Quark Mass Dependence of Heavy Quark Diffusion Coefficient from Lattice QCD.

We present the first study of the quark mass dependence of the heavy quark momentum and spatial diffusion coefficients using lattice QCD with light dynamical quarks corresponding to a pion mass of 320 MeV. We find that, for the temperature range 195 MeV

Reduced graphene oxide influences morphology and thermal properties of silk/cellulose biocomposites.

In recent decades, research into biomaterials such as silk or cellulose has rapidly expanded due to their abundance, low cost, and tunable morphological as well as physicochemical properties. Cellulose is appealing due to its crystalline and amorphous polymorphs while silk is attractive due to its tunable secondary structure formations which is made up of flexible protein fibers. When these two biomacromolecules are mixed, their properties can be modified by changing their material composition and fabrication methodology, e.g., solvent type, coagulation agent, and temperature. Reduced graphene oxide (rGO) can be used to increase molecular interactions and stabilization of natural polymers. In this study, we sought to determine how small amounts of rGO affect the carbohydrate crystallinity and protein secondary structure formation as well as physicochemical properties and how they affect overall ionic conductivity of cellulose-silk composites. Properties of fabricated silk and cellulose composites with and without rGO were investigated using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-Ray Scattering, Differential Scanning Calorimetry, Dielectric Relaxation Spectroscopy, and Thermogravimetric Analysis. Our results show that addition of rGO influenced morphological and thermal properties of cellulose-silk biocomposites, specifically through cellulose crystallinity and silk ß-sheet content which further impacted ionic conductivity.

The Integration of Biopolymer-Based Materials for Energy Storage Applications: A Review.

Biopolymers are an emerging class of novel materials with diverse applications and properties such as superior sustainability and tunability. Here, applications of biopolymers are described in the context of energy storage devices, namely lithium-based batteries, zinc-based batteries, and capacitors. Current demand for energy storage technologies calls for improved energy density, preserved performance overtime, and more sustainable end-of-life behavior. Lithium-based and zinc-based batteries often face anode corrosion from processes such as dendrite formation. Capacitors typically struggle with achieving functional energy density caused by an inability to efficiently charge and discharge. Both classes of energy storage need to be packaged with sustainable materials due to their potential leakages of toxic metals. In this review paper, recent progress in energy applications is described for biocompatible polymers such as silk, keratin, collagen, chitosan, cellulose, and agarose. Fabrication techniques are described for various components of the battery/capacitors including the electrode, electrolyte, and separators with biopolymers. Of these methods, incorporating the porosity found within various biopolymers is commonly used to maximize ion transport in the electrolyte and prevent dendrite formations in lithium-based, zinc-based batteries, and capacitors. Overall, integrating biopolymers in energy storage solutions poses a promising alternative that can theoretically match traditional energy sources while eliminating harmful consequences to the environment.

Obtaining human teeth for dental education: A cross-sectional study to create ethical and transparent processes.

OBJECTIVES: This study explores the practices of obtaining human teeth for teaching and research in Paraguay. The goal of this research is to understand whether the data supports the need to improve ethical training within dental education, including the creation of a human tooth bank (HTB) METHODS: An observational cross-sectional study was conducted. Three semi-structured questionnaires were developed, one for each target population: dental students, dentists in practice, and the general population. The questionnaires were distributed between February and April 2021, using Google Forms RESULTS: The main places where human teeth were obtained by a student are dental clinics, followed by cemeteries. 94% of students and 91% of dentists paid for teeth on at least one occasion. There is a willingness on the part of students and dentists to donate collections of teeth, and among the general population to donate their teeth if they are extracted, for both teaching and research use. Note that, 31% of students and 6% of the population are aware of what an HTB is, at the same time only 16% of dentists know how it functions CONCLUSION: The number of respondents who obtain teeth from cemeteries and who pay for their acquisition is high. Both of these practices raise ethical concerns. The implementation of informed consent for the donation of extracted teeth is practically nil; although there is a positive attitude towards its implementation. Also, there is a lack of knowledge about the role of an HTB; although the population expressed a willingness to donate extracted teeth.

Structural and Morphological Properties of Wool Keratin and Cellulose Biocomposites Fabricated Using Ionic Liquids.

In this study, the structural, thermal, and morphological properties of biocomposite films composed of wool keratin mixed with cellulose and regenerated with ionic liquids and various coagulation agents were characterized and explored. These blended films exhibit different physical and thermal properties based on the polymer ratio and coagulation agent type in the fabrication process. Thus, understanding their structure and molecular interaction will enable an understanding of how the crystallinity of cellulose can be modified in order to understand the formation of protein secondary structures. The thermal, morphological, and physiochemical properties of the biocomposites were investigated by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray scattering. Analysis of the results suggests that both the wool keratin and the cellulose structures can be manipulated during dissolution and regeneration. Specifically, the ß-sheet content in wool keratin increases with the increase of the ethanol solution concentration during the coagulation process; likewise, the cellulose crystallinity increases with the increase of the hydrogen peroxide concentration via coagulation. These findings suggest that the different molecular interactions in a biocomposite can be tuned systematically. This can lead to developments in biomaterial research including advances in natural based electrolyte batteries, as well as implantable bionics for medical research.

Silk-Cellulose Acetate Biocomposite Materials Regenerated from Ionic Liquid.

The novel use of ionic liquid as a solvent for biodegradable and natural organic biomaterials has increasingly sparked interest in the biomedical field. As compared to more volatile traditional solvents that rapidly degrade the protein molecular weight, the capability of polysaccharides and proteins to dissolve seamlessly in ionic liquid and form fine and tunable biomaterials after regeneration is the key interest of this study. Here, a blended system consisting of Bombyx Mori silk fibroin protein and a cellulose derivative, cellulose acetate (CA), in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIMAc) was regenerated and underwent characterization to understand the structure and physical properties of the films. The change in the morphology of the biocomposites (by scanning electron microscope, SEM) and their secondary structure analysis (by Fourier-transform infrared spectroscopy, FTIR) showed that the samples underwent a wavering conformational change on a microscopic level, resulting in strong interactions and changes in their crystalline structures such as the CA crystalline and silk beta-pleated sheets once the different ratios were applied. Differential scanning calorimetry (DSC) results demonstrated that strong molecular interactions were generated between CA and silk chains, providing the blended films lower glass transitions than those of the pure silk or cellulose acetate. All films that were blended had higher thermal stability than the pure cellulose acetate sample but presented gradual changes amongst the changing of ratios, as demonstrated by thermogravimetric analysis (TGA). This study provides the basis for the comprehension of the protein-polysaccharide composites for various biomedical applications.

Protein and Polysaccharide-Based Fiber Materials Generated from Ionic Liquids: A Review.

Natural biomacromolecules such as structural proteins and polysaccharides are composed of the basic building blocks of life: amino acids and carbohydrates. Understanding their molecular structure, self-assembly and interaction in solvents such as ionic liquids (ILs) is critical for unleashing a flora of new materials, revolutionizing the way we fabricate multi-structural and multi-functional systems with tunable physicochemical properties. Ionic liquids are superior to organic solvents because they do not produce unwanted by-products and are considered green substitutes because of their reusability. In addition, they will significantly improve the miscibility of biopolymers with other materials while maintaining the mechanical properties of the biopolymer in the final product. Understanding and controlling the physicochemical properties of biopolymers in ionic liquids matrices will be crucial for progress leading to the ability to fabricate robust multi-level structural 1D fiber materials. It will also help to predict the relationship between fiber conformation and protein secondary structures or carbohydrate crystallinity, thus creating potential applications for cell growth signaling, ionic conductivity, liquid diffusion and thermal conductivity, and several applications in biomedicine and environmental science. This will also enable the regeneration of biopolymer composite fiber materials with useful functionalities and customizable options critical for additive manufacturing. The specific capabilities of these fiber materials have been shown to vary based on their fabrication methods including electrospinning and post-treatments. This review serves to provide basic knowledge of these commonly utilized protein and polysaccharide biopolymers and their fiber fabrication methods from various ionic liquids, as well as the effect of post-treatments on these fiber materials and their applications in biomedical and pharmaceutical research, wound healing, environmental filters and sustainable and green chemistry research.

Urban atmospheric levels of allergenic pollen: comparison of two locations in Salamanca, Central-Western Spain.

In this paper, differences in the pollen levels detected in two parts of Salamanca (a city in central-western Spain) have been revealed using two volumetric samplers. One sampler was located in the city centre and the other in a semi-natural zone. The two sampling devices were separated by a distance of 1.4 km. During the two-year study period, the most abundant allergenic pollen type was Poaceae, with peak values being detected in May. Maximum values were registered between April and June. The values obtained in both zones with regard to pollen seasonality were similar during the peak day, but the abundance of pollen grains detected in the semi-urban was higher, except for Olea pollen type. The atmospheric pollen season was similar in duration, except for some types belonging to the genera Plantago and Urticaceae, which showed divergent values most probably due to the influence of climatic conditions. The meteorological parameter most significantly correlated to pollen concentration was temperature, being negative for winter species and positive for plants preferring warmer climates. In addition, rainfall showed a negative correlation in most cases due to the influence of precipitation on the behaviour of atmospheric airborne pollen.

Protein-Polysaccharide Composite Materials: Fabrication and Applications.

Protein-polysaccharide composites have been known to show a wide range of applications in biomedical and green chemical fields. These composites have been fabricated into a variety of forms, such as films, fibers, particles, and gels, dependent upon their specific applications. Post treatments of these composites, such as enhancing chemical and physical changes, have been shown to favorably alter their structure and properties, allowing for specificity of medical treatments. Protein-polysaccharide composite materials introduce many opportunities to improve biological functions and contemporary technological functions. Current applications involving the replication of artificial tissues in tissue regeneration, wound therapy, effective drug delivery systems, and food colloids have benefited from protein-polysaccharide composite materials. Although there is limited research on the development of protein-polysaccharide composites, studies have proven their effectiveness and advantages amongst multiple fields. This review aims to provide insight on the elements of protein-polysaccharide complexes, how they are formed, and how they can be applied in modern material science and engineering.

Facile treatment to fine-tune cellulose crystals in cellulose-silk biocomposites through hydrogen peroxide.

The modulation of structural fibrous protein and polysaccharide biopolymers for the design of biomaterials is still relatively challenging due to the non-trivial nature of the transformation from a biopolymer's native state to a more usable form. To gain insight into the nature of the molecular interaction between silk and cellulose chains, we characterized the structural, thermal and morphological properties of silk-cellulose biocomposites regenerated from the ionic liquid, 1-ethyl-3-methylimidazolium acetate (EMIMAc), as a function of increasing coagulation agent concentrations. We found that the cellulose crystallinity and crystal size are dependent on the coagulation agent, hydrogen peroxide solution. The interpretation of our results suggests that the selection of a proper coagulator is a critical step for controlling the physicochemical properties of protein-polysaccharide biocomposite materials.

Near-ground effect of height on pollen exposure.

The effect of height on pollen concentration is not well documented and little is known about the near-ground vertical profile of airborne pollen. This is important as most measuring stations are on roofs, but patient exposure is at ground level. Our study used a big data approach to estimate the near-ground vertical profile of pollen concentrations based on a global study of paired stations located at different heights. We analyzed paired sampling stations located at different heights between 1.5 and 50 m above ground level (AGL). This provided pollen data from 59 Hirst-type volumetric traps from 25 different areas, mainly in Europe, but also covering North America and Australia, resulting in about 2,000,000 daily pollen concentrations analyzed. The daily ratio of the amounts of pollen from different heights per location was used, and the values of the lower station were divided by the higher station. The lower station of paired traps recorded more pollen than the higher trap. However, while the effect of height on pollen concentration was clear, it was also limited (average ratio 1.3, range 0.7-2.2). The standard deviation of the pollen ratio was highly variable when the lower station was located close to the ground level (below 10 m AGL). We show that pollen concentrations measured at >10 m are representative for background near-ground levels.

Evaluation of the Implementation of the Healthy Start Program: Findings from the 2016 National Healthy Start Program Survey.

Objectives The Healthy Start Program has taken a community-based approach to improving maternal and child health outcomes among underserved populations for 25 years. Although the program has been evaluated in the past, it has not undergone a national evaluation since it was transformed in 2014. The purpose of this study is to present data from an early component of the latest national evaluation-the 2016 National Healthy Start Program Survey, which includes information describing grantees, the risk profile of participants served, and the scope of services offered to meet participant needs. Methods Ninety-five grantees completed the survey, and responses are reported at the aggregate level. Study analyses are descriptive. Results Grantees reported serving a population with a high-risk profile characterized by chronic medical conditions or risk behaviors. Most grantees conduct comprehensive needs/risk assessments for participants upon program entry, yet service delivery strategies were mixed, with some differences found by geographic region. Grantees provide a core set of services to participants, including case management and health promotion/education, and tend to refer participants to community providers for services that are deemed appropriate during individual risk assessments. While most grantees have protocols in place related to these priority services, participants may not have been universally offered all services across sites. Conclusions for Practice Although grantees often highlight their facilitation of service/care coordination with existing resources, findings suggest potential areas on which to focus strategic efforts to ensure that the Healthy Start Program is successfully bridging gaps in access and utilization of services for underserved communities.

The Role of Reduced Graphene Oxide toward the Self-Assembly of Lignin-Based Biocomposites Fabricated from Ionic Liquids.

Lignin's immiscibility with most polymers along with its unknown association behaviors are major factors that contribute to its disposal and processability for the production of materials. To fully utilize lignin, an improved understanding of its interaction with other materials is needed. In this study, we investigate the morphological and physicochemical properties upon the addition of reduced graphene oxide (rGO) as a function of material composition in a tertiary system comprised of lignin, cellulose and xylan. The main motivation for this work is to understand how the lignin molecule associates and behaves in the presence of other natural macromolecules, as well as with the addition of reduced graphene oxide. The fabricated biocomposites with and without rGO were investigated using Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), Scanning Electron Microscope (SEM) techniques, Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). The results demonstrated that the regenerated films' structural, morphological and thermal character changed as a function of lignin-xylan concentration and upon the addition of rGO. We also observed a dramatic change in the glass transition temperature and topography. Final analysis showed that the addition of rGO prevented the macromolecules to self-assemble through a reduction of π-π aggregations and changes in the cellulose crystallinity.

A Hierarchical Model To Understand the Processing of Polysaccharides/Protein-Based Films in Ionic Liquids.

In recent years, biomaterials from abundant and renewable sources have shown potential in medicine and materials science alike. In this study, we combine theoretical modeling, molecular dynamics simulations, and several experimental techniques to understand the regeneration of cellulose/silk-, chitin/silk-, and chitosan/silk-based biocomposites after dissolution in ionic liquid and regeneration in water. We propose a novel theoretical model that correlates the composite's microscopic structure to its bulk properties. We rely on modeling non-cross-linked biopolymers that present layer-like structures such as ß-sheets and we successfully predict structural, thermal, and mechanical properties of a mixture of these biomolecules. Our model and experiments show that the solubility of the pure substance in the chosen solvent can be used to modulate the amount of crystallinity of the biopolymer blend, as measured by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Thermogravimetric analysis (TGA) shows that the decomposition temperature of the blended biocomposites compared to their pure counterparts is reduced in accordance with our theoretical predictions. The morphology of the material is further characterized through scanning electron microscopy (SEM) and shows differently exposed surface area depending on the blend. Finally, differential scanning calorimetry (DSC) is performed to characterize the residual water content in the material, essential for explaining the regeneration process in water. As a final test of the model, we compare our model's prediction of the Young's modulus with existing data in the literature. The model correctly reproduces experimental trends observed in the Young's modulus due to varying the concentration of silk in the biopolymer blend.

Impact of ionic liquid type on the structure, morphology and properties of silk-cellulose biocomposite materials.

Microcrystalline cellulose and Bombyx mori silk blended biocomposite films were regenerated using various imidazolium-based ionic liquids. The films were characterized to understand the effect of the inter- and intra-molecular interactions upon the morphology and thermal properties. Various techniques were implemented to investigate structural, morphological and thermal properties of the biocomposite films, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray scattering. Results show that the type of ionic liquid has strong influence on the structure of silk-cellulose composites that can form either amorphous or semicrystalline structures. While the thermal properties are independent of the type of cation in ionic liquids, the levels of ß-sheet configuration are dependent on the type of anion, which further causes changes on the biocomposite thermal properties. The topological image provided information to support morphological effects on the varying ionic liquids and X-ray scattering allowed for insight on the role of ionic liquids on the crystallinity and the spacing differences in biocomposite films. The results have demonstrated that there is a direct relationship between the intermolecular interactions in films and the anion structure of the ionic liquids.

Elaborate ultrastructure of the Hirudo (Annelida: Hirudinae) cocoon surface.

Species of medicinal leeches (Hirudo medicinalis, H. verbana, and H. sulukii) secrete hard-shelled cocoons. When initially deposited, a cocoon is surrounded by a foam. Over a short time, the foam is transformed into a three-dimensional structure. We show here that this peripheral structure likely forms by the solidification and dehydration of a moderately viscous, proteinaceous substance that surrounds bubbles of various sizes. The resulting matrix-like structure comprises a network of curved branches juxtaposed at ∼120° and taper in width as a function of distance from the outer cocoon wall. The material is proteinaceous, and traps environmental material in its composition, especially silicon. The geometry of compartments and abundance of silicon on branch surfaces suggest a mechanism for trapping water to prevent desiccation in a terrestrial environment.

Structure-property relationships of Thai silk-microcrystalline cellulose biocomposite materials fabricated from ionic liquid.

Biomaterials made from natural proteins and polysaccharides have become increasingly popular in the biomedical field due to their good biocompatibility and tunable biodegradability. However, the low miscibility of polysaccharides with proteins presents challenges in the creation of protein-polysaccharide composite materials. In this study, neat 1-allyl-3-methylimidazolium chloride (AMIMCl) ionic liquid was used to regenerate Thailand gold Bombyx mori silk and microcrystalline cellulose blended films. This solvent was found to not only effectively dissolve both natural polymers, but also preserve the structure and integrity of the polymers. A single glass transition temperature for each blend was found in DSC curves, indicating good miscibility between the Thai silk and cellulose molecules. The structural composition as well as the morphology and thermal stability of blend films were then determined using FTIR, SEM and TGA. It was found that by varying the ratio of Thai silk to cellulose, the thermal and physical properties of the material could be tuned. Blended films tended to be more thermally stable which could be due to the presence of hydrophobic-hydrophobic or electrostatic interactions between the silk and cellulose. These studies offered a new pathway to understand the tunable properties of protein-polysaccharide composite biomaterials with controllable physical and biological properties.

Assessing allergenicity in urban parks: A nature-based solution to reduce the impact on public health.

Urban parks play a key role in the provision of ecosystem services, actively participating in improving the quality of life and welfare of local residents. This paper reports on the application of an index designed to quantify the allergenicity of urban parks in a number of Spanish cities. The index, which records biological and biometric parameters for the tree species growing there, classifies parks in terms of the risk they pose for allergy sufferers, graded as null, low, moderate or high. In this initial phase, the index was applied to 26 green areas in 24 Spanish cities; green areas varied in type (urban park, historical or modern garden, boulevard, square or urban forest), size 1-100 ha), geographical location, species richness, number of trees and tree density (number of trees / ha.). The data obtained were used to calculate the percentage of allergenic species in each park, which varied between 17-67%; density ranged from 100 to 300 trees/ha. The index values recorded ranged from a minimum of .07 to a maximum of .87; a significant correlation was found between index value and both number of trees and tree density. Taking an index value of .30 as the threshold considered sufficient to trigger allergy symptoms in the sensitive population, 12 of the parks studied may be regarded as unhealthy at any time of the year. Corrective measures to mitigate the impact of pollen emissions include the implementation of nature-based solutions at various levels: planning and design, handling and management, and strengthening of urban green-infrastructure elements. The index proved to be a useful tool for environmental analysis, and complies with the principles of portability and scalability central to current and horizon scientific research.

Macromolecular Interactions Control Structural and Thermal Properties of Regenerated Tri-Component Blended Films.

With a growing need for sustainable resources research has become highly interested in investigating the structure and physical properties of biomaterials composed of natural macromolecules. In this study, we assessed the structural, morphological, and thermal properties of blended, regenerated films comprised of cellulose, lignin, and hemicellulose (xylan) using the ionic liquid 1-allyl-3-methylimidazolium chloride (AMIMCl). Attenuated total reflectance Fourier transform infrared (ATR-FTIR) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray scattering, and thermogravimetric analysis (TGA) were used to qualitatively and quantitatively measure bonding interactions, morphology, and thermal stability of the regenerated films. The results demonstrated that the regenerated films' structural, morphological, and thermal character changed as a function of lignin-xylan concentration. The decomposition temperature rose according to an increase in lignin content and the surface topography of the regenerated films changed from fibrous to spherical patterns. This suggests that lignin-xylan concentration alters the self-assembly of lignin and the cellulose microfibril development. X-ray scattering confirms the extent of the morphological and molecular changes. Our data reveals that the inter- and intra-molecular interactions with the cellulose crystalline domains, along with the amount of disorder in the system, control the microfibril dimensional characteristics, lignin self-assembly, and possibly the overall material's structural and thermal properties.