Ductile-regime turning of germanium and silicon

Single-point diamond turning of silicon and germanium was investigated in order to clarify the role of cutting depth in coaxing a ductile chip formation in normally brittle substances. Experiments based on the rapid withdrawal of the tool from the workpiece have shown that microfracture damage is a function of the effective depth of cut (as opposed to the nominal cutting depth). In essence, damage created by the leading edge of the tool is removed several revolutions later by lower sections of the tool edge, where the effective cutting depth is less. It appears that a truly ductile cutting response can be achieved only when the effective cutting depth, or critical chip thickness, is less than about 20 nm. Factors such as tool rake angle are significant in that they will affect the actual value of the critical chip thickness for transition from brittle to ductile response. It is concluded that the critical chip thickness is an excellent parameter for measuring the effects of machining conditions on the ductility of the cut and for designing tool-workpiece geometry in both turning and grinding

Operation Program for the Spatially Phase-Shifted Digital Speckle Pattern Interferometer - SPS-DSPI

SPS-DSPI software has been revised so that Goddard optical engineers can operate the instrument, instead of data programmers. The user interface has been improved to view the data collected by the SPS-DSPI, with a real-time mode and a play-back mode. The SPS-DSPI has been developed by NASA/GSFC to measure the temperature distortions of the primary-mirror backplane structure for the James Webb Space Telescope. It requires a team of computer specialists to run successfully, because, at the time of this reporting, it just finished the prototype stage. This software improvement will transition the instrument to become available for use by many programs that measure distortio

Protein Ontology: A controlled structured network of protein entities

The Protein Ontology (PRO; http://proconsortium.org) formally defines protein entities and explicitly represents their major forms and interrelations. Protein entities represented in PRO corresponding to single amino acid chains are categorized by level of specificity into family, gene, sequence and modification metaclasses, and there is a separate metaclass for protein complexes. All metaclasses also have organism-specific derivatives. PRO complements established sequence databases such as UniProtKB, and interoperates with other biomedical and biological ontologies such as the Gene Ontology (GO). PRO relates to UniProtKB in that PRO’s organism-specific classes of proteins encoded by a specific gene correspond to entities documented in UniProtKB entries. PRO relates to the GO in that PRO’s representations of organism-specific protein complexes are subclasses of the organism-agnostic protein complex terms in the GO Cellular Component Ontology. The past few years have seen growth and changes to the PRO, as well as new points of access to the data and new applications of PRO in immunology and proteomics. Here we describe some of these developments

Galaxy redshift surveys selected by neutral hydrogen using FAST

We discuss the possibility of performing a substantial spectroscopic galaxy redshift survey selected via the 21cm emission from neutral hydrogen using the Five-hundred metre Aperture Spherical Telescope (FAST) to be built in China. We consider issues related to the estimation of the source counts and optimizations of the survey, and discuss the constraints on cosmological models that such a survey could provide. We find that a survey taking around two years could detect ~10^7 galaxies with an average redshift of ~0.15 making the survey complementary to those already carried out at optical wavelengths. These conservative estimates have used the z=0 HI mass function and have ignored the possibility of evolution. The results could be used to constrain Gamma = (Omega_m h) to 5 per cent and the spectral index, n_s, to 7 per cent independent of cosmic microwave background data. If we also use simulated power spectra from the Planck satellite, we can constrain w to be within 5 per cent of -1.Comment: 13 pages, 15 figures, Accepted by MNRAS, minor correction

Forming Mandrels for X-Ray Mirror Substrates

Precision forming mandrels are one element in X-ray mirror development at NASA. Current mandrel fabrication process is capable of meeting the allocated precision requirements for a 5 arcsec telescope. A manufacturing plan is outlined for a large IXO-scale program

Adaptive Motor Imagery: A Multimodal Study of Immobilization-Induced Brain Plasticity.

The consequences of losing the ability to move a limb are traumatic. One approach that examines the impact of pathological limb nonuse on the brain involves temporary immobilization of a healthy limb. Here, we investigated immobilization-induced plasticity in the motor imagery (MI) circuitry during hand immobilization. We assessed these changes with a multimodal paradigm, using functional magnetic resonance imaging (fMRI) to measure neural activation, magnetoencephalography (MEG) to track neuronal oscillatory dynamics, and transcranial magnetic stimulation (TMS) to assess corticospinal excitability. fMRI results show a significant decrease in neural activation for MI of the constrained hand, localized to sensorimotor areas contralateral to the immobilized hand. MEG results show a significant decrease in beta desynchronization and faster resynchronization in sensorimotor areas contralateral to the immobilized hand. TMS results show a significant increase in resting motor threshold in motor cortex contralateral to the constrained hand, suggesting a decrease in corticospinal excitability in the projections to the constrained hand. These results demonstrate a direct and rapid effect of immobilization on MI processes of the constrained hand, suggesting that limb nonuse may not only affect motor execution, as evidenced by previous studies, but also MI. These findings have important implications for the effectiveness of therapeutic approaches that use MI as a rehabilitation tool to ameliorate the negative effects of limb nonuse

Switchgrass (\u3ci\u3ePanicum virgatum\u3c/i\u3e L.) polyubiquitin gene (\u3ci\u3ePvUbi1\u3c/i\u3e and \u3ci\u3ePvUbi2\u3c/i\u3e) promoters for use in plant transformation

Abstract Background The ubiquitin protein is present in all eukaryotic cells and promoters from ubiquitin genes are good candidates to regulate the constitutive expression of transgenes in plants. Therefore, two switchgrass (Panicum virgatum L.) ubiquitin genes (PvUbi1 and PvUbi2) were cloned and characterized. Reporter constructs were produced containing the isolated 5\u27 upstream regulatory regions of the coding sequences (i.e. PvUbi1 and PvUbi2 promoters) fused to the uidA coding region (GUS) and tested for transient and stable expression in a variety of plant species and tissues. Results PvUbi1 consists of 607 bp containing cis-acting regulatory elements, a 5\u27 untranslated region (UTR) containing a 93 bp non-coding exon and a 1291 bp intron, and a 918 bp open reading frame (ORF) that encodes four tandem, head -to-tail ubiquitin monomer repeats followed by a 191 bp 3\u27 UTR. PvUbi2 consists of 692 bp containing cis-acting regulatory elements, a 5\u27 UTR containing a 97 bp non-coding exon and a 1072 bp intron, a 1146 bp ORF that encodes five tandem ubiquitin monomer repeats and a 183 bp 3\u27 UTR. PvUbi1 and PvUbi2 were expressed in all examined switchgrass tissues as measured by qRT-PCR. Using biolistic bombardment, PvUbi1 and PvUbi2 promoters showed strong expression in switchgrass and rice callus, equaling or surpassing the expression levels of the CaMV 35S, 2x35S, ZmUbi1, and OsAct1 promoters. GUS staining following stable transformation in rice demonstrated that the PvUbi1 and PvUbi2 promoters drove expression in all examined tissues. When stably transformed into tobacco (Nicotiana tabacum), the PvUbi2+3 and PvUbi2+9 promoter fusion variants showed expression in vascular and reproductive tissues. Conclusions The PvUbi1 and PvUbi2 promoters drive expression in switchgrass, rice and tobacco and are strong constitutive promoter candidates that will be useful in genetic transformation of monocots and dicots