bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency of circulating subpopulations of T‐regulatory cells in patients with hidradenitis suppurativa
Authors: Hessam S. , Gambichler T. , Höxtermann S. , Skrygan M. , Sand M. , Garcovich S. , Meyer T. , Stockfleth E. , Bechara F.G.
Published: November 2019

Background

Decreased number of T‐regulatory cells (Tregs) and/or their loss of function potentially lead to uncontrolled immune‐mediated inflammatory responses. There are only few data available on Tregs in hidradenitis suppurativa (HS) – a disease in which it has been suggested that host immune factors and an overactive immune system of the follicular epithelium play a pathogenetic role.

Objectives

To analyse frequencies of Tregs subpopulations in blood of HS patients in comparison with a healthy control group.

Materials & methods

Blood samples obtained from HS patients and healthy controls were evaluated by flow cytometry and enzyme‐linked immunosorbent assay.

Results

The frequency of natural Tregs among CD4+ T lymphocytes were significantly reduced in the HS group compared to the healthy controls. The proportion of activated Tregs, non‐suppressive Tregs and proliferating Tregs showed no significant difference when compared to controls. Regarding Tregs frequencies, there was no significant difference between the three Hurley stages. Serum concentrations of IL‐10, TGF‐ß1 and IL‐17A did not show significant differences between the HS and control group.

Conclusion

The reduction of natural Tregs observed in blood of HS patients could be the result of Tregs homing to sites of inflammatory hot spots in HS skin. Further studies are justified evaluating the role of circulating Tregs during the evolution of HS lesions and as a biomarker for treatment response.
Adverse events with IL‐17 and IL‐23 inhibitors for psoriasis and psoriatic arthritis: a systematic review and meta‐analysis of phase III studies
Authors: Loft N.D. , Vaengebjerg S. , Halling A.‐S. , Skov L. , Egeberg A.
Published: November 2019

Biologics targeting interleukin (IL)‐17 and IL‐23 are generally well‐tolerated and considered safe, though adverse events are seen more often compared with placebo. The objectives of this systematic review and meta‐analysis were to assess the prevalence of adverse events in patients with psoriasis or psoriatic arthritis with any adverse events after 12, 16, 24 and 52 weeks of treatment with IL‐17 or IL‐23 inhibitors. Two independent authors searched the databases PubMed and EMBASE for studies reporting on adverse events in phase 3 trials of IL‐17 and IL‐23 inhibitors for patients with psoriasis and psoriatic arthritis. The study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. Data synthesis was performed using a random‐effects model. In total, 44 publications (43 studies) were included in the analyses. The proportion of patients with any adverse events for all treatments pooled were 0.57 [95% confidence interval (CI): 0.55–0.59] after 12 weeks, 0.52 (95% CI: 0.49–0.55) after 16 weeks, 0.72 (95% CI: 0.66–0.78) after 24 weeks and 0.81 (95% CI: 0.76–0.86) after 52 weeks. Across therapies, the most prevalent AEs were infections, nasopharyngitis and headache. For ixekizumab one of the most prevalent AEs was injection site reactions, reported in 15.7% of the patients after 52 weeks. Overall, IL‐17 and IL‐23 inhibitors appear to be well‐tolerated with good safety profiles. Our findings may aid the clinical decision making when choosing the most appropriate therapy for patients with moderate‐to‐severe psoriasis.
Enriching the quality of cross‐cultural instrument development through cognitive interviewing: Implications for nursing research
Authors: Jang Min Kyeong , Kim Sue , Collins Eileen G. , Quinn Lauretta T. , Park Chang G. , Ferrans Carol E.
Published: November 2019

Aim

During cross‐cultural instrument development, a gap commonly exists between the intended meaning of questionnaire items and the extent to which the participant understands that meaning. Because cognitive interviewing can provide such a powerful means for ensuring an accurate interpretation of items, the purpose of this report is to provide a practical guide to encourage its use in nursing research.

Methods

This report provides in‐depth information describing: (a) advantages of cognitive interviewing, particularly for cross‐cultural instrument development; (b) specific problems it can identify and solve; (c) strategies for performing cognitive interviews, including the four‐step model of the question‐and‐answer process; (d) practical guidance for conducting successful cognitive interviews.

Results

To achieve linguistic validity as well as cultural relevance, a variety of factors need to be considered in addition to language, such as cultural interpretations, attitudes, and values. Examples of health‐related studies are presented, demonstrating the advantages of cognitive interviewing for instrument development and cross‐cultural research. These examples show how cognitive interviewing can be productively used to verify question clarity, patient comprehension, and patients' ease of response and judgment while also helping to establish content validity based on patients' perspectives.

Conclusions

Cognitive interviewing can help nurse researchers discover potential instrument flaws and correct them in advance, subsequently avoiding collection of inaccurate data. Thus, cognitive interviewing should be considered an effective pretesting method for development of accurate instruments, particularly in cross‐cultural nursing research.
In situ heating TEM observations of evolving nanoscale Al–Mg–Si–Cu precipitates
Authors: SUNDE JONAS KRISTOFFER , WENNER SIGURD , HOLMESTAD RANDI
Published: November 2019

This research concerns the precipitation and subsequent dissolution of precipitate phases in an Al–0.86Mg–0.62Si–0.1Cu (at.%) alloy subjected to varying thermal exposure during an in situ heating transmission electron microscope (TEM) experiment. The distribution and crystal structure of precipitates were determined by a scanning diffraction approach at multiple stages, pinpointing the precipitates that underwent phase transformations during heating. Obtained results were compared with TEM studies of the material heated ex situ. This revealed differences in the transformation kinetics of precipitates in an electron transparent lamella (thickness ) to that of macroscopic bulk specimens.

Lay Description

The precipitate phases that are formed in age‐hardenable Al alloys are conventionally studied using the TEM, with electron transparent specimens prepared from bulk materials heat treated for various times. We demonstrate here that the growth, phase transformation and subsequent dissolution of precipitate phases in the Al–Mg–Si–Cu system can be studied successfully by in situ heating TEM. Imaging and scanning diffraction combined with data postprocessing were used to study the distribution and structure of transforming precipitates. This enabled us to track the precipitates that underwent phase transformations during heating, hence offering a direct quantitative assessment of the precipitation occurring in these materials. The narrow thickness of the electron transparent specimen (≈90 nm) may potentially have affected the resulting precipitation. Therefore, thickness effects were assessed by comparing obtained results with TEM studies of ex situ heated bulk specimens.
Co‐administration of ethanol and nicotine heightens sensitivity to ethanol reward within the nucleus accumbens (NAc) shell and increasing NAc shell BDNF is sufficient to enhance ethanol reward in naïve Wistar rats
Authors: Waeiss Robert A. , Knight Christopher P. , Engleman Eric A. , Hauser Sheketha R. , Rodd Zachary A.
Published: November 2019

Alcohol use disorder most commonly presents as a polydrug disorder where greater than 85% are estimated to smoke. EtOH and nicotine (NIC) co‐abuse or exposure results in unique neuroadaptations that are linked to behaviors that promote drug use. The current experiments aimed to identify neuroadaptations within the mesolimbic pathway produced by concurrent EtOH and NIC exposure. The experiments used four overall groups of male Wistar rats consisting of vehicle, EtOH or NIC alone, and EtOH+NIC. Drug exposure through direct infusion into the posterior ventral tegmental area (pVTA) stimulated release of glutamate and dopamine in the nucleus accumbens (NAc) shell, which was quantified through high‐performance liquid chromatography. Additionally, brain‐derived neurotrophic factor (BDNF) protein levels were measured via enzyme‐linked immunosorbent assay (ELISA). A second experiment investigated the effects of drug pretreatment within the pVTA on the reinforcing properties of EtOH within the NAc shell through intracranial self‐administration (ICSA). The concluding experiment evaluated the effect of NAc shell pretreatment with BDNF on EtOH reward utilizing ICSA within that region. The data indicated that only EtOH+NIC administration into the pVTA simultaneously increased glutamate, dopamine, and BDNF in the NAc shell. Moreover, only pVTA pretreatment with EtOH+NIC enhanced the reinforcing properties of EtOH in the NAc shell. BDNF pretreatment in the NAc shell was also sufficient to enhance the reinforcing properties of EtOH in the NAc shell. The collected data suggest that concurrent EtOH+NIC exposure results in a distinct neurochemical response and neuroadaptations within the mesolimbic pathway that alter EtOH reward.

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Differential Subsampling with Cartesian Ordering for Ultrafast High‐Resolution MRA in the Assessment of Intracranial Aneurysms
Authors: Nael Kambiz , Drummond James , Costa Anthony B. , De Leacy Reade A. , Fung Maggie M. , Mocco J
Published: November 2019

BACKGROUND AND PURPOSE

We aimed to evaluate the feasibility of an ultrafast whole head contrast‐enhanced MRA (CE‐MRA) in morphometric assessment of intracranial aneurysms in comparison to routinely used time‐of‐flight (TOF)‐MRA.

METHODS

In this prospective single institutional study, patients with known untreated intracranial aneurysm underwent MRA. Routine multislab TOF‐MRA was obtained with a 3D voxel sizes of .6 × .6 × 1 (6‐minute acquisition time). CE‐MRA of whole head was obtained using Differential Subsampling with Cartesian Ordering (DISCO) and 2D Auto‐calibrating Reconstruction for Cartesian imaging with a 3D voxel‐sizes of .75 × .75 × 1 mm3 during a 6‐second temporal resolution. Morphometric features of intracranial aneurysms, including size, aneurysm sac morphology, and the presence of intraluminal thrombosis, were assessed on both techniques. Statistical analysis was performed using a combination of Kappa test, Bland‐Altman, and correlation coefficient analysis.

RESULTS

A total of 34 aneurysms in 28 patients were included. Aneurysm size measurements (mean ± SD) were similar between DISCO‐MRA (4.1 ± 2.3 mm) and TOF‐MRA (4.3 ± 2.8 mm) (P = .27). Bland‐Altman analysis showed a mean difference of .4 mm and there was excellent correlation r = .91 (95% CI: .87‐.96). In six aneurysms (17.6%), TOF‐MRA was nonconfidant to exclude intraluminal thrombosis. In seven aneurysms (20%), TOF‐MRA was unable or nonconfidant in depicting aneurysm sac morphology.

CONCLUSIONS

Described ultrafast high spatial‐resolution MRA is superior to routinely used TOF‐MRA in assessment of morphometric features of intracranial aneurysms, such as intraluminal thrombosis and aneurysm morphology, and is obtained in a fraction of the time (6 seconds).
CircZNF609/miR-134-5p/BTG-2 axis regulates proliferation and migration of glioma cell
Authors: Tong Hui , Zhao Kai , Wang Jiangjie , Xu Hui , Xiao Jianqi
Published: November 2019

Objectives

MicroRNAs are abundant in eukaryotic cells and play key roles in cancers. Circular RNAs (CircRNAs) served as the competing endogenous RNAs (ceRNAs) in mediating multiple cell processes. This study aims to define the role of CircRNA CircZNF609/miR-134-5p in glioma as well as the underlying regulating mechanism.

Methods

Relative expression of miR-134-5p, CircZNF609 and BTG-2 mRNA was determined by quantitative real-time PCR. Cell proliferation was analysed by CCK-8 assay. Cell migration was assessed by cell wound scratch assay. The direct regulatory of miR-134-5p on BTG-2 and CircZNF609 was verified by luciferase report gene assay.

Key findings

MiR-134-5p was significantly upregulated in glioma cells. The overexpression of miR-134-5p inhibited cell proliferation and migration of glioma cell U251 and U87. Reversely, knock-down of miR-134-5p enhanced cell proliferation and migration. Both BTG-2 and CircZNF609 are the direct targets of miR-134-5p, and their expression could be negatively regulated by miR-134-5p. CircZNF609 was significantly upregulated in U251 and U87 cells and acted as an oncogene to promote cell proliferation and cell migration of glioma cell U251 and U87.

Conclusions

These data proved that CircZNF609 served as a competing RNA to bind miR-134-5p that promoted BTG-2 expression leading to reduced proliferation and migration of glioma cell.
Resilience to Freezing in the Vegetative Cells of the Microalga Lobosphaera incisa (Trebouxiophyceae, Chlorophyta)
Authors: Kugler Amit , Kumari Puja , Kokabi Kamilya , Itkin Maxim , Malitsky Sergey , Khozin‐Goldberg Inna
Published: November 2019

The chlorophyte microalga Lobosphaera incisa was isolated from the snowy slopes of Mt. Tateyama in Japan. This microalga stores exceptionally high amounts of the omega‐6 LC‐PUFA arachidonic acid in triacylglycerols, and therefore represents a potent photosynthetic source for this essential LC‐PUFA. Assuming that freezing tolerance may play a role in adaptation of L. incisa to specific ecological niches, we examined the capability of L. incisa to tolerate extreme sub‐zero temperatures. We report here, that the vegetative cells of L. incisa survived freezing at −20°C and −80°C (over 1 month), without cryoprotective agents or prior treatments. Cells successfully recovered upon thawing and proliferated under optimal growth conditions (25°C). However, cells frozen at −80°C showed better recovery and lower cellular ROS generation upon thawing, compared to those preserved at −20°C. Photosynthetic yield of PSII, estimated by Fv/Fm, temporarily decreased at day 1 post freezing and resumed to the original level at day 3. Interestingly, the thawed algal cultures produced a higher level of chlorophylls, exceeding the control culture. The polar metabolome of the vegetative cells comprised a range of compatible solutes, dominated by glutamate, sucrose, and proline. We posit that the presence of endogenous cryoprotectants, a rigid multilayer cell wall, the high LC‐PUFA content in membrane lipids, and putative cold‐responsive proteins may contribute to the retention of functionality upon recovery from the frozen state, and therefore for the survival under cryospheric conditions. From the applied perspective, this beneficial property holds promise for the cryopreservation of starter cultures for research and commercial purposes.
Ambulatory assessment of colonic motility using the electromagnetic capsule tracking system: Effect of opioids
Authors: Mark Esben Bolvig , Klinge Mette Winther , Grønlund Debbie , Poulsen Jakob Lykke , Schlageter Vincent , Scott S. Mark , Krogh Klaus , Drewes Asbjørn Mohr
Published: November 2019

Background

Opioid treatment often causes debilitating constipation. However, it is not well described how opioids affect colonic motility and whether opioid‐induced constipation is due to either a decrease of powerful peristaltic contractions or “uncoordinated” peristalsis. The present study aims to investigate the effect of oxycodone on parameters of colonic motility and to determine whether motility is normalized by the opioid antagonist naloxegol.

Methods

In two randomized, double‐blind crossover trials, oxycodone or placebo was administered to 25 healthy males (Trial A), while another 24 healthy males were administered oxycodone with naloxegol or placebo (Trial B). Colonic motility was assessed by tracking the progression of an electromagnetic capsule throughout the large intestine. Segmental colonic transit times and capsule movements were calculated using displacement distance and velocity.

Key Results

In Trial A, colonic transit time increased during oxycodone treatment compared with placebo (39 vs 18 hours, P < .01). Displacement during long fast antegrade movements was shorter during oxycodone treatment than with placebo (10 vs 20 cm, P = .03). In Trial B, colonic transit time was faster during oxycodone + naloxegol than during oxycodone + placebo (40 vs 55 hours, P = .049), mainly caused by an increase of the percentwise fraction of distance covered by fast movements in the left colon (P = .001).

Conclusion & Inferences

Oxycodone treatment impaired colonic motility, manifested as increased transit time, specifically decreased long fast antegrade movements, and addition of naloxegol improved motility dynamics. In humans, the increased transit time during opioid treatment is caused by a decrease in long fast movements rather than uncoordinated peristalsis.
Precision medicine, agriculture, and genome editing: science and ethics
Authors: Moscoso Carlos G. , Potz Kelly R. , Tan Shaoyuan , Jacobson Pamala A. , Berger Kavita M. , Steer Clifford J.
Published: November 2019

The era of precision medicine has generated advances in various fields of science and medicine with the potential for a paradigm shift in healthcare delivery that will ultimately lead to an individualized approach to medicine. Such timely topics were explored in 2018 at a workshop held at the Third International Conference on One Medicine One Science (iCOMOS), in Minneapolis, Minnesota. A broad range of scientists and regulatory experts provided detailed insights into the challenges and opportunities associated with precision medicine and gene editing. There was a general consensus that advances in studying the genomic traits driving differential pharmacogenomics will undoubtedly enhance individualized treatments for a wide variety of diseases. Ethical considerations, societal implications, approaches for prioritizing safe and secure use of treatment modalities, and the advent of high‐throughput computing and analysis of large, complex datasets were discussed. Large biobanks, such as the All of Us Research Program and the Veterans Affairs Million Veterans Program, can aid studies of various conditions in massive cohorts of patients. As the applications of precision medicine continue to mature, the full potential and promise of these individualized approaches will continue to yield important advances in transplant medicine, oncology, public health, agriculture, pharmacology, and bioinformatics.
Identification and Sensitivity Analysis of Contagion Effects in Randomized Placebo-Controlled Trials
Authors: Imai Kosuke , Jiang Zhichao
Published: November 2019

In social science research, interference between units is the rule rather than the exception. Contagion represents one key causal mechanism of such spillover effects, where one's treatment affects the outcome of another individual indirectly by changing the treated unit's own outcome. Alternatively, the treatment of one individual can affect the outcome of another person through other mechanisms. We consider the identification and sensitivity analysis of contagion effects. We analyse a randomized placebo-controlled trial of the get out the vote campaign, in which canvassers were sent to randomly selected households with two registered voters but encouraged only one voter within each household to turn out in an upcoming election. To address the problem of non-compliance, the experiment includes a placebo arm, in which canvassers encourage voters to recycle. We show how to identify and estimate the average contagion and direct effects by decomposing the average spillover effect. Our analysis examines whether canvassing increases the turnout of a non-contacted voter by altering the vote intention of a contacted voter or through other mechanisms. To address the potential violation of key identification assumptions, we propose non-parametric and parametric sensitivity analyses. We find robust contagion effects among some households.
Networked Geographies of Digital Contention in Post‐Financial Crisis Ireland
Authors: Nic Lochlainn Maedhbh
Published: November 2019

The language of networks has become a common conceptual framework for describing contemporary, digitally‐engaged social movements. In this paper I address the subject of digital contention from a geographical perspective, using network analysis and qualitative data to explore the networked digital contention of anti‐water charges community groups in Dublin, Ireland. Focusing thematically on network fragmentation, I use places and practices as frames to understand this situated case study and make two main points. First, social media networks are constituted through choices by individuals about how to articulate place relationally to fulfil specific political and social objectives. Second, contextual and historical components of specific places can provide an explanatory mechanism for understanding points of concentration and fragmentation in the network. Network analysis is useful for visualising and interpreting digital contention but augmenting network analysis with qualitative methods of data collection allows for deeper understanding of the geographical nuances of digital contention.
Undercover Boss's Travels: Comparing the US and UK Reality Shows
Authors: Gershon Ilana
Published: November 2019

Comparing different versions of Undercover Boss reveals how an assemblage of TV producers, camera crews, businesses, and broadcasters choose to portray corporate hierarchies during the financial crisis of 2008 when corporations seemed like especially vulnerable forms of social organization for workers to rely upon. This article approaches the same show done in two different countries as a natural experiment that can reveal national differences through a textual comparison. The US show relies upon a sentimental imagination such that knowledge of the other is based on an emotional connection to the past. The UK show relies upon an organizational imagination in which the structural roles one plays in a company shape what one knows of how the company functions. Each version portrays distinctive approaches to three issues: (1) what can be known about people as social actors; (2) what is portrayed as ethical or appropriate workplace relationships; and (3) what kinds of tacit critiques of contemporary capitalism are possible.
Exploration of a Ca1−x(NaCe)x/2Bi4Ti3.98(WNb)0.01O15 ceramic intermediate phase by temperature-dependent spectroscopic ellipsometry and Raman scattering
Authors: Ding Qiong , Xu Liping , Zhang Jinzhong , Jiang Kai , Hu Zhigao , Zhou Zhiyong , Dong Xianlin , Chu Junhao
Published: November 2019

Different doping concentrations of Ca1−x(NaCe)x/2Bi4Ti3.98(WNb)0.01O15 (x=0, 3%, 4%, 5%, and 6%) were prepared by a traditional solid state reaction method. The effects of doping on the crystal structure, dielectric constant, electronic transitions, and lattice dynamics of doped CaBi4Ti4O15 were investigated by x-ray diffraction, temperature-dependent spectroscopic ellipsometry, and Raman scattering. The results showed that, when x<4%, the substitution of Na [rNa=0.95 Å with a coordination number (CN) = 6] is dominant, and the crystal structure symmetry is weakened. When x>4%, the substitution of Ce (rCe=1.01 Å, CN=6) is dominant, and the crystal structure symmetry begins to increase. As the doping concentration increases, the optical bandgap initially increases and then decreases, which is consistent with the evolution of the structural symmetry. Finally, evidence of the existence of an intermediate phase transformation of CaBi4Ti4O15-based ceramics is extracted by analyzing the thermal evolution of the electronic transitions and Raman modes. Therefore, spectroscopic ellipsometry and Raman spectroscopy can be used to probe intermediate phase transformations in ferroelectrics.
Effect of the plasma confinement on properties of a-C:H:SiOx films grown by plasma enhanced chemical vapor deposition
Authors: Grenadyorov Alexander S. , Solovyev Аndrey А. , Oskomov Konstantin V. , Oskirko Vladimir O.
Published: November 2019

The properties of SiOx doped amorphous hydrogenated carbon (a-C:H:SiOx) films greatly depend on the deposition parameters, in particular, on the ion bombardment intensity during the film growth. In this work, a magnetic field created by an external magnetic coil was used for plasma confinement and control of the ion bombardment during the process of plasma enhanced chemical vapor deposition of a-C:H:SiOx films. The structure, surface morphology, and mechanical properties of the obtained films were studied using Raman spectroscopy, atomic force microscopy, and nanoindentation, respectively. This work shows that the increase in the magnetic field allows better confinement of the plasma and increased the density of the ion current on the substrate. It is shown that there is an optimal value of the magnetic field at which films with the best mechanical characteristics are formed. Higher magnetic field values lead to excessive heating of the substrate by the bombarded ions and graphitization of the film carbon matrix. Under optimum conditions, deposition of an a-C:H:SiOx film on an AISI 321 stainless steel substrate allowed increasing the hardness and plasticity index of its surface twice and its plastic deformation resistance by nine times. At the same time, the wear rate and the friction coefficient decreased by 25 and 5.5 times, respectively.
Efficient methodology for estimation of metal effective work function, interface trap, and fixed oxide charges in metal-oxide-semiconductor capacitors with dual layer high-κ/SiO2 dielectric
Authors: Samanta Piyas
Published: November 2019

A capacitance-voltage (C–V) based efficient methodology is demonstrated for precise estimation of process-induced various fixed charge distributions in the dielectric layer, interface trapped charges at the silicon/oxide interface, and the effective work function (EWF) of the metal gate on double layer high-κ/silicon dioxide (SiO2) stack in metal-oxide-semiconductor (MOS) capacitors. The present technique takes care of the variation of the work function of the silicon substrate either due to wafer-to-wafer variation or nonuniformity of the doping level throughout the entire wafer. The analysis is verified with experimentally obtained high-frequency C–V results by varying only the physical thickness tHfO2 of the hafnium oxide (HfO2) dielectric layer on an interfacial SiO2 film of a fixed thickness tox in tantalum nitride (TaN)/HfO2/SiO2/p-Si MOS diodes. A value of 4.5 eV was obtained for EWF of physical vapor deposited TaN on HfO2. Furthermore, the calculations indicate the presence of a significant amount of positive bulk charges in the high-κ layer, in addition to interface trapped positive charges Qit at the Si/SiO2 interface and negative effective charges at both the high-κ/SiO2 and Si/SiO2 interfaces.
Temperature dependence of dielectric function spectra and interband optical transitions in layered TlInS2
Authors: Shim Yong-Gu , Tashiro Ryo , Wakita Kazuki , Mamedov Nazim
Published: November 2019

The temperature behavior of the dielectric function spectra and related interband optical transitions in layered TlInS2 with a structural ferroelectric phase transition via an intermediate incommensurate phase has been studied over the temperature range of 80–400 K by using spectroscopic ellipsometry in the photon energy region from 1.5 to 4.2 eV. Both (100) and (001) surfaces of TlInS2 have been examined, and the collected ellipsometric data have allowed retrieving diagonal components of the dielectric function tensor. Standard critical point analysis of the retrieved components shows that energy and broadening of the interband optical transitions subsequently experience remarkable changes upon reaching the points of phase transitions. The obtained results provide a better insight into optical properties and the electronic structure of incommensurate semiconductors-ferroelectrics.
Reaction mechanism of N atoms interaction with low-k organosilicate glass films: Dynamic density functional theory study
Authors: Voronina Ekaterina N. , Mankelevich Yuri A. , Rakhimova Tatyana V. , Lopaev Dmitry V.
Published: November 2019

Damage of porous organosilicate glass films with low dielectric constants (low-k films) in plasma processing is a critical problem for modern microelectronics. For this problem, understanding and revealing of basic reactions for radical (e.g., O, F, and N atoms) interactions with low-k films are of importance. In this study, reactions of initial (Si‒CH3) and appeared (Si‒CHxNy) surface groups with incident N atoms in the ground and excited metastable states were simulated systematically by the dynamic density functional theory (DFT) method. On the basis of a large amount of calculated vibrational modes of various N-containing groups and reaction trajectories, the most important Si‒CHxNy groups for the explanation of obtained experimental data were selected and the most probable reaction pathways were found and described in detail. The proposed reaction mechanism revealed by DFT modeling is used to analyze and to explain the measured FTIR spectra changes with N atom doses and temperatures of porous low-k films.
Designing a waveguide to transmit sound to a dolphin in a functional magnetic response imaging machine
Authors: Foster Jawanza K. , Buck John R.
Published: November 2019

Functional Magnetic Resonance Imaging (fMRI) offers great opportunities to learn how a dolphin’s brain processes acoustic echolocation and communication signals. Delivering sound to an animal in a fMRI requires a sound delivery system with no ferrous metal. This talk proposes an approach that generates sound far from the fMRI magnet and then conducts the sound through a waveguide to the dolphin roughly 10 m away. The waveguide functions at two frequency ranges are 80 kHz for echolocation signals and 10 kHz to 20 kHz for communication signals. This approach has two challenges: will there be enough energy for the dolphin to hear the acoustic signals and will the received signal be distorted? The waveguide loses energy due to the radiation impedance around the hydrophone, absorption and friction, and the impedance mismatch between the waveguide and the dolphin. Filling the waveguide with water limits the transmission loss through the waveguide. The waveguide radius will be chosen to limit the number of trapped modes, minimizing distortion due to dispersion. [Funded by the ONR MURI program.]
Acoustical ocean ecology in the era of the robot revolution
Authors: Benoit-Bird Kelly J.
Published: November 2019

Over the past decade, the field of oceanography has experienced a robotic revolution. A proliferation of autonomous surface and underwater platforms is providing new ways to obtain environmental, chemical, and biological data. Bioacoustical oceanographic sensors are increasingly being added to the payload of these platforms to provide increased spatial and temporal coverage as well as access to unexplored areas. Integrating relatively large, high power draw sensors like scientific echosounders is a challenge, however, and each platform type and size have specific tradeoffs with respect to these payloads. I will present case studies employing echsounders from autonomous surface vessels to study the deep scattering layer, a deep-diving, short endurance autonomous underwater vehicle for examining bathypelagic squid, and a moderate endurance underwater glider for examining the relationship between forage species and their environment. These studies illustrate the challenges of integration of echsosounder payloads into platforms as well as the opportunities of robotic approaches for bioacoustical oceanography. Finally, a recent experiment integrating nine robotic platforms and a cabled observatory will highlight how the integration of various sensor technologies and platforms can be used to study dynamic biological processes like diel vertical migration in the ocean.
Operational ocean acoustic tomography
Authors: Laferriere Alison B. , Lermusiaux Pierre F. , Dorfman Yevgeniy , Goldsmith Michael , Heaney Kevin D. , Kofford Aaron
Published: November 2019

The estimation of sound speed fields using ocean acoustic tomography (OAT) in operational systems is limited because user intensive post processing and manual association of arrivals with ray paths are required. Furthermore, inversion techniques typically rely on CTD casts or historical data to create reference sound speed profiles and Gaussian statistical characterizations for the inversion, which may be either unavailable, out of date, or too approximate due to the intermittent ocean dynamics. A method is presented for real-time implementation of OAT, including the tracking of acoustic arrivals, model-data association of ray paths to arrivals (ray identification), and tomographic inversions. One- and two-dimensional tomographic inversions for sound speed fields are performed using stochastic ensemble forecasts of the sound speed field generated via the Multidisciplinary Simulation, Estimation, and Assimilation Systems (MSEAS) Primitive-Equation probabilistic ocean modeling system. The method is demonstrated on simulated and real data obtained from moored tomographic sources and receivers, deployed in deep water 100 km South of Nantucket, MA. [This research was developed with funding from the Defense Advanced Research Projects Agency (DARPA). ]
Controlled drug delivery and release in brain tumors with focused ultrasound
Authors: Arvanitis Costas , Guo Yutong , Kim Chulyong
Published: November 2019

Several passive and active strategies based on different nanoparticle (NP) formulations have been proposed for improving drug delivery in brain tumors. Despite improved NP designs, drug accumulation in brain tumors remains very low. In this talk, we will present two different strategies to improve the penetration of therapeutic agents in brain tumors. The first uses transcranial focused ultrasound (FUS) in combination with microbubbles to overcome the vascular barriers of brain tumors. Our findings indicate that ultrasonically actuated microbubbles can increase the interstitial convective transport (Penon-FUS ≈ 0.1 to PeFUS ≈ 20), in addition to alleviating the vascular barriers, and improve the extravasation of fluorescently labeled NPs (∼40 nm in diameter) in healthy mice brain and mice brain tumor models. The second strategy employs transcranial MR guided focused ultrasound (MRgFUS) combined with low temperature sensitive liposomes loaded with doxorubicin (LTS-Dox ∼ 100 nm in diameter). Using an optimized MRgFUS system and closed-loop methods for controlled transcranial hyperthermia (∼10 min), we were able to significantly increase doxorubicin uptake in LTS-Dox + FUS group as compared to LTS-Dox and free Dox groups (<0.01) in mice brain tumor model. Our results demonstrate that these therapeutic strategies provide unique opportunities to improve the delivery of NPs and their cargo in the brain and brain tumor microenvironment.
Bayesian statistical dose-response models
Authors: Lee Jasme , Rathsam Jonathan , Wilson Alyson G.
Published: November 2019

In the coming years, NASA will collect nationally representative data to support efforts to develop international standards for permissible noise from commercial supersonic flight over land. The data will elucidate the relationship between sonic boom noise exposure and community response. This presentation introduces several Bayesian statistical models and a method to calculate a summary dose-response curve. Additionally, the statistical models illuminate the trade-off between sample size and precision of estimated quantities such as percent highly annoyed. This trade-off will inform sample size decisions for future community surveys. All models are fit to data from a recent NASA community response test, the Quiet Supersonic Flights 2018 (QSF18) test.
The effect of acoustically driven fluid motion on boundary-induced pattern formation
Authors: Thompson Charles , Chandra Kavitha , Norude Flore
Published: November 2019

This work examines the process of boundary-induced pattern formation in reaction-diffusion systems. The influence of acoustically induced time-averaged advection that results from the gradient of the Reynolds stress is of particular interest. The presentation will focus on the role that boundary vibration and unsteady fluid motion have on manipulating chemical concentration at the microscale.
Acoustic versus articulatory accounts of asymmetries in vowel perception
Authors: Masapollo Matthew
Published: November 2019

Most research on cross-language speech perception has concentrated on how and when the discrimination and categorization of speech sounds change with specific linguistic experience. It has become increasingly clear, however, that there are also universal biases in place early in development that guide and constrain how perceivers from diverse linguistic backgrounds decode the speech signal. In the domain of vowel perception, it is now known that perceivers (both adult and infant) are universally biased toward articulatorily and acoustically extreme vowels. This generic vowel bias is often demonstrated in discrimination tasks as a directional asymmetry: perceivers perform better when discriminating changes from less to more peripheral vowels compared to the reverse. I will discuss evidence indicating that the processes underlying these asymmetries operate on articulatory information, rather than on acoustic information per se. I will begin with findings from cross-language experiments with adults indicating that asymmetries occur with vowels presented in either the auditory or the visual modality, regardless of native language. I will then present findings indicating that analogous asymmetries in visual perception emerge using schematic non-speech visual analogs of vowels, but only if the optical stimuli depict both lip-motion and configural information, consistent with an articulatory account of asymmetries.
Experimental investigation of acoustic channel reciprocity in shallow water
Authors: Liu Zhiqiang , Emokpae Lloyd , Schindall Jeffrey , Edelmann Geoffrey F.
Published: November 2019

Channel reciprocity is recognized as one of the most fundamental properties of underwater acoustic propagation. The theoretical proof of channel reciprocity assumes that the ocean environment is static during the course of acoustic propagation. Since this assumption might not be valid for the case of shallow-water acoustic propagation, a question to be raised is: does channel reciprocity remain true in shallow water? A sea-going experiment was recently conducted to study the shallow-water channel reciprocity. In the experiment, two custom-built software-defined acoustic modems were used to probe their shared channel from two opposite directions. The channel reciprocity was examined by comparing the two probed channels directly. The probing signals and handshaking protocols were judiciously designed to minimize the effects of channel dynamics under the constraint of half-duplex acoustic modems. This paper will provide the details of this sea experiment (including its design, setups and execution) and report interesting findings. [Work supported by US Office of Naval Research.]
Impact of channel fluctuations on channel estimation errors in underwater acoustic communications
Authors: Guo Zheng , Song Aijun
Published: November 2019

Channel estimation is critical to achieve high data rate acoustic communications in the ocean. Channel estimates are often utilized to address the distortions induced by multipath propagation in various communication receivers. Therefore, accurate channel estimation is often the prerequisite for reliable coherent acoustic communications. Many efforts have been devoted to either characterizing the acoustic channel or developing high-performance channel estimation algorithms. However, limited work has been directed to investigate effect of channel fluctuations on estimation performance. Here we seek to quantify the impact of channel fluctuations on least squares channel estimators. A new metric, channel variation ratio, is used to describe the rate of fluctuations in the acoustic impulse responses. We investigate the relationship between the mean squared error (MSE) of the channel estimates and the channel variation ratio. We show the new metric can be used to predict channel estimation MSE for least squares channel estimators. Numeric results also show that there exists an optimal channel length with the minimum estimation error for fluctuating acoustic channels. Both computer simulations and experimental data have been used to validate the findings. [Work supported by the National Science Foundation CNS# 1704076.]
Iterative multi-channel FH-MFSK reception in underwater acoustic communication
Authors: Sun Dajun , Hong Xiaoping , Cui Hongyu , Liu Lu
Published: November 2019

With the challenges of long multipath, large Doppler spreads, high ambient noise and rapid phase fluctuation in mobile shallow underwater acoustic (UWA) channels, design of robust UWA communication system should be carefully considered. Aiming at this topic, a convolutionally encoded noncoherent frequency-hopped M-ary frequency-shift-keyed (FH-MFSK) modulation scheme with a novel iterative multi-channel reception is proposed. To obtain the reception suitable for noncoherent MFSK, the ideas of iterative multi-channel demodulation and decoding are combined and extended. A modified multi-channel soft input soft output (SISO) demodulator based on maximum a posterior (MAP) criterion is derived, and substantial gains of several decibels in power efficiency are achieved. Extra gain can be obtained by utilizing time diversity with long multi-path delay. Simulation shows that a noncoherent receiver equipped with 5 arrays obtains around 5.5 dB gain over single noniterative receiver. A shallow water field testing at Songhua Lake with 500 m distance verifies the robustness and usability of the proposed receiver.
Locating calling mammals with signal times amongst shadows and black holes in two-dimensional models
Authors: Spiesberger John
Published: November 2019

Calling mammals and other objects were commonly located during the last century with two-dimensional (2-D) models from measurements of a signal’s Time Differences of Arrival (TDOA) when the objects are not on the 2-D surface. The common method for locating signals with 2-D models takes signal speed as constant and location is derived by intersecting hyperbolas. However, when correct locations are required, the speed used to derive location must depend on geodesic distance along the 2-D model surface between the object and instrument. For example, when this distance is zero, the speed needed for correct location must also be zero. The dimension reduction from three to two introduces large errors in 2-D models both near and far from the instruments unless variable speeds induced by the dimensional reduction are accounted for. Consequently, methods are derived for generating extremely reliable confidence intervals for locations in 2-D models and identifying regions of the 2-D model where a 3-D model is needed. Because speeds needed for correct location are spatially inhomogeneous in the extreme, isodiachrons emerge as a natural geometry for interpreting location. These issues are caused by choice of coordinates. Similar phenomena occur when coordinate transformations reapplied in relativity [Preprint arxiv:1811.05539 (2018)].
Measurements and impulse pattern formulation (IPF) model of phase transitions in free-reed wind instruments
Authors: Bader Rolf , Linke Simon , Mores Robert
Published: November 2019

Free-reed wind instruments have a free reed attached to a tube, and are a unique instrument of Laos, Thailand, China, or Japan. Three examples, a 5-pipe hulusheng from Yunnan, China and two Laotian instruments, a 6-pipe Hmong and a 14-pipe Lao khaen are compared in terms of their construction and acoustic properties. With normal playing pressure the pipes only sound when a hole in the pipe is closed. Then, the pitch is determined by the pipe length. When the holes are open the pipes do not sound. Still with low blowing pressure some pipes sound near the frequency of the free reed. A sudden phase transition from reed to pipe frequency happens at a certain blowing pressure. On the contrary, the bordun pipe cannot be muted and produces two pitches with a one-hole fingering. Using the Impulse Pattern Formulation (IPF), which assumes the instrument to work with traveling pressure impulses through the pipes which are reflected, damped and act back on the reed again, the fundamental behaviour of free-reed instruments is modelled.
Evaluation of sonic booms measured in D-SEND#2 flight test
Authors: Naka Yusuke , Kanamori Masashi , Ishikawa Hiroaki , Makino Yoshikazu
Published: November 2019

Japan Aerospace Exploration Agency (JAXA) conducted a supersonic flight test named D-SEND#2 to validate its low-boom technology. In the D-SEND#2 test, sonic booms generated by a scaled, unmanned test vehicle designed by applying JAXA’s low-boom concept were measured on and above the ground. Due to a unique flight profile, various types of sonic booms, including N-type and shaped waveforms, generated under different flight conditions were obtained. Although the measurements aloft were intended to avoid or weaken the effects of atmospheric turbulence near the ground on the sonic boom signatures, distortions of waveforms were observed even in the sonic boom data measured above the ground. Noise metrics are calculated for the sonic booms measured at different altitudes, and the effects of the atmospheric turbulence are evaluated. The measurements are also compared with numerical predictions.
Ground effects on sonic boom reflection
Authors: Emmanuelli Ariane , Lechat Thomas , Dragna Didier , Ollivier Sébastien
Published: November 2019

Impact of a real terrain on the sonic boom signature at the ground has been little studied in the literature. In the current prediction schemes, a flat and perfectly reflecting ground is usually assumed and the reflected boom is obtained by multiplying the incident boom by a constant factor. In this paper, the effects of a non-flat and absorbing ground are investigated. For this, a numerical study is conducted. The 2-D Euler equations are solved in curvilinear coordinates using high-order finite difference schemes. Signatures of the incident boom typical of a classical N-wave and of a low boom are considered. The variability on the waveform at the ground induced by the terrain irregularities is studied for different characteristic length scales of the terrain.
Infrasound observations from the 2019 Tornado Season
Authors: Elbing Brian R. , Petrin Christopher , Van Den Broeke Matthew S. , Green Erik
Published: November 2019

Tornado producing storms have been observed to emit infrasound (sound at frequencies below human hearing) up to 2 h before tornadogenesis. Weak atmospheric attenuation at these frequencies allows for long-range detection. Hence, passive infrasonic monitoring could be a method for long-range studying of tornadogenesis as well as tornado characterization. Identifying the fluid mechanism(s) that produce the infrasound production is critical to enable such capabilities, but currently there are insufficient observations to test potential mechanisms. The 2019 tornado season has been extreme, with over 1000 tornadoes in the United States. This includes numerous severe storms within the range of an infrasound array that was deployed at Oklahoma State University to monitor severe storm infrasound. The current work presents infrasound and, when possible, radar analysis of severe storms during 2019. [Work supported by NSF Grant Nos. 1539070 and NOAA NA18OAR4590307.]