bluuebunny/crossref_metadata_2025 huggingface dataset:
Martensite Transformation in Tool Steels under Isostatic Pressure–Implementation of In-Situ Electrical Resistivity Measurements into a Hot Isostatic Press with Rapid Quenching Technology
Authors: Kramer Berenice , Deng Yuanbin , Lentz Jonathan , Broeckmann Christoph , Theisen Werner , Weber Sebastian
Published: April 2022

Powder metallurgical (PM) parts usually benefit from more homogenous and finer microstructures as opposed to conventionally processed material. In particular, hot isostatic pressing (HIP) combined with near-net-shape technologies can produce almost defect free PM tools with complex geometries. Recent advances in the plant technology of smaller HIP units allow the integration of hardening heat treatments in HIP processes. Thus, additional processing steps, transportation, energy consumption and cost are reduced. However, it is known that high pressure influences phase stability and transformation temperatures. Still, knowledge of the martensite start temperature (MS) is crucial for the design of hardening heat treatment. Since the influence of pressure on MS in HIP heat treatment is insufficiently investigated, it is the aim of this study to deploy a measurement method that allows to record MS as a function of pressure, temperature and cooling rate. Taking the hot working tool steel AISI H11 (X37CrMoV5-1, 1.2343) as the reference material, in this study for the first time the method of an in-situ electrical resistivity measurement was used to measure MS within a HIP. To investigate the influence of HIP pressure on Ms, resulting microstructures and hardness, specimens were austenitized at a temperature of TAUS = 1050 °C for tAUS = 30 min at pAUS = 25, 50, 100 or 150 MPa. Additionally, the MS temperature of the same material was determined by quenching dilatometry at ambient pressure for comparison purposes. Characterization of microstructures was conducted by scanning electron microscopy while hardness as an important technological property of tool steels was measured according to the Vickers method. Furthermore, the CALPHAD method was used to compute the thermodynamic influence of pressure on phase stabilities. The experimental results indicate that the method of in-situ resistivity measurement can be used to measure MS during an integrated HIP heat-treatment process. Besides, a stabilizing effect of pressure on the close packed crystal structure of the austenitic fcc phase is clearly detected, resulting in a reducing influence on the MS temperature of AISI H11 by up to 90 K.
Microstructural Impact on Fatigue Crack Growth Behavior of Alloy 718
Authors: Gruber Christian , Raninger Peter , Maierhofer Jürgen , Gänser Hans-Peter , Stanojevic Aleksandar , Hohenwarter Anton , Pippan Reinhard
Published: April 2022

Alloy 718 for forged parts can form a wide range of microstructures through a variety of thermo-mechanical processes, depending on the number of remelting processes, temperature and holding time of homogenization annealing, cogging and the number of forging steps depending on the forming characteristics. In industrial practice, these processing steps are tailored to achieve specific mechanical and microstructural properties in the final product. In the present work, we investigate the dependence of the threshold of stress intensity factor range ΔKth on associated microstructural elements, namely grain size and distribution. For this purpose, a series of tests with different starting microstructures were performed at the falling stress intensity factor range, ΔK, and a load ratio of R = 0.1 to evaluate the different threshold values. Fracture initiation and crack propagation were analyzed afterward using scanning electron microscopy of the resulting fracture surfaces. In order to obtain comparable initial conditions, all specimens were brought to the same strength level by means of a two-stage aging heat treatment. In the future, this knowledge shall be used in the context of simulation-aided product development for estimating local fatigue crack propagation properties of simulated microstructures obtained from forging and heat treatment modeling.
Influence of CDFW Process Parameters on Microstructure and Mechanical Properties of U75V Rail Steel Welded Joint
Authors: Zhang Han , Li Chang’an , Zhu Zhiming
Published: April 2022

In the present paper, the continuous-drive friction welding (CDFW) technology has been successfully applied to join the U75V rail steel. The base metal (BM) of U75V rail steel is lamellar pearlite, and the weld zone could be clearly divided into three subzones (i.e., heat affected zone, thermo-mechanical affected zone (TMAZ), and central weld zone (CWZ)). Electron back-scattered diffraction examinations revealed the martensitic evolution in TMAZ and CWZ, suggesting that the experienced high temperature, severe plastic deformation, and fast cooling rate induce the microstructure transition during the CDFW process. The hard and brittle martensite structure explains the raised microhardness profiles and the reduced impact absorption energy of the as-welded joints. The CDFW process parameters govern the joint properties via influencing the welding heat input and plastic deformation by spindle speed and friction pressure at the friction stage, and the plastic deformation layer (flash) extrusion by upsetting pressure at the upsetting stage. More favorable results could be obtained at small set values of spindle speed (1800 rpm) and friction pressure (75 MPa) with less heat input and plastic deformation, and a large set value of upsetting pressure (175 MPa) with more flash extrusion, whose tensile strength reached 94.3% of that of the BM.
The Response Mechanism of Crystal Orientation to Grain Boundary Dislocation under Uniaxial Strain: A Phase-Field-Crystal Study
Authors: Wang Xiaona , Zhang Haibin , Yan Shinong , Zhang Yongmei , Tian Xiaolin , Peng Dunwei , Zhao Yuhong
Published: April 2022

An exploration of dislocation microstructure evolution with different misorientation angles was performed using phase field crystal method (PFC). The microcosmic evolution process of grain boundaries under external stress, as well as the corresponding energy curve and stress–strain curve, are analyzed. The relationship between the misorientation angle and the dislocations emission frequency is discussed. Three forms of dislocations reaction on the evolution process of 6° and 10° are analyzed in detail, which are respectively type I semi-annihilation, type II semi-annihilationand full-annihilation. Among them, the nature of type I semi-annihilation is a combination of dislocation and a single edge dislocation reaction with a single edge dislocation left. The essence of type II semi-annihilation is a pair of dislocation and the other pair of dislocation reaction leaving two edge dislocations. The essence of full-annihilation is that two pairs of dislocations or single edge dislocations with opposite Burger vectors react with each other and the distortion area disappears. When the misorientation angle is 10°, the dislocation reaction and the dislocation motion ability of the system are stronger than 6°. The peak of the energy curve is related to the number of dislocation proliferations in the evolution process. An emission frequency and average density of dislocations of 10° is greater than 6°. The causes of plastic deformation are revealed to a certain extent by stress–strain curves.
Corrosion Inhibition and Rust Conversion of Catechin on Archaeological Iron of Nanhai I
Authors: Jia Minghao , Hu Pei , Gong Zisang , Sun Jian , Cui Yong , Hu Dongbo , Hu Gang
Published: April 2022

This work took the iron objects from the Nanhai No. 1 shipwreck in the Southern Song Dynasty of China as the sample to test and analyze the application potential of catechin, an environmentally friendly corrosion inhibitor and rust converter. The article used metallographic microscopy to clarify that the structure of the iron artifact was hypereutectic white iron. By means of micro-Raman, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), potentiodynamic polarization and electrochemical impedance spectroscopy, catechin had the ability to react with iron oxyhydroxides such as goethite, akaganeite and lepidocrocite in the rust, forming an amorphous substance with a marked signal about 1380 cm−1 as phenolic-Fe in infrared properties. The new products could make the original rust layer form a laminated dense structure. After the archaeological iron was soaked in 3.0 g/L catechin, the corrosion current density decreased by 37.13% and the corrosion potential shifted positively by 32.67 mV. The anode reaction was more inhibited than the cathode in the polarization curve. The rust resistance in electrochemical impedance increased to 3.75 times and the ion diffusion resistance increased to 6.33 times. The corrosion inhibition efficiency was 21.75% and the rust conversion efficiency was 73.26%. After 36 h of accelerated corrosion, the protection effect of the newly transformed rust layer was still better than that of the original state. Catechin was a mild protection material which showed satisfactory performance for archaeological iron and has a good application prospect.
Polymeric Structure Evolution Behavior Analysis of Aluminosilicate-Based Smelting Slag
Authors: Liu Jihui , Kong Weiguo , Yang Xin , Wang Qi , He Zhijun , Hou Xinmei
Published: April 2022

The physical and chemical properties of the CaO–SiO2–Al2O3–MgO slag system depend on structure evolution caused by the synergistic mechanism among the components at high temperature, especially the structural complexity of the anion group. In this study, Si–O, Al–O, and Al–Si–O anion groups were found in the high-temperature slag systems at 1773 K. The [Si2O5]2− (Q3) structural unit of the silicate polymer changed to [Si2O6]4− (Q2), [Si2O7]6− (Q1), and [SiO4]4− (Q0) as the binary basicity (R2) and ω(MgO)/ω(Al2O3) increased, while there was a trend toward a simplified structure. That is, the stability of each structural unit weakened, and the relative content of non-bridging oxygen increased. As a result, the degree of polymerization of slag decreased, and the experimental results of the relative content of non-bridge oxygen can be fitted well with the calculations from the reference documents. At the same time, the number of Si–O–Al structural units gradually decreased. The 27Al-MAS-NMR spectroscopy results showed that the structure of aluminate changed from [AlO4]5− tetrahedral structure to [AlO5]7− pentahedral and [AlO6]9− octahedral structure, and the degree of polymerization of the slag decreased. Comprehensive analysis showed that basicity controlled within 1.2 with the ω(MgO)/ω(Al2O3) ratio; less than 0.55 allows for suitable fluidity and energy-saving ability, which is beneficial for the stable and smooth production of the blast furnace.
Correlation between Microstructure and Mechanical Properties of Welded Joint of X70 Submarine Pipeline Steel with Heavy Wall Thickness
Authors: Dong Yifan , Liu Denghui , Hong Liang , Liu Jingjing , Zuo Xiurong
Published: April 2022

This paper aims to study the relationship between the microstructure and the mechanical properties of X70 submarine pipeline steel with 40.5 mm thickness. The microstructure was examined by using optical microscopy, scanning electron microscopy and an electron backscattered diffractometer, while the mechanical properties were examined by using a hardness test, a tensile test, a Charpy impact test and a drop weight tear test (DWTT), respectively. The results show that the base metal (BM) of the pipe has a low yield ratio of 0.83 and an excellent elongation of more than 45%. The DWTT shear area of the steel plate reaches 87%, showing excellent low-temperature toughness. The Charpy impact energy increases when the distance from the fusion line increases, and it reaches a maximum at the BM near the heat-affected zone (HAZ) due to the small martensite-austenite (MA) constituents and fine grains. The concentrated distribution of blocky/slender MA constituents along the prior austenite grain boundaries of the intercritically reheated coarse-grained HAZ and the large MA constituents are the main reasons for the deteriorating impact toughness. Delamination cracks in the DWTT fracture surface only occurred in the midthickness of a sample with a small opening width that spread about 2.1 mm perpendicular to the DWTT fracture surface and were finally arrested at the acicular ferrite clusters containing a high density of high-angle boundaries.
Evolution of Non-Metallic Inclusions in 27SiMn Steel
Authors: Lu Xinliang , Zhang Zhaohui , Lv Ming , Li Xintao , Song Baomin , Fang Ming
Published: April 2022

To study the evolution of non-metallic inclusions in 27SiMn steel, the 27SiMn steel produced using the LD-LF-CCM process was sampled in various stages in a steel factory. The evolutionary behavior of inclusion in various processes was systematically analyzed by scanning electron microscopy (SEM-EDS), and the total oxygen content and nitrogen content in 27SiMn steel were measured at various production steps. On the basis of the calcium treatment for 27SiMn steel, the equilibrium reactions for Ca-Al were calculated according to the thermodynamic equilibrium model. The results showed that the types of inclusions at the start of LF stations are mainly Al2O3-FeO and MnS-Al2O3. Before calcium treatment, the inclusions are mostly calcium aluminate and CaO-MgO-Al2O3. Compared with the process after soft blowing, the number density of inclusions in tundish increased by 77.88%, possibly due to secondary oxidation. From the soft blowing process to the continuous casting round billet, the inclusions translate into spherical CaO-MgO-Al2O3-SiO2, and a large number of CaS were observed. One part of the CaS precipitated separately, the other part was semi-wrapped with the composite inclusions. At the same time, calcium treatment increases the number density, mean diameter, and the area fraction of inclusions. The mass fraction of T.O. (total oxygen content) increased significantly after soft blowing, and the N content increased greatly from station to tundish. The change trend of N content in steel was basically consistent with that of T.O. content. It was necessary to prevent the secondary oxidation of molten steel during calcium treatment and the casting process. When the liquidus temperature of liquid steel is 1873 K, w[Al] = 0.022%, and w[Ca] in steel is controlled between 1.085 × 10−6 and 4.986 × 10−6, the Al2O3 inclusion degeneration effect is good.
Surface Microstructure and Performance of Anodized TZ30 Alloy in SBF Solution
Authors: Liu Kaiyang , Zhou Yixin , Yin Lixia , Shi Yindong , Huang Guangwei , Liu Xiaoyan , Zheng Liyun , Xing Zhenguo , Zhang Xiliang , Liang Shunxing
Published: April 2022

Anodization is performed on the Ti-30Zr-5Al-3V (TZ30) alloy to improve its surface performance. X-ray diffractometer (XRD), scanning electron microscopy (SEM), and Olympus microscope are used to determine the phase constitution, morphology, and thickness of the anodization film (AOF). Tribological tests and electrochemical corrosion experiments are carried out to measure, respectively, the wear behavior and corrosion resistance of AOFs in simulated body fluid (SBF) solution. The microstructure characteristic of the AOF anodized at low voltage (20 V) is composed of compact and loose regions. As the applied voltage increases to 60 V, the compact regions transform progressively into loose regions, and then grow into nanotube regions. Besides, an increase in thickness of the AOF from 8.6 ± 4.61 μm to 20.7 ± 2.18 μm, and a gradual increase in surface microhardness from 364.6 ± 14.4 HV to 818.4 ± 19.3 HV, are also exhibited as the applied voltage increases from 20 V to 60 V. Specimens anodized at 40 V and 60 V have a low friction coefficient (~0.15) and wear rate (~2.2 mg/N/m) in the SBF solution. The enhanced wearability originates from the high hardness and various wear mechanisms. Potentiodynamic polarization curves suggest that the corrosion resistance in the SBF solution of all anodized specimens is greatly improved, thanks to the protection from the anodized TiO2 film.
Material and Damage Characterization of the Elastoplastic Response of the EK4 Deep Drawing Steel
Authors: Barrera Carlos , García-Herrera Claudio , Celentano Diego J. , Signorelli Javier W.
Published: April 2022

Although EK4 drawing steel is nowadays widely used to manufacture a great variety of parts, it exhibits a marked normal and planar anisotropy that can make it difficult to control the process during its forming. In order to achieve an accurate description of the elastoplastic material response in sheet forming operations, this work presents a detailed material and damage characterization of EK4 deep drawing steel through a two-step methodology involving both experiments and finite element simulations. Firstly, tensile tests on sheet samples cut along the rolling, diagonal and transverse directions were carried out. The corresponding measurements were used to calibrate the material parameters related to the following modeling approaches adopted in the present study: the Hollomon hardening law, the non-associated Hill-48 phenomenological constitutive model and the anisotropic Hosford-Coulomb ductile fracture criterion. Secondly, this characterization was assessed and validated in the numerical simulation of the technological Erichsen test in which the material is mainly subjected to a biaxial stress state. The obtained predictions show a good agreement when compared with the corresponding experimental measurements of the punch load–displacement curve and thickness radial profile at the final fracture stage of the sample.
Patient Stratification in Sepsis: Using Metabolomics to Detect Clinical Phenotypes, Sub-Phenotypes and Therapeutic Response
Authors: Hussain Humma , Vutipongsatorn Kritchai , Jiménez Beatriz , Antcliffe David B.
Published: April 2022

Infections are common and need minimal treatment; however, occasionally, due to inappropriate immune response, they can develop into a life-threatening condition known as sepsis. Sepsis is a global concern with high morbidity and mortality. There has been little advancement in the treatment of sepsis, outside of antibiotics and supportive measures. Some of the difficulty in identifying novel therapies is the heterogeneity of the condition. Metabolic phenotyping has great potential for gaining understanding of this heterogeneity and how the metabolic fingerprints of patients with sepsis differ based on survival, organ dysfunction, disease severity, type of infection, treatment or causative organism. Moreover, metabolomics offers potential for patient stratification as metabolic profiles obtained from analytical platforms can reflect human individuality and phenotypic variation. This article reviews the most relevant metabolomic studies in sepsis and aims to provide an overview of the metabolic derangements in sepsis and how metabolic phenotyping has been used to identify sub-groups of patients with this condition. Finally, we consider the new avenues that metabolomics could open, exploring novel phenotypes and untangling the heterogeneity of sepsis, by looking at advances made in the field with other -omics technologies.
Untargeted Metabolomic Assay of Prefrail Older Adults after Nutritional Intervention
Authors: Jaroch Alina , Kozakiewicz Mariusz , Jaroch Karol , Główczewska-Siedlecka Emilia , Bojko Barbara , Kędziora-Kornatowska Kornelia
Published: April 2022

Frailty is a geriatric syndrome causing a reduction in the body’s functional reserves. Proper nutrition may be helpful in delaying transitioning older adults from pre-frail to frailty syndrome. The present study evaluates the nutritional status of pre-frail patients who underwent nutritional intervention and metabolomic changes resulting from this intervention. Sixteen pre-frail patients (68.4 ± 5.5 years old; 81.3% women) were enrolled for nutritional intervention, and twenty-nine robust elderly people (69.3 ± 5.3 years old; 82.8% women) were the control group. Pre-frail patients consumed 1.0 g protein/kg BW/day for eight weeks through diet modification and an additional daily intake of a protein powder formula. Taken measurements included: Nutritional anthropometry, assessment of food intake, and blood serum analysis with an untargeted metabolomic assessment. Protein consumption increased by 25.8%; moreover, significant increases in body weight (+1.2 kg; p = 0.023) and muscle mass index (+0.1 kg/m2; p = 0.042) were also observed. The untargeted metabolomic assay showed a significant increase in arachidonic acid (p = 0.038), and valine (p = 0.008) among pre-frail patients. Increased protein consumption is reflected in improved anthropometric and biochemical parameters of pre-frail patients. Moreover, metabolomic assay can be a useful tool in determining compliance with dietary recommendations.
Untargeted Metabolomics Profiling of Arabidopsis WT, lbr-2-2 and bak1-4 Mutants Following Treatment with Two LPS Chemotypes
Authors: Offor Benedict C. , Mhlongo Msizi I. , Steenkamp Paul A. , Dubery Ian A. , Piater Lizelle A.
Published: April 2022

Plants perceive pathogenic threats from the environment that have evaded preformed barriers through pattern recognition receptors (PRRs) that recognise microbe-associated molecular patterns (MAMPs). The perception of and triggered defence to lipopolysaccharides (LPSs) as a MAMP is well-studied in mammals, but little is known in plants, including the PRR(s). Understanding LPS-induced secondary metabolites and perturbed metabolic pathways in Arabidopsis will be key to generating disease-resistant plants and improving global plant crop yield. Recently, Arabidopsis LPS-binding protein (LBP) and bactericidal/permeability-increasing protein (BPI)-related proteins (LBP/BPI related-1) and (LBP/BPI related-2) were shown to perceive LPS from Pseudomonas aeruginosa and trigger defence responses. In turn, brassinosteroid insensitive 1 (BRI1)-associated receptor kinase 1 (BAK1) is a well-established co-receptor for several defence-related PRRs in plants. Due to the lack of knowledge pertaining to LPS perception in plants and given the involvement of the afore-mentioned proteins in MAMPs recognition, in this study, Arabidopsis wild type (WT) and mutant (lbr2-2 and bak1-4) plants were pressure-infiltrated with LPSs purified from Pseudomonas syringae pv. tomato DC3000 (Pst) and Xanthomonas campestris pv. campestris 8004 (Xcc). Metabolites were extracted from the leaves at four time points over a 24 h period and analysed by UHPLC-MS, generating distinct metabolite profiles. Data analysed using unsupervised and supervised multivariate data analysis (MVDA) tools generated results that reflected time- and treatment-related variations after both LPS chemotypes treatments. Forty-five significant metabolites were putatively annotated and belong to the following groups: glucosinolates, hydroxycinnamic acid derivatives, flavonoids, lignans, lipids, oxylipins, arabidopsides and phytohormones, while metabolic pathway analysis (MetPA) showed enrichment of flavone and flavanol biosynthesis, phenylpropanoid biosynthesis, alpha-linolenic acid metabolism and glucosinolate biosynthesis. Distinct metabolite accumulations depended on the LPS chemotype and the genetic background of the lbr2-2 and bak1-4 mutants. This study highlights the role of LPSs in the reprogramming Arabidopsis metabolism into a defensive state, and the possible role of LBR and BAK1 proteins in LPSs perception and thus plant defence against pathogenic bacteria.
Evaluating Cefoperazone-Induced Gut Metabolic Functional Changes in MR1-Deficient Mice
Authors: Sun Jinchun , Cao Zhijun , Smith Ashley D. , Carlson Jr Paul E. , Coryell Michael , Chen Huizhong , Beger Richard D.
Published: April 2022

Mucosal-associated invariant T cells are activated following the recognition of bacterial antigens presented by the major histocompatibility complex class I-related molecule (MR1). Previous metagenomics data showed that MR1−/− knock-out (KO) mice had distinct microbiota and displayed a resistance to Clostridioides difficile (CDI) colonization vs. wild-type (WT) mice. In the present study, LC/MS-based untargeted metabolomics are applied to evaluate the changes in metabolic activities, in accordance with the changes in gut microbiota caused by cefoperazone (Cef) treatment. Adult C57Bl/6J WT and MR1−/− KO mice were given sterile drinking water or spiked with 0.5 mg/mL Cef ad libitum for five days. Fecal pellets were collected daily, and both small intestinal and cecal contents were harvested at sacrifice. The PLS-DA score plots of the metabolomic data indicate that the microbiota is relatively less disturbed by Cef treatment in KO mice, which is consistent with the metagenomics data. The most noticeable differences in the metabolome of KO and WT mice were the increases in carbohydrates in the WT mice, but not in the KO mice. Metabolic functional biomarkers were identified through the correlation analysis of gamma-aminobutyric acid (GABA) and riboflavin. These detected metabolic functional biomarkers could provide information complementary to metagenomics data.
Segmental Bronchial Allergen Challenge Elicits Distinct Metabolic Phenotypes in Allergic Asthma
Authors: Zhu Yanlong , Esnault Stephane , Ge Ying , Jarjour Nizar N. , Brasier Allan R.
Published: April 2022

Asthma is a complex syndrome associated with episodic decompensations provoked by aeroallergen exposures. The underlying pathophysiological states driving exacerbations are latent in the resting state and do not adequately inform biomarker-driven therapy. A better understanding of the pathophysiological pathways driving allergic exacerbations is needed. We hypothesized that disease-associated pathways could be identified in humans by unbiased metabolomics of bronchoalveolar fluid (BALF) during the peak inflammatory response provoked by a bronchial allergen challenge. We analyzed BALF metabolites in samples from 12 volunteers who underwent segmental bronchial antigen provocation (SBP-Ag). Metabolites were quantified using liquid chromatography-tandem mass spectrometry (LC–MS/MS) followed by pathway analysis and correlation with airway inflammation. SBP-Ag induced statistically significant changes in 549 features that mapped to 72 uniquely identified metabolites. From these features, two distinct inducible metabolic phenotypes were identified by the principal component analysis, partitioning around medoids (PAM) and k-means clustering. Ten index metabolites were identified that informed the presence of asthma-relevant pathways, including unsaturated fatty acid production/metabolism, mitochondrial beta oxidation of unsaturated fatty acid, and bile acid metabolism. Pathways were validated using proteomics in eosinophils. A segmental bronchial allergen challenge induces distinct metabolic responses in humans, providing insight into pathogenic and protective endotypes in allergic asthma.
Review on Multispectral Photoacoustic Analysis of Cancer: Thyroid and Breast
Authors: Han Seongyi , Lee Haeni , Kim Chulhong , Kim Jeesu
Published: April 2022

In recent decades, photoacoustic imaging has been used widely in biomedical research, providing molecular and functional information from biological tissues in vivo. In addition to being used for research in small animals, photoacoustic imaging has also been utilized for in vivo human studies, achieving a multispectral photoacoustic response in deep tissue. There have been several clinical trials for screening cancer patients by analyzing multispectral responses, which in turn provide metabolomic information about the underlying biological tissues. This review summarizes the methods and results of clinical photoacoustic trials available in the literature to date to classify cancerous tissues, specifically of the thyroid and breast. From the review, we can conclude that a great potential exists for photoacoustic imaging to be used as a complementary modality to improve diagnostic accuracy for suspicious tumors, thus significantly benefitting patients’ healthcare.
Maternal and Fetal Metabolites in Gestational Diabetes Mellitus: A Narrative Review
Authors: Vladu Ionela Mihaela , Clenciu Diana , Mitrea Adina , Amzolini Anca , Micu Simona Elena , Crisan Anda Elena , Efrem Ion Cristian , Fortofoiu Maria , Fortofoiu Mircea Catalin , Mita Adrian , Barau Alhija Anca , Glodeanu Adina Dorina , Mota Maria
Published: April 2022

Gestational diabetes mellitus (GDM) is a major public health issue of our century due to its increasing prevalence, affecting 5% to 20% of all pregnancies. The pathogenesis of GDM has not been completely elucidated to date. Increasing evidence suggests the association of environmental factors with genetic and epigenetic factors in the development of GDM. So far, several metabolomics studies have investigated metabolic disruptions associated with GDM. The aim of this review is to highlight the usefulness of maternal metabolites as diagnosis markers of GDM as well as the importance of both maternal and fetal metabolites as prognosis biomarkers for GDM and GDM’s transition to type 2 diabetes mellitus T2DM.
Specific Changes in Arabidopsis thaliana Rosette Lipids during Freezing Can Be Associated with Freezing Tolerance
Authors: Vu Hieu Sy , Shiva Sunitha , Samarakoon Thilani , Li Maoyin , Sarowar Sujon , Roth Mary R. , Tamura Pamela , Honey Samuel , Lowe Kaleb , Porras Hollie , Prakash Neema , Roach Charles A. , Stuke Morgan , Wang Xuemin , Shah Jyoti , Gadbury Gary , Wang Haiyan , Welti Ruth
Published: April 2022

While the roles of a few specific lipids in plant freezing tolerance are understood, the effect of many plant lipids remains to be determined. Acclimation of plants to non-freezing cold before exposure to freezing temperatures improves the outcome of plants, compared to plants exposed to freezing without acclimation. Arabidopsis thaliana plants were subjected to one of three treatments: (1) “control”, i.e., growth at 21 °C, (2) “non-acclimated”, i.e., 3 days at 21 °C, 2 h at −8 °C, and 24 h recovery at 21 °C, and (3) “acclimated”, i.e., 3 days at 4 °C, 2 h at −8 °C, and 24 h recovery at 21 °C. Plants were harvested at seven time points during the treatments, and lipid levels were measured by direct-infusion electrospray ionization tandem mass spectrometry. Ion leakage was measured at the same time points. To examine the function of lipid species in relation to freezing tolerance, the lipid levels in plants immediately following the freezing treatment were correlated with the outcome, i.e., ion leakage 24-h post-freezing. Based on the correlations, hypotheses about the functions of specific lipids were generated. Additionally, analysis of the lipid levels in plants with mutations in genes encoding patatin-like phospholipases, lipoxygenases, and 12-oxophytodienoic acid reductase 3 (opr3), under the same treatments as the wild-type plants, identified only the opr3-2 mutant as having major lipid compositional differences compared to wild-type plants.
In Vivo Renal Lipid Quantification by Accelerated Magnetic Resonance Spectroscopic Imaging at 3T: Feasibility and Reliability Study
Authors: Alhulail Ahmad A. , Servati Mahsa , Ooms Nathan , Akin Oguz , Dincer Alp , Thomas M. Albert , Dydak Ulrike , Emir Uzay E.
Published: April 2022

A reliable and practical renal-lipid quantification and imaging method is needed. Here, the feasibility of an accelerated MRSI method to map renal fat fractions (FF) at 3T and its repeatability were investigated. A 2D density-weighted concentric-ring-trajectory MRSI was used for accelerating the acquisition of 48 × 48 voxels (each of 0.25 mL spatial resolution) without respiratory navigation implementations. The data were collected over 512 complex-FID timepoints with a 1250 Hz spectral bandwidth. The MRSI sequence was designed with a metabolite-cycling technique for lipid–water separation. The in vivo repeatability performance of the sequence was assessed by conducting a test–reposition–retest study within healthy subjects. The coefficient of variation (CV) in the estimated FF from the test–retest measurements showed a high degree of repeatability of MRSI-FF (CV = 4.3 ± 2.5%). Additionally, the matching level of the spectral signature within the same anatomical region was also investigated, and their intrasubject repeatability was also high, with a small standard deviation (8.1 ± 6.4%). The MRSI acquisition duration was ~3 min only. The proposed MRSI technique can be a reliable technique to quantify and map renal metabolites within a clinically acceptable scan time at 3T that supports the future application of this technique for the non-invasive characterization of heterogeneous renal diseases and tumors.
A Review on Macroscopic and Microstructural Features of Metallic Coating Created by Pulsed Laser Material Deposition
Authors: Wang Xinlin , Jiang Jinkun , Tian Yongchang
Published: April 2022

Owing to the unparalleled advantages in repairing of high value-add component with big size, fabricating of functionally graded material, and cladding to enhance the surface properties of parts, the laser material deposition (LMD) is widely used. Compared to the continuous wave (CW) laser, the controllability of the laser energy would be improved and the temperature history would be different under the condition of pulse wave (PW) laser through changing the pulse parameters, such as duty cycle and pulse frequency. In this paper, the research status of temperature field simulation, surface quality, microstructural features, including microstructures, microhardness, residual stress, and cracking, as well as corrosion behavior of metallic coating created by pulsed laser material deposition have been reviewed. Furthermore, the existing knowledge and technology gaps are identified while the future research directions are also discussed.
Monolayer MoS2-Based Flexible and Highly Sensitive Pressure Sensor with Wide Sensing Range
Authors: Xu Dandan , Duan Ling , Yan Suyun , Wang Yong , Cao Ke , Wang Weidong , Xu Hongcheng , Wang Yuejiao , Hu Liangwei , Gao Libo
Published: April 2022

Flexible pressure sensors play an important role in flexible robotics, human-machine interaction (HMI), and human physiological information. However, most of the reported flexible pressure sensors suffer from a highly nonlinear response and a significant decrease in sensitivity at high pressures. Herein, we propose a flexible novel iontronic pressure sensor based on monolayer molybdenum disulfide (MoS2). Based on the unique structure and the excellent mechanical properties as well as the large intercalation capacitance of MoS2, the prepared sensor holds an ultra-high sensitivity (Smax = 89.75 kPa−1) and a wide sensing range (722.2 kPa). Further, the response time and relaxation time of the flexible sensor are only 3 ms, respectively, indicating that the device can respond to external pressure rapidly. In addition, it shows long-term cycling stability (over 5000 cycles with almost no degradation) at a high pressure of 138.9 kPa. Finally, it is demonstrated that the sensor can be used in physiological information monitoring and flexible robotics. It is anticipated that our prepared sensor provide a reliable approach to advance the theory and practicality of the flexible sensor electronics.
Deterministic Lateral Displacement (DLD) Analysis Tool Utilizing Machine Learning towards High-Throughput Separation
Authors: Gioe Eric , Uddin Mohammed , Kim Jong-Hoon , Chen Xiaolin
Published: April 2022

Deterministic lateral displacement (DLD) is a microfluidic method for the continuous separation of particles based on their size. There is growing interest in using DLD for harvesting circulating tumor cells from blood for further assays due to its low cost and robustness. While DLD is a powerful tool and development of high-throughput DLD separation devices holds great promise in cancer diagnostics and therapeutics, much of the experimental data analysis in DLD research still relies on error-prone and time-consuming manual processes. There is a strong need to automate data analysis in microfluidic devices to reduce human errors and the manual processing time. In this work, a reliable particle detection method is developed as the basis for the DLD separation analysis. Python and its available packages are used for machine vision techniques, along with existing identification methods and machine learning models. Three machine learning techniques are implemented and compared in the determination of the DLD separation mode. The program provides a significant reduction in video analysis time in DLD separation, achieving an overall particle detection accuracy of 97.86% with an average computation time of 25.274 s.
FPGA Implementation of AI-Based Inverter IGBT Open Circuit Fault Diagnosis of Induction Motor Drives
Authors: Rajeswaran Nagalingam , Thangaraj Rajesh , Mihet-Popa Lucian , Krishna Vajjala Kesava Vamsi , Özer Özen
Published: April 2022

In modern industrial manufacturing processes, induction motors are broadly utilized as industrial drives. Online condition monitoring and diagnosis of faults that occur inside and/or outside of the Induction Motor Drive (IMD) system make the motor highly reliable, helping to avoid unscheduled downtimes, which cause more revenue loss and disruption of production. This can be achieved only when the irregularities produced because of the faults are sensed at the moment they occur and diagnosed quickly so that suitable actions to protect the equipment can be taken. This requires intelligent control with a high-performance scheme. Hence, a Field Programmable Gate Array (FPGA) based on neuro-genetic implementation with a Back Propagation Neural network (BPN) is suggested in this article to diagnose the fault more efficiently and almost instantly. It is reported that the classification of the neural network will provide the output within 2 µs although the clone procedure with microcontroller requires 7 ms. This intelligent control with a high-performance technique is applied to the IMD fed by a Voltage Source Inverter (VSI) to diagnose the fault. The proposed approach was simulated and experimentally validated.
An Ultra-Micro-Volume Adhesive Transfer Method and Its Application in fL–pL-Level Adhesive Distribution
Authors: Liu Huifang , Chen Xi , Wang Shuqing , Jiang Shenhui , Chen Ying , Li Fuxuan
Published: April 2022

This study is aimed at addressing the urgent demand for ultra-micro-precision dispensing technology in high-performance micro- and nanometer encapsulation, connection, and assembly manufacturing, considering the great influence of colloid viscosity and surface tension on the dispensing process in micro- and nanometer scale. According to the principle of liquid transfer, a method of adhesive transfer that can realize fL–pL levels is studied in this paper. A mathematical model describing the initial droplet volume and the transfer droplet volume was established, and the factors affecting the transfer process of adhesive were analyzed by the model. The theoretical model of the transfer droplet volume was verified by a 3D scanning method. The relationships between the transfer droplet volume and the initial droplet volume, stay time, initial distance, and stretching speed were systematically analyzed by a single-factor experiment, and the adhesive transfer rate was calculated. Combined with trajectory planning, continuous automatic dispensing experiments with different patterns were developed, and the problems of the transfer droplet size, appearance quality, and position accuracy were analyzed comprehensively. The results show that the average relative deviation of the transfer droplet lattice position obtained by the dispensing method in this paper was 6.2%. The minimum radius of the transfer droplet was 11.7 μm, and the minimum volume of the transfer droplet was 573.3 fL. Furthermore, microporous encapsulation was realized using the method of ultra-micro-dispensing.
Cyclic Electron Flow-Coupled Proton Pumping in Synechocystis sp. PCC6803 Is Dependent upon NADPH Oxidation by the Soluble Isoform of Ferredoxin:NADP-Oxidoreductase
Authors: Miller Neil T. , Ajlani Ghada , Burnap Robert L.
Published: April 2022

Ferredoxin:NADP-oxidoreductase (FNR) catalyzes the reversible exchange of electrons between ferredoxin (Fd) and NADP(H). Reduction of NADP+ by Fd via FNR is essential in the terminal steps of photosynthetic electron transfer, as light-activated electron flow produces NADPH for CO2 assimilation. FNR also catalyzes the reverse reaction in photosynthetic organisms, transferring electrons from NADPH to Fd, which is important in cyanobacteria for respiration and cyclic electron flow (CEF). The cyanobacterium Synechocystis sp. PCC6803 possesses two isoforms of FNR, a large form attached to the phycobilisome (FNRL) and a small form that is soluble (FNRS). While both isoforms are capable of NADPH oxidation or NADP+ reduction, FNRL is most abundant during typical growth conditions, whereas FNRS accumulates under stressful conditions that require enhanced CEF. Because CEF-driven proton pumping in the light–dark transition is due to NDH-1 complex activity and they are powered by reduced Fd, CEF-driven proton pumping and the redox state of the PQ and NADP(H) pools were investigated in mutants possessing either FNRL or FNRS. We found that the FNRS isoform facilitates proton pumping in the dark–light transition, contributing more to CEF than FNRL. FNRL is capable of providing reducing power for CEF-driven proton pumping, but only after an adaptation period to illumination. The results support that FNRS is indeed associated with increased cyclic electron flow and proton pumping, which is consistent with the idea that stress conditions create a higher demand for ATP relative to NADPH.
The Meta-Substituted Isomer of TMPyP Enables More Effective Photodynamic Bacterial Inactivation than Para-TMPyP In Vitro
Authors: Schulz Sebastian , Ziganshyna Svitlana , Lippmann Norman , Glass Sarah , Eulenburg Volker , Habermann Natalia , Schwarz Ulrich T. , Voigt Alexander , Heilmann Claudia , Rüffer Tobias , Werdehausen Robert
Published: April 2022

Porphyrinoid-based photodynamic inactivation (PDI) provides a promising approach to treating multidrug-resistant infections. However, available agents for PDI still have optimization potential with regard to effectiveness, toxicology, chemical stability, and solubility. The currently available photosensitizer TMPyP is provided with a para substitution pattern (para-TMPyP) of the pyridinium groups and has been demonstrated to be effective for PDI of multidrug-resistant bacteria. To further improve its properties, we synthetized a structural variant of TMPyP with an isomeric substitution pattern in a meta configuration (meta-TMPyP), confirmed the correct structure by crystallographic analysis and performed a characterization with NMR-, UV/Vis-, and IR spectroscopy, photostability, and singlet oxygen generation assay. Meta-TMPyP had a hypochromic shift in absorbance (4 nm) with a 55% higher extinction coefficient and slightly improved photostability (+6.9%) compared to para-TMPyP. Despite these superior molecular properties, singlet oxygen generation was increased by only 5.4%. In contrast, PDI, based on meta-TMPyP, reduced the density of extended spectrum β-lactamase-producing and fluoroquinolone-resistant Escherichia coli by several orders of magnitude, whereby a sterilizing effect was observed after 48 min of illumination, while para-TMPyP was less effective (p < 0.01). These findings demonstrate that structural modification with meta substitution increases antibacterial properties of TMPyP in PDI.
Seasonal and Zonal Succession of Bacterial Communities in North Sea Salt Marsh Sediments
Authors: Tebbe Dennis Alexander , Geihser Simone , Wemheuer Bernd , Daniel Rolf , Schäfer Hendrik , Engelen Bert
Published: April 2022

Benthic microbial communities of intertidal zones perform important biogeochemical processes and provide accessible nutrients for higher organisms. To unravel the ecosystem services of salt marsh microbial communities, we analyzed bacterial diversity and metabolic potential along the land–sea transition zone on seasonal scales on the German North Sea Island of Spiekeroog. Analysis of bacterial community was based on amplicon sequencing of 16S rRNA genes and –transcripts. Insights into potential community function were obtained by applying the gene prediction tool tax4fun2. We found that spatial variation of community composition was greater than seasonal variations. Alphaproteobacteria (15%), Gammaproteobacteria (17%) and Planctomycetes (11%) were the most abundant phyla across all samples. Differences between the DNA-based resident and RNA-based active communities were most pronounced within the Planctomycetes (17% and 5%) and Cyanobacteriia (3% and 12%). Seasonal differences were seen in higher abundance of Gammaproteobacteria in March 2015 (25%) and a cyanobacterial summer bloom, accounting for up to 70% of the active community. Taxonomy-based prediction of function showed increasing potentials for nitrification, assimilatory nitrate and sulfate reduction from sea to land, while the denitrification and dissimilatory sulfate reduction increased towards the sea. In conclusion, seasonal differences mainly occurred by blooming of individual taxa, while the overall community composition strongly corresponded to locations. Shifts in their metabolism could drive the salt marsh’s function, e.g., as a potential nitrogen sink.
Probiotic Characteristics and Antimicrobial Potential of a Native Bacillus subtilis Strain Fa17.2 Rescued from Wild Bromelia sp. Flowers
Authors: Tenea Gabriela N. , Gonzalez Gabriela Lizeth , Moreno Jose Luis
Published: April 2022

In the present study, we identified the Bacillus subtilis strain annotated Fa17.2 isolated from Bromelia flower inflorescences collected from the subtropical humid mesothermal region, Santo Domingo de Los Tsachilas Province, Ecuador. The probiotic capacity and antimicrobial potential against four foodborne pathogens were assessed. The cell culture of Fa17.2 is highly resistant to synthetic gastric acid (pH 2.5, 3.0, and 3.5), bile salts (0.3%), tolerating different sodium chloride concentrations (1, 3, and 5%), and growth conditions (15 °C and 45 °C), suggesting its potential probiotic features. The isolate showed no antibiotic resistance and was considered safe as no hemolysis was detected on sheep blood agar. The optimum medium for bacterial growth and the release of antimicrobial compounds was MRS with 10% glucose. The active components released in the neutralized crude extract (NCE) were insensitive to organic solvents, surfactants, and nonproteolytic enzymes and sensitive to proteolytic enzymes suggesting their proteinaceous nature. The antimicrobial activity was enhanced by heat and maintained active over a wide range of pH (2.0–8.0). Moreover, the crude extract (CE) showed inhibitory activity against several Gram-negative and Gram-positive bacteria. The molecular weight of partially purified precipitated bacteriocin-like substances (BLISs) was about 14 kDa in 20% Tricine-SDS-PAGE. The CE obtained from Fa17.2 inhibits the growth of four foodborne pathogens, Staphylococcus aureus, Escherichia coli, Kosaconia cowanii, and Shigella dysenteriae, which implies its potential as an antimicrobial producer strain.