ALBERT

Description: Environmental stresses and nutrition availability critically affect animal development. Numerous animal species across multiple phyla enter developmental arrest for long-term survival in unfavorable environments and resume development upon stress removal. Here we show that compromising overall microRNA (miRNA) functions or mutating certain individual miRNAs impairs the long-term survival of nematodes during starvation-induced L1 diapause. We provide evidence that miRNA miR-71 is not required for the animals’ entry into L1 diapause, but plays a critical role in long-term survival by repressing the expression of insulin receptor/PI3K pathway genes and genes acting downstream or in parallel to the pathway. Furthermore, miR-71 plays a prominent role in developmental recovery from L1 diapause partly through repressing the expression of certain heterochronic genes. The presented results indicate that interactions between multiple miRNAs and likely a large number of their mRNA targets in multiple pathways regulate the response to starvation-induced L1 diapause.

Description: Extensive studies have suggested that most miRNA functions are executed through complex miRNA-target interaction networks, and such networks function semiredundantly with other regulatory systems to shape gene expression dynamics for proper physiological functions. We found that knocking down vgln-1 , which encodes a conserved RNA-binding protein associated with diverse functions, causes severe larval arrest at the early L1 stage in animals with compromised miRISC functions (an ain-2 /GW182 mutant). Through an enhancer screen, we identified five specific miRNAs, and miRNA families, that act semiredundantly with VGLN-1 to regulate larval development. By RIP-Seq analysis, we identified mRNAs that are directly bound by VGLN-1 , and highly enriched for miRNA binding sites, leading to a hypothesis that VGLN-1 may share common targets with miRNAs to regulate gene expression dynamics for development.

Description: We report a Danio rerio transposon named DrTRT , for D. rerio Transposon Related to Tc1 . The complete sequence of the DrTRT transposon is 1,563 base pairs (bp) in length, and its transposase putatively encodes a 338-amino acid protein that harbors a DD37E motif in its catalytic domain. We present evidence based on searches of publicly available genomes that TRT elements commonly occur in vertebrates and protozoa. Phylogenetic and functional domain comparisons confirm that TRT constitutes a new subfamily within the Tc1 family. Hallmark features of having no premature termination codons within the transposase, the presence of all expected functional domains, and its occurrence in the bony fish transcriptome suggest that TRT might have current or recent activity in these species. Further analysis showed that the activity of TRT elements in these species might have arisen about between 4 and 19 Ma. Interestingly, our results also implied that the widespread distribution of TRT among fishes, frog, and snakes is the result of multiple independent HT events, probably from bony fishes to snakes or frog. Finally, the mechanisms underlying horizontal transfer of TRT elements are discussed.

Description: While vertical stacking of quantum well and dot structures is well established in heteroepitaxial semiconductor materials, manipulation of quantum barriers in the lateral directions poses a significant engineering challenge. Here, we demonstrate lateral quantum barrier manipulation in a crystalline SiGe alloy using structured mechanical fields to drive compositional redistribution. To apply stress, we make use of a nano-indenter array that is pressed against a Si 0.8 Ge 0.2 wafer in a custom-made mechanical press. The entire assembly is then annealed at high temperatures, during which the larger Ge atoms are selectively driven away from areas of compressive stress. Compositional analysis of the SiGe substrates reveals that this approach leads to a transfer of the indenter array pattern to the near-surface elemental composition, resulting in near 100% Si regions underneath each indenter that are separated from each other by the surrounding Si 0.8 Ge 0.2 bulk. The “stress transfer” process is studied in detail using multiscale computer simulations that demonstrate its robustness across a wide range of applied stresses and annealing temperatures. While the “Si nanodot” structures formed here are not intrinsically useful as quantum structures, it is anticipated that the stress transfer process may be modified by judicious control of the SiGe film thickness and indenter array pattern to form more technologically useful structures.

Description: Direct simulation of a model with a large state space will generate enormous volumes of data, much of which is not relevant to the questions under study. In this paper, we consider a molecular self-assembly model as a typical example of a large state-space model, and present a method for selectively retrieving ‘target information’ from this model. This method partitions the state space into equivalence classes, as identified by an appropriate equivalence relation. The set of equivalence classes H , which serves as a reduced state space, contains none of the superfluous information of the original model. After construction and characterization of a Markov chain with state space H , the target information is efficiently retrieved via Markov chain Monte Carlo sampling. This approach represents a new breed of simulation techniques which are highly optimized for studying molecular self-assembly and, moreover, serves as a valuable guideline for analysis of other large state-space models.

Description: Theoretical modelling of the evolution of classical and recurrent novae plays an important role in studies of binary evolution, nucleosynthesis and accretion physics. However, from a theoretical perspective the observed statistical properties of novae remain poorly understood. In this paper, we have produced model populations of novae using a hybrid binary population synthesis approach for differing star formation histories (SFHs): a starburst case (elliptical-like galaxies), a constant star formation rate case (spiral-like galaxies) and a composite case (in line with the inferred SFH for M31). We found that the nova rate at 10 Gyr in an elliptical-like galaxy is ~10–20 times smaller than a spiral-like galaxy with the same mass. The majority of novae in elliptical-like galaxies at the present epoch are characterized by low-mass white dwarfs (WDs), long decay times, relatively faint absolute magnitudes and long recurrence periods. In contrast, the majority of novae in spiral-like galaxies at 10 Gyr have massive WDs, short decay times, are relatively bright and have short recurrence periods. The mass-loss time distribution for novae in our M31-like galaxy is in agreement with observational data for Andromeda. However, it is possible that we underestimate the number of bright novae in our model. This may arise in part due to the present uncertainties in the appropriate bolometric correction for novae.

Description: Activity of the RNA ligase RtcB has only two known functions: tRNA ligation after intron removal and XBP1 mRNA ligation during activation of the unfolded protein response. Here, we show that RtcB acts in neurons to inhibit axon regeneration after nerve injury. This function of RtcB is independent of its...

Description: Measurements of radiated power in magnetically confined plasmas are important for exhaust studies in present experiments and expected to be a critical diagnostic for future fusion reactors. Resistive bolometer sensors have long been utilized in tokamaks and helical devices but suffer from electromagnetic interference (EMI). Results are shown from initial testing of a new bolometer concept based on fiber-optic temperature sensor technology. A small, 80 μm diameter, 200 μm long silicon pillar attached to the end of a single mode fiber-optic cable acts as a Fabry–Pérot cavity when broadband light, λ o ∼ 1550 nm, is transmitted along the fiber. Changes in temperature alter the optical path length of the cavity primarily through the thermo-optic effect, resulting in a shift of fringes reflected from the pillar detected using an I-MON 512 OEM spectrometer. While initially designed for use in liquids, this sensor has ideal properties for use as a plasma bolometer: a time constant, in air, of ∼150 ms, strong absorption in the spectral range of plasma emission, immunity to local EMI, and the ability to measure changes in temperature remotely. Its compact design offers unique opportunities for integration into the vacuum environment in places unsuitable for a resistive bolometer. Using a variable focus 5 mW, 405 nm, modulating laser, the signal to noise ratio versus power density of various bolometer technologies are directly compared, estimating the noise equivalent power density (NEPD). Present tests show the fiber-optic bolometer to have NEPD of 5-10 W/m 2 when compared to those of the resistive bolometer which can achieve

Description: Late Ordovician (ca. 451 Ma) calc-alkaline adakitic granodiorite and granite, associated with coeval S-type granites, were discovered in the Central Tianshan block, NW China. They are characterized by high Sr (526–620 ppm), but low Y (6.8–8.6 ppm) and heavy rare earth element (HREE) contents (e.g., Yb = 0.7–0.8 ppm), and thus have high Sr/Y (66–86) ratios. The granodiorite has SiO 2 of 69.3 wt%, MgO of 1.4 wt%, and Mg# of 48, exhibiting light (L) REE–enriched patterns ([La/Yb] N = 15.82, [Dy/Yb] N = 1.25) with strong positive Eu (Eu = 1.65) but weak negative Nb, Ta, and Ti anomalies. Its low Cr (9.0 ppm) and Ni (6.2 ppm) concentrations, low negative Hf ( t ) and Nd ( t ) values (–11.3 to –5.0 and –4.8, respectively), old one-stage Nd model age (ca. 1.4 Ga), and high initial 87 Sr/ 86 Sr ratio (0.7129) are characteristics of derivation from the partial melting of thickened ancient lower crust, most likely in the eclogite facies. The adakitic granite samples contain slightly higher SiO 2 (72.4–73.0 wt%), but lower MgO (0.6–0.7 wt%) and Mg# (37–40), with low Cr (7.9–12.1 ppm) and Ni (5.6–7.4 ppm), displaying concave-upward REE patterns ([La/Yb] N = 19.25–30.01, [Dy/Yb] N = 0.85–1.01) with negligible Eu (Eu = 0.87–1.03) and pronounced negative Nb, Ta, and Ti anomalies. Their positive Hf ( t ) (+4.3 to +7.1) and Nd ( t ) (+1.6 to +3.2) values, young one-stage Nd model ages (0.9–0.8 Ga), and low initial 87 Sr/ 86 Sr ratios (0.7055–0.7060) indicate generation by the partial melting of relatively juvenile lower crust, probably in the garnet-bearing amphibolite facies. Combined with previous investigations, we suggest that the Central Tianshan developed as a continental arc along northern Tarim, facing the southward subduction of the Junggar oceanic plate during Ordovician time. Lower-crustal melting was likely induced by asthenosphere upwelling in response to rollback of the Junggar oceanic slab, accompanied by crustal extension and incipient opening of the South Tianshan back-arc basin along northern Tarim and separation of the Central Tianshan as a microcontinent. The heat brought by the ascending adakitic magmas possibly caused anatexis of the basement rocks, forming the coeval pelite-derived S-type granites. The eastern segment of the South Tianshan Ocean was most probably closed prior to ca. 380 Ma. This study provides ample evidence that adakitic rocks can be produced by partial melting of (thickened) lower crust during incipient opening of a back-arc basin.

Description: The correlations between intramyocellular lipid (IMCL), decreased fatty acid oxidation (FAO), and insulin resistance have led to the hypothesis that impaired FAO causes accumulation of lipotoxic intermediates that inhibit muscle insulin signaling. Using a skeletal muscle-specific carnitine palmitoyltransferase-1 KO model, we show that prolonged and severe mitochondrial FAO inhibition results...