CaseGuide: Making Cheap Smartphones Accessible to Individuals with Visual Impairments in Informal Settlements

Individuals with visual impairments in informal settlements (IVIIS) depend highly on others for access to basic services. Smartphones can help provide assistive technology and access to basic services but are too expensive for IVIIS or lack accessibility features. This study explores and promotes a low-cost concept that uses a static interface overlay app in conjunction with a button enabled phone case, to enable the use of cheap smartphones and increase IVIIS autonomy and inclusion in society. Using existing research and an observational study of YouTube videos, design requirements were determined. A low-fidelity prototype was developed and usertested on one visually impaired and two blindfolded participants. Although usertests showed promising results, research and usertesting were limited. Future research and usertests with IVIIS are needed to validate if CaseGuide is a desirable solution for IVIIS

Spin driven emergent antiferromagnetism and metal insulator transition in nanoscale p-Si

The entanglement of the charge, spin and orbital degrees of freedom can give rise to emergent behavior especially in thin films, surfaces and interfaces. Often, materials that exhibit those properties require large spin orbit coupling. We hypothesize that the emergent behavior can also occur due to spin, electron and phonon interactions in widely studied simple materials such as Si. That is, large intrinsic spin-orbit coupling is not an essential requirement for emergent behavior. The central hypothesis is that when one of the specimen dimensions is of the same order (or smaller) as the spin diffusion length, then non-equilibrium spin accumulation due to spin injection or spin-Hall effect (SHE) will lead to emergent phase transformations in the non-ferromagnetic semiconductors. In this experimental work, we report spin mediated emergent antiferromagnetism and metal insulator transition in a Pd (1 nm)/Ni81Fe19 (25 nm)/MgO (1 nm)/p-Si (~400 nm) thin film specimen. The spin-Hall effect in p-Si, observed through Rashba spin-orbit coupling mediated spin-Hall magnetoresistance behavior, is proposed to cause the spin accumulation and resulting emergent behavior. The phase transition is discovered from the diverging behavior in longitudinal third harmonic voltage, which is related to the thermal conductivity and heat capacity.Comment: 34 pages, Physica Status Solidi B- Physics, 201

Site-Specific Metal Chelation Facilitates the Unveiling of Hidden Coordination Sites in an Fe II/Fe III -Seamed Pyrogallol[4]arene Nanocapsule

Under suitable conditions, C-alkylpyrogallol­[4]­arenes (PgCs) arrange into spherical metal–organic nanocapsules (MONCs) upon coordination to appropriate metal ions. Herein we present the synthesis and structural characterization of a novel FeII/FeIII-seamed MONC, as well as studies related to its electrochemical and magnetic behaviors. Unlike other MONCs that are assembled through 24 metal ions, this nanocapsule comprises 32 Fe ions, uncovering 8 additional coordination sites situated between the constituent PgC subunits. The FeII ions are likely formed by the reducing ability of DMF used in the synthesis, representing a novel synthetic route toward polynuclear mixed-valence MONCs

Antagonism of neurosteroid modulation of native γ-aminobutyric acid receptors by (3α,5α)-17-phenylandrost-16-en-3-ol

Endogenous pregnane neurosteroids are allosteric modulators at γ-aminobutyric acid type-A (GABAA) receptors at nanomolar concentrations. There is direct evidence for multiple distinct neurosteroid binding sites on GABAA receptors, dependent upon subunit composition and stoichiometry. This view is supported by the biphasic kinetics of various neuroactive steroids, enantioselectivity of some neurosteroids, selective mutation studies of recombinantly expressed receptors and the selectivity of the neurosteroid antagonist (3α,5α)-17-phenylandrost-16-en-3-ol (17PA) on 5α-pregnane steroid effects on recombinant GABAA receptors expressed in Xenopus oocytes and native receptors in dissociated neurons. However, it is unclear whether this antagonist action is present in a mature mammalian system. The present study evaluated the antagonist activity of 17PA on neurosteroid agonists both in vivo and in vitro by examining the effects of 17PA on 5α-pregnane-induced sedation in rats, native mature GABAA receptor ion channels utilizing the chloride flux assay and further studies in recombinant α1β2γ2 receptors. The data show that 17PA preferentially inhibits 3α,5α-THP vs. alphaxalone in vivo, preferentially inhibits 3α,5α-THDOC vs. alphaxalone potentiation of GABA-mediated Cl- uptake in adult cerebral cortical synaptoneurosomes, but shows no specificity for 3α,5α-THDOC vs. alphaxalone in recombinant α1β2γ2 receptors. These data provide further evidence of the specificity of 17PA and the heterogeneity of neurosteroid recognition sites on GABAA receptors in the CNS

Dipole Strength Distributions from HIGS Experiments

A series of photon scattering experiments has been performed on the double-beta decay partners 76Ge and 76Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesi

Structure of Uranium(V) Methyl and Uranium(IV) Ylide Complexes

Syntheses of rare examples of U(V) methyl and U(IV) ylide complexes are reported. Reaction of the previously reported U(IV) imido complex [(C 5Me 5) 2U(py)(═NMes)] (py = pyridine, and Mes = 2,4,6-Me 3C 6H 2) with CuI forms the U(V) complex [(C 5Me 5) 2U(I)(═NMes)]. Reaction of the iodo complex with MgMe 2 produces the methyl complex [(C 5Me 5) 2U(CH 3)(═NMes)]. The methyl complex was reacted with CH 2PPh 3, surprisingly forming [(C 5Me 5) 2U(CH 2PPh 3)(═NMes)], a U(IV) ylide. This is formed from a disproportionation of a transient U(V) carbene, leading to the U(IV) ylide and a U(VI) bis(imido) complex, [(C 5Me 5) 2U(═NMes) 2]. These complexes were characterized using spectroscopic methods (nuclear magnetic resonance, infrared, and ultraviolet-visible-nean infrared), SQUID magnetometry, and X-ray crystallography, and density functional theory calculations are used to compare the U(V) methyl with the targeted U(V) carbene ligands

Head Impact Exposure in Youth and Collegiate American Football

The relationship between head impact and subsequent brain injury for American football players is not well defined, especially for youth. The objective of this study is to quantify and assess Head Impact Exposure (HIE) metrics among youth and collegiate football players. This multiseason study enrolled 639 unique athletes (354 collegiate; 285 youth, ages 9–14), recording 476,209 head impacts (367,337 collegiate; 108,872 youth) over 971 sessions (480 collegiate; 491 youth). Youth players experienced 43 and 65% fewer impacts per competition and practice, respectively, and lower impact magnitudes compared to collegiate players (95th percentile peak linear acceleration (PLA, g) competition: 45.6 vs 61.9; 95th percentile PLA practice: 42.6 vs 58.8; 95th percentile peak rotational acceleration (PRA, rad∙s–2) competition: 2262 vs 4422; 95th percentile PRA practice: 2081 vs 4052; 95th percentile HITsp competition: 25.4 vs 32.8; 95th percentile HITsp practice: 23.9 vs 30.2). Impacts during competition were more frequent and of greater magnitude than during practice at both levels. Quantified comparisons of head impact frequency and magnitude between youth and collegiate athletes reveal HIE differences as a function of age, and expanded insight better informs the development of age-appropriate guidelines for helmet design, prevention measures, standardized testing, brain injury diagnosis, and recovery management