The effects of metal ion and ligand substitution on the spectroscopic properties of metal complexes.

Includes bibliographical references.Metal-nitrogen stretching vibrations in Co(II), Ni(II), Cu(II) and Zn(II) chloride 4-methylaniline complexes are assigned by ¹⁵N-labelling in conjunction with a consideration of the relative crystal field stabilizition energies of the metal ions. Bands in the ultraviolet electronic spectra of Cu(II) β-ketoenolate complexes are more conclusively assigned by comparison of the spectra of the β-ketoenolates, their sodium salts and the copper complexes. The effect of ligand substitution on the infrared spectra of Cu(II) benzoylacetanilide complexes and their methanol adducts is used to assign copper-oxygen stretching frequencies. The effect of ligand substitution on the ultraviolet electronic spectra is used to estimate the extent of π-interaction in these complexes. The infrared spectra of six ¹⁵N-labelled Co(II), Ni(II), Cu(II) and Zn(II) N-salicylideneanthranilate complexes yield assignments of metal-ligand and certain ligand vibrations. These assignments are supported by observing the effects of metal ion and ligand substitution on the spectra. The shifts observed in the metal-ligand stretching frequencies are related to the relative crystal field stabilization energies of the metal ions and to the electron releasing and withdrawing capacities of the ligand substituents. Assignments of metal-ligand vibrations in the infrared spectra of Ni(II) and Cu(II) benzoylbenzilidenehydrazone complexes and Co(II), Ni(II), Cu(II) and Zn(II) benzoylsalicylidenehydrazone complexes are made by observing the effects of metal ion and ligand substitution on the spectra. The infrared spectra of three ¹⁵N-labelled Ni(II), Co(II) and Cu(II) triarylformazan complexes yield assignments of metal-ligand and certain ligand vibrations. The effect of ligand substitution on the infrared spectra of Ni(II) triarylformazan complexes is related to the electron releasing or withdrawing capacities of the substituents. A total of 168 complexes, of which 131 have not previously been reported, has been synthesized and discussed

The Relationship between Real-Time EEG Engagement, Distraction and Workload Estimates and Simulator-Based Driving Performance

Identifying potentially impaired drivers is often dependent upon using cognitive testing from a controlled environment (clinic, laboratory) to predict behavior in a dynamic and unpredictable real world driving environment. The goal of this study was to determine the feasibility, and validity, of using a wireless EEG system to ultimately differentiate between impaired and unimpaired drivers. We utilized the B-Alert X10 portable wireless EEG/ECG system and applied previously validated EEG algorithms estimating engagement, workload, and distraction within a sample of normal control (n = 10) and HIV seropositive individuals (n = 14). Participants underwent a 30-minute fully interactive driving simulation. Overall, the HIV+ group evidenced significantly higher distraction during the simulation. When grouped according to poor and good performers on the simulation (regardless of HIV serostatus), those performing worse on the simulation had higher distraction, with a trend for lower workload, levels. We then examined EEG profiles immediately preceding a crash. Prior to a crash, participants evidenced a significant increase in distraction ~ 10-14 seconds leading up to the crash; the greatest increase was seen in the HIV+ group. These preliminary data support the potential utility of using EEG data in patient populations to identify individuals who might be at risk for impaired drivin

Magnetic field dependence of the internal quality factor and noise performance of lumped-element kinetic inductance detectors

We present a technique for increasing the internal quality factor of kinetic inductance detectors (KIDs) by nulling ambient magnetic fields with a properly applied magnetic field. The KIDs used in this study are made from thin-film aluminum, they are mounted inside a light-tight package made from bulk aluminum, and they are operated near $150 \, \mathrm{mK}$. Since the thin-film aluminum has a slightly elevated critical temperature ($T_\mathrm{c} = 1.4 \, \mathrm{K}$), it therefore transitions before the package ($T_\mathrm{c} = 1.2 \, \mathrm{K}$), which also serves as a magnetic shield. On cooldown, ambient magnetic fields as small as approximately $30 \, \mathrm{\mu T}$ can produce vortices in the thin-film aluminum as it transitions because the bulk aluminum package has not yet transitioned and therefore is not yet shielding. These vortices become trapped inside the aluminum package below $1.2 \, \mathrm{K}$ and ultimately produce low internal quality factors in the thin-film superconducting resonators. We show that by controlling the strength of the magnetic field present when the thin film transitions, we can control the internal quality factor of the resonators. We also compare the noise performance with and without vortices present, and find no evidence for excess noise beyond the increase in amplifier noise, which is expected with increasing loss.Comment: 5 pages, 4 figure

Acute lung injury following intravascular complement activation; Association with toxic oxygen metabolites from neutrophils

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23825/1/0000064.pd

Using agent-based modelling to simulate social-ecological systems across scales

Agent-based modelling (ABM) simulates Social-Ecological-Systems (SESs) based on the decision-making and actions of individual actors or actor groups, their interactions with each other, and with ecosystems. Many ABM studies have focused at the scale of villages, rural landscapes, towns or cities. When considering a geographical, spatially-explicit domain, current ABM architecture is generally not easily translatable to a regional or global context, nor does it acknowledge SESs interactions across scales sufficiently; the model extent is usually determined by pragmatic considerations, which may well cut across dynamical boundaries. With a few exceptions, the internal structure of governments is not included when representing them as agents. This is partly due to the lack of theory about how to represent such as actors, and because they are not static over the time-scales typical for social changes to have significant effects. Moreover, the relevant scale of analysis is often not known a priori, being dynamically determined, and may itself vary with time and circumstances. There is a need for ABM to cross the gap between micro-scale actors and larger-scale environmental, infrastructural and political systems in a way that allows realistic spatial and temporal phenomena to emerge; this is vital for models to be useful for policy analysis in an era when global crises can be triggered by small numbers of micro-level actors. We aim with this thought-piece to suggest conceptual avenues for implementing ABM to simulate SESs across scales, and for using big data from social surveys, remote sensing or other sources for this purpose

Tunable Semiconducting Polymer Nanoparticles with INDT-Based Conjugated Polymers for Photoacoustic Molecular Imaging.

Photoacoustic imaging combines both excellent spatial resolution with high contrast and specificity, without the need for patients to be exposed to ionizing radiation. This makes it ideal for the study of physiological changes occurring during tumorigenesis and cardiovascular disease. In order to fully exploit the potential of this technique, new exogenous contrast agents with strong absorbance in the near-infrared range, good stability and biocompatibility, are required. In this paper, we report the formulation and characterization of a novel series of endogenous contrast agents for photoacoustic imaging in vivo. These contrast agents are based on a recently reported series of indigoid π-conjugated organic semiconductors, coformulated with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, to give semiconducting polymer nanoparticles of about 150 nm diameter. These nanoparticles exhibited excellent absorption in the near-infrared region, with good photoacoustic signal generation efficiencies, high photostability, and extinction coefficients of up to three times higher than those previously reported. The absorption maximum is conveniently located in the spectral region of low absorption of chromophores within human tissue. Using the most promising semiconducting polymer nanoparticle, we have demonstrated wavelength-dependent differential contrast between vasculature and the nanoparticles, which can be used to unambiguously discriminate the presence of the contrast agent in vivo

The heart of Rett syndrome: A quantitative analysis of cardiac repolarization

BACKGROUND: Rett syndrome (RTT) is a developmental encephalopathy disorder that is associated with a high incidence of sudden death presumably from cardiorespiratory etiologies. Electrocardiogram (ECG) abnormalities, such as prolonged heart-rate corrected QT (QTc) interval, are markers of cardiac repolarization and are associated with potentially lethal ventricular arrhythmias. This study investigates the cardiac repolarization characteristics of RTT patients, including QTc and T-wave morphology characteristics. METHODS: A retrospective quantitative analysis on 110 RTT patients and 124 age and sex-matched healthy controls was conducted. RESULTS: RTT patients had longer QTc, more abnormal T-wave morphology, and greater heterogeneity of cardiac repolarization parameters compared to controls. Even RTT patients without prolonged QTc had more abnormal ECG and T-wave characteristics than controls. Among RTT patients, CONCLUSIONS: Cardiac repolarization abnormalities are present in RTT patients, even without long QTc. T-wave morphology is related to RTT genotype and may be predictive of mortality. These findings could be used to help the management and monitoring of RTT patients

Very Metal-poor Stars in the Outer Galactic Bulge Found by the Apogee Survey

Despite its importance for understanding the nature of early stellar generations and for constraining Galactic bulge formation models, at present little is known about the metal-poor stellar content of the central Milky Way. This is a consequence of the great distances involved and intervening dust obscuration, which challenge optical studies. However, the Apache Point Observatory Galactic Evolution Experiment (APOGEE), a wide-area, multifiber, high-resolution spectroscopic survey within Sloan Digital Sky Survey III (SDSS-III), is exploring the chemistry of all Galactic stellar populations at infrared wavelengths, with particular emphasis on the disk and the bulge. An automated spectral analysis of data on 2,403 giant stars in twelve fields in the bulge obtained during APOGEE commissioning yielded five stars with low metallicity([Fe/H]$\le-1.7$), including two that are very metal-poor [Fe/H]$\sim-2.1$ by bulge standards. Luminosity-based distance estimates place the five stars within the outer bulge, where other 1,246 of the analyzed stars may reside. A manual reanalysis of the spectra verifies the low metallicities, and finds these stars to be enhanced in the $\alpha$-elements O, Mg, and Si without significant $\alpha$-pattern differences with other local halo or metal-weak thick-disk stars of similar metallicity, or even with other more metal-rich bulge stars. While neither the kinematics nor chemistry of these stars can yet definitively determine which, if any, are truly bulge members, rather than denizens of other populations co-located with the bulge, the newly-identified stars reveal that the chemistry of metal-poor stars in the central Galaxy resembles that of metal-weak thick-disk stars at similar metallicity.Comment: 6 pages, 3 figures, 2 table

The Apache Point Observatory Galactic Evolution Experiment: First Detection of High Velocity Milky Way Bar Stars

Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for ~4700 K/M-giant stars in the Milky Way bulge. These high-resolution (R \sim 22,500), high-S/N (>100 per resolution element), near-infrared (1.51-1.70 um; NIR) spectra provide accurate RVs (epsilon_v~0.2 km/s) for the sample of stars in 18 Galactic bulge fields spanning -1-32 deg. This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold (sigma_v~30 km/s), high-velocity peak (V_GSR \sim +200 km/s) is found to comprise a significant fraction (~10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galactic models suggests that these high RVs are best explained by stars in orbits of the Galactic bar potential, although some observational features remain unexplained.Comment: 7 pages, 4 figures, accepted for publication in ApJ Letter