Quantification and visulization of taurine delivery and penetration into skin

Taurine is used in many personal care products to help deliver skin repair and anti-irritation benefits. Enhancing the deposition and penetration of taurine in skin is likely to boost the performance of these products. In this study, we demonstrated the deposition of taurine onto skin surfaces through a serum formulation, as well as enhanced penetration of taurine into deeper skin layers, aided by permeation enhancers such as glycerin and dimethyl isosorbide. We used a tape stripping method to collect samples from porcine skin and, coupled with HPLC analysis, to quantify the deposition and penetration of taurine. Serum formulations containing different levels of the permeation enhancers were tested. Glycerin and dimethyl isosorbide were found particularly effective and showed a dose-response manner to enhance the taurine penetration. We also employed two spectroscopic techniques, ATR-FTIR and confocal Raman to visualize the taurine distribution in the skin. The hyperspectral images of both IR and Raman clearly demonstrated the increased penetration of taurine into the deeper layers of the skin, beyond stratum corneum and into the epidermis, through the use of these permeation enhancers. These observations are consistent with the results from the tape stripping-HPLC analyses

High temperature reactions between Si3N4 bonded SiC materials and Cu, Cu2O and matte

Si3N4 bonded SiC (Si3N4-SiC) is a conventional refractory material and has broad applications. In the present study, Si3N4-SiC refractory materials were systematically investigated in the copper-making environment. Si3N4SiC was reacted with Cu, Cu2O, industrial matte, Cu2S and FeS melts at 1200 degrees C in argon gas atmosphere, and all samples were directly quenched in water after the experiments. Phase changes and compositions of the phases were measured by electron probe X-ray microanalysis. The present investigations demonstrate that Cu and Cu2S do not react with Si3N4-SiC at high temperatures and the wettability between this material and the melts is low. However, significant reactions occur between Si3N4-SiC and Cu2O, industrial matte and FeS. The results imply that Si3N4-SiC material has limited oxidation-resistance and can only be used under reducing conditions

Growth of carbon nanowalls at atmospheric pressure for one-step gas sensor fabrication

Carbon nanowalls (CNWs), two-dimensional "graphitic" platelets that are typically oriented vertically on a substrate, can exhibit similar properties as graphene. Growth of CNWs reported to date was exclusively carried out at a low pressure. Here, we report on the synthesis of CNWs at atmosphere pressure using "direct current plasma-enhanced chemical vapor deposition" by taking advantage of the high electric field generated in a pin-plate dc glow discharge. CNWs were grown on silicon, stainless steel, and copper substrates without deliberate introduction of catalysts. The as-grown CNW material was mainly mono- and few-layer graphene having patches of O-containing functional groups. However, Raman and X-ray photoelectron spectroscopies confirmed that most of the oxygen groups could be removed by thermal annealing. A gas-sensing device based on such CNWs was fabricated on metal electrodes through direct growth. The sensor responded to relatively low concentrations of NO2 (g) and NH3 (g), thus suggesting high-quality CNWs that are useful for room temperature gas sensors

Systematic benchmarking of nanopore Q20+ kit in SARS-CoV-2 whole genome sequencing

Whole genome sequencing provides rapid insight into key information about the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), such as virus typing and key mutation site, and this information is important for precise prevention, control and tracing of coronavirus disease 2019 (COVID-19) outbreak in conjunction with the epidemiological information of the case. Nanopore sequencing is widely used around the world for its short sample-to-result time, simple experimental operation and long sequencing reads. However, because nanopore sequencing is a relatively new sequencing technology, many researchers still have doubts about its accuracy. The combination of the newly launched nanopore sequencing Q20+ kit (LSK112) and flow cell R10.4 is a qualitative improvement over the accuracy of the previous kits. In this study, we firstly used LSK112 kit with flow cell R10.4 to sequence the SARS-CoV-2 whole genome, and summarized the sequencing results of the combination of LSK112 kit and flow cell R10.4 for the 1200bp amplicons of SARS-CoV-2. We found that the proportion of sequences with an accuracy of more than 99% reached 30.1%, and the average sequence accuracy reached 98.34%, while the results of the original combination of LSK109 kit and flow cell R9.4.1 were 0.61% and 96.52%, respectively. The mutation site analysis showed that it was completely consistent with the final consensus sequence of next generation sequencing (NGS). The results showed that the combination of LSK112 kit and flow cell R10.4 allowed rapid whole-genome sequencing of SARS-CoV-2 without the need for verification of NGS

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

NMR, Crystallographic and Quantum Chemical Studies of Metalloproteins and Bisphosphonate Inhibitors

180 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2004.In this work, we describe the development of computational models to predict nuclear magnetic resonance (NMR) and Mossbauer spectroscopic properties in heme proteins and model systems by using quantum chemical techniques. This work includes density functional theory investigations of the 1H, 13C, 15N and 19F NMR hyperfine shifts, Mossbauer electric field gradient tensors (quadrupole splittings and asymmetry parameters) and their orientations, Mossbauer isomer shifts, and through space J-couplings. Excellent correlations between experiment and theory indicate that the computed wavefunctions are of high quality and molecular orbital analyses provide a graphical representation of the spin density distributions. These powerful new probes are then used in local structure (ligand-binding geometry) refinement and prediction. In part two of this thesis, we describe structural investigations of bisphosphonate drugs and their target enzyme, farnesyl diphosphate synthase (FPPS), using NMR, crystallography and computational techniques. The X-ray structures of nine bisphosphonates are reported together with their 31P solid-state NMR chemical shifts and anisotropic shift (or shielding) tensors, which are highly correlated with the quantum mechanical predictions. Some of these X-ray structures are also used in three-dimensional quantitative structure-activity relationship studies of the bisphosphonate inhibition of Leishmania major FPPS. The FPPS from Trypanosoma brucei (the causative agent of African sleeping sickness) is expressed in E. coli and purified for crystallographic studies. Single crystals of both drug-free and drug-bound FPPSs are obtained and diffract to 3.3 A and 2.5 A, respectively, using synchrotron radiation. A preliminary model of the drug-free enzyme is built using a homology model and the molecular replacement method. Static and electronic structures of bisphosphonates, as well as X-ray structures of FPPS, will further our understanding of FPPS inhibition, allowing for the structure-based design of novel chemotherapeutic agents.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

NMR, Crystallographic and Quantum Chemical Studies of Metalloproteins and Bisphosphonate Inhibitors

180 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2004.In this work, we describe the development of computational models to predict nuclear magnetic resonance (NMR) and Mossbauer spectroscopic properties in heme proteins and model systems by using quantum chemical techniques. This work includes density functional theory investigations of the 1H, 13C, 15N and 19F NMR hyperfine shifts, Mossbauer electric field gradient tensors (quadrupole splittings and asymmetry parameters) and their orientations, Mossbauer isomer shifts, and through space J-couplings. Excellent correlations between experiment and theory indicate that the computed wavefunctions are of high quality and molecular orbital analyses provide a graphical representation of the spin density distributions. These powerful new probes are then used in local structure (ligand-binding geometry) refinement and prediction. In part two of this thesis, we describe structural investigations of bisphosphonate drugs and their target enzyme, farnesyl diphosphate synthase (FPPS), using NMR, crystallography and computational techniques. The X-ray structures of nine bisphosphonates are reported together with their 31P solid-state NMR chemical shifts and anisotropic shift (or shielding) tensors, which are highly correlated with the quantum mechanical predictions. Some of these X-ray structures are also used in three-dimensional quantitative structure-activity relationship studies of the bisphosphonate inhibition of Leishmania major FPPS. The FPPS from Trypanosoma brucei (the causative agent of African sleeping sickness) is expressed in E. coli and purified for crystallographic studies. Single crystals of both drug-free and drug-bound FPPSs are obtained and diffract to 3.3 A and 2.5 A, respectively, using synchrotron radiation. A preliminary model of the drug-free enzyme is built using a homology model and the molecular replacement method. Static and electronic structures of bisphosphonates, as well as X-ray structures of FPPS, will further our understanding of FPPS inhibition, allowing for the structure-based design of novel chemotherapeutic agents.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Protein Viability on Au Nanoparticles during an Electrospray and Electrostatic-Force-Directed Assembly Process

We study the protein viability on Au nanoparticles during an electrospray and electrostatic-force-directed assembly process, through which Au nanoparticle-antibody conjugates are assembled onto the surface of carbon nanotubes (CNTs) to fabricate carbon nanotube field-effect transistor (CNTFET) biosensors. Enzyme-linked immunosorbent assay (ELISA) and field-effect transistor (FET) measurements have been used to investigate the antibody activity after the nanoparticle assembly. Upon the introduction of matching antigens, the colored reaction from the ELISA and the change in the electrical characteristic of the CNTFET device confirm that the antibody activity is preserved during the assembly process