| 1. |
- Bridel, Claire, et al.
(författare)
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Diagnostic Value of Cerebrospinal Fluid Neurofilament Light Protein in Neurology : A Systematic Review and Meta-analysis
- 2019
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 76:9, s. 1035-1048
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Forskningsöversikt (refereegranskat)abstract
- Importance Neurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date.Objectives To assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions.Data Sources PubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC.Study Selection Studies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex.Data Extraction and Synthesis Individual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept.Main Outcome and Measure The cNfL levels adjusted for age and sex across diagnoses.Results Data were collected for 10 059 individuals (mean [SD] age, 59.7 [18.8] years; 54.1% female). Thirty-five diagnoses were identified, including inflammatory diseases of the central nervous system (n = 2795), dementias and predementia stages (n = 4284), parkinsonian disorders (n = 984), and HC (n = 1332). The cNfL was elevated compared with HC in a majority of neurological conditions studied. Highest levels were observed in cognitively impaired HIV-positive individuals (iHIV), amyotrophic lateral sclerosis, frontotemporal dementia (FTD), and Huntington disease. In 33.3% of diagnoses, including HC, multiple sclerosis, Alzheimer disease (AD), and Parkinson disease (PD), cNfL was higher in men than women. The cNfL increased with age in HC and a majority of neurological conditions, although the association was strongest in HC. The cNfL overlapped in most clinically similar diagnoses except for FTD and iHIV, which segregated from other dementias, and PD, which segregated from atypical parkinsonian syndromes.Conclusions and Relevance These data support the use of cNfL as a biomarker of neuroaxonal damage and indicate that age-specific and sex-specific (and in some cases disease-specific) reference values may be needed. The cNfL has potential to assist the differentiation of FTD from AD and PD from atypical parkinsonian syndromes.
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| 2. |
- Jakobsson, Fredrik L.E. 1974-, et al.
(författare)
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On the switching mechanism in Rose Bengal-based memory devices
- 2007
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Ingår i: Organic electronics. - : Elsevier BV. - 1566-1199. ; 8:5, s. 559 -565
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Tidskriftsartikel (refereegranskat)abstract
- Impedance switching has been observed in many organic devices, but the mechanism is still a matter of debate. Reliable switch devices consisting of an organic layer of Rose Bengal derivatives sandwiched in between indium tin oxide and aluminum electrodes were fabricated. Modifying the chemical nature of the organic layers and visualizing the temperature distribution in the organic memory rule out several mechanisms. It is shown that the memory effect originates from filamentary switching.
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| 3. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(författare)
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Prediction of the current versus voltage behavior of devices based on organic semiconductor host-guest systems
- 2009
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Ingår i: Organic electronics. - : Elsevier BV. - 1566-1199 .- 1878-5530. ; 10:1, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- Organic semiconductor blends are commonly used in organic based (opto-)electronic devices. They are composed of two types of (macro-) molecules, referredto as the guest and host. To achieve optimum device operation, the chemicalnature, electronic structure, molecular order and the relative concentration of theguests and host are crucial. Here, we present simulation results of the currentdensity versus the voltage (J-V) behavior of a two-terminal device based on avariable-range hopping model in which the electronic states of the guest and hostare represented by two Gaussian distributions. The J-V behavior is investigatedfor various energetic mismatches between guest and host states, widths of thedistribution as well as the guest concentration. Finally, a simple tool enablingeasy prediction of the J-V behavior of organic host-guest diodes is derived.
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| 4. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(författare)
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Towards addressable organic impedance switch devices
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87:6
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Tidskriftsartikel (refereegranskat)abstract
- The addressability of organic impedance switch devices as the memory elements of cross-point matrices is improved by introducing nonlinear behavior in their current-voltage characteristics. This is realized by adding a semiconducting layer of copper (II) phthalocyanine (CuPc) on top of the switch layer of Rose Bengal (RB) sodium salt. Leakage currents from unaddressed cells in a matrix are reduced by a factor of 17; thus improving the signal-to-background ratio, reducing driver currents and limiting the potential drop along the addressing lines. The matrix size of RB switch devices, using organic conductors, is predicted to be increased by 32 times when using the additional CuPc layer.
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| 5. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(författare)
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Towards all-plastic flexible light emitting diodes
- 2006
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 433:1-3, s. 110-114
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Tidskriftsartikel (refereegranskat)abstract
- All-plastic light emitting diodes require the design and fabrication of low work function plastic electrodes. Here, we show that the work function of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT-PSS) can be decreased from 4.8 eV to 3.9 eV by surface reaction with the strong electron-donor tetrakis(dimethylamino)ethylene (TDAE). The surface modification was characterized by photoelectron spectroscopy and optical spectroscopy. The low work function plastic electrode was used in a first prototype for all-plastic light emitting diodes.
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| 6. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(författare)
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Tuning the energy levels of photochromic diarylethene compounds for optoelectronic switch devices
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Photochromic diarylethene molecules (PC) is investigated for use in opticalwrite/electrical read memory applications. The frontier energy levels and dipolemoment is calculated using density functional theory. Good agreement is foundbetween calculated electronic structure and measured ultraviolet photoelectronspectra. The changes in frontier energy levels and dipole moment are scrutinizedupon two different approaches for chemical modification: (i) adding substituentsto the ethylene bridge; or (ii) changing the chemical nature of the aryl rings.Through the chemical modification the frontier energy levels can be tuned bymore than 2 eV. The calculated molecular properties are used in charge transportmodels to predict the behavior of devices based on these molecules. By using thePC in combination with an organic semiconductor (in bilayer or blend) goodswitching behavior can be achieved in a device. The switch effect is predicted tobe mainly due to switch in frontier energy levels rather than switch of dipolemoment. This is concluded since the dipole moment is either too small (< 5 D) orthe switch effect to small (less than a factor of two).
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