Purpose
Several interactions exist between the GH/IGF axis and the immune system, including effects on innate immunity and humoral and cellular response. Acquired GH deficiency (GHD) has been ...recently proposed as a risk factor for severity of COVID-19 infections. However, acquired GHD is often associated to other factors, including pituitary tumors, surgery, radiotherapy, and additional pituitary hormones deficits and their replacements, which, together, may hinder an accurate analysis of the relationship between GHD and COVID-19. Therefore, we decided to assess the seroprevalence of SARS-CoV-2 antibodies and the frequency of symptomatic cases of COVID-19 in adults subjects with untreated isolated GHD (IGHD) due to a homozygous
null
mutation in the GHRH receptor gene.
Methods
A cross-sectional study was carried out in 27 adult IGHD subjects and 27 age- and gender-matched local controls. Interview, physical examination, bio-impedance, hematological and SARS-CoV-2 IgM and IgG antibodies were analyzed.
Results
There was no difference in the prevalence of positivity of anti-SARS-CoV-2 IgM and IgG antibodies between the two groups. Conversely, no IGHD individual had a previous clinical diagnosis of COVID-19 infection, while 6 control subjects did (
p
= 0.023).
Conclusion
The production of anti-SARS-CoV-2 antibodies was similar between IGHD subjects due to a GHRH receptor gene mutation and controls, but the evolution to symptomatic stages of the infection and the frequency of confirmed cases was lower in IGHD subjects than in GH sufficient individuals.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Na super ionic CONductor (NASICON), Na1+x Zr2Si x P3–x O12, is an excellent solid-state electrolyte on account of its high sodium-ion conductivity, which can be further enhanced through chemical ...doping. However, the underlying sodium diffusion mechanism and how it is affected by chemical doping are not fully understood. This, in part, stems from the ambiguity between reported average structure models, where there is variation in the number and location of the sodium crystallographic sites. In this work, we present a neutron scattering study on monoclinic NASICON and Mg2+-doped NASICON, with a focus on the characterization of the sodium sites. Our difference Fourier maps show that the sodium sites have limited long-range order at temperatures as low as 3 K. In addition, our characterization of Mg2+-doped NASICON suggests that although Mg2+ preferentially dopes the secondary Na3PO4 phase rather than the bulk NASICON phase, its NASICON sodium sites are comparatively more diffuse. Furthermore, quasi-elastic neutron scattering data show broader spectra for the Mg-doped NASICON compared to NASICON at 300 K, supporting a more dynamic environment. We propose that the more diffuse character of the sodium sites arising from the introduction of Mg2+ contributes to the improvement of ionic conductivity in Mg-doped NASICON near room temperature.
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IJS, KILJ, NUK, PNG, UL, UM
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.
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IJS, KILJ, NUK, PNG, UL, UM
14.
Accurate Image-guided (Re)Placement of NIRS Probes Wu, Shin-Ting; Rubianes Silva, José Angel Iván; Novi, Sergio Luiz ...
Computer methods and programs in biomedicine,
March 2021, 2021-Mar, 2021-03-00, 20210301, Volume:
200
Journal Article
Peer reviewed
Open access
•Development of a neuronavigation system using electromagnetic digitizer.•Design of a holder of the digitizer’s accessories to improve the accuracy of its alignment with a real head.•Presentation of ...a GPU-based rendering of visual objects at interactive rates.•Solution for unambiguous depth perception to improve the accuracy of the placement of probes.•Proposal of a procedure to improve the reproducibility of digitized points.•Assessment of intra-subject fNIRS reproducibility using the proposed neuronavigation system.
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.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The flame-retardant properties of polydimethylsiloxane (PDMS)/oxidised multi-walled carbon nanotubes (MWCNT–COOH) nanocomposite films were dispersed using a nonionic acrylate copolymer surfactant. ...The nanocomposite films were prepared by spin coating and characterised using SEM, quasi-elastic cold-neutron scattering, TGA–FTIR, cone calorimetry, and LOI. The PDMS/surfactant/MWCNT–COOH (PSM) nanocomposite displayed superior flame-retardant performance compared to materials containing only surfactant or MWCNT–COOH. The peak heat release rate, the peak smoke production rate, total smoke release rate, carbon monoxide, and carbon dioxide production from PSM were 42, 47, 18, 28, and 47% less than the PDMS control. The LOI results for PSM exhibited a value of 32% with respect to 25% for the PDMS. PSM suppresses the smoke emission and inhibits penetration of the air reacting with the gas volatiles of the material. These new nanocomposites provide a valuable improvement in flame-retardant capabilities by physical barrier effect compared to other PDMS polymer materials.
Graphic abstract
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The new coronavirus has been affecting health worldwide and essential service workers are continually exposed to this infectious agent, increasing the chance of infection and the development of the ...disease. Thus, this study aimed to estimate the frequency of infection and seroprevalence for SARS-CoV-2 in military firefighters in a city in Northeastern Brazil in January 2021. An observational cross-sectional study was carried out with 123 firefighters who answered a brief questionnaire to collect socio-epidemiological data and underwent RT-PCR and immunofluorescence test (IgM and IgG). The results found reveal a positive seroprevalence, with a high rate of infection in this class of workers, since they are essential service professionals who are exposed to risk due to their working hours, in addition to sharing some spaces and work materials. Besides, there were significant associations between positivity for IgG and IgM, as well as for positive RT-PCR prior to the study and the presence of IgG, with odd ratios of 3.04 and 4.9, respectively. These findings reinforce the need for immunization in this category, whose line of service hinders the adoption of distancing measures, since in many situations physical contact is inevitable.
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.
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IJS, KILJ, NUK, PNG, UL, UM
The Earth's polar regions are experiencing a greater frequency of freeze-thaw events throughout the polar summer, contributing to atmospheric methane and destabilising clay-rich sediments. Clays in ...soils tightly bind pore water and thus substantially modify freeze-thaw events. While temperatures of phase transitions for confined pore water may be precisely assessed using calorimetric or thermal analyses to −30 or −40 °C, neutron scattering directly probes how pores in clay minerals control ice formation and melting to lower temperatures. We apply elastic neutron scattering to accurately quantify the unfrozen water content of clay gels and unambiguously identify different pore-water environments by their freezing temperatures. Using this approach, we conclude that cryosuction controls water mobility in frozen soils in the absence of soluble salts to much lower temperatures than observed by other techniques. Dyanmics determined from neutron scattering indicates that water in clay gel pores thaws at much lower temperatures than currently considered, and thus pose potential risks for contaminant migration at sub freezing temperatures. The general poor strength of wet clays can significantly impact infrastructure in cold regions undergoing an increased frequency of freeze-thaw events.
Different pore water environments in clay gels can be identified and quantified by inelastic neutron scattering. Display omitted
•Cryosuction removes interlayer water from clay gels hydrated to near saturation.•Cryosuction requires capillary connectivity to operate in clay gels.•Considerable interlayer water remains unfrozen in clay gels to below −80C.•Freezing characteristic curves can be used to identify pore environments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The shielding for the neutron high-resolution backscattering spectrometer (EMU) located at the OPAL reactor (ANSTO) was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design ...has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
ABSTRACT During the production of petroleum and gas, the equipments employed for this activity are subjected to synergetic wear mechanisms, such as corrosion, corrosion-cavitation and ...corrosion-cavitation-erosion. Laboratory experiments has been performed to reproduce some of these mechanisms, however, sometimes the tests is not capable to recreate the complexities caused by hydrodynamic flows, physico-chemical and mechanical non-linearities. The main objective of this work is to evaluate specimens of low carbon steel under laboratory conditions, such as corrosive, cavitative-corrosive (CO2) and corrosive-erosive (CO2 + SiO2) environments. During the tests, the specimens were subjected to a stirring aqueous saline solution (0 and 5.0 m/s) at two levels of temperature, with gas injection (5.0 L/min) and contaminated with by solids particles of SiO2 (2.5% mass). The surface of the specimens subjected to upstream flow (0° in a cylindrical generatrix of the specimen), and downstream flows (180º) were analyzed by profilometry. The measurements of roughness and waviness of all specimens were statistically analyzed at a confidence level of 95% and significant differences observed in some matrices were discussed. The results suggest that the wear mechanisms that act in the upstream generatrix differ from that of specimen downstream.
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