Apicoplast phylogeny reveals the position of Plasmodium vivax basal to the Asian primate malaria parasite clade

The malaria parasite species, Plasmodium vivax infects not only humans, but also African apes. Human specific P. vivax has evolved from a single ancestor that originated from a parasite of African apes. Although previous studies have proposed phylogenetic trees positioning P. vivax (the common ancestor of human and African ape P. vivax) within the assemblages of Asian primate parasites, its position has not yet been robustly confirmed. We determined nearly complete apicoplast genome sequences from seven Asian primate parasites, Plasmodium cynomolgi (strains Ceylonensis and Berok), P. knowlesi P. fragile, P. fieldi, P. simiovale, P. hylobati, P. inui, and an African primate parasite, P. gonderi, that infects African guenon. Phylogenetic relationships of the Plasmodium species were analyzed using newly and previously determined apicoplast genome sequences. Multigene maximum likelihood analysis of 30 protein coding genes did not position P. vivax within the Asian primate parasite clade but positioned it basal to the clade, after the branching of an African guenon parasite, P. gonderi. The result does not contradict with the emerging notion that P. vivax phylogenetically originated from Africa. The result is also supported by phylogenetic analyses performed using massive nuclear genome data of seven primate Plasmodium species

Correlation between musculoskeletal structure of the hand and primate locomotion: Morphometric and mechanical analysis in prehension using the cross- and triple-ratios

Biometric ratios of the relative length of the rays in the hand have been analyzed between primate species in the light of their hand function or phylogeny. However, how relative lengths among phalanges are mechanically linked to the grasping function of primates with different locomotor behaviors remains unclear. To clarify this, we calculated cross and triple-ratios, which are related to the torque distribution, and the torque generation mode at different joint angles using the lengths of the phalanges and metacarpal bones in 52 primates belonging to 25 species. The torque exerted on the finger joint and traction force of the flexor tendons necessary for a cylindrical grip and a suspensory hand posture were calculated using the moment arm of flexor tendons measured on magnetic resonance images, and were compared among\ua0Hylobates\ua0spp.,\ua0Ateles\ua0sp., and\ua0Papio hamadryas. Finally, the torques calculated from the model were validated by a mechanical study detecting the force exerted on the phalanx by pulling the digital flexor muscles during suspension in these three species. Canonical discriminant analysis of cross and triple-ratios classified primates almost in accordance with their current classification based on locomotor behavior. The traction force was markedly reduced with flexion of the MCP joint parallel to the torque in brachiating primates; this was notably lower in the terrestrial quadrupedal primates than in the arboreal primates at mild flexion. Our mechanical study supported these features in the torque and traction force generation efficiencies. Our results suggest that suspensory or terrestrial quadrupedal primates have hand structures that can exert more torque at a suspensory posture, or palmigrade and digitigrade locomotion, respectively. Furthermore, our study suggests availability of the cross and triple-ratios as one of the indicators to estimate the hand function from the skeletal structure

Correlation between musculoskeletal structure of the hand and primate locomotion: Morphometric and mechanical analysis in prehension using the cross- and triple-ratios.

Biometric ratios of the relative length of the rays in the hand have been analyzed between primate species in the light of their hand function or phylogeny. However, how relative lengths among phalanges are mechanically linked to the grasping function of primates with different locomotor behaviors remains unclear. To clarify this, we calculated cross and triple-ratios, which are related to the torque distribution, and the torque generation mode at different joint angles using the lengths of the phalanges and metacarpal bones in 52 primates belonging to 25 species. The torque exerted on the finger joint and traction force of the flexor tendons necessary for a cylindrical grip and a suspensory hand posture were calculated using the moment arm of flexor tendons measured on magnetic resonance images, and were compared among Hylobates spp., Ateles sp., and Papio hamadryas. Finally, the torques calculated from the model were validated by a mechanical study detecting the force exerted on the phalanx by pulling the digital flexor muscles during suspension in these three species. Canonical discriminant analysis of cross and triple-ratios classified primates almost in accordance with their current classification based on locomotor behavior. The traction force was markedly reduced with flexion of the MCP joint parallel to the torque in brachiating primates; this was notably lower in the terrestrial quadrupedal primates than in the arboreal primates at mild flexion. Our mechanical study supported these features in the torque and traction force generation efficiencies. Our results suggest that suspensory or terrestrial quadrupedal primates have hand structures that can exert more torque at a suspensory posture, or palmigrade and digitigrade locomotion, respectively. Furthermore, our study suggests availability of the cross and triple-ratios as one of the indicators to estimate the hand function from the skeletal structure

Production of 11C-beam for particle therapy

A technical realization of a positron emitter 11C-beam (R.I.) as an accelerating beam has been studied at NIRS-HIMAC in order to apply it to heavy-ion therapy. The purpose of the present study is to show how to obtain a suitable beam intensity of a 11C-beam extracted from the HIMAC-synchrotron. Regarding this study, related developmentsinclude the production of radioactive isotopes (11C) by a cyclotron, gas-separation, gas-compression, gas-pulsing and ionization. Further, residue 11CO2-gas can be reproduced in the ionization process. As the result of a calculation, an order of 108 ppp of 11C6+ ions can be extracted from the HIMAC-synchrotron during 18 min at 3.3 s intervals with a 1 ms beam pulse under the assumption of 1 Ci of 11C-production. Details of the study are presented

Comparison of Brain Temperature Distribution in Mathematical and Solid Models of Head Thermal Characteristics

SUMMARY Accurate temperature control of brain tissue during hypothermia treatment is necessary in order to prevent secondary brain damage and to avoid various side effects. Thus, the visualization of the intracerebral temperature distribution in hypothermia treatment was studied at the fundamental level. For this purpose a virtual reality technology was used to create a mathematical model that reflects metabolic heat production and Fourier heat conduction in a brain with the necessary parameters based on various clinical models. In the present study, an experimental system was developed to examine a mathematical simulation of the blood flow in a human head by using a solid brain model constructed using silicon rubber in the shape of a brain based on MRI data, taking into account the metabolic heat given off by three film heaters and including six sensors for the measurement of regional brain temperature. The mathematical simulation describes the internal temperature distribution in a brain with a similar structure to the brain solid model. The results of mathematical simulations and experiments using the brain solid model were quite consistent in the steady state, including control of regional temperature. This allows for the performance of heat conduction experiments under conditions similar to those of a living body, in which the internal temperature is clinically difficult to observe. Thus, the mathematical simulation is confirmed to be useful together with experiments using the solid model for the study of future brain hypothermia treatment. C⃝ 2015 Wiley Periodicals, Inc. Electr Eng Jpn, 193(2): 58-68, 2015; Published online in Wiley Online Library (wileyonlinelibrary.com)

Low-energy ion decelerator for an external injection line at the NIRS-930 cyclotron

A low-energy ion decelerator for the acceleration-deceleration system has been designed and installed in the beam-injection line of the NIRS-930 cyclotron in an attempt to increase the beam intensity from the cyclotron. With this acceleration-deceleration system, the beam intensity of C-12(4+) ions at the cyclotron exit has been increased by about five times. The system has an advantage in that it allows us to extract a high-current ion beam from an electron cyclotron resonance ion source because, independently of the injection-energy matching to the cyclotron, a large potential difference can be applied between the source and the extractor. The voltage applied to the extractor is about -12 kV, which is reduced to the ground potential by the decelerator. The electric field distributions in the deceleration system were carefully designed using a three-dimensional field simulator. Design studies of the decelerator as well as the result of a beam test are presented