bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlled Garegg Conditions for Selective Iodination on Pyranose Templates
Authors: Simao Ana‐Catarina , Silva Sandrina , Rauter Amelia P. , Rollin Patrick , Tatibouët Arnaud
Published: March 2011

Regio‐ and stereoselective iodinations under controlled Garegg conditions were performed on vicinal diols and contiguous triols located on pyranose templates. β‐D‐Fructo‐ orpsicopyranose‐based diols were selectively iodinated at C‐5 or C‐4, respectively, to afford the L‐sorbo or D‐tagato iodohydrins. In contrast, the related triols only underwent selective iodination at C‐5. Application of the process to D‐gluco‐ and D‐galactopyranosides resulted in selective iodination at C‐3 or C‐4, respectively, to afford the D‐allo or D‐gluco iodohydrins.
An Easy Access to Carbazolones and 2,3‐Disubstituted Indoles
Authors: Janreddy Donala , Kavala Veerababurao , Bosco J. W. John , Kuo Chun‐Wei , Yao Ching‐Fa
Published: March 2011

Synthesis of carbazol‐4‐ones, 3,4‐dihydrocyclopental‐indol‐1‐one, and indole derivatives by a Fe/AcOH‐mediated intramolecular reductive N‐heteroannulation of 3‐hydroxy‐2‐(2‐nitrophenyl)enones is demonstrated. The same protocol has been extended to access indolocarbazolone and indoloquinolone derivatives.
Highly Functionalized, Angularly Anellated Aromatic Compounds from Dendralenes
Authors: Hopf Henning , Yildizhan Şeref
Published: March 2011

[3]Dendralene (2) has been converted into the benz[a]anthracene tetraester13in a protocol involving diene‐transmissive Diels–Alder addition of dimethyl acetylenedicarboxylate to2followed by a sequence of reduction–addition–aromatization reactions. Likewise, the next higher vinylog [4]dendralene (19) provided the phenanthrene hexaester21. An attempt to prepare the doubleo‐xylylene intermediate17failed.
Cyclodextrin Ketones with the Catalytic Group at the Secondary Rim and Their Effectiveness in Enzyme‐Like Epoxidation of Stilbenes
Authors: Fenger Thomas Hauch , Marinescu Lavinia G. , Bols Mikael
Published: March 2011

Several new cyclodextrin ketones with a ketone attached to the secondary face of the cyclodextrin in the form of a 2,3‐O‐(2‐oxopropane‐1,3‐diyl) or 2‐oxo group are reported. These compounds and a selection of known cyclodextrin ketones having the ketone at the primary face were investigated as epoxidation catalysts for oxidation of stilbenes and styrene. A method for determination of kcat in these epoxidations is presented, which was used to determine the rate accelerations for the cyclodextrin ketones relative to background reaction. The highest rate acceleration obtained for epoxidation of 4‐methoxy‐4′‐nitro‐trans‐stilbene was 221. The highest enantioselectivity obtained was 76 % ee of (S)‐styrene oxide.
Determination of salidroside and tyrosol in Rhodiola by capillary electrophoresis with graphene/poly(urea‐formaldehyde) composite modified electrode
Authors: Chen Bo , Zhang Luyan , Chen Gang
Published: March 2011

This report describes the fabrication and application of a novel graphene/poly(urea‐formaldehyde) composite modified electrode as a sensitive amperometric detector of CE. The composite electrode was fabricated on the basis of the in situ polycondensation of a mixture of graphenes and urea–formaldehyde prepolymers on the surface of a platinum disc electrode. It was coupled with CE for the separation and detection of salidroside and tyrosol in Rhodiola, a traditional Chinese medicine, to demonstrate its feasibility and performance. Salidroside and tyrosol have been well separated within 6 min in a 40 cm long capillary at a separation voltage of 12 kV using a 50 mM borate buffer (pH 9.8). The prepared graphene‐based CE detector offered significantly lower detection potential, yielded enhanced signal‐to‐noise characteristics, and exhibited high resistance to surface fouling and enhanced stability. It showed long‐term stability and reproducibility with relative standard deviations of less than 5% for the peak current (n=15).
Some important combinations of detection techniques for electrophoresis in capillaries and on chips with emphasis on electrochemical principles
Authors: Opekar František , Štulík Karel
Published: March 2011

Analyses of very complex samples involving capillary and chip electrophoresis often require dual (multiple) detection to attain sufficient selectivity of determination. The present work reviews and critically evaluates selected combinations of electrochemical detection techniques among themselves and with absorption spectrometric, fluorescence and luminescence techniques. Amperometry, contact and contactless conductometry, UV photometry and fluorescence measurements are paid special attention. Some information is also given on combinations of spectrometric techniques with mass spectrometry. The properties of the detection systems are critically discussed, examples are illustrated in figures and some details on the characteristics of dual detectors and their applications are tabulated.
Imidazolium chloride‐based ionic liquid‐assisted improvement of lipase activity in organic solvents
Authors: Daneshjoo Somayeh , Akbari Neda , Sepahi Abbas Akhavan , Ranjbar Bijan , Khavarinejad Ramezan‐Ali , Khajeh Khosro
Published: March 2011

The activity of a lipase from a newly isolated Pseudomonas sp. was investigated in the presence of organic solvents and imidazolium chloride‐based ionic liquids (IL) such as BMIM[Cl] and HMIM[Cl]. The lipase activity in the presence of IL was higher compared to that in common organic solvents such as methanol and 2‐propanol. A possible explanation for the enzyme activation might be the structural changes induced in the protein in organic systems. Since IL quench the intensity of fluorescence emission, it was not possible to investigate the major factor that influences the enzyme behavior in these new organic salts. Furthermore, the enzyme exhibited excellent activity in buffer mixtures containing both organic solvent and IL. The stability of the lipase at 50°C was considerably increased in the presence of 20% BMIM[Cl] compared with the untreated lipase in aqueous medium. The light scattering method clearly showed that prevention of aggregation could be the reason for thermal stabilization at 50°C in reactions containing IL. Kinetic analysis of the enzyme in the presence of different concentrations of IL showed that the Km value increased from 0.45 mM in aqueous buffer to 2.4 mM in 50% v/v BMIM[Cl]/buffer. The increase in Km indicates that IL can significantly reduce the binding affinity of the substrate to the enzyme. Also, a linear correlation was observed between the BMIM[Cl] concentration and Vmax of the enzyme. As the concentration of BMIM[Cl] increased from 10 to 50% v/v, the Vmax value increased from 1.8 to 46 μM/min.
Cytogenetic biomonitoring on a group of petroleum refinery workers
Authors: Basso Emiliano , Cevoli Chiara , Papacchini Maddalena , Tranfo Giovanna , Mansi Antonella , Testa Antonella
Published: March 2011

Workers employed in petroleum refineries are exposed to a wide range of toxic compounds (benzene, polycyclic aromatic hydrocarbons, heavy metals, etc.) with known mutagenic and carcinogenic potential. In this study, we investigated by using the cytokinesis block micronucleus (CBMN) assay on human peripheral blood lymphocytes (PBL) whether general occupational exposure in petroleum refineries resulted in early biological effects, which would be indicative of adverse health effects in the long term. In this study, out of more 500 workers enrolled in the study, 79 male subjects (46 nonsmokers and 33 smokers), employed in two different Italian petroleum refineries, and a total of 50 male control subjects (34 nonsmokers and 16 smokers) were selected by using very strict selection criteria. The comparison of chromosome damage in PBL between exposed and control populations pointed out a significant increase of micronuclei in the exposed group, correlated with the length of employment. Results confirm that smoking is the principal confounding factor for the responses. In conclusion, our results are indicative of a potential genotoxic risk related to the complex occupational exposure in petroleum refineries, despite the measures adopted in the plants, and corroborate the need to increase safety measures to avoid exposure to chemical agents. Environ. Mol. Mutagen. 2011. © 2011 Wiley‐Liss, Inc.
Accumulation of K‐Rascodon 12 mutations in the F344 rat distal colon following azoxymethane exposure
Authors: McKinzie Page B. , Parsons and Barbara L.
Published: March 2011

Azoxymethane (AOM) administration to F344 male rats is a widely used model of human colon carcinogenesis. The current study investigates quantitatively the accumulation of K‐Rascodon 12 mutations following AOM exposure. Male, 6‐week‐old F344 rats were treated subcutaneously with 30 mg/kg body weight of AOM, and colon tissue was collected at 1, 8, 24, and 32 weeks after treatment. The K‐Rascodon 12 GGT to GAT and GGT to GTT mutant fractions (MFs) were measured using allele‐specific competitive blocker polymerase chain reaction (ACB‐PCR). Between 1 and 32 weeks after AOM treatment, the K‐Rascodon 12 GGT to GAT geometric mean MF in the rat colon increased significantly from 12.9 × 10−5to 145 × 10−5, and the GGT to GTT geometric mean MF increased significantly from 5.26 × 10−5to 180 × 10−5. K‐Rascodon 12 GGT to GAT MF also increased significantly in AOM‐treated rat colon tissue at 1 week compared to controls (4.44 × 10−5). The accumulation of the GGT to GAT MF long after the DNA adduct repair phase suggests that a portion of cells containing this mutation have a proliferative advantage, allowing them to accumulate as nascent tumors progress. Also, the GGT to GAT background MF increased in untreated rats, indicating that there is accumulation with age. The ACB–PCR assay generates quantitative data of cancer‐related mutations and thus provides insight into pathological processes following carcinogen exposure. Environ. Mol. Mutagen., 2011. © Published 2011 Wiley‐Liss, Inc.
Quantitative evaluation of laboratory uptake rates for pesticides, pharmaceuticals, and steroid hormones using POCIS
Authors: Bartelt-Hunt Shannon L , Snow Daniel D , Damon-Powell Teyona , Brown DelShawn L , Prasai Gyanendra , Schwarz Matthew , Kolok Alan S
Published: March 2011

Polar organic chemical integrative samplers (POCIS) are useful in monitoring for a wide range of chemicals in aquatic systems; however, a lack of available uptake rate data for compounds of environmental interest is one limitation in the application of these samplers to environmental studies. In this study, laboratory calibration experiments were conducted with POCIS for 65 compounds at 25°C under flowing conditions to determine chemical-specific uptake rates (Rs). Experimental uptake rates measured in this study ranged from 0.034 to 1.33 L/d, and uptake rates were determined for 36 compounds with no previously reported values. Experimentally determined uptake rates were applied to data obtained from POCIS samplers deployed downstream of three wastewater treatment plant (WWTP) effluent discharges and in four surface waters influenced by agricultural runoff. Time-weighted average concentrations for atrazine and metolachlor determined using uptake rates generated in this study compare well with results from composited grab sampling previously conducted in agricultural watersheds in Nebraska, USA. Environ. Toxicol. Chem. 2011; 30:1412–1420. © 2011 SETAC
Ontogenetic patterns in bluefish (Pomatomus saltatrix) feeding ecology and the effect on mercury biomagnification
Authors: Szczebak Joseph T , Taylor David L
Published: March 2011

In this study, bluefish (Pomatomus saltatrix; age 0–7, n = 632) and their prey (forage fish, macroinvertebrates, zooplankton; n = 2,005) were collected from the Narragansett Bay estuary (RI, USA), and total Hg concentration was measured in white muscle and whole-body tissues, respectively. Bluefish Hg concentrations were analyzed relative to fish length, prey Hg content, and ontogenetic shifts in habitat use and foraging ecology, the latter assessed using stomach content analysis (n = 711) and stable nitrogen (δ15N) and carbon (δ13C) isotope measurements (n = 360). Diet and δ13C analysis showed that age 0 bluefish consumed both benthic and pelagic prey (silversides, sand shrimp, planktonic crustaceans; δ13C = − 16.52‰), whereas age 1 + bluefish fed almost exclusively on pelagic forage fish (Atlantic menhaden, herring; δ13C = − 17.33‰). Bluefish total Hg concentrations were significantly correlated with length (mean Hg = 0.041 and 0.254 ppm wet wt for age 0 and age 1 + bluefish, respectively). Furthermore, Hg biomagnification rates were maximal during bluefish early life stages and decelerated over time, resulting in relatively high Hg concentrations in age 0 fish. Rapid Hg accumulation in age 0 bluefish is attributed to these individuals occupying a comparable trophic level to age 1 + bluefish (δ15N = 15.58 and 16.09‰; trophic level = 3.55 and 3.71 for age 0 and age 1 + bluefish, respectively), as well as juveniles having greater standardized consumption rates of Hg-contaminated prey. Finally, bluefish larger than 30 cm total length consistently had Hg levels above the U.S. Environmental Protection Agency criterion of 0.3 ppm. As such, frequent consumption of bluefish could pose a human health risk, and preferentially consuming smaller bluefish may be an inadequate strategy for minimizing human dietary exposure to Hg. Environ. Toxicol. Chem. 2011; 30:1447–1458. © 2011 SETAC
TICKET-UWM: A coupled kinetic, equilibrium, and transport screening model for metals in lakes
Authors: Farley Kevin J , Carbonaro Richard F , Fanelli Christopher J , Costanzo Robert , Rader Kevin J , Di Toro Dominic M
Published: March 2011

The tableau input coupled kinetic equilibrium transport-unit world model (TICKET-UWM) has been developed as a screening model for assessing potential environmental risks associated with the release of metals into lakes. The model is based on a fully implicit, one-step solution algorithm that allows for simultaneous consideration of dissolved and particulate phase transport; metal complexation to organic matter and inorganic ligands; precipitation of metal hydroxides, carbonates, and sulfides; competitive interactions of metals and major cations with biotic ligands; a simplified description of biogeochemical cycling of organic carbon and sulfur; and dissolution kinetics for metal powders, massives, and other solid forms. Application of TICKET-UWM to a generalized lake in the Sudbury area of the Canadian Shield is presented to demonstrate the overall cycling of metals in lakes and the nonlinear effects of chemical speciation on metal responses. In addition, the model is used to calculate critical loads for metals, with acute toxicity of Daphnia magna as the final endpoint. Model results show that the critical loads for Cu, Ni, Pb, and Zn varied from 2.5 to 39.0 g metal/m2-year and were found to be one or more orders of magnitude higher than comparable loads for pesticides (lindane, 4,4′-DDT) and several polyaromatic hydrocarbon (PAH) compounds. In sensitivity calculations, critical metal-loading rates were found to vary significantly as a function of the hydraulic detention time, water hardness, and metal dissolution kinetic rates. Environ. Toxicol. Chem. 2011; 30:1278–1287. © 2011 SETAC
OFDM channel estimation and data detection with superimposed pilots
Authors: Cui Tao , Tellambura Chintha
Published: March 2011

We propose three iterative superimposed‐pilot based channel estimators for Orthogonal Frequency Division Multiplexing (OFDM) systems. Two are approximate maximum‐likelihood, derived by using a Taylor expansion of the conditional probability density function of the received signal or by approximating the OFDM time signal as Gaussian, and one is minimum‐mean square error. The complexity per iteration of these estimators is given by approximately O(NL2), O(N3) and O(NL), where N is the number of OFDM subcarriers and L is the channel length (time). Two direct (non‐iterative) data detectors are also derived by averaging the log likelihood function over the channel statistics. These detectors require minimising the cost metric in an integer space, and we suggest the use of the sphere decoder for them. The Cramér–Rao bound for superimposed pilot based channel estimation is derived, and this bound is achieved by the proposed estimators. The optimal pilot placement is shown to be the equally spaced distribution of pilots. The bit error rate of the proposed estimators is simulated for N = 32 OFDM system. Our estimators perform fairly close to a separated training scheme, but without any loss of spectral efficiency. Copyright © 2011 John Wiley & Sons, Ltd.
The inflammation hypothesis in geriatric depression
Authors: Alexopoulos George S. , Morimoto Sarah Shizuko
Published: March 2011

Background

A large body of research has focused on “mediating mechanisms” and predisposing brain abnormalities to geriatric depression, but little is known about its etiology. This paper examines whether age‐related and comorbid disease‐related immune deregulation is an etiologic contributor to geriatric depression.

Methods

This article reviews findings on neuroinflammation during the aging process and depression as well as studies of anti‐inflammatory actions of classical antidepressants and antidepressant actions of anti‐inflammatory agents.

Results

Aging results in increased peripheral immune responses, impaired peripheral‐CNS immune communication, and a shift of the CNS into a pro‐inflammatory state. These exaggerated and prolonged immune responses may lead to changes in the function of emotional and cognitive networks pertinent to geriatric depression and to behavioral changes reminiscent of the depressive and cognitive symptoms of geriatric depression. Some antidepressants may reduce the expression of inflammation markers. Limited data suggest that some anti‐inflammatory agents may have antidepressant properties.

Conclusions

A synthesis of available findings suggests that aging‐related and comorbid disease‐related inflammatory processes may promote changes in the neural systems predisposing to geriatric depression or facilitating metabolic changes that mediate depressive syndromes. The “inflammation hypothesis” in geriatric depression cannot be tested in its entirety, but it can lead to testable hypotheses and data on mechanisms by which inflammatory processes promote geriatric depression. The significance of such an effort is that it may lead to a novel treatment development model bringing to bear recent advances of anti‐inflammatory pharmacology to the treatment of depressed elderly patients. Copyright © 2011 John Wiley & Sons, Ltd.
Loneliness and vascular biomarkers: the Dublin Healthy Ageing Study
Authors: O'Luanaigh C. , O'Connell H. , Chin A.V. , Hamilton F. , Coen R. , Walsh C. , Walsh J.B. , Coakley D. , Molloy A. , Scott J. , Cunningham C.J. , Lawlor B.A.
Published: March 2011

Background

Loneliness has been associated with poor physical health and a link has been suggested between the presence of loneliness, cardiovascular health and inflammatory markers.

Objective

To investigate the association between vascular disease biomarkers and loneliness in a community‐dwelling non‐demented elderly population.

Design

cross‐sectional community based assessment.

Participants

466 subjects with mean age 75.45 (SD, 6.06) years. 208 (44.6%) were male.

Results

Higher levels of HbA1c, but not other vascular biomarkers were independently associated with being lonely.

Conclusion

Loneliness was associated with raised levels of HbA1c in a community dwelling elderly population. The mechanism for this association has yet to be elucidated but may reflect an abnormal stress response in people who are lonely. Copyright © 2011 John Wiley & Sons, Ltd.
Growth behavior of cochlear nucleus neuronal cells on semiconductor substrates
Authors: Rak Kristen , Wasielewski Natalia , Radeloff Andreas , Scherzed Agmal , Jablonka Sibylle , Hagen Rudolf , Mlynski Robert
Published: March 2011

Auditory brainstem implants provide sound information by direct stimulation of the cochlear nucleus to patients with dysfunctional or absent cranial nerve VIII. In contrast to patients with cochlear implants, the use of the auditory brainstem implants is less successful. This cannot be fully explained by the difference location of stimulation but a rather unspecific neuronal stimulation. The aim of this study was to further examine neuronal cells of the cochlear nucleus and to test their interactions with semiconductor substrates as a potential electrode material for improved auditory brainstem implants. The cochlear nuclei of postnatal day 7 rats were microsurgically dissected. The tissue was dissociated enzymatically and plated on coverslips as control and on the semiconductor substrates silicon or silicon nitride. After 4 days in culture the morphology and growth of dissociated cells was determined by fluorescence and scanning electron microscopy. Dissociated cells of the cochlear nucleus showed reduced cell growth on semiconductor substrates compared with controls. SEM analysis demonstrated close contact of neurons with supporting cells in culture and good adherence of neuronal growth cones on the used materials. These findings present basic knowledge for the development of neuron–electrode interfaces for future auditory brainstem implants. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Green tea may be benefit to the therapy of atrial fibrillation
Authors: Zeng Xin , Li Qiao , Zhang Miao , Wang Wei , Tan Xuerui
Published: March 2011

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. Systemic inflammatory state, oxidative stress injury, and atrial fibrosis are identified as the main mechanisms for AF. Considering the multifactorial mechanisms of AF, a novel therapeutic agent with multi‐bioactivities should be presented. Regular consumption of green tea has been associated with a reduced risk of coronary heart disease and against a large number of pathologic conditions. Recent results indicate that green tea extract, especially (‐)‐epigallocatechin‐3‐gallate, could effectively decrease inflammatory factors secretion, antagonize oxidation, and inhibit matrix metalloproteinase activities. Inhibition of inflammation, modulation of oxidative stress, and targeting tissue fibrosis represent new approaches in tackling AF; therefore, green tea may be an innovative therapeutic candidate to prevent the occurrence, maintenance, and recurrence of AF. J. Cell. Biochem. 112: 1709–1712, 2011. © 2011 Wiley‐Liss, Inc.
A challenging system: Free energy prediction for factor Xa
Authors: Wallnoefer Hannes G. , Liedl Klaus R. , Fox Thomas
Published: March 2011

Factor Xa (fXa) is a promising target for antithrombotic drugs. Recently, we presented a molecular dynamics study on fXa, which highlighted the need for a careful system setup to obtain stable simulations. Here, we show that these simulations can be used to predict the free energy of binding of several fXa inhibitors. We tested molecular mechanics/Poisson–Boltzmann surface area, molecular mechanics/Generalized Born surface area, and linear interaction energy (LIE) on a small data set of fXa ligands. The continuum solvent approaches only yield satisfying correlations to the experimental results if some of the water molecules are explicitly included in the free energy calculations. LIE gave reasonable results if a sufficiently large data set is used. In general, our procedure of setting up the fXa simulation system enabled MD simulations, which produce adequate ensembles for free energy calculations. © 2011 Wiley Periodicals, Inc. J Comput Chem 2011
Mechanisms of ATP release by human trabecular meshwork cells, the enabling step in purinergic regulation of aqueous humor outflow
Authors: Li Ang , Leung Chi Ting , Peterson‐Yantorno Kim , Stamer W. Daniel , Mitchell Claire H. , Civan Mortimer M.
Published: March 2011

Our guiding hypothesis is that ecto‐enzymatic conversion of extracellular ATP to adenosine activates A1 adenosine receptors, reducing resistance to aqueous humor outflow and intraocular pressure. The initial step in this purinergic regulation is ATP release from outflow‐pathway cells by mechanisms unknown. We measured similar ATP release from human explant‐derived primary trabecular meshwork (TM) cells (HTM) and a human TM cell line (TM5). Responses to 21 inhibitors indicated that pannexin‐1 (PX1) and connexin (Cx) hemichannels and P2X7 receptors (P2RX7) were comparably important in modulating ATP release induced by hypotonic swelling, whereas vesicular release was insignificant. Consistent with prior studies of PX1 activity in certain other cells, ATP release was lowered by the reducing agent dithiothreitol. Overexpressing PX1 in HEK293T cells promoted, while partial knockdown (KD) in both HEK293T and TM5 cells inhibited hypotonicity‐activated ATP release. Additionally, KD reduced the pharmacologically defined contribution of PX1 and enhanced those of Cx and P2RX7. ATP release was also triggered by raising intracellular Ca2+ activity with ionomycin after a prolonged lag time and was unaffected by the PX1 blocker probenecid, but nearly abolished by P2RX7 antagonists. We conclude that swelling‐stimulated ATP release from human TM cells is physiologically mediated by PX1 and Cx hemichannels and P2X7 receptors, but not by vesicular release. PX1 appears not to be stimulated by intracellular Ca2+ in TM cells, but can be modulated by oxidation‐reduction state. The P2RX7‐dependent component of swelling‐activated release may be mediated by PX1 hemichannels or reflect apoptotic magnification of ATP release, either through itself and/or hemichannels. J. Cell. Physiol. 227: 172–182, 2012. © 2011 Wiley Periodicals, Inc.
High‐resolution X‐ray CT for 3D petrography of ferruginous sandstone for an investigation of building stone decay
Authors: Cnudde Veerle , Dewanckele Jan , Boone Matthieu , de Kock Tim , Boone Marijn , Brabant Loes , Dusar Michiel , de Ceukelaire Marleen , de Clercq Hilde , Hayen Roald , Jacobs Patric
Published: March 2011

Diestian ferruginous sandstone has been used as the dominant building stone for monuments in the Hageland, a natural landscape in east‐central Belgium. Like all rocks, this stone type is sensitive to weathering. Case hardening was observed in combination with blackening of the exterior parts of the dressed stones. To determine the 3D petrography and to identify the structural differences between the exterior and interior parts, X‐ray computed tomography was used in combination with more traditional research techniques like optical microscopy and scanning electron microscopy. The 3D characterization of the ferruginous sandstone was performed with a high‐resolution X‐ray CT scanner (www.ugct.ugent.be) in combination with the flexible 3D analysis software Morpho+, which provides the necessary petrophysical parameters of the scanned samples in 3D. Besides providing the required 3D parameters like porosity, pore‐size distribution, grain size, grain orientation, and surface analysis, the results of the 3D analysis can also be visualized, which enables to understand and interpret the analysis results in a straightforward way. The complementarities between high‐quality X‐ray CT images and flexible 3D software and its relation with the more traditional microscopical research techniques are opening up new gateways in the study of weathering processes of natural building stones. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc
Walks and paths in trees
Authors: Bollobás Béla , Tyomkyn Mykhaylo
Published: March 2011

Recently Csikvári [Combinatorica 30(2) 2010, 125–137] proved a conjecture of Nikiforov concerning the number of closed walks on trees. Our aim is to extend this theorem to all walks. In addition, we give a simpler proof of Csikvári's result and answer one of his questions in the negative. Finally we consider an analogous question for paths rather than walks. © 2011 Wiley Periodicals, Inc. J Graph Theory
Convenient synthesis and biological activities of pyridine derivatives of 3,4‐dihydropyrimidin‐2(1H)‐ones
Authors: Zhu Xiao‐Fei , Shi De‐Qing
Published: March 2011

2‐Chloro‐5‐(chloromethyl)‐pyridine reacted with 3,4‐dihydropyrimidin‐2(1H)‐ones 1 to afford 1‐[6‐aryl‐1‐(6‐chloropyridin‐3‐yl‐methyl)‐2‐(6‐chloropyridin‐3‐yl‐methylthio)‐4‐methyl‐1,6‐dihydropyrimidin‐5‐yl] carboxylates or ethanones 2 in good yields. The structure of the target compounds 2 was confirmed by IR, 1H NMR, EI‐MS, and elemental analyses, and compound 2a was further characterized by single crystal X‐ray diffraction. The preliminary bioassay indicated that some of the title compounds possess moderate insecticidal and fungicidal activities. J. Heterocyclic Chem., (2011).
Reaction of cyclic imidates with α,β‐unsaturated esters: Synthesis of new pyrrolo[2,1‐b]‐1,3‐oxazine and pyrido[2,1‐b]‐1,3‐oxazine derivatives
Authors: Ihara Shogo , Soma Takashi , Yano Daigo , Aikawa Shunichi , Yoshida Yasuhiko
Published: March 2011

The cycloaddition reaction of cyclic imidates, 2‐benzyl‐5,6‐dihydro‐4H‐1,3‐oxazines 1a, 1b, 1c, 1d, 1e, 1f, with dimethyl acetylenedicarboxylate 2, trimethyl ethylenetricarboxylate 4, or dimethyl 2‐(methoxymethylene)malonate 6 afforded new fused heterocyclic compounds, such as methyl (6‐oxo‐3,4‐dihydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐ylidene)acetates 3a, 3b, 3c, 3d, 3e, 3f (71–79%), dimethyl 2‐(6‐oxo‐3,4,6,7‐tetrahydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐yl)malonates 5b, 5c, 5d, 5e, 5f (43–71%), or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a, 7b, 7c, 7d, 7e, 7f (32–59%), respectively. In these reactions, 1a, 1b, 1c, 1d, 1e, 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2, 4, and 6 to give annulation products 3, 5, and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem., (2011).
Microwave‐assisted one‐pot synthesis of functionalized pyrimidines using ionic liquid
Authors: Raghuvanshi Dushyant Singh , Singh Krishna Nand
Published: March 2011

An efficient one‐pot multicomponent synthesis of 2,4‐diamino‐5‐pyrimidinecarbonitrile derivatives has been achieved in excellent yields by the condensation of aromatic aldehydes, malononitrile, and guanidine using ionic liquid under controlled microwave irradiation (100 W) at 60°C. This green approach offers a number of advantages in terms of methodology, high‐product yield, short reaction time, mild reaction conditions, and easy workup. J. Heterocyclic Chem., (2011).
The effects of multiple freeze–thaw cycles on the biomechanical properties of the human bone‐patellar tendon‐bone allograft
Authors: Jung Ho‐Joong , Vangipuram Gautum , Fisher Matthew B. , Yang Guoguang , Hsu Shanling , Bianchi John , Ronholdt Chad , Woo Savio L‐Y.
Published: March 2011

Soft tissue allografts, such as the bone‐patellar tendon‐bone (BPTB) graft, have been frequently used for anterior cruciate ligament (ACL) reconstruction. As allografts are subjected to freezing and thawing for multiple cycles, the objective of this study was to measure the changes of the biomechanical properties of the human BPTB allograft after 4 and 8 freeze–thaw cycles in comparison to a single freeze–thaw cycle. Three BPTB specimens were procured from 21 human donors and divided into three groups: 1, 4, or 8 freeze–thaw cycles. Each freeze–thaw cycle consisted of freezing at −20 ± 10°C for more than 6 h and thawing at 22 ± 3°C for at least 6 h. Tensile testing of the BPTB specimens consisted of loading between 50 N and 250 N for 100 cycles and then loading to failure. Cyclic loading revealed a similar amount of creep (∼0.5 mm) among the three freeze–thaw cycles groups (p = 0.38). The stiffness of the BPTB graft for the 1, 4, and 8 freeze–thaw cycle groups were 244 ± 42 N/mm, 235 ± 39 N/mm, and 231 ± 40 N/mm, respectively (p = 0.43). Similar findings were obtained for the ultimate load of the BPTB graft (p = 0.14) and the tangent modulus of the PT substance (p = 0.41). The results of this study suggest that there would be little measurable effect on the structural properties of the BPTB graft or mechanical properties of the PT tissue substance following 8 freeze–thaw cycles. These BPTB allografts could potentially be re‐frozen without a loss in their biomechanical properties, given appropriate storage and care. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1193–1198, 2011
Determination of fluoroquinolones in blood by matrix solid‐phase dispersion extraction and CE
Authors: Li Dan , Yang Qiuling , Wang Ziming , Su Rui , Xu Xu , Zhang Hanqi
Published: March 2011

A simple and rapid method for the determination of residues of four fluoroquinolones in blood samples was developed. The method was based on matrix solid‐phase dispersion extraction followed by CE with ultraviolet detection. 1‐Butyl‐3‐methylimidazolium tetrafluoroborate aqueous solution was used as the background electrolyte for the separation of fluoroquinolones. The average recoveries of the four fluoroquinolones at two spiked levels ranged from 54.0 to 86.4% for pig blood, and 45.4 to 79.9% for deer blood, with the relative standard deviations <9.45%. Detection limits for the four fluoroquinolones in blood sample ranged from 0.15 to 0.31 μg/mL.
Development and validation of two methods based on high‐performance liquid chromatography‐tandem mass spectrometry for determining 1,2‐benzopyrone, dihydrocoumarin, o‐coumaric acid, syringaldehyde and kaurenoic acid in guaco extracts and pharmaceutical preparations
Authors: Gasparetto João C. , Guimarães de Francisco Thais M. , Campos Francinete R. , Pontarolo Roberto
Published: March 2011

In this study, two HPLC‐ESI‐MS/MS methods were developed and validated for the determination of 1,2‐benzopyrone (COU), o‐coumaric acid (OCA), kaurenoic acid (KAU), syringaldehyde (SYR), and dihydrocoumarin (DIH) in guaco extracts and pharmaceutical preparations (syrup and oral solution). The chromatographic separation was achieved using a C18 XBridge 150×2.1‐mm (5‐μm particle size) column maintained at 25°C. The mobile phases consisted of a gradient of water and acetonitrile containing 0.05% formic acid or 5 mM ammonium formate for the positive and negative ion modes, respectively. All of the calibration curves showed excellent coefficients of correlation (r≥0.9970) over the ranges of 1.25–400 ng/mL for coumarin, 10–600 ng/mL for dihydrocoumarin, 5–250 ng/mL for KAU, and 25–500 ng/mL for o‐coumaric acid and syringaldehyde. The range of recovery was 96.3–103% with an RSD% of <4.85% for intraday and interday precision. The results indicate that the developed methods are fast, efficient, and sensitive for the quantification of the guaco metabolites in extracts and pharmaceutical forms while avoiding purification and derivatization steps.
Ultrasound‐assisted extraction of phenolic antioxidants from Acacia confusa flowers and buds
Authors: Tung Yu Tang , Chang Wei Chun , Chen Ping Sheng , Chang Tzu Cheng , Chang Shang Tzen
Published: March 2011

Acacia confusa Merr. (Leguminosae), a species native to Taiwan, is widely distributed on the hills and lowlands of Taiwan, and has been used in traditional medicines. In this study, the application of ultrasound‐assisted extraction was used to extract the phenolic compounds from A. confusa flowers and buds for the first time. Among the extraction methods, it can significantly enhance the contents of phenolic compounds and antioxidant activities in A. confusa flower and bud extracts using ultrasound‐assisted extraction (10 min×12 times). Considering both the solvent consumption and the time needed for extraction, ultrasound‐assisted extraction was found to be the most practical approach for the rapid and efficient extraction of bioactive phenolic constituents. In addition, gallic acid, myricitrin‐3‐rhamnoside, quercitrin‐3‐rhamnoside, europetin‐3‐rhamnoside, kaempferol‐3‐rhamnoside, rhamnetin‐3‐glucoside, and rhamnetin‐3‐rhamnoside were also quantified in different extracts by RP‐HPLC. It is clear that ultrasound‐assisted extraction is an efficient method for extracting phenolic compounds from A. confusa flowers and buds.
Extraction of ketamine from urine using a miniature silica monolithic cartridge followed by quantification with liquid chromatography tandem mass spectrometry (LC‐MS/MS)
Authors: Nema Tarang , Chan Eric C. Y. , Ho Paul C.
Published: March 2011

The high surface area monolith with reactive hydroxyl group on its surface enables it to function as a miniature solid‐phase extraction (SPE) cartridge in size of 1 cm in diameter and 0.5 cm in length. The prepared silica monolith was characterized by Brunauer–Emmett–Teller method, scanning electron microscopy, X‐ray diffraction and Fourier transform infrared (FTIR) spectroscopy. Ketamine was selected as model analyte to validate the extraction efficiency of the prepared cartridge. The extracted ketamine from urine sample was quantitated by liquid chromatography tandem mass spectrometry (LC‐MS/MS) using positive electrospray ionization. The limit of detection and quantification for ketamine was found to be 0.5 and 1.6 ng/mL, respectively. The analysis exhibited linearity in the range of 10–500 ng/mL with coefficient of correlation >0.99. The recovery was found to be in the range of 89–107% with relative standard deviation (RSD) less than 10%. The prepared cartridge was found robust in extracting ketamine efficiently and repeatedly without any significant deterioration in its performance. Moreover, the batch‐to‐batch variations in the performance of the prepared cartridges in terms of % ion suppression of the extracts and recoveries of samples were small, suggesting the consistency in the properties of the monolith.
Determining the efficacy and cost‐effectiveness of the activalve: Results of a long‐term prospective trial
Authors: Graville Donna J. , Palmer Andrew D. , Andersen Peter E. , Cohen James I.
Published: March 2011

Objectives/Hypothesis:

To investigate 1) whether the Provox ActiValve results in increased device‐life in individuals with below average device‐life, 2) whether it is cost‐effective, and 3) whether it has any impact on voice‐related quality of life.

Study Design:

Prospective study.

Methods:

Individuals who experienced below‐average tracheoesophageal prosthesis (TEP) life were studied.

Results:

Individuals with persistent below‐average TEP life were enrolled in the study and underwent periodic re‐evaluation. The majority (73%) experienced significant improvement as a result of use of the device. Those who continued to wear the device were followed for an average of 30.45 months (range, 14.70–43.49 months) and wore a total of 31 devices over this time. They demonstrated an average increase in device‐life of more than 500%, going from an average of 1.93 months with a traditional indwelling device to 10.30 months with the ActiValve. The majority of individuals found that voicing with the ActiValve was either the same or better than with their previous indwelling TEP. Voice‐related quality of life was not significantly different from that of a group of controls. Overall satisfaction with the device was high, and the majority would have chosen the ActiValve in the future. Overall, there were estimated to be cost savings to third‐party payers through use of the ActiValve in this population.

Conclusions:

The ActiValve is effective in increasing device‐life in selected patients who have failed conservative measures. Our protocol for use of the device requires individuals to meet several usage criteria before initial placement and to return for periodic monitoring.
Reticulation de resines epoxydes sous microondes
Authors: Thuillier FrançOise Marie , Jullien Henri , Grenier‐Loustalot Marie‐Florence
Published: March 2011

A microwave treatment has been applied to the curing of a DGEBA epoxy resin with an aromatic diamine (DDS). The aim of study is to understand the energy transfer processes and the crosslinking mechanisms induced by pulsed microwave treatment. The “pulsed” technique induces an increase in the electrical field inside the polymer without changing the overall energy transfer, as compared with continuous microwave treatment of the same average power level. The cured samples were investigated by Fourier Transform Infra‐red, 13C solid state NMR and dynamic mechanical measurements. Network structures were found to be affected by pulse repetition period and peak pulse power.
Etude de la production de resines phenoliques bien definies a partir de precurseurs purs
Authors: Perrin Robert , Lamartine Roger
Published: March 2011

A number of precursors of phenolic resins are prepared, isolated and stabilized. Their properties are studied and particularly their polycondensation reactions that can lead to polymeric materials for composites.
L'influence des thermal spikes sur le comportement d'absorption d'humidite de CFC
Authors: Woehlecke M. , Kuzenko M. V. , Uedelhoven W.
Published: March 2011

For the judgement of mechanical properties of carbon fibre reinforced plastics (CFRP) the knowledge of the moisture absorption behaviour is of essential importance. The influence of constant environmental conditions of CFRP has already been the subject of extensive investigations, but the effects of rapid high temperature excursions (“thermal spikes”) are not yet very well understood. These thermal spikes are encountered on the surface of aircraft components during supersonic flights.

This paper describes a laboratory method for the simulation of thermal spikes. Investigations have been carried out on four different epoxy systems. The influence of thermal spikes with different heating rates on the moisture absorption behaviour of CFRP is reported.
Brain diffusion‐weighted imaging in Friedreich's ataxia
Authors: Rizzo Giovanni , Tonon Caterina , Valentino Maria Lucia , Manners David , Fortuna Filippo , Gellera Cinzia , Pini Antonella , Ghezzo Alessandro , Baruzzi Agostino , Testa Claudia , Malucelli Emil , Barbiroli Bruno , Carelli Valerio , Lodi Raffaele
Published: March 2011

Background:

Friedreich ataxia (FRDA) is the commonest form of autosomal recessive ataxia. This study aimed to define the extent of the brain damage in FRDA patients and to identify in vivo markers of neurodegeneration, using diffusion‐weighted imaging (DWI).

Methods:

We studied 27 FRDA patients and 21 healthy volunteers using a 1.5 T scanner. Axial DW images were obtained and mean diffusivity (MD) maps were generated. Region of interests (ROIs) included medulla, pons, inferior, middle and superior cerebellar peduncles (ICP, SCP, MCP), dentate nucleus, cerebellar white matter, thalamus, caudate, putamen, pallidus, pyramidal tracts at level of posterior limb of internal capsule (PLIC), optic radiations (OR), and corpus callosum. Histograms of MD were generated for all pixels in the whole cerebral hemispheres and infratentorial compartment. Disease severity was assessed by the International Cooperative Ataxia Rating Scale (ICARS).

Results:

FRDA patients had significantly higher MD values than controls in medulla (P < 0.001), ICP (P < 0.001), MCP (P < 0.01), SCP (P < 0.001), OR (P < 0.001), and at the level of the infratentorial structures such as brainstem (P < 0.01), cerebellar hemispheres (P < 0.01), and especially in the cerebellar vermis (P < 0.001). MD values were strongly correlated with disease duration and ICARS score.

Discussion:

Our results showed that DWI is a suitable non‐invasive technique to quantify the extent of neurodegeneration in FRDA, that appears more extended than previously reported, showing a microstructural involvement of structures such as OR and MCP. © 2011 Movement Disorder Society
In vivo evidence for GABAA receptor changes in the sensorimotor system in primary dystonia
Authors: Garibotto Valentina , Romito Luigi M. , Elia Antonio E. , Soliveri Paola , Panzacchi Andrea , Carpinelli Assunta , Tinazzi Michele , Albanese Alberto , Perani Daniela
Published: March 2011

Background:

Preclinical and clinical evidence suggests that impaired gamma‐aminobutyric (GABA) control, leading to disinhibition within the sensorimotor system, might play a role in dystonia. Aim of this study is the in vivo assessment of the GABAergic system in dystonia using positron emission tomography (PET) and 11C‐flumazenil, a selective GABAA receptor ligand.

Methods:

Fourteen subjects with primary dystonia (9 carriers of the DYT1 mutation and 5 sporadic cases) were compared to 11 controls, using a simplified reference tissue model to measure binding potential.

Results:

Voxel‐based analyses showed a reduction in GABAA receptor expression/affinity both in DYT1 carriers and sporadic patients in primary motor and premotor cortex, primary and secondary somatosensory cortex, and in the motor component of the cingulate gyrus.

Conclusions:

Dysfunction of GABAA receptors in sensorimotor systems in primary (genetic and sporadic) dystonia supports the view that lack of GABAergic control may be associated with the generation of dystonic movements. © 2011 Movement Disorder Society
Interpreting the results of Parkinson's disease clinical trials: Time for a change
Authors: Holford Nick H. G. , Nutt John G.
Published: March 2011

Randomized clinical trials testing putative disease‐modifying agents in Parkinson's disease (PD) have yielded controversial results that have not influenced evidence‐based recommendations for the treatment of PD. We argue that the failure of these clinical trials may be linked to end point‐based statistical analyses that must make prior assumptions about the magnitude and the time course of wash‐in and wash‐out of drug effects. Many of these shortcomings may be avoided with quantitative modeling of the entire time course of the clinical trial and examining evidence for three concomitant processes, disease progression, symptomatic drug effects and disease modifying effects. The power of this approach is illustrated by modeling of DATATOP and ELLDOPA trial data. © 2010 Movement Disorder Society
ICAM1 and fibrinogen‐γ are increased in uterine epithelial cells at the time of implantation in rats
Authors: Lecce Laura , Kaneko Yui , Madawala Romanthi J. , Murphy Christopher R.
Published: March 2011

Uterine epithelial cells transform into a receptive state to adhere to an implanting blastocyst. Part of this transformation includes the apical concentration of cell adhesion molecules at the time of implantation. This study, for the first time, investigates the expression of ICAM1 and fibrinogen‐γ (FGG) in uterine epithelial cells during normal pregnancy, pseudopregnancy and in hormone‐treated rats. An increase (P < 0.05) in ICAM1 was seen at the apical membrane of uterine epithelial cells at the time of implantation compared with day 1 of pregnancy. ICAM1 was also increased (P < 0.05) on day 6 of pseudopregnancy as well as in ovariectomized rats treated with progesterone plus oestrogen. These results show that ICAM1 up‐regulation at the time of implantation is under the control of progesterone, and is not dependent on cytokine release from the blastocyst or in semen. FGG dimerization increased (P < 0.05) on day 6 of pregnancy compared with day 1, and was not up‐regulated in day 6 pseudopregnant animals, suggesting this increase is dependent on a developing blastocyst. The presence of ICAM1 and FGG in the uterine epithelium at the time of implantation in the rat is similar to that seen in lymphocyte–endothelium adhesion, and we suggest a similar mechanism in embryo–uterine epithelium adhesion is utilized. Mol. Reprod. Dev. 78:318–327, 2011. © 2011 Wiley‐Liss, Inc.