Seroprevalence and risk factors of Toxoplasma gondii infection in children with leukemia in Shandong Province, Eastern China: a case—control prospective study

Limited information is available concerning the epidemiology of Toxoplasma gondii infection in children with leukemia in Eastern China. Therefore, a case-control study was conducted to estimate the seroprevalence of toxoplasmosis in this patient group and to identify risk factors and possible routes of infection. Serum samples were collected from 339 children with leukemia and 339 age matched health control subjects in Qingdao from September 2014 to March 2018. Enzyme linked immunoassays were used to screen anti- T. gondii IgG and anti- T. gondii IgM antibodies. Forty-eight (14.2%) children with leukemia and 31 (9.1%) control subjects were positive for anti-T. gondii IgG antibodies (P < 0.05), while 13 (3.8%) patients and 14 (4.1%) controls were positive for anti-T. gondii IgM antibodies (P = 0.84). Multivariate analysis showed exposure to soil and a history of blood transfusion were risk factors for T. gondii infection. Compared with IgG, patients with a history of blood transfusion were more likely to present anti- T. gondii IgM (P = 0.003). Moreover, patients with chronic lymphocytic leukemia and acute lymphocytic leukemia had higher T. gondii seroprevalence in comparison to control subjects (P = 0.002 and P = 0.016, respectively). The results indicated that the seroprevalence of T. gondii infection in children with leukemia is higher than that of healthy children in Eastern China. This information may be used to guide future research and clinical management, and further studies are necessary to elucidate the role of T. gondii in children with leukemia

Single crystal of a one-dimensional metallo-covalent organic framework.

Although polymers have been studied for well over a century, there are few examples of covalently linked polymer crystals synthesised directly from solution. One-dimensional (1D) covalent polymers that are packed into a framework structure can be viewed as a 1D covalent organic framework (COF), but making a single crystal of this has been elusive. Herein, by combining labile metal coordination and dynamic covalent chemistry, we discover a strategy to synthesise single-crystal metallo-COFs under solvothermal conditions. The single-crystal structure is rigorously solved using single-crystal electron diffraction technique. The non-centrosymmetric metallo-COF allows second harmonic generation. Due to the presence of syntactic pendant amine groups along the polymer chains, the metallopolymer crystal can be further cross-linked into a crystalline woven network

Data Release of the AST3-2 Automatic Survey from Dome A, Antarctica

AST3-2 is the second of the three Antarctic Survey Telescopes, aimed at wide-field time-domain optical astronomy. It is located at Dome A, Antarctica, which is by many measures the best optical astronomy site on the Earth's surface. Here we present the data from the AST3-2 automatic survey in 2016 and the photometry results. The median 5$\sigma$ limiting magnitude in $i$-band is 17.8 mag and the light curve precision is 4 mmag for bright stars. The data release includes photometry for over 7~million stars, from which over 3,500 variable stars were detected, with 70 of them newly discovered. We classify these new variables into different types by combining their light curve features with stellar properties from surveys such as StarHorse.Comment: 16 pages, 20 figures, accepted for publication in MNRA

Exoplanets in the Antarctic Sky I. The first data release of AST3-II (CHESPA) and new found variables within the southern CVZ of TESS

Located at Dome A, the highest point of the Antarctic plateau, the Chinese Kunlun station is considered to be one of the best ground-based photometric sites because of its extremely cold, dry, and stable atmosphere. A target can be monitored from there for over 40 days without diurnal interruption during a polar winter. This makes Kunlun station a perfect site to search for short-period transiting exoplanets. Since 2008, an observatory has existed at Kunlun station, and three telescopes are working there. Using these telescopes, the AST3 project has been carried out over the last 6 yr with a search for transiting exoplanets as one of its key programs (CHESPA). In the austral winters of 2016 and 2017, a set of target fields in the southern continuous viewing zone (CVZ) of TESS were monitored by the AST3-II telescope. In this paper, we introduce the CHESPA and present the first data release containing photometry of 26,578 bright stars (m(i) <= 15). The best photometric precision at the optimum magnitude for the survey is around 2 mmag. To demonstrate the data quality, we also present a catalog of 221 variables with a brightness variation greater than 5 mmag from the 2016 data. Among these variables, 179 are newly identified periodic variables not listed in the AAVSO database (https://www.aavso.org/), and 67 are listed in the Candidate Target List. These variables will require careful attention to avoid false-positive signals when searching for transiting exoplanets. Dozens of new transiting exoplanet candidates will be released in a subsequent paper

Exoplanets in the Antarctic Sky. II. 116 Transiting Exoplanet Candidates Found by AST3-II (CHESPA) within the Southern CVZ of TESS

We report first results from the CHinese Exoplanet Searching Program from Antarctica (CHESPA)-a wide-field high-resolution photometric survey for transiting exoplanets carried out using telescopes of the AST3 (Antarctic Survey Telescopes times 3) project. There are now three telescopes (AST3-I, AST3-II, and CSTAR-II) operating at Dome A-the highest point on the Antarctic Plateau-in a fully automatic and remote mode to exploit the superb observing conditions of the site, and its long and uninterrupted polar nights. The search for transiting exoplanets is one of the key projects for AST3. During the austral winters of 2016 and 2017 we used the AST3-II telescope to survey a set of target fields near the southern ecliptic pole, falling within the continuous viewing zone of the TESS mission. The first data release of the 2016 data, including images, catalogs, and light curves of 26,578 bright stars (7.5 <= m(i) <= 15), was presented in Zhang et al. The best precision, as measured by the rms of the light curves at the optimum magnitude of the survey (m(i) = 10), is around 2 mmag. We detect 222 objects with plausible transit signals from these data, 116 of which are plausible transiting exoplanet candidates according to their stellar properties as given by the TESS Input Catalog, Gaia DR2, and TESS-HERMES spectroscopy. With the first data release from TESS expected in late 2018, this candidate list will be timely for improving the rejection of potential false-positives

Site-Specific Internal Motions in GB1 Protein Microcrystals Revealed by 3D ²H–¹³C–¹³C Solid-State NMR Spectroscopy

²H quadrupolar line shapes deliver rich information about protein dynamics. A newly designed 3D ²H–¹³C–¹³C solid-state NMR magic angle spinning (MAS) experiment is presented and demonstrated on the microcrystalline β1 immunoglobulin binding domain of protein G (GB1). The implementation of ²H–¹³C adiabatic rotor-echo-short-pulse-irradiation cross-polarization (RESPIRATION CP) ensures the accuracy of the extracted line shapes and provides enhanced sensitivity relative to conventional CP methods. The 3D ²H–¹³C–¹³C spectrum reveals ²H line shapes for 140 resolved aliphatic deuterium sites. Motional-averaged ²H quadrupolar parameters obtained from the line-shape fitting identify side-chain motions. Restricted side-chain dynamics are observed for a number of polar residues including K13, D22, E27, K31, D36, N37, D46, D47, K50, and E56, which we attribute to the effects of salt bridges and hydrogen bonds. In contrast, we observe significantly enhanced side-chain flexibility for Q2, K4, K10, E15, E19, N35, N40, and E42, due to solvent exposure and low packing density. T11, T16, and T17 side chains exhibit motions with larger amplitudes than other Thr residues due to solvent interactions. The side chains of L5, V54, and V29 are highly rigid because they are packed in the core of the protein. High correlations were demonstrated between GB1 side-chain dynamics and its biological function. Large-amplitude side-chain motions are observed for regions contacting and interacting with immunoglobulin G (IgG). In contrast, rigid side chains are primarily found for residues in the structural core of the protein that are absent from protein binding and interactions

Grafting Molecular Cobalt‐oxo Cubane Catalyst on Polymeric Carbon Nitride for Efficient Photocatalytic Water Oxidation

In this work, we have successfully constructed a cobalt-oxo (CoIII4 O4 ) cubane complex on polymeric carbon nitride (PCN) through pyridine linkage. The covalently grafted CoIII4 O4 cubane units were uniformly distributed on the PCN surface. The product exhibited greatly enhanced photocatalytic activities for water oxidation under visible-light irradiation. Further characterizations and spectroscopic analyses revealed that the grafted CoIII4 O4 cubane units could effectively capture the photogenerated holes from excited PCN, lower the overpotential of oxygen evolution reaction (OER), and serve as efficient catalysts to promote the multi-electron water oxidation process. This work provides new insight into the future development of efficient photocatalysts by grafting molecular catalysts for artificial photosynthesis.Ministry of Education (MOE)Accepted versionThis work is supported by the Ministry of Education, Singapore, under AcRF-Tier2 (MOE2018-T2-1-017) and AcRF-Tier1 (MOE2019-T1-002-012, RG102/19). The authors also thank the support from NTU seed funding for Solar Fuels Laboratory

Solid-state NMR 13C, 15N assignments of human histone H3 in the nucleosome core particle

Nucleosome core particle (NCP), the basic unit of chromatin in eukaryotic cells, consists of ~ 147 bp DNA wrapped around a histone octamer (HO) formed by two H2A–H2B dimers and one (H3–H4)2 tetramer. Histones undergo various post-translational modifications (PTMs), which regulates genomic activities in different cellular phases. High-resolution structures have been solved for many nucleosomes primarily including NCPs. However, the atomic-resolution structures of nucleosome arrays and chromatin fiber, as well as the dynamics of nucleosomes remain poorly understood. Solid-state NMR (SSNMR) is one of the premier techniques to answer these questions. In this study, we present the 13C and 15N chemical shifts assignments for the globular domain of human histone H3 (hH3) using multidimensional SSNMR experiments. The obtained spectra are of outstanding resolution and the assignments are nearly 100% complete for the backbone 13C and 15N spins of R42–G132 and ~ 80% when taking into account the side chains. The secondary structure derived from the chemical shifts agrees with the previously reported X-ray crystal structure. The reported chemical shifts can be carried over to future SSNMR studies of structure and dynamics of hH3 in NCPs, nucleosome array, chromatin fibers and nucleosome-protein complexes.Ministry of Education (MOE)Accepted versionThis work was supported by the Singapore Ministry of Education (MOE) Academic Research Fund (AcRF) Tier 2 (MOE2018-T2-1-112) and Tier 3 grants (MOE2012-T3-1-001)