Publications by authors named "David Kingston"

Background: The Gait Deviation Index (GDI) is a metric clinicians use to assess overall gait pathology in children with cerebral palsy (CP) by comparing kinematic data to a normative sample. The Gait Variability Index (GVI) is a related metric that quantifies the variability in spatio-temporal variables during gait. The GDI and GVI have been verified using marker-based motion capture approaches, but video-based markerless motion capture has not been compared using these tools in children with CP.

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Background: Individuals who are living with obesity often adopt alternative lower limb walking mechanics compared to persons with a healthy weight. Stair negotiation is a common activity of daily living that, when used consistently with diet and other physical activity, can help promote the reversal of health-related risk factors associated with people who are obese. The purpose of this study was to determine how stair negotiation affects normalized and non-normalized peak knee extension and abduction moments in young adults who live with obesity (BMI between 30 and 40 kg/m) compared to adults with a healthy weight (BMI between 18.

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Background: Diabetic patients with foot ulcers are commonly prescribed assistive walking devices to unload the affected foot and promote tissue healing. However, the effect on shear loads to the contralateral foot is unknown. This study investigated the effect of a wheeled knee walker (WKW), compared to common devices, on compressive and shear plantar forces carried by the propulsive foot during walking in patients with type 2 diabetes mellitus.

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Treadmill-based gait rehabilitation protocols have shown that real-time visual biofeedback can promote learning of improved gait biomechanics, but previous feedback work has largely involved treadmill walking and not overground gait. The objective of this study was to determine the short-term response to hip extension visual biofeedback, with individuals post-stroke, during unconstrained overground walking. Individuals post-stroke typically have a decreased paretic propulsion and walking speed, but increasing hip extension angle may enable the paretic leg to better translate force anteriorly during push-off.

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Background: Patients suffering from a diabetic foot ulcer often receive a non-weight bearing prescription of the affected limb to promote healing. Total unilalteral offloading of the affected foot necessitates walking aids that require loading at the hands during ambulation. Excessive loading at the hands can increase of the risk of crutch palsy.

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Background: Visual biofeedback has shown success in improving gait mechanics in individuals post-stroke but has typically been restricted to use on a treadmill or a short walkway. Using real-time visual biofeedback during overground walking could increase the ease of clinical translation of this method. The objective was to investigate the reliability of a real-time hip extension feedback device during unconstrained, overground walking.

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Background: Three-dimensional (3D) motion analysis is an advanced tool used to quantify movement patterns in adults with chronic stroke and children with cerebral palsy. However, gold-standard marker-based systems have limitations for implementation in clinical settings. Markerless motion capture using may provide a more accessible and clinically feasible alternative, but its accuracy is unknown in clinical populations.

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Aquatic treadmill gait training is a poorly understood rehabilitation method that alters bodyweight support, increases lower limb resistance, and assists with postural stability. This training could be an attractive tool for clinical populations with balance control issues or limited weight-bearing prescriptions for the lower limb. As a first step, the purpose of this study was to quantify differences in mean muscle activity of the tibialis anterior, rectus femoris, medial gastrocnemius, and semitendinosus, and perceived exertion (RPE) in typically developing children (7:8 M:F, age = 11.

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Phytochemical investigation of the methanol extract of the fruit rind of Myristica malabarica led to the isolation of eight known compounds that were identified as malabaricones A-D, promalabaricones B and C, 1-(2,6-dihydroxyphenyl)tetradecan-1-one, and ericanone by comparison with literature spectroscopic data. The structures of malabaricones A-D, promalabaricone B, and 1-(2,6-dihydroxyphenyl)tetradecan-1-one were confirmed by X-ray crystallography. In vitro assay of the isolated phenols indicated that they exhibited moderate anti-proliferative activity against the A2780 human ovarian cancer cell.

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Aims: Patients with diabetic foot ulcers are instructed to be non-weight bearing on the affected limb to promote healing. Therefore, the aim of this study was to investigate the effect of different assistive devices on whole foot plantar loading, peak forefoot force, ankle range of motion, and locomotion speed during gait in patients with Type 2 Diabetes Mellitus.

Methods: Participants walked normally, with crutches, a walker, and a wheeled knee walker (WKW) in randomized order.

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Metal leachate from mine tailings has the potential to release toxic metals into the surrounding environment. A single-step extraction procedure mimicking rainwater and a three-step BCR sequential extraction procedure (acid, reducing and oxidizing conditions) were applied to gold (GMT) and silver (SMT) mine tailings. Major (Al, Ca, Fe, Mg, and Mn) and trace metals were monitored to better understand the mobility and geochemistry of these metals when exposed to various environmental leaching conditions.

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Background: Young adults often tolerate the increased energy expenditure, coordination, and stance limb discomfort associated with walking aids for nonweightbearing ambulation. Adults aged ≥50 years may not have the same tolerance. Therefore, the objective of this study was to determine how walking aid selection affects stance limb plantar force, walking speed, perceived exertion, and device preference in adults aged ≥50 years.

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Natural products have made a crucial and unique contribution to human health, and this is especially true in the case of malaria, where the natural products quinine and artemisinin and their derivatives and analogues, have saved millions of lives. The need for new drugs to treat malaria is still urgent, since the most dangerous malaria parasite, Plasmodium falciparum, has become resistant to quinine and most of its derivatives and is becoming resistant to artemisinin and its derivatives. This volume begins with a short history of malaria and follows this with a summary of its biology.

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Eight phloroglucinols from were recently reported to have good to moderate antiplasmodial and anticancer activities, consistent with other phloroglucinol derivatives isolated from natural sources. Chiroptical properties were previously calculated and compared to experimental data for compound as a means to deduce its absolute configuration. Tentative assignments for the remaining compounds were also reported based on these data.

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Movement pattern differences may contribute to differential injury or disease prevalence between individuals. The purpose of this study was to identify lower limb movement patterns in high knee flexion, a risk factor for knee osteoarthritis, and to investigate kinematic differences between males and females, as females typically develop knee osteoarthritis more commonly and severely than males. Lower extremity kinematic data were recorded from 110 participants completing 4 variations of squatting and kneeling.

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The author describes his 60-year career in studying the chemistry of natural products, which includes structural, synthetic, and biosynthetic studies of natural products ranging from insect pigments, antibiotics, and fecal mutagens to taxol and other anticancer natural products as well as antimalarial natural products. One of the compounds discussed, napabucasin, is now an anticancer drug in phase III clinical trials.

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Minimal footwear has become more ubiquitous; however, it may increase slip severity. This study specifically examined the slipping kinematics of flip-flop sandals. Invoked slips from standing were evaluated in dry and wet tile, and a unique wet footbed + wet tile condition, with 40, 50, and 60% bodyweight (BW) committed to the slipping foot.

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The BCR sequential extraction procedure developed by the European Community Bureau of Reference was applied to the three marine sediment certified reference materials (CRMs). These CRMs are designated as HISS-1, MESS-4, and PACS-3 and comprise respectively pristine, moderately-contaminated, and highly-contaminated sediments, respectively. The study aimed to provide values of extractable elements in reference materials of varied geological origin to support method development and quality control efforts.

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A musculoskeletal model of the right lower limb was developed to estimate 3D tibial contact forces in high knee flexion postures. This model determined the effect of intersegmental contact between thigh-calf and heel-gluteal structures on tibial contact forces. This model includes direct tracking and 3D orientation of intersegmental contact force, femoral translations from in vivo studies, wrapping of knee extensor musculature, and a novel optimization constraint for multielement muscle groups.

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Background: Mobility aids are commonly prescribed to offload an injured lower extremity. Device selection may impact stance foot loading patterns and foot health in clinical populations at risk of foot ulceration.

Research Questions: Two questions motivated this study: How does device selection influence peak plantar and regional (rearfoot, mid foot and forefoot) foot forces on the stance foot? Does device selection influence peak, cumulative, and regional plantar forces within a 200 m walking trial?

Methods: Twenty-one older adults walked 200 m at self-selected pace in four randomized conditions for this prospective crossover study.

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Chromatographic separation of the acetone extracts from the twigs and barks of Artocarpus lakoocha led to the isolation of the one new flavanone, lakoochanone (1), together with eleven known compounds (2-12). Lakoochanone (1) and moracin C (4) exhibited weak antiplasmodial activity against Plasmodium falciparum Dd2 with IC values of 36.7 and 33.

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Article Synopsis
  • Vitex rotundifolia is a medicinal plant used in traditional medicine for treating various health issues, but its potential against malaria hasn't been studied before.
  • Research identified three new and five known diterpenoids from the plant using advanced purification and structural analysis methods.
  • The purified compounds showed promising in vitro activity against the malaria parasite Plasmodium falciparum, with compounds 2, 6, and 8 having notable inhibitory concentrations.
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An extract of from the Natural Products Discovery Institute showed moderate antiplasmodial activity, with an IC value less than 1.25 μg/mL. The two known cholestane glycosides and and the five new cholestane glycosides galtonosides A-E (-) were isolated after bioassay-directed fractionation.

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New Findings: What is the central question of this study? Does smartly timed intermittent compression of the lower legs alter cerebral blood velocity and oxygenation during acute orthostatic challenges? What is the main finding and its importance? Intermittent compression timed to the local diastolic phase increased the blood flux through the legs and heart after two different orthostatic stress tests. Cerebral blood velocity improved during the first minute of recovery, and indices of cerebral tissue oxygenation remained elevated for 2 min. These results provide promise for the use of lower-leg active compression as a therapeutic tool for individuals vulnerable to initial orthostatic hypotension and orthostatic stress.

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