Surface Area For Attachment Research Articles

Modification and Performance of a Rotating Biological Contactor for the Rectification of Synthetic Auramine O dye Wastewater

The disposal of domestic and industrial wastewater into the drainage/atmosphere without treatment is a major source of pollution that endangers the health of the population and needs to be controlled. Despite long been used as a secondary treatment strategy for wastewater, conventional rotating biological contactor (RBC) suffers from the drawbacks of limited surface area for the growth of biofilms. There are persistent problems of less oxygenation capacity, and inefficient mixing resulting in inadequate mass transfer. To address these issues conventional RBC has been modified in the present study by replacing a bank of discs using a rotating drum. The use of a rotating drum in RBC enhanced the biofilm attachment surface area up to 2.29 m2 (?108.2% higher than conventional RBC), thereby improving the working performance. To prevent the dissolved oxygen as a limiting factor, four small aerators were placed as supplement aeration system in the wastewater collection tank of modified RBC. To prevent the influence of atmospheric temperature on biological process, a blast-proof aquarium glass heater was placed in the tank. For experimental work, a 700 ppm pretreated synthetic solution of Auramine-O dye as wastewater was utilized. A constant level of percentage variation in biological oxygen demand (BOD) removal efficiency was observed after 15 days of the experiment. After day-15, the MLSS concentration increased to 2960 mg/L, and the BOD concentration reduced to 12.85 mg/L, resulting in a reduction of 89.86% in BOD, indicating the meeting of effluent discharge standards.

Enhanced refractive index sensing using a surface plasmon resonance sensor with heterostructure

This article aims to enhance the sensitivity of a surface plasmon resonance sensor for refractive index sensing in the visible region using a low refractive index prism. The proposed sensing system is ultrasensitive and employs an angular interrogation method for measuring reflected intensity. The bimetallic layers and two-dimensional heterostructure are utilized to increase sensitivity. Black phosphorus is utilized as an analyte-interacting layer due to its sp3 hybridized puckered structure, high charge carrier density, indirect bandgap and larger surface area for attachment of analyte. To optimize the sensor structure and architecture based on its sensitivity and figure of merit, a comprehensive analysis is performed. The proposed sensor achieves the best possible sensitivity of 345.83°/RIU, detection accuracy of 0.132 Deg−1 and figure of merit of 45.74/RIU. This work enables to design a highly sensitive refractive index sensor useful to sense small sized analyte. The proposed research work provides new dimension to develop highly sensitive refractive index sensor for biomolecule or biochemical sensing.

A novel SiO2–ZnS-Am-TiO2/PbS–CdS@ZnO-NRs/FTO photoanode based quantum dots sensitized solar cell

In this study, a novel and cost-effective design of a solar cell was introduced that utilized array of Zinc Oxide (ZnO) nanorods sensitized with Lead Sulfide (PbS) and Cadmium Sulfide (CdS) quantum dots (QDs). Three devices of the proposed solar cell architecture were fabricated using Fluorine-doped Tin Oxide (FTO) coated glass as a substrate and varying numbers of successive ionic layer adsorption and reaction (SILAR) cycles (10, 15, and 20) for PbS/CdS QDs sensitization. Three additional layers (Amorphous TiO2, ZnS, SiO2) were added to prevent charge recombination and ensure efficient charge transfer. The ZnO nanorods were formed and confirmed by scanning electron microscopy (SEM) analysis, which revealed that the relatively dense packing density of nanorods provided an adequate surface area for attachment of the PbS/CdS QDs. The optical properties of the solar cells were studied using UV–Visible spectroscopy, which showed that the optical absorption increased with an increase in the number of SILAR cycles. The proposed solar cell architecture exhibited a remarkable power conversion efficiency of 5.12%, which was attributed to the synergistic effects of the ZnO nanorods and PbS/CdS QDs. The unique design of solar cells with additional passivation layers makes it highly efficient, cost-effective, and easy to fabricate. Moreover, the use of readily available materials and the simplicity of the fabrication process make it a promising candidate for large-scale photovoltaic applications. Maximum efficiency of 5.12% was obtained. The finding of this study confirms that the proposed novel architecture can be a promising solar cell.

Anatomical Study of Sites and Surface Area of the Attachment Region of Tibial Posterior Tendon Attachment.

The purpose of this study was not only to examine the attachment site but also to quantify the effect of the tibialis posterior tendon (TPT) on each attachment site by examining the surface area of the attachment region. We examined 100 feet from 50 Japanese cadavers. The TPT attachment to the navicular bone (NB), medial cuneiform bone (MCB), and lateral cuneiform bone (LCB) were set as the main attachment sites (Type I). The attachment seen in Type I with the addition of one additional site of attachment was defined as Type II. Furthermore, surface area was measured using a three-dimensional scanner. Attachment to the NB, MCB, and LCB was present in all specimens. The TPT attachment to the NB, MCB, and LCB comprised 75.1% of total attachment surface area. The ratio of the NB, MCB, and LCB in each type was about 90% in Types II and III, and 70-80% in Types IV-VII. The quantitative results demonstrated the NB, MCB, and LCB to be the main sites of TPT attachment, although individual differences in attachment sites exist, further developing the findings of previous studies.

Repeated Administration of Cisplatin Transforms Kidney Fibroblasts through G2/M Arrest and Cellular Senescence.

Cisplatin is a potent chemotherapeutic used for the treatment of many types of cancer, but it has nephrotoxic side effects leading to acute kidney injury and subsequently chronic kidney disease (CKD). Previous work has focused on acute kidney tubular injury induced by cisplatin, whereas the chronic sequelae post-injury has not been well-explored. In the present study, we established a kidney fibroblast model of CKD induced by repeated administration of cisplatin (RAC) as a clinically relevant model. In NRK-49F rat kidney fibroblasts, RAC upregulated α-smooth muscle actin (α-SMA) and fibronectin proteins, suggesting that RAC induces kidney fibroblast-to-myofibroblast transformation. RAC also enhanced cell size, including the cell attachment surface area, nuclear area, and cell volume. Furthermore, RAC induced p21 expression and senescence-associated β-galactosidase activity, suggesting that kidney fibroblasts exposed to RAC develop a senescent phenotype. Inhibition of p21 reduced cellular senescence, hypertrophy, and myofibroblast transformation induced by RAC. Intriguingly, after RAC, kidney fibroblasts were arrested at the G2/M phase. Repeated treatment with paclitaxel as an inducer of G2/M arrest upregulated p21, α-SMA, and fibronectin in the kidney fibroblasts. Taken together, these data suggest that RAC transforms kidney fibroblasts into myofibroblasts through G2/M arrest and cellular senescence.

Challenges and opportunities in downstream separation processes for mesenchymal stromal cells cultured in microcarrier-based stirred suspension bioreactors.

Mesenchymal stromal cells (MSC) are a promising platform for regenerative medicine applications because of their multilineage differentiation abilities and ease of collection, isolation, and growth ex vivo. To meet the demand for clinical applications, large-scale manufacturing will be required using three-dimensional culture platforms in vessels such as stirred suspension bioreactors. As MSCs are an adherent cell type, microcarriers are added to the culture to increase the available surface area for attachment and growth. Although extensive research has been performed on efficiently culturing MSCs using microcarriers, challenges persist in downstream processing, including harvesting, filtration, and volume reduction, which all play a critical role in the translation of cell therapies to the clinic. The objective of this review is to assess the current state of downstream technologies available for microcarrier-based MSC cultures. This includes a review of current research within the three stages: harvesting, filtration, and volume reduction. Using this information, a downstream process for MSCs is proposed, which can be applied to a wide range of applications.

Effect of dispersants on bacterial colonization of oil droplets: A microfluidic approach

Bacteria biodegradation of immiscible oil requires cell-droplet encounters, surface attachment, and hydrocarbon metabolism. Chemical dispersants are applied to oil spills to reduce the mean dispersed droplet size, thereby increasing the available surface area for attachment, in attempts to facilitate bacterial biodegradation. However, their effectiveness remains contentious as studies have shown that dispersants can inhibit, enhance, or have no effect on biodegradation. Therefore, questions remain on whether dispersants affect surface attachment or cell viability. Here, using microfluidics and time-lapse microscopy, we directly observe the attachment and growth of the marine bacterium, Alcanivorax borkumensis, on stationary crude oil droplets (5 μm <R < 150 μm) in the presence of Corexit 9500. We show that the average colonization time, or the time comprised of encounters, attachment, and growth, is dependent on droplet size and primarily driven by diffusive encounters. Our results suggest that dispersants do not inhibit or enhance these biophysical processes.

Improved performance and cost efficiency by surface area optimization of granular activated carbon in air-cathode microbial fuel cell

Microbial fuel cell (MFC) architectural modification is increasingly becoming an important area of research due to the need to improve energy recovery. This study presents a low-cost modification method of the anode that does not require pre-treatment-step involving hazardous chemicals to improve performance. The modification step involves deposition of granular activated carbon (GAC) which is highly conductive and provides a high specific surface area inside a carbon cloth that acts as an anode and as a supporting material. The GAC particle size of 0.6–1.1 mm resulted in an increase in air-cathode MFC performance due to an increase in available surface area of 879.5 m2 g−1 for attachment of cells based on Brunauer, Emmett, and Teller (BET) results, and an increase in the appropriate surface for attachment of cells which was rough based on the scanning electron microscope (SEM) results. On the other hand, although GAC with size of particles of 0.45–0.6 mm had the highest available surface area for attachment of cells, it lacked the appropriate surface for attachment of cells and reduced MFC performance. This means that particle size optimization of GAC is essential since there is a limit to which the particle diameter can be reduced. The utilization of the GAC with the optimized particle size produced an output voltage of 507.5 mV and maximum power output of 1287.7 mW m−3 at current output of 2537.5 mA m−3. This study also showed that there is an economic benefit in modifying carbon cloth using GAC with optimized particle size.

Micro computed tomography with and without contrast enhancement for the characterization of microcarriers in dry and wet state

In the field of regenerative medicine, microcarriers are used as support matrix for the growth of adherent cells. They are increasingly recognised as promising biomaterials for large scale, cost-effective cell expansion bioreactor processes. However, their individual morphologies can be highly heterogeneous which increases bioprocesses’ variability. Additionally, only limited information is available on the microcarriers’ 3D morphology and how it affects cell proliferation. Most imaging modalities do not provide sufficient 3D information or have a too limited field of view to appropriately study the 3D morphology. While microfocus X-ray computed tomography (microCT) could be appropriate, many microcarriers are hydrated before in-vitro use. This wet state makes them swell, changing considerably their morphology and making them indistinguishable from the culture solution in regular microCT images due to their physical density close to water. The use of contrast-enhanced microCT (CE-CT) has been recently reported for 3D imaging of soft materials. In this study, we selected a range of commercially available microcarrier types and used a combination of microCT and CE-CT for full 3D morphological characterization of large numbers of microcarriers, both in their dry and wet state. With in-house developed image processing and analysis tools, morphometrics of individual microcarriers were collected. Also, the morphology in wet state was assessed and related to accessible attachment surface area as a function of cell size. The morphological information on all microcarriers was collected in a publicly available database. This work provides a quantitative basis for optimization and modelling of microcarrier based cell expansion processes.

Cling performance and surface area of attachment in plethodontid salamanders.

Plethodontid salamanders inhabit terrestrial, scansorial, arboreal and troglodytic habitats in which clinging and climbing allow them to access additional food and shelter as well as escape from unfavorable temperature and moisture conditions and ground-dwelling predators. Although salamanders lack claws and toe pads found in other taxa, they successfully cling to and climb on inclined, vertical and inverted substrates in nature. Maximum cling angle was tested on smooth acrylic, and the relationship between cling angle, body mass and surface area of attachment (contact area) was investigated. This study found that many salamander species can cling fully inverted using only a portion of their ventral surface area to attach. Salamanders fall into three functional groups based on mass and maximum cling angle: (1) high-performing, very small salamanders, (2) moderately high performing small and medium-sized salamanders and (3) low-performing large salamanders. They show significant differences in maximum cling angle, even between species of similar mass. In species of similar mass experiencing significantly different detachment stress (resulting from significantly different contact area), differences in morphology or behavior affect how much body surface is attached to the substrate. High performance in some species, such as Desmognathus quadramaculatus, is attributable to large contact area; low performance in a similarly sized species, Ensatina eschscholtzii, is due to behavior that negatively impacts contact area. There was no clear evidence of scaling of adhesive strength with increasing body size. Salamander maximum cling angle is the result of morphology and behavior impacting the detachment stresses experienced during clinging.

3D biofilm visualization and quantification on granular bioanodes with magnetic resonance imaging

The use of microbial fuel cells (MFCs) for wastewater treatment fits in a circular economy context, as they can produce electricity by the removal of organic matter in the wastewater. Activated carbon (AC) granules are an attractive electrode material for bioanodes in MFCs, as they are cheap and provide electroactive bacteria with a large surface area for attachment. The characterization of biofilm growth on AC granules, however, is challenging due to their high roughness and three-dimensional structure. In this research, we show that 3D magnetic resonance imaging (MRI) can be used to visualize biofilm distribution and determine its volume on irregular-shaped single AC granules in a non-destructive way, while being combined with electrochemical and biomass analyses. Ten AC granules with electroactive biofilm (i.e. granular bioanodes) were collected at different growth stages (3 to 21 days after microbial inoculation) from a multi-anode MFC and T1-weighted 3D-MRI experiments were performed for three-dimensional biofilm visualization. With time, a more homogeneous biofilm distribution and an increased biofilm thickness could be observed in the 3D-MRI images. Biofilm volumes varied from 0.4 μL (day 4) to 2 μL (day 21) and were linearly correlated (R2 = 0.9) to the total produced electric charge and total nitrogen content of the granular bioanodes, with values of 66.4 C μL−1 and 17 μg N μL−1, respectively. In future, in situ MRI measurements could be used to monitor biofilm growth and distribution on AC granules.

Micro-macrobubbles interactions and its application in flotation technology for the recovery of high density oil from contaminated sands

The integration of microbubbles (Sauter diameter: 80 μm) and macrobubbles (Sauter diameter: 0.9 mm) in a flotation system were proposed to enhance oil removal efficiencies. The role of the microbubbles as a secondary collector for macrobubbles was studied in the static bubble interaction studies in terms of attachment time, contact angle and visualization of contact area. Results showed that the presence of microbubbles could decrease the attachment time between macrobubbles and oil layer by 82%, and improve the contact angle and surface area of attachment by 40.3% and 54.5% respectively. Macrobubbles, on the other hand were able to improve the floatability of oil contaminant as suggested from the dynamic bubble interaction study. The presence of macrobubbles was able to increase the volumetric rate of micro-macrobubbles captured from 0.47 μL/s to 4.5 μL/s. The results demonstrated that the coalescence phenomena between bubbles could provide the necessary lifting force to further aid the oil flotation. The interaction between microbubbles and macrobubbles is particularly advantageous in an integrated bubble flotation system. Application of the integrated micro-macrobubbles demonstrated a significant increase in oil removal to 68.6% under oil-wet conditions while almost all of the oil contaminants were removed from water-wet sands. An increase of 28% was observed upon implementation of integrated micro-macrobubble flotation compared to the single bubble flotation for oil removal. Results indicated that the integration of microbubbles and macrobubbles in the flotation cell is a simple modification to a flotation system that would enhance the removal of oil contaminant from contaminated sand.

Seasonality and vertical distribution of epiphytic diatoms on the pneumatophore surface of mangrove Avicennia officinalis L.

Mangrove pneumatophores (respiratory roots) form a unique habitat about which very little ecological information is available. In this study, epiphytic diatoms on the pneumatophore surface of Avicennia officinalis (L.) were investigated with a focus on their seasonal and vertical distribution. The results indicated that among the seasons, highest diatom abundance was observed in monsoon. Vertically, maximum abundance was observed on 0–5 cm of the pneumatophore during post-monsoon and pre-monsoon and then gradually decreased upwards, but during monsoon, 5–10 cm section hosted maximum abundance. There was a seasonal and vertical variation on the diatom abundance and their interactive effect. This is because diatoms probably avoid the basal section (0–5 cm) of the pneumatophore during monsoon due to excessive sediment burial caused by intense riverine flux and settlement of suspended material. Overall it was found that vertically, diatoms (>70%) are mainly concentrated on the lower 0–10 cm of the pneumatophore, probably because this section remains moist during emersion period (low tide). Among the diatoms, Melosira nummuloides and Bacillaria paradoxa exhibited dominance during the monsoon, whereas Thalassiosira spp., Navicula spp., and Nitzschia spp.were prevalent during post- and pre-monsoon. To the best of our knowledge, this is the first study describing the composition of epiphytic diatoms from the pneumatophore surface of A. officinalis. Keeping in mind that these aerial roots together greatly enhance the surface area for attachment of epiphytic diatoms, their cumulative primary production would probably surpass that of mangroves on a quantitative basis and needs future investigation.

Accumulation of 111In-Labelled EGF-Au-PEG Nanoparticles in EGFR-Positive Tumours is Enhanced by Coadministration of Targeting Ligand.

The successful use of targeted radionuclide therapy in the treatment of solid tumours may be limited by radioresistance, which necessitates delivery of a high dose of radioactivity. Nanoparticle (NP)-based delivery systems possess a large surface area for attachment of radioisotopes and so offer a solution to this challenge. However, tumour uptake may be limited by rapid hepatic clearance of NP via the mononuclear phagocyte system. Liver uptake is further compounded when epidermal growth factor (EGF) is used as a targeting ligand, as EGF-tagged NP bind the EGF receptor (EGFR), which is expressed to a moderate extent by hepatocytes. This report describes an indium-111 (111In)-labelled PEGylated EGF-tagged gold (Au) NP (111In-EGF-Au-PEG) and an effective strategy of coadministration of targeting ligand to address these issues. Direct attachment of EGF to the surface of Au NP did not compromise surface coating with long-chain PEG. In vitro experiments showed that 111In-EGF-Au-PEG targets EGFR-positive cancer cells (MDA-MB-468): >11% of radioactivity was internalised after incubation for 4 h. In in vivo studies accumulation of NP was observed in MDA-MB-468 xenografts and tumour uptake was enhanced by the coadministration of 15 µg of the unlabelled targeting ligand, EGF, to block hepatic EGFR. Uptake was 3.9% versus 2.8% injected dose/g (%ID/g) of tumour tissue with and without unlabelled EGF, respectively. Coadministration of EGF reduced liver uptake by 25.95% to 7.56 %ID/g. This suggests that the coadministration of unlabelled targeting ligand with radiolabelled PEGylated NP offers a promising strategy for targeting EGFR-positive cancer and for minimising liver uptake.

CRYOGELS BASED ON POLYELECTROLYTE COMPLEX BETWEEN CHITOSAN AND GELATIN FORMED UNDER CRYOCONDITIONS FOR TISSUE ENGINEERING

Cryogelation technique is a versatile technique for design of various biocompatible scaffolds based on natural polymers as gelatin(Gel), chitosan and casein using cryogelation technique. [1-4] Cryogelation is the process of the formation of macroporous polymer systems, so called cryogels, with well-developed 3D structure of interconnected pores. Cryogels have porosity of 90-95% and macro-channels of 20-150 µm in size. Interconnected pores provide unrestricted penetration of nutrients and provides high surface area for attachment and proliferation of mammalian cells.[1,2] Previously, the preparation of Gel based cryogel was carried out in environmentally friendly way using enzymatic reaction under cryoconditions.[3] To prepare stable materials we developed a preparation method allowing avoid the use of toxic reducing agent borohydride for reduction of Schiff's base.[4] In this study we used dextran dialdehyde as a mild nontoxic cross-linker for preparation of cryogels based on different types of gelatin and chitosan. Additionally the cryogels were cross-linked via formation of polyelectrolyte complex(PEC) between oppositely charged groups of gelatine and chitosan. Physico-chemical properties, elastic modulus and degradation of the materials based on different ratios of dextran-gelatin anddextran-gelatin-chitosan at physiological conditions were inverstigated. Human hepatic epithelial cell culture line and fibroblasts cells grow in the dextran-gelatin-chitosan cryogel scaffolds were studied. The type of gelatin significantly affected the migration, proliferation of cell and also microscopic morphology of the scaffold. The dextran-chitosan-gelatin (fish)(1:1:1wt %) based materials show better fibroblast growth compare to dextran-fish gelatin only. The cryogels containing dextran-chitosan-gelatin(bovine A)(1:1:1wt %) revealed good attachment and proliferation of hepatocytes inside of the material, whereas the cell line formed clusters on the surface of the PEC cryogel based on dextran-chitosan-gelatin(bovine A)(Fig. 1).

Influence of aquatic plant architecture on epiphyte biomass on a tropical river floodplain

Tropical floodplains are highly productive because of seasonal replenishment of water and nutrients, which substantially boost primary productivity. This study examined how the architecture of aquatic macrophytes affect the light and water quality and consequently the attachment and biomass of epiphytes on a floodplain in northern Australia. Results show that macrophyte structural complexity is not only important for water column light penetration but also for the development of epiphytes on macrophytes. Emergent grasses with simple vertical structure and high plant densities, limit light penetration and consequently the development and biomass of epiphytic algae. In contrast, submerged macrophytes growing just below the water surface, allow greater light penetration. The complex architecture of submerged macrophytes also provides a large surface area for the development of a dense covering of epiphytic algae. Other plant structural forms (e.g., plants with floating leaves) have a simple structure, variable light penetration and low epiphytic algae biomass. The emergent grass Pseudoraphis spinescens (R.Br.) Vickery also had low light penetration but the horizontal alignment of stems across the water surface allow greater exposure to sunlight of the stems and the consequent development of epiphytic algae. We conclude that (1) the complex structure of submerged plants effectively creates a “false bottom” in deeper waters so that they function similarly to the floodplain's littoral zone, and (2) that their extremely large surface area for attachment allows greater production of epiphytic algae than would occur on the sediment surface.

Morphological, developmental, and ecological characteristics of the suctorian ciliate Ephelota gigantea (Ciliophora, Phyllopharyngea, Ephelotidae) found on cultured wakame seaweed in Northeastern Japan

Wakame seaweed is an important aquatic resource in Iwate Prefecture. However, a suctorian Ephelota gigantea sometimes causes great damage to wakame culture. Since little is known about the biological characteristics of E. gigantea , its detailed morphology and temporal change of biological characteristics during the 2010 culture season were investigated. Scanning electron microscope observations showed that E. gigantea had different striation patterns on the stalk; there was a swell made of cement by which the stalk was attached to wakame firmly; and the buds had cilia arranged in concentric circles about a ring in the center of the ventral side. A suctorian parasite was found to infect E. gigantea , and the infection seemed to have decreased drastically the attached density of E. gigantea on wakame. Cell size of parasite-infected E. gigantea individuals was larger than that of uninfected individuals, probably because larger E. gigantea has larger surface area for attachment of the parasite. Cyst formation or conjugating individuals were not observed.

Pes Anserinus Structural Framework and Constituting Tendons Are Grossly Aberrant in Nigerian Population.

We evaluated the morphological framework of the pes anserinus in both knees of ten Nigerian cadavers and we observed high degree of variability in its morphology and location. The pes anserinus inserted specifically on the superior half of the media border of the tibia, as far inferiorly as 124.44 mm to the tibial tuberosity (prolonged insertion). The insertion was also joined to the part of tibia close to the tibia tuberosity (90%) and to the fascia cruris (10%). The initial insertion point of the pes anserinus was always found at the level of the tibia tuberosity. We found out that accessory bands of sartorius, gracilis, or semitendinosus were part of the pes anserinus in 95% of all occasions studied whereas the combined occurrence of monotendinosus sartorius, gracilis, and semitendinosus tendons was found in only 5% of all occasions. The pes anserinus did not conform to the layered pattern and the tendons of sartorius, gracilis, or semitendinosus were short. The inferior prolongation of the pes anserinus connotes extended surface area of attachment to support the mechanical pull from the hamstring muscles. This information will be useful in precise location and grafting of the pes anserinus.

An attachment-based description of the medial collateral and spring ligament complexes.

Anatomy of the medial collateral and spring ligament complexes has been the cause of confusion. The anatomic description is highly dependent on the source studied and little agreement exists between texts. In addition, inconsistent nomenclature has been used to describe the components. This study attempted to clarify confusion through the creation of a 3D ligament map using attachment-based dissection. Nine fresh foot and ankle specimens were observed. The medial collateral ligament and spring ligament complexes were dissected using their attachment sites as a guide to define individual components. Each component's perimeter and thickness was measured and each bony attachment was mapped using a microscribe 3D digitizer. Five components were identified contributing to the ligament complexes of interest: the tibiocalcaneonavicular, superficial posterior tibiotalar, deep posterior tibiotalar, deep anterior tibiotalar, and inferoplantar longitudinal ligaments. The largest component by total attachment area was the tibiocalcaneonavicular ligament followed by the deep posterior tibiotalar ligament. The largest ligament surface area of attachment to the tibia and talus was the deep posterior tibiotalar ligament. The largest attachment to the navicular and calcaneus was the tibiocalcaneonavicular ligament, which appeared to function in holding these bones in proximity while supporting the head of the talus. By defining complex components by their attachment sites, a novel, more functional and reproducible description of the medial collateral and spring ligament complexes was created. The linear measurements and 3D maps may prove useful when attempting more anatomically accurate reconstructions.

The density and spatial arrangement of the invasive oyster Crassostrea gigas determines its impact on settlement of native oyster larvae

Understanding how the density and spatial arrangement of invaders is critical to developing management strategies of pest species. The Pacific oyster, Crassostrea gigas, has been translocated around the world for aquaculture and in many instances has established wild populations. Relative to other species of bivalve, it displays rapid suspension feeding, which may cause mortality of pelagic invertebrate larvae. We compared the effect on settlement of Sydney rock oyster, Saccostrea glomerata, larvae of manipulating the spatial arrangement and density of native S. glomerata, and non-native C. gigas. We hypothesized that while manipulations of dead oysters would reveal the same positive relationship between attachment surface area and S. glomerata settlement between the two species, manipulations of live oysters would reveal differing density-dependent effects between the native and non-native oyster. In the field, whether oysters were live or dead, more larvae settled on C. gigas than S. glomerata when substrate was arranged in monospecific clumps. When, however, the two species were interspersed, there were no differences in larval settlement between them. By contrast, in aquaria simulating a higher effective oyster density, more larvae settled on live S. glomerata than C. gigas. When C. gigas was prevented from suspension feeding, settlement of larvae on C. gigas was enhanced. By contrast, settlement was similar between the two species when dead. While the presently low densities of the invasive oyster C. gigas may enhance S. glomerata larval settlement in east Australian estuaries, future increases in densities could produce negative impacts on native oyster settlement. Synthesis and applications: Our study has shown that both the spatial arrangement and density of invaders can influence their impact. Hence, management strategies aimed at preventing invasive populations reaching damaging sizes should not only consider the threshold density at which impacts exceed some acceptable limit, but also how patch formation modifies this.