Detection Of Small Amounts Research Articles

Adversarial Fusion Network for Forest Fire Smoke Detection

Recent advances suggest that deep learning has been widely used to detect smoke for early forest fire warnings. Despite its remarkable success, this approach has a number of problems in real life application. Deep neural networks only learn deep and abstract representations, while ignoring shallow and detailed representations. In addition, previous models have been trained on source domains but have generalized weakly on unseen domains. To cope with these problems, in this paper, we propose an adversarial fusion network (AFN), including a feature fusion network and an adversarial feature-adaptation network for forest fire smoke detection. Specifically, the feature fusion network is able to learn more discriminative representations by fusing abstract and detailed features. Meanwhile, the adversarial feature adaptation network is employed to improve the generalization ability and transfer gains of the AFN. Comprehensive experiments on two self-built forest fire smoke datasets, and three publicly available smoke datasets, validate that our method significantly improves the performance and generalization of smoke detection, particularly the accuracy of the detection of small amounts of smoke.

Statistical criteria for limiting the measurement of radionuclide activity by plastic scintillators

The paper is devoted to the estimation of the characteristic limits (statistical criteria) for the detection of small amounts of ionizing radiation by a measuring device under conditions of a natural radioactivity background of the environment: the decision threshold, the detection limit, the minimum detectable activity and the confidence interval. The assessment procedures were carried out in accordance with the national harmonized standard DSTU ISO 11929-3:2009. The threshold for making a decision on the presence of 137Cs and 60Co radionuclides in objects of the external environment and the limit of their detection using a measuring device equipped with plastic scintillators manufactured by the Institute of Scintillation Materials of the National Academy of Sciences of Ukraine were estimated. The influence of the energy of the detected radiation, the dimensions of the scintillators and the geometry of the irradiation on the estimation of the characteristic limits were investigated. Keywords: scintillator; decision threshold; detection limit; confidence interval; minimum detectable activity.

Surface-enhanced Raman spectroscopy of neonicotinoid insecticide imidacloprid, assisted by gold and silver nanostructures

Advanced silver and gold nanostructures were fabricated on alumina ceramic by thermal deposition technique. They were applied as active substrates for surface-enhanced Raman spectroscopy analyses of the neonicotinoid insecticides Nuprid 200 SP and Warrant 700 WG, both containing imidacloprid, in quantities much smaller than usually applied in the agricultural medicine. The efficiency of the fabricated structures was simulated by finite difference time domain (FDTD) method. The limit of detection of imidacloprid was estimated to be about ≈0.05 mM. The detection of small amounts or residue of harmful pollutants was forwarded to bearing on the environment and especially on the honey bees’ health.

Surface-Enhanced Raman Spectroscopy (SERS) of Neonicotinoid Insecticide Thiacloprid Assisted by Silver and Gold Nanostructures.

This study expresses our results on surface-enhanced Raman spectroscopy (SERS) analyses of neonicotinoid insecticide thiacloprid, i.e., Calypso 480 SC, in quantities much smaller than usually applied in the agricultural medicine. Advanced Ag and Au nanostructures created by the thermal deposition technique on Al2O3 ceramic were applied as active substrates for SERS analyses. The minimum concentration of thiacloprid detected was 380 µM and the enhancement factor was estimated to be about 3 × 103. The intensity of the SERS peaks increased by an order of magnitude after pulsed laser annealing of the films and formation of nanoparticle arrays and the enhancement factor reached ≈104, respectively. The proposed study has direct bearing on the environment and human health by detection of small amounts or residue of harmful pollutants using a relatively cheap and easy method to produce active SERS substrates.

A Sensitive Assay for Proteases in Bioaerosol Samples: Characterization and Quantification of Airborne Proteases in Salmon Industry Work Environments.

Proteases are probably underestimated exposure agents in bioaerosols. Their roles as barrier disrupters in allergic sensitization and activators of innate inflammation call for more attention in exposure-response studies. The main objectives of this study was (i) to establish a suitable method for detection of small quantities of proteases in filtered air samples and (ii) to utilize the method to characterize exposure to proteases in a salmon industry work environment. Analysis of proteases in filtered air samples was based on zymography, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis with 0.1% gelatin as substrate added in the polyacrylamide gel. Gelatinase activity was evident as cleared (unstained) regions. The area of these regions was quantified using image analysis (UVP Vision Works®). Standard curves with known amounts of active porcine trypsin were added to each gel. Validation of 11 non-linear standard curves showed R2 (range) = 0.8989-0.9882, limit of detection = 0.056 nM, lower limit of quantification = 0.161 nM, and coefficients of variations (range) = 20-28%. Sampling of bioaerosols in salmon industry was performed using polytetrafluoretylene filters with an airflow of 3 l min-1. All samples contained visible bands close to the size of porcine trypsin (23.3 kDa). The bands did not disappear in the presence of EDTA but abolished by Pefabloc, demonstrating that the enzyme is a serine protease, most likely salmon trypsin. Airborne levels of active protease were below the statistical detection limit in the filleting department but quantifiable in extract samples from the slaughter department. Three filtered air samples from the slaughter department showed air concentrations of 6.2, 16.5, and 27.0 ng m-3 air. We conclude that zymography is a sensitive and reliable method for exposure assessment of active proteases in indoor environmental samples. We recommend this assay for use in occupational studies to characterize and quantify exposure to active proteases in bioaerosols.

Detection of Non-Traumatic Knee Effusion among Asymptomatic Individual with Different type of Lifestyle and Selected Sociodemographic Factors Using Fluid Shift Test and Ultrasonography

Background history: Non-traumatic knee effusion might be the result of overuse leading to wear and tear processes or systemic diseases. Knee effusion-synovitis was a predictive of some structural abnormalities in the joint suggesting a potential role in early osteoarthritis changes. It is postulated that the active life style with prolonged standing hours predisposed for the increase prevalence of non-traumatic knee effusion even in the young age.Method: Final year medical students and clerical office staffs from Royal college of Medicine Perak were randomly selected. Those who had some kind of physical activities (walking, jogging or any kind of sports) for more than half an hour a day at least three times per week among the students and the clerical office staffs were included in active life style group and the remaining were listed in sedentary life style group. All were assessed for knee effusion by two orthopaedic surgeons clinically and then assessed by ultrasound examination on the same day. All were less than 30 years of age.Results: Data from 46 staffs and 53 students (total 99) were analysed. Number of participants in active life style group was 72 and that in sedentary life style groups was 27. Among the 99 participants, 53 (53.53%) had positive fluid shift test and 46 (46.5%) had effusion on ultrasound examination. The respondents who practice active lifestyle and respondents with BMI more than 25 had more prevalence than non-active respondents and respondents with BMI less than 25 respectively.Conclusion: The persons with active life style had more chance of having knee effusion. The five-point scale method of fluid shift test or stroke test is a reliable test for detection of small amounts of fluid in knee.

Determination of copper in sugarcane spirit by flame atomic absorption spectrometry using a ternary solvent mixture (water-ethanol-acetone)

The present work describes the use of a homogeneous ternary mixture of the solvents water, ethanol, and acetone to improve the determination of copper in sugarcane spirit by flame atomic absorption spectrometry. The solvent ratio used (on a volume basis) was 5.0:5.0:15.0 (water:ethanol:acetone). The analytical curve for copper was linear up to a concentration of 6.00 mg L-1 of copper, and could be described by the equation: Δabs = 0.1778CCu + 0.0048 (r2 = 0.9999), and limits of detection and quantification (calculated using the standard deviation of the blank) were 0.01 and 0.05 mg L-1 of copper, respectively. Use of the proposed homogeneous ternary solvent system provided good stability and a significant increase in sensitivity compared to reference methodology. This increase in sensitivity enables the detection of smaller quantities of copper in sugarcane spirit. The method was applied to determine copper in commercial brands of sugarcane spirits. The results obtained by the proposed method were favorably compared with those given by the reference method.

Passive Detection of Small Low-Emission Sources: Two-Dimensional Numerical Case Studies

In Allmaras et al. [Inverse Prob. Imaging, Vol. 7, No. 1, p. 47 (2013)], we present the mathematical foundations for the passive detection of small low-emission radioactive sources buried in background noise using Compton gamma cameras. Here, we apply these techniques to the detection of small amounts of special nuclear material in various cargo container geometries. Simulated two-dimensional data are used. We demonstrate the feasibility of such an approach using various realistic cargo container loadings and assess the effect of angular detection errors in Compton cameras.

DNA Detection Using SiC Nanowire Based Transistor

The fast and direct detection of small quantities of biomolecules improves early medical diagnosis of certain serious diseases as cancers and can be used to detect in situ the presence of pathogenic viruses or GMOs for food industry, protection environmental and bio-defense. Numerous research projects are conducted on nanoelectronic devices that can perform such detection with high sensitivity using nanostructures. Currently, these devices are made from Silicon nanowires [1]. For these applications, Silicon Carbide (SiC) material can advantageously replace Silicon as this semiconductor is now known to be biocompatible and to show a high chemical inertness [2]. Here, we present the electrical detection of DNA using a SiC Nanowire Field Effect Transistor (NWFET). The NWFETs are fabricated and then functionalized with DNA molecules. Between each step of the functionalization process, I-V characteristic measurements are performed. Comparative and simultaneous measurements are carried out on two SiC NWFETs: one is the sensor and the second one is used as a reference. Some interesting properties of the sensor are studied for the first time which opens the way to future developments of SiC nanowire based sensors.

Urine keratan sulfate (uKS) elevation in lysosomal disorders (LSD): Comparison of uKS levels in Morquio/MPS IV versus non-Morquio LSD

CO RR EC TE D P RO OF patients affected with different types of MPS, such as Hurler, Hurler/ Scheie and Scheie (MPS I/H, IH/S, I/S), Hunter (MPS II), Sanfilippo (MPS III), Morquio (MPS IV) and Maroteaux–Lamy (MPS VI) syndromes. Therefore, we have developed a quantitative methodology for the analysis of urine samples using an ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) multiplex approach. Specific glycosaminoglycans such as dermatan sulfate (DS), heparan sulfate (HS), and keratan sulfate (KS) were specifically targeted for mass spectrometry analysis. Twenty-five microliters of urine was evaporated at room temperature under a nitrogen flow. A methanolysis reaction was performed by adding methanol–HCl·3N to the dried urine sample, followed by heating at 65 °C for 60 min. After a second nitrogen evaporation, the residue was suspended in 200 μl of a solution containing deuterated internal standards synthesized in-house. Two microliters were injected onto an Acquity I-Class UPLC coupled to a Xevo TQ-S mass spectrometry system (Waters Corp.). The high sensitivity and good resolution of this methodology allowed the detection of small quantities of urinary GAG. Urinary excretion of specific GAG permitted a good differentiation between patients with MPS I, II, III, IV and VI and healthy reference controls. Except for MPS I and II which are characterized by the same GAG excretion profile, each MPS type was distinguished from one another due to a specific GAG profile. This UPLC–MS/MS quantitation of dermatan sulfate, heparan sulfate, and keratan sulfate is specific and sensitive for the detection of MPS disorders. This methodology might be applicable to high-risk screening and reliable for the diagnosis, and monitoring of treated MPS patients.

A Method to Measure Hydrolytic Activity of Adenosinetriphosphatases (ATPases)

The detection of small amounts (nanomoles) of inorganic phosphate has a great interest in biochemistry. In particular, phosphate detection is useful to evaluate the rate of hydrolysis of phosphatases, that are enzymes able to remove phosphate from their substrate by hydrolytic cleavage. The hydrolysis rate is correlated to enzyme activity, an extremely important functional parameter. Among phosphatases there are the cation transporting adenosinetriphosphatases (ATPases), that produce inorganic phosphate by cleavage of the γ-phosphate of ATP. These membrane transporters have many fundamental physiological roles and are emerging as potential drug targets. ATPase hydrolytic activity is measured to test enzyme functionality, but it also provides useful information on possible inhibitory effects of molecules that interfere with the hydrolytic process. We have optimized a molybdenum-based protocol that makes use of potassium antimony (III) oxide tartrate (originally employed for phosphate detection in environmental analysis) to allow its use with phosphatase enzymes. In particular, the method was successfully applied to native and recombinant ATPases to demonstrate its reliability, validity, sensitivity and versatility. Our method introduces significant improvements to well-established experimental assays, which are currently employed for ATPase activity measurements. Therefore, it may be valuable in biochemical and biomedical investigations of ATPase enzymes, in combination with more specific tests, as well as in high throughput drug screening.

Magnetic particle-based ultrasensitive biosensors for diagnostics

The process of sensitive and accurate detection of small quantities of disease biomarkers is critical for the clinical diagnosis of disease. In this regard, magnetic particles (MPs) have been widely used because of their unique magnetic properties allowing for efficient target capture, enrichment and convenient separation. These properties, coupled with great signal amplification, have enabled MP-based biosensors to achieve ultrasensitivities. Over the past few years, several ultrasensitive MP-based biosensors suitable for early clinical diagnostics have been reported. This article highlights some of the most recent developments, with a focus on MP-based ultrasensitive assays that use an antibody or aptamer as the target-binding agent, and that utilize efficient signal amplification/readout strategies.

Design of a novel sensor based on tapered photonic crystal with negative refraction structures

We report a novel design of an ultracompact sensor consisting of two-dimension photonic crystal with negative refraction coupled to a taper ended by multicavity structure. It is shown that this system exhibits promising properties in the area of sensing. The presence of nanocavities enables the detection of small amount of analytes. By controlling their radii, a large quality factor, Q is reached. It is demonstrated that the quality factor is a key parameter in determining the sensitivity to the analytes.

Distinct chitinases are expressed during various growth phases of the human pathogen Paracoccidioides brasiliensis

The aim of this work was the partial purification and subsequent evaluation of chitinase expression during the various growth phases of Paracoccidioides brasiliensis. Initially, PbCTS1r was expressed as a recombinant protein and displayed enzymatic activity against 4-MU-[N-acetylglucosamine (GlcNAc)]3 and 4-MU-(GlcNAc)2. Two proteins, 45 kDa and 39 kDa in size, were partially purified from P. brasiliensis yeast crude extract using cation-exchange chromatography coupled with HPLC and were characterised as PbCTS1 and PbCTS2, respectively. Anti-PbCTS1r antibody recognised two proteins in the crude extracts of yeast and the transitional stage between mycelial and yeast phases. In crude extracts of mycelium, only the 45 kDa protein was detected. However, quantitative real-time polymerase chain reaction led to the detection of small quantities of Pbcts2 transcript in the mycelial phase. In the yeast cell wall extract, only the 39 kDa protein was detected. Moreover, both proteins were secreted by the yeast parasitic phase, suggesting that these proteins participate in the modulation of the fungal environment. Phylogenetic analysis of the predicted PbCTS1 and PbCTS2 proteins indicated that they code for distinct chitinases in P. brasiliensis. During evolution, P. brasiliensis could have acquired the paralogues Pbcts1 and Pbcts2 for growth and survival in diverse environments in both saprophytic and parasitic phases.

Tensioned Metastable Fluid Detectors in Nuclear Security for Active Interrogation of Special Nuclear Materials―Part B

This paper (constituting Part B) addresses active interrogation for detecting Special Nuclear Materials (SN- Ms) and includes description of the transformational Tensioned Metastable Fluid Detector (TMFD) based method for optimal monitoring. One of the greatest difficulties in detection of SNMs by active interrogation is the task of distinguishing between the probing particles and the secondary particles that indicate the presence of SNMs. The TMFD’s selective insensitivity and γ photon blindness features are advantageous for alleviating this problem. The working principle of the TMFD is discussed along with its applications for security. The experimental work to date involving detection of small quantities of uranium with conventional detectors is discussed along with results of fission neutron detection. Statistically significant detection was achieved within 5 minutes of counting to ascertain and measure conclusive evidence for the presence of a 55g sample of uranium containing 235U. Results of simulations of three active detection techniques utilizing a TMFD system are presented. The process for using the TMFD to discriminate active source particles using timing and energy are described. These simulations indicate that it should be possible to utilize the TMFD system for optimal neutron-based interrogation of SNMs.

Molecular ecology of marine sediments: determination of Real-Time PCR efficiency for quantifying microbial cells

Polymerase chain reaction (PCR) efficiency is the rate at which a PCR amplicon is generated. More efficient amplification of the DNA fragment (amplicon) will generate more products in fewer cycles, thus improving accuracy and sensitivity of quantitative PCR. The efficiency of Real-Time PCR to detect and quantify microbial cells was compared in marine sediment samples of different origin and chemical composition, and in standard samples. Real-Time PCR efficiencies of marine sediment samples ranged from 1.48±0.1 to 1.83±0.1 and were significantly different from those of standard samples, most probably due to different concentrations of PCR inhibitors. The Real-Time PCR efficiency was higher using species-specific primers (>1.7), and lower using universal primers (<1.7). Generally, when the PCR efficiency was higher, its detection limit was lower. In addition, the sensitivity of the Real-Time capillary assay over the traditional assay was generally greater. We suggest that for quantifying microbial cells in marine sediment samples using Real-Time PCR, standard curves should be constructed for both the standard and sediment samples, and a correction factor should be applied. For qualitative PCR a real-time capillary assay should be used for the detection of small quantities of DNA.

Sonography in acute pancreatitis--diagnosis, assessment of etiology and evaluating prognosis

Fifty consecutive patients suffering from acute pancreatitis were studied prospectively with regard to the role of ultrasound (US) in diagnosis, in detection of a biliary origin, and in initial assessment of prognosis. In six patients the pancreas could not be visualised, whereas in 19 only partial examination was possible. In 34% no diagnostic abnormalities were found. US was superior to computed tomography (CT) in respect to the detection of small amounts of ascites, but less suitable than CT for the detection of necrosis. Compared to endoscopic retrograde cholangiography US was of little help in detecting bile duct stones. Neither a lethal outcome nor a severe course could be predicted with sufficient accuracy. The positive predictive value for the presence of necrosis was 33% and the negative predictive value 67%. The data demonstrate a limited role of US in diagnosis and staging in acute pancreatitis.

The incidence of JAK2 V617F mutation in bcr/abl-negative chronic myeloproliferative disorders: assessment by two different detection methods

A recurrent specific JAK2 V617F mutation has been reported in bcr/abl-negative chronic myeloproliferative diseases (cMPD), including polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF). The mutation is detectable in a variable proportion of neoplastic clones, depending on the molecular methods employed. In this study, we attempted to establish the JAK2 V617F mutation frequency in two partially overlapping cMPD patient series by two different PCR-based techniques. Using an allele-specific polymerase chain reaction assay (AS-PCR), the JAK2 V617F mutation was detected in 124/158 (78.5%) cMPD patients; in particular, 90.2, 72.1, 63.2 and 50% of PV, ET, IMF and unclassified (U)-MPD cases, respectively, showed the mutation. Employing a semiquantitative 5′ fluorogenic TaqMan assay, the JAK2 V617F mutation was identified in a much larger percentage of cMPDs patients (118/127: 92.9%). Rates of mutation in PV, ET, IMF and U-MPD cases were 95.9, 85.7, 91.7 and 92.9%, respectively. Furthermore, a statistically higher percentage of JAK2 mutated alleles was detected by TaqMan assay in PV (68 ± 3.5, mean value ± SEM) and IMF (64 ± 9.3) cases as compared with ET (35 ± 5.4). Finally, a significant correlation between JAK2 V617F mutational status and hematocrit (Ht), white blood cell and platelet counts in PV patients, and Ht values in ET cases, was observed by AS-PCR. Overall, these data indicate that TaqMan technology significantly improved sensitivity in detecting the JAK2 mutation in cMPD patients and may be worth of further evaluations as a clinically useful tool for detection of small amounts of mutated clones.

Comparative Analysis of Luminol Formulations

ABSTRACTLuminol is a valuable tool for crime scene examiners. The use of this reagent, primarily at crime scenes, allows the visualisation of occult or diluted blood, and the detection of small quantities of blood. Various different luminol formulations have been proposed over the years. In this study we have compared four different formulations with respect to luminescence and longevity. DNA profiling of blood treated with the four formulations with AMPFISTR® SGM Plus™ and low copy number (LCN) DNA analysis allow us to make recommendations of the most appropriate luminol formulations to be used under particular case circumstances.

Optimal processing of information from detectors used for detecting explosives by neutron-radiation analysis

The optimization is accomplished on the basis of methods used for checking statistical hypotheses. Two possible methods for processing information from γ-ray detectors are examined: setting a threshold according to a general likelihood ratio including all combinations of detectors or separate combinations of detectors. In the second case, all possible combinations of detectors must be sorted when the measurements are analyzed. Calculations for a specific setup with six detectors show that sorting detector combinations permits detection of smaller quantities of explosives than can be done with a general likelihood ratio. A sequential analysis instead of sorting detector combinations permits identifying explosives more quickly than can be done with a general likelihood ratio.