744 research outputs found
Posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws
Purpose: C1-C2 instability or painful osteoarthritis are recognised indications for posterior atlanto-axial fixation. In the traditional trans-articular C1-C2 screw fixation, up to 20% of patients cannot have safe placement of bilateral screws in the event of a medially located vertebral artery and a straight screw trajectory in the sagittal plane. The more recently developed C1-C2 fixation technique with individual C1 lateral mass screws and converging C2 pars screws can be employed in case of a medially located vertebral artery and has comparable biomechanical strength. This is a prospective observational study to investigate the advantages, the safety, and the drawbacks of posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws. Methods: Twelve consecutive patients with C1-2 instability (n = 11) and painful osteoarthritis (n = 1) underwent a posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws. The average follow-up was 16months and all patients reached the 12-month follow-up. Findings: No hardware failure occurred in any of the patients. Correct screw placement and construct stability was found in all 12 patients (100%) at 6 and 12months after surgery. Mean neck pain on a visual analogue scale (VAS) was 2.1 at 6months and 2.0 at 12months. Only transient complications were observed: one patient presented with progressive intestinal herniation through the iliac crest scar; one suffered from severe pain at the posterior iliac crest for 3 months and three patients complained of annoying pain/dysaesthesia in the C2 dermatome for 3-6months after surgery. Conclusion: This study confirms that posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws is a safe and effective surgical option in the treatment of atlanto-axial instability or painful osteoarthriti
Evaluation of parasitism and predation of Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) by Diglyphus isaea (Walker, 1838) (Hymenoptera: Eulophidae)
To evaluate an eventual parasitism and/or predation behaviour of the eulophid parasitoid Diglyphus isaea
(Walker, 1838) on Tuta absoluta (Meyrick, 1917) larvae two assays were performed releasing adult parasitoids. The
first assay was conducted in Petri dishes using tomato leaflets havig mines with T. absoluta larvae inside. The
second, was performed on previously infested potted tomato plants. In both assays no parasitism but only predation
was found. Predation was observed, mainly on L2 and L3 larvae which had moulted. Proportion of clearly preyed
larvae reached 17% in Petri dishes and 38% in potted plants. Predation was attested by the presence of punctures
done by the oviscapt of the female parasitoid. A significant higher proportion of dead larvae where it was not
possible to see punctures occurred in the presence of the parasitoid females. Some of them probably were also
preyed on by D. isaea femalesinfo:eu-repo/semantics/publishedVersio
Relationship of Alexithymia Ratings to Dopamine D2-type Receptors in Anterior Cingulate and Insula of Healthy Control Subjects but Not Methamphetamine-Dependent Individuals.
BackgroundIndividuals with substance-use disorders exhibit emotional problems, including deficits in emotion recognition and processing, and this class of disorders also has been linked to deficits in dopaminergic markers in the brain. Because associations between these phenomena have not been explored, we compared a group of recently abstinent methamphetamine-dependent individuals (n=23) with a healthy-control group (n=17) on dopamine D2-type receptor availability, measured using positron emission tomography with [(18)F]fallypride.MethodsThe anterior cingulate and anterior insular cortices were selected as the brain regions of interest, because they receive dopaminergic innervation and are thought to be involved in emotion awareness and processing. The Toronto Alexithymia Scale, which includes items that assess difficulty in identifying and describing feelings as well as externally oriented thinking, was administered, and the scores were tested for association with D2-type receptor availability.ResultsRelative to controls, methamphetamine-dependent individuals showed higher alexithymia scores, reporting difficulty in identifying feelings. The groups did not differ in D2-type receptor availability in the anterior cingulate or anterior insular cortices, but a significant interaction between group and D2-type receptor availability in both regions, on self-report score, reflected significant positive correlations in the control group (higher receptor availability linked to higher alexithymia) but nonsignificant, negative correlations (lower receptor availability linked to higher alexithymia) in methamphetamine-dependent subjects.ConclusionsThe results suggest that neurotransmission through D2-type receptors in the anterior cingulate and anterior insular cortices influences capacity of emotion processing in healthy people but that this association is absent in individuals with methamphetamine dependence
A Fine-Grain Error Map Prediction and Segmentation Quality Assessment Framework for Whole-Heart Segmentation
When introducing advanced image computing algorithms, e.g., whole-heart
segmentation, into clinical practice, a common suspicion is how reliable the
automatically computed results are. In fact, it is important to find out the
failure cases and identify the misclassified pixels so that they can be
excluded or corrected for the subsequent analysis or diagnosis. However, it is
not a trivial problem to predict the errors in a segmentation mask when ground
truth (usually annotated by experts) is absent. In this work, we attempt to
address the pixel-wise error map prediction problem and the per-case mask
quality assessment problem using a unified deep learning (DL) framework.
Specifically, we first formalize an error map prediction problem, then we
convert it to a segmentation problem and build a DL network to tackle it. We
also derive a quality indicator (QI) from a predicted error map to measure the
overall quality of a segmentation mask. To evaluate the proposed framework, we
perform extensive experiments on a public whole-heart segmentation dataset,
i.e., MICCAI 2017 MMWHS. By 5-fold cross validation, we obtain an overall Dice
score of 0.626 for the error map prediction task, and observe a high Pearson
correlation coefficient (PCC) of 0.972 between QI and the actual segmentation
accuracy (Acc), as well as a low mean absolute error (MAE) of 0.0048 between
them, which evidences the efficacy of our method in both error map prediction
and quality assessment.Comment: 9 pages, accepted by MICCAI'1
High-pressure transport properties of CeRu_2Ge_2
The pressure-induced changes in the temperature-dependent thermopower S(T)
and electrical resistivity \rho(T) of CeRu_2Ge_2 are described within the
single-site Anderson model. The Ce-ions are treated as impurities and the
coherent scattering on different Ce-sites is neglected. Changing the
hybridisation \Gamma between the 4f-states and the conduction band accounts for
the pressure effect. The transport coefficients are calculated in the
non-crossing approximation above the phase boundary line. The theoretical S(T)
and \rho(T) curves show many features of the experimental data. The seemingly
complicated temperature dependence of S(T) and \rho(T), and their evolution as
a function of pressure, is related to the crossovers between various fixed
points of the model.Comment: 9 pages, 10 figure
The osteoporosis treatment gap in patients at risk of fracture in European primary care : a multi-country cross-sectional observational study
Summary
This study in 8 countries across Europe found that about 75% of elderly women seen in primary care who were at high risk of osteoporosis-related fractures were not receiving appropriate medication. Lack of osteoporosis diagnosis appeared to be an important contributing factor.
Introduction
Treatment rates in osteoporosis are documented to be low. We wished to assess the osteoporosis treatment gap in women ≥ 70 years in routine primary care across Europe.
Methods
This cross-sectional observational study in 8 European countries collected data from women 70 years or older visiting their general practitioner. The primary outcome was treatment gap: the proportion who were not receiving any osteoporosis medication among those at increased risk of fragility fracture (using history of fracture, 10-year probability of fracture above country-specific Fracture Risk Assessment Tool [FRAX] thresholds, T-score ≤ − 2.5).
Results
Median 10-year probability of fracture (without bone mineral density [BMD]) for the 3798 enrolled patients was 7.2% (hip) and 16.6% (major osteoporotic). Overall, 2077 women (55%) met one or more definitions for increased risk of fragility fracture: 1200 had a prior fracture, 1814 exceeded the FRAX threshold, and 318 had a T-score ≤ − 2.5 (only 944 received a dual-energy x-ray absorptiometry [DXA] scan). In those at increased fracture risk, the median 10-year probability of hip and major osteoporotic fracture was 11.2% and 22.8%, vs 4.1% and 11.5% in those deemed not at risk. An osteoporosis diagnosis was recorded in 804 patients (21.2%); most (79.7%) of these were at increased fracture risk. The treatment gap was 74.6%, varying from 53% in Ireland to 91% in Germany. Patients with an osteoporosis diagnosis were found to have a lower treatment gap than those without a diagnosis, with an absolute reduction of 63%.
Conclusions
There is a large treatment gap in women aged ≥ 70 years at increased risk of fragility fracture in routine primary care across Europe. The gap appears to be related to a low rate of osteoporosis diagnosis
Probing the phase diagram of CeRu_2Ge_2 by thermopower at high pressure
The temperature dependence of the thermoelectric power, S(T), and the
electrical resistivity of the magnetically ordered CeRu_2Ge_2 (T_N=8.55 K and
T_C=7.40 K) were measured for pressures p < 16 GPa in the temperature range 1.2
K < T < 300 K. Long-range magnetic order is suppressed at a p_c of
approximately 6.4 GPa. Pressure drives S(T) through a sequence of temperature
dependences, ranging from a behaviour characteristic for magnetically ordered
heavy fermion compounds to a typical behaviour of intermediate-valent systems.
At intermediate pressures a large positive maximum develops above 10 K in S(T).
Its origin is attributed to the Kondo effect and its position is assumed to
reflect the Kondo temperature T_K. The pressure dependence of T_K is discussed
in a revised and extended (T,p) phase diagram of CeRu_2Ge_2.Comment: 7 pages, 6 figure
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Present and future nitrogen deposition to national parks in the United States: critical load exceedances
National parks in the United States are protected areas wherein the natural habitat is to be conserved for future generations. Deposition of anthropogenic nitrogen (N) transported from areas of human activity (fuel combustion, agriculture) may affect these natural habitats if it exceeds an ecosystem-dependent critical load (CL). We quantify and interpret the deposition to Class I US national parks for present-day and future (2050) conditions using the GEOS-Chem global chemical transport model with 1/2° × 2/3° horizontal resolution over North America. We estimate CL values in the range 2.5–5 kg N ha−1 yr−1 for the different parks to protect the most sensitive ecosystem receptors. For present-day conditions, we find 24 out of 45 parks to be in CL exceedance and 14 more to be marginally so. Many of these are in remote areas of the West. Most (40–85%) of the deposition originates from NOx emissions (fuel combustion). We project future changes in N deposition using representative concentration pathway (RCP) anthropogenic emission scenarios for 2050. These feature 52–73% declines in US NOx emissions relative to present but 19–50% increases in US ammonia (NH3) emissions. Nitrogen deposition at US national parks then becomes dominated by domestic NH3 emissions. While deposition decreases in the East relative to present, there is little progress in the West and increases in some regions. We find that 17–25 US national parks will have CL exceedances in 2050 based on the RCP8.5 and RCP2.6 scenarios. Even in total absence of anthropogenic NOx emissions, 14–18 parks would still have a CL exceedance. Returning all parks to N deposition below CL by 2050 would require at least a 50% decrease in US anthropogenic NH3 emissions relative to RCP-projected 2050 levels.Engineering and Applied Science
Improving Lesion Segmentation for Diabetic Retinopathy using Adversarial Learning
Diabetic Retinopathy (DR) is a leading cause of blindness in working age
adults. DR lesions can be challenging to identify in fundus images, and
automatic DR detection systems can offer strong clinical value. Of the publicly
available labeled datasets for DR, the Indian Diabetic Retinopathy Image
Dataset (IDRiD) presents retinal fundus images with pixel-level annotations of
four distinct lesions: microaneurysms, hemorrhages, soft exudates and hard
exudates. We utilize the HEDNet edge detector to solve a semantic segmentation
task on this dataset, and then propose an end-to-end system for pixel-level
segmentation of DR lesions by incorporating HEDNet into a Conditional
Generative Adversarial Network (cGAN). We design a loss function that adds
adversarial loss to segmentation loss. Our experiments show that the addition
of the adversarial loss improves the lesion segmentation performance over the
baseline.Comment: Accepted to International Conference on Image Analysis and
Recognition, ICIAR 2019. Published at
https://doi.org/10.1007/978-3-030-27272-2_29 Code:
https://github.com/zoujx96/DR-segmentatio
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