ABSTRACT
The first known asteroid with the orbit inside that of Venus is 2020 AV2. This may be the largest member of a new population of small bodies with the aphelion smaller than 0.718 au, called ...Vatiras. The surface of 2020 AV2 is being constantly modified by the high temperature, by the strong solar wind irradiation that characterizes the innermost region of the Solar system, and by high-energy micrometeorite impacts. The study of its physical properties represents an extreme test-case for the science of near-Earth asteroids. Here, we report spectroscopic observations of 2020 AV2 in the 0.5–1.5-μm wavelength interval. These were performed with the Nordic Optical Telescope and the William Herschel Telescope. Based on the obtained spectra, we classify 2020 AV2 as a Sa-type asteroid. We estimate the diameter of this Vatira to be $1.50_{-0.65}^{+1.10}$ km by considering the average albedo of A-type and S-complex asteroids ($p_V=0.23_{-0.08}^{+0.11}$), and the absolute magnitude (H = 16.40 ± 0.78 mag). The wide spectral band around 1 μm shows the signature of an olivine-rich composition. The estimated band centre BIC = 1.08 ± 0.02 μm corresponds to a ferroan olivine mineralogy similar to that of brachinite meteorites.
Pseudomonas aeruginosa : all roads lead to resistance Breidenstein, Elena B.M; de la Fuente-Núñez, César; Hancock, Robert E.W
Trends in microbiology (Regular ed.),
08/2011, Letnik:
19, Številka:
8
Journal Article
Recenzirano
Pseudomonas aeruginosa is often resistant to multiple antibiotics and consequently has joined the ranks of ‘superbugs’ due to its enormous capacity to engender resistance. It demonstrates decreased ...susceptibility to most antibiotics due to low outer membrane permeability coupled to adaptive mechanisms and can readily achieve clinical resistance. Newer research, using mutant library screens, microarray technologies and mutation frequency analysis, has identified very large collections of genes (the resistome) that when mutated lead to resistance as well as new forms of adaptive resistance that can be triggered by antibiotics themselves, in in vivo growth conditions or complex adaptations such as biofilm growth or swarming motility.
► Atmospheric corrosion rate stabilises after the first 4–6
years of exposure. ► Great compaction of the rust layers in rural and urban atmospheres. ► Corrosion (in rural and urban) deviates from ...common behaviour of bilogarithmic law. ► Typical structures of lepidocrocite, goethite and akaganeite are identified. ► Formation of hematite (industrial atmosphere) and ferrihydrite (marine atmosphere).
A great deal of information is available on the atmospheric corrosion of mild steel in the short, mid and even long term, but studies of the structure and morphology of corrosion layers are less abundant and generally deal with those formed in just a few years. The present study assesses the structure and morphology of corrosion product layers formed on mild steel after 13
years of exposure in five Spanish atmospheres of different types: rural, urban, industrial and marine (mild and severe). The corrosion layers have been characterised by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Long-term corrosion is seen to be more severe in the industrial and marine atmospheres, and less so in the rural and urban atmospheres. In all cases the corrosion rate is seen to decrease with exposure time, stabilising after the first 4–6
years of exposure. The most relevant aspects to be noted are (a) the great compaction of the rust layers formed in the rural and urban atmospheres, (b) the formation of hematite and ferrihydrite phases (not commonly found) in the industrial and marine atmospheres, respectively and (c) identification of the typical morphological structures of lepidocrocite (sandy crystals and flowery plates), goethite (cotton balls structures) and akaganeite (cotton balls structures and cigar-shaped crystals).
Object
Diffuse tumor invasion in multifocal/multicentric GBM (mGBM) often foreshadows poor survival outcome. The correlation between extent of resection in gliomas and patient outcome is well ...described. The objective of this study was to assess the effect of gross total resection compared to biopsy for mGBM on patient overall survival and progression free survival.
Methods
Thirty-four patients with mGBM received either biopsy or resection of their largest enhancing lesion from 2011 to 2019. Relevant demographic, peri-operative, and radiographic data were collected. Tumor burden and extent of resection was assessed through measurement of pre-operative and post-operative contrast-enhancing volume. An adjusted Kaplan–Meier survival analysis was conducted using inverse probability of treatment weighting (IPTW) to account for the covariates of age, number of lesions, satellite tumor volume, total pre-operative tumor volume, degree of spread, and location.
Results
Thirty-four patients were identified with sixteen (47.1%) and eighteen (52.9%) patients receiving resection and biopsy respectively. Patients receiving resection exhibited greater median overall survival but not progression free survival compared to biopsy on IPTW analysis (p = 0.026, p = 0.411). Greater than or equal to 85% extent of resection was significantly associated with increased median overall survival (p = 0.016).
Conclusion
Overall, our study suggests that resection of the largest contrast-enhancing lesion may provide a survival benefit. Our volumetric analysis suggests that a greater degree of resection results in improved survival. Employing IPTW analysis, we sought to control for selection bias in our retrospective analysis. Thus, aggressive surgical treatment of mGBM may offer improved outcomes. Further clinical trials are needed.
The brain is a site of relative immune privilege. Although CD4 T cells have been reported in the central nervous system, their presence in the healthy brain remains controversial, and their function ...remains largely unknown. We used a combination of imaging, single cell, and surgical approaches to identify a CD69+ CD4 T cell population in both the mouse and human brain, distinct from circulating CD4 T cells. The brain-resident population was derived through in situ differentiation from activated circulatory cells and was shaped by self-antigen and the peripheral microbiome. Single-cell sequencing revealed that in the absence of murine CD4 T cells, resident microglia remained suspended between the fetal and adult states. This maturation defect resulted in excess immature neuronal synapses and behavioral abnormalities. These results illuminate a role for CD4 T cells in brain development and a potential interconnected dynamic between the evolution of the immunological and neurological systems.
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•Residential CD4 T cells are present in the healthy mouse and human brain•Brain residency is a transient program initiated in situ and lasting weeks•CD4 T cell entry around birth drives a transcriptional maturation step in microglia•Absence of CD4 T cells results in defective synaptic pruning and behavior
Identification of brain-resident CD4+ T cells in mice and humans, which are required for microglia maturation and proper synaptic pruning and behavior.
The interaction between immune and stem cells has proven essential for homeostasis and regeneration in a wide range of tissues. However, because the central nervous system was long considered an ...immune‐privileged organ, its immune–stem cell axis was not deeply investigated until recently. Research has shown that oligodendrocyte progenitor cells (OPCs), a highly abundant population of adult brain stem cells, establish bidirectional interactions with the immune system. Here, we provide an overview of the interactions that OPCs have with tissue‐resident and recruited immune cells, paying particular attention to the role they play in myelin regeneration and neuroinflammation. We highlight the described role of OPCs as key active players in neuroinflammation, overriding the previous concept that OPCs are mere recipients of immune signals. Understanding the mechanisms behind this bidirectional interaction holds great potential for the development of novel therapeutic approaches limiting neuroinflammation and promoting myelin repair. A better understanding of the central nervous system's immune–stem cell axis will also be key for tackling two important features shared across neurodegenerative diseases, neuroinflammation and myelin loss.
In this review, we discuss the bidirectional interaction between oligodendrocyte progenitor cells (OPCs) and the immune system in central nervous system health and disease. We focus on describing two main aspects: (a) how immune cells regulate OPC biology and their regenerative capacity, and (b) describe the novel immune regulatory roles of OPCs. Understanding the crosstalk between OPCs and the immune system will open new avenues for tackling neuroinflammatory diseases.
Pristine, hybrid or composite aerogels and xerogels based on carbon allotropes are reviewed. Carbon aerogels applied as sorbents for distinct organic liquids are mainly composed of graphene or ...graphene oxide (GO) hybrids, carbon nanotubes (CNTs) composites, as well as by hybrids of other carbon nanostructures. Aerogels are generally prepared by the aging of gels (hydrogels or alcogels), drying (mostly by vacuum freeze-drying), and pyrolysis/carbonization. Carbon xerogels are synthesized usually by traditional sol-gel based method from resorcinol and formaldehyde (gels formation), aging, drying (at atmospheric pressure) and pyrolysis/carbonization, being drying method the principal difference between aerogels and xerogels fabrication. A certain number of carbon-containing aerogels can be obtained from natural sources: corn bracts, waste newspaper, bleached softwood kraft pulp, bamboo fiber cotton, or sisal fibers, among others. These precursors are inexpensive, renewable and, on some occasions, wastes are used that would otherwise be discarded. Hybrid and composite carbon aerogels also can be obtained using natural sources as raw material. Outstanding properties of aerogels are high specific surface area, super-compressibility, and high adsorption capacity. Specific properties such as improved surface roughness or magnetic property of aerogels can be tailored by the incorporation of certain nanostructures. Xerogels are less popular as effective adsorption materials, but their fabrication is possible at normal pressure, influencing their cost. Both carbon aerogels and xerogels, due to their exceptional sorbent performance, high selectivity, and reusability, are excellent options for a series of adsorbent purposes. In this paper, an in-depth study of carbon aerogels and xerogels is presented, including their synthesis, use as oil sorbents, properties, and sorption capacities. Additionally, this information is displayed in tabular form (Supplementary Material) for easy comparison.
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•Carbon aerogels can be prepared by formation of hydrogels or alcogels, vacuum freeze-drying and pyrolysis/carbonization.•Hybrid and composite aerogels are made of graphene with CNT, carbon fibers or spheres, CNTs-carbon nanofibers, among others.•Carbon aerogels have reached ultrahigh sorption capacities up to 734 g/g.•Tailored surface nanoroughness can be developed by the addition or in situ growth of metal oxides nanomaterials.•Carbon aerogels and xerogels are excellent materials in the separation of oil-water mixtures and emulsions.
•Antiferromagnetics-based coercivity control in hematite/permalloy heterostructures.•Magnetic and structural studies of epitaxial hematite thin films across the Morin transition.•Thickness dependence ...of the Interfacial coupling between hematite and permalloy across Morin transition.
Interfacial effects between antiferromagnetic (AFM) and ferromagnetic (FM) materials have long been a center of magnetism studies. Aside from the exchange bias occurring at the AFM/FM interface, controlling the coercivity is another significant topic in magnetic recordings. The coercivity of FM materials is often determined through varying grain size, alloy composition, density of defects, etc., which is set during material growth and offers limited room for modification after growth. Hematite (α-Fe2O3) is an AFM material that undergoes a temperature-controlled spin-flip transition, the so-called Morin transition. This transition gives an extra degree of freedom making hematite an intriguing component to study the exchange coupling when interfaced with an FM material. In this work, changes in the magnetic properties of soft magnetic permalloy (Ni81Fe19, or Py) thin films grown on hematite were studied across the Morin transition. Surprisingly, these samples showed a remarkable change in coercivity during the Morin transition. We attribute this effect to the magnetic domain mixture of hematite during the Morin transition. Our findings present a novel method of controlling the coercivity of plain ferromagnetic thin films.
Allogeneic hemopoietic stem cell transplantation (HSCT) is the only method currently available to cure transfusion-dependent thalassemia major that has been widely used worldwide. To verify ...transplantation distribution, demography, activity, policies and outcomes inside the European Group for Blood and Marrow Transplantation (EBMT), we performed a retrospective non-interventional study, extracting data from the EBMT hemoglobinopathy prospective registry database. We included 1493 consecutive patients with thalassemia major transplanted between 1 January 2000 and 31 December 2010. In total, 1359 (91%) transplants were performed on patients <18 years old, 1061 were from a human leukocyte Ag-identical sibling donor. After a median observation time of 2 years, the 2-year overall survival (OS) and event-free survival (EFS; that is, thalassemia-free survival) were 88 ± 1% and 81 ± 1%, respectively. Transplantation from a human leukocyte Ag-identical sibling offered the best results, with OS and EFS of 91 ± 1% and 83 ± 1%, respectively. No significant differences in survival were reported between countries. The threshold age for optimal transplant outcomes was around 14 years, with an OS of 90-96% and an EFS of 83-93% when transplants were performed before this age. Allogeneic HSCT for thalassemia is a curative approach that is employed internationally and produces excellent results.
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