There is evidence that appropriate footwear is an important factor in the prevention of foot pain in otherwise healthy people or foot ulcers in people with diabetes and peripheral neuropathy. A ...standard care for reducing forefoot plantar pressure is the utilization of orthotic devices such as total contact inserts (TCI) with therapeutic footwear. Most neuropathic ulcers occur under the metatarsal heads, and foot deformity combined with high localized plantar pressure, appear to be the most significant factors contributing to these ulcers. In this study, patient-specific finite element models of the second ray of the foot were developed to study the influence of TCI design on peak plantar pressure (PPP) under the metatarsal heads. A typical full contact insert was modified based on the results of finite element analyses, by inserting 4 mm diameter cylindrical plugs of softer material in the regions of high pressure. Validation of the numerical model was addressed by comparing the numerical results obtained by the finite element method with measured pressure distribution in the region of the metatarsal heads for a shoe and TCI condition. Two subjects, one with a history of forefoot pain and one with diabetes and peripheral neuropathy, were tested in the laboratory while wearing therapeutic shoes and customized inserts. The study showed that customized inserts with softer plugs distributed throughout the regions of high plantar pressure reduced the PPP over that of the TCI alone. This supports the outcome as predicted by the numerical model, without causing edge effects as reported by other investigators using different plug designs, and provides a greater degree of flexibility for customizing orthotic devices than current practice allows.
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CEKLJ, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, VSZLJ, ZAGLJ
This study took advantage of a unique opportunity to collect large sample sizes of a coral reef fish species across a range of physical and biological features of the Hawaiian Archipelago to ...investigate variability in the demography of an invasive predatory coral reef fish,
Cephalopholis argus
(Family: Epinephelidae). Age-based demographic analyses were conducted at 10 locations in the main Hawaiian Islands and estimates of weight-at-length, size-at-age, and longevity were compared among locations. Each metric differed among locations, although patterns were not consistent across metrics. Length-weight relationships for
C. argus
differed among locations and individuals weighed less at a given length at Hilo, the southernmost location studied. Longevity differed among and within islands and was greater at locations on Maui and Hawaii compared to the more northern locations on Oahu and Kauai. Within-island growth patterns differed at Kauai, Oahu, and Hawaii. This work provides a case study of fundamental life history information from distant and/or spatially limited locations that are critical for developing robust fishery models. The differences observed both among and within islands indicate that variability may be driven by cross-scale mechanisms that need to be considered in fisheries stock assessments and ecosystem-based management.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract Background Ground reaction forces from walking result in stress (pressure) and soft tissue strain at the plantar aspect of the foot. Excessive plantar pressure and tissue strain on the ...insensate foot may lead to ulceration. Our study investigated the effect of therapeutic footwear and custom-made orthotic inserts on pressure and tissue strain along the second ray of the plantar foot, and how these two variables are associated. Methods Twenty subjects (mean age 57.3 SD 9.3 years, 12 male, 8 female, body mass index 32.5 SD 7.4 kg/m2 ) with diabetes mellitus, peripheral neuropathy, and a history of a plantar ulcer participated. Plantar pressure data were recorded during computed tomography scans for four conditions (barefoot, shoe, shoe + total contact insert, and shoe + total contact insert + metatarsal pad). For each condition tested, tissue strain and plantar pressure were determined at the second metatarsal head and at 15 other points along the second ray. Findings Differences were noted between the 4 conditions for pressure ( P < 0.004) and soft tissue strain ( P < 0.042) at the second metatarsal head. Correlation coefficients demonstrated an association between pressure and strain (Barefoot r = 0.81, Shoe r = 0.75, Shoe + total contact insert r = 0.73, and Shoe + total contact insert + metatarsal pad r = 0.44). Interpretation Footwear and orthotic devices tested in this study decreased pressure and soft tissue strain at the second ray of the foot, and these two variables were strongly related. A better understanding of the role tissue strain plays in distributing plantar forces may lead to improvements in the design of orthotic devices.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background: Standard prevention and treatment strategies to decrease peak plantar pressure include a total contact insert with a metatarsal pad, but no clear guidelines exist to determine optimal ...placement of the pad with respect to the metatarsal head. The purpose of this study was to determine the effect of metatarsal pad location on peak plantar pressure in subjects with diabetes mellitus and peripheral neuropathy. Methods: Twenty subjects with diabetes mellitus, peripheral neuropathy, and a history of forefoot plantar ulcers were studied (12 men and eight women, mean age = 57 ± 9 years). CT determined the position of the metatarsal pad relative to metatarsal head and peak plantar pressures were measured on subjects in three footwear conditions: extra-depth shoes and a 1) total contact insert, 2) total contact insert and a proximal metatarsal pad, and 3) total contact insert and a distal metatarsal pad. The change in peak plantar pressure between shoe conditions was plotted and compared to metatarsal pad position relative to the second metatarsal head. Results: Compared to the total contact insert, all metatarsal pad placements between 6.1 mm to 10.6 mm proximal to the metatarsal head line resulted in a pressure reduction (average reduction = 32 ± 16%). Metatarsal pad placements between 1.8 mm distal and 6.1 mm proximal and between 10.6 mm proximal and 16.8 mm proximal to the metatarsal head line resulted in variable peak plantar pressure reduction (average reduction = 16 ± 21%). Peak plantar pressure increased when the metatarsal pad was located more than 1.8 mm distal to the metatarsal head line. Conclusions: Consistent peak plantar pressure reduction occurred when the metatarsal pad in this study was located between 6 to 11 mm proximal to the metatarsal head line. Pressure reduction lessened as the metatarsal pad moved outside of this range and actually increased if the pad was located too distal of this range. Computational models are needed to help predict optimal location of metatarsal pad with a variety of sizes, shapes, and material properties.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Mast-cell growth factor (MGF) is encoded by the murine steel (Sl) locus and is a ligand for the tyrosine kinase receptor protein encoded by the proto-oncogene c-kit at the murine dominant white ...spotting (W) locus. Mutations at both these loci affect mast cells, primordial germ cells (PGCs), haemopoietic stem cells and melanocytes. In many Sl and W mutants, the rapid proliferation of PGC that normally occurs between day 7 and 13.5 of embryonic development fails to occur. As c-kit is expressed in PGCs while MGF is expressed in the surrounding mesenchyme, MGF might promote the proliferation of PGCs. Here we report that MGF is essential for PGC survival in culture, but does not stimulate PGC proliferation. Moreover, whereas both the transmembrane and soluble proteolytic cleavage forms of MGF stimulate mast-cell proliferation, soluble MGF has a relatively limited ability to support survival of PGCs in culture, thus explaining the sterility in mice carrying the steel-dickie (Sld) mutation, which encodes only a soluble form of MGF, and providing a functional role for a transmembrane growth factor.
Much of coral reef ecology has focused on how human impacts change coral reefs to macroalgal reefs. However, macroalgae may not always be a good indicator of reef decline, especially on reefs with ...significant sea urchin populations, as found in Kenya and Hawaii. This study tests the effects of trophic interactions (i.e. herbivory by fishes and sea urchins) and spatial competition (between algae and coral) on algal community structure of reefs surrounding two Hawaiian Islands that vary in their level of human impacts. Reef‐building organisms (corals and crustose coralline algae) were less abundant and turf algae were more abundant on Maui as compared to Lanai, where human impacts are lower. In contrast to previous studies, we found no evidence that macroalgae increased with human impacts. Instead, low turf and macroalgal abundance were best explained by the interactive effects of coral cover and sea urchin abundance. Fishing sea urchin predators appeared to have cascading effects on the benthic community. The absence of sea urchin predators and high sea urchin densities correspond to a disproportionately high abundance of turf and crustose coralline algae. We propose that high turf algal abundance is a better indicator of reef decline in Hawaii than high macroalgal abundance because turf abundance was highest on reefs with low coral cover and few fish. The results of this study emphasize that understanding changes in community composition are context‐dependent and that not all degraded reefs look the same.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Conservation of ecological communities requires deepening our understanding of genetic diversity patterns and drivers at community-wide scales. Here, we use seascape genetic analysis of a diversity ...metric, allelic richness (AR), for 47 reef species sampled across 13 Hawaiian Islands to empirically demonstrate that large reefs high in coral cover harbour the greatest genetic diversity on average. We found that a species's life history (e.g. depth range and herbivory) mediates response of genetic diversity to seascape drivers in logical ways. Furthermore, a metric of combined multi-species AR showed strong coupling to species richness and habitat area, quality and stability that few species showed individually. We hypothesize that macro-ecological forces and species interactions, by mediating species turnover and occupancy (and thus a site's mean effective population size), influence the aggregate genetic diversity of a site, potentially allowing it to behave as an apparent emergent trait that is shaped by the dominant seascape drivers. The results highlight inherent feedbacks between ecology and genetics, raise concern that genetic resilience of entire reef communities is compromised by factors that reduce coral cover or available habitat, including thermal stress, and provide a foundation for new strategies for monitoring and preserving biodiversity of entire reef ecosystems.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Bonefishes are a cryptic species complex that are a prized sportfish in many places around the world. In Hawai‘i they have a long history of use and today have important recreational, and cultural ...value. In the early 1980s, two distinct species of bonefishes were determined to inhabit Hawaiian waters (
Albula glossodonta
“round jaw”, and
A. virgata
“sharp jaw”). Little is known about the life histories of these two species, hindering population assessments and relevant fisheries management guidelines. In addition, no ecological studies have been conducted to examine interactions or separation between these species. This research assesses how differences in size, abundance, diet, growth, reproduction, and habitat preference of the two bonefish species in Hawai‘i can explain the coexistence and persistence of these two closely related species. Differences in size structure, growth rates, and spawning patterns for each species provides species-specific life history information that differentiates them ecologically and is useful for population assessments and in developing species-specific management strategies. We found that the wide-ranging species,
A. glossodonta
had a larger mean size, length at a given weight, and size at maturity than the endemic,
A. virgata
. We found differences in prey preferences between the two species that support our hypothesis that differences in jaw morphologies and habitat preferences translate to dissimilarities in diet. This study contributes to our knowledge about these species and provides an example of niche specialization in two closely related and cohabiting species.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Coral reefs worldwide face unprecedented cumulative anthropogenic effects of interacting local human pressures, global climate change and distal social processes. Reefs are also bound by the natural ...biophysical environment within which they exist. In this context, a key challenge for effective management is understanding how anthropogenic and biophysical conditions interact to drive distinct coral reef configurations. Here, we use machine learning to conduct explanatory predictions on reef ecosystems defined by both fish and benthic communities. Drawing on the most spatially extensive dataset available across the Hawaiian archipelago—20 anthropogenic and biophysical predictors over 620 survey sites—we model the occurrence of four distinct reef regimes and provide a novel approach to quantify the relative influence of human and environmental variables in shaping reef ecosystems. Our findings highlight the nuances of what underpins different coral reef regimes, the overwhelming importance of biophysical predictors and how a reef’s natural setting may either expand or narrow the opportunity space for management interventions. The methods developed through this study can help inform reef practitioners and hold promises for replication across a broad range of ecosystems.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Invasive species are a growing concern for marine biodiversity, particularly in Hawai‘i with its large proportion of endemic species. This research focused on the feasibility of removing the ...introduced predatory peacock grouper Cephalopholis argus, locally known as roi, as a management tool for Hawaiian coral reef ecosystem restoration. The objectives of this study were to investigate the dynamics of C. argus on 1.3 hectares (ha) of coral reef at Puakō, Hawai‘i, and to (1) compare population density estimate methods in order to accurately evaluate abundance, (2) estimate population mortality and catchability rates, and (3) quantify the re-colonization rates by mapping distribution and movements in response to a depletion experiment. The number of individuals removed during a fish-down experiment provided a direct measure of initial population abundance (20.2 roi ha−1). A Leslie depletion model yielded the most accurate assessment of initial density (−15.8% error) compared to belt transects (+75.7% error) and tow-board census (−70.2% error). Estimates of total mortality were low (0.12 to 0.14), and fishing mortality ranged from negligible to 8.0% yr−1 in west Hawai‘i. Roi movement was monitored through a mark and re-capture program. Tagged individuals traveled 50 to 150 m from the periphery toward the center of the removal area (1 roi every 1 to 2 mo). This study engaged the local Hawaiian fishing community in assessing and managing marine invasive fish species, quantified the feasibility of roi removal as an ecosystem management tool, and provides evidence for effective roi population control through spear-fishing methods at the local (1.3 ha) patch-reef scale.
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