Direct and collateral effects of restraints and restraint fading

Mechanical restraints are commonly used to reduce the risks associated with severe self-injurious behavior (SIB), but may result in movement restriction and adverse side effects (e.g., bone demineralization). Restraint fading may provide a method for decreasing SIB while increasing movement and reducing these side effects. In the current investigation, rigid arm sleeves and restraint fading (gradually reducing the rigidity of the sleeves) were used with 3 clients who engaged in hand-to-head SIB. Restraints and fading reduced the hand-to-head SIB of all clients. However, for 1 client, the addition of a water mist procedure further reduced SIB to near-zero levels. For a 2nd client, another form of SIB developed that was not prevented by the rigid sleeves. For a 3rd client, a topography of SIB that was not physically prevented by the rigid sleeves was also reduced when restraints and fading were introduced.     

Characterization of ionotropic glutamate receptor-mediated nitric oxide production in vivo in rats

BACKGROUND AND PURPOSE: Glutamate receptor activation can stimulate nitric oxide (NO) production and possibly play a role in long-term potentiation and excitotoxic-mediated injury. We studied the differential effect of agonist-induced activation of ion channel-linked N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor subtypes on NO production in vivo in rat hippocampus. We also studied whether dantrolene, a ryanodine calcium channel inhibitor previously shown to attenuate metabotropic glutamate receptor stimulation of NO production, also attenuated ionotropic glutamate receptor-mediated stimulation of NO production. METHODS: Microdialysis probes were placed bilaterally into the CA3 region of the hippocampus of pentobarbital-anesthetized adult Sprague-Dawley rats and were perfused for 5 hours with artificial cerebrospinal fluid (CSF) containing 3 mumol/L [14C]L-arginine. Recovery of [14C]L-citrulline in the effluent was used as a marker of NO production. In 13 groups of rats, increases in [14C]L-citrulline recovery were compared between right- and left-sided probes perfused with no additional drugs versus combinations of NMDA, AMPA, the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME), the non-competitive glutamate receptor blocker MK-801, the AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and dantrolene. RESULTS: Recovery of [14C]L-citrulline during perfusion with artificial CSF progressively increased to 272 +/- 73 fmol/min (+/-SEM) over 5 hours. Contralateral perfusion with 1 mmol/L L-NAME inhibited [14C]L-citrulline recovery. Perfusion with 1 mmol/L MK-801 or 1 mmol/L CNQX reduced [14C]L-citrulline recovery compared with contralateral perfusion with CSF alone. Perfusion with 1 mmol/L NMDA enhanced [14C]L-citrulline recovery, and this enhancement was attenuated by L-NAME, MK-801, and CNQX but not by dantrolene. Perfusion with 1 mmol/L AMPA enhanced [14C]L-citrulline recovery, and this enhancement was also attenuated by L-NAME, MK-801, and CNQX but not by dantrolene. CONCLUSIONS: Through an indirect method of assessing NO production in vivo, results with MK-801 and CNQX indicate that NMDA and AMPA receptor activation contribute to basal NO production in the rat hippocampus. Enhanced NO production with NMDA and AMPA agonists appears to involve a complex neuronal interaction because the effect of NMDA was attenuated by both MK-801 and CNQX and because the effect of AMPA was attenuated by both CNQX and MK-801. In contrast to metabotropic glutamate receptor activation, release of calcium from intracellular ryanodine calcium channels does not appear to be a prominent mediator of ionotropic glutamate receptor stimulation of NO production.     

Extracardiac conduit Fontan procedure without cardiopulmonary bypass

There are a number of potential advantages of extracardiac conduit cavopulmonary anastomosis for palliation of functional single ventricle heart disease, including the ability to perform the operation with no aortic cross-clamping and with minimal duration of extracorporeal circulation. In many patients, it may be possible to perform the procedure without cardiopulmonary bypass altogether. In this report, we present our technique for performing the extracardiac conduit Fontan operation without cardiopulmonary bypass.     

The Effect of Conditioning on Adhesion to Human Dentin

The effect of conditioning dentin was investigated using ethyleneglycol bis(aminoethylether) tetraacetic acid (EGTA) and three proprietary agents containing ethylenediamine tetraacetic acid (EDTA), maleic acid and dipentaerythritol pentaacrylate phsophoric acid ester (PENTA). Ground dentin was treated with EGTA or one of the three proprietary agents. After adhering composite resin to treated surfaces, the shear bond strength (SBS) was determined with and without thermal stress. Scanning electron and atomic force microscopies were used to assess morphological effects of each of the agents, while low resolution X-ray photoelectron spectroscopy (XPS) was employed to evaluate elemental changes due to treatment. Mean bond strength was greatest for the PENTA-conditioned surfaces. EDTA and maleic acid demineralized the dentin surface while the agent containing PENTA produced an adherent surface film. The XPS survey showed a reduction in Ca and an increase in N for agents containing EGTA, EDTA and maleic acid, while a simultaneous reduction in both these species was observed for PENTA. EGTA did not improve adhesion for systems which were based on smear layer removal and substrate demineralization. For the PENTA-based system, which relied on the development of a molecular overlayer, EGTA degraded bond strength.     

Simulation and SANS Studies of gelation under shear

Computer simulations of a two-dimensional Lennard-Jones fluid undergoing spinodal decomposition are reported for the system subjected to planar Couetic flow. Key results are the images of the atomic structure and plots of the corresponding pair correlation functions. A companion small-angle neutron scattering (SANS) study of shear-innuenced gelation in colloidal silica suspensions at volume fractions =0. l, (1.13, 0.18, and 0.24 is discussed. It is found that the scattered intensity wave vector curves from the unsheared gels obey a power law lor < 0.34. At higher volume fractions, the power law does not seem to be followed. Shear. however. induces an apparent fractal structure in the gel at = 0.24 Results from the computer and the SANS experiments indicate that the spinodal decomposition process and the getalion mechanism have features in common.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Fundamentals of Materials Selection for Light‐Emitting Electrochemical Cells

The in situ formation of a light‐emitting p–n or p–i–n junction in light‐emitting electrochemical cells (LECs) necessitates mixed ionic–electronic conductors in the active layer. This unique characteristic requires electronic, luminescent, and ionic ingredients that work synergistically in the LECs. The material requirements that lead to promising electroluminescent properties are discussed and the important components reported so far are surveyed. Particular attention is paid to the working mechanisms behind junction formation and stabilization to create efficient and stable electroluminescence in conjugated‐polymer‐based LECs. Keeping these fundamentals in mind explains how LEC devices have evolved from classic conjugated polymer blends into highly stable crosslinked, hybrid composite, and stretchable device architectures. To conclude, a future development strategy is proposed based on a dual approach: develop new materials specifically for LEC devices and explore novel ways to efficiently process and stabilize the p–i–n junction, which will drive improvements in both LEC external quantum efficiency and operating lifetime toward truly low‐cost solid‐state lighting applications.