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In this study, we fabricated a fiber-optic goniometer using a plastic optical fiber, a light-emitting diode, and a photodiode. The cladding of the plastic optical fiber was removed at 0.5-3mm intervals regularly to increase the bending loss of the plastic optical fiber. Also, the output voltages of the photodiode based on light intensity that measured using the fiber-optic goniometer were measured light intensities using the fiber-optic goniometer were measured to evaluate the linearity of the fiber-optic goniometer. Finally, we measured the responses of the fiber-optic goniometer for gait speeds of 3, 5, and 10 km/h using a data acquisition board and a LabVIEW program. [ABSTRACT FROM AUTHOR]

Microalgae-derived biomass has been considered as the most promising candidate for next generation biofuel due to its sustainability and biodegradability. In this study, microalgal strain Chlamydmonas reinhardtii was randomly mutagenized by using a chemical mutagen, ethyl methane sulfonate (EMS) to create mutants showing enhanced lipid production. We identified three random mutants that displayed high lipid production in the screening using Nile red staining. Among those, mutant #128 was selected as candidate for further studies. Our flow cytometry and confocal microscopy analysis revealed that mutant #128 contains larger and more abundant lipid bodies than that of wild-type. Moreover, mutant #128 showed 1.4-fold increased fatty acid methyl ester (FAME) content compared to wild-type under nitrogen depleted condition. In addition, mutant #128 grew faster and accumulated more biomass, resulting in high lipid production. 2D gel electrophoresis and MALDI-TOF analysis used for gene targeting revealed that β-subunit of mitochondrial ATP Synthase and two-component response regulator PilR may be involved in enhanced characteristics of mutant #128. These results show the possibilities of EMS mediated random mutagenesis in generation of mutants to produce high amount of lipid as well as further study for molecular mechanism of mutants. [ABSTRACT FROM AUTHOR]

Ability to increase the lipid production in microalgae is one of the heavily sought-after ideas to improve the economic feasibility of microalgae-derived transportation fuels for commercial applications. We used the oxidative stress by TiO nanoparticles, a well-known photocatalyst, to induce lipid production in microalgae. Chlorella vulgaris UTEX 265 was cultivated under various concentrations of TiO ranging from 0.1 to 5 g/L under UV-A illumination. Maximum specific growth rate was affected in responding to TiO concentrations. In the presence of UV-A, chlorophyll concentration was decreased at the highest concentration of TiO (5 g/L TiO) by oxidative stress. The fatty acid ethyl ester (FAME) composition analysis suggested that oxidative stress causes the accumulation and decomposition of lipids. The highest FAME productivity was 18.2 g/L/d under low concentrations of TiO (0.1 g/L) and a short induction time (two days). The controlled condition of TiO/UV-A inducing oxidative stress (0.1 g/L TiO and two days induction) could be used to increase the lipid productivity of C. vulgaris UTEX 265. Our results show the possibility of modulating the lipid induction process through oxidative stress with TiO/UV-A. [ABSTRACT FROM AUTHOR]

Optical fibers can be a medium to produce Cerenkov light due to their dielectric components, and radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, we measured and characterized gamma-ray induced Cerenkov light in silica optical fibers, a plastic optical fiber, and a plastic wavelength shifting fiber in order to select the adequate optical fiber for producing Cerenkov light. Also, we measured the intensity of Cerenkov light as functions of irradiated length, irradiation angle, and thickness of various scatterers using the chosen optical fiber. [ABSTRACT FROM PUBLISHER]

In this study, a fiber-optic dosimeter (FOD) was developed to measure entrance surface dose (ESD) in diagnostic radiology. We measured the scintillating lights in order to obtain ESDs, which changed with the various exposure parameters of a digital radiography (DR) system, such as tube potential, current-time product, focus-surface distance (FSD), and field size, using the fabricated FOD system. From the experimental results, the output light signals of the FOD were similar to the ESDs of the conventional semiconductor dosimeter. In conclusion, we characterized the measured ESDs as functions of exposure parameters by using two different types of dosimeters and demonstrated that the proposed FOD using a plastic scintillating fiber and a plastic optical fiber (POF) makes it possible to measure ESDs in the energy range of diagnostic radiology. From the results of this study, it is anticipated that the FOD will be a useful dosimeter in low-energy photon applications including diagnostic radiology. [ABSTRACT FROM AUTHOR]

We developed a scintillating fiber-optic image sensor system (SFISS) using square plastic optical fibers (POFs), a scintillating film, a right-angle mirror, and a complementary metal-oxide semiconductor (CMOS) image camera for dosimetry in radiotherapeutic applications. In this study, the scintillating light images were obtained for measuring two-dimensional planar dose distributions of a 6MV photon beam in a solid-water phantom. We also measured the percentage depth doses (PDDs) of 6 and 15MV photon beams using the SFISS and compared them with those obtained using conventional dosimetry films. The proposed sensor has many advantages, such as real-time readout, high-resolution measurement, and lack of corrections for temperature, pressure, and humidity. From the results of this study, it is expected that a SFISS can be developed to accurately measure the dose distribution in a small beam field for stereotactic radiosurgery (SRS). [ABSTRACT FROM AUTHOR]

A fiber-optic radiation sensor (FORS), which is composed of an inorganic scintillator, a plastic optical fiber (POF), a photomultiplier tube (PMT), and a multichannel analyzer (MCA), was developed for gamma-ray energy spectroscopy. In this study, we selected a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) as the sensitive element of the FORS and found that LYSO:Ce with dimensions of 3 × 3 × 15mm gives the best performance in obtaining a gammaray energy spectrum. The FORS allows us to measure the energy spectra of Co-60, Na-22, and Cs-137. [ABSTRACT FROM AUTHOR]

In this study, we developed a fiber-optic pH sensor based on a sol-gel film immobilized with neutral red (NR). A solgel film was prepared by mixing tetramethylorthosilicate (TMOS), trimethoxymethylsilane (MTMS), ethanol (EtOH), distilled water (HO), and NR powder. Accordingly, the thin pH sol-gel film was fabricated through a sol-gel process with a dip-coating method. The thickness and diameter of the fabricated pH sol-gel film are 0.11 and 0.6 mm, respectively. We measured the optical absorbance and the light intensity with the spectra of reflected light, which change with the color variation of the pH sol-gel film in the fiber-optic sensing probe. From the experimental results, we demonstrated that the proposed fiber-optic pH sensor has good reversibility, reproducibility, and a fast response time, in which the optical properties of the NR-based pH sol-gel film change with the pH value. [ABSTRACT FROM AUTHOR]

The purpose of this study is to develop a more convenient system for measurement of hand rotation, and to validate the system by correlation of performance indices derived from the system with the bradykinesia score of hand rotation movement during on-medication state. Forty patients with Parkinson's disease and 14 age-matched control subjects participated in this study. The measurement system was developed using a ceramic gyroscope that is significantly smaller and lighter than those in the literature. The sensor signal was bandpass filtered and action tremor was eliminated by additional lowpass filtering (fc=5Hz) with automated tremor discrimination. Four performance indices (RMS velocity and RMS angle, peak power and total power) were derived from the angular velocity signal. Correlations of performance indices with clinical scores and difference of performance indices among subject groups were investigated. Correlations of all performance indices were far better with bradykinesia score of hand rotation (best r=−.78) than with the other categorized subscores of UPDRS (bradykinesia subscore, axial symptom subscore, and total motor score; best r=−.64). Elimination of action tremor resulted in improvement in correlations of RMS velocity and total power with bradykinesia score for hand rotation (r=−.84 from −.81). Differences between low scores were greater in total power and differences between high scores were greater in RMS velocity, suggesting that use of more than one PI would be beneficial for diagnosis of a wide range of patients. The convenient sensor system, action tremor elimination, and performance indices suggested in this study are expected to be useful in clinical situations. [ABSTRACT FROM AUTHOR]

In this study, we developed a remote gamma-ray spectroscopy system based on a fiber-optic radiation sensor (FORS) that is composed of an inorganic scintillator coated with reduced graphene oxide (RGO) and a plastic optical fiber (POF). As a preliminary experiment, we measured the transmitted light intensities using RGO membranes of different thicknesses with different wavelengths of emitted light. To evaluate the FORS performance, we determined the optimal thickness of the RGO membrane and measured the amounts of scintillating light and gamma energy spectra using radioactive isotopes such as 60Co and 137Cs. The amounts of scintillating light from the RGO-coated inorganic scintillators increased, and the energy resolutions of the gamma-ray spectra were enhanced. In addition, the gamma-ray energy spectra were measured using different types of RGO-coated inorganic scintillators depending on the lengths of the POFs for remote gamma-ray spectroscopy. It was expected that inorganic scintillators coated with RGO in FORS can deliver improved performance, such as increments of scintillating light and energy resolution in gamma-ray spectroscopy, and they can be used to identify nuclides remotely in various nuclear facilities. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the effect of 30% oxygen inhalation on visuospatial cognitive performance, blood oxygen saturation, and heart rate. Six male (25.8(mean)±1.0(SD) years) and six female (23.8±1.9 years) college students participated in this experiment. Two psychological tests were developed to measure the performance level of visuospatial cognition. The experiment consisted of two runs: one was a visuospatial cognition task under normal air (21% oxygen) condition and the other under hyperoxic air (30% oxygen) condition. The experimental sequence in each run consisted of four phases, that were Rest1 (1min), Control (1min), Task (4min), and Rest2 (4min). Blood oxygen saturation and heart rate were measured throughout the course of four phases. The analysis of behavioral performance with 30% oxygen administration when compared to 21% oxygen revealed that the mean performance was improved. When supplied 30% oxygen in the air, the blood oxygen saturation was increased while the heart rate was decreased compared to those under 21% oxygen condition. We conclude that 30% oxygen inhalation enhanced visuospatial performance by the increased the oxygen saturation in the blood. [Copyright &y& Elsevier]

Abstract: In this study, a miniature fiber-optic radiation detector has been developed using a water-equivalent organic scintillator for electron beam therapy dosimetry. Usually, two kinds of light signals such as fluorescent and Cherenkov lights are generated in a fiber-optic radiation detector when a high-energy electron beam is irradiated. The fluorescent light signal is produced in the scintillator and is transmitted through a plastic optical fiber to a remote light-measuring device such as a PMT or a photodiode. The Cherenkov light could be also produced in the plastic optical fiber itself and be detected by a light-measuring device. Therefore, it could cause problems or limit the accuracy of the detection of a fluorescent light signal that is proportional to dose. The objectives of this study are to measure, characterize and eliminate Cherenkov light generated in a plastic optical fiber used as a component of a fiber-optic radiation detector and to detect a real fluorescent light signal from the scintillator. In this study, the intensity of Cherenkov light is measured and characterized as a function of the incident angle of an electron beam from a LINAC, as a function of the electron beam energy, and as a function of electron beam size. Also, a subtraction method using a background optical fiber without a scintillator and an optical discrimination method using optical filters are investigated to remove Cherenkov light. [Copyright &y& Elsevier]

This study investigated the effects of 30% oxygen administration on visuospatial cognitive ability using time course data analysis of fMRI. A visuospatial task was presented while brain images were scanned by a 3T MRI system. The results showed that there was an improvement in performance and also increased BOLD intensity in the parietal lobe in the higher oxygen condition. There was positive relation between behavior performance and BOLD intensity in the right parietal lobe. This result supports the conclusion that the increase in the cognitive processing ability due to highly concentrated oxygen can be explained by the increase in the BOLD intensity. [ABSTRACT FROM AUTHOR]

Although algal biofuels have been promoted as a carbon-neutral alternative to fossil fuels, several economic and technological barriers challenge the much-anticipated success of algae as a commercial bio-feedstock. In particular, utilizing only a lipid portion of harvested algal biomass limits possible monetary returns from algal biomass within which non-lipid compounds generally comprise a major proportion. Previous studies thus demonstrated the production of ethanol from defatted algal biomass to improve overall economic outlook of the nascent algae industry; however, it is also possible to utilize residual algal biomass as a fermentation substrate for bacterial strains producing high value alternative products. Therefore, the goal of this study was to compare the yield of biosurfactant from B. subtilis C9 in conventional culture medium and the acid hydrolysate of defatted Chlorella biomass (DCB). Although increasing the concentration of acid catalyst from 0 N to 1.0 N was expected to proportionally enhance the effectiveness of dilute acid hydrolysis, the results indicated that DCB hydrolysates treated under different acid conditions at 121 °C for 15 min exhibited the highest yield of fermentable monosaccharides when treated with 0.25 N HCl. Subsequently, the fermentation of B. subtilis C9 was performed in both Luria-Bertani (LB) and DCB hydrolysate medium after adjusting salinity and monosaccharide concentration to identical levels; a significantly greater yield of biosurfactant was observed in the culture grown with DCB hydrolysate medium, while the presence of magnesium and manganese co-factors in DCB hydrolysate contributed to a greater biosurfactant yield. Collectively, these results suggest that the valorization of defatted algal biomass could be also accomplished by incorporating biosurfactant fermentation into algal biorefinery processes and call for further process optimization efforts that consider factors associated with the operation of industrial algal biorefineries. • For the first time, defatted algal biomass was used for biosurfactant production. • 48% (w/w) of defatted Chlorella was acid hydrolyzed into fermentable monosaccharides. • High yield of biosurfactant was achieved without nutrients supplementation. • Presence of metal co-factors facilitated a high yield of bacterial biosurfactant. • Metals can be effectively supplemented from upstream algal biomass processing. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper. [ABSTRACT FROM AUTHOR]

Attached cultivation systems have been receiving extensive attention as a breakthrough in microalgae cultivation technology. However, there is a lack of studies that emphasize precise optimization of important parameters in attached cultivation of microalgae. In this study, the effects of two major environmental parameters in photoautotrophic cultivation, light intensity and CO2 concentration, on the biomass and lipid surface productivity of Ettlia sp. YC001 were optimized by employing Response Surface Methodology (RSM) and validated experimentally. The optimum initial conditions for attached cultivation were use of seed from the late exponential phase (LE) and an inoculum surface density of 2.5 g/m2. By optimization, maximum biomass surface productivity of 28.0 ± 1.5 g/m2/day was achieved at 730 μE/m2/s with 8% CO2. The maximum lipid surface productivity was 4.2 ± 0.3 g/m2/day at 500 μE/m2/s with 7% CO2. Change of the fatty acid composition with respect to changes in environment parameters led to improvement of biodiesel quality at higher light intensity and higher CO2 concentration. Attached cultivation of Ettlia sp. YC001 has successfully produced biomass and lipids at a high production rate with relatively low light energy demand and high CO2 utilization. [ABSTRACT FROM AUTHOR]

Microalgae have great potential for the production of biofuels due to the ability of the organism to accumulate large quantities of storage lipids under stress conditions. Mitogen activated protein kinase (MAPK) signaling cascades are widely recognized for their role in stress response signal transduction in eukaryotes. To assess the correlation between MAPK activation and lipid productivity, Chlamydomonas reinhardtii was studied under various concentrations of NaCl. The results demonstrated that C. reinhardtii exhibits elevated levels of extracellular-signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) activities after undergoing osmotic stress, as well as an increase in cellular lipid content. To establish a more direct causal link between both kinases and lipid productivity, C. reinhardtii was subjected to biochemically induced regulation of ERK and JNK pathways. Activating the MEK-ERK pathway via C6 ceramide treatment increased ERK activation and lipid production simultaneously, while PD98059 mediated inhibition of the pathway yielded opposite results. Interestingly, suppression of the JNK pathway with SP600125 resulted in a substantial decrease in cell viability under osmotic stress. These results suggest that ERK and JNK MAP kinases have important roles in microalgal lipid accumulation and cell growth under osmotic stress, respectively. [ABSTRACT FROM AUTHOR]

Background: Microalgae, being a phototroph, grow in the presence of light, and utilizing photons in narrow and specific range of wavelengths. There have been numerous attempts to take advantage of this trait of wavelength-dependent growth for the purpose of increasing biomass productivity. One potential option involves wavelength conversion of sunlight. In the present study, three fluorescent dyes with blue, red, and green emission spectra were employed with the aim of improving sunlight utilization efficiency and thus enhancing biomass and lipid productivity of Nannochloropsis gaditana. Results: When DPA and R101 were used to enrich blue and red spectra, biomass productivity of Nannochloropsis gaditana was increased by 35.1 and 40.3%, respectively. The maximum quantum yield values were higher than 0.6 at the early stage of growth for the cultures grown under DPA- and R101-modified solar radiation. Chlorophyll a content was also 57.0 and 32.3% higher than the control at the early growth stage under DPA- and R101-modified solar radiation, respectively. This stimulation of photosynthetic activity at the early growth stage correlated well with rapid growth under DPA- and R101-modified light during the first 4 days of cultivation. Lipid productivity consequently increased by 26.9 (DPA) and 39.4% (R101) after 10 days of cultivation. An immediate effect on lipid induction was observed in cultures under modified light, which exhibited 19.1% improvement in lipid content at the cost of some degree of impaired growth. Conclusion: Fluorescent dyes with the capability of enriching wavelengths of light favored by the algal photosystem could indeed be an effective means of promoting growth of Nannochloropsis gaditana. This strategy would be particularly powerful for mass cultivation where sunlight is the only economically viable option for illumination. [ABSTRACT FROM AUTHOR]

Background: Intracortical brain-machine interfaces (BMIs) harness movement information by sensing neuronal activities using chronic microelectrode implants to restore lost functions to patients with paralysis. However, neuronal signals often vary over time, even within a day, forcing one to rebuild a BMI every time they operate it. The term "rebuild" means overall procedures for operating a BMI, such as decoder selection, decoder training, and decoder testing. It gives rise to a practical issue of what decoder should be built for a given neuronal ensemble. This study aims to address it by exploring how decoders' performance varies with the neuronal properties. To extensively explore a range of neuronal properties, we conduct a simulation study.Methods: Focusing on movement direction, we examine several basic neuronal properties, including the signal-to-noise ratio of neurons, the proportion of well-tuned neurons, the uniformity of their preferred directions (PDs), and the non-stationarity of PDs. We investigate the performance of three popular BMI decoders: Kalman filter, optimal linear estimator, and population vector algorithm.Results: Our simulation results showed that decoding performance of all the decoders was affected more by the proportion of well-tuned neurons that their uniformity.Conclusions: Our study suggests a simulated scenario of how to choose a decoder for intracortical BMIs in various neuronal conditions. [ABSTRACT FROM AUTHOR]

The heterotrophic cultivation of microalgae has a number of notable advantages, which include allowing high culture density levels as well as enabling the production of biomass in consistent and predictable quantities. In this study, the full potential of Chlorella sp. HS2 is explored through optimization of the parameters for its heterotrophic cultivation. First, carbon and nitrogen sources were screened in PhotobioBox. Initial screening using the Plackett-Burman design (PBD) was then adopted and the concentrations of the major nutrients (glucose, sodium nitrate, and dipotassium phosphate) were optimized via response surface methodology (RSM) with a central composite design (CCD). Upon validation of the model via flask-scale cultivation, the optimized BG11 medium was found to result in a three-fold improvement in biomass amounts, from 5.85 to 18.13 g/L, in comparison to a non-optimized BG11 medium containing 72 g/L glucose. Scaling up the cultivation to a 5-L fermenter resulted in a greatly improved biomass concentration of 35.3 g/L owing to more efficient oxygenation of the culture. In addition, phosphorus feeding fermentation was employed in an effort to address early depletion of phosphate, and a maximum biomass concentration of 42.95 g/L was achieved, with biomass productivity of 5.37 g/L/D. [ABSTRACT FROM AUTHOR]

This study sets out to harvest microalgae through auto-flocculation by manipulating the interactive effect of calcium, phosphate, and polysaccharides (PSAs). The harvesting efficiency (H.E) of 91 ± 2.7% was achieved for Ettlia sp. through auto-flocculation. The H.E was attributed to the chelation of calcium and PSAs present in microalgae medium. In the absence of PSAs, the H.E reduced to 64 ± 05% only. The addition of phosphate (34 ± 0.13 mg L−1) increased the H.E to 73 ± 1.5%. Zeta-potential measurements showed that the harvesting was induced by charge neutralization and inter-particle bridging. The PSAs-based auto-flocculation was tested for Chlorella sp. too but it turned out the H.E of 51 ± 1.3% only. The flocculation did not take place when the co-harvesting of Ettlia sp. and Chlorella sp. was carried out. It is concluded that each microalgae specie shows different auto-flocculation mechanism due to variation in their PSAs characteristics. It triggers up the need for setting up a distinct protocol for different microalgae species to assess their auto-flocculation potential. Image 1 • Ettlia sp. showed the harvesting efficiency (H.E) of 91% through auto-flocculation. • The interaction of calcium and polysaccharides (PSAs) prompted auto-flocculation. • The provision of excess phosphate decreased the H.E. • The presence of PSAs facilitated Ettlia sp. auto-flocculation but inhibited Chlorella sp. auto-flocculation. [ABSTRACT FROM AUTHOR]

The optimum concentration of dissolved carbon in the microalgal culture medium is a vital requirement for enhanced biomass production. The present study investigates the effect of supplying NaHCO 3 with CO 2 as the inorganic carbon source to enhance the utilization efficiency of CO 2 for maximum FAME productivity of Chlorella sp. HS2. The specific growth rate (0.615 d −1 ), biomass productivity (530.1 mg L −1  d −1 ), CO 2 biofixation rate (996.4 mg L −1 d −1 ), FAME productivity (141.8 mg L −1 d −1 ) and FAME content (26.76%) were found to be maximized at NaHCO 3 concentration of 0.5 g L −1 with 1% (v/v) CO 2 enriched air (0.25 vvm flow rate) supplementation in shake flask condition. The FAME productivity (169.37 mg L −1 d −1 ) and FAME content (31.2%) were 1.19 and 1.16 times higher respectively in the flat panel photobioreactor than in shake flask condition. Fatty acid profile and biofuel properties show suitability for biodiesel production. The economic assessment revealed that combining supplementation of both carbon sources greatly reduces the carbon supply costs, from $8.92 Kg −1 when only NaHCO 3 was used as the carbon source down to $0.86 Kg −1 when 1% CO 2 was supplied alongside NaHCO 3 . These findings show that combined application of NaHCO 3 and CO 2 is the more cost-effective approach of supplying carbon source to microalgae for FAME production. [ABSTRACT FROM AUTHOR]

Background: Microalgae's low tolerance to high CO2 concentrations presents a significant challenge for its industrial application, especially when considering the utilization of industrial exhaust gas streams with high CO2 content—an economically and environmentally attractive option. Therefore, the objectives of this study were to investigate the metabolic changes in carbon fixation and lipid accumulation of microalgae under ambient air and high CO2 conditions, deepen our understanding of the molecular mechanisms driving these processes, and identify potential target genes for metabolic engineering in microalgae. To accomplish these goals, we conducted a transcriptomic analysis of the high CO2-tolerant strain, Chlorella sp. ABC-001, under two different carbon dioxide levels (ambient air and 10% CO2) and at various growth phases. Results: Cells cultivated with 10% CO2 exhibited significantly better growth and lipid accumulation rates, achieving up to 2.5-fold higher cell density and twice the lipid content by day 7. To understand the relationship between CO2 concentrations and phenotypes, transcriptomic analysis was conducted across different CO2 conditions and growth phases. According to the analysis of differentially expressed genes and gene ontology, Chlorella sp. ABC-001 exhibited the development of chloroplast organelles during the early exponential phase under high CO2 conditions, resulting in improved CO2 fixation and enhanced photosynthesis. Cobalamin-independent methionine synthase expression was also significantly elevated during the early growth stage, likely contributing to the methionine supply required for various metabolic activities and active proliferation. Conversely, the cells showed sustained repression of carbonic anhydrase and ferredoxin hydrogenase, involved in the carbon concentrating mechanism, throughout the cultivation period under high CO2 conditions. This study also delved into the transcriptomic profiles in the Calvin cycle, nitrogen reductase, and lipid synthesis. Particularly, Chlorella sp. ABC-001 showed high expression levels of genes involved in lipid synthesis, such as glycerol-3-phosphate dehydrogenase and phospholipid-diacylglycerol acyltransferase. These findings suggest potential targets for metabolic engineering aimed at enhancing lipid production in microalgae. Conclusions: We expect that our findings will help understand the carbon concentrating mechanism, photosynthesis, nitrogen assimilation, and lipid accumulation metabolisms of green algae according to CO2 concentrations. This study also provides insights into systems metabolic engineering of microalgae for improved performance in the future. [ABSTRACT FROM AUTHOR]

Radiation from gamma-ray emitting radionuclides poses significant health risks due to its high penetrating power. Currently, no technique offers effective shielding against it. Nevertheless, the rapid increase in the production and application of radionuclides warrants efficient and reliable radionuclide-detection systems. Although conventional scintillation detectors that adopt spectral analysis are widely used for their cost-effectiveness and robustness, their performance can be hindered by factors such as radioactive statistical fluctuations and background radiation. Advanced spectral-processing techniques, including machine-learning approaches, offer improvements; however, they are generally computationally intensive and not suitable for rapid onsite applications. In this study, a novel analytical approach for radionuclide identification based on the ratio of scintillation light output from scintillators with different attenuation properties is proposed. The scintillator assembly comprises four cylindrical scintillators: bismuth germanate (BGO), cerium-doped gadolinium gallium garnet (GAGG:Ce), europium-doped calcium fluoride (CaF 2 :Eu), and polyvinyltoluene-based plastic scintillators. The deposited energy in each scintillator is simulated using the Monte Carlo N-Particle Transport (MCNP) code, and the amount of scintillation light output (SLO) is calculated by a mathematical light yield model of the scintillator. From the calculated light output, the light output ratios for different scintillator combinations are derived and their dependence on the energy of incident gamma rays is evaluated. This approach exploits a parameter called equivalent energy to estimate the gamma-ray energy, which is then used to identify gamma ray-emitting radionuclides by comparing the results with known intensity-weighted average energies. The proposed method is validated with both monoenergetic and polyenergetic gamma rays using standard gamma-ray data. The results demonstrate that SLO ratio-based approach can effectively identify radionuclides without relying on traditional spectral measurement techniques, offering a promising alternative for rapid and efficient gamma-ray detection and analysis. • In MCNP simulation, we identify monoenergetic/polyenergetic gamma-ray radionuclides using scintillators. • Scintillators with various characteristics provide diverse radionuclide features. • Scintillation light output ratios allow identification in specific energy levels. • The proposed approach is simple and practical for radionuclide identification. [ABSTRACT FROM AUTHOR]

Microalgae-derived docosahexaenoic acid (DHA) production has been considered an alternative technology to overcome several disadvantages of fish oil-based DHA production. Despite its potential, efficient production methods for DHA have been rarely reported. Accordingly, in this study we investigated the potential application of Jerusalem artichoke and lipid-extracted algae (LEA) hydrolysates as inexpensive sources of carbon and other nutrients for DHA production using Aurantiochytrium sp. KRS101. Response surface methodology (RSM) with central composite design (CCD) was used to determine the maximum point of DHA productivity in the presence of 51.9 g L−1 fructose and 4.9 g L−1 yeast extract. Hydrolysis of 76.6 g L−1 Jerusalem artichoke powder with 0.25 N sulfuric acid at 70 °C yielded the desired concentration of fructose for use as the medium. Cultivation of the microalgae using the Jerusalem artichoke hydrolysate (JAH) and JAH + LEA (JLH-1) resulted in 27.8% and 31.3% improvements in biomass productivity, respectively, compared with the basal medium control. In addition, simultaneous one-step hydrolysis of Jerusalem artichoke and LEA (JLH-2) resulted in 7.2% higher biomass and 47% higher DHA yields than that obtained from hydrolyzing the two components separately (JLH-1). These results suggested that a strategy using JAH combined with LEA could replace expensive nutrient sources and produce efficient and eco-friendly DHA from Aurantiochytrium sp. KRS101. [ABSTRACT FROM AUTHOR]

• MCNP6.1 demonstrates suitability of JENDL/HE-2007 and LAHET150 over 20 MeV neutrons. Reaction rate analyses of high-energy neutrons and 100 MeV protons are conducted experimentally by combining the Monte Carlo codes and the nuclear data libraries, in the proton beam transport facility at the Kyoto University Critical Assembly. For the number of neutrons per proton, the ratio of high-energy neutrons for threshold energy under 20 MeV and 100 MeV protons is successfully reconstructed by combining JENDL-4.0 and the INCL model of the PHITS3.0 code with a relative difference about 10% between the experiments and the calculations. The MCNP6.1 code significantly demonstrates with the suitability of combining JENDL/HE-2007 (for high-energy neutrons) and LAHET150 (for protons) for analyzing the 209Bi(n , xn)210-x Bi reaction rates of the high-energy neutrons over 20 MeV. In further studies, reaction rate analyses of neutrons over 20 MeV, such as 209Bi(n , 7 n)203Bi reactions, still remain to be improved by combining the Monte Carlo code and nuclear data libraries. [ABSTRACT FROM AUTHOR]

• The keyword extraction A.I. model is pre-trained by an unsupervised learning using document data, and transfer-learned by a supervised learning. • The room extraction A.I. model is framework based on the deep neural network for detection about drawing data. • The statistical test is automatically conducted and shown its conclusion of whether or not the release criteria are satisfied. • The data management module can control the entire process of RSSI evaluation for the long-term project. The site characterization should be conducted during the entire decommissioning period to verify the compliance with regulatory guidance and to demonstrate the safety for site release. A technical manual called Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) has been widely used as a reference for the site characterization. Historically, it has required enormous resources because of extensive data handling. And there is a possibility of a human error because of the expert's judgement reliance. In this study, software called COde for Site characterization and Management of Overall Surveys (COSMOS) has been developed with Artificial Intelligence (AI) models. One of the AI model is possible to revolutionary reduce time for finding keyword related contamination, and the other manages database by digitalizing drawings. Also, other survey modules are possible to conduct related all of statistical tests. In the end, COSMOS would be utilized as a total management solution for site characterization. [ABSTRACT FROM AUTHOR]

In this study, a fiber-optic remote temperature sensor (FRTS) for real-time temperature measurements in a spent nuclear fuel pool is developed. The proposed FRTS consists of a fiber-optic temperature-sensing probe and an optical time-domain reflectometer (OTDR). The probe of an FRTS consists of silicone oil, a fiber channel (FC) terminator, a single-mode optical fiber, and a copper metal cap. Silicone oil is employed as a temperature-sensing material owing to its temperature-dependent refractive index. The optical powers of the reflected light signals (Fresnel reflection), which are generated at the interface between the silicone oil and the core of a single-mode optical fiber in the distal end of the sensing probe, are measured. The temperature of the water was measured in 5 ℃ increments ranging from 10 to 70 ℃, using a fabricated FRTS and an OTDR. The proposed FRTS could be used to effectively monitor the water temperature of a spent nuclear fuel pool (SNFP) at a nuclear power plant (NPP). [ABSTRACT FROM AUTHOR]

• Co-cultivation of two microalgae species (Ettlia and Chlorella) was tested. • Co-cultivation returned the maximum biomass productivity at 1:08 inoculation ratio. • Biomass productivity in mono-culture was 0.26 g L−1 day−1. • Biomass productivity in co-cultivation was 0.70 g L−1 day−1. • Co-cultivation was more effective in mixotrophic condition than autotrophic. This study aimed to investigate the symbiotic relationship of two freshwater microalgae species, Ettlia sp. and Chlorella sp. HS-2 to improve biomass productivity. The species were co-cultivated autotrophically under the inoculation ratios (Chlorella / Ettlia) of 1:01, 1:04, 1:08, and 1:16. The performance of co-cultivation was compared with monoculture. It found that the co-cultivation returned higher biomass productivity (P < 0.05) than the monoculture under all inoculation ratios. The highest biomass productivity of 0.70 ± 0.02 g L−1 day−1 was achieved with an inoculation ratio of 1:08. The biomass productivity further increased to 0.74 ± 0.06 g L−1 day−1 by switching the cultivation mode to the mixotrophic condition. The biomass productivity of mixotrophic co-cultivation was higher P < 0.05 (0.74 ± 0.06 g L−1 day−1) than the mixotrophic mono-culture of Ettlia (0.41 ± 0.06 g L−1 day−1) but equal to mixotrophic mono-culture of Chlorella. FACS analysis revealed that the biomass obtained after co-cultivation contained 81% of Chlorella cells. In biochemical composition, co-cultivation (autotrophic) biomass contained protein 41%, carbohydrates 33%, lipids 11%, and pigments 2% of dry cell weight. The major fatty acids produced in the co-cultivation were C16–C18, which are favorable for biodiesel production. It is concluded that the co-cultivation is more favorable than the monoculture to obtain high biomass productivity and stable biomass composition. [ABSTRACT FROM AUTHOR]

While the screening and development of robust algal crops have mostly focused on determining strains that exhibit the highest possible yields of biomass or desirable biomolecules, these criteria do not necessarily lead to finding algal strains with high tolerance to varying outdoor cultivation conditions. Herein, we report Chlorella sp. HS2 isolated from a tidal rock pool nearby a local coastal waterfall that presumably experienced fluctuations in salinity, pH, and temperature. Compared to two reference strains, Chlorella sp. HS2 exhibited relatively high tolerance to a wide range of salinity (0–5% (w/v) of supplemental NaCl), pH (3.0–10.5), and temperature (14–46 °C) with substantially high biomass accumulation. While the supplementation of either gaseous CO2 or sodium bicarbonate enhanced algal growth, the mixotrophic and heterotrophic cultivations of Chlorella sp. HS2 further indicated its propensity to grow favorably under the presence of organic carbon sources. Subsequent PBR cultivation of Chlorella sp. HS2 under optimal light and/or temperature conditions suggested the highest specific growth rate during mixotrophy, while the analyses of the harvested biomass identified palmitate, oleate, and linoleate as major fatty acid methyl esters, and lutein and ß-carotene as predominant carotenoids. Substantially, high growth rates of Chlorella sp. HS2 under a wide range of abiotic conditions and different trophic modes with favorable biochemical composition thus strongly support our algal isolate as a robust and reliable algal crop that can be deployed to achieve high production of commercially important biomolecules and to incorporate simultaneous treatment of wastewater or CO2-replete flue gas into algal cultivation. [ABSTRACT FROM AUTHOR]

In this study, we developed a scintillating fiber phantom dosimeter (SFPD) that can measure the transverse and longitudinal dose distributions of a Co-60 teletherapy source. The SFPD system is composed of organic scintillating fibers, polymethyl methacrylate (PMMA) phantoms, and a complementary metal–oxide–semiconductor (CMOS) sensor camera. When the phantom dosimeter is irradiated with gamma rays from a Co-60 teletherapy source, scintillating lights are emitted from the scintillating fibers inserted in the phantom dosimeter. The scintillating images are measured using a CMOS camera in real time and analyzed using an image processing program. The proposed phantom dosimeter has many advantages such as real-time measurement, easy calibration, and immunity to electromagnetic interference. In addition, it can measure complex dose distributions more precisely, because it has a high spatial resolution due to the small size of organic scintillating fibers. To evaluate the performance of the proposed phantom dosimeter, transverse and longitudinal dose distributions are measured using the CMOS sensor camera. Dose distributions are measured according to the field sizes and compared to the results obtained using an EBT3 film and MCNPX calculations. [ABSTRACT FROM AUTHOR]

The light greatly affects the physiological properties of microalgae, but the outcome is species-specific. To improve the traits of microalgae suitable for biofuel production, we investigated the influence of the light on biomass and lipid productivity of Chlorella sp. HS2. Photosynthetic performance in terms of relative electron transport rate (rel. ETR) was maximized at 450 μmol photons m−2 s−1, which allowed cells to reach high biomass productivity of 1.10 g L−1 day−1. Although the stress was induced by excessive irradiance under 750 μmol photons m−2 s−1, Chlorella sp. HS2 was able to maintain a high growth rate and achieved higher biomass productivity (1.34 g L−1 day−1) compared to that of other Chlorella species. In an effort to understand the relationship between photosynthesis and biomass productivity, we found out that effective quantum yield [Y(II)] and rel. ETR of Chlorella sp. HS2 is relatively higher than that of Chlorella vulgaris. The total lipid content decreased as the light intensity increased at the exponential phase. Interestingly, however, this trend was reversed during the stationary phase. This implies that the high light may synergistically induce lipids when the cells undergo nutrient starvation. The lipid content and productivity continued to increase up to 0.25 g L−1 day−1 even after the light saturation point. The fraction of esterifiable lipid suitable for biodiesel production rapidly increased from 50% to 99% during the stationary phase. These results suggest that species-specific high light based cultivation can be an effective strategy to improve the lipid productivity in Chlorella sp. HS2. • Light control affected biomass and lipid productivity of Chlorella sp. HS2. • Photosynthetic efficiency was maximized at 450 μmol photons m−2 s−1. • Biomass productivity reached 1.34 g L−1 day−1 under 700 μmol photons m−2 s−1. • Lipid productivity increased along with light intensity at stationary phase. • Esterifiable lipid fraction increased up to 99% with high light control. [ABSTRACT FROM AUTHOR]

Abstract Flocculation is an effective technique for harvesting microalgae due to low energy input and being scalable up to industrial algaculture. In this study, four different flocculants at various concentration, and pH levels were employed for the harvesting of Chlorella sp. HS2. Among the tested flocculants, chitosan showed the highest flocculation efficiency of 99.6% ± 0.25 at 10 mg L−1 dosage, pH 8.0 and 30 min of sedimentation. It turned out that the choice of flocculants had minimum impact on the fatty acids methyl ester (FAME) yield and composition. When the reusability of the spent medium for each flocculant was investigated, the culture supernatant obtained from chitosan-based harvesting method had lower growth inhibitory effects in comparison to those harvested using the other flocculants. The cost analysis also favored chitosan-based flocculation, because it returned the highest flocculant efficiency while the flocculant dosage was the lowest. Due to its high harvest efficiency and low impact on the water footprint, it was concluded that the chitosan offer promising advantages over other flocculants. Graphical abstract Image 103955 Highlights • Flocculation of Chlorella sp. HS2 with various cationic flocculants was evaluated. • Flocculation efficiency can enhanced by modulation of medium pH. • Highest flocculation efficiency of 99.6% was achieved using chitosan at pH 8. • Reusability of the medium is dependent on the type of flocculant that is used. [ABSTRACT FROM AUTHOR]

Development of transgenic strains of microalgae is necessary to obtain microalgal strains that are capable of producing high levels of oils and a variety of bio-products. However, microalgae have a much lower transformation efficiency in comparison to other micro-organisms due to the presence of thick cell walls. Here, a two-pronged approach for optimizing the electroporation parameters combined with the application of secondary metabolites from myxobacteria to weaken the cell wall was used to maximize the transformation efficiency of Nannochloropsis salina (Eustigmatophyceae). When the electroporation parameters were set at 50 pulses of square waves at a field strength of 12,000 V cm−1, a transformation efficiency of up to 53 per 108 cells was achieved for N. salina in the early exponential phase of growth. Next, cultivation of the microalgae using bacterial conditioned F2N medium containing 10% supernatant of the myxobacteria strain DZ2 resulted in a moderate inhibition of the growth rate and distinctive morphological changes. Flow cytometry confirmed an increase in the overall cell size as well as granularity. When the bacterial medium conditioned cells were employed for transformation under optimized electroporation conditions, the transformation efficiency improved 2.71-fold up to 144 per 108 cells. Taken together, a combinatory approach for electroporation using high field strength square wave pulses and conditioning cells with myxobacterial supernatant is a promising method for the efficient genetic transformation of microalgae. [ABSTRACT FROM AUTHOR]

Even though there has been much interest in genetic engineering of microalgae, its progress has been slow due to the difficulty and limitation of available techniques. Currently, genetic modification in most microalgal strains is confined to single gene transformation. Here, a multigene expression system for the oleaginous model strain Nannochloropsis salina was developed with glycine-serine-glycine spacer linked 2A self-cleaving peptides (2A) for the first time. An efficiency test of the four most widely used 2As revealed that two different types of 2As T2A and E2A have the best performance in N. salina with a maximum cleavage rate of nearly 45%. The system was able to express the linked sequence of the selection marker sh ble and the fluorescence protein sfCherry with intact functions. Because 2A enabled multigene expression in the single cassette form, the use of 2A also reduced the vector size, which along with the stronger promoter resulted in a 9-fold increase in the transformation efficiency. Furthermore, confirmative screening accuracy of more than 90% was observed. Hence, the 2A applied vector system is expected to be beneficial in microalgal research field because it enables multigene expression as well as offering improved transformation and screening efficiency. [ABSTRACT FROM AUTHOR]