search.noResults

search.searching

dataCollection.invalidEmail
note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
Artemia: A Model Specimen


Figure 3 : Examples of camera-microscope setups. (a) Digital SLR camera fi tted with a suitable lens adapted to a trinocular photo-tube with a photo eyepiece 10×. (b) Digital bridge camera with an integrated zoom lens mounted with a vario (zoom) photo ocular 5× to 12.5×. (c) Special microscope camera mounted with a photo eyepiece 10×. (d) Compact digital camera mounted with a monocular tube. (e) Smartphone-adapter (UNIKOP, manufactured by Immunocons Co., Germany) mounted with a stereo microscope. This adapter consists of a variable holder so that smartphones of different sizes can be used.


T e natural color of individuals is infl uenced by the quality of water. When the salt concentration is low, the utilization of oxygen is most eff ective. Over the course of several days some water may evaporate and the concentration of salt will increase in the remaining volume of water. At that point the utilization of oxygen is reduced so that the production of hemoglobin is intensifi ed and the colorization of Artemia is shiſt ed to red. T us, red colorization is an indicator of hypoxemia. In this case an adequate proportion of fresh water should be added. T ese color shiſt s from gray to bronze to reddish can be seen in the image sequences of Figure 4 .


Young larvae showed only a stereotypical movement similar to breast-stroke swimming ( Figure 5a ). At the beginning of the third phase of development (days 4–6), additional asynchrony patterns could be seen comparable with swimming the crawl ( Figure 5b ). In the course of phase 4, some larvae could be observed swimming as a couple showing synchronized formations of movement ( Figure 6 ). Some days later, even looping, forward rolls, and other complex movement patterns could be observed ( Figure 7 ). Aſt er a period of four weeks, only a few individuals survived, and on the 35th day of observation the last animal expired.


14


Digital image processing . Photomicrographs taken from Artemia were also used for introduc- tions to digital image processing. In particular, bright-fi eld images were digitally inverted by use of standard imaging soſt ware so that digital “dark-fi eld” images could be obtained revealing fi ne details with an improved clarity. T e appearance and fascinating appeal of such inverted images was similar to X-ray images ( Figure 8 ). T e appearance of an inverted bright- fi eld image was strongly infl uenced by the exposure and the range of contrast between specimen and background. When photomicrographs were taken in brightfi eld and properly exposed, the background was whitish, and high-density specimens appeared rather dark, leading to a high range of contrast ( Figure 8 ). In underexposed bright-fi eld images the range of contrast was reduced signifi cantly: the background showed a lower brightness and a yellowish or orange tint. T us, the background was no longer black or dark when a digital inversion was carried out. In such images fi ne nuances of density could be revealed such that the appearance of the inverted image ( Figure 9 ) seemed to be similar to (negative) phase contrast. In comparison to real darkfi eld, digital “dark-fi eld” images did not


show the specimens in their natural color, but they were free from typical artifacts oſt en seen in normal dark-fi eld images, such as ultra-bright contours (marginal irradiation) and other eff ects of refl ection caused by a very bright illuminating light, such as blooming and scattering. Similarly, digital “phase- contrast” images were free from typical artifacts associated with true phase-contrast imaging such as haloing and shade-off (further explanations in web source [d]). Suggestions of further experiments . Observations of growth and locomotion can be made with naked eyes even by very young children so that children´s inherent interest in nature can be stimulated when Artemia is presented in classrooms and integrated into lessons (web source [e]). T rough successive microscopic observations of Artemia, young students can be introduced to several principles of scientifi c work. For instance, larvae can be photographed daily, and their body length measured. Since there is a well-defi ned number of individuals, the body length can be averaged for each day of observation, and corresponding standard deviations can be calculated. Based on these data, kinetics of growth can be graphically demonstrated and mathematically described ( Figure 10 ).


www.microscopy-today.com • 2018 July


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76