background: the genus pallisentis is an endoparasitic acanthocephalan inhabit­ing the intestinal walls. hooks and spines of the worm are significant taxonomical and adaptive tools. methods: the parasites were fixed, dehydrated and examined under olym­pus bx 53 microscope with dic attachment, digital camera and cellsens imag­ing system [light microscopy (lm)] and fixed in 2% glutaraldehyde in 0.1...

it is only thirteen years since the scanning electron microscope has been available commercially. yet, even in this short period of time, this instrument has been a powerful tool in the investigation of topography, electrical and magnetic properties, crystal structure, cathodoluminescent characteristics etc. of solid specimens. today, this type of microscope has opened its place alongside the c...

Two symmetrically positioned redox active tyrosine residues are present in the photosystem II (PSII) reaction center. One of them, TyrZ, is oxidized in the ns-micros time scale by P680+ and reduced rapidly (micros to ms) by electrons from the Mn complex. The other one, TyrD, is stable in its oxidized form and seems to play no direct role in enzyme function. Here, we have studied electron donati...

Electron transfer from P+QA-QB to form P+QAQB- was measured in Rhodobacter sphaeroides R-26 reaction centers (RCs) where the native primary quinone, ubiquinone-10 (UQA), was replaced by 2-methyl-3-phytyl-1,4-naphthoquinone (MQA). The native secondary quinone, UQ-10, was retained as UQB. The difference spectrum of the semiquinone MQA- minus UQB- absorption is very similar to that of MQ- minus UQ...

Single gold-tagged epidermal growth factor (EGF) molecules bound to cellular EGF receptors of fixed fibroblast cells were imaged in liquid with a scanning transmission electron microscope (STEM). The cells were placed in buffer solution in a microfluidic device with electron transparent windows inside the vacuum of the electron microscope. A spatial resolution of 4 nm and a pixel dwell time of ...

BACKGROUND AND OBJECTIVES Selective treatment of the retinal pigment epithelium (RPE) by repetitively applying green micros-laser pulses is a new method for retinal diseases associated with a degradation of the RPE, which spares the neural retina. We investigated an alternative approach to realize repetitive micros-laser exposure by rapidly scanning a continuous wave (CW)-laser beam across the ...

introduction: the aim of this study was to investigate the scanning electron microscope (sem) analysis of tooth surface irradiated by different parameters of er:yag laser. methods: 15 caries-free extracted human third molars were used in this study. the teeth were put into 5 groups for laser irradiation as follows: group 1 (power: 2.5 w, energy: 250 mj); group 2(power: 3 w, energy: 300 mj); gro...