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Up to eight percent of the sand in concrete and mortar used to make a single-story house could be replaced with shredded used disposable diapers without significantly diminishing their strength, according to a study published in Scientific Reports. The authors suggest that disposable diaper waste could be used as a construction material for low-cost housing in low- and middle-income countries.

Disposable diapers are usually manufactured from wood pulp, cotton, viscose rayon, and plastics such as polyester, polyethylene, and polypropylene. The majority are disposed of in landfill or by incineration.

Siswanti Zuraida and colleagues prepared concrete and mortar samples by combining washed, dried, and shredded disposable diaper waste with cement, sand, gravel, and water. These samples were then cured for 28 days. The authors tested six samples containing different proportions of diaper waste to measure how much pressure they could withstand without breaking. They then calculated the maximum proportion of sand that could be replaced with disposable diapers in a range of building materials that would be needed to construct a house with a floorplan area of 36 square metres that complies with Indonesian building standards.

The authors found that disposable diaper waste could replace up to ten percent of the sand needed for concrete used to form columns and beams in a three-story house. This proportion increased to 27 percent of sand needed for concrete columns and beams in a single-story house. Up to 40 percent of the sand needed for mortar in partition walls can be replaced with disposable diapers, compared to nine percent of the sand in mortar for floors and garden paving. Together, up to eight percent of the sand in all of the concrete and mortar building materials required to build a single-story house with a floorplan of 36 square metres can be replaced with disposable diaper waste — equivalent to 1.7 cubic metres of waste.

The authors note that wider implementation of their findings would require the involvement of stakeholders in government and waste treatment in developing processes for the large-scale collection, sanitising, and shredding of diaper waste. Additionally, building regulations would need to be modified to allow the use of diaper waste as a construction material.

A dinosaur specimen from Castellón, Spain represents a new proposed species of spinosaurid, reports a paper published in Scientific Reports. The identification of a potential new species suggests that the Iberian peninsula may have been a diverse area for medium-to-large bodied spinosaurid dinosaurs and sheds light on the origin and evolution of spinosaurids.

Spinosaurids comprise of different groups of dinosaurs that are often large, stand on two feet, and are carnivorous. Well-known examples of spinosaurids include Spinosaurus and Baryonyx. It is thought that spinosaurids may have originated in Europe and then migrated to Africa and Asia, but evidence of their existence in Spain is mostly based on fossilised tooth remains.

Andrés Santos Cubedo and colleagues analysed fossil fragments (a right jaw bone, one tooth and five vertebrae) discovered previously in the Arcillas de Morella Formation in Spain and dated to the late Barremian, Early Cretaceous period (between 127 and 126 million years ago). Based on the remains the authors estimate that the specimen is around 10 to 11 metres long. They compared the specimen to data on other spinosaurids to determine its evolutionary relationship to other species.

Based on a comparative analysis of the specimen with other spinosaurids, the authors identified the specimen as both a new species and a new genus of spinosaurid and named it Protathlitis cinctorrensis. The authors named the genus Protathlitis meaning “champion” in Greek and used cinctorrensis in the species name to reference the town — Cinctorres — in which the specimen was uncovered.

The authors propose that this new species may indicate that spinosaurids appeared during the Early Cretaceous in Laurasia — a large area of land in the northern hemisphere — with two sub-groups of species occupying western Europe. The spinosaurids may have later migrated to Africa and Asia where they diversified. In Europe, baryonychines like Protathlitis were dominant, while in Africa, spinosaurines like Spinosaurus were most abundant.

Human origins in Africa may be best described using a model in which at least two evolutionary branches split (but continued to mix) over hundreds of thousands of years, according to a paper in Nature. This so-called weakly structured stem is proposed to have contributed to the formation of an ancestral African human group that then diverged into contemporary African populations, as well as all populations living outside of Africa.

Although it is widely understood that Homo sapiens originated in Africa, uncertainty surrounds how branches of human evolution diverged and people migrated across the continent. This uncertainty is due to limited fossil and ancient genomic data, and to the fact that the fossil record does not always align with expectations from models built using modern DNA.

Aaron Ragsdale, Brenna Henn, Simon Gravel and colleagues tested a range of competing models of evolution and migration across Africa proposed in the palaeoanthropological and genetics literature, incorporating population genome data from southern, eastern and western Africa. The authors included newly sequenced genomes from 44 modern Nama individuals from southern Africa, an Indigenous population known to carry exceptional levels of genetic diversity compared with other modern groups. The model suggests the earliest population split among early humans that is detectable in contemporary populations occurred 120,000 to 135,000 years ago, after two or more weakly genetically differentiated Homo populations had been mixing for hundreds of thousands of years. After the population split, ancient hominins still migrated between the stem populations, creating a weakly structured stem — this offers a better explanation of genetic variation among individual humans and human groups than do previous models, the authors suggest.

The authors predict that according to this model, 1–4% of genetic differentiation among contemporary human populations can be attributed to variation in the stem populations. This model may have important consequences for the interpretation of the fossil record — owing to migration between the branches, these multiple lineages were probably morphologically similar, which means morphologically divergent hominid fossils (such as Homo naledi) are unlikely to represent branches that contributed to the evolution of Homo sapiens.

New genetic variants that are linked to the development of critical illness in patients with COVID-19 are reported in Nature. The findings, which build on previous analyses, improve our understanding of the factors that underlie severe COVID-19 and highlight targets for drug development.

Previous genome-wide association studies by GenOMICC have shed light on the genetic factors that might influence disease severity in about 10,000 patients who were critically ill with COVID-19. In the latest update, Kenneth Baillie and colleagues analysed genomic data from 24,202 patients who were critically ill with COVID-19 and identified 49 genetic variants underlying critical illness, of which 16 had not been reported previously. To explore potential therapeutic implications, the authors combined these results with gene and protein expression data and identified 114 potential drug targets. For example, targets relating to genes involved in the body’s response to invading viruses and inflammatory processes.

The authors suggest that repurposing existing drugs could potentially target these pathways to help treat patients who are seriously ill with COVID-19. For example, they found an association of critical COVID-19 with the gene that encodes JAK1, a protein involved in inflammatory signalling, and which is a target of the rheumatoid arthritis treatment baricitinib, thus offering a potential avenue for drug repositioning. These results enhance our understanding as well as offering new insights, some of which may have potential therapeutic applications.

The US Food and Drug Administration approved diagnostic substance indocyanine green reduces the toxicity of α-amanitin, a toxin produced by the world’s most poisonous mushroom — the death cap — in human cell lines and mice, according to a Nature Communications paper. The findings suggest that this substance could present a potential antidote treatment for death cap poisoning in humans, which are responsible for over 90% of mushroom-related deaths worldwide.

Mushroom poisoning is the main cause of mortality in food poisoning incidents worldwide. In China alone, almost 40,000 illnesses and 788 deaths were reported between 2010–2020. α-amanitin is the main toxin produced by the death cap mushroom and causes high rates of irreparable liver or kidney damage and mortality following consumption. Despite its lethal effects, the exact molecular mechanisms of α-amanitin’s toxicity remain unclear, and no specific antidote is currently available.

Qiaoping Wang and colleagues used genome-wide CRISPR screening to identify molecular targets for α-amanitin and found that the protein STT3B, a key component of the N-glycan biosynthesis pathway involved in protein folding and trafficking in a large number of biological recognition events, is required for α-amanitin toxicity. Using a virtual drug screening, they identified indocyanine green as an inhibitor of STT3B that may prevent liver toxicity. Indocyanine green was also found to increase the probability of survival of human cell lines and mice exposed to α-amanitin.

Further research is needed to understand the exact mechanisms indocyanine green uses to inhibit α-amanitin and assess its safety for use in humans. The authors also suggest that the method of combining genome-wide CRISPR screening with virtual drug screening could help to quickly identify new antidotes for other medically relevant human poisons.