In comprehensive two-dimensional gas chromatography (GC x GC), a modulator is placed at the juncture between two separation columns to focus and re-inject eluting mixture components, thereby enhancing the resolution and the selectivity of analytes. As part of an effort to develop a microGC x microGC prototype, in this report we present the design, fabrication, thermal operation, and initial testing of a two-stage microscale thermal modulator (microTM). The microTM contains two sequential serpentine Pyrex-on-Si microchannels (stages) that cryogenically trap analytes eluting from the first-dimension column and thermally inject them into the second-dimension column in a rapid, programmable manner. For each modulation cycle (typically 5 s for cooling with refrigeration work of 200 J and 100 ms for heating at 10 W), the microTM is kept approximately at -50 degrees C by a solid-state thermoelectric cooling unit placed within a few tens of micrometres of the device, and heated to 250 degrees C at 2800 degrees C s(-1) by integrated resistive microheaters and then cooled back to -50 degrees C at 250 degrees C s(-1). Thermal crosstalk between the two stages is less than 9%. A lumped heat transfer model is used to analyze the device design with respect to the rates of heating and cooling, power dissipation, and inter-stage thermal crosstalk as a function of Pyrex-membrane thickness, air-gap depth, and stage separation distance. Experimental results are in agreement with trends predicted by the model. Preliminary tests using a conventional capillary column interfaced to the microTM demonstrate the capability for enhanced sensitivity and resolution as well as the modulation of a mixture of alkanes.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1039/c001390k | DOI Listing |
Geroscience
January 2025
National Institute On Aging, Bethesda, MD, USA.
Photobiomodulation (PBM) therapy, a non-thermal light therapy using nonionizing light sources, has shown therapeutic potential across diverse biological processes, including aging and age-associated diseases. In 2023, scientists from the National Institute on Aging (NIA) Intramural and Extramural programs convened a workshop on the topic of PBM to discuss various proposed mechanisms of PBM action, including the stimulation of mitochondrial cytochrome C oxidase, modulation of cell membrane transporters and receptors, and the activation of transforming growth factor-β1. They also reviewed potential therapeutic applications of PBM across a range of conditions, including cardiovascular disease, retinal disease, Parkinson's disease, and cognitive impairment.
View Article and Find Full Text PDFBMC Microbiol
January 2025
Chair of Microbiology, Jagiellonian University Medical College in Krakow, 18 Czysta Street, Cracow, 31-121, Poland.
Background: Aerobic vaginitis (AV) is a state of abnormal vaginal microbiota, which is associated with increased numbers of aerobic, enteric bacteria and inflammation of the vaginal epithelium. Anti-microbial treatment combined with anti-inflammatory therapy could be useful in the treatment of this condition. It is known that calcitriol, the active form of vitamin D, plays an important role in modulating the immune response in several inflammatory diseases.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, United States.
Gut dysbiosis contributes to multiple pathologies, yet the mechanisms of the gut microbiota-mediated influence on systemic and distant responses remain largely elusive. This study aimed to identify the role of nanosized bacterial extracellular vesicles (bEVs) in mediating allodynia, i.e.
View Article and Find Full Text PDFBiomed Pharmacother
January 2025
Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Neurochemistry, 12 Smetna Str., Krakow 31-343, Poland. Electronic address:
Neuropathic pain is a disorder affecting the somatosensory nervous system. However, this condition is also characterized by significant neuroinflammation, primarily involving CNS-resident non-neuronal cells. A promising target for developing new analgesics is histamine H receptor (HR); thus, we aimed to determine the influence of a novel HR antagonist/inverse agonist, E-98 (1-(7-(4-chlorophenoxy)heptyl)-3-methylpiperidine), on pain symptoms and glia activation in model of neuropathic pain in male mice (chronic constriction injury to the sciatic nerve).
View Article and Find Full Text PDFEur J Med Chem
January 2025
Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, SE, 17165, Sweden; Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, SE1 9RT, UK. Electronic address:
Clear cell renal cell carcinoma (ccRCC) presents substantial therapeutic challenges due to its molecular heterogeneity, limited response to conventional therapies, and widespread drug resistance. Recent advancements in molecular research have identified novel targets, such as BUB1B, which has been identified through global transcriptomic profiling and gene co-expression network analysis as critical in ccRCC progression. In this study, we synthesized 40 novel derivatives of TG-101209 to modulate BUB1B expression and activity, leading to the induction of apoptosis in Caki-1 cells.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!