Classical force fields have been broadly used in studies of metal–organic framework crystals. However, processes involving bond breaking or forming are prohibited due to the nonreactive nature of the potentials. With emerging trends in the study of zeolitic imidazolate frameworks (ZIFs) that include glass formation, defect engineering, and chemical stability, enhanced computational methods are needed for efficient computational screening of ZIF materials. Here, we present simulations of three ZIF compounds using a ReaxFF reactive force field. By simulating the melt–quench process of ZIF-4, ReaxFF can reproduce the atomic structure, density, thermal properties, and pore morphology of the glass formed (a gZIF-4), showing remarkable agreement with experimental and first-principles molecular dynamics results. The predictive capability of ReaxFF is further exemplified in the melting of ZIF-62, where the balancing of electronic and steric effects of benzimidazolate yields a lower T m. On the basis of the electron-withdrawing effect of the −NO2 group, ReaxFF simulations predict that ZIF-77 has an even lower T m in terms of Zn–N interaction, but its low chemical stability makes it unsuitable as a glass former. Because of its low computational cost and transferability, ReaxFF will enable the computational design of ZIF materials by accounting for properties associated with disorder/defects.

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RING finger proteins comprise a large family and play key roles in regulating growth/developmental processes, hormone signaling and responses to biotic and abiotic stresses in plants. A rice gene, OsBIRF1, encoding a putative RING-H2 finger protein, was cloned and identified. OsBIRF1 encodes a 396 amino acid protein belonging to the ATL family characterized by a conserved RING-H2 finger domain (C-X2-C-X15-C-X1-H-X2-H-X2-C-X10-C-X2-C), a transmembrane domain at the N-terminal, a basic amino acid rich region and a characteristic GLD region. Expression of OsBIRF1 was up-regulated in rice seedlings after treatment with benzothaidiazole, salicylic acid, l-aminocyclopropane-1-carboxylic acid and jasmonic acid, and was induced differentially in incompatible but not compatible interactions between rice and Magnaporthe grisea, the causal agent of blast disease. Transgenic tobacco plants that constitutively express OsBIRF1 exhibit enhanced disease resistance against tobacco mosaic virus and Pseudomonas syringae pv. tabaci and elevated expression levels of defense-related genes, e.g. PR-1, PR-2, PR-3 and PR-5. The OsBIRF1-overexpressing transgenic tobacco plants show increased oxidative stress tolerance to exogenous treatment with methyl viologen and H2O2, and up-regulate expression of oxidative stress-related genes. Reduced ABA sensitivity in root elongation and increased drought tolerance in seed germination were also observed in OsBIRF1 transgenic tobacco plants. Furthermore, the transgenic tobacco plants show longer roots and higher plant heights as compared with the wild-type plants, suggesting that overexpression of OsBIRF1 promote plant growth. These results demonstrate that OsBIRF1 has pleiotropic effects on growth and defense response against multiple abiotic and biotic stresses.

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The most common translocation in childhood T-cell acute lymphoblastic leukemia (T-ALL) involves the LMO2 locus, resulting in ectopic expression of the LMO2 gene in human thymocytes. The LMO2 gene was also activated in patients with X-linked Severe Combined Immune Deficiency treated with gene therapy because of retroviral insertion in the LMO2 locus. The LMO2 insertions predisposed these children to T-ALL, yet how LMO2 contributes to T cell transformation remains unclear. The LIM (Lin 11, Isl-1, Mec-3) domain containing LMO2 protein regulates erythropoiesis as part of a large transcriptional complex consisting of LMO2, TAL1, E47, GATA1 and LDB1 that recognizes bipartite E-box-GATA1 sites on target genes. Similarly, a TAL1/E47/LMO2/LDB1 complex is observed in human T-ALL and Tal1 and Lmo2 expression in mice results in disease acceleration. To address the mechanism(s) of Tal1/Lmo2 synergy in leukemia, we generated Lmo2 transgenic mice and mated them with mice that express wild-type Tal1 or a DNA-binding mutant of TAL1. Tal1/Lmo2 and MutTAL1/Lmo2 bitransgenic mice exhibit perturbations in thymocyte development due to reduced E47/HEB transcriptional activity and develop leukemia with identical kinetics. These data demonstrate that the DNA-binding activity of Tal1 is not required to cooperate with Lmo2 to cause leukemia in mice and suggest that Lmo2 may cooperate with Tal1 to interfere with E47/HEB function(s).

A topological constraint model is developed to predict the compositional scaling of glass transition temperature (T g) in a metal–organic framework glass, a gZIF-62 [Zn­(Im2–x bIm x )]. A hierarchy of bond constraints is established using a combination of experimental results and molecular dynamic simulations with ReaxFF. The model can explain the topological origin of T g as a function of the benzimidazolate concentration with an error of 3.5 K. The model is further extended to account for the effect of 5-methylbenzimidazolate, enabling calculation of a ternary diagram of T g with a mixture of three organic ligands in an as-yet unsynthesized, hypothetical framework. We show that topological constraint theory is an effective tool for understanding the properties of metal–organic framework glasses.

We examine the mean relaxation time predicted by the Maxwell relation for stress and structural α‐relaxation phenomena. We express this relation using the Markov network framework and present an expression for the average relaxation time under equilibrium and nonequilibrium conditions that is rooted in the energy landscape of a material. We show that structural relaxation times calculated using the Maxwell relation must systematically underpredict the relaxation time. Finally, we report experimental evidence suggesting that the relaxation time obtained from shear viscosity measurements must correspond to a stress relaxation time.