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Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) absorbers are considered promising alternatives to commercial thin film technologies including CdTe and Cu(In,Ga)Se2 (CIGSe) owing to the earth abundance and non-toxicity of their constituents. However, to be competitive with the existing technologies, the photovoltaic performance of CZTSSe solar cells needs to be improved beyond the current record conversion efficiency of 12.6%. In this study, nanoscale elemental mapping using Auger nanoprobe microscopy (NanoAuger) and nano secondary ion mass spectrometry (NanoSIMS) are used to provide a clear picture of the compositional variations between the grains and grain boundaries in Cu2ZnSn(S,Se)4 kesterite thin films. NanoAuger measurements revealed that the top surfaces of the grains are coated with a Zn-rich (Zn,Sn)Ox layer. While thick oxide layers were observed at the grain boundaries, their chemical compositions were found to be closer to SnOx. NanoSIMS elemental maps confirmed the presence of excess oxygen deeper within the grain boundary grooves, as a result of air annealing of the CZTSSe films.

The need for high-κ gate dielectrics and metal gates in advanced integrated circuits has reopened the door to Ge and III–V compounds as potential replacements for silicon channels, offering the possibility to further increase the performances of complementary metal oxide semiconductor (CMOS) circuits, as well as adding new functionalities. Yet, a fundamental issue related to high-mobility channels in CMOS circuits is the electrical passivation of their interfaces (i.e., achieving a low density of interface defects) approaching state-of-the-art Si-based devices. Here we discuss promising approaches for the passivation of Ge and III–V compounds and highlight insights obtained by combining experimental characterization techniques with first-principles simulations.

Planar arrays of microwells were fabricated in Silicon on borosilicate glass (pyrex) substrates in order to facilitate live cell fluorescence imaging experiments for cells sequestered inside their own individual microenvironments for incubation and quantification of single cell seceretions. Two methods of deep silicon etching were compared: cryogenic deep reactive ion etching (DRIE) and time multiplexed DIRE (Bosch Process). A 200um Si wafer was bonded to a 500um pyrex substrate. Cryogenic DRIE allowed for the reliable fabrication of 75-100um deep microwells with 60x60um openings across a 10x10mm substrate while the Bosh Process allowed for etching entirely through the Si layer, producing 200um deep microwells with transparent bottoms and steep sidewalls while maintaining the target 60x60um opening geometry.

Monoclonal antibodies are increasingly used in the treatment of cancer due to their enhanced targeting and immune system stimulation properties. Dosage guidelines typically do not account for personal cancer load or metabolism, thereby possibly affecting treatment outcome or causing unwanted side effects. The requirement for an assay that can quickly and precisely measure the concentration of the monoclonal antibody in a serum sample of a patient during therapy is unmet. A bead-based assay with peptide antigen mimetics has been developed to rapidly determine the concentration of antibody drug present in serum specimens with high sensitivity. Alemtuzumab (anti-CD52) and rituximab (anti-CD20) antigen mimetic peptides, as discovered by phage display, were synthesized on 10 um TentaGel resin beads using conventional solid phase peptide synthesis techniques. The beads were modified to allow for multiplexing and microfluidic handling via fluorescent labeling and magnetic functionalization. The antigen-displaying fluoromagnetic particles were incubated with spiked serum samples which allowed free antibody to be captured. Primary antibody detection was performed on alemtuzumab while rituximab detection was used to compensate for non-specific serum binding to the beads. After washing, the beads were incubated with a fluorescently tagged secondary label for detection by flow cytometry. (Results) A fast, low cost, specific assay has been developed with several key techniques which allows detection at low concentration (0.1ug/ml) of spiked samples. Primary to achieving this detection limit was the implementation of a compensation scheme where two antigen mimetic peptides behave linearly (R2=0.996) which enables the calculation of the zero response of the antigen mimetic peptide of interest (alemtuzumab antigen mimetic) while measuring the zero response of the compensatory antigen mimetic peptide (rituximab antigen mimetic) during primary assay measurement. This reduces fluorescence response variation due to variations present due to sample preparation, storage and different patients because of the equivalent interactions these effects have on the compensatory beads. The developed assay is therefore robust against serum variation and enables a lower limit of detection.

Breast conservation therapy is the standard treatment for breast cancer; however, 20-50% of operations have a positive margin leading to secondary procedures. The standard of care to evaluate surgical margins is based on permanent section. Imprint cytology (touch prep) has been used to evaluate surgical samples, but conventional techniques require an experienced cytopathologist for correct interpretation. An automated image screening process has been developed to discern cancer cells from normal epithelial cells. This technique is based on cellularity of the imprint specimen and does not require expertise in cytopathology.A rapid immunofluorescent staining technique coupled with automated microscopy was used to classify specimens as cancer vs. noncancer based on the density of epithelial cells captured on touch prep of tumor cross-sections. The results of the automated analysis vs. a manual screen of ten 20x fields were compared to the pathology interpretation on permanent section.A total of 34 consecutive cases were analyzed: 10 normal cases, and 24 cancer cases. The cross-section specimens for invasive cancer were correctly classified in at least 65% of the cases by using manual microscopy and at least 83% by using automated microscopy. The manual and automated microscopy correlated well for measurements of epithelial cell density (R(2)=0.64); however, the automated microscopy was more accurate.This preliminary study using an automated system for intraoperative interpretation does not require a cytopathologist and shows that rapid, low-resolution imaging can correctly identify cancer cells for invasive carcinoma in surgical specimens. Therefore, automated determination of cellularity in touch prep is a promising technique for future margin interpretation of breast conservation therapy.