| 1. |
- Afifi, Raafat, et al.
(författare)
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SPE and HPLC monitoring of 17-β-estradiol in Egyptian aquatic ecosysetms
- 2016
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Ingår i: Journal of Liquid Chromatography and Related Technologies. - : Informa UK Limited. - 1082-6076 .- 1520-572X. ; 39:8, s. 428-434
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Tidskriftsartikel (refereegranskat)abstract
- Solid-phase extraction and HPLC methods are described for monitoring of 17-β-estradiol residues in Egyptian aquatic ecosystems (water, fish, mollusks, sediment, and drinking water) at the Nile River, Suez Canal region, and northeast of Egypt. Molecular imprinted polymer was prepared and used in extraction. High performance liquid chromatography (HPLC) columns used were Supelcosil C18 and Nucleosil C18. The mobile phases used were different combinations of water and acetonitrile. The concentration of 17-β-estradiol in water, aquatic animals, and sediment samples were of 265.13–7988.12 µg/L, 0.503–96.167, and 0.775–11.884 µg/kg, respectively. Marine lake was contained with high levels of 17-β-estradiol (P < 0.05). Similarly, the Nile River downstream showed high levels of 17-β-estradiol. The detected concentrations in mollusks were significantly higher than those detected in fish. Tilapia fish did not show 17-β-estradiol. Contrarily, low concentrations were detected in the rivulet streams supplied by the Nile River. Besides, 17-β-estradiol was also detected in the sediments at low levels. Detection of 17-β-estradiol in the Egyptian ecosystems attracted attention toward heavy reliance on some esterogenic medicinal products in Egypt. The monitoring of 17-β-estradiol in other water bodies was recommended. Besides, the development of methodologies of bioremediation to eliminate 17-β-estradiol from the Egyptian and other water resources of the world was also suggested.
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| 2. |
- Ander, Malin, et al.
(författare)
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Development of health-related quality of life and symptoms of anxiety and depression among persons diagnosed with cancer during adolescence : a 10-year follow-up study
- 2016
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Ingår i: Psycho-Oncology. - : Wiley. - 1057-9249 .- 1099-1611. ; 25:5, s. 582-589
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The main aim was to investigate the development of health-related quality of life (HRQOL) and symptoms of anxiety and depression in a cohort diagnosed with cancer during adolescence from shortly after up to 10 years after diagnosis.Methods: Participants (n = 61) completed the SF-36 and the HADS shortly; six, 12, and 18 months; and two, three, four, and 10 years (n = 28) after diagnosis. Polynomial change trajectories were used to model development.Results: Polynomial change trajectories showed an initial increase which abated over time into a decrease which abated over time for the SF-36 subscales Mental Health and Vitality; an initial decline which abated over time into an increase for HADS anxiety; and an initial decline which abated over time into an increase which abated over time for HADS depression. The SF-36 mental component summary showed no change from two to 10 years after diagnosis whereas the SF-36 physical component summary showed an increase from two years after diagnosis which declined over time. Ten years after diagnosis 29% reported possible anxiety.Conclusions: Development of HRQOL and symptoms of anxiety and depression appears to be nonlinear among persons diagnosed with cancer during adolescence. Well into permanent survivorship an increase in symptoms of anxiety is shown and approximately a third of the participants report possible anxiety. The findings indicate the need for: studies designed to pinpoint the times of highest psychological risk, clinical follow-up focusing on psychological problems, and development of effective psychological interventions for survivors of adolescent cancer
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| 3. |
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| 4. |
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| 5. |
- Andersson, Håkan S., 1967-, et al.
(författare)
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The toxicity of ribbon worms: alpha-nemertides or tetrodotoxin, or both?
- 2016
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Ingår i: Planta Medica. - : Georg Thieme Verlag KG. - 0032-0943 .- 1439-0221. ; 82:Supplement 1
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The marine ribbon worms (nemerteans) are predators which capture their prey by everting a proboscis carrying a mixture of toxins which brings on rapid paralysis [1]. Moreover, ribbon worms have a thick layer of epidermal mucus of similar constitution. Tetrodotoxin (TTX) has been identified as one of these toxins [2]. The extreme toxicity of TTX (lethal by ingestion of 0.5-2 mg) is due to its ability to block voltage-gated sodium channels. Although several bacterial species (among these Vibrio sp.) have been linked to its synthesis, the biogenic origin and biosynthesis is unclear. One hypothesis is that TTX production occurs in a symbiotic relationship with its host, in this case the ribbon worm [3]. We have made significant effort to identify TTX in a setup for production through the cultivation of Vibrio alginolyticus in nutrient broth infused with mucus from the ribbon worm Lineus longissimus. Toxicity was demonstrated by fraction injections into shore crabs, but no TTX was found, and it could be shown conclusively that toxicity was unrelated to TTX and the Vibrio culture itself, and rather a constituent of the ribbon worm mucus [4]. The following studies led us to the discovery of a new class of peptides, the alpha-nemertides, in the mucus of the ribbon worms, which could be directly linked to the toxic effects. A literature review of the available evidence for TTX in ribbon worms show that the evidence in most cases are indirect, although notable exceptions exist. This points to the necessity to further investigate the presence and roles of TTX and alpha-nemertides in ribbon worms.
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| 6. |
- Arvidsson, Ida, et al.
(författare)
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Shiga toxin-induced complement-mediated hemolysis and release of complement-coated red blood cell-derived microvesicles in hemolytic uremic syndrome.
- 2015
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 194:5, s. 2309-2318
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Tidskriftsartikel (refereegranskat)abstract
- Shiga toxin (Stx)-producing Escherichia coli (STEC) cause hemolytic uremic syndrome (HUS). This study investigated whether Stx2 induces hemolysis and whether complement is involved in the hemolytic process. RBCs and/or RBC-derived microvesicles from patients with STEC-HUS (n = 25) were investigated for the presence of C3 and C9 by flow cytometry. Patients exhibited increased C3 deposition on RBCs compared with controls (p < 0.001), as well as high levels of C3- and C9-bearing RBC-derived microvesicles during the acute phase, which decreased after recovery. Stx2 bound to P1 (k) and P2 (k) phenotype RBCs, expressing high levels of the P(k) Ag (globotriaosylceramide), the known Stx receptor. Stx2 induced the release of hemoglobin and lactate dehydrogenase in whole blood, indicating hemolysis. Stx2-induced hemolysis was not demonstrated in the absence of plasma and was inhibited by heat inactivation, as well as by the terminal complement pathway Ab eculizumab, the purinergic P2 receptor antagonist suramin, and EDTA. In the presence of whole blood or plasma/serum, Stx2 induced the release of RBC-derived microvesicles coated with C5b-9, a process that was inhibited by EDTA, in the absence of factor B, and by purinergic P2 receptor antagonists. Thus, complement-coated RBC-derived microvesicles are elevated in HUS patients and induced in vitro by incubation of RBCs with Stx2, which also induced hemolysis. The role of complement in Stx2-mediated hemolysis was demonstrated by its occurrence only in the presence of plasma and its abrogation by heat inactivation, EDTA, and eculizumab. Complement activation on RBCs could play a role in the hemolytic process occurring during STEC-HUS.
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| 7. |
- Bergdahl, Gizem Ertürk, et al.
(författare)
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Bisphosphonate Ligand Mediated Ultrasensitive Capacitive Protein Sensor : Complementary Match of Supramolecular and Dynamic Chemistry
- 2019
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 43:2, s. 847-852
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Tidskriftsartikel (refereegranskat)abstract
- Modern healthcare demands rapid and accurate detection of proteins/enzymes at the ultratrace level. Herein we present a molecularly imprinted capacitive sensor for Trypsin, developed by microcontact imprinting. High affinity and selectivity was achieved by doping the prepolymerization mixture with a stoichiometric amount of methacrylamide-based bisphosphonate (BP) monomer. Taking advantage of the strong interaction of bisphosphonate with lysine/arginine residues on the surface of Trypsin, we have constructed a powerful polymeric sensor. The BP based sensor has the ability to recognize trypsin over other arginine-rich proteins, even in high ionic strength buffers with a sub-picomolar detection limit (pM). We believe that the combination of supramolecular chemistry, molecular imprinting and advanced instrumentation has a potential for future drug development and diagnostics that extends beyond biomolecular recognition.
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| 8. |
- Bergdahl, Gizem Ertürk, et al.
(författare)
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Capacitive Saccharide Sensor Based on Immobilized Phenylboronic Acid with Diol Specificity
- 2019
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Ingår i: Applied Biochemistry and Biotechnology. - : Springer Science and Business Media LLC. - 0273-2289 .- 1559-0291. ; 188:1, s. 124-137
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Tidskriftsartikel (refereegranskat)abstract
- A capacitive sensor for saccharide detection is described in this study. The detection is based on selective interaction between diols and aminophenylboronic acid (APBA) immobilized on a gold electrode. Glucose, fructose, and dextran (MW: 40 kDa) were tested with the system over wide concentration ranges (1.0 x 10−8 M - 1.0 x 10−3 M for glucose, 1.0 x 10−8 M - 1.0 x 10−2 M for fructose and 1.0 x 10−10 M - 1.0 x 10−5 M for dextran). The limits of detection (LODs) were 0.8 nM for glucose, 0.6 nM for fructose, and 13 pM for dextran. These data were comparable to the others reported previously. In order to demonstrate glycoprotein detection with the same sensor, human immunoglobulin G (IgG) as well as horseradish peroxidase were used as model analytes. The sensor responded to IgG in the concentration range of 1.0 x 10−13 M - 1.0 x 10−7 M with a LOD value of 16 fM. The performance of the assay of peroxidase was compared to a spectrophotometric assay by determining the enzymatic activity of a captured analyte. The results showed that the method might be useful for label-free, fast, and sensitive detection of saccharides as well as glycoproteins over a wide concentration range.
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| 9. |
- Bergdahl, Gizem Ertürk, et al.
(författare)
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Capacitive Sensor to Monitor Enzyme Activity by Following Degradation of Macromolecules in Real Time
- 2019
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Ingår i: Applied Biochemistry and Biotechnology. - : Springer Science and Business Media LLC. - 0273-2289 .- 1559-0291. ; 189, s. 374-383
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Tidskriftsartikel (refereegranskat)abstract
- A capacitive sensor was developed to analyze the presence and enzymatic activity of a model protease from standard solutions by following the degradation of the substrate in real time. The enzyme was chosen based on its specific digestion of the hinge region of immunoglobulin G (IgG). Real-time enzyme activity was monitored by measuring the change in capacitance (∆C) based on the release of IgG fragments after enzymatic digestion by the enzyme. The results indicated that the developed capacitive system might be used successfully for label-free and real-time monitoring of enzymatic activity of different enzymes in a sensitive, rapid, and inexpensive manner in biotechnological, environmental, and clinical applications.
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| 10. |
- Canfarotta, Francesco, et al.
(författare)
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A Novel Capacitive Sensor Based on Molecularly Imprinted Nanoparticles as Recognition Elements
- 2018
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Ingår i: Biosensors and Bioelectronics. - : Elsevier BV. - 0956-5663. ; , s. 108-114
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Tidskriftsartikel (refereegranskat)abstract
- Molecularly Imprinted Polymers (MIPs) are synthetic receptors capable of selective binding to their target (template) molecules and, hence, are used as recognition elements in assays and sensors as a replacement for relatively unstable enzymes and antibodies. Herein, we describe a manufacturing-friendly protocol for integration of MIP nanoparticles (nanoMIPs) with a (label-free) capacitive sensor. The nanoMIPs were produced by solid-phase synthesis for two templates with different sizes and properties, including a small molecule tetrahydrocannabinol (THC) and a protein (trypsin). NanoMIPs were deposited on the surface of the sensor and the change in capacitance (ΔC) upon binding of the target was measured. The significant improvement in the selectivity and limit of detection (one order of magnitude compared to previously used MIP microparticles) can be attributed to their increased surface-to-volume ratio and higher specificity of the nanoMIPs produced by the solid-phase method. The methodology described is also compatible with common sensor fabrication approaches, as opposed to methods involving in situ MIP polymerisation. The proposed sensor shows high selectivity, fast sensor response (45 min including injection, regeneration and re-equilibration with running buffer), and straightforward data analysis, which makes it viable for label-free monitoring in real-time. The set of targets assessed in this manuscript shows the general applicability of the biosensor platform.
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| 11. |
- Dugic, Izudin, 1962-, et al.
(författare)
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Non-metallic inclusion and their effect on fatigue strength for case-hardened carbon steel in gears
- 2018
-
Ingår i: TMS 2018 147th Annual Meeting & Exhibition Supplemental Proceedings. TMS 2018. - Cham : Springer. - 9783319725253 ; , s. 123-133
-
Konferensbidrag (refereegranskat)abstract
- Steel is a very essential structural material and its production worldwide has shown significant increase over the last years. In steels there always exist a large number of inclusions which can have a degrading effect on the fatigue properties. This study is focused on the link between the characteristics of non-metallic inclusions and how they affect fatigue strength of the standardized case-hardened carbon steel 20MnCr5 and a version of this steel with a more favorable inclusion distribution, a so-called Clean steel. For the evaluation of the mechanical properties the test result from rotary bending tests are compared and an improvement by 37.5% in fatigue strength can be noted between the different steels. The new performed ultrasonic tests illustrate the difference in the size of defects in materials with different manufacturing processes and degree of reduction. By studying international and European standards for non-destructive testing and investigation of alloy compounds, the current material specification can be adjusted. © The Minerals, Metals & Materials Society 2018.
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| 12. |
- Engdahl, Elin, et al.
(författare)
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Increased Serological Response Against Human Herpesvirus 6A Is Associated With Risk for Multiple Sclerosis
- 2019
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Ingår i: Frontiers in Immunology. - : Frontiers Media S.A.. - 1664-3224. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Human herpesvirus (HHV)-6A or HHV-6B involvement in multiple sclerosis (MS) etiology has remained controversial mainly due to the lack of serological methods that can distinguish the two viruses. A novel multiplex serological assay measuring IgG reactivity against the immediate-early protein 1 from HHV-6A (IE1A) and HHV-6B (IE1B) was used in a MS cohort (8,742 persons with MS and 7,215 matched controls), and a pre-MS cohort (478 individuals and 476 matched controls) to investigate this further. The IgG response against IE1A was positively associated with MS (OR = 1.55, p = 9 × 10-22), and increased risk of future MS (OR = 2.22, p = 2 × 10-5). An interaction was observed between IE1A and Epstein-Barr virus (EBV) antibody responses for MS risk (attributable proportion = 0.24, p = 6 × 10-6). In contrast, the IgG response against IE1B was negatively associated with MS (OR = 0.74, p = 6 × 10-11). The association did not differ between MS subtypes or vary with severity of disease. The genetic control of HHV-6A/B antibody responses were located to the Human Leukocyte Antigen (HLA) region and the strongest association for IE1A was the DRB1*13:01-DQA1*01:03-DQB1*06:03 haplotype while the main association for IE1B was DRB1*13:02-DQA1*01:02-DQB1*06:04. In conclusion a role for HHV-6A in MS etiology is supported by an increased serological response against HHV-6A IE1 protein, an interaction with EBV, and an association to HLA genes.
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| 13. |
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| 14. |
- Ertürk, Gizem, et al.
(författare)
-
A sensitive and real-time assay of trypsin by using molecular imprinting-based capacitive biosensor
- 2016
-
Ingår i: Biosensors and Bioelectronics. - : Elsevier BV. - 0956-5663. ; 86, s. 557-565
-
Tidskriftsartikel (refereegranskat)abstract
- Use of a highly sensitive, selective capacitive biosensor is reported for label-free, real-time, easy and rapid detection of trypsin by using the microcontact imprinting method. Real-time trypsin detection was performed with trypsin-imprinted (trypsin-MIP) capacitive electrodes using standard trypsin solutions in the concentration range of 1.0×10−13–1.0×10−7 M with a detection limit of 3.0×10−13 M. Selectivity and cross-reactivity of the system were tested by using competing proteins including chymotrypsin (chy), bovine serum albumin (BSA), lysozyme (lyz) and cytochrome c (cyt c) in singular and competitive manner and the selectivity of the system was determined with the selectivity coefficients of approximately 705.1, 6.5, 6.4 and 5.1 for chy, BSA, lyz and cyt c, respectively. The trypsin-MIP capacitive electrode was used for ~80 assays during 2 months and retained its binding property during all that time with a decrease of approximately 2.3% in the signal amplitude. In the last step, trypsin activity was measured by using Nα-Benzoyl-D, L-arginine 4-nitroanilide hydrochloride (BAPNA) as the substrate with spectrophotometer at 410 nm. The trypsin activity was measured as 9 mU/mL by spectrophotometer while the amount of captured enzyme calculated from the capacitive system was 7.9 mU/mL which shows the correlation between two methods. From the comparison it is obvious that the new method is an attractive alternative for assaying trypsin and the developed capacitive system might be used successfully to monitor label-free, real-time enzymatic activity of different proteases in a sensitive, rapid, cost-effective manner for different applications.
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| 15. |
- Ertürk, Gizem, et al.
(författare)
-
Bisphosphonate ligand mediated ultrasensitive capacitive protein sensor : complementary match of supramolecular and dynamic chemistry
- 2018
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 43:2, s. 847-852
-
Tidskriftsartikel (refereegranskat)abstract
- Modern healthcare demands rapid and accurate detection of proteins/enzymes at the ultratrace level. Herein we present a molecularly imprinted capacitive sensor for trypsin, developed by microcontact imprinting. High affinity and selectivity was achieved by doping the prepolymerization mixture with a stoichiometric amount of methacrylamide-based bisphosphonate (BP) monomer. Taking advantage of the specific interaction between bisphosphonate binding monomers and lysine/arginine residues on the surface of trypsin, we have constructed a powerful polymeric sensor. The BP based sensor has the ability to recognize trypsin over other arginine-rich proteins, even in high ionic strength buffers with a sub-picomolar detection limit (pM). We believe that the combination of supramolecular chemistry, molecular imprinting and advanced instrumentation has a potential for future drug development and diagnostics that extends beyond biomolecular recognition.
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| 16. |
- Ertürk, Gizem, et al.
(författare)
-
Highly sensitive detection and quantification of the secreted bacterial benevolence factor RoxP using a capacitive biosensor : A possible early detection system for oxidative skin diseases
- 2018
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:3
-
Tidskriftsartikel (refereegranskat)abstract
- The impact of the microbiota on our health is rapidly gaining interest. While several bacteria have been associated with disease, and others being indicated as having a probiotic effect, the individual biomolecules behind these alterations are often not known. A major problem in the study of these factors in vivo is their low abundance in complex environments. We recently identified the first secreted bacterial antioxidant protein, RoxP, from the skin commensal Propionibacterium acnes, suggesting its relevance for maintaining the redox homeostasis on the skin. In order to study the effect, and prevalence, of RoxP in vivo, a capacitive biosensor with a recognition surface based on molecular imprinting was used to detect RoxP on skin in vivo. In vitro analyses demonstrated the ability to detect and quantify RoxP in a concentration range of 1 x 10(-13) M to 1 x 10(-8) M from human skin swabs; with a limit of detection of 2.5 x 10(-19) M in buffer systems. Further, the biosensor was highly selective, not responding to any other secreted protein from P. acnes. Thus, it was possible to demonstrate the presence, and quantity, of RoxP on human skin. Therefore, the developed biosensor is a very promising tool for the detection of RoxP from clinical samples, offering a rapid, cost-effective and sensitive means of detecting low-abundant bacterial proteins in vivo in complex milieus.
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| 17. |
- Erturk, Gizem, et al.
(författare)
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Real-time prostate-specific antigen detection with prostate-specific antigen imprinted capacitive biosensors
- 2015
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 1873-4324 .- 0003-2670. ; 891, s. 120-129
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Tidskriftsartikel (refereegranskat)abstract
- Prostate specific antigen (PSA) is a valuable biomarker for early detection of prostate cancer, the third most common cancer in men. Ultrasensitive detection of PSA is crucial to screen the prostate cancer in an early stage and to detect the recurrence of the disease after treatment. In this report, microcontact-PSA imprinted (PSA-MIP) capacitive biosensor chip was developed for real-time, highly sensitive and selective detection of PSA. PSA-MIP electrodes were prepared in the presence of methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker via UV polymerization. Immobilized Anti-PSA antibodies on electrodes (Anti-PSA) for capacitance measurements were also prepared to compare the detection performances of both methods. The electrodes were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry (CV) and real-time PSA detection was performed with standard PSA solutions in the concentration range of 10 fg mL(-1) -100 ng mL(-1). The detection limits were found as 8.0 x 10(-5) ng mL(-1) (16 x 10(-17) M) and 6.0 x 10(-4) ng mL(-1) (12 x 10(-16) M) for PSA-MIP and Anti-PSA electrodes, respectively. Selectivity studies were performed against HSA and IgG and selectivity coefficients were calculated. PSA detection was also carried out from diluted human serum samples and finally, reproducibility of the electrodes was tested. The results are promising and show that when the sensitivity of the capacitive system is combined with the selectivity and reproducibility of the microcontact-imprinting procedure, the resulting system might be used successfully for real-time detection of various analytes even in very low concentrations. (C) 2015 Elsevier B.V. All rights reserved.
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| 18. |
- Foubert, Astrid, et al.
(författare)
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Antibody immobilization strategy for the development of a capacitive immunosensor detecting zearalenone
- 2019
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Ingår i: Talanta. - : Elsevier BV. - 0039-9140. ; 191, s. 202-208
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Tidskriftsartikel (refereegranskat)abstract
- A highly sensitive flow-injection capacitive immunosensor was developed for detection of the mycotoxin zearalenone (ZEN). Different strategies for immobilization of an anti-ZEN antibody on the surface of a gold electrode, i.e. polytyramine or self-assembled monolayers (SAMs) of 3-mercaptopropionic acid (3-MPA) and lipoic acid (LA), were used and their performances were compared. The LA- and 3-MPA-based systems showed broad linear ranges for ZEN determination, i.e. from 0.010 nM to 10 nM and from 0.020 nM to 10 nM, respectively. Under optimal conditions, the LA-based immunosensor was capable of performing up till 13 regeneration-interaction cycles (with use of glycine HCl, pH 2.4) with a limit of detection (LOD) of 0.0060 nM, equivalent to 1.9 pg mL−1. It also demonstrated a good inter-assay precision (RSD < 10%). However, the tyramine-based capacitive immunosensor showed a bad repeatability (only 4 regeneration-interaction cycles were possible) and inter-assay precision (RSD > 15%) which did not allow sensitive and precise measurements. The LA-based method was compared with a direct ELISA. These results demonstrated that the label-free developed capacitive immunosensor had a better sensitivity and shorter analysis time in comparison with the direct microwell-plate format.
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| 19. |
- Gunasekara, Saman Nimali, 1982-, et al.
(författare)
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The Experimental Phase Diagram Study of the Binary Polyols System Erythritol-Xylitol
- 2017
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 174, s. 248-262
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Tidskriftsartikel (refereegranskat)abstract
- A comprehensive phase diagram for the binary polyols system erythritol-xylitol has been mapped with a transparent characterization approach. Here, the phase equilibrium of the system has been studied experimentally using a combination of methods: Temperature-history (T-history), X-Ray Diffraction (XRD), and Field-Emission Scanning Electron Microscopy (FESEM), and linked to Tammann plots. Existing literature has previously shown the system to be a non-isomorphous type forming a simple eutectic, by combining experimental data with theoretical modelling. The present investigation shows that the system’s phase diagram is a partially isomorphous type forming a eutectic, but not a non-isomorphous type forming a simple eutectic. Here, the eutectic was found within 25-30 mol% erythritol and at 77 °C, which differs from the previous studies identifying the eutectic respectively at 25 or 36 mol% erythritol and at 82 °C. The reasons for the differences are hard to deduce since the research approach is not presented as fully transparent from the past studies. In the present study, only the temperature-composition plot of the first melting (of the two components in a physical mix, but not of a single blend) indicated the shape of a simple eutectic in a non-isomorphous system. The cycles after the first melting in contrast started from the real blend, and displayed eutectic and solid-solid phase changes in T-history. These were verified as forming solid solutions with XRD and FESEM. This eutectic melts at a temperature suitable for low-temperature solar heating, but displayed glass transition, supercooling, and thermally activated degradation, thus affecting its practical aspects as a PCM.
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| 20. |
- Gutierrez, Alvaro V R, et al.
(författare)
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Bioimprinting as a tool for the detection of aflatoxin B1 using a capacitive biosensor
- 2016
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Ingår i: Biotechnology Reports. - : Elsevier BV. - 2215-017X. ; 11, s. 12-17
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Tidskriftsartikel (refereegranskat)abstract
- A strategy for the detection of aflatoxin B1 using a capacitive biosensor has been studied. The use of proteins for the generation of sites with high specificity against aflatoxin B1 are produced via bioimprinting. This technique has become a tool for the detection of aflatoxin B1 using a capacitive biosensor. The results demonstrate the ability to generate specific interactions with aflatoxin B1 with a linear relation between signals registered and log concentration of the target aflatoxin in the concentration range of 3.2 × 10-6 to 3.2 × 10-9 M when using ovalbumin as framework for the bioimprinting.
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| 21. |
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| 22. |
- Idil, Neslihan, et al.
(författare)
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Whole cell based microcontact imprinted capacitive biosensor for the detection of Escherichia coli
- 2017
-
Ingår i: Biosensors and Bioelectronics. - : Elsevier BV. - 0956-5663. ; 87, s. 807-815
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a label-free, selective and sensitive microcontact imprinted capacitive biosensor was developed for the detection of Escherichia coli. The recognition of E. coli was successfully performed by this sensor prepared with the combination of microcontact imprinting method and capacitive biosensor technology. After preparation of bacterial stamps, microcontact-E. coli imprinted gold electrodes were generated using an amino acid based recognition element, N-methacryloyl-L-histidine methylester (MAH), 2-Hydroxyethyl methacrylate (HEMA) as monomers and ethyleneglycol dimethacrylate (EGDMA) as crosslinker under UV-polymerization. Real-time E. coli detection experiments were carried out within the range of 1.0×102–1.0×107 CFU/mL. The unique combination of these two techniques provides selective detection with a detection limit of 70 CFU/mL. The designed capacitive sensor has high selectivity and was able to distinguish E. coli when present together with competing bacterial strains which are known to have similar shape. In addition, the prepared sensor has the ability to detect E. coli with a recovery of 81–97% in e.g. river water.
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| 23. |
- Lebogang, Lesedi, et al.
(författare)
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Electrochemical flow-ELISA for rapid and sensitive determination of microcystin-LR using automated sequential injection system
- 2017
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 17:7
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Tidskriftsartikel (refereegranskat)abstract
- An amperometric immunoanalysis system based on monoclonal antibodies immobilized on Sepharose beads and packed into a micro-immunocolumn was developed for the quantification of microcystin-LR. Microcystin-LR (MCLR) was used as a reference microcystin variant. Inside the immunocolumn, free microcystins and microcystin-horseradish peroxidase (tracer) were sequentially captured by the immobilized antibodies, and the detection was performed electrochemically using Super AquaBlue ELISA substrate 2,2′ -azinobis(3-ethylbenzothiazoline-sulfonic acid) (ABTS). The ABTS•+ generated by enzymatic oxidation of ABTS was electrochemically determined at a carbon working electrode by applying a reduction potential set at 0.4 V versus Ag/AgCl reference electrode. The peak current intensity was inversely proportional to the amount of analyte bound to the immunocolumn. The amperometric flow-ELISA system, which was automatically controlled through the CapSenze™ (Lund, Sweden) computer software, enabled determination of MCLR as low as 0.01 µg/L. The assay time was very short (20 min for one assay cycle). In addition, the electrochemical signals were not significantly affected by possible interferences which could be present in the real samples. Along with the simplicity of automation, this makes the developed method a promising tool for use in water quality assessment.
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| 24. |
- Liu, Yanling, et al.
(författare)
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A capacitive DNA sensor-based test for simple and sensitive analysis of antibiotic resistance in field setting.
- 2015
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Ingår i: Biosensors & Bioelectronics. - : Elsevier BV. - 1873-4235 .- 0956-5663. ; 64, s. 255-259
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Tidskriftsartikel (refereegranskat)abstract
- To meet urgent needs for solving serious worldwide drug-resistance problems, a sensitive label-free capacitive sensor developed in our group was investigated as a tool to be applied in the field of antibiotic resistance genotyping, for instance the detection of ampicillin resistance gene (ampR). Proof-of-concept data demonstrated its detection sensitivity of pico-molar without any signal amplification step and a dynamic range of at least three orders of magnitude. The detection limits of less than 1pM for the single-stranded ampR oligonucleotide and 4pM for the double-stranded target can reliably be achieved after only 2.5min sample reaction. Reusability of the probe-functionalized disposable electrode was investigated by comparing different regeneration solutions; mix of 25mM NaOH/30% formamide was employed to regenerate the electrode for at least six cycles without significant loss of sensing ability. Assay is performed automatically and result is retrieved in 20min. The developed sensitive genotyping tool is expected to provide simple, fast and affordable screening for monitoring spread of antibiotic resistances, which is suitable for testing in field setting.
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| 25. |
- Ma, Fei, et al.
(författare)
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Ultrafast excited state dynamics of [Cr(CO)4(bpy)] : Revealing the relaxation between triplet charge-transfer states
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:25, s. 20507-20515
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Tidskriftsartikel (refereegranskat)abstract
- Ultrafast excited state dynamics of [Cr(CO)4(bpy)] upon metal-to-ligand charge-transfer (1MLCT) transition have been studied by pump-probe absorption spectroscopy in CH3CN, pyridine and CH2Cl2 solvents. Intersystem crossing (ISC) was found to be very fast (∼100 fs) and efficient, while the formation of the photoproduct with one axial CO dissociated is significantly less competitive, indicating a barrier along the dissociative coordinate. As a refinement of the previous dynamic model [I. R. Farrell, et al., J. Am. Chem. Soc., 1999, 121, 5296-5301], we show that a conventional downhill energy relaxation concept dominates the observed dynamics. Experimentally, we have identified the consecutive population of two triplet states as a result of triplet electronic relaxation convoluted with vibrational and solvent relaxation (the overall time is 2.7-6.9 ps depending on solvent), as well as the overall depopulation of the excited state through the lowest triplet state (57-84 ps). Adaptive excitation pulse shaping could not achieve optimization of the photoproduct quantum yield via re-distribution of only low-frequency vibrational modes during excitation, indicating that the two low-lying 1MLCT states, Cr(3d) → π∗bpy and Cr(3d) → π∗CO, are not coupled.
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| 26. |
- Mattiasson, Bo, et al.
(författare)
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Capacitive biosensors for ultra-sensitive assays
- 2016
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Ingår i: Trac. Trends in Analytical Chemistry. - : Elsevier BV. - 0165-9936. ; 79, s. 233-238
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Tidskriftsartikel (refereegranskat)abstract
- Capacitive binding assays have long been considered highly sensitive. The underlying method in such assays includes sending short potential pulses and then registering the current. However, with the introduction of current pulses and registration of potential responses, the stability improved significantly, leading to assays of extreme sensitivities. The new assaying technology has been applied in a range of affinity binding assays, from immunoassays via DNA base pairing to the use of molecularly imprinted polymers (MIPs). Overall, very good sensitivities have been recorded, and the MIPs exhibit high stability and reusability.
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| 27. |
- Sjöberg, Pia, et al.
(författare)
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Altered biventricular hemodynamic forces in patients with repaired tetralogy of Fallot and right ventricular volume overload because of pulmonary regurgitation
- 2018
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Ingår i: American Journal of Physiology - Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 315:6, s. 1691-1702
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Tidskriftsartikel (refereegranskat)abstract
- Intracardiac hemodynamic forces have been proposed to influence remodeling and be a marker of ventricular dysfunction. We aimed to quantify the hemodynamic forces in repaired tetralogy of Fallot (rToF) patients to further understand the pathophysiological mechanisms as this could be a potential marker for pulmonary valve replacement (PVR) in these patients. Patients with rToF and PR>20% (n=18) and healthy controls (n=15) underwent magnetic resonance imaging (MRI) including 4D-flow. A subset of patients (n=8) underwent PVR and MRI after surgery. Time-resolved hemodynamic forces were quantified using 4D-flow data and indexed to ventricular volume. Patients had higher systolic and diastolic left ventricular (LV) hemodynamic forces compared to controls in the lateral-septal/LVOT (p=0.011; p=0.0031) and inferior-anterior (p<0.0001; p<0.0001) directions, which are forces not aligned with blood flow. Forces did not change after PVR. Patients had higher RV diastolic forces compared to controls in the diaphragm-RVOT (p<0.001) and apical-basal (p=0.0017) directions. After PVR RV systolic forces in the diaphragm-RVOT direction decreased (p=0.039) to lower levels than in controls (p=0.0064). RV diastolic forces decreased in all directions (p=0.0078; p=0.0078; p=0.039) but were still higher than in controls in diaphragm-RVOT direction (p=0.046). In conclusion, patients with rToF and PR had LV hemodynamic forces less aligned with the intraventricular blood flow compared to controls and higher diastolic RV forces along the regurgitant flow direction in the RVOT and that of tricuspid inflow. Remaining force differences in LV and RV after PVR suggest that biventricular pumping does not normalize after surgery.
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| 28. |
- Strand, Malin, et al.
(författare)
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The Bacterial (Vibrio alginolyticus) Production of Tetrodotoxin in the Ribbon Worm Lineus longissimus-Just a False Positive?
- 2016
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Ingår i: Marine Drugs. - Basel : MDPI AG. - 1660-3397. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- We test previous claims that the bacteria Vibrio alginolyticus produces tetrodotoxin (TTX) when living in symbiosis with the nemertean Lineus longissimus by a setup with bacteria cultivation for TTX production. Toxicity experiments on the shore crab, Carcinus maenas, demonstrated the presence of a paralytic toxin, but evidence from LC-MS and electrophysiological measurements of voltage-gated sodium channel-dependent nerve conductance in maleWistar rat tissue showed conclusively that this effect did not originate from TTX. However, a compound of similar molecular weight was found, albeit apparently non-toxic, and with different LC retention time and MS/MS fragmentation pattern than those of TTX. We conclude that C. maenas paralysis and death likely emanate from a compound <5 kDa, and via a different mechanism of action than that of TTX. The similarity in mass between TTX and the Vibrio-produced low-molecular-weight, non-toxic compound invokes that thorough analysis is required when assessing TTX production. Based on our findings, we suggest that re-examination of some published claims of TTX production may be warranted.
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| 29. |
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| 30. |
- Zhou, Tao, 1988-
(författare)
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Integrated Experimental and Computational Study of Precipitation in Martensitic Steels
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Precipitation is a phase transformation process in metallic materials that significantlyaffects properties. The precipitation process that includes nucleation, growth andcoarsening of small particles can be tuned by alloying, deformation, thermal treatment.This opens opportunities for optimizing the properties of metallic materials bytailoring precipitation. An example of high-performance metallic materials withcontribution from precipitation is tempered martensitic steels. By means of highlydispersed nanoscale precipitates within the hierarchic martensitic microstructure,these steels achieve an excellent combination of ultra-high strength and hightoughness. With the objective of accelerating the development of these high-performance steels, an integrated computational materials engineering (ICME)approach, combining advanced characterization, physically based/semi-empiricalmodelling, theory and databases, is used in this thesis to develop computationallinkages from heat treatment to precipitation to strength.Two multicomponent steels, a Cu precipitation-hardened maraging stainless steel anda carbide-strengthened low alloy Cr – Mo – V martensitic steel, are studied in this thesisusing quantitative characterization and modelling. The results suggest that theprecipitation simulations using Langer-Schwartz-Kampmann-Wagner (LSKW)modelling have good agreements with the experiments and show promise for futurepredictive modelling to be used for materials design. The semi-empirical models forindividual strengthening mechanisms and an integration of the strengtheningmechanisms used in this work may also represent the trends in the yield strength offresh and tempered martensite, but it is difficult to predict the early yielding of freshmartensite and the correlation of hardness and strength. This indicates the need tofurther develop the models. Overall, this thesis shows that the ICME approach can beused to study and predict precipitation and precipitation-strengthening inmulticomponent steels. The applied approach differs from traditional trial-and-errortesting and has the potential to save time, money and resources in steel development.
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