Anisotropic anharmonicity of lattice and molecular vibrations of 1,2,4,5 tetrabromobenzene determined by piezomodulated Raman spectroscopy

Strain-induced coupling constants for the anharmonicity of Raman-active lattice and certain molecular modes of vibration in 1,2,4,5-tetrabromobenzene (TBB) crystals have been determined using piezomodulated Raman spectroscopy. These constants, which are directly related to the first anharmonic term in the potential energy expansion for lattice dynamical calculations, are a quantitative measurement of the modal anharmonicities in the TBB molecular crystal. Application of uniaxial stress in the experiments permits the anisotropy of the anharmonicity to be determined as well as its magnitude. The TBB lattice modes are significantly coupled by the induced strains and the effects of coupling were observed to be dependent on the direction and symmetry of the strains. The molecular modes investigated were, by comparison, less coupled by the acoustic phonons and generally exhibited less anharmonic response with increasing frequency

Semiempirical determination of molecular motions associated with phonon modes in molecular crystals

An approach using piezomodulated Raman scattering is presented which permits determination of the molecular motions associated with the eigenmodes of molecular crystals. When coupled with a lattice dynamical calculation for the eigenmodes, the experiment can be used to validate the calculation. The case of 1,2,4,5-tetrabromobenzene is treated and it is shown that the phase relations of the piezomodulated Raman signals confirm the calculated eigenmodes. The Journal of Chemical Physics is copyrighted by The American Institute of Physics

Semiempirical determination of molecular motions associated with phonon modes in molecular crystals

An approach using piezomodulated Raman scattering is presented which permits determination of the molecular motions associated with the eigenmodes of molecular crystals. When coupled with a lattice dynamical calculation for the eigenmodes, the experiment can be used to validate the calculation. The case of 1,2,4,5-tetrabromobenzene is treated and it is shown that the phase relations of the piezomodulated Raman signals confirm the calculated eigenmodes. The Journal of Chemical Physics is copyrighted by The American Institute of Physics

Targeted protein delivery: carbodiimide crosslinking influences protein release from microparticles incorporated within collagen scaffolds

open access articleTissue engineering response may be tailored via controlled, sustained release of active agents from protein-loaded degradable microparticles incorporated directly within three-dimensional (3D) ice-templated collagen scaffolds. However, the effects of covalent crosslinking during scaffold preparation on the availability and release of protein from the incorporated microparticles have not been explored. Here, we load 3D ice-templated collagen scaffolds with controlled additions of poly-(DL-lactide-co-glycolide) microparticles. We probe the effects of subsequent N-(3-dimethylaminopropyl)- N0-ethylcarbodiimide hydrochloride crosslinking on protein release, using microparticles with different internal protein distributions. Fluorescein isothiocyanate labelled bovine serum albumin is used as a model protein drug. The scaffolds display a homogeneous microparticle distribution, and a reduction in pore size and percolation diameter with increased microparticle addition, although these values did not fall below those reported as necessary for cell invasion. The protein distribution within the microparticles, near the surface or more deeply located within the microparticles, was important in determining the release profile and effect of crosslinking, as the surface was affected by the carbodiimide crosslinking reaction applied to the scaffold. Crosslinking of microparticles with a high proportion of protein at the surface caused both a reduction and delay in protein release. Protein located within the bulk of the microparticles, was protected from the crosslinking reaction and no delay in the overall release profile was seen

Assignment of the lattice modes in TCNQ0 single crystals

A complete assignment of the six librational modes of the TCNQ0 crystal has been made employing both polarized Raman spectroscopic measurements and lattice dynamical calculations. Agreement between theory and experiment is good and modes at 40.5, 74.5, and 96 cm-1 are assigned as Ag active and those at 63, 75.5, and 104 cm-1 are Bg active. The lattice modes are found to be clearly separated from the molecular modes. The study emphasizes the importance of crystal optics and quality in the measurement of the polarized Raman spectra of biaxial crystals. The Journal of Chemical Physics is copyrighted by The American Institute of Physics

Calcium-dependent regulation of the cell cycle via a novel MAPK–NF-κB pathway in Swiss 3T3 cells

Nuclear factor kappa B (NF-κB) has been implicated in the regulation of cell proliferation and transformation. We investigated the role of the serum-induced intracellular calcium increase in the NF-κB–dependent cell cycle progression in Swiss 3T3 fibroblasts. Noninvasive photoactivation of a calcium chelator (Diazo-2) was used to specifically disrupt the transient rise in calcium induced by serum stimulation of starved Swiss 3T3 cells. The serum-induced intracellular calcium peak was essential for subsequent NF-κB activation (measured by real-time imaging of the dynamic p65 and IκBα fluorescent fusion proteins), cyclin D1 (CD1) promoter-directed transcription (measured by real-time luminescence imaging of CD1 promoter-directed firefly luciferase activity), and progression to cell division. We further showed that the serum-induced mitogen-activated protein kinase (MAPK) phosphorylation is calcium dependent. Inhibition of the MAPK- but not the PtdIns3K-dependent pathway inhibited NF-κB signaling, and further, CD1 transcription and cell cycle progression. These data suggest that a serum-dependent calcium signal regulates the cell cycle via a MAPK–NF-κB pathway in Swiss 3T3 cells

Non-Gaussian CMBR angular power spectra

In this paper we show how the prediction of CMBR angular power spectra $C_l$ in non-Gaussian theories is affected by a cosmic covariance problem, that is $(C_l,C_{l'})$ correlations impart features on any observed $C_l$ spectrum which are absent from the average $C^l$ spectrum. Therefore the average spectrum is rendered a bad observational prediction, and two new prediction strategies, better adjusted to these theories, are proposed. In one we search for hidden random indices conditional to which the theory is released from the correlations. Contact with experiment can then be made in the form of the conditional power spectra plus the random index distribution. In another approach we apply to the problem a principal component analysis. We discuss the effect of correlations on the predictivity of non-Gaussian theories. We finish by showing how correlations may be crucial in delineating the borderline between predictions made by non-Gaussian and Gaussian theories. In fact, in some particular theories, correlations may act as powerful non-Gaussianity indicators

Expression of recombinant human ceruloplasmin – an absolute requirement for splicing signals in the expression cassette

AbstractWe report the successful expression of recombinant human ceruloplasmin which was made possible by inclusion of splicing signals in the expression vector. Ceruloplasmin cDNA expressed from the vector pNUT in baby hamster kidney cells gave protein yields of 0.03 mg/l which increased to 15 mg/l with splicing signals present. The defect in expression from the intronless cDNA is due to complete retention of ceruloplasmin mRNA in cell nuclei. The block to cytoplasmic export is alleviated by splicing signals, allowing full expression of the mRNA

Late Eocene-Oligocene granulite facies garnet-sillimanite migmatites from the Mogok Metamorphic belt, Myanmar, and implications for timing of slip along the Sagaing Fault

MPS is grateful to the Oxford-Burma Aung San Suu Kyi trust for funding research and field visits to Mogok. U-Th-Pb geochronology was funded by UCSB and NSF grants EAR-1348003 and EAR-1551054 to BH.The Mogok Metamorphic Belt (MMB) in Myanmar is a polymetamorphic, mainly Paleogene granulite-uppermost amphibolite facies terrane consisting mainly of marbles and calc-silicates hosting spinel, ruby and sapphire. Jurassic charnockite-syenite intrusions, as well as Eocene-Miocene leucogranite intrusions are also present. Pelitic rocks are uncommon, and where present, have sillimanite, both as primary inclusions in garnet and as secondary Bt + Sil coronas around garnet. Core samples from the Kyi-Tauk-Pauk gold mine at Thabeikkiyin, north of Mandalay, are mostly Grt + Bt + Sill gneisses and migmatites with uncommon interbanded Opx + Grt + Bt gneisses. Pseudosection modelling suggests prograde garnet growth occurred by biotite-dehydration melting that reached peak P–T conditions of 870–970 °C and ~ 0.9 GPa, and was followed by garnet breakdown forming coarse retrograde Bt + Sil coronas. U[sbnd]Pb monazite data show an early high-grade granulite event at 43–32 Ma, and a later upper amphibolite sillimanite-grade event peaking at 23–20 Ma, with a change in monazite chemistry after c. 22 Ma that is consistent with fluid/(melt) interaction and garnet breakdown. Elevated Th/U ratios from ~35 to 22 Ma, and at ~18 Ma are compatible with melt influx at that time, timing that is similar to the age of the regional Kabaing leucogranite in the Mogok valley area. Our data show that peak granulite facies metamorphism along the Mogok Metamorphic belt was mainly Middle Eocene-Early Oligocene, with upper amphibolite facies metamorphism extending to earliest Miocene. The MMB is cut abruptly by the Sagaing fault, a large-scale dextral fault that extends from the Andaman Sea north to the East Himalayan syntaxis. Our new U[sbnd]Pb monazite data constrain the oldest age of initiation of the eastern branch of the cross-cutting Sagaing dextral strike-slip fault atPostprintPeer reviewe