| 1. |
- De Groot, P., et al.
(författare)
-
Donor metabolic characteristics drive effects of faecal microbiota transplantation on recipient insulin sensitivity, energy expenditure and intestinal transit time
- 2020
-
Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 69, s. 502-512
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Bariatric surgery improves glucose metabolism. Recent data suggest that faecal microbiota transplantation (FMT) using faeces from postbariatric surgery diet-induced obese mice in germ-free mice improves glucose metabolism and intestinal homeostasis. We here investigated whether allogenic FMT using faeces from post-Roux-en-Y gastric bypass donors (RYGB-D) compared with using faeces from metabolic syndrome donors (METS-D) has short-term effects on glucose metabolism, intestinal transit time and adipose tissue inflammation in treatment-naïve, obese, insulin-resistant male subjects. Design: Subjects with metabolic syndrome (n=22) received allogenic FMT either from RYGB-D or METS-D. Hepatic and peripheral insulin sensitivity as well as lipolysis were measured at baseline and 2 weeks after FMT by hyperinsulinaemic euglycaemic stable isotope (2H2-glucose and 2H5-glycerol) clamp. Secondary outcome parameters were changes in resting energy expenditure, intestinal transit time, faecal short-chain fatty acids (SCFA) and bile acids, and inflammatory markers in subcutaneous adipose tissue related to intestinal microbiota composition. Faecal SCFA, bile acids, glycaemic control and inflammatory parameters were also evaluated at 8 weeks. Results: We observed a significant decrease in insulin sensitivity 2 weeks after allogenic METS-D FMT (median rate of glucose disappearance: from 40.6 to 34.0 μmol/kg/min; p<0.01). Moreover, a trend (p=0.052) towards faster intestinal transit time following RYGB-D FMT was seen. Finally, we observed changes in faecal bile acids (increased lithocholic, deoxycholic and (iso)lithocholic acid after METS-D FMT), inflammatory markers (decreased adipose tissue chemokine ligand 2 (CCL2) gene expression and plasma CCL2 after RYGB-D FMT) and changes in several intestinal microbiota taxa. Conclusion: Allogenic FMT using METS-D decreases insulin sensitivity in metabolic syndrome recipients when compared with using post-RYGB-D. Further research is needed to delineate the role of donor characteristics in FMT efficacy in human insulin-resistant subjects. Trial registration number: NTR4327.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Boulo, S., et al.
(författare)
-
First amyloid β1-42 certified reference material for re-calibrating commercial immunoassays
- 2020
-
Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 16:11, s. 1493-1503
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Reference materials based on human cerebrospinal fluid were certified for the mass concentration of amyloid beta (Aβ)1-42 (Aβ42). They are intended to be used to calibrate diagnostic assays for Aβ42. Methods: The three certified reference materials (CRMs), ERM-DA480/IFCC, ERM-DA481/IFCC and ERM-DA482/IFCC, were prepared at three concentration levels and characterized using isotope dilution mass spectrometry methods. Roche, EUROIMMUN, and Fujirebio used the three CRMs to re-calibrate their immunoassays. Results: The certified Aβ42 mass concentrations in ERM-DA480/IFCC, ERM-DA481/IFCC, and ERM-DA482/IFCC are 0.45, 0.72, and 1.22μg/L, respectively, with expanded uncertainties (k=2) of 0.07, 0.11, and 0.18μg/L, respectively. Before re-calibration, a good correlation (Pearson's r>0.97), yet large biases, were observed between results from different commercial assays. After re-calibration the between-assay bias was reduced to<5%. Discussion: The Aβ42 CRMs can ensure the equivalence of results between methods and across platforms for the measurement of Aβ42. © 2020 the Alzheimer's Association
|
|
| 6. |
- White, H, et al.
(författare)
-
A certified plasmid reference material for the standardisation of BCR-ABL1 mRNA quantification by real time quantitative PCR.
- 2015
-
Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 29:2, s. 369-376
-
Tidskriftsartikel (refereegranskat)abstract
- Serial quantification of BCR-ABL1 mRNA is an important therapeutic indicator in chronic myeloid leukemia, but there is substantial variation in results reported by different laboratories. To improve comparability, an internationally accepted plasmid certified reference material (CRM) was developed according to ISO Guide 34:2009. Fragments of BCR-ABL1 (e14a2 mRNA fusion), BCR and GUSB transcripts were amplified and cloned into pUC18 to yield plasmid pIRMM0099. Six different linearised plasmid solutions were produced with the following copy number concentrations, assigned by digital PCR, and expanded uncertainties: 1.08±0.13 × 10(6), 1.08±0.11 × 10(5), 1.03±0.10 × 10(4), 1.02±0.09 × 10(3), 1.04±0.10 × 10(2) and 10.0±1.5 copies/μL. The certification of the material for the number of specific DNA fragments per plasmid, copy number concentration of the plasmid solutions and the assessment of inter-unit heterogeneity and stability were performed according to ISO Guide 35:2006. Two suitability studies performed by 63 BCR-ABL1 testing laboratories demonstrated that this set of 6 plasmid CRMs can help to standardise the numbers of measured transcripts of e14a2 BCR-ABL1 and three control genes; ABL1, BCR and GUSB. The set of 6 plasmid CRMs is distributed worldwide by the Institute for Reference Materials and Measurements (Belgium) and its authorised distributors (http://irmm.jrc.ec.europa.eu; CRM code ERM-AD623a-f).Leukemia accepted article preview online, 18 July 2014; doi:10.1038/leu.2014.217.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Isokääntä, Heidi, et al.
(författare)
-
Comparative Metabolomics and Microbiome Analysis of Ethanol versus OMNImet/gene•GUT Fecal Stabilization
- 2024
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 96:22, s. 8893-9304
-
Tidskriftsartikel (refereegranskat)abstract
- Metabolites from feces provide important insights into the functionality of the gut microbiome. As immediate freezing is not always feasible in gut microbiome studies, there is a need for sampling protocols that provide the stability of the fecal metabolome and microbiome at room temperature (RT). Here, we investigated the stability of various metabolites and the microbiome (16S rRNA) in feces collected in 95% ethanol (EtOH) and commercially available sample collection kits with specific preservatives OMNImet•GUT/OMNIgene•GUT. To simulate field-collection scenarios, the samples were stored at different temperatures at varying durations (24 h + 4 °C, 24 h RT, 36 h RT, 48 h RT, and 7 days RT) and compared to aliquots immediately frozen at -80 °C. We applied several targeted and untargeted metabolomics platforms to measure lipids, polar metabolites, endocannabinoids, short-chain fatty acids (SCFAs), and bile acids (BAs). We found that SCFAs in the nonstabilized samples increased over time, while a stable profile was recorded in sample aliquots stored in 95% EtOH and OMNImet•GUT. When comparing the metabolite levels between aliquots stored at room temperature and at +4 °C, we detected several changes in microbial metabolites, including multiple BAs and SCFAs. Taken together, we found that storing samples at RT and stabilizing them in 95% EtOH yielded metabolomic results comparable to those from flash freezing. We also found that the overall composition of the microbiome did not vary significantly between different storage types. However, notable differences were observed in the α diversity. Altogether, the stability of the metabolome and microbiome in 95% EtOH provided results similar to those of the validated commercial collection kits OMNImet•GUT and OMNIgene•GUT, respectively.
|
|
| 10. |
- John, Mike T, et al.
(författare)
-
Why Patients Visit Dentists : A Study in all World Health Organization Regions.
- 2020
-
Ingår i: Journal of Evidence-Based Dental Practice. - : Elsevier. - 1532-3382 .- 1532-3390. ; 20:3
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The dimensions of oral health-related quality of life (OHRQoL) Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact are the major areas where patients are impacted by oral diseases and dental interventions. The aim of this study was to evaluate whether dental patients' reasons to visit the dentist fit the 4 OHRQoL dimensions.METHODS: Dentists (N = 1580) from 32 countries participated in a web-based survey. For their patients with current oral health problems, dentists were asked whether these problems were related to teeth, mouth, and jaws' function, pain, appearance, or psychosocial impact or whether they do not fit the aforementioned 4 categories. Dentists were also asked about their patients who intended to prevent future oral health problems. For both patient groups, the proportions of oral health problems falling into the 4 OHRQoL dimensions were calculated.RESULTS: For every 100 dental patients with current oral health problems, 96 had problems related to teeth, mouth, and jaws' function, pain, appearance, or psychosocial impact. For every 100 dental patients who wanted to prevent future oral health problems, 92 wanted to prevent problems related to these 4 OHRQoL dimensions. Both numbers increased to at least 98 of 100 patients when experts analyzed dentists' explanations of why some oral health problems would not fit the four dimension. For the remaining 2 of 100 patients, none of the dentist-provided explanations suggested evidence against the OHRQoL dimensions as the concepts that capture dental patients' suffering.CONCLUSION: Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact capture dental patients' oral health problems worldwide. These 4 OHRQoL dimensions offer a psychometrically sound and practical framework for patient care and research, identifying what is important to dental patients.
|
|
| 11. |
- Kaiser, M., et al.
(författare)
-
Nucleation and growth of polycrystalline SiC
- 2014
-
Ingår i: IOP Conference Series. - : Institute of Physics Publishing (IOPP). ; 56:1, s. 012001-
-
Konferensbidrag (refereegranskat)abstract
- The nucleation and bulk growth of polycrystalline SiC in a 2 inch PVT setup using isostatic and pyrolytic graphite as substrates was studied. Textured nucleation occurs under near-thermal equilibrium conditions at the initial growth stage with hexagonal platelet shaped crystallites of 4H, 6H and 15R polytypes. It is found that pyrolytic graphite results in enhanced texturing of the nucleating gas species. Reducing the pressure leads to growth of the crystallites until a closed polycrystalline SiC layer containing voids with a rough surface is developed. Bulk growth was conducted at 35 mbar Ar pressure at 2250°C in diffusion limited mass transport regime generating a convex shaped growth form of the solid-gas interface leading to lateral expansion of virtually [001] oriented crystallites. Growth at 2350°C led to the stabilization of 6H polytypic grains. The micropipe density in the bulk strongly depends on the substrate used.
|
|
| 12. |
- Kaiser, M., et al.
(författare)
-
Polycrystalline SiC as source material for the growth of fluorescent SiC layers
- 2013
-
Ingår i: Silicon Carbide And Related Materials 2012. - : Trans Tech Publications Inc.. - 9783037856246 ; , s. 39-42
-
Konferensbidrag (refereegranskat)abstract
- Polycrystalline doped SiC act as source for fluorescent SiC. We have studied the growth of individual grains with different polytypes in the source material. We show an evolution and orientation of grains of different polytypes in polycrystalline SiC ingots grown by the Physical Vapor Transport method. The grain influence on the growth rate of fluorescent SiC layers grown by a sublimation epitaxial process is discussed in respect of surface kinetics.
|
|
| 13. |
- Koutsouflakis, Emmanouil, et al.
(författare)
-
Metamagnetic transition and a loss of magnetic hysteresis caused by electron trapping in monolayers of single-molecule magnet Tb2@C79N
- 2022
-
Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 14:27, s. 9877-9892
-
Tidskriftsartikel (refereegranskat)abstract
- Realization of stable spin states in surface-supported magnetic molecules is crucial for their applications in molecular spintronics, memory storage or quantum information processing. In this work, we studied the surface magnetism of dimetallo-azafullerene Tb2@C79N, showing a broad magnetic hysteresis in a bulk form. Surprisingly, monolayers of Tb2@C79N exhibited a completely different behavior, with the prevalence of a ground state with antiferromagnetic coupling at low magnetic field and a metamagnetic transition in the magnetic field of 2.5-4 T. Monolayers of Tb2@C79N were deposited onto Cu(111) and Au(111) by evaporation in ultra-high vacuum conditions, and their topography and electronic structure were characterized by scanning tunneling microscopy and spectroscopy (STM/STS). X-ray photoelectron spectroscopy (XPS), in combination with DFT studies, revealed that the nitrogen atom of the azafullerene cage tends to avoid metallic surfaces. Magnetic properties of the (sub)monolayers were then studied by X-ray magnetic circular dichroism (XMCD) at the Tb-M4,5 absorption edge. While in bulk powder samples Tb2@C79N behaves as a single-molecule magnet with ferromagnetically coupled magnetic moments and blocking of magnetization at 28 K, its monolayers exhibited a different ground state with antiferromagnetic coupling of Tb magnetic moments. To understand if this unexpected behavior is caused by a strong hybridization of fullerenes with metallic substrates, XMCD measurements were also performed for Tb2@C79N adsorbed on h-BN|Rh(111) and MgO|Ag(100). The co-existence of two forms of Tb2@C79N was found on these substrates as well, but magnetization curves showed narrow magnetic hysteresis detectable up to 25 K. The non-magnetic state of Tb2@C79N in monolayers is assigned to anionic Tb2@C79N− species with doubly-occupied Tb-Tb bonding orbital and antiferromagnetic coupling of the Tb moments. A charge transfer from the substrate or trapping of secondary electrons are discussed as a plausible origin of these species.
|
|
| 14. |
- Krylov, Denis S., et al.
(författare)
-
Substrate-Independent Magnetic Bistability in Monolayers of the Single-Molecule Magnet Dy2ScN@C80 on Metals and Insulators
- 2020
-
Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 59:14, s. 5756-5764
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic hysteresis is demonstrated for monolayers of the single-molecule magnet (SMM) Dy2ScN@C80 deposited on Au(111), Ag(100), and MgO|Ag(100) surfaces by vacuum sublimation. The topography and electronic structure of Dy2ScN@C80 adsorbed on Au(111) were studied by STM. X-ray magnetic CD studies show that the Dy2ScN@C80 monolayers exhibit similarly broad magnetic hysteresis independent on the substrate used, but the orientation of the Dy2ScN cluster depends strongly on the surface. DFT calculations show that the extent of the electronic interaction of the fullerene molecules with the surface is increasing dramatically from MgO to Au(111) and Ag(100). However, the charge redistribution at the fullerene-surface interface is fully absorbed by the carbon cage, leaving the state of the endohedral cluster intact. This Faraday cage effect of the fullerene preserves the magnetic bistability of fullerene-SMMs on conducting substrates and facilitates their application in molecular spintronics.
|
|
| 15. |
- Kuhlmann, Julia, et al.
(författare)
-
CSF Aβ1-42 - an excellent but complicated Alzheimer's biomarker - a route to standardisation.
- 2017
-
Ingår i: Clinica chimica acta; international journal of clinical chemistry. - : Elsevier BV. - 1873-3492. ; 467, s. 27-33
-
Tidskriftsartikel (refereegranskat)abstract
- The 42 amino acid form of amyloid β (Aβ1-42) in cerebrospinal fluid (CSF) has been widely accepted as a central biomarker for Alzheimer's disease. Several immunoassays for CSF Aβ1-42 are commercially available, but can suffer from between laboratory and batch-to-batch variability as well as lack of standardisation across assays. As a consequence, no general cut-off values have been established for a specific context of use (e.g., clinical diagnostics) and selection of individuals for enrolment in clinical trials (patient stratification) remains challenging. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has initiated a working group for CSF proteins (WG-CSF) to facilitate standardisation of CSF Aβ1-42 measurement results. The efforts of the IFCC WG-CSF include the development of certified reference materials (CRMs) and reference measurement procedures (RMPs) for key biomarkers. Two candidate RMPs for quantification of Aβ1-42 in CSF based on liquid chromatography tandem mass spectrometry have been developed and tested in two ring trials. Furthermore, two commutability studies including native CSF pools, artificial CSF and spiked materials have been completed. On the basis of these studies, human CSF pools containing only endogenous Aβ1-42 at three concentrations were selected as the format for future CRMs that are now being processed.
|
|
| 16. |
- Moore, E. E., et al.
(författare)
-
Association of Aortic Stiffness With Biomarkers of Neuroinflammation, Synaptic Dysfunction, and Neurodegeneration
- 2021
-
Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 97:4
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To test the hypothesis that increased aortic stiffening is associated with greater CSF evidence of core Alzheimer disease pathology (beta-amyloid [A beta], phosphorylated tau [p-tau]), neurodegeneration (total tau [t-tau]), synaptic dysfunction (neurogranin), neuroaxonal injury (neurofilament light [NFL]), and neuroinflammation (YKL-40, soluble triggering receptor expressed on myeloid cells 2 [sTREM2]), we analyzed pulse wave velocity (PWV) data and CSF data among older adults. Methods Participants free of stroke and dementia from the Vanderbilt Memory and Aging Project, an observational community-based study, underwent cardiac magnetic resonance to assess aortic PWV (meters per second) and lumbar puncture to obtain CSF. Linear regressions related aortic PWV to CSF A beta, p-tau, t-tau, neurogranin, NFL, YKL-40, and sTREM2 concentrations after adjustment for age, race/ethnicity, education, apolipoprotein (APOE) epsilon 4 status, Framingham Stroke Risk Profile, and cognitive diagnosis. Models were repeated testing PWV interactions with age, diagnosis, APOE epsilon 4, and hypertension on each biomarker. Results One hundred forty-six participants were examined (age 72 +/- 6 years). Aortic PWV interacted with age on p-tau (beta = 0.31, p = 0.04), t-tau, (beta = 2.67, p = 0.05), neurogranin (beta = 0.94, p = 0.04), and sTREM2 (beta = 20.4, p = 0.05). Among participants >73 years of age, higher aortic PWV related to higher p-tau (beta = 2.4, p = 0.03), t-tau (beta = 19.3, p = 0.05), neurogranin (beta = 8.4, p = 0.01), and YKL-40 concentrations (beta = 7,880, p = 0.005). Aortic PWV had modest interactions with diagnosis on neurogranin (beta = -10.76, p = 0.03) and hypertension status on YKL-40 (beta = 18,020, p < 0.001). Conclusions Among our oldest participants, >= 74 years of age, greater aortic stiffening is associated with in vivo biomarker evidence of neuroinflammation, tau phosphorylation, synaptic dysfunction, and neurodegeneration, but not amyloidosis. Central arterial stiffening may lead to cumulative cerebral microcirculatory damage and reduced blood flow delivery to tissue, resulting in neuroinflammation and neurodegeneration in more advanced age.
|
|
| 17. |
- Patel, G.N., et al.
(författare)
-
An asynchronous architecture for modeling intersegmental neural communication
- 2006
-
Ingår i: IEEE Transactions on Very Large Scale Integration (vlsi) Systems. - 1063-8210 .- 1557-9999. ; 14:2, s. 97-111
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents an asynchronous VLSI architecture for modeling the oscillatory patterns seen in segmented biological systems. The architecture emulates the intersegmental synaptic connectivity observed in these biological systems. The communications network uses address-event representation (AER), a common neuromorphic protocol for data transmission. The asynchronous circuits are synthesized using communicating hardware processes (CHP) procedures. The architecture is scalable, supports multichip communication, and operates independent of the type of silicon neuron (spiking or burst envelopes). A 16-segment prototype system was developed, tested, and implemented, data from this system are presented. © 2006 IEEE.
|
|
| 18. |
- Schimmel, S., et al.
(författare)
-
Step-flow growth of fluorescent 4H-SiC layers on 4 degree off-axis substrates
- 2013
-
Ingår i: Silicon Carbide and Related Materials 2012. - : Trans Tech Publications Inc.. - 9783037856246 ; , s. 185-188
-
Konferensbidrag (refereegranskat)abstract
- Homoepitaxial layers of fluorescent 4H-SiC were grown on 4 degree off-axis substrates by sublimation epitaxy. Luminescence in the green spectral range was obtained by co-doping with nitrogen and boron utilizing donor-acceptor pair luminescence. This concept opens possibilities to explore green light emitting diodes using a new materials platform.
|
|
| 19. |
- Schimmel, S., et al.
(författare)
-
The role of defects in fluorescent silicon carbide layers grown by sublimation epitaxy
- 2014
-
Ingår i: IOP Conference Series. - : Institute of Physics Publishing (IOPP). ; 56:1, s. 012002-
-
Konferensbidrag (refereegranskat)abstract
- Donor-acceptor co-doped SiC is a promising light converter for novel monolithic all-semiconductor white LEDs due to its broad-band donor-acceptor pair luminescence and potentially high internal quantum efficiency. Besides sufficiently high doping concentrations in an appropriate ratio yielding short radiative lifetimes, long nonradiative lifetimes are crucial for efficient light conversion. The impact of different types of defects is studied by characterizing fluorescent silicon carbide layers with regard to photoluminescence intensity, homogeneity and efficiency taking into account dislocation density and distribution. Different doping concentrations and variations in gas phase composition and pressure are investigated.
|
|
| 20. |
- Sekulić, Stella, et al.
(författare)
-
Frequency of four-dimensional oral health problems across dental fields – A comparative survey of Slovenian and international dentists
- 2021
-
Ingår i: Zdravstveno Varstvo. - : National Institute of Public Health Slovenia. - 0351-0026 .- 1854-2476. ; 60:4, s. 210-220
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To compare the frequency of patients' oral health problems and prevention needs among Slovenian and international dentists with the aim to validate the four oral health-related quality of life (OHRQoL) dimensions across six clinical dental fields in all World Health Organization (WHO) regions. Methods: An anonymous electronic survey in the English language was designed using Qualtrics software. A probability sampling for Slovenia and a convenience sampling strategy for dentist recruitment was applied for 31 countries. Dentists engaged in six dental fields were asked to categorize their patients' oral health problems and prevention needs into the four OHRQoL dimensions (Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact). Proportions of patients' problems and prevention needs were calculated together with the significance of Slovenian and international dentists' differences based on dental fields and WHO regions. Results: Dentists (n=1,580) from 32 countries completed the survey. There were 223 Slovenian dentists (females: 68%) with a mean age (SD) of 41 (10.6) years and 1,358 international dentists (females: 51%) with a mean age (SD) of 38 (10.4). Pain-related problems and prevention needs were the most prevalent among all six dental fields reported by dentists; Slovenian (37%) and 31 countries (45%). According to Cohen, differences between Slovenia, the broader European Region, and 31 countries were considered non-significant (<0.1). Conclusion: According to the dentists' responses, the frequency of patients' oral health problems and prevention needs are proportionate between Slovenia and 31 countries, regionally and globally. The four OHRQoL dimensions can be considered universal across all dental fields.
|
|
