bluuebunny/crossref_metadata_2025_split huggingface dataset:
A dual fluorescent/MALDI chip platform for analyzing enzymatic activity and for protein profiling
Authors: Halim Vincentius A. , Muck Alexander , Hartl Markus , Ibáñez Alfredo J. , Giri Ashok , Erfurth Florian , Baldwin Ian T. , Svatoš Aleš 
Published: December 2008

AbstractBeing able to rapidly and sensitively detect specific enzymatic products is important when screening biological samples for enzymatic activity. We present a simple method for assaying protease activity in the presence of protease inhibitors (PIs) by measuring tryptic peptide accumulation on copolymer pMALDI target chips using a dual fluorescence/MALDI‐TOF‐MS read‐out. The small platform of the chip accommodates microliter amounts of sample and allows for rapid protein digestion. Fluorescamine labeling of tryptic peptides is used to indicate the proteolytic activity and is shown to be an affordable, simple process, yielding a strong fluorescence signal with a low background. Subsequent MALDI‐TOF‐MS analysis, performed in the same sample well, or in a parallel well without adding fluorescamine, detects the specific tryptic peptides and provides confidence in the assay. The dual read‐out method was applied to screen the inhibition activity of plant PIs, components of plant defense against herbivores and pathogens. Extracts of PIs from Solanum nigrum and trypsin were applied together to a pMALDI chip on which a suitable substrate was adsorbed. The fluorescence and MALDI‐TOF‐MS signal decrease were associated with the inhibitory effect of the PIs on trypsin. The developed platform can be modified to screen novel protease inhibitors, namely, those potentially useful for treating or preventing infection by viruses, including HIV and hepatitis C.
British Association for Psychopharmacology Servier satellite meeting: Sleep disturbance
Authors: Chaplin Steve 
Published: December 2008

AbstractThe issue of sleep disturbance, its association with depression and implications for treatment were discussed at a Servier satellite symposium at the Summer meeting of the
British Association for Psychopharmacology in Harrogate. Medical writer Steve Chaplin reports. Copyright © 2008 Wiley Interface Ltd
Photochromism of dihydroindolizines part X. Photo‐responsive self‐assembling organogelators based on photochromic dihydroindolizines and 11‐aminoundecanoic acid (AUDA)
Authors: Ahmed Saleh A. , Moussa Ziad , Al‐Raqa Shaya Y. , Alamry Saleh N. 
Published: December 2008

AbstractMulti‐addressable photophysical properties of new synthesized photochromic materials based on photochromic dihydroindolizine system (DHI) covalently linked to N‐acyl‐11 aminoundecanoic acid (AUDA) or to its sodium salt or to its ester, through an amidic or urethane linkage have been studied. The DHI skeleton in these compounds is substituted in both the fluorene part (region A) or in the heterocyclic base (region B) with the gelling moieties. These molecules have been designed to respond to their environment. Interestingly, they are shown to act as efficient gelators for polar organic fluids, water and obviously they exhibit a thermosensitive answer as low molecular mass organogelators. In these fluids, the aggregative properties are totally suppressed upon conversion to neutral carboxylic species. The gels of these carboxylate sodium salts are shown to be markedly affected by light irradiation. Supramolecular gelating assemblies can be disrupted by the photoinduced ring opening of the DHI subunit, so that the macroscopic flowing property is recovered. Upon a further thermal treatment, the system is reversibly converted back to the supramolecular network. Controlled gelation could be achieved using temperature, light, or acidity as external stimuli. These new synthesized photochromic gels with their multi‐addressable properties will find their applications as super photoresponsive materials. Developing and tuning of the photophysical properties of the synthesized compounds by the amide and urethane substituents in the 4‐position of the fluorene and pyridazine regions have been achieved. The absorption maxima (λmax) and the half‐lives (t1/2) of the colored betaines were detected in all cases using UV/VIS spectrophotometric measurements. Irradiation of DHI 12‐20 in CH2Cl2 or in acetonitrile solutions at ambient temperature with polychromatic light leads to the formation of red to red‐violet colored betaines 12′‐20′. The kinetics of the bleaching process of betaines 12′‐20′ to DHIs 12‐20 were found to take place in the second range (96‐218 s) and fit well the first order thermal back reaction. Some of these DHIs showed a photostability higher than that of the standard one. These interesting photophysical properties will help this family of compounds to find useful applications. Copyright © 2008 John Wiley & Sons, Ltd.
Density functional and spectroscopic studies of nitrogen inversion in substituted dizocilpines
Authors: Aliev Abil E. , Sinclair Alex J. , Zhou Shen , Wilden John D. , Caddick Stephen , Kullmann Dimitri M. , Rusakov Dmitri A. 
Published: December 2008

AbstractWhile developing a synthesis towards tagged dizocilpine (MK‐801) analogues, we observed highly restricted inversion of a nitrogen centre in a number hydroxylamines obtained as key intermediates. These compounds are shown to possess some of the structural elements which are expected to significantly hinder the nitrogen inversion, potentially leading to hydroxylamines with a chiral nitrogen centre. Free energy barriers (ΔG≠) of the nitrogen inversion were estimated to be ca. 22 kcal mol−1 at temperatures near 420 K using variable temperature NMR measurements in DMSO‐d6. Further density functional studies of a number model systems were undertaken in order to better rationalize the measured inversion barriers and follow the role of various structural factors in raising the barrier height of the nitrogen inversion process. Copyright © 2008 John Wiley & Sons, Ltd.
Quantitative structure–reactivity relationship studies on the catalyzed Michael addition reactions
Authors: Hemmateenejad Bahram , Sanchooli Mahmood , Mehdipour Ahmadreza 
Published: December 2008

AbstractQuantitative structure–reactivity relationship (QSRR) can be considered as a variant of quantitative structure–property relationship (QSPR) studies, where the chemical reactivity of reactants or catalysts in a specified chemical reaction is related to chemical structure. In this manner, the Michael addition of some different substrates using different catalysts (SDS, silica gel, and ZrOCl2) was subjected to structure–reactivity relationship, quantitatively. Multiple linear regression (MLR) and partial least square (PLS) were used to perform the QSRR analysis. The resulted models for different catalyzed reactions showed that the catalysts probably act in different mechanisms since the models obtained for the catalysts included different parameters from substrate and enones. Overall, it was found that the reactivity in Michael addition reactions is controlled by coulombic (dipole and charge) interactions as well as the orbital energetic parameters. In the presence of different catalysts, the relative importance of these parameters is changed and hence the catalytic activity is changed. Copyright © 2008 John Wiley & Sons, Ltd.
In vitrometabolism ofβ‐lapachone (ARQ 501) in mammalian hepatocytes and cultured human cells
Authors: Miao Xiu‐Sheng , Zhong Caiyun , Wang Yunxia , Savage Ronald E. , Yang Rui‐Yang , Kizer Darin , Volckova Erika , Ashwell Mark A. , Chan Thomas C. K. 
Published: December 2008

AbstractARQ 501 (3,4‐dihydro‐2,2‐dimethyl‐2H‐naphthol[1,2‐b]pyran‐5,6‐dione,β‐lapachone) is an anticancer agent, currently in multiple phase II clinical trials as monotherapy and in combination with other cytotoxic drugs. This study focuses onin vitrometabolism in cryopreserved hepatocytes from mice, rats, dogs and humans using [14C]‐labeled ARQ 501. Metabolite profiles were characterized using liquid chromatography/mass spectrometry combined with an accurate radioactivity counter. Ion trap mass spectrometry was employed for further structural elucidation. A total of twelve metabolites were detected in the mammalian hepatocytes studied; all of which but one were generated from phase II conjugation reactions. Ten of the observed metabolites were produced by conjugations occurring at the reducedortho‐quinone carbonyl groups of ARQ 501. The metabolite profiles revealed that glucuronidation was the major biotransformation pathway in mouse and human hepatocytes. Monosulfation was the major pathway in dog, while, in rat, it appears glucuronidation and sulfation pathways contributed equally. Three major metabolites were found in rats: monoglucuronide M1, monosulfate M6, and glucuronide‐sulfate M9. Two types of diconjugation metabolites were formed by attachment of the second glycone to an adjacent hydroxyl or to an existing glycone. Of the diconjugation metabolites, glucosylsulfate M10, diglucuronide M5, and glucuronide‐glucoside M11 represent rarely observed phase II metabolites in mammals. The only unconjugated metabolite was generated through hydrolysis and was observed in rat, dog and human hepatocytes. ARQ 501 appeared less stable in human hepatocytes than in those of other species. To further elucidate the metabolism of ARQ 501 in extrahepatic sites, its metabolism in human kidney, lung and intestine cells was also studied, and only monoglucuronide M1 was observed in all the cell types examined. Copyright © 2008 John Wiley & Sons, Ltd.
Liquid chromatography/negative ion atmospheric pressure photoionization mass spectrometry: a highly sensitive method for the analysis of organic explosives
Authors: Song Liguo , Bartmess John E. 
Published: December 2008

AbstractGas chromatography/mass spectrometry (GC/MS) is applied to the analysis of volatile and thermally stable compounds, while liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI‐MS) and liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) are preferred for the analysis of compounds with solution acid‐base chemistry. Because organic explosives are compounds with low polarity and some of them are thermally labile, they have not been very well analyzed by GC/MS, LC/APCI‐MS and LC/ESI‐MS. Herein, we demonstrate liquid chromatography/negative ion atmospheric pressure photoionization mass spectrometry (LC/NI‐APPI‐MS) as a novel and highly sensitive method for their analysis. Using LC/NI‐APPI‐MS, limits of quantification (LOQs) of nitroaromatics and nitramines down to the middle pg range have been achieved in full MS scan mode, which are approximately one order to two orders magnitude lower than those previously reported using GC/MS or LC/APCI‐MS. The calibration dynamic ranges achieved by LC/NI‐APPI‐MS are also wider than those using GC/MS and LC/APCI‐MS. The reproducibility of LC/NI‐APPI‐MS is also very reliable, with the intraday and interday variabilities by coefficient of variation (CV) of 0.2–3.4% and 0.6–1.9% for 2,4,6‐trinitrotoluene (2,4,6‐TNT). Copyright © 2008 John Wiley & Sons, Ltd.
Is Carotid Endarterectomy a Trainee Operation?
Authors: Lutz Hans‐Joachim , Michael R. , Gahl B. , Savolainen H. 
Published: December 2008

AbstractBackgroundRecent dramatic changes in surgical training resulting from working‐hour regulations may lead to lack of competence. Traditionally, carotid surgery has been the domain of specialists. This study was designed to compare the outcome of carotid endarterectomy performed by vascular surgical trainees versus vascular surgeon (VS).MethodsA retrospective study of 1,379 consecutive patients who underwent carotid endarterectomy as the sole procedure under local or general anesthesia (from 1995–2004) was performed. All patients were admitted to the intensive care unit for 24 hours. Trainees performed 475 (34.5%) and vascular specialists performed 904 (65.5%) operations.ResultsPatient characteristics with regard to preoperative neurological status were similar. Trainees operated on 61.4% symptomatic patients and VS on 56.8% (P = 0.09). Shunt use did not differ (16% trainee vs. 17.8% VS). Clamping time and total operating time were longer among trainees (41.9 vs. 33.5 min, P < 0.001; and 121.2 vs. 101.8 min, P < 0.001, respectively). Postoperative stroke and death rates (3.2% vs. 3.1% and 0.4% vs. 0.9%, respectively) did not differ. Peripheral nerve complications were more common among trainees (12.2% vs. 6.5%; P < 0.0001); 99.6% of these nerve injuries had resolved at 3 months’ follow‐up.ConclusionsCarotid endarterectomy can be performed safely by a trainee vascular surgeon when assisted and supervised by a specialist vascular surgeon.
Current Understanding and Potential Immunotherapy for HIV‐Associated Squamous Cell Carcinoma of the Anus (SCCA)
Authors: Marin‐Muller Christian , Li Min , Chen Changyi , Yao Qizhi 
Published: December 2008

AbstractSquamous cell carcinoma of the anus (SCCA) is a rare disease in the average population but is an increasing concern among immunocompromised individuals, such as the HIV‐seropositive. Coinfection with human papillomavirus (HPV) in this population is common. HPV infection is difficult to clear with a compromised immune system, which results in a greater risk of tumor development and a more aggressive progression of the disease. The recent approval of a prophylactic HPV vaccine for cervical cancer has sparked an interest in a search for improved immunotherapeutic multimodality therapies to combat anogenital tumors associated with the virus. In this review, we discuss the known mechanisms of action of HIV‐associated SCCA, examine the current treatments for the disease, and focus on the potential of an immunotherapeutic vaccine approach for both prophylactic and therapeutic application.
Linear Rashba Model of a Hydrogenic Donor Impurity in GaAs/GaAlAs Quantum Wells
Authors: Li Shu-Shen , Xia Jian-Bai 
Published: December 2008

Abstract
The Rashba spin-orbit splitting of a hydrogenic donor impurity in GaAs/GaAlAs quantum wells is investigated theoretically in the framework of effective-mass envelope function theory. The Rashba effect near the interface between GaAs and GaAlAs is assumed to be a linear relation with the distance from the quantum well side. We find that the splitting energy of the excited state is larger and less dependent on the position of the impurity than that of the ground state. Our results are useful for the application of Rashba spin-orbit coupling to photoelectric devices.
A Rapid Synthesis of Oriented Palladium Nanoparticles by UV Irradiation
Authors: Navaladian S , Viswanathan B , Varadarajan TK , Viswanath RP 
Published: December 2008

Abstract
Palladium nanoparticles of average size around 8 nm have been synthesized rapidly by UV irradiation of mixture of palladium chloride and potassium oxalate solutions. A rod-shaped palladium oxalate complex has been observed as an intermediate. In the absence of potassium oxalate, no Pd nanoparticles have been observed. The synthesized Pd nanoparticles have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selective area electron diffraction and energy dispersive analysis by X-rays (EDAX) analyses. XRD analysis indicates the preferential orientation of catalytically active {111} planes in Pd nanoparticles. A plausible mechanism has been proposed for the formation of anisotropic Pd nanoparticles.
Fatty Acid Biomarkers of Symbionts and Unusual Inhibition of Tetracosapolyenoic Acid Biosynthesis in Corals (Octocorallia)
Authors: Imbs Andrey B. , Demidkova Darya A. , Dautova Tatyana N. , Latyshev Nikolay A. 
Published: December 2008

AbstractSeven zooxanthellae‐free species of octocorals (the genera Acanthogorgia, Acabaria, Chironephthya, Echinogorgia, Menella, Ellisella, and Bebryce) and two zooxanthellate octocorals (the genera Paralemnalia and Rumphella) were examined to elucidate their fatty acid (FA) composition. Arachidonic (about 40% of the total FA) and palmitic acids were predominant in all the species studied. Seven furan FA (F‐acids) (up to 9.7%) were identified in the azooxanthellate octocorals. The main F‐acids were 14,17‐epoxy‐15‐methyldocosa‐14,16‐dienoic and 14,17‐epoxy‐15,16‐dimethyldocosa‐14,16‐dienoic acids. In all specimens of Bebryce studeri, C25–28 demospongic FA (about 20%) were identified. These FA reflect the presence of a symbiotic sponge in B. studeri and can be used as the specific markers for other corals. A significant difference (P < 0.01) between azooxanthellate and zooxanthellate corals was found for odd‐chain and methyl‐branched saturated FA, 18:1n‐7, and 7‐Me‐16:1n‐10; that indicated the presence of an advanced bacterial community in azooxanthellate corals. The zooxanthellate species were distinguished by significant amounts of 18:3n‐6, 18:4n‐3, and 16:2n‐7 acids, which are proposed as the markers of zooxanthellae in soft corals. Contrary to the normal level of 24:5n‐6 (9.4%) and 22:4n‐6 (0.6%), unexpected low concentrations of 24:5n‐6 (0.4%) accompanied by a high content of 22:4n‐6 (up to 11.9%) were detected in some specimens. The presence of an unknown factor in octocorals, specific for n‐6 PUFA, which inhibited elongation of 22:4n‐6 to 24:4n‐6, is conjectured.
Optimization of Synthetic Conditions for the Preparation of Dihomo‐γ‐Linolenic Acid from γ‐Linolenic Acid
Authors: Xue Gang , Liu Fengxia , Wang Ying , Huang Kaixun 
Published: December 2008

AbstractOrthogonal experiments were employed to optimize the correlated parameters of reduction, sulfonation, substitution and hydrolysis. These reactions were used to convert γ‐linolenic acids into dihomo‐γ‐linolenic acids (DGLA). For the reduction, the best reaction conditions were at 35 °C for 4.5 h with LiAlH4 and γ‐linolenic acid (in the ratio of 40 g:100 g); for the sulfonation, reaction at 29 °C for 3.5 h with 150 g γ‐linolenic alcohol and 65 mL mesyl chloride, then the water phase being extracted with dichloromethane (3 × 100 mL); for the substitution, the reaction at 80 °C for 2.5 h with metallic sodium and sulfonate (at a ratio of 8 g:100 g); and for the hydrolysis, reaction at 80 °C for 2.5 h with NaOH and dihomo dioate (at a ratio of 50 g:100 g). The four reactions gave yields that exceeded 90% for each step. Finally, crystallization and decarboxylation provided DGLA in an overall yield of 60% and >95% purity.
Phospholipid Composition of Jatropha curcus Seed Lipids
Authors: Rao Kotte Sagar , Chakrabarti Pradosh Prasad , Rao B. V. S. K. , Prasad R. B. N. 
Published: December 2008

AbstractJatropha curcus L. oil has emerged as one of the most important raw materials for biodiesel production. However, no detailed study has been reported on characterizing the lipid constituents of jatropha oil. The present study revealed that the total oil content of jatropha seeds was 32% with a composition of 97.6% neutral lipids, 0.95% glycolipids and 1.45% phospholipids. The fatty acid composition of total lipids, neutral lipids, phospholipids and glycolipids was also determined and found to contain oleic acid (18:1) and linoleic acids (18:2) as major fatty acids. The phospholipids fraction was further characterized and quantified and found to contain phosphatidyl choline (PC) 60.5%, phosphatidyl inositol (PI) 24% and phosphatidyl ethanolamine (PE) 15.5%. The fatty acid composition and the positional distribution of the fatty acids of individual phospholipids were also reported.
Utilization of Olive‐Pomace Oil for Enzymatic Production of Cocoa Butter‐like Fat
Authors: Çiftçi Ozan Nazım , Fadıloğlu Sibel , Göğüş Fahrettin 
Published: December 2008

AbstractRefined olive‐pomace oil (ROPO) was utilized as a source for the production of a cocoa butter (CB)‐like fat. Immobilized sn‐1,3 specific lipase‐catalyzed acidolysis of ROPO with palmitic (PA) and stearic (SA) acids was performed at various substrate mole ratios (ROPO:PA:SA) to produce major triacylglycerols (TAGs) of CB. Products obtained for various substrate mole ratios were compared to a commercial CB in terms of TAG content, melting profile, solid fat content (SFC) and microstructure. The fat produced at a substrate mole ratio of 1:2:6 was the most similar to CB. The product contained 11% POP, 21.8% POS, 15.7% SOS while commercial CB contained 18.9% POP, 33.1% POS and 24.7% SOS. The product had a melting peak of 29.9 °C while CB had one of 28.5 °C. Polarized light microscope (PLM) images showed that fat crystal network microstructures of this product and CB were very similar.
HDL concentration, lipid transfer to HDL, and HDL size in normolipidemic nonobese menopausal women
Authors: Giribela Arícia H. , Melo Nilson R. , Latrilha Maria C. , Baracat Edmundo C. , Maranhão Raul C 
Published: December 2008

AbstractObjectiveTo determine the impact of menopause on lipid transfer from donor lipoproteins to high‐density lipoproteins (HDLs)—a process that is related to the protective function of HDL—and the size of HDL particles.MethodPlasma from 22 premenopausal and 18 postmenopausal nonobese, normolipidemic women paired for age (40–50 years) was incubated in an artificial nanoemulsion labeled with radioactive lipids. Then the HDL fraction was assessed for radioactivity; the percentage of radioactive lipids transferred from the nanoemulsion to HDL was determined; and the size of HDL particles was measured by laser light scattering.ResultsThere were no differences between the 2 groups in serum concentration of HDL cholesterol (61 ± 12 mg/dL vs 61 ± 14 mg/dL) or apolipoprotein A1 (1.5 ± 0.3 g/L vs 1.5 ± 0.2 g/L); lipid transfer to HDL; or size of HDL particles (8.8 ± 0.8 vs 9.0 ± 0.5 nm).ConclusionMenopause was not found to affect HDL cholesterol plasma concentration, lipid transfer to HDL, or size of HDL particles in normolipidemic nonobese women.
NASA's Mars lander completes mission
Authors: Showstack Randy 
Published: December 2008

After 5 months of providing scientists with a better understanding of Mars, and 2 months beyond the planned operational life, instruments on NASA's Phoenix Mars Lander are no longer receiving sufficient energy to operate due to an autumnal decline in sunlight reaching the lander's solar arrays, the agency announced on 10 November. The lander's last signal was received on 2 November, and scientists will be listening for any additional signals should the lander revive.Since touching down on Mars on 25 May 2008, lander instruments verified the presence of water ice in the Martian subsurface. The lander has taken more than 25,000 pictures, among other accomplishments. Transmitted data have helped scientists learn more about the planet's arctic environment and whether it has ever been favorable for microbes. “Phoenix has given us some surprises, and I'm confident we will be pulling more gems from this trove of data for years to come,” said Phoenix principal investigator Peter Smith of the University of Arizona, in Tucson, which leads the mission.
Progress in Understanding Earth's Radiation Belts, Radiation Belts Saint Petersburg; Saint Petersburg, Russia, 4–6 August 2008
Authors: Goldstein Jerry , Shprits Yuri 
Published: December 2008

Fifty years after their discovery, Earth's radiation belts are an enduring major challenge, owing to the complex, interdependent phenomena controlling these particles, and motivated by the enormous role of space technology in our society. The recent Radiation Belts Saint Petersburg (RBSPb) workshop explored how to meet this challenge.Considerable discussion focused on learning more from observations, especially by revisiting existing spacecraft data sets with new analysis techniques or updated paradigms. New techniques were reported, such as extraction of energetic electron data from signal contamination in proton detectors and conversion of auroral proton images into global wave proxies. New insight concerning global aspects of the system (e.g., plasmaspheric wave‐particle interactions) enables less ambiguous interpretation of local measurements.