199 research outputs found
Eocene flora and trace fossils from the Hruby Regiel section in the Tatra Mountains (Poland) : taxonomic revision of the Wiktor Kuźniar fossil plant collection
No full textLatest Eocene plant macrofossils and trace fossils collected a century ago by Wiktor Kuźniar are revised and their stratigraphical and palaeoecological meaning is re-considered. They derive from marine limestones and marls cropping out on the northern slope of the Hruby Regiel mountain in the Western Tatra Mountains. Leaves belonging to the families Fagaceae and Lauraceae and fruits of the palm Nypa are recognized. The co-occurrence of the planktonic foraminifer taxa Chiloguembelina cf. gracillima and Globigerinatheca cf. index and fruits of Nypa suggests a latest Eocene age of the fossil flora. The plant assemblage is typical of paratropical or subtropical evergreen forests in a warm and humid subtropical climate, recent counterparts of which occur in southeast Asia. The presence of Nypa is characteristic of mangroves. The good state of preservation of the leaves suggests coastline proximity during sedimentation of the plant-bearing deposits
Synthesis of Stable and Potent d/m Opioid Peptides: Analogues of H-Tyr-c[D-Cys-Gly-Phe-D-Cys]-OH by Ring-Closing Metathesis.
No full textRing-closing metathesis has emerged as a powerful tool in organic synthesis for generating cyclic structures via C−C double bond formation. Recently, it has been successfully used in peptide chemistry for obtaining cyclic molecules bridged through an olefin unit in place of the usual disulfide bond. Here, we describe this approach for obtaining cyclic olefin bridged analogues of H-Tyr-c[d-Cys-Gly-Phe-Cys]-OH. The synthesis of the new ligands was performed using the second generation Grubbs' catalyst. The resulting cis-8 (cDADAE) and trans-9 (tDADAE) were fully characterized and tested at δ, μ, and κ opioid receptors. Also the linear precursor 13 (lDADAE) and the hydrogenated derivative 11 (rDADAE) also were tested. All the cyclic products containing a olefinic bond are slightly selective but highly active and potent for the δ and μ opioid receptors. Activity toward the κ opioid receptors was absent or very low
Enterprise planning model using REA ontology
No full textThe aim of the paper is to describe using REA framework to model enterprise planning not only at the operational level but also at the policy level. Using policy level enlarges the possibility of the models on the base of the REA framework because the policy level in this way represents metalevel of the model. The policy level of the REA framework itself is comprised of both the typification and grouping semantic abstractions and the Commitment entity. This entity may be viewed as either a sublayer or a middle layer of the REA framework. The Commitment entity belongs to the fundamental entities of the policy level but has some specifications that are expressed by the fulfillment relationship. This many-to-many relationship forms the link to the operational level. The paper thinks over the problem and suggests some solution that gets the Commitment entity closer to the typification semantic abstraction.REA framework; policy level; production planning model; typification; grouping; cardinality
Synthesis and activity of endomorphin-2 and morphiceptin analogues with proline surrogates in position 2
No full textTheopioidagonistsendomorphins(TyreProeTrpePheeNH2;EM1andTyreProePheePheeNH2;EM2)
andmorphiceptin(TyreProePheeProeNH2)exhibitanextremelyhighselectivityfor m-opioidreceptor.
HereaseriesofnovelEM2andmorphiceptinanaloguescontaininginplaceoftheprolineatposition2
the S and R residuesof b-homologuesofproline(HPro),of2-pyrrolidinemethanesulphonicacid(HPrs)
andof3-pyrrolidinesulphonicacid(bPrs)havebeensynthesizedandtheirbindingaffinityandfunctional
activityhavebeeninvestigated.Thehighest m-receptoraffinityisshownby[(S)bPrs
2
]EM2analogue(6e)
whichrepresentsthe firstexampleofa b-sulphonamidoanalogueinthe fieldofopioidpeptides
Diamond as a quantum sensor for space exploration
No full textSensing devices used in (aero)space are constrained by energy consumption, mass, volume and environmental
compatibility. Although quantum sensors offer potentially better sensitivity than classical sensors, they are bulky and
often require cooling to cryogenic temperatures or operation in vacuum. Here we propose a technical realization of a
quantum sensor for magnetic field detection based on nitrogen-vacancy (NV) centers in diamond, which is compatible
with miniaturization and offers potential sub-picotesla sensitivity. The miniaturization is based on recently developed
electric readout of the NV center electron spin resonance. Our engineering platform allows to use diamond chip as a
portable magnetic field sensor. We have designed and tested a miniaturized prototype and describe all key components
for technical miniaturization. We achieved a power consumption down to 3.5 W, a weight of the fully integrated sensor
of only 27g and small dimensions of 45 x 25 x 25 mm including all driving and readout components. We have proved
the chip functionality in vacuum and explored its thermal behavior. The system will be further used for on-board
stratospheric balloon experiment. The miniaturized sensor we developed has potential applications in a wide range of
fields including navigation, bio-signal measurement, material analysis or space weather monitoring and planetary
observation.FWO; FWO-SBO - DIAQUANT
The cis-4-amino-l-proline residue as a scaffold for the synthesis of cyclic and linear endomorphin-2 analogues
No full textEndomorphin-2 (EM-2: Tyr-Pro-Phe-Phe-NH 2) is an endogenous tetrapeptide that combines potency and efficacy with high affinity and selectivity toward the μ opioid receptor, the most responsible for analgesic effects in the central nervous system. The presence of the Pro 2 represents a crucial factor for the ligand structural and conformational properties. Proline is in fact an efficient stereochemical spacer, capable of inducing favorable spatial orientation of aromatic rings, a key factor for ligand recognition and interaction with receptors. Here the Pro 2 has been replaced by 4(S)-NH 2-2(S)-proline (cAmp), a proline/GABA cis-chimera residue. This bivalent amino acid maintains the capacity to influenc the tetrapeptide conformation and offers the opportunity to generate new linear models and unusually constrained cyclic analogues characterized by an N-terminal Tyr bearing a free N-alpha-amino group. The results indicate that the new analogues do not show affinity for both δ and κ opioid receptors and bind only poorly to the μ receptors (for cyclopeptide 9: K i μ = 660 nM; GPI (IC 50) = 1.4% at 1 μM; for linear tetrapeptide acid 13: K i μ = 2000 nM; GPI (IC 50) = 0% at 1 μM; for linear tetrapeptide amide 15: K i μ = 310 nM; GPI (IC 50) = 894 nM). © 2012 American Chemical Society
Diamond as a quantum sensor for space exploration
No full textSensing devices used in (aero)space are constrained by energy consumption, mass, volume and environmental
compatibility. Although quantum sensors offer potentially better sensitivity than classical sensors, they are bulky and
often require cooling to cryogenic temperatures or operation in vacuum. Here we propose a technical realization of a
quantum sensor for magnetic field detection based on nitrogen-vacancy (NV) centers in diamond, which is compatible
with miniaturization and offers potential sub-picotesla sensitivity. The miniaturization is based on recently developed
electric readout of the NV center electron spin resonance. Our engineering platform allows to use diamond chip as a
portable magnetic field sensor. We have designed and tested a miniaturized prototype and describe all key components
for technical miniaturization. We achieved a power consumption down to 3.5 W, a weight of the fully integrated sensor
of only 27g and small dimensions of 45 x 25 x 25 mm including all driving and readout components. We have proved
the chip functionality in vacuum and explored its thermal behavior. The system will be further used for on-board
stratospheric balloon experiment. The miniaturized sensor we developed has potential applications in a wide range of
fields including navigation, bio-signal measurement, material analysis or space weather monitoring and planetary
observation.FWO; FWO-SBO - DIAQUANT
Synthesis and evaluation of new endomorphin-2 analogues containing (Z)-α,β-didehydrophenylalanine (δZPhe) residues
No full textNew endomorphin-2 (EM-2) analogues incorporating (Z)-α,β- didehydrophenylalanine (δZPhe) in place of the native phenylalanine in EM-2 are reported. Tyr-Pro-δZPhe-Phe-NH 2 {[δZPhe3]EM-2} (1), Tyr-Pro-Phe-δZPhe-NH2 {[δZPhe 4]EM-2} (2), and Tyr-Pro-δZPhe- δZPhe-NH2 {[δZPhe 3,4]EM-2}(3) have been synthesized, their opioid receptor binding affinities and tissue bioassay activities were determined, and their conformational properties were examined. Compound 2 shows high μ opioid receptor selectivity and μ agonist activity comparable to those of the native peptide. The conformation adopted in solution and in the crystal by N-Boc-Tyr-Pro-δZPhe-Phe-NH2 (8) is reported. © 2010 American Chemical Society
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