8,607 research outputs found
Dynamical reduction of the dimensionality of exchange interactions and the "spin-liquid" phase of -(BEDT-TTF)
We show that the anisotropy of the effective spin model for the dimer Mott
insulator phase of -(BEDT-TTF) salts is dramatically different
from that of the underlying tight-binding model. Intra-dimer quantum
interference results in a model of coupled spin chains, where frustrated
interchain interactions suppress long-range magnetic order. Thus, we argue, the
"spin liquid" phase observed in some of these materials is a remnant of the
Tomonaga-Luttinger physics of a single chain. This is consistent with previous
experiments and resolves some outstanding puzzles. An erratum [Phys. Rev. Lett.
120, 199901 (2018).] is added as an appendix.Comment: Accepted by PRL, 6 pages, 5 figure
Towards mechanomagnetics in elastic crystals: insights from [Cu(acac)]
We predict that the magnetic properties of \cuacac, an elastically flexible
crystal, change dramatically when the crystal is bent. We find that unbent
\cuacac\ is an almost perfect Tomonaga-Luttinger liquid. Broken-symmetry
density functional calculations reveal that the magnetic exchange interactions
along the chains is an order of magnitude larger than the interchain exchange.
The geometrically frustrated interchain interactions cannot magnetically order
the material at any experimentally accessible temperature. The ordering
temperature (), calculated from the chain random phase approximation,
increases by approximately 24 orders of magnitude when the material is bent. We
demonstrate that geometric frustration both suppresses and enhances the
sensitivity of to bending. In \cuacac, is extremely sensitive to
bending, but remains too low for practical applications, even when bent.
Partially frustrated materials could achieve the balance of high and good
sensitivity to bending required for practical applications of mechanomagnetic
elastic crystals
Redetermination of para-aminopyridine (fampridine, EL-970) at 150 K
The structure of fampridine (EL-970) or 4-aminopyridine, Câ
HâNâ, has been redetermined at 150 K. The room-temperature structure has been reported previously [Chao & Schempp (1977). Acta Cryst. B33, 1557-1564]. Pyramidalization at the amine N atom occurs in fampridine, with the N atom 0.133 (11) Ă
from the plane of the three C/H/H atoms to which it is bonded; the interplanar angle between the pyridyl ring and NH2 group is 21 (2)°. Aggregation in the solid state occurs by N-H...N and N-H...[pi](pyridine) interactions with N...N and N...[pi](centroid) distances of 2.9829 (18) and 3.3954 (15) Ă
, respectively; a C-H...[pi](pyridine) contact completes the intermolecular interactions [C...[pi](centroid) = 3.6360 (16) Ă
]
Serum N-Terminal Type III Procollagen Propeptide: An Indicator of Growth Hormone Excess and Response to Treatment in Feline Hypersomatotropism
BACKGROUND: Nâterminal type III procollagen propeptide (PIIINP) is a biomarker of soft tissue proliferation. Hypersomatotropism (HS) is associated with soft tissue proliferation. HYPOTHESIS: Serum PIIINP is increased in cats with HS and decreases with effective treatment, and may be an additional tool in the diagnosis and treatment of feline HS. ANIMALS: Cats with uncomplicated diabetes mellitus (DM; n = 30) and with HSâinduced DM (HSDM; n = 30). Preâ and posttreatment samples were available from 5 cats undergoing radiotherapy (RT) and 16 cats undergoing hypophysectomy (HPX). METHODS: Retrospective and prospective crossâsectional study. Analytical performance of a serum PIIINP ELISA was assessed and validated for use in cats. PIIINP and insulinâlike growth factor 1 (IGFâ1) radioimmunoassays (RIA) were performed preâ and postâtreatment in cats with DM and HSDM. PIIINP and IGFâ1 were compared between cats treated by RT and HPX. RESULTS: Serum PIIINP concentrations were significantly higher (P < .001) in HSDM cats (median, 19.6 ng/mL; range, 1.7â27.9) compared to DM cats (median, 5.0 ng/mL; range, 2.1â10.4). A cutâoff of 10.5 ng/mL allowed differentiation between DM and HSDM cats with 87% sensitivity and 100% specificity (area under the curve [AUC], 0.91; 95% confidence interval [CI], 0.82â1). After RT, PIIINP increased significantly (P = .043) with no significant change in IGFâ1 concentrations. After HPX, serum PIIINP (P = .034) and IGFâ1 concentrations (P < .001) decreased significantly. CONCLUSION AND CLINICAL IMPORTANCE: PIIINP concentrations are increased in cats with untreated HSDM compared to those with DM, demonstrating the effect of excess GH on soft tissue. PIIINP concentrations decreased after HPX in most HSDM cats
An investigation of children's peer trust across culture: is the composition of peer trust universal?
The components of children's trust in same-gender peers (trust beliefs, ascribed trustworthiness, and dyadic reciprocal trust) were examined in samples of 8- to 11-year-olds from the UK, Italy, and Japan. Trust was assessed by children's ratings of the extent to which same-gender classmates kept promises and kept secrets. Social relations analyses confirmed that children from each country showed significant: (a) actor variance demonstrating reliable individual differences in trust beliefs, (b) partner variance demonstrating reliable individual differences in ascribed trustworthiness, and (c ) relationship variance demonstrating unique relationships between interaction partners. Cultural differences in trust beliefs and ascribed trustworthiness also emerged and these differences were attributed to the tendency for children from cultures that value societal goals to share personal information with the peer group
Providing Diverse Trainees an Early and Transparent Introduction to Academic Appointment and Promotion Processes.
IntroductionThe growth in number of medical schools and increased numbers of faculty tracks have combined with evolving criteria for promotion to trigger a call for greater transparency of academic appointment and promotion processes. Most vulnerable to confusion about these changes are first-generation and diverse medical students and residents, the upstream pipeline of the academic medicine workforce. Diverse medical students have expressed diminished interest in academia because of perceived obstacles in appointment and promotion processes.MethodsThis workshop was designed to utilize didactics and career reflection exercises to help trainees learn: (1) how to define core terms related to academic appointment and promotion processes, (2) how to compare data elements for different CVs and portfolios, (3) common steps in submitting a promotion package, and (4) that they can immediately begin to document content for academic CVs, portfolios, and promotion packages.ResultsOne hundred forty-five diverse participants completed an evaluation at eight conferences across the U.S. More than 90% strongly agreed or agreed that the aforementioned objectives were met. Participants commented that the workshop was "illuminating," was "very informative," and "provided an inside look of how faculty are evaluated." Results showed an immediate impact on participants' self-reported confidence to negotiate appointment and promotion processes.DiscussionIncreases in self-rated confidence to negotiate appointment and promotion processes may help sustain trainees' interest in becoming future faculty. Further monitoring will be needed to determine if early exposure to these concepts improves probability of seeking, obtaining, and maintaining appointments
Large-scale and significant expression from pseudogenes in Sodalis glossinidius â a facultative bacterial endosymbiont
The majority of bacterial genomes have high coding efficiencies, but there are some genomes of intracellular bacteria that have low gene density. The genome of the endosymbiont Sodalis glossinidius contains almost 50â% pseudogenes containing mutations that putatively silence them at the genomic level. We have applied multiple âomicâ strategies, combining Illumina and Pacific Biosciences Single-Molecule Real-Time DNA sequencing and annotation, stranded RNA sequencing and proteome analysis to better understand the transcriptional and translational landscape of Sodalis pseudogenes, and potential mechanisms for their control. Between 53 and 74â% of the Sodalis transcriptome remains active in cell-free culture. The mean sense transcription from coding domain sequences (CDSs) is four times greater than that from pseudogenes. Comparative genomic analysis of six Illumina-sequenced Sodalis isolates from different host Glossina species shows pseudogenes make up ~40â% of the 2729 genes in the core genome, suggesting that they are stable and/or that Sodalis is a recent introduction across the genus Glossina as a facultative symbiont. These data shed further light on the importance of transcriptional and translational control in deciphering hostâmicrobe interactions. The combination of genomics, transcriptomics and proteomics gives a multidimensional perspective for studying prokaryotic genomes with a view to elucidating evolutionary adaptation to novel environmental niches
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