Adsorption of SARS-CoV-2 Spike (N501Y) RBD to Human Angiotensin-Converting Enzyme 2 at a Lipid/Water Interface.

The receptor binding domain (RBD) of spike proteins plays a crucial role in the process of severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) attachment to the human angiotensin-converting enzyme 2 (ACE2). The N501Y mutation and later mutations introduced extra positive charges on the spike RBD and resulted in higher transmissibility, likely due to stronger binding with the highly negatively charged ACE2. Consequently, many studies have been devoted to understanding the molecular mechanism of spike protein binding with the ACE2 receptor.

Smartphone-Enabled Quantification of Potassium in Blood Plasma.

This work describes a new method for determining K concentration, [K], in blood plasma using a smartphone with a custom-built optical attachment. The method is based on turbidity measurement of blood plasma solutions in the presence of sodium tetraphenylborate, a known potassium precipitating reagent. The images obtained by a smartphone camera are analyzed by a custom image-processing algorithm which enables the transformation of the image data from RGB to HSV color space and calculation of a mean value of the light-intensity component (V).

Enhanced and Heteromolecular Guest Encapsulation in Nonporous Crystals of a Perfluorinated Triketonato Dinuclear Copper Complex.

The flexible host framework of a perfluorinated mononuclear copper complex, [Cu(L ) ] (1, HL =3-hydroxy-1,3-bis(pentafluorophenyl)-2-propen-1-one), with a CuO core reversibly encapsulated several organic guest molecules through electrostatic interactions in its crystals. Hence, the corresponding dinuclear complex, [Cu (L ) ] (2, H L =1,5-dihydroxy-1,5-bis(pentafluorophenyl)-1,4-pentadien-3-one), was prepared to enhance guest recognition and the ability to separate molecular mixtures. Complex 2 comprises a Cu O core and four pentafluorophenyl groups.

Adsorption and Conformation of Bovine Serum Albumin with Blue-Emitting Gold Nanoclusters at the Air/Water and Lipid/Water Interfaces.

Protein-encapsulated nanoclusters (NCs) are emerging as a versatile platform for in-vivo imaging and other biomedical applications due to their ultrasmall size and excitation in the near-infrared region. Encapsulation may however affect protein structure, size, charge, and its interaction with lipid membranes. In this study, bulk characterization methods along with surface-sensitive vibrational sum-frequency generation (VSFG) spectroscopy were employed to study the secondary structure of bovine serum albumin (BSA) with blue-emitting AuNCs at the air/water and 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG) lipid/water interfaces.

Impact of Support (MCF, ZrO, ZSM-5) on the Efficiency of Ni Catalyst in High-Temperature Conversion of Lignocellulosic Biomass to Hydrogen-Rich Gas.

The main objective of this work was to evaluate an impact of a support on the efficiency of nickel catalysts in the high-temperature conversion of lignocellulosic biomass to hydrogen-rich gas. The most important parameters influencing catalytic performance of the catalysts were identified. The properties of three materials (ZSM-5, ZrO, and MCF (mesostructured cellular foam)) used as a support differing in surface acidity, surface area, pore structure, ability to interact with an active phase, and resistance to coking, have been studied.

Guest encapsulations in non-porous crystals of fully fluorinated dinuclear metal complexes with the MO core (M = Fe, Co, Ni).

Two different coordination types of fully fluorinated dinuclear metal complexes, [Fe2L4(OMe)2] and [M2L4(OH2)2] (M = Co2+, Ni2+ and HL = bis(pentafluorobenzoyl)methane), were obtained. All of the complexes form non-porous crystals, which act as hosts for the adsorption of various benzene derivatives, e.g.

Duramycin-induced destabilization of a phosphatidylethanolamine monolayer at the air-water interface observed by vibrational sum-frequency generation spectroscopy.

Duramycin is a small tetracyclic peptide which binds specifically to ethanolamine phospholipids (PE). In this study, we used lipid monolayers consisting of 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) and various phosphatidylcholines (PC) to investigate the effect of duramycin on the organization of lipids and its influence on surrounding water molecules, using vibrational sum-frequency generation spectroscopy in conjunction with surface pressure measurements and fluorescence microscopy. The results show that while duramycin has no effect on the PC lipid monolayers, it induces significant disorder of PE molecules and causes an increase of the PE monolayer surface pressure.

Nondissociative chemisorption of short chain alkanethiols on Au(111).

The adsorption of methanethiol and n-propanethiol on the Au(111) surface has been studied by temperature-programmed desorption (TPD), Auger electron spectroscopy (AES), and low-temperature scanning tunneling microscopy (LT-STM). Methanethiol desorbs molecularly from the chemisorbed monolayer at temperatures below 220 K in three overlapping desorption processes. No evidence for S-H or C-S bond cleavage has been found on the basis of three types of observations: (1) A mixture of chemisorbed CH3SD and CD3SH does not yield CD3SD, (2) no sulfur remains after desorption, and (3) no residual surface species remain when the adsorbed layer is heated to 300 K as measured by STM.

Spatial distributions of desorbing products in basic catalytic processes and surface nano-structures.

Reviews of recent progress in angle-resolved measurements of desorbing surface reaction products are discussed. The angular and velocity distributions of desorbing products deliver information about the reaction site as well as the reaction mechanism when the products are repulsively desorbed. These distribution measurements can yield symmetry and orientation information of the reaction site for associative processes whereas, in dissociative desorption, the collimation of fragment desorption is related to the orientation of the intermediate species immediately before dissociation.