006 containing a total of 558 patients were eligible for final analysis. The design of the identified studies varied considerably. Analyses of endpoints revealed no difference between intermittent PTC and no PTC. Meta-analyses of PTC with and without previous IPC revealed no differences, but postoperative ALT levels were significantly lower with IPC.

Conclusion

On currently available evidence, the routine use of PTC does not offer any benefit in perioperative outcome after liver resection. It cannot be recommended as a standard procedure.
Iron Chelates of 2,2′‐Bidipyrrin: Stable Analogues of the Labile Iron Bilins
Authors: Bröring Martin , Köhler Silke , Link Stephan , Burghaus Olaf , Pietzonka Clemens , Kelm Harald , Krüger Hans‐Jörg
Published: March 2008

A unique series of halogenidoiron(III) complexes of the open‐chain tetrapyrrolic ligand 2,2′‐bidipyrrin (bpd) ([FeX(bdp)] X=F, Cl, Br, I) was prepared from simple pyrrolic and bipyrrolic precursors and iron chloride by a one‐pot condensation/metalation strategy, followed by salt metathesis with CsF, LiBr, or NaI. Crystallographic analysis revealed that in all cases the 2,2′‐bidipyrrin ligand is forced to reside in a helical conformation when bound to the iron atom. Whereas the extremely sensitive fluorido derivative was isolated as a CsF adduct and forms 1D polymeric chains in the solid state, the more stable chlorido, bromido, and iodido derivatives crystallize as discrete monomeric molecules with a distorted pentacoordinate iron(III) ion in an intermediate spin ground state. Magnetic susceptibility measurements and Mössbauer data of the compounds are in agreement with this interpretation. In solution, however, all the compounds are pentacoordinate with the iron atom in the high‐spin (S=5/2) state and dynamic with respect to helix inversion. In the presence of air, the iron chelates react stepwise with the nucleophiles methanol and imidazolate at the tetrapyrrole terminal α,ω‐positions, presumably through the hexacoordinate species [Fe(bdp)(MeOH)2]+ and [Fe(im)2(bdp)]−, respectively. The successive increase of strain at these positions results in increasingly labile intermediates that spontaneously release the iron ion from the mono‐ or disubstituted tetrapyrrole ligands.
Determination of ternary solutions concentration in liquid–liquid extraction by the use of attenuated total reflectance‐Fourier transform infrared spectroscopy and multivariate data analysis
Authors: Gallardo‐Velázquez T. , Osorio‐Revilla G. , Cárdenas‐Bailón F. , Beltrán‐Orozco M. C.
Published: March 2008

A simple and rapid Fourier transform infrared‐attenuated total reflectance (FTIR‐ATR) spectroscopic chemometric method was developed to determine the concentration of solute and solvent in the raffinate layer in a liquid–liquid extraction (LLE) process using partial least squares (PLS) regression. Five type I extraction systems were used with different solute–solvent affinity. The developed model (correlation coefficient from 0.91 to 0.99) was validated with known concentration samples, and in all cases the difference was not larger than 0.5%w. The LLE for the five extraction systems was carried out in a three‐stage crosscurrent extraction process, quantifying the solute and solvent with the chemometric model developed. The results were used to calculate the stage and overall stage efficiencies for the five systems. This method showed to be fast and precise for the quantification of ternary systems in LLE.
Solid phase extraction of chromium (VI) from aqueous solutions by adsorption of its diphenylcarbazide complex on an alumina column
Authors: Rajesh N. , Agarwal Vikas , Aarthy S.
Published: March 2008

A simple method has been developed for the solid phase extraction of chromium (VI) based on the adsorption of its diphenylcarbazide (DPC) complex on an alumina column. The effect of various parameters such as acidity, stability of the column, sample volume, and interfering ions have been studied in detail. The adsorbed complex could be easily desorbed using sulphuric acid and the concentration of chromium has been established using atomic absorption spectrophotometry and visible spectrophotometry. The calibration graph was linear in the range of 0–1 µg/mL chromium (VI) with a detection limit of 4 µg/L. A highest preconcentration factor of 125 could be obtained for 5000 mL sample volume using glass wool as support for alumina. Chromium (VI) could be effectively separated from other ions such as zinc, nickel, copper, chloride, sulphate, and nitrate and the method has been successfully applied to study the recovery of chromium in spiked well water and tap water samples.
Prediction of equilibrium solubility of CO2 in aqueous alkanolamines using differential evolution algorithm
Authors: Kundu M. , Chitturi A. , Bandyopadhyay S. S.
Published: March 2008

The design of sour‐gas treating processes with alkanolamine solvents requires knowledge of the vapour–liquid equilibrium (VLE) of the aqueous acid gas–alkanolamine systems. Representation of the experimental data with a thermodynamically rigorous model is required, so that one can systematically correlate and predict the VLEs of these systems. The modified Clegg–Pitzer equations have been used to correlate and predict the VLE of CO2 in the aqueous N‐methyldiethanolamine (MDEA) and 2‐amino‐2‐methyl‐1‐propanol (AMP) systems. Differential evolution (DE), an evolutionary computational technique, has been used for parameter estimation of the developed VLE model in an effort to predict the VLE of CO2 in aqueous MDEA and AMP solutions with a comparable accuracy to that by using the non‐traditional simulated annealing (SA) and deterministic technique like Levenberg–Marquardt (LM), if not better. In this work, the DE/rand‐best/1/bin strategy has been used for finding near global minimum solutions to the multivariable optimization problem as a part of the numerical solution of the developed model.
In vitro characterization of phosphatidylglyceroglycerol‐based thermosensitive liposomes with encapsulated 1H MR T1‐shortening gadodiamide
Authors: Wang Tungte , Hossann Martin , Reinl Herbert M. , Peller Michael , Eibl Hansjoerg , Reiser Maximilian , Issels Rolf D. , Lindner Lars H.
Published: March 2008

Thermosensitive liposomes (TSL) with encapsulated proton (1H) magnetic resonance (MR) contrast agents have been proposed for noninvasive online temperature monitoring during tumor treatment using chemotherapy combined with hyperthermia (HT). The technique exploits the fact that water exchange between the TSL interior and exterior is increased and/or the encapsulated 1H MR contrast agent is released near the gel‐to‐liquid crystalline phase transition temperature (Tm) of TSL and thus shortens the 1H MR relaxation time of tissue. In this work, newly developed, phosphatidylglyceroglycerol (DPPGOG)‐based TSL with encapsulated 1H MR longitudinal relaxation time (T1)‐shortening gadodiamide (Gd‐DTPA‐BMA) were characterized in vitro by measuring the temperature dependence of the T1 of these gadodiamide‐containing DPPGOG‐TSL samples between 30 and 50°C. The measurements revealed that the T1 nonlinearly slightly decreased with increasing temperature from 30 to 37°C, mainly due to increased water exchange between the gadodiamide‐containing DPPGOG‐TSL interior and exterior with the exception of negligible gadodiamide release. This implies that gadodiamide‐containing DPPGOG‐TSL were stable at temperatures ≤37°C, which was also confirmed by an independent stability study. From 37 to 44°C, the T1 nonlinearly markedly decreased with increasing temperature since encapsulated gadodiamide was rapidly released. Above 44°C, gadodiamide was completely released and the T1 was directly proportional to temperature while heated from 44 to 50°C and cooled from 50 to 30°C, respectively. Additionally, gadodiamide release was theoretically quantified and this calculated concentration was consistent with the actually released amount directly obtained from the cooling course of empty DPPGOG‐TSL with completely released gadodiamide. Copyright © 2008 John Wiley & Sons, Ltd.
Systematic review of statistical methods used in molecular marker studies in cancer
Authors: Vickers Andrew J. , Jang Kwang , Sargent Daniel , Lilja Hans , Kattan Michael W.
Published: March 2008

BACKGROUND.

There is wide interest in the use of molecular markers for the early detection of cancer, the prediction of disease outcome, and the selection of patients for chemotherapy. Despite significant and increasing research activity, to the authors' knowledge only a small number of molecular markers have been successfully integrated into clinical practice. In the current study, the experimental designs and statistical methods used in contemporary molecular marker studies are reviewed, particularly with respect to whether these evaluated a marker's clinical value.

METHODS.

MEDLINE was searched for studies that analyzed an association between a cancer outcome and a marker involving chemical analysis of body fluid or tissue. For each article, data were extracted regarding patients, markers, type of statistical analysis, and principal results.

RESULTS.

The 129 articles eligible for analysis included a very large variety of molecular markers; the total number of markers was larger than the number of articles. Only a minority of articles (47 articles; 36%) incorporated multivariate modeling in which the marker was added to standard clinical variables, and only a very small minority had any measure of predictive accuracy (14 articles; 11%). No article used decision analytic methods or experimentally evaluated the clinical value of a marker. Correction for overfit was also rare (3 articles).

CONCLUSIONS.

Statistical methods in molecular marker research have not focused on the clinical value of a marker. Attention to sound statistical practice, in particular the use of statistical approaches that provide clinically relevant information, will help maximize the promise of molecular markers for care of the cancer patient. Cancer 2008. © 2008 American Cancer Society.
Development of In Situ Electrochemical Scanning Electron Microscopy with Ionic Liquids as Electrolytes
Authors: Arimoto Satoshi , Oyamatsu Daisuke , Torimoto Tsukasa , Kuwabata Susumu
Published: March 2008

We report that ionic liquids (ILs) can be observed by electron microscopy without any charging of the liquid. Based on this, we present an in situ electrochemical scanning electron microscopy (in situ ECSEM) system. The key technology that enables in situ ECSEM is that charges can be removed from an IL by grounding it with a Pt wire, even if the IL is in an insulating glass cell. As a first demonstration, we describe the redox reaction of a polypyrrole (PPy) film accompanied by changes in its thickness when it is polarized by the film‐deposited Pt electrode in the IL. Furthermore, energy‐dispersive X‐ray fluorescence (EDX) analysis can be employed for the electrode polarized in the IL. The component analysis by EDX of PPy in an IL containing K+ as a marker, reveals doping of electrolyte cations into the PPy film upon the latter′s reduction and dedoping of cations from the film upon oxidation.
Back to basics: Validation of automated as compared to manual slide staining in the cytopathology laboratory
Authors: Haack Lori A. , Selvaggi Suzanne M.
Published: March 2008

Regulatory agencies on laboratory accreditation require that a laboratory validate and document an instrument's functionality in its own specific environment, including the capability of the instrument to replace existing processes. Instruments without manufacturer‐provided validation protocols must still undergo validation with documentation of the specific method used. This study was performed to validate the Sakura Tissue‐Tek® DRS™ 2000 automated slide stainer. Diagn. Cytopathol. 2008;36:199–201. © 2008 Wiley‐Liss, Inc.
Cytologic features of meningiomas on crush preparations: A review
Authors: Siddiqui Momin T. , Mahon Brett M. , Cochran Elizabeth , Gattuso Paolo
Published: March 2008

Meningiomas are rarely subjected to aspiration, however, since they may occur outside the central nervous system, it is important to recognize their cytologic features. The goal of this study was to examine the cytologic features of meningiomas in crush preparations and cytologic imprints prepared at the time of frozen section. A total of 97 cases of meningiomas evaluated intraoperatively by frozen section with concomitant crush preparation and cytologic imprint were reviewed to assess their cytologic features. The cytologic features of meningiomas identified in our study are cohesive syncitial clusters of cells with ill‐defined boundaries. The nuclei are oval and may be eccentrically placed, along with small central nucleoli. The cytologic features may not reflect the histologic subtype. The psammomatous variant can however be easily recognized in touch preps/imprints. The presence of nuclear anaplasia, macronucleoli, mitotic activity, and sheet‐like growth may suggest an atypical meningioma. In conclusion, the cytologic features identified would be helpful in diagnosis of meningiomas, especially in unusual locations. Diagn. Cytopathol. 2008;36:202–206. © 2008 Wiley‐Liss, Inc.
The effects of early isolation on sexual behavior and c‐fos expression in naïve male long‐evans rats
Authors: Akbari E. M. , Budin R. , Parada M. , Fleming A. S.
Published: March 2008

Previous findings have demonstrated that the maternal environment is important for the development of male sexual behavior. The present study examined the effects of complete early life isolation and replacement ‘stroking’ stimulation on male sexual behavior and neural activation as seen by Fos immunoreactivity (Fos‐IR). Animals were either artificially reared (AR) with minimal (AR‐MIN) or maximal (AR‐MAX) body simulation, or maternally reared (MR). In adulthood, animals were either given an exposure to an estrous female (EXP) or left undisturbed (NoEXP). No significant effects of early development were found in sexual behavior; however differences in activation in response to this exposure were observed. AR‐MIN animals showed lower Fos‐IR in the medial preoptic area and the ventromedial hypothalamus compared to MR animals. AR‐MAX animals were not significantly different from either condition. These findings demonstrate that although there are no differences in the quality of the first copulatory exposure between AR and MR animals, the brain's response to this exposure differs in sites within the brain that subserve sexual behavior. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 298–306, 2008.
Diamagnetic π‐Dimers of the [1,2,5]Thiadiazolo[3,4‐c][1,2,5]thiadiazolidyl Radical Anion in the Crystalline State: Preparation and X‐ray Crystal Structure of a [(Me2N)2CC(NMe2)2]2+[(C2N4S2)2]2– Salt
Authors: Gritsan Nina P. , Lonchakov Anton V. , Lork Enno , Mews Ruediger , Pritchina Elena A. , Zibarev Andrey V.
Published: March 2008

Chemical reduction of [1,2,5]thiadiazolo[3,4‐c][1,2,5]thiadiazole (2) with 1,1,2,2‐tetrakis(dimethylamino)ethene (3) leads to the [3]2+[12]2– salt (4) whose X‐ray crystal structure reveals diamagnetic π‐dimers of the [1,2,5]thiadiazolo[3,4‐c][1,2,5]thiadiazolidyl radical anion (1). The interplanar separation of 324.5 pm in the [12]2– dimers is significantly shorter than the sum of the isotropic van der Waals radii of two S atoms of 348–358 pm. CASSCF calculations suggest that the largest contributor to the singlet ground state of these π‐dimers is the closed‐shell electronic configuration, although a noticeable contribution from a configuration with a singlet biradical character was also found. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and Photoluminescence Properties of Heteroleptic Europium(III) Complexes with Appended Carbazole Units
Authors: Zheng Youxuan , Cardinali Francois , Armaroli Nicola , Accorsi Gianluca
Published: March 2008

Two europium complexes {Eu·dbm·carb·phen = tris[1‐{[6‐(9H‐carbazol‐9‐yl)hexoxy]phenyl}‐3‐{[6‐(9H‐carbazol‐9‐yl)hexoxy]phenyl}propane‐1,3‐dione](1,10‐phenanthroline)europium(III), Eu·dbm·carb·bath = tris[1‐{[6‐(9H‐carbazol‐9‐yl)hexoxy]phenyl}‐3‐{[6‐(9H‐carbazol‐9‐yl)hexoxy]phenyl}propane‐1,3‐dione](bathophenanthroline)europium(III)} and their reference compounds were synthesized and characterized. Each complex contains three different chromophores: carbazole (carb), phenanthroline (phen) (or bathophenanthroline, bath) and dibenzoylmethane (dbm) units. The luminescence properties investigated in dichloromethane solution and in solid matrix show that the carbazole moiety is a better sensitizer for the metal‐centred emitting states of the EuIII ion compared to the dibenzoylmethane and phenanthroline units. Furthermore, the charge‐transporting properties of the carbazole moieties appear to be appealing when integrated into the emitting units. Finally, the high number of appended carbazole units confers a strong light‐harvesting character to the structure.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)