bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comprehensive Investigation of Catalyst Structure and Polymerization Conditions for Chain Branching in Ethylene Polymerization with Phillips‐Type Catalysts
Authors: Tonosaki Kiwamu , Taniike Toshiaki , Terano Minoru 
Published: January 2011

AbstractControl factors of branching in ethylene polymerization on CrOx/SiO2 catalysts were comprehensively investigated by varying catalyst structure and polymerization conditions. Variation of the polymerization conditions such as polymerization time, catalyst concentration, polymerization temperature, and alkylaluminum concentration indicated that the branch frequencies in produced polyethylene were highly relevant to the polymerization yield, plausibly through concentration of in‐situ‐produced α‐olefins. A method to fairly compare the branching abilities of different catalysts was proposed. The application of the method to model catalysts with controlled chromium nuclearity proved an important role of dinuclear species in methyl branching through olefin metathesis. magnified image
Macro electromyography and motor unit number index in the tibialis anterior muscle: Differences and similarities in characterizing motor unit properties in prior polio
Authors: Sandberg Arne , Nandedkar Sanjeev D. , Stålberg Erik 
Published: January 2011

AbstractOur objective was to establish the usefulness of the noninvasive method of the motor unit number index (MUNIX) in a large muscle and to study how macro electromyography (EMG) and MUNIX complement each other in describing the motor units (MUs) in prior polio. MUNIX and macro EMG were performed in 48 tibialis anterior muscles in 33 prior polio patients. In addition, the reproducibility of MUNIX was investigated. It is shown that MUNIX can be used to characterize MUs with high reproducibility, even in a large muscle. As judged by MUNIX values, the patients had a 25% reduction of motor neurons, whereas the macro EMG indicated a loss of 60% of the neurons. Macro EMG showed more pronounced changes compared with control material than the MUNIX. One of the reasons for this finding may be the difference in MU populations studied with the two methods. Muscle Nerve, 2011
How well informed are women who undergo urodynamic testing?
Authors: Neustaedter E. Grace , Milne Jill , Shorten Kathleen , Weckman Betty , Tse Angela , Tange Selphee 
Published: January 2011

AbstractAimsUrodynamic studies (UDS) are complex, invasive and may be emotionally and physically distressing. Inadequate information may heighten distress. Prior to UDS, our patients receive written and verbal information, yet concerns remains that some women may not be adequately informed. This study examined how informed women believe they are to undergo UDS in our clinic.MethodsThis was a before–after questionnaire‐based study. Data were collected from a convenience sample of 200 women prior to UD testing, and within 3 days of completion. Participants rated their level of agreement/disagreement with the following statements: I understand why I am having the test; I have been given enough information about the test; I understand what the test will involve. Women also reported their perceived levels of distress (anxiety, embarrassment, and discomfort).ResultsOne hundred fifty‐one women returned both pre‐ and post‐UD questionnaires. Most (88.9%) had read the information sheet and agreed that they understood the indications for the testing (78.1%). Fewer agreed that they understood what the tests would involve (68.2%), or that they had been given enough information about the test (64.9%). The overall distress score (anxiety, embarrassment, and discomfort) was 6 (IQR 5–7; possible range 3–9).ConclusionsUrodynamic testing remains an invasive yet prevalent form of urogynecological assessment. One‐third of our patients may not understand what UD testing involves and may not feel adequately informed about the tests. Additional research to explore informational needs is important. 30:572–577, 2011. © 2011 Wiley‐Liss, Inc.
Access link bandwidth externalities and endogenous Internet growth: a long‐run economic approach
Authors: Androutsos Athanassios 
Published: January 2011

AbstractThe evolution of end‐users' access link bandwidth over time arrives exogenously in network economics and it is typically attributed to technological advances in the area of networking. In this paper, we explore the broad issues associated with developing an economic model of access link bandwidth growth. In the proposed model bandwidth of the access link grows endogenously based on the increasing performance and quality of service requirements of the emerging Internet applications that have resulted in massive increases in demand for access capacity rates. A significant consideration of this model is that bandwidth exhibits substantial externalities or spillovers since decisions on bandwidth levels made by a single user affect all other user levels of performance. The main conclusions are that access link bandwidth externalities determine the rate of access bandwidth and Internet growth, that integration of separate networks into a universal multimedia networking technology managed by a single administration scheme and the integration of bandwidth provisioning into aggregate markets will increase the rate of growth, and that having a large user population is not sufficient to generate growth. Copyright © 2011 John Wiley & Sons, Ltd.
Mitigating unfairness in locality‐aware peer‐to‐peer networks
Authors: Lehrieder Frank , Oechsner Simon , Hoßfeld Tobias , Staehle Dirk , Despotovic Zoran , Kellerer Wolfgang , Michel Maximilian 
Published: January 2011

AbstractLocality awareness is considered as a promising approach to increase the efficiency of content distribution by peer‐to‐peer (P2P) networks, e.g., BitTorrent. It is intended to reduce the inter‐domain traffic, which is costly for Internet service providers (ISPs), and to simultaneously increase the performance from the viewpoint of P2P users, i.e., to shorten download times. This win–win situation should be achieved by a preferred exchange of information between peers which are located close to each other in the underlying network topology. A set of studies shows that these approaches can lead to a win–win situation under certain conditions, and to a win–no lose situation in most cases. However, the scenarios used mostly assume homogeneous peer distributions. This is not the case in practice according to recent measurement studies. Therefore, we extend previous work in this paper by studying scenarios with real‐life, skewed peer distributions. We show that even a win–no lose situation is difficult to achieve under those conditions and that the actual impact for a specific peer heavily depends on the used locality‐aware peer selection and the specific scenario. This contradicts the principle of economic traffic management (ETM), which aims for a solution where all involved players benefit and consequently have an incentive to adopt locality awareness. Therefore, we propose and evaluate refinements of current proposals, allowing all users of P2P networks to be sure that their application performance is not reduced. This mitigates the unfairness introduced by current proposals which is a key requirement for a broad acceptance of the concept of locality awareness in the user community of P2P networks. Copyright © 2011 John Wiley & Sons, Ltd.
Drug utilization and polypharmacy in an Italian elderly population: the EPIFARM‐elderly project
Authors: Nobili Alessandro , Franchi Carlotta , Pasina Luca , Tettamanti Mauro , Baviera Marta , Monesi Lara , Roncaglioni Carla , Riva Emma , Lucca Ugo , Bortolotti Angela , Fortino Ida , Merlino Luca 
Published: January 2011

ABSTRACTObjectiveTo investigate the prescribing patterns and the prevalence of polypharmacy in community‐dwelling elderly people, and to analyze the association of chronic medications and number of drug prescriptions with age and sex.MethodsAll prescriptions for people aged 65 years or older reimbursed by the Italian National Health Service (NHS) and dispensed by retail pharmacies of the 15 local health units (LHU) in the Lombardy Region during 2005 were analyzed. Logistic regression analysis was used to assess the association between drug prescription (overall, chronic drugs, and polypharmacy) and age, sex, and LHU of residence.ResultsEighty‐eight percent of the 1 767 239 analyzed elderly received at least one drug prescription. The overall prescription rate was slightly higher for women than men (odds ratio [OR] 1.20; 95%CI 1.19–1.21). Seventy‐six percent of the elderly received at least one chronic drug, 46% were exposed to polypharmacy, and 20% to chronic polypharmacy. At multivariate analysis, age and LHU residence of the elderly were the main determinants of drug exposure. A significant correlation was found between the overall prescription prevalence rate and exposure to chronic drugs and to chronic polypharmacy (rs = 0.79, p < 0.0005 and rs = 0.84, p < 0.0001, respectively).ConclusionsOur findings indicate that age and LHU residence of the elderly are the main determinants of drug prescribing, and there is evidence of a significant correlation between the overall prescription prevalence rate and exposure to chronic drugs and to chronic polypharmacy. Copyright © 2011 John Wiley & Sons, Ltd.
Environment‐friendly silicone sealants by self‐catalytic cross‐linking reaction of α‐aminomethyl triethoxysilanes
Authors: Yin Yigao , Zhang Yi , Chen Xiaoyan , Liu Siwei , Jiang Xing , Chi Zhenguo , Xu Jiarui 
Published: January 2011

AbstractOn the basis of the self‐catalytic characteristic of α‐aminomethyl triethoxysilanes, (diethyl) aminomethyl triethoxysilane, cyclohexylaminomethyl triethoxysilane, and anilinomethyl triethoxysilane were used as self‐catalytic cross‐linkers to prepare a series of environmental friendly, nano‐CaCO3 reinforced silicone sealants based on poly(dimethylsiloxane) (PDMS). The tensile properties, hardness, adhesive properties, hot‐air aging resistance, and oil‐resistance properties of these materials were studied by universal electronic tensile machine, scanning electron microscope, and atomic force microscopy, etc. Results show that the comprehensive properties of the self‐catalytic cross‐linking PDMS sealants are much better than that of the traditional ones. The chemical structure and reactivity of the α‐aminomethyl triethoxysilanes have a great effect on the properties of PDMS sealants. The tensile strength of the reinforced sealants with 100 phr (100 parts per hundreds of PDMS) nano‐CaCO3 is about 4.4 times than that of the unreinforced ones, and the elongation at break is about three times. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Exploring the proteome of an echinoderm nervous system: 2‐DE of the sea star radial nerve cord and the synaptosomal membranes subproteome
Authors: Franco Catarina Ferraz , Santos Romana , Coelho Ana Varela 
Published: January 2011

AbstractWe describe the first proteomic characterization of the radial nerve cord (RNC) of an echinoderm, the sea star Marthasterias glacialis. The combination of 2‐DE with MS (MALDI‐TOF/TOF) resulted in the identification of 286 proteins in the RNC. Additionally, 158 proteins were identified in the synaptosomal membranes enriched fraction after 1‐DE separation. The 2‐DE RNC reference map is available via the WORLD‐2DPAGE Portal (http://www.expasy.ch/world‐2dpage/) along with the associated protein identification data which are also available in the PRIDE database. The identified proteins constitute the first high‐throughput evidence that seems to indicate that echinoderms nervous transmission relies primarily on chemical synapses which is similar to the synaptic activity in adult mammal's spinal cord. Furthermore, several homologous proteins known to participate in the regeneration events of other organisms were also identified, and thus can be used as targets for future studies aiming to understand the poorly uncharacterized regeneration capability of echinoderms. This “echinoderm missing link” is also a contribution to unravel the mystery of deuterostomian CNS evolution.
Mechanical properties of polymer‐blend nanocomposites with organoclays: Polystyrene/ABS and high impact polystyrene/ABS
Authors: Chen Biqiong , Evans Julian R. G. 
Published: January 2011

AbstractThirty‐three polystyrene (PS)/acrylonitrile‐butadiene‐styrene (ABS) and high impact PS/ABS polymer blends with organoclay and copolymer additives were prepared by melt processing using different mixing sequences in order to test the putative capability of clay to perform a compatibilizing role in polymer blends. In general, the addition of clay increased the tensile modulus and had little effect on tensile strength. For the blends studied in this work, the addition of organoclays caused a catastrophic reduction in impact strength, a critical property for commercial viability. The polymer‐blend nanocomposites adopted a structure similar to that for ABS/clay nanocomposites as determined by X‐ray diffraction and transmission electron microscopy. It is suggested that clay reinforcement inhibits energy absorption by craze formation and shear yielding at high strain rates. Simultaneous mixing of the three components provided nanocomposites with superior elongation and energy to failure compared to sequential mixing. The clay pre‐treated with a benzyl‐containing surfactant gave the best overall properties among the various organoclays tested and of the two clay contents studied 4 wt % was preferred over 8 wt % addition. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Peak window of suicides occurs within the first month of diagnosis: implications for clinical oncology
Authors: Johnson Timothy V. , Garlow Steven J. , Brawley Otis W. , Master Viraj A. 
Published: January 2011

AbstractObjective: A diagnosis of cancer can provoke painful emotional reactions and possibly suicidal thoughts in a patient. Consequently, cancer patients carry a twofold increased lifetime risk of suicide. This risk is much higher within 1 year of diagnosis. However, it remains largely unknown whether suicide frequency remains constant within the first year. Therefore, we sought to characterize the distribution of suicides in order to potentially identify a clinically important window of peak suicide risk.Methods: We queried the Surveillance, Epidemiology, and End Results (SEER) database for cancer patients 20 + years old with diagnosed with a single malignancy from 1973 to 2005 and known cause of death, including whether a patient committed suicide. Initial frequency analysis was performed to identify the period of maximum suicide risk. One‐way ANOVA was performed to assess the relationship between year of diagnosis and suicide completions within 1 month of diagnosis.Results: The cohort consisted of 3 678 868 patients. Of the total cohort, 0.2% (5875 patients) committed suicide, 36% (2111 patients) within 1 year of diagnosis. One in three (701 of the patients) who committed suicide in the first year did so within 1 month of diagnosis. No change in this distribution occurred over time.Conclusions: Cancer patients carry an increased risk of suicide. However, this risk peaks with the month following diagnosis. Clinicians should be aware of this increased risk and include assessments of mood state and suicidality at the time of initial diagnosis of the malignancy and be prepared to provide referral to mental health treatment providers. Copyright © 2011 John Wiley & Sons, Ltd.
Efficacy of selected pesticides against synanthropic mites under laboratory assay
Authors: Stará Jitka , Stejskal Václav , Nesvorná Marta , Plachý Jan , Hubert Jan 
Published: January 2011

AbstractBACKGROUND: The efficacies of organophosphate pesticides, single‐compound versus multicompound pyrethroid formulations and relatively novel unclassified insecticides/acaricides were compared to find the lowest dosage and highest efficacy for the control of Dermatophagoides farina (Hughes), D. pteronyssinus (Trouessart) and Tyrophagus putrescentiae (Schrank). Formulated active ingredients (AIs) were diluted in water and applied onto filter paper in experimental chambers with ten unsexed adult mites in six replicates. Mite mortality was checked after 24 h. The security index (SI) was calculated for all of the AIs by dividing the recommended rate by the LD90 determined for each species.RESULTS: The tested organophosphates had high LD90 and low SI values. The single‐compound pyrethroids were ineffective (deltamethrin and beta‐cyfluthrin) or had high LD90 and low SI values (cyphenothrin, permethrin, pyrethrum and bifenthrin). The multicompound miticides had low LD90 and high SI values which increased from deltamethrin/S‐bioallethrin to permethrin/S‐bioallethrin/piperonyl butoxide to permethrin/pyriproxyfen/benzyl benzoate. Abamectin, pyridaben, propargite and flufenoxuron were highly active against Dermatophagoides spp. Neem (Acarosan duo) was highly active against all mite species tested.CONCLUSION: The available formulations of multicompound pyrethroids (permethrin/S‐bioallethrin/piperonyl butoxide, permethrin/pyriproxyfen/benzyl benzoate), benzyl benzoate, neem and some field acaricides are effective in suppression of synanthropic mites in laboratory assays. Their LD90 are lower than those of traditionally used organophosphates or single‐compound pyrethroid formulations. Copyright © 2011 Society of Chemical Industry
Auger recombination in Si1‐xGex/Si quantum wells under high‐density photoexcitation
Authors: Tayagaki Takeshi , Fukatsu Susumu , Kanemitsu Yoshihiko 
Published: January 2011

AbstractWe studied the Auger recombination in Si1‐xGex /Si quantum wells using near‐infrared photoluminescence (PL) spectroscopy. We found that the PL intensity under high‐density excitation depends strongly on the width of the single quantum wells and that the Auger recombination is more pronounced for wide wells. This indicates that the Auger recombination rate depends on the spatial profile of the hole wave function in the Si1‐xGex well layer. We discuss the method to control the nonradiative Auger recombination rate in coupled double quantum wells (CDQWs) by manipulating the wave functions; the rate is reduced by tuning the barrier width. In CDQWs voltage‐biased on the surface, the PL intensity decrease with surface voltage, but the electric field dependence of the PL intensity is complicated under low‐density‐excitation condition. This unique electric‐field dependence of the PL intensity is sensitive to the excitation intensity and the sample temperature. We tentatively attribute these PL behaviors to the appearance of the impact ionization under the low excitation intensity and high‐surface‐bias voltage conditions. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Black luminescent silicon
Authors: Pezoldt Jörg , Kups Thomas , Stubenrauch Mike , Fischer Michael 
Published: January 2011

AbstractBlack silicon is a fascinating multipurpose modification of bulk silicon which can be fabricated in a selforganized structure formation process during dry etching of bare silicon wafer leading to the formation of a high density of silicon needles. The smallest dimension of the tips approaches values between 1 and 2 nm. The silicon nanostructure exhibits an extremely low diffuse reflectivity. The nanosized tips and their coating with fluorine doped nonstoichiometric silicon dioxide are responsible for cathodoluminescence in the blue‐green and red regions of the visible spectra (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the role of heterolayer relaxation in luminescence response of Si/SiGe:Er structures
Authors: Krasilnikova Ludmila , Stepikhova Margarita , Drozdov Yurij , Chalkov Vadim , Shengurov Vladimir , Krasilnik Zakharii 
Published: January 2011

AbstractIn this contribution we discuss the luminescence properties of Si/Si1‐xGex:Er/Si structures being of interest for a laser realization. The influence of the strain relaxation processes that take place in such kind of structures on their photoluminescence response at 1.54 µm has been analyzed. The studies were performed for Si/Si1‐xGex:Er/Si structures with the different thickness of Si1‐xGex:Er layers, and consequently the degree of strain relaxation. It is shown that the structural defects arising in Si/Si1‐xGex:Er/Si structures due to the relaxation play only negligible role in their photoluminescence response. The contribution of the structural defects in the photoluminescence response at 1.54 µm became apparent only in thin partially relaxed Si/Si1‐xGex:Er/Si structures, the photoluminescence spectra of which are represented by the broad “defect related” lines. Intense photoluminescence related with the optically active Er centers of different types was observed for the strained and completely relaxed Si/Si1‐xGex:Er/Si structures containing thick (d > 1 µm) Si1‐xGex:Er layers. The external quantum efficiency of these structures reaches the value of 6.3×10‐5 at T =77 K. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrafast photoluminescence dynamics of blue‐emitting silicon nanostructures
Authors: Židek K. , Trojánek F. , Malý P. , Pelant I. , Gilliot P. , Hönerlage B. 
Published: January 2011

AbstractWe report on ultrafast photoluminescence (PL) spectroscopy of blue and red‐emitting silicon nanostructures. We prepared samples of porous Si with different dominating PL bands in time‐integrated PL spectrum. These samples show also striking differences in ultrafast PL dynamics. For the red‐emitting samples we observe rapid PL onset followed by a two‐exponential decay, which is spectrally dependent. For the blue‐emitting porous Si the PL builds up several picoseconds and decays mono‐exponentially with spectrally independent PL rise and decay times.Our results indicate that a dominant part of the blue and red emission comes from two distinct species with different energy states structures. This is furthermore supported by two‐photon absorption induced PL mea‐surements. The two‐photon and one‐photon absorption induced PL spectra, which are identical for the red‐emitting samples, differ substantially for the blue‐emitting ones. However, polarization properties of PL suggest that the blue PL band originates from several overlapping PL bands with sample‐dependent importance. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phonon‐assisted exciton spin relaxation in (In,Ga)As/GaAs quantum dots
Authors: Kurtze H. , Yakovlev D. R. , Reuter D. , Wieck A. D. , Bayer M. 
Published: January 2011

AbstractIn this work, we study the temperature‐dependent spin relaxation of exciton‐bound carriers in (In,Ga)As/GaAs quantum dots. The exciton population mapped by a time‐resolved differential transmission signal reveals a decay on two different time scales, reflecting the fractions of optically active and inactive excitons. The underlying exciton states are split from each other by the exchange interaction. The phonon‐assisted spin‐orbit interaction induces spin flips of an exciton‐bound electron or hole which convert the exciton populations into each other. The temperature‐dependent relaxation rate follows a thermal phonon distribution. Deviations indicate that two‐phonon processes involving higher orbitals may contribute significantly to the total relaxation process. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quasi‐two‐dimensional electron–hole liquid and biexcitons in SiGe layers of Si/SiGe/Si heterostructures
Authors: Shepel Denis , Burbaev Timur , Sibeldin Nikolai , Skorikov Mikhail 
Published: January 2011

AbstractThe electron–hole liquid (EHL) in quantum‐confinement SiGe layers of Si/Si1‐xGex /Si heterostructures is discovered and its properties are studied by photoluminescence spectroscopy in the near‐infrared and visible spectral ranges. It is established that the EHL is composed by quasi‐two‐dimensional holes in the quantum well formed by the SiGe layer and quasi‐three‐dimensional electrons, which occupy a wider region of space centered on this layer. Conditions on the band parameters of a type‐II heterostructure under which the formation of the EHL and biexcitons in such a structure is possible are determined. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)