Miracle-dz/UniFAR-FTUs huggingface dataset:
Effects of heat treatment on the thermal and mechanical properties of ramie fabric-reinforced poly(lactic acid) biocomposites

Laminated biocomposites based on ramie fabric and poly(lactic acid) were prepared through hot compression molding followed by direct cooling (without heat treatment) or melt crystallization (with heat treatment). The effects of heat treatment and ramie fabric reinforcement on the thermal and mechanical properties of poly(lactic acid) composites were studied. X-ray diffraction and differential scanning calorimetry measurements confirmed that the heat treatment was able to promote the formation of crystals and enhance the crystallinity of poly(lactic acid), and the addition of ramie fabric also accelerated the crystallization rate of poly(lactic acid). Hence, heat treatment and ramie fabric reinforcement both can improve the thermal stability of poly(lactic acid) biocomposites remarkably. The heat deflection temperature of poly(lactic acid)/24 wt% ramie fabric biocomposite with heat treatment was up to 149.3℃, with a highest increase of 90.7℃. The mechanical properties of the ramie fabric-reinforced poly(lactic acid) biocomposites were also improved after heat treatment.
A Common Neural Substrate for Language Production and Verbal Working Memory

Verbal working memory (VWM), the ability to maintain and manipulate representations of speech sounds over short periods, is held by some influential models to be independent from the systems responsible for language production and comprehension [e.g., Baddeley, A. D. Working memory, thought, and action. New York, NY: Oxford University Press, 2007]. We explore the alternative hypothesis that maintenance in VWM is subserved by temporary activation of the language production system [Acheson, D. J., & MacDonald, M. C. Verbal working memory and language production: Common approaches to the serial ordering of verbal information. Psychological Bulletin, 135, 50–68, 2009b]. Specifically, we hypothesized that for stimuli lacking a semantic representation (e.g., nonwords such as mun), maintenance in VWM can be achieved by cycling information back and forth between the stages of phonological encoding and articulatory planning. First, fMRI was used to identify regions associated with two different stages of language production planning: the posterior superior temporal gyrus (pSTG) for phonological encoding (critical for VWM of nonwords) and the middle temporal gyrus (MTG) for lexical–semantic retrieval (not critical for VWM of nonwords). Next, in the same subjects, these regions were targeted with repetitive transcranial magnetic stimulation (rTMS) during language production and VWM task performance. Results showed that rTMS to the pSTG, but not the MTG, increased error rates on paced reading (a language production task) and on delayed serial recall of nonwords (a test of VWM). Performance on a lexical–semantic retrieval task (picture naming), in contrast, was significantly sensitive to rTMS of the MTG. Because rTMS was guided by language production-related activity, these results provide the first causal evidence that maintenance in VWM directly depends on the long-term representations and processes used in speech production.
150 keV Emission from PKS 2149–306 with BeppoSAX

A BeppoSAX observation of the z = 2.34 quasar PKS 2149-306 produced a strong signal in the high-energy PDS instrument up to a maximum observed energy of nearly 50 keV, 150 keV in the quasar frame. The BeppoSAX spectrum spans almost three decades (0.3-150 keV, quasar frame) and shows an extremely hard (α = 0.4 ± 0.05) X-ray spectrum above 3 keV (comparable to XJB the X-ray background slope), and either a softer (α = 1.0) low-energy component, or an ionized absorber at zero redshift. No evidence is seen of an Fe-K emission line (EW < 167 eV at 6.5 keV quasar frame), a Compton hump (R < 0.3). A bremsstrahlung fit gives kT(rest) = 46 keV, similar to the X-ray background value, and a high-energy cut off power law requires Ecut > 120 keV (quasar frame). The SED of PKS 2149-306 shows two peaks at ~1012±0.5 Hz and ~1021±1.0 Hz (~0.3 mm and ~4 MeV), strongly resembling a low-energy cut off BL Lac object (LBL). The ratio of the two peaks shows an extreme Compton dominance (CD = 1.4 ± 0.4), as in flat-spectrum radio quasars (FSRQs). The presence of an additional "optical/UV big bump" component may provide photons that cool the jet, suppressing the radio emission.
Specific coil design for SENSE: A six‐element cardiac array

In sensitivity encoding (SENSE), the effects of inhomogeneous spatial sensitivity of surface coils are utilized for signal localization in addition to common Fourier encoding using magnetic field gradients. Unlike standard Fourier MRI, SENSE images exhibit an inhomogeneous noise distribution, which crucially depends on the geometrical sensitivity relations of the coils used. Thus, for optimum signal‐to‐noise‐ratio (SNR) and noise homogeneity, specialized coil configurations are called for. In this article we study the implications of SENSE imaging for coil layout by means of simulations and imaging experiments in a phantom and in vivo. New, specific design principles are identified. For SENSE imaging, the elements of a coil array should be smaller than for common phased‐array imaging. Furthermore, adjacent coil elements should not overlap. Based on the findings of initial investigations, a configuration of six coils was designed and built specifically for cardiac applications. The in vivo evaluation of this array showed a considerable SNR increase in SENSE images, as compared with a conventional array. Magn Reson Med 45:495–504, 2001. © 2001 Wiley‐Liss, Inc.
Photoperiodic Effects on Seasonal Physiology, Reproductive Status and Hypothalamic Gene Expression in Young Male F344 Rats

Seasonal or photoperiodically sensitive animals respond to altered day length with changes in physiology (growth, food intake and reproductive status) and behaviour to adapt to predictable yearly changes in the climate. Typically, different species of hamsters, voles and sheep are the most studied animal models of photoperiodism. Although laboratory rats are generally considered nonphotoperiodic, one rat strain, the inbred Fischer 344 (F344) rat, has been shown to be sensitive to the length of daylight exposure by changing its physiological phenotype and reproductive status according to the season. The present study aimed to better understand the nature of the photoperiodic response in the F344 rat. We examined the effects of five different photoperiods on the physiological and neuroendocrine responses. Young male F344 rats were held under light schedules ranging from 8 h of light/day to 16 h of light/day, and then body weight, including fat and lean mass, food intake, testes weights and hypothalamic gene expression were compared. We found that rats held under photoperiods of ≥ 12 h of light/day showed increased growth and food intake relative to rats held under photoperiods of ≤ 10 h of light/day. Magnetic resonance imaging analysis confirmed that these changes were mainly the result of a change in lean body mass. The same pattern was evident for reproductive status, with higher paired testes weight in photoperiods of ≥ 12 h of light/day. Accompanying the changes in physiological status were major changes in hypothalamic thyroid hormone (Dio2 and Dio3), retinoic acid (Crabp1 and Stra6) and Wnt/β‐Catenin signalling genes (sFrp2 and Mfrp). Our data demonstrate that a photoperiod schedule of 12 h of light/day is interpreted as a stimulatory photoperiod by the neuroendocrine system of young male F344 rats.
Opposing effects of negative emotion on amygdalar and hippocampal memory for items and associations

Although negative emotion can strengthen memory of an event it can also result in memory disturbances, as in post-traumatic stress disorder (PTSD). We examined the effects of negative item content on amygdalar and hippocampal function in memory for the items themselves and for the associations between them. During fMRI, we examined encoding and retrieval of paired associates made up of all four combinations of neutral and negative images. At test, participants were cued with an image and, if recognised, had to retrieve the associated (target) image. The presence of negative images increased item memory but reduced associative memory. At encoding, subsequent item recognition correlated with amygdala activity, while subsequent associative memory correlated with hippocampal activity. Hippocampal activity was reduced by the presence of negative images, during encoding and correct associative retrieval. In contrast, amygdala activity increased for correctly retrieved negative images, even when cued by a neutral image. Our findings support a dual representation account, whereby negative emotion up-regulates the amygdala to strengthen item memory but down-regulates the hippocampus to weaken associative representations. These results have implications for the development and treatment of clinical disorders in which diminished associations between emotional stimuli and their context contribute to negative symptoms, as in PTSD.
Inappropriate use of symptom-triggered therapy for alcohol withdrawal in the general hospital.

OBJECTIVE To determine if hospitalized medical and surgical patients were placed inappropriately on symptom-triggered therapy (STT) for alcohol withdrawal syndrome (AWS) and if certain conditions were more likely to be associated with inappropriate STT use or adverse events. PATIENTS AND METHODS We randomly selected 124 (25%) of the 495 Mayo Clinic inpatients who received STT according to the Revised Clinical Institute for Withdrawal Assessment for Alcohol (CIWA-Ar) protocol in 2003 and assessed them for STT appropriateness, defined as having both intact verbal communication and recent alcohol use. Adverse events, including delirium tremens, seizures, or death, were correlated with CIWA-Ar appropriateness. RESULTS Of the 124 randomly selected patients, only 60 (48%) met both inclusion criteria. Of the remaining 64 patients, 9 (14%) were drinkers but could not communicate, and 35 (55%) could communicate but had not been drinking. Twenty (31%) met neither criterion. Univariate analysis identified a significant association between inappropriate initiation and chronic heart failure, postoperative status (POS), liver disease (LD), nonmetastatic cancer, and chemical dependency consultation. On multivariate analysis, only LD (P equals .02) and POS (P equals .01) retained significance, with LD more and POS less likely to predict appropriateness. Seven of 11 patients who experienced adverse events had received STT according to the CIWA-Ar protocol (P equals .05). Univariate analysis identified a significant association between adverse events and a history of alcohol dependence or AWS. Multivariate analysis showed significance only for a history of alcohol dependence (P equals .049). CONCLUSION Fewer than half of the randomly selected patients met both of the inclusion criteria for the CIWA-Ar instrument, leading us to conclude that more stringent evaluation is needed. Particularly postoperatively, alternative explanations for putative AWS should be sought. Health care professionals should more aggressively seek information on recent alcohol use from medical records, family members, and patients themselves.
RF Characteristics of a Fully Ion-Implanted MESFET on a Bulk Semi-Insulating 4H-SiC Substrate

We fabricated a 0.5-μm gate MESFET on a bulk semi-insulating 4H-SiC substrate by using ion implantation for the channel layer and contact region. Nitrogen ions were implanted to obtain a 0.25-μm-thick box-shaped profile with a doping density of 3.0×1017/cm3 for the channel region and to obtain a 0.2-μm-thick box-shaped profile with a doping density of 2.0×1020/cm3 for the contact region. Activation annealing is done in argon ambient at 1300 °C for 30 minutes. A 0.5- μm gate MESFET with 100-μm gate width showed a cut-off frequency of 7.5 GHz and a maximum oscillation frequency of 22.2 GHz. And its saturated output power was 25 dBm (3.16 W/mm), power gain was 6.7 dB and PAE was 15.7%.
The changing Amazon forest

Long-term monitoring of distributed, multiple plots is the key to quantify macroecological patterns and changes. Here we examine the evidence for concerted changes in the structure, dynamics and composition of old-growth Amazonian forests in the late twentieth century. In the 1980s and 1990s, mature forests gained biomass and underwent accelerated growth and dynamics, all consistent with a widespread, long-acting stimulation of growth. Because growth on average exceeded mortality, intact Amazonian forests have been a carbon sink. In the late twentieth century, biomass of trees of more than 10 cm diameter increased by 0.62±0.23 t C ha−1 yr−1 averaged across the basin. This implies a carbon sink in Neotropical old-growth forest of at least 0.49±0.18 Pg C yr−1. If other biomass and necromass components are also increased proportionally, then the old-growth forest sink here has been 0.79±0.29 Pg C yr−1, even before allowing for any gains in soil carbon stocks. This is approximately equal to the carbon emissions to the atmosphere by Amazon deforestation. There is also evidence for recent changes in Amazon biodiversity. In the future, the growth response of remaining old-growth mature Amazon forests will saturate, and these ecosystems may switch from sink to source driven by higher respiration (temperature), higher mortality (as outputs equilibrate to the growth inputs and periodic drought) or compositional change (disturbances). Any switch from carbon sink to source would have profound implications for global climate, biodiversity and human welfare, while the documented acceleration of tree growth and mortality may already be affecting the interactions among millions of species.
Unified analysis of energy harvesting–based MIMO relay wireless systems over Nakagami‐m fading channels

In this paper, we consider two‐hop multi‐input multi‐output relay wireless systems with energy harvesting. In each hop, transmit antenna selection/receive antenna selection, transmit antenna selection/maximum ratio combining, or maximum ratio transmission/receive antenna selection is used. Also, an energy‐constrained relay harvests energy from the source via either a time switching–based relaying protocol or a power splitting–based relaying protocol. We perform unified analysis of the systems over Nakagami‐m fading channels. Specifically, we derive exact closed form expressions for ergodic capacity and throughput (for delay‐tolerant transmission mode) and outage probability and throughput (for delay‐limited transmission). Optimal energy‐harvesting time (in time switching–based relaying protocol–based system) and optimal power‐splitting ratio (in power splitting–based relaying protocol–based system) to achieve maximum throughput at high signal‐to‐noise‐ratio are also determined. Moreover, we derive an exact closed form expression for the bit error rate, which facilitates the evaluation of the system performance. Impacts of various multi‐input multi‐output processing schemes, numbers of equipped antennas, energy‐harvesting mechanisms, and transmission modes on the system performance are also examined and discussed. All theoretical analyses are corroborated by simulations.
Automated Theory Formation in Mathematics

A program called "AM" is described which cairies on simple mathematics research: defining, and studying new concepts under the guidance of a large body of heuiistic rules. The 250 heurKtus communicate via an agenda mechanism, a global priority queue of small bisk', for the program to perform and teasons why each task is plausible (e.g., "Find PENCRAHZTION. of 'prnes', because turued out to be so useful a Concept"). Each concept is an active, structured knowledge module. One bundled very incomplete modules are initially supplied, each one corresponding to an elementary set theoretic concept (e.g., union). This provides a definite but immense space which AM begins to explore. In one boor, AM rediscovers hundreds of common concepts (including singleton sets, natural numbers, arithmetic) and theorems (e.g., unique factorization).
Control of gene conversion and somatic hypermutation by immunoglobulin promoter and enhancer sequences

It is thought that gene conversion (GCV) and somatic hypermutation (SHM) of immunoglobulin (Ig) genes occur in two steps: the generation of uracils in DNA by activation-induced cytidine deaminase, followed by their subsequent repair by various DNA repair pathways to generate sequence-diversified products. It is not known how either of the two steps is targeted specifically to Ig loci. Because of the tight link between transcription and SHM, we have investigated the role of endogenous Ig light chain (IgL) transcriptional control elements in GCV/SHM in the chicken B cell line DT40. Promoter substitution experiments led to identification of a strong RNA polymerase II promoter incapable of supporting efficient GCV/SHM. This surprising finding indicates that high levels of transcription are not sufficient for robust GCV/SHM in Ig loci. Deletion of the IgL enhancer in a context in which high-level transcription was not compromised showed that the enhancer is not necessary for GCV/SHM. Our results indicate that cis-acting elements are important for Ig gene diversification, and we propose that targeting specificity is achieved through the combined action of several Ig locus elements that include the promoter.
Adaptive smoothing lengths in SPH

Context.There is a need to improve the fidelity of SPH simulations of self-gravitating gas dynamics. Aims.We remind users of SPH that, if smoothing lengths are adjusted so as to keep the number of neighbours, ${\cal N}$, in the range ${\cal N}_{{\rm NEIB}}\pm\Delta{\cal N}_{{\rm NEIB}}$, the tolerance, $\Delta{\cal N}_{{\rm NEIB}}$, should be set to zero, as first noted by Nelson & Papaloizou. We point out that this is a very straightforward and computationally inexpensive constraint to implement. Methods.We demonstrate this by simulating acoustic oscillations of a self-gravitating isentropic monatomic gas-sphere (cf. Lucy), using ${\cal N}_{{\rm TOT}}\sim6000$ particles and ${\cal N}_{{\rm NEIB}}=50$. Results.We show that there is a marked reduction in the rates of numerical dissipation and diffusion as $\Delta{\cal N}_{{\rm NEIB}}$ is reduced from 10 to zero. Moreover this reduction incurs a very small computational overhead. Conclusions.We propose that this should become a standard test for codes used in simulating star formation. It is a highly relevant test, because pressure waves generated by the switch from approximate isothermality to approximate adiabaticity play a critical role in the fragmentation of collapsing prestellar cores. Since many SPH simulations in the literature use ${\cal N}_{{\rm NEIB}}=50$ and $\Delta{\cal N}_{{\rm NEIB}}\geq10$, their results must be viewed with caution.
Influence of Rapid Freeze-Thaw Cycling on the Mechanical Properties of Sustainable Strain-Hardening Cement Composite (2SHCC)

This paper provides experimental results to investigate the mechanical properties of sustainable strain-hardening cement composite (2SHCC) for infrastructures after freeze-thaw actions. To improve the sustainability of SHCC materials in this study, high energy-consumptive components—silica sand, cement, and polyvinyl alcohol (PVA) fibers—in the conventional SHCC materials are partially replaced with recycled materials such as recycled sand, fly ash, and polyethylene terephthalate (PET) fibers, respectively. To investigate the mechanical properties of green SHCC that contains recycled materials, the cement, PVA fiber and silica sand were replaced with 10% fly ash, 25% PET fiber, and 10% recycled aggregate based on preliminary experimental results for the development of 2SHCC material, respectively. The dynamic modulus of elasticity and weight for 2SHCC material were measured at every 30 cycles of freeze-thaw. The effects of freeze-thaw cycles on the mechanical properties of sustainable SHCC are evaluated by conducting compressive tests, four-point flexural tests, direct tensile tests and prism splitting tests after 90, 180, and 300 cycles of rapid freeze-thaw. Freeze-thaw testing was conducted according to ASTM C 666 Procedure A. Test results show that after 300 cycles of freezing and thawing actions, the dynamic modulus of elasticity and mass loss of damaged 2SHCC were similar to those of virgin 2SHCC, while the freeze-thaw cycles influence mechanical properties of the 2SHCC material except for compressive behavior.
Insulin Resistance Is Not Associated with an Impaired Mitochondrial Function in Contracting Gastrocnemius Muscle of Goto-Kakizaki Diabetic Rats In Vivo

Insulin resistance, altered lipid metabolism and mitochondrial dysfunction in skeletal muscle would play a major role in type 2 diabetes mellitus (T2DM) development, but the causal relationships between these events remain conflicting. To clarify this issue, gastrocnemius muscle function and energetics were investigated throughout a multidisciplinary approach combining in vivo and in vitro measurements in Goto-Kakizaki (GK) rats, a non-obese T2DM model developing peripheral insulin resistant without abnormal level of plasma non-esterified fatty acids (NEFA). Wistar rats were used as controls. Mechanical performance and energy metabolism were assessed strictly non-invasively using magnetic resonance (MR) imaging and 31-phosphorus MR spectroscopy (31P-MRS). Compared with control group, plasma insulin and glucose were respectively lower and higher in GK rats, but plasma NEFA level was normal. In resting GK muscle, phosphocreatine content was reduced whereas glucose content and intracellular pH were both higher. However, there were not differences between both groups for basal oxidative ATP synthesis rate, citrate synthase activity, and intramyocellular contents for lipids, glycogen, ATP and ADP (an important in vivo mitochondrial regulator). During a standardized fatiguing protocol (6 min of maximal repeated isometric contractions electrically induced at a frequency of 1.7 Hz), mechanical performance and glycolytic ATP production rate were reduced in diabetic animals whereas oxidative ATP production rate, maximal mitochondrial capacity and ATP cost of contraction were not changed. These findings provide in vivo evidence that insulin resistance is not caused by an impairment of mitochondrial function in this diabetic model.
The “Jaws” of the Tau-Microtubule Interaction*

Tau is the major microtubule-associated protein in neuronal axons. It aggregates into “neurofibrillary tangles” during the course of Alzheimer disease. Binding to microtubules and microtubule assembly requires the “repeat domain” in the C-terminal half of Tau, as well as the two regions flanking the repeats. Here we report the NMR characterization of a 198-residue Tau fragment composed of the four tandem repeats and the flanking domains and containing the full microtubule binding and assembly activity of Tau. NMR secondary chemical shifts and dipolar couplings detect the highest propensity for β-structure within the four-repeat region, whereas the flanking domains are largely random coil, with an increased rigidity in the proline-rich region. Chemical shift perturbation experiments identify two motifs in the upstream flanking domain, 225KVAVVRT231 and 243LQTA246, and one downstream of the repeats, 370KIETHKTFREN380, which strongly contribute to the binding to the acidic outside of microtubules, as well as to the binding of other polyanions such as heparin. This is consistent with the “jaws” model of Tau-microtubule interactions and highlights the importance of the regions flanking the repeats for both microtubule binding and pathological Tau aggregation.