The influence of acceleration loading curve characteristics on traumatic brain injury

To prevent brain trauma, understanding the mechanism of injury is essential. Once the mechanism of brain injury has been identified, prevention technologies could then be developed to aid in their prevention. The incidence of brain injury is linked to how the kinematics of a brain injury event affects the internal structures of the brain. As a result it is essential that an attempt be made to describe how the characteristics of the linear and rotational acceleration influence specific traumatic brain injury lesions. As a result, the purpose of this study was to examine the influence of the characteristics of linear and rotational acceleration pulses and how they account for the variance in predicting the outcome of TBI lesions, namely contusion, subdural hematoma (SDH), subarachnoid hemorrhage (SAH), and epidural hematoma (EDH) using a principal components analysis (PCA). Monorail impacts were conducted which simulated falls which caused the TBI lesions. From these reconstructions, the characteristics of the linear and rotational acceleration were determined and used for a PCA analysis. The results indicated that peak resultant acceleration variables did not account for any of the variance in predicting TBI lesions. The majority of the variance was accounted for by duration of the resultant and component linear and rotational acceleration. In addition, the components of linear and rotational acceleration characteristics on the x, y, and z axes accounted for the majority of the remainder of the variance after duration.     

Growth responses of barley seedling to simulated weightlessness induced by two-axis rotation

Summary A device used for simulated weightless studies is described and is called the Nogravatron. The Nogravatron apparatus produces simulated weight-lessness by rotating seedlings simultaneously at the rate of 0.25 rpm and 1.0 rpm in two axes perpendicular to each other. Atlas barley seedlings grown on the apparatus grew at rates different from that of stationary controls. Coleoptile elongation in rotated barley was not inhibited by light during the first 55 hours of rotation treatment whereas stationary controls were photoinhibited. After 55 hours the growth of rotated coleoptiles was inhibited by light. The coleoptiles did not show movements and were oriented along the longitudinal axis of the seed. Roots also did not show geotropic movements but the growth direction was affected by the proximity of other roots. Coleoptiles rotated in dark were significantly longer than stationary controls on the third and fourth day but not so on the fifth day and later. Coleoptiles rotated in light were about 35 percent longer than the stationary coleoptiles by the third day and maintained this significant difference to the end of the experiment.Supported in part by NASA Grant NsG 538-63 and by Air Force Office of Scientific Research Office of Aerospace Research, United States Air Force, Contract No. AF 49 (638)-1387.     

Ecosystem Services in Conservation Planning: Targeted Benefits vs. Co-Benefits or Costs?

There is growing support for characterizing ecosystem services in order to link conservation and human well-being. However, few studies have explicitly included ecosystem services within systematic conservation planning, and those that have follow two fundamentally different approaches: ecosystem services as intrinsically-important targeted benefits vs. substitutable co-benefits. We present a first comparison of these two approaches in a case study in the Central Interior of British Columbia. We calculated and mapped economic values for carbon storage, timber production, and recreational angling using a geographical information system (GIS). These 'marginal' values represent the difference in service-provision between conservation and managed forestry as land uses. We compared two approaches to including ecosystem services in the site-selection software Marxan: as Targeted Benefits, and as Co-Benefits/Costs (in Marxan's cost function); we also compared these approaches with a Hybrid approach (carbon and angling as targeted benefits, timber as an opportunity cost). For this analysis, the Co-Benefit/Cost approach yielded a less costly reserve network than the Hybrid approach (1.6% cheaper). Including timber harvest as an opportunity cost in the cost function resulted in a reserve network that achieved targets equivalently, but at 15% lower total cost. We found counter-intuitive results for conservation: conservation-compatible services (carbon, angling) were positively correlated with each other and biodiversity, whereas the conservation-incompatible service (timber) was negatively correlated with all other networks. Our findings suggest that including ecosystem services within a conservation plan may be most cost-effective when they are represented as substitutable co-benefits/costs, rather than as targeted benefits. By explicitly valuing the costs and benefits associated with services, we may be able to achieve meaningful biodiversity conservation at lower cost and with greater co-benefits.     

Finite element analysis of the effect of loading curve shape on brain injury predictors

Prediction of traumatic and mild traumatic brain injury is an important factor in managing their prevention. Currently, the prediction of these injuries is limited to peak linear and angular acceleration loading curves derived from laboratory reconstructions. However it remains unclear as to what aspect of these loading curves contributes to brain tissue damage. This research uses the University College Dublin Brain Trauma Model (UCDBTM) to analyse three distinct loading curve shapes meant to represent different helmet loading scenarios. The loading curves were applied independently in each axis of linear and angular acceleration and their effect on currently used predictors of TBI and mTBI was examined. Loading curve shape A had a late time to peak, B an early time to peak and C had a consistent plateau. The areas under the curve for all three loading curve shapes were identical. The results indicate that loading curve A produced consistently higher maximum principal strains and Von Mises stress than the other two loading curve types. Loading curve C consistently produced the lowest values of maximum principal strain and Von Mises stress, with loading curve B being lowest in only 2 cases. The areas of peak Von Mises stress and Principal strain also varied depending on loading curve shape and acceleration input.     

Two mitochondrial lineages occur in the Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae), in Japan

The genealogy and diversity of the mitochondrial cytochrome oxidase subunit II (COII) gene were investigated for Ostrinia furnacalis in Japan. A preliminary examination of mitochondrial lineages in China and the Philippines was also made. Two lineages (A and B) were found in the COII gene. Lineage A was frequent throughout the Japanese main islands (Hokkaido, Honshu, Shikoku and Kyushu), while the frequency of lineage B varied among these islands. No clear patterns of geographical population structure were found. Population genetic features suggested that the O. furnacalis population harboring the lineage A mitochondria expanded in the recent past, while lineage B showed weak signals of a population expansion. It is not clear whether the two lineages of mtDNA evolved in separate or identical geographical regions. We discuss two hypotheses regarding the two lineages of mtDNA: a cryptic race/species hypothesis and a selective sweep hypothesis.     

Transinfection reveals the crucial importance of Wolbachia genotypes in determining the type of reproductive alteration in the host

Wolbachia , a group of endosymbiotic bacteria in arthropods, alter the reproduction of their hosts in various ways. A Wolbachia strain (wSca) naturally infecting the adzuki bean borer moth Ostrinia scapulalis induces male killing, while another strain (wKue) infecting the Mediterranean flour moth Ephestia kuehniella induces cytoplasmic incompatibility (CI) in the resident host. Transinfection of Wolbachia can be a powerful tool to elucidate the relative importance of Wolbachia and the host in determining the type of reproductive alterations. Recently, male killing was shown to occur in E. kuehniella transinfected with w Sca. In the present study, we transferred w Kue to O. scapulalis by embryonic microinjection. In the O. scapulalis transinfected with wKue, CI, but not male killing occurred. Thus, in addition to wSca, wKue was shown to induce the same type of alteration in a foreign host as in its natural host. These results demonstrate the crucial role of the Wolbachia genotype in determining the type of reproductive alteration. However, the present study also revealed the involvement of host factors. First, the degree of incompatibility induced by wKue in O. scapulalis was stronger than that in E. kuehniella , indicating that host factors can affect the level of CI. Second, the vertical transmission rate of wKue in O. scapulalis was generally low, suggesting that the host affects the dynamics of Wolbachia transmission.     

Sexual mosaics induced by tetracycline treatment in the Wolbachia-infected adzuki bean borer, Ostrinia scapulalis.

Wolbachia-infected Ostrinia scapulalis (Lepidoptera: Crambidae) females generate all-female or nearly all-female broods. Curing the infection by tetracycline treatment during larval stages results in the generation of all-male broods in the next generation. Here we show that sexually mosaic offspring are produced by Wolbachia-infected females treated with tetracycline at the adult stage. The sexual mosaics had wings that were composed of distinctive female and male sectors. Besides wings, the sexually dimorphic mid tibiae displayed an intermediate morphology in some of the mosaics. Many of the mosaic individuals had an abnormal structure of the external genitalia as well, a combination of the male uncus and the female ovipositor. We assume that Wolbachia has a feminizing effect on O. scapulalis genetic males and, hence, incomplete curing of the Wolbachia infection results in the generation of sexually mosaic individuals.     

Sex-specific death in the Asian corn borer moth (Ostrinia furnacalis) infected with Wolbachia occurs across larval development.

Maternally inherited endosymbiotic bacteria of the genus Wolbachia induce various kinds of reproductive alterations in their arthropod hosts. In a Wolbachia-infected strain of the adzuki bean borer moth, Ostrinia scapulalis (Lepidoptera: Crambidae), males selectively die during larval development, while females selectively die when Wolbachia are eliminated by antibiotic treatment. We found that naturally occurring Wolbachia in the congener O. furnacalis caused sex-specific lethality similar to that in O. scapulalis. Cytogenetic analyses throughout the entire larval development clarified that the death of males (when infected) and females (when cured) took place mainly during early larval stages. However, some individuals also died after complete formation of larval bodies but before egg hatching, or at late larval stages, even in the penultimate instar. Although the specific timing was highly variable, death of males and females occurred before pupation without exception. The potential association of sex-specific lethality with the sex determination mechanism was also examined and is discussed.     

Upregulation of a desaturase is associated with the enhancement of cold hardiness in the onion maggot, Delia antiqua

Cold-acclimated non-diapause pupae, and summer- and winter-diapause pupae of the onion maggot, Delia antiqua (Diptera: Anthomyiidae), show marked cold hardiness as compared with intact non-diapause pupae. Homeoviscous adaptation of cellular membranes is crucial to enhance the cold hardiness of organisms, and Delta9-acyl-CoA desaturases have been assumed, albeit without experimental evidence in insects, to play a key role in the adaptation. We cloned the cDNA of a desaturase gene (Dadesat) from D. antiqua, which is most likely to encode Delta9-acyl-CoA desaturase. Expression of Dadesat mRNA in the brain, midgut, and Malpighian tubules of cold-acclimated and diapause pupae was upregulated 2-10 fold, correlating well with the increase in cold hardiness. In the pupae with enhanced cold hardiness, palmitoleic and oleic acids, the presumed products of Dadesat, in the phospholipids were significantly increased. These findings suggest that the increase in the expression of Dadesat contributes to enhanced cold hardiness in D. antiqua through the production of these unsaturated fatty acids.     

A method for rearing the yellow-spotted longicorn beetle, <Emphasis Type="Italic">Psacothea hilaris</Emphasis> (Coleoptera: Cerambycidae), to stabilize the last larval instar

The larvae of Psacothea hilaris (Pascoe) grown continuously under a long day in the laboratory pupate after the 4th, 5th, or 6th instar. This developmental polymorphism has complicated studies on the control of metamorphosis in P. hilaris. Since pupation in P. hilaris is known to be suppressed under a short day, a change in the photoperiod from a short to a long day with appropriate timing may assist in obtaining physiologically homogeneous larvae that pupate at the next molt. When the photoperiod was changed from 12-h light:12-h dark to 15-h light:9-h dark at the beginning of the 5th instar, the pupation rate at the next (5th) molt reached 90%, which was significantly higher than the proportion of larvae that pupated after the 5th instar when the larvae were grown continuously under a long day (52%). This rearing technique will expedite studies on the control of metamorphosis in P. hilaris.