Electrical and Optical Properties of Indium and Lead Co-Doped Cd0.9Zn0.1Te

We have investigated the electrical and optical properties of Cd0.9Zn0.1Te:(In,Pb) wafers obtained from the tip, middle, and tail of the same ingot grown by modified vertical Bridgman method using I-V measurement, Hall measurement, IR Transmittance, IR Microscopy and Photoluminescence (PL) spectroscopy. I-V results show that the resistivity of the tip, middle, and tail wafers are 1.8 × 1010, 1.21 × 109, and 1.2 × 1010 Ω·cm, respectively, reflecting native deep level defects dominating in tip and tail wafers for high resistivity compared to the middle part. Hall measurement shows the conductivity type changes from n at the tip to p at the tail in the growth direction. IR Transmittance for tail, middle, and tip is about 58.3%, 55.5%, and 54.1%, respectively. IR microscopy shows the density of Te/inclusions at tip, middle, and tail are 1 × 103, 6 × 102 and 15 × 103/cm2 respectively. Photoluminescence (PL) spectra reflect that neutral acceptor exciton (A0,X) and neutral donor exciton (D0,X) of tip and tail wafers have high intensity corresponding to their high resistivity compared to the middle wafer, which has resistivity a little lower. These types of materials have a large number of applications in radiation detection.

Label-Free, Real-Time Measurement of Metabolism of Adherent and Suspended Single Cells by In-Cell Fourier Transform Infrared Microspectroscopy

We used infrared (IR) microscopy to monitor in real-time the metabolic turnover of individual mammalian cells in morphologically different states. By relying on the intrinsic absorption of mid-IR light by molecular components, we could discriminate the metabolism of adherent cells as compared to suspended cells. We identified major biochemical differences between the two cellular states, whereby only adherent cells appeared to rely heavily on glycolytic turnover and lactic fermentation. We also report spectroscopic variations that appear as spectral oscillations in the IR domain, observed only when using synchrotron infrared radiation. We propose that this effect could be used as a reporter of the cellular conditions. Our results are instrumental in establishing IR microscopy as a label-free method for real-time metabolic studies of individual cells in different morphological states, and in more complex cellular ensembles.

High-power Terahertz Waves for a Recycle System of Amyloid Fibrils

Recycling of persistent materials is one of most important subjects to be addressed towards the sustainable society. Amyloid fibril is such a tough biomaterial that can be designed for various industrial applications, and it is usually difficult to dissociate the once made fibrous conformation due to the cross β-sheet stacks. We propose here a unique but versatile approach to handle the fibril formation by using two-kinds of high-power terahertz waves. Lysozyme and β2-microglobulin peptide fragment were employed as model samples, and those fibrils were clearly disaggregated accompanied by decrease of β-sheets and increase of α-helices by the irradiation of 5.3 THz free electron laser tuned to 56 μm, as shown by infrared (IR) microscopy and scanning-electron microscopy (SEM). In contrast, those fibrous conformations were reversely self-associated by the irradiation of 0.42 THz wave tuned to 720 μm from gyrotron, as shown by optical and IR microscopies, SEM, and small-angle X-ray scattering. The overall reaction is performed at room temperature within 30 min without external heating and high-pressures. Therefore, amyloid fibrils can be dissociated and associated under the proper far-infrared radiation conditions, which inspires a sustainable recycling system of fibrous biomaterials.

Application of microimaging to diffusion studies in nanoporous materials

Microimaging on the basis of, respectively, interference microscopy and IR microscopy permit the observation of the distribution of guest molecules in nanoporous solids and their variation with time. Thus attainable knowledge of both concentration gradients and diffusion fluxes provides direct access to the underlying diffusion phenomena. This includes, in particular, the measurement of transport diffusion under transient, i. e. under non-equilibrium conditions, and of self- or tracer diffusion on considering the rate of tracer exchange. Correlating the difference in guest concentration close to the external surface to its equilibrium value with the influx into the nanoporous solid, microimaging does as well allow the direct determination of surface resistances. Examples illustrating the variety of information thus attainable include the comparison of mass transfer under equilibrium and non-equilibrium conditions, single- and multicomponent diffusion and chemical reactions. They, finally, introduce into the potentials of microimaging for an in-depth study of mass transfer in mixed-matrix membranes. This tutorial review may serve as first introduction into the topic. Further references are linked for the interested reader.

All-digital histopathology by infrared-optical hybrid microscopy

Optical microscopy for biomedical samples requires expertise in staining to visualize structure and composition. Midinfrared (mid-IR) spectroscopic imaging offers label-free molecular recording and virtual staining by probing fundamental vibrational modes of molecular components. This quantitative signal can be combined with machine learning to enable microscopy in diverse fields from cancer diagnoses to forensics. However, absorption of IR light by common optical imaging components makes mid-IR light incompatible with modern optical microscopy and almost all biomedical research and clinical workflows. Here we conceptualize an IR-optical hybrid (IR-OH) approach that sensitively measures molecular composition based on an optical microscope with wide-field interferometric detection of absorption-induced sample expansion. We demonstrate that IR-OH exceeds state-of-the-art IR microscopy in coverage (10-fold), spatial resolution (fourfold), and spectral consistency (by mitigating the effects of scattering). The combined impact of these advances allows full slide infrared absorption images of unstained breast tissue sections on a visible microscope platform. We further show that automated histopathologic segmentation and generation of computationally stained (stainless) images is possible, resolving morphological features in both color and spatial detail comparable to current pathology protocols but without stains or human interpretation. IR-OH is compatible with clinical and research pathology practice and could make for a cost-effective alternative to conventional stain-based protocols for stainless, all-digital pathology.