Scalp hypothermia as a preventative measure for chemotherapy-induced alopecia: a review of controlled clinical trials.

Chemotherapy-induced alopecia (CIA) is a temporary, yet psychologically devastating form of hair loss that affects 65% of patients receiving cancer chemotherapy. In the 1970s, scalp hypothermia was introduced as a preventative measure against the development of CIA. Numerous studies provide evidence for the effectiveness of scalp cooling to prevent CIA, although results varied because of differences in chemotherapy regimen, cooling technique, mode of administration and patient factors. However, many of the existing studies are uncontrolled or consist of small sample sizes, and data from randomized, randomized studies are limited. To date, no clear guidelines have been established for optimum scalp cooling use as a treatment modality and its efficacy remain unknown. Nonetheless, scalp cooling remains the most widely utilized method for the prevention of CIA, and in December 2015, the United States Food and Drug Administration (FDA) cleared the DigniCap® Scalp Cooling System (Dignitana AB, Sweden) for marketing and the Orbis from Paxman® Coolers Ltd. received clearance in 2017. This literature review is one of the first to provide up-to-date review and side-by-side comparisons of controlled and randomized clinical trials (CCTs and RCTs) evaluating scalp hypothermia for the prevention of CIA. Our analyses of CCTs and RCTs to date show that scalp hypothermia is effective in reducing the occurrence rate of CIA, by 2.7-fold in the CCTs and 3.9-fold in the RCTs. These results suggest that scalp hypothermia represents an effective preventative measure for CIA, and provide guidance for management of anticipated alopecia following chemotherapy and for future investigations.

Measuring Newtonian viscosity from the phase of reflected ultrasonic shear wave.

In this paper, an acoustic shear impedance model is employed to obtain a relation between the viscosity of a Newtonian fluid and phase characteristics of ultrasonic shear wave reflection from a solid-fluid interface. The phase and magnitude of the reflection coefficient can be decoupled in this model. The decoupling allows an independent relation between the acoustic shear impedance (viscosity-density product) and phase of the reflection coefficient. The model was experimentally verified for different fluid-solid combinations. Comparison of the results with the commonly used absolute reflection coefficient method demonstrates that phase measurement provides improved measurements.

Design of an achromatic beam splitter comprising a dielectric multilayer stack.

The inverse transmittance (1/T) of a quarterwave all dielectric multilayer stack is expressed as a mixed series in sinø and cosø, where ø = (pi/2)[(lambda - lambda(0))/ lambda] and lambda(0) is the reference wavelength. This expression has been used to design achromatic beam splitters for the visible and near IR regions having different reflectance (R) to transmittance (T) ratios (e.g. R:T = 70:30, 30:70, 50:50, 60:40, 40:60, etc.). The theoretical design places emphasis on the selection of refractive indices which can be realized in practice.

Periodic dielectric multifilm stack with symmetrical period having films of three different refractive indices: use as a heat reflecting mirror.

Results of the theoretical computations of reflectance and transmittance values of periodic dielectric multifilm stacks with symmetrical periods, each consisting of films of three different refractive indices, are reported. The analysis yields good estimates of the bandwidths of the low reflectance and high reflectance zones for different compositions of the periodic structures, and one of the structures offers the possibility of use as a heat reflecting mirror. This particular structure when combined with a previously published design gives a heat reflecting mirror design with good spectral characteristics and seems to be relatively easy to fabricate, while the earlier design, which exhibits somewhat superior spectral characteristics, appears to be extremely difficult to fabricate.

General expression for the reflectance of an all-dielectric multilayer stack.

A converted characteristic matrix method has been used to derive a generalized expression for reflectance R (for wavelength lambda at normal incidence) of an all-dielectric multilayer stack consisting of K layers of refractive indices n(1),n(2),n(3)... n(k-1),n(k) having quarterwave thicknesses at the monitoring wavelength lambda(0). The expression thus derived is of the form R = Sigma(K)(N=0)(P(N) tan(2N)?)/(Q(N)tan(2N)?), where P(N) and Q(N) are functions of refractive indices and their interdependence is expressed by the relation (Q(N) - P(N))/(4n(S)) = (K!)/N!(K - N)!]. This expression shows that R is a function of (i) the refractive indices of the various layers in the multilayer structure and (ii) the parameter ? = {(Pi/2) [(lambda - lambda(0))/lambda]} which assumes positive or negative values depending on whether lambda < lambda(0) or A > lambda(0) such that within limits of acceptable variations (Deltalambda) in lambda(0), R remains unaffected at +/-?. An outcome of this analysis is that it can be used in identifying, to a limited extent, the structure of an unknown optical coating once the experimentally observed parameters R and T are known.