We develop a method to determine size and size distribution (30-150 nm) of polydisperse nanoparticles using a laser ablation/ ionization time-of-flight single-particle mass spectrometer that extends the work first described by Reents and Ge. We found a composition independent "power law" dependence between the total peak area and original particle volume that enables one to determine particle volume directly from a particles mass spectrum. This power-law relationship suggests that some ions ablated and ionized from a particle are selectively lost during transport from the laser ablation/ionization region to the detector. A numerical calculation of ion trajectories shows that ion loss is highly dependent on the initial kinetic energy of ions. We show that the size-dependent energetic ions formed by the laser-particle interaction lead to powerlaw relationship between the cube root of peak area and particle diameter. The results demonstrate that particle size distributions measured with the mass spectrometer are in good agreement with those measured with a scanning mobility particle sizer.

The light absorption of silica nanoparticles generated in a flame has been measured in visible light. It was revealed that the frequency dependence of the light absorption coefficient is nonexponential. Its absolute value in the forbidden band was found to be unusually high. This behavior of light absorption is ascribed to a narrowing of the energy gap due to a high concentration of structural defects that appear during particle generation and growth at high temperatures.

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Using 63 bit simplex coding we demonstrate enhanced performance in Raman-based distributed temperature sensors using low-power (80 mW) laser diodes. Achieved 5.8 dB improvement in dynamic range allows for temperature sensing over 17 km with 15m/5K spatial/temperature resolution.

The energy accommodation coefficient (EAC), which is used to characterize gas-surface interactions, was experimentally estimated at high temperatures. A method utilizing laser irradiation to heat up nanoparticles that are generated in a flame was proposed. From the obtained dependence of particle temperature upon laser power, the EAC was derived to be approximately equal to 0.005, which agrees nicely with our recent rigorous theoretical result. It indicates that the efficiency of heat transfer between gas and particles is sufficiently small in high temperature system at large Knudsen numbers.

Cancer secretome is a reservoir for aberrant glycosylation. How therapies alter this post-translational cancer hallmark and the consequences thereof remain elusive. Here we show that an elevated secretome fucosylation is a pan-cancer signature of both response and resistance to multiple targeted therapies. Large-scale pharmacogenomics revealed that fucosylation genes display widespread association with resistance to these therapies. In both cancer cell cultures and patients, targeted kinase inhibitors distinctively induced core fucosylation of secreted proteins less than 60 kDa. Label-free proteomics of N-glycoproteomes revealed that fucosylation of the antioxidant PON1 is a critical component of the therapy-induced secretome. Core fucosylation in the Golgi impacts PON1 stability and folding prior to secretion, promoting a more degradation-resistant PON1. Non-specific and PON1-specific secretome de-N-glycosylation both limited the expansion of resistant clones in a tumor regression model. Our findings demonstrate that core fucosylation is a common modification indirectly induced by targeted therapies that paradoxically promotes resistance.

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