bluuebunny/crossref_metadata_2025 huggingface dataset:
Attenuated replication and damaging effects of SARS‐CoV‐2 Omicron variants in an intestinal epithelial barrier model
Authors: Volcic Meta , Nchioua Rayhane , Pastorio Chiara , Zech Fabian , Haußmann Isabell , Sauter Daniel , Read Clarissa , Walther Paul , Kirchhoff Frank
Published: July 2024

Many COVID‐19 patients suffer from gastrointestinal symptoms and impaired intestinal barrier function is thought to play a key role in Long COVID. Despite its importance, the impact of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) on intestinal epithelia is poorly understood. To address this, we established an intestinal barrier model integrating epithelial Caco‐2 cells, mucus‐secreting HT29 cells and Raji cells. This gut epithelial model allows efficient differentiation of Caco‐2 cells into microfold‐like cells, faithfully mimics intestinal barrier function, and is highly permissive to SARS‐CoV‐2 infection. Early strains of SARS‐CoV‐2 and the Delta variant replicated with high efficiency, severely disrupted barrier function, and depleted tight junction proteins, such as claudin‐1, occludin, and ZO‐1. In comparison, Omicron subvariants also depleted ZO‐1 from tight junctions but had fewer damaging effects on mucosal integrity and barrier function. Remdesivir, the fusion inhibitor EK1 and the transmembrane serine protease 2 inhibitor Camostat inhibited SARS‐CoV‐2 replication and thus epithelial barrier damage, while the Cathepsin inhibitor E64d was ineffective. Our results support that SARS‐CoV‐2 disrupts intestinal barrier function but further suggest that circulating Omicron variants are less damaging than earlier viral strains.
Intravenous amoxicillin‐clavulanic acid: prescribing practices in Australian hospitals
Authors: Chronas Alexandros , Thursky Karin , Mo Simone , Hall Lisa , James Rodney , Ierano Courtney
Published: July 2024

Background

Oral amoxicillin‐clavulanic acid, a broad‐spectrum antimicrobial and one of the most commonly prescribed antimicrobials in Australia, has demonstrated poor prescribing guideline compliance and appropriateness. This may have inadvertent impacts on patient care and safety, from adverse drug reactions to antimicrobial resistance. Intravenous (IV) amoxicillin‐clavulanic acid was first registered in Australia in 2017, reflecting a subsequent and immediate increase in use. There is a need to assess the quality of such prescribing.

Aim

To describe the quality of IV amoxicillin‐clavulanic acid prescriptions through assessing guideline compliance and appropriateness of use in Australian hospitals.

Method

A retrospective data analysis of IV amoxicillin‐clavulanic acid prescriptions from the Hospital National Antimicrobial Prescribing Survey database between 2013 and 2021. The main outcomes measured were guideline compliance and appropriateness. Ethical approval was granted by the Melbourne Health Human Research Ethics Committee (HREC/74195/MH‐2022).

Results

The proportion of prescriptions for IV amoxicillin‐clavulanic acid, compared to all other antimicrobials, increased from 0.02% (2013) to 2.3% (2021). Guideline compliance and appropriateness have overall decreased (by 18.9% and 16.7%, respectively). Over time, national guidelines predominantly replaced local guidelines as the primary guideline source for prescribing. The most common reason for inappropriateness was unnecessarily broad spectrum of activity (39.5%).

Conclusion

Intravenous amoxicillin‐clavulanic acid prescribing continues to increase throughout Australian hospitals, with notable reductions in guideline compliance and appropriateness. Since 2019, the increase in these outcomes coincided with updated national prescribing guidelines, evident by prescribers utilising national over local guidelines. These findings reinforce the concept that antimicrobial stewardship initiatives, including auditing, robust national guidelines and education, are crucial to optimise IV amoxicillin‐clavulanic acid prescribing.
Investigations of Laser‐Assisted Renal Denervation for Treatment of Resistant Hypertension
Authors: Hwang Junghyun , Shin Hwarang , Jung Minwoo , Kang Hyun Wook
Published: July 2024

Background and Objectives

Renal denervation (RDN) is an emerging surgical treatment for resistant hypertension. However, the current RDN using radiofrequency can cause undesirable thermal damage to the medial and luminal layers due to direct contact between the arterial lumen and energy source. The aim of this study is to evaluate the feasibility of the new laser‐assisted RDN by exploring the potential treatment conditions.

Methods

For ex vivo testing, six different treatment conditions (10 and 20 W applied for delivery of 300, 450, and 600 J) were tested on the porcine liver and renal artery (RA) by using a continuous wave 1064 nm laser wavelength. The ablated area in the liver tissue was measured to estimate the extent of the coagulated area. Histological evaluation was performed on the treated RA tissues to confirm the extent of thermal nerve damage.

Results

The ablated depth, length, and area in the liver tissue increased with laser power and total energy. According to the histological results, 20 W groups yielded more significant damage to the RA nerves than 10 W groups at the total energy of 300 J (0.0 ± 0.0 mm for 10 W vs. 2.9 ± 1.0 mm for 20 W), 450 J (1.9 ± 0.6 mm for 10 W vs. 6.8 ± 1.5 mm for 20 W), and 600 J (2.9 ± 0.4 mm for 10 W vs. 7.3 ± 0.8 mm for 20 W). The treated RA exhibited insignificant medial injury in depth (medial thinning ≤ 25%), and no difference in the medial thinning was found among the six groups (p = 0.4).

Conclusion

The current study demonstrated that the 1064 nm laser at 20 W with delivery of 450 J could effectively damage the RA nerves with no or minimal injury to the surrounding tissue. The proposed laser‐assisted RDN may enhance physiological effects with insignificant complications in in vivo situations. Further in vivo studies will be conducted to validate the current findings by evaluating the extent of blood pressure reduction and norepinephrine changes after the laser‐assisted RDN on a large animal model.
Fabricating Biodegradable Tissue Scaffolds Through a New Aggregation Triggered Physical Cross‐Linking Strategy of Hydrophilic and Hydrophobic Polymers
Authors: Kaga Elif , Kaga Sadik
Published: July 2024

In the study, a new strategy is presented to make PLGA (poly lactic‐co‐glycolic acid) and POEGMEMA (poly(oligo(ethylene glycol) methyl ether methacrylate)) based biodegradable and biocompatible tissue scaffold via a new physical cross‐linking method. The advantage of brushed structure of POEGMEMA polymer and the hydrophobic character of PLGA polymer is taken to make physically entangled network in aqueous media. The hydrophobic nature of PLGA allows to get scaffolds even at low ratio of PLGA (25%, w/w) when using POEGMEMA (yield: 86%). This strategy gives robust polymeric networks in aqueous media without using chemical reactions through high hydrophilic polymer content. Scaffolds with high POEGMEMA ratio (75%, w/w) show two times higher water uptake ratio (≈300%) and two times lower compression strength (19 kPa) compared to the ones with lower POEGMEMA content (50%, w/w). They also show desired degradation profiles in various aqueous solutions. While the scaffolds prepared with 25% and 50% PLGA are almost stable in first 20 days, they completely degrade in 40–50 days. Both scaffold formulations (25% PLGA‐75% POEGMEMA and 50% PLGA‐50% POEGMEMA) have similar proliferative properties for fibroblast cells. The scaffolds also do not show toxicity compared to control group according to live‐dead assay.
Coexistence of Hardening and Softening Phenomena in Elastomeric Polymers under Nano‐Impact Loading
Authors: Kumar Amritesh , Youssef George
Published: July 2024

This article reports the coexistence of hardening and softening phenomena when polyurea is submitted to repeated nano‐impacts with various impact forces while controlling the strain rate. The manifestation of these phenomena is further elucidated by interrogating ultraviolet irradiated samples under ambient and nitrogen atmospheres, wherein artificial weathering accelerates hardening by reducing the nano‐impact depths as a function of exposure duration while increasing the impact load, nano‐impact repetitions and strain rate sensitivity favored softening. A 21% and 48% increase in indentation depth are recorded after 100 repetitions at a relatively higher force (10 mN) at a low strain rate and low force (2.5 mN) at a relatively higher rate for pristine and weathered polyurea, respectively. Electron microscopy evidences the induced, progressive damage at the nanoscale based on the agglomeration of hard segments, reduced free volume, and weathering‐induced surface embrittlement.
Gold Nanoparticles‐Modified 2D Self‐Assembled Amphiphilic Peptide Nanosheets with High Biocompatibility and Photothermal Therapy Efficiency
Authors: Xu Youyin , He Peng , Gu Guanghui , Zhu Danzhu , Luan Xin , Mu Rongqiu , Wei Gang
Published: July 2024

Amphiphilic peptides have garnered significant attention due to their highly designable and self‐assembling behaviors. Self‐assembled peptides hold excellent potential in various fields such as biosensing, environmental monitoring, and drug delivery, owing to their remarkable biological, physical, and chemical properties. While nanomaterials formed by peptide self‐assembly have found widespread use in biomedical applications, the development of 2D peptide nanosheets based on the self‐assembly of amphiphilic peptides remains challenging in terms of rational design and morphology modulation. In this study, rationally designed amphiphilic peptide molecules are self‐assembled into peptide nanosheets (PNS) under specific conditions to encapsulate gold nanoparticles (AuNPs), resulting in the formation of AuNPs/PNS hybrid materials with high photothermal conversion efficiency. The findings demonstrate that 2D PNS enhances the overall photothermal therapy effect of the nanohybrid materials due to their larger hosting area for AuNPs and higher biocompatibility. The well‐designed amphiphilic peptides in this study offer insights into the structural design and functional modulation of self‐assembled molecules. In addition, the constructed biomimetic‐functional 2D inorganic/organic nanohybrid materials hold potential applications in biomedical engineering.
Characterizing T1 in the fetal brain and placenta over gestational age at 0.55T
Authors: Aviles Verdera Jordina , Tomi‐Tricot Raphael , Story Lisa , Rutherford Mary A. , Ourselin Sebastien , Hajnal Joseph V. , Malik Shaihan J. , Hutter Jana
Published: July 2024

Purpose

T1 mapping and T1‐weighted contrasts have a complimentary but currently under utilized role in fetal MRI. Emerging clinical low field scanners are ideally suited for fetal T1 mapping. The advantages are lower T1 values which results in higher efficiency and reduced field inhomogeneities resulting in a decreased requirement for specialist tools. In addition the increased bore size associated with low field scanners provides improved patient comfort and accessibility. This study aims to demonstrate the feasibility of fetal brain T1 mapping at 0.55T.

Methods

An efficient slice‐shuffling inversion‐recovery echo‐planar imaging (EPI)‐based T1‐mapping and postprocessing was demonstrated for the fetal brain at 0.55T in a cohort of 38 fetal MRI scans. Robustness analysis was performed and placental measurements were taken for validation.

Results

High‐quality T1 maps allowing the investigation of subregions in the brain were obtained and significant correlation with gestational age was demonstrated for fetal brain T1 maps () as well as regions‐of‐interest in the deep gray matter and white matter.

Conclusions

Efficient, quantitative T1 mapping in the fetal brain was demonstrated on a clinical 0.55T MRI scanner, providing foundations for both future research and clinical applications including low‐field specific T1‐weighted acquisitions.
Reduction of ringing artifacts induced by diaphragm drifting in free‐breathing dynamic pulmonary MRI using 3D koosh‐ball acquisition
Authors: Ding Zekang , She Huajun , Chen Qun , Du Yiping P.
Published: July 2024

Purpose

To reduce the ringing artifacts of the motion‐resolved images in free‐breathing dynamic pulmonary MRI.

Methods

A golden‐step based interleaving (GSI) technique was proposed to reduce ringing artifacts induced by diaphragm drifting. The pulmonary MRI data were acquired using a superior–inferior navigated 3D radial UTE sequence in an interleaved manner during free breathing. Successive interleaves were acquired in an incoherent fashion along the polar direction. Four‐dimensional images were reconstructed from the motion‐resolved k‐space data obtained by retrospectively binning. The reconstruction algorithms included standard nonuniform fast Fourier transform (NUFFT), Voronoi‐density‐compensated NUFFT, extra‐dimensional UTE, and motion‐state weighted motion‐compensation reconstruction. The proposed interleaving technique was compared with a conventional sequential interleaving (SeqI) technique on a phantom and eight subjects.

Results

The quantified ringing artifacts level in the motion‐resolved image is positively correlated with the quantified nonuniformity level of the corresponding k‐space. The nonuniformity levels of the end‐expiratory and end‐inspiratory k‐space binned from GSI data (0.34 ± 0.07, 0.33 ± 0.05) are significantly lower with statistical significance (p < 0.05) than that binned from SeqI data (0.44 ± 0.11, 0.42 ± 0.12). Ringing artifacts are substantially reduced in the dynamic images of eight subjects acquired using the proposed technique in comparison with that acquired using the conventional SeqI technique.

Conclusion

Ringing artifacts in the motion‐resolved images induced by diaphragm drifting can be reduced using the proposed GSI technique for free‐breathing dynamic pulmonary MRI. This technique has the potential to reduce ringing artifacts in free‐breathing liver and kidney MRI based on full‐echo interleaved 3D radial acquisition.
Nonnegative low multi‐rank third‐order tensor approximation via transformation
Authors: Song Guang‐Jing , Hu Yexun , Xu Cobi , Ng Michael K.
Published: July 2024

The main aim of this paper is to develop a new algorithm for computing a nonnegative low multi‐rank tensor approximation for a nonnegative tensor. In the literature, there are several nonnegative tensor factorizations or decompositions, and their approaches are to enforce the nonnegativity constraints in the factors of tensor factorizations or decompositions. In this paper, we study nonnegativity constraints in tensor entries directly, and a low rank approximation for the transformed tensor by using discrete Fourier transformation matrix, discrete cosine transformation matrix, or unitary transformation matrix. This strategy is particularly useful in imaging science as nonnegative pixels appear in tensor entries and a low rank structure can be obtained in the transformation domain. We propose an alternating projections algorithm for computing such a nonnegative low multi‐rank tensor approximation. The convergence of the proposed projection method is established. Numerical examples for multidimensional images are presented to demonstrate that the performance of the proposed method is better than that of nonnegative low Tucker rank tensor approximation and the other nonnegative tensor factorizations and decompositions.
Features of Importance in Nasal Endoscopy: Deriving a Meaningful Framework
Authors: Babahaji Layla M. , Ganeshan Vinayak , Nguyen Thinh S. , Ahmed Omar , Barton Blair M. , Chandra Rakesh , Chen Philip G. , Gudis David A. , Halawi Akaber , Higgins Thomas S. , Joe Stephanie A. , Kuan Edward C. , Marino Michael J. , Patel Zara M. , Ramakrishnan Vijay R. , Rangarajan Sanjeet V. , Riley Charles A. , Roxbury Christopher R. , Tabaee Abtin , Tang Dennis M. , Wu Arthur W. , Yim Michael T. , Bidwell Jonathan , McCoul Edward D.
Published: July 2024

Objective

Critical components of the nasal endoscopic examination have not been definitively established for either the normal examination or for clinical disorders. This study aimed to identify concordance among rhinologists regarding the importance of examination findings for various nasal pathologies.

Study Design

A consortium of 19 expert rhinologists across the United States was asked to rank the importance of findings on nasal endoscopy for 5 different sinonasal symptom presentations.

Setting

An online questionnaire was distributed in July 2023.

Methods

The questionnaire utilized JotForm® software and featured 5 cases with a set of 4 identical questions per case, each covering a common indication for nasal endoscopy. Rankings were synthesized into Normalized Attention Scores (NASs) and Weighted Normalized Attention Scores (W‐NASs) to represent the perceived importance of each feature, scaled from 0 to 1.

Results

General concordance was found for examination findings on nasal endoscopy within each case. The perceived features of importance differed between cases based on clinical presentation. For instance, in evaluating postnasal drip, the middle meatus was selected as the most important structure to examine (NAS, 0.73), with mucus selected as the most important abnormal finding (W‐NAS, 0.66). The primary feature of interest for mucus was whether it was purulent or not (W‐NAS, 0.67). Similar analyses were performed for features in each case.

Conclusion

The implicit framework existing among rhinologists may help standardize examinations and improve diagnostic accuracy, augment the instruction of trainees, and inform the development of artificially intelligent algorithms to enhance clinical decision‐making during nasal endoscopy.
Determination of optimum production and 3D printer application temperatures for hemp fiber reinforced polycarbonate composites
Authors: Ceylan Engin Irem , Cakici Alp Nese , Aytac Ayse
Published: July 2024

This study delves into optimizing production parameters and 3D printing (3Dp) conditions for alkaline‐treated 10% hemp fiber‐reinforced polycarbonate (PC) composites. Initially, composite filaments were extruded at 250°C (PCH250) and 230°C (PCH230) to assess the impact of varying melt mixing temperatures on thermal behavior. Thermal characterization was conducted using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). DSC analysis indicated consistent glass transition temperatures (Tg) across pure PC and the composites, while TGA revealed minimal thermal degradation in PCH230 compared to pure PC. Subsequently, to ascertain the optimal 3D printing temperature, specimens were printed at temperatures elevated by 10°C relative to their melt mixing temperatures (PCH250/260 and PCH230/240), followed by mechanical evaluation via tensile testing. PCH230/240 exhibited superior mechanical properties, demonstrating a 12% increase in tensile strength and a 29% increase in Young's modulus compared to pure PC. Additional testing at 230°C printing temperature (PCH230/230) demonstrated enhanced mechanical strength over PCH250/260 but inferior performance relative to PCH230/240, attributed to incomplete interlayer adhesion observed through SEM analysis. Consequently, the optimal composite melt mixing temperature was determined to be 230°C, with an accompanying 3D printing temperature of 240°C for optimal mechanical performance.

Highlights

3D printable, 5% NaOH treated hemp fiber reinforced polycarbonate composite.

Printing composite with 3D printing device at different temperatures

230°C process temperature gives the best thermal properties.

240°C 3Dp temperature provides the best mechanical and morphological properties.
A fast and effective stiffness prediction method for short fiber reinforced composites with skin‐core structure
Authors: Zhao Runtian , Wang Zhihui , Li Xiaodong , Gao Haifeng , Wu Ting , Li Yinhui , Liu Jianglin , Chen Zhanchun , Feng Jun , Liang Jianguo
Published: July 2024

The extrusion procedure used to manufacture Short Fiber Reinforced Composites (SFRCs) results in significant anisotropy in the components due to the skin‐core structure. While there are existing accurate stiffness prediction methods available, there is still a need in engineering for an efficient and cost‐effective prediction method. This work proposes an efficient, low‐cost and effective stiffness prediction method for skin‐core structure using the orientation averaging method and series–parallel model. Initially, the sample is analyzed using industrial CT and metallographic microscopy to ascertain the fiber characteristics and skin‐core dimensions. Furthermore, it is presumed that the skin and core are distinct materials and their stiffness is determined using the orientation averaging method. Finally, the stiffness of the sample is determined by employing a series–parallel model for analyzing stress–strain transmission, which involved merging the skin and core components. Experimental and finite element results confirm the method's accuracy, boasting a calculation time of 31.36 s and a maximum stiffness error below 10%. This method is expected to be applied to automotive, construction and other engineering fields to meet the demand for fast, cost‐efficient and effective stiffness prediction of SFRCs.

Highlights

A stiffness prediction method is proposed, which is no modeling required.

Combined with Hashin‐Tsai, orientation average method and series–parallel model.

The stiffness of skin‐core structure is predicted by this method within 31.36 s.

This method can be extended to more complex fiber orientation examples.
A comparative metabolomics analysis of Açaí (Euterpe oleracea Mart.) fruit, food powder, and botanical dietary supplement extracts
Authors: Heck Kabre L. , Yi Yuyan , Thornton Destini , Zheng Jingyi , Calderón Angela I.
Published: July 2024

Introduction

Euterpe oleracea Mart. (açaí) is a botanical of interest to many who seek functional foods that provide antioxidant and anti‐inflammatory properties. Cancer patients are increasingly taking botanical dietary supplements containing açaí to complement their conventional therapeutics, which may lead to serious adverse events. Before testing our açaí extracts in vitro for botanical‐drug interactions, the goal is to chemically characterize our extracts for compounds whose biological activity in açaí is unknown.

Objective

The objective of this work was to develop a chemical fingerprinting method for untargeted characterization of açaí samples from a variety of sources, including food products and botanical dietary supplement capsules, made with multiple extraction solvents.

Methods

An optimized LC–MS method was generated for in‐depth untargeted fingerprinting of chemical constituents in açaí extracts. Statistical analysis models were used to describe relationships between the açaí extracts based on molecular features found in both positive and negative mode ESI.

Results

In an attempt to elucidate the differences in metabolites among açaí extracts from different cultivars, we identified or tentatively identified 173 metabolites from the 16 extracts made from 6 different sources. Of these compounds, there are 138 reported in açaí for the first time. Statistical models showed similar yet distinct differences between the extracts tested based on the polarity of compounds present and the origin of the source material.

Conclusion

A high‐resolution mass spectrometry method was generated that allowed us to greatly characterize 16 complex extracts made from different sources of açaí with different extraction solvent polarities.
Adolescent school refusal and academic self‐efficacy: A latent profile and regression analysis
Authors: Pérez‐Marco María , Gonzálvez Carolina , Fuster‐Rico Andrea , Vicent María , Fernández‐Sogorb Aitana , Aparicio‐Flores María Del Pilar
Published: July 2024

School refusal is a serious problem that negatively affects academic performance, connection to school, and socioemotional well‐being of students. Numerous scientific works have suggested that school refusal is associated with internalizing problems. However, it is necessary to determine how this condition may affect certain academic variables, such as perceived academic self‐efficacy. This study has three objectives: to identify school refusal profiles according to the Kearney and Silverman functional model (1990); to analyze differences in means based on the identified profiles of perceived academic self‐efficacy; and to determine the predictive capacity of school refusal on perceived academic self‐efficacy. Participants consisted of 2357 Spanish students (56.8% girls), aged 13–17 (M = 15.24, SD = 1.26). They were administered the School Refusal Assessment Scale‐Revised (SRAS‐R) and the Academic Situation‐Specific Perceived Self‐Efficacy Scale (ASSPSE). Three profiles of school refusal were identified using Latent Profile Analysis, and the differential functioning of these profiles was determined using the academic self‐efficacy dimension. Mixed profiles of school refusal obtained the lowest mean scores on the academic self‐efficacy dimension. The findings are discussed with regard to the importance of enhancing perceived academic self‐efficacy to prevent school attendance problems in adolescents and young children.
Registration of ‘Coral’ pink bean
Authors: Gomez Francisco E. , Kelly James D. , Wright Evan M. , Awale Halima E. , Bales Scott
Published: July 2024

‘Coral’ (Reg. no. CV‐359, PI 705151) pink bean (Phaseolus vulgaris L.), developed by Michigan State University AgBioResearch was released in 2022 as a midseason, disease‐resistant, upright short vine bean cultivar with uniform dry down. Coral was developed with the pedigree breeding method to the F4 generation followed by pure line selection for disease, agronomic, and quality traits. Coral combines high yield potential with midseason maturity in a pink bean seed type. Over the span of 6 years of field trials, Coral produced an average yield of 3228 kg ha−1, flowered at 46 days, and matured in 97 days. Plants averaged 48 cm in height, with a lodging resistance score of 1.4, and seed size of 42 g 100 seed−1. Notably, Coral has outperformed ‘Rosetta’ by 8% across the 6‐year trial period and reached maturity 1 day earlier. It is well adapted to the intensively managed, narrow‐row, direct‐harvested production systems where beans are typically grown in Michigan and the Upper Midwest. Coral exhibits resistance to Bean common mosaic virus, is susceptible to anthracnose, has shown tolerance to common bacterial blight, and white mold. Additionally, it demonstrated tolerance to root rot caused by Rhizoctonia solani similar to Rosetta. Seed size of Coral (42 g 100 seed−1) is larger than Rosetta (37 g 100 seed−1). Seed of Coral meets industry standards for packaging and canning quality in the pink bean seed class.
Exploring regioselectivity in 1,3‐dipolar cycloaddition of thioamides, selenoamides, and amides with propadienyl cation derivatives using density functional theory
Authors: Naik Vanishree Shankar , Periyasamy Ganga
Published: July 2024

This study explores the potential mechanisms (Paths 1 and 2) involved in the regioselective dipolar cycloaddition of thioamides, selenoamides, and amides with propargyl alcohol using density functional theory (DFT). Our calculations reveal that the initial step involves the formation of a cation with catalyst. Subsequently, isomerization occurs between cations I and II via 1,3‐hydride transfer in the second step. We analyzed the global reactivity index and frontier molecular orbital (FMO) theory to gain insights into the mechanism. In the third step, chalcoamides attack cations I and II, forming an intermediate. The formation of a five‐member ring intermediate constitutes the fourth step, followed by hydrogen transfer to produce stable five‐member heterazole compounds in the final step. We demonstrated the influence of substituents in the electrophile by employing various electron‐withdrawing and donating groups. Additionally, we examined the effect of the dielectric medium on the reaction barrier using polarizable continuum model. Thus, this study provides valuable insights for the rational design of more efficient 1,3‐dipolar cycloaddition reactions yielding regioselective products.
Computing Molecular Descriptors of Boron Icosahedral sheet
Authors: Xavier D. Antony , Nair A. Theertha , Usman Ghani Muhammad , Baby Annmaria , Tchier Fairouz
Published: July 2024

Boron, the element which is in close proximity with carbon in the periodic table has been hypothesized to produce diverse two‐dimensional structures that differ from well‐studied 2D materials. Icosahedron , the monomers of which form the crystalline boron structure, appears as a recurring pattern in the chemistry of boron compounds, elemental boron and boron‐rich materials, functions as a building block in a majority of boron allotropes. The topological study of the icosahedral sheets is a necessary field to be investigated for the effective analysis and characterization of its physico‐chemical attributes without undertaking time‐consuming experimental research. The topological descriptors being expressed as numerical values enable scientists to compare and correlate data, which can be applied to quantitative structure‐activity relationships and quantitative structure‐property relationships modeling. In this study, various degree based molecular descriptors of the crystal boron icosahedral sheet has been formulated from a two‐dimensional lattice perspective using the ‐polynomial approach. To establish the significance of these descriptors in the study of chemical attributes, an efficient linear regression modeling has also been performed, enabling the prediction of properties of several other boron sheets.
Computational insights into phthalate ester‐linked VOCs: A density functional theory (DFT)‐based approach for chemical ionization mass spectrometry (CI‐MS) analysis
Authors: Bhatia Manjeet
Published: July 2024

Rationale

The presence of volatile organic compounds (VOCs), notably diethyl phthalate, dimethyl phthalate, di‐n‐butyl phthalate, di(2‐ethylhexyl) phthalate, and similar compounds in soft drinks, raises significant concerns due to their known or potential adverse health effects. Monitoring these compounds is imperative to comprehend their implications on human health and the overall quality of soft drinks. Chemical ionization mass spectrometry (CI‐MS) techniques emerge as powerful tools for VOC quantification in soft drinks, offering fast analysis times, high detection sensitivity, real‐time analysis capabilities, and versatility across various scientific fields.

Methods

Achieving absolute quantification of VOCs using proton transfer reaction mass spectrometry (PTR‐MS) presents challenges, with individual VOC calibration proving labor intensive. Theoretical approaches pioneered by Su and colleagues, including density functional theory (DFT), offer avenues for approximating VOC concentrations and understanding ion‐molecule reactions. Specifically, DFT method B3LYP/6–311++G(d, p) computes molecular parameters like dipole moment, polarizability, proton affinity, and ionization energy for large phthalate esters. Rate constants of ion‐molecule reactions are determined using the parametrized trajectory method under varying E/N and temperature conditions.

Results

The analysis of computed parameters across seven complex molecules reveals notable findings. Bis(2‐methoxyethyl) phthalate, for instance, exhibits a superior dipole moment, suggesting intensified electrostatic interactions with ions and heightened rate constants. The increased proton affinity observed in certain molecules renders them suitable for specific ionization methods. Furthermore, enthalpy change and free energy computations affirm the reactivity of ions with phthalate esters, with distinct variations noted in rate constants based on dipole moment and polarizability.

Conclusions

In conclusion, the parametrized trajectory method, coupled with computational analysis of molecular parameters, offers a means to compute rate constants for ion‐molecule reactions, enabling determination of VOC concentrations in soft drinks without external calibration standards in PTR‐MS analyses. The observed variations in rate constants with temperature and reagent ions align with collision theory principles and existing literature findings, underscoring the utility of these approaches in VOC identification and quantification using PTR‐MS.
Bound‐based control design for permanent magnet linear motor servo system with inequality constraints and uncertainties
Authors: Wu Qilin , Sun Hao , Ma Chao , Qin Qiang , Cheng Xin
Published: July 2024

The permanent magnet linear motor (PMLM) systems are widely applied in various engineering fields. However, the state inequality constraints and uncertainties of parameters and unknown external disturbances need to be further explored. In this article, first, a state transformation method is proposed for converting bounded states to unbounded states. As a result, the output state of system is limited within the expected boundary constraint. Then, a new control strategy is constructed. This strategy can ensure that the controlled system with uncertainties is uniformly bounded and uniformly ultimately bounded. Finally, the effectiveness of the controller and the state transformation method are verified through simulation of PMLM system. The inequality constraints of the output state are satisfied, and the system performance is improved.
Study on a user terminal‐assisted beam pointing measurement algorithm for very high‐throughput satellite systems
Authors: Qi Kaiqiang , Zhang Cheng , Zhou Yejun , Liu Kang
Published: July 2024

High‐throughput satellites play an important role in emergency disaster relief, maritime, and other fields. A new generation of high‐throughput satellites with large deployable antennas and broadband beamforming networks, namely, very high‐throughput satellites (VHTS), is developing towards hundreds, even thousands of extremely narrow beams with Tbps capacity, which puts forward higher requirements for satellite pointing and system construction costs. In order to solve the problem that those traditional beam pointing measurement and calibration algorithms are difficult to apply or the performance is limited, this paper builds a service beam pointing measurement and calibration architecture. A user terminal‐assisted beam pointing measurement algorithm based on the Gauss‐Newton method is proposed for the general case, which can effectively reduce the construction cost of onboard and ground pointing measurement system, and improve the measurement accuracies of three axes of the satellite. Simulation results demonstrate the excellent performance under the ideal scenario. To achieve the future engineering application under the non‐ideal scenario, the terminal positioning error can be first neglected, then the pattern processing error and the terminal signal measurement error must be reduced by decreasing the pattern sampling interval, increasing the number of participant terminals, and other means. By comparing with a traditional beam pointing measurement algorithm, the proposed algorithm can achieve much lower beam pointing error than the baseline.
Intrinsic and instrumental care in pen pal letters: Recognizing care in STEM classrooms
Authors: Pierson Ashlyn E. , Brady Corey E. , Lee Sarah J. , Shuler Deborah , Sengupta Pratim , Clark Douglas B.
Published: July 2024

Studies of both professional science practice and children's science learning show that care is not merely ancillary to disciplinary work but a core and generative constituent of science practice. In science education research, however, students' care is often overlooked. In this paper, we describe the expression of care across two STEM classrooms (6th and 9th grade) studying biology and ecology and participating in a pen pal exchange. We analyze artifacts from the pen pal exchange as well as students' retrospective interviews and written reflections. Two ways of expressing care surfaced in students' letters: caring for guppies and caring for pen pals. We describe each form of care using examples from our data. We find that students' care for guppies and pen pals was both instrumental (in service of their investigations) and intrinsic (positioning guppies and pen pals as inherently valuable). We then connect these findings to studies of care in children's science learning and in professional science. We discuss methodological and practical implications for recognizing and analyzing how students' care manifests in classrooms and for designing learning activities that cultivate care.
In Situ Hydroxide Growth over Nickel–Iron Phosphide with Enhanced Overall Water Splitting Performances
Authors: Hu Jian , Yin Jiayi , Peng Aoyuan , Zeng Dishu , Ke Jinlong , Liu Jilei , Guo Kunkun
Published: July 2024

In this work, three dimensional (3D) self‐supported Ni‐FeOH@Ni‐FeP needle arrays with core‐shell heterojunction structure are fabricated via in situ hydroxide growth over Ni‐FeP surface. The as‐prepared electrodes show an outstanding oxygen evolution reaction (OER) performance, only requiring the low overpotential of 232 mV to reach 200 mA cm−2 with the Tafel slop of 40 mV dec−1. For overall water splitting, an alkaline electrolyzer with these electrodes only requires a cell voltage of 2.14 V to reach 1 A cm−2. Mechanistic investigations for such excellent electrocatalytic performances are utilized by in situ Raman spectroscopy in conjunction with density functional theory (DFT) calculations. The computation results present that Ni‐FeOH@Ni‐FeP attains better intrinsic conductivity and the D‐band center (close to that of the ideal catalyst), thus giving superior excellent catalytic performances. Likewise, the surface Ni‐FeOH layer can improve the structural stability of Ni‐FeP cores and attenuate the eventual formation of irreversible FeOOH products. More importantly, the appearance of FeOOH intermediates can effectively decrease the energy barrier of NiOOH intermediates, and then rapidly accelerate the sluggish reaction dynamics, as well as further enhance the electrocatalytic activities, reversibility and cycling stability.
Rationally Designed L12‐Pt2RhFe Intermetallic Catalyst with High CO‐Tolerance for Alkaline Methanol Electrooxidation
Authors: Liang Lecheng , Xu Kaiyang , Liang Jinhui , Ye Shao , Zeng Binwen , Liu Quanbing , Song Huiyu , Du Li , Cui Zhiming
Published: July 2024

It is a grand challenge to deep understanding of and precise control over functional sites for the rational design of highly efficient catalysts for methanol electrooxidation. Here, an L12‐Pt2RhFe intermetallic catalyst with integrated functional components is demonstrated, which exhibits exceptional CO tolerance. The Pt2RhFe/C achieves a superior mass activity of 6.43 A mgPt
−1, which is 2.23‐fold and 3.53‐fold higher than those of PtRu/C and Pt/C. Impressively, the Pt2RhFe/C exhibits a significant enhancement in durability owing to its high CO‐tolerance and stability. Density functional theory calculations reveal that high performance of Pt2RhFe intermetallic catalyst arises from the synergistic effect: the strong OH binding energy (OHBE) at Fe sites induce stably adsorbed OH species and thus facilitate the dehydrogenation step of methanol via rapid hydrogen transfer, while moderate OHBE at Rh sites promote the formation of the transition state (Pt‐CO···OH‐Rh) with a low activation barrier for CO removal. This work provides new insights into the role of OH binding strength in the removal of CO species, which is beneficial for the rational design of highly efficient catalysts.
Electron‐Delocalization Across High Surface Entropy Sub‐1 nm Nanobelts Toward Enhanced Electrocatalytic Urea Oxidation
Authors: Cheng Xijun , Nie Siyang , Huang Yuan , Liu Qingda , Wu Liang , Wang Xun
Published: July 2024

Integration of inherently incompatible elements into a single sublattice, resulting in the formation of monophasic metal oxide, holds great scientific promise; it unveils that the overlooked surface entropy in subnanometer materials can thermodynamically facilitate the formation of homogeneous single‐phase structures. Here a facile approach is proposed for synthesizing multimetallic oxide subnanometer nanobelts (MMO–PMA SNBs) by harnessing the potential of phosphomolybdic acid (PMA) clusters to capture inorganic nuclei and inhibiting their subsequent growth in solvothermal reactions. Experimental and theoretical analyses show that PMA in MMO–PMA SNBs not only aids subnanometer structure formation but also induces in situ modifications to catalytic sites. The electron transfer from PMA, coupled with the loss of elemental identity of transition metals, leads to electron delocalization, jointly activating the reaction sites. The unique structure makes pentametallic oxide (PMO–PMA SNBs) achieve a current density of 10 mA cm−2 at a low potential of 1.34 V and remain stable for 24 h at 10 mA cm−2 on urea oxidation reaction (UOR). The exceptional UOR catalytic activity suggests a potential for utilizing multimetallic subnanometer nanostructures in energy conversion and environmental remediation.
The relevance of biomass‐based gases as energy carriers: A review
Authors: Radosits Frank K. , Ajanovic Amela , Harasek Michael
Published: July 2024

Climate change and the consequences of the energy crisis on the European energy markets require action to decrease the dependence on fossil fuels. Biomass‐based green gases can contribute to emission reduction goals and are therefore considered as essential energy carriers in the future energy system. The core objective of this work is a literature review on biomass‐based green gases covering important economic, environmental and policy‐related aspects of their use as energy carriers. The main obstacles to rapid deployment are the economic and environmental uncertainties. The production costs for biomethane and bio‐SNG vary from 51 to 134 EUR2020/MWh depending on the technology, size of the plant, and feedstock utilized. The current production costs are not economically feasible without policy support. Carbon taxes and incentives can act as effective measures to promote biomass‐based gases. Emission reductions for production and consumption are in the range of 45%–90% compared to natural gas and fossil‐based hydrogen. The system borders significantly affect the results, making it difficult to compare the findings from different studies. Therefore, more research needs to be conducted to evaluate the economic uncertainties for investors as well as the environmental impact of biomass‐based green gases.

This article is categorized under:

Sustainable Energy > Bioenergy
Robust clustering based on trimming
Authors: García‐Escudero Luis A. , Mayo‐Iscar Agustín
Published: July 2024

Clustering is one of the most widely used unsupervised learning techniques. However, it is well‐known that outliers can have a significantly adverse impact on commonly applied clustering methods. On the other hand, clustered outliers can be particularly detrimental to (even robust) statistical procedures. Therefore, it makes sense to combine concepts from Robust Statistics and Cluster Analysis to deal with both clusters and outliers simultaneously through robust clustering approaches. Among the existing robust clustering techniques, we focus on those that rely on (impartial) trimming. Trimming offers the user an easy interpretation, as standard well‐known clustering methods are applied after a fraction of the potentially most outlying observations is removed. This trimming approach, when combined with appropriate constraints on the clusters' dispersion parameters, has shown a good performance and can be implemented efficiently thorough available algorithms.

This article is categorized under:

Statistical Learning and Exploratory Methods of the Data Sciences > Clustering and Classification

Statistical and Graphical Methods of Data Analysis > Robust Methods
An overview of lipid constituents in lipid nanoparticle mRNA delivery systems
Authors: Wu Shiqi , Lin Lixin , Shi Lu , Liu Shuai
Published: July 2024

mRNA therapeutics have shown great potential for a broad spectrum of disease treatment. However, the challenges of mRNA's inherent instability and difficulty in cellular entry have hindered its progress in the biomedical field. To address the cellular barriers and deliver mRNA to cells of interest, various delivery systems are designed. Among these, lipid nanoparticles (LNPs) stand out as the most extensively used mRNA delivery systems, particularly following the clinical approvals of corona virus disease 2019 (COVID‐19) mRNA vaccines. LNPs are comprised of ionizable cationic lipids, phospholipids, cholesterol, and polyethylene glycol derived lipids (PEG‐lipids). In this review, we primarily summarize the recent advancements of the LNP mRNA delivery technology, focusing on the structures of four lipid constituents and their biomedical applications. We delve into structure–activity relationships of the lipids, while also exploring the future prospects and challenges in developing more efficacious mRNA delivery systems.

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies

Biology‐Inspired Nanomaterials > Lipid‐Based Structures

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Fitting Compton peaks from first principles in x‐ray fluorescence spectra
Authors: Tee B. P. E. , Ganly B. , Mcllquham J. D. , Giang P. , Van Haarlem Y.
Published: July 2024

A method to fit Compton profiles in x‐ray fluorescence (XRF) spectroscopy using a line shape calculated from first principles is proposed. The fitting procedure incorporates the Compton profile calculations and the double Compton scattering line shape algorithm. The results demonstrate the effectiveness of the fitting approach in accurately describing the measured scattering spectra, with good agreement observed between the fit and experimental data. The findings of this study can be used for more accurate characterization of the scattering peaks in XRF spectroscopy.
DK/Dπ scattering and an exotic virtual bound state at the SU(3) flavour symmetric point from lattice QCD
Authors: Yeo J. Daniel E. , Thomas Christopher E. , Wilson David J. ,   for the Hadron Spectrum collaboration
Published: July 2024

Abstract

Elastic S-wave scattering of a charm meson with a light pseudoscalar meson in JP = 0+ is investigated in the flavour $$ \overline{\textbf{3}} $$

3
¯

, 6 and $$ \overline{\textbf{15}} $$

15
¯

sectors at the SU(3)f flavour point using lattice QCD, working on three volumes with mπ ≈ 700 MeV. Large bases of interpolating operators are employed to extract finite-volume spectra, which are subsequently used with the Lüscher method to provide constraints on infinite-volume scattering amplitudes. Examining the singularities of the amplitudes, the S-wave amplitude in the flavour $$ \overline{\textbf{3}} $$

3
¯

sector is found to contain a deeply bound state, strongly coupled to elastic threshold, corresponding to the $$ {J}^P={0}^{+}\ {D}_{s0}^{\ast }(2317) $$

J
P

=

0
+

D

s
0

∗

2317

. In the exotic flavour 6 sector a virtual bound state is found at $$ \sqrt{s_{\textrm{pole}}} $$

s
pole

= 2510 – 2610 MeV, roughly 40 – 140 MeV below threshold, whereas the $$ \overline{\textbf{15}} $$

15
¯

channel shows weak repulsion.