770 research outputs found
Preliminary Evidence of Increased Hippocampal Myelin Content in Veterans with Posttraumatic Stress Disorder.
Recent findings suggest the formation of myelin in the central nervous system by oligodendrocytes is a continuous process that can be modified with experience. For example, a recent study showed that immobilization stress increased oligodendrogensis in the dentate gyrus of adult rat hippocampus. Because changes in myelination represents an adaptive form of brain plasticity that has a greater reach in the adult brain than other forms of plasticity (e.g., neurogenesis), the objective of this "proof of concept" study was to examine whether there are differences in myelination in the hippocampi of humans with and without post-traumatic stress disorder (PTSD). We used the ratio of T1-weighted/T2-weighted magnetic resonance image (MRI) intensity to estimate the degree of hippocampal myelination in 19 male veterans with PTSD and 19 matched trauma-exposed male veterans without PTSD (mean age: 43 ± 12 years). We found that veterans with PTSD had significantly more hippocampal myelin than trauma-exposed controls. There was also found a positive correlation between estimates of hippocampal myelination and PTSD and depressive symptom severity. To our knowledge, this is the first study to examine hippocampal myelination in humans with PTSD. These results provide preliminary evidence for stress-induced hippocampal myelin formation as a potential mechanism underlying the brain abnormalities associated with vulnerability to stress
The construction of one-bone forearm with side-to-side distal radioulnar bifurcation synostosis operation for congenital pseudarthrosis of the radius
The congenital radius pseudarthrosis is a rare condition which’s treatment is difficult. There were many reported surgical options for this situation. One of them is construction of one-bone in forearm. Here, we presented a seven years-old boy who has instability and defective congenital radius pseudarthrosis in forearm that treated with side-to-side distal radioulnar bifurcation synostosis technique preserving the distal radioulnar joint, and obtained good functional results
CSF protein biomarkers predicting longitudinal reduction of CSF β-amyloid42 in cognitively healthy elders.
β-amyloid (Aβ) plaque accumulation is a hallmark of Alzheimer's disease (AD). It is believed to start many years prior to symptoms and is reflected by reduced cerebrospinal fluid (CSF) levels of the peptide Aβ1-42 (Aβ42). Here we tested the hypothesis that baseline levels of CSF proteins involved in microglia activity, synaptic function and Aβ metabolism predict the development of Aβ plaques, assessed by longitudinal CSF Aβ42 decrease in cognitively healthy people. Forty-six healthy people with three to four serial CSF samples were included (mean follow-up 3 years, range 2-4 years). There was an overall reduction in Aβ42 from a mean concentration of 211-195 pg ml(-1) after 4 years. Linear mixed-effects models using longitudinal Aβ42 as the response variable, and baseline proteins as explanatory variables (n=69 proteins potentially relevant for Aβ metabolism, microglia or synaptic/neuronal function), identified 10 proteins with significant effects on longitudinal Aβ42. The most significant proteins were angiotensin-converting enzyme (ACE, P=0.009), Chromogranin A (CgA, P=0.009) and Axl receptor tyrosine kinase (AXL, P=0.009). Receiver-operating characteristic analysis identified 11 proteins with significant effects on longitudinal Aβ42 (largely overlapping with the proteins identified by linear mixed-effects models). Several proteins (including ACE, CgA and AXL) were associated with Aβ42 reduction only in subjects with normal baseline Aβ42, and not in subjects with reduced baseline Aβ42. We conclude that baseline CSF proteins related to Aβ metabolism, microglia activity or synapses predict longitudinal Aβ42 reduction in cognitively healthy elders. The finding that some proteins only predict Aβ42 reduction in subjects with normal baseline Aβ42 suggest that they predict future development of the brain Aβ pathology at the earliest stages of AD, prior to widespread development of Aβ plaques
Outcomes of the chondral lesions of knee treated by microfracture technique and effective factors on the results
Objectives: The aim of this study was to evaluate the results of the microfracture technique in the treatment of chondral lesions.Materials and methods: A retrospective study was performed in 26 patients who had treated by arthroscopic microfracture technique for chondral lesions in the femoral condils between January 2003 and 2007september in our department. There were 11 females and 15 males with mean age of 37.2 years (range from 23 to 56 years). The average time between beginning of complaints and operation were 9.7 months (range from 3 to 35 months). The average of chondral lesions size were 1,6 cm2 (range from 0.7 to 2.4 mm2). The average follow-up period was 24.3 months (ranged from 10 to 44 months). Patients assessed according to subjective patient satisfaction and Lisholm scale at preoperative and postoperative time.Results: The mean Lysholm score increased from a preoperative 56.9 (range from 43 to 72) to a postoperative 77.9 (range from 62 to 100) (p<0.05). The rating was excellent in 9 patients (34.6%), good in 7 (27%) and fair in 10 (38.4%) according to Lysholm scale. All patients were satisfied with their knee function. The results of MRI taken at postoperative sixth month were proportional with patient’s satisfaction and Lysholm scores.Conclusion: Patients with excellent or good results had short symptom period, small chondral lesion and young age. Applied early microfracture technique in treatment of chondral lesions was a low cost, effective and successful treatment modalit
Şırnak kömür madeni atık şeyl yığın tasarımı ve GEO5 FEM stabilite risk değerlendirme
Yığınların GEO 5 FEM programı ile sınır ağ modellemesi ve stabilite analizleri yapılmıştır. S1, S2, S3 ve S4 no’lu heyelanların geliştiği yamaçların 1/1000 ölçekli topoğrafik haritaları arazi çalışmalarıyla hazırlanmış ve yığının yapısal kesitleri çıkarılmıştır. Yığından alınan zemin örnekleri üzerinde yapılan laboratuar deneyleri ile yamaç molozunun fiziksel ve mekanik özellikleri; Efektif içsel sürtünme açısı (φ′°) 17°-22.5°, efektif kohezyonu (c′) 0,5-1,8 kg/cm2, maksimum kuru birim hacim ağırlık 1.87-2.25 g/cm3, doygun birim hacim ağırlık 1.78-2.43 g/cm3, doğal birim hacim ağırlık 1.9-2.35 g/cm3, kuru birim hacim ağırlık 1.97-2.40 g/cm3, tane birim hacim ağırlığı (γs) 2.47-2.60 g/cm3, permeabilite katsayısı 1x10-4 - 6.5x10-4 cm/s, olarak belirlenmiş ve ayrıca tane dağılım testleri yapılmıştır. Yamaçların hazırlanan kesitlerinde, GEO 5 FEM programında olası kritik gerilme yüzeyleri irdelenmiştir. Yamaç kaymasını engelleyen kaya dolgusu topuk tasarımları yapılmıştır. Yığın malzemenin belirlenen jeoteknik özellikleri de kullanılarak GEO5 FEM ve stabilite programı aracılığı ile güvenlik katsayıları belirlenmiş ve hesaplanan değerlere göre S3 ve S4 no’lu yamaçların stabil oldukları S1 ve S2 no’lu yamacın ise stabil olmadığı tespit edilmiştir. Kalker topuk kaya dolguları ile GEO5 FEM programı aracılığı ile stabilitenin sağlandığı belirlenmiştir.In Sirnak, for mining landfills geotechnical stability analyses were conducted by GEO5 FEM. An area of near 7 km2 study area and the surrounding area has been 1/1.000 scale engineering geological map, as well as the drilling and laboratory geotechnical engineering properties of materials are determined by experiments. S1, S2, S3 and S4 hillsides to develop landslide slopes 1/1000 scale topographic maps and geological field studies prepared by processing units on the map the geological cross-sections were prepared. By laboratory experiments carried out on soil samples taken from fields of physical and mechanical properties of slope debris; effective angle of internal friction (φ '°) 17° -22.5°, effective cohesion (c') 0,5-1,8 kg/cm2, the maximum dry unit weight 1.87 -2.25 g/cm3 1.78-2.43 g/cm3 saturated unit weight, unit weight 1.9-2.35 g/cm3 1.97-2.40 g/cm3, unit weight (γs) 2.47-2.60 g / cm3, permeability coefficient of 1x10-4 - 6.5x10-4 cm / s, the particle distribution were determined and also tested. Geological sections prepared slopes, the geostatical properties of the material were determined by the trial slip surfaces. Rock fill pillar design were made and calculated according to the values via the S3 and S4 are stable hillsides, S1, S2 have been found that to close the unstable slope. Stability was performed by limestone pillar rockfills on hazardous dumps
Soil liquefaction potential in Eskişehir, NW Turkey
Liquefaction is one of the critical problems in geotechnical engineering. High ground water levels and alluvial soils have a high potential risk for damage due to liquefaction, especially in seismically active regions. Eskişehir urban area, studied in this article, is situated within the second degree earthquake region on the seismic hazard zonation map of Turkey and is surrounded by Eskişehir, North Anatolian, Kütahya and Simav Fault Zones. Geotechnical investigations are carried out in two stages: field and laboratory. In the first stage, 232 boreholes in different locations were drilled and Standard Penetration Test (SPT) was performed. Test pits at 106 different locations were also excavated to support geotechnical data obtained from field tests. In the second stage, experimental studies were performed to determine the Atterberg limits and physical properties of soils. Liquefaction potential was investigated by a simplified method based on SPT. A scenario earthquake of magnitude <i>M</i>=6.4, produced by Eskişehir Fault Zone, was used in the calculations. Analyses were carried out for PGA levels at 0.19, 0.30 and 0.47 g. The results of the analyses indicate that presence of high ground water level and alluvial soil increase the liquefaction potential with the seismic features of the region. Following the analyses, liquefaction potential maps were produced for different depth intervals and can be used effectively for development plans and risk management practices in Eskişehir
Electrical Impedance Tomography of Translationally Uniform Cylindrical Objects with General Cross-Sectional Boundaries
An algorithm is developed for electrical impedance tomography (EIT) of finite cylinders with general cross-sectional boundaries and translationally uniform conductivity distributions. The electrodes for data collection are assumed to be placed around a cross-sectional plane,- therefore the axial variation of the boundary conditions and also the potential field are expanded in Fourier series. For each Fourier component a two-dimensional (2-D) partial differential equation is derived. Thus the 3-D forward problem is solved as a succession of 2-D problems and it is shown that the Fourier series can be truncated to provide substantial saving in computation time. The finite element method is adopted and the accuracy of the boundary potential differences (gradients) thus calculated is assessed by comparison to results obtained using cylindrical harmonic expansions for circular cylinders. A 1016-element and 541-node mesh is found to be optimal. For a given cross-sectional boundary, the ratios of the gradients calculated for both 2-D and 3-D homogeneous objects are formed. The actual measurements from the 3-D object are multiplied by these ratios and thereafter the tomographic image is obtained by the 2-D iterative equipotential lines method. The algorithm is applied to data collected from phantoms, and the errors incurred from the several assumptions of the method are investigated. The method is also applied to humans and satisfactory images are obtained. It is argued that the method finds an “equivalent” translationally uniform object, the calculated gradients for which are the same as the actual measurements collected. In the absence of any other information about the translational variation of conductance this method is especially suitable for body parts with some translational uniformity. © 1990 IEE
Revealing Individual Neuroanatomical Heterogeneity in Alzheimer Disease Using Neuroanatomical Normative Modeling
BACKGROUND AND OBJECTIVES: Alzheimer's Disease (AD) is highly heterogeneous, with marked individual differences in clinical presentation and neurobiology. To explore this, we employed neuroanatomical normative modelling to index regional patterns of variability in cortical thickness. We aimed to characterise individual differences and outliers in cortical thickness in patients with AD, people with mild cognitive impairment (MCI) and controls. Furthermore, we assessed the relationships between cortical thickness heterogeneity and cognitive function, amyloid-beta, phosphor-tau, ApoE genotype. Finally, we examined whether cortical thickness heterogeneity was predictive of conversion from MCI to AD. METHODS: Cortical thickness measurements across 148 brain regions were obtained from T1-weighted MRI scans from 62 sites of the Alzheimer's Disease Neuroimaging Initiative. AD was determined by clinical and neuropsychological examination with no comorbidities present. MCI participants had reported memory complaints, and controls were cognitively normal. A neuroanatomical normative model indexed cortical thickness distributions using a separate healthy reference dataset (n= 33,072), employing hierarchical Bayesian regression to predict cortical thickness per region using age and sex, whilst adjusting for site noise. Z-scores per region were calculated, resulting in a z-score 'brain map' per participant. Regions with z-scores <-1.96 were classified as outliers. RESULTS: Patients with AD (n=206) had a median of 12 outlier regions (out of a possible 148), with the highest proportion of outliers (47%) in the parahippocampal gyrus. For 62 regions, over 90% of these patients had cortical thicknesses within the normal range. Patients with AD had more outlier regions than people with MCI (n=662) or controls (n=159) [F(2, 1022) = 95.39), P = 2.0×10-16]. They were also more dissimilar to each other than people with MCI or controls [F(2, 1024) = 209.42, P = 2.2×10-16]. A greater number of outlier regions was associated with worse cognitive function, CSF protein concentrations and an increased risk of converting from MCI to AD within three years (HR = 1.028, 95% CI[1.016,1.039], P =1.8×10-16). DISCUSSION: Individualised normative maps of cortical thickness highlight the heterogeneous impact of AD on the brain. Regional outlier estimates have the potential to be a marker of disease and could be used to track an individual's disease progression or treatment response in clinical trials
Europe’s Farm to Fork Strategy and Its Commitment to Biotechnology and Organic Farming: Conflicting or Complementary Goals?
The European Commission's Farm to Fork (F2F) strategy, under the European Green Deal, acknowledges that innovative techniques, including biotechnology, may play a role in increasing sustainability. At the same time, organic farming will be promoted, and at least 25% of the EU's agricultural land shall be under organic farming by 2030. How can both biotechnology and organic farming be developed and promoted simultaneously to contribute to achieving the Sustainable Development Goals (SDGs)? We illustrate that achieving the SDGs benefits from the inclusion of recent innovations in biotechnology in organic farming. This requires a change in the law. Otherwise, the planned increase of organic production in the F2F strategy may result in less sustainable, not more sustainable, food systems
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