Low-power laser therapy for carpal tunnel syndrome:effective optical power

Low-power laser therapy has been used for the non-surgical treatment of mild to moderate carpal tunnel syndrome,although its efficacy has been a long-standing controversy.The laser parameters in low-power laser therapy are closely related to the laser effect on human tissue.To evaluate the efficacy of low-power laser therapy,laser parameters should be accurately measured and controlled,which has been ignored in previous clinical trials.Here,we report the measurement of the effective optical power of low-power laser therapy for carpal tunnel syndrome.By monitoring the backside reflection and scattering laser power from human skin at the wrist,the effective laser power can be inferred.Using clinical measurements from 30 cases,we found that the effective laser power differed significantly among cases,with the measured laser reflection coefficient ranging from 1.8% to 54%.The reflection coefficient for 36.7% of these 30 cases was in the range of 10–20%,but for 16.7% of cases,it was higher than 40%.Consequently,monitoring the effective optical power during laser irradiation is necessary for the laser therapy of carpal tunnel syndrome.

Re-understanding of land surface albedo and related terms in satellite-based retrievals

Land surface albedo is a critical variable in determining surface energy balance,and regulating climate and ecosystem processes through feedback mechanisms.Therefore,climatic modelers and radiative monitoring require accurate estimates of land surface albedo.With the instrument development,algorithm upgrade,spectral-band-adjustment in wavelength center or band width,and the increasing distinct requirement from diversified communities,various albedo terms have been generated in related satellite-based products.The lack of understanding on the divergence of these terminologies can introduce potential considerable errors in the subsequent applications,or an elevated probability to invert the deduced conclusion.We surveyed the basic concepts of reflectance quantities,retrieval strategies,and models developed since the 1970s,and discuss both strength and opportunity for improvements on land surface albedo extraction,and product generation.In addition,we exemplified the difference of albedo terms using the daily MODIS product(MCD43A)to emphasize the potential risk of the ambiguous usage,over typical IGBP land covers in Northern Kazakhstan.Our investigation shows that relative differences among various albedo terms can reach up to 181%and 50%,while 0.266 and 0.118 of absolute variance respectively in the narrow and broad-band surface albedo,which illuminated cautions against the ambiguous understanding of albedo terminologies or erroneous usage of albedo products.