Testing Logselfsimilarity of Soil Particle Size Distribution: Simulation with Minimum Inputs

Particle size distribution (PSD) greatly influences other soil physical properties. A detailed textural analysis is time-consuming and expensive. Soil texture is commonly reported in terms of mass percentages of a small number of size fractions (typically, clay, silt and sand). A method to simulate the PSD from such a poor description or even from the poorest description, consisting in the mass percentages of only two soil size fractions, would be extremly useful for prediction purposes. The goal of this paper is to simulate soil PSDs from the minimum number of inputs, i.e., two and three textural fraction contents, by using a logselfsimilar model and an iterated function system constructed with these data. High quality data on 171 soils are used. Additionally, the characterization of soil texture by entropy-based parameters provided by the model is tested. Results indicate that the logselfsimilar model may be a useful tool to simulate PSD for the construction of pedotransfer functions related to other soil properties when textural information is limited to moderate textural data

Weak Segregation Theory and Non-Conventional Morphologies in the Ternary ABC Triblock Copolymers

The Leibler weak segregation theory in molten diblock copolymers is generalized with due regard for the 2nd shell harmonics contributions defined in the paper and the phase diagrams are built for the linear and miktoarm ternary ABC triblock copolymers. The symmetric linear copolymers with the middle block non-selective with respect to the side ones are shown to undergo the continuous ODT not only into the lamellar phase but also into various non-conventional cubic phases (depending on the middle block composition it could be the simple cubic, face-centered cubic or non-centrosymmetric phase revealing the symmetry of space group No.214 first predicted to appear in molten block copolymers). For asymmetric linear ABC copolymers a region of compositions is found where the weakly segregated gyroid (double gyroid) phase exists between the planar hexagonal and lamellar or one of the non-conventional cubic phases up to the very critical point. In contrast, the miktoarm ABC block copolymers with one of its arm non-selective with respect to the two others are shown to reveal a pronounced tendency towards strong segregation, which is preceded by increase of stability of the conventional BCC phase and a peculiar weakly segregated BCC phase (BCC3), where the dominant harmonics belong to the 3rd co-ordination sphere of the reciprocal lattice. The validity region of the developed theory is discussed and outlined in the composition triangles both for linear and miktoarm copolymers.Comment: 61 pages, 12 figure

SYMBA: An end-to-end VLBI synthetic data generation pipeline: Simulating Event Horizon Telescope observations of M 87

Context. Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are the most important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a direct comparison with observational data. Aims. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. Methods. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a millimetre VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects, compared to the addition of thermal noise only. Using synthetic data based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M 87, we performed case studies to assess the image quality that can be obtained with the current and future EHT array for different weather conditions. Results. Our synthetic observations show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of our GRMHD source models can be recovered robustly with the EHT2017 array after performing calibration steps, which include fringe fitting, a priori amplitude and network calibration, and self-calibration. With the planned addition of new stations to the EHT array in the coming years, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Interstitial docetaxel (Taxotere), carmustine and combined interstitial therapy: a novel treatment for experimental malignant glioma

Docetaxel (Taxotere) is a hemisynthetic, anti-cancer compound with good preclinical and clinical activity in a variety of systemic neoplasms. We tested its activity against malignant gliomas using local delivery methods. Antitumor activity was assessed in vitro against human (U87 and U80 glioma) and rat brain-tumor (9L gliosarcoma and F98 glioma) cell lines. For in vivo evaluation, we incorporated docetaxel into a biodegradable polymer matrix, determined associated toxicity in the rat brain, and measured efficacy at extending survival in a rat model of malignant glioma. Also, we examined the combined local delivery of docetaxel with carmustine (BCNU) against the experimental intracranial glioma. Rats bearing intracranial 9L gliosarcomas were treated 5 days after tumor implantation with various polymers (placebo, 5% docetaxel, 3.8% BCNU, or 5% docetaxel and 3.8% BCNU combination). Animals receiving docetaxel polymers (n=15, median survival 39.1 days) had significantly improved survival over control animals (n=12, median survival 22.5 days, P=0.01). Similarly, animals receiving BCNU polymers (n=15, median survival 39.3 days, 13.3% long-term survivors) demonstrated an increase in survival compared to the controls (P=0.04). Animals receiving the combination polymers demonstrated a modest increase in survival compared to either chemotherapeutic agent alone (n=14, median survival 54.9 days, 28.6% long-term survivors) with markedly improved survival over controls (P=0.003). We conclude that locally delivered docetaxel shows promise as a novel anti-glioma therapy and that the combination of drug regimens via biodegradable polymers may be a great therapeutic benefit to patients with malignant glioma

Local immunotherapy with interleukin-2 delivered from biodegradable polymer microspheres combined with interstitial chemotherapy: a novel treatment for experimental malignant glioma

OBJECTIVE: Local delivery of carmustine (BCNU) from biodegradable polymers prolongs survival against experimental brain tumors. Moreover, paracrine administration of interleukin-2 (IL-2) has been shown to elicit a potent antitumor immune response and to improve survival in animal brain tumor models. We report the use of a novel polymeric microsphere delivery vehicle to release IL-2. We demonstrate both in vitro release of cytokine from the microspheres and histological evidence of the inflammatory response elicited by IL-2 released from the microspheres in the rat brain. These microspheres are and biodegradable polymer wafers are used to deliver BCNU, directly used to deliver IL-2, glioma in the rat. The two agents administered at the site of an intracranially implanted glioma in the rat. The two agents administered locally show a synergistic effect. METHODS: Fischer'344 rats challenged intracranially with 9L gliosarcoma received an intracranial implant of either empty microspheres or microspheres containing IL-2 (IL-2 MS). Five days later, animals in each group were randomized to receive polymer implants loaded with 0, 3.8, or 10% BCNU at the tumor site. RESULTS: Animals that received the combination of IL-2 MS and 3.8% BCNLJ polymer (median survival, 28.5 d) or IL-2 MS and 10% BCNU polymer (median survival, 45.5 d) Showed significantly improved survival compared with animals that received monotherapy with IL-2 microspheres (median survival, 24 d), 3.8% BCNU polymer (median survival, 24 d), or 10% BCNU polymer (median survival, 32.5 d). Control animals had a median survival of 18 days. The combination of either 3.8 or 10% BCNU polymer with IL-2 MS resulted in 7 and 25% long-term survivors, respectively. CONCLUSION: By showing synergy of IL-2 and BCNLJ in an animal glioma model and using a reproducible synthetic delivery system for each agent (i.e., one that did not rely on genetically engineered cells or viruses), we hope that the combination of local immunotherapy and chemotherapy can take an important step closer to clinical application in patients with malignant brain tumor