Simulated-Physiological Loading Conditions Preserve Biological and Mechanical Properties of Caprine Lumbar Intervertebral Discs in Ex Vivo Culture

Low-back pain (LBP) is a common medical complaint and associated with high societal costs. Degeneration of the intervertebral disc (IVD) is assumed to be an important causal factor of LBP. IVDs are continuously mechanically loaded and both positive and negative effects have been attributed to different loading conditions

Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals.

BACKGROUND: Elevated plasma homocysteine is a risk factor for Alzheimer disease, but the relevance of homocysteine lowering to slow the rate of cognitive aging is uncertain. OBJECTIVE: The aim was to assess the effects of treatment with B vitamins compared with placebo, when administered for several years, on composite domains of cognitive function, global cognitive function, and cognitive aging. DESIGN: A meta-analysis was conducted by using data combined from 11 large trials in 22,000 participants. Domain-based z scores (for memory, speed, and executive function and a domain-composite score for global cognitive function) were available before and after treatment (mean duration: 2.3 y) in the 4 cognitive-domain trials (1340 individuals); Mini-Mental State Examination (MMSE)-type tests were available at the end of treatment (mean duration: 5 y) in the 7 global cognition trials (20,431 individuals). RESULTS: The domain-composite and MMSE-type global cognitive function z scores both decreased with age (mean ± SE: -0.054 ± 0.004 and -0.036 ± 0.001/y, respectively). Allocation to B vitamins lowered homocysteine concentrations by 28% in the cognitive-domain trials but had no significant effects on the z score differences from baseline for individual domains or for global cognitive function (z score difference: 0.00; 95% CI: -0.05, 0.06). Likewise, allocation to B vitamins lowered homocysteine by 26% in the global cognition trials but also had no significant effect on end-treatment MMSE-type global cognitive function (z score difference: -0.01; 95% CI: -0.03, 0.02). Overall, the effect of a 25% reduction in homocysteine equated to 0.02 y (95% CI: -0.10, 0.13 y) of cognitive aging per year and excluded reductions of >1 mo per year of treatment. CONCLUSION: Homocysteine lowering by using B vitamins had no significant effect on individual cognitive domains or global cognitive function or on cognitive aging

Interval Modulation: A New Paradigm for the Design of High Speed Communication Systems

In this thesis we propose a new, biologically inspired, paradigm for the design of high speed communication systems. The paradigm consists of a new modulation format referred to as Interval Modulation (IM). In order to transmit data in an efficient manner using this format, new coding techniques are needed. In this thesis we propose a coding technique based on variable length to variable length prefix trees and code construction algorithms are outlined. These codes are referred to as Interval Modulation Codes (IMC). Furthermore, data encoded with this modulation format cannot be transmitted or received using conventional synchronous CDR based receivers. In this thesis we outline a new asynchronous circuit architecture for both the transmitter and receiver. The architecture is based on active delay lines and eliminates the need for clock recovery

Developing Bioreactors to Host Joint-Derived Tissues That Require Mechanical Stimulation

Demographics of the Western Societies points toward an elderly population in need of research on replacement parts for joints and their components, such as the meniscus, cartilage, ligaments, tendons, and intervertebral discs. There is a lack of basic research to predict treatment options before degeneration or inflammation has progressed, and at late stages, when regeneration might not be an option anymore. Thus, to achieve a better understanding of the current specific problems in orthopedic research, there is a need for clinically relevant mechanobiological models. Animal experiments, especially those on large animals, are costly and, in some cases, doubtful as regards clinical translation. Ex vivo bioreactors that allow biomechanical loading are aimed to mimic the in vivo situation of critical joints that are prone to failure. These tissues often require unique adaptations prior and during organ culture as these are often under mechanical forces in situ. On the one hand, ex vivo organ cultures are limited in regarding the size and cell numbers that can be kept alive and the duration of experiments. However, a strong asset of these cultures is the use of primary human material, which is a chance to provide more translational relevant results. Within this book chapter, we give a brief history of general concepts for bioreactor constructions in the field of orthopedic research and give some recent examples for tendons, the knee joint and the intervertebral disc. We offer a summary of the current state of the art, pitfalls and limitations in the design and the future challenges