Light Intensity Conditions Research Articles

Blue light-emitting diode photoinactivation inhibits edwardsiellosis in fancy carp (Cyprinus carpio)

Although the use of blue light (400–500nm) to reduce bacterial pathogens in fish farms has various advantages over chemical microbicides, there has been little research on applications of blue light in aquatic organism disease management. The aims of this study were to verify the bactericidal effects of light conditions (light spectrum and intensity) on Edwardsiella piscicida demonstrate the efficacy of blue light irradiation in reducing edwardsiellosis in fancy carp, and analyze the potential harmful effects of blue light on carp.E. piscicida at a concentration of 105CFUml−1 were exposed to 405 or 465nm light for an exposure time estimated to inactivate 99% of the bacteria. In vivo efficacy test of blue light emitting diodes (LEDs) was done using a cohabitation challenge in which infection rate and viable E. piscicida count in the rearing water were monitored. The potential harmful effects of the light conditions were investigated by observing histopathological changes in eye tissue, and gene expression of heat shock protein 70 and corticosteroid 11-beta-dehydrogenase isozyme 2 in kidney tissue. The percentage of E. piscicida inactivation resulting from various intensities of blue LED wavelengths demonstrated a strong correlation between light intensity and irradiation time. Furthermore, blue LED irradiation decreased the number of E. piscicida in rearing water as well as the proportion of infected fish. Histopathological examination revealed melanin granules (rod outer segment) and photoreceptors were temporarily thickened in retinas, but there were no significant differences between control and light irradiation groups after 28days of exposure. This study demonstrates that blue light irradiation is capable of inactivating E. piscicida and reducing its infection of fancy carp without causing adverse side-effects. Significance of this studyThis study provides data on photoinactivation of blue LED light on the fish pathogen Edwardsiella piscicida, and the optimal conditions of light intensity and exposure time for inactivation. We also demonstrate that appropriate blue LED exposure reduced viable E. piscicida in rearing water and infection rates without causing adverse side-effects. The use of high-intensity narrow-spectrum blue LED light, without the addition of a photosensitizer, has great potential as an eco-friendly option for treating bacterial diseases in aquatic animals, and will help to reduce the use of antibiotics.

Comparative foliar micromorphological studies of in vitro and field transferred plants of Morinda citrifolia

Micromorphological studies revealed the developmental changes in micropropagated plants of Morinda citrifolia L. from in vitro conditions to field environment. The lower relative humidity, higher light intensity and septic stressful conditions in the field environment could make gradual changes in the micropropagated plants so as to adapt the external environment. Arrested stomatal development, single guard cells and indistinct subsidiaries were observed in vitro with highest stomatal density (52.0±0.11) obtained in the ambient in vitro environment. The development of tissues, epidermal ornamentation, efficient stomatal functionality and vein-islets numbers (12.0±0.0) during in vivo transfer may help in acclimation of micropropagated plants under field conditions. Raphides were observed in the in vitro propagated as well as in vivo transferred plantlets. The gradual acclimatisation and ex vitro rooting technique increased the survival rate of plantlets in the field. The micromorphological changes resulting from in vitro to field environments are important to understand the development of tissues and adaptation of micropropagated plants, which could help in improvement in survivability during field trials.

FLUCTUATING-LIGHT-ACCLIMATION PROTEIN1, Conserved in Oxygenic Phototrophs, Regulates H+ Homeostasis and Non-Photochemical Quenching in Chloroplasts.

Plants have mechanisms allowing them to acclimate to intense light conditions, which involves the dissipation of excess light energy. These mechanisms allow plants to perform photosynthesis efficiently and, therefore, must be accurately and precisely controlled. However, how plants dissipate excess light energy has yet to be fully elucidated. Herein we report the identification of a gene, which we named Fluctuating-Light-Acclimation Protein1 (FLAP1), that is conserved in oxygenic phototrophs. We show that Arabidopsis FLAP1 is associated with chloroplast thylakoid and envelope membranes and that the flap1 mutant shows delayed non-photochemical quenching (NPQ) relaxation during induction of photosynthesis at moderate light intensity. Under fluctuating light conditions, NPQ levels in the flap1 mutant were higher than those in the wild type during the high light period, and the mutant exhibited a pale-green phenotype. These findings suggest that FLAP1 is involved in NPQ control, which is important for an acclimation response to fluctuating light.

Biological re-colonization of sub-aerial boundaries of an ‘artificial construction-niche’ contaminated by iron mine tailings: laboratory bioassays

The ability of colonizer organisms to tolerate high metal concentrations is important to the restoration and rehabilitation of mining sites. We investigated colonization on modular cellular surfaces—artificial construction-niche—prepared by combining different proportions of iron mine tailings (8% tailing dam material), soil (90%), and cement (2%) through bioassays conducted under stable laboratory conditions of humidity, temperature, and light intensity. The establishment of microorganisms was measured using CO2-respirometry and microbiological assays. Sub-aerial communities grown on the experimental materials were composed of heterotrophic and phototrophic macro- and microorganisms. Four groups of phototrophic species were observed: cyanobacteria, algae, mosses, and ferns. The cyanobacteria comprised three genera: Phormidium sp., with branched filaments, Nostoc sp. and Pseudanabaena sp.; algae included Trentepohlia sp. (Chlorophyceae), a sub-aerial or terrestrial green algae. Macroscopic fungal hyphae were also observed. CO2 production occurred in all cellular modules due to the growth of bacteria, actinobacteria, and fungi. The presence of living organisms on these artificial construction-niche containing iron ore tailings was a promising finding as those colonizers could initiate the processes of primary succession and occupy significant portions of the sub-aerial surfaces, thus actively participating in weathering and soil formation to create new ecological niches for recuperating ironstone outcrop ecosystems.

Optoelectronic Properties of Al/n-Si/ Bi4Ti3O12/Au Photosensor

We have fabricated an Al/n-Si/Bi4Ti3O12/Au photodiode by the sol-gel method. The photoelectrical response of the diode was measured under dark and various light intensity conditions. The photocurrent of the diode increases with increase in light intensity. The light sensitivity value of the photosensor was measured and observed to increase from 5.06 × 10−8 (under dark) to 2.34 × 10−4 A (under 100 mW/cm2). Furthermore, other parameters for instance, ideality factor and barrier height of the photosensors were calculated. The ideality factor and barrier height of the Al/n-Si/Bi4Ti3O12/Au photosensor were found to be 3.01 and 0.86 eV respectively. Also capacitance-voltage (C-V) characteristics were measured. The C-V graph indicates changeable behavior with the varying frequency. The value of capacitance and the interface state density Dit value decrease with increase in frequency. Thus, the obtained results indicate that the Al/n-Si/Bi4Ti3O12/Au photosensor can be used as a photosensor in optoelectronic applications.

Perancangan Sistem Telemetri Untuk Mengukur Intensitas Cahaya Berbasis Sensor Light Dependrnt Resistor Dan Arduino UNO

Light is the velocity of electromagnetic waves that spread all directions that play an important role in everyday life because it is an absolute part of life and without the light of life on earth can not develop. The amount of light illuminance is necessary to know because basically humans require adequate lighting. The instrument for measuring light illuminance is a luxmeter or light meter. However, this gauge is difficult to obtain and the price of the tool is expensive so that it can only be found in certain school laboratories or colleges. While telemetry is the process of measuring the parameters of an object (objects, space, natural conditions) that the measurement results are transmitted to other places via data transmission without or using a cable (wireless). The purpose of this study is to measure, to know the conditions of light intensity. This research uses experimental model of light intensity measurement using independent measuring instrument with combination of LDR and Arduino uno consisting of transmitter and receiver. In the transmitter there are LDR, Arduino Uno, and RF Module Board 433 MHz components, while the receiver consists of Arduino Uno, laptop, and RF Module Board 433 MHz. In this design is also done a variety of testing tools using distance variables. Overall this tool is working well. The system has successfully delivered telemetry measurement results with a range of conditions without a wall barrier with a maximum distance of <28 m. And conditions there are obstacles diding with a maximum distance <13.2.

Perancangan Sistem Telemetri Untuk Mengukur Intensitas Cahaya Berbasis Sensor Light Dependent Resistor Dan Arduino Uno

Light is a propagation of electromagnetic waves that spread all directions that play an important role in everyday life because it is an absolute part of life and without the light of life on earth can not develop. The amount of light illuminance is necessary to know because basically humans require adequate lighting. The instrument for measuring light illuminance is a luxmeter or light meter. However, this gauge is difficult to obtain and the price of the tool is expensive so that it can only be found in certain school laboratories or colleges. While telemetry is the process of measuring the parameters of an object (objects, space, natural conditions) that the measurement results are transmitted to other places via data transmission without or using a cable (wireless). The purpose of this study is to measure, to know the conditions of light intensity. This research uses experimental model of light intensity measurement using independent measuring instrument with combination of LDR and Arduino uno consisting of transmitter and receiver. In the transmitter there are LDR, Arduino Uno, and RF Module Board 433 MHz components, while the receiver consists of Arduino Uno, laptop, and RF Module Board 433 MHz. In this design is also done a variety of testing tools using distance variables. Overall this tool is working well. The system has successfully delivered telemetry measurement results with a range of conditions without a wall barrier with a maximum distance of <28 m. And conditions there are obstacles diding with a maximum distance <13.2.

Retraction: 'Each of the chloroplast potassium efflux antiporters affects photosynthesis and growth of fully developed Arabidopsis rosettes under short-day photoperiod' by Somnath Dana, Andrei Herdean, Björn Lundin and Cornelia Spetea.

Retraction: 'Each of the chloroplast potassium efflux antiporters affects photosynthesis and growth of fully developed Arabidopsis rosettes under short-day photoperiod' by Somnath Dana, Andrei Herdean, Björn Lundin and Cornelia Spetea.

Salinity Stress Alters Nutrient Uptake and Causes the Damage of Root and Leaf Anatomy in Maize

<p class="Els-Abstract-text">Salinity is one of major problems in agriculture especially in arid and semiarid area due to causes the damage of many aspects in plant growth and development. This study observed root and leaf anatomy and nutrient uptake in maize plants exposed to salinity stress. Maize seedlings were placed in the plantation room under same temperature, humidity and light intensity conditions and were treated with 0 %, 1 %, 2 % and 3 % NaCl for 5 d. Anatomy of root and leaf were observed using scanning electron microscopy (SEM). Nutrient uptake was estimated by the content of trace elements of leaves. Trace element were quantified using inductively coupled plasma-mass spectrometry (ICP-MS), but chlorine was determined by an atomic absorption flame spectrometer. The results showed that salinity slightly damaged roots anatomy. Epidermis cells and parenchyma cells of cortex and pith were shrinkage in 2 % and 3 % NaCl-treated plants. Leaf anatomy showed mesophyll and bundle sheath cells which slightly suppressed. Meanwhile, chloroplasts content inside those cells were dramatically decreased. Anatomical damage of roots and leaves was accompanied by altering uptake of some trace elements. The contents of aluminum, calcium, iron, magnesium, sodium, chlorine, in NaCl-treated plants were higher than control. Otherwise, boron, potassium and phosphor were lower in NaCl-reated plants. The rest of trace elements were in comparable concentration.</p><p> </p><p><strong>Keywords:</strong> maize; leaf; nutrient; root; salinity</p><div><p class="Els-keywords"> </p></div>

Changes in the phenolic compounds and antioxidant capacity of Berberis microphylla G. Forst. berries in relation to light intensity and fertilization

The objective of this study was to evaluate the qualitative and quantitative composition of the phenolic compounds and the antioxidant activity of B. microphylla fruit under different light intensities and levels of fertilization during two production years. Total monomeric anthocyanin concentration in high light intensity conditions was three times more than that obtained at medium light intensity, expressed for both fresh weight and dry weight terms (299.7mg/100g FFW and 9.5mg/g DFW, respectively). However, in the case of total polyphenol concentration, minor increases of 30 and 11% appeared under high light intensity in comparison with medium light intensity (906.6mg/100g FFW and 30.7mg/g DFW, respectively). Scavenging activity on DPPH was increased from 56.0 to 66.8% under the high light intensity treatment. This was also true for the reducing power which increased from 40 to 46.2%. Fertilizers reduced the flavonoid concentration, but increased the total polyphenol concentration at fertilization level 2. In the case of flavonoids, the maximum contents in fruits were 200.2 and 7.6mg (+)-catechin equivalents/100g FFW and DFW, respectively in the control treatment. The total polyphenol concentration was the highest (856.1 and 31.2mg tannic acid equivalents/g FFW and DFW, respectively) with the level fertilization 2. The scavenging activity on DPPH was from 60.3 to 62.8% when raising the fertilization level from 0 to 2, while the reducing power varied between 40.5 and 44.3% at levels 1 and 2. The total monomeric anthocyanin concentration increased with the level of fertilization in the fruits of plants at high light intensity, whereas the trend was inversed in those under medium light intensity. Hence, these studies display the possibility for maximizing both the productivity and the antioxidant capacity of fruits by crop management.

Arabidopsis thaliana FLO2 is Involved in Efficiency of Photoassimilate Translocation, Which is Associated with Leaf Growth and Aging, Yield of Seeds and Seed Quality.

FLO2, FLOURY ENDOSPERM 2, is highly conserved in higher plants, and rice FLO2 has been predicted to be involved in regulation of accumulation of storage compounds. We analyzed the function of Arabidopsis thaliana FLO2 (AtFLO2) because A. thaliana set structurally different seeds from those of rice. Although the flo2 mutant of A. thaliana showed normal germination, inflorescence and morphogenesis of flowers, peculiar phenotypes on leaves and siliques were observed, suggesting that this gene played important roles during both the vegetative and reproductive stages. The mutant leaves showed a decrease in chloroplast numbers, and increased total biomass with faster growth. When grown in high light intensity conditions, it was observed that aging events were induced. The flo2 mutant showed depressed transportation of photoassimilates into the sink organs. In the reproductive stage, the flo2 mutant had significantly smaller size siliques, causing a reduced yield of seeds. These seeds were structurally weak, and the quality of seeds was significantly lowered, with reduction of accumulation of storage compounds by seeds. A positron-emitting tracer imaging system (PETIS) analysis detected a decreased amount of photoassimilate transport in the flo2 mutant. Therefore, it was presumed that the phenotypes of the flo2 mutant were caused by reduced performance of translocation or transportation of the photoassimilates. Our observation suggests that AtFLO2 is strongly involved in regulation of translocation and transport of assimilates, and contributes greatly to quality control of the various processes involving substance supply or transfer, such as photoassimilation, leaf enlargement, yield of seeds in a silique and accumulation of seed storage compounds.

Low light illumination study on commercially available homojunction photovoltaic cells

Low illumination (10−4suns) and indoor light energy harvesting is needed to meet the demands of zero net energy (ZNE) building, Internet of Things (IoT), and beta-photovoltaic energy harvesting systems to power remote sensors. Photovoltaic (PV) solar cells under low intensity and narrow (±40nm) light spectrum conditions are not well characterized nor developed, especially for commercially available devices and scalable systems. PV operating characteristics under 1 sun illumination decrease at lower light intensity and narrow spectrum conditions (efficiency drops from ∼25% at 100mWopt/cm2 to 2% at 1μWopt/cm2). By choosing a PV with a bandgap that matches the light source operating wavelength, the total system efficiency can be improved. By quantifying losses on homojunction photovoltaics (thermalization and leakage current), we have determined the theoretical optimized efficiency for a set of PV material and a selected set of light sources. We measure single-junction solar cells’ parameters under three different light sources (indoor light and narrow spectrum LED sources) with light intensities ranging from 0.5 to 100μWopt/cm2. Measurements show that indium gallium phosphide (InGaP) PV has the highest surface power density and conversion efficiency (29% under ≈1μWopt/cm2 from a 523nm central peak LED). A beta-photovoltaic experimental study identifies InGaP to be optimized for use with the ZnS:Cu, Al and tritium at STP. The results have guided the selection of PV material for scalable isotope batteries and other low-light energy harvesting systems.

A chlorophyll fluorescence-based method for the integrated characterization of the photophysiological response to light stress.

This work introduces a new experimental method for the comprehensive description of the physiological responses to light of photosynthetic organisms. It allows the integration in a single experiment of the main established manipulative chlorophyll fluorescence-based protocols. It enables the integrated characterization of the photophysiology of samples regarding photoacclimation state (generating non-sequential light-response curves of effective PSII quantum yield, electron transport rate or non-photochemical quenching), photoprotection capacity (running light stress-recovery experiments, quantifying non-photochemical quenching components) and the operation of photoinactivation and photorepair processes (measuring rate constants of photoinactivation and repair for different light levels and the relative quantum yield of photoinactivation). The new method is based on a previously introduced technique, combining the illumination of a set of replicated samples with spatially separated actinic light beams of different intensity, and the simultaneous measurement of the fluorescence emitted by all samples using an imaging fluorometer. The main novelty described here is the independent manipulation of light intensity and duration of exposure for each sample, and the control of the cumulative light dose applied. The results demonstrate the proof of concept for the method, by comparing the responses of cultures of Chlorella vulgaris acclimated to low and high light regimes, highlighting the mapping of light stress responses over a wide range of light intensity and exposure conditions, and the rapid generation of paired light-response curves of photoinactivation and repair rate constants. This approach represents a chlorophyll fluorescence 'protocol of everything', contributing towards the high throughput characterization of the photophysiology of photosynthetic organisms.

植物工場における異なる赤青光比および光強度下で育成した赤系リーフレタスの株生産に必要な照明電力量の推定

播種後14日目に，栽植密度は12.9株m-2とした上で，赤青LEDを用いて，150，250 μmol m-2 s-1としたPPFDと0.18, 0.23としたB/R比を組み合わせた4区を設けて，赤系リーフレタスを収穫サイズまで育成し，収穫までに要する照明電力量を算定した．栽植密度12.9株 m-2では，PPFD 150 μmol m-2 s-1ではB/R比0.23区で0.18区よりも収穫までに要する照明電力量は少なかった．PPFD 250 μmol m-2 s-1ではB/R比による差はみられなかった．しかし，栽植密度を最適化した条件では，PPFD にかかわらずB/R比0.18区でB/R比0.23区よりも収穫までに要する照明電力量は少なかった．また，栽植密度12.9株m-2では，PPFD 150 μmol m-2 s-1の方が250 μmol m-2 s-1よりも収穫までに要する照明電力量は少なかったが，栽植密度を最適化した条件では，PPFD 250 μmol m-2 s-1の方が照明電力量は少なくなる傾向がみられた．本試験の範囲において，照明電力量を抑えてレタスを育成するのであれば，照明ロスがないように植物体を配置した上で，PPFDを250 μmol m-2 s-1，B/R比を0.18として育成するのがよいことが示された．本試験では，相互遮蔽の起こらない栽培条件で得られた測定値を用いて，栽植密度を最適化した場合の照明電力量を推定する手法を提示した．本解析方法は，実際の栽培現場で，試験回数を最小限に抑えて，効率的に最適な光環境条件を探索し，消費電力量を予測することができるため，実用的にも有用と考えられた．

Physiological characteristics, dry matter, and active component accumulation patterns of Changium smyrnioides in response to a light intensity gradient

Context: Changium smyrnioides Wolff (Apiaceae) is an endangered medicinal plant with numerous pharmacological uses. Objective: To investigate the effect of light intensity levels on the growth and accumulation of secondary metabolites of C. smyrnioides, cultivated seedlings were subjected to different relative light intensities via sun-shading. Materials and methods: Changium smyrnioides seedlings were subjected to five irradiance treatments (100, 60.54, 44.84, 31.39, and 10.56% sunlight) in glasshouse for 9 months. Enzymatic and non-enzymatic antioxidants with spectrophotometric method, photosynthetic parameters with Li-6400XT, dry matter accumulation and active component contents in the root with spectrophotometric and HPLC method were analyzed. Results: With an increase in relative light intensity levels, activities of enzymatic and non-enzymatic antioxidants, and malondialdehyde (MDA) contents were increased overall, while net photosynthetic rate (Pn) and dry matter accumulation patter first increased and then declined. The highest net photosynthetic rate (30.68 μmol/m2·s) and dry root weight (5.07 g) were achieved under 60.54% sunlight. Lower relative light intensity levels stimulated the accumulation levels of bioactive compounds in the roots so that the highest contents of mannitol (1.35%) and choline (405.58 μg/g) were recorded under 31.39% sunlight, and the highest polysaccharide content (10.80%) were achieved under 44.84% sunlight. With a decrease in the relative light intensity levels, the water-soluble component content increased first and then decreased. Discussion and conclusion: The results revealed that 31.39–60.54% sunlight serve as appropriate relative light intensity conditions for cultivated C. smyrnioides.

The effect of light and nutrients on algal food quality and their consequent effect on grazer growth in subtropical streams

Recent investigators have emphasized that food quality has greater importance than food quantity for herbivore somatic growth. Herbivore growth is thought to be regulated by light and nutrients through changes in food elemental ratios, but our knowledge of the mechanisms driving grazer growth in stream ecosystems is scarce. We manipulated light (through shading) and nutrients (fertilizer addition) in 3 headwater streams in southeastern Queensland, Australia, and measured the responses of natural grazer communities. The growth responses of Austrophlebioides and Helicopsyche to light and nutrients differed with their body size and periphyton food quality. Large larvae were more sensitive to increased light and nutrient availability than were small larvae. Light induced a significant negative effect on Austrophlebioides growth, and this impact increased with increasing nutrient addition. Nutrients had a pronounced positive effect on Helicopsyche growth regardless of light intensity. These responses reflected changes in food quality. Periphyton food quality in terms of C∶N played a more decisive role in grazer growth than algal food quantity (as chlorophyll a). The growth of large larvae was significantly greater under low light intensity and nutrient-enriched conditions where high-quality food was more abundant than under high-light and low-nutrient conditions where periphyton food quality was low. Our results suggest that changes in riparian vegetation or nutrient inputs can significantly influence grazer growth through changes in periphyton C∶N. We recommend that future investigators of foodweb responses to riparian canopy change or nutrient enrichment on stream ecosystems pay more attention to the effects of algal food quality rather than quantity.

Model based analysis of the growth kinetics of microalgal species residing in a waste stabilization pond

AbstractBACKGROUNDIn this study the growth kinetics of Chlorella and Scenedesmus, isolated from a Waste Stabilization Pond were investigated under different conditions of light intensity and temperature. Experimental data were collected by means of a combined respirometric and titrimetric set‐up and used to extend a mathematical model.RESULTSThe experimental results illustrated the interdependent relationship of light intensity and temperature, which had a significant influence on the microalgal growth. Consequently, a previously developed model was extended with a mathematical function that describes this relationship. The maximum specific growth rate and oxygen mass transfer coefficient were considered for model calibration. The optimized parameter values for Chlorella were μmax = 0.56 ± 0.0008 d−1 and KLa = 10.02 ± 0.02 d−1. For Scenedesmus, the optimized parameter values were μmax = 0.19 ± 0.0004 and KL a = 7.71 ± 0.004 d−1. The model with optimized parameter settings described the dissolved oxygen production (derived from the respirometric data) and the related proton consumption (derived from the titrimetric data) reasonably well for both microalgal species. The threshold value for Theil's Inequality Coefficient of 0.3 was never exceeded. In addition, model validation for both species was performed indicating good correspondence between model prediction and experimental values.CONCLUSIONSBased on the experimental observations, a previously developed mathematical model was extended with a function that describes the interaction between light intensity and temperature. After model calibration a difference in maximum specific growth rate between the two microalgal species was observed. This might be explained by differences in cell metabolism. © 2016 Society of Chemical Industry

The effects of light intensity on the growth of Japanese Gambierdiscus spp. (Dinophyceae)

Marine toxic dinoflagellates of the genus Gambierdiscus are the causative agents of ciguatera fish poisoning (CFP), a form of seafood poisoning that is widespread in tropical, subtropical and temperate regions worldwide. The distributions of Gambierdiscus australes, Gambierdiscus scabrosus and two phylotypes of Gambierdiscus spp. type 2 and type 3 have been reported for the waters surrounding the main island of Japan. To explore the bloom dynamics and the vertical distribution of these Japanese species and phylotypes of Gambierdiscus, the effects of light intensity on their growth were tested, using a photoirradiation-culture system. The relationship between the observed growth rates and light intensity conditions for the four species/phylotypes were formulated at R>0.92 (p<0.01) using regression analysis and photosynthesis-light intensity (P-L) model. Based on this equation, the optimum light intensity (Lmax) and the semi-optimum light intensity range (Ls-opt) that resulted in the maximum growth rate (μmax) and ≥80% μmax values of the four species/phylotypes, respectively, were as follows: (1) the Lmax and Ls-opt of G. australes were 208μmol photons m−2s−1 and 91–422μmol photons m−2s−1, respectively; (2) those of G. scabrosus were 252 and 120–421μmol photons m−2s−1, respectively; (3) those of Gambierdiscus sp. type 2 were 192 and 75–430μmol photons m−2s−1, respectively; and (4) those of Gambierdiscus sp. type 3 were ≥427 and 73–427μmol photons m−2s−1, respectively. All four Gambierdiscus species/phylotypes required approximately 10μmol photons m−2s−1 to maintain growth. The light intensities in coastal waters at a site in Tosa Bay were measured vertically at 1m intervals once per season. The relationships between the observed light intensity and depth were formulated using Beer’s Law. Based on these equations, the range of the attenuation coefficients at Tosa Bay site was determined to be 0.058–0.119m−1. The values 1700μmol photons m−2s−1, 500μmol photons m−2s−1, and 200μmol photons m−2s−1 were substituted into the equations to estimate the vertical profiles of light intensity at sunny midday, cloudy midday and rainy midday, respectively. Based on the regression equations coupled with the empirically determined attenuation coefficients for each of the four seasons, the ranges of the projected depths of Lmax and Ls-opt for the four Gambierdiscus species/phylotypes under sunny midday conditions, cloudy midday conditions, and rainy midday conditions were 12–38m and 12–54m, 1–16m and 1–33m, and 0m and 0–16m, respectively. These results suggest that light intensity plays an important role in the bloom dynamics and vertical distribution of Gambierdiscus species/phylotypes in Japanese coastal waters.

A mechanistic model supported by data-based classification models for batch hydrogen production with an immobilized photo-bacteria consortium

A mechanistic model for batch hydrogen production through photo-fermentation with a consortium of purple non-sulfur bacteria is proposed and developed. Kinetic parameters were obtained from experimental photo-fermentations using fluorescent lamps as artificial light source. Three different light intensities (I) were tested in order to evaluate the influence of this process variable on growth rate and hydrogen production. Optimal conditions for state variables, such as I, pH and Temperature, were experimentally obtained and then used as parameters in the mechanistic model. Kinetics from either the proposed mechanistic model or the experimental photo-fermentations were compared, obtaining similar time trajectories for the process variables when operating at optimal conditions. However, this similarity decreased slightly at different light intensities, when the pH oscillated during the fermentations. Simulations under different initial conditions of substrate concentration, pH, and light intensity were run so as to generate data sets, used for constructing data-based classification models. A complete methodology, which entails a feature extraction step with Multi-way Principal Component Analysis technique and a proper classification stage using Support Vector Machines as algorithm, was proposed and addressed in order to develop such data models. These models were validated on both simulated and experimental data, which supported the robustness not only of the data-based models but also the developed mechanistic model. One-hundred percent classification performance was obtained after validating the data-based models, which envisages a further application of these models to other fields such as process monitoring, process control or fault diagnosis.

A Third-Generation Lipid Emulsion that Contains n–3 Long-Chain PUFAs Preserves Retinal Function in Parenterally Fed Neonatal Piglets

Background: Preterm neonates and those with intestinal failure require prolonged parenteral nutrition (PN) during a critical time of early central nervous system maturation. Conventional lipid emulsions fed to preterm neonates lack n–3 (ω-3) long-chain polyunsaturated fatty acids (LC-PUFAs; >20 carbon chain in length). Recently, fish oil lipid emulsions have been developed that provide both n–6 (ω-6) and n–3 LC-PUFAs, precursors of very long–chain PUFAs (VLC-PUFAs; >24 carbon chain in length).Objective: Our objective was to determine the effect of fish oil lipid on retinal function in neonatal piglets fed total PN with the use of the lipid emulsions available in clinical practice. We hypothesized that fish oil–containing parenteral lipid would preserve retinal function more than conventional parenteral lipid.Methods: Male neonatal piglets (2–5 d of age) were fed isonitrogenous (16 g · kg−1 · d−1), isocaloric (1.1 MJ · kg−1 · d−1) PN that varied only in the lipid emulsion: Intralipid or SMOFlipid at 10 g · kg−1 · d−1 (n = 8/group). Retinal function was assessed after 14 d of treatment by recording electroretinograms under various light intensity conditions. Retinas were then harvested for histology and to determine fatty acid composition.Results: Electroretinogram intensity response curves showed greater photoreceptor a-wave amplitude in piglets fed SMOFlipid than in those fed Intralipid (percentage), for postsynaptic depolarizing bipolar cell b-waves (percentage) and for flicker electroretinogram amplitudes (percentage) (P < 0.05). Compared with those fed Intralipid, SMOFlipid-fed piglets had greater retinal total n–3 LC-PUFAs (15.7% compared with 18.4%; P = 0.04) and n–3 VLC-PUFAs (0.9% compared with 1.5%; P = 0.02), whereas Intralipid-fed piglets had greater total n–6 LC-PUFAs (13.1% compared with 10.5%; P < 0.01) and n–6 VLC-PUFAs (0.7% compared with 0.5%; P = 0.01). Histologically, retinas were indistinguishable between groups.Conclusions: In a neonatal piglet model of PN feeding, the inclusion of fish oil–based n–3 LC-PUFAs in the lipid emulsion leads to their accretion and endogenous elongation to VLC-PUFAs in the retina, which is associated with better retinal function.