bluuebunny/crossref_metadata_2025 huggingface dataset:
Viewing Angle Dependent Transmittance Spectra of One-Dimensional Photonic Crystals
Authors: Huang Yuan Ming , Zhai Bao Gai , Cai Yun Gao
Published: November 2010

Characteristic matrix method was used to calculate the transmittance spectra of the one-dimensional photonic crystals (1-D PCs). By theoretical calculations, the transmittance spectra of time-harmonic electromagnetic wave in the 1-D PCs with various incident angles were derived. From the transmittance spectra, it shown that along with the incident angle increased from 0o to 85o, the frequency range of stop band gap also increased from 0.085 to 0.119 for the certain periodicity N=16 of the 1-D PCs. In addition, for a certain incident angle (in this letter, the incident angle 30o was used), the transmittance spectra for different periodicity (N=2, 4, 8 and 16 respectively) were also calculated, it demonstrated that different incident angles could influence the stop band gap range markedly, but on the transmittance was minimal.
Synthesis and Photovoltaic Properties of Oligothiophene Derivatives with Liquid Crystal Properties
Authors: Guan Li , Wang Juan , La Ming , Zhong Yi Ping , Liu Ping , Deng Wen Ji
Published: November 2010

For the purpose of developing novel photovoltaic materials and organic photovoltaic devices with good performance characteristics, 5-cyano-2,2′:5′,2″-terthiophene (3T-CN) and 5-cyano -2,2′:5′,2″:5″,2″′-tetrathiophene (4T-CN) were synthesized. The 3T-CN and 4T-CN was donor-acceeptor type oligothiophene derivatives with liquid crystal properties. The rigid and flexible photovoltaic devices were fabricated using 3T-CN, 4T-CN and 3,4,9,10-perylenetertracarboxylic dianhydride (PTCDA). Comparision of the rigid device based on 4T showed that both rigid device glass-ITO/4T-CN/PTCDA/Al and flexible device PET-ITO/4T-CN/PTCDA/Al had higher short circuit current density (Isc) and power conversion efficiency (PCE) than that of glass-ITO/4T /PTCDA/Al. The -CN group played an important role in increasing Isc and PCE. It is due to that the mesogenic properties of 4T-CN, which enhances the efficiency by promoting forward interfacial electron transfer.
Improved Stability of Unsealed Quasi-Solid-State Dye-Sensitized Solar Cell Using Poly(3,4-Ethylenedioxythiophene) Film as Layer Electrolyte
Authors: Vivekaphirat Suthida , Saekung Chaiyuth , Thang San H. , Wongchaisuwat Atchana , Arunchaiya Marisa
Published: November 2010

Quasi-solid/solid polymer electrolytes have been the subject of extensive research for an alternative of liquid electrolyte for dye-sensitized solar cells (DSSCs) because of their advantages such as alleviated leakage, lower environmental impact and ease of device fabrication. In this work, the performance of the unsealed quasi-solid-state DSSCs based on composite poly (ethylene oxide) (PEO) electrolyte and N719 dye-sensitizer was examined on aging under atmospheric condition. The energy conversion efficiency of DSSC using the composite PEO electrolyte was 5.62 % under sun simulated light, AM 1.5 (100 mW cm-2) but gradually decreased to 0.95 % on aging for 90 days. An additional layer of poly(3,4-ethylenedioxythiophene) (PEDOT) electrolyte was incorporated with the composite polymer electrolyte for DSSC fabrication. The PEDOT layer was prepared by electrochemical polymerization of bis-ethylenedioxythiophene (bis-EDOT) and characterized by Raman spectroscopy and cyclic voltammetry. It was found that the energy conversion efficiency of DSSC based on the composite polymer electrolyte incorporated with PEDOT layer was 5.57 % and gradually decreased to 1.76 % under the same aging condition. Thus an additional layer of PEDOT electrolyte provided an improved stability of DSSC.
Preparation of Ag2S Thin Films by Electro-Deposition
Authors: Guo Xing Yu , Cheng Shu Ying , Lu Pei Min , Zhou Hai Fang
Published: November 2010

Ag2S thin films were fabricated on the ITO-coated glass substrates by cathodically electro-deposition from the mixture solution including 0.01mol·L-1 AgNO3 and 0.05 mol·L-1 Na2S2O3 with pH=2.5 at room temperature. The microstructure and surface morphology of the films were investigated with the deposition potential (E) varied from -0.23V to -0.28V. The X-ray diffractograms show that the deposited films are monoclinic Ag2S with the relative deviation of cell parameters within 1.5%. The estimated cell parameters of the Ag2S films deposited at E = -0.25V are closest to those of the standard sample. The SEM pictures show that films are uniform with better compactness at more negative deposition potential, but there are some aggregation when the potential up to -0.28V. According to the AFM images, the root mean square (RMS) roughness and grain size decrease with the decreasing of potential absolute value, but they will increase when the deposition potential is too small. The best potential is -0.25V for depositing Ag2S thin films.
Synthesis of High-Performance Aqueous CdSe Quantum Dots Based on Combination of Se Source as Vapor-Phase and Hydrothermal Method
Authors: Qiu Heng Kang , Shen Yue , Wang Lin Jun , Zhang Jian Cheng , Qin Kai Feng
Published: November 2010

High performance aqueous CdSe quantum dots (QDs) have been prepared by combination of Se source as vapor-phase and hydrothermal method. The main advantages of this approach included: one is to utilize H2Se vapor as a higher pure selenium source to make the prepared QDs have little other impurities, another is to obtain the QDs with characteristics of more rapid growth in the hydrothermal reaction. The as-prepared products have been characterized by ultraviolet-visible absorption spectra, photoluminescence spectroscopy (PL), X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive spectroscopy (EDS) analysis etc. The results show the as-synthesized water-soluble CdSe nanoparticles possess higher purity and quantum yields (QY), favorable narrow photoluminescence band with full width of half-maximum (FWHM) down to 40 nm, better photo-stability, and less synthetic time as compared with aqueous CdSe QDs obtained by other methods.
M2b Monocytes Predominated in Peripheral Blood of Severely Burned Patients
Authors: Kobayashi Makiko , Jeschke Marc G. , Shigematsu Kenji , Asai Akira , Yoshida Shohei , Herndon David N. , Suzuki Fujio
Published: November 2010

Severely burned patients were shown to be carriers of M2 monocytes, and all of the monocytes isolated from peripheral blood of severely burned patients (19 of 19 patients) were demonstrated as M2b monocytes (IL-12−IL-10+CCL1+ monocytes). Low levels of M2a (IL-12−IL-10+CCL17+ monocytes) and M2c monocytes (IL-12−IL-10+CXCL13+ monocytes) were demonstrated in peripheral blood of severely burned patients (M2a, 2 of 19 patients; M2c, 5 of 19 patients). M2b, M2a, and M2c monocytes were not detected in peripheral blood of healthy donors. However, M2b monocytes appeared when healthy donor monocytes were cultured in media supplemented with burn patient serum (15%). CCL2 was detected in sera of all burn patients, and M2b monocytes were not generated from healthy donor monocytes cultured with media containing 15% burn patient sera that were previously treated with anti-CCL2 mAb. In addition, M2b monocytes were generated from healthy donor monocytes in cultures supplemented with rCCL2. These results indicate that M2b monocytes are predominant in peripheral blood of severely burned patients who are carriers of CCL2 that functions to stimulate monocyte conversion from resident monocytes to M2b monocytes.
Human Eosinophils Exert TNF-α and Granzyme A-Mediated Tumoricidal Activity toward Colon Carcinoma Cells
Authors: Legrand Fanny , Driss Virginie , Delbeke Marie , Loiseau Sylvie , Hermann Emmanuel , Dombrowicz David , Capron Monique
Published: November 2010

Peripheral blood and tissue eosinophilia is a prominent feature in allergic diseases and helminth infections. In cancer patients, tumor-associated tissue eosinophilia is frequently observed. Tumor-associated tissue eosinophilia can be associated with a favorable prognosis, notably in colorectal carcinoma. However, underlying mechanisms of eosinophil contribution to antitumor responses are poorly understood. We have in this study investigated the direct interactions of human eosinophils with Colo-205, a colorectal carcinoma cell line, and show that eosinophils induce apoptosis and directly kill tumor cells. Using blocking Abs, we found that CD11a/CD18 complex is involved in the tumoricidal activity. Coculture of eosinophils with Colo-205 led to the release of eosinophil cationic protein and eosinophil-derived neurotoxin as well as TNF-α secretion. Moreover, eosinophils expressed granzyme A, which was released upon interaction with Colo-205, whereas cytotoxicity was partially inhibited by FUT-175, an inhibitor of trypsin-like enzymatic activity. Our data present the first demonstration, to our knowledge, that granzyme A is a cytotoxic mediator of the eosinophil protein arsenal, exerting eosinophil tumoricidal activity toward Colo-205, and provide mechanistic evidence for innate responses of eosinophil against tumor cells.
Pim-1 Regulates RANKL-Induced Osteoclastogenesis via NF-κB Activation and NFATc1 Induction
Authors: Kim Kabsun , Kim Jung Ha , Youn Bang Ung , Jin Hye Mi , Kim Nacksung
Published: November 2010

Pim kinases are emerging as important mediators of cytokine signaling pathways in hematopoietic cells. In this study, we demonstrate that Pim-1 positively regulates RANKL-induced osteoclastogenesis and that Pim-1 expression can be upregulated by RANKL signaling during osteoclast differentiation. The silencing of Pim-1 by RNA interference or overexpression of a dominant negative form of Pim-1 (Pim-1 DN) in bone marrow-derived macrophage cells attenuates RANKL-induced osteoclast formation. Overexpression of Pim-1 DN blocks RANKL-induced activation of TGF-β–activated kinase 1 (TAK1) and NF-κB as well as expression of NFATc1 during osteoclastogenesis. However, we found that overexpression of TAK1 in the presence of Pim-1 DN rescues NF-κB activation. Additionally, Pim-1 interacts with RANK as well as TAK1, indicating that Pim-1 is involved in RANKL-induced NF-κB activation via TAK1. Furthermore, we demonstrate that Pim-1 also regulates NFATc1 transcription activity and subsequently induces osteoclast-associated receptor expression, an osteoclast-specific gene. Taken together, our results reveal that Pim-1 positively regulates RANKL-induced osteoclastogenesis.
Oligodendrocyte-Specific FADD Deletion Protects Mice from Autoimmune-Mediated Demyelination
Authors: Mc Guire Conor , Volckaert Thomas , Wolke Uta , Sze Mozes , de Rycke Riet , Waisman Ari , Prinz Marco , Beyaert Rudi , Pasparakis Manolis , van Loo Geert
Published: November 2010

Apoptosis of oligodendrocytes (ODCs), the myelin-producing glial cells in the CNS, plays a central role in demyelinating diseases such as multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. To investigate the mechanism behind ODC apoptosis in EAE, we made use of conditional knockout mice lacking the adaptor protein FADD specifically in ODCs (FADDODC-KO). FADD mediates apoptosis by coupling death receptors with downstream caspase activation. In line with this, ODCs from FADDODC-KO mice were completely resistant to death receptor-induced apoptosis in vitro. In the EAE model, FADDODC-KO mice followed an ameliorated clinical disease course in comparison with control littermates. Lymphocyte and macrophage infiltration into the spinal cord parenchyma was significantly reduced, as was the extent of demyelination and proinflammatory gene expression. Collectively, our data show that FADD is critical for ODC apoptosis and the development of autoimmune demyelinating disease.
TLR5 as an Anti-Inflammatory Target and Modifier Gene in Cystic Fibrosis
Authors: Blohmke Christoph J. , Park Julie , Hirschfeld Aaron F. , Victor Rachel E. , Schneiderman Julia , Stefanowicz Dorota , Chilvers Mark A. , Durie Peter R. , Corey Mary , Zielenski Julian , Dorfman Ruslan , Sandford Andrew J. , Daley Denise , Turvey Stuart E.
Published: November 2010

New treatments are needed to improve the health of people with cystic fibrosis (CF). Reducing lung-damaging inflammation is likely to be beneficial, but specific anti-inflammatory targets have not been identified. By combining cellular immunology with a population-based genetic modifier study, we examined TLR5 as an anti-inflammatory target and modifier gene in CF. Using two pairs of human CF and control airway epithelial cells, we demonstrated that the TLR5–flagellin interaction is a major mediator of inflammation following exposure to Pseudomonas aeruginosa. To validate TLR5 as an anti-inflammatory target, we analyzed the disease modifying effects of the TLR5 c.1174C>T single nucleotide polymorphism (rs5744168) in a large cohort of CF patients (n = 2219). rs5744168 encodes a premature stop codon and the T allele is associated with a 45.5–76.3% reduction in flagellin responsiveness (p < 0.0001). To test the hypothesis that reduced TLR5 responsiveness would be associated with improved health in CF patients, we examined the relationship between rs5744168 and two clinical phenotypes: lung function and body weight. Adults with CF carrying the TLR5 premature stop codon (CT or TT genotype) had a higher body mass index than did CF patients homozygous for the fully functional allele (CC genotype) (p = 0.044); however, similar improvements in lung function associated with the T allele were not statistically significant. Although follow-up studies are needed to confirm the impact of TLR5 on nutritional status, this translational research provides evidence that genetic variation in TLR5 resulting in reduced flagellin responsiveness is associated with improved health indicators in adults with CF.
MicroRNA-148/152 Impair Innate Response and Antigen Presentation of TLR-Triggered Dendritic Cells by Targeting CaMKIIα
Authors: Liu Xingguang , Zhan Zhenzhen , Xu Li , Ma Feng , Li Dong , Guo Zhenhong , Li Nan , Cao Xuetao
Published: November 2010

MicroRNAs (miRNAs) are involved in the regulation of immunity, including the lymphocyte development and differentiation, and inflammatory cytokine production. Dendritic cells (DCs) play important roles in linking innate and adaptive immune responses. However, few miRNAs have been found to regulate the innate response and APC function of DCs to date. Calcium/calmodulin-dependent protein kinase II (CaMKII), a major downstream effector of calcium (Ca2+), has been shown to be an important regulator of the maturation and function of DCs. Our previous study showed that CaMKIIα could promote TLR-triggered production of proinflammatory cytokines and type I IFN. Inspired by the observations that dicer mutant Drosophila display defect in endogenous miRNA generation and higher CaMKII expression, we wondered whether miRNAs can regulate the innate response and APC function of DCs by targeting CaMKIIα. By predicting with software and confirming with functional experiments, we demonstrate that three members of the miRNA (miR)-148 family, miR-148a, miR-148b, and miR-152, are negative regulators of the innate response and Ag-presenting capacity of DCs. miR-148/152 expression was upregulated, whereas CaMKIIα expression was downregulated in DCs on maturation and activation induced by TLR3, TLR4, and TLR9 agonists. We showed that miR-148/152 in turn inhibited the production of cytokines including IL-12, IL-6, TNF-α, and IFN-β upregulation of MHC class II expression and DC-initiated Ag-specific T cell proliferation by targeting CaMKIIα. Therefore, miRNA-148/152 can act as fine-tuner in regulating the innate response and Ag-presenting capacity of DCs, which may contribute to the immune homeostasis and immune regulation.
CD30 Ligand Is a Target for a Novel Biological Therapy against Colitis Associated with Th17 Responses
Authors: Sun Xun , Yamada Hisakata , Shibata Kensuke , Muta Hiromi , Tani Kenzaburo , Podack Eckhard R. , Iwakura Yoichiro , Yoshikai Yasunobu
Published: November 2010

We have previously found that CD30 ligand (CD30L; CD153)/CD30 signaling executed by the T–T cell interaction plays a critical role in Th17 cell differentiation, at least partly via downregulation of IL-2 production. In this study, we investigated the role of CD30L in the development of colitis experimentally induced by dextran sulfate sodium (DSS), in which IL-17A is involved in the pathogenesis. CD30L−/− mice were resistant to both acute colitis induced by administration of 3 to ∼5% DSS and to chronic colitis induced by administration of 1.5% DSS on days 0–5, 10–15, and 20–25 as assessed by weight loss, survival rate, and histopathology. The levels of IFN-γ, IL-17A, and IL-10 were significantly lower but the IL-2 level higher in the lamina propria T lymphocytes of CD30L−/− mice than those in lamina propria T lymphocytes of wild-type mice after DSS administration. Soluble murine CD30-Ig fusion protein, which was capable of inhibiting Th17 cell differentiation in vitro, ameliorated both types of DSS-induced colitis in wild-type mice. Modulation of CD30L/CD30 signaling by soluble CD30 could be a novel biological therapy for inflammatory diseases associated with Th17 responses.
FcR-Like 2 Inhibition of B Cell Receptor-Mediated Activation of B Cells
Authors: Jackson Tanisha A. , Haga Christopher L. , Ehrhardt Götz R. A. , Davis Randall S. , Cooper Max D.
Published: November 2010

FcR-like (FCRL) 2 is a transmembrane protein with immunomodulatory potential that is preferentially expressed by memory B cells in humans. It has two consensus ITIMs in addition to a putative ITAM sequence in its cytoplasmic domain. We have confirmed the cellular distribution of FCRL2 and analyzed its functional potential to show that coligation with the BCR leads to tyrosine phosphorylation of its ITIM motifs and subsequent Src homology region 2 domain-containing phosphatase-1 recruitment to facilitate inhibition of BCR signaling. Mutational analysis indicates that the tyrosine residues in both inhibitory motifs of FCRL2 are required for complete inhibition of BCR signaling, whereas tyrosines in the putative activation motif are dispensable for signal modulation. These findings suggest a negative immunomodulatory function for FCRL2 in the regulation of memory B cells.
Basophils Support the Survival of Plasma Cells in Mice
Authors: Gomez Manuel Rodriguez , Talke Yvonne , Goebel Nicole , Hermann Fabian , Reich Barbara , Mack Matthias
Published: November 2010

We have previously shown that basophils support humoral memory immune responses by increasing B cell proliferation and Ig production as well as inducing a Th2 and B helper phenotype in T cells. Based on the high frequency of basophils in spleen and bone marrow, in this study we investigated whether basophils also support plasma cell survival and Ig production. In the absence of basophils, plasma cells of naive or immunized mice rapidly undergo apoptosis in vitro and produce only low amounts of Igs. In contrast, in the presence of basophils and even more in the presence of activated basophils, the survival of plasma cells is markedly increased and continuous production of Igs enabled. This effect is partially dependent on IL-4 and IL-6 released from basophils. Similar results were obtained when total bone marrow cells or bone marrow cells depleted of basophils were cultured in the presence or absence of substances activating basophils. When basophils were depleted in vivo 6 mo after immunization with an Ag, specific Ig production in subsequent bone marrow cultures was significantly reduced. In addition, depletion of basophils for 18 d in naive mice significantly reduced the number of plasma cells in the spleen. These data indicate that basophils are important for survival of plasma cells in vitro and in vivo.
MicroRNAs and Multiple Sclerosis
Authors: Tufekci Kemal Ugur , Oner Meryem Gulfem , Genc Sermin , Genc Kursad
Published: November 2010

MicroRNAs (miRNAs) have recently emerged as a new class of modulators of gene expression. miRNAs control protein synthesis by targeting mRNAs for translational repression or degradation at the posttranscriptional level. These noncoding RNAs are endogenous, single-stranded molecules approximately 22 nucleotides in length and have roles in multiple facets of immunity, from regulation of development of key cellular players to activation and function in immune responses. Recent studies have shown that dysregulation of miRNAs involved in immune responses leads to autoimmunity. Multiple sclerosis (MS) serves as an example of a chronic and organ-specific autoimmune disease in which miRNAs modulate immune responses in the peripheral immune compartment and the neuroinflammatory process in the brain. For MS, miRNAs have the potential to serve as modifying drugs. In this review, we summarize current knowledge of miRNA biogenesis and mode of action and the diverse roles of miRNAs in modulating the immune and inflammatory responses. We also review the role of miRNAs in autoimmunity, focusing on emerging data regarding miRNA expression patterns in MS. Finally, we discuss the potential of miRNAs as a disease marker and a novel therapeutic target in MS. Better understanding of the role of miRNAs in MS will improve our knowledge of the pathogenesis of this disease.
Peroxy radical partitioning during the AMMA radical intercomparison exercise
Authors: Andrés-Hernández M. D. , Stone D. , Brookes D. M. , Commane R. , Reeves C. E. , Huntrieser H. , Heard D. E. , Monks P. S. , Burrows J. P. , Schlager H. , Kartal D. , Evans M. J. , Floquet C. F. A. , Ingham T. , Methven J. , Parker A. E.
Published: November 2010

Abstract. Peroxy radicals were measured onboard two scientific aircrafts during the AMMA (African Monsoon Multidisciplinary Analysis) campaign in summer 2006. This paper reports results from the flight on 16 August 2006 during which measurements of HO2 by laser induced fluorescence spectroscopy at low pressure (LIF-FAGE) and total peroxy radicals (RO2* = HO2+ΣRO2, R = organic chain) by two similar instruments based on the peroxy radical chemical amplification (PeRCA) technique were subject of a blind intercomparison. The German DLR-Falcon and the British FAAM-BAe-146 flew wing tip to wing tip for about 30 min making concurrent measurements on 2 horizontal level runs at 697 and 485 hPa over the same geographical area in Burkina Faso. A full set of supporting measurements comprising photolysis frequencies, and relevant trace gases like CO, NO, NO2, NOy, O3 and a wider range of VOCs were collected simultaneously. Results are discussed on the basis of the characteristics and limitations of the different instruments used. Generally, no data bias are identified and the RO2* data available agree quite reasonably within the instrumental errors. The [RO2*]/[HO2] ratios, which vary between 1:1 and 3:1, as well as the peroxy radical variability, concur with variations in photolysis rates and in other potential radical precursors. Model results provide additional information about dominant radical formation and loss processes.
Diurnally resolved particulate and VOC measurements at a rural site: indication of significant biogenic secondary organic aerosol formation
Authors: Sjostedt S. J. , Slowik J. G. , Brook J. R. , Chang R.Y.-W. , Mihele C. , Stroud C. A. , Vlasenko A. , Abbatt J. P. D.
Published: November 2010

Abstract. We report simultaneous measurements of volatile organic compound (VOC) mixing ratios including C6 to C8 aromatics, isoprene, monoterpenes, acetone and organic aerosol mass loadings at a rural location in Southwestern Ontario, Canada by Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) and Aerosol Mass Spectrometry (AMS), respectively. During the three-week-long Border Air Quality and Meteorology Study in June–July 2007, air was sampled from a range of sources, including aged air from the polluted US Midwest, direct outflow from Detroit 50 km away, and clean air with higher biogenic input. After normalization to the diurnal profile of CO, a long-lived tracer, diurnal analyses show clear photochemical loss of reactive aromatics and production of oxygenated VOCs and secondary organic aerosol (SOA) during the daytime. Biogenic VOC mixing ratios increase during the daytime in accord with their light- and temperature-dependent sources. Long-lived species, such as hydrocarbon-like organic aerosol and benzene show little to no photochemical reactivity on this timescale. From the normalized diurnal profiles of VOCs, an estimate of OH concentrations during the daytime, measured O3 concentrations, and laboratory SOA yields, we calculate integrated organic aerosol production amounts associated with each measured SOA precursor. Depending on whether the SOA formation is occurring in a low- or high-NOx regime, we estimate that the biogenic gases contribute between 10 to 36 times as much SOA as do the aromatic precursors, making this a highly biogenically dominated region for SOA formation. The conclusion that biogenic SOA formation is of significance to air quality in this region is supported by detailed air quality modeling during this period (Stroud et al., 2010).
Characteristics, sources, and transport of aerosols measured in spring 2008 during the aerosol, radiation, and cloud processes affecting Arctic climate (ARCPAC) project
Authors: Brock C. A. , Cozic J. , Bahreini R. , Froyd K. D. , Middlebrook A. M. , McComiskey A. , Brioude J. , Cooper O. R. , Stohl A. , Aikin K. C. , de Gouw J. A. , Fahey D. W. , Ferrare R. A. , Gao R.-S. , Gore W. , Holloway J. S. , Hübler G. , Jefferson A. , Lack D. A. , Lance S. , Moore R. H. , Murphy D. M. , Nenes A. , Novelli P. C. , Nowak J. B. , Ogren J. A. , Peischl J. , Pierce R. B. , Pilewskie P. , Quinn P. K. , Ryerson T. B. , Schmidt K. S. , Schwarz J. P. , Sodemann H. , Spackman J. R. , Stark H. , Thomson D. S. , Thornberry T. , Veres P. , Watts L. A. , Warneke C. , Wollny A. G.
Published: November 2010

Abstract. We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project of April 2008. We then summarize airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea-ice inversion layer to 7.4 km altitude. Second, a region of depleted (relative to the background) aerosol was present within the surface inversion layer over sea-ice. Third, layers of dense, organic-rich smoke from open biomass fires in Southern Russia and Southeastern Siberia were frequently encountered at all altitudes from the top of the inversion layer to 7.1 km. Finally, some aerosol layers were dominated by components originating from fossil fuel combustion. Of these four categories measured during ARCPAC, the diffuse background aerosol was most similar to the average springtime aerosol properties observed at a long-term monitoring site at Barrow, Alaska. The biomass burning (BB) and fossil fuel layers were present above the sea-ice inversion layer and did not reach the sea-ice surface during the course of the ARCPAC measurements. The BB aerosol layers were highly scattering and were moderately hygroscopic. On average, the layers produced a noontime net heating of ~0.1 K day−1 between 2 and 7 km and a~slight cooling at the surface. The ratios of particle mass to carbon monoxide (CO) in the BB plumes, which had been transported over distances >5000 km, were comparable to the high end of literature values derived from previous measurements in fresh wildfire smoke. These ratios suggest minimal precipitation scavenging and removal of the BB particles between the time they were emitted and the time they were observed in dense layers above the sea-ice inversion layer.
Long-term analysis of carbon dioxide and methane column-averaged mole fractions retrieved from SCIAMACHY
Authors: Schneising O. , Buchwitz M. , Reuter M. , Heymann J. , Bovensmann H. , Burrows J. P.
Published: November 2010

Abstract. Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases contributing to global climate change. SCIAMACHY onboard ENVISAT (launch 2002) was the first and is now together with TANSO onboard GOSAT (launch 2009) the only satellite instrument currently in space whose measurements are sensitive to CO2 and CH4 concentration changes in the lowest atmospheric layers where the variability due to sources and sinks is largest. We present long-term SCIAMACHY retrievals (2003–2009) of column-averaged mole fractions of both gases (denoted XCO2 and XCH4) derived from absorption bands in the near-infrared/shortwave-infrared (NIR/SWIR) spectral region focusing on large-scale features. The results are obtained using an upgraded version (v2) of the retrieval algorithm WFM-DOAS including several improvements, while simultaneously maintaining its high processing speed. The retrieved mole fractions are compared to global model simulations (CarbonTracker XCO2 and TM5 XCH4) being optimised by assimilating highly accurate surface measurements from the NOAA/ESRL network and taking the SCIAMACHY averaging kernels into account. The comparisons address seasonal variations and long-term characteristics. The steady increase of atmospheric carbon dioxide primarily caused by the burning of fossil fuels can be clearly observed with SCIAMACHY globally. The retrieved annual mean XCO2 increase over both hemispheres agrees with CarbonTracker within the error bars but is on average somewhat smaller (1.8 ppm yr−1 compared to 1.9 ppm yr−1). The amplitude of the XCO2 seasonal cycle as retrieved by SCIAMACHY, which is 4.3 ppm for the Northern Hemisphere and 1.4 ppm for the Southern Hemisphere, is on average about 1 ppm larger than for CarbonTracker. An investigation of the boreal forest carbon uptake during the growing season via the analysis of longitudinal gradients shows good agreement between SCIAMACHY and CarbonTracker concerning the overall magnitude of the gradients and their annual variations. The retrieved XCH4 results show that after years of stability, atmospheric methane has started to rise again in recent years which is consistent with surface measurements. The largest increase is observed for the tropics and northern mid- and high-latitudes amounting to about 8 ppb yr−1 since 2007. Due care has been exercised to minimise the influence of detector degradation on the quantitative estimate of this anomaly.
Control of primary production in the Arctic by nutrients and light: insights from a high resolution ocean general circulation model
Authors: Popova E. E. , Yool A. , Coward A. C. , Aksenov Y. K. , Alderson S. G. , de Cuevas B. A. , Anderson T. R.
Published: November 2010

Abstract. Until recently, the Arctic Basin was generally considered to be a low productivity area and was afforded little attention in global- or even basin-scale ecosystem modelling studies. Due to anthropogenic climate change however, the sea ice cover of the Arctic Ocean is undergoing an unexpectedly fast retreat, exposing increasingly large areas of the basin to sunlight. As indicated by existing Arctic phenomena such as ice-edge blooms, this decline in sea-ice is liable to encourage pronounced growth of phytoplankton in summer and poses pressing questions concerning the future of Arctic ecosystems. It thus provides a strong impetus to modelling of this region. The Arctic Ocean is an area where plankton productivity is heavily influenced by physical factors. As these factors are strongly responding to climate change, we analyse here the results from simulations of the 1/4° resolution global ocean NEMO (Nucleus for European Modelling of the Ocean) model coupled with the MEDUSA (Model for Ecosystem Dynamics, carbon Utilisation, Sequestration and Acidification) biogeochemical model, with a particular focus on the Arctic basin. Simulated productivity is consistent with the limited observations for the Arctic, with significant production occurring both under the sea-ice and at the thermocline, locations that are difficult to sample in the field. Results also indicate that a substantial fraction of the variability in Arctic primary production can be explained by two key physical factors: (i) the maximum penetration of winter mixing, which determines the amount of nutrients available for summer primary production, and (ii) short-wave radiation at the ocean surface, which controls the magnitude of phytoplankton blooms. A strong empirical correlation was found in the model output between primary production and these two factors, highlighting the importance of physical processes in the Arctic Ocean.
First observations of global and seasonal terrestrial chlorophyll fluorescence from space
Authors: Joiner J. , Yoshida Y. , Vasilkov A. P. , Yoshida Y. , Corp L. A. , Middleton E. M.
Published: November 2010

Abstract. Remote sensing of terrestrial vegetation fluorescence from space is of interest because it can potentially provide global coverage of the functional status of vegetation. For example, fluorescence observations may provide a means to detect vegetation stress before chlorophyll reductions take place. Although there have been many measurements of fluorescence from ground- and airborne-based instruments, there has been scant information available from satellites. In this work, we use high-spectral resolution data from the Thermal And Near-infrared Sensor for carbon Observation – Fourier Transform Spectrometer (TANSO-FTS) on the Japanese Greenhouse gases Observing SATellite (GOSAT) that is in a sun-synchronous orbit with an equator crossing time near 13:00 LT. We use filling-in of the potassium (K) I solar Fraunhofer line near 770 nm to derive chlorophyll fluorescence and related parameters such as the fluorescence quantum yield at that wavelength. We map these parameters globally for two months (July and December 2009) and show a full seasonal cycle for several different locations, including two in the Amazonia region. We also compare the derived fluorescence information with that provided by the MODIS Enhanced Vegetation Index (EVI). These comparisons show that for several areas these two indices exhibit different seasonality and/or relative intensity variations, and that changes in fluorescence frequently lead those seen in the EVI for those regions. The derived fluorescence therefore provides information that is related to, but independent of the reflectance.
Biofabrication of Tissue‐Engineered Cartilage Constructs Through Faraday Wave Bioassembly of Cell‐Laden Gelatin Microcarriers
Authors: Zhu Jing , Luo Qiuchen , Yang Guang , Xiao Lin
Published: May 2024

Acoustic biofabrication is an emerging strategy in tissue engineering due to its mild and fast manufacturing process. Herein, tissue‐engineered cartilage constructs with high cell viability are fabricated from cell‐laden gelatin microcarriers (GMs) through Faraday wave bioassembly, a typical acoustic “bottom–up” manufacturing process. Assembly modules are first prepared by incorporating cartilage precursor cells, the chondrogenic cell line ATDC5, or bone marrow‐derived mesenchymal stem cells (BMSCs), into GMs. Patterned structures are formed by Faraday wave bioassembly of the cell‐laden GMs. Due to the gentle and efficient assembly process and the protective effects of microcarriers, cells in the patterned structures maintain high activity. Subsequently, tissue‐engineered cartilage constructs are obtained by inducing cell differentiation of the patterned structures. Comprehensive evaluations are conducted to verify chondrocyte differentiation and the formation of cartilage tissue constructs in terms of cell viability, morphological analysis, gene expression, and matrix production. Finally, implantation studies with a rat cartilage defect model demonstrate that these tissue‐engineered cartilage constructs are beneficial for the repair of articular cartilage damage in vivo. This study provides the first biofabrication of cartilage tissue constructs using Faraday wave bioassembly, extending its application to engineering tissues with a low cell density.
Natural Hydrogels Support Kidney Organoid Generation and Promote In Vitro Angiogenesis
Authors: Garreta Elena , Moya‐Rull Daniel , Marco Andrés , Amato Gaia , Ullate‐Agote Asier , Tarantino Carolina , Gallo Maria , Esporrín‐Ubieto David , Centeno Alberto , Vilas‐Zornoza Amaia , Mestre Rafael , Kalil María , Gorroñogoitia Izar , Zaldua Ane Miren , Sanchez Samuel , Izquierdo Reyes Laura , Fernández‐Santos María Eugenia , Prosper Felipe , Montserrat Nuria
Published: May 2024

To date, strategies aiming to modulate cell to extracellular matrix (ECM) interactions during organoid derivation remain largely unexplored. Here renal decellularized ECM (dECM) hydrogels are fabricated from porcine and human renal cortex as biomaterials to enrich cell‐to‐ECM crosstalk during the onset of kidney organoid differentiation from human pluripotent stem cells (hPSCs). Renal dECM‐derived hydrogels are used in combination with hPSC‐derived renal progenitor cells to define new approaches for 2D and 3D kidney organoid differentiation, demonstrating that in the presence of these biomaterials the resulting kidney organoids exhibit renal differentiation features and the formation of an endogenous vascular component. Based on these observations, a new method to produce kidney organoids with vascular‐like structures is achieved through the assembly of hPSC‐derived endothelial‐like organoids with kidney organoids in 3D. Major readouts of kidney differentiation and renal cell morphology are assessed exploiting these culture platforms as new models of nephrogenesis. Overall, this work shows that exploiting cell‐to‐ECM interactions during the onset of kidney differentiation from hPSCs facilitates and optimizes current approaches for kidney organoid derivation thereby increasing the utility of these unique cell culture platforms for personalized medicine.
One‐Shot Remote Integration of Macromolecular Synaptic Elements on a Chip for Ultrathin Flexible Neural Network System
Authors: Lee Jiyun , Lee Jaehoon , Bang Hyeonsu , Yoon Tae Woong , Ko Jong Hwan , Zhang Guobing , Park Ji‐Sang , Jeon Il , Lee Sungjoo , Kang Boseok
Published: May 2024

The field of biomimetic electronics that mimic synaptic functions has expanded significantly to overcome the limitations of the von Neumann bottleneck. However, the scaling down of the technology has led to an increasingly intricate manufacturing process. To address the issue, this work presents a one‐shot integrable electropolymerization (OSIEP) method with remote controllability for the deposition of synaptic elements on a chip by exploiting bipolar electrochemistry. Condensing synthesis, deposition, and patterning into a single fabrication step is achieved by combining alternating‐current voltage superimposed on direct‐current voltage‐bipolar electropolymerization and a specially designed dual source/drain bipolar electrodes. As a result, uniform 6 × 5 arrays of poly(3,4‐ethylenedioxythiophene) channels are successfully fabricated on flexible ultrathin parylene substrates in one‐shot process. The channels exhibited highly uniform characteristics and are directly used as electrochemical synaptic transistor with synaptic plasticity over 100 s. The synaptic transistors have demonstrated promising performance in an artificial neural network (NN) simulation, achieving a high recognition accuracy of 95.20%. Additionally, the array of synaptic transistor is easily reconfigured to a multi‐gate synaptic circuit to implement the principles of operant conditioning. These results provide a compelling fabrication strategy for realizing cost‐effective and disposable NN systems with high integration density.
Carbonated Beverage Chemistry for High‐Voltage Battery Cathodes
Authors: Liao Hengyi , Cai Mingzhi , Ma Wenqin , Cao Yuge , Zhao Siwei , Dong Yanhao , Huang Fuqiang
Published: May 2024

Advanced lithium‐ion batteries utilize high upper cut‐off voltages up to 4.8 V versus lithium metal to reach extraordinary energy densities. Such a harsh environment challenges the cathode stability and requires the construction of robust cathode electrolyte interphases at their electrochemical interface. Inspired by carbonated beverages with supersaturated CO2, here, a surface modification strategy that produces effective passivation layer of low modulus from the weakest link, is proposed CO2 bubbles preferentially nucleate and grow at rough surfaces, which in oxide cathodes, are also the local regions offering fast degradation pathway. Metal ion exchange on carbonated layer assists the construction of highly elastic interface under the guidance of packing factor. This method enables surface reconstruction at both primary and secondary particle levels for various cathodes exemplified by high‐voltage LiNi0.8Co0.1Mn0.1O2 (NCM811) and LiCoO2 (LCO). Remarkably, with ultra‐high upper cut‐off voltage of 4.8 V versus Li+/Li, over 235 mAh g−1 discharge capacity, and over 900 W h kg−1 discharge energy at cathode level, ≈90% capacity retention can be obtained for LiNi0.8Co0.1Mn0.1O2 over 100 cycles at 0.5 C with commercial carbonate electrolytes. This carbonated beverage chemistry is promising for constructing high‐quality surface passivation in many extreme‐condition applications beyond battery cathodes.
Thermal Shock Synthesis for Loading Sub‐2 nm Ru Nanoclusters on Titanium Nitride as a Remarkable Electrocatalyst toward Hydrogen Evolution Reaction
Authors: Zong Lingbo , Lu Fenghong , Li Ping , Fan Kaicai , Zhan Tianrong , Liu Porun , Jiang Lixue , Chen Dehong , Zhang Ruiyong , Wang Lei
Published: May 2024

Heterogeneous catalysts embracing metal entities on suitable supports are profound in catalyzing various chemical reactions, and substantial synthetic endeavors in metal–support interaction modulation are made to enhance catalytic performance. Here, it is reported the loading of sub‐2 nm Ru nanocrystals (NCs) on titanium nitride support (HTS‐Ru‐NCs/TiN) via a special Ru–Ti interaction using the high‐temperature shock (HTS) method. Direct dechlorination of the adsorbed RuCl3, ultrafast nucleation process, and short coalescence duration at ultrahigh temperatures contribute to the immobilization of Ru NCs on TiN support via producing the Ru–Ti interfacial perimeter. HTS‐Ru‐NCs/TiN shows remarkable activity toward hydrogen evolution reaction (HER) in alkaline solution, yielding ultralow overpotentials of 16.3 and 86.6 mV to achieve 10 and 100 mA cm−2, respectively. The alkaline and anion exchange membrane water electrolyzers assembled using HTS‐Ru‐NCs/TiN yield 1.0 A cm−2 at 1.65 and 1.67 V, respectively, which validate its applicability in the hydrogen production industry. Theoretical simulations reveal the favorable formation of Ru─O and Ti─H bonds at the interfacial perimeters between Ru NCs and TiN, which accelerates the prerequisite water dissociation kinetics for enhanced HER activity. This exemplified work motivates the design of specific interfacial perimeters via the HTS strategy to improve the performance of diverse catalysis.
Photosensitizer‐Amplified Antimicrobial Materials for Broad‐Spectrum Ablation of Resistant Pathogens in Ocular Infections
Authors: Lochenie Charles , Duncan Sheelagh , Zhou Yanzi , Fingerhut Leonie , Kiang Alex , Benson Sam , Jiang Guanyu , Liu Xiaogang , Mills Bethany , Vendrell Marc
Published: May 2024

The emergence of multidrug resistant (MDR) pathogens and the scarcity of new potent antibiotics and antifungals are one of the biggest threats to human health. Antimicrobial photodynamic therapy (aPDT) combines light and photosensitizers to kill drug‐resistant pathogens; however, there are limited materials that can effectively ablate different classes of infective pathogens. In the present work, a new class of benzodiazole‐paired materials is designed as highly potent PDT agents with broad‐spectrum antimicrobial activity upon illumination with nontoxic light. The results mechanistically demonstrate that the energy transfer and electron transfer between nonphotosensitive and photosensitive benzodiazole moieties embedded within pathogen‐binding peptide sequences result in increased singlet oxygen generation and enhanced phototoxicity. Chemical optimization renders PEP3 as a novel PDT agent with remarkable activity against MDR bacteria and fungi as well as pathogens at different stages of development (e.g., biofilms, spores, and fungal hyphae), which also prove effective in an ex vivo porcine model of microbial keratitis. The chemical modularity of this strategy and its general compatibility with peptide‐based targeting agents will accelerate the design of highly photosensitive materials for antimicrobial PDT.
Band Engineering of Perovskite Quantum Dot Solids for High‐Performance Solar Cells
Authors: Chen Jingxuan , Ye Lvhao , Wu Tai , Hua Yong , Zhang Xiaoliang
Published: May 2024

CsPbI3 perovskite quantum dot (PQD) shows high potential for next‐generation photovoltaics due to their tunable surface chemistry, good solution‐processability and unique photophysical properties. However, the remained long‐chain ligand attached to the PQD surface significantly impedes the charge carrier transport within the PQD solids, thereby predominantly influencing the charge extraction of PQD solar cells (PQDSCs). Herein, a ligand‐induced energy level modulation is reported for band engineering of PQD solids to improve the charge extraction of PQDSCs. Detailed theoretical calculations and systemic experimental studies are performed to comprehensively understand the photophysical properties of the PQD solids dominated by the surface ligands of PQDs. The results reveal that 4‐nitrobenzenethiol and 4‐methoxybenzenethiol molecules with different dipole moments can firmly anchor to the PQD surface through the thiol group to modulate the energy levels of PQDs, and a gradient band structure within the PQD solid is subsequently realized. Consequently, the band‐engineered PQDSC delivers an efficiency of up to 16.44%, which is one of the highest efficiencies of CsPbI3 PQDSCs. This work provides a feasible avenue for the band engineering of PQD solids by tuning the surface chemistry of PQDs for high‐performing solar cells or other optoelectronic devices.
Protocell Flow Reactors for Enzyme and Whole‐Cell Mediated Biocatalysis
Authors: Ma Huan , Liu Xiayi , Nobbs Angela H. , Mishra Ananya , Patil Avinash J. , Mann Stephen
Published: May 2024

The design and construction of continuous flow biochemical reactors comprising immobilized biocatalysts have generated great interest in the efficient synthesis of value‐added chemicals. Living cells use compartmentalization and reaction‐diffusion processes for spatiotemporal regulation of biocatalytic reactions, and implementing these strategies into continuous flow reactors can offer new opportunities in reactor design and application. Herein, the fabrication of protocell‐based continuous flow reactors for enzyme and whole‐cell mediated biocatalysis is demonstrated. Semipermeable membranized coacervate vesicles are employed as model protocells that spontaneously sequester enzymes or accumulate living bacteria to produce embodied microreactors capable of single‐ or multiple‐step catalytic reactions. By packing millions of the enzyme/bacteria‐containing coacervate vesicles in a glass column, a facile, cost‐effective, and modular methodology capable of performing oxidoreductase, peroxidase and lipolytic reactions, enzyme‐mediated L‐DOPA synthesis, and whole‐cell glycolysis under continuous flow conditions, is demonstrated. It is shown that the protocell‐nested enzymes and bacterial cells exhibit enhanced activities and stability under deleterious operating conditions compared with their non‐encapsulated counterparts. These results provide a step toward the engineering of continuous flow reactors based on cell‐like microscale agents and offer opportunities in the development of green and sustainable industrial bioprocessing.