5,381 research outputs found
Co-morbidity burden in Parkinsonâs disease : Comparison with controls and its influence on prognosis
Financial support This study was funded by Parkinsonâs UK, the Scottish Chief Scientist Office, NHS Grampian endowments, the BMA Doris Hillier award, RS Macdonald Trust, the BUPA Foundation, and SPRING. The funders had no involvement in the study. Acknowledgements We acknowledge funding for the PINE study from Parkinsonâs UK (G-0502, G-0914, G-1302), the Scottish Chief Scientist Office(CAF/12/05), the BMA Doris Hillier award, RS Macdonald Trust, the BUPA Foundation, NHS Grampian endowments and SPRING. We thank the patients and controls for their participation and the research staff who collected data and supported the study database.Peer reviewedPostprintPostprintPublisher PD
Titration of Monolayers
The early work on the effect of pH on ionizable materials at
aqueous interfaces and the consequent development of the concept
of an effective pH in the interface region, which differs from tnat
in aqueous bulk phase, are outlined. Properties as a function of pH
of monolayers of a variety of surfactant types, viz., weak and
nonelectrolytes (fatty acids, amines, amine oxides, alcohols, ethers),
intermediate strength electrolytes (alkyl phosphates), strong electrolytes
(alkyl sulfates and alkane sulfonates, both as spread a:nd
adsorbed monolayers) and two zwitterionic materials, are presented
in some detail. Use is made of the approaches of Schulman and
Hughes and of Davies for analysis of the results which are shown
generally to be consistent with a shift towards weakness of the
monolayer electrolyte because of the charge developed during its
ionization; exceptions are the zwitterionic materials. Points of
interest are (a) the need to invoke acid-soap formation to explain
the surface potential- pH data of close-packed fatty acid monolayers;
(b) a prevalent tendency for most of the anionic or nonionic
monolayers to form oxonium ions at \u27ery low pH; (c) the relatively
expanded nature of the uncharged form of monolayers of the highly
dipolar amine oxide compared to its ionized form; (d) definite indications of »weakness« in both spread and adsorbed films of long
chain sulfates and alkane sulfonates. A brief section on the influence
of pH on polyelectrolyte monolayers is included
Specific Counterion Effects in Surface and Colloid Chemistry. Ionized Monolayers
Data are presented on the effect of various monovalent
cations on the rr,-A and 8V-A characteristics of charged insoluble
monolayers. The following interaction sequences were established:
R-coo-, Li > Na > K > tetramethylammonium > tetraethylammonium;
R-S04-, Cs = Rb> K > Na> Li; R-N (CHah+. SCN >
>I> N03 >Br> Cl> F; R-NH(CH3)2+ and R-NHs+, Br> Cl.
The results thus parallel data on ion sequence effects reported in
other branches of colloid and physical chemistry. They are discussed
in the light of various hypotheses advanced to explain these
effects. The monolayer rr,-A curves were compared with those predicted
from theoretically derived equations of state: agreement was
generally poor
Adsorption of Surfactants on Mineral Solids
Factors influendng 1he adsorption of ionic surfactants on solids
are outlined. Emphasis is placed on the role of electrostatic forces
and of lateral association within adsorbed layers. MechanLsms
leading to charge gene.ration on solids are descdbed, and the dependence of adsorption on charge effects i\u27s mustrated by reference to
published data on a number of different solid surfactan:t systems.
It is shown how the electrostatic factor can be strongly modified ·
by the presence of inorganic salts. The importance of chain-chain
interactions is illustrated by the influence of chains length and
composition on adsorption, and also by the pH dependence of the
adsorption of long chain, weak electrolytes. This leads to a discussion
of the possible role of highly surface active long chain
complexes. Lastly, the influence of polymers on the adsorption
of surfactants is discussed
Conformal Field Theories, Representations and Lattice Constructions
An account is given of the structure and representations of chiral bosonic
meromorphic conformal field theories (CFT's), and, in particular, the
conditions under which such a CFT may be extended by a representation to form a
new theory. This general approach is illustrated by considering the untwisted
and -twisted theories, and respectively,
which may be constructed from a suitable even Euclidean lattice .
Similarly, one may construct lattices and by
analogous constructions from a doubly-even binary code . In the case when
is self-dual, the corresponding lattices are also. Similarly,
and are self-dual if and only if is. We show that
has a natural ``triality'' structure, which induces an
isomorphism and also a triality
structure on . For the Golay code,
is the Leech lattice, and the triality on is the symmetry which extends the natural action of (an
extension of) Conway's group on this theory to the Monster, so setting triality
and Frenkel, Lepowsky and Meurman's construction of the natural Monster module
in a more general context. The results also serve to shed some light on the
classification of self-dual CFT's. We find that of the 48 theories
and with central charge 24 that there are 39 distinct ones,
and further that all 9 coincidences are accounted for by the isomorphism
detailed above, induced by the existence of a doubly-even self-dual binary
code.Comment: 65 page
Charges, Monopoles and Duality Relations
A charge-monopole theory is derived from simple and self-evident postulates.
Charges and monopoles take an analogous theoretical structure. It is proved
that charges interact with free waves emitted from monopoles but not with the
corresponding velocity fields. Analogous relations hold for monopole equations
of motion. The system's equations of motion can be derived from a regular
Lagrangian function.Comment: 17 pages + 3 figures
- âŠ