Manipulation of Arousal by Caffeine Reduces Metacontrast Masking Mostly When Target and Mask Shapes Are Incongruent

2013 ◽  
Vol 72 (2) ◽  
pp. 111-116 ◽  
Author(s):  
Norman Ojasoo ◽  
Carolina Murd ◽  
Mari Aru ◽  
Talis Bachmann
Keyword(s):  
Placebo Treatment ◽  
Arousal Level ◽  
Temporal Delay ◽  
Popular Method ◽  
General Arousal ◽  
Metacontrast Masking ◽  
Control Target ◽  
Sensory Interactions ◽  
Nonspecific Factors

Metacontrast masking is a popular method used to control target accessibility for explicit perception. It is thus a valuable tool in research on preconscious processing, consciousness mechanisms, and visual sensory interactions. However, the dependence of metacontrast effects on nonspecific factors determining subjects’ general arousal level has not been studied. We manipulated arousal by caffeine versus placebo treatment and found, instead of the expected uniform improvement in target perception with caffeine, an intricate interaction between target-to-mask temporal delay, congruence between target and mask shapes, and arousal condition. Caffeine improved target perception mostly when a longer SOA was used in combination with shape-wise incongruent target-mask pairings. Possible reasons for this effect are discussed.

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

Does Increased Platelet Release Normalize During Anti-Hypertensive Treatment?

1987 ◽  
Vol 58 (03) ◽  
pp. 834-838
Author(s):  
Knut Lande ◽  
Sverre Erik Kjeldsen ◽  
Ivar Eide ◽  
Paul Leren ◽  
Knut Gjesdal
Keyword(s):  
Platelet Function ◽  
Adrenergic Receptor ◽  
Blood Platelet ◽  
Placebo Treatment ◽  
Sampling Procedure ◽  
Β Blocker ◽  
Platelet Release ◽  
Hypertensive Drug ◽  
Second Period ◽  
Release Product

SummaryBlood platelet function was evaluated in 10 men, all 50 years old, with untreated, mild hypertension. Each patient was examined four times: At the beginning of the study, after 5 weeks on placebo treatment, after the following 5 weeks on propranolol 160 mg daily, and finally after a second period of 5 weeks on placebo. At baseline the plasma level of the platelet release product (β-thromboglobulin (BTG) was 41.6 (30.5-57.0) μg/l (median and 95% confidence interval). During the first placebo period BTG was normalized to 21.0 (14.1-25.9) μg/l. While systolic blood pressure and heart rate fell during β-adrenergic receptor blockade, BTG remained unchanged throughout the rest of the observation periods. Platelet size increased significantly during treatment with β-blocker. The present study indicates that the normalization of elevated platelet function which previously has been reported to occur during anti-hypertensive drug therapy, may be explained by patient adaptation to the blood sampling procedure.

Influence of Vitamin E on Plasma Malondialdehyde- Like Material in Man

1984 ◽  
Vol 51 (03) ◽  
pp. 347-348 ◽  
Author(s):  
C Cordova ◽  
A Musca ◽  
F Violi ◽  
C Alessandri ◽  
A Ghiselli ◽  
...  
Keyword(s):  
Vitamin E ◽  
Healthy Subjects ◽  
Placebo Treatment ◽  
Blind Study ◽  
Single Blind ◽  
Plasma Malondialdehyde

SummaryThe behaviour of plasma malondialdehyde-like material (MDA-LM) was evaluated in 13 healthy subjects by a single-blind study that consisted of placebo (30 days), vitamin E treatment (300 mg/day) (30 days) and placebo (30 days). The study demonstrated that MDA-LM did not change during placebo treatment while it significantly decreased after vitamin E administration.

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