On-chip mid-infrared optical sensing with GeSbSe waveguides and resonators.

We fabricated single mode GeSbSe waveguides and resonators using e-beam lithography and achieved a propagation loss of 3.88 dB/cm at 3.66 µm.

Fabrication and characterization of high quality GeSbSe reflowed and etched ring resonators.

We demonstrate the fabrication of high Q GeSbSe ring resonators in an all chalcogenide platform through electron-beam lithography, lift-off and thermal reflow. We achieve a Q factor of (3.9 ± 0.

Adaptive immunity to human coronaviruses is widespread but low in magnitude.

Objectives: Endemic human coronaviruses (hCoVs) circulate worldwide but cause minimal mortality. Although seroconversion to hCoV is near ubiquitous during childhood, little is known about hCoV-specific T-cell memory in adults.

Methods: We quantified CD4 T-cell and antibody responses to hCoV spike antigens in 42 SARS-CoV-2-uninfected individuals.

Third-harmonic generation enhancement in an ITO nanoparticle-coated microresonator.

We report a ∼3-fold enhancement of third-harmonic generation (THG) conversion efficiency using indium tin oxide (ITO) nanoparticles on the surface of an ultra-high-Q silica microsphere. This is one of the largest microcavity-based THG enhancements reported. Phase-matching and spatial mode overlap are explored numerically to determine the microsphere radius (∼29 µm) and resonant mode numbers that maximize THG.

Enhancement of third-order nonlinearity of thermally evaporated GeSbSe waveguides through annealing.

Chalcogenides are a promising platform for infrared nonlinear optics but are susceptible to structural changes during fabrication that affect their linear and nonlinear optical properties. We analyze the structure and optical properties of thermally evaporated and annealed chalcogenide films. Thermally evaporated GeSbSe has an increased selenium content, bandgap, and concentration of heteropolar bonds.

Mass spectral studies of the biologically active stereoisomer family of -(methanofullrene(60-63)-carboxylic acids.

Fullerene-based compounds are being developed for an extensive range of biomedical applications, and may provide a completely new class of biologically useful reagents. In support of our continuing investigation and characterization of one such compound, -fullerene(60)-63-tris malonic acid () we optimized the conditions for obtaining mass spectra. Both positive and negative ion mass spectra are obtained using electrospray ionization (ESI).

High quality chalcogenide-silica hybrid wedge resonator.

Chalcogenide glasses, with high nonlinearity and low loss, have captured research interest as an integrated device platform for near- and mid-infrared nonlinear optical devices. Compared to silicon-based microfabrication technologies, chalcogenide fabrication processes are less mature and a major challenge is obtaining high quality devices. In this paper, we report a hybrid resonator design leveraging a high quality silica resonator to achieve high Q factors with chalcogenide.

Back to basics: hand hygiene and isolation.

Purpose Of Review: Hand hygiene and isolation are basic, but very effective, means of preventing the spread of pathogens in healthcare. Although the principle may be straightforward, this review highlights some of the controversies regarding the implementation and efficacy of these interventions.

Recent Findings: Hand hygiene compliance is an accepted measure of quality and safety in many countries.

The incidence of HBV and HCV infection in Australian travelers to Asia.

We analyzed paired pre- and post-travel sera in a cohort of Australian travelers to Asia and demonstrated the acquisition of hepatitis C virus (HCV) and hepatitis B virus (HBV) infection. The incidence density in nonimmune travelers for HCV infection was calculated as 1.8 infections per 10,000 traveler-days and for HBV infection 2.

John Bennett Fenn: a curious road to the prize.

John Bennett Fenn shared the 2002 Nobel Prize in Chemistry for his development of electrospray ionization (ESI). There are several excellent, in-depth biographical reviews of Fenn's scientific career Fenn (Angew. Chem.

The identification of synthetic homopolymer end groups and verification of their transformations using MALDI-TOF mass spectrometry.

Recent advances in the resolving power of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) enable the detailed characterization of linear homopolymers, and in particular provide invaluable data for the determination of their end-group functionalities. With the growing importance of macromolecular coupling reactions in building complex polymer architectures, the ability to accurately monitor end-group transformations is becoming increasingly important for synthetic polymer chemists. This tutorial demonstrates the application of MALDI-TOF MS in determining both end-group functionalities and their transformations for linear homopolymers.

Use of the "RAM" susceptibility testing method for rapid detection of clarithromycin resistance in the Mycobacterium avium complex.

Standard susceptibility testing of the Mycobacterium avium complex (MAC) can require 7 to 14 days from initial isolation. We evaluated a high-performance liquid chromatography-based susceptibility test for rapid determination of clarithromycin (CLR) resistance in MAC. This method can be completed in 72 h of incubation.

Application of SIMSTEX to oligomerization of insulin analogs and mutants.

The propensity of various insulins and their analogs to oligomerize was investigated by mass spectrometric methods including measurement of the relative abundances of oligomers in the gas phase and the kinetics of H/D amide exchange. The kinetics of deuterium uptake show a good fit when the exchanging amides are placed in three kinetic groups: fast, intermediate, and slow. r-Human insulin, of the insulins investigated, has fewer amides that exchange at intermediate rates and more that exchange at slow rates, in accord with its higher extent of association in solution.

Ion-exchange chromatography followed by ESI-MS for quantitative analysis of sugar monophosphates from glucose catabolism.

The aim of this work is to establish a quantitative method to determine the ratio of [U-(13)C] labeled to unlabeled hexose monophosphates isolated from yeast extracts. This is accomplished by anion exchange chromatography and mobile phase desalting followed by electrospray (ESI) mass spectrometry. We test the method with the analysis of a sample of biological origin.