bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic pathway‐based hierarchical clustering analysis of older adults with cognitive complaints and amnestic mild cognitive impairment using clinical and neuroimaging phenotypes
Authors: Sloan Chantel D. , Shen Li , West John D. , Wishart Heather A. , Flashman Laura A. , Rabin Laura A. , Santulli Robert B. , Guerin Stephen J. , Rhodes C. Harker , Tsongalis Gregory J. , McAllister Thomas W. , Ahles Tim A. , Lee Stephen L. , Moore Jason H. , Saykin Andrew J.
Published: March 2010

Hierarchical clustering is frequently used for grouping results in expression or haplotype analyses. These methods can elucidate patterns between measures that can then be applied to discerning their validity in discriminating between experimental conditions. Here a hierarchical clustering method is used to analyze the results of an imaging genetics study using multiple brain morphology and cognitive testing endpoints for older adults with amnestic mild cognitive impairment (MCI) or cognitive complaints (CC) compared to healthy controls (HC). The single nucleotide polymorphisms (SNPs) are a subset of those included on a larger array that are found in a reported Alzheimer's disease (AD) and neurodegeneration pathway. The results indicate that genetic models within the endpoints cluster together, while there are 4 distinct sets of SNPs that differentiate between the endpoints, with most significant results associated with morphology endpoints rather than cognitive testing of patients' reported symptoms. The genes found in at least one cluster are ABCB1, APBA1, BACE1, BACE2, BCL2, BCL2L1, CASP7, CHAT, CST3, DRD3, DRD5, IL6, LRP1, NAT1, and PSEN2. The greater associations with morphology endpoints suggests that changes in brain structure can be influenced by an individual's genetic background in the absence of dementia and in some cases (Cognitive Complaints group) even without those effects necessarily being detectable on commonly used clinical tests of cognition. The results are consistent with polygenic influences on early neurodegenerative changes and demonstrate the effectiveness of hierarchical clustering in identifying genetic associations among multiple related phenotypic endpoints. © 2010 Wiley‐Liss, Inc.
Characterization of valproic acid‐initiated homologous recombination
Authors: Sha Kevin , Winn Louise M.
Published: March 2010

BACKGROUND: Valproic acid (VPA) is a frequently used antiepileptic agent and known teratogen. Previous research suggests that inhibition of histone deacetylases (HDACs) may play a role in VPA‐induced teratogenicity. We have also shown that VPA exposure leads to both an increase in reactive oxygen species (ROS) production and increased frequency of homologous recombination (HR). METHODS: In the present study, we evaluated the role of HDAC inhibition in VPA‐initiated HR to determine if HDAC inhibition could alter repair activity and/or cause DNA double‐strand breaks (DSBs), which would then initiate repair. Histone acetylation status was assessed to determine if VPA exposure led to HDAC inhibition in CHO 33 cells. RESULTS: Our results demonstrate that VPA (5 mM) exposure leads to increased acetylated histone H3 and H4 protein levels after 10 to 24 hr. Secondly, in our recombination assay where an artificial DNA DSB was induced in CHO 33 cells to assess repair activity, VPA exposure did not affect the repair activity of VPA‐initiated HR. Subsequently, to determine if VPA could increase susceptibility to DNA DSBs, the number of γ‐H2AX foci was assessed using immunocytochemistry and results revealed an increase in γ‐H2AX foci after 10‐ to 24‐hr exposure to VPA. CONCLUSIONS: Although we demonstrated the protective effect of polyethylene glycol‐catalase against VPA‐induced HR and the generation of intracellular ROS within 24 hr, we did not observed an increase in DNA oxidation. These studies suggest that HDAC inhibition and ROS signaling may play roles in DNA maintenance and cell‐cycle arrest in initiating DNA damage and repair. Birth Defects Res (Part B) 89:124–132, 2010. © 2010 Wiley‐Liss, Inc.
Metal–Organic Frameworks with Exceptionally High Methane Uptake: Where and How is Methane Stored?
Authors: Wu Hui , Simmons Jason M. , Liu Yun , Brown Craig M. , Wang Xi‐Sen , Ma Shengqian , Peterson Vanessa K. , Southon Peter D. , Kepert Cameron J. , Zhou Hong‐Cai , Yildirim Taner , Zhou Wei
Published: March 2010

Metal–organic frameworks (MOFs) are a novel family of physisorptive materials that have exhibited great promise for methane storage. So far, a detailed understanding of their methane adsorption mechanism is still scarce. Herein, we report a comprehensive mechanistic study of methane storage in three milestone MOF compounds (HKUST‐1, PCN‐11, and PCN‐14) the CH4 storage capacities of which are among the highest reported so far among all porous materials. The three MOFs consist of the same dicopper paddlewheel secondary building units, but contain different organic linkers, leading to cagelike pores with various sizes and geometries. From neutron powder diffraction experiments and accurate data analysis, assisted by grand canonical Monte Carlo (GCMC) simulations and DFT calculations, we unambiguously revealed the exact locations of the stored methane molecules in these MOF materials. We found that methane uptake takes place primarily at two types of strong adsorption site: 1) the open Cu coordination sites, which exhibit enhanced Coulomb attraction toward methane, and 2) the van der Waals potential pocket sites, in which the total dispersive interactions are enhanced due to the molecule being in contact with multiple “surfaces”. Interestingly, the enhanced van der Waals sites are present exclusively in small cages and at the windows to these cages, whereas large cages with relatively flat pore surfaces bind very little methane. Our results suggest that further, rational development of new MOF compounds for methane storage applications should focus on enriching open metal sites, increasing the volume percentage of accessible small cages and channels, and minimizing the fraction of large pores.
The Impact of Amino Acid Side Chain Mutations in Conformational Design of Peptides and Proteins
Authors: Laufer Burkhardt , Frank Andreas O. , Chatterjee Jayanta , Neubauer Thomas , Mas‐Moruno Carles , Kummerlöwe Grit , Kessler Horst
Published: March 2010

Local energetic effects of amino acid replacements are often considered to have only a moderate influence on the backbone conformation of proteins or peptides. As these effects are difficult to determine experimentally, no comparison has yet been performed. However, knowledge of the influence of side chain mutations is essential in protein homology modeling and in optimizing biologically active peptide ligands in medicinal chemistry. Furthermore, the tool ofN‐methylation of peptides is of increasing importance for the design of peptidic drugs to gain oral availability or receptor selectivity. However,N‐methylation is often accompanied by considerable population ofcis‐peptide bond structures, resulting in completely different conformations compared with the parent peptide. To retain a favored structure, it might be important to understand the effect of different side chains on the backbone conformation and to enable the introduction of anN‐methylation at the right position without disturbing a biologically active conformation. In order to detect even small energetic effects due to side chain mutations, we employed a trick to investigate the structural equilibrium of a selected cyclic pentapeptide in which two conformations are equally populated. Very small energetic differences between both conformations could easily be determined experimentally by identifying shifts in the population of both isomers.
Molecular Dynamics Simulation of Interaction between Calcite Crystal and Phosphonic Acid Molecules
Authors: Zeng Jianping , Zhang Shuguang , Gong Xuedong , Wang Fengyun
Published: March 2010

The interactions between calcite crystal and seven kinds of phosphonic acids, nitrilotris(methylphosphonic acid) (NTMP), nitrilo‐methyl‐bis(methylphosphonic acid) (NMBMP), N,N‐glycine‐bis(methylphosphonic acid) (GBMP), 1‐ hydroxy‐1,1‐ethylenebis(phosphonic acid) (HEBP), 1‐amino‐1,1‐ethylenebis(phosphonic acid) (AEBP), 1,2‐ethylenediamine‐N,N,N′,N′‐tetrakis(methylphosphonic acid) (EDATMP), and 1,6‐hexylenediamine‐N,N,N′,N′‐tetrakis‐ (methylphosphonic acid) (HDATMP) have been simulated by a molecular dynamics method. The results showed that the binding energy of each scale inhibitor with the (1l̄0) (1l̄0) face of calcite crystal was higher than that with (104) face, which has been approved by the analysis of pair correlation functions. The sequence of scale inhibition efficiencies for phosphonic acids against calcite scale is as follows: EDATMP>HDATMP>HEBP>NTMP>GBMP>HEBP>NMBMP, and the growth inhibition on the (1l̄0) face of calcite was at the leading status. Phosphonic acids deformed during the binding process, and electrovalent bonds formed between the phosphoryl oxygen atoms in phosphonic acids and the calcium ions on calcite crystal.
Acoustical Properties of Binary Mixtures of Heptane with Ethyl Acetate or Butyl Acetate
Authors: Shukla Divya , Singh Shashi , Parveen Shahla , Gupta Manisha , Shukla Jagdish Prasad
Published: March 2010

Mixed solvents rather than single pure liquids are of utmost practical importance in chemical and industrial processes as they provide an ample opportunity for the continuous adjustment of desired properties of the medium. Therefore, ultrasonic velocity (u) and density (ρ) were measured for the binary mixtures formed by heptane with ethyl acetate or butyl acetate at temperatures 293, 298 and 303 K over the entire composition range. Deviation in ultrasonic velocity (Δu), deviation in isentropic compressibility (Δκs), and excess intermolecular free length (LEf) have been evaluated using the ultrasonic velocity data and the computed results were fitted to the Redlich‐Kister polynomial equation. The values of Δu, Δκs and LEf were plotted against the molar fraction of heptane. The observed positive and negative values of excess parameters were discussed in terms of molecular interaction between the components of the mixtures. Experimental values of ultrasonic velocity and density were compared with the results obtained by theoretical estimation procedures. The results were discussed in terms of average absolute deviation (AAD).
Syntheses, Structures and Thermal Stabilities of Three Novel Lanthanide Coordination Polymers with 6‐Hydroxynicotinic Acid
Authors: Guo Zhenling , Chen Sanping , Yang Qi , Gao Shengli
Published: March 2010

Three novel lanthanide coordination polymers {[Ce2(HOnic)4(Onic)2(H2O)2]·6H2O}n (1), {[Ln(HOnic)(Onic)‐ (H2O)5·(HOnicH)]·H2O}n [HOnicH=6‐hydroxynicotinic acid, Ln=Nd (2), Pr (3)] have been synthesized and characterized by elemental analyses, IR spectrum and single crystal X‐ray diffraction. Structure analyses reveal that 1 features a 2D plane structure while compounds 2 and 3 possess a 1D chain‐like polymeric structure. TG analyses indicate that 1 exhibits higher thermostability than 2 and 3, which was attributed to the layer polymeric structure of 1.
KHSO4 as an Efficient Catalytic System for the Regiospecific Nitration of Phenols with Metal Nitrates
Authors: Baghernejad Bita , Oskooie Hossein A. , Heravi Majid M. , Beheshtiha Yahia Sh.
Published: March 2010

Highly regiospecific mononitration of phenol and substituted phenols was accomplished employing a metal nitrate and a catalytic amount of KHSO4 in acetonitrile. An exclusive ortho‐selectivity was observed with excellent yields. A variety of metal nitrates were used to obtain o‐nitrophenols exclusively in good to excellent yields. The use of KHSO4 is key for the selectivity observed.
Fast and Efficient Nitration of Salicylic Acid and Some Other Aromatic Compounds over H3PO4/TiO2‐ZrO2 Using Nitric Acid
Authors: Kalbasi Roozbeh Javad , Massah Ahmad Reza , Zamani Farzad , Javaherian Naghash Hamid
Published: March 2010

TiO2‐ZrO2 (1/1)‐surf with Ti and Zr molar ratio of 1/1 was prepared with surfactant through a sol‐gel method. The optimum experimental condition was investigated for nitration of salicylic acid. Then, a number of nitration reactions were carried out with a variety of aromatic compounds in the optimum condition. The 25 wt% H3PO4/TiO2‐ZrO2 (1/1)‐surf catalyst showed good selectivity and yield in a short time for the nitration of salicylic acid and some other aromatic compounds.
A Modified and Green Procedure for the Synthesis of β‐Amido Ketones Using a Br?nsted‐Acidic Ionic Liquid as Novel and Reusable Catalyst
Authors: Davoodnia Abolghasem , Heravi Majid M. , Rezaei‐Daghigh Leila , Tavakoli‐Hoseini Niloofar
Published: March 2010

A green and improved method for the synthesis of β‐amido ketones through one‐pot multi‐component reaction of an enolizable ketone, aryl aldehyde, acetonitrile or benzonitrile in the presence of trimethylsilyl chloride using 3‐methyl‐1‐(4‐sulfonic acid)butylimidazolium hydrogen sulfate [(CH2)4SO3HMIM][HSO4], a Br?nsted‐acidic ionic liquid, as an effective and recyclable catalyst is described. The present methodology offers several advantages such as simple procedure with an easy work‐up, relatively short reaction time, and good to excellent yields.
Highly Efficient and Regio‐selective Glucosylation of 25(S) Ruscogenin by Gliocladium deliquescens NRRL1086
Authors: Chen Naidong , Zhang Jian , Liu Jihua , Yu Boyang
Published: March 2010

A new steroidal glycoside, 25(S) ruscogenin 1‐O‐β‐D‐glucopyranoside (2) was obtained through the microbial transformation of 25(S) ruscogenin (1) by G. deliquescens NRRL1086 in 54% isolated yield. The structure of the product was elucidated by IR, MS and NMR spectra. This is the first report on the preparation of steroidal saponins by microbial transformation.
Ionic Liquid‐coordinated Ytterbium(III) Sulfonate Catalyzed Michael Addition of Indoles to Electron‐deficient Nitroolefins
Authors: Shen Wei , Wang Limin , Tang Jun , Qian Zhenhua , Tong Xiaofeng
Published: March 2010

The Michael addition of indoles to electron‐deficient nitroolefins was effectively catalyzed by an ionic liquid‐coordinated ytterbium(III) sulfonate catalyst. The recycling procedure of the catalyst was very simple without extraction with water, and the catalyst was reused for five times without any loss of its catalytic activity. Furthermore, to demonstrate the application of this methodology, the Pictet‐Spengler reaction was chosen and successfully carried out in the mixture of Br?nsted‐acidic ionic liquid and [bmim]BF4.
Design, Synthesis and Insecticidal Activities of Novel N‐Oxalyl Derivatives of Neonicotinoid Compound
Authors: Zhao Yu , Wang Gang , Li Yongqiang , Wang Suhua , Li Zhengming
Published: March 2010

Ten novel neonicotinoid derivatives containing N‐oxalyl groups were designed and synthesized, and their structures were characterized by 1H NMR, MS, IR, elemental analysis and single crystal X‐ray diffraction analysis. The insecticidal activities of the new compounds were evaluated. The results of bioassays indicated that some of these title compounds exhibited excellent insecticidal activities.
Synthesis of 1,4‐Dihydropyridines Using Ce(SO4)2‐SiO2as Catalyst under Solvent‐free Conditions
Authors: Pei Wen , Wang Qin , Li Xiaonian , Sun Li
Published: March 2010

A facile and efficient one‐pot synthesis of 1,4‐dihydropyridines from aldehyde, 1,3‐dicarbonyl compounds and ammonium acetate in the presence of Ce(SO4)2‐SiO2at 80°C under solvent‐free conditions is described. Compared with the classical Hantzsch reaction, this novel method consistently has the advantages of excellent yields and short reaction time.
Evaluation of the Surface ECG in Detecting Isthmus Conduction Block after Ablation of Typical Atrial Flutter
Authors: Yan Su‐hua , Cheng Wen‐juan , Chen Ming‐you , Xue Mei , Hu He‐sheng
Published: March 2010

Objectives

To investigate the value of changes in P wave morphology and duration detected by surface electrocardiogram (ECG) during proximal coronary sinus (PCS) and low lateral right atrial (LLRA) stimulation as a marker for complete bidirectional isthmus conduction block in the procedure of typical atrial flutter ablation.

Methods

Morphology, duration, and ratio of a positive terminal P wave were estimated in 52 typical atrial flutter patients before and after radiofrequency catheter ablation (RFCA).

Results

Atrial flutter ablation resulted in a complete bidirectional isthmus block in all 52 patients. The terminal portion of the P wave towards a positive morphology was detected in 90.7% (47/52) patients both during PCS and LLRA stimulation. These changes were predominantly observed in the inferior leads. Positive morphological changes of the terminal P wave portion and the measured P wave ratio (40% ± 12%) in the inferior leads indicating bidirectional isthmus conduction block with a sensitivity of 87.5% and a specificity of 91.7% were observed. An increment of 20 ms or more in P wave duration during the PCS stimulation and 10 ms or more during the LLRA stimulation indicating the conduction block with a sensitivity of 90% and a specificity of 100%.

Conclusions

The variation of P wave morphology and duration in inferior leads of the surface ECG is a helpful technique to assess the complete bidirectional isthmus conduction block in the procedure of typical atrial flutter ablation. Copyright © 2010 Wiley Periodicals, Inc.
Early Detection of Left Ventricular Dysfunction with Strain Imaging in Thalassemia Patients
Authors: Bilge Ahmet Kaya , Altinkaya Engin , Ozben Beste , Pekun Figen , Adalet Kamil , Yavuz Selim
Published: March 2010

Background

Iron‐mediated cardiomyopathy is the main cause of death in thalassemia patients. Early detection of cardiac abnormalities is important as aggressive chelation therapy may improve prognosis in these patients. The aim of this study is to evaluate left ventricular (LV) functions by tissue velocity imaging (TVI) and strain imaging (SI) in thalassemia patients without overt heart failure.

Methods

At total of 32 patients with β‐thalassemia major (mean age: 24.2±8.0 y, 22 male) and 25 healthy controls (mean age: 22.8±2.1 y, 20 male) were included. Conventional echocardiography, TVI, and SI were performed on all subjects. Tissue velocity imaging and SI measures included peak systolic, early and late diastolic myocardial velocities, peak systolic strain and strain rate, and early and late diastolic strain rate at the basal segments of the LV lateral and septal walls.

Results

There were no significant differences in LV ejection fraction and fractional shortening between the groups. However, systolic myocardial velocity of the lateral wall and systolic strain and strain rate of the septal and lateral walls were significantly lower in thalassemia patients. There was a significant negative correlation between LV mass index and systolic myocardial velocity of the lateral wall (r = − 0.29, P = .045) and septal systolic strain (r = − 0.45, P < .001).

Conclusion

Thalassemia patients have regional systolic dysfunction in the LV lateral and septal walls, even if they do not have overt heart failure. Strain imaging is helpful in early detection of LV systolic dysfunction in thalassemia patients. Copyright © 2010 Wiley Periodicals, Inc.
Improved synthesis of DOTA tetraamide ligands for lanthanide(III) ions: A tool for increasing the repertoire of potential PARACEST contrast agents for MRI and/or fluorescent sensors
Authors: De León‐Rodríguez Luis M. , Viswanathan Subha , Sherry A. Dean
Published: March 2010

The synthesis of new DOTA tetraamide (DOTAMR4) compounds is of great interest given their application in the formation of Ln(III) complexes as potential PARACEST contrast agents in MRI or fluorescent molecular probes. In this context amino acid and peptide DOTAMR4 derivatives are particularly attractive since the amino‐acid and/or peptide moiety can show responsive properties dependent on a given stimuli which might translate to changes in water exchange rates of the corresponding Ln(III) complex. Current synthesis of DOTAMR4 derivatives is typically carried out by reacting haloacetamide intermediates with cyclen. However, this method fails to generate the tetra‐substituted products when bulky substituents are present in the haloacetamide and in some cases this intermediate cannot be prepared by conventional acylation procedures limiting the number of DOTAMR4 compounds available for study. As a solution to these limitations, an improved methodology for the synthesis of DOTAMR4 by coupling DOTA to an appropriate amine containing reagent (i.e. protected amino‐acids with the α‐amino group free) is presented in this work. Several DOTAMR4 derivatives which are difficult or impossible to prepare with the traditional methodologies were easily obtained starting with DOTA. A new protocol was derived using this methodology for the solution‐phase synthesis of DOTA peptide derivatives. With this methodology, many other DOTAMR4 peptide and non‐peptide derivatives have been prepared in our laboratories with several of these new compounds showing interesting properties for molecular imaging. Copyright © 2010 John Wiley & Sons, Ltd.
Environmental Effects in Computational Spectroscopy: Accuracy and Interpretation
Authors: Pedone Alfonso , Biczysko Malgorzata , Barone Vincenzo
Published: March 2010

Spectroscopic techniques are valuable tools for understanding the structure and dynamics of complex systems, such as biomolecules or nanomaterials. Most of the current research is devoted to the development of new experimental techniques for improving the intrinsic resolution of different spectra. However, the subtle interplay of several different effects acting at different length and time scales still makes the interpretation and analysis of such spectra a very difficult task. In this respect, computational spectroscopy is becoming a needful and versatile tool for the assignment and interpretation of experimental spectra. It is in fact possible nowadays to model with relatively high accuracy the physical–chemical properties of complex molecules in different environments, and to link spectroscopic evidence directly to the structural and dynamical properties of optically or magnetically active solvated probes. In this Review, significant steps toward the simulation of entire spectra in condensed phases are presented together with some basic aspects of computational spectroscopy, which highlight how intramolecular and intermolecular degrees of freedom influence several spectroscopic parameters.
CBr4 as precursor for VPE growth of cubic silicon carbide
Authors: Watts B. E. , Bosi M. , Attolini G. , Battistig G. , Dobos L. , Pécz B.
Published: March 2010

This work presents a study of carbon tetrabromide (CBr4) as precursor to deposit 3C‐SiC on (001) and (111) Si by VPE technique at temperatures ranging between 1000 °C and 1250 °C. TEM, AFM and SEM results indicate that the epitaxy proceeds as a 3D growth of uncoalesced islands at low temperature, whereas a continuous crystalline layer with hillocks on top is obtained above 1200 °C. The hillocks observed at high temperature appear well faceted and their shape and orientation are analyzed in detail by AFM, showing a {311} preferred orientation. 3D island growth was suppressed by adding C3H8 to the precursor gases. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of ZnO nanotubes
Authors: Zhai Hongju , Zheng Jiahong , Yang Jinghai , Liu Yang , Gao Ming
Published: March 2010

Tubular ZnO nanostructures have been obtained via a hydrothermal method at low temperature (90 °C) without any catalysts or templates. The XRD measurement reveals that the tubes are single crystals with hexagonal wurtzite structure. SEM shows that the diameters of ZnO nanotubes ranged from 400 to 550 nm. The Raman and PL spectra indicate that oxygen vacancies or Zn interstitials are responsible for the green emission in the ZnO nanotubes. A possible growth mechanism on the formation of crystalline ZnO nanotubes has been presented. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of the complex perovskite ceramic oxide Ba2YZrO6‐d
Authors: Kumar V. R. , Wariar P. R. S. , Koshy J.
Published: March 2010

Nanocrystalline Ba2YZrO6‐dhas been successfully synthesized through a single step auto‐ignition combustion route. The samples were analyzed by powder X‐ray diffraction, transmission electron microscopy and Ultraviolet‐Visible spectroscopy. The XRD analysis revealed that the material has an ordered complex cubic perovskite structure. The basic optical properties and optical constants of the as‐prepared nanopowder of Ba2YZrO6‐dhave been reported for the first time. The spectral analysis revealed that the material is a wide band gap direct transition semiconductor with band gap of 3.70 eV at room temperature. The poor transmittance in ultraviolet but good transmittance in visible‐near infrared regions make the material potentially important for poultry protection and warming coatings, solar control, antireflection coatings and window layer in solar cells. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of different solvents on the habit of meta‐nitroaniline single crystals
Authors: Srinivasan K. , Kanimozhi S.
Published: March 2010

The habit of the organic non‐linear optical material meta‐nitroaniline (mNA) crystallized from different organic solvents such as acetone, benzene, ethyl acetate, n‐hexane, methanol and toluene were studied. Solubility of mNA in these solvents at various temperatures in the range between 288 and 323 K was determined by gravimetric method. Crystals were grown by restricted evaporation of solvents method. Solutions with different solvents having different chemical nature and polarity yielded crystals with different habits: one‐dimensional needles, two‐dimensional rhombic platelets and three‐dimensional octahedral. In addition, the mNA crystals show unidirectional growth behaviour along its polar [001] direction irrespective of the solvents used. All the grown crystals were found to be orthorhombic system with point group mm2 and space group Pbc21 which was confirmed by powder X‐ray diffraction study. Optical transmittance study showed that the grown mNA single crystals have optical transparency in the wavelength range between 430 and 1550 nm. SHG efficiency of the grown mNA crystal was 3 times grater than KDP. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
caTBUA: Context‐aware ticket‐based binding update authentication protocol for trust‐enabled mobile networks
Authors: You Ilsun , Lee Jong‐Hyouk , Kim Bonam
Published: March 2010

Existing binding update (BU) authentication protocols do not consider context information, such as trust, location, and current time, when verifying a mobile node's care‐of address (CoA). Instead, the correspondent node executes its own CoA validation in spite of facing a highly trusted situation or simply bypasses the CoA validation, making it difficult to maintain a reasonable trade‐off between security and efficiency. This paper applies the context‐aware concept to the BU process and proposes a new context‐aware ticket‐based binding update authentication (caTBUA) protocol. The proposed protocol dynamically performs an appropriate CoA validation based on the context information to achieve a good balance between security and efficiency. Utilizing numerical analysis to compare the performance of the proposed protocol to that of existing authentication protocols in terms of authentication cost and authentication message transmission latency confirmed that the proposed caTBUA protocol yields a better performance than the existing BU authentication protocols. Copyright © 2010 John Wiley & Sons, Ltd.
Site‐Selective Ser‐Hydrolase Labelling with a Luminescent Organometallic NCN–Platinum Complex
Authors: Wieczorek Birgit , Lemcke Bart , Dijkstra Harm P. , Egmond Maarten R. , Klein Gebbink Robertus J. M. , van Koten Gerard
Published: March 2010

The synthesis, spectroscopic properties and protein‐binding studies of a novel luminescent organometallic NCN–platinum complex are described. The luminescent organometallic complex was linked to a serine hydrolase reactive phosphonate group by means of click chemistry, and was exploited in serine hydrolase specific‐binding studies using gel electrophoresis. The NCN–platinum protein label was found to be a robust dye with absorbance and emission maxima between 374–380 and 482–493 nm, respectively, and quantum yields between 0.04 and 0.15.
Self‐Assembled Lanthanide Salicylaldimines with a Unique Coordination Mode
Authors: Kaczmarek Małgorzata T. , Kubicki Maciej , Mondry Anna , Janicki Rafał , Radecka‐Paryzek Wanda
Published: March 2010

New lanthanide salicylaldimine complexes of the formula [Ln(H2L)3(NO3)3](H2L), where Ln = La3+ (1), Nd3+ (2), Eu3+ (3), Gd3+ (4), Ho3+ (5), Er3+ (6), Tb3+ (7) or Yb3+ (8), and H2L = N,N′‐bis(salicylidene)‐4‐methyl‐1,3‐phenylenediamine, were formed in a self‐assembly process involving the lanthanide template‐induced one‐step [2+1] Schiff base condensation reaction between salicylaldehyde and 4‐methyl‐1,3‐phenylenediamine. The unusual coordination pattern of salen‐type ligands in these complexes, in which the three potentially tetradentate N2O2 salicylaldimines function as undeprotonated, monodentate, exclusively O‐donor ligands without involving the nitrogen atoms in the coordination environment, was proved by single‐crystal X‐ray diffraction analysis and correlated with spectroscopic characterization. In this species with the nine‐coordinate distorted tricapped trigonal prism geometry, the nitrates act as bidentate chelators occupying six coordination sites and leaving the remaining sites available for salicylaldimine ligands formed in situ in the template process. The additional salicylaldimine molecule acts as a guest for the salicylaldimine complex host and stabilizes the overall self‐assembled supramolecular network.
Synthesis of a Novel Taxa‐Oxa‐Sugar Hybrid Core Structure by Tandem Cross‐Enyne Metathesis/IMDA
Authors: Nandurdikar Rahul S. , Subrahmanyam Ayyagari V. , Kaliappan Krishna P.
Published: March 2010

This paper describes our design and efforts in synthesizing new scaffolds with taxol‐eleutherobin hybrid core structures and a taxol‐sugar hybrid. The synthesis of taxol‐eleutherobin hybrids involved the synthesis of the A‐ring fragment from carvone and the C‐ring fragment from either D‐mannose or D‐glucose. The Shapiro reaction was used as the key reaction to couple the A‐ and C‐ring fragments of these hybrid structures. Unfortunately, another key reaction (RCM) failed to form the B‐ring and essentially the core unit. However, a tandem enyne cross‐metathesis/intramolecular Diels–Alder strategy was utilized for the synthesis of a taxa‐oxa‐sugar hybrid.
Study on amino amides and enzyme kinetics of L‐asparaginase by MCE
Authors: Qiao Juan , Qi Li , Ma Huimin , Chen Yi , Wang Meixiang , Wang Dexian
Published: March 2010

Seven kinds of amino amides including three synthetic arylglycine amides and four normal amino amides were successfully separated by MCE with LIF detector. Using micellar electrokinetic electrophoresis, the optimized separation of the seven kinds of amino amides was achieved with FITC as the labeling reagent and polyoxyethylene lauryl ether as the surfactant in 20.0 mM borate at pH 9.2. Under the optimized conditions, linearity of L‐asparagine was obtained in the range of 6.6×10−6–2.6×10−4 M; the detection limit (S/N=3) was 0.7 μM. The enzyme kinetic constants of L‐asparaginase using L‐asparagine as substrate were also determined by this method and the kinetic parameter Km and Vmax for the enzymatic hydrolysis of L‐asparagine were 442.0 μM and 69.9 μM/min, respectively.
Investigations on the migration behavior of insulin and related synthetic analogues in CZE, MEKC and MEEKC employing different surfactants
Authors: Haunschmidt Manuela , Ortner Karin , Hainz Katharina , Bradt Elke , Sternbauer Lukas , Buchberger Wolfgang , Klampfl Christian W.
Published: March 2010

The retention/migration behavior of insulin and five synthetic insulin analogues in CZE, MEKC and MEEKC employing seven different detergents within the latter two techniques has been investigated. Substantial changes in separation selectivity in MEKC could be observed for several insulins when moving from SDS to cholate‐based micellar systems. Customized separations could be achieved by using mixtures of SDS and deoxycholate. A similar effect could be observed in MEEKC although the overall quality of MEEKC separations was inferior to those obtained with MEKC.
Liposomes for entrapping local anesthetics: A liposome electrokinetic chromatographic study
Authors: Lokajová Jana , Laine Jaana , Puukilainen Esa , Ritala Mikko , Holopainen Juha M. , Wiedmer Susanne K.
Published: March 2010

Bupivacaine is a lipophilic, long‐acting, amide class local anesthetic commonly used in clinical practice to provide local anesthesia during surgical procedures. Several cases of accidental overdose with cardiac arrest and death have been reported since bupivacaine was introduced to human use. Recent case reports have suggested that Intralipid (Fresenius Kabi) is an effective therapy for cardiac toxicity from high systemic concentrations of, e.g. bupivacaine, even though the mechanism behind the interaction is not fully clear yet. Our long‐term aim is to develop a sensitive, efficient, and non‐harmful lipid‐based formulation to specifically trap harmful substances in vivo. In this study, the in vitro interaction of local anesthetics (bupivacaine, prilocaine, and lidocaine) with Intralipid or lipid vesicles containing phosphatidylglycerol, phosphatidylcholine, cardiolipin, cholesterol, and N‐palmitoyl‐D‐erythro‐sphingosine (ceramide) was determined by liposome electrokinetic chromatography. The interactions were evaluated by calculating the retention factors and distribution constants. Atomic force microscopy measurements were carried out to confirm that the interaction mechanism was solely due to interactions between the analytes and the moving pseudostationary phase and not by interactions with a stationary lipid phase adsorbed to the fused‐silica wall. The heterogeneity of the liposomes was also studied by atomic force microscopy. The liposome electrokinetic chromatography results demonstrate that there is higher interaction between the drugs and negatively charged liposome dispersion than with the commercial Intralipid dispersion.
Determination of glyphosate and its metabolites in plant material by reversed‐polarity CE with indirect absorptiometric detection
Authors: Rojano‐Delgado Antonia María , Ruiz‐Jiménez José , de Castro María Dolores Luque , De Prado Rafael
Published: March 2010

A simple CE method for simultaneous determination of glyphosate and its metabolites (i.e. aminomethylphosphonic acid, glyoxylate, sarcosine and formaldehyde) in plants is reported here. A BGE of pH 7.5, 10% ACN, 7.5 mM phthalate, containing 0.75 mM hexadecyltrimethylammonium bromide as an electro‐osmotic flow modifier, an applied voltage of –20 kV and absorptiometric monitoring at 220 nm were the optimal chemical and instrumental parameters. The method, with development time 20 min, shows linear calibrations within the range 5–500 μg/mL (for all target analytes) with correlation coefficients between 0.999 and 0.998. It has been validated by application to samples of Lolium spp. The electroinjection mode hinders most interferents to enter the capillary, thus providing a clean electropherogram and making unnecessary long sample‐preparation steps.
Enantioselective CE analysis of hepatic ketamine metabolism in different speciesin vitro
Authors: Schmitz Andrea , Thormann Wolfgang , Moessner Lone , Theurillat Regula , Helmja Kati , Mevissen Meike
Published: March 2010

Ketamine, an injectable anesthetic and analgesic consisting of a racemic mixture ofS‐andR‐ketamine, is routinely used in veterinary and human medicine. Nevertheless, metabolism and pharmacokinetics of ketamine have not been characterized sufficiently in most animal species. An enantioselective CE assay for ketamine and its metabolites in microsomal preparations is described. Racemic ketamine was incubated with pooled microsomes from humans, horses and dogs over a 3 h time interval with frequent sample collection. CE data revealed that ketamine is metabolized enantioselectively to norketamine (NK), dehydronorketamine and three hydroxylated NK metabolites in all three species. The metabolic patterns formed differ in production rates of the metabolites and in stereoselectivity of the hydroxylated NK metabolites.In vitropharmacokinetics of ketamineN‐demethylation were established by incubating ten different concentrations of racemic ketamine and the single enantiomers of ketamine for 8 min and data modeling was based on Michaelis–Menten kinetics. These data revealed a reduced intrinsic clearance of theS‐enantiomer in the racemic mixture compared with the singleS‐enantiomer in human microsomes, no difference in equine microsomes and the opposite effect in canine microsomes. The findings indicate species differences with possible relevance for the use of singleS‐ketamineversusracemic ketamine in the clinic.
Impact of land use on the hydraulic properties of the topsoil in a small French catchment
Authors: Gonzalez‐Sosa E. , Braud I. , Dehotin J. , Lassabatère L. , Angulo‐Jaramillo R. , Lagouy M. , Branger F. , Jacqueminet C. , Kermadi S. , Michel K.
Published: March 2010

The hydraulic properties of the topsoil control the partition of rainfall into infiltration and runoff at the soil surface. They must be characterized for distributed hydrological modelling. This study presents the results of a field campaign documenting topsoil hydraulic properties in a small French suburban catchment (7 km2) located near Lyon, France. Two types of infiltration tests were performed: single ring infiltration tests under positive head and tension‐disk infiltration using a mini‐disk. Both categories were processed using the BEST—Beerkan Estimation of Soil Transfer parameters—method to derive parameters describing the retention and hydraulic conductivity curves. Dry bulk density and particle size data were also sampled. Almost all the topsoils were found to belong to the sandy loam soil class. No significant differences in hydraulic properties were found in terms of pedologic units, but the results showed a high impact of land use on these properties. The lowest dry bulk density values were obtained in forested soils with the highest organic matter content. Permanent pasture soils showed intermediate values, whereas the highest values were encountered in cultivated lands. For saturated hydraulic conductivity, the highest values were found in broad‐leaved forests and small woods. The complementary use of tension‐disk and positive head infiltration tests highlighted a sharp increase of hydraulic conductivity between near saturation and saturated conditions, attributed to macroporosity effect. The ratio of median saturated hydraulic conductivity to median hydraulic conductivity at a pressure of − 20 mm of water was about 50. The study suggests that soil texture, such as used in most pedo‐transfer functions, might not be sufficient to properly map the variability of soil hydraulic properties. Land use information should be considered in the parameterizations of topsoil within hydrological models to better represent in situ conditions, as illustrated in the paper. Copyright © 2010 John Wiley & Sons, Ltd.
New diagnostic estimates of variations in terrestrial water storage based on ERA‐Interim data
Authors: Mueller Brigitte , Hirschi Martin , Seneviratne Sonia I.
Published: March 2010

Terrestrial water storage is an important component of the climate system as it determines the partitioning of the water and energy fluxes at the land surface. Since in situ measurements are scarce, there is a strong need for alternative validation data sources.

Here we present a new dataset of monthly basin‐scale terrestrial water storage changes (TWSC) derived with the combined atmospheric‐terrestrial water‐balance approach, also referred to as basin‐scale water‐balance (BSWB) approach. It is diagnosed from observation‐constrained reanalysis data for the atmospheric fields and observed streamflow. A previous BSWB dataset derived from the European Center for Medium‐Range Weather Forecasts (ECMWF) reanalysis ERA‐40 provided reasonable estimates of TWSC for mid‐latitude basins. The here presented BSWB dataset is derived from the latest ECMWF reanalysis ERA‐Interim, which is available in real time. The potential real‐time availability of TWSC derived from ERA‐Interim is of great relevance for several agricultural, hydrological, and climate applications.

An uncertainty analysis of the derived TWSC highlights the importance of the atmospheric moisture flux convergence fields from the reanalysis for the resulting product uncertainty. We find that the BSWB estimates have a relative uncertainty of about 4–6% in basins larger than 1·5 × 106 km2 compared with the mean seasonal cycle. The ERA‐Interim based dataset compares better with in situ soil moisture, snow depth, and groundwater measurements in the Ob basin and Illinois than the previous ERA‐40 based dataset. We further compare the BSWB datasets to retrievals from the Gravity Recovery And Climate Experiment (GRACE), scatterometer data from the European Remote Sensing (ERS) satellites, and land surface model output from the second phase of the Global Soil Wetness Project (GSWP). We find a better correlation between ERS and the BSWB data than between GRACE and the BSWB data, which might be related to the relatively coarse resolution of GRACE. GSWP model output and the BSWB datasets compare well in most of the studied river basins. Copyright © 2010 John Wiley & Sons, Ltd.
Biochemical comparisons of osteoarthritic human synovial fluid with calf sera used in knee simulator wear testing
Authors: Brandt J.‐M. , Brière L. K. , Marr J. , MacDonald S. J. , Bourne R. B. , Medley J. B.
Published: March 2010

Osteoarthritic human synovial fluid was obtained from the knees of 20 patients and was compared with four different calf sera solutions frequently used as lubricants in knee simulator wear testing. Assuming that the fluid after arthroplasty was the same as the fluid in patients with osteoarthritis, the total protein concentration, protein constituent fractions, osmolality, trace element concentrations, and the thermal stability obtained via differential scanning calorimetry were determined. Human synovial fluid, with an average total protein concentration of 34 g/L, was significantly different from all undiluted calf sera. However, alpha‐calf serum and iron‐supplemented alpha‐calf serum were closest in protein constituent fractions (albumin, α‐1‐globulin, α‐2‐globulin, ß‐globulin, and γ‐globulin) to human synovial fluid. Diluting calf sera with low‐ion distilled water to a total protein concentration of 17 g/L (as recommended by ISO 14243) produced non‐clinically relevant total protein concentration and osmolality levels. Performing the same dilution of iron‐supplemented alpha‐calf serum with phosphate‐buffered saline solution and 1.5 g/L hyaluronic acid produced an artificial lubricant with both a clinically relevant level of osmolality and clinically relevant thermal stability as seen in human synovial fluid from patients with osteoarthritis. The present study suggested that alpha‐calf serum, phosphate‐buffered saline solution and hyaluronic acid were essential constituents of an artificial lubricant to mimic the major biochemical properties of human synovial fluid for simulator wear testing of total knee replacements. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Tissue response to the components of a hydroxyapatite‐coated composite femoral implant
Authors: Hacking S. A. , Pauyo T. , Lim L. , Legoux J. G. , Bureau M. N.
Published: March 2010

Bone loss around femoral implants used for THA is a persistent clinical concern. It may be caused by stress shielding, generally attributed to a mismatch in stiffness between the implants and host bone. In this regard, a fatigue resistant, carbon fiber (CF) composite femoral implant with bone‐matching stiffness has been developed. This study evaluated the tissue response to the three material components of this implant in normal and textured (blasted with 24 grit alumina) surfaces: the hydroxyapatite (HA) coating, the CF composite and the intermediate crystalline HA particulate composite layer to bond to the HA coating (blended). Sprague‐Dawley rats underwent bilateral femoral implantation each receiving two rod‐like implants. Bone apposition to the HA (37%) and textured Ti (41%) implants was not significantly different. Bone apposition to the untextured CF (14%) and blended (19%) implants and polished Ti (8%) implants was significantly lower. Bone apposition to the textured CF (9%) and blended (11%) implants was lower (but not statistically from the as received or untextured counterparts). Nearly all sections from femurs containing CF implants presented CF debris. There was no evidence of localized bone loss or any strong immune response associated with any of the implant materials. All materials were well tolerated with minimal inflammation despite the presence of particulate debris. The high degree of bone apposition to the HA‐coated composite implants and the lack of short‐term inflammation and adverse tissue response to the three material implant component support continued evaluation of this composite technology for use in THA. Published 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
The influence of proteins on demineralization kinetics of hydroxyapatite aggregates
Authors: Kosoric Jelena , Hector Mark P. , Anderson Paul
Published: March 2010

Salivary proteins influence the biomineralization of hydroxyapatite (HAp) within enamel. Their effect on the crystal growth has been extensively studied, but, their effect on demineralization kinetics is less well investigated. In this study bovine serum albumin (BSA) was used as a model protein to measure its effect on demineralization kinetics of hydroxyapatite aggregates using scanning microradiography (SMR). HAp aggregates (8 and 20% porous) were cut into 5 × 5 × 2 mm blocks. SMR cells were prepared containing hydroxyapatite blocks. BSA was added to demineralising solutions (0.1 mol L−1 acetic acid, buffered to pH 4.0; degree of saturation zero and 0.062 respectively) at a concentration range 0.76–75.8 μmol L−1. Demineralising solution without added BSA was used as a control. The demineralising solutions were circulated past the samples at 0.4 mL min−1. SMR was used to measure the rate of mineral loss (RMLHAp) at 14 points in each sample repeatedly for 3 weeks. The results show that BSA increases or decreases the RMLHAp depending on; BSA concentration, HAp porosity, and the degree of saturation of the demineralising solution. It is suggested that BSA influences demineralization kinetics of HAp either by modifying solution properties, or, by affecting the surface energy of hydroxyapatite. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010