A method of characterising a composition of a gemstone comprises irradiating an upper portion and a lower portion of the gemstone with one or more pulses of ultraviolet radiation at a wavelength of substantially 225 nm or less; capturing luminescence emitted by the upper portion of the gemstone and luminescence emitted by the lower portion of the gemstone in one or more time windows having a predetermined relationship with the or each pulse; and comparing properties of the captured luminescence from the upper and lower portions. A composition of the gemstone is characterised, based upon the comparison.

Embodiments described herein generally relate to: sensing and/or authentication using luminescence imaging; diagnostic assays, systems, and related methods; temporal thermal sensing and related methods; and/or to emissive species, such as those excitable by white light, and related systems and methods.

A method is provided for verifying the authenticity of an article which bears a security mark. The method includes irradiating the security mark with a time-varying light source, ascertaining at least one portion of the emissions spectrum of the irradiated security mark with at least one photodetector, determining the photoluminescence lifetime of the security mark by monitoring the time or frequency response of the photodetector, and verifying the authenticity of the article only if the security mark exhibits a photoluminescence which has a lifetime that falls within the range of appropriate values for each portion of the photoluminescence spectrum for which the photoluminescence lifetime of said security mark was ascertained.

An optical detector (1) on an application specific integrated circuit (ASIC) comprises at least one photodiode (5) for receiving incident light and configured to provide at least one diode signal, a modulator (2) configured to provide an AC drive signal and to provide a reference signal associated with the AC drive signal; and a lock-in amplifier (6) configured to receive said at least one diode signal from said at least one photodiode (5) and to receive the reference signal from the modulator (2), and to determine at least one of a phase and an amplitude of said at least one diode signal using the reference signal.

The present invention relates to a method for detecting an amyloid β oligomer which includes a test sample and thioflavin T are brought into contact with each other, fluorescence of the thioflavin T is measured to obtain time-resolved fluorescence spectra, the time-resolved fluorescence spectrum of time period t1 to t2 and the time-resolved fluorescence spectrum of time period t3 to t4 are respectively normalized to obtain normalized spectra (t1<t2≤t3<t4), and determination is made to confirm the presence or absence of an amyloid β oligomer in the test sample on the basis of the two normalized spectra, and shifting of the normalized spectrum of time period t3 to t4 towards the low wavelength side in comparison to the normalized spectrum of time period t1 to t2 indicates the presence of an amyloid β oligomer in the test sample.

Embodiments described herein generally relate to: sensing and/or authentication using luminescence imaging; diagnostic assays, systems, and related methods; temporal thermal sensing and related methods; and/or to emissive species, such as those excitable by white light, and related systems and methods.

Embodiments described herein generally relate to: sensing and/or authentication using luminescence imaging; diagnostic assays, systems, and related methods; temporal thermal sensing and related methods; and/or to emissive species, such as those excitable by white light, and related systems and methods.

Embodiments described herein generally relate to: sensing and/or authentication using luminescence imaging; diagnostic assays, systems, and related methods; temporal thermal sensing and related methods; and/or to emissive species, such as those excitable by white light, and related systems and methods.

The present invention relates to a method for detecting an amyloid β oligomer which includes a test sample and thioflavin T are brought into contact with each other, fluorescence of the thioflavin T is measured to obtain time-resolved fluorescence spectra, the time-resolved fluorescence spectrum of time period t1 to t2 and the time-resolved fluorescence spectrum of time period t3 to t4 are respectively normalized to obtain normalized spectra (t1<t2≤t3<t4), and determination is made to confirm the presence or absence of an amyloid β oligomer in the test sample on the basis of the two normalized spectra, and shifting of the normalized spectrum of time period t3 to t4 towards the low wavelength side in comparison to the normalized spectrum of time period t1 to t2 indicates the presence of an amyloid β oligomer in the test sample.

A diamond evaluation device includes a lightproof enclosure and a platform for supporting a diamond to be evaluated, the platform being transmissive of ultraviolet C (UVC) radiation. At least one source of UVC radiation to irradiate the diamond includes at least one source that is a lower source located below the platform on an opposite side of the platform from the diamond when the diamond is supported by the platform. A light detector detects visible light that is emitted by the diamond at least as phosphorescence after irradiation of the diamond. A display displays a result of detection of the emitted light so as to enable at least distinguishing between emission of phosphorescence that is characteristic of a laboratory-grown diamond, and an absence of phosphorescence that is characteristic of a natural diamond.