Niederrhein University of Applied Sciences

Patients with knee osteoarthritis (KOA) often have impaired muscle function of the weight-bearing muscles, particularly in the knee and hip joints. This can lead to a significant loss of strength and power and may play a role in the perceived instability of the knee joint. The purpose of this study was to compare the maximum isometric strength of the hip abductor and knee extensor muscles between patients with KOA with and without perceived instability.Nineteen patients with KOA participated in this cross-sectional study and were divided into two groups. The first group (n = 10; women = 4, men = 6, mean age = 67.4 ± standard deviation [SD] 6.4 years) consisted of patients with self-reported instability in the knee joint, and the second group (n = 9; women = 5, men = 4, mean age = 69.6 ± SD 6.7 years) consisted of patients without self-reported instability. Functional and activity limitations were quantified using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Maximum isometric strength of the hip abductors and knee extensors was measured using a belt-mounted handheld dynamometer and expressed as torque (Newton meters [Nm]) by multiplication with the determined lever arm. Torque was normalized to body weight and height.Patients with instability (median WOMAC score = 68) achieved a significantly lower mean torque in hip abduction than the patients without instability (median WOMAC score = 39) (p = 0.01; Cohen’s d = 1.31). There was no significant difference in knee extension torque between the groups (p = 0.202; Cohen’s d = 0.58).KOA patients with instability were able to develop significantly lower hip abductor strength than those without instability, suggesting that targeted strength training of this muscle group may be important for this group of patients.

Utilization of natural fibers in composite materials is a necessity of time due to the rise of user consciousness for lowering the level of environmental pollution.This study presents the comparative anal. of two distinct composites prepared by hand layup method using natural mats (coir fiber, and sugarcane bagasse), and nonwoven glass fiber sheets as reinforcements.The first composite was made with epoxy resin and the second one was made with polyester resin along with the above reinforcements.The composition of the composites and their morphol. of tensile fracture were characterized by FTIR and SEM resp.To compare the mech. properties of the composites, their tensile, bending, and impact strengths were determinedThe tensile strength, flexural rigidity, and impact strength of the glass sheet/ coir fiber/ sugarcane bagasse/ epoxy resin composite (GCSEC) were 59.5 MPa, 110.56 MPa, and 40.85 J resp., whereas, the values were 35.9 MPa, 52.38 MPa, and 32.83 J resp. for the glass sheet/ coir fiber/ sugarcane bagasse/ polyester resin composite (GCSPC).The price of polyester resin is significantly low in comparison with that of epoxy resin.The overall performance of epoxy resin-composite was better; however, the performance of polyester resin-composite was satisfactory as it offered a low-cost hybrid composite.

Semiconductor quantum dots (QDs) possess unique electronic and optical properties, making them promising candidates for applications in light-emitting diodes, solar cells, bioimaging, and photocatalysis. Precise control over their size, shape, and chemical and electronic structure is crucial to ensure the desired functional properties and optimize device performance. However, challenges in QD synthesis and post-synthesis modification persist, especially in large-scale production. This study addresses the classification of QDs synthesized in a tubular flow reactor consisting of a mixture of the desired InP/ZnS core-shell QDs and QDs made from the shell material, i.e., here ZnS QDs formed as a byproduct during the formation step of the ZnS shell. The homogeneous nucleation of ZnS nanoparticles from the shelling material introduces a heterogeneity in size and composition and affects the optical properties of the resulting QDs. To address this issue, we developed a size-selective agglomeration (SSA) technique by incrementally introducing ethanol as a poor solvent and classified the synthesized QDs into 13 distinct fractions. These 13 fractions are sorted into three distinct groups: (i) larger InP/ZnS QDs, (ii) a combination of smaller InP/ZnS QDs and larger ZnS QDs, and (iii) predominant ZnS QDs with some very tiny InP/ZnS QDs. The comprehensive characterization of the fractions was conducted using UV-visible absorption spectroscopy, photoluminescence spectroscopy, high-resolution scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, total reflection X-ray fluorescence, and analytical ultracentrifugation. We could demonstrate that our method effectively separated unwanted ZnS QDs from the target InP/ZnS QDs. In addition, the fractions enriched in smaller InP/ZnS QDs exhibited a higher photoluminescence quantum yield compared to the fractions with larger QDs. This demonstrates the efficacy of SSA in fine-tuning the composition of QD mixtures produced on a larger scale to improve their functional properties. This approach provides fundamental understanding toward the development of a scalable two-dimensional classification process for such ultrasmall nanoparticles by particle size and composition.