522 research outputs found
Bis(3-methylphenolato-κO)(nitrosyl-κN)[tris(3,5-dimethylpyrazol-1-yl-κN 2)hydridoborato]molybdenum(II)
The title complex, [Mo(C15H22BN6)(C7H7O)2(NO)], contains an {MoNO}4 core stabilized by κ3-hydrotris(3,5-dimethylpyrazol-1-yl)borate, [TpMe2]−, and two anionic m-cresolate ligands, leading to a distorted octahedral geometry for the Mo atom. The short Mo—O bond lengths [1.935 (2) and 1.971 (2) Å], as well as large Mo—O—Csp
2 angles [134.2 (2) and 143.54 (19)°], indicate dπMo—pπO interactions, which are clearly weaker when compared with {Mo(NO)(TpMe2)} alkoxides. The nitrosyl system is virtually linear [179.3 (3)°] with Mo—N and N—O bond lengths of 1.760 (2) and 1.205 (3) Å, respectively. Intra- and intermolecular C—H(Ph or CH3)⋯π(Ph) interactions between adjacent phenyl rings are found in the crystal structure (d
H⋯Ph in the range 2.743–2.886 Å). One of the Ph rings shows disorder, i.e. swinging in the ring plane
Validation of differential pulse polarographic method of ascorbic acid assay in food – Comparison with the chromatographic reference method
The objective of the study was to demonstrate the applicability of differential pulse polarography (DPP) technique of the ascorbic acid (AA) assay for the analysis of food samples with various matrices. The following validation parameters were determined: selectivity, linearity, precision, accuracy, limit of detection, and limit of quantification. The limits of detection and quantification were 0.17 and 0.5 mg ascorbic acid per 100 g food, respectively. The average recovery of added ascorbic acid from all matrices was 96.3–103.6%. The values of the coefficient of variation calculated on the basis of AA contents for food matrices were in the range 2–9.26% and Horrat values were 0.37–1.10. Ascorbic acid values of the samples obtained from the polarographic method were compared with those obtained from high-performance liquid chromatography with diode-array detection (HPLC-DAD) used as the reference method. The analytical parameters determined showed that the polarographic method was equivalent to the chromatographic method. Validation of the polarographic method of ascorbic acid assay indicates that it can be applied for the analysis of ascorbic acid concentration in food products that do not contain isoascorbic acid. This means that the method can be recommended for routine determinations
Transverse momentum versus multiplicity fluctuations in high-energy nuclear collisions
We discuss recently measured event-by-event fluctuations of transverse
momentum and of multiplicity in relativistic heavy-ion collisions. It is shown
that the non-monotonic behavior of the p_T-fluctuations as a function of
collision centrality can be fully explained by the observed non-monotonic
multiplicity fluctuations. A possible mechanism responsible for the
multiplicity fluctuations is also considered.Comment: 5 pages, 3 figures, revised & extended, to appear in Phys. Rev.
Use of sweeteners in osmotic pretreatment before freeze-drying of pear and pineapple
The aim of the study was to analyse the influence of the type of osmotic substance (sucrose, glucose, xylitol, trehalose, and sorbitol) on the physicochemical properties of freeze-dried fruit (pear and pineapple). Controlling the functional properties of freeze-dried fruit after osmotic dehydration with aqueous solutions at water activity of a w=0.90 is presented. Decrease in the water adsorption index (WAI) was recorded for all dehydrated samples. The largest decrease (for pears and pineapples by 25 and 65%, respectively) was observed in osmoactive solutions containing trehalose. Considerable increase in the FAI was recorded in samples of dehydrated pineapple. In osmoactive trehalose solutions that increase hardly reached 46%, whereas in sorbitol and xylitol its value elevated to 39% and 13%, respectively. Regardless of the osmoactive sweetener applied prior to freeze-drying, an increase in specific surface area (SBET) of dried materials was observed. For dehydrated pears, SBET ranged from 96 to 697 m2 g−1, and for pineapple, from 115 to 938 m2 g−1. Osmotic dehydration before lyophilisation of fruit samples weakened rehydration relative to the control. The dehydration carried out with osmoactive sweeteners, that is, sorbitol, xylitol, and trehalose, allows obtaining a product with good functional properties that can be successfully used for supplementation of dietary products, in particular for diabetics
Single-Exponential FPT Algorithms for Enumerating Secluded -Free Subgraphs and Deleting to Scattered Graph Classes
The celebrated notion of important separators bounds the number of small
-separators in a graph which are 'farthest from ' in a technical
sense. In this paper, we introduce a generalization of this powerful
algorithmic primitive that is phrased in terms of -secluded vertex sets:
sets with an open neighborhood of size at most .
In this terminology, the bound on important separators says that there are at
most maximal -secluded connected vertex sets containing but
disjoint from . We generalize this statement significantly: even when we
demand that avoids a finite set of forbidden induced
subgraphs, the number of such maximal subgraphs is and they can be
enumerated efficiently. This allows us to make significant improvements for two
problems from the literature.
Our first application concerns the 'Connected -Secluded -free
subgraph' problem, where is a finite set of forbidden induced
subgraphs. Given a graph in which each vertex has a positive integer weight,
the problem asks to find a maximum-weight connected -secluded vertex set such that does not contain an induced subgraph
isomorphic to any . The parameterization by is known to
be solvable in triple-exponential time via the technique of recursive
understanding, which we improve to single-exponential.
Our second application concerns the deletion problem to scattered graph
classes. Here, the task is to find a vertex set of size at most whose
removal yields a graph whose each connected component belongs to one of the
prescribed graph classes . We obtain a single-exponential
algorithm whenever each class is characterized by a finite number of
forbidden induced subgraphs. This generalizes and improves upon earlier results
in the literature.Comment: To appear at ISAAC'2
Immunohistochemical characteristics of porcine intrahepatic nerves under physiological conditions and after bisphenol A administration
Background: The neurochemistry of hepatic nerve fibres was investigated in large animal models after dietary exposure to the endocrine disrupting compound known as bisphenol A (BPA).
Materials and methods: Antibodies against neuronal peptides were used to study changes in hepatic nerve fibres after exposure to BPA at varying concentrations using standard immunofluorescence techniques. The neuropeptides investigated were substance P (SP), galanin (GAL), pituitary adenylate cyclase activating polypeptide (PACAP), calcitonin gene regulated peptide (CGRP) and cocaine and amphetamine regulated transcript (CART). Immunoreactive nerve fibres were counted in multiple sections of the liver and among multiple animals at varying exposure levels. The data was pooled and presented as mean ± standard error of the mean.
Results: It was found that all of the nerve fibres investigated showed upregulation of these neural markers after BPA exposure, even at exposure levels currently considered to be safe. These results show very dramatic increases in nerve fibres containing the above-mentioned neuropeptides and the altered neurochemical levels may be causing a range of pathophysiological states if the trend of over-expression is extrapolated to developing humans.
Conclusions: This may have serious implications for children and young adults who are exposed to this very common plastic polymer, if the same trends are occurring in humans
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Printability study of metal ion crosslinked PEG-catechol based inks
In this paper we explore the printability of reversible networks formed by catechol functionalized PEG solutions and metal cations (Al3+, Fe3+ or V3+). The printability and shape fidelity were dependent on the ink composition (metal ion type, pH, PEG molecular weight) and printing parameters (extrusion pressure and printing speed). The relaxation time, recovery rate and viscosity of the inks were analyzed in rheology studies and correlated with thermodynamic and ligand exchange kinetic constants of the dynamic bonds and the printing performance (i.e. shape fidelity of the printed structures). The relevance of the relaxation time and ligand exchange kinetics for printability was demonstrated. Cells seeded on the materials crosslinked with Al3+, Fe3+ ions were viable and revealed well-spread morphologies during 7 day culture, indicating the potential of the formulations to be used as inks for cell encapsulation. The proposed dynamic ink design offers significant flexibility for 3D bioprinting, and enables straightforward adjustment of the printable formulation to meet application-specific needs
Inelaticity in hadron-nucleus collisions from emulsion chamber studies
The inelasticity of hadron-carbon nucleus collisions in the energy region
exceeding 100 TeV is estimated from the carbon-emulsion chamber data at Pamirs
to be . When combined with the recently presented data on
hadron-lead nucleus collisions taken at the same energy range it results in the
mass number dependence of inelasticity. The evaluated partial
inelasticity for secondary () interactions, ,
suggests that the second and higher interactions of the excited hadron inside
the nucleus proceed with only slight energy losses.Comment: LaTeX file and 5 LaTeX files with figures, 11 pages altogether.
Thoroughly rewritten and modified, one figure addded one removed. To be
published in Phys. Rev.
Endoscopic Obliteration for Bleeding Peptic Ulcer
A group of 133 patients treated for bleeding peptic ulcer in our Department, is reviewed.
Within several hours of admission, all patients underwent upper gastrointestinal tract
gastroscopy and obliteration of the bleeding ulcer. Bleeding gastric ulcers were found in
41 patients, and duodenal ulcers in 92 patients. Patients were classified according to the
Forrest scale: IA – 11 patients, IB – 49 patients, IIA – 35 patients, lIB – 40 patients.
In 126 (94.7%) patients the bleeding was stopped, and 7 required urgent surgery: 3
patients with gastric ulcer underwent gastrectomy, and 4 with duodenal ulcer – truncal
vagotomy with pyloroplasty and had the bleeding site underpinned. Fifty-five patients
underwent elective surgery: gastrectomy and vagotomy (18 patients with gastric ulcer),
highly selective vagotomy (25 patients with duodenal ulcer) and truncal vagotomy and
pyloroplasty (12 patients with duodenal ulcer). None of the patients was observed to
have recurrent bleeding
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