Icosidodecahedral Coordination-Saturated Cuprofullerene.

The first coordination-saturated buckyball with a C60 molecule totally encased in an icosidodecahedral Cu30 in a (µ30 -(η2 )30 )-fashion, namely C60 @Cu30 @Cl36 N12 , has been successfully realized by a C60 -templated assembly. The 48 outmost coordinating atoms (36Cl+12N) comprise a new simple polyhedron that is described by a ccf topology. Charge transfer from (CuI , Cl) to C60 explains the expansion of the light absorption up to 700 nm, and accounts for an ultrafast photophysical process that underpins its high photothermal conversion efficiency. This work makes a giant step forward in exohedral metallofullerene (ExMF) chemistry.

Multicenter investigation of pediatric gastrointestinal tract magnets ingestion in China.

PURPOSE: To describe the incidence and management of gastrointestinal tract Buckyball magnets ingestions in a multicenter Chinese pediatric patient population, and discuss the preventive measures. METHODS: Medical records of 74 pediatric patients from 9 large Chinese hospitals during the past 10 years, who were diagnosed as buckyball magnets ingestion and got invasive treatment, were retrospectively studied. The follow-up was through telephone and outpatient service to estimate the post-surgery condition. Information collection was through online questionnaire. RESULTS: Among the 74 cases, there were 50 boys (68%) and 24 girls (32%). The median age was 36 (interquartile range (IQR) 22-77) months, with a range of 7 months to 11 years, and it showed two peaks, the first between 1 and 3 years, and the second between 6 to 11 years. The annual case number showed a sharp increase over time, and the total case number in the last 2 years (2017 and 2018) showed a greater than 9-fold increase when compared with the first 2 years (2013 and 2014). The majority of ingestions were unintentional, with only 3 patients deliberately swallowing the Buckyball magnets. The median time of ingestion until the onset of emergent symptoms was 2 (IQR 1-5) days, and ranged from 4 h to 40 days. Twenty-one patients had no symptoms, and the remaining cases presented with abdominal pain, vomiting, fever, abdominal distension, excessive crying, melena, and the ceasing of flatus and defecation. Gastroscopy, colonoscopy, laparoscopic surgery and laparotomy surgery were performed in accordance with the algorithm from the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN). Procedural and operative findings included gastrointestinal mucosa erosion, ischemia and necrosis, perforation, and abdominal abscess, fistula and intestinal obstruction. The median number of Buckyball magnets ingested was 4 (IQR 2-8), with a range from 1 to 39. During the median follow-up period of 6 (IQR 1-15) months, 3 patients had intestinal obstruction, and one underwent a second operation. The remaining 71 patients courses were uneventful during the follow-up period. None of the 74 patients reported a second swallowing of foreign bodies. CONCLUSIONS: The incidence of pediatric gastrointestinal tract magnets ingestion in China is increasing. Management of such patients should follow the NASPGHAN algorithm. Preventive measures to limit children's access to Buckyball magnets should be taken from three levels, namely the national administration, producer, and consumer.

Introducing a novel C50N10 azafullerene with chained nitrogen atoms on a buckyball pole: structure, stability, vibration, and electronic properties.

CONTEXT: Fullerenes are of high significance due to their unique chemical properties and various applications in technology, particularly materials science, drug delivery, electronics, and nanoelectronics. In the recent years, many attempts have been focused to introduce new heteroatom-doped fullerenes having advanced chemical properties and tunable electronic traits, which make them a potential candidate for application in many branches of sciences. In this study, a novel C50N10 azafullerene with a fascinating structure of chained nitrogen atoms on a buckyball pole, with different electronic and optical properties compared to its other analogs, is introduced and trace of N-N substructures on the surface of C60 fullerene cage is investigated. For this molecule, four structural isomers including 3 structures with chain N atoms on a fullerene buckyball pole (NP isomers) and one isomer with separated N atoms (SN isomer) have been studied. All isomers have been studied with and without symmetry constraints, and the symmetry influence on the structure and stability of each isomer has been investigated. Although the studied NP structures have lower stability than the SN isomer, some reasons (such as their more all-carbon hexagonal rings, breaking some of their N-N bonds for partial opening of the cage and creating bigger rings in order to get rid of the unfavorable strain, as well as decreasing the N-N lone pair repulsions) lead to the acceptable stability of these structures with the bonded N atoms. The results of atomization energy and vibrational frequency calculations indicate that isomers with the bonded N atoms have acceptable stabilities and do not decompose into their constituent components. Investigation on the structural parameters demonstrates important roles of the number of all-carbon hexagonal rings, the number of N-N junction, and the molecule symmetry in the stability of the structures with the bonded N atoms. Study on the electronic and optical properties indicates that the target structures exhibit high electronic polarizability, relatively small HOMO/LUMO gap, high first- and second-order hyperpolarizability, and also large third-order nonlinear optical properties. METHODS: All calculations have been performed using Gaussian G09 software using density functional theory (DFT) approach. Three-parameter Beck hybrid exchange functional (B3) hybridized with nonlocal correlation functional of Lee, Yang, and Parr (LYP) has been employed as the level of DFT calculations. All optimizations have been performed at double-zeta polarized (DZP) split valence 6-31G(d,p) and also at split valence TZP 6-311G(d,p) basis sets. The global minimum structures have been confirmed by frequency calculations at the same level of optimizations. The natural bond orbital (NBO) analyses, frontier orbital surfaces imaging, atomic charges, and charge transfer analyses have been achieved by GenNBO program package.

Density Functional Theory for Buckyballs within Symmetrized Icosahedral Basis.

We have developed a highly efficient computation method based on density functional theory (DFT) within a set of fully symmetrized basis functions for the C60 buckyball, which possesses the icosahedral (Ih) point-group symmetry with 120 symmetry operations. We demonstrate that our approach is much more efficient than the conventional approach based on three-dimensional plane waves. When applied to the calculation of optical transitions, our method is more than one order of magnitude faster than the existing DFT package with a conventional plane-wave basis. This makes it very convenient for modeling optical and transport properties of quantum devices related to buckyball crystals. The method introduced here can be easily extended to other fullerene-like materials.

Computational simulation-based study of novel ZnO Buckyball structures.

A novel Zinc Oxide Buckyball (ZnO-b) system has been optimized using the first principle density functional theory (DFT). The study of the structural, electronic, and optical properties of both the pristine and Al, Ga, and Ag-doped ZnO-b and ZnO-h (ZnO hexagonal) systems have been reported here. A comparative study of the variations which occurred due to changes in the crystal structure, dopant element as well as doping site was done for both systems. The study includes the structural analysis followed by the electronic analysis with the study of Density of States (DOS), Partial Density of States (PDOS), and at last the Optical analysis of the systems. The bandgap engineering due to structural variations in ZnO is observed here as metal-doped ZnO-h structures showed a vast shift towards a smaller bandgap value, showing enhancement in the metallic behaviour, while for ZnO-b it varied between 1.52 eV-2.94 eV with similar doping. It was observed that mostly the value of the cell volume and the bandgap decreases with an increase in the atomic radii of the dopant atoms due to quantum confinement effects. Ag-doped sample has shown a better optical conductivity with lower absorbance as compared to other dopants in the ZnO-b structure, which makes it a suitable material for optoelectronic applications. Overall, in the buckyball structures properties of dopants are predominating whereas, in hexagonal structures, properties of ZnO are predominating. This makes the ZnO-b structure a useful material for biomedical applications along with optoelectronic devices. This work also opens a wide area of study for applications of these novel structures from biomedicines to optoelectronic devices by precisely controlling their physical properties.

Simple, reliable, and universal metrics of molecular planarity.

Planarity is a very important structural character of molecules, which is closely related to many molecular properties. Unfortunately, there is currently no simple, universal, and robust way to measure molecular planarity. In order to fill this evident gap, we propose two metrics of molecular planarity, namely molecular planarity parameter (MPP) and span of deviation from plane (SDP), to quantitatively characterize planarity of molecules. MPP reflects the overall degree of deviation of the structure from a plane, while SDP represents the span of the structural deviation relative to the fitting plane; respectively, they are complementary to each other. The examples in this article demonstrate that these metrics have strong rationality and practicality. They can not only be used to investigate the planarity of the entire molecule, but also measure the planarity of local structures, and they can even be employed to study variation of molecular planarity during a dynamic process. In addition, we also propose a new representation, namely coloring atoms according to their signed deviation distance to the fitting plane. This kind of map allows researchers to intuitively and quickly recognize position of the atoms in the system relative to the fitting plane. It can be seen from the examples that this representation is very useful in graphically exhibiting molecular planarity. The methods proposed in this work have been implemented in our open-source analysis code Multiwfn, which can be freely obtained via http://sobereva.com/multiwfn . The use is very simple and rich file formats are supported as input file.

Germ cell differentiation requires Tdrd7-dependent chromatin and transcriptome reprogramming marked by germ plasm relocalization.

In many animal models, primordial germ cell (PGC) development depends on maternally deposited germ plasm, which prevents somatic cell fate. Here, we show that PGCs respond to regulatory information from the germ plasm in two distinct phases using two distinct mechanisms in zebrafish. We demonstrate that PGCs commence zygotic genome activation together with the somatic blastocysts with no demonstrable differences in transcriptional and chromatin opening. Unexpectedly, both PGC and somatic blastocysts activate germ-cell-specific genes, which are only stabilized in PGCs by cytoplasmic germ plasm determinants. Disaggregated perinuclear relocalization of germ plasm during PGC migration is regulated by the germ plasm determinant Tdrd7 and is coupled to dramatic divergence between PGC and somatic transcriptomes. This transcriptional divergence relies on PGC-specific cis-regulatory elements characterized by promoter-proximal distribution. We show that Tdrd7-dependent reconfiguration of chromatin accessibility is required for elaboration of PGC fate but not for PGC migration.

Surgical treatment of multiple magnet ingestion in children: A single-center study.

BACKGROUND: Since 2017, the number of magnet ingestion cases has increased year over year in our hospital. Almost all of the ingested magnetic foreign bodies were magnetic beads, and most of the patients experienced intestinal perforations, causing substantial damage. AIM: To summarize our experience with surgical treatment of multiple magnet ingestion in children. METHODS: The data for general surgeries were collected from January 2010 to April 2020, and the clinical characteristics, treatment methods, and outcomes were summarized and analyzed. Several typical cases were selected and discussed. RESULTS: Fifty-six cases of ingested magnetic foreign bodies were collected, of which 47 were magnetic beads. The average patient age was 4.7 ± 3.0 years old. The number of ingested magnetic foreign bodies ranged from 2 to 73. There were 26 cases with symptoms at the time of admission, including two cases of shock. Thirteen patients were discharged successfully following conservative treatment and 43 were treated by surgery. Laparotomy was the main method of operation. Laparoscopy was used in four cases, of which three were converted to open surgery, and one was treated successfully using surgery through the navel. Postoperative complications occurred in seven cases, incision infections were observed in six, and adhesive ileus was observed in one. CONCLUSION: Clinicians need to summarize their experiences with treating magnetic foreign body ingestions in detail and carry out clinical research to reduce the damage to children.

Visualizing the Balbiani Body in Zebrafish Oocytes.

Approaches to visualize the Balbiani body of zebrafish primary oocytes using protein, RNA, and mitochondrial markers are described. The method involves isolation, histology, staining, and microscopic examination of early zebrafish oocytes. These techniques can be applied to visualize gene products that are localized to the Balbiani body, and when applied to mutants can be used to decipher molecular and genetic pathways acting in Balbiani body development in early oocytes.

Interactions of calcium with the external surfaces of fullerenes and endofullerenes doped with radioactive sodium iodide.

We report first-principles calculations carried out to analyze the adsorption of calcium on the outer surface of the fullerene C60, yielding [C60 + mCa]. Geometric optimization (GO) and molecular dynamics (MD) simulation were performed using the plane-wave pseudopotential method within the framework of density functional theory (DFT) and time-dependent DFT (TD-DFT) to investigate the configurations, the associated energies in the ground state, and the stabilities of fullerenes and endofullerenes doped with radioactive sodium iodide when they interact with calcium atoms on the outer fullerene surface (i.e., [nNa131I@C60 + mCa]). The reason for investigating these calcium-functionalized (endo)fullerene systems was to gauge their potential stability when used as vectors to deliver radioiodine to cancerous tissue in the human body. In the simulations, we found that the geometric limit on the number of calcium atoms that can be physisorbed on the outer surface of an empty fullerene while maintaining its structural stability is 28 calcium atoms, which also takes into account the proportional expansion of the fullerene as the number of absorbed calcium atoms increases. However, the stability of a fullerene system during calcium adsorption also strongly depends on whether any atoms or molecules are being encapsulated by the fullerene, as these encapsulated atoms/molecules can also interact with the fullerene and influence its stability. A Mulliken electronegativity analysis revealed that, when atoms inside and/or outside the fullerene donate charge (electrons) to the fullerene, the fullerene expands. The excess charge on the carbon atoms of the fullerene weakens some of the carbon-carbon bonds, potentially causing them to break, in which case the fullerene loses its ability to encapsulate molecules and releases them. Graphical Abstract DFT simulation of a endo fullerene doped with radioactive sodium iodide interacting with 28 calcium atoms in a geometric arrangement.

Double-layer carbon nanocapsules with radioiodine content and its interaction with calcium, phosphorus, and strontium.

First principles calculations have been performed for C60@C180 carbon double-layer endofullerenes with up to: three diatomic radioiodine molecules (131I2), two potassium radio-iodide (K131I), and three sodium radio-iodide (Na131I) inside. The plane-wave pseudopotential (PP) method within the general gradient approximation (GGA) in the framework of the density functional theory (DFT) and time-dependent DFT (TD-DFT) was used to perform geometric optimizations (GOs) and molecular dynamics (MD) at 310 K and atmospheric pressure. We found that the double-layer carbon nanocapsules formed by two concentric fullerenes (C180 surrounding C60) are very stable and may contain a radiodosis, without altering their configuration; that is, the 3(131I2)@C60@C180, 2(K131I)@C60@C180, and 3(Na131I)@C60@C180 systems constitute stable nanocapsules. We analyzed the interaction of double-layer endofullerene with radioactive content with some calcium, phosphorus, and strontium atoms, [n(X131I)@C60@C180 + mY], for X = I, K, Na; Y = Ca, P, Sr; n = 1, 2, 3; m = 1, …, 20. Our calculations show that up to m = 20 calcium atoms can easily be physisorbed by the outer surface of the double-layer endofullerene, maintaining their integrity and shielding the radiodosis of any interaction that can proceed from the outside. It is thus concluded that these double-layer endofullerenes can be functionalized as vectors to deliver radiodosis with structural advantages over the single layer systems; as they are more robust, stable, and possess a larger surface to functionalize with some atoms serving as molecular recognizers. Graphical abstract Double-layer carbon nanocapsules with radioiodine content and its interaction with calcium, phosphorus and strontium.

Buckyball sandwiches.

Two-dimensional (2D) materials have considerably expanded the field of materials science in the past decade. Even more recently, various 2D materials have been assembled into vertical van der Waals heterostacks, and it has been proposed to combine them with other low-dimensional structures to create new materials with hybridized properties. We demonstrate the first direct images of a suspended 0D/2D heterostructure that incorporates C60 molecules between two graphene layers in a buckyball sandwich structure. We find clean and ordered C60 islands with thicknesses down to one molecule, shielded by the graphene layers from the microscope vacuum and partially protected from radiation damage during scanning transmission electron microscopy imaging. The sandwich structure serves as a 2D nanoscale reaction chamber, allowing the analysis of the structure of the molecules and their dynamics at atomic resolution.

Exploring Adsorption of Water and Ions on Carbon Surfaces using a Polarizable Force Field.

Graphene, carbon nanotubes, and fullerenes are of great interest due to their unique properties and diverse applications in biology, molecular electronics, and materials science. Therefore, there is demand for methods that can accurately model the interface between carbon surfaces and their environment. In this letter we compare results for complexes of water, potassium ion, and chloride ion with graphene, carbon nanotube, and fullerene surfaces using a standard non-polarizable force field (OPLS-AA), a polarizable force field (OPLS-AAP), DFT, and ab initio theory. For interactions with water, OPLS-AA with the TIP3P or TIP4P water models describes the interactions with benzene (C(6)H(6)) and coronene (C(24)H(12)) well; however, for acenes larger than circumcoronene (C(54)H(18)) and especially for C(60), the interaction energies are somewhat too weak and polarization is needed. For ions interacting with carbon surfaces, inclusion of polarization is essential, and OPLS-AAP is found to perform well in comparison to the highest-level quantum mechanical methods. Overall, OPLS-AAP provides an accurate and computationally efficient force field for modeling condensed-phase systems featuring carbon surfaces.