bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative analysis of the PtO structure during photocatalytic water splitting by operando XAFS
Authors: Li Yu Hang , Li Chunzhong , Yang Hua Gui
Published: October 2017

Operando XAFS provides quantitative evidence of structural distortions of platinum oxide as an active site during photocatalytic water splitting.
Facile synthesis of multicolor photoluminescent polymer carbon dots with surface-state energy gap-controlled emission
Authors: Han Lei , Liu Shi Gang , Dong Jiang Xue , Liang Jia Yu , Li Ling Jie , Li Nian Bing , Luo Hong Qun
Published: October 2017

Yellow, green, and blue photoluminescent polymer carbon dots were prepared by a hydrothermal method and the multicolor photoluminescence mechanism was discussed.
4H-1,2,6-Thiadiazine-containing donor–acceptor conjugated polymers: synthesis, optoelectronic characterization and their use in organic solar cells
Authors: Chochos Christos L. , Kalogirou Andreas S. , Ye Tengling , Tatsi Elisavet , Katsouras Athanasios , Zissimou Georgia A. , Gregoriou Vasilis G. , Avgeropoulos Apostolos , Koutentis Panayiotis A.
Published: October 2017

A 4H-1,2,6-thiadiazine motif as a new acceptor for D–A conjugated polymers.
Depletion of MUC5B mucin in gastrointestinal cancer cells alters their tumorigenic properties: implication of the Wnt/β-catenin pathway
Authors: Lahdaoui Fatima , Messager Mathieu , Vincent Audrey , Hec Flora , Gandon Anne , Warlaumont Maxime , Renaud Florence , Leteurtre Emmanuelle , Piessen Guillaume , Jonckheere Nicolas , Mariette Christophe , Van Seuningen Isabelle
Published: October 2017

Secreted mucins are large O-glycosylated proteins that participate in the protection/defence of underlying mucosae in normal adults. Alteration of their expression is a hallmark of numerous epithelial cancers and has often been correlated to bad prognosis of the tumour. The secreted mucin MUC5B is overexpressed in certain subtypes of gastric and intestinal cancers, but the consequences of this altered expression on the cancer cell behaviour are not known. To investigate the role of MUC5B in carcinogenesis, its expression was knocked-down in the human gastric cancer cell line KATO-III and in the colonic cancer cell line LS174T by using transient and stable approaches. Consequences of MUC5B knocking-down on cancer cells were studied with respect to in vitro proliferation, migration and invasion, and in vivo on tumour growth using a mouse subcutaneous xenograft model. Western blotting, luciferase assay and qRT–PCR were used to identify proteins and signalling pathways involved. In vitro MUC5B down-regulation leads to a decrease in proliferation, migration and invasion properties in both cell lines. Molecular mechanisms involved the alteration of β-catenin expression, localization and activity and decreased expression of several of its target genes. In vivo xenografts of MUC5B-deficient cells induced a decrease in tumour growth when compared with MUC5B-expressing Mock cells. Altogether, the present study shows that down-regulation of MUC5B profoundly alters proliferation, migration and invasion of human gastrointestinal cancer cells and that these alterations may be, in part, mediated by the Wnt/β-catenin pathway emphasizing the potential of MUC5B as an actor of gastrointestinal carcinogenesis.
Characteristics and Treatment Outcomes of Benign Paroxysmal Positional Vertigo in a Cohort of Veterans
Authors: Akin Faith W. , Riska Kristal M. , Williams Laura , Rouse Stephanie B. , Murnane Owen D.
Published: October 2017

Background

The Mountain Home Veterans Affairs (VA) Medical Center has been diagnosing and treating veterans with benign paroxysmal positional vertigo (BPPV) for almost 2 decades. The clinic protocol includes a 2-week follow-up visit to determine the treatment outcome of the canalith repositioning treatment (CRT). To date, the characteristics of BPPV and treatment efficacy have not been reported in a cohort of veterans with BPPV.

Purpose

To determine the prevalence and characteristics of veterans diagnosed with BPPV in a Veterans Affairs Medical Center Audiology Clinic and to examine treatment outcomes.

Research Design

Retrospective chart review.

Study Sample

A total of 102 veterans who tested positive for BPPV in the Vestibular Clinic at the Mountain Home VA Medical Center from March 2010 to August 2011.

Results

In 102 veterans who were diagnosed with BPPV, the posterior semicircular canal was most often involved (75%), motion-provoked vertigo was the most common symptom (84%), and the majority (43%) were diagnosed with BPPV in their sixth decade. The prevalence of BPPV in the Audiology Vestibular Clinic was 15.6%. Forty-one percent of veterans reported a symptom onset within 12 months of treatment for BPPV; however, 36% reported their symptoms began > 36 months prior to treatment. CRT was effective (negative Dix–Hallpike/roll test) in most veterans (86%) following 1 treatment appointment (
M
= 1.6), but more than half reported incomplete symptom resolution (residual dizziness) at the follow-up appointment. Eighteen percent of veterans experienced a recurrence (
M
= 1.8 years;
SD
= 1.7 years).

Conclusions

The characteristics and treatment outcomes of BPPV in our veteran cohort was similar to what has been reported in the general population. Future work should focus on improving the timeliness of evaluation and treatment of BPPV and examining the time course and management of residual dizziness.
Semantic and Phonological Encoding Times in Adults Who Stutter: Brain Electrophysiological Evidence
Authors: Maxfield Nathan D.
Published: October 2017

Purpose

Some psycholinguistic theories of stuttering propose that language production operates along a different time course in adults who stutter (AWS) versus typically fluent adults (TFA). However, behavioral evidence for such a difference has been mixed. Here, the time course of semantic and phonological encoding in picture naming was compared in AWS (
n
= 16) versus TFA (
n
= 16) by measuring 2 event-related potential (ERP) components: NoGo N200, an ERP index of response inhibition, and lateralized readiness potential, an ERP index of response preparation.

Method

Each trial required a semantic judgment about a picture in addition to a phonemic judgment about the target label of the picture. Judgments were mapped onto a dual-choice (Go–NoGo/left–right) push-button response paradigm. On each trial, ERP activity time-locked to picture onset was recorded at 32 scalp electrodes.

Results

NoGo N200 was detected earlier to semantic NoGo trials than to phonemic NoGo trials in both groups, replicating previous evidence that semantic encoding generally precedes phonological encoding in language production. Moreover, N200 onset was earlier to semantic NoGo trials in TFA than in AWS, indicating that semantic information triggering response inhibition became available earlier in TFA versus AWS. In contrast, the time course of N200 activity to phonemic NoGo trials did not differ between groups. Lateralized readiness potential activity was influenced by strategic response preparation and, thus, could not be used to index real-time semantic and phonological encoding.

Conclusion

NoGo N200 results point to slowed semantic encoding in AWS versus TFA. Discussion considers possible factors in slowed semantic encoding in AWS and how fluency might be impacted by slowed semantic encoding.
How African American English-Speaking First Graders Segment and Rhyme Words and Nonwords With Final Consonant Clusters
Authors: Shollenbarger Amy J. , Robinson Gregory C. , Taran Valentina , Choi Seo-eun
Published: October 2017

Purpose

This study explored how typically developing 1st grade African American English (AAE) speakers differ from mainstream American English (MAE) speakers in the completion of 2 common phonological awareness tasks (rhyming and phoneme segmentation) when the stimulus items were consonant–vowel–consonant–consonant (CVCC) words and nonwords.

Method

Forty-nine 1st graders met criteria for 2 dialect groups: AAE and MAE. Three conditions were tested in each rhyme and segmentation task: Real Words No Model, Real Words With a Model, and Nonwords With a Model.

Results

The AAE group had significantly more responses that rhymed CVCC words with consonant–vowel–consonant words and segmented CVCC words as consonant–vowel–consonant than the MAE group across all experimental conditions. In the rhyming task, the presence of a model in the real word condition elicited more reduced final cluster responses for both groups. In the segmentation task, the MAE group was at ceiling, so only the AAE group changed across the different stimulus presentations and reduced the final cluster less often when given a model.

Conclusion

Rhyming and phoneme segmentation performance can be influenced by a child's dialect when CVCC words are used.
The Oral Narrative Comprehension and Production Abilities of Verbal Preschoolers on the Autism Spectrum
Authors: Westerveld Marleen F. , Roberts Jacqueline M. A.
Published: October 2017

Purpose

This study described the oral narrative comprehension and production skills of verbal preschool-age children on the autism spectrum and investigated correlations between oral narrative ability and norm-referenced language test performance.

Method

Twenty-nine preschool-age children (aged 4;0–5;9 years;months) with autism, who obtained an age-equivalent score of at least 36 months on the expressive communication subscale of the Vineland Adaptive Behavior Scales–Second Edition (Sparrow, Cicchetti, & Balla, 2005), participated. Children listened to an unfamiliar fictional narrative and answered comprehension questions afterward. After listening to the narrative a second time, children were asked to retell the narrative without picture support. Narratives were transcribed and analyzed for length, semantic diversity, grammatical complexity and accuracy, intelligibility, inclusion of critical events, and narrative stage.

Results

All children participated in the comprehension task, and 19 children produced an analyzable narrative retell. Compared with published data on typically developing children, significant difficulties were observed in narrative comprehension, intelligibility, and grammatical accuracy. Most of the children told descriptive or action sequences, with only 1 child producing an abbreviated episode. Significant positive correlations were found (a) between performance on the Peabody Picture Vocabulary Test–Fourth Edition (Dunn & Dunn, 2007) and semantic diversity and narrative comprehension and (b) between parent-reported receptive communication competence (Vineland Adaptive Behavior Scales–Second Edition) and narrative comprehension.

Conclusions

This study provides preliminary evidence of specific difficulties in oral narrative comprehension and production skills in verbal preschoolers on the autism spectrum.
Emergent Literacy Skills in Preschool Children With Hearing Loss Who Use Spoken Language: Initial Findings From the Early Language and Literacy Acquisition (ELLA) Study
Authors: Werfel Krystal L.
Published: October 2017

Purpose

The purpose of this study was to compare change in emergent literacy skills of preschool children with and without hearing loss over a 6-month period.

Method

Participants included 19 children with hearing loss and 14 children with normal hearing. Children with hearing loss used amplification and spoken language. Participants completed measures of oral language, phonological processing, and print knowledge twice at a 6-month interval. A series of repeated-measures analyses of variance were used to compare change across groups.

Results

Main effects of time were observed for all variables except phonological recoding. Main effects of group were observed for vocabulary, morphosyntax, phonological memory, and concepts of print. Interaction effects were observed for phonological awareness and concepts of print.

Conclusions

Children with hearing loss performed more poorly than children with normal hearing on measures of oral language, phonological memory, and conceptual print knowledge. Two interaction effects were present. For phonological awareness and concepts of print, children with hearing loss demonstrated less positive change than children with normal hearing. Although children with hearing loss generally demonstrated a positive growth in emergent literacy skills, their initial performance was lower than that of children with normal hearing, and rates of change were not sufficient to catch up to the peers over time.
Promoting Early Literacy for a Child in Foster Care
Authors: Farquharson Kelly
Published: October 2017

Beginning first grade with limited literacy skills creates a disadvantage for academic success. Alphabet knowledge, phonological awareness, and oral language skills are crucial for age-appropriate performance within most first grade curricula. Home literacy environments can help to create positive literacy and language experiences, but many children do not have stable homes in which to learn, thrive, and feel safe. In this case study, background information is presented for a child who is currently in foster care and has weak early literacy skills. Assessment and intervention plans are reviewed and recommendations for the foster parent are provided.
Literacy Difficulties in the Face of Multiple Factors: Using a Team Approach
Authors: Lund Emily
Published: October 2017

Because reading and writing are skills with a basis in oral language development, the speech-language-pathologist (SLP) should certainly play a role in intervention for children with literacy difficulties. SLPs provide vital information in the literacy assessment process, particularly in complicated cases. The purpose of this article is to describe the role of the SLP in the assessment of a Spanish-English bilingual second grade girl with a unilateral hearing loss who demonstrated delays in reading. Implications for clinical practice and indications for the involvement of the SLP are discussed.
On the Cusp of Middle School…With Minimal Reading and Writing Skills
Authors: Schuele C. Melanie , Young Kristina
Published: October 2017

This article uses a case study to consider how speech-language pathologists (SLPs) and the Individualized Education Program (IEP) team meets the challenges of students with speech sound disorder plus specific language impairment. The case study student is a fourth grader with intellectual skills in the normal range whose speech and language skills have not normalized. Multiple challenges are described and opportunities for collaboration are illustrated.
Detection of false data injection attacks against state estimation in smart grids based on a mixture Gaussian distribution learning method
Authors: Foroutan S. Armina , Salmasi Farzad R.
Published: October 2017

One of the most addressed attacks in power networks is false data injection (FDI) which affects monitoring, fault detection, and state estimation integrity by tampering measurement data. To detect such devastating attack, the authors propose a statistical anomaly detection approach based on Gaussian mixture model, while some appropriate machine learning approaches are evaluated for detecting FDI. It should be noted that a finite mixture model is a convex combination of some probability density functions and combining the properties of several probability functions, making the mixture models capable of approximating any arbitrary distribution. Simulations results confirm superior performance of the proposed method over conventional bad data detection (BDD) tests and other learning approaches that studied in this article. It should be noted that using data which change significantly over a day can be highly clustered, and therefore, detected much easier compared with small changes in the loads. So without loss of generality, in the simulations it is assumed that the power demand follows a uniform distribution in a small range. However, the detector can be trained regularly based on the updated load profile.
Three‐stage electric vehicle scheduling considering stakeholders economic inconsistency and battery degradation
Authors: Han Bing , Lu Shaofeng , Xue Fei , Jiang Lin , Xu Xiaotong
Published: October 2017

This study proposes an electric vehicle (EV) aggregator operation mechanism in a residential community. The EV charging and discharging operation behaviours are scheduled to maximise the EV aggregator revenue, while EV aggregator provides reserve service for the grid. This study not only considers the energy and information interactions between three stakeholders: EV aggregator, EV owners, and power grids, but also the economic interests of aggregator and owners are considered. The aggregator‐owner economic inconsistency issue (EV owners get higher charging cost in aggregator scheduling than self‐scheduling) is presented. In order to mediate this issue, a rebate factor is proposed. In the first stage, the objective is to minimise the day‐ahead (DA) charging cost of EV owners. Then the second stage is to maximise DA aggregator revenue with different rebate values. Finally, in the third stage, a real‐time scheduling strategy is proposed to maximise aggregator revenue using the optimal rebate value. In addition, the battery degradation in influencing scheduling is formulated. Scheduling results show the effectiveness of the proposed strategy, e.g. economic inconsistency of different parties can be mediated. Significant reduction of EV owners’ cost from self‐scheduling can be achieved while the revenue of EV aggregator is maximised under the proposed strategy.
Distributed multi‐agent control for combined AC/DC grids with wind power plant clusters
Authors: Gao Yang , Ai Qian
Published: October 2017

The combined AC/DC grids have, due to their technological features of high voltage and large capacity as well as operating flexibility and reliability, become one of the most potential solutions to connect large‐scale wind farms to power systems. The traditional centralised control lacks flexibility and robustness. In contrast, the distributed control is unable to simultaneously consider global optimum and response speed. A scheme of intelligent distributed control for combined AC/DC grids is proposed to constitute a multi‐agent system by equipping each terminal with an agent. While adopting the proposed control method, the optimisation of the upper layer is similar to the traditional grid dispatch and the lower layer system achieves the group compromise through the interaction and coordination among the agents and between the agents and the system. Based on the state information such as the voltage and the frequency of the neighbouring converter stations, the combined AC/DC grids can allocate the active power reasonably through the consistency control and provide the frequency support of the AC grid. Finally, four operating scenarios, including wind speed jump, wind power plant cluster disconnection, converter station failure and load demand response, are verified in a typical model of combined AC/DC grids by using the PSCAD/EMTDC software.
Transmission network expansion planning considering risk level assessment and scenario‐based risk level improvement
Authors: Shin Je‐Seok , Kim Jin‐O , Kim Sung‐Yul
Published: October 2017

Renewable energy sources (RESs) are actively connected with the grid, and thus the requirement for transmission network expansion planning has increased. When RESs are added to the grid as independent power plants under a deregulated power system structure, an independent system operator managing the transmission system should evaluate the impact of RES penetration. The system operator should restrict the capacity of the RES to be installed or perform transmission network expansion planning if necessary. This study proposes risk assessment (RA) based on an exponential risk level (RL) model to evaluate the negative effects of RES penetration and introduces a method of applying RA in scenario‐based transmission network expansion planning. The index of RL reduction via a scenario is formulated as an economic efficiency indicator for reducing the RL, based on the result of RA. A case study is performed on an actual power system in South Korea. For two cases based on the penetration of RESs, transmission network expansion planning considering the proposed RA is performed for several scenarios, and then, the best scenario for each case is selected.
High‐temperature Fabry–Perot interferometer based on mode analysis
Authors: Zhao Na , Lin Qijing , Jiang Weile , Jiang Zhuangde , Wu Zirong , Tian Bian , Zhang Zhongkai
Published: October 2017

An optical fibre Fabry–Perot interferometer (FPI) is proposed and experimentally demonstrated in this work. In the fast Fourier transform spectrum of the FPI transmission spectrum, a higher order model is separated from the transmission spectrum and the spatial frequency spectrum of the higher order model is detected. As the temperature changes, the shifts of the spatial frequency spectrum will be observed. The sensitivity of the temperature is 0.128 µm−1 K−1. The proposed sensor features the advantages of easy fabrication, compact structure and stable chemical property, and exhibits great potential in high‐temperature measurement.
The genusErymaMeyer, 1840 (Crustacea: Decapoda: Erymidae): new synonyms, systematic and stratigraphic implications
Authors: Devillez Julien , Charbonnier Sylvain
Published: October 2017

Among Erymidae Van Straelen, 1925 (Van Straelen V. 1925. Contribution à l'étude des crustacés décapodes de la période jurassique.Mémoires de la Classe des Sciences de l'Académie royale de Belgique7: 1–462), typical Mesozoic crustaceans, the genusErymaMeyer, 1840 (Meyer H. von. 1840a. Briefliche Mittheilungen.Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefactenkunde576–587) includes the largest number of species, mainly from Jurassic deposits. However, the lack of clear diagnoses for erymid genera has led to mistakes in generic assignments and to the establishment of redundant genera. The review of the concept ofErymaherein presents an attempt to clarify its diagnosis, mainly supported by the carapace groove pattern and the morphology of chelae of the first pair of pereiopods, and to emphasize its systematic implications. Thus, we maintain the synonymy ofKlytiaMeyer, 1840,BolinaMünster, 1839 (Münster G. 1839. Decapoda Macrura. Abbildung und Beschreibung der Fossilen Langschwänzigen Krebse in den Kalkschiefern von Bayern.Beiträge zur Petrefaktenkunde2: 1–88) (sensu Étallon [Étallon A. 1859. Description des crustacés fossiles de la Haute-Saône et du Haut-Jura.Bulletin de la Société géologique de France16: 169–205]), andErymastacusBeurlen, 1928 (Beurlen K. 1928. Die Decapoden des Schwäbischen Jura mit Ausnahme der aus den oberjurassischen Plattenkalken stammenden.Palaeontographica70: 115–278) withEryma. Moreover, a review of the generaProtoclytiopsisBirshtein, 1958 (Birshtein JA. 1958. Ein Vertreter der ältesten Ordo der Crustacea Decapoda Protoclitiopsis antiqua gen. nov. sp. nov. aus dem Permo West-Sibiriens.Doklady Akademii Nauk, SSSR122: 477–480), andGaliciaGarassino and Krobicki, 2002 (Garassino A, Krobicki M. 2002.Galicia marianaen. gen., n. sp. (Crustacea, Decapoda, Astacidea) from the Oxfordian (Upper Jurassic) of the Southern Polish Uplands.Bulletin of the Mizunami Fossil Museum29: 51–59), reveals the presence of a junction between the postcervical and branchiocardiac grooves. This feature is diagnostic ofErymaand supports the integration of these genera into the synonymy ofEryma. The addition ofProtoclytiopsisto the synonymy ofErymamakesEryma antiquum(Birshtein, 1958) nov. comb. the oldest representative of the genus and of the family, extending its stratigraphic range to the Late Permian (Changhsingian). Thus, this work also emphasizes that Erymidae crossed the Permian-Triassic boundary.
Mesozoic and Cenozoic decapod crustaceans from the Basque-Cantabrian basin (Western Pyrenees): new occurrences and faunal turnovers in the context of basin evolution
Authors: López-Horgue Mikel A. , Bodego Arantxa
Published: October 2017

Twenty-nine new identifications of fossil decapod crustacean remains in the Basque-Cantabrian Basin (Western Pyrenees) spanning from the Jurassic to the Miocene and coming from twenty-four new and five yet known localities are described here for the first time. These remains represent a substantial advance in the knowledge of these faunas and their diversity in this basin, giving an accurate image of the decapod faunal succession. The study includes a taxonomical description and discussion with reference to the known occurrences. Their accurate dating and the environmental ascription have been possible after the analysis of the stratigraphic occurrence in the context of a well-known basinal stratigraphy. This has ultimately permitted a brief analysis of the decapod palaeoecology and faunal turnovers in the context of basin evolution.
The Gaussian cannon
Authors: Andersson Åke , Karlsson Carl-Joar , Lane Hampus
Published: October 2017

This report studies different properties of a Gaussian cannon. The cannon’s firing velocity is measured for a varying number of steel balls, varying input velocity and different geometries of the cannon. By measuring the attractive force from the magnet on the balls a mapping of the potential energy for the firing process is acquired. It is found that the firing of a Gaussian cannon can be modeled as successive collisions between the magnet and its neighboring balls, and between successive balls. To reach the highest possible ejection speed with a trigger ball that is released from rest, a chained cannon should be used. The optimal number of balls on each individual cannon depends on magnetization energies and coefficients of restitution.
Epidemic spreading between two coupled subpopulations with inner structures
Authors: Ruan Zhongyuan , Tang Ming , Gu Changgui , Xu Jinshan
Published: October 2017

The structure of underlying contact network and the mobility of agents are two decisive factors for epidemic spreading in reality. Here, we study a model consisting of two coupled subpopulations with intra-structures that emphasizes both the contact structure and the recurrent mobility pattern of individuals simultaneously. We show that the coupling of the two subpopulations (via interconnections between them and round trips of individuals) makes the epidemic threshold in each subnetwork to be the same. Moreover, we find that the interconnection probability between two subpopulations and the travel rate are important factors for spreading dynamics. In particular, as a function of interconnection probability, the epidemic threshold in each subpopulation decreases monotonously, which enhances the risks of an epidemic. While the epidemic threshold displays a non-monotonic variation as travel rate increases. Moreover, the asymptotic infected density as a function of travel rate in each subpopulation behaves differently depending on the interconnection probability.
First passage, looping, and direct transition in expanding and narrowing tubes: Effects of the entropy potential
Authors: Berezhkovskii Alexander M. , Dagdug Leonardo , Bezrukov Sergey M.
Published: October 2017

We study transitions of diffusing particles between the left and right ends of expanding and narrowing conical tubes. In an expanding tube, such transitions occur faster than in the narrowing tube of the same length and radius variation rate. This happens because the entropy potential pushes the particle towards the wide tube end, thus accelerating the transitions in the expanding tube and slowing them down in the narrowing tube. To gain deeper insight into how the transitions occur, we divide each trajectory into the direct-transit and looping segments. The former is the final part of the trajectory, where the particle starting from the left tube end goes to the right end without returning to the left one. The rest of the trajectory is the looping segment, where the particle, starting from the left tube end, returns to this end again and again until the direct transition happens. Our focus is on the durations of the two segments and their sum, which is the duration of the particle first passage between the left and right ends of the tube. We approach the problem using the one-dimensional description of the particle diffusion along the tube axis in terms of the modified Fick-Jacobs equation. This allows us to derive analytical expressions for the Laplace transforms of the probability densities of the first-passage, direct-transit, and looping times, which we use to find the mean values of these random variables. Our results show that the direct transits are independent of the entropy potential and occur as in free diffusion. However, this “free diffusion” occurs with the effective diffusivity entering the modified Fick-Jacobs equation, which is smaller than the particle diffusivity in a cylindrical tube. This is the only way how the varying tube geometry manifests itself in the direct transits. Since direct-transit times are direction-independent, the difference in the first-passage times in the tubes of the two types is due to the difference in the durations of the looping segments in the expanding and narrowing tubes. Obtained analytical results are supported by three-dimensional Brownian dynamics simulations.
Magnetic dipolar ordering and hysteresis of geometrically defined nanoparticle clusters
Authors: Kure Mathias , Beleggia Marco , Frandsen Cathrine
Published: October 2017

Magnetic nanoparticle clusters have several biomedical and engineering applications, and revealing the basic interplay between particle configuration and magnetic properties is important for tuning the clusters for specific uses. Here, we consider the nanoparticles as macrospins and use computer simulations to determine their magnetic configuration when placed at the vertices of various polyhedra. We find that magnetic dipoles of equal magnitude arrange in flux-closed vortices on a layer basis, giving the structures a null remanent magnetic moment. Assigning a toroidal moment to each layer, we find that the geometrical arrangement, i.e., “triangular packing” vs. “square packing,” of the moments in the adjacent layer determines whether the flux-closed layers are ferrotoroidal (co-rotating vortices) or antiferrotoroidal (counter-rotating vortices). Interestingly, upon adding a single magnetic moment at the center of the polyhedra, the central moment relaxes along one of the principal axes and induces partial alignment of the surrounding moments. The resulting net moment is up to nearly four times that of the single moment added. Furthermore, we model quasi-static hysteresis loops for structures with and without a central moment. We find that a central moment ensures an opening of the hysteresis loop, and the resultant loop areas are typically many-fold larger compared to the same structure without a central moment.
The effect of electron transport on the characterization of x-ray free-electron laser pulses via ablation
Authors: Hau-Riege Stefan P. , Pardini Tom
Published: October 2017

The spatial intensity distribution of x-ray free-electron laser (XFEL) pulses in-focus is commonly characterized by performing ablative imprints in thin gold films on silica substrates. In many cases, the range of the electrons generated in the gold by x-ray absorption far exceeds the beam size, and so, it is not clear if the results of imprint studies are compromised by electron transport. Thermal conduction could further modify the energy density profile in the material. We used a combination of Monte-Carlo transport and continuum models to quantify the accuracy of the imprint method for characterizing XFEL beam profiles. We found that for x-ray energies in the range of 1 to 10 keV, the actual and the measured beam diameters agree within 12% or better for beam diameters between 0.1 and 1 μm.
Decoupling of translational and rotational diffusion in quasi-2D colloidal fluids
Authors: Vivek Skanda , Weeks Eric R.
Published: October 2017

We observe the translational and rotational diffusion of dimer tracer particles in quasi-2D colloidal samples. The dimers are in dense samples of two different sizes of spherical colloidal particles, with the area fraction ϕ of the particles varying from dilute to nearly glassy. At low ϕ, rotational and translational diffusion have a ratio set by the dimer size, as expected. At higher ϕ, dimers become caged by their neighboring particles, and both rotational and translational diffusion become slow. For short dimers, we observe rapid reorientations so that the rotational diffusion is faster than the translational diffusion: the two modes of diffusion are decoupled and have different ϕ dependence. Longer dimers do not exhibit fast rotations, and we find that their translational and rotational diffusion stay coupled for all ϕ. Our results bridge prior results that used spheres (very fast rotation) and long ellipsoids (very slow rotation).
A microfluidic approach for hemoglobin detection in whole blood
Authors: Taparia Nikita , Platten Kimsey C. , Anderson Kristin B. , Sniadecki Nathan J.
Published: October 2017

Diagnosis of anemia relies on the detection of hemoglobin levels in a blood sample. Conventional blood analyzers are not readily available in most low-resource regions where anemia is prevalent, so detection methods that are low-cost and point-of-care are needed. Here, we present a microfluidic approach to measure hemoglobin concentration in a sample of whole blood. Unlike conventional approaches, our microfluidic approach does not require hemolysis. We detect the level of hemoglobin in a blood sample optically by illuminating the blood in a microfluidic channel at a peak wavelength of 540 nm and measuring its absorbance using a CMOS sensor coupled with a lens to magnify the image onto the detector. We compare measurements in microchannels with channel heights of 50 and 115 μm and found the channel with the 50 μm height provided a better range of detection. Since we use whole blood and not lysed blood, we fit our data to an absorption model that includes optical scattering in order to obtain a calibration curve for our system. Based on this calibration curve and data collected, we can measure hemoglobin concentration within 1 g/dL for severe cases of anemia. In addition, we measured optical density for blood flowing at a shear rate of 500 s-1 and observed it did not affect the nonlinear model. With this method, we provide an approach that uses microfluidic detection of hemoglobin levels that can be integrated with other microfluidic approaches for blood analysis.
Removal of singularity in radial Langmuir probe models for non-zero ion temperature
Authors: Regodón Guillermo Fernando , Fernández Palop José Ignacio , Tejero-del-Caz Antonio , Díaz-Cabrera Juan Manuel , Carmona-Cabezas Rafael , Ballesteros Jerónimo
Published: October 2017

We solve a radial theoretical model that describes the ion sheath around a cylindrical Langmuir probe with finite non-zero ion temperature in which singularity in an a priori unknown point prevents direct integration. The singularity appears naturally in fluid models when the velocity of the ions reaches the local ion speed of sound. The solutions are smooth and continuous and are valid from the plasma to the probe with no need for asymptotic matching. The solutions that we present are valid for any value of the positive ion to electron temperature ratio and for any constant polytropic coefficient. The model is numerically solved to obtain the electric potential and the ion population density profiles for any given positive ion current collected by the probe. The ion-current to probe-voltage characteristic curves and the Sonin plot are calculated in order to use the results of the model in plasma diagnosis. The proposed methodology is adaptable to other geometries and in the presence of other presheath mechanisms.
Competition between the inter-valley scattering and the intra-valley scattering on magnetoconductivity induced by screened Coulomb disorder in Weyl semimetals
Authors: Ji Xuan-Ting , Lu Hai-Zhou , Zhu Zhen-Gang , Su Gang
Published: October 2017

Recent experiments on Weyl semimetals reveal that charged impurities may play an important role. We use a screened Coulomb disorder to model the charged impurities, and study the magneto-transport in a two-node Weyl semimetal. It is found that when the external magnetic field is applied parallel to the electric field, the calculated longitudinal magnetoconductivity shows positive in the magnetic field, which is just the negative longitudinal magnetoresistivity (LMR) observed in experiments. When the two fields are perpendicular to each other, the transverse magnetoconductivities are measured. It is found that the longitudinal (transverse) magnetoconductivity is suppressed (enhanced) sensitively with increasing the screening length. This feature makes it hardly to observe the negative LMR in Weyl semimetals experimentally owing to a small screening length. Our findings gain insight into further understanding on recently actively debated magneto-transport behaviors in Weyl semimetals. Furthermore we studied the relative weight of the inter-valley scattering and the intra-valley scattering. It shows that the former is as important as the latter and even dominates in the case of strong magnetic fields and small screening length. We emphasize that the discussions on inter-valley scattering is out of the realm of one-node model which has been studied.
Host-derived fatty acids activate type VII secretion inStaphylococcus aureus
Authors: Lopez Michael S. , Tan Irene S. , Yan Donghong , Kang Jing , McCreary Mark , Modrusan Zora , Austin Cary D. , Xu Min , Brown Eric J.
Published: October 2017

Significance

Staphylococcus aureusis one of the most adaptable and prolific human pathogens, and it employs an arsenal of virulence factors to infect blood, bone, and soft tissues. The type VII secretion system (T7SS) is a dedicated virulence protein-secretion pathway that enables long-term survival of the bacteria in abscesses, where they are protected from host immune cells. Here we report that host-derived fatty acids are incorporated into theS.aureusmembrane, altering bacterial membrane properties and activating the expression of the T7SS. Thus, this work identifies a mechanism by which an important human pathogen senses unique elements of the host environment and implements the expression of specific genes that enable bacterial survival and thereby promote human disease.
Short- and long-term effects of imprisonment on future felony convictions and prison admissions
Authors: Harding David J. , Morenoff Jeffrey D. , Nguyen Anh P. , Bushway Shawn D.
Published: October 2017

Significance

Between the 1970s and the late 2000s, the United States experienced an enormous rise in incarceration, a substantial portion of which was caused by high rates of return to prison among those previously incarcerated. This study shows that such returns are primarily a product of postprison community supervision rather than criminogenic effects of imprisonment, as many individuals sentenced to prison become trapped in the escalating surveillance and punishment of the criminal justice system. In other words, the rise in incarceration in the United States in the late 20th and early 21st centuries was in part a self-perpetuating process resulting from the workings of the criminal justice system itself.
Simultaneous two-photon imaging of intracellular chloride concentration and pH in mouse pyramidal neurons in vivo
Authors: Sulis Sato Sebastian , Artoni Pietro , Landi Silvia , Cozzolino Olga , Parra Riccardo , Pracucci Enrico , Trovato Francesco , Szczurkowska Joanna , Luin Stefano , Arosio Daniele , Beltram Fabio , Cancedda Laura , Kaila Kai , Ratto Gian Michele
Published: October 2017

Significance

The control of intracellular Cl
−
and pH plays a crucial role in several neuronal functions, and the study of these processes would be helped by tools for their noninvasive optical measurement in vivo. In this study, we have performed combined measurements of Cl
−
and pH of individual pyramidal neurons by means of in vivo two-photon imaging, and we provide direct experimental demonstration for the presence of the postnatal developmental shift to lower intraneuronal Cl
−
. Moreover, we introduce an approach for dynamic and simultaneous monitoring of intraneuronal Cl
−
and pH in vivo. These methods will open a window for the study of the roles of intraneuronal pH and Cl
−
in neuronal signaling, plasticity, and disease.
Phenotypic variation explains food web structural patterns
Authors: Gibert Jean P. , DeLong John P.
Published: October 2017

Significance

Understanding food web structure—networks of species and their feeding interactions—is central to predicting how ecosystems may respond to climate change. Feeding interactions are often determined by the traits individuals have, but how the effects of such traits and their intraspecific variation scale up from individuals to food webs is not known. Here, we use mathematical models to show that trait variation influences predator connectivity and trophic level within food webs. By doing so, we predict the occurrence of important structural features in food webs, and we confirm these predictions using a large global dataset of the best-resolved available food webs.
Tree genetics defines fungal partner communities that may confer drought tolerance
Authors: Gehring Catherine A. , Sthultz Christopher M. , Flores-Rentería Lluvia , Whipple Amy V. , Whitham Thomas G.
Published: October 2017

Significance

Soil microbes influence plant performance and may be critical to the persistence of some plants with climate change. However, microbes are highly diverse, and individuals of the same plant species often associate with different microbes. We examined the importance of soil microbes to the growth and survival of a widespread pine under drought conditions. We found that specific beneficial fungus–host genotype combinations promoted drought tolerance in field and greenhouse studies. Drought tolerance, and associations with particular fungi, were passed from mother trees to their offspring, indicating the traits are genetic. These results demonstrate the interlinked importance of the genetics of a tree and its microbiome, which can be used to restore forest losses resulting from drought.
On the origin of biological construction, with a focus on multicellularity
Authors: van Gestel Jordi , Tarnita Corina E.
Published: October 2017

Biology is marked by a hierarchical organization: all life consists of cells; in some cases, these cells assemble into groups, such as endosymbionts or multicellular organisms; in turn, multicellular organisms sometimes assemble into yet other groups, such as primate societies or ant colonies. The construction of new organizational layers results from hierarchical evolutionary transitions, in which biological units (e.g., cells) form groups that evolve into new units of biological organization (e.g., multicellular organisms). Despite considerable advances, there is no bottom-up, dynamical account of how, starting from the solitary ancestor, the first groups originate and subsequently evolve the organizing principles that qualify them as new units. Guided by six central questions, we propose an integrative bottom-up approach for studying the dynamics underlying hierarchical evolutionary transitions, which builds on and synthesizes existing knowledge. This approach highlights the crucial role of the ecology and development of the solitary ancestor in the emergence and subsequent evolution of groups, and it stresses the paramount importance of the life cycle: only by evaluating groups in the context of their life cycle can we unravel the evolutionary trajectory of hierarchical transitions. These insights also provide a starting point for understanding the types of subsequent organizational complexity. The central research questions outlined here naturally link existing research programs on biological construction (e.g., on cooperation, multilevel selection, self-organization, and development) and thereby help integrate knowledge stemming from diverse fields of biology.
Motor origin of temporal predictions in auditory attention
Authors: Morillon Benjamin , Baillet Sylvain
Published: October 2017

Significance

How the motor system participates in auditory perception is unknown. In a magnetoencephalography experiment involving auditory temporal attention, we show that the left sensorimotor cortex encodes temporal predictions, which drive the precise temporal anticipation of forthcoming sensory inputs. This encoding is associated with bursts of beta (18–24 Hz) neural oscillations that are directed toward auditory regions. Our data also show that the production of overt movements improves the quality of temporal predictions and augments auditory task performance. These behavioral changes are associated with increased signaling of temporal predictions in right-lateralized frontoparietal associative regions. This study points at a covert form of auditory active sensing, and emphasizes the fundamental role of motor brain areas and actual motor behavior in sensory processing.
Temporal calcium profiling of specific circadian neurons in freely moving flies
Authors: Guo Fang , Chen Xiao , Rosbash Michael
Published: October 2017

Significance

Monitoring neuronal activity in freely moving, behaving animals is a holy grail of neuroscience. Here we present a noninvasive tool that links the calcium profiles of specific fly neurons to real-time behavior. Optogenetic manipulation of two groups of circadian neurons indicates that they drive sleep or locomotor activity. The two calcium patterns are also distinct and couple well to the sleep/activity phases of fly behavior. The sleep-promoting neurons appear more active when the flies initiate daytime sleep, whereas the activity-promoting neurons appear to fire more strongly coincident with the evening locomotor activity peak. This new approach is complementary to electrophysiological recording and GCaMP imaging, especially for small organisms and behavorial paradigms for which these more traditional methods are not practical.
High-intensity urban light installation dramatically alters nocturnal bird migration
Authors: Van Doren Benjamin M. , Horton Kyle G. , Dokter Adriaan M. , Klinck Holger , Elbin Susan B. , Farnsworth Andrew
Published: October 2017

Significance

Artificial light at night is a novel stimulus in the evolutionary history of nocturnal animals. Light pollution can significantly alter these organisms’ behaviors, from migration to foraging to vocal communication. Nocturnally migrating birds are particularly susceptible to artificial light because of adaptations and requirements for navigating and orienting in darkness. However, light’s effects on in-flight behaviors have not been well quantified, especially in urbanized environments. Here we report that an iconic urban light installation dramatically altered multiple behaviors of nocturnally migrating birds—but these effects disappeared when lights were extinguished. We recommend selective removal of light pollution during nights with substantial bird migration to mitigate negative effects on birds, in particular collisions with lighted structures.
Origin of the RNA world: The fate of nucleobases in warm little ponds
Authors: Pearce Ben K. D. , Pudritz Ralph E. , Semenov Dmitry A. , Henning Thomas K.
Published: October 2017

Significance

There are currently two competing hypotheses for the site at which an RNA world emerged: hydrothermal vents in the deep ocean and warm little ponds. Because the former lacks wet and dry cycles, which are well known to promote polymerization (in this case, of nucleotides into RNA), we construct a comprehensive model for the origin of RNA in the latter sites. Our model advances the story and timeline of the RNA world by constraining the source of biomolecules, the environmental conditions, the timescales of reaction, and the emergence of first RNA polymers.