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Integration of solid phase extraction with HILIC-MS/MS for analysis of free amino acids in source water

Journal of Environmental Sciences 2022年第7期34卷 190-196页

作者： Junlang Qiu Caley Craven Nicholas Wawryk kristin Carroll Xing-Fang Li Division of Analytical and Environmental Toxicology Department of Laboratory Medicine and PathologyUniversity of AlbertaEdmontonT6G 2G3Canada School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China

Amino acids(AAs) are prevalent in source water, particularly during spring run-off. Monitoring of amino acids in source water is desirable for water treatment plants(WTP) to indicate changes in source water quality. The objective of this study was to establish analytical procedures for reliable monitoring of amino acids in source water. Therefore, we examined two different methods, large volume inject(LVI) and solid phase extraction(SPE), for sample preparation prior to HILIC-MS/MS. The LVI-HILIC-MS/MS method can provide fast and sensitive detection for clean samples, but suffers from matrix effects, resulting in irreproducible separation and shortening column lifetime. We have demonstrated that SPE was necessary prior to HILIC-MS/MS to achieve reproducible and reliable quantification of AAs in source water. A natural heterocyclic amine 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid(MTCCA) was also included in the method to indicate changes in other natural nitrogenous compounds in source water. The SPE-HILIC-MS/MS method was able to achieve limits of detection from 2.6-3400 ng/L for the amino acids and MTCCA with RSDs( n = 3) of 1.1%-4.8%. As well, retention times(RT) of the analytes were reproducible with variation less than 0.01 min( n = 3) through the entire project. We further applied the SPE-HILICMS/MS method to determine AAs in authentic source water samples collected from two drinking water treatment plants(WTPs) during the 2021 spring run-off season. The results support that the SPE-HILIC-MS/MS method does not require derivatization and can provide reliable, accurate, and robust analysis of AAs and MTCCA in source water, supporting future monitoring of source water quality.

关键词： Water analysis Disinfection byproducts Amino acids HPLC MS HILIC

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Analytical evaluation of steady-state solute distribution in through- diffusion and membrane behavior test under non-perfectly flushing boundary conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 258-267页

作者： Guannian Chen Yuchao Li kristin MSample-Lord Shan Tong School of Civil&Environmental Engineering and Geography Science Ningbo UniversityNingbo315211China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou310058China Ningbo ZCONE High-tech Company Limited Ningbo315000China Department of Civil and Environmental Engineering Villanova UniversityVillanovaPAUSA

The through-diffusion and membrane behavior testing procedure using a closed-system apparatus has been widely used for concurrent measurement of diffusion and membrane efficiency coefficients of low-permeability clay-based barrier ***,the common assumption of perfectly flushing conditions at the specimen boundaries could induce errors in analyses of the diffusion coefficients and membrane *** this study,an innovative pseudo three-dimensional(3D)analytical method was proposed to evaluate solute distribution along the boundary surfaces of the soil-porous disks system,considering the non-perfectly flushing *** results were consistent with numerical models under two scenarios considering different inflow/outflow *** proposed model has been demonstrated to be an accurate and reliable method to estimate solute distributions along the *** calculated membrane efficiency coefficient and diffusion coefficient based on the proposed analytical method are more accurate,resulting in up to 50%less relative error than the traditional approach that adopts the arithmetic mean value of the influent and effluent *** retar-dation factor of the clay specimen also can be calculated with a revised cumulative mass ***,the simulated transient solute transport matched with experimental data from a multi-stage through-diffusion and membrane behavior test,validating the accuracy of the proposed method.

关键词： Diffusion testing Membrane behavior Coupled transport Clay barrier Transport modeling

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Implementation of Caterpillar Inspired Rolling Gait and Nonlinear Control Strategy in a Spherical Robot

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Journal of Bionic Engineering 2018年第2期15卷 313-328页

作者： Abhra Roy Chowdhury Gim Song Soh Shaohui Foong kristin L. Wood Temasek Laboratories Engineering Product Development Pillar Singapore University of Technology and Design Singapore 487372 SUTD-MIT International Design Centre Singapore University of Technology and Design Singapore 487372

This paper presents a novel Central Pattern Generator （CPG） based rolling gait generation in a small-sized spherical robot and its nonlinear control mechanism. A rhythmic rolling pattern mimicking Pleurotya caterpillar is produced for the spherical robot locomotion. A synergetically combined feedforward-feedback control strategy is proposed. The feedforward component is generated from centrally connected network of CPGs in conjunction with nonlinear robot dynamics. Two nonlinear feedback control methods namely integral （first order） Sliding Mode Control （SMC） and High （or second） Order Sliding Mode Control （HOSMC） are proposed to regulate robot stability and gait robustness in the presence of matched parameter uncertainties and bounded external disturbances. Design, implementation and experimental evaluation of both roll gait control strategies for the spherical robot are done on smooth （indoor） and irregular （outdoor） ground surfaces, The performance of robot control is quantified by measuring the roll angle stability, phase plane convergence and wheel velocities. Experimental results show that proposed novel strategy is efficient in producing a stable rolling gait and robust control of a spherical robot on two different types of surfaces. It further shows that proposed high HOSMC strategy is more efficient in robust rolling gait control of a spherical robot compared to an integral first-order SMC on two different ground conditions.

关键词： bioinspired spherical robot rolling gait CPG rolling friction integral first-order SMC control HOSMC

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Linking behavior,life history and food supply with the population dynamics of white-footed mice(Peromyscus leucopus)

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Integrative Zoology 2007年第3期2卷 123-130页

作者： Stephen H.VESSEY kristin B.VESSEY Department of Biological Sciences Bowling Green State UniversityBowling GreenOhioUSA

In this paper we review and integrate key aspects of behavioral and life history traits, food supply and populationdynamics of the white-footed mouse (Peromyscus leucopus), a species that is abundant and widely distributedacross much of eastern North America. Results are based largely on a 33-year mark-and-recapture study in a forestfragment in northwest Ohio, USA. Behavioral plasticity in such reproductive traits as mating system and parentalcare allows this species to adjust quickly to changing environments. The species has a relatively “fast” life history,with rapid attainment of sexual maturity and high fecundity in the face of high mortality rates. Maximal reproductiveeffort early in life enables a rapid population response. Food supply, in the form of mast, determines thesize of the reproducing population in early spring, which, in turn, influences the size of the late summer peak *** peak population size is also affected by short-term weather events possibly acting via the food *** effects of weather and food on population growth are in part mediated through competition, including defenseof space and suppression of reproduction. The inelasticity of female territories appears to set an upper limit topopulation density.

关键词： behavior demography life history mast Peromyscus.

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Complex role for the immune system in initiation and progression of pancreatic cancer

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World Journal of Gastroenterology 2014年第32期20卷 11160-11181页

作者： kristin S Inman Amanda A Francis Nicole R Murray Department of Cancer Biology Mayo Clinic Jacksonville FL 32224United States

The immune system plays a complex role in the development and progression of pancreatic cancer. Inflammation can promote the formation of premalignant lesions and accelerate pancreatic cancer development. Conversely, pancreatic cancer is characterized by an immunosuppressive environment, which is thought to promote tumor progression and invasion. Here we review the current literature describing the role of the immune response in the progressive development of pancreatic cancer, with a focus on the mechanisms that drive recruitment and activation of immune cells at the tumor site, and our current understanding of the function of the immune cell types at the tumor. Recent clinical and preclinical data are reviewed, detailing the involvement of the immune response in pancreatitis and pancreatic cancer, including the role of specific cytokines and implications for disease outcome. Acute pancreatitis is characterized by a predominantly innate immune response, while chronic pancreatitis elicits an immune response that involves both innate and adaptive immune cells, and often results in profound sys-temic immune-suppression. Pancreatic adenocarcinoma is characterized by marked immune dysfunction driven by immunosuppressive cell types, tumor-promoting immune cells, and defective or absent inflammatory cells. Recent studies reveal that immune cells interact with cancer stem cells and tumor stromal cells, and these interactions have an impact on development and progression of pancreatic ductal adenocarcinoma(PDAC). Finally, current PDAC therapies are reviewed and the potential for harnessing the actions of the immune response to assist in targeting pancreatic cancer using immunotherapy is discussed.

关键词： Immune system Pancreatitis Pancreatic ductal adenocarcinoma Immunosuppression Immunotherapy Inflammation

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High-throughput prediction of the ground-state collinear magnetic order of inorganic materials using Density Functional Theory

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npj Computational Materials 2019年第1期5卷 588-598页

作者： Matthew Kristofer Horton Joseph Harold Montoya Miao Liu kristin Aslaug Persson Energy Technologies Area Lawrence Berkeley National LaboratoryBerkeleyCAUSA Institute of Physics Chinese Academy of SciencesBeijingChina Department of Materials Science University of California BerkeleyBerkeleyCA 94720USA

We present a robust,automatic high-throughput workflow for the calculation of magnetic ground state of solid-state inorganic crystals,whether ferromagnetic,antiferromagnetic or ferrimagnetic,and their associated magnetic moments within the framework of collinear spin-polarized Density Functional *** is done through a computationally efficient scheme whereby plausible magnetic orderings are first enumerated and prioritized based on symmetry,and then relaxed and their energies determined through conventional DFT+U *** automated workflow is formalized using the atomate code for reliable,systematic use at a scale appropriate for thousands of materials and is fully *** performance of the workflow is evaluated against a benchmark of 64 experimentally known mostly ionic magnetic materials of non-trivial magnetic order and by the calculation of over 500 distinct magnetic orderings.A non-ferromagnetic ground state is correctly predicted in 95% of the benchmark materials,with the experimentally determined ground state ordering found exactly in over 60% of *** of the ground state magnetic order at scale opens up the possibility of high-throughput screening studies based on magnetic properties,thereby accelerating discovery and understanding of new functional materials.

关键词： state ground ferromagnetic

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Design and synthesis of synthetic UP elements for modulation of gene expression in Escherichia coli

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Synthetic and Systems Biotechnology 2019年第2期4卷 99-106页

作者： kristin V.Presnell Madeleine Flexer-Harrison Hal SAlper McKetta Department of Chemical Engineering The University of Texas at Austin200 E Dean Keeton St.Stop C0400AustinTX78712USA Institute for Cellular and Molecular Biology The University of Texas at Austin2500 Speedway AvenueAustinTX78712USA

Metabolic engineering requires fine-tuned gene expression for most pathway optimization *** develop a suitable suite of promoters,traditional bacterial promoter engineering efforts have focused on modifications to the core region,especially the−10 and−35 regions,of native ***,we demonstrate an alternate,unexplored route of promoter engineering through randomization of the UP element of the promoter—a region that contacts the alpha subunit carboxy-terminal domain instead of the sigma subunit of the RNA polymerase *** this work,we identify five novel UP element sequences through library-based searches in Escherichia *** resulting elements were used to activate the *** core promoter,rrnD promoter,to levels on par and higher than the prevalent strong bacterial promoter,*** relative levels of expression activation were transferrable when applied upstream of alternate core promoter sequences,including rrnA and *** work thus presents and validates a novel strategy for bacterial promoter engineering with transferability across varying core promoters and potential for transferability across bacterial species.

关键词： UP element Promoter engineering Expression modulation

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Evaluation of thermodynamic equations of state across chemistry and structure in the materials project

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npj Computational Materials 2018年第1期4卷 323-329页

作者： Katherine Latimer Shyam Dwaraknath Kiran Mathew Donald Winston kristin A.Persson Department of Physics University of California BerkeleyBerkeleyCA 94720USA Energy Storage and Distributed Resources Division Lawrence Berkeley National LabBerkeleyCA 94720USA Department of Materials Science University of California BerkeleyBerkeleyCA 94720USA

Thermodynamic equations of state(EOS)for crystalline solids describe material behaviors under changes in pressure,volume,entropy and temperature,making them fundamental to scientific research in a wide range of fields including geophysics,energy storage and development of novel *** over a century of theoretical development and experimental testing of energy–volume(E–V)EOS for solids,there is still a lack of consensus with regard to which equation is indeed optimal,as well as to what metric is most appropriate for making this *** this study,several metrics were used to evaluate quality of fit for 8 different EOS across 87 elements and over 100 compounds which appear in the *** findings do not indicate a clear“best”EOS,but we identify three which consistently perform well relative to the rest of the ***,we find that for the aggregate data set,the RMSrD is not strongly correlated with the nature of the compound,e.g.,whether it is a metal,insulator,or semiconductor,nor the bulk modulus for any of the EOS,indicating that a single equation can be used across a broad range of classes of materials.

关键词： materials. solids state

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A Deleted Deletion Site in a New Vector Strain and Exceptional Genomic Stability of Plaque-Purified Modified Vaccinia Ankara(MVA)

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Virologica Sinica 2020年第2期35卷 212-226页

作者： Ingo Jordan Deborah Horn kristin Thiele Lars Haag Katharina Fiddeke Volker Sandig ProBioGen AG.Herbert-Bayer-StraBe 8 13086 BerlinGermany Sartorius Stedim Cellca GmbH.Erwin-Rentschler-Str 21 88471 LaupheimGermany Vironova AB Giivlegatan 2211330 StockholmSweden Department of Laboratory Medicine Karolinska Universitetsjukhuset i Huddinge14152 HuddingeSweden

Vectored vaccines based on highly attenuated modified vaccinia Ankara(MVA) are reported to be immunogenic, tolerant to pre-existing immunity, and able to accommodate and stably maintain very large transgenes. MVA is usually produced on primary chicken embryo fibroblasts, but production processes based on continuous cell lines emerge as increasingly robust and cost-effective alternatives. An isolate of a hitherto undescribed genotype was recovered by passage of a nonplaque-purified preparation of MVA in a continuous anatine suspension cell line(***) in chemically defined *** novel isolate(MVA-CR19) replicated to higher infectious titers in the extracellular volume of suspension cultures and induced fewer syncytia in adherent cultures. We now extend previous studies with the investigation of the point mutations in structural genes of MVA-CR19 and describe an additional point mutation in a regulatory gene. We furthermore map and discuss an extensive rearrangement of the left telomer of MVA-CR19 that appears to have occurred by duplication of the right telomer. This event caused deletions and duplications of genes that may modulate immunologic properties of MVACR19 as a vaccine vector. Our characterizations also highlight the exceptional genetic stability of plaque-purified MVA:although the phenotype of MVA-CR19 appears to be advantageous for replication, we found that all genetic markers that differentiate wildtype and MVA-CR19 are stably maintained in passages of recombinant viruses based on either wildtype or MVA-CR.

关键词： Modified vaccinia Ankara(MVA) MVA-CR19 CR.pIX Suspension cell line Vaccine production Genome stability

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Hybrid quantum-classical convolutional neural networks

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Science China(Physics,Mechanics & Astronomy) 2021年第9期64卷 1-8页

作者： Junhua Liu Kwan Hui Lim kristin LWood Wei Huang Chu Guo He-Liang Huang Information Systems Technology and Design Singapore University of Technology and DesignSingapore 487372Singapore Forth AI Singapore 487372Singapore College of Engineering Design and ComputingUniversity of Colorado DenverColorado 80208USA Guangxi Key Laboratory of Optoelectronic Information Processing Guilin University of Electronic TechnologyGuilin 541004China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Shanghai Branch CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum PhysicsUniversity of Science and Technology of ChinaHefei 201315China Henan Key Laboratory of Quantum Information and Cryptography Zhengzhou 450000China

Deep learning has been shown to be able to recognize data patterns better than humans in specific circumstances or *** parallel,quantum computing has demonstrated to be able to output complex wave functions with a few number of gate operations,which could generate distributions that are hard for a classical computer to *** we propose a hybrid quantum-classical convolutional neural network(QCCNN),inspired by convolutional neural networks(CNNs)but adapted to quantum computing to enhance the feature mapping *** is friendly to currently noisy intermediate-scale quantum computers,in terms of both number of qubits as well as circuit’s depths,while retaining important features of classical CNN,such as nonlinearity and *** also present a framework to automatically compute the gradients of hybrid quantum-classical loss functions which could be directly applied to other hybrid quantum-classical *** demonstrate the potential of this architecture by applying it to a Tetris dataset,and show that QCCNN can accomplish classification tasks with learning accuracy surpassing that of classical CNN with the same structure.

关键词： quantum computing quantum machine learning hybrid quantum-classical algorithm convolutional neural network

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