77 research outputs found
A narrative group model to reduce gender role conflict in adult males
This manuscript provides a therapeutic group model to address gender role conflict in males based on a narrative approach. The use of story telling and metaphor are central to the process because they are reflective of how men tend to communicate. This approach reflects a shift away from traditional counseling approach often seen as the antithesis of a masculine ideology. This process provides group members the opportunities to co-create and re-author socially constructed stories of masculinity and maleness that have taught males to abuse and neglect their bodies while at the same time not seek help. Unique to this model is the effort to provide empirically based outcome data on the effectiveness of the group
Hairpins in the conformations of a confined polymer
If a semiflexible polymer confined to a narrow channel bends around by 180
degrees, the polymer is said to exhibit a hairpin. The equilibrium extension
statistics of the confined polymer are well understood when hairpins are
vanishingly rare or when they are plentiful. Here we analyze the extension
statistics in the intermediate situation via experiments with DNA coated by the
protein RecA, which enhances the stiffness of the DNA molecule by approximately
one order of magnitude. We find that the extension distribution is highly
non-Gaussian, in good agreement with Monte Carlo simulations of confined
discrete wormlike chains. We develop a simple model that qualitatively explains
the form of the extension distribution. The model shows that the tail of the
distribution at short extensions is determined by conformations with one
hairpin.Comment: Revised version. 22 pages, 7 figures, 2 tables, supplementary
materia
Visualization of defect-induced excitonic properties of the edges and grain boundaries in synthesized monolayer molybdenum disulfide
Atomically thin two-dimensional (2D) transition metal dichalcogenides (TMDCs)
are attractive materials for next generation nanoscale optoelectronic
applications. Understanding nanoscale optical behavior of the edges and grain
boundaries of synthetically grown TMDCs is vital for optimizing their
optoelectronic properties. Elucidating the nanoscale optical properties of 2D
materials through far-field optical microscopy requires a diffraction-limited
optical beam diameter sub-micron in size. Here we present our experimental work
on spatial photoluminescence (PL) scanning of large size ( microns)
monolayer MoS grown by chemical vapor deposition (CVD) using a diffraction
limited blue laser beam spot (wavelength 405 nm) with a beam diameter as small
as 200 nm allowing us to probe nanoscale excitonic phenomena which was not
observed before. We have found several important features: (i) there exists a
sub-micron width strip ( nm) along the edges that fluoresces brighter than the region far inside; (ii) there is another brighter
wide region consisting of parallel fluorescing lines ending at the corners of
the zig-zag peripheral edges; (iii) there is a giant blue shifted A-excitonic
peak, as large as meV, in the PL spectra from the edges. Using
density functional theory calculations, we attribute this giant blue shift to
the adsorption of oxygen dimers at the edges, which reduces the excitonic
binding energy. Our results not only shed light on defect-induced excitonic
properties, but also offer an attractive route to tailor optical properties at
the TMDC edges through defect engineering.Comment: 10 pages, 4 figures in Journal of Physical Chemistry C, 201
Photoresponse of Natural van der Waals Heterostructures
Van der Waals (vdW) heterostructures consisting of two dimensional materials
offer a platform to obtain material by design and are very attractive owing to
novel electronic states. Research on 2D van der Waals heterostructures (vdWH)
has so far been focused on fabricating individually stacked atomically thin
unary or binary crystals. Such systems include graphene (Gr), hexagonal boron
nitride (h-BN) and member of the transition metal dichalcogenides family. Here
we present our experimental study of the opto-electronic properties of a
naturally occurring vdWH, known as Franckeite, which is a complex layered
crystal composed of lead, tin, antimony, iron and sulfur. We present here that
thin film franckeite (60 nm < d < 100 nm) behave as narrow band gap
semiconductor demonstrating a wide band photoresponse. We have observed the
band-edge transition at ~ 1500 nm (~830 meV) and high external quantum
efficiency (EQE~3%) at room temperature. Laser power resolved and temperature
resolved photocurrent measurements reveal that the photo-carrier generation and
recombination are dominated by continuously distributed trap states within the
band gap. To understand wavelength resolved photocurrent, we also calculated
the optical absorption properties via density functional theory. Finally, we
have shown that the device has fast photoresponse with rise time as fast as ~ 1
ms. Our study provides a fundamental understanding of the optoelectronic
behavior in a complex naturally occurring vdWH and can open up the
possibilities of producing new type of nanoscale optoelectronic devices with
tailored properties.Comment: 10 pages, 5 figures (to be appeared in ACS NANO
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