Novel KCND3 Variant Underlying Nonprogressive Congenital Ataxia or SCA19/22 Disrupt KV4.3 Protein Expression and K+ Currents with Variable Effects on Channel Properties

KCND3 encodes the voltage-gated potassium channel K_V4.3 that is highly expressed in the cerebellum, where it regulates dendritic excitability and calcium influx. Loss-of-function K_V4.3 mutations have been associated with dominant spinocerebellar ataxia (SCA19/22). By targeted NGS sequencing, we identified two novel KCND3 missense variants of the K_V4.3 channel: p.S347W identified in a patient with adult-onset pure cerebellar syndrome and p.W359G detected in a child with congenital nonprogressive ataxia. Neuroimaging showed mild cerebellar atrophy in both patients. We performed a two-electrode voltage-clamp recording of K_V4.3 currents in Xenopus oocytes: both the p.G345V (previously reported in a SCA19/22 family) and p.S347W mutants exhibited reduced peak currents by 50%, while no K+ current was detectable for the p.W359G mutant. We assessed the effect of the mutations on channel gating by measuring steady-state voltage-dependent activation and inactivation properties: no significant alterations were detected in p.G345V and p.S347W disease-associated variants, compared to controls. K_V4.3 expression studies in HEK293T cells showed 53% (p.G345V), 45% (p.S347W) and 75% (p.W359G) reductions in mutant protein levels compared with the wildtype. The present study broadens the spectrum of the known phenotypes and identifies additional variants for KCND3-related disorders, outlining the importance of SCA gene screening in early-onset and congenital ataxia.     

Linking Contradictions and Laws of Engineering System Evolution within the TRIZ Framework

Tools and methods developed during the era of quality and optimization have shown their limitations and become inappropriate in the context of the requirements of innovation. Nowadays the need to rebuild design practices in enterprises is strongly felt both in terms of human skills and methodological expertise. In part, a way to face the innovation era's difficulties has been provided through the theory of inventive problem solving. This theory represents a significant breakthrough in driving problem statement and solving in a direction that is expressed through the idea that technical systems are driven by objective laws. A second postulate concerns the notion of contradiction, but so far only few contributions have addressed the relations between laws and contradictions. This paper, through a qualitative approach, presents a solution to this limitation and proposes a possible use of laws within the choice of the appropriate conflicting pair, prior to the use of any TRIZ solving techniques. Tests to observe the impact of the proposed approach were conducted in a French engineering ‘grande école’ during three semesters with 180 engineers. The contribution of this paper is twofold. On the one hand, there is a theoretical contribution to the theory of inventive problem solving. In addition, the proposed method offers especially TRIZ practitioners new ways for problem understanding and problem formulation.     

In-vitro iron dialysability from legumes: Influence of phytate and extrusion cooking

In-vitro iron dialysability from five Italian legumes (mottled bean, white bean, faba bean, chickpea, lentil) and the influence of phytate and extrusion cooking on it were evaluated. Iron dialysability was 2·3 and 2·4% in mottled and white bean respectively, 1·2% infaba bean, 2·7% in chickpea and 1·1% in lentil. After extrusion cooking the flours showed a marked iron contamination and a decrease in iron dialysability, but these changes were significant only for mottled bean. Enzymic phytate removal induced an increase in iron dialysability > 100% in all the raw legumes except mottled bean which showed an increase of only 57%. This finding indicates that, although phytate consistently modifies iron dialysability, it is difficult to identify a quantitative relationship between phytate content and iron dialysability.     

How to recognize the order of infinitesimal mechanisms: A numerical approach

Structures presenting kinematical inderterminacy are usually called mechanisms. This paper is entirely concerned with assemblies which reveal themselves to be mechanisms at a null value of the load. Among them a first distinction is made between infinitesimal and finite ones, the former being characterized by one or several directions of lower (but not zero) stiffness, whereas the latter show at least one finite admissible displacement for which none of the bars undergoes any elongation. Moreover, there exists the possibility to make a further distinction among the infinitesimal mechanisms, according to which is the order of the stiffness along the direction considered above. The way of evaluating this order is to perform a local analysis of the strain energy of the assembly, once the displacement field is parametrized in terms of a suitable parameter. By means of a finite element technique, this analysis can be easily performed through the numerical approach presented in this report.     

Development and validation of a probabilistic model for notch fatigue strength prediction of tool steels based on surface defects

A new model for the high cycle notch fatigue strength prediction of tool steels subjected to axial loading is proposed, based on previous literatures studies and experimental tests carried out on six different tool steels, including rotating bending fatigue tests on notched specimens, fractographic analyses, hardness, residual stress, and roughness measurements. The novelty is the assumption that surface defects are the main cause of notch fatigue failures of such steels. A probabilistic approach was implemented by modeling size distributions of defects, resulting in the prediction of normal distributions of fatigue strength. Like to other previous models, the effect of steel hardness, surface residual stress, notch severity, and specimen size was also taken into account. Model calibration and validation were performed using the data collected by the experimental activity. Model behavior was investigated by performing a sensitivity analysis, aiming to verify the response to variations of the considered input variables. Prediction errors of only 1.3% (on average) and 3.1% (maximum) resulted from the comparison between model-predicted and experimental notch fatigue strength.     

Nuclear magnetic resonance characterization of high- and ultrahigh-performance concrete: Application to the study of water leaching

In the present study, we show that high-resolution ²⁹Si and ²⁷Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) can be a powerful tool for analyzing actual concrete mixes. The influence of the amount of silica fume and of the type of cement in high-performance concrete (HPC), as well as the influence of the type of silica fume and of the granular packing in ultrahigh-performance concrete (UHPC) were investigated. Significant effects on the amount and shape of C-S-H, on the incorporation of aluminum in the C-S-H structure, and on the distribution of aluminum-containing hydrates were observed. Nuclear magnetic relaxation of protons was also performed and it showed the fractal feature of the pore size distribution in UHPC and the higher amount of larger pores in HPC. The microstructure of the surface of these same formulations leached by mineral water for up to 1 year exhibits slight modifications.