scholarly journals A Microfluidic Split-Flow Technology for Product Characterization in Continuous Low-Volume Nanoparticle Synthesis

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 179 ◽  
Author(s):  
Holger Bolze ◽  
Peer Erfle ◽  
Juliane Riewe ◽  
Heike Bunjes ◽  
Andreas Dietzel ◽  
...  
Keyword(s):  
Continuous Process ◽  
Nanoparticle Synthesis ◽  
Measuring Channel ◽  
Detection Methods ◽  
Feedback Signal ◽  
Segmented Flow ◽  
Small Stream ◽  
Fluorescence Measurements ◽  
Flow Splitting ◽  
Product Stream

A key aspect of microfluidic processes is their ability to perform chemical reactions in small volumes under continuous flow. However, a continuous process requires stable reagent flow over a prolonged period. This can be challenging in microfluidic systems, as bubbles or particles easily block or alter the flow. Online analysis of the product stream can alleviate this problem by providing a feedback signal. When this signal exceeds a pre-defined range, the process can be re-adjusted or interrupted to prevent contamination. Here we demonstrate the feasibility of this concept by implementing a microfluidic detector downstream of a segmented-flow system for the synthesis of lipid nanoparticles. To match the flow rate through the detector to the measurement bandwidth independent of the synthesis requirements, a small stream is sidelined from the original product stream and routed through a measuring channel with 2 × 2 µm cross-section. The small size of the measuring channel prevents the entry of air plugs, which are inherent to our segmented flow synthesis device. Nanoparticles passing through the small channel were detected and characterized by quantitative fluorescence measurements. With this setup, we were able to count single nanoparticles. This way, we were able to detect changes in the particle synthesis affecting the size, concentration, or velocity of the particles in suspension. We envision that the flow-splitting scheme demonstrated here can be transferred to detection methods other than fluorescence for continuous monitoring and feedback control of microfluidic nanoparticle synthesis.

scholarly journals Permafrost Dynamics and Degradation in Polar Arctic From Satellite Radar Observations, Yamal Peninsula

2021 ◽  
Vol 9 ◽  
Author(s):  
Kanayim Teshebaeva ◽  
Ko J. van Huissteden ◽  
Helmut Echtler ◽  
Alexander V. Puzanov ◽  
Dmitry N. Balykin ◽  
...  
Keyword(s):  
Time Series ◽  
Continuous Process ◽  
Yamal Peninsula ◽  
Observation Data ◽  
Surface Dynamics ◽  
Stream Channels ◽  
Small Stream ◽  
Surface Features ◽  
Satellite Radar ◽  
Sar Imagery

We investigate permafrost surface features revealed from satellite radar data in the Siberian arctic at the Yamal peninsula. Surface dynamics analysis based on SRTM and TanDEM-X DEMs shows up to 2 m net loss of surface relief between 2000 and 2014 indicating a highly dynamic landscape. Surface features for the past 14 years reflect an increase in small stream channels and a number of new lakes that developed, likely caused by permafrost thaw. We used Sentinel-1 SAR imagery to measure permafrost surface changes. Owing to limited observation data we analyzed only 2 years. The InSAR time-series has detected surface displacements in three distinct spatial locations during 2017 and 2018. At these three locations, 60–120 mm/yr rates of seasonal surface permafrost changes are observed. Spatial location of seasonal ground displacements aligns well with lithology. One of them is located on marine sediments and is linked to anthropogenic impact on permafrost stability. Two other areas are located within alluvial sediments and are at the top of topographic elevated zones. We discuss the influence of the geologic environment and the potential effect of local upwelling of gas. These combined analyses of InSAR time-series with analysis of geomorphic features from DEMs present an important tool for continuous process monitoring of surface dynamics as part of a global warming risk assessment.

scholarly journals Complex interactions of in-stream DOM and nutrient spiralling unravelled by Bayesian regression analysis

2020 ◽  
Author(s):  
Matthias Pucher ◽  
Peter Flödl ◽  
Daniel Graeber ◽  
Klaus Felsenstein ◽  
Thomas Hein ◽  
...  
Keyword(s):  
Nitrate Uptake ◽  
Soluble Reactive Phosphorus ◽  
Transport Processes ◽  
Bayesian Regression ◽  
Nutrient Concentrations ◽  
Small Stream ◽  
Fluorescence Measurements ◽  
Wide Range ◽  
Non Linear ◽  
Nutrient Spiralling

Abstract. Uptake and release patterns of dissolved organic matter (DOM) compounds and nutrients are entangled, and the current literature does not provide a consistent picture of the link between DOM composition, nutrient concentrations, and effects on their cycling. We performed two plateau addition experiments for each of five different, realistic, complex DOM leachates in a small stream, heavily enriched in nitrate but not phosphate or DOM due to diffuse agricultural pollution. By including cow and pig dung as well as corn, leaves and nettles leachates, the study used a wide range of different DOM qualities. We measured changes in nutrient concentrations and determined DOM fractions by fluorescence measurements and parallel factor (PARAFAC) decomposition. To assess influences from hydrological transport processes, we used a 1-D hydrodynamic model. We propose a non-linear Bayesian approach to the nutrient spiralling concept, the Interactions in Nutrient Spirals using BayesIan REgression (INSBIRE) approach. This approach can disentangle complex and interacting biotic and abiotic drivers in nutrient uptake metrics, show their variability and quantify their error distribution. Furthermore, previous knowledge on nutrient spiralling can be included in the model using prior probability distributions. We used INSBIRE to assess interactions of compound-specific DOM and nutrient spiralling metrics the data of our experiment. The uptake processes of different DOM fractions were linked to each other. We observed stimulating and dampening effects of DOM fractions on each other and the overall DOM uptake. We found saturation effects for dissolved organic carbon (concentration of C, DOC) uptake, as rising concentrations of a DOM fraction dampened its uptake. The degradation of a humic DOM component of terrestrial origin was stimulated by other DOM fractions, pointing to priming effects. We also found an influence of the wetted width on the uptake of soluble reactive phosphorus (SRP) and a microbially derived humic substance, which indicates the importance of the sediment-water interface for P and humic C cycling in the studied stream. Interestingly, we found no interactions between DOM uptake and nitrate or SRP concentrations, or any effect of the added DOM leachates on nitrate uptake, indicating that the increase in DOC concentrations and SRP concentrations were not sufficient to affect the relatively steady nitrate uptake during the experiments. Overall, we show that bulk DOC is a weak predictor of DOC uptake behaviour for complex DOM leachates and that individual DOM compound uptake, nitrate uptake and SRP uptake are controlled very differently within the same aquatic ecosystem. We also found effects of hydromorphology on the uptake of one humic fluorophore and SRP. We conclude that cycling of different C fractions, their interaction and interactions with N and P uptake in streams is a complex, non-linear problem, which can only be assessed with advanced non-linear approaches, such as we present with INSBIRE.

scholarly journals Generation of Cardiomyocytes in Pipe-Based Microbioreactor Under Segmented Flow

2016 ◽  
Vol 38 (5) ◽  
pp. 1883-1896 ◽  
Author(s):  
Dimitry Spitkovsky ◽  
Karen Lemke ◽  
Tobias Förster ◽  
Robert Römer ◽  
Stefan Wiedemeier ◽  
...  
Keyword(s):  
Embryoid Body ◽  
Es Cells ◽  
Continuous Process ◽  
Embryonic Stem ◽  
Cardiac Cells ◽  
Egfp Expression ◽  
Segmented Flow ◽  
Differentiation Potential ◽  
Further Development ◽  
Gas Supply

Background/Aims: Embryonic stem (ES) cells have got a broad range differentiation potential. The differentiation is initiated via aggregation of non-differentiated ES cells into embryoid body (EB) capable of multi-lineage development. However experimental variables present in standard differentiation techniques lead to high EB heterogeneity, affecting development into the cells of desired lineage, and do not support the process automatization and scalability. Methods: Here we present a novel pipe based microbioreactor (PBM) setup based on segmented flow, designed for spatial maintenance of temperature, nutrition supply, gas supply and sterility. Results: We verified PBM feasibility for continuous process generating cardiac cells starting from single ES cell suspension followed by EB formation for up to 10 days. The ES cells used in the study were genetically modified for cardiac-specific EGFP expression allowing optical monitoring of cardiomyocytes while EBs remained within PBM for up to 10 days. Efficiency of cardiac cells formation within PBM was similar compared to a standard hanging drop based protocol. Conclusion: Our findings ensure further development of microfluidic bioreactor technology to enable robust cardiomyocytes production for needs of drug screening, tissue engineering and other applications.

scholarly journals New generation of oxide-based nanoparticles for the applications in early cancer detection and diagnostics

2020 ◽  
Vol 9 (1) ◽  
pp. 274-302 ◽  
Author(s):  
Michal M. Godlewski ◽  
Jaroslaw Kaszewski ◽  
Paula Kielbik ◽  
Jaroslaw Olszewski ◽  
Waldemar Lipinski ◽  
...  
Keyword(s):  
Cancer Detection ◽  
Nanoparticle Synthesis ◽  
Developed Countries ◽  
Cancer Diagnostics ◽  
Detection Methods ◽  
Oxide Nanoparticles ◽  
Gadolinium Contrast ◽  
Potential Applications ◽  
Gadolinium Contrast Agents ◽  
New Generation

AbstractHereby the possible applications of oxide nanoparticles in the cancer diagnostics and therapy are presented. Cancer diseases are nowadays one of the most common causes of death in the highly-developed countries. Discussed will be the current clinical cancer detection methods with their shortcomings. The role of nanomedicine in cancer medicine and the potential applications of nanoparticles debated in the literature will be critically evaluated. In the second part, the most common methods for the nanoparticle synthesis will be discussed. Finally, the system for cancer detection based on the enhanced permeation-retention of multimodal high-k oxide nanoparticles doped with lanthanides will be proposed for both for themagnetic resonance imaging (non-gadolinium contrast agents) and for fluorescence guided biopsy and surgery.

Development of the Reliable Fluorometric Assay for the Sensitive Determination of Nitric Oxide Metabolites in Biological Fluids

2013 ◽  
Vol 477-478 ◽  
pp. 1359-1362
Author(s):  
Qiao Yang ◽  
Xiao Ling Zhang ◽  
Hong Liang Huang
Keyword(s):  
Nitric Oxide ◽  
Biological Fluids ◽  
Rapid Screening ◽  
Detection Methods ◽  
Clinical Samples ◽  
No Production ◽  
Fluorescence Measurements ◽  
Large Numbers ◽  
Nitric Oxide Metabolites

In this study, we developed a fluorescence measurements in microplates for high-throughput determination of nitric oxide (NO) metabolites, which is used as a reliable and sensitive marker of NO production, in biological fluids using a pH-independent fluorescence increasing probe, DAMBO-PH. The sensitivity of this method is lower than that of the other detection methods reported in the literature. This method was demonstrated to be useful for the rapid screening of large numbers of biological and clinical samples, and should be an important tool for further clarifying the physiology, pathology and pharmacology roles of NO.

Complex interactions of in-stream DOM and nutrient spiralling unravelled by Bayesian regression analysis

2021 ◽  
Author(s):  
Matthias Pucher ◽  
Peter Flödl ◽  
Daniel Graeber ◽  
Klaus Felsenstein ◽  
Thomas Hein ◽  
...  
Keyword(s):  
Nutrient Uptake ◽  
Nutrient Dynamics ◽  
Gas Production ◽  
Transport Processes ◽  
Bayesian Regression ◽  
Nutrient Concentrations ◽  
Cow Dung ◽  
Small Stream ◽  
Fluorescence Measurements ◽  
Nutrient Spiralling

<p>The carbon cycle in aquatic environments is of high interest because of its effects on water quality and greenhouse gas production as well as its alteration through anthropogenic activities with unknown outcomes. Uptake and release of dissolved organic matter (DOM) compounds is depending on the molecular structure and is strongly linked to N and P dynamics. Current research has not fully revealed the complex patterns behind.</p><p>To investigate the interactions between DOM components, we performed ten plateau addition experiments with different, realistic, complex DOM leachates (cow dung, pig dung, corn, leaves and nettles) in a small stream. The DOM quality was determined by fluorescence measurements and parallel factor (PARAFAC) decomposition and the nutrient concentrations were measured at eleven consecutive points in the stream at plateau conditions. The hydrological transport processes were incorporated by using the results of a 1-D hydrodynamic model.</p><p>The nutrient spiralling concept and its application in nutrient dynamics is a valuable basis for the analysis of our data. However, we could not find a data analysis approach, that suited the nature of our questions and data. Based on previously observed nutrient uptake models, we extended the nutrient spiralling concept by additional non-linear terms to analyse interactions between different DOM components.</p><p>We developed the “Interactions in Nutrient Spirals using BayesIan REgression (INSBIRE)” approach to analyse DOM uptake and retention mechanism. This approach can disentangle complex and interacting biotic and abiotic drivers in nutrient uptake metrics, show their variability and quantify their error distribution. We successfully used INSBIRE to show DOM-compound-specific interactions and draw conclusions from the data of our experiment. The applicability of INSBIRE has still to be tested in other studies, but we see a high potential not only in DOM dynamics but any kind of solute dynamics where interactions are crucial.</p>

DNA nick end labeling: a reliable marker for apoptosis?

1995 ◽  
Vol 53 ◽  
pp. 962-963
Author(s):  
Anne F. Bushnell ◽  
Sarah Webster ◽  
Lynn S. Perlmutter
Keyword(s):  
Cell Death ◽  
Cultured Cells ◽  
Apoptotic Cell ◽  
Morphological Characteristics ◽  
Detection Methods ◽  
Tissue Preparation ◽  
Preparation Methods ◽  
Dna Laddering ◽  
Disease States ◽  
Reliable Marker

Apoptosis, or programmed cell death, is an important mechanism in development and in diverse disease states. The morphological characteristics of apoptosis were first identified using the electron microscope. Since then, DNA laddering on agarose gels was found to correlate well with apoptotic cell death in cultured cells of dissimilar origins. Recently numerous DNA nick end labeling methods have been developed in an attempt to visualize, at the light microscopic level, the apoptotic cells responsible for DNA laddering.The present studies were designed to compare various tissue processing techniques and staining methods to assess the occurrence of apoptosis in post mortem tissue from Alzheimer's diseased (AD) and control human brains by DNA nick end labeling methods. Three tissue preparation methods and two commercial DNA nick end labeling kits were evaluated: the Apoptag kit from Oncor and the Biotin-21 dUTP 3' end labeling kit from Clontech. The detection methods of the two kits differed in that the Oncor kit used digoxigenin dUTP and anti-digoxigenin-peroxidase and the Clontech used biotinylated dUTP and avidinperoxidase. Both used 3-3' diaminobenzidine (DAB) for final color development.

To Tell or Not to Tell, That Is the Question

2006 ◽  
Vol 11 (3) ◽  
pp. 236-243 ◽  
Author(s):  
Knut Dalen
Keyword(s):  
Gender Differences ◽  
Ethics Education ◽  
Ethical Dilemmas ◽  
Continuous Process ◽  
Telephone Counseling ◽  
Counseling Service ◽  
Telephone Service

Ethical dilemmas encountered by psychologists have previously been studied in surveys and as formal ethical complaints. No previous publications have been found in which data from an ethics counseling telephone service for psychologists has been analyzed. The present study examines ethical dilemmas, as presented by members of the Norwegian Psychological Association calling the Ethics Telephone Counseling Service (ETCS) from 2001 through 2003. Psychologists seek counseling for a range of ethical dilemmas. Ethical dilemmas concerning confidentiality are those most commonly presented. Dilemmas concerning integrity are also fairly common, whereas dilemmas concerning competence are rarely presented. The study shows virtually no difference in frequency and nature of consultation based on how long a psychologist has been licensed. This study also shows only minor gender differences in the use of the ETCS. Possible implications for ethics education as a continuous process are discussed.

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