Semiconductors are the basis of many vital technologies such as electronics, computing, communications, optoelectronics, and sensing. Modern semiconductor technology can trace its origins to the ...invention of the point contact transistor in 1947. This demonstration paved the way for the development of discrete and integrated semiconductor devices and circuits that has helped to build a modern society where semiconductors are ubiquitous components of everyday life. A key property that determines the semiconductor electrical and optical properties is the bandgap. Beyond graphene, recently discovered two-dimensional (2D) materials possess semiconducting bandgaps ranging from the terahertz and mid-infrared in bilayer graphene and black phosphorus, visible in transition metal dichalcogenides, to the ultraviolet in hexagonal boron nitride. In particular, these 2D materials were demonstrated to exhibit highly tunable bandgaps, achieved via the control of layers number, heterostructuring, strain engineering, chemical doping, alloying, intercalation, substrate engineering, as well as an external electric field. We provide a review of the basic physical principles of these various techniques on the engineering of quasi-particle and optical bandgaps, their bandgap tunability, potentials and limitations in practical realization in future 2D device technologies.
Xanthomonas phaseoli pv. manihotis (Xpm) and X. cassavae (Xc) are two bacterial pathogens attacking cassava. Cassava bacterial blight (CBB) is a systemic disease caused by Xpm, which might have ...dramatic effects on plant growth and crop production. Cassava bacterial necrosis is a nonvascular disease caused by Xc with foliar symptoms similar to CBB, but its impacts on the plant vigour and the crop are limited. In this review, we describe the epidemiology and ecology of the two pathogens, the impacts and management of the diseases, and the main research achievements for each pathosystem. Because Xc data are sparse, our main focus is on Xpm and CBB.
This pathogen profile describes the hallmarks of the Xanthomonas phaseoli pv. manihotis–cassava pathosystem and compiles the available data for the nonvascular cassava pathogen Xanthomonas cassavae.
This study investigates the role of NLRP3 inflammasome and its main effector Caspase-1 in inflammation and alveolar bone resorption associated with periodontitis. Heat-killed Aggregatibacter ...actinomycetemcomitans (Aa) was injected 3x/week (4 weeks) into gingival tissues of wild-type (WT), Nlrp3-KO and Caspase1-KO mice. Bone resorption was measured by µCT and osteoclast number was determined by tartrate-resistant acid phosphatase (TRAP) staining. Inflammation was assessed histologically (H/E staining and immunofluorescence of CD45 and Ly6G). In vitro studies determined the influence of Nlrp3 and Caspase-1 in Rankl-induced osteoclast differentiation and activity and on LPS-induced expression of inflammation-associated genes. Bone resorption was significantly reduced in Casp1-KO but not in Nlrp3-KO mice. Casp1-KO mice had increased in osteoclast numbers, whereas the inflammatory infiltrate or on gene expression were similar to those of WT and Nlrp3-KO mice. Strikingly, osteoclasts differentiated from Nlrp3-deficient macrophages had increased resorbing activity in vitro. LPS-induced expression of Il-10, Il-12 and Tnf-α was significantly reduced in Nlrp3- and Casp1-deficient macrophages. As an inceptive study, these results suggest that Nlrp3 inflammasome does not play a significant role in inflammation and bone resorption in vivo and that Caspase-1 has a pro-resorptive role in experimental periodontal disease.
•Curcumin-containing proliposomes can be produced by coating of micronized sucrose.•Nonpurified phospholipids are suitable to produce proliposomes.•Curcumin was efficiently protected when ...encapsulated in liposome dispersions.•Amount of nonpurified phospholipids had a crucial role on liposome stability.•Mixed curcumin-loaded vesicles remained stable for a short storage time.
The feasibility of producing proliposomes containing curcumin, as well as liposome dispersions, using different mixtures of purified and nonpurified soybean phospholipids was studied. Proliposomes were produced through coating of micronized sucrose and physicochemically characterized over 30 days of storage. In addition, the possible interactions among the components were investigated using X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The proliposomes demonstrated a low propensity of water adsorption and low hygroscopicity. In addition, the curcumin content retained in the powders ranged from 67 to 92%. The liposomes were produced following proliposome hydration. Atomic force microscopy indicated the vesicles presented spherical shapes and photon correlation spectroscopy detected that their hydrodynamic diameters ranged from 207 to 222 nm. Finally, the curcumin-loaded liposomes preserved up to 63% of the bioactive compound but remained stable for only 15 days of storage.
We calculate the excitonic spectrum of few-layer black phosphorus by direct diagonalization of the effective mass Hamiltonian in the presence of an applied in-plane electric field. The strong ...attractive interaction between electrons and holes in this system allows one to investigate the Stark effect up to very high ionizing fields, including also the excited states. Our results show that the band anisotropy in black phosphorus becomes evident in the direction-dependent field-induced polarizability of the exciton.
In-depth characterization of fundamental folding steps of small model peptides is crucial for a better understanding of the folding mechanisms of more complex biomacromolecules. We have previously ...reported on the folding/unfolding kinetics of a model α-helix. Here, we study folding transitions in chignolin (GYDPETGTWG), a short β-hairpin peptide previously used as a model to study conformational changes in β-sheet proteins. Although previously suggested, until now, the role of the Tyr2–Trp9 interaction in the folding mechanism of chignolin was not clear. In the present work, pH-dependent conformational changes of chignolin were characterized by circular dichroism (CD), nuclear magnetic resonance (NMR), ultrafast pH-jump coupled with time-resolved photoacoustic calorimetry (TR-PAC), and molecular dynamics (MD) simulations. Taken together, our results present a comprehensive view of chignolin's folding kinetics upon local pH changes and the role of the Tyr2–Trp9 interaction in the folding process. CD data show that chignolin's β-hairpin formation displays a pH-dependent skew bell-shaped curve, with a maximum close to pH 6, and a large decrease in β-sheet content at alkaline pH. The β-hairpin structure is mainly stabilized by aromatic interactions between Tyr2 and Trp9 and CH−π interactions between Tyr2 and Pro4. Unfolding of chignolin at high pH demonstrates that protonation of Tyr2 is essential for the stability of the β-hairpin. Refolding studies were triggered by laser-induced pH-jumps and detected by TR-PAC. The refolding of chignolin from high pH, mainly due to the protonation of Tyr2, is characterized by a volume expansion (10.4 mL mol–1), independent of peptide concentration, in the microsecond time range (lifetime of 1.15 μs). At high pH, the presence of the deprotonated hydroxyl (tyrosinate) hinders the formation of the aromatic interaction between Tyr2 and Trp9 resulting in a more disorganized and dynamic tridimensional structure of the peptide. This was also confirmed by comparing MD simulations of chignolin under conditions mimicking neutral and high pH.
In 2019, the Coronavirus (SARS-CoV-2) virus was identified, also defined as novel coronavirus or severe acute respiratory syndrome coronavirus 2. The Corona VIrus Disease (COVID-19) pandemic ...generated several changes in society in 2020 as a result of its rapid spread in humans. The main symptoms are high fever (greater than or equal to 37.8 degreesC), dry cough, dyspnea, upper respiratory symptoms, myalgia, fatigue and diarrhea in the most uncommon cases. Considering the emergency situation caused by the COVID-19 pandemic and the effects attributed to it, rehabilitation professionals have a fundamental role in the functional recovery of patients, independence and improvement of quality of life. This is a systematic review of the literature, with the aim of discussing the main findings on physical therapy management in functional changes in post-COVID-19 patients. Pubmed, Scielo, Sciencedirect, BVS and PEDro databases were used. The terms MESH/DECs used for the searches were: Rehabilitation, Physical Therapy Modalities, Covid-19, Post-acute Syndromes COVID-19 and Physical Fitness, the keywords were also used: rehabilitation, physiotherapy, Covid-19, post- acute syndrome COVID-19 and functional capacity. To cross the terms, Boolean operators (AND and OR) were used. Randomized trials, recommendations, quasi-randomized or prospective controlled trials, reports, guidelines, and field updates were included. As for the selected population, studies were included in individuals of both sexes, with no age restriction, that evaluated physiotherapeutic interventions in patients who had COVID-19. Literature reviews, case studies, conferences, abstracts of articles published in conference proceedings and letters to the editor were excluded from the research. To measure methodological quality, the PEDro scale was used.Searches for articles were performed restricting the period of publication between the years 2019 to 2022. The electronic search strategy identified a total of 364 records from the selected databases. After screening for duplicates, 14 articles were excluded, followed by screening by titles and abstracts, another 298 articles were excluded, of these 47 potentially relevant records were submitted to full text review and of these 5 randomized clinical trials were included in this review. In view of the findings of this study, it can be concluded that physical therapy rehabilitation should continue after hospital discharge, with the aim of improving physical performance and activities of daily living (ADL) in post-COVID-19 patients.
The epithelial cell adhesion molecule (EpCAM) is an integral transmembrane protein that is frequently overexpressed in embryonic stem cells, tissue progenitors, carcinomas and cancer-initiating ...cells. In cancer cells, expression of EpCAM is associated with enhanced proliferation and upregulation of target genes including c-myc. However, the exact molecular mechanisms underlying the observed EpCAM-dependent cell proliferation remained unexplored. Here, we show that EpCAM directly affects cell cycle progression via its capacity to regulate the expression of cyclin D1 at the transcriptional level and depending on the direct interaction partner FHL2 (four-and-a-half LIM domains protein 2). As a result, downstream events such as phosphorylation of the retinoblastoma protein (Rb) and expression of cyclins E and A are similarly affected. In vivo, EpCAM expression strength and pattern are both positively correlated with the proliferation marker Ki67, high expression and nuclear localisation of cyclin D1, and Rb phosphorylation. Thus, EpCAM enhances cell cycle progression via the classical cyclin-regulated pathway.
Ketoprofen (KTF) and ketorolac (KTL) are among the most primarily used non-steroidal anti-inflammatory drugs (NSAIDs) in humans to alleviate moderate pain and to treat inflammation. Their binding ...affinity with albumin (the main globular protein responsible for the biodistribution of drugs in the bloodstream) was previously determined by spectroscopy without considering some conventional pitfalls. Thus, the present work updates the biophysical characterization of the interactions of HSA:KTF and HSA:KTL by 1H saturation-transfer difference nuclear magnetic resonance (1H STD-NMR), ultraviolet (UV) absorption, circular dichroism (CD), steady-state, and time-resolved fluorescence spectroscopies combined with in silico calculations. The binding of HSA:NSAIDs is spontaneous, endothermic, and entropically driven, leading to a conformational rearrangement of HSA with a slight decrease in the α-helix content (7.1% to 7.6%). The predominance of the static quenching mechanism (ground-state association) was identified. Thus, both Stern–Volmer quenching constant (KSV) and binding constant (Kb) values enabled the determination of the binding affinity. In this sense, the KSV and Kb values were found in the order of 104 M−1 at human body temperature, indicating moderate binding affinity with differences in the range of 0.7- and 3.4-fold between KTF and KTL, which agree with the previously reported experimental pharmacokinetic profile. According to 1H STD-NMR data combined with in silico calculations, the aromatic groups in relation to the aliphatic moiety of the drugs interact preferentially with HSA into subdomain IIIA (site II) and are stabilized by interactions via hydrogen bonding and hydrophobic forces. In general, the data obtained in this study have been revised and updated in comparison to those previously reported by other authors who did not account for inner filter corrections, spectral backgrounds, or the identification of the primary mathematical approach for determining the binding affinity of HSA:KTF and HSA:KTL.
Evolutionary radiations on oceanic islands have fascinated biologists since Darwin’s exploration of the Galápagos archipelago 1, 2. Island radiations can provide key insights for understanding rapid ...speciation, including evolutionary patterns and the processes behind them. However, lack of resolution of species relationships has historically hindered their investigation, particularly in the plant kingdom 3–5. Here, we report a time-calibrated phylogenomic analysis based on genotyping-by-sequencing data 6 of the 15 species of Scalesia (Darwin’s giant daisies), an iconic and understudied plant radiation endemic to the Galápagos Islands and considered the plant counterpart to Darwin’s finches 1, 7–9. Results support a Pliocene to early Pleistocene divergence between Scalesia and the closest South American relatives, and rapid diversification of extant Scalesia species from a common ancestor dated to the Middle Pleistocene. Major evolutionary patterns in Scalesia include the following: (1) lack of compliance with the “progression rule” hypothesis, in which earlier diverging lineages are expected to occupy older islands; (2) a predominance of within-island speciation over between-island speciation; and (3) repeated convergent evolution of potentially adaptive traits and habitat preferences on different islands during the course of diversification. Massive sequencing provided the essential framework for investigating evolutionary and ecological processes in the complex natural laboratory of the Galápagos, thereby advancing our understanding of island plant radiations.
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•Scalesia is an iconic plant radiation in the Galápagos Islands•The 15 species diversified in the Pleistocene, after emergence of most islands•Speciation within islands was more frequent than between islands•Convergent evolution of morphology and habitat preferences was prevalent
Fernández-Mazuecos et al. use phylogenomic tools to investigate the radiation of Scalesia (“Darwin’s finches of the plant world”) in the natural laboratory of the Galápagos Islands. By reconstructing diversification of the 15 species in space and time, they shed light on evolutionary patterns and processes in island plant radiations.
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