Autonomic function in amnestic and non-amnestic mild cognitive impairment : spectral heart rate variability analysis provides evidence for a brain–heart axis

Mild cognitive impairment (MCI) is a heterogeneous syndrome with two main clinical subtypes, amnestic (aMCI) and non-amnestic (naMCI). The analysis of heart rate variability (HRV) is a tool to assess autonomic function. Cognitive and autonomic processes are linked via the central autonomic network. Autonomic dysfunction entails several adverse outcomes. However, very few studies have investigated autonomic function in MCI and none have considered MCI subtypes or the relationship of HRV indices with different cognitive domains and structural brain damage. We assessed autonomic function during an active orthostatic challenge in 253 oupatients aged\u2009 65\u200965, [n\u2009=\u200982 aMCI, n\u2009=\u200993 naMCI, n\u2009=\u200978 cognitively normal (CN), neuropsychologically tested] with power spectral analysis of HRV. We used visual rating scales to grade cerebrovascular burden and hippocampal/insular atrophy (HA/IA) on neuroimaging. Only aMCI showed a blunted response to orthostasis. Postural changes in normalised low frequency (LF) power and in the LF to high frequency ratio correlated with a memory test (positively) and HA/IA (negatively) in aMCI, and with attention/executive function tests (negatively) and cerebrovascular burden (positively) in naMCI. These results substantiate the view that the ANS is differentially impaired in aMCI and naMCI, consistently with the neuroanatomic substrate of Alzheimer's and small-vessel subcortical ischaemic disease

Automatic speech analysis to early detect functional cognitive decline in elderly population

This study aimed at evaluating whether people with a normal cognitive function can be discriminated from subjects with a mild impairment of cognitive function based on a set of acoustic features derived from spontaneous speech. Voice recordings from 90 Italian subjects (age >65 years; group 1: 47 subjects with MMSE>26; group 2: 43 subjects with 20≤ MMSE ≤26) were collected. Voice samples were processed using a MATLAB-based custom software to derive a broad set of known acoustic features. Linear mixed model analyses were performed to select the features able to significantly distinguish between groups. The selected features (% of unvoiced segments, duration of unvoiced segments, % of voice breaks, speech rate, and duration of syllables), alone or in addition to age and years of education, were used to build a learning-based classifier. The leave-one-out cross validation was used for testing and the classifier accuracy was computed. When the voice features were used alone, an overall classification accuracy of 0.73 was achieved. When age and years of education were additionally used, the overall accuracy increased up to 0.80. These performances were lower than the accuracy of 0.86 found in a recent study. However, in that study the classification was based on several tasks, including more cognitive demanding tasks. Our results are encouraging because acoustic features, derived for the first time only from an ecologic continuous speech task, were able to discriminate people with a normal cognitive function from people with a mild cognitive decline. This study poses the basis for the development of a mobile application performing automatic voice analysis on-the-fly during phone calls, which might potentially support the detection of early signs of functional cognitive decline

Experimental Testing of Two Novel Stress Sensors for SHM of Masonry Structures

The paper presents an experimental study on the performance of two types of stress sensor for their possible use in structural health monitoring (SHM) of masonry constructions. Ceramic piezoelectric sensors and capacitive sensors were installed in mortar bed-joints of two series of masonry specimens made of calcarenite stones and clay bricks. The specimens were tested under uniaxial compression, assessing the effectiveness of the sensors in recording the stress state variation in terms of vertical stresses within different types of masonry. Experimental results show that, although both the ceramic and capacitive sensors were initially designed to be embedded in concrete elements, their application in mortar joints ensures a good agreement with records by standard measurement devices. Results also demonstrate the possibility to extend the application of these devices to existing masonry structures, where SHM becomes a challenging issue

Update on cervical disc arthroplasty: where are we and where are we going?

Despite the very good results of anterior cervical discectomy and fusion, there are concerns of adjacent level degeneration. For this reason, interest has grown in the potential for motion sparing alternatives. Cervical disc arthroplasty is thus evolving as a potential alternative to fusion. Specific design characteristic and implants will be reviewed and outcomes summarized

Regional differences in prostaglandin E₂ metabolism in human colorectal cancer liver metastases

Background: Prostaglandin (PG) E₂ plays a critical role in colorectal cancer (CRC) progression, including epithelial-mesenchymal transition (EMT). Activity of the rate-limiting enzyme for PGE₂ catabolism (15-hydroxyprostaglandin dehydrogenase [15-PGDH]) is dependent on availability of NAD+. We tested the hypothesis that there is intra-tumoral variability in PGE₂ content, as well as in levels and activity of 15-PGDH, in human CRC liver metastases (CRCLM). To understand possible underlying mechanisms, we investigated the relationship between hypoxia, 15-PGDH and PGE₂ in human CRC cells in vitro. Methods: Tissue from the periphery and centre of 20 human CRCLM was analysed for PGE₂ levels, 15-PGDH and cyclooxygenase (COX)-2 expression, 15-PGDH activity, and NAD+/NADH levels. EMT of LIM1863 human CRC cells was induced by transforming growth factor (TGF) β. Results: PGE₂ levels were significantly higher in the centre of CRCLM compared with peripheral tissue (P = 0.04). There were increased levels of 15-PGDH protein in the centre of CRCLM associated with reduced 15-PGDH activity and low NAD+/NADH levels. There was no significant heterogeneity in COX-2 protein expression. NAD+ availability controlled 15-PGDH activity in human CRC cells in vitro. Hypoxia induced 15-PGDH expression in human CRC cells and promoted EMT, in a similar manner to PGE₂. Combined 15-PGDH expression and loss of membranous E-cadherin (EMT biomarker) were present in the centre of human CRCLM in vivo.Conclusions: There is significant intra-tumoral heterogeneity in PGE₂ content, 15-PGDH activity and NAD+ availability in human CRCLM. Tumour micro-environment (including hypoxia)-driven differences in PGE₂ metabolism should be targeted for novel treatment of advanced CRC

Model Uncertainties in FEM Analyses of Punching Failures of Concrete Slabs

Punching shear is a type of failure of reinforced concrete slabs subjected to localized forces. This failure has been examined by many researchers experimentally, analytically or numerically. Empirical equations based on tests observations are nowadays the basis of the existing design codes. The work described herein presents 3D Finite elements method (FEM) analysis of three slab-column connections also tested experimentally to investigate the three fundamental geometries: central, side and corner column. The sensitivity of the FEM response to input parameters such as material constitutive laws is studied. Concrete constitutive models are described in detail, including their effects on the accuracy of FEM analysis. The comparison between FEM results, experimental tests, code provisions and a new model for punching based on the compression chord capacity model is presented. As a conclusion, an estimation of the model uncertainties related to FEM analyses of punching failures without shear reinforcement is discusse

Skew Reinforcement Optimization in Concrete Shells subject to Uncertain Loading Conditions

In structural design, structures are often modeled using the finite element method (FEM). One of the most common element types is the shell, which is used to model surfaces in three dimensional space when the surface thickness is less than the other two dimensions. Designers are generally interested in providing a solution that respects all the problem constraints, without trying to further improve it as optimization is not trivial even if it could yield great benefit both from the economic and the construction point of view. Additionally, saving materials is one of the fundamental criteria for the sustainable approach to the design. In this paper we address the skew reinforcement design in reinforced concrete two dimensional elements (SRD2D) subject to multiple loading conditions. It consists of determining the minimum reinforcement required to respect all the constraints given by the geometric properties and the internal actions working on it, for all the loading conditions that may occur, i.e. for different combinations of internal actions acting on the element. We present a heuristic framework that guides a genetic algorithm. Computational results show the efficacy and the effectiveness of the method

A hybrid genetic algorithm for skew reinforcement minimization in concrete shell finite elements

In structural design, structures are often modeled using the finite elements method (FEM). One of the most common element type is the shell, which is used to model surfaces in three dimensional space as far as the surface thickness is smaller than the other two dimensions. Designers are generally interested in providing a solution that respects all the problem constraints and guarantees structural safety [1], without trying to further improve it as optimization is not trivial even if it could yield a huge benefit both from the economic and the construction point of view. Additionally, saving materials is one of the fundamental criteria for the sustainable approach to the design. In this paper we address the Skew Reinforcement Design in Reinforced Concrete Two Dimensional Elements (SRD2D) under multiple loading conditions. It consists of determining the minimum reinforcement required to respect all the constraints given by the geometric properties and the internal actions working on it, for all the loading conditions that may occur, i.e. for different combinations of internal actions acting on the element. We present a heuristic framework that guides a Genetic Algorithm. Computational results show the efficacy and the effectiveness of the method

A hybrid genetic algorithm for skew reinforcement minimization in concrete shell finite elements

In structural design, structures are often modeled using the finite elements method (FEM). One of the most common element type is the shell, which is used to model surfaces in three dimensional space as far as the surface thickness is smaller than the other two dimensions. Designers are generally interested in providing a solution that respects all the problem constraints and guarantees structural safety [1], without trying to further improve it as optimization is not trivial even if it could yield a huge benefit both from the economic and the construction point of view. Additionally, saving materials is one of the fundamental criteria for the sustainable approach to the design. In this paper we address the Skew Reinforcement Design in Reinforced Concrete Two Dimensional Elements (SRD2D) under multiple loading conditions. It consists of determining the minimum reinforcement required to respect all the constraints given by the geometric properties and the internal actions working on it, for all the loading conditions that may occur, i.e. for different combinations of internal actions acting on the element. We present a heuristic framework that guides a Genetic Algorithm. Computational results show the efficacy and the effectiveness of the method

Comparison between safety formats in nonlinear analysis of a reinforced concrete structure

The focus of the present work is on the assessment of design value Rd of the load bearing capacity of a reinforced concrete beam by means of a non-linear finite element model and a safety format. The RC structure under investigation is a simply supported beam with a span length of approximately 5.7 m and with nine circular holes in the web, with a diameter of 0.3 m and a spacing of 0.63 m. The partial factor and the global resistance safety formats are compared and the results obtained with each procedure are discussed