Saccharomyces cerevisiae-based system for studying clustered DNA damages

DNA-damaging agents can induce clustered lesions or multiply damaged sites (MDSs) on the same or opposing DNA strands. In the latter, attempts to repair MDS can generate closely opposed single-strand break intermediates that may convert non-lethal or mutagenic base damage into double-strand breaks (DSBs). We constructed a diploid S. cerevisiae yeast strain with a chromosomal context targeted by integrative DNA fragments carrying different damages to determine whether closely opposed base damages are converted to DSBs following the outcomes of the homologous recombination repair pathway. As a model of MDS, we studied clustered uracil DNA damages with a known location and a defined distance separating the lesions. The system we describe might well be extended to assessing the repair of MDSs with different compositions, and to most of the complex DNA lesions induced by physical and chemical agents

Identifying Where REDD+ Financially Out Competes Oil Palm in Floodplain Landscapes Using a Fine-Scale Approach

Reducing Emissions from Deforestation and forest Degradation (REDD+) aims to avoid forest conversion to alternative land-uses through financial incentives. Oil-palm has high opportunity costs, which according to current literature questions the financial competitiveness of REDD+ in tropical lowlands. To understand this more, we undertook regional finescale and coarse-scale analyses (through carbon mapping and economic modelling) to assess the financial viability of REDD+ in safeguarding unprotected forest (30,173 ha) in the Lower Kinabatangan floodplain in Malaysian Borneo. Results estimate 4.7 million metric tons of carbon (MgC) in unprotected forest, with 64% allocated for oil-palm cultivations. Through fine-scale mapping and carbon accounting, we demonstrated that REDD+ can outcompete oil-palm in regions with low suitability, with low carbon prices and low carbon stock. In areas with medium oil-palm suitability, REDD+ could outcompete oil palm in areas with: very high carbon and lower carbon price; medium carbon price and average carbon stock; or, low carbon stock and high carbon price. Areas with high oil palm suitability, REDD + could only outcompete with higher carbon price and higher carbon stock. In the coarse-scale model, oil-palm outcompeted REDD+ in all cases. For the fine-scale models at the landscape level, low carbon offset prices (US $3 MgCO2e) would enable REDD+ to outcompete oil-palm in 55$27 million to secure these areas for 25 years. Higher carbon offset price (US $30 MgCO2e) would increase the competitiveness of REDD+ within the landscape but would still only capture between 69$380–416 million in carbon financing. REDD+ has been identified as a strategy to mitigate climate change by many countries (including Malaysia). Although REDD+ in certain scenarios cannot outcompete oil palm, this research contributes to the global REDD+ debate by: highlighting REDD+ competitiveness in tropical floodplain landscapes; and, providing a robust approach for identifying and targeting limited REDD+ funds

Interest of functionalized mesoporous silica-based materials for electrochemical sensing

Congrès du 13.11.2005 au 18.11.200

Structural characterization and electrochemical behavior of titanium carbon thin films

Symposium K on Protective Coatings and Thin Films held at the European-Materials-Research-Society Spring Meeting (E-MRS), Nice, FRANCE, MAY 09-13, 2011In the present work we report the results concerning the synthesis of Ti-C films obtained by a co-sputtering process of both titanium and graphite targets. The titanium content within the coatings has been adjusted in a wide range, allowing different structures of the films, to be formed. The chemical composition of the films was determined by X-ray photoelectron spectroscopy (XPS). Phase structure was analyzed by grazing angle X-ray diffraction (GXRD), while the morphology and microstructure were investigated by scanning electron microscopy (SEM). The possibility of using the resulting materials for electrochemical applications was also examined. For these purposes, the Ti-C films used as electrodes were investigated in terms of both reactivity and stability. Electrochemical investigations were carried out by using cyclic voltammetry and spectroscopy electrochemical techniques. (C) 2011 Elsevier B.V. All rights reserved

Early prediction of the impact of public health policies on obesity and lifetime risk of type 2 diabetes: A modelling approach.

International audienceObjectiveHelp public health decision-making requires a better understanding of the dynamics of obesity and type 2 diabetes and an assessement of different strategies to decrease their burdens.MethodsBased on 97,848 individual data, collected in the French Health, Health Care and Insurance Survey over 1998–2014, a Markov model was developed to describe the progression of being overweight to obesity, and the onset of type 2 diabetes. This model traces and predicts 2022–2027 burdens of obesity and type 2 diabetes, and lifetime risk of diabetes, according to different scenarios aiming at minimum to stabilize obesity at 5 years.ResultsEstimated risks of type 2 diabetes increase from 0.09% (normal weight) to 1.56% (obesity II-III). Compared to the before 1995 period, progression risks are estimated to have nearly doubled for obesity and tripled for type 2 diabetes. Consequently, over 2022–2027, the prevalence of obesity and type 2 diabetes will continue to increase from 17.3% to 18.2% and from 7.3% to 8.1%, respectively. Scenarios statibilizing obesity would require a 22%-decrease in the probability of move up (scenario 1) or a 33%-increase in the probability of move down (scenario 2) one BMI class. However, this stabilization will not affect the increase of diabetes prevalence whereas lifetime risk of diabetes would decrease (30.9% to 27.0%). Combining both scenarios would decrease obesity by 9.9%. Only the prevalence of obesity III shows early change able to predict the outcome of a strategy: for example, 6.7%-decrease at one year, 13.3%-decrease at two years with scenario 1 stabilizing obesity at 5 years.ConclusionsPrevalences of obesity and type 2 diabetes will still increase over the next 5 years. Stabilizing obesity may decrease lifetime risks of type 2 diabetes without affecting its short-term prevalence. Our study highlights that, to early assess the effectiveness of their program, public health policy makers should rely on the change in prevalence of obesity III

Two-step approach for the nanofabrication of highly ordered ultra-long porous gold nanowires with an adjustable porosity for SERS-based sensors

Recently, nanoporous gold has been pointed out as a promising candidate for the development of SERS-based sensors for the detection of environmental toxins and small molecules [1]. One way to improve the detection ability of such sensors is by engineering the porosity and shape of nanoporous material. In this work we report on a versatile two-step approach for the synthesis of porous nanowires involving plasma deposition of gold-copper alloy on a nanograted substrate followed by a selective electrochemical etching. The relevance of the approach is its ability to prepare highly ordered ultra-long porous gold nanowires with an adjustable porosity and a length up to the macroscale. The resulting gold porous nanowire exhibits a very high roughness and high specific surface area suitable for highly sensitive detection of small molecules by SERS. References: [1] L. Zhang, H. Chang, A. Hirata, H. Wu,Q.-K. Xue and M. Chen, ACS Nano 7, 4595 (2013