Improved Atmospheric Characterization for Hyperspectral Exploitation

Airborne hyperspectral imaging (HSI) in the LWIR has shown utility in material detection and identification. This research seeks to determine the most effective methods to perform model-based atmospheric compensation of LWIR HSI data by comparing results obtained from different atmospheric profiles. The standard model for mid-latitude summer (MLS) and radiosonde data are compared to the National Operational Model Archive and Distribution System (NOMADS) numerical weather predictions and the Extreme and Percentile Environmental Reference Tables (ExPERT). The two latter atmospheric profiles are generated using the Laser Environmental Effects Definition and Reference (LEEDR) software. MLS has been a standard starting point for model-based atmospheric compensation codes, but this study tests the effectiveness of starting with a more accurate model of the atmosphere. The results suggest improvements can be obtained using NOMADS and ExPERT when compared to MLS and radiosonde approaches

Spin splitting of X-related donor impurity states in an AlAs barrier

We use magnetotunneling spectroscopy to observe the spin splitting of the ground state of an X-valley-related Si-donor impurity in an AlAs barrier. We determine the absolute magnitude of the effective Zeeman spin splitting factors of the impurity ground state to be g$_{I}$= 2.2 $\pm$ 0.1. We also investigate the spatial form of the electron wave function of the donor ground state, which is anisotropic in the growth plane

Magnetic-field-induced singularities in spin dependent tunneling through InAs quantum dots

Current steps attributed to resonant tunneling through individual InAs quantum dots embedded in a GaAs-AlAs-GaAs tunneling device are investigated experimentally in magnetic fields up to 28 T. The steps evolve into strongly enhanced current peaks in high fields. This can be understood as a field-induced Fermi-edge singularity due to the Coulomb interaction between the tunneling electron on the quantum dot and the partly spin polarized Fermi sea in the Landau quantized three-dimensional emitter.Comment: 5 pages, 4 figure

ETHYL GLUCURONIDE: A BIOMARKER TO IDENTIFY ALCOHOL USE BY HEALTH PROFESSIONALS RECOVERING FROM SUBSTANCE USE DISORDERS

Aims: Physicians recovering from substance-related disorders are usually allowed to return to practice if they agree to remain abstinent from drugs, including alcohol, and to undergo random urine testing. Over 9000 physicians are currently involved in such monitoring programs in the US. To date, it has been difficult to adequately monitor abstinence from alcohol due to the short half-life of alcohol and no other highly specific marker. Ethyl glucuronide (EtG), a direct metabolite of alcohol, offers an extended window for assessment of drinking status (up to 5 days). Our aim was to assess the potential value of EtG testing in abstinence-based monitoring programs. Patients and methods: Urine samples were obtained from 100 participants in a physician monitoring program and additional samples were subsequently obtained ‘for cause', ‘to verify positive urine alcohol, when drinking was denied' and ‘in high risk individuals'. All participants had signed contracts agreeing to remain abstinent from mood-altering drugs, including alcohol, and had agreed to random urine testing. EtG was determined using LC/MS-MS in addition to standard testing. The main outcome measure were urine specimens positive for EtG versus those positive based on standard testing for alcohol and other drugs. Results: Among the initial 100 random samples collected, no sample was positive for alcohol using standard testing; however, seven were positive for EtG (0.5-196 mg/l), suggesting recent alcohol use. Subsequent EtG testing was performed clinically during the course of monitoring. Of the 18 tests performed to date, eight of eight tests performed ‘for cause' were positive for EtG but negative for all other drugs including urine alcohol. All eight were confirmed positive by self reported drinking by the patient when confronted regarding the positive test result. Of six tests performed to ‘confirm a positive urine alcohol' two were positive for EtG and confirmed positive by self reported drinking. For the other four samples, especially as two are from a diabetic, in vitro fermentation of ethanol is discussed. Conclusions: These data suggest that physicians in monitoring programs have a higher rate of unrecognized alcohol use than previously reported. Incorporation of EtG testing into alcohol abstinence monitoring can strengthen these program

Solvent-Driven Supramolecular Wrapping of Self-Assembled Structures

Self‐assembly relies on the ability of smaller and discrete entities to spontaneously arrange into more organized systems by means of the structure‐encoded information. Herein, we show that the design of the media can play a role even more important than the chemical design. The media not only determines the self‐assembly pathway at a single‐component level, but in a very narrow solvent composition, a supramolecular homo‐aggregate can be non‐covalently wrapped by a second component that possesses a different crystal lattice. Such a process has been followed in real time by confocal microscopy thanks to the different emission colors of the aggregates formed by two isolated PtII complexes. This coating is reversible and controlled by the media composition. Single‐crystal X‐ray diffraction and molecular simulations based on coarse‐grained (CG) models allowed the understanding of the properties displayed by the different aggregates. Such findings could result in a new method to construct hierarchical supramolecular structures

Solvent-Driven Supramolecular Wrapping of Self-Assembled Structures

Self-assembly relies on the ability of smaller and discrete entities to spontaneously arrange into more organized systems by means of the structure-encoded information. Herein, we show that the design of the media can play a role even more important than the chemical design. The media not only determines the self-assembly pathway at a single-component level, but in a very narrow solvent composition, a supramolecular homo-aggregate can be non-covalently wrapped by a second component that possesses a different crystal lattice. Such a process has been followed in real time by confocal microscopy thanks to the different emission colors of the aggregates formed by two isolated PtII complexes. This coating is reversible and controlled by the media composition. Single-crystal X-ray diffraction and molecular simulations based on coarse-grained (CG) models allowed the understanding of the properties displayed by the different aggregates. Such findings could result in a new method to construct hierarchical supramolecular structures

Strong quantum memory at resonant Fermi edges revealed by shot noise

Studies of non-equilibrium current fluctuations enable assessing correlations involved in quantum transport through nanoscale conductors. They provide additional information to the mean current on charge statistics and the presence of coherence, dissipation, disorder, or entanglement. Shot noise, being a temporal integral of the current autocorrelation function, reveals dynamical information. In particular, it detects presence of non-Markovian dynamics, i.e., memory, within open systems, which has been subject of many current theoretical studies. We report on low-temperature shot noise measurements of electronic transport through InAs quantum dots in the Fermi-edge singularity regime and show that it exhibits strong memory effects caused by quantum correlations between the dot and fermionic reservoirs. Our work, apart from addressing noise in archetypical strongly correlated system of prime interest, discloses generic quantum dynamical mechanism occurring at interacting resonant Fermi edges.Comment: 6 pages, 3 figure

CONCENTRATION OF FATTY ACID ETHYL ESTERS IN HAIR OF ALCOHOLICS: COMPARISON TO OTHER BIOLOGICAL STATE MARKERS AND SELF REPORTED-ETHANOL INTAKE

Aims: In a variety of clinical and forensic situations long term use of alcohol must be monitored. In this project we explore the utility of fatty acid ethyl esters (FAEE) in this regard. Additionally, we propose a cut-off value of FAEE to distinguish teetotallers/moderate/social drinkers from alcoholics or individuals drinking at harmful levels. Patients and methods: FAEE levels from 18 alcohol-dependent patients in detoxification were contrasted with those of 10 social drinkers and 10 teetotallers. FAEE in hair were determined, using headspace solid phase microextraction and gas chromatography mass spectrometry. CFAEE, as sum of the concentrations of four esters, was compared to a major FAEE, ethyl palmitate. PEth was measured in heparinized whole blood with a high pressure liquid chromatography (HPLC) method. Drinking validation criteria include self reports, phosphatidyl ethanol (PEth) in whole blood as well as the traditional markers of heavy drinking, gamma glutamyl transpeptidase (GGT), mean corpuscular volume (MCV) and carbohydrate deficient transferrin (CDT). Results: Receiver-operating characteristic (ROC) curve analysis for CFAEE, indicated a sensitivity of 100% and a specificity of 90% for a cut-off of 0.29 ng/mg. By using a cut-off of 0.4 ng/mg, CFAEE identified 94.4% correctly. CFAEE and ethyl palmitate were significantly associated (r = 0.945; P < 0.001) as were CFAEE and PEth (r = 0.527; P = 0.025). No significant correlation was found between CFAEE and total grams of ethanol consumed last month, blood-alcohol concentration at admission to the hospital, CDT, MCV, or GGT. Among the serum and blood markers, %CDT identified 47.1%, MCV 38.8% and GGT 72.2% of patients with chronic intake of higher amounts of ethanol correctly, whereas PEth achieved 100% accuracy. Conclusions: The data suggest that CFAEE is a potentially valuable marker of chronic intake of high quantities of ethanol. Furthermore, the results indicate that a reasonable and provisional FAEE cut-off to distinguish between social/moderate and heavy drinking/alcoholism in hair is 0.4 ng/m

Zebrafish reward mutants reveal novel transcripts mediating the behavioral effects of amphetamine

Transcriptome analysis of a zebrafish mutant that does not respond to amphetamine identifies a network of coordinated gene regulation that may underlie the susceptibility to addiction