Flame-heated tubes are widespread in flame-AAS, mainly for the determination of hydride-forming elements. Instead of the introduction of gaseous compounds liquids can also be introduced continuously in such an absorption cell. With the aid of an HPLC pump the liquid is forced through a very fine nozzle, generating an aerosol beam less than 0.5 mm in diameter. This beam travels a distance of 10cm as a "free-flying aerosol jet" into the sample introduction hole of a metal tube furnace placed in the flame. Both introduction of the entire sample and the long residence time lead to a considerable improvement in power of detection. The detection limit for 100 microL samples amounts to 7 microg/L (Pb) and to 0.2 microg/L (Cd), which means an increase in power of detection of between one and two orders of magnitude compared to conventional flame-AAS. The relative standard deviation (100 microL sample volume, N = 10) was found to be 1.3% (signal area) for 600 microg/L Pb and to be 1.5% (signal-area) for 15 microg/L Cd. RSD values from measurements in peak-height amounted to 2.2% (Pb) and to 1.7% (Cd).
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http://dx.doi.org/10.1007/s002160000567 | DOI Listing |
Front Chem
January 2025
Center for Advanced Laser Technology, Hebei University of Technology, Tianjin, China.
Gas sensors are now widely employed in many industries due to the rapid speed of industrialization and the growth of the Internet of Things. However, the wearability and mobility of traditional gas sensors are limited by their high reliance on external power sources. Nanogenerators (NGs) can compensate for their power source limitations when paired with gas sensors by transforming the environment's widely dispersed low-frequency energy into electrical energy, allowing for self-powered gas detection.
View Article and Find Full Text PDFThe competition for resources is a defining feature of microbial communities. In many contexts, from soils to host-associated communities, highly diverse microbes are organized into metabolic groups or guilds with similar resource preferences. The resource preferences of individual taxa that give rise to these guilds are critical for understanding fluxes of resources through the community and the structure of diversity in the system.
View Article and Find Full Text PDFNeurophotonics
January 2025
California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States.
Significance: Cerebral blood flow (CBF) and cerebral blood volume (CBV) are key metrics for regional cerebrovascular monitoring. Simultaneous, non-invasive measurement of CBF and CBV at different brain locations would advance cerebrovascular monitoring and pave the way for brain injury detection as current brain injury diagnostic methods are often constrained by high costs, limited sensitivity, and reliance on subjective symptom reporting.
Aim: We aim to develop a multi-channel non-invasive optical system for measuring CBF and CBV at different regions of the brain simultaneously with a cost-effective, reliable, and scalable system capable of detecting potential differences in CBF and CBV across different regions of the brain.
Int J Nurs Stud Adv
June 2025
Centre of Excellence in Early Intervention and Family Studies, Department of Psychology, University of Copenhagen, Denmark.
Background: Screening for perinatal depression using the Edinburgh Postnatal Depression Scale (EPDS) improves detection and increases health service utilization. However, previous studies with antenatal samples indicate that positive screenings might reflect transient distress that resolves without intervention, raising concerns about over-pathologizing typical postnatal responses and inefficiencies in referral practices. Therefore, distinguishing between transient and enduring depressive symptoms for appropriate referrals to secondary services is crucial, highlighting the need for a refined screening practice.
View Article and Find Full Text PDFFront Med Technol
January 2025
Ph.D. in Health Science Program, Faculty of Medicine, Mahasarakham University, Mahasarakham, Thailand.
Background: The aging population is increasingly affected by periodontal disease, a condition often overlooked due to its asymptomatic nature. Despite its silent onset, periodontitis is linked to various systemic conditions, contributing to severe complications and a reduced quality of life. With over a billion people globally affected, periodontal diseases present a significant public health challenge.
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