bluuebunny/crossref_metadata_2025 huggingface dataset:
Extracellular Matrix-Based Biomaterials for Cardiovascular Tissue Engineering
Authors: Khanna Astha , Zamani Maedeh , Huang Ngan F.
Published: October 2021

Regenerative medicine and tissue engineering strategies have made remarkable progress in remodeling, replacing, and regenerating damaged cardiovascular tissues. The design of three-dimensional (3D) scaffolds with appropriate biochemical and mechanical characteristics is critical for engineering tissue-engineered replacements. The extracellular matrix (ECM) is a dynamic scaffolding structure characterized by tissue-specific biochemical, biophysical, and mechanical properties that modulates cellular behavior and activates highly regulated signaling pathways. In light of technological advancements, biomaterial-based scaffolds have been developed that better mimic physiological ECM properties, provide signaling cues that modulate cellular behavior, and form functional tissues and organs. In this review, we summarize the in vitro, pre-clinical, and clinical research models that have been employed in the design of ECM-based biomaterials for cardiovascular regenerative medicine. We highlight the research advancements in the incorporation of ECM components into biomaterial-based scaffolds, the engineering of increasingly complex structures using biofabrication and spatial patterning techniques, the regulation of ECMs on vascular differentiation and function, and the translation of ECM-based scaffolds for vascular graft applications. Finally, we discuss the challenges, future perspectives, and directions in the design of next-generation ECM-based biomaterials for cardiovascular tissue engineering and clinical translation.
Evaluation of the Efficacy and Safety of Canaloplasty and iStent Bypass Implantation in Patients with Open-Angle Glaucoma: A Review of the Literature
Authors: Gołaszewska Kinga , Konopińska Joanna , Obuchowska Iwona
Published: October 2021

The aim of the paper was to evaluate the efficacy and safety of minimally invasive antiglaucoma procedures: Canaloplasty and iStent bypass implantation with and without phacoemulsification in patients with primary open-angle glaucoma (POAG). A systematic review of the recent literature was performed based on the PubMed, Google Scholar, Web of Science and Scopus databases. The effectiveness of the procedures was evaluated based on the reduction of intraocular pressure (IOP) and the amount of antiglaucoma medication used before and after surgery. Safety of the treatments was evaluated based on the number of incidences of certain intraoperative and postoperative complications. Independent prospective randomized controlled trials (PRCTs) have demonstrated that both procedures, canaloplasty and iStent implantation, are effective in reducing IOP and the amount of antiglaucoma medication. Considering the safety profile of these procedures, both canaloplasty and iStent implantation are associated with low rates of postoperative complications and have similar safety profiles. Further studies are needed to confirm the results of our analysis, including a high-quality randomized controlled trial comparing canaloplasty and iStent bypass implantation
Do Not Miss the (Genetic) Diagnosis of Gaucher Syndrome: A Narrative Review on Diagnostic Clues and Management in Severe Prenatal and Perinatal-Lethal Sporadic Cases
Authors: Jezela-Stanek Aleksandra , Kleinotiene Grazina , Chwialkowska Karolina , Tylki-Szymańska Anna
Published: October 2021

With a growing number of proved therapies and clinical trials for many lysosomal storage disorders (LSDs), a lot of hope for many patients and families exists. However, there are sometimes cases with poor prognosis, fatal outcomes when our efforts must be directed towards a prompt and correct genetic diagnosis, which offers the only possibility of providing the family with appropriate prevention and treatment. To address this issue, in this article, we present the clinical and genetic hallmarks of the lethal form of Gaucher disease (PLGD) and discuss the potential management. We hope that this will draw attention to its specific manifestations (such as collodion-baby phenotype, ichthyosis, arthrogryposis), which differ from best-known GD complications and ensure appropriate diagnostic assessment to provide families at risk with reliable counselling and treatment to avoid the medical complication of GD.
A Randomised-Controlled Clinical Study Examining the Effect of High-Intensity Laser Therapy (HILT) on the Management of Painful Calcaneal Spur with Plantar Fasciitis
Authors: Tkocz Piotr , Matusz Tomasz , Kosowski Łukasz , Walewicz Karolina , Argier Łukasz , Kuszewski Michał , Hagner-Derengowska Magdalena , Ptaszkowski Kuba , Dymarek Robert , Taradaj Jakub
Published: October 2021

Calcaneal spur and plantar fasciitis are the most common causes of plantar heel pain. There are many effective physical modalities for treating this musculoskeletal disorder. So far, the are no clear recommendations confirming the clinical utility of high-intensity laser therapy (HILT) in the management of painful calcaneal spur with plantar fasciitis. This study aimed to evaluate the effectiveness of HILT in pain management in patients with calcaneal spur and plantar fasciitis. A group of 65 patients was assessed for eligibility based on the CONSORT guidelines. This study was prospectively registered in the Australian New Zealand Clinical Trial Registry platform (registration number ACTRN12618000744257, 3 May 2018). The main eligibility criteria were: cancer, pregnancy, electronic and metal implants, acute infections, impaired blood coagulation, cardiac arrhythmias, taking analgesic or anti-inflammatory medications, non-experience of heel pain, or presence of other painful foot conditions. Finally, 60 patients were randomly assigned into two groups: study group (n = 30, mean age 59.9 ± 10.1), treated with HILT (7 W, 149.9 J/cm2, 1064 nm, 4496 J, 12 min), and placebo-controlled group (n = 30, mean age 60.4 ± 11.9), treated with sham HILT therapy. Both groups received ultrasound treatments (0.8 W/cm2, 1 MHz frequency, 100% load factor, 5 min). Treatment procedures were performed once a day, five times per week for three weeks (total of 15 treatment sessions). Study outcomes focused on pain intensity and were assessed before (M1) and after (M2) the treatment as well as after 4 (M3) and 12 (M4) weeks using the Visual Analogue Scale (VAS) and the Laitinen Pain Scale (LPS). According to VAS, a statistically significant decrease in the study group was observed between M1 and M2 by 3.5 pts, M1 and M3 by 3.7 pts, and M1 and M4 by 3.2 pts (p < 0.001). On the other hand, the control group showed a statistically significant decrease (p < 0.001) between M1 and M2 by 3.0 pts, M1 and M3 by 3.4 pts, and M1 and M4 by 3.2 pts. According to LPS, a statistically significant decrease in the study group was observed between M1 and M2 by 3.9 pts, M1 and M3 by 4.2 pts, and M1 and M4 by 4.0 pts (p < 0.001). On the other hand, the control group showed a statistically significant decrease between M1 and M2 by 3.2 pts (p = 0.002), M1 and M3 by 4.0 pts (p < 0.001), and M1 and M4 by 3.9 pts (p < 0.001). However, there were no statistically significant differences between the groups in VAS and LPS (p > 0.05). In conclusion, the HILT does not appear to be more effective in pain management of patients with calcaneal spurs and plantar fasciitis than the conservative standard physiotherapeutic procedures.
Type D Personality and Stomatognathic System Disorders in Physiotherapy Students during the COVID-19 Pandemic
Authors: Gębska Magdalena , Dalewski Bartosz , Pałka Łukasz , Kołodziej Łukasz , Sobolewska Ewa
Published: October 2021

Background: A person’s response to stressors is largely dependent on their personality traits that affect the way stress is controlled and relieved. This article is a quantitative analysis assessing the importance of the distressed personality in the development of stomatognathic system disorders (SSDs) in physiotherapy students during the COVID-19 pandemic. Objective: The goal of the research was to assess the presence of type D personality in students with symptoms of stomatognathic system disorders. Material and Method: The research was carried out among 300 physiotherapy students. The data were collected using the form of the occurrence of symptoms of SS disorders developed for the purpose of the study and the standardized psychological DS14 questionnaire. Results: In a group of 300 students, the presence of type D personality was found in 160 people (53.3%). People with type D personality had symptoms of SS disorders more often than the group without stressful personality traits. There was a significant difference between the groups regarding all the examined symptoms. In the group of people with type D personality, the most frequently reported symptoms of SS disorders included: headache (51.3%), pain in the neck and shoulder girdle (43.1%), and teeth clenching (35.6%). As many as 70% of the respondents in the group with symptoms of SS disorders (P1) had type D personality, whereas in the asymptomatic group (P2) this result was 23.3%. There was a significant difference between the groups (p = 0.00). Statistically significantly higher values of both D personality dimensions were observed in women than in men with symptoms of SS disorders. In people reporting symptoms of SS disorders, higher average values were observed in both dimensions of type D personality. There were significant differences between the groups. Conclusion: type D personality may contribute to the development of symptoms of stomatognathic disorders.
The Influence of Missing Data on Disabilities in Patients Treated with High-Dose Spinal Cord Stimulation: A Tipping Point Sensitivity Analysis
Authors: Goudman Lisa , Molenberghs Geert , Duarte Rui V. , Moens Maarten
Published: October 2021

New waveforms have changed the field of Spinal Cord Stimulation (SCS) to optimize therapy outcomes, among which is High-Dose SCS (HD-SCS). Missing observations are often encountered when conducting clinical trials in this field. In this study, different approaches with varying assumptions were constructed to evaluate how conclusions may be influenced by these assumptions. The aim is to perform a tipping point sensitivity analysis to evaluate the influence of missing data on the overall conclusion regarding the effectiveness of HD-SCS on disability. Data from the Discover study were used, in which 185 patients with Failed Back Surgery Syndrome were included. Disability was evaluated before SCS and after 1, 3 and 12 months of HD-SCS. During the second, third and fourth visit, data from 130, 114 and 90 patients were available, respectively. HD-SCS resulted in a significant decrease in disability scores based on the analysis of observed data and with multiple imputations. The tipping point sensitivity analysis revealed that the shift parameter was 17. Thus, the conclusion concerning the time effect under a “missing at random” mechanism is robust when the shift parameter for the disability score is 17. From a clinical point of view, a shift of 17 points on disability is not very plausible. Therefore we tend to consider the conclusions drawn under “missing at random” as being robust.
Preoperative versus Postoperative Compensation of the Contralateral Normal Kidney in Patients Treated with Radical Nephrectomy for Renal Cell Carcinoma
Authors: Lee Chung-Un , Ryoo Hyunsoo , Chung Jae-Hoon , Song Wan , Kang Minyong , Sung Hyun-Hwan , Jeong Byong-Chang , Seo Seong-Il , Jeon Seong-Soo , Lee Hyun-Moo , Jeon Hwang-Gyun
Published: October 2021

Background: We sought to identify the factors affecting renal compensatory processes that occur preoperatively as well as postoperatively in patients treated with radical nephrectomy (RNx) for renal cell carcinoma (RCC). Methods: We retrospectively reviewed the records of 906 patients treated with RNx for RCC. We defined the early compensatory process (process 1) as compensatory adaptation of the contralateral normal kidney (CNK) before RNx. We defined the late compensatory process (process 2) as compensatory adaptation of the CNK after RNx. Total compensation was defined as the combination of these two processes. Multivariable logistic regression analyses were used to identify significant factors associated with processes 1, 2 and total compensation. Results: Mean preoperative, 1-week, and 5-year postoperative estimated glomerular filtration rates (eGFR) were 84.5, 57.6 and 63.7 mL/min/1.73 m2, respectively. Female sex (p < 0.001), lower body mass index (BMI) (p < 0.001), absence of hypertension (p = 0.019), lower preoperative eGFR (p < 0.001), larger tumor volume (p < 0.001), and larger CNK volume (p < 0.001) were significantly associated with process 1. Younger age (p = 0.019), higher BMI (p < 0.001), and absence of diabetes mellitus (DM) (p = 0.033) were significantly associated with process 2. Female sex (p < 0.001), younger age (p < 0.001), absence of DM (p = 0.002), lower preoperative eGFR (p < 0.001), and larger tumor (p = 0.001) and CNK volumes (p < 0.001) were significantly associated with total compensation. Conclusions: Different factors affected each compensatory process. Process 1 made a greater contribution to the entire renal compensatory process than process 2.
Ionospheric Clutter Suppression with an Auxiliary Crossed-Loop Antenna in a High-Frequency Radar for Sea Surface Remote Sensing
Authors: He Shuqin , Zhou Hao , Tian Yingwei , Shen Wei
Published: October 2021

Ionospheric clutter is one of the main problems for high-frequency surface wave radars (HFSWRs), as it severely interferes with sea surface state monitoring and target detection. Although a number of methods exist for ionospheric clutter suppression, most are suitable for radars with a large-sized array and are inefficient for small-aperture radars. In this study, we added an auxiliary crossed-loop antenna to the original compact radar antenna, and used an adaptive filter to suppress the ionospheric clutter. The experimental results of the HFSWRs data indicated that the suppression factor of the ionospheric clutter was up to 20 dB. Therefore, the Bragg peaks that were originally submerged by the ionospheric clutters could be recovered, and the gaps in the current maps can, to a large extent, be filled. For an oceanographic radar, the purpose of suppressing ionospheric clutter is to extract an accurate current speed; the radial current fields that were generated by our method showed an acceptable agreement with those generated by GlobCurrent data. This result supports the notion that the ionospheric suppression technique does not compromise the estimation of radial currents. The proposed method is particularly efficient for a compact HFSWRs, and can also be easily used in other types of antennas.
Numerical Study on the Massive Outbreak of the Ulva prolifera Green Tides in the Southwestern Yellow Sea in 2021
Authors: Wang Bin , Wu Lei
Published: October 2021

The most massive outbreak on record of the Ulva prolifera green tides in the southwestern Yellow Sea occurred in summer of 2021. The environmental factors were investigated based on observations and simulations. The results suggested that the significantly enhanced discharge of the Changjiang River since winter 2020–2021 was crucial for the outbreak of the Ulva prolifera green tides in the southwestern Yellow Sea, which could significantly have contributed to the nutrient enrichment off the Subei coast. Additionally, the southerly wind stress anomaly during winter 2020–2021 favored the upwind transport of Changjiang water. Numerical experiments showed that the remaining winter freshwater coming from the Changjiang River, which persisted in the Subei coast’s upper layer until spring 2021, exceeded the long-term average value by 20%. We demonstrated that these large amount of nutrient inputs, as an effective supplement, were the reason the green tides sharply emerged as an extensive outbreak in 2021. The easterly wind anomaly during spring 2021 contributed to the landing of Ulva prolifera off the Lunan coast.
Mining Early Life Risk and Resiliency Factors and Their Influences in Human Populations from PubMed: A Machine Learning Approach to Discover DOHaD Evidence
Authors: Tewari Shrankhala , Toledo Margalef Pablo , Kareem Ayesha , Abdul-Hussein Ayah , White Marina , Wazana Ashley , Davidge Sandra T. , Delrieux Claudio , Connor Kristin L.
Published: October 2021

The Developmental Origins of Health and Disease (DOHaD) framework aims to understand how early life exposures shape lifecycle health. To date, no comprehensive list of these exposures and their interactions has been developed, which limits our ability to predict trajectories of risk and resiliency in humans. To address this gap, we developed a model that uses text-mining, machine learning, and natural language processing approaches to automate search, data extraction, and content analysis from DOHaD-related research articles available in PubMed. Our first model captured 2469 articles, which were subsequently categorised into topics based on word frequencies within the titles and abstracts. A manual screening validated 848 of these as relevant, which were used to develop a revised model that finally captured 2098 articles that largely fell under the most prominently researched domains related to our specific DOHaD focus. The articles were clustered according to latent topic extraction, and 23 experts in the field independently labelled the perceived topics. Consensus analysis on this labelling yielded mostly from fair to substantial agreement, which demonstrates that automated models can be developed to successfully retrieve and classify research literature, as a first step to gather evidence related to DOHaD risk and resilience factors that influence later life human health.
Psychological Stress and Salivary Cortisol Levels in Patients with Plaque Psoriasis
Authors: Gisondi Paolo , Geat Davide , Bellinato Francesco , Spiazzi Laura , Danese Elisa , Montagnana Martina , Lippi Giuseppe , Girolomoni Giampiero
Published: October 2021

Psychological stress has long been recognized as a trigger for plaque psoriasis, and preliminary evidence suggests that psoriasis could be associated with alterations in the hypothalamic-pituitary-adrenal (HPA) axis, resulting in impaired cortisol response to stress. This study aimed to investigate psychological stress, anxiety, depression and salivary cortisol in psoriatic patients. A cross sectional study involving 126 adult patients with plaque psoriasis and 116 adult healthy controls was conducted. Demographic, clinical data, Perceived Stress Scale (PSS) and Hospital Anxiety and Depression Scale (HADS) were collected. Cases and controls were asked whether they felt stressed in the last month, whilst psoriatic patients were also interrogated whether they found that psoriasis could have been worsened by stress. Moreover, 54 randomly selected subjects (27 psoriasis patients and 27 controls) underwent salivary cortisol testing at 8 am. PSS, HADS depression and anxiety subscales were significantly higher in psoriatic patients than in controls (17.2 ± 0.6 vs. 15.1 ± 0.8 p = 0.0289), (9.5 ± 0.3 vs. 6.2 ± 0.3 p < 0.001) and (8.2 ± 0.4 vs. 4.2 ± 0.3 p < 0.001), respectively. A higher rate of psoriatic patients reported feeling stress over the last month (45% vs. 19%, p < 0.001), and stress was considered a potential trigger for psoriasis flare-ups in 69% of cases. Psoriasis was strongly associated with higher PSS and HADS scores independently of sex, body mass index, diabetes, hypertension, dyslipidemia, and occupational status. Salivary cortisol was significantly lower in psoriatic patients compared to controls (9.6 ± 0.5 vs. 14.0 ± 1.1 nmol/L, p < 0.001). In conclusion, psoriasis was associated with higher psychological stress, anxiety and depressive symptoms, and with impaired cortisol response to stress.
Study of the Operation Process of the E-Commerce Oriented Ecosystem of 5Ge Base Station, Which Supports the Functioning of Independent Virtual Network Segments
Authors: Kovtun Viacheslav , Izonin Ivan
Published: October 2021

According to specifications, flexible services for traffic management should be implemented within the 5G platform in order to improve its efficiency, which is and will remain an actual task. For the first time, the article presented here proposes a mathematical model for the operation process of an e-commerce-oriented ecosystem of a 5Ge base station, the information environment of which supports the operation of independent virtual network segments that provide terminal–segment information interaction services. In contrast to existing models, the presented model describes the studied process as a multi-pipeline queuing system, the inputs of which are coordinated with the flows of requests for communication with the relevant virtual network segments. The distribution of the total resources between the weighted virtual network segments in the simulated system is dynamically conducted by the appropriate software control mechanism. It considers the address intensities of new incoming requests and the maintenance of received incoming requests, but throughout the scale of the information environment of the 5Ge base station ecosystem. Based on the created mathematical model, a functional algorithm for the forced termination of an active terminal–segment information interaction session in the overloaded virtual network segment and the control mechanism of the distribution of the released system resources between other virtual network segments that takes into account the degree of their overload are formulated. The simulation and computational experiments showed that the implemented forced termination algorithm and system resource management mechanism allow the 5Ge base station to continue receiving incoming requests despite the overload of individual virtual network segments. It is empirically shown that the proposed services are effectively scaled concerning the value that is generally available for the distribution of the number of system resources and the allocation method within the guaranteed amounts of system resources for individual virtual network segments.
Ecosystem Services for Scenic Quality Landscape Management: A Review
Authors: Smardon Richard
Published: October 2021

Since the Millennium Ecosystem Assessment Project proposed the valuation of ecosystem services—defined as regulatory, provisional, ecosystem and cultural—the question arises as to the utility of such assessments for scenic landscape management. This author as well as others has looked at the issue of integrating ecological concerns with landscape planning. This article will be a comprehensive literature review and analysis of issues involved with utilizing ecosystem services of assessment of scenic/visual landscape quality as well as management implications. Special emphasis will be placed on the role of cultural ecosystem services.
Pollution Characteristics, Spatial Patterns, and Sources of Toxic Elements in Soils from a Typical Industrial City of Eastern China
Authors: Xia Fang , Zhu Youwei , Hu Bifeng , Chen Xueyao , Li Hongyi , Shi Kejian , Xu Liuchang
Published: October 2021

Soil pollution due to toxic elements (TEs) has been a core environmental concern globally, particularly in areas with developed industries. In this study, we sampled 300 surface (0–0.2 m) soil samples from Yuyao City in eastern China. Initially, the geo-accumulation index, potential ecological risk index, single pollution index, and Nemerow composite pollution index were used to evaluate the soil contamination status in Yuyao City. Ordinary kriging was then deployed to map the distribution of the soil TEs. Subsequently, indicator kriging was utilized to identify regions with high risk of TE pollution. Finally, the positive matrix factorization model was used to apportion the sources of the different TEs. Our results indicated that the mean content of different TEs kept the order: Zn > Cr > Pb > Cu > Ni > As > Hg ≈ Cd. Soil pollution was mainly caused by Cd and Hg in the soil of Yuyao City, while the content of other TEs was maintained at a safe level. Regions with high TE content and high pollution risk of TEs are mainly located in the central part of Yuyao City. Four sources of soil TEs were apportioned in Yuyao City. The Pb, Hg, and Zn contents in soil were mainly derived from traffic activities, coal combustion, and smelting. Meanwhile, Cu was mainly sourced from industrial emissions and atmospheric deposition, Cr and Ni mainly originated from soil parental materials, and Cd and As were produced by industrial and agricultural activities. Our study provides important implications for improving the soil environment and contributes to the development of efficient strategies for TE pollution control and remediation.
Clostridioides difficile and Vancomycin-Resistant Enterococci in COVID-19 Patients with Severe Pneumonia
Authors: Bogdanová Kateřina , Doubravská Lenka , Vágnerová Iva , Hricová Kristýna , Pudová Vendula , Röderová Magdaléna , Papajk Jan , Uvízl Radovan , Langová Kateřina , Kolář Milan
Published: October 2021

Broad-spectrum antibiotics administered to patients with severe COVID-19 pneumonia pose a risk of infection caused by Clostridioides difficile. This risk is reduced mainly by strict hygiene measures and early de-escalation of antibiotic therapy. Recently, oral vancomycin prophylaxis (OVP) has also been discussed. This retrospective study aimed to assess the prevalence of C. difficile in critical COVID-19 patients staying in an intensive care unit of a tertiary hospital department of anesthesiology, resuscitation, and intensive care from November 2020 to May 2021 and the rates of vancomycin-resistant enterococci (VRE) after the introduction of OVP and to compare the data with those from controls in the pre-pandemic period (November 2018 to May 2019). During the COVID-19 pandemic, there was a significant increase in toxigenic C. difficile rates to 12.4% of patients, as compared with 1.6% in controls. The peak rates were noted in February 2021 (25% of patients), immediately followed by initiation of OVP, changes to hygiene precautions, and more rapid de-escalation of antibiotic therapy. Subsequently, toxigenic C. difficile detection rates started to fall. There was a nonsignificant increase in VRE detected in non-gastrointestinal tract samples to 8.9% in the COVID-19 group, as compared to 5.3% in the control group. Molecular analysis confirmed mainly clonal spread of VRE.
New Insight to Overcome Tumor Resistance: An Overview from Cellular to Clinical Therapies
Authors: Mitola Giulia , Falvo Paolo , Bertolini Francesco
Published: October 2021

Disease relapse caused by drug resistance still represents a major clinical hurdle in cancer treatments. Tumor cells may take advantage of different intracellular and genetic systems attenuating the drug effects. Resistant cells or minimal residual disease (MRD) cells have strong clinical relevance, as they might give rise to secondary tumors when the therapy is concluded. Thus, MRDs are crucial therapeutic targets in order to prevent tumor relapse. Therefore, several groups aim at understanding how MRDs are orginated, characterizing their molecular features, and eradicating them. In this review, we will describe MRD from a genetic, evolutionary, and molecular point of view. Moreover, we will focus on the new in vitro, in vivo, preclinical, and clinical studies that aim at eradicating tumor resistance.
Research on Thermal Characteristics of Ball Screw Feed System Considering Nut Movement
Authors: Liu Hongliang , Rao Zhaofeng , Pang Ruda , Zhang Yaoman
Published: October 2021

The heat generated by the ball screw feed system will produce thermal errors, which will cause the positioning accuracy to decrease. The thermal simulation modeling of the ball screw feed system is the basis for compensating thermal errors. The current thermal characteristic modeling method simplifies the reciprocating movement of the nut pair on the screw shaft to varying degrees, which leads to a decrease in simulation accuracy. In this paper, the nut is regarded as a moving heat source, and a novel method is adopted to make the moving process of the heat source closer to the actual nut movement process. The finite difference method is used to simulate the temperature field and thermal error of the ball screw feed system under different working conditions. Firstly, based on the heat transfer theory, the heat conduction differential equation of the feed system is established and discretized. The thermal error model of the ball screw feed system is established. Then, the relationship between nut heat source position and operating time is established to simulate nut reciprocating motion. Finally, the temperature and thermal error experiments of the ball screw feed system were carried out, and the temperature experiment results were compared with the simulation results of the finite difference method. The results show that the maximum simulation error of the average temperature in the operating interval is 11.4%, and the maximum simulation error of thermal error is 16.4%, which verifies the validity and correctness of the method. The thermal characteristic modeling method of the ball screw feed system proposed in this paper has a substantial application value for accurately obtaining the temperature field of the feed system.
Lines of Curvature for Log Aesthetic Surfaces Characteristics Investigation
Authors: Gobithaasan R.U. , Teh Yee , Miura Kenjiro , Ong Wen
Published: October 2021

Lines of curvatures (LoCs) are curves on a surface that are derived from the first and second fundamental forms, and have been used for shaping various types of surface. In this paper, we investigated the LoCs of two types of log aesthetic (LA) surfaces; i.e., LA surfaces of revolution and LA swept surfaces. These surfaces are generated with log aesthetic curves (LAC) which comprise various families of curves governed by α. First, since it is impossible to derive the LoCs analytically, we have implemented the LoC computation numerically using the Central Processing Unit (CPU) and General Processing Unit (GPU). The results showed a significant speed up with the latter. Next, we investigated the curvature distributions of the derived LoCs using a Logarithmic Curvature Graph (LCG). In conclusion, the LoCs of LA surface of revolutions are indeed the duplicates of their original profile curves. However, the LoCs of LA swept surfaces are LACs of different shapes. The exception to this is when this type of surface possesses LoCs in the form of circle involutes.
Past, Present and Future of Membrane Technology in Spain
Authors: Calvo José I. , Casado-Coterillo Clara , Hernández Antonio
Published: October 2021

The following review aims at analyzing the contribution of Spanish researchers to membrane science and technology, with a historical compilation of the main milestones. We used a bibliometric analysis based on the Scopus database (1960–2020) dealing with 8707 documents covering the different disciplines and subject areas where membranes are involved. Furthermore, the information has been updated to the present moment of writing this manuscript in order to include the latest research lines and the different research groups currently active in Spain, which may lead the way to the development of the field in the coming years.
Very High Cycle Fatigue Investigations on the Fatigue Strength of Additive Manufactured and Conventionally Wrought Inconel 718 at 873 K
Authors: Schmiedel Alexander , Burkhardt Christina , Henkel Sebastian , Weidner Anja , Biermann Horst
Published: October 2021

The fatigue lives of additively manufactured (AM) Inconel 718 (IN718) produced by selective electron beam melting and conventional wrought material as reference conditions were studied in the very high cycle fatigue regime under fully reversed loading (R = −1) at the elevated temperature of 873 K using an ultrasonic fatigue testing system. The fatigue lives of the AM material were significantly reduced compared to the wrought material, which is discussed in relation to the microstructure and a fractographical analysis. The additively manufactured material showed large columnar grains with a favoured orientation to the building direction and porosity, whereas the wrought material showed a fine-grained structure with no significant texture, but had Nb- and Ti-rich non-metallic inclusions. Crystallographic crack initiation as well as crack initiation from the surface or internal defects were observed for the AM and the wrought IN718, respectively.
Two-Intervals Hardening Function in a Phase-Field Damage Model for the Simulation of Aluminum Alloy Ductile Behavior
Authors: Dunić Vladimir , Živković Jelena , Milovanović Vladimir , Pavlović Ana , Radovanović Andreja , Živković Miroslav
Published: October 2021

The aluminum alloys (AA) are among the most utilized materials in engineering structures, which induces the need for careful investigation, testing, and possibilities for accurate simulation of the structure’s response. AA 5083-H111 specimens were used to investigate the possibility of employing a Phase-Field Damage Model (PFDM) for the simulation of AA structures’ behavior. The specimens were mechanically tested by uniaxial tensile loading tests. Based on the obtained results, the PFDM was employed with a von Mises plasticity model, implemented in the Finite Element Method software. The plasticity model was extended by modification of the hardening function defined in two-intervals: a linear hardening and a Simo-type hardening. An excellent superposition of the simulation and experimental force-displacement response was recorded. These findings suggest that the AA structures’ response can be successfully simulated in the elastic-plastic domain, as well as its failure by damage being controlled.
On the Limitations of Positron Annihilation Spectroscopy in the Investigation of Ion-Implanted FeCr Samples
Authors: Slugen Vladimir , Degmova Jarmila , Sojak Stanislav , Petriska Martin , Noga Pavol , Krsjak Vladimir
Published: October 2021

New materials for advanced fission/fusion nuclear facilities must inevitably demonstrate resistance to radiation embrittlement. Thermal and radiation ageing accompanied by stress corrosion cracking are dominant effects that limit the operational condition and safe lifetime of the newest nuclear facilities. To study these phenomena and improve the current understanding of various aspects of radiation embrittlement, ion bombardment experiments are widely used as a surrogate for neutron irradiation. While avoiding the induced activity, typical for neutron-irradiated samples, is a clear benefit of the ion implantation, the shallow near-surface region of the modified materials may be a complication to the post-irradiation examination (PIE). However, microstructural defects induced by ion implantation can be effectively investigated using various spectroscopic techniques, including slow-positron beam spectroscopy. This method, typically represented by techniques of positron annihilation lifetime spectroscopy and Doppler broadening spectroscopy, enables a unique depth-profile characterisation of the near-surface region affected by ion bombardment or corrosion degradation. One of the best slow-positron beam facilities is available at the pulsed low-energy positron system (PLEPS), operated at FRM-II reactor in Munich (Germany). Bulk studies (such as high energy ion implantation or neutron irradiation experiments) can be, on the other hand, effectively performed using radioisotope positron sources. In this paper, we outline some basics of the two approaches and provide some recommendations to improve the validity of the positron annihilation spectroscopy (PAS) data obtained on ion-irradiated samples using a conventional 22Na positron source.
Effects of Primarily Solidified Dendrite and Thermal Treatments on the M23C6 Precipitation Behavior of High-Chromium White Iron
Authors: Song Young-Gy , Oh Jun-Seok , Choi Baig-Gyu , Jo Chang-Yong , Lee Je-Hyun
Published: October 2021

The precipitation behavior of M23C6 carbide during thermal treatment of high-Cr white iron with various fractions of primarily solidified dendrite was studied and reviewed. M23C6 precipitation in the primarily solidified dendrite occurred preferentially during conventional heat treatment, whereas it occurred scarcely in the eutectic austenite. The reaction between M7C3 and austenite caused the dissolution of M7C3 into austenite, followed by precipitation of M23C6 along the periphery of eutectic M7C3. Relatively low-temperature thermal treatment (modified heat treatment) led to precipitation of M23C6 particles in the eutectic austenite, which is presumed to be caused by solubility difference depending on temperature.
Wear Analysis of an Advanced Al–Al2O3 Composite Infiltrated with a Tin-Based Alloy
Authors: Kolev Mihail , Drenchev Ludmil , Petkov Veselin
Published: October 2021

In this study, a hybrid material is produced, and the effect of different loads varying from 40 to 60 N against an EN-31 steel counter disk on its wear behavior under dry sliding conditions at room temperature is studied. The tribological behavior is studied via the pin-on-disk method and analyzed using primary wear parameters, such as the coefficient of friction (COF), mass wear, and specific wear rate. The obtained results are compared with the results for B83 babbitt under the same wear test conditions. Microstructural observation with scanning electron microscopy (SEM) is performed along with X-ray energy dispersive spectroscopy (EDX) for chemical analysis conduction. The results from the wear experiments indicate that the hybrid material possesses a lower COF, mass wear, and specific wear rate as well as a higher wear resistance in comparison to the B83 babbitt specimen when subjected to the same test conditions. The results from the wear experiments indicate that by applying different loads of 40, 50, and 60 N, the hybrid material possesses a lower mass wear, specific wear rate, and COF specifically at a load of 40 N in comparison to the B83 babbitt specimen under the same test conditions. It was also observed that by increasing the load under dry sliding friction, the hybrid material increases its mass wear and specific wear rate.
Denitrification of Permeable Sand Sediment in a Headwater River Is Mainly Influenced by Water Chemistry, Rather Than Sediment Particle Size and Heterogeneity
Authors: Wang Weibo , Wang Xu , Shu Xiao , Wang Baoru , Li Hongran , Zhang Quanfa
Published: October 2021

Sediment particle size and heterogeneity play an important role in sediment denitrification through direct and indirect effects on, for example, the material exchange rate, environmental gradients, microbial biomass, and grazing pressure. However, these effects have mostly been observed in impermeable sediments. On the other hand, the material exchange of permeable sediments is dominated by advection instead of diffusion, with the exchange or transport rates exceeding those of diffusion by two orders of magnitude relative to impermeable sediments. The impact of permeable sediment particle size and heterogeneity on denitrification remains poorly understood, especially at the millimeter scale. Here, we conducted an in situ control experiment in which we sorted sand sediment into four homogeneous-particle-sizes treatments and four heterogeneous treatments. Each treatment was deployed, in replicate, within the riffle in three different river reaches with contrasting physicochemical characteristics. After incubating for three months, sediment denitrifier communities (nirS, nirK, nosZ), denitrification gene abundances (nirS, nirK, nosZ), and denitrification rates in all treatments were measured. We found that most of the denitrifying microbes in permeable sediments were unclassified denitrifying microbes, and particle size and heterogeneity were not significantly correlated with the functional gene abundances or denitrification rates. Water chemistry was the key controlling factor for the denitrification of permeable sediments. Water NO3−-N directly regulated the denitrification rate of permeable sediments, instead of indirectly regulating the denitrification rate of sediments by affecting the chemical characteristics of the sediments. Our study fills a knowledge gap of denitrification in permeable sediment in a headwater river and highlights that particle size and heterogeneity are less important for permeable sediment denitrification.
Insights into the Bacterial and Nitric Oxide-Induced Salt Tolerance in Sugarcane and Their Growth-Promoting Abilities
Authors: Sharma Anjney , Singh Rajesh Kumar , Singh Pratiksha , Vaishnav Anukool , Guo Dao-Jun , Verma Krishan K. , Li Dong-Ping , Song Xiu-Peng , Malviya Mukesh Kumar , Khan Naeem , Lakshmanan Prakash , Li Yang-Rui
Published: October 2021

Soil salinity causes severe environmental stress that affects agriculture production and food security throughout the world. Salt-tolerant plant-growth-promoting rhizobacteria (PGPR) and nitric oxide (NO), a distinctive signaling molecule, can synergistically assist in the alleviation of abiotic stresses and plant growth promotion, but the mechanism by which this happens is still not well known. In the present study, in a potential salt-tolerant rhizobacteria strain, ASN-1, growth up to 15% NaCl concentration was achieved with sugarcane rhizosphere soil. Based on 16S-rRNA gene sequencing analysis, the strain ASN-1 was identified as a Bacillus xiamenensis. Strain ASN-1 exhibits multiple plant-growth-promoting attributes, such as the production of indole-3-acetic acid, 1-aminocyclopropane-1-carboxylate deaminase, siderophores, HCN, ammonia, and exopolysaccharides as well as solubilized phosphate solubilization. Biofilm formation showed that NO enhanced the biofilm and root colonization capacity of the PGPR strain ASN-1 with host plants, evidenced by scanning electron microscopy. The greenhouse study showed that, among the different treatments, the combined application of PGPR and sodium nitroprusside (SNP) as an NO donor significantly (p ≤ 0.05) enhanced sugarcane plant growth by maintaining the relative water content, electrolyte leakage, gas exchange parameters, osmolytes, and Na+/K+ ratio. Furthermore, PGPR and SNP fertilization reduced the salinity-induced oxidative stress in plants by modulating the antioxidant enzyme activities and stress-related gene expression. Thus, it is believed that the acquisition of advanced information about the synergistic effect of salt-tolerant PGPR and NO fertilization will reduce the use of harmful chemicals and aid in eco-friendly sustainable agricultural production under salt stress conditions.
Pb-Pb and U-Pb Dating of Cassiterite by In Situ LA-ICPMS: Examples Spanning ~1.85 Ga to ~100 Ma in Russia and Implications for Dating Proterozoic to Phanerozoic Tin Deposits
Authors: Neymark Leonid A. , Larin Anatoly M. , Moscati Richard J.
Published: October 2021

This paper investigates applicability of cassiterite to dating ore deposits in a wide age range. We report in situ LA-ICPMS U-Pb and Pb-Pb dating results (n = 15) of cassiterite from six ore deposits in Russia ranging in age from ~1.85 Ga to 93 Ma. The two oldest deposits dated at ~1.83–1.86 Ga are rare metal Vishnyakovskoe located in the East Sayan pegmatite belt and tin deposits within the Tuyukan ore region in the Baikal folded region. Rare metal skarn deposits of Pitkäranta ore field in the Ladoga region, Fennoscandian Shield are dated at ~1.54 Ga. Cassiterite from the Mokhovoe porphyry tin deposit located in western Transbaikalia is 810 ± 20 Ma. The youngest cassiterite was dated from the deposits Valkumei (Russian North East, 108 ± 2 Ma) and Merek (Russian Far East, 93 ± 2 Ma). Three methods of age calculations, including 208Pb/206Pb-207Pb/206Pb inverse isochron age, Tera-Wasserburg Concordia lower intercept age, and 207Pb-corrected 206Pb*/238U age were used and the comparison of the results is discussed. In all cases, the dated cassiterite from the ore deposits agreed, within error, with the established period of magmatism of the associated granitic rock.
Importance of Spatial Autocorrelation in Machine Learning Modeling of Polymetallic Nodules, Model Uncertainty and Transferability at Local Scale
Authors: Gazis Iason-Zois , Greinert Jens
Published: October 2021

Machine learning spatial modeling is used for mapping the distribution of deep-sea polymetallic nodules (PMN). However, the presence and influence of spatial autocorrelation (SAC) have not been extensively studied. SAC can provide information regarding the variable selection before modeling, and it results in erroneous validation performance when ignored. ML models are also problematic when applied in areas far away from the initial training locations, especially if the (new) area to be predicted covers another feature space. Here, we study the spatial distribution of PMN in a geomorphologically heterogeneous area of the Peru Basin, where SAC of PMN exists. The local Moran’s I analysis showed that there are areas with a significantly higher or lower number of PMN, associated with different backscatter values, aspect orientation, and seafloor geomorphological characteristics. A quantile regression forests (QRF) model is used using three cross-validation (CV) techniques (random-, spatial-, and cluster-blocking). We used the recently proposed “Area of Applicability” method to quantify the geographical areas where feature space extrapolation occurs. The results show that QRF predicts well in morphologically similar areas, with spatial block cross-validation being the least unbiased method. Conversely, random-CV overestimates the prediction performance. Under new conditions, the model transferability is reduced even on local scales, highlighting the need for spatial model-based dissimilarity analysis and transferability assessment in new areas.
Genesis of Megacrystalline Uraninite: A Case Study of the Haita Area of the Western Margin of the Yangtze Block, China
Authors: Xu Zhengqi , Yin Minghui , Chen Youliang , Xiang Lu , Song Hao , Zhang Chengjiang , Yao Jian , Guo Hu
Published: October 2021

Megacrystalline uraninite (up to one centimeter in size) represents one of the most important discoveries in uranium mineralogy in the western margin of the Yangtze Block and even in China in recent years. However, the genesis of megacrystalline uraninite remains controversial. In this study, the megacrystalline uraninite found in the felsic and quartz veins in the Haita area is examined for the first time. The study examined the geochemical characteristics of uraninite in the two veins and resulted in two primary findings. (1) The genesis of the uraninite was likely intrusive and was closely related to partial melting. (2) The quartz vein and feldspar vein are cogenetic and have a simple differentiation evolution relationship. Therefore, the partial melting of felsic materials during migmatization may be the most important mechanism of uranium mineralization in the study area. Furthermore, further simple fractional crystallization may be another important mechanism for the formation of megacrystalline uraninite. This study enriches the REE database of uraninite in uranium deposits worldwide, which is meaningful for studying the genesis of megacrystalline uraninite.