| Records |
Author  |
Alves-Simoes, M.; Coleman, G.; Canal, M. |
| Title |
Effects of type of light on mouse circadian behaviour and stress levels |
Type |
Journal Article |
| Year |
2015 |
Publication |
Laboratory Animals |
Abbreviated Journal |
Lab. Anim. |
| Volume |
50 |
Issue |
1 |
Pages |
21-29 |
| Keywords |
Animals; mouse; albino; pigmented; fluorescent light; LED light; Circadian Rhythm |
| Abstract |
Light is the principal synchronizing environmental factor for the biological clock. Light quantity (intensity), and light quality (type of light source) can have different effects. The aim of this study was to determine the effects of the type of light experienced from the time of birth on mouse growth, circadian behaviour and stress levels. We raised pigmented and albino mice under 24 h light–dark cycles of either fluorescent or white light-emitting diode (LED) light source during the suckling stage, and the animals were then exposed to various light environments after weaning and their growth rate, locomotor activity and plasma corticosterone concentration were measured. We found that the type of light the animals were exposed to did not affect the animals’ growth rates or stress levels. However, we observed significant effects on the expression of the locomotor activity rhythm under low contrast light–dark cycles in pigmented mice, and under constant light in both albino and pigmented mice. These results highlight the importance of environmental light quality (light source) on circadian behavioural rhythms, and the need for close monitoring of light environments in animal facilities. |
| Address |
University of Manchester, Faculty of Life Sciences, AV Hill Building, Oxford Road, Manchester M13 9PT, UK. Email: maria.canal{at}manchester.ac.uk |
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| Publisher |
SAGE |
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| Language |
English |
Summary Language |
English |
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IDA @ john @ |
Serial |
1177 |
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| Author |
Alzahrani, H.S.; Khuu, S.K.; Roy, M. |
| Title |
Modelling the effect of commercially available blue-blocking lenses on visual and non-visual functions |
Type |
Journal Article |
| Year |
2019 |
Publication |
Clinical & Experimental Optometry |
Abbreviated Journal |
Clin Exp Optom |
| Volume |
in press |
Issue |
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Pages |
cxo.12959 |
| Keywords |
Human Health; blue-blocking lenses; non-visual functions; transmittance; visual functions |
| Abstract |
BACKGROUND: Blue-blocking lenses (BBLs) are marketed as providing retinal protection from acute and cumulative exposure to blue light over time. The selective reduction in visible wavelengths transmitted through BBLs is known to influence the photosensitivity of retinal photoreceptors, which affects both visual and non-visual functions. This study measured the spectral transmittance of BBLs and evaluated their effect on blue perception, scotopic vision, circadian rhythm, and protection from photochemical retinal damage. METHODS: Seven different types of BBLs from six manufacturers and untinted control lenses with three different powers (+2.00 D, -2.00 D and Plano) were evaluated. The whiteness index of BBLs used in this study was calculated using Commission International de l'Eclairage (CIE) Standard Illuminates D65, and CIE 1964 Standard with a 2 degrees Observer. The protective qualities of BBLs and their effect on blue perception, scotopic vision, and circadian rhythm were evaluated based on their spectral transmittance, which was measured with a Cary 5,000 UV-Vis-NIR spectrophotometer. RESULTS: BBLs were found to reduce blue light (400-500 nm) by 6-43 per cent, providing significant protection from photochemical retinal damage compared to control lenses (p </= 0.05). All BBLs were capable of reducing the perception of blue colours, scotopic sensitivities and circadian sensitivities by 5-36 per cent, 5-24 per cent, and 4-27 per cent, respectively depending on the brand and power of the lens. CONCLUSION: BBLs can provide some protection to the human eye from photochemical retinal damage by reducing a portion of blue light that may affect visual and non-visual performances, such as those critical to scotopic vision, blue perception, and circadian rhythm. |
| Address |
School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia |
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English |
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0816-4622 |
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PMID:31441122 |
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no |
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GFZ @ kyba @ |
Serial |
2654 |
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| Author |
Amano, T.; Ripperger, J.A.; Albrecht, U. |
| Title |
Changing the light schedule in late pregnancy alters birth timing in mice |
Type |
Journal Article |
| Year |
2020 |
Publication |
Theriogenology |
Abbreviated Journal |
Theriogenology |
| Volume |
in press |
Issue |
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Pages |
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| Keywords |
Animals |
| Abstract |
In rats, birth timing is affected by changes in the light schedule until the middle of the pregnancy period. This phenomenon can be used to control birth timing in the animal industry and/or clinical fields. However, changes in the light schedule until the middle of the pregnancy period can damage the fetus by affecting the development of the major organs. Thus, we compared birth timing in mice kept under a 12-h light/12-h darkness schedule (L/D) throughout pregnancy with that of mice kept under a light schedule that changed from L/D to constant light (L/L) or constant darkness (D/D) from day 17.5 of pregnancy, the latter phase of the pregnancy period. On average, the pregnancy period was longer in D/D mice (19.9 days) than L/L or L/D mice (19.5 and 19.3 days, respectively, P < 0.05), confirming that light schedule affects birth timing. The average number of newborns was the same in L/L, L/D, and D/D mice (7.5, 7.8, and 7.9, respectively), but the average newborn weight of L/L mice (1.3 g) was lower than that of L/D and D/D mice (both 1.4 g, P < 0.05), indicating that constant light has detrimental effects on fetus growth. However, the percentage of dead newborns was the same between L/L, L/D, and D/D mice (11.1, 10.6, and 3.6%, respectively). The serum progesterone level on day 18.5 of pregnancy in L/D mice was 42.8 ng/ml, lower (P < 0.05) than that of D/D mice (65.3 ng/ml), suggesting that light schedule affects luteolysis. The average pregnancy period of mice lacking a circadian clock kept under D/D conditions from day 17.5 of pregnancy (KO D/D) (20.3 days) was delayed compared with wild-type (WT) D/D mice (P < 0.05). However, the average number of newborns, percentage of births with dead pups, and weight per newborn of KO D/D mice (7.6, 3.6%, and 1.4 g, respectively) were the same as WT mice kept under D/D conditions. A direct effect of the circadian clock on the mechanism(s) regulating birth timing was questionable, as the lighter average weight per KO fetus (0.6 g) versus WT fetus (0.7 g) on day 17.5 of pregnancy might have caused the delay in birth. The range of birth timing in KO D/D mice was the same as that of WT D/D mice, indicating that the circadian clock does not concentrate births at one time. |
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0093691X |
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no |
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GFZ @ kyba @ |
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2943 |
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| Author |
Amaral, S.; Câmara, G.; Monteiro, A.M.V.; Quintanilha, J.A.; Elvidge, C.D. |
| Title |
Estimating population and energy consumption in Brazilian Amazonia using DMSP night-time satellite data |
Type |
Journal Article |
| Year |
2005 |
Publication |
Computers, Environment and Urban Systems |
Abbreviated Journal |
Computers, Environment and Urban Systems |
| Volume |
29 |
Issue |
2 |
Pages |
179-195 |
| Keywords |
Remote Sensing |
| Abstract |
This paper describes a methodology to assess the evidence of human presence and humanactivities in the Brazilian Amazonia region using DMSP/OLS night-time satellite sensorimagery. It consists on exploring the potential of the sensor data for regional studies analysingthe correlation between DMSP night-time light foci and population, and the correlation be-tween DMSP night-time light foci and electrical power consumption. In the mosaic of DMSP/OLS night-time light imagery from September 1999, 248 towns were detected from a total of749municıpiosin Amazonia. It was found that the night-time light foci were related to human presence in the region, including urban settlements, mining, industries, and civil construction,observed in ancillary Landsat TM and JERS imagery data. The analysis considering only thestate of Para revealed a linear relation (R2¼0:79) between urban population from the 1996census data and DMSP night-time light foci. Similarly, electrical power consumption for 1999was linearly correlated with DMSP night-time light foci. Thus the DMSP/OLS imagery can beused as an indicator of human presence in the analysis of spatial–temporal patterns in theAmazonia region. These results are very useful considering the continental dimension ofAmazonia, the absence of demographic information between the official population census(every 10 years), and the dynamics and complexity of human activities in the region. ThereforeDMSP night-time light foci are a valuable data source for global studies, modelling, and planning activities when the human dimension must be considered throughout Amazonia. |
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0198-9715 |
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GFZ @ kyba @ |
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2221 |
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| Author |
Amaral, S.; Monteiro, A.M.V.; Camara, G.; Quintanilha, J.A. |
| Title |
DMSP/OLS night-time light imagery for urban population estimates in the Brazilian Amazon |
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Journal Article |
| Year |
2006 |
Publication |
International Journal of Remote Sensing |
Abbreviated Journal |
International Journal of Remote Sensing |
| Volume |
27 |
Issue |
5 |
Pages |
855-870 |
| Keywords |
Remote Sensing |
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0143-1161 |
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LoNNe @ kagoburian @ |
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701 |
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