Signorini-Type Problems over Non-Convex Sets for Composite Bodies Contacting by Sharp Edges of Rigid Inclusions

A new type of non-classical 2D contact problem formulated over non-convex admissible sets is proposed. Specifically, we suppose that a composite body in its undeformed state touches a wedge-shaped rigid obstacle at a single contact point. Composite bodies under investigation consist of an elastic matrix and a rigid inclusion. In this case, the displacements on the set, corresponding to a rigid inclusion, have a predetermined structure that describes possible parallel shifts and rotations of the inclusion. The rigid inclusion is located on the external boundary and has the form of a wedge. The presence of the rigid inclusion imposes a new type of non-penetration condition for certain geometrical configurations of the obstacle and the body near the contact point. The sharp-shaped edges of the obstacle effect such sets of admissible displacements that may be non-convex. For the case of a thin rigid inclusion, which is described by a curve and a volume (bulk) rigid inclusion specified in a subdomain, the energy minimization problems are formulated. The solvability of the corresponding boundary value problems is proved, based on analysis of auxiliary minimization problems formulated over convex sets. Qualitative properties of the auxiliary variational problems are revealed; in particular, we have found their equivalent differential formulations. As the most important result of this study, we provide justification for a new type of mathematical model for 2D contact problems for reinforced composite bodies.

Numerical and Experimental Investigations On Cross-sensitivity Characteristics of Instrumented Wheelset Associated with Longitudinal Force and Lateral Contact Position

It is crucial to grasp wheel-rail contact forces in the evaluation of running safety and curving performance of railway vehicles. To measure the wheel-rail contact forces, instrumented wheelset, which has the strain gauges on the wheel surface, is widely used. The purpose of this research is to increase the measurement accuracy of the wheel-rail contact forces by understanding the detailed characteristics of the instrumented wheelset. Although the various research works on the instrumented wheelset have been carried out to increase the measurement accuracy of wheel-rail contact forces, there are few works considering the longitudinal force and the lateral shift of the wheel-rail contact point. However, sometimes the longitudinal force has a non-negligible influence on the measurement accuracy on the instrumented wheelset. In this paper, the authors clarify the cross-sensitivity characteristics of the instrumented wheelset when the longitudinal force is applied to the various lateral position on the wheel tread through the FEM analysis and the static load test. The authors also propose a method to approximate the cross-sensitivity as an analytical function of the lateral and circumferential contact positions.

The Application of Salutogenesis in Primary Care

Primary care is understood as the first contact point to medical care. It operates at the interface between the social and the health systems, between the patient with his or her family and the professional environment, and refers to the local population, while primary health care, following WHO, is defined as a whole-of-society approach envisioned to contribute to universal health coverage and equality. This chapter is dedicated primarily to the application of salutogenesis in primary care. Since primary care services are a complex of strongly interrelated professional practice, research, and supporting policy, applying salutogenesis in primary care comprehensively should introduce salutogenesis in all these fields simultaneously.This chapter examines how salutogenesis is addressed and discussed in policy, research, and practice of primary care and discusses the application of salutogenesis as an orientation, a model, and the construct of ‘sense of coherence’. Thus, it contributes to supporting the application of salutogenesis in primary care and provides an outlook on further research needs.

Non-smooth dynamic modeling and simulation of an unmanned bicycle on a curved pavement

The non-smooth dynamic model of an unmanned bicycle is established to study the contact-separate and stick-slip non-smooth phenomena between wheels and the ground. According to the Carvallo-Whipple configuration, the unmanned bicycle is reduced to four rigid bodies, namely, rear wheel, rear frame, front fork, and front wheel, which are connected by perfect revolute joints. The interaction between each wheel and the ground is simplified as the normal contact force and the friction force at the contact point, and these forces are described by the Hunt-Crossley contact force model and the LuGre friction force model, respectively. According to the characteristics of flat and curved pavements, calculation methods for contact forces and their generalized forces are presented. The dynamics of the system is modeled by the Lagrange equations of the first kind, a numerical solution algorithm of the dynamic equations is presented, and the Baumgarte stabilization method is used to restrict the drift of the constraints. The correctness of the dynamic model and the numerical algorithm is verified in comparison with the previous studies. The feasibility of the proposed model is demonstrated by simulations under different motion states.

Prediction of SARS-CoV-2 Omicron Variant Immunogenicity, Immune Escape and Pathogenicity, through Analysis of Spike Protein-specific Core Unique Peptides

The recently discovered Omicron variant of the SARS-CoV-2 corona virus has raised a new, global, awareness, since it is considered as a new variant of concern from all major health organizations, including WHO and ECDC. Omicron variant is characterized by 30 amino acid changes, three small deletions and one small insertion in the Spike protein. In this study, we have identified the Core Unique Peptides (CrUPs) that reside exclusively in the Omicron variant of Spike protein and are absent from the human proteome, thus creating a new dataset of peptides named as C/H-CrUPs. Furthermore, we have analyzed their protein locations and compared them with the respective ones of Alpha and Delta SARS-CoV-2 variants. In Omicron, 115 C/H-CrUPs were generated and 119 C/H-CrUPs were lost, almost four times as many compared to the other two variants. From position 440 to position 508, at the Receptor Binding Motif (RBM), 8 mutations were detected, resulting in the construction of 28 novel C/H-CrUPs. Most importantly, in Omicron variant, new C/H-CrUPs carrying two or three mutant amino acids were produced, as a consequence of the accumulation of multiple mutations in the RBM. Remarkably, these Omicron-derived C/H-CrUPs that bear several mutated amino acids could not be recognized in any other viral Spike variant. We suggest that virus binding to the ACE2 receptor is facilitated by the herein identified C/H-CrUPs in contact point mutations and Spike-cleavage sites, while the immunoregulatory NF9 peptide is not detectably affected. Taken together, our findings indicate that Omicron variant contains intrinsic abilities to escape immune-system attack, while its mutations can mediate strong viral binding to the ACE2 receptor, leading to highly efficient fusion of the virus to the target cell. However, the intact NF9 peptide suggests that Omicron exhibits reduced pathogenicity compared to Delta variant.

Student Support and Transition Through a Buddy Programme to Foster Social Integration

The University of Pretoria (UP) began offering formal academic student support in 2011 when the first faculty student advisor (FSA) was appointed. Although many more FSAs were subsequently appointed, assistance to all the students in need of support remained insufficient. However, financial assistance through the collaboration grant received from the Department of Higher Education and Training in 2018 made it possible to explore new areas of support. The UP was able to pilot four innovations due to the availability of additional funds. These included generic workshops across faculties; the creation of a hub in the library, which served as a common contact point for students requiring assistance; the appointment of peer advisors; and a Buddy Programme for first-year students. This article explains the Buddy Programme as perceived by the senior students who mentored the first-year students. The mentors are known as “big buddies”. Our work on this programme is based on Tinto’s (1975) ideas about social integration. The Buddy Programme was introduced to assist first-year students in their transition from school to university life. This paper highlights the challenges that first-year students faced and it explains how the concepts could become institutionalised once university activities have been normalised in the post-pandemic future.

Rhinogenic contact point headache in pediatric age group: a review

Headache is a common clinical entity of pediatric patients in routine clinical practice. Anatomical variation in the nasal cavity may result in headaches due to contact of the opposing mucosal surfaces, called rhinogenic contact point headache (RCPH). RCPH has recently begun to be of interest among clinicians and is accepted as a cause of headache by international headache society classification. The pressure of the two opposing mucosal surfaces in the nasal cavity without any evidence of inflammation can be an etiology for headache or facial pain. Anatomical variations in the nasal cavity like deviated nasal septum (DNS), spur, concha bullosa, hypertrophied inferior turbinate, medialized middle turbinate, and septal bullosa are important causes for contact point headache. RCPH is often misdiagnosed by clinicians during the assessment of headaches in pediatric patients and is sometimes considered a headache of unknown etiology. Endoscopic examination of the nasal cavity and computed tomography (CT) scans are important tools for the diagnosis of anatomical variations in the nasal cavity causing RCPH. Endoscopic resection of the contact point in the nasal cavity is the treatment of choice. There is not much literature for RCPH in pediatric patients, indicating that these clinical entities are neglected. This review article discusses the details of the epidemiology, etiopathology, clinical manifestations, diagnosis, treatment of the RCPH in pediatric patients.

A study On Support Selection Mechanism In Tendrils of Cayratia Japonica

Organisms make decisions when they perceive cues of varying intensities. In case of climbing plants, the diameter of supports in contact (tree or stem) is an important cue for their growth as plants that coil around a support with large diameter are unable to maintain tensional forces required for continued attachment to the support. The negative association between the diameter and the climbing success has been reported since Darwin published his study on climbing plants. However, it is not known if a climbing plant makes a decision to avoid a support with larger diameter. Here, we tested this possibility by observing the coiling response of tendrils of Cayratia japonica to supports with different diameters. The coiling success of the tendrils was affected by the diameter of the support and the tendril lengths. We described the branching pattern of coiling response and demonstrated that the tendrils change their coiling shape depending on the support diameter and the tendril length. To understand the behavioural rules regulating the branching, we constructed a simple model with two assumptions on the tendril movement, (1) when the tendrils receive a contact stimulus, they begin to coil from around the contact point and (2) there is a minimum coiling angle at which the tendrils coil up, once the tendril starts coiling. Image analysis and 3D motion tracking technique revealed that the movement of the tendrils were consistent with the two assumptions of the model. The results suggested that the tendrils flexibly changed the coiling shapes depending on the support diameter and simple behavioural rules could regulate this diameter-dependent response.