Biosynthesis and spectroscopic characterization of 2-TM fragments encompassing the sequence of a human GPCR, the Y4 receptor

This paper presents a divide‐and‐conquer approach towards obtaining solution structures of G protein‐coupled receptors. The human Y4 receptor was dissected into two to three transmembrane helix fragments, which were individually studied by solution NMR. We systematically compared various biosynthetic routes for the expression of the fragments in Escherichia coli and discuss purification strategies. In particular, we have compared the production of transmembrane (TM) fragments as inclusion bodies by using the ΔTrp leader sequence, with membrane‐directed expression by using Mistic as the fusion partner, and developed methods for enzymatic cleavage. In addition, direct expression of two‐TM fragments into inclusion bodies is a successful route in some cases. With the exception of TM13, we could produce all fragments in isotope‐labeled form in quantities sufficient for NMR studies. Almost complete backbone resonance assignment was obtained for the first two helices, as well as for helices 5 and 7, and a high degree was obtained for TM6, while conformational exchange processes resulted in the disappearance of many signals from TM4. In addition, complete assignments were obtained for all residues of the N‐terminal domain, as well as the extracellular and cytosolic loops (with the exception of an undecapeptide segment in the second extracellular loop, EC2) and for the complete cytosolic C‐terminal tail. In total, backbone resonances of 78 % of all residues were assigned for the Y4 receptor. Predictions of secondary structure based on backbone chemical shifts indicate that most residues from the TM regions adopt helical conformations, with exception of those around polar residues or prolines. However, the domain boundaries differ slightly from those predicted for homology models. We suggest that the obtained chemical shifts might be useful in assigning the full‐length receptor.     

Quantum Statistical Properties of Coupled Nonlinear Oscillators with Losses

Abstract

The statistical properties of two coupled nonlinear oscillators including losses are discussed using the statistics for the generalized superposition of coherent fields and quantum noise. Exact and approximate formulae for squeezing of vacuum fluctuations are derived. The photon statistics are shown to be Poissonian from the nonlinear dynamics of the lossless case. Non-classical behaviour is degraded by noise.     

Energy consumption feedback in perspective: integrating Australian data to meta-analyses on in-home displays

Providing homeowners with real-time feedback on their electricity consumption through a dedicated display device has been shown to reduce consumption by approximately 6–10 %. However, recent advances in smart grid technology have enabled larger sample sizes and more representative sample selection and recruitment methods for display trials. By analyzing these factors using data from current studies, this paper argues that a realistic, large-scale conservation effect from feedback is in the range of 3–5 %. Subsequent analysis shows that providing real-time feedback may not be a cost effective strategy for reducing carbon emissions in Australia, but that it may enable additional benefits such as customer retention and peak-load shift.     

Nanoparticle deposition effects on the minimum heat flux point and quench front speed during quenching in water-based alumina nanofluids

The quenching characteristics of metallic rodlets and spheres were investigated in pure water and water-based nanofluids with alumina nanoparticles of 0.1% by volume. The experiments were performed at both saturated and subcooled conditions under atmospheric pressure. The results demonstrate that while the initial quenching behavior in nanofluids is identical to that in pure water, both the minimum heat flux point temperature and quench front speed are significantly enhanced in subsequent quenching repetitions due to nanoparticle deposition. The nanoparticle effects on the quenching process were analyzed with focus on the intermittent liquid–solid contacts in the film boiling regime. It appears that the liquid–solid interaction during such short-lived contacts is more vigorous when a nanoparticle layer with improved surface wettability and roughness is present, which leads to the premature disruption of film boiling and quenching acceleration.     

Refractive Index Changes in CdSx Se1 − xdoped Glasses Through the Photodeflection Method

Abstract

Using the photo-deflection method in quasi c.w. regime refractive index variations of CdS_x Se_{1 ? x} doped glasses have been observed consisting of two independent contributions Δn = Δn_t + Δn_e. The photothermal term Δn_t = (dn/dT) ΔT (ΔT is the temperature increase) is positive and slow in time, the electronic term Δn_e is negative and fast. The electronic term appears at first due to a reversible contribution (during a time scale of 1/ω, where ω is the chopper frequency) and after a time of a few tenths of seconds disappears irreversibly. It is attributed to a redistribution in space and energy levels of electrons in the semiconductor microcrystals. This redistribution is large enough when the electron relaxation is not too fast. The consequent refractive index change decreases in time and disappears under prolonged laser irradiation. A model is presented in which the presence of traps is taken into account.     

Diffraction of a pulsed plane wave from an amplitude diffraction grating

Abstract

A study of diffraction of a time Gaussian-shaped pulse from an amplitude diffraction grating is presented. The changes of the spectral composition, time intensity and energy of the diffraction pattern are considered. The measurement of the spectral composition of the primary pulse with the help of a diffraction grating based on the measurement of the spatial distribution of energy of the diffraction pattern is discussed.     

Functionalized Fe‐Filled Multiwalled Carbon Nanotubes as Multifunctional Scaffolds for Magnetization of Cancer Cells

With the aim to design addressable magnetically‐active carbon nanotubes (CNTs) for cancer treatment, the use of Fe‐filled CNTs (Fe@MWCNTs) as multifunctional scaffolds is reported for exohedrally anchoring a monoclonal antibody (mAb) known to bind a plasma membrane receptor over‐expressed in several cancer cells (EGFR). Comprehensive microscopic (transmission electron microscopy, atomic force microscopy, and scanning electron microscopy) and spectroscopic (Raman, ⁵⁷Fe Mossbauer, energy dispersive spectroscopy, X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction) characterizations reveal the efficient confinement of magnetically‐active Fe phases (α‐Fe and Fe₃C), while compositional evaluations through XPS, thermogravimetric analysis and gel electrophoresis confirm that mAb immobilization onto Fe@MWCNTs occurs. Enzyme‐linked immunosorbent assay (ELISA), confocal microscopy imaging and western blotting confirm the targeting action toward EGFR‐overexpressing cell lines (EGFR+). In vitro magnetic filtration experiments demonstrate that a selective removal of EGFR+ cells from a mixed population of healthy cell lines could be obtained in very short times (≈10 min). Cytotoxicity evaluations by classic cell staining procedures after application of an electromagnetic radiation inducing magnetic fluid hyperthermia (MFH), show a selective suppression of the EGFR+ cell line. Molecular dynamics and docking simulations of the hybrid mAb/Fe@MWCNTs conjugates nicely show how the presence of the CNT framework does not sterically affect the conformational properties of the two antigen binding regions, further supporting the biochemical findings.     

Multiple-project discount rates for cost-benefit analysis in construction projects: a formal risk model for microgeneration renewable energy technologies

The traditional economic approach for appraising the costs and benefits of construction project net present values involves the calculation of net returns for each investment option under different discount rates. An alternative approach consists of multiple-project discount rates based on risk modelling. The example of a portfolio of microgeneration renewable energy technology is presented to demonstrate that risks and future available budget for re-investment can be taken into account when setting discount rates for construction project specifications in the presence of uncertainty. A formal demonstration is carried out through a reversed intertemporal approach of applied general equilibrium. It is demonstrated that risk and the estimated available budget for future re-investment can be included in the simultaneous assessment of the costs and benefits of multiple projects.