379 research outputs found
The organization of 2,3-iron-naphthalocyanine molecules on substrate as revealed by scanning tunneling microscopy
Surface morphology of thin molecular layer of 2,3-Iron-naphthalocyanine (2,3 FeNPc) was studied by scanning tunneling microscopy (STM) at the ambient conditions. Organic layer with thickness of 40 nm was vapour phase deposited on amorphous carbon substrate. The STM images have revealed the pecularities of surface molecular organization from large range (hundreds of nm) down to atomic scale. Arrays of locally ordered linear stuctures have been distinguished as the main morphological features of the examined surface. At several places the well-ordered STM patterns have been distinguished at the atomic scale. They can be described as stacks of periodicity approximatelly 0.4 nm in a row and 1.5 nm between stacks. These results can be explained by arrangement of 2,3-FeNPh molecules in stacks with a main plane being perpendicular to the substrate surface
Physiological Appearance of Hybrid FDG-Positron Emission Tomography/Computed Tomography Imaging Following Uncomplicated Endovascular Aneurysm Sealing Using the Nellix Endoprosthesis
Purpose: To investigate the physiological uptake of hybrid fluorine-18-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) before and after an uncomplicated endovascular aneurysm sealing (EVAS) procedure as a possible tool to diagnose EVAS graft infection and differentiate from postimplantation syndrome. Materials and Methods: Eight consecutive male patients (median age 78 years) scheduled for elective EVAS were included in the prospective study (ClinicalTrials.gov identifier NCT02349100). FDG-PET/CT scans were performed in all patients before the procedure and 6 weeks after EVAS. The abdominal aorta was analyzed in 4 regions: suprarenal, infrarenal neck, aneurysm sac, and iliac. The following parameters were obtained for each region: standard uptake value (SUV), tissue to background ratio (TBR), and visual examination of FDG uptake to ascertain its distribution. Demographic data were obtained from medical files and scored based on reporting standards. Results: Visual examination showed no difference between pre- and postprocedure FDG uptake, which was homogenous. In the suprarenal region no significant pre- and postprocedure differences were observed for the SUV and TBR parameters. The infrarenal neck region showed a significant decrease in the SUV and no significant decrease in the TBR. The aneurysm sac and iliac regions both showed a significant decrease in SUV and TBR between the pre- and postprocedure scans. Conclusion: Physiological FDG uptake after EVAS was stable or decreased with regard to the preprocedure measurements. Future research is needed to assess the applicability and cutoff values of FDG-PET/CT scanning to detect endograft infection after EVAS
Physiological Appearance of Hybrid FDG–Positron Emission Tomography/Computed Tomography Imaging Following Uncomplicated Endovascular Aneurysm Sealing Using the Nellix Endoprosthesis
Purpose: To investigate the physiological uptake of hybrid fluorine-18-fluorodeoxyglucose (FDG)–positron emission tomography/computed tomography (PET/CT) before and after an uncomplicated endovascular aneurysm sealing (EVAS) procedure as a possible tool to diagnose EVAS graft infection and differentiate from postimplantation syndrome.Materials and Methods: Eight consecutive male patients (median age 78 years) scheduled for elective EVAS were included in the prospective study (ClinicalTrials.gov identifier NCT02349100). FDG-PET/CT scans were performed in all patients before the procedure and 6 weeks after EVAS. The abdominal aorta was analyzed in 4 regions: suprarenal, infrarenal neck, aneurysm sac, and iliac. The following parameters were obtained for each region: standard uptake value (SUV), tissue to background ratio (TBR), and visual examination of FDG uptake to ascertain its distribution. Demographic data were obtained from medical files and scored based on reporting standards.Results: Visual examination showed no difference between pre- and postprocedure FDG uptake, which was homogenous. In the suprarenal region no significant pre- and postprocedure differences were observed for the SUV and TBR parameters. The infrarenal neck region showed a significant decrease in the SUV and no significant decrease in the TBR. The aneurysm sac and iliac regions both showed a significant decrease in SUV and TBR between the pre- and postprocedure scans.Conclusion: Physiological FDG uptake after EVAS was stable or decreased with regard to the preprocedure measurements. Future research is needed to assess the applicability and cutoff values of FDG-PET/CT scanning to detect endograft infection after EVAS
Halfvortices in flat nanomagnets
We discuss a new type of topological defect in XY systems where the O(2)
symmetry is broken in the presence of a boundary. Of particular interest is the
appearance of such defects in nanomagnets with a planar geometry. They are
manifested as kinks of magnetization along the edge and can be viewed as
halfvortices with winding numbers \pm 1/2. We argue that halfvortices play a
role equally important to that of ordinary vortices in the statics and dynamics
of flat nanomagnets. Domain walls found in experiments and numerical
simulations are composite objects containing two or more of these elementary
defects. We also discuss a closely related system: the two-dimensional smectic
liquid crystal films with planar boundary condition.Comment: 7 pages, 8 figures, To appear as a chapter in Les Houches summer
school on Quantum Magnetis
SDG indicator 3.b.3 - an analysis of its robustness and challenges for measuring access to medicines for children
BACKGROUND: Sustainable Development Goal (SDG) indicator 3.b.3 monitors progress in medicines' accessibility for adults and has significant limitations when applying to medicines for children. An adapted indicator methodology was developed to fill this gap, but no proof of its robustness exists. We provide this evidence through sensitivity analyses. METHODS: Data on availability and prices of child medicines from ten historical datasets were combined to create datasets for analysis: Dataset 1 (medicines selected at random) and Dataset 2 (preference given to available medicines, to better capture affordability of medicines). A base case scenario and univariate sensitivity analyses were performed to test critical components of the methodology, including the new variable of number of units needed for treatment (NUNT), disease burden (DB) weighting, and the National Poverty Line (NPL) limits. Additional analyses were run on a continuously smaller basket of medicines to explore the minimum number of medicines required. Mean facility scores for access were calculated and compared. RESULTS: The mean facility score for Dataset 1 and Dataset 2 within the base case scenario was 35.5% (range 8.0-58.8%) and 76.3% (range 57.2-90.6%). Different NUNT scenarios led to limited variations in mean facility scores of + 0.1% and -0.2%, or differences of + 4.4% and -2.1% at the more critical NPL of 5.50 the differences were + 5.0 and -2.0%. Different approaches for weighting for DB induced considerable fluctuations of 9.0% and 11.2% respectively. Stable outcomes with less than 5% change in mean facility score were observed for a medicine basket down to 12 medicines. For smaller baskets, scores increased more rapidly with a widening range. CONCLUSION: This study has confirmed that the proposed adaptations to make SDG indicator 3.b.3 appropriate for children are robust, indicating that they could be an important addition to the official Global Indicator Framework. At least 12 child-appropriate medicines should be surveyed to obtain meaningful outcomes. General concerns that remain about the weighting of medicines for DB and the NPL should be considered at the 2025 planned review of this framework
Chronic non-specific abdominal complaints in general practice: a prospective study on management, patient health status and course of complaints
BACKGROUND: While in general practice chronic non-specific abdominal complaints are common, there is insufficient data on the clinical course and the management of these complaints. Aim of this study was to present a primary care based profile of these chronic complaints including health care involvement, health status and clinical course. METHODS: Thirty general practitioners (GPs) and patients from their practices participated in a prospective follow-up study. All patients and GPs were asked to complete questionnaires at baseline and at 6, 12 and 18 months of follow-up. The GPs provided information on diagnostic and therapeutic management and on referral concerning 619 patients with chronic non-specific abdominal complaints, while 291 patients provided information about health status and clinical course of the complaints. RESULTS: When asked after 18 months of follow-up, 51,7% of the patients reported an equal or worsened severity of complaints. General health perception was impaired and patients had high scores on SCL-anxiety and SCL-depression scales. Diagnostic tests other than physical examination and laboratory tests were not frequently used. Medication was the most frequent type of treatment. The persistence of chronic non-specific abdominal complaints was quite stable. CONCLUSION: Once non-specific chronic abdominal complaints have become labelled as chronic by the attending physician, little improvement can be expected. The impact on patients' physiological and psychological well-being is large. GPs use a variety of diagnostic and therapeutic strategies. Research into the evidence base of currently applied management strategies is recommended
High-yield identification of pathogenic NF1 variants by skin fibroblast transcriptome screening after apparently normal diagnostic DNA testing
Neurofibromatosis type 1 (NF1) is caused by inactivating mutations in NF1. Due to the size, complexity, and high mutation rate at the NF1 locus, the identification of causative variants can be challenging. To obtain a molecular diagnosis in 15 individuals meeting diagnostic criteria for NF1, we performed transcriptome analysis (RNA-seq) on RNA obtained from cultured skin fibroblasts. In each case, routine molecular DNA diagnostics had failed to identify a disease-causing variant in NF1. A pathogenic variant or abnormal mRNA splicing was identified in 13 cases: 6 deep intronic variants and 2 transposon insertions causing noncanonical splicing, 3 postzygotic changes, 1 branch point mutation and, in 1 case, abnormal splicing for which the responsible DNA change remains to be identified. These findings helped resolve the molecular findings for an additional 17 individuals in multiple families with NF1, demonstrating the utility of skin-fibroblast-based transcriptome analysis for molecular diagnostics. RNA-seq improves mutation detection in NF1 and provides a powerful complementary approach to DNA-based methods. Importantly, our approach is applicable to other genetic disorders, particularly those caused by a wide variety of variants in a limited number of genes and specifically for individuals in whom routine molecular DNA diagnostics did not identify the causative variant.</p
Famine food of vegetal origin consumed in the Netherlands during World War II
Background: Periods of extreme food shortages during war force people to eat food that they normally do not consider edible. The last time that countries in Western Europe experienced severe scarcities was during World War II. The so-called Dutch famine or Hunger Winter (1944-1945) made at least 25,000 victims. The Dutch government took action by opening soup kitchens and providing information on wild plants and other famine food sources in "wartime cookbooks." The Dutch wartime diet has never been examined from an ethnobotanical perspective. Methods: We interviewed 78 elderly Dutch citizens to verify what they remembered of the consumption of vegetal and fungal famine food during World War II by them and their close surroundings. We asked whether they experienced any adverse effects from consuming famine food plants and how they knew they were edible. We identified plant species mentioned during interviews by their local Dutch names and illustrated field guides and floras. We hypothesized that people living in rural areas consumed more wild species than urban people. A Welch t test was performed to verify whether the number of wild and cultivated species differed between urban and rural citizens. Results: A total number of 38 emergency food species (14 cultivated and 21 wild plants, three wild fungi) were mentioned during interviews. Sugar beets, tulip bulbs, and potato peels were most frequently consumed. Regularly eaten wild species were common nettle, blackberry, and beechnuts. Almost one third of our interviewees explicitly described to have experienced extreme hunger during the war. People from rural areas listed significantly more wild species than urban people. The number of cultivated species consumed by both groups was similar. Negative effects were limited to sore throats and stomachache from the consumption of sugar beets and tulip bulbs. Knowledge on the edibility of famine food was obtained largely by oral transmission; few people remembered the written recipes in wartime cookbooks. Conclusion: This research shows that 71years after the Second World War, knowledge on famine food species, once crucial for people's survival, is still present in the Dutch society. The information on famine food sources supplied by several institutions was not distributed widely. For the necessary revival of famine food knowledge during the 1940s, people needed to consult a small group of elders. Presumed toxicity was a major reason given by our participants to explain why they did not collect wild plants or mushrooms during the war
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