Artykuły w czasopismach: „NPD DETECTOR”

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Rao, Yuan, i Arno de Klerk. "Nitrogen-containing aromatic compounds: quantitative analysis using gas chromatography with nitrogen phosphorus detector". Applied Petrochemical Research 11, nr 2 (6.03.2021): 129–36. http://dx.doi.org/10.1007/s13203-021-00265-z.

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AbstractThe nitrogen-containing aromatic compounds found in the petrochemical industry are varied and extend beyond classes such as the anilines, pyrroles and pyridines. Quantification of these nitrogen-containing compounds that may occur in complex mixtures has practical application for quality assurance, process development and the evaluation of conversion processes. Selective detection of nitrogen-containing species in complex mixtures is possible by making use of gas chromatography coupled with a nitrogen phosphorous detector (GC-NPD), which is also called a thermionic detector. Despite the linearity of the NPD response to individual nitrogen-containing compounds, the response factor is different for different compounds and even isomers of the same species. Quantitative analysis using an NPD requires species-specific calibration. The reason for the sensitivity of the NPD to structure is related to the ease of forming the cyano-radical that is ionized to the cyanide anion, which is detected. The operation of the NPD was related to the processes of pyrolysis and subsequent ionization. It was possible to offer plausible explanations for differences in response factors for isomers based on pyrolysis chemistry. Due to this relationship, the NPD response can in the same way be used to provide information of practical relevance beyond its analytical value and a few possible applications were outlined.

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Satto, Isao, Sadaji Yamada, Harumi Oshtma, Yoshttomo Ikai, Hisao Oka i Junko Hayakawa. "Analysis of Methyl Isothiocyanate in Wine by Gas Chromatography with Dual Detection". Journal of AOAC INTERNATIONAL 77, nr 5 (1.09.1994): 1296–99. http://dx.doi.org/10.1093/jaoac/77.5.1296.

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Abstract Methyl isothiocyanate (MITC) was extracted from a 5 mL wine sample with 2 mL dichloromethane, and the extract was washed with 5% sodium chloride solution. MITC was determined by gas chromatography with a dual nitrogen-phosphorus detector (NPD) and a flame photometric detector (FPD, S mode) (DB-210 column, 30 m × 0.53 mm id, column temperature, 70°C). The limit of detection and quantitation of MITC with NPD–GC were 0.003 and 0.01 ppm, respectively. Average recoveries of MITC added to wine at 1 and 0.1 ppm were over 95%. This method is simple and rapid for routine analysis of MITC in wine.

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Frenich, Antonia Garrido, Maria Del Carmen Pablos Espada, Jose Luis Martínez Vidal i Luis Molina. "Broad-Spectrum Determination of Pesticides in Groundwater by Gas Chromatography with Electron Capture Detection, Nitrogen–Phosphorus Detection, and Tandem Mass Spectrometry". Journal of AOAC INTERNATIONAL 84, nr 6 (1.11.2001): 1751–62. http://dx.doi.org/10.1093/jaoac/84.6.1751.

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Abstract Gas chromatography with electron capture detector (ECD), nitrogen–phosphorus detector (NPD), and tandem mass spectrometry (MS/MS) was used to identify 36 pesticides, widely used to control various pest and diseases in vegetables, in water after a preconcentration step on C18 cartridges. The recoveries obtained ranged from 70 to 135% at a fortification level of 100 ng/L with relative standard deviations of <36.2%. The limits of detection and quantitation were ≤48 and ≤160 ng/L, respectively. Important advantages of MS/MS over ECD and NPD in the determination of pesticides are also presented. The proposed analytical methodology was applied to the determination of pesticides in groundwater samples from an agricultural area, the Campo de Dalías (Almería, Spain). The most frequently encountered pesticides were endosulfan sulfate and metalaxyl, whereas the pesticide found at the highest concentration was fenamiphos.

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Paulsdorf, Jürgen, Hans-Dieter Wiemhöfer, Andrej Orinák, Petr Zámostný, Zdeněk Bělohlav i David Baxter. "Application of pyrolysis-capillary gas chromatography with NPD detection in thermal degradation of polyphosphazenes study". Open Chemistry 5, nr 1 (1.03.2007): 271–90. http://dx.doi.org/10.2478/s11532-006-0047-8.

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AbstractPolyphosphazenes represent a unique class of polymers with a backbone composed of alternating phosphorous and nitrogen atoms. The thermal behaviour and decomposition of a variety of polyphosphazenes depends on the type of side groups present. Especially those that bear aryloxy side groups, possess a high temperature stability as well as excellent flame resistance. Pyrolysis-capillary gas chromatography has been used in a study of three polyphosphazene samples for thermal stability characterisation. Degradation products were detected with three single detectors for flame ionisation (FID), nitrogen-phosphorous sensitivity (NPD) and mass spectrometry (MSD) at different pyrolysis temperatures ranging from 300°C up to 800°C. The NPD responses for phosphorous or nitrogen fragments of polyphosphazenes have been used for the construction of degradation product schemes and the examination of the thermal stability of the polyphosphazene’s backbone. Partial identification of the degradation products present in the gaseous phase was achieved by MSD. The polyphosphazenes thermal degradation conversion rates were at a maximum at 450–500°C. At various pyrolysis temperatures, the calculated N/P peak area ratio is a function of the degree of polyphosphazene-N=P-chain degradation, and reflective of the nitrogen — phosphorous detector sensitivity. NPD proved to be suitable tool for characterization of polyphospazene thermal stability.

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Kim, Sim Hae, Jun-Ho Hwang i Kwang-Geun Lee. "Analysis of acrylamide using gas chromatography-nitrogen phosphorus detector (GC-NPD)". Food Science and Biotechnology 20, nr 3 (czerwiec 2011): 835–39. http://dx.doi.org/10.1007/s10068-011-0116-4.

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Abdel-Rehim, Mohamed, i Moustapha Hassan. "Effect of ammonia on the response of the nitrogen phosphorus detector (NPD)". Journal of Microcolumn Separations 6, nr 4 (lipiec 1994): 369–72. http://dx.doi.org/10.1002/mcs.1220060405.

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Soo, V. A., R. J. Bergert i D. G. Deutsch. "Screening and quantification of hypnotic sedatives in serum by capillary gas chromatography with a nitrogen-phosphorus detector, and confirmation by capillary gas chromatography-mass spectrometry." Clinical Chemistry 32, nr 2 (1.02.1986): 325–28. http://dx.doi.org/10.1093/clinchem/32.2.325.

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Abstract We describe a quantitative screen for hypnotic-sedative drugs in which we use capillary gas chromatography with a nitrogen-phosphorus detector (GC/NPD) as the primary method and capillary gas chromatography-mass spectrometry (GC-MS) for confirmation. GC retention times of the acid-extracted underivatized drugs were stable (CVs less than 1%), and the detector response varied linearly over a 20-fold concentration range with a mean correlation coefficient for 11 drugs of 0.989. The limits of detection were satisfactory (0.5 mg/L in a 0.5-mL serum sample and 1-microL injection volume), as were precision (average CV 5.2% within day, 6.4% between day). The complementary use of capillary GC-MS not only unambiguously confirms presumptive peaks identified by GC, but also prevents reports of false positives and identifies compounds not included in the quantitative GC screen that may be listed in the GC-MS library.

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Alnedhary, Anass A., Abdualqawi A. Numan, Mahfoudh M. AL - Hammadi i Taiseer H. Al - Hoded. "Optimization, Validation and Application of Quantitative Method for the Determination of Acrylamide in Potato Chips Samples in Yemen Using GC-NPD". Pakistan Journal of Analytical and Environmental Chemistry 24, nr 1 (27.06.2023): 63–73. http://dx.doi.org/10.21743/pjaec/2023.06.06.

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Over the last two decades, numerous analytical methods for determining acrylamide concentration in a wide range of food products have been developed. Some studies focused on the methods of extracting acrylamide from complex food matrices. In the present study, solid Phase Extraction (SPE) and Gas Chromatography-Nitrogen Phosphorus Detector (GC-NPD) analysis were employed to develop a simple and cost-effective acrylamide determination method. Method validation and optimization steps were carried out and used to determine acrylamide concentrations in potato chips purchased from Yemeni markets. In the concentration range of 0.1- 5 ppm, the validated method demonstrated good sensitivity within a 0.012 ppm limit of detection (LOD) and an excellent linearity of 0.996 correlation coefficient. Eighteen samples of potato chips purchased from local markets in Sana'a, Yemen, were analyzed using this method. Three of the 18 samples of interest contained various acrylamide concentration levels of 879.4, 795.6, and 754.7 ppb. These were higher than the EU Commission's indicative value for the acrylamide in potato chips (750 ppb). As a result, the optimized GC-NPD protocol proved to be useful for the acrylamide analysis, paving the way for the development of an acrylamide quantification prescreening tool in the food industry.

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Wang, Shiyu, Zhaohui Ma, Junnan Zhang, Wentao Jiao, Zhirui Qin, Qianhui Yuan, Chengcheng Xie, Wenyong Wu i Patrick Christopher Wilson. "Structure–Biodegradability Relationship of Nonylphenol Isomers in Two Soils with Long-Term Reclaimed Water Irrigation". Water 14, nr 8 (13.04.2022): 1258. http://dx.doi.org/10.3390/w14081258.

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Nonylphenol (NP), as one of the typical endocrine disrupter chemicals (EDCs), has a high detection concentration and frequency in reclaimed water. This research focused on the degradation of NP isomers in two typical reclaimed water irrigation fields in Daxing, China, and Florida, USA. The results showed that the half-lives of NP isomer degradation in the soil of China and Florida were 2.03–8.66 d and 5.16–11.83 d, respectively. The degradation of NP isomers was structure-specific. Isomers of NP5, NP2, NP11, and NP3 had the highest degradation rates in the two soils; NP12, NP7, and NP6 were the isomers with medium degradation rates; and NP4, NP1, NP10, NP9, and NP8 had the slowest degradation rates. Steric hindrance and mean information index for the magnitude of distance (IDWbar) were found to be the better indexes for measuring the degradation of NP isomers compared with the length of the side chain, the type of the substitute, and the molecular connectivity. This study offers insights into the characteristics of NP isomers and two reliable indicators for measuring the degradation of NP isomers, which could provide data support for the environmental fate and the health risk assessment of NP in the future.

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Christen, Philippe, Stefan Bieri i Orlando Muñoz. "Characterization of Positional and Configurational Tropane Alkaloid Isomers by Combining GC with NPD, MS and FTIR". Natural Product Communications 4, nr 10 (październik 2009): 1934578X0900401. http://dx.doi.org/10.1177/1934578x0900401006.

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A purified stem bark extract from Schizanthus grahamii was analyzed by combining capillary gas chromatography with a selective nitrogen phosphorus detector, mass spectrometry and Fourier transform infrared spectroscopy. Several positional and configurational tropane isomers were detected and their structural elucidation was tentatively determined based on mass spectra and confirmed by vapor phase infrared spectra. Electron impact mass spectra of the isomeric alkaloids were virtually superimposable, whereas the corresponding infrared spectra differed markedly. Retention indices were established under isothermal and temperature program conditions for further peak assignment and identification. In order to point out possible artifacts in the hot and surface-active injection port, different sample introduction techniques were evaluated, namely split, splitless and on-column injections.

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Hu, Ruikang, Lifeng Zhang i Zhaoguang Yang. "Picogram determination of N-nitrosodimethylamine in water". Water Science and Technology 58, nr 1 (1.07.2008): 143–51. http://dx.doi.org/10.2166/wst.2008.644.

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N-nitrosodimethylamine (NDMA) persistence within surface waters is a major concern for downstream communities exploiting these waters as drinking water supplies. The objective of this study is to develop a novel and efficient analytical method for NDMA via different technologies: pulsed splitless gas chromatography–nitrogen phosphorus detector (GC–NPD), large volume injection (LVI) gas chromatography–mass spectrometry (GC/MS) via programmable temperature vaporizer (PTV) inlet or PTV-gas chromatography– triple quadruple mass spectrometry (GC-MS/MS) and continuous liquid–liquid extraction. It was found that the sensitivity required for NDMA analysis by GC–NPD can only be achieved when the NPD bead is extremely clean. LVI via PTV can greatly improve GC-MS system sensitivity for analyzing NDMA. With the help of DB-624 (25 m × 200 μm × 1.12 μm) connected with DB-5MS (30 m × 250 μm × 0.25 μm) in series, PTV–GC/MS could overcome the matrix interference for the trace analysis of NDMA. Variable instrument conditions were studied in detail, with the optimized process being validated via precision and accuracy studies. PTV- triple quadruple GC-MS/MS system could efficiently remove the interference on a single DB-5MS (30 m × 250 μm × 0.25 μm) column with good sensitivity and selectivity. The developed methods have been successfully applied to test NDMA in different types of water samples with satisfactory results.

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AHUMADA F., Diego A., i Jairo A. GUERRERO D. "STUDY OF MATRIX EFFECT IN PESTICIDE ANALYSIS BY GAS CHROMATOGRAPHY". Vitae 17, nr 1 (26.03.2010): 51–58. http://dx.doi.org/10.17533/udea.vitae.4974.

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In order to study the matrix-induced chromatographic response enhancement (matrix effect), we selectthree different types of biotic matrices (Lactuca sativa L., Physalis peruviana L. and Solanum tuberosum)and a group of pesticides of different physicochemical characteristics including organochlorine,organophosphorus and pyrethroids pesticides. These pesticides are determined by gas chromatographyby electronic microcapture detector (μECD) and nitrogen-phosphorus detector (NPD), coupled inparallel. This study evaluates the matrix effect by analysis of covariance and linear regression. There arenearly 75% of the studied pesticides which have variations in the chromatographic response compared tosolvent signals. Furthermore, we notice that the nature of the matrix affect the chromatographic responseof 18 of the 33 pesticides and the amount of matrix injected affects the response of only 13 pesticides.

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das Neves, H. J. Chaves, A. M. V. Riscado i H. Frank. "Single derivatives for GC-MS assay of reducing sugars and selective detection by the nitrogen-phosphorus detector (NPD)". Journal of High Resolution Chromatography 9, nr 11 (listopad 1986): 662–66. http://dx.doi.org/10.1002/jhrc.1240091114.

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LUNDÉN, ANNE, VICTORIA GUSTAFSSON, MIROSLAVA IMHOF, ROLAND GAUCH i JACQUES-OLIVIER BOSSET. "High trimethylamine concentration in milk from cows on standard diets is expressed as fishy off-flavour". Journal of Dairy Research 69, nr 3 (sierpień 2002): 383–90. http://dx.doi.org/10.1017/s002202990200568x.

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To establish whether fishy off-flavour observed in cows' milk in Sweden is due to abnormal concentrations of trimethylamine (TMA) in milk, 15 milk samples from 13 cows of the Swedish Red and White breed (SRB) were analysed for this compound using dynamic headspace (DHS) gas chromatography (GC). A mass selective detector (MSD) was used for the qualitative and a flame ionization detector (FID) for the quantitative analyses. Further confirmation was obtained using a solid phase microextraction (SPME) followed by GC-olfactometry (GC-O) and GC-NPD (nitrogen and phosphorus detector). Samples were also evaluated by a two-person organoleptic panel for the presence of fishy off-flavour. Results showed that the seven milk samples with a fish-like taint contained >1 mg TMA/kg milk, whereas, with a single exception, the seven samples that were judged to be normal did not contain this compound. Furthermore, there were indications of a dose-dependent relationship between TMA concentration and fishy off-flavour score.

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Yasuhara, Akio, Jason K. Dennis i Takayuki Shibamoto. "Development and Validation of New Analytical Method for Acrolein in Air". Journal of AOAC INTERNATIONAL 72, nr 5 (1.09.1989): 749–51. http://dx.doi.org/10.1093/jaoac/72.5.749.

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Abstract A new method was developed to determine vapor-phase acrolein in air samples. Air containing vapor-phase acrolein was purged into impingers filled with a dichloromethane solution of JV-methylhydrazine. The resulting derivative, l-methyl-2-pyrazoline, was analyzed by gas chromatography using a nitrogen-phosphorous detector (NPD). The detection limit was 8.9 pg 1-methyl-2-pyrazoline, equivalent to 5.9 pg acrolein. The recovery efficiencies of vapor-phase acrolein were 98.0 ± 2.9% and 100.3 ± 3.1% for 150 and 15 μg, respectively. This method was satisfactorily applied for determination of acrolein formed from various heated fats. The amounts of acrolein formed in a headspace were 109 μg/L from lard, 164 Mg/L from corn oil, 5.1 μg/L from cotton seed oil, and 163 μg/L from sunflower oil.

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Yasuhara, Akio, i Takayuki Shibamoto. "Formaldehyde Quantitation in Air Samples by Thiazolidine Derivatization: Factors Affecting Analysis". Journal of AOAC INTERNATIONAL 72, nr 6 (1.11.1989): 899–902. http://dx.doi.org/10.1093/jaoac/72.6.899.

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Abstract A new method for the determination of trace levels of formaldehyde in air was developed and validated. The method is based on the reaction of formaldehyde with cysteamine to form thiazolidine. Air samples containing trace levels of formaldehyde were prepared from paraformaldehyde. The percent yield of formaldehyde from paraformaldehyde was 85.1 ± 1.14%. Air samples were bubbled into an aqueous cysteamine trap. Thiazolidine formed from formaldehyde and cysteamine in the trap was determined by gas chromatography with a fused silica capillary column and a nitrogen-phosphorus detector (NPD). The lowest detection level for thiazolidine was 17.2 pg, equivalent to 5.80 pg formaldehyde. The recovery efficiency of trace gas phase formaldehyde in air was greater than 90%. Formaldehyde levels in ambient laboratory air were 48.9-56.2 ppb (v/v).

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Malafatti, Lusiane, Patrícia Penido Maia, Matheus Coutinho Gonçalves Martins, Maria Elisa Pereira Bastos de Siqueira i Isarita Martins. "Single gas chromatography method with nitrogen phosphorus detector for urinary cotinine determination in passive and active smokers". Brazilian Journal of Pharmaceutical Sciences 46, nr 4 (grudzień 2010): 769–76. http://dx.doi.org/10.1590/s1984-82502010000400019.

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Nicotine is a major addictive compound in cigarettes and is rapidly and extensively metabolized to several metabolites in humans, including urinary cotinine, considered a biomarker due to its high concentration compared to other metabolites. The aim of this study was to develop a single method for determination of urinary cotinine, in active and passive smokers, by gas chromatography with a nitrogen phosphorus detector (GC-NPD). Urine (5.0 mL) was extracted with 1.0 mL of sodium hydroxide 5 mol L-1, 5.0 mL of chloroform, and lidocaine used as the internal standard. Injection volume was 1 μL in GC-NPD. Limit of quantification was 10 ng mL-1. Linearity was evaluated in the ranges 10-1000 ng mL-1 and 500-6000 ng mL-1, with determination coefficients of 0.9986 and 0.9952, respectively. Intra- and inter-assay standard relative deviations were lower than 14.2 %, while inaccuracy (bias) was less than +11.9%. The efficiency of extraction was greater than 88.5%. Ruggedness was verified, according to Youden's test. Means of cotinine concentrations observed were 2,980 ng mL-1 for active smokers and 132 ng mL-1, for passive smokers. The results revealed that satisfactory chromatographic separation between the analyte and interferents was obtained with a ZB-1 column. This method is reliable, precise, linear and presented ruggedness in the range evaluated. The results suggest that it can be applied in routine analysis for passive and active smokers, since it is able to quantify a wide range of cotinine concentrations in urine.

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Holland, Patrick T., Donald E. McNaughton i Colin P. Malcolm. "Multiresidue Analysis of Pesticides in Wines by Solid-Phase Extraction". Journal of AOAC INTERNATIONAL 77, nr 1 (1.01.1994): 79–86. http://dx.doi.org/10.1093/jaoac/77.1.79.

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Abstract A method is described for screening wine for 74 pesticide residues. Aliquots of wine (10 mL) are extracted with 500 mg C18–silica solid-phase extraction (SPE) columns after addition of carbophe-nothion internal standard at 0.1 mg/L. The column is washed with 20% ethanol–water (4 mL), and pesticide residues are eluted with 1 mL ethyl acetate. The extract is made up to 2 mL final volume with isooctane for screening by gas–liquid chromatography (GC) using a narrow-bore FSOT column (5% phenyl–95% methyl-silicone bonded phase) with effluent splitting to electron capture (ECD) and nitrogen–phosphorus (NPD) detectors. A second GC system, using a 50% phenyl–50% methyl-silicone FSOT column with effluent splitting to ECD and flame photometric detector (P mode), is used for confirmation. The SPE method was rapid, robust, and reproducible. Recovery of pesticides added at 0.2 mg/L were 70–110% for the majority of pesticides, with standard deviations (SDs) of 1–18%. Some highly polar pesticides gave low recoveries. At a fortification level of 1 mg/L in wine, 13 fungicides gave recoveries of 80–118%, with SDs of 2–14%. At 0.02 mg/L, some less stable pesticides exhibited enhanced recoveries due to the protective effects of coextractives during GC. Detection limits were 0.01–0.02 mg/L with no major interferences observed from a range of wines. The multiple GC column and detector combinations and the internal standard provided a high degree of assurance in the identification of residues in wine.

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Adardour, Haroun Errachid, i Samir Kameche. "Analysing Primary Signal Sensing Test in Cognitive Radio Networks Using an Alpha-Beta Filter and a Neyman-Pearson Detector". Algerian Journal of Signals and Systems 3, nr 2 (15.06.2018): 70–80. http://dx.doi.org/10.51485/ajss.v3i2.61.

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The signal strength sensing in the context of cognitive radio networks (CRNs), is very important to predict the primary signal of base station (PBS), particularly when the secondary user (SU) is in a congested environment, and also when is in motion towards the end of coverage of PBS. However, this article presents an analysis on the prediction of primary signal strength in CRNs using an Alpha-Beta Filter (ABF) and a Neyman-Pearson Detector (NPD). The challenge of this contribution is based on a realistic sensing of primary signal strength and to do that, we have assumed that the reporting channels between the SU and the PBS are composited with the shadowing and multipath fading (SMF), and the receiver noise has also added. In this regard, the obtained results were discussed through: the signal-to-noise ratio (SNR) uncertainty, the detection probability (PD) and the False Alarm Probability (PFA), where the average relative error of prediction for the PD will be equal to10-5.

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Delevic, Veselin, Refik Zejnilovic, Biljana Jancic-Stojanovic, Milica Zrnic-Ciric, Brizita Djordjevic i Ivan Stankovic. "The effect of heat treatments on the synthesis of acrylamide and its quantification by gas chromatography with a nitrogen-phosphorus detetector". Chemical Industry 70, nr 1 (2016): 31–36. http://dx.doi.org/10.2298/hemind141215009d.

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In this paper, the influence of thermal treatment (cooking, baking and frying) on the content of acrylamide in potato was followed by gas chromatography with nitrogen - phosphorus detector (GC-NPD). Sample preparation was performed in the conventional manner, applying heat treatment as follows: in boiling water at 110 0C for 30 minutes, by baking in an oven for 30 minutes at 2200 C, and frying in oil for 15 minutes at 250 0C. Quantification of acrylamide are preceded: homogenization of the sample, extraction, and evaporation of the extract. The calibration is performed in the concentration range 0-10 mg/kg and obtained value for R2 was higher than 0,99. Llimit of detection and limit of quantification were determined and obtained values were 0,26 mg/kg and 0,41 mg/kg, respectively. Recovery values were ranged from 102% to 110% and confirmed that metod is accurate. The proposed GC-NPD method is simple, reliable, and accurate for determination of the content of acrylamide in food samples. Obtained results show that the content of acrylamide in potato prepared by heat-cooking were below LOD while for samples trathed by baking or frying were in range from 0,6 mg/kg to 2,7 mg/kg. By comparing the content of acrylamide in potato we concluded that heat treatment has a major impact on the synthesis of acrylamide and it would be desirable to develop a process for the preparation of French fries and potato chips with low or no acrylamide content with textured attractive for consummation.

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Najamuddin, Najamuddin, Muhammad Imran, Mubasher Muhammad, Irfan Ashiq Muhammad, Muhammad Amjad i Ashraf Tahir Mohammad. "Detection of phosphine in abdominal cavity material of woman dead body and ingesta of cow using Gas Chromatography-Nitrogen Phosphorous Detector technique (GC-NPD)". Toxicologie Analytique et Clinique 34, nr 3 (wrzesień 2022): S148—S149. http://dx.doi.org/10.1016/j.toxac.2022.06.250.

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Manquián T., Nimia, Raúl Cristi V. i Daniel Apablaza S. "METODO DE DETECCION DEL HERBICIDA METSULFURON - METIL POR CROMATOGRAFIA GAS-LIQUIDA CON DETECTOR NITROGENO FOSFORO (NPD), EN MUESTRAS DE SUELO". Agro Sur 27, nr 1 (1999): 113–16. http://dx.doi.org/10.4206/agrosur.1999.v27n1-12.

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Łozowicka, Bożena. "The development, validation and application of a GC-dual detector (NPD-ECD) multi-pesticide residue method for monitoring bee poisoning incidents". Ecotoxicology and Environmental Safety 97 (listopad 2013): 210–22. http://dx.doi.org/10.1016/j.ecoenv.2013.07.010.

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Hussan, Hammad Ul, Muhammad Nabeel Amjad, Faisal Mumtaz, Barjeece Bashir i Adeel Ahmad. "Farmer’s Awareness on Pesticide Waste Management and Role of Pesticides in Water Contamination in Bahawalpur, Punjab, Pakistan". Geographic Base 8, nr 01 (31.12.2021): 63–72. http://dx.doi.org/10.3126/tgb.v8i01.43472.

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This study emphasizes the awareness and training of farmers on sustainable agricultural practices for restrictive use of pesticides to reduce water pollution caused by pesticides in rural areas. For this assessment, 150 feasible farmers were selected randomly using a convenient sampling technique. Data was collected through interviews (n=30) and questionnaires (n=120). Data was scrutinized in SPSS software. To examine freshwater contamination with pesticides, freshwater samples were collected from open water bodies (5 wells) in the area of tehsil Hasilpur (29.6902° N, 72.5796° E) and Qaimpur of Bahawalpur, Punjab, and analyzed for eight pesticides which are frequently used. ECD: Electron Capture Detector was used to detect the organochlorine pesticides, herbicides, and various halogenated hydrocarbons. NPD: Nitrogen Phosphorus Detector was used to detect nitrogen- or phosphorus[1]containing compounds. Approximately 80% of farmers revealed that they never got any training or informative 64 sessions for pest management other than using chemical pesticides. The remaining 20% were trained by some private non-toxic pesticide manufacturing firms operating in Pakistan. Although non-significant cooperation from the government bodies of the state, the correlation among respondents’ profiles and the extent of training they have received in total was positive. Results for pesticide contamination were astonishing as 6 out of 8 pesticides were detected in water samples with alarming concentrations of Carbofuran (23.1µg/l) and Monocrotophos (8.3µg/l) which can be fatal for animals and humans in prolonged usage. The use of pesticides in a preventive and sustainable way gives more protection against pests and minimizes pollution such as water pollution or air pollution, etc., caused by the chemicals (pesticides). Hence such sustainable practices must be adopted for better production and conservation of the environment.

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Carvalho, Maiara A., Simone C. Marques, Emerson T. Martos, Renê LO Rigitano i Eustáquio S. Dias. "Bioaccumulation of insecticide in Agaricus subrufescens". Horticultura Brasileira 32, nr 2 (czerwiec 2014): 159–62. http://dx.doi.org/10.1590/s0102-05362014000200006.

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Agaricus subrufescens, known as Sun Mushroom, is a high-value mushroom because of its medicinal properties, used as nutraceutical food to stimulate the immune system and to prevent some diseases, including cancer. Mushrooms are generally characterized by their great ability to bioaccumulate heavy metals and other toxic substances from the mushroom compost. Sugarcane bagasse is a common raw material used in mushroom compost production for Agaricus subrufescenscultivation, whereas insecticides, such as fipronil, can be applied to combat several pests in sugarcane crops. For this reason, we aimed to assess mushroom yield and fipronil bioaccumulation in Sun Mushroom, regarding different concentrations added to the mushroom compost (0, 8, 16 and 32 mg kg-1) and casing layer (0, 2, 4 and 8 mg kg-1). Each experiment was arranged in a completely randomized design with four replicates. Regression analysis from mushroom production data was applied using SISVAR 5.1 program. Fipronil was quantified using gas-liquid chromatography (HP 6890) with thermionic detector (NPD). Mushroom yield was affected when fipronil was added, decreasing from 12% (compost with 0 mg kg-1 of fipronil) to 4.8% (compost with 32 mg kg-1). However, bioaccumulation was not detected. In contrast, insecticide bioaccumulation was detected when adding fipronil to casing layer, increasing from <0.01 mg kg-1 (casing layer with 2 mg kg-1) to 0.26 mg kg-1 (casing layer with 8 mg kg-1), however, mushroom yield was not affected.

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Baj, Jacek, Grzegorz Buszewicz, Dominika Przygodzka, Alicja Forma, Jolanta Flieger i Grzegorz Teresiński. "Diffusion of Carbon Monoxide and Hydrogen Cyanide to Muscles and Blood—An Experimental Study". Toxics 10, nr 11 (18.11.2022): 707. http://dx.doi.org/10.3390/toxics10110707.

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Postmortem carbon monoxide (CO) and hydrogen cyanide (HCN) diffusion under ambient conditions was assessed in a human cadaver model. The main objective of this study was to determine whether the postmortem diffusion of HCN and CO greatly affected the determination of HCN, carboxyhemoglobin (COHb), and carboxymyoglobin (COMb). Layered samples of blood, musculocutaneous, and muscular specimens were collected from the adult cadavers and placed in the tight chambers designed for the purpose of this experiment. The specimens were treated with CO and HCN for 24 h. COHb and COMb were determined using headspace gas chromatography (GC) with an O-FID detector while the HCN values were assessed using a GC headspace with an NPD detector. It was shown that the skin substantially limited the diffusion of CO which penetrated the superficial layers of the muscle very slightly, all the while not affecting the blood level of COHb in the 4.5 cm layer of the muscle located underneath. There were no differences regarding the CO diffusion between superficially charred and thermally coagulated compared to that observed in intact integuments. In addition, the cutaneous sample deprived of the adipose layer was not shown to be a barrier to the moderate diffusion of CO into the blood layer below. HCN was found to easily diffuse from the skin to the blood vessels (vein specimens), and partial charring and thermocoagulation of the superficial muscular layer favored the diffusion of cyanides into the tissues. Similarly to CO, HCN diffusion to the blood and muscles was greatly limited by the adipose layer.

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Medici, Emília P., Renata Carolina Fernandes-Santos, Caroline Testa-José, Antonio Francisco Godinho i Anne-Fleur Brand. "Lowland tapir exposure to pesticides and metals in the Brazilian Cerrado". Wildlife Research 48, nr 5 (2021): 393. http://dx.doi.org/10.1071/wr19183.

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Abstract ContextThe Cerrado is a Global Biodiversity Hotspot as well as Brazil’s main frontier for large-scale agriculture and livestock production, making it one of the most threatened biomes in the country. Brazil is one of the biggest consumers of pesticides in the world and allows the use of chemicals that are banned in many other countries due to their adverse health effects in a wide range of species, including humans. AimsThis study aimed to assess pesticide and metal exposure of the lowland tapir – a threatened, large herbivorous mammal – to support future studies of the role of these chemicals in tapir health, survivorship, and population viability. MethodsFoot pad, proboscis, stomach contents, liver, bone, and nail samples were obtained from tapir carcasses found along highways (n=87). (i) Atomic absorption spectrophotometry (AAS) was used to detect metals in bone, nail and liver tissue; (ii) gas chromatography – nitrogen phosphorous detector (GC-NPD) to detect organophosphates in liver and skin; and (iii) high performance liquid chromatography – ultraviolet (HPLC-UV) to detect pyrethroids and carbamates in stomach contents. Key resultsTwo carbamates (aldicarb and carbaryl), three organophosphates (diazinon, malathion, and mevinphos), two pyrethroids (deltamethrin and permethrin), and two toxic metals (cadmium and lead) were detected in different tapir tissue samples, some at concentrations high enough to cause adverse health effects. In 90% of roadkill tapirs that were subjected to a full post-mortem examination (n=25), macroscopic alterations of liver and/or kidney tissue were observed. ConclusionsThis study provides the first report to date of the detection of pesticides and metals in lowland tapirs. ImplicationsSome of the reported pesticide concentrations exceed environmental safety thresholds. Consequently, results from this study raise concerns over potential adverse health effects in tapirs that could lead to population level impacts, thus requiring further investigation.

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Saka, Kanju, Keiko Kudo, Akira Namera, Yusuke Fujii, Kanako Noritake, Suguru Torimitsu, Yohsuke Makino i Hirotaro Iwase. "Simple and simultaneous quantification of cyanide, ethanol, and 1-propanol in blood by headspace GC–MS/NPD with Deans switch dual detector system". Science & Justice 62, nr 2 (marzec 2022): 193–202. http://dx.doi.org/10.1016/j.scijus.2022.02.001.

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Li, P., M. Wu i J. Xie. "Changes in Levels of Amino Acids and Basic Components in Burley Tobacco Produced by Roasting". Beiträge zur Tabakforschung International/Contributions to Tobacco Research 20, nr 7 (1.11.2003): 459–66. http://dx.doi.org/10.2478/cttr-2013-0761.

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AbstractThree burley tobacco samples from three different areas in China and Brazil were roasted under three processing conditions. The amino acids and basic components of the burley tobacco samples were determined before and after roasting. Routine tobacco variables (reducing sugars, total water-soluble sugars, total nitrogen, total alkaloids, total volatile bases, and pH) were determined according to the Chinese National Standard Methods (CNSM). Free amino acids were determined by high performance liquid chromatography (HPLC). The basic compounds were isolated by use of simultaneous distillation and extraction (SDE) equipment. Their levels were determined qualitatively and quantitatively on a) a gas chromatograph (GC) equipped with a nitrogen-phosphorus detector (NPD) and b) by gas chromatography mass spectrometry (GC-MS). The results indicated that the chemical changes occurring during roasting have a significant impact on burley tobacco quality. Roasting decreased the tobacco pH value and the levels of total nitrogen, reducing sugars, free amino acids, and other nitrogenous substances, such as amines and alkaloids. The latter are usually related to the irritancy and sharp taste of burley tobacco smoke. In contrast, the levels of pyrazines, important contributors to the characteristic burley flavor, increased.

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Monsalve-Salamanca, Luz Adriana, María Martha Ortiz-Rangel i Alexis Mateus-Fontecha. "Identificación simultánea y determinación cualitativa de ácido cianhídrico y fosfina por cromatografía de gases con detector de nitrógeno fósforo y automuestreador Headspace (hs-gc-npd) en fluidos biológicos". Colombia Forense 2, nr 1 (15.12.2015): 19. http://dx.doi.org/10.16925/cf.v3i1.1188.

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Introducción: en el presente artículo se describe una metodología sensible, rápida y sencilla para la identificación y determinación cualitativa de fosfina y ácido cianhídrico, en muestras biológicas (i.e., sangre y contenido gástrico) y no biológicas por cromatografía de gases (gc). Metodología: lo anterior se llevó a cabo por medio de un detector selectivo de nitrógeno-fósforo (npd) y automuestreador de volátiles Headspace (hs), empleando acetonitrilo (acn) como estándar interno (istd). El procedimiento consiste en tomar y servir en un vial 1mL de la muestra a la cual se le adiciona ácido sulfúrico; el vial se sella herméticamente y se somete a incubación a 70 °C por 5 minutos. Finalmente, se inyecta 1 mL de fase gaseosa al cromatógrafo de gases. Resultados: los límites de detección y cuantificación hallados, tanto para la fosfina, como para el ácido cianhídrico, fueron 0,04 mg/L y 0,2 mg/L, respectivamente. Conclusiones: se implementó y se validó un método cromatográfico que permite la identificación simultánea y la determinación cualitativa de ácido cianhídrico y fosfina en muestras biológicas como sangre y contenido gástrico.

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Ramírez-Vásquez, Nicolás, María E. Betancur, Jhon D. Ruiz, Carlos López, Luis F. Restrepo i Mauren Zapata. "Validación de un método analítico para la determinación de Fention en leche bovina". Actualidades Biológicas 28, nr 85 (26.10.2017): 115–24. http://dx.doi.org/10.17533/udea.acbi.329392.

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Se realizó la validación de un método para la extracción y cuantificación del organofosforado fention en leche bovina. La medición se hizo por cromatografía de gases con detector de nitrógeno y fósforo (NPD). Con respecto a la validación del método se puede decir lo siguiente: el método analítico presentó selectividad para el organofosforado fenitrotion utilizado como estándar interno y para el analito de interés, fention. En lo concerniente a la precisión se observó que el coeficiente de variación en los resultados procedentes de tres inyecciones de los estándares de concentraciones de 0,025, 0,0625, 0,125, 0,1875, y 0,25 ppm fue menor del 5%. Los porcentajes de recuperación estuvieron entre el 92,8 y el 116% con un coeficiente de variación que fluctuó entre el 1,28 y el 6,62%. El límite de cuantificación fue de 0,025 ppm de fention. Con respecto a la linealidad del método el análisis de regresión lineal para la relación entre el cociente ·rea fention/·rea fenitrotion (variable dependiente) y el cociente concentración de fention/concentración de fenitrotion (variable independiente) arrojó un coeficiente de correlación de 0,9996% y un R2 de 99,92. El método analítico validado, es una técnica confiable para la determinación del fention en leche bovina y puede ser de gran aporte en el establecimiento de controles técnicos para la detección de residuos de organofosforados en leche para la industria láctea nacional.

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Panchenko, T., i L. Cherviakova. "Improvement of analytical determination of cyproconazole and propiconazole in fruit crops". Interdepartmental Thematic Scientific Collection of Plant Protection and Quarantine, nr 68 (20.04.2023): 208–15. http://dx.doi.org/10.36495/1606-9773.2022.68.208-215.

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Goal. Development and unification of the method of simultaneous determination of cyproconazole and propiconazole in fruits (apples, peaches, grapes) by gas-liquid chromatography (GC). Methods. The active substances were determined by gas-liquid chromatography (GC) using a gas chromatograph «Perkin Elmer 8410» with an NPD detector. Propiconazole and cyproconazole were identified by the retention time of the compounds, quantification by the calibration dependence of the chromatographic peak area of the analyte on its concentration in the calibration solution by correlation and regression analyzes. Results. The choice of the method of determination is limited by the physicochemical properties of the active substance and the characteristics of the object under study (matrix). The optimal conditions for determination were selected using a chemical-analytical monitoring algorithm and a system for multiquantitative determination of pesticides in matrices. According to them, the matrices are analyzed in stages: extraction, purification, qualitative and quantitative determination. Cyproconazole and propiconazole are low-polar compounds (µ of their cis- and trans-isomers are 4.43; 4.71 and 3.80; 4.20 D, respectively), so extraction was performed with chloroform (ε 5.1). Purification of extracts from coextractive substances of matrices was performed by TLC. Compounds were identified by retention time, and quantification (C, µg/ml) was performed on the areas of chromatographic peaks (S, mm2) in the range of linear detection (2—10 ng) according to the linear regression equations: Sc = 11.991 C — 6.096 (R2 = 0.998); Sp = 13.721 C – 4.221 (R2 = 0,994). The average value of measurement is 81.0—87.8%; standard deviation 2.21—5.38%; confidence interval (P 0.95; n = 15) 1.94—4.72%. Conclusions. Optimal selective conditions for the analysis of triazole derivatives by chromatographic methods provide simultaneous determination of test compounds and quality control of fruit crops on the content of residual amounts of cyproconazole and propiconazole at the level of hygienic standards (MAL 0.05—0.10 mg/kg).

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Arteaga palomo, Gregorio De Jesús, Jose Luís Marrugo Negrete i Juan Gabriel Sanchez Castellón. "Plaguicidas en canales de riego del distrito de La Doctrina (Córdoba-Colombia)". Temas Agrarios 23, nr 1 (19.12.2017): 20–36. http://dx.doi.org/10.21897/rta.v23i1.1143.

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El distrito de La Doctrina-Córdoba, aporta a la economía colombiana, con cultivos de arroz (1.230 ha), maíz (50ha), palma africana (300 ha), papaya (10 ha), hortalizas (8 ha) y 400 ha de pastos. Estos cultivos utilizan plaguicidas ocasionando contaminación en los canalesde riego, dichas aguas son utilizadas por los pobladores para uso doméstico y consumo humano. El objetivo de esta investigación fue evaluar las concentraciones de plaguicidas organoclorados (POCls), organofosforados (POFs) y cipermetrina (CP) en aguas de los canales de riego del distrito de La Doctrina en dos épocas del año (seca y lluviosa). Los análisis fueron realizados por Cromatografía de gases y Gases-Masas. La CP se detectó por monitoreo de masas SIM, los POCls y POFs se analizaron con detector de captura de electrones (ECD) y nitrógeno-fosforo (NPD) respectivamente. Los resultados mostraron que todas las concentraciones de CP (época-seca) están por encima del límite aceptado según la norma colombiana para agua potable, según la norma Argentina todos sobrepasan los límites permisibles. Entre los POCls solo el Endrín sobrepasó la norma colombiana, no se encontraron POFs. Los porcentajes de aparición individual de plaguicidas muestran el valor más alto para cipermetrina con un 73%. Las altas concentraciones de CP y POCls, en el agua de riego en el distrito La Doctrina, generan un alto interés por la detección de las concentraciones de estos contaminantes es alimentos como el arroz y un alto riesgo a la salud humana.

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Linkerh�gner, Manfred, i Hans J�rgen Stan. "Screening analysis of pesticide residues in plant foodstuffs by capillary gas chromatography using the DFG multiresidue method S19: a comparison of customory detection by ECD/NPD with the novel atomic emission detector (AED)". Zeitschrift f�r Lebensmittel-Untersuchung und -Forschung 198, nr 6 (czerwiec 1994): 473–79. http://dx.doi.org/10.1007/bf01192843.

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Machado, Carolina Sampaio, Brisa Maria Fregonesi, Guilherme Sgobbi Zagui, Bruno Spinosa de Martinis i Susana Segura Muñoz. "ATRAZINA NA ÁGUA FLUVIAL: AVALIAÇÃO DE RISCO À SAÚDE HUMANA PELA EXPOSIÇÃO RECREACIONAL". Revista Gestão & Sustentabilidade Ambiental 7, nr 3 (3.10.2018): 36. http://dx.doi.org/10.19177/rgsa.v7e3201836-46.

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Herbicidas nas águas dos rios podem resultar em relevantes riscos à saúde humana das comunidades adjacentes. As populações podem ser expostas a poluição dos rios pela ingestão de água durante atividades recreativas. O objetivo do presente trabalho foi avaliar os riscos à saúde humana associados à exposição ao herbicida Atrazina durante atividades recreacionais no Rio Pardo, Brasil. O Rio Pardo é o maior tributário na margem esquerda do Rio Grande, com cerca de 550 km de extensão. A bacia de drenagem é de cerca de 10.694 km2, abrangendo mas de um milhão de habitantes. Quatro campanhas de coleta de dados foram realizadas (duas na estação seca e duas na estação chuvosa) e duplicatas das amostras de água foram coletadas em cinco pontos de coleta ao longo do Rio Pardo. Todos os pontos de coleta estavam localizados próximos a culturas de cana-de-açúcar. Atrazina foi extraída das amostras de água do rio por extração em fase sólida utilizado discos C18 e a quantificação foi conduzida por Cromatografia a Gás acoplada com detector de nitrogênio e fósforo-GC/NPD. Atrazina foi detectada em quarto dos cinco pontos de coleta (variando de: 0,16-0,32 µg/L) abaixo dos limites estabelecidos pela legislação brasileira (2,0 µg/L), mas acima dos níveis permitidos pela União Europeia (0,1 µg/L). Riscos à saúde humana foram calculados de acordo com a metodologia da agência ambiental Norte-Americana (USEPA). Os riscos não-carcinogênicos pela exposição à Atrazina durante atividades de recreação estiveram abaixo dos limites (Hazard Quotient<1), assim como os riscos carcinogênicos (<10-6), não representando risco à saúde pública. A Atrazina é amplamente utilizada nas culturas de cana-de-açúcar e os riscos à saúde humana, associados às misturas de herbicidas em rios utilizados para atividades recreacionais, como o Rio Pardo, são importantes no contexto da toxicologia e da Saúde Pública.

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Brondz, Ilia. "High-Performance Liquid Chromatograph (HPLC) Equipped with a Neurophysiological Detector (NPD) as a Tool for Studying Olfactory System Intoxication by the Organophosphate (OP) Pesticide Diazinon and the Influence of OP Pesticides on Reproduction". International Journal of Analytical Mass Spectrometry and Chromatography 03, nr 01 (2015): 14–24. http://dx.doi.org/10.4236/ijamsc.2015.31002.

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Bisschops, Raf, Jonathan Manning, Lucy Clayton, Richard Ng Kwet Shing i Marco Álvarez-González. "Colon cleansing efficacy and safety with 1 L NER1006 versus 2 L polyethylene glycol + ascorbate: a randomized phase 3 trial". Endoscopy 51, nr 01 (19.07.2018): 60–72. http://dx.doi.org/10.1055/a-0638-8125.

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Abstract Background Polyethylene glycol (PEG)-based bowel preparations are effective cleansers but many require high-volume intake. This phase 3, randomized, blinded, multicenter, parallel-group, central reader-assessed study assessed the 1 L PEG NER1006 bowel preparation vs. standard 2 L PEG with ascorbate (2LPEG). Methods Patients undergoing colonoscopy were randomized (1:1:1) to receive NER1006, as an evening/morning (N2D) or morning-only (N1D) regimen, or evening/morning 2LPEG. Cleansing was assessed using the Harefield Cleansing Scale (HCS) and the Boston Bowel Preparation Scale (BBPS). Primary end points were overall bowel cleansing success and high-quality cleansing in the right colon. Modified full analysis set (mFAS) and per protocol (PP) analyses were performed. Mean cleansing scores were analyzed post hoc. Results Of 849 randomized patients, efficacy was analyzed in the following patient numbers (mFAS/PP): total n = 822/670; N2D n = 275/220; N1D n = 275/218; 2LPEG n = 272/232. mFAS established noninferiority. PP showed superiority for N2D on overall success (97.3 % vs. 92.2 %; P = 0.014), and for N2D and N1D on right colon high-quality cleansing (N2D 32.3 % vs. 15.9 %, P < 0.001; N1D 34.4 % vs. 15.9 %, P < 0.001) vs. 2LPEG. Using HCS, N2D and N1D attained superior segmental high-quality cleansing (P ≤ 0.003 per segment). N2D showed superior mean segmental HCS scores (P ≤ 0.007 per segment). Both N2D and N1D achieved superior mean overall (P < 0.001 and P = 0.006) and right colon BBPS scores (P < 0.001 and P = 0.013). N2D demonstrated superior right colon polyp detection (P = 0.024). Adherence, tolerability, and safety were comparable between treatments. Conclusions NER1006 is the first low-volume preparation to demonstrate superior colon cleansing efficacy vs. standard 2LPEG with ascorbate, with comparable safety and tolerability. European Clinical Trials Database (EudraCT)2014-002185-78TRIAL REGISTRATION: Multicenter, randomized, parallel group, phase 3 trial 2014-002185-78 at https://eudract.ema.europa.eu/

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Lin, C. R., D. H. Wei, M. K. BenDao, W. E. Chen i T. Y. Liu. "Development of High-Performance UV Detector Using Nanocrystalline Diamond Thin Film". International Journal of Photoenergy 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/492152.

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Nanocrystalline diamond (NCD) films are promising materials for wide-spread applications due to their outstanding characteristics of chemical, physical, and highly smooth surface. Our present work aimed at the fabrication of high performance diamond-based UV detector. NCD films were prepared by microwave plasma enhanced chemical vapor deposition process, and then Au interdigital electrodes were deposited onto the surface of the as-grown NCD film by sputtering technique. Annealing procedures were conducted at various temperatures to obtain Ohmic contact of NCD/Au structure. The surface morphology, microstructure, and wettablity of the NCD films were analyzed by scanning electron microscopy, atomic forced microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and water contact angle measurement, respectively. The electrical property and photoconductivity of the fabricated devices were tested for UV detection application. It was found that the NCD films possessed high sp3fraction of 68.6%, low surface roughness of 9.6 nm, and good hydrophobicity, as deposited under working pressure of 40 Torr. Also, the NCD/Au structure annealed at 500°C exhibited a good Ohmic contact characteristic, high detection efficiency, and fast response to UV irradiation in air ambient. The proposed study indeed demonstrates prospective applications of NCD films in UV detector, photocatalyst, solar cell, and so on.

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Levran, O., RJ Desnick i EH Schuchman. "Identification and expression of a common missense mutation (L302P) in the acid sphingomyelinase gene of Ashkenazi Jewish type A Niemann-Pick disease patients". Blood 80, nr 8 (15.10.1992): 2081–87. http://dx.doi.org/10.1182/blood.v80.8.2081.bloodjournal8082081.

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Types A and B Niemann-Pick disease (NPD) result from the deficient activity of acid sphingomyelinase (ASM; E.C. 3.1.4.12) and the resultant lysosomal accumulation of sphingomyelin. Type A disease is a fatal, neurodegenerative disorder of infancy, whereas type B disease has no neurologic manifestations and is characterized primarily by reticuloendothelial involvement and survival into adulthood. Both disorders occur more frequently among individuals of Ashkenazi Jewish ancestry than in the general population. Recently, a missense mutation in the ASM gene (designated R496L) was detected in more than 30% of the ASM alleles from Ashkenazi Jewish type A NPD patients. We report a second, common mutation that resulted from a T to C transition at nucleotide 905 and predicted a leucine to proline substitution at ASM codon 302 (designated L302P). Notably, the L302P mutation occurred in 23.5% (8 of 34) of the Ashkenazi Jewish type A NPD alleles studied. In contrast, it was not found in any of the ASM alleles from non-Jewish type A patients, in 36 alleles from type B patients, or in 100 ASM alleles from normal Ashkenazi Jewish individuals. To confirm the authenticities of the L302P and R496L mutations, each nucleotide change was separately introduced into the full-length ASM cDNA by site- directed mutagenesis and transiently expressed in COS-1 cells. Neither mutation expressed ASM catalytic activity, consistent with the type A phenotype of homoallelic patients. The identification of the L302P mutation should further facilitate molecular carrier detection for NPD in the Ashkenazi Jewish population, particularly because the L302P mutation can be easily detected using the restriction enzyme, AlwNl.

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Breen, Leanne T., Lisa M. Smyth, Ilia A. Yamboliev i Violeta N. Mutafova-Yambolieva. "β-NAD is a novel nucleotide released on stimulation of nerve terminals in human urinary bladder detrusor muscle". American Journal of Physiology-Renal Physiology 290, nr 2 (luty 2006): F486—F495. http://dx.doi.org/10.1152/ajprenal.00314.2005.

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Endogenous nucleotides with extracellular functions may be involved in the complex neural control of human urinary bladder (HUB). Using HPLC techniques with fluorescence detection, we observed that in addition to ATP and its metabolites ADP, AMP and adenosine, electrical field stimulation (EFS; 4–16 Hz, 0.1 ms, 15 V, 60 s) of HUB detrusor smooth muscle coreleases novel nucleotide factors, which produce etheno-1 N6-ADP-ribose (eADPR) on etheno-derivatization at high temperature. A detailed HPLC fraction analysis determined that nicotinamide adenine dinucleotide (β-NAD+; 7.0 ± 0.7 fmol/mg tissue) is the primary nucleotide that contributes to the formation of eADPR. The tissue superfusates collected during EFS also contained the β-NAD+ metabolite ADPR (0.35 ± 0.2 fmol/mg tissue) but not cyclic ADPR (cADPR). HUB failed to degrade nicotinamide guanine dinucleotide (NGD+), a specific substrate of ADP ribosyl cyclase, suggesting that the activity of this enzyme in the HUB is negligible. The EFS-evoked release of β-NAD+ was frequency dependent and is reduced in the presence of tetrodotoxin (TTX; 0.3 μmol/l), ω-conotoxin GVIA (50 nmol/l), and botulinum neurotoxin A (BoNT/A; 100 nmol/l), but remained unchanged in the presence of guanethidine (3 μmol/l), ω-agatoxin IVA (50 nmol/l), or charbachol (1 μmol/l). Capsaicin (10 μmol/l) increased both the resting and EFS-evoked overflow of β-NAD+. Exogenous β-NAD+ (1 μmol/l) reduced both the frequency and amplitude of spontaneous contractions. In conclusion, we detected nerve-evoked overflow of β-NAD+ and ADPR in HUB. The β-NAD+/ADPR system may constitute a novel inhibitory extracellular nucleotide mechanism of neural control of the human bladder.

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Levran, O., RJ Desnick i EH Schuchman. "Identification and expression of a common missense mutation (L302P) in the acid sphingomyelinase gene of Ashkenazi Jewish type A Niemann-Pick disease patients". Blood 80, nr 8 (15.10.1992): 2081–87. http://dx.doi.org/10.1182/blood.v80.8.2081.2081.

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Abstract Types A and B Niemann-Pick disease (NPD) result from the deficient activity of acid sphingomyelinase (ASM; E.C. 3.1.4.12) and the resultant lysosomal accumulation of sphingomyelin. Type A disease is a fatal, neurodegenerative disorder of infancy, whereas type B disease has no neurologic manifestations and is characterized primarily by reticuloendothelial involvement and survival into adulthood. Both disorders occur more frequently among individuals of Ashkenazi Jewish ancestry than in the general population. Recently, a missense mutation in the ASM gene (designated R496L) was detected in more than 30% of the ASM alleles from Ashkenazi Jewish type A NPD patients. We report a second, common mutation that resulted from a T to C transition at nucleotide 905 and predicted a leucine to proline substitution at ASM codon 302 (designated L302P). Notably, the L302P mutation occurred in 23.5% (8 of 34) of the Ashkenazi Jewish type A NPD alleles studied. In contrast, it was not found in any of the ASM alleles from non-Jewish type A patients, in 36 alleles from type B patients, or in 100 ASM alleles from normal Ashkenazi Jewish individuals. To confirm the authenticities of the L302P and R496L mutations, each nucleotide change was separately introduced into the full-length ASM cDNA by site- directed mutagenesis and transiently expressed in COS-1 cells. Neither mutation expressed ASM catalytic activity, consistent with the type A phenotype of homoallelic patients. The identification of the L302P mutation should further facilitate molecular carrier detection for NPD in the Ashkenazi Jewish population, particularly because the L302P mutation can be easily detected using the restriction enzyme, AlwNl.

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Yudov, Alexei Alexandrovich, Sokolov Yu A. Sokolov i Yuri Illarionovich Chernukhin. "Nitrogenous Explosives Detection by NeutronRadiation Method Using Gamma Radiation Heterogeneous Scintillation Detector". Izvestiya Wysshikh Uchebnykh Zawedeniy, Yadernaya Energetika 2013, nr 1 (maj 2013): 125–32. http://dx.doi.org/10.26583/npe.2013.1.16.

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Yalçın Dokumacı, Keziban, i Cengiz Özarslan. "Comparison of Some Spraying Characteristics by Testing Different Spray Nozzle Positions on Artificial Cotton Plants when Defoliant Application". Turkish Journal of Agriculture - Food Science and Technology 11, nr 4 (26.04.2023): 785–90. http://dx.doi.org/10.24925/turjaf.v11i4.785-790.5948.

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In this study, limit application rates and different spray nozzle positions effects on coverage rate, drop diameter and amount of tracer residue values were determined of application defoliating agent before machine harvest on cotton plant. Researches were carried on two phases as indoor area trials and laboratory analysis. In these researches, artificial cotton plants were used. Indoor area trials were conducted two different application rates (20 and 40 L da-1) and three different in spray nozzle positions (NP1, NP2 and NP3) by using conventional hollow cone spray nozzle. 27 pieces of sampling area were determined that they were included the two sides of the plant and plant center position of the upper-middle-lower in initiative area on plants. Six initiative areas were determined in order to record efficiency in initiative area on plants. For the purpose of deposition of trace amounts of substances were determined in sampling area; water-sensitive paper is placed on top that included both over the leaves and beneath the leaves in order to detect each filter paper, and drop diameter, rate of coverage. The amount of deposit on areas that were done analysis in laboratory conditions was determined to with spectrophotometer. Drop diameters and coverage rate detection were done analysis on image analysis. According to the results, it is determined that NP3 which is used generally in 40 L da-1 norm provide the best deposition and coverage rate on applications of defoliant, in addition to pesticide reach on leaf beneath in merely this spray nozzle position.

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Prystajecky, Natalie, Peter M. Huck, Hans Schreier i Judith L. Isaac-Renton. "Assessment of Giardia and Cryptosporidium spp. as a Microbial Source Tracking Tool for Surface Water: Application in a Mixed-Use Watershed". Applied and Environmental Microbiology 80, nr 8 (24.01.2014): 2328–36. http://dx.doi.org/10.1128/aem.02037-13.

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ABSTRACTKnowledge of host specificity, combined with genomic sequencing ofGiardiaandCryptosporidiumspp., has demonstrated a microbial source tracking (MST) utility for these common waterborne microbes. To explore the source attribution potential of these pathogens, water samples were collected in a mixed rural-urban watershed in the Township of Langley, in southwestern British Columbia (BC), Canada, over a 2-year period.Cryptosporidiumwas detected in 63% of surface water samples at concentrations ranging from no positive detection (NPD) to 20,600 oocysts per 100 liters.Giardiawas detected in 86% of surface water samples at concentrations ranging from NPD to 3,800 cysts per 100 liters of water. Sequencing at the 18S rRNA locus revealed that 50% ofCryptosporidiumsamples and 98% ofGiardiasamples contained species/genotypes (Cryptosporidium) or assemblages (Giardia) that are capable of infecting humans, based on current knowledge of host specificity and taxonomy.Cryptosporidiumgenotyping data were more promising for source tracking potential, due to the greater number of host-adapted (i.e., narrow-host-range) species/genotypes compared toGiardia, since 98% ofGiardiaisolates were zoonotic and the potential host could not be predicted. This report highlights the benefits of parasite genomic sequencing to complement Method 1623 (U.S. Environmental Protection Agency) and shows thatCryptosporidiumsubtyping for MST purposes is superior to the use ofGiardiasubtyping, based on better detection limits forCryptosporidium-positive samples than forGiardia-positive samples and on greater host specificity amongCryptosporidiumspecies. These additional tools could be used for risk assessment in public health and watershed management decisions.

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Dao Thi, Hang, Marko R. Djokic i Kevin M. Van Geem. "Detailed Group-Type Characterization of Plastic-Waste Pyrolysis Oils: By Comprehensive Two-Dimensional Gas Chromatography Including Linear, Branched, and Di-Olefins". Separations 8, nr 7 (16.07.2021): 103. http://dx.doi.org/10.3390/separations8070103.

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Plastic-waste pyrolysis oils contain large amounts of linear, branched, and di-olefinic compounds. This makes it not obvious to determine the detailed group-type composition in particular to the presence of substantial amounts of N-, S-, and O-containing heteroatomic compounds. The thorough evaluation of different column combinations for two-dimensional gas chromatography (GC × GC), i.e., non-polar × polar and polar × non-polar, revealed that the second combination had the best performance, as indicated by the bi-dimensional resolution of the selected key compounds. By coupling the GC × GC to multiple detectors, such as the flame ionization detector (FID), a sulfur chemiluminescence detector (SCD), a nitrogen chemiluminescence detector (NCD), and a mass spectrometer (MS), the identification and quantification were possible of hydrocarbon, oxygen-, sulfur-, and nitrogen-containing compounds in both naphtha (C5–C11) and diesel fractions (C7–C23) originating from plastic-waste pyrolysis oils. Group-type quantification showed that large amounts of α-olefins (36.39 wt%, 35.08 wt%), iso-olefins (8.77 wt%, 9.06 wt%), and diolefins (4.21 wt%, 4.20 wt%) were present. Furthermore, oxygen-containing compounds (alcohols, ketones, and ethers) could be distinguished from abundant hydrocarbon matrix, by employing Stabilwax as the first column and Rxi-5ms as the second column. Ppm levels of sulfides, thiophenes, and pyridines could also be quantified by the use of selective SCD and NCD detectors.

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Freije-Carrelo, Laura, Javier García-Bellido, Laura Alonso Sobrado, Mariella Moldovan, Brice Bouyssiere, Pierre Giusti i Jorge Ruiz Encinar. "Quantitative multiplexed elemental (C, H, N and S) detection in complex mixtures using gas chromatography". Chemical Communications 56, nr 19 (2020): 2905–8. http://dx.doi.org/10.1039/c9cc09842a.

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Capabilities of well-established GC detectors (FID, NCD, SCD, MSD) are integrated in one single instrumental set-up able to provide simultaneous universal and H-, N- and S-element selective detection, equimolar response and structural elucidation.

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Dempsey, Laurie A. "Facilitating Nod detection". Nature Immunology 15, nr 5 (18.04.2014): 414. http://dx.doi.org/10.1038/ni.2883.

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Wang, Yi, Boya Fu, Longwen Fu i Chunlei Xia. "In Situ Sea Cucumber Detection across Multiple Underwater Scenes Based on Convolutional Neural Networks and Image Enhancements". Sensors 23, nr 4 (10.02.2023): 2037. http://dx.doi.org/10.3390/s23042037.

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Recently, rapidly developing artificial intelligence and computer vision techniques have provided technical solutions to promote production efficiency and reduce labor costs in aquaculture and marine resource surveys. Traditional manual surveys are being replaced by advanced intelligent technologies. However, underwater object detection and recognition are suffering from the image distortion and degradation issues. In this work, automatic monitoring of sea cucumber in natural conditions is implemented based on a state-of-the-art object detector, YOLOv7. To depress the image distortion and degradation issues, image enhancement methods are adopted to improve the accuracy and stability of sea cucumber detection across multiple underwater scenes. Five well-known image enhancement methods are employed to improve the detection performance of sea cucumber by YOLOv7 and YOLOv5. The effectiveness of these image enhancement methods is evaluated by experiments. Non-local image dehazing (NLD) was the most effective in sea cucumber detection from multiple underwater scenes for both YOLOv7 and YOLOv5. The best average precision (AP) of sea cucumber detection was 0.940, achieved by YOLOv7 with NLD. With NLD enhancement, the APs of YOLOv7 and YOLOv5 were increased by 1.1% and 1.6%, respectively. The best AP was 2.8% higher than YOLOv5 without image enhancement. Moreover, the real-time ability of YOLOv7 was examined and its average prediction time was 4.3 ms. Experimental results demonstrated that the proposed method can be applied to marine organism surveying by underwater mobile platforms or automatic analysis of underwater videos.

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PERTIWI, NI PUTU DIAN, BUDI NUGRAHA, RIRIK KARTIKA SULISTYANINGSIH, IRWAN JATMIKO, ANDRIANUS SEMBIRING, ANGKA MAHARDINI, NI KADEK DITA CAHYANI i in. "Short Communication: Lack of differentiation within the bigeye tuna population of Indonesia". Biodiversitas Journal of Biological Diversity 18, nr 4 (4.10.2017): 1406–13. http://dx.doi.org/10.13057/biodiv/d180416.

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Pertiwi NPD, Nugraha B, Kartika R, Sulistyaningsih RK, Jatmiko I, Sembiring A, Mahardini A, Cahyani NKD, Anggoro AW, Madduppa HH, Ambariyanto A, Barber PH, Mahardika GN. 2017. Short Communication: Lack of differentiation within the bigeye tuna population of Indonesia. Biodiversitas 18: 1406-1413. All highly migratory tuna and tuna-like species have vast feeding grounds and spawning grounds. Indonesiaâ€™s tuna catch is the largest in the world. However, genetic diversity in the population structure within particular tuna species in Indonesia is very limited. Here we provide genetic data for bigeye tuna (Thunnus obesus) covering fishing grounds and local fish markets throughout Indonesia. A fragment of mitochondrial DNA in the D-loop control region was amplified from samples collected across Indonesia in the biennium 2012-2013. The results showed high haplotype diversity and low nucleotide diversity in our samples. Little differentiation occured between the eleven diverse sampling locations, nor was any separation detected between general regions of Indonesia, nor between samples from fishing grounds and samples from fish markets.

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Zhang, Daquan, i Zhiyong Fan. "(Invited, Digital Presentation) Vertical Heterogeneous Integration of Metal Halide Perovskite Quantum-Wires/Nanowires for Flexible Narrowband Photodetectors". ECS Meeting Abstracts MA2022-02, nr 36 (9.10.2022): 1340. http://dx.doi.org/10.1149/ma2022-02361340mtgabs.

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Charge collection narrowing (CCN) has been reported to be an efficient strategy to achieve optical filter-free narrowband photodetection (NPD) with metal halide perovskite (MHP) single crystals. However, the necessity of utilizing thick crystals in CCN limits their applications in large scale, flexible, self-driven, and high-performance optoelectronics. Here, for the first time, we fabricate vertically integrated MHP quantum wire/nanowire (QW/NW) array-based photodetectors in nanoengineered porous alumina membranes (PAMs) showing self-driven broadband photodetection (BPD) and NPD capability simultaneously. Two cutoff detection edges of the NPDs are located at around 770 and 730 nm, with a full-width at half-maxima (fwhm) of around 40 nm. The optical bandgap difference between the NWs and the QWs, in conjunction with the high carrier recombination rate in QWs, contributes to the intriguing NPD performance. Thanks to the excellent mechanical flexibility of the PAMs, a flexible NPD is demonstrated with respectable performance. Our work here opens a new pathway to design and engineer a nanostructured MHP for novel color selective and full color sensing devices. Figure 1

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