Search results for "response"

Age-dependent differences in the effect of phenprocoumon on the vitamin K1-epoxide cycle in rats

1980

Abstract The anticoagulant activity and the pharmacokinetics of phenprocoumon as well as the effect of phenprocoumon on the vitamin K1-epoxide cycle in younger (12 weeks) and older (36 weeks) male inbred Lewis rats has been examined in a study of the mechanism responsible for the increase in the responsiveness to oral anticoagulant drugs (OAD's) with increasing age. After a single i.v.-dose of phenprocoumon (0†355 mg kg−1 the anticoagulant effect obtained was greater in older than in younger rats. There were no differences between younger and older rats in the rate of elimination, volume of distribution and in the free fraction and free concentration values of phenprocoumon in plasma and li…

Test fairness: a DIF analysis of an L2 vocabulary test

2000

The purpose of this study is to analyse gender-uniform differential item functioning (DIF) in a second language (L2) vocabulary test with the tools of item response theory (the separate calibration t-method) and to study potential gender impact on the test performance measured by different item composites. The results of the study show that despite the fact that there are test items with indications of DIF in favour of either females or males, the test as a whole is not gender-biased. In spite of this, it was demonstrated that some item composites are gender-biased. In view of item bank building and use, it means that some of the tests constructed on the basis of an item bank might be bias…

Modulation of voltage-gated Na+ and K+ channels by pumiliotoxin 251D: A “joint venture” alkaloid from arthropods and amphibians

2008

Abstract Certain amphibians provide themselves with a chemical defense by accumulating lipophilic alkaloids into skin glands from dietary arthropods. Examples of such alkaloids are pumiliotoxins (PTXs). In general, PTXs are known as positive modulators of voltage-gated sodium channels (VGSCs). Unlike other PTXs, PTX 251D does not share this characteristic. However, mice and insect studies showed that PTX 251D is highly toxic and to date the basis of its toxicity remains unknown. In this work, we searched for the possible target of PTX 251D . The toxin was therefore made synthetically and tested on four VGSCs (mammalian rNa v 1.2/β 1 , rNa v 1.4/β 1 , hNa v 1.5/β 1 and insect Para/tipE ) and…

Electromechanical coupling in anodic niobium oxide: Electric field-induced strain, internal stress, and dielectric response

2012

Seemingly, contradictory results have been reported so far for electrostriction in anodic oxides. Furthermore, no definitive agreement could be obtained with theory. In this paper, in situ techniques are combined to elucidate electrostriction in anodic niobium oxide. The dependence of strain, internal stress, and dielectric constant on the electric field is measured by, respectively, spectroscopic ellipsometry, curvature, and impedance measurements. The through-thickness strain is tensile and proportional to the square of the electric field. The in-plane internal stress is compressive and proportional to the square of the electric field at low field values. The internal stress is predicted …

Parasite-induced change in host behaviour and susceptibility to predation in an eye fluke–fish interaction

2004

Abstract Trophically transmitted parasites may increase their transmission efficiency by altering the behaviour of infected hosts to increase their susceptibility to predation by target hosts (the next host in the life cycle). The parasite Diplostomum spathaceum (Trematoda) reduces the vision of its fish intermediate hosts: its metacercariae lodge themselves in the eyes of fish and induce cataract formation, which gives them the opportunity to affect fish behaviour. We examined whether D. spathaceum eye flukes change the preference of fish for the surface layers of the water column or their escape behaviour, which could make the fish more vulnerable to predation by bird hosts. We also studi…

Combination of finite impulse response neural network technique with FDTD method for simulation of electromagnetic problems

1996

The finite difference time domain (FDTD) method requires long computation times for simulating resonant or high-Q structures. The authors incorporate the finite impulse response neural network technique as a predictor in order to save time in FDTD simulations. The applicability of the technique is demonstrated by carrying out an analysis of a waveguide filter.

FDTD signal extrapolation using a finite impulse response neural network model

1999

Web Server Support for e-Customer Loyalty through QoS Differentiation

2013

The paper deals with the problem of offering predictive service in e-commerce Web server systems under overload. Due to unpredictability of Web accesses, such systems often fail to effectively handle peak traffic, which results in long delays and incomplete transactions. As a consequence, online retailers miss an opportunity to attract new customers, retain the loyalty of regular customers, and increase profits. We propose a method for priority-based admission control and scheduling of requests at the Web server system in order to differentiate Quality of Service (QoS) with regard to user-perceived delays, i.e., Web page response times provided by the system (as opposed to HTTP request resp…

Effect of Ligands on HP-Induced Unfolding and Oligomerization of β-Lactoglobulin

2020

ABSTRACTTo probe intermediate states during unfolding and oligomerization of proteins remains a major challenge. High pressure (HP) is a powerful tool for studying these problems, revealing subtle structural changes in proteins not accessible by other means of denaturation. Bovine β-lactoglobulin (BLG), the main whey protein, has a strong propensity to bind various bioactive molecules, such as retinol and resveratrol, two ligands with different affinity and binding sites. By combining in situ HP-small-angle neutron scattering (SANS) and HP-UV/visible absorption spectroscopy, we report the specific effects of these ligands on 3D conformational and local changes in BLG induced by HP. Dependin…

Booster vaccination after neonatal priming with acellular pertussis vaccine.

2010

After a birth dose of acellular pertussis (aP) and diphtheria (DT)aP-hepatitis B virus (HBV)-inactivated polio vaccine (IPV)/ Haemophilus influenza type b (Hib) at 2, 4, and 6 months, a booster dose of DTaP-HBV-IPV/Hib at 12 to 23 months induced strong anti-pertussis booster responses. Thus, neonatal aP priming did not lead to immune tolerance to pertussis antigens. However, it elicited bystander interference on HBV, Hib, and diphtheria responses.