The urgency for energy transition from non-renewable to renewable sources has highlighted the importance of salt caverns for storing gases and disposing of nuclear wastes. While salt caverns are ...valuable for storage due to their low permeability and self-healing features, they present challenges, notably creep deformations in cavern walls leading to surface subsidence. Research in this field has predominantly focused on precisely determining the creep properties of rock salt through advanced laboratory tests and developing sophisticated constitutive models to simulate salt rock behavior numerically. However, the properties of the overburden rocks are often overlooked, with their numerical modeling typically relying on simpler constitutive models, such as the isotropic linear-elastic model, or being represented merely as a uniform surcharge equivalent to the weight of the overburden rock at the top of the rock salt deposit. Nonetheless, the arching of stresses above salt cavern fields is heavily influenced by the properties of the overburden rocks, indicating that these properties are probably influential on the geomechanical behavior of salt cavern fields. To date, research on the influence of overburden rock properties on the geomechanical behavior of salt cavern fields remains unexplored. This technical note aims to shed light on this issue by examining the impact of overburden rock properties on stress redistribution and surface subsidence above a hypothetical cavern field. A 3D Finite Element Method model simulating the creep process for a field of 36 caverns within a rock salt deposit was developed. The findings reveal that the stiffness of the rock mass significantly influences the arching of stresses above this hypothetical cavern field. The more competent the overburden rock mass, the greater the stress relief in the mining area, and the wider the unmined area receiving the redistributed stresses. Thus, the differential stresses within the rock salt deposit in the mined region are reduced as the overburden rock mass becomes stiffer and stronger. Since creep deformations heavily depend on differential stresses, the properties of the overburden rock mass significantly influenced both the rate of cavern convergence and the rate of surface subsidence of the hypothetical cavern field over time. The results presented in this technical note highlight the potentially crucial role of overburden rock properties in the geomechanical behavior of cavern fields and suggest that future research should carefully consider the behavior of overburden rocks in numerical models of cavern fields.
Promoting four healthy behaviours among preschool children:⩾4 servings of fruit and vegetables/day, ⩾2 h/day of active play, ⩽1 h per day of TV-watching and 0 sugar sweetened beverages/day.
We ...conducted a c-RCT on 425 3-year-old children at 16 childcare centres based in Cesena, Italy. We randomly allocated eight childcare centres (199 children) to the intervention group and eight childcare centres (226 children) to the control group. All the randomized childcare centres completed our study protocol. Parents recorded their children's target behaviours at home over 3 Saturdays, at baseline and at follow-up. Then trained nurses measured children's weight and height. We conducted a 6-month-long intervention trial in local health care centres where nurses and primary care pediatricians, respectively, conducted two subsequent motivational interviews with parents to encourage children's healthy behaviours at home. At the same time, teachers involved children in learning experiences about healthy behaviours. Our primary outcome is a children's combined health behaviour score (CHBS) at home. Our secondary outcomes measure the BMI z-score and the percentage of children that show a BMI trajectory crossing upward. After collecting the CHBS and BMI data at baseline as well as at 1- and 2-year follow-ups, we performed an Intent-to-Treat (ITT) analysis.
After 2 years from baseline, 48.4% of intervention group children showed a low-risk CHBS in comparison with 28.0% of control group children. A multilevel analysis showed that they were by far more likely to achieve low-risk scores (adjusted OR: 3.41; 95% CI: 1.48-7.88; P=0.004). Our BMI outcomes showed no significant difference between groups.
A multidimensional educational intervention, which consists of motivational interviews with parents and teacher-led learning experiences for children, improved preschool children's CHBS in the long term without influencing the outcomes of BMI z-score and BMI increase.
Purpose
To assess current clinical practices throughout Europe with respect to acquisition, implementation, evaluation, and interpretation of language functional MRI (fMRI) in epilepsy patients.
...Methods
An online survey was emailed to all European Society of Neuroradiology members (
n
= 1662), known associates (
n
= 6400), and 64 members of European Epilepsy network. The questionnaire featured 40 individual items on demographic data, clinical practice and indications, fMRI paradigms, radiological workflow, data post-processing protocol, and reporting.
Results
A total of 49 non-duplicate entries from European centers were received from 20 countries. Of these, 73.5% were board-certified neuroradiologists and 69.4% had an in-house epilepsy surgery program. Seventy-one percent of centers performed fewer than five scans per month for epilepsy. The most frequently used paradigms were phonemic verbal fluency (47.7%) and auditory comprehension (55.6%), but variants of 13 paradigms were described. Most centers assessed the fMRI task performance (75.5%), ensured cognitive-task adjustment (77.6%), trained the patient before scanning (85.7%), and assessed handedness (77.6%), but only 28.6% had special paradigms for patients with cognitive impairments. fMRI was post-processed mainly by neuroradiologists (42.1%), using open-source software (55.0%). Reporting was done primarily by neuroradiologists (74.2%). Interpretation was done mainly by visual inspection (65.3%). Most specialists (81.6%) were able to determine the hemisphere dominance for language in more than 75% of exams, attributing failure to the patient not performing the task correctly.
Conclusion
This survey shows that language fMRI is firmly embedded in the preoperative management of epilepsy patients. The wide variety of paradigms and the use of non-CE-marked software underline the need for establishing reference standards.
Innovative luminescent nanomaterials, termed upconversion nanoparticles (UCNPs), have demonstrated considerable promise as molecular probes for high-contrast optical imaging in cells and small ...animals. The feasibility study of optical diagnostics in humans is reported here based on experimental and theoretical modeling of optical imaging of an UCNP-labeled breast cancer lesion. UCNPs synthesized in-house were surface-capped with an amphiphilic polymer to achieve good colloidal stability in aqueous buffer solutions. The scFv4D5 mini-antibodies were grafted onto the UCNPs via a high-affinity molecular linker barstar:barnase (Bs:Bn) to allow their specific binding to the human epidermal growth factor receptor HER2/neu, which is overexpressed in human breast adenocarcinoma cells SK-BR-3. UCNP-Bs:Bn-scFv4D5 biocomplexes exhibited high-specific immobilization on the SK-BR-3 cells with the optical contrast as high as 10:1 benchmarked against a negative control cell line. Breast cancer optical diagnostics was experimentally modeled by means of epi-luminescence imaging of a monolayer of the UCNP-labeled SK-BR-3 cells buried under a breast tissue mimicking optical phantom. The experimental results were analyzed theoretically and projected to in vivo detection of early-stage breast cancer. The model predicts that the UCNP-assisted cancer detection is feasible up to 4 mm in tissue depth, showing considerable potential for diagnostic and image-guided surgery applications.
In patients with temporal lobe epilepsy (TLE), assessment of language lateralization is important as anterior temporal lobectomy may lead to language impairments. Despite the widespread use of fMRI, ...evidence of its usefulness in predicting postsurgical language performance is scant. We investigated whether preoperative functional lateralization is related to the preoperative language performance, peri-ictal aphasia, and can predict language outcome one year post-surgery. We studied a total of 72 TLE patients (42 left, 30 right), by using three fMRI tasks: Naming, Verb Generation and Fluency. Functional lateralization indices were analyzed with neuropsychological scores and presence of peri-ictal aphasia. The key findings are:1)Both left and right TLE patients show decreased left lateralization compared to controls.2)Lateralization correlates with language performance before surgery. In left TLE, decreased left lateralization correlates with better fluency performance. In right TLE, increased left lateralization during the Naming task correlates with better naming.3)Left lateralization correlates with peri-ictal aphasia in left TLE patients.4)Lateralization correlates with language performance after surgery. In a subgroup of left TLE who underwent surgery (17 left), decreased left lateralization is predictive of better naming performance at 6 and 12 months after surgery. The present study highlights the clinical relevance of fMRI language lateralization in TLE, especially to predict language outcome one year post-surgery. We also underline the importance of using fMRI tasks eliciting frontal and anterior temporal activations, when studying left and right TLE patients.
Buoyancy effect on shallow tunnels Vitali, Osvaldo P.M.; Celestino, Tarcisio B.; Bobet, Antonio
International journal of rock mechanics and mining sciences (Oxford, England : 1997),
February 2019, 2019-02-00, 20190201, Letnik:
114
Journal Article
Recenzirano
When a shallow tunnel is excavated, an overall upward movement appears as a result of the weight removal from the excavation. This movement is analogous to buoyancy. When numerical simulation of ...shallow tunnels is used, the magnitude of the upward movement increases with the depth of the lower boundary, defined as the distance from the tunnel center to the bottom of the mesh. This seems counterintuitive, and yet it is mathematically correct. This paper investigates the influence of the assumptions made to model the buoyancy phenomenon numerically, and specifically the (typical) plane strain and elasticity assumptions. Three-dimensional and two-dimensional plane strain numerical models are carried out using a linear elastic model, where the influence of the ground stiffness increasing with depth is assessed. The results show that the buoyancy effect, i.e. increasing upwards movements with depth of the lower boundary, decreases when the ground stiffness increases with depth.
Summary Background Microbial air monitoring in operating theatres has been a subject of interest and debate. No generally accepted sampling methods and threshold values are available. Aim To assess ...microbial air contamination in empty and working conventionally ventilated operating theatres over a three-year period at the University Hospital of Parma, Italy. Methods Air sampling was performed in 29 operating theatres. Both active and passive sampling methods were used to assess bacterial and fungal contamination. Findings In empty theatres, median bacterial values of 12 colony-forming units (cfu)/m3 interquartile range (IQR) 4–32 and 1 index of microbial air contamination (IMA) (IQR 0–3) were recorded. In working theatres, these values increased significantly ( P < 0.001) to 80 cfu/m3 (IQR 42–176) and 7 IMA (IQR 4–13). Maximum recorded values were 166 cfu/m3 and 8 IMA for empty theatres, and 798 cfu/m3 and 42 IMA for working theatres. Combining active and passive samplings, fungi were isolated in 39.13% of samples collected in empty theatres and 56.95% of samples collected in working theatres. Over the three-year study period, bacterial contamination decreased in both empty and working theatres, and the percentage of samples devoid of fungi increased. In working theatres, a significant correlation was found between the bacterial contamination values assessed using passive and active sampling methods ( P < 0.001). Conclusion Microbiological monitoring is a useful tool for assessment of the contamination of operating theatres in order to improve air quality.
Rock masses that have a well-defined structure may also present a remarked in situ stress anisotropy; thus, the misalignment of a tunnel with the geostatic principal stresses and/or with the ...principal axes of material anisotropy is very likely. Analytical solutions for tunnels in transversely anisotropic rock available in the literature assume alignment of the tunnel with the geostatic principal stresses and with one of the principal directions of the material anisotropy (i.e. 2D plane strain condition). Such assumption is quite restrictive. In this paper, a new analytical formulation for circular deep tunnels in fully anisotropic rock is presented. It provides the full stress and displacement fields around a tunnel misaligned with the geostatic principal stresses or with the directions of material anisotropy. The analytical solution has been verified by comparing its predictions with results from 3D FEM modelling, for a number of scenarios with increasing complexity. A parametric analysis has been conducted to investigate the interplay that exists between the orientation of the axis of the tunnel and the directions of the principal geostatic stresses and/or the directions of material anisotropy.
Diffusion Weighted Imaging is extremely important for the diagnosis of probable sporadic Jakob-Creutzfeldt disease, the most common human prion disease. Although visual assessment of DWI MRI is ...critical diagnostically, a more objective, quantifiable approach might more precisely identify the precise pattern of brain involvement. Furthermore, a quantitative, systematic tracking of MRI changes occurring over time might provide insights regarding the underlying histopathological mechanisms of human prion disease and provide information useful for clinical trials. The purposes of this study were: 1) to describe quantitatively the average cross-sectional pattern of reduced mean diffusivity, fractional anisotropy, atrophy and T1 relaxation in the gray matter (GM) in sporadic Jakob-Creutzfeldt disease, 2) to study changes in mean diffusivity and atrophy over time and 3) to explore their relationship with clinical scales. Twenty-six sporadic Jakob-Creutzfeldt disease and nine control subjects had MRIs on the same scanner; seven sCJD subjects had a second scan after approximately two months. Cortical and subcortical gray matter regions were parcellated with Freesurfer. Average cortical thickness (or subcortical volume), T1-relaxiation and mean diffusivity from co-registered diffusion maps were calculated in each region for each subject. Quantitatively on cross-sectional analysis, certain brain regions were preferentially affected by reduced mean diffusivity (parietal, temporal lobes, posterior cingulate, thalamus and deep nuclei), but with relative sparing of the frontal and occipital lobes. Serial imaging, surprisingly showed that mean diffusivity did not have a linear or unidirectional reduction over time, but tended to decrease initially and then reverse and increase towards normalization. Furthermore, there was a strong correlation between worsening of patient clinical function (based on modified Barthel score) and increasing mean diffusivity.
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