[1] Chlorate (ClO 3 À ) is an intermediate oxidation species between chloride (Cl À ) and perchlorate (ClO 4 À ), both of which were found at the landing site by the Wet Chemistry Lab (WCL). The chlorate ion is almost as stable as perchlorate, and appears to be associated with perchlorate in most terrestrial reservoirs (e.g. Atacama and Antarctica). It is possible that chlorate contributed to the ion sensor response on the WCL, yet was masked by the strong perchlorate signal. However, very little is known about chlorate salts and their effect on the stability of water. We performed evaporation rate experiments in our Mars simulation chamber, which enabled us to determine the activity of water for various concentrations. From this we constructed solubility diagrams for NaClO 3 , KClO 3 , Mg(ClO 3 ) 2 and Ca(ClO 3 ) 2 , and determined the Pitzer parameters for each salt. Chlorate salt eutectic temperatures range from 270 K (KClO 3 ) to 204 K (Mg(ClO 3 ) 2 ). Modeling the addition of chlorate to the initial WCL solutions shows that it precipitates in concentrations comparable to other common salts, such as gypsum and epsomite, and implies that chlorates may play an important role in the wet chemistry on Mars. Citation: Hanley, J

Electrical and chemical stimulation have been studied as potent mechanisms of enhancing nerve regeneration and wound healing. However, it remains unclear how electrical stimuli affect nerve growth, particularly in the presence of neurotrophic factors. The objective of this study was to explore (1) the effect of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) supplementation to support neurite outgrowth in a 3D scaffold, and (2) the effect of brief, low voltage, electrical stimulation (ES) on neurite outgrowth prior to neurotrophin supplementation. Dissociated E11 chick dorsal root ganglia (DRG) were seeded within a 1.5 mg/mL type-I collagen scaffold. For neurotrophin treatments, scaffolds were incubated for 24 hrs in culture media containing nerve growth factor (NGF, 10 ng/mL) or BDNF (200 ng/mL), or both. For ES groups, scaffolds containing neurons were stimulated for 10 min at 8–10 V/m DC, then incubated for 24 hrs with neurotrophin. Fixed and labeled neurons were imaged to measure neurite growth and directionality. BDNF supplementation was not as effective as NGF at supporting DRG neurite outgrowth. ES prior to NGF supplementation improved DRG neurite outgrowth compared to NGF alone. This combination of brief ES with NGF treatment was the most effective treatment compared to NGF or BDNF alone. Brief ES had no impact on neurite directionality in the 3D scaffolds. These results demonstrate that ES improves neurite outgrowth in the presence of neurotrophins, and could provide a potential therapeutic approach to improve nerve regeneration when coupled with neurotrophin treatment.

Adult sea lamprey Petromyzon marinus attachment strength by the oral sucker was quantified. Surfaces with shallow, rounded discontinuities into which the oral fimbriae could be folded yielded the strongest seal and some fish could control their mouths to improve 'suction'. Narrow grooves of 1 mm width and 3 mm depth prevented P. marinus from creating a lasting attachment.This study examined the physical characteristics of 'suction' attachment in spawning-run sea lampreys Petromyzon marinus L. Throughout the paper, the term 'suction' refers to the interaction between the low pressure in P. marinus oral cavity and the higher external water pressure, which enables P. marinus to adhere to a surface. Oral disc pressures were characterized during attachments to acrylic surfaces cut with surface intrusions that varied in area and shape. Grooves were selected to simulate these surface discontinuities, as they are easily generated in a quantifiable fashion. The areas and shapes of grooves were carefully chosen to provide an estimated range of attachment ability that would be recognizable through pressure characteristic analysis. Additionally, an analysis of oral disc contortion on the varying grooved surfaces evaluated the importance of the flexibility of the oral disc and fimbriae (Lethbridge & Potter, 1979;Khidir & Renaud, 2003). Results from this study may benefit researchers examining migratory behaviour of P. marinus, specifically those interested in enhancing or blocking upstream movement.One hundred and twenty P. marinus were trapped in the Ocqueoc River (45°059 N; 84°009 W) in mid-May 2005 (mean total length, L T , 467 mm, range

In many instances of extensive nerve damage, the injured nerve never adequately heals, leaving lack of nerve function. Electrical stimulation (ES) has been shown to increase the rate and orient the direction of neurite growth, and is a promising therapy. However, the mechanism in which ES affects neuronal growth is not understood, making it difficult to compare existing ES protocols or to design and optimize new protocols. We hypothesize that ES acts by elevating intracellular calcium concentration ([Ca(2+)]i) via opening voltage-dependent Ca(2+) channels (VDCCs). In this work, we have created a computer model to estimate the ES Ca(2+) relationship. Using COMSOL Multiphysics, we modeled a small dorsal root ganglion (DRG) neuron that includes one Na(+) channel, two K(+) channels, and three VDCCs to estimate [Ca(2+)]i in the soma and growth cone. As expected, the results show that an ES that generates action potentials (APs) can efficiently raise the [Ca(2+)]i of neurons. More interestingly, our simulation results show that sub-AP ES can efficiently raise neuronal [Ca(2+)]i and that specific high-voltage ES can preferentially raise [Ca(2+)]i in the growth cone. The intensities and durations of ES on modeled growth cone calcium rise are consistent with directionality and orientation of growth cones experimentally shown by others. Finally, this model provides a basis to design experimental ES pulse parameters, including duration, intensity, pulse-train frequency, and pulse-train duration to efficiently raise [Ca(2+)]i in neuronal somas or growth cones.

Overfishing, bycatch, and habitat loss and alteration during the late 19th century to the end of the 20th century caused significant declines in Atlantic Sturgeon Acipenser oxyrinchus stock abundances along the Atlantic coast. To prevent further stock reductions, a coastwide harvest moratorium was implemented in 1998. With fishery‐dependent data unavailable to inform stock management, fishery‐independent surveys contribute vital information for monitoring population trends by providing data for evaluating the effectiveness of the moratorium and for informing recovery planning. In 2004, a standardized monitoring survey was developed to assess trends in the relative abundance of juvenile Atlantic Sturgeon in the Hudson River, New York. The multimesh anchored gill‐net survey randomly sampled locations in soft, deep depositional areas of Haverstraw Bay from late February through early May. Predicted length‐at‐age relationships were used to infer annual age structure and to examine the relationships between age and annual catch rates. Generalized additive regression modeling was used to describe the relationships between the environmental variables and catch rates and to standardize the abundance index to account for variability in environmental conditions over time. Atlantic Sturgeon catch rates generally increased with increasing water temperature and salinity, and the standardized abundance index (accounting for environmental variability) was highly correlated with the nominal abundance index. In the 16 years of annual monitoring, there has been a significant increase in the relative abundance of juvenile Atlantic Sturgeon. The average catch rate in recent years (2012–2019) is more than twice that observed during the first 8 years (2004–2011) of the survey, as the effects of the moratorium are expected to be delayed due to the long maturation period of Atlantic Sturgeon. These trends suggest that juvenile Atlantic Sturgeon in the Hudson River may be recovering in response to the moratorium and demonstrate the need for long‐term fisheries‐independent monitoring to document abundance trends in slow‐maturing, long‐lived species.