The use of the South African frog (Xenopus laevis) in the study of spinal reflex physiology

The use of the South African frog (Xenopus laevis) in studies on spinal neurophysiology is introduced for the study of monosynaptic reflexes. Motorneurone excitability in this species may be measured by the classical procedure of monosynaptic testing. Operational procedures for exposing the spinal cord and the roots of the spinal nerves are described. Detailed information on stimulating and recording techniques which have been found satisfactory for the South African frog are given.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The association of dietary choline and betaine with the risk of type 2 diabetes: The atherosclerosis risk in communities (aric) study

OBJECTIVE To examine the association between dietary intake of choline and betaine and the risk of type 2 diabetes. RESEARCH DESIGN AND METHODS Among 13,440 Atherosclerosis Risk in Communities (ARIC) study participants, the prospective longitudinal association between dietary choline and betaine intake and the risk of type 2 diabetes was assessed using interval-censored Cox pro-portional hazards and logistic regression models adjusted for baseline potential confounding variables. RESULTS Among 13,440 participants (55% women, mean age 54 [SD 7.4] years), 1,396 developed incident type 2 diabetes during median follow-up of 9 years from 1987 to 1998. There was no statistically significant association between every 1-SD increase in dietary choline and risk of type 2 diabetes (hazard ratio [HR] 1.01 [95% CI 0.87, 1.16]) nor between dietary betaine intake and the risk of type 2 diabetes (HR 1.01 [0.94, 1.10]). Those in the highest quartile of dietary choline intake did not have a statistically significant higher risk of type 2 diabetes than those in the lowest choline quartile (HR 1.09 [0.84, 1.42]); similarly, dietary betaine intake was not associated with the risk of type 2 diabetes comparing the highest quartile to the lowest (HR 1.06 [0.87, 1.29]). Among women, there was a higher risk of type 2 diabetes, comparing the highest to lowest dietary choline quartile (HR 1.54 [1.06, 2.25]), while in men, the association was null (HR 0.82 [0.57, 1.17]). Nevertheless, there was a nonsignificant interaction between high choline intake and sex on the risk of type 2 diabetes (P 5 0.07). The results from logistic regression were similar. CONCLUSIONS Overall and among male participants, dietary choline or betaine intakes were not associated with the risk of type 2 diabetes. Among female participants, there was a trend for a modestly higher risk of type 2 diabetes among those with the highest as compared with the lowest quartile of dietary choline intake. Our study should inform clinical trials on dietary choline and betaine supplementation in relationship with the risk of type 2 diabetes

Scale-free static and dynamical correlations in melts of monodisperse and Flory-distributed homopolymers: A review of recent bond-fluctuation model studies

It has been assumed until very recently that all long-range correlations are screened in three-dimensional melts of linear homopolymers on distances beyond the correlation length $\xi$ characterizing the decay of the density fluctuations. Summarizing simulation results obtained by means of a variant of the bond-fluctuation model with finite monomer excluded volume interactions and topology violating local and global Monte Carlo moves, we show that due to an interplay of the chain connectivity and the incompressibility constraint, both static and dynamical correlations arise on distances $r \gg \xi$. These correlations are scale-free and, surprisingly, do not depend explicitly on the compressibility of the solution. Both monodisperse and (essentially) Flory-distributed equilibrium polymers are considered.Comment: 60 pages, 49 figure

Experimental Facilities Development

This research was sponsored by the National Science Foundation Grant NSF PHy 87-1440

C9ORF72 patient-derived endothelial cells drive blood-brain barrier disruption and contribute to neurotoxicity

The blood-brain barrier (BBB) serves as a highly intricate and dynamic interface connecting the brain and the bloodstream, playing a vital role in maintaining brain homeostasis. BBB dysfunction has been associated with multiple neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS); however, the role of the BBB in neurodegeneration is understudied. We developed an ALS patient-derived model of the BBB by using cells derived from 5 patient donors carrying C9ORF72 mutations. Brain microvascular endothelial-like cells (BMEC-like cells) derived from C9ORF72-ALS patients showed altered gene expression, compromised barrier integrity, and increased P-glycoprotein transporter activity. In addition, mitochondrial metabolic tests demonstrated that C9ORF72-ALS BMECs display a significant decrease in basal glycolysis accompanied by increased basal and ATP-linked respiration. Moreover, our study reveals that C9-ALS derived astrocytes can further affect BMECs function and affect the expression of the glucose transporter Glut-1. Finally, C9ORF72 patient-derived BMECs form leaky barriers through a cell-autonomous mechanism and have neurotoxic properties towards motor neurons

Crystallization Characteristics of CaO-Al2O3-Based Mold Flux and Their Effects on In-Mold Performance during High-Aluminum TRIP Steels Continuous Casting

Crystallization behaviors of the newly developed lime-alumina-based mold fluxes for high-aluminum transformation induced plasticity (TRIP) steels casting were experimentally studied, and compared with those of lime-silica-based mold fluxes. The effects of mold flux crystallization characteristics on heat transfer and lubrication performance in casting high-Al TRIP steels were also evaluated. The results show that the crystallization temperatures of lime-alumina-based mold fluxes are much lower than those of lime-silica-based mold fluxes. Increasing B2O3 addition suppresses the crystallization of lime-alumina-based mold fluxes, while Na2O exhibits an opposite effect. In continuous cooling of lime-alumina-based mold fluxes with high B2O3 contents and a CaO/Al2O3 ratio of 3.3, faceted cuspidine precipitates first, followed by needle-like CaO center dot B2O3 or 9CaO center dot 3B(2)O(3)center dot CaF2. In lime-alumina-based mold flux with low B2O3 content (5.4 mass pct) and a CaO/Al2O3 ratio of 1.2, the formation of fine CaF2 takes place first, followed by blocky interconnected CaO center dot 2Al(2)O(3) as the dominant crystalline phase, and rod-like 2CaO center dot B2O3 precipitates at lower temperature during continuous cooling of the mold flux. In B2O3-free mold flux, blocky interconnected 3CaO center dot Al2O3 precipitates after CaF2 and 3CaO center dot 2SiO(2) formation, and takes up almost the whole crystalline fraction. The casting trials show that the mold heat transfer rate significantly decreases near the meniscus during the continuous casting using lime-alumina-mold fluxes with higher crystallinity, which brings a great reduction of surface depressions on cast slabs. However, excessive crystallinity of mold flux causes poor lubrication between mold and solidifying steel shell, which induces various defects such as drag marks on cast slab. Among the studied mold fluxes, lime-alumina-based mold fluxes with higher B2O3 contents and a CaO/Al2O3 ratio of 3.3 show comparatively improved performance.ope

A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil