Multi-wavelength Pulse Amplitude Modulated fluorometry (Phyto-PAM) reveals differential effects of ultraviolet radiation on the photosynthetic physiology of phytoplankton pigment groups

2016 ◽  
Vol 62 (1) ◽  
pp. 72-86 ◽  
Author(s):  
Laura Beecraft ◽  
Sue B. Watson ◽  
Ralph E. H. Smith
Keyword(s):  
Ultraviolet Radiation ◽  
Pulse Amplitude ◽  
Phytoplankton Pigment ◽  
Differential Effects ◽  
Photosynthetic Physiology ◽  
Multi Wavelength

scholarly journals Differential effects of ultraviolet radiation and oxidative aging on bio-modified binders

Fuel ◽  
2019 ◽  
Vol 251 ◽  
pp. 45-56 ◽  
Author(s):  
Shahrzad Hosseinnezhad ◽  
Mehdi Zadshir ◽  
Xiaokong Yu ◽  
Huiming Yin ◽  
Brajendra K. Sharma ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Differential Effects ◽  
Oxidative Aging ◽  
Modified Binders

scholarly journals Sensitivity of freshwater macrophytes to UV radiation: relationship to depth zonation in an oligotrophic New Zealand lake

2001 ◽  
Vol 52 (7) ◽  
pp. 1023 ◽  
Author(s):  
Rowena Rae ◽  
Rowena Rae ◽  
Dieter Hanelt ◽  
Dieter Hanelt ◽  
Ian Hawes ◽  
...  
Keyword(s):  
New Zealand ◽  
Ultraviolet Radiation ◽  
Vascular Plants ◽  
Pulse Amplitude ◽  
Vertical Zonation ◽  
Low Light ◽  
Freshwater Macrophytes ◽  
Protection Strategies ◽  
Depth Zonation ◽  
Characean Algae

The ultraviolet radiation (UVR) responses of photosynthesis by two freshwater vascular plants, Potamogeton cheesemanii and Isoetes alpinus, and the characean algae Chara fibrosa and C. corallina in Lake Coleridge, New Zealand, were investigated. Experiments comprised 4–5 h of exposure to different UV wavelengths followed by 17 h of recovery in low light. Photosynthetic competence was assessed by pulse-amplitude-modulated fluorometry. The four species showed different sensitivities to UVR, which were consistent with their upper depth limits. The shallowest-growing species, P. cheesemanii, was uninhibited by UVR, whereas after 5 h of exposure to UVR, inhibition of 15%, 38% and 48% was measured for I. alpinus, C. fibrosaand C. corallinacollected from 4 m, 6.2 m and 16.5 m, respectively. Not all plants recovered fully from UVR inhibition. Plants from upper and lower depths of their growth range did not generally differ in inhibition sustained or ability to recover photosynthesis. The species with greatest tolerance of UVR also contained the highest concentrations of UVR-absorbing pigments. Freshwater macrophytes have differing abilities to tolerate UVR exposure through repair and/or protection strategies and these may be related to their vertical zonation.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Differential effects of bismuth sub-salicylate (BSS) in acute non-cholera watery diarrhea in Bangladeshi children

2001 ◽  
Vol 120 (5) ◽  
pp. A215-A215
Author(s):  
P BARDHAN ◽  
S HUQ ◽  
S SARKER ◽  
D MAHALANABIS ◽  
K GYR
Keyword(s):  
Watery Diarrhea ◽  
Differential Effects

CCK-1 and CCK-2 receptors mediate differential effects of cholecystokinin on the motor activity of distal colon

2001 ◽  
Vol 120 (5) ◽  
pp. A173-A174
Author(s):  
F BASCHIERA ◽  
C BLANDIZZI ◽  
M FOMAI ◽  
M TACCA
Keyword(s):  
Motor Activity ◽  
Distal Colon ◽  
Differential Effects
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