Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

The persistent shadow of the supermassive black hole of M 87

In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3−3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30° relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5 × 109 M⊙. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet

Thermal Degradation and Stability of Accelerated-curing Phenol-formaldehyde Resin

In order to study the thermal stability of accelerated-curing PF resin, the curing behavior of fresh PF resin was investigated in the presence of single accelerator of methylolurea derivatives (MMU), magnesium hydrate (Mg(OH)2), 25% aqueous solution of sodium carbonate (Na2CO3), and propylene carbonate (PC). Also their optimum combination was added in fresh PF resin. The thermal stability of cured phenol-formaldehyde (PF) resins was studied using thermogravimetric analysis TG/DTA in air with heating rates of 5, 10, 15, and 20 °C min-1. Thermal degradation kinetics were investigated using the Kissinger and Flynn-Wall-Ozawa methods. The results show that these accelerators can promote fresh PF resin fast curing, and the degradation of accelerated-curing cured PF resin can be divided into three stages. Single accelerator MMU, Mg(OH)2, and Na2CO3 can promote fresh PF curing at low temperatures in the first stage, while the structure of PF resin which was added with MMU and PC was more rigid, according to thermal degradation kinetics. A novel fast curing agent which is compound with MMU+Na2CO3 for PF resin is proposed; not only can it maintain the advantage of fast curing of the single accelerator Na2CO3, but it also improves the thermal stability of PF resin

Biochar derived from traditional Chinese medicine residues: An efficient adsorbent for heavy metal Pb(II)

Biochar (BC) is widely used in the remediation of soil and wastewater polluted by heavy metals, but there are few reports on the characteristics of biochar derived via pyrolysis from different traditional Chinese medicine residues (TCMRs). In this study, biochars were prepared by slow pyrolysis of five common Chinese medicine residues, namely, Salvia miltiorrhiza (DNS), Ligusticum striatum (CX), Angelica sinensis (DG), Codonopsis pilosula (DGS), and Astragalus membranaceus (HQ). The biochars were systematically investigated by determining their physicochemical properties and using common characterization techniques. The Spearman correlation matrix between factors was used to examine relationships between properties of different biochars. Batch adsorption experiments were carried out to investigate the adsorption characteristics of biochar on Pb(II) and the mechanisms involved. The results showed that the physicochemical properties and adsorption performance of biochar were related to the type of its pharmaceutical residue. Biochar produced from materials with higher lignin content showed a better adsorption of the heavy metal Pb(II). All biochars were alkaline, with yields ranging from 29.30 to 38.65 %, and the main structure comprised of mesopores and macropores. The FT-IR and Boehm experiments revealed that the various TCMR biochars contained comparable functional groups, but their content varied. XRD and TEM results show that all biochar is amorphous with a crystalline structure, with the surface dominated by cellulose crystals and graphitic carbon. The O/C ratio ( 0.99), and their isotherms were consistent with the Langmuir model (R2 > 0.99), indicating a monolayer chemisorption process. The biochar samples exhibited varying adsorption capacities for Pb(II), with the highest capacity observed for BDNS (36.42 mg/g). The adsorption mechanism mainly involved precipitation, complexation with oxygen-containing functional groups, and ion exchange. This study indicates that biochars from herbal residues exhibit promising potential for adsorbing heavy metal Pb(II), suggesting biochar production as a viable method for recycling herbal residues

Foundations for Self-Determination in Early Childhood: An Inclusive Model for Children with Disabilities

This article introduces the Early Childhood Foundations Model for Self-Determination and provides a rationale for the need to consider the foundations of self-determination behavior that begin early in life. This model is based on the premise that young children with disabilities benefit from a collaborative partnership between important adults in the lives of children to provide a supportive, stimulating, and coordinated environment between inclusive classrooms and home settings. Within partnership, the Foundations Model establishes the proposition that the basic foundational skills for developing self-determination in later life require young children with disabilities to gain skills in (a) choice-making and problem solving, (b) self-regulation, and (c) engagement. In this position paper, the authors review literature related to these three foundational constructs and present a rationale for use of the Foundations Model as a guide to developing systematic interventions to start young students with disabilities on the road to building a foundation for self-determination