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generation of diverse neural cell types through direct conversion

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World Journal of Stem Cells 2016年第2期8卷 32-46页

作者： gayle F petersen Padraig M Strappe School of Biomedical Sciences Charles Sturt University

A characteristic of neurological disorders is the loss of critical populations of cells that the body is unable to replace,thus there has been much interest in identifying methods of generating clinically relevant numbers of cells to replace those that have been damaged or *** process of neural direct conversion,in which cells of one lineage are converted into cells of a neural lineage without first inducing pluripotency,shows great potential,with evidence of the generation of a range of functional neural cell types both in vitro and in vivo,through viral and non-viral delivery of exogenous factors,as well as chemical induction *** neural cells have been proposed as an attractive alternative to neural cells derived from embryonic or induced pluripotent stem cells,with prospective roles in the investigation of neurological disorders,including neurodegenerative disease modelling,drug screening,and cellular replacement for regenerative medicine applications,however further investigations into improving the efficacy and safety of these methods need to be performed before neural direct conversion becomes a clinically viable *** this review,we describe the generation of diverse neural cell types via direct conversion of somatic cells,with comparison against stem cell-based approaches,as well as discussion of their potential research and clinical applications.

关键词： Adult stem cells Embryonic stem cells generation of neural cells Induced pluripotent stem cells In vitro differentiation In vivo differentiation Clinical applications Direct conversion Induced neural cells

Signal or cue: the role of structural colors in flower pollination

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Current Zoology 2019年第4期65卷 467-481页

作者： Jair E. garcia Mani Shrestha Scarlett R. Howard Phred petersen Adrian g. Dyer School of Media and Communication RMIT University Melbourne Victoria 3001 Australia Faculty of Information Technology Monash University Clayton Victoria 3800 Australia

Angle dependent colors, such as iridescenee, are produced by structures present on flower petals changing their visual appearanee. These colors have been proposed to act as signals for plantinsect communication. However, there is a paucity of behavioral data to allow for interpretations of how to classify these colors either as a signal or a cue when con sidering the n atural con ditions under which pollination occurs. We sampled flowers from 6 plant species across various viewpoints looking for changes in the visual appearanee of the petals. Spectral characteristics were measured with different instruments to simulate both the spectral and spatial characteristics of honeybee's vision. We show the presenee of color patches produced by angle dependent effects on the petals and the calyx of various species;however, the appearance of the angle dependent color patches significantly varies with viewpoint and would only be resolved by the insect eye at close distances. Behavior experiments with honeybees revealed that pollinators did not use angle dependent colors to drive behavior when presented with novel flower presentations. Results show that angle dependent colors do not comply with the requirements of a signal for plant-pollinator communication since the information transmitted by these colors would be unreliable for potential, free-flying pollination vectors. We thus classify angle dependent colors produced by micro- and ultra-structures as being a cue (a feature which has not evolved for communication), and observe no evidence supporting claims of these angle dependent colors having evolved as visual signal.

关键词： approach angle color flower iridescence photography pollination vision

Role of simple biomarkers in predicting fibrosis progression in HCV infection

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World Journal of gastroenterology 2010年第45期16卷 5710-5715页

作者： Rajasekhara R Mummadi John R petersen Ned Snyder Division of gastroenterology and Hepatology Department of Internal MedicineUniversity of Texas Medical BranchHoustonTX 77025United States Department of Pathology University of Texas Medical BranchHoustonTX 77025United States Department of gastroenterology and Hepatology Kelsey Seybold Clinic2727 W. HolcombeHoustonTX 77025United States

AIM: To examine the accuracy of the aspartate aminotransferase (AST)/Platelet Ratio Index (APRI) and FIB-4, in predicting longitudinal changes in liver histology in hepatitis C virus (HCV) ***: Patients that underwent repeat liver biopsies at least 1 year apart from 1999 to 2007 were identified. Liver fibrosis was staged on needle core biopsies evaluated by a single expert liver pathologist. Only laboratory values within 3 mo of the liver biopsies were ***: Thirty-six patients met the inclusion criteria with 50% stage 1 on initial biopsy, 25% stage 2, and 22% stage 3. Nineteen of 36 (53%) had progression of fibrosis on repeat biopsies, while 16 (44%) showed no change in stage, and one (3%) showed improvement. Patients that showed progression of fibrosis had significantly higher alanine aminotransferase and aspartate aminotransferase levels than the group that did not show progression. A significant correlation was seen between change in stage of fibrosis and change in APRI (r2 = 0.39, P = 0.00001) and a change in FIB-4 (r2 = 0.31, P = 0.00004). A change in APRI (ΔAPRI) of 0.18 had 80% positive predictive value (PPV) and 67% nega- tive predictive value (NPV) for progression of fibrosis. A change in FIB-4 (ΔFIB-4) of 0.39 had 75% PPV and 75% NPV for predicting progression of fibrosis. CONCLUSION: ΔAPRI and ΔFIB-4 parallel changes in fibrosis progression, and could be useful tools for clinicians in following patients with active chronic HCV infection.

关键词： Hepatitis C Liver fibrosis Liver biopsy Biomarkers

Biotechnological approaches in glucosinolate production

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Journal of Integrative Plant Biology 2018年第12期60卷 1231-1248页

作者： Annette petersen Cuiwei Wang Christoph Crocoll Barbara Ann Halkier DynaMo Center Copenhagen Plant Science Centre Department of Plant and Environmental Sciences University of Copenhagen

glucosinolates(gLSs) are sulfur-rich, amino acid-derived defense compounds characteristic of the Brassicales order. In the past, gLSs were mostly known as anti-nutritional factors in fodder, biopesticides in agriculture, and flavors in condiments such as mustard. However, in recent times, gLSs have received increased attention as promoters of human *** has spurred intensive research towards generating rich sources of health-promoting gLSs. We provide a comprehensive overview of the biotechnologica approaches applied to reach this goal. This includes optimization of gLS production and composition in native, gLS-producing plants, including hairy root and cell cultures thereof, as well as synthetic biology approaches in heterologous hosts, such as tobacco and the microbial organisms Escherichia coli and Saccharomyces cerevisiae. The progress using these different approaches is discussed.

关键词： gLS Biotechnological approaches in glucosinolate production

Evaluation of a new qPCR test to identify the organisms causing high total bacterial count in bulk tank milk

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Journal of Integrative Agriculture 2018年第6期17卷 1241-1245页

作者： Jorgen Katholm Lene Trier Olesen Anders petersen Snorri Sigurdsson DNA Diagnostic A/S Risskov 8240Denmark ARLA Foods amba Viby 8260Denmark SEgES Aarhus N 8200Denmark

Milk quality in bulk tank milk （BTM） is measured by flow cytometry technology as total bacterial count （TBC） and somatic cell count （SCC）. To investigate SCC problems, culture or PCR can be used to identify mastitis causing bacteria, e.g., Mastit 4, a commercially available qPCR test. TBC in BTM can be investigated further using culture-based methods such as standard plate count, laboratory pasteurization count, coliform count, and spore counts. To our knowledge, no qPCR addressing the bacteria involved in TBC has been commercially introduced. The aim of this study is to evaluate a recently introduced 3-h qPCR test, TBC 4. The TBC 4 qPCR detects four target groups, Pseudomonas, Streptococci, Enterobacteriacea/ Enterococcus, and Bacillus/Clostridia. These target groups relate to problems on the farm such as cooling, mastitis, environment, and silage. We will continue with new research to compare the TBC 4 qPCR test with traditional culture. For this study, BTM samples from different TBC intervals were selected based on BactoCount results found at routine payment investigation at Eurofins laboratory （Vejen, Denmark）. These samples were analyzed using TBC 4 qPCR assay within 24 h. In total, 346 BTM samples were divided into six different intervals of colony forming units （CFU）. For all four targets in each of the different intervals of CFU, the percent of positive samples, the average Ct-value, the percent of positive samples with Ct〈30 and Ct〈25 were calculated. For Pseudomonas, Streptococci, and Enterobacteriacea/Enterococcus, the number of positive samples with lower Ct-values （high bacteria content） correlated with the CFU mL-1. We found Enterobacteriacea/ Enterococcus, Pseudomonas, and Streptococci in high number of bacteria （Ct〈25） in 25, 19 and 56％ of samples with CFU mL-1 between 50001-100000 and 53, 44, and 39％ in samples with CFU mL-1〉100000. The TBC 4 qPCR test showed to be a strong and fast tool for farmers, advisors and service technicians to address probl

关键词： TBC bulk tank milk qPCR milk quality

Reduced combustion time model for methane in gas turbine flow fields

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Journal of Natural gas Chemistry 2009年第2期18卷 145-155页

作者： Mouna Lamnaouer Robert C. Ryder Andreja Brankovic Eric L. petersen graduate Research Assistant Mechanical Materials & Aerospace Engineering University of Central FloridaOrlando Fl 32816 USA President Engineering Flow ParametricsIvoryton CT USA Vice President Flow ParametricsIvoryton CT USA Associate Professor Department of Mechanical Engineering Texas A&M University College StationTX 77843 USA

Computational fluid dynamics （CFD） modeling of the complex processes that occur within the burner of a gas turbine engine has become a critical step in the design process. However, due to computer limitations, it is very difficult to completely couple the fluid mechanics solver with the full combustion chemistry. Therefore, simplified chemistry models are required, and the topic of this research was to provide reduced chemistry models for CH4/O2 gas turbine flow fields to be integrated into CFD codes for the simulation of flow fields of natural gas-fueled burners. The reduction procedure for the CH4/O2 model utilized a response modeling technique wherein the full mechanism was solved over a range of temperatures, pressures, and mixture ratios to establish the response of a particular variable, namely the chemical reaction time. The conditions covered were between 1000 and 2500 K for temperature, 0.1 and 2 for equivalence ratio in air, and 0.1 and 50 atm for pressure. The kinetic time models in the form of ignition time correlations are given in Arrhenius-type formulas as functions of equivalence ratio, temperature, and pressure; or fuel-to-air ratio, temperature, and pressure. A single ignition time model was obtained for the entire range of conditions, and separate models for the low-temperature and high-temperature regions as well as for fuel-lean and rich cases were also derived. Predictions using the reduced model were verified using results from the full mechanism and empirical correlations from experiments. The models are intended for （but not limited to） use in CFD codes for flow field simulations of gas turbine combustors in which initial conditions and degree of mixedness of the fuel and air are key factors in achieving stable and robust combustion processes and acceptable emission levels. The chemical time model was utilized successfully in CFD simulations of a generic gas turbine combustor with four different cases with various levels of fuel-air premixin

关键词： CH4 ignition time correlations reduced kinetic model

Accelerated tooth movement in Rsk2-deficient mice with impaired cementum formation

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International Journal of Oral Science 2020年第4期12卷 338-345页

作者： Cita Nottmeier Maximilian g.Decker Julia Luther Simon von Kroge Bärbel Kahl-Nieke Michael Amling Thorsten Schinke Julian petersen Till Koehne Department of Orthodontics University Medical Center Hamburg-EppendorfHamburgGermany Institute of Osteology and Biomechanics University Medical Center Hamburg-EppendorfHamburgGermany

Coffin–Lowry–Syndrome(CLS)is a X-linked mental retardation characterized by skeletal dysplasia and premature tooth *** and others have previously demonstrated that the ribosomal S6 kinase RSK2,mutated in CLS,is essential for bone and cementum formation;however,it remains to be established whether RSK2 plays also a role in mechanically induced bone remodeling during orthodontic tooth movement(OTM).We,therefore,performed OTM in wild-type(WT)mice and Rsk2-deficient mice using Nitinol tension springs that were fixed between the upper left molars and the *** untreated contralateral molars served as internal *** 12 days of OTM,the jaws were removed and examined by micro-computed tomography(μCT),decalcified histology,and *** analysis of the untreated teeth confirmed that the periodontal phenotype of Rsk2-deficient mice is characterized by alveolar bone loss and hypoplasia of root *** of OTM usingμCT revealed that OTM was more than two-fold faster in Rsk2-deficient mice as compared to *** also observed that OTM caused alveolar bone loss and root resorptions in WT and Rsk2-deficient ***,quantification of these orthodontic side effects revealed no differences between WT and Rsk2-deficient *** together,Rsk2 loss-of-function accelerates OTM in mice without causing more side effects.

关键词： impaired deficient movement

A methodological framework for analyzing PPgIS data collected in 3D

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International Journal of Digital Earth 2023年第1期16卷 3435-3455页

作者： Kamyar Hasanzadeh Nora Fagerholm Hans Skov-petersen Anton Stahl Olafsson Department of geography and geology University of TurkuTurkuFinland Department of geosciences and Natural Resource Management University of CopenhagenCopenhagenDenmark

Public participation geographic information system(PPgIS)is a facilitated Volunteered geographic Information approach and data collection method that aims to capture the spatial experiences of *** we experience the space around us three-dimensionally,altitude,as the third dimension,has been often absent from PPgis research and *** is largely because of the complexity of implementing surveys in 3D but can also be attributed to a lack of analytical preparedness for using such *** study complements 3D PPgIS data collected from a pilot study of the Aninkainen block in Turku,Finland with synthetic,*** manufactured,data to propose an analytical framework for the study of 3D PPgIS *** analytical framework divides methods based on the geographical scale into two groups:micro-and macro-scale *** this framework,we propose the use of geospatial metrics to analyze 3D PPgIS *** argue that while this multidisciplinary area of research is in its infancy,use of intuitive 3D adapted geometric and landscape metrics can help overcome some of complexities associated with use of this emerging participatory *** conclude by outlining the limitations and envisioning areas for future research.

关键词： 3D gIS landscape metrics PPgIS

Synthesis and characterization of fluorescence active triazole-gold complexes

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Science China Chemistry 2015年第7期58卷 1235-1238页

作者： Boliang Dong Yijin Su Xiaohan Ye Jeffrey L.petersen Xiaodong Shi C.Eugene Bennett Department of Chemistry West Virginia University

Fluorescence active fused-triazole was developed as a ligand in gold(I) cation coordination. The coordination ability was evaluated using NMR and fluorescence emission. Our previously reported N-2-aryl-triazoles, though gave good emission, could not form stable complexes with gold cations. A new N-fused-triazole(NFT) derivative was prepared and the ligand indicated good fluorescence emission, and formed strong coordination with gold cations. Both ligand and complex were characterized by X-ray crystallography. Fluorescence properties of various gold complexes(with different primary ligands) were evaluated, which suggested the feasibility of using fluorescence emission as potential tools for future mechanistic investigation.

关键词： fluorescence catalysis 1 2 3-triazole gold conjugation