5,045 research outputs found
William Arbuthnot Lane (1856-1943): Surgical Innovator and His Theory of Autointoxication.
William Arbuthnot Lane contributed to the advancement of many fields of orthopedics, otolaryngology, and general surgery. He is credited for his no-touch technique and the invention of long-handled instruments, some of which are still in use today, to minimize tissue handling. He is most well known for his hypothesis that slowing of gastric contents could cause a variety of ailments and this became known as Lane\u27s disease. Although his surgical treatment of Lane\u27s disease is now defunct, it advanced the surgical technique in colorectal surgery. It seems likely that some of Lane\u27s autointoxication patients would be classified today as patients with colonic inertia, diverticulitis, colonic volvulus, and megacolon or, which are all treated with colectomy. Lane was a pioneer in multiple fields and a true general surgeon. He advanced colorectal surgery immensely and propelled the field of surgery into a new era
1/4 is the new 1/2: Interaction-induced Unification of Quantum Anomalous and Spin Hall Effects
We introduce interactions into two general models for quantum spin Hall
physics. Although the traditional picture is that such physics appears when the
two lower spinful bands are occupied, that is, half-filling, we show using
determinantal quantum Monte Carlo as well as from an exactly solvable model
that in the presence of strong interactions, the quarter-filled state instead
exhibits the quantum spin Hall effect at high temperature. A topological Mott
insulator is the underlying cause. The peak in the spin susceptibility is
consistent with a possible ferromagnetic state at . The onset of such
magnetism would convert the quantum spin Hall to a quantum anomalous Hall
effect. We argue that it is the consistency with the Lieb-Schultz-Mattis
theorem\cite{lsm1,lsm2} for interacting systems with an odd number of charges
per unit cell that underlies the emergence of the quantum anomalous Hall effect
as a low-temperature symmetry-broken phase of the quantum spin Hall effect.
While such a symmetry-broken phase typically is accompanied by a gap, we find
that the interaction strength must exceed a critical value for the gap to form
using quantum Monte Carlo dynamical cluster approximation simulations. Hence,
we predict that topology can obtain in a gapless phase but only in the presence
of interactions in dispersive bands. These results are applied to recent
experiments on moir\'e systems and shown to be consistent with valley-coherent
quantum anomalous Hall physics.Comment: Figure 4e,f added as well as a referenc
Serologic and Hematologic Values of Bison in Colorado
Recent economic and aesthetic interest in North American bison (Bison bison) has lead to increased interstate transport of these animals. Serologic and hematologic standards for bison are needed to detect disease in transported animals as well as within herds. This paper describes variation in blood physiological parameters in bison caused by variations in diet and season. Blood was taken from six bison and analyzed for serologic and hematologic parameters. Significant variation was found in blood urea nitrogen, chloride, cholesterol, creatinine, eosinophil, glucose, hemoglobin, lactic dehydrogenase, leukocyte, packed cell volume, potassium, serum globulin, serum glutamic oxalacetic transaminase, SGPT, and sodium levels between animals receiving a high energy-high nitrogen diet and animals receiving a low energy-low nitrogen diet
Age Differences in Gaze Following : Older Adults Follow Gaze More than Younger Adults When free-viewing Scenes
Acknowledgements We thank Teodor Nikolov, Igne Umbrasaite, Bianca Bianciardi, Sarah Kenny, and Vestina Sciaponaite for assistance with stimuli selection and data collection. Funding details This research was supported by Grant RG14082 from the Economic and Social Research Council, awarded to Louise H. Phillips, Benjamin W. Tatler and Julie HenryPeer reviewedPostprin
Partial and Entropic Information Decompositions of a Neuronal Modulatory Interaction
Information processing within neural systems often depends upon selective amplification of relevant signals and suppression of irrelevant signals. This has been shown many times by studies of contextual effects but there is as yet no consensus on how to interpret such studies. Some researchers interpret the effects of context as contributing to the selective receptive field (RF) input about which neurons transmit information. Others interpret context effects as affecting transmission of information about RF input without becoming part of the RF information transmitted. Here we use partial information decomposition (PID) and entropic information decomposition (EID) to study the properties of a form of modulation previously used in neurobiologically plausible neural nets. PID shows that this form of modulation can affect transmission of information in the RF input without the binary output transmitting any information unique to the modulator. EID produces similar decompositions, except that information unique to the modulator and the mechanistic shared component can be negative when modulating and modulated signals are correlated. Synergistic and source shared components were never negative in the conditions studied. Thus, both PID and EID show that modulatory inputs to a local processor can affect the transmission of information from other inputs. Contrary to what was previously assumed, this transmission can occur without the modulatory inputs becoming part of the information transmitted, as shown by the use of PID with the model we consider. Decompositions of psychophysical data from a visual contrast detection task with surrounding context suggest that a similar form of modulation may also occur in real neural systems
Single-dose pharmacokinetic and toxicity analysis of pyrrole–imidazole polyamides in mice
Purpose:
Pyrrole–imidazole (Py-Im) polyamides are programmable, sequence-specific DNA minor groove–binding ligands. Previous work in cell culture has shown that various polyamides can be used to modulate the transcriptional programs of oncogenic transcription factors. In this study, two hairpin polyamides with demonstrated activity against androgen receptor signaling in cell culture were administered to mice to characterize their pharmacokinetic properties.
Methods:
Py-Im polyamides were administered intravenously by tail vein injection. Plasma, urine, and fecal samples were collected over a 24-h period. Liver, kidney, and lung samples were collected postmortem. Concentrations of the administered polyamide in the plasma, excretion, and tissue samples were measured using LC/MS/MS. The biodistribution data were analyzed by both non-compartmental and compartmental pharmacokinetic models. Animal toxicity experiments were also performed by monitoring weight loss after a single subcutaneous (SC) injection of either polyamide.
Results:
The biodistribution profiles of both compounds exhibited rapid localization to the liver, kidneys, and lungs upon injection. Plasma distribution of the two compounds showed distinct differences in the rate of clearance, the volume of distribution, and the AUCs. These two compounds also have markedly different toxicities after SC injection in mice.
Conclusions:
The variations in pharmacokinetics and toxicity in vivo stem from a minor chemical modification that is also correlated with differing potency in cell culture. The results obtained in this study could provide a structural basis for further improvement of polyamide activity both in cell culture and in animal models
Selective effects of 5-HT2C receptor modulation on performance of a novel valence-probe visual discrimination task and probabilistic reversal learning in mice.
RATIONALE: Dysregulation of the serotonin (5-HT) system is a pathophysiological component in major depressive disorder (MDD), a condition closely associated with abnormal emotional responsivity to positive and negative feedback. However, the precise mechanism through which 5-HT tone biases feedback responsivity remains unclear. 5-HT2C receptors (5-HT2CRs) are closely linked with aspects of depressive symptomatology, including abnormalities in reinforcement processes and response to stress. Thus, we aimed to determine the impact of 5-HT2CR function on response to feedback in biased reinforcement learning. METHODS: We used two touchscreen assays designed to assess the impact of positive and negative feedback on probabilistic reinforcement in mice, including a novel valence-probe visual discrimination (VPVD) and a probabilistic reversal learning procedure (PRL). Systemic administration of a 5-HT2CR agonist and antagonist resulted in selective changes in the balance of feedback sensitivity bias on these tasks. RESULTS: Specifically, on VPVD, SB 242084, the 5-HT2CR antagonist, impaired acquisition of a discrimination dependent on appropriate integration of positive and negative feedback. On PRL, SB 242084 at 1 mg/kg resulted in changes in behaviour consistent with reduced sensitivity to positive feedback. In contrast, WAY 163909, the 5-HT2CR agonist, resulted in changes associated with increased sensitivity to positive feedback and decreased sensitivity to negative feedback. CONCLUSIONS: These results suggest that 5-HT2CRs tightly regulate feedback sensitivity bias in mice with consequent effects on learning and cognitive flexibility and specify a framework for the influence of 5-HT2CRs on sensitivity to reinforcement
Particle-hole asymmetric ferromagnetism and spin textures in the triangular Hubbard-Hofstadter model
In a lattice model subject to a perpendicular magnetic field, when the
lattice constant is comparable to the magnetic length, one enters the
"Hofstadter regime," where continuum Landau levels become fractal magnetic
Bloch bands. Strong mixing between bands alters the nature of the resulting
quantum phases compared to the continuum limit; lattice potential, magnetic
field, and Coulomb interaction must be treated on equal footing. Using
determinant quantum Monte Carlo (DQMC) and density matrix renormalization group
(DMRG) techniques, we study this regime numerically in the context of the
Hubbard-Hofstadter model on a triangular lattice. In the field-filling phase
diagram, we find a broad wedge-shaped region of ferromagnetic ground states for
filling factor , bounded by incompressible states at filling
factor . For magnetic field strengths , we
observe signatures of SU(2) quantum Hall ferromagnetism in the lowest magnetic
Bloch band; however, we find no numerical evidence for conventional quantum
Hall skyrmions. At large fields , above the
ferromagnetic wedge, we observe a low-spin metallic region with spin
correlations peaked at small momenta. We argue that the phenomenology of this
region likely results from exchange interaction mixing fractal Hofstadter
subbands. The phase diagram derived beyond the continuum limit points to a rich
landscape to explore interaction effects in magnetic Bloch bands.Comment: 15 pages, 15 figure
Schottky-based band lineups for refractory semiconductors
An overview is presented of band alignments for small-lattice parameter, refractory semiconductors. The band alignments are estimated empirically through the use of available Schottky barrier height data, and are compared to theoretically predicted values. Results for tetrahedrally bonded semiconductors with lattice constant values in the range from C through ZnSe are presented. Based on the estimated band alignments and the recently demonstrated p-type dopability of GaN, we propose three novel heterojunction schemes which seek to address inherent difficulties in doping or electrical contact to wide-gap semiconductors such as ZnO, ZnSe, and ZnS
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