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Effectiveness of a fixed-depth sensor deployed from a buoy to estimate water-column cyanobacterial biomass depends on wind speed

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Journal of Environmental Sciences 2020年第7期32卷 23-29页

作者： justin d.chaffin douglas d.Kane Alex Johnson F.T Stone Laboratory and Ohio Sea Grant the Ohio State UniversityOH 43456USA division of Natural Science Applied Scienceand MathematicsDefiance CollegeDefiance OHF.T Stone LaboratoryThe Ohio State University and Ohio Sea GrantOH 43456USA

Water quality sondes have the advantage of containing multiple sensors,extended deployment times,high temporal resolution,and telecommunication with stakeholder accessible data ***,sondes that are part of buoy deployments often suffer from typically being fixed at one *** water treatment plants are interested in water quality at a depth of the water intake and other stakeholders(*** and swimmers)are interested in the surface,we examined whether a fixed depth of approximately 1 m could cause over-or under-estimation of cyanobacterial *** sampled the vertical distribution of cyanobacteria adjacent to a water quality sonde buoy in the western basin of Lake Erie during the summers of 2015–2017.A comparison of buoy cyanobacteria RFU(Relative Fluorescence Unit)at 1 m to cyanobacteria chlorophyll a(chla)measured throughout the water column showed occurrences when the buoy both under and overestimated the cyanobacteria chl a at specific *** differences between buoy measurements and at-depth grab samples occurred during low wind speeds(ds allowed cyanobacteria to accumulate at the surface above the buoy’s *** wind speeds(>4.5 m/sec)resulted in better agreement between the buoy and at-depth *** wind speeds 12 hr before sample collection decreased the difference between the buoy and at-depth samples for high wind speeds but not low *** suggest that sondes should be placed at a depth of interest for the appropriate stakeholder group or deploy sondes with the ability to sample at various depths.

关键词： Buoyancy Harmful algal bloom Lake Erie Microcystis Water quality

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Astrocytes integrate time and space

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Neural Regeneration Research 2025年第2期20卷 467-468页

作者： justin Lines department of Biological Sciences Columbia UniversityNew YorkNYUSA

Astrocytes read and react to synaptic transmission through tripartite synapses,where the binding of neurotransmitters onto astrocytic receptors triggers an increase in intracellular *** investigations have revealed that astrocytes exhibit two distinct states of intracellular calcium activity:(1)graded subcellular localized clusters with independently active microdomains,likely influenced by nearby synaptic events,and(2)whole-cell astrocyte calcium surges,believed to result from the coordinated activation of multiple ***,astrocyte calcium responses are not solely graded;instead,a spatial threshold of intracellular calcium activity can be overcome to elicit an astrocyte calcium *** these calcium responses,in turn,initiate downstream signaling pathways capable of modifying synaptic communication and overall network *** summary,astrocytes can function as integrators of local synaptic events,actively contributing to information processing within the brain.

关键词： graded integrate instead

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deciphering Water Oxidation Catalysts: The dominant Role of Surface Chemistry over Reconstruction degree in Activity Promotion

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NANO-MICRO LETTERS 2025年第1期17卷 1-15页

作者： An, Li Li, Jianyi Sun, Yuanmiao Zhu, Jiamin Seow, justin Zhu Yeow Zhang, Hong Zhang, Nan Xi, Pinxian Xu, Zhichuan J. Yan, Chun-Hua Lanzhou Univ Frontiers Sci Ctr Rare Isotopes Key Lab Nonferrous Met Chem & Resources Utilizat G State Key Lab Appl Organ ChemColl Chem & Chem Eng Lanzhou 730000 Peoples R China Nanyang Technol Univ Sch Mat Sci & Engn Singapore 639798 Singapore Chinese Acad Sci Fac Mat Sci & Energy Engn Shenzhen Inst Adv Technol Inst Technol Carbon Neutral Shenzhen 518055 Peoples R China Yunnan Univ Natl Ctr Int Res Photoelect & Energy Mat Electron Microscopy Ctr Sch Mat & EnergyKey Lab Electromagnet Mat & Devic Kunming 650091 Peoples R China Baotou Res Inst Rare Earths State Key Lab Baiyunobo Rare Earth Resource Res & Baotou 014030 Peoples R China Peking Univ Beijing Natl Lab Mol Sci State Key Lab Rare Earth Mat Chem & Applicat PKU HKU Joint Lab Rare Earth Mat & Bioinorgan Chem Beijing 100871 Peoples R China

demonstrate that the key factor to determine the activity of reconstructed surfaces is the surface chemistry, instead of reconstruction degree using the popular perovskite LaNi1-xFexO3 oxides as model *** content can influence both the surface reconstruction degree, the activation degree, and the activity of reconstructed *** oxygen evolution reaction activity of reconstructed catalysts is primarily governed by the chemistry of the reconstructed surface species. Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction. The surface reconstruction has been widely observed in perovskite catalysts, and the reconstruction degree has been often correlated with the activity enhancement. Here, a systematic study on the roles of Fe substitution in activation of perovskite LaNiO3 is reported. The substituting Fe content influences both current change tendency and surface reconstruction degree. LaNi0.9Fe0.1O3 is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi1-xFexO3 (x = 0.00, 0.10, 0.25, 0.50, 0.75, 1.00) series. The reconstructed LaNi0.9Fe0.1O3 shows a higher intrinsic activity than most reported NiFe-based catalysts. Besides, density functional theory calculations reveal that Fe substitution can lower the O 2p level, which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability. Furthermore, it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree. The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction. This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.

关键词： Oxygen evolution reaction Perovskite oxides doping Activation and reconstruction

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Inducing imperfections in germanium nanowires

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Nano Research 2017年第5期10卷 1510-1523页

作者： Subhajit Biswas Sven Barth justin d. Holmes Materials Chemistry & Analysis Group Department of Chemistry and the Tyndall National lnstitute University College Cork Cork Ireland AMBER@CRANN Trinity College Dublin Dublin 2 Ireland Vienna University of Technology Institute of Materials Chemistry Getreidemarkt 9/BCI02 1060 Vienna Austria

Nanowires with inhomogeneous heterostructures such as polytypes and periodic twin boundaries are interesting due to their potential use as components for optical, electrical, and thermophysical applications. Additionally, the incorporation of metal impurities in semiconductor nanowires could substantially alter their electronic and optical properties. In this highlight article, we review our recent progress and understanding in the deliberate induction of imperfections, in terms of both twin boundaries and additional impurities in germanium nanowires for new/enhanced functionalities. The role of catalysts and catalyst-nanowire interfaces for the growth of engineered nanowires via a three-phase paradigm is explored. Three-phase bottom-up growth is a feasible way to incorporate and engineer imperfections such as crystal defects and impurities in semiconductor nanowires via catalyst and/or interfacial manipulation. ＂Epitaxial defect transfer＂ process and catalyst-nanowire interfacial engineering are employed to induce twin defects parallel and perpendicular to the nanowire growth axis. By inducing and manipulating twin boundaries in the metal catalysts, twin formation and density are controlled in Ge nanowires. The formation of Ge polytypes is also observed in nanowires for the growth of highly dense lateral twin boundaries. Additionally, metal impurity in the form of Sn is injected and engineered via third-party metal catalysts resulting in above-equilibrium incorporation of Sn adatoms in Ge nanowires. Sn impurities are precipitated into Ge bi-layers during Ge nanowire growth, where the impurity Sn atoms become trapped with the deposition of successive layers, thus giving an extraordinary Sn content （〉6 at.%） in Ge nanowires. A larger amount of Sn impingement （〉9 at.%） is further encouraged by utilizing the eutectic solubility of Sn in Ge along with impurity trapping.

关键词： germamum nanowire vapor-liquid-solid (VLS)growth twinning impurity incorporation

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Nitrogen Constrains the Growth of Late Summer Cyanobacterial Blooms in Lake Erie

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Advances in Microbiology 2013年第6期3卷 16-26页

作者： justin d. chaffin Thomas B. Bridgeman darren L. Bade department of Environmental Sciences and Lake Erie Center University of Toledo Toledo USA

Phosphorus (P) is generally considered to be the main limiting nutrient to freshwater phytoplankton productivity. However, recent research is drawing attention to the importance of nitrogen (N) in freshwater eutrophication and N often constrains growth of cyanobacteria in small lakes. In this study we determined phytoplankton nutrient limitation in a large lake, Lake Erie during two growing seasons. during 2010 and 2011, nutrient enrichment bioassays (+P, +N and, +P and N) were conducted monthly from June through September with water collected in Maumee Bay (site MB18) and in the center of the western basin (site WBC). Nutrient concentrations were monitored every other week. At MB18, total P concentration was often >3 mmol/L and nitrate concentration decreased from >250 mmol/L in early summer to mmol/L in late summer. Nitrogen and P levels were about five-fold less at WBC. Bioassays indicated that phytoplankton nutrient limitation varied in summer, spatially, and even among phytoplankton groups. For site MB18, +P increased chlorophyll concentration in one of the eight bioassays, indicating that P did not typically limit production. For site WBC, +P increased chlorophyll concentration in six of the eight bioassays. As a result of very low ambient nitrate concentration (mmol/L) in late summer, +N (without P) increased chlorophyll concentration, suggesting symptoms of N-limitation. The N-fixing cyanobacterium Anabaena became dominant following N-limitation. This study highlights the need to reduce P loading to restore water quality. Furthermore, due to low nitrate concentration, the severity of the cyanobacterial blooms could be worse if not for N-limitation in western Lake Erie.

关键词： Cyanobacteria Eutrophication Nitrogen Phosphorus Phytoplankton

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Attribution of Fano resonant features to plasmonic particle size, lattice constant, and dielectric wavenumber in square nanoparticle lattices

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Photonics Research 2014年第1期2卷 15-23页

作者： drew deJarnette justin Norman d.Keith Roper Microelectronics and Photonics Graduate Program University of ArkansasFayettevilleArkansas 72701USA department of Chemical Engineering University of ArkansasFayettevilleArkansas 72701USA

Fano resonances between plasmons and diffracted light offer tunable energies and locales,but attribution of Fano resonance features to geometry and physicochemistry of metal nanostructures and adjacent dielectrics has been confounded by complexity and computational *** work shows predictable modal shifts of Fano resonance in square lattices of plasmonic nanostructures can be attributed directly to changes in medium wavenumber,particle size,and lattice constant that alter plasmon polarizability and diffractive *** 45 to 80 nm radius particles,a window of lattice constants that support Fano resonances is identified in a range from 500 to 900 *** constants that support high intensity resonances are determined by individual particle polarizability and medium *** resonance wavelengths redshift from diffracted photon energies as local refractive index(RI)changes due to coupling with particle polarizability in the *** sensitivities for quadrupole,dipole,and Fano resonances are 150,348,and 541 nm,respectively,per RI *** resonance intensity may be enhanced more than tenfold by selecting nanoparticle sizes and lattice *** quantitative effects of such parametric changes are rapidly and intuitively distinguished using a semi-analytic approach,consisting of an exact expression for particle polarizability,a trigonometric description of diffraction,and a semianalytical coupled dipole approximation.

关键词： lattice particle wave

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Interactive Effects of Temperature, Nitrogen, and Zooplankton on Growth and Protein and Carbohydrate Content of Cyanobacteria from Western Lake Erie

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Journal of Water Resource and Protection 2014年第12期6卷 1139-1153页

作者： deepesh Bista Scott A. Heckathorn Thomas Bridgeman justin d. chaffin Sasmita Mishra department of Environmental Sciences University of Toledo Toledo USA F.T. Stone Laboratory The Ohio State University Columbus USA

Harmful algal blooms (HABs) in freshwater ecosystems, especially of cyanobacterial species, are becoming more frequent and expanding geographically, including in Lake Erie in North America. HABs are the result of complex and synergistic environmental factors, though N or P eutrophication is a leading cause. With global mean temperatures expected to increase an additional 2°C - 5°C by 2100, cyanobacterial blooms are predicted to increase even more, given their typically-high temperature optimum for growth. We investigated how increases in temperature and nitrogen, singly or in combination, affect the growth, food quality, and herbivory of Lake Erie cyanobacteria. Algal community samples collected from Lake Erie, and isolated non-N-fixing (Microcystis aeruginosa) and N-fixing (Anabaena flos-aquae) cyanobacterial species, were cultured at 20°C, 25°C, or 30°C, and at 5, 50, 150, or 250 μM N, and then analyzed for growth and (for isolates) content of total protein and non-structural carbohydrates (NSC). Temperature and N both affected algal growth, and there were temperature × N interactions, which were sometimes affected by presence/absence of zooplankton. For example, cyanobacteria (but not green algae) growth increased with both temperature and N, especially from 25°C to 30°C, but N and herbivore presence increased cyanobacterial growth primarily only at 30°C. In general, temperature and N had little consistent effect on NSC, but increasing temperature and N tended to increase protein content in Microcystis and Anabaena (temperature effects mostly at higher N levels). In Anabaena, increases in N did not increase growth or protein at 20°C or 25°C, but did increase both at 30°C, indicating that N fixation is damaged at high temperatures and that high NO3 can overcome this damage. These results indicate that future global warming and continued eutrophication will increase cyanobacterial growth, as well influence algal herbivory and competition between N-fixing and non-N-

关键词： Cyanobacteria Great Lakes Harmful Algal Blooms Nitrogen Temperature

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Prospects for detecting ultra-high-energy particles with FAST

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Research in Astronomy and Astrophysics 2019年第2期19卷 25-38页

作者： Clancy W.James justin d.Bray Ronald d.Ekers International Centre for Radio Astronomy Research Curtin University School of Physics & Astronomy University of Manchester CSIRO Astronomy & Space Science

The origin of the highest-energy particles in nature, ultra-high-energy(UHE) cosmic rays, is still unknown. In order to resolve this mystery, very large detectors are required to probe the low flux of these particles — or to detect the as-yet unobserved flux of UHE neutrinos predicted from their interactions. The‘lunar Askaryan technique' is a method to do both. When energetic particles interact in a dense medium,the Askaryan effect produces intense coherent pulses of radiation in the MHz–GHz range. By using radio telescopes to observe the Moon and look for nanosecond pulses, the entire visible lunar surface(20 million km^2) can be used as a UHE particle detector. A large effective area over a broad bandwidth is the primary telescope requirement for lunar observations, which makes large single-aperture instruments such as the Five-hundred-meter Aperture Spherical radio Telescope(FAST) well-suited to the technique. In this contribution, we describe the lunar Askaryan technique and its unique observational requirements. Estimates of the sensitivity of FAST to both the UHE cosmic ray and neutrino flux are given, and we describe the methods by which lunar observations with FAST, particularly if equipped with a broadband phased-array feed, could detect the flux of UHE cosmic rays.

关键词： cosmic rays neutrinos techniques:miscellaneous Moon

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Long-term differences in urinary, bowel and sexual function among men treated with surgery versus radiation for prostate cancer

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Asian Journal of Andrology 2013年第4期15卷 443-444页

作者： justin d EHett James S Rosoff Sandip M Prasad department of Urology Medical University of South Carolina Charleston SC 29425 USA and Section of Urology Ralph H. Johnson VA Medical Center Charleston SC 29401 USA

surgery and radiation have both been shown to increase the longterm diseasespecific survival rate for men with din icaUy localized prostate cancer. Although both modalities have demonstrated favor able effects on cancer control, questions regarding quality of life （QoL） and func tional outcomes remain incompletely answered. To date, no randomized prospective trials have been performed comparing the two treatment modalities and so indirect compar isons of longterm functional outcomes have served as a substitute to aid in patient coun seling and decisionmaking. As there is a pau city of longterm data comparing functional outcomes after radical prostatectomy and external beam radiation therapy, a recent art icle by Resnick et al.,1 has attempted to pro vide additional information about this topic in terms of continence, erectile function and bowel function. Utilizing the Prostate Cancer Outcomes Study cohort, a populationbased cohort of men diagnosed with prostate cancer in the pro statespecific antigen （PSA） era, the authors compared rates of urinary incontinence, erect ile dysfunction, and bowel urgency at 2, 5 and 15 years after primary therapy. They showed that men undergoing prostatectomy had higher rates of incontinence and erectile dys function at 2 and 5 years, but these rates were similar to those in the radiotherapy group at 15 years. More specifically, men were approxi mately five times more likely to have urinary continence issues if they underwent prostatec tomv versus radiotherapy and almost three anda half times more likely to develop erectile dys function in the short to intermediateterm following primary treatment. As expected, rates of bowel urgency were higher in the radio therapy group at 2 and 5 years, but not sig nificantly different from the surgery group at 15 years. In addition, the authors note that the rate of incontinence and erectile function pro gressively worsened over time, regardless of primary treatment modality. At 15 years of foll

关键词： Long-term bowel sexual function

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Role of Suspended Sediments and Mixing in Reducing Photoinhibition in the Bloom-Forming Cyanobacterium Microcystis

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Journal of Water Resource and Protection 2012年第12期4卷 1029-1041页

作者： justin d. chaffin Thomas B. Bridgeman Scott A. Heckathorn Ann E. Krause Lake Erie Center and department Environmental Sciences University of Toledo Oregon USA

Toxic cyanobacterial blooms are becoming a global problem. Previous research of cyanobacterial bloom development has examined how high nutrient concentrations promote cyanobacteria dominance, and how positive buoyancy provides an ecological advantage over sinking phytoplankton. Tributaries responsible for loading nutrients into lakes often simultaneously contribute high concentrations of suspended sediments. High concentrations of suspended sediments may also influence blooms by affecting the ambient light climate, reducing photodamage, and increasing the efficiency of photosynthesis. We examined the effects of sediments and vertical mixing in potentially reducing photodamage to Microcystis by measuring photosynthetic parameters and pigment content of Microcystis in western Lake Erie during the 2008 bloom and in laboratory experiments. Photosynthetic efficiency increased with increasing sediment concentration in the lake and laboratory experiment. Content of photo-protective carotenoid pigments per dry weight decreased with increasing sediment concentrations, while the light-harvesting pigments, chl a and phycocyanin, increased with sediments. These results indicate that suspended sediments reduce photoinhibition for Microcystis. Further, photosynthetic damage was higher when Microcystis was concentrated on the surface compared to a mixed water column. Measurements of Microcystis abundance and light were also recorded, in addition to photosynthetic measurements. Greatest Microcystis abundances in Lake Erie were recorded during light-limiting conditions, which offer Microcystis both physiological and ecological benefits by reducing photoinhibition and increasing Microcystis’ advantage in light competition via buoyancy. Efforts to reduce cyanobacterial blooms may include reducing suspended sediments loads in combination with reducing nutrient loading.

关键词： Chlorophyll Fluorescence Cyanobacteria Harmful Algae Bloom Lake Erie Microcystis Suspended Sediments

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