Search results for "Detection"
showing 10 items of 2543 documents
Solid-state-biased coherent detection of ultra-broadband terahertz pulses
2017
Significant progress in nonlinear and ultrafast optics has recently opened new and exciting opportunities for terahertz (THz) science and technology, which require the development of reliable THz sources, detectors, and supporting devices. In this work, we demonstrate the first solid-state technique for the coherent detection of ultra-broadband THz pulses (0.1-10 THz), relying on the electric-field-induced second-harmonic generation in a thin layer of ultraviolet fused silica. The proposed CMOS-compatible devices, which can be realized with standard microfabrication techniques, allow us to perform ultra-broadband detection with a high dynamic range by employing probe laser powers and bias v…
3,3?,5,5?-Tetramethylbenzidme for the colorimetric determination of manganese in water
1998
Manganese can be determined by colorimetry with previous oxidation of Mn(II) in a strong basic medium, using 3,3′,5,5′-tetramethylbenzidine as a chromogenic reagent. The molar absorptivity of the reaction product is 3.4 × 104 mol−1l cm−1l, the detection limit 3 ng/ml, the RSD (0.5 mg/l,n = 8) 0.9% and the calibration range (1-cm cells) 0.02–0.8 mg/1 V(V), Cr(VI) and Co(II) are the most significant interferences. The new method was compared with an AAS procedure (air-acetylene flame) with previous solvent extraction and also with a colorimetric method for the determination of manganese in sea and drinking water.
Consequences of Sarcopenia in Older People: The Epidemiological Evidence
2021
Sarcopenia is a common condition in older people. Increasing literature is showing its importance for negative health outcomes, also beyond the perimeter of geriatric medicine. In this chapter, we will discuss the consequences of sarcopenia. Overall, epidemiological research suggests that sarcopenia is significantly associated with falls and fractures also suggesting a strong association between muscle and bone loss conditions, as in the case of osteosarcopenia. Moreover, sarcopenia is associated with disability, hospitalization (particularly in older people already hospitalized), and finally mortality. Increasing research is also showing that sarcopenia is associated with negative outcomes…
Use of bone scintigraphy in the early diagnosis of bisphosphonate related osteonecrosis of the jaw. Case report and review of the literature
2018
The main aim of the present report is to show the potential utility of bone scintigraphy for the diagnosis of jaw osteonecrosis. We report the history of a 62-year-old woman underwent breast cancer surgery in 2010. Moreover, patient received postoperative radiotherapy and chemotherapy. Intravenous bisphosphonates were also added to the treatment strategy to reduce the risk of bone metastasis. However, a hypermetabolic focus on left hemimandible was evidenced with a bone scintigraphy during follow up. After a careful study, the diagnosis of Bisphosphonate Related Ostneonecrosis of the Jaw (BRONJ) was carried out. This case highlights that bone scintigraphy may be extremely helpful for the ea…
Pedagogical approaches for e-assessment with authentication and authorship verification in Higher Education
2019
Checking the identity of students and authorship of their online submissions is a major concern in Higher Education due to the increasing amount of plagiarism and cheating using the Internet. The literature on the effects of e-authentication systems for teaching staff is very limited because it is a novel procedure for them. A considerable gap is to understand teaching staff' views regarding the use of e-authentication instruments and how they impact trust in e-assessment. This mixed-method study examines the concerns and practices of 108 teaching staff who used the TeSLA—Adaptive Trust-based e-Assessment System in six countries: the UK, Spain, the Netherlands, Bulgaria, Finland and Turkey.…
Identification of 5,6,7,8-tetrahydropterin and 5,6,7,8-tetrahydrobiopterin in Drosophila melanogaster.
1988
Summary Using reversed-phase high-performance liquid chromatography with electrochemical detection we have demonstrated the occurrence of 5,6,7,8-tetrahydropterin and 5,6,7,8-tetrahydrobiopterin in Drosophila melanogaster . The former is the first time that has been detected in vivo . The identification has been based on the retention times, hydrodinamic voltagrams and the differential concentration in three strains of Drosophila melanogaster . Compared to the wild type, the Punch 2 mutant has diminished levels of both pteridines, whereas Henna-recessive 3 lacks completely tetrahydropterin and has increased levels of tetrahydrobiopterin, as expected according to their biochemical lesions.
GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences
2018
The LIGO Scientific and Virgo Collaborations have announced the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star background will add to the background from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude $\Omega_{\rm…
Improving uptake of screening for colorectal cancer: a study on invitation strategies and different test kit use
2015
Objective The aim of this study was to compare the uptake of mail-delivered tests for colorectal cancer screening. We assessed the effect of an advance notification letter and a reminder letter, and analysed the proportion of inappropriately handled tests. Materials and methods Fifteen thousand randomly selected residents of Latvia aged 50–74 years were allocated to receive one of three different test systems: either a guaiac faecal occult blood test (gFOBT) or one of two laboratory-based immunochemical tests (FIT) – FOB Gold or OC-Sensor. Half of the target population received an advance notification letter; all nonresponders were sent a reminder letter. Results The uptake of screening was…
A tandem-flow assembly for the chemiluminometric determination of hydroquinone
2003
A direct chemiluminescent procedure for determination of hydroquinone based on the emergent flow methodology known as multicommutation or tandem-flow is presented for first time. The manifold was based on a set of three channels and three solenoid valves; and, the determination was performed at 60degreesC and at flow-rate of 7.5 ml min(-1). The complete cycle lasted 35 s, which resulted in a sample flow trough of 103 h(-1). The chemical process was the hydroquinone oxidation with the system sulphuric acid-potassium permanganate; and the light emission was clearly enhanced by the presence of quinine sulphate and benzalkonium chloride reaching a detection limit of 30 Rg l(-1). The dynamic int…
Development of a real-time PCR assay for detection and quantification of enterotoxigenic members of Bacillus cereus group in food samples
2009
A highly sensitive real-time PCR (qPCR) procedure, targeting the phosphatidylcholine-specific phospholipase C gene (pc-plc), was developed for specific detection and quantification of strains belonging to Bacillus cereus group. The target region was selected based on the enterotoxigenic profiles of 75 Bacillus strains. The inclusivity and exclusivity of the RTi-PCR assay were assessed with 59 isolates of the B. cereus group, 16 other Bacillus spp., and 4 non-Bacillus strains. The assay was also used to construct calibration curves for different food matrices, and it had a wide quantification range of 6 log units using both serial dilutions of purified DNA and calibrated cell suspensions of …