Traditional and geometric morphometrics detect morphological variation of lower pharyngeal jaw inCoris julis(Teleostei, Labridae)

In the present study, variation in the morphology of the lower pharyngeal element between two Sicilian populations of the rainbow wrasse Coris julis has been explored by the means of traditional morphometrics for size and geometric morphometrics for shape. Despite close geographical distance and probable high genetic flow between the populations, statistically significant differences have been found both for size and shape. In fact, one population shows a larger lower pharyngeal element that has a larger central tooth. Compared to the other population, this population also has medially enlarged lower pharyngeal jaws with a more pronounced convexity of the medial-posterior margin. The results are discussed in the light of a possible more pronounced durophagy of this population.

Magnetic and morphological properties of ferrofluid-impregnated hydroxyapatite/collagen scaffolds

In this article we present the morphological and magnetic characterization of ferrofluid-impregnated biomimetic scaffolds made of hydroxyapatite and collagen used for bone reconstruction. We describe an innovative and simple impregnation process by which the ferrofluid is firmly adsorbed onto the hydroxyapatite/collagen scaffolds. The process confers sufficient magnetization to attract potential magnetic carriers, which may be used to transport bioactive agents that favour bone regeneration. The crystalline structure of the magnetite contained in the ferrofluid is preserved and its quantity, estimated from the weight gain due to the impregnation process, is consistent with that obtained from energy dispersive X-ray spectroscopy. The magnetization, measured with a superconducting quantum interference device, is uniform throughout the scaffolds, demonstrating the efficiency of the impregnation process. The field emission gun scanning electron microscopy characterization demonstrates that the process does not alter the morphology of the hydroxyapatite/collagen scaffolds, which is essential for the preservation of their bioactivity and consequently for their effectiveness in promoting bone formation.

Inhibition by poly(acrylic acid) and morphological changes in calcium carbonate and calcium carbonate/calcium sulfate crystallization on silica fibers

An intrinsic exposed core optical fiber sensor (IECOFS) made from fused silica was used to monitor the crystallization of calcium carbonate (CaCO3) and CaCO3/calcium sulfate (CaSO4) composite at 100 and 120 °C in the absence and presence of low-molar-mass (Mn ≤ 2000) poly(acrylic acid) (PAA) with different end groups. The IECOFS responded only to deposition and growth processes on the fiber surface rather than changes occurring in the bulk of the solution. Hexyl isobutyrate-terminated PAA (Mn = 1400) and hexadecyl isobutyrate-terminated PAA (Mn = 1700) were the most effective species in preventing CaCO3 deposition. Phase transformation from vaterite to aragonite/calcite decreased with increasing hydrophobicity of the PAA end group. Low-molar-mass PAA at 10 ppm showed very significant inhibition of CaCO3/CaSO4 composite formation for all end groups investigated.

Fear memory reactivation after extinction activates plasticity in the lateral amygdala

Little is known about the neuronal changes that occur within the lateral amygdala (LA) following fear extinction. In fear extinction, the repeated presentation of a conditioned stimulus (CS), in the absence of a previously paired aversive unconditioned stimulus (US), reduces fear elicited by the CS. Fear extinction is an active learning process that leads to the formation of a consolidated extinction memory, however it is fragile and prone to spontaneous recovery and renewal under environmental changes such as context. Understanding the neural mechanisms underlying fear extinction is of great clinical relevance, as psychological treatments of several anxiety disorders rely largely on extinction-based procedures and relapse is major clinical problem. This study investigated plasticity in the LA following fear memory reactivation in rats with and without extinction training. Phosphorylated MAPK (p44/42 ERK/MAPK), a protein kinase required in the amygdala for fear learning and its extinction, was used as a marker for neuronal plasticity. Rats (N = 11) underwent a Pavlovian auditory fear conditioning and extinction paradigm, and later received a single conditioned stimulus presentation to reactivate the fear memory. Results showed more pMAPK+ expressing neurons in the LA following extinction-reactivation compared to control rats, with the largest number of pMAPK+ neurons counted in the ventral LA, especially including the ventro-lateral subdivision (LAvl). These findings indicate that LA subdivision specific plasticity occurs to the conditioned fear memory in the LAvl following extinction-reactivation. These findings provide important insight into the organisation of fear memories in the LA, and pave the way for future research in the memory mechanisms of fear extinction and its pathophysiology.

Foot morphological difference between habitually shod and unshod runners

Foot morphology and function has received increasing attention from both biomechanics researchers and footwear manufacturers. In this study, 168 habitually unshod runners (90 males whose age, weight & height were 23 +/- 2.4years, 66 +/- 7.1kg & 1.68 +/- 0.13m and 78 females whose age, weight & height were 22 +/- 1.8years, 55 +/- 4.7kg & 1.6 +/- 0.11m) (Indians) and 196 shod runners (130 males whose age, weight & height were 24 +/- 2.6years, 66 +/- 8.2kg & 1.72 +/- 0.18m and 66 females whose age, weight & height were 23 +/- 1.5years, 54 +/- 5.6kg & 1.62 +/- 0.15m)(Chinese) participated in a foot scanning test using the easy-foot-scan (a three-dimensional foot scanning system) to obtain 3D foot surface data and 2D footprint imaging. Foot length, foot width, hallux angle and minimal distance from hallux to second toe were calculated to analyze foot morphological differences. This study found that significant differences exist between groups (shod Chinese and unshod Indians) for foot length (female p = 0.001), width (female p = 0.001), hallux angle (male and female p = 0.001) and the minimal distance (male and female p = 0.001) from hallux to second toe. This study suggests that significant differences in morphology between different ethnicities could be considered for future investigation of locomotion biomechanics characteristics between ethnicities and inform last shape and design so as to reduce injury risks and poor performance from mal-fit shoes.

Morphological changes in the conjunctiva, episclera and sclera following short-term miniscleral contact lens wear in rigid lens neophytes

PURPOSE To quantify the influence of short-term wear of miniscleral contact lenses on the morphology of the corneo-scleral limbus, the conjunctiva, episclera and sclera. METHODS OCT images of the anterior eye were captured before, immediately following 3h of wear and then 3h after removal of a miniscleral contact lens for 10 young (27±5 years) healthy participants (neophyte rigid lens wearers). The region of analysis encompassed 1mm anterior, to 3.5mm posterior to the scleral spur. Natural diurnal variations in thickness were measured on a separate day and compensated for in subsequent analyses. RESULTS Following 3h of lens wear, statistically significant tissue thinning was observed across all quadrants, with a mean decrease in thickness of -24.1±3.6μm (p<0.001), which diminished, but did not return to baseline 3h after lens removal (-16.9±1.9μm, p<0.001). The largest tissue compression was observed in the superior quadrant (-49.9±8.5μm, p<0.01) and in the annular zone 1.5mm from the scleral spur (-48.2±5.7μm), corresponding to the approximate edge of the lens landing zone. Compression of the conjunctiva/episclera accounted for about 70% of the changes. CONCLUSIONS Optimal fitting miniscleral contact lenses worn for three hours resulted in significant tissue compression in young healthy eyes, with the greatest thinning observed superiorly, potentially due to the additional force of the eyelid, with a partial recovery of compression 3h after lens removal. Most of the morphological changes occur in the conjunctiva/episclera layers.

A note on sampling chironomids for RNA-based studies of natural populations that retains critical morphological vouchers

The rapid uptake of transcriptomic approaches in freshwater ecology has seen a wealth of data produced concerning the ways in which organisms interact with their environment on a molecular level. Typically, such studies focus either at the community level and so don’t require species identifications, or on laboratory strains of known species identity or natural populations of large, easily identifiable taxa. For chironomids, impediments still exist for applying these technologies to natural populations because they are small-bodied and often require time-consuming secondary sorting of stream material and morphological voucher preparation to confirm species diagnosis. These procedures limit the ability to maintain RNA quantity and quality in such organisms because RNA degrades rapidly and gene expression can be altered rapidly in organisms; thereby limiting the inclusion of such taxa in transcriptomic studies. Here, we demonstrate that these limitations can be overcome and outline an optimised protocol for collecting, sorting and preserving chironomid larvae that enables retention of both morphological vouchers and RNA for subsequent transcriptomics purposes. By ensuring that sorting and voucher preparation are completed within <4 hours after collection and that samples are kept cold at all times, we successfully retained both RNA and morphological vouchers from all specimens. Although not prescriptive in specific methodology, we anticipate that this paper will assist in promoting transcriptomic investigations of the sublethal impact on chironomid gene expression of changes to aquatic environments.

Characterisation of head-hardened rail steel in terms of cyclic plasticity response and microstructure for improved material modelling

Stress- and strain-controlled tests of heat treated high-strength rail steel (Australian Standard AS1085.1) have been performed in order to improve the characterisation of the said material׳s ratcheting and fatigue wear behaviour. The hardness of the rail head material has also been studied and it has been found that hardness reduces considerably below four-millimetres from the rail top surface. Historically, researchers have used test coupons with circular cross-sections to conduct cyclic load tests. Such test coupons, typically five-millimetres in gauge diameter and ten‐millimetres in grip diameter, are usually taken from the rail head sample. When there is considerable variation of material properties over the cross-section it becomes likely that localised properties of the rail material will be missed. In another case from the literature, disks 47 mm in diameter for a twin-disk rolling contact test machine were obtained directly from the rail sample and used to validate ratcheting and rolling contact fatigue wear models. The question arises: How accurate are such tests, especially when large material property gradients exist? In this research paper, the effects of rail sampling location on the ratcheting behaviour of AS1085.1 rail steel were investigated using rectangular-shaped specimens obtained at four different depths to observe their respective cyclic plasticity behaviour. The microstructural features of the test coupons were also analysed, especially the pearlite inter-lamellar spacing which showed strong correlation with both hardness and cyclic plasticity behaviour of the material. This work ultimately provides new data and testing methodology to aid the selection of valid parameters for material constitutive models to better understand rail surface ratcheting and wear.