| 107471. |
- Kolesnichenko, Pavel V., et al.
(författare)
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Fully symmetric dispersionless stable transmission-grating Michelson interferometer
- 2020
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Ingår i: Optics Express. - 1094-4087. ; 28:25, s. 37752-37757
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Tidskriftsartikel (refereegranskat)abstract
- Michelson interferometers have been routinely used in various applications ranging from testing optical components to interferometric time-resolved spectroscopy measurements. Traditionally, plate beamsplitters are employed to redistribute radiation between the two arms of an interferometer. However, such an interferometer is susceptible to relative phase fluctuations between the two arms resulting from vibrations of the beamsplitter. This drawback is circumvented in diffraction-grating-based interferometers, which are especially beneficial in applications where highly stable delays between the replica beams are required. In the vast majority of grating-based interferometers, reflective diffraction gratings are used as beamsplitters. Their diffraction efficiency, however, is strongly wavelength dependent. Therefore transmission-grating interferometers can be advantageous for spectroscopy methods, since they can provide high diffraction efficiency over a wide spectral range. Here, we present and characterize a transmission grating-based Michelson interferometer, which is practically dispersion-free, has intrinsically high symmetry and stability and moderate throughput efficiency, and is promising for a wide range of applications.
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| 107472. |
- Kolesnichenko, Pavel V., et al.
(författare)
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Neural-network-powered pulse reconstruction from one-dimensional interferometric correlation traces
- 2023
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Ingår i: Optics Express. - 1094-4087. ; 31:7, s. 11806-11819
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Tidskriftsartikel (refereegranskat)abstract
- Any ultrafast optical spectroscopy experiment is usually accompanied by the necessary routine of ultrashort-pulse characterization. The majority of pulse characterization approaches solve either a one-dimensional (e.g., via interferometry) or a two-dimensional (e.g., via frequency-resolved measurements) problem. Solution of the two-dimensional pulse-retrieval problem is generally more consistent due to the problem’s over-determined nature. In contrast, the one-dimensional pulse-retrieval problem, unless constraints are added, is impossible to solve unambiguously as ultimately imposed by the fundamental theorem of algebra. In cases where additional constraints are involved, the one-dimensional problem may be possible to solve, however, existing iterative algorithms lack generality, and often stagnate for complicated pulse shapes. Here we use a deep neural network to unambiguously solve a constrained one-dimensional pulse-retrieval problem and show the potential of fast, reliable and complete pulse characterization using interferometric correlation time traces determined by the pulses with partial spectral overlap.
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| 107473. |
- Kolesnichenko, Pavel V., et al.
(författare)
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Viking Spectrophotometer : A Home-Built, Simple, and Cost-Efficient Absorption and Fluorescence Spectrophotometer for Education in Chemistry
- 2023
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Ingår i: Journal of Chemical Education. - : American Chemical Society (ACS). - 0021-9584 .- 1938-1328. ; 100:3, s. 1128-1137
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Tidskriftsartikel (refereegranskat)abstract
- Investigating the optical properties of various chemical compounds using UV-vis spectrophotometers is an essential part of education in chemistry. However, commercial spectrophotometers are usually treated as "magic black boxes", where the dominant majority of optical elements are hidden "under the hood". This often limits understanding of the mechanisms behind the generation of spectral curves, which in turn may impede the ability to understand the limitations of the applied method and, in some cases, interpret the acquired data. In addition, the study of optical emission phenomena using fluorescence spectrophotometers is seldom implemented in educational laboratories due to the practical challenges and costs of the devices, which severely limit pedagogic access to this topic. For students to be more confident with these two basic spectroscopy techniques, we have developed a laboratory kit that provides a multifaceted learning experience. Starting with a basic exploration of an instrument assembly, it teaches, for example, such technical concepts as spectral resolution and detection sensitivity. More fundamentally, it enables deeper learning of the Beer-Lambert law and the notion of Stokes shift. The spectrophotometer is built from cost-efficient materials and is easily scalable, making it affordable for many educational laboratories. Due to a modular design, it is adaptable to various levels of education and has been successfully applied during high school-, undergraduate-, and graduate-level classes.
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| 107474. |
- Koletzko, Sibylle, et al.
(författare)
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Caesarean Section on The Risk of Celiac Disease in the Offspring : The Teddy Study
- 2018
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Ingår i: Journal of Pediatric Gastroenterology and Nutrition. - 0277-2116. ; 66:3, s. 417-424
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:: Caesarean section (C-section) is associated with various immune-mediated diseases in the offspring. We investigated the relationship between mode of delivery and celiac disease (CD) and CD autoimmunity (CDA) in a multinational birth cohort. METHODS:: From 2004 to 2010 infants from the general population who tested positive for HLA DR3-DQ2 or DR4-DQ8 were enrolled in The Environmental Determinants for Diabetes in the Young (TEDDY) study. Children were annually screened for transglutaminase autoantibodies, if positive re-tested after 3–6 months and those persistently positive defined as CDA. Associations of C-section with maternal (age, education level, parity, pre-pregnancy weight, diabetes, smoking, weight gain during pregnancy) and child characteristics (gestational age, birth weight) were examined by Fisherʼs exact test or Wilcoxon rank-sum test. Hazard ratios (HRs) for CDA or CD were calculated by Cox proportional hazard regression models. RESULTS:: Of 6,087 analyzed singletons 1600 (26%) were born by C-section (Germany 38%, US 37%, Finland 18%, Sweden 16%), the remaining vaginally without instrumental support; 979 (16%) had developed CDA and 343 (6%) CD. C-section was associated with lower risk for CDA (HR?=?0.85, [95% CI 0.73, 0.99], p?=?0.032) and CD (HR?=?0.75, [95% CI 0.58, 0.98], p?=?0.034). After adjusting for country, sex, HLA-genotype, CD in family, maternal education and breastfeeding duration, significance was lost for CDA (HR?=?0.91, [95% CI 0.78, 1.06], p?=?0.20) and CD (HR?=?0.85, [95% CI 0.65, 1.11], p?=?0.24). Pre-surgical ruptured membranes had no influence on CDA or CD development. CONCLUSION:: C-section is not associated with increased risk for CDA or CD in the offspring.
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| 107475. |
- Koley, Biplab, et al.
(författare)
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Structure and stability of γ1-AuZn2.1 : A γ-brass-related complex phase in the Au-Zn System
- 2020
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Ingår i: Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials. - 2052-5192. ; 76, s. 1109-1116
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Tidskriftsartikel (refereegranskat)abstract
- γ1-AuZn2.1 in the Au-Zn binary system has been synthesized and its structure analyzed by single-crystal X-ray diffraction. It crystallizes in the trigonal space group P31m (No. 157) with ∼227 atoms per unit cell and represents a 3a × 3a × c superstructure of rhombohedrally distorted γ-Au5-x Zn8+y. The structure is largely tetrahedrally closed packed. The formation of γ1-AuZn2.1 can be understood within the framework of a Hume-Rothery stabilization mechanism with a valence electron concentration of 1.68 e/a (valence electrons per atom).
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| 107476. |
- Kolijn, P. Martijn, et al.
(författare)
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High-risk subtypes of chronic lymphocytic leukemia are detectable as early as 16 years prior to diagnosis
- 2022
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 139:10, s. 1557-1563
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Tidskriftsartikel (refereegranskat)abstract
- Chronic lymphocytic leukemia (CLL) is preceded by monoclonal B-cell lymphocytosis (MBL), a CLL precursor state with a prevalence of up to 12% in aged individuals; however, the duration of MBL and the mechanisms of its evolution to CLL remain largely unknown. In this study, we sequenced the B-cell receptor (BcR) immunoglobulin heavy chain (IGH) gene repertoire of 124 patients with CLL and 118 matched controls in blood samples taken up to 22 years prior to diagnosis. Significant skewing in the BcR IGH gene repertoire was detected in the majority of patients, even before the occurrence of lymphocytosis and irrespective of the clonotypic IGH variable gene somatic hypermutation status. Furthermore, we identified dominant clonotypes belonging to major stereotyped subsets associated with poor prognosis up to 16 years before diagnosis in 14 patients with CLL. In 22 patients with longitudinal samples, the skewing of the BcR IGH gene repertoire increased significantly over time to diagnosis or remained stable at high levels. For 14 of 16 patients with available samples at diagnosis, the CLL clonotype was already present in the prediagnostic samples. Overall, our data indicate that the preclinical phase of CLL could be longer than previously thought, even in adverse-prognostic cases.
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| 107477. |
- Kõljalg, Urmas, et al.
(författare)
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UNITE: a database providing web-based methods for the molecular identification of ectomycorrhizal fungi
- 2005
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 166:3, s. 1063-1068
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Tidskriftsartikel (refereegranskat)abstract
- Identification of ectomycorrhizal (ECM) fungi is often achieved through comparisons of ribosomal DNA internal transcribed spacer (ITS) sequences with accessioned sequences deposited in public databases. A major problem encountered is that annotation of the sequences in these databases is not always complete or trustworthy. In order to overcome this deficiency, we report on UNITE, an open-access database. UNITE comprises well annotated fungal ITS sequences from well defined herbarium specimens that include full herbarium reference identification data, collector/source and ecological data. At present UNITE contains 758 ITS sequences from 455 species and 67 genera of ECM fungi. UNITE can be searched by taxon name, via sequence similarity using BLAST n, and via phylogenetic sequence identification using galaxie. Following implementation, galaxie performs a phylogenetic analysis of the query sequence after alignment either to pre-existing generic alignments, or to matches retrieved from a BLAST search on the UNITE data. It should be noted that the current version of UNITE is dedicated to the reliable identification of ECM fungi. The UNITE database is accessible through the URLhttp://unite.zbi.ee.
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| 107478. |
- Koljonen, Virve, et al.
(författare)
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Joint occurrence of Merkel cell carcinoma and non-Hodgkin lymphomas in four Nordic countries
- 2015
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Ingår i: Leukemia & Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 56:12, s. 3315-3319
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to assess the reciprocal association between non-Hodgkin lymphoma (NHL) and Merkel cell carcinoma (MCC) using the data of four Nordic Cancer Registries. Data for this study were drawn from the Danish, Finnish, Norwegian, and Swedish cancer registries. Standardized incidence ratios (SIRs) for MCC among NHL patients, and for NHL among MCC patients, were calculated. There were 109 838 individuals with NHL and 1411 individuals with MCC, of which 28 had joint occurrence of NHL and MCC. In 18 cases, NHL was diagnosed first, and in 10 cases, MCC was diagnosed first. The SIR for MCC after NHL was 4.34 (95% confidence interval 2.57-6.85). The SIR for NHL after MCC was 3.13 (1.50-5.77). Although the absolute frequency of joint occurrence of MCC and NHL is low, individuals suffering from one of the cancer forms have an increased risk of the other.
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| 107479. |
- Kolkova, K, et al.
(författare)
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Distinct roles of PKC isoforms in NCAM-mediated neurite outgrowth
- 2005
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 92:4, s. 886-894
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Tidskriftsartikel (refereegranskat)abstract
- The role of protein kinase C (PKC) isoforms in the neural cell adhesion molecule (NCAM)-mediated neurite outgrowth was tested using a co-culture system consisting of fibroblasts with or without NCAM expression upon which either primary cerebellar granular neurones (CGN) or pheochromocytoma (PC12-E2) cells were grown. The latter transiently expressed various PKC isoforms and domains derived from selected PKCs. PKC inhibitors of various specificity inhibited NCAM-stimulated neuritogenesis from CGN, indicating that PKC is involved in this process. Moreover, stimulation by the NCAM-mimetic peptide, C3d, elicited phosphorylation of PKC in CGN. Expression of kinase-deficient forms of PKCalpha, betaI and betaII blocked NCAM-mediated neurite extension, but had no effect on nerve growth factor (NGF)-mediated neurite outgrowth. Expression of two PKCepsilon constructs: (i) a fragment from PKCepsilon encompassing the pseudosubstrate, the C1a domain (including the actin-binding site, ABS), and parts of the V3 region, or (ii) the PKCepsilon-specific ABS blocked NCAM-mediated neurite extension in both cases. These two constructs also partially inhibited NGF-stimulated neuritogenesis indicating that PKCepsilon is a positive regulator of both NCAM- and NGF-mediated differentiation. We suggest that PKCepsilon is a common downstream mediator for several neuritogenic factors, whereas one or more conventional PKCs are specifically involved in NCAM-stimulated neurite outgrowth.
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| 107480. |
- Kolkova, Zuzana, et al.
(författare)
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G protein-coupled estrogen receptor 1 (GPER, GPR 30) in normal human endometrium and early pregnancy decidua.
- 2010
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Ingår i: Molecular Human Reproduction. - : Oxford University Press (OUP). - 1460-2407 .- 1360-9947. ; 16:10, s. 743-751
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Tidskriftsartikel (refereegranskat)abstract
- The recently identified trans-membrane G protein-coupled estrogen receptor 1 (GPER, GPR30) has been implicated in rapid non-genomic effects of estrogens. This focusses on expression and localization of GPER mRNA and protein in normal cyclic endometrium and early pregnancy decidua. Real-time PCR, Western blotting, in situ hybridization, and immuno-histochemistry were used. Endometrial expression of GPER mRNA was lower in the secretory phase than in the proliferative phase , and even lower in the decidua. The expression pattern was similar to that of ERalpha mRNA, but different from that of ERss mRNA. Western blot detected GPER protein as a 54 kDa band in all endometrial and decidual samples. In contrast to the mRNA, GPER protein did not show cyclic variations. Apparently, a lower amount of mRNA is sufficient to maintain protein levels in the secretory phase. GPER mRNA was predominantly localized in the epithelium of mid and late proliferative phase endometrium, whereas expression in early proliferative and secretory glands could not be distinguished from the diffuse stromal signal, which was present throughout the cycle. Immuno-staining for GPER was stronger in glandular and luminal epithelium than in the stroma throughout the cycle. The cyclic variations of GPER mRNA obviously relate to strong epithelial expression in the proliferative phase, and the expression pattern suggests regulation by ovarian steroids. GPER protein is present in endometrial tissue throughout the cycle, and the epithelial localization suggests potential functions during sperm migration at midcycle as well as decidualization and blastocyst implantation in the mid-secretory phase.
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