859 research outputs found
The Minimal Length of a Lagrangian Cobordism between Legendrians
To investigate the rigidity and flexibility of Lagrangian cobordisms between
Legendrian submanifolds, we investigate the minimal length of such a cobordism,
which is a -dimensional measurement of the non-cylindrical portion of the
cobordism. Our primary tool is a set of real-valued capacities for a Legendrian
submanifold, which are derived from a filtered version of Legendrian Contact
Homology. Relationships between capacities of Legendrians at the ends of a
Lagrangian cobordism yield lower bounds on the length of the cobordism. We
apply the capacities to Lagrangian cobordisms realizing vertical dilations
(which may be arbitrarily short) and contractions (whose lengths are bounded
below). We also study the interaction between length and the linking of
multiple cobordisms as well as the lengths of cobordisms derived from
non-trivial loops of Legendrian isotopies.Comment: 33 pages, 9 figures. v2: Minor corrections in response to referee
comments. More general statement in Proposition 3.3 and some reorganization
at the end of Section
Erythrocyte antioxidant protection of rose hips (Rosa spp.)
Rose hips are popular in health promoting products as the fruits contain high content of bioactive compounds. The aim of this study was to investigate whether health benefits are attributable to ascorbic acid, phenols, or other rose-hip-derived compounds. Freeze-dried powder of rose hips was preextracted with metaphosphoric acid and the sample was then sequentially eluted on a C18 column. The degree of amelioration of oxidative damage was determined in an erythrocyte in vitro bioassay by comparing the effects of a reducing agent on erythrocytes alone or on erythrocytes pretreated with berry extracts. The maximum protection against oxidative stress, 59.4 ± 4.0% (mean standard deviation), was achieved when incubating the cells with the first eluted meta-phosphoric extract. Removal of ascorbic acid from this extract increased the protection against oxidative stress to 67.9 ± 1.9% . The protection from the 20% and 100% methanol extracts was 20.8 ± 8.2% and 5.0 ± 3.2% , respectively. Antioxidant uptake was confirmed by measurement of catechin by HPLC-ESI-MS in the 20% methanol extract. The fact that all sequentially eluted extracts studied contributed to protective effects on the erythrocytes indicates that rose hips contain a promising level of clinically relevant antioxidant protection
Importance of correlation effects in hcp iron revealed by a pressure-induced electronic topological transition
We discover that hcp phases of Fe and Fe0.9Ni0.1 undergo an electronic
topological transition at pressures of about 40 GPa. This topological change of
the Fermi surface manifests itself through anomalous behavior of the Debye
sound velocity, c/a lattice parameter ratio and M\"ossbauer center shift
observed in our experiments. First-principles simulations within the dynamic
mean field approach demonstrate that the transition is induced by many-electron
effects. It is absent in one-electron calculations and represents a clear
signature of correlation effects in hcp Fe
Linking and causality in globally hyperbolic spacetimes
The linking number is defined if link components are zero homologous.
Our affine linking invariant generalizes to the case of linked
submanifolds with arbitrary homology classes. We apply to the study of
causality in Lorentz manifolds. Let be a spacelike Cauchy surface in a
globally hyperbolic spacetime . The spherical cotangent bundle
is identified with the space of all null geodesics in
Hence the set of null geodesics passing through a point gives an
embedded -sphere in called the sky of Low observed
that if the link is nontrivial, then are causally
related. This motivated the problem (communicated by Penrose) on the Arnold's
1998 problem list to apply link theory to the study of causality. The spheres
are isotopic to fibers of They are nonzero
homologous and is undefined when is closed, while is well defined. Moreover, if is not an
odd-dimensional rational homology sphere. We give a formula for the increment
of \alk under passages through Arnold dangerous tangencies. If is
such that takes values in and is conformal to having all
the timelike sectional curvatures nonnegative, then are causally
related if and only if . We show that in
nonrefocussing are causally unrelated iff can be deformed
to a pair of -fibers of by an isotopy through skies. Low
showed that if (\ss, g) is refocussing, then is compact. We show that the
universal cover of is also compact.Comment: We added: Theorem 11.5 saying that a Cauchy surface in a refocussing
space time has finite pi_1; changed Theorem 7.5 to be in terms of conformal
classes of Lorentz metrics and did a few more changes. 45 pages, 3 figures. A
part of the paper (several results of sections 4,5,6,9,10) is an extension
and development of our work math.GT/0207219 in the context of Lorentzian
geometry. The results of sections 7,8,11,12 and Appendix B are ne
Parallel cyclin E and cyclin A expression in neoplastic lesions of the uterine cervix
Cyclin E levels are high during late G1 and early S-phase in normal cells. The cyclin E expression over the cell cycle in tumours is not fully known. The impact on patient outcome by high cyclin E levels during other parts of the cell cycle than late G1- and early S-phase is unknown. We set out to study the expression of cyclin E over the cell cycle in cervical carcinomas. Using immunofluorescence staining of cyclin A, digital microscopy, and digital image analysis, we determined which cells in a tissue section that were in S- or G2-phase. M-phase cells were detected by morphology. By simultaneously staining for cyclin E, we investigated the variation in cyclin E levels over the cell cycle in cervical carcinoma lesions. In a case–control study, in which each deceased patient was matched with a patient still alive and well after >5 years of follow-up, we found that the deceased patients had a considerably higher fraction of cyclin A-positive cells staining for cyclin E than the survivors (n=36). We conclude that parallel cyclin E and cyclin A expression is an indicator for poor outcome in cervical carcinomas. In addition, we investigated the expression pattern of cyclin E and cyclin A in consecutive biopsy samples from cervical carcinomas at different stages, as well as in human papillomavirus positive or negative adenocarcinomas in order to further study the cyclin E and cyclin A expression pattern in neoplastic lesions of the uterine cervix
The Hubble Space Telescope Key Project on the Extragalactic Distance Scale XXIV: The Calibration of Tully-Fisher Relations and the Value of the Hubble Constant
This paper presents the calibration of BVRIH$ Tully-Fisher relations based on
Cepheid distances to 21 galaxies within 25 Mpc, and 23 clusters within 10,000
km/s. These relations have been applied to several distant cluster surveys in
order to derive a value for the Hubble constant, H0, mainly concentrating on an
I-band all-sky survey by Giovanelli and collaborators which consisted of total
I magnitudes and 50% linewidth data for ~550 galaxies in 16 clusters. For
comparison, we also derive the values of H0 using surveys in B-band and V-band
by Bothun and collaborators, and in H-band by Aaronson and collaborators.
Careful comparisons with various other databases from literature suggest that
the H-band data, whose magnitudes are isophotal magnitudes extrapolated from
aperture magnitudes rather than total magnitudes, are subject to systematic
uncertainties. Taking a weighted average of the estimates of Hubble constants
from four surveys, we obtain H0 = 71 +- 4 (random) +- 7 (systematic) km/s/Mpc.
We have also investigated how various systematic uncertainties affect the value
of H0 such as the internal extinction correction method used, Tully-Fisher
slopes and shapes, a possible metallicity dependence of the Cepheid
period-luminosity relation and cluster population incompleteness bias.Comment: 34 pages, 13 figure
Nordic Innovative Trials to Evaluate osteoPorotic Fractures (NITEP) Collaboration: The Nordic DeltaCon Trial protocol-non-operative treatment versus reversed total shoulder arthroplasty in patients 65 years of age and older with a displaced proximal humerus fracture: a prospective, randomised controlled trial
Introduction The proximal humerus fracture (PHF) is one of the most common fractures in the elderly. The majority of PHFs are treated non-operatively, while 15%-33% of patients undergo surgical treatment. Recent randomised controlled trial (RCT) and meta-analyses have shown that there is no difference in outcome between non-operative treatment and locking plate or hemi-arthroplasty. During the past decade, reverse total shoulder arthroplasty (RTSA) has gained popularity in the treatment of PHF, although there is a lack of RCTs comparing RTSA to non-operative treatment.Methods This is a prospective, single-blinded, randomised, controlled, multicentre and multinational trial comparing RTSA with non-operative treatment in displaced proximal humeral fractures in patients 65-85 years. The primary outcome in this study is QuickDASH-score measured at 2 years. Secondary outcomes include visual analogue scale for pain, grip strength, Oxford shoulder score, Constant score and the number of reoperations and complications. The hypothesis of the trial is that operative treatment with RTSA produces better outcome after 2 and 5 years measured with QuickDASH.Ethics and dissemination In this protocol, we describe the design, method and management of the Nordic DeltaCon trial. The ethical approval for the trial has been given by the Regional Committee for Medical and Health Research Ethics, Norway. There have been several examples in orthopaedics of innovations that result in failure after medium-term follow-ups. In order to prevent such failures and to increase our knowledge of RSTA, we feel a large-scale study of the effects of the surgery on the outcome that focuses on the complications and reoperations is warranted. After the trial 2-year follow-up, the results will be disseminated in a major orthopaedic publication
Hardy's inequality for functions vanishing on a part of the boundary
We develop a geometric framework for Hardy's inequality on a bounded domain
when the functions do vanish only on a closed portion of the boundary.Comment: 26 pages, 2 figures, includes several improvements in Sections 6-8
allowing to relax the assumptions in the main results. Final version
published at http://link.springer.com/article/10.1007%2Fs11118-015-9463-
Fusion of secretory vesicles isolated from rat liver
Secretory vesicles isolated from rat liver were found to fuse after exposure to Ca2+. Vescle fusion is characterized by the occurrence of twinned vesicles with a continuous cleavage plane between two vesicles in freeze-fracture electron microscopy. The number of fused vesicles increases with increasing Ca2+-concentrations and is half maximal around 10–6 m. Other divalent cations (Ba2+, Sr2+, and Mg2+) were ineffective. Mg2+ inhibits Ca2+-induced fusion. Therefore, the fusion of secretory vesiclesin vitro is Ca2+ specific and exhibits properties similar to the exocytotic process of various secretory cells.
Various substances affecting secretionin vivo (microtubular inhibitors, local anethetics, ionophores) were tested for their effect on membrane fusion in our system.
The fusion of isolated secretory vesicles from liver was found to differ from that of pure phospholipid membranes in its temperature dependence, in its much lower requirement for Ca2+, and in its Ca2+-specificity. Chemical and enzymatic modifications of the vesicle membrane indicate that glycoproteins may account for these differences
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