bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of forming limit curve for AA6061-T6 at room and elevated temperatures
Authors: Kacem Ahmed , Laurent Hervé , Thuillier Sandrine
Published: May 2022

Forming Limit Curve (FLC) has been widely adopted as a practical criterion for evaluating the formability of sheet metals. Predicting a reliable FLC by a virtual methodology could lead to robust process optimization before expensive tool manufacturing. In order to increase the predictive capabilities of the virtual forming tools, an accurate modeling of the forming limit curve should be considered at room and elevated temperatures. In this work, the isothermal forming limit curves of 6000 series aluminum alloy sheet metal are predicted by performing numerical simulations of Nakajima test. A stress triaxiality and Lode angle based ductile fracture criterion is used to determine the forming limit curve. Also, the ductile fracture criterion is extended to add the impact of temperature on ductile fracture prediction. The hybrid experimental-numerical approach is used to calibrate the ductile fracture criterion. The forming limit curve of AA6061-T6 sheet metal, with a thickness of 1 mm, is predicted using the calibrated ductile fracture criterion at room and elevated temperatures. Numerical simulations are performed in 3D with the finite element code Abaqus. The limit strains are determined for specimens undergoing deformation under different strain paths. Influence of temperature on the predicted forming limit curve is discussed.
An alternative time-based strategy for the evaluation of forming limits using optical experimental measurements
Authors: Karadogan Celalettin , Görz Marcel , Liewald Mathias , Bühler Marco
Published: May 2022

Optical measuring systems allow to observe the sheet metal instability more precisely. The section method was first standardised and made available in commercial measurement systems in order to evaluate the forming limit curves almost automatically. The insignificant contribution of the necking area to the evaluated critical strains compared to the neighbouring volume of material led to alternative approaches such as the time-based evaluation criteria. The majority of these criteria take into account the strain evolution at the material necking location and are also suitable for evaluating other types of limits such as edge-crack sensitivity. Some advanced high-strength steels typically exhibit very short deformation after the onset of instability, which complicates the application of time-based approaches because they require sufficient amount of deformation after necking. The proposed approach is an attempt to reduce the dependence of the time-based approaches on the amount of deformation after necking by taking into account the local characteristics of the measurement curves. The approach is applied to some advanced high-strength steels to evaluate the forming instability and edge-crack sensitivity. The superiority of this identification approach is demonstrated in this paper by comparison with classical time-based approaches.
Axisymmetric V-Bending of Sheet Metal: Determining the Fracture Strain and the Weakest Material Direction for Plane Strain Tension in One Test
Authors: Beerli T , Grolleau V , Mohr D , Roth C C
Published: May 2022

Plane strain tension is one of the most critical loading conditions leading to ductile failure in forming and crash applications. Hence knowing the fracture strain and weakest orientation for this stress state is crucial for safe design. A novel axisymmetric V-bending experiment is proposed to identify the strain to fracture and the weakest sheet material orientation for plane strain tension under proportional loading. After clamping its inner and outer boundaries, a disc-shaped specimen with an annular gage section is bent over a tubular knife of diameter 54mm. A single camera takes images of the top surface of the specimen throughout the experiment. It allows for timely crack detection and digital image correlation-based strain measurements. Experiments are performed on a range of modern engineering materials comprising two aluminium alloys (AA7075 and AA6014) as well as two steels (DP1180 and CR4). The experiments are complemented by Finite Element simulations to assess the robustness of the novel experimental approach.
Hot tensile and expansion tests of Ductibor®1000 steel
Authors: Demazel N , Boyer A , Laurent H , Oliveira M C
Published: May 2022

The boron steels present high mechanical properties which are of great interest for lightening the vehicle parts. But these steels, as the Ductibor®1000, need to be hot formed. The hot stamping process consists of a heating/austenization step leading to an increase of the formability, followed by simultaneous forming and quenching steps. In order to understand the thermomechanical and metallurgical cycles occurring during this process, this study focuses on two different test devices at high temperatures using direct resistance heating: a Gleeble 3500 machine for tensile tests and a new bulge test device. The two different tests were performed on the Ductibor®1000 steel for a temperature of 900°C (with temperature holding during deformation) after an austenization step, which consists of heating up to 900°C and a temperature holding stage. The stress-strain curves of the tensile tests obtained using Digital Image Correlation (DIC) are compared to the stress-strain curves of the bulge tests obtained using a laser profilometer and the membrane theory.
A relative approach for uncertainty quantification of inversely identified material behavior using a heterogeneous test for sheet metal
Authors: Conde M , Coppieters S , Andrade-Campos A
Published: May 2022

The process of calibrating the material parameters of a constitutive model has inherent uncertainty sources. These can lead to inadequate material behavior characterization and, consequently, errors in the numerical simulations. A robust mechanical test is necessary for accurate material mechanical characterization. In this work, it is relatively quantified the uncertainties of the parameter identification of the Swift hardening law and the Yld2000-2d yield function using Digital Image Correlation (DIC) and a DIC-levelled approach. The levels of uncertainty are calculated with a derivative-based local method, having into consideration the Karush-Kuhn-Tucker (KKT) conditions for optimization problems. The mechanical test used for the parameter calibration was an optimized interior notched specimen that presents several strain and stress states simultaneously. The synthetic images were generated based on the numerical data, and the strain fields were accessed using DIC techniques. It was concluded that the step size is the DIC parameter that most influences the material parameter identification.
Characterization of elasto-plastic transition of sheet metal by using large-scale four-point bending test
Authors: Liegard W , Tabourot L , Balland P
Published: May 2022

The elastic properties of a material do play an important role in the spring back behaviour of sheet metal and have a dominant influence on the depth of where the bending tool has to go. In industry, the elastic behaviour is often approximated to a pure linear behaviour defined by two coefficients: Young’s modulus (E) and yield stress (Re). This modelling hypotheses result in geometrical errors in the angle and flange lengths of bended part. In order to better determine material behaviour at very small strains, a large-scale four-point bending test machine is presented in this study. Generating pure bending and measuring the residual radius allow observation of the transition between elastic and plastic deformation behaviour. By deforming the test beam in the supposed pure elastic area, it appears that the pure elasticity behaviour of the material is indeed non-existent. Plastic strains can be detected as soon as the very first bending of the sample, at very low equivalent stress well under usual accepted elastic yield stresses. Perspectives are addressed in order to solve this difficulty, which hinders the possibility of correctly simulating the bending process, particularly with regard to tight geometry requirements.
On the use of the Gleeble® test as a heterogeneous test: sensitivity analysis on temperature, strain and strain rate
Authors: Coelho B. , Thuillier S.
Published: May 2022

The development of hot and warm forming processes for the manufacture of complex-shaped alloy components has been increasing. At the same time, the knowledge of the effect of certain variables involved in such processes such as temperature and strain rate is essential for an accurate modelling of the materials and processes. This work provides a sensitivity study on the effect of different testing conditions variables on beta titanium-molybdenum (Ti-Mo) alloys. Data from quasi-static uniaxial tensile tests performed on a dog bone shaped specimen using a Gleeble® machine is post-processed with Aramis digital image correlation (DIC) software and numerical models of the tests are developed using Abaqus® finite element analysis (FEA) software. Results considering different temperature conditions, different applied strain rates and different gauge lengths for the determination of the mechanical properties of the material are discussed.
On the inverse identification methods for forming plasticity models using full-field measurements
Authors: Andrade-Campos A , Bastos N , Conde M , Gonçalves M , Henriques J , Lourenço R , Martins J M P , Oliveira M G , Prates P , Rumor L
Published: May 2022

The simulation of deep drawing processes and its quality is intrinsically dependent on the accuracy of the constitutive model in reproducing the mechanical behaviour of the sheet metal material. Today, the calibration of elastoplastic models – correspondent to the inverse identification of the material parameters – often uses full-field measurements, through Digital Image Correlation (DIC) techniques, to capture non-homogeneous strain fields and states, coupled with non-straightforward numerical inverse methodologies. In the last decade, new parameter identification methodologies, such as the Finite Element Model Updating (FEMU), the Constitutive Equation Gap (CEG) method, the Equilibrium Gap Method (EGM) and the Virtual Fields Method (VFM) have been developed and have proven to be effective for non-linear plasticity models. Nonetheless, the FEMU and the VFM have distinguished themselves from the others. More recently, supervised Machine Learning (ML) techniques have been also used as an inverse identification method. These artificial intelligence-based methods use large datasets of numerical tests to train an inverse model in which the input is the history of the strain field and loads during the test, and the output are directly the material parameters.

The goal of this paper is to analyse, compare and discuss these inverse identification methods, with particular focus on the FEMU, VFM, and ML methodologies. A heterogeneous tensile-load test is considered to compare in detail the FEMU, VFM, and ML strategies.
Analysis of Distributed-Ledger-Technology for the Exchange of Design, Production and Simulation Data in Roll Forming
Authors: Kohl B , Krüger M , Dietl T , Lechner M , Trunzer E , Merklein M , Sedlmaier A , Vogel-Heuser B
Published: May 2022

Digitalization in the metal forming industry needs to be improved to achieve the goals set by Industrie 4.0. Distributed-Ledger-Technology (DLT) has been identified as a promising foundation for tackling the underlying problem of consistent information exchange. DLT-based solutions have already been developed, but none explicitly covers the roll forming use-case. This paper presents a Hyperledger-Fabric-based blockchain network to fill this research gap. This network is specifically designed for the roll forming industry, while still aiming to meet general information exchange requirements. The roll forming use-case is divided into the material supply chain and a design/simulation workflow. Participants and parameters in these two data transfer chains have been validated with the help of industry experts. Running the conceptualized network on an on-premise server has allowed for a detailed evaluation. Feedback provided by experts of the roll forming industry shows the potential of the presented network. Furthermore, the presented solution covers requirements often neglected by existing approaches like large data handling, compatibility to existing interfaces, secure communication, and access rights definition. In summary, this paper provides a pioneering implementation and evaluation of a DLT-based solution for the roll forming industry and, therefore, a foundation for the next steps towards Industrie 4.0.
Automatic generation of 3d spiral tool path for incremental sheet metal forming of mechanical parts with complex geometry
Authors: Frikha Sirine , Giraud-Moreau Laurence , Bouguecha Anas , Haddar Mohamed
Published: May 2022

Incremental sheet metal forming is a flexible manufacturing technology that allows to form of various components on the same milling machine, without expensive tools. A hemispherical tool moves along a CNC-controlled tool path and deforms the sheet into the desired shape. The tool path has a significant role in the geometric accuracy of the final part. There has been very little research on the problem of the forming of sophisticated parts with asymmetric wall angles. This paper presents a new approach to generating optimized tool paths for single-point incremental sheet forming (SPIF). At first, a strategy is proposed for the automatic generation of a 3D tool path during forming in a single-step operation. Then, a systematic technique of creating intermediate shapes is investigated by defining tool paths interpolated from the final part shape. The proposed methodology is applied to form a hip cup prosthesis. This part has a complex asymmetric geometry with important angles, a multi-step approach is used. The proposed methodology to define the different tool paths was implemented in Matlab. A numerical simulation of the incremental forming process is performed to predict the final geometry of the aluminum sheet. A comparison of desired and predicted geometries shows the reliability of the proposed method.
Springback inhibition of Ti-6Al-4V sheet with impact hydroforming at room temperature
Authors: Li H , Xu Y , Chen S F , Song H W , Zhang S H
Published: May 2022

Springback is a tough issue in sheet forming, and always leads to dimensional inaccuracy of formed parts. Titanium alloy selected as desired light-weight alloy has been playing significant roles in aerospace industry because of its good comprehensive performance. Whereas, titanium alloy components manufactured always exhibit severe springback at room temperature, which greatly restrict their application. To explore the possibility of reducing springback, rectangular lath-shaped parts with Ti-6Al-4V alloy sheet were fabricated by impact hydroforming (IHF) with self-designed equipment. Consequently, much lower springback is obtained using IHF with high strain rate than that formed by conventional stretch-bending with low strain rate. Great efforts are paid to clarify the mechanism of springback restriction under IHF. Different from traditional forming methods, more complex and high-speed interaction behavior between liquid and Ti-6Al-4V alloy sheet occurs. It considerably increases the difficulty for analyzing the deformation process of sheet under IHF. Thus, a novel solid-liquid coupling numerical simulation technology for IHF was developed. To validate the simulation accuracy, experiments with different forming processes and parameters were performed. Given the combined analysis of experimental and simulation results, it is found that distinctive forming paths are introduced between stretch-bending and IHF. Specifically, the preferred deformation region of sheet transfers from middle region for conventional stretch-bending to end regions under IHF, which mainly attributes to the unique loading behavior of liquid at high strain rate.
Understanding the influence of servo-press kinematics on a sheet metal forming process using a simulation-based approach
Authors: Burlat M , Maillard A
Published: May 2022

The capabilities offered by the servo-presses are not fully exploited by the sheet metal forming companies due to the lack of knowledge of their influence on the forming processes. Indeed, the control of the beneficial effects and the full use of servo-press features, such as the programmable kinematics, are increasingly becoming concerns for the companies having acquired that type of press. In this context, the finite element simulation is undoubtedly an approach to evaluate the potential gains generated by those presses and to validate the servo-press kinematics.

This study is an attempt to gain insight into the impact of servo-press kinematics on a sheet metal forming feasibility. The forming experiments presented in this study have been carried out by CETIM for a X2CrNi18-09 stainless steel. The numerical simulation has been performed with AutoForm software that enables the user to rapidly and accurately design and simulate the sheet metal forming processes, including stamping operations. All parameters influencing the stamping operation in a servo-press can be considered. They include, for example, press kinematics, sheet temperature variation during the forming process and of course material mechanical properties. The hardening curves of the studied stainless steel at different strain rates and different temperatures have been taken into account. The simulation has been carried out for two servo-press kinematics: sinusoidal and soft-touch. The feasibility criterion, i.e. the part drawing depth, has been defined to match the experimental results. The numerical simulation with AutoForm made it possible to highlight the thermal effects, in particular, the maximum temperatures reached during the drawing operation. The simulation results analysis allowed the user to optimize the motion curve of the press in order to have a minimum cycle time while respecting the lowest possible temperature the sheet might reach during a drawing operation. Thanks to this study, the sheet metal forming companies will therefore benefit from this technology to develop and optimize the servo-presses usage.
A novel incremental sheet metal forming process for long and open section profiles
Authors: Essa A , Abeyrathna B , Rolfe B , Weiss M
Published: May 2022

Complex components from High Strength Steel (HSS) can be formed with Flexible Roll Forming (FRF). However, flange wrinkling limits the part shape complexity that can be achieved and hence limits its application in the automotive industry. A novel forming technology is introduced in this study, Incremental Shape Rolling (ISR), where a pre-cut blank is clamped between a top and bottom die and then a single forming tool incrementally forms the material according to the bottom die’s geometry. It is believed that ISR can significantly reduce the wrinkling issue compared to FRF. In the contrast to the incremental sheet forming process, ISR allows the manufacture of long and open sections from HSS sheets. In this work, the experimental prototyping trials of the ISR process are performed using a 5-axis milling machine and then are used to validate the FEA model which is developed to simulate and analyse the deformation behaviour of the ISR process. The results show a clear development of transverse tensile strain along the flange which can overcome the wrinkling issue when the ISR process is applied to complex profiles.
Evaluation of testing methods for the characterization of material properties under plane strain
Authors: Lenzen M , Merklein M
Published: May 2022

With the first numerically calculated forming simulations of a complex component by Hora in 1987, a renewed need emerged for a large number of stress-based material parameters for the yield locus modelling. Material characterization and modelling under plane strain is an important step towards an improved mapping accuracy in numerical calculated sheet metal forming processes. There are numerous of different testing methods, which can be used for this purpose. It is crucial to choose the right experiment depending on which material properties or characteristic values are needed. The aim of this investigation is to analyze the suitability of the currently mostly used testing methods that induce a plane strain in the material, the notched tensile test, the biaxial tensile test and the hydraulic bulge test with an elliptical die. For this purpose, the stress-based material properties of DC06 in all three tests are determined and compared. Subsequently, recommendations for material characterization are derived depending on the application.
Comparative study of certain substituted ions in hydroxyapatite: characterization and effect on cell viability
Authors: Korowash Sara Ibrahim , Abo-Almaged Hanan Hassan , Ibrahim Doreya M.
Published: May 2022

Hydroxyapatite (HA) is a biomaterial that has been widely studied for uses such as bone grafting and tissue engineering. Pure and hydroxyapatite nanoparticles with cationic (Na, Ti, and Li) as well as anionic (

CO

3

2
−

and Si4+) substitutions were synthesised using a wet chemical precipitation method followed by freeze-drying and investigated for their cytotoxicity effect. Inductively coupled plasma (ICP), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy were used to characterise the produced powders. The production of the HA phase was confirmed in all synthesised HA samples. MTT (3-(4.5-dimethylthiazol-2-yl)−2.5-diphenyl tetrazolium bromide) assay was performed using the BJ1 cell line of human normal fibroblasts to investigate the cytotoxicity of the synthesised HA samples. The cytotoxicity test showed that the HA samples were biocompatible, with the greatest results coming from Li-substituted (LiHA2) and Na-substituted (NaHA) hydroxyapatite.
Microscopic investigation on blending of montmorillonite modified bitumen and reclaimed asphalt binder
Authors: Dai Min , Chen Chang-ming , Wang Zhan , Pan Wen-hao , Sun Xiao-wei , Tang Ning , Wu Li-mei
Published: May 2022

The performance of asphalt mixtures containing reclaimed asphalt pavement (RAP) are strongly influenced by the degree of blending between RAP and virgin bitumen. In the aim of revealing the blending interface, the present work reports an experimental investigation on the blending degree between modified bitumen and RAP (or aged bitumen). A montmorillonite-rhodamine composite modifier was prepared as a tracer, which has exclusive element and fluorescence. Using microscopic test technique, the blending process of and the crack process of RAP bitumen was observed, and the blending image of new reclaimed asphalt mixture was obtained. The interface was investigated through image processing and machine learning. Based on the results, the montmorillonite modifier slightly affected on the softening point and penetration of virgin bitumen after addition. The blending interface was engagement like gears. The optimal heating temperature range is 110 °C to 115 °C for forming a better adhesive interface between RAP and modified bitumen. Moreover, the interface transition zone thickness between RAP and modified bitumen was measured to be 4 to 8 μm.
Efficient Bayesian phase estimation via entropy-based sampling
Authors: Qiu Yuxiang , Zhuang Min , Huang Jiahao , Lee Chaohong
Published: May 2022

Bayesian estimation approaches, which are capable of combining the information of experimental data from different likelihood functions to achieve high precisions, have been widely used in phase estimation via introducing a controllable auxiliary phase. Here, we present a Bayesian phase estimation (BPE) algorithm with an ingenious update rule of the auxiliary phase designed via entropy-based sampling. Unlike other adaptive BPE algorithms, the auxiliary phase in our algorithm is determined only once in a pre-estimation step. With simple statistical analysis on a small batch of data, an iteration rule for the auxiliary phase is pre-established and used in all afterward updates, instead of complex calculations in every update trails. During this pre-estimation process the most informative data can be selected, which guides one to perform the BPE with much less measurement times. As the measurement times for the same amount of Bayesian updates is significantly reduced, our algorithm via entropy-based sampling can work as efficient as other adaptive BPE algorithms and shares the advantages (such as wide dynamic range and perfect noise robustness) of non-adaptive BPE algorithms. Our algorithm is of promising applications in various practical quantum sensors such as atomic clocks and quantum magnetometers.
On orthogonal bases in the Hilbert-Schmidt space of matrices
Authors: Siewert Jens
Published: May 2022

Decomposition of (finite-dimensional) operators in terms of orthogonal bases of matrices has been a standard method in quantum physics for decades. In recent years, it has become increasingly popular because of various methodologies applied in quantum information, such as the graph state formalism and the theory of quantum error correcting codes, but also due to the intensified research on the Bloch representation of quantum states. In this contribution we collect various interesting facts and identities that hold for finite-dimensional orthogonal matrix bases.
Citizens with Benefits
Authors: Stemplowska Zofia
Published: May 2022

Can states permissibly enforce mandatory participation in the provision of public goods? Usual justifications of state action here appeal to the fact that such goods are very good for people. Arthur Ripstein argues that states can compel provision of public goods, but that the best explanation of this is grounded, not in the costs and benefits of the provision to the compelled parties, but in the parties’ moral status as independent agents. I argue that Ripstein’s alternative account poses more problems than it solves. Our best hope in grounding mandatory cooperation is to do so with reference to the duties that we have to serve people’s interests, including interests in autonomy, welfare, and being respected on account of one’s moral status.
Cryptocurrency: The Future of Plastic Surgery Payments?
Authors: Atamian Elisa K , Bastidas Nicholas
Published: May 2022

Cryptocurrencies are digital currencies that allow for peer-to-peer transactions, maintained by a decentralized, secure, and trust-based system. Similar to the patient-centered care approach, cryptocurrency empowers the individual to transact, without a third-party, in a safe, largely transparent, and fast way. Awareness of the current economic state and the ongoing growth of cryptocurrency can place plastic surgeons in a unique and opportune position to broaden payment acceptance methods and create a more effective business model. By first creating a digital wallet for storage, and then employing a payment processing tool, transacting with cryptocurrency becomes practical and convenient. This paper explores the advantages and limitations of cryptocurrency and provides a high-level breakdown of the basics of accepting and transacting with cryptocurrency within a successful plastic surgery practice.
Painless, Drainless Lipoabdominoplasty: A Retrospective Study of Pain Following Lipoabdominoplasty Utilizing Liposomal Bupivacaine and a Modified Enhanced Recovery After Surgery Protocol
Authors: Shauly Orr , Goel Pedram , Gould Daniel J
Published: May 2022

Background

There are many functional and aesthetic benefits to lipoabdominoplasty (combination of liposuction with abdominoplasty), including increase in core strength, reduction in urinary incontinence, and improvement in lower back pain. However, patients are still hesitant to undergo surgery due to the perceived fears of postsurgical drains, and postoperative pain.

Objectives

To propose a standardized multimodal pain protocol for patients undergoing lipoabdominoplasty procedures that aims to improve postoperative pain control.

Methods

A total of 80 patients operated on between July 2020 and December 2021 were evaluated in this study. Patients all underwent lipoabdominoplasty and were administered a standardized preoperative, intraoperative, and postoperative pain regimen. Pain scores were measured across all patients in the immediate postoperative period, and postoperative days (PODs) 1, 7, 28, and 90.

Results

Mean pain scores in the postanesthesia recovery unit were 0.46/10 (+/− 0.18). Subsequent reassessment in the postop recovery suite yielded mean pain scores of 0.34 (+/− 0.15). Mean pain scores on POD1 were 1.23 (+/− 0.15) and consistent through to POD7 at 1.24 (+/− 0.11) with patients taking an average of 6.65 total Percocet 5 mg (Endo Pharmaceuticals Inc., Malvern, PA) during the week. After POD7, 95% (76/80) of patients were only taking nonsteroidal anti-inflammatory drugs. A total of 75/80 patients (93.75%) reported zero pain at 4 to 6 weeks after surgery (mean pain score 0.10 +/− 0.08).

Conclusions

The multimodal analgesia protocol consisting of preoperative or immediate induction intravenous Tylenol (Johnson & Johnson, New Brunswick, NJ), precut local analgesia with Marcaine (Pfizer Inc., New York, NY) and lidocaine, and intraoperative use of liposomal bupivacaine can improve perioperative pain control in patients undergoing lipoabdominoplasty.

Level of Evidence: 4
COT: an efficient and accurate method for detecting marker genes among many subtypes
Authors: Lu Yingzhou , Wu Chiung-Ting , Parker Sarah J , Cheng Zuolin , Saylor Georgia , Van Eyk Jennifer E , Yu Guoqiang , Clarke Robert , Herrington David M , Wang Yue
Published: May 2022

Motivation

Ideally, a molecularly distinct subtype would be composed of molecular features that are expressed uniquely in the subtype of interest but in no others—so-called marker genes (MGs). MG plays a critical role in the characterization, classification or deconvolution of tissue or cell subtypes. We and others have recognized that the test statistics used by most methods do not exactly satisfy the MG definition and often identify inaccurate MG.

Results

We report an efficient and accurate data-driven method, formulated as a Cosine-based One-sample Test (COT) in scatter space, to detect MG among many subtypes using subtype expression profiles. Fundamentally different from existing approaches, the test statistic in COT precisely matches the mathematical definition of an ideal MG. We demonstrate the performance and utility of COT on both simulated and real gene expression and proteomics data. The open source Python/R tool will allow biologists to efficiently detect MG and perform a more comprehensive and unbiased molecular characterization of tissue or cell subtypes in many biomedical contexts. Nevertheless, COT complements not replaces existing methods.

Availability and implementation

The Python COT software with a detailed user’s manual and a vignette are freely available at https://github.com/MintaYLu/COT.

Supplementary information

Supplementary data are available at Bioinformatics Advances online.
Deep structure integrative representation of multi-omics data for cancer subtyping
Authors: Yang Bo , Yang Yan , Su Xueping
Published: May 2022

Motivation

Cancer is a heterogeneous group of diseases. Cancer subtyping is a crucial and critical step to diagnosis, prognosis and treatment. Since high-throughput sequencing technologies provide an unprecedented opportunity to rapidly collect multi-omics data for the same individuals, an urgent need in current is how to effectively represent and integrate these multi-omics data to achieve clinically meaningful cancer subtyping.

Results

We propose a novel deep learning model, called Deep Structure Integrative Representation (DSIR), for cancer subtypes dentification by integrating representation and clustering multi-omics data. DSIR simultaneously captures the global structures in sparse subspace and local structures in manifold subspace from multi-omics data and constructs a consensus similarity matrix by utilizing deep neural networks. Extensive tests are performed in 12 different cancers on three levels of omics data from The Cancer Genome Atlas. The results demonstrate that DSIR obtains more significant performances than the state-of-the-art integrative methods.

Availability and implementation

https://github.com/Polytech-bioinf/Deep-structure-integrative-representation.git

Supplementary information

Supplementary data are available at Bioinformatics online.
MAFFIN: metabolomics sample normalization using maximal density fold change with high-quality metabolic features and corrected signal intensities
Authors: Yu Huaxu , Huan Tao
Published: May 2022

Motivation

Post-acquisition sample normalization is a critical step in comparative metabolomics to remove the variation introduced by sample amount or concentration difference. Previously reported approaches are either specific to one sample type or built on strong assumptions on data structure, which are limited to certain levels. This encouraged us to develop MAFFIN, an accurate and robust post-acquisition sample normalization workflow that works universally for metabolomics data collected on mass spectrometry (MS) platforms.

Results

MAFFIN calculates normalization factors using maximal density fold change (MDFC) computed by a kernel density-based approach. Using both simulated data and 20 metabolomics datasets, we showcased that MDFC outperforms four commonly used normalization methods in terms of reducing the intragroup variation among samples. Two essential steps, overlooked in conventional methods, were also examined and incorporated into MAFFIN. (i) MAFFIN uses multiple orthogonal criteria to select high-quality features for normalization factor calculation, which minimizes the bias caused by abiotic features or metabolites with poor quantitative performance. (ii) MAFFIN corrects the MS signal intensities of high-quality features using serial quality control samples, which guarantees the accuracy of fold change calculations. MAFFIN was applied to a human saliva metabolomics study and led to better data separation in principal component analysis and more confirmed significantly altered metabolites.

Availability and implementation

The MAFFIN algorithm was implemented in an R package named MAFFIN. Package installation, user instruction and demo data are available at https://github.com/HuanLab/MAFFIN. Other data in this work are available on request.

Supplementary information

Supplementary data are available at Bioinformatics online.
Formalist, Specialist, Pragmatist or Idealist—Approaches to Boundary Spanning in Personal Social Services
Authors: Grell Pär
Published: May 2022

The social services generally operate in the very centre of welfare systems marked by organisational specialisation. However, a downside to high levels of specialisation is the risk of service fragmentation, which may particularly affect clients with complex needs. In this context, work over organisational boundaries—boundary spanning—is a crucial challenge for staff when performing their duties for the benefit of both organisation and clients. The aim of this article is to describe and analyse approaches to boundary spanning in the daily work of Swedish personal social services staff, paying particular attention to the often overlooked informal dimensions of work. Findings from a non-participation observation study and a group interview study are presented. Four approaches to boundary spanning are identified and conceptualised: the ‘formalist’, ‘specialist’, ‘pragmatist’ and ‘idealist’ approaches. The article concludes with a discussion of influence of these approaches—and particularly dimensions of informal organisation—on future challenges for a specialised welfare sector.
Serum Neutralizing Antibody Titers 12 Months After Coronavirus Disease 2019 Messenger RNA Vaccination: Correlation to Clinical Variables in an Adult, US Population
Authors: Zhao Min , Slotkin Rebecca , Sheth Amar H , Pischel Lauren , Kyriakides Tassos C , Emu Brinda , McNamara Cynthia , Shi Qiaosu , Delgobbo Jaden , Xu Jin , Marhoffer Elizabeth , Mercer-Falkoff Aleagia , Holleck Jürgen , Ardito David , Sutton Richard E , Gupta Shaili
Published: May 2022

Background

We studied whether comorbid conditions affect strength and duration of immune responses after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA vaccination in a US-based, adult population.

Methods

Sera (before and after BNT162b2 vaccination) were tested serially up to 12 months after 2 doses of vaccine for SARS-CoV-2-anti-Spike neutralizing capacity by pseudotyping assay in 124 individuals; neutralizing titers were correlated to clinical variables with multivariate regression. Postbooster (third dose) effect was measured at 1 and 3 months in 72 and 88 subjects, respectively.

Results

After completion of primary vaccine series, neutralizing antibody half maximal inhibitory concentration (IC50) values were high at 1 month (14-fold increase from prevaccination), declined at 6 months (3.3-fold increase), and increased at 1 month postbooster (41.5-fold increase). Three months postbooster, IC50 decreased in coronavirus disease (COVID)-naïve individuals (18-fold increase) and increased in prior COVID 2019 (COVID-19+) individuals (132-fold increase). Age >65 years (β = −0.94, P = .001) and malignancy (β = −0.88, P = .002) reduced strength of response at 1 month. Both neutralization strength and durability at 6 months, respectively, were negatively affected by end-stage renal disease ([β = −1.10, P = .004]; [β = −0.66, P = .014]), diabetes mellitus ([β = −0.57, P = .032]; [β = −0.44, P = .028]), and systemic steroid use ([β = −0.066, P = .032]; [β = −0.55, P = .037]). Postbooster IC50 was robust against WA-1 and B.1.617.2. Postbooster neutralization increased with prior COVID-19 (β = 2.9, P < .0001), and malignancy reduced neutralization response (β = −0.68, P = .03), regardless of infection status.

Conclusions

Multiple clinical factors affect the strength and duration of neutralization response after primary series vaccination, but not the postbooster dose strength. Malignancy was associated with lower booster-dose response regardless of prior COVID infection, suggesting a need for clinically guided vaccine regimens.
Variable Effects of Temperature and Relative Humidity onRhipicephalus sanguineuss.l. (Acari: Ixodidae) Development
Authors: Tian Yuexun , Kaufman Phillip E , Taylor Caitlin E , Beati Lorenza , Lord Cynthia C
Published: May 2022

Rhipicephalus sanguineus s.l. (Latreille, 1806) can establish populations in residences and may lead to severe domestic and peridomestic infestations. Detection in the early infestation stage is challenging because of their small body size and the lack of visibility when ticks stay in sheltered refugia. The residents may believe that the infestation has been eliminated when no ticks are observed until ticks reappear when seeking hosts. Thus, it is necessary to improve our understanding of tick phenology to achieve more effective infestation management. In this study, the relationships between environmental conditions and tick development were explored in laboratory and using linear and nonlinear models. Three R. sanguineus s.l. strains, from one colony of the temperate lineage and two of the tropical lineage, were evaluated for the development of all life stages and conversion efficiency index (CEI) under five temperatures and four relative humidities (RHs). The development times differed between the three tick strains across stages and were primarily dependent on temperature. The CEIs had little variance explained by temperature, RH, or strains. Compared with the linear and exponential models with temperature as the only variable, the Brière-1 model was the best approximating model for most of the developmental rates. The developmental temperature thresholds for R. sanguineus s.l. development estimated by the Brière-1 model varied inconsistently across strains and life stages. We developed a more predictive relationship between environmental factors and R. sanguineus s.l. development, which can be utilized to predict tick development using temperature and develop appropriate control strategies.
Patch enlargement may not be a good strategy for treating tetralogy of Fallot with unbalanced pulmonary artery branches
Authors: Gao Botao , Zhu Zhongqun
Published: May 2022

OBJECTIVES

Our goal was to determine the optimal strategy for managing tetralogy of Fallot (TOF) with unbalanced pulmonary artery (PA) branches by investigating the different effects of PA plasty on the development of hypoplastic PA (HPA).

METHODS

A single-centre, retrospective analysis was carried out to compare the outcome of different PA plasty methods on the development of HPA in patients with TOF with unbalanced PA branches. Size and balance of the PA branches were used to evaluate the outcome of PA plasty.

RESULTS

In the NATIVE group, 100% of the HPAs were well-developed and all PA branches became balanced, whereas in the PATCH and EXTENSION groups, the percentage of well-developed HPAs was 40% and 33%, respectively, and none of the PA branches were balanced. In addition, HPAs became atretic in 28% of the patients in the patch enlargement group.

CONCLUSIONS

For TOF with unbalanced PA branches, patch enlargement may not be a good treatment strategy, because it reduces the growth potential of HPA and even causes iatrogenic atresia. Leaving the HPA in the native state without patch enlargement may be a good strategy.
Transseptal versus left atrial approach for mitral valve surgery: postoperative need for pacemaker
Authors: Ntinopoulos Vasileios , Haeussler Achim , Dushaj Stak , Papadopoulos Nestoras , Fleckenstein Philine , Dzemali Omer
Published: May 2022

OBJECTIVES

Concerns exist about higher rates of pacemaker implantation using the extended superior transseptal approach for mitral valve surgery. This study aims to compare the extended superior transseptal and the left atrial approach regarding the need for pacemaker implantation after mitral valve surgery.

METHODS

We performed a retrospective analysis of the data of patients undergoing mitral valve surgery through either a sternotomy and transseptal approach or a mini-thoracotomy and left atrial approach in a single centre in the period January 2010 to May 2021. The primary outcome was the evaluation of the postoperative pacemaker implantation rate.

RESULTS

Overall, 677 patients were included, 333 with transseptal and 344 with left atrial approach, and 58 (8.6%) patients underwent pacemaker implantation postoperatively. There was no significant difference in the rate of pacemaker implantation between the 2 groups [overall: 34 (10.2%) vs 24 (7%), P = 0.133; for sinus node dysfunction: 12 (3.6%) vs 9 (2.6%), P = 0.459; for high-degree atrioventricular block: 22 (6.6%) vs 15 (4.4%), P = 0.199; transseptal vs left atrial approach, respectively]. A subgroup analysis of the relative effect of transseptal versus left atrial approach on the rate of postoperative pacemaker implantation revealed mitral replacement as a statistically significant confounder (P = 0.019). The exclusion of patients undergoing concomitant cardiac procedures did not lead to a statistically significant difference in the pacemaker implantation rate between the 2 approaches.

CONCLUSIONS

The analysis of the data of these patients shows no significant difference in the rate of permanent pacemaker implantation between the extended superior transseptal and the left atrial approach for mitral valve surgery.
Developing a Harvest Plan by Considering the Effects of Skidding Techniques on Forest Soil Using a Hybrid TOPSIS-Entropy Method
Authors: Özer Genç Çiğdem , Arıcak Burak
Published: May 2022

The aim of this study was to evaluate skidding techniques, which result in minimal damage to the soil, depending on the slope and stand type. Thus, three skidding techniques with tractor for harvesting (suspended skidding [SS], using a skidding cone [SC], and cable-pulling [CP]) were used in six different study sites and the variations in soil properties were examined at three different slopes (0%–20%, 20%–33%, >33%), 2 different stand types (A, B), and 2 different soil depths (0–5 cm, 5–10 cm). Soil bulk density, soil organic matter, soil compaction, organic carbon (C), and total nitrogen (N) were determined. The Entropy and TOPSIS methods were used among the multiple-criteria decision-making methods for six different coniferous stands.

With the combination of the Entropy and TOPSIS methods, we found that slope was an important factor in determining the preferred skidding technique. Suspended skidding was seen as the preferred method of skidding technique in the 0–20% slope group. For the 20%–33% slope group, the usability of the three methods varied depending on stand type and soil depth, whereas the technique using a skidding cone was found to be the preferred skidding technique in the > 33% slope group.
Probiotic Lactobacillus brevis CLB3 prevents azoxymethane/dextran sulfate sodium-induced colon carcinogenesis in mice by reducing amino acid transport and IL-17A levels and repressing the IL-6/AKT/p-STAT3 signaling pathway
Authors: Qian Weiyi , Zhang Yong , Long Yan , Yang Wei , Hu Rui , Li Jinping , Leng Yan , Liu Xinjie , Li Qing X , Wan Xiangyuan , Wei Xun
Published: May 2022

Amino acid intake plays a crucial role in the Warburg effect of cancer. Gut microbes can regulate intestinal amino acid metabolism. However, it is still unknown whether probiotic therapy can protect the host from intestinal tumor invasion by reducing amino acid intake. With in vitro methods, three acid-tolerant strains from fermented pickles were screened out. Using azoxymethane/dextran sulfate sodium-induced colon cancer models, we evaluated the therapeutic effects of Lactobacillus brevis CLB3, Lactobacillus plantarum XLP, and Lactobacillus johnsonii CM on model mice. Their functional mechanisms were further explained through anatomy section, quantitative reverse transcrip­tion polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemical staining analyses as well as database mining and gut culturomics. The Lactobacillus brevis (L. brevis) CLB3 treatment significantly improved the clinical signs and symptoms of colon cancer, alleviated colon damage, and inhibited colon carcinogenesis in mice. In addition, this treatment significantly increased gut cultivable Lactobacillus abundance, inhibited the expression and translation levels of the tumor metabolism-related solute carrier (SLC) amino acid transporter including SLC7A5 and SLC7A11, lowered circulating interleukin-6 (IL-6) and interleukin-17A (IL-17A) levels, and improved the accumulation of tumor-infiltrating lymphocytes and cancer proliferation factors. These findings suggest that L. brevis CLB3 can reduce amino acid transport, inhibit mammalian target of rapamycin (mTOR) signaling and enhance intestinal anti-tumor immune responses, which provides a potential targeting amino acid transporter strategy for preventing colorectal cancer.