Characterisation of the trans-influence, and its inverse

The trans-influence (TI), whereby the bond directly opposite a strong σ-donor, in certain d-block complexes, is relatively lengthened. The inverse trans-influence (ITI), whereby the analogous bond in certain f-block complexes, is relatively shortened. The purpose of this work is investigate the origin of the TI and its inverse (ITI) in a variety of d- and f-block species of the [MOX5]− form (M = U, Mo, W, and halide X =F, Cl, Br). Relative magnitudes of the influences as both a function of the metal species and halide ligand are determined computationally. Several model chemistries are tested, spanning eight basis sets and seven DFT exchange–correlation functionals. Characterisation of the complexes in the ground state considers bond length, QTAIM, and natural bond orbital (NBO) analyses. The results demonstrate that the d-block TIs have generally higher magnitudes than the f-block ITIs, and that regardless of metal centre, the magnitudes of the influences are greatest in the F-ligand complexes, and lowest in the Br-ligand complexes. NBO analysis identifies that the trans-bonds, relative to the cis-bonds in the ITI-exhibiting [UOX5]− species, exhibit reduced f- and s-orbital, and enhanced d-orbital character from the U contributions. A novel examination of the influence of electronic excitation (as studied using TDDFT) on the TI and ITI is considered. The geometries of the ground and of pertinent excited states are compared to identify key excitations that significantly alter the influences. Analysis of three excitations proved particularly insightful; two exclusive to the fblock species, and one common to both the d- and f-block species. For the latter excitations yielded a reduction of the TI in the d-block and a reduction (and reversal) of the ITI in the f-block species. The results hint at a possible common electronic origin for the TI and ITI and demonstrate that these influences can be moderated by electronic excitation

A unified approach for composite cost reporting and prediction in the ACT program

The Structures Technology Program Office (STPO) at NASA Langley Research Center has held two workshops with representatives from the commercial airframe companies to establish a plan for development of a standard cost reporting format and a cost prediction tool for conceptual and preliminary designers. This paper reviews the findings of the workshop representatives with a plan for implementation of their recommendations. The recommendations of the cost tracking and reporting committee will be implemented by reinstituting the collection of composite part fabrication data in a format similar to the DoD/NASA Structural Composites Fabrication Guide. The process of data collection will be automated by taking advantage of current technology with user friendly computer interfaces and electronic data transmission. Development of a conceptual and preliminary designers' cost prediction model will be initiated. The model will provide a technically sound method for evaluating the relative cost of different composite structural designs, fabrication processes, and assembly methods that can be compared to equivalent metallic parts or assemblies. The feasibility of developing cost prediction software in a modular form for interfacing with state of the art preliminary design tools and computer aided design (CAD) programs is assessed

Paleosoils and coal in the distal part of the Spanish Buntsandstein (Menorca and Mallorca, Balearic Islands)

Abstract not availabl

Cost-efficient manufacturing of composite structures

The Advanced Composites Technology (ACT) program is seeking research breakthroughs that will allow structures made of graphite epoxy materials to replace metals in the wings and fuselages of future aircrafts. NASA's goals are to reduce acquisition cost by 20 to 25 percent, structural weight for a resized aircraft by 40 to 50 percent, and the number of parts by half compared to current production aluminum aircraft. The innovative structural concepts, materials, and fabrication techniques emerging from the ACT program are described, and the relationship between aerospace developments and industrial, commercial, and sporting goods applications are discussed

Moving forwards with the standard THC unit [Commentary]

There is international support for a standard tetrahydrocannabinol (THC) unit, which could improve the precision with which we understand, regulate and communicate dose-related risks and benefits to consumers. Implementing the standard THC unit in legal recreational cannabis markets would represent an important step forward

Investigation Into the use of C- and N-terminal GFP Fusion Proteins for Subcellular Localization Studies Using Reverse Transfection Microarrays

Reverse transfection microarrays were described recently as a high throughput method for studying gene function. We have investigated the use of this technology for determining the subcellular localization of proteins. Genes encoding 16 proteins with a variety of functions were placed in Gateway expression constructs with 3′ or 5′ green fluorescent protein (GFP) tags. These were then packaged in transfection reagent and spotted robotically onto a glass slide to form a reverse transfection array. HEK293T cells were grown over the surface of the array until confluent and GFP fluorescence visualized by confocal microscopy. All C-terminal fusion proteins localized to cellular compartments in accordance with previous studies and/or bioinformatic predictions. However, less than half of the N-terminal fusion proteins localized correctly. Of those that were not in concordance with the C-terminal tagged proteins, half did not exhibit expression and the remainder had differing subcellular localizations to the C-terminal fusion protein. This data indicates that N-terminal tagging with GFP adversely affects the protein localization in reverse transfection assays, whereas tagging with GFP at the C-terminal is generally better in preserving the localization of the native protein. We discuss these results in the context of developing high-throughput subcellular localization assays based on the reverse transfection array technology

Estimating the location of the open-closed magnetic field line boundary from auroral images

The open-closed magnetic field line boundary (OCB) delimits the region of open magnetic flux forming the polar cap in the Earth’s ionosphere. We present a reliable, automated method for determining the location of the poleward auroral luminosity boundary (PALB) from far ultraviolet (FUV) images of the aurora, which we use as a proxy for the OCB. This technique models latitudinal profiles of auroral luminosity as both a single and double Gaussian function with a quadratic background to produce estimates of the PALB without prior knowledge of the level of auroral activity or of the presence of bifurcation in the auroral oval. We have applied this technique to FUV images recorded by the IMAGE satellite from May 2000 until August 2002 to produce a database of over a million PALB location estimates, which is freely available to download. From this database, we assess and illustrate the accuracy and reliability of this technique during varying geomagnetic conditions. We find that up to 35% of our PALB estimates are made from double Gaussian fits to latitudinal intensity profiles, in preference to single Gaussian fits, in nightside magnetic local time (MLT) sectors. The accuracy of our PALBs as a proxy for the location of the OCB is evaluated by comparison with particle precipitation boundary (PPB) proxies from the DMSP satellites. We demonstrate the value of this technique in estimating the total rate of magnetic reconnection from the time variation of the polar cap area calculated from our OCB estimates