bluuebunny/crossref_metadata_2025_split huggingface dataset:
A sub‐1V supply CMOS voltage reference generator
Authors: Tsitouras A. , Plessas F. , Birbas M. , Kikidis J. , Kalivas G. 
Published: February 2011

SUMMARYAn integrated sub‐1V voltage reference generator, designed in standard 90‐nm CMOS technology, is presented in this paper. The proposed voltage reference circuit consists of a conventional bandgap core based on the use of p‐n‐p substrate vertical bipolar devices and a voltage‐to‐current converter. The former produces a current with a positive temperature coefficient (TC), whereas the latter translates the emitter‐base voltage of the core p‐n‐p bipolar device to a current with a negative TC. The circuit includes two operational amplifiers with a rail‐to‐rail output stage for enabling stable and robust operation overall process and supply voltage variations while it employs a total resistance of less than 600 K Ω. Detailed analysis is presented to demonstrate that the proposed circuit technique enables die area reduction. The presented voltage reference generator exhibits a PSRR of 52.78 dB and a TC of 23.66ppm/∘C in the range of − 40 and 125∘C at the typical corner case at 1 V. The output reference voltage of 510 mV achieves a total absolute variation of ± 3.3% overall process and supply voltage variations and a total standard deviation, σ, of 4.5 mV, respectively, in the temperature range of − 36 and 125∘C. Copyright © 2011 John Wiley & Sons, Ltd.
Growth of the Initial Atomic Layers of Ta‐N Films During Atomic Layer Deposition on Silicon‐Based Substrates
Authors: Strehle Steffen , Schmidt Daniela , Albert Matthias , Bartha Johann W. 
Published: February 2011

AbstractThe growth of ultra‐thin Ta‐N films using atomic layer deposition (ALD) is investigated by in‐situ X‐ray photoelectron spectroscopy (XPS) starting from the first precursor pulse, as precursor substances tert‐butylimido‐tris(diethylamido)tantalum (TBTDET) and tert‐butylimido‐bis(diethylamido)cyclopentadienyl)tantalum (TBDETCp) are applied mainly on SiOH and SiH surfaces. The chemical composition, the growth mode, and the film thickness are derived as functions of the cycle number and the substrate chemistry. The growth rates are significantly higher on SiOH than on SiH substrates, which is related to the oxygen surface concentration. The film composition changes with the cycle number but stabilizes at an approximate stoichiometry of Ta2N2O for both precursors.
Observation of Structure‐Sensitive Decomposition of Cp(allyl)Pd on Pd Nanodots Formed by MOCVD
Authors: Binder Axel , Seipenbusch Martin , Kasper Gerhard 
Published: February 2011

AbstractThe decomposition kinetics of the organometallic precursor cyclopentadienyl‐allyl‐Pd [Cp(allyl)Pd] on silica and titania substrates (as well as previously deposited Pd) are investigated by continuous metal‐organic (MO)CVD under atmospheric pressure. The substrate particles are freshly generated in an aerosol process with well‐defined and known densities of surface OH groups, and then coated immediately in a second reactor. Time‐resolved data on size and number density of deposited Pd nanodots on the carrier particles are obtained by electron microscopy and used as a means to infer the decomposition kinetics. It is found that decomposition proceeds very rapidly for a few seconds, both by proton‐initiated decomposition on surface OH groups and by autocatalysis, until the Pd nanodots have grown to a size of about 2 nm, where autocatalysis comes to a standstill, regardless of precursor concentration, residence time in the CVD reactor, or decomposition temperature. Proton‐initiated decomposition on OH groups continues to depend measurably on these process parameters in terms of the number density of Pd dots, even after autocatalysis has stopped. Our observations indicate that autocatalysis is structure‐sensitive.
MC‐CDMA MIMO systems with quasi‐orthogonal space–time block codes: Channel estimation and multiuser detection
Authors: Yu Jung‐Lang , Wu Chun‐Hsien , Lee Ming‐Feng 
Published: February 2011

SUMMARYThis paper investigates blind channel estimation and multiuser detection for quasi‐synchronous multi‐carrier code‐division multiple‐access (MC‐CDMA) multiple‐input multiple‐output (MIMO) systems with quasi‐orthogonal space–time block codes (QO‐STBC). Subspace‐based blind channel estimation is proposed by considering a QO‐STBC scheme that involves four transmit antennas and multiple receive antennas. Based on the first‐order perturbation theory, the mean square error of the channel estimation is derived. With the estimated channel coefficients, we employ minimum output energy and eigenspace receivers for symbol detection. Using the QO‐STBC coding property, the weight analyses are performed to reduce the computational complexity of the system. In addition, the forward–backward averaging technique is presented to enhance the performance of multiuser detection. Numerical simulations are given to demonstrate the superiority of the proposed channel estimation methods and symbol detection techniques. Copyright © 2011 John Wiley & Sons, Ltd.
Bandwidth efficient asymmetric fingerprinting scheme
Authors: Hu Defa , Li Qiaoliang 
Published: February 2011

SUMMARYIn asymmetric fingerprinting, the merchant can trace the traitors from a pirated multimedia content copy by means of the embedded unique fingerprint, while the customer is immune of being framed due to the asymmetric property. The existing schemes are inefficient in practice due to their high bandwidth usage. This paper proposes an asymmetric fingerprinting scheme that is efficient from the bandwidth usage point of view. First, multicast an efficient transport technology for one‐to‐many communication is exploited, which can reduce the bandwidth usage significantly. Second, symmetric encryption instead of public‐key encryption is performed on the multimedia content, which can also reduce the complexity and communication cost. Copyright © 2011 John Wiley & Sons, Ltd.
Generation of a conditional null allele of Lbx1
Authors: Watanabe Shuichi , Matsushita Shoko , Hayasaka Michiko , Hanaoka Kazunori 
Published: February 2011

AbstractThe homeobox gene Lbx1 not only plays critical roles in myogenesis and neurogenesis during embryonic development but is also expressed in activated satellite cells of adult mice. To address the potential postnatal functions of Lbx1, we generated conditional Lbx1‐null mice using the Cre‐loxP system. We generated a mouse in which Exon 2 of Lbx1 was floxed (Lbx1flox/flox), followed by cross‐breeding between the Lbx1flox/flox mouse and either a transgenic mouse where a tamoxifen‐inducible Cre‐recombinase (Cre) was ubiquitously expressed, or a Myf5Cre mouse where Cre was inserted into the Myf5 locus. In both Lbx1‐null mouse lines generated, Pax3‐expressing limb muscle precursor cells were seriously reduced during embryonic development and eventually the limb extensor muscles were lost after birth. Since the conditional Lbx1‐null mice generated were viable for a prolonged time, they will be useful in the investigation of Lbx1 function throughout the lifespan of the mouse. genesis 49:803–810, 2011. © 2011 Wiley‐Liss, Inc.
Sub‐optimal CD4+ T‐cell activation triggers autonomous TGF‐β‐dependent conversion to Foxp3+ regulatory T cells
Authors: Oliveira Vanessa G. , Caridade Marta , Paiva Ricardo S. , Demengeot Jocelyne , Graca Luis 
Published: February 2011

AbstractClassical in vitro Treg conversion assays, which rely on optimal T‐cell activation in the presence of exogenous TGF‐β, induce Foxp3 expression at a frequency far above that which is observed in vivo in Treg‐dependent models of oral or transplantation tolerance. We have found that suboptimal murine T‐cell activation in vitro results in induction of Foxp3 expression, in the absence of exogenous TGF‐β, at a frequency similar to that which we found in vivo upon anti‐CD4‐induced transplantation tolerance. We show that TCR triggering with either low‐dose anti‐CD3 or low‐dose agonist peptide, as well as down‐modulation of the TCR signal with non‐depleting anti‐CD4, promotes TGF‐β production by T cells, an event that precedes Foxp3 expression and is Foxp3 independent. These findings support the view that sub‐immunogenic regimens lead to dominant tolerance as a result of T‐cell intrinsic properties.
Chemokine receptor CX3CR1 promotes dendritic cell development under steady‐state conditions
Authors: Łyszkiewicz Marcin , Witzlau Katrin , Pommerencke Jens , Krueger Andreas 
Published: February 2011

AbstractExpression of CX3CR1 is an attribute of myeloid precursors committed to the monocyte/macrophage (Mφ)/DC lineages and is maintained during all stages of DC differentiation. Nevertheless, the exact role of this molecule during developmental progression of myeloid precursors towards the DC lineage remains elusive. To overcome potential compensatory mechanisms and issues of redundancy, we employed competitive adoptive transfer experiments to assess a possible function of CX3CR1 in DC and monocyte/Mφ differentiation in vivo. We show here that expression of CX3CR1 promotes the generation of DCs and monocytes/Mφ under steady‐state conditions and during compensatory expansion after selective depletion of DCs, but not under inflammatory conditions evoked by sub‐lethal irradiation. Direct administration of CX3CR1‐deficient and CX3CR1‐sufficient precursors into the spleen or the thymus resulted in a similar competitive advantage of WT over CX3CR1‐deficient precursors as i.v. transfer, suggesting that CX3CR1‐mediated survival rather than recruitment to lymphoid organs is critical for DC/Mφ differentiation. In conclusion, our data support the hypothesis that CX3CR1 promotes proper development of myeloid precursors into DCs and monocytes/Mφs under steady‐state conditions, possibly by providing survival signals or mediating accessibility to organ‐specific niches, rather than acting as a mediator of homing to the spleen or the thymus.
TCR‐like antibodies distinguish conformational and functional differences in two‐ versus four‐domain auto reactive MHC class II–peptide complexes
Authors: Dahan Rony , Tabul Moran , Chou Yuan K. , Meza‐Romero Roberto , Andrew Shayne , Ferro Adolph J. , Burrows Gregory G. , Offner Halina , Vandenbark Arthur A. , Reiter Yoram 
Published: February 2011

AbstractAntigen‐presenting cell‐associated four‐domain MHC class II (MHC‐II) molecules play a central role in activating autoreactive CD4+ T cells involved in multiple sclerosis (MS) and type 1 diabetes (T1D). In contrast, two‐domain MHC‐II structures with the same covalently attached self‐peptide (recombinant T‐cell receptor ligands (RTLs)) can regulate pathogenic CD4+ T cells and reverse clinical signs of experimental autoimmune diseases. RTL1000, which is composed of the β1α1 domains of human leukocyte antigen (HLA)‐DR2 linked to the encephalitogenic human myelin oligodendrocyte glycoprotein (MOG)‐35‐55 peptide, was recently shown to be safe and well tolerated in a phase I clinical trial in MS. To evaluate the opposing biological effects of four‐ versus two‐domain MHC‐II structures, we screened phage Fab antibodies (Abs) for the neutralizing activity of RTL1000. Five different TCR‐like Abs were identified that could distinguish between the two‐ versus four‐domain MHC–peptide complexes while the cognate TCR was unable to make such a distinction. Moreover, Fab detection of native two‐domain HLA‐DR structures in human plasma implies that there are naturally occurring regulatory MHC–peptide complexes. These results demonstrate for the first time distinct conformational determinants characteristic of activating versus tolerogenic MHC–peptide complexes involved in human autoimmunity.
Role of CLIC4 in the host innate responses to bacterial lipopolysaccharide
Authors: He Guoan , Ma Yao , Chou Szu‐Yi , Li Huihong , Yang Chingwen , Chuang Jen‐Zen , Sung Ching‐Hwa , Ding Aihao 
Published: February 2011

AbstractChloride intracellular channel (CLIC) 4 has diverse functions in membrane trafficking, apoptosis, angiogenesis and cell differentiation. CLIC4 is abundantly expressed in macrophages, but its role in innate immune functions is unclear. Here, we show that primary murine macrophages express increased amounts of CLIC4 after exposure to bacterial lipopolysaccharide (LPS). Endogenous CLIC4 level was significantly elevated in the brain, heart, lung, kidney, liver and spleen after LPS injection of mice. Stable macrophage lines overexpressing CLIC4 produced more TNF, IL‐6, IL‐12 and CCL5 than mock transfectants when exposed to LPS. To explore the role of CLIC4 in vivo, we generated CLIC4‐null mice. These mice were protected from LPS‐induced death, and had reduced serum levels of inflammatory cytokines. Upon infection with Listeria monocytogenes, CLIC4‐deficient mice were impaired in their ability to clear infection, and their macrophages responded to Listeria by producing less inflammatory cytokines and chemokines than the WT controls. When challenged with LPS in vitro, deletion of clic4 gene had little effect on MAPK and NF‐κB activation, but led to a reduced accumulation of phosphorylated interferon response factor 3 (IRF3) within macrophages. Conversely, overexpression of CLIC4 enhanced LPS‐mediated IRF3. Thus, these findings suggest that CLIC4 is an LPS‐induced product that can serve as a positive regulator of LPS signaling.
A Rare μ4‐O Centred Dy4 Tetrahedron with Coordination‐Induced Local Chirality and Single‐Molecule Magnet Behaviour
Authors: Lin Po‐Heng , Korobkov Ilia , Wernsdorfer Wolfgang , Ungur Liviu , Chibotaru Liviu F. , Murugesu Muralee 
Published: February 2011

AbstractCoordination‐induced chirality was achieved in a uniquetetrahedral [Dy4(μ4‐O)(μ‐OMe)2(beh)2(esh)4]·3MeOH complex through a twisted diazine bridge from a Schiff base ligand. Magnetic measurements reveal weak intramolecular antiferromagnetic interactions (J = –0.3 cm–1) with single‐molecule magnet behaviour (Ueff = 23.42 K).
Argan oil and other argan products: Use in dermocosmetology
Authors: Guillaume Dominique , Charrouf Zoubida 
Published: February 2011

AbstractArgan oil is of food or cosmetic (INCI name: Argania spinosa kernel oil) grade. During the past 15 years cosmetic argan oil, as beauty oil or cosmetic ingredient, has become one of the major actors in the dermocosmetic field. Beauty argan oil is produced by cold‐pressing argan‐fruit kernels. As a cosmetic ingredient, argan oil is produced by solvent‐assisted extraction of the finely crushed kernels. Enriched‐argan oil which is produced by distillation of cosmetic argan oil can be supplemented with antioxidants. Hence, it presents an even better cosmetic potential. Argan fruit pulp and argan leaves also contain proteins, peptides, saponins and other chemicals presenting highly interesting dermocosmetics. Therefore, the argan tree (A. spinosa) is sometimes nicknamed A. cosmetosa. We comprehensively review the current knowledge (literature and patent) related to argan oil and argan tree products in the dermocosmetic domain.
Enantioselective Conjugate Addition of Malononitrile to Chalcones Promoted by α,α‐L‐Diaryl Prolinols: Noncovalent versus Covalent Catalysis?
Authors: Russo Alessio , Capobianco Amedeo , Perfetto Alessandra , Lattanzi Alessandra , Peluso Andrea 
Published: February 2011

AbstractThe enantioselective conjugate addition of malononitrile to trans‐chalcones has been investigated as a case study using easily available α,α‐L‐diaryl prolinols as promoters. Both experimental and computational results are consistent with a bifunctional noncovalent mode of activation of the reactive partners, provided by the secondary amine and hydroxyl groups of the promoter as general base and acid catalysis. This most energetically affordable pathway predicts predominant formation of the R‐configured adducts, which is in agreement with the experimental findings. The present study addresses, for the first time, the ability of proline derivatives to assist product formation through noncovalent catalysis, in analogy to the mode of action typically recognized for Cinchona alkaloids.
Magnetically Separable and Reusable Copper Ferrite Nanoparticles for Cross‐Coupling of Aryl Halides with Diphenyl Diselenide
Authors: Swapna Kokkirala , Murthy Sabbavarapu Narayana , Nageswar Yadavalli Venkata Durga 
Published: February 2011

AbstractA simple and efficient procedure for the synthesis of diaryl selenides has been developed by a copper ferrite nanoparticle catalyzed reaction of aryl iodides/aryl bromides with diphenyl diselenide in the presence of base and solvent at 120 °C. Using this protocol, a variety of diselenides were obtained in good to excellent yields. The copper ferrite nanoparticles were magnetically separated, recycled, and reused up to three cycles.
Macrocycle or Cage? The Presence or Absence of Ca2+ Template Ions Controls the Equilibrium in an Oligoimine Dynamic Combinatorial Library
Authors: Schleef Frank , Lüning Ulrich 
Published: February 2011

AbstractA dynamic combinatorial library (DCL) was formed by mixing the triamine 1 and the diamine 3 with the pyridine‐2,6‐dicarbaldehyde 2 (R = OMe). In the absence of any template ion, the bimacrocyclic cage 4 (R = OMe) derived from the triamine 1 formed nicely whereas the monomacrocycle 5 (R = OMe) originating from the diamine 3 was only formed in small amounts (product ratio, after reduction: [6]/[7] = 4.3:1). Addition of calcium ions reversed the product ratio ([6]/[7] = 1:17).
Easy‐to‐Execute Carbonylative Arylation of Aryl Halides using Molybdenum Hexacarbonyl: Efficient Synthesis of Unsymmetrical Diaryl Ketones
Authors: Jafarpour Farnaz , Rashidi‐Ranjbar Parviz. , Kashani Asieh Otaredi 
Published: February 2011

AbstractA versatile procedure for the synthesis of unsymmetrical diaryl ketones through a palladium‐catalyzed carbonylative arylation of iodoarenes through easy‐to‐handle molybdenum hexacarbonyl as a condensed source of carbon monoxide is described. This method provides an efficient route to a wide variety of substituted diaryl ketones without direct use of high‐pressure carbon monoxide.
The extended N2 method taking into account higher mode effects in elevation
Authors: Kreslin Maja , Fajfar Peter 
Published: February 2011

AbstractThe N2 method has been extended in order to take into account higher mode effects in elevation. The extension is based on the assumption that the structure remains in the elastic range when vibrating in higher modes. The seismic demand in terms of displacements and storey drifts can be obtained by enveloping the results of basic pushover analysis and the results of standard elastic modal analysis. The approach is consistent with the extended N2 method used for plan‐asymmetric buildings. The proposed procedure was applied to three variants of three steel frame buildings used in the SAC project. The structural response was investigated for two sets of ground motions. Different ground motion intensities were used in order to investigate the influence of the magnitude of plastic deformations. The N2 results were compared with the results of nonlinear response‐history analysis, two other pushover‐based methods (modal pushover analysis (MPA) and modified MPA (MMPA)), and pushover analysis without consideration of higher modes. It was found that a considerable influence of higher modes on storey drifts is present at the upper part of medium‐and high‐rise structures. This effect is the largest in the case of elastic behaviour and decreases with ground motion intensity. The higher mode effects also depend on the spectral shape. The approximate methods (extended N2, MPA and MMPA) are able to provide fair estimates of response in the case of the test examples. Accuracy decreases with the height of the building, and with the intensity of ground motion. The N2 results are generally conservative. Copyright © 2011 John Wiley & Sons, Ltd.
Theory and experimental study for sliding isolators with variable curvature
Authors: Lu Lyan‐Ywan , Lee Tzu‐Ying , Yeh Shih‐Wei 
Published: February 2011

AbstractBecause a conventional isolation system with constant isolation frequency is usually a long‐period dynamic system, its seismic response is likely to be amplified in earthquakes with strong long‐period wave components, such as near‐fault ground motions. Seismic isolators with variable mechanical properties may provide a promising solution to alleviate this problem. To this end, in this work sliding isolators with variable curvature (SIVC) were studied experimentally. An SIVC isolator is similar to a friction pendulum system (FPS) isolator, except that its sliding surface has variable curvature rather being spherical. As a result, the SIVC's isolation stiffness that is proportional to the curvature becomes a function of the isolator displacement. By appropriately designing the geometry of the sliding surface, the SIVC is able to possess favorable hysteretic behavior. In order to prove the applicability of the SIVC concept, several prototype SIVC isolators, whose sliding surfaces are defined by a sixth‐order polynomial function, were fabricated and tested in this study. A cyclic element test on the prototype SIVC isolators and a shaking table test on an SIVC isolated steel frame were all conducted. The results of both tests have verified that the prototype SIVC isolators do indeed have the hysteretic property of variable stiffness as prescribed by the derived formulas in this study. Moreover, it is also demonstrated that the proposed SIVC is able to effectively reduce the isolator drift in a near‐fault earthquake with strong long‐period components, as compared with that of an FPS system with the same friction coefficient. Copyright © 2011 John Wiley & Sons, Ltd.
Comparing landscape evolution models with quantitative field data at the millennial time scale in the Belgian loess belt
Authors: Temme A. J. A. M. , Peeters I. , Buis E. , Veldkamp A. , Govers G. 
Published: February 2011

ABSTRACTThis study compares three landscape evolution models and their ability to correctly simulate measured 2500 year landscape evolution in two small catchments in the Belgian loess belt. WATEM LT and LAPSUS both model tillage and water erosion and deposition and have detachment‐limited descriptions for water erosion and deposition. Equations in LAPSUS are more mechanistic than those in WATEM LT. WATEM LTT resembles WATEM LT, but is a transport‐limited model. All three models are DEM‐based. Calibration and validation simulations were performed forward in time on (1D) transects for four spatial resolutions, and backward in time for (2D) catchments at 20 m resolution. For transects, model outputs were compared with discretized observations of transect shape. For catchments, outputs were compared with point observations of palaeo‐altitude, averaged over landscape element classes. For transects, the three models performed well, resulting in model efficiency factors of 0.92 to 0.99 for calibration and 0.62 to 0.96 for validation. However, for catchments, simulations showed that the transport‐limited WATEM LTT model could not realistically simulate long‐term landscape evolution. Performance of WATEM LT and LAPSUS at catchment scale was similar to that on transects, although LAPSUS has problems with backward calculation. Tests demonstrate that a transport‐limited approach cannot be used to model long‐term landscape evolution in the Belgian loess belt, which is in agreement with theoretical and empirical understanding of soil erosion processes in this environment. The difference in performance between transport‐limited and detachment‐limited models is clear only when the models are evaluated in a 2D catchment. The lack of such distinction when models were applied in a 1D transect highlights the importance of evaluating landscape evolution models in a 2D setting so that effects of flow convergence/divergence can be accounted for. Copyright © 2011 John Wiley & Sons, Ltd.