232 research outputs found
Induction of triacylglycerol production in Chlamydomonas reinhardtii: Comparative analysis of different element regimes
Cataloged from PDF version of article.In this study, impacts of different element absence (nitrogen, sulfur, phosphorus and magnesium) and supplementation (nitrogen and zinc) on element uptake and triacylglycerol production was followed in wild type Chlamydomonas reinhardtii CC-124 strain. Macro- and microelement composition of C. reinhardtii greatly differed under element regimes studied. In particular, heavy metal quotas of the microalgae increased strikingly under zinc supplementation. Growth was suppressed, cell biovolume, carbohydrate, total neutral lipid and triacylglycerol levels increased when microalgae were incubated under these element regimes. Most of the intracellular space was occupied by lipid bodies under all nutrient starvations, as observed by confocal microscopy and transmission electron micrographs. Results suggest that sulfur, magnesium and phosphorus deprivations are superior to nitrogen deprivation for the induction triacylglycerol production in C. reinhardtii. On the other hand, FAME profiles of the nitrogen, sulfur and phosphorus deprived cells were found to meet the requirements of international standards for biodiesel. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved
Nitrogen and sulfur deprivation differentiate lipid accumulation targets of Chlamydomonas reinhardtii
Cataloged from PDF version of article.Nitrogen (N) and sulfur (S) have inter-related and distinct impacts on microalgal metabolism; with N starvation having previously been reported to induce elevated levels of the biodiesel feedstock material triacylglycerol (TAG), while S deprivation is extensively studied for its effects on biohydrogen production in microalgae.1,2 We have previously demonstrated that N- and S-starved cells of Chlamydomonas reinhardtii display different metabolic trends, suggesting that different response mechanisms exist to compensate for the absence of those two elements.3 We used C. reinhardtii CC-124 mt(-) and CC-125 mt(+) strains to test possible metabolic changes related to TAG accumulation in response to N and S deprivation, considering that gamete differentiation in this organism is mainly regulated by N.4 Our findings contribute to the understanding of microalgal response to element deprivation and potential use of element deprivation for biodiesel feedstock production using microalgae, but much remains to be elucidated on the precise contribution of both N and S starvation on microalgal metabolism. © 2012 Landes Bioscience
Effects of laser ablated silver nanoparticles on Lemna minor
Cataloged from PDF version of article.The present study investigates and models the effect of laser ablated silver nanoparticles (AgNPs) on the development of the aquatic macrophyte Lemna minor. Toxic effects of five different AgNP concentrations (8, 16, 32, 96 and 128μgL-1) on L. minor were recorded over seven days under simulated natural conditions. Biosorption of AgNPs by L. minor was modeled using four sorption isotherms, and the sorption behavior was found to agree most closely with the Langmuir-Freundlich model (R2=0.997). While toxic effects of AgNPs could be observed in all models and concentrations, the greatest increase in toxicity was in the 8-32μgL-1 range. Dry weight- and frond number-based inhibition experiments suggest that growth inhibition does not necessarily scale with AgNP concentration, and that slight fluctuations in inhibition rates exist over certain concentration ranges. Very close fits (R2=0.999) were obtained for all removal models, suggesting that the fluctuations are not caused by experimental variation. In addition, L. minor was found to be a successful bioremediation agent for AgNPs, and displayed higher removal rates for increasing AgNP doses. FT-IR spectroscopy suggests that carbonyl groups are involved in AgNP remediation. © 2014 Elsevier Ltd
Primary Molar Pulpotomies with Different Hemorrhage Control Agents and Base Materials: A Randomized Clinical Trial
Objective: To evaluate the clinical and radiographical success of primary molar pulpotomies which used 15.5% ferric sulfate (FS) or 1.25% sodium hypochlorite (NaOCl) for hemostasis and zinc oxide-eugenol (ZOE) and calcium hydroxide (CH) pastes as base materials.
Methods: In 29 healthy children, 80 primary molars were randomly allocated to one of the study groups: Group 1: FS-ZOE, Group 2: FS-CH, Group 3: NaOCl-ZOE, and Group 4: NaOCl-CH. After hemostasis with the respective solutions, pulp stumps and floor of the pulp chambers were covered with either ZOE or CH pastes. All teeth were restored with stainless steel crowns. Follow-up examinations were carried out at 1, 3, 6, and 12 months.
Results: One tooth in Group 1 and two teeth in Group 4 were extracted because of pain and periapial pathosis at sixth month. After 12 months, clinical success rates of pulpotomies in Groups 1-4 were 95%, 100%, 100%, and 89.5%, respectively. The differences were not significant (P = 0.548). Radiographic success rates for Groups 1-4 were 80%, 88.9%, 78.9%, and 84.2%, respectively. No statistically significant difference was found (P = 0.968). Pain on percussion was the most observed clinical finding. However, internal root resorption was the most common radiological finding and it was observed significantly more in mandibular primary molars (P \u3c 0.05).
Conclusion: Both ZOE and CH can be preferred as base materials after hemostasis achieved by the use of 15.5% FS or 1.25% NaOCl in primary tooth pulpotomy
Three-dimensional black holes, gravitational solitons, kinks and wormholes for BHT massive gravity
The theory of massive gravity in three dimensions recently proposed by
Bergshoeff, Hohm and Townsend (BHT) is considered. At the special case when the
theory admits a unique maximally symmetric solution, a conformally flat space
that contains black holes and gravitational solitons for any value of the
cosmological constant is found. For negative cosmological constant, the black
hole is characterized in terms of the mass and the "gravitational hair"
parameter, providing a lower bound for the mass. For negative mass parameter,
the black hole acquires an inner horizon, and the entropy vanishes at the
extremal case. Gravitational solitons and kinks, being regular everywhere, are
obtained from a double Wick rotation of the black hole. A wormhole solution in
vacuum that interpolates between two static universes of negative spatial
curvature is obtained as a limiting case of the gravitational soliton with a
suitable identification. The black hole and the gravitational soliton fit
within a set of relaxed asymptotically AdS conditions as compared with the ones
of Brown and Henneaux. In the case of positive cosmological constant the black
hole possesses an event and a cosmological horizon, whose mass is bounded from
above. Remarkably, the temperatures of the event and the cosmological horizons
coincide, and at the extremal case one obtains the analogue of the Nariai
solution, . A gravitational soliton is also obtained
through a double Wick rotation of the black hole. The Euclidean continuation of
these solutions describes instantons with vanishing Euclidean action. For
vanishing cosmological constant the black hole and the gravitational soliton
are asymptotically locally flat spacetimes. The rotating solutions can be
obtained by boosting the previous ones in the plane.Comment: Talk given at the "Workshop on Gravity in Three Dimensions," 14-24
April 2009, ESI, Vienna. 30 pages, 6 figures. V2: minor changes and section 6
slightly improved. Last version for JHE
Bending AdS Waves with New Massive Gravity
We study AdS-waves in the three-dimensional new theory of massive gravity
recently proposed by Bergshoeff, Hohm, and Townsend. The general configuration
of this type is derived and shown to exhibit different branches, with different
asymptotic behaviors. In particular, for the special fine tuning
, solutions with logarithmic fall-off arise, while in the
range , spacetimes with Schrodinger isometry group are admitted
as solutions. Solutions that are asymptotically AdS, both for
Brown-Henneaux and for the weakened boundary conditions, are also identified.
The metric function that characterizes the profile of the AdS-wave behaves as a
massive excitation on the spacetime, with an effective mass given by
. For the critical value , the value of
the effective mass precisely saturates the Breitenlohner-Freedman bound for the
AdS space where the wave is propagating on. The analogies with the AdS-wave
solutions of topologically massive gravity are also discussed. Besides, we
consider the coupling of both massive deformations to Einstein gravity and find
the exact configurations for the complete theory, discussing all the different
branches exhaustively. One of the effects of introducing the Chern-Simons
gravitational term is that of breaking the degeneracy in the effective mass of
the generic modes of pure New Massive Gravity, producing a fine structure due
to parity violation. Another effect is that the zoo of exact logarithmic
specimens becomes considerably enlarged.Comment: 9 pages. Minor typos correcte
The General Supersymmetric Solution of Topologically Massive Supergravity
We find the general fully non-linear solution of topologically massive
supergravity admitting a Killing spinor. It is of plane-wave type, with a null
Killing vector field. Conversely, we show that all solutions with a null
Killing vector are supersymmetric for one or the other choice of sign for the
Chern-Simons coupling constant \mu. If \mu does not take the critical value
\mu=\pm 1, these solutions are asymptotically regular on a Poincar\'e patch,
but do not admit a smooth global compactification with boundary S^1\times\R. In
the critical case, the solutions have a logarithmic singularity on the boundary
of the Poincar\'e patch. We derive a Nester-Witten identity, which allows us to
identify the associated charges, but we conclude that the presence of the
Chern-Simons term prevents us from making a statement about their positivity.
The Nester-Witten procedure is applied to the BTZ black hole.Comment: Minor correction
A Study of Wall-Crossing: Flavored Kinks in D=2 QED
We study spectrum of D=2 N=(2,2) QED with N+1 massive charged chiral
multiplets, with care given to precise supermultiplet countings. In the
infrared the theory flows to CP^N model with twisted masses, where we construct
generic flavored kink solitons for the large mass regime, and study their
quantum degeneracies. These kinks are qualitatively different and far more
numerous than those of small mass regime, with features reminiscent of
multi-pronged (p,q) string web, complete with the wall-crossing behavior. It
has been also conjectured that spectrum of this theory is equivalent to the
hypermultiplet spectrum of a certain D=4 Seiberg-Witten theory. We find that
the correspondence actually extends beyond hypermultiplets in D=4, and that
many of the relevant indices match. However, a D=2 BPS state is typically
mapped to several different kind of dyons whose individual supermultiplets are
rather complicated; the match of index comes about only after summing over
indices of these different dyons. We note general wall-crossing behavior of
flavored BPS kink states, and compare it to those of D=4 dyons.Comment: 47 pages, 5 figures; typos fixed; references adde
International Veterinary Epilepsy Task Force Consensus Proposal: Outcome of therapeutic interventions in canine and feline epilepsy
Common criteria for the diagnosis of drug resistance and the assessment of outcome are needed urgently as a prerequisite for standardized evaluation and reporting of individual therapeutic responses in canine epilepsy. Thus, we provide a proposal for the definition of drug resistance and partial therapeutic success in canine patients with epilepsy. This consensus statement also suggests a list of factors and aspects of outcome, which should be considered in addition to the impact on seizures. Moreover, these expert recommendations discuss criteria which determine the validity and informative value of a therapeutic trial in an individual patient and also suggest the application of individual outcome criteria. Agreement on common guidelines does not only render a basis for future optimization of individual patient management, but is also a presupposition for the design and implementation of clinical studies with highly standardized inclusion and exclusion criteria. Respective standardization will improve the comparability of findings from different studies and renders an improved basis for multicenter studies. Therefore, this proposal provides an in-depth discussion of the implications of outcome criteria for clinical studies. In particular ethical aspects and the different options for study design and application of individual patient-centered outcome criteria are considered
Vaccination coverage and reasons for non-vaccination in a district of Istanbul
BACKGROUND: In order to control and eliminate the vaccine preventable diseases it is important to know the vaccination coverage and reasons for non-vaccination. The primary objective of this study was to determine the complete vaccination rate; the reasons for non-vaccination and the predictors that influence vaccination of children. The other objective was to determine coverage of measles vaccination of the Measles Immunization Days (MID) 2005 for children aged 9 month to 6 years in a region of Umraniye, Istanbul, Turkey. METHODS: A '30 × 7' cluster sampling design was used as the sampling method. Thirty streets were selected at random from study area. Survey data were collected by a questionnaire which was applied face to face to parents of 221 children. A Chi-square test and logistic regression was used for the statistical analyses. Content analysis method was used to evaluate the open-ended questions. RESULTS: The complete vaccination rate for study population was 84.5% and 3.2% of all children were totally non-vaccinated. The siblings of non-vaccinated children were also non-vaccinated. Reasons for non-vaccination were as follows: being in the village and couldn't reach to health care services; having no knowledge about vaccination; the father of child didn't allow vaccination; intercurrent illness of child during vaccination time; missed opportunities like not to shave off a vial for only one child. In logistic regression analysis, paternal and maternal levels of education and immigration time of both parents to Istanbul were found to influence whether children were completely vaccinated or non-vaccinated. Measles vaccination coverage during MID was 79.3%. CONCLUSION: Efforts to increase vaccination coverage should take reasons for non-vaccination into account
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