Cyclic GMP inhibits and shifts the activation curve of the delayed-rectifier (I[K1]) of type I mammalian vestibular hair cells

NITRIC oxide (NO) plays a role in the modulation of the predominant potassium current of type I vestibular hair cells, a low-voltage activated current called I(K1). Since many effects of NO are mediated via cGMP, patch-clamp recordings were made to evaluate the effects of cGMP on I(K1). In whole-cell recordings 1 mM cGMP shifted Vhalf of I(K1) by 15.0 +/- 2.4 mV (n = 6) to more positive. In cell-attached 'multichannel' recordings 1 mM 8-bromo-cGMP caused a reversible shift of Vhalf by 13.8 +/- 2.6 mV (n = 12) and in single channel recordings in the cell-attached configuration the open probability was reduced at -60 mV from 0.39 +/- 0.14 to 0.08 +/- 0.01. cGMP had no effect on excised inside-out patches, indicating that an intact cytosolic milieu with functioning phosphorylation cascades is necessary. cGMP seems to be an important second messenger which reduces the potassium conductance of vestibular hair cells.     

Efficient tracking of moving objects using a relational database

Tracking uncooperative moving objects by means of radar is a complex task due to clutter and association problems in multi-target scenarios. An approach to solve this problem is probabilistic multiple hypothesis tracking (PMHT). This method combines classical track filtering with a likelihood ratio test for the estimation of the plot-to-track association. The basics of PMHT and similar algorithms have gained much attention recently. However, the efficient implementation of real world applications of this technique still represents a challenging task. Since a common requirement in this context is the reliable storage of track data in a database, an implementation of the tracker's calculation inside a database management system (DBMS) using SQL views is desirable. A naive implementation of PMHT using a commercial DBMS, however, usually leads to performance problems because of the high frequency of measurement updates. In this paper, we propose possible optimizations for solving these performance problems. Their usage leads to a dramatic run-time improvement in our sample case and makes the implementation of PMHT in a database context feasible.     

Beyond fast mapping: Young children's extensions of novel words and novel facts.

L. Markson and P. Bloom (1997) concluded that there was evidence against a dedicated system for word learning on the basis of their finding that children remembered a novel word and a novel fact equally well. However, a word-learning system involves more than recognition memory; it must also provide a means to guide the extension of words to additional exemplars, and words and facts may differ with regard to extendibility. Two studies are reported in which 2–4-year-old children learned novel words and novel facts for unfamiliar objects and then were asked to extend the words and facts to additional exemplars of the training objects. In both studies, children extended the novel word to significantly more category members than they extended the novel fact. The results show that by 2 years of age, children honor the necessary extendibility of novel count nouns but are uncertain about the extendibility of arbitrary facts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrode microchamber for noninvasive perturbation of mammalian cells with nanosecond pulsed electric fields

Nanosecond pulsed electric fields can pass through the external membrane of biological cells and disturb fast-responding intracellular structures and processes. To enable real-time imaging and investigation of these phenomena, a microchamber with integral electrodes and optical path for observing individual cells exposed to ultrashort electric pulses was designed and fabricated utilizing photolithographic and microelectronic methods. SU-8 photoresist was patterned to form straight sidewalls from 10 to 30 /spl mu/m in height, with gold film deposited on the top and sidewalls for conductive, nonreactive electrodes and a uniform electric field. Channel dimensions (10-30 /spl mu/m/spl times/100 /spl mu/m/spl times/12000 /spl mu/m) are suitable for observations of mammalian cells during nanosecond, megavolt-per-meter pulsed electric field exposure. Experimental studies utilizing the electrode microchamber include live-cell imaging of nanoelectropulse-induced intracellular calcium bursts and membrane phospholipid translocation.     

Wear Performance of Dental Materials: A Comparison of Substructure Ceramics,Veneering Ceramics,and Non‐Precious Alloys

The aim of this in vitro study was to compare the two‐body wear resistance of different dental ceramics and non‐precious alloys. Two‐body wear tests were performed in a chewing simulator with steatite antagonists. A pin‐on‐block design with a vertical load of 50 N for 1.2 × 10⁵ cycles (f = 1.6 Hz; lateral movement: 1 mm, mouth opening: 2 mm) was used for the wear test. Surface roughness R_a (SP6, Perthen‐Feinprüf, G) and wear depth were determined using a 3D‐Profilometer (Laserscan 3D, Willytec, G). Scanning electron microscopy (Quanta FEG 400, FEI, NL) was applied for evaluating wear performance of both, materials and antagonists. Statistics: one‐way ANOVA (α = 0.05). The in vitro wear test showed that the wear performance of dental materials is strongly influenced by the type of material (ceramic, zirconia, or alloy). Zirconia and alloy provided low wear in contrast to glass‐ceramic systems. In contradiction to common expectations, hard zirconia and alloy systems showed even lower antagonistic wear than glass‐ceramics.     

Enhancement of secretagogue-induced adrenocorticotropic hormone release from cultured sheep anterior pituitary cells by recombinant ovine interleukin 1

Interaction between protein disulfide isomerase, possessing not only isomerase but also chaperone-like activity, and olygomeric enzyme, GAPDH, has been studied using technique of immobilization on insoluble support. PDI dimers bound to CNBr-activated Sepharose were shown to possess high TPOR activity as well as the ability to reactivate lysozyme. Immobilized PDI was not found to interact neither with soluble tetrameric GAPDH, nor with soluble denatured GAPDH. However, soluble PDI binds effectively to immobilized GAPDH monomers; Kd was found to be 3.7 x 10(-6) M, stoichiometry 0.824 mole PDI monomers per mole GAPDH monomers. Immobilized GAPDH tetramers do not interact with PDI. These observations are also confirmed by the data on electrophoresis of proteins bound to immobilized GAPDH monomers and tetramers. The ability of PDI to interact with denatured protein form, but not with the native one, is considered to be evidence of chaperone-like activity of the enzyme.