Design, Validation, and Clinical Testing of a Novel Fastening Device for a Scoliosis Brace

Each year, thirty thousand children in the US were put into a scoliosis brace. The primary function of scoliosis braces was to reduce and prevent progression of the spinal deformity as the patient grew by application of corrective forces to the spine. Straps, often made of Velcro, were attached to the back of the brace that applied forces to the spine when the straps were tightened. Braces were prescribed to be worn up to 23 hours a day. Studies have concluded that discomfort increased with increasing strap tension and pad pressure. They have also shown an increase in strap tension occurred during deep breathing and some daily activities which led to discomfort. Consequently, discomfort often led to poor user compliance and reduced brace wear hence decreasing treatment efficacy. Treatment efficacy also decreased due to a loss of strap tension activities of lying down. The overall goals were to develop a novel fastening device, or controlled tension unit (CTU), for a scoliosis brace that allowed the user to set the strap tension to the prescribed value as determined by the orthotist at the time of brace fitting and to maintain the prescribed strap tension during a variety of typical daily living activities. This device should ensure the corrective force capacity of the scoliosis brace was present and the occurrence of strap loosening and tension loss was minimized. In the end, three studies were carried out to design and validate the CTU devices. For Study One, the objective was to determine the force-displacement properties of the controlled tension devices alone. The materials used were: Controlled Tension Units (CTU), Robotic Testing Platform. The methods were as follows: The controlled tension units were mounted in a robotic testing platform that was programmed to displace the CTU device at a set speed (or rate of spring displacement) and measure the force response of the device. Three different speeds and spring tensions were tested. The results were as follows: The CTU were designed with desired load settings of 20N, 30N, and 40N which were confirmed. The units applied a relatively constant tension over a working range of 12.7mm and maintained a load tolerance within ±10%. The force output response and load tolerances were independent of the rate of spring displacement. In conclusion, CTU devices could be fabricated with selectable load settings that held a relatively constant tension throughout a desired range of displacement. For Study Two, the first objective was to validate that the CTU force output was maintained over a finite amount of brace gap opening and closing (as it related to the brace gap separation). The second objective was to evaluate the corrective force capacity and structural stiffness properties of a standard 3-strap brace using either Velcro straps or CTU devices as the fastening system. The materials used were: Controlled Tension Units, Standard (Velcro Strap) Brace, Standard (CTU) Brace, Robotic Testing Platform, Scoliosis Analog Model (SAM), Lab Tensiometers. The methods were as follows: Three brace configurations were tested: Native Standard Brace, Standard (CTU) Brace, and Standard (Velcro Strap) Brace. A low tension CTU (≈20N) was used for all tests. Throughout the movement, the reaction forces and strap tensions in the craniocaudal and mediolateral axes were continuously recorded. The results were as follows: The CTU devices provided a greater range of brace gap displacement compared to the Velcro straps. For the CTU devices, the strap tension was constant over the range of displacement and remained close to the tension value of the CTU device (approximately 20N). However, the tensiometer readings were significantly greater with the Velcro straps being greatest at the top strap and lowest at the bottom. In conclusion, CTU devices could be used to develop a more flexible dynamic brace that allowed for directional movement without compromising the corrective force capacity of the brace. Contrary to the Velcro straps, the CTU strap tension setting would remain present independent of the brace gap allowing for opportunities of deep breathing, increased range of movement, and/or improved brace force correction. For Study Three, the objective was to determine if CTU reduced discomfort while maintaining a constant strap tension. The materials used were: Standard (Velcro Strap) Brace, Standard (CTU) Brace, Portable Tensiometers. The methods were as follows: The discomfort, strap tension, and gap distance were evaluated during typical daily activities as well as the range of motion where applicable using the Standard (Velcro Strap) Brace and the Standard (CTU) Brace. Afterwards, a CTU Increase Test was performed in which the tension in each CTU fastener was incrementally increased until the patient experienced a greater level of discomfort than with the Velcro strap condition at the prescribed tension. In conclusion, CTU improved bracing in scoliosis by maintaining strap tension, improving brace flexibility, decreasing discomfort at similar strap tensions, or by achieving higher strap tensions without increasing discomfort. In conclusion, the CTU devices allowed the user to set the strap tension to the prescribed value as determined by the orthotist at the time of brace fitting and maintained the prescribed strap tension during a variety of typical daily living activities to ensure the corrective force capacity of the scoliosis brace was present and the occurrence of strap loosening and tension loss was minimized

Light-activated modulation and coupling in integrated polymer-liquid crystal systems

We explore the transfer of an incident light pattern onto the liquid crystal (LC) bulk in a photorefractive cell through an integrated photoconducting layer that modulates the electric field applied to the device. The electrical properties and the strength of modulation are investigated as a function of the incident light intensity as well as the frequency and amplitude of the applied voltage, for two LCs with very different electrical conductivity. A simplified electrical model of the cell is proposed, demonstrating that the LC conductivity is a key factor determining the beam-coupling strength

TunIO: An AI-powered Framework for Optimizing HPC I/O

I/O operations are a known performance bottleneck of HPC applications. To achieve good performance, users often employ an iterative multistage tuning process to find an optimal I/O stack configuration. However, an I/O stack contains multiple layers, such as high-level I/O libraries, I/O middleware, and parallel file systems, and each layer has many parameters. These parameters and layers are entangled and influenced by each other. The tuning process is time-consuming and complex. In this work, we present TunIO, an AI-powered I/O tuning framework that implements several techniques to balance the tuning cost and performance gain, including tuning the high-impact parameters first. Furthermore, TunIO analyzes the application source code to extract its I/O kernel while retaining all statements necessary to perform I/O. It utilizes a smart selection of high-impact configuration parameters of the given tuning objective. Finally, it uses a novel Reinforcement Learning (RL)-driven early stopping mechanism to balance the cost and performance gain. Experimental results show that TunIO leads to a reduction of up to ≈73% in tuning time while achieving the same performance gain when compared to H5Tuner. It achieves a significant performance gain/cost of 208.4 MBps/min (I/O bandwidth for each minute spent in tuning) over existing approaches under our testing

The effect of variable oxygen impurities on microbial activity in conditions resembling geological storage sites

Current specifications on carbon dioxide (CO2) storage do not take into account the effect of oxygen (O2) present as an impurity, on storage site microbiology. Some microbiology related impacts related to the CCS process include the potential blockage of injection well, corrosion of pipes, oil souring and oil degradation. To investigate this, microcosm experiments were set up using the O2 concentrations of 0 ppm, 10 ppm, 100 ppm and atmospheric. Artificial groundwater and sandstone microcosms were inoculated with a mixed microbial community, incubated for 29 days and regularly sampled for gases produced and sampled at the end of the experiment to analyse the microbiology. Gas chromatography analysis of these microcosms showed no hydrogen sulphide (H2S) production and a variable amount of CO2 production. Microbial analysis of the microcosms show that the microbial inoculum (including sulphate reducing bacteria) was able to survive/grow better in the microcosms with 10 ppm and below compared to the higher levels of O2. The levels of CO2 for 100 ppm and atmospheric levels of O2 were similar indicating the introduction of 100 ppm of O2 could promote aerobic processes. This experiment has shown that small differences in O2 concentrations affects microbial communities relevant to geological storage sites which could cause operational issues. Further investigation is required to properly assess the effect of small O2 changes on H2S production

Significant changes in the skin microbiome mediated by the sport of roller derby

Diverse bacterial communities live on and in human skin. These complex communities vary by skin location on the body, over time, between individuals, and between geographic regions. Culture-based studies have shown that human to human and human to surface contact mediates the dispersal of pathogens, yet little is currently known about the drivers of bacterial community assembly patterns on human skin. We hypothesized that participation in a sport involving skin to skin contact would result in detectable shifts in skin bacterial community composition. We conducted a study during a flat track roller derby tournament, and found that teammates shared distinct skin microbial communities before and after playing against another team, but that opposing teams’ bacterial communities converged during the course of a roller derby bout. Our results are consistent with the hypothesis that the human skin microbiome shifts in composition during activities involving human to human contact, and that contact sports provide an ideal setting in which to evaluate dispersal of microorganisms between people

Acid-dissolution of antigorite, chrysotile and lizardite for ex situ carbon capture and storage by mineralisation

Serpentine minerals serve as a Mg donor in carbon capture and storage by mineralisation (CCSM). The acid-treatment of nine comprehensively-examined serpentine polymorphs and polytypes, and the subsequent microanalysis of their post-test residues highlighted several aspects of great importance to the choice of the optimal feed material for CCSM. Compelling evidence for the non-uniformity of serpentine mineral performance was revealed, and the following order of increasing Mg extraction efficiency after three hours of acid-leaching was established: Al-bearing polygonal serpentine (<5%) ≤ Al-bearing lizardite 1T (≈5%) < antigorite (24-29%) < well-ordered lizardite 2H1 (≈65%) ≤ Al-poor lizardite 1T (≈68%) < chrysotile (≈70%) < poorly-ordered lizardite 2H1 (≈80%) < nanotubular chrysotile (≈85%). It was recognised that the Mg extraction efficiency of the minerals depended greatly on the intrinsic properties of crystal structure, chemistry and rock microtexture. On this basis, antigorite and Al-bearing well-ordered lizardite were rejected as potential feedstock material whereas any chrysotile, non-aluminous, widely spaced lizardite and/or disordered serpentine were recommended. The formation of peripheral siliceous layers, tens of microns thick, was not universal and depended greatly upon the intrinsic microtexture of the leached particles. This study provides the first comprehensive investigation of nine, carefully-selected serpentine minerals, covering most varieties and polytypes, under the same experimental conditions. We focused on material characterisation and the identification of the intrinsic properties of the minerals that affect particle’s reactivity. It can therefore serve as a generic basis for any acid-based CCSM pre-treatment

Potential impacts of oxygen impurities in carbon capture and storage on microbial community composition and activity

Gaseous impurities, such as O2, are expected to be present within CO2 captured for storage. This could stimulate microbial activity in a geological CO2 storage site which has the potential to lead to operational issues such as injection well blockages, corrosion and oil souring. A series of experiments were carried out to examine the effect of 10 ppm and 100 ppm O2 in an anoxic (CO2 or N2) atmosphere on microbial communities and microbial gas production in laboratory scale experiments. Experiments inoculated with sulphate reducing bacteria enrichments were compared to uninoculated controls. The results show that H2S production is delayed in a CO2 atmosphere compared to the N2 atmosphere. 100 ppm O2 in CO2 resulted in a spike of H2S production as well as greater bacterial biomass when compared to the 10 ppm O2 in CO2 atmosphere. The inoculated N2 experiments showed similar patterns in H2S production and biomass regardless of O2 concentration. These results suggest that a concentration of O2 lower than 100 ppm in CO2 could reduce the potential for microbial growth and H2S production in CO2 storage sites. CH4 production was observed in some microcosms subsequent to H2S production, highlighting the potential for microbial methanogenesis in the in CCS reservoirs

Influence of biofilms on transport of fluids in subsurface granitic environments : some mineralogical and petrographical observations of materials from column experiments

Landfill and radioactive waste disposal risk assessments focus on contaminant transport and are principally concerned with understanding the movement of gas, water and solutes through engineered barriers and natural groundwater systems. However, microbiological activity can impact on transport processes changing the chemical and physical characteristics of the subsurface environment. Such effects are generally caused by biofilms attached to rock surfaces. This paper will present some mineralogical and petrographical observations of materials extracted at the completion of an experimental column study which examined the influences of biofilm growth on groundwater flow through crushed diorite from the Äspö Hard Rock Underground Research Laboratory, Sweden