An improved system to measure leaf gas exchange on adaxial and abaxial surfaces

Measurement of leaf carbon gain and water loss (gas exchange) in planta is a standard procedure in plant science research for attempting to understand physiological traits related to water use and photosynthesis. Leaves carry out gas exchange through the upper (adaxial) and lower (abaxial) surfaces at different magnitudes, depending on the stomatal density, stomatal aperture, cuticular permeability, etc., of each surface, which we account for in gas exchange parameters such as stomatal conductance. Most commercial devices measure leaf gas exchange by combining the adaxial and abaxial fluxes and calculating bulk gas exchange parameters, missing details of the plant's physiological response on each side. Additionally, the widely used equations to estimate gas exchange parameters neglect the contribution of small fluxes such as cuticular conductance, adding extra uncertainties to measurements performed in water-stress or low-light conditions. Accounting for the gas exchange fluxes from each side of the leaf allows us to better describe plants' physiological traits under different environmental conditions and account for genetic variability. Here, apparatus and materials are presented for adapting two LI-6800 Portable Photosynthesis Systems to work as one gas exchange system to measure adaxial and abaxial gas exchange simultaneously. The modification includes a template script with the equations to account for small fluxes. Instructions are provided for incorporating the add-on script into the device's computational sequence, display, variables, and spreadsheet results. We explain the method to obtain an equation to estimate boundary layer conductance to water for the new setup and how to embed this equation in the devices' calculations using the provided add-on script. The apparatus, methods, and protocols presented here provide a simple adaptation combining two LI-6800s to obtain an improved system to measure leaf gas exchange on adaxial and abaxial surfaces

Integrating Trust into the CyberCraft Initiative via the Trust Vectors Model

This research supports the hypothesis that the Trust Vector model can be modified to fit the CyberCraft Initiative, and that there are limits to the utility of historical data. This research proposed some modifications and expansions to the Trust Model Vector, and identified areas for future research

Assessing the CO2 concentration at the surface of photosynthetic mesophyll cells

We present a robust estimation of the CO2 concentration at the surface of photosynthetic mesophyll cells (cw), applicable under reasonable assumptions of assimilation distribution within the leaf. We used Capsicum annuum, Helianthus annuus and Gossypium hirsutumas model plants for our experiments. We introduce calculations to estimate cw using independent adaxial and abaxial gas exchange measurements, and accounting for the mesophyll airspace resistances. The cw was lower than adaxial and abaxial estimated intercellular CO2 concentrations (ci). Differences between cw and the ci of each surface were usually larger than 10 μmol mol−1. Differences between adaxial and abaxial ci ranged from a few μmol mol−1 to almost 50 μmol mol−1, where the largest differences were found at high air saturation deficits (ASD). Differences between adaxial and abaxial ci and the ci estimated by mixing both fluxes ranged from −30 to +20 μmol mol−1, where the largest differences were found under high ASD or high ambient CO2 concentrations. Accounting for cw improves the information that can be extracted from gas exchange experiments, allowing a more detailed description of the CO2 and water vapor gradients within the leaf

A Canine Model to Assess the Biochemical Stress Response to Laparoscopic and Open Surgery

Purpose: To develop an animal model to assess the stress response to open and laparoscopic surgery. Such a model would allow objective physiologic assessment of the putative benefits of laparoscopy and provide a framework in which to compare modifications in operative and anesthetic technique that might decrease the stress of surgery. Materials and Methods: Mongrel dogs underwent laparoscopic (N = 12) or open surgical (N = 12) left nephrectomy. In 11 control animals, after induction of anesthesia and line placement, the animal underwent either no intervention (open surgery sham; N = 6) or pneumoperitoneum only (laparoscopic sham; N = 5). Serum glucose and cortisol were measured preoperatively, at skin closure, and at 4, 8, and 24 hours postoperatively. Values at each time point were compared in the laparoscopic and open surgical nephrectomy groups and in each of the two nephrectomy groups and their respective shams. Results: Compared with baseline, there was a sharp rise in serum cortisol at the time of skin closure, with a gradual decline to baseline values by 24 hours, in all experimental animals. Significantly lower serum cortisol concentrations were seen at 4 and 8 hours postoperatively in the laparoscopic group than in the open surgery group. Cortisol was significantly higher in the open group than in the sham-open group at all time points, whereas cortisol was greater in the laparoscopic group than in the pneumoperitoneum-only group only at the 4-hour time point. No differences were seen in serum glucose between groups. Conclusions: The serum cortisol concentration appears to be a good measure of surgical stress in the canine model. The rapid decline in serum cortisol after laparoscopy compared with open surgery may indicate a lesser degree, or quicker resolution, of surgical stress in the former. Furthermore, the similarity in cortisol curves between laparoscopy and pneumoperitoneum only suggests that surgical stress in laparoscopic surgery may be attributable mainly to the effects of pneumoperitoneum.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63212/1/089277901317203100.pd

Improved Efficacy of a Gene Optimised Adenovirus-based Vaccine for Venezuelan Equine Encephalitis Virus

<p>Abstract</p> <p>Background</p> <p>Optimisation of genes has been shown to be beneficial for expression of proteins in a range of applications. Optimisation has increased protein expression levels through improved codon usage of the genes and an increase in levels of messenger RNA. We have applied this to an adenovirus (ad)-based vaccine encoding structural proteins (E3-E2-6K) of Venezuelan equine encephalitis virus (VEEV).</p> <p>Results</p> <p>Following administration of this vaccine to Balb/c mice, an approximately ten-fold increase in antibody response was elicited and increased protective efficacy compared to an ad-based vaccine containing non-optimised genes was observed after challenge.</p> <p>Conclusion</p> <p>This study, in which the utility of optimising genes encoding the structural proteins of VEEV is demonstrated for the first time, informs us that including optimised genes in gene-based vaccines for VEEV is essential to obtain maximum immunogenicity and protective efficacy.</p

High g-Force Rollercoaster Rides Induce Sinus Tachycardia but No Cardiac Arrhythmias in Healthy Children

This is the final version of the article. Available from Springer Verlag via the DOI in this record.Theme park operators and medical professionals advise children with heart conditions against using rollercoaster rides, but these recommendations are not evidence-based. The underlying assumption is that the combination of adrenergic stimulation through stress and acceleration might trigger arrhythmias in susceptible individuals. We conducted a cross-sectional observational study to assess heart rate and rhythm in healthy children during commercial rollercoaster rides. Twenty healthy children (9 male) aged 11-15 (mean 13.3 ± 1.4) years underwent continuous heart rate and rhythm monitoring (2-lead ECG) from 5 min before until 10 min after each of 4 high speed (>50 km h(-1)), high g-force (>4) commercial rollercoaster rides. Total recording time was 13 h 20 min. No arrhythmic events were detected. Resting heart rate was 81 ± 10 b min(-1) and increased to 158 ± 20 b·min(-1) during rides. The highest mean HR (165 ± 23 b min(-1)) was observed on the ride with the lowest g-force (4.5 g), but one of the highest speeds (100 km h(-1)). Anticipatory tachycardia (126 ± 15 b min(-1)) within 5 min was frequently observed. A 10 min recovery HR (124 ± 17 b min(-1)) was 56 % greater than resting HR. The speed and g-force experienced on roller coasters induce sinus tachycardia but do not elicit pathological arrhythmias in healthy children.This work was supported by the National Institute for Health Research (NIHR) Biomedical Research Unit in Cardiovascular Disease at the University Hospitals Bristol NHS Foundation Trust and the University of Bristol. Dr Pieles is the holder of an NIHR Academic Clinical Lectureship in Paediatric Cardiology. We would like to thank Novacor Ltd (Swanley, Kent, UK) for providing portable ECG monitoring equipment and Thorpe Park (Merlin Entertainments PLC, Poole, Dorset, UK) for their support during data acquisition. We thank all of the children and their families for participating in this study

The 20 GHz circularly polarized, high temperature superconducting microstrip antenna array

The primary goal was to design and characterize a four-element, 20 GHz, circularly polarized microstrip patch antenna fabricated from YBa2Cu3O(x) superconductor. The purpose is to support a high temperature superconductivity flight communications experiment between the space shuttle orbiter and the ACTS satellite. This study is intended to provide information into the design, construction, and feasibility of a circularly polarized superconducting 20 GHz downlink or cross-link antenna. We have demonstrated that significant gain improvements can be realized by using superconducting materials for large corporate fed array antennas. In addition, we have shown that when constructed from superconducting materials, the efficiency, and therefore the gain, of microstrip patches increases if the substrate is not so thick that the dominant loss mechanism for the patch is radiation into the surface waves of the conductor-backed substrate. We have considered two design configurations for a superconducting 20 GHz four-element circularly polarized microstrip antenna array. The first is the Huang array that uses properly oriented and phased linearly polarized microstrip patch elements to realize a circularly polarized pattern. The second is a gap-coupled array of circularly polarized elements. In this study we determined that although the Huang array operates well on low dielectric constant substrates, its performance becomes extremely sensitive to mismatches, interelement coupling, and design imperfections for substrates with high dielectric constants. For the gap-coupled microstrip array, we were able to fabricate and test circularly polarized elements and four-element arrays on LaAlO3 using sputtered copper films. These antennas were found to perform well, with relatively good circular polarization. In addition, we realized a four-element YBa2Cu3O(x) array of the same design and measured its pattern and gain relative to a room temperature copper array. The patterns were essentially the same as that for the copper array. The measured gain of the YBCO antenna was greater than that for the room temperature copper design at temperatures below 82K, reaching a value of 3.4 dB at the lowest temperatures

Modelling the response of surface fuel to climate change across south-eastern Australia: consequences for future fire regimes

Geophysical Research Abstracts of EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria