We present detailed multifrequency resonant Raman measurements of potassium graphite intercalation compounds (GICs). From a well-controlled and consecutive in situ intercalation and high-temperature ...deintercalation approach the response of each stage up to stage VI is identified. The positions of the G and 2D lines as a function of staging depend on the charge transfer from K to the graphite layers and on the lattice expansion. Ab initio calculations of the density and the electronic band structure demonstrate that most (but not all) of the transferred charge remains on the graphene sheets adjacent to the intercalant layers. This leads to an electronic decoupling of these “outer” layers from the ones sandwiched between carbon layers and consequently to a decoupling of the corresponding Raman spectra. Thus, higher stage GICs offer the possibility to measure the vibrations of single, double, and multilayer graphene under conditions of biaxial strain. This strain can additionally be correlated to the in-plane lattice constants of GICs determined by X-ray diffraction. The outcome of this study demonstrates that Raman spectroscopy is a very powerful tool to identify local internal strain in pristine and weakly charged single and few-layer graphene and their composites, yielding even absolute lattice constants.
Although common among bacteria, lateral gene transfer--the movement of genes between distantly related organisms--is thought to occur only rarely between bacteria and multicellular eukaryotes. ...However, the presence of endosymbionts, such as Wolbachia pipientis, within some eukaryotic germlines may facilitate bacterial gene transfers to eukaryotic host genomes. We therefore examined host genomes for evidence of gene transfer events from Wolbachia bacteria to their hosts. We found and confirmed transfers into the genomes of four insect and four nematode species that range from nearly the entire Wolbachia genome (>1 megabase) to short (<500 base pairs) insertions. Potential Wolbachia-to-host transfers were also detected computationally in three additional sequenced insect genomes. We also show that some of these inserted Wolbachia genes are transcribed within eukaryotic cells lacking endosymbionts. Therefore, heritable lateral gene transfer occurs into eukaryotic hosts from their prokaryote symbionts, potentially providing a mechanism for acquisition of new genes and functions.
The impact of vectorial magnetic field effects on electrical conductivity and nonlinear optical transmittance exhibited by multi-wall carbon nanotubes was studied. The samples were synthetized by an ...aerosol pyrolysis processing route in a thin film form. Optical signals in a two-wave mixing configuration allowed us to identify two orthogonal directions of propagation for a magnetic field travelling through the nanomaterials studied. A selective modification in optical absorption was considered to be induced by magnetic perturbations in the sample. Standard optical Kerr gate measurements were carried out for exploring the third order nonlinear optical behavior of the film. A capacitive effect influenced by optical and magnetic excitations was distinguished to be characteristic of the sample. Magneto-quantum conductivity sensitive to the direction of an external magnetic field interacting with the tubes was analyzed. Magnetically-induced changes in electronic band parameters seem to be the main responsible for the optical and electrical modulation observed in the nanostructures. Immediate applications for developing magneto-optical and magneto-electrical functions can be contemplated.
In Polyhydroxyalkanoate (PHA) production processes using Mixed Microbial Culture (MMC), the success of the culture selection step determines, to a great extent, the PHA accumulation performance ...obtained in the final PHA production stage. In this study, the effect of the influent substrate concentration (30–60
Cmmol VFA/L) on the selection of a PHA-storing culture using a complex feedstock, fermented sugar molasses, was assessed. At 30 and 45
Cmmol VFA/L, substrate concentration impacted on the process kinetics through a substrate dependent kinetic limitation effect. However, further increasing the carbon substrate concentration to 60
Cmmol VFA/L, resulted in an unforeseen growth limitation effect associated with a micronutrient deficiency of the fermented feedstock (magnesium) and high operating pH. Struvite precipitation caused a nutrient limitation which prevented biomass concentration increase, thus causing the feast to famine length ratio to vary in the selection reactor, with subsequent impact on the selective pressure for PHA-storing organisms. A highly dynamic response of the selected population to transient conditions of feast to famine ratio, in the range of 0.21–1.1, was observed. Kinetic (limiting concentration of carbon source) and physiological (loss of internal growth limitation due to the shorter length of famine phase) effects, resulting from variation of the influent substrate concentration, were subsequently demonstrated in batch studies. The culture selected at an influent substrate concentration of 45
Cmmol VFA/L showed the best PHA-storing capacity since neither substrate concentration nor feast to famine ratio were limiting factors. This culture, highly enriched in PHA-storing organisms (88%), reached a maximum PHA content of 74.6%.
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•Photo-induced structured waves were analyzed.•Nanostructured topological insulator Bi2Te3 was synthetized.•Two-wave mixing experiments revealed third-order optical effects.
...Third-order nonlinear optical effects were proposed for simultaneous speed modulation of optical and mechanical waves in bismuth telluride nanostructures assisted by an optical two-wave mixing. The optical nonlinearities were investigated under excitation with nanosecond laser pulses at a wavelength of 532 nm. The Bi2Te3 nanostructures were prepared by a simple chemical process. Standard characterization by electrochemical impedance spectroscopy, ellipsometry, UV–Vis absorption and Fourier transform infrared spectrometry was undertaken. The phase purity and vibrational mode of the Bi2Te3 were determined by X-ray diffraction studies and Raman spectroscopy, respectively. The nanocrystal structure and morphology of the Bi2Te3 sample were identified by High-Resolution Transmission Electron Microscopy. The structural characterization and chemical composition of the nanostructures were carried out by Scanning Electron Microscopy combined with Energy Dispersive X-ray spectroscopy. The nanostructured nature of this topological insulator seems to be responsible of its unique polarization-selectable nonlinear optical response. Potential applications for developing structured light systems can be contemplated.
Thin layers of indium tin oxide are widely used as transparent coatings and electrodes in solar energy cells, flat-panel displays, antireflection coatings, radiation protection and lithium-ion ...battery materials, because they have the characteristics of low resistivity, strong absorption at ultraviolet wavelengths, high transmission in the visible, high reflectivity in the far-infrared and strong attenuation in the microwave region. However, there is often a trade-off between electrical conductivity and transparency at visible wavelengths for indium tin oxide and other transparent conducting oxides. Here, we report the growth of layers of indium tin oxide nanowires that show optimum electronic and photonic properties and demonstrate their use as fully transparent top contacts in the visible to near-infrared region for light-emitting devices.
Abstract
Objective
The purpose of this article was to summarize the available evidence from systematic reviews on telerehabilitation in physical therapy.
Methods
We searched Medline/PubMed, EMBASE, ...and Cochrane Library databases. In addition, the records in PROSPERO and Epistemonikos and PEDro were consulted. Systematic reviews of different conditions, populations, and contexts—where the intervention to be evaluated is telerehabilitation by physical therapy—were included. The outcomes were clinical effectiveness depending on specific condition, functionality, quality of life, satisfaction, adherence, and safety. Data extraction and risk of bias assessment were carried out by a reviewer with non-independent verification by a second reviewer. The findings are reported qualitatively in the tables and figures.
Results
Fifty-three systematic reviews were included, of which 17 were assessed as having low risk of bias. Fifteen reviews were on cardiorespiratory rehabilitation, 14 on musculoskeletal conditions, and 13 on neurorehabilitation. The other 11 reviews addressed other types of conditions and rehabilitation. Thirteen reviews evaluated with low risk of bias showed results in favor of telerehabilitation versus in-person rehabilitation or no rehabilitation, while 17 reported no differences between the groups. Thirty-five reviews with unclear or high risk of bias showed mixed results.
Conclusions
Despite the contradictory results, telerehabilitation in physical therapy could be comparable with in-person rehabilitation or better than no rehabilitation for conditions such as osteoarthritis, low-back pain, hip and knee replacement, and multiple sclerosis and also in the context of cardiac and pulmonary rehabilitation. It is imperative to conduct better quality clinical trials and systematic reviews.
Impact
Providing the best available evidence on the effectiveness of telerehabilitation to professionals, mainly physical therapists, will impact the decision-making process and therefore yield better clinical outcomes for patients, both in these times of the COVID-19 pandemic and in the future. The identification of research gaps will also contribute to the generation of relevant and novel research questions.
Neurodevelopmental and late-onset neurodegenerative disorders present as separate entities that are clinically and neuropathologically quite distinct. However, recent evidence has highlighted ...surprising commonalities and converging features at the clinical, genomic, and molecular level between these two disease spectra. This is particularly striking in the context of autism spectrum disorder (ASD) and Parkinson's disease (PD). Genetic causes and risk factors play a central role in disease pathophysiology and enable the identification of overlapping mechanisms and pathways. Here, we focus on clinico-genetic studies of causal variants and overlapping clinical and cellular features of ASD and PD. Several genes and genomic regions were selected for our review, including
(alpha-synuclein),
(parkin RBR E3 ubiquitin protein ligase), chromosome 22q11 deletion/DiGeorge region, and
(fragile X mental retardation 1) repeat expansion, which influence the development of both ASD and PD, with converging features related to synaptic function and neurogenesis. Both PD and ASD display alterations and impairments at the synaptic level, representing early and key disease phenotypes, which support the hypothesis of converging mechanisms between the two types of diseases. Therefore, understanding the underlying molecular mechanisms might inform on common targets and therapeutic approaches. We propose to re-conceptualize how we understand these disorders and provide a new angle into disease targets and mechanisms linking neurodevelopmental disorders and neurodegeneration.
Ecuador is one of the most affected countries, with the coronavirus disease 2019 (COVID-19) infection, in Latin America derived from an ongoing economic crisis. One of the most important methods for ...COVID-19 detection is the use of techniques such as real time RT-PCR based on a previous extraction/purification of RNA procedure from nasopharyngeal cells using functionalized magnetic nanoparticles (MNP). This technique allows the processing of ~ 10,000 tests per day in private companies and around hundreds per day at local Universities guaranteeing to reach a wide range of the population. However, the main drawback of this method is the need for specialized MNP with a strong negative charge for the viral RNA extraction to detect the existence of the SARS-CoV-2 virus. Here we present a simplified low cost method to produce 10 g of nanoparticles in 100 mL of solution that was scaled to one litter by parallelizing the process 10 times in just two days and allowing for the possibility of making ~ 50,000 COVID-19 tests. This communication helps in reducing the cost of acquiring MNP for diverse biomolecular applications supporting developing country budgets constraints and chemical availability specially during the COVID-19 International Health Emergency.
Photoconductive and third-order nonlinear optical properties exhibited by Cu2ZnSnS4 nanostructures are presented. The samples were synthetized in thin film form by a spray pyrolysis processing route. ...Distinctions in the photoconductive behavior throughout the samples were clearly noted by modulating their optoelectronic response dependent on electrical frequency. Vectorial two-wave mixing experiments were carried out at a 532 nm wavelength provided by a Nd:YAG laser system to study the optical nonlinearities in the samples. An induced transparency effect was observed during nanosecond single-beam experiments in the nanostructures reported. Quantum and thermal processes were considered to be the main physical mechanism responsible for the photo-electrical phenomena and nonlinear refraction in the nanostructures. Potential applications for developing nanophotonic and nanoelectronic instrumentation systems can be contemplated.
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