A comparative study of overtone CH- stretching vibrational circular dichroism spectra of fenchone and camphor

Near-infrared vibrational circular dichroism (VCD) spectra in the region 1500-850 nm are recorded for both enantiomers of camphor and fenchone using a home-built dispersive instrument. Two CH-stretching overtone regions and two CH-stretching/HCH-bending combination regions are investigated. The near-infrared VCD data are examined and compared with the corresponding previously published data of (3R)-(+)-methylcyclopentanone and (3R)-(+)-methylcyclohexanone. The absorption spectra of both the fundamental and overtone regions are also considered, and the fundamental CH-stretching VCD data are taken into account, where possible. An empirical assignment of the spectra is first considered, with special regard to the second CHstretching overtone region. This region is then investigated by a heuristic approach based on DFT calculations, using the hybrid functional B3LYP at the 6-31G** basis set level. Subsequently rotational strengths have been evaluated by use of a classical model based on the contribution of polarizable groups to the optical activity. The same models are also used to interpret the VCD spectra between 2000 and 3000 wavenumbers for (3R)-(+)-methylcyclopentanone-d4

Prenatal Diagnosis of Gómez-López-Hernández Syndrome.

Gómez-López-Hernández syndrome (GLHS), also known as cerebello-trigeminal-dermal dysplasia, is an extremely rare neurocutaneous disease, classically described by the triad of rhombencephalosynapsis (RES), bilateral focal alopecia, and trigeminal anesthesia. The clinical and radiographic spectrum of GLHS is now known to be broader, including craniofacial and supratentorial anomalies, as well as neurodevelopmental issues. Here, we present a case of antenatally diagnosed GLHS with RES, hydrocephaly, and craniofacial anomalies identified on ultrasound (low-set ears with posterior rotation, hypertelorism, midface hypoplasia, micrognathia, and anteverted nares) which were confirmed by autopsy after termination of pregnancy at 23 weeks of gestation. As no known genetic causes have been identified and the classical triad is not applicable to prenatal imaging, prenatal diagnosis of GLHS is based on neuroimaging and the identification of supporting features. In presence of an RES associated with craniofacial abnormalities in prenatal (brachycephaly, turricephaly, low-set ears, midface retrusion, micrognathia), GLHS should be considered as "possible" according to postnatal criteria

Dynamic Ligand Discrimination in the Notch Signaling Pathway

The Notch signaling pathway comprises multiple ligands that are used in distinct biological contexts. In principle, different ligands could activate distinct target programs in signal-receiving cells, but it is unclear how such ligand discrimination could occur. Here, we show that cells use dynamics to discriminate signaling by the ligands Dll1 and Dll4 through the Notch1 receptor. Quantitative single-cell imaging revealed that Dll1 activates Notch1 in discrete, frequency-modulated pulses that specifically upregulate the Notch target gene Hes1. By contrast, Dll4 activates Notch1 in a sustained, amplitude-modulated manner that predominantly upregulates Hey1 and HeyL. Ectopic expression of Dll1 or Dll4 in chick neural crest produced opposite effects on myogenic differentiation, showing that ligand discrimination can occur in vivo. Finally, analysis of chimeric ligands suggests that ligand-receptor clustering underlies dynamic encoding of ligand identity. The ability of the pathway to utilize ligands as distinct communication channels has implications for diverse Notch-dependent processes

General Non-equilibrium Theory of Colloid Dynamics

A non-equilibrium extension of Onsager's canonical theory of thermal fluctuations is employed to derive a self-consistent theory for the description of the statistical properties of the instantaneous local concentration profile n(r,t) of a colloidal liquid in terms of the coupled time evolution equations of its mean value n(r,t) and of the covariance {\sigma}(r,r';t) \equiv of its fluctuations {\delta}n(r, t) = n(r, t) - n(r, t). These two coarse-grained equations involve a local mobility function b(r, t) which, in its turn, is written in terms of the memory function of the two-time correlation function C(r, r' ; t, t') \equiv <{\delta}n(r, t){\delta}n(r',t')>. For given effective interactions between colloidal particles and applied external fields, the resulting self-consistent theory is aimed at describing the evolution of a strongly correlated colloidal liquid from an initial state with arbitrary mean and covariance n^0(r) and {\sigma}^0(r,r') towards its equilibrium state characterized by the equilibrium local concentration profile n^(eq)(r) and equilibrium covariance {\sigma}^(eq)(r,r'). This theory also provides a general theoretical framework to describe irreversible processes associated with dynamic arrest transitions, such as aging, and the effects of spatial heterogeneities

Note sur une épizootie de mélioïdose porcine au Cambodge

cf. fichier PDF de l'article

Efficacy of fipronil/(S)-methoprene/eprinomectin/praziquantel (Broadline®) against Thelazia callipaeda in naturally infected cats

Background: The present clinical field trial was conducted to assess the efficacy of a broad-spectrum parasiticide spot-on formulation containing eprinomectin (Broadline®) against Thelazia callipaeda eyeworm in naturally infected cats. Methods: Fifteen privately owned cats harboring at least one live adult T. callipaeda were included in the study. Cats were randomly allocated to an untreated control group of seven cats or to a Broadline®-treated group of eight cats. Cats were treated on Day 0; ocular examinations were performed at inclusion and on Days 7 and 14; eyeworms were recovered and counted on Day 14. The primary efficacy assessment was based on group comparison of number of T. callipaeda on Day 14. Results: Seven days after treatment, six of eight treated cats were negative for eyeworm infection per visual examination, and on Day 14 no eyeworms were found in the treated cats while the seven untreated cats were still infected (geometric mean: 1.97). All cats had inflammatory ocular signs at inclusion; on Day 14, five of eight treated cats had recovered while all untreated control cats were still symptomatic. All collected parasites were confirmed to be T. callipaeda by morphology and molecular characterization. Conclusions: A single treatment with Broadline® provided 100% efficacy against feline thelaziosis and improved related ocular inflammation signs. Graphical abstract: [Figure not available: see fulltext.]

Encountering Latin American and Caribbean Feminisms

This article examines the Latin American and Caribbean Feminist Encuentros as critical transnational sites for the collective re-imagining of feminist politics in the region. Paying special attention to the most recent regional gathering, held in Juan Dolio, Dominican Republic in 1999, we analyze the major political and philosophical debates that have emerged during twenty years of Encuentros: 1) shifting conceptions of movement autonomy and feminisms\u27 relationship to the larger women\u27s movement and to other actors in civil and political society, the State, and international institutions; 2) controversies generated by the movements\u27 recurrent crises of inclusion and crises of expansion ; and 3) debates centered on differences, inequalities, and power imbalances among women, in general, and among feminists, in particular. While this essay explores how the Encuentros have marked feminist debates in the region, it also argues that they are, in themselves, productive transborder sites that not only reflect but also (re)shape Latin American and Caribbean feminist discourses and practices

Cis-interactions between Notch and Delta generate mutually exclusive signalling states

The Notch–Delta signalling pathway allows communication between neighbouring cells during development^1. It has a critical role in the formation of ‘fine-grained’ patterns, generating distinct cell fates among groups of initially equivalent neighbouring cells and sharply delineating neighbouring regions in developing tissues. The Delta ligand has been shown to have two activities: it transactivates Notch in neighbouring cells and cis-inhibits Notch in its own cell. However, it remains unclear how Notch integrates these two activities and how the resulting system facilitates pattern formation. Here we report the development of a quantitative time-lapse microscopy platform for analysing Notch–Delta signalling dynamics in individual mammalian cells, with the aim of addressing these issues. By controlling both cis- and trans-Delta concentrations, and monitoring the dynamics of a Notch reporter, we measured the combined cis–trans input–output relationship in the Notch–Delta system. The data revealed a striking difference between the responses of Notch to trans- and cis-Delta: whereas the response to trans-Delta is graded, the response to cis-Delta is sharp and occurs at a fixed threshold, independent of trans-Delta. We developed a simple mathematical model that shows how these behaviours emerge from the mutual inactivation of Notch and Delta proteins in the same cell. This interaction generates an ultrasensitive switch between mutually exclusive sending (high Delta/low Notch) and receiving (high Notch/low Delta) signalling states. At the multicellular level, this switch can amplify small differences between neighbouring cells even without transcription-mediated feedback. This Notch–Delta signalling switch facilitates the formation of sharp boundaries and lateral-inhibition patterns in models of development, and provides insight into previously unexplained mutant behaviours