Phenotypes Determined by Cluster Analysis and Their Survival in the Prospective European Scleroderma Trials and Research Cohort of Patients With Systemic Sclerosis

Objective: Systemic sclerosis (SSc) is a heterogeneous connective tissue disease that is typically subdivided into limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc) depending on the extent of skin involvement. This subclassification may not capture the entire variability of clinical phenotypes. The European Scleroderma Trials and Research (EUSTAR) database includes data on a prospective cohort of SSc patients from 122 European referral centers. This study was undertaken to perform a cluster analysis of EUSTAR data to distinguish and characterize homogeneous phenotypes without any a priori assumptions, and to examine survival among the clusters obtained. / Methods: A total of 11,318 patients were registered in the EUSTAR database, and 6,927 were included in the study. Twenty‐four clinical and serologic variables were used for clustering. / Results: Clustering analyses provided a first delineation of 2 clusters showing moderate stability. In an exploratory attempt, we further characterized 6 homogeneous groups that differed with regard to their clinical features, autoantibody profile, and mortality. Some groups resembled usual dcSSc or lcSSc prototypes, but others exhibited unique features, such as a majority of lcSSc patients with a high rate of visceral damage and antitopoisomerase antibodies. Prognosis varied among groups and the presence of organ damage markedly impacted survival regardless of cutaneous involvement. / Conclusion: Our findings suggest that restricting subsets of SSc patients to only those based on cutaneous involvement may not capture the complete heterogeneity of the disease. Organ damage and antibody profile should be taken into consideration when individuating homogeneous groups of patients with a distinct prognosis

Relationship between Inertial features of the upper extremity and simple reaction time in boys and girls aged 17-18

The latent period of visual sensor motor reaction depends, in part, on the sensory and integrative processes in the brain, but is also influenced by the rate of the muscle contraction. There is no clear evidence in the literature whether the rotational inertia of segments of limbs has any direct effect on the reaction time. The aim of our study was to identify this relationship . The study involved 566 right handed students aged 16–17 of both genders beginning their post puberty period. Reaction time was measured during experimental adduction of the forearm and hand, using a special rotating handle and lever connected to a computer that recorded the reaction time (~1 ms). Calculations of the rotational inertia were carried out using regression models by Zatsiorsky and other authors. Each gender group was divided into three subgroups: with high, medium and low values of rotational inertia. It was found that individuals with high values of rotational inertia of forearm and wrist demonstrated significantly longer reaction times. This pattern was apparent in both gender groups. Although males illustrated greater values of rotational inertia than females they demonstrated relatively shorter reaction times. This contradiction can be explained by greater muscle power of young men. We recommend taking into account the amount of rotational inertia of the responsive segment in all kinds of research which require measurement of reaction time. The article was translated by the authors

Making molecular machines work

In this review we chart recent advances in what is at once an old and very new field of endeavour — the achievement of control of motion at the molecular level including solid-state and surface-mounted rotors, and its natural progression to the development of synthetic molecular machines. Besides a discussion of design principles used to control linear and rotary motion in such molecular systems, this review will address the advances towards the construction of synthetic machines that can perform useful functions. Approaches taken by several research groups to construct wholly synthetic molecular machines and devices are compared. This will be illustrated with molecular rotors, elevators, valves, transporters, muscles and other motor functions used to develop smart materials. The demonstration of molecular machinery is highlighted through recent examples of systems capable of effecting macroscopic movement through concerted molecular motion. Several approaches to illustrate how molecular motor systems have been used to accomplish work are discussed. We will conclude with prospects for future developments in this exciting field of nanotechnology.