bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytoskeletal and nuclear organization in mouse embryos derived from nuclear transfer and ICSI: A comparison of agamogony and syngamy before and during the first cell cycle
Authors: Zhu Zi‐Yu , Jiang Man‐Xi , Yan Li‐Ying , Huang Jun‐Cheng , Lei Zi‐Li , Jiang Yan , Ouyang Ying‐Chun , Zhang Huan‐Xiang , Sun Qing‐Yuan , Chen Da‐Yuan 
Published: October 2006

AbstractIn this study, somatic cell nuclear transfer (SCNT) and intracytoplasmic sperm injection (ICSI) are used as models of agamogony and syngamy, respectively. In order to elucidate the reasons of low efficiency of somatic cell cloning, cytoskeletal and nuclear organization in cloned mouse embryos was monitored before and during the first cell cycle, and compared with the pattern of ICSI zygote. A metaphase‐like spindle with alignment of condensed donor chromosomes was assembled within 3 hr after NT, followed by formation of pronuclear‐like structures at 3–6 hr after activation, indicating that somatic nuclear remodeling depends on microtubular network organization. The percentage of two (pseudo‐) pronuclei in cloned embryos derived from delayed activation was greater than that in immediate activation group (68.5% vs. 30.8%, P < 0.01), but similar to that of ICSI group (68.5% vs. 65.5%, P > 0.05). The 2‐cell rate in NT embryos was significantly lower than that in zygotes produced by ICSI (64.8% vs. 82.5%, P < 0.01). Further studies testified that the cloned embryos reached the metaphase of the first mitosis 10 hr after activation, whereas this occurred at 18 hr in the ICSI zygotes. Comparision of the pattern of microfilament assembly in early NT embryos with that in syngamic zygotes suggested that abnormal microfilamental pattern in cloned embryos may threaten subsequent embryonic development. In conclusion, agamogony, in contrast to syngamy, displays some unique features in respect of cytoskeletal organization, the most remarkable of which is that the first cell cycle is initiated ahead distinctly, which probably leads to incomplete organization of the first mitotic spindle, and contributes to low efficiency of cloning. Mol. Reprod. Dev. 74: 655–663, 2007. © 2006 Wiley‐Liss, Inc.
Exciton luminescence of ZnO fine particles
Authors: Danhara Y. , Hirai T. , Harada Y. , Ohno N. 
Published: October 2006

AbstractPhotoluminescence and time‐resolved photoluminescence spectra of annealed ZnO fine particles with ∼20 nm size have been investigated at 12 K. In unannealed raw ZnO particles, luminescence bands attributed to free‐exciton recombination accompanied by LO phonon emission (LO phonon replica) are dominant in the band‐edge luminescence. For annealed ZnO particles, the intensities of the LO phonon replica become weaker than that of bound exciton band, and the bandwidths of the exciton bands become narrower with the annealing temperature. The time‐resolved luminescence spectra have revealed that the decay times of bound and free excitons become longer for annealed particles. These facts suggest that ZnO particles are aggregated each other even at temperatures well below the melting point. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherence effects in ring molecular systems
Authors: Heřman Pavel , Barvík Ivan 
Published: October 2006

AbstractThe time dependence of the occupation probability decay of optically allowed states in molecular rings (resembling the B850 ring of the purple bacterium Rhodopseudomonas acidophila ‐ nonameric symmetry ‐ and Rhodopseudomonas palustris ‐ octameric symmetry) is calculated. The dipole moments are arranged tangentially in nonameric ring and radially in octameric ring. Fast fluctuations of the environment are simulated by dynamic disorder and slow fluctuations by static disorder. In the present investigation we are comparing results for the time development of the occupation probabilities of optically allowed exciton states P k =±1 (nonameric ring) and P k =±7 (octameric ring) for four models of static disorder: Gaussian disorder in the local energies (Model A), Gaussian disorder in the transfer integrals (Model B), Gaussian disorder in radial positions of molecules (Model C) and Gaussian disorder in angular positions of molecules (Model D). Both types of disorder ‐ static and dynamic ‐ are taken into account simultaneously. We have used Markovian and non‐Markovian treatment of the interaction with the bath. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Model of temperature dependent crystal relaxation
Authors: Mihóková Eva , Schulman Lawrence S. 
Published: October 2006

AbstractAnomalous decay of the slow emission component in certain doped alkali halides was explained by the creation of a discrete breather in the immediate neighborhood of the impurity. It was experimentally observed that with rising temperature the decay anomaly becomes less pronounced, finally disappearing in the range 100 K to150 K (depending on the substance). In view of the breather explanation, this temperature dependence should be a consequence of the effect of temperature on breathers. We present an improved model of the dissipative effects of temperature on lattice breathers so as to compare it to the observed experimental temperature behavior. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Perylene microcrystallites embedded in polyvinyl alcohol fabricated by a precipitation method
Authors: Mizuno K. , Matsubara T. , Aoki‐Matsumoto T. , Ichida M. , Ando H. , Itoh T. 
Published: October 2006

AbstractPerylene microcrystallites with a wide range of the size were fabricated by a precipitation method. The microcrystallite size distribution was well expressed by a Gaussian function. The luminescence spectra and the luminescence decay times were measured at 7∼10 K. The luminescence decay depended strongly on the power of a laser used for photo‐excitation. At weak excitation, the decay exhibited a few nano‐second delay in the rise time but at the intense excitation, a sharp rise and a sharp decay (spike) were observed. Those results suggested the presence of strong interaction among microcrystallites. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coloration dependence in the thermoluminescence properties of the double doped NaCl single crystals under gamma irradiation
Authors: Sánchez‐Mejorada G. , Gelover‐Santiago A. L. , Frias D. 
Published: October 2006

AbstractIn this work the behaviour of calcium manganese doped NaCl single crystals under gamma irradiation is reported. Various single crystals of NaCl doped with Ca and Mn have been irradiated at different doses with ionising radiation. The production of defects has been correlated to the increase in the intensity of the thermo luminescent glow curve as a function of doses. The glow curves intensity as a function of doses shows the potential use of these materials as dosimeters. Optical properties of such crystals after irradiation with gamma rays have also been studied; results have shown their potentiality as a good detector and optical store memory devices. Since the creations of colour centres by photons with energy less than the band gap energy has been detected also in ns2‐ion doped alkali halides. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pro‐inflammatory effects of early non‐enzymatic glycated proteins in human mesothelial cells vary with cell donor's age
Authors: Rodríguez‐Mañas L , Sánchez‐Rodríguez C , Vallejo S , El‐Assar M , Peiró C , Azcutia V , Matesanz N , Sánchez‐Ferrer C F , Nevado J 
Published: October 2006

Background and purpose:Diabetes mellitus is prevalent in the elderly population. It is also a disease causing tissue damage through several different mechanisms. Some of these mechanisms are also activated by ageing and this overlap raises questions about how diabetes induces damage in the elderly. Early products of non‐enzymatic glycation of proteins (Amadori adducts), and the ageing process share the capacity to induce oxidative stress and inflammation in human peritoneal mesothelial cells (HPMCs). We have evaluated the interactions between the age of the donor of the HPMCs and the pro‐inflammatory effects of Amadori adducts in those cells.Experimental approach:HPMCs were isolated from 20 individuals (age range 21–81 years) and grown in culture. Using different experimental approaches we determined NF‐κB dependent transcriptional activity and different NF‐κB‐related pro‐inflammatory gene and protein expressions in basal (or non‐stimulated) conditions and after stimulation with two Amadori adducts; highly‐glycated haemoglobin and glycated bovine serum albumin.Key results:Amadori‐induced effects on NF‐κB dependent‐transcription and on the activity of NOS, COX and several NF‐κB‐related pro‐inflammatory genes (iNOS, COX‐2, TNF‐α, IL‐1β, and IL6) diminished as the donor's age increased, being practically absent in cells from donors more than 65 years old. Such decreased effects were inversely correlated with an increased basal expression and activity of these pro‐inflammatory markers with age.Conclusions and implications:Pro‐inflammatory effects of Amadori‐adducts in HPMCs were strongly dependent on cell donor's age. This may have significant implications for the mechanisms underlying diabetes‐induced tissue damage in patients of different ages.British Journal of Pharmacology (2006) 149, 979–987. doi:10.1038/sj.bjp.0706864
Non‐genomic effect of testosterone on airway smooth muscle
Authors: Kouloumenta V , Hatziefthimiou A , Paraskeva E , Gourgoulianis K , Molyvdas P A 
Published: October 2006

Background and purpose:Recent studies on blood vessels have provided evidence that testosterone may exert direct effects on smooth muscle. However, an acute effect on airway reactivity has not been shown yet. The aim of this study was to assess the direct effect of testosterone on the responsiveness of male adult rabbit airway smooth muscle (ASM), precontracted with 10 μM acetylcholine, 10μM carbachol or 80 mM KCl.Experimental approach:Contractility studies of rabbit tracheal smooth muscle were performed.Key results:Testosterone at concentrations of or above 1 nM had a significant relaxant effect on ASM precontracted with acetylcholine or carbachol, but did not affect ASM precontracted with KCl. The mechanical removal of airway epithelium as well as the inhibition of NO synthetase (by 100μM L‐NAME) reduced the relaxation caused by testosterone. The effect of testosterone was not altered by impairing prostanoid synthesis (by 10μM indomethacin). The nitric oxide donor, sodium nitroprusside, had the same relaxant effect on ASM precontracted with either carbachol or KCl. Inhibitors of androgen receptors (10μM flutamide) or DNA transcription (100μM actinomycin D) did not alter the effect of testosterone. Prolonged incubation of ASM with 100 nM or 100 μM testosterone for 24 or 48 h did not alter their responsiveness to acetylcholine. BSA‐testosterone (1pM to 100nM) relaxed significantly ASM precontracted with carbachol. The mechanical removal of airway epithelium abolished the relaxant effect of BSA‐testosterone.Conclusions and implications:Testosterone relaxes precontracted ASM via an epithelium and NO‐mediated way. This effect is mediated via a non‐genomic pathway.British Journal of Pharmacology(2006)149, 1083–1091. doi:10.1038/sj.bjp.0706936
In vivopharmacological resultant analysis reveals noncompetitive interactions between opioid antagonists in the rat tail‐withdrawal assay
Authors: Walker E A 
Published: October 2006

Background and purpose:Pharmacological resultant analysis is a technique that can detect secondary effects of competitive antagonistsin vitro. The utility of pharmacological resultant analysis as a potential tool for the investigation of antagonist interactionsin vivowas examined in the present study using two opioid antagonists, naltrexone and CTAP.Experimental approach:Using the experimental design of pharmacological resultant analysis, the well‐characterized opioid antagonist naltrexone was examined in the presence of multiple doses of CTAP to block the antinociceptive effects of morphine in the rat warm‐water (55oC), tail‐withdrawal assay.Key results:Alone, all doses of naltrexone, CTAP, and CTOP examined blocked the antinociceptive effects of morphine. In the presence of fixed doses of 1 or 10 μg CTAP, increasing doses of naltrexone produced dose‐dependent shifts to the right in the morphine dose‐response curve. However, a lower dose of naltrexone in combination with 1 or 10 μg CTAP failed to alter the morphine dose‐response curve. In the presence of a fixed dose of 0.1 mg kg−1naltrexone, CTAP doses produced irregular shifts to the right in the morphine dose‐response curves.Conclusions and implications:Resultant analysis was applied and an apparent pKCvalue for CTAP was found to be one log unit higher than the apparent pA2value for CTAP, evidence that CTAP may have secondary actions or that a signal transducer function may be altered by the combinations of these antagonists. Taken together, these data suggest pharmacological resultant analysis can reveal novel interactions between antagonistsin vivo.British Journal of Pharmacology(2006)149, 1071–1082. doi:10.1038/sj.bjp.0706946
Supporting students to develop collaborative learning skills in technology‐based environments
Authors: Nevgi Anne , Virtanen Päivi , Niemi Hannele 
Published: October 2006

AbstractThe paper focuses on the question of how to advance collaboration through the Web and support lifelong learning. First, the theoretical framework and architecture of a new web‐based tool, the ‘IQ Team’, is introduced. IQ Team is an interactive online assessment and support system to learn social skills needed in cooperative work, and belongs in an interactive online assessing and tutoring system, ‘IQ Form’, developed for the Finnish Virtual University. IQ Team has three main elements: (1) interactive self‐evaluation test banks, (2) online tutoring sets and (3) learning diaries. In the creation of IQ Team, the validation process was conducted with two samples (n = 259 andn = 275). The online students’ social skills in different groups were explored, and the feedback data from different user groups were analysed. The online students scored high values for social skills, and no differences were discerned between university, Open University and technical students. The qualitative data (n = 35) were collected in order to get users’ feedback of the tool. The qualitative data consisted of interviews, open‐ended questions and online discussions. The users of IQ Team reflected that the tool benefited them to become aware of their group work skills and developed their collaborative learning skills. IQ Team provides a powerful tool for online instruction and communication in higher education and in the Open University to promote joint‐regulated learning.
Bypassing of a polygenicMicrocyclus uleiresistance in rubber tree, analyzed by QTL detection
Authors: Le Guen V. , Garcia D. , Mattos C. R. R. , Doaré F. , Lespinasse D. , Seguin M. 
Published: October 2006

SummaryGenetic resistance components of theHevea brasiliensis × H. benthamianaRO 38 cultivar toMicrocyclus uleidisease were investigated by inoculating isolates which succeeded in partially or completely infecting genotypes of a mapping population.Progeny of a cross between RO 38 and a susceptible cultivar was inoculated under controlled conditions with three isolates and scored for two resistance traits. Interval mapping and a nonparametric test were used to detect resistance quantitative trait loci (QTLs).Eight significant QTLs were detected, all of them inherited from the interspecific parent. Among these QTLs, only one contributed to the partial resistance against a highly pathogenic isolate, and no QTL was detected for resistance against the most pathogenic isolate. As an unexpected result, a single isolate can thus completely bypass this polygenic resistance.This complex situation, where no clear relationship can be established between number of resistance factors and qualitative vs quantitative or partial vs complete resistance, is discussed and suggestions as to the detection of new and sustainable resistance sources are proposed.
Soil physical fertility, soil structure and rooting conditions after ploughing organically managed grass/clover swards
Authors: Ball B. C. , Watson C. A. , Baddeley J. A. 
Published: October 2006

AbstractEffective management of soil structure and organic matter are essential in organic cropping to ensure good rooting conditions and to optimize the production of mineralized N and thus minimize greenhouse gas emissions. We investigated how mid‐winter or early spring ploughing and three grazing duration treatments prior to ploughing influenced soil structure, soil organic matter and plant root growth under the first spring barley crop after a grass–clover ley. The experiment was carried out over two seasons. We also studied the soil under first‐year oats in a long‐term rotations experiment where 2 or 3 years of arable crops followed 3 or 4 years of grass. Pore size distribution and pore continuity, bulk density, particulate (light fraction) organic matter, readily oxidizable organic matter (ROM), aggregate size distribution and root length densities were measured. Macroporosity appeared to be the best indicator of soil physical fertility; it was sensitive to changes in soil structure arising from compaction and root growth. This, along with visual examination, revealed the loosening resulting from ploughing. The generally favourable macroporosity amongst small, stable aggregates reduced the likelihood of development of anaerobism. Macroporosity and aggregate size can be estimated from visual examination of the soil, a method that offers the advantage of being quick and of sampling a large volume. The content of ROM was high 6.1–6.4 g 100 g−1 whole soil. However, particulates formed only a small fraction (6–9%) of the ROM. Despite the favourable ROM and structure, the soil was susceptible to compaction damage during seedbed preparation in wet soil after ploughing which reduced grain yield in some plots. Grazing by sheep before ploughing and date of ploughing had minor effects on soil quality. Grazing for 2 months prior to ploughing increased root length density in the upper topsoil in the following arable crop, possibly because of the higher quality of the animal and grass–clover residues. Conservation of soil quality was related more to secondary tillage and sowing operations after ploughing than to duration and timing of grazing.
The Marius Implant Bridge: Surgical and Prosthetic Rehabilitation for the Completely Edentulous Upper Jaw with Moderate to Severe Resorption: A 5‐Year Retrospective Clinical Study
Authors: Fortin Yvan , Sullivan Richard M. , Rangert Bo R. 
Published: October 2006

ABSTRACT Background: Patients seeking replacement of their upper denture with an implant‐supported restoration are most interested in a fixed restoration. Accompanying the loss of supporting alveolar structure due to resorption is the necessity for lip support, often provided by a denture flange. Attempts to provide a fixed restoration can result in compromises to oral hygiene based on designs with ridge laps. An alternative has been an overdenture prosthesis, which provides lip support but has extensions on to the palate and considerations of patient acceptance. The Marius bridge was developed as a fixed bridge alternative offering lip support that is removable by the patient for hygiene purposes, with no palatal extension beyond normal crown‐alveolar contours. Purpose: Implant‐supported restorative treatment of completely edentulous upper jaws, as an alternative to a complete denture, is frequently an elective preference, and it requires significant patient acceptance beyond the functional improvement of chewing. Patients with moderate to severe bone resorption and thin ridges present additional challenges for adequate bone volume and soft‐tissue contours. The purpose of this investigation was to develop a surgical and prosthetic implant treatment protocol for completely edentulous maxillae in which optimal lip support and phonetics is achieved in combination with substantial implant anchorage without bone grafting. Materials and Methods: The Marius bridge is a complete‐arch, double‐structure prosthesis for maxillae that is removable by the patient for oral hygiene. The first 45 consecutive patients treated by one person (YF) in one center with this concept are reported, with 245 implants followed for up to 5 years after prostheses connection. Results: The cumulative fixture survival rate for this 5‐year retrospective clinical study was 97%. Five fixtures failed before loading, in five different patients, and two fixtures in the same patient failed at the 3‐year follow‐up visit. None of the bridges failed, giving a prostheses survival rate of 100%. The complications were few and mainly prosthetic: nine incidences of attachment component complications, one mesobar fracture, and three reports of gingivitis. All complications were solved or repaired immediately, with minimal or no interruption of prostheses use. Conclusions: Satisfactory medium‐term results of survival and patient satisfaction show that the Marius bridge can be recommended for implant dentistry. The technique may reduce the need for grafting, because it allows for longer implants to be placed with improved bone anchorage and prostheses support.
Immediate Loading of Brånemark Implants: a 24‐Month Follow‐Up of a Comparative Prospective Pilot Study between Mandibular Overdentures Supported by Conical® Transmucosal and Standard MK II Implants
Authors: Gatti Claudio , Chiapasco Matteo 
Published: October 2006

ABSTRACT Background: The purpose of this prospective study is to compare the long‐term outcome of immediately loaded implantretained mandibular overdentures supported by four screw‐type one‐piece transmucosal implants with that of four screw‐type two‐piece implants inserted in the interforaminal area of the mandible and rigidly connected by a U‐shaped curved Materials and Methods: A prospective pilot study was conducted with 10 patients receiving an implant‐supported overdenture in the mandible. The patients were randomly assigned to two groups. In the control group (five patients), four standard Brånemark implants (MK II; Nobel Biocare AB, Gothenburg, Sweden), 3.75 mm large and at least 10 mm long, were sited anterior to the mental foramina, and four standard abutments (Nobel Biocare AB) for bar construction were immediately screwed to the implants. In the test group (five patients), four conical transmucosal implants (Nobel Biocare AB), 3.75 mm large and at least 9 mm long in the threaded part, were sited anterior to the mental foramina. Immediately after implant placement, a U‐shaped gold or titanium bar was fabricated and implants were immediately loaded (within 24 h) in both groups with an implant‐retained overdenture. The patients were followed up for a minimum of 24 months. Implants were evaluated at the time of immediate loading and at 12 and 24 months after prosthetic loading, with the following parameters: modified plaque index (MPI), modified bleeding index (MBI), and probing depth (PD). Periimplant bone resorption was evaluated on panoramic radiographs taken 12 and 24 months after the beginning of prosthetic loading. Results: No significant differences were found between the two groups with regard to MPI, MBI, PD, and periimplant bone resorption at 12 and 24 months. The cumulative success rate of implants according to the criteria proposed by Albrektsson and colleagues was 100% in both groups after 2 years of functional loading. Conclusions: Results from this study demonstrated that the success rate for immediately loaded mandibular implants is similar to that obtained in cases of delayed loading and that there are no significant differences between results with two‐piece implants and one‐piece transmucosal implants.