bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular prenatal diagnosis: the impact of modern technologies
Authors: Lucy Raymond F. , Whittaker Joanne , Jenkins Lucy , Lench Nick , Chitty Lyn S.
Published: June 2010

Originally prenatal diagnosis was confined to the diagnosis of metabolic disorders and depended on assaying enzyme levels in amniotic fluid. With the development of recombinant DNA technology, molecular diagnosis became possible for some genetic conditions late in the 1970s. Here we briefly review the history of molecular prenatal diagnostic testing, using Duchenne muscular dystrophy as an example, and describe how over the last 30 years we have moved from offering testing to a few affected individuals using techniques, such as Southern blotting to identify deletions, to more rapid and accurate PCR‐based testing which identifies the precise change in dystrophin for a greater number of families. We discuss the potential for safer, earlier prenatal genetic diagnosis using cell free fetal DNA in maternal blood before concluding by speculating on how more recent techniques, such as next generation sequencing, might further impact on the potential for molecular prenatal testing. Progress is not without its challenges, and as cytogenetics and molecular genetics begin to unite into one, we foresee the main challenge will not be in identifying the genetic change, but rather in interpreting its significance, particularly in the prenatal setting where we frequently have no phenotype on which to base interpretation. Copyright © 2010 John Wiley & Sons, Ltd.
Current status of oriental medicine in treating Korean allergy patients
Authors: Shin Yoo Seob , Park Jung‐Won , Lee Yong‐Won , Kim Cheol‐Woo , Dhong Hun‐Jong , Park Hae‐Sim , Cho Young‐Joo , Cho Sang‐Heon , Pyun Bok Yang , Lee Kwang Hoon. , Lee Hae Ran , Hong Chein‐Soo
Published: June 2010

Purpose

To evaluate the prevalence, compliance, pattern of use, and economic cost of OM in Korean allergy patients.

Methods

A total of 647 allergy patients were enrolled from 10 general hospitals, and were surveyed by the questionnaire. It consisted of 12 items and regarded the prescription rates, reasons for referring, their opinions for the efficacy of OM, and economic costs.

Results

A total of 259 (40.5%) patients had used OM, and 35.5% of these patients experienced two or more kinds of these practices. A patients' income or education level did not affect the prescription rates of OM. Of the patients that used OM, 34.6% of them were satisfied with the effect of OM treatment, and 40.9% of them were inclined to continue with their OM treatments. The most frequent reasons for choosing OM were the patient's belief that OM can predispose ‘allergic constitution to normal’ (30.2%), worries about the possible adverse reactions of the long‐term administration of the proven drugs (20.2%), and the safety of OM (15.6%). However, 18.9% of these patients experienced perceived adverse events to their OM treatment such as skin rashes, gastrointestinal discomfort, and hepatitis. The patients that have used OM spent on average $915 US dollars annually for OM treatment.

Conclusions

Many Korean allergy patients are cliental to OM. Some patients experienced a satisfactory treatment effect from OM, however, others had no treatment effect, even adverse event. Therefore, it is important to educate people to use OM appropriately to make harmony with modern medicine. Copyright © 2010 John Wiley & Sons, Ltd.
Statin use and depressive symptoms in a prospective study of community‐living older persons
Authors: Feng Liang , Yap Keng Bee , Kua Ee Heok , Ng Tze Pin
Published: June 2010

PURPOSE

The association between statin use and depression is complex, and research findings have been mixed. The present study aimed to investigate the association of statin use with depressive symptoms among community‐living older persons, and its effect modifications by gender and medical co‐morbidity.

METHOD

Prospective observational study of 1803 participants aged 55 and above in the Singapore Longitudinal Ageing Studies cohort, with data of statin use and other risk factors for depression at baseline, and Geriatric Depression Scale (GDS) symptom scores at follow‐up (1.5 years).

RESULTS

Controlling for baseline demographics, cholesterol level and medical co‐morbidities, statin use was not associated with depressive symptom scores in the whole sample overall (regression coefficient = −0.12 (SE 0.10), F[1,1782] = 1.44, p = 0.23). Post hoc analyses suggested that statin use may be associated with fewer depressive symptoms in women (p = 0.02), and more depressive symptoms in men, particularly those with more medical co‐morbidities (p = 0.04) and multiple drug use (p = 0.02).

CONCLUSION

This study provided no strong evidence that support an overall association of statin use and depressive symptoms. The post hoc findings in this study are suggestive but may also be spurious and should be replicated in other studies. Copyright © 2010 John Wiley & Sons, Ltd.
Uncoupling of bait‐protein expression from the prey protein environment adds versatility for cell and tissue interaction proteomics and reveals a complex of CARP‐1 and the PKA Cβ1 subunit
Authors: Erlbruch Andrea , Hung Chien‐Wen , Seidler Joerg , Borrmann Katrin , Gesellchen Frank , König Norbert , Kübler Dieter , Herberg Friedrich W. , Lehmann Wolf D. , Bossemeyer Dirk
Published: June 2010

An expression‐uncoupled tandem affinity purification assay is introduced which differs from the standard TAP assay by uncoupling the expression of the TAP‐bait protein from the target cells. Here, the TAP‐tagged bait protein is expressed in Escherichia coli and purified. The two concatenated purification steps of the classical TAP are performed after addition of the purified bait to brain tissue homogenates, cell and nuclear extracts. Without prior genetic manipulation of the target, upscaling, free choice of cell compartments and avoidance of expression triggered heat shock responses could be achieved in one go. By the strategy of separating bait expression from the prey protein environment numerous established, mostly tissue‐specific binding partners of the protein kinase A catalytic subunit Cβ1 were identified, including interactions in binary, ternary and quaternary complexes. In addition, the previously unknown small molecule inhibitor‐dependent interaction of Cβ1 with the cell cycle and apoptosis regulatory protein‐1 was verified. The uncoupled tandem affinity purification procedure presented here expands the application range of the in vivo TAP assay and may serve as a simple strategy for identifying cell‐ and tissue‐specific protein complexes.
Building Pragmatist Theories of PM Practice: Theorizing the Act of Project Management
Authors: Lalonde Pierre-Luc , Bourgault Mario , Findeli Alain
Published: June 2010

This article examines project management through the lens of practice. Drawing on the literature, we develop a typological model that brings together four distinct theoretical types of project management practice. Adopting a deliberately critical perspective, we show that the first three types propose a weak conception of the logical relationship between the theory and practice of project management. In contrast, the fourth type, anchored in a pragmatist conception of the theory-practice link, provides the potential to build strong theories of project management practice. A specific objective is to elucidate the distinct features of the fourth type of theory.
Demystifying the Folklore of the Accidental Project Manager in the Public Sector
Authors: Darrell Vanessa , Baccarini David , Love Peter E. D.
Published: June 2010

Many individuals are called upon to undertake project management responsibilities with little or no preparation. Such project managers have been referred to as accidental project managers. This article examines the experiences of 46 accidental project managers within the Western Australian public sector through a questionnaire survey. Findings reveal that most project managers were selected based on their technical or managerial expertise and thus lacked the required competencies to deliver a project. There was a greater propensity for accidental project managers to act in a part-time mode, undertake nontechnical projects, and be provided with limited training and education.
Tunnelling corrections in hydrogen abstractions by excited‐state ketones
Authors: Barroso Monica , Arnaut Luis G. , Formosinho Sebastião J.
Published: June 2010

Hydrogen abstraction from 1‐phenylethanol by triplet acetophenone occurs from both CH and OH bonds. The reaction path of the Interacting‐State Model (ISM) is used with the Transition‐State Theory (TST) and the semiclassical correction for tunnelling (ISM/scTST) to help rationalizing the experimental kinetic results and elucidate the mechanisms of these reactions. The weak exothermicity of the abstraction from the strong OH bond is compensated by electronic effects, hydrogen bonding and tunnelling, and is competitive with the more exothermic abstraction from the α‐CH bond of 1‐phenylethanol. The alkoxy radical formed upon abstraction from OH reacts within the solvent cage and the primary product of this reaction is 1‐phenylethenol. The corresponding kinetic isotope effect is ca. 3 and is entirely consistent with a tunnelling correction ca. 9 for H abstraction. We therefore demonstrate that the tunnelling correction is the major contributor to the kinetic isotope effect. Copyright © 2010 John Wiley & Sons, Ltd.
Theoretical aspects of tunneling proton transfer reactions in a polar environment
Authors: Kiefer Philip M. , Hynes James T.
Published: June 2010

This paper reviews some nontraditional theoretical views developed in this group on acid–base proton transfer (PT) reactions in hydrogen (H‐) bonded systems, focusing on the tunneling regime. Key ingredients in this picture are a completely quantum character for the proton motion (even when tunneling does not occur), the identification of a solvent coordinate as the reaction coordinate, and attention to the H‐bond vibrational ‘promoting’ mode in the acid–base complex. Attention is also given to the electronic structure rearrangements associated with PT in the electronically adiabatic regime. A general overview is presented for the tunneling rate constants including the activation free energy and the associated primary kinetic isotope effects (KIEs) for proton tunneling reactions. Copyright © 2010 John Wiley & Sons, Ltd.
A pictorial representation of zero‐point energy and tunnelling contributions to primary hydrogen isotope effects
Authors: O'Ferrall R. A. More
Published: June 2010

The interpretation of primary hydrogen isotope effects in terms of isotopic sensitivities of zero‐point energies in the reactants and transition state is reviewed. The reader is reminded that the transition state for a hydrogen transfer reaction corresponds to the position of maximum energy on the minimum energy path defined by the motion of the heavy atoms between which hydrogen is transferred. Tunnelling occurs through the potential energy barrier separating the reactant and product channels of the potential energy surface for this reaction. It is a consequence of rapid vibrational motion of the hydrogen within a collision complex and the overlap of vibrational wave functions between reactant and product sides of the barrier. Comparing zero‐point energies of a tunnelling complex and a hydrogen bond confirms results of calculations indicating that the zero‐point energy of the complex is likely to be less than that of the reactants. It follows that there should be a compensation between contributions from zero‐point energy changes and tunnelling which may explain why tunnelling rarely leads to very large isotope effects at ambient temperatures. The isotopic sensitivity of the zero‐point energy of the transition state is discussed in terms of variations in force constants of reacting bonds within a three‐centre model. A shift in isotopic sensitivity from the reaction coordinate mode to real stretching vibration as the structure of the transition state becomes more reactant‐ or product‐like, which provides a basis for the Westheimer effect, contrasts with the behaviour of hydrogen bonds, for which there is no change in isotopic sensitivity of the two stretching modes. Copyright © 2010 John Wiley & Sons, Ltd.
The structure and evolution of the murine inhibitor of carbonic anhydrase: A member of the transferrin superfamily
Authors: Eckenroth Brian E. , Mason Anne B. , McDevitt Meghan E. , Lambert Lisa A. , Everse Stephen J.
Published: June 2010

The original signature of the transferrin (TF) family of proteins was the ability to bind ferric iron with high affinity in the cleft of each of two homologous lobes. However, in recent years, new family members that do not bind iron have been discovered. One new member is the inhibitor of carbonic anhydrase (ICA), which as its name indicates, binds to and strongly inhibits certain isoforms of carbonic anhydrase. Recently, mouse ICA has been expressed as a recombinant protein in a mammalian cell system. Here, we describe the 2.4 Å structure of mouse ICA from a pseudomerohedral twinned crystal. As predicted, the structure is bilobal, comprised of two α‐β domains per lobe typical of the other family members. As with all but insect TFs, the structure includes the unusual reverse γ‐turn in each lobe. The structure is consistent with the fact that introduction of two mutations in the N‐lobe of murine ICA (mICA) (W124R and S188Y) allowed it to bind iron with high affinity. Unexpectedly, both lobes of the mICA were found in the closed conformation usually associated with presence of iron in the cleft, and making the structure most similar to diferric pig TF. Two new ICA family members (guinea pig and horse) were identified from genomic sequences and used in evolutionary comparisons. Additionally, a comparison of selection pressure (dN/dS) on functional residues reveals some interesting insights into the evolution of the TF family including that the N‐lobe of lactoferrin may be in the process of eliminating its iron binding function.
Probing local structural fluctuations in myoglobin by size‐dependent thiol‐disulfide exchange
Authors: Stratton Margaret M. , Cutler Thomas A. , Ha Jeung‐Hoi , Loh Stewart N.
Published: June 2010

All proteins undergo local structural fluctuations (LSFs) or breathing motions. These motions are likely to be important for function but are poorly understood. LSFs were initially defined by amide hydrogen exchange (HX) experiments as opening events, which expose a small number of backbone amides to 1H/2H exchange, but whose exchange rates are independent of denaturant concentration. Here, we use size‐dependent thiol‐disulfide exchange (SX) to characterize LSFs in single cysteine‐containing variants of myoglobin (Mb). SX complements HX by providing information on motions that disrupt side chain packing interactions. Most importantly, probe reagents of different sizes and chemical properties can be used to characterize the size of structural opening events and the properties of the open state. We use thiosulfonate reagents (126–274 Da) to survey access to Cys residues, which are buried at specific helical packing interfaces in Mb. In each case, the free energy of opening increases linearly with the radius of gyration of the probe reagent. The slope and the intercept are interpreted to yield information on the size of the opening events that expose the buried thiol groups. The slope parameter varies by over 10‐fold among Cys positions tested, suggesting that the sizes of breathing motions vary substantially throughout the protein. Our results provide insight to the longstanding question: how rigid or flexible are proteins in their native states?
Developmental expression of human hemoglobins mediated by maturation of their subunit interfaces
Authors: Manning Lois R. , Popowicz Anthony M. , Padovan Julio , Chait Brian T. , Russell J. Eric , Manning James M.
Published: June 2010

Different types of human hemoglobins (Hbs) consisting of various combinations of the embryonic, fetal, and adult Hb subunits are present at certain times during development representing a major paradigm of developmental biology that is still not understood and one which we address here. We show that the subunit interfaces of these Hbs have increasing bonding strengths as demonstrated by their distinct distribution of tetramers, dimers, and monomers during gel filtration at very low‐Hb concentration. This maturation is mediated by competition between subunits for more favorable partners with stronger subunit interactions. Thus, the protein products of gene expression can themselves have a role in the developmental process due to their intrinsic properties.
Topology of the disulfide bonds in the antiviral lectin scytovirin
Authors: Moulaei Tinoush , Stuchlik Olga , Reed Matthew , Yuan Weirong , Pohl Jan , Lu Wuyuan , Haugh‐Krumpe Lauren , O'Keefe Barry R. , Wlodawer Alexander
Published: June 2010

The antiviral lectin scytovirin (SVN) contains a total of five disulfide bonds in two structurally similar domains. Previous reports provided contradictory results on the disulfide pairing in each individual domain, and we have now re‐examined the disulfide topology. N‐terminal sequencing and mass spectrometry were used to analyze proteolytic fragments of native SVN obtained at acidic pH, yielding the assignment as Cys7–Cys55, Cys20–Cys32, Cys26–Cys38, Cys68–Cys80, and Cys74–Cys86. We also analyzed the N‐terminal domain of SVN (SD1, residues 1–48) prepared by expression/oxidative folding of the recombinant protein and by chemical synthesis. The disulfide pairing in the chemically synthesized SD1 was forced into predetermined topologies: SD1A (Cys20–Cys26, Cys32–Cys38) or SD1B (Cys20–Cys32, Cys26–Cys38). The topology of native SVN was found to be in agreement with the SD1B and the one determined for the recombinant SD1 domain. Although the two synthetic forms of SD1 were distinct when subjected to chromatography, their antiviral properties were indistinguishable, having low nM activity against HIV. Tryptic fragments, the “cystine clusters” [Cys20–Cys32/Cys26–Cys38; SD1] and [Cys68–Cys80/Cys74–C‐86; SD2], were found to undergo rapid disulfide interchange at pH 8. This interchange resulted in accumulation of artifactual fragments in alkaline pH digests that are structurally unrelated to the original topology, providing a rational explanation for the differences between the topology reported herein and the one reported earlier (Bokesh et al., Biochemistry 2003;42:2578–2584). Our observations emphasize the fact that proteins such as SVN, with disulfide bonds in close proximity, require considerable precautions when being fragmented for the purpose of disulfide assignment.
Ghrelin improves disturbed myocardial energy metabolism in rats with heart failure induced by isoproterenol
Authors: Xu Jian‐Ping , Wang Hong‐Xia , Wang Wen , Zhang Li‐Ke , Tang Chao‐Shu
Published: June 2010

To explore the effects of ghrelin on disturbed myocardial energy metabolism during chronic heart failure (CHF). Rats were subcutaneously injected with isoproterenol (ISO) for 10 days with or without ghrelin for another 10 days. Enzyme immunoassay was to measure ghrelin concentrations. Compared with the control group, ISO‐treated rats showed suppressed cardiac function with high ghrelin/GHS‐R expressions. These rats also showed the decreases in food consumption and weight. The decreased levels of plasma glucose and myocardial glucogen, but the high lactate in blood and myocardium showed myocardial metabolic disturbance. Compared with the group given ISO alone, the rats with ghrelin (20 and 100 µg/kg/day) improved cardiac dysfunction and increased food intake by 13.5 and 14.2% (both P < 0.01), and rate of weight gain by 95% (P < 0.05) and 1.71‐fold (P < 0.01), respectively. The plasma glucose were increased by 49.7 and 50.8% (both P < 0.01), and myocardial glucogen, by 40.5 and 51.7% (both P < 0.01), but blood lactate decreased by 1.56‐ and 1.96‐fold (both P < 0.01), and myocardial lactate by 32.1 and 48.7% (both P < 0.05), respectively. Their MCT1 mRNA and protein expressions increased. The myocardial ghrelin/GHS‐R pathway can be upregulated during CHF. The ghrelin can attenuate cardiac dysfunction and energy metabolic disturbance in CHF rats. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
NMR‐based detection of acetylation sites in peptides
Authors: Smet‐Nocca Caroline , Wieruszeski Jean‐Michel , Melnyk Oleg , Benecke Arndt
Published: June 2010

Acetylation of histone tails as well as non‐histone proteins was found to be a major component of the ‘chromatin code’ that regulates transcription through the recruitment of transcription factors, co‐regulators and DNA‐binding proteins. Acetylation can have several effects modifying protein–protein interactions, protein activity, localization and stability. Using NMR spectroscopy, we provide a simple way to detect acetyl moieties at the ε‐amino function of lysine residues based on peptides derived from Histone H4 and TDG amino‐terminal domains. Significant changes of acetyl‐lysine resonances as compared to non‐acetylated residues allow a direct identification of specific acetylated lysine. We also show that, in unfolded peptides, acetylation of lysine side chains leads to characteristic NMR signals that vary only weakly depending on the primary sequence or the total number of acetylated sites, indicating that the acetamide group does not establish any interactions with other residues. Furthermore, resonance changes upon acetylation are restricted to residues nearby the acetylation site, indicating that acetylation does not modify the overall peptide conformation. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Preferred conformation of peptides rich in Ac8c, a medium‐ring alicyclic Cα,α‐disubstituted glycine
Authors: Moretto Vittorio , Formaggio Fernando , Crisma Marco , Bonora Gian Maria , Toniolo Claudio , Benedetti Ettore , Santini Antonello , Saviano Michele , Di Blasio Benedetto , Pedone Carlo
Published: June 2010

A complete series of terminally blocked, monodispersed homo‐oligopeptides (to the pentamer level) from the sterically demanding, medium‐ring alicyclic Cα,α‐disubstituted glycine 1‐aminocyclooctane‐1‐carb oxylic acid (Ac8c), and two Ala/Ac8c tripeptides, were synthesized by solution methods and fully characterized. The preferred conformation of all the oligopeptides was determined in deuterochloroform solution by IR absorption and 1H‐NMR. The molecular structures of the amino acid derivative Z‐Ac8c‐OH, the dipeptide pBrBz‐ (Ac8c)2‐OH and the tripeptide pBrBz‐(Ac8c)3‐OtBu were assessed in the crystal state by X‐ray diffraction. Conformational energy computations were performed on the monopeptide Ac‐Ac8c‐NHMe. Taken together, the results obtained strongly support the view that the Ac8c residue is an effective β‐turn and helix former. A comparison is also made with the conformational preferences of α‐aminoisobutyric acid, the prototype of Cα, α‐disubstituted glycines, and of the other members of the family of 1‐aminocycloalkane‐1‐carboxylic acids (Acnc, with n=3, 5–7) investigated so far. The implications for the use of the Ac8c residue in peptide conformational design are considered.
Elucidation of the structure of constrained bicyclopeptides in solution by two‐dimensional cross‐relaxation spectroscopy: Amatoxin analogues
Authors: Isernia Carla , Falcigno Lucia , Macura Slobodan , Paolillo Livio , Pastore Anna Lisa , Zanotti Giancarlo
Published: June 2010

The evaluation of peptide structures in solution is made feasible by the combined use of two‐dimensional NMR in the laboratory (NOESY) and rotating frames (ROESY), and by the use of molecular dynamics calculations. The present paper describes how both the NMR method and molecular dynamics calculations were applied to very rigid synthetic bicyclic peptides that are analogues of natural amatoxins. The NMR theory, which allows the estimate of interatomic distances between interacting nuclei, is briefly discussed. The experimental data were compared with those of known solid‐state structures. Three amatoxin analogues have been examined. Of these, one is biologically active (S‐deoxo γ[R] OH‐Ile3‐amaninamide) and its structure in the solid state has recently been worked out. The second and third analogues (S‐deoxo‐Ile3 ‐Ala5‐amaninamide and S‐deoxo‐D‐Ile3 ‐amaninamide, respectively) are inactive and their solid‐state structures are unknown. The data presented confirm the authors' previous hypothesis that lack of biological activity of S‐deoxo‐Ile3‐Ala5‐ amaninamide is due to the masking of the tryptophan ring by the methyl group of L‐Ala and not to massive conformational changes of the analogue.
Solution synthesis of human midkine, a novel heparin‐binding neurotrophic factor consisting of 121 amino acid residues with five disulphide bonds
Authors: Inui Tatsuya , Bódi József , Kubo Shigeru , Nishio Hideki , Kimura Terutoshi , Kojima Soichi , Maruta Hiroshi , Muramatsu Takashi , Sakakibara Shumpei
Published: June 2010

Human midkine (hMK), a novel heparin‐binding neurotrophic factor consisting of 121 amino acid residues with five intramolecular disulphide bonds, was synthesized by solution procedure in order to demonstrate the usefulness of our newly developed solvent system, a mixture of dichloromethane or chloroform and trifluoroethanol. The final protected 121‐residue peptide was assembled from two large fully protected intermediates, Boc‐(1–5 9)‐OH and H‐(60–121)‐OBzl, in CHL/TFE (3:1, v/v) using water‐soluble carbodiimide in the presence of HOOBt as coupling reagents. After removal of the protecting groups by HF followed by treatment with Hg(OAc)2 in 50% acetic acid, the fully deprotected peptide was subjected to the oxidative folding reaction. The final product was confirmed to have the correct disulphide structure from its tryptic peptide mapping and to possess the same biological activities as those of the natural product. In order to clarify the active region of the hMK molecule, the N‐terminal and C‐terminal half domains [(1–59) and (60–121)] were also synthesized by the same procedure used for the hMK synthesis. The C‐half domain was confirmed to show the full pattern of bioactivities except for the neuronal cell survival activity, while the N‐half one showed much less activity in general.
Segregation, quantum confinement effect and band offset for [110] SiGe NWs
Authors: Amato Michele , Palummo Maurizia , Ossicini Stefano
Published: June 2010

Results of first‐principles DFT simulations provide strong evidence that, at zero temperature, for [110] oriented SiGe nanowires (NWs), the segregated structure is favoured with respect to the mixed ones; for this observation two different schemes of calculations are presented and discussed. Moreover the segregation strongly influences the NWs electronic properties, inducing a reduced quantum confined effect (RQCE). We show here that it depends on the effect of strain in the plane normal to the direction of growth and not on the choice of lattice parameter in the direction of growth. A qualitative evaluation of the band offset between Si and Ge for SiGe NWs is also presented.
AFM and SNOM characterization of ordinary chondrites: A contribution to solving the problem of asteroid reddening
Authors: Pompeo Giuliano , Longo Giovanni , Girasole Marco , Moretti Pierfrancesco , Palomba Ernesto , Maras Adriana , Somma Fabrizia , Cricenti Antonio
Published: June 2010

Space weathering (SW) is an ensemble of processes that act on a body exposed to the space environment. Typically, the exposure to SW results in the accumulation, at the surface, of nanoparticles, that are thought to be produced through a vaporization and subsequent cooling of the metallo‐silicaceous components exposed to the space environment. The presence of such nanoparticles is responsible for the so‐called reddening of the asteroids' reflectance spectra (i.e., the increase in Vis–NIR reflectance with increase in wavelength) observed by remote‐sensing measurements. To investigate the mechanism of formation of these nanoparticles, we have employed atomic force microscopy (AFM) and scanning near‐field optical microscopy (SNOM) to morphologically and optically characterize ordinary chondrites (OC), the most abundant class of meteorites collected on Earth and whose parent bodies are the S‐type asteroids. The AFM study reveals the occurrence of a diffuse nanophase (martensite) in the meteorite's metal inclusions. Since the same areas show a reddening of the reflectivity spectra, this suggests that such spectral modification is based on a shock‐induced phase transformation of the metal components of the extraterrestrial body. To gain more insight into this nanophase and on its role in the SW of the asteroids, an optical characterization by SNOM has been performed on OCs. In this work we exploited the peculiarity of this technique to search for a correlation between the topography on the nanoscale and the spectral characteristics, at different wavelengths in the red‐NIR range, of the observed nanophase. Indeed, a high‐resolution mapping of the optical properties of the meteorite provides an interesting method to discriminate between martensite‐based and Fe‐silicaceous nanoparticles.
Spectroscopic ellipsometry of SrTiO3 crystals applied to antiferrodistortive surface phase transition
Authors: Dejneka Alexandr , Trepakov Vladimir , Jastrabik Lubomir
Published: June 2010

This work is devoted to the ellipsometric study of antiferrodistortive (AFD) $O_{h}^{1} $ → $D_{4h}^{18} $ cubic‐to‐tetragonal phase transition (PT) of SrTiO3 surface. Strong influence of surface defect structure on magnitude and temperature evolutions of surface refractive index related to PT was found and investigated. It is shown that even small surface imperfections result in enhancement and strong changes of the surface refractive index when approaching the temperature of PT. This effect is caused by emergence and evolutions in the surface of the structural changes corresponding to order parameter at the temperatures sufficiently higher than transition temperature in the bulk. In the case of structurally perfect crystal surface, the features of the temperature dependence of surface refractive index appeared to be very small and visible at the temperatures a little smaller than transition temperature for bulk that agrees well with predictions of Kaganov–Omel'yanchuk theory.
Excitonic effects in the nonlinear optical response of a Si(111) surface
Authors: Stamova Maria , Rebentrost Frank
Published: June 2010

We discuss methods to calculate the linear and nonlinear optical spectra for cyclic cluster models of an ideal Si(111) surface. The cluster approach offers the possibility to implement the excitonic effects due to the Coulomb interaction between electron and hole in a relatively straight‐forward way. In order to appproximate a situation resembling a surface we use clusters with several hundreds of Si atoms. The electronic structure is obtained from a tight‐binding parametrization of the hamiltonian. A time‐dependent density operator formalism is used to calculate the response functions $S(\tau )$ and $S(\tau _{1} ,\tau _{2} )$ for the optical polarization, which also directly describe the response to ultrashort pulses. Their Fourier transforms are the frequency‐dependent optical susceptibilities $\chi {}^{(1)} ( - \omega ;\omega )$ and $\chi {}^{(2)} ( - \omega _{1} - \omega _{2} ;\omega _{1} ,\omega _{2} )$ for second‐harmonic ($\omega _{1} = \omega _{2} $) or sum‐frequency generation from surfaces. The excitonic Coulomb interaction is treated in the time‐dependent Hartree–Fock approximation, leading to large sets of differential equations that are integrated explicitly. The results on the linear susceptibility are in accord with earlier findings on the excitonic origin of the relative intensities of the E1 and E2 peaks near 3.4 and 4.3 eV. We present new results on excitonic effects in the nonlinear spectra and investigate in particular the surface‐related peaks near 2$\hbar \omega $ = 1.3–1.5 and 2.4 eV that govern the strong enhancement observed in SHG of clean silicon surfaces.
Metal–insulator transition in Si(111)‐(4 × 1)/(8 × 2)‐In studied by optical spectroscopy
Authors: Speiser E. , Chandola S. , Hinrichs K. , Gensch M. , Cobet C. , Wippermann S. , Schmidt W.G. , Bechstedt F. , Richter W. , Fleischer K. , McGilp J. F. , Esser N.
Published: June 2010

Measurements of the surface vibrational modes and optical response of Si(111)‐(4 × 1)/(8 × 2)‐In are compiled and a comparison to ab initio calculations performed within DFT‐LDA formalism is given. Surface resonant Raman spectroscopy allows identifying a number of surface phonons with high spectral precision. The phase transition of the (4 × 1)–(8 × 2) surface structure is found to be accompanied by characteristic changes of the surface phonons, which are discussed with respect to various structural models suggested. The optical anisotropy of the (8 × 2) phase shows that the anisotropic Drude tail of the (4 × 1) phase is replaced by two peaks at 0.50 and 0.72 eV. The spectroscopic signatures of the (4 × 1) and (8 × 2) phases agree with a metal–insulator transition. The mid‐IR‐anisotropic optical response of the insulating (8 × 2) phase is interpreted in terms of electronic single particle excitations between surface electronic bands related to the In‐nanowire surface. Comparison of the measured optical transitions with DFT ab initio calculations for the hexagon model and the trimer model of the (8 × 2) structure shows evidence for the existence of the hexagon structure.
Fixed‐order robust H∞ control and control‐oriented uncertainty set shaping for systems with ellipsoidal parametric uncertainty
Authors: Sadeghzadeh Arash , Momeni Hamidreza
Published: June 2010

In this paper, sufficient conditions for robust output feedback controller design for systems with ellipsoidal parametric uncertainty are given in terms of solutions to a set of linear matrix inequalities. A polynomial method is employed to design a fixed‐order controller that assigns closed‐loop poles within a given region of the complex plane and that satisfies an H∞ performance specification. The main feature of the proposed method is that it can be extended easily for control‐oriented uncertainty set shaping using a standard input design approach. Consequently, the results can be extended to joint robust control/input design procedure whose controller structure and performance specifications are translated into the requirements on the input signal spectrum used in system identification. This way, model uncertainty set can be tuned for the robust control design procedure. The simulation results show the effectiveness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.
Ecohydraulics needs to embrace ecology and sound science, and to avoid mathematical artefacts
Authors: Lancaster Jill , Downes Barbara J.
Published: June 2010

We respond to comments on our review of the role of ecology in much of the ecohydraulics literature. Unfortunately, the commentators have attempted largely to defend the status quo without addressing the identified ecological weaknesses, and they have fallen into some philosophical and logical traps that commonly occur when researchers carry out multiple statistical tests. We maintain that many researchers routinely make incorrect assumptions about abundance–environment relationships, with the consequence that many inferences, predictions, models and management tools based on these relationships are logically flawed. The commentators' attempts to dismiss suggestions of potentially fruitful areas of research in ecohydraulics are specious and out of step with the current literature. Copyright © 2010 John Wiley & Sons, Ltd.
Application of an environmental scanning electron microscope to micromechanical fabrication
Authors: Paul B. K. , Klimkiewicz M.
Published: June 2010

Current advanced methods of micromechanical fabrication require expensive tooling or are restricted to the fabrication of lateral‐shaped microstructures. To overcome these limitations, recent efforts have usedmicroscale additive freeform fabrication (AFF) methods to prototype micromechanical structures. However, these laser‐based methods are limited in resolution. To improve the resolution of microscale AFF methods, an environmental scanning electron microscope (ESEM) was used to prototype several electron‐beam (EB)‐based microscale AFF processes. The results showed that the ESEM is capable of demonstrating process feasibility for EB‐based microscale AFF.
Antithrombotic treatment in protection against thrombogenic effects of 5‐fluorouracil on vascular endothelium: A scanning microscopy evaluation
Authors: Kinhult Sara , Albertsson Maria , Eskilsson Jan , Cwikiel Magdalena
Published: June 2010

Cardiotoxicity is a serious side effect of treatment of malignant diseases with 5‐fluorouracil (5‐FU). The underlying pathophysiologic mechanism remains unclear but clinical data suggest that the endothelium of coronary arteries may be involved. Experimental studies indicate that the endothelium is especially susceptible to 5‐FU and support the hypothesis that a thrombogenic effect of 5‐FU, secondary to its direct toxic effect on the endothelium, is one of the pathophysiologic mechanisms behind 5‐FU‐induced cardiotoxicity. In the present study we evaluate the role of antithrombotic treatment with dalteparin as protection against the thrombogenic effect of 5‐FU on the vascular endothelium in a rabbit model. The effects on the vascular endothelium of 5‐FU, dalteparin, and the combination of these two substances were evaluated with scanning electron microscopy 1, 3, 7, 14, and 30 days after treatment and compared with a control group. Very severe damage to the endothelium was seen in 5‐FU‐treated animals, often leading to intima disruption and denudation of underlying structures, with accompanying platelet accumulation and fibrin formation. The most extensive damage was observed on Day 3 after treatment. The cytotoxic effect of 5‐FU was partly reversible. The combination of 5‐FU and dalteparin gave lower scores on Day 3 because of less evidence of thrombotic events. However, the reversibility of the endothelial damage was poorer in this group, as well as in the group that received dalteparin alone. The findings support the hypothesis that antithrombotic treatment with dalteparin can protect against the thrombogenic effect of 5‐FU, secondary to its direct toxic effect on the vascular endothelium. However, the study indicates that dalteparin per se has a toxic effect on the endothelium that is different from that of 5‐FU.
Routine Ultrasound and Limited Computed Tomography for the Diagnosis of Acute Appendicitis
Authors: Toorenvliet Boudewijn R. , Wiersma Fraukje , Bakker Rutger F. R. , Merkus Jos W. S. , Breslau Paul J. , Hamming Jaap F.
Published: June 2010

Background

Acute appendicitis continues to be a challenging diagnosis. Preoperative radiological imaging using ultrasound (US) or computed tomography (CT) has gained popularity as it may offer a more accurate diagnosis than classic clinical evaluation. The optimal implementation of these diagnostic modalities has yet to be established. The aim of the present study was to investigate a diagnostic pathway that uses routine US, limited CT, and clinical re‐evaluation for patients with acute appendicitis.

Methods

A prospective analysis was performed of all patients presenting with acute abdominal pain at the emergency department from June 2005 until July 2006 using a structured diagnosis and management flowchart. Daily practice was mimicked, while ensuring a valid assessment of clinical and radiological diagnostic accuracies and the effect they had on patient management.

Results

A total of 802 patients were included in this analysis. Additional radiological imaging was performed in 96.3% of patients with suspected appendicitis (n = 164). Use of CT was kept to a minimum (17.9%), with a US:CT ratio of approximately 6:1. Positive and negative predictive values for the clinical diagnosis of appendicitis were 63 and 98%, respectively; for US 94 and 97%, respectively; and for CT 100 and 100%, respectively. The negative appendicitis rate was 3.3%, the perforation rate was 23.5%, and the missed perforated appendicitis rate was 3.4%. No (diagnostic) laparoscopies were performed.

Conclusions

A diagnostic pathway using routine US, limited CT, and clinical re‐evaluation for patients with acute abdominal pain can provide excellent results for the diagnosis and treatment of appendicitis.
Diagnosis and high incidence of hyperornithinemia‐hyperammonemia‐homocitrullinemia (HHH) syndrome in northern Saskatchewan
Authors: Sokoro AbdulRazaq A. H. , Lepage Joyce , Antonishyn Nick , McDonald Ryan , Rockman‐Greenberg Cheryl , Irvine James , Lehotay Denis C.
Published: June 2010

Mutations in the SLC25A15 gene, encoding the human inner mitochondrial membrane ornithine transporter, are thought to be responsible for hyperornithinemia‐hyperammonemia‐homocitrullinemia (HHH) syndrome, a rare autosomal recessive condition. HHH syndrome has been detected in several small, isolated communities in northern Saskatchewan (SK). To determine the incidence of HHH syndrome in these communities, a PCR method was set up to detect F188Δ, the common French‐Canadian mutation. Neonatal blood spots collected from all newborns from the high risk area were genotyped for the F188Δ mutation for seven consecutive years. Using DNA analysis, we estimated that the heterozygote frequency for the mutant allele for HHH syndrome to be about 1 in 19 individuals, predicting one affected child with HHH syndrome for approximately every 1,500 individuals (1 in 1,550 live births; 1 child every 12 years) in this isolated population. The frequency for the mutant allele for HHH syndrome in this isolated community is probably the highest in the world for this rare disorder. We determined that ornithine levels, by tandem mass spectrometry, were not abnormal in newborns with F188Δ mutation, carriers and normals. Ornithine rises to abnormally high levels at some time after birth well past the time that the newborn screening blood spot is collected. The timing or the reasons for the delayed rise of ornithine in affected children with HHH syndrome have not been determined. Newborn screening for HHH Syndrome in this high risk population is only possible by detection of the mutant allele using DNA analysis.
Whole body composition analysis by the BodPod air‐displacement plethysmography method in children with phenylketonuria shows a higher body fat percentage
Authors: Albersen Monique , Bonthuis Marjolein , de Roos Nicole M. , den van Hurk Dorine A. M. , Carbasius Weber Ems , Hendriks Margriet M. W. B. , de Sain‐van der Velden Monique G. M. , de Koning Tom J. , Visser Gepke
Published: June 2010

Background

Phenylketonuria (PKU) causes irreversible central nervous system damage unless a phenylalanine (PHE) restricted diet with amino acid supplementation is maintained. To prevent growth retardation, a protein/amino acid intake beyond the recommended dietary protein allowance is mandatory. However, data regarding disease and/or diet related changes in body composition are inconclusive and retarded growth and/or adiposity is still reported. The BodPod whole body air‐displacement plethysmography method is a fast, safe and accurate technique to measure body composition.

Aim

To gain more insight into the body composition of children with PKU.

Methods

Patients diagnosed with PKU born between 1991 and 2001 were included. Patients were identified by neonatal screening and treated in our centre. Body composition was measured using the BodPod system (Life Measurement Incorporation©). Blood PHE values determined every 1–3 months in the year preceding BodPod analysis were collected. Patients were matched for gender and age with data of healthy control subjects. Independent samples t tests, Mann–Whitney and linear regression were used for statistical analysis.

Results

The mean body fat percentage in patients with PKU (n = 20) was significantly higher compared to healthy controls (n = 20) (25.2% vs 18.4%; p = 0.002), especially in girls above 11 years of age (30.1% vs 21.5%; p = 0.027). Body fat percentage increased with rising body weight in patients with PKU only (R = 0.693, p = 0.001), but did not correlate with mean blood PHE level (R = 0.079, p = 0.740).

Conclusion

Our data show a higher body fat percentage in patients with PKU, especially in girls above 11 years of age.
Effects of microclimate, litter type, and mesh size on leaf litter decomposition along an elevation gradient in the Wuyi Mountains, China
Authors: Wang Shaojun , Ruan Honghua , Han Yong
Published: June 2010

Litter decomposition is an important ecosystem process regulated by both biotic factors (e.g., decomposers and litter types) and abiotic factors (e.g., temperature and moisture). This study examined the regulatory effects of soil fauna and microclimate on decomposition of two substrates (Castanopsis carlesiiandPinus taiwanensis) along an elevation gradient in four ecosystems of zonal vegetation types in southeastern China: evergreen broadleaf forest (EVB), coniferous forest (COF), dwarf forest (DWF), and alpine meadow (ALM). Our objective was to identify the mechanisms by which microclimate, substrate, and fauna control litter decomposition, especially where variations in ecosystem structure and environment are markedly shown across an elevation gradient. The hypotheses were as follows: (1) litter decomposition within the same litter type would decrease across the elevation gradient, (2) litter decomposition would be lower in poorer nutrient quality substrate across the four sites, and (3) litter dynamics, influenced by strong interactions among ecosystem type, litter type, and decomposers, would vary by elevation gradient due to microclimate effects (i.e., temperature and moisture). The decomposition rates ofC.carlesiiwere significantly higher than those ofP.taiwanensisat EVB, COF, and DWF sites; however, they were not significantly different at the ALM site. Low elevation forests possessed a microclimate (warm and humid) that favors decomposer activities and also appeared to possess a decomposer community adapted to consuming large amounts of leaf litter, as indicated by the rapid leaf litter loss. Litter decomposition in micro‐mesh bags proceeded more slowly compared to litter in meso‐mesh and macro‐mesh litterbags across the elevation gradient, indicating that restricting some detritivore access to litter reduced litter mass loss. We suggest that microclimate and faunal contributions to plant litter decomposition differ markedly across the ecosystems in the Wuyi Mountains.