bluuebunny/crossref_metadata_2025 huggingface dataset:
Stereoselective determination of the epimer mixtures of itraconazole in human blood plasma using HPLC and fluorescence detection
Authors: Pyrgaki Christina , Bannister Steve J. , Gera Lajos , Gerber John G. , Gal Joseph
Published: June 2011

Itraconazole is an antifungal drug widely used in a variety of fungal infections, which have become a significant public‐health problem in recent decades. Itraconazole is a chiral drug consisting of two diastereoisomeric racemates, i.e., four stereoisomers. Data in the literature suggests that stereochemistry may play a significant role in the action and disposition of the drug and therefore stereoselective analytical methods for the determination of the drug in biological fluids are needed for the elucidation of that role. We report a stereoselective HPLC method that incorporates solvent extraction, the use of an internal standard, two chiral stationary phases in series, and fluorescence detection. The procedure is enantioselective and partially diastereoselective and provides the concentrations in blood plasma of the two epimer mixtures 2R,4S,2'R/2R,4S2'S and 2S,4R,2'R/2S,4R,2'S, respectively, each of which is a combination of the two epimers that differ in the configuration at the sec‐butyl group. The analytical method has suitable sensitivity, recovery, precision, and accuracy. Analysis of the plasma of a human subject six hours after the oral administration of a single 200‐mg dose of itraconazole showed a 3.4‐fold difference between the concentrations of the epimer mixtures. The method has certain advantages over the published alternative procedure that uses LC‐MS. Chirality 2011. © 2011 Wiley‐Liss, Inc.
Kupfer
Authors: Schwedt Georg
Published: June 2011

Das seit fast 200 Jahren bestehende Mineralogische Museum der Universität Bonn, das 1874 eine bedeutende Sammlung vom Gründer des heutigen Rheinischen Mineralien‐Kontors A. Krantz erhielt, zeigt unter anderem systematisch geordnet Minerale zu ausgewählten chemischen Elementen. Sie werden in dieser Serie zum Internationalen Jahr der Chemie 2011 näher vorgestellt.
Oxime‐Based Click Chemistry in the Development of 3‐Isoxazolecarboxylic Acid Containing Inhibitors of Yersinia pestis Protein Tyrosine Phosphatase, YopH
Authors: Bahta Medhanit , Burke Terrence R.
Published: June 2011

The pathogenicity of Yersinia pestis relies on several effector proteins including YopH, a protein tyrosine phosphatase (PTP). We previously screened a library of analogues based on the ubiquitous PTP substrate para‐nitrophenylphosphate (pNPP) and found that incorporation of a 3‐phenyl substituent to give 6‐nitro‐[1,1′‐biphenyl]‐3‐yldihydrogen phosphate (1) enhanced affinity. Herein we report the conversion of 1 from a substrate into an inhibitor by replacing the hydrolysable phosphoryl group with a 3‐isoxazolecarboxylic acid moiety and by introduction of an aminooxy group and subsequent diversification using oxime‐based click chemistry. This approach led to the identification of non‐promiscuous bidentate YopH inhibitors with affinity in the low micromolar range.
Evaluation of a scoring system for predicting lymph node malignancy in ultrasound guided fine needle aspiration practice
Authors: Wu Maoxin , Chen Hua , Zheng XiaoYong , Burstein David E. , Aisner Dara
Published: June 2011

Ultrasound‐guided fine needle aspiration (USG‐FNA) has enabled cytopathologists to accurately diagnose smaller or non‐palpable lymph nodes (LN) on a regular basis. Pre‐FNA clinical and ultrasonographic factors, such as a patient's age, ratio of short to long axis diameter (S/L ratio), internal echogenicity, and the vascular pattern of a LN, are reported to be able to predict the benign or malignant nature of a LN. This study is designed to test the formula “0.06 × (age) + 4.76 × (S/L ratio) + 2.15 × (internal echo) + 1.80 × (vascular pattern)” generated from the study of Liao et al. as a scoring system for predicting LN malignancy in a cytopathologist operated USG‐FNA practice.

Eighty‐three reports of USG‐FNA of LNs issued between 7/1/2008 and 4/28/2010 were reviewed. Patient's age, S/L ratio, internal echo, and vascular pattern were used to generate scores based on the aforementioned formula. A score of seven was used as a cutoff for predicting benign (<7) and malignant (>7) LNs. FNA cytology diagnosis, flow cytometric analysis as well as subsequent surgical diagnosis in some cases served as gold standard for statistical analysis.

Among 46 USG‐FNA of LNs with scores > 7, 38 were malignant and eight were benign. All 37 USG‐FNA of LNs with scores < 7 were proven to be benign. The scoring system achieved 100% sensitivity, 82% specificity, 83% positive predictive value, 100% negative predictive value, and 90% accuracy. Further study of the eight “false‐positive” cases revealed that three of them (37.5%) were found to be malignant in follow‐up FNA and/or surgical biopsy.

This scoring system may serve as a complementary tool in determining how aggressive a FNA procedure should be performed, how a FNA sample of LN should be triaged for ancillary study, and how closely a patient with lymphadenopathy should be followed up. Diagn. Cytopathol. 2013;41:1100–1106. © 2011 Wiley Periodicals, Inc.
Division of labor between subsets of lymph node dendritic cells determines the specificity of the CD8+ T‐cell recall response to influenza infection
Authors: Suárez‐Ramírez Jenny E. , Wu Tao , Lee Young‐Tae , Aguila Carolina C. , Bouchard Keith R. , Cauley Linda S.
Published: June 2011

Cytotoxic T lymphocytes (CTLs) are important targets for vaccines against a wide variety of infections that enter the body via mucosal tissues. To induce effective immunity these vaccines must include the most protective epitopes and elicit rapid recall responses at the site of infection. Although live attenuated viruses are sometimes used to induce cellular immunity against recurrent influenza infections, the mechanisms that determine the magnitude of the response to individual viral components are very poorly defined. Heterosubtypic infections in C57BL/6 mice illustrate an additional level of complexity, when the antigen specificity of the response shifts dramatically between primary and secondary challenge. This model provides a unique opportunity to identify the mechanisms that regulate memory CD8+ T‐cell reactivation in vivo and control the specificity of the recall response by pathogen‐specific CTL. We show that multiple factors contribute to the changing pattern of immunodominance during secondary infection, including the location of the memory CD8+ T cells at the time of reinfection and their ability to directly recognize migratory CD103+ DCs as they arrive in the lung draining LN.
Novel Quinidine‐Derived Organocatalysts for the Asymmetric Substitutions of O‐Boc‐Protected Morita–Baylis–Hillman Adducts
Authors: Pei Cheng‐Kui , Zhang Xiu‐Chun , Shi Min
Published: June 2011

A series of novel quinidine‐derived organocatalysts was synthesized and utilized for the asymmetric substitution of O‐Boc‐protected Morita–Baylis–Hillman adducts with various carbamates and tosylcarbamates, affording the corresponding products in good to high yields (up to 91 % yield) with moderate to high ee values (up to 96 % ee) under mild conditions.
A novel approach to the electrical safety of low‐voltage installations: the TN‐Island grounding system
Authors: Parise Giuseppe , Mitolo Massimo
Published: June 2011

TN‐Island grounding system is an effective way to both protect persons from shock hazard in installations with limited demand load and greatly limit electrical interferences among systems. This distribution system, which utilizes separation transformers, grounded on the secondary sides, allows one to supply loads broken into “islands” as independent electrical areas. TN‐Island fits best the supply of electrical installations in particular locations like moored pleasure crafts in marinas, fish farms, fish tanks, refrigerated containers in seaports, data centers, and construction sites. Additionally, by introducing the TN‐Island to provide power to dwelling units, regardless of their existing electrical distribution system, we can improve electrical safety and, at the same time, increase reliability since the “islands” are not electrically interfering with each other. Last but not least, the TN‐Island system, allows one to develop “hybrid” systems just for restricted electrical areas, for example, dwelling units, and can lead to a free choice of systems and standards (i.e., NEC‐USA and IEC‐UE). This would eliminate technical obstacles and discourage market barriers. Such a process is as crucial as it is inevitable, as a consequence of the current world globalization. This could promote electrical safety, better functionality, and lower costs. Copyright © 2011 John Wiley & Sons, Ltd.
A high order spectral volume solution to the Burgers' equation using the Hopf–Cole transformation
Authors: Kannan Ravi , Wang Z.J.
Published: June 2011

A limiter free high order spectral volume (SV) formulation is proposed in this paper to solve the Burgers' equation. This approach uses the Hopf–Cole transformation, which maps the Burgers' equation to a linear diffusion equation. This diffusion equation is solved in an SV setting. The local discontinuous Galerkin (LDG) and the LDG2 viscous flux discretization methods were employed. An inverse transformation was used to obtain the numerical solution to the Burgers' equation. This procedure has two advantages: (i) the shock can be captured, without the use of a limiter; and (ii) the effects of SV partitioning becomes almost redundant as the transformed equation is not hyperbolic. Numerical studies were performed to verify. These studies also demonstrated (i) high order accuracy of the scheme even for very low viscosity; (ii) superiority of the LDG2 scheme, when compared with the LDG scheme. In general, the numerical results are very promising and indicate that this procedure can be applied for obtaining high order numerical solutions to other nonlinear partial differential equations (for instance, the Korteweg–de Vries equations) which generate discontinuous solutions. Copyright © 2011 John Wiley & Sons, Ltd.
Alumina–Carbon Nanofibers Nanocomposites Obtained by Spark Plasma Sintering for Proton Exchange Membrane Fuel Cell Bipolar Plates
Authors: Borrell A. , Torrecillas R. , Rocha V. G. , Fernández A.
Published: June 2011

There is an increasing demand of multifunctional materials for a wide variety of technological developments. Bipolar plates for proton exchange membrane fuel cells are an example of complex functionality components that must show among other properties high mechanical strength, electrical, and thermal conductivity. The present research explored the possibility of using alumina–carbon nanofibers (CNFs) nanocomposites for this purpose. In this study, it was studied for the first time the whole range of powder compositions in this system. Homogeneous powders mixtures were prepared and subsequently sintered by spark plasma sintering. The materials obtained were thoroughly characterized and compared in terms of properties required to be used as bipolar plates. The control on material microstructure and composition allows designing materials where mechanical or electrical performances are enhanced. A 50/50 vol.% alumina–CNFs composite appears to be a very promising material for this kind of application.
The caranto paleosol and its role in the early urbanization of Venice
Authors: Donnici Sandra , Serandrei‐Barbero Rossana , Bini Claudio , Bonardi Maurizio , Lezziero Alberto
Published: June 2011

As rising sea level threatens Venice, there is a need to construct a historical framework for interpreting modern environmental changes. Environmental conditions that would later help support Venice's urbanization were established during the Late Glacial period when calcic soils began to develop in the Venetian alluvial paleoplain. A calcic paleosol, buried by Middle to Late Holocene marine transgressive deposits, represents a subsurface layer long known in the Venice area as “caranto.” Referenced in the ancient chronicles of architects and builders, the caranto exhibits relatively high compressive and shear strength, making it an important substrate for supporting building foundations, some dating back to the Gothic era (12th–15th centuries A.D.). Hence, the caranto paleosol documents local post‐glacial environmental changes while playing an important role in Venetian building construction and human settlement. Here we provide geochemical, sedimentological, paleoecological, and chronological analyses of the caranto paleosol and related deposits based on recent coring of the Venetian Lagoon. © 2011 Wiley Periodicals, Inc.
Mesenchymal stem cell seeding promotes reendothelialization of the endovascular stent
Authors: Wu Xue , Wang Guixue , Tang Chaojun , Zhang Dechuan , Li Zhenggong , Du Dingyuan , Zhang Zhengcai
Published: June 2011

This study is designed to make a novel cell seeding stent and to evaluate reendothelialization and anti‐restenosis after the stent implantation. In comparison with cell seeding stents utilized in previous studies, Mesenchymal stem cells (MSCs) have advantages on promoting of issue repair. Thus it was employed to improve the reendothelialization effects of endovascular stent in present work. MSCs were isolated by density gradient centrifugation and determined as CD29+CD44+CD34− cells by immunofluorescence and immunocytochemistry; gluten and polylysine coated stents were prepared by ultrasonic atomization spray, and MSCs seeded stents were made through rotation culture according to the optimized conditions that were determined in previous studies. The results from animal experiments, in which male New Zealand white rabbits were used, show that the reendothelialization of MSCs coated stents can be completed within one month; in comparison with 316L stainless steel stents (316L SS stents) and gluten and polylysine coated stents, the intimal hyperplasia and in‐stent restenosis are significantly inhibited by MSCs coated stents. Endovascular stent seeded with MSCs promotes reendothelialization and inhibits the intimal hyperplasia and in‐stent restenosis compared with the 316L SS stents and the gluten and polylysine coated stents. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: , 2011.
A novel dermal substitute based on biofunctionalized electrospun PCL nanofibrous matrix
Authors: Gümüşderelioğlu Menemşe , Dalkıranoğlu Sevcan , Aydın R. Seda Tığlı , Çakmak Soner
Published: June 2011

In this study, nanofibrous matrices of polycaprolactone (PCL) and PCL/collagen with immobilized epidermal growth factor (EGF) were successfully fabricated by electrospinning for the purpose of damaged skin regeneration. Nanofiber diameters were found to be 284 ± 48 nm for PCL and 330 ± 104 nm for PCL/collagen matrices. The porosities were calculated as 85% for PCL and 90% for PCL/collagen matrices. The covalent immobilization of EGF onto the nanofibrous matrices was verified by the increase of surface atomic nitrogen ratio from 1.0 to 2.4% for PCL and from 3.7 to 4.7% for PCL/collagen. Moreover, EGF immobilization efficiencies of PCL and PCL/collagen matrices were determined as 98.5 and 99.2%, respectively. Human dermal keratinocytes (HS2) were cultivated on both neat and EGF immobilized PCL and PCL/collagen matrices to investigate the effects of matrix chemical composition and presence of EGF on cell proliferation and differentiation. EGF immobilized PCL/collagen matrices exerted early cell spreading and rapid proliferation. Statistically high expression levels of loricrin in HS2 cells cultivated on EGF immobilized PCL/collagen matrices were (p < 0.001) regarding superior differentiation ability of these cells compared to HS2 cells cultured on neat PCL and PCL/collagen matrices. In conclusion, this novel EGF immobilized PCL/collagen nanofibrous matrix could potentially be considered as an alternative dermal substitutes and wound healing material for skin tissue engineering applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Nonideality in diffusion of ionic and neutral solutes and hydrogen bond dynamics in dimethyl sulfoxide–chloroform mixtures of varying composition
Authors: Gupta Rini , Chandra Amalendu
Published: June 2011

Molecular dynamics simulations of charged and neutral solutes in dimethyl sulfoxide (DMSO)–chloroform mixtures reveal pronounced nonideality in the solute diffusion with changes of composition of the mixtures. The diffusion coefficient of the anionic solute first decreases, passes through a minimum at DMSO mole fraction of about 0.50, and then increases to reach its value for pure DMSO. The diffusion coefficients of the cationic and neutral solutes are found to decrease with increase in DMSO content of the solvent mixture. The extent of nonideality in the diffusion and orientational relaxation of solvent molecules is found to be somewhat stronger than that in diffusion of the anionic solute in these mixtures. We have also calculated the relaxation of hydrogen bonds formed between DMSO and chloroform molecules. The lifetimes of DMSO–chloroform hydrogen bonds are found to increase monotonically with increase in DMSO concentration. The average number of hydrogen bonds and their average energies are also computed. It is found that an increase in DMSO concentration causes a decrease in the number of DMSO–chloroform hydrogen bonds per DMSO or chloroform molecules but increases the strength of these hydrogen bonds. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
A computational study of unique properties of pillar[n]quinones: Self‐assembly to tubular structures and potential applications as electron acceptors and anion recognizers
Authors: Lao Ka‐un , Yu Chin‐hui
Published: June 2011

Density functional theory has been used to calculate the thermodynamic properties and molecular orbitals of pillar[n]quinones. Pillar[n]quinones are expected to be effective electron acceptors and the ability to accept more than one electron increases with the size of the interior cavity. Pillar[5]quinone and pillar[7]quinone show a great intramolecular charge transfer upon the electron excitation from highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) as indicated by a large difference of electron distributions between their HOMO and LUMO and a notable dipole moment difference between the ground and first triplet excited state. The aggregation of pillar[n]quinones leads to tubular dimeric structures joined by 2n CH···O nonclassical hydrogen bonds (HBs) with binding energies about 2 kcal/mol per HB. The longitudinal extension of the supramolecular self‐assembly of pillar[n]quinone may be adjustable through forming and breaking their HBs by controlling the surrounding environment. The tunability of the diameter of the tubular structures can be achieved by changing the number of quinone units in the pillar[n]quinone. The electrostatic potential maps of pillar[n]quinones indicate that the positive charge in the interior cavity decreases as the number of quinone units increases. Chloride and bromide anions are chosen to examine the noncovalent anion‐π interactions between pillar[n]quinones and captured anions. The calculations show that the better compatibility of the effective radius of the anions with the interior dimension of pillar[n]quinone leads to larger stabilization energy. The selectivity of spatial matching and specific interaction of pillar[n]quinone is believed to possibly serve as a candidate for ionic and molecular recognition. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
The 3‐connectivity of a graph and the multiplicity of zero “2” of its chromatic polynomial
Authors: Dong F. M. , Koh K. M.
Published: June 2011

Let G be a graph of order n, maximum degree Δ, and minimum degree δ. Let P(G, λ) be the chromatic polynomial of G. It is known that the multiplicity of zero “0” of P(G, λ) is one if G is connected, and the multiplicity of zero “1” of P(G, λ) is one if G is 2‐connected. Is the multiplicity of zero “2” of P(G, λ) at most one if G is 3‐connected? In this article, we first construct an infinite family of 3‐connected graphs G such that the multiplicity of zero “2” of P(G, λ) is more than one, and then characterize 3‐connected graphs G with Δ + δ⩾n such that the multiplicity of zero “2” of P(G, λ) is at most one. In particular, we show that for a 3‐connected graph G, if Δ + δ⩾n and (Δ, δ3)≠(n−3, 3), where δ3 is the third minimum degree of G, then the multiplicity of zero “2” of P(G, λ) is at most one. © 2011 Wiley Periodicals, Inc. J Graph Theory
Inhibition of cyclin‐dependent kinase 5 but not of glycogen synthase kinase 3‐β prevents neurite retraction and tau hyperphosphorylation caused by secretable products of human T‐cell leukemia virus type I‐infected lymphocytes
Authors: Maldonado Horacio , Ramírez Eugenio , Utreras Elias , Pando María E. , Kettlun Ana M. , Chiong Mario , Kulkarni Ashok B. , Collados Lucía , Puente Javier , Cartier Luis , Valenzuela María A.
Published: June 2011

Human T‐cell leukemia virus type I (HTLV‐I)‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease characterized by selective loss of axons and myelin in the corticospinal tracts. This central axonopathy may originate from the impairment of anterograde axoplasmic transport. Previous work showed tau hyperphosphorylation at T181 in cerebrospinal fluid of HAM/TSP patients. Similar hyperphosphorylation occurs in SH‐SY5Y cells incubated with supernatant from MT‐2 cells (HTLV‐I‐infected lymphocytes secreting viral proteins, including Tax) that produce neurite shortening. Tau phosphorylation at T181 is attributable to glycogen synthase kinase 3‐β (GSK3‐β) and cyclin‐dependent kinase 5 (CDK5) activation. Here we investigate whether neurite retraction in the SH‐SY5Y model associates with concurrent changes in other tau hyperphosphorylable residues. Threonine 181 turned out to be the only tau hyperphosphorylated residue. We also evaluate the role of GSK3‐β and CDK5 in this process by using specific kinase inhibitors (LiCl, TDZD‐8, and roscovitine). Changes in both GSK3‐β active and inactive forms were followed by measuring the regulatory phosphorylable sites (S9 and Y216, inactivating and activating phosphorylation, respectively) together with changes in β‐catenin protein levels. Our results showed that LiCl and TDZD‐8 were unable to prevent MT‐2 supernatant‐mediated neurite retraction and also that neither Y216 nor S9 phosphorylations were changed in GSK3‐β. Thus, GSK3‐β seems not to play a role in T181 hyperphosphorylation. On the other hand, the CDK5 involvement in tau phosphorylation was confirmed by both the increase in its enzymatic activity and the absence of MT‐2 neurite retraction in the presence of roscovitine or CDK5 siRNA transfection. © 2011 Wiley‐Liss, Inc.
Neuroprotective effect of guanosine against glutamate‐induced cell death in rat hippocampal slices is mediated by the phosphatidylinositol‐3 kinase/Akt/ glycogen synthase kinase 3β pathway activation and inducible nitric oxide synthase inhibition
Authors: Molz Simone , Dal‐Cim Tharine , Budni Josiane , Martín‐de‐Saavedra M.D. , Egea Javier , Romero Alejandro , del Barrio Laura , Rodrigues Ana L.S. , López Manuela G. , Tasca Carla I.
Published: June 2011

Excitotoxicity and cell death induced by glutamate are involved in many neurodegenerative disorders. We have previously demonstrated that excitotoxicity induced by millimolar concentrations of glutamate in hippocampal slices involves apoptotic features and glutamate‐induced glutamate release. Guanosine, an endogenous guanine nucleoside, prevents excitotoxicty by its ability to modulate glutamate transport. In this study, we have evaluated the neuroprotective effect of guanosine against glutamate‐induced toxicity in hippocampal slices and the mechanism involved in such an effect. We have found that guanosine (100 μM) was neuroprotective against 1 mM glutamate‐induced cell death through the inhibition of glutamate release induced by glutamate. Guanosine also induced the phosphorylation and, thus, activation of protein kinase B (PKB/Akt), a downstream target of phosphatidylinositol‐3 kinase (PI3K), as well as phosphorylation of glycogen synthase kinase 3β, which has been reported to be inactivated by Akt after phosphorylation at Ser9. Glutamate treated hippocampal slices showed increased inducible nitric oxide synthase (iNOS) expression that was prevented by guanosine. Slices preincubated with SNAP (an NO donor), inhibited the protective effect of guanosine. LY294002 (30 μM), a PI3K inhibitor, attenuated guanosine‐induced neuroprotection, guanosine prevention of glutamate release, and guanosine‐induced GSK3βSer9 phosphorylation but not guanosine reduction of glutamate‐induced iNOS expression. Taken together, the results of this study show that guanosine protects hippocampal slices by a mechanism that involves the PI3K/Akt/GSK3βSer9 pathway and prevention of glutamate‐induced glutamate release. Furthermore, guanosine also reduces glutamate‐induced iNOS by a PI3K/Akt‐independent mechanism. © 2011 Wiley‐Liss, Inc.
High‐throughput analysis of drug dissociation from serum proteins using affinity silica monoliths
Authors: Yoo Michelle J. , Hage David S.
Published: June 2011

A noncompetitive peak decay method was used with 1 mm×4.6 mm id silica monoliths to measure the dissociation rate constants (kd) for various drugs with human serum albumin (HSA) and α1‐acid glycoprotein (AGP). Flow rates up to 9 mL/min were used in these experiments, resulting in analysis times of only 20–30 s. Using a silica monolith containing immobilized HSA, dissociation rate constants were measured for amitriptyline, carboplatin, cisplatin, chloramphenicol, nortriptyline, quinidine, and verapamil, giving values that ranged from 0.37 to 0.78 s−1. Similar work with an immobilized AGP silica monolith gave kd values for amitriptyline, nortriptyline, and lidocaine of 0.39–0.73 s−1. These kd values showed good agreement with values determined for drugs with similar structures and/or affinities for HSA or AGP. It was found that a kd of up to roughly 0.80 s−1 could be measured by this approach. This information made it possible to obtain a better understanding of the advantages and possible limitations of the noncompetitive peak decay method and in the use of affinity silica monoliths for the high‐throughput analysis of drug–protein dissociation.
Computational study on OH radical reaction with CHF2CHFCHF2(HFC‐245ea) between 200 and 400 K
Authors: Ali Mohamad Akbar , Rajakumar B.
Published: June 2011

The rate coefficients of the CHF2CHFCHF2 (HFC‐245ea) + OH reaction were computed using G3B3 theory in the temperature range 200 and 400 K. Geometries were optimized for all reactants, transition states, and products at the B3LYP level of theory using 6‐31G* and 6‐311++G** basis sets. Three rotamers (R1, R2, and R3) of CHF2CHFCHF2 were identified using a potential energy surface scan. Thirteen independent transition states were identified and confirmed by intrinsic reaction coordinate calculations. The kinetic parameters due to all different transition states are presented in this paper. All the three rotamers were taken into account in computing the rate coefficients. Throughout the temperature range of this study, rotamer R3 contributes significantly (more than 90%), whereas the other two rotamers R1 and R2 contribute less to the total rate coefficient. The rate coefficients for the title reaction were computed to be k = (1.86 ± 0.17) × 10−13 exp[−(748±26)/T] cm3 molecule−1s−1 and (1.25 ± 0.23) × 10−13 exp[−(587±50)/T] cm3molecule−1 s−1 with Wigner's and Eckart's unsymmetrical tunneling methods, respectively, and they are in reasonable agreement with the experimentally measured ones. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 418–430, 2011
Cellulose‐Based Sustainable Polymers: State of the Art and Future Trends
Authors: Rose Marcus , Palkovits Regina
Published: June 2011

Nowadays, nearly all polymeric materials are produced from crude oil‐derived monomers. With the steadily increasing demand for oil‐based products and their decreasing availability in the near future, one of the main challenges of mankind is the replacement of crude oil as raw material by renewable resources such as biomass. So far, only a few polymers are available derived directly from cellulose as a main component of biomass by regeneration. On the other hand, a significant potential lies in the production of polymers from cellulose‐derived monomers. A huge variety of different monomers is already available by convenient catalytic processes. This feature article focuses on the current status of mono‐ and resulting polymers derived either directly from cellulose processing and regeneration or by catalytic conversion to a number of monomers for the production of novel polymers and co‐polymers.

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Simultaneous Detection and Removal of Mercury Ions in Aqueous Solution with Fluorescent Conjugated Polymer‐Based Sensor Ensemble
Authors: Kwon Na Young , Kim Daigeun , Son Ji Hye , Jang Geun Seok , Lee Jung Hyo , Lee Taek Seung
Published: June 2011

A water‐soluble, sulfur‐containing fluorescent conjugated polymer exhibits a visible fluorescence color change for detection of mercury in the presence of thymine. A new concept provides the design of a sensor ensemble using a simple combination method. This strategy avoids the need for complicated design and synthesis of a recognition group, eliminating the tedious synthetic efforts for the preparation of a sensor material.

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Altered eye‐to‐foot coordination in standing parkinsonian patients during large gaze and whole‐body reorientations
Authors: Anastasopoulos Dimitri , Ziavra Nafsica , Savvidou Eugenia , Bain Peter , Bronstein Adolfo M.
Published: June 2011

We investigated whether turning problems in Parkinson's disease may be the result of abnormal horizontal multisegmental angular coordination. Ten mildly affected patients and controls stood upright and voluntarily reoriented eyes and body to illuminated targets of eccentricities up to ±180 degrees. The effects of target location, visibility, and predictability on movement parameters were evaluated. Patients' latencies were normal. Control subjects foveated large eccentricity targets with a single gaze shift in approximately 30% of predictable trials. Patients rarely did so (10% of predictable trials) because of reduced head‐in‐space and trunk velocity. This resulted in massive foveation delays in patients—an average of half a second for displacements of 180 degrees. The covariation of eye, head, and trunk rotations was quantified statistically by means of principal components analysis. In both groups, the combined movement was initially stereotyped and two principal components accounted for nearly all data variance—the original three mechanical degrees of freedom (i.e., eye‐head‐trunk) are reduced to two kinematic degrees of freedom. However, in patients, the eye contributed more, and the head and trunk less, to the gaze shift than in control subjects. Although the eye‐to‐foot turning synergy is preserved in early‐stage parkinsonism, quantitative differences are prominent, particularly a larger ocular (and smaller head‐trunk) contribution in patients. Turning problems in Parkinson's disease do not result from inability to assemble multisegmental movements, as patients' ability to control numerous degrees of freedom is preserved. However, trunk bradykinesia reduces the frequency of single‐step gaze shifts, thus prolonging target acquisition time. Preserved eye motion compensates for trunk slowness. © 2011 Movement Disorder Society
Pathological gambling in Parkinson's disease—a review of the literature
Authors: Djamshidian Atbin , Cardoso Francisco , Grosset Donald , Bowden‐Jones Henrietta , Lees Andrew J.
Published: June 2011

The prevalence of pathological gambling is 3.4% to 6% in treated Parkinson's disease, which is higher than the background population rate. In this review we discuss current evidence to indicate that dopamine agonists are much more likely to trigger this behavior than either L‐dopa or selective monoamine oxidase B inhibitor monotherapy. New insights from recent behavioral and functional imaging studies and possible treatment approaches are also covered. A PubMed literature search using the terms “gambling” and “Parkinson's disease,” “impulse control disorder,” “impulsive compulsive behaviour,” “dopamine agonist,” of individual dopamine agonists, and of ongoing drug trials, using http://www.clinicaltrials.gov, was carried out for the period up to January 2011. © 2011 Movement Disorder Society
MDS task force on mild cognitive impairment in Parkinson's disease: Critical review of PD‐MCI
Authors: Litvan Irene , Aarsland Dag , Adler Charles H. , Goldman Jennifer G. , Kulisevsky Jaime , Mollenhauer Brit , Rodriguez‐Oroz Maria C. , Tröster Alexander I. , Weintraub Daniel
Published: June 2011

There is controversy regarding the definition and characteristics of mild cognitive impairment in Parkinson's disease. The Movement Disorder Society commissioned a Task Force to critically evaluate the literature and determine the frequency and characteristics of Parkinson's disease–mild cognitive impairment and its association with dementia. A comprehensive PubMed literature review was conducted using systematic inclusion and exclusion criteria. A mean of 26.7% (range, 18.9%–38.2%) of nondemented patients with Parkinson's disease have mild cognitive impairment. The frequency of Parkinson's disease–mild cognitive impairment increases with age, disease duration, and disease severity. Impairments occur in a range of cognitive domains, but single domain impairment is more common than multiple domain impairment, and within single domain impairment, nonamnestic is more common than amnestic impairment. A high proportion of patients with Parkinson's disease–mild cognitive impairment progress to dementia in a relatively short period of time. The primary conclusions of the Task Force are that: (1) Parkinson's disease–mild cognitive impairment is common, (2) there is significant heterogeneity within Parkinson's disease–mild cognitive impairment in the number and types of cognitive domain impairments, (3) Parkinson's disease–mild cognitive impairment appears to place patients at risk of progressing to dementia, and (4) formal diagnostic criteria for Parkinson's disease–mild cognitive impairment are needed. © 2011 Movement Disorder Society
Contrast at high field: Relaxation times, magnetization transfer and phase in the rat brain at 16.4 T
Authors: Pohmann Rolf , Shajan G. , Balla D. Z.
Published: June 2011

As field strength increases, the magnetic resonance imaging contrast parameters like relaxation times, magnetization transfer or image phase change, causing variations in contrast and signal‐to‐noise ratio. To obtain reliable data for these parameters at 16.4 T, high‐resolution measurements of the relaxation times T1, T2 and T2*, as well as of the magnetization transfer ratio and the local frequency in the rat brain were performed. Tissue‐specific values were obtained for up to 17 brain structures to assess image contrast. The measured parameters were compared to those found at different field strengths to estimate contrast and signal behavior at increasing field. T1 values were relatively long with (2272 ± 113) ms in cortex and (2073 ± 97) ms in white matter, but did not show a tendency to converge, leading to an almost linear increase in signal‐to‐noise ratio and still growing contrast‐to‐noise ratio. T2 was short with (25 ± 2) ms in cortex and (20 ± 1) ms in white matter. Magnetization transfer effects increase by around 25% compared to published 4.7 T data, which leads to improved contrast. The image phase, as novel and high‐field specific contrast mechanism, is shown to obtain good contrast in deep brain regions with increasing signal‐to‐noise ratio up to high field strengths. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Compressed‐sensing motion compensation (CosMo): A joint prospective–retrospective respiratory navigator for coronary MRI
Authors: Moghari Mehdi H. , Akçakaya Mehmet , O'Connor Alan , Basha Tamer A. , Casanova Michele , Stanton Douglas , Goepfert Lois , Kissinger Kraig V. , Goddu Beth , Chuang Michael L. , Tarokh Vahid , Manning Warren J. , Nezafat Reza
Published: June 2011

Prospective right hemidiaphragm navigator (NAV) is commonly used in free‐breathing coronary MRI. The NAV results in an increase in acquisition time to allow for resampling of the motion‐corrupted k‐space data. In this study, we are presenting a joint prospective–retrospective NAV motion compensation algorithm called compressed‐sensing motion compensation (CosMo). The inner k‐space region is acquired using a prospective NAV; for the outer k‐space, a NAV is only used to reject the motion‐corrupted data without reacquiring them. Subsequently, those unfilled k‐space lines are retrospectively estimated using compressed sensing reconstruction. We imaged right coronary artery in nine healthy adult subjects. An undersampling probability map and sidelobe‐to‐peak ratio were calculated to study the pattern of undersampling, generated by NAV. Right coronary artery images were then retrospectively reconstructed using compressed‐sensing motion compensation for gating windows between 3 and 10 mm and compared with the ones fully acquired within the gating windows. Qualitative imaging score and quantitative vessel sharpness were calculated for each reconstruction. The probability map and sidelobe‐to‐peak ratio show that the NAV generates a random undersampling k‐space pattern. There were no statistically significant differences between the vessel sharpness and subjective score of the two reconstructions. Compressed‐sensing motion compensation could be an alternative motion compensation technique for free‐breathing coronary MRI that can be used to reduce scan time. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Multi‐contrast reconstruction with Bayesian compressed sensing
Authors: Bilgic Berkin , Goyal Vivek K , Adalsteinsson Elfar
Published: June 2011

Clinical imaging with structural MRI routinely relies on multiple acquisitions of the same region of interest under several different contrast preparations. This work presents a reconstruction algorithm based on Bayesian compressed sensing to jointly reconstruct a set of images from undersampled k‐space data with higher fidelity than when the images are reconstructed either individually or jointly by a previously proposed algorithm, M‐FOCUSS. The joint inference problem is formulated in a hierarchical Bayesian setting, wherein solving each of the inverse problems corresponds to finding the parameters (here, image gradient coefficients) associated with each of the images. The variance of image gradients across contrasts for a single volumetric spatial position is a single hyperparameter. All of the images from the same anatomical region, but with different contrast properties, contribute to the estimation of the hyperparameters, and once they are found, the k‐space data belonging to each image are used independently to infer the image gradients. Thus, commonality of image spatial structure across contrasts is exploited without the problematic assumption of correlation across contrasts. Examples demonstrate improved reconstruction quality (up to a factor of 4 in root‐mean‐square error) compared with previous compressed sensing algorithms and show the benefit of joint inversion under a hierarchical Bayesian model. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Serial MRI characterization of the functional and morphological changes in mouse lung in response to cardiac remodeling following myocardial infarction
Authors: Alsaid Hasan , Bao Weike , Rambo Mary V. , Logan Gregory A. , Figueroa David J. , Lenhard Stephen C. , Kotzer Charles J. , Burgert Mark E. , Willette Robert N. , Ferrari Victor A. , Jucker Beat M.
Published: June 2011

The temporal evolution of heart failure and associated pulmonary congestion in rodent heart failure models has not yet been characterized simultaneously and noninvasively. In this study, MRI was used to assess the serial progression of left‐ventricular dysfunction and lung congestion in mice following myocardial infarction (MI). Cardiac and lung 1H MRI was performed at baseline and every 3 days up to 13 days postsurgery in sham and MI mice. Respiratory parameters and terminal lung mechanics were assessed followed by histological analysis. MRI revealed that the MI induced significant pulmonary congestion/edema as detected by increased MRI signal intensity and was associated with increased lung volume and reduced cardiac contractility. Pulmonary function was also depressed in MI‐mice, reflected by a reduced tidal volume and a low minute ventilation rate. Additionally, MI significantly increased lung resistance, markedly reduced lung compliance and total lung capacity and significantly increased lung weights by 57%. Significant correlations were observed between the MRI measured lung congestion, lung volume, ejection fraction, and lung wet‐weight parameters. This study demonstrates that MRI may be of significant value in evaluating therapies aimed at primary intervention for lung congestion and secondary prevention of unfavorable cardiac remodeling. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Whole brain susceptibility mapping using compressed sensing
Authors: Wu Bing , Li Wei , Guidon Arnaud , Liu Chunlei
Published: June 2011

The derivation of susceptibility from image phase is hampered by the ill‐conditioned filter inversion in certain k‐space regions. In this article, compressed sensing is used to compensate for the k‐space regions where direct filter inversion is unstable. A significantly lower level of streaking artifacts is produced in the resulting susceptibility maps for both simulated and in vivo data sets compared to outcomes obtained using the direct threshold method. It is also demonstrated that the compressed sensing based method outperforms regularization based methods. The key difference between the regularized inversions and compressed sensing compensated inversions is that, in the former case, the entire k‐space spectrum estimation is affected by the ill‐conditioned filter inversion in certain k‐space regions, whereas in the compressed sensing based method only the ill‐conditioned k‐space regions are estimated. In the susceptibility map calculated from the phase measurement obtained using a 3T scanner, not only are the iron‐rich regions well depicted, but good contrast between white and gray matter interfaces that feature a low level of susceptibility variations are also obtained. The correlation between the iron content and the susceptibility levels in iron‐rich deep nucleus regions is studied, and strong linear relationships are observed which agree with previous findings. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
On the performance of T2* correction methods for quantification of hepatic fat content
Authors: Reeder Scott B. , Bice Emily K. , Yu Huanzhou , Hernando Diego , Pineda Angel R.
Published: June 2011

Nonalcoholic fatty liver disease is the most prevalent chronic liver disease in Western societies. MRI can quantify liver fat, the hallmark feature of nonalcoholic fatty liver disease, so long as multiple confounding factors including T2* decay are addressed. Recently developed MRI methods that correct for T2* to improve the accuracy of fat quantification either assume a common T2* (single‐T2*) for better stability and noise performance or independently estimate the T2* for water and fat (dual‐T2*) for reduced bias, but with noise performance penalty. In this study, the tradeoff between bias and variance for different T2* correction methods is analyzed using the Cramér‐Rao bound analysis for biased estimators and is validated using Monte Carlo experiments. A noise performance metric for estimation of fat fraction is proposed. Cramér‐Rao bound analysis for biased estimators was used to compute the metric at different echo combinations. Optimization was performed for six echoes and typical T2* values. This analysis showed that all methods have better noise performance with very short first echo times and echo spacing of ∼π/2 for single‐T2* correction, and ∼2π/3 for dual‐T2* correction. Interestingly, when an echo spacing and first echo shift of ∼π/2 are used, methods without T2* correction have less than 5% bias in the estimates of fat fraction. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Spurenstoffe beeinflussen das Zusammenleben
Authors: Klaschka Ursula
Published: June 2011

Stören Duftstoffe aus Parfüm, Kosmetika, Wasch‐ und Reinigungsmitteln die Kommunikation und das Leben von Umweltorganismen? Die Erforschung dieses Infochemikalieneffekts ist ein neuer Zweig der Ökotoxikologie.
Die Risiken beim Einkauf
Authors: Hermann Marco
Published: June 2011

Naturkatastrophen, Rohstoffknappheit, Preisänderungen, volatile Märkte oder politische Instabilität — Lieferketten sind vielen Risiken ausgesetzt. Zusammen mit hohen Effizienzanforderungen entstehen instabile Lieferketten. Wie lässt sich dagegen steuern?
On the nature of bladder sensation: The concept of sensory modulation
Authors: De Wachter S.G. , Heeringa R. , van Koeveringe G.A. , Gillespie J.I.
Published: June 2011

Aims

Going to the toilet is an essential everyday event. Normally, we do not give much thought to the sensations and factors that trigger voiding behavior: we just go. For many people, this apparently simple task is complicated and dominates their life. They have strong sensations and sudden desires to void, often resulting in incontinence. It is therefore important that we understand the origins for this functional change and identify means to alleviate it.

Methods

Literature survey.

Results

A considerable body of work has focused on this problem and ideas and concepts on the nature of bladder sensations are embedded in the literature. In this paper we argue the necessity to return to first principles and a re‐examination of the problem. We explore the use of focus groups to identify relevant bladder sensation and what triggers ‘bladder’ behavior. We argue that there are differences in what can be described as ‘introspective bladder sensations’ and the sensations reported immediately before a void, ‘void sensations’. Finally, we propose an alternative model describing how peripheral information generating ‘introspective sensations’ and ‘void sensations’ might be different but interrelated sensations. By exploring such ideas and identifying such complexity it is our intention to stimulate debate and generate further research in the field in order to understand better the physiology of bladder sensation and the pathology of increased urge, frequency and incontinence.

Conclusions

Review of the literature on bladder sensation and the established ideas suggests that we might be missing something and the problem of normal and increased sensation and of urgency may be much more complex. Neurourol. Urodynam. 30:1220–1226, 2011. © 2011 Wiley‐Liss, Inc.