548 research outputs found
Shape from Projections via Differentiable Forward Projector for Computed Tomography
In computed tomography, the reconstruction is typically obtained on a voxel
grid. In this work, however, we propose a mesh-based reconstruction method. For
tomographic problems, 3D meshes have mostly been studied to simulate data
acquisition, but not for reconstruction, for which a 3D mesh means the inverse
process of estimating shapes from projections. In this paper, we propose a
differentiable forward model for 3D meshes that bridge the gap between the
forward model for 3D surfaces and optimization. We view the forward projection
as a rendering process, and make it differentiable by extending recent work in
differentiable rendering. We use the proposed forward model to reconstruct 3D
shapes directly from projections. Experimental results for single-object
problems show that the proposed method outperforms traditional voxel-based
methods on noisy simulated data. We also apply the proposed method on electron
tomography images of nanoparticles to demonstrate the applicability of the
method on real data
Screening for left ventricular hypertrophy in patients with type 2 diabetes mellitus in the community
<p>Abstract</p> <p>Background</p> <p>Left ventricular hypertrophy (LVH) is a strong predictor of cardiovascular disease and is common among patients with type 2 diabetes. However, no systematic screening for LVH is currently recommended for patients with type 2 diabetes. The purpose of this study was to determine whether NT-proBNP was superior to 12-lead electrocardiography (ECG) for detection of LVH in patients with type 2 diabetes.</p> <p>Methods</p> <p>Prospective cross-sectional study comparing diagnostic accuracy of ECG and NT-proBNP for the detection of LVH among patients with type 2 diabetes. Inclusion criteria included having been diagnosed for > 5 years and/or on treatment for type 2 diabetes; patients with Stage 3/4 chronic kidney disease and known cardiovascular disease were excluded. ECG LVH was defined as either the Sokolow-Lyon or Cornell voltage criteria. NT-proBNP level was measured using the Roche Diagnostics Elecsys assay. Left ventricular mass was assessed from echocardiography. Receiver operating characteristic curve analysis was carried out and area under the curve (AUC) was calculated.</p> <p>Results</p> <p>294 patients with type 2 diabetes were recruited, mean age 58 (SD 11) years, BP 134/81 ± 18/11 mmHg, HbA<sub>1c </sub>7.3 ± 1.5%. LVH was present in 164 patients (56%). In a logistic regression model age, gender, BMI and a history of hypertension were important determinants of LVH (p < 0.05). Only 5 patients with LVH were detected by either ECG voltage criteria. The AUC for NT-proBNP in detecting LVH was 0.68.</p> <p>Conclusions</p> <p>LVH was highly prevalent in asymptomatic patients with type 2 diabetes. ECG was an inadequate test to identify LVH and while NT-proBNP was superior to ECG it remained unsuitable for detecting LVH. Thus, there remains a need for a screening tool to detect LVH in primary care patients with type 2 diabetes to enhance risk stratification and management.</p
High probability of comorbidities in bronchial asthma in Germany
Clinical experience has shown that allergic and non-allergic respiratory, metabolic, mental, and cardiovascular disorders sometimes
coexist with bronchial asthma. However, no study has been carried out that calculates the chance of manifestation of these
disorders with bronchial asthma in Saarland and Rhineland-Palatinate, Germany. Using ICD10 diagnoses from health care
institutions, the present study systematically analyzed the co-prevalence and odds ratios of comorbidities in the asthma population
in Germany. The odds ratios were adjusted for age and sex for all comorbidities for patients with asthma vs. without asthma.
Bronchial asthma was strongly associated with allergic and with a lesser extent to non-allergic comorbidities: OR 7.02 (95%
CI:6.83–7.22) for allergic rhinitis; OR 4.98 (95%CI:4.67–5.32) allergic conjunctivitis; OR 2.41 (95%CI:2.33–2.52) atopic dermatitis; OR
2.47 (95%CI:2.16–2.82) food allergy, and OR 1.69 (95%CI:1.61–1.78) drug allergy. Interestingly, increased ORs were found for
respiratory diseases: 2.06 (95%CI:1.64–2.58) vocal dysfunction; 1.83 (95%CI:1.74–1.92) pneumonia; 1.78 (95%CI:1.73–1.84) sinusitis;
1.71 (95%CI:1.65–1.78) rhinopharyngitis; 2.55 (95%CI:2.03–3.19) obstructive sleep apnea; 1.42 (95%CI:1.25–1.61) pulmonary
embolism, and 3.75 (95%CI:1.64–8.53) bronchopulmonary aspergillosis. Asthmatics also suffer from psychiatric, metabolic, cardiac
or other comorbidities. Myocardial infarction (OR 0.86, 95%CI:0.79–0.94) did not coexist with asthma. Based on the calculated
chances of manifestation for these comorbidities, especially allergic and respiratory, to a lesser extent also metabolic,
cardiovascular, and mental disorders should be taken into consideration in the diagnostic and treatment strategy of bronchial
asthma
Associations of oxygenated hemoglobin with disease burden and prognosis in stable COPD: Results from COSYCONET
We studied whether in patients with stable COPD blood gases (BG), especially oxygenated hemoglobin (OxyHem) as a novel biomarker confer information on disease burden and prognosis and how this adds to the information provided by the comorbidity pattern and systemic inflammation. Data from 2137 patients (GOLD grades 1-4) of the baseline dataset of the COSYCONET COPD cohort were used. The associations with dyspnea, exacerbation history, BODE-Index (cut-off 8000/mu L was 2.33 (95% CI: 1.60-3.39, p<0.0001). In stable COPD, the concentration of oxygenated hemoglobin provided additional information on disease state, especially mortality risk. OxyHem can be calculated from hemoglobin concentration and oxygen saturation without the need for the measurement of PaO2. It thus appears well suited for clinical use with minimal equipment, especially for GPs
Measuring Lattice Strain in Three Dimensions through Electron Microscopy
The three-dimensional (3D) atomic structure of nanomaterials, including strain, is crucial to understand their properties. Here, we investigate lattice strain in Au nanodecahedra using electron tomography. Although different electron tomography techniques enabled 3D characterizations of nanostructures at the atomic level, a reliable determination of lattice strain is not straightforward. We therefore propose a novel model-based approach from which atomic coordinates are
Associations of oxygenated hemoglobin with disease burden and prognosis in stable COPD : Results from COSYCONET
We studied whether in patients with stable COPD blood gases (BG), especially oxygenated hemoglobin (OxyHem) as a novel biomarker confer information on disease burden and prognosis and how this adds to the information provided by the comorbidity pattern and systemic inflammation. Data from 2137 patients (GOLD grades 1–4) of the baseline dataset of the COSYCONET COPD cohort were used. The associations with dyspnea, exacerbation history, BODE-Index (cut-off ≤2) and all-cause mortality over 3 years of follow-up were determined by logistic and Cox regression analyses, with sex, age, BMI and pack years as covariates. Predictive values were evaluated by ROC curves. Capillary blood gases included SaO2, PaO2, PaCO2, pH, BE and the concentration of OxyHem [haemoglobin (Hb) x fractional SaO2, g/dL] as a simple-to-measure correlate of oxygen content. Inflammatory markers were WBC, CRP, IL-6 and -8, TNF-alpha and fibrinogen, and comorbidities comprised a broad panel including cardiac and metabolic disorders. Among BG, OxyHem was associated with dyspnoea, exacerbation history, BODE-Index and mortality. Among inflammatory markers and comorbidities, only WBC and heart failure were consistently related to all outcomes. ROC analyses indicated that OxyHem provided information of a magnitude comparable to that of WBC, with optimal cut-off values of 12.5 g/dL and 8000/µL, respectively. Regarding mortality, OxyHem also carried independent, additional information, showing a hazard ratio of 2.77 (95% CI: 1.85–4.15, p  8000/µL was 2.33 (95% CI: 1.60–3.39, p < 0.0001). In stable COPD, the concentration of oxygenated hemoglobin provided additional information on disease state, especially mortality risk. OxyHem can be calculated from hemoglobin concentration and oxygen saturation without the need for the measurement of PaO2. It thus appears well suited for clinical use with minimal equipment, especially for GPs
Dutch and German 3-year-olds’ representations of voicing alternations
The voicing contrast is neutralised syllable and word finally in Dutch and German, leading to alternations within the morphological paradigm (e.g. Dutch ‘bed(s)’, be[t] be[d]en, German ‘dog(s)’, Hun[t]-Hun[d]e). Despite structural similarity, language-specific morphological, phonological and lexical properties impact on the distribution of this alternation in the two languages. Previous acquisition research has focused on one language only, predominantly focusing on children’s production accuracy, concluding that alternations are not acquired until late in the acquisition process in either language. This paper adapts a perceptual method to investigate how voicing alternations are represented in the mental lexicon of Dutch and German 3-year-olds. Sensitivity to mispronunciations of voicing word-medially in plural forms was measured using a visual fixation procedure. Dutch children exhibited evidence of overgeneralising the voicing alternation, whereas German children consistently preferred the correct pronunciation to mispronunciations. Results indicate that the acquisition of voicing alternations is influenced by language-specific factors beyond the alternation itself
Epithelial antimicrobial peptides in host defense against infection
One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation
The impact of COPD on polyneuropathy : results from the German COPD cohort COSYCONET
Background: Peripheral neuropathy is a common comorbidity in COPD. We aimed to investigate associations
between alterations commonly found in COPD and peripheral neuropathy, with particular emphasize on the
distinction between direct and indirect effects.
Methods: We used visit 4 data of the COPD cohort COSYCONET, which included indicators of polyneuropathy
(repeated tuning fork and monofilament testing), excluding patients with diabetes a/o increased HbA1c. These
indicators were analysed for the association with COPD characteristics, including lung function, blood gases, 6-min
walk distance (6-MWD), timed-up-and-go-test (TUG), exacerbation risk according to GOLD, C-reactive protein (CRP),
and ankle-brachial index (ABI). Based on the results of conventional regression analyses adjusted for age, BMI,
packyears and gender, we utilized structural equation modelling (SEM) to quantify the network of direct and
indirect relationships between parameters.
Results: 606 patients were eligible for analysis. The indices of polyneuropathy were highly correlated with each
other and related to base excess (BE), ABI and TUG. ABI was linked to neuropathy and 6-MWD, exacerbations
depended on FEV1, 6-MWD and CRP. The associations could be summarized into a SEM comprising polyneuropathy
as a latent variable (PNP) with three measured indicator variables. Importantly, PNP was directly dependent on ABI
and particularly on BE. When also including patients with diabetes and/or elevated values of HbA1c (n = 742) the
SEM remained virtually the same.
Conclusion: We identified BE and ABI as major determinants of peripheral neuropathy in patients with COPD. All
other associations, particularly those with lung function and physical capacity, were indirect. These findings
underline the importance of alterations of the micromilieu in COPD, in particular the degree of metabolic
compensation and vascular status
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Search for intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network
Gravitational-wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar-mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational-wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event is detected in this search. Consequently, we place upper limits on the merger rate density for a family of intermediate mass black hole binaries. In particular, we choose sources with total masses M=m1+m2ϵ[120,800] M and mass ratios q=m2/m1ϵ[0.1,1.0]. For the first time, this calculation is done using numerical relativity waveforms (which include higher modes) as models of the real emitted signal. We place a most stringent upper limit of 0.20 Gpc-3 yr-1 (in comoving units at the 90% confidence level) for equal-mass binaries with individual masses m1,2=100 M and dimensionless spins χ1,2=0.8 aligned with the orbital angular momentum of the binary. This improves by a factor of ∼5 that reported after Advanced LIGO's first observing run
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