1,358 research outputs found
Enumeration of Hypermaps of a Given Genus
This paper addresses the enumeration of rooted and unrooted hypermaps of a
given genus. For rooted hypermaps the enumeration method consists of
considering the more general family of multirooted hypermaps, in which darts
other than the root dart are distinguished. We give functional equations for
the generating series counting multirooted hypermaps of a given genus by number
of darts, vertices, edges, faces and the degrees of the vertices containing the
distinguished darts. We solve these equations to get parametric expressions of
the generating functions of rooted hypermaps of low genus. We also count
unrooted hypermaps of given genus by number of darts, vertices, hyperedges and
faces.Comment: 42 page
Limited proteolysis in the investigation of beta2-microglobulin amyloidogenic and fibrillar states.
Amyloid fibrils of patients treated with regular haemodialysis essentially consists of β2-microglobulin (β2-m) and its truncated species ΔN6β2-m lacking six residues at the amino terminus. The truncated fragment shows a higher propensity to self-aggregate and constitutes an excellent candidate for the analysis of a protein in the amyloidogenic conformation. The surface topology and the conformational analysis of native β2-m and the truncated ΔN6β2-m species both in the soluble and in the fibrillar forms were investigated by the limited proteolysis/mass spectrometry strategy. The conformation in solution of a further truncated mutant ΔN3β2-m lacking three residues at the N-terminus was also examined. This approach appeared particularly suited to investigate the regions that are solvent-exposed, or flexible enough to be accessible to protein-protein interactions and to describe the conformation of transient intermediates. Moreover, proteolysis experiments can also be tailored to investigate amyloid fibrils by discriminating the protein regions constituting the unaccessible core of the fibrils and those still flexible and exposed to the solvent. Although native β2-m and ΔN3β2-m shared essentially the same conformation, significative structural differences exist between the native and the ΔN6β2-m proteins in solution with major differences located at the end moiety of strand V and subsequent loop with strand VI and at both the N- and C-termini of the proteins. On the contrary, an identical distribution of preferential proteolytic sites was observed in both proteins in the fibrillar state, which was nearly superimposible to that observed for the soluble form of ΔN6β2-m. These data revealed that synthetic fibrils essentially consists of an unaccessible core comprising residues 20-87 of the β2-m protein with exposed and flexible N- and C-terminal ends. Moreover, proteolytic cleavages observed in vitro at Lys 6 and Lys 19 reproduce specific cleavages that have to take place in vivo to generate the truncated forms of β2-m occurring in natural fibrils. On the basis of these results, a molecular mechanism for fibril formation has been propose
Synthetic cathinones related fatalities: an update
Synthetic cathinones, more commonly known as "bath salts", are synthetic drugs chemically related to cathinone, a psychostimulant found in the khat plant. They are the first most consumed products among new psychoactive substances, which cause psychostimulant and hallucinogenic effects determining a number of fatalities worldwide. In this paper, we have systematically reviewed cases of synthetic cathinones-related fatalities analytically confirmed, which have occurred in the last few years.OBJECTIVE: Synthetic cathinones,
more commonly known as “bath salts”, are synthetic
drugs chemically related to cathinone, a
psychostimulant found in the khat plant. They are
the first most consumed products among new
psychoactive substances, which cause psychostimulant
and hallucinogenic effects determining
a number of fatalities worldwide. In this paper, we
have systematically reviewed cases of synthetic
cathinones-related fatalities analytically confirmed,
which have occurred in the last few years.
MATERIALS AND METHODS: Relevant scientific
articles were identified in Medline, Cochrane
Central, Scopus, Web of Science and Institutional/
government websites up to November 2017
using the following keywords: synthetic cathinones,
mephedrone, methylenedioxypyrovalerone,
MDPV, methylone, ethylone, buthylone, fatal
intoxication, fatalities and death.
RESULTS: In total, 20 citations met the criteria
for inclusion, representing several fatal cases
with analytically confirmed synthetic cathinones
in biological sample/s of the deceased. The
death was attributed to hyperthermia, hypertension,
cardiac arrest and more in general to the
classic serotonin syndrome. Only rarely did the
concentration of the parent drug causing fatality
overcome the value of 1 mg/L in post-mortem
biological fluids.
CONCLUSIONS: Abuse of synthetic cathinones
still represents a serious public health issue.
Systematic clinical studies on both the animal
and human model are lacking; therefore, the
only available data are from the users who experience
the possible hazardous consequences.
Analytical methodologies for the identification
of parent compounds and eventual metabolites
both in ante-mortem and post-mortem cases
need to be developed and validated. Analytical
data should be shared through different communication
platforms with the aim of stopping this
serious health threat for drug users
Matter waves in a gravitational field: An index of refraction for massive particles in general relativity
We consider the propagation of massive-particle de Broglie waves in a static,
isotropic metric in general relativity. We demonstrate the existence of an
index of refraction that governs the waves and that has all the properties of a
classical index of refraction. We confirm our interpretation with a WKB
solution of the general-relativistic Klein-Gordon equation. Finally, we make
some observations on the significance of the optical action.Comment: 20 pages, latex, ps and pdf. To appear in Am.J.Phys September, 200
Exact analysis of weighted centroid localization
Source localization of primary users (PUs) is a geolocation spectrum awareness feature that can be very useful in enhancing the functionality of cognitive radios (CRs). When the cooperating CRs have limited information about the PU, weighted centroid localization (WCL) based on received signal strength (RSS) measurements represents an attractive low-complexity
solution. In this paper, we propose a new analytical framework to calculate the exact performance of WCL in the presence of shadowing, based on results of the ratio of two quadratic forms in normal variables. In particular, we derive an exact expression for the root mean square error (RMSE) of the two-dimensional location estimate. Numerical results confirm that the derived framework is able to predict the performance of WCL capturing
all the essential aspects of propagation as well as CR network spatial topology
Influence of seed coat color on germination rate and seedling development of Trifolium repens. Is physiological dormancy possible?
Trifolium repens L. (var. Regal Ladino) is among the most used species of Italian legumes as fodder
for pastures, for direct consumption, or as mowing for stocks and then pastures. The seed
integument of Trifolium repens L. has different colors ranging from light yellow to dark brown. In
this work, the physiology of germination of light-colored, light intermediate, dark and dark
intermediate seeds was studied to highlight any difference in the percentage of seed germination
and seedling development. The results showed a lower germination rate and a noticeable reduction
of the root length in dark seeds compared to light seeds. In this context, tests to exclude a
physiological dormancy of dark seeds were performed. Light microscope and scanning electron
microscope observation were conducted to detect substantial differences in the structure and
thickness of the integument and in the quality of reserves. Biochemical investigations have
evidenced that total polyphenols content is similar in all the seeds categories, while higher amount
of total flavonoids was detected in dark seeds. Total Polyphenols and flavonoids content decreased
during germination in all seed groups
Galois Correspondence and Fourier Analysis on Local Discrete Subfactors
Discrete subfactors include a particular class of infinite index subfactors and all finite index ones. A discrete subfactor is called local when it is braided and it fulfills a commutativity condition motivated by the study of inclusion of Quantum Field Theories in the algebraic Haag–Kastler setting. In Bischoff et al. (J Funct Anal 281(1):109004, 2021), we proved that every irreducible local discrete subfactor arises as the fixed point subfactor under the action of a canonical compact hypergroup. In this work, we prove a Galois correspondence between intermediate von Neumann algebras and closed subhypergroups, and we study the subfactor theoretical Fourier transform in this context. Along the way, we extend the main results concerning α-induction and σ-restriction for braided subfactors previously known in the finite index case
40 MHz Scouting for the CMS Level-1 Trigger
The Level-1 trigger Data Scouting (L1DS) is a novel data acquisition system under development for the Phase-2 CMS detector at the High-Luminosity LHC (HL-LHC). Its purpose is to capture and process Level-1 trigger (L1T) information at the bunch crossing collision frequency of the LHC preceding the standard L1T selections. Referred to as 40 MHz Scouting, this system has the potential for filterless diagnostics for the detector, luminosity studies and investigations into
signatures and processes that would be otherwise inaccessible or constrained due to the bias introduced by the trigger. An outline of Phase-2 L1DS is provided alongside a description of the Run-3 demonstrator’s architecture and the preliminary results obtained
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