Multi-scale Optics for Enhanced Light Collection from a Point Source

High efficiency collection of photons emitted by a point source over a wide field-of-view (FoV) is crucial for many applications. Multi-scale optics over improved light collection by utilizing small optical components placed close to the optical source, while maintaining a wide FoV provided by conventional imaging optics. In this work, we demonstrate collection efficiency of 26% of photons emitted by a point-like source using a micromirror fabricated in silicon with no significant decrease in collection efficiency over a 10 mm object space.Comment: 4 pages, 4 figure

High-throughput three-dimensional lithographic microfabrication

A 3D lithographic microfabrication process has been developed that is high throughput, scalable, and capable of producing arbitrary patterns. It offers the possibility for industrial scale manufacturing of 3D microdevices such as photonic crystals, tissue engineering scaffolds, and microfluidics chips. This method is based on depth-resolved wide-field illumination by temporally focusing femtosecond light pulses. We characterized the axial resolution of this technique, and the result is consistent with the theoretical prediction. As proof-of-concept experiments, we demonstrated photobleaching of 3D resolved patterns in a fluorescent medium and fabricating 3D microstructures with SU-8 photoresist.Deshpande Center for Technological Innovation (Massachusetts Institute of Technology. School of Engineering)Singapore-MIT Alliance for Research and Technology (SMART

Giant magnetoelectric effect in pure manganite-manganite heterostructures

Obtaining strong magnetoelectric couplings in bulk materials and heterostructures is an ongoing challenge. We demonstrate that manganite heterostructures of the form ${\rm (Insulator)/(LaMnO_3)_n/(CaMnO_3)_n/(Insulator)}$ show strong multiferroicity in magnetic manganites where ferroelectric polarization is realized by charges leaking from ${\rm LaMnO_3}$ to ${\rm CaMnO_3}$ due to repulsion. Here, an effective nearest-neighbor electron-electron (electron-hole) repulsion (attraction) is generated by cooperative electron-phonon interaction. Double exchange, when a particle virtually hops to its unoccupied neighboring site and back, produces magnetic polarons that polarize antiferromagnetic regions. Thus a striking giant magnetoelectric effect ensues when an external electrical field enhances the electron leakage across the interface.Comment: 13 page

Deaf Children’s Science Content Learning in Direct Instruction versus Interpreted Instruction

This research study compared learning of 6-9th grade deaf students under two modes of educational delivery – interpreted vs. direct instruction using science lessons. Nineteen deaf students participated in the study in which they were taught six science lessons in American Sign Language. In one condition, the lessons were taught by a hearing teacher in English and were translated in ASL via a professional and certified interpreter. In the second condition, the lessons were taught to the students in ASL by a deaf teacher. All students saw three lessons delivered via an interpreter and three different lessons in direct ASL; the order of delivery of each presentation was counter balanced between the two groups of students. Following the instruction, each group was tested on the science lecture materials with six comprehension questions. Results indicated that deaf students who received direct instruction in ASL from the deaf teacher scored higher on content knowledge

Work-Related Resilience: Deaf Professionals’ Perspectives

Ten Deaf professionals were interviewed about their perspectives on resilience risk and protective factors that affect career success. Thematic analysis revealed four main risk factors, all related to inequalities: (a) audism and linguistism; (b) networking challenges; (c) working harder than hearing peers; and, (d) promotion limitations. The Deaf community was described as a resilience protective factor that counters the work-related risk factors because it provides: (a) social support; (b) role models; and, (c) “Deaf can” optimism. The results have important implications for vocational rehabilitation, education and counseling programs as they highlight the protective factors Deaf employees need for work-related resilience

The E3 ubiquitin ligase IDOL regulates synaptic ApoER2 levels and is important for plasticity and learning.

Neuronal ApoE receptors are linked to learning and memory, but the pathways governing their abundance, and the mechanisms by which they affect the function of neural circuits are incompletely understood. Here we demonstrate that the E3 ubiquitin ligase IDOL determines synaptic ApoER2 protein levels in response to neuronal activation and regulates dendritic spine morphogenesis and plasticity. IDOL-dependent changes in ApoER2 abundance modulate dendritic filopodia initiation and synapse maturation. Loss of IDOL in neurons results in constitutive overexpression of ApoER2 and is associated with impaired activity-dependent structural remodeling of spines and defective LTP in primary neuron cultures and hippocampal slices. IDOL-deficient mice show profound impairment in experience-dependent reorganization of synaptic circuits in the barrel cortex, as well as diminished spatial and associative learning. These results identify control of lipoprotein receptor abundance by IDOL as a post-transcriptional mechanism underlying the structural and functional plasticity of synapses and neural circuits

Red blood cell thermal fluctuations: comparison between experiment and molecular dynamics simulations

Copyright © 2013 Royal Society of ChemistryWe outline a new method of analysis of thermal shape fluctuations of red blood cells, based on comparison between experiments and coarse-grained molecular dynamics simulations. The fluctuations of 2D equatorial contours of red blood cells are recorded experimentally using fast phase-contrast video microscopy, from which the fluctuation spectrum is calculated. The spectrum is compared to the corresponding contour fluctuation spectrum obtained from a finite-temperature particle-dynamics simulation, modelling a cell with bending and shear elasticity and conserved volume and surface area. We demonstrate that the simulation correctly describes the mean cell shape as well as the membrane thermal fluctuations, returning physically sound values for the relevant membrane elastic moduli

miR-27a and miR-27b regulate autophagic clearance of damaged mitochondria by targeting PTEN-induced putative kinase 1 (PINK1)

Computational prediction of miRNA candidates for human PINK1. a Computation prediction of miRNAs expressed in human midbrain with putative binding sites in the 3′UTR of human PINK1 mRNA. We first searched miRNAs that have putative binding sites in the 3′UTR of human PINK1 mRNA by utilizing several miRNA-target prediction algorithms, such as miRanda [67], miRWalk [68], RNAhybrid [37], and Targetscan [69]. Among 49 miRNAs commonly predicted by different algorithms, 7 miRNAs were known to be expressed in human midbrain [34]. miR-27a/b are predicted to have 2 putative binding sites in the 3′UTR of human PINK1 mRNA, while all other miRNAs are predicted to have 1 putative binding site. b Computational binding prediction of miR-27a/b and their binding sites in the 3′UTR of human PINK1 mRNA. The binding free energies were determined by the RNAhybrid algorithm. (PDF 68 kb

Preventive measures in infancy to reduce under-five mortality: a case-control study in The Gambia.

OBJECTIVE: To investigate the relationship between child mortality and common preventive interventions: vaccination, trained birthing attendants, tetanus toxoid during pregnancy, breastfeeding and vitamin A supplementation. METHODS: Case-control study in a population under demographic surveillance. Cases (n = 141) were children under five who died. Each was age and sex-matched to five controls (n = 705). Information was gathered by interviewing primary caregivers. RESULTS: All but one of the interventions - whether the mother had received tetanus toxoid during pregnancy - were protective against child mortality after multivariate analysis. Having a trained person assisting at child birth (OR 0.2 95% CI 0.1-0.4), receiving all vaccinations by 9 months of age (OR 0.1; 95% CI 0.01-0.3), being breastfed for more than 12 months (Children breastfed between 13 and 24 months OR 0.1 95% CI 0.03-0.3, more than 25 months OR 0.1 95% CI 0.01-0.5) and receiving vitamin A supplementation at or after 6 months of age (OR 0.05; 95% CI 0.01-0.2) were protective against child death. CONCLUSIONS: This study confirms the value of at least four available interventions in the prevention of under-five death in The Gambia. It is now important to identify those who are not receiving them and why, and to intervene to improve coverage across the population