120 research outputs found
Recent Advances in Understanding the Microbiology of the Female Reproductive Tract and the Causes of Premature Birth
Data derived from molecular microbiological investigations of the human vagina have led to the discovery of resident bacterial communities that exhibit marked differences in terms of species composition. All undergo dynamic changes that are likely due to intrinsic host and behavioral factors. Similar types of bacteria have been found in both amniotic fluid and the vagina, suggesting a potential route of colonization. Given that not all of the species involved in intrauterine infections are readily cultivated, it is important that culture-independent methods of analysis must be used to understand the etiology of these infections. Further research is needed to establish whether an ascending pathway from the vagina to the amniotic cavity enables the development of intrauterine infections
Changing practices: The specialised domestic violence court process
Specialised domestic violence courts, initially developed in the United States of America, have been recognised by other jurisdictions including Canada, Australia and the United Kingdom. This article presents a case study of K Court in Toronto, drawing upon documentary evidence, direct observations and interviews with key informants. It is argued that the specialised domestic violence court process includes changing practices of some of the key stakeholders. Learning lessons from abroad can offer jurisdictions insights that can steer implementation of appropriate practices in the field
Atomically Resolved Imaging of Highly Ordered Alternating Fluorinated Graphene
One of the most desirable goals of graphene research is to produce ordered 2D
chemical derivatives of suitable quality for monolayer device fabrication. Here
we reveal, by focal series exit wave reconstruction, that C2F chair is a stable
graphene derivative and demonstrates pristine long-range order limited only by
the size of a functionalized domain. Focal series of images of graphene and C2F
chair formed by reaction with XeF2 were obtained at 80 kV in an
aberration-corrected transmission electron microscope. EWR images reveal that
single carbon atoms and carbon-fluorine pairs in C2F chair alternate strictly
over domain sizes of at least 150 nm^2 with electron diffraction indicating
ordered domains >/= 0.16 square micrometer. Our results also indicate that,
within an ordered domain, functionalization occurs on one side only as theory
predicts. Additionally we show that electron diffraction provides a quick and
easy method for distinguishing between graphene, C2F chair and fully
fluorinated stoichiometric CF 2D phases
Ultra-High Carrier Mobilities in Ferroelectric Domain Wall Corbino Cones at Room Temperature
Recently, electrically conducting heterointerfaces between dissimilar band-insulators (such as lanthanum aluminate and strontium titanate) have attracted considerable research interest. Charge transport has been thoroughly explored and fundamental aspects of conduction firmly established. Perhaps surprisingly, similar insights into conceptually much simpler conducting homointerfaces, such as the domain walls that separate regions of different orientations of electrical polarisation within the same ferroelectric band-insulator, are not nearly so well-developed. Addressing this disparity, we herein report magnetoresistance in approximately conical 180° charged domain walls, which occur in partially switched ferroelectric thin film single crystal lithium niobate. This system is ideal for such measurements: firstly, the conductivity difference between domains and domain walls is extremely and unusually large (a factor of at least 1013) and hence currents driven through the thin film, between planar top and bottom electrodes, are overwhelmingly channelled along the walls; secondly, when electrical contact is made to the top and bottom of the domain walls and a magnetic field is applied along their cone axes (perpendicular to the thin film surface), then the test geometry mirrors that of a Corbino disc, which is a textbook arrangement for geometric magnetoresistance measurement. Our data imply carriers at the domain walls with extremely high room temperature Hall mobilities of up to ~ 3,700cm2V-1s-1. This is an unparalleled value for oxide interfaces (and for bulk oxides too) and is most comparable to mobilities in other systems typically seen at cryogenic, rather than at room, temperature
Observation of Antiferroelectric Domain Walls in a Uniaxial Hyperferroelectric
Ferroelectric domain walls are a rich source of emergent electronic
properties and unusual polar order. Recent studies showed that the
configuration of ferroelectric walls can go well beyond the conventional
Ising-type structure. N\'eel-, Bloch-, and vortex-like polar patterns have been
observed, displaying strong similarities with the spin textures at magnetic
domain walls. Here, we report the discovery of antiferroelectric domain walls
in the uniaxial ferroelectric PbGeO. We resolve highly
mobile domain walls with an alternating displacement of Pb atoms, resulting in
a cyclic 180 flip of dipole direction within the wall. Density
functional theory calculations reveal that PbGeO is
hyperferroelectric, allowing the system to overcome the depolarization fields
that usually suppress antiparallel ordering of dipoles along the longitudinal
direction. Interestingly, the antiferroelectric walls observed under the
electron beam are energetically more costly than basic head-to-head or
tail-to-tail walls. The results suggest a new type of excited domain-wall
state, expanding previous studies on ferroelectric domain walls into the realm
of antiferroic phenomena
Graphene re-knits its holes
Nano-holes, etched under an electron beam at room temperature in singlelayer
graphene sheets as a result of their interaction with metalimpurities, are
shown to heal spontaneously by filling up with either non-hexagon,
graphene-like, or perfect hexagon 2D structures. Scanning transmission electron
microscopy was employed to capture the healing process and study atom-by-atom
the re-grown structure. A combination of these nano-scale etching and
re-knitting processes could lead to new graphene tailoring approaches.Comment: 11 pages, 4 figure
Efficient N-Type Organic Electrochemical Transistors and Field-Effect Transistors Based on PNDI-Copolymers Bearing Fluorinated Selenophene-Vinylene-Selenophenes
n-Type organic electrochemical transistors (OECTs) and organic field-effect transistors (OFETs) are less developed than their p-type counterparts. Herein, polynaphthalenediimide (PNDI)-based copolymers bearing novel fluorinated selenophene-vinylene-selenophene (FSVS) units as efficient materials for both n-type OECTs and n-type OFETs are reported. The PNDI polymers with oligo(ethylene glycol) (EG7) side chains P(NDIEG7-FSVS), affords a high µC* of > 0.2 F cm−1 V−1 s−1, outperforming the benchmark n-type Pg4NDI-T2 and Pg4NDI-gT2 by two orders of magnitude. The deep-lying LUMO of −4.63 eV endows P(NDIEG7-FSVS) with an ultra-low threshold voltage of 0.16 V. Moreover, the conjugated polymer with octyldodecyl (OD) side chains P(NDIOD-FSVS) exhibits a surprisingly low energetic disorder with an Urbach energy of 36 meV and an ultra-low activation energy of 39 meV, resulting in high electron mobility of up to 0.32 cm2 V−1 s−1 in n-type OFETs. These results demonstrate the great potential for simultaneously achieving a lower LUMO and a tighter intermolecular packing for the next-generation efficient n-type organic electronics
Current Account Imbalances and Structural Adjustment in the Euro Area: How to Rebalance Competitiveness
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