The Arabidopsis tandem-pore K super(+) (TPK) channels displaying four transmembrane domains and two pore regions share structural homologies with their animal counterparts of the KCNK family. In ...contrast to the Shaker-like Arabidopsis channels (six transmembrane domains/one pore region), the functional properties and the biological role of plant TPK channels have not been elucidated yet. Here, we show that AtTPK4 (KCO4) localizes to the plasma membrane and is predominantly expressed in pollen. AtTPK4 (KCO4) resembles the electrical properties of a voltage-independent K super(+) channel after expression in Xenopus oocytes and yeast. Hyperpolarizing as well as depolarizing membrane voltages elicited instantaneous K super(+) currents, which were blocked by extracellular calcium and cytoplasmic protons. Functional complementation assays using a K super(+) transport-deficient yeast confirmed the biophysical and pharmacological properties of the AtTPK4 channel. The features of AtTPK4 point toward a role in potassium homeostasis and membrane voltage control of the growing pollen tube. Thus, AtTPK4 represents a member of plant tandem-pore-K super(+) channels, resembling the characteristics of its animal counterparts as well as plant-specific features with respect to modulation of channel activity by acidosis and calcium.
The design, synthesis, and analysis of analogs of d(CGCGAATTCGCG)2 possessing one or two intrahelical disulfide cross-links is reported. The cross-linked oligomers were prepared by first synthesizing ...duplexes where the 3‘- and 5‘-terminal bases of the parent sequence were replaced with N 3 -thioethylthymidine. Following deprotection and purification, air oxidation afforded the desired cross-linked constructs in high yield. Analysis of both the oxidized (disulfide cross-linked) and reduced (thiol modified) duplexes by UV, circular dichroism, and NMR spectroscopies along with susceptibility to EcoRI cleavage indicates that the modifications are not structurally perturbing. Optical thermal denaturation and differential scanning calorimetry measurements suggest that introducing disulfide cross-link(s) into d(CGCGAATTCGCG)2 does, however, cause two fundamental changes. First, the cross-link(s) increase the thermal stability of the modified duplexes by changing the molecularity of denaturation without an increase in enthalpy. Second, the disulfide cross-link traps one of the conformations of the conformationally heterogeneous parent molecule resulting in a conformationally homogeneous system. Both of these features are themselves unique and will be important for further applications of disulfide cross-linked oligomers such as these in studies of nucleic acid structure and function.
The time for arterial PO2 to reach equilibrium after a 0.2 increase in the fraction of inspired oxygen (FIO2) was studied, using arterial blood gases measured at 1, 2, 3, 4, 5, 7, 9, and 11 min in 30 ...stable, mechanically ventilated medical intensive care unit (ICU) patients. Eight patients also underwent a 0.4 increase in FIO2. Each patient's rise in PO2 over time PO2(t) was fit to the following exponential equation: PO2(t) = PO2i + (PO2f-PO2i) (1-e-kt), where t refers to time, PO2i and PO2f refer to the initial and final equilibrated PO2. The time constant k and PO2f were determined by a nonlinear curve fitting technique. The 90% oxygenation times (t90%), defined as the time required to reach 90% of the final equilibrated PO2, were calculated. The mean t90% (+/- SD) was 6.0 (+/- 3.4) min for all patients (range 1.7 to 14.3 min); 7.1 +/- 2.1 min for 18 patients with chronic obstructive pulmonary disease (COPD) and 4.4 +/- 2.0 min for 12 patients without COPD (p < 0.05). In the subgroup of patients undergoing both an FIO2 increase of 0.2 and 0.4, there was no significant difference in the mean t90%'s for the two FIO2 changes (7.7 versus 7.7 min). We conclude that after a 0.2 or 0.4 increase of FIO3, a 15-min equilibration time period is adequate for 90% of the increase in PO2 to occur, in stable, mechanically ventilated medical ICU patients.
We propose a surface model that can be used as part of an internet based educational medical simulator to train physicians in cardiovascular interventions. This is the first step towards building a ...real device which can be placed in a remote laboratory and operated upon by physicians from the comfort of their homes. The model assembles arteries and has planar segmentation to increase efficiency of the collision-detection algorithm. It is based on Sweep Surfaces and can be extended to T- and Y-like bifurcations with small mesh deformations. We also describe a continuous force vector field, representing the interaction between the catheter and the surface. The computation time is almost unaffected when the resolution of the artery is increased, and the algorithm allows real-time executions which are very important for remote learning.
A new diagnostic approach is reported, which combines Doppler echocardiography and a thermodilution technique for the calculation of mitral valve area at rest and during exercise. This method was ...applied to determine the magnitude of mitral valve reserve (= exercise-induced increase of mitral valve are) and to assess the hemodynamic relevance of mitral stenosis.
69 patients with mitral stenosis were included in this study. A Swan-Ganz catheter was used to measure exercise hemodynamics and transvalvular flow by a thermodilution technique. The mean transmitral flow velocity vmean was determined by continuous wave Doppler. Measurements were performed simultaneously at rest and during stepwise bicycle ergometry. Effective mitral valve area was calculated according to the continuity equation method (MVACE = Flow/vmean).
A significant exercise-induced increase of mitral valve area was found in the total group (rest-->25 W: 1.1 +/- 0.3-->1.3 +/- 0.4 cm2, p < 0.001). Two subgroups were defined according to the presence or absence of mitral valve reserve: delta MVA > and = 20%: group A (n = 30); delta MVA < 20%: group B (n = 39). Both groups did not differ with regard to mitral valve area at rest. However, the increase of cardiac output and stroke volume was significantly higher in group A than in group B. An effective mitral valve area at 25 W of less than 1.2 cm2 had an 80% sensitivity and an 83% specificity to detect a severe mitral stenosis.
Because the presence and extent of mitral valve reserve cannot be predicted under resting conditions measurements under flow-increasing interventions are necessary. Our data demonstrate that exercise Doppler in conjunction with right-sided cardiac catheterization is most useful to determine mitral valve reserve and to assess the hemodynamic relevance of mitral stenosis.
Knock it off Der, Matthew F.; Saul, Lawrence K.; Savage, Stefan ...
Proceedings of the 20th ACM SIGKDD international conference on Knowledge discovery and data mining,
08/2014
Conference Proceeding
We describe an automated system for the large-scale monitoring of Web sites that serve as online storefronts for spam-advertised goods. Our system is developed from an extensive crawl of black-market ...Web sites that deal in illegal pharmaceuticals, replica luxury goods, and counterfeit software. The operational goal of the system is to identify the affiliate programs of online merchants behind these Web sites; the system itself is part of a larger effort to improve the tracking and targeting of these affiliate programs. There are two main challenges in this domain. The first is that appearances can be deceiving: Web pages that render very differently are often linked to the same affiliate program of merchants. The second is the difficulty of acquiring training data: the manual labeling of Web pages, though necessary to some degree, is a laborious and time-consuming process. Our approach in this paper is to extract features that reveal when Web pages linked to the same affiliate program share a similar underlying structure. Using these features, which are mined from a small initial seed of labeled data, we are able to profile the Web sites of forty-four distinct affiliate programs that account, collectively, for hundreds of millions of dollars in illicit e-commerce. Our work also highlights several broad challenges that arise in the large-scale, empirical study of malicious activity on the Web.
Autobiographical writings have been a major cultural genre from antiquity to the present time. General questions of the literary as, e.g., the relation between literature and reality, truth and ...fiction, the dependency of author, narrator, and figure, or issues of individual and cultural styles etc., can be studied preeminently in the autobiographical genre. Yet, the tradition of life-writing has, in the course of literary history, developed manifold types and forms. Especially in the globalized age, where the media and other technological / cultural factors contribute to a rapid transformation of lifestyles, autobiographical writing has maintained, even enhanced, its popularity and importance. By conceiving autobiography in a wide sense that includes memoirs, diaries, self-portraits and autofiction as well as media transformations of the genre, this three-volume handbook offers a comprehensive survey of theoretical approaches, systematic aspects, and historical developments in an international and interdisciplinary perspective. While autobiography is usually considered to be a European tradition, special emphasis is placed on the modes of self-representation in non-Western cultures and on inter- and transcultural perspectives of the genre. The individual contributions are closely interconnected by a system of cross-references. The handbook addresses scholars of cultural and literary studies, students as well as non-academic readers.
Pulmonary surfactant is composed mainly of phospholipid and two groups of apoproteins. One of these apoproteins is a family of glycoproteins (pulmonary surfactant-associated protein A, PSP-A). We ...have isolated and sequenced a cDNA clone encoding for rat PSP-A and the full amino acid sequence has been deduced from the nucleotide sequence. The sequence of 56 amino acids at the N-terminus of PSP-A isolated from rats treated with silica was determined independently, and there is complete agreement with the sequence deduced from the cDNA. Isolated rat alveolar type II cells contain two species of mRNA for this protein.
Abstract
Hybridomas expressing murine γδ T‐cell receptors were found to produce cytokines in response to cardiolipin (CL) and structurally related anionic phospholipids. This response required serum ...at concentrations related to the amount of CL in cultures. The purified serum factor, β
2
‐glycoprotein 1 (β
2
‐GP1) (apolipoprotein H), supported the CL response alone, whereas several other serum proteins and ovalbumin did not. β
2
‐GP1 is known to form complexes with anionic phospholipids, particularly CL, which are often recognized by pathological autoantibodies. We speculate that γδ T cells also recognize such complexes and that the hybridoma response reported here reflects this specificity.
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