Diagnostic of electromagnetic conditions in space using cosmic rays

The method of spectrographic global survey was used to study the time variations in parameters of cosmic ray (CR) pitch angle anisotropy and their relationship with the variations of some solar wind characteristics under different electromagnetic conditions in interplanetary space. A classification is made of the conditions that are accompanied by the increase in CR anisotropy

Diurnal variations of cosmic ray geomagnetic cut-off threshold rigidities

The spectrographic global survey method was used to investigate the rigidity variations Rc of geomagnetic cut-off as a function of local time and the level of geomagnetic disturbance for a number of stations of the world wide network. It is shown that geomagnetic cut-off threshold rigidities undergo diurnal variations. The diurnal wave amplitude decreases with increasing threshold rigidity Rc, and the wave maximum occurs at 2 to 4 hr LT. The amplitude of diurnal variations increases with increasing geomagnetic activity. The results agree with those from trajectory calculations made for an asymmetric model of the magnetosphere during different geomagnetic disturbance conditions

Methods for optical skin clearing in molecular optical imaging in dermatology

This short review describes recent progress in using optical clearing (OC) technique in skin studies. Optical clear-ing is an efficient tool for enhancing the probing depth and data quality in multiphoton microscopy and Raman spec-troscopy. Here, we discuss the main mechanisms of OC, its safety, advantages, and limitations. The data on the OC effect on the skin water content are presented. It was demonstrated that 70% glycerol and 100% OmnipaqueTM 300 reduce the water content in the skin. Both OC agents (OCAs) significantly affect the strongly bound and weakly bound water. However, OmnipaqueTM 300 causes considerably less skin dehydration than glycerol. In addition, the results of examination of the OC effect on autofluorescence in two-photon excitation and background fluorescence in Raman scattering at different skin depths are presented. It is shown that OmnipaqueTM 300 is a promising OCA due to its ability to reduce background fluo-rescence in the upper skin layers. The possibility of multimodal imaging combining optical methods and OC technique is discussed

A comparative study of ex vivo skin optical clearing using two-photon microscopy

Multiphoton tomography (MPT) is a prospective tool for imaging the skin structure. Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (OmnipaqueTM) at different concentrations, which exhibit different osmotic properties. The results show that a topical application of glycerol or OmnipaqueTM solutions onto the skin for 60 min significantly improved the depth and contrast of the MPT signals. By utilizing 40%, 60% and 100% glycerol, and 60% and 100% OmnipaqueTM it was demonstrated that both agents improve autofluorescence and SHG (second harmonic generation) signals from the skin. At the applied concentrations and agent time exposure, glycerol is more effective than OmnipaqueTM. However, tissue shrinkage and cell morphology changes were found for highly concentrated glycerol solutions. OmnipaqueTM, on the contrary, increases the safety and has no or minimal tissue shrinkage during the optical clearing process. Moreover OmnipaqueTM allows for robust multimodal optical/X-ray imaging with automatically matched optically cleared and X-ray contrasted tissue volumes. These findings make OmnipaqueTM more prospective than glycerol for some particular application

Confocal Raman microscopy supported by optical clearing treatment of the skin - influence on collagen hydration

Confocal Raman microscopy (CRM) is employed to study the skin physiology, drug permeation and skin disease monitoring. In order to increase the depth of investigations, the effect of optical clearing was observed on porcine ear skin ex vivo. The optical clearing agents (OCAs) glycerol and iohexol (Omnipaque™) were applied to the porcine ear skin and investigated by CRM after 30 and 60 min of treatment. The extent of optical clearing by utilizing concentrations of 70% glycerol and 100% Omnipaque™ was evaluated. The intensity of the skin-related Raman peaks significantly increased starting from the depth 160 µm for Omnipaque™ and 40 µm for glycerol (p  ≤  0.05) after 60 min of treatment. The OCAs' influence on the collagen hydration in the deep-located dermis was investigated. Both OCAs induce skin dehydration, but the effect of glycerol treatment (30 min and 60 min) is stronger. The obtained results demonstrate that with increasing the treatment time, both glycerol and Omnipaque™ solutions improve the optical clearing of porcine skin making the deep-located dermal regions able for investigations. At the used concentrations and time intervals, glycerol is more effective than Omnipaque™. However, Omnipaque™ is more promising than glycerol for future in vivo applications as it is an already approved pharmaceutic substance without any known impact on the skin structure

Confocal Raman microscopy supported by optical clearing treatment of the skin - influence on collagen hydration

Confocal Raman microscopy (CRM) is employed to study the skin physiology, drug permeation and skin disease monitoring. In order to increase the depth of investigations, the effect of optical clearing was observed on porcine ear skin ex vivo. The optical clearing agents (OCAs) glycerol and iohexol (Omnipaque™) were applied to the porcine ear skin and investigated by CRM after 30 and 60 min of treatment. The extent of optical clearing by utilizing concentrations of 70% glycerol and 100% Omnipaque™ was evaluated. The intensity of the skin-related Raman peaks significantly increased starting from the depth 160 µm for Omnipaque™ and 40 µm for glycerol (p  ≤  0.05) after 60 min of treatment. The OCAs' influence on the collagen hydration in the deep-located dermis was investigated. Both OCAs induce skin dehydration, but the effect of glycerol treatment (30 min and 60 min) is stronger. The obtained results demonstrate that with increasing the treatment time, both glycerol and Omnipaque™ solutions improve the optical clearing of porcine skin making the deep-located dermal regions able for investigations. At the used concentrations and time intervals, glycerol is more effective than Omnipaque™. However, Omnipaque™ is more promising than glycerol for future in vivo applications as it is an already approved pharmaceutic substance without any known impact on the skin structure

A comparative study of ex vivo skin optical clearing using two-photon microscopy

Multiphoton tomography (MPT) is a prospective tool for imaging the skin structure. Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (OmnipaqueTM) at different concentrations, which exhibit different osmotic properties. The results show that a topical application of glycerol or OmnipaqueTM solutions onto the skin for 60 min significantly improved the depth and contrast of the MPT signals. By utilizing 40%, 60% and 100% glycerol, and 60% and 100% OmnipaqueTM it was demonstrated that both agents improve autofluorescence and SHG (second harmonic generation) signals from the skin. At the applied concentrations and agent time exposure, glycerol is more effective than OmnipaqueTM. However, tissue shrinkage and cell morphology changes were found for highly concentrated glycerol solutions. OmnipaqueTM, on the contrary, increases the safety and has no or minimal tissue shrinkage during the optical clearing process. Moreover OmnipaqueTM allows for robust multimodal optical/X-ray imaging with automatically matched optically cleared and X-ray contrasted tissue volumes. These findings make OmnipaqueTM more prospective than glycerol for some particular application