bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical investigation on plasma assisted ignition of methane/air mixture excited by the synergistic nanosecond repetitive pulsed and DC discharge
Authors: Li Shi , Bai Chengjie , Chen Xiaoxiao , Meng Wenjing , Li Li , Pan Jie
Published: September 2020

Plasma assisted combustion provides possibilities for reducing ignition delays and controlling pollutant emissions. The zero-dimensional plasma and combustion models have been built up to numerically investigate the effects of the synergistic nanosecond repetitive pulsed (NRP) and DC discharge on the methane/air plasma assisted ignition. The synergistic discharge means exerting the low voltage DC discharge after the NRP discharge in one period of the discharge plasma. The simulation results indicate that the selective excitation of the vibrationally excited species N2(v), O2(v) and CH4(v) as well as the electronically excited species O2(a1Δg) and O2(b1Σg
+) by the synergistic discharge is superior to that by the NRP discharge when the electron energy has been deposited into different molecular degrees of freedom. The plasma kinetic effect on the ignition enhancement is highly efficient since it can break though the threshold of the thermal effect. Both the kinetic effect and the thermal effect of the NRP discharge on ignition enhancement are relatively weaker than those of the synergistic discharge. Besides, reactions involved the N2 electronically excited species produce abundant O and H, which is conducive to the formation of the methane oxidation intermediates. e + O2 = e + O + O(1D) in the NRP discharge and e + O2 = e + O2(a1Δg) in the synergistic discharge play the crucial roles in the methane/air plasma enhance ignition, respectively.
First-principles equation of state of liquid hydrogen and dissociative transition
Authors: Tian Chunling , Liu Fusheng , Yuan Hongkuan , Chen Hong , Gan Yundan
Published: September 2020

The properties of dense hot hydrogen, in particular the phase transition between the molecular insulating and atomic conductive states, are important in the fields of astrophysics and high-pressure physics. Previous ab initio calculations suggested the metallization in liquid hydrogen, accompanied by dissociation, is a first-order phase transition and ends at a critical point in temperature range between 1500 and 2000 K and pressure close to 100 GPa. Using density functional theoretical molecular dynamics simulations, we report a first-principles equation of state of hydrogen that covers dissociation transition conditions at densities ranging from 0.20 to 1.00 g/cc and temperatures of 600–9000 K. Our results clearly indicate that a drop in pressure and a sharp structural change still occur as the system transforms from a diatomic to monoatomic phase at temperatures above 2000 K, and support the first-order phase transition in liquid hydrogen would end in the temperature about 4500 K.
A weak fault diagnosis scheme for common rail injector based on MGOA-MOMEDA and improved hierarchical dispersion entropy
Authors: Yun Ke , Chong Yao , Enzhe Song , Liping Yang , Quan Dong
Published: September 2020

Aiming at the problem that the common rail injector’s early fault characteristics are very weak and susceptible to random noise and other signal interference, this paper proposes a new common rail injector weak fault diagnosis method based on multipoint optimal minimum entropy deconvolution adjusted based on modified grasshopper optimization algorithm optimization algorithm (MGOA-MOMEDA), improved hierarchical dispersion entropy, and least square support vector machine. First, the fault period T is determined using the multipoint kurtosis spectrum. Through the MGOA optimization algorithm, the optimal filter length L of MOMEDA is obtained adaptively, and the optimal performance filter is used for filter processing. Then, improved hierarchical discrete entropy is used to measure the complexity of the filtered fuel pressure signal to extract weak fault features. Finally, the fault feature vector is input into the LS-SVM multi-classifier to realize the weak fault diagnosis and recognition of the common rail injector. Through experimental verification, the proposed method can effectively achieve the weak fault diagnosis of the common rail injector.
A measurement method for tooth surface errors of straight bevel gears based on 3D model
Authors: Li Tianxing , Li Yulong , Deng Xiaozhong , Li Jinfan
Published: September 2020

Due to the inconsistency between a theoretically designed tooth surface and the actual measured reference surface, the tooth surface error data obtained by the traditional measurement method is unreliable, and incorrectly reflects the machining accuracy of straight bevel gears. This has become a key problem in the current measurement process, and needs to be resolved. In this paper, a new measurement method is proposed to achieve accurate measurement and evaluation of the machining error of straight bevel gears. The 3-dimensional (3D) model surface designed by the manufacturer is directly extracted as a theoretical reference to complete the measurement, which ensures the correctness of the error results. A measurement strategy of normal rotation of the measured point is adopted to make up for the disadvantages of the one-dimensional (1D) probe and improve the measurement accuracy. The problem of the sensitive direction of the probe deviating from the normal direction is compensated for by increasing the dimension of the 1D probe and reducing the dimension of the 3D normal. According to the constructed error calculation model, the minimum tooth surface error is obtained through reconstruction and optimal matching techniques. Finally, the accuracy and effectiveness of the measurement method are verified through measurement comparison experiments. This method solves the technical problem of the inconsistency of the measured reference surface, and uses a low-cost 1D probe to achieve precise measurement of the 3D surface. It not only improves the disadvantages of current measurement methods, but also provides effective technical support for other gear measurements.
Hierarchical cage-frame type nanostructure of CeO2for bio sensing applications: from glucose to protein detection
Authors: Mandal Debabrata , Biswas Sudipta , Chowdhury Ananya , De Debajyoti , Tiwary Chandra Sekar , Gupta Amar Nath , Singh Trilok , Chandra Amreesh
Published: September 2020

Self-assembled hierarchical nanostructures are slowly superseding their conventional counterparts for use in biosensors. These morphologies show high surface area with tunable porosity and packing density. Modulating the interfacial interactions and subsequent particle assembly occurring at the water-and-oil interface in inverse miniemulsions, are amongst the best strategies to stabilize various type of hollow nanostructures. The paper presents a successful protocol to obtain CeO2hollow structures based biosensors that are useful for glucose to protein sensing. The fabricated glucose sensor is able to deliver high sensitivity (0.495μA cm−2nM−1), low detection limit (6.46 nM) and wide linear range (0 nM to 600 nM). CeO2based bioelectrode can also be considered as a suitable candidate for protein sensors. It can detect protein concentrations varying from 0 to 30µM, which is similar or higher than most reports in the literature. The limit of detection (LOD) for protein was ∼0.04µM. Therefore, the hollow CeO2electrodes, with excellent reproducibility, stability and repeatability, open a new area of application for cage-frame type particles.
Cross-field transport in detached helium plasmas in Magnum-PSI
Authors: Tanaka H , Hayashi Y , Kajita S , van der Meiden H J , Yoshikawa M , Vernimmen J W M , Scholten J , Classen I , Morgan T W , Ohno N
Published: September 2020

In this study, enhanced radial transport in a volume-recombining region in detached helium plasmas in a linear device, Magnum-PSI, was investigated. By installing a reciprocating Langmuir probe, electrostatic fluctuations with high spatiotemporal resolutions were measured and analyzed. As a result, the ion-flux profile broadening in the detached state and the coherent plasma structure, which has an internal electric field in the azimuthal direction, were confirmed. By analyzing the emission intensities obtained with a fast framing camera viewing around the probe head, an enhanced fluctuation, which has an azimuthal mode number of m = 1, was found to be correlated with radial plasma ejection. This m = 1 mode rotates by the drift with the radial electric field and magnetic field and is correlated with the m = 0 mode. These two modes behave like a predator and prey; they quasi-periodically appear with about a quarter-period shift. Because the ion flux flowing into the target plate decreases when the radial transport is enhanced, this cross-field transport disperses the ion flux and decreases the maximum heat load applied to the target.
Linearity/intermodulation distortion analysis of tunneling and thermionic emission mechanisms; design proposal and high frequency investigation
Authors: Yadav Shivendra , Khare Anuj , Anju  , Mishra Guru Prasad , Aslam Mohd.
Published: September 2020

The article provides an opportunity to study the linearity/intermodulation distortion, radiofrequency, and internal physical behavior of a device when the thermionic emission and tunneling transport are brought together. Thermionic emission is arranged vertically in the channel by an additional electron source (AES) along with the conventional horizontal tunneling in an electrically doped tunnel field-effect transistor (C-ED-TFET). The combined mechanism (tunneling and thermionic emission) offers a drastic improvement in the linearity parameters of the C-ED-TFET. In addition, the combined mechanism of carrier transport offers not only better linearity but also drastically improved DC and radiofrequency characteristics compared with the individual phenomena. It is obvious that thermionic emission carrier transport leads to higher leakage current compared to pure tunneling; hence, the presence of an AES causes a rise in the leakage current. Therefore, in the final state of the art work-function engineering is applied at the control gate that offers a reduction in the leakage current (1× 10−18 A µm–1) due to the formation of a potential well in the channel region in the OFF state. Moreover, the final proposal also possesses a short drain electrode, which is beneficial for suppressing the negative conductance (inherent issue) of the TFET.
VIPER: an industrially scalable high-current high-temperature superconductor cable
Authors: Hartwig Zachary S , Vieira Rui F , Sorbom Brandon N , Badcock Rodney A , Bajko Marta , Beck William K , Castaldo Bernardo , Craighill Christopher L , Davies Michael , Estrada Jose , Fry Vincent , Golfinopoulos Theodore , Hubbard Amanda E , Irby James H , Kuznetsov Sergey , Lammi Christopher J , Michael Philip C , Mouratidis Theodore , Murray Richard A , Pfeiffer Andrew T , Pierson Samuel Z , Radovinsky Alexi , Rowell Michael D , Salazar Erica E , Segal Michael , Stahle Peter W , Takayasu Makoto , Toland Thomas L , Zhou Lihua
Published: September 2020

High-temperature superconductors (HTS) promise to revolutionize high-power applications like wind generators, DC power cables, particle accelerators, and fusion energy devices. A practical HTS cable must not degrade under severe mechanical, electrical, and thermal conditions; have simple, low-resistance, and manufacturable electrical joints; high thermal stability; and rapid detection of thermal runaway quench events. We have designed and experimentally qualified a vacuum pressure impregnated, insulated, partially transposed, extruded, and roll-formed (VIPER) cable that simultaneously satisfies all of these requirements for the first time. VIPER cable critical currents are stable over thousands of mechanical cycles at extreme electromechanical force levels, multiple cryogenic thermal cycles, and dozens of quench-like transient events. Electrical joints between VIPER cables are simple, robust, and demountable. Two independent, integrated fiber-optic quench detectors outperform standard quench detection approaches. VIPER cable represents a key milestone in next-step energy generation and transmission technologies and in the maturity of HTS as a technology.
Impact of interface-state formation on the charge-carrier dynamics at organic-metal interfaces
Authors: Marks M , Armbrust N , Güdde J , Höfer U
Published: September 2020

We study the role of electronic interface states on the electron transfer dynamics between layers of the organic semiconductor 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) and the (111) and (100) surfaces of silver. For this purpose, we investigate the change of the decay dynamics of the first (n = 1) image-potential state on these surfaces upon adsorption of an ordered monolayer of PTCDA by means of time-resolved two-photon photoemission (2PPE). We find that the already short lifetime of the (n = 1)-state on Ag(111) is only slightly further reduced by PTCDA adsorption, whereas a much stronger reduction by a factor of three is observed for adsorption on Ag(100) resulting in similar lifetimes for both orientations. We show by model calculations on the basis of an analytical one-dimensional pseudo-potential that the enhanced decay for PTCDA/Ag(100) can be attributed to the opening of an additional channel for electron-electron scattering by the formation of an interface state which is derived from the Shockley-type surface resonance of Ag(100).
Simulating extremal temporal correlations
Authors: Spee Cornelia , Budroni Costantino , Gühne Otfried
Published: September 2020

The correlations arising from sequential measurements on a single quantum system form a polytope. This is defined by the arrow-of-time (AoT) constraints, meaning that future choices of measurement settings cannot influence past outcomes. We discuss the resources needed to simulate the extreme points of the AoT polytope, where resources are quantified in terms of the minimal dimension, or ‘internal memory’ of the physical system. First, we analyze the equivalence classes of the extreme points under symmetries. Second, we characterize the minimal dimension necessary to obtain a given extreme point of the AoT polytope, including a lower scaling bound in the asymptotic limit of long sequences. Finally, we present a general method to derive dimension-sensitive temporal inequalities for longer sequences, based on inequalities for shorter ones, and investigate their robustness to imperfections.
Safety Analysis of Mooring Hawser of FSO and SPM Buoy in Irregular Waves
Authors: Asmara I P S , Sumardiono  , Wibowo V A P
Published: September 2020

This paper provides a method to analyze the safety factor of the hawser line between Floating Storage Offloading (FSO) and Single Point Mooring (SPM) by using motions simulation. The simulation was conducted based on irregular wave arrival for 1 year and 100 years. A case study for a mooring system of a 55,081 tons displacement of FSO tanker to a 360 tons displacement of SPM buoy was simulated with the existing hawser line length of 45 m and the new hawser line length of 70 m. The wave forces and moments are computed using Ansys Aqwa based on the 3D Panel Method both in the frequency domain and time domain. The wave periods are 6 s and 8 s for the 1-year and 100-year data, respectively. The safety factor of the hawser line significantly improves by using the new hawser line.
Experimental Study of Collector Performance Solar Air Heater with Dimple Staggered Arrangement On A V-Corrugated Absorber Plate
Authors: Neno S , Ichsani D
Published: September 2020

The energy crisis is currently the world’s major issue in recent decades. The use of energy is almost in all aspects and all human activity depends on energy. For now, the world’s energy consumption is still in dominance by fossil energy (petroleum, gas, and coal). Given the limited supply of energy sources, the energy alternative that can be utilized is solar energy. Solar energy utilization technology can be distinguished into two namely the conversion of solar energy into electricity through solar cells, and the utilization of solar heat using solar collectors for drying. This study discusses the influence of the Absorber plate of V-Corrugated dimple form with a staggered arrangement against the performance of solar collectors. The diameter of a dimple on the absorber plate measuring 5, 7, 9 mm. Experiments using halogen lamps with radiation intensity varying from 431; 575; 718 W/m2 and varying mass flow rate of 0.001; 0.002; 0.004; 0.006 kg/s. The results obtained are the magnitude of useful energy that is absorbed by the working fluid of solar collectors directly proportional to the increase in mass flow rate and radiation intensity. For the V-Corrugated absorber plate with a diameter of a 9 mm dimple, the highest Qusefull is achieved at a mass flow rate of 0.006 kg/s with a radiation intensity of 718 W/m2 of 65.9 W and the highest efficiency of 65.7 % achieved at a mass flow rate of 0.006 kg/s with radiation intensity of 718 W/m2.
A Study of the effectiveness Fin Stabilizer on Unsada Water Tour Bus to Comfort the Rolling Period to Support Toba Lake Tourism
Authors: Moganti V D , Garetno R E , Irvana R , Fadillah A
Published: September 2020

Lake Toba is one of the five super priority national tourist destinations. To support Lake Toba tourism. a suitable and safe mode of transportation is needed and to be able to provide an attraction for tourists. See this opportunity. we plan to make this mode of transportation. The Air Unsada Tourism Bus is one of the modes of transportation that is a pioneer of new modes of tourism transportation in Indonesia. especially on Lake Toba. North Sumatra. The Unsada Water Tourism Bus is an amphibious bus that can move both on land and in water. The Unsada Air Tour Bus is specially designed using fin stabilizers on the bus body. like the hull of a ship in general. The purpose of this research is to design a Water Tourism Bus that can provide comfort and safety for tourists. in this case that is how to minimize the rolling time on the Air Unsada Tourism Bus to pay attention to the condition of Lake Toba’s waters which is quite extreme. In designing this bus using the dimensions of a conventional bus with a length of 13.115 meters. 2.5 meters wide. As high as 3.8 meters. and a double decker used for the roof so that tourists can enjoy views of Lake Toba. The method used for the calculation is IMO stability level 2 and also uses Indonesian land transportation regulations contained in government regulation no 55 chapter 3 part 3d 2012. For calculations and analysis using the Maxsurf software. Meet the IMO standard parametric rolling level 2. The results obtained are 0,000239 below the 0.06 standard.
Application of BLOCPLAN algorithm as liquified natural gas (LNG) regasification terminal design method
Authors: Ulfauzi Z , Artana K B , Handani D W
Published: September 2020

In the layout design of buildings using applications, such as in the fields of civil engineering, shipping, architecture, there are many design algorithm systems that have been developed. Design algorithm is an approaching method in design where the computer system has been processed with several formulas to produce designs automatically and efficiently. In this paper the researcher try to use one of the design algorithm to designing the LNG terminal layout, called BLOCPLAN algorithm. The BLOCPLAN algorithm is used to improve the efficiency of space utilization and facility placement. BLOCPLAN works by generating several terminal layouts with a direct appraisal system. A most efficient design will be selected from generated designs after re-analysis process. By using the BLOCPLAN algorithm the pipe length used in terminal will be less so it will be more cost-effective. In determining the main terminal facilities, Excel Solver is also used to choose the best scenario with low investment capital. Design algorithm system can effectively support the recommendation process of a more comprehensive layout design. This research is expected to facilitate the designers work because by using this method the designer no longer need to carry out complex processes from the initial stage of design.
A Gas Infrastructure Pathways in East Java Using System Dynamic Approach
Authors: Haekal M , Artana K B , Handani D W
Published: September 2020

As a developing country, Indonesia has been consuming energy with 114 Million Ton Oil Equivalent (MTOE) and estimated that the demand for energy will increase up to 167,4 MTOE in 2050 by Indonesian Energy Ministry. It is also estimated that natural gas will play the role in fulfilling the energy demand in Indonesia. However, in utilizing the natural gas spread of the regions, Indonesia still lack of natural gas infrastructures. As natural gas infrastructures are playing a vital role on those problems, the condition of supply demand, capacity of infrastructure and the effectiveness of the route need to be adjusted and considered. In this study, system dynamic method is employed in order to forecast the supply and demand of natural gas in East Java Province. In addition, a simulation is carried out to optimize and simulate the scenario model of the natural gas infrastructure at certain time-year period. With the constraint and condition given to the system dynamics, a supply-demand condition in East Java area that mainly comes from electrical power generation, industry and household is assessed. Based on developed scenarios, the model is expected to fulfil the needs of natural gas in East Java. The possibility of establishing new LNG terminal in certain location or expanding the capacity of existing facilities are also considered in this study.
Analysis of Automation Implementation in Indonesia Container Terminal
Authors: Pamungkas B , Saut Gurning R O
Published: September 2020

Indonesia container terminals have several prospect factors in implementing automation. Consider that condition, this paper provides automation parameters the are used to measure the container terminal readiness to implement automation. Those parameters also sorted out using Best-Worst Method and assisted by the experts in weighting the parameters. The four parameters in sequence order are container throughput, yard capacity, investment cost, and environment management. Besides, Indonesia container terminals must handle several constraint factors in implementing automation such as automation requires high investment, low return investment, labor conflict, incapability of Indonesia electric provider, and Human resource in Indonesia still abundant.
The Effect of Bulbous Bow on the Probability of Slamming on Hull (Case Study on Container vessel 4200 DWT)
Authors: Mustain M , Siswanti H , Islam M
Published: September 2020

One of the environmental factors that influence the probability of a ship accident is the wave height. Extreme wave height can cause the bow of the ship crashing on the surface of the sea water (slamming). Slamming can cause local buckling and deformation on the ship’s bottom plate at the bow. At certain conditions the slamming can cause damage to the ship’s bow structure. This research discussed the effect of using bulbous bow on slamming probability on 4200 DWT container vessel. The analysis was carried out at 1.5 - 3 meter wave height conditions, according to the wave height conditions on this ship’s shipping route in Makassar Strait. The geometrical dimension is LPR = 2.116 m, BB = 2.805 m and ZB = 2,42 m. The analysis of the motion response of the ship is carried out on two types of motion heaving and pitching. In maximum draft conditions, 5.5 meters and speed 11.9 knots (6.12 m/s) and a heading angle of 180°. The next step is calculation of response spectrum by multiplying the wave spectrum with RAO. From the analysis, known that higher wave produced greater response of heaving and pitching motion. And also higher wave produced higher relative bow motion spectrum. The probability of slamming of 4200 DWT ships with bulbous bow is smaller than without bulbous bow. At a certain wave height (2-3 meters) indicates that the bulbous bow reduces the slamming probability approximately 17-49%. The intensity slamming per hour of 4200 DWT ships with bulbous bow is smaller than without bulbous bow. It is indicates that the bulbous bow reduces the slamming intensity per hour approximately 24-45%.
A Proposal for Criteria of Safe and Functional Port: The Perspective of Seafarers
Authors: Sulistiyono A B , Mutmainnah W , Seputro F H , Furusho M
Published: September 2020

Indonesia is the largest archipelagic state in the world with abundant natural resources and its geographical location. However, domestic connectivity is one of the major national issues that cause economic disparity among regions in Indonesia. The government is giving attention to maritime infrastructure development, especially port construction. Port construction process, applying other infrastructure construction standard in Indonesia, is started by setting an aim to get profit from the owner company. Then the owner company choose designer consultant to make a Detailed Engineering Design. After that, the tender process is conducted to select Construction Company. Finally, the chosen contractor start the construction. Seafarers, as the intense user of port facilities, have to accept the port condition as it is. Opinions from seafarers regarding the safety and functionality of ports would make the port acceptable for seafarer and could improve working performance at ports and support better-living conditions in the surrounding areas. Thus, the objectives of the paper are to find the criteria of the safe and functional port, to find the safest and most functional port standards from seafarers` point of view, and to propose the recommendation program to improve the level of safety and functionality of the port, especially in Tanjung Perak Port as case study. The discussion will be focused on passenger terminal and RoRo ship, so the seafarers who are onboard the Roro ships are targeted as respondent. Safety of port and functionality of port are defined using 4M Overturned Pyramid (MOP) model. Seven points of criteria of the safe and functional seaport have been obtained. The questionnaire is then created to approach the seafarers’ opinion regarding the safety and functionality of the port. The port that durable in all-weather condition (strong wind, wave height, tide, temperature) is chosen as the safest and most functional port by seafarers.
The Impact of Implementation New Regulation on Maritime Industry: A Review of Implementation BWTS
Authors: Hardiyanto  , Pitana T , Handani D W
Published: September 2020

IMO as an international institution has issued various regulations about the safety and environment. Based on regulations regarding BWT (Ballast Water Management) issued by IMO on international conventions to control ballast water was held in 2004. Indonesian Presidential Regulation number 132 of 2015 states that it has participated in ratifying the Convention. The impact of implementing regulations passed on the existence of several maritime industry sectors must be assessed and considered. The installation of instruments on ships causes incur greater costs to be spent by shipowners which have an impact on the survival of the industry. This study analyzes the impact of applying this regulation by conducted a literature study to examine the maritime industry that will be affected and potential costs that will be required after implementation of this regulation. The result of this study has found analyze of impact implementation of new regulation should be determined. The method to determine this impact can be done using simulation such as a developed dynamic system.
Maritime Safety Education with Augmented Reality (AR) Technology (Case study: Introduction of Ship Safety Plan)
Authors: Pitana T , Prastowo H , Purnama P M R
Published: September 2020

Augmented Reality is a technology that can combine 2-dimension or 3-dimension virtual objects to be added to the real environment and combine them so that they can create mixed realities and project them into real-time. Augmented Reality is a field in which virtual objects are integrated into a real environment in real-time. This technology-based on the android application is applied to facilitate education media and inspection for life-saving appliances on board. All life-saving appliances can be displayed alongside the information and the location of the object. Utilizing AR is possible to be used as educational media to get precise information relating to the locations, objects, and quantity. Therefore, by becoming visible, it is possible to increase the sense of realism and immersion of this technology.
Resonant amplification of surface plasmon polaritons with an electric current in a single-walled carbon nanotube lying on a spatially modulated substrate
Authors: Kadochkin Alexey S , Moiseev Sergey G , Dadoenkova Yuliya S , Bentivegna Florian F L , Svetukhin Vyacheslav V , Zolotovskii Igor O
Published: September 2020

We discuss the possibility of using a direct electric current pump in order to amplify a mid-infrared surface plasmon polariton (SPP) in a single-walled carbon nanotube (CNT) deposited on a substrate. Amplification is achieved providing that the phase velocity of the SPP and the drift velocity of the charge carriers in the nanotube are matched. Calculating the amplification characteristics involves numerical simulations that allow to account for the influence of the substrate on the dispersion and inhomogeneity of the plasmon mode field distribution across the CNT. The spectral behaviour of an amplified SPP is shown to exhibit a high sensitivity to variations of the refractive index of the substrate supporting the CNT. We propose a design for the resonant amplification of SPPs with a DC current pump, in which a distributed resonator is obtained with a periodical modulation of the refractive index of the substrate.
Carbon-11 and Carbon-12 beam range verifications through prompt gamma and annihilation gamma measurements: Monte Carlo simulations
Authors: Chalise Ananta Raj , Chi Yujie , Lai Youfang , Shao Yiping , Jin Mingwu
Published: September 2020

Range uncertainty remains a big concern in particle therapy, as it may cause target dose degradation and normal tissue overdosing. Positron emission tomography (PET) and prompt gamma imaging (PGI) are two promising modalities for range verification. However, the relatively long acquisition time of PET and the relatively low yield of PGI pose challenges for real-time range verification. In this paper, we explore using the primary Carbon-11 (C-11) ion beams to enhance the gamma yield compared to the primary C-12 ion beams to improve PET and PGI by using Monte Carlo simulations of water and PMMA phantoms at four incident energies (95, 200, 300, and 430 MeV u−1). Prompt gammas (PGs) and annihilation gammas (AGs) were recorded for post-processing to mimic PGI and PET imaging, respectively. We used both time-of-flight (TOF) and energy selections for PGI, which boosted the ratio of PGs to background neutrons to 2.44, up from 0.87 without the selections. At the lowest incident energy (100 MeVu-1), PG yield from C-11 was 0.82 times of that from C-12, while AG yield from C-11 was 6 ∼ 11 folds higher than from C-12 in PMMA. At higher energies, PG differences between C-11 and C-12 were much smaller, while AG yield from C-11 was 30%∼90% higher than from C-12 using minute-acquisition. With minute-acquisition, the AG depth distribution of C-11 showed a sharp peak coincident with the Bragg peak due to the decay of the primary C-11 ions, but that of C-12 had no such one. The high AG yield and distinct peaks could lead to more precise range verification of C-11 than C-12. These results demonstrate that using C-11 ion beams for potentially combined PGI and PET has great potential to improve online single-spot range verification accuracy and precision.
Percolation with plasticity for neuromorphic systems
Authors: Karpov V G , Serpen G , Patmiou Maria
Published: September 2020

We develop a theory of percolation with plasticity media (PWPs) rendering properties of interest for neuromorphic computing. Unlike the standard percolation, they have multiple (N ≫ 1) interfaces and exponentially large number (N!) of conductive pathways between them. These pathways consist of non-ohmic random resistors that can undergo bias induced nonvolatile modifications (plasticity). The neuromorphic properties of PWPs include: multi-valued memory, high dimensionality and nonlinearity capable of transforming input data into spatiotemporal patterns, tunably fading memory ensuring outputs that depend more on recent inputs, and no need for massive interconnects. A few conceptual examples of functionality here are random number generation, matrix-vector multiplication, and associative memory. Understanding PWP topology, statistics, and operations opens a field of its own calling upon further theoretical and experimental insights.
Neurodegenerative disease is associated with increased incidence of epilepsy: a population based study of older adults
Authors: Blank Leah J , Acton Emily K , Thibault Dylan , Willis Allison W
Published: September 2020

Objective

To determine the incidence of epilepsy among Medicare beneficiaries with a new diagnosis of Alzheimer dementia (AD) or Parkinson disease (PD).

Methods

Retrospective cohort study of Medicare beneficiaries with an incident diagnosis of AD or PD in the year 2009. The 5-year incidence of epilepsy was examined by sociodemographic characteristics, comorbidities and neurodegenerative disease status. Cox regression models examined the association of neurodegenerative disease with incident epilepsy, adjusting for demographic characteristics and medical comorbidities.

Results

We identified 178,593 individuals with incident AD and 104,157 individuals with incident PD among 34,054,293 Medicare beneficiaries with complete data in 2009. Epilepsy was diagnosed in 4.45% (7,956) of AD patients and 4.81% (5,010) of PD patients between 2009 and 2014, approximately twice as frequently as in the control sample. Minority race/ethnicity was associated with increased risk of incident epilepsy. Among individuals with AD and PD, stroke was associated with increased epilepsy risk. Traumatic brain injury (TBI) was associated with increased epilepsy risk for individuals with PD. Depression was also associated with incident epilepsy (AD adjusted hazard ratio (AHR): 1.23 (1.17–1.29), PD AHR: 1.45 (1.37–1.54)). In PD only, a history of hip fracture (AHR, 1.35 (1.17–1.57)) and diabetes (AHR, 1.11 (1.05–1.18) were also associated with increased risk of epilepsy.

Conclusion

Incident epilepsy is more frequently diagnosed among neurodegenerative disease patients, particularly when preceded by a diagnosis of depression, TBI or stroke. Further studies into the differences in epilepsy risk between these two populations may help elucidate different mechanisms of epileptogenesis.
Asymmetries affecting aggressive contests between solitary parasitoids: the effect of host species
Authors: Guerra-Grenier Eric , Abram Paul K , Brodeur Jacques
Published: September 2020

Conflicts in animals are usually resolved based on asymmetries, where contest winners are often those that value a resource the most and/or those who have the greatest potential to retain it. In parasitoid wasps, contests between females determine which individual exploits hosts for offspring production. Previous studies on solitary parasitoids rarely considered the role of biotic factors generating phenotypic variation that could influence the strength of asymmetries. Some parasitoid species parasitize host species of various sizes, producing offspring that vary considerably in size and potentially fighting ability. In this study, we reared the egg endoparasitoid Telenomus podisi (Hymenoptera: Scelionidae) on two host species to measure the effect of body size on contest resolution and how it interacts with ownership and resource value (RV) asymmetries. Our results showed that ownership status best predicts the final contest outcome when similar-sized wasps fight over hosts. The frequency and outcomes of individual fights structuring contests were better explained by the difference in the number of eggs laid in the hosts by each female at a given time. When contestants varied in body size, larger intruders frequently dislodged small owners regardless of ownership and RV asymmetries. These results imply that body size is an important factor to consider in solitary parasitoid contests and that it can overshadow the effects of other asymmetries. Our study suggests that host community diversity could have a direct effect on parasitoid contests and that biotic communities, through their effects on animal phenotypes, may play an underrated role in contest resolution.
Bayesian design of clinical trials using joint models for longitudinal and time-to-event data
Authors: Xu Jiawei , Psioda Matthew A , Ibrahim Joseph G
Published: September 2020

Joint models for longitudinal and time-to-event data are increasingly used for the analysis of clinical trial data. However, few methods have been proposed for designing clinical trials using these models. In this article, we develop a Bayesian clinical trial design methodology focused on evaluating the treatment’s effect on the time-to-event endpoint using a flexible trajectory joint model. By incorporating the longitudinal outcome trajectory into the hazard model for the time-to-event endpoint, the joint modeling framework allows for non-proportional hazards (e.g., an increasing hazard ratio over time). Inference for the time-to-event endpoint is based on an average of a time-varying hazard ratio which can be decomposed according to the treatment’s direct effect on the time-to-event endpoint and its indirect effect, mediated through the longitudinal outcome. We propose an approach for sample size determination for a trial such that the design has high power and a well-controlled type I error rate with both operating characteristics defined from a Bayesian perspective. We demonstrate the methodology by designing a breast cancer clinical trial with a primary time-to-event endpoint and where predictive longitudinal outcome measures are also collected periodically during follow-up.
Tumour necrosis factor induces increased production of extracellular amyloid-β- and α-synuclein-containing aggregates by human Alzheimer’s disease neurons
Authors: Whiten Daniel R , Brownjohn Philip W , Moore Steven , De Suman , Strano Alessio , Zuo Yukun , Haneklaus Moritz , Klenerman David , Livesey Frederick J
Published: September 2020

In addition to increased aberrant protein aggregation, inflammation has been proposed as a key element in the pathogenesis and progression of Alzheimer’s disease. How inflammation interacts with other disease pathways and how protein aggregation increases during disease are not clear. We used single-molecule imaging approaches and membrane permeabilization assays to determine the effect of chronic exposure to tumour necrosis factor, a master proinflammatory cytokine, on protein aggregation in human-induced pluripotent stem cell-derived neurons harbouring monogenic Alzheimer’s disease mutations. We report that exposure of Alzheimer’s disease neurons, but not control neurons, to tumour necrosis factor induces substantial production of extracellular protein aggregates. Aggregates from Alzheimer’s disease neurons are composed of amyloid-β and α-synuclein and induce significant permeabilization of lipid membranes in an assay of pathogenicity. These findings provide support for a causal relationship between two crucial processes in Alzheimer’s disease pathogenesis and suggest that targeting inflammation, particularly tumour necrosis factor, may have beneficial downstream effects on ameliorating aberrant protein aggregation and accumulation.
PTPN11 Mutations in the Ras-MAPK Signaling Pathway Affect Human White Matter Microstructure
Authors: Fattah Mustafa , Raman Mira M , Reiss Allan L , Green Tamar
Published: September 2020

We examined whether PTPN11 mutations affect the white matter connectivity of the developing human brain. Germline activating mutations to the PTPN11 gene cause overactivation of the Ras-Mitogen-Activated Protein Kinase pathway. Activating mutations cause Noonan syndrome (NS), a developmental disorder associated with hyperactivity and cognitive weakness in attention, executive function, and memory. In mouse models of NS, PTPN11 mutations cause reduced axon myelination and white matter formation, while the effects of PTPN11 mutations on human white matter are largely unknown. For the first time, we assessed 17 children with NS (9 females, mean age, 8.68 ± 2.39) and 17 age- and sex-matched controls (9 female, mean age, 8.71 ± 2.40) using diffusion brain imaging for white matter connectivity and structural magnetic resonance imaging to characterize brain morphology. Children with NS showed widespread reductions in fractional anisotropy (FA; 82 613 voxels, t = 1.49, P < 0.05) and increases in radial diffusivity (RD; 94 044 voxels, t = 1.22, P < 0.05), denoting decreased white matter connectivity. In NS, the FA of the posterior thalamic radiation correlated positively with inhibition performance, whereas connectivity in the genu of the corpus callosum was inversely associated with auditory attention performance. Additionally, we observed negative and positive correlations, respectively, between memory and the cingulum hippocampus, and memory and the cingulum cingulate gyrus. These findings elucidate the neural mechanism underpinning the NS cognitive phenotype, and may serve as a brain-based biomarker.
Duration of Outpatient Antibiotic Therapy for Common Outpatient Infections, 2017
Authors: King Laura M , Hersh Adam L , Hicks Lauri A , Fleming-Dutra Katherine E
Published: September 2020

Our objective was to describe the duration of antibiotic therapy for the management of common outpatient conditions. The median duration of antibiotic courses for most common conditions, except for acute cystitis, was 10 days, in many cases exceeding guideline-recommended durations.
Adherence to quality indicators for ST-elevation myocardial infarction and its relation to mortality: a hospital network analysis from the Belgian STEMI database
Authors: Bosmans Sara , Sluyts Yasmine , Lysens de Oliveira e Silva-Van Acker Jonas , Van Caenegem Olivier , Sinnaeve Peter R , Dubois Philippe , Vranckx Pascal , Gevaert Sofie , Coussement Patrick , Beauloye Christophe , Evrard Patrick , Argacha Jean-François , De Raedt Herbert , Wouters Kristien , Claeys Marc J
Published: September 2020

Aims

To assess the adherence to established quality indicators (QIs) for ST-elevation myocardial infarction (STEMI) at the hospital-network level and its relation to outcome.

Methods and results

The data of 7774 STEMI patients admitted to 32 STEMI networks during the period 2014–18 were extracted from the Belgian STEMI database. Five QIs [primary percutaneous coronary intervention use, diagnosis-to-balloon time (DiaTB) <90 min, door-to-balloon time (DoTB) <60 min, P2Y12 inhibitor and statin prescription at discharge, and a composite QI score ranging from 0 to 10] were correlated with in-hospital mortality adjusted for differences in baseline risk profile (TIMI risk score). The median composite QI score was 6.5 [interquartile range (IQR) 6–8]. The most important gaps in quality adherence were related to time delays: the recommended DiaTB and DoTB times across the different networks were achieved in 68% (IQR 53–71) and 67% (IQR 50–78), respectively. Quality adherence was better in networks taking care of more high-risk STEMI patients. The median in-hospital mortality among the STEMI networks was 6.4% (IQR 4.1–7.9%). There was a significant independent inverse correlation between the composite QI score and in-hospital mortality (partial correlation coefficient: −0.45, P = 0.013). Stepwise regression analysis revealed that among the individual QIs, prolonged DiaTB was the most important independent outcome predictor.

Conclusion

Among established STEMI networks, the time delay between diagnosis and treatment was the most variable and the most relevant prognostic QI, underscoring the importance of assessing quality of care throughout the whole network.
Non-vitamin K oral anticoagulants for secondary stroke prevention in patients with atrial fibrillation
Authors: Diener Hans-Christoph , Hankey Graeme J , Easton J Donald , Lip Gregory Y H , Hart Robert G , Caso Valeria
Published: September 2020

The aims of this article are to review the evidence regarding the use of non-vitamin K oral anticoagulants (NOACs) for secondary stroke prevention as compared to vitamin K antagonists in patients with atrial fibrillation (AF) and in patients with embolic strokes of uncertain source (ESUS), and when to initiate or resume anticoagulation after an ischaemic stroke or intracranial haemorrhage.

Four large trials compared NOACs with warfarin in patients with AF. In our meta-analyses, the rate of all stroke or systemic embolism (SE) was 4.94% with NOACs vs. 5.73% with warfarin. Among the patients with AF and previous transient ischaemic attack or ischaemic stroke, the rate of haemorrhagic stroke was halved with a NOAC vs. warfarin, and the rate of major bleeding was 5.7% with a NOAC vs. 6.4% with warfarin. There was no significant difference in mortality. In a trial comparing apixaban with aspirin in patients with AF, the rate of stroke or SE was 2.4% at 1 year with apixaban vs. 9.2% at 1 year with aspirin and the rates of major bleeding were 4.1% with apixaban vs. 2.9% with aspirin. Data from registries confirmed the results from the randomized trials. Initiation or resumption of anticoagulation after ischaemic stroke or cerebral haemorrhage depends on the size and severity of stroke and the risk of recurrent bleeding. Two large trials tested the hypothesis that NOACs are more effective than 100 mg aspirin in patients with ESUS. Neither trial showed a significant benefit of the NOAC over aspirin.

In the meta-analysis, the rate all stroke or SE was 4.94% with NOACs vs. 5.73% with warfarin and the rate of haemorrhagic stroke was halved with a NOAC. The four NOACs had broadly similar efficacy for the major outcomes in secondary stroke prevention.
Automatic Quantification of Tandem Walking Using a Wearable Device: New Insights Into Dynamic Balance and Mobility in Older Adults
Authors: Ganz Natalie , Gazit Eran , Giladi Nir , Dawe Robert J , Mirelman Anat , Buchman Aron S , Hausdorff Jeffrey M
Published: September 2020

Background

Wearable sensors are increasingly employed to quantify diverse aspects of mobility. We developed novel tandem walking (TW) metrics, validated these measures using data from community-dwelling older adults, and evaluated their association with mobility disability and measures of gait and postural control.

Methods

Six hundred ninety-three community-dwelling older adults (age: 78.69 ± 7.12 years) wore a 3D accelerometer on their lower back while performing 3 tasks: TW, usual-walking, and quiet standing. Six new measures of TW were extracted from the sensor data along with the clinician’s conventional assessment of TW missteps (ie, trip other loss of balance in which recovery occurred to prevent a fall) and duration. Principal component analysis transformed the 6 new TW measures into 2 summary TW composite factors. Logistic regression models evaluated whether these TW factors were independently associated with mobility disability.

Results

Both TW factors were moderately related to the TW conventional measures (r < 0.454, p < .001) and were mildly correlated with usual-walking (r < 0.195, p < .001) and standing, postural control (r < 0.119, p < .001). The TW frequency composite factor (p = .008), but not TW complexity composite factor (p = .246), was independently associated with mobility disability in a model controlling for age, sex, body mass index, race, conventional measures of TW, and other measures of gait and postural control.

Conclusions

Sensor-derived TW metrics expand the characterization of gait and postural control and suggest that they reflect a relatively independent domain of mobility. Further work is needed to determine if these metrics improve risk stratification for other adverse outcomes (eg, falls and incident disability) in older adults.