Synthesis and Structure of a Tungsten Dimer with a W-W Bond Order of 3.5

Reaction of W2(mhp)4, where mhp is the anion of 2-hydroxy-6- methylpyridine, with AICI3 in refluxing diglyme provides the new paramagnetic compound W2Cl2(mhp)3 • CH2CI2 in 67 percent yield after recrystallization from dichloromethane. The source of the oxidant for oxidation of tungsten from W(2.0) to W(2.5) was not identified. Orange-brown crystals of the new compound belong to the noncentric orthorhombic space group P2I2424 with a = 13.150(6), b = 21.24(1) and c = 8.738(4) Å, Z = 4. Refinement of the structure provided R(RW) = 0.058(0.080) and a W-W bond distance of 2.214(2) Å, 0.053 Å longer than that in W2(mhp)4 • CH2CI2. The W-W bond has a bond order of 3.5 corresponding to the bonding orbital population a27i481. Strong bands arising from W-Cl stretching modes occur at 321 and 289 cm-1 in the IR spectra, and a weak band at 782 nm (e ~ 600 M_1cm_1) in the UV-visible spectrum may correspond to the 8 —> 8 electronic transition. The EPR spectrum shows a strong, nearly symmetric, absorption with g = 1.842. Cyclic voltammetry in dichloromethane reveals a quasi-reversible reduction at Ey2 = —0.7 V vs. SSCE and an irreversible oxidation at +0.3 V

List of high purity metals available from American producers

All prices given in this report are quoted from the producer and are subject to change. The stated purities and analyses are also those of the producer. We have made no attempt to check these analyses and assume no responsibility as to their reliability. Where more detailed information is needed concerning the latest prices, purity and other shapes of a particular metal, we suggest direct correspondence with the listed producers. It is our intention that only those who produce and supply pure metals be included in this compilation. Some listings include grades of metal of not exceptional purity, especially for some of the less common metals, and are included because they could be of interest in research on alloys where that metal is a minor constituent

Rapid, photoinduced electron transfer-modulated, turn-on fluorescent probe for detection and cellular imaging of biologically significant thiols

© 2014 American Chemical Society. There is a very limited number of existing probes whose fluorescence is turned on in the presence of the class of biological thiols made up of glutathione, cysteine, and homocysteine. The extant probes for this class of biological thiols commonly have poor aqueous solubility and long analyte response times, and they demand a very high probe/thiol ratio for decreased time of significant reporter signal generation; knowledge regarding their selectivity with respect to other sulfur-based analytes is unclear. Described here is a previously unreported photoinduced electron-transfer-quenched probe (HMBQ-Nap 1) that offers highly selective and rapid in vitro detection of this class of biologically important thiols at low concentrations and low probe/thiol ratio, and importantly, very rapid imaging of these biological thiols in human cells. (Chemical Presented)

Final Scientific/Technical Report

The overall goal of this project was to establish an education and training program in biobased products at Iowa State University (ISU). In particular, a graduate program in Biorenewable Resources and Technology (BRT) was to be established as a way of offering students advanced study in the use of plant- and crop-based resources in the production of biobased products. The program was to include three fundamental elements: an academic program, a research program, and industrial interactions. The academic program set out to introduce a new graduate major in Biorenewable Resources and Technology. Unlike other schools, which only offer certificates or areas of emphasis in biobased products, Iowa State University offers both M.S. and Ph.D degrees through its graduate program. Core required courses in Biorenewable Resources and Technology include a foundation course entitled Fundamentals of Biorenewable Resources (BRT 501); a seminar course entitled Biobased Products Seminar (BRT 506); a laboratory course, and a special topics laboratory course. The foundation course is a three-credit course introducing students to basic concepts in biorenewable resources and technology. The seminar course provides students with an opportunity to hear from nationally and internationally recognized leaders in the field. The laboratory requirement is a 1-credit laboratory course or a special topics laboratory/research experience (BRT 591L). As part of student recruitment, quarter-time assistantships from DOE funds were offered to supplement assistantships provided by faculty to students. Research was built around platform teams in an effort to encourage interdisciplinary research and collaborative student learning in biorenewable resources. A platform is defined as the convergence of enabling technologies into a highly integrated system for transforming a specific feedstock into desired products. The platform teams parallel the way industry conducts research and product development. Platform teams organize faculty and students for cross-disciplinary, systems-oriented research and collaborative learning. To date, nine platforms have been developed, although these will most likely be reorganized into a smaller number of broader topics. In the spring of 2004, BRT faculty initiated a regional partnership and collaborative learning program with colleagues at the University of Minnesota, Kansas State University, and South Dakota State University to develop distance education courses in biorenewable resources and technology. As a fledgling graduate program, the BRT graduate program didn’t have the breadth of resources to offer a large number of courses in biorenewables. Other schools faced a similar problem. The academic consortium as first conceived would allow students from the member schools to enroll in biorenewables courses from any of the participating schools, which would assure the necessary enrollment numbers to offer specialized course work. Since its inception, the collaborative curriculum partnership has expanded to include Louisiana State University and the University of Wisconsin. A second international curriculum development campaign was also initiated in the spring of 2004. In particular, several BRT faculty teamed with colleagues at the University of Arkansas, University of Washington, University of Gent (Belgium), National Polytechnic Institute of Toulouse (France), and Technical University of Graz (Austria) to develop an EU-US exchange program in higher education and vocational education/training (entitled “Renewable Resources and Clean Technology”)

Analysis of schizophrenia-related genes and electrophysiological measures reveals ZNF804A association with amplitude of P300b elicited by novel sounds

Several genes have recently been identified as risk factors for schizophrenia (SZ) by genome-wide association studies (GWAS), including ZNF804A which is thought to function in transcriptional regulation. However, the downstream pathophysiological changes that these genes confer remain to be elucidated. In 143 subjects (68 clinical high risk, first episode or chronic cases; 75 controls), we examined the association between 21 genetic markers previously identified by SZ GWAS or associated with putative intermediate phenotypes of SZ against three event-related potential (ERP) measures: mismatch negativity (MMN), amplitude of P300 during an auditory oddball task, and P300 amplitude during an auditory novelty oddball task. Controlling for age and sex, significant genetic association surpassing Bonferroni correction was detected between ZNF804A marker rs1344706 and P300 amplitude elicited by novel sounds (beta=4.38, P=1.03 × 10−4), which is thought to index orienting of attention to unexpected, salient stimuli. Subsequent analyses revealed that the association was driven by the control subjects (beta=6.35, P=9.08 × 10−5), and that the risk allele was correlated with higher novel P300b amplitude, in contrast to the significantly lower amplitude observed in cases compared to controls. Novel P300b amplitude was significantly correlated with a neurocognitive measure of auditory attention under interference conditions, suggesting a relationship between novel P300b amplitude and higher-order attentional processes. Our results suggest pleiotropic effects of ZNF804A on risk for SZ and neural mechanisms that are indexed by the novel P300b ERP component

The Application of DTI to Investigate White Matter Abnormalities in Schizophrenia

Schizophrenia is a serious and disabling mental disorder that affects approximately 1% of the general population, with often devastating effects on the psychological and financial resources of the patient, family, and larger community. The etiology of schizophrenia is not known, although it likely involves several interacting biological and environmental factors that predispose an individual to schizophrenia. However, although the underlying pathology remains unknown, it has been believed that brain abnormalities would ultimately be linked to the etiology of schizophrenia. This theory was rekindled in the 1970s, when the first computer-assisted tomography (CT) study showed enlarged lateral ventricles in schizophrenia. Since that time, there have been many improvements in MR acquisition and image processing, including the introduction of positron emission tomography (PET), followed by functional MR (fMRI), and diffusion tensor imaging (DTI). These advances have led to an appreciation of the critical role that brain abnormalities play in schizophrenia. While structural MRI has proven to be useful in investigating and detecting gray matter abnormalities in schizophrenia, the investigation of white matter has proven to be more challenging as white matter appears homogeneous on conventional MRI and the fibers connecting different brain regions cannot be appreciated. With the development of DTI, we are now able to investigate white matter abnormalities in schizophrenia

Telephone conversation impairs sustained visual attention via a central bottleneck

Recent research has shown that holding telephone conversations disrupts one's driving ability. We asked whether this effect could be attributed to a visual attention impairment. In Experiment 1, participants conversed on a telephone or listened to a narrative while engaged in multiple object tracking (MOT), a task requiring sustained visual attention. We found that MOT was disrupted in the telephone conversation condition, relative to single-task MOT performance, but that listening to a narrative had no effect. In Experiment 2, we asked which component of conversation might be interfering with MOT performance. We replicated the conversation and single-task conditions of Experiment 1 and added two conditions in which participants heard a sequence of words over a telephone. In the shadowing condition, participants simply repeated each word in the sequence. In the generation condition, participants were asked to generate a new word based on each word in the sequence. Word generation interfered with MOT performance, but shadowing did not. The data indicate that telephone conversation disrupts attention at a central stage, the act of generating verbal stimuli, rather than at a peripheral stage, such as listening or speaking

Reduced interhemispheric connectivity in schizophrenia-tractography based segmentation of the corpus callosum

A reduction in interhemispheric connectivity is thought to contribute to the etiology of schizophrenia. Diffusion Tensor Imaging (DTI) measures the diffusion of water and can be used to describe the integrity of the corpus callosum white matter tracts, thereby providing information concerning possible interhemispheric connectivity abnormalities. Previous DTI studies in schizophrenia are inconsistent in reporting decreased Fractional Anisotropy (FA), a measure of anisotropic diffusion, within different portions of the corpus callosum. Moreover, none of these studies has investigated corpus callosum systematically, using anatomical subdivisions

The Benefits and the Costs of Using Auditory Warning Messages in Dynamic Decision Making Settings

The failure to notice critical changes in both visual and auditory scenes may have important consequences for performance in complex dynamic environments, especially those related to security such as aviation, surveillance during major events, and command and control of emergency response. Previous work has shown that a significant number of situation changes remain undetected by operators in such environments. In the current study, we examined the impact of using auditory warning messages to support the detection of critical situation changes and to a broader extent the decision making required by the environment. Twenty-two participants performed a radar operator task involving multiple subtasks while detecting critical task-related events that were cued by a specific type of audio message. Results showed that about 22% of the critical changes remained undetected by participants, a percentage similar to that found in previous work using visual cues to support change detection. However, we found that audio messages tended to bias threat evaluation towards perceiving objects as more threatening than they were in reality. Such findings revealed both benefits and costs associated with using audio messages to support change detection in complex dynamic environments

Lynx X-Ray Observatory: An Overview

Lynx, one of the four strategic mission concepts under study for the 2020 Astrophysics Decadal Survey, provides leaps in capability over previous and planned x-ray missions and provides synergistic observations in the 2030s to a multitude of space- and ground-based observatories across all wavelengths. Lynx provides orders of magnitude improvement in sensitivity, on-axis subarcsecond imaging with arcsecond angular resolution over a large field of view, and high-resolution spectroscopy for point-like and extended sources in the 0.2- to 10-keV range. The Lynx architecture enables a broad range of unique and compelling science to be carried out mainly through a General Observer Program. This program is envisioned to include detecting the very first seed black holes, revealing the high-energy drivers of galaxy formation and evolution, and characterizing the mechanisms that govern stellar evolution and stellar ecosystems. The Lynx optics and science instruments are carefully designed to optimize the science capability and, when combined, form an exciting architecture that utilizes relatively mature technologies for a cost that is compatible with the projected NASA Astrophysics budget