Long‐Wavelength Fluorescent Reporters for Monitoring Protein Kinase Activity

In vivo optical imaging must contend with the limitations imposed by the optical window of tissue (600–1000 nm). Although a wide array of fluorophores are available that are visualized in the red and near‐IR region of the spectrum, with the exception of proteases, there are few long wavelength probes for enzymes. This situation poses a particular challenge for studying the intracellular biochemistry of erythrocytes, the high hemoglobin content of which optically obscures subcellular monitoring at wavelengths less than 600 nm. To address this, tunable fluorescent reporters for protein kinase activity were developed. The probing wavelength is preprogrammed by using readily available fluorophores, thereby enabling detection within the optical window of tissue, specifically in the far‐red and near‐IR region. These agents were used to monitor endogenous cAMP‐dependent protein kinase activity in erythrocyte lysates and in intact erythrocytes when using a light‐activatable reporter.     

Aspect-ratio dependent oscillatory thermocapillary convection in the floating half zone

The dependency of the critical Marangoni number on the geometrical aspect ratio of the floating half zone is essential to predict the onset of oscillatory thermocapillary convection.The experimental studies in the microgravity conditions on floating half zones of several centimeters in diameter have predicted that the critical Marangoni number increases with the increasing aspect ratio,and the terrestrial experimental studies have predicted the contradictory conclusion for floating half zones of several mil...     

Non-Gravitational Effects with Density-Matching in Evaluating the Influence of Sedimentation on Colloidal Coagulation

The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions in studies on dynamic behaviour of a colloidal system. However, the associated changes in the solvent composition may bring side effects to the properties investigated and therefore might lead to a faulty conclusion if the relevant correction is not made. To illustrate the importance of this side effect, we present an example of the sedimentation influence on the coagulation rate of suspensions of 2μm （diameter） polystyrene. The liquid mixtures, in the proper proportions of water （H2O）, deuterium oxide （D2O） and methanol （MeOH） as the liquid phase, density-matched and unmatched experiments are performed. Besides the influence of viscosity, the presence of methanol in solvent media, used to enhance the sedimentation effect, causes significant changes （reduction） in rapid coagulation rates compared to that in pure water. Without the relevant corrections for those non-gravitational factors it seems that gravitational sedimentation would retard the coagulation. The magnitude of the contribution from the non-gravitational factor is quantitatively determined, making the relevant correction possible. After necessary the influence of the sedimentation on coagulation rates at corrections for all factors, our experiments show that the initial stage of the coagulation is not observable.     

Spin squeezing and quantum correlations

We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among the spinors in the coupled state.     

Identification and composition of cuticular hydrocarbons of the major Afrotropical malaria vector Anopheles gambiae s.s. (Diptera: Culicidae): analysis of sexual dimorphism and age-related changes

Forty-eight cuticular hydrocarbons (CHCs) were characterized by gas chromatography-mass spectrometry from the epicuticular surface of the major Afrotropical malaria vector Anopheles gambiae. The hydrocarbons identified were 14 n-alkanes, 16 monomethyl alkanes, 13 dimethyl alkanes, 5 alkenes, with main-chain lengths ranging from C(17) to C(47), and the results are consistent with those from other Culicidae species. Qualitative differences were not observed between laboratory pools of three females and males, between different age-groups (0-16 days) and between single field specimens, whereas quantitative differences in CHC profiles were observed. Differences between sexes were more marked in individuals aged 0-2 days than in older ones. Both sexes undergo strong CHC profile changes with age, and individuals aged 0-2 days differ remarkably from the older ones. The possibility of exploiting these changes for estimating the age of mosquito was explored through multivariate analyses of the relative abundance of the compounds, using either the whole CHC profile or a subset of CHCs. Such a method allows us to assign more than 85% of females and 75% of males to the correct age-group. Although preliminary, these results show that the method is promising, as it has already been shown in Aedes aegypti and An. stephensi. The correct determination of the vector age (particularly in the case of the An. gambiae complex of sibling species) provides valuable information in malaria epidemiology and in evaluation of the effectiveness of vector control strategies. Further efforts will be made to validate this method on single specimens reared in seminatural conditions before being proposed to medical entomologists working in the Afrotropical region.