bluuebunny/crossref_metadata_2025 huggingface dataset:
Children with cerebral malaria or severe malarial anaemia lack immunity to distinct variant surface antigen subsets
Authors: Travassos Mark A. , Niangaly Amadou , Bailey Jason A. , Ouattara Amed , Coulibaly Drissa , Lyke Kirsten E. , Laurens Matthew B. , Pablo Jozelyn , Jasinskas Algis , Nakajima Rie , Berry Andrea A. , Adams Matthew , Jacob Christopher G. , Pike Andrew , Takala-Harrison Shannon , Liang Li , Kouriba Bourema , Kone Abdoulaye K. , Rowe J. Alexandra , Moulds JoAnn , Diallo Dapa A. , Doumbo Ogobara K. , Thera Mahamadou A. , Felgner Philip L. , Plowe Christopher V.
Published: April 2018

Variant surface antigens (VSAs) play a critical role in severe malaria pathogenesis. Defining gaps, or “lacunae”, in immunity to these Plasmodium falciparum antigens in children with severe malaria would improve our understanding of vulnerability to severe malaria and how protective immunity develops. Using a protein microarray with 179 antigen variants from three VSA families as well as more than 300 variants of three other blood stage P. falciparum antigens, reactivity was measured in sera from Malian children with cerebral malaria or severe malarial anaemia and age-matched controls. Sera from children with severe malaria recognized fewer extracellular PfEMP1 fragments and were less reactive to specific fragments compared to controls. Following recovery from severe malaria, convalescent sera had increased reactivity to certain non-CD36 binding PfEMP1s, but not other malaria antigens. Sera from children with severe malarial anaemia reacted to fewer VSAs than did sera from children with cerebral malaria, and both of these groups had lacunae in their seroreactivity profiles in common with children who had both cerebral malaria and severe malarial anaemia. This microarray-based approach may identify a subset of VSAs that could inform the development of a vaccine to prevent severe disease or a diagnostic test to predict at-risk children.
A new family of periplasmic-binding proteins that sense arsenic oxyanions
Authors: Badilla Consuelo , Osborne Thomas H. , Cole Ambrose , Watson Cameron , Djordjevic Snezana , Santini Joanne M.
Published: April 2018

Arsenic contamination of drinking water affects more than 140 million people worldwide. While toxic to humans, inorganic forms of arsenic (arsenite and arsenate), can be used as energy sources for microbial respiration. AioX and its orthologues (ArxX and ArrX) represent the first members of a new sub-family of periplasmic-binding proteins that serve as the first component of a signal transduction system, that’s role is to positively regulate expression of arsenic metabolism enzymes. As determined by X-ray crystallography for AioX, arsenite binding only requires subtle conformational changes in protein structure, providing insights into protein-ligand interactions. The binding pocket of all orthologues is conserved but this alone is not sufficient for oxyanion selectivity, with proteins selectively binding either arsenite or arsenate. Phylogenetic evidence, clearly demonstrates that the regulatory proteins evolved together early in prokaryotic evolution and had a separate origin from the metabolic enzymes whose expression they regulate.
Genetic (idiopathic) epilepsy with photosensitive seizures includes features of both focal and generalized seizures
Authors: Xue Jiao , Gong Pan , Yang Haipo , Liu Xiaoyan , Jiang Yuwu , Zhang Yuehua , Yang Zhixian
Published: April 2018

Clinically, some patients having genetic (idiopathic) epilepsy with photosensitive seizures were difficult to be diagnosed. We aimed to discuss whether the genetic (idiopathic) epilepsy with photosensitive seizures is a focal entity, a generalized entity or a continuum. Twenty-two patients with idiopathic epilepsies and photoconvulsive response (PCR) were retrospectively recruited. In the medical records, the seizure types included “generalized tonic-clonic seizures (GTCS)” in 15, “partial secondarily GTCS (PGTCS)” in 3, partial seizures (PS) in 3, myoclonic seizures in 2, eyelid myoclonus in one, and only febrile seizures in one. Seizure types of PCR included GTCS (1/22), PGTCS (6/22), PS (9/22), electrical seizures (ES) (3/22) and GTCS/PGTCS (3/22). Combined the medical history with PCR results, they were diagnosed as: idiopathic (photosensitive) occipital lobe epilepsy (I(P)OE) in 12, genetic (idiopathic) generalized epilepsy (GGE) in one, GGE/I(P)OE in 5, pure photosensitive seizure in one, and epilepsy with undetermined generalized or focal seizure in 3. So, the dichotomy between generalized and focal seizures might have been out of date regarding to pathophysiological advances in epileptology. To some extent, it would be better to recognize the idiopathic epilepsy with photosensitive seizures as a continuum between focal and generalized seizures.
Spatial reversal learning defect coincides with hypersynchronous telencephalic BOLD functional connectivity in APPNL-F/NL-F knock-in mice
Authors: Shah Disha , Latif-Hernandez Amira , De Strooper Bart , Saito Takashi , Saido Takaomi , Verhoye Marleen , D’Hooge Rudi , Van der Linden Annemie
Published: April 2018

Amyloid pathology occurs early in Alzheimer’s disease (AD), and has therefore been the focus of numerous studies. Transgenic mouse models have been instrumental to study amyloidosis, but observations might have been confounded by APP-overexpression artifacts. The current study investigated early functional defects in an APP knock-in mouse model, which allows assessing the effects of pathological amyloid-beta (Aβ) without interference of APP-artifacts. Female APPNL/NL knock-in mice of 3 and 7 months old were compared to age-matched APPNL-F/NL-F mice with increased Aβ42/40 ratio and initial Aβ-plaque deposition around 6 months of age. Spatial learning was examined using a Morris water maze protocol consisting of acquisition and reversal trials interleaved with reference memory tests. Functional connectivity (FC) of brain networks was assessed using resting-state functional MRI (rsfMRI). The Morris water maze data revealed that 3 months old APPNL-F/NL-F mice were unable to reach the same reference memory proficiency as APPNL/NL mice after reversal training. This cognitive defect in 3-month-old APPNL-F/NL-F mice coincided with hypersynchronous FC of the hippocampal, cingulate, caudate-putamen, and default-mode-like networks. The occurrence of these defects in APPNL-F/NL-F mice demonstrates that cognitive flexibility and synchronicity of telencephalic activity are specifically altered by early Aβ pathology without changes in APP neurochemistry.
Mud extrusion and ring-fault gas seepage – upward branching fluid discharge at a deep-sea mud volcano
Authors: Loher M. , Pape T. , Marcon Y. , Römer M. , Wintersteller P. , Praeg D. , Torres M. , Sahling H. , Bohrmann G.
Published: April 2018

Submarine mud volcanoes release sediments and gas-rich fluids at the seafloor via deeply-rooted plumbing systems that remain poorly understood. Here the functioning of Venere mud volcano, on the Calabrian accretionary prism in ~1,600 m water depth is investigated, based on multi-parameter hydroacoustic and visual seafloor data obtained using ship-borne methods, ROVs, and AUVs. Two seepage domains are recognized: mud breccia extrusion from a summit, and hydrocarbon venting from peripheral sites, hosting chemosynthetic ecosystems and authigenic carbonates indicative of long-term seepage. Pore fluids in freshly extruded mud breccia (up to 13 °C warmer than background sediments) contained methane concentrations exceeding saturation by 2.7 times and chloride concentrations up to five times lower than ambient seawater. Gas analyses indicate an underlying thermogenic hydrocarbon source with potential admixture of microbial methane during migration along ring faults to the peripheral sites. The gas and pore water analyses point to fluids sourced deep (>3 km) below Venere mud volcano. An upward-branching plumbing system is proposed to account for co-existing mud breccia extrusion and gas seepage via multiple surface vents that influence the distribution of seafloor ecosystems. This model of mud volcanism implies that methane-rich fluids may be released during prolonged phases of moderate activity.
Native collagen hydrogel nanofibres with anisotropic structure using core-shell electrospinning
Authors: Wakuda Yuka , Nishimoto Shohei , Suye Shin-ichiro , Fujita Satoshi
Published: April 2018

Collagen hydrogel is a popular extracellular matrix (ECM) material in regenerative medicine and has an isotropic structure. In contrast, native ECM has an anisotropic structure. Electrospinning of collagen dissolved in organic solvents is widely used for fabricating anisotropic collagen nanofibres; however, such fibres are water-soluble and require cross-linking before use as scaffolds for cell culture. Herein, electrospinning using a core-shell nozzle was employed to spin an aqueous acidic solution of collagen and encapsulate it within a shell of polyvinylpyrrolidone (PVP). Subsequently, the core collagen was gelled, and the shell PVP was washed away using a basic ethanol solution to yield anisotropic collagen hydrogel nanofibres. Immunostaining and Fourier transform infrared spectroscopy revealed that the obtained fibres were composed of collagen, and surface PVP was removed completely. Circular dichroism measurements confirmed that the fibres exhibited the triple helical structure characteristic of collagen. Human umbilical vein endothelial cells cultured on the collagen hydrogel fibres were oriented along the fibre direction. Hence, this method is suitable for fabricating fibrous anisotropic collagen hydrogels without chemical and thermal cross-linking, and can facilitate the development of safe medical materials with anisotropy similar to that of native ECM.
A Mixed Periodic Paralysis & Myotonia Mutant, P1158S, Imparts pH-Sensitivity in Skeletal Muscle Voltage-gated Sodium Channels
Authors: Ghovanloo Mohammad-Reza , Abdelsayed Mena , Peters Colin H. , Ruben Peter C.
Published: April 2018

Skeletal muscle channelopathies, many of which are inherited as autosomal dominant mutations, include myotonia and periodic paralysis. Myotonia is defined by a delayed relaxation after muscular contraction, whereas periodic paralysis is defined by episodic attacks of weakness. One sub-type of periodic paralysis, known as hypokalemic periodic paralysis (hypoPP), is associated with low potassium levels. Interestingly, the P1158S missense mutant, located in the third domain S4-S5 linker of the “skeletal muscle”, Nav1.4, has been implicated in causing both myotonia and hypoPP. A common trigger for these conditions is physical activity. We previously reported that Nav1.4 is relatively insensitive to changes in extracellular pH compared to Nav1.2 and Nav1.5. Given that intense exercise is often accompanied by blood acidosis, we decided to test whether changes in pH would push gating in P1158S towards either phenotype. Our results suggest that, unlike in WT-Nav1.4, low pH depolarizes the voltage-dependence of activation and steady-state fast inactivation, decreases current density, and increases late currents in P1185S. Thus, P1185S turns the normally pH-insensitive Nav1.4 into a proton-sensitive channel. Using action potential modeling we predict a pH-to-phenotype correlation in patients with P1158S. We conclude that activities which alter blood pH may trigger the noted phenotypes in P1158S patients.
Functionalized magnetic nanoparticles: Synthesis, characterization, catalytic application and assessment of toxicity
Authors: Neamtu Mariana , Nadejde Claudia , Hodoroaba Vasile-Dan , Schneider Rudolf J. , Verestiuc Liliana , Panne Ulrich
Published: April 2018

Cost-effective water cleaning approaches using improved treatment technologies, for instance based on catalytic processes with high activity catalysts, are urgently needed. The aim of our study was to synthesize efficient Fenton-like photo-catalysts for rapid degradation of persistent organic micropollutants in aqueous medium. Iron-based nanomaterials were chemically synthesized through simple procedures by immobilization of either iron(II) oxalate (FeO) or iron(III) citrate (FeC) on magnetite (M) nanoparticles stabilized with polyethylene glycol (PEG). Various investigation techniques were performed in order to characterize the freshly prepared catalysts. By applying advanced oxidation processes, the effect of catalyst dosage, hydrogen peroxide concentration and UV-A light exposure were examined for Bisphenol A (BPA) conversion, at laboratory scale, in mild conditions. The obtained results revealed that BPA degradation was rapidly enhanced in the presence of low-concentration H2O2, as well as under UV-A light, and is highly dependent on the surface characteristics of the catalyst. Complete photo-degradation of BPA was achieved over the M/PEG/FeO catalyst in less than 15 minutes. Based on the catalytic performance, a hierarchy of the tested catalysts was established: M/PEG/FeO > M/PEG/FeC > M/PEG. The results of cytotoxicity assay using MCF-7 cells indicated that the aqueous samples after treatment are less cytotoxic.
Author Correction: Sensitivity enhancement of flexible gas sensors via conversion of inkjet-printed silver electrodes into porous gold counterparts
Authors: Fang Yunnan , Akbari Mitra , Hester Jimmy G. D. , Sydänheimo Lauri , Ukkonen Leena , Tentzeris Manos M.
Published: April 2018

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.
Improving general chemistry performance through a growth mindset intervention: selective effects on underrepresented minorities
Authors: Fink Angela , Cahill Michael J. , McDaniel Mark A. , Hoffman Arielle , Frey Regina F.
Published: April 2018

Women and minorities remain underrepresented in chemistry bachelor's degree attainment in the United States, despite efforts to improve their early chemistry achievement through supplemental academic programs and active-learning approaches. We propose an additional strategy for addressing these disparities: course-based, social-psychological interventions. For example, growth-mindset interventions are designed to support students during challenging academic transitions by encouraging them to view intelligence as a flexible characteristic that can be developed through practice, rather than a fixed ability. Previous research has shown that such interventions can improve the overall performance and persistence of college students, particularly those who belong to underrepresented groups. We report a random-assignment classroom experiment, which implemented a chemistry-specific growth-mindset intervention among first-year college students enrolled in General Chemistry 1. Performance results revealed an achievement gap between underrepresented minority and white students in the control group, but no sex-based gap. Critically, after adjusting for variation in academic preparation, the mindset intervention eliminated this racial-achievement gap. Qualitative analysis of students’ written reflections from the intervention shed light on their experiences of the mindset and control treatments, deepening our understanding of mindset effects. We integrate these results with the mindset and chemical education literatures and discuss the implications for educators seeking to support underrepresented students in their own classrooms.
Single-walled carbon nanotube/polystyrene core–shell hybrids: synthesis and photoluminescence properties
Authors: Orcin-Chaix L. , Trippé-Allard G. , Voisin C. , Okuno H. , Derycke V. , Lauret J.-S. , Campidelli S.
Published: April 2018

Core–shell structures made of SWNTs and polystyrene are synthesized; the hybrids can be easily manipulated in solution and exhibit photoluminescence in film.
Synthesis, characterization and biological evaluation of Pd(ii), Cu(ii), Re(i) and 99mTc(i) thiazole-based complexes
Authors: Mašković Jelena M. , Hatzidimitriou Antonios , Damjanović Ana , Stanojković Tatjana P. , Trifunović Srećko R. , Geronikaki Athina A. , Papagiannopoulou Dionysia
Published: April 2018

Synthesis and evaluation of antitumoral, antiinflammatory or inflammation-targeted properties of Pd(ii), Cu(ii), Re(i), and 99mTc(i) thiazole-based complexes is presented.
Self-powered photogalvanic phosphorene photodetectors with high polarization sensitivity and suppressed dark current
Authors: Li Shuaishuai , Wang Tao , Chen Xiaoshuang , Lu Wei , Xie Yiqun , Hu Yibin
Published: April 2018

Self-powered phosphorene-based photodetectors driven by photogalvanic effects are proposed theoretically.
Zwitterionic diketopyrrolopyrrole for fluorescence/photoacoustic imaging guided photodynamic/photothermal therapy
Authors: Deng Weixing , Wu Qi , Sun Pengfei , Yuan Pengcheng , Lu Xiaomei , Fan Quli , Huang Wei
Published: April 2018

Water-soluble zwitterionic diketopyrrolopyrrole (DPP-SPMA) for fluorescence/photoacoustic imaging guided photodynamic/photothermal therapy with favorable renal excretion and ultralow cytotoxicity.
Bio-based poly(hydroxyurethane) glues for metal substrates
Authors: Panchireddy Satyannarayana , Grignard Bruno , Thomassin Jean-Michel , Jerome Christine , Detrembleur Christophe
Published: April 2018

Bio- and CO2-based high performance thermoset poly(hydroxyurethane) (PHU) glues were designed from solvent- and isocyanate-free formulations based on cyclocarbonated soybean oil, diamines (aliphatic, cycloaliphatic or aromatic) and functional silica or ZnO fillers.
Analysis on the energetics, magnetism and electronic properties in a 45° ZnO grain boundary doped with Gd
Authors: Sasikala Devi Assa Aravindh , Roqan Iman S.
Published: April 2018

The structural stability and magnetic properties of a grain boundary (GB) formed by two ZnO single crystals oriented at 45° is investigated by density functional theory, using generalized gradient approximation (GGA) with Hubbard parameter (U).
Taming a monomeric [Cu(η6-C6H6)]+ complex with silylene
Authors: Parvin Nasrina , Pal Shiv , Echeverría Jorge , Alvarez Santiago , Khan Shabana
Published: April 2018

Realization of a hitherto elusive unsupported η6 binding mode of benzene to a copper(i) cation employing silylene as a ligand. The back-donation from Cu to Si(ii) diminishes the repulsion between d-electrons and the benzene ring and enforces the η6 binding mode.
Low-temperature and facile solution-processed two-dimensional TiS2 as an effective electron transport layer for UV-stable planar perovskite solar cells
Authors: Yin Guannan , Zhao Huan , Feng Jiangshan , Sun Jie , Yan Junqing , Liu Zhike , Lin Shenghuang , Liu Shengzhong (Frank)
Published: April 2018

In this paper, it is demonstrated that two-dimensional TiS2 nanosheets can be applied as an effective ETL in planar PSCs for the first time.
SiOC nanolayer wrapped 3D interconnected graphene sponge as a high-performance anode for lithium ion batteries
Authors: Sang Zhiyuan , Zhao Zhihao , Su Dong , Miao Peishuang , Zhang Fengrui , Ji Huiming , Yan Xiao
Published: April 2018

A SiOC nanolayer wrapped 3D interconnected GNS conductive framework contributed to the best ever reported high-performance for SiOC-based anode materials.
An unusual low-surface-area nitrogen doped carbon for ultrahigh gravimetric and volumetric capacitances
Authors: Mao Zhan Xin , Wang Changyao , Shan Qianyuan , Wang Min Jie , Zhang Yuxin , Ding Wei , Chen Siguo , Li Li , Li Jing , Wei Zidong
Published: April 2018

An unusual low-surface-area N-doped carbon with nice performances of 400 F g−1 and 507 F cm−3, for gravimetric and volumetric capacitances respectively, has been extensively investigated to reveal the structural features.
A–D–A small molecule acceptors with ladder-type arenes for organic solar cells
Authors: He Dan , Zhao Fuwen , Jiang Li , Wang Chunru
Published: April 2018

A–D–A small molecule acceptors possess strong absorption in the visible or NIR region, low bandgaps, relatively high electron mobility and proper miscibility with donors, which enables the achievement of high power conversion efficiency for organic solar cells based on these molecules.
A synergistic polyphosphoester-based co-delivery system of the anticancer drug doxorubicin and the tumor suppressor gene p53 for lung cancer therapy
Authors: Liu Jie , He Jinlin , Zhang Mingzu , Xu Guoqiang , Ni Peihong
Published: April 2018

Hybrid micelles composed of polymeric prodrug and gene carrier were constructed by polyphosphoester-based co-delivery system for lung cancer therapy.
The impact of a changing atmosphere on chloroplast function, photosynthesis, yield, and food security
Authors: Gutteridge Steven
Published: April 2018

A convergence of global factors is adding to the difficulties of securing a sustainable supply of food and feed to support the increasing global population. The positive impact of the rise in atmospheric CO2 on photosynthesis is more than offset by the increase in average global temperatures accompanying the change in atmospheric composition. This article provides a brief overview of how these adverse events affect some of the critical molecular processes of the chloroplast and by extension how this impacts the yields of the major crops. Although the tools are available to introduce genetic elements in most crops that will mitigate these adverse factors, the time needed to validate and optimize these traits can be extensive. There is a major concern that at the current rate of change to atmospheric composition and the accompanying rise in temperature the benefits of these traits may be rendered less effective soon after their introduction.
Combined control method for grid‐side converter of doubly fed induction generator‐based wind energy conversion systems
Authors: Mohammadi Jafar , Vaez‐Zadeh Sadegh , Ebrahimzadeh Esmaeil , Blaabjerg Frede
Published: April 2018

This study proposes a combined control method based on vector control (VC) and virtual flux direct power control (VFDPC) for grid‐side converter of doubly fed induction generator (DFIG)‐based wind energy conversion systems (WECSs). VC gives lower power ripple with a slower dynamic response, while VFDPC provides a faster dynamic response, but higher power ripple. So, an analogy between VC and VFDPC is proved first and then used to propose a combined control method that takes the advantages of VC and VFDPC in an integrated control system. In the combined control method, the grid currents are directly controlled using hysteresis controllers and optimal switching table. It has several advantages compared to VC including faster power/current dynamic response, robustness to grid filter parameter variation, lower computation, and simple implementation. On the other hand, its advantages compared to VFDPC include less current harmonic distortion, lower power ripple, and robustness to measurement noise. To demonstrate the effectiveness and robustness of the combined control method, simulation results on a 1.5 MW DFIG‐based WECS are provided and compared with both VC and VFDPC under different steady‐state and transient conditions. The simulation results verify the superiority of the proposed method over either VC or VFDPC.
Design and analysis of hairpin piezoresistive pressure sensor with improved linearity using square and circular diaphragms
Authors: Hayati Mohsen , Fathipour Morteza , Sherafat Vaziri Hamid
Published: April 2018

A novel structure for piezoresistive pressure sensors is proposed. The structure comprises two piezo‐resistors, one mounted on a flat diaphragm and the other mounted outside of the diaphragm so that a hairpin‐shaped structure is formed. As a result, one of the piezo‐resistors will be affected by the input pressure and the other one will not. Also an inverting Operational Amplifier (OP‐AMP) amplifier is utilised. The proposed pressure sensor can be designed using both square diaphragm or circular diaphragm and it has the advantage of higher linearity for input pressure range of 1 MPa in comparison with conventional structures. The value of nonlinearity (NL) is decreased from 0.5515% full‐scale (FS), for the conventional sensor, to 0.1138% FS (for the proposed sensor with square diaphragm) and 0.0761% FS (for the proposed sensor with circular diaphragm), which shows an improvement in reducing NL about 80% in square diaphragm and about 86% when circular diaphragm is employed. The proposed structure is analysed and simulated using COMSOL multiphysics software.
Spectral variation of suprathermal protons associated with stream interaction regions: STEREO A/PLASTIC observations
Authors: Yu J. , Berger L. , Drews C. , Wimmer-Schweingruber R. , Taut A.
Published: April 2018

Context. The observation of power-law spectra of suprathermal particles is typically associated with the occurrence of stream interaction regions (SIRs), indicating that these particles are accelerated close to the observer. However, recent observations have identified the existence of sunwards streaming particles at low suprathermal energies following SIRs. In addition, the observational evidence for turnover spectra in the low suprathermal energies has also been presented, suggesting that these particles might be accelerated at remote shocks and travel back to the Sun along the interplanetary magnetic field lines.

Aims. We investigate the spectral evolution and variation of suprathermal protons from SIR to SIR as the observer moves from inside the compression regions of SIRs to the outside undisturbed solar wind regions away from the reverse shocks.

Methods. The spectral analysis in the range from solar wind to suprathermal energies was based on proton data, which are obtained by the Plasma and Suprathermal Ion Composition instrument (PLASTIC) on the Solar Terrestrial Relations Observatory mission (STEREO).

Results. All spectra in the compressed fast wind regions (F′ regions) of twelve SIRs exhibit power-law suprathermal tails. Six of them show clear turnover spectra at velocities below 2500 km s−1 in the undisturbed fast solar wind regions (F regions) following the compression regions, while the remaining six events exhibit continuous power-law spectra. Overall, the spectra at velocities higher than 2500 km s−1 harden in the F regions, consistent with previous observations.
Performances of a HGCDTE APD based direct detection lidar at 2 μm. Application to dial measurements
Authors: Gibert Fabien , Dumas Arnaud , Rothman Johan , Edouart Dimitri , Cénac Claire , Pellegrino Jessica
Published: April 2018

A lidar receiver with a direct detection chain adapted to a HgCdTe APD based detector with electric cooling is associated to a 2.05 μm Ho :YLF pulsed dual wavelength single mode transmitter to provide the first atmospheric lidar measurements using this technology. Experiments confirm the outstanding sensitivity of the detector and hightligth its huge potential for DIAL measurements of trace gas (CO2 and H2O) in this spectral domain. Performances of coherent vs direct detection at 2.05 μm is assessed.
Lidar sprectroscopy instrument (LISSI): An infrastructure facility for chemical aerosol profiling at the University of Hertfordshire
Authors: Tesche Matthias , Tatarov Boyan , Noh Youngmin , Müller Detlef
Published: April 2018

The lidar development at the University of Hertfordshire explores the feasibility of using Raman backscattering for chemical aerosol profiling. This paper provides an overview of the new facility. A high-power Nd:YAG/OPO setup is used to excite Raman backscattering at a wide range of wavelengths. The receiver combines a spectrometer with a 32-channel detector or an ICCD camera to resolve Raman signals of various chemical compounds.

The new facility will open new avenues for chemical profiling of aerosol pollution from measurements of Raman scattering by selected chemical compounds, provide data that allow to close the gap between optical and microphysical aerosol profiling with lidar and enables connecting lidar measurements to parameters used in atmospheric modelling.
First application of the optimal estimation method to retrieve temperature from pure rotational raman scatter lidar measurements
Authors: Gamage S. Mahagammulla , Haefele A. , Sica R.J.
Published: April 2018

We present the application of the Optimal Estimation Method (OEM) to retrieve atmospheric temperatures from pure rotational Raman (PRR) backscatter lidar measurements. A forward model (FM) is developed to retrieve temperature and tested using synthetic measurements. The OEM offers many advantages for this analysis, including eliminating the need to determine temperature calibration coefficients.
CW Laser radar for combustion diagnostics
Authors: Malmqvist Elin , Brydegaard Mikkel , Aldén Marcus , Bood Joakim
Published: April 2018

A CW-laser radar system developed for combustion diagnostics is described. The system is based on triangulation to attain range information. A portable system has been constructed and here we show some result from measurements in various flames, for example Rayleigh scattering thermometry and monitoring of particle distributions with high temporal and spatial resolution. The concept can equally well be based on pulsed lasers, allowing suppression of background emission through gated detection.
Raman spectroscopy measurement of CH4 gas and CH4 dissolved in water for laser remote sensing in water
Authors: Somekawa Toshihiro , Fujita Masayuki
Published: April 2018

We examined the applicability of Raman spectroscopy as a laser remote sensing tool for monitoring CH4 in water. The Raman technique has already been used successfully for measurements of CO2 gas in water. In this paper, considering the spectral transmittance of water, third harmonics of Q-switched Nd:YAG laser at 355 nm (UV region) was used for detection of CH4 Raman signals. The Raman signal at 2892 cm-1 from CH4 dissolved in water was detected at a tail of water Raman signal.
Advances in atmospheric temperature profile measurements using high spectral resolution lidar
Authors: Razenkov Ilya I. , Eloranta Edwin W.
Published: April 2018

This paper reports the atmospheric temperature profile measurements using a University of Wisconsin-Madison High Spectral Resolution Lidar (HSRL) and describes improvements in the instrument performance. HSRL discriminates between Mie and Rayleigh backscattering [1]. Thermal motion of molecules broadens the spectrum of the transmitted laser light due to Doppler effect. The HSRL exploits this property to allow the absolute calibration of the lidar and measurements of the aerosol volume backscatter coefficient. Two iodine absorption filters with different line widths are used to resolve temperature sensitive changes in Rayleigh backscattering for atmospheric temperature profile measurements.
High spectral resolution lidar at the university of wisconsin-madison
Authors: Razenkov Ilya I. , Eloranta Edwin W.
Published: April 2018

This paper describes the modifications done on the University of Wisconsin-Madison High Spectral Resolution Lidar (HSRL) that improved the instrument’s performance. The University of Wisconsin HSRL lidars designed by our group at the Space Science and Engineering Center were deployed in numerous field campaigns in various locations around the world. Over the years the instruments have undergone multiple modifications that improved the performance and added new measurement capabilities such as atmospheric temperature profile and extinction cross-section measurements.
How to apply the optimal estimation method to your lidar measurements for improved retrievals of temperature and composition
Authors: Sica R. J. , Haefele A. , Jalali A. , Gamage S. , Farhani G.
Published: April 2018

The optimal estimation method (OEM) has a long history of use in passive remote sensing, but has only recently been applied to active instruments like lidar. The OEM’s advantage over traditional techniques includes obtaining a full systematic and random uncertainty budget plus the ability to work with the raw measurements without first applying instrument corrections. In our meeting presentation we will show you how to use the OEM for temperature and composition retrievals for Rayleigh-scatter, Ramanscatter and DIAL lidars.
New laser design for NIR lidar applications
Authors: Vogelmann H. , Trickl T. , Perfahl M . , Biggel S.
Published: April 2018

Recently, we quantified the very high spatio-temporal short term variability of tropospheric water vapor in a three dimensional study [1]. From a technical point of view this also depicted the general requirement of short integration times for recording water-vapor profiles with lidar. For this purpose, the only suitable technique is the differential absorption lidar (DIAL) working in the near-infrared (NIR) spectral region. The laser emission of most water vapor DIAL systems is generated by Ti:sapphire or alexandrite lasers. The water vapor absorption band at 817 nm is predominated for the use of Ti:sapphire. We present a new concept of transversely pumping in a Ti:Sapphire amplification stage as well as a compact laser design for the generation of single mode NIR pulses with two different DIAL wavelengths inside a single resonator. This laser concept allows for high output power due to repetitions rates up to 100Hz or even more. It is, because of its compactness, also suitable for mobile applications.
Reduction of multiple scattering to second order scattering for determination of liquid-cloud microphysical properties
Authors: Cao Xiaoying , Roy Gilles , Tremblay Grégoire
Published: April 2018

Under single scattering conditions, water droplets clouds do not depolarize the backscattered light. However, backscattered light from multiple scattering will be depolarized. The level of depolarization is a function of the droplets size and of the cloud extinction coefficient value and its profile; it has also a strong dependency on the lidar field-of-view (FOV) and azimuth angle [1]-[3]. It has been demonstrated in [4] that the multiple scattering cross polarization signal can be reduced to a second order scattering one using the azimuthal dependency of the cross polarization. In this paper we present how the multiple scattering cross polarization can be reduced to a second order scattering and how this signal is related to the droplet particle size. Monte Carlo simulations for clouds at different ranges and effective radius sizes are performed and compared with the results obtained with an analytical model.
Comparison between two lidar methods to retrieve microphysical properties of liquid-water clouds
Authors: Jimenez Cristofer , Ansmann Albert , Donovan David , Engelmann Ronny , Schmidt Jörg , Wandinger Ulla
Published: April 2018

Since 2010, the Raman dual-FOV lidar system permits the retrieval of microphysical properties of liquid-water clouds during nighttime. A new robust lidar depolarization approach was recently introduced, which permits the retrieval of these properties as well, with high temporal resolution and during daytime. To implement this approach, the lidar system was upgraded, by adding a three channel depolarization receiver. The first preliminary retrieval results and a comparison between both methods is presented.
Lidar to determine the fractions of ice, liquid and water vapor in polar tropospheric clouds
Authors: Fochesatto Gilberto J. , Galvez Oscar , Ristori Pablo , Keller Douglas , Fochesatto Enzo
Published: April 2018

A new Lidar combining Raman spectroscopy and linear polarization analysis is presented. This new instrument identifies the fraction of ice, liquid, and water vapor in low level polar tropospheric clouds and provides the polarimetric S and P state of the backscattering 532 nm Lidar signal. An overview of the research applications is given followed by a theoretical estimation of the Lidar returns. The instrument concept and optical characteristics are discussed. First Lidar profiles and instrument evaluations will be provided during the conference.
Space-borne profiling of atmospheric thermodynamic variables with raman lidar
Authors: Di Girolamo Paolo , Behrendt Andreas , Wulfmeyer Volker
Published: April 2018

The performance of a space-borne water vapour and temperature Raman lidar has been simulated, with a specific attention to the Earth Explorer Missions in the frame of ESA's Living Planet Program. We report simulations under a variety of atmospheric scenarios, demonstrating the capability of a space Raman lidar to provide global-scale water vapour and temperature measurements in the troposphere with an accuracy fulfilling most observational requirements for numerical weather prediction (NWP) and climate research.
Enhancements to the caliop aerosol subtyping and lidar ratio selection algorithms for level II version 4
Authors: Omar A. , Tackett J. , Kim M-H. , Vaughan M. , Kar J. , Trepte C. , Winker D.
Published: April 2018

Several enhancements have been implemented for the version 4 aerosol subtyping and lidar ratio selection algorithms of Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP). Version 4 eliminates the confusion between smoke and clean marine aerosols seen in version 3 by modifications to the elevated layer flag definitions used to identify smoke aerosols over the ocean. To differentiate between mixtures of dust and smoke, and dust and marine aerosols, a new aerosol type will be added in the version 4 data products. In the marine boundary layer, moderately depolarizing aerosols are no longer modeled as mixtures of dust and smoke (polluted dust) but rather as mixtures of dust and seasalt (dusty marine). Some lidar ratios have been updated in the version 4 algorithms. In particular, the dust lidar ratios have been adjusted to reflect the latest measurements and model studies.
A compact led lidar system fitted for a mars rover – design and ground experiment
Authors: Ong Prane Mariel B. , Shiina Tatsuo , Manago Naohiro , Kuze Hiroaki , Senshu Hiroki , Otobe Naohito , Hashimoto George , Kawabata Yasuhiro
Published: April 2018

A compact LED lidar was constructed and fieldtested with the aim to observe the Mars’ dust devils. To be able to fit it on the Mars rover, a specialized Cassegrain telescope was designed to be within a 10 cm-cube, with a field of view of 3mrad. The transmitter has 385 nm LED light source with 3 cmϕ opening, 70mrad divergence, 0.75W (7.5nJ/10ns) pulse power, and 500 kHz repetition frequency. The configuration of the optical system is biaxial to easily configure the overlap between their optical axes.
Aerosol optical properties retrieved from the future space lidar mission ADM-aeolus
Authors: Martinet Pauline , Flament Thomas , Dabas Alain
Published: April 2018

The ADM-Aeolus mission, to be launched by end of 2017, will enable the retrieval of aerosol optical properties (extinction and backscatter coefficients essentially) for different atmospheric conditions. A newly developed feature finder (FF) algorithm enabling the detection of aerosol and cloud targets in the atmospheric scene has been implemented. Retrievals of aerosol properties at a better horizontal resolution based on the feature finder groups have shown an improvement mainly on the backscatter coefficient compared to the common 90 km product.
Characterization of atmospheric thermodynamic variables by Raman lidar in the frame of the International Network for the Detection of Atmospheric Composition Change - NDACC
Authors: De Rosa Benedetto , Di Girolamo Paolo , Summa Donato
Published: April 2018

In November 2012 the Raman Lidar system BASIL, located at the Univ. of Basilicata (Potenza), was approved to enter in NDACC, with the goal of providing accurate routine measurements of the vertical profiles of atmospheric temperature and water vapour mixing ratio. In this presentation we illustrate and discuss water vapour mixing ratio and temperature measurements carried out during these four years and their comparisons with the radiosondes launched from nearby Institute IMAA-CNR (7 km away).
Monitoring the industrial sources of aerosol in Cubatao, Brazil, using a scanning elastic lidar and a lidar doppler
Authors: da Costa Renata F. , Marques Marcia T. A. , M Macedo Fernanda de , Andrade Izabel da Silva , Araujo Elaine Cristina , Correa Thais , de Andrade Salani Maria Helena Goncalves , Lopes Daniel Silveira , Goncalves Guardani Maria Lucia , Landulfo Eduardo , Guardani Roberto
Published: April 2018

Field campaigns with a scanning multiwavelength elastic lidar coupled with a Doppler system to monitor industrial atmospheric aerosol emissions were carried out, with the objective of monitoring aerosol emission sources and plume dispersion. Since the technique provides information on the spatial and temporal distribution of aerosol concentration, the implementation of a systematic monitoring procedure is proposed as a valuable tool in air quality monitoring applied to regions of interest.
Measurements of Water Vapor Profiles with Compact DIAL in the Tokyo Metropolitan Area
Authors: Abo Makoto , Sakai Tetsu , Le Hoai Phong Pham , Shibata Yasukuni , Nagasawa Chikao
Published: April 2018

In recent years, the frequency of occurrence of locally heavy rainfall that can cause extensive damages, has been increasing in Japan. For early prediction of heavy rainfall, it is useful to measure the water vapor vertical distribution upwind cumulus convection beforehand. For that purpose, we have been developing compact water vapor differential absorption lidar (DIAL).

We show the results of the measurements with lidar in summer when the local heavy rainfall frequently occurs in Japan. We also show the preliminary result of the assimilation of the lidar data to the numerical model and impact on the heavy rainfall prediction.
Airborne Two-Micron Double-Pulse IPDA Lidar Validation for Carbon Dioxide Measurements Over Land
Authors: Refaat Tamer F. , Singh Upendra N. , Yu Jirong , Petros Mulugeta , Remus Ruben , Ismail Syed
Published: April 2018

An airborne double-pulse 2-μm Integrated Path Differential Absorption (IPDA) lidar has been developed at NASA LaRC for measuring atmospheric CO2. IPDA was validated using NASA B-200 aircraft over land and ocean under different conditions. IPDA evaluation for land vegetation returns, during full day background conditions, are presented. IPDA CO2 measurements compare well with model results driven from on-board insitu sensor data. These results also indicate that CO2 measurement bias is consistent with that from ocean surface returns.
TWOMEY EFFECT IN SUBTROPICAL STRATOCUMULUS CLOUDS FROM UV DEPOLARIZATION LIDAR
Authors: de Graaf Martin , Brown Jessica , Donovan David
Published: April 2018

Marine stratocumulus clouds are important climate regulators, reflecting sunlight over a dark ocean background. A UV-depolarization lidar on Ascension, a small remote island in the south Atlantic, measured cloud droplet sizes and number concentration using an inversion method based on Monte Carlo (MC) modelling of multiple scattering in idealised semiadiabatic clouds. The droplet size and number concentration weremodulated due to smoke from the African continent, measured by the same instrument.
Micro-pulse, differential absorption lidar (dial) network for measuring the spatial and temporal distribution of water vapor in the lower atmosphere
Authors: Spuler Scott , Repasky Kevin , Hayman Matt , Nehrir Amin
Published: April 2018

The National Center for Atmospheric Research (NCAR) and Montana State Univeristy (MSU) are developing a test network of five micro-pulse differential absorption lidars to continuously measure high-vertical-resolution water vapor in the lower atmosphere. The instruments are accurate, yet low-cost; operate unattended, and eye-safe – all key features to enable the larger network needed to characterize atmospheric moisture variability which influences important processes related to weather and climate.
Greenlite™: a year of carbon dioxide monitoring over paris, france, and recent progress in monitoring methane
Authors: Dobler Jeremy , Zaccheo T. Scott , Pernini Timothy , Blume Nathan , Braun Michael
Published: April 2018

GreenLITE™ is a ground-based laser absorption spectroscopy system capable of measuring and mapping CO2 concentrations over areas up to 25 km2. The system was deployed for COP21 as a demonstration and has now completed a year of CO2 measurements over the city of Paris, France. We will discuss lessons learned and relevant data from the year-long deployment. Recently, the system has demonstrated the same measurement capability for CH4, and results from preliminary testing are presented.
Detection of saharan mineral dust aerosol transport over brazilian northeast through a depolarization lidar
Authors: Guedes Anderson G. , Landulfo Eduardo , Montilla-Rosero Elena , Lopes Fábio J.S. , Hoelzemann Judith J. , Fernandez José Henrique , Silva Marcos P. A. , Santos Renata S. S. , Guerrero-Rascado Juan L. , Alados-Arboledas Lucas
Published: April 2018

In this study we present results of linear volume depolarization ratio profiles obtained by a depolarization lidar in operation in Natal, Brazil. The DUSTER system has 4 channels, namely: 1064, 532 s/p and 355 nm. This system is calibrated with a half-wave plate using the Δ90° methodology. The data obtained from this system is correlated with AERONET sunphotometer data, and, when available, CALIPSO satellite data. In addition a trajectory model (HYSPLIT) is used to calculate backward trajectories to assess the origin of the dust polluted air parcels. The objective is to create a transport database of Saharan dust.
Application of a multiple scattering model to estimate optical depth, lidar ratio and ice crystal effective radius of cirrus clouds observed with lidar.
Authors: Gouveia Diego , Baars Holger , Seifert Patric , Wandinger Ulla , Barbosa Henrique , Barja Boris , Artaxo Paulo , Lopes Fabio , Landulfo Eduardo , Ansmann Albert
Published: April 2018

Lidar measurements of cirrus clouds are highly influenced by multiple scattering (MS). We therefore developed an iterative approach to correct elastic backscatter lidar signals for multiple scattering to obtain best estimates of single-scattering cloud optical depth and lidar ratio as well as of the ice crystal effective radius. The approach is based on the exploration of the effect of MS on the molecular backscatter signal returned from above cloud top.
Cirrus clouds properties derived from polarized micro pulse lidar (p-mpl) observations at the atmospheric observatory ‘el arenosillo’ (sw iberian peninsula): a case study for radiative implications
Authors: Águila Ana del , Gómez Laura , Vilaplana José Manuel , Sorribas Mar , Córdoba-Jabonero Carmen
Published: April 2018

Cirrus (Ci) clouds are involved in Climate Change concerns since they affect the radiative balance of the atmosphere. Recently, a polarized Micro Pulse Lidar (P-MPL), standard system within NASA/MPLNET has been deployed at the INTA/Atmospheric Observatory ‘El Arenosillo’ (ARN), located in the SW Iberian Peninsula. Hence, the INTA/P-MPL system is used for Ci detection over that station for the first time. Radiative effects of a Ci case observed over ARN are examined, as reference for future long-term Ci observations. Optical and macrophysical properties are retrieved, and used for radiative transfer simulations. Data are compared to the measured surface radiation levels and all-sky images simultaneously performed at the ARN station.
Wildfire smoke transport and impact on air quality observed by a mullti-wavelength elastic-raman lidar and ceilometer in New York city
Authors: Wu Yonghua , Peña Wilson , Gross Barry. , Moshary Fred
Published: April 2018

The intense wildfires from the western Canada in May 2016 injected large amount of smoke into the atmosphere. This paper presents integrated observation of the event by a lidar, ceilometer, and satellite together with models and an assessment of smoke plume impacts on local air quality in New York City (NYC) area. A dense aloft plume on May 20 and a boundary layer plume on May 25 are analyzed. The smoke mixing into planetary-boundary-layer (PBL) and strong diurnal variation of PBL-top are shown. For the 2ndcase, the ground PM2.5 measurements show a significant increase in both the urban and upwind non-urban areas of NYC. The smoke sources and transport paths are further verified by the satellite observations and HYSPLIT model data.