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1.
J Microsc ; 281(1): 76-86, 2021 01.
Article in English | MEDLINE | ID: mdl-33439497

ABSTRACT

Combined focused ion beam and scanning electron microscope (FIB-SEM) tomography is a well-established technique for high resolution imaging and reconstruction of the microstructure of a wide range of materials. Segmentation of FIB-SEM data is complicated due to a number of factors; the most prominent is that for porous materials, the scanning electron microscope image slices contain information not only from the planar cross-section of the material but also from underlying, exposed subsurface pores. In this work, we develop a segmentation method for FIB-SEM data from ethyl cellulose porous films made from ethyl cellulose and hydroxypropyl cellulose (EC/HPC) polymer blends. These materials are used for coating pharmaceutical oral dosage forms (tablets or pellets) to control drug release. We study three samples of ethyl cellulose and hydroxypropyl cellulose with different volume fractions where the hydroxypropyl cellulose phase has been leached out, resulting in a porous material. The data are segmented using scale-space features and a random forest classifier. We demonstrate good agreement with manual segmentations. The method enables quantitative characterization and subsequent optimization of material structure for controlled release applications. Although the methodology is demonstrated on porous polymer films, it is applicable to other soft porous materials imaged by FIB-SEM. We make the data and software used publicly available to facilitate further development of FIB-SEM segmentation methods. LAY DESCRIPTION: For imaging of very fine structures in materials, the resolution limits of, e.g. X-ray computed tomography quickly become a bottleneck. Scanning electron microscopy (SEM) provides a way out, but it is essentially a two-dimensional imaging technique. One manner in which to extend it to three dimensions is to use a focused ion beam (FIB) combined with a scanning electron microscopy and acquire tomography data. In FIB-SEM tomography, ions are used to perform serial sectioning and the electron beam is used to image the cross section surface. This is a well-established method for a wide range of materials. However, image analysis of FIB-SEM data is complicated for a variety of reasons, in particular for porous media. In this work, we analyse FIB-SEM data from ethyl cellulose porous films made from ethyl cellulose and hydroxypropyl cellulose (EC/HPC) polymer blends. These films are used as coatings for controlled drug release. The aim is to perform image segmentation, i.e. to identify which parts of the image data constitute the pores and the solid, respectively. Manual segmentation, i.e. when a trained operator manually identifies areas constituting pores and solid, is too time-consuming to do in full for our very large data sets. However, by performing manual segmentation on a set of small, random regions of the data, we can train a machine learning algorithm to perform automatic segmentation on the entire data sets. The method yields good agreement with the manual segmentations and yields porosities of the entire data sets in very good agreement with expected values. The method facilitates understanding and quantitative characterization of the geometrical structure of the materials, and ultimately understanding of how to tailor the drug release.

2.
Int J Pharm ; 587: 119622, 2020 Sep 25.
Article in English | MEDLINE | ID: mdl-32663584

ABSTRACT

A porous network acts as transport paths for drugs through films for controlled drug release. The interconnectivity of the network strongly influences the transport properties. It is therefore important to quantify the interconnectivity and correlate it to transport properties for control and design of new films. This work presents a novel method for 3D visualisation and analysis of interconnectivity. High spatial resolution 3D data on porous polymer films for controlled drug release has been acquired using a focused ion beam (FIB) combined with a scanning electron microscope (SEM). The data analysis method enables visualisation of pore paths starting at a chosen inlet pore, dividing them into groups by length, enabling a more detailed quantification and visualisation. The method also enables identification of central features of the porous network by quantification of channels where pore paths coincide. The method was applied to FIB-SEM data of three leached ethyl cellulose (EC)/hydroxypropyl cellulose (HPC) films with different weight percentages. The results from the analysis were consistent with the experimentally measured release properties of the films. The interconnectivity and porosity increase with increasing amount of HPC. The bottleneck effect was strong in the leached film with lowest porosity.


Subject(s)
Polymers , Drug Liberation , Microscopy, Electron, Scanning , Porosity
3.
Psychiatry Res Neuroimaging ; 300: 111079, 2020 06 30.
Article in English | MEDLINE | ID: mdl-32283474

ABSTRACT

Heart rate variability (HRV), a measurement of autonomic nervous system (ANS) activity, has been found reduced in schizophrenia. The anterior cingulate cortex (ACC), which is important in regulating the ANS, is structurally and functionally affected in schizophrenia. We investigate the relationship between HRV and functional and structural connectivity of the ACC in patients with schizophrenia and healthy controls. Ten patients with a diagnosis of schizophrenia and ten healthy controls were recruited. Heart rate was monitored in a naturalistic out-of-clinic setting. Magnetic resonance imaging (MRI) was performed, including resting-state functional MRI and diffusion tensor imaging. Patients with schizophrenia had significantly lower HRV compared to controls. A positive correlation between ACC connectivity with the bilateral cerebellum and HRV was found in the patients. HRV was also positively correlated with amplitude of low frequency fluctuations (ALFF) in the cerebellum, and with axial diffusivity in the middle cerebellar peduncle, in the patients. There was a significant negative relationship between antipsychotic medication dosage, HRV and all neuroimaging measures related to HRV. We conclude that ACC connectivity seems to be affected in schizophrenia, both structurally and functionally, and that the ACC-cerebellum connectivity, as well as cerebellar function, is associated with ANS regulation in patients with schizophrenia.


Subject(s)
Autonomic Nervous System/physiopathology , Heart Rate/physiology , Nerve Net/physiopathology , Schizophrenia/physiopathology , Adult , Antipsychotic Agents/therapeutic use , Autonomic Nervous System/diagnostic imaging , Case-Control Studies , Cerebellum/diagnostic imaging , Cerebellum/physiopathology , Diffusion Tensor Imaging , Female , Gyrus Cinguli/diagnostic imaging , Gyrus Cinguli/physiopathology , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Nerve Net/diagnostic imaging , Schizophrenia/diagnostic imaging , Schizophrenia/drug therapy
4.
Osteoarthritis Cartilage ; 27(3): 476-483, 2019 03.
Article in English | MEDLINE | ID: mdl-30552967

ABSTRACT

OBJECTIVE: To investigate the relationship between meniscus magnetic resonance (MR) relaxation parameters and meniscus degradation through quantitative imaging of ex vivo posterior horns of menisci from subjects with and without knee osteoarthritis (OA). DESIGN: We sampled medial and lateral menisci from ten medial compartment knee OA patients (mean age 63 years) undergoing total knee replacement and from ten deceased donors (references, mean age 51 years). MR relaxation parameters T2*, T2 and T1 of the posterior horn were measured at a 9.4 T scanner. Comparisons were made between OA patients and references (with adjustment for age) as well as between medial and lateral menisci from the same knees. RESULTS: Mean values (standard deviation) of mean T2* were 13 (3.8), 6.9 (2.3), 7.2 (1.9) and 7.2 (1.7) ms for the medial and lateral patient menisci and the medial and lateral reference menisci, respectively. Corresponding values were 17 (3.7), 9.0 (2.2), 12 (4) and 9.0 (1.3) ms for T2 and 1810 (150), 1630 (30), 1580 (90) and 1560 (50) ms for T1. All three relaxation times were significantly longer in medial OA menisci compared to the other groups. Among medial reference menisci, relaxation times (mainly T1) tended to increase with age. CONCLUSIONS: MR relaxation times T2*, T2 and T1 in the posterior horn are longer in the medial menisci of patients with end-stage medial compartment knee OA compared to the corresponding lateral menisci and to reference menisci. The meniscus seems to undergo intrasubstance alterations related to both OA and ageing.


Subject(s)
Magnetic Resonance Imaging/methods , Meniscus/diagnostic imaging , Aged , Case-Control Studies , Female , Humans , Knee Joint/diagnostic imaging , Male , Middle Aged , Osteoarthritis, Knee/diagnostic imaging
6.
J Psychosom Res ; 97: 30-37, 2017 06.
Article in English | MEDLINE | ID: mdl-28606496

ABSTRACT

BACKGROUND: Emotional distress (depression and anxiety) has been known to affect mortality after a myocardial infarction (MI). One possible mechanism is through medication non-adherence. Few studies have investigated the link between statin adherence and emotional distress, and results are not consistent. We aimed to explore whether emotional distress affects adherence among first-time MI patients younger than 75years old receiving a prescription for the first time. METHODS: We identified first-MI individuals younger than 75years from the SWEDEHEART national quality registers discharged with a statin prescription. The main exposure was the anxiety/depression portion of the EQ-5D from Interview 1 (6-10weeks post-MI) and Interview 2 (12-14months post-MI). We calculated adherence from the Swedish Prescribed Drugs Register during three observation periods (OP): [1] Interview 1 to Interview 2, [2] one year post Interview 2, and [3] two years post Interview 1. RESULTS: Emotional distress at Interview 1 was not associated with statin adherence for OP1 (RR: 0.99, 95% CI: 0.98, 1.01). Emotional distress at Interview 2 was associated with lower adherence one year later (RR: 0.95, 95% CI: 0.93, 0.98). Emotional distress at Interview 1 was associated with a small decrease in adherence in the complete OP for adherence (RR: 0.98, 95% CI: 0.96, 0.99). CONCLUSION: Emotional distress was marginally, but independently, associated with lower adherence to statin two years after the MI. Our study suggests that emotional distress may be an important factor for long-term statin adherence, and, thus, may play a clinically important role in long-term outcome.


Subject(s)
Anxiety Disorders/psychology , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Medication Adherence/psychology , Myocardial Infarction/psychology , Stress, Psychological/chemically induced , Female , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Male , Middle Aged , Stress, Psychological/psychology , Sweden
7.
Micron ; 100: 91-105, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28558343

ABSTRACT

We have used Electron Tomography (ET) to reveal the detailed three-dimensional structure of particulate hydrogels, a material category common in e.g. controlled release, food science, battery and biomedical applications. A full understanding of the transport properties of these gels requires knowledge about the pore structure and in particular the interconnectivity in three dimensions, since the transport takes the path of lowest resistance. The image series for ET were recorded using High-Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM). We have studied three different particulate silica hydrogels based on primary particles with sizes ranging from 3.6nm to 22nm and with pore-size averages from 18nm to 310nm. Here, we highlight the nanostructure of the particle network and the interpenetrating pore network in two and three dimensions. The interconnectivity and distribution of width of the porous channels were obtained from the three-dimensional tomography studies while they cannot unambiguously be obtained from the two-dimensional data. Using ET, we compared the interconnectivity and accessible pore volume fraction as a function of pore size, based on direct images on the nanoscale of three different hydrogels. From this comparison, it was clear that the finest of the gels differentiated from the other two. Despite the almost identical flow properties of the two finer gels, they showed large differences concerning the accessible pore volume fraction for probes corresponding to their (two-dimensional) mean pore size. Using 2D pore size data, the finest gel provided an accessible pore volume fraction of over 90%, but for the other two gels the equivalent was only 10-20%. However, all the gels provided an accessible pore volume fraction of 30-40% when taking the third dimension into account.

8.
Nanoscale ; 9(12): 4227-4235, 2017 Mar 23.
Article in English | MEDLINE | ID: mdl-28290585

ABSTRACT

The widespread use of magnetic nanoparticles in the biotechnical sector puts new demands on fast and quantitative characterization techniques for nanoparticle dispersions. In this work, we report the use of asymmetric flow field-flow fractionation (AF4) and ferromagnetic resonance (FMR) to study the properties of a commercial magnetic nanoparticle dispersion. We demonstrate the effectiveness of both techniques when subjected to a dispersion with a bimodal size/magnetic property distribution: i.e., a small superparamagnetic fraction, and a larger blocked fraction of strongly coupled colloidal nanoclusters. We show that the oriented attachment of primary nanocrystals into colloidal nanoclusters drastically alters their static, dynamic, and magnetic resonance properties. Finally, we show how the FMR spectra are influenced by dynamical effects; agglomeration of the superparamagnetic fraction leads to reversible line-broadening; rotational alignment of the suspended nanoclusters results in shape-dependent resonance shifts. The AF4 and FMR measurements described herein are fast and simple, and therefore suitable for quality control procedures in commercial production of magnetic nanoparticles.

9.
Psychol Med ; 46(15): 3095-3104, 2016 11.
Article in English | MEDLINE | ID: mdl-27534695

ABSTRACT

BACKGROUND: The concept of cognitive reserve (CR) hypothesizes that intellectually stimulating activities provide resilience against brain pathology/disease. Whereas brain abnormalities and cognitive impairment are frequently reported in bipolar disorder (BD), it is unknown whether the impact of brain alterations can be lessened by higher CR in BD. METHOD: We tested if higher CR would reduce the influence of total volumes of deep white matter hypointensities (WMH), ventricular cerebrospinal fluid (CSF), and prefrontal cortex on memory, executive, and attention/speed functions in patients with BD (n = 75). Linear regression models with interaction terms for CR and brain volumes were applied to directly test if CR reduces the influence of brain pathology on cognitive domains. RESULTS: CR reduced the influence of total volumes of deep WMH (ß = -0.38, Q = 0.003) and ventricular CSF (ß = -41, Q = 006) on executive functions. CONCLUSIONS: The interactions between CR and total volumes of deep WMH/ventricular CSF appear to account for executive functioning in BD. The results suggest that the concept of CR is applicable in BD. Higher reserve capacity in BD alters the relationship between brain pathology and clinical presentation.


Subject(s)
Bipolar Disorder/psychology , Brain/diagnostic imaging , Cerebrospinal Fluid/diagnostic imaging , Cognitive Dysfunction/psychology , Cognitive Reserve , Prefrontal Cortex/diagnostic imaging , White Matter/diagnostic imaging , Adult , Attention/physiology , Bipolar Disorder/diagnostic imaging , Bipolar Disorder/physiopathology , Brain/pathology , Case-Control Studies , Cognitive Dysfunction/diagnostic imaging , Cognitive Dysfunction/physiopathology , Executive Function , Female , Humans , Linear Models , Magnetic Resonance Imaging , Male , Memory/physiology , Middle Aged , Organ Size , Prefrontal Cortex/pathology , Reaction Time , White Matter/pathology , Young Adult
10.
Ann Oncol ; 27(8): 1532-8, 2016 08.
Article in English | MEDLINE | ID: mdl-27194814

ABSTRACT

BACKGROUND: A mutation found in the BRCA1 or BRCA2 gene of a breast tumor could be either germline or somatically acquired. The prevalence of somatic BRCA1/2 mutations and the ratio between somatic and germline BRCA1/2 mutations in unselected breast cancer patients are currently unclear. PATIENTS AND METHODS: Paired normal and tumor DNA was analyzed for BRCA1/2 mutations by massively parallel sequencing in an unselected cohort of 273 breast cancer patients from south Sweden. RESULTS: Deleterious germline mutations in BRCA1 (n = 10) or BRCA2 (n = 10) were detected in 20 patients (7%). Deleterious somatic mutations in BRCA1 (n = 4) or BRCA2 (n = 5) were detected in 9 patients (3%). Accordingly, about 1 in 9 breast carcinomas (11%) in our cohort harbor a BRCA1/2 mutation. For each gene, the tumor phenotypes were very similar regardless of the mutation being germline or somatically acquired, whereas the tumor phenotypes differed significantly between wild-type and mutated cases. For age at diagnosis, the patients with somatic BRCA1/2 mutations resembled the wild-type patients (median age at diagnosis, germline BRCA1: 41.5 years; germline BRCA2: 49.5 years; somatic BRCA1/2: 65 years; wild-type BRCA1/2: 62.5 years). CONCLUSIONS: In a population without strong germline founder mutations, the likelihood of a BRCA1/2 mutation found in a breast carcinoma being somatic was ∼1/3 and germline 2/3. This may have implications for treatment and genetic counseling.


Subject(s)
BRCA1 Protein/genetics , BRCA2 Protein/genetics , Breast Neoplasms/genetics , Adult , Aged , Breast Neoplasms/epidemiology , Breast Neoplasms/pathology , Female , Genetic Predisposition to Disease , Germ-Line Mutation , Humans , Middle Aged , Mutation , Sweden/epidemiology
11.
J Microsc ; 262(1): 102-11, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26584453

ABSTRACT

Studies on colloidal aggregation have brought forth theories on stability of colloidal gels and models for aggregation dynamics. Still, a complete link between developed frameworks and obtained laboratory observations has to be found. In this work, aggregates of silica nanoparticles (20 nm) are studied using diffusion limited cluster aggregation (DLCA) and reaction limited cluster aggregation (RLCA) models. These processes are driven by the probability of particles to aggregate upon collision. This probability of aggregation is one in the DLCA and close to zero in the RLCA process. We show how to study the probability of aggregation from static micrographs on the example of a silica nanoparticle gel at 9 wt%. The analysis includes common summary functions from spatial statistics, namely the empty space function and Ripley's K-function, as well as two newly developed summary functions for cluster analysis based on graph theory. One of the new cluster analysis functions is related to the clustering coefficient in communication networks and the other to the size of a cluster. All four topological summary statistics are used to quantitatively compare in plots and in a least-square approach experimental data to cluster aggregation simulations with decreasing probabilities of aggregation. We study scanning transmission electron micrographs and utilize the intensity-mass thickness relation present in such images to create comparable micrographs from three-dimensional simulations. Finally, a characterization of colloidal silica aggregates and simulated structures is obtained, which allows for an evaluation of the cluster aggregation process for different aggregation scenarios. As a result, we find that the RLCA process fits the experimental data better than the DLCA process.

12.
J Microsc ; 253(2): 166-70, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24382203

ABSTRACT

In this study, we investigate the functional behaviour of the intensity in high-angle annular dark field scanning transmission electron micrograph images. The model material is a silica particle (20 nm) gel at 5 wt%. By assuming that the intensity response is monotonically increasing with increasing mass thickness of silica, an estimate of the functional form is calculated using a maximum likelihood approach. We conclude that a linear functional form of the intensity provides a fair estimate but that a power function is significantly better for estimating the amount of silica in the z-direction. The work adds to the development of quantifying material properties from electron micrographs, especially in the field of tomography methods and three-dimensional quantitative structural characterization from a scanning transmission electron micrograph. It also provides means for direct three-dimensional quantitative structural characterization from a scanning transmission electron micrograph.

13.
Nat Commun ; 4: 1838, 2013.
Article in English | MEDLINE | ID: mdl-23673623

ABSTRACT

The observation of a high-mobility two-dimensional electron gas between two insulating complex oxides, especially LaAlO3/SrTiO3, has enhanced the potential of oxides for electronics. The occurrence of this conductivity is believed to be driven by polarization discontinuity, leading to an electronic reconstruction. In this scenario, the crystal orientation has an important role and no conductivity would be expected, for example, for the interface between LaAlO3 and (110)-oriented SrTiO3, which should not have a polarization discontinuity. Here we report the observation of unexpected conductivity at the LaAlO3/SrTiO3 interface prepared on (110)-oriented SrTiO3, with a LaAlO3-layer thickness-dependent metal-insulator transition. Density functional theory calculation reveals that electronic reconstruction, and thus conductivity, is still possible at this (110) interface by considering the energetically favourable (110) interface structure, that is, buckled TiO2/LaO, in which the polarization discontinuity is still present. The conductivity was further found to be strongly anisotropic along the different crystallographic directions with potential for anisotropic superconductivity and magnetism, leading to possible new physics and applications.

14.
Ambio ; 42(3): 309-19, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23288617

ABSTRACT

The REDD+ scheme of the United Nations intends to offer developing countries financial incentives to reduce the rates of deforestation and forest degradation for reducing global CO2 emissions. This is combined with building carbon stocks in existing wooded ecosystems and fostering other soil, biodiversity and water conservation objectives. Successful application of REDD+ to the Xylophone Triangle of West Africa faces substantial challenges and risks to both meeting REDD+ objectives and to the local people's rights and livelihoods. The transnationality of the culturally coherent area requires collaboration of three national governments. The opportunities, however, are great to capitalize on the region's biodiversity, the well-developed traditional ecological knowledge and the use of local medicinal plants as an integral part of the agro-ecosystem. Possibilities open to, not only sequester carbon, but also to increase the resilience of the ecosystem and of independent rural livelihoods in the face of climate change and globalization.


Subject(s)
Climate Change , Conservation of Natural Resources , Forestry , Trees , Africa, Western , Biodiversity , Carbon Dioxide/analysis , Conservation of Natural Resources/economics , Conservation of Natural Resources/methods , Conservation of Natural Resources/trends , Developing Countries , Ecosystem , Forestry/economics , Forestry/methods , Forestry/trends , Internationality , Plants, Medicinal/growth & development , Rural Population , Trees/growth & development
15.
Gait Posture ; 37(2): 165-71, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22818116

ABSTRACT

Walking deterioration occurs frequently in adults with spastic bilateral cerebral palsy (CP), but their gait characteristics are largely unknown. The study aims were (1) to compare selected gait analysis variables between those reporting and those not reporting walking deterioration, and (2) to characterise the overall gait deviations and classify the gait patterns. Participants (N=16) were recruited from a follow-up study, had spastic bilateral CP, <40 years in 2006, GMFCS levels I-III, and could walk at least 10 m without support. Eight reported walking deterioration (cases) and eight did not (controls). A theoretical framework linking work of walking, fatigue and deterioration in walking was developed. It was hypothesised that higher energy requirements during gait and larger gait deviations would be associated with deterioration in walking. Three-dimensional gait analysis was used to obtain centre of mass work, mechanical joint work, lower limb kinematics, movement analysis profile (MAP), and gait profile scores (GPS). There were no differences between the cases and controls in centre of mass work, joint work, or in the GPS. The largest MAP deviations were seen in sagittal pelvis, hip, and knee angles and foot progression. Crouch and asymmetric gait were common patterns. Walking deterioration could not be explained by these work and kinematic variables. An individual's perception of deterioration in walking is subjective, and may be experienced and interpreted differently across people. Larger, longitudinal studies on the natural history of walking in spastic CP are needed. Qualitative studies on the subjective experiences of walking deterioration are also warranted.


Subject(s)
Cerebral Palsy/physiopathology , Gait Disorders, Neurologic/physiopathology , Adult , Biomechanical Phenomena , Case-Control Studies , Disability Evaluation , Disease Progression , Female , Follow-Up Studies , Humans , Male
16.
Psychooncology ; 21(8): 886-95, 2012 Aug.
Article in English | MEDLINE | ID: mdl-21557383

ABSTRACT

OBJECTIVE: Attachment theory has received much interest lately in relation to how adults cope with stress and severe illness. The aim of this study was using the experiences of patients and family members to explore palliative home care as a 'secure base' (a central concept within the theory). METHODS: Twelve patients and 14 family members were interviewed during ongoing palliative home care. The interviews were analysed with deductive qualitative content analysis. RESULTS: Informants expressed the relevance of sensing security during palliative home care because death and dying were threats that contributed to vulnerability. Palliative home care could foster a feeling of security and provide a secure base. This was facilitated when informants had trust in staff (e.g. due to availability and competence in providing symptom relief), felt recognised as individuals and welcomed to contact the team in times of needs. Being comfortable, informed and having an everyday life also contributed to a perception of palliative home care as a secure base. Family members stressed the importance of being relieved from responsibilities that were too heavy. The underlying meanings of experiencing palliative home care as a secure base involved gaining a sense of control and of inner peace, perceiving that despite a demanding and changed life situation, one could continue partially being oneself and having something to hope for, even if this no longer concerned cure for the ill person. CONCLUSIONS: Important aspects of palliative home care as providing a secure base were identified and these have implications for clinical practice.


Subject(s)
Adaptation, Psychological , Family/psychology , Home Care Services , Neoplasms/psychology , Object Attachment , Palliative Care/psychology , Adult , Aged , Female , Humans , Male , Middle Aged , Psychological Theory , Qualitative Research
17.
Dement Geriatr Cogn Disord ; 31(2): 132-8, 2011.
Article in English | MEDLINE | ID: mdl-21293123

ABSTRACT

BACKGROUND: Mild cognitive impairment (MCI) is a heterogeneous condition suggested as a prodromal state of Alzheimer's disease (AD) and subcortical vascular dementia (SVD). Recent findings suggest that white matter lesions (WML) may be associated with hippocampal atrophy. The objective of the study was to examine hippocampal and WML volumes in MCI patients and to examine if WML were linked to hippocampal atrophy. METHODS: The Gothenburg MCI study is a clinically based longitudinal study with biennial clinical assessments. The participants (n = 166) consist of 92 patients with stable MCI, 30 patients with converting MCI, and 44 healthy controls. WML volumes was measured manually using MRIcron. Automated segmentation of hippocampal and total white matter volumes was performed using FreeSurfer. RESULTS: The patients converting from MCI to dementia had reduced hippocampal volume. Stable MCI patients had fewer WML and converting MCI patients had more WML compared to controls. Hippocampal volume was only correlated to WML volume (ρ = 0.57; p < 0.01) in the quartile (n = 42) with the most WML. CONCLUSIONS: Hippocampal atrophy is present in both AD and SVD. Hippocampal volume was associated with WML volume only in the high WML quartile, suggesting that the WML volume must reach a threshold before hippocampal atrophy is seen.


Subject(s)
Brain/pathology , Cognition Disorders/pathology , Hippocampus/pathology , Aged , Alzheimer Disease/pathology , Alzheimer Disease/psychology , Apolipoproteins E/genetics , Atrophy , Cognition Disorders/psychology , Dementia, Vascular/pathology , Dementia, Vascular/psychology , Educational Status , Female , Humans , Longitudinal Studies , Magnetic Resonance Imaging , Male , Middle Aged , Neuropsychological Tests
18.
Micron ; 42(4): 324-9, 2011 Jun.
Article in English | MEDLINE | ID: mdl-20943407

ABSTRACT

Sr3Ru2O7/Sr2RuO4 eutectic system is investigated by electron backscattering diffraction (EBSD) and X-ray diffraction (XRD). The eutectic growth enables the solidification of the two phases in an ordered lamellar pattern extending along the growth direction, namely the b-axis direction. The eutectic material thus provides in the a-c plane two distinct interfaces having different microstructures with respect to the growth direction. Our analysis shows that, across the inplane c-axis direction (characterized by a poor lattice matching), the b-axis orientation is not constant at the individual interfaces, showing an orientation spread of about 5°. However, across the in-plane a-axis direction (characterized by a good lattice matching), the b-axis orientation does not change within a few tenths of degree (about 0.25°). Such information at nanoscale is also verified on a macroscopic level by standard XRD investigation.

19.
Nano Lett ; 10(12): 4824-9, 2010 Dec 08.
Article in English | MEDLINE | ID: mdl-21080664

ABSTRACT

We have developed a new method to fabricate biepitaxial YBa2 Cu3 O7-δ (YBCO) Josephson junctions at the nanoscale, allowing junctions widths down to 100 nm and simultaneously avoiding the typical damage in grain boundary interfaces due to conventional patterning procedures. By using the competition between the superconducting YBCO and the insulating Y2 BaCuO5 phases during film growth, we formed nanometer sized grain boundary junctions in the insulating Y2 BaCuO5 matrix as confirmed by high-resolution transmission electron microscopy. Electrical transport measurements give clear indications that we are close to probing the intrinsic properties of the grain boundaries.

20.
Dement Geriatr Cogn Disord ; 29(4): 294-300, 2010.
Article in English | MEDLINE | ID: mdl-20389071

ABSTRACT

BACKGROUND: Mild cognitive impairment (MCI) is a heterogeneous condition, and the prognosis differs within the group. Recent findings suggest that hippocampal volumetry and CSF biomarkers can be used to predict which MCI patients have an underlying neurodegenerative disorder. OBJECTIVE: To examine the combined predictive value of hippocampal volume and CSF levels of total tau (T-tau) and beta-amyloid(42) (Abeta(42)) in stable and converting MCI patients. The participants (n = 68) included patients with MCI at baseline and who converted to dementia by the time of the 2-year follow-up (n = 21), stable MCI patients (n = 21) and healthy controls (n = 26). METHODS: The Göteborg MCI study is a clinically based longitudinal study with biannual clinical assessments. Hippocampal volumetry was performed manually, based on data from the 0.5-tesla MRI investigations at baseline. Baseline CSF levels of T-tau and Abeta(42) were measured using commercially available, enzyme-linked immunosorbent assays. RESULTS: The converting MCI group had significantly smaller left hippocampi, lower CSF Abeta(42) and higher T-tau compared to both the stable MCI group and the healthy controls. Multivariate analysis revealed that a combination of the variables outperformed the prognostic ability of the separate variables. CONCLUSIONS: Hippocampal volumes supplement the prognostic accuracy of CSF Abeta(42) and T-tau in MCI.


Subject(s)
Biomarkers/blood , Cognition Disorders/cerebrospinal fluid , Cognition Disorders/diagnosis , Hippocampus/pathology , Magnetic Resonance Imaging , Aged , Aged, 80 and over , Amyloid beta-Peptides/cerebrospinal fluid , Cognition Disorders/psychology , Enzyme-Linked Immunosorbent Assay , Female , Humans , Longitudinal Studies , Male , Middle Aged , Peptide Fragments/cerebrospinal fluid , Predictive Value of Tests , Severity of Illness Index , tau Proteins/cerebrospinal fluid
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