bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimality conditions for a Timoshenko beam model
Authors: Yildirim Kenan
Published: February 2022

Optimality conditions for a Timoshenko beam model are derived in the maximum principle. For this aim, existence and uniqueness of the solution to the beam system and controllability properties of the system are discussed. Necessary optimality condition for the beam system, subjected to the rotary damping, external excitation, and mixed integral constraints including equality or/and inequality on the control function and state, is derived in the form of maximum principle. Besides obtaining that maximum principle is necessary condition for the optimality, it is also indicated sufficient optimality requirement is maximum principle in the presence of some convexity assumptions on the constraints.
Analysis of one‐dimensional nonlinear rheological consolidation of saturated clay considering self‐weight stress and Swartzendruber's flow rule
Authors: Cui Penglu , Cao Wengui , Xu Zan , Wei Yunbo , Li Huixin
Published: February 2022

Considering the nonlinear rheological properties of saturated clay, the modified unified hardening (UH) constitutive relation was introduced to describe the nonlinear rheological deformation. Meanwhile, Swartzendruber's flow law was used to simulate the non‐Darcian flow of pore water in the progress of rheological consolidation. Consequently, a nonlinear rheological consolidation model (NRCM), for one‐dimensional consolidation, that simultaneously incorporates nonlinear stress‐strain‐time relationship, Swartzendruber's flow, self‐weight stress, and variable permeability coefficient has been developed here. The finite volume method (FVM) was utilized to solve the NRCM system, and its effectiveness was verified by comparing with the existing consolidation data. The parametric analysis results indicate that the soil's nonlinear rheological effect induced the excess pore water pressure (EPWP)’s accumulation in the initial loading. This phenomenon became more significant when considering the self‐weight stress or as the initial overconsolidated parameter, soil thickness, and seepage parameter increased. In contrast, it weakened with the increase of external loading. Additionally, considering the self‐weight stress slowed down the whole dissipation of EPWP in the initial period of loading. Nevertheless, it accelerated the nonlinear consolidation process in the middle and late loading stages.
Effects of grain size, solution salinity and pH on the electrical response of oil‐bearing carbonate sands
Authors: Deng Yaping , Qian Jiazhong , Luo Qiankun , Ma Haichun , Ma Lei , Xu Kaijian
Published: February 2022

Researchers around the world have carried out numerous studies on the electrical response of oil‐contaminated silica sands. However, few studies consider the oil contamination in carbonate sands that exhibit quite different characteristics to silica sands. The purpose of this work is to study the influence of grain size (0.5–1.0, 1–3 and 3–5 mm), solution salinity (100, 10 and 1 Ω·m) and pH (4.58, 6.5 and 9.25) on the resistivity and saturation exponent of oil‐bearing carbonate sands. Experimental columns were packed with crushed limestone grains, solution and oil. Electrical resistivity measurements were subsequently performed on the packed columns. Grain size exhibits a complex effect on the electrical response of partially saturated limestone grains. Resistivity decreases slightly with increasing grain size when water saturation is greater than 0.4, while it shows an inconsistent trend when water saturation is lower than 0.4. The resulting saturation exponent n decreases slightly when grain size increases from 0.5–1 mm to 1–3 mm, while it shows a positive change in n values for grain size of 3–5 mm. Changes in solution salinity significantly influence the resistivity and saturation exponent of limestone grains, with higher solution salinity resulting in lower resistivity and higher saturation exponent. However, with solution pH increasing from 4.58 to 9.25, it shows very limited effect on the resistivity and saturation exponent of limestone grains. This can be attributed to the strong buffering ability of limestone. Effects of grain size, solution salinity and pH on the resistivity and saturation exponent of oil‐bearing carbonate sands were investigated. Resistivity is found to show a decreasing trend with increasing grain size from 0.5–1 mm to 3–5 mm above a certain saturation (e.g. Sw > 0.4), while it shows a rapid increase below a certain saturation (e.g., Sw0.4) for a larger grain size of 3–5 mm. Resistivity decreases and the saturation exponent increases with the increase of solution salinity for oil‐bearing carbonate sands. Resistivity and saturation exponent do not vary significantly with solution pH ranging from 4.58 to 9.25 for oil‐bearing carbonate sands.
A singularity‐free online neural network‐based sliding mode control of the fixed‐wing unmanned aerial vehicle optimal perching maneuver
Authors: Song Yansui , Tang Yong , Ma Bo , Xu Bin
Published: February 2022

The perching behavior of birds is very common in nature, but it is extraordinary for fixed‐wing unmanned aerial vehicles (UAVs), because of post‐stall maneuver. The main problems of the perching maneuver are weak control authority and strong model nonlinearity. This paper proposed a control method to realize the fixed‐wing perch maneuver. For the problem of weak control authority, an optimal trajectory is designed. And a feasible reference trajectory is given under the conditions of model dynamic characteristics and actuator constraints. For the problem of strong nonlinearity, a singularity‐free online neural network‐based sliding mode controller is designed. The simulation test shows that the proposed controller can ensure a reliable perching maneuver under the initial state deviation.
Boosting the Efficiency of Kesterite Solar Cell: Use of Ag Mixed Cu2ZnSnS4Intermediate Thin Film Layer
Authors: A Benisha Chris , Routray Soumyaranjan
Published: February 2022

Kesterite materials such as copper–zinc–tin–sulfide (CZTS) and copper–zinc–tin–selenide (CZTSe) are potential candidates for cost‐effective photovoltaic applications. However, the material suffers low carrier collection efficiency due to poor quality of thin film during deposition and in‐house defects. The use of Ag‐doped CZTS layer as an intermediate layer can save the device from such issues. Herein, the impact of ACZTS layer on solar cell performance is analyzed. Numerical investigation on the influence of different loss mechanisms such as radiative recombination and recombination through traps and defects on the performance of the device is presented. A remarkable efficiency is achieved in solar cell with the incorporation of intermediate ACZTS layer.
Diode Laser‐Crystallization for the Formation of Passivating Contacts for Solar Cells
Authors: Gawlik Annett , Glatthaar Raphael , Dellith Andrea , Jia Guobin , Dellith Jan , Terheiden Barbara , Plentz Jonathan
Published: February 2022

A new method of diode laser treatment of passivating contacts for solar cells application based on electron beam evaporated highly doped amorphous silicon (a‐Si) layers deposited on solar‐grade Czochralski wafers with SiOx tunneling layers is investigated. In a first step, an interface oxide is grown and a highly doped n‐type a‐Si layer is deposited on both sides by electron beam evaporation. In a next step, the laser treatment is applied. Two different scanning speeds of 15 and 20 mm s−1 are used. Electron backscattering diffraction and quasi‐steady‐state photo conductance measurements indicate that the a‐Si layer can be crystallized without breaking up the thin oxide layer. To determine the best parameters, the lifetime and the implied open‐circuit voltage for each laser power are measured. The first results show a fitted lifetime of 4.06 ms and an implied open‐circuit voltage up to 711 mV after a passivation step.
Pairwise joint modeling of clustered and high‐dimensional outcomes with covariate missingness in pediatric pneumonia care
Authors: Gachau Susan , Njagi Edmund Njeru , Molenberghs Geert , Owuor Nelson , Sarguta Rachel , English Mike , Ayieko Philip
Published: February 2022

Multiple outcomes reflecting different aspects of routine care are a common phenomenon in health care research. A common approach of handling such outcomes is multiple univariate analyses, an approach which does not allow for answering research questions pertaining to joint inference. In this study, we sought to study associations among nine pediatric pneumonia care outcomes spanning assessment, diagnosis and treatment domains of care, while circumventing the computational challenge posed by their clustered and high‐dimensional nature and incompletely recorded covariates. We analyzed data from a cluster randomized trial conducted in 12 Kenyan hospitals. There were varying degrees of missingness in the covariates of interest, and these were multiply imputed using latent normal joint modeling. We used the pairwise joint modeling strategy to fit a correlated random effects joint model for the nine outcomes. This entailed fitting 36 bivariate generalized linear mixed models and deriving inference for the joint model using pseudo‐likelihood theory. We also analyzed the nine outcomes separately before and after multiple imputation. We observed joint effects of patient‐, clinician‐ and hospital‐level factors on pneumonia care indicators before and after multiple imputation of missing covariates. In both pairwise joint modeling and separate univariate analysis methods, enhanced audit and feedback improved documentation and adherence to recommended clinical guidelines over time in six and five pneumonia care indicators, respectively. Additionally, multiple imputation improved precision of parameter estimates compared to complete case analysis. The strength and direction of association among pneumonia outcomes varied within and across the three domains of pneumonia care
Young‐type interference in soft lepton scattering of diatomic homonuclear molecules
Authors: Barp Marcos V. , Arretche Felipe
Published: February 2022

Interference patterns in the scattering of positrons and electrons by diatomic homonuclear molecules are ab initio calculated. Our results are compared to model potential calculations with incident particles in twisted and plane wave states. All calculations are obtained in the first Born approximation framework. The comparison of the elastic differential cross sections shows how an ab initio description of the electronic molecular structure influence the interference minima structure. The origin of such patterns is also discussed.
Weak synchronization and convergence in coupled genetic regulatory networks: Applications to damped oscillators and multistable circuits
Authors: Augier Nicolas , Chaves Madalena , Gouzé Jean‐Luc
Published: February 2022

The study of synchronization in coupled genetic networks is a very challenging topic that is usually analyzed on a case‐by‐case basis. Here we consider a general model of genetic networks and examine two forms of interconnection, either homogeneous or heterogeneous coupling, corresponding to coupling functions that are either equal or different from those governing the individual dynamics. In the case of individual subsystems having unique but different steady states, we prove that the homogeneous coupled system has a unique globally asymptotically stable steady state. Moreover, in the case of large coupling strength, we show that under suitable assumptions the network achieves weak synchronization in the sense that the individual steady states become arbitrarily close. In the heterogeneous case, stability conditions are more intricate and some stronger assumptions on the individual dynamics have to be made, under which we prove a similar weak synchronization result in the case of large coupling strength. We apply the results to the synchronization of damped oscillators and to the control of multistable systems.
Bias compensated stochastic gradient algorithm for identification of an ARX‐type nonlinear rational model and its application in modeling of the dynamic of the cellular toxicity
Authors: Jing Shaoxue , Kiely Janice , Luxton Richard
Published: February 2022

Nonlinear rational model (NRM) is a generalized nonlinear model, the NARMAX model and Volterra model can be regarded as its special cases. In this article, the parameter identification of a class of nonlinear rational models is studied. Due to the coupling of the model output and the information vector, the parameter identification of the NRM is very challenging. To reduce the complexity of the identification, the stochastic gradient algorithm is used. However, the estimate given by traditional stochastic gradient algorithm is biased. To obtain unbiased estimation, the bias is calculated by using the observations and the previous estimate and then compensated to the biased estimate. A variable factor considering the estimation error is introduced to speed up the algorithm. Theoretical analysis shows that the proposed algorithm can obtain an unbiased estimate and has the complexity of . The proposed algorithm is validated by a numerical example and is applied in modeling the dynamics of the cellular toxicity using the tetra‐ethyl ammonium chloride. Results show that the proposed algorithm can obtain an accurate estimate for the nonlinear rational model with less computation.
Rapid location technology of odor sources by multi‐UAV
Authors: Liu Yunping , Zhao Xun , Xu Jun , Zhu Shuaihui , Su Dongyan
Published: February 2022

A multi‐unmanned aerial vehicle (UAV) offers the advantages of flexibility, safety, and efficiency with respect to odor source localization. When the traditional particle swarm optimization (PSO) algorithm is used to locate the odor source, the search efficiency of the UAVs is reduced owing to unplanned search routes, and local extreme points and internal collisions may occur, making it impossible to quickly locate the odor source. In response to these problems, this paper proposes an improved particle swarm optimization (IPSO) algorithm, which combines the PSO with the Zigzag algorithm to preplan the search routes and improve the efficiency of the UAVs to search the plume. In addition, the distance between the UAVs is used as an adjustment factor to adaptively adjust the inertia weights of the particles to prevent the UAVs from falling into a local optimum during the plume‐tracking stage and further improve the positioning efficiency. Finally, the PSO combined with the artificial potential field algorithm is used to avoid the internal collision of the UAVs when tracking the plume. The algorithm is verified through simulations and physical experiments. The results show that the IPSO significantly improves the efficiency and can achieve rapid and effective location of the odor source, which verifies the effectiveness and applicability of the algorithm.
Sample size estimation using a latent variable model for mixed outcome co‐primary, multiple primary and composite endpoints
Authors: McMenamin Martina E. , Barrett Jessica K. , Berglind Anna , Wason James M. S.
Published: February 2022

Mixed outcome endpoints that combine multiple continuous and discrete components are often employed as primary outcome measures in clinical trials. These may be in the form of co‐primary endpoints, which conclude effectiveness overall if an effect occurs in all of the components, or multiple primary endpoints, which require an effect in at least one of the components. Alternatively, they may be combined to form composite endpoints, which reduce the outcomes to a one‐dimensional endpoint. There are many advantages to joint modeling the individual outcomes, however in order to do this in practice we require techniques for sample size estimation. In this article we show how the latent variable model can be used to estimate the joint endpoints and propose hypotheses, power calculations and sample size estimation methods for each. We illustrate the techniques using a numerical example based on a four‐dimensional endpoint and find that the sample size required for the co‐primary endpoint is larger than that required for the individual endpoint with the smallest effect size. Conversely, the sample size required in the multiple primary case is similar to that needed for the outcome with the largest effect size. We show that the empirical power is achieved for each endpoint and that the FWER can be sufficiently controlled using a Bonferroni correction if the correlations between endpoints are less than 0.5. Otherwise, less conservative adjustments may be needed. We further illustrate empirically the efficiency gains that may be achieved in the composite endpoint setting.
Cobalt Supported on BN Catalyst with High B‐O Defects and Its Efficient Hydrodeoxygenation Performance of HMF to DMF**
Authors: Bi Dandan , Chen Xiaoyan , Du Zhao , Guo Zhonglu , Liu Zhenya , Lin Jing , Huang Yang , Tang Chengchun , Chen Guifeng , Fang Yi
Published: February 2022

In this paper, a non‐noble catalyst was prepared by a simple homogeneous precipitation method and could be applied for 5‐hydroxymethylfurfural (HMF) hydrodeoxygenation (HDO) to 2, 5‐dimethylfuran (DMF). The catalyst was characterized by SEM, TEM, XRD, FT‐IR, BET, XPS, ICP and H2‐TPR. The cobalt species in the catalysts dispersed on the surface of boron nitride (BN) evenly. There is a strong interaction between BN and cobalt species in the Co/BN catalysts with vast B−O defects. Under the optimal conditions, HMF can be completely converted and the selectivity of Co/BN catalyst for DMF can reach as high as 91.67 %. It is crucial that the stability of the catalyst was maintained after five cycles by simple centrifugation. Due to its simple preparation process, low cost and high selectivity, the catalyst will be applied widely in the area of industrial catalysis.
Revisiting models of internationalization: Pre‐export phase and lateral rigidity of emerging market Small and Medium Enterprises
Authors: Mishra Mahima , Paul Justin , Czinkota Michael
Published: February 2022

The purpose of this paper is to revisit theories of internationalization and explore their export commencement processes from emerging market lenses. The paper combines the two important concepts, the pre‐export phase and lateral rigidity to deliberate the internationalization phenomenon of SMEs. The paper draws on extant literature on the SME internationalization process and applies qualitative methods to provide deep insights into the pre‐export phase. The study uses four longitudinal context‐based case studies based at India for generalization. The conceptualization and findings show that SMEs in emerging markets require processes and innovations from a strategic and planning perspective. Emerging market SMEs require a combination of resource‐building in the pre‐export phase and the right stimuli to overcome lateral rigidity to start internationalization. This paper addresses the phase before internationalization and the concept of lateral rigidity to provide a holistic view of SME internationalization from the emerging country's perspective.
The Central Dogma revisited: Insights from protein synthesis, CRISPR, and beyond
Authors: Ille Alexander M. , Lamont Hannah , Mathews Michael B.
Published: February 2022

Francis Crick advanced two distinct but interrelated fundamental principles of molecular biology: (1) the Sequence Hypothesis and (2) the Central Dogma. The Sequence Hypothesis defines biological information transfer as the residue‐by‐residue transfer of sequence information between nucleic acids and to proteins. This is commonly summarized as DNA ➔ RNA ➔ protein and is colloquially referred to as the Central Dogma. More specifically, however, the Central Dogma expounded by Crick included a critical restriction, stipulating that “once sequential information has passed into protein it cannot get out again.” Under this definition, the Central Dogma has stood the test of time despite challenges. In principle, a violation of the Central Dogma could transpire through synthetic biology or by natural occurrence. To address these possibilities, we draw insights from existing modes of information transfer in protein synthesis and from synthetic Clustered Regularly‐Interspaced Short Palindromic Repeats (CRISPR) gene‐editing. We introduce a three‐part evaluation scheme, which we apply to the CRISPR/Cas9 system and the more recent CRISPR prime editing system. Potential mechanisms by which engineered sequence editing systems might violate the Central Dogma are considered. We conclude that although information transfer in protein synthesis and CRISPR gene‐editing remain within the bounds of the Central Dogma, the underlying mechanisms point toward an avenue of synthetic biology that could directly violate the Central Dogma. Finally, we speculate on some of the theoretical and practical implications of a protein‐derived information transfer system.

This article is categorized under:

RNA Evolution and Genomics > Ribonomics

RNA Interactions with Proteins and Other Molecules > Protein‐RNA Interactions: Functional Implications

Translation > Mechanisms
Equity in Higher Education: Evidences, Policies and Practices. Setting the Scene
Authors: Amaral Alberto
Published: February 2022

Widening access to higher education became an issue of political concern after the Second World War. It aimed both at improving social justice by granting conditions of access to all social groups and by improving economic performance because a more educated population would contribute to the economic competitiveness of countries. Equity has two components, fairness—which implies that personal and social circumstances do not hinder achieving educational potential, and inclusion, which means that all are able to attain a basic standard of education. It was believed that social inequalities could be reduced through the massification of higher education and, although some progress has been made in terms of increased participation, inequalities seem to persist. Much of what happens in terms of inequity is related to higher education being a positional good. Social groups from deprived backgrounds are not in a good position to compete for positional goods, which have a tendency to be monopolised by social groups from privileged backgrounds. The positional character of higher education makes fairness difficult to attain. Inclusion policies, by promoting a progressive increase of parents with higher education degrees will contribute in a safe, even if slow way, to progressively lower the level of inequity.
Access and Inequality in US Higher Education: Policy Issues
Authors: Dill David
Published: February 2022

Because of the international reputation and positive socioeconomic impacts achieved by US higher education, current efforts at the ‘massification’ of other national systems often look to America for guidance. But with respect to equity of access to bachelor’s degree education, the US possesses a number of limitations. For example, regarding the percentage of young US adults who have completed tertiary education as well as measures of social mobility, the US now trails a number of EU nations. This chapter reviews US research on student access addressing the nature and impacts of US college and university financial aid, the informational and behavioural constraints confronting lower income student applicants, and the effects of higher education affirmative action programmes intended to correct past discrimination. The strengths and weaknesses of these US policies are explored as a possible guide to the design of college and university access policies in other countries.
The Persistence of Inequity in Brazilian Higher Education: Background Data and Student Performance
Authors: Bertolin Julio , McCowan Tristan
Published: February 2022

In the last three decades Brazil’s enrolments grew from approximately 1.5 million to more than 8 million students. Unlike the expansion in the 1990s, when few students from lower socioeconomic backgrounds gained access, the current expansion of Brazilian higher education is changing student profiles. The share of students from lower socioeconomic levels among enrolees and graduates has increased significantly. However, when analysing these changes in terms of the various courses/careers and modes of education present in the Brazilian higher education system, it becomes evident that there are still remnants of an elitist system displaying significant inequity. This chapter shows how the expansion going on in Brazil, despite including new students, does not achieve ‘horizontality’, and instead reproduces inequalities in one of the most unequal societies in the world.
Undergraduate Student Funding in England: The Challenges Ahead for Equity
Authors: Callender Claire
Published: February 2022

Since 1990, a series of cost-sharing policies in England have changed how higher education and undergraduates are funded. A funding system predicated on student loan debt emerged, informed by neo-liberal thinking and ideas underpinning the marketization of higher education. Annual tuition fees of £9000 were introduced in 2012 for all full-time undergraduates, repaid by loans with repayments linked to graduates’ ability to pay. Sustaining these reforms and evidenced in the policy rhetoric, are a range of unsubstantiated assumptions about their impact, the benefits of student loans, and their effect on student behaviour. Loans sought to protect students from tuition fee increases, to make higher education more affordable, to encourage and widen higher education participation, and to promote student choice. But these aims have been realised only partially, and the 2012 reforms can undermine these aims. Student loans have not been embraced equally by all students, as anticipated. The financial and psychic costs of borrowing can limit students’ higher education and post-graduation choices, opportunities, and experiences. But such occurrences are not random—they are socially stratified. Those students who are already disadvantaged are the most negatively affected. The student funding reforms in England, therefore, have helped to perpetuate rather than just ameliorate existing inequalities.
Data and Reflections on Access-Transition to Higher Education in Portugal
Authors: Baptista João , Sin Cristina , Tavares Orlanda
Published: February 2022

This chapter analyses inequalities in the transition from upper secondary to higher education in Portugal, using empirical data from the General-Directorate of Education and Science Statistics (DGEEC). It argues that educational inequalities are already present in Portuguese students’ trajectories before higher education and that the transition to higher education therefore reflects these different opportunities. The central argument is that socioeconomic status is the most important aspect that directly or indirectly conditions transition to higher education in Portugal, and thus is the primary source of inequality in participation. The findings also point to other factors similar to those already highlighted in the literature as responsible for inequalities in access to higher education: previous schooling, gender, different regional opportunities and selection and admission criteria, with socioeconomic status appearing to be transversal to and/or aggravate the influence of most of these other factors (except gender). Disadvantaged students who manage to surmount all the different obstacles and reach higher education belong to a group of resilient “academic survivors”. Based on the findings of this study, several areas of intervention are proposed.
Weyl anomalies of four dimensional conformal boundaries and defects
Authors: Chalabi Adam , Herzog Christopher P. , O’Bannon Andy , Robinson Brandon , Sisti Jacopo
Published: February 2022

Abstract

Motivated by questions about quantum information and classification of quantum field theories, we consider Conformal Field Theories (CFTs) in spacetime dimension d ≥ 5 with a conformally-invariant spatial boundary (BCFTs) or 4-dimensional conformal defect (DCFTs). We determine the boundary or defect contribution to the Weyl anomaly using the standard algorithm, which includes imposing Wess-Zumino consistency and fixing finite counterterms. These boundary/defect contributions are built from the intrinsic and extrinsic curvatures, as well as the pullback of the ambient CFT’s Weyl tensor. For a co-dimension one boundary or defect (i.e. d = 5), we reproduce the 9 parity-even terms found by Astaneh and Solodukhin, and we discover 3 parity-odd terms. For larger co-dimension, we find 23 parity-even terms and 6 parity-odd terms. The coefficient of each term defines a “central charge” that characterizes the BCFT or DCFT. We show how several of the parity-even central charges enter physical observables, namely the displacement operator two-point function, the stress-tensor one-point function, and the universal part of the entanglement entropy. We compute several parity-even central charges in tractable examples: monodromy and conical defects of free, massless scalars and Dirac fermions in d = 6; probe branes in Anti-de Sitter (AdS) space dual to defects in CFTs with d ≥ 6; and Takayanagi’s AdS/BCFT with d = 5. We demonstrate that several of our examples obey the boundary/defect a-theorem, as expected.
A clinical decision aid to discern patients without and with midfacial and mandibular fractures that require treatment (the REDUCTION-II study): a prospective multicentre cohort study
Authors: Rozema Romke , El Moumni Mostafa , de Vries Gysbert T. , Spijkervet Frederik K. L. , Verbeek René , Kleinbergen Jurrijn Y. J. , Bens Bas W. J. , Doff Michiel H. J. , van Minnen Baucke ,   The REDUCTION study group
Published: February 2022

Purpose

To assess the diagnostic accuracy of physical examination findings and to construct clinical decision aids to discern emergency department patients without and with midfacial and mandibular fractures that require treatment.

Methods

A prospective multicentre cohort study was conducted in four hospitals in the Netherlands. Consecutive maxillofacial trauma patients were included whereupon each patient underwent a standardized physical examination consisting of 15 and 14 findings for midfacial and mandibular trauma, respectively. The primary outcome was the decision whether to treat during the emergency department stay or within 24 h of admission. The diagnostic accuracy was calculated for the individual physical examination findings and ensuing clinical decision aids with the focus being on detecting midfacial and mandibular fractures that require active treatment.

Results

A total of 766 midfacial trauma patients were identified of whom 339 (44.3%) had midfacial fractures. Of those, 74 (21.8%) required active treatment. A total of 280 mandibular trauma patients were identified of whom 66 (23.6%) had mandibular fractures. Of those, 37 (56.0%) required active treatment. The decision aid for midfacial trauma consisting of facial depression, epistaxis, ocular movement limitation, palpable step-off, objective malocclusion and tooth mobility or avulsion had a sensitivity of 97.3 (90.7–99.3), a specificity of 38.6 (35.0–42.3), and a negative predictive value of 99.3 (97.3–99.8). The decision aid for mandibular trauma consisting of mouth opening limitation, jaw movement pain, objective malocclusion and tooth mobility or avulsion resulted in a sensitivity of 100.0 (90.6–100.0), a specificity of 39.1 (33.2–45.4), and a negative predictive value of 100.0 (96.1–100.0).

Conclusion

The clinical decision aids successfully identified midfacial and mandibular trauma patients requiring active fracture treatment and so may be useful in preventing unnecessary radiological procedures in the future.

Trial Registration

The study was registered at ClinicalTrials.gov with the identifier NCT03314480.
Reducing the contingency of the world: magic, oracles, and machine-learning technology
Authors: Larsson Simon , Viktorelius Martin
Published: February 2022

The concept of magic is frequently used to discuss technology, a practice considered useful by some with others arguing that viewing technology as magic precludes a proper understanding of technology. The concept of magic is especially prominent in discussions of artificial intelligence (AI) and machine learning (ML). Based on an anthropological perspective, this paper juxtaposes ML technology with magic, using descriptions drawn from a project on an ML-powered system for propulsion control of cargo ships. The paper concludes that prior scholarly work on technology has failed to both define magic adequately and use research into magic. It also argues that although the distinction between ML technology and magic is important, recognition of the similarities is useful for understanding ML technology.
In vivo study of dose-dependent antioxidant efficacy of functionalized core–shell yttrium oxide nanoparticles
Authors: Kassem Samr , Arafa Mahmoud M. , Yehya Manal M. , Soliman Mostafa A. M.
Published: February 2022

Herein, we assess the dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide. The antioxidant properties of these nanoparticles were investigated in three groups of Sprague–Dawley rats (10 per group) exposed to environmental stress daily for 1 week and one control group. Groups 2 and 3 were intravenously injected twice a week with YNPs at 0.3 and 0.5 mg at 2nd and 5th day of environmental stress exposure respectively. Different samples of blood and serum were collected from all experimental groups at end of the experiment to measure oxidative biomarkers such as total antioxidant capacity (TAC), hydroxyl radical antioxidant capacity (HORAC), oxygen radical antioxidant capacity (ORAC), malondialdehyde (MDA), and oxidants concentration as hydrogen peroxide (H2O2). The liver, brain, and spleen tissues were collected for fluorescence imaging and histopathological examination in addition to brain tissue examination by transmission electron microscope (TEM). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to estimate YNPs translocation and concentration in tissues which is consecutively dependent on the dose of administration. Depending on all results, poly EGMP YNPs (poly EGMP yttrium oxide nanoparticles) can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB). Also, the neuroprotective effect of YNPs opening the door to a new therapeutic approach for modulating oxidative stress–related neural disorders.

Highlights

• The dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide was assessed.

• The dose of administration directly affecting the brain, liver, and spleen tissues distribution, retention, and uptake of YNPs and direct correlation between the absorbed amount and higher dose administered.

• YNPs can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB).

Graphical abstract
Efficacy and safety of reperfusion treatments in middle-old and oldest-old stroke patients
Authors: Viticchi Giovanna , Potente Eleonora , Falsetti Lorenzo , Burattini Marco , Bartolini Marco , Buratti Laura , Pelliccioni Giuseppe , Silvestrini Mauro
Published: February 2022

Introduction

Intravenous thrombolysis (IT) and mechanical thrombectomy (MT) have significantly changed the clinical outcome of acute ischaemic stroke (AIS). Concerns about possible complications often reduce the use of these treatment options for older patients, preferentially managed with antiplatelet therapy (AT). Aim of this study was to evaluate, in a population of middle-old (75–84 years) and oldest-old (≥ 85 years) subjects, the efficacy and safety of different treatments for AIS (IT, IT + MT, MT or AT), mortality and incidence of serious complications.

Patients and methods

All patients aged over 75 years admitted for AIS in two Stroke Units were enrolled. The physician in each case considered all treatment options and chose the best approach. NIHSS and modified Rankin Scale (mRS) were obtained and differences between admission and discharge scores, defined as delta(NIHSS) and delta(mRS), were calculated. The relationship between delta(NIHSS), delta(mRS) and type of procedure was analysed with a GLM/Multivariate model. Differences in mortality and incidence of serious complications were analysed with the chi-square test.

Results

A total of 273 patients, mean age 84.07 (± 5.47) years, were included. The Delta(NIHSS) was significantly lower in patients treated with AT than in those treated with IT and MT (p < 0.009 and p < 0.005, respectively). Haemorrhagic infarction occurrence was significantly lower (p < 0.0001) among patients treated with AT (10.6%) or IT (16.7%) compared to MT (34.9%) or MT + IT (37.0%). No significant difference was observed for in-hospital mortality. Age did not influence the outcome.

Conclusions

Our results suggest that IT and AT are effective and relatively safe approaches in middle-aged and older patients.
Multispectral autofluorescence characteristics of reproductive aging in old and young mouse oocytes
Authors: Campbell Jared M. , Mahbub Saabah B. , Bertoldo Michael J. , Habibalahi Abbas , Goss Dale M. , Ledger William L. , Gilchrist Robert B. , Wu Lindsay E. , Goldys Ewa M.
Published: February 2022

Increasing age has a major detrimental impact on female fertility, which, with an ageing population, has major sociological implications. This impact is primarily mediated through deteriorating quality of the oocyte. Deteriorating oocyte quality with biological age is the greatest rate-limiting factor to female fertility. Here we have used label-free, non-invasive multi-spectral imaging to identify unique autofluorescence profiles of oocytes from young and aged animals. Discriminant analysis demonstrated that young oocytes have a distinct autofluorescent profile which accurately distinguishes them from aged oocytes. We recently showed that treatment with the nicotinamide adenine dinucleotide (NAD+) precursor nicotinamide mononucleotide (NMN) restored oocyte quality and fertility in aged animals, and when our analysis was applied to oocytes from aged animals treated with NMN, 85% of these oocytes were classified as having the autofluorescent signature of young animals. Spectral unmixing using the Robust Dependent Component Analysis (RoDECA) algorithm demonstrated that NMN treatment altered the metabolic profile of oocytes, increasing free NAD(P)H, protein bound NAD(P)H, redox ratio and the ratio of bound to free NAD(P)H. The frequency of oocytes with simultaneously high NAD(P)H and flavin content was also significantly increased in mice treated with NMN. Young and Aged + NMN oocytes had a smoother spectral distribution, with the distribution of NAD(P)H in young oocytes specifically differing from that of aged oocytes. Identifying the multispectral profile of oocyte autofluorescence during aging could have utility as a non-invasive and sensitive measure of oocyte quality.
Multilevel interactions between native and ectopic isoprenoid pathways affect global metabolism in rice
Authors: Pérez Lucía , Alves Rui , Perez-Fons Laura , Albacete Alfonso , Farré Gemma , Soto Erika , Vilaprinyó Ester , Martínez-Andújar Cristina , Basallo Oriol , Fraser Paul D. , Medina Vicente , Zhu Changfu , Capell Teresa , Christou Paul
Published: February 2022

Isoprenoids are natural products derived from isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). In plants, these precursors are synthesized via the cytosolic mevalonate (MVA) and plastidial methylerythritol phosphate (MEP) pathways. The regulation of these pathways must therefore be understood in detail to develop effective strategies for isoprenoid metabolic engineering. We hypothesized that the strict regulation of the native MVA pathway could be circumvented by expressing an ectopic plastidial MVA pathway that increases the accumulation of IPP and DMAPP in plastids. We therefore introduced genes encoding the plastid-targeted enzymes HMGS, tHMGR, MK, PMK and MVD and the nuclear-targeted transcription factor WR1 into rice and evaluated the impact of their endosperm-specific expression on (1) endogenous metabolism at the transcriptomic and metabolomic levels, (2) the synthesis of phytohormones, carbohydrates and fatty acids, and (3) the macroscopic phenotype including seed morphology. We found that the ectopic plastidial MVA pathway enhanced the expression of endogenous cytosolic MVA pathway genes while suppressing the native plastidial MEP pathway, increasing the production of certain sterols and tocopherols. Plants carrying the ectopic MVA pathway only survived if WR1 was also expressed to replenish the plastid acetyl-CoA pool. The transgenic plants produced higher levels of fatty acids, abscisic acid, gibberellins and lutein, reflecting crosstalk between phytohormones and secondary metabolism.
Pre-Training Without Natural Images
Authors: Kataoka Hirokatsu , Okayasu Kazushige , Matsumoto Asato , Yamagata Eisuke , Yamada Ryosuke , Inoue Nakamasa , Nakamura Akio , Satoh Yutaka
Published: February 2022

Is it possible to use convolutional neural networks pre-trained without any natural images to assist natural image understanding? The paper proposes a novel concept, Formula-driven Supervised Learning (FDSL). We automatically generate image patterns and their category labels by assigning fractals, which are based on a natural law. Theoretically, the use of automatically generated images instead of natural images in the pre-training phase allows us to generate an infinitely large dataset of labeled images. The proposed framework is similar yet different from Self-Supervised Learning because the FDSL framework enables the creation of image patterns based on any mathematical formulas in addition to self-generated labels. Further, unlike pre-training with a synthetic image dataset, a dataset under the framework of FDSL is not required to define object categories, surface texture, lighting conditions, and camera viewpoint. In the experimental section, we find a better dataset configuration through an exploratory study, e.g., increase of #category/#instance, patch rendering, image coloring, and training epoch. Although models pre-trained with the proposed Fractal DataBase (FractalDB), a database without natural images, do not necessarily outperform models pre-trained with human annotated datasets in all settings, we are able to partially surpass the accuracy of ImageNet/Places pre-trained models. The FractalDB pre-trained CNN also outperforms other pre-trained models on auto-generated datasets based on FDSL such as Bezier curves and Perlin noise. This is reasonable since natural objects and scenes existing around us are constructed according to fractal geometry. Image representation with the proposed FractalDB captures a unique feature in the visualization of convolutional layers and attentions.
Laparoscopic Small Bowel Length Measurement in Bariatric Surgery Using a Hand-Over-Hand Technique with Marked Graspers: an Ex Vivo Experiment
Authors: Slagter Nienke , van Wilsum Mette , de Heide Loek J. M. , Jutte Ewoud H. , Kaijser Mirjam A. , Damen Stefan L. , van Beek André P. , Emous Marloes
Published: February 2022

Introduction

Tailoring limb length in bariatric surgery is a subject of many studies. To acquire the optimal limb length, accurate measurement of the small bowel length is essential.

Objective

To assess the intra- and inter-individual variability of laparoscopic bowel length measurement using a hand-over-hand technique with marked graspers.

Method

Four bariatric surgeons and four surgical residents performed measurements on cadaver porcine intestine in a laparoscopic box using marked graspers. Each participant performed 10 times a measurement of three different lengths: 150, 180, and 210 cm. Acceptable percentage deviation from the goal lengths was defined as less than 10%, while unacceptable deviations were defined as more than 15%.

Results

The bariatric surgeons measured the 150-, 180-, and 210-cm tasks with 4% (CI 0.4, 9), − 6% (CI − 11, − 0.8), and 1% (CI − 4, 6) deviation, respectively. In total, the bariatric surgeons estimated 58 out of 119 times (49%) between the margins of 10% deviation and 36 times (30%) outside the 15% margin. Considerable inter-individual differences were found between the surgeons. The surgical residents underestimated the tasks with 12% (CI − 18, − 6), 16% (CI − 19, − 13), and 18% (CI − 22, − 13), respectively.

Conclusion

Bariatric surgeons estimated bowel length with on average less than 10% deviation. However, this still resulted in 30% of the measurements with more than 15% deviation. There were considerable inter-individual differences between the surgeons and residents structurally underestimated the bowel length. Ascertainment of measurement accuracy and adequate training is essential for bariatric procedures in which limb length is of importance.

Graphical abstract
Does the length of stay in hospital affect healthcare outcomes of patients without COVID-19 who were admitted during the pandemic? A retrospective monocentric study
Authors: Fluck David , Fry Christopher Henry , Rankin Suzanne , Lewis Andrea , Robin Jonathan , Rees Jacqui , Finch Jo , Jones Yvonne , Jones Gareth , Tudose Julia , Taylor Liz , Han Thang Sieu
Published: February 2022

Uncertainties remain if changes to hospital care during the coronavirus disease (COVID-19) pandemic had an adverse impact on the care-quality of non-COVID-19 patients. We examined the association of hospital length of stay (LOS) with healthcare quality indicators in patients admitted with general medical conditions (non-COVID-19). In this retrospective monocentric study at a National Health Service hospital (Surrey), data were collected from 1st April 2019 to 31st March 2021, including the pandemic from 1st March 2020. Primary admissions, in-hospital mortality, post-discharge readmission and mortality were compared between the pre-pandemic (reference group) and pandemic period, according to LOS categories. There were 10,173 (47.7% men) from the pre-pandemic and 11,019 (47.5% men) from the pandemic period; mean (SD) age 68.3 year (20.0) and 68.3 year (19.6), respectively. During the pandemic, primary admission rates for acute cardiac conditions, pulmonary embolism, cerebrovascular accident and malignancy were higher, whilst admission rates for respiratory diseases and common age-related infections, and in-hospital mortality rates were lower. Amongst 19,721 survivors, sex distribution and underlying health status did not significantly differ between admissions before the pandemic and during wave-1 and wave-2 of the pandemic. Readmission rates did not differ between pre-pandemic and pandemic groups within the LOS categories of < 7 and 7–14 days, but were lower for the pandemic group who stayed > 14 days. For patients who died within seven days of admission, in-hospital mortality rates were lower in patients admitted during the pandemic. Mortality rates within 30 days of discharge did not differ between pre-pandemic and pandemic groups, irrespective of the initial hospital LOS. Despite higher rates of admission for serious conditions during the pandemic, in-hospital mortality was lower. Discharge time was similar to that for patients admitted before the pandemic, except it was earlier during the pandemic for those who stayed > 14 days, There were no group differences in quality-care outcomes.