The optimal size of spherical silver nanoparticles (AgNPs) for off-resonance surface-enhanced Raman scattering (SERS) was found to be ∼50 nm based on the equivalent Ag content in AgNP colloids. It is understood that the SERS intensity of adsorbates on the surface of metal nanoparticles is dependent on the size and shape of the particles of interest. Herein, we report a seeded growth mechanism for the formation of silver nanoparticles that allows superior control over the size of the resultant nanoparticles with relatively low polydispersity. The high degree of size control allows for a better understanding of the study of the effect of particle size on SERS intensity. The Raman study performed here employed a long-wavelength excitation (785 nm) so as to avoid photochemical degradation of adsorbed species and photochemical transformation under intense excitation. Under these experimental conditions, it was found that the optimal size of AgNPs for providing a maximum SERS intensity of adsorbed R6G is ∼50−60 nm, a result that is expected to extend to other adsorbates as well.

Women are underrepresented in STEM and in entrepreneurship but are rare in STEM entrepreneurship. A gender-sensitive entrepreneurship education and peer mentoring program for women engineering and computer science students was developed to provide classroom instruction, experiential learning, and support to a small group of students. This paper reports on the experiences of student peer mentors in the program, in terms of entrepreneurial self-efficacy (ESE) and entrepreneurial intent (EI). Qualitative methods were adopted for this study. Student mentors were interviewed about their experiences and reported increased perceptions of entrepreneurial self-efficacy, a greater awareness of diversity and gender issues, and a changed perspective on problem solving and life in general. Student mentors reported a distinct interest in becoming an entrepreneur at "some time" in their lives, although not necessarily immediately upon graduation.

The present paper demonstrates an antibody-free, robust, fast, and portable platform for detection of leukemia cells using Raman spectroscopy with a 785-nm laser diode coupled to a hollow core photonic crystal (HC-PCF) containing silver nanoparticles. Acute myeloid leukemia is one of the most common bone marrow cancers in children and youths. Clinical studies suggest that early diagnosis and remission evaluation of myoblasts in the bone marrow are pivotal for improving patient survival. However, the current protocols for leukemic cells detection involve the use of expensive antibodies and flow cytometers. Thus, we have developed a new technology for detection of leukemia cells up to 300 cells/ml using a compact fiber HC-PCF, which offers a novel alternative to existing clinical standards. Furthermore, we were also able to accurately distinguish live, apoptotic and necrotic leukemic cells.

Price declines and volume growth of concentrated photovoltaic (CPV) systems are analysed using the learning curve methodology and compared with other forms of solar electricity generation. Logarithmic regression analysis determines a learning rate of 18% for CPV systems with 90% confidence of that rate being between 14 and 22%, which is higher than the learning rates of other solar generation systems (11% for CSP and 12 to 14% for PV). Current CPV system prices are competitive with PV and CSP, which, when combined with the higher learning rate, indicates that CPV is likely to further improve its marketability. A target price of 1 $/W in 2020 could be achieved with a compound growth rate of 67% for the total deployed volume between 2014 and 2020, which would realize a cumulative deployed volume of 7900 MW. Other projections of deployment volumes from commercial sources are converted using the learning rate into future price scenarios, resulting in predicted prices in the range of 1.1 to 1.3 $/W in 2020.

We demonstrate coherent anti-Stokes Raman scattering (CARS) microscopy of lipid-rich structures using a single unamplified femtosecond Ti:sapphire laser and a photonic crystal fiber (PCF) with two closely lying zero dispersion wavelengths (ZDW) for the Stokes source. The primary enabling factor for the fast data acquisition (84 micros per pixel) in the proof-of-principle CARS images, is the low noise supercontinuum (SC) generated in this type of PCF, in contrast to SC generated in a PCF with one ZDW. The dependence of the Stokes pulse on average input power, pump wavelength, pulse duration and polarization is experimentally characterized. We show that it is possible to control the spectral shape of the SC by tuning the pump wavelength of the input pulse and the consequence for CARS microscopy is discussed.