bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthetic Approaches for 15N‐Labeled Hyperpolarized Heterocyclic Molecular Imaging Agents for 15N NMR Signal Amplification by Reversible Exchange in Microtesla Magnetic Fields
Authors: Chukanov Nikita V. , Shchepin Roman V. , Joshi Sameer M. , Kabir Mohammad S. H. , Salnikov Oleg G. , Svyatova Alexandra , Koptyug Igor V. , Gelovani Juri G. , Chekmenev Eduard Y. 
Published: April 2021

AbstractNMR hyperpolarization techniques enhance nuclear spin polarization by several orders of magnitude resulting in corresponding sensitivity gains. This enormous sensitivity gain enables new applications ranging from studies of small molecules by using high‐resolution NMR spectroscopy to real‐time metabolic imaging in vivo. Several hyperpolarization techniques exist for hyperpolarization of a large repertoire of nuclear spins, although the 13C and 15N sites of biocompatible agents are the key targets due to their widespread use in biochemical pathways. Moreover, their long T1 allows hyperpolarized states to be retained for up to tens of minutes. Signal amplification by reversible exchange (SABRE) is a low‐cost and ultrafast hyperpolarization technique that has been shown to be versatile for the hyperpolarization of 15N nuclei. Although large sensitivity gains are enabled by hyperpolarization, 15N natural abundance is only ∼0.4 %, so isotopic labeling of the molecules to be hyperpolarized is required in order to take full advantage of the hyperpolarized state. Herein, we describe selected advances in the preparation of 15N‐labeled compounds with the primary emphasis on using these compounds for SABRE polarization in microtesla magnetic fields through spontaneous polarization transfer from parahydrogen. Also, these principles can certainly be applied for hyperpolarization of these emerging contrast agents using dynamic nuclear polarization and other techniques.
Oxyphosphonium Enolate Equilibria in a (4+1)‐Cycloaddition Approach toward Quaternary C3‐Spirooxindole Assembly
Authors: Gulotty Eva M. , Rodriguez Kevin X. , Parker Erin E. , Ashfeld Brandon L. 
Published: April 2021

AbstractAn efficient and convergent (4+1)‐cycloaddition strategy toward the construction of spirooxindole benzofurans that involves the intermediacy of an isatin‐derived oxyphosphonium enolate is presented. Mechanistic investigations employing in situ NMR analysis of the reaction mixture revealed a correlation between phosphonium enolate structure and product distribution that was heavily influenced by the solvent and reaction temperature.
Bis(8‐hydroxyquinoline) Ligands: Exploring their Potential as Selective Copper‐Binding Agents for Alzheimer's Disease
Authors: Oliveri Valentina , Vecchio Graziella 
Published: April 2021

AbstractAmyloid‐β (Aβ) aggregation, metal ion dyshomeostasis, and oxidative stress are pathological features of Alzheimer's disease (AD). Aβ and metal ions form metal‐Aβ complex species that influence the aggregation of Aβ and, in particular, redox metal ions such as Cu lead to the production of reactive oxygen species (ROS). To target metal coordination to Aβ and the reactivities of Cu−Aβ, metal chelating agents must extract Cu2+ from Aβ in AD pathological conditions. Bis(8‐hydroxyquinoline) ligands can extract Cu2+ from Aβ and therefore inhibit the Cu‐induced Aβ aggregation and the aerobic oxidation of ascorbate. In particular, N‐butyl‐2,2‐imino‐bis(8‐hydroxyquinoline) can selectively target Cu−Aβ reactivities in the presence of Zn2+ such as in AD brain patients. The ligands can release Cu in intracellular environments in the presence of a large excess of glutathione, contributing to restore Cu homeostasis.
Optimized Synthesis of Fmoc/Boc‐Protected PNA Monomers and their Assembly into PNA Oligomers.
Authors: Shaikh Ashif Y. , Björkling Fredrik , Nielsen Peter E. , Franzyk Henrik 
Published: April 2021

AbstractContinuous advancement of application of peptide nucleic acid (PNA) oligomers encouraged exploration of rapid and efficient synthesis of PNA monomers and oligomers. Among the PNA monomers developed, only a few are commonly used in automated PNA synthesis. Herein, we report short and efficient protocols suitable for large‐scale synthesis of Fmoc/Boc‐protected PNA monomers with advantageous solubility properties; these also facilitate purification due to the traceless nature of the Boc protecting group. Initially, several coupling reagents were screened for assembly of a pentamer containing all four nucleobases, and then the most promising reagents were tested in the synthesis of a decamer. The Fmoc/Boc‐protected monomers proved compatible with both manual synthesis and assembly on an automated peptide synthesizer at room temperature or at 40 °C. As compared to the commonly used coupling agent, 1‐[bis(dimethylamino)methylene]‐1H‐1,2,3‐triazolo[4,5‐b]pyridinium 3‐oxide hexafluorophosphate (HATU), both 2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium hexafluorophosphate (HBTU) and [ethyl cyano(hydroxyimino)acetato−O2]tri‐1‐pyrrolidinylphosphonium hexafluorophosphate (PyOxim) proved more favorable, with the latter being superior. A previously reported side reaction of guanine bases in the presence of benzotriazol‐1‐yl‐oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP) was not observed with the phosphonium salts.
Trends in referrals to liaison psychiatry teams from UK emergency departments for patients over 65
Authors: Crowther George , Chinnasamy Manimegalai , Bradbury Sarah , Shaw Laura , Ormerod Sara , Wilkinson Alison , Chubb Rebecca , Daher Mazen , Kumar Pramod , Gaskin Andrew , Williams Karen , Brennan‐Tovey Justine , Brown Angus , Stebbings Eleanor , Sahu Sunita , Smyth Roger , Kinsler Hilary , O'Connor Stephen , Wells Andrew , Overshott Ross , Junaid Kehinde , Mordekar Aparna , Humphries Jenny , James Karen , Mittal Shweta , Dasari Sarita , Grant‐Peterkin Hugh , Campbell Niall , West Robert , Tadros George , Sampson Elizabeth L. 
Published: April 2021

AbstractIntroductionThe number of people over the age of 65 attending Emergency Departments (ED) in the United Kingdom (UK) is increasing. Those who attend with a mental health related problem may be referred to liaison psychiatry for assessment. Improving responsiveness and integration of liaison psychiatry in general hospital settings is a national priority. To do this psychiatry teams must be adequately resourced and organised. However, it is unknown how trends in the number and type referrals of older people to liaison psychiatry teams by EDs are changing, making this difficult.MethodsWe performed a national multi‐centre retrospective service evaluation, analysing existing psychiatry referral data from EDs of people over 65. We described trends in the number, rate, age, mental health presentation, and time taken to assessment over a 7 years period.ResultsReferral data from 28 EDs across England and Scotland were analysed (n = 18,828 referrals). There was a general trend towards increasing numbers of people referred to liaison psychiatry year on year. Variability in referral numbers between different departments, ranged from 0.1 to 24.3 per 1000 ED attendances. The most common reasons for referral were mood disorders, self‐harm and suicidal ideas. The majority of referrals were assessed within 60 min, however there is variability between departments, some recording waits over 11 h.DiscussionThe data suggests great inter‐departmental variability in referral numbers. Is not possible to establish the cause of variability. However, the data highlights the importance of asking further questions about why the differences exist, and the impact that has on patient care.
Comparison of free‐living physical activity data obtained from a Fitbit Zip, the Apple iPhone Health app and a modified Bouchard Activity Record
Authors: Reynolds Rebecca C. , Smith Veronica M. , Macniven Rona 
Published: April 2021

AbstractIssue addressedPhysical activity tracking devices have potential to improve public health, but their data needs to be reliable. No study has compared movement data between the Fitbit Zip, Apple iPhone Health app and physical activity records in a community setting over 10 days.MethodsUniversity students aged 18+ years wore both a Fitbit Zip and an iPhone at/near their right waist and completed a modified Bouchard Activity Record (BAR) for 10 days in a free‐living setting. Comparisons were made between the Fitbit Zip and iPhone for the number of steps and the distance travelled and between the Fitbit Zip and BAR for the minutes of activity in three different intensities.ResultsEighteen students provided sufficient data for inclusion. There were strong correlations between steps per day (r = .87) and distance travelled (r = .88) between the Fitbit Zips and iPhones. However, the Fitbit Zip measured significantly more steps per day (mean 8437 vs 7303; P ≤ .001) and greater distances (mean 5.9 vs 4.9; P ≤ .001) than the iPhone. Correlations between the Fitbit Zips and the BARs were moderate for minutes of total (r = .51) and light (r = .40) activity and weak for moderate/fairly active (r = .20) and vigorous/very active (r = .25).ConclusionsThere were strong correlations between the physical activity data measured by Fitbit Zips and iPhones, but the iPhone Health app significantly underestimated the number of steps per day taken and the distance travelled when compared to the Fitbit Zip.So what?Understanding the comparability of accelerometer devices provides useful information for future pragmatic physical activity measurement.
The association between smoking during pregnancy and hypertensive disorders of pregnancy: A systematic review and meta‐analysis
Authors: Wang Jianing , Yang Wenbo , Xiao Wenxuan , Cao Shiyi 
Published: April 2021

AbstractBackgroundSmoking is a major public health problem. However, its association with hypertensive disorders of pregnancy (HDP) is inconclusive.ObjectiveTo find the association between smoking during pregnancy and HDP.Search strategyWe searched PubMed, Ovid and Cochrane Library up to March, 2021, using terms including “smoking” and “HDP”.Selection criteriaObservational studies that assessed the relationship between smoking during pregnancy and HDP were included.Data collection and analysisOdds ratios (OR) and 95% confidence intervals (CI), and other necessary data were extracted. Stata16.0 MP was used to analyze statistics.Main resultsA total of 13 studies were included. Meta‐analysis revealed that smoking during pregnancy was a protective factor for HDP (OR 0.78, 95% CI 0.67–0.92), gestational hypertension (OR 0.74, 95% CI 0.69–0.79), and pre‐eclampsia (OR 0.65, 95% CI 0.58–0.73). Subgroup analysis showed that smoking during pregnancy was a risk factor for HDP in Asia but a protective factor in Europe and North America. Neither quitting smoking before pregnancy nor during pregnancy had a statistically significant association with HDP.ConclusionThis meta‐analysis revealed that smoking during pregnancy might prevent HDP, gestational hypertension, and pre‐eclampsia. Smoking during pregnancy was a risk factor for HDP in Asia but a protective factor in Europe and North America.
Evaluation of multiple reanalyses in reproducing the spatio‐temporal variability of temperature and precipitation indices over southern South America
Authors: Balmaceda‐Huarte Rocio , Olmo Matias Ezequiel , Bettolli Maria Laura , Poggi Maria Mercedes 
Published: April 2021

AbstractSeveral temperature and precipitation indices, with special focus on extremes, were analysed in different sub‐regions of southern South America during 1979–2017 using multiple reanalyses, the CPC gridded data set and the most extended network of meteorological stations employed in regional climate studies up to date. Reanalyses generally well represented the spatial patterns of the indices, although they showed some differences in extreme indices over large portions of southern South America and tended to overestimate precipitation maximums, especially in southern Chile. Furthermore, ERA‐Interim presented clear difficulties in reproducing precipitation near the Andes Mountains, exhibiting the largest overestimations. This seemed to be improved in the new generation of ERA reanalyses (ERA5). When evaluating the long‐term changes, most of the data sets agreed in general warming conditions, stronger and more homogeneous for the maximum temperature. NCEP1 and NCEP2 reanalyses showed contrary temporal changes in almost all the temperature indices. Precipitation indices exhibited less consistent changes among reanalyses, although significant upward trends were detected for precipitation extremes in southeastern South America and downward trends were detected in southern Chile in the observational data sets. In addition, most of the data sets agreed in drier conditions in the arid diagonal region of Argentina as reflected by significant positive trends for dry spells and negative trends for the total annual precipitation. In terms of the inter‐annual correspondence, reanalyses usually presented good correlations to the stations reference in the regional averaged series, mainly for temperature indices and more variable for precipitation indices. Overall, no reanalysis was found to perform best. The use of reanalyses data to perform regional climate studies should consider the existent differences among them and with observational data. Moreover, using multiple sources of information is strongly recommended to account for observational uncertainty, especially in regions like southern South America, where data availability and its resolution are often limited.
Weight Gain and Severe Obstructive Sleep Apnea in Adolescents with Down Syndrome
Authors: Manuel Rachel , Shah Gopi B. , Mitchell Ron B. , Johnson Romaine F. 
Published: April 2021

Objectives/HypothesisTo determine whether the severity of obstructive sleep apnea (OSA) is affected by weight gain velocity (WGV) in adolescents with Down syndrome.Study DesignRetrospective case series.MethodsWe performed a retrospective case series of children with Down syndrome, aged 9–19, referred for polysomnography (PSG) due to suspected OSA at an academic children's hospital. We determined the velocity (slope of change) of yearly weight gain using a mixed effect linear regression model. Subsequently, we determined if velocity of yearly weight gain was greater in adolescents with severe OSA (apnea‐hypopnea index > 10). Significance was set at P < .05.ResultsA total of 77 adolescents with Down syndrome were identified. The average age was 12.5 years (standard deviation = 3.1); 44 (57%) were male and 46 (60%) were Hispanic. The majority, 51 (66%) had severe OSA. The velocity of yearly weight gain prior to PSG in Down syndrome adolescents was similar regardless of OSA severity (mean diff in weight gain at PSG between severe and nonsevere OSA = −1.42, 95% confidence interval = −5.8 to 2.9, P = .52). Down syndrome adolescents with severe OSA weighed more at PSG (58.4 kg vs. 40.9 kg, P < .001) and all years prior to PSG. These findings remained even when controlling for age at PSG.ConclusionsSevere OSA in adolescents with Down syndrome is associated with weight. There was no significant difference in WGV in children with Down syndrome with or without severe OSA.Level of Evidence3 Laryngoscope, 131:2598–2602, 2021
Optimization of Physical and Mechanical Properties of an Active Film of PLA/EEP by a Full Factorial Design
Authors: Nacera Chibani , Nadjet Ardjoum , Hocine Djidjelli , Boukerrou Amar 
Published: April 2021

AbstractThe objective of this work is to develop an active food packaging material based on poly (lactic acid) and ethanolic extracts propolis. Poly(lactic acid)/ethanolic extract propolis films are prepared by casting, using a three level full factorial design that allowed to study the parameters influencing Young's modulus and water absorption. Many experiments are carried out, with a suitable choice of two variables, leading to a mathematical model in the form of a first degree polynomial. The films are subjected to several analyzes: physical and mechanical properties and antibacterial activity. The results show that the optimal film is obtained with an amount of 14% w/w of ethanolic extracts propolis, giving an antimicrobial food packaging material with the following characteristics: amount of propolis extract: 0.14 g, Young's modulus: 1594.16 N mm−2, water absorption rate: 3%, breaking stress: 29.45% and elongation at break: 39.27%.
Rubber Composites Able to Efficiently Shield the Electromagnetic Radiation
Authors: Kvasničáková Andrea , Kruželák Ján , Hložeková Klaudia , Dosoudil Rastislav , Hudec Ivan 
Published: April 2021

AbstractManganese‐zinc ferrite is incorporated into natural rubber in order to prepare rubber magnetic composites. The main goal of the work is to investigate the influence of content of magnetic soft ferrite on physical–mechanical and electromagnetic shielding properties of magnetic composites. The results reveal that the tested composites are able to efficiently shield the electromagnetic radiation by absorption mechanisms. All composites containing 200 phr or more filler exhibit sufficient absorption shielding. On the other hand, the strength characteristics of the composites decreases with increasing content of ferrite.
Combinatorial Bees Algorithm for Vehicle Routing Problem
Authors: Ismail Asrul Harun , Hartono Natalia , Zeybek Sultan , Caterino Mario , Jiang Kaiwen 
Published: April 2021

AbstractVehicle routing problem (VRP) is a combinatorial optimization problem that has been studied intensively for years. Although VRP can be solved using an exact method for small instances, a more complex one will be impractical due to the nature of the problem as an NP‐hard problem. A metaheuristic is more suitable to solve this kind of problem because the near‐optimal solution can be found in a relatively shorter time compared to the exact algorithm. Bees Algorithm (BA) as nature‐inspired metaheuristic is used to find a near‐optimal solution of VRP‐TSPLIB's datasets. This study aims to provide the results of BA on the standard dataset of VRP. The BA has a very good performance, with 3.9% of the average Best‐Error and 1.2 million of the average evaluations to reach the solution.
Thermal Insulation Capacity of a 3D Printed Material
Authors: Mihalache Andrei , Hriţuc Adelina , Boca Marius , Oroian Bogdan , Condrea Ionuţ , Botezatu Carmen , Slătineanu Laurenţiu 
Published: April 2021

AbstractThe 3D printing process allows obtaining parts with different interior structures and made of different materials. Such parts can be used to avoid overheating of various objects under the action of thermal radiation. The existence of different internal structures of the parts, as well as the 3D printing conditions and the distinct physical properties of the materials used, determine a different behavior of the parts in terms of their thermal insulation capacity. To obtain an image of the thermal conductivity of thin parallelepiped‐shaped parts achieved by 3D printing, experimental research is conceived and materialized. The experiments involve the use of an infrared heat source, respectively, measurement of temperature on the surface opposite to that exposed to thermal radiation. The obtained results are mathematically processed to obtain empirical mathematical models that would highlight 3D printed parts' ability to be used as thermal insulating materials.
Aircraft Maintenance: Structural Health Monitoring Influence on Costs and Practices
Authors: Manco Pasquale , Caterino Mario , Macchiaroli Roberto , Rinaldi Marta , Fera Marcello 
Published: April 2021

AbstractThe structural health monitoring (SHM) represents an evolution of the traditional way to design and maintain mechanical structures. SHM systems allow to continuously (or discretely) monitor the structural integrity of an asset, not waiting for the planned check. This result implies an important reduction of inspection time and guarantees an improvement of service life cost of the structural components, but how and how much this cost can be influenced is still an open issue. This research addresses the identification of previous studies that dealt with this topic. A systematic literature review (SLR) is carried out with the aim of investigating the current SHM state‐of‐the art in the aircraft industry in order to point out the main advantages deriving from the application of these technologies and the existing gaps and limitations. Three database (Scopus, Web of science and Google Scholar) are used for selecting peer‐reviewed papers that address with evidence the changes in maintenance practices resulting from the use of SHM. The analysis proves the differences between the traditional programmed maintenance and the innovative predictive approach based on SHM information in terms of interval inspection policy and costs. Moreover, the technical limits that do not allow to totally exploit the potential strength of SHM are outlined.
About the Mechanical Properties for a Type of Green Composites with Hybrid Dammar/Sandarac Matrix and Natural Reinforcements
Authors: Miriţoiu Cosmin Mihai , Stănescu Marius Marinel , Bolcu Dumitru , Jiga Gabriel , Rădoi Alexandru Ioan , Tudose Daniela Ioana 
Published: April 2021

AbstractThis paper presents the mechanical properties for sandwich core strips with a 60% sandarac combination core and 40% Resoltech 1050 epoxy resin with 1055 hardener, and the upper and lower layers reinforced with cotton, silk and linen fabric, and the matrix is a combination of 60% dammar resin and 40% Resoltech 1050 epoxy resin with 1055 hardener. For these materials, there is determined: static mechanical properties from tensile stress (Young elastic modulus, yield strength, breaking strength) and chemical composition by energy dispersive spectroscopy analysis with an scanning electron microscope. It is observed that the dammar resin, in all the cases, has increased mechanical characteristics compared to sandarac. Also, the samples reinforced with cotton show better mechanical properties compared to the ones reinforced with flax and silk.
Salinity Optical Sensor Based on Surface Plasmon Resonance Structure with As2S3 Waveguide
Authors: Miclos Sorin , Popescu Aurelian , Savastru Dan , Baschir Laurentiu 
Published: April 2021

AbstractThe surface plasmonic resonance (SPR) structure consisting of a gold film and amorphous chalcogenide film deposited on the base of a prism is analyzed. The chalcogenide amorphous film with high refractive index, like As2S3, forms plasmonic waveguide, which can maintain several modes of the electromagnetic field. The sensitivity of optical sensor based on SPR for measuring the salinity of aqueous salt solutions is studied numerically. A rutile TiO2 prism that couples the light with plasmons is considered. The considered wavelength is 1550 nm, which is proper for use in the infrared fiber optic networks. The calculations show that the resonance angle depends on the salt concentration and that the shift is enough to resolve salinity of different concentrations.