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Little is known about the impact behavior of composite fixation plate used in the fracture healing of long bones diaphysis. Hence, this study examined polypropylene composite fixation plates using different glass fibers and measured their biomechanical responses under axial impact loading experimentally and numerically. Short randomly oriented, long unidirectional prepregs and fiber yarn of glass were considered as reinforcements, and fixation plates were fabricated through two different heat-compressing and 3D printing processes. Furthermore, assessing the fixation plate structures impact behavior was carried out using in vitro impact test and finite element analysis (FEA). Impact damping behavior, damage mechanisms, and stress and strain pattern of the composite fixation plate structures were obtained under various bone fractures and impact energies. The impact load-time responses and the failure mechanisms demonstrated that fixation plate structures with more plastic behavior and lower stiffness could act as an initial shock absorber and dampen the transmission of axial impact load by distributing the impact energy over time. Therefore, considering the ability of stress shielding and adequate interfragmentary movement which amplifies bone ossification, the proposed Glass Fiber/PP (GF/PP) composite fixation plates could serve as a proper alternative in orthopedics. [Abstract copyright: Copyright © 2021 Elsevier Ltd. All rights reserved.]

This paper investigates the role of sentiment in the US macro economy from 1920 to 1934. We use 2.4 million digitized articles from the Wall St Journal to algorithmically derive a monthly sentiment index. A ten variable vector error correction model is then used to identify shocks to sentiment that are orthogonal to the fundamentals of the economy. We show that the identified "pure" sentiment shocks have economically significant effects on Industrial Production, the S&P500 stock index, money supply (M2), credit spreads, terms spreads, interest rates and prices. We are further able to delineate both the timing and strength of the shocks and their subsequent effects on the economy using historical decompositions. These suggest impacts of up to 9%.

Metallic bone fixations, due to their high rigidity, can cause long-term complications. To alleviate metallic biomaterials’ drawbacks, in this research new Glass Fiber/Polypropylene (GF/PP) composite internal fixations were developed, and an investigation of their mechanical behavior was performed through in vitro biomechanical experiments. Short randomly oriented, long unidirectional prepreg, and long unidirectional fiber yarn were considered as reinforcements, and the effects on their mechanical properties of different manufacturing processes, that is, 3D printing and heat-compressing, were investigated. The constructed fixation plates were tested in the transversely fractured diaphysis of bovine tibia under axial compression loading. The overall stiffness and the Von Mises strain field of the fixation plates were obtained within stable and unstable fracture conditions. The samples were loaded until failure to determine their failure loads, strains, and mechanisms. Based on the results, the GF/PP composite fixation plates can provide adequate interfragmentary movement to amplify bone ossification, so they can provide proper support for bone healing. Moreover, their potential for stress shielding reduction and their load-bearing capacity suggest their merits in replacing traditional metallic plates.

Mechanical properties and manufacturing processes of Glass Fiber/Polypropylene (GF/PP) composites for application of flexible internal long bone fracture fixation plates have been investigated. PP/Short Chopped Glass Fiber (PPSCGF), PP/Long Glass Fiber (PPLGF) and PP/Long Glass Fiber Yarn (PPLGFY) were used in fabrication of the fixation plates. The PPSCGF and PPLGF plates were made by the heat-compressing process and Three-dimensional (3D) printing method was used to make the PPLGFY ones. The values of Young’s modulus, tensile strength, flexural modulus and strength, and impact strength of the PPSCGF in the fiber longitudinal direction were found to be [Formula: see text]GPa, [Formula: see text]MPa, [Formula: see text]GPa, [Formula: see text]MPa and [Formula: see text]kJ/m2, respectively. Where, these values for the PPLGF were to [Formula: see text]GPa, [Formula: see text]MPa, [Formula: see text]GPa, [Formula: see text]MPa, and [Formula: see text]kJ/m2 and for the PPLGFY were to [Formula: see text]GPa, [Formula: see text]MPa, [Formula: see text]GPa, [Formula: see text]MPa and [Formula: see text]kJ/m2. These have been found to be in close agreement with the human bone properties. Furthermore, the strength and modulus values of the plates were reasonable to be used as a bone implant applicable for bone fracture reconstructions. Hence, the study concluded that the GF/PP composites are useful for load-bearing during daily activities and would be recommended as a choice in orthopedic fixation plate applications. It will help the researchers for development of new fixation designs and the clinicians for better patient’s therapy in future.

John Maynard Keynes composed The General Theory as a response to the Great Crash and Great Depression with all their devastating consequences for the US macro economy and financial markets, as well as the rest of the world. The role of expectations his new theory set out has been widely accepted. The role of “animal spirits” he proscribed (i.e. the role of emotion in cognition) has remained much more controversial. We analyse over two million digitally stored news articles from The Wall St Journal to construct a sentiment series that we use to measure the role of emotion at the time Keynes wrote. An eight variable vector error correction model is then used to identify shocks to sentiment that are orthogonal to the fundamentals of the economy. We show that the identified “pure” sentiment shocks do have statistically and economically significant effects on output, money supply (M2), and the stock market for periods of the 1920s.

There is a debate about the effect of the extremely low, or even negative, interest rate regime on bank profitability. On the one hand it raises demand and thereby adds to bank profits, while on the other hand it lowers net interest margins, especially at the Zero Lower Bound. In this paper we review whether the prior paper by Altavilla, Boucinha and Peydro (2018) on this question for the Eurozone can be generalized to other monetary blocs, i.e. USA and UK. While our findings have some similarity with their earlier work, we are more concerned about the possible negative effects of this regime, not only on bank profitability but also on bank credit extension more widely.