bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance analysis of congestion control protocols over 5G mmWave links
Authors: Luo Yi , Wang Min , Zhao Deteng , Liu Chun
Published: May 2022

Millimeter wave technology is an important basic technology in 5G applications. It has higher bandwidth and lower delay. But high dynamics of the channel poses a major challenge to the design of congestion control protocols. Based on ns3, this paper conducts extensive experiments on the TCP congestion control protocols, and analyzes the transmission performance of different protocols over 5G millimeter wave links in detail. It will lay a foundation for further research on congestion control protocols suitable for 5G millimeter wave communications.
Research and design of low-power, high-performance processor based on RISC-V instruction set architecture
Authors: GuangTang  , Jiancheng  , Li
Published: May 2022

In embedded IoT applications, in order to meet the needs of small area, low power consumption, and high performance, this paper designs a 32-bit low-power, high-performance microprocessor based on the RISC-V instruction set architecture. It uses a 3-stage pipeline structure with static branch prediction function, supports RV32IM instruction set, and adopts AHB bus as the control bus. The logic function of the processor was verified under the iverilog environment, and the simulation results showed that the processor can run normally. The CoreMark score of 2.38 CoreMark/MHz was measured by running the CoreMark running program, and it supports FreeRTOS transplantation. The analysis and verification results show that the design can be well applied to small-area, low-power embedded application scenarios.
Research on the reliability of Micro LED high-density solder joints under thermal cycling conditions
Authors: Liu Mingyang , Nie Junyang , Liu Yifeng , Sun Jie , Li Min , Yan Chunli , Yan Qun
Published: May 2022

For the purpose of studying the effect of high-density, small-size solder joints on the thermal fatigue life of display devices, a 3D model of the corresponding device structure is established, using finite element analysis methods, and using Anand constitutive equations and Coffin-Manson life prediction models. The equivalent stress and strain change law of an indium solder joint with a diameter of 10 μm under thermal cycling loading conditions is explored, and the key position of the solder joint damage is inferred based on the simulated strain cloud diagram. In addition, the influence of different bump height, bump contact area and Under-Bump Metallization (UBM) thickness on the thermal fatigue life of solder joints is studied separately. The final simulation results show that the location where the solder joint may be damaged first is at the point on the outer side where the solder joint is connected to the UBM on the edge away from the center point. The height of the bump and the contact area of the bump have a significant effect on its thermal fatigue life. In the actual experiment, we should focus on the impact of this aspect.
A low resource consumption Arbiter PUF improved switch component design for FPGA
Authors: Yang Jingfu , Yu Xiaoping , Wei Rikun
Published: May 2022

Aiming at the problems of poor uniqueness and high resource consumption of slice after the implementation of Arbiter physical unclonable function (Arbiter PUF) on field programmable gate array (FPGA), a new improved scheme of switch component structure is proposed. The switch component structure of the improved scheme adopts the parallel-connected mode to improve the uniqueness of the circuit, which avoids the cross-connected mode unable to achieve symmetrical layout on FPGA. At the same time, the improved scheme uses lookup tables to construct the structure of programmable delay line (PDL) with a multiplexer (MUX), which can reduce the internal resource consumption of slice while receiving the same 64-bit challenges. The improved scheme was tested on FPGA boards, the uniqueness and steadiness of different switch component schemes are compared and analyzed, and the feasibility of the improved scheme is verified. The results show that in the generation of Arbiter PUF, compared with the conventional scheme, the improved scheme reduces the resource consumption and improves the uniqueness by 22.2%; Compared with the MUX + MUX scheme, the improved scheme saves 50% of resource consumption while maintaining good uniqueness.
A Design of MIPI DSI Interface for LCD Display Driver
Authors: Liu Yeming , He Chengyue
Published: May 2022

With the development of HD display field, the display interface needs a standard, stable, scalable, low-power, and high-speed solution. Traditional serial interfaces such as TTL, LVDS and RGB have some shortcomings in terms of power and speed. In addition, parallel interfaces need to involve more than 10 channels of signals, and the display-related applications have up to 20 channels. A large number of signals increase the difficulty of wiring, and limit the frequency and transmission distance of the signal, and also restrict the miniaturization of the product, so it has been gradually eliminated by the new technologies. The development direction of the interface technology is mainly low-voltage, high-speed, serial, and miniaturization to meet the demanding requirements of the mobile market for the cost, volume, weight, power consumption, performance and reliability. This paper proposes a solution of serial interface applied to display technology, which is compatible with DPI, DBI and DCS interface. The MIPI DSI receives the pixel information from the host in serial mode. There is an independent protocol in the communication filed, and the interface can support the design of 1080p/60fps display driver.
Strain distribution and electrical characteristics of flexible low-temperature polysilicon thin film transistors under biaxial bending
Authors: Fang ZhiXuan , Huang Zeng , Xie Na , Liu Zheng , Li Dong , Li YiLin , Sun YeRong , Yao ZhiWen
Published: May 2022

This paper investigates the strain distribution of flexible p-channel low temperature polycrystalline silicon thin film transistors under biaxial bending. The strain distribution of LTPS TFTs under different bending conditions is analysed by finite element analysis. 𝛆r and 𝛆θ are essentially equal and constant within the load ring. The finite element analysis shows that when the biaxial bending strain condition is 2.5%, the strain distribution is mainly concentrated at the contact angle between the electrode and the oxide layer. This strain is significantly greater than the overall strain of the device, which is the main reason for the bending performance of the device. We found that under biaxial bending, the threshold voltage shifts towards the negative axis as the biaxial strain increases. Within this strain range, these electrical properties are evident under biaxial strain conditions. Comparing theoretical threshold voltage shifts based on energy band changes with experimental results under biaxial strain, it was found that changes in trap density should also contribute to the threshold voltage shift.
Design of Continuous Class-F Mode Power Amplifier with High Gain Flatness
Authors: Ji Qinmeng , Chen Du , Chen Zehui , Zhao Yongjiu
Published: May 2022

In this letter, a novel RF power amplifier (PA) with high gain flatness and high efficiency operating in continuous Class-F mode is introduced. Since most continuous Class-F PAs can’t meet the requirement of high gain flatness, a new structure which can achieve high gain flatness is presented. A 1.7-2.5GHz PA is designed, which uses CGH40010F GaN device. Simulation results show that the drain efficiency (DE) of the continuous Class-F PA is between 69% and 79%, output power is more than 41dBm across the whole bandwidth. Gain is between 11dB and 11.8dB, and gain flatness is 0.8dB.
A high-range reference voltage low-dropout regulation design for voltage-controlled oscillator circuit
Authors: Song Shengyu , Yuan Hengzhou , Chen Jianjun
Published: May 2022

The stability of VCO as a clock recovery module in high-speed transmission circuits cannot be ignored. The LDO circuit as its power module not only needs to ensure the stability of the VCO under high-speed working conditions, but also needs to satisfy the demand for changes in its supply voltage swing. To meet the above requirements, a high-range reference voltage LDO (Low-dropout Regulator) was designed under the 28nm process. The input of the error amplifier of the LDO adopts a rail-to-rail structure, the reference voltage can be changed in a larger range, and the output voltage can also fluctuate in the range of 0.3V-0.9V. After simulation, the power supply rejection ratio (PSRR) of this LDO is 1.53MHz, the line regulation at full load is 8.29mV/V, the internal noise of the circuit is low, the transient response time from on load to full load is 42ns, and the phase margin is close to 80deg.
Evolution of Silicon Wafer Dimensions
Authors: Peng Jialiang , Liu Anwei , Wang Muyang
Published: May 2022

Solar energy is a renewable energy that the world is endeavouring to utilize. The solar cell is the essential invention that makes energy transfer from light to electricity possible. Solar cells are normally made from silicon wafers due to silicon’s semi-conductivity. The thesis will focus on the development of silicon wafers’ size and fabrication technology. Through analysis of resent (in 5 years) statistics from reports released by government or incorporations, the link between the trend and the reasons behind is interpreted. ITRPV has pointed out that silicon wafers are switching to the mono-crystalline ones, the larger ones, and the PERC processed ones. The mono-crystalline ones excel in efficiency due to uniform lattice structure, but is more costly because of the Czochralski process. The larger cells can absorb more sunlight. The PERC cell technique reduces recombination and reflects unabsorbed sunlight, therefore gradually eliminates the traditional BSF technique.
Automated Quantum Volume Test
Authors: Liu Xiaonan , He Ming , Wang Junchao , Xie Haoshan , Zhao Chenyan
Published: May 2022

As a benchmark for the overall performance of quantum computers, quantum volume has the advantage of being able to reflect the depth of running quantum circuits. But, the quantum volume test code provided by IBM needs to be executed manually, and the simulation result of the quantum simulator is used as the result of the volume test, so that users cannot quickly and accurately test the quantum volume of the actual quantum computer required. In response to this problem, this paper designs an automated quantum volume test program. The program automatically generates quantum volume sequences, selects the number of executions of quantum circuits, and defines real quantum computers to facilitate users to perform quantum volume tests on quantum computers provided by the IBM Quantum Cloud Platform. Simultaneously, according to the automated test program, the quantum volume of IBM’s four small superconducting quantum computers was tested. The test results show that (1) the quantum computer is different, and the qubit layout and execution times ntrials are the same, will cause the quantum volume is uncertain; (2) the same quantum computer, whether ntrials is the same, the robustness of qubit coupling will be affected to a certain extent.
Research on path optimization of electric distribution vehicle with hybrid charging strategy
Authors: Chang Jing , Zhang Qiqian , Zhang Honghai
Published: May 2022

At present, the number of new energy vehicles in China is increasing year by year. In the field of logistics and distribution, new energy vehicles are also showing vigorous vitality. This paper presents a two-stage optimization method for electric vehicle routing problem with hybrid charging strategy. In the first stage, a fuzzy transitive closure method is used to group customer orders, in the second stage, the decision variables and constraints related to the charging strategy are introduced, and a mixed integer linear programming model considering the three charging strategies of fast charging, slow charging and fast switching is constructed, finally, the validity of the proposed model is verified by a instance.
The interference cancellation of non-dispersive UV based on active noise control
Authors: Fan Bo-Qiang , Zhang Yu-Jun , You Kun , He Ying
Published: May 2022

In the process of gas measurement using non-dispersible UV detection technology, the quality of optical signal is directly related to the inversion of concentration. Traditional methods of improving the quality usually processed the detector signal directly, which destroy useful information, and is difficult to eliminate the overall interference of the environment to the detector. The analog circuit system for interference cancellation is designed based on active noise control (ANC) in the paper. The interference channel is added to obtain external noise signal, which through inverting, amplitude and phase adjustment superimposed on the measurement signal by the ANC system, and the digital potentiometer AD5263 is control to optimize by the MCU. The simulation results show that noise standard deviation decrease from 75.16mv to 10.27mv. And the correlation between the processed signal and the NO2 concentration reached 0.99768, which shows the system can be applied suitably in the non-dispersible technology.
Welding defect signal extraction technology based on GAMP-SBL algorithm
Authors: Qi AiLing , Wang JiaSen
Published: May 2022

Flip chip technology has been rapidly developed and widely used in the field of microelectronic packaging, and defect detection has also received more and more attention. Aiming at the problem that noise affects the location and extraction of signal defects in ultrasonic testing, the sparse Bayesian learning based on generalized approximate message passing (GAMP-SBL) algorithm is used to extract signal defects, and the over-complete Gabor dictionary is used to reconstruct signal defects to effectively improve Sparse decomposition algorithm. The precision experiment tested the defect simulation signal and the actual ultrasonic signal respectively, and compared with the greedy algorithm. The experimental results show that the GAMP-SBL algorithm can more effectively extract the defect signal under the noise background.
Research on ultra-tight integrated navigation method based on CKF filtering algorithm
Authors: Zhao Jiafan , Zhao Xin , Li Quanhu , Zhang Jingyu
Published: May 2022

This paper takes the SINS/BDS ultra-tight integrated navigation system as the background of research. Based on the existing integrated navigation nonlinear filtering algorithm, an ultra-tight integrated navigation method based on CKF filtering algorithm is proposed. Compared with the EKF and UKF algorithms, the CKF algorithm reduces the errors caused by intercepting higher order terms in the EKF, overcomes the problem of difficult to determine adjustable parameters in the UKF in practical applications, and greatly reduces the computational effort. Because of the above advantages nowadays the research focus of filtering algorithms is more on CKF algorithm related methods. The EKF, UKF and CKF are applied to the SINS/BDS ultra-tight integrated navigation system for simulation and comparison analysis in order to verify the performance of the algorithm. The simulation results show that the CKF algorithm is an effective and feasible algorithm for integrated navigation method because its stability, filtering accuracy and adaptability are synthetically better than those of the EKF and UKF algorithms.
Text data mining of power based on natural language processing technology
Authors: Wang Xin , Tian Jiming , Li Fei
Published: May 2022

This paper first introduces the development of text mining technology, points out the difficulties of text mining technology, and then designs the power text mining based on natural language processing technology Then it introduces the typical application of text data mining technology in 95598 customer service complaints. Finally, it puts forward the application effect and challenge of power text mining.
A Fuzzy Query Method Oriented to Knowledge Graph
Authors: Liu Yunxing
Published: May 2022

With the widespread application of Knowledge Graphs, Knowledge Graph query technology has received widespread attention. The daily use of natural language usually contains fuzzy terms. The use of fuzzy terms in queries is more in line with natural language habits. Therefore, fuzzy questions have been widely discussed and applied in relational data models, and their use in NoSQL data models has also begun to be affected in recent years. RDF (Resource Description Framework) is a representative model of the knowledge graph, and SPARQL is the standard query language of RDF. To realize the fuzzy query of the knowledge graph, this paper introduces the unclear expansion syntax of aggregate function based on summarizing and analyzing the existing SPARQL fuzzy expansion. Supplements the qualitative preference analysis method then proposes and SPARQL1. 1 Corresponding fuzzy SPARQL1.1 (f-SPARQL1.1) simultaneously provides strategies and techniques for rewriting ambiguous queries into classic SPARQL queries. In addition, this article also provides a visual interface for defining the membership functions of fuzzy terms and provides three interactive methods for setting fuzzy membership functions. Compared with the previous fuzzy query methods for RDF models, the method proposed in this paper has more vital fuzzy query ability and more flexible universality. The experimental results show the usability of the method proposed in this paper.
Scatter correction using FBP with data rearrangement for a single full scan CBCT
Authors: Kang Guanyu , Han Yu , Xi Xiaoqi , Li Lei , Tan Siyu , Zhao Hongfeng , Yan Bin
Published: May 2022

A scattering plate consisting of multiple lead strips is an effective tool for scatter correction and dose reduction in cone-beam CT(CBCT). Existing scattering plate correction methods take advantage of data redundancy by partially blocking cone beam data from a single scan to make up and perform scattering correction. However, for geometric objects with large cone angles during CBCT scans, existing backprojection-filteration(BPF) algorithms cannot accurately reconstruct the object due to data inconsistency and truncation, and may produce additional image artifacts. In order to improve the image quality at large cone angles, this paper proposes a hybrid scatter correction method for filteration-backprojection (FBP) image reconstruction from partially blocked cone beam data using data rearrangement. The proposed method uses a blocker consisting of multiple lead strips that are placed between the light source and the object to provide scatter correction and image reconstruction with beam-blocked data. In combination with a data rearrangement algorithm, the cone-beam projection data is rearranged into a tilted parallel projection data, followed by weighted filtering and inverse projection reconstruction. The experimental results of CBCT show that the proposed method effectively corrects the scattering in each projection and reconstructs the scatter-corrected image from a single scan.
Topology Modeling for Reconfigurable Scan Networks in IEEE 1687 Networks
Authors: Xu Yizhen , Chen Shouhong , Ma Jun , Xu Cuifeng , Zeng Ke
Published: May 2022

This paper designs an automatic generation method of Reconfigurable Scan Networks (RSNs) directed topology model combined with graph theory. By studying IEEE 1687 chains information, RSNs directed topology model is generated automatically based on the interconnections between on-chip instruments and the corresponding internal register length which are determined on standard Instrument Connectivity Language (ICL) script. The test and result analysis demonstrate the feasibility and effectiveness of the technology, which solves the inefficiency and high error rate of RSNs directed topology model built by artificial analyzing ICL script.
Analysis and Measures of Blockage in Submerged Nozzle of Mold large round Bearing Steel
Authors: Wang Weining , Sheng Guangye , Liao Zhiyou , Wang Haichuan , Qiu Shengtao
Published: May 2022

A blockage formed at nozzle of mold during casting of GCr15 bearing steel. The chemical composition and morphology of the nozzle blockage were analyzed by scanning electron microscope/energy dispersive spectrometer and X-ray fluorescence spectrometer. The nozzle blockage was improved by a series of measures such as high carbon tapping, optimization of rapid slag making operation, improvement of slag system, adjustment of static time soft blowing system before casting and tundish and nozzle materials.
Research on the control technology of Ds inclusion and Oxygen content in GCr15 bearing steel
Authors: Li Huicheng , Xie You , Dou Naiyuan , Wang Litao , Jiang Liping
Published: May 2022

This paper presents a method for controlling Ds inclusions and oxygen content in bearing steel produced by EAT-LF-VD-CCM process, including EAF initial refining process, LF external refining process, VD vacuum treatment process and continuous casting production process. By reasonably reducing the basicity of slag, adjusting the amount and sequence of alloy addition, the carbon content of EAF steel is appropriately increased and the temperature of steel extraction is reasonably selected. Optimize the amount of deoxidizer added in off~furnace refining, improve the basicity of refining slag, control the vacuum time, aluminum loss and stirring volume; In the continuous casting process, middle alkaline coating agent, constant drawing speed and protective pouring process are used to control and remove Ds inclusions in bearing steel. The bearing steel produced by this process can remove big sized Ds inclusions in the steel, while the total oxygen content is controlled below 7ppm.
Microstructure and properties of AC-HVAF sprayed B4C/Ni composite coating
Authors: Zhou Bingwen , Wang Chao , Jing Dong , Meng Linggang , Bin Ya , Zhang Huanyue , Zhang Xingguo
Published: May 2022

In industrial application, the service life of TC4 material is easy to be shorten by wear and corrosion. Thus, to improve its surface hardness, wear and corrosion resistance, a process for preparing B4C/Ni coating was proposed, and The microstructure, hardness, wear and corrosion resistance of the coating were studied. The main phases of the composite coating are B4C, Mi3B, Ni3Al2 and C; The porosity of the composite coating is about 2.3%. The average hardness is 591 HV0.3, about 1.7 times of the substrate. In the form of dry friction, the friction coefficient is about 0.41 and the wear rate is 4.997×10-5g-m-1, which is about 20% lower than that of substrate. The corrosion resistance of the coating in 3.5wt.% NaCl solution is significantly improved, its corrosion potential is -0.352V, and corrosion current density is 3.992×10-8 A·cm-2, both are lower than WC coating. Thus, B4C/Ni composite coating prepared by HVAF has high hardness, good wear and corrosion resistance.
Simulation analysis of SR motor speed regulation system based on PI control
Authors: Zhang Chenbo , Chen Kai , Yu Jun , Zhang Qian , Huo Chunrun
Published: May 2022

The switching reluctance motor speed regulation system (SRD) will produce more serious nonlinear problems when running, and the current conventional solution is analyzed and discussed as a PI control method(HE 2008). Based on the SR motor model included in Matlab/Simuliunk simulation system, the simulation results are obtained by using the comparison method with or without PI control, and the advantages and disadvantages of the PI control method are analyzed to achieve the requirements for the switched reluctance motor control system.
Plasmon gain in HgTe/CdHgTe multi-quantum-well heterostructures
Authors: Rudakov A O , Ya Aleshkin V , Gavrilenko V I
Published: May 2022

The work is devoted to the theoretical study of plasmon gain in HgTe/CdHgTe multi-quantum-well heterostructures. The spectra of plasmons and plasmon gain are found in structures with 2–8 quantum wells (QWs) under the condition of inverse band population. A nonmonotonic increase in the plasmon gain with an increase in the number of QWs is shown. The dependence of the threshold concentration of nonequilibrium carriers for stimulated plasmon emission on the number of QWs in structures with 1–8 QWs has been studied.
Dynamic characteristics of composite coronary stents after implantation
Authors: Chen Yanan , Shang Xinchun
Published: May 2022

The dynamic characteristics of composite coronary stents of poly-l-lactic acid (PLLA) coated magnesium (Mg) alloy were investigated using the finite element method (FEM). Firstly, the effects on dynamic performances of stents were considered, such as stent materials, large deformation of expansion and springback during stent implantation, residual stress after implantation, degradation of PLLA coating, and vascular constraints. Secondly, variations in the dynamic characteristics of the blocked artery after stent implantation were calculated. The natural frequencies and corresponding vibration modes of stents and arteries, as well as the response under harmonic excitation were numerically simulated. The results show that, the natural frequency of the composite stent is much smaller than that of the Mg alloy stent. Each natural frequency of the stent after a large deformation of expansion and springback significantly decreased compared with that of the initial stent. The existence of residual stress has a minor effect on the natural frequencies of the stent and does not change the vibration modes. However, degradation of the PLLA coating and vascular elastic constraint have distinct influences on the frequencies of stents. Modal analysis results indicate that bending, torsional and breathing modes occur in the first five vibration modes. Moreover, there are differences in the natural frequencies and vibration modes among healthy, blocked and stent-implanted arteries. These results are helpful for understanding the dynamic behavior of the vascular system after stent implantation and have guiding significance in stent design.
Thulium oxides supported on MnCeTiOX catalysts for low-temperature NH3-SCR of NOX
Authors: Lv Shuyi , Huang Jian , Chen Yue , Zhang Qiyao , Huang Yongmin
Published: May 2022

In this work, the MnCeTiOX catalyst was prepared by sol-gel method and doped with thulium (Tm), which improved its low-temperature selective catalytic reduction (SCR) activity and resistance to SO2 poisoning. In this paper, the surface properties of Tm-doped MnCeTiOX catalysts were studied and analysed by means of BET, XRD, SEM, NH3-TPD, H2-TPR and XPS. The catalyst performance was tested by using simulated flue gas. The results show that Tm doping can effectively inhibit the crystallization degree of TiO2, increase the catalyst specific surface area, and make the elements distribute more uniformly on the catalyst surface. Meanwhile, the amount of Brønsted acid sites could be increased by Tm doping. It also increased the concentration of surface adsorbed oxygen and the ratio of Mn4+/Mn and Ce3+/Ce. Therefore, the activity of the catalyst was improved by Tm doping in the temperature range of 90 °C to 270 °C, the catalyst activity remained above 97% in the temperature range of 180 °C to 270 °C. And the catalyst activity remained above 88% after a 10 h-SO2 poisoning test. Tm doping could effectively inhibit SO2 poisoning of the catalyst and reduce the adsorption of SO2 on the catalyst surface.
Theta functions on varieties with effective anti-canonical class
Authors: Gross Mark , Hacking Paul , Siebert Bernd
Published: May 2022

We show that a large class of maximally degenerating families of

n
n

-dimensional polarized varieties comes with a canonical basis of sections of powers of the ample line bundle. The families considered are obtained by smoothing a reducible union of toric varieties governed by a wall structure on a real

n
n

-(pseudo-)manifold. Wall structures have previously been constructed inductively for cases with locally rigid singularities [Gross and Siebert, From real affine geometry to complex geometry (2011)] and by Gromov-Witten theory for mirrors of log Calabi-Yau surfaces and

K
3

K3

surfaces [Gross, Pandharipande and Siebert, The tropical vertex; Gross, Hacking and Keel, Mirror symmetry for log Calabi-Yau surfaces (2015); Gross, Hacking, Keel, and Siebert, Theta functions and

K
3

K3

surfaces (In preparation)]. For trivial wall structures on the

n
n

-torus we retrieve the classical theta functions.

We anticipate that wall structures can be constructed quite generally from maximal degenerations. The construction given here then provides the homogeneous coordinate ring of the mirror degeneration along with a canonical basis. The appearance of a canonical basis of sections for certain degenerations points towards a good compactification of moduli of certain polarized varieties via stable pairs, generalizing the picture for K3 surfaces [Gross, Hacking, Keel, and Siebert, Theta functions and

K
3

K3

surfaces (In preparation)]. Another possible application apart from mirror symmetry may be to geometric quantization of varieties with effective anti-canonical class.
Type II Blow Up Solutions with Optimal Stability Properties for the Critical Focussing Nonlinear Wave Equation on ℝ³⁺¹
Authors: Burzio Stefano , Krieger Joachim
Published: May 2022

We show that the finite time type II blow up solutions for the energy critical nonlinear wave equation
\[

◻

u
=
−

u
5

\Box u = -u^5

\]
on

R

3
+
1

\mathbb {R}^{3+1}

constructed in Krieger, Schlag, and Tartaru (“Slow blow-up solutions for the

H
1

(

R

3

)

H^1(\mathbb {R}^3)

critical focusing semilinear wave equation”, 2009) and Krieger and Schlag (“Full range of blow up exponents for the quintic wave equation in three dimensions”, 2014) are stable along a co-dimension one Lipschitz manifold of data perturbations in a suitable topology, provided the scaling parameter

λ
(
t
)
=

t

−
1
−
ν

\lambda (t) = t^{-1-\nu }

is sufficiently close to the self-similar rate, i. e.,

ν
>
0

\nu >0

is sufficiently small. This result is qualitatively optimal in light of the result of Krieger, Nakamishi, and Schlag (“Center-stable manifold of the ground state in the energy space for the critical wave equation”, 2015). The paper builds on the analysis of Krieger and Wong (“On type I blow-up formation for the critical NLW”, 2014).
Decorated Dyck Paths, Polyominoes, and the Delta Conjecture
Authors: D’Adderio Michele , Iraci Alessandro , Vanden Wyngaerd Anna
Published: May 2022

We discuss the combinatorics of decorated Dyck paths and decorated parallelogram polyominoes, extending to the decorated case the main results of both Haglund (“A proof of theq,tq,t-Schröder conjecture”, 2004) and Aval et al. (“Statistics on parallelogram polyominoes and aq,tq,t-analogue of the Narayana numbers”, 2014). This settles in particular the cases⟨⋅,en−dhd⟩\langle \cdot ,e_{n-d}h_d\rangleand⟨⋅,hn−dhd⟩\langle \cdot ,h_{n-d}h_d\rangleof the Delta conjecture of Haglund, Remmel and Wilson (“The delta conjecture”, 2018). Along the way, we introduce some new statistics, formulate some new conjectures, prove some new identities of symmetric functions, and answer a few open problems in the literature (e.g., from Aval, Bergeron and Garsia [2015], Haglund, Remmel and Wilson [2018], and Zabrocki [2019]). The main technical tool is a new identity in the theory of Macdonald polynomials that extends a theorem of Haglund in “A proof of theq,tq,t-Schröder conjecture” (2004).
Parametric estimation for functional autoregressive processes on the sphere
Authors: Caponera A. , Durastanti C.
Published: May 2022

The aim of this paper is to define a nonlinear least squares estimator for the spectral parameters of a spherical autoregressive process of order 1 in a parametric setting. Furthermore, we investigate on its asymptotic properties, such as weak consistency and asymptotic normality.
Stationary solutions of a second-order differential equation with operator coefficients
Authors: Horodnii M.
Published: May 2022

Necessary and sufficient conditions are given for the existence of a unique stationary solution to the second-order linear differential equation with bounded operator coefficients, perturbed by a stationary process. In the case when the corresponding “algebraic” operator equation has separated roots, the new representation of the stationary solution of the considered differential equation is obtained.
Gabapentin initiation in the inpatient setting: A characterization of prescribing
Authors: Waterloo Marissa , Rozic Matthew , Knauss Gionna , Jackson Simran , Karuga Dellon , Zimmerman David E , Montepara Courtney A , Covvey Jordan R , Nemecek Branden D
Published: May 2022

Purpose

Gabapentin is a widely prescribed analgesic with increased popularity over recent years. Previous studies have characterized use of gabapentin in the outpatient setting, but minimal data exist for its initiation in the inpatient setting. The objective of this study was to characterize the prescribing patterns of gabapentin when it was initiated in the inpatient setting.

Methods

This was a retrospective cohort study of a random sample of adult patients who received new-start gabapentin during hospital admission. Patients for whom gabapentin was prescribed as a home medication, with one-time, on-call, or as-needed orders, or who died during hospital admission were excluded. The primary outcome was characterization of the gabapentin indication; secondary outcomes included the starting and discharge doses, the number of dose titrations, the rate of concomitant opioid prescribing, and pain clinic follow-up. Patients were stratified by surgical vs nonsurgical status.

Results

A total of 464 patients were included, 283 (61.0%) of whom were surgical and 181 (39.0%) of whom were nonsurgical. The cohort was 60% male with a mean (SD) age of 56 (18) years; surgical patients were younger and included more women. The most common indications for surgical patients were multimodal analgesia (161; 56.9%), postoperative pain (53; 18.7%), and neuropathic pain (26; 9.2%), while those for nonsurgical patients were neuropathic pain (72; 39.8%) and multimodal analgesia (53; 29.3%). The mean starting dose was similar between the subgroups (613 mg for surgical patients vs 560 mg for nonsurgical patients; P = 0.196). A total of 51.6% vs 81.8% of patients received gabapentin at discharge (P < 0.0001), while referral/follow-up to a pain clinic was minimal and similar between the subgroups (1.1% vs 3.9%; P = 0.210).

Conclusion

Inpatients were commonly initiated on gabapentin for generalized indications, with approximately half discharged on gabapentin. Further studies are needed to assess the impact of this prescribing on chronic utilization.
Development of a pharmacist-managed protocol for the transition from intravenous to subcutaneous insulin in critically ill adults
Authors: Gerhardt Jenna M , Dine Serena A , Foster David R , Lodolo Andrew C , McIntire Allyson M , Peters Michael J , Rhew Taylor A , Walroth Todd A
Published: May 2022

Purpose

To evaluate the efficacy and safety of a pharmacist-managed protocol for transitioning critically ill patients from intravenous (IV) to subcutaneous insulin.

Methods

This single-center, retrospective, observational study included patients admitted to the medical or surgical/trauma intensive care unit who received a continuous infusion of IV insulin from January 2019 to April 2021. Patients were excluded if they were less than 18 years old, pregnant, or incarcerated or received IV insulin for the diagnosis of diabetic ketoacidosis, hyperglycemic hyperosmolar state, calcium channel blocker or β-blocker overdose, or hypertriglyceridemia. The primary outcome was to evaluate the percentage of blood glucose (BG) concentrations within the target range of 70 to 150 mg/dL within 48 hours of the transition to subcutaneous insulin. Secondary outcomes included the percentage of BG concentrations within the goal range following transition at 0 to 12 hours and 12 to 24 hours, the incidence of hypo- and hyperglycemia, and the percentage of patients requiring dose adjustments after the initial transition.

Results

Pharmacists were able to achieve BG concentrations in the target range for 53% of transitions at 12 hours, 40% of transitions at 24 hours, and 47% of transitions at 48 hours. With respect to safety endpoints, the pharmacist-managed group had a low rate of hypoglycemia (1.0%) and no severe hypoglycemia. Hyperglycemia was reported for 28% of BG concentrations while severe hyperglycemia was reported for 27%. Pharmacists transitioned patients to an average of 63% of the 24-hour total daily dose of insulin as basal insulin.

Conclusion

Pharmacists can effectively and safely transition critically ill patients from IV to subcutaneous insulin utilizing a standardized protocol.
Adjusting vasopressin availability and formulation: A cost-savings initiative
Authors: Sizemore Summer , Patel Megan Van Berkel , Carter Breanna , Garrett Emily
Published: May 2022

Purpose

The increase in vasopressin price has required many healthcare systems to consider cost-saving strategies. To combat rising medication costs, our institution changed formulations from 50 units/250 mL to 20 units/100 mL and removed vasopressin from automated dispensing cabinets (ADCs).

Methods

This retrospective review occurred at a 545-bed academic medical center with 97 adult intensive care unit beds. Adult patients receiving a continuous vasopressin infusion were included with no exclusion criteria. A 1-month period was assessed before and after changing the formulation (pre and post groups, respectively). Duplicate bags compounded by pharmacy and bedside teams were also assessed in the pre group. The primary outcome was the estimated annual cost savings due to formulation change with a secondary outcome of estimated annual cost savings due to removal of vasopressin from ADCs. Each 20-unit vial of vasopressin cost $183.21 (wholesale acquisition cost) at the time of the study.

Results

In the pre group, 39 patients requiring a vasopressin infusion were allocated an average of 2 bags each costing $1,099.26 per patient. In the post group, 41 patients required an average of 4 bags each costing $732.84 per patient. With respect to the primary outcome, a savings of $366.42 per patient and an average of 40 patients per month would lead to an annual cost savings of $175,881.60. Secondary outcome analysis identified 9 duplicate bags prepared in the pre group; therefore, removal of vasopressin from ADCs is estimated to provide additional cost savings of $59,360.04. The estimated annual cost savings from both initiatives is $235,241.64.

Conclusion

Changing the vasopressin formulation and removing it from ADCs resulted in a significant cost savings to the health system.
Evaluation of the safety of a novel peripheral vasopressor pilot program and the impact on central line placement in medical and surgical intensive care units
Authors: Marti Kristen , Hartley Christopher , Sweeney Elizabeth , Mah John , Pugliese Nicholas
Published: May 2022

Purpose

The purpose of this quality improvement project was to evaluate the safety and feasibility of peripheral vasopressor administration in an attempt to minimize the placement and improve early removal of unnecessary central lines to reduce central line–associated bloodstream infection (CLABSI) rates.

Methods

A retrospective chart review was conducted on patients who received vasopressors via peripheral infusion over 3 months, starting at the time of guideline implementation.

Results

We identified 129 vasopressor orders among 79 patients that were administered peripherally. Among these orders, 3 events were documented as possible extravasation events. Forty-five patients (57%) did not require central line placement due to increasing vasopressor requirements. Standard utilization ratio data suggest minimal central line impact of the protocol implementation. December 2020 to February 2021 was associated with a large second peak of coronavirus disease 2019 (COVID-19) in our region. Utilization of central lines was less than predicted in December 2020 to February 2021 in 2 of our 3 intensive care units (ICUs); however, the differences were statistically significant on only 3 occasions. In the third ICU, utilization was greater than predicted, but this unit housed a majority of the most critically ill patients with COVID-19.

Conclusion

This study suggests that short-term use of select vasopressors at conservative doses is safe for peripheral administration and points toward efficacy at preventing central line placement. Further analysis is required to confirm efficacy.
HPiP: an R/Bioconductor package for predicting host–pathogen protein–protein interactions from protein sequences using ensemble machine learning approach
Authors: Rahmatbakhsh Matineh , Moutaoufik Mohamed Taha , Gagarinova Alla , Babu Mohan
Published: May 2022

Motivation

Despite arduous and time-consuming experimental efforts, protein–protein interactions (PPIs) for many pathogenic microbes with their human host are still unknown, limiting our understanding of the intricate interactions during infection and the identification of therapeutic targets. Since computational tools offer a promising alternative, we developed an R/Bioconductor package, HPiP (Host–Pathogen Interaction Prediction) software with a series of amino acid sequence property descriptors and an ensemble machine learning classifiers to predict the yet unmapped interactions between pathogen and host proteins.

Results

Using severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) or the novel SARS-CoV-2 coronavirus-human PPI training sets as a case study, we show that HPiP achieves a good performance with PPI predictions between SARS-CoV-2 and human proteins, which we confirmed experimentally in human monocyte THP-1 cells, and with several quality control metrics. HPiP also exhibited strong performance in accurately predicting the previously reported PPIs when tested against the sequences of pathogenic bacteria, Mycobacterium tuberculosis and human proteins. Collectively, our fully documented HPiP software will hasten the exploration of PPIs for a systems-level understanding of many understudied pathogens and uncover molecular targets for repurposing existing drugs.

Availability and implementation

HPiP is released as an open-source code under the MIT license that is freely available on GitHub (https://github.com/BabuLab-UofR/HPiP) as well as on Bioconductor (http://bioconductor.org/packages/devel/bioc/html/HPiP.html).

Supplementary information

Supplementary data are available at Bioinformatics Advances online.
ScisorWiz: visualizing differential isoform expression in single-cell long-read data
Authors: Stein Alexander N , Joglekar Anoushka , Poon Chi-Lam , Tilgner Hagen U
Published: May 2022

RNA isoforms contribute to the diverse functionality of the proteins they encode within the cell. Visualizing how isoform expression differs across cell types and brain regions can inform our understanding of disease and gain or loss of functionality caused by alternative splicing with potential negative impacts. However, the extent to which this occurs in specific cell types and brain regions is largely unknown. This is the kind of information that ScisorWiz plots can provide in an informative and easily communicable manner. ScisorWiz affords its user the opportunity to visualize specific genes across any number of cell types, and provides various sorting options for the user to gain different ways to understand their data. ScisorWiz provides a clear picture of differential isoform expression through various clustering methods and highlights features such as alternative exons and single-nucleotide variants. Tools like ScisorWiz are key for interpreting single-cell isoform sequencing data. This tool applies to any single-cell long-read RNA sequencing data in any cell type, tissue or species.

Availability and implementation

Source code is available at http://github.com/ans4013/ScisorWiz. No new data were generated for this publication. Data used to generate figures was sourced from GEO accession token GSE158450 and available on GitHub as example data.
PeakBot: machine-learning-based chromatographic peak picking
Authors: Bueschl Christoph , Doppler Maria , Varga Elisabeth , Seidl Bernhard , Flasch Mira , Warth Benedikt , Zanghellini Juergen
Published: May 2022

Motivation

Chromatographic peak picking is among the first steps in data processing workflows of raw LC-HRMS datasets in untargeted metabolomics applications. Its performance is crucial for the holistic detection of all metabolic features as well as their relative quantification for statistical analysis and metabolite identification. Random noise, non-baseline separated compounds and unspecific background signals complicate this task.

Results

A machine-learning-based approach entitled PeakBot was developed for detecting chromatographic peaks in LC-HRMS profile-mode data. It first detects all local signal maxima in a chromatogram, which are then extracted as super-sampled standardized areas (retention-time versus m/z). These are subsequently inspected by a custom-trained convolutional neural network that forms the basis of PeakBot’s architecture. The model reports if the respective local maximum is the apex of a chromatographic peak or not as well as its peak center and bounding box. In training and independent validation datasets used for development, PeakBot achieved a high performance with respect to discriminating between chromatographic peaks and background signals (accuracy of 0.99). For training the machine-learning model a minimum of 100 reference features are needed to learn their characteristics to achieve high-quality peak-picking results for detecting such chromatographic peaks in an untargeted fashion. PeakBot is implemented in python (3.8) and uses the TensorFlow (2.5.0) package for machine-learning related tasks. It has been tested on Linux and Windows OSs.

Availability and implementation

The package is available free of charge for non-commercial use (CC BY-NC-SA). It is available at https://github.com/christophuv/PeakBot.

Supplementary information

Supplementary data are available at Bioinformatics online.
The impact of phosphorylated PTEN at threonine 366 on cortical connectivity and behaviour
Authors: Ledderose Julia M T , Benitez Jorge A , Roberts Amanda J , Reed Rachel , Bintig Willem , Larkum Matthew E , Sachdev Robert N S , Furnari Frank , Eickholt Britta J
Published: May 2022

The lipid phosphatase PTEN (phosphatase and tensin homologue on chromosome 10) is a key tumour suppressor gene and an important regulator of neuronal signalling. PTEN mutations have been identified in patients with autism spectrum disorders, characterized by macrocephaly, impaired social interactions and communication, repetitive behaviour, intellectual disability, and epilepsy. PTEN enzymatic activity is regulated by a cluster of phosphorylation sites at the C-terminus of the protein. Here, we focused on the role of PTEN T366 phosphorylation and generated a knock-in mouse line in which Pten T366 was substituted with alanine (PtenT366A/T366A). We identify that phosphorylation of PTEN at T366 controls neuron size and connectivity of brain circuits involved in sensory processing. We show in behavioural tests that PtenT366/T366A mice exhibit cognitive deficits and selective sensory impairments, with significant differences in male individuals. We identify restricted cellular overgrowth of cortical neurons in PtenT366A/T366A brains, linked to increases in both dendritic arborization and soma size. In a combinatorial approach of anterograde and retrograde monosynaptic tracing using rabies virus, we characterize differences in connectivity to the primary somatosensory cortex of PtenT366A/T366A brains, with imbalances in long-range cortico-cortical input to neurons. We conclude that phosphorylation of PTEN at T366 controls neuron size and connectivity of brain circuits involved in sensory processing and propose that PTEN T366 signalling may account for a subset of autism-related functions of PTEN.