Search results for "Polarity"

When Predicates Behave Badly

2021

The main topics of this chapter are two: a discussion (at times very critical) of certain themes in Bolzano’s, Frege’s, and Wittgenstein’s work, and an analysis of some propositional attitudes. A new polarity correct–incorrect, distinct both from true–false, and from grammatical–ungrammatical, also begins to emerge.

Structural Approaches to Explain the Selectivity of COX-2 Inhibitors: Is There a Common Pharmacophore?

2000

The identification and characterisation of the isoenzyme cyclooxygenase 2 (COX-2) stimulated investigations to develop efficient non-steroidal anti-inflammatory drugs with reduced side effects compared to standard NSAIDs. This review will focus on the structural features needed to achieve COX-2 selectivity. Five structural classes can be identified together with a class bearing little or no resemblance to one another in their molecular structure. The most interesting point is the very distinct structure/activity relationship. On the one hand only minor modifications to a particular compound induce a drastic change in its COX selectivity and on the other hand the structural prerequisites in …

An Interlude: Matters of Method

2021

The discussion of everyday discourse developed so far makes two entirely new problems inescapable. The first is that in everyday discourse there is no algebra, either Boolean or non-Boolean, of truth values. The second is that a new polarity (conceptually) correct–incorrect, distinct both from true–false, and from grammatical–ungrammatical, becomes indispensable.

Dynamic electric field assisted multi-dimensional liquid chromatography of biological samples

2005

Complex biological samples require very high resolution separation strategies. The platform introduced here capitalises on the hyphenation of liquid chromatographic (LC) and electric potential gradient electrochromatographic multi-dimensional separation genres. First-dimension selectivity is provided by simultaneous size exclusion (SEC) and strong cation exchange (SCX) chromatography modes, while the second dimension comprises reversed phase (RP) characteristics in a dynamic (time-variant) electric field. The time-variant potential gradient with reversal of polarity is applied across the second dimension monolithic capillary throughout the duration of the solvent strength gradient elution. …

Subduction Polarity Reversal Triggered by Oceanic Plateau Accretion: Implications for Induced Subduction Initiation

2021

Drawback of ICA Procedure on EEG: Polarity Indeterminacy at Local Optimization

2008

Independent component analysis (ICA) has been extensively applied to reject artifacts in electroencephalography (EEG) signal processing. The first step is to extract the independent component activations from the electrode records, and then project the desired components back to the electrodes. After the composition of the projected component is analyzed in details under ICA procedure, this study shows that since ICA may extract some source components at the local optimization in high-dimensional EEG signal space, the artificial polarity indeterminacy may happen on the projected component at some electrodes. By numerical simulations, this issue also exhibits that this polarity ambiguity occ…

Polarity-reversal subduction zone initiation triggered by buoyant plateau obstruction

2022

Abstract Oceanic lithosphere worldwide is younger than ca. 200 Myr, suggesting that it must have been globally recycled by the recurrent formation of new subduction zones since the existence of subduction on Earth. However, postulated subduction zone initiation processes remain difficult to explain in many cases, and the specific geodynamic conditions under which these might occur are still largely unknown. We here use numerical models driven by the internal force balance of a subduction system to better understand the (geo)dynamics governing (intra-oceanic) polarity-reversal subduction zone initiation. This initiation mode assumes that the birth of a new subduction zone could be triggered …

Valence Topological Charge-Transfer Indices for Dipole Moments

2003

Valence topological charge-transfer (CT) indices are applied to the calculation of dipole moments. The dipole moments calculated by algebraic and vector semisums of the CT indices are defined. The combination of the CT indices allows the estimation of the dipole moments. The model is generalized for molecules with heteroatoms. The ability of the indices for the description of the molecular charge distribution is established by comparing them with the dipole moment of the valence-isoelectronic series of benzene and styrene. Two CT indices, μ v e c (vector semisum of vertex-pair dipole moments) and μ V v e c (valence μ v e c ) are proposed. μ v e c and μ V v e c are important for the predicti…

TALPID3 controls centrosome and cell polarity and the human ortholog KIAA0586 is mutated in Joubert syndrome (JBTS23)

2015

Joubert syndrome (JBTS) is a severe recessive neurodevelopmental ciliopathy which can affect several organ systems. Mutations in known JBTS genes account for approximately half of the cases. By homozygosity mapping and whole-exome sequencing, we identified a novel locus, JBTS23, with a homozygous splice site mutation in KIAA0586 (alias TALPID3), a known lethal ciliopathy locus in model organisms. Truncating KIAA0586 mutations were identified in two additional patients with JBTS. One mutation, c.428delG (p.Arg143Lysfs*4), is unexpectedly common in the general population and may be a major contributor to JBTS. We demonstrate KIAA0586 protein localization at the basal body in human and mouse p…

Vibrational dephasing of νs(OH) in 2,6-dichloro-4-nitrophenol

1988

Abstract A detailed analysis of the infrared bandshape of ν s (OH) in intramolecularly hydrogen-bonded 2,6-dichloro-4-nitrophenol in a series of solvents is presented. A distinct dependence of the bandshape and relaxation parameters on the polarity of solvent molecules has been found. The band shifts to lower wavenumbers, broadens and becomes more Gaussian with increasing solvent polarity; correspondingly, the correlation function decays faster and the correlation time decreases. The results are compared with those of previously studied systems. Factors determing the bandshape are discussed.