Two novel stereoregular poly(phenylacetylene)s bearing a phosphonic acid residue (poly-1) and its monoethyl ester (poly-2) as pendants were prepared by the polymerization of diethyl (4ethynylphenyl)phosphonate followed by hydrolysis of the diethyl ester groups and polymerization of ethyl (4-ethynylphenyl)phosphonate, respectively. The polymers were found to form a predominantly one-handed helical conformation upon complexation with various chiral amines through noncovalent acid-base interactions in dimethyl sulfoxide (DMSO). The complexes exhibited an induced circular dichroism (ICD) in the UV-visible region of the polymer backbones. In particular, poly-2 is an induced helical polymer more sensitive to the chirality of amines than poly-1 and poly((4-carboxyphenyl)acetylene) and yields the same Cotton effect sign when complexed with chiral amines of the same absolute configuration. Moreover, the macromolecular helicity of poly-1 and poly-2 induced by chiral amines was "memorized" after the chiral amines were completely removed and replaced with various achiral diamines and oligoamines in DMSO. In sharp contrast to the same memory effect on the induced helical poly((4carboxyphenyl)acetylene), the helical structures of poly-1 and poly-2 could not be efficiently maintained by achiral monoamines. The effect of the structure of the achiral diamines and oligoamines on the efficiency of the helicity retention and the stability of the memorized polymers were also investigated.
International audienceNovel polyacetylenes bearing an optically active or racemic [6]helicene unit as the pendant groups directly bonded to the main-chain (poly-1s) were prepared by the polymerization of the corresponding acetylenes (1-rac, 1-P, and 1-M) with a rhodium catalyst. The optically active polyacetylenes (poly-1-P and poly-1-M) formed a preferred-handed helical conformation biased by the optically active helicene pendants, resulting in the induced circular dichroism (ICD) in their π-conjugated polymer backbone regions. The optically active helical polymers, when employed as an enantioselective adsorbent, showed a high chiral recognition ability towards racemates, such as the monomeric [6]helicene and 1,1’-binaphthyl analogues, and enantioselectively adsorbed one of the enantiomers
We quantified net changes to the area and quality of native vegetation after the introduction of biodiversity offsetting in New South Wales, Australia-a policy intended to "prevent broad-scale clearing of native vegetation unless it improves or maintains environmental values." Over 10 years, a total of 21,928 ha of native vegetation was approved for clearing under this policy and 83,459 ha was established as biodiversity offsets. We estimated that no net loss in the area of native vegetation under this policy will not occur for 146 years. This is because 82% of the total area offset was obtained by averting losses to existing native vegetation and the rate that these averted losses accrue was over-estimated in the policy. There were predicted net gains in 10 of the 14 attributes used to assess the quality of habitat. An overall net gain in the quality of habitat was assessed under this policy by substituting habitat attributes that are difficult to restore (e.g. mature trees) with habitat attributes for which restoration is relatively easy (e.g. tree seedlings). Long-term rates of annual deforestation did not significantly change across the study area after biodiversity offsetting was introduced. Overall, the policy examined here provides no net loss of biodiversity: (i) many generations into the future, which is not consistent with intergenerational equity; and (ii) by substituting different habitat attributes, so gains are not equivalent to losses. We recommend a number of changes to biodiversity offsetting policy to overcome these issues.
To promote Bio-Energy with Carbon dioxide Capture and Storage (BECCS), which aims to replace fossil fuels with bio energy and store carbon underground, and Reducing Emissions from Deforestation and forest Degradation (REDD+), which aims to reduce the carbon emissions produced by forest degradation, it is important to build forest management plans based on the scientific prediction of forest dynamics. For Measurement, Reporting and Verification (MRV) at an individual tree level, it is expected that techniques will be developed to support forest management via the effective monitoring of changes to individual trees. In this study, an end-to-end process was developed: (1) detecting individual trees from Unmanned Aerial Vehicle (UAV) derived digital images; (2) estimating the stand structure from crown images; (3) visualizing future carbon dynamics using a forest ecosystem process model. This process could detect 93.4% of individual trees, successfully classified two species using Convolutional Neural Network (CNN) with 83.6% accuracy and evaluated future ecosystem carbon dynamics and the source-sink balance using individual based model FORMIND. Further ideas for improving the sub-process of the end to end process were discussed. This process is expected to contribute to activities concerned with carbon management such as designing smart utilization for biomass resources and projecting scenarios for the sustainable use of ecosystem services.
The alteration of p53 tumor suppressor gene was studied in 48 patients with B-cell lymphoma. A sequential combined technique of polymerase chain reaction-mediated single-strand conformational polymorphism (PCR- SSCP) or reverse transcription (RT)-PCR-SSCP and direct sequencing were used as a simple and sensitive approach to analyze nucleotide changes. By these methods, we identified 8 missense point mutations and 2 codon deletions in 9 of the 48 patients. These mutations were located in or close to the evolutionally highly conserved regions of the p53 gene. Eight of nine patients having p53 gene alterations were in advanced clinical stage (IV). It is the first report of p53 gene mutations in follicular and diffuse lymphoma. These observations suggest that the p53 gene alteration may play an important role in lymphomagenesis and/or disease progression in some types of B-cell lymphoma.
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