bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonequilibrium carrier dynamics in self‐assembled InGaAs quantum dots
Authors: Wesseli M. , Ruppert C. , Trumm S. , Krenner H. J. , Finley J. J. , Betz M. 
Published: August 2006

AbstractCarrier dynamics in InGaAs/GaAs quantum dots is analyzed with highly sensitive femtosecond transmission spectroscopy. In a first step, measurements on a large ensemble of nanoislands reveal the dynamical electronic filling of quantum dots from the surrounding wetting layer. Most interestingly, we find a spin‐preserving phonon mediated scattering into fully localized states within a few picoseconds. Then, individual artificial atoms are isolated with metallic shadow masks. For the first time, a single self‐assembled quantum dot is addressed in an ultrafast transmission experiment. We find bleaching signals in the order of 10−5 that arise from individual interband transitions of one quantum dot. As a result, we have developed an ultrafast optical tool for both manipulation and read‐out of a single self‐assembled quantum dot. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherent nonlinear optical response of excitons and biexcitons in quantum dots coupled to phonons
Authors: Krügel A. , Axt V. M. , Kuhn T. , Vagov A. , Peeters F. M. 
Published: August 2006

AbstractFour wave mixing signals from single dots and dot ensembles involving excitonic and biexcitonic transitions are discussed. The results have been obtained analytically from a four level dot model coupled to longitudinal acoustic phonons. Time integrated four wave mixing amplitudes for quantum dot ensembles exhibit polarization dependent quantum beats that have already been found in experimental data. In four wave mixing signals of single quantum dots we find that the ground state to exciton transition has two contributions. One is identical to the known solution of the two level quantum dot model and leads to symmetric spectra for longer delay times, while the other comprises phase information from the biexciton and results in asymmetric spectra. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport through coupled quantum dots
Authors: Brandes Tobias 
Published: August 2006

AbstractA brief survey of theoretical activities on electronic transport in coupled charge qubits is given. Some subtleties of the double quantum dot model (infinite bias, infinitely strong Coulomb blockade) are pointed out, and the motivation behind using ac‐field, noise and entanglement as a probe for testing transport in a simple setting is discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theory of excitation transfer in coupled nanostructures – from quantum dots to light harvesting complexes
Authors: Richter Marten , Ahn Kwang Jun , Knorr Andreas , Schliwa Andrei , Bimberg Dieter , Madjet Mohamed El‐Amine , Renger Thomas 
Published: August 2006

AbstractSpatially localized but electromagnetically coupled electrons are model systems for excitation transfer on nanoscales. A unified description of coupled semiconductor quantum dots and coupled cholorophylls in light harvesting complexes is presented, considering Coulomb interaction including excitonic Förster‐coupling and (bi‐) excitonic shifts as well as electron–phonon interaction. Linear absorption spectra are calculated and principles for the description of third order optical nonlinearities are outlined. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitation mechanisms of coherent phonons unravelled by femtosecond X‐ray diffraction
Authors: Bargheer M. , Zhavoronkov N. , Woo J. C. , Kim D. S. , Woerner M. , Elsaesser T. 
Published: August 2006

AbstractCoherent zone‐folded longitudinal acoustic phonons (ZFLAPs) were measured nondestructively with sub‐picometer spatial and sub‐picosecond time resolution via ultrafast X‐ray diffraction (XRD). The femtosecond excitation of a GaAs/AlGaAs superlattice with 1.5 eV photons results in spatially periodic stress, which induces a coherent ZFLAP with a 3.5 ps period. The motion is directly monitored by femtosecond X‐ray pulses at a kilohertz repetition rate. The intensity change ΔR /R = 0.03 of the −1st order satellite peak of the (002) reflection of bulk AlGaAs is directly proportional to the induced lattice strain of Δa /a 0 = 1.5 × 10−4. The phase and amplitude of the oscillatory XRD signal around a new equilibrium demonstrates the displacive excitation of coherent phonons (DECP) as the dominant mechanism for strong excitation. We discuss different mechanisms which account for impulsive stress, and argue that the electronic stress due to the deformation potential dominates. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrafast THz spectroscopy of correlated electrons: from excitons to Cooper pairs
Authors: Kaindl R. A. , Huber R. , Schmid B. A. , Carnahan M. A. , Hägele D. , Chemla D. S. 
Published: August 2006

AbstractInsulating, conducting, and superconducting phases can be identified through their characteristic low‐energy response. We discuss experiments that employ ultrashort coherent THz pulses and direct field‐resolved detection to probe time‐varying correlations of charge carriers in semiconductors and superconductors. These experiments detect 1s–2p intra‐exciton resonances of photoexcited e–h gases in GaAs quantum wells. Stimulated emission from intra‐excitonic transitions is observed in Cu2O, between 3p and 2s exciton states. Finally, we discuss the formation kinetics of Cooper pairs from nonequilibrium quasiparticles as observed in the transient THz response of the high‐T C superconductor Bi‐2212. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In vitro Immunomodulatory activities of a newly concocted traditional Chinese medicine formula: VI‐28
Authors: Lee S. K. W. , Wong C. K. , Poon P. M. K. , Ip P. S. P. , Che C. T. , Fung K. P. , Leung P. C. , Lam C. W. K. 
Published: August 2006

AbstractPrevious studies have suggested that Vigconic VI‐28, an anti‐aging traditional Chinese medicine (TCM) formula containing Radix Ginseng and Cornu Cervi Pantotrichum, possesses immunological efficacy. This in vitro study further investigated the immunomodulatory effects of the hot water extracts of VI‐28. The study included (1) colorimetric 5‐bromo‐2′‐deoxy‐uridine proliferation ELISA for estimating mitogenicity in human peripheral blood mononuclear cells (PBMC), (2) immunofluorescence staining for measuring the expression of IL‐2 receptor α (CD25) on lymphocytes, (3) cytometric bead array (CBA) for quantifying cytokine liberation from PBMC, and (4) intracellular immunophenotyping for macrophage phagocytosis and hydrogen peroxide (H2O2) production from monocytes. The results demonstrated that VI‐28 (1) could dose‐dependently inhibited the proliferation of unstimulated and lipopolysaccharide‐activated PBMC but enhanced the proliferation of phytohemagglutinin‐activated PBMC at concentrations of <1 mg/mL, (2) significantly augmented the expression of CD25 on lymphocytes at concentrations of 0.4 mg/mL or above (p < 0.05), (3) dose dependently (0.1–1.0 mg/mL) activated macrophage phagocytosis and monocyte synthesis of H2O2 and (4) significantly increased the production of cytokines IL‐8, IL‐10, IL‐12 and IL‐1β at various concentrations of VI‐28 (p < 0.05). The results suggest that VI‐28 is a potential immunomodulator which probably acts through the activation of lymphocytes and monocytes. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of nitric oxide scavenging activity, In Vitro and Ex Vivo, of selected medicinal plants traditionally used in inflammatory diseases
Authors: Basu Subhalakshmi , Hazra Banasri 
Published: August 2006

AbstractSteroidal and non‐steroidal antiinflammatory drugs, despite their various side effects, are in great demand worldwide. Alternatively, herbal formulations provide relief to a large percentage of the population suffering from inflammatory diseases. Therefore, such practices need to be rationalized through a mechanistic approach. Thus, four traditional medicinal plants, namely Ventilago madraspatana Gaertn., Rubia cordifolia Linn., Lantana camara Linn. and Morinda citrifolia Linn. were selected for a study on the inhibition of nitric oxide (NO•), a key mediator in the phenomenon of inflammation, signifying the presence of effective antiinflammatory constituents therein. Plant samples were extracted with different solvents for evaluation of their inhibitory activity on NO• produced in vitro from sodium nitroprusside, and in LPS‐activated murine peritoneal macrophages, ex vivo. Further, the inhibition of NO• synthesis was correlated with the reduction of iNOS protein expression through Western blot. Notable NO• scavenging activity was exhibited in vitro by some extracts of V. madraspatana, R. cordifolia and L. camara (IC50 < 0.2 mg/mL). Most of them showed marked inhibition (60%–80%), ex vivo, at a dose of 80 µg/mL without appreciable cytotoxic effect on the cultured macrophages. Immunoblot analysis confirmed that the modulatory effect of the samples had occurred through suppression of iNOS protein. Copyright © 2006 John Wiley & Sons, Ltd.
F‐κB modulators from Valeriana officinalis
Authors: Jacobo‐Herrera Nadia J. , Vartiainen Nina , Bremner Paul , Gibbons Simon , Koistinaho Jari , Heinrich Michael 
Published: August 2006

AbstractValeriana officinalis (Valerianaceae) has been of great interest for its therapeutic uses for treating mild nervous tension and temporary sleeping problems. In traditional European medicine it has been also reported as an antiinflammatory remedy. This study reports that the EtOAc extract of the underground parts of V. officinalis showed inhibitory activity against NF‐κB at 100 µg/mL in the IL‐6/Luc assay on HeLa cells and provided protection against excitotoxicity in primary brain cell cultures at micromolar concentrations. Bioassay‐guided fractionation of the EtOAc extract led to the isolation of three known sesquiterpenes: acetylvalerenolic acid (1), valerenal (2) and valerenic acid (3), 1 and 3 were active as inhibitors of NF‐κB at a concentration of 100 µg/mL. Acetylvalerenolic acid (1) reduced NF‐κB activity to 4%, whereas valerenic acid (3) reduced NF‐κB activity to 25%. Copyright © 2006 John Wiley & Sons, Ltd.
Neuropharmacological evaluation of Ginkgo biloba phytosomes in rodents
Authors: Naik Suresh R. , Pilgaonkar Vinaya W. , Panda Vandana S. 
Published: August 2006

AbstractOn oral administration, Ginkgo biloba phytosomes significantly reduced pentobarbitone‐induced sleeping time, produced an alteration in the general behaviour pattern, increased spontaneous motility and inhibited the chlorpromazine‐induced blockade of conditioned and unconditioned responses in rodents. They exhibited both antiamnestic and antidepressant activities in the scopolamine‐induced amnesia test and behavioural despair test, respectively. However, the phytosomes failed to show anticonvulsant activity. The observations suggest that the G. biloba phytosomes possess moderate antiamnestic/nootropic activity. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of antioxidant activity of Ginkgo biloba phytosomes in rat brain
Authors: Naik Suresh R. , Pilgaonkar Vinaya W. , Panda Vandana S. 
Published: August 2006

AbstractGinkgo biloba from the traditional Chinese system of medicine has been found to possess neurocognitive enhancing effects. The mechanism of action of Ginkgo seems to be related to its antioxidant properties. In the present study, Ginkgo biloba phytosomes were administered to Wistar rats at 50 mg/kg and 100 mg/kg for 7 and 14 days. Chemical hypoxia was induced by administration of sodium nitrite (75 mg/kg) 1 h after the last administration of treatment. Thirty minutes after sodium nitrite administration, the animals were killed and the cerebral cortex, cerebellum, hippocampus and striatum were isolated and homogenized. The supernatants were used for the estimation of the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. Ginkgo biloba phytosome treatment was found to increase superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities in all the brain regions compared with those treated only with sodium nitrite. The prevention of depletion of the antioxidant enzymes by sodium nitrite in the presence of Ginkgo biloba phytosomes may be correlated to its antioxidant activity. Copyright © 2006 John Wiley & Sons, Ltd.
Antioxidative effects of pumpkin seed (Cucurbita pepo) protein isolate in CCl4‐Induced liver injury in low‐protein fed rats
Authors: Nkosi C. Z. , Opoku A. R. , Terblanche S. E. 
Published: August 2006

AbstractThe effects of pumpkin seed (Cucurbita pepo) protein isolate on the plasma activity levels of catalase (CA), superoxide dismutase (SOD), glutathione peroxidase (GSHpx) and total antioxidant capacity (TAC) as well as glucose‐6‐phosphatase (G6Pase) in liver homogenates and lipid peroxidation (LPO‐malondialdehyde‐MDA) levels in liver homogenates and liver microsomal fractions against carbon tetrachloride (CCl4)‐induced acute liver injury in low‐protein fed Sprague‐Dawley rats (Rattus norvegicus) were investigated.A group of male Sprague‐Dawley rats maintained on a low‐protein diet for 5 days were divided into three subgroups. Two subgroups were injected with carbon tetrachloride and the other group with an equivalent amount of olive oil. Two hours after CCl4 intoxication one of the two subgroups was administered with pumpkin seed protein isolate and thereafter switched onto a 20% pumpkin seed protein isolate diet. The other two groups of rats were maintained on the low‐protein diet for the duration of the investigation. Groups of rats from the different subgroups were killed at 24, 48 and 72 h after their respective treatments. After 5 days on the low‐protein diet the activity levels of all the enzymes as well as antioxidant levels were significantly lower than their counterparts on a normal balanced diet. However, a low‐protein diet resulted in significantly increased levels of lipid peroxidation. The CCl4 intoxicated rats responded in a similar way, regarding all the variables investigated, to their counterparts on a low‐protein diet. The administration of pumpkin seed protein isolate after CCl4 intoxication resulted in significantly increased levels of all the variables investigated, with the exception of the lipid peroxidation levels which were significantly decreased. From the results of the present study it is concluded that pumpkin seed protein isolate administration was effective in alleviating the detrimental effects associated with protein malnutrition and CCl4 intoxication. It is therefore apparent that pumpkin seed protein isolate has components that have antiperoxidative properties. Copyright © 2006 John Wiley & Sons, Ltd.
In Vitro evaluation of effects of two ghanaian plants relevant to wound healing
Authors: Mensah Abraham Y. , Houghton Peter J. , Dickson Rita A. , Fleischer T. C. , Heinrich M. , Bremner P. 
Published: August 2006

AbstractCommelina diffusa and Spathodea campanulata are used as wound‐healing agents in Ashanti traditional medicine in Ghana. The methanol extracts of Commelina diffusa herb and Spathodea campanulata bark showed some level of antimicrobial activity with C. diffusa exhibiting selective antifungal activity against Trichophyton species. The extracts reduced the peroxidation of bovine brain extract with an IC50 value of 1.39 mg/mL and 0.24 mg/mL, respectively. In addition the extracts also exhibited significant antioxidant activity by protecting MRC‐5 cells from hydrogen peroxide induced oxidant injury at concentrations between 1 µg/mL and 10 µg/mL. The extracts showed no inhibition of NF‐κB at 100 µg/mL. The antioxidant activities and antimicrobial activities suggest that the use of the plants in wound healing may be based on antioxidant and antiseptic effects of its constituents. Copyright © 2006 John Wiley & Sons, Ltd.
Anticomplement activity of cycloartane glycosides from the rhizome of Cimicifuga foetida
Authors: Qiu Minghua , Kim Jung‐Hee , Lee Hyeong‐Kyu , Min Byung‐Sun 
Published: August 2006

AbstractA tetranor‐cycloartane glycoside and two 9,19‐cycloartane glycosides were isolated from the EtOAc‐soluble fraction of the rhizome of Cimicifuga foetida. The structures of the compounds were determined to be cimilactone A (1), 25‐O‐acetylcimigenol 3‐O‐β‐d‐xylopyranoside (2) and cimigenol 3‐O‐α‐l‐arabinopyranoside (3), respectively, using spectroscopic analysis. The three compounds were examined for their anticomplement activity against the classical pathway of the complement system. Compound 1 showed significant anticomplement activity with an IC50 value of 28.6 µm, whereas compounds 2 and 3 were inactive. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of oriental medicinal herbs for estrogenic and antiproliferative activities
Authors: Kang Se Chan , Lee Chang Min , Choi Han , Lee Jae Hyun , Oh Joa Sub , Kwak Jong Hwan , Zee Ok Pyo 
Published: August 2006

AbstractHerb extracts commercially used in Asia were screened for their estrogenic activity with a recombinant yeast system with both a human estrogen receptor (ER) expression plasmid and a reporter plasmid. Pueraria lobata (flower) had the highest estrogenic relative potency (RP, 17‐estradiol = 1.00) (7.8e‐3) (RP for + control), followed by Amomum xanthioides (1.3e‐3), Glycyrrhiza uralensis, Zingiber officinale, Rheum palmatum, Curcuma aromatica, Eriobotrya japonica, Sophora flavescens, Anemarrhena asphodeloides, Polygonum multiflorum and Pueraria lobata (root) (9.5e‐4–1.0e‐4), and Prunus persica, Lycoppus lucidus and Adenophora stricta (9.0e‐5–8.0e‐5). In the antiproliferative assay, five human cancer cell lines representing different tissues (breast, lung and ovary) were used. Eriobotrya japonica showed strong cytotoxicity in ER‐negative breast cancer (MDA‐MB‐231), cervix epitheloid (HeLa) and lung (A549) carcinoma cell lines. Copyright © 2006 John Wiley & Sons, Ltd.
p90 Ribosomal S6 kinases‐ eclectic members of the human kinome
Authors: Lee Kwok Y. , Bignone Paola A. , Ganesan Trivadi S. 
Published: August 2006

AbstractThe p90 ribosomal S6 kinase (RPS6KA1‐6; RSK1‐6) family represents an important family of conserved serine‐threonine kinases among the higher eukaryotes. RSKs are identified by the presence of two non‐identical and active kinase domains that is unique amongst the kinome. These kinases are involved in a multitude of essential processes in the cell, ranging from apoptosis and transcriptional regulation and activation of immediate early genes to the maintenance of the cell cycle and growth. They are also important in the regulation of the cell cycle in G2, meiosis I and II. The mutation and loss of catalytic activity of RSK2 causes Coffin‐Lowry syndrome. This review provides a concise and focused perspective on the current understanding of the function of RSKs and their substrates.
Soft Lithographic Printing of Patterns of Stretched DNA and DNA/Electronic Polymer Wires by Surface‐Energy Modification and Transfer
Authors: Björk Per , Holmström Sven , Inganäs Olle 
Published: August 2006

AbstractAligned and stretched λ DNA is directed to specific locations on solid substrates. Surface‐energy modification of glass substrates by using patterned polydimethylsiloxane (PDMS) stamps is used to direct DNA onto the surface‐energy‐modified micrometer‐scale pattern through molecular combing. As an alternative, patterned and nonpatterned PDMS stamps modified with polymethylmethacrylate (PMMA) are utilized to direct the stretched DNA to the desired location and the results are compared. The DNA is elongated through molecular combing on the stamp and transfer printed onto the surfaces. PMMA‐modified stamps show a more defined length of the stretched DNA, as compared to bare PDMS stamps. A combination of these two methods is also demonstrated. As an application example, transfer printing of DNA decorated with a semiconducting conjugated polyelectrolyte is shown. The resulting patterned localization of stretched DNA can be utilized for functional nanodevice structures, as well as for biological applications.
Real‐time elastography — an advanced method of ultrasound: first results in 108 patients with breast lesions
Authors: Thomas A. , Fischer T. , Frey H. , Ohlinger R. , Grunwald S. , Blohmer J.‐U. , Winzer K.‐J. , Weber S. , Kristiansen G. , Ebert B. , Kümmel S. 
Published: August 2006

AbstractObjectivesTo evaluate whether real‐time elastography, a new, non‐invasive method for the diagnosis of breast cancer, improves the differentiation and characterization of benign and malignant breast lesions.MethodsReal‐time elastography was carried out in 108 potential breast tumor patients with cytologically or histologically confirmed focal breast lesions (59 benign, 49 malignant; median age, 53.9 years; range, 16–84 years). Tumor and healthy tissue were differentiated by measurement of elasticity based on the correlation between tissue properties and elasticity modulus. Evaluation was performed using the three‐dimensional (3D) finite element method, in which the information is color‐coded and superimposed on the B‐mode ultrasound image. A second observer evaluated the elastography images, in order to improve the objectivity of the method. The results of B‐mode scan and elastography were compared with those of histology and previous sonographic findings. Sensitivities and specificities were calculated, taking histology as the gold standard.ResultsB‐mode ultrasound had a sensitivity of 91.8% and a specificity of 78%, compared with sensitivities of 77.6% and 79.6% and specificities of 91.5% and 84.7%, respectively, for the two observers evaluating elastography. Agreement between B‐mode ultrasound and elastography was good, yielding a weighted kappa of 0.67.ConclusionsOur initial clinical results suggest that real‐time elastography improves the specificity of breast lesion diagnosis and is a promising new approach for the diagnosis of breast cancer. Elastography provides additional information for differentiating malignant BI‐RADS (breast imaging reporting and data system) category IV lesions. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.