Structure and Dynamics in Mg2+-Stabilized γ-Na3PO4.

In parallel with advances in the synthesis of solid-state ionic conductors, there is a need to understand the underlying mechanisms behind their improved ionic conductivities. This can be achieved by obtaining an atomic level picture of the interplay between the structure of materials and the resultant ionic diffusion processes. To this end, the structure and dynamics of Mg2+-stabilized rotor phase material γ-Na3PO4, characterized by neutron scattering, are detailed in this work. The Mg2+-stabilized rotor phase is found to be thermally stable from 4 to 650 K. However, signatures of orientational disorder of the phosphate anions are also evident in the average structure. Long-range Na+ self-diffusion was probed by quasi-elastic neutron scattering and subsequently modeled via a jump diffusion matrix with consideration of the phosphate anion rotations. The resultant diffusion model points directly to coupled anion-cation dynamics. Our approach highlights the importance of considering the whole system when developing an atomic level picture of structure and dynamics, which is critical in the rational design and optimization of energy materials.

Direct Observation of the Mutual Coupling Effect in the Protein-Water-Glycerol Mixture by Combining Neutron Scattering and Selective Deuteration.

Numerous studies have discussed the impact of cosolvents on the structure, dynamics, and stability of proteins in aqueous solutions. However, the dynamics of cosolvents in the protein-water-cosolvent ternary system is largely unexplored in experiments due to technical difficulty. Consequently, a comprehensive understanding of the interplay among proteins, water, and cosolvents is still lacking. Here, we employed selective deuteration and neutron scattering techniques to characterize the individual motions of each component in the protein/water/glycerol (GLY) mixture across various temperatures. The consistent dynamic onset temperatures and the correlation between the MSD of the protein and the viscosity of solvents revealed the mutual coupling effects among the three components. Furthermore, our experimental and simulation results showed that the hydrogen bond relaxation energy barrier in the ternary system is ∼43 kJ/mol, whereas in the protein-water binary system it is merely ∼35 kJ/mol. Therefore, we suggest that GLY can enhance hydrogen bond interactions in the ternary system through the mutual coupling effect, thereby serving as one of the protective mechanisms of protein preservation by GLY.

Colossal electrocaloric effect in an interface-augmented ferroelectric polymer.

The electrocaloric effect demands the maximized degree of freedom (DOF) of polar domains and the lowest energy barrier to facilitate the transition of polarization. However, optimization of the DOF and energy barrier-including domain size, crystallinity, multiconformation coexistence, polar correlation, and other factors in bulk ferroelectrics-has reached a limit. We used organic crystal dimethylhexynediol (DMHD) as a three-dimensional sacrificial master to assemble polar conformations at the heterogeneous interface in poly(vinylidene fluoride)-based terpolymer. DMHD was evaporated, and the epitaxy-like process induced an ultrafinely distributed, multiconformation-coexisting polar interface exhibiting a giant conformational entropy. Under a low electric field, the interface-augmented terpolymer had a high entropy change of 100 J/(kg·K). This interface polarization strategy is generally applicable to dielectric capacitors, supercapacitors, and other related applications.

Proteome-wide 3D structure prediction provides insights into the ancestral metabolism of ancient archaea and bacteria.

Ancestral metabolism has remained controversial due to a lack of evidence beyond sequence-based reconstructions. Although prebiotic chemists have provided hints that metabolism might originate from non-enzymatic protometabolic pathways, gaps between ancestral reconstruction and prebiotic processes mean there is much that is still unknown. Here, we apply proteome-wide 3D structure predictions and comparisons to investigate ancestorial metabolism of ancient bacteria and archaea, to provide information beyond sequence as a bridge to the prebiotic processes. We compare representative bacterial and archaeal strains, which reveal surprisingly similar physiological and metabolic characteristics via microbiological and biophysical experiments. Pairwise comparison of protein structures identify the conserved metabolic modules in bacteria and archaea, despite interference from overly variable sequences. The conserved modules (for example, middle of glycolysis, partial TCA, proton/sulfur respiration, building block biosynthesis) constitute the basic functions that possibly existed in the archaeal-bacterial common ancestor, which are remarkably consistent with the experimentally confirmed protometabolic pathways. These structure-based findings provide a new perspective to reconstructing the ancestral metabolism and understanding its origin, which suggests high-throughput protein 3D structure prediction is a promising approach, deserving broader application in future ancestral exploration.

Investigations of structural and dynamical mechanisms of ice formation regulated by graphene oxide nanosheets.

Recent research indicates that graphene oxide (GO) nanosheets can be used to regulate ice formation by controlling critical ice nucleus growth in water at supercooling temperatures. In addition, the study of ice formation mechanisms regulated by GO nanosheets, a good model system for antifreeze proteins (AFPs), will shed light on how AFPs regulate ice formation in nature. In this work, time-resolved small-angle x-ray scattering (TR-SAXS) and quasi-elastic neutron scattering (QENS) experiments were carried out to investigate the structural and dynamical mechanisms of ice formation regulated by GO nanosheets. Strikingly, a transient intermediate state was observed in TR-SAXS experiments that only exists in the aqueous dispersions with a larger GO size (11 nm). This serves as evidence that the size of GO is critical for regulating ice formation. Elastic neutron scattering results indicate that ice is formed in all samples and thermal hysteresis occurs in GO aqueous dispersions in both H2O and D2O. The structural and dynamics information about water molecules in GO, extracted from QENS, reveals different dynamical behaviors of water molecules in GO aqueous dispersions when approaching the ice formation temperature.

Large intraoral spindle cell lipoma.

Lipomas are relatively common benign neoplasms composed by mature fat cells. Apart from conventional lipomas, several other subtypes have been described in the oral cavity, including fibrolipoma, myxoid lipoma, angiolipoma, myolipoma, chondrolipoma, osteolipoma and spindle cell lipoma (SCL). Intraoral SCL is rare, representing from 1.4% to 9.8% of all intraoral lipomas. The aim of the present study is to report a case of a large intraoral SCL of the buccal mucosa affecting a 46-year-old male, calling attention to its clinical and histological features and to its successfull surgical conservative management. Key words:Lipoma, spindle cell, oral, buccal mucosa.

Accurate Image-guided (Re)Placement of NIRS Probes.

BACKGROUND AND OBJECTIVE: Functional near-infrared spectroscopy (fNIRS) has become an attractive choice to neuroscience because of its high temporal resolution, ease of use, non-invasiveness, and affordability. With the advent of wearable fNIRS technology, on-the-spot studies of brain function have become viable. However, the lack of within-subject reproducibility is one of the barriers to the full acceptability of fNIRS. To support the validation of the claim that within-subject reproducibility of fNIRS could benefit from accurate anatomical information, we present in this paper a method to develop an image-based system that improves the placement of the sensors on the scalp at interactive rates. METHODS: The proposed solution consists of an electromagnetic digitizer and an interactive visualization system that allows monitoring the movements of the digitizer on a real head with respect to the underlying cerebral cortical structures. GPU-based volume raycasting rendering is applied to unveil these structures from the corresponding magnetic resonance imaging volume. Scalp and cortical surface are estimated from the scanned volume to improve depth perception. An alignment algorithm between the real and scanned heads is devised to visually feedback the position of the stylus of the digitizer. Off-screen rendering of the depthmaps of the visible surfaces makes spatial positioning of a 2D interaction pointer possible. RESULTS: We evaluated the alignment accuracy using four to eight anatomical landmarks and found seven to be a good compromise between precision and efficiency. Next, we evaluated reproducibility in positioning five arbitrarily chosen points on three volunteers by four operators over five sessions. In every session, seven anatomical landmarks were applied in the alignment of the real and the scanned head. For the same volunteer, one-way analysis of variance (ANOVA) revealed no significant differences within the five points digitized by the same operator over five sessions (α = 0.05). In addition, preliminary study of motor cortex activation by right-hand finger tapping showed the potential of our approach to increase functional fNIRS reproducibility. CONCLUSIONS: Results of experiments suggest that the enhancement of the visualization of the location of the probes on the scalp, relative to the underlying cortical structures, improves reproducibility of fNIRS measurements. As further work, we plan to study the fNIRS reproducibility in other cortical regions and in clinical settings using the proposed system.

Effect of red blood cell shape changes on haemoglobin interactions and dynamics: a neutron scattering study.

By using a combination of experimental neutron scattering techniques, it is possible to obtain a statistical perspective on red blood cell (RBC) shape in suspensions, and the inter-relationship with protein interactions and dynamics inside the confinement of the cell membrane. In this study, we examined the ultrastructure of RBC and protein-protein interactions of haemoglobin (Hb) in them using ultra-small-angle neutron scattering and small-angle neutron scattering (SANS). In addition, we used the neutron backscattering method to access Hb motion on the ns time scale and Å length scale. Quasi-elastic neutron scattering (QENS) experiments were performed to measure diffusive motion of Hb in RBCs and in an RBC lysate. By using QENS, we probed both internal Hb dynamics and global protein diffusion, on the accessible time scale and length scale by QENS. Shape changes of RBCs and variation of intracellular Hb concentration were induced by addition of the Na+-selective ionophore monensin and the K+-selective one, valinomycin. The experimental SANS and QENS results are discussed within the framework of crowded protein solutions, where free motion of Hb is obstructed by mutual interactions.

Integration of Spatial Information Increases Reproducibility in Functional Near-Infrared Spectroscopy.

As functional near-infrared spectroscopy (fNIRS) is developed as a neuroimaging technique and becomes an option to study a variety of populations and tasks, the reproducibility of the fNIRS signal is still subject of debate. By performing test-retest protocols over different functional tasks, several studies agree that the fNIRS signal is reproducible over group analysis, but the inter-subject and within-subject reproducibility is poor. The high variability at the first statistical level is often attributed to global systemic physiology. In the present work, we revisited the reproducibility of the fNIRS signal during a finger-tapping task across multiple sessions on the same and different days. We expanded on previous studies by hypothesizing that the lack of spatial information of the optodes contributes to the low reproducibility in fNIRS, and we incorporated a real-time neuronavigation protocol to provide accurate cortical localization of the optodes. Our proposed approach was validated in 10 healthy volunteers, and our results suggest that the addition of neuronavigation can increase the within-subject reproducibility of the fNIRS data, particularly in the region of interest. Unlike traditional approaches to positioning the optodes, in which low intra-subject reproducibility has been found, we were able to obtain consistent and robust activation of the contralateral primary motor cortex at the intra-subject level using a neuronavigation protocol. Overall, our findings support the hypothesis that at least part of the variability in fNIRS cannot be only attributed to global systemic physiology. The use of neuronavigation to guide probe positioning, as proposed in this work, has impacts to longitudinal protocols performed with fNIRS.

Epidemiological analysis of 736 patients who suffered facial trauma in Brazil / Análisis epidemiológico de 736 pacientes que sufrieron trauma facial en Brasil

The etiology of facial fractures is directly related to the studied country, varying according to the socioeconomic, cultural condition of the population, besides the period of investigation. The objective of the present study is to evaluate the epidemiological characteristics of the prevalence, treatment modalities and complications rates of maxillofacial fractures in a hospital in the state of Espírito Santo, over a period of 5 years. A total of 428 patients presented a facial fracture, with a prevalence of males (436), with a mean age of 40 years. Regarding the number of fractures, 291 individuals suffered fractures only in the fixed skeleton, 97 only in the mandible, and 48 suffered fractures in both fixed and mandibular skeletons. The predominant anatomical site in fixed skeletal fractures was zygomatic complex (56.6 %), orbit (31.9 %) and nose (29.2 %); while in the mandible the condyle (33.8 %), body (17.9 %) and angle (13.1 %). The frequent etiology was falls, physical aggression, sports accidents. Regarding the type of treatment, in fixed skeleton 192 fractures were treated conservatively and 303 by surgery. Already in the mandible, the numbers were 43 and 143, respectively. In addition, 24 patients progressed with some type of complication in one or more operated sites. It is worth mentioning that epidemiological assessments provide important support in the creation of legislation in the attempt to reduce important for the establishment of clinical and research priorities, since risk factors and patterns of presentation can be identified. Accordingly in an attempt to reduce these rates.

La etiología de las fracturas faciales está directamente relacionada con el país estudiado, variando según la condición socioeconómica y cultural de la población, además del período de investigación. El objetivo del presente estudio fue evaluar las características epidemiológicas de la prevalencia, las modalidades de tratamiento y las tasas de complicaciones de las fracturas maxilofaciales en un hospital en el estado de Espírito Santo, durante un período de 5 años. Un total de 428 pacientes presentaron fractura facial, con una prevalencia de varones (436), con una edad media de 40 años. Con respecto al número de fracturas, 291 individuos sufrieron fracturas solo en el esqueleto fijo, 97 solo en la mandíbula y 48 sufrieron fracturas tanto en el esqueleto fijo como en el mandibular. El sitio anatómico predominante en las fracturas esqueléticas fijas fue el complejo cigomático (56,6 %), la órbita (31,9 %) y la nariz (29,2 %); mientras que en la mandíbula el cóndilo (33,8 %), el cuerpo (17,9 %) y el ángulo (13,1 %). La etiología frecuente fue caídas, agresión física, accidentes deportivos. En cuanto al tipo de tratamiento, en el esqueleto fijo se trataron 192 fracturas de forma conservadora y 303 mediante cirugía. Ya en la mandíbula, los números eran 43 y 143, respectivamente. Además, 24 pacientes progresaron con algún tipo de complicación en uno o más sitios operados. Cabe mencionar que las evaluaciones epidemiológicas brindan un apoyo importante en la creación de legislación en estos casos, para establecer prioridades clínicas y de investigación, debido a que se pueden identificar factores de riesgo y patrones de presentación. En consecuencia, en un intento de reducir estas tasas.