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Initial Stages (initial + stage)
Selected AbstractsINITIAL STAGES OF REPRODUCTIVE ISOLATION IN TWO SPECIES OF THE ENDANGERED SONORAN TOPMINNOWEVOLUTION, Issue 12 2003Carla R. Hurt Abstract Long-term geographic isolation can result in reproductive incompatibilities due to forces such as mutation, genetic drift, and differential selection. In the Sonoran topminnow, molecular genetic studies of mtDNA, microsatellites, and MHC genes have shown that the endangered Gila and Yaqui topminnows are substantially different, suggesting that divergence took place approximately two million years ago. Here we examined hybrid crosses and backcrosses between these two allopatric taxa to evaluate the accumulation of postmating barriers to reproduction. These results are then compared with results from a previous study where male topminnows were shown to mate assortatively with conspecific females. Despite their preference for conspecific mates, both types of interspecific crosses successfully produced offspring. There was evidence of reduced hybrid fitness, including smaller mean brood size and male-biased sex ratio, for some classes of backcrosses. Brood sizes and interbrood intervals varied significantly when hybrids were subdivided into different cross categories. Our results illustrate the importance of distinctly defining hybrid classes in studies of reproductive isolation. To our knowledge, this is the first such detailed evolutionary analysis in endangered fish taxa. [source] Sentinel Lymph Node Excision and PET-CT in the Initial Stage of Malignant Melanoma: A Retrospective Analysis of 61 Patients with Malignant Melanoma in American Joint Committee on Cancer Stages I and IIDERMATOLOGIC SURGERY, Issue 4 2010JOACHIM KLODE MD BACKGROUND AND OBJECTIVES Sentinel lymph node excision (SLNE) for the detection of regional nodal metastases and staging of malignant melanoma has resulted in some controversies in international discussions. Positron emission tomography with computerized tomography (PET-CT), a noninvasive imaging procedure for the detection of regional nodal metastases, has increasingly become of interest. Our study is a direct comparison of SLNE and PET-CT in patients with early-stage malignant melanoma. MATERIALS AND METHODS We retrospectively analyzed data from 61 patients with primary malignant melanoma with a Breslow index greater than 1.0 mm. RESULTS Metastatic SLNs were found in 14 patients (23%); 17 metastatic lymph nodes were detected overall, only one of which was identified preoperatively using PET-CT. Thus, PET-CT showed a sensitivity of 5.9% and a negative predictive value of 78%. CONCLUSION SLNE is much more sensitive than PET-CT in discovering small lymph node metastases. We consider PET-CT unsuitable for the evaluation of early regional lymphatic tumor dissemination in this patient population and recommend that it be limited to malignant melanomas of American Joint Committee on Cancer stages III and IV. We therefore recommend the routine use of SLNE for tumor staging and stratification for adjuvant therapy of patients with stage I and II malignant melanoma. The authors have indicated no significant interest with commercial supporters. [source] Implementing Quality Improvement Strategies in Brazilian Hospitals: A Model for Guidance of the Initial Stage of ImplementationINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 1 2002T. Diana. Since the early 1990s, Brazilian hospitals have increasingly adopted quality improvement strategies with a view to attending more demanding customers and to the higher performance standards required by the Ministry of Health. However, most efforts have not been successful, partly because hospitals lack adequate methodologies, namely implementation models. This paper presents a two-stage model to help Brazilian hospitals deploy such strategies more effectively. It focusses on the development and pilot-test of the model for the buy-in stage. Distinctive features of the model were found to be critical for results at this stage: 1) An ad hoc structure to manage the changes involved; 2) A performance measurement system to lever and monitor its implementation, while aligning the actions taken with strategy objectives. Other aspects found to be crucial for success were creative application of model elements to the culture of the hospital and to Brazilian contingencies. [source] On the Initial Stages of Electrooxidation of Aqueous Maleic Acid on Bi-Doped PbO2ELECTROANALYSIS, Issue 15 2007Carlos Borras Abstract Oxidation of maleic acid in aqueous solution on bismuth-doped lead oxide has been studied. The effects of hydrodynamic conditions on the oxidation rate have been identified. The number of electrons transferred during the initial stages of oxidation as well as the apparent heterogeneous rate constant was obtained from the combined analysis of rotating ring-disk currents and the decrease of concentration at constant potential, determined from UV-vis measurements. The number of electrons involved during electrochemical oxidation was found to be 12, indicating full mineralization to CO2, and the heterogeneous rate constant for oxidation at 1.6,V was 9.8×105,cm s,1. [source] The Role of Support Networks in the Initial Stages of Integration: The Case of West African Newcomers in the NetherlandsINTERNATIONAL MIGRATION, Issue 2 2010Magali Chelpi-den Hamer This study focuses on the role of support networks in West African migration to the Netherlands. The authors examine the interactions of non-State support groups with West African newcomers and explore the nature, scope and function of support. What type of support networks do respondents rely on, under which circumstances, and for how long? What is the scope of support? Is it to be taken for granted? What alternatives are there for those left out of the loop? The findings suggest that support is mainly punctual, in response to a specific need, and for a limited period of time. It is not to be taken for granted, as support groups have limited capacities, and protect themselves from excessive demands. They play a significant role in providing assistance to migrants, yet this role should not be overestimated. [source] Initial stages of neural regeneration in Helisoma trivolvis are dependent upon PLA2 activityDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2003Matthew S. Geddis Abstract Neuronal regeneration after damage to an axon tract requires the rapid sealing of the injured plasma membrane and the subsequent formation of growth cones that can lead regenerating processes to their appropriate target. Membrane sealing and growth cone formation are Ca2+ -dependent processes, but the signaling pathways activated by Ca2+ to bring about these effects remain poorly understood. An in vitro injury model was employed in which neurites from identified snail neurons (Helisoma trivolvis) were transected with a glass microknife, and the formation of new growth cones from the distal portions of transected neurites was recorded at defined times after transection. This study presents three main results. First, phospholipase A2 (PLA2), a calcium-activated enzyme, is necessary for membrane sealing in vitro. Second, PLA2 activity is also required for the formation of a new growth cone after the membrane has sealed successfully. Thus, PLA2 plays a dual role by affecting both growth cone formation and membrane sealing. Third, the injury-induced activation of PLA2 by Ca2+ controls growth cone formation through the production of leukotrienes, secondary metabolites of PLA2 activity. Taken together, these results suggest that the injury-induced Ca2+ influx acts via PLA2 and leukotriene production to assure growth cone formation. These findings indicate that events that cause an inhibition of PLA2 or lipoxygenases, enzymes that produce leukotrienes, could result in the inability of neurites to regenerate. © 2003 Wiley Periodicals, Inc. J Neurobiol 54: 555,565, 2003 [source] Stage 2 Pressure Ulcer Healing in Nursing HomesJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 7 2008Nancy Bergstrom PhD OBJECTIVES: To identify resident and wound characteristics associated with Stage 2 pressure ulcer (PrU) healing time in nursing home residents. DESIGN: Retrospective cohort study with convenience sampling. SETTING: One hundred two nursing homes participating in the National Pressure Ulcer Long-Term Care Study (NPULS) in the United States. PARTICIPANTS: Seven hundred seventy-four residents aged 21 and older with length of stay of 14 days or longer who had at least one initial Stage 2 (hereafter Stage 2) PrU. MEASUREMENTS: Data collected for each resident over a 12-week period included resident characteristics and PrU characteristics, including area when first reached Stage 2. Data were obtained from medical records and logbooks. RESULTS: There were 1,241 initial Stage 2 PrUs on 774 residents; 563 (45.4%) healed. Median time to heal was 46 days. Initial area was significantly associated with days to heal. Using Kaplan-Meier survival analyses, median days to heal was 33 for small (,1 cm2), 53 days for medium (>1 to ,4 cm2), and 73 days for large (>4 cm2) ulcers. Using Cox proportional hazard regression models to examine effects of multiple variables simultaneously, small and medium ulcers and ulcers on residents with agitation and those who had oral eating problem healed more quickly, whereas ulcers on residents who required extensive assistance with seven to eight activities of daily living (ADLs), who temporarily left the facility for the emergency department (ED) or hospital, or whose PrU was on an extremity healed more slowly. CONCLUSION: PrUs on residents with agitation or with oral eating problems were associated with faster healing time. PrUs located on extremities, on residents who went temporarily to the ED or hospital, and on residents with high ADL disabilities were associated with slower healing time. Interaction between PrU size and place of onset was also associated with healing time. For PrU onset before or after admission to the facility, smaller size was associated with faster healing time. [source] Do early therapeutic alliance, motivation, and stages of change predict therapy change for high-risk, psychopathic violent prisoners?CRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 2 2010Devon L. L. Polaschek Background,Examination of the extent of offenders' engagement in change, and in rehabilitation programmes, is important to understanding success or failure following rehabilitation. In treatment programmes, the alliance between therapist and offender, and the therapy process itself appear central to progress offenders make that may reduce their criminal risk. But research with offenders seldom has measured therapeutic alliance and clinical writing suggests that it is difficult to form an alliance with those not ready to change their behaviour; especially with higher risk and psychopathic offenders. Aims and Methods,This study outlines the course of the therapeutic alliance in an 8-month treatment programme for high-risk, PCL-psychopathic violent prisoners. It examines relationships between early-treatment therapeutic alliance, therapists' global ratings of motivation to change, and initial stage of change on dynamic risk factors. In addition, it investigates which factors best predict who will complete treatment and change behaviourally during treatment. Conclusion,In this challenging, high-needs client group, early-programme stage of change, therapists' perceptions of motivation, therapeutic alliance and psychopathy did not predict how much change prisoners made. Regardless of initial levels, prisoners whose alliance increased the most over the course of treatment made the most change. Copyright © 2010 John Wiley & Sons, Ltd. [source] Nutrient limitations during the biofiltration of methyl isoamyl ketoneENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2005Hyun-Keun Son With biofiltration, both organic and inorganic compounds that are toxic to humans and volatile organic compounds from a variety of industrial and public sector sources have been effectively removed. During the initial stage of the acclimation period, the removal capacity of the biofilter is primarily attributed to the adsorption capacity of the media. The adsorption capacity of different types of biofilter media was studied. MIAK (methyl isoamyl ketone), which is one of the major air pollutants in painting operations, was used as the target air pollutant for the biofiltration experiments. All the materials tested exhibited very poor adsorption capacity for MIAK. The effect of nutrient limitation was also evaluated. A gradual decrease of removal capacity was observed under the nutrient-limited environment. When nutrient was provided to the biofilter, the removal capacity increased from 55 to 93% in 3 days. A nutrient ratio of chemical oxygen demand (COD):N:P = 200:4:1 was sufficient for the removal of volatile organic compounds from the polluted air stream. © 2004 American Institute of Chemical Engineers Environ Prog, 2004 [source] Increasing genomic instability during premalignant neoplastic progression revealed through high resolution array-CGHGENES, CHROMOSOMES AND CANCER, Issue 6 2007Lisa A. Lai Chromosomal instability is regarded as an underlying mechanism of neoplastic progression, integral to the clonal selection and evolution that leads to cancer. We evaluated chromosomal instability in premalignant Barrett's esophagus tissue using high resolution Affymetrix mapping 100K SNP arrays as patients progressed through three molecular stages of disease,CDKN2ALOH only, CDKN2ALOH/TP53LOH, and CDKN2ALOH/TP53LOH with aneuploidy. Within individuals over time, we observed increases in both numbers and sizes of regions of LOH or copy number change. In the earliest CDKN2ALOH only samples, we detected few regions with both copy change and LOH, whereas copy loss and LOH were highly correlated in more advanced samples. These data indicate that genomic instability increases in severity and changes character during neoplastic progression. In addition, distinct patterns of clonal evolution could be discerned within a segment of Barrett's esophagus. Overall, this study illustrates that pre-malignant disease can be associated with extensive instability and clonal dynamics that evolve from an initial stage characterized by small recombination-based alterations to one with larger copy change events likely associated with mitotic instability. © 2007 Wiley-Liss, Inc. [source] Reconstruction of palaeo-burial history and pore fluid pressure in foothill areas: a sensitivity test in the Hammam Zriba (Tunisia) and Koh-i-Maran (Pakistan) ore depositsGEOFLUIDS (ELECTRONIC), Issue 2 2003L. Benchilla Abstract The burial and pore fluid pressure history of fluorite ore deposits is reconstructed: (i) at Hammam Zriba,Djebel Guebli along the eastern margin of the Tunisian Atlas; and (ii) at Koh-i-Maran within the northern part of the Kirthar Range in Pakistan. Both the deposits are hosted by Late Jurassic carbonate reservoirs, unconformably overlain by Late Cretaceous seals. Microthermometric analyses on aqueous and petroleum fluid inclusions with pressure,volume,temperature,composition (PVTX) modeling of hydrocarbon fluid isochores are integrated with kinematics and thermal 2D basin modeling in order to determine the age of mineralization. The results suggest a Cenozoic age for the fluorite mineralization and a dual fluid migration model for both ore deposits. The PVTX modeling indicates that the initial stage of fluorite cementation at Hammam Zriba occurred under fluid pressures of 115 ± 5 bars and at a temperature close to 130°C. At Koh-i-Maran, the F3 geodic fluorite mineralization developed under hydrostatic pressures of 200 ± 10 bars, and at temperatures of 125,130°C. The late increase in temperature recorded in the F3 fluorites can be accounted for by rapid rise of hotter fluids (up to 190°C) along open fractures, resulting from hydraulic fracturing of overpressured sedimentary layers. [source] Non-linear version of stabilized conforming nodal integration for Galerkin mesh-free methodsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2002Jiun-Shyan Chen Abstract A stabilized conforming (SC) nodal integration, which meets the integration constraint in the Galerkin mesh-free approximation, is generalized for non-linear problems. Using a Lagrangian discretization, the integration constraints for SC nodal integration are imposed in the undeformed configuration. This is accomplished by introducing a Lagrangian strain smoothing to the deformation gradient, and by performing a nodal integration in the undeformed configuration. The proposed method is independent to the path dependency of the materials. An assumed strain method is employed to formulate the discrete equilibrium equations, and the smoothed deformation gradient serves as the stabilization mechanism in the nodally integrated variational equation. Eigenvalue analysis demonstrated that the proposed strain smoothing provides a stabilization to the nodally integrated discrete equations. By employing Lagrangian shape functions, the computation of smoothed gradient matrix for deformation gradient is only necessary in the initial stage, and it can be stored and reused in the subsequent load steps. A significant gain in computational efficiency is achieved, as well as enhanced accuracy, in comparison with the mesh-free solution using Gauss integration. The performance of the proposed method is shown to be quite robust in dealing with non-uniform discretization. Copyright © 2002 John Wiley & Sons, Ltd. [source] Modelling of wireless TCP for short-lived flows,INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2005Sangheon Pack Abstract The transmission control protocol (TCP) is one of the most important Internet protocols. It provides reliable transport services between two end-hosts. Since TCP performance affects overall network performance, many studies have been done to model TCP performance in the steady state. However, recent researches have shown that most TCP flows are short-lived. Therefore, it is more meaningful to model TCP performance in relation to the initial stage of short-lived flows. In addition, the next-generation Internet will be an unified all-IP network that includes both wireless and wired networks integrated together. In short, modelling short-lived TCP flows in wireless networks constitutes an important axis of research. In this paper, we propose simple wireless TCP models for short-lived flows that extend the existing analytical model proposed in [IEEE Commun. Lett. 2002; 6(2):85,88]. In terms of wireless TCP, we categorized wireless TCP schemes into three types: end-to-end scheme, split connection scheme, and local retransmission scheme, which is similar to the classification proposed in [IEEE/ACM Trans. Networking 1997; 756,769]. To validate the proposed models, we performed ns-2 simulations. The average differences between the session completion time calculated using the proposed model and the simulation result for three schemes are less than 9, 16, and 7 ms, respectively. Consequently, the proposed model provides a satisfactory means of modelling the TCP performance of short-lived wireless TCP flows. Copyright © 2005 John Wiley & Sons, Ltd. [source] The Effect of Seed Vernalization and Irradiation on Growth and Photosynthesis of Field Bean Plants (Vicia faba L. minor) and on Nitrogenase Activity of Root NodulesJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2000W. Filek The effect of seed vernalization (2,3°C; 36 days) and irradiation intensity during vegetation of field bean upon growth and maximum leaf photosynthesis (Pmax) as well as specific (SNA) and total nitrogenase activity (TNA) of root nodules was investigated. The measurements were performed at the initial stage of pod development of varieties with undetermined (cv. Nadwi,a,ski) and determined (cv. Tibo) growth habit. In comparison with plants in shading, those which grew in full irradiation produced larger leaf area and more dry weight, achieving higher Pmax values. Stimulation of leaf area enlargement and dry weight increase, especially in respect to the dry weight of underground parts had a positive and significant effect upon TNA value. Accumulation of dry weight was higher in vernalized than non-vernalized plants, but only in the case of cv. Nadwi,la,ski, in full irradiation conditions. In the case of plants grown in poorer irradiation conditions TNA values were about 68 % (cv. Nadwi,la,ski) and 54 % (cv. Tibo) lower, due to significant limitation of root nodules. TNA value of vernalized cv. Nadwi,la,ski plants was 66 % higher in comparison with non-vernalized plants. However, the effect was visible only in full irradiation conditions, due to simultaneous greater intensity of root nodules production and higher SNA value. A positive effect of vernalization could also be observed in the decrease of a negative correlation between dry weight of root nodules and SNA in both varieties. Zusammenfassung Der Einfluss der Samenvernalisation (3,3°C; 36 Tage) und der Strahlungsintensität während der Vegetation von Fababohnen hinsichtlich des Wachstums und der maximalen Blattfotosynthese (Pmax) sowie der spezifischen (SNA) und Gesamtnitrogenaseaktivität (TNA) der Wurzelknöllchen wurde untersucht. Die Messungen wurden im ersten Stadium der Hülsenentwicklung an Sorten mit undeterminierten (cv. Nadwi,la,ski) und determinierten (cv. Tibo) Wachstumsstrukturen durchgeführt. Ein Vergleich von Pflanzen unter Beschattung mit Pflanzen unter voller Strahlung zeigte, dass beschattete Pflanzen eine gröiere Blattfläche und höheres Trockengewicht produzierten und damit höhere Pmax -Werte erreichten. Stimulation der Blattflächenvergröierung und der Trockenge wichtszunahme, insbesondere im Hinblick auf die Trockengewichte der unterirdischen Pflanzenteile hatte eine positive und signifikante Auswirkung auf den DNA-Wert. Die Akkumulation von Trockenmasse war in vernalisierten Pflanzen höher als in nicht vernalisierten; dies gilt nur für Sorte Nadwi,la,ski unter dem Einfluss voller Strahlung. Im Fall der Pflanzen, die unter geringer Strahlung wuchsen, waren die TNA-Werte ca. 68 % (cv.Nadwi,la,ski) und 54 % (cv. Tibo) geringer als Folge einer signifikanten Begrenzung des Wurzelknöllchenwachstums. TNA-Werte vernalisierter cv. Nadwi,la,ski-Pflanzen waren um 66 % höher im Vergleich mit nicht vernalisierten Pflanzen. Allerdings zeigte sich diese Wirkung nur unter voller Strahlung als Folge einer vergleichsweise gröieren Intensität der Wurzelknöllchenproduktion und höherer SNA-Werte. Der positive Effekt der Vernalisation konnte ebenfalls beobachtet werden bei einer Abnahme der negativen Korrelation zwischen dem Trockengewicht der Wurzelknöllchen und SNA in beiden Sorten. [source] Epidermal differentiation in embryos of the tuatara Sphenodon punctatus (Reptilia, Sphenodontidae) in comparison with the epidermis of other reptilesJOURNAL OF ANATOMY, Issue 1 2007L. Alibardi Abstract Studying the epidermis in primitive reptiles can provide clues regarding evolution of the epidermis during land adaptation in vertebrates. With this aim, the development of the skin of the relatively primitive reptile Sphenodon punctatus in representative embryonic stages was studied by light and electron microscopy and compared with that of other reptiles previously studied. The dermis organizes into a superficial and deep portion when the epidermis starts to form the first layers. At embryonic stages comparable with those of lizards, only one layer of the inner periderm is formed beneath the outer periderm. This also occurs in lizards and snakes so far studied. The outer and inner periderm form the embryonic epidermis and accumulate thick, coarse filaments (25,30 nm thick) and sparse alpha-keratin filaments as in other reptiles. Beneath the embryonic epidermis an oberhautchen and beta-cells form small horny tips that represent overlapping borders along the margin of beta-cells that overlap other beta-cells (in a tile-like arrangement). The tips resemble those of agamine lizards but at a small scale, forming a lamellate-spinulated pattern as previously described in adult epidermis. The embryonic epidermis matures by the dispersion of coarse filaments among keratin at the end of embryonic development and is shed around hatching. The presence of these matrix organelles in the embryonic epidermis of this primitive reptile further indicates that amniote epidermis acquired interkeratin matrix proteins early for land adaptation. Unlike the condition in lizards and snakes, a shedding complex is not formed in the epidermis of embryonic S. punctatus that is like that of the adult. Therefore, as in chelonians and crocodilians, the epidermis of S. punctatus also represents an initial stage that preceded the evolution of the shedding complex for moulting. [source] Study on the long-term thermal-oxidative aging behavior of polyamide 6JOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Ying Shu Abstract The long-term thermal-oxidative aging behavior of polyamide 6 (PA6) was studied by comparison with the stabilized sample in this work. The variation of mechanical properties of the pure and the stabilized samples of PA6 with aging time at 110°C, 130°C, and 150°C were investigated, respectively. The aging mechanism of PA6 under heat and oxygen was studied in terms of the reduced viscosity, crystallization behavior, dynamic mechanical behavior, and chemical composition through the methods of polarized light microscopy (PLM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), X-ray photoelectron energy spectrum (XPS), and so on. The results indicated that at the initial stage of aging, the molecular crosslinking reaction of PA6 dominated resulting in the increase of the mechanical strength, reduced viscosity, and the glass transition temperature of the sample. And the molecular degradation dominated in the subsequent aging process resulting in the decrease of the melting temperature, the increase of the crystallinity, and the formation of the oxides and peroxides products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Cytoprotection by bcl-2 gene transfer against ischemic liver injuries together with repressed lipid peroxidation and increased ascorbic acid in livers and serumJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2004Shinobu Yanada Abstract The maximum gene exhibition was shown to be achieved at 48 h after transfection with human bcl-2 (hbcl-2) genes built in an SV40 early promoter-based plasmid vector and HVJ-liposome for cultured rat hepatocytes. The similar procedure of hbcl-2 transfection was therefore conducted for livers in rats via the portal vein, and after 48 h followed by post-ischemic reperfusion (I/R) operation for some hepatic lobes. The I/R-induced hepatic injuries were in situ observed as both cell morphological degeneration and cellular DNA strand cleavages around capillary vessels of the ischemic liver lobes as detected by HE stain and TUNEL assay, and were biochemically observed as release of two hepatic marker enzymes AST and ALT into serum. All the I/R-induced injuries examined were appreciably repressed for rats transfected with hbcl-2; hbcl-2 was expressed in hepatocytes around the capillaries of ischemic regions such as the median lobe and the left lobe, but scarcely around those of non-ischemic regions. Thus cytoprotection against I/R-induced injuries may be attributed to the I/R-promoted expression of transferred hbcl-2 genes. The possibility was examined firstly by methylphenylindole method, which showed that I/R-enhanced lipid peroxidation in the reference vector-transfected livers were markedly repressed in the hbcl-2 -transfected livers. Contents of ascorbic acid (Asc) in serum and livers of hbcl-2 -transfected rats were enriched, unexpectedly, versus those of non-transfected rats, and were as abundant as 1.90-fold and 1.95- to 2.60-fold versus those in the pre-ischemic state, respectively. After I/R, an immediate decline in serum Asc occurred in hbcl-2 -transfectants, and was followed by prompt restoration up to the pre-ischemic Asc levels in contrast to the unaltered lower Asc levels in non-transfectants except a transient delayed increase. Hepatic Asc contents were also diminished appreciably at the initial stage after I/R in the ischemic lobes of hbcl-2 -transfectants, which however retained more abundant Asc versus non-transfectants especially at the initial I/R stage when scavenging of the oxidative stress should be most necessary for cytoprotection. The results showed a close correlation between cytoprotection by exogenously transferred hbcl-2 and repressive effects on the lipid peroxidation associated with Asc consumption or redistribution. © 2004 Wiley-Liss, Inc. [source] ACTIVITIES OF ,-GALACTOSIDASE AND ,-L-ARABINOFURANOSIDASE, ETHYLENE BIOSYNTHETIC ENZYMES DURING PEACH RIPENING AND SOFTENINGJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2006CHANG-HAI JIN ABSTRACT A study was conducted to determine changes in firmness, ethylene and ethylene biosynthetic enzymes, and the activities of ,-galactosidase (,-GAL) and ,-L-arabinofuranosidase (,-AF) during peach ripening and softening. The activities of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, ACC oxidase and polygalacturonase increased in parallel with ethylene production and declined in firmness during peach ripening, and they appeared at maximum simultaneously at maturity IV. ,-GAL activity was high in unripe peach fruit and it experienced an overall decline during peach ripening. While ,-AF activity changed placidly at the initial stage (maturity I,III), after that it experienced a rapid increasing stage. The preliminary result indicated that ,-GAL and ,-AF, as well as ethylene biosynthetic enzymes, may be involved in the ripening and softening of peach fruit. [source] Antioxidative Ability, Dioscorin Stability, and the Quality of Yam Chips from Various Yam Species as Affected by Processing MethodJOURNAL OF FOOD SCIENCE, Issue 2 2009Y.-M. Liu ABSTRACT:, The antioxidative ability, stability of storage protein dioscorin, and the quality of fried yam chips from different cultivars of Chinese yams influenced by various processing treatments were investigated. Total phenolic content and DPPH free radical scavenging effect were found to be the highest in Mingchien (MC) and the lowest in Keelung (KL) yam. Following processing, freeze-dried yams of all varieties showed the least decrease in total phenolic compounds and DPPH radical scavenging effect, while boiling caused the greatest decrease in both. Fresh yams of all varieties contained the highest dioscorin contents comparing with their counterparts. Boiling and deep-frying caused severe protein denaturation resulting in loss of dioscorin solubility after purification. Freeze-drying resulted in increase in protein surface hydrophobicity (So); nonetheless, it attained higher total phenol content, antioxidative capacity, and dioscorin stability of yams compared with other processing treatments. The peroxide values of all yam chips increased during the initial stage, then declined with advanced storage. Fracturability of all yam chips gradually decreased, due to the absorption of moisture, with increasing storage time. [source] Current therapeutic approaches in childhood chronic hepatitis B infection: A multicenter studyJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2004BUNYAMIN DIKICI Abstract Background and Aim:, The aim of the present study was to compare the therapeutic efficacy of three different regimens in childhood chronic hepatitis B (CHB) infection. Methods:, A total of 182 children with CHB infection were prospectively allocated to three random groups. Sixty-two patients in the first group received high-dose interferon (IFN)-, 2b (10 MU/m2) thrice/weekly alone for 6 months. In the second (n = 60) and third groups (n = 60), IFN-, was used for 6 months (5 MU/m2) thrice/weekly in combination with lamivudine (LAM) (4 mg/kg, maximum 100 mg/day) for 12 months. Lamivudine was started simultaneously with IFN in the second group, while it was started 2 months prior to IFN injections in the third group. Results:, The initial mean alanine aminotransferase (ALT) values for the first, second and third groups were 109 ± 93 IU/L, 101 ± 64 IU/L and 92 ± 42 IU/L, respectively (P > 0.05). At the end of the therapy, ALT values decreased to 82 ± 111 IU/L, 38 ± 41 IU/L and 29 ± 16 IU/L in groups 1, 2 and 3, respectively. The mean ALT value of the first group was significantly different to the second and third groups (P = 0.046 and P = 0.002, respectively) at the end of the therapy and these differences were found to be sustained after 18 months. However, results in the second and third groups were similar (P > 0.05). There were no significant differences in HBeAg clearance and anti-HBe seroconversion at the initial stage, 12 months and 18 months between the three groups (P > 0.05). Hepatitis B virus (HBV) DNA clearance in the first group was different from the second and third groups, while the second and third groups had similar HBV DNA clearance ratios at 12 and 18 months. No significant difference was found in the complete response (normalization of ALT, clearance of HBV DNA and seroconversion of anti HBe) ratios of all groups (at 12 months: 28.8, 45.5, 35.8% and at 18 months 33.3, 49 and 34% in groups 1, 2 and 3, respectively, P > 0.05). Conclusions:, Although the ALT normalization and HBV DNA clearance ratios of IFN plus LAM combination groups were better than the high-dose IFN-, monotherapy group, no significant difference was found in the complete response ratios of all three groups. [source] A novel inorganic hollow fiber membrane reactor for catalytic dehydrogenation of propaneAICHE JOURNAL, Issue 9 2009Zhentao Wu Abstract A novel inorganic hollow fiber membrane reactor (iHFMR) has been developed and applied to the catalytic dehydrogenation of propane to propene. Alumina hollow fiber substrates, prepared by a phase inversion/sintering method, possess a unique asymmetric structure that can be characterized by a very porous inner surface from which finger-like voids extend across ,80% of the fiber cross-section with the remaining 20% consisting of a denser sponge-like outer layer. In contrast to other existing Pd/Ag composite membranes, where an intermediate ,-Al2O3 layer is often used to bridge the Pd/Ag layer and the substrate, the Pd/Ag composite membrane prepared in this study was achieved by coating the Pd/Ag layer directly onto the outer surface of the asymmetric substrate. After depositing submicron-sized Pt (0.5 wt %)/,-alumina catalysts in the finger-like voids of the substrates, a highly compact multifunctional iHFMR was developed. Propane conversion as high as 42% was achieved at the initial stage of the reaction at 723 K. In addition, the space-time yields of the iHFMR were ,60 times higher than that of a fixed bed reactor, demonstrating advantages of using iHFMR for dehydrogenation reactions. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Precise landmarking in computer assisted total knee arthroplasty is critical to final alignmentJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 10 2010Yaron S. Brin Abstract Image-free computer navigation systems build a frame of reference of a patient's knee from anatomical landmarks entered by the surgeon during the initial stage of total knee arthroplasty. We performed tibial cuts on 70 sawbones using computer navigation. All landmarks were marked identically except for the tibial mechanical entry point, which was marked correctly in 10 bones and with offsets of 5, 10, and 15,mm medially and laterally in the others. The actual coronal angle of the tibial cuts was measured directly and compared to the final angle given by the navigation system. Significant deviations of the coronal angle were observed in the trial groups. Landmarking errors during navigated TKA can lead to inaccurate tibial bone cuts. This navigation system did not have an iterative software method to verify landmarking errors that can lead to inaccurate tibia bone cuts. Published by Wiley Periodicals, Inc. J Orthop Res 28:1355,1359, 2010 [source] Low intensity pulsed ultrasound accelerated bone remodeling during consolidation stage of distraction osteogenesisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2006Chun Wai Chan Abstract Bone regeneration in distraction osteogenesis occurs under tensile stress with axial rhythmic distraction after osteotomy. In this study, we evaluated if the low intensity pulsed ultrasound (LIPUS) was also effective on enhancement of bone remodeling during consolidation stage of distraction osteogenesis. Open osteotomy of seventeen 18-week-old female New Zealand rabbit tibiae were performed. The distraction was applied with the rate of 1 mm per day. LIPUS (30 mW/cm2, 1.5 MHz) was delivered for 20 min per day during 4-week consolidation stage (n,=,10). The animals without treatment served as sham group (n,=,7). Plain X-ray, peripheral quantitative computational tomography (pQCT), and torsional test were performed. Results showed that smaller radiolucent interzone of LIPUS treatment group was gradually occupied by calcified tissue in plain X-ray at week 2. The bone mineral density (BMD) measured on radiographs increased by 9.18% in the LIPUS group. Bone mineral content (BMC), hard callus volume, and bone strength index (BSI) measured by pQCT were 83%, 116%, and 94%, respectively, in LIPUS group that were significantly greater than those of the controls. At the 4th week, LIPUS-treated callus showed the development of neocorticalization in the proximal and distal region. The BMC, hard callus volume, and BSI of LIPUS group decreased and was not significantly different from control. This was also confirmed by the maximum torque of LIPUS-treated callus (1424.2,±,457.3 N,·,mm) obtained at week 4, which did not differ from that of the sham group (1968.8,±,895.1 N,·,mm). In conclusion, the effective period of LIPUS treatment was at the initial stage of consolidation, with accelerated bone formation and remodeling. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] A novel synthetic peptide vector system for optimal gene delivery to bone marrow stromal cellsJOURNAL OF PEPTIDE SCIENCE, Issue 3 2007Pan Haitao Abstract A 23-amino acid, bifunctional, integrin-targeted synthetic peptide was evaluated for ex vivo gene delivery to rabbit bone marrow stromal cells (BMSCs). The peptide (K)16GRGDSPC consists of an amino terminal domain of 16 lysines for electrostatic binding of DNA, and a 7-amino acid integrin-binding domain at the carboxyl terminal. PcDNA3-EGFP plasmids were transfected into BMSCs by (K)16GRGDSPC and the positive cells gave out a bright green fluorescence. High levels of gene delivery of pcDNA3-TGF-,1 plasmids were obtained with 2 to 4 µg/ml DNA concentration, with (K)16GRGDSPC at an optimal peptide: DNA w/w ratio of 3:1, with a required exposure time of more than 4 h but shorter than 24 h for BMSC exposure to the peptide/DNA complexes with completely absent serum in the initial stage; with 100 µM chloroquine and at least 8 h exposure for BMSC exposure to chloroquine; with a fusogenic peptide at an optimal (K)16GRGDSPC/DNA/fusogenic peptide w/w ratio of 3:1:5; and with Lipofectamine 2000 at an optimal (K)16GRGDSPC/DNA/Lipofectamine 2000 w/w ratio of 3:1:2 at a constant DNA concentration of 2 µg/ml. Chloroquine, the fusogenic peptide and Lipofectamine 2000 all significantly promoted gene delivery, but chloroquine was more effective than the fusogenic peptide and had obvious synergistic effects with Lipofectamine 2000. Under optimal conditions, TGF-,1 gene was transfected into BMSCs without observable toxicity, and the stable expression was examined by RT-PCR and Western blot analysis. The stable transgenic cells showed obvious bands. This novel synthetic peptide, providing a new way for the use of polylysine and RGD motif in DNA vector system, is potentially well suited to ex vivo gene delivery to BMSCs for experimental and clinical applications in the field of bone tissue engineering. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd. [source] PHOTOSYNTHETIC INSENSITIVITY OF THE TERRESTRIAL CYANOBACTERIUM NOSTOC FLAGELLIFORME TO SOLAR UV RADIATION WHILE REHYDRATED OR DESICCATED,JOURNAL OF PHYCOLOGY, Issue 4 2007Kunshan Gao Photosynthetic performance of the terrestrial cyanobacterium Nostoc flagelliforme (M. J. Berkeley et M. A. Curtis) Bornet et Flahault during rehydration and desiccation has been previously characterized, but little is known about the effects of solar UV radiation (280,400 nm) on this species. We investigated the photochemical activity during rehydration and subsequent desiccation while exposing the filamentous colonies to different solar radiation treatments. Photochemical activity could be reactivated by rehydration under full-spectrum solar radiation, the species being insensitive to both ultraviolet-A radiation (UVAR; 315,400 nm) and ultraviolet-B radiation (UVBR). When the rehydrated colonies were exposed for desiccation, the effective PSII photochemical yield was inhibited by visible radiation (PAR) at the initial stage of water loss, then increased with further decrease in water content, and reached its highest value at the water content of 10%,30%. However, no significant difference was observed among the radiation treatments except for the moment when they were desiccated to critical water content of about 2%,3%. At such a critical water content, significant reduction by UVBR of the effective quantum yield was observed in the colonies that were previously rehydrated under indoor light [without ultraviolet radiation (UVR)], but not in those reactivated under scattered or direct solar radiation (with UVR), indicating that preexposure to UVR during rehydration led to higher resistance to UVR during desiccation. The photosynthetic CO2 uptake by the desiccated colonies was enhanced by elevation of CO2 but was not affected by both UVAR and UVBR. It increased with enhanced desiccation to reach the maximal values at water content of 40%,50%. The UV-absorbing compounds and the colony sheath were suggested to play an important role in screening harmful UVR. [source] Unusual cationic ring-opening behavior of a novel six-membered ring spiro-orthocarbonate bearing adamantane backbonesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2004Tetsuo Hino Ring-opening reactions of novel six-membered ring spiro-orthocarbonate bearing adamantane backbones 1 were investigated with several cationic initiators. As a result, the decarboxylative product, polyether 4 along with or without cyclic carbonate 3 were unusually formed instead of the anticipated poly(ether-carbonate) 2. The present unexpected reaction behavior can be explained to proceed via predominantly decomposition of starting monomer 1 to cyclic carbonate 3 and oxetane derivative 11 at the initial stage. [source] Ultraviolet curing of acrylic systems: Real-time Fourier transform infrared, mechanical, and fluorescence studiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2002Carmen Peinado Abstract The photopolymerization of acrylic-based adhesives has been studied by Fourier transform infrared and fluorescence analysis in real time. Real-time infrared spectroscopy reveals the influence of the nature of the photoinitiator on the kinetics of the reaction. Furthermore, the incident light intensity dependence of the polymerization rate shows that primary radical termination is the predominant mechanism during the initial stages of the curing of the acrylic system with bis(2,4,6-trimethylbenzoyl) phenyl phosphine oxide (TMBAPO) as a photoinitiator. The fluorescence intensity of selected probes increases during the ultraviolet curing of the adhesive, sensing microenvironmental viscosity changes. Depending on the nature of the photoinitiator, different fluorescence,conversion curves are observed. For TMBAPO, the fluorescence increases more slowly during the initial stage because of the delay in the gel effect induced by primary radical termination. Mechanical tests have been carried out to determine the shear modulus over the course of the acrylic adhesive ultraviolet curing. In an attempt to extend the applications of the fluorescence probe method, we have undertaken comparisons between the fluorescence changes and shear modulus. Similar features in both curves confirm the feasibility of the fluorescence method for providing information about microstructural changes during network formation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4236,4244, 2002 [source] Suggestive Linkage on Chromosome 1 for a Quantitative Alcohol-Related PhenotypeALCOHOLISM, Issue 10 2002Danielle M. Dick Background Alcohol dependence is a clinically and etiologically heterogeneous disorder. Accordingly, a variety of subtypes of alcohol-dependent individuals have been proposed, and multiple operational definitions of alcohol use, abuse, and dependence have been used in linkage analyses directed toward detecting genes involved in alcohol use and problems. Here, we develop quantitative phenotypes that characterize drinking patterns among both alcoholic and nonalcoholic subjects, and use these phenotypes in subsequent linkage analyses. Methods More than 9000 individuals from alcoholic and control families were administered a semistructured interview and personality questionnaire as part of the initial stage of the Collaborative Study on the Genetics of Alcoholism (COGA). A principal component analysis was conducted on items that captured many of the dimensions of drinking and related behaviors, including aspects of alcohol use, antisocial behavior and affective disturbance when drinking, and personality. Factor scores were computed for all individuals. Nonparametric linkage analyses were conducted on these factor scores, in the initial COGA sample consisting of 987 individuals from 105 extended families, and in a replication sample consisting of 1295 individuals from 157 extended families. Results Three factors were identified, accounting for 68% of the total variance. The most promising regions of linkage appeared for factor 2, on which higher scores indicate a later age of onset of regular drinking and higher harm avoidance. Chromosome 1 yielded consistent evidence of linkage in both samples, with a maximum lod score of 3.3 when the samples were combined for analysis. Consistent suggestion of linkage also was found to chromosome 15. Conclusions Developing novel phenotypes that more accurately model the effect of influential genes may help efforts to detect genes involved in complex disorders. Applying principal component analysis in the COGA sample provided support for some regions of linkage previously reported in COGA, and identified other new, promising regions of linkage. [source] The High-Temperature Oxidation Behavior of Reaction-Bonded Porous Silicon Carbide Ceramics in Dry OxygenJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2010Chuanwei Zheng The oxidation behavior of reaction-bonded porous silicon carbide (RPSC) ceramics in dry oxygen between 1100° and 1500°C was investigated based on four specimens with different porosities. RPSC ceramics exhibited a rapid mass increase in the initial stage of oxidation but a slow mass increase in the following oxidation, which was considerably different from the oxidation behavior of dense SiC. The oxidation kinetics for RPSC can be better represented by an asymptotic law rather than the parabolic law for dense SiC. We suppose that, although oxidation occurred in the entire pore channels at the beginning, the pores were rapidly blocked by the oxide as their growth rate near the pore mouth was very fast due to sufficient oxygen. As the result, the oxidation of the pore interior was stopped in the absence of further oxygen supply. [source] Mechano-Synthesis of Lead,Magnesium,Niobate CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2006Danjela Kuscer The synthesis of Pb(Mg1/3Nb2/3)O3 (PMN) with high-energy milling was studied by X-ray powder diffraction (XRD) using the Rietveld-refinement method. The results are discussed in terms of the qualitative and quantitative composition of the crystalline and amorphous phases as a function of milling time. The mechano-synthesis of PbO, Nb2O5, and MgO leads to the formation of perovskite PMN. In the initial stage of milling, particle size reduction and a high degree of amorphization were observed, together with the simultaneous formation of perovskite and pyrochlore-type structures. A mechanism for the formation of PMN by the mechano-synthesis route is proposed. [source] | ||||||||||||||||||||||||||||||||||||||||||||||