When replication forks stall at damaged bases or upon nucleotide depletion, the intra-S phase checkpoint ensures they are stabilized and can restart. In intra-S checkpoint-deficient budding yeast, stalling forks collapse, and ∼10% form pathogenic chicken foot structures, contributing to incomplete replication and cell death (Lopes et al., 2001; Sogo et al., 2002; Tercero and Diffley, 2001). Using fission yeast, we report that the Cds1(Chk2) effector kinase targets Dna2 on S220 to regulate, both in vivo and in vitro, Dna2 association with stalled replication forks in chromatin. We demonstrate that Dna2-S220 phosphorylation and the nuclease activity of Dna2 are required to prevent fork reversal. Consistent with this, Dna2 can efficiently cleave obligate precursors of fork regression-regressed leading or lagging strands-on model replication forks. We propose that Dna2 cleavage of regressed nascent strands prevents fork reversal and thus stabilizes stalled forks to maintain genome stability during replication stress.

No abstract

A thermal analysis of lithium‐ion batteries during charge/discharge and thermal runaway has been carried out with a mathematical model. The main concern with the thermal behavior of the room temperature batteries is the possible significant temperature increase which may cause thermal runaway. The emphases of this work include the examination of the effects of battery design parameters and operating conditions on temperature rise/profile during normal battery operation and the evaluation of the possibility of the occurrence of thermal runaway due to battery abuse.

Because of the severe risk of oil pollution and increasing concerns about the sustainability of sorbent materials, there are considerable interests across the world to develop cost-effective, reusable, and environmentally friendly oil sorbents derived from renewable resources. Nanocellulose is a new family of promising cellulosic materials with a cellulose fibril width in the order of nanometer range (i.e., 2−100 nm). As a class of newly developed cellulose aerogels, nanocellulosederived ones combine intriguing interconnected three-dimensional porous characteristics of aerogel-type materials such as high porosity, large surface area, and low density with fascinating advantages related to naturally occurring nanocellulose: impressive mechanical properties, abundant sources, natural renewability, excellent biodegradability, and ease to surface modification. Therefore, nanocellulose-based aerogels are very ideal "green" oil sorbents after either appropriate hydrophobic modifications or carbonization. This present review summarizes the state-of-the-art in the aerogel-type oil sorbents derived from nanocellulose, including hydrophobized nanofibrillated cellulose (NFC)-based aerogels, hydrophobized bacterial cellulose (BC)-based ones, and the carbon ones prepared through the pyrolysis NFC or BC aerogels. Their respective preparation methods, structure, and oil-absorption performance are summarized. And the existing problems in the current research and the future development perspectives are also presented.

Mathematical modeling of heat generation and transport in lithium/polymer-electrolyte batteries for electric vehicle applications has been conducted. The results demonstrate that thermal management may not be a serious problem for batteries under low discharge rates. However, under high discharge rates, the temperature of a battery may increase remarkably if the thickness of a cell stack exceeds a certain value. Also, due to the low thermal conductivity of the polymer, the improvement of cooling conditions is not an effective means of improving heat removal for large-stack systems. For a required operational temperature range and a given discharge rate, model predictions can be used to design appropriate battery structures and to choose a suitable cooling scheme.

SignificanceCrops carrying broad-spectrum resistance loci provide an effective strategy for controlling infectious disease. Despite their importance, few broad-spectrum resistance loci have been reported, and the underlying mechanisms controlling the trait remain largely unknown. This report describes the identification of a gene, called “bsr-k1,” conferring broad-spectrum resistance and demonstrates that the encoded protein regulates immunity-related genes. Loss of function of BSR-K1 in rice leads to enhanced broad-spectrum resistance to two serious rice diseases with no major penalty on yield. This report provides insights into broad-spectrum resistance and offers an efficient strategy to breeding durably resistant rice.

A three-dimensional model is developed to simulate and compare heat generation and transport within a lithium polymer electrolyte battery under galvanostatic discharges and a dynamic power profile [the Simplified Federal Urban Driving Schedule (SFUDS)]. Emphasis is placed on the maintenance of the operational temperature and temperature uniformity within a battery by designing a suitable thermal management system. The results indicate that the anisotropic thermal conductivity within the battery is an important factor influencing thermal performance and should be taken into consideration in battery design. On the one hand, because of the low effective thermal conductivity across a laminated cell stack, steep temperature distributions may be caused if cooling channels or electric heaters are placed at the two ends of a cell stack. On the other hand, the relatively large average thermal conductivity along the width and height directions allows more efficient heat removal or addition, and thus facilitates the maintenance of uniform operating temperature. Under the SFUDS power profile, the time-averaged heat generation rate is low, and therefore a high-performance insulation material is required to maintain the operating temperature. The thermal model has been applied to study the effectiveness of different arrangements of cooling channels and electric heaters and to select suitable heating intensities and insulating materials.

The histone methyltransferase Mixed Lineage Leukemia (MLL) is essential to maintain hematopoietic stem cells and is a leukemia protooncogene. Although clustered homeobox genes are well-characterized targets of MLL and MLL fusion oncoproteins, the range of Mll -regulated genes in normal hematopoietic cells remains unknown. Here, we identify and characterize part of the Mll -dependent transcriptional network in hematopoietic stem cells with an integrated approach by using conditional loss-of-function models, genomewide expression analyses, chromatin immunoprecipitation, and functional rescue assays. The Mll -dependent transcriptional network extends well beyond the previously appreciated Hox targets, is comprised of many characterized regulators of self-renewal, and contains target genes that are both dependent and independent of the MLL cofactor, Menin. Interestingly, PR-domain containing 16 emerged as a target gene that is uniquely effective at partially rescuing Mll -deficient hematopoietic stem and progenitor cells. This work highlights the tissue-specific nature of regulatory networks under the control of MLL/Trithorax family members and provides insight into the distinctions between the participation of MLL in normal hematopoiesis and in leukemia.