Publications by authors named "Elzinga M"

Stimulated by the desire to achieve a Net Zero energy economy, the demand for renewable fuels is growing rapidly. The production of toxic waste streams that accompanies the transition from fossil fuels to renewable fuels is often overlooked. These waste streams include, among others, thiols and ammonia, and benzene, toluene, and xylene (BTX).

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The measurement of VOSCs in complex matrices is challenging due to their volatile and reactive nature. A straightforward method using headspace chromatography was developed for routine analyses of organosulfur compounds in a high saline liquid matrix with a pH of 8.4.

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Study Design: Systematic review.

Objective: In 1994, the Load Sharing Classification (LSC) was introduced to aid the choice of surgical treatment of thoracolumbar spine fractures. Since that time this classification system has been commonly used in the field of spine surgery.

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Organosulfur compounds, present in e.g. the pulp and paper industry, biogas and natural gas, need to be removed as they potentially affect human health and harm the environment.

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Introduction: The British Orthopedic Association (BOA) and British Association of Plastic, Reconstructive and Aesthetic Surgeons (BAPRAS) updated the evidence-based guidelines for the treatment and care of open lower limb fractures (BOAST 4). Following this, a Dutch version has been developed. The main points are multidisciplinary care, planning, and treatment of these injuries.

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Using high-speed videography, we investigated how fruit flies compensate for unilateral wing damage, in which loss of area on one wing compromises both weight support and roll torque equilibrium. Our results show that flies control for unilateral damage by rolling their body towards the damaged wing and by adjusting the kinematics of both the intact and damaged wings. To compensate for the reduction in vertical lift force due to damage, flies elevate wingbeat frequency.

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The flight pattern of many fly species consists of straight flight segments interspersed with rapid turns called body saccades, a strategy that is thought to minimize motion blur. We analyzed the body saccades of fruit flies (Drosophila hydei), using high-speed 3D videography to track body and wing kinematics and a dynamically scaled robot to study the production of aerodynamic forces and moments. Although the size, degree and speed of the saccades vary, the dynamics of the maneuver are remarkably stereotypic.

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The ability to regulate forward speed is an essential requirement for flying animals. Here, we use a dynamically-scaled robot to study how flapping insects adjust their wing kinematics to regulate and stabilize forward flight. The results suggest that the steady-state lift and thrust requirements at different speeds may be accomplished with quite subtle changes in hovering kinematics, and that these adjustments act primarily by altering the pitch moment.

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Avoiding predators is an essential behavior in which animals must quickly transform sensory cues into evasive actions. Sensory reflexes are particularly fast in flying insects such as flies, but the means by which they evade aerial predators is not known. Using high-speed videography and automated tracking of flies in combination with aerodynamic measurements on flapping robots, we show that flying flies react to looming stimuli with directed banked turns.

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In closed-loop systems, sensor feedback delays may have disastrous implications for performance and stability. Flies have evolved multiple specializations to reduce this latency, but the fastest feedback during flight involves a delay that is still significant on the timescale of body dynamics. We explored the effect of sensor delay on flight stability and performance for yaw turns using a dynamically scaled robotic model of the fruitfly, Drosophila.

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The Load Sharing Classification (LSC) allocates one to three points to each of three different radiological characteristics of traumatic thoracolumbar fractures: the vertebral body involved in the fracture, the displacement of the fracture parts and the kyphotic deformity. Added up, a minimal score of three and a maximal score of nine can be obtained. When the LSC score is three to six, a short segment pedicle screw fixation suffices.

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The Roland Morris Disability Questionnaire (RMDQ-24) and the VAS spine score have been regularly used to measure functional outcome in patients with back pain. The RMDQ-24 is primarily used in degenerative disease of the spine and the VAS Spine is used in trauma patients. The aim of this study is to compare these scores and to see if there is a correlation in patients with a traumatic thoracolumbar spinal fracture.

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This paper discusses the role of knee positioning and range-of- motion on the closed-stance forehand tennis swing. The analyses of tennis swing mechanics were performed using a computer model comprised of a full-body model of a human and an inertial model of a racket. The model was driven by subject forehand swings (16 female college-level subjects) recorded with a high-speed digital motion analysis system.

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Background: Spinal fractures can be an important cause for disabling back pain. Therefore, in judging the cost-effectiveness of nonsurgical or surgical therapy, not only direct costs but also the indirect costs should be calculated. In this prospective randomized study, the costs incurred by nonsurgically and surgically treated patients with a traumatic thoracolumbar spine fracture without neurological involvement were analysed.

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Study Design: Multicenter prospective randomized trial.

Objective: To test the hypotheses that thoracolumbar AO Type A spine fractures without neurologic deficit, managed with short-segment posterior stabilization will show an improved radiographic outcome and at least the same functional outcome as compared with nonsurgically treated thoracolumbar fractures.

Summary Of Background Data: There are various opinions regarding the ideal management of thoracolumbar Type A spine fractures without neurologic deficit.

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Study Design: Retrospective study and review of literature.

Objectives: Study of demographic data concerning spinal fractures caused by horse riding, classification of fractures according to the AO and Load Sharing classifications, evaluation of mid-term radiological results and long-term functional results.

Methods: A review of medical reports and radiological examinations of patients presented to our hospital with horse riding-related spine fractures over a 13-year period; long-term functional follow-up is performed using the Roland Morris Disability Questionnaire (RMDQ-24).

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This paper discusses the inertia tensors of tennis rackets and their influence on the elbow swing torques in a forehand motion, the loadings transmitted to the elbow from central and eccentric impacts, and the racket acceleration responses from central and eccentric impacts. Inertia tensors of various rackets with similar mass and mass center location were determined by an inertia pendulum and were found to vary considerably in all three orthogonal directions. Tennis swing mechanics and impact analyses were performed using a computer model comprised of a full-body model of a human, a parametric model of the racket, and an impact function.

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We investigated the effects of low frequency fatigue (LFF) on post-exercise changes in rectified surface EMG (rsEMG) and single motor unit EMG (smuEMG) in vastus lateralis muscle (n = 9). On two experimental days the knee extensors were fatigued with a 60-s-isometric contraction (exercise) at 50% maximal force capacity (MFC). On the first day post-exercise (15 s, 3, 9, 15, 21 and 27 min) rsEMG and electrically-induced (surface stimulation) forces were investigated.

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The effect on drag of a Speedo Fast-skin suit compared to a conventional suit was studied in 13 subjects (6 males, 7 females) swimming at different velocities between 1.0 and 2.0 m.

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The purpose of the present study was to relate the expected inter-subject variability in voluntary drive of the knee extensor muscles during a sustained isometric contraction to the changes in firing rates of single motor units. Voluntary activation, as established with superimposed electrical stimulation was high (range: 91-99%, n=8) during a short maximal contraction, but was lower (range: 69-100%) in most subjects at the point of force failure during a sustained (49.1+/-10.

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The minibrain kinase (Mnbk)/dual specificity Yak 1-related kinase 1A (Dyrk1A) gene is implicated in the mental retardation associated with Down's syndrome. It encodes a proline-directed serine/threonine kinase whose function has yet to be defined. We have used a solid-phase Mnbk/Dyrk1A kinase assay to aid in the search for the cellular Mnbk/Dyrk1A substrates.

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A new heterobifunctional photo-cross-linking reagent, N-(4-azido-2-nitrophenyl)-putrescine (ANP), was synthesized and covalently bound to Gln-41 of rabbit skeletal muscle actin by a bacterial transglutaminase-mediated reaction. Up to 1.0 mol of the reagent was incorporated per mole of G-actin; at least 90% of it was bound to Gln-41 while a minor fraction (about 8%) was attached to Gln-59.

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During the course of the expression of a 47-kDa COOH-terminal fragment of brain-type nonmuscle myosin heavy chain (MIIBF47), we found two closely related forms of MIIB, designated MIIB alpha and MIIB beta, in rabbit brains. The B alpha form corresponded to SMemb, described by Kuro-o et al. [(1991) J.

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The beta-thymosins are a family of highly polar peptides which serve in vivo to maintain a reservoir of unpolymerized actin monomers. In vitro, beta-thymosins form 1:1 complexes with actin monomers and inhibit both polymerization and exchange of the bound nucleotide. Circular dichroism data indicate that free thymosin beta 4 is predominantly unstructured, containing at most six residues of alpha-helix, and that up to six additional residues may adopt an alpha-helical conformation upon binding actin.

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Phosphoinositides bind to profilin and regulate actin-based cytoskeletal protein assembly. We report here that profilin is phosphorylated in vitro by protein kinase C (PKC) in the presence of phosphoinositides and micromolar concentrations of calcium. PKC-mediated phosphorylation of profilin was observed only in the presence of phosphoinositides; phosphatidylserine and diacylglycerol (known activators of PKC) and other lipids, including phosphatidic acid and phosphatidylglycerol phosphate, did not activate the phosphorylation.

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