Protection from muscle damage in the absence of changes in muscle mechanical behavior

Introduction: The repeated bout effect characterizes the protective adaptation after a single bout of unaccustomed eccentric exercise that induces muscle damage. Sarcomerogenesis and increased tendon compliance have been suggested as potential mechanisms for the repeated bout effect by preventing muscle fascicles from being stretched onto the descending limb of the length–tension curve (the region where sarcomere damage is thought to occur). In this study, evidence was sought for three possible mechanical changes that would support either the sarcomerogenesis or the increased tendon compliance hypotheses: a sustained rightward shift in the fascicle length–tension relationship, reduced fascicle strain amplitude, and reduced starting fascicle length. Methods: Subjects (n = 10) walked backward downhill (5 km/h, 20% incline) on a treadmill for 30 min on two occasions separated by 7 d. Kinematic data and medial gastrocnemius fascicle lengths (ultrasonography) were recorded at 10-min intervals to compare fascicle strains between bouts. Fascicle length–torque curves from supramaximal tibial nerve stimulation were constructed before, 2 h after, and 2 d after each exercise bout. Results: Maximum torque decrement and elevated muscle soreness were present after the first, but not the second, backward downhill walking bout signifying a protective repeated bout effect. There was no sustained rightward shift in the length–torque relationship between exercise bouts, nor decreases in fascicle strain amplitude or shortening of the starting fascicle length. Conclusions: Protection from a repeated bout of eccentric exercise was conferred without changes in muscle fascicle strain behavior, indicating that sarcomerogenesis and increased tendon compliance were unlikely to be responsible. As fascicle strains are relatively small in humans, we suggest that changes to connective tissue structures, such as extracellular matrix remodeling, are better able to explain the repeated bout effect observed here

A new short-faced archosauriform from the Upper Triassic Placerias/Downs’ quarry complex, Arizona, USA, expands the morphological diversity of the Triassic archosauriform radiation

The Placerias/Downs’ Quarry complex in eastern Arizona, USA, is the most diverse Upper Triassic vertebrate locality known. We report a new short-faced archosauriform, Syntomiprosopus sucherorum gen. et sp. nov., represented by four incomplete mandibles, that expands that diversity with a morphology unique among Late Triassic archosauriforms. The most distinctive feature of Syntomiprosopus gen. nov. is its anteroposteriorly short, robust mandible with 3–4 anterior, a larger caniniform, and 1–3 “postcanine” alveoli. The size and shape of the alveoli and the preserved tips of replacement teeth preclude assignment to any taxon known only from teeth. Additional autapomorphies of S. sucherorum gen. et sp. nov. include a large fossa associated with the mandibular fenestra, an interdigitating suture of the surangular with the dentary, fine texture ornamenting the medial surface of the splenial, and a surangular ridge that completes a 90° arc. The external surfaces of the mandibles bear shallow, densely packed, irregular, fine pits and narrow, arcuate grooves. This combination of character states allows an archosauriform assignment; however, an associated and similarly sized braincase indicates that Syntomiprosopus n. gen. may represent previously unsampled disparity in early-diverging crocodylomorphs. The Placerias Quarry is Adamanian (Norian, maximum depositional age ~219 Ma), and this specimen appears to be an early example of shortening of the skull, which occurs later in diverse archosaur lineages, including the Late Cretaceous crocodyliform Simosuchus. This is another case where Triassic archosauriforms occupied morphospace converged upon by other archosaurs later in the Mesozoic and further demonstrates that even well-sampled localities can yield new taxa

Comparison of the Thermal Stability in Equal-Channel-Angular-Pressed and High-Pressure-Torsion-Processed Fe–21Cr–5Al Alloy

Nanostructured Steels Are Expected to Have Enhanced Irradiation Tolerance and Improved Strength. However, They Suffer from Poor Microstructural Stability at Elevated Temperatures. in This Study, Fe–21Cr–5Al–0.026C (Wt%) Kanthal D (KD) Alloy Belonging to a Class of (FeCrAl) Alloys Considered for Accident-Tolerant Fuel Cladding in Light-Water Reactors is Nanostructured using Two Severe Plastic Deformation Techniques of Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT), and their Thermal Stability between 500–700 °C is Studied and Compared. ECAP KD is Found to Be Thermally Stable Up to 500 °C, Whereas HPT KD is Unstable at 500 °C. Microstructural Characterization Reveals that ECAP KD Undergoes Recovery at 550 °C and Recrystallization above 600 °C, While HPT KD Shows Continuous Grain Growth after Annealing above 500 °C. Enhanced Thermal Stability of ECAP KD is from Significant Fraction (\u3e50%) of Low-Angle Grain Boundaries (GBs) (Misorientation Angle 2–15°) Stabilizing the Microstructure Due to their Low Mobility. Small Grain Sizes, a High Fraction (\u3e80%) of High-Angle GBs (Misorientation Angle \u3e15°) and Accordingly a Large Amount of Stored GB Energy, serve as the Driving Force for HPT KD to Undergo Grain Growth Instead of Recrystallization Driven by Excess Stored Strain Energy

Dichlorido(η6-p-cymene)(4-fluoro­aniline-κN)ruthenium(II)

The title compound, [RuCl2(C10H14)(C6H6FN)], a pseudo-octa­hedral d 6 complex, has the expected piano-stool geometry around the Ru(II) atom. The fluoro­aniline ring forms a dihedral angle of 19.3 (2)° with the p-cymene ring. In the crystal, two mol­ecules form an inversion dimer via a pair of N—H⋯Cl hydrogen bonds. Weak inter­molecular C—H⋯Cl inter­actions involving the p-cymene ring consolidate the crystal packing

Imaging ultrafast excited state pathways in transition metal complexes by X-ray transient absorption and scattering using X-ray free electron laser source

This report will describe our recent studies of transition metal complex structural dynamics on the fs and ps time scales using an X-ray free electron laser source, Linac Coherent Light Source (LCLS). Ultrafast XANES spectra at the Ni K-edge of nickel(II) tetramesitylporphyrin (NiTMP) were successfully measured for optically excited state at a timescale from 100 fs to 50 ps, providing insight into its sub-ps electronic and structural relaxation processes. Importantly, a transient reduced state Ni(I) (π, 3d(x2−y2)) electronic state is captured through the interpretation of a short-lived excited state absorption on the low-energy shoulder of the edge, which is aided by the computation of X-ray transitions for postulated excited electronic states. The observed and computed inner shell to valence orbital transition energies demonstrate and quantify the influence of electronic configuration on specific metal orbital energies. A strong influence of the valence orbital occupation on the inner shell orbital energies indicates that one should not use the transition energy from 1s to other orbitals to draw conclusions about the d-orbital energies. For photocatalysis, a transient electronic configuration could influence d-orbital energies up to a few eV and any attempt to steer the reaction pathway should account for this to ensure that external energies can be used optimally in driving desirable processes. NiTMP structural evolution and the influence of the porphyrin macrocycle conformation on relaxation kinetics can be likewise inferred from this study

Ultrafast Excited State Relaxation of a Metalloporphyrin Revealed by Femtosecond X-ray Absorption Spectroscopy

Photoexcited Nickel­(II) tetramesitylporphyrin (NiTMP), like many open-shell metalloporphyrins, relaxes rapidly through multiple electronic states following an initial porphyrin-based excitation, some involving metal centered electronic configuration changes that could be harnessed catalytically before excited state relaxation. While a NiTMP excited state present at 100 ps was previously identified by X-ray transient absorption (XTA) spectroscopy at a synchrotron source as a relaxed (d,d) state, the lowest energy excited state (<i>J. Am. Chem. Soc.</i>, <b>2007</b>, <i>129</i>, 9616 and <i>Chem. Sci.</i>, <b>2010</b>, <i>1</i>, 642), structural dynamics before thermalization were not resolved due to the ∼100 ps duration of the available X-ray probe pulse. Using the femtosecond (fs) X-ray pulses of the Linac Coherent Light Source (LCLS), the Ni center electronic configuration from the initial excited state to the relaxed (d,d) state has been obtained via ultrafast Ni K-edge XANES (X-ray absorption near edge structure) on a time scale from hundreds of femtoseconds to 100 ps. This enabled the identification of a short-lived Ni­(I) species aided by time-dependent density functional theory (TDDFT) methods. Computed electronic and nuclear structure for critical excited electronic states in the relaxation pathway characterize the dependence of the complex’s geometry on the electron occupation of the 3d orbitals. Calculated XANES transitions for these excited states assign a short-lived transient signal to the spectroscopic signature of the Ni­(I) species, resulting from intramolecular charge transfer on a time scale that has eluded previous synchrotron studies. These combined results enable us to examine the excited state structural dynamics of NiTMP prior to thermal relaxation and to capture intermediates of potential photocatalytic significance

An Integrated Approach to Testing Dynamic, Multilevel Theory: Using Computational Models to Connect Theory, Model, and Data

Some of the most influential theories in organizational sciences explicitly describe a dynamic, multilevel process. Yet the inherent complexity of such theories makes them difficult to test. These theories often describe multiple subprocesses that interact reciprocally over time at different levels of analysis and over different time scales. Computational (i.e., mathematical) modeling is increasingly advocated as a method for developing and testing theories of this type. In organizational sciences, however, efforts that have been made to test models empirically are often indirect. We argue that the full potential of computational modeling as a tool for testing dynamic, multilevel theory is yet to be realized. In this article, we demonstrate an approach to testing dynamic, multilevel theory using computational modeling. The approach uses simulations to generate model predictions and Bayesian parameter estimation to fit models to empirical data and facilitate model comparisons. This approach enables a direct integration between theory, model, and data that we believe enables a more rigorous test of theory

Mesoporous carbide-derived carbon with porosity tuned for efficient adsorption of cytokines

Biomaterials, 27(34): pp. 5755-5762.Porous carbons can be used for the purification of various bio-fluids, including the cleansing blood of inflammatory mediators in conditions such as sepsis or auto-immune diseases. Here we show that the control of pore size in carbons is a key factor to achieving efficient removal of cytokines. In particular, the surface area accessible by the protein governs the rate and effectiveness of the adsorption process. We demonstrate that novel mesoporous carbon materials synthesized from ternary MAX-phase carbides can be optimized for efficient adsorption of large inflammatory proteins. The synthesized carbons, having tunable pore size with a large volume of slit-shaped mesopores, outperformed all other materials or methods in terms of efficiency of TNF-α removal and the results are comparable only with highly specific antibody-antigen interactions

Decoding Brain Activity Associated with Literal and Metaphoric Sentence Comprehension Using Distributional Semantic Models

Recent years have seen a growing interest within the natural language processing (NLP)community in evaluating the ability of semantic models to capture human meaning representation in the brain. Existing research has mainly focused on applying semantic models to de-code brain activity patterns associated with the meaning of individual words, and, more recently, this approach has been extended to sentences and larger text fragments. Our work is the first to investigate metaphor process-ing in the brain in this context. We evaluate a range of semantic models (word embeddings, compositional, and visual models) in their ability to decode brain activity associated with reading of both literal and metaphoric sentences. Our results suggest that compositional models and word embeddings are able to capture differences in the processing of literal and metaphoric sentences, providing sup-port for the idea that the literal meaning is not fully accessible during familiar metaphor comprehension