RDX Detection with THz Spectroscopy

Spectroscopic analysis in the Terahertz frequency range, providing characteristic “signatures” for explosive and non-explosive materials, is proposed as an efficient and powerful tool for explosive identification. It is demonstrated that spectral responses of materials can be used as fingerprints that distinguish cyclotrimethylenetrinitramine (RDX) from other materials even with simple detectors and a limited number of available frequencies. Detection is performed using a modified least squares approach and multilayer perceptrons that operate on smoothed reflectance spectra. The performance of the detectors is evaluated through application to spectra of RDX and several common materials. A Receiver Operating Characteristic curve analysis demonstrates that our detectors exhibit the desirable properties of high probability of detection and low probability of false alarm.     

Protein thin film machines

We report the first example of microcantilever beams that are reversibly driven by protein thin film machines fueled by cycling the salt concentration of the surrounding solution. We also show that upon the same salinity stimulus the drive can be completely reversed in its direction by introducing a surface coating ligand. Experimental results are throughout discussed within a general yet simple thermodynamic model.     

Two-step hydrolysis of amygdalin in molds

Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35, characterized by extracellular beta-glucosidase activity on cyanogenic glycosides, hydrolyse amygdalin by a two-step reaction mechanism being the first step of hydrolysis, from amygdalin to prunasin, very rapid (15 min) and the second one, from prunasin to mandelonitrile, much slower (120 min).     

Molecular Design and Control Over the Morphology of Self‐Assembled Films on Ionic Substrates

Achieving control over formation of molecular films on insulating substrates is important for designing novel 2D functional materials and devices. To study the main factors governing successful control, organic molecules with interchangeable polar functional groups, a variable length aromatic body, and flexible hydrocarbon chains are designed, synthesized and then deposited on the (001) surfaces of bulk sodium chloride, potassium chloride, and rubidium chloride. The deposited structures are imaged using noncontact atomic force microscopy and modeled using density functional theory. The results show that it is possible to form large‐scale, highly ordered, 2D, porous molecular domains (>10⁴ pores), which are stable at room temperature, and to control the size of the 2D pores. Alternatively, it is possible to form line structures or droplets (through molecular dewetting) by altering the molecular structure or changing the substrate lattice constant. Theoretical calculations explain the balance of the molecule–molecule and molecule–surface interactions and the structure and thermodynamic stability of the grown films.     

Inhibition of Lysine 63 Ubiquitination Prevents the Progression of Renal Fibrosis in Diabetic DBA/2J Mice

Diabetic nephropathy (DN) is the most frequent cause of end-stage renal disease. Tubulointerstitial accumulation of lysine 63 (K63)-ubiquitinated (Ub) proteins is involved in the progression of DN fibrosis and correlates with urinary miR-27b-3p downregulation. We explored the renoprotective effect of an inhibitor of K63-Ub (NSC697923), alone or in combination with the ACE-inhibitor ramipril, in vitro and in vivo. Proximal tubular epithelial cells and diabetic DBA/2J mice were treated with NSC697923 and/or ramipril. K63-Ub protein accumulation along with α-SMA, collagen I and III, FSP-1, vimentin, p16^INK4A expression, SA-α Gal staining, Sirius Red, and PAS staining were measured. Finally, we measured the urinary albumin to creatinine ratio (uACR), and urinary miR-27b-3p expression in mice. NSC697923, both alone and in association with ramipril, in vitro and in vivo inhibited hyperglycemia-induced epithelial to mesenchymal transition by significantly reducing K63-Ub proteins, α-SMA, collagen I, vimentin, FSP-1 expression, and collagen III along with tubulointerstitial and glomerular fibrosis. Treated mice also showed recovery of urinary miR-27b-3p and restored expression of p16^INK4A. Moreover, NSC697923 in combination with ramipril demonstrated a trend in the reduction of uACR. In conclusion, we suggest that selective inhibition of K63-Ub, when combined with the conventional treatment with ACE inhibitors, might represent a novel treatment strategy to prevent the progression of fibrosis and proteinuria in diabetic nephropathy and we propose miR-27b-3p as a biomarker of treatment efficacy.     

Non-contact atomic force microscopy study of hydroxyl groups on the spinel MgAl2O4(100) surface

Atom-resolved non-contact atomic force microscopy (NC-AFM) studies of the magnesium aluminate (MgAl(2)O(4)) surface have revealed that, contrary to expectations, the (100) surface is terminated by an aluminum and oxygen layer. Theoretical studies have suggested that hydrogen plays a strong role in stabilizing this surface through the formation of surface hydroxyl groups, but the previous studies did not discuss in depth the possible H configurations, the diffusion behaviour of hydrogen atoms and how the signature of adsorbed H is reflected in atom-resolved NC-AFM images. In this work, we combine first principles calculations with simulated and experimental NC-AFM images to investigate the role of hydrogen on the MgAl(2)O(4)(100) surface. By means of surface energy calculations based on density functional theory, we show that the presence of hydrogen adsorbed on the surface as hydroxyl groups is strongly predicted by surface stability considerations at all relevant partial pressures of H(2) and O(2). We then address the question of how such adsorbed hydrogen atoms are reflected in simulated NC-AFM images for the most stable surface hydroxyl groups, and compare with experimental atom-resolved NC-AFM data. In the appendices we provide details of the methods used to simulate NC-AFM using first principles methods and a virtual AFM.     

Review of Moisture and Liquid Detection and Mapping using Terahertz Imaging

The relatively high permittivity of liquid water compared to other materials in the Terahertz (THz) range enables a contrast mechanism for the detection and imaging of moisture. In this paper, spatial mapping of moisture and liquid detection by THz imaging is reviewed. Analysis of the moisture content is discussed in terms of a double Debye model for liquid water and effective medium models for the permittivity of the dry and ‘wet’ materials of interest. Examples from medical applications, forestry products, agriculture/ food products, and polymers are reviewed. Extraction of diffusion rates and diffusion maps from THz images are discussed.