bluuebunny/crossref_metadata_2025 huggingface dataset:
Humoral immune response after post‐chemotherapy booster diphtheria–tetanus–pertussis vaccine in pediatric oncology patients
Authors: Cheng Frankie Wai Tsoi , Leung Ting Fan , Chan Paul Kay Sheung , Lee Vincent , Shing Ming Kong , Chik Ki Wai , Yuen Patrick Man Pan , Li Chi Kong
Published: October 2008

Background

The role of post‐chemotherapy booster vaccination in pediatric oncology children remains to be established. In this randomized controlled study, we studied the effect of immune responses to diphtheria–tetanus–pertussis (DTP) booster vaccination in children 6 months after completing chemotherapy.

Methods

Children 1–18 years old with chemotherapy completed for 6 months (baseline) were eligible. Subjects were randomized into vaccine and control group. In the former, three doses of DTP vaccine (Aventis Pasteur Inc., Lyon, France) were administered. IgG antibody titers against diphtheria, tetanus, pertussis, hepatitis B, measles, mumps, and rubella antibodies were measured serially in vaccine and control groups. Subsets of circulating lymphocytes (CD3+, CD4+, CD8+, CD19+, and CD16/56+) were quantified by flow cytometry using fluorescence‐labeled monoclonal antibodies.

Results

Fifty‐six children (28 vaccinees; 28 controls) were enrolled. Protective antibody levels against diphtheria, tetanus, pertussis were found at baseline in 83.6%, 96.5%, 96.1% of them respectively. After three doses of DTP, all vaccinees demonstrated a sustain rise in antibody levels and the antibody titers were significantly higher than control group. 35.8% of subjects were susceptible to measles mumps and rubella infection and 69% showed anti‐HBs antibody titer less than protective level up to 18 months after stopping chemotherapy.

Conclusions

Post‐chemotherapy booster vaccinations produced a strong and sustained effect in humoral immunity against vaccine‐preventable infectious diseases. Pediatr Blood Cancer 2009;52:248–253. © 2008 Wiley‐Liss, Inc.
Flammable, thermal, and mechanical properties of intumescent flame retardant PP/LDH nanocomposites with different divalent cations
Authors: Zhang Ming , Ding Peng , Qu Baojun
Published: October 2008

The flammable, thermal, and mechanical properties of intumescent flame retardant (IFR) polypropylene/layered double hydroxide (PP/IFR/LDH) nanocomposites with the LDHs of different divalent cations and IFR system of ammonium polyphosphate/pentaerythritol (APP/PER) have been studied by X‐ray diffraction (XRD), cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), limiting oxygen index (LOI), UL‐94 test, and mechanical measurements. The XRD results show that the exfoliated PP/IFR/LDH nanocomposites possess the nanoscaled dispersion characteristic. The data from the CCT tests show the synergistic effect of LDHs with IFR can decrease considerably the HRR, MLR, and EHC values of the PP/IFR/LDH nanocomposites, in which the pk‐HRR, pk‐MLR, and pk‐EHC values of the PP/IFR/ZnAl‐LDH sample decrease to 318 kW/m2, 0.081 g/m2 s, 61.8 MJ/kg from the corresponding values 506 kW/m2, 0.115 g/m2 s, 71.8 MJ/kg of the PP/IFR sample. The LOI and UL‐94 data further support the evidence that the flame retardant synergistic effects of LDHs with IFR increase the LOI values and UL‐94 rating, especially for the LDHs with the transition ions (Zn, Cu) the LOI values can reach 33% and the UL‐94 pass the V‐0 rating. The TGA results demonstrate the LDHs can greatly improve the thermal stabilities of PP/IFR/LDH nanocomposites by increasing the thermo‐oxidation decomposition temperature and charred residues. The morphological structures observed by SEM have demonstrated the LDHs can promote formation of compact charred layers. The data from the mechanical tests show the tensile strength and elongation at break of the PP/IFR/LDH samples are basically unchanged compared with the PP/IFR sample. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Effect of polymethylmethacrylate–montmorillonite nanocomposite on the release of some biologically active 1,2,4‐triazine derivatives
Authors: Salahuddin N.A. , El‐Barbary A.A. , Abdo N.I.
Published: October 2008

Methylmethacrylate chloromethylstyrene copolymer–montmorillonite (PMMA–MMT) intercalated nanocomposite was prepared by bulk copolymerization of methylmethacrylate (MMA) and chloromethylstyrene (2 wt%) followed by phosphonium salt formation. The intercalation of polymeric phosphonium salt into montmorillonite was achieved through an ion exchange process between sodium cations in MMT and phosphonium groups attached to the copolymer. Thermogravimetric analysis (TGA) showed improved thermal stability for the intercalated nanocomposite in comparison with the pure PMMA. Biologically active compounds including 4‐amino‐6‐methyl‐3‐thioxo‐3,4‐dihydro‐2H‐[1,2,4]triazin‐ 5‐one (I), 4‐amino‐6‐methyl‐3,4‐dihydro‐2H‐[1,2,4]triazin‐3,5‐dithione (II), 4‐amino‐6‐(4‐methoxystyryl)‐3‐thioxo‐3,4‐dihydro‐2H‐[1,2,4]triazin‐5‐one (III), and 4‐amino‐6‐styryl‐3‐thioxo‐3,4‐dihydro‐2H‐[1,2,4]triazin‐5‐one (IV) have been prepared and reacted with PMMA–MMT intercalates and ion exchanged with sodium montmorillonite (MMT) in the presence of HCl. Infrared spectra (IR) show bands characteristic to amide linkage between triazine derivatives and PMMA. These nanocomposites have been characterized by X‐ray diffraction (XRD) and transmission electron microscope (TEM). The release of biologically active compounds intercalated layered silicates is controllable and these materials have a great potential as a delivery host in the pharmaceutical field. The effect of temperature and presence of saline solution on the release was studied. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Polyaniline‐supported platinum‐hydrous ruthenium oxide nanocomposite as electrocatalyst for methanol oxidation
Authors: Liu Feng‐Jiin
Published: October 2008

A novel composite electrode is fabricated through the electrodeposition of hydrous ruthenium oxide (RuO2·xH2O) and platinum (Pt) particles into the matrix of polyaniline (PANI). Scanning electron microscopy reveals that RuO2·xH2O and Pt particles are homogeneously distributed into the matrix of PANI. A comparison of the sizes of Pt and RuO2·xH2O particles incorporated into the PANI film reveals that Pt particles are smaller in sizes as compared with the sizes of RuO2·xH2O particles. The catalytic activity of composite electrodes was evaluated for the oxidation of methanol by using cyclic voltammetry and chronoamperometry. A relatively high catalytic current was noticed for the oxidation of methanol (2.37 mA/cm2) at PANI‐Pt‐RuO2·xH2O electrode (+0.6 V (V vs. Ag/AgCl) in comparison to oxidation current at PAN‐Pt (1.27 mA/cm2) electrode. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Stretching‐induced β‐crystal of iPP: Influence of stretching ratio
Authors: Shen Chang‐Yu , Zhou Ying‐Guo , Zheng Guo‐Qiang , Liu Chun‐Tai , Chen Jing‐Bo , Li Qian
Published: October 2008

The iPP sheet is extruded through a slit die, in which the extruding rate is set small enough to eliminate the shear stress as much as possible. Simultaneously, the extruded sheets were stretched with different stretching ratios (SR). With SR increasing from 1 to 6.67, fraction of β‐crystal increases dramatically from 1.5 to 13%, which indicates that SR is favorable to the occurrence of β‐crystal. However, as SR further increases, it gradually decreases to 0, which reveals that SR can steadily restrain the formation of β‐crystal. As the thickness of the sheets decreases with the increase of SR, higher cooling rate occurs for the sheets extruded at larger SR. When SR is in the range of 1–6.67, the cooling rate might probably fix the oriented chains and provide a proper thermal environment for subsequent growth of β‐crystal, thereby, fraction of β‐crystal increases. Growth of β‐crystal could be restricted by higher cooling rate, which leads to the gradual decrease of β‐crystal fraction with the further increase of SR. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Thermal conductivity of polymer nanocomposites made with carbon nanofibers
Authors: Agarwal Sushant , Khan M. Masud K. , Gupta Rakesh K.
Published: October 2008

An internal mixer was used to prepare polycarbonate (PC)‐based nanocomposites containing carbon fibers, carbon nanofibers (CNF), and mixtures of the two fillers. The influence of the filler volume fraction, the relative amounts of the two fillers, and the filler orientation relative to the direction of heat flow on the thermal conductivity was examined. Filler orientation was obtained by the extrusion of strands of the nanocomposite. The thermal conductivity was measured using a steady‐state heat conduction technique. The CNF were fragile, and their aspect ratio could be decreased during processing. In general, the composite thermal conductivity increased with increasing filler content. Fiber alignment in the heat flux direction resulted in a significant increase in thermal conductivity. Mixing of nanofibers with microfibers resulted contacts between the microfibers. This, together with fiber alignment provided large increases in the thermal conductivity. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
A multi‐stream flow technique to obtain isotropic texture in extruded thermotropic liquid crystalline polymer melts
Authors: Boles D. , Cakmak M. , Yalcin B.
Published: October 2008

In this article, we present a simple method toward achieving global orientation isotropy in a capillary‐extruded thermotropic liquid crystal polymer (TLCP), that is, a random copolyester of 73 mol% hydroxybenzoic acid (HBA) and 27 mol% hydroxynaphthoic acid (HNA), by passing it through porous, flow altering metal foam inserts placed in the pathway of extrusion. TLCP melt flow through foam metal inserts causes a rapid creation of large number of small streams of varying cross‐section that subjects all regions of the flowing body to intense shearing leading to high orientation in individual streams. These individual streams of varying velocity and direction interact to form a structure similar to a woven rope. As a direct result of this randomization effect of these small streams, the extruded liquid crystal polymer tends toward isotropic macro properties. The degree of orientation anisotropy is evidenced by scanning electron microscopy (SEM) and micro beam wide angle x‐ray diffraction (WAXD) techniques and contrasted in samples extruded with and without the presence metal foam inserts. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Science, marketing and wishful thinking in quantitative proteomics
Authors: Hackett Murray
Published: October 2008

In a recent editorial (J. Proteome Res. 2007, 6, 1633) and elsewhere questions have been raised regarding the lack of attention paid to good analytical practice with respect to the reporting of quantitative results in proteomics. Using those comments as a starting point, several issues are discussed that relate to the challenges involved in achieving adequate sampling with MS‐based methods in order to generate valid data for large‐scale studies. The discussion touches on the relationships that connect sampling depth and the power to detect protein abundance change, conflict of interest, and strategies to overcome bureaucratic obstacles that impede the use of peer‐to‐peer technologies for transfer and storage of large data files generated in such experiments.
The impact of follicular (FL) and other indolent non‐Hodgkin's lymphomas (NHL) on work productivity–a preliminary analysis
Authors: Cheung Matthew C. , Imrie Kevin R. , Friedlich Jessica , Buckstein Rena , Lathia Nina , Mittmann Nicole
Published: October 2008

Introduction: Although much is known about the efficacy, toxicity, and direct costs of treatment for follicular lymphoma (FL), there is no data assessing the impact of this diagnosis on the work productivity of affected individuals.

Methods: We conducted a cross‐sectional survey study of consecutive patients attending a malignant haematology clinic at a large multi‐disciplinary cancer centre. Patients with a diagnosis of FL or other indolent non‐Hodgkin's lymphoma completed questionnaires assessing health status, work productivity, and activity impairment.

Results: Eighty‐four patients completed the survey study (95% response). Patients who continued to work reported a minimal impact on their work productivity (10%±standard deviation SD 20; 0%=no effect and 100%=complete impairment of activity) and on their daily activities (13%±SD 25) attributable to their cancer. Prior to lymphoma diagnosis, over 71% of patients were working while 14% were retired. At the time of survey administration, only 41% of patients were still able to work with a significant proportion of patients having transitioned to retirement (36%), sick leave (10%), or unemployment (4%). On multivariate analysis, significant activity impairment (daily activity impairment>50%) was predicted by poor self‐rated health status (OR 32.1; 95% CI: 5.9–174.2; p<0.0001) and active chemotherapy treatment (OR 14.5; 95% CI: 0.91–230.9; p=0.059).

Conclusions: Although few patients with indolent lymphoma identified significant impairment in productivity, many were unable to continue employment following diagnosis, needed to miss days from work, or imposed a significant burden on caregivers. The greatest impact on activity is apparent in patients who rate their health status as poor and in those who are currently receiving systemic therapy. Copyright © 2008 John Wiley & Sons, Ltd.
Are cancer pain and depression interdependent? A systematic review
Authors: Laird Barry J.A. , Boyd Angela C. , Colvin Lesley A. , Fallon Marie T.
Published: October 2008

Objective: Pain and depression are common in cancer patients. As these are both highly prevalent, the issue of a possible interdependent association has been raised. The aim of this systematic review was to examine the available literature and explore whether there is any evidence to support a causal relationship between cancer pain and depression.

Methods: An extensive literature search was undertaken. The following databases were searched electronically: Medline (1950–2007), Embase (1988–2007), CINAHL (1982–2007) and the Cochrane Database of Systematic Reviews (Issue 2 2007). The initial literature search revealed 892 articles. Following initial screening 41 articles were independently reviewed in detail. Fourteen articles were eligible for inclusion.

Results: The mean prevalence of both depression and pain was 36.5% (range 22.1–49.0). In 9 out of 14 studies a statistically significant association was demonstrated between pain and depression. Pain intensity positively correlated with depression (P<0.05). Items such as ‘worst pain’ and ‘enjoyment of life’ (on the Brief Pain Inventory) correlated significantly with depression. When using the McGill Pain Questionnaire, depressed patients used more affective pain descriptors. It was also shown that the longer the duration of pain, the higher the risk of depression.

Conclusions: Pain and depression are highly prevalent in cancer patients; however, there have been no appropriately designed studies to examine a causal relationship. Although associations exist, the evidence available is not sufficient to support an interdependent relationship between pain and depression. A suitably designed longitudinal study to examine causality would be a relevant step in the research agenda. Copyright © 2008 John Wiley & Sons, Ltd.
The role of neuropsychological functioning in cancer survivors' return to work one year after diagnosis
Authors: Nieuwenhuijsen Karen , de Boer Angela , Spelten Evelien , Sprangers Mirjam A.G. , Verbeek Jos H. A. M.
Published: October 2008

Objective: The objective of this study was to investigate the relationship between neuropsychological functioning and the ability to work in cancer survivors.

Methods: The study involved a consecutive cohort of 45 patients who had received a primary diagnosis of cancer, were gainfully employed at baseline, and had been treated with curative intent. Twelve months after the first day of sick leave, they underwent a neuropsychological assessment that included executive function and verbal memory tests. Other clinical, person‐related, and work‐related factors were also assessed by questionnaire at this time. Ability to work was measured as perceived workability (0–10) and work status at 12 months of sick leave.

Results: Fifteen participants (33%) showed neuropsychological impairments covering various domains. The mean workability score of cancer survivors with neuropsychological impairment was 4.9, whereas those without impairments had a mean score of 6.0 (raw β = −0.19: 95% CI = −2.9 to 0.7; adjusted β = −0.15; 95% CI = −2.5 to 0.8). More cancer survivors with neuropsychological impairments (7/15, 47%) than without (9/30, 30%) had not yet returned to work (raw OR 0.5: 95% CI: 0.1–1.8; adjusted OR 0.5; 95% CI: 0.1–2.1).

Conclusions: To date, this is the largest study to assess neuropsychological functioning objectively in combination with perceived workability and work status. Impaired neuropsychological functioning was found in one‐third of the cancer survivors and was related to a lower vocational functioning, but the relationship was not statistically significant. More research is needed to test the relevance of neuropsychological impairments for vocational functioning. Copyright © 2008 John Wiley & Sons, Ltd.
Application of proteomic techniques to the study of urine and renal tissue
Authors: Vilasi Annalisa , Cutillas Pedro R. , Unwin Robert J.
Published: October 2008

The increasing application of proteomic methods to biomedical research is providing us with important new information; it holds particular promise in advancing basic and clinical renal research, but whether proteomics can ever become a routine diagnostic tool in nephrology is still uncertain. Currently, proteomic techniques are used by many groups in the search for “biomarkers” of disease, especially kidney disease, because of the ready availability of urine as an “end‐product” of renal function. However, the question as to whether any disease‐specific biomarkers exist or can be identified by proteomics is also uncertain. A growing application of proteomics in biomedical research is to understand the mechanism(s) of disease. This brief review is selective; in it we consider examples of proteomic studies of human urine for biomarkers, others that have explored renal physiology, and still others that have begun to probe the proteome of organelles. No single approach is sufficiently comprehensive, and the pooled application of proteomics to renal research will undoubtedly improve our understanding of renal function and enable us to explore in more detail subcellular structures, and to characterize cellular processes at the molecular level. When combined with other techniques in renal research, proteomics, and related analytical methods could prove indispensable in modeling renal function, and perhaps also in diagnosis and management of renal disease.
Holographic quark gluon plasma with flavor
Authors: Kaminski M.
Published: October 2008

In this work I explore theoretical and phenomenological implications of chemical potentials and charge densities inside a strongly coupled thermal plasma, using the gauge/gravity correspondence. Strong coupling effects discovered in this model theory are interpreted geometrically and may be taken as qualitative predictions for heavy ion collisions at RHIC and LHC. In particular I examine the thermodynamics, spectral functions, transport coefficients and the phase diagram of the strongly coupled plasma. For example stable mesons, which are the analogs of the QCD Rho‐mesons, are found to survive beyond the deconfinement transition. A phase transition resembling 2‐flavor QCD is discovered. The momentum diffusion rate of charmonium at strong coupling is significantly reduced compared to the weak coupling result, in reminiscence of the universal viscosity bound. This paper is based on partly unpublished work performed in the context of my PhD thesis. New results and ideas extending significantly beyond those published until now are stressed.
The HLA‐A2‐restricted PSMA peptide LLHETDSAV is poorly immunogenic in patients with metastatic prostate cancer
Authors: Knight David , Peterson Amy C. , Rini Brian I. , Harlin Helena , Gajewski Thomas F. , Stadler Walter M.
Published: October 2008

Background

Increasing evidence suggests that prostate cancer is visible to the immune system and is potentially responsive to immunotherapeutic interventions. Previous work has identified prostate‐specific membrane antigen (PSMA) as a potential antigen for T‐cell recognition, and specific PSMA epitopes presented by HLA‐A2 have been described. One vaccination strategy that is being pursued in the clinic utilizes peptide‐pulsed peripheral blood mononuclear cells (PBMC) + IL‐12.

Methods

HLA‐A2+ patients with castrate‐resistant prostate cancer and normal organ function were considered. Vaccines were prepared using autologous PBMC loaded with a PSMA peptide previously reported to be immunogenic (LLHETDSAV) administered subcutaneously every 3 weeks. T‐cell responses and tumor activity were assessed.

Results

Although the vaccine was well tolerated, no clinical responses were observed in 12 enrolled patients and no immune responses were detected based on an ex vivo IFN‐γ ELISPOT assay. To examine immunogenicity of this PSMA peptide in more detail, an in vitro priming assay was utilized with normal donor PBMC, and no detectable reactivity was observed.

Conclusions

Our results suggest that the PSMA peptide LLHETDSAV is poorly immunogenic in humans and that alternative prostate cancer antigens should be pursued. Prostate 69: 142–148, 2009. © 2008 Wiley–Liss, Inc.
Sublethal effects of four insecticides on the reproduction and wing formation of brown planthopper, Nilaparvata lugens
Authors: Bao Haibo , Liu Shuhua , Gu Jianhua , Wang Xizhen , Liang Xiaolong , Liu Zewen
Published: October 2008

BACKGROUND: The brown planthopper (BPH), Nilaparvata lugens Stål, is a major rice pest in many parts of Asia. Neonicotinoids such as imidacloprid and dinotefuran are widely used for control of this pest, and resistance to these insecticides has developed in recent years. This pest has also been widely exposed to triazophos and fenvalerate, although these insecticides are not used for the control of the pest directly. Here, the effects of sublethal doses of these four insecticides on the reproduction and wing formation in BPH were examined.

RESULTS: Imidacloprid and dinotefuran reduced the fecundity of BPH to 68.8% and 52.4% in macropterous families, and to 57.9% and 43.1% in brachypterous families, when compared with the untreated controls. By contrast, triazophos and fenvalerate increased fecundity. In both macropterous and brachypterous families, sublethal doses of imidacloprid and dinotefuran showed significant induction of macropterous adults.

CONCLUSION: Imidacloprid and dinotefuran could reduce the fecundity of BPH to a significant extent, demonstrating further activity against this pest in addition to their direct toxicity. The significant induction of macropterous adults by sublethal doses of imidacloprid and dinotefuran is of importance in the management of this pest, particularly in the areas of predicting the size of emigrating populations and the numbers of insects likely to occur in newly colonized areas. Copyright © 2008 Society of Chemical Industry
Local optimization strategy based on first principles of thermoelectrics
Authors: Seifert W. , Müller E. , Walczak S.
Published: October 2008

A central target of theoretical studies on thermoelectric (TE) functionally graded materials (FGM) is to elaborate recipes for optimum design of TE elements, i.e. to identify optimum spatial profiles of the functional material parameters Seebeck coefficientS, electrical conductivityσ, and thermal conductivityκfor TE elements operating in a temperature difference. For long, clear guidelines for optimum spatial profiles have not been available yet. Meanwhile, parameter studies on graded TE elements have shown that gradual performance improvement is feasible for preferable combinations of parameter profiles. These studies have been based on an unified 1D model for both TE generator (TEG) and Peltier cooler (TEC) single elements.

This paper presents a new, analytically based optimization strategy by taking into consideration that both concentration and temperature profiles are governed by a differential equation which can be derived from first principles of the phenomenological theory of thermoelectricity. Furthermore, the compatibility approach introduced by Snyder and Ursell is taken into account. This concept enables the description of both TEG and TEC in terms of the relative current densityuas a new, intensive state variable of a TE system.

The consequences of these basic assumptions will be discussed theoretically, leading to a one‐parameter optimization strategy and to different optimum material gradients for performance parameters of practical interest like COP for a Peltier device and efficiency or electrical power output for a TE generator. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of hydrophilic and photocatalytically active TiO2 thin films by plasma based ion implantation and deposition
Authors: Manova Darina , Gjevori Altin , Haberkorn Frank , Lutz Johanna , Dimitrov Slavcho , Gerlach Jürgen W. , Valcheva Evgenia , Mändl Stephan
Published: October 2008

Titanium dioxide thin films were deposited near room temperature by plasma based ion implantation and deposition with the voltage pulses, accelerating the ions towards the substrate, ranging from 0 kV to 10 kV. Correspondingly, an increase of average energy per deposited particle from 2.5 eV to 450 eV was obtained. Even for the highest energy, a mixture of anatase and rutile is present. The increase in deposited energy was closely correlated with an increased sensitivity towards UV‐A radiation with the surface energy increasing from 25 up to 100 mN/m after illumination at 1 mW/cm2, corresponding to a hydrophilic and photocatalytically active phase. Additional influences of the substrate type – Si(100), fused silica and thermal oxide on silicon – were found, despite a layer thickness of about 300 nm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparative study of La0.67Ca0.33MnO3 composites with different secondary phases
Authors: Ren Guang Ming , Yuan Song Liu
Published: October 2008

Two kinds of composites with the nominal composition of (1 – x)La0.67Ca0.33MnO3 (LCMO)/x MgO and (1 – x)LCMO/ x SrO were investigated. Different electrical and magnetic transport properties were observed between the two kinds of composites. For the LCMO/MgO composites, the insulator–metal transition temperature (Tp) decreases rapidly with the increase of MgO content and a remarkably enhanced magnetoresistance (MR) peak is observed near Tp. However, for the LCMO/SrO composites, the SrO content has little effect on Tp and the low‐field MR is enhanced over almost the whole temperature range. Moreover, a two‐step magnetization behavior was observed in the LCMO/MgO composites. By calculating in terms of a ferromagnetic grain coupling model, we attribute this difference to the different effects of the secondary phases on the ferromagnetic coupling between the neighboring LCMO grains, which results from the formation of the different interfacial phases at the grain boundary in the two kinds of composites. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gliding dislocations in Bi2Te3 materials
Authors: Peranio N. , Eibl O.
Published: October 2008

In Bi2Te3, dislocations were found with an uniquely high mobility at room temperature. The gliding dislocations were analysed and their effect on the thermoelectric properties is discussed. The glide of dislocations was induced by heating with a focused electron beam at 120 keV, external stresses were not applied. The dislocations were bowed out in the glide direction and were only pinned at the surface of the samples. Stereomicroscopy combined with image simulations yielded basal plane dislocations with a density of 109 cm–2 and Burgers vectors of type 〈110〉. Video sequences showing the glide of single dislocations and groups of dislocations were recorded. Isolated dislocations showed a high mobility in ±〈110〉 direction at a velocity of 10–100 nm s–1. Dislocation dipoles were pinned and did not glide. Dislocations equidistantly arranged within the same glide plane showed a collective movement. Dislocations piled up in different glide planes were fixed and acted as barriers for gliding dislocations. The motion of dislocations was attributed to residual shear stresses of about 10 MPa, and their glide directions depended on the sign of the Burgers vector. Attractive and repulsive forces of dislocations directly visualise the forces due to the elastic strain fields of other dislocations. The relevance of phonon scattering on dislocations in Bi2Te3, particularly due to their high mobility and density, was confirmed by two inspections: (i) Dislocations decrease the lattice thermal conductivity due to phonon scattering on the elastic strain field. The phonon mean free path was estimated to about 800 µm at 3 K and agreed with published data. (ii) The dislocation resonance theory of Granato and Lücke predicts an interaction between phonons and dislocations acting as oscillating strings. The attenuation of ultrasound was estimated and was compared with published data. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin‐density‐wave gap in (TMTSF)2PF6 probed by reflection‐type terahertz time‐domain spectroscopy
Authors: Watanabe Shinichi , Kondo Ryusuke , Kagoshima Seiichi , Shimano Ryo
Published: October 2008

We report on a development of the reflection‐type terahertz time‐domain spectroscopy system and apply it to determine the conductivity spectra of the spin density wave (SDW) ground states in (TMTSF)2PF6. We take special care over optimizing the spatial resolution of the measurement system in order to investigate the tiny sample and also for correcting the phase error of the measurement. We observe a distinct reduction of the optical conductivity below ∼65 cm–1, which is a clear indication of SDW gap formation with metal–insulator transition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cooling and spin‐relaxation dynamics of spin‐polarized excitons in a diluted magnetic semiconductor quantum well
Authors: Murayama A. , Saito K. , Souma I.
Published: October 2008

We show a systematic study on cooling and spin‐relaxation dynamics of spin‐polarized excitons in a diluted magnetic semiconductor quantum well of Cd0.95Mn0.05Te, by means of pump‐probe absorption spectroscopy under magnetic fields. Time dependences of circularly polarized saturation absorption intensities after optical pumping showed the dynamics of carrier cooling and spin relaxation at spin‐split exciton sublevels at various magnetic fields. Spin‐polarized electrons at a higher‐energy up‐spin state relax to a lower‐energy down‐spin one with time constants ranging from 6 to 20 ps, depending on the magnetic field. Roles of phonon scattering and emission in the electron‐spin relaxation are pointed out, in addition to a spin‐flip process induced by local Mn spins via s‐d exchange interaction. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strong exciton‐photon coupling and its polarization dependence in a metal‐mirror microcavity with oriented PIC J‐aggregates
Authors: Oda Masaru , Hirata Kazuyuki , Inoue Tokiko , Obara Yuki , Fujimura Tomoko , Tani Toshiro
Published: October 2008

We present a study of strong exciton‐photon coupling and its dependence on incident light polarization in a metal‐metal mirror microcavity containing PIC J‐aggregates. Rabi‐splitting energies between upper and lower polariton branches are estimated as 94 meV and 69 meV for s‐ and p‐polarized incident light, respectively. These large values are due to large oscillator strength of Frenkel excitons in the PIC J‐aggregates and strong confinement of light attributed to the metallic microcavity as well. As for the effective thickness of the active layer for s‐polarized light, a good agreement is obtained between Lfiteff = 201 nm deduced from the experimental data and Lcalceff = 207 nm calculated from the summation of the measured thickness of active layer with the estimated penetration depths into silver mirrors. We also discuss the difference in the polarization dependences of Rabi‐splitting energy, quantitatively. It is concluded that the polarization dependence is mainly due to an alignment of the J‐aggregates in the active layer and is not affected so much by anisotropy of the penetration depths into the silver mirrors. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The optical spectra of confined polygermanes: from bulk film down to nanosize layers
Authors: Ostapenko Nina , Kozlova Nata , Nanjo Masato , Mochida Kunio , Suto Shozo
Published: October 2008

The monitoring of poly(di‐n‐hexylgermane) (PDHG) optical spectra in a variety of structures ranging from a polymer film to nanosize polymer filled porous media was performed by optical spectroscopy in the temperature range from 5 to 250 K. The PDHG nanocomposites were fabricated by insertion of PDHG polymers into SBA‐15 mesoporous silica and SiO2 porous films. Temperature dependence of the PDHG film fluorescence spectra shows that the polymer generally has disordered conformation while the random ordered segments behave as defects. The spectra of the composites correspond to the polymer chains with even less ordered segments and the aggregates of such chains. This is confirmed by the absence of the thermochromic transition in the composites contrary to the film. The difference between the optical spectra of the film and the composites is due to a decrease of both the intermolecular and exciton‐phonon interactions in the composites. It was shown that the polymer chains in the SiO2 pores are more ordered. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitons in perylene tetracarboxdiimide crystals for optoelectronics
Authors: Provencher Françoise , Laprade Jean‐Frédéric , Côté Michel , Silva Carlos
Published: October 2008

In this contribution, we present steady‐state and timeresolved photoluminescence measurements, as well as absorbance measurements, on dilute solutions and on solution‐grown crystals of a perylene tetracarboxdiimide derivative (EPPTC). We also present density functional theory (DFT) calculations of their electronic structure. These molecules self‐assemble into highly anisotropic needle‐shaped crystals with monoclinic structure, as revealed by X‐ray diffraction techniques and polarized optical microscopy.

We find experimentally that the Huang‐Rhys factor for this molecule is 0.565, which is in good agreement with that extracted from ab initio calculations (0.678). We demonstrate that in a film, the nature of photoexcitations is a vibrationally dressed Frenkel exciton and that these recombine radiatively with a distribution of excited‐state constants centered at ∼ 1 ns–1. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time‐resolved absorption and luminescence following electron‐hole pair creation in ZnO
Authors: Wall R. Andrew , Lipke Kyle C. , Ucer K. B. , Williams R. T. , Millers D. , Smits K. , Grigorjeva L.
Published: October 2008

We report transient absorption induced by electron‐hole excitation in undoped ZnO. A laser pump/continuum probe method covers 2–300 ps, and an electron pulse with lamp transmission covers 8–300 ns. The broad absorption spectrum increases monotonically with wavelength from 900 to 1600 nm. Following a reasonable hypothesis that the free‐carrier‐like induced infrared absorption is proportional to the total number of free carriers, excitons, and shallow‐trapped carriers in the sample, these data allow setting an upper limit on the quantum efficiency of a specified lifetime component of luminescence. For the undoped commercial ZnO studied in this report, the quantum efficiency of room temperature excitonic luminescence is less than 5%. This means that there is significant room for improvement in applications aiming to use room‐temperature excitonic blue luminescence of ZnO for fast scintillators and light sources. Direct observation that a large majority of excitations are tied up for more than 100 nanoseconds in shallow traps confirms the premise for studies undertaken at Oak Ridge National Laboratory to improve the excitonic luminescence yield and decay rate of ZnO by donor doping. The preliminary results presented here on undoped ZnO suggest that induced absorption measurements should be a useful diagnostic of quantum efficiency while studying such dopant effects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multichanneled relaxation of halogen‐bridged diplatinum chain complexes photoexcited
Authors: Yamamoto Shoji , Ohara Jun
Published: October 2008

Employing a time‐dependent Hartree‐Fock method, we simulate photoexcitation and the following nonlinear lattice relaxation of quasi‐one‐dimensional binuclear platinum complexes with bridging halogens. High‐energy excitations above the electron‐hole continuum tend to relax into polarons, while excitons pumped within the optical gap can be stabilized into solitons.

Both neutral and charged solitons appear as stable photoproducts, which is not the case with conventional platinum‐halide chains. When a pair of kink and antikink is born out of a self‐trapped exciton and recombine to disappear, excess spin and charge densities alternate and oscillate on them. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical spin injection into InGaAs quantum dots: single dot devices and time‐resolved studies
Authors: Hetterich M. , Löffler W. , Aßhoff P. , Flügge H. , Müller J. , Westenfelder B. , Hu D. Z. , Schaadt D. M. , Kalt H.
Published: October 2008

In the context of a potential future quantum information processing we investigate the concurrent initialization of electronic spin states in InGaAs quantum dots (QDs) via electrical injection from ZnMn(S)Se spin aligners. Single dots can be read out optically through metallic apertures on top of our spin‐injection light‐emitting diodes (spin‐LEDs). A reproducible spin polarization degree close to 100% is observed for a subset of the QD ensemble. However, the average polarization degree is lower and drops with increasing QD emission wavelength. Our measurements suggest that spin relaxation processes outside the QDs, related to the energetic position of the electron quasi‐Fermi level, as well as defect‐related spin scattering at the III–V/II–VI interface should be responsible for this effect, leading us to an improved device design. Finally, we present first time‐resolved electroluminescence measurements of the polarization dynamics using nanosecond‐pulsed electrical excitation. The latter should enable us to gain a more detailed understanding of the spin relaxation processes in our devices. They are also the first step towards future time‐resolved spin manipulation experiments. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of homogeneous and inhomogeneous broadenings of quantum‐well excitons by 2DFTS: An experiment‐theory comparison
Authors: Kuznetsova Irina , Thomas Peter , Meier Torsten , Zhang Tianhao , Cundiff Steven T.
Published: October 2008

The recently developed two‐dimensional Fourier‐Transform‐Spectroscopy (2DFTS) in the optical regime has been established as an elegant experiment, which has manifold of applications in the investigation of semiconductor nanostructures. Here we focus on the real and imaginary part 2DFT spectra. As predicted recently, using rephasing and non‐rephasing modes, we are able to determine the homogeneous and inhomogeneous broadenings of coupled excitonic resonances even for weak disorder where photon‐echo data are not useful. Computed real and imaginary parts of the 2DFTS for rephasing and non‐rephasing modes are compared with experimental data of a GaAs quantum well. It is demonstrated, that phase sensitive data for the rephasing and non‐rephasing modes are able to accurately provide the disorder induced broadening in a complex coupled system for each transition separately. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lasing in single ZnO nanorods after fs‐ and ns‐pulsed excitation
Authors: Fallert J. , Dietz R. J. B. , Zhou H. , Sartor J. , Klingshirn C. , Kalt H.
Published: October 2008

In this work we examine the lasing properties of single ZnO nanorods under ns‐ and fs‐pulsed excitation. By measuring the photoluminescence of individual nanorods excited by a single ns‐pulse we demonstrate that several stable lasing modes are emitted by the nanorod. In this quasi‐stationary excitation regime lasing up to room temperature can be achieved. Measurements of the temperature dependent laser threshold and of the spectral lasing region are presented. The excitation with fs‐pulsed excitation combined with a time resolved photoluminescence measurement gives furthermore an insight in the lasing dynamics. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microscopic analysis of high‐harmonic generation in semiconductor nanostructures
Authors: Golde Daniel , Meier Torsten , Koch Stephan W.
Published: October 2008

A microscopic analysis of the emitted radiation of a semiconductor nanostructure after excitation with an extremely intense ultrashort laser pulse is presented. It is shown that the extreme nonlinear optical response is not sufficiently described by pure interband transitions but one has to include intraband effects as well.

Numerical solutions of extended Bloch equations that include the coupled inter‐ and intraband dynamics are presented. For large excitation intensities, the intraband effects strongly modify the polarization dynamics and lead to a strong enhancement of high‐harmonic generation compared to pure interband dynamics. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of traveling phonon wave packets on the optical response of quantum dots
Authors: Huneke J. , Kuhn T. , Axt V. M. , Machnikowski P.
Published: October 2008

The influence of phonon wave packets created by the optical excitation of a quantum dot (QD) structure on four‐wave‐mixing (FWM) signals is analyzed theoretically. Two different structures are compared: a single QD in a half‐space geometry located close to the surface, where the emitted phonon wave packet after reflection at the surface reenters the QD and a pair of QDs in an infinite medium, where the phonon wave packet created in one QD travels across the other QD. Although the strain fields are very similar pronounced differences in the FWM polarizations are found.

In the single QD system we observe clear signatures of the reflected wave packet in the FWM signal at positive delay times, which can also be observed in the time‐integrated FWM signal from an inhomogeneously broadened ensemble of such QDs. In the two QD case no signatures of the traveling wave packet are seen in the signal at positive delays and, consequently, in the ensemble signal. However, they are clearly seen in the FWM signal at negative delay times. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rapid classification of enzymes in cleaning products by hydrolysis, mass spectrometry and linear discriminant analysis
Authors: Beneito‐Cambra Miriam , Herrero‐Martínez José Manuel , Simó‐Alfonso Ernesto F. , Ramis‐Ramos Guillermo
Published: October 2008

A method for the rapid classification of proteases, lipases, amylases and cellulases used as enhancers in cleaning products, based on precipitation with acetone, hydrolysis with HCl, dilution of the hydrolysates with ethanol, and direct infusion into the electrospray ion source of an ion‐trap mass spectrometer, has been developed. The abundances of the ([M+H]+ ions of the amino acids, from the hydrolysates of both the enzyme industrial concentrates and the detergent bases spiked with them, were used to construct linear discriminant analysis models, capable of distinguishing between the enzyme classes. For this purpose, the variables were normalized as follows: (A) the ion abundance of each amino acid was divided by the sum of the ion abundances of all the amino acids in the corresponding mass spectrum; (B) the ratios of pairs of ion abundances were obtained by dividing the ion abundance of each amino acid by each one of the ion abundances of the other 17 amino acids in the corresponding mass spectrum. Using normalization procedure B, excellent class‐resolution between proteases, lipases, amylases and cellulases was achieved. In all cases, enzymes in industrial concentrates and manufactured cleaning products were correctly classified with >98% assignment probability. Copyright © 2008 John Wiley & Sons, Ltd.
Perfume fingerprinting by easy ambient sonic‐spray ionization mass spectrometry: nearly instantaneous typification and counterfeit detection
Authors: Haddad Renato , Catharino Rodrigo Ramos , Marques Lygia Azevedo , Eberlin Marcos Nogueira
Published: October 2008

Perfume counterfeiting is an illegal worldwide practice that involves huge economic losses and potential consumer risk. EASI is a simple, easily performed and rapidly implemented desorption/ionization technique for ambient mass spectrometry (MS). Herein we demonstrate that EASI‐MS allows nearly instantaneous perfume typification and counterfeit detection. Samples are simply sprayed onto a glass rod or paper surface and, after a few seconds of ambient drying, a profile of the most polar components of the perfume is acquired. These components provide unique and reproducible chemical signatures for authentic perfume samples. Counterfeiting is readily recognized since the exact set and relative proportions of the more polar chemicals, sometimes at low concentrations, are unknown or hard to reproduce by the counterfeiters and hence very distinct and variable EASI‐MS profiles are observed for the counterfeit samples. Copyright © 2008 John Wiley & Sons, Ltd.
A perception‐driven autonomous urban vehicle
Authors: Leonard John , How Jonathan , Teller Seth , Berger Mitch , Campbell Stefan , Fiore Gaston , Fletcher Luke , Frazzoli Emilio , Huang Albert , Karaman Sertac , Koch Olivier , Kuwata Yoshiaki , Moore David , Olson Edwin , Peters Steve , Teo Justin , Truax Robert , Walter Matthew , Barrett David , Epstein Alexander , Maheloni Keoni , Moyer Katy , Jones Troy , Buckley Ryan , Antone Matthew , Galejs Robert , Krishnamurthy Siddhartha , Williams Jonathan
Published: October 2008

This paper describes the architecture and implementation of an autonomous passenger vehicle designed to navigate using locally perceived information in preference to potentially inaccurate or incomplete map data. The vehicle architecture was designed to handle the original DARPA Urban Challenge requirements of perceiving and navigating a road network with segments defined by sparse waypoints. The vehicle implementation includes many heterogeneous sensors with significant communications and computation bandwidth to capture and process high‐resolution, high‐rate sensor data. The output of the comprehensive environmental sensing subsystem is fed into a kinodynamic motion planning algorithm to generate all vehicle motion. The requirements of driving in lanes, three‐point turns, parking, and maneuvering through obstacle fields are all generated with a unified planner. A key aspect of the planner is its use of closed‐loop simulation in a rapidly exploring randomized trees algorithm, which can randomly explore the space while efficiently generating smooth trajectories in a dynamic and uncertain environment. The overall system was realized through the creation of a powerful new suite of software tools for message passing, logging, and visualization. These innovations provide a strong platform for future research in autonomous driving in global positioning system–denied and highly dynamic environments with poor a priori information. © 2008 Wiley Periodicals, Inc.