scholarly journals Performance evaluation of in situ fluorometers for real-time cyanobacterial monitoring

2018 ◽  
Vol 1 (1) ◽  
pp. 26-46 ◽  
Author(s):  
Florence Choo ◽  
Arash Zamyadi ◽  
Kelly Newton ◽  
Gayle Newcombe ◽  
Lee Bowling ◽  
...  
Keyword(s):  
Real Time ◽  
Green Algae ◽  
High Water ◽  
P Value ◽  
Water Quality Standards ◽  
Robust Performance ◽  
Cyanobacterial Species ◽  
Cellular Suspension ◽  
The Impact

Abstract Detecting the presence of cyanobacteria is an integral part of maintaining high water quality standards. In situ fluorometers are tools which may allow for the detection of cyanobacteria in real-time but there are few studies that review fluorometer performance. A systematic study that evaluated the performance of a range of fluorometers using key cyanobacterial species of interest and two known sources of interference (green algae and added turbidity) was undertaken. Specifically, six fluorometers and four cyanobacterial species were investigated. A good correlation (R2 ≥ 0.92 and p-value of <0.001) was obtained for mono cell culture suspensions, with robust performance exhibited for all fluorometers. Limits of detection for the fluorometers and multiplier factors which enable direct comparison of fluorometers were developed. The addition of green algae caused fluorometer performance to decrease by either overestimating or underestimating the concentration of cyanobacteria in a cellular suspension. Some fluorometers were more susceptible to these interference sources; the magnitude of the fluorometer measurement inaccuracy was dependent on cyanobacteria concentration and interference source. This study indicates that while there are inherent problems with fluorometers, the extent of the impact from interference sources can be characterised and potentially corrected to enable successful cyanobacteria detection in the field.

scholarly journals Tracking Metamorphic Dehydration Reactions in Real Time with Transmission Small- and Wide-Angle Synchrotron X-ray Scattering: the Case of Gypsum Dehydration

2020 ◽  
Vol 61 (6) ◽  
Author(s):  
C E Schrank ◽  
K Gioseffi ◽  
T Blach ◽  
O Gaede ◽  
A Hawley ◽  
...  
Keyword(s):  
Real Time ◽  
Wide Angle ◽  
Length Scales ◽  
X Ray ◽  
Rock Samples ◽  
X Ray Scattering ◽  
Dehydration Reactions ◽  
The Impact ◽  
Ray Scattering

Abstract We present a review of a unique non-destructive method for the real-time monitoring of phase transformations and nano-pore evolution in dehydrating rocks: transmission small- and wide-angle synchrotron X-ray scattering (SAXS/WAXS). It is shown how SAXS/WAXS can be applied to investigating rock samples dehydrated in a purpose-built loading cell that allows the coeval application of high temperature, axial confinement, and fluid pressure or flow to the specimen. Because synchrotron sources deliver extremely bright monochromatic X-rays across a wide energy spectrum, they enable the in situ examination of confined rock samples with thicknesses of ≤ 1 mm at a time resolution of order seconds. Hence, fast kinetics with reaction completion times of about hundreds of seconds can be tracked. With beam sizes of order tens to hundreds of micrometres, it is possible to monitor multiple interrogation points in a sample with a lateral extent of a few centimetres, thus resolving potential lateral spatial effects during dehydration and enlarging sample statistics significantly. Therefore, the SAXS/WAXS method offers the opportunity to acquire data on a striking range of length scales: for rock samples with thicknesses of ≤ 10-3 m and widths of 10-2 m, a lateral interrogation-point spacing of ≥ 10-5 m can be achieved. Within each irradiated interrogation-point volume, information concerning pores with sizes between 10-9 and 10-7 m and the crystal lattice on the scale of 10-10 m is acquired in real time. This article presents a summary of the physical principles underpinning transmission X-ray scattering with the aim of providing a guide for the design and interpretation of time-resolved SAXS/WAXS experiments. It is elucidated (1) when and how SAXS data can be used to analyse total porosity, internal surface area, and pore-size distributions in rocks on length scales from ∼1 to 300 nm; (2) how WAXS can be employed to track lattice transformations in situ; and (3) which limitations and complicating factors should be considered during experimental design, data analysis, and interpretation. To illustrate the key capabilities of the SAXS/WAXS method, we present a series of dehydration experiments on a well-studied natural gypsum rock: Volterra alabaster. Our results demonstrate that SAXS/WAXS is excellently suited for the in situ tracking of dehydration kinetics and the associated evolution of nano-pores. The phase transformation from gypsum to bassanite is correlated directly with nano-void growth on length scales between 1 and 11 nm for the first time. A comparison of the SAXS/WAXS kinetic results with literature data emphasises the need for future dehydration experiments on rock specimens because of the impact of rock fabric and the generally heterogeneous and transient nature of dehydration reactions in nature. It is anticipated that the SAXS/WAXS method combined with in situ loading cells will constitute an invaluable tool in the ongoing quest for understanding dehydration and other mineral replacement reactions in rocks quantitatively.

scholarly journals The Coastal Observing System for Northern and Arctic Seas (COSYNA)

Ocean Science ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 379-410 ◽  
Author(s):  
Burkard Baschek ◽  
Friedhelm Schroeder ◽  
Holger Brix ◽  
Rolf Riethmüller ◽  
Thomas H. Badewien ◽  
...  
Keyword(s):  
Real Time ◽  
The Arctic ◽  
Arctic Seas ◽  
The Public ◽  
The North ◽  
Data Products ◽  
The North Sea ◽  
Arctic Coast ◽  
The Impact

Abstract. The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example of a heavily used coastal area, and Svalbard as an example of an Arctic coast that is under strong pressure due to global change.The COSYNA automated observing and modelling system is designed to monitor real-time conditions and provide short-term forecasts, data, and data products to help assess the impact of anthropogenically induced change. Observations are carried out by combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publicly available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public.

scholarly journals The Mbam drainage system and onchocerciasis transmission post ivermectin mass drug administration (MDA) campaign, Cameroon

2021 ◽  
Vol 15 (1) ◽  
pp. e0008926
Author(s):  
Raphael Awah Abong ◽  
Glory Ngongeh Amambo ◽  
Ali Ahamat Hamid ◽  
Belinda Agbor Enow ◽  
Amuam Andrew Beng ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Large Scale ◽  
Water Discharge ◽  
Drainage System ◽  
River System ◽  
High Water ◽  
Diagnostic Techniques ◽  
Dry Seasons ◽  
The Impact

Background The impact of large scale Mass Drug Adminstration (MDA) of ivermectin on active onchocerciasis transmission by Simulium damnosum, which transmits the parasite O. volvulus is of great importance for onchocerciasis control programmes. We investigated in the Mbam river system area, the impact of MDA of ivermectin on entomological indices and also verify if there are river system factors that could have favoured the transmission of onchocerciasis in this area and contribute to the persistence of disease. We compared three independent techniques to detect Onchocerca larvae in blackflies and also analyzed the river system within 9 months post-MDA of ivermectin. Method Simulium flies were captured before and after 1, 3, 6 and 9months of ivermectin-MDA. The biting rate was determined and 41% of the flies dissected while the rest were grouped into pools of 100 flies for DNA extraction. The extracted DNA was then subjected to O-150 LAMP and real-time PCR for the detection of infection by Onchocerca species using pool screening. The river system was analysed and the water discharge compared between rainy and dry seasons. Principal findings We used human landing collection method (previously called human bait) to collect 22,274 adult female Simulium flies from Mbam River System. Of this number, 9,134 were dissected while 129 pools constituted for molecular screening. Overall biting and parous rates of 1113 flies/man/day and 24.7%, respectively, were observed. All diagnostic techniques detected similar rates of O. volvulus infection (P = 0.9252) and infectivity (P = 0.4825) at all monitoring time points. Onchocerca ochengi larvae were only detected in 2 of the 129 pools. Analysis of the river drainage revealed two hydroelectric dams constructed on the tributaries of the Mbam river were the key contributing factor to the high-water discharge during both rainy and dry seasons. Conclusion Results from fly dissection (Microscopy), real-time PCR and LAMP revealed the same trends pre- and post-MDA. The infection rate with animal Onchocerca sp was exceptionally low. The dense river system generate important breeding sites that govern the abundance of Simulium during both dry and rainy seasons.

Comparative Study on in-situ Ellipsometric Monitoring of III-Nitride Film Growth via Plasma-Enhanced Atomic Layer Deposition

2019 ◽  
Vol 28 (03n04) ◽  
pp. 1940020
Author(s):  
Adnan Mohammad ◽  
Deepa Shukla ◽  
Saidjafarzoda Ilhom ◽  
Brian Willis ◽  
Ali Kemal Okyay ◽  
...  
Keyword(s):  
Growth Rate ◽  
Real Time ◽  
Film Growth ◽  
Atomic Layer ◽  
Layer Growth ◽  
In Situ Monitoring ◽  
Rf Plasma ◽  
Nitride Film ◽  
The Impact

In this paper a comparative in-situ ellipsometric analysis is carried out on plasma-assisted ALD-grown III-nitride (AlN, GaN, and InN) films. The precursors used are TMA, TMG, and TMI for AlN, GaN, and InN respectively, while Ar is used as purge gas. For all of the films N2/H2/Ar plasma was used as the co-reactant. The work includes real-time in-situ monitored saturation curves, unit ALD cycle analysis, and >500 cycle film growth runs. In addition, the films are grown at different substrate temperatures to observe the impact of temperature not only on the growth rate but on how it influenced the precursor chemisorption, ligand removal, and nitrogen incorporation surface reactions. All three nitride films confirm fairly linear growth character. The growth rate per cycle (GPC) for each film is also measured with respect to rf-plasma power to obtain the surface saturation conditions during ALD growth. The real-time in-situ monitoring of the film growth can really be beneficial to understand the atomic layer growth and film formation in each individual ALD cycle.

Abstract 19958: Evaluation of Tricuspid Regurgitation (TR) Severity Prior to and after Device Extraction in Patients with Cardiac Device Infection

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Thomas Butler ◽  
Akhlaq Khan ◽  
Abhishek Sengupta ◽  
Jonathan Sherman ◽  
Russell Denman ◽  
...  
Keyword(s):  
Risk Factors ◽  
Tricuspid Regurgitation ◽  
P Value ◽  
Cardiac Device ◽  
Clinical Complications ◽  
Device Infection ◽  
The Mean ◽  
Device Extraction ◽  
The Impact

Aim: This study sought to evaluate the impact of device extraction on the severity of TR in patients with cardiac device related infection (CDI) and infective endocarditis (CDRIE). Methods: The medical and echocardiographic records of 142 patients who had undergone device extraction for suspected infection from 2007 - 2013 were reviewed. Data on clinical complications, echocardiographic documentation of TR severity prior to and after device removal and potential risk factors for change in TR severity was obtained. A paired t test was used to evaluate whether the TR mean grade changed significantly. Patient Demographics: A total of 56 patients out of the 142 patients had TTE and/or TOE imaging. Of these patients, 22 patients had ICD’s, 27 patients had PPM’s and 7 patients had BiV Devices. The mean age was 62 years (47 males). Clinical complications included decompensated heart failure (12.5%), septic shock (8.9%), septic arthritis (8.9%), splenic abscess (1.78%), septic pulmonary embolism (5.35%), leukocytoclastic vasculitis (1.78%). Results: The mean duration of device in situ prior to extraction was 64 months (5.33yrs). The mean grade of TR prior to device extraction was grade 1.35/4 (SD=0.901, C.I. 1.16 to 1.72). The mean grade of TR post extraction was 1.54/4 (SD= 0.96 with C.I. 1.26 to 1.89). The mean difference in mean TR grade was 0.13 (C.I. 0.37 to -0.106) p >0.05. One patient had a worsening of TR by at least 2 grades post extraction. This was due to valve perforation from infection rather than extraction related trauma. This was the only patient that required surgery for clinically significant TR. Risk factors for worsening TR post extraction included the length of time leads were in situ and age of the patient. Time of Device in situ prior to extraction did not correlate significantly with severity of TR post procedure rho 0.12 (p value = 0.45). Furthermore, age at the time of the procedure did not correlate with tricuspid regurgitation severity post extraction rho 0.21 (p value = 0.18). Conclusions: Worsening of TR post extraction is uncommon and is more likely due to valve destruction from infection rather than trauma to the valve during extraction. Furthermore, a number of complications occur peri-procedurally that impacts on patient outcomes.

scholarly journals The Coastal Observing System for Northern and Arctic Seas (COSYNA)

2016 ◽  
Author(s):  
B. Baschek ◽  
F. Schroeder ◽  
H. Brix ◽  
R. Riethmüller ◽  
T. H. Badewien ◽  
...  
Keyword(s):  
Real Time ◽  
The Arctic ◽  
Arctic Seas ◽  
The Public ◽  
The North ◽  
Data Products ◽  
The North Sea ◽  
Arctic Coast ◽  
The Impact

Abstract. The Coastal Observing System for Northern and Arctic Seas (COSYNA) was established in order to better understand the complex interdisciplinary processes of northern seas and the arctic coasts in a changing environment. Particular focus is given to the German Bight in the North Sea as a prime example for a heavily used coastal area, and Svalbard as an example of an arctic coast that is under strong pressure due to global change. The automated observing and modelling system COSYNA is designed to monitor real time conditions, provide short-term forecasts and data products, and to assess the impact of anthropogenically induced change. Observations are carried out combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publically available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public.

scholarly journals Assimilating GlobColour ocean colour data into a pre-operational physical-biogeochemical model

2012 ◽  
Vol 9 (2) ◽  
pp. 687-744 ◽  
Author(s):  
D. A. Ford ◽  
K. P. Edwards ◽  
D. Lea ◽  
R. M. Barciela ◽  
M. J. Martin ◽  
...  
Keyword(s):  
Real Time ◽  
Chlorophyll Concentration ◽  
Ocean Basin ◽  
Biogeochemical Model ◽  
State Variables ◽  
Ocean Colour ◽  
In Situ Observations ◽  
Time Basis ◽  
The Impact

Abstract. As part of the GlobColour project, daily chlorophyll-a observations, derived using remotely sensed ocean colour data from the MERIS, MODIS and SeaWiFS sensors, are produced. The ability of these products to be assimilated into a pre-operational global coupled physical-biogeochemical model has been tested, on both a hindcast and near-real-time basis, and the impact on the system assessed. The assimilation was found to immediately and significantly improve the bias, root mean square error and correlation of modelled surface chlorophyll concentration compared to the GlobColour observations, an improvement which was sustained throughout the year and in every ocean basin. Errors against independent in situ chlorophyll observations were also reduced, both at and beneath the ocean surface. However the model fit to in situ observations was not consistently better than that of climatology, due to errors in the underlying model. The assimilation scheme used is multivariate, updating all biogeochemical model state variables at all depths. Consistent changes were found in the other model variables, with reduced errors against in situ observations of nitrate and pCO2, and evidence of improved representation of zooplankton concentration. Annual mean surface fields of nutrients, alkalinity and carbon variables remained of similar quality compared to climatology. The near-real-time GlobColour products were found to be sufficiently reliable for operational purposes, and of benefit to both operational-style systems and reanalyses.

scholarly journals Versatile soil gas concentration and isotope monitoring: optimization and integration of novel soil gas probes with online trace gas detection

2022 ◽  
Vol 19 (1) ◽  
pp. 165-185
Author(s):  
Juliana Gil-Loaiza ◽  
Joseph R. Roscioli ◽  
Joanne H. Shorter ◽  
Till H. M. Volkmann ◽  
Wei-Ren Ng ◽  
...  
Keyword(s):  
Real Time ◽  
Trace Gases ◽  
Soil Gas ◽  
Redox Conditions ◽  
Trace Gas ◽  
Soil System ◽  
Isotopic Signatures ◽  
Gas Measurements ◽  
The Impact

Abstract. Gas concentrations and isotopic signatures can unveil microbial metabolisms and their responses to environmental changes in soil. Currently, few methods measure in situ soil trace gases such as the products of nitrogen and carbon cycling or volatile organic compounds (VOCs) that constrain microbial biochemical processes like nitrification, methanogenesis, respiration, and microbial communication. Versatile trace gas sampling systems that integrate soil probes with sensitive trace gas analyzers could fill this gap with in situ soil gas measurements that resolve spatial (centimeters) and temporal (minutes) patterns. We developed a system that integrates new porous and hydrophobic sintered polytetrafluoroethylene (sPTFE) diffusive soil gas probes that non-disruptively collect soil gas samples with a transfer system to direct gas from multiple probes to one or more central gas analyzer(s) such as laser and mass spectrometers. Here, we demonstrate the feasibility and versatility of this automated multiprobe system for soil gas measurements of isotopic ratios of nitrous oxide (δ18O, δ15N, and the 15N site preference of N2O), methane, carbon dioxide (δ13C), and VOCs. First, we used an inert silica matrix to challenge probe measurements under controlled gas conditions. By changing and controlling system flow parameters, including the probe flow rate, we optimized recovery of representative soil gas samples while reducing sampling artifacts on subsurface concentrations. Second, we used this system to provide a real-time window into the impact of environmental manipulation of irrigation and soil redox conditions on in situ N2O and VOC concentrations. Moreover, to reveal the dynamics in the stable isotope ratios of N2O (i.e., 14N14N16O, 14N15N16O, 15N14N16O, and 14N14N18O), we developed a new high-precision laser spectrometer with a reduced sample volume demand. Our integrated system – a tunable infrared laser direct absorption spectrometry (TILDAS) in parallel with Vocus proton transfer reaction mass spectrometry (PTR-MS), in line with sPTFE soil gas probes – successfully quantified isotopic signatures for N2O, CO2, and VOCs in real time as responses to changes in the dry–wetting cycle and redox conditions. Broadening the collection of trace gases that can be monitored in the subsurface is critical for monitoring biogeochemical cycles, ecosystem health, and management practices at scales relevant to the soil system.

scholarly journals Monitoring Electrical Biasing of Pb(Zr0.2Ti0.8)O3 Ferroelectric Thin Films In Situ by DPC-STEM Imaging

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4749
Author(s):  
Alexander Vogel ◽  
Martin F. Sarott ◽  
Marco Campanini ◽  
Morgan Trassin ◽  
Marta D. Rossell
Keyword(s):  
Thin Film ◽  
Real Time ◽  
Data Storage ◽  
Ferroelectric Properties ◽  
Polarization State ◽  
Ferroelectric Materials ◽  
Time Data ◽  
Transmission Electron ◽  
The Impact

Increased data storage densities are required for the next generation of nonvolatile random access memories and data storage devices based on ferroelectric materials. Yet, with intensified miniaturization, these devices face a loss of their ferroelectric properties. Therefore, a full microscopic understanding of the impact of the nanoscale defects on the ferroelectric switching dynamics is crucial. However, collecting real-time data at the atomic and nanoscale remains very challenging. In this work, we explore the ferroelectric response of a Pb(Zr0.2Ti0.8)O3 thin film ferroelectric capacitor to electrical biasing in situ in the transmission electron microscope. Using a combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and differential phase contrast (DPC)-STEM imaging we unveil the structural and polarization state of the ferroelectric thin film, integrated into a capacitor architecture, before and during biasing. Thus, we can correlate real-time changes in the DPC signal with the presence of misfit dislocations and ferroelastic domains. A reduction in the domain wall velocity of 24% is measured in defective regions of the film when compared to predominantly defect-free regions.

scholarly journals Detection of Severe Human Metapneumovirus Infection by Real-Time Polymerase Chain Reaction and Histopathological Assessment

2005 ◽  
Vol 192 (6) ◽  
pp. 1052-1060 ◽  
Author(s):  
Kaharu C. Sumino ◽  
Eugene Agapov ◽  
Richard A. Pierce ◽  
Elbert P. Trulock ◽  
John D. Pfeifer ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
In Situ Hybridization ◽  
Respiratory Tract ◽  
Real Time ◽  
Human Metapneumovirus ◽  
Chain Reaction ◽  
Hmpv Infection ◽  
Polymerase Chain ◽  
The Impact

Abstract BackgroundInfections with common respiratory tract viruses can cause high mortality, especially in immunocompromised hosts, but the impact of human metapneumovirus (hMPV) in this setting was previously unknown MethodsWe evaluated consecutive bronchoalveolar lavage and bronchial wash fluid samples from 688 patients—72% were immunocompromised and were predominantly lung transplant recipients—for hMPV by use of quantitative real-time polymerase chain reaction (PCR), and positive results were correlated with clinical outcome and results of viral cultures, in situ hybridization, and lung histopathological assessment ResultsSix cases of hMPV infection were identified, and they had a similar frequency and occurred in a similar age range as other paramyxoviral infections. Four of 6 infections occurred in immunocompromised patients. Infection was confirmed by in situ hybridization for the viral nucleocapsid gene. Histopathological assessment of lung tissue samples showed acute and organizing injury, and smudge cell formation was distinct from findings in infections with other paramyxoviruses. Each patient with high titers of hMPV exhibited a complicated clinical course requiring prolonged hospitalization ConclusionsOur results provide in situ evidence of hMPV infection in humans and suggest that hMPV is a cause of clinically severe lower respiratory tract infection that can be detected during bronchoscopy by use of real-time PCR and routine histopathological assessment

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