A second pathway of activation of the Torpedo acetylcholine receptor channel

We have studied the interaction of the reversible acetylcholine esterase inhibitor (-)physostigmine (D-eserine) with the nicotinic acetylcholine receptor (nAChR) from Torpedo marmorata electric tissue by means of ligandinduced ion flux into nAChR-rich membrane vesicles and of equilibrium binding. We find that (—)physostigmine induces cation flux (and also binds to the receptor) even in the presence of saturating concentrations of antagonists of acetylcholine, such as D-tubocurarine, a-bungarotoxin or antibody WF6, The direct action on the acetylcholine receptor is not affected by removal of the methylcarbamate function from the drug and thus is not due to carbamylation of the receptor. Antibodies FKl and benzoquinonium antagonize channel activation (and binding) of eserine, suggesting that the eserine binding site(s) is separate from, but adjacent to, the acetylcholine binding site at the receptor. In addition to the channel activating site(s) with an affinity of binding in the 50 nM range, there exists a further class of low-affinity (K^ ~ mM) sites from which eserine acts as a direct blocker of the acetylcholine-activatcd channel. Our results suggest the existence of a second pathway of activation of the nAChR channel

Desensitization is a property of the cholinergic binding region of the nicotinic acetylcholine receptor, not of the receptor-integral ion channel

The reversible acctylchollne esternse inhibitor (-}.physostiilmine (¢serine) is th© prolotypc of a new class of nie~tinlc ucetylcholinc receptor (nAChR) activating liga,ds: it induces cation fluxes into nAChR.rich membrane vesicl~s from 7~r#eda marmoeata cle~:tric tissue even under condl. lions of antalionist blocked :tcctylcholin~ binding sil~s (Okonjo, Kuhlm~mn. Maelicke. Neuron, in press). This su~tlest's that escrine exerts it~ than. nel.activating proi'~rty via binding sites at the nAChR separate from those of tile natural transmitter. We now report thllt eserine e'-m activate the channel wen when the receptor has t~en preincub~ttcd (des©nsitiz©d) with elevated concentrations of acetylcholi~e, Titus the confornudional state Of the receptor corresponding to de~nsitixation is confined to the transmitter bindinB rclli0n, leaving the ch=tr'4nel fully activatable ,- albeit only from other than the tr~msmitter bindin~ site(s)

Prediction of service life of polymeric sealant compositions for fuel tanks in aerospace structures from measurements of viscoelastic properties Annual report

Prediction of service life of polymeric sealers for fuel tanks from viscoelastic measurement

ELITE OUTSIDE HITTERS IN VOLLEYBALL DO NOT MEET THEIR INDIVIDUAL POSSIBLE MAXIMUM IMPACT HEIGHT IN HIGH SPIKE JUMPS

It is assumed that a high impact height is a relevant factor for success in volleyball spikes. The purpose of the study was to investigate whether outside hitters hit the ball at the highest possible impact height. Spikes from position IV were analysed at a tournament of the European League. The posture of the athletes was less extended in the trunk and upper limb with increasing jump height. Regarding the body posture at the moment of impact, there was no effect on the post impact ball speed. It is concluded that there could be enhancement with respect to the impact height as jump height increases even in elite athletes without reducing ball speed. This should be addressed within the training process

Multilevel correlates of household anthropometric typologies in Colombian mothers and their infants

Background. The aim of this study was to establish the association of maternal, family, and contextual correlates of anthropometric typologies at the household level in Colombia using 2005 Demographic Health Survey (DHS/ENDS) data.Methods. Household-level information from mothers 18-49 years old and their children less than 5 years old was included. Stunting and overweight were assessed for each child. Mothers were classified according to their body mass index. Four anthropometric typologies at the household level were constructed: normal, underweight, overweight, and dual burden. Four three-level [households (n = 8598) nested within municipalities (n = 226), nested within states (n = 32)] hierarchical polytomous logistic models were developed. Household log-odds of belonging to one of the four anthropometric categories, holding 'normal' as the reference group, were obtained.Results. This study found that anthropometric typologies were associated with maternal and family characteristics of maternal age, parity, maternal education, and wealth index. Higher municipal living conditions index was associated with a lower likelihood of underweight typology and a higher likelihood of overweight typology. Higher population density was associated with a lower likelihood of overweight typology.Conclusion. Distal and proximal determinants of the various anthropometric typologies at the household level should be taken into account when framing policies and designing interventions to reduce malnutrition in Colombia. Copyright © The Author(s) 2018

Maternal and familial correlates of anthropometric typologies in the nutrition transition of Colombia, 2000–2010

Q2Q1Objective: We aimed to assess the maternal and family determinants of four anthropometric typologies at the household level in Colombia for the years 2000, 2005 and 2010. Design: We classified children <5 years old according to height-for-age Z-score (2) to assess stunting and overweight/obesity, respectively; mothers were categorized according to BMI to assess underweight (<18·5 kg/m2 ) and overweight/obesity (≥25·0 kg/m2 ). At the household level, we established four final anthropometric typologies: normal, underweight, overweight and dual-burden households. Separate polytomous logistic regression models for each of the surveyed years were developed to examine several maternal and familial determinants of the different anthropometric typologies. Setting: National and sub-regional (urban and rural) representative samples from Colombia, South America. Subjects: Drawing on data from three waves of Colombia’s Demographic and Health Survey/Encuesta Nacional de Salud (DHS/ENDS), we examined individual and household information from mothers (18–49 years) and their children (birth– 5 years). Results: Higher parity was associated with an increased likelihood of overweight and dual burden. Higher levels of maternal education were correlated with lower prevalence of overweight, underweight and dual burden of malnutrition in all data collection waves. In 2010, participation in nutrition programmes for children <5 years, being an indigenous household, food purchase decisions by the mother and food security classification were also associated with the four anthropometric typologies. Conclusions: Results suggest that maternal and family correlates of certain anthropometric typologies at the household level may be used to better frame policies aimed at improving social conditions and nutrition outcomes.Revista Internacional - Indexad

Sequential Rotation of Antenna Array Elements – Rotation Angle for Optimum Array Polarization

The principle of sequential rotation, a well-known method to arrange the radiating elements of antenna arrays, is briefly described, and the impact on the polarization of different antenna array configurations is presented. The influence of the number of rotations and rotation angles is investigated, and arrangements for optimized polarization quality of antenna arrays are shown, which are of significant importance for current and future communications systems.</p

Muscle satellite cell proliferation and association: new insights from myofiber time-lapse imaging

<p>Abstract</p> <p>Background</p> <p>As the resident stem cells of skeletal muscle, satellite cells are activated by extracellular cues associated with local damage. Once activated, satellite cells will re-enter the cell cycle to proliferate and supply a population of myoblasts, which will repair or replace damaged myofibers by differentiating and fusing either with an existing myofiber or with each other. There is also evidence that the orientation of cell division with respect to the myofiber may indicate or convey asymmetry in the two daughter cells. Our recent studies with time-lapse imaging of myofiber-associated satellite cells <it>in vitro </it>have yielded new data on the timing and orientation of satellite cell divisions, and revealed persistent differences in the behavior of daughter cells from planar versus vertical divisions.</p> <p>Results</p> <p>We analyzed 244 individual fiber-associated satellite cells in time-lapse video from 24 to 48 hours after myofiber harvest. We found that initial cell division in fiber culture is not synchronous, although presumably all cells were activated by the initial trauma of harvest; that cell cycling time is significantly shorter than previously thought (as short as 4.8 hours, averaging 10 hours between the first and second divisions and eight hours between the second and third); and that timing of subsequent divisions is not strongly correlated with timing of the initial division. Approximately 65% of first and 80% of second cell divisions occur parallel to the axis of the myofiber, whereas the remainder occur outside the plane of the fiber surface (vertical division). We previously demonstrated that daughter cells frequently remain associated with each other after division or reassociate after a brief separation, and that unrelated cells may also associate for significant periods of time. We show in this paper that daughter cells resulting from a vertical division remain associated with one another several times longer than do daughters from a horizontal division. However, the total average time of association between sister cells is not significantly different from the total average time of association between unrelated cells.</p> <p>Conclusions</p> <p>These longitudinal characterizations of satellite cell behavior shortly after activation provide new insights into cell proliferation and association as a function of relatedness, and indicate significant and consistent heterogeneity within the population based on these metrics.</p