Structural features of thyroid hormone response elements that increase susceptibility to inhibition by an RTH mutant thyroid hormone receptor

The chicken lysozyme silencer F2 (F2) thyroid hormone response element (TRE) contains an unusual everted palindromic arrangement, has a high affinity for thyroid hormone receptor (TR) homodimers, and is especially sensitive to dominant negative inhibition by, the T3 resistance (RTH) mutant TR beta P453H. We used various TREs and TR mutations to determine the mechanisms for this sensitivity. Changing the F2 orientation from an everted palindrome to a direct repeat with a 4-bp gap (DR+4) (F2-DR) decreased the sensitivity to inhibition at high T3 concentrations, while a loss of this sensitivity occurred with a palindromic arrangement of these same half-sites. F2 contains the dinucleotide TG 5' to each consensus half-site conforming to the optimal TR-binding octamer, YRRGGTCA. A T to A change in position 1 of both F2 half-sites markedly reduced T3-induction, yet only slightly reduced TR homodimer or TR-retinoid X receptor (RXR) heterodimer binding. The TR beta ninth heptad mutation, L428R, prevents TR heterodimerization with RXR and eliminates the inhibitory effect of the P453H mutant TR on the F2-DR, but not the F2 element. Structural features of a TRE that favor strong TR binding of both TR homodimers and TR-RXR heterodimers containing the mutant TR, such as the everted palindromic conformation or the optimal TR-binding consensus octamer, enhance the sensitivity of a TRE to inhibition by the mutant TR. Thus, both half-site orientation and sequence contribute to the sensitivity of a given TRE to dominant negative inhibition by a mutant TR.     

Katalytischer wasserstoff-/sauerstoff-rekombinator mit selbstbegrenzung

Lead-acid cells evolve hydrogen and oxygen gasses during the charging mode, which results in a water loss. Gas recombination devices extend the water refilling periods due to the recombination reactionH₂ + $\text{1}\text{2}$O₂ → H₂O The recombination devices consist of: aerosol retainer, charcoal filter, catalyst, condenser, gas storage and vents. Theoretical models describing the self-limiting behaviour of the catalyst and the heat flow conditions in the device were developed.Design specifications of component requirements for a 435-W recombination device, which is capable of recombining 182 l/h stoichiometric oxyhydrogen gas, were also developed. Tests with the system (recombination device-lead-acid cell) showed that a maintenance-free and nearly gastight operation was achieved. The use of catalytic recombination devices improves the economy and safety of battery operation.     

Readmission discount factors in program evaluation. An output value analysis of an adult psychiatry program

The application of output value analysis, a type of benefit/cost analysis, to a psychiatric patient population is reported. A method for discounting the value of the program if a patient was readmitted within a year after discharge was introduced. The application of this discount factor reduces the value produced by the program and thereby reduces both productivity and effectiveness indices. When applied to groups known to differ in readmission rates, such as first admissions and readmissions or voluntary and involuntary admissions, the discount factor can accentuate group differences markedly. When selected diagnostic groups were compared, the discount factor could even reverse the relative standing of the groups.     

Cytogenetic studies of the Australian rodent, Uromys caudimaculatus, a species showing extensive heterochromatin variation

The Australian rodent, Uromys caudimaculatus, consists of two chromosome races. a) The Southern Race is characterized by the possession of two to twelve B-chromosomes. These vary considerably in size, morphology, and C- and G-banding characteristics, they behave as univalent at meiosis and are inherited in a random manner. b) The Northern Race lacks B-chromosomes, but possesses large blocks of distal C-positive heterochromatin on between 18 and 28 of the 46 chromosomes. The C-blocks may be entirely G-positive entirely G-negative, or G-banded, suggesting heterogeneity with the C-blocks. There is extensive variation both between and within populations of the northern race in the number and size of the distal heterochromatic blocks. There is no apparent difference between the races in chiasma frequency. The northern race does have much higher proportion of interstitial versus distal chiasmata, although it is probable that this is merely a reflection of lack of crossing over in the heterochromatic blocks rather than an actual shift of chiasma localisation within the euchromatin. Despite the extensive differences between the races in the amount and organization of constitutive heterochromatin, hybrids show no abnormalities at meiosis and they are fully fertile.     

Enabling Distributed Medium Access Control for Impulse-Based Ultrawideband Radios

Impulse-based ultrawideband (I-UWB) is an attractive radio technology for large ad hoc and sensor networks due to its robustness to multipath effects, subcentimeter ranging ability, simple hardware, and low radiated power. Large distributed networks, such as ad hoc and sensor networks, often implement distributed medium access control (MAC) protocols based on carrier sense multiple access (CSMA). In CSMA, narrowband systems check for medium activity before transmitting by checking for in-band energy around a carrier frequency. I-UWB systems lack a carrier, and the narrow pulses, low radiated power, harsh channel conditions, and strict Federal Communications Commission power limits present challenges in detecting medium activity. We propose a pulse sensor for I-UWB systems that overcomes the challenges of quickly, reliably, and efficiently identifying medium activity. The pulse sensor enables distributed MAC protocols for I-UWB radios that are analogous to CSMA for narrowband radios. Simulations show that the proposed pulse sensor architecture is practical for I-UWB radios     

Proteomics of brain synapses and molecular dissection of synaptic subdomains

Synapses form the nuts and bolts of the brain. Synaptic transmission involves an intricate network of synaptic proteins that forms the molecular machinery underlying transmitter release, activation of transmitter receptors, and signal transduction cascades. It is generally believed that neuronal activity-dependent change of synaptic efficacy is at the basis of learning and memory and is encoded by sequential molecular events at the synapse. In the past 2-3?years, a number of proteomics studies have been performed on synaptic subdomains, including synaptic vesicles, postsynaptic density, synaptic lipid raft, synapse protein complexes, as well as on synaptic protein PTMs, notably phosphorylation. The activity-dependent dynamics of protein constituents of the synapse are starting to be examined by quantitative proteomics. It is anticipated that these analyses will yield novel insights into the organization of the synapse, and will generate testable hypotheses of synapse function and regulation both in health and disease.