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  • 1
    Keywords: Hochschulschrift ; Meerwasser ; Spurenelement ; Mikroanalyse
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (xx, 159 Seiten) , Illustrationen
    DDC: 572.5
    Language: English
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  • 2
    ISSN: 1573-2568
    Keywords: cholangiocellular carcinoma ; p53 ; proliferation markers ; apoptosis ; histopathological parameters ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study was performed to examine the correlation between mutations of the p53 tumor suppressor gene, the occurrence of apoptosis, and proliferation in cholangiocellular carcinoma of the liver. The results obtained were compared with pathohistological stage (according to UICC) and grade and with disease related survival rate. In 41 curatively (R0−) resected intrahepatic cholangiocellular carcinomas, the status of the p53 gene was determined by direct sequencing of exons 4–9 and immunohistochemically. Apoptosis was assessed using the in situ end labeling (ISEL) technique in combination with morphological criteria. Proliferation was analyzed by immunohistochemistry of MIB-1 (Ki-67), Proliferating cell nuclear antigen (PCNA), and silver-stained nucleolar organizer regions (AgNOR). The results obtained were compared with pathohistological stage (according to UICC), grade, several other histopathological factors, and survival rate. Mutations of p53 were detected in 15/41 carcinomas examined (37%). The most common change was a G→C and C→T transition, changing the hot spot amino acid determined by exons 4–8. Of these 15 tumors, 14 were also p53-positive by immunohistochemistry. In each carcinoma examined, we could demonstrate MIB-1, PCNA, and AgNOR dots and also apoptotic cells in variable proportions. The proliferation markers showed a significant correlation among themselves. In univariate survival analysis, the extent of the primary tumor, lymph node status, grade, and p53 were significant factors influencing patient survival. Performing multivariate Cox regression survival analysis, however, only the extent of primary tumor and lymph node status had an independent prognostic impact. Apoptosis was not related to patient prognosis or to other parameters examined. In conclusion, these results indicated that p53 could serve as an additional prognostic parameter that could provide auxiliary information for patient outcome. However, tumor stage and lymph node involvement were the strongest prognostic factors. We failed to establish apoptosis or other pathological parameters as factors predicting the prognosis of patients with cholangiocellular carcinoma.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2021-04-23
    Description: The trace metal iron (Fe) is an essential micronutrient for phytoplankton growth and limits, or co-limits primary production across much of the world's surface ocean. Iron is a redox sensitive element, with Fe(II) and Fe(III) co-existing in natural waters. Whilst Fe(II) is the most soluble form, it is also transient with rapid oxidation rates in oxic seawater. Measurements of Fe(II) are therefore preferably undertaken in situ. For this purpose an autonomous wet chemical analyzer based on lab-on-chip technology was developed for the in situ determination of the concentration of dissolved (〈0.45 μm) Fe species (Fe(II) and labile Fe) suitable for deployments in a wide range of aquatic environments. The spectrophotometric approach utilizes a buffered ferrozine solution and a ferrozine/ascorbic acid mixture for Fe(II) and labile Fe(III) analyses, respectively. Diffusive mixing, color development and spectrophotometric detection take place in three separate flow cells with different lengths such that the analyzer can measure a broad concentration range from low nM to several μM of Fe, depending on the desired application. A detection limit of 1.9 nM Fe was found. The microfluidic analyzer was tested in situ for nine days in shallow waters in the Kiel Fjord (Germany) along with other sensors as a part of the SenseOCEAN EU-project. The analyzer's performance under natural conditions was assessed with discrete samples collected and processed according to GEOTRACES protocol [acidified to pH 〈 2 and analyzed via inductively coupled plasma mass spectrometry (ICP-MS)]. The mechanical performance of the analyzer over the nine day period was good (consistent high precision of Fe(II) and Fe(III) standards with a standard deviation of 2.7% (n = 214) and 1.9% (n = 217), respectively, and successful completion of every programmed data point). However, total dissolved Fe was consistently low compared to ICP-MS data. Recoveries between 16 and 75% were observed, indicating that the analyzer does not measure a significant fraction of natural dissolved Fe species in coastal seawater. It is suggested that an acidification step would be necessary in order to ensure that the analyzer derived total dissolved Fe concentration is reproducible and consistent with discrete values.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
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  • 4
    Publication Date: 2018-10-01
    Type: Report , NonPeerReviewed , info:eu-repo/semantics/book
    Format: text
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  • 5
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    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, ? pp
    Publication Date: 2022-01-31
    Description: There has been an increasing demand over the last decades for autonomous in situ measurement systems for the quantification of physical and chemical parameters in the marine environment. The demand is largely linked to the need to address the present undersampling of the world’s oceans. The need for reliable and well resolved time series, both on a temporal and spatial scale, cannot be satisfied with conventional approaches involving collection of discrete samples during ship campaigns followed by their analysis in a land-based laboratory. This PhD project investigates whether the well-established spectrophotometric approaches for Fe and Mn using Ferrozine (FZ) and 1-(2-pyridylazo)-2-naphthol (PAN) as complexing agents, respectively, can be utilized for reliable and accurate in situ quantification of dissolved Fe and Mn species in an autonomous wet chemical analyzer based on lab-on-chip (LoC) technology. Those systems are based around a microfluidic chip and integrate all steps of analysis (sampling, sample treatment, chemical reaction, detection, data processing) into a single instrument.
    Type: Thesis , NonPeerReviewed
    Format: text
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  • 6
    Publication Date: 2022-03-09
    Description: Herein, we present a small and versatile optode system with integrated battery and logger for monitoring of O-2, pH, and pCO(2) in seawater. Three sensing materials designed for seawater measurements are optimized with respect to dynamic measurement range and long-term stability. The spectral properties of the sensing materials were tailored to be compatible with a commercially available laboratory oxygen logger that was fitted into a pressure housing. Interchangeable sensor caps with appropriate "sensing chemistry" are conveniently attached to the end of the optical fiber. This approach allows using the same instrument for multiple analytes, which offers great flexibility and minimizes hardware costs. Applications of the new optode system were demonstrated by recording depth profiles for the three parameters during a research cruise in the Baltic Sea and by measuring surface water transects of pH. The optode was furthermore used to monitor the concentration of dissolved oxygen in a seagrass meadow in the Limfjord, Denmark, and sensor packages consisting of pO(2), pH, and pCO(2) were deployed in the harbors of Kiel, Germany, and Southampton, England, for 6 d. The measurements revealed that the system can resolve typical patterns in seawater chemistry related to spatial heterogeneities as well as temporal changes caused by biological and tidal activity.
    Type: Article , PeerReviewed
    Format: text
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  • 7
    Publication Date: 2024-02-07
    Description: The extensive use of silver nanoparticles (AgNPs) in consumer products, medicine, and industry leads to their release into the environment. Thus, a characterization of the concentration, size, fate, and toxicity of AgNPs under environmental conditions is required. In this study, we present the characterization and optimization of an asymmetric flow field-flow fractionation (AF4) system coupled with UV/Vis spectrophotometer and dynamic light scattering (DLS) detector as a powerful tool for the size separation and multi-parameter characterization of AgNPs in complex matrices. The hyphenated AF4-UV/Vis-DLS system was first characterized using individual injections of the different size fractions. We used electrostatically stabilized AgNPs of 20-, 50-, and 80-nm nominal diameters coated with lipoic acid. We investigated the effect of applied cross-flows, carrier solutions, focus times, and quantity of injected particles on the nature of the AF4 fractograms and on the integrity of the AgNPs. Best size separation of a 1:1 mixture of 20- and 80-nm AgNPs was achieved using cross-flows of 0.5 and 0.7 mL/min with 1 mM NaCl and 0.05% v/v Mucasol as carrier solutions. We also researched the behavior of AgNPs in natural waters using the hyphenated AF4-UV/Vis-DLS system, under determined optimal conditions.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: text
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  • 8
    Publication Date: 2024-02-07
    Description: A spectrophotometric approach for quantification of dissolved manganese (DMn) with 1-(2-pyridylazo)-2-naphthol (PAN) has been adapted for in situ application in coastal and estuarine waters. The analyser uses a submersible microfluidic lab-on-chip device, with low power (~ 1.5 W) and reagent consumption (63 µL per sample). Laboratory characterization showed an absorption coefficient of 40,838 ± 1127 L⋅mol−1⋅cm−1 and a detection limit of 27 nM, determined for a 34.6 mm long optical detection cell. Laboratory tests showed that long-term stability of the PAN reagent was achieved by addition of 4% v/v of a non-ionic surfactant (Triton-X100). To suppress iron (Fe) interferences with the PAN reagent, the Fe(III) masking agents deferoxamine mesylate (DFO-B) or disodium 4,5-dihydroxy-1,3-benzenedisulfonate (Tiron) were added and their Fe masking efficiencies were investigated. The analyser was tested during a deployment over several weeks in Kiel Fjord (Germany), with successful acquisition of 215 in situ data points. The time series was in good agreement with DMn concentrations determined from discretely collected samples analysed via inductively coupled plasma mass spectrometry (ICP-MS), exhibiting a mean accuracy of 87% over the full deployment duration (with an accuracy of 〉 99% for certain periods) and clear correlations to key hydrographic parameters.
    Type: Article , PeerReviewed
    Format: text
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  • 9
    Publication Date: 2023-09-28
    Description: Water samples were taken in September 2019 in the southern German Bight (between Bremerhaven, Cuxhaven, Helgoland and Sylt). The surface water samples were later analyzed by AWI, Geomar and HZG laboratories for nutrients, carbon compounds and pigments. Samples were fixed by filtering and freezing (nutrients, POC, pigments) or poisoning (TA, DOC)
    Keywords: 19-Hexanoyloxyfucoxanthin; after Dickson et al. (2007); after Irving and Frey (1984); Alkalinity, total; Alloxanthin; Ammonium; beta-Carotene; Carbon, organic, dissolved; Carbon, organic, particulate; Chlorophyll a; Chlorophyll b; Chlorophyllide a; Comment; DEPTH, water; Diadinoxanthin; Diatoxanthin; Element analyse, Eurovector after Sharp (1974); Event label; Fucoxanthin; High Performance Liquid Chromatography (HPLC 2695), Wiltshire et al. 1998; Lutein; M1; M10; M11; M12; M13; M14; M15; M16; M17; M18; M19; M2; M20; M21; M22; M23; M24; M25; M26; M27; M28; M29; M3; M30; M31; M32; M4; M5; M6; M7; M8; M9; Modular Observation Solutions for Earth Systems; MOSES; MYA2020/08_stern_5; Mya II; Neoxanthin; Nitrate; Nitrite; OPTIMARE Precision Salinometer System; Oxygen, dissolved; Peridinin; Phosphate; Salinity; SEAL Analytical, AutoAnalyzer QuAAtro39, method No. Q-066-05 Rev. 3; Shimadzu TOC-VCPH total organic carbon analyzer; Silicate; stern_5-M1; stern_5-M10; stern_5-M11; stern_5-M12; stern_5-M13; stern_5-M14; stern_5-M15; stern_5-M16; stern_5-M17; stern_5-M18; stern_5-M19; stern_5-M2; stern_5-M20; stern_5-M21; stern_5-M22; stern_5-M23; stern_5-M24; stern_5-M25; stern_5-M26; stern_5-M27; stern_5-M28; stern_5-M29; stern_5-M3; stern_5-M30; stern_5-M31; stern_5-M32; stern_5-M4; stern_5-M5; stern_5-M6; stern_5-M7; stern_5-M8; stern_5-M9; Sternfahrt 5; Titration, Winkler; Turbidity; Violaxanthin; Water sample; WS; Zeaxanthin
    Type: Dataset
    Format: text/tab-separated-values, 560 data points
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  • 10
    Publication Date: 2023-09-28
    Keywords: 19-Hexanoyloxyfucoxanthin; after Dickson et al. (2007); Alkalinity, total; Alloxanthin; Astaxanthin; beta-Carotene; Carbon, inorganic, dissolved; Carbon, organic, dissolved; Carbon, organic, particulate; Chlorophyll a; Chlorophyll a, epimer; Chlorophyll a allomers; Chlorophyll b; Chlorophyll c2; Chlorophyllide a; Colorimetric using QuAAtro39 AA (Seal Analytical); Comment; DEPTH, water; Diadinoxanthin; Diatoxanthin; Element analyse, Eurovector after Sharp (1974); Event label; Fucoxanthin; L1; L11; L13; L15; L17; L19; L20_stern_5; L21; L23; L25; L27; L29; L30; L32; L33; L34; L36; L38; L4; L43; L45; L48; L51; L54; L57; L58; L61; L62; L63; L65; L7; L8; L9; Littorina; Lutein; Mg-2,4-divinyl pheoporphyrin a5 monomethyl ester; Modular Observation Solutions for Earth Systems; MOSES; Neoxanthin; Nitrate; Nitrite; OPTIMARE Precision Salinometer System; Oxygen, dissolved; Peridinin; Phosphate; Prasinoxanthin; Salinity; Shimadzu TOC-VCPH total organic carbon analyzer; Silicate; stern_5-L1; stern_5-L11; stern_5-L13; stern_5-L15; stern_5-L17; stern_5-L19; stern_5-L21; stern_5-L23; stern_5-L25; stern_5-L27; stern_5-L29; stern_5-L30; stern_5-L32; stern_5-L33; stern_5-L34; stern_5-L36; stern_5-L38; stern_5-L4; stern_5-L43; stern_5-L45; stern_5-L48; stern_5-L51; stern_5-L54; stern_5-L57; stern_5-L58; stern_5-L61; stern_5-L62; stern_5-L63; stern_5-L65; stern_5-L7; stern_5-L8; stern_5-L9; Sternfahrt 5; Thermo Scientific UltiMate 3000 high-performance liquid chromatography instrument (HPLC) (van Heukelem 2001); Titration, Winkler; Violaxanthin; Water sample; WS; Zeaxanthin
    Type: Dataset
    Format: text/tab-separated-values, 880 data points
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