| 1. |
- Abbasi, Rasha, et al.
(författare)
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IceCube search for neutrinos from GRB 221009A
- 2023
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Ingår i: Proceedings of 38th International Cosmic Ray Conference (ICRC 2023). - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- GRB 221009A is the brightest Gamma Ray Burst (GRB) ever observed. The observed extremelyhigh flux of high and very-high-energy photons provide a unique opportunity to probe the predictedneutrino counterpart to the electromagnetic emission. We have used a variety of methods to searchfor neutrinos in coincidence with the GRB over several time windows during the precursor, promptand afterglow phases of the GRB. MeV scale neutrinos are studied using photo-multiplier ratescalers which are normally used to search for galactic core-collapse supernovae neutrinos. GeVneutrinos are searched starting with DeepCore triggers. These events don’t have directionallocalization, but instead can indicate an excess in the rate of events. 10 GeV - 1 TeV and >TeVneutrinos are searched using traditional neutrino point source methods which take into accountthe direction and time of events with DeepCore and the entire IceCube detector respectively. The>TeV results include both a fast-response analysis conducted by IceCube in real-time with timewindows of T0 − 1 to T0 + 2 hours and T0 ± 1 day around the time of GRB 221009A, as well asan offline analysis with 3 new time windows up to a time window of T0 − 1 to T0 + 14 days, thelongest time period we consider. The combination of observations by IceCube covers 9 ordersof magnitude in neutrino energy, from MeV to PeV, placing upper limits across the range forpredicted neutrino emission.
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| 2. |
- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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| 3. |
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| 4. |
- Bollati, Michela, et al.
(författare)
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Structure and functionality in flavivirus NS-proteins : perspectives for drug design
- 2010
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Ingår i: Antiviral Research. - : Elsevier BV. - 0166-3542 .- 1872-9096. ; 87:2, s. 125-148
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Forskningsöversikt (refereegranskat)abstract
- Flaviviridae are small enveloped viruses hosting a positive-sense single-stranded RNA genome. Besides yellow fever virus, a landmark case in the history of virology, members of the Flavivirus genus, such as West Nile virus and dengue virus, are increasingly gaining attention due to their re-emergence and incidence in different areas of the world. Additional environmental and demographic considerations suggest that novel or known flaviviruses will continue to emerge in the future. Nevertheless, up to few years ago flaviviruses were considered low interest candidates for drug design. At the start of the European Union VIZIER Project, in 2004, just two crystal structures of protein domains from the flaviviral replication machinery were known. Such pioneering studies, however, indicated the flaviviral replication complex as a promising target for the development of antiviral compounds. Here we review structural and functional aspects emerging from the characterization of two main components (NS3 and NS5 proteins) of the flavivirus replication complex. Most of the reviewed results were achieved within the European Union VIZIER Project, and cover topics that span from viral genomics to structural biology and inhibition mechanisms. The ultimate aim of the reported approaches is to shed light on the design and development of antiviral drug leads.
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| 5. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Vibrotactile Thresholds on the Mastoid and Forehead Position of Deaf Patients Using Radioear B71 and B81
- 2017
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Ingår i: Ear and Hearing. - 1538-4667 .- 0196-0202. ; 38:6, s. 714-723
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The main objective of this study was to measure the vibrotactile thresholds on the mastoid process and forehead positions using patients with bilateral deafness and to compare the results from the two bone conduction vibrators Radioear B71 and B81. Design: There is a possibility that the vibrotactile sensation on the skin makes it difficult to discriminate between sound and vibration. The risk is highest for patients who have bone conduction hearing thresholds in proximity to or worse than their vibrotactile thresholds. All measurements were performed similar to regular bone conduction threshold testing using an audiometer-driven bone conduction vibrator and pulsed warble tones, but the patients were instructed to respond only when feeling vibrations of the bone conduction vibrator instead of when hearing sound. Both the posterior forehead position and the mastoid process position on the temporal bone were tested for comparative reasons. In total, 16 patients participated in the study, 31% females and 69% males of age 29 to 77 years. All subjects were cochlear implant recipients, either uni-or bilaterally implanted. They were selected based on their audiogram data showing unmeasurable unaided hearing. Results: The force level at which the vibrotactile thresholds were reached, increased with frequency from 125 up to 500 Hz, but remained constant for higher frequencies up to 2 kHz. A statistically significant difference was found between the 2 devices at 125 Hz at both the mastoid process and forehead position, where the vibrotactile threshold seem to be more sensitive for B71, possibly due to contribution of distortion components. There was no statistically significant difference in vibrotactile thresholds between the mastoid process and forehead position in absolute values (force level in dB re 1 mu N), but in terms of hearing levels (dB HL) there was an average difference of 10 and 9 dB for B71 and B81, respectively. Conclusions: The results indicate that the vibrotactile thresholds can be confounded with bone conduction hearing thresholds measurements up to 500 Hz when using a standard audiometer and in particular when measuring on the forehead position.
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| 6. |
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| 7. |
- Hansson, Marie, 1979, et al.
(författare)
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Iodine content and distribution in extratumoral and tumor thyroid tissue analyzed with X-ray fluorescence and time-of-flight secondary ion mass spectrometry.
- 2008
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Ingår i: Thyroid : official journal of the American Thyroid Association. - : Mary Ann Liebert Inc. - 1557-9077. ; 18:11, s. 1215-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The thyroid's ability to enrich and store iodine has implications for thyroid cancer genesis, progression, and treatment. The study objective was to investigate thyroid iodine content (TIC) in tumoral and extratumoral tissue in patients with papillary thyroid cancer (PTC) as opposed to thyroid healthy controls using two different techniques: X-ray fluorescence (XRF) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). METHODS: Tissue samples from 10 patients with normal thyroids and 7 patients with PTC were collected. TIC was quantified with XRF, and the iodine stores were located on a histological level with TOF-SIMS. RESULTS: Mean TIC in controls was 0.6 mg/mL (range 0.3-1.2 mg/mL). For the cancer patients, the mean TIC was 0.8 mg/mL (range 0.2-2.3 mg/mL) in extratumoral thyroid tissue, but no iodine was detected in the tumors. TOF-SIMS investigation of the PTC patients showed significantly higher TIC in extratumoral tissue than in tumoral tissue. Iodine in the extratumoral tissue was predominantly located in the follicle lumen with a variation in concentration among follicles. CONCLUSIONS: XRF and TOF-SIMS are two complementary methods for obtaining insight into content and localization of iodine in the thyroid. XRF can be used in vitro or in vivo on a large number of samples or patients, respectively. TOF-SIMS on the other hand provides detailed images of the iodine location. The combined information from the two methods is of value for further studies on iodine metabolism in thyroid malignancy.
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| 8. |
- Hong, Mei, 1972-
(författare)
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Analysis of Some Methods for Identifying Dynamic Errors-in-variables Systems
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A system where errors or noises are present on both the inputs and the outputs is called an errors-in-variables (EIV) system. EIV systems appear in industrial and agricultural processes, medical sciences, economical systems, biotechnology, as well as in many other areas. Until now, a considerable number of methods for identifying dynamic errors-in-variables systems have been proposed. This thesis studies the statistic properties of different EIV methods and explores the relationships between some of the existing methods. An EIV approach, based on a bias-compensated least squares scheme, is considered in this thesis. Three promising estimators are in focus, namely, Zheng's bias-eliminated least squares (BELS) methods, Frisch scheme methods and extended compensated least squares (ECLS) methods. A simplified form of the BELS equation is first proposed. The new equation will simplify the computation and the theoretical analysis. Next, an important relationship between the BELS, Frisch and ECLS methods is found. The defining non-linear equations used by these three methods are equivalent, providing that the same extended model is used. This means that despite the use of different techniques to solve these equations, the three methods will have the same asymptotic estimation accuracy. Furthermore, the thesis studies the convergence properties of BELS. An alternative BELS algorithm is proposed, which has less of a divergence problem under low SNR situations as compared to the classic BELS methods. Another important problem which is investigated in the thesis is the asymptotic accuracy of the estimates. For the BELS method and a third-order cumulants based method, explicit expressions for the covariance matrices of the parameter estimates are derived. With such expressions available, one may obtain insight into how different user choices in the algorithms influence the accuracy. By using the expressions for the covariance matrices, comparisons of the estimation accuracies are made between three Frisch methods and between the time-domain maximum likelihood method and the sample maximum likelihood method. Finally, identification of errors-in-variables systems with periodic input signals is considered. How to utilize the periodic data and how to design instrumental variables in order to achieve the optimal estimation accuracy are analyzed as well.
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| 10. |
- Jansson, Anna M., et al.
(författare)
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Structure of the methyltransferase domain from the Modoc virus, a flavivirus with no known vector
- 2009
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Ingår i: Acta Crystallographica Section D. - 0907-4449 .- 1399-0047. ; 65, s. 796-803
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Tidskriftsartikel (refereegranskat)abstract
- The Modoc virus (MODV) is a flavivirus with no known vector (NKV). Evolutionary studies have shown that the viruses in the MODV group have evolved in association with mammals (bats, rodents) without transmission by an arthropod vector. MODV methyltransferase is the first enzyme from this evolutionary branch to be structurally characterized. The high-resolution structure of the methyltransferase domain of the MODV NS5 protein (MTase(MODV)) was determined. The protein structure was solved in the apo form and in complex with its cofactor S-adenosyl-l-methionine (SAM). Although it belongs to a separate evolutionary branch, MTase(MODV) shares structural characteristics with flaviviral MTases from the other branches. Its capping machinery is a relatively new target in flaviviral drug development and the observed structural conservation between the three flaviviral branches indicates that it may be possible to identify a drug that targets a range of flaviviruses. The structural conservation also supports the choice of MODV as a possible model for flavivirus studies.
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