Dna2 Helicase/Nuclease Causes Replicative Fork Stalling and Double-strand Breaks in the Ribosomal DNA of Saccharomyces cerevisiae

We have proposed that faulty processing of arrested replication forks leads to increases in recombination and chromosome instability in Saccharomyces cerevisiae and contributes to the shortened lifespan of dna2 mutants. Now we use the ribosomal DNA locus, which is a good model for all stages of DNA replication, to test this hypothesis. We show directly that DNA replication pausing at the ribosomal DNA replication fork barrier (RFB) is accompanied by the occurrence of double-strand breaks near the RFB. Both pausing and breakage are elevated in the early aging, hypomorphic dna2-2 helicase mutant. Deletion of FOB1, encoding the fork barrier protein, suppresses the elevated pausing and DSB formation, and represses initiation at rDNA ARSs. The dna2-2 mutation is synthetically lethal with {Delta}rrm3, encoding another DNA helicase involved in rDNA replication. It does not appear to be the case that the rDNA is the only determinant of genome stability during the yeast lifespan however since strains carrying deletion of all chromosomal rDNA but with all rDNA supplied on a plasmid, have decreased rather than increased lifespan. We conclude that the replication-associated defects that we can measure in the rDNA are symbolic of similar events occurring either stochastically throughout the genome or at other regions where replication forks move slowly or stall, such as telomeres, centromeres, or replication slow zones

Experimental Investigation of Thermal Cracking and Permeability Evolution of Granite with Varying Initial Damage under High Temperature and Triaxial Compression

Thermal cracking and permeability evolution of granite under high temperature and triaxial compression are the key to designing high-level waste disposal sites. In this paper, uniaxial compression tests of granite specimens with different axial compression are designed, and then a solid-head-designed coupling triaxial testing system is applied to study thermal cracking and permeability evolution of granite specimen with different damage at different inlet gas pressures (1, 2, 4, and 6 MPa) and temperatures (ranging from 100 to 650°C). The test results show that granite, nearly impermeable rocks, can show a striking increase of permeability by heating beyond the critical temperature. When the initial axial pressure is 60% or 70% of the uniaxial compressive strength, the growth of granite permeability exhibits three stages during 100∼650°C heating process. Permeability increases by two orders of magnitude, but it does not reach the maximum value (i.e., a network of interconnected cracks is not fully formed in the specimen). With increasing initial damage, permeability shows a sharp increase. Permeability increases by three orders of magnitude, it is in equilibrium state, and a network of interconnected cracks is fully formed in the specimen. Permeability of granite has a critical temperature at which permeability increases sharply. When the temperature is lower than the critical temperature, the magnitude of permeability is 10−18 m2 with a slight increase. When temperature is higher than the critical temperature, the magnitude of permeability is 10−15 m2 with a sharp increase. The critical temperature is related to the initial damage of specimen, and the critical temperature is smaller with the initial damage going larger. Therefore, studying thermal cracking and permeability evolution of granite with different initial damage under high temperature and triaxial compression is expected to provide necessary and valuable insight into the design and construction of high-level waste disposal structures

A Study of the Interaction between Cucurbit[7]uril and Alkyl Substituted 4-Pyrrolidinopyridinium Salts

The interaction between cucurbit[7]uril (Q[7]) and a series of 4-pyrrolidinopyridinium salts bearing aliphatic substituents at the pyridinium nitrogen, namely 4-(C4H8N)C5H5NRBr, where R = H (C0), Et (C2), n-butyl (C4), n-hexyl (C6), has been studied in aqueous solution by 1H NMR spectroscopy, electronic absorption spectroscopy, and mass spectrometry

P Systems based Computing Polynomials: Design and Formal Verification

Automatic design of P systems is an attractive research topic in the community of membrane computing. Differing from the previous work that used evolutionary algorithms to fulfill the task, this paper presents the design of a simple (deterministic transition) P system (without input membrane) of degree 1, capturing the value of the k- order (k 2) polynomial by using a reasoning method. Specifically, the values of polynomial p(n) corresponding to a natural number t is equal to the multiplicity of a distinguished object of the system (the output object) in the configuration at instant t. We also discuss the descriptive computational resources required by the designed k-order polynomial P system.Ministerio de Economía y Competitividad TIN2012-3743

Amino acid recognition by a fluorescent chemosensor based on cucurbit[8]uril and acridine hydrochloride

A new fluorescent chemosensor comprised of cucurbit[8]uril (Q[8]) and acridine hydrochloride (AC) has been designed and utilized for the recognition of amino acids. The AC was encapsulated by the Q[8] cavity and formed a 1:2 host-guest inclusion complex both in solution (aqueous) and in the solid-state. Whilst free AC is known to be strongly fluorescent, this strong fluorescence was quenched in the inclusion complex Q[8]-AC. This non-fluorescent complex Q[8]-AC was capable of serving as a fluorescence “off-on” probe, and was able to recognize either L-Phe or L-Trp via the competitive interaction between L-Phe or L-Trp. Moreover, the pH responsive nature of the probe allowed for the detection of basic amino acids, namely L-Arg, L-His, or L-Lys). As a result, a fluorescence method for the detection of five amino acids using a single system has been developed

A hemicyanine and cucurbit[n]uril inclusion complex: competitive guest binding of cucurbit[7]uril and cucurbit[8]uril

The interaction between the hemicyanine indole derivative H and the cucubit[n]urils Q[7] and Q[8] has been studied using 1H NMR and UV spectroscopy as well as by fluorescence experiments. Competitive studies on the inclusion of H by Q[7] and Q[8] have also been conducted, and reveal that on changing the size of the Q[n] cavity, the binding behaviour can be very different

Emma: An accurate, efficient, and multi-modality strategy for autonomous vehicle angle prediction

Autonomous driving and self-driving vehicles have become the most popular selection for customers for their convenience. Vehicle angle prediction is one of the most prevalent topics in the autonomous driving industry, that is, realizing real-time vehicle angle prediction. However, existing methods of vehicle angle prediction utilize only single-modal data to achieve model prediction, such as images captured by the camera, which limits the performance and efficiency of the prediction system. In this paper, we present Emma, a novel vehicle angle prediction strategy that achieves multi-modal prediction and is more efficient. Specifically, Emma exploits both images and inertial measurement unit (IMU) signals with a fusion network for multi-modal data fusion and vehicle angle prediction. Moreover, we design and implement a few-shot learning module in Emma for fast domain adaptation to varied scenarios (e.g., different vehicle models). Evaluation results demonstrate that Emma achieves overall 97.5% accuracy in predicting three vehicle angle parameters (yaw, pitch, and roll), which outperforms traditional single-modalities by approximately 16.7%–36.8%. Additionally, the few-shot learning module presents promising adaptive ability and shows overall 79.8% and 88.3% accuracy in 5-shot and 10-shot settings, respectively. Finally, empirical results show that Emma reduces energy consumption by 39.7% when running on the Arduino UNO board

A study of the interaction between cucurbit[8]uril and alkyl substituted 4-pyrrolidinopyridinium salts

The interaction between cucuribit[8]uril (Q[8]) and a series of 4-pyrrolidinopyridinium salts bearing aliphatic substituents at the pyridinium nitrogen, namely 4-(C4H8N)C5H5NRBr, where R = Et (g1), n-butyl (g2), n-pentyl (g3), n-hexyl (g4), n-octyl (g5), n-dodecyl (g6), has been studied in aqueous solution by 1H NMR spectroscopy, electronic absorption spectroscopy, Isothermal Titration Calorimetry and mass spectrometry. Single crystal X-ray diffraction revealed the structure of the host-guest complexes for g1, g2, g3, and g5. In each case the Q[8] contains two guest molecules in a centrosymmetric dimer. The orientation of the guest molecule changes as the alkyl chain increases in length. Interestingly, in the solid state, the inclusion complexes identified are different from those observed in solution, and furthermore, in the case of g3, Q[8] exhibits two different interactions with the guest. In solution, the length of the alkyl chain plays a significant role in determining the type of host-guest interaction present