scholarly journals Retrieval of Phytoplankton Pigments from Underway Spectrophotometry in the Fram Strait

2019 ◽  
Vol 11 (3) ◽  
pp. 318 ◽  
Author(s):  
Yangyang Liu ◽  
Emmanuel Boss ◽  
Alison Chase ◽  
Hongyan Xi ◽  
Xiaodong Zhang ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Performance ◽  
Matrix Inversion ◽  
Percentage Error ◽  
Fram Strait ◽  
Total Chlorophyll ◽  
Concentration Data ◽  
Inversion Technique ◽  
The Matrix ◽  
Gaussian Decomposition

Phytoplankton in the ocean are extremely diverse. The abundance of various intracellular pigments are often used to study phytoplankton physiology and ecology, and identify and quantify different phytoplankton groups. In this study, phytoplankton absorption spectra ( a p h ( λ ) ) derived from underway flow-through AC-S measurements in the Fram Strait are combined with phytoplankton pigment measurements analyzed by high-performance liquid chromatography (HPLC) to evaluate the retrieval of various pigment concentrations at high spatial resolution. The performances of two approaches, Gaussian decomposition and the matrix inversion technique are investigated and compared. Our study is the first to apply the matrix inversion technique to underway spectrophotometry data. We find that Gaussian decomposition provides good estimates (median absolute percentage error, MPE 21–34%) of total chlorophyll-a (TChl-a), total chlorophyll-b (TChl-b), the combination of chlorophyll-c1 and -c2 (Chl-c1/2), photoprotective (PPC) and photosynthetic carotenoids (PSC). This method outperformed one of the matrix inversion algorithms, i.e., singular value decomposition combined with non-negative least squares (SVD-NNLS), in retrieving TChl-b, Chl-c1/2, PSC, and PPC. However, SVD-NNLS enables robust retrievals of specific carotenoids (MPE 37–65%), i.e., fucoxanthin, diadinoxanthin and 19 ′ -hexanoyloxyfucoxanthin, which is currently not accomplished by Gaussian decomposition. More robust predictions are obtained using the Gaussian decomposition method when the observed a p h ( λ ) is normalized by the package effect index at 675 nm. The latter is determined as a function of “packaged” a p h ( 675 ) and TChl-a concentration, which shows potential for improving pigment retrieval accuracy by the combined use of a p h ( λ ) and TChl-a concentration data. To generate robust estimation statistics for the matrix inversion technique, we combine leave-one-out cross-validation with data perturbations. We find that both approaches provide useful information on pigment distributions, and hence, phytoplankton community composition indicators, at a spatial resolution much finer than that can be achieved with discrete samples.

Morphology of High-Performance Rigid-Rod Polymer Fibers and Molecular Composites

1989 ◽  
Vol 47 ◽  
pp. 338-339
Author(s):  
W.W. Adams ◽  
S. J. Krause
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Liquid Crystalline ◽  
Molecular Level ◽  
Synergistic Effects ◽  
Tensile Modulus ◽  
Commercial Development ◽  
The Matrix ◽  
Molecular Composites ◽  
Rigid Rod

Rigid-rod polymers such as PBO, poly(paraphenylene benzobisoxazole), Figure 1a, are now in commercial development for use as high-performance fibers and for reinforcement at the molecular level in molecular composites. Spinning of liquid crystalline polyphosphoric acid solutions of PBO, followed by washing, drying, and tension heat treatment produces fibers which have the following properties: density of 1.59 g/cm3; tensile strength of 820 kpsi; tensile modulus of 52 Mpsi; compressive strength of 50 kpsi; they are electrically insulating; they do not absorb moisture; and they are insensitive to radiation, including ultraviolet. Since the chain modulus of PBO is estimated to be 730 GPa, the high stiffness also affords the opportunity to reinforce a flexible coil polymer at the molecular level, in analogy to a chopped fiber reinforced composite. The objectives of the molecular composite concept are to eliminate the thermal expansion coefficient mismatch between the fiber and the matrix, as occurs in conventional composites, to eliminate the interface between the fiber and the matrix, and, hopefully, to obtain synergistic effects from the exceptional stiffness of the rigid-rod molecule. These expectations have been confirmed in the case of blending rigid-rod PBZT, poly(paraphenylene benzobisthiazole), Figure 1b, with stiff-chain ABPBI, poly 2,5(6) benzimidazole, Fig. 1c A film with 30% PBZT/70% ABPBI had tensile strength 190 kpsi and tensile modulus of 13 Mpsi when solution spun from a 3% methane sulfonic acid solution into a film. The modulus, as predicted by rule of mixtures, for a film with this composition and with planar isotropic orientation, should be 16 Mpsi. The experimental value is 80% of the theoretical value indicating that the concept of a molecular composite is valid.

scholarly journals Simplified and Rapid Determination of Primaquine and 5,6-Orthoquinone Primaquine by UHPLC-MS/MS: Its Application to a Pharmacokinetic Study

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4357
Author(s):  
Waritda Pookmanee ◽  
Siriwan Thongthip ◽  
Jeeranut Tankanitlert ◽  
Mathirut Mungthin ◽  
Chonlaphat Sukasem ◽  
...  
Keyword(s):  
Pharmacokinetic Study ◽  
High Performance ◽  
Rapid Determination ◽  
Active Metabolites ◽  
Chromatography Tandem Mass Spectrometry ◽  
Accuracy And Precision ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Isocratic Mode

The method for the determination of primaquine (PQ) and 5,6-orthoquinone primaquine (5,6-PQ), the representative marker for PQ active metabolites, via CYP2D6 in human plasma and urine has been validated. All samples were extracted using acetonitrile for protein precipitation and analyzed using the ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) system. Chromatography separation was carried out using a Hypersil GOLDTM aQ C18 column (100 × 2.1 mm, particle size 1.9 μm) with a C18 guard column (4 × 3 mm) flowed with an isocratic mode of methanol, water, and acetonitrile in an optimal ratio at 0.4 mL/min. The retention times of 5,6-PQ and PQ in plasma and urine were 0.8 and 1.6 min, respectively. The method was validated according to the guideline. The linearity of the analytes was in the range of 25–1500 ng/mL. The matrix effect of PQ and 5,6-PQ ranged from 100% to 116% and from 87% to 104% for plasma, and from 87% to 89% and from 86% to 87% for urine, respectively. The recovery of PQ and 5,6-PQ ranged from 78% to 95% and form 80% to 98% for plasma, and from 102% to from 112% to 97% to 109% for urine, respectively. The accuracy and precision of PQ and 5,6-PQ in plasma and urine were within the acceptance criteria. The samples should be kept in the freezer (−80 °C) and analyzed within 7 days due to the metabolite stability. This validated UHPLC-MS/MS method was beneficial for a pharmacokinetic study in subjects receiving PQ.

scholarly journals Development and Validation of a Sensitive, Specific and Reproducible UPLC-MS/MS Method for the Quantification of OJT007, A Novel Anti-Leishmanial Agent: Application to a Pharmacokinetic Study

2021 ◽  
Vol 18 (9) ◽  
pp. 4624
Author(s):  
Maria Rincon Nigro ◽  
Jing Ma ◽  
Ololade Tosin Awosemo ◽  
Huan Xie ◽  
Omonike Arike Olaleye ◽  
...  
Keyword(s):  
Formic Acid ◽  
High Performance ◽  
Leishmania Major ◽  
Internal Standard ◽  
Gradient Elution ◽  
Rat Plasma ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Positive Mode ◽  
Acquity Uplc

OJT007 is a methionine aminopeptidase 1 (MetAP1) inhibitor with potent anti-proliferative effects against Leishmania Major. In order to study its pharmacokinetics as a part of the drug development process, a sensitive, specific, and reproducible ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated. Voriconazole was used as the internal standard to generate standard curves ranging from 5 to 1000 ng/mL. The separation was achieved using a UPLC system equipped with an Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm) with 0.1% formic acid in acetonitrile and 0.1% formic acid in water as the mobile phase under gradient elution at a flow rate of 0.4 mL/min. The mass analysis was performed with a 4000 QTRAP® mass spectrometer using multiple-ion reaction monitoring (MRM) in the positive mode, with the transition of m/z 325 → m/z 205 for OJT007 and m/z 350 → m/z 101 for voriconazole. The intra- and inter-day precision and accuracy were within ±15%. The mean extraction recovery and the matrix effect were 95.1% and 7.96%, respectively, suggesting no significant matrix interfering with the quantification of the drug in rat plasma. This study was successfully used for the pharmacokinetic evaluation of OJT007 using the rat as an animal model.

scholarly journals Behaviour of UHPFRCs in compression under high stress-rates

2018 ◽  
Vol 183 ◽  
pp. 02005
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Behaviour ◽  
High Performance ◽  
High Stress ◽  
Slight Reduction ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Dynamic Event ◽  
The Matrix ◽  
High Performance Fibre

The paper presents the results obtained on cylindrical Ultra High Performance Fibre Reinforced Concrete specimens with diameter of 30mm and a height of 60mm under compression at high stress rate (1.7–2.3 TPa/s). Four different percentages of fibre reinforcement are considered (1, 2, 3, and 4% fibre content) and compared with the results of the matrix (UHPC). A slight reduction of the strength and fracture time with the introduction of fibres is observed. The experimental results are analysed and discussed with the intent to better understand the mechanical behaviour of UHPFRC materials in case of dynamic event under service loading conditions.

scholarly journals Development and Application of a Novel Pluri-Residue Method to Determine Polar Pesticides in Fruits and Vegetables through Liquid Chromatography High Resolution Mass Spectrometry

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 553
Author(s):  
Lorena Manzano-Sánchez ◽  
José Antonio Martínez-Martínez ◽  
Irene Domínguez ◽  
José Luis Martínez Vidal ◽  
Antonia Garrido Frenich ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Resolution ◽  
High Performance ◽  
Fruits And Vegetables ◽  
High Resolution Mass Spectrometry ◽  
Stationary Phases ◽  
Mean Values ◽  
Polar Pesticides ◽  
Relative Standard ◽  
The Matrix

Nowadays, highly polar pesticides are not included in multiresidue methods due to their physico-chemical characteristics and therefore, specific analytical methodologies are required for their analysis. Laboratories are still looking for a pluri-residue method that encompasses the largest number of polar pesticides. The aim of this work was the simultaneous determination of ethephon, 2-hydroxyethylphosphonic acid (HEPA), fosetyl aluminum, glyphosate, aminomethylphosphonic acid (AMPA), N-acetyl-glyphosate and N-acetyl-AMPA in tomatoes, oranges, aubergines and grapes. For that purpose, an ultra high performance liquid chromatography (UHPLC) coupled to a high resolution single mass spectrometer Orbitrap-MS were used. Different stationary phases were evaluated for chromatographic separation, and among them, the stationary phase Torus DEA provided the best separation of the selected compounds. The QuPPe method was used for the extraction of the analytes, but slight modifications were needed depending on the matrix. The developed method was validated, observing matrix effect in all matrices. Intra- and inter-day precision were estimated, and relative standard deviation were lower than 19%. Recoveries were satisfactory, and mean values ranged from 70% to 110%. Limits of quantification were between 25 and 100 µg kg−1. Finally, the analytical method was applied to different fruits and vegetables (oranges, tomatoes, aubergines and grapes).

Measurement accuracy and Cerenkov removal for high performance, high spatial resolution scintillation dosimetry

2005 ◽  
Vol 33 (1) ◽  
pp. 128-135 ◽  
Author(s):  
Louis Archambault ◽  
A. Sam Beddar ◽  
Luc Gingras ◽  
René Roy ◽  
Luc Beaulieu
Keyword(s):  
Spatial Resolution ◽  
High Performance ◽  
Measurement Accuracy ◽  
High Spatial Resolution

scholarly journals An ultrahigh-resolution soft x-ray microscope for quantitative analysis of chemically heterogeneous nanomaterials

2020 ◽  
Vol 6 (51) ◽  
pp. eabc4904
Author(s):  
David A. Shapiro ◽  
Sergey Babin ◽  
Richard S. Celestre ◽  
Weilun Chao ◽  
Raymond P. Conley ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Performance ◽  
Ultrahigh Resolution ◽  
High Brightness ◽  
X Ray ◽  
Correlative Analysis ◽  
Scanning Transmission ◽  
Chemical States ◽  
Scanning Mechanism ◽  
Performance Computing

The analysis of chemical states and morphology in nanomaterials is central to many areas of science. We address this need with an ultrahigh-resolution scanning transmission soft x-ray microscope. Our instrument provides multiple analysis tools in a compact assembly and can achieve few-nanometer spatial resolution and high chemical sensitivity via x-ray ptychography and conventional scanning microscopy. A novel scanning mechanism, coupled to advanced x-ray detectors, a high-brightness x-ray source, and high-performance computing for analysis provide a revolutionary step forward in terms of imaging speed and resolution. We present x-ray microscopy with 8-nm full-period spatial resolution and use this capability in conjunction with operando sample environments and cryogenic imaging, which are now routinely available. Our multimodal approach will find wide use across many fields of science and facilitate correlative analysis of materials with other types of probes.

ADDITIVE MANUFACTURING OF HIGH-LOADING POLYMER NANOCOMPOSITES WITH MULTISCALE ALIGNMENT

2021 ◽  
Author(s):  
SOYEON PARK ◽  
KUN (KELVIN) FU
Keyword(s):  
Additive Manufacturing ◽  
Polymer Nanocomposites ◽  
High Performance ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
High Productivity ◽  
Macro Scale ◽  
The Matrix ◽  
Multiscale Structures ◽  
Printing Direction

Polymer nanocomposites have advantages in mechanical, electrical, and optical properties compared to individual components. These unique properties of the nanocomposites have attracted attention in many applications, including electronics, robotics, biomedical fields, automotive industries. To achieve their high performance, it is crucial to control the orientation of nanomaterials within the polymer matrix. For example, the electric conductivity will be maximized in the ordered direction of conductive nanomaterials such as graphene and carbon nanotubes (CNTs). Conventional fabrication methods are commonly used to obtain polymer nanocomposites with the controlled alignment of nanomaterials using electric or magnetic fields, fluid flow, and shear forces. Such approaches may be complex in preparing a manufacturing system, have low fabrication rate, and even limited structure scalability and complexity required for customized functional products. Recently, additive manufacturing (AM), also called 3D printing, has been developed as a major fabrication technology for nanocomposites with aligned reinforcements. AM has the ability to control the orientation of nanoparticles and offers a great way to produce the composites with cost-efficiency, high productivity, scalability, and design flexibility. Herein, we propose a manufacturing process using AM for the architected structure of polymer nanocomposites with oriented nanomaterials using a polylactic acid polymer as the matrix and graphite and CNTs as fillers. AM can achieve the aligned orientation of the nanofillers along the printing direction. Thus, it enables the fabrication of multifunctional nanocomposites with complex shapes and higher precision, from micron to macro scale. This method will offer great opportunities in the advanced applications that require complex multiscale structures such as energy storage devices (e.g., batteries and supercapacitors) and structural electronic devices (e.g., circuits and sensors).

Mechanical Properties of Matrix Hybrid Thick-Composites

Materials ◽  
2004 ◽  
Author(s):  
Hiroyuki Hamada ◽  
Asami Nakai ◽  
Kazuya Eto ◽  
Kenichi Sugimoto
Keyword(s):  
Mechanical Properties ◽  
Hybrid Composite ◽  
High Performance ◽  
Impact Load ◽  
Unsaturated Polyester ◽  
In Situ Observation ◽  
Impact Properties ◽  
The Matrix ◽  
Low Modulus ◽  
Thick Composites

For the purpose of more safety boats, the large thickness of outer plates is required to increase flexural stiffness, strength and impact properties. Some problems in mechanical properties are generated by increasing in thickness because the effect of interlaminar shearing of Thick-composites on whole mechanical properties is greater than that of thin-composites. We have investigated the matrix hybrid composite with two kinds of unsaturated polyester, one was hard type resin with low toughness and the other was flexible type resin with low modulus and high toughness. In this study, matrix hybrid composite was focused and applied to Thick-composites. First, the flexural properties were investigated and the micro fracture progress was precisely observed with in-situ observation using replica method. Then, impact properties of the Thick-composites were examined and the availability of matrix hybrid composite was investigated. It was concluded that the matrix hybrid composite achieved high performance in both static and impact load.

scholarly journals Development of Low-Cost Fast Photoacoustic Computed Tomography: System Characterization and Phantom Study

2019 ◽  
Vol 9 (3) ◽  
pp. 374 ◽  
Author(s):  
Mohsin Zafar ◽  
Karl Kratkiewicz ◽  
Rayyan Manwar ◽  
Mohammad Avanaki
Keyword(s):  
Computed Tomography ◽  
Spatial Resolution ◽  
Temporal Resolution ◽  
High Performance ◽  
Low Cost ◽  
Single Element ◽  
Tomography System ◽  
System Characterization ◽  
2D Images ◽  
Fast Rotating

A low-cost Photoacoustic Computed Tomography (PACT) system consisting of 16 single-element transducers has been developed. Our design proposes a fast rotating mechanism of 360o rotation around the imaging target, generating comparable images to those produced by large-number-element (e.g., 512, 1024, etc.) ring-array PACT systems. The 2D images with a temporal resolution of 1.5 s and a spatial resolution of 240 µm were achieved. The performance of the proposed system was evaluated by imaging complex phantom. The purpose of the proposed development is to provide researchers a low-cost alternative 2D photoacoustic computed tomography system with comparable resolution to the current high performance expensive ring-array PACT systems.

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