bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracking the Multistep Formation of Ln(III) Complexes with in situ Schiff Base Exchange Reaction and its Highly Selective Sensing of Dichloromethane
Authors: Mo Kai-Qiang , Ma Xiong-Feng , Wang Hai-Ling , Zhu Zhong-Hong , Liu Yan-Cheng , Zou Hua-Hong , Liang Fu-Pei
Published: August 2019

Four complexes, namely, [Ln2(L2)2(NO3)4]. 2CH3OH (Ln = Tb (1), Dy (2), Ho (3), Er (4), and L2 = (E)-2-methoxy-6-(((pyridin-2-ylmethyl)imino)methyl)phenol), were obtained by reacting (E)-2-((3-methoxy-2-oxidobenzylidene)amino)ethanesulfonate (L1), Ln(NO3)3·6H2O, and 2-aminomethylpyridine at room temperature under solvothermal conditions in methanol for 12 h. The new Schiff base L2 was generated in situ based on the organic ligand L1 and 2-aminomethylpyridine through Schiff base exchange reaction by using lanthanide salts as inductor. A combination of crystallography and mass spectrometry was performed to track the exchange reaction, and the underlying mechanism accompanied by the complex assembly process was clearly presented. The multistep formation mechanism of the above dinuclear complex was also proposed, i.e., [L1] → Dy[L1]/[L2] → Dy[L2] → Dy[L2]2 → Dy2[L2]2. Luminescence test of 1 showed that it had extremely high selectivity to dichloromethane (CH2Cl2). Therefore, we established a quick, simple, and efficient method of detecting CH2Cl2 that enabled strong-luminescence observation with the naked eye. Tests for small amounts of CH2Cl2 in water further indicated the potential of 1 as a test strip for CH2Cl2 fluorescence detection in water samples. Alternating-current magnetic susceptibility studies indicated the field-induced single-molecule magnet behavior of 2.
Sida hermaphrodita seeds as the source of anti - Candida albicans activity
Authors: Lewtak Kinga , Fiołka Marta J. , Czaplewska Paulina , Macur Katarzyna , Kaczyński Zbigniew , Buchwald Tomasz , Szczuka Ewa , Rzymowska Jolanta
Published: August 2019

Sida hermaphrodita is a perennial herbaceous plant with potential economic importance; however, there is no information about its antimicrobial properties. The aim of our study was to analyze the morphology and metabolic activity of Candida albicans cells after exposure to the extract from S. hermaphrodita seeds, determine its cytotoxicity against human skin fibroblasts and carry out chemical analysis of the extract. Microscopic analysis showed that the crude seed extract (CSE) caused a significant decrease in the metabolic activity of fungal cells, clear cell deformation, and budding disturbances. The analysis of cytotoxicity showed no influence of the extract on the fibroblasts. The CSE and seed extract after dialysis (DSE) were analyzed using electrophoretic, chromatographic, and spectroscopic methods. SDS-PAGE electrophoresis showed the presence of proteins and carbohydrate compounds in the extract. The Raman spectroscopy analysis of the DSE confirmed the presence of proteins, while FTIR analyses revealed the occurrence of albumin-type proteins. The NMR and GC-MS analyses showed the presence of carbohydrates in the seed extract. The MALDI and ESI LC-MS/MS analysis of the CSE and the DSE fractions revealed the occurrence of vicilin-type and plant lipid transfer proteins. The seed extract is a promising formulation to use in C. albicans infections.
Far-ranging generalist top predators enhance the stability of meta-foodwebs
Authors: Brechtel Andreas , Gross Thilo , Drossel Barbara
Published: August 2019

Identifying stabilizing factors in foodwebs is a long standing challenge with wide implications for community ecology and conservation. Here, we investigate the stability of spatially resolved meta-foodwebs with far-ranging super-predators for whom the whole meta-foodwebs appears to be a single habitat. By using a combination of generalized modeling with a master stability function approach, we are able to efficiently explore the asymptotic stability of large classes of realistic many-patch meta-foodwebs. We show that meta-foodwebs with far-ranging top predators are more stable than those with localized top predators. Moreover, adding far-ranging generalist top predators to a system can have a net stabilizing effect. These results highlight the importance of top predator conservation.
Yields and resilience outcomes of organic, cover crop, and conventional practices in a Mediterranean climate
Authors: Li Meng , Peterson Caitlin A. , Tautges Nicole E. , Scow Kate M. , Gaudin Amélie C. M.
Published: August 2019

Adaptive management practices that maximize yields while improving yield resilience are required in the face of resource variability and climate change. Ecological intensification such as organic farming and cover cropping are lauded in some studies for fostering yield resilience, but subject to criticism in others for their low productivity. We implemented a quantitative framework to assess yield resilience, emphasizing four aspects of yield dynamics: yield, yield stability, yield resistance (i.e., the ability of systems to avoid crop failure under stressful growing conditions), and maximum yield potential. We compared the resilience of maize-tomato rotation systems after 24 years of irrigated organic, cover cropped, and conventional management in a Mediterranean climate, and identified crop-specific resilience responses of tomato and maize to three management systems. Organic management maintained tomato yields comparable to those under conventional management, while increasing yield stability and resistance. However, organic and cover cropped system resulted in 36.1% and 35.8% lower maize yields and reduced yield stability and resistance than the conventional system. Our analyses suggest that investments in ecological intensification approaches could potentially contribute to long-term yield resilience, however, these approaches need to be tailored for individual crops and systems to maximize their benefits, rather than employing one-size-fits-all approaches.
Highly-efficient laser ablation of copper by bursts of ultrashort tuneable (fs-ps) pulses
Authors: Žemaitis Andrius , Gečys Paulius , Barkauskas Martynas , Račiukaitis Gediminas , Gedvilas Mindaugas
Published: August 2019

Ultrashort pulse laser, capable of varying pulse duration between 210 fs and 10 ps and producing a burst of pulses with an intra-burst pulse repetition rate of 64.5 MHz (time distance between pulses 15.5 ns), was used to investigate the ablation efficiency of the copper. The study on ablation efficiency was done for various numbers of pulses per burst between 1 and 40. The increase in the ablation efficiency by 20% for 3 pulses per burst compared to a non-burst regime was observed. The comparison was made between the beam-size optimised regimes. Therefore, the real advantage of the burst regime was demonstrated. To the best of our knowledge, we report the highest laser milling ablation efficiency of copper of 4.84 µm3/µJ by ultrashort pulses at ~1 µm optical wavelength.
Incidence and Neonatal Risk factors of Short Stature and Growth Hormone treatment in Japanese Preterm Infants Born Small for Gestational Age
Authors: Matsumoto Masaaki , Nagano Nobuhiko , Awano Hiroyuki , Ohyama Shohei , Fujioka Kazumichi , Iwatani Sota , Urakami Tatsuhiko , Iijima Kazumoto , Morioka Ichiro
Published: August 2019

Incidence and neonatal risk factors for short stature in preterm children born small for gestational age (SGA) have not been fully investigated in Japan. In this prospective study, infants born ≤32 weeks’ gestational age (GA) from 2004–2015 were enrolled and followed for 3 years. Incidence of short children born SGA and short stature treated with growth hormone (GH) were investigated. Neonatal risk factors were analysed using univariate and multivariate analyses. GA cut-off value was determined using receiver operating characteristic (ROC) curve analyses. Of 604 infants born ≤32 weeks’ GA, 76 (13%) were SGA at birth. Twenty-seven infants (36%) developed short stature at age 2 and 14 infants (19%) received GH treatment at age 3. GA, birthweight, birth length, birth head circumference, and chronic lung disease at 36 weeks’ corrected GA were determined as risk factors by univariate analyses (p < 0.01). Multivariate analyses only revealed low GA as an independent risk factor. ROC curve analysis determined a cut-off value of 24 weeks’ GA. Nineteen percent of preterm SGA infants ≤32 weeks’ GA developed short stature treated with GH. A low GA at birth could be an early detection marker for short stature that requires GH treatment in preterm infants born SGA.
Properties of echoic memory revealed by auditory-evoked magnetic fields
Authors: Kinukawa Tomoaki , Takeuchi Nobuyuki , Sugiyama Shunsuke , Nishihara Makoto , Nishiwaki Kimitoshi , Inui Koji
Published: August 2019

We used auditory-evoked magnetic fields to investigate the properties of echoic memory. The sound stimulus was a repeated 1-ms click at 100 Hz for 500 ms, presented every 800 ms. The phase of the sound was shifted by inserting an interaural time delay of 0.49 ms to each side. Therefore, there were two sounds, lateralized to the left and right. According to the preceding sound, each sound was labeled as D (preceded by a different sound) or S (by the same sound). The D sounds were further grouped into 1D, 2D, and 3D, according to the number of preceding different sounds. The S sounds were similarly grouped to 1S and 2S. The results showed that the preceding event significantly affected the amplitude of the cortical response; although there was no difference between 1S and 2S, the amplitudes for D sounds were greater than those for S sounds. Most importantly, there was a significant amplitude difference between 1S and 1D. These results suggested that sensory memory was formed by a single sound, and was immediately replaced by new information. The constantly-updating nature of sensory memory is considered to enable it to act as a real-time monitor for new information.
Validation of HPLC and UHPLC methods for the simultaneous quantification of ferulic acid and nicotinamide in the presence of their degradation products
Authors: Chaves Júnior José Venâncio , dos Santos Jonh Anderson Borges , Ferreira George Leandro Ramos , Porto Dayanne Lopes , Oliveira Artur de Santana , Nogueira Fernando Henrique Andrade , de Souza Fábio Santos , Aragão Cícero Flávio Soares
Published: August 2019

Two analytical methods, by HPLC and UHPLC, were validated and applied in the quantification of ferulic acid and nicotinamide in the presence of their photo and basic degradation products, cis-ferulic acid and nicotinic acid, respectively.
Externally driven molecular ratchets on a periodic potential surface: a rate equations approach
Authors: Sang Hongqian , Abbasi-Pérez David , Recio José Manuel , Kantorovich Lev
Published: August 2019

The long time dynamics of molecular ratchets on a 1D periodic potential energy surface (PES) subjected to an external stimulus is studied using the rate equation method.
Morphologies of a polyelectrolyte brush grafted onto a cubic colloid in the presence of trivalent ions
Authors: Tan Hong-Ge , Xia Gang , Liu Li-Xiang , Miao Bing
Published: August 2019

Electrostatic correlation induces the non-monotonic variation of the brush height, multi-scale ordering and abundant lateral separated patterns.
Understanding trends in methane oxidation to formaldehyde: statistical analysis of literature data and based hereon experiments
Authors: Fait M. J. G. , Ricci A. , Holena M. , Rabeah J. , Pohl M.-M. , Linke D. , Kondratenko E. V.
Published: August 2019

A regression tree analysis on selective oxidation of methane to methanol/formaldehyde was applied to identify fundamentals affecting catalyst performance. The electronegativity correlates with methane activation energy and formaldehyde selectivity.
Electrochemical tuning of heterojunctions in TiO2 nanotubes for efficient solar water splitting
Authors: Preethi L. K. , Mathews Tom
Published: August 2019

The electrochemical assisted biphase ↔ triphase switching in TiO2 nanotubes and their comprehensive photocatalytic hydrogen generation efficiencies are presented.
Exploration of catecholase-like activity of a series of magnetically coupled transition metal complexes of Mn, Co and Ni: new insights into the solution state behavior of Mn complexes
Authors: Sarkar Abani , Chakraborty Aratrika , Adhikary Amit , Maity Suvendu , Mandal Arnab , Samanta Debabrata , Ghosh Prasanta , Das Debasis
Published: August 2019

Oxidation state dependent catecholase activity has been explored with Mn-Schiff-base complex which transform oxidation state from +ii to +iii in solution with time by combined experimental and theoretical investigations.
Water soluble, optically active monofunctional Pd(ii) and Pt(ii) compounds: promising adhesive and antimigratory effects on human prostate PC-3 cancer cells
Authors: de la Cueva-Alique Isabel , Muñoz-Moreno Laura , de la Torre-Rubio Elena , Bajo Ana M. , Gude Lourdes , Cuenca Tomás , Royo Eva
Published: August 2019

Water soluble, enantiomerically pure “rule breakers” Pd(ii) and Pt(ii) compounds with promising anticancer potential are reported.
A new diphosphate Ba2LiGa(P2O7)2: synthesis, crystal structure and Eu3+-activated fluorescence performance
Authors: Li Y. N. , Zhao D. , Zhang R. J. , Li F. F. , Shi L. Y. , Yao Q. X. , Han X. Y. , Cui X. Q.
Published: August 2019

This work presents a new diphosphate Ba2LiGa(P2O7)2with an anionic [LiGa(P2O7)2]∞framework that is constructed from P2O7, LiO5and GaO6groups. Eu3+-doped Ba2−xLiGa(P2O7)2:xEu3+(x= 0.05–0.3) samples show intense red photoluminescence emission.
Analysis of the antimicrobial activity ofLactobacillus plantarumYM-4-3: implications of suitable conditions for extending the shelf life of fermented soybean products
Authors: Liu Chen-Jian , Luo Ming-Yue , Li Qiang-Kun , Deng Gang , Li Xiao-Ran , Yang En , Luo Yi-Yong
Published: August 2019

The shelf life of fermented soybean products is extended following combination treatment withLactobacillus plantarumand low concentration sodium chloride.
Sustainable valorization of lignin with levulinic acid and its application in polyimine thermosets
Authors: Huang Kaifeng , Ma Songqi , Wang Sheng , Li Qiong , Wu Zhijun , Liu Jingcheng , Liu Ren , Zhu Jin
Published: August 2019

Valorization of lignin with renewable levulinic acid incorporated active ketone groups and could be utilized to produce high-performance polymers.
Catalytic asymmetric synthesis of chiral phenols in ethanol with recyclable rhodium catalyst
Authors: Yao Jian , Liu Na , Yin Long , Xing Junhao , Lu Tao , Dou Xiaowei
Published: August 2019

A general method to access diverse chiral phenols in ethanol using a recyclable catalyst was developed.
A Raman, SERS and UV-circular dichroism spectroscopic study of N-acetyl-l-cysteine in aqueous solutions
Authors: Picot R. A. Cobos , Puiatti M. , Ben Altabef A. , Rubira R. J. G. , Sanchez-Cortes S. , Diaz S. B. , Tuttolomondo M. E.
Published: August 2019

The aim of this work is to evaluate the vibrational and structural properties of N-acetyl-l-cysteine (NAC), and its molecular structure and electronic properties in relation to the action of thiol and amine groups at different pH.
Active control of graphene-based membrane-type acoustic metamaterials using a low voltage
Authors: Li Ying , Wang Shasha , Peng Qingyu , Zhou Zhenwei , Yang Zhiyu , He Xiaodong , Li Yibin
Published: August 2019

Membrane-type acoustic metamaterials for acoustic insulation applications have been attracting ever increasing attention.
Biphasic signals during nanopore translocation of DNA and nanoparticles due to strong ion cloud deformation
Authors: Sensale Sebastian , Peng Zhangli , Chang Hsueh-Chia
Published: August 2019

We report a theory for biphasic ionic current signals during DNA and nanoparticle translocation through a solid-state nanopore that produces scaling results consistent with continuum simulations, molecular dynamics simulations, and experiments.
Strategy to boost catalytic activity of polymeric carbon nitride: synergistic effect of controllable in situ surface engineering and morphology
Authors: Li Yuan-Yuan , Si Yuan , Zhou Bing-Xin , Huang Wei-Qing , Hu Wangyu , Pan Anlian , Fan Xiaoxing , Huang Gui-Fang
Published: August 2019

The controllable introduction of hydroxyl groups on CN nanoshells leads to spatial separation of the HOMO and LUMO, and effective exciton dissociation.
One-pot synthesis of hollow PDA@DOX nanoparticles for ultrasound imaging and chemo-thermal therapy in breast cancer
Authors: Zhang Tao , Jiang Zhenqi , Xve Ting , Sun Shan , Li Juan , Ren Wenzhi , Wu Aiguo , Huang Pintong
Published: August 2019

A one-pot synthesis of hollow nanoparticles (PDA@DOX) used for breast cancer treatment with an extremely high drug loading rate and dual stimuli-responsive drug delivery capacity. PDA@DOX demonstrated good photothermal performance and ultrasound imaging capability.
An AIE molecule featuring changeable triplet emission between phosphorescence and delayed fluorescence by an external force
Authors: Huang Lili , Wen Xue , Liu Jianwei , Chen Mingxing , Ma Zhiyong , Jia Xinru
Published: August 2019

A newly designed molecule ODFRPTZ with asymmetric D–A–D′ type structure is endowed with aggregation-induced emission (AIE), intriguing mechanochromism and changeable emission between delayed fluorescence and phosphorescence by external force.
Micro-mechanical properties of a novel silicon nitride fiber reinforced silicon carbide matrix compositevia in situnano-indentation method
Authors: Sun Xun , Jiang Ru , Liu Haitao , Cheng Haifeng
Published: August 2019

A novel Si3N4fiber reinforced SiC matrix composite has been prepared and the micro-mechanical properties of the compositesin situhave been explored.
Designing triazatruxene-based donor materials with promising photovoltaic parameters for organic solar cells
Authors: Khan Muhammad Usman , Iqbal Javed , Khalid Muhammad , Hussain Riaz , Braga Ataualpa Albert Carmo , Hussain Munawar , Muhammad Shabbir
Published: August 2019

Five new molecules (M1–M5) were designed by structural modification of acceptor moiety (rhodanine-3-acetic acid) of well-known synthesized dye JY05, and their optoelectronic properties are evaluated to be used as donor molecules in organic solar cells.
Applications and potential mechanisms of herbal medicines for rheumatoid arthritis treatment: a systematic review
Authors: Li Tai-ping , Zhang Ai-hua , Miao Jian-hua , Sun Hui , Yan Guang-li , Wu Fang-fang , Wang Xi-jun
Published: August 2019

In this review, we systematically discuss the role of traditional Chinese medicine (TCM) in rheumatoid arthritis (RA) disease treatment.
A red-emitting Sr3La(1−x)Eux(AlO)3(BO3)4 phosphor with high thermal stability and color purity for near-UV-excited wLEDs
Authors: Yue Cheng , Zhu Dachuan , Yan Qun , Pu Yong
Published: August 2019

The red-emitting Sr3La(1−x)Eux(AlO)3(BO3)4 phosphor with high thermal stability and color purity (92.4%) is synthesized for white LEDs.
Theoretical screening of bistriazole-derived energetic salts with high energetic properties and low sensitivity
Authors: Li Xiao-Hong , Zhang Cong , Ju Xue-Hai
Published: August 2019

We designed four series of energetic anions by replacing nitro group (NO2) with trinitromethyl group (C(NO2)3) or by inserting N-bridging groups (–NH–, –NH–NH–, –NN–, –NN(O)–) into the bistriazole frameworks.
Hidden symmetry of the anomalous bluetongue virus capsid and its role in the infection process
Authors: Konevtsova Olga V. , Roshal Daria S. , Lošdorfer Božič Anže , Podgornik Rudolf , Rochal Sergey
Published: August 2019

The simple structural model and electrostatic mechanism proposed explain the trimer detachment from the surface of the bluetongue capsid.
A sequential condensation route as a versatile platform for low cost and efficient hole transport materials in perovskite solar cells
Authors: Pashaei Babak , Shahroosvand Hashem , Ameri Mohsen , Mohajerani Ezeddin , Nazeeruddin Mohammad Khaja
Published: August 2019

In an effort to diminish the cost of perovskite solar cells (PSCs) with regard to hole transport materials (HTMs), we employed an easily attainable condensation route to synthesize a cheap and efficient HTM.
2D molecular crystal lattices: advances in their synthesis, characterization, and application
Authors: Solomos Marina A. , Claire F. James , Kempa Thomas J.
Published: August 2019

2D molecular crystal lattices form a compelling class of 2D materials with synthetically-tunable properties and the potential to spawn a new generation of devices for optoelectronics and energy sustainability.
A functional SrF2 coated separator enabling a robust and dendrite-free solid electrolyte interphase on a lithium metal anode
Authors: Li Xing , Liu Yang , Pan Yong , Wang Mingshan , Chen Junchen , Xu Hao , Huang Yun , Lau Woon Ming , Shan Aixian , Zheng Jianming , Mitlin David
Published: August 2019

An SrF2 microsphere layer on a separator could be involved in SEI formation and result in a dendrite free SEI on a lithium anode.
A new P2-type layered oxide cathode with superior full-cell performances for K-ion batteries
Authors: Hwang Jang-Yeon , Kim Jongsoon , Yu Tae-Yeon , Jung Hun-Gi , Kim JaeKook , Kim Kwang-Ho , Sun Yang-Kook
Published: August 2019

The P2-type K0.75[Fe0.1Ni0.1Mn0.8]O2 cathode synthesized via an electrochemical ion exchange method has a highly stable layered oxide framework, demonstrating its outstanding power capability as well as long-term cycling stability.
Co–Mn spinel supported self-catalysis induced N-doped carbon nanotubes with high efficiency electron transport channels for zinc–air batteries
Authors: Su Hang , Wang Xiao-Tong , Hu Jing-Xiao , Ouyang Ting , Xiao Kang , Liu Zhao-Qing
Published: August 2019

The optimized CoMn2O4/NCNTs@Ni with high valence Mn3.4+ as the catalytic site center, combined with the spinel-NCNTs-Ni electron transport channels jointly promote the electrocatalytic activity and successfully applied in zinc–air battery.
Self-healing conductive hydrogels based on alginate, gelatin and polypyrrole serve as a repairable circuit and a mechanical sensor
Authors: Ren Kai , Cheng Yu , Huang Chao , Chen Rui , Wang Zhao , Wei Jie
Published: August 2019

Polypyrrole/alginate–gelatin conductive hydrogels serve as a repairable circuit and a mechanical sensor.
Enhancing the intermolecular singlet fission efficiency by controlling the self-assembly of amphipathic tetracene derivatives in aqueous solution
Authors: Tang Zhaofeng , Zhou Sainan , Wang Xiangyang , Liu Heyuan , Yan Xinyu , Liu Shanshan , Lu Xiaoqing , Li Xiyou
Published: August 2019

Introduction of the carboxyl group onto tetracene can change the singlet fission mechanism and increase the singlet fission yield in its nanoparticles.
Multimodal control of liquid crystalline mesophases from surfactants with photoswitchable tails
Authors: Houston Judith E. , Kelly Elaine A. , Kruteva Margarita , Chrissopoulou Kiriaki , Cowieson Nathan , Evans Rachel C.
Published: August 2019

Azobenzene surfactants transform into a rich variety of single-component liquid crystalline mesophases through strategic control of molecular design, concentration, temperature and light, paving the way to new photoresponsive materials.
Effect of Negative Middle Ear Pressure and Compensated Pressure on Wideband Absorbance and Otoacoustic Emissions in Children
Authors: Aithal Sreedevi , Aithal Venkatesh , Kei Joseph , Manuel Alehandrea
Published: August 2019

Objective

This study investigated pressurized transient evoked otoacoustic emission (TEOAE) responses and wideband absorbance (WBA) in healthy ears and ears with negative middle ear pressure (NMEP).

Method

In this cross-sectional study, TEOAE amplitude, signal-to-noise ratio, and WBA were measured at ambient and tympanometric peak pressure (TPP) in 36 ears from 25 subjects with healthy ears (age range: 3.1–13.0 years) and 88 ears from 76 patients with NMEP (age range: 2.0–13.1 years), divided into 3 groups based on NMEP (Group 1 with TPP between −101 and −200 daPa, Group 2 with TPP between −201 and −300 daPa, and Group 3 with TPP between −301 and −400 daPa).

Results

Mean TEOAE amplitude, signal-to-noise ratio, and WBA were increased at TPP relative to that measured at ambient pressure between 0.8 and 1.5 kHz. Further decrease in TPP beyond −300 daPa did not result in further increases in the mean TEOAE or WBA at TPP. The correlation between TEOAE and WBA was dependent on the frequency, pressure conditions, and subject group. There was no difference in pass rates between the 2 pressure conditions for the control group, while the 3 NMEP groups demonstrated an improvement in pass rates at TPP. With pressurization, the false alarm rate for TEOAE due to NMEP was reduced by 17.8% for NMEP Group 1, 29.2% for NMEP Group 2, and 15.8% for NMEP Group 3.

Conclusion

Results demonstrated the feasibility and clinical benefits of measuring TEOAE and WBA under pressurized conditions. Pressurized TEOAE and WBA should be used for assessment of ears with NMEP in hearing screening programs to reduce false alarm rates.
The Influence of Native- Versus Foreign-Accented Speech on Spanish–English Bilingual Children's Spanish Receptive Vocabulary Performance: A Pilot Study
Authors: Gibson Todd A.
Published: August 2019

Purpose

There are many fewer speech-language pathologists (SLPs) who can administer Spanish language testing than there are children in the United States who need such testing. Although there are precautions against language testing by foreign speakers, results from testers using native- versus foreign-accented speech have not been compared using popular picture-pointing vocabulary tests of the sort used by SLPs. Therefore, we sought to determine if nonnative Spanish speech (i.e., foreign-accented speech) was sufficient for the administration of a Spanish receptive vocabulary test.

Method

Using a single group, within-subjects design, 15 Spanish–English bilingual 5-year-olds from a low socioeconomic background listened to native- and foreign-accented digital audio recordings of targeted vocabulary words. Native- and foreign-accented testing was counterbalanced with a 2-month interlude. Using standard procedures, children were also administered English and Spanish–English bilingual picture-pointing vocabulary tests. Language histories were collected from caregivers and teachers.

Results

Standard scores were significantly lower for foreign- than for native-accented Spanish vocabulary testing. However, native-accented testing produced outcomes similar to those found in the literature for standard administration procedures.

Conclusions

Results support precautions that language testers should be proficient in the language of testing. However, standardized picture-pointing receptive vocabulary tests might be amenable to adaptations using recorded speech instead of standard procedures. This potentially extends the number of SLPs who might administer some Spanish testing.
Fully distributed consensus for general linear multi‐agent systems with unknown external disturbances
Authors: Huo Yanwei , Lv Yuezu , Wu Xiang , Duan Zhisheng
Published: August 2019

This study investigates the consensus problem for general linear multi‐agent systems with unknown external disturbances. Both the leaderless and the leader–follower consensus problems are considered. By using the absolute output information of each agent, the local states and external disturbances of each agent can be estimated by an extended state observer. Then, by using the relative estimated states and disturbance estimation, the continuous controller can be designed in a fully distributed fashion, which ensures that the consensus error of general linear multi‐agent systems converges to zero eventually with the complete disturbance rejection. Moreover, when the absolute output information of each agent is not available, it is shown that the consensus problem can be solved by using only relative output information of neighbouring agents but only the part of the disturbances that affect the common trajectories will be rejected. Finally, simulation examples are given to demonstrate the effectiveness of the proposed protocols. Compared with the previous related works, fully distributed consensus disturbance rejection protocols are developed based on node‐based adaptive design and edge‐based adaptive design, which require neither global information of the communication graph nor the prior knowledge of the disturbance model.
Day‐ahead energy management framework for a networked gas–heat–electricity microgrid
Authors: Reza Massrur Hamid , Niknam Taher , Fotuhi‐Firuzabad Mahmud
Published: August 2019

The integration of various energy supplying systems increases the energy efficiency and energy system reliability. Smart microgrids are an ideal area to use multi‐carrier energy systems. In this context, this study presents a novel modelling framework for optimal day‐ahead scheduling of a networked multi‐carrier energy microgrid (NMCEMG) system. The NMCEMG system in this study is composed of heat, gas, and power supply networks. The presented framework has enhanced the multi‐carrier microgrid modelling against the previous works that modelled the multi‐carrier microgrid as an energy hub due to difficulties in the energy flow analysis of heat and gas networks. The proposed framework optimises the day‐ahead operating cost of the NMCEMG system considering nodal and energy flow constraints of each network. The proposed microgrid includes various energy interdependent equipment such as combined heat and power units, gas‐fired boilers, power to gas units, electrical and heat storages and electric heat pumps. This study presents a new optimisation algorithm named self‐adaptive modified whale optimisation algorithm based on wavelet theory to solve the day‐ahead optimal scheduling of the NMCEMG problem. The numerical results corroborate the proposed modelling framework as superior over conventional hub‐based multi‐carrier microgrid models in terms of energy system security.
Perspectives on stability and mobility of transit passenger's travel behaviour through smart card data
Authors: Cui Zhiyong , Long Ying
Published: August 2019

Existing studies have extensively used spatiotemporal data to discover the mobility patterns of various types of travellers. Smart card data (SCD) collected by the automated fare collection systems can reflect a general view of the mobility pattern of public transit riders. Mobility patterns of transit riders are temporally and spatially dynamic, and therefore difficult to measure. However, few existing studies measure both the mobility and stability of transit riders’ travel patterns over a long period of time. To analyse the long‐term changes of transit riders’ travel behaviour, the authors define a metric for measuring the similarity between SCD, in this study. Also an improved density‐based clustering algorithm, simplified smoothed ordering points to identify the clustering structure (SS‐OPTICS), to identify transit rider clusters is proposed. Compared to the original OPTICS, SS‐OPTICS needs fewer parameters and has better generalisation ability. Further, the generated clusters are categorised according to their features of regularity and occasionality. Based on the generated clusters and categories, fine‐ and coarse‐grained travel pattern transitions of transit riders over four years from 2010 to 2014 are measured. By combining socioeconomic data of Beijing in the year of 2010 and 2014, the interdependence between stability and mobility of transit riders’ travel behaviour is also discussed.
Model predictive current control based on a generalised adjacent voltage vectors approach for multilevel inverters
Authors: Ipoum‐Ngome Paul Gistain , Mon‐Nzongo Daniel Legrand , Flesch Rodolfo C.C. , Song‐Manguelle Joseph , Wang Mengqi , Jin Tao
Published: August 2019

Model predictive current control (MPCC) uses the discrete‐time model of a system to predict the future behaviour of the current for all voltage vectors (VVs) generated by a power converter. In multilevel inverters, the large number of VVs imposes a long computation time for the prediction and selection of the optimal state to be applied to the converter, which increases the sampling time and decreases the closed‐loop performance. An MPCC is proposed based on the idea of generalised adjacent voltage vectors (GAVVs) for multilevel cascaded H‐bridge inverters with a DC‐link voltage fed by photovoltaic (PV) cells. This method deals with the voltage drop and often small inter‐bridge voltage imbalance and irradiance issues that occur in PV power plants. The proposed GAVV method is analytically formulated to provide three types of subsets for a given number of inverter levels. The use of the newly added subsets of four and five VVs contributes to boosting the converter output voltage and achieving acceptably balanced current and line‐to‐line voltage under low irradiance compared with the classical approach. Simulation and experimental results show good current response and reduced switching frequency even under a high current reference with DC‐link voltage drop.
Dual‐loop control of transfer delay based PLL for fast dynamics in single‐phase AC power systems
Authors: Gautam Samir , Lu Yuezhu , Xiao Weidong , Lu Dylan Dah‐Chuan , Golsorkhi Mohammad S.
Published: August 2019

Phase‐locked loop (PLL) is commonly utilised for AC power systems to detect phase and frequency. With the increasing use of small‐scale distributed power generation, the technique becomes widely available for grid interconnection of renewable power source into single‐phase AC distribution network. Through comprehensive analysis and design, this study proposed a new approach that includes dual independent control loops to enhance the transfer delay‐based PLL capability in terms of speed and accuracy. The effectiveness and advantages of the proposed PLL structure are demonstrated by numerical simulation and verified by experimental test.
Control strategy for suppression of circulating current using high‐frequency voltage compensation in asynchronous carriers for modular and scalable inverter systems
Authors: Kang Shin‐Won , Choi Seung‐Yeon , Im Jun‐Hyuk , Kim Rae‐Young , Kim Sang‐Il
Published: August 2019

In this study, a circulating current suppression strategy is proposed using high‐frequency voltage compensation when asynchronous carriers exist between modules in modular and scalable inverter systems (MSISs). In MSIS, an inverter and a control unit constitute one module. Because each module is connected in parallel, the power capacity and efficiency can be increased. However, according to the switching state in the parallel module, a circulating current can be generated. This current causes stress on the switches. Furthermore, the circulating current not only deteriorates the current control performance but also increases the difficulty of load sharing. In this study, a novel method is proposed to suppress high‐frequency circulating current caused by asynchronous carriers. This current can be reduced by generating the same switching pattern in two modules using high‐frequency voltage compensation. Simulation and experimental results are presented to verify the proposed method.
All SiC PWM rectifier‐based off‐board ultrafast charger for heavy electric vehicles
Authors: Yildirim Doğan , Öztürk Serkan , Çadirci Işık , Ermiş Muammer
Published: August 2019

This study deals with the design, implementation and experimental performance of all silicon carbide pulse width modulation (SiC PWM) rectifier‐based off‐board ultrafast chargers (UFCs) for lithium titanate batteries of heavy electric vehicles. Different UFC configurations are proposed, depending upon the nominal battery voltage (400–1000 V DC) and charge capacity. Operating principles and control of UFC at unity and leading power factors are assessed and corresponding operating modes of PWM rectifier are discussed. The combined effect of reverse conduction characteristic of SiC power metal oxide semiconductor field effect transistor (MOSFET) and built‐in SiC Schottky diode is taken into account in all the analyses carried out. The operating performance of the developed UFC, such as the switching characteristics of SiC power MOSFET modules, efficiency, input current total demand distortion (ITDD), and thermal limitations of the SiC PWM rectifier have been assessed for various charge voltages and charge capacities, both by computer simulations and laboratory tests. Power circuit layout considerations of the proposed system are also given in this study. Excellent performance results for 10 kHz switching frequency are obtained from the developed 200 kW UFC, with operating efficiencies higher than 98.5% for all charging rates up to five times the battery capacity, and ITDDs <2.2% for the whole operating range.
Effect of gamma irradiation on space charge and charge trap characteristics of epoxy–MgO nanocomposites
Authors: Guvvala Nagaraju , Nageshwar Rao Burjupati , Sarathi Ramanujam
Published: August 2019

Insulating materials used in power apparatus required to be space charge free. Epoxy–magnesium oxide (MgO) nanocomposites were prepared and gamma rays were irradiated for different dosages to understand the dielectric parameters variation, space charge characteristics, surface potential variations, and for getting charge trap characteristics of the material. It is realised that permittivity increases and then reduces when the irradiation level is increased. Tan (δ) marginally increased with increasing dosage of gamma irradiation. Space charge accumulation reduces with increase in wt% of MgO in epoxy resin. 3 and 5 wt% MgO added samples showed stable space charge accumulation and fast decay during depoling, irrespective of irradiation level. Surface potential decay time reduces with irradiated specimens. After irradiation, epoxy nanocomposites showed both shallow trap formation and deep trap formation and found that shallow trap density is high compared to the deep trap density. All the irradiated specimens showed a decrease in the trap energy level compared to the virgin specimens.
Exploring the multiphase medium in MKW 08: from the central active galaxy up to cluster scales
Authors: Tümer A. , Tombesi F. , Bourdin H. , Ercan E. N. , Gaspari M. , Serafinelli R.
Published: August 2019

Context. The study of the brightest cluster galaxy (BCG) coronae embedded in noncool core (NCC) galaxy clusters is crucial to understand the BCG’s role in galaxy cluster evolution as well as the activation of the self-regulated cooling and heating mechanism in the central regions of galaxy clusters.

Aims. We explore the X-ray properties of the intracluster medium (ICM) of the NCC galaxy cluster MKW 08 and the BCG corona, along with their interface region. With recent and deep archival Chandra observations, we study the BCG corona in detail, and with archival XMM-Newton observations, we investigate the implications of the central active galactic nuclei (AGN) on the BCG.

Methods. We carry out imaging and spectral analyses of MKW 08 with archival XMM-Newton and Chandra X-ray observations.

Results. Our spectral analysis suggests the presence of a central AGN by a power-law with a photon index of Γ ≃ 1.8 at the core of its BCG. Although the ICM does not exhibit a cluster scale cool core, the BCG manifests itself as a mini cool core characterized by a cooling time as short as 64 Myr at r = 3 kpc centered at the galaxy. The isothermality of the BCG corona seems to favor mechanical feedback from the central AGN as the major source of gas heating. The gas pressure profile of this mini cool core suggests that the BCG coronal gas reaches pressure equilibrium with the hotter and less dense ICM inside an interface of nearly constant pressure, delimited by radii 4 ≤ r ≤ 10 kpc at the galactic center. As revealed by the presence of a metal enriched tail (Z ≃ 0.5–0.9 Z⊙) extending up to 40 kpc, the BCG corona seems to be experiencing ram-pressure stripping by the surrounding ICM and/or interacting with a nearby galaxy, IC 1042.
Exploring helical dynamos with machine learning: Regularized linear regression outperforms ensemble methods
Authors: Nauman Farrukh , Nättilä Joonas
Published: August 2019

We use ensemble machine learning algorithms to study the evolution of magnetic fields in magnetohydrodynamic (MHD) turbulence that is helically forced. We perform direct numerical simulations of helically forced turbulence using mean field formalism, with electromotive force (EMF) modeled both as a linear and non-linear function of the mean magnetic field and current density. The form of the EMF is determined using regularized linear regression and random forests. We also compare various analytical models to the data using Bayesian inference with Markov chain Monte Carlo (MCMC) sampling. Our results demonstrate that linear regression is largely successful at predicting the EMF and the use of more sophisticated algorithms (random forests, MCMC) do not lead to significant improvement in the fits. We conclude that the data we are looking at is effectively low dimensional and essentially linear. Finally, to encourage further exploration by the community, we provide all of our simulation data and analysis scripts as open source IPYTHONnotebooks.
Chemical evolution of elliptical galaxies with a variable IMF
Authors: Yan Zhiqiang , Jerabkova Tereza , Kroupa Pavel , Vazdekis Alejandro
Published: August 2019

Growing evidence in recent years suggests a systematic variation of the stellar initial mass function (IMF), being top-heavy for starburst galaxies and possibly bottom-heavy for massive ellipticals. Galaxy chemical evolution simulations adopting an invariant canonical IMF face difficulty in simultaneously reproducing the metallicity and α-enhancement of the massive elliptical galaxies. Applying a variable IMF that changes with time is a promising solution, however, it is non-trivial to couple a variable IMF theory with the existing galaxy evolution codes. Here we present the first open source simulation code which recalculates the galaxy-wide IMF at each time step according to the integrated galactic IMF (IGIMF) theory where the galaxy-wide IMF depends on the galactic star formation rate and metallicity. The resulting galaxy-wide IMF and metal abundance evolve with time. With this pilot work, we explore the effect of the IGIMF theory on galaxy chemical evolution in comparison with an invariant IMF.
Heat recovery from Combined Cycle Power Plants for Heat Pumps
Authors: Vannoni Alberto , Sorce Alessandro , Bosser Sven , Buddenberg Torsten
Published: August 2019

Fossil fuel power plants, as combined cycle plants (CCGT), will increasingly have to shift their role from providing base-load power to providing fluctuating back-up power to control and stabilize the grid, but they also have to be able to run at the highest possible efficiency. Combined Heat and Power generation could be a smart solution to overcome the flexibility required to a modern power plant, this work investigates different layout possibilities allowing to increase the overall efficiency through the heat recover from the hot flue gasses after the heat recovery steam generator (HRSG) of a CCGT. The flue gas (FG) cooling aims to recover not only the sensible heat but also the latent heat by condensing the water content. One possible solution couples a heat pump to the flue gas condenser in order to increase the temperature at which the recovered heat is supplied, moreover the evaluated layout has to comply with the requirement of a minimum temperature before entering the stack.
A design tool for the performances comparison of innovative energy systems for naval applications
Authors: Rattazzi D. , Rivarolo M. , Lamberti T. , Magistri L.
Published: August 2019

This paper aims to develop a tool for the performances comparison of innovative energy systems on board ships, both for concentrated and distributed generation applications. In the first part of the study, the tool database has been developed throughout a wide analysis of the available market solutions in terms of energy generation devices (i.e. fuel cells, internal combustion engines, micro gas turbines), fuels (hydrogen, natural gas, diesel) and related storage technologies. Many of these data have been collected also thanks to the laboratory experience of the authors’ research group on different innovative energy systems. From the database, a wide range of maps has been created, correlating costs, volumes, weights and emissions with the installed power and the operational hours required, given by the user as input. The tool highlights the best solution according to the different relevance chosen by the user for each key parameter (i.e. costs, volumes, emissions). In the second part, two different case studies are presented in order to underline how the installed power, the different ship typology and the user requirements affect the choice of the best solution. It is worth noting that the methodology has a general value, as the tool can be applied to both the design of new ships, and to the retrofit of already existing ships in order to respect new requirements (e.g. more and more stringent normative in terms of pollutant emissions in ports and restricted areas). Furthermore, the database can be easily extended to other generation and storage technologies.
Design and development of a laboratory for the study of PEMFC system for marine applications
Authors: Borgogna Gerardo , Speranza Enrico , Lamberti Thomas , Nicola Traverso Alberto , Magistri Loredana , Gadducci Eleonora , Massardo Aristide Fausto , Olivieri Paolo
Published: August 2019

Climate change is driving the introduction of strict emission limits in the shipping sector favoring the introduction of alternative fuels, among which hydrogen. While the storage energy density of this energy vector is a key challenge that makes way to a variety of different solutions, from fossil fuel reformers to sodium borohydride systems, fuel cell systems are generally considered among the future ideal energy converters. Nevertheless very few fuel cell marine applications are available worldwide, none of them is related to a ship application, mainly because of the high power requirements. Fuel cells are relatively new in the shipping sector, up to now no civil industrial system has been commercialized yet while military applications rely only on the U212 submarine of the Italian and German Navy. The lack of favorable niche markets coupled with the strong conservative and traditional design principles held back the investment for optimized marine systems. For this reason, present and past projects made use of conveniently adapted automotive technologies into pilot demos, with particular focus on Proton Exchange Membrane Fuel Cell (PEMFC). However, ships requirements are largely different from automotive ones, not only for the power size that are in the range of MWs instead of kWs. On the other side, in order to take advantage of large scale production as well as of the modularity of fuel cell technology, the integrations of automotive or stationary based fuel cell subsystems, already available on the market, inside a dedicate modular marine system seems to be the solution pursued by many shipbuilders and contemplated by regulatory authorities. In hybrid system configurations, fuel cells are considered in combinations with batteries, another important technology under development, in order to take advantage of the superior energy performances of fuel cell systems and the highly power discharge dynamics of batteries. The need of fuel cell power systems for ships is pushing towards the creation of knowledge that requires laboratories able to challenge the abovementioned issues in order to give answers to shipbuilders and at a lower level also to rule makers.