Distribution by Scientific Domains
Distribution within Life Sciences

Terms modified by BT

  • bt cotton
  • bt crop
  • bt maize
  • bt protein
  • bt toxin

  • Selected Abstracts

    A review of empirically supported psychological therapies for mood disorders in adults

    Steven D. Hollon Ph.D.
    Abstract Background: The mood disorders are prevalent and problematic. We review randomized controlled psychotherapy trials to find those that are empirically supported with respect to acute symptom reduction and the prevention of subsequent relapse and recurrence. Methods: We searched the PsycINFO and PubMed databases and the reference sections of chapters and journal articles to identify appropriate articles. Results: One hundred twenty-five studies were found evaluating treatment efficacy for the various mood disorders. With respect to the treatment of major depressive disorder (MDD), interpersonal psychotherapy (IPT), cognitive behavior therapy (CBT), and behavior therapy (BT) are efficacious and specific and brief dynamic therapy (BDT) and emotion-focused therapy (EFT) are possibly efficacious. CBT is efficacious and specific, mindfulness-based cognitive therapy (MBCT) efficacious, and BDT and EFT possibly efficacious in the prevention of relapse/recurrence following treatment termination and IPT and CBT are each possibly efficacious in the prevention of relapse/recurrence if continued or maintained. IPT is possibly efficacious in the treatment of dysthymic disorder. With respect to bipolar disorder (BD), CBT and family-focused therapy (FFT) are efficacious and interpersonal social rhythm therapy (IPSRT) possibly efficacious as adjuncts to medication in the treatment of depression. Psychoeducation (PE) is efficacious in the prevention of mania/hypomania (and possibly depression) and FFT is efficacious and IPSRT and CBT possibly efficacious in preventing bipolar episodes. Conclusions: The newer psychological interventions are as efficacious as and more enduring than medications in the treatment of MDD and may enhance the efficacy of medications in the treatment of BD. Depression and Anxiety, 2010. 2010 Wiley-Liss, Inc. [source]

    The role of the inflammatory markers ferritin, transferrin and fibrinogen in the relationship between major depression and cardiovascular disorders , The German Health Interview and Examination Survey

    B. T. Baune
    Baune BT, Neuhauser H, Ellert U, Berger K. The role of the inflammatory markers ferritin, transferrin and fibrinogen in the relationship between major depression and cardiovascular disorders , The German Health Interview and Examination Survey. Objective:, To determine levels of inflammation (ferritin, transferrin and fibrinogen) in major depression (MDD) and comorbid cardiovascular disease (CVD) in an adult population. Method:, In 4181 participants of the German Health Interview and Examination Survey MDD was assessed through the Composite International Diagnostic Interview (CIDI). Coronary heart disease, stroke, and hypertension were diagnosed by a computer-assisted physician interview. Analyses were performed using anova models stratified for gender. Results:, Ferritin, transferrin and fibrinogen levels showed opposing patterns in individuals with either CVD or MDD alone. In comorbidity analyses, male participants with MDD plus comorbid CHD or hypertension had lower levels of ferritin and lower fibrinogen levels in hypertension compared to men without MDD, while in women, results were inconsistent. Conclusion:, Opposing patterns of inflammatory markers in CVD or MDD alone were reversed when both conditions were present. MDD reduced levels of ferritin, transferrin and fibrinogen in CVD in a gender-specific way. [source]

    Utility of fine-needle aspiration cytology in the classification of leprosy

    I. Satish Rao M.D.
    Abstract The role of fine-needle aspiration cytology (FNAC) in the diagnosis of benign skin lesions has been restricted primarily to the evaluation of bacteriologic and morphologic indices in leprosy. This study was undertaken to evaluate the efficacy of FNAC in the diagnosis and classification of lepromatous lesions. Aspirates of 94 newly diagnosed cases of leprosy were studied, and the bacterial load was determined by modified Ziehl-Neelsen (ZN) stain. A skin biopsy was taken from the same site at the same sitting. Frozen and paraffin sections stained with hematoxylin-eosin (H&E) and ZN stains were examined from the biopsy specimen. In 61 of 94 cases (64.9%), the aspirates were satisfactory. Both diagnosis and classification of leprosy were possible in 40 of these 61 cases; the rest of the aspirates showed nonspecific chronic inflammation. The 39 cases of leprosy where a biopsy was available from the same site were classified on FNAC into tuberculoid (TT and BT), lepromatous (LL and BL), and midborderline (BB) subtypes. Taking the histologic diagnosis and Ridley-Jopling classification to be the gold standard, a strong concordance in tuberculoid leprosy cases (18 of 20 cases, 90%) and in lepromatous cases (15 of 16 cases, 93.7%) was observed. Midborderline cases of leprosy posed a problem, and a correct cytohistological correlation was observed in only one of the three cases. Diagn. Cytopathol. 24:317,321, 2001. 2001 Wiley-Liss, Inc. [source]

    Combined treatment of achalasia , botulinum toxin injection followed by pneumatic dilatation: long-term results

    R. Kroupa
    SUMMARY Injection of botulinum toxin (BT) and pneumatic dilatation are available methods in nonsurgical treatment of achalasia. Authors anticipate beneficial effect of prior BT injection on the success of pneumatic dilatation and duration of its effect. There are no long-term data available to assess efficacy of combined treatment. From 1998 to 2007, 51 consecutive patients (20 men and 31 women, age 24,83) with achalasia were included and prospectively followed up. Each patient received injection of 200 IU of BT into the lower esophageal sphincter (LES) during endoscopy and 8 days later pneumatic dilatation (PD) under X-ray control was performed. The follow-up was established every 3 months first year and then annually. The efficacy was evaluated by a questionnaire concerning patient's symptoms and manometry. Results were compared with 40 historical controls (16 men and 24 women, age 26,80) treated by PD alone using the same method and follow-up. Fifty-one patients underwent combined treatment. Four patients failed in follow-up and were not included for analysis. The mean duration of follow-up was 48 months with range 12,96 months. Thirty-four of forty-seven (72%) patients were satisfied with results with none or very rare and mild troubles at the time of the last visit. Forty-one patients were followed up more than 2 years. Effect of therapy lasted in 75% (31/41) of them. In 17 patients, more than 5 years after treatment, effect lasted in 12 (70%). Mean tonus of LES before therapy was 29 mm Hg (10,80), 3 months after therapy decreased to 14 mmHg (5,26). The cumulative 5 years remission rate (95% CI) in combined treated patients 69% 8% was higher than in controls 50% 9%; however it, was not statistically significant (P= 0.07). In control group 1, case of perforation (2.5%) occurred. Eight patients (17%) with relapse of dysphagia were referred to laparoscopic Heller myotomy with no surgical complication. The main adverse effect was heartburn that appeared in 17 patients (36%). Initial injection of BT followed by PD seems to be effective for long-term results with fewer complications. But the combined therapy is not significantly superior to PD alone. [source]

    Randomized controlled trial of intrasphincteric botulinum toxin A injection versus balloon dilatation in treatment of achalasia cardia

    U. C. Ghoshal
    As the few randomized controlled trials available in the literature comparing botulinum toxin (BT) injection with established endoscopic treatment of achalasia cardia, i.e. pneumatic dilatation, showed conflicting results, we conducted a prospective randomized trial. Seventeen consecutive patients with achalasia cardia diagnosed during a period between December 1997 and February 2000 were randomized into two treatment groups [pneumatic dilatation by Rigiflex dilator (n=10), BT injection by sclerotherapy needle into four quadrants of lower esophageal sphincter (LES) (n=7) 80 units in five cases, 60 units in two cases] after dysphagia grading, endoscopy, barium esophagogram, and manometry, all of which were repeated 1 week after treatment. Patients were followed up clinically for 35.2 14 weeks. Chi-squares, Wilcoxon rank-sum test, Kaplan,Meier method and log-rank tests were used for statistical analysis. After 1 week, 6/7 (86%) BT-treated vs. 8/10 (80%) dilatation-treated patients improved (P=NS). There was no difference in LES pressure and maximum esophageal diameter in the barium esophagogram in the two groups before therapy. Both therapies resulted in significant reduction in LES pressure. The cumulative dysphagia-free state using the Kaplan,Meier method decreased progressively in BT-treated compared with dilatation-treated patients (P=0.027). Two patients with tortuous megaesophagus, one of whom had failed dilatation complicated by perforation previously, improved after BT. One other patient in whom pneumatic dilatation had previously failed improved in a similar manner. BT is as good as pneumatic dilatation in achieving an initial improvement in dysphagia of achalasia cardia. It is also effective in patients with tortuous megaesophagus and previous failed pneumatic dilatation. However, dysphagia often recurs during 1-year follow up. [source]

    Butyltin accumulation in two marine bivalves along a pollution gradient,

    Chuan-Ho Tang
    Abstract In the present study, we describe a field survey regarding the effect of ambient water conditions in the accumulation of tributyltin (TBT) and its metabolites in green mussels (Perna viridis) and Pacific oysters (Crassostrea gigas). The results showed that following the changes in TBT pollution levels, the accumulation of butyltins exhibited clear differences between oysters and mussels. The ratio of TBT to total butyltin (TBT:,BT) decreased from 0.87 to 0.31 with increasing TBT burdens in the oysters. This status suggests that following the increases of TBT burdens, the metabolic rates of TBT were clearly enhanced in oysters; however, this phenomenon was not shown in mussels. The TBT:,BT remained relatively constant at approximately 0.7 in the mussels despite the TBT burdens. Because of this phenomenon, the opposite status of different TBT burdens between oysters and mussels were present at different TBT pollution levels. These observations may provide valuable insight when evaluating or comparing TBT pollution in the environment using oysters and/or mussels as bioindicators. [source]

    Electromyographic evaluation of cervical dystonia for planning of botulinum toxin therapy

    D. Dressler
    The success of botulinum toxin (BT) injections for treatment of cervical dystonia depends on precise identification of dystonic muscles and on quantification of their dystonic involvement. Conventionally, this is attempted by clinical examination analysing the dystonic head position. In this presentation, a more systematic approach is sought by using an electromyography (EMG)-based evaluation procedure. In 10 consecutive patients with cervical dystonia not previously exposed to BT clinical examination, analysing the dystonic head position was performed to classify patients into four groups with similar dystonic head positions. Additionally, a 2-channel concentric needle EMG was used to measure the amplitudes of dystonic and maximal voluntary activities in sternocleidomastoid (SCM), splenius capitis (SC) and trapezius/semispinalis capitis (T/SS) muscles bilaterally. The ratio between both amplitudes, the dystonia ratio, was used to quantify dystonic muscle involvement. In all patients dystonia ratios could be calculated. In patients with similar head positions, EMG evaluation revealed different qualitative and quantitative dystonic involvement patterns. In six patients, there were discrepancies in identification of dystonic muscles between clinical examination and EMG evaluation. EMG evaluation excluded dystonic involvement in five patients. All excluded muscles were SCM. In one of these patients, additional T/SS involvement was detected by EMG evaluation. In one patient, SC involvement was revealed by EMG evaluation. All dystonic muscle involvement detected by EMG evaluation represented genuine dystonic muscle coactivation rather than compensatory muscle activity. The EMG evaluation presented allows quantitative and qualitative identification of dystonic muscle involvement which cannot be achieved by clinical examination. Both pieces of information may be helpful for optimization of BT therapy. [source]

    Conjugated Polymer Based on Polycyclic Aromatics for Bulk Heterojunction Organic Solar Cells: A Case Study of Quadrathienonaphthalene Polymers with 2% Efficiency

    Shengqiang Xiao
    Abstract Polycyclic aromatics offer great flexibility in tuning the energy levels and bandgaps of resulting conjugated polymers. These features have been exploited in the recent examples of benzo[2,1- b:3,4- b']dithiophene (BDT)-based polymers for bulk heterojunction (BHJ) photovoltaics (ACS Appl. Mater. Interfaces2009, 1, 1613). Taking one step further, a simple oxidative photocyclization is used here to convert the BDT with two pendent thiophene units into an enlarged planar polycyclic aromatic ring,quadrathienonaphthalene (QTN). The reduced steric hindrance and more planar structure promotes the intermolecular interaction of QTN- based polymers, leading to increased hole mobility in related polymers. As-synthesized homopolymer (HMPQTN) and donor,acceptor polymer (PQTN - BT) maintain a low highest occupied molecular orbital (HOMO) energy level, ascribable to the polycyclic aromatic (QTN) moiety, which leads to a good open-circuit voltage in BHJ devices of these polymers blended with PCBM ([6,6]-phenyl-C61 -butyric acid methyl ester; HMPQTN: 0.76,V, PQTN - BT: 0.72,V). The donor,acceptor polymer (PQTN - BT) has a smaller optical bandgap (1.6,eV) than that of HMPQTN (2.0,eV), which explains its current (5.69,mA,cm,2) being slightly higher than that of HMPQTN (5.02,mA,cm,2). Overall efficiencies over 2% are achieved for BHJ devices fabricated from either polymer with PCBM as the acceptor. [source]

    Electrophosphorescent Polyfluorenes Containing Osmium Complexes in the Conjugated Backbone,

    Chen-Han Chien
    Abstract Electrophosphorescent copolymers have been synthesized by covalent bonding of a red-emitting osmium complex Os(bpftz), which contains two 3-trifluoromethyl-5-(4- tert -butyl-2-pyridyl)triazolate (bpftz) cyclometalated ligands, into the backbone of a bipolar polyfluorene (PF) copolymer. Employing these copolymers, a highly efficient red polymer light-emitting diode has been realised that has an external quantum efficiency of 18.0%, a maximum brightness of 38,000,cd,m,2, and an emission centered at 618,nm. In addition, after incorporating appropriate amounts of green-emitting benzothiadiazole (BT) and the aforementioned Os(bpftz) into the bipolar PF, an efficient white-light electroluminescent polymer is obtained that displays simultaneous blue, green, and red emissions. [source]

    Generation of Compositional-Gradient Structures in Biodegradable, Immiscible, Polymer Blends by Intermolecular Hydrogen-Bonding Interactions,

    B. Hexig
    Abstract A biodegradable, immiscible poly(butylenes adipate- co -butylenes terephthalate) [P(BA- co -BT)]/poly(ethylene oxide) (PEO) polymer blend film with compositional gradient in the film-thickness direction has been successfully prepared in the presence of a low-molecular-weight compound 4,4,-thiodiphenal (TDP), which is used as a miscibility-enhancing agent. The miscibilities of the P(BA- co -BT)/PEO/TDP ternary blend films and the P(BA- co -BT)/PEO/TDP gradient film were investigated by differential scanning calorimetry (DSC). The compositional gradient structure of the P(BA- co -BT)/PEO/TDP (46/46/8 w/w/w) film has been confirmed by microscopic mapping measurement of Fourier-transform infrared spectra and dynamic mechanical thermal analysis. We have developed a new strategy for generating gradient-phase structures in immiscible polymer-blend systems by homogenization, i.e., adding a third agent that can enhance the miscibility of the two immiscible polymers through simultaneous formation of hydrogen bonds with two component polymers. [source]

    The anatomic location of pancreatic cancer is a prognostic factor for survival

    HPB, Issue 5 2008
    Avo Artinyan
    Abstract Background. Pancreatic cancers of the body and tail (BT) appear to have poorer survival compared with head (HD) lesions. We hypothesized that potential disparities in outcome may be related to tumor location. Our objective was to examine the relationship between tumor location and survival. Methods. The Surveillance, Epidemiology, and End Results registry identified 33,752 patients with pancreatic adenocarcinoma and 6443 patients who underwent cancer-directed surgery between 1988 and 2004. Differences in survival and relationships between tumor location and clinical factors were assessed. Multivariate analysis was performed to determine the prognostic significance of tumor location. Results. Median survival for the entire cohort was five months and was significantly lower for BT compared to HD lesions (four vs. six months, p<0.001). Distant metastases (67% vs. 36%, p<0.001) were greater and cancer-directed surgery (16% vs. 30%, p<0.001) was lower for BT tumors. Of 6443 resected patients, HD patients (n=5118) were younger, had a greater number of harvested lymph nodes, were more likely to be lymph node-positive, and had a higher proportion of T3/T4 lesions. Significant univariate predictors of survival included age, T-stage, number of positive and harvested lymph nodes. On multivariate analysis, BT location was a significant prognostic factor for decreased survival (OR 1.11, 95% CI 1.00,1.23, p=0.05). Discussion. Pancreatic BT cancers have a lower rate of resectability and poorer overall survival compared to HD lesions. Prospective large-cohort studies may definitively prove that tumor location is a prognostic factor for survival in patients with pancreatic cancer. [source]

    Dental hygiene students' part-time jobs in dental practices in the Netherlands

    JHG Poorterman
    To cite this article: Int J Dent Hygiene DOI: 10.1111/j.1601-5037.2009.00415.x Poorterman JHG, Dikkes BT, Brand HS. Dental hygiene students' part-time jobs in dental practices in the Netherlands. Abstract:, Objective:, Many students have paid employment while studying. In the Netherlands, the Individual Health Care Professions Act (IHCP Act) allows dental hygiene students to work under certain conditions in a dental practice. The aim of the study was to determine how many dental hygiene students have part-time job employment in dental practice and which professional tasks they carry out. We also asked the dental hygiene students their opinion of the IHCP Act. Methods:, All the enrolled dental hygiene students (n = 341) at a School of Health in the Netherlands received a questionnaire by email. Results:, The response was 52% (176 students). Of the responding students, 75% had paid employment in addition to their study. A proportion of the students (35%) worked in a dental practice. The median number of hours worked per week was eight. Study year, age and prior education were positively related to working part-time in dental practice. Activities frequently performed were giving oral hygiene instruction, fluoride applications, scaling and root planning, providing chair side assistance and giving local anaesthesia. Although the self-reported knowledge about the IHCP Act was high, almost half of the students expressed the need for more detailed legal information. Conclusions:, Many dental hygiene students work in a dental practice, taking over a number of tasks usually performed by the dentist. More information in the dental hygiene curriculum about the requirements of the IHCP Act seems desirable. [source]

    Role of exposure with response prevention in cognitive,behavioral therapy for bulimia nervosa: Three-year follow-up results

    Frances A. Carter
    Abstract Background Previous studies have not reported the longer-term outcome of exposure-based treatments for bulimia nervosa. The current study evaluated the 3-year outcome of a randomized clinical trial that compared the additive efficacy of exposure-based versus nonexposure-based behavioral treatments (BT) with a core of cognitive,behavior therapy (CBT). Methods One hundred thirteen women participated in the original treatment trial and attended a 3-year follow-up assessment. Eating disorder diagnoses and primary, secondary, and tertiary outcome measures were assessed. The impact of treatment completion on symptomatology and the stability of treatment effects over time were evaluated. Results At the 3-year follow-up, 85% of the sample had no current diagnosis of bulimia nervosa and 69% had no current eating disorder diagnoses of any sort. Failure to complete CBT was associated with inferior outcome. No clear advantages were evident for participants who completed BT in addition to CBT. For subjects who did complete both CBT and BT, outcome was mostly stable from posttreatment to follow-up. No differential effects were found for exposure versus nonexposure-based treatments at 3-year follow-up. Discussion The results of the current study compare favorably with other treatment outcome studies for bulimia nervosa and suggest that treatment gains are maintained after 3 years. 2003 by Wiley Periodicals, Inc. Int J Eat Disord 33: 127,135, 2003. [source]

    Production of zero trans Iranian vanaspati using chemical transesterification and blending techniques from palm olein, rapeseed and sunflower oils

    Jamshid Farmani
    Summary Chemical transesterification and blending techniques were used for producing zero trans fats suitable for use as Iranian vanaspati. Triple blends of palm olein (POo), rapeseed (RSO) and sunflower oil (SFO) were subjected to two different treatments: (i) blending and then transesterification (BT) and (ii) transesterification of pure POo before blending with RSO and SFO (TB). The changes in slip melting point (SMP), solid fat content (SFC), carbon number (CN) triacylglycerol (TAG) composition, induction period (IP) of oxidation at 120 C and IP of crystallisation at 20 C of blends before and after treatments were investigated. Both BT and TB methods resulted in an increase in the CN48 TAG molecules, SMP and SFC, and a decrease in the IP of oxidation and crystallisation of initial blends. Samples made by TB method had higher CN48 TAG content, SMP, SFC and IP of oxidation, and lower IP of crystallisation than those made by BT method. Correlation between SFC at 20 C and saturated fatty acid (SFA) content of the treated blends indicated that the SFA must be higher than 33.1% and 26.8% for BT and TB methods, respectively, to obtain fats suitable for use as vanaspati. [source]

    Measurement-specific bioavailable testosterone using concanavalin A precipitation: Comparison of calculated and assayed bioavailable testosterone

    Kenrou Yamamoto
    Objective: To assess the value of calculated bioavailable testosterone (cBT) and assayed BT (aBT) for the diagnosis of late-onset hypogonadism (LOH) in middle-aged and elderly subjects. Methods: In order to assay serum BT, sex hormone-binding globulin was precipitated with concanavalin-A and then testosterone was measured using liquid chromatography-tandem mass spectrometry. To validate the non-sex-hormone-binding-globulin-bound testosterone, gel filtration chromatography and concanavalin-A sepharose were used. Following this validation, the usefulness between aBT and cBT was evaluated in clinical samples. Results: Eighty-eight healthy male volunteers (mean age 65.6 years, range: 50,86) were recruited for this study. A significant correlation was found between cBT and aBT (R2 = 0.53, P < 0.01). Mean value ratio (cBT/aBT) was 2.48. Both cBT (R2 = 0.122) and aBT (R2 = 0.251) decreased with age. Variations in aBT were less marked than those for cBT, suggesting that aBT can be used to determine age-related reduced testosterone levels. Conclusion: aBT levels are more reliable than cBT levels for the diagnosis of LOH in middle-aged and elderly subjects. [source]

    Selected As the Best Paper in the 1990s: Reducing Frailty and Falls in Older Persons: An Investigation of Tai Chi and Computerized Balance Training

    FAPTA, Steven L. Wolf PhD
    Objectives: To evaluate the effects of two exercise approaches, tai chi (TC) and computerized balance training (BT), on specified primary outcomes (biomedical, functional, and psychosocial indicators of frailty) and secondary outcomes (occurrences of fall). Design: The Atlanta Frailty and Injuries: Cooperative Studies and Intervention Techniques, a prospective, randomized, controlled clinical trial with three arms (TC, BT, and education (ED)). Intervention length was 15 weeks, with primary outcomes measured before and after intervention and at 4-month follow-up. Falls were monitored continuously throughout the study. Setting: Persons aged 70 and older living in the community. Participants: A total of 200 participants, 162 women and 38 men; mean age was 76.2. Measurements: Biomedical (strength, flexibility, cardiovascular endurance, body composition), functional instrumental activities of daily living (IADL), and psychosocial well-being (Center for Epidemiological Studies for Depression scale, fear of falling questionnaire, self-perception of present and future health, mastery index, perceived quality of sleep, and intrusiveness) variables. Results: Grip strength declined in all groups, and lower extremity range of motion showed limited but statistically significant changes. Lowered blood pressure before and after a 12-minute walk was seen following TC participation. Fear of falling responses and intrusiveness responses were reduced after the TC intervention compared with the ED group (P=.046 and P=.058, respectively). After adjusting for fall risk factors, TC was found to reduce the risk of multiple falls by 47.5%. Conclusion: A moderate TC intervention can impact favorably on defined biomedical and psychosocial indices of frailty. This intervention can also have favorable effects upon the occurrence of falls. TC warrants further study as an exercise treatment to improve the health of older people. [source]

    Isolation and characterization of a bacterial strain of the genus Ochrobactrum with methyl parathion mineralizing activity

    X.-H. Qiu
    Abstract Aims:, To isolate and characterize a methyl parathion (MP)-mineralizing bacterium, and to elucidate the degradative pathway of MP and localize the responsible degrading genes. Methods and Results:, A bacterial strain, designated B2, capable of mineralizing MP was isolated from the MP-polluted soil. Analysis of the 16S rRNA gene sequence and phenotypic analysis suggested that strain B2 had a close relationship with Ochrobactrum anthropi. B2 could totally degrade MP and four metabolites [p -nitrophenol (PNP), 4-nitrocatechol (4-NC), 1,2,4-benzenetriol (BT) and hydroquinone (HQ)] were identified by HPLC and gas chromatography-mass spectrometry analyses. Plasmid curing of strain B2 resulted in the loss of ability of B2 to degrade PNP, but not the ability to hydrolyse MP. Conclusions:,Ochrobactrum sp. B2 can mineralize MP rapidly via PNP, 4-NC, BT and HQ pathway. B2 harbours a plasmid encoding the ability to degrade PNP, while MP-hydrolysing activity is encoded on the bacterial chromosome. Significance and Impact of the Study:, This new bacterial strain (B2) capable of mineralizing MP will be useful in a pure-culture remediation process of organophosphate pesticides and their metabolites such as nitroaromatics. [source]

    Assessment of bismuth thiols and conventional disinfectants on drinking water biofilms

    F. Codony
    Abstract Aims: Biofilms in water distribution systems represent a far more significant reservoir of micro-organisms than the water phase. Biofilms are (i) resistant to disinfectants, (ii) nuclei for microbial regrowth, (iii) a refuge for pathogens, (iv) accompanied by taste and odour problems, and (v) corrode surfaces. The effects of the current strategies for disinfection of drinking water systems in large buildings (chlorination, copper and silver ionization, and hyper-heating) were compared with a new generation of bismuth thiol (BT) biocides. Methods and Results: Multispecies biofilms were treated with 08 mg l,1 of free chlorine, 400 and 40 ,g l,1 of copper and silver ions, respectively, at 55 and 70C, and bismuth-2,3-dimercaptopropanol (BisBAL). Furthermore, the effect of combined heat and BisBAL on planktonic cell viability was examined in monoculture using Escherichia coli suspensions. Inactivation rates for BisBAL were similar to copper,silver ions, where the effects were slower than for free chlorine or temperature. The BisBAL effect on E. coli monocultures was augmented greatly by increasing temperatures. Conclusions: Like copper,silver ions, BTs show more persistent residual effects than chlorine and hyper-heating in water systems. BT efficiency increased with temperature. Like copper,silver ions, BT action is relatively slow. Significance and Impact of the Study: BT presents a new approach to containing water biofilms. BT action is not as rapid, but is more thorough than chlorine, and less caustic. BTs may also be more efficacious in hot water systems. At sub-minimum inhibition concentration levels, BTs uniquely inhibit bacterial exopolysaccharide, thereby retarding biofilm formation. Thus, the combination of bactericidal and residual effects may prevent slime build-up in hot water systems. [source]

    Thermal and dielectric properties of bismaleimide-triazine resins containing octa(maleimidophenyl)silsesquioxane

    Hongwei Cao
    Abstract Octa(maleimidophenyl)silsesquioxane (OMPS) was synthesized, characterized, and employed to modify the BT resin which composed of 4,4,-bismaleimidodiphenylmethane (BMI) and 2,2,-bis(4-cyanatophenyl)propane (BCE). The curing reaction between OMPS and BT resin was first investigated. It was found that OMPS accelerate the curing reaction of BCE, and the onset temperature of the cyclotrimerization was reduced up to 95.5C (by DSC). As demonstrated by DSC and FTIR, there was no evidence that indicated the coreaction between maleimide and cyanate ester. 2,2,-diallyl bisphenol A (DBA) and diglycidyl ether of bisphenol A (E-51) (Wuxi Resin Factory, Jiangsu Province, China) were also used to enhance the toughness of BT resin, and the formulated BTA (containing DBA) and BTE (containing E-51) resins were obtained. The thermal properties of BT, BTA, and BTE resins incorporated with OMPS were then investigated. The results of DMA and TG showed that the BT, BTA, and BTE resins containing 1 wt % of OMPS exhibit enhanced thermal properties in comparison with their pristine resins respectively, while more contents of OMPS may impair the thermal properties of the polymer matrix, though the effect of OMPS was slight. Finally, the dielectric constant of these hybrid materials were detected, and their dielectric constant were distinctly reduced by the incorporation of OMPS, while overmuch contents of OMPS were disadvantageous for dielectric constant because of the aggregation of OMPS. 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source]

    Oral administration of diphenyl diselenide potentiates hepatotoxicity induced by carbon tetrachloride in rats

    Cristina W. Nogueira
    Abstract Carbon tetrachloride (CCl4) is a model for studying free radical-induced liver injury and screening hepato-protective drugs. Numerous studies have reported the involvement of oxidative stress in CCl4 -induced liver damage and the hepato-protective effects mediated by different antioxidants. The present study examined the effects of diphenyl diselenide, (PhSe)2, on hepatotoxicity induced by CCl4 in rats. To this end, male Wistar rats received (PhSe)2 by oral route at the dosage of 31.2 mg/kg for one or two days. After the second day of treatment, rats received CCl4 orally in a single dose. The liver and kidney were utilized for determination of histopathology, biochemical [aspartate (ALT) and alanine (AST) aminotransferases, alkaline phosphatase (ALP), total bilirrubin (TB) and gamaglutamyl transferase (GGT)] and toxicological parameters [thiobarbituric reactive species (TBARS) levels, catalase activity, ascorbic acid, nonprotein thiols (NPSH) and aminolevulinate dehydratase (, -ALA-D) activity]. Repeated administration of (PhSe)2 caused a marked potentiation of hepatotoxicity induced by CCl4 exposure, as manifested by an increase in biochemical parameters (AST, ALT, ALP, GGT and BT) and severe alteration in histopathology. This study also demonstrated a potentiation of TBARS levels and a consequent depletion of important antioxidant defenses including catalase and ascorbic acid. Pre-treatment with a single dose of (PhSe)2 prevented the effect of strychnine, a substrate for CYPs, abolishing lethality in mice. This result indicates that (PhSe)2 prevented animal death, suggesting an activator action of (PhSe)2 in CYPs. This study clearly indicates that (PhSe)2 potentiated acute hepatic damage induced by CCl4. Copyright 2008 John Wiley & Sons, Ltd. [source]

    Effects of size, competition and altitude on tree growth

    JOURNAL OF ECOLOGY, Issue 5 2007
    Summary 1,Understanding the factors influencing tree growth is central to forest ecology because of the significance of growth to forest structure and biomass. One of the simplest, yet most controversial growth models, proposed by Enquist and colleagues, predicts that stem-diameter growth scales as the one-third power of stem diameter. Recent analyses of large-scale data sets have challenged the generality of this theory and highlighted the influence of resource competition on the scaling of growth with size. 2Here we explore the factors regulating the diameter growth of 3334 trees of mountain beech (Nothofagus solandri var. cliffortioides) growing in natural single-species forests in New Zealand. Maximum-likelihood modelling was used to quantify the influences of tree size, altitude, the basal area of taller neighbours (BL) and the basal area of all neighbours (BT) on growth. Our interpretation of the models assumed that taller neighbours compete for light whereas all neighbours compete for nutrients. 3The regression analyses indicate that competition for light has a strong influence on the growth of small trees, whereas competition for nutrients affects trees of all sizes. These findings are consistent with experimental manipulation studies showing that competition for light and nutrients inhibits the growth of small mountain beech trees, and fertilizer application studies showing that nitrogen limits the growth of large trees. 4Tree growth declined with altitude. The regression analyses suggest that the intensity of light competition also declines with altitude, when trees with similar BT and BL values were compared along the gradient. These results are consistent with observations that trees become stunted and have more open canopies at high altitudes. 5Our study is the first to build the effects of competition and environment into Enquist's model of tree growth. We show that competitive interactions alter the scaling of mean growth rate with size, whereas altitude does not influence the scaling of potential growth rate with size. [source]

    Novel saturated red-emitting poly(p -phenylenevinylene) copolymers with narrow-band-gap units of 2,1,3-benzothiadiazole synthesized by a palladium-catalyzed Stille coupling reaction

    Xianzhen Li
    Abstract Novel poly(p -phenylenevinylene) (PPV) copolymers derived from 1-methoxy-4-octyloxyphenylene (MOP), 2,1,3-benzothiadiazole (BT), and trans -1,2-bis(tributylstannyl)ethylene were first prepared by a palladium-catalyzed Stille coupling reaction. The feed ratios of MOP to BT were 99.5:0.5, 99:1, 95:5, 85:15, 70:30, and 50:50. An efficient energy transfer from the 2-methoxy-5-octyloxy- p -phenylenevinylene segment to the narrow-band-gap units was observed. The poly(2-methoxy-5-octyloxy- p -phenylenevinylene-2,1,3-benzothiadiazolevinylene) copolymers emitted deep red light. The maximum electroluminescence emission of these PPV copolymers occurred at 659,724 nm and was accompanied by gradual redshifting with an increasing BT concentration. The photophysical properties were examined in comparison with those of copolymers based on BT and fluorene or N -alkylcarbazole doped with the same BT concentration in the copolymer main chain. 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2325-2336, 2005 [source]

    Phase Characteristics and Piezoelectric Properties in the Bi0.5Na0.5TiO3,BaTiO3,K0.5Na0.5NbO3 System

    Shan-Tao Zhang
    Lead-free 0.94Bi0.5Na0.5TiO3,(0.06,x)BaTiO3,xK0.5Na0.5NbO3 (x=0,0.06) ceramics were prepared. All these compositions have a structure close to the rhombohedral,tetragonal morphotropic phase boundary (MPB) and good electric properties at room temperature. No significant composition dependence of ferroelectric property can be established, whereas a dependence of piezoelectric properties can be observed, e.g. the piezoelectric coefficient (d33), planar coupling factor (kp), and field-induced strain (S) increase with increasing x when x,0.01 and then tend to decrease. The highest d33, kp, and bipolar strain are 118 pC/N, 0.29, and 0.32%, respectively, in the composition with x=0.01. The results not only indicate that BNT,BT,KNN lead-free piezoceramics can persist in the structure close to MPB in a wide composition range but that they may also be helpful for further investigation on lead-free piezoceramics. [source]

    Preparation and Electrical Properties of an Anodized Al2O3,BaTiO3 Composite Film

    Xianfeng Du
    A highly stable, water-based barium titanate BaTiO3, BT, sol was synthesized using a sol,gel route through a chelate lactate technique. Dried BT precursor powders were measured by thermal gravimetry,differential thermal analysis and X-ray diffraction. It was found that BT powders first converted into barium carbonate BaCO3, Ti complex, and intermediate phase Ba2Ti2O5CO3, and then transformed into perovskite phase BaTiO3. The crystallization temperature was about 550C. The low-voltage etched aluminum foils were covered with BT sol by dip coating, and then annealed at 600C for 30 min in air. After that, the samples were anodized in a 15 wt% aqueous solution of ammonium adipate. The voltage,time variations during anodizing were monitored, and the electrical properties of the anodic oxide film were examined. It was shown that the specific capacitance, the product of specific capacitance and withstanding voltage, and leakage current of samples with a BT coating were about 48.93%, 38.50%, and 167% larger than that without a BT coating, respectively. [source]

    Crystallographic Texture Development in Bismuth Sodium Titanate Prepared by Reactive-Templated Grain Growth Method

    Toshio Kimura
    Bi0.5Na0.5TiO3 (BNT) and 0.94Bi0.5Na0.5TiO30.06BaTiO3 (BNT,BT) bulk ceramics with extensive ,100, texture were prepared by the reactive-templated grain growth method, using platelike Bi4Ti3O12 (BIT) particles as templates for BNT. Calcined compacts were composed of matrix grains with random orientation and ,100,-oriented grains transformed from aligned BIT particles, and the texture developed by the growth of oriented grains during sintering. Ceramics with extensive texture were obtained by using the starting mixture containing the maximum concentration of platelike BIT to form the maximum volume fraction of oriented grains. [source]

    Solubility of Silver and Palladium in BaTiO3

    Shao-Ju Shih
    Silver, palladium, and their alloys are frequently used as electrode materials for BaTiO3 (BT) based dielectrics. However, the electrodes and dielectrics usually are cofired at high temperatures, and silver and palladium can dissolve into the BT during cofiring. In the present study, the solubility of silver and palladium into BT after cofiring was determined. Three measurement techniques were used to determine solubility: chemical analysis, structural analysis, and dielectric analysis. The solubility of the silver in the BT was low, 450 ppm, after cofiring at 1290C for 2 h in air. The diffusion distance of the silver ions into the BT was >5 ,m. The solubility of the palladium in the BT was even lower, 50 ppm at 1290C, and the diffusion distance was ,1 ,m. The solubility of both the silver and the palladium in the BT decreased as the oxygen partial pressure of the sintering atmosphere decreased. These results demonstrated that both silver and palladium solutes act as acceptors for BT. [source]

    Morphotropic Phase Boundary in the Pb(Zn1/3Nb2/3O3)-BaTiO3 -PbTiO3 System

    Weizhong Zhu
    The morphotropic phase boundary (MPB) in the relaxor ferroelectric system Pb(Zn1/3Nb2/3O3)-BaTiO3 -PbTiO3 (PZN-BT-PT) with 15 mol% BT was investigated through dielectric permittivity and high-temperature X-ray diffraction measurements. It was revealed that MPB is a broad composition region extending from 12 to 18 mol% PT, within which the temperatures of the permittivity maximum are close to the ending temperatures for the phase transformation from coexisting rhombohedral and tetragonal phases to cubic phase on heating. When the specimen is cooled, the starting temperatures for the rhombohedral-to-tetragonal phase transition increase with increasing PT content. The large thermal hysteresis observed by X-ray diffraction is caused by the phase transformation between rhombohedral and tetragonal phases. On cooling, the MPB curves toward the PT-rich side, so that ceramics within this composition range undergoe successive phase transitions from cubic to rhombohedral and from rhombohedral to tetragonal phase. The diffuseness of the paraelectric-to-ferroelectric phase transition is remarkably decreased by the addition of PT. The enhanced dielectric permittivity peak values for the MPB compositions are correlated with the reduced lattice distortion and phase coexistence. [source]

    Sintering Characteristics in the BaTiO3,Nb2O5,Co3O4 Ternary System: II, Stability of So-called "Core,Shell" Structure

    Hirokazu Chazono
    The sintering characteristics and the reaction of additives with BaTiO3 (BT) were examined for two materials having Nb-rich composition (Comp.N) and Co-rich composition (Comp.C) to elucidate the relation between the stability of the core,shell microstructure and the Nb/Co ratio in the BT,Nb2O5,Co3O4 system. TEM observation revealed that the concentration gradient of Nb and Co existed in the shell region although Nb and Co macroscopically distributed homogeneously. X-ray diffraction analysis showed that the shell formation preceded the densification and completed at about 1280C for both Comp.N and Comp.C as determined from differential scanning calorimetry. A diffusion couple experiment disclosed that Co had a larger diffusivity than Nb and that the diffusion of Co was suppressed when the sample was codoped with a sufficient amount of Nb. On the basis of these experimental results, new mechanisms of the formation and collapse of core,shell structure in the BT,Nb2O5,Co3O4 system were proposed. [source]

    Apixaban, an oral, direct and highly selective factor Xa inhibitor: in vitro, antithrombotic and antihemostatic studies

    P. C. WONG
    Summary.,Background:,Apixaban is an oral, direct and highly selective factor Xa (FXa) inhibitor in late-stage clinical development for the prevention and treatment of thromboembolic diseases. Objective:,We evaluated the in vitro properties of apixaban and its in vivo activities in rabbit models of thrombosis and hemostasis. Methods:,Studies were conducted in arteriovenous-shunt thrombosis (AVST), venous thrombosis (VT), electrically mediated carotid arterial thrombosis (ECAT) and cuticle bleeding time (BT) models. Results:,In vitro, apixaban is potent and selective, with a Ki of 0.08 nm for human FXa. It exhibited species difference in FXa inhibition [FXa Ki (nm): 0.16, rabbit; 1.3, rat; 1.7, dog] and anticoagulation [EC2 (,m, concentration required to double the prothrombin time): 3.6, human; 2.3, rabbit; 7.9, rat; 6.7, dog]. Apixaban at 10 ,m did not alter human and rabbit platelet aggregation to ADP, ,-thrombin, and collagen. In vivo, the values for antithrombotic ED50 (dose that reduced thrombus weight or increased blood flow by 50% of the control) in AVST, VT and ECAT and the values for BT ED3 (dose that increased BT by 3-fold) were 0.27 0.03, 0.11 0.03, 0.07 0.02 and > 3 mg kg,1 h,1 i.v. for apixaban, 0.05 0.01, 0.05 0.01, 0.27 0.08 and > 3 mg kg,1 h,1 i.v. for the indirect FXa inhibitor fondaparinux, and 0.53 0.04, 0.27 0.01, 0.08 0.01 and 0.70 0.07 mg kg,1 day,1 p.o. for the oral anticoagulant warfarin, respectively. Conclusions:,In summary, apixaban was effective in the prevention of experimental thrombosis at doses that preserve hemostasis in rabbits. [source]

    Recombinant activated factor VII efficacy and safety in a model of bleeding and thrombosis in hypothermic rabbits: a blind study

    Summary.,Background:,Recombinant activated factor VII (rFVIIa) is increasingly used to secure hemostasis in hemorrhagic situations in trauma and surgical patients. Hypothermia is often observed in these clinical settings. Objective:,To study the efficacy and safety of rFVIIa in hypothermia in a rabbit model of bleeding and thrombosis. Methods:,Sixty-nine rabbits were anesthetized, ventilated and monitored for blood pressure, temperature and carotid flow. The Folts model was used: a stenosis (75%) and an injury were carried out on the carotid artery, inducing thrombosis. Blood flow decreased as thrombus size increased until the pressure gradient was such that the thrombus was released and local arterial blood flow was suddenly restored. This is known as a cyclic flow reduction (CFR). After counting baseline CFRs during a 20-min period (P1), rabbits were randomized blindly to one of four groups: normothermic (NT) placebo or rFVIIa (150 ,g kg,1), hypothermic (HT) (34 C) placebo or rFVIIa. Then CFRs were recorded over a second period (P2). At the end of the experiment, a hepato-splenic section was performed and the amount of blood loss was recorded. After each period, the following were measured: ear immersion bleeding time (BT), hemoglobin, platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT) and fibrinogen. Results:,Hypothermia increased BT and blood loss. These effects were reversed by rFVIIa. In NT rabbits, rFVIIa shortened BT but did not reduce blood loss. rFVIIa-treated rabbits bled similarly regardless of temperature. The incidence of CFRs was higher in treated than placebo animals regardless of temperature. rFVIIa decreased PT and aPTT without modifying platelet count or fibrinogen level. Conclusion:,Hemostatic efficacy of rFVIIa was maintained in hypothermia. However, the number of CFRs was higher in the rFVIIa-treated group than in the placebo groups, whether for NT or HT rabbits. [source]