bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between group sunspot numbers and Wolf sunspot numbers
Authors: Li K.J. , Liang H.F.
Published: July 2010

Continuous wavelet transform and cross‐wavelet transform have been used to investigate the phase periodicity and synchrony of the monthly mean Wolf (Rz) and group (Rg) sunspot numbers during the period of June 1795 to December 1995. The Schwabe cycle is the only one common period in Rg and Rz, but it is not well‐defined in case of cycles 5–7 of Rg and in case of cycles 5 and 6 of Rz. In fact, the Schwabe period is slightly different in Rg and Rz before cycle 12, but from cycle 12 onwards it is almost the same for the two time series. Asynchrony of the two time series is more obviously seen in cycles 5 and 6 than in the following cycles, and usually more obviously seen around the maximum time of a cycle than during the rest of the cycle. Rg is found to fit Rz better in both amplitudes and peak epoch during the minimum time time of a solar cycle than during the maximum time of the cycle, which should be caused by their different definition, and around the maximum time of a cycle, Rg is usually less than Rz. Asynchrony of Rg and Rz should somewhat agree with different sunspot cycle characteristics exhibited by themselves (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical modelling of the vertical structure and dark halo parameters in disc galaxies
Authors: Khoperskov A. , Bizyaev D. , Tiurina N. , Butenko M.
Published: July 2010

The non‐linear dynamics of bending instability and vertical structure of a galactic stellar disc embedded into a spherical halo are studied with N‐body numerical modelling. Development of the bending instability in stellar galactic disc is considered as the main factor that increases the disc thickness. Correlation between the disc vertical scale height and the halo‐to‐disc mass ratio is predicted from the simulations. The method of assessment of the spherical‐to‐disc mass ratio for edge‐on spiral galaxies with a small bulge is considered. Modelling of eight edge‐on galaxies: NGC 891, NGC 4738, NGC 5170, UGC 6080, UGC 7321, UGC 8286, UGC 9422 and UGC 9556 is performed. Parameters of stellar discs, dark haloes and bulges are estimated. The lower limit of the dark‐to‐luminous mass ratio in our galaxies is of the order of one within the limits of their stellar discs. The dark haloes dominate by mass in the galaxies with very thin stellar discs (NGC 5170, UGC 7321 and UGC 8286) (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparisons of the environmental dependence of galaxy properties between blue late‐types and red late‐types
Authors: Deng X.F. , Xin Y. , Jiang P. , Wu P. , Luo C.H.
Published: July 2010

Using the volume‐limited Main galaxy sample of the Sloan Digital Sky Survey Data Release 6 (SDSS DR6), we investigate the difference of the environmental dependence of galaxy properties between blue late‐types and red late‐types, and find that the galaxy luminosity and concentration index are almost independent of the local density in the two samples. We also note a strong correlation between g – r color and the environment in the red late‐type sample, while this correlation is very weak in the blue late‐type sample (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A self‐consistent treatment of the electromotive force in magnetohydrodynamics for large diffusivities
Authors: Courvoisier A. , Hughes D.W. , Proctor M.R.E.
Published: July 2010

The coupled equations that describe the effect of large‐scale magnetic and velocity fields on forced high‐diffusivity magnetohydrodynamic flows are investigated through an extension of mean field electrodynamics. Our results generalise those of Rädler & Brandenburg (2010), who consider a similar situation but assume that the effect of the Lorentz force on the momentum equation can be neglected. New mean coupling terms are shown to appear, which can lead to large‐scale growth of magnetic and velocity fields even when the usual a‐effects are absent (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Big Bear Solar Observatory CaIIK‐line index for solar cycle 23
Authors: Naqvi M.F. , Marquette W.H. , Tritschler A. , Denker C.
Published: July 2010

We present an analysis of 2634 CaIIK‐line full‐disk filtergrams obtained with the 15‐cm aperture photometric full‐disk telescope at Big Bear Solar Observatory during the period from 1996 January 1 to 2005 October 24. Using limb darkening corrected and contrast enhanced filtergrams, solar activity indices were derived, which are sensitive to the 11‐year solar activity cycle and 27‐day rotational period of plages around active regions and the bright chromospheric network. The present work extends an earlier study (solar cycle 22), which was based on video data. The current digital data are of much improved quality with higher spatial resolution and a narrower passband ameliorating photometric accuracy. The time series of chromospheric activity indices cover most of solar cycle 23. One of the most conspicuous features of the CaIIK indices is the secondary maximum in late 2001/early 2002 after an initial decline of chromospheric activity during the first half of 2001. We conclude that a secular trend exists in the CaIIK indices, which has its origin in the bright chromospheric network and brightenings related to decaying active regions. Superposed on this secular trend are the signatures of recurring, long‐lived active regions, which are clusters of persistent and continuously emerging magnetic flux. Such features are less visible, when the activity belts on both side of the equator are devoid of the brightenings related to decaying active regions as was the case in October/November 2003 at a time when a superactivity complex including several naked‐eye sunspots emerged (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conformation dependence of the CαDα stretch mode in peptides: Side‐chain influence in dipeptide structures
Authors: Mirkin Noemi G. , Krimm Samuel
Published: July 2010

We have shown by theoretical studies of alanine peptides that the CαDα stretch frequency could be particularly useful for determining peptide structure because of its sensitivity to the φ,ψ torsion angles at the Cα atom. To demonstrate that this is a robust methodology worthy of experimental exploration, we have also shown that this mode is even more determinative of conformation in aqueous solution, mainly as a result of the development of differential CαDα···O(water) interactions. As further assurance, we now determine the influence of the side chain on this band, showing for aliphatic, a polar, and an aromatic side chains that the dependence is minor and explaining why this is also expected for other side chains. These results should stimulate new experimental methodologies in the field of peptide structure determination. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 1065–1071, 2010.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Laparoscopic gastric surgery in an enhanced recovery programme
Authors: Grantcharov T P , Kehlet H
Published: July 2010

Background

Laparoscopy is associated with less pain and organ dysfunction than open surgery. Improved perioperative care (enhanced recovery programmes, fast-track methodology) has also led to reduced morbidity and a shorter hospital stay. The effects of a combination of laparoscopic resection and accelerated recovery have not been examined previously in the context of gastric surgery.

Methods

This was a prospective study of 32 consecutive patients undergoing laparoscopic gastric resection combined with an enhanced recovery protocol (early oral intake, no drains or nasogastric tubes, no epidural analgesia, use of a urinary catheter for less than 24 h and planned discharge 72 h after surgery). Outcomes included length of hospital stay, intraoperative and postoperative complications, readmission rate and 30-day mortality.

Results

Operative procedures were elective distal or subtotal gastrectomy (22 patients) and total gastrectomy (10). Median length of hospital stay was 4 (range 2–30) days. There were two major complications: postoperative bleeding requiring reoperation and pulmonary embolism. Two patients required readmission, one for a wound abscess and one for treatment of a urinary tract infection. There were no deaths within 30 days.

Conclusion

Minimally invasive gastrectomy with enhanced postoperative recovery results in a short hospital stay and low morbidity rate.
Retroperitoneal endoscopic adrenalectomy is safe and effective
Authors: Schreinemakers J M J , Kiela G J , Valk G D , Vriens M R , Rinkes I H M Borel
Published: July 2010

Background

The aim of this study was to review an experience with retroperitoneal endoscopic adrenalectomy (REA). This is the procedure of choice for adrenal tumours at this institution.

Methods

Between 1997 and 2008, 112 REAs were performed in a single university centre. Data were retrieved retrospectively from a prospectively collected database, including information on patient demographics, surgical procedure, complications and hospital stay.

Results

One hundred and twelve REAs were carried out successfully in 105 patients, including seven bilateral adrenalectomies. Thirty-nine patients with unilateral adrenal disease had a phaeochromocytoma, of whom 16 had multiple endocrine neoplasia syndrome type 2, 21 patients had Cushing's disease and 20 had Conn's disease. Median body mass index was 27 (interquartile range 23–29) kg/m2. The median duration of unilateral operations was 100 (90–130) min with a median blood loss of 5 ml. Median tumour size was 3·1 (2·0–4·4) cm. Conversion from REA to open surgery was needed in two patients. Seven patients experienced postoperative complications (2 major, 5 minor). One patient needed a reoperation. The median postoperative hospital stay was 3 days. A learning curve with a significant decrease in operating time was observed over the years.

Conclusion

REA appears to be a safe and effective surgical technique for adrenal gland tumours up to 6 cm in diameter, with a minimal complication rate.
Development and validation of GC/MS method for determination of pramipexole in rat plasma
Authors: Panchal Jayesh G. , Patel Ravindra V. , Menon Shobhana K.
Published: July 2010

A simple, rapid and sensitive method has been developed and validated for the determination of pramipexole in rat plasma by using gas chromatography mass spectrometry. The lower limit of quantification (LLOQ) is superior to the other reported LC‐MS/MS methods. After being made alkaline with NaOH, plasma samples (0.1 mL) were subjected to liquid–liquid exteraction using methyl‐t‐butyl ether. Analytes were determined using electron impact ionization in a single quadrupole mass spectrometer. GC/MS was performed in the selected ion monitoring mode using target ions atm/z211, 212 and 152 for pramipexole andm/z194 and 165 for caffeine as internal standard. A linear calibration curve was plotted over the range of 20–1000 pg/mL for pramipexole (r2> 0.996). The LLOQ was 20.0 pg/mL, respectively, which offered high sensitivity and selectivity enough for bioanalytical investigation. Inter‐ and intraday precisions ranged from 0.3 to 8.8% and from 0.9 to 11.33%, respectively. The recovery of pramipexole from plasma ranged from 82.4 ± 7.1 to 87.8 ± 5.7%. The method fulfills all standards required for bioanalytical methods and can be successfully applied to a pharmacokinetic study of pramipexole in rats. Copyright © 2010 John Wiley & Sons, Ltd.
u‐TA: A ubiquitous teaching assistant using knowledge retrieval and adaptive learning techniques
Authors: Huang Lu‐Hui , Dow Chyi‐Ren , Li Yi‐Hsung , Hsuan Pa
Published: July 2010

Using mobile agents to assist students in virtual learning environments has become increasingly common for hands‐on experiments. Although virtual learning environments provide mobile agents as a platform for services to learners, one type of mobile agent only serves in one course, bringing possible benefits to users. This study was conducted to use agent techniques to construct a ubiquitous teaching assistant (u‐TA) for assisting students solve problems in laboratory courses. We gave the u‐TA enhanced social skills so that it can reduce the burden on teachers. The proposed u‐TA system consists of both Web‐based and instant messenger‐based (IM‐based) interfaces, and the u‐TA can learn from other agents by analyzing their dialogues. Experiments were conducted to evaluate the effectiveness of the u‐TA and the results show that the u‐TA can assist students and share the TA's workload in courses. The experimental results also demonstrated that the u‐TA has good communications ability; its two user interfaces can increase interactions with students. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 245–255, 2013
PlanetLab@UOC: A real lab over the Internet to experiment with distributed systems
Authors: Marquès Joan Manuel , Lazaro Daniel , Juan Angel A. , Vilajosana Xavier , Domingo Marc , Jorba Josep
Published: July 2010

This paper presents an innovative academic experience regarding the use of PlanetLab—an open large‐scale platform over the Internet—in engineering courses on distributed systems. By integrating a live‐deployment environment such as PlanetLab into distributed‐systems courses, software implementations developed by students can interact with instructors' implementations in a real Internet‐distributed scenario. To the best of our knowledge, this is the first experience regarding the use of the PlanetLab nodes available over Internet to teach distributed computing concepts to engineering students, since most of the existing literature on distributed‐systems courses describes only learning experiences in lab‐simulated or lab‐emulated scenarios. As discussed in this paper, experimenting with a real laboratory over the Internet adds some complexity to students' practical activities, but it also facilitates a deeper and more intensive learning experience. A survey among students shows some clear benefits of this approach over the use of simulation labs, as well as some pitfalls that must be avoided whenever possible. The paper ends with a set of recommendations for instructors that might want to design similar courses as well as with an overview of future work to be performed in this field. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 265–275, 2013
A Single Molecular Beacon Probe Is Sufficient for the Analysis of Multiple Nucleic Acid Sequences
Authors: Gerasimova Yulia V. , Hayson Aaron , Ballantyne Jack , Kolpashchikov Dmitry M.
Published: July 2010

Molecular beacon (MB) probes are dual‐labeled hairpin‐shaped oligodeoxyribonucleotides that are extensively used for real‐time detection of specific RNA/DNA analytes. In the MB probe, the loop fragment is complementary to the analyte: therefore, a unique probe is required for the analysis of each new analyte sequence. The conjugation of an oligonucleotide with two dyes and subsequent purification procedures add to the cost of MB probes, thus reducing their application in multiplex formats. Here we demonstrate how one MB probe can be used for the analysis of an arbitrary nucleic acid. The approach takes advantage of two oligonucleotide adaptor strands, each of which contains a fragment complementary to the analyte and a fragment complementary to an MB probe. The presence of the analyte leads to association of MB probe and the two DNA strands in quadripartite complex. The MB probe fluorescently reports the formation of this complex. In this design, the MB does not bind the analyte directly; therefore, the MB sequence is independent of the analyte. In this study one universal MB probe was used to genotype three human polymorphic sites. This approach promises to reduce the cost of multiplex real‐time assays and improve the accuracy of single‐nucleotide polymorphism genotyping.
Molecular Recognition of Peloruside A by Microtubules. The C24 Primary Alcohol is Essential for Biological Activity
Authors: Pera Benet , Razzak Mina , Trigili Chiara , Pineda Oriol , Canales Angeles , Buey Rubén M. , Jiménez‐Barbero Jesús , Northcote Peter T. , Paterson Ian , Barasoain Isabel , Díaz José Fernando
Published: July 2010

Peloruside is a microtubule‐stabilizing agent that targets the same site as laulimalide. It binds to microtubules with a 1:1 stoichiometry and with a binding affinity in the low‐μM range; thereby reducing the number of microtubular protofilaments in the same way as paclitaxel. Although the binding affinity of the compound is comparable to that of the low‐affinity stabilizing agent sarcodictyin, peloruside is more active in inducing microtubule assembly and is more cytotoxic to tumor cells; this suggests that the peloruside site is a more effective site for stabilizing microtubules. Acetylation of the C24 hydroxyl group results in inactive compounds. According to molecular modeling, this substitution at the C24 hydroxyl group presumably disrupts the interaction of the side chain with Arg320 in the putative binding site on α‐tubulin. The binding epitope of peloruside on microtubules has been studied by using NMR spectroscopic techniques, and is compatible with the same binding site.
Cu Nanoparticles in PEG: A New Recyclable Catalytic System for N‐Arylation of Amines with Aryl Halides
Authors: Kidwai Mazaahir , Mishra Neeraj Kumar , Bhardwaj Saurav , Jahan Anwar , Kumar Ajeet , Mozumdar Subho
Published: July 2010

A new protocol for the N‐arylation of aryl halides with anilines using Cu nanoparticles in polyethylene glycol (PEG) as an efficient and reusable catalytic system has been developed. The reaction did not require any cocatalyst. Various solvents were screened, and PEG400 provided the best results. The studies showed that the mechanism of catalytic action is dependent on the size of the nanoparticles. The Cu nanoparticles and PEG were recyclable and retained their activity. This newly developed protocol was also found to be suitable for the cross coupling of NH heterocycles with iodobenzene. The present methodology offers several advantages, such as excellent yields, short reaction times, and milder reaction conditions.
Biocatalytic Production of Coenzyme A Analogues
Authors: Strauss Erick , de Villiers Marianne , Rootman Ilse
Published: July 2010

Coenzyme A (CoA) analogues are widely used as tools in chemical biology. Their applications include being used as inhibitors and mechanistic probes of CoA‐dependent enzymes, and in the labeling of especially carrier proteins active in polyketide and nonribosomal peptide synthesis with fluorescent probes or affinity tags, or with chemically reactive cross‐linking moieties. The preparation of CoA analogues has been simplified tremendously since the discovery of the CoA biosynthetic enzymes. Consequently a large number of such analogues have been prepared in recent years by the biotransformation of pantothenamide precursors (a bottom‐up approach) or by aminolysis of activated pre‐CoA thioesters (a top‐down approach). This Minireview provides an analysis of the biosynthetic enzymes used in the biocatalytic production of CoA analogues, an overview of the different ways in which they are currently applied and a description of the types of CoA analogues that are currently easily accessed by such methods.
Asymmetric Retro‐Henry Reaction Catalyzed by Hydroxynitrile Lyase from Hevea brasiliensis
Authors: Yuryev Ruslan , Briechle Sebastian , Gruber‐Khadjawi Mandana , Griengl Herfried , Liese Andreas
Published: July 2010

Hydroxynitrile lyase from Hevea brasiliensis (HbHNL) is a promiscuous biocatalyst that, besides the native cyanohydrin reaction, also catalyzes the asymmetric Henry reaction yielding (S)‐β‐nitroalcohols with high enantiomeric excess. Since the Henry reaction is reversible, the enzyme can be also utilized for the production (R)‐enantiomers by means of resolution of racemic β‐nitroalcohols. Herein the biocatalytic retro‐Henry reaction is studied using the cleavage of 2‐nitro‐1‐phenylethanol as a model system. The main problem that prevents high levels of conversion or high ee values during the cleavage of the β‐nitroalcohol is the formation of benzaldehyde, which is known to be a strong enzyme inhibitor. The product inhibition is overcome by performing the biocatalytic retro‐Henry reaction in the presence of HCN, which reacts in situ with benzaldehyde and converts it to the less‐inhibitive mandelonitrile. By using such a reaction cascade, it was possible to conduct the resolution practically to completion (95 % ee, 49 % conversion). Furthermore, the catalyst productivity achieved during the resolution was ten times higher than that in the HbHNL‐catalyzed synthesis of (S)‐2‐nitro‐1‐phenylethanol by condensation of benzaldehyde and nitromethane.
Filtering of Clay Colloids in Bentonite Detritus Material
Authors: Richards T. , Neretnieks I.
Published: July 2010

Bentonite clay consists of two types of materials, small nanoscale smectite particles and larger accessory material particles. When used as a barrier, it is important that as little material as possible is lost. This loss may occur if water with low salinity passes by the bentonite clay. First, the clay will swell and then the smectite particles can solubilize. This study investigates under which circumstances the material can form a filter cake of the accessory material and slow down or stop the penetration of smectite through the filter cake. It has been shown that it is possible to form such a filter cake and that the filter cake can be further improved by adding other particles.
Advances in Pore Structure Evaluation by Porometry
Authors: Jena A. , Gupta K.
Published: July 2010

The principle and technique of porometry, the measurable pore structure characteristics, and the significance of the measured quantities are reviewed. Advances in porometry and their applications are considered. Recently developed innovative and novel techniques used for porometry are also discussed.
Parallel factor analysis of EEM of the fluorescence of carbon dots nanoparticles
Authors: Leitão João M. M. , Gonçalves Helena , da Silva Joaquim C. G. Esteves
Published: July 2010

The effect of experimental factors [pH and Hg(II)] on the fluorescence excitation emission matrices (EEMs) of nanosensor carbon dots (CDs) was analyzed by multiway decomposition methods based on parallel factor (PARAFAC) analysis. PARAFAC analysis of the EEM structures identifies three components corresponding to two different‐sized CDs with the Hg(II) and pH profiles highly correlated plus a background. Parallel profiles with Linear Dependences (PARALIND) model with three components in the excitation–emission spectral modes and two components in the Hg(II) or pH mode gave similar results as PARAFAC, but is more useful from a theoretical point of view because PARALIND shows that the two different‐sized CDs have similar chemical reactivity toward Hg(II) and pH. PARAFAC2 was used as a trilinear confirmatory test of the data structures under analysis. Copyright © 2010 John Wiley & Sons, Ltd.
Structure–Activity Relationship Analysis of Pd–PEPPSI Complexes in Cross‐Couplings: A Close Inspection of the Catalytic Cycle and the Precatalyst Activation Model
Authors: Nasielski Joanna , Hadei Nilofaur , Achonduh George , Kantchev Eric Assen B. , O'Brien Christopher J. , Lough Alan , Organ Michael G.
Published: July 2010

A series of Pd–N‐heterocyclic carbene (Pd–NHC) complexes with various NHC, halide and pyridine ligands (PEPPSI (pyridine, enhanced, precatalyst, preparation, stabilisation and initiation) precatalysts) were prepared, and the effects of these ligands on catalyst activation and performance were studied in the Kumada–Tamao–Corriu (KTC), Negishi, and Suzuki–Miyaura cross‐coupling reactions. The lowered reactivity of more hindered 2,6‐dimethylpyridyl complex 4 in the Negishi and KTC reactions is consistent with slow reductive dimerisation of the organometallic reaction partner during precatalyst activation. Comparative rate studies of complexes 1, 4 and 5 in the KTC and Suzuki–Miyaura reactions verify that 4 activated more slowly than the others. A potential on/off mechanism of pyridine coordination to NHC–Pd0 is also plausible, in which the more basic pyridine stays bound for longer.
Promoted H2 Generation from NH3BH3 Thermal Dehydrogenation Catalyzed by Metal–Organic Framework Based Catalysts
Authors: Li Yaoqi , Song Ping , Zheng Jie , Li Xingguo
Published: July 2010

The application of ammonium borane (AB) as a hydrogen storage material is limited by the sluggish kinetics of H2 release. Two catalysts based on metal–organic frameworks (MOFs) have been prepared either by applying MOF as precursors or by the in situ reduction method. In the release of H2 from AB, the high H2 content of the whole system, the remarkably lower reaction onset temperature, the significantly increased H2 release rates at ≤90 °C, and the decreased reaction exothermicity have all been achieved with only 1.0 mol % MOF‐based catalyst. Moreover, the clear catalytic diversity of three catalysts has been observed and discussed. The in situ synthesized Ni0 sites and the MOF supports in the catalysts were proven to show significant and different effects to promote the catalytic activities. With MOF‐based catalysts, both the enhanced kinetics and the high H2 capacity of the AB system present great advantages for future use.
Characterization, Direct Electrochemistry, and Amperometric Biosensing of Graphene by Noncovalent Functionalization with Picket‐Fence Porphyrin
Authors: Tu Wenwen , Lei Jianping , Zhang Siyuan , Ju Huangxian
Published: July 2010

Reduced graphene oxide (RGO) was prepared and functionalized with picket‐fence porphyrin, 5,10,15,20‐tetrakis [αααα‐2‐trismethylammoniomethylphenyl] porphyrin iron(III) pentachloride (FeTMAPP), through π–π interactions. The resulting nanocomposite was characterized by atomic force microscopy (AFM); transmission electron microscopy (TEM); contact angle measurements; and fluorescence, Raman, and UV/Vis absorption spectroscopy. On account of the introduction of positively charged FeTMAPP, the functionalized RGO showed good dispersion in aqueous solution. The RGO could greatly accelerate the electron transfer of FeTMAPP to produce a well‐defined redox couple of FeIII/FeII at −0.291 and −0.314 V. Due to the synergic effect between RGO and the porphyrin, the nanocomposite showed excellent electrocatalytic activity toward the reduction of chlorite, thus leading to highly sensitive amperometric biosensing at low applied potential. The biosensor for chlorite showed a linear range from 5.0×10−8 to 1.2×10−4 mol L−1 with a detection limit of 2.4×10−8 mol L−1 at a signal‐to‐noise ratio of 3. The picket‐fence porphyrin could serve as an efficient species to functionalize graphene for electronic and optical applications.
On the Design of Fluorescent Ratiometric Nanosensors
Authors: Doussineau Tristan , Schulz Anja , Lapresta‐Fernandez Alejandro , Moro Artur , Körsten Susanne , Trupp Sabine , Mohr Gerhard J.
Published: July 2010

Advances in nanoparticle technology have recently offered new tools to the bioanalytical field of research. In particular, new nanoparticle‐based sensors have appeared able to give quantitative information about different species (ions, metabolites, biomolecules) in biosamples through ratiometric measurements. This article describes the methodologies developed so far in the design of such nanosensors. In particular, the different approaches to immobilize fluorescent chemosensor dyes to nanoparticles are presented. Concept designs of ratiometric nanosensors in terms of composition and architecture are also described and illustrated with examples taken from the literature.
Unifying Metal and Brønsted Acid Catalysis—Concepts, Mechanisms, and Classifications
Authors: Rueping Magnus , Koenigs Rene M. , Atodiresei Iuliana
Published: July 2010

Asymmetric catalysis is a key feature of modern synthetic organic chemistry. Traditionally, different combinations of ligands and metals are used to perform highly enantioselective reactions. Since the renaissance of organocatalysis in the early 2000s, tremendous improvement in the field of metal‐free catalysis has been achieved. Recently, the combination of transition metals and organocatalysts has allowed the development of new protocols enabling transformations that could not previously be realized. This article aims to present the latest contributions in the field of combined chiral Brønsted acid and metal catalyzed reactions, highlighting the advantages of these catalytic systems as well as describing the uncertainties regarding the molecular structure of the catalytically active species and the reaction mechanisms.
Enzymatic Synthesis of Enantiomerically Pure β‐Amino Ketones, β‐Amino Esters, and β‐Amino Alcohols with Baeyer–Villiger Monooxygenases
Authors: Rehdorf Jessica , Mihovilovic Marko D. , Fraaije Marco W. , Bornscheuer Uwe T.
Published: July 2010

The enzymatic kinetic resolution of a broad set of β‐amino ketones was investigated by using a collection of 16 Baeyer–Villiger monooxygenases from different bacterial origins, which display various substrate specificities. Within this platform of enzymes excellent enantioselectivities (E>200) were found towards aliphatic and aromatic 4‐amino‐2‐ketones, and some enzymes even showed opposite enantioselectivity. The intermediate β‐aminoalkyl acetates underwent autohydrolysis yielding optically pure β‐amino alcohols, which are key intermediates in the synthesis of natural products and bioactive compounds of high interest for the pharmaceutical industry. Furthermore, in some cases the abnormal esters were formed.
Background migration of USPIO/MLs is a major drawback for in situ labeling of endogenous neural progenitor cells
Authors: Vreys Ruth , Soenen Stefaan J. H. , De Cuyper Marcel , Van der Linden Annemie
Published: July 2010

MR‐labeling of endogenous neural progenitor cells (NPCs) to follow up cellular migration with in vivo magnetic resonance imaging (MRI) is a very promising tool in the rapidly growing field of cellular imaging. To date, most of the in situ labeling work has been performed using micron‐sized iron oxide particles. In this work magnetoliposomes (MLs), i.e. ultrasmall superparamagnetic iron oxide cores (USPIOs), each individually coated by a phospholipid bilayer, were used as the MR contrast agent. One of the main advantages of MLs is that the phospholipid bilayer allows easy modification of the surface, which creates the opportunity to construct a wide range of MLs optimized for specific biomedical applications. We have investigated the ability of MLs to label endogenous NPCs after direct injection into the adult mouse brain. Whereas MRI revealed contrast relocation towards the olfactory bulb, our data strongly imply that this relocation is independent of the migration of endogenous NPCs but represents background migration of MLs along a white matter tract. Our findings suggest that the small size of USPIOs/MLs intrinsically limits their potential for in situ labeling of NPCs. Copyright © 2010 John Wiley & Sons, Ltd.
Surrogate MR markers of response to chemo‐ or radiotherapy in association with co‐treatments: a retrospective analysis of multi‐modal studies
Authors: Jordan Bénédicte F. , Gallez Bernard
Published: July 2010

The study of magnetic resonance (MR) markers over the past decade has provided evidence that the tumor microenvironnement and hemodynamics play a major role in determining tumor response to therapy. The aim of the present work is to predict and monitor the efficacy of co‐treatments to radio‐ and chemotherapy by noninvasive MR imaging. Ten different co‐treatments were involved in this retrospective analysis of our previously published data, including NO‐mediated co‐treatments (insulin and isosorbide dinitrate), anti‐inflammatory drugs (hydrocortisone, NS‐398), anti‐angiogenic agents (thalidomide, SU5416 and ZD6474), a vasoactive agent (xanthinol nicotinate), botulinum toxin and carbogen breathing. Dynamic contrast enhanced (DCE) MRI, intrinsic susceptibility‐weighted (BOLD) MRI and electronic paramagnetic resonance (EPR) oximetry all reflect tumor microenvironment hemodynamic variables that are known to influence tumor response. Eight MR‐derived parameters (markers) were tested for their ability to predict therapeutic outcome (factor of increase in regrowth delay) in experimental tumor models (TLT and FSaII) after radiation therapy and/or chemotherapy with cyclophosphamide, namely tumor pO2 and O2 consumption rate (using EPR oximetry); tumor blood flow and permeability, i.e. V p, K trans, K ep and percentage of perfused vessels (using DCE‐MRI); and BOLD signal intensity and R 2* (using functional MRI). This multi‐modal comparison of co‐treatment efficacy points out the limitations of each MR marker and identifies in vivo pO2 as a relevant endpoint for radiation therapy. DCE parameters (V p and K ep) were identified as a relevant endpoints for cyclophosphamide chemotherapy in our tumor models. This study helps qualify relevant imaging endpoints in the preclinical setting of cancer therapy. Copyright © 2010 John Wiley & Sons, Ltd.
Quantitative 1H MRI, 19F MRI, and 19F MRS of cell‐internalized perfluorocarbon paramagnetic nanoparticles
Authors: Kok Maarten B. , de Vries Anke , Abdurrachim Desiree , Prompers Jeanine J. , Grüll Holger , Nicolay Klaas , Strijkers Gustav J.
Published: July 2010

In vivo molecular imaging with targeted MRI contrast agents will require sensitive methods to quantify local concentrations of contrast agent, enabling not only imaging‐based recognition of pathological biomarkers but also detection of changes in expression levels as a consequence of disease development, therapeutic interventions or recurrence of disease. In recent years, targeted paramagnetic perfluorocarbon emulsions have been frequently applied in this context, permitting high–resolution 1H MRI combined with quantitative 19F MR imaging or spectroscopy, under the assumption that the fluorine signal is not altered by the local tissue and cellular environment. In this in vitro study we have investigated the 19F MR–based quantification potential of a paramagnetic perfluorocarbon emulsion conjugated with RGD–peptide to target the cell–internalizing ανβ3–integrin expressed on endothelial cells, using a combination of 1H MRI, 19F MRI and 19F MRS. The cells took up the targeted emulsion to a greater extent than nontargeted emulsion. The targeted emulsion was internalized into large 1–7 µm diameter vesicles in the perinuclear region, whereas nontargeted emulsion ended up in 1–4 µm diameter vesicles, which were more evenly distributed in the cytoplasm. Association of the targeted emulsion with the cells resulted in different proton longitudinal relaxivity values, r1, for targeted and control nanoparticles, prohibiting unambiguous quantification of local contrast agent concentration. Upon cellular association, the fluorine R1 was constant with concentration, while the fluorine R2 increased nonlinearly with concentration. Even though the fluorine relaxation rate was not constant, the 19F MRI and 19F MRS signals for both targeted nanoparticles and controls were linear and quantifiable as function of nanoparticle concentration. Copyright © 2010 John Wiley & Sons, Ltd.
Theory of gradient coil design methods for magnetic resonance imaging
Authors: Hidalgo‐Tobon S.S.
Published: July 2010

The process to produce an MR image includes nuclear alignment, RF excitation, spatial encoding, and image formation. In simple terms, an magnetic resonance imaging (MRI) system consists of five major components: a magnet, gradient systems, an RF coil system, a receiver, and a computer system. To form an image, it is necessary to perform spatial localization of the MR signals, which is achieved using gradient coils. In modern MRI, gradient coils able to generate high gradient strengths and slew rates are required to produce high imaging speeds and improved image quality. MRI also requires the use of gradient coils that generate magnetic fields, which vary linearly with position over the imaging volume. Gradient coils for MRI must therefore have high current efficiency (defined as the ratio of gradient generated to current drawn), short switching time (i.e., low inductance), gradient linearity over a large volume, low power consumption, and minimal interaction with any other equipment, which would otherwise result in eddy currents. Over the last two decades new methods of gradient coil design have been developed, and a combination of these methods can be a mixture of them trying to avoid discomforts to patients that at the end is the center of all the technological efforts in the art of MRI. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 223–242, 2010.
Dipolar Halbach magnet stacks made from identically shaped permanent magnets for magnetic resonance
Authors: Soltner H. , Blümler P.
Published: July 2010

NMR Mandhalas (MagneticArrangement forNovelDiscreteHalbachLAyout) are arrays of identically shaped magnets in a Halbach‐type arrangement. They provide a simple and cost‐effective way to generate high magnetic fields for mobile applications, for example, in magnetic resonance. Based on the introductory publication by Raich and Blümler (Concepts Magn Reson 2004;23B:16–25), we extend the notion of Mandhalas from cube‐shaped magnets to polygonal and cylindrical ones and present construction guidelines for the stacking of such rings to generate homogeneous magnetic fields over larger volumes. For this purpose, we present formulas and numerical values based on a dipole approach to calculate the flux density of single rings and composed 3D systems and compare to corresponding results obtained by 3D boundary element method calculations. As an application of the approach presented here, we constructed prototypes. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 211–222, 2010.
Current patient management of chronic myeloid leukemia in Latin America
Authors: Cortes Jorge , De Souza Carmino , Ayala‐Sanchez Manuel , Bendit Israel , Best‐Aguilera Carlos , Enrico Alicia , Hamerschlak Nelson , Pagnano Katia , Pasquini Ricardo , Meillon Luis
Published: July 2010

BACKGROUND:

Treatment recommendations have been developed for management of patients with chronic myeloid leukemia (CML).

METHODS:

A 30‐item multiple‐choice questionnaire was administered to 435 hematologists and oncohematologists in 16 Latin American countries. Physicians self‐reported their diagnostic, therapeutic, and disease management strategies.

RESULTS:

Imatinib is available as initial therapy to 92% of physicians, and 42% of physicians have access to both second‐generation tyrosine kinase inhibitors. Standard‐dose imatinib is the preferred initial therapy for most patients, but 20% would manage a young patient initially with an allogeneic stem cell transplant from a sibling donor, and 10% would only offer hydroxyurea to an elderly patient. Seventy‐two percent of responders perform routine cytogenetic analysis for monitoring patients on therapy, and 59% routinely use quantitative polymerase chain reaction. For patients who fail imatinib therapy, 61% would increase the dose of imatinib before considering change to a second‐generation tyrosine kinase inhibitor, except for patients aged 60 years, for whom a switch to a second‐generation tyrosine kinase inhibitor was the preferred choice.

CONCLUSIONS:

The answers to this survey provide insight into the management of patients with CML in Latin America. Some deviations from current recommendations were identified. Understanding the treatment patterns of patients with CML in broad population studies is important to identify needs and improve patient care. Cancer 2010. © 2010 American Cancer Society.
Clinical impact of tumor‐infiltrating lymphocytes for survival in stage II colon cancer
Authors: Lee Won‐Suk , Park Sanghui , Lee Woo Yong , Yun Seong Hyeon , Chun Ho‐Kyung
Published: July 2010

BACKGROUND:

The most reliable prognostic factor in colon cancer is the TNM classification. The objective of this study was to assess and compare the prognostic role of tumor‐infiltrating lymphocytes (TILs) in stage II colon cancer.

METHODS:

Immunohistochemistry was used to assess the density of TILs that were positive for cluster of differentiation 3 (CD3) (T‐cell coreceptor), CD45 isoform RO (CD45RO) (protein tyrosine phosphatase), nuclear transcription factor forkhead box P3 (FOXP3), and CD25 (a type I transmembrane protein) according to tumor site (intraepithelial and stromal) in samples from 87 patients who had stage II colon cancer. These variables were evaluated for their association with histopathologic features along with overall survival (OS) and disease‐free survival (DFS).

RESULTS:

Intraepithelial CD3‐posititve (CD3+), CD45RO+, CD25+, and FOXP3+ TILs were associated significantly with better DFS (P = .049, P = .009, P = .013, and P = .001, respectively). The estimated 5‐year OS rates for patients who had high‐density CD45RO+ and FOXP3+ expression was 100% for both compared with 79.2% and 78.8% for patients who had low‐density CD45RO+ and FOXP3+ expression (P = .017 and P = .040, respectively). A significant prognostic factor for both OS and DFS was high‐density stromal CD45RO+ lymphocytic infiltration (OS: P = .031; relative risk [RR], 0.134; 95% confidence interval [CI], 0.015‐1.164; DFS: P = .013; RR, 0.198; 95% CI, 0.055‐0.710); whereas intraepithelial FOXP3+ expression was an independent prognostic factor for DFS (P = .032; RR, 0.108; 95% CI, 0.014‐0.821).

CONCLUSIONS:

FOXP3+ and CD45RO+ TILs demonstrated independent prognostic significance for survival in the current investigation. These results may help to improve the prognostication of early stage colon cancer. Cancer 2010. © 2010 American Cancer Society.
Pretransplantation [18‐F]fluorodeoxyglucose positron emission tomography scan predicts outcome in patients with recurrent Hodgkin lymphoma or aggressive non‐Hodgkin lymphoma undergoing reduced‐intensity conditioning followed by allogeneic stem cell transplantation
Authors: Dodero Anna , Crocchiolo Roberto , Patriarca Francesca , Miceli Rosalba , Castagna Luca , Ciceri Fabio , Bramanti Stefania , Frungillo Niccolo , Milani Raffaella , Crippa Flavio , Fallanca Federico , Englaro Emanuela , Corradini Paolo
Published: July 2010

BACKGROUND:

The use of positron emission tomography (PET) scanning in Hodgkin lymphoma (HL) and aggressive non‐Hodgkin lymphoma (HG‐NHL) has recognized prognostic value in patients who are receiving chemotherapy or undergoing autologous stem cell transplantation (SCT). In contrast, the role of PET before reduced‐intensity conditioning (RIC) and followed by allogeneic SCT has not been investigated to date.

METHODS:

PET was used to assess 80 patients who had chemosensitive disease (34 patients with HG‐NHL and 46 patients with HL) before they underwent allogeneic SCT: 42 patients had negative PET studies, and 38 patients had positive PET studies. Patients underwent allograft from matched related siblings (n = 41) or alternative donors (n = 39).

RESULTS:

At the time of the last follow‐up, 48 patients were alive (60%), and 32 had died. The 3‐year cumulative incidence of nonrecurrence mortality and disease recurrence was 17% and 40%, respectively. The cumulative incidence of disease recurrence was significantly lower in the PET‐negative patients (25% vs 56%; P = .007), but there was no significant difference between the patients with or without chronic graft‐versus‐host disease (P = .400). The patients who had negative PET studies before undergoing allogenic SCT also had significantly better outcomes in terms of 3‐year overall survival (76% vs 33%; P = .001) and 3‐year progression‐free survival (73% vs 31%; P = .001). On multivariate analysis, overall survival was influenced by PET status (hazard ratio [HR], 3.35), performance status (HR, 5.15), and type of donor (HR, 6.26 for haploidentical vs sibling; HR, 1.94 for matched unrelated donor vs sibling).

CONCLUSIONS:

The current results indicated that PET scanning appears to be an accurate tool for assessing prognosis in patients who are eligible for RIC allografting. Cancer 2010. © 2010 American Cancer Society.
Vascular endothelial growth factor‐targeted therapy for the treatment of adult metastatic Xp11.2 translocation renal cell carcinoma
Authors: Choueiri Toni K. , Lim Zita Dubauskas , Hirsch Michelle S. , Tamboli Pheroze , Jonasch Eric , McDermott David F. , Cin Paola Dal , Corn Paul , Vaishampayan Ulka , Heng Daniel Y.C. , Tannir Nizar M.
Published: July 2010

BACKGROUND:

Adult “translocation” renal cell carcinoma (RCC), bearing transcription factor E3 (TFE3) gene fusions at Xp11.2, is a recently recognized, unique entity for which prognosis and therapy remain poorly understood. In the current study, the authors investigated the effect of vascular endothelial growth factor (VEGF)‐targeted therapy in this distinct subtype of RCC.

METHODS:

A retrospective review was conducted to describe the clinical characteristics and outcome of adult patients with metastatic Xp11.2 RCC who had strong TFE3 nuclear immunostaining and received anti‐VEGF therapy. Tumor response to anti‐VEGF therapy was evaluated using Response Evaluation Criteria in Solid Tumors (RECIST) criteria. The Kaplan‐Meier method was used to estimate progression‐free survival (PFS) and overall survival (OS) distributions.

RESULTS:

Fifteen patients were identified, of whom 10, 3, and 2 received sunitinib, sorafenib, and monoclonal anti‐VEGF antibodies, respectively. The median follow‐up was 19.1 months, the median age of the patients was 41 years, and the female:male ratio was 4:1. Initial histologic description included clear cell (n = 8 patients), papillary (n = 1 patient), or mixed clear cell/papillary RCC (n = 6 patients). Five patients had received prior systemic therapy. Five patients had undergone fluorescent in situ hybridization analysis and all demonstrated a translocation involving chromosome Xp11.2. When treated with VEGF‐targeted therapy, 3 patients achieved a partial response, 7 patients had stable disease, and 5 patients developed progressive disease. The median PFS and OS of the entire cohort were 7.1 months and 14.3 months, respectively.

CONCLUSIONS:

Adult‐onset, translocation‐associated metastatic RCC is an aggressive disease that affects a younger population of patients with a female predominance. In the current study, VEGF‐targeted agents appeared to demonstrate some efficacy. Cancer 2010. © 2010 American Cancer Society.