bluuebunny/crossref_metadata_2025 huggingface dataset:
Processing methods for conductive polymer composite bipolar plates: Effect on plate quality and performance
Authors: Alo Oluwaseun Ayotunde , Otunniyi Iyiola Olatunji , Sadiku Emmanuel Rotimi
Published: January 2023

Conductive polymer composites (CPCs) have been identified as viable replacements for graphite and metals for polymer electrolyte membrane fuel cell (PEMFC) bipolar plates (BPs). One important factor, apart from composite formulation, that affects the quality and properties of CPC BPs is the processing route. Therefore, understanding the possible processing methods for different matrix–filler combinations and their effects on the quality and properties of the plates can help in controlling and improving the final performance of BPs. This paper reviews the blending and molding techniques for CPC BPs, with a focus on relationship between formulation and processing method. The effects of processing route and conditions on microstructural features of CPC BPs, which affect the performance of the plates are also discussed. Finally, directions for further studies with potential to advance the development of quality and high‐performance CPC BPs are highlighted. Identified key areas for further research include control of filler orientation to improve through‐plane conductivity, correlation between processing parameters and dimensional accuracy of molded plates, and additive manufacturing of composite BPs.
Identification of a novel gene signature for neuroblastoma differentiation using a Boolean implication network
Authors: Zage Peter E. , Huo Yuchen , Subramonian Divya , Le Clorennec Christophe , Ghosh Pradipta , Sahoo Debashis
Published: January 2023

Although induction of differentiation represents an effective strategy for neuroblastoma treatment, the mechanisms underlying neuroblastoma differentiation are poorly understood. We generated a computational model of neuroblastoma differentiation consisting of interconnected gene clusters identified based on symmetric and asymmetric gene expression relationships. We identified a differentiation signature consisting of series of gene clusters comprised of 1251 independent genes that predicted neuroblastoma differentiation in independent datasets and in neuroblastoma cell lines treated with agents known to induce differentiation. This differentiation signature was associated with patient outcomes in multiple independent patient cohorts and validated the role of MYCN expression as a marker of neuroblastoma differentiation. Our results further identified novel genes associated with MYCN via asymmetric Boolean implication relationships that would not have been identified using symmetric computational approaches and that were associated with both neuroblastoma differentiation and patient outcomes. Our differentiation signature included a cluster of genes involved in intracellular signaling and growth factor receptor trafficking pathways that is strongly associated with neuroblastoma differentiation, and we validated the associations of UBE4B, a gene within this cluster, with neuroblastoma cell and tumor differentiation. Our findings demonstrate that Boolean network analyses of symmetric and asymmetric gene expression relationships can identify novel genes and pathways relevant for neuroblastoma tumor differentiation that could represent potential therapeutic targets.
Maximizing Use of Pelagic Capture Fisheries for Global Protein Supply: Potential and Caveats Associated with Fish and Co‐Product Conversion into Value‐Add Ingredients
Authors: Hayes Maria
Published: January 2023

Globally, capture fisheries contribute significantly to protein supply and the food security of a third of the world's population. Although capture fisheries production has not significantly increased in tonnes landed per annum during the last two decades (since 1990), it still produced a greater tonnage of protein than aquaculture in 2018. Policy in the European Union and other locations favors production of fish through aquaculture to preserve existing fish stocks and prevent extinction of species from overfishing. However, aquaculture production of fish in order to feed the growing global population would need to increase from 82 087 kT in 2018 to 129 000 kT by 2050. The Food and Agriculture Organization states that global production of aquatic animals was 178 million tonnes in 2020. Capture fisheries contributed 90 million tonnes (51%) of this. For capture fisheries to be a sustainable practice in alignment with UN sustainability goals, ocean conservation measures must be followed and processing of capture fisheries may need to adapt food‐processing strategies already used extensively in the processing of dairy, meat, and soy. These are required to add value to reduced fish landings and sustain profitability.
Electroconductive agarose hydrogels modulate mesenchymal stromal cell adhesion and spreading through protein adsorption
Authors: Casella Alena , Panitch Alyssa , Leach J. Kent
Published: January 2023

Electrically conductive biomaterials direct cell behavior by capitalizing on the effect of bioelectricity in tissue homeostasis and healing. Many studies have leveraged conductive biomaterials to influence cells and improve tissue healing, even in the absence of external stimulation. However, most studies using electroactive materials neglect characterizing how the inclusion of conductive additives affects the material's mechanical properties, and the interplay between substrate electrical and mechanical properties on cell behavior is poorly understood. Furthermore, mechanisms dictating how electrically conductive materials affect cell behavior in the absence of external stimulation are not explicit. In this study, we developed a mechanically and electrically tunable conductive hydrogel using agarose and the conductive polymer PEDOT:PSS. Under certain conditions, we observed that the hydrogel physical and electrical properties were decoupled. We then seeded human mesenchymal stromal cells (MSCs) onto the hydrogels and observed enhanced adhesion and spreading of MSCs on conductive substrates, regardless of the hydrogel mechanical properties, and despite the gels having no cell‐binding sites. To explain this observation, we measured protein interaction with the gels and found that charged proteins adsorbed significantly more to conductive hydrogels. These data demonstrate that conductivity promotes cell adhesion, likely by facilitating increased adsorption of proteins associated with cell binding, providing a better understanding of the mechanism of action of electrically conductive materials.
Bone Deterioration in Response to Chronic High-Altitude Hypoxia Is Attenuated by a Pulsed Electromagnetic Field Via the Primary Cilium/HIF-1α Axis
Authors: Hao Xiaoxia , Wang Dan , Yan Zedong , Ding Yuanjun , Zhang Juan , Liu Juan , Shao Xi , Liu Xiyu , Wang Lu , Luo Erping , Cai Jing , Jing Da
Published: January 2023

Chronic high-altitude hypoxia induces irreversible abnormalities in various organisms. Emerging evidence indicates that hypobaric hypoxia markedly suppresses bone mass and bone strength. However, few effective means have been identified to prevent such bone deficits. Here, we assessed the potential of pulsed electromagnetic fields (PEMFs) to noninvasively resist bone deterioration induced by hypobaric hypoxia. We observed that exogenous PEMF treatment at 15 Hz and 20 Gauss (Gs) improved the cancellous and cortical bone mass, bone microstructure, and skeletal mechano-properties in rats subjected to chronic exposure of hypobaric hypoxia simulating an altitude of 4500 m for 6 weeks by primarily modulating osteoblasts and osteoblast-mediated bone-forming activity. Moreover, our results showed that whereas PEMF stimulated the functional activity of primary osteoblasts in hypoxic culture in vitro, it had negligible effects on osteoclasts and osteocytes exposed to hypoxia. Mechanistically, the primary cilium was found to function as the major electromagnetic sensor in osteoblasts exposed to hypoxia. The polycystins PC-1/PC-2 complex was identified as the primary calcium channel in the primary cilium of hypoxia-exposed osteoblastic cells responsible for the detection of external PEMF signals, and thereby translated these biophysical signals into intracellular biochemical events involving significant increase in the intracellular soluble adenylyl cyclase (sAC) expression and subsequent elevation of cyclic adenosine monophosphate (cAMP) concentration. The second messenger cAMP inhibited the transcription of oxygen homeostasis-related hypoxia-inducible factor 1-alpha (HIF-1α), and thus enhanced osteoblast differentiation and improved bone phenotype. Overall, the present study not only advances our understanding of bone physiology at high altitudes, but more importantly, proposes effective means to ameliorate high altitude-induced bone loss in a noninvasive and cost-effective manner. © 2023 American Society for Bone and Mineral Research (ASBMR).

Abstract

Schematic diagram showing the mechanism whereby PEMF treatment counteracts bone loss resulting from chronic hypobaric hypoxia.
New association between splicing factor‐coding gene polymorphisms and the risk of acute lymphoblastic leukemia in southern Chinese children: A five‐center case–control study
Authors: Deng Decheng , Luo Ailing , Li Ming , Yan Yaping , Cai Mansi , Liu Shanshan , Liu Xiaodan , Wang Xueliang , Zhang Xiaohong , Jiang Hua , Liu Xiaoping
Published: January 2023

Background

The role of splicing factor‐coding gene polymorphisms in pediatric acute lymphoblastic leukemia (ALL) susceptibility is still unclear.

Methods

A case–control designed model was used to estimate the overall risk of pediatric ALL and five single nucleotide polymorphisms (SNPs) of splicing factor‐coding genes in 808 cases and 1,340 controls, which were genotyped using a TaqMan assay. Stratified analysis was performed to explore the association of rs2233911 genotype and pediatric ALL susceptibility. The influence of splicing factor arginine/serine‐rich 1 (SFRS1) polymorphisms on the sensitivity to different chemotherapeutic regimens based on minimal residual disease (MRD) levels was analyzed. The haplotype analysis was adopted to evaluate the association between inferred haplotypes of the splicing factor‐coding genes and pediatric ALL risk.

Results

Among the five analyzed SNPs, SFRS1 rs2233911 AG/GG exhibited a significant association with increased pediatric ALL risk. The stratified analysis further identified the harmful effect of SFRS1 rs2233911 AG/GG in specific subgroups. Moreover, rs2233911 AG/GG had a protective effect on MRD in marrow of ≥0.01%  12 weeks of Chinese Children Cancer Group chemotherapeutics, but provided a harmful effect on MRD in the marrow of ≥0.01% at days 15–19 of the South China Children Leukemia Group chemotherapeutics. Haplotype analysis of these five SNPs yielded haplotypes ACGCC and ACGTC significantly correlating with increased pediatric ALL susceptibility. On the contrary, haplotypes GCATG and GTACC were linked with remarkably decreased pediatric ALL risk.

Conclusion

SFRS1 gene polymorphism was associated with increased pediatric ALL risk and indicated that rs2233911 AG/GG might be a potential biomarker for choosing chemotherapeutics.
The longitudinal influence of tDCS on occipital GABA and glutamate/glutamine levels in episodic migraineurs
Authors: Pohl Heiko , Wyss Patrik , Sandor Peter S. , Schoenen Jean , Luechinger Roger , O'Gorman Ruth , Riederer Franz , Gantenbein Andreas R. , Michels Lars
Published: January 2023

This study investigated differences in the concentration of gamma‐aminobutyric acid (GABA) and the combination of glutamine and glutamate (as GLX) in the early visual cortex of patients with episodic migraine and the influence of transcranial direct current stimulation (tDCS) on GABA and GLX. In this single‐blind, sham‐controlled trial, we randomly assigned patients with episodic migraine to receive daily anodal tDCS or sham stimulation. In addition, we included healthy controls. We acquired proton MR spectroscopy data of the visual cortex with 3 Tesla MRI at baseline and from migraine patients directly after the stimulation period and 4 months later. In 22 migraineurs and 25 controls, the GABA and the GLX concentrations did not differ at baseline between the groups. tDCS resulted in reduced concentrations of GABA but not GLX or the migraine frequency directly after the stimulation period, but not 4 months later. The changes in the levels of GABA in the early visual cortex of patients with episodic migraine in the interictal period suggest an effect of tDCS that allowed for subsequent changes in the migraine frequency. However, we might have missed relevant variations in the concentrations of these neurotransmitters during the follow‐up period, as changes in migraine frequency appeared after the first MRI and disappeared before the second.
Revisiting the late Quaternary fossiliferous infills of Cathedral Cave, Wellington Caves (central eastern New South Wales, Australia)
Authors: Fusco Diana A. , Arnold Lee J. , Gully Grant A. , Levchenko Vladimir A. , Jacobsen Geraldine E. , Prideaux Gavin J.
Published: January 2023

The Wellington Caves were the first Australian locality from which Europeans collected and analysed vertebrate fossils. Within this system, Cathedral Cave contains Australia's stratigraphically deepest sequence of fossil‐bearing infill sediments, the age and depositional history of which has been poorly understood. Here we present results from a new excavation of the upper 4.2 m of the deposit, reanalysing the stratigraphy, petrography, sedimentology and geochemistry, and employing optically stimulated luminescence dating, radiocarbon dating and Bayesian age modelling to establish a robust chronology. We recognise 13 sedimentary layers and sublayers in two stratigraphic units. Unit 2 accumulated between 72 000 ± 5000 and 38 000 ± 7000 years ago as sediments and animals entered through a now‐blocked ceiling hole. Accumulation halted for around 30 000 years when the hole closed. Unit 1 accumulated when deposition was reinitiated around 7000 ± 2000 years ago, continuing through to a few hundred years ago. Our chronology refutes earlier dating of the deposit, which suggested that extinct Pleistocene megafauna taxa persisted locally until the Last Glacial Maximum. It confirms the deposit as one of the few in Australia that formed during the interval of major environmental upheaval marked by the arrival of humans, variable climate and the extinction of many megafaunal species.
Danggui Buxue Decoction: Comparative pharmacokinetic research on six bio‐active components in different states by ultra‐performance liquid chromatography‐tandem mass spectrometry after oral administration
Authors: Zhao Hedi , Qi Miao , Gong Yuan , Chen Han , Wang Dan , Fan Jing , Wang Yanmin , Wang Jingjuan
Published: January 2023

Danggui Buxue Decoction is a classic formula containing Astragali Radix and Angelicae Sinensis Radix in a 5:1 ratio and has been extensively used to treat blood deficiency for thousands of years. The aim of the study was to investigate the differences in plasma protein binding, pharmacokinetics, and tissue distribution of Danggui Buxue Decoction in normal and blood‐deficient rats by ultra‐performance liquid chromatography‐tandem mass spectrometry. The effects on peripheral blood routine were verified. The compounds exhibited higher plasma protein binding and absorption in the model group compared to the control group, except formononetin. The six ingredients were distributed widely, and the highest concentrations were detected in the heart and uterus. As has been demonstrated in the previous study of the effect of Danggui Buxue Decoction, its potential is to serve as an effective traditional Chinese medicine formula for treating cardiovascular diseases and impacting estrogenic properties, which reveals the potential target organs of Danggui Buxue Decoction the heart and uterus. Our findings suggested that the absorption and distribution of different components in Danggui Buxue Decoction varies depending on the pathological state, molecular weight, lipid solubility, transporter‐mediated efflux, and other factors.
Liquid Metal as a Liquid State Nucleating Agent for Poly(l‐lactide)
Authors: Peng Hao , He Yucheng , Fu Zhiwei , Zhou Jiancheng
Published: January 2023

This work for the first time reports that liquid metal (LM, gallium) behaves as a nucleating agent for the plastic poly(l‐lactide) (PLLA). The LM‐PLLA composites with different content (0–10%, by weight) of LM are fabricated by a twin crew extruder. The impacts of LM content on non‐isothermal and isothermal crystallization behavior are systematically investigated by calorimetry combing with Avrami's theory, determining an optimal LM content (2.5%) for advancing the crystallization of PLLA. Wide‐angle X‐ray diffraction (WAXD) shows that the excessive LM will interfere with the crystal structure of X%LM‐PLLA. As a kind of liquid state nucleating agent in plastic, the nucleation mechanism of LM for PLLA is attributed to the production of carboxylate ion clusters from the reaction between carboxylic acid on the end group of the PLLA chain and gallium, which is distinct from the epitaxy mechanism of previous solid nucleating agents.
Fast spin‐echo approach for accelerated B1 gradient–based MRI
Authors: Froelich Taylor , DelaBarre Lance , Wang Paul , Radder Jerahmie , Torres Efraín , Garwood Michael
Published: January 2023

Purpose

To expand on the previously developed ‐encoding technique, frequency‐modulated Rabi‐encoded echoes (FREE), to perform accelerated image acquisition by collecting multiple lines of k‐space in an echo train.

Methods

FREE uses adiabatic full‐passage pulses and a spatially varying RF field to encode unique spatial information without the use of traditional B0 gradients. The original implementation relied on acquiring single lines of k‐space, leading to long acquisitions. In this work, an acceleration scheme is presented in which multiple echoes are acquired in a single shot, analogous to conventional fast spin‐echo sequences. Theoretical analysis and computer simulations investigated the feasibility of this approach and presented a framework to analyze important imaging parameters of FREE‐based sequences. Experimentally, the multi‐echo approach was compared with conventional phase‐encoded images of the human visual cortex using a simple surface transceiver coil. Finally, different contrasts demonstrated the clinical versatility of the new accelerated sequence.

Results

Images were acquired with an acceleration factor of 3.9, compared with the previous implementation of FREE, without exceeding specific absorption rate limits. Different contrasts can easily be acquired without major modifications, including inversion recovery–type images.

Conclusion

FREE initially illustrated the feasibility of performing slice‐selective 2D imaging of the human brain without the need for a B0 gradient along the y‐direction. The multi‐echo version maintains the advantages that encoding provides but represents an important step toward improving the clinical feasibility of such sequences. Additional acceleration and more advanced reconstruction techniques could further improve the clinical viability of FREE‐based techniques.
Evidence of cerebral hypoperfusion consecutive to ultrasound‐mediated blood‐brain barrier opening in rats
Authors: Labriji Wafae , Clauzel Julien , Mestas Jean‐Louis , Lafond Maxime , Lafon Cyril , Salabert Anne‐Sophie , Hirschler Lydiane , Warnking Jan M. , Barbier Emmanuel L. , Loubinoux Isabelle , Desmoulin Franck
Published: January 2023

Purpose

This work aims to explore the effect of Blood Brain Barrier (BBB) opening using ultrasound combined with microbubbles injection on cerebral blood flow in rats.

Methods

Two groups of n = 5 rats were included in this study. The first group was used to investigate the impact of BBB opening on the Arterial Spin Labeling (ASL) signal, in particular on the arterial transit time (ATT). The second group was used to analyze the spatiotemporal evolution of the change in cerebral blood flow (CBF) over time following BBB opening and validate these results using DSC‐MRI.

Results

Using pCASL, a decrease in CBF of up to was observed in the target hemisphere, associated with an increase in arterial transit time. The latter was estimated to be in the BBB opening impacted regions against in the contralateral hemisphere. The spatio‐temporal analysis of CBF maps indicated a nonlocal hypoperfusion. DSC‐MRI measurements were consistent with the obtained results.

Conclusion

This study provided strong evidence that BBB opening using microbubble intravenous injection induces a transient hypoperfusion. A spatiotemporal analysis of the hypoperfusion changes allows to establish some points of similarity with the cortical spreading depression phenomenon.
On the status of greylag geese in Roman Paris: A linear and 2D geometric morphometric approach
Authors: Oueslati Tarek , Gruwier Ben
Published: January 2023

We investigate here the domestic status of goose remains from archaeological excavations of the Roman urban settlement of ParisLutecia. Within the diet of theParisiiadult goose competes with chicken in importance, thus offering abundant material for exploring the question of the domesticity of this bird. We first use linear and geometric morphometrics on modern tarsometatarsi of wild and domestic greylag geese to investigate potential morphological differences between the two forms. Afterwards, we apply this model on a Roman sample fromLutecia. The modern domestic breed shows notable differences in length and gracility of the tarsometatarsus compared with the wild specimens. In domestic males, the tarsometatarsi appear significantly longer and more robust compared with females. In wild greylag geese, we do not observe significant differences between males and females. Geometric morphometric analysis shows a modification of the shape in the domestic form, with increased robusticity and a bend of the shaft towards the distal end. Following this analysis, we examine the metrical specificities of the archaeological sample that shows only an increase in robusticity and no modification of length relative to the wild form. Our linear and geometric morphometric models clearly indicate that the majority of the Roman geese are domestic. Nevertheless, a smaller number of wild greylag geese are also present and must be considered as being sourced from hunting activities in the surroundings ofLutecia.
Fetal agenesis of the septum pellucidum: Ultrasonic diagnosis and clinical significance
Authors: Hu Xueyi , Shang Ning
Published: January 2023

Objective

To describe the prenatal ultrasound (US) findings, genetic results, and clinical outcomes of fetuses with suspected agenesis of the septum pellucidum (ASP) in the Chinese population.

Methods

This retrospective, single‐center study included a cohort of fetuses with ASP diagnosed by prenatal imaging over a 10‐year period. We evaluated US findings, associated anomalies, genetic results, and clinical outcomes. Prenatal and postnatal imaging findings were compared as well as the clinical outcome of delivery.

Results

Ninety patients were included, with a median follow‐up time of 36 months (1–96 months). Thirty‐six fetuses (40%) with isolated ASP were diagnosed by prenatal US or magnetic resonance imaging (MRI); 39 cases (43.3%) had ASP with central nervous system malformations and 15 cases (16.6%) had ASP with non‐CNS abnormalities. Additional imaging findings were supplemented with prenatal MRI in 13 cases. Genetic tests were performed on 32 patients, of whom six had abnormalities. Prenatal US results of 40 patients (40/70) diagnosed by referral hospitals did not correspond to our findings. Of the 38 patients with postnatal records, 11 had abnormal neurological development.

Conclusion(s)

The outcome of an isolated ASP is usually favorable; however, neurological developmental delay is commonly observed if it is combined with other malformations.
Fetal surgery is not associated with increased inflammatory placental pathology
Authors: Cardenas Maria C. , Cheek‐Norgan E. Heidi , Branda Megan E. , Norgan Andrew P. , Schenone Mauro H. , Lemens Maureen A. , Chakraborty Rana , Ruano Rodrigo , Enninga Elizabeth Ann L.
Published: January 2023

Objective

Fetal surgery has improved neonatal outcomes; however, it is unknown if the intervention contributes to the developmental of inflammatory pathologies in the placenta. Here, an association between fetal surgery and placental pathology was examined.

Method

This case‐control study compared pregnancies with fetal surgery (n = 22), pregnancies with an indication for fetal surgery but without an intervention being done (n = 13), and gestational‐age and fetus‐number matched controls (n = 36). Data on maternal, infant, and placental outcomes were abstracted. Additionally, immunohistochemistry identified expression of lymphoid and myeloid cells in the placenta on a subset of cases. Comparisons were performed using Kruskal‐Wallis or Pearson's chi‐squared tests.

Results

Maternal characteristics were comparable between groups. Most fetal interventions were for diaphragmatic hernia, spina bifida, or twin‐to‐twin transfusion syndrome. Fetuses who were operated on before birth were more likely to be born preterm (p = 0.02). There was no increase in the rate of observed placental pathologies or immune cell infiltration in fetal surgery cases compared to controls.

Conclusion

The data suggest that fetal surgery is not associated with increased inflammatory or morphologic pathology in the placenta. This observation supports the growing field of fetal surgery.
PD‐L1 expression by different scoring methods and different cutoff values and correlation with clinicopathological characteristics in gastric cancer: A retrospective study
Authors: Si Lixiang , Pan XiaoHua , He Kang , Sun Ling , Wang Yajing , Xu Xinyu , Lu Jianwei
Published: January 2023

We retrospectively enrolled 325 gastric cancer (GC) patients to investigate the associations of programmed death ligand‐1 (PD‐L1) expression with clinicopathological characteristics by different scoring methods and different cutoff values. PD‐L1 expression was evaluated by the tumor proportion score (TPS) and the combined positive score (CPS). The positive rate of PD‐L1 TPS ≥1%, CPS ≥1, CPS ≥5 and CPS ≥10 in our study were 12.0%, 87.4%, 69.8% and 42.2%, respectively. Multivariate analysis showed that PD‐L1 CPS ≥5 was related to high expression of Ki67 (OR = 2.658, 95% CI: 1.401–5.045, p = .003) and pTNM staging (p = .033). PD‐L1 CPS ≥10 was correlated with larger tumor size (OR = 2.322, 95% CI: 1.052–5.127, p = .037) and lymph node metastasis (OR = 2.495, 95% CI: 1.293–4.814, p = .006). It is expected that these results can provide a reference for screening GC patients with high PD‐L1 expression level.
Obtaining mesoscale singular vectors reflecting synoptic‐scale uncertainty by projection in phase space
Authors: Ono Kosuke
Published: January 2023

The choice of initial perturbation technique in regional ensemble prediction systems is important for forecasts of heavy rain events. Although the uncertainty at synoptic scale has a strong impact on the forecast performance of mesoscale phenomena, there is no established method for explicitly providing synoptic‐scale uncertainty when generating mesoscale initial perturbations. In this study, a new method of calculating mesoscale singular vectors (SVs) that reflect synoptic‐scale uncertainty by applying a regional targeting technique to a subspace of the model phase space spanned by global ensemble perturbations was developed. Comparison of the results of this new method with those of the original SVs showed that the new SVs with high growth rate corresponded to the original SVs with high growth rate, whereas the new SVs with relatively lower growth rate had a larger contribution from the global ensemble perturbations. The new SVs mitigated the tendency of the original SVs to localize over the southern sea of the computational domain, and the forecast errors were better captured by the new SVs than by the original SVs. Furthermore, the effect on forecast performance of the new SVs as initial perturbations was confirmed by using the operational regional ensemble prediction system at the Japan Meteorological Agency. It was found that the precipitation probability forecast performance was superior in the first half of the forecast period at all rainfall thresholds.
Optimal control of sampled‐data systems based on an optimized stochastic sampling
Authors: Wang Guoliang , Zhu Zhikang
Published: January 2023

This article addresses the optimal control problem of continuous‐time sampled systems closed by a stochastically sampled controller. A model based on the Poisson Counter processes is proposed to describe the stochastic sampling, while another sampling frequency cost function is developed. As a results, more than one cost function will be considered and more difficult. In order to deal with the optimal control problem, the stability problem is first analyzed, while both the control gain and sampling sequence are given in advance and without optimized. Then, based on the optimized sampling sequence, both finite‐ and infinite‐time nominally optimal controllers are designed respectively. Particularly, sufficient conditions for testing such optimal controllers existing or not are established by applying the above given results. Finally, some numerical examples are offered to verify the effectiveness and superiorities of the methods proposed in this study.
Place re‐making and sense of place after quarrying and social‐ecological restoration
Authors: Svobodova Kamila , Plieninger Tobias , Sklenicka Petr
Published: January 2023

Rapid urbanization increases pressure on extracting construction materials through quarrying, which is disrupting and re‐making places worldwide. In this study, we examine how people's place making and sense of place are reconfigured through quarrying. Taking a case study approach, we investigate perceptions of sense of place after quarrying and social‐ecological restoration in a limestone region of the Czech Republic. Our survey of 400 visitors shows that quarrying affects sense of place through feelings, activities, and quarry features. These can be predicted by socio‐demographic characteristics, experiences and preferences, and the context of a particular quarry. We conclude that sense of place and place making should be key themes of the sustainable development debate, as they help to better understand the human variables that constrain or enable socially just development. Our approach provides a conceptual basis for this by revealing the processes through which people iteratively recreate their connections to places shaped by long‐lasting disruptions, such as mining and quarrying, that erased prior socio‐cultural and material landscapes.
Applications of Bacteria Decorated with Synthetic DNA Constructs
Authors: Prasad Pragati K. , Motiei Leila , Margulies David
Published: January 2023

The advent of DNA nanotechnology has revolutionized the way DNA has been perceived. Rather than considering it as the genetic material alone, DNA has emerged as a versatile synthetic scaffold that can be used to create a variety of molecular architectures. Modifying such self‐assembled structures with bio‐molecular recognition elements has further expanded the scope of DNA nanotechnology, opening up avenues for using synthetic DNA assemblies to sense or regulate biological molecules. Recent advancements in this field have lead to the creation of DNA structures that can be used to modify bacterial cell surfaces and endow the bacteria with new properties. This mini‐review focuses on the ways by which synthetic modification of bacterial cell surfaces with DNA constructs can expand the natural functions of bacteria, enabling their potential use in various fields such as material engineering, bio‐sensing, and therapy. The challenges and prospects for future advancements in this field are also discussed.
Associative Liquid‐In‐Liquid 3D Printing Techniques for Freeform Fabrication of Soft Matter
Authors: Honaryar Houman , Amirfattahi Saba , Niroobakhsh Zahra
Published: January 2023

Shaping soft materials into prescribed 3D complex designs has been challenging yet feasible using various 3D printing technologies. For a broader range of soft matters to be printable, liquid‐in‐liquid 3D printing techniques have emerged in which an ink phase is printed into 3D constructs within a bath. Most of the attention in this field has been focused on using a support bath with favorable rheology (i.e., shear‐thinning behavior) which limits the selection of materials, impeding the broad application of such techniques. However, a growing body of work has begun to leverage the interaction or association of the two involved phases (specifically at the liquid–liquid interface) to fabricate complex constructs from a myriad of soft materials with practical structural, mechanical, optical, magnetic, and communicative properties. This review article has provided an overview of the studies on such associative liquid‐in‐liquid 3D printing techniques along with their fundamentals, underlying mechanisms, various characterization techniques used for ensuring the structural stability, and practical properties of prints. Also, the future paths with the potential applications are discussed.
Charge Separation in BaTiO3 Nanocrystals: Spontaneous Polarization Versus Point Defect Chemistry
Authors: Neige Ellie , Schwab Thomas , Musso Maurizio , Berger Thomas , Bourret Gilles R. , Diwald Oliver
Published: January 2023

The fate of photogenerated charges within ferroelectric metal oxides is key for photocatalytic applications. The authors study the contributions of i) tetragonal distortion, responsible for spontaneous polarization, and ii) point defects, on charge separation and recombination within BaTiO3 (BTO) nanocrystals of cubic and tetragonal structure. Electron paramagnetic resonance (EPR) in combination with O2 photoadsorption experiments show that BTO nanocrystals annealed at 600 °C have a charge separation yield enhanced by a factor > 10 compared to TiO2 anatase nanocrystals of similar geometries. This demonstrates for the first time the beneficial effect of the BTO perovskite nanocrystal lattice on charge separation. Strikingly, charge separation is considerably hindered within BTO nanoparticles annealed ≥ 600 °C, due to the formation of Ba–O divacancies that act as charge recombination centers. The opposing interplay between tetragonal distortion and annealing‐induced defect formation inside the lattice highlights the importance of defect engineering within perovskite nanoparticles.
Sulfur‐Bridged Bonds Heightened Na‐Storage Properties in MnS Nanocubes Encapsulated by S‐Doped Carbon Matrix Synthesized via Solvent‐Free Tactics for High‐Performance Hybrid Sodium Ion Capacitors
Authors: Zhang Hongyu , Liu Baolin , Lu Zhenjiang , Hu Jindou , Xie Jing , Hao Aize , Cao Yali
Published: January 2023

The exploitation of electrode materials with ability to balance capacity and kinetics between cathode and anode is a challenge for sodium‐ion hybrid capacitors (SIHCs). Mn‐based anode materials are limited by poor electrical conductivity, sluggish reaction kinetics, large volume variation, weak cycling stability, and inferior reversible capacity. Herein, MnS nanocubes encapsulated in S‐doped porous carbon matrix (MSC) with strong sulfur‐bridged bond interactions (CSMn) are successfully synthesized by solvent‐free tactics. The CSMn bonds generated between MnS and carbon significantly inhibit the aggregation of nanostructural MnS cubes, restrict the volume expansion, and stabilize the nanostructure, which improves the Na+ storage reversibility and stability. Moreover, S‐doped porous carbon enhances the electrical conductivity and electrons/ions diffusion rate, which boosts a fast kinetic reaction. As expected, MSC anode presents an outstanding reversible capacity of 600 mAh g‐1 at 0.2 A g‐1 and a long‐term stable capacity of 357 mAh g‐1 for 1000 cycles at a high current density of 10 A g‐1 in sodium‐ion batteries (SIBs). The as‐assembled SIHCs deliver a high energy density of 109 W h kg‐1 and a high power output of 98 W kg‐1, with 88% capacity retention at 2 A g‐1 after 2000 cycles and practical applications (55 LEDs can be lighted for 10 min).
Ageing among Black and non‐Hispanic White older adults: A community‐based system dynamics approach to examining quality of life
Authors: Trani Jean‐Francois , Giesecke Megan , Hovmand Peter , Miller Nicholas , Cartmill Mary Kate , Mandujano Acevedo Nicandro , Lee Sandra , Liem William , Gillani Braveheart , Babulal Ganesh
Published: January 2023

Older adults are living longer in the United States and the proportion of those belonging to minoritized groups is growing. The value and characteristics of quality of life (QoL) at an older age have becoming of central concern to policy makers. To investigate the wicked problem of ageing and QoL, we conducted and compared two group model building workshops in St. Louis City, one with 16 White and another with 10 Black American older adults, age 65 and older. Group model building workshops involve communities in the identification and testing of shared solutions to pressing and complex problems. Findings demonstrated that racial disparities in terms of material and environmental resources represent significant barriers to QoL for both Black and White participants. Results underscore the need to address social determinants of health that impede healthy ageing and damage well‐being and QoL of older adults.
Development of a Novel Strand Reduction Technology for the Continuous Casting of Homogeneous High‐Carbon Steel Billet
Authors: Gao Yubo , Bao Yanping , Wang Ying , Wang Min , Zhang Mengyun
Published: January 2023

Internal quality issues concerning center segregation, porosity, and internal crack are the major problems with respect to the production of high‐carbon steels billet with a continuous casting process. Herein, a heat transfer calculation model is developed, verified, and applied to calculate the appropriate casting speed and secondary cooling intensity of the continuous casting billet with a section size of 160 mm square during mechanical reduction processes. The mechanical reduction on the homogeneity of the billet is investigated by several field trails to improve the internal quality of the high‐carbon 82 A steel billet. Consequently, a superoptimum crack‐free high‐carbon steel billet with high homogeneity both in segregation and in compactness is successfully achieved through a novel strand reduction pattern, combined with consecutive multiroll soft reduction and single‐roll heavy reduction.
Industrial Trials on Preparation of Cerium‐Treated H13 Steel by Electroslag Remelting with Cerium‐Oxide Containing Slag
Authors: Wang Xijie , Li Guangqiang , Chen Yufei , Wang Qiang , Liu Yu
Published: January 2023

To realize an industrial production of a cerium‐treated electroslag remelted H13 steel, electroslag remelting (ESR) of H13 steel using a CaF2–CeO2–CaO–Al2O3 system slag combined with a Si–Ca reductant addition is studied. The influence of the Al2O3 content in the slag on the cerium treatment effect of cerium‐oxide‐containing slag is investigated to determine the appropriate slag. A 52.2 wt% CaF2–26.7 wt% CeO2–17.8 wt% CaO–3.3 wt% Al2O3 slag (RE‐Slag) is employed for the industrial ESR production of H13 steel. An H13 steel remelted by a 70 wt% CaF2–30 wt% Al2O3 slag (CA‐Slag) is used for comparison. Al2O3 can suppress the reduction of cerium oxide by changing the activities of slag components. ESR with RE‐Slag achieves a cerium treatment of H13 steel. However, an uneven distribution of Ce is obtained due to the limitation of the reductant addition method. The H13 steel remelted with RE‐Slag (RE‐Slag‐H13) has higher cleanliness, finer dendritic structures, and finer primary carbides than those of the steel remelted with CA‐Slag (CA‐Slag‐H13). Compared to the forged CA‐Slag‐H13 steel, the banded segregation of the RE‐Slag‐H13 steel is suppressed, and the impact toughness is increased by 30%.
Ultimate and fatigue limit states of existing steel railway bridges – LRFD with historical steel products and connection types
Authors: Kroyer Robert M. , Taras Andreas
Published: January 2023

The assessment of the load‐bearing capacity and fatigue strength of existing railway bridges has been playing an increasingly important role in the infrastructure management of railway operators for several years now. Currently, many bridge structures have been in operation longer than it was foreseen during their planning and construction. In addition, the axle loads on many lines, as well as the demands on the reliability of the verification results, have steadily increased. As the material properties and construction techniques in existing structures differ to some extent from nowadays structures, e.g., riveting instead of welding, it is important to provide engineers and operators with recommendations for the assessment of existing steel bridges. This article summarises the studies conducted as part of a research project initiated by Deutsche Bahn Netz AG for possible updates to DB RiL 805, which is used for the verification of railway bridges in the Deutsche Bahn (DB) network. The studies concerned the transition of verification concepts against static and fatigue loads used in the past to limit state verifications with partial safety factors in accordance with the Eurocodes. While initially related to an upgrade of a specific operator's design recommendation, the findings in this article are of more general nature and could form the basis for similar developments of recommendations for the assessment of existing, riveted structures independently throughout Europe.
Can southern Australian rainfall decline be explained? A review of possible drivers
Authors: McKay Roseanna C. , Boschat Ghyslaine , Rudeva Irina , Pepler Acacia , Purich Ariaan , Dowdy Andrew , Hope Pandora , Gillett Zoe E. , Rauniyar Surendra
Published: January 2023

Southern Australia's rainfall is highly variable and influenced by factors across scales from synoptic weather to large‐scale circulation and remote climate modes of variability. Anthropogenic climate change and natural variability modulate these factors and their interactions. However, studies often focus on changes in selected parts of the climate system with less emphasis on the system as a whole. As such, it is difficult to gain a complete understanding of how southern Australia's rainfall responds to broad‐scale changes in the climate system. We step through the existing literature on long‐term changes in synoptic‐to‐large‐scale atmospheric circulation and drivers of climate variability to form a more complete story of rainfall changes across southern Australia. This process reveals that the most robust change is the observed winter decline in rainfall as it is consistent with several changing climatic factors: decreasing rainfall from weather systems, strengthening subtropical ridge, poleward shifts in the Hadley Cell and the Southern Annular Mode, and increasing frequency of positive Indian Ocean Dipole events. In other seasons, particularly summer, changes in atmospheric circulation and drivers may not agree with observed rainfall changes, highlighting gaps in our knowledge of atmospheric dynamics and climate change processes. Future work should focus on research across temporal‐ and spatial‐scales, better understanding of jet interactions, the influence of stratospheric processes on the troposphere, and instances of contrasting trends in drivers and southern Australian rainfall changes.

This article is categorized under:

Paleoclimates and Current Trends > Modern Climate Change

Paleoclimates and Current Trends > Detection and Attribution

Assessing Impacts of Climate Change > Observed Impacts of Climate Change
Numerical simulation of MHD two‐dimensional flow incorporated with joule heating and nonlinear thermal radiation
Authors: Hussain Farooq , Nazeer Mubbashar , Mengal Abdullah , Hussain Asif , Shah Syed Ali Raza
Published: January 2023

The current investigation presents a numerical simulation of boundary layer flow with heat transfer. The study primarily emphasizes heat generation due to the influence of nonlinear thermal radiation. Moreover, the simultaneous effects of Joule heating and viscous dissipation have been incorporated for the thermal enhancement of the magnetohydrodynamics (MHD) on the convective boundary layer flow over a flat plate. Dimensional analysis is brought into use to determine the hydro and thermal boundary layer thickness for the two‐dimensional flow. Subsequently, the application of the suitable similarity transformation yields a nonlinear coupled flow problem with is solved numerically with the help of the Runge–Kutta Fehlberg (RKF) method incorporated with the Shooting technique. Moreover, this theoretical study highlights the immense mechanical and aeronautical applications of thermal radiation. In view of computational findings and simulating results, linear and nonlinear thermal radiation effects can also be investigated on fluids passing through a cylinder and channels. Finally, computational data tabulated against some pertinent parameters and parametric study reveal that non‐linear thermal radiation is more effective for highly viscous fluids.
Effects of viscous and darcy dissipation on fully developed natural convection flow in a composite channel partially filled with porous material: Homotopy perturbation method (HPM)
Authors: Ajibade Abiodun O. , Gambo Jeremiah J. , Jha Basant K.
Published: January 2023

A steady natural convection flow in a composite channel partially filled with porous material is investigated analytically in this paper. In this respect, the effects of heat generation due to viscous dissipation and darcy dissipation were considered in the energy equations of the porous region and that of clear fluid region. In addition, the Brinkmann extended Darcy model was applied to model the flow in the porous region. The coupled system of nonlinear ordinary differential equations that governed the flow is solved by the homotopy perturbation method. The analytical solution results for velocity, temperature, and Nusselt number are provided and analyzed. The investigation reveals that increase in the thickness of the porous region hampers the hydrodynamics while it promotes the thermodynamics within the composite channel.
A global analysis of resonance-enhanced light scalar dark matter
Authors: Binder Tobias , Chakraborti Sreemanti , Matsumoto Shigeki , Watanabe Yu
Published: January 2023

Abstract

We study a minimal model for a light scalar dark matter, requiring a light scalar mediator to address the core-cusp problem and interact with the standard model particles. We analyze the model comprehensively by focusing on the Breit-Wigner resonance for dark matter annihilation and self-scattering channels, considering the thermal relic abundance condition that includes the early kinetic decoupling effect, as well as the present and future constraints from collider, direct, and indirect dark matter detections. We found that the scalar dark matter with the mass of 0.3–2 GeV remains uncharted, which will be efficiently tested by the near future MeV gamma-ray observations.
Notes on higher-derivative conformal theory with nonprimary energy-momentum tensor that applies to the Nambu-Goto string
Authors: Makeenko Yuri
Published: January 2023

Abstract

I investigate the higher-derivative conformal theory which shows how the Nambu-Goto and Polyakov strings can be told apart. Its energy-momentum tensor is conserved, traceless but does not belong to the conformal family of the unit operator. To implement conformal invariance in such a case I develop the new technique that explicitly accounts for the quantum equation of motion and results in singular products. I show that the conformal transformations generated by the nonprimary energy-momentum tensor form a Lie algebra with a central extension which in the path-integral formalism gives a logarithmically divergent contribution to the central charge. I demonstrate how the logarithmic divergence is canceled in the string susceptibility and reproduce the previously obtained deviation from KPZ-DDK at one loop.