EXPERIMENTAL EVALUATION OF MODIFIED PHASE TRANSFORM FOR SOUND SOURCE DETECTION

The detection of sound sources with microphone arrays can be enhanced through processing individual microphone signals prior to the delay and sum operation. One method in particular, the Phase Transform (PHAT) has demonstrated improvement in sound source location images, especially in reverberant and noisy environments. Recent work proposed a modification to the PHAT transform that allows varying degrees of spectral whitening through a single parameter, andamp;acirc;, which has shown positive improvement in target detection in simulation results. This work focuses on experimental evaluation of the modified SRP-PHAT algorithm. Performance results are computed from actual experimental setup of an 8-element perimeter array with a receiver operating characteristic (ROC) analysis for detecting sound sources. The results verified simulation results of PHAT- andamp;acirc; in improving target detection probabilities. The ROC analysis demonstrated the relationships between various target types (narrowband and broadband), room reverberation levels (high and low) and noise levels (different SNR) with respect to optimal andamp;acirc;. Results from experiment strongly agree with those of simulations on the effect of PHAT in significantly improving detection performance for narrowband and broadband signals especially at low SNR and in the presence of high levels of reverberation

Photoinduced electron transfer between a donor and an acceptor separated by a capsular wall

The efficient photoinduced electron transfer from a stilbene derivative incarcerated within a negatively charged organic nanocapsule to positively charged acceptors (methyl viologen and a pyridinium salt) adsorbed outside and the back electron transfer were controlled by supramolecular effects

Retinal Organoids derived from hiPSCs of an AIPL1-LCA Patient Maintain Cytoarchitecture despite Reduced levels of Mutant AIPL1

Aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) is a photoreceptor-specific chaperone that stabilizes the effector enzyme of phototransduction, cGMP phosphodiesterase 6 (PDE6). Mutations in the AIPL1 gene cause a severe inherited retinal dystrophy, Leber congenital amaurosis type 4 (LCA4), that manifests as the loss of vision during the first year of life. In this study, we generated three-dimensional (3D) retinal organoids (ROs) from human induced pluripotent stem cells (hiPSCs) derived from an LCA4 patient carrying a Cys89Arg mutation in AIPL1. This study aimed to (i) explore whether the patient hiPSC-derived ROs recapitulate LCA4 disease phenotype, and (ii) generate a clinically relevant resource to investigate the molecular mechanism of disease and safely test novel therapies for LCA4 in vitro. We demonstrate reduced levels of the mutant AIPL1 and PDE6 proteins in patient organoids, corroborating the findings in animal models; however, patient-derived organoids maintained retinal cell cytoarchitecture despite significantly reduced levels of AIPL1.This work was supported by Institute of Health Carlos III (ISCIII)/ ERDF (European Research Development Fund), Spain, ((PI16/00409 (DL); DL, AAC, and SE are members of PRB3 supported by a grant (PT17/0019/0024) of the PE I + D + i 2013–2016, funded by ISCIII and ERDF. The work was also supported by ISCIII-ERDF (PI16/00425), CIBERER 06/07/0036, IIS-FJD Biobank PT13/0010/0012, RAREGENOMICS funded by Regional Government of Madrid, (CAM, B2017/BMD3721) and ERDF, the University Chair UAM-IIS-FJD of Genomic Medicine, the Spanish National Organization of the Blind (ONCE), the Spanish Fighting Blindness Foundation (FUNDALUCE), and the Ramon Areces Foundation. MC is supported by the Miguel Servet Program (CPII17_00006) from ISCIII. DL is supported by Miguel Servet I Program (CP18/00033). VR is supported by National Institute of Health (R01 EY028035, R01 EY025536). Transcriptome profiling and analyses were supported by the Intramural Research Program of the National Eye Institute (ZIAEY000450, ZIAEY000474) and utilized the high-performance computational capabilities of the Biowulf Linux cluster at NIH (http://biowulf.nih.gov)

Role of free space and weak interactions on geometric isomerization of stilbenes held in a molecular container

Photochemical geometric isomerization of olefins is long known to depend on the medium in which it occurs. Highest selectivity occurs in flexible biological systems as well as in inflexible crystals. We present results in this report that suggest the isomerization is selective even in an isotropic flexible aqueous medium provided it occurs within an isolated water-soluble inflexible reaction cavity. By examining the photochemistry of twelve stilbenes (trans and corresponding cis isomers) included in an organic cavitand octa acid we have been able to probe the role of 'free volume', 'weak interactions' and 'supramolecular steric effects' on the geometric isomerization process. Geometric isomerization becomes selective when the olefin's mobility is restricted by the medium through weak interactions, supramolecular steric effects and controlled free space (free volume)

Chemistry in restricted spaces: select photodimerizations in cages, cavities, and capsules

Carrying out chemical transformations under environmentally sustainable conditions has become one of the important current goals of chemistry. In this context, conducting reactions under solvent-free conditions (crystals, zeolites, clay, etc.) and in water has attracted considerable attention. Since most molecules either do not crystallize and or do not dissolve in water, the two approaches are complimentary. To make molecules solubilize in water one needs to employ water-soluble hosts such as micelles, cavitands, and capsules. To achieve selectivity, one should provide a confined environment within which the motions of reactant molecules are restricted to that in free solution. The confined space in which the reaction takes place independent of the host environment could be defined in terms of the "reaction cavity" originally presented by Cohen and Schmidt. In this mini-review, examples of photodimerization of olefins carried out in cavitands such as cucurbiturils, cyclodextrins, calixarenes, and octa acid are presented. Results are discussed in terms of the reaction cavity concept, which is applicable to reactions in both solids and water