Today, labs that carry out chemical analyses for regulation, food safety, health, forensics, or even security purposes are looking for ways to accelerate the analytical process. Slow procedures are costly because the necessary instruments are expensive and require maintenance and a highly trained staff to operate them. One of the more ubiquitous instruments in such labs is a Gas Chromatograph (GC), which accepts a solution and outputs each of the compounds within it in a gaseous form, one by one to be further analyzed and identified, usually by a Mass Spectrometer (MS). This separation process in a GC can be rather time-consuming, partly due to the slow heating and cooling of the GC column through which the compounds move, which happens inside a box-shaped oven. This paper describes a controller developed for a unique Open Probe Fast GC instrument that enables, among other things, high-speed and controlled heating and cooling of a gas-carrying capillary transfer line. Fast heating is achieved by precisely controlling the electrical current flowing through the small inner-diameter steel tube through which the GC column passes. The fast cooling occurs by exposing the low-mass heated tube to room temperature, along with the assistance of a simple fan that carries the heated air away. This technology also supports control of other system parts, including a unique quick sampling device called an Open Probe that allows for an even faster analysis cycle. Our design is based entirely on a digital signal processor (DSP) and digital control. The use of pulse width modulation (PWM) control enables a compact and efficient system.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.chroma.2021.462576 | DOI Listing |
Nanomaterials (Basel)
December 2024
Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Poland.
A Scanning Photoelectron Microscopy (SPEM) experiment has been applied to ZnO:N films deposited by Atomic Layer Deposition (ALD) under O-rich conditions and post-growth annealed in oxygen at 800 °C. spatial resolution (130 nm) allows for probing the electronic structure of single column of growth. The samples were cleaved under ultra-high vacuum (UHV) conditions to open atomically clean cross-sectional areas for SPEM experiment.
View Article and Find Full Text PDFWest J Nurs Res
January 2025
Golden Apple Healing Arts, LLC, Wauwatosa, WI, USA.
Background: The concept of inclusion within diversity, equity, and inclusion has broad meanings and implications and has not been explored in nursing through a World Café.
Purpose: To describe the process and experiences of 9 nurse scientists who hosted a World Café focused on inclusion, to share participants' insights, and to offer considerations to advance inclusion in nursing.
Approach: We hosted and encouraged active participation in a World Café that focused on 7 inclusion topics in nursing during the 2024 Midwestern Nursing Research Society Annual Research Conference.
Alzheimers Dement
December 2024
Universidad de La Laguna, Santa Cruz de Tenerife, Spain.
Background: The brain undergoes structural changes during aging, such as gray matter loss, enlarged ventricles, and sulcal widening. However, previous studies have primarily investigated these changes in isolation, without describing the complex spatial relationships between overall brain shape and regions. Here, we tested how gradients of expansion and compression of the global shape of the brain as well as between homologous brain regions across hemispheres are affected by age, and whether these changes further contribute to clinical impairment and cognitive deficits in older adults.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
University of Puerto Rico, Medical Sciences Campus, School of Medicine, San Juan, PR, USA.
Background: Alzheimer's disease (AD) is a neurodegenerative condition characterized by a gradual decline in mental function, progressing to death. Evidence suggests the apolipoprotein E (ApoE) gene influences Alzheimer's risk. Allele E2 is neuroprotective, E3 is neutral, and E4 is associated with a higher genetic risk for AD.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
University of Illinois College of Medicine at Peoria, Peoria, IL, USA.
Background: Many lines of evidence support that systemic inflammation promotes Alzheimer's disease (AD) progression. Amyloid plaques are closely accompanied with neuroinflammation characterized by activated microglia and reactive astrocytes. Aging is the largest known risk factor for AD and is characterized by chronic, systemic, low-grade inflammation (inflamm-aging).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!