bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of Positively Charged Oligopeptides with Blood Plasma Proteins
Authors: Kotynia Aleksandra , Marciniak Aleksandra , Kamysz Wojciech , Neubauer Damian , Krzyżak Edward
Published: February 2023

In this project, we combine two areas of research, experimental characterization and molecular docking studies of the interaction of positively charged oligopeptides with crucial blood plasma proteins. The investigated peptides are rich in NH2 groups of amino acid side chains from Dap, Orn, Lys, and Arg residues, which are relevant in protein interaction. The peptides are 9- and 11-mer with the following sequences: (Lys-Dab-Dab-Gly-Orn-Pro-His-Lys-Arg-Lys-Dbt), (Lys-Dab-Ala-Gly-Orn-Pro-His-Lys-Arg), and (Lys-Dab-Dab-Gly-Orn-Pro-Phe(2-F)-Lys-Arg). The net charge of the compound strongly depends on the pH environment and it is an important aspect of protein binding. The studied oligopeptides exhibit therapeutic properties: anti-inflammatory activity and the capacity to diminish reactive oxygen species (ROS). Therefore, the mechanism of potential binding with blood plasma components is the next challenge. The binding interaction has been investigated under pseudo-physiological conditions with the main blood plasma proteins: albumin (BSA), α1-acid glycoprotein (AAG), and γ-globulin fraction (GGF). The biomolecular quenching constant (kq) and binding constant (Kb) were obtained by fluorescence spectroscopy at various temperatures. Simultaneously, the changes in the secondary structure of proteins were monitored by circular dichroism (CD) and infrared spectroscopy (IR) by quantity analysis. Moreover, molecular docking studies were conducted to estimate the binding affinity, the binding domain, and the chemical nature of these interactions. The results show that the investigated oligopeptides could be mainly transported by albumin, and the binding domain I is the most favored cavity. The BSA and GGF are able to form stable complexes with the studied compounds as opposed to AAG. The binding reactions are spontaneous processes. The highest binding constants were determined for Lys-Dab-Dab-Gly-Orn-Pro-His-Lys-Arg-Lys-Dbt peptide, in which the values of the binding constants Kb to BSA and GGF were 10.1 × 104 dm3mol−1 and 3.39 × 103 dm3mol−1, respectively. The positively charged surface of peptides participated in salt bridge interaction with proteins; however, hydrogen bonds were also formed. The secondary structure of BSA and GGF after contact with peptides was changed. A reduction in the α-helix structure was observed with an increase in the β-sheet and β-turn and random coil structures.
Prolactin in Pregnancies Affected by Pre-Existing Maternal Metabolic Conditions: A Systematic Review
Authors: Rassie Kate , Giri Rinky , Joham Anju E. , Teede Helena , Mousa Aya
Published: February 2023

Women affected by maternal pregestational diabetes mellitus (type 1 or type 2) or by polycystic ovary syndrome experience an increased risk of pregnancy complications, as well as suboptimal lactation outcomes. The hormone prolactin plays important roles in pregnancy and postpartum, both as a metabolic and lactogenic hormone. We aimed to explore, through a systematic review, the relationship between pregestational maternal metabolic conditions and prolactin levels in pregnancy and postpartum. MEDLINE via OVID, CINAHL Plus, and Embase were searched from inception to 9 May 2022. Eligible studies included women who were pregnant or up to 12 months postpartum and had a pre-existing diagnosis of type 1 or type 2 diabetes mellitus or polycystic ovary syndrome; with reporting of at least one endogenous maternal serum prolactin level during this time. Two independent reviewers extracted the data. Eleven studies met the eligibility criteria. The studies were too diverse and heterogeneous to enable meta-analysis. Overall, prolactin levels appeared to be lower in pregnancies affected by type 1 diabetes mellitus. There was little data in polycystic ovary syndrome or type 2 diabetes pregnancy, but prolactin increment across pregnancy in polycystic ovary syndrome emerged as an area for future study. During postpartum, lactation difficulties in women with metabolic disease present before pregnancy are well-described, but the relationship to prolactin remains unclear. Overall, preliminary evidence suggests that pre-existing maternal metabolic disease may alter prolactin dynamics in pregnancy and postpartum. Further well-designed studies in modern cohorts, with standardised collection and serial sampling across pregnancy and postpartum, are required to clarify these associations.
Macrophage Repolarization as a Therapeutic Strategy for Osteosarcoma
Authors: Anand Namrata , Peh Keng Hee , Kolesar Jill M.
Published: February 2023

Macrophages are versatile immune cells and can adapt to both external stimuli and their surrounding environment. Macrophages are categorized into two major categories; M1 macrophages release pro-inflammatory cytokines and produce protective responses that lead to antimicrobial or antitumor activity. M2 or tumor-associated macrophages (TAM) release anti-inflammatory cytokines that support tumor growth, invasion capacity, and metastatic potential. Since macrophages can be re-polarized from an M2 to an M1 phenotype with a variety of strategies, this has emerged as an innovative anti-cancer approach. Osteosarcoma (OS) is a kind of bone cancer and consists of a complex niche, and immunotherapy is not very effective. Therefore, immediate attention to new strategies is required. We incorporated the recent studies that have used M2-M1 repolarization strategies in the aspect of treating OS cancer.
Photoremoval of Bisphenol A Using Hierarchical Zeolites and Diatom Biosilica
Authors: Chudzińska Jagoda , Woźniak Bartosz , Sprynskyy Myroslav , Nowak Izabela , Feliczak-Guzik Agnieszka
Published: February 2023

Bisphenol A (4,4-isopropylidenediphenol, BPA) is an organic compound widely used, e.g., in the production of epoxy resins, plastics, and thermal receipt papers. Unfortunately, bisphenol A has negative effects on human health, which has prompted the search for an effective method of its removal. One of the most promising methods of its elimination is photocatalytic removal. The aim of this study was to design an effective method for the photocatalytic removal of bisphenol A using, for the first time, hierarchical zeolites and ruthenium ion-modified diatom biosilica, and silver as photocatalysts and optimization of the reaction conditions: temperature, pH, and composition of the reaction mixture as well as the electromagnetic wavelength. Additionally, for the first time, the electromagnetic wavelength that would be most suitable for the study was selected. All materials used were initially characterized by XRD and low-temperature nitrogen adsorption/desorption isotherms. Ruthenium ion-modified biosilica proved to be the most effective catalyst for bisphenol A removal, which occurred at a rate higher than 99%.
Machine Learning Modelling for Compressive Strength Prediction of Superplasticizer-Based Concrete
Authors: Sadegh-Zadeh Seyed-Ali , Dastmard Arman , Montazeri Kafshgarkolaei Leili , Movahedi Sajad , Shiry Ghidary Saeed , Najafi Amirreza , Saadat Mozafar
Published: February 2023

Superplasticizers (SPs), also known as naturally high-water reducers, are substances used to create high-strength concrete. Due to the system’s complexity, predicting concrete’s compressive strength can be difficult. In this study, a prediction model for the compressive strength with SP was developed to handle the high-dimensional complex non-linear relationship between the mixing design of SP and the compressive strength of concrete. After performing a statistical analysis of the dataset, a correlation analysis was performed and then 16 supervised machine learning regression techniques were used. Finally, by using the Extra Trees method and creating the SP variable values, it was shown that the compressive strength values of concrete increased with the addition of SP in the optimal dose. The results indicate that superplasticizers can often reduce the water content of concrete by 25 to 35 per cent and consequently resistivity increased by 50 to 75 per cent and the optimum amount of superplasticizers was up to 12 kg per cubic meter as well. From one point, the increase in superplasticizers does not lead to a rise in the concrete compressive strength, and it remains constant. According to the findings, SP additive has the most impact on concrete’s compressive strength after cement. Given the scant information now available on concrete-including superplasticizer, it is prudent to design a concrete mixing plan for future studies. It is also conceivable to investigate how concrete’s compressive strength is impacted by water reduction.
Synthesis of Novel Multifunctional bora-Ibuprofen Derivatives
Authors: Abeysinghe Randika T. , Ravenscroft Alexis C. , Knowlden Steven W. , Akhmedov Novruz G. , Dolinar Brian S. , Popp Brian V.
Published: February 2023

A unique class of β-boron-functionalized non-steroidal anti-inflammatory compound (pinB-NSAID) was previously synthesized via copper-catalyzed 1,2-difunctionalization of the respective vinyl arene with CO2 and B2pin2 reagents. Here, pinacolylboron-functionalized ibuprofen (pinB-ibuprofen) was used as a model substrate to develop the conditions for pinacol deprotection and subsequent boron functionalization. Initial pinacol-boronic ester deprotection was achieved by transesterification with diethanolamine (DEA) from the boralactonate organic salt. The resulting DEA boronate adopts a spirocyclic boralactonate structure rather than a diazaborocane–DABO boronate structure. The subsequent acid-mediated hydrolysis of DEA and transesterification/transamination provided a diverse scope of new boron-containing ibuprofen derivatives.
Survival Outcome of Gastric Signet Ring Cell Carcinoma Based on the Optimal Number of Examined Lymph Nodes: A Nomogram- and Machine-Learning-Based Approach
Authors: Lai Yongkang , Xie Junfeng , Yin Xiaojing , Lai Weiguo , Tang Jianhua , Du Yiqi , Li Zhaoshen
Published: February 2023

The optimal number of examined lymph nodes (ELNs) for gastric signet ring cell carcinoma recommended by National Comprehensive Cancer Network guidelines remains unclear. This study aimed to determine the optimal number of ELNs and investigate its prognostic significance. In this study, we included 1723 patients diagnosed with gastric signet ring cell carcinoma in the Surveillance, Epidemiology, and End Results database. X-tile software was used to calculate the cutoff value of ELNs, and the optimal number of ELNs was found to be 32 for adequate nodal staging. In addition, we performed propensity score matching (PSM) analysis to compare the 1-, 3-, and 5-year survival rates; 1-, 3-, and 5-year survival rates for total examined lymph nodes (ELNs < 32 vs. ELNs ≥ 32) were 71.7% vs. 80.1% (p = 0.008), 41.8% vs. 51.2% (p = 0.009), and 27% vs. 30.2% (p = 0.032), respectively. Furthermore, a predictive model based on 32 ELNs was developed and displayed as a nomogram. The model showed good predictive ability performance, and machine learning validated the importance of the optimal number of ELNs in predicting prognosis.
Influence of Prostate Cancer on Thulium Vapoenucleation of the Prostate—A Multicentre Analysis
Authors: Lamersdorf Tobias , Netsch Christopher , Becker Benedikt , Wülfing Christian , Anheuser Petra , Engel Oliver , Gross Andreas , Rosenbaum Clemens
Published: February 2023

Purpose: Prostate cancer (PCa) and benign prostatic hyperplasia (BPH) are common in elderly men. Data on the laser-based surgery known as thulium vapoenucleation of the prostate (ThuVEP) in PCa patients are rare. Our objective was to analyse the feasibility, safety and functional outcome of ThuVEP in patients with lower urinary tract symptoms (LUTS) and PCa. Methods: Multicentre study, including 1256 men who underwent ThuVEP for LUTS. Maximum urinary flow rate (Qmax) and post-void residual volume (PVR) were measured perioperatively. The International Prostate Symptome Score (IPSS) was measured perioperatively and at follow-up (FU). Perioperative complications were captured. Reoperation rate was captured at FU. Results: Of 994 men with complete data, 286 (28.8%) patients had PCa. The most common Gleason score was 3 + 3 in 142 patients (49.7%). Most common was low-risk PCa (141 pts; 49.3%). PCa patients were older, had smaller prostates and had higher prostate-specific antigen (PSA) values (all p < 0.001). Comparing non-PCa and PCa patients, no differences occurred perioperatively. IPSS, quality of life and PVR decreased (all p < 0.001) and Qmax improved (p < 0.001) in both groups. Reoperation rates did not differ. The results of low- vs. intermediate-/high-risk PCa patients were comparable. Conclusion: ThuVEP is a safe and long-lasting treatment option for patients with LUTS with or without PCa. No differences occurred when comparing low- to intermediate-/high-risk PCa patients.
Actigraphic Sensors Describe Stroke Severity in the Acute Phase: Implementing Multi-Parametric Monitoring in Stroke Unit
Authors: Reale Giuseppe , Iacovelli Chiara , Rabuffetti Marco , Manganotti Paolo , Marinelli Lucio , Sacco Simona , Furlanis Giovanni , Ajčević Miloš , Zauli Aurelia , Moci Marco , Giovannini Silvia , Crosetti Simona , Grazzini Matteo , Castiglia Stefano Filippo , Podestà Matteo , Calabresi Paolo , Ferrarin Maurizio , Caliandro Pietro
Published: February 2023

Actigraphy is a tool used to describe limb motor activity. Some actigraphic parameters, namely Motor Activity (MA) and Asymmetry Index (AR), correlate with stroke severity. However, a long-lasting actigraphic monitoring was never performed previously. We hypothesized that MA and AR can describe different clinical conditions during the evolution of the acute phase of stroke. We conducted a multicenter study and enrolled 69 stroke patients. NIHSS was assessed every hour and upper limbs’ motor activity was continuously recorded. We calculated MA and AR in the first hour after admission, after a significant clinical change (NIHSS ± 4) or at discharge. In a control group of 17 subjects, we calculated MA and AR normative values. We defined the best model to predict clinical status with multiple linear regression and identified actigraphic cut-off values to discriminate minor from major stroke (NIHSS ≥ 5) and NIHSS 5–9 from NIHSS ≥ 10. The AR cut-off value to discriminate between minor and major stroke (namely NIHSS ≥ 5) is 27% (sensitivity = 83%, specificity = 76% (AUC 0.86 p < 0.001), PPV = 89%, NPV = 42%). However, the combination of AR and MA of the non-paretic arm is the best model to predict NIHSS score (R2: 0.482, F: 54.13), discriminating minor from major stroke (sensitivity = 89%, specificity = 82%, PPV = 92%, NPV = 75%). The AR cut-off value of 53% identifies very severe stroke patients (NIHSS ≥ 10) (sensitivity = 82%, specificity = 74% (AUC 0.86 p < 0.001), PPV = 73%, NPV = 82%). Actigraphic parameters can reliably describe the overall severity of stroke patients with motor symptoms, supporting the addition of a wearable actigraphic system to the multi-parametric monitoring in stroke units.
Cardiac Contractility Modulation Therapy in Patients with Amyloid Cardiomyopathy and Heart Failure, Case Report, Review of the Biophysics of CCM Function, and AMY-CCM Registry Presentation
Authors: Marchese Procolo , Gennaro Francesca , Mazzotta Giovanni , Acciarri Claudia , Amabili Stenio , Bonanni Carlo , D’Antonio Antonella , Delfino Domenico , Di Vito Luca , Partemi Manrico , Pascucci Riccardo , Romandini Andrea , Scalone Giancarla , Silenzi Simona , Grossi Pierfrancesco
Published: February 2023

Cardiac amyloidosis may result in an aggressive form of heart failure (HF). Cardiac contractility modulation (CCM) has been shown to be a concrete therapeutic option in patients with symptomatic HF, but there is no evidence of its application in patients with cardiac amyloidosis. We present the case of TTR amyloidosis, where CCM therapy proved to be effective. The patient had a history of multiple HF hospitalizations due to an established diagnosis of wild type TTR-Amyloidosis with significant cardiac involvement. Since he was highly symptomatic, except during continuous dobutamine and diuretic infusion, it was opted to pursue CCM therapy device implantation. At follow up, a significant improvement in clinical status was reported with an increase of EF, functional status (6 min walk test improved from zero meters at baseline, to 270 m at 1 month and to 460 m at 12 months), and a reduction in pulmonary pressures. One year after device implantation, no other HF hospital admission was needed. CCM therapy may be effective in this difficult clinical setting. The AMY-CCM Registry, which has just begun, will evaluate the efficacy of CCM in patients with HF and diagnosed TTR amyloidosis to bring new evidence on its potential impact as a therapeutic option.
Clinical Distribution and Drug Resistance of Pseudomonas aeruginosa in Guangzhou, China from 2017 to 2021
Authors: Lyu Jingwen , Chen Huimin , Bao Jinwei , Liu Suling , Chen Yiling , Cui Xuxia , Guo Caixia , Gu Bing , Li Lu
Published: February 2023

The aim of the current study was to analyse the distribution of antimicrobial drug resistance (AMR) among Pseudomonas aeruginosa (P. aeruginosa, PA) isolates from Guangdong Provincial People’s Hospital (GDPH) from 2017 to 2021, and the impact of the COVID-19 outbreak on changes in the clinical distribution and drug resistance rate of P. aeruginosa to establish guidelines for empiric therapy. Electronic clinical data registry records from 2017 to 2021 were retrospectively analysed to study the AMR among P. aeruginosa strains from GDPH. The strains were identified by VITEK 2 Compact and MALDI-TOF MS, MIC method or Kirby–Bauer method for antibiotic susceptibility testing. The results were interpreted according to the CLSI 2020 standard, and the data were analysed using WHONET 5.6 and SPSS 23.0 software. A total of 3036 P. aeruginosa strains were detected in the hospital from 2017 to 2021, and they were primarily distributed in the ICU (n = 1207, 39.8%). The most frequent specimens were respiratory tract samples (59.6%). The detection rate for P. aeruginosa in 5 years was highest in September, and the population distribution was primarily male(68.2%). For the trend in the drug resistance rate, the 5-year drug resistance rate of imipenem (22.4%), aztreonam (21.5%) and meropenem (19.3%) remained at high levels. The resistance rate of cefepime decreased from 9.4% to 4.8%, showing a decreasing trend year by year (p < 0.001). The antibiotics with low resistance rates were aminoglycoside antibiotics, which were gentamicin (4.4%), tobramycin (4.3%), and amikacin (1.4%), but amikacin showed an increasing trend year by year (p = 0.008). Our analysis indicated that the detection rate of clinically resistant P. aeruginosa strains showed an upwards trend, and the number of multidrug-resistant (MDR) strains increased year by year, which will lead to stronger pathogenicity and mortality. However, after the outbreak of COVID-19 in 2020, the growth trend in the number of MDR bacteria slowed, presumably due to the strict epidemic prevention and control measures in China. This observation suggests that we should reasonably use antibiotics and treatment programs in the prevention and control of P. aeruginosa infection. Additionally, health prevention and control after the outbreak of the COVID-19 epidemic (such as wearing masks, washing hands with disinfectant, etc., which reduced the prevalence of drug resistance) led to a slowdown in the growth of the drug resistance rate of P. aeruginosa in hospitals, effectively reducing the occurrence and development of drug resistance, and saving patient’s treatment costs and time.
Composite Single Lap Shear Joint Integrity Monitoring via Embedded Electromechanical Impedance Sensors
Authors: Caldwell Steven P. , Radford Donald W.
Published: February 2023

Composite bonded structure is a prevalent portion of today’s aircraft structure. Adequate bond integrity is a critical aspect of fabrication and service, especially since many of today’s structural bonds are critical for flight safety. Over the last decade, non-destructive bond evaluation techniques have improved but still cannot detect a structurally weak bond that exhibits full adherend/adhesive contact. The result is that expensive and time-consuming structural proof testing continues to be required to verify bond integrity. The objective of this work is to investigate the feasibility of bondline integrity monitoring using piezoelectric sensors, embedded at different locations within the composite joint, and to assess the benefits of monitoring the thickness mode in addition to the radial mode. Experiments and analyses are performed on single lap shear composite joints, with and without embedded sensors, subjected to incrementally increasing tensile loads. The results indicate that the embedded piezoelectric sensors measure a change in the resonance in both the radial and thickness mode during incremental loading and that the thickness resonance shows enhanced sensitivity to impending failure. Thus, it is demonstrated that monitoring both modes of the piezoelectric sensor provides addition details for prognostic performance evaluation.
The Construct Validity of Intellect and Openness as Distinct Aspects of Personality through Differential Associations with Reaction Time
Authors: Willoughby Emily A. , Kim Yuri , Lee James J. , DeYoung Colin G.
Published: February 2023

The construct validity of group factor models of personality, which are typically derived from factor analysis of questionnaire items, relies on the ability of each factor to predict meaningful and differentiated real-world outcomes. In a sample of 481 participants, we used the Big Five Aspect Scales (BFAS) personality questionnaire, two laboratory-measured reaction time (RT) tasks, and a short-form test of cognitive ability (ICAR-16) to test the hypothesis that the Intellect and Openness aspects of Big Five Openness to Experience differentially correlate with reaction time moments. We found that higher scores on the Intellect aspect significantly correlate with faster and less variable response times, while no such association is observed for the Openness aspect. Further, we found that this advantage lies solely in the decisional, but not perceptual, stage of information processing; no other Big Five aspect showed a similar pattern of results. In sum, these findings represent the largest and most comprehensive study to date on personality factors and reaction time, and the first to demonstrate a mechanistic validation of BFAS Intellect through a differential pattern of associations with RT and Big Five personality aspects.
Energy Autonomous Wireless Sensing Node Working at 5 Lux from a 4 cm2 Solar Cell
Authors: Meli Marcel Louis , Favre Sebastien , Maij Benjamin , Stajic Stefan , Boebel Manuel , Poole Philip John , Schellenberg Martin , Kouzinopoulos Charalampos S.
Published: February 2023

Harvesting energy for IoT nodes in places that are permanently poorly lit is important, as many such places exist in buildings and other locations. The need for energy-autonomous devices working in such environments has so far received little attention. This work reports the design and test results of an energy-autonomous sensor node powered solely by solar cells. The system can cold-start and run in low light conditions (in this case 20 lux and below, using white LEDs as light sources). Four solar cells of 1 cm2 each are used, yielding a total active surface of 4 cm2. The system includes a capacitive sensor that acts as a touch detector, a crystal-accurate real-time clock (RTC), and a Cortex-M3-compatible microcontroller integrating a Bluetooth Low Energy radio (BLE) and the necessary stack for communication. A capacitor of 100 μF is used as energy storage. A low-power comparator monitors the level of the energy storage and powers up the system. The combination of the RTC and touch sensor enables the MCU load to be powered up periodically or using an asynchronous user touch activity. First tests have shown that the system can perform the basic work of cold-starting, sensing, and transmitting frames at +0 dBm, at illuminances as low as 5 lux. Harvesting starts earlier, meaning that the potential for full function below 5 lux is present. The system has also been tested with other light sources. The comparator is a test chip developed for energy harvesting. Other elements are off-the-shelf components. The use of commercially available devices, the reduced number of parts, and the absence of complex storage elements enable a small node to be built in the future, for use in constantly or intermittently poorly lit places.
Biodiesel as Dispersant to Improve the Stability of Asphaltene in Marine Very-Low-Sulfur Fuel Oil
Authors: Zhou Daping , Wei Haijun , Tan Zhiwen , Xue Shuye , Qiu Ye , Wu Shen
Published: February 2023

Since the implementation of the sulfur cap legislation in 2020, marine very-low-sulfur fuel oil, often known as VLSFO, has become a crucial source of fuel for the contemporary shipping industry. However, both the production and utilization processes of VLSFO are plagued by the poor miscibility of the cutter fraction and the residual fraction, which can result in the precipitation of asphaltene. In this study, biodiesel was chosen as a cutter fraction to improve the stability and compatibility of asphaltene in VLSFO because of its environmental benefit and strong solubility. The average chemical structure of asphaltene derived from the marine low-sulfur fuel oil sample was analyzed using element analysis, FTIR, 1HNMR, and time-flight spectroscopy. The composition of biodiesel was analyzed using GC-MS. It was found that the asphaltene had a feature of a short side chain, low H/C ratio, high aromaticity, and a high proportion of heteroatoms. Both laboratory experiments and molecular dynamic simulations were applied to investigate the dispersion effect and mechanism compared with other dispersants. The dispersion effect of biodiesel was studied using measurements of the initial precipitation point (IPP), dispersion improvement rate, and morphology of asphaltene in the model oil. Experimental results revealed that biodiesel was fully compatible with heavy fuel oil and that it can postpone the IPP from 46% to 54% and increase the dispersion improvement rate to 35%. Molecular dynamics (MDs) simulation results show that biodiesel can form strong interactions with the fused aromatics structures and heteroatoms in the asphaltene; such interactions can increase the solubility of asphaltene and acts as a “connection bridge” to promote the dispersion effect of asphaltene molecules.
Effects of Iron Valence on the Growth, Photosynthesis, and Fatty Acid Composition of Phaeodactylum tricornutum
Authors: Wang Haowen , Su Qingling , Zhuang Yanmin , Wu Chengzong , Tong Shanying , Guan Bo , Zhao Yancui , Qiao Hongjin
Published: February 2023

Iron is a limiting factor that controls the phytoplankton biomass of the ocean and plays an important role in the lipid production of microalgae. Elucidating the effects of different iron valences on microalgae is helpful for their commercial production. We investigated the growth, photosynthesis, and fatty acid profile of the model diatom Phaeodactylum tricornutum cultured with depleted Fe, Fe2+, Fe2+/Fe3+, and Fe3+. Samples were taken every 24 h for 8 days, and their cell density, photosynthetic pigment content, chlorophyll fluorescence, total fatty acid content, and fatty acid composition were analyzed. The cell densities of the Fe2+ and Fe2+/Fe3+ groups were significantly higher than those of the control and Fe3+ groups (p < 0.05). They were 1.26 times and 1.23 times higher than those in the Fe-depleted group. The contents of chlorophyll a and c in the Fe2+ group were significantly higher than those in the Fe-depleted group (p < 0.05). The chlorophyll fluorescence results show that Fe2+ enhanced the photosynthesis of P. tricornutum to a greater extent than Fe3+. On the eighth day of harvest, Fv/Fm and Y(II) in the Fe2+ group were 0.672 and 0.476, respectively, being 1.10 and 1.19 times greater than those in the Fe3+ group and 1.15 and 1.33 times greater than those in the Fe-depleted group, respectively. Compared with the control group, the levels of saturated fatty acids of the Fe2+/Fe3+ and Fe3+ groups were significantly higher (p < 0.05) at 21.36 ± 1.24% and 21.20 ± 0.13%, respectively. The levels of polyunsaturated fatty acids of the Fe2+/Fe3+ group were significantly lower (p < 0.05) at 29.82 ± 2.75%. Our results show that P. tricornutum exhibited physiological plasticity, including changes in photosynthetic activities and shifts in fatty acid composition, in response to different iron valences and that Fe2+ was more beneficial to the biomass production of this species than Fe3+. These findings are applicable to the production of biomass and polyunsaturated fatty acids.
Beta Diversity of Arbuscular Mycorrhizal Communities Increases in Time after Crop Establishment of Peruvian Sacha Inchi (Plukenetia volubilis)
Authors: de la Sota Ricaldi Ana Maria , Rengifo del Águila Sofía , Blas Sevillano Raúl , López-García Álvaro , Corazon-Guivin Mike Anderson
Published: February 2023

(1) Background: Beta diversity, i.e., the variance in species compositions across communities, has been pointed out as a main factor for explaining ecosystem functioning. However, few studies have directly tested the effect of crop establishment on beta diversity. We studied beta diversity patterns of arbuscular mycorrhizal (AM) fungal communities associated to sacha inchi (Plukenetia volubilis) after crop establishment. (2) Methods: We molecularly characterized the AM fungal communities associated to roots of sacha inchi in plots after different times of crop establishment, from less than one year to older than three. We analyzed the patterns of alpha, beta, and phylogenetic diversity, and the sources of variation of AM fungal community composition. (3) Results: Beta diversity increased in the older plots, but no temporal effect in alpha or phylogenetic diversity was found. The AM fungal community composition was driven by environmental factors (altitude and soil conditions). A part of this variation could be attributed to differences between sampled locations (expressed as geographic coordinates). Crop age, in turn, affected the composition with no interactions with the environmental conditions or spatial location. (4) Conclusions: These results point out towards a certain recovery of the soil microbiota after sacha inchi establishment. This fact could be attributed to the low-impact management associated to this tropical crop.
What Can District Migration Rates Tell Us about London’s Functional Urban Area?
Authors: Gray David
Published: February 2023

In the early 1990s, Anthony Fielding coined the term ‘escalator region’ to describe how London and the South East attracted those with greater human capital by offering them superior career prospects and enhanced returns in the housing markets. When delineating a housing or labour market area, it is not uncommon to require high levels of migration and commuting within the market area relative to those that cross the area’s boundaries. Net migration flows to and from this escalator region change depending on the age range one examines, making migration across boundaries relatively high. It is proposed that focusing on age ranges that reflect younger adults would capture the extent of the market. In particular, the birth of a first child is likely to trigger migration, but that movement is constrained to be within the boundary of the market area. The decision to buy a dwelling would be made around the time of this event. This paper delineates market areas using spatial autocorrelation. This has the advantage of using a statistical criterion rather than a containment value. Broadly similar areas in the Greater South East are revealed using relative housing affordability measures, the movement of infants and the migration of 20- to 24-year-olds. It is argued that the time-varying patterns of migration of 30- to 39-year-olds is reflective of a change in housing affordability, forcing more households to migrate with children whilst renting.
Evaluation for Water and Land Resources System Efficiency and Influencing Factors in China: A Two-Stage Network DEA Model
Authors: Liu Cong , Jiang Wenlai , Liu Yang , Liu Yunfei
Published: February 2023

Improving the water and land resource system efficiency can effectively alleviate the severe situation of water and land resources in China. Through the two-stage network DEA model, spatial autocorrelation analysis, multiple linear regression, and geographic weighted regression analysis, this paper revealed the change characteristics, distribution types, spatial correlation relationship, and main driving factors of China’s water and land resources system efficiency. The results show that the water and land resources system efficiency fluctuates widely in different regions. Water and land resources systems in nearly half of the provinces belong to the high development, low economic benefit transformation type, mainly distributed in southwestern and northwestern China. The economic benefit transformation is becoming the weak link of water and land resources system. The overall efficiency of water and land resource system has significant spatial positive correlation, and this correlation has an increasing trend. Low-Low Clusters occupy more provinces. The urbanization level, population density, proportion of output value of secondary and tertiary industries, and effective irrigation all have a positive impact on the overall efficiency of water and land resources system. The impact of the proportion of construction land is bidirectional and the per land pesticide application has negative impact in general.
The Influence of Ultrasound on the Growth of Nannochloris sp. in Modified Growth Medium
Authors: Vintila Alin Cristian Nicolae , Vinatoru Mircea , Galan Ana-Maria , Vlaicu Alexandru , Ciltea-Udrescu Mihaela , Paulenco Anca , Gavrila Adina Ionuta , Calinescu Ioan
Published: February 2023

The influence of ultrasound irradiation on the algal biomass productivity as well as its oil content and fatty acids profile, grown in a modified Zarrouk medium, i.e., deproteinized whey waste solution, was investigated. The algal samples (Nannochloris sp. 424-1 microalgae) were grown for 7 days in a thermostated incubator at 28 °C, shaken under continuous light. During this period, the algal biomass was subjected to induced stress by ultrasonic irradiation at different powers and sonication time. The obtained results demonstrate that ultrasound stressing of algae biomass has a positive effect on both the quantity of biomass and the oil obtained, also causing a shift in fatty acid composition by increasing the proportion of C16 and C18 polyunsaturated fatty acids. A low dosage level of exposure to the ultrasound led to algal biomass increase as well as lipid accumulation. For both types of irradiation modes which were investigated, daily and only initial irradiation, the beneficial effect of the ultrasound decreases as the exposure time increases and the excessive sonication becomes detrimental to microalgae growth.
Intelligent Road-Adaptive Semi-Active Suspension and Integrated Cruise Control
Authors: Basargan Hakan , Mihály András , Gáspár Péter , Sename Olivier
Published: February 2023

The availability of road and vehicle data enables the control of road vehicles to adapt for different road irregularities. Vision-based or stored road data inform the vehicle regarding the road ahead and surface conditions. Due to these abilities, the vehicle can be controlled efficiently to deal with different road irregularities in order to improve driving comfort and stability performances. The present paper proposes an integration method for an intelligent, road-adaptive, semi-active suspension control and cruise control system. The road-adaptive, semi-active suspension controller is designed through the linear parameter-varying (LPV) method, and road adaptation is performed with a road adaptivity algorithm that considers road irregularities and vehicle velocity. The road adaptivity algorithm calculates a dedicated scheduling variable that modifies the operating mode of the LPV controller. This modification of operation mode provides a trade-off between driving comfort and vehicle stability performances. Regarding the cruise control, the velocity design of the vehicle is based on the ISO 2631-1 standard, the created database, and the look-ahead road information. For each road irregularity, the velocity of the vehicle is designed according to previous measurements and the table of ISO 2631-1 standard. The comfort level must be selected in order to calculate dedicated velocity for road irregularity. The designed velocity is tracked by the velocity-tracking controller evaluated with the LPV control framework. The designed controllers are integrated, and the operation of the integrated method is validated in a TruckSim simulation environment.
Smartphone-Based Indoor Floor Plan Construction via Acoustic Ranging and Inertial Tracking
Authors: Meng Chuize , Jiang Shan , Wu Mengning , Xiao Xuan , Tao Dan , Gao Ruipeng
Published: February 2023

The lack of indoor floor plans is one of the major obstacles to ubiquitous indoor location-based services. Dedicated mobile robots with high-precision sensors can measure and produce accurate indoor maps, but the deployment remains low for the public. Computer vision techniques are adopted by some existing smartphone-based methods to build the 3D point cloud, which have the cost of a quantity of the efforts of image collection and the risk of privacy issues. In this paper, we propose BatMapper-Plus which adopt acoustic ranging and inertial tracking to construct precise and complete indoor floor plans on smartphones. It emits acoustic signals to measure the distance from the smartphone to a neighbouring wall segment, and produces accessible areas by surrounding the building during walking. It also refines the constructed indoor floor plan to eliminate scattered segments, and identifies connection areas, including stairs and elevators among different floors. In addition, we propose an LSTM-based dead-reckoning model which is trained by outdoor IMU readings and GPS records, and use it to infer the step length during indoor walking, thereby improving the floor plan quality. We also elaborate how to use the constructed map for indoor navigation, i.e., a Dynamic Time Warping algorithm which automatically matches current inertial readings and historical sensory data during map construction to produce fine-grained walking guidance. To show our effectiveness compared with the state-of-the-art, we carry out extensive experiments in a teaching building and a residential building. It proves that our method is efficient without any privacy concerns and texture/illumination limitations.
Bidirectional RRT*-Based Path Planning for Tight Coordination of Dual Redundant Manipulators
Authors: Dai Jun , Zhang Yi , Deng Hua
Published: February 2023

There are closed-chain constraints between the left manipulator and the right manipulator in tight coordination of the dual redundant manipulator. The existing planning algorithms suitable for loose coordination cannot be directly applied to tight coordination, as the planned path cannot satisfy the closed-chain constraints. To solve the above problem, a master-slave planning method based on bidirectional RRT* is proposed for dual redundant manipulators. Bidirectional RRT* is adopted to plan the path of the master manipulator. The path of the slave manipulator is calculated by terminal generalized velocity constraints instead of terminal position and posture constraints. Moreover, a local path replanning strategy is proposed to solve the problem that the planned path is actually not feasible due to the discontinuous joint path of the slave manipulator. The joint self-motion in the null space is utilized to keep the terminal position and posture of the slave manipulator unchanged. The proposed method is verified by simulations and experiments and the results show that it can solve the discontinuity problem, increase the success rate, shorten the planning time and satisfy closed-chain constraints. Therefore, the proposed method can be feasibly and effectively applied to the tight coordination of dual redundant manipulators.
Fault Detection in Aircraft Flight Control Actuators Using Support Vector Machines
Authors: Grehan Julianne , Ignatyev Dmitry , Zolotas Argyrios
Published: February 2023

Future generations of flight control systems, such as those for unmanned autonomous vehicles (UAVs), are likely to be more adaptive and intelligent to cope with the extra safety and reliability requirements due to pilotless operations. An efficient fault detection and isolation (FDI) system is paramount and should be capable of monitoring the health status of an aircraft. Historically, hardware redundancy techniques have been used to detect faults. However, duplicating the actuators in an UAV is not ideal due to the high cost and large mass of additional components. Fortunately, aircraft actuator faults can also be detected using analytical redundancy techniques. In this study, a data-driven algorithm using Support Vector Machine (SVM) is designed. The aircraft actuator fault investigated is the loss-of-effectiveness (LOE) fault. The aim of the fault detection algorithm is to classify the feature vector data into a nominal or faulty class based on the health of the actuator. The results show that the SVM algorithm detects the LOE fault almost instantly, with an average accuracy of 99%.
Failure of Threaded Connections: A Literature Review
Authors: Croccolo Dario , De Agostinis Massimiliano , Fini Stefano , Mele Mattia , Olmi Giorgio , Scapecchi Chiara , Tariq Muhammad Hassaan Bin
Published: February 2023

Threaded fasteners are vastly used in the industry due to ease of mounting and dismounting and flexibility of design. Nonetheless, several researchers indicate that most failures recorded on nearly any kind of machinery and vehicles are initiated at fasteners. This review paper aims at summarising the failures involving threaded fasteners available in the literature. The analysis involves categorization of the failures according to the root cause, e.g., incorrect assembly, overload, fatigue, preload loss during operation, among others. The purpose of this review paper is to give a systematic glance of the topic to the scientific and technical community, to correctly orient future investigations on the broad topic of threaded fasteners.
On Galvanometer Laser Projection Positioning to Layups of Large Composite Material
Authors: Xu Ziqi , Duan Xuechao , Zhu Yue , Zhang Dan
Published: February 2023

A laser projection positioning technique for large composite production based on a scanning galvanometer is proposed in this paper. First, based on the projecting model of the scanning galvanometer, a solution is proposed for the problem which includes pose calculations of the galvanometer projection and autocorrection technology. Then, according to the solution of the perspective-n-point (PNP) problem in the control software for the pose of the scanning galvanometer relative to the projection object, an improved genetic algorithm is proposed to optimize the results of calculating the pose. Meanwhile, to account for the tangential distortion caused by the perturbation between the scanning galvanometer and the projected object during the actual manufacturing process, the projection pattern is corrected by the perspective transform method, thus ensuring the accuracy of the projection. Eventually, in order to evaluate the proposed method, a general scheme of the projection positioning system is designed, and software is developed for the projection device relative to the pose calibration of the composite material mold and projection image correction. Following that, 3D printing model projection experiment and the large composite layup projection positioning tests are conducted with the experimental prototype of the projection positioning system. The result of the 3D printing model projection experiment shows that the calculating accuracy of the relative pose based on the improved adaptive genetic algorithm achieves 0.0007 mm, which is superior to the 1.115 mm accuracy of the solution of photographing the target with the camera. In addition, after a small deformation of the mold in the actual working conditions, the influence of the target localization point in the PNP problem in 2D and 3D coordinates on the algorithm is compared, and the optimized errors are respectively scaled to 2 mm and 0.2 mm. These numerical simulations and experimental results in working conditions show that the proposed method has high accuracy, high robustness, and fast astringency, and it provides a candidate for projection positioning of large composite material layups.
The Squeeze Film Effect with a High-Pressure Boundary in Aerostatic Bearings
Authors: Wu Yangong , Xue Jiadai , Qiao Zheng , Chen Wentao , Wang Bo
Published: February 2023

The squeeze film effect was discussed in several fields, but mostly under the same pressure boundary conditions. However, pressures at the inlet and outlet are different for aerostatic bearings. In this paper, the dynamic Reynolds equation group, with the stiffness and damping pressure written separately, is deducted and numerically solved with a high-pressure boundary for a parallel flat and circular thin film. The circular thin film considers the two results of the supply pressure boundary inside and outside. All dynamic pressure distribution and stiffness curves are given in a dimensionless form, and a comparative analysis of squeeze film characteristics with and without external pressure is conducted. From the calculation results, it can be concluded that the squeeze effect shows damping for zero-frequency and stiffness for infinite-frequency for compressible lubricants. The dynamic pressure in the static high pressure region is also high at high frequencies affected by gas compressibility. Based on these analytical results, the transfer functions of the thin film are given to further analyze the dynamic performance of aerostatic bearings, and the shape of the response curve approximates an exponential decay form, even when the amplitude increases to 10% of the gas film thickness.
Controllability of Semilinear Stochastic Generalized Systems in Hilbert Spaces by GE-Evolution Operator Method
Authors: Ge Zhaoqiang
Published: February 2023

Controllability is a basic problem in the study of stochastic generalized systems. Compared with ordinary stochastic systems, the structure of stochastic singular systems is more complex, and it is necessary to study the controllability of stochastic generalized systems in the context of different solutions. In this paper, the controllability of semilinear stochastic generalized systems was investigated by using a GE-evolution operator for integral and impulsive solutions in Hilbert spaces. Some sufficient and necessary conditions were obtained. Firstly, the existence and uniqueness of the integral solution of semilinear stochastic generalized systems were discussed using the GE-evolution operator theory and Banach fixed point theorem. The existence and uniqueness theorem of the integral solution was obtained. Secondly, the approximate controllability of semilinear stochastic generalized systems was studied in the case of the integral solution. Thirdly, the existence and uniqueness of the impulsive solution of semilinear stochastic generalized systems were considered, and some sufficient conditions were provided. Fourthly, the approximate controllability of semilinear stochastic generalized systems was studied for the impulsive solution. At last, the exact controllability of linear stochastic systems was studied in the case of the impulsive solution, with some necessary and sufficient conditions given. The obtained results have important theoretical and practical value for the study of controllability of semilinear stochastic generalized systems.