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- Stella, Roberto, et al.
(författare)
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Relative Quantification of Membrane Proteins in Wild-Type and Prion Protein (PrP)-Knockout Cerebellar Granule Neurons
- 2012
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 11:2, s. 523-536
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Tidskriftsartikel (refereegranskat)abstract
- Approximately 25% of eukaryotic proteins possessing homology to at least two trans membrane domains are predicted to be embedded in biological membranes. Nevertheless, this group of proteins is not usually well represented in proteome-wide experiments due to their refractory nature. Here we present a quantitative mass spectrometry-based comparison of membrane protein expression in cerebellar granule neurons grown in primary culture that were isolated from wild-type mice and mice lacking the cellular prion protein. This protein is a cell-surface glycoprotein that is mainly expressed in the central nervous system and is involved in several neurodegenerative disorders, though its physiological role is unclear. We used a low specificity enzyme a-chymotrypsin to digest membrane proteins preparations that had been separated by SDS-PAGE. The resulting peptides were labeled with tandem mass tags and analyzed by MS. The differentially expressed proteins identified using this approach were further analyzed by multiple reaction monitoring to confirm the expression level changes.
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- af Klinteberg, Britt, et al.
(författare)
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Smoking habits – Associations with personality/behavior, platelet monoamine oxidase activity and plasma thyroid hormone levels
- 2017
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Ingår i: Personality and Individual Differences. - : Elsevier. - 0191-8869 .- 1873-3549. ; 118, s. 71-76
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Tidskriftsartikel (refereegranskat)abstract
- The objective was to outline results from our scientific studies on the associations among childhood behavior, adult personality, and biochemical factors in smoking habits. The studies consisted of: (1) follow-up of young criminals and controls, subdivided into risk for antisocial behavior groups, based on childhood rating levels of a projective test; and adult smoking habit groups; and (2) a large group of young adults examined on the same inventories. Personality in terms of KSP and EPQ-I scale scores, controlled for intelligence, indicated that the high and very high risk groups displayed significantly higher self-rated impulsiveness, anxiety, and nonconformity, as compared to the low risk group. Further, the very high risk group subjects, found to be overrepresented among subjects with heavy smoking habits, displayed lower mean platelet MAO-B activity and higher thyroid hormone levels than the low risk group. Thus, the higher the childhood risk for antisocial behavior, the clearer the adult personality pattern making subjects more disposed for smoking appeared; and the higher smoking habits, the stronger the relationships with biochemical measures. Results are discussed in terms of possible underlying mechanisms influencing personality and smoking habits.
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- Bendz, Maria, et al.
(författare)
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Quantification of Membrane Proteins Using Nonspecific Protease Digestions
- 2009
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 8:12, s. 5666-5673
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Tidskriftsartikel (refereegranskat)abstract
- We present a mass spectrometry-based method for the identification and quantification of membrane proteins using the low-specificity protease Proteinase K, at very high pH, to digest proteins isolated by a modified SDS-PAGE protocol. The resulting peptides are modified with a fragmentation-directing isotope labeled tag. We apply the method to quantify differences in membrane protein expression of Bacillus subtilis grown in the presence or absence of glucose.
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7. |
- Bentz, Maria, et al.
(författare)
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Membrane protein identification: N-terminal labeling of nontryptic membrane protein peptides facilitates database searching
- 2008
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 7:2, s. 659-665
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Tidskriftsartikel (refereegranskat)abstract
- Membrane proteins are fairly refractory to digestion especially by trypsin, and less specific proteases, such as elastase and pepsin, are much more effective. However, database searching using nontryptic peptides is much less effective because of the lack of charge localization at the N and C termini and the absence of sequence specificity. We describe a method for N-terminal-specific labeling of peptides from nontryptic digestions of membrane proteins, which facilitates Mascot database searching and can be used for relative quantitation. The conditions for digestion have been optimized to obtain peptides of a suitable length for mass spectrometry (MS) fragmentation. We show the effectiveness of the method using a plasma membrane preparation from a leukemia cell line and demonstrate a large increase in the number of membrane proteins, with small extra-membranar domains being identified in comparison to previous published methods.
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8. |
- Blomberg, Staffan, et al.
(författare)
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Barn och socialt arbete : Socialhögskolans årsbok 2019
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Årsboken ger en inblick i delar av den forskning kring socialt arbete med barn som sker vid Socialhögskolan. Den ger också en kort introduktion till verksamheten vid Socialhögskolan.
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- Börjesson, Maria, 1974-, et al.
(författare)
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The value of time of car drivers choosing route: evidence from the Stockholm congestion charging trial
- 2007
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Ingår i: Proceedings of the European Transport Conference. - Leiden, Netherlands. ; , s. 14-
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Konferensbidrag (refereegranskat)abstract
- In applied travel demand forecasting (including network modeling), congestion charges are generally assumed to affect travelers in the same way as fuel costs and other travel costs do. However, there are several reasons to believe that congestion charges affect drivers differently than for example fuel costs: for exampel, it is more “visible”, since you (as a rule) pay each time you pass a cordon (or equivalent), and it is often connected with a certain amount of hassle to actually pay the charge (calling a customer service, for example). Moreover, the way car drivers actually weigh travel time versus monetary cost when they choose route is largely unknown, since time and monetary cost are in general so correlated (as opposed to values of time in mode choice etc.). Data from the Stockholm congestion charging trial allow us to explore this question in detail. Car drivers traveling between the northern part of the county and the southern part could choose either to go through the cordon (paying two charges – 20-40 SEK depending on the time of day) or use the Essinge bypass, which was free of charge – a considerable detour for some trip relations. We use a large panel travel survey conducted before and during the charging trial to estimate the charging cost sensitivity compared to fuel cost sensitivity, and also estimate the actual value of time car drivers reveal when choosing route. Note that due to e.g. selection bias or travelers’ imperfect information about costs, this value of tme may differ from the average value of time for all travelers and also from the average value time for car drivers. The results is very applicable, in that it is easily incorporated into widely used traffic models (network equilibrium models or equivalent), allowing us to make more precise forecasts of the effects of congestion charges. It should also allow us to make more precise route choice modeling in other cases where routes have clearly different monetary costs.
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- Cappadona, Salvatore, et al.
(författare)
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Wavelet-based method for noise characterization and rejection in high-performance liquid chromatography coupled to mass spectrometry
- 2008
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 80:13, s. 4960-4968
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Tidskriftsartikel (refereegranskat)abstract
- We present a new method for rejecting noise from HPLC-MS data sets. The algorithm reveals peptides at low concentrations by minimizing both the chemical and the random noise. The goal is reached through a systematic approach to characterize and remove the background. The data are represented as two-dimensional maps, in order to optimally exploit the complementary dimensions of separation of the peptides offered by the LC-MS technique. The virtual chromatograms, reconstructed from the spectrographic data, have proved to be more suitable to characterize the noise than the raw mass spectra. By means of wavelet analysis, it was possible to access both the chemical and the random noise, at different scales of the decomposition. The novel approach has proved to efficiently distinguish signal from noise and to selectively reject the background while preserving low-abundance peptides.
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