117 research outputs found
Nine-membered cyclodepsitripeptide systems containing the retroisomeric sequence of ergot-peptides
No full textChemInform Abstract: Dicobalt Hexacarbonyl Derivatives of Chiral Acetylenes.
No full text(mu(2)-RC(2)R')Co-2(CO)(6) complexes are prepared where R not equal R' and one of these substituents is a chiral organic group. The structures of the 11 complexes (10 new) range from the simplest possible chiral acetylenic hydrocarbon derivative (S-3-methyl-1-pentyne 1a) to ethynylsteroid (1f, 1g, 1h) and ethynylcodeine (1i, 1j, 1k) derivatives. The CD spectra are reported and the results are analysed in terms of a quadrant rule. The CD spectra show that in all complexes the Co-2(CO)(6) fragment of the molecule gets chirally perturbed. The reasons for the chiral perturbation include apolar repulsing (dominant for the hydrocarbon acetylenes) and polar attractive (''autosolvation''; dominant for acetylenes with polar hetero-atom containing substituents) forces
Untangling the Relationship Between Attribution and Due Diligence in International Investment Law and Beyond
No full textIn international investment law, states have an obligation to protect foreign investors against certain interferences by their own organs as well as private actors. In the first case, state responsibility emerges from breach of the obligation to refrain from a wrongful activity and is attached to the state through the attribution of the acts of its organs. In contrast, when the harm is caused by non-state actors, a state can incur responsibility if it fails to exercise due diligence in protecting investors. Can a due diligence standard be utilized also to determine state responsibility when the injury was not caused at the hands of private actors? Departing from doctrine, this chapter argues that it can, articulating legal, policy and theoretical justifications, relying in particular on the concept of risk. It shows how this approach converges with other areas of international law, especially international humanitarian law and international human rights law
Environmental DNA Plumes: Linking Fish Farm eDNA to Microbial Communities and Novel Detection of Transgenic eDNA
No full textFinfish aquaculture has been on a steady rise, and to match human consumption an increase of open water fish farming is inevitable; however, the impacts of rearing high densities of fish on the surrounding ecosystem remains unclear. Transgenic fish have begun to be implemented in aquaculture to improve traits such as growth rate and feeding efficiency. However, concerns about the potential ecological impact if escaped transgenic organisms are diverse and widespread. Here we characterize the eDNA “plume” from an open water Oncorhynchus tshawystcha farm, and from a transgenic Oncorhynchus kistuch rearing facility. We utilize eDNA as a biomarker of sloughed Chinook salmon DNA from the farm and test for farm effects on bacterial community changes. We found evidence of an overall seasonal effect on eDNA concentration and localized distance effects relative to the farm in the fall. Our BC analyses showed strong seasonal effects as well as evidence of a distance (from the farm) on BC diversity. Despite the well-mixed characteristics of the sampled bay our findings indicate a radial effect of the fish farm plume on the surrounding waters. We also designed a transgene-specific assay to detect transgenic Coho salmon without interference from the wild-type genome and establish the range of detection from an effluent pipe. Our transgene-specific assay detected the growth hormone construct from environmental samples to 10 m from the effluent pipe, as well as two samples 150 m away and 1300m away from the effluent pipe, detecting extremely low traces of transgene DNA copies. This spatial inconsistency in transgenic eDNA detection may be due to sloughed organic matter accumulating, rather then breaking down into a homogenous mixture in marine water. This work establishes how eDNA can be used as a valuable tool for marine surveillance, providing data on the distribution of finfish DNA from a point source and identifying ecological impacts on the surrounding aquatic environment
Chiroptical Properties and Conformation of 4,5-Saturated Derivatives of 5-Aryl-1,4-benzodiazepin-2-ones
No full textCD spectra of a series of 5-aryl-7-chloro-l,3,4,5-tetrahydro-
2H-l,4-benzodiazepin-2-one derivatives having different substituents
at positions 1, 3, 4, and 5 were studied. The absolute configuration
at C-5 of two homochiral analogues, 1 and 2, having
enantiomorphous ring conformations was determined on the basis
of chiroptical correlations and theoretical calculations. The latter
have shown that the optical activity mainly originates from the
one-electron mechanism and is determined by the helicity of the
diazepine ring, i. e. by the inherent chirality of the partial chromophore 4-chloro-N,2-dimethyl-formanilide. Exciton inter action s
between transitions of the two arornatic chromophores A and C
also give a significant contribution to chiroptical properties. By applying simple chiroptical rules dedueed from experimental
spectra and supported by calculations, the stereochemistry (absolute
conformation and configuration), of 3,5-disubstituted cis and
trans epimeric pairs (7-17) was revealed
Global surface temperatures
No full textThe Sixth Assessment Report of the Intergovernmental Panel on Climate Change stated that ”it is unequivocal that human influence has warmed the atmosphere, ocean and land”. One key piece of evidence for this is the global average of the instrumental record of surface temperature. A change in surface temperature of 1.5˚C relative to a reference “pre-industrial” period is the measure internationally agreed to mark the transition to a climate where dangerous impacts become common. This chapter will discuss the observational evidence that ensures a reliable record of the changing temperature, some of the challenges that have been overcome, and some that remain in improving that record and more fully understanding its uncertainty
ChemInform Abstract: Nitrogen Bridgehead Compounds. Part 71. Chiroptical Properties of 9‐Halo Derivatives (I) of 6,7,8,9‐Tetrahydro‐4H‐pyrido(1,2‐a)pyrimidin‐4one and Its 3‐Carboxy Derivative.
No full textChemInform Abstract: Simple and Condensed β-Lactams. Part 26. Studies into 4-(Pyridyl) azetidin-2-ones.
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