275 research outputs found
Conţinutul şi componenţa uleiului esenţial la specii de Hypericum L. (sunătoare) din flora spontană a Republicii Moldova
Speciile genului Hypericum L. din flora spontană a Republicii Moldova se deosebesc
prin conţinutul şi componenţa uleiului esenţial obţinut prin hidrodistilare în aparate
Ginsberg din partea aeriană a plantei (Hyperici herba). H. perforatum conţine în herba
0.26% (s.u.) ulei esenţial, H. elegans – 0.15% (s.u.), H. hirsutum – 0.094% (s.u.) şi H.
tetrapterum - 0.13% (s.u.). Analiza GC-MS a uleiului esenţial a demonstrat deosebiri
substanţiale atât cantitative cât şi calitative. Numărul componenţilor identificaţi în uleiul
esenţial al diferitor specii de Hypericum este diferit. În uleiul esenţial separat din H. perforatum L. s-au identificaţi 33 componenţi, β-cariofilen şi cariofilen oxid în concentraţii
de peste 12% fiind componenţii majori, urmaţi de α-pinen (8.574%), β-cadinen (4.155%)
şi β-pinen (3.216). La H. elegans în uleiul esenţial au fost identificaţi 18 componenţi, ggurjunen, aromadendren şi undecan fiind componenţii majori în concentraţii de 14.532,
13.990 şi 10.262 %, respectiv. La specia H. tetrapterum s-au identificat în uleiul esenţial 21 componenţi, iar componenţii majori sunt copaen (9.271%), α-longipinen (8.489%)
urmaţi de cadinen (6.423%). În uleiul esenţial al speciei H. hirsutum au fost identificaţi
numai 9 componenţi, concentraţii mai ridicate fiind atestate la cariofilen oxid (10.435%),
phytol (6.056%), α-cariofilen (5.086) şi undecan (4.279)
Kripke Semantics and Proof Systems for Combining Intuitionistic Logic and Classical Logic
International audienceWe combine intuitionistic logic and classical logic into a new, first-order logic called Polarized Intuitionistic Logic. This logic is based on a distinction between two dual polarities which we call red and green to distinguish them from other forms of polarization. The meaning of these polarities is defined model-theoretically by a Kripke-style semantics for the logic. Two proof systems are also formulated. The first system extends Gentzen's intuitionistic sequent calculus LJ. In addition, this system also bears essential similarities to Girard's LC proof system for classical logic. The second proof system is based on a semantic tableau and extends Dragalin's multiple-conclusion version of intuitionistic sequent calculus. We show that soundness and completeness hold for these notions of semantics and proofs, from which it follows that cut is admissible in the proof systems and that the propositional fragment of the logic is decidable
Functional Uniform Priors for Nonlinear Modelling
This paper considers the topic of finding prior distributions when a major
component of the statistical model depends on a nonlinear function. Using
results on how to construct uniform distributions in general metric spaces, we
propose a prior distribution that is uniform in the space of functional shapes
of the underlying nonlinear function and then back-transform to obtain a prior
distribution for the original model parameters. The primary application
considered in this article is nonlinear regression, but the idea might be of
interest beyond this case. For nonlinear regression the so constructed priors
have the advantage that they are parametrization invariant and do not violate
the likelihood principle, as opposed to uniform distributions on the parameters
or the Jeffrey's prior, respectively. The utility of the proposed priors is
demonstrated in the context of nonlinear regression modelling in clinical
dose-finding trials, through a real data example and simulation. In addition
the proposed priors are used for calculation of an optimal Bayesian design.Comment: submitted for publicatio
Chemical Composition and Antimicrobial Activity of the Levisticum Officinale W.D.J. Koch Essential Oil
The chemical composition of industrially obtained Levisticum officinale W.D.J. Koch (lovage) essential oil of Moldovan origin was analysed by means of chromatographic (GC-MS) and spectral (IR, 1H and 13C NMR) methods. The obtained results show that the main components of L. officinale essential oil are monoterpenic hydrocarbons which make up to 53.50% of the total number of components. L. officinale essential oil is also characterized by a high content of oxygenated monoterpenes (alcohols, cetones and esters), which reaches up to 33.60%. For the first time the presence of 6-butyl-cyclohepta-1,4-diene (0.56%) and 7-formyl-4-methyl-cumarine (0.15%) in lovage essential oil is reported. Antibacterial and antifungal activities of mentioned oil were evaluated in vitro on five strains of microorganisms. It was found that lovage volatile oil (L .officinale) exhibits high antibacterial and antifungal properties in the range of concentrations 0.015-0.030%
Chromatographic Analysis of Silybum Marianum (L.) Gaertn. Fatty Oil
The present paper describes biochemical (fatty oil) composition of Silybummarianum (L.) Gaertn. of Moldovan origin. The oil content of the seeds was approximately 25%. Linoleic acid (C18:2), an essential polyunsaturated fatty acid, is the most abundant (48.88%), followed by monounsaturated oleic acid (C18:1, 31.94%) and saturated palmitic acid (C16:0, 7.61%). The RP-HPLC analysis of tocopherols composition, showed as main components α-tocopherol (23.45 mg/100g) and γ–tocopherol (5.60 mg/100g). Based on the obtained results, it was shown that the extracted oil from milk thistle seeds is rich in essential fatty acids (about 50%) and tocopherols (29.09 mg/100g) and it can be used in food preparation
Heyting-valued interpretations for Constructive Set Theory
We define and investigate Heyting-valued interpretations for Constructive Zermelo–Frankel set theory (CZF). These interpretations provide models for CZF that are analogous to Boolean-valued models for ZF and to Heyting-valued models for IZF. Heyting-valued interpretations are defined here using set-generated frames and formal topologies. As applications of Heyting-valued interpretations, we present a relative consistency result and an independence proof
Continuation-Passing Style and Strong Normalisation for Intuitionistic Sequent Calculi
The intuitionistic fragment of the call-by-name version of Curien and
Herbelin's \lambda\_mu\_{\~mu}-calculus is isolated and proved strongly
normalising by means of an embedding into the simply-typed lambda-calculus. Our
embedding is a continuation-and-garbage-passing style translation, the
inspiring idea coming from Ikeda and Nakazawa's translation of Parigot's
\lambda\_mu-calculus. The embedding strictly simulates reductions while usual
continuation-passing-style transformations erase permutative reduction steps.
For our intuitionistic sequent calculus, we even only need "units of garbage"
to be passed. We apply the same method to other calculi, namely successive
extensions of the simply-typed λ-calculus leading to our intuitionistic
system, and already for the simplest extension we consider (λ-calculus
with generalised application), this yields the first proof of strong
normalisation through a reduction-preserving embedding. The results obtained
extend to second and higher-order calculi
Adaptive Trial Design: Could We Use This Approach to Improve Clinical Trials in the Field of Global Health?
We need more clinical trials in the world's poorest regions to evaluate new drugs and vaccines, and also to find better ways to manage health issues. Clinical trials are expensive, time consuming, and cumbersome. However, in wealthier regions these limiting factors are being addressed to make trials less administrative and improve the designs. A good example is adaptive trial design. This innovation is becoming accepted by the regulators and has been taken up by the pharmaceutical industry to reduce product development times and costs. If this approach makes trials easier and less expensive surely we should be implementing this approach in the field of tropical medicine and international health? As yet this has rarely been proposed and there are few examples. There is a need for raising the awareness of these design approaches because they could be used to make dramatic improvements to clinical research in developing countries
Synthesis of New Homodrimane Sesquiterpenoids Containing Diazine, 1,2,4-triazole and Carbazole Rings
The study describes the synthesis of 11-homodrim-6,8-dien-12-oic acid N-substituted amides containing diazine, 1,2,4-triazole and carbazole rings based on commercially available sclareolide. The mentioned compounds were prepared for the first time by interaction of the generated in situ acyl chloride with some heterocyclic amines: 2- and 4-aminopyrimidine, 2-aminopyrazine, 3-amino-1,2,4-triazole and N-aminocarbazole. Their structures were fully elucidated by elemental and spectral analyses (IR, 1H and 13C NMR)
- …