bluuebunny/crossref_metadata_2025_split huggingface dataset:
Report of resistance to the neonicotinoid insecticide imidacloprid in Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)
Authors: Gorman Kevin , Devine Gregor , Bennison Jude , Coussons Peter , Punchard Neville , Denholm Ian 
Published: April 2007

AbstractSusceptibilities of UK and mainland European samples of Trialeurodes vaporariorum (Westwood) to the neonicotinoid insecticide imidacloprid were investigated over a 7 year period. All 24 strains collected between 1997 and 2003 showed similar baseline levels of susceptibility to that of a known susceptible laboratory strain when exposed to a diagnostic concentration (128 mg L−1) of formulated imidacloprid. Two samples collected during 2004, one from the UK and one from The Netherlands, demonstrated reduced susceptibility at this concentration. Using dose–response assays, the presence of resistant individuals was disclosed in both these strains; some individuals were unaffected at doses high enough to induce phytotoxic effects. This report represents the first confirmed cases of neonicotinoid resistance inducing control failures in T. vaporariorum, and highlights a need for careful vigilance to sustain the effectiveness of imidacloprid and related neonicotinoid insecticides. Copyright © 2007 Society of Chemical Industry
Impact of a Turkish isolate and a plaque‐purified variant of SpliNPV‐B on larval stage development ofSpodoptera littoralis(Lepidoptera: Noctuidae) Boisd
Authors: Toprak Umut , Gürkan M Oktay , Bayram Şerife 
Published: April 2007

AbstractBaculoviruses can alter the development and physiological status of their insect hosts. In the present study, twoSpodoptera littoralisnucleopolyhedroviruses (SpliNPV‐TR1 and SpliNPV‐M2) were examined in terms of their effect on the stage development ofS. littoralisat two doses/concentrations by inoculation of neonates or third instars. Both isolates had an acute pathological effect on neonates. However, larval development was prolonged (6–36 h) by either infection when neonates were infected. When third‐instar larvae were inoculated, no mortality occurred until insects moulted to later stages. When the isolates were compared, more mortality occurred in the fifth instar with SpliNPV‐M2 than with SpliNPV‐TR1, whereas less mortality occurred in the sixth instar with SpliNPV‐M2 than with SpliNPV‐TR1. However, none of the isolates demonstrated a dose effect. Larvae died at 108–198 h post‐inoculation at all infections, and none of them pupated. Larval development was retarded (0–126 h) for each stage when third‐instar larvae were inoculated. Consequently, SpliNPV‐M2 would be a more effective control agent than SpliNPV‐TR1 for control ofS. littoralissince it kills larvae at earlier developmental stages. Copyright © 2007 Society of Chemical Industry
The use of Fmoc‐Lys(Pac)‐OH and penicillin G acylase in the preparation of novel semisynthetic insulin analogs
Authors: Žáková Lenka , Zyka Daniel , Ježek Jan , Hančlová Ivona , Šanda Miloslav , Brzozowski Andrzej M. , Jiráček Jiří 
Published: April 2007

AbstractIn this paper, we present the detailed synthetic protocol and characterization of Fmoc‐Lys(Pac)‐OH, its use for the preparation of octapeptides H‐Gly‐Phe‐Tyr‐N‐MePhe‐Thr‐Lys(Pac)‐Pro‐Thr‐OH and H‐Gly‐Phe‐Phe‐His‐Thr‐Pro‐Lys(Pac)‐Thr‐OH by solid‐phase synthesis, trypsin‐catalyzed condensation of these octapeptides with desoctapeptide(B23‐B30)‐insulin, and penicillin G acylase catalyzed cleavage of phenylacetyl (Pac) group fromNε‐amino group of lysine to give novel insulin analogs [TyrB25,N‐MePheB26,LysB28,ProB29]‐insulin and [HisB26]‐insulin. These new analogs display 4 and 78% binding affinity respectively to insulin receptor in rat adipose membranes. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Activity and stability of human kallikrein‐2‐specific linear and cyclic peptide inhibitors
Authors: Pakkala Miikka , Hekim Can , Soininen Pasi , Leinonen Jari , Koistinen Hannu , Weisell Janne , Stenman Ulf‐HÅkan , Vepsäläinen Jouko , Närvänen Ale 
Published: April 2007

AbstractHuman glandular kallikrein (KLK2) is a highly prostate‐specific serine protease, which is mainly excreted into the seminal fluid, but part of which is also secreted into circulation from prostatic tumors. Since the expression level of KLK2 is elevated in aggressive tumors and it has been suggested to mediate the metastasis of prostate cancer, inhibition of the proteolytic activity of KLK2 is of potential therapeutic value. We have previously identified several KLK2‐specific linear peptides by phage display technology. Two of its synthetic analogs, A R R P A P A P G (KLK2a) and G A A R F K V W W A A G (KLK2b), show specific inhibition of KLK2 but their sensitivity to proteolysis in vivo may restrict their potential use as therapeutic agents. In order to improve the stability of the linear peptides for in vivo use, we have prepared cyclic analogs and compared their biological activity and their structural stability. A series of cyclic variants with cysteine bridges were synthesized. Cyclization inactivated one peptide (KLK2a) and its derivatives, while the other peptide (KLK2b) and its derivatives remained active. Furthermore, backbone cyclization of KLK2b improved significantly the resistance against proteolysis by trypsin and human plasma. Nuclear magnetic resonance studies showed that cyclization of the KLK2b peptides does not make the structures more rigid. In conclusion, we have shown that backbone cyclization of KLK2 inhibitory peptides can be used to increase stability without losing biological activity. This should render the peptides more useful for in vivo applications, such as tumor imaging and prostate cancer targeting. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Urbach tail in the absorption spectra of 2H‐WSe2 layered crystals
Authors: Hu S. Y. , Lee Y. C. , Shen J. L. , Chen K. W. , Huang Y. S. 
Published: April 2007

AbstractUrbach's rule and steepness parameter of 2H‐WSe2 layered crystals have been studied via the absorption spectra from the photoconductivity (PC) measurements in the temperature range of 15–300 K. From the analysis of the temperature‐dependent band gap with Varshni semi‐empirical equation, the Debye temperature was estimated as 160 K while the Einstein temperature was around 125 K from the Einstein oscillator model. The effective phonon energy was estimated successfully from the temperature dependence of the Urbach energy extracted from the PC spectra and the value was found out to be well correlated to the active E1g mode observed in the Raman spectra of 2H‐WSe2. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical and micro‐analytical study of a copper–conjugated polymer composite
Authors: Mallick Kaushik , Witcomb Mike J. , Scurrell Mike S. 
Published: April 2007

AbstractAn oriented morphology of a conjugated polymer has been synthesized by using cupric sulfate as the oxidizing agent. A one pot, in‐situ chemical synthesis approach has been utilized in which cupric sulfate is reduced during the polymerization process and forms copper nanoparticles, which are evenly dispersed in the polymer fiber. The elemental identity of the nanoparticles was determined by means of EDX analyses and EELS mapping for the copper using analytical transmission electron microscopy (TEM). The TEM images at higher magnifications showed that the copper particles were highly dispersed throughout the polymer matrix. Optical properties of the polymer were studied by UV–vis, Infrared and Raman spectra analysis and provided information regarding the chemical structure of the polymer. A brief mechanistic approach regarding the formation of the fiber‐like metal‐polymer composite material is given. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nano‐ and macropores in the model for current oscillations at the Si/electrolyte contact
Authors: Grzanna J. , Jungblut H. , Lewerenz H. J. 
Published: April 2007

AbstractThe transition from sustained to damped current oscillations or to stationary behavior is described using a model based on morphological aspects. A roughening of the oxide and of the underlying Si surface is predicted, in accordance with measurements. The role of cracks and nanopores in silicon oxide is discussed with regard to roughness increase and macropore formation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrochemical formation of porous silica: toward an understanding of the mechanisms
Authors: Frey S. , Keipert S. , Chazalviel J.‐N. , Ozanam F. , Carstensen J. , Föll H. 
Published: April 2007

AbstractPorous silica may be formed by anodization of silicon in a neutral fluoride electrolyte. Applying a high potential leads to initiation of porous layer growth, which may be pursued at lower potentials. We have tried to improve our understanding of the growth process. Initiation of the growth appears to be caused by oxygen evolution, which leads to local acidification of the medium. In the steady state, ion depletion in the electrolyte may lead to the presence of a strong space charge. Experiments indicate that such a charged layer may represent at most a small fraction of the porous layer thickness. Theoretical estimates suggest that this effect may be neglected. A model, making use of the diffusion equations of the various species (H+, F–, HF, SiF62–), accounts for the current/potential curves and oxide layer thickness in a semiquantitative manner. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoelectrochemical texturization of n‐type multicrystalline silicon
Authors: Tena‐Zaera R. , Bastide S. , Lévy‐Clément C. 
Published: April 2007

AbstractTaking advantage of the electrochemical formation of macropores in aqueous HF under illumination, we have developed an efficient photoelectrochemical (PEC) texturization on n‐type multicrystalline Si (mc‐Si) wafers which leads to a decrease in the reflectivity of solar cells. An optimized mc‐Si texturized surface exhibits an 8.5% effective reflectivity (λ = 400–1000 nm, AM1.5 standard solar illumination). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scaleable synthesis route for silicon nanocrystal assemblies
Authors: Limaye S. , Subramanian S. , Goller B. , Diener J. , Kovalev D. 
Published: April 2007

AbstractWe report on a scaleable synthesis route for highly luminescent silicon nanocrystal assemblies and demonstrate that their emission properties are identical to those known for other systems containing silicon nanocrystals. Structural investigations confirmed that chemically porosified metallurgical grade silicon powder consists of silicon nanocrystal assemblies having nanometer sizes characterized by very high total internal surface area. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and photoluminescence properties of silicon nanowires treated by high‐pressure water vapor annealing
Authors: Salhi B. , Gelloz B. , Koshida N. , Patriarche G. , Boukherroub R. 
Published: April 2007

AbstractThis paper reports on silicon nanowires (SiNWs) growth on porous silicon (PS) template using vapor‐liquid‐solid (VLS) technique and the effect of high‐pressure water vapor annealing (HWA) on their optical properties. Gold nanoparticles (Au NPs) with average mean diameter of 50 and 20 nm were used as catalysts. The SiNWs were obtained by thermal decomposition of silane gas (SiH4) at high temperature (540 °C) catalyzed by the Au NPs. The resulting nanostructures display comparable diameter to the initial gold catalysts and are few microns long without a preferential growth direction. We have next examined the optical properties of the 20 nm diameter SiNWs. As‐prepared SiNWs display a weak photoluminescence (PL), which is related to the recombination emissions from defect centers. High‐pressure water vapor annealing (HWA) at 260 °C and 2.6 MPa of the SiNWs led to an increase of the PL by a factor 10 without significant changes in the emission band. TEM analysis of the HWA‐treated SiNWs showed a crystalline silicon core surrounded by an amorphous oxide layer. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Incorporation of hydrogen in porous silicon nanocrystallites
Authors: Lysenko V. , Alekseev S. , Botsoa J. , Barbier D. 
Published: April 2007

AbstractQuantitative measurements of hydrogen concentration in porous silicon (PS) nanostructures reveal hydrogen incorporation inside the silicon nanocrystallites constituting the porous layers. We propose a phenomenological model in which the main cause responsible for hydrogen incorporation is the plastic deformation of silicon nanocrystallites accompanying their formation during the electrochemical anodization of monocrystalline Si and resulting in partial rupture of Si–Si bonds. Nanocrystallite dimension and layer porosity influence this relaxation phenomenon resulting in different concentrations of the incorporated hydrogen. A particular effect of such phenomenon is the almost complete transformation of highly porous Si consisting of small nanoparticles in a binary solid composite constituted by Si and H atoms. The impact of hydrogen incorporation on the photoluminescent properties of PS nanostructures is discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Macropore growth in a prepatterned p‐type silicon wafer
Authors: Kobayashi K. , Harraz F. A. , Izuo S. , Sakka T. , Ogata Y. H. 
Published: April 2007

AbstractThe formation process of ordered macropores in a prepatterned p‐type silicon wafer was investigated. FE‐SEM observation focusing on the early stage of the pore growth clarified the two‐step process of macropore formation, whose first step was isotropic pore expansion from prepared etch pits and the second was anisotropic growth in the depth direction. Investigation using different etch‐pit patterns revealed that ordered macropores with constant diameters were obtained when the spacing of etch pits was 3–8 μm, while the spacing of 2 μm resulted in the pore‐wall collapse. The diameter and the wall thickness of macropores showed a tendency to decrease with decreasing the spacing of prepared etch pits, which could not be explained only from the width of the space‐charge region. The resistance distribution in a silicon substrate was proposed as a parameter playing a crucial role in determination of the wall thickness. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of confined macroporous silicon membranes on pre‐defined areas on the Si substrate
Authors: Pagonis D. N. , Nassiopoulou A. G. 
Published: April 2007

AbstractIn this work we investigated the formation of confined macroporous silicon membranes on pre‐defined areas on the silicon substrate. Two different cases were considered: a) membranes supported by the silicon substrate and b) membranes suspended over a cavity on Si. The confined areas were defined lithographically and porous silicon formation took place at mask openings. The main difficulty to overcome was to avoid trenching and silicon over‐etching at mask borders, related with the masking technology used. An appropriate masking technology was developed and used to fabricate a) single macroporous and b) bilayers of macroporous over mesoporous silicon. In the second case, by selectively removing the mesoporous layer, suspended confined macroporous silicon membranes over a cavity on the silicon substrate were fabricated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Brillouin light scattering from porous silicon films and multilayers
Authors: Andrews G. T. , Polomska A. M. , Vazsonyi E. , Volk J. 
Published: April 2007

AbstractPorous silicon films and multilayers were studied using Brillouin spectroscopy. Acoustic wave velocities and elastic constants were determined for films with porosity ∼0.60 formed from p–, p+ and n+ crystalline silicon. The velocities and elastic constants depend on the pore/crystallite geometry and morphology. Porous silicon multilayers were fabricated from (100) p+ crystalline silicon. For a multilayer with 250 nm layer thickness and layer porosity sequence of 0.45/0.65/0.45/0.65/0.45, the Rayleigh surface phonon velocity was found to be 2850 m/s. The origin(s) of other peaks in the multilayer spectra are unknown but it is unlikely that they are surface modes because their shift(s) are independent of incident angle. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pores growth control by in‐situ FFT impedance spectroscopy
Authors: Foca E. , Carstensen J. , Popkirov G. , Föll H. 
Published: April 2007

AbstractFast Fourier transform impedance electrochemical spectroscopy (FFT EIS) and photoelectrochemical impedance spectroscopy (FFT‐PEIS) have been used for the first time to characterize in‐situ the dynamics of macropore growth in n‐type Si under backside illumination. In the case of PEIS the illumination intensity was modulated and the response of the etching current (at constant voltage) was measured, thus an impedance‐like transfer function was obtained. A theoretical model taking into account the minority carrier diffusion in the semiconductor and the ion diffusion in the electrolyte successfully fit the impedance data from both EIS and PEIS. From the fit quantitative data, for example the pore depth or the diffusion length of the minority carriers, could be calculated in‐situ and in real time during the pore growth. The new technique can be used as feedback for active control in automated pore etching. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of metal wire arrays via electrodeposition in pores of Si, Ge and III–V semiconductors
Authors: Fang C. , Foca E. , Sirbu L. , Carstensen J. , Föll H. , Tiginyanu I. M. 
Published: April 2007

AbstractDeep straight macropores in n‐type Si have been completely filled with copper (Cu). Homogeneous metal deposition inside the deep pores was achieved by means of electroplating using a solution containing only CuSO4 mixed with H2SO4 and an optimized process that begins at the bottom of the pores. Pores as deep as 150 µm could be filled without encountering the so‐called “bottleneck” effect. Straight macropores with diameters below 100 nm and extreme aspect ratios in InP could be filled with Cu using a pulsed process. Interconnected pores extending in the available set of 〈111〉 directions in {100} GaAs and forming domains could not be filled with Cu; instead the volume occupied by the pore domain was completely filled with Cu; i.e. the porous structure was destroyed. A possible reason for this new effect will be given. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A simplified biomolecule attachment strategy for biosensing using a porous Si oxide interferometer
Authors: Perelman Loren A. , Schwartz Michael P. , Wohlrab Aaron M. , VanNieuwenhze Michael S. , Sailor Michael J. 
Published: April 2007

AbstractA simple strategy for linking biomolecules to porous Si surfaces and detecting peptide/drug binding is described. Porous Si is prepared using an electrochemical etch and then thermally oxidized by heating in ambient atmosphere. Bovine serum albumin (BSA) is then non‐covalently adsorbed to the inner pore walls of the porous Si oxide (PSiO2) matrix. The BSA layer is used as a linker for covalent attachment of the peptide Ac‐L‐Lysine‐D‐Alanine‐D‐Alanine (KAA) using published bioconjugation chemistry. BSA‐coated surfaces functionalized with KAA display specificity for the glycopeptide vancomycin while resisting adsorption of non‐specific reagents. While the biomolecule attachment strategy reported here is used to bind peptides, the scheme can be generalized to the linking of any primary amine‐containing molecule to PSiO2 surfaces. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanostructures and porous silicon: activity at interfaces in sensors and photocatalytic reactors
Authors: Gole James L. , Lewis Stephen , Lee Seungwoo 
Published: April 2007

AbstractNanopore covered microporous porous silicon (PS) interfaces have been formed to provide an active scaffolding for the creation of sensor and microreactor configurations. Rapidly responding (≤2s), reversible, and sensitive (≤2 ppm), PS gas sensors, operating at room temperature, and based on a uniquely formed highly efficient electrical contract to the nanopore covered microporous array, are modified by introducing active nanoparticles to establish gas selectivity. In a complementary manner, active sites can be introduced for the purpose of forming a nanostructure based microreactor. Pulsing techniques and FFT analysis allow the gas response of the sensors to be measured, without saturation, and filtered on a drifting baseline to eliminate false positives and the effects of external noise. TiO2–x N x visible light absorbing photocatalysts are introduced to quartz surfaces and to the PS structure for the purpose of creating a microreactor and subsequently to form the preconditioner for a solar pumped sensor. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An integrated pressure‐driven microsystem based on porous silicon for optical monitoring of gaseous and liquid substances
Authors: De Stefano L. , Alfieri D. , Rea I. , Rotiroti L. , Malecki K. , Moretti L. , Della Corte F. G. , Rendina I. 
Published: April 2007

AbstractIn this communication, the design and the fabrication of a silicon‐glass microsystem for lab‐on‐chip sensing applications have been reported. Each component has been realised using wet etch process and the porous silicon (PSi) technology, while the final device has been obtained intimately joining all elements by the Anodic Bonding (AB) process. The flow injection analysis (FIA) principle has been adopted in the microfluidic manipulation of the analyte samples: very small volume of the substances can be quickly and repeatedly monitored. The transducer element of the sensor device is a PSi Fabry–Perot monolayer which allows a very effective interaction with several chemicals and biological molecules. Time resolved measurements revealed very rapid response times in detecting some volatile substances. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New transport phenomena probed by dielectric spectroscopy of oxidized and non‐oxidized porous silicon
Authors: Urbach B. , Axelrod E. , Sa'ar A. 
Published: April 2007

AbstractDielectric spectroscopy accompanied by infrared (IR) and photoluminescence (PL) spectroscopy have been utilized to reveal the correlation between transport, optical and structural properties of oxidized porous silicon (PS). Three relaxation processes at low‐, mid‐ and high‐temperatures were observed, including dc‐conductivity at high‐temperatures. Both the low‐T relaxation and the dc conductivity were found to be thermally activated processes that invlove tunneling and hopping in between the nanocrystals in oxidized PS. We have found that the dc‐conductivity is limited by geometrical constrictions along the transport channels, which are not effected by the oxidation process and are characterized by activation energis of about ∼0.85 eV. The low‐T relaxation process involves thermal activation followed by tunneling in between neighbor nanocrystals, with somewhat lower activation energies. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous silica–laser dye composite: physical and optical properties
Authors: Chouket A. , Elhouichet H. , Boukherroub R. , Oueslati M. 
Published: April 2007

AbstractThe optical properties of rhodamine B dye molecules confined in porous silica are reported. Porous silica–laser dye composite is obtained by simple impregnation of porous silica (PS) in rhodamine B (RhB) solution. The FTIR spectroscopy shows penetration of rhodamine molecules in the matrix. A nonradiative excitation transfer due to dipolar interaction is evidenced from the effect of the RhB concentration on the PL emission and confirmed by FTIR spectroscopy. It was found that the formed composite displays an efficient and stable PL. An anti‐Stokes emission is observed and its origin is attributed to chemical species interactions with one photon absorption. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)