Use of a Novel Cell Adhesion Method and Digital Measurement to Show Stimulus‐dependent Variation in Somatic and Oral Ciliary Beat Frequency in Paramecium

When Paramecium encounters positive stimuli, the membrane hyperpolarizes and ciliary beat frequency increases. We adapted an established immobilization protocol using a biological adhesive and a novel digital analysis system to quantify beat frequency in immobilized Paramecium. Cells showed low mortality and demonstrated beat frequencies consistent with previous studies. Chemoattractant molecules, reduction in external potassium, and posterior stimulation all increased somatic beat frequency. In all cases, the oral groove cilia maintained a higher beat frequency than mid‐body cilia, but only oral cilia from cells stimulated with chemoattactants showed an increase from basal levels.     

Pectoral fin beat frequency predicts oxygen consumption during spontaneous activity in a labriform swimming fish (Embiotoca lateralis)

The objective of this study was to identify kinematic variables correlated with oxygen consumption during spontaneous labriform swimming. Kinematic variables (swimming speed, change of speed, turning angle, turning rate, turning radius and pectoral fin beat frequency) and oxygen consumption (MO₂) of spontaneous swimming in Embiotoca lateralis were measured in a circular arena using video tracking and respirometry, respectively. The main variable influencing MO₂ was pectoral fin beat frequency (r ² = 0.71). No significant relationship was found between swimming speed and pectoral fin beat frequency. Complementary to other methods within biotelemetry such as EMG it is suggested that such correlations of pectoral fin beat frequency may be used to measure the energy requirements of labriform swimming fish such as E. lateralis in the field, but need to be taken with great caution since movement and oxygen consumption patterns are likely to be quite different in field situation compared to a small lab tank. In addition, our methods could be useful to measure metabolic costs of growth and development, or bioassays for possible toxicological effects on fish.     

Slight mistuning of a cryogenic probe significantly perturbs the water <Superscript>1</Superscript>H precession frequency

A shift of the water proton precession frequency is described that can introduce errors in chemical shifts derived using the water signal as the chemical shift reference. This shift, f_s, arises as a consequence of radiation damping when the water proton and detector circuit resonance frequencies differ. Herein it is shown that experimental values of f_s, measured as a function of detector circuit tuning offset for 500 and 900 MHz cryogenic probes, are in good agreement with theory. Of importance is the fact that even a small degree of mistuning, which does not significantly impact the performance of a pulse sequence, introduces chemical shift errors of ±0.03 ppm, that negatively impact many types of experiments. A simple remedy that attenuates the frequency shift is presented.     

Herd-scale measurements of methane emissions from cattle grazing extensive sub-tropical grasslands using the open-path laser technique

Methane (CH₄) emissions associated with beef production systems in northern Australia are yet to be quantified. Methodologies are available to measure emissions, but application in extensive grazing environments is challenging. A micrometeorological methodology for estimating herd-scale emissions using an indirect open-path spectroscopic technique and an atmospheric dispersion model is described. The methodology was deployed on five cattle properties across Queensland and Northern Territory, with measurements conducted during two occasions at one site. On each deployment, data were collected every 10 min for up to 7 h a day over 4 to 16 days. To increase the atmospheric concentration of CH₄ to measurable levels, cattle were confined to a known area around water points from ~0800 to 1600 h, during which time measurements of wind statistics and line-averaged CH₄ concentration were taken. Filtering to remove erroneous data accounted for 35% of total observations. For five of the six deployments CH₄ emissions were within the expected range of 0.4 to 0.6 g/kg BW. At one site, emissions were ~2 times expected values. There was small but consistent variation with time of day, although for some deployments measurements taken early in the day tended to be higher than at the other times. There was a weak linear relationship (R²=0.47) between animal BW and CH₄ emission per kg BW. Where it was possible to compare emissions in the early and late dry season at one site, it was speculated that higher emissions at the late dry season may have been attributed to poorer diet quality. It is concluded that the micrometeorological methodology using open-path lasers can be successfully deployed in extensive grazing conditions to directly measure CH₄ emissions from cattle at a herd scale.     

Experimental study of bremsstrahlung and characteristic radiation spectra from laser targets irradiated with ultrashort laser pulses with intensities of up to ∼1019 W/cm2

Results from experimental studies of bremsstrahlung and characteristic radiation spectra from laser targets irradiated with ultrashort laser pulses with intensities of up to ～10¹⁹ W/cm² are presented. The continuous spectra of hard X-ray emission from Ta and Al targets and the line spectrum of copper were measured. The temperature of fast electrons was obtained from the measured hard X-ray spectra, and the K_α radiation yield from Ta was measured. The energy conversion efficiency of laser radiation into the copper characteristic radiation was obtained from the measured yield of K_α radiation.     

Estimating fish swimming metrics and metabolic rates with accelerometers: the influence of sampling frequency

Accelerometry is growing in popularity for remotely measuring fish swimming metrics, but appropriate sampling frequencies for accurately measuring these metrics are not well studied. This research examined the influence of sampling frequency (1–25 Hz) with tri‐axial accelerometer biologgers on estimates of overall dynamic body acceleration (ODBA), tail‐beat frequency, swimming speed and metabolic rate of bonefish Albula vulpes in a swim‐tunnel respirometer and free‐swimming in a wetland mesocosm. In the swim tunnel, sampling frequencies of ≥ 5 Hz were sufficient to establish strong relationships between ODBA, swimming speed and metabolic rate. However, in free‐swimming bonefish, estimates of metabolic rate were more variable below 10 Hz. Sampling frequencies should be at least twice the maximum tail‐beat frequency to estimate this metric effectively, which is generally higher than those required to estimate ODBA, swimming speed and metabolic rate. While optimal sampling frequency probably varies among species due to tail‐beat frequency and swimming style, this study provides a reference point with a medium body‐sized sub‐carangiform teleost fish, enabling researchers to measure these metrics effectively and maximize study duration.     

Flight modes in migrating European bee-eaters: heart rate may indicate low metabolic rate during soaring and gliding

Background

Many avian species soar and glide over land. Evidence from large birds (m _b>0.9 kg) suggests that soaring-gliding is considerably cheaper in terms of energy than flapping flight, and costs about two to three times the basal metabolic rate (BMR). Yet, soaring-gliding is considered unfavorable for small birds because migration speed in small birds during soaring-gliding is believed to be lower than that of flapping flight. Nevertheless, several small bird species routinely soar and glide.

Methodology/Principal Findings

To estimate the energetic cost of soaring-gliding flight in small birds, we measured heart beat frequencies of free-ranging migrating European bee-eaters (Merops apiaster, m _b∼55 g) using radio telemetry, and established the relationship between heart beat frequency and metabolic rate (by indirect calorimetry) in the laboratory. Heart beat frequency during sustained soaring-gliding was 2.2 to 2.5 times lower than during flapping flight, but similar to, and not significantly different from, that measured in resting birds. We estimated that soaring-gliding metabolic rate of European bee-eaters is about twice their basal metabolic rate (BMR), which is similar to the value estimated in the black-browed albatross Thalassarche (previously Diomedea) melanophrys, m _b∼4 kg). We found that soaring-gliding migration speed is not significantly different from flapping migration speed.

Conclusions/Significance

We found no evidence that soaring-gliding speed is slower than flapping flight in bee-eaters, contradicting earlier estimates that implied a migration speed penalty for using soaring-gliding rather than flapping flight. Moreover, we suggest that small birds soar and glide during migration, breeding, dispersal, and other stages in their annual cycle because it may entail a low energy cost of transport. We propose that the energy cost of soaring-gliding may be proportional to BMR regardless of bird size, as theoretically deduced by earlier studies.     

TiO2 Nanocrystals Synthesized by Laser Pyrolysis for the Up‐Scaling of Efficient Solid‐State Dye‐Sensitized Solar Cells

A crucial issue regarding emerging nanotechnologies remains the up‐scaling of new functional nanostructured materials towards their implementation in high performance applications on a large scale. In this context, we demonstrate high efficiency solid‐state dye‐sensitized solar cells prepared from new porous TiO₂ photoanodes based on laser pyrolysis nanocrystals. This strategy exploits a reduced number of processing steps as well as non‐toxic chemical compounds to demonstrate highly porous TiO₂ films. The possibility to easily tune the TiO₂ nanocrystal physical properties allows us to demonstrate all solid‐state dye‐sensitized devices based on a commercial benchmark materials (organic indoline dye and molecular hole transporter) presenting state‐of‐the‐art performance comparable with reference devices based on a commercial TiO₂ paste. In particular, a drastic improvement in pore infiltration, which is found to balance a relatively lower surface area compared to the reference electrode, is evidenced using laser‐synthesized nanocrystals resulting in an improved short‐circuit current density under full sunlight. Transient photovoltage decay measurements suggest that charge recombination kinetics still limit device performance. However, the proposed strategy emphasizes the potentialities of the laser pyrolysis technique for up‐scaling nanoporous TiO₂ electrodes for various applications, especially for solar energy conversion.     

Moderate precipitation reduction enhances nitrogen cycling and soil nitrous oxide emissions in a semi-arid grassland

The ongoing climate change is predicted to induce more weather extremes such as frequent drought and high-intensity precipitation events, causing more severe drying-rewetting cycles in soil. However, it remains largely unknown how these changes will affect soil nitrogen (N)-cycling microbes and the emissions of potent greenhouse gas nitrous oxide (N₂O). Utilizing a field precipitation manipulation in a semi-arid grassland on the Loess Plateau, we examined how precipitation reduction (ca. −30%) influenced soil N₂O and carbon dioxide (CO₂) emissions in field, and in a complementary lab-incubation with simulated drying-rewetting cycles. Results obtained showed that precipitation reduction stimulated plant root turnover and N-cycling processes, enhancing soil N₂O and CO₂ emissions in field, particularly after each rainfall event. Also, high-resolution isotopic analyses revealed that field soil N₂O emissions primarily originated from nitrification process. The incubation experiment further showed that in field soils under precipitation reduction, drying-rewetting stimulated N mineralization and ammonia-oxidizing bacteria in favor of genera Nitrosospira and Nitrosovibrio, increasing nitrification and N₂O emissions. These findings suggest that moderate precipitation reduction, accompanied with changes in drying-rewetting cycles under future precipitation scenarios, may enhance N cycling processes and soil N₂O emissions in semi-arid ecosystems, feeding positively back to the ongoing climate change.     

Rapid relaxation processes in pig heart lipoamide dehydrogenase revealed by subnanosecond resolved fluorometry

The decay kinetics of the FAD-fluorescence in lipoamide dehydrogenase from pig heart have been reinvestigated using phase fluorometric methods and sophisticated laser pulse techniques. Both pulse and modulation methods lead to distinct heterogeneity in lifetimes. The two different techniques lead to good correspondence in the longer lifetime component of a biexponential decay model, whereas the more rapidly decaying component is distinctly shorter and has a larger amplitude using the phase technique with two available modulation frequencies (15 and 60 MHz). Lifetime measurements as a function of temperature and in the presence of D₂O instead of H₂O illustrate that the quenching of the FAD fluorescence in lipoamide. dehydrogenase is mainly dynamic in nature and that solvent comes into contact with the fluorophor. Mobility of the flavin itself, free and bound to the enzyme, has been measured by both differential polarized phase fluorometry and experimental fluorescence anisotropy decay after ps laser pulse excitation. By employing flavin models it has been shown that both techniques have ps time resolution. Measurements with the latter more direct method indicate a rapid subnanosecond motion of the FAD bound within the enzyme, only visible at temperatures lower than about 15°C, where the protein rotational diffusion is slowed down. The significance of rapid transient conformational fluctuations for catalysis is discussed with reference to recently developed insights reported in the literature.     

Four-frequency polarizing microscope for recording plasma images in the wavelength range 0.4–1.1 μm

The optical scheme and design of a four-frequency polarizing microscope intended for simultaneous recording of plasma images in the wavelength range 0.4–1.1 μm with the spatial resolution 12 μm in the entire spectral range are described. The effectiveness of such a microscope in studies of plasmas produced on interaction of laser radiation with a target is demonstrated. The plasma images are obtained at the frequencies ω₀, (3/2)ω₀, 2ω₀, and (5/2)ω₀, where ω₀ corresponds to the frequency of heating radiation. The transformation coefficient that characterizes the efficiency of conversion of heating radiation into the 2ω₀, (3/2)ω₀, and (5/2)ω₀ harmonics generated in the plasma is determined.     

Variation in enteric methane emissions among cows on commercial dairy farms

Methane (CH₄) emissions by dairy cows vary with feed intake and diet composition. Even when fed on the same diet at the same intake, however, variation between cows in CH₄ emissions can be substantial. The extent of variation in CH₄ emissions among dairy cows on commercial farms is unknown, but developments in methodology now permit quantification of CH₄ emissions by individual cows under commercial conditions. The aim of this research was to assess variation among cows in emissions of eructed CH₄ during milking on commercial dairy farms. Enteric CH₄ emissions from 1964 individual cows across 21 farms were measured for at least 7 days/cow using CH₄ analysers at robotic milking stations. Cows were predominantly of Holstein Friesian breed and remained on the same feeding systems during sampling. Effects of explanatory variables on average CH₄ emissions per individual cow were assessed by fitting a linear mixed model. Significant effects were found for week of lactation, daily milk yield and farm. The effect of milk yield on CH₄ emissions varied among farms. Considerable variation in CH₄ emissions was observed among cows after adjusting for fixed and random effects, with the CV ranging from 22% to 67% within farms. This study confirms that enteric CH₄ emissions vary among cows on commercial farms, suggesting that there is considerable scope for selecting individual cows and management systems with reduced emissions.     

A Radiation Hybrid Map of 95 STSs Spanning Human Chromosome 13q

We have constructed a high-resolution physical map of the long arm of human chromosome 13 using a panel of 94 radiation hybrids. A comprehensive map of 95 chromosome 13-specific sequence tagged sites (STSs) spanning 13q from the presumed centromere at D13Z1 to the known telomere was obtained by multipoint maximum likelihood statistical methods. The 95 markers have an average retention frequency of 10%, with markers closer to the centromere having much greater retention frequencies (22-49%) than distal 13q markers (2-12%) The most likely radiation hybrid map localized the 95 STSs into 54 unique map positions, 34 with odds of 1000:1 or greater; the comprehensive map localized all but 17 STSs with odds exceeding 10:1. The total map length of 13q was 1302 cR₉₀₀₀ (range 6.4-94.4 cR₉₀₀₀) and a physical distance of 98 Mb, so that 1% breakage in the RH panel corresponds to 75 kb. A comparison of the comprehensive RH map to genetic maps of chromosome 13q shows identical locus orders for the common markers, with two exceptions over 1-cM distances. We discuss the possible relationships between the genetic and the radiation hybrid maps.     

Taking Temperature Processing Out of Dye‐Sensitized Solar Cell Fabrication: Fully Laser‐Manufactured Devices

Novel approaches for the fabrication of dye‐sensitized solar cells (DSCs) are reported in which all the main constituent materials are processed by laser radiation. In addition to laser sintering of the nanocrystalline TiO₂ film it is shown that lasers can be successfully utilized for nc‐TiO₂ film patterning, platinization of the counter‐electrode, and efficient gasket sealing. All the mentioned processes are optimized and utilized for the fabrication of the first efficient and durable all‐laser‐based DSCs. Under one sun A.M. 1.5 illumination the power conversion efficiency (PCE) is 5.3% (6.2% unmasked) and also greater than or equal to the PCE of the cell fabricated with the same materials set but processed using conventional procedures (5.2%). These results open up a new scenario for DSC technology, i.e., that of setting up an entire, laser‐based, three‐step DSC pilot production line with tangible advantages in terms of effective processing, automation, large area scalability, and embedded energy.     

Swimming in the sea hare Aplysia brasiliana: Cost of transport, parapodial morphometry, and swimming behavior

The energetics and behavior of the parapodial-swimming Aplysia brasiliana were investigated in order to compare net cost of transport (COT_net) between swimming and crawling, and to compare transport costs with other swimmers. Oxygen consumption (V_O2) increased with increasing animal mass for resting, crawling, and swimming animals. Slopes of the regressions of log V_O2 on log mass were 0.90, 0.91, and 0.89 for resting, crawling, and swimming, respectively. The regression for resting V_O2 on mass was significantly lower than regressions of crawling and swimming on mass, which fell into a statistically homogenous subgroup. During 4-h swimming bouts, parapodial beat frequency dropped by less than 10% of starting values after 2 h and then stabilized for the remainder of the trial, whereas velocity steadily decreased to about 70% of starting values over the 4-h period. Initial beat frequency (at the start of a swimming bout) was negatively related to body mass, varying from 1.1 beat s^− 1 for a 34 g individual to 0.7 beats s^− 1 for a 500 g individual. Final beat frequency (at the end of a swimming bout) was also negatively related to body mass, but had a significantly lower intercept than initial beat frequency. Neither initial swimming velocity nor final swimming velocity was related to mass, but final velocity was significantly lower than initial velocity. A 250 g A. brasiliana swam at 345 m h^− 1 and crawled at 7 m h^− 1. Swimming COT_net (0.1 ml O₂ kg^− 1 m^− 1) for a 250 g A. brasiliana was 50 times less than crawling COT_net (5.3 ml O₂ kg^− 1 m^− 1). While the crawling COT_net for A. brasiliana fell within the range of other marine gastropods, swimming COT_net was less than that of swimming crustaceans, and much less than another gastropod, Melibe leonina, that uses lateral bending to swim.     

Fluxes of nitrous oxide and methane on an abandoned peat extraction site: Effect of reed canary grass cultivation

Drained organic soils are among the most risky soil types as far as their greenhouse gas emissions are considered. Reed canary grass (RCG) is a potential bioenergy crop in the boreal region, but the atmospheric impact of its cultivation is unknown. The fluxes of N₂O and CH₄ were measured from an abandoned peat extraction site (an organic soil) cultivated with RCG using static chamber and snow gradient techniques. The fluxes were measured also at an adjacent site which is under active peat extraction and it is devoid of any vegetation (BP site). The 4-year average annual N₂O emissions were low being 0.1 and 0.01 g N₂O m⁻² a⁻¹ at the RCG and BP sites, respectively. The corresponding mean annual CH₄ emissions from the RCG and BP sites were also low (0.4 g and 0.9 g CH₄ m⁻² a⁻¹). These results highlight for the first time that there are organic soils where cultivation of perennial bioenergy crops is possible with low N₂O and CH₄ emissions.     

Size,temperature, and scaphognathite frequency-dependent variations of ventilation volumes in Carcinus maenas (L.)

There is a direct, linear relationship between scaphognathie beat frequency and absolute ventilation volume in Carcinus maenas (L). The absolute ventilation volume is directly proportional to the size of the animals. At all scaphognathie frequencies small animals have a greater relative ventilation volume than large animals. The absolute stroke volume (ml/beat) is greater in large animals than in small animals. The majority of the available evidence suggests that, whilst the force of the scaphognathie stroke may be variable, the amplitude of its excursion remains constant at all beat frequencies.     

Rapid,controllable, one‐pot and room‐temperature aqueous synthesis of ZnO:Cu nanoparticles by pulsed UV laser and its application for photocatalytic degradation of methyl orange

Zinc oxide (ZnO) and ZnO:Cu nanoparticles (NPs) were synthesized using a rapid, controllable, one‐pot and room‐temperature pulsed UV‐laser assisted method. UV‐laser irradiation was used as an effective energy source in order to gain better control over the NPs size and morphology in aqueous media. Parameters effective in laser assisted synthesis of NPs such as irradiation time and laser shot repetition rate were optimized. Photoluminescence (PL) spectra of ZnO NPs showed a broad emission with two trap state peaks located at 442 and 485 nm related to electronic transition from zinc interstitial level (I_Zn) to zinc vacancy level (V_Zn) and electronic transition from conduction band to the oxygen vacancy level (V_O), respectively. For ZnO:Cu NPs, trap state emissions disappeared completely and a copper (Cu)‐related emission appeared. PL intensity of Cu‐related emission increased with the increase in concentration of Cu²⁺, so that for molar ratio of Cu:Zn 2%, optimal value of PL intensity was obtained. The photocatalytic activity of Cu‐doped ZnO revealed 50 and 100% increasement than that of undoped NPs under UV and visible irradiation, respectively. The enhanced photocatalytic activity could be attributed to smaller crystal size, as well as creation of impurity acceptor levels (T₂) inside the ZnO energy band gap.     

A quantitative evaluation of the use of medical lasers in German hospitals

The laser has become an integral part of modern medicine, procedures based on this technique have found their way into a multitude of medical disciplines. There is, however, no data available on the detailed quantitative development of laser use in the medical sector. This fact gave rise to the idea of the present study, which analyzed the raw data of the quality report of German hospitals with respect to this subject. Over the 9 years of report, a steady increase in the cumulative number of cases was evident, although not all body regions in which the medical laser is used followed this trend. The CO₂ laser was found to be the most commonly applied laser, even though a large spectrum of different laser types is used. Based on the present study, the importance of the laser for medical purposes can be confirmed.     

Quantum efficiencies,absolute intensities and signal‐to‐blackbody ratios of high‐temperature laser‐induced thermographic phosphors

There are a number of issues related to high‐temperature phosphor thermometry, which include measurement of faster decays, decreasing emission intensity and rising levels of blackbody radiation, that will impose limits on the maximum delectable temperature. This paper provides absolute intensity measurements, quantum efficiencies and signal‐to‐blackbody radiation ratios at peak emission wavelengths, at various temperatures (20–1400°C), for Y₂O₃:Eu, YAG:Tb and YAG:Tm thermographic phosphors under 266 and 355 nm excitation from a Q‐switched Nd:YAG laser. These terms are beneficial in a number of ways for engineers wanting to use a phosphor thermometry solution at high temperatures. They may also provide additional insight to the physical luminescence processes of phosphors at high temperatures. The phosphor signal:blackbody radiation ratio is useful because it combines the effects of blackbody radiation and phosphor emission intensities at various temperatures, providing a valuable quantitative evaluation that can be used as a design aid for phosphor selection. A figure of merit is the temperature when the blackbody radiation equals the phosphor emission (ratio = 1); this is the cross‐over temperature at which the blackbody radiation rapidly starts to overtake and mask out phosphor emissions. To the best of our knowledge no such work exists previously. The results presented show a variation in phosphor intensity with increasing temperature, and although the intensity and quantum efficiencies for Y₂O₃:Eu and YAG:Tb were much greater than YAG:Tm at low temperatures, YAG:Tm was found to be the most efficient phosphor investigated at higher temperatures (>900°C). With a peak emission wavelength of 458 nm, YAG:Tm experienced the lowest proportion of blackbody radiation therefore its advantage at higher temperatures was further amplified and was found to offer an advantage of approximately +350°C and +250°C increased upper temperature capability compared to Y₂O₃:Eu and YAG:Tb phosphors, respectively. Copyright © 2011 John Wiley & Sons, Ltd.