Boron isotope record of peak metamorphic ultrahigh-pressure and retrograde fluid–rock interaction in white mica (Lago di Cignana, Western Alps)

This study presents boron (B) concentration and isotope data for white mica from (ultra)high-pressure (UHP), subduction-related metamorphic rocks from Lago di Cignana (Western Alps, Italy). These rocks are of specific geological interest, because they comprise the most deeply subducted rocks of oceanic origin worldwide. Boron geochemistry can track fluid–rock interaction during their metamorphic evolution and provide important insights into mass transfer processes in subduction zones. The highest B contents (up to 345 μg/g B) occur in peak metamorphic phengite from a garnet–phengite quartzite. The B isotopic composition is variable (δ11B = − 10.3 to − 3.6%) and correlates positively with B concentrations. Based on similar textures and major element mica composition, neither textural differences, prograde growth zoning, diffusion nor a retrograde overprint can explain this correlation. Modelling shows that B devolatilization during metamorphism can explain the general trend, but fails to account for the wide compositional and isotopic variability in a single, well-equilibrated sample. We, therefore, argue that this trend represents fluid–rock interaction during peak metamorphic conditions. This interpretation is supported by fluid–rock interaction modelling of boron leaching and boron addition that can successfully reproduce the observed spread in δ11B and [B]. Taking into account the local availability of serpentinites as potential source rocks of the fluids, the temperatures reached during peak metamorphism that allow for serpentine dehydration, and the high positive δ11B values (δ11B = 20 ± 5) modelled for the fluids, an influx of serpentinite-derived fluid appears likely. Paragonite in lawsonite pseudomorphs in an eclogite and phengite from a retrogressed metabasite have B contents between 12 and 68 μg/g and δ11B values that cluster around 0% (δ11B = − 5.0 to + 3.5). White mica in both samples is related to distinct stages of retrograde metamorphism during exhumation of the rocks. The variable B geochemistry can be successfully modelled as fluid–rock interaction with low-to-moderate (< 3) fluid/rock ratios, where mica equilibrates with a fluid into which B preferentially partitions, causing leaching of B from the rock. The metamorphic rocks from Lago di Cignana show variable retention of B in white mica during subduction-related metamorphism and exhumation. The variability in the B geochemical signature in white mica is significant and enhances our understanding of metamorphic processes and their role in element transfer in subduction zones

Perturbative calculation of the scaled factorial moments in second-order quark-hadron phase transition within the Ginzburg-Landau description

The scaled factorial moments $F_q$ are studied for a second-order quark-hadron phase transition within the Ginzburg-Landau description. The role played by the ground state of the system under low temperature is emphasized. After a local shift of the order parameter the fluctuations are around the ground state, and a perturbative calculation for $F_q$ can be carried out. Power scaling between $F_q$'s is shown, and a universal scaling exponent $\nu\simeq 1.75$ is given for the case with weak correlations and weak self-interactions.Comment: 12 pages in RevTeX, 12 eps figure

Studies of the horizontal inhomogeneities in NO2 concentrations above a shipping lane using ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements and validation with airborne imaging DOAS measurements

This study describes a novel application of an “onion-peeling” approach to multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of shipping emissions aiming at investigating the strong horizontal inhomogeneities in NO2 over a shipping lane. To monitor ship emissions on the main shipping route towards the port of Hamburg, a two-channel (UV and visible) MAX-DOAS instrument was deployed on the island Neuwerk in the German Bight, 6–7 km south of the main shipping lane. Utilizing the fact that the effective light path length in the atmosphere depends systematically on wavelength, simultaneous measurements and DOAS retrievals in the UV and visible spectral ranges are used to probe air masses at different horizontal distances to the instrument to estimate two-dimensional pollutant distributions. Two case studies have been selected to demonstrate the ability to derive the approximate plume positions in the observed area. A situation with northerly wind shows high NO2 concentrations close to the measurement site and low values in the north of the shipping lane. The opposite situation with southerly wind, unfavorable for the on-site in situ instrumentation, demonstrates the ability to detect enhanced NO2 concentrations several kilometers away from the instrument. Using a Gaussian plume model, in-plume NO2 volume mixing ratios can be derived from the MAX-DOAS measurements. For validation, a comparison to airborne imaging DOAS measurements during the NOSE campaign in July 2013 is performed, showing good agreement between the approximate plume position derived from the onion-peeling MAX-DOAS and the airborne measurements as well as between the derived in-plume NO2 volume mixing ratios (VMRs)

Scaling of thermal conductivity of helium confined in pores

We have studied the thermal conductivity of confined superfluids on a bar-like geometry. We use the planar magnet lattice model on a lattice $H\times H\times L$ with $L \gg H$. We have applied open boundary conditions on the bar sides (the confined directions of length $H$) and periodic along the long direction. We have adopted a hybrid Monte Carlo algorithm to efficiently deal with the critical slowing down and in order to solve the dynamical equations of motion we use a discretization technique which introduces errors only $O((\delta t)^6)$ in the time step $\delta t$. Our results demonstrate the validity of scaling using known values of the critical exponents and we obtained the scaling function of the thermal resistivity. We find that our results for the thermal resistivity scaling function are in very good agreement with the available experimental results for pores using the tempComment: 5 two-column pages, 3 figures, Revtex

Evading innate immunity in nonviral mRNA delivery : don't shoot the messenger

In de field of non-viral gene therapy, in vitro transcribed (IVT) mRNA has emerged as a promising tool for the delivery of genetic information. Over the past few years it has become widely known the introduction of IVT mRNA into mammalian cells elicits an innate immune response which has favored mRNA use towards immunotherapeutic vaccination strategies. However, for non-immunotherapy related applications this intrinsic immune-stimulatory activity directly interferes with the aimed therapeutic outcome, as it can seriously compromise the expression of the desired protein. This review presents an overview of the immune-related obstacles that limit mRNA advance for non-immunotherapy related applications

DNA immunization as a technology platform for monoclonal antibody induction

To combat the threat of many emerging infectious diseases, DNA immunization offers a unique and powerful approach to the production of high-quality monoclonal antibodies (mAbs) against various pathogens. Compared with traditional protein-based immunization approaches, DNA immunization is efficient for testing novel immunogen designs, does not require the production or purification of proteins from a pathogen or the use of recombinant protein technology and is effective at generating mAbs against conformation-sensitive targets. Although significant progress in the use of DNA immunization to generate mAbs has been made over the last two decades, the literature does not contain an updated summary of this experience. The current review provides a comprehensive analysis of the literature, including our own work, describing the use of DNA immunization to produce highly functional mAbs, in particular, those against emerging infectious diseases. Critical factors such as immunogen design, delivery approach, immunization schedule, use of immune modulators and the role of final boost immunization are discussed in detail

Discal attachments of the human temporomandibular joint

The document attached has been archived with permission from the Australian Dental Association (8th Jan 2007). An external link to the publisher’s copy is included.Background: Despite its clinical significance, the anatomy of the human temporomandibular joint (TMJ) and its relationship to the lateral pterygoid muscle remains poorly described and often misrepresented in standard texts. The aim of this study was to describe how the anterior and posterior attachments of the TMJ disc vary between lateral, central and medial regions of the joint. Methods: Ten left TMJs were removed en bloc from cadavers and serial sections were made at 3-4mm intervals. Observations were made to ascertain the anterior and posterior attachments of the disc and the joint structures were traced from standardized photographs. Results: Laterally, the capsule and lateral discal ligament merged prior to their attachment at the condylar pole. Medially, muscle fibres, capsule and the disc converged on the medial pole of the condyle. There was no evidence that fibres of the upper head of the lateral pterygoid muscle inserted directly into the disc. The upper head inserted into the condyle either directly at the pterygoid fovea or via a central tendon or indirectly via the capsule. Posteriorly, the superior part of the posterior attachment of the disc attached to the cartilaginous meatus and tympanic part of the temporal bone. The inferior part of the posterior attachment of the disc attached to the posterior surface of the condyle. In four joints, this attachment was folded beneath the posterior band of the disc, creating a wedge-shaped flap that ran medio-laterally. Conclusion: This study is in broad agreement with other anatomical TMJ studies but there are two main points of difference. Firstly, a true muscle insertion of the superior head of the lateral pterygoid muscle to the disc was not observed. Secondly, a wedge-shaped flap of retrodiscal tissue was identified between the condyle and the disc.JE Christo, S Bennett, TM Wilkinson and GC Townsen

Li14Ln5[Si11N19O5]O2F2 with Ln = Ce, Nd-Representatives of a Family of Potential Lithium Ion Conductors

The isotypic layered oxonitridosilicates Li14Ln5[Si11N19O5]O2F2 (Ln = Ce, Nd) have been synthesized using Li as fluxing agent and crystallize in the orthorhombic space group Pmmn (Z = 2, Li14Ce5[Si11N19O5]O2F2: a = 17.178(3), b = 7.6500(15), c = 10.116(2) Å, R1 = 0.0409, wR2 = 0.0896; Li14Nd5 Si11N19O5]O2F2: a = 17.126(2), b = 7.6155 15), c = 10.123(2) Å, R1 = 0.0419, wR2 = 0.0929). The silicate layers consist of dreier and sechser rings interconnected via common corners, yielding an unprecedented silicate substructure. A topostructural analysis indicates possible 1D ion migration pathways between five crystallographic independent Li positions. The specific Li-ionic conductivity and its temperature dependence were determined by impedance spectroscopy as well as DC polarization/depolarization measurements. The ionic conductivity is on the order of 5 × 10−5 S/cm at 300°C, while the activation energy is 0.69 eV. Further adjustments of the defect chemistry (e.g., through doping)can make these compounds interesting candidates for novel oxonitridosilicate based ion conductors

The specific heat of superfluids near the transition temperature

The specific heat of the $x-y$ model is studied on cubic lattices of sizes $L \times L \times L$ and on lattices $L \times L \times H$ with $L \gg H$ (i.e. on lattices representing a film geometry) using the Cluster Monte Carlo method. Periodic boundary conditions were applied in all directions. In the cubic case we obtained the ratio of the critical exponents $\alpha/\nu$ from the size dependence of the energy density at the critical temperature $T_{\lambda}$. Using finite--size scaling theory, we find that while for both geometries our results scale to universal functions, these functions differ for the different geometries. We compare our findings to experimental results and results of renormalization group calculations.Comment: self-unpacking uuencoded PostScript file (for instructions see the beginning of the file), 18 pages