Three-dimensional systolic kinematics of the right ventricle

The right ventricle (RV) of the heart is responsible for pumping blood to the lungs. Its kinematics are not as well understood as that of the left ventricle (LV) due to its thin wall and asymmetric geometry. In this study, the combination of tagged MRI and three-dimensional (3-D) image-processing techniques was used to reconstruct 3-D RV-LV motion and deformation. The reconstructed models were used to quantify the 3-D global and local deformation of the ventricles in a set of normal subjects. When compared with the LV, the RV exhibited a similar twisting pattern, a more longitudinal strain pattern, and a greater amount of displacement.     

The aluminium content of breast tissue taken from women with breast cancer

The aetiology of breast cancer is multifactorial. While there are known genetic predispositions to the disease it is probable that environmental factors are also involved. Recent research has demonstrated a regionally specific distribution of aluminium in breast tissue mastectomies while other work has suggested mechanisms whereby breast tissue aluminium might contribute towards the aetiology of breast cancer. We have looked to develop microwave digestion combined with a new form of graphite furnace atomic absorption spectrometry as a precise, accurate and reproducible method for the measurement of aluminium in breast tissue biopsies. We have used this method to test the thesis that there is a regional distribution of aluminium across the breast in women with breast cancer. Microwave digestion of whole breast tissue samples resulted in clear homogenous digests perfectly suitable for the determination of aluminium by graphite furnace atomic absorption spectrometry. The instrument detection limit for the method was 0.48 μg/L. Method blanks were used to estimate background levels of contamination of 14.80 μg/L. The mean concentration of aluminium across all tissues was 0.39 μg Al/g tissue dry wt. There were no statistically significant regionally specific differences in the content of aluminium. We have developed a robust method for the precise and accurate measurement of aluminium in human breast tissue. There are very few such data currently available in the scientific literature and they will add substantially to our understanding of any putative role of aluminium in breast cancer. While we did not observe any statistically significant differences in aluminium content across the breast it has to be emphasised that herein we measured whole breast tissue and not defatted tissue where such a distribution was previously noted. We are very confident that the method developed herein could now be used to provide accurate and reproducible data on the aluminium content in defatted tissue and oil from such tissues and thereby contribute towards our knowledge on aluminium and any role in breast cancer.     

Effects of outplanting time on growth,shedding and quality of Saccharina latissima (Phaeophyceae) in its northern distribution range

Journal of Applied Phycology - To reach the goal of large-scale seaweed cultivation in Norway and the rest of Europe, new knowledge about the commercially important kelp species Saccharina...     

Effects of basketball training on maximal oxygen uptake, muscle strength, and joint mobility in young basketball players

The purpose of this study was to examine the effects of prolonged basketball skills training on maximal aerobic power, isokinetic strength, joint mobility, and body fat percentage, in young basketball players, and controls of the same age. Twenty basketball players and 18 control boys participated in the study. Basketball players participated both in their school's physical education program and in a children's basketball team training program. Controls participated only in their school's physical education program. All subjects were tested every 6 months (18 months total, 11(1/2), 12, 12(1/2), 13 years old) for VO(2)max, peak torque values of the quadriceps and hamstrings at 180 and 300 degrees x s(-1) and range of motion of the knee and hip joints. Body fat percentage was assessed at the beginning and the end of the experimental period. Results showed that the basketball group had lower heart rate values in all ages and higher VO(2) values in the initial test compared with the control in submaximal intensity. The VO(2)max was altered in both groups on the final test, when compared to the initial test. However, the basketball group had a higher VO(2)max on each of the 6-month follow-up measurements, compared to the control group (p < 0.001). At the end of the 18-month follow-up period no significant differences were observed in isokinetic strength and joint mobility of the lower limbs between the 2 groups. On the contrary, the boys of the trained group had significantly lower percentage body fat values, compared to controls. In conclusion, regular basketball training increased aerobic power and decreased body fat percentage of prepubescent boys, while it did not affect muscle strength and joint mobility of the lower limbs. The major implication suggested by the findings of the present study is that, in order to improve the basic physical components, specific training procedures should be incorporated during the basketball training sessions. It is recommended that all children should be involved in some type of cardiovascular and resistance training program.     

Fine-Scale Distribution and Spatial Variability of Benthic Invertebrate Larvae in an Open Coastal Embayment in Nova Scotia,Canada

This study quantified the fine- scale (0.5 km) of variability in the horizontal distributions of benthic invertebrate larvae and related this variability to that in physical and biological variables, such as density, temperature, salinity, fluorescence and current velocity. Larvae were sampled in contiguous 500-m transects along two perpendicular 10-km transects with a 200-µm plankton ring net (0.75-m diameter) in St. George’s Bay, Nova Scotia, Canada, in Aug 2009. Temperature, conductivity, pressure and fluorescence were measured with a CTD cast at each station, and currents were measured with an Acoustic Doppler Current Profiler moored at the intersection of the 2 transects. Gastropod, bivalve and, to a lesser extent, bryozoan larvae had very similar spatial distributions, but the distribution of decapod larvae had a different pattern. These findings suggest that taxonomic groups with functionally similar larvae have similar dispersive properties such as distribution and spatial variability, while the opposite is true for groups with functionally dissimilar larvae. The spatial variability in larval distributions was anisotropic and matched the temporal/spatial variability in the current velocity. We postulate that in a system with no strong oceanographic features, the scale of spatially coherent physical forcing (e.g. tidal periodicity) can regulate the formation or maintenance of larval patches; however, swimming ability may modulate it.     

Can salinity-induced mortality explain larval vertical distribution with respect to a halocline?

For the larvae of two echinoderm species that coexist in Atlantic Canada (bipinnaria of the sea star Asterias rubens and 4- and 6-arm echinoplutei of the sea urchin Strongylocentrotus droebachiensis), we examined the effect of short- and long-term exposure to salinity (ranging from 18 to 35) on the probability of larval survival in laboratory experiments. We also related larval vertical distributions in response to sharp haloclines generated in the laboratory to survival probability in the salinity of different layers in the water column. For both species and developmental stages, survival probability decreased with decreasing salinity, and a salinity range of 24-27 emerged as the critical threshold for larval tolerance. The relationship between the proportion of larvae that crossed a halocline into the top water layer and the survival probability of larvae in the salinity of that layer was significant for both species. Interestingly, the shape of this response was species-specific but not stage-specific for S. droebachiensis. Our findings suggest that larval avoidance of low-salinity water layers may be an adaptive behavior that increases survival and indirectly influences larval distribution.     

Early Life History of Deep-Water Gorgonian Corals May Limit Their Abundance

Deep-water gorgonian corals are long-lived organisms found worldwide off continental margins and seamounts, usually occurring at depths of ∼200–1,000 m. Most corals undergo sexual reproduction by releasing a planktonic larval stage that disperses; however, recruitment rates and the environmental and biological factors influencing recruitment in deep-sea species are poorly known. Here, we present results from a 4-year field experiment conducted in the Gulf of Maine (northwest Atlantic) at depths >650 m that document recruitment for 2 species of deep-water gorgonian corals, Primnoa resedaeformis and Paragorgia arborea. The abundance of P. resedaeformis recruits was high, and influenced by the structural complexity of the recipient habitat, but very few recruits of P. arborea were found. We suggest that divergent reproductive modes (P. resedaeformis as a broadcast spawner and P. arborea as a brooder) may explain this pattern. Despite the high recruitment of P. resedaeformis, severe mortality early on in the benthic stage of this species may limit the abundance of adult colonies. Most recruits of this species (∼80%) were at the primary polyp stage, and less than 1% of recruits were at stage of 4 polyps or more. We propose that biological disturbance, possibly by the presence of suspension-feeding brittle stars, and limited food supply in the deep sea may cause this mortality. Our findings reinforce the vulnerability of these corals to anthropogenic disturbances, such as trawling with mobile gear, and the importance of incorporating knowledge on processes during the early life history stages in conservation decisions.     

The effect of flow on larval vertical distribution of the sea urchin, Strongylocentrotus droebachiensis

Most meroplanktonic larvae have been considered to behave as passive particles in the water column, and their dispersal determined by advection. However, larvae may influence their horizontal transport by sinking or swimming between overlying water masses. The flow conditions under which larvae influence their vertical distribution through depth regulation are presently unclear. Using an annular flume, we examined the effect of increasing flow, repeated exposure to flow, and acceleration and deceleration on the vertical distribution of 4-arm stage echinoplutei of Strongylocentrotus droebachiensis. Specifically, we generated different levels of vertical velocity and shear strengths by manipulating horizontal velocity (u). We increased and decreased flow speed incrementally from no flow (u = 0 cm s^− 1) to intermediate flow (u = 0.48 cm s^− 1) to high flow (u = 1.02 cm s^− 1) for each of 3 cycles within each of 2 independent trials. We used a high resolution digital camera to record, and image-analysis to quantify, larval distribution. In the absence of flow, larvae swam upwards and aggregated near the surface of the flume. With increasing flow, increasing numbers of larvae were observed in the mid to low water column indicating a negative influence on larval ability to aggregate near the surface. No differences were observed between distributions in acceleration and deceleration phases of the cycles; however, results suggest that increased exposure can decrease the ability of larvae to regulate their vertical position over time. Vertical shear can result in the re-orientation of swimming larvae and likely compromised larval ability for directed swimming in our study. The threshold shear level beyond which larvae cannot regulate their vertical position is > 2 s^− 1, suggesting that echinoid larvae may be more vulnerable to shear than other weak swimmers, most likely because of their shape. However, echinoid larvae can likely influence their vertical distribution within many areas in the ocean, since shears > 2 s^− 1 are present only in highly turbulent regions such as fronts.