bluuebunny/crossref_metadata_2025 huggingface dataset:
Pilot Study on Seismic Fragility Evaluation for Degraded Austenitic Stainless Steel Piping Using the Probabilistic Fracture Mechanics Code PASCAL-SP
Authors: Azuma Kisaburo , Yamaguchi Yoshihito , Li Yinsheng
Published: October 2021

Seismic probabilistic risk assessment is a standard methodology to quantify the risk of earthquakes including beyond-design-basis levels. The quality of fragility analysis is one of the major factors that affect the results of seismic probabilistic risk assessments. A previous study revealed that component degradation could affect seismic fragility. In practice, inspection and maintenance programs are implemented to control an undesirable effect of the degradation such as stress corrosion cracking. However, the relation between seismic fragility of degraded component and inspection, maintenance, and mitigation models has not been thoroughly discussed so far. This study discussed the effect of inspection and maintenance on seismic fragility of austenitic stainless steel piping susceptible to stress corrosion cracking. Failure probability was calculated by using a probabilistic fracture mechanics code. The results indicated that the adverse effects of stress corrosion cracking on failure probability could be controlled at a relatively low level if inspection, maintenance, and mitigation measures were implemented properly.
Mechanical Response of an Industrial Piping System Under Strong Cyclic Loading
Authors: Karvelas C. , Chatzopoulou G. , Zervaki A. D. , Stathas N. , Strepelias E. , Palios X. , Bousias S. N. , Karamanos S. A.
Published: October 2021

The paper presents a combined experimental and numerical investigation of cyclic loading response of an internally pressurized steel piping system. The piping system comprises three elbows and is subjected to quasi-static end-displacement excitation. Global deformation and local strain measurements are obtained, indicating significant strain ratcheting at the critical locations of the elbows. The piping system failed under low-cycle fatigue undergoing through-thickness cracking at the flank of the most strained elbow. Post-fatigue metallographic examination of the elbows indicated that fatigue cracking initiates from the inner surface of the pipe elbow. In all elbows, several micro-cracks develop along the inner surface of elbow flanks, whereas the outer surface remained practically intact before through-thickness cracking. Finite element simulations, with a properly calibrated cyclic-plasticity model calibrated properly in terms of small-scale material tests, provide very good predictions in terms of local strain evolution at critical locations.
Investigation of the Irradiation Effect on the Dynamics of Nuclear Fuel Bundles
Authors: Elbanhawy Osama , Hassan Marwan , Mohany Atef , Kishawy Hossam
Published: October 2021

Fuel bundles in nuclear power plants are subjected to severe operation conditions, such as highly turbulent coolant flow, high temperatures and excessive irradiation doses. These irradiation doses affect the microstructure of the material in terms of segregation and precipitation in addition to swelling. For instance, densification occurs when material pores are removed after irradiation. In contrast, swelling occurs when gaseous pores of fission products start to fill materials used in the reactor core components. All these effects influence the mechanical properties of the material and consequentially its dynamic characteristics. The present study aims at developing a fully-coupled three dimensional numerical model that utilizes the irradiated fuel bundle material as a non-linear material rather than a linear one. The non-linearity is accounted for with the aid of a constitutive model that describes the thermal and irradiation effects on the mechanical properties. Then this constitutive model is integrated in an in-house finite element code that is capable of predicting the dynamics of non-linear material. The model is applied to a CANDU fuel bundle, in which each fuel element is discretized using 12-DOF beam elements and the endplates are discretized using plate elements. The dynamic response of the fuel bundle is investigated under turbulence excitation, which is generated by the coolant flow inside the pressure tube. Moreover, the fuel-to-fuel and fuel-to-pressure tube contact is also included using the single point contact method (SPC). The dynamic response of the fuel bundle along with the associated impact forces and work rates are investigated over a range of flow velocities that are typical to those in an actual CANDU power plant. A summary of the results is presented in this paper.
Experimental Characterization of the Ageing Behaviour of Anaerobic Threadlockers
Authors: Croccolo Dario , De Agostinis Massimiliano , Fini Stefano , Olmi Giorgio , Paiardini Luca , Robusto Francesco
Published: October 2021

Threadlockers are widely used in threaded connections in order to prevent the preload loss (e.g., due to self-loosening). Threadlockers are commercially available in different formulations, such as liquid (to be applied just before tightening) or semi-solid (pre-applied on the screw). Previous research focused on both the frictional behaviour at tightening of the joint with applied threadlocker, and on the breakaway torque of the joint after complete polimerization of the threadlocker. Nonetheless, threadlocker-enhanced joints are often operated at variable levels of temperature and humidity. A literature survey reveals lack of data about the residual strength of threadlocker-enhanced joints after operation at temperature/humidity levels different by the reference ambient levels. The present research tackles the aforementioned issue, by means of an experimental campaign carried out on a liquid medium-strength anaerobic adhesive applied to metric, 8.8 grade, Zinc-coated screws. Upon complete polimerization of the adhesive, the joints have been aged in an environmental chamber at four different combinations of temperature (RT – 90°C) and humidity (20%–90%) for one week. The joints have then been unlocked, sampling the breakaway torque. Statistical analysis of the data has been carried out to determine the significance of each parameter on the breakaway torque of the aged joint.
Tribological Analysis of Squeeze Stir Cast Recycled Aluminum MMC’s
Authors: Victor Christy John , Mourad Abdel-Hamid I. , Qudeiri Jaber Abu
Published: October 2021

In this work, squeeze stir casting was used to produce recycled Aluminum Metal Matrix Composites (MMC’s) plates. Scrap Aluminum Alloy Wheel (SAAW) was used as a matrix and alumina as reinforcement. The produced recycled MMC plate was subjected to abrasive and sliding wear using a Two-body abrasion tester and Pin-on-Disc tester with a load of 20 N. To improve the wear resistance of the recycled MMC, graphite (1% to 4%) and SiC (3% and 6%) were added to alumina, and the results were compared. The results showed that the addition of graphite and SiC to alumina decreased the wear rate and frictional forces compared to using alumina alone as reinforcements. Also, wear rates and frictional forces further reduced by increasing the percentage of graphite to 4%, whereas increasing the SiC content increased the wear. Scanning Electron Microscopy (SEM) analysis and microstructure analysis was conducted on these samples. These results confirmed that graphite and alumina exhibited better bonding to the SAAW matrix than SiC. Since this recycled Aluminum MMC achieves a cleaner production process, it has great industrial potential, including applications in the piping industry, and its tribological properties can be boosted using graphite (4% by wt.) with alumina (5% by wt.) as reinforcements.
Further Development of Probabilistic Leak-Before-Break Methods
Authors: Gill Peter , Daniels Brian
Published: October 2021

Leak-before-Break software has been developed to provide probabilities of detecting a leak from a circumferential crack in a pipe. This utilizes the methods detailed in the UK structural integrity assessment procedure, R6, and was presented in PVP2020-21769. The latest developments in this code are presented in this paper and account for initial surface defects that can develop over time to become through wall cracks. This is possible through the implementation of stress intensity factor solutions for semi-elliptical circumferential flaws in cylinders of Chapuliot et. al and crack growth laws due to Stress Corrosion Cracking.

The results presented in this paper demonstrates the functionality of the code with sample problems that are designed to be plant representative. Probability of detection is also accounted for and enables reliabilities to be calculated based on probability of failure from the Monte Carlo simulations.
Equivalent Diameter for Predicting Vortex Shedding of Finned Cylinders in Cross-Flow
Authors: Alziadeh Mohammed , Mohany Atef
Published: October 2021

This article explores different equivalent diameter equations found in the literature for shedding frequency scaling and applying it to various types of finned cylinders in industrial heat exchangers. The focus is on three finned cylinder types: straight, twist-serrated, and crimped spirally finned cylinders. Within each finned cylinder category, at least three different finned cylinders are investigated. The results indicate that utilizing the appropriate equivalent diameter for vortex shedding frequency scaling collapses the data within the Strouhal bounds of a bare cylinder away from resonance excitation. However, the onset of flow-excited acoustic resonance and peak acoustic pressure in all the finned cylinder cases occur at a reduced flow velocity earlier than their equivalent diameter bare cylinder. This suggests that although utilizing the appropriate equivalent diameter can predict the shedding frequency away from resonance, it cannot be used in velocity scaling to predict the onset of acoustic resonance in finned tube bundle.
Technical Basis Summary for Code Case N-860: Inspection Requirements and Evaluation Standards for Spent Nuclear Fuel Storage and Transportation Containment Systems
Authors: Broussard John E.
Published: October 2021

ASME Boiler and Pressure Vessel Code Section XI Code Case N-860 provides inspection requirements and evaluation standard for welded stainless steel canisters used for spent nuclear fuel storage. The Code Case defines an initial inspection interval and populations then defines examination requirements that are based on the primary degradation mechanism, chloride induced stress corrosion cracking (CISCC). Additional examination requirements are based on the results of the initial screening examination. This paper summarizes the technical basis for the examinations and the evaluation criteria defined in Code Case N-860. Technical basis information for topics related to the inservice inspection and the flaw evaluation of canisters are described. The topics related to inservice inspection include: 1) the reasons for and the basis of requirements for the site susceptibility of the canister installations, 2) the inspection intervals required by the Code Case, 3) the inspection sample population required by the Code Case, 4) the methods and acceptance criteria for visual examinations required by the Code Case, and 5) the size and location of the required inspection region for supplemental examinations. The topics related to the flaw evaluation include: 1) a summary of the crack growth rate technical basis, and 2) background related to flaw size evaluation for spent fuel canisters.
Flexural Vibrations of a Multi-Material Microhydraulic Hose Subjected to External Excitation. Experimental Research and Theoretical Description
Authors: Lubecki Marek , Stosiak Michał , Bocian Mirosław , Urbanowicz Kamil
Published: October 2021

The paper presents experimental research and mathematical modeling of flexural vibrations of a composite hydraulic microhose. The tested object was a Polyflex 2020N-013V30 hydraulic microhose, consisting of a braided aramid layer placed in a thermoplastic matrix. The vibrations were induced with an external electromagnetic exciter in the range from 0 Hz to 100 Hz using the sweep function. Using a laser vibrometer, the exciter’s displacement was measured in the above-mentioned range. Long exposure photographs were taken to identify the form of microhose’s vibrations as well as to measure it’s amplitude. The existence of considerable non-linearity in subsequent natural frequencies was shown. At the same time, mathematical simulations were carried out using the Mathematica software. For the analytical description of the object’s vibrations partial differential equations based on the string equation were used. A part responsible for damping in the material was added to the classical equation of the string. The dependence of the values of the stiffness and damping coefficients a on the excitation frequency made it possible to model nonlinearities manifested by the upward shift of higher natural frequencies and the suppression of the amplitudes of successive modes. Further development of the proposed model will allow for modeling the internal pressure in the hose and its effect on transverse vibrations. It will also allow to design of vibrations of composite microhoses and avoid the coupling of these vibrations with external excitations.
Directed Energy Deposition of UNS S31603 Materials by Wire Arc Energy for Nuclear Application
Authors: Ahn HeeSung , Jang YoungSeob , Heo SungHo
Published: October 2021

GMAW (Gas Metal Arc Welding) based Wire Arc Directed Energy Deposition (WA DED) process is one of the key metal Additive Manufacturing (AM) processes. WA DED process with commercial UNS S31603 filler wires, ER316L and ER316LSi, were applied to investigate whether print deposits satisfy the requirements for manufacturing ASME safety class 1 nuclear pressure valve components. Comprehensive chemical, micro-structural, and mechanical test data on ER316L and ER316LSi print deposits were investigated. Mechanical tests include hardness, bend, CVN, room and high temperature tensile up to 525°C. The test results were compared with ASME SA-182 forging and ASME SA-351 casting valve specifications, and ASTM F3184 standard for AM UNS S31603 with powder bed fusion. From this study, it was concluded that the as-print and solution annealed deposits with ER316LSi filler wire were recommended for manufacturing ASME safety class 1 nuclear pressure valve components.
Design of a Pneumatic Growing Robot Inspired to Plants’ Roots
Authors: Bianchi Giovanni , Agoni Aldo , Cinquemani Simone
Published: October 2021

Although plants are usually seen as static organisms, they exhibit a wide range of movements that only in recent years have been considered as a source of inspiration for robots. The motion of roots is one of the most interesting, because they are extraordinary diggers, able to navigate in unstructured environments, finding their way around obstacles. Moreover, root growth is featured by high energy efficiency because they penetrate the soil adding new material at their tip, without moving the already grown part, preventing friction from dissipating energy and reducing the inertia. A robot inspired to roots’ growth could be employed in search and rescue operations or in environmental monitoring. In this work the design of a soft robot inspired to root’s growth is presented. The body of the robot consists of a cylindrical plastic membrane folded inside itself. When air is blown from the base, the body of the robot is inflated, and its tip is everted increasing its length. On the external surface some Velcro stripes are mounted, which keep the membrane folded. Inside the tip a head is mounted, where the mechanism controlling the direction of growth is placed. It consists of a housing for some balloons, which can be inflated selectively, and their expansion exerts a pressure on the external surface able to open the Velcro stripes. The direction of growth is controlled by selecting which balloon to inflate. The robot has been built and a kinematic model of its motion in the plane has been developed and compared with experimental results.
Modulation of Zirconia Ferroelectricity via Crystal Orientation of Pt Electrode
Authors: Zhuang Yong-Xiang , Shieh Jay , Chen Miin-Jang , Lin Hsin-Chih
Published: October 2021

The origin of ferroelectricity and antiferroelectricity in zirconia (ZrO2) ultrathin films has become a topic of great interest in recent years. The normal ferroelectricity in ZrO2 is widely considered to originate from the high-pressure noncentrosymmetric Pca21 orthorhombic (o) phase. While the antiferroelectric-like behavior is regarded as the result of a phase transition from the centrosymmetric and paraelectric P42/nmc tetragonal (t) phase to the ferroelectric o-phase under electrical loading. This study reports an effective technique to selectively produce a ferroelectric or antiferroelectric ZrO2 ultrathin film (∼15 nm) without compositional manipulation. The technique is based on tailoring the crystal orientation of the Pt bottom electrode on which the ZrO2 ultrathin film is deposited. By correlating the results of the XRD, HRTEM, and electric field-polarization (P-E) analyses, it is found that a cubic phase (111)-oriented Pt electrode promotes the textured growth of the ferroelectric o-phase (111) planes in the ZrO2 ultrathin film; while a random-oriented Pt electrode leads to a t-phase dominated system, resulting in an antiferroelectric-like pinched P-E hysteresis. The modulation of ZrO2 ferroelectricity via the crystal orientation of the Pt bottom electrode can be achieved with a low thermal budget (< 400 °C), making it highly favorable for process integration and device scaling in a variety of nanoelectronics and nanoelectromechanical applications.
Finite Element Modeling of Bio Compatible Piezoelectric Actuator for Orthodontic Treatment
Authors: Amiri Nikta , Karami M. Amin
Published: October 2021

This paper presents the finite element modeling and performance evaluation of a biocompatible piezoelectric actuator using polyvinylidene fluoride (PVDF) as an effective way in accelerating teeth movement and shortening of orthodontic treatment. Polyvinylidene fluoride (PVDF) piezoelectric actuators are used as the source of mechanical vibration and energy conversion. The device has a compact design, and can be adjusted on different teeth based on patients’ needs. The finite element model is constructed by using COMSOL Multiphysics to evaluate the effectiveness of the device. The generated force on the targeted teeth for a range of DC voltages are evaluated, and thereafter a parametric study is conducted to evaluate the effect of PVDF actuator properties including its thickness and electrode area. The results show the device can generate 2.2 gr and 8.8 gr at 100 V applied voltage for 1 mm and 4 mm actuator thickness, respectively. For 1mm PVDF thickness at 100 V, the output force increases from 1 gr to 2.2 gr by increasing the active electrode area from 25 % center area to the whole surface area. The generated force of the proposed device on the targeted teeth provides an output force of 0.5 gr to 3.5 gr depending on teeth locations. The present results demonstrate the possibility of using PVDF to design piezoelectric teeth actuators.
Integrated Thin Film Supercapacitor as Multifunctional Sensor System
Authors: Petersen Jan , Geier Sebastian , Wierach Peter
Published: October 2021

Throughout the integration of thin-film supercapacitors into composite structures, it is not only possible to store electric energy, but also to use them as sensor systems for strain detection. This paper describes the integration of thin-film supercapacitors into a glass-fiber composite structure, as well as their analyzation under mechanical load. The results are showing that there is a strong link between the mechanical load and the impedance spectra of the supercapacitor, enabling it to act as strain sensors. To characterize the samples, a four-point bending experiment is used, which features a well-defined constant load scenario with two interesting load states, a tensile and compression state, all in one sample. On each side one structural supercapacitor is integrated, placed far away from the neutral axis near to the outside layer, to be under the highest strain possible. Additionally, the device is placed in between the middle load entry points. During the four-point bending experiment the load is kept constant to run an electrochemical impedance spectroscopy to characterize the supercapacitor. This gives an inside view of what is happening in the supercapacitor. The experiments show a strong relation between the mechanical load and the electrochemical impedance measurements.
Development of a Releasable Snap-Fit Connector Based on Shape Memory Alloy Actuators
Authors: Pagel Kenny , Wiechmann Arne , Drossel Welf-Guntram , Lachmann Lutz
Published: October 2021

Shape Memory Alloy (SMA) based actuator systems provide many advantages compared to conventional actuators and have already successfully established themselves on the market in various applications. The state of the art shows a large number of SMA applications in the field of joining technology. However, these are almost exclusively aimed at providing a reliable, robust but non-detachable connection using the shape memory one-way effect. Approaches to realize a releasable connection for disassembly purposes do not or hardly exist so far.

In the present paper it is investigated how shape memory alloys can be used to design releasable snap-fit connectors. Therefore, the state of the art in the field of snap-fit connectors, particularly the systems used in the automotive sector is discussed in order to find potential applications. Beyond that, the functional structure of snap-fit connectors is analyzed to determine which SMA semi-finished products are particularly suitable for this purpose. Different concepts are evaluated and a preferred variant is derived. For detail development, a numerical study will be carried out to determine the influences of various geometric parameters on the performance of the actuator. This is realized using an SMA Finite Element Analysis (FEA) model based on Auricchio’s approach, which is described in detail. Based on these results appropriately preconditioned SMA semi-finished products are produced and experimentally investigated in order to validate the model. Furthermore, several functional models of releasable snap-fit connectors are produced using additive manufacturing processes thus verifying the approach in experiments.
Simulation-Based Design and Experimental Validation of a Ferroelectret Strain Energy Harvester for Lightweight Structures
Authors: Holzmann Hendrik , Park Ye Ji , Atzrodt Heiko
Published: October 2021

This work covers a novel concept for piezoelectric energy harvesting for the use in lightweight design. It is motivated by a structural strain excitation in an aircraft wing caused by a dynamic pressure. The concept uses piezoelectric electrets, also called ferroelectrets. Ferroelectrets are piezoelectric polymers that show a higher ecological compatibility and a much higher structural flexibility than piezoceramics. The used ferroelectret material for piezoelectric energy conversion is fluorinated ethylene propylene (FEP) assembled in a parallel-tunnel structure that provides high transversal piezoelectric δ31-coefficients. The transformation of strain energy is realized by a metallic mechanism converting a low strain amplitude with a high structural stress to a desired high strain amplitude. Due to low stresses required in the ferroelectret material, the metallic mechanism is designed in a very light way. An analytical model is presented to show the main design parameters and a finite element model is used with the goal of investigating the power output per total energy harvester mass. The model is eventually validated with experimental results. A power output of 344.2 nW and a ratio of power per mass of 302.6 μWkg−1 can be reached for a single harvester under a realistic quasistatic load. For a suggested cluster this can be increased up to 2.6 mW/m2 which is enough to power many devices with a low power consumption.
Towards Clinically-Relevant Shape Memory Alloy Actuated Active Steerable Needle
Authors: Acharya Sharad Raj , Hutapea Parsaoran
Published: October 2021

The targeting error with surgical needles in percutaneous procedures is the major factor that undermines their efficacy. The limitations in trajectory correction to reduce this error during the insertion have motivated researchers to develop actuation mechanisms in needles. The study of shape memory alloy (SMA) wire actuators in needles has gathered significant interest in the past decade because of high strain density, shape memory effect and biocompatibility. An active steerable needle design with an active stylet and a compliant collet is presented. The stylet tip bends by actuating the SMA wire installed on the bending region of the stylet. The bending region is composed of polytetrafluoroethylene (PTFE) polymer attached to the machined portion of the stylet. PTFE has low stiffness and high thermal and electrical insulation that are suitable for active needle applications. The finite element analysis of the actuation of a 3.25 mm diameter active needle model showed 18% greater tip deflection in the air compared to the prototype. By improving the SMA attachment region in the prototype, increased tip deflection as well as reduced needle diameter of 2 mm (14 gauge), which is a medically applicable scale, could be achieved.
Deep level defect spectroscopies of complex oxide surfaces and interfaces
Authors: Zhang Jun , McNicholas Kyle , Balaz Snjezana , Zeng Zhao Quan , Schlom Darrell , Brillson Leonard J.
Published: October 2021

Intrinsic point defects are commonly present in and can strongly affect the electronic properties of complex oxides and their interfaces. The near- and subsurface characterization techniques, depth-resolved cathodoluminescence spectroscopy and surface photovoltage spectroscopy, can measure the density distributions, energy levels, and optical transitions of intrinsic point defects in complex oxides on a near-nanometer scale. These measurements on SrTiO3, BaTiO3, and related materials reveal the sensitivity of intrinsic point defects to growth temperature, mechanical strain, crystal orientation, and chemical interactions. Spatial redistribution of these defects can vary significantly near surfaces and interfaces and can have strong electronic effects. The combination of these deep level spectroscopies along with other advanced characterization techniques provides an avenue to further expand the understanding and control of complex oxide defects in general.
Engineering a Lysin with Intrinsic Antibacterial Activity (LysMK34) by Cecropin A Fusion Enhances Its Antibacterial Properties against Acinetobacter baumannii
Authors: Abdelkader Karim , Gutiérrez Diana , Tamés-Caunedo Héctor , Ruas-Madiedo Patricia , Safaan Amal , Khairalla Ahmed S. , Gaber Yasser , Dishisha Tarek , Briers Yves
Published: October 2021

Phage lysins are a new class of enzyme-based antibiotics that increasingly gain interest. Lysins kill cells through rapid degradation of the peptidoglycan layer, resulting in sudden osmotic lysis.
Competitive Exclusion of Phytopathogenic Serratia marcescens from Squash Bug Vectors by the Gut Endosymbiont
Caballeronia
Authors: Mendiola Sandra Y. , Stoy Kayla S. , DiSalvo Susanne , Wynn Cameron L. , Civitello David J. , Gerardo Nicole M.
Published: October 2021

Insect-microbe symbioses have repeatedly been shown to profoundly impact an insect’s ability to vector pathogens to other hosts. The use of symbiotic microbes to control insect vector populations is of growing interest in agricultural settings.
Genome Mosaicism in Field Strains of Mycoplasma bovis as Footprints of In-Host Horizontal Chromosomal Transfer
Authors: García-Galán Ana , Baranowski Eric , Hygonenq Marie-Claude , Walch Mathilda , Croville Guillaume , Citti Christine , De la Fe Christian , Nouvel Laurent-Xavier
Published: October 2021

Mycoplasma bovis
is a major pathogen of cattle that has significant detrimental effects on economics and animal welfare in cattle rearing worldwide. Understanding the evolution and the adaptative potential of pathogenic mycoplasma species in the natural host is essential to combating them.
Arbuscular Mycorrhizal Tree Communities Have Greater Soil Fungal Diversity and Relative Abundances of Saprotrophs and Pathogens than Ectomycorrhizal Tree Communities
Authors: Eagar Andrew C. , Mushinski Ryan M. , Horning Amber L. , Smemo Kurt A. , Phillips Richard P. , Blackwood Christopher B.
Published: October 2021

Our work explores how differing mycorrhizal associations of temperate hardwood trees (i.e., arbuscular [AM] versus ectomycorrhizal [ECM] associations) affect soil fungal communities by altering the diversity and relative abundance of saprotrophic and plant-pathogenic fungi along natural gradients of mycorrhizal dominance. Because temperate hardwood forests are predicted to become more AM dominant with climate change, studies examining soil communities along mycorrhizal gradients are necessary to understand how these global changes may alter future soil fungal communities and their functional potential.
Streptomyces coelicolor Vesicles: Many Molecules To Be Delivered
Authors: Faddetta Teresa , Renzone Giovanni , Vassallo Alberto , Rimini Emilio , Nasillo Giorgio , Buscarino Gianpiero , Agnello Simonpietro , Licciardi Mariano , Botta Luigi , Scaloni Andrea , Palumbo Piccionello Antonio , Puglia Anna Maria , Gallo Giuseppe
Published: October 2021

Streptomycetes are widely distributed in nature and characterized by a complex life cycle that involves morphological differentiation. They are very relevant in industry because they produce about half of all clinically used antibiotics, as well as other important pharmaceutical products of natural origin.
Streptomyces coelicolor
is a model organism for the study of bacterial differentiation and bioactive molecule production.
S. coelicolor
produces extracellular vesicles which carry many molecules, such as proteins and metabolites, including antibiotics.
Multicenter Evaluation of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy-Based Method for Rapid Identification of Clinically Relevant Yeasts
Authors: Lam Lisa M. T. , Ismail Ashraf A. , Lévesque Simon , Dufresne Simon F. , Cheng Mathew P. , Vallières Émilie , Luong Me-Linh , Sedman Jacqueline , Dufresne Philippe J.
Published: October 2021

Fourier transform infrared (FTIR) spectroscopy has demonstrated applicability as a reagent-free whole-organism fingerprinting technique for both microbial identification and strain typing. For routine application of this technique in microbiology laboratories, acquisition of FTIR spectra in the attenuated total reflectance (ATR) mode simplifies the FTIR spectroscopy workflow, providing results within minutes after initial culture without prior sample preparation.
Management of Cytomegalovirus, Epstein-Barr Virus, and HIV Viral Load Quality Control Data Using Unity Real Time
Authors: Newton Duane W. , Vandepoele Nico , Yundt-Pacheco John C. , Gauthier David , Bachman Michael A.
Published: October 2021

Quality control (QC) rules (Westgard rules) are applied to viral load testing to identify runs that should be reviewed or repeated, but this requires balancing the patient safety benefits of error detection with the cost and inefficiency of false rejection. In this study, we identified the total allowable errors (TEa) from the literature and utilized a commercially available software program (Unity Real Time; Bio-Rad Laboratories) to manage QC data, assess assay performance, and provide QC decision support for both FDA-approved/cleared (Abbott cytomegalovirus [CMV] and HIV viral load) as well as laboratory-developed (Epstein-Barr virus [EBV] viral load) assays.
Interferon Alpha, but Not Interferon Beta, Acts Early To Control Chronic Chikungunya Virus Pathogenesis
Authors: Locke Marissa C. , Fox Lindsey E. , Dunlap Bria F. , Young Alissa R. , Monte Kristen , Lenschow Deborah J.
Published: October 2021

Chikungunya virus (CHIKV) is a reemerging global pathogen with no effective vaccine or antiviral treatment for acute or chronic disease, and the mechanisms underlying chronic disease manifestations remain poorly defined. The significance of our research is in defining IFN-α, but not IFN-β, as an important host regulator of chronic CHIKV pathogenesis that acts within the first 48 h of infection to limit persistent viral RNA and the number of cells that survive CHIKV infection 1 month postinfection.
The HIV-1 Matrix Protein p17 Does Cross the Blood-Brain Barrier
Authors: Caccuri Francesca , Neves Vera , Gano Lurdes , Correia João D. G. , Oliveira Maria Cristina , Mazzuca Pietro , Caruso Arnaldo , Castanho Miguel
Published: October 2021

The percentage of patients affected by HIV-1-associated neurocognitive disorder (HAND) ranges from 30% to 50% of HIV-infected (HIV
+
) patients. The mechanisms leading to HAND development need to be elucidated, but the roles of secreted viral proteins, chemokines, and proinflammatory molecules appear to be clear.
Opposite Effects of Apoptotic and Necroptotic Cellular Pathways on Rotavirus Replication
Authors: Soliman Mahmoud , Seo Ja-Young , Baek Yeong-Bin , Park Jun-Gyu , Kang Mun-Il , Cho Kyoung-Oh , Park Sang-Ik
Published: October 2021

Viral infection usually culminates in cell death through apoptosis, necroptosis, and, rarely, pyroptosis. Necroptosis is a form of programmed necrosis that is mediated by signaling complexes of the receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed-lineage kinase domain-like protein (MLKL).
Multisite Clinical Validation of Isothermal Amplification-Based SARS-CoV-2 Detection Assays Using Different Sampling Strategies
Authors: Desai Kanan T. , Alfaro Karla , Mendoza Laura , Faron Matthew , Mesich Brian , Maza Mauricio , Dominguez Rhina , Valenzuela Adriana , Acosta Chyntia Díaz , Martínez Magaly , Felix Juan C. , Masch Rachel , Smith Jennifer S. , Gabrilovich Sofia , Wu Tracy , Plump Michael , Novetsky Akiva P. , Einstein Mark H. , Douglas Nataki C. , Cremer Miriam , Wentzensen Nicolas
Published: October 2021

Numerous SARS-CoV-2 detection assays have been developed and introduced into the market under emergency use authorizations (EUAs). EUAs are granted primarily based on small studies of analytic sensitivity and specificity with limited clinical validations.
Miocene to modern hydrothermal circulation and high topography during synconvergent extension in the Cordillera Blanca, Peru
Authors: Grambling Tyler A. , Jessup Micah J. , Newell Dennis L. , Methner Katharina , Mulch Andreas , Hughes Cameron A. , Shaw Colin A.
Published: October 2021

The Cordillera Blanca detachment in the highest elevations of the Peruvian Andes has been accommodating synconvergent extension since the late Miocene. Stable isotope analysis of synkinematic mica from its exhumed footwall shear zone provides new constraints on deep meteoric-hydrothermal circulation during ductile deformation and regional paleoelevation. Muscovite and biotite that deformed and/or grew synkinematically in the shear zone have δ2H values of −131‰ to −58‰ and −149‰ to −98‰ (versus Vienna standard mean ocean water, VSMOW), respectively. The δ2H value difference between coexisting muscovite and biotite is consistent with equilibrium fractionation of the same fluid at the same temperature. Calculated δ2H values of water (−107‰ to −78‰) in equilibrium with these micas are indistinguishable from those of present-day, deeply circulated (9–11 km) hot spring waters emanating from the fault. Such low-δ2H fluids indicate circulation of meteoric water to the depths of the brittle-ductile transition that cannot be explained by other mechanisms. Average recharge paleoelevation for water entering the shear zone based on hydrogen isotopes was 3400 + 500/–700 m (1σ). This is near, but ~500 m below, the present-day mean elevation of the catchments feeding modern hot springs of 3965 ± 880 m, and ~700 m below the 4200 + 700/–900 m mean recharge elevation derived from δ2H values of modern surface and thermal water. The consistency between modern and ancient fault-assisted hydrothermal systems and elevation suggests that high topography, steep relief, and meteoric-hydrothermal circulation have persisted throughout the history of the Cordillera Blanca detachment system.
Presumed incipient choroidal melanoma: proposed diagnostic criteria and management
Authors: Jouhi Susanna , Al-Jamal Ranaa T , Täll Martin , Eskelin Sebastian , Kivelä Tero T
Published: October 2021

Aims

To propose diagnostic criteria for a presumed incipient choroidal melanoma based on tumour growth rate and tumour doubling time (TDT) and to describe management of such tumours with transpupillary thermotherapy (TTT).

Methods

Retrospective interventional case series of nine consecutive presumed incipient uveal melanomas diagnosed and treated with TTT in 2010–2017. Growth rate in mm/year and per cent/year in largest basal diameter (LBD) and TDT were compared with published data for uveal melanomas and growing naevi that did not transform to melanoma under long-term follow-up.

Results

The median LBD and thickness were 1.6 mm (range 0.9–2.3) and 0.20 mm (range 0.15–0.29), respectively. The median age was 57 years (range 47–78). Seven tumours were classified as de novo melanomas and two as transformed naevi. The median time from first observation to diagnosis was 3.3 years (range 2.2–7.3), LBD growth rate 0.25 mm/year (range 0.11–0.72) and 34 per cent/year (range 10–1437), and TDT 609 days (range 97–1612). The estimates matched those reported for uveal melanoma (median TDT 521 days, 90th percentile 2192) and exceeded those for growing naevi (median growth rate 0.04 mm/year, 90th percentile 0.12; 1.1 per cent/year, 90th percentile 2.6). The predicted median age at de novo appearance was 51 years (range 32–63). No tumour grew after TTT during a median follow-up of 2.1 years (range 0.6–8.7).

Conclusions

In this series, relative growth rate and TDT best qualified as diagnostic criteria for an incipient choroidal melanoma. Too small for brachytherapy, they could be managed with TTT.
Inner retinal degeneration associated with optic nerve head drusen in pseudoxanthoma elasticum
Authors: Hess Kristina , Raming Kristin , Charbel Issa Peter , Herrmann Philipp , Holz Frank G , Pfau Maximilian
Published: October 2021

Background/aims

To determine the association of age, presence of optic nerve head drusen (ONHD) and number of previous intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections with inner retinal layer thicknesses in patients with pseudoxanthoma elasticum (PXE).

Methods

In this retrospective case–control study, longitudinal spectral-domain optical coherence tomography imaging data from patients with PXE were compared with controls. A custom deep-learning-based segmentation algorithm was trained and validated to quantify the retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL). The association of age, number of anti-VEGF injections and ONHD with the RNFL and GCL thickness in the outer ETDRS subfields as dependent variables was investigated using mixed model regression.

Results

Fourty-eight eyes of 30 patients with PXE were compared with 100 healthy eyes. The mean age was 52.5±12.9 years (range 21.3–68.2) for patients and 54.2±18.7 years (range 18.0–84.5) for controls. In patients, ONHD were visible in 15 eyes from 13 patients and 31 eyes had received anti-VEGF injections. In the multivariable analysis, age (−0.10 µm/year, p<0.001), the diagnosis of PXE (−2.03 µm, p=0.005) and an interaction term between age and the presence of ONHD (−0.20 µm/year, p=0.001) were significantly associated with the GCL thickness. Including the number of intravitreal injections did not improve the model fit. The RNFL thickness was not significantly associated with any of these parameters.

Conclusions

This study demonstrates a significant association of ageing and ONHD with GCL thinning in patients with PXE, but not with the number of anti-VEGF injections. Given the severity of inner retinal degeneration in PXE, a clinical trial investigating neuroprotective therapy warrants consideration.
Non-invasive markers for sudden cardiac death risk stratification in dilated cardiomyopathy
Authors: Pooranachandran Vivetha , Nicolson Will , Vali Zakariyya , Li Xin , Ng G Andre
Published: October 2021

Dilated cardiomyopathy (DCM) is a common yet challenging cardiac disease. Great strides have been made in improving DCM prognosis due to heart failure but sudden cardiac death (SCD) due to ventricular arrhythmias remains significant and challenging to predict. High-risk patients can be effectively managed with implantable cardioverter defibrillators (ICDs) but because identification of what is high risk is very limited, many patients unnecessarily experience the morbidity associated with an ICD implant and many others are not identified and have preventable mortality. Current guidelines recommend use of left ventricular ejection fraction and New York Heart Association class as the main markers of risk stratification to identify patients who would be at higher risk of SCD. However, when analysing the data from the trials that these recommendations are based on, the number of patients in whom an ICD delivers appropriate therapy is modest. In order to improve the effectiveness of therapy with an ICD, the patients who are most likely to benefit need to be identified. This review article presents the evidence behind current guideline-directed SCD risk markers and then explores new potential imaging, electrophysiological and genetic risk markers for SCD in DCM.
Spatially resolved analysis of the T cell immune contexture in lung cancer-associated brain metastases
Authors: Lu Benjamin Y , Gupta Richa , Aguirre-Ducler Adam , Gianino Nicole , Wyatt Hailey , Ribeiro Matthew , Chiang Veronica L , Contessa Joseph N , Adeniran Adebowale J , Jilaveanu Lucia B , Kluger Harriet M , Schalper Kurt A , Goldberg Sarah B
Published: October 2021

Despite unique genetic alterations within brain metastases (BrMs) and an immunologically distinct surrounding microenvironment, the composition and functional properties of tumor-infiltrating lymphocytes within BrM remain largely unexplored. In particular, the expression of coinhibitory receptors, such as programmed cell death 1 (PD-1), T cell immunoglobulin mucin receptor 3 (TIM-3), and lymphocyte activation gene 3 (LAG-3), within BrMs is unknown. Using multiplexed quantitative immunofluorescence (QIF), this study evaluates the localized expression of PD-L1, level and functional profile of major T cell subsets, and coinhibitory receptors within lung cancer-associated BrMs and primary lung tumors. Clinicopathologically annotated samples from 95 patients with lung cancer between 2002 and 2015 were represented in a tissue microarray format. Spatially resolved and multiplexed QIF was used to evaluate PD-L1 protein, phenotype markers for major T cell subsets (CD3, CD4, CD8, and FOXP3), cell-localized activation and proliferation markers (granzyme B and Ki67), and coinhibitory receptors (PD-1, LAG-3, and TIM-3). The signal for each marker was measured in marker-selected tissue compartments, and associations between marker levels, tumor location, and major clinicopathological variables were studied. In total, 41 primary lung tumors and 65 BrMs were analyzed, including paired samples from 11 patients. Levels of tumor PD-L1 expression were comparable between BrMs and primary lung tumors. BrMs had significantly lower levels of all T cell subsets relative to primary lung tumors, and T cells in BrMs displayed lower levels of granzyme B than primary lesions. PD-1, TIM-3, and LAG-3 levels in CD3+T-cells were also significantly lower in BrMs. Marker expression in patients with paired samples from BrMs and primary lung tumors showed comparable results. High CD3+T-cells, as well as high levels of TIM-3 and LAG-3 in CD3+T-cells, were associated with longer overall survival in BrMs but not primary lung tumors. Lung cancer-associated BrMs display lower T cell infiltration, markers of cytolytic function, and immune regulatory signals than primary lung tumors. Despite these differences, high TIM-3 and high LAG-3 expressions in CD3+T-cells were associated with longer survival. These features are accompanied by comparable levels of PD-L1 protein expression compared with primary lung tumors. These results highlight unique aspects of the tumor immune microenvironment within the brain and provide further support for intracranially focused therapies.
Gaussian quantum steering under the influence of a dilaton black hole
Authors: Hu Biwei , Wen Cuihong , Wang Jieci , Jing Jiliang
Published: October 2021

We study the dynamics of Gaussian quantum steering in the background of a Garfinkle–Horowitz–Strominger dilaton black hole. It is found that the gravity induced by dilaton field will destroy the quantum steerability between the inertial observer Alice and the observer Bob who hovers outside the event horizon, while it generates steering-type quantum correlations between the causally disconnected regions. Therefore, the observers can steer each other’s state by local measurements even though they are separated by the event horizon. Unlike quantum entanglement in the dilaton spacetime, the quantum steering experiences catastrophic behaviors such as “sudden death” and “sudden birth” with increasing dilaton charge. In addition, the dilaton gravity destroys the symmetry of Gaussian steering and the latter is always asymmetric in the dilation spacetime. Interestingly, the attainment of maximal steering asymmetry indicates the critical point between one-way and two-way steering for the two-mode Gaussian state in the dilaton spacetime.
Quantum interference and imaging using intense laser fields
Authors: Amini Kasra , Chacón Alexis , Eckart Sebastian , Fetić Benjamin , Kübel Matthias
Published: October 2021

The interference of matter waves is one of the intriguing features of quantum mechanics that has impressed researchers and laymen since it was first suggested almost a century ago. Nowadays, attosecond science tools allow us to utilize it in order to extract valuable information from electron wave packets. Intense laser fields are routinely employed to create electron wave packets and control their motion with attosecond and ångström precision. In this perspective article, which is based on our debate at the Quantum Battles in Attoscience virtual workshop 2020, we discuss some of the peculiarities of intense light-matter interaction. We review some of the most important techniques used in attosecond imaging, namely photoelectron holography and laser-induced electron diffraction. We attempt to ask and answer a few questions that do not get asked very often. For example, if we are interested in position space information, why are measurements carried out in momentum space? How to accurately retrieve photoelectron spectra from the numerical solution of the time-dependent Schrödinger equation? And, what causes the different coherence properties of high-harmonic generation and above-threshold ionization?

GraphicAbstract
Extension of perturbation theory to quantum systems with conformable derivative
Authors: Al-Masaeed Mohamed , Rabei Eqab M , Al-Jamel Ahmed , Baleanu Dumitru
Published: October 2021

In this paper, the perturbation theory is extended to be applicable for systems containing conformable derivative of fractional order [Formula: see text]. This is needed as an essential and powerful approximation method for describing systems with conformable differential equations that are difficult to solve analytically. The work here is derived and discussed for the conformable Hamiltonian systems that appears in the conformable quantum mechanics. The required [Formula: see text]-corrections for the energy eigenvalues and eigenfunctions are derived. To demonstrate this extension, three illustrative examples are given, and the standard values obtained by the traditional theory are recovered when [Formula: see text].