Primordial black hole mass functions as a probe of cosmic origin

We discuss a novel window to probe the origin of our universe via the mass functions of primordial black holes (PBHs). The mass functions of PBHs are simply estimated using the conventional Press-Schechter formalism for different paradigms of cosmic origin, including inflationary $\Lambda$CDM and bounce cosmology. The standard inflationary $\Lambda$CDM model cannot generate an appreciable number of massive PBHs; however, non-trivial inflation models with blue-tilted power spectra at small scales and matter bounce cosmology provide formation mechanisms for heavy PBHs, which in turn, may seed the observed supermassive black holes (SMBHs). Fitting the observed mass functions of SMBHs in the local universe, we derive for the first time constraints on the PBH current density fraction $f_{\mathrm{PBH}}$ and the characteristic mass $M_{\star}$ for different paradigms of cosmic origin, with the prior assumption that all local SMBHs stem from PBHs. We demonstrate that this newly proposed procedure, relying on astronomical measurements that utilize deep-field scans of SMBHs at high redshift, can in principle be used to constrain models of cosmic origin.Comment: 6 pages, 2 figure

Enhanced Stem Cell Osteogenic Differentiation by Bioactive Glass Functionalized Graphene Oxide Substrates

An unmet need in engineered bone regeneration is to develop scaffolds capable of manipulating stem cells osteogenesis. Graphene oxide (GO) has been widely used as a biomaterial for various biomedical applications. However, it remains challenging to functionalize GO as ideal platform for specifically directing stem cell osteogenesis. Herein, we report facile functionalization of GO with dopamine and subsequent bioactive glass (BG) to enhance stem cell adhesion, spreading, and osteogenic differentiation. On the basis of graphene, we obtained dopamine functionalized graphene oxide/bioactive glass (DGO/BG) hybrid scaffolds containing different content of DGO by loading BG nanoparticles on graphene oxide surface using sol-gel method. To enhance the dispersion stability and facilitate subsequent nucleation of BG in GO, firstly, dopamine (DA) was used to modify GO. Then, the modified GO was functionalized with bioactive glass (BG) using sol-gel method. The adhesion, spreading, and osteoinductive effects of DGO/BG scaffold on rat bone marrow mesenchymal stem cells (rBMSCs) were evaluated. DGO/BG hybrid scaffolds with different content of DGO could influence rBMSCs’ behavior. The highest expression level of osteogenic markers suggests that the DGO/BG hybrid scaffolds have great potential or elicit desired bone reparative outcome

Towards Visual Foundational Models of Physical Scenes

We describe a first step towards learning general-purpose visual representations of physical scenes using only image prediction as a training criterion. To do so, we first define "physical scene" and show that, even though different agents may maintain different representations of the same scene, the underlying physical scene that can be inferred is unique. Then, we show that NeRFs cannot represent the physical scene, as they lack extrapolation mechanisms. Those, however, could be provided by Diffusion Models, at least in theory. To test this hypothesis empirically, NeRFs can be combined with Diffusion Models, a process we refer to as NeRF Diffusion, used as unsupervised representations of the physical scene. Our analysis is limited to visual data, without external grounding mechanisms that can be provided by independent sensory modalities.Comment: TLDR: Physical scenes are equivalence classes of sufficient statistics, and can be inferred uniquely by any agent measuring the same finite data; We formalize and implement an approach to representation learning that overturns "naive realism" in favor of an analytical approach of Russell and Koenderink. NeRFs cannot capture the physical scenes, but combined with Diffusion Models they ca

Attenuating Immune Response of Macrophage by Enhancing Hydrophilicity of Ti Surface

Immune responses can determine the in vivo fate of implanted materials. The strategy for developing implants has shifted towards using materials with immunomodulatory activity. However, the immunoregulatory effect of hydrophilicity of titanium surface on the macrophage behavior and its underlying mechanism remain poorly understood. Here, the Ti surface hydrophilicity-dependent behavior of murine RAW264.7 macrophages was investigated in vitro. Two laboratory models with significantly different surface hydrophilicity and similar roughness were established with Ti-polished and Ti-H2O2 surfaces. The results of cell morphology observation showed that the Ti-H2O2 surface yielded enhanced cell adhesion and less multinucleated cell formation. CCK-8 assay indicated that the growth rate of macrophage on Ti-H2O2 surface is higher than that of Ti-polished. ELISA assay result revealed lower level of proinflammatory factor TNF-α and higher level of anti-inflammatory factor IL-10 on the Ti-H2O2 surface compared to Ti-polished. Subsequently, immunofluorescence and western blotting analysis showed that activation of the NF-κB-TNF-α pathway might be involved in the modulation of the immune response by surface hydrophilicity. Together, these results suggested that relative high hydrophilic Ti surface might attenuate the immune response of macrophage by activating NF-κB signaling. These findings could provide new insights into designing implant devices for orthopedic applications

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Do long-term high nitrogen inputs change the composition of soil dissolved organic matter in a primary tropical forest?

Dissolved organic matter (DOM) plays a key role in forest carbon biogeochemistry by linking soil organic carbon (SOC) sequestration and water fluxes, which is further shaped by elevated atmospheric nitrogen (N) deposition. Although enhanced SOC sequestration was evidenced in tropical forests due to rising N deposition, it remains unclear how long-term N inputs affect soil DOM composition, which regulates SOC sequestration capability due to its mobility and biological instability. Here, the quantity, optical properties, and molecular-level characteristics of soil DOM based on a simulative N deposition experiment with four N addition levels (0, 5, 10, and 15 g m ^−2 yr ^−1 ) were studied in a primary tropical forest in south China. Results showed that 18 year N additions significantly altered soil DOM composition, with an increasing trend in soil dissolved organic carbon content. Medium- (10 g m ^−2 yr ^−1 ) and high-N addition (15 g m ^−2 yr ^−1 ) markedly elevated DOM average molecular weight by 12% and aromaticity, with specific ultraviolet absorbance at 254 nm increasing by 17%, modified aromatic index by 35%, and condensed aromatics by 67%. Medium- and high-N addition also increased recalcitrant DOM components but decreased other DOM components, with increasing percentages of lignin-like, tannin-like, and carboxylic-rich alicyclic molecule-like compounds, and decreasing percentage of more bioavailable contributions with H/C ratio >1.5. Importantly, significant correlations of the SOC content of the heavy fraction with optical properties and with recalcitrant DOM components were observed. These findings suggest that long-term N additions may alter soil DOM composition in a way to benefit soil OC storage in the primary tropical forests. It merits focusing on the mechanisms to association of soil DOM dynamics with SOC sequestration

Synthesis of Uniform Bi₂WO₆‑Reduced Graphene Oxide Nanocomposites with Significantly Enhanced Photocatalytic Reduction Activity

In this work, the uniform B₂WO₆-reduced graphene oxide (BWO–RGO) nanocomposites are prepared via electrostatic self-assembly of positively charged BWO with negatively charged GO sheets and then the composited GO is reduced via the hydrothermal treatment. The close interfacial contact and strong electronic interaction between BWO and RGO are achieved by this facile and efficient self-assembly route. Photocatalytic degradation of pollutant bisphenol A, selective oxidation of benzyl alcohol, removal of heavy metal ion Cr­(VI), and selective reduction of 4-nitrophenol are selected as the probe reactions to investigate the photocatalytic activities of as-obtained BWO–RGO nanocomposites. The experimental results demonstrate the photocatalytic redox activities of BWO–RGO composites are predominantly dependent on the energy levels of photoinduced electrons or holes. In particular, the upshift of the valence band and conduction band edge of catalysts induced by the electronic interaction between BWO and RGO has an inconsistent influence on the photocatalytic reduction and oxidation reactions, respectively. As a result, the photocatalytic activity of reduction reactions is significantly enhanced, owing to the synergetic effect of the upshift of conduction band edge and the improved separation of photogenerated electrons/holes, while the oxidation ability of BWO–RGO nanocomposite is improved to a slight extent compared with bare BWO. The energy levels of photogenerated carriers should be the origins accounting for the different enhancement of photocatalytic activities for the different reactions. According to the discussion, one important conclusion can be drawn, that is, the results should be analyzed on the basis of specific reactions when discussing the effect of graphene or RGO on the photocatalytic properties of semiconductor particles

Biology and chemistry of an Umbravirus like 2989 bp single stranded RNA as a possible causal agent for Opuntia stunting disease (engrosamiento de cladodios)-A Review.

Perhaps the most economically important disease of Opuntia ficus indica fruit cacti in Mexico is the “engrosamiento de cladodios” or macho disease. The symptoms of this disease, which has been suggested to be caused by a phytoplasma, are severe stunting of cladodes, flowers and fruits. In the mid-1980s this disease appeared in commercial cactus fruit orchards of D’Arrigo Bros near Gonzalez, California. It was performed more than 30 PCR-based tests for viruses as well as various extraction methods and polymerase chain reaction (PCR) tests for phytoplasmas but were unable to find any of the known viruses or mycoplasmas in the strongly symptomatic cactus with this disease. As almost all plant viruses go through a replication phase involving double stranded RNA (dsRNA), a dsRNA extraction was performed and a dsRNA species of about 600 bp identified. Then, reverse-transcribed the dsRNA, amplified the resultant cDNA by PCR, and cloned and sequenced the 600 bp fragment that were identified in symptomatic tissue. When this sequence was compared to translated DNA in the National Center for Biotechnology Information (NCBI) nucleotide data base (BLAST analysis) it was most similar to the Tobacco bushy top virus (E score of 2e-39), which is a single stranded RNA virus with no DNA intermediate. Primers made from this 630 bp fragment were used to extend this sequence to 2989 sequence. This sequence appears to be a full-length sequence with three open reading frames (ORF) and is shorter than the closest class of viruses, the Umbraviruses that can be spread by mechanical transmission and by aphids. It was not possible to transmit the virus or symptoms mechanically. Over a six-year period using traditional PCR, this virus was found in hundreds of symptomatic cacti but not in non-symptomatic pads. RT-PCR has found low levels of this virus on nonsymptomatic cladodes (3.7 fg) on a symptomatic plant and much higher concentrations (1x102 to 1x105 fg) on symptomatic cladodes from the same plant. Black bean aphids (Aphis Felker et al., 2019. JPACD (2019) 21:1-31 2 fabae), that are the vector for a closely related Umbravirus known as groundnut rosetta virus, have been routinely found on the unopened flowers of cactus. This Umbravirus was found in aphids feeding on symptomatic cladodes. As Umbraviruses cannot infect plants without a companion Luteovirus, that provides the protein coat for the Umbravirus, degenerate Luteovirus primers were used and a probable incomplete Luteovirus-like 4797 bp sequence was found on aphids feeding on symptomatic cactus. This Luteovirus was not found in Opuntia cladodes using PCR. A micro RNA assembly of six pooled symptomatic Opuntias did not find a contig that spanned the 4797 putative Luteovirus sequence, but some fragments as large as 44 bp were exact matches to the Luteovirus. As Umbraviruses occur throughout the plant but Luteoviruses only occur in the phloem, lower Luteovirus concentrations would be expected. Two successive one hour 60°C heat treatments eliminated these symptoms on new growth that was also PCR negative. A 5839 bp Potexvirus was found in some of these cladodes but its presence was not correlated with any symptoms. Similar symptomatic cacti in Italy, South Africa and Mexico should be examined with these primers and dsRNA to see if similar correlations between presence/absence of this fragment and symptomatic plants can be obtained. It is suggested that this disease be known as OSD (Opuntia Stunting Disease)