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FT
Selected AbstractsPerformance comparison of MPI and OpenMP on shared memory multiprocessorsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 1 2006Géraud Krawezik Abstract When using a shared memory multiprocessor, the programmer faces the issue of selecting the portable programming model which will provide the best performance. Even if they restricts their choice to the standard programming environments (MPI and OpenMP), they have to select a programming approach among MPI and the variety of OpenMP programming styles. To help the programmer in their decision, we compare MPI with three OpenMP programming styles (loop level, loop level with large parallel sections, SPMD) using a subset of the NAS benchmark (CG, MG, FT, LU), two dataset sizes (A and B), and two shared memory multiprocessors (IBM SP3 NightHawk II, SGI Origin 3800). We have developed the first SPMD OpenMP version of the NAS benchmark and gathered other OpenMP versions from independent sources (PBN, SDSC and RWCP). Experimental results demonstrate that OpenMP provides competitive performance compared with MPI for a large set of experimental conditions. Not surprisingly, the two best OpenMP versions are those requiring the strongest programming effort. MPI still provides the best performance under some conditions. We present breakdowns of the execution times and measurements of hardware performance counters to explain the performance differences. Copyright © 2005 John Wiley & Sons, Ltd. [source] Preparation and characterization of ZnO nanofibers by electrospinningCRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2006R. Siddheswaran Abstract Electrospun ZnO nanofibers were obtained by calcinating PVA/Zinc Acetate composite fibers at various temperatures. Atomic Force Microscopy (AFM) revealed that the ZnO fibers have diameters in the range of 100-200 nm. The fibers were characterized by FT- IR, TGA-DTA, and XRD studies. The XRD results showed that the crystal structure and the morphology of the fibers were largely dependent on the calcination temperature (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Vibration signals from the FT joint can induce phase transitions in both directions in motoneuron pools of the stick insect walking systemDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2003Ulrich Bässler Abstract The influence of vibratory signals from the femoral chordotonal organ fCO on the activities of muscles and motoneurons in the three main leg joints of the stick insect leg, i.e., the thoraco,coxal (TC) joint, the coxa,trochanteral (CT) joint, and the femur,tibia (FT) joint, was investigated when the animal was in the active behavioral state. Vibration stimuli induced a switch in motor activity (phase transition), for example, in the FT joint motor activity switched from flexor tibiae to extensor tibiae or vice versa. Similarly, fCO vibration induced phase transitions in both directions between the motoneuron pools of the TC joint and the CT joint. There was no correlation between the directions of phase transition in different joints. Vibration stimuli presented during simultaneous fCO elongation terminated the reflex reversal motor pattern in the FT joint prematurely by activating extensor and inactivating flexor tibiae motoneurons. In legs with freely moving tibia, fCO vibration promoted phase transitions in tibial movement. Furthermore, ground vibration promoted stance,swing transitions as long as the leg was not close to its anterior extreme position during stepping. Our results provide evidence that, in the active behavioral state of the stick insect, vibration signals can access the rhythm generating or bistable networks of the three main leg joints and can promote phase transitions in motor activity in both directions. The results substantiate earlier findings on the modular structure of the single-leg walking pattern generator and indicate a new mechanism of how sensory influence can contribute to the synchronization of phase transitions in adjacent leg joints independent of the walking direction. © 2003 Wiley Periodicals, Inc. J Neurobiol 56: 125,138, 2003 [source] Spontaneous kicking in full-term and preterm infants with and without white matter disorderDEVELOPMENTAL PSYCHOBIOLOGY, Issue 6 2010Linda Fetters Abstract Early damage to white matter of the brain may have developmental consequences for prematurely born infants including the coordination of leg movements. Our perspective is that white matter damage initiates an ontogenetic course that may lead to movement dysfunction leading to disability. In this study, spontaneous kicking in the human infant is a "window" for evaluating the potential consequences of perinatal brain damage for sensori-motor coordination. We compare the intra-limb coordination patterns of 5-month-old premature infants with white matter damage (PTWMD) to a group of prematurely born infants without WMD (PT) and a group of full-term (FT) infants. The PT group demonstrates advanced kicking patterns in comparison to both the PTWMD and FT groups. The PTWMD group has less mature patterns than the FT group on some, but not all measures. The movement challenge for PTWMD infants may be in the transition from spontaneous kicking to movements with the legs that require decoupling of intralimb joints. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 524,536, 2010. [source] Immunization with heat-killed Francisella tularensis LVS elicits protective antibody-mediated immunityEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2007Christy Abstract Francisella tularensis (FT) has been classified by the CDC as a category,A pathogen because of its high virulence and the high mortality rate associated with infection via the aerosol route. Because there is no licensed vaccine available for FT, development of prophylactic and therapeutic regimens for the prevention/treatment of infection is a high priority. In this report, heat-killed FT live vaccine strain (HKLVS) was employed as a vaccine immunogen, either alone or in combination with an adjuvant, and was found to elicit protective immunity against high-dose FT live vaccine strain (FTLVS) challenge. FT-specific antibodies produced in response to immunization with HKLVS alone were subsequently found to completely protect naive mice against high-dose FT challenge in both infection-interference and passive immunization experiments. Additional passive immunization trials employing serum collected from mice immunized with a heat-killed preparation of an O-antigen-deficient transposon mutant of FTLVS (HKLVS-OAgneg) yielded similar results. These findings demonstrated that FT-specific antibodies alone can confer immunity against high-dose FTLVS challenge, and they reveal that antibody-mediated protection is not dependent upon production of LPS-specific antibodies. [source] Spectroscopic investigation of the function of aqueous 2-hydroxyethylmethacrylate/glutaraldehyde solution as a dentin desensitizerEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2006Chuangye Qin Fourier-transform (FT)-Raman and -infrared (IR) spectroscopy were employed to investigate the function of the aqueous 2-hydroxyethylmethacrylate/glutaraldehyde solution (Gluma) as a desensitizer. 2-Hydroxyethylmethacrylate (HEMA), glutaraldehyde (GA), and the mixture of HEMA/GA (i.e. Gluma) were used to interact with dentin, collagen, hydroxyapatite (HAP), and bovine serum albumin (BSA) individually. All the interactions were monitored by an FT-Raman spectrometer. FT-IR spectroscopy was also used in this study. The results show that HEMA could be absorbed by dentin and collagen; GA could cross-link collagen and BSA; and when BSA was added to Gluma, polymerization of HEMA occurred. The results suggest that Gluma acts as a desensitizer whereby, first, GA reacts with part of the serum albumin in dentinal fluid, which induces a precipitation of serum albumin, then, second, a reaction of GA with serum albumin induces polymerization of HEMA. The function of Gluma as a desensitizer to block dentinal tubules occurs via these two reactions. [source] Financial Times Business School Rankings: A Nontraditional Assurance Case in Three Parts,ACCOUNTING PERSPECTIVES, Issue 1 2007Andrea B. Davies ABSTRACT The Financial Times of London (FT) is a business newspaper, with daily editions published in the United Kingdom, continental Europe, the United States, and Asia, and an estimated daily readership of 10 million people. In 1999 the FT began to publish a ranking of what it considered to be the top business schools in the world. Since their inception, these rankings have become increasingly relied upon by potential students and business school administrators worldwide. The FT's ranking is unique compared with other rankings because of its special international focus. Given the prominence of these rankings and the FT's position as a well-respected business newspaper, the question of providing assurance over the business school rankings that the FT provides is particularly challenging. [source] Dental pulp fibroblasts express neuropeptide Y Y1 receptor but not neuropeptide YINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2010S. A. Killough Killough SA, Lundy FT, Irwin CR. Dental pulp fibroblasts express neuropeptide Y Y1 receptor but not neuropeptide Y. International Endodontic Journal, 43, 835,842, 2010. Abstract Aim, To investigate whether dental pulp fibroblasts express neuropeptide Y (NPY) and NPY-Y1 in vitro and to determine the effects of the cytokines including interlukin-1, (IL-1,), TGF- ,1, substance P and NPY on the expression of NPY Y1. Methodology, Three primary fibroblast cell strains were obtained from freshly extracted human third molar teeth. RT-PCR was utilized to detect expression of NPY and mRNA expression. Membrane protein samples were isolated, and protein expression was determined by Western blotting. Radioimmunoassay was used to quantify NPY expression in healthy (n = 35) and carious (n = 39) whole pulp samples, and the student's t -test was used to test for statistical significance. In addition, the 3-(4,5-Dimethylthiazol,2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assay fibroblast cell growth. Results, mRNA transcripts were found in all three fibroblast cell populations with the cytokines having a stimulatory effect on its expression (P < 0.05). NPY mRNA was not detected in the cell strains. NPY-Y1 receptor protein expression was visualized by Western blotting, and there was no effect of IL-1, or TGF- ,1 on its expression. The mean concentration of NPY-Ir determined by radioimmunoassay in non-carious teeth was 19.40 ng g,1 (±17.03 SD) compared to 29.95 ng g,1 (±20.99 SD) in carious teeth (P < 0.05). Conclusion, Human dental pulp fibroblasts express, but do not synthesize, NPY, demonstrating that the fibroblast is a target cell for NPY. The effect of proinflammatory cytokines suggests that fibroblasts play a neuroimmunomodulatory role in the pulpal response to dental caries and injury. [source] Expression and enzyme activity of ,(1,6)fucosyltransferase in human colorectal cancerINTERNATIONAL JOURNAL OF CANCER, Issue 3 2008Laura Muinelo-Romay Abstract Changes in enzyme activity and the expression levels of ,(1,6)fucosyltransferase [,(1,6)FT] have been reported in certain types of malignant transformations. To develop a better understanding of the role of ,(1,6)FT in human colorectal carcinoma (CRC), we analysed the enzyme activity in healthy and tumour tissues. ,(1,6)FT activity was considerably higher in tumour tissue than in healthy tissue and was related to gender, lymph node metastasis, type of growth and tumour stage. We also observed a significant increase in the ,(1,6)FT expression in tumour tissues as compared to healthy and transitional tissues, inflammatory lesions and adenomas. The immunohistochemical expression in tumour tissues was correlated with the degree of infiltration through the intestinal wall. Finally, a statistical correlation was found between enzyme activity and expression obtained by Western blot in colorectal tumours when compared in the same patient. All these findings demonstrate an alteration of ,(1,6)FT activity and expression in CRC. © 2008 Wiley-Liss, Inc. [source] Thermal anomaly around the Nojima Fault as detected by fission-track analysis of Ogura 500 m borehole samplesISLAND ARC, Issue 3-4 2001Takahiro Tagami Abstract To better understand heat generation and transfer along earthquake faults, this paper presents preliminary zircon fission-track (FT) length data from the Nojima Fault, Awaji Island, Japan, which was activated during the 1995 Kobe earthquake (Hyogo-ken Nanbu earthquake). Samples were collected of Cretaceous granitic rocks from the Ogura 500 m borehole as well as at outcrops adjacent to the borehole site. The Nojima Fault plane was drilled at a depth of 389.4 m (borehole apparent depth). Fission-track lengths in zircons from localities > 60 m distance from the fault plane, as well as those from outcrops, are characterized by the mean values of ,10,11 ,m and unimodal distributions with positive skewness, which show no signs of an appreciable reduction in FT length. In contrast, those from nearby the fault at depths show significantly reduced mean track lengths of ,6,8 ,m and distributions having a peak around 6,7 ,m with rather negative skewness. In conjunction with other geological constraints, these results are best interpreted by a recent thermal anomaly around the fault, which is attributable to heat transfer via focused fluids from the deep interior of the crust and/or heat dispersion via fluids associated with frictional heating by fault motion. [source] Research Article: Fingerprinting Analysis of Saposhnikovia divaricata using 1H Nuclear Magnetic Resonance Spectroscopy and High Performance Liquid ChromatographyJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2010Yue-Yang Xin The 1H nuclear magnetic resonance (1H NMR) fingerprints of fractionated non-polar and polar extracts (control substance for plant drug [CSPD] A and B) from the roots of 12 specimens of Saposhnikovia divaricata (Turcz.) Schischk were achieved with Fourier Transform (FT)-NMR spectrometer and assigned by comparison to each other and to the 1H NMR spectra of the isolated individual compounds. These fingerprints were found to be uniform in terms of the specificity for the implication of all 12 specimens being systematically of the same origin. The uniformity was further affirmed by high performance liquid chromatography (HPLC), which also revealed exactly identical specificity for the identified S. divaricata species with the 1H NMR appearances of corresponding CSPD on the part of the composition of characteristic constituents when comparing to corresponding individual compounds. This investigation unambiguously shows that the specific signals from the chemotaxonomically significant compounds of chromones and coumarins in S. divaricata are exhibited distinctively in the composite features of both 1H NMR fingerprints and HPLC profiles. The 1H NMR and HPLC profiles established can successfully be used as reference for the authentication of the origin of S. divaricata species as well as for chemotaxonomic studies. [source] Fingerprinting Analysis of Rhizoma Chuanxiong of Commercial Types using 1H Nuclear Magnetic Resonance Spectroscopy and High Performance Liquid Chromatography MethodJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 6 2009Hai-Lin Qin Abstract The 1H nuclear magnetic resonance (1H NMR) fingerprints of fractionated non-polar extracts (control substance for a plant drug (CSPD) A) from Rhizoma chuanxiong, the rhizomes of Ligusticum chuanxiong Hort., of seven specimens from different sources were measured on Fourier Transform (FT)-NMR spectrometer and assigned by comparing them with the 1H NMR spectra of the isolated pure compounds. The 1H NMR fingerprints showed exclusively characteristic resonance signals of the major special constituents of the plant. Although the differences in the relative intensity of the 1H NMR signals due to a discrepancy in the ratio of the major constituents among these samples could be confirmed by high performance liquid chromatography analysis, the general features of the 1H NMR fingerprint established for an authentic sample of the rhizomes of L. chuanxiong exhibited exclusive data from those special compounds and can be used for authenticating L. Chuanxiong species. [source] Florigen (II): It is a Mobile ProteinJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2007Yuejun Yang Abstract The true identity of florigen , the molecule(s) that migrates from leaves to apical meristem to initiate flowering , was notoriously elusive, having made it almost the "Bigfoot" of plant biology. There was never a lack of drama in the field of florigen study, and florigen researchers have once again experienced such a swing in the last two years. We wrote a minireview last year in this journal (Yu et al. 2006) to excitedly salute, among other discoveries, the notion that the flowering locus T (FT) mRNA might be the molecular form of a florigen. However, this hypothesis was challenged in a little less than two years after its initial proposition, and the original paper proposed that the FT mRNA hypothesis was retracted (Huang et al. 2005; Bohlenius et al. 2007). Interestingly enough, the FT gene previously proposed to encode a florigen was never challenged. Rather, the FT protein, instead of the FT mRNA, is now believed to migrate from leaves to the apical meristem to promote floral initiation. In this update, we will share with our readers some entertaining stories concerning the recent studies of florigen in five different plant species. In addition to the published reports referenced in this update, readers may also refer to our previous minireview and references therein for additional background information (Yu et al. 2006). [source] Vibrational spectra of the layered monofluorophosphate (V), NH4Ag3(PO3F)2JOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2009Enrique J. Baran Abstract The powder Fourier-transform (FT) infrared (IR) and Raman spectra of the recently characterized NH4Ag3(PO3F)2 were recorded and are discussed with a site-symmetry analysis based on its known structural data. Some comparisons are made with the solution spectra of the PO3F2, anion and with those of crystalline Ag2PO3F. Copyright © 2009 John Wiley & Sons, Ltd. [source] Vibrational spectroscopy investigation using density functional theory on 7-chloro-3-methyl-2H-1,2,4- benzothiadiazine 1,1-dioxideJOURNAL OF RAMAN SPECTROSCOPY, Issue 6 2009S. Seshadri Abstract The solid phase Fourier transform infrared (FTIR) and Fourier transform (FT) Raman spectral analysis of 7-chloro-3-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide (diazoxide), an antihypertensive agent was carried out along with density functional computations. The optimized geometry, wavenumber and intensity of the vibrational bands of diazoxide were obtained by DFT-B3LYP level of theory with complete relaxation in the potential energy surface using 6-31G(d,p) basis set. A complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed. The harmonic vibrational wavenumbers calculated have been compared with experimental FTIR and FT Raman spectra. The observed and the calculated wavenumbers are found to be in good agreement. The experimental spectra coincide satisfactorily with those of calculated spectra. Copyright © 2009 John Wiley & Sons, Ltd. [source] Vibrational spectra and quantum chemical calculations of uracilyl,pyridinium mesomeric betaineJOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2007A. Schmidt Abstract Modified nucleobases (MNs) are promising molecules with potential application in non-linear optic (NLO) and drug design against a wide number of diseases. In the present paper we report studies on a cross-conjugated mesomeric betaine, which can act as a MN, formed by the covalent union of a 4-dimethylamino pyridinium and a uracilyl groups. The molecule thus formed must be presented by a dipolar canonical formulae in which positive and negative charges are delocalized within separated moieties. Quantum chemistry density functional theory (DFT) calculations, at the B3PW91/6-31G** level, and Fourier transform (FT) infrared and Raman spectra of this molecule and its N -deuterated derivative were performed. The calculated structural properties over the ground state optimized structure evidenced a strong separation between the two conjugated systems. Comparison with previous results obtained for the cationic species indicated that N -protonation clearly affects the degree of conjugation. Assignments of the FT-IR and FT-Raman spectra were supported by the DFT wavenumbers, intensities and normal modes, which also evidenced the separation of the two conjugated systems. Significant deviations were found for the stretching force constants of the inter-ring and the uracilyl skeletal bonds when comparing this molecule with its N -protonated species. Copyright © 2007 John Wiley & Sons, Ltd. [source] Vibrational spectra of three new diarsenates containing scandium(III)JOURNAL OF RAMAN SPECTROSCOPY, Issue 12 2006Enrique J. Baran Abstract The powder Fourier transform (FT) infrared and Raman spectra of the new isotypic diarsenates RbScAs2O7, TlScAs2O7, and (NH4)ScAs2O7 are discussed with a factor group analysis, on the basis of their known structural characteristics. The spectroscopic behavior clearly reflects all the structural peculiarities and also confirms the rotational quenching of the NH4+ cation in (NH4) ScAs2O7. The crystal structure of TlScAs2O7 is also reported for the first time and is briefly discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source] In vitro and in vivo identification of ,pseudocatalase' activity in Dead Sea water using Fourier transform Raman spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2002Karin U. Schallreuter Balneotherapy with Dead Sea water has been reported as a successful treatment modality for psoriasis, atopic eczema and vitiligo, but the precise mode of action has escaped definition so far. The saturating salt concentration (346 g/litre) together with the unique UV spectrum have been suggested to trigger the release of pro-inflammatory and chemotactic mediators. The results of our study show for the first time a high content of transition metal ions (manganese, iron and copper) in Dead Sea water. Using in vitro Fourier transform (FT) Raman spectroscopy, we were able to identify ,pseudocatalase' activity by observing the decomposition of hydrogen peroxide (H2O2) over time by Dead Sea water. Since patients with vitiligo accumulate millimolar levels of H2O2 in their skin, we followed the degradation of H2O2in vivo again utilizing the same technique. The results of this in vitro and in vivo study show for the first time a ,pseudocatalase' activity of Dead Sea water and provide evidence that the antioxidant properties of Dead Sea water bathing could play an important role in this unique treatment modality. Furthermore, the use of non-invasive in vivo FT-Raman spectroscopy introduces an excellent biomedical application in investigative dermatology. Copyright © 2002 John Wiley & Sons, Ltd. [source] Fourier transform Raman spectroscopic study of pigments present in decorative wallpapers of the middle nineteenth century from the Santa Isabel factory (Vitoria, Basque Country, Spain),JOURNAL OF RAMAN SPECTROSCOPY, Issue 1 2002K. Castro One of the earliest wallpapers manufactured by the Santa Isabel factory (Vitoria, Basque Country, Spain) (1845) was found at the Torre de los Varona (near Vitoria) during restoration work on the building. As part of this cleaning and restoration work, the identification of the wallpaper's pigments was carried out by Fourier transform (FT) Raman spectroscopy. Fragments of paper were set in a sampler kit for planar surfaces. By moving the paper samples, it is possible to locate the laser beam's spot at the point that it is going to be analysed with a spatial resolution of about 0.5 mm. With this method it is possible to map a surface of several square centimetres without the need for an optical microscope. As FT-Raman analysis is totally non-destructive, the samples were restored and integrated with the whole wallpaper at the end of the analysis. Small particles of pigment were collected for the analysis of the pink and green colours by atomic absorption spectrometry (AAS). In both cases, the damage caused by the pigment sampling was minimal and non-visible. BaSO4, CaCO3, Pb3O4, PbCrO4, PbO, Prussian Blue, gypsum and an organic black pigment were detected. It is important to take into account the laser beam's penetrative power in order to interpret the spectra correctly. The identification of only eight pigments to make 12 different colours, mostly in two different shades, shows the ability of the wallpaper manufacturer to create a rich palette at low cost. This type of primitive industrial decorative work has become real artwork that it is necessary to preserve and restore. Copyright © 2002 John Wiley & Sons, Ltd. [source] Spectroscopic studies on interactions and microstructures in propylene carbonate,LiTFSI electrolytesJOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2001Zhaoxiang Wang Interactions between propylene carbonate (PC) and lithium bis(trifluoromethane sulfone imide) [LiTFSI, LiN(CF3SO2)2] were studied by Fourier transform (FT) Raman and IR spectroscopy. It was found that PC interacts with the Li+ ions and the TFSI, anions through its skeletal oxygen atoms, leading to solvent-separated ion pairs and contact ion pairs in the solution by way of the nitrogen atoms on the anion. Copyright © 2001 John Wiley & Sons, Ltd. [source] Effects of Neuropeptide Y on Appetitive and Consummatory Behaviors Associated With Alcohol Drinking in Wistar Rats With a History of Ethanol ExposureALCOHOLISM, Issue 4 2005Annika Thorsell Background: Neuropeptide Y (NPY) reduces ethanol intake under free access conditions in Wistar rats with a history of prolonged ethanol vapor exposure. The current study was designed to determine whether NPY differentially alters ethanol-associated appetitive behavior (i.e., lever pressing) or ethanol consumption in Wistar rats with a history of ethanol vapor exposure. Methods: Wistar rats were first trained to self-administer 10% ethanol in a paradigm that provided 25 min of free access to 10% ethanol after completing a 20,lever press response requirement (i.e., an RR20 schedule). After stable level lever pressing was established, operant sessions were suspended during a 9-week period of ethanol vapor exposure. Self-administration sessions were then reinstituted, and a fixed time (FT) schedule of 10% ethanol access was used to assess the effects of ethanol exposure and NPY on lever pressing and drinking behavior. Under the FT schedule, the maximum number of lever presses emitted within 10 min was assessed before providing access to 10% ethanol. Results: Ethanol vapor exposure did not alter patterns of lever pressing under the RR20 schedule, but lever presses emitted under the FT schedule were reduced after ethanol vapor exposure. Ethanol intake was significantly increased after ethanol vapor exposure. NPY significantly reduced ethanol intake but did not significantly reduce lever pressing under the FT schedule. Conclusions: Taken together, these data suggest that chronic ethanol exposure increases ethanol intake without clearly enhancing its reinforcing value. Furthermore, NPY has a greater impact on the consummatory factors mediating ethanol intake than appetitive factors mediating ethanol seeking. [source] Induction and Maintenance of Ethanol Self-Administration in Cynomolgus Monkeys (Macaca fascicularis): Long-Term Characterization of Sex and Individual DifferencesALCOHOLISM, Issue 8 2001J. A. Vivian Background: Investigations of oral ethanol self-administration in nonhuman primates have revealed important parallels with human alcohol use and abuse, yet many fundamental questions concerning the individual risk to, and the biological basis of, excessive ethanol consumption remain unanswered. Moreover, many conditions of access to ethanol in nonhuman primate research are largely unexplored. This set of experiments extends within- and across-session exposure to ethanol to more fully characterize individual differences in oral ethanol self-administration. Methods: Eight male and eight female adult cynomolgus monkeys (Macaca fascicularis) were exposed to daily oral ethanol self-administration sessions for approximately 9 months. During the first 3 months, a fixed-time (FT) schedule of food delivery was used to induce the consumption of an allotted dose of ethanol in 16-hr sessions. Subsequently, the FT schedule was suspended, and ethanol was available ad libitum for 6 months in 16- or 22-hr sessions. Results: Cynomolgus monkeys varied greatly in their propensity to self-administer ethanol, with sex and individual differences apparent within 10 days of ethanol exposure. Over the last 3 months of ethanol access, individual average ethanol intakes ranged from 0.6 to 4.0 g/kg/day, resulting in blood ethanol concentrations from 5 to 235 mg/dl. Males drank approximately 1.5-fold more than females. In addition, heavy-, moderate-, and light-drinking phenotypes were identified by using daily ethanol intake and the percentage of daily calories obtained from ethanol as criteria. Conclusions: Cynomolgus monkeys displayed a wide intersubject range of oral ethanol self-administration with a procedure that used a uniform and prolonged induction that restricted early exposure to ethanol and subsequently allowed unlimited access to ethanol. There were sex and stable individual differences in the propensity of monkeys to consume ethanol, indicating that this species will be important in characterizing risk factors associated with heavy-drinking phenotypes. [source] Effect of CaF2 and CaO Substituted for MgO on the Phase Evolution and Mechanical Properties of K-Fluorrichterite Glass CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2006Mehdi Mirsaneh Chain silicate glass ceramics based on K-fluorrichterite (KNaCaMg5Si8O22F2, KFR) have potential for use in restorative dentistry and biomedical applications because they may be cast to shape and, when cerammed, have high biaxial flexural strength and fracture toughness. Excess CaO in canasite-based chain silicate compositions is known to enhance their bioactivity. Therefore, two new glass ceramic compositions have been fabricated with 5 mol% CaF2 (Glass A) and 5 mol% CaO (Glass B) substituted for MgO in the KFR formula unit. The phase evolution of Glasses A and B was studied in detail using X-ray diffraction and transmission electron microscopy. In addition, their mechanical properties were assessed. For Glass A, the fracture toughness (FT=2.66±0.02 MPa·m1/2) and biaxial flexural strength (BFS=227.3±24.5 MPa) were optimized for samples heat treated at 900°C for 4 h. In Glass B, however, the best FT (2.08±0.02 MPa·m1/2) and BFS (217.4±4.4 MPa) were obtained at 950°C. In view of their excellent mechanical properties and castability, Glasses A and B are considered potential candidates for fabrication of custom medical devices in restorative dentistry and moderate load-bearing reconstructive bone surgery. [source] Engineering microporosity in bacterial cellulose scaffoldsJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 6 2008Henrik Bäckdahl Abstract The scaffold is an essential component in tissue engineering. A novel method to prepare three-dimensional (3D) nanofibril network scaffolds with controlled microporosity has been developed. By placing paraffin wax and starch particles of various sizes in a growing culture of Acetobacter xylinum, bacterial cellulose scaffolds of different morphologies and interconnectivity were prepared. Paraffin particles were incorporated throughout the scaffold, while starch particles were found only in the outermost area of the resulting scaffold. The porogens were successfully removed after culture with bacteria and no residues were detected with electron spectroscopy for chemical analysis (ESCA) or Fourier transform infra-red spectroscopy (FT,IR). Resulting scaffolds were seeded with smooth muscle cells (SMCs) and investigated using histology and organ bath techniques. SMC were selected as the cell type since the main purpose of the resulting scaffolds is for tissue engineered blood vessels. SMCs attached to and proliferated on and partly into the scaffolds. Copyright © 2008 John Wiley & Sons, Ltd. [source] Alias-free image reconstruction using Fresnel transform in the phase-scrambling Fourier imaging techniqueMAGNETIC RESONANCE IN MEDICINE, Issue 2 2008Satoshi Ito Abstract An image reconstruction technique that reduces aliasing artifacts by scalable image reconstruction in magnetic resonance imaging (MRI) is proposed. The signal obtained by the phase-scrambling Fourier transform (PSFT) imaging technique can be transformed to the signal described in the Fresnel transform equation of the objects. Therefore, image reconstruction can be performed not only by inverse FT but also by inverse Fresnel transform. When a phase-scrambling coefficient is given in a certain range, image reconstruction by inverse Fresnel transform allows shrinking of images over rather wide scales. Thus, reduced aliasing images can be reconstructed even from signals that produce serious aliasing artifacts by standard inverse FT reconstruction. Simulation and experimental studies reveal that the proposed method can be used to produce reduced aliasing images. Magn Reson Med 60:422,430, 2008. © 2008 Wiley-Liss, Inc. [source] Natural linewidth chemical shift imaging (NL-CSI)MAGNETIC RESONANCE IN MEDICINE, Issue 1 2006Adil Bashir Abstract The discrete Fourier transform (FT) is a conventional method for spatial reconstruction of chemical shifting imaging (CSI) data. Due to point spread function (PSF) effects, FT reconstruction leads to intervoxel signal leakage (Gibbs ringing). Spectral localization by imaging (SLIM) reconstruction was previously proposed to overcome this intervoxel signal contamination. However, the existence of magnetic field inhomogeneities creates an additional source of intervoxel signal leakage. It is demonstrated herein that even small field inhomogeneities substantially amplify intervoxel signal leakage in both FT and SLIM reconstruction approaches. A new CSI data acquisition strategy and reconstruction algorithm (natural linewidth (NL) CSI) is presented that eliminates effects of magnetic field inhomogeneity-induced intervoxel signal leakage and intravoxel phase dispersion on acquired data. The approach is based on acquired CSI data, high-resolution images, and magnetic field maps. The data are reconstructed based on the imaged object structure (as in the SLIM approach) and a reconstruction matrix that takes into account the inhomogeneous field distribution inside anatomically homogeneous compartments. Phantom and in vivo results show that the new method allows field inhomogeneity effects from the acquired MR signal to be removed so that the signal decay is determined only by the "natural" R2 relaxation rate constant (hence the term "natural linewidth" CSI). Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Simultaneous echo refocusing in EPIMAGNETIC RESONANCE IN MEDICINE, Issue 1 2002David A. Feinberg Abstract A method to encode multiple two-dimensional Fourier transform (2D FT) images within a single echo train is presented. This new method, simultaneous echo refocusing (SER), is a departure from prior echo planar image (EPI) sequences which use repeated single-shot echo trains for multislice imaging. SER simultaneously acquires multiple slices in a single-shot echo train utilizing a shared refocusing process. The SER technique acquires data faster than conventional multislice EPI since it uses fewer gradient switchings and fewer preparation pulses such as diffusion gradients. SER introduces a new capability to simultaneously record multiple spatially separated sources of physiologic information in subsecond image acquisitions, which enables several applications that are dependent on temporal coherence in MRI data including velocity vector field mapping and brain activation mapping. Magn Reson Med 48:1,5, 2002. © 2002 Wiley-Liss, Inc. [source] Image-based EPI ghost correction using an algorithm based on projection onto convex sets (POCS)MAGNETIC RESONANCE IN MEDICINE, Issue 4 2002K.J. Lee Abstract This work describes the use of a method, based on the projection onto convex sets (POCS) algorithm, for reduction of the N/2 ghost in echo-planar imaging (EPI). In this method, ghosts outside the parent image are set to zero and a model k -space is obtained from the Fourier transform (FT) of the resulting image. The zeroth- and first-order phase corrections for each line of the original k -space are estimated by comparison with the corresponding line in the model k -space. To overcome problems of phase wrapping, the first-order phase corrections for the lines of the original k -space are estimated by registration with the corresponding lines in the model k -space. It is shown that applying these corrections will result in a reduction of the ghost, and that iterating the process will result in a convergence towards an image in which the ghost is minimized. The method is tested on spin-echo EPI data. The results show that the method is robust and remarkably effective, reducing the N/2 ghost to a level nearly comparable to that achieved with reference scans. Magn Reson Med 47:812,817, 2002. © 2002 Wiley-Liss, Inc. [source] Sensory potentials evoked by tactile stimulation of different indentation velocities at the finger and palmMUSCLE AND NERVE, Issue 9 2001Masayuki Baba MD Abstract Previous studies suggest that the rate of indentation of a tactile probe determines which skin mechanoreceptors are activated. To further investigate this possibility, indentations of 300 ,m at velocities of 100 (T100) and 400 ,m/ms (T400) were applied to the tip (FT) and the proximal phalanx of digit III (PP) and the thenar eminence (Pm) of ten healthy volunteers, and compared with responses after electrical stimulation at the FT. Compound sensory action potentials (CSAPs) were recorded from the median nerve through needle electrodes at the wrist and elbow. The maximal sensory conduction velocities (SNCVs) between wrist and elbow were similar with electrical and T400 stimulation, but on average were 15% lower with T100 stimulation (P < 0.001). With both indentation velocities, SNCVs were similar regardless of stimulation sites. Amplitudes of tactile CSAPs with FT stimulation were 1,2 ,V at T400 and 0.3,0.4 ,V at T100. The CSAP areas evoked by T100 stimulation showed a reduction from fingertip to proximal finger to palm (P < 0.05,0.005), whereas those obtained with T400 stimulation showed a reduction only at the palm (P < 0.05). The results support previous studies indicating that fast indentation at 400 ,m/ms activated deeply placed Pacinian corpuscles as well as superficially situated Meissner corpuscles, whereas slower indentation at 100 ,m/ms activated primarily Meissner corpuscles. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1213,1218, 2001 [source] Changes in the Room-temperature Emission Spectrum of Chlorophyll During Fast and Slow Phases of the Kautsky Effect in Intact Leaves,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Fabrice Franck ABSTRACT Changes in the room-temperature emission spectrum of chlorophyll (Chl) were analyzed using fast diode-array recordings during the Kautsky effect in mature and in greening barley leaves. In mature leaves, the comparison of Fo (basal level of fluorescence yield at transient O) and FM (maximum level of fluorescence yield at transient M) spectra showed that the relative amplitude of total variable fluorescence was maximal for the 684 nm Photosystem II (PSII) band and minimal for the 725 nm Photosystem I band. During the increase from Fo to FM a progressive redshift of the spectrum of variable fluorescence occurred. This shift reflected the different fluorescence rise kinetics of different layers of chloroplasts inside the leaf. This was verified by simulating the effect of screening on the emission spectrum of isolated chloroplasts and by experiments on greening leaves with low Chl content. In addition, experiments performed at different greening stages showed that the presence of uncoupled Chl at early-greening stages and lightharvesting complex II (LHCII) at later stages have detectable but minor effects on the shape of room-temperature emission spectra. When strong actinic light was applied to mature green leaves, the slow fluorescence yield, which declined from FM to FT (steady-state level of fluorescence yield at transient T), was accompanied by a slight redshift of the 684 nm PSII band because of nonphotochemical quenching of short-wavelengthemitting Chl ascribed to LHCII. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||