Evidence of epistasis between Interleukin-1 and Selenoprotein-S with susceptibility to rheumatoid arthritis

Objective: Selenoprotein-S (SELS) is involved in the stress response within the endoplasmic reticulum (ER) and inflammation. Recently, promoter variants in the SELS gene were shown to be associated with plasma levels of interleukin (IL)6, IL1β and tumour necrosis factor (TNF). It was hypothesised that these variants could influence rheumatoid arthritis (RA) susceptibility and may interact with functional single nucleotide polymorphisms (SNPs) in the genes for IL1, IL6 and TNF. Methods: Genotyping was performed in 988 unrelated healthy controls and 965 patients with RA. Stratified analysis was used to test for interactions. Single gene effects and evidence of epistasis were investigated using the Mantel–Haenszel (M–H) test and the linkage disequilibrium (LD)-based statistic. Results: No association of SELS −105 genotype and RA susceptibility was detected. Stratification of SELS −105 genotypes by IL1 −511 genotypes showed that the disease risk (comparing AA/GA to GG at the SELS −105 locus) in individuals with the GG/AG genotype at the IL1β −511 locus was significantly lower than that in individuals having the AA genotype at the IL1β −511 locus (odds ratio (OR): 0.9 and 2.3, respectively; p = 0.004 by M–H test). Significant epistasis was also detected using the LD-based statistic (p = <0.001). No interaction was observed between SELS −105 and IL6 or TNF variants. Conclusion: Our results reveal evidence of strong epistasis in two genes in the IL1 production pathway and highlight the potential importance of gene–gene interactions in the pathogenesis of RA

A note on the use of reduced transport fluid (RTF) for isolation of Neisseria gonorrhoeae

Swabs containing pus from urethral discharges obtained from 55 male patients attending venereal disease clinics were transported in Stuart's transport medium or RTF (reduced transport fluid) and then cultured on ThayerMartin plates. Forty-eight swabs showed the presence of Neisseria in smears and 45 gave good growth of N. gonorrhoeae when cultured 18 - 24 hours after the swabs were taken from the patient.S. Afr. Med. J., 48, 1195 (1974)

Additive Manufacturing and Physicomechanical Characteristics of PEGDA Hydrogels: Recent Advances and Perspective for Tissue Engineering

In this brief review, we discuss the recent advancements in using poly(ethylene glycol) diacrylate (PEGDA) hydrogels for tissue engineering applications. PEGDA hydrogels are highly attractive in biomedical and biotechnology fields due to their soft and hydrated properties that can replicate living tissues. These hydrogels can be manipulated using light, heat, and cross-linkers to achieve desirable functionalities. Unlike previous reviews that focused solely on material design and fabrication of bioactive hydrogels and their cell viability and interactions with the extracellular matrix (ECM), we compare the traditional bulk photo-crosslinking method with the latest three-dimensional (3D) printing of PEGDA hydrogels. We present detailed evidence combining the physical, chemical, bulk, and localized mechanical characteristics, including their composition, fabrication methods, experimental conditions, and reported mechanical properties of bulk and 3D printed PEGDA hydrogels. Furthermore, we highlight the current state of biomedical applications of 3D PEGDA hydrogels in tissue engineering and organ-on-chip devices over the last 20 years. Finally, we delve into the current obstacles and future possibilities in the field of engineering 3D layer-by-layer (LbL) PEGDA hydrogels for tissue engineering and organ-on-chip devices

Compact Lattice QED and the Coulomb Potential

The potential energy of a static charge distribution on a lattice is rigorously computed in the standard compact quantum electrodynamic model. The method used follows closely that of Weyl for ordinary quantum electrodynamics in continuous space-time. The potential energy of the static charge distribution is independent of temperature and can be calculated from the lattice version of Poisson's equation. It is the usual Coulomb potential.Comment: 6 pages, includes one figure in Topdrawer, NUB 3054/9

Health Literacy in Community Pharmacy

48% of English-speaking patients are unable to obtain, process, understand, and utilize health information, and 30-50% of patients do not correctly adhere to their medications. The combination of chronic disease, poor heath literacy, and poor medication adherence lead to increased health costs and hospitalizatio

On Selecting and Scheduling Assembly Plans Using Constraint Programming

This work presents the application of Constraint Programming to the problem of selecting and sequencing assembly operations. The set of all feasible assembly plans for a single product is represented using an And/Or graph. This representation embodies some of the constraints involved in the planning problem, such as precedence of tasks, and the constraints due to the completion of a correct assembly plan. The work is focused on the selection of tasks and their optimal ordering, taking into account their execution in a generic multi-robot system. In order to include all different constraints of the problem, the And/Or graph representation is extended, so that links between nodes corresponding to assembly tasks are added, taking into account the resource constraints. The resultant problem is mapped to a Constraint Satisfaction Problem (CSP), and is solved using Constraint Programming, a powerful programming paradigm that is increasingly used to model and solve many hard real-life problems

A Genetic Algorithm for Assembly Sequence Planning

This work presents a genetic algorithm for assembly sequence planning. This problem is more difficult than other sequencing problems that have already been tackled with success using these techniques, such as the classic Traveling Salesperson Problem (TSP) or the Job Shop Scheduling Problem (JSSP). It not only involves the arranging of tasks, as in those problems, but also the selection of them from a set of alternative operations. Two families of genetic operators have been used for searching the whole solution space. The first includes operators that search for new sequences locally in a predetermined assembly plan, that of parent chromosomes. The other family of operators introduces new tasks in the solution, replacing others to maintain the validity of chromosomes, and it is intended to search for sequences in other assembly plans. Furthermore, some problem-based heuristics have been used for generating the individuals in the population

Nanoindentation Response of 3D Printed PEGDA Hydrogels in a Hydrated Environment

Hydrogels are commonly used materials in tissue engineering and organ-on-chip devices. This study investigated the nanomechanical properties of monolithic and multilayered poly(ethylene glycol) diacrylate (PEGDA) hydrogels manufactured using bulk polymerization and layer-by-layer projection lithography processes, respectively. An increase in the number of layers (or reduction in layer thickness) from 1 to 8 and further to 60 results in a reduction in the elastic modulus from 5.53 to 1.69 and further to 0.67 MPa, respectively. It was found that a decrease in the number of layers induces a lower creep index (CIT) in three-dimensional (3D) printed PEGDA hydrogels. This reduction is attributed to mesoscale imperfections that appear as pockets of voids at the interfaces of the multilayered hydrogels attributed to localized regions of unreacted prepolymers, resulting in variations in defect density in the samples examined. An increase in the degree of cross-linking introduced by a higher dosage of ultraviolet (UV) exposure leads to a higher elastic modulus. This implies that the elastic modulus and creep behavior of hydrogels are governed and influenced by the degree of cross-linking and defect density of the layers and interfaces. These findings can guide an optimal manufacturing pathway to obtain the desirable nanomechanical properties in 3D printed PEGDA hydrogels, critical for the performance of living cells and tissues, which can be engineered through control of the fabrication parameters