| 1. |
- Zamora, Juan Carlos, et al.
(author)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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In: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Journal article (peer-reviewed)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 2. |
- Bocchetta, Martina, et al.
(author)
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The use of biomarkers for the etiologic diagnosis of MCI in Europe: An EADC survey.
- 2015
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In: Alzheimer's & Dementia. - : Wiley. - 1552-5279 .- 1552-5260. ; 11:2, s. 195-206
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Journal article (peer-reviewed)abstract
- We investigated the use of Alzheimer's disease (AD) biomarkers in European Alzheimer's Disease Consortium centers and assessed their perceived usefulness for the etiologic diagnosis of mild cognitive impairment (MCI). We surveyed availability, frequency of use, and confidence in diagnostic usefulness of markers of brain amyloidosis (amyloid positron emission tomography [PET], cerebrospinal fluid [CSF] Aβ42) and neurodegeneration (medial temporal atrophy [MTA] on MR, fluorodeoxyglucose positron emission tomography [FDG-PET], CSF tau). The most frequently used biomarker is visually rated MTA (75% of the 37 responders reported using it "always/frequently") followed by CSF markers (22%), FDG-PET (16%), and amyloid-PET (3%). Only 45% of responders perceive MTA as contributing to diagnostic confidence, where the contribution was rated as "moderate". Seventy-nine percent of responders felt "very/extremely" comfortable delivering a diagnosis of MCI due to AD when both amyloid and neuronal injury biomarkers were abnormal (P < .02 versus any individual biomarker). Responders largely agreed that a combination of amyloidosis and neuronal injury biomarkers was a strongly indicative AD signature.
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| 3. |
- Domeij, Martin, et al.
(author)
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Dynamic avalanche in Si power diodes and impact ionization at the nn(+) junction
- 2000
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In: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 44:3, s. 477-485
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Journal article (peer-reviewed)abstract
- The reverse recovery failure limit was measured with an optical technique for power diodes which sustain high levels of dynamic avalanche. Measurements and simulations indicate that these diodes withstand dynamic avalanche at the pn-junction and eventually fail as a result of a strongly inhomogeneous current distribution caused by the onset of impact ionisation at the diode nn(+) junction - a mechanism similar to the reverse bias second breakdown of bipolar transistors.
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| 4. |
- Domeij, Martin, et al.
(author)
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Stable dynamic avalanche in Si power diodes
- 1999
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 74:21, s. 3170-3172
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Journal article (peer-reviewed)abstract
- A stable dynamic avalanche at a maximum power density of about 2.4 MW/cm(2) was measured in small areas of 3.3 kV Si power diodes, using an optical measurement technique, and very good dynamic ruggedness was verified in a conventional turn-off measurement. Device simulations of a diode with a shallow n(+) emitter indicate that impact ionization at the nn(+) junction can result in negative differential resistance (NDR) and current filamentation, whereas a deep n(+) emitter in the experimentally studied diode suppresses NDR. It is, therefore, proposed that the deep n(+) emitter is important for the stable dynamic avalanche.
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| 5. |
- Ekeberg, Tomas, 1983-, et al.
(author)
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Three-dimensional structure determination with an X-ray laser
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Other publication (other academic/artistic)abstract
- Three-dimensional structure determination of a non-crystalline virus has been achieved from a set of randomly oriented continuous diffraction patterns captured with an X-ray laser. Intense, ultra-short X-ray pulses intercepted a beam of single mimivirus particles, producing single particle X-ray diffraction patterns that are assembled into a three-dimensional amplitude distribution based on statistical consistency. Phases are directly retrieved from the assembled Fourier distribution to synthesize a three-dimensional image. The resulting electron density reveals a pseudo-icosahedral asymmetric virion structure with a compartmentalized interior, within which the DNA genome occupies only about a fifth of the volume enclosed by the capsid. Additional electron microscopy data indicate the genome has a chromatin-like fiber structure that has not previously been observed in a virus.
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| 6. |
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| 7. |
- Jansen, Iris E, et al.
(author)
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Genome-wide meta-analysis for Alzheimer's disease cerebrospinal fluid biomarkers.
- 2022
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In: Acta neuropathologica. - : Springer Science and Business Media LLC. - 1432-0533 .- 0001-6322. ; 144:5, s. 821-842
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Journal article (peer-reviewed)abstract
- Amyloid-beta 42 (Aβ42) and phosphorylated tau (pTau) levels in cerebrospinal fluid (CSF) reflect core features of the pathogenesis of Alzheimer's disease (AD) more directly than clinical diagnosis. Initiated by the European Alzheimer & Dementia Biobank (EADB), the largest collaborative effort on genetics underlying CSF biomarkers was established, including 31 cohorts with a total of 13,116 individuals (discovery n=8074; replication n=5042 individuals). Besides the APOE locus, novel associations with two other well-established AD risk loci were observed; CR1 was shown a locus for Aβ42 and BIN1 for pTau. GMNC and C16orf95 were further identified as loci for pTau, of which the latter is novel. Clustering methods exploring the influence of all known AD risk loci on the CSF protein levels, revealed 4 biological categories suggesting multiple Aβ42 and pTau related biological pathways involved in the etiology of AD. In functional follow-up analyses, GMNC and C16orf95 both associated with lateral ventricular volume, implying an overlap in genetic etiology for tau levels and brain ventricular volume.
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| 8. |
- Jansen, Willemijn J, et al.
(author)
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Prevalence Estimates of Amyloid Abnormality Across the Alzheimer Disease Clinical Spectrum.
- 2022
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In: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 79:3, s. 228-243
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Journal article (peer-reviewed)abstract
- One characteristic histopathological event in Alzheimer disease (AD) is cerebral amyloid aggregation, which can be detected by biomarkers in cerebrospinal fluid (CSF) and on positron emission tomography (PET) scans. Prevalence estimates of amyloid pathology are important for health care planning and clinical trial design.To estimate the prevalence of amyloid abnormality in persons with normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia and to examine the potential implications of cutoff methods, biomarker modality (CSF or PET), age, sex, APOE genotype, educational level, geographical region, and dementia severity for these estimates.This cross-sectional, individual-participant pooled study included participants from 85 Amyloid Biomarker Study cohorts. Data collection was performed from January 1, 2013, to December 31, 2020. Participants had normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia. Normal cognition and subjective cognitive decline were defined by normal scores on cognitive tests, with the presence of cognitive complaints defining subjective cognitive decline. Mild cognitive impairment and clinical AD dementia were diagnosed according to published criteria.Alzheimer disease biomarkers detected on PET or in CSF.Amyloid measurements were dichotomized as normal or abnormal using cohort-provided cutoffs for CSF or PET or by visual reading for PET. Adjusted data-driven cutoffs for abnormal amyloid were calculated using gaussian mixture modeling. Prevalence of amyloid abnormality was estimated according to age, sex, cognitive status, biomarker modality, APOE carrier status, educational level, geographical location, and dementia severity using generalized estimating equations.Among the 19097 participants (mean [SD] age, 69.1 [9.8] years; 10148 women [53.1%]) included, 10139 (53.1%) underwent an amyloid PET scan and 8958 (46.9%) had an amyloid CSF measurement. Using cohort-provided cutoffs, amyloid abnormality prevalences were similar to 2015 estimates for individuals without dementia and were similar across PET- and CSF-based estimates (24%; 95% CI, 21%-28%) in participants with normal cognition, 27% (95% CI, 21%-33%) in participants with subjective cognitive decline, and 51% (95% CI, 46%-56%) in participants with mild cognitive impairment, whereas for clinical AD dementia the estimates were higher for PET than CSF (87% vs 79%; mean difference, 8%; 95% CI, 0%-16%; P=.04). Gaussian mixture modeling-based cutoffs for amyloid measures on PET scans were similar to cohort-provided cutoffs and were not adjusted. Adjusted CSF cutoffs resulted in a 10% higher amyloid abnormality prevalence than PET-based estimates in persons with normal cognition (mean difference, 9%; 95% CI, 3%-15%; P=.004), subjective cognitive decline (9%; 95% CI, 3%-15%; P=.005), and mild cognitive impairment (10%; 95% CI, 3%-17%; P=.004), whereas the estimates were comparable in persons with clinical AD dementia (mean difference, 4%; 95% CI, -2% to 9%; P=.18).This study found that CSF-based estimates using adjusted data-driven cutoffs were up to 10% higher than PET-based estimates in people without dementia, whereas the results were similar among people with dementia. This finding suggests that preclinical and prodromal AD may be more prevalent than previously estimated, which has important implications for clinical trial recruitment strategies and health care planning policies.
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| 9. |
- Lee, Hyung-Seok, et al.
(author)
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Influence of the base contact on the electrical characteristics of SiC BJTs
- 2007
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In: 19th International Symposium on Power Semiconductor Devices and ICs, ISPSD'07. - 9781424410958 ; , s. 153-156
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Conference paper (peer-reviewed)abstract
- In this paper, we have investigated how the specific on-resistance and common emitter current gain of SiC BJTs depend on the base contact resistance. The on-state characteristics of SiC BJTs were investigated before and after base contact annealing at different temperatures. The common emitter current gain and specific on-resistance was improved by 23 % and 300 % compared to the values of before base contact annealing, respectively. Large area SiC BJTs (active area 0.0324 cm(2)), have been measured up to 34 A collector current in pulsed mode showing a gain of 35, and a specific on-resistance of 2 8.79 m Omega center dot cm(2)
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| 10. |
- Lutz, Josef, et al.
(author)
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The nn(+)-Junction as the Key to Improved Ruggedness and Soft Recovery of Power Diodes
- 2009
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In: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383 .- 1557-9646. ; 56:11, s. 2825-2832
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Journal article (peer-reviewed)abstract
- The effects during reverse recovery of pin power diodes are determined by free carriers and their interaction with the electric field. A density of free carriers higher than the background doping will easily occur in space-charge regions during reverse recovery of high-voltage silicon devices. As a result, a high electric-field strength combined with avalanche generation occurs at the p-n junction. However, if a second region with high electric-field strength arises at the nn(+)-junction, the situation can become critical. If the second electric-field peak can be suppressed, it is possible to make diodes that are very rugged and show a significantly improved soft-recovery behavior.
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