bluuebunny/crossref_metadata_2025 huggingface dataset:
Entropic restrictions control the electric conductance of superprotonic ionic solids
Authors: Santamaría-Holek Iván , Ledesma-Durán Aldo , Hernández S. I. , García-Alcántara C. , Andrio Andreu , Compañ Vicente
Published: November 2019

The change in entropic restrictions in a superprotonic transition controls the increase of the ionic conductance in ionic solids.
Synthetic ratiometric fluorescent probes for detection of ions
Authors: Park Sang-Hyun , Kwon Nahyun , Lee Jee-Hyeon , Yoon Juyoung , Shin Injae
Published: November 2019

Synthetic ratiometric fluorescent probes are useful to detect metal cations and anions.
Photosynthetic response mechanisms in typical C3 and C4 plants upon La2O3 nanoparticle exposure
Authors: Liu Yinglin , Yue Le , Wang Chuanxi , Zhu Xiaoshan , Wang Zhenyu , Xing Baoshan
Published: November 2019

Herein, the photosynthesis of C3 and C4 plants was found to display different regulatory strategies under exposure to La2O3 NPs.
Coupled morphological and structural evolution of δ-MnO2 to α-MnO2 through multistage oriented assembly processes: the role of Mn(iii)
Authors: Liang Xinran , Post Jeffrey E. , Lanson Bruno , Wang Xiaoming , Zhu Mengqiang , Liu Fan , Tan Wenfeng , Feng Xionghan , Zhu Guomin , Zhang Xin , De Yoreo James. J.
Published: November 2019

δ-MnO2 transforms to α-MnO2 through a multistage oriented assembly process which is induced by Mn(iii).
Novel heterogeneous ruthenium racemization catalyst for dynamic kinetic resolution of chiral aliphatic amines
Authors: Adriaensen Koen , Vercammen Jannick , Van Goethem Cédric , Eyley Samuel , Vankelecom Ivo , Thielemans Wim , De Vos Dirk
Published: November 2019

Only few dynamic kinetic resolution (DKR) systems are known for chiral aliphatic amines due to the difficult racemization of these amines.
Carotenoids, chlorophylls and phycocyanin from Spirulina: supercritical CO2 and water extraction methods for added value products cascade
Authors: Marzorati Stefania , Schievano Andrea , Idà Antonio , Verotta Luisella
Published: November 2019

This work investigates a green approach for an integrated extraction-chain of added-value compounds from Spirulina.
Modular design of a trap-and-atomizer device with a gold absorber for selenium collection after hydride generation
Authors: Machado Ignacio , Vaněk Dominik , Musil Stanislav , Pistón Mariela , Dědina Jiří , Kratzer Jan
Published: November 2019

A novel device serving to trap hydrides and to volatilize the analyte to be detected by atomic absorption spectrometry, a modular trap-and-atomizer device, was invented to allow a simple replacement of the inlet arm which serves as the trap.
Triple-pulse LIBS: laser-induced breakdown spectroscopy signal enhancement by combination of pre-ablation and re-heating laser pulses
Authors: Prochazka David , Pořízka Pavel , Novotný Jan , Hrdlička Aleš , Novotný Karel , Šperka Petr , Kaiser Jozef
Published: November 2019

The goal of this work is to examine the effect of a third additional laser pulse on orthogonal double-pulse laser-induced breakdown spectroscopy (DP LIBS).
Contactless sensing of liquid marbles for detection, characterisation & computing
Authors: Draper Thomas C. , Phillips Neil , Weerasekera Roshan , Mayne Richard , Fullarton Claire , de Lacy Costello Ben P. J. , Adamatzky Andrew
Published: November 2019

New liquid marble sensor exploits impedance to detect presence of liquid marbles, whilst also providing characterisation information.
The direct C–H alkenylation of quinolineN-oxides as a suitable strategy for the synthesis of promising antiparasitic drugs
Authors: Kouznetsov Vladimir V. , Vargas Méndez Leonor Y. , Puerto Galvis Carlos E. , Ortiz Villamizar Marlyn C.
Published: November 2019

This review highlights the direct C–H alkenylation of quinolineN-oxides covering the metal-free and transition-metal catalysed protocols, and the regioselectivity during the synthesis of antiparasitic drugs based on quinoline scaffold.
Correction: Empowering mechanochemistry with multi-mechanophore polymer architectures
Authors: Bowser Brandon H. , Craig Stephen L.
Published: November 2019

Correction for ‘Empowering mechanochemistry with multi-mechanophore polymer architectures’ by Brandon H. Bowser et al., Polym. Chem., 2018, 9, 3583–3593.
Ring-opening metathesis polymerization of a strained stilbene-based macrocyclic monomer
Authors: Lynde Brock E. , Maust Ruth L. , Li Penghao , Lee Daniel C. , Jasti Ramesh , Boydston Andrew J.
Published: November 2019

We report the synthesis of a new class of strained macrocycle that performs well in ring-opening metathesis polymerization (ROMP).
Branched polyethyleneimine-assisted 3-carboxybenzoboroxole improved Wulff-type boronic acid functionalized magnetic nanoparticles for the specific capture of cis-diol-containing flavonoids under neutral conditions
Authors: Li Daojin , Liu Zheyao , Song Rumeng , Yang Wenliu , Zhai Simeng , Wang Wenhui
Published: November 2019

Flavonoids have shown a variety of biological activities such as antimicrobial, antibacterial, antifungal, antiviral, antiinflammatory, antitumor, antiatherogenic, and antihyperglycemic activities.
Gravimetric analysis of the autocatalytic growth of copper microparticles in aqueous solution
Authors: Byun Jinuk , Kim Kwang Hawn , Kim Byung Keun , Chang Ji Woong , Cho Sung Ki , Kim Jae Jeong
Published: November 2019

The growth kinetics of copper microparticles was analysed by using the gravimetric method.
A light emitter based on practicable and mass-producible polycrystalline graphene patterned directly on silicon substrates from a solid-state carbon source
Authors: Nakagawa Kenta , Takahashi Hidenori , Shimura Yui , Maki Hideyuki
Published: November 2019

We developed a procedure for direct patterning graphene with arbitrary position, size, and shape on Si from a solid-state carbon source without dry etching. Our light emitting devices perform on a par with those based on high crystallinity graphene.
Diffusiophoresis of active colloids in viscoelastic media
Authors: Saad Shabab , Natale Giovanniantonio
Published: November 2019

Self-diffusiophoresis of synthetic Janus (Si/Pt) microspheres in the presence of hydrogen peroxide in complex environments is here investigated.
Comparison of different zinc precursors for the construction of zeolitic imidazolate framework-8 artificial shells on living cells
Authors: Chen Wei , Kong Shu , Lu Meng , Chen Fangming , Cai Wen , Du Liping , Wang Jian , Wu Chunsheng
Published: November 2019

The robust zeolitic imidazolate framework-8 (ZIF-8) shell was formed on the living cells by anin situprecipitation method. Compared with zinc nitrate and zinc acetate, ZIF-8 formed from zinc sulfate lead to a higher percentage of cell death.
Toward a systems approach to cytochrome P450 ensemble: interactions of CYP2E1 with other P450 species and their impact on CYP1A2
Authors: Davydova Nadezhda Y. , Dangi Bikash , Maldonado Marc A. , Vavilov Nikita E. , Zgoda Victor G. , Davydov Dmitri R.
Published: November 2019

In this study, we investigate the ability of ethanol-inducible CYP2E1 to interact with other cytochrome P450 species and affect the metabolism of their substrates. As a model system, we used CYP2E1-enriched human liver microsomes (HLM) obtained by the incorporation of purified CYP2E1. Using a technique based on homo-FRET in oligomers of CYP2E1 labeled with BODIPY 577/618 maleimide we demonstrated that the interactions of CYP2E1 with HLM result in the formation of its mixed oligomers with other P450 species present in the microsomal membrane. Incorporation of CYP2E1 results in a multifold increase in the rate of metabolism of CYP2E1-specific substrates p-Nitrophenol and Chlorzaxozone. The rate of their oxidation remains proportional to the amount of incorporated CYP2E1 up to the content of 0.3–0.4 nmol/mg protein (or ∼50% CYP2E1 in the P450 pool). The incorporated CYP2E1 becomes a fully functional member of the P450 ensemble and do not exhibit any detectable functional differences with the endogenous CYP2E1. Enrichment of HLM with CYP2E1 results in pronounced changes in the metabolism of 7-ethoxy-4-cyanocoumarin (CEC), the substrate of CYP2C19 and CYP1A2 suggesting an increase in the involvement of the latter in its metabolism. This effect goes together with an augmentation of the rate of dealkylation of CYP1A2-specific substrate 7-ethoxyresorufin. Furthermore, probing the interactions of CYP2E1 with model microsomes containing individual P450 enzymes we found that CYP2E1 efficiently interacts with CYP1A2, but lacks any ability to form complexes with CYP2C19. This finding goes inline with CYP2E1-induced redirection of the main route of CEC metabolism from CYP2C19 to CYP1A2.
Radio relic and the diffuse emission trail discovered in low-mass galaxy cluster Abell 1697
Authors: Paul Surajit , Salunkhe Sameer , Sonkamble Satish , Gupta Prateek , Mroczkowski Tony , Raychaudhury Somak
Published: November 2019

We report the discovery of a putative radio relic, 830 kpc in length, and found towards the outskirts of galaxy cluster Abell 1697 (z = 0.181), using the LOFAR Two Meter Sky Survey at 144 MHz. An X-ray-inferred mass of M500X-ray = 2.9−0.7+0.8 × 1014 M⊙ places Abell 1697 among the least massive relic hosts. The relic is also detected at 325 MHz in the Westerbork Northern Sky Survey and at 1.4 GHz in the NRAO VLA Sky Survey, with an average spectral index of α(144, 325, 1400 MHz) = − 0.98 ± 0.01, and magnetic field of Beq ∼ 0.6 μG. This relic, located in the north-east periphery of the cluster, is 300 kpc wide, exhibits a gradual spectral steepening across the width (α144 MHz1.4 GHz(inj) = −0.70 ± 0.11 to α144 MHz1.4 GHz(edge) = −1.19 ± 0.15), as well as indications of a co-spatial X-ray (ROSAT) shock and the radio relic emission. The radio power of the relic is P1.4 GHz = 8.5 ± 1.1 × 1023 W Hz−1, which is found to be in good agreement with the expected empirical correlation between the radio power and largest linear size of relics. The relic is trailed by extended (790 × 550 kpc) diffuse radio emission towards the cluster centre, which is likely an ultra-steep spectrum (α144 MHz1.4 GHz < −1.84) radio source. This structure is also found to be older by at least 190 Myr, has a very low surface brightness of 0.3 μJy arcsec−2 and magnetic field Beq ∼ 0.8 μG, similar to that of a radio phoenix. Finally, we discuss the possible mechanisms responsible for the relic and the trailing diffuse radio emission, invoking re-acceleration due to wake turbulence, as well as the revival of fossil electrons in the remnant radio lobes of active galactic nuclei by the cluster merger shocks.
Nutrition and health claims in Europe: oils & fats related claims, regulatory and labeling challenges
Authors: Bucchini Luca
Published: November 2019

In the European Union, fats and oils in foods are regulated by laws mainly set at the Union level. EU rules on nutrition and health claims are particularly relevant for some fatty acids. Contrary to structure-function claims in the US, in the EU, such claims have to be authorized before use; in the case of omega-3, along with a nutrition claim, a remarkable number of health claims have been authorised based on the essentiality of such fatty acids. Claims related to environmental, social or ethical concerns are not regulated in detail at the EU level. While claims are voluntary information, mandatory rules on labelling also apply to fatty acids, and sometimes create challenges for food businesses. Another piece of legislation, the novel food regulation, is important for new sources of oils and fats. Its scope includes determining the novel food status of foods, and, if required, submitting an application in order to obtain authorisation. Several sources of fatty acids have been authorized as novel foods. Benefits of a novel food application include legal certainty and protection of data, while costs and particularly the length of the process are the main barriers. An assessment of novel food status should also concern new technologies, such as new delivery mechanisms. While several provisions of EU law concern oils and fats, a 2019 regulation not only imposes a 2 g limit (per 100 g of fat) for trans fats not naturally occurring in animal fats, but also creates an obligation to transfer information in the supply chain.
Platelet Function Changes during Neonatal Cardiopulmonary Bypass Surgery: Mechanistic Basis and Lack of Correlation with Excessive Bleeding
Authors: Zwifelhofer Nicole M. J. , Bercovitz Rachel S. , Cole Regina , Yan Ke , Simpson Pippa M. , Moroi Alyssa , Newman Peter J. , Niebler Robert A. , Scott John P. , Stuth Eckehard A. D. , Woods Ronald K. , Benson D. Woodrow , Newman Debra K.
Published: November 2019

Thrombocytopenia and platelet dysfunction induced by extracorporeal blood circulation are thought to contribute to postsurgical bleeding complications in neonates undergoing cardiac surgery with cardiopulmonary bypass (CPB). In this study, we examined how changes in platelet function relate to changes in platelet count and to excessive bleeding in neonatal CPB surgery. Platelet counts and platelet P-selectin exposure in response to agonist stimulation were measured at four times before, during, and after CPB surgery in neonates with normal versus excessive levels of postsurgical bleeding. Relative to baseline, platelet counts were reduced in patients while on CPB, as was platelet activation by the thromboxane A2 analog U46619, thrombin receptor activating peptide (TRAP), and collagen-related peptide (CRP). Platelet activation by adenosine diphosphate (ADP) was instead reduced after platelet transfusion. We provide evidence that thrombocytopenia is a likely contributor to CPB-associated defects in platelet responsiveness to U46619 and TRAP, CPB-induced collagen receptor downregulation likely contributes to defective platelet responsiveness to CRP, and platelet transfusion may contribute to defective platelet responses to ADP. Platelet transfusion restored to baseline levels platelet counts and responsiveness to all agonists except ADP but did not prevent excessive bleeding in all patients. We conclude that platelet count and function defects are characteristic of neonatal CPB surgery and that platelet transfusion corrects these defects. However, since CPB-associated coagulopathy is multifactorial, platelet transfusion alone is insufficient to treat bleeding events in all patients. Therefore, platelet transfusion must be combined with treatment of other factors that contribute to the coagulopathy to prevent excessive bleeding.
An Unusual Combination of Three Rare Complications: Pleuro-Pancreatic Fistula, Chylous Ascites, and Renal Vein Thrombosis, in a Case of Acute Severe Pancreatitis
Authors: Huda Tanweerul , Mohan Anjaly , Parwez Mohammad Masoom , Pandya Bharati
Published: November 2019

Background Acute pancreatitis is fraught with a variety of complications, which account for the mortality associated. Our case had a fulminant course, with three rare, near-fatal complications and was successfully managed conservatively. Pleural effusion due to pleuro-pancreatic fistula is uncommon, seen in only 1% cases, of which right-sided effusions are rarer still. Management modalities include conservative, endoscopic, and surgical options. Chylous ascites is an extremely rare complication of pancreatitis and is managed with high protein, low lipid diet, restricted to medium-chain triglycerides (MCTs). Extra-splanchnic venous thrombosis is uncommon in pancreatitis, and isolated renal vein thrombosis is very rare.

Case Presentation A 34-year-old, chronic alcoholic male, presented to the outpatient department (OPD) in a state of shock and respiratory distress. Chest radiograph showed massive right-sided pleural effusion. The pleural fluid was hemorrhagic with markedly elevated amylase levels, and contrast-enhanced computed tomography (CECT) confirmed the presence of a right-sided pleuro-pancreatic fistula. Left renal vein thrombosis was also noted. The patient improved with chest drain, intravenous (IV) octreotide, and anticoagulants. Subsequently, he developed hemorrhagic pancreatic ascites, which later turned chylous. This was managed with dietary modifications. The patient had a prolonged recovery but was finally discharged after 45 days.

Conclusion It is a challenge managing the various complications of acute severe pancreatitis. We describe this case to emphasize maintaining a high sensitivity for timely diagnosis and appropriate addressal of all the complications for better patient outcomes.
Radiation Exposure from Fluoroscopy during Hip Arthroscopy
Authors: Seijas Roberto , Català Jordi , Cepas Miguel Ángel , Sallent Andrea , Ares Oscar , Barastegui David
Published: November 2019

Objective Hip arthroscopy for femoroacetabular impingement treatment is a procedure that is not exempted from complications. The most common complications are related to the arthroscopic portals and the traction system. The use of fluoroscopy helps in hip arthroscopy; however, the radiation exposure is a risk that has not yet been studied.

Materials and Methods A retrospective study with 100 arthroscopies was performed. Surgical indication in all cases was femoroacetabular impingement. Surgical times and radiation exposure during the procedure had been recorded and reviewed for the present study.

Results A mean of 138.20 cGy cm2 radiation exposures was observed per patient and procedure for a mean time of radiation exposure of 0.36 minutes. These values are much lower than the values described as being at risk by the nuclear security commissions.

Conclusions Radiation exposure in a hip arthroscopy due to femoroacetabular impingement is in margins well below the limits at risk for the patient.
Dural Venous Sinus Thrombosis after Vestibular Schwannoma Surgery: The Anticoagulation Dilemma
Authors: Brahimaj Bledi C. , Beer-Furlan Andre , Crawford Fred , Nunna Ravi , Urban Matthew , Wu Gary , Abello Eric , Chauhan Vikrant , Kocak Mehmet , Muñoz Lorenzo , Wiet Richard M. , Byrne Richard W.
Published: November 2019

Introduction Dural venous sinus thrombosis (DVST) is a relatively understudied complication of vestibular schwannoma (VS) surgery. Several studies have examined this topic; however, there is limited data on the incidence, clinical progression, and proper management of this patient population.

Methods A retrospective review was performed for patients undergoing surgery for VS at a single institution. All postoperative imaging was reviewed for incidence of DVST. Demographic data were collected including tumor and surgical characteristics along with postoperative course.

Results A total of 63 patients underwent resection of their VS. The incidence of DVST was 34.9%. The operative time was greater in the dural venous sinus thrombosis (DSVT) group, at an average of 6.69 hours versus 4.87 in the no DSVT cohort (p = 0.04). Tumor size was correlationally significant (p = 0.051) at 2.75 versus 2.12 cm greatest diameter. The translabyrinthine approach was most prevalent (68.2%). The side of the thrombosis was ipsilateral to the tumor and surgery in all patients. The sigmoid sinus was most commonly involved (95.5%). Of them, 85% patients had a codominant or thrombus contralateral to the dominant sinus. All patients were asymptomatic. No patients were treated with anticoagulation. Resolution of thrombus was seen in five (22.7%) of the patients on last follow-up imaging. There were no hemorrhagic complications.

Conclusion The overall incidence of DVST was (34.9%) of 63 patients who underwent VS surgery. All patients were asymptomatic and none were treated with anticoagulation. In our study, continuing to observe asymptomatic patients did not lead to any adverse events.
The Role of Interventional Radiology in the Pretransplant Management of Hepatocellular Carcinoma and Portal Vein Thrombosis
Authors: Shmelev Karen , Thornburg Bartley
Published: November 2019

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and is currently the leading indication for liver transplantation in the United States. Liver transplantation may provide a curative option for patients with HCC, but some present outside of the transplant criteria. Additionally, as the criteria for liver transplant eligibility in HCC are expanded and the incidence of disease increases, waitlist times are becoming progressively longer, which increases the chance of a patient suffering from disease progression while awaiting an organ becoming ineligible for transplant. Multiple studies have demonstrated the successful use of locoregional therapies, including trans-arterial chemoembolization and trans-arterial radioembolization, in downstaging HCC to within transplant criteria, as well as in preventing progression of disease in patients already listed for transplant. Cirrhotic patients also commonly develop portal vein thrombosis (PVT), which is a contraindication to transplantation at many centers. PVT can lead to worsened outcomes after transplant depending on the type of portal venous reconstruction that is performed. The purpose of this article is to discuss the integral role of interventional radiology in the care of these patients, including the role of transarterial therapies in the pretransplant treatment of HCC and the use of endovascular techniques to recanalize thrombosed portal veins in order to establish or maintain transplant eligibility.
4.6 GHz lower hybrid wave power control system for EAST
Authors: Ma Wendong , Wang Mao , Wu Zege , Hu Huaichuan , Li Miaohui , Ding Bojiang , Shan Jiafang , Liu Fukun
Published: November 2019

In order to achieve steady state operation in experimental advanced superconducting tokamak (EAST), a 6 MW/4.6 GHz lower hybrid current drive system with twenty-four 250 kW/4.6 GHz high power klystron amplifiers (model VKC7849A) has been developed. A 4.6 GHz lower hybrid wave (LHW) power control system (4.6 GHz LPCS) with continuous wave mode has been set up, which was used to control the LHW power as needed. This paper introduces the architecture and software design of LPCS system, including microwave preamplifier subsystem, power measurement subsystem, power control computers, and so on. Proportional integral differential (PID) closed-loop control time is less than 100 μs due to the use of high-speed acquisition cards and user-programmable Field Programmable Gate Arrays. So far, high power CW operation and power control experiments with PID feedback mode by plasma parameters (beta, loop voltage, and so on) were performed in detail. Results show that 4.6 GHz LPCS is stable and reliable, suggesting that it meets the needs of EAST.
Laser ultrasonic measurements to estimate the elastic properties of rock samples under in situ conditions
Authors: Simpson Jonathan , van Wijk Kasper , Adam Ludmila , Smith Caitlin
Published: November 2019

We present a new noncontact methodology to excite and detect ultrasonic waves in rocks under in situ pressure and temperature conditions. Optical windows in the side of a pressure vessel allow the passage of a laser source and a receiver for noncontact laser ultrasonic measurements. A heating mantle controls the temperature, and a rotational stage inside the vessel makes it possible to obtain measurements as a function of angle. This methodology is the first to combine the advantages of laser ultrasonics (LUS) over traditional transducer methods with measurements under in situ pressure and temperature conditions. These advantages include the absence of mechanical coupling, small sampling area, and broadband recordings of absolute displacement. After describing the experimental setup, we present control experiments to validate the accuracy of this new system for acquiring rock physics data. Densely sampled rotational scans performed on an Alpine Fault ultramylonite rock reveal a decrease in P-wave anisotropy from 62% at atmospheric pressure to 36% at 16 MPa. This result highlights the importance of performing rock physics measurements under in situ confining stress and demonstrates the advantages of the methodology for investigating anisotropy. In addition, a 5.6% decrease in the P-wave velocity of the ultramylonite sample between 20 °C and 100 °C at a constant 10 MPa confining stress demonstrates the capability of this new methodology for acquiring data under both in situ pressure and temperature conditions. This new methodology opens the door for probing the pressure and temperature dependence of the elastic properties of rocks and other materials using LUS techniques.
The τ-function of the Ablowitz-Segur family of solutions to Painlevé II as a Widom constant
Authors: Desiraju Harini
Published: November 2019

The τ-functions of certain Painlevé equations (PVI, PV, and PIII) can be expressed as Fredholm determinants. Furthermore, the minor expansion of these determinants provides an interesting connection to random partitions. This paper is a step toward understanding whether the τ-function of Painlevé II has a Fredholm determinant representation. The Ablowitz-Segur family of solutions are special one parameter solutions of Painlevé II, and the corresponding τ-function is known to be the Fredholm determinant of the Airy kernel. We develop a formalism for open contour in parallel to the one formulated in terms of a suitable combination of Toeplitz operators called the Widom constant and verify that the Widom constant for the Ablowitz-Segur family of solutions is indeed the determinant of the Airy kernel. Finally, we construct a suitable basis and obtain the minor expansion of the Ablowitz-Segur τ-function.
A recurrence network-based convolutional neural network for fatigue driving detection from EEG
Authors: Gao Zhong-Ke , Li Yan-Li , Yang Yu-Xuan , Ma Chao
Published: November 2019

Driver fatigue is an important cause of traffic accidents, which has triggered great concern for detecting drivers’ fatigue. Numerous methods have been proposed to fulﬁll this challenging task, including feature methods and machine learning methods. Recently, with the development of deep learning techniques, many studies achieved better results than traditional feature methods, and the combination of traditional methods and deep learning techniques gradually received attention. In this paper, we propose a recurrence network-based convolutional neural network (RN-CNN) method to detect fatigue driving. To be specific, we first conduct a simulated driving experiment to collect electroencephalogram (EEG) signals of subjects under alert state and fatigue state. Then, we construct the multiplex recurrence network (RN) from EEG signals to fuse information from the original time series. Finally, CNN is employed to extract and learn the features of a multiplex RN for realizing a classification task. The results indicate that the proposed RN-CNN method can achieve an average accuracy of 92.95%. To verify the effectiveness of our method, some existing competitive methods are compared with ours. The results show that our method outperforms the existing methods, which demonstrate the effect of the RN-CNN method.
Angle-dependent strong-field ionization of halomethanes
Authors: Sándor Péter , Sissay Adonay , Mauger François , Gordon Mark W. , Gorman T. T. , Scarborough T. D. , Gaarde Mette B. , Lopata Kenneth , Schafer K. J. , Jones R. R.
Published: November 2019

We study, experimentally and theoretically, the ionization probability of singly halogenated methane molecules, CH3Cl and CH3Br, in intense linearly polarized 800 nm laser pulses as a function of the angle between the molecular axis and the laser polarization. Experimentally, the molecules are exposed to two laser pulses with a relative time delay. The first, weaker pulse induces a nuclear rotational wave packet within the molecules, which are then ionized by the second, stronger pulse. The angle-dependent ionization yields are extracted from fits of the measured delay-dependent ionization signal to a superposition of moments of the rotational wave packet’s angular distribution. Angle-dependent strong-field ionization (SFI) yields are also calculated using time-dependent density functional theory. Good agreement between measurements and theory is obtained. Interestingly, we find a marked difference between the angle-dependence of the ionization yields for these two halomethane species despite the similar structure of their highest occupied molecular orbitals. Calculations reveal that these differences are a result of multichannel (CH3Cl) vs single-channel (CH3Br) ionization and of increased hole localization on Br vs Cl. By adding calculations for CH3F, we can discern clear trends in the ionization dynamics with increasing halogen mass. These results are illustrative, as chemical functionalization and molecular alignment are likely to be important parameters for initiating and controlling charge migration dynamics via SFI.
Linear response for macroscopic observables in high-dimensional systems
Authors: Wormell Caroline L. , Gottwald Georg A.
Published: November 2019

The long-term average response of observables of chaotic systems to dynamical perturbations can often be predicted using linear response theory, but not all chaotic systems possess a linear response. Macroscopic observables of complex dissipative chaotic systems, however, are widely assumed to have a linear response even if the microscopic variables do not, but the mechanism for this is not well-understood. We present a comprehensive picture for the linear response of macroscopic observables in high-dimensional coupled deterministic dynamical systems, where the coupling is via a mean field and the microscopic subsystems may or may not obey linear response theory. We derive stochastic reductions of the dynamics of these observables from statistics of the microscopic system and provide conditions for linear response theory to hold in finite dimensional systems and in the thermodynamic limit. In particular, we show that for large systems of finite size, the linear response is induced via self-generated noise. We present examples in the thermodynamic limit where the macroscopic observable satisfies linear response theory (LRT), although the microscopic subsystems individually violate LRT, as well as a converse example where the macroscopic observable does not satisfy LRT despite all microscopic subsystems satisfying LRT when uncoupled. This latter, maybe surprising, example is associated with emergent nontrivial dynamics of the macroscopic observable. We provide numerical evidence for our results on linear response as well as some analytical intuition.
From ab initio data to high-dimensional potential energy surfaces: A critical overview and assessment of the development of permutationally invariant polynomial potential energy surfaces for single molecules
Authors: Brown Sandra E.
Published: November 2019

The representation of high-dimensional potential energy surfaces by way of the many-body expansion and permutationally invariant polynomials has become a well-established tool for improving the resolution and extending the scope of molecular simulations. The high level of accuracy that can be attained by these potential energy functions (PEFs) is due in large part to their specificity: for each term in the many-body expansion, a species-specific training set must be generated at the desired level of theory and a number of fits attempted in order to obtain a robust and reliable PEF. In this work, we attempt to characterize the numerical aspects of the fitting problem, addressing questions which are of simultaneous practical and fundamental importance. These include concrete illustrations of the nonconvexity of the problem, the ill-conditionedness of the linear system to be solved and possible need for regularization, the sensitivity of the solutions to the characteristics of the training set, and limitations of the approach with respect to accuracy and the types of molecules that can be treated. In addition, we introduce a general approach to the generation of training set configurations based on the familiar harmonic approximation and evaluate the possible benefits to the use of quasirandom sequences for sampling configuration space in this context. Using sulfate as a case study, the findings are largely generalizable and expected to ultimately facilitate the efficient development of PIP-based many-body PEFs for general systems via automation.
Effect of dimensionality on the optical absorption properties of CsPbI3 perovskite nanocrystals
Authors: Liu Albert , Bonato Luiz G. , Sessa Francesco , Almeida Diogo B. , Isele Erik , Nagamine Gabriel , Zagonel Luiz F. , Nogueira Ana F. , Padilha Lazaro A. , Cundiff Steven T.
Published: November 2019

The bandgaps of CsPbI3 perovskite nanocrystals are measured by absorption spectroscopy at cryogenic temperatures. Anomalous bandgap shifts are observed in CsPbI3 nanocubes and nanoplatelets, which are modeled accurately by bandgap renormalization due to lattice vibrational modes. We find that decreasing dimensionality of the CsPbI3 lattice in nanoplatelets greatly reduces electron-phonon coupling, and dominant out-of-plane quantum confinement results in a homogeneously broadened absorption line shape down to cryogenic temperatures. An absorption tail forms at low-temperatures in CsPbI3 nanocubes, which we attribute to shallow defect states positioned near the valence band edge.
Preparation and characterization of DNA array slides via surface Michael addition
Authors: Cheng Fang , Ma Xiaochun , Feng Qiancheng , Wang Hanqi , Yin Meng , He Wei
Published: November 2019

The reliability and stability of array slides are a big concern for array vendors and end users. Herein, we report on a new type of array slide with high reactivity toward DNA probes and low side reaction. A one-step surface reaction via the Michael addition involved in preparing array slides was developed and characterized by x-ray photoelectron spectroscopy, contact angle, and fluorescence labeling. The effects of array fabrication and storage conditions, i.e., spotting solution pH, high humidity, and long-term storage on the reactivity of the slides were examined. The fabricated DNA arrays could realize good hybridization efficiency (38.2% for slides with 0.88 pmol/cm2), low limit of detection (4 × 10−14M), as well as high mismatch selectivity.
The suction effect during freak wave slamming on a fixed platform deck: Smoothed particle hydrodynamics simulation and experimental study
Authors: Sun Peng-Nan , Luo Min , Le Touzé David , Zhang A-Man
Published: November 2019

During the process of wave slamming on a structure with sharp corners, the wave receding after wave impingement can induce strong negative pressure (relative to the atmospheric pressure) at the bottom of the structure, which is called the suction effect. From the practical point of view, the suction force induced by the negative pressure, coinciding with the gravity force, pulls the structure down and hence increases the risk of structural damage. In this work, the smoothed particle hydrodynamics (SPH) method, more specifically the δ+SPH model, is adopted to simulate the freak wave slamming on a fixed platform with the consideration of the suction effect, i.e., negative pressure, which is a challenging issue because it can cause the so-called tensile instability in SPH simulations. The key to overcome the numerical issue is to use a numerical technique named tensile instability control (TIC). Comparative studies using SPH models with and without TIC will show the importance of this technique in capturing the negative pressure. It is also found that using a two-phase simulation that takes the air phase into account is essential for an SPH model to accurately predict the impact pressure during the initial slamming stage. The freak wave impacts with different water depths are studied. All the multiphase SPH results are validated by our experimental data. The wave kinematics/dynamics and wave impact features in the wave-structure interacting process are discussed, and the mechanism of the suction effect characterized by the negative pressure is carefully analyzed.
Phonon traps reduce the quasiparticle density in superconducting circuits
Authors: Henriques Fabio , Valenti Francesco , Charpentier Thibault , Lagoin Marc , Gouriou Clement , Martínez Maria , Cardani Laura , Vignati Marco , Grünhaupt Lukas , Gusenkova Daria , Ferrero Julian , Skacel Sebastian T. , Wernsdorfer Wolfgang , Ustinov Alexey V. , Catelani Gianluigi , Sander Oliver , Pop Ioan M.
Published: November 2019

Out of equilibrium quasiparticles (QPs) are one of the main sources of decoherence in superconducting quantum circuits and one that is particularly detrimental in devices with high kinetic inductance, such as high impedance resonators, qubits, and detectors. Despite significant progress in the understanding of QP dynamics, pinpointing their origin and decreasing their density remain outstanding tasks. The cyclic process of recombination and generation of QPs implies the exchange of phonons between the superconducting thin film and the underlying substrate. Reducing the number of substrate phonons with frequencies exceeding the spectral gap of the superconductor should result in a reduction of QPs. Indeed, we demonstrate that surrounding high impedance resonators made of granular aluminum (grAl) with lower gapped thin film aluminum islands increases the internal quality factors of the resonators in the single photon regime, suppresses the noise, and reduces the rate of observed QP bursts. The aluminum islands are positioned far enough from the resonators to be electromagnetically decoupled, thus not changing the resonator frequency nor the loading. We therefore attribute the improvements observed in grAl resonators to phonon trapping at frequencies close to the spectral gap of aluminum, well below the grAl gap.
Effect of electrode configuration on the sensitivity of nucleic acid detection in a non-planar, flow-through, porous interdigitated electrode
Authors: Cheng Yu-Hsuan , Moura Pedro Antonio Reis , Zhenglong Li , Feng Lixin , Arokiam Siril , Yang Juliana , Hariharan Mahima , Basuray Sagnik
Published: November 2019

Electrical impedance spectroscopy (EIS) sensors, though rapid and cost-effective, often suffer from poor sensitivity. EIS sensors modified with carbon-based transducers show a higher conductance, thereby increasing the sensitivity of the sensor toward biomolecules such as DNA. However, the EIS spectra are compromised by the parasitic capacitance of the electric double layer (EDL). Here, a new shear-enhanced, flow-through nonporous, nonplanar interdigitated microelectrode sensor has been fabricated that shifts the EDL capacitor to high frequencies. Enhanced convective transport in this sensor disrupts the diffusion dynamics of the EDL, shifting its EIS spectra to high frequency. Concomitantly, the DNA detection signal shifts to high frequency, making the sensor very sensitive and rapid with a high signal to noise ratio. The device consists of a microfluidic channel sandwiched between two sets of top and bottom interdigitated microelectrodes. One of the sets of microelectrodes is packed with carbon-based transducer material such as carboxylated single-walled carbon nanotube (SWCNT). Multiple parametric studies of three different electrode configurations of the sensor along with different carbon-based transducer materials are undertaken to understand the fundamental physics and electrochemistry. Sensors packed with SWCNT show femtomolar detection sensitivity from all the different electrode configurations for a short target-DNA. A 20-fold jump in the signal is noticed from the unique working electrode configuration in contrast to the other electrode configurations. This demonstrates the potential of the sensor to have a significant increase in detection sensitivity for DNA and other biomolecules.
Limitations of zT as a figure of merit for nanostructured thermoelectric materials
Authors: Wang Xufeng , Lundstrom Mark
Published: November 2019

Thermoelectric properties of nanocomposites are numerically studied as a function of average grain size or nanoparticle density by simulating the measurements as they would be done experimentally. In accordance with previous theoretical and experimental results, we find that the Seebeck coefficient, power factor, and figure of merit, zT, can be increased by nanostructuring when energy barriers exist around the grain boundaries or embedded nanoparticles. When we simulate the performance of a thermoelectric cooler with the same material, however, we find that the maximum temperature difference, ΔTmax, is much less than expected from the given zT. This occurs because the measurements are done in a way that minimizes Joule heating, but the Joule heating that occurs in operating devices has a large effect for these kinds of materials. The same nanocomposite but without energy barriers at the grain boundaries has a lower measured zT but a higher ΔTmax. The physical reason for these results is explained. The results illustrate the limitations of zT as a figure of merit for nanocomposites with electrically active grain boundaries.
Research and development progress of radio frequency ion source for neutral beam injector at ASIPP
Authors: Xie Yahong , Hu Chundong , Wei Jianglong , Xu Yongjian , Jiang Caichao , Gu Yuming , Zhao Yuanzhe , Cui Qinglong , Liang Lizhen , Chen Shiyong , Wang Qi
Published: November 2019

Neutral beam injection (NBI) is one of the most effective tools of four auxiliary plasma heating methods for fusion plasma heating and current drive. Now, a next generation fusion device, China Fusion Engineering Test Reactor, is under design, and a large negative NBI is foreseen. In order to demonstrate the key technology and performance of a negative ion source, a negative radio frequency (RF) ion source test facility has been developed since 2017 in the Institute of Plasma Physics, Chinese Academy of Science. A prototype RF ion source with double drivers (having the same structure with an inner diameter of 200 mm) was developed and tested on the test facility to preresearch the key technology of the RF plasma generator. The driver is equipped with a water-cooled Faraday shield to protect the alumina cylinder from the plasma, and the plasma expands into the rectangular expansion chamber. The RF power of 100 kW with a frequency of 1 MHz is transferred to the RF driver by a matching unit. The characteristics of plasma discharge were studied with classical diagnostic tools, such as the Langmuir probe and water flow calorimeter. Based on the plasma performance tests, a high power of 82 kW plasma discharge for a long pulse of 1000 s was achieved. In this paper, the details of the ion source design, characteristics of plasma, and future research plan will be presented.
Operation of RF-driven negative hydrogen ion source in China Spallation Neutron Source
Authors: Chen W. , Li H. , Zhu R. L. , Xue K. J. , Cao X. , Lü Y. J. , Liu S. J. , Xiao Y. C. , Liu S. M. , Ouyang H. F.
Published: November 2019

The China Spallation Neutron Source started delivering neutron beams to users in March 2018. To upgrade the beam power to 500 kW and improve the performance of the ion source, an RF-driven negative hydrogen (H−) ion source is under development. The source has a silicon nitride ceramic plasma chamber surrounded by a 4.5-turn antenna. The plasma is ignited by a pulsed DC spark gap and then driven by a 2 MHz solid-state amplifier with a repetition rate of 25 Hz. The commissioning of the source started in January 2019. When uncesiated, it produced about 20 mA beam at an RF power of 32 kW and pulse width of 450 μs. This paper describes the configuration of the ion source, several peculiar technologies used in it, and the first negative hydrogen (H−) ion beam extraction.
Calcium response in bone cells at different osteogenic stages under unidirectional or oscillatory flow
Authors: Wang Shurong , Li Shuna , Hu Man , Huo Bo
Published: November 2019

It was found that preosteoblast MC3T3-E1 cells were less responsive in calcium signaling than mature osteocyte MLO-Y4 cells when a steady fluid flow was exerted on a micropatterned cell network. However, the effect of fluid flow on the calcium response in preosteocyte MLO-A5 was seldom investigated. In the present study, MLO-A5 as well as MC3T3-E1 and MLO-Y4 cells were cultured on a regular substrate with high or low density under unidirectional or oscillatory fluid flow. The results showed that calcium oscillation in the cells during late osteogenesis was significantly stronger than during early osteogenesis regardless of the fluid flow type or the presence of a physical cell–cell connection. Calcium oscillation produced by the oscillatory flow in the three types of cells was stronger than that produced by the unidirectional flow, but MC3T3-E1 and MLO-A5 cells exhibited limited potential for calcium oscillation compared with MLO-Y4 cells. After suramin was used to block the binding of extracellular adenosine triphosphate (ATP) to the membrane P2 receptor, the calcium oscillation in the three types of bone cells with or without physical connections was significantly suppressed as a single responsive peak under unidirectional flow. For the ATP-blocking group of low-density cells under oscillatory flow, the number of oscillation peaks in three types of cells was still more than two. It indicates that besides the ATP pathway, other mechanosensitive calcium pathways may exist under oscillatory flow. The present study provided further evidence for the osteogenic stage-dependent calcium response of bone cells under unidirectional or oscillatory fluid flow.
A new and energy efficient table-top magnetic field generator
Authors: Mandel Savannah
Published: November 2019

Scientists design a low-cost, fully scalable, adjustable, single axis alternating magnetic field generator using permanent magnets.
Development and psychometric testing of a patient-reported inventory to measure patient-centred care in dietetic practice
Authors: Sladdin Ishtar , Chaboyer Wendy , Ball Lauren , Gillespie Brigid M.
Published: November 2019

To develop and psychometrically test a conceptually grounded patient-reported inventory to measure patient-centred care (PCC) in dietetics. Development of the inventory involved conducting a literature search and selecting previously validated scales to reflect the conceptual model of PCC that was developed by the research team. Next, a cross-sectional survey of patients attending individual consultations with Accredited Practicing Dietitians working in primary care was undertaken. To evaluate the factor structure of the inventory, exploratory factor analysis was performed using principal component analysis. Cronbach’s α, inter-item correlations and corrected-item total correlations were computed to test the internal consistency reliability. A total of 133 patients completed the survey. Five factors were extracted, accounting for 78.4% of the variance. All items demonstrated significant loadings (i.e. ≥0.45) and most items had significant loadings on only one factor. High Cronbach’s α values (ranging 0.87–0.97), inter-item correlations (0.46–0.89) and corrected item-total correlations (0.61–0.90) indicated good internal consistency of the inventory, but also potential item redundancy. This study provides the first patient-reported measure of PCC in dietetic practice, which has promising preliminary validity and reliability. With further testing, there is potential for this inventory to be used in future dietetic practice, research and education.