| 1. |
- Carlsson, Björn, 1958, et al.
(författare)
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Obese (ob) gene defects are rare in human obesity
- 1997
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Ingår i: Obesity Research. - 1071-7323 .- 1550-8528. ; 5:1, s. 30-5
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Tidskriftsartikel (refereegranskat)abstract
- Our knowledge of the role of the recently cloned ob-protein (leptin) in the regulation of body fat stores is largely derived from experiments performed in mice. Different mouse models exhibit abnormalities in ob-gene expression, with extreme overexpression in mice which lack bioactive ob-protein, have nonfunctional ob-receptors or hypothalamic lesions, and undetectable expression in mice with suggested defects in regulatory elements. The aim of this study is to examine if defects, corresponding to those in mice, exist in human obesity. Adipose tissue was obtained from 94 adult obese subjects and from six children who had developed obesity after surgery in the hypothalamic region. Total RNA was isolated and ob-gene expression was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Northern blot. The coding region of the ob-gene was sequenced in both directions in the 94 obese adults. No mutations were detected in the coding region of the ob-gene and ob-gene expression was detectable in all subjects and none of the subjects had an extreme overexpression. There was no systematic increase in ob-expression in obese children with hypothalamic disease compared to their healthy brothers and sisters. These results show that severe abnormalities involving the ob-gene, analogous to those described in mouse models, are rare in human obesity. We therefore conclude that the cloning and subsequent analysis of the ob-gene has not provided information that can, by itself, explain the genetic component in the development of human obesity.
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| 2. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Structural study and proton conductivity in Yb-doped BaZrO3
- 2007
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Ingår i: Solid State Ionics. - 0167-2738. ; 178:(7-10), s. 515-520
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Tidskriftsartikel (refereegranskat)abstract
- Traditional solid state sintering has been used to prepare the perovskite BaZr0.9Yb0.1O3-delta. Analysis of X-ray powder diffraction data shows that an increase of the unit cell parameter, a, was observed compared to undoped BaZrO3. Rietveld analysis of room temperature neutron powder diffraction data confirmed cubic symmetry (space group Pm-3m). Dynamic thermogravimetric analysis (TGA) indicates that the hydration process occurs below 200 degrees C. The strong O-H stretch band, 2500-3500 cm(-1), in the infrared absorbance spectrum clearly manifests the presence of protons in the hydrated material. Proton conductivity was investigated on hydrated and as-prepared samples under dry and wet atmospheres, respectively. Keywords: X-ray diffraction; neutron diffraction; Rietveld refinement; proton conductor; perovskite
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| 3. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Synthesis and structural characterization of perovskite type proton conducting BaZr1-xInxO3-delta (0.0 <= x <= 0.75)
- 2006
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738 .- 1872-7689. ; 177:17-18, s. 1395-1403
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Tidskriftsartikel (refereegranskat)abstract
- Solid state sintering has been used to prepare the cubic perovskite structured compounds BaZr1-xInxO3-delta (0.0 <= x <= 0.75). Analysis of X-ray powder diffraction (XRPD) data reveals that the unit cell parameter, a, increases linearly with an increased Indium concentration. XRPD data was also used to demonstrate the completion of sample hydration, which was reached when the materials showed a set of single-phase Bragg-peaks. Dynamic thermogravimetric analysis (TGA) data showed that approx. 89% of the total number of available oxygen vacancies can be filled in BaZr1-xInxO3-delta for x=0.50, and that the maximum water uptake occurs below 300 degrees C. Rietveld analysis of the room temperature neutron powder diffraction (NPD) data confirmed the average cubic symmetry (space group Pm-3m), and an expansion of the unit cell parameter after the hydration reaction. The strong O-H stretch band, 2500-3500 cm(-1), in the infrared absorbance spectrum clearly manifests the presence of protons in the hydrated material. Proton conductivity of hydrated BaZr1-xInxO3-delta, x=0.75 was investigated during heating and cooling cycles under dry argon atmosphere. The total conductivity during the heating cycle was nearly two orders of magnitude greater than that of cooling cycle at 300 degrees C, whilst these values were similar at higher temperatures i.e. T > 600 degrees C.
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| 4. |
- Eismark, Jan, 1962, et al.
(författare)
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Role of turbulence for mixing and soot oxidation for an equivalent diesel gas jet during wall interaction studied with LES.
- 2012
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Ingår i: Proceeding of THIESEL 2012.
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Konferensbidrag (refereegranskat)abstract
- Using Large Eddy Simulations (LES), turbulent properties were studied of an equivalent diesel fuel gas jet having a vapour phase penetration equal as for a diesel spray. Half side of the jet was forced to sharply change direction by impinging upon a curved wall. The other side of the jet developed freely acting as a reference case. It was shown how turbulent structures of various scales develop along the jet and after wall impingement. The turbulent eddies contribute strongly to air entrainment into the jet resulting in an increasing rate of dilution of the jet core downstream of the fuel nozzle. Calculations of the instantaneous fuel concentration were used to study the total surface area and the kinetic energy of the wrinkled stoichiometric zones. Both the resolved kinetic energy and the sub-grid scale turbulent kinetic energy of the stoichiometric zones were found to increase on the wall side. Statistics of turbulent quantities were computed across interesting sections showing relations between velocity gradients, turbulent velocity field, turbulence production and dissipation. The findings were used for a reasoning about the role of turbulence for soot oxidation in a real diesel flame. Previous observations in a high temperature, high pressure combustion chamber experiment that turbulent eddies sweep fresh gas into the free jet core were confirmed by the simulations. As observed in the experiments, the LES results indicate that also non-fresh gases, especially on the wall side, may be swept into the jet side. As a result, soot oxidation rate can either increase if oxidant radicals are supplied by the turbulent flow or decrease if the in-rushing gases mainly consist of inert combustion products.
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| 5. |
- Gabrielsson, Britt, 1957, et al.
(författare)
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Molecular characterization of a local sulfonylurea system in human adipose tissue.
- 2004
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Ingår i: Molecular and cellular biochemistry. - 0300-8177 .- 1573-4919. ; 258:1-2, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- ATP-sensitive potassium (KATP) channels are present in many cell types and link cellular metabolism to the membrane potential. These channels are heterooctamers composed of two subunits. The sulfonylurea receptor (SUR) subunits are targets for drugs that are inhibitors or openers of the KATP channels, while the inwardly rectifying K+ (Kir) subunits form the ion channel. Two different SUR genes (SUR1 and SUR2) and two different Kir6.x genes (Kir6.1 and Kir6.2) have been identified. In addition, isoforms of SUR2, SUR2A and SUR2B, have been described. We have previously performed expression profiling on pooled human adipose tissue and found high expression of SUR2. Others have reported expression of SUR1 in human adipocytes. The aim of this study was to characterize the expression of the sulfonylurea receptor complex components in human adipose tissue. RT-PCR analysis, verified by restriction enzyme digestions and DNA sequencing, showed that SUR2B, Kir6.1 and alpha-endosulfine, but not SUR1, SUR2A or Kir6.2, are expressed in human adipose tissue. Real-time RT-PCR showed that SUR2B was expressed at higher levels in subcutaneous compared with omental adipose tissue in paired biopsies obtained from seven obese men (p < 0.05). Analysis of tissue distribution showed that SUR2B expression in adipose tissue was lower than that in muscle, similar to that in heart and liver, while the expression in pancreas was lower. The effect of caloric restriction was tested in obese men (n = 10) treated with very low calorie diet for 16 weeks, followed by a gradual reintroduction of ordinary food for 2 weeks. Biopsies were taken at week 0, 8 and 18. There was no consistent effect of weight reduction on SUR2B or Kir6.1 expression. We conclude that the necessary components for a local sulfonylurea system are expressed in human adipose tissue and that the sulfonylurea receptor complex in this tissue is composed of SUR2B and Kir6.1. The expression of SUR2B was higher in subcutaneous compared with omental adipose tissue and was not affected by weight loss.
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| 6. |
- Johansson, Birgitta, 1957, et al.
(författare)
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Mindfulness-Based Stress Reduction (MBSR) Delivered Live on the Internet to Individuals Suffering from Mental Fatigue After an Acquired Brain Injury
- 2015
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Ingår i: Mindfulness. - : Springer Science and Business Media LLC. - 1868-8527 .- 1868-8535. ; 6:6, s. 1356-1365
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Tidskriftsartikel (refereegranskat)abstract
- An acquired brain injury often leads to long-lasting mental fatigue, which can have a considerable effect on work and social interactions. Fortunately, the Mindfulness-Based Stress Reduction (MBSR) program has been found to alleviate mental fatigue. The purpose of this feasibility study was to evaluate the success of an interactive MBSR program delivered live online to individuals who have experienced a traumatic brain injury or stroke. We included the following three groups in our study: an Internet group, a face-to-face MBSR group, and an active control group who took weekly walks in natural environments. Thirty-four participants completed the study, and all were suffering from long-lasting mental fatigue after either a traumatic brain injury (16 participants) or a stroke (18 participants). However, seven did not accept to attend an Internet MBSR, and Internet was the only choice for others. We found that, according to the Mental Fatigue Scale (MFS), the program leads to significantly reduced mental fatigue in the Internet group compared with the face-to-face and the control group. Individuals in the MBSR groups also exhibited an improved ability to process two temporally close targets (attentional blink task), while this was not detected in the control group. In conclusion, we believe that it is possible for individuals suffering from mental fatigue after an acquired brain injury to obtain positive results through enrollment in a live, interactive, online MBSR program. This is promising, as the Internet is accessible to many individuals, irrespective of where they live. Further randomized control studies comparing are warranted.
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| 7. |
- Rydén, Anna, 1957, et al.
(författare)
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Obesity-related coping and distress and relationship to treatment preference.
- 2001
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Ingår i: The British journal of clinical psychology / the British Psychological Society. - 0144-6657. ; 40:2, s. 177-88
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The primary purpose was to define obesity-related strategies for coping with psychological problems connected with obesity. We also wanted to identify obesity-related distress and explore the effect of coping on distress. Thirdly, we wanted to investigate differences in coping and distress related to choice of surgery or conventional treatment. DESIGN: Cross-sectional data from patients in the Swedish Obese Subjects (SOS) intervention study. METHODS: An obesity-related questionnaire concerning coping and distress was created and evaluated in 2510 patients from the SOS study, using multitrait, exploratory and confirmatory factor analysis procedures. RESULTS: Three coping factors were defined. Social Trust and Fighting Spirit were problem-focused, whereas Wishful Thinking was emotion-focused. Surgical candidates displayed lower levels of problem-focused and higher levels of emotion-focused coping. We also identified two distress factors: Intrusion and Helplessness. Wishful Thinking was positively related to distress, and Social Trust and Fighting Spirit were inversely related, thus explaining the higher levels of distress reported by the surgical candidates. CONCLUSIONS: In our sample, emotion-focused coping proved maladaptive and was associated with increased distress. Problem-focused coping, however, was adaptive and associated with reduced distress. These findings partly explain psychological morbidity and should be taken into consideration in the treatment of obese people.
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| 8. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Crystal structure and proton conductivity of BaZr0.9Sc0
- 2008
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Ingår i: Journal of the American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 91:9, s. 3039-3044
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Tidskriftsartikel (refereegranskat)abstract
- Solid-state sintering has been used to prepare the perovskite BaZr0.9Sc0.1O3-delta. Analysis of X-ray powder diffraction data shows that an increase of the unit cell parameter, a, was observed after deuteration. Rietveld analysis of room-temperature neutron powder diffraction data confirmed cubic symmetry (space group Pm-3m). Dynamic thermogravimetric analysis indicates that the hydration process occurs below 335 degrees C and approximately 58% of the theoretical number of protonic defects can be filled. The presence of protons/deutrons is seen from the strong O-H/O-D stretch band in the infrared spectrum of the hydrated/deuterated samples. The proton conductivity of a prehydrated sample was investigated under dry and wet Ar atmospheres
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| 9. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Location of deuteron sites in the proton conducting perovskite BaZr0.50In0.50O3-y
- 2008
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 450:1-2, s. 103-110
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution neutron powder diffraction data have been collected on deuterated and dried samples of the perovskite BaZr0.5In0.5O2.75 at 5 K and room temperature, respectively. Inspection of Fourier nuclear density maps for the deuterated phase have allowed the deuteron position to be refined on a 12h (1/2, y, 0) crystallographic site, with y = 0.217(4) yielding a chemically reasonable O-D distance of 0.92(2) angstrom. Evidence for anisotropy of the deuteron position is also found consistent with a 24k crystallographic site (0.56, 0.21, 0) indicative of displacements of the ion towards neighbouring oxygen ions. The presence of static oxygen disorder in both the dried and deuterated samples is apparent from the structural analyses. Raman spectra confirm short range deviations from cubic symmetry for both dried and hydrated samples.
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| 10. |
- Ahmed, Istaq, 1972, et al.
(författare)
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Proton conduction in Perovskite Oxide BaZr0.5Yb0.5O3-δ Prepared by Wet Chemical Route
- 2008
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 155:11, s. 97-102
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Tidskriftsartikel (refereegranskat)abstract
- A wet chemical route has been used to synthesize the oxygen deficient perovskite Ba Zr0.5 Yb0.5 O3-δ. Analysis of X-ray powder diffraction data showed that both dried and hydrated samples adopt cubic crystal structures of space group Pm 3- m. Dynamic thermogravimetric analysis showed a significant mass loss for the hydrated sample compared to the dried sample, indicating that ∼28% of the oxygen vacancies are filled by protonic defects. The strong O-H stretch band, 2500-3500 cm-1, in the IR absorbance spectrum also clearly manifests the presence of significant levels of protons in the hydrated material. Proton conductivity was investigated on prehydrated (under dry Ar) and as-prepared (under wet Ar) samples. The heating cycle of the prehydrated sample showed higher proton conductivity compared to the cooling cycle, especially in the intermediate temperature range (150-550°C). Finally, comparison with data for Ba Zr0.9 Yb0.1 O3-δ revealed that the more heavily doped sample showed higher proton conductivity compared to the more lightly doped sample. © 2008 The Electrochemical Society.
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