16,199 research outputs found
Continuity of symplectically adjoint maps and the algebraic structure of Hadamard vacuum representations for quantum fields on curved spacetime
We derive for a pair of operators on a symplectic space which are adjoints of
each other with respect to the symplectic form (that is, they are sympletically
adjoint) that, if they are bounded for some scalar product on the symplectic
space dominating the symplectic form, then they are bounded with respect to a
one-parametric family of scalar products canonically associated with the
initially given one, among them being its ``purification''. As a typical
example we consider a scalar field on a globally hyperbolic spacetime governed
by the Klein-Gordon equation; the classical system is described by a symplectic
space and the temporal evolution by symplectomorphisms (which are
symplectically adjoint to their inverses). A natural scalar product is that
inducing the classical energy norm, and an application of the above result
yields that its ``purification'' induces on the one-particle space of the
quantized system a topology which coincides with that given by the two-point
functions of quasifree Hadamard states. These findings will be shown to lead to
new results concerning the structure of the local (von Neumann)
observable-algebras in representations of quasifree Hadamard states of the
Klein-Gordon field in an arbitrary globally hyperbolic spacetime, such as local
definiteness, local primarity and Haag-duality (and also split- and type
III_1-properties). A brief review of this circle of notions, as well as of
properties of Hadamard states, forms part of the article.Comment: 42 pages, LaTeX. The Def. 3.3 was incomplete and this has been
corrected. Several misprints have been removed. All results and proofs remain
unchange
Inhibition of monocyte complement receptor enhancement by low molecular weight material from human lung cancers
We have studied the effect of dialysates from lung cancer homogenates to alter both the expression of complement (C3b) receptors per se and also to inhibit leucoattractant-induced enhancement of complement rosettes on monocytes from healthy individuals. Enhancement and enhancement-inhibition by tumour extracts were compared with material derived from normal lung excised from distance from the tumour. There was no significant difference between tumour homogenate (TH) and normal lung homogenate (NLH) in terms of enhancement of complement rosettes per se. In contrast, TH produced a dose- and time-dependent inhibition of leucoattractant-induced enhancement of C3b rosettes which was significantly different from that obtained with NLH. This enhancement-inhibition was observed with four undifferentiated, four squamous and three adenocarcinomas of lung. The degree of enhancement-inhibition was not related to the type of tumour or varying accompanying histological features such as necrosis and the degree of infiltration with inflammatory cells. Following gel filtration on Sephadex G-50 each type of cancer gave a major peak of inhibitory activity which eluted with molecules having an apparent molecular size of approximately 3,000 daltons. A second larger peak (8,000-10,000 daltons) was also detected with extracts from the undifferentiated and adenocarcinomas. These results support previous findings, mainly from experimental animals, indicating that 'anti-macrophage/monocyte principles' are elaborated from certain tumour types
Studies on allergy and inflammation
The enclosed papers have been classified into five
major sections whose content is as follows:SECTION A - The eosinophil leucocyte
The first works are studies on the mechanisms of
eosinophil accumulation following antigen-antibody
(1,2 )
reactions in guinea pig skin. ' y These were extended
to observations on eosinophil chemotaxis in vitro in
relation to the complement system. (3,4)The eosinophil chemotactic factor of anaphylaxis
(ECF-A) was first described in 1971.(5,6) Interactions
between ECF-A and complement-derived eosinophilotactic
factors were reported later(7) as were investigations on
the chemical characterisation of ECF-A.(8) Inhibition
of eosinophil chemotaxis by an agent related to disodium
cromoglycate is also described.(9) Other eosinophil
chemotactic agents thought to participate in eosinophil
accumulation in vivo include material derived from
Hodgkin's lymph node cells,histamine and one of its
major catabolites, imidazole acetic acid.(11) The interactions of these agents both in vitro and in vivo were
extensively studied(12,13) and extended to investigations
on the response of eosinophils to an ECF-A tetrapeptide
and histamine in various disease states(14) as well as
the capacity of these agents to mobilise eosinophils in
the skin of atopic and non-atopic human volunteers.(15)Evidence was provided that one of the functions of
the eosinophil in allergic tissue reactions may be its
capacity to inhibit mast cell 'regranulation'.(16)Membrane receptors for IgG and complement (C4, C3b
and C3d) on human eosinophils and neutrophils and their
relation to eosinophilia were described(17) and this work
led to the observation that the ECF-A tetrapeptides and
histamine both selectively enhance human eosinophil
complement receptors.(18)This work, and those of others, was reviewed in
several articles.(19-26)SECTION B - Mediators of hypersensitivityIn 1974 it was shown that both slow reacting substance
of anaphylaxis (SRS-A) and ECF-A were released from
passively sensitized skin following interaction with
specific antigen.(27) The inactivation of SRS-A by the
arylsulphatase contained in various tissues was
described(28`) and later it was shown that appreciable
amounts of human SRS-A were present in lung as a preformed mediator.(29)A number of miscellaneous papers relating to
mediators are contained in this section: these include
an observation on complement activation by Corynebacterium
parvum;(30) some chemical and physical properties of
synthetic human fibrinopeptides(31) and the description of
a primate macrophage-cytophilic antibody(32)A review of the various biological pathways associated
with the inflammatory response as they relate to complications of blood transfusion were described in a review
article.(33)SECTION C - Studies on chemotaxisThis section contains papers on chemotaxis of
(34)
neutrophils, monocytes and basophils. Particular
attention was given to the identification of chemotactic
agents associated with Hageman factor-dependent path¬
ways(35), fibrin, formation(36,37) and fibrinolysis.(38,39)There is a study on the relation between neutrophil
accumulation in vivo and agents that are chemotactic
in vitro.(40)Alterations in monocyte chemotaxis in bronchial
carcinoma were described.(41)Much of this work, especially the relation between
chemotaxis and haemostasis, was reviewed in 1975.(42)SECTION D - Clinical studiesThis section contains reports on alterations in the
complement systems in bronchial asthma(43-45) and the
significance of immunoglobulins and complement in pleural effusions associated with bronchial carcinoma.(46)
Studies on mediators of hypersensitivity in chronic
bronchitis and asthma and their modulation by pharmacological agents are also described.(47,48)Detailed immunological investigations of two clinical
cases, one of chronic benign neutropenia(49) and the other
on the effect of transfer factor in chronic mucocutaneous
candidiasis,(50) are described.A consideration of how coagulation and other
biological systems may interrelate in the context of
'Stroke' was discussed in a review article.(51)SECTION E - MethodologyThis section contains two articles on methodology,
one on the preparation of transfer factor( 52) and the
other on tests of immune function.(53
Fractional diffusion models of cardiac electrical propagation: role of structural heterogeneity in dispersion of repolarization
Structural heterogeneity constitutes one of the main substrates influencing impulse propagation in living tissues. In cardiac muscle, improved understanding on its role is key to advancing our interpretation of cell-to-cell coupling, and how tissue structure modulates electrical propagation and arrhythmogenesis in the intact and diseased heart. We propose fractional diffusion models as a novel mathematical description of structurally heterogeneous excitable media, as a mean of representing the modulation of the total electric field by the secondary electrical sources associated with tissue inhomogeneities. Our results, validated against in-vivo human recordings and experimental data of different animal species, indicate that structural heterogeneity underlies many relevant characteristics of cardiac propagation, including the shortening of action potential duration along the activation pathway, and the progressive modulation by premature beats of spatial patterns of dispersion of repolarization. The proposed approach may also have important implications in other research fields involving excitable complex media
Hadamard States and Adiabatic Vacua
Reversing a slight detrimental effect of the mailer related to TeXabilityComment: 10pages, LaTeX (RevTeX-preprint style
Nonprofit Hospitals: The Relationship between Charitable Tax Exemptions and Medical Care for Indigents
Monocyte chemotaxis in bronchial carcinoma and cigarette smokers.
Chemotaxis of blood monocytes was measured in 31 patients with bronchial carcinoma and 19 cigarette smokers. Thirteen patients with metastatic bronchial carcinoma had significantly less (P less than 0.005) chemotactic response than matched controls. Those with disease confined to the chest, or with recurrent or operable bronchial carcinoma, had no significant depression of monocyte chemotaxis. There was also no significant difference in monocyte chemotaxis between cigarette smokers and matched controls. These results support the concept that in human cancer there is a defect in monocyte chemotaxis, but in bronchial carcinoma significant depression was only apparent in those with advanced disease
High-j single-particle neutron states outside the N=82 core
The behaviour of the i13/2 and h9/2 single-neutron strength was studied with
the (4He,3He) reaction on 138Ba, 140Ce, 142Nd and 144Sm targets at a beam
energy of 51 MeV. The separation between the single-neutron states i13/2 and
h9/2 was measured in N =83 nuclei with changing proton number. To this end
spectroscopic factors for states populated in high-l transfer were extracted
from the data. Some mixing of l=5 and 6 strength was observed with states that
are formed by coupling the f7/2 state to the 2+ and 3- vibrational states and
the mixing matrix elements were found to be remarkably constant. The centroids
of the strength indicate a systematic change in the energies of the i13/2 and
h9/2 single-neutron states with increasing proton number that is in
quantitative agreement with the effects expected from the tensor interaction.Comment: 12 pages of text, 3 diagram
Random field spin models beyond one loop: a mechanism for decreasing the lower critical dimension
The functional RG for the random field and random anisotropy O(N)
sigma-models is studied to two loop. The ferromagnetic/disordered (F/D)
transition fixed point is found to next order in d=4+epsilon for N > N_c
(N_c=2.8347408 for random field, N_c=9.44121 for random anisotropy). For N <
N_c the lower critical dimension plunges below d=4: we find two fixed points,
one describing the quasi-ordered phase, the other is novel and describes the
F/D transition. The lower critical dimension can be obtained in an
(N_c-N)-expansion. The theory is also analyzed at large N and a glassy regime
is found.Comment: 4 pages, 5 figure
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