OBJECTIVE:We determined whether Gram-negative bacterial molecules are associated with Alzheimer disease (AD) neuropathology given that previous studies demonstrate Gram-negative Escherichia coli ...bacteria can form extracellular amyloid and Gram-negative bacteria have been reported as the predominant bacteria found in normal human brains.
METHODS:Brain samples from gray and white matter were studied from patients with AD (n = 24) and age-matched controls (n = 18). Lipopolysaccharide (LPS) and E coli K99 pili protein were evaluated by Western blots and immunocytochemistry. Human brain samples were assessed for E coli DNA followed by DNA sequencing.
RESULTS:LPS and E coli K99 were detected immunocytochemically in brain parenchyma and vessels in all AD and control brains. K99 levels measured using Western blots were greater in AD compared to control brains (p < 0.01) and K99 was localized to neuron-like cells in AD but not control brains. LPS levels were also greater in AD compared to control brain. LPS colocalized with Aβ1-40/42 in amyloid plaques and with Aβ1-40/42 around vessels in AD brains. DNA sequencing confirmed E coli DNA in human control and AD brains.
CONCLUSIONS:E coli K99 and LPS levels were greater in AD compared to control brains. LPS colocalized with Aβ1-40/42 in amyloid plaques and around vessels in AD brain. The data show that Gram-negative bacterial molecules are associated with AD neuropathology. They are consistent with our LPS-ischemia-hypoxia rat model that produces myelin aggregates that colocalize with Aβ and resemble amyloid-like plaques.
Preclinical imaging studies offer a unique access to the rat brain, allowing investigations that go beyond what is possible in human studies. Unfortunately, these techniques still suffer from a lack ...of dedicated and standardized neuroimaging tools, namely brain templates and descriptive atlases. Here, we present two rat brain MRI templates and their associated gray matter, white matter and cerebrospinal fluid probability maps, generated from ex vivo Formula: see text-weighted images (90 µm isotropic resolution) and in vivo T
-weighted images (150 µm isotropic resolution). In association with these templates, we also provide both anatomical and functional 3D brain atlases, respectively derived from the merging of the Waxholm and Tohoku atlases, and analysis of resting-state functional MRI data. Finally, we propose a complete set of preclinical MRI reference resources, compatible with common neuroimaging software, for the investigation of rat brain structures and functions.
This open access book provides a detailed exploration of the phase behaviour of, and interfacial properties in, complex colloidal mixtures (e.g., clay, milk, blood). Insights into colloids have been ...at the heart of many innovations in different industries. The big question underlying these innovations is how can colloidal systems be formulated and designed towards the desired properties? To do this, the forces between the colloidal particles need to be controlled. Adding depletants (non-adsorbing polymers or small colloids) is key to controlling the attractive interactions. Colloids and the Depletion Interaction provides the qualitative insights and quantitative tools to understand and predict such forces in colloidal dispersions. It offers a concise introduction to the history and fundamentals of the depletion interaction in, and phase behaviour of, colloidal dispersions. Why does adding polymers lead to attractive forces between colloidal particles? What determines the phase stability of multi-component colloidal systems? These include colloid—polymer mixtures, binary colloidal mixtures, and anisotropic particles such as clay platelets, cubes and rod-like viruses. Conceptual explanations are accompanied by experimental and computer simulation results throughout. Illustrations of depletion effects in colloid science, biology and technology demonstrate its wider significance. The concluding outlook provides the scope of challenges and possibilities in this exciting field of science. This second updated and enlarged edition contains 12 Chapters. It is an ideal book for advanced undergraduates and graduate students in physical chemistry, chemical engineering and soft matter physics. Besides providing a fundamental understanding of depletion interactions in colloidal mixtures, it gives background information on colloidal stability and phase behaviour in general. For experienced scientists and engineers working on mixtures of colloids and non-adsorbing (bio)polymers or colloidal particles, this book serves as a reference for understanding depletion interactions in systems of their specific interest.
White matter hyperintensities are frequent on neuroimaging of older people and are a key feature of cerebral small vessel disease. They are commonly attributed to chronic hypoperfusion, although ...whether low cerebral blood flow is cause or effect is unclear. We systematically reviewed studies that assessed cerebral blood flow in small vessel disease patients, performed meta-analysis and sensitivity analysis of potential confounders. Thirty-eight studies (n = 4006) met the inclusion criteria, including four longitudinal and 34 cross-sectional studies. Most cerebral blood flow data were from grey matter. Twenty-four cross-sectional studies (n = 1161) were meta-analysed, showing that cerebral blood flow was lower in subjects with more white matter hyperintensity, globally and in most grey and white matter regions (e.g. mean global cerebral blood flow: standardised mean difference−0.71, 95% CI −1.12, −0.30). These cerebral blood flow differences were attenuated by excluding studies in dementia or that lacked age-matching. Four longitudinal studies (n = 1079) gave differing results, e.g., more baseline white matter hyperintensity predated falling cerebral blood flow (3.9 years, n = 575); cerebral blood flow was low in regions that developed white matter hyperintensity (1.5 years, n = 40). Cerebral blood flow is lower in subjects with more white matter hyperintensity cross-sectionally, but evidence for falling cerebral blood flow predating increasing white matter hyperintensity is conflicting. Future studies should be longitudinal, obtain more white matter data, use better age-correction and stratify by clinical diagnosis.
It has been well-established that single layer MX2 (M = Mo, W and X = S, Se) are direct gap semiconductors with band edges coinciding at the K point in contrast to their indirect gap multilayer ...counterparts. In few-layer MX2, there are two valleys along the Γ–K line with similar energy. There is little understanding on which of the two valleys forms the conduction band minimum (CBM) in this thickness regime. We investigate the conduction band valley structure in few-layer MX2 by examining the temperature-dependent shift of indirect exciton photoluminescence peak. Highly anisotropic thermal expansion of the lattice and the corresponding evolution of the band structure result in a distinct peak shift for indirect transitions involving the K and Λ (midpoint along Γ-K) valleys. We identify the origin of the indirect emission and concurrently determine the relative energy of these valleys.
Covering the most recent literature in the field, with special emphasis on the physical mechanisms behind their rheological behaviour, this book demonstrates the controllability of soft matter ...through an external (magnetic) stimulus.
Managing soil organic matter (SOM) stocks to address global change challenges requires well‐substantiated knowledge of SOM behavior that can be clearly communicated between scientists, management ...practitioners, and policy makers. However, SOM is incredibly complex and requires separation into multiple components with contrasting behavior in order to study and predict its dynamics. Numerous diverse SOM separation schemes are currently used, making cross‐study comparisons difficult and hindering broad‐scale generalizations. Here, we recommend separating SOM into particulate (POM) and mineral‐associated (MAOM) forms, two SOM components that are fundamentally different in terms of their formation, persistence, and functioning. We provide evidence of their highly contrasting physical and chemical properties, mean residence times in soil, and responses to land use change, plant litter inputs, warming, CO2 enrichment, and N fertilization. Conceptualizing SOM into POM versus MAOM is a feasible, well‐supported, and useful framework that will allow scientists to move beyond studies of bulk SOM, but also use a consistent separation scheme across studies. Ultimately, we propose the POM versus MAOM framework as the best way forward to understand and predict broad‐scale SOM dynamics in the context of global change challenges and provide necessary recommendations to managers and policy makers.
Soil organic matter (SOM) is incredibly complex and requires separation into multiple components with contrasting behavior in order to study and predict its dynamics. Particulate (POM) and mineral‐associated (MAOM) organic matter are two SOM components that are fundamentally different in terms of their formation, persistence, and functioning. We provide evidence of their contrasting properties and responses to global change factors, and propose the POM versus MAOM framework as the way forward to understand and predict broad‐scale SOM dynamics in the context of global change challenges and provide necessary recommendations to managers and policy makers.
We implemented a self-consistent, real-space x-ray absorption calculation within the FDMNES code. We performed the self-consistency within several schemes and identified which one is the most ...appropriate. We show a method that allows a rigorous setting of the Fermi level and thus an estimation of the energy cutoff for the identification and elimination of the occupied states. We investigated what are the structures where one can afford performing the self-consistent calculation at a lesser cluster radius than the absorption one. We exemplify the effects of the self-consistency at the K-edge and for several reference cases, including the copper Cu and the rutile TiO(2). We verified the robustness of our procedure on the transitional 3d and 4d elements. Although amelioration can be noticed, the self-consistency performed at the K-edge does not bring a major improvement of the calculated spectra. Taking into consideration a non-self-consistent, non-spherical potential gives better results than a self-consistent muffin-tin approximation calculation.
This open access book introduces the science of the new materials, soft crystals, by showing various interesting examples. Different from conventional hard and stable crystals, the soft crystals ...respond to gentle stimuli such as vapor exposure and rubbing but maintain their structural order. In this book, their exhibition of remarkable visual changes in their shape, color, and luminescence is described. Through the chapters, historical background, recent remarkable developments, and future prospects are described concisely. This book helps readers to understand a new concept of materials that have the characteristics of stimulus-sensitive soft matter and finely controlled crystals and to design novel materials with the characteristics. The English translation of this book from its Japanese language original manuscript was done with the help of artificial intelligence (machine translation by the service DeepL.com). The text has subsequently been revised further by a professional copy editor in order to refine the work stylistically.
We report the structure of methylammonium lead(II) iodide perovskite in mesoporous TiO2, as used in high-performance solar cells. Pair distribution function analysis of X-ray scattering reveals a two ...component nanostructure: one component with medium range crystalline order (30 atom %) and another with only local structural coherence (70 atom %). The nanostructuring correlates with a blueshift of the absorption onset and increases the photoluminescence. Our findings underscore the importance of fully characterizing and controlling the structure for improved solar cell efficiency.
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