bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the chemical structure of dithiocarbamates with different R groups on the reversible addition‐fragmentation chain transfer polymerization
Authors: Zhou Di , Zhu Xiulin , Zhu Jian , Hu Lihua , Cheng Zhenping
Published: October 2006

Four dithiocarbamates, carbazole‐9‐carbodithioic acid benzyl ester (R1), carbazole‐9‐carbodithioic acid naphthalen‐1‐ylmethyl ester (R2), 2‐(carbazole‐9‐carbothioylsulfanyl)‐2‐methyl‐propionic acid ethyl ester (R3), and (carbazole‐9‐carbothioylsulfanyl)‐phenyl‐acetic acid methyl ester (R4), were synthesized and used to the reversible addition‐fragmentation chain transfer (RAFT) polymerizations of styrene (St), methyl methacrylate (MMA), and methyl acrylate (MA), respectively. The influence of chemical structure of dithiocarbamates with different R groups on the RAFT polymerizations was investigated. The results showed that the four RAFT agents were effective RAFT agents for the polymerizations of styrene or MA, and that the polymerizations were well‐controlled with the characteristics of controlled/“living” polymerization. The polymerization rate of styrene with thermal initiation was markedly influenced by the chemical structures of the group R in dithiocarbamates, and decreased in the order of R3 > R2 > R4 > R1. For the polymerization of MA, the efficiency of RAFT agents was in the following order: R2–R3 > R1 > R4. However, they were not efficient enough to control the polymerization of MMA. The obtained polystyrene (PSt) with carbazole group labeled strongly absorbed UV light at 294 nm and emitted fluorescent light in N,N‐dimethyl formamide (DMF). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 982–988, 2007
The mechanical and tribological properties of PTFE filled with PTFE waste powders
Authors: Xiang Dinghan , Tao Kemei
Published: October 2006

Polytetrafluoroethylene (PTFE) composites filled with PTFE waste offer interesting combination of tribological properties and low cost. PTFE composites waste was mechanically cut and sieved into powders. PTFE composites filled with PTFE waste powders were prepared by compression molding. Friction and wear experiments were carried out in a reciprocating sliding tribotester at a reciprocating frequency of 1.0 Hz, a contact pressure of 5.5 MPa, and a relative humidity of (60 ± 5)%. PTFE materials slid against a 45 carbon steel track. Results showed that a PTFE composite (B) filled with 20 wt % PTFE waste exhibited a coefficient of steady‐state friction slightly higher than that of unfilled PTFE (A), while wear resistance over two orders of magnitude higher than that of unfilled PTFE (A). Another PTFE composite filled with PTFE waste and alumina nanoparticles exhibited the highest wear resistance among the three PTFE materials. This behavior originates from the effective reinforcement of PTFE waste as a filler. It was experimentally confirmed that the low cost recycling of PTFE waste without by‐products is feasible. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1035–1041, 2007
Using analog assessment procedures for determining the effects of a gluten‐free and casein‐free diet on rate of problem behaviors for an adolescent with autism
Authors: Irvin Douglas S.
Published: October 2006

The behavioral effects of a gluten/casein‐free diet were evaluated for an adolescent with autism who displayed several forms of aberrant behavior. An analog assessment was used to measure behavioral response rates within four conditions with type of diet controlled using a BABA design. Results suggested that a gluten/casein‐free diet did not serve as an abolishing operation for assessed problem behaviors. Both the limitations and generality of this finding are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Error correction in discrimination training for children with autism
Authors: Smith Tristram , Mruzek Daniel W. , Wheat Leigh Ann , Hughes Carrie
Published: October 2006

Three procedures for correcting errors made during discrimination training were examined: error statement (saying ‘no’), modeling the correct response, and No Feedback. Six children with autism (age 3–7 years) were taught to match words to pictures with each of the three procedures, and the number of trials to mastery was compared across conditions. Results varied across participants. Two participants performed as well with no feedback as they did with an error correction procedure; two acquired skills slightly more quickly with an error correction procedure than with no feedback, but showed no difference between error correction procedures; one did best with error statement; and one did best with modeling. Results indicate that the choice of error correction procedure can have a large effect on rate of skill acquisition but that the optimal procedure may vary across individuals. Copyright © 2006 John Wiley & Sons, Ltd.
Cover Picture: Structural and Magnetic Resolution of a Two‐Step Full Spin‐Crossover Transition in a Dinuclear Iron(II) Pyridyl‐Bridged Compound (Chem. Eur. J. 32/2006)
Authors: Amoore Jarrod J. M. , Kepert Cameron J. , Cashion John D. , Moubaraki Boujemaa , Neville Suzanne M. , Murray Keith S.
Published: October 2006

New structural data on the nature of the spin transition in dinuclear iron(II) spin‐crossover materials has been obtained from studying [Fe2(ddpp)2(NCS)4]⋅4 CH2Cl2. In their Full Paper on page 8220 ff., C. J. Kepert, K. S. Murray et al. describe the synthesis and characterisation of this compound, particularly in regard to two‐step transitions, for which it provides the first structure of high‐spin–low‐spin molecules at the plateau region.
Plasmatechnologie – Neue Wege zur Entkeimung von Packstoffmaterialien
Authors: Langowski H. C. , Muranyi P. , Wunderlich Joachim
Published: October 2006

Der Einsatz von Gasplasmen ist eine innovative Technologie für die nichtthermische Entkeimung bzw. Sterilisation von Packstoffen. Unter Ausnutzung spezifischer Wirkmechanismen wie UV‐Strahlung, Radikalchemie und Ionenbeschuss können Oberflächen effizient entkeimt und von Biomolekülen wie z. B. Pyrogenen befreit werden. Aufgrund der moderaten Temperaturen sind Gasplasmen besonders für die Behandlung von thermolabilen Materialien wie Kunststoffen geeignet. Die hohe Leistungsfähigkeit bei Behandlungszeiten im Sekundenbereich und die Vielseitigkeit der Plasmatechnik ermöglichen diverse Applikationen in der Verpackungstechnik.
Thermische und hydrostatische Inaktivierung von Bakteriophagen
Authors: Müller‐Merbach M. , Hinrichs J.
Published: October 2006

Von 55 Laktokokkenphagen einer aktuellen Probenerhebung überstanden 40 % der Isolate eine 5‐minütige Behandlung bei 80 °C. Die kombinierte hydrostatisch‐thermische Inaktivierung wird an einem Modellphagen (P008) untersucht. Mittlere Drücke und Temperaturen wirken antagonistisch, wie durch Kurven gleichen Effekts in einem Druck‐Temperatur‐Diagramm demonstriert wird.
Sterilfiltration von Flüssigkeiten und Gasen
Authors: Brendel‐Thimmel U. , Jaenchen R. , Schlamp F.
Published: October 2006

Die Sterilfiltration von Flüssigkeiten und Gasen mittels Membranfiltration ist ein sicheres Verfahren zur Abtrennung von Mikroorganismen und ein wesentlicher, die Produktqualität bestimmender Prozessschritt. Neben den Materialien und Bauformen bestimmen Flussleistungen, Feinheit und eine abgestimmte Vorfiltration ebenso den Erfolg und die Wirtschaftlichkeit einer Sterilfiltration wie die richtige Installation und Handhabung im Prozess. In diesem Beitrag werden Kriterien für die Auswahl der geeigneten Filtermaterialien und das Design der Anlage und des Prozesses dargelegt. Die herstellerseitige Qualifizierung und die anwenderseitige Validierung tragen zu einer korrekten Funktion der Sterilfilter ebenso bei wie die kontinuierliche Überwachung wichtiger Prozessparameter und die Durchführung von Integritätstests. Je nach Industriezweig und in Abhängigkeit der Produkte, deren Verunreinigungen und der typischen Keimspektren werden unterschiedliche Sterilfilter eingesetzt.
Hygienic Design von Anlagen und deren Qualifizierungsmethoden
Authors: Hofmann J. , Sommer K.
Published: October 2006

Die Vermeidung von Lebensmittelkontaminationen und die Erhöhung der Produktsicherheit ist das Ziel eines jeden Lebensmittelproduzenten. Mit der reinigungsfreundlichen Gestaltung von Bauteilen und Anlagen für die Lebensmittelherstellung befasst sich das Hygienic Design. Es definiert grundlegende Anforderungen an die Auswahl von Werkstoffen und deren Oberflächenqualitäten. Wichtige Gestaltungskriterien müssen eingehalten werden, damit eine vollständige, sichere und reproduzierbare Reinigung der Anlagen ermöglicht wird. Nur so kann die Gefahr einer Produktkontamination vermieden werden. Damit stellt dieses Themengebiet ein wichtiges Glied in der Kette aller Einflussfaktoren hinsichtlich der Produktqualität dar. Dieser Beitrag soll dazu beitragen, die Grundzüge der reinigungsgerechten Konstruktion von Komponenten und Anlagen besser verstehen zu können und über verschiedene Qualifizierungsmethoden aufklären.
Ultrahochdruckverfahren zur Keiminaktivierung
Authors: Rademacher B.
Published: October 2006

Die Ultrahochdruckbehandlung von Lebensmitteln mit dem Ziel der Inaktivierung von Mikroorganismen ist eine Alternative zu den etablierten thermischen Verfahren. Schon seit einigen Jahren sind hochdruckbehandelte Produkte auch in Europa kommerziell verfügbar. Der Beitrag stellt Möglichkeiten, wichtige Aspekte der Anwendung und Grenzen der Hochdrucktechnologie vor.
Maschinen und Anlagenhygiene – Gesetzliche Rahmenbedingungen und Anforderungen aus Regelwerken für Lebensmittel‐ und pharmazeutische Produktion
Authors: Bellin H.‐W.
Published: October 2006

Alle Richtlinien der EG müssen in den Mitgliedsländern in entsprechende nationale Regelungen umgesetzt werden. Die jeweiligen Behörden der Mitgliedsstaaten erhalten dann Vollzugsgrundlagen und können damit über die Einhaltung der Vorgaben wachen und dürfen entsprechende Zwangsmaßnahmen einleiten. In Deutschland liegt die Überwachung der Gesetze bei den Länderbehörden, z. B. der Gewerbeaufsicht. Richtlinien sind Mindestanforderungen und dürfen, wenn bereits vor in Kraft treten der Richtlinie ein höheres Niveau herrschte, durch die nationale Gesetzgebung verschärft werden. Im Gegensatz zu den Richtlinien wirken Europäische Verordnungen unmittelbar, und es bedarf keiner nationalen Umsetzung. Ebenso wie die Richtlinien gehen aber auch die Verordnungen dem nationalen Recht in ihrer Anwendung vor.
Steriltechnik in der Herstellung pharmazeutischer Produkte
Authors: Winter G.
Published: October 2006

Die den Pharmabereich kennzeichnenden Besonderheiten in der Steriltechnik sollen in diesem Beitrag herausgearbeitet werden. Dabei wird auf Neuerungen und aktuelle Trends sowie auf die für den Pharmabereich typischen behördlichen Regulierungen eingegangen. Der verstärkte Einsatz von Isolatortechnik und der neuen „RABS”︁‐Konzepte zur vollständigen Trennung von Produkt und Personal werden kommentiert ebenso wie Weiterentwicklungen von automatischen Abfüllprozessen. Im Bereich der Reinigung Produkt berührender Oberflächen zeichnen sich neue Trends ab. Außerdem stehen die Reinigungsvalidierung an „Multi‐Purpose”︁‐Anlagen und der fortschreitende Einsatz von Einmalsystemen im Mittelpunkt. Einen weiteren Schwerpunkt bilden neue Packmittelkonzepte, insbesondere sog. „RTF”︁ = „ready to fill”︁‐Einheiten und moderne Devices. Abschließend wird kurz die Initiative der FDA zum Thema „Process Analytical Technologies”︁ (PAT) kommentiert.
Phenotypic diversity is the cornerstone of evolution: Variation in cortical field size within short‐tailed opossums
Authors: Karlen Sarah J. , Krubitzer Leah
Published: October 2006

Natural selection operates on phenotypic variation that exists within a population. Variable aspects of cortical organization, such as the size and connections of a cortical field, can generate differences in behavior, which is a target of natural selection. Yet studies pertaining to within‐species variability in cortical organization are limited. In the present investigation, we examined variation in brain size, cortical sheet size, and primary sensory cortical field sizes in the adult short‐tailed opossum (Monodelphis domestica). Within individuals, we found no significant difference between the right and left hemispheres in the overall size of the dorsolateral cortex or in primary cortical field sizes. Between individuals, we found relatively little intraspecies variation in brain weight, brain volume, and cortical sheet area for the dorsolateral neocortex and pyriform cortex; however, we observed a large degree of variability in body weight and primary sensory cortical field size, as defined by myeloarchitecture. Further, we found that the size of each cortical field correlated with the size of the other cortical fields as well as with the total size of the dorsolateral cortex. Here we discuss the possible sources of variation and examine the relationship between cortical field size and sensory processing abilities and behaviors across species. Since behavior is the target of natural selection, variation in cortical field size across individuals may supply the raw material necessary for cortical field evolution. J. Comp. Neurol. 499:990–999, 2006. © 2006 Wiley‐Liss, Inc.
Ectopic expression of the homeobox gene Cux‐1 rescues calcineurin inhibition in mouse embryonic kidney cultures
Authors: Alcalay Neal I. , Brantley Jennifer G. , Sharma Madhulika , Gooch Jennifer L. , Vanden Heuvel Gregory B.
Published: October 2006

Cux‐1 is a murine homeobox gene structurally related to Drosophila cut. Cux‐1 is highly expressed in the nephrogenic zone of the developing kidney, where its expression coincides with cell proliferation. Cux‐1 functions as a transcriptional repressor of the cyclin kinase inhibitors (CKI) p21 and p27. Cux‐1 DNA binding activity is negatively regulated by phosphorylation, and dephosphorylation of Cux‐1 results in increased DNA binding. Transgenic mice ectopically expressing Cux‐1 develop renal hyperplasia associated with the down‐regulation of the CKI p27. Calcineurin A (CnA) α (−/−) mice display renal hypoplasia associated with the ectopic expression of p27. CnA is a serine/threonine phosphatase activated by intracellular calcium. Inhibiting CnA with cyclosporin A (CsA) leads to nephron deficit in rat metanephric organ cultures and apoptosis in various renal cell lines. To determine whether the ectopic expression of p27 in CnA‐α −/− kidneys results from the down‐regulation of Cux‐1, metanephroi from embryonic Cux‐1 transgenic and wild‐type mice were harvested and cultured with CsA for 5 days. CsA treatment significantly inhibited growth of wild‐type metanephroi. In contrast, CsA‐treated Cux‐1 transgenic kidney cultures were not growth inhibited, but showed high levels of cell proliferation in the nephrogenic zone. Moreover, in CsA‐treated Cux‐1 transgenic kidney cultures, p27 was not expressed in the nephrogenic zone, but only up‐regulated in maturing glomeruli and tubules. Taken together, our results demonstrate that ectopic expression of Cux‐1 can rescue the effects of CsA inhibition of CnA and suggest that Cux‐1 may be regulated by calcineurin A. Developmental Dynamics 236:184–191, 2007. © 2006 Wiley‐Liss, Inc.
Computational Determination of Iron Hyperfine Interactions in Organometallics Using Small Transverse External Magnetic Fields
Authors: Nowik Israel , Herber Rolfe H.
Published: October 2006

A number of organometallic and related iron‐containing compounds have been examined by transmission 57Fe Mössbauer spectroscopy in modest (0–2.4 T) magnetic fields in order to determine the sign of the quadrupole‐splitting hyperfine parameter (QS) as well as the internal magnetic field in derived paramagnetic solids. A computer program has been developed to extract these parameters from the spectroscopic data. The sign of the QS is found to be positive in the neutral ferrocenoid solids and negative in the derived cationic complexes. The internal hyperfine field makes a positive contribution in the cationic ferrocenoids and a negative contribution in FeF2 and Fe(phen)2(SCN)2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Borax as an Efficient Metal‐Free Catalyst for Hetero‐Michael Reactions in an Aqueous Medium
Authors: Hussain Sahid , Bharadwaj Saitanya K. , Chaudhuri Mihir K. , Kalita Harjyoti
Published: October 2006

Borax, a naturally occurring material, very efficiently catalyzed the conjugate addition of thiols, dithiols and amines to α,β‐unsaturated ketones, nitriles, amides, aldehydes and esters in an aqueous medium to afford the corresponding Michael adducts in good yields at room temperature. Recycling of the catalyst and scaling up of the reactions are important attributes of this catalysis. The reactions of thiols and dithiols were relatively more facile than those of the corresponding amines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Material surfaces affect the protein expression patterns of human macrophages: A proteomics approach
Authors: Dinnes Donna Lee M. , Marçal Helder , Mahler Stephen M. , Santerre J. Paul , Labow Rosalind S.
Published: October 2006

Monocyte‐derived macrophages (MDM) are key inflammatory cells and are central to the foreign body response to implant materials. MDM have been shown to exhibit changes in actin cytoskeleton, multinucleation, cell size, and function in response to small alterations in polycarbonate‐urethane (PCNU) surface chemistry. Although PCNU chemistry has an influence on de novo protein synthesis, no assessments of the protein expression profiles of MDM have yet been reported. The rapid emerging field of expression proteomics facilitates the study of changes in cellular protein profiles in response to their microenvironment. The current study applied proteomic techniques, 2‐dimensional electrophoresis (2‐DE) combined with MALDI‐ToF (matrix assisted laser desorption ionization–time of flight) mass spectrometry, to determine differences in MDM protein expression influenced by PCNU. Results indicated that MDM responded to material chemistry by modulation of structural proteins (i.e. actin, vimentin, and tubulin). Additionally, intracellular protein modulation which requires proteins responsible for trafficking (i.e. chaperone proteins) and protein structure modification (i.e. bond rearrangement and protein folding) were also altered. This study demonstrated for the first time that a proteomics approach was able to detect protein expression profile changes in MDM cultured on different material surfaces, forming the basis for utilizing further quantitative proteomics techniques that could assist in elucidation of the mechanisms involved in MDM–material interaction. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Development of leiomyosarcoma of the uterus in MMTV‐CR‐1 transgenic mice
Authors: Strizzi L , Bianco C , Hirota M , Watanabe K , Mancino M , Hamada S , Raafat A , Lawson S , Ebert AD , D'Antonio A , Losito S , Normanno N , Salomon DS
Published: October 2006

Overexpression of Cripto‐1 (CR‐1) in FVB/N mice using the MMTV‐LTR promoter results in increased mammary tumourigenesis in these female transgenic mice (MMTV‐CR‐1). Here, we characterize uterine tumours that developed in 15/76 (19.7%) of MMTV‐CR‐1 female nulliparous or multiparous mice during 24 months of observation compared with 0/33 (0%) of FVB/N normal control mice observed during the same time period (p < 0.01). The uterine tumours collected from the MMTV‐CR‐1 mice were classified as leiomyosarcomas and found to express the CR‐1 transgene by polymerase chain reaction analysis and immunohistochemistry. Detection by western blot analysis showed higher levels of phosphorylated (P) forms of c‐src, Akt, GSK‐3β, and dephosphorylated (DP)‐β‐catenin in lysates from MMTV‐CR‐1 uterine leiomyosarcomas in comparison with lysates from normal control FVB/N uteri. Immunostaining showed increased nuclear localization of β‐catenin in the MMTV‐CR‐1 uterine leiomyosarcomas. Increased immunostaining for CR‐1 was detected in 9/13 (69.2%) cases of human leiomyosarcoma compared with staining in 3/15 (20%) human leiomyoma sections. Stronger immunostaining for P‐src, P‐Akt, P‐GSK‐3β and increased nuclear localization of β‐catenin was also seen in human leiomyosarcomas in comparison with leiomyomas. Normal human uterine smooth muscle (UtSM) cells treated with exogenous soluble rhCR‐1 showed increased levels of P‐src, P‐Akt, P‐GSK‐3β and dephosphorylated (DP)‐β‐catenin and increased proliferation (p < 0.05) and migration (p < 0.01) in comparison with untreated control UtSM cells. Inhibitors against c‐src, Akt or β‐catenin, individually or in combination, significantly reduced CR‐1‐induced migration. These results suggest a role for CR‐1 during uterine tumourigenesis either directly by activating c‐src and Akt and/or via cross‐talk with the canonical Wnt signalling pathway, as suggested by the increased expression of P‐GSK‐3β, DP‐β‐catenin, and increased nuclear localization of β‐catenin in human and MMTV‐CR‐1 mice leiomyosarcomas. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Pocket and antipocket conformations for the CH4@C84 endohedral fullerene
Authors: Rehaman Abdul , Gagliardi Laura , Pyykkö Pekka
Published: October 2006

The endohedral fullerene CH4@C84 has been studied using density functional theory (DFT) and second‐order Møller–Plesset perturbation theory (MP2). In addition to the structure with a CH bond of CH4 in a tetrahedral pocket conformation, we find an alternative minimum, very close in energy (6.3–9.5 kJ/mol higher according to the level of theory), with the methane inverted, which we call the antipocket conformation. Computed IR spectra are reported for CH4@C84 and also for the reference system CH4@C60. The calculated vibrational levels, in a harmonic approximation, reveal close‐lying translational, librational, and shell‐vibrational modes. The results are also presented for the isoelectronic species NH@C60. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
The Right to Reasonable Exit and a Religious Education for Moderate Autonomy
Authors: Lester Emile
Published: October 2006

Political and comprehensive liberals are both pessimistic about finding a satisfactory way to resolve the debate over whether and how to expose students in public schools to religion. An examination of John Tomasi's Liberalism beyond Justice and William Galston's Liberal Pluralism reveals that a central cause of this pessimism is the presumption that an education for autonomy must encourage students to become rational choosers of their beliefs. This essay suggests that it is possible to found an education for autonomy on the more modest goal of ensuring that students have a reasonable ability to exit from their communities when they feel that membership is too painful. An education for exit would involve exposing students at the high school level to alternative religious beliefs to ensure they are aware that it might be possible to lead tolerable lives and achieve salvation outside of their communities of origin.
The Divine Instinct? Rousseau and Conscience
Authors: Marks Jonathan
Published: October 2006

Political theorists have long disagreed about what Rousseau's account of conscience means. While most approaches to that account focus on the “Profession of Faith of the Savoyard Vicar,” this essay focuses on another aspect of Emile, the development of conscience in Emile himself. First, I argue that conscience is transformed from problem to solution when self-love is transformed, first into gratitude, then, with the aid of religion, rhetoric, and imagination, into duty. Those who insist that conscience is rooted in passion are right, though that passion is not necessarily low. Second, those who argue that Rousseau's teaching on conscience, as set forth in the First Discourse and elsewhere, is a salutary untruth are right. Emile's conscience shouts “virtue!” not because conscience always does so in uncorrupted souls once they enter the moral world but because it has had voice lessons from Emile's governor, who makes liberal use of illusion and rhetoric.
Synoptic maps of temperature and velocity within the Subantarctic Front south of Australia
Authors: Tracey K. L. , Watts D. R. , Meinen C. S. , Luther D. S.
Published: October 2006

From April 1995 to March 1997 a 450‐km array of inverted echo sounders, horizontal electric field recorders, and current meters measured the horizontal and vertical structure of the current, temperature, and salinity fields associated with the Subantarctic Front (SAF) south of Australia. Synoptic maps of the temperature and velocity fields often show the SAF divided into two zonally separated jets, which are also found in the mean. These jets were in close proximity yet directed toward different azimuths. The daily maps also show that the SAF often flowed as a single strong jet, during which times it underwent vigorous meandering, with crest‐to‐trough meridional distances ∼250 km. These meanders stalled within the array and contorted to form “S”‐shaped paths. In one case a cold‐core ring was formed. Propagating meanders have periods of 20–70 days, wavelengths of 240–420 km, and phase speeds of 12–6 km d−1. Deep currents reveal strong cyclones and anticyclones propagating primarily eastward through the array beneath the meandering jet. Thus, at times the deep flow is aligned with the upper flow, whereas at other times, significant barotropic flows cross the upper front. Occasionally, the northern Polar Front was also found within the array. The observed variability illustrates how the interaction of a meandering current with transient features such as meanders and eddies makes the identification of a front difficult when a single isotherm or isopycnal is utilized as the definition.
Investigation of seasonal prediction of the South American regional climate using the nested model system
Authors: De Sales Fernando , Xue Y.
Published: October 2006

The National Centers for Environmental Prediction (NCEP) regional Eta model was nested in the NCEP Atmosphere General Circulation Model (AGCM) to provide an assessment of the dynamic downscaling method in seasonal climate simulations over South America (SA). This study examined 15 seasons, summer and winter, of significant El Niño–Southern Oscillation years. Results showed that the nested model improved the simulation of seasonal mean lower and upper level circulations in both warm and cold seasons. The summer mean meridional wind along 20°S in the nested model simulation exhibited two jet cores, one located just east of the Andes associated with the South American low level jet (SALLJ) and a second, shallower jet located over eastern Brazil. Conversely, winter cross sections showed only the SALLJ, with higher wind speeds. These features are consistent with observation. AGCM results did not show any noticeable jet structure in either season. The nested model also produced better simulations of seasonal mean rainfall and 2‐m temperature. Summer (winter) precipitation root‐mean‐square error averaged over the entire continent was reduced from 2.09 (2.97) mm d−1 in the AGCM to 1.37 (2.33) mm d−1 in the nested model. The improvement persisted during the entire simulation period over selected areas of the continent. Overall, the Eta model reduced the rainfall positive bias over northern SA and negative bias over the subtropics in the AGCM simulation because of better representation of moisture transport by the SALLJ. However, the simulation of the Intertropical Convergence Zone by the nested model was weak because of weak moisture flux convergence. Its possible causes are discussed in the paper.
Methylation of aquaporins in plant plasma membrane
Authors: Santoni Véronique , Verdoucq Lionel , Sommerer Nicolas , Vinh Joëlle , Pflieger Delphine , Maurel Christophe
Published: October 2006

A thorough analysis, using MS, of aquaporins expressed in plant root PM (plasma membrane) was performed, with the objective of revealing novel post-translational regulations. Here we show that the N-terminal tail of PIP (PM intrinsic protein) aquaporins can exhibit multiple modifications and is differentially processed between members of the PIP1 and PIP2 subclasses. Thus the initiating methionine was acetylated or cleaved in native PIP1 and PIP2 isoforms respectively. In addition, several residues were detected to be methylated in PIP2 aquaporins. Lys3 and Glu6 of PIP2;1, one of the most abundant aquaporins in the PM, occurred as di- and mono-methylated residues respectively. Ectopic expression in Arabidopsis suspension cells of PIP2;1, either wild-type or with altered methylation sites, revealed an interplay between methylation at the two sites. Measurements of water transport in PM vesicles purified from these cells suggested that PIP2;1 methylation does not interfere with the aquaporin intrinsic water permeability. In conclusion, the present study identifies methylation as a novel post-translational modification of aquaporins, and even plant membrane proteins, and may represent a critical advance towards the identification of new regulatory mechanisms of membrane transport.
Heparan sulfate 6-O-endosulfatases: discrete in vivo activities and functional co-operativity
Authors: Lamanna William C. , Baldwin Rebecca J. , Padva Michael , Kalus Ina , ten Dam Gerdy , van Kuppevelt Toin H. , Gallagher John T. , von Figura Kurt , Dierks Thomas , Merry Catherine L. R.
Published: October 2006

HS (heparan sulfate) is essential for normal embryonic development. This requirement is due to the obligatory role for HS in the signalling pathways of many growth factors and morphogens that bind to sulfated domains in the HS polymer chain. The sulfation patterning of HS is determined by a complex interplay of Golgi-located N- and O-sulfotransferases which sulfate the heparan precursor and cell surface endosulfatases that selectively remove 6-O-sulfates from mature HS chains. In the present study we generated single or double knock-out mice for the two murine endosulfatases mSulf1 and mSulf2. Detailed structural analysis of HS from mSulf1−/− fibroblasts showed a striking increase in 6-O-sulfation, which was not seen in mSulf2−/− HS. Intriguingly, the level of 6-O-sulfation in the double mSulf1−/−/2−/− HS was significantly higher than that observed in the mSulf1−/− counterpart. These data imply that mSulf1 and mSulf2 are functionally co-operative. Unlike their avian orthologues, mammalian Sulf activities are not restricted to the highly sulfated S-domains of HS. Mitogenesis assays with FGF2 (fibroblast growth factor 2) revealed that Sulf activity decreases the activating potential of newly-synthesized HS, suggesting an important role for these enzymes in cell growth regulation in embryonic and adult tissues.
Vapor-liquid-solid growth of silicon nanowires by chemical vapor deposition on implanted templates
Authors: Christiansen S. , Schneider R. , Scholz R. , Gösele U. , Stelzner Th. , Andrä G. , Wendler E. , Wesch W.
Published: October 2006

We show the realization of a distinctive nanoscale metal template for the vapor-liquid-solid growth of semiconductor nanowires. The template is based on the high-dose implantation of metal ions into silicon substrates and subsequent annealing upon which the atoms agglomerate. In case the wafer is amorphized at the surface upon implantation and the metal atoms reside within the amorphized part of the wafer, a high diffusion coefficient (holds for Au) of the metal atoms in amorphous silicon (compared to crystalline silicon) yields agglomeration of metal atoms at the wafer surface and the formation of supercritical metal nanoparticles. We show the implantation of gold (dose at least 1×1016cm−2) and discuss the option to use this type of template formation with other metals, such as gallium, indium, aluminum, and palladium, which are partly easy to be oxidized.
Canonical and microcanonical Monte Carlo simulations of lattice-gas mixtures
Authors: Fiore Carlos E. , Henriques Vera B. , de Oliveira Mario J.
Published: October 2006

We propose strict canonical and microcanonical Monte Carlo algorithms for an arbitrary lattice-gas binary mixture. We deduce formulas that allow us to obtain field quantities over the ensembles in which their conjugate extensive quantities are conserved. As an example, we have considered a lattice-gas mixture that is equivalent to the spin-1 Blume-Emery-Griffiths model [Phys. Rev. A 4, 1071 (1971)]. For a finite system and near a phase coexistence, the field as a function of its extensive conjugate shows a loop that disappears in the thermodynamic limit giving rise to the usual tie line. The first-order phase transition was determined by the use of three criteria.
Electrochemical stabilization of porous silicon multilayers for sensing various chemical compounds
Authors: Salem M. S. , Sailor M. J. , Harraz F. A. , Sakka T. , Ogata Y. H.
Published: October 2006

Porous silicon rugate filters are fabricated and investigated for their ability to sense chemical species. The durability of the filter is tested by allowing the structure to undergo many cycles of adsorption and desorption of vapor-phase ethanol molecules. The characteristic reflectivity peak of the structure exhibits a relative blueshift of 2.7% after 86 adsorption∕desorption cycles. The observed shift is ascribed to the formation of silicon dioxide, which has a lower refractive index than that of silicon. In order to stabilize the structure against oxidation expected from cycling and environmental exposure, the filter is subjected to electrochemical oxidation in an aqueous sulfuric acid electrolyte. The treatment dramatically improves stability of the sensor; a relative blueshift of <0.4% is observed after 100 adsorption∕desorption cycles for this sensor. The sensitivity of the sensor is also affected by electrochemical oxidation: the response to saturated ethanol in air changes from Δλ=100nm to Δλ=70nm, respectively. Theoretical calculations using the Bruggeman effective medium approximation and the characteristic matrix method indicate that up to 15% (by volume) of silicon is transformed to silicon dioxide by the electrochemical oxidation procedure. This volume ratio is close to that estimated from Auger electron spectroscopy measurements.
Enhanced optical waveguide light mode spectroscopy via detection of fluorophore absorbance
Authors: Halter Martin , Gabi Michael , Textor Marcus , Vörös Janos , Grandin H. Michelle
Published: October 2006

A novel technique based on surface sensitive absorbance detection using an optical waveguide light mode spectroscopy (OWLS) instrument is presented. The proof of concept for this extension of a standard technique is demonstrated by painting an increasing number of ink lines on a waveguide, perpendicular to the light path, while monitoring the outcoupled light intensity. Furthermore, by the adsorption of poly(L-lysine)-graft-poly(ethylene glycol) as a model system with contents of 5%, 10%, 25%, and 50% labeled polymer, the in situ performance is demonstrated, and the absorbance signal is calibrated such that it can be converted into adsorbed mass. The simultaneous detection of labeled and label-free species allows for the study of complex experimental setups whereby monitoring of adsorption, desorption, and even exchange processes becomes possible. The sensitivity of the absorbance detection exceeds standard OWLS by one to two orders of magnitude.
Three-channel x-ray crystal spectrometer for diagnosing high energy density plasmas
Authors: Baronova E. , Bucher B. , Haas D. , Fedin D. , Stepanenko A. , Beg F. N.
Published: October 2006

A novel spectrometer is designed, with three convex crystals. This spectrometer records simultaneous time integrated and time resolved spectra and can work as a polarimeter. The resolution, dispersion, and energy range of the spectrometer have been calculated using a ray tracing technique. The spectrometer has been used on an 80kA current x-pinch pulser to record the L-shell spectra of various wire materials (Al, Ni, Cu, Mo, and W).
Evolution of surface morphology in TiNiCu shape memory thin films
Authors: Fu Y. Q. , Sanjabi S. , Barber Z. H. , Clyne T. W. , Huang W. M. , Cai M. , Luo J. K. , Flewitt A. J. , Milne W. I.
Published: October 2006

A transition of film surface morphology between wrinkling and surface relief during heating/cooling is reported for a sputtered TiNiCu thin film shape memory alloy. The mechanisms for this transition are discussed based on film stress evolution. During annealing surface wrinkling occurs to relieve compressive stress in the film, while the surface relief morphology occurs during cooling due to the martensitic transformation, which relieves tensile stress.
Coarse grained model of entangled polymer melts
Authors: Rakshit A. , Picu R. C.
Published: October 2006

A coarse graining procedure aimed at reproducing both the chain structure and dynamics in melts of linear monodisperse polymers is presented. The reference system is a bead-spring-type representation of the melt. The level of coarse graining is selected equal to the number of beads in the entanglement segment, Ne. The coarse model is still discrete and contains blobs each representing Ne consecutive beads in the fine scale model. The mapping is defined by the following conditions: the probability of given state of the coarse system is equal to that of all fine system states compatible with the respective coarse state, the dissipation per coarse grained object is similar in the two systems, constraints to the motion of a representative chain exist in the fine phase space, and the coarse phase space is adjusted such to represent them. Specifically, the chain inner blobs are constrained to move along the backbone of the coarse grained chain, while the end blobs move in the three-dimensional embedding space. The end blobs continuously redefine the diffusion path for the inner blobs. The input parameters governing the dynamics of the coarse grained system are calibrated based on the fine scale model behavior. Although the coarse model cannot reproduce the whole thermodynamics of the fine system, it ensures that the pair and end-to-end distribution functions, the rate of relaxation of segmental and end-to-end vectors, the Rouse modes, and the diffusion dynamics are properly represented.
Protein domain connectivity and essentiality
Authors: da F. Costa L. , Rodrigues F. A. , Travieso G.
Published: October 2006

Protein-protein interactions can be properly modeled as scale-free complex networks, while the lethality of proteins has been correlated with the node degrees, therefore defining a lethality-centrality rule. In this work the authors revisit this relevant problem by focusing attention not on proteins as a whole, but on their functional domains, which are ultimately responsible for their binding potential. Four networks are considered: the original protein-protein interaction network, its randomized version, and two domain networks assuming different lethality hypotheses. By using formal statistical analysis, they show that the correlation between connectivity and essentiality is higher for domains than for proteins.
Fabrication of a bunch of sub-30-nm nanofibers inside microchannels using photopolymerization via a long exposure technique
Authors: Park Sang Hu , Lim Tae Woo , Yang Dong-Yol , Cho Nam Chul , Lee Kwang-Sup
Published: October 2006

Experimental studies on the fabrication of sub-30-nm nanofibers using two-photon initiated photopolymerization (TPP) have been carried out. To generate nanofibers at the interior region of microstructures, a photopolymerization method involving a long laser-exposure technique (LET) is proposed. A multitude of nanofibers with a notably high resolution (about 22nm) in TPP were produced using the LET. Furthermore, it is also demonstrated that thin interconnecting networks were created regularly in a weakly polymerized region existing around the boundary of a densely polymerized voxel, allowing for the creation of various embossing patterns. By controlling the distance between adjacent voxels or lines, a selective generation of nanofibers in a local area is possible, which leads to the fabrication of high-functional filters and mixers. Embossing patterns and microchannels including nanofibers inside were fabricated by the LET so as to demonstrate the practical feasibility of this approach. These sub-30-nm nanofibers may find meaningful applications such as biofilters, mixers, and photon emitters in diverse research fields.
High-current oversized annular electron beam formation for high-power microwave research
Authors: Konoplev I. V. , Cross A. W. , MacInnes P. , He W. , Whyte C. G. , Phelps A. D. R. , Robertson C. W. , Ronald K. , Young A. R.
Published: October 2006

The authors report the study of a high-current accelerator, capable of producing thin (2mm) annular, mildly relativistic (450keV) electron beams (up to 1.5kA) of diameter of 70mm. Propagation of an electron beam through a 2m long, coaxial beam channel, with inner and outer conductor radii of 30 and 40mm, respectively, was demonstrated with the electron beam current at the beam-channel output measured using a Rogowski coil. The results obtained are compared with those predicted via numerical simulation. The electron beam obtained was used for proof-of-concept work demonstrating the operation of a high-power maser operating at millimeter wavelengths, using two-dimensional distributed feedback.
Origin of ferromagnetism of (Co,Al)-codoped ZnO from first-principles calculations
Authors: Zhang Tao , Song Li-Xin , Chen Zhi-Zhan , Shi Er-Wei , Chao Liu-Xue , Zhang Hua-Wei
Published: October 2006

Magnetic mechanisms for the (Co,Al)-codoped ZnO, based on the first-principles calculations, are evaluated. Additional electrons induced by Al doping can stabilize the ferromagnetic state in Co-doped ZnO. The Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction may be the dominant mechanism when the distance between Co and Al is far away, while the double-exchange interaction may gain an advantage over the RKKY when the distance is near. The multiple mechanisms can explain the relationship between the magnetic performance and the relative substitutional site of Al. The study yields insight into the origin of the ferromagnetism of ZnO-based materials.
Sensitivity enhancement of thermal infrared imagers with bimaterial cantilevers through piezoelectric actuation
Authors: Yan Dong , Lal Amit
Published: October 2006

Sensitivity enhancement of a thermal infrared imager with bimaterial cantilevers is demonstrated while being piezoelectrically actuated at its resonance frequency. The enhanced sensitivity is investigated by both theoretical analysis and experimental measurement of the vibration amplitude of the absorption mirror within a focal plane array, mounted on top of a piece of piezoelectric thin film and actuated at the resonance frequency of the thermal infrared imager. This work presents that the minimum detectable radiation power of an infrared photodiode is 0.02mW with the infrared imager under vibration at its resonance frequency. However, the same radiation power, 0.02mW or even a higher radiation power of the infrared photodiode cannot be detected without piezoelectric actuation with all the other experimental conditions unchanged. The proposed sensitivity enhancement approach is feasible for the infrared imagers with the output signals generated from their structural motion.
Bottom- and top-gate field-effect thin-film transistors with p channels of sintered HgTe nanocrystals
Authors: Kim Hyunsuk , Cho Kyoungah , Kim Dong-Won , Lee Hye-Ryoung , Kim Sangsig
Published: October 2006

Sintered HgTe nanocrystal-based thin-film transistors (TFTs) with bottom- and top-gate geometries were fabricated at a temperature of 150°C by spin coating in this work. The SiO2 bottom- and Al2O3 top-gate field-effect TFTs with p channels composed of sintered HgTe nanocrystals exhibit high carrier mobilities of 0.82 and 2.38cm2∕Vs, respectively. The operating gate voltages for the top-gate transistor with an Al2O3 dielectric layer are actually lower, compared with the SiO2 bottom-gate transistor. The electrical characteristics of these TFTs are discussed in more detail in this letter.
Planarized SiNx/spin-on-glass photonic crystal organic light-emitting diodes
Authors: Kim Yoon-Chang , Cho Sang-Hwan , Song Young-Woo , Lee Yong-Jae , Lee Yong-Hee , Do Young Rag
Published: October 2006

The light extraction characteristics of low-index spin-on-glass (SOG)-assisted, planarized photonic crystal organic light-emitting diodes (PC OLEDs) are reported. The light extraction efficiencies of planarized two-dimensional (2D) SiNx∕SOG PC OLEDs (type II) and 2D SiNx∕SOG PC OLEDs with an additional high-index SiNx layer (type III) are significantly better under typical operating conditions than those of the first generation of 2D SiO2∕SiNx PC OLEDs (type I). The enhancements in the extraction efficiencies of type-II and type-III PC OLEDs are about 63% and 85%, respectively, with respect to those of conventional OLEDs with indium tin oxide layers of identical thicknesses. These improvements in extraction efficiencies are attributed not only to the liberation of the photons trapped in the high-index guiding layer but also to a reduction in the surface plasmon contribution.
Low leakage p-NiO∕i-ZnO∕n-ITO heterostructure ultraviolet sensor
Authors: Vygranenko Yuriy , Wang Kai , Nathan Arokia
Published: October 2006

This letter reports a low leakage p-NiO∕i-ZnO∕n-ITO ultraviolet photodiode fabricated at room temperature by ion beam assisted e-beam evaporation. Analysis of its J-V characteristics, and time-dependent behavior, reveals that the dominant source of leakage current stems from deep defect states in the ZnO i layer, with its dynamic response at low signal levels limited by charge trapping in the absorption layer. Under a 5V reverse bias, the dark current density is 10nA∕cm2 and quantum efficiency is 18% at a wavelength of 380nm, with a photoresponse behavior that is linear over 5decades.
Subwavelength and super-resolution nondiffraction beam
Authors: Wang Haifeng , Shi Luping , Yuan Gaoqiang , Miao X. S. , Tan Weilian , Chong Towchong
Published: October 2006

A light spot that is smaller than a half wavelength will subsequently diverge in all directions. In this letter, the authors model a subwavelength (0.42λ) super-resolution light beam which propagates over a long distance without any divergence. This can be achieved by placing a multibelt pure-phase-type binary optical element on the lens pupil. The authors also report a useful approach for designing the optical element, based on vector diffraction theory, which can be used in paraxial and nonparaxial focusing and imaging systems.
Four-wave mixing and modulation instability of continuous optical waves in single-mode optical fibers
Authors: Liu Shanliang
Published: October 2006

The four-wave mixing (FWM) equations in single-mode fibers are investigated. It is found that there are four types of FWM, two of them are well known and the others have been known little. FWM can lead to modulation instability (MI) of continuous optical waves. The perturbations will rapidly be amplified and become stronger than the pump waves due to FWM. The characteristics of MI induced by different types of FWM are analyzed by numerically solving the FWM equations.
Spherical carbon particle growth in a methane plasma
Authors: Shoji Fumiya , Feng Zongbao , Kono Akihiko , Nagai Tatsuzo
Published: October 2006

There is strong evidence that the spherical carbon particles composed of graphite carbon onions of ca. 10nm are grown to micron size under the conditions of a heated Si (100) substrate surface exposed to irradiation by a CH4∕Ar plasma. Furthermore, it is described that these carbon particles of micron size are spherically grown in the plasma and then fall to the substrate surface.
Soft x-ray absorption spectroscopy of strained epitaxial manganite thin films
Authors: Valencia S. , Gaupp A. , Gudat W. , Abad Ll. , Balcells Ll. , Martínez B. , Laukhin V.
Published: October 2006

The O K-edge pre-edge structure in the x-ray absorption spectra of high quality La2∕3Ca1∕3MnO3 epitaxial thin films grown on top of (001) SrTiO3 and NdGaO3 substrates is analyzed as a function of structural strain and temperature. A clear correlation between temperature dependent spectral changes and the structural strain, induced by the film/substrate mismatch, is found.