This paper presents a numerical study of the thermal performance of fins mounted on the bottom wall of a horizontal channel and cooled with either pure water or an Al2O3-water nanofluid. The bottom wall of the channel is heated at a constant temperature and cooled by mixed convection of laminar flow at a relatively low temperature. The results of the numerical simulation indicate that the heat ...

Some principles governing the design of invertebrate paired propulsive appendages are discussed, with particular reference to the extent to which information encoded in their skeletal structure determines their instantaneous shape in locomotion. The hydrostatic paired fins of some cephalopods and marine gastropods, polychaete parapodia and onychophoran lobopodia rely entirely on musculature for...

Neural connectivity between the spinal cord and paired appendages is key to the superior locomotion of tetrapods and aquatic vertebrates. In contrast to nerves that innervate axial muscles, those innervating appendages converge at a specialized structure, the plexus, where they topographically reorganize before navigating towards their muscle targets. Despite its importance for providing append...

In zebrafish, mutations in the gap junction gene connexin43 lead to short bony fin ray segments that give rise to the short fin phenotype. The sof(b123) mutant exhibits fins that are half the length of wild-type fins and have reduced levels of cx43 mRNA. We find that sof(b123) regenerating fins exhibit reduced levels of cell proliferation. Interestingly, the number of dividing cells per unit le...

Larval zebrafish innately perform a suite of behaviors that are tightly linked to their evolutionary past, notably escape from threatening stimuli and pursuit and capture of prey. These behaviors have been carefully examined in the past, but mostly with regard to the movements of the trunk and tail of the larvae. Here, we employ kinematics analyses to describe the movements of the pectoral fins...

A number of physiological processes in living organisms involve the selective "catch and release" of biomolecules. Inspired by these biological processes, we use computational modeling to design synthetic systems that can controllably catch, transport, and release specific molecules within the surrounding solution, and, thus, could be harnessed for effective separation processes within microflu...

Immune mechanisms in 2 strains of Salmo salar (Baltic salmon from River Ume Alv in Sweden and East Atlantic salmon from River Skjernå in Denmark) infected with the monogenean ectoparasite Gyrodactylus salaris were elucidated by molecular tools (real-time PCR). The gene expression in the fins (the preferred microhabitat of the parasite) of the susceptible but responding Swedish salmon was compar...

For many fish species, the pectoral fins serve as important propulsors and stabilizers and are precisely controlled. Although it has been shown that mechanosensory feedback from the fin ray afferent nerves provides information on ray bending and position, the effects of this feedback on fin movement are not known. In other taxa, including insects and mammals, sensory feedback from the limbs has...

The body and fins of the zebrafish grow rapidly as juveniles and slower as they reach maturation. Throughout their lives, the fins grow isometrically with respect to the body. Growth of individual fin rays is achieved by the distal addition of bony segments. We have investigated the genetic control of mechanisms that initiate new segments or control size of newly initiated segments. We find tha...