An Infrared Imaging Method for High-Throughput Combinatorial Investigation of Hydrogenation-Dehydrogenation and New Phase Formation of Thin Films

We have developed an infrared imaging setup enabling in situ infrared images to be acquired, and expanded on capabilities of an infrared imaging as a high-throughput screening technique, determination of a critical thickness of a Pd capping layer which significantly blocks infrared emission from below, enhancement of sensitivity to hydrogenation and dehydrogenation by normalizing raw infrared intensity of a Mg thin film to an inert reference, rapid and systematic screening of hydrogenation and dehydrogenation properties of a Mg–Ni composition spread covered by a thickness gradient Pd capping layer, and detection of formation of a Mg2Si phase in a Mg thin film on a thermally oxidized Si substrate during annealing

The Influence of Dormitory Architecture On Resident Behavior

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66943/2/10.1177_001391657300500402.pd

Efficacy and Safety of Intravitreal Gene Therapy for Leber Hereditary Optic Neuropathy Treated within 6 Months of Disease Onset

Purpose: To evaluate the efficacy of a single intravitreal injection of rAAV2/2-ND4 in subjects with visual loss from Leber hereditary optic neuropathy (LHON). Design: RESCUE is a multicenter, randomized, double-masked, sham-controlled, phase 3 clinical trial. Participants: Subjects with the m.11778G>A mitochondrial DNA mutation and vision loss ≤6 months from onset in 1 or both eyes were included. Methods: Each subject's right eye was randomly assigned (1:1) to treatment with rAAV2/2-ND4 (single injection of 9 × 1010 viral genomes in 90 μl) or to sham injection. The left eye received the treatment not allocated to the right eye. Main Outcome Measures: The primary end point was the difference of the change from baseline in best-corrected visual acuity (BCVA) between rAAV2/2-ND4–treated and sham-treated eyes at week 48. Other outcome measures included contrast sensitivity, Humphrey visual field perimetry, retinal anatomic measures, and quality of life. Follow-up extended to week 96. Results: Efficacy analysis included 38 subjects. Mean age was 36.8 years, and 82% were male. Mean duration of vision loss at time of treatment was 3.6 months and 3.9 months in the rAAV2/2-ND4–treated eyes and sham-treated eyes, respectively. Mean baseline logarithm of the minimum angle of resolution (logMAR) BCVA (standard deviation) was 1.31 (0.52) in rAAV2/2-ND4–treated eyes and 1.26 (0.62) in sham-treated eyes, with a range from −0.20 to 2.51. At week 48, the difference of the change in BCVA from baseline between rAAV2/2-ND4–treated and sham-treated eyes was −0.01 logMAR (P = 0.89); the primary end point of a −0.3 logMAR (15-letter) difference was not met. The mean BCVA for both groups deteriorated over the initial weeks, reaching the worst levels at week 24, followed by a plateau phase until week 48, and then an improvement of +10 and +9 Early Treatment Diabetic Retinopathy Study letters equivalent from the plateau level in the rAAV2/2-ND4–treated and sham-treated eyes, respectively. Conclusions: At 96 weeks after unilateral injection of rAAV2/2-ND4, LHON subjects carrying the m.11778G>A mutation treated within 6 months after vision loss achieved comparable visual outcomes in the injected and uninjected eyes

Predicting Solar Cell Performance from Terahertz and Microwave Spectroscopy

Mobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model the current voltage characteristics of a solar cell from such measurements. To this end, the impact of measurement conditions, alternate interpretations, and experimental inter laboratory variations are discussed using a Cs,FA,MA Pb I,Br 3 halide perovskite thin film as a case study. At 1 sun equivalent excitation, neither transport nor recombination is significantly affected by exciton formation or trapping. Terahertz, microwave, and photoluminescence transients for the neat material yield consistent effective lifetimes implying a resistance free JV curve with a potential power conversion efficiency of 24.6 . For grainsizes above amp; 8776;20 nm, intra grain charge transport is characterized by terahertz sum mobilities of amp; 8776;32 cm2 V amp; 8722;1 s amp; 8722;1. Drift diffusion simulations indicate that these intra grain mobilities can slightly reduce the fill factor of perovskite solar cells to 0.82, in accordance with the best realized devices in the literature. Beyond perovskites, this work can guide a highly predictive characterization of any emerging semiconductor for photovoltaic or photoelectrochemical energy conversion. A best practice for the interpretation of terahertz and microwave measurements on photovoltaic materials is presente

Ultrafast transient THz spectroscopy of azobenzene

Ultrafast optical pump-THz probe experiments conducted to study photo-reactive molecular systems will be presented after a brief methodology overview. Large differences in UV excitation and THz absorption cross-sections make these pump-probe investigations extremely difficult. This study concentrates on transient dynamics of trans-cis-trans isomerization of azobenzene in the liquid and solid phase

TRANSTENT GRATING SPECTROSCOPY USING THE PHASE CONJUCATE CONFIGURATION

Author Institution: Department of Chemistry and Laboratory for the Research on the Structure of Metter, University of PennsylvaniaThe picosecond time dependence of a specific nonlinear signal generated in the fully resonant and degenerate phase conjugate configuration is presented. This particular Fourier component was explored in a previous nonlinear optical mixing experiment (H. Souma, E.J.Heilweil, R.M. Hochstrasser, J. Chem, Phys. 76(12), 5693, 1982) where it was found to contain both electronic and therrmal relaxation contributions. These portions are clearly time resolved in the present study where features arising from optical mixing and subsequent thermal grating formation and decay are exhibited. Experiments performed on the dyes Rhodamine 60 and Cresy1 Violet in ethanol as well as aqueous colloidal gold solutions will be discussed. Nonradiative energy deposition of heat into the solvent by excited state vibrational energy relaxation and thermal conduction from transiently cooling metal spheres is demonstrated by these systems

Terahertz spectroscopy of dicyanobenzenes: Anomalous absorption intensities and spectral calculations

Terahertz absorption spectra of three isomeric structures of dicyanobenzene in chloroform solution and solid phase at 298 K are reported. These spectra exhibit enhanced absorption in low THz range compared to most organic systems because of strong coupling to phonon modes. Molecular vibrational spectral calculations show strong correlation with the experiment especially for solution spectra. All intramolecular modes were assigned and intermolecular modes identified. Out-of-plane intramolecular modes at low frequency exhibit similar to 75 cm(-1) blue shifts as the secondary CN group moves from the para to ortho position on the benzene ring, whereas almost no frequency shift occurs for low-frequency in-plane modes

DIRECT OBSERVATION OF INTERMOLECULAR ENERGY REDISTRIBUTION IN p-DIFLUOROBENZENE BY PICOSECOND GATING

Author Institution: Department of Chemistry, University of Pennsylvania PhiladelphiaResults are presented on the picosecond time evolution of the fluorescence spectrum of p-difluorobenzene under collision free circumstances. Time-resolved single vibronic level emission spectra were obtained by the technique of frequency down-coversion by non-linear mixing of the molecular fluorescence with a picosecond laser pulse in a non-linear gating crystal. High resolution down-coverted spectra were obtained by using a monochromator and photo-multiplier tube; lower resolution down-converted spectra were obtained by using a spectrograph and a reticon array-based optical multichannel analyzer system. The time gated spectra consisted of structured emission corresponding to vibronic transitions superimposed on a diffuse background. The diffuse background displayed a time evolution that differed from that of the structured region of the spectrum. The observed kinetics might mean that intramolecular rovibrational energy redistribution is occuring on a timescale of ca. 6 ps