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Study and comparison of polydopamine and its derived carbon decorated nanoparticles in the magnetic solid-phase extraction of estrogens.
Huang, Z, Lee, HK
Journal of chromatography. A. 2015;:41-50
Abstract
Surface functionalization enabled by bioinspired polydopamine (PDA) is recognized as a convenient route for fabrication of multifunctional nanoparticles. In the present work, magnetic nanoparticles with polymer (Fe3O4@PDA) and carbon shell (Fe3O4@C) were prepared by self-oxidation of dopamine, and carbonization of the PDA coating. The performance of the two magnetic sorbents in the extraction and determination of four estrogens, estrone (E1), estradiol (E2), estriol (E3) and diethylstilbestrol (DES) from water samples in the form of magnetic solid-phase extraction was investigated. Orthogonal array design was utilized to facilitate the optimization of the proposed sample preparation approach. The highest extraction capabilities of the two sorbents were achieved under different experimental conditions. Fe3O4@PDA was shown to be superior to Fe3O4@C in the enrichment of estrogens, suggesting stronger interactions were established between the PDA coating and the target compounds. The extraction and desorption operations were enabled more conveniently by magnetic separation and the extracts were analyzed by high-performance liquid chromatography coupled with ultraviolet and fluorescence detection. The limits of detection achieved in the proposed method were in the range of 0.072-0.15ng/mL for E1 and DES, and 0.0017-0.0062ng/mL for E2 and E3. Good precision (>0.9995) was obtained with the linearity ranging from 0.2 to 100ng/mL, and from 0.01 to 5ng/mL. The method developed was assessed by analysis of the estrogens in tap water, drain water and bottled mineral water samples.
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Comparison of bulking agents in the treatment of fecal incontinence: a prospective randomized clinical trial.
Morris, OJ, Smith, S, Draganic, B
Techniques in coloproctology. 2013;(5):517-23
Abstract
BACKGROUND We sought to compare two synthetic injectable bulking agents, with known efficacy (PTQ™: a silicone biomaterial and Durasphere(®): pyrolytic carbon-coated beads), in the form of a randomised clinical trial. METHODS Circumferential injection of either agent was performed under local anesthesia and sedation as a day-case procedure. The primary outcome measure was the Wexner incontinence scale. Secondary measures were the short-form 36 (SF-36) quality of life assessment and manometry (maximum resting and squeeze pressures). Follow-up was at 6 weeks, 6 and 12 months. RESULTS Thirty-five patients were randomised, 17 to PTQ(®) and 18 to Durasphere(®). Early closure of the trial occurred, due to the removal of the agent PTQ(®), from the Australian Pharmaceutical Benefits scheme. Wexner incontinence scores were significantly better than baseline, in both groups, at 6 weeks and 6 months (P < 0.05), although the improvements were not significant at 12 months. There was no significant improvement for either agent, from baseline, in mean SF-36 scores at any follow-up sessions. There was no significant difference between the two bulking agents, with regard to both Wexner and SF-36 scores, at any of the follow-up sessions. Complications occurred in one patient in the PTQ group (perianal abscess) and did not occur in any of the patients in the Durasphere group. CONCLUSIONS This trial appears to show that both synthetic agents PTQ(®) and Durasphere(®) are effective and safe, although long-term improvement is limited. In this trial, there appears to be no difference in efficacy between the two agents, over a 12-month follow-up period.
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Comparative evaluation of fracture resistance under static and fatigue loading of endodontically treated teeth restored with carbon fiber posts, glass fiber posts, and an experimental dentin post system: an in vitro study.
Ambica, K, Mahendran, K, Talwar, S, Verma, M, Padmini, G, Periasamy, R
Journal of endodontics. 2013;(1):96-100
Abstract
INTRODUCTION This investigation sought to compare the fracture resistance under static and fatigue loading of endodontically treated teeth restored with fiber-reinforced composite posts and experimental dentin posts milled from human root dentin by using computer-aided design/computer-aided manufacturing. METHODS Seventy maxillary central incisors were obturated and divided into 4 groups: control group without any post (n = 10), carbon fiber post group (n = 20), glass fiber post group (n = 20), and dentin post group (n = 20). Control group teeth were prepared to a height of 5 mm. In all other teeth, post space was prepared; a post was cemented, and a core build-up was provided. Half the samples from each group were statistically loaded until failure, and the remaining half were subjected to cyclic loading, followed by monostatic load until fracture. RESULTS One-way analysis of variance and Bonferroni multiple comparisons revealed a significant difference among test groups. The control group demonstrated highest fracture resistance (935.03 ± 33.53 N), followed by the dentin post group (793.12 ± 33.69 N), glass fiber post group (603.44 ± 46.67 N), and carbon fiber post group (497.19 ± 19.27 N) under static loading. These values reduced to 786.69 ± 29.64 N, 646.34 ± 26.56 N, 470 ± 36.34 N, and 379.71 ± 13.95 N, respectively, after cyclic loading. CONCLUSIONS Results suggest that human dentin can serve as post material under static and fatigue loading. Although at an early stage in research, the use of dentin posts in root-filled teeth looks promising.
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Comparing alkaline and thermal disintegration characteristics for mechanically dewatered sludge.
Tunçal, T
Environmental technology. 2011;(13-14):1581-8
Abstract
Thermal drying is one of the advanced technologies ultimately providing an alternative method of sludge disposal. In this study, the drying kinetics of mechanically dewatered sludge (MDS) after alkaline and thermal disintegration have been studied. In addition, the effect of total organic carbon (TOC) on specific resistance to filtration and sludge bound water content were also investigated on freshly collected sludge samples. The combined effect of pH and TOC on the thermal sludge drying rate for MDS was modelled using the two-factorial experimental design method. Statistical assessment of the obtained results proposed that sludge drying potential has increased exponentially for both increasing temperature and lime dosage. Execution of curve fitting algorithms also implied that drying profiles for raw and alkaline-disintegrated sludge were well fitted to the Henderson and Pabis model. The activation energy of MDS decreased from 28.716 to 11.390 kJ mol(-1) after disintegration. Consequently, the unit power requirement for thermal drying decreased remarkably from 706 to 281 W g(-1) H2O.
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Can we predict carbon stocks in tropical ecosystems from tree diversity? Comparing species and functional diversity in a plantation and a natural forest.
Ruiz-Jaen, MC, Potvin, C
The New phytologist. 2011;(4):978-987
Abstract
• Linking tree diversity to carbon storage can provide further motivation to conserve tropical forests and to design carbon-enriched plantations. Here, we examine the role of tree diversity and functional traits in determining carbon storage in a mixed-species plantation and in a natural tropical forest in Panama. • We used species richness, functional trait diversity, species dominance and functional trait dominance to predict tree carbon storage across these two forests. Then we compared the species ranking based on wood density, maximum diameter, maximum height, and leaf mass per area (LMA) between sites to reveal how these values changed between different forests. • Increased species richness, a higher proportion of nitrogen fixers and species with low LMA increased carbon storage in the mixed-species plantation, while a higher proportion of large trees and species with high LMA increased tree carbon storage in the natural forest. Furthermore, we found that tree species varied greatly in their absolute and relative values between study sites. • Different results in different forests mean that we cannot easily predict carbon storage capacity in natural forests using data from experimental plantations. Managers should be cautious when applying functional traits measured in natural populations in the design of carbon-enriched plantations.
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The Monte Carlo code MCPTV--Monte Carlo dose calculation in radiation therapy with carbon ions.
Karg, J, Speer, S, Schmidt, M, Mueller, R
Physics in medicine and biology. 2010;(13):3917-36
Abstract
The Monte Carlo code MCPTV is presented. MCPTV is designed for dose calculation in treatment planning in radiation therapy with particles and especially carbon ions. MCPTV has a voxel-based concept and can perform a fast calculation of the dose distribution on patient CT data. Material and density information from CT are taken into account. Electromagnetic and nuclear interactions are implemented. Furthermore the algorithm gives information about the particle spectra and the energy deposition in each voxel. This can be used to calculate the relative biological effectiveness (RBE) for each voxel. Depth dose distributions are compared to experimental data giving good agreement. A clinical example is shown to demonstrate the capabilities of the MCPTV dose calculation.
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Comparison of DNA breaks at entrance channel and Bragg peak induced by fast C6+ ions--influence of the addition of platinum atoms on DNA.
Usami, N, Kobayashi, K, Hirayama, R, Furusawa, Y, Porcel, E, Lacombe, S, Le Sech, C
Journal of radiation research. 2010;(1):21-6
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Abstract
When energetic carbon ion beam (GeV range) goes through the matter, inelastic processes such as electronic ionization, molecular and nuclear fragmentation occur. For carbontherapy (hadrontherapy) purpose, it is of interest to compare the number of DNA breaks -single SSB or double DSB- for a given dose at the entrance channel and at the Bragg peak to look for a possible differential effect in the number of DNA breaks induced at these two locations. Samples of free plasmids DNA and complexes of plasmids DNA added with molecules containing platinum have been placed at different locations of an experimental setup simulating penetration depths of the ion beam in water and irradiated by carbon ions 290 MeV/amu. The DNA breaks have been quantified by subsequent electrophoresis on agarose gels. To disentangle the respective role of the direct and indirect effect, a free radical scavenger of hydroxyl radicals HO degree-dimethylsulfoxide DMSO- has been added in some of the experiments. In the range of Linear Energy Transfer-LET 13 - 110 keV/microm-, the number of the DSB was found to be constant versus the LET for a given dose. Contrary, the number of the SSB decreases at the Bragg peak compared to the entrance channel. In the presence of platinum, the number of single and double breaks was considerably enhanced, and follows a similar behaviour than in the free-DNA experiments. Quantitative results on DNA damages do not show significant enhancement due to the nuclear or to the molecular fragmentation in the present experiments.
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Global meta-analysis of wood decomposition rates: a role for trait variation among tree species?
Weedon, JT, Cornwell, WK, Cornelissen, JH, Zanne, AE, Wirth, C, Coomes, DA
Ecology letters. 2009;(1):45-56
Abstract
The carbon flux from woody debris, a crucial uncertainty within global carbon-climate models, is simultaneously affected by climate, site environment and species-based variation in wood quality. In the first global analysis attempting to explicitly tease out the wood quality contribution to decomposition, we found support for our hypothesis that, under a common climate, interspecific differences in wood traits affect woody debris decomposition patterns. A meta-analysis of 36 studies from all forested continents revealed that nitrogen, phosphorus, and C : N ratio correlate with decomposition rates of angiosperms. In addition, gymnosperm wood consistently decomposes slower than angiosperm wood within common sites, a pattern that correlates with clear divergence in wood traits between the two groups. New empirical studies are needed to test whether this difference is due to a direct effect of wood trait variation on decomposer activity or an indirect effect of wood traits on decomposition microsite environment. The wood trait-decomposition results point to an important role for changes in the wood traits of dominant tree species as a driver of carbon cycling, with likely feedback to atmospheric CO(2) particularly where angiosperm species replace gymnosperms regionally. Truly worldwide upscaling of our results will require further site-based multi-species wood trait and decomposition data, particularly from low-latitude ecosystems.
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The efficacy and tolerability of AST-120 (spherical carbon adsorbent) in active pouchitis.
Shen, B, Pardi, DS, Bennett, AE, Queener, E, Kammer, P, Hammel, JP, LaPlaca, C, Harris, MS
The American journal of gastroenterology. 2009;(6):1468-74
Abstract
OBJECTIVES Although a majority of patients with pouchitis respond favorably to antibiotic therapy, many relapse frequently, and nonabsorbable and non-antibiotic-based agents are desirable for reducing bacterial resistance and the systemic adverse effects associated with long-term antibiotic exposure. AST-120 (a spherical carbon adsorbent) comprises highly adsorptive, porous carbon microspheres with the ability to adsorb small-molecular-weight toxins, inflammatory mediators,and harmful bile acids. The aim of this pilot trial was to evaluate the efficacy and tolerability of AST-120 in the treatment of active pouchitis. METHODS Eligible patients were recruited from two subspecialty pouchitis clinics. Inclusion criteria were(i) ileal pouch-anal anastomosis performed for ulcerative colitis; (ii) active pouchitis with Pouchitis Disease Activity Index (PDAI) scores > or =7; and (iii) discontinuation of antibiotic therapy for at least 2 weeks. Exclusion criteria included Crohn's disease of the pouch, isolated cuffitis, pouch strictures, abscess, and sinuses. All eligible patients received AST-120 in 2-g sachets (oral) open label, thrice a day for 4 weeks. The primary efficacy end point was remission as defined by a PDAI score of < 7 points; the main secondary end point was clinical response, defined by a reduction of the PDAI score of > or =3 points. RESULTS Nineteen of 20 patients completed the trial. Eleven patients (55.0 % ) had a clinical response to the therapy and 10 patients (50.0 % ) entered remission. Median reduction in the PDAI symptom, endoscopy, and histology subscores, and PDAI total scores after 4 weeks were -2( P = 0.002), -2 ( P = 0.003), 0 ( P = 0.32), and -4 ( P = 0.001) points, respectively. The agent was well tolerated; one patient experienced transient mild elevation of alkaline phosphatase of uncertain significance and one patient experienced an upper respiratory infection after taking one dose of AST-120 and was excluded from the fi nal analysis for the calculation of pre- and post-trial PDAI scores. CONCLUSIONS AST-120 seems to be effective and well tolerated in treating patients with active pouchitis.A randomized, placebo-controlled trial is warranted for assessing the long-term efficacy and safety of AST-120 in the disease.
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Removal of refractory compounds from stabilized landfill leachate using an integrated H2O2 oxidation and granular activated carbon (GAC) adsorption treatment.
Kurniawan, TA, Lo, WH
Water research. 2009;(16):4079-91
Abstract
This study investigated the treatment performances of H(2)O(2) oxidation alone and its combination with granular activated carbon (GAC) adsorption for raw leachate from the NENT landfill (Hong Kong) with a very low biodegradability ratio (BOD(5)/COD) of 0.08. The COD removal of refractory compounds (as indicated by COD values) by the integrated H(2)O(2) and GAC treatment was evaluated, optimized and compared to that by H(2)O(2) treatment alone with respect to dose, contact time, pH, and biodegradability ratio. At an initial COD concentration of 8000 mg/L and NH(3)-N of 2595 mg/L, the integrated treatment has substantially achieved a higher removal (COD: 82%; NH(3)-N: 59%) than the H(2)O(2) oxidation alone (COD: 33%; NH(3)-N: 4.9%) and GAC adsorption alone (COD: 58%) at optimized experimental conditions (p< or =0.05; t-test). The addition of an Fe(II) dose at 1.8 g/L further improved the removal of refractory compounds by the integrated treatment from 82% to 89%. Although the integrated H(2)O(2) oxidation and GAC adsorption could treat leachate of varying strengths, treated effluents were unable to meet the local COD limit of less than 200 mg/L and the NH(3)-N of lower than 5 mg/L. However, the integrated treatment significantly improved the biodegradability ratio of the treated leachate by 350% from 0.08 to 0.36, enabling the application of subsequent biological treatments for complementing the degradation of target compounds in the leachate prior to their discharge.