bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic Resonance Iron Imaging in Amyotrophic Lateral Sclerosis
Authors: Bhattarai Anjan , Egan Gary F. , Talman Paul , Chua Phyllis , Chen Zhaolin 
Published: February 2021

Amyotrophic lateral sclerosis (ALS) results in progressive impairment of upper and lower motor neurons. Increasing evidence from both in vivo and ex vivo studies suggest that iron accumulation in the motor cortex is a neuropathological hallmark in ALS. An in vivo neuroimaging marker of iron dysregulation in ALS would be useful in disease diagnosis and prognosis. Magnetic resonance imaging (MRI), with its unique capability to generate a variety of soft tissue contrasts, provides opportunities to image iron distribution in the human brain with millimeter to sub‐millimeter anatomical resolution. Conventionally, MRI T1‐weighted, T2‐weighted, and T2*‐weighted images have been used to investigate iron dysregulation in the brain in vivo. Susceptibility weighted imaging has enhanced contrast for para‐magnetic materials that provides superior sensitivity to iron in vivo. Recently, the development of quantitative susceptibility mapping (QSM) has realized the possibility of using quantitative assessments of magnetic susceptibility measures in brain tissues as a surrogate measurement of in vivo brain iron. In this review, we provide an overview of MRI techniques that have been used to investigate iron dysregulation in ALS in vivo. The potential uses, strengths, and limitations of these techniques in clinical trials, disease diagnosis, and prognosis are presented and discussed. We recommend further longitudinal studies with appropriate cohort characterization to validate the efficacy of these techniques. We conclude that quantitative iron assessment using recent advances in MRI including QSM holds great potential to be a sensitive diagnostic and prognostic marker in ALS. The use of multimodal neuroimaging markers in combination with iron imaging may also offer improved sensitivity in ALS diagnosis and prognosis that could make a major contribution to clinical care and treatment trials.Level of Evidence2Technical EfficacyStage 3
Solid‐phase microextraction of methadone by using a chitosan nanocomposite incorporated with Polyoxomolibdate nanocluster/Graphene oxide
Authors: Abedi Hamid 
Published: February 2021

AbstractIn the present study, we report on the simple sol–gel preparation of a nanocomposite composed of chitosan/ polyoxometalate /graphene oxide, and its application in the headspace solid‐phase microextraction combined with the ion mobility spectrometry for the analysis of methadone in biological matrices. The developed nanocomposite was characterized through the infrared spectroscopy and thermogravimetric analyses. The ternary nanocomposite coating offers good mechanical and thermal stability and high extraction efficiency thanks to its large specific surface. A central composite statistical design was used to study the main variables affecting the extraction efficiency. Afterward, to study the relationship between different input and output variables as well as to identify the optimal operating conditions, response surface methodology was used, whereby a second‐order polynomial equation was fit to the experimental data. The optimized extraction conditions were as follows: temperature, 70°C; extraction time, 15 min; and concentration of NaCl, 5%w/v. The detection limit of 0.12 ng/mL was obtained at the optimized extraction conditions, and the calibration plot was linear in the concentration range of 0.30–200 ng/mL. With relatively low limit of detection and good precisions, the proposed method has the potential for the extraction and determination of methadone in biological samples.
Sol‐Gel Synthesis and Antibacterial Characterization of Bioactive Ferrous Citrate‐Silica Hybrid Materials
Authors: Fusco Alessandra , Donnarumma Giovanna , Caputo Pina , Gallo Monica. , Catauro Michelina 
Published: February 2021

AbstractThe aim of this work is the synthesis of therapeutic systems, iron (II) based, by sol‐gel method. In a SiO2 matrix, different weight percentages of ferrous citrate (Fe(II)C are embedded. Fourier Transform Infrared (FTIR) spectroscopy is used to study the interactions among different components in the hybrid materials. The bioactivity of the synthesized hybrid materials is evaluated by the formation of a layer of hydroxyapatite on the surface of samples soaked in SBF using FTIR spectroscopy. Finally, also, the potential antibacterial properties of the different materials against two different bacteria, Staphylococcus epidermidis and Pseudomonas aeruginosa, are investigated.
Kinetics of Formation of Flavano‐C‐Glycosidic Ellagitannins (Acutissimin A and B) in Model Solutions Containing Medium Toasted Oak Chips and Catechin for Wine Aging
Authors: Gallo Monica , Montesano Domenico , Ciaravolo Martina , De Paola Fulvio , Poggetto Giovanni Dal , Naviglio Daniele 
Published: February 2021

AbstractThe aging process of wine goes beyond conservation and involves the use of wood, which is capable of containing and protecting, and allows a limited passage of oxygen, sufficient to promote slow maturation of the wine, thanks to which it reaches the maximum of its organoleptic qualities. The most used wood is oak and during aging, the wine extracts from the wood of the barrels an abundant quantity of aromatic substances, due to the contact between the wine and the matrix of the wood. Among the newly formed compounds, the flavano‐ellagitannins, namely the acutissimin A and B, are the minor compounds found in wood aged wine. They are formed during the aging process through the condensation of tannins, such as vescalagin, extracted from the wood matrix and flavonoids, such as catechins contained in wine. The aim of the study is to verify the formation of acutissimins after 28 days in model solutions that simulated aged wine in the presence of 1%, 5%, and 10% w/v percentages of wood chips obtained from Quercus alba and with variable concentrations of catechin (100 and 500 mg L−1). The formation of compounds, including acutissimin A and B, and the disappearance of catechin are identified by high‐performance liquid chromatography/electrospray ionization/mass spectrometry. Acutissimins A and B are validated by comparison with the characteristic m/z reported in the literature. Based on the results obtained, the model system prepared with 500 mg L−1 of catechin and 10% w/v oak chips showed the highest content of acutissimin A and B.
Chiral Separation of Diastereomeric and Enantiomeric Products Obtained by an Organic Reaction in Aqueous Media between Cyclohexanone and p‐nitrobenzaldehyde by HPLC on Chiral Stationary Phase
Authors: Naviglio Daniele , Poggetto Giovanni Dal , Montesano Domenico , Ciaravolo Martina , De Paola Fulvio , Gallo Monica 
Published: February 2021

AbstractTo understand the intimate essence of the phenomena that occur around us and in us, it is necessary to go down to the atomic and molecular level. From the scale of atoms to the human one, nature is chiral (the term derives from the Greek χείρ, “hand,” that are not superimposable). A chiral chemical compound exists as two isomeric forms, called enantiomers, which are the mirror image of each other and cannot be superimposed on each other. It is important to understand the cause‐effect correlations of this asymmetry, which seems to be universal feature of many natural substances; in fact, many drugs, food additives, flavors, cosmetics, agrochemicals, and so on show chirality and surprisingly the biological activity of the two enantiomers is often different (for example one is biologically active, while the other is not active). To separate enanatiomers, an interaction with an entity that is also chiral with the formation of special interactions is required. This work describes the development of the separation method of four diastereoisomers obtained as products (adducts) of an organic reaction between cyclohexanone and benzaldehyde variously substituted in aromatic ring. The chiral separation of the two geometric isomers syn and anti adducts produced by the reaction is obtained by high performance chromatography with a diode detector (HPLC‐DAD), using a chiral column and a ternary mixture composed of n‐hexane, dichloromethane and ethanol.
Kinetics of the Non‐isothermal Degradation of POSS/EPDM Hybrids Composites
Authors: Zaharescu Traian , Catauro Michelina , Blanco Ignazio 
Published: February 2021

AbstractPolyhedral Oligomeric Silsesquioxane (POSS)/Ethylene‐propylene‐diene monomer (EPDM) composite, at 3% wt of POSS, is prepared by the evaporation of solvent (CHCl3) from polymer/filler system at room temperature and is investigated, by the means of thermogravimetric analysis (TGA), and the obtained TGA data are treated by the Kissinger method to get the apparent activation energy (Ea) of degradation. The results obtained for the composites, at different levels of irradiation, are discussed and compared with each other and with those obtained for pristine EPDM. A good improvement of the thermal stability, with respect to the neat polymer, is found showing the effect of the POSS molecules on the degradation rate. A classification among the samples at different levels of radiations is also drawn up, showing also in this case, the beneficial effect of the POSSs presence.
Structural and Elastic Characterization of Biopolymers Hydrolysis by Acoustic Microscopy
Authors: Morokov Egor , Demina Varvara , Sedush Nikita , Kalinin Kirill , Dmitryakov Petr , Krasheninnikov Sergei , Khramtsova Elena , Grigoriev Timofei , Chvalun Sergei , Levin Vadim 
Published: February 2021

AbstractIn this work, the high‐frequency acoustic microscopy is applied for imaging of internal microstructure and measurement of elastic characteristics of the biodegradable polymers based on D,L‐lactide, L‐lactide, ε‐caprolactone, and their copolymers. Acoustic microscopy results (images of microstructure in the volume and values of sound speed) have been supplemented by data on gel permeation chromatography, differential scanning calorimetry, and mechanical tensile test obtained on the polymers under the hydrolysis range from initial state to 8 weeks with step of 2 weeks. The features of ultrasound visualization and elastic characterization of each the polymer type have been discussed. The changes of the ultrasound characteristics have been detected in the high‐rate degradation polymers.
Organic Inhibitors to Prevent Chloride‐Induced Corrosion in Concrete: Atomistic Simulations of Triethylenetetramine‐Based Inhibitor Film
Authors: Raffaini Giuseppina , Catauro Michelina , Ganazzoli Fabio , Bolzoni Fabio , Ormellese Marco 
Published: February 2021

AbstractInhibitors are largely used to prevent chloride‐induced corrosion in reinforced concrete structures thanks to both a barrier effect on chloride penetration and a competition with the adsorption of the inhibitor. The interaction mechanisms between passive film on carbon steel, the inhibitor molecule, and chlorides still require deeper understanding. Theoretical studies based on molecular mechanics (MM) and molecular dynamics (MD) methods can be useful to better understand the passive film formation and its interaction with chlorides. In this work, the interaction between a triethylenetetramine (TETA) inhibitor film on γ‐FeOOH surface and chlorides is studied using MD methods. After MM optimization in the initial adsorption stage, some chlorides are close to protective TETA film. After MD run at room temperature effectively, chlorides remain close to the protective film. In order to have an effective barrier on chloride attack, the metal oxide must remain wholly covered by the protective film. The TETA film well covers the lepidocrocite surface but cannot kinetically efficiently prevent the chloride‐induced corrosion compared to other organic films exposing COO− groups because it does not exert any repulsion to chlorides.
Research of Impregnated Carbon Fiber Tow Quality for 3D Composites Printing
Authors: Kuncius Tomas , Rimašauskas Marius 
Published: February 2021

AbstractTime nowadays becoming more and more important resource in the life. Additive manufacturing technologies allow to produce very complex shapes of products reducing product development time. Moreover, additive manufacturing of composite parts allows to produce structural parts with perfect mechanical properties. Though production of composites is still very complicated because reinforcement material needs to be prepared for the process. Moreover, preparation process can significantly influence on quality of produced part. This article focusing on preparation procedure of continuous carbon fiber (CCF) tow for 3D printing of composite structures. Visual analysis of impregnated CCF showed that internal air voids area in the analyzed cross‐sections fluctuates from 11.1% to 22.8%. Meanwhile, after pull‐out test, significant effect of impregnation on adhesion is observed. Not impregnated CCF is pulled‐out from matrix material with the tensile force 38 N, however impregnated CCF is not even pulled‐out with the force 138 N.
Investigation of Specific FDM Process Parameters to Optimize the Polymer Discharge of Carbon Fiber Reinforced PEEK
Authors: Wächter Julian , Elsner Christian Lennart , Moritzer Elmar 
Published: February 2021

AbstractFused deposition modeling (FDM) is a widely used manufacturing process and the materials market is growing due to the increased requirements on materials. In particular, processing of high‐temperature materials such as PEEK is challenging. The aim of these studies is to investigate and improve the processability of a carbon fiber reinforced polyether ether ketone (PEEK) material in the FDM process. The first step is to define the relevant process parameters, which remain constant over the entire investigation. In particular, the material‐specific temperatures must be defined. Based on previous investigations regarding the weld seam strength and the warpage of the selected PEEK materials, a method to determine and adjust essential process parameters should be developed. One approach is the consideration of the volumetric polymer discharge at a stationary filament feed rate. The optimized adjustment of the feed rate ensures increased component densities and an improved process reliability. In this context, the component areas with non‐stationary extruder movement, such as in corner areas, have got a huge influence on the component quality. The acceleration and deceleration processes do not result in a desired uniform strand geometry due to the pressure changes within the nozzle. The acceleration can result in thinner strands while the deceleration can lead to a thickening of the polymer discharge. The aim is to adjust the pressure inside the nozzle depending on the acceleration profile to enable a homogenous strand geometry. The method should therefore allow the improvement of the processability of PEEK materials.
Stainless Steel Parts Produced by Fused Deposition Modeling and a Sintering Process Compared to Components Manufactured in Selective Laser Melting
Authors: Schumacher Christian , Moritzer Elmar 
Published: February 2021

AbstractMetal parts can be manufactured in the fused deposition modeling (FDM) process using polymer filaments filled with metal powder. In accordance to the conventional metal injection molding (MIM) process, the FDM process is used to produce green parts. The polymer is removed from these green parts in post‐treatment steps to produce brown parts. Finally, the metal particles of the brown parts are sintered to produce the final components (white parts). During the sintering process, a shrinkage of about 20% occurs in each spatial direction. However, due to the green parts produced in FDM, the shrinkage is influenced by the part orientation on the building platform and the strand deposition strategy. In this publication the BASF 3D Printing Solutions GmbH material Ultrafuse 316L is investigated. This material is a POM (polyoxymethylene) polymer filled with stainless steel (316L) particles which is available in the form of a filament. The investigations focus on the influence of material specific FDM processing parameters and the achievable properties of the white parts. For this purpose, tensile strength tests are carried out. During these investigations, the properties of the green parts are considered in order to produce high‐quality white parts. The density of the green parts is used as an evaluation criterion to directly assess the part quality. Additionally, the possibility of producing partially filled component areas in FDM is being observed.
Further results on modified harmonic functions in three dimensions
Authors: Leutwiler Heinz 
Published: February 2021

The Weinstein equation
, with
, considered in
, is a modification of the classical Laplace equation
. Its solutions are called k‐modified harmonic functions. Whereas for positive integers k the Weinstein equation is relatively well understood, little is known if the parameter k is negative.The main result of this article is the statement that in case the negative integers are even, i.e.,
, we still have a Fischer‐type decomposition. For
, the classical harmonic functions, this decomposition is well known. But also in case
, a Fischer‐type decomposition holds true, a Fischer‐type decomposition holds true. Surprisingly in case
or
and probably in all higher negative odd cases, the decomposition doesn't hold.In case
, we give a complete description of the vector space
of homogeneous k‐modified harmonic polynomials of degree n in
. Such a result is also at hand in case
. Finally, in case
of the classical harmonic functions, we give a description of the vector space
.
A trust‐region method for the parameterized generalized eigenvalue problem with nonsquare matrix pencils
Authors: Li Jiao‐fen , Wang Kai , Liu Yue‐yuan , Duan Xue‐feng , Zhou Xue‐lin 
Published: February 2021

AbstractThe l parameterized generalized eigenvalue problems for the nonsquare matrix pencils, proposed by Chu and Golub [SIAM J. Matrix Anal. Appl., 28(2006), pp. 770‐787], can be formulated as an optimization problem on a corresponding complex product Stiefel manifold. Some early proposed algorithms are based on the first‐order information of the objective function, and fast convergence could not be expected. In this article, we turn the generic Riemannian trust‐region method of Absil et al. into a practical algorithm for solving the underlying problem, which enjoys the global convergence and local superlinear convergence rate. Numerical experiments are provided to illustrate the efficiency of the proposed method. Detailed comparisons with some existing results (l = 1 and l = n) are given first. For the case l = n, the algorithm can yield exactly the same optimal solution as Ito and Murota's algorithm, which is essentially a direct method to solve the problem. The algorithm runs faster than Boutry et al.'s algorithm for the case l = 1. Further comparisons with some early proposed gradient‐based algorithms, and some latest infeasible methods for solving manifold optimization problems are also provided to show the merits of the proposed approach.
Overcoming Disparities in Cancer: A Need for Meaningful Reform for Hispanic and Latino Cancer Survivors
Authors: Kronenfeld Joshua P. , Graves Kristi D. , Penedo Frank J. , Yanez Betina 
Published: February 2021

Abstract

Hispanic and Latino (HL) cancer survivors are at a critical disadvantage compared with non-Hispanic White (NHW) patients regarding sociodemographic adversities and access to equitable treatment options. By 2030, there will be about four million HL cancer survivors in the U.S., representing nearly 20% of survivors in this country. Hispanics and Latinos are subjected to significant challenges in accessing and receiving equitable care relative to NHWs. Hispanics and Latinos also experience lower rates of health insurance and financial resources, limiting health care options. These disparities often originate from disparate social determinants of health, including lower funding for education and school programs, greater neighborhood stressors and violence, lower access to healthy and affordable food, and greater barriers to community health and exercise opportunities. Even among HL cancer survivors with proper access to health care, they experience disparate treatment options, including low inclusion in clinical trials and/or access to experimental therapies. A solution to these barriers necessitates complex and systemic changes that involve, for example, investing in public health programs, increasing the diversity and cultural awareness of the medical workforce, and promoting research opportunities such as clinical trials that are inclusive of HLs. Only through meaningful reform will equitable cancer care be available for all in the U.S. regardless of racial and/or ethnic background. This article reviews some of the critical social determinants of health and biases relevant to HL cancer survivors and provides recommendations for achieving cancer health equity.

Implications for Practice
Hispanics and Latinos experience a significant and often disproportionate cancer-related burden compared with non-Hispanic and Latino White individuals and other racial and ethnic groups. Meaningful reform to achieve health equity in oncology should focus on approaches to gaining trust among diverse patients, cultural and community sensitivity and engagement in oncology care and research, diversifying the workforce, and improving inclusion in clinical trial participation. Taken together, these recommendations can lead to exemplary and equitable care for all patients.
Residue analysis of thermally depolymerized phthalaldehyde‐based polymer thin films
Authors: Engler Anthony , Lo Chi Kin , Kohl Paul A. 
Published: February 2021

AbstractIn this study, thermolysis of poly(phthalaldehyde), pPHA, was investigated, and the nonvolatile residues produced were characterized by bulk and surface analyses to provide insight into its use as a resist material for thermal scanning probe lithography. A temperature of 300°C for a short time was required to remove nearly all of the residue produced from pPHA depolymerization. X‐ray photoelectron spectroscopy (XPS) was used to quantify the trace amount of hydrocarbon residue after thermolysis. Time‐of‐flight secondary ion mass spectrometry (SIMS) results show that the residue is largely PHA monomers and oligomers, but also include hydrocarbon char. Differences in molecular weight and composition of the residue as a function of copolymer composition were investigated to give insight into designing new thermal resist materials.