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Directionally solidified single crystal superalloy test bars were prepared by the spiral grain selection method. The microstructural evolution and orientation characteristics of the starter block and spiral part were studied, and the influence of the competitive growth of crystals on the microstructural characteristics was analyzed. The results show that the divergent grain groups, with small size and randomly oriented grains, appear at the bottom of the start block due to the chilling effect, which is an important area for competitive growth. As the height of the starter block increases, the primary dendrite spacing increases, and the grain density decreases; furthermore, the proportion of grains with an orientation deflection angle less than 10° gradually increases. The <001> texture gradually becomes stronger as the height of the starter block increases, which indicates that the competitive growth of crystals gradually weakens. At the initial stage of the crystal selection in the spiral part, the obstacle of adjacent grains and spiral passage is the main working mechanism. The grains located at the inner side of the front edge of the spiral passage have the growth advantage. The single crystal screening process is achieved at about two-thirds of the spiral height, and the single crystal with the orientation deviation angle of 6.7° from the casting axis is prepared. [ABSTRACT FROM AUTHOR]

Associated to every symmetrizable generalized intersection matrix A, we define a Lie algebra, called an SIM-Lie algebra. We prove that SIM-Lie algebras keep unchange under braid-equivalences. Two special cases are considered. In the case when A is a symmetrizable generalized Cartan matrix, we show that the corresponding SIM-Lie algebra is just the Kac-Moody Lie algebra. In another case when A is an intersection matrix, we prove that the corresponding SIM-Lie algebra is just the intersection matrix Lie algebra in the sense of Slodowy. [ABSTRACT FROM AUTHOR]

• The nuclear and growth of stray grains lead to the defect of orientation deviation. • Direction of heat flow in the spiral part was inclined toward the spiral direction. • The inclined temperature gradient in spiral passage promoted stray grains' growth. Microstructure evolution and competitive grain growth in the spiral part of a single crystal sample whose crystal orientation deviating from the axial direction was analyzed. The results showed that the appearance of stray grains in the spiral part and the elimination of the originally preferred orientation grains by the competitive growth of stray grains are the reasons for the single-crystal orientation deviation defect. It was indicated that stray grains tend to nucleate at the initial stage of crystal selection in the spiral part. The inclined temperature gradient in the spiral part promoted the development of stray grains, whose growth direction was closer to the direction of the heat flow. Stray grains maintained the competitive growth in the spiral part, and a single crystal with the orientation deviated from the expected direction of 〈0 0 1〉 is formed. [ABSTRACT FROM AUTHOR]

In this paper, for an arbitrary regular biordered setE, by using biorder-isomorphisms between the ?-ideals ofE, we construct a fundamental regular semigroupWE called NH-semigroup ofE, whose idempotent biordered set is isomorphic toE. We prove further thatWE can be used to give a new representation of general regular semigroups in the sense that, for any regular semigroupSwith the idempotent biordered set isomorphic toE, there exists a homomorphism fromStoWE whose kernel is the greatest idempotent-separating congruence onSand the image is a full symmetric subsemigroup ofWE. Moreover, whenEis a biordered set of a semilatticeE0,WE is isomorphic to the Munn-semigroup; and whenEis the biordered set of a bandB,WE is isomorphic to the Hall-semigroupWB. [ABSTRACT FROM AUTHOR]

Flow softening behavior, microstructure evolution and hot working parameters of powder metallurgy Ti–44Al–3Nb-(Mo, V, Y) alloy were systematically studied by isothermal hot compression. Based on the analysis of processing maps and the corresponding microstructure, power dissipation efficiency peak occurred at two domains, which were associated with dynamic recrystallization (DRX) and super-plasticity. Pile-up of high density dislocation and a large number of twins were the primary deformation mechanisms at low temperature and high strain rate. As the temperature increases, fine DRX grains promote the movement and rotation of grain boundary, the softening of β phase and the transformation of β→α/α 2 +γ above 1200 °C improve the deformation capacity of the alloy significantly. Crack-free TiAl sheets were successfully obtained by direct hot rolling process at 1080 °C and 1220 °C. The corresponding microstructure and mechanical properties were analyzed. The sheets rolled at 1080 °C was characterized by near γ (NG)+β 0 microstructure with a streamline along the rolling direction, while duplex (DP)+β 0 microstructure appeared to be the main microstructure at rolling temperature of 1220 °C. The as-rolled sheet exhibits excellent mechanical properties at 800 °C. The sheet rolled at 1080 °C exhibits 320 MPa yield strength and 468 MPa ultimate tensile strength with 142% elongation. The yield strength, ultimate tensile strength, and elongation of the as-rolled sheet are 446 MPa, 586 MPa, and 3.0%, respectively, when rolled at 1220 °C. The excellent ductility of the sample rolled at 1080 °C is attributed to formation of fine DRX grains due to consumption of twins and substructure under tensile stress, which promote grain boundary slip. Lamellar colonies with fine interlamellar spacing and α 2 laths formed at 1220 °C can effectively prevent dislocation motion, resulting in a significant increase in the strength of the alloy. • Hot deformation behavior of PM TiAl alloy was studied by hot compression tests. • Near γ microstructure with homogeneous fine equiaxed grains showed lower flow stress. • Processing window were determined by processing maps and microstructure. • Crack-free TiAl sheets were prepared at 1080 and 1220 °C by hot pack rolling. • High ductility (142%) of the sheet at 800 °C was attributed to the fine DRX grains. [ABSTRACT FROM AUTHOR]

Simple Summary: Honey bees are very important for nature and food production. However, beekeepers' work is continuously challenged by pests, pathogens, pesticides, and other impacts of the environment on their honey bee colonies, and, therefore, they would greatly benefit from up-to-date insights on the health condition of their bees. To disturb those bee colonies as little as possible, it is preferable that this information be collected in an automated way. In this article, we present the B-GOOD project as a case study to monitor the health of honey bee colonies in an automated, standardized way. The use of a similar approach by researchers in their future studies would allow the combination of different datasets on bee health. More data combinations would facilitate the use of machine learning to better and more accurately determine the thresholds for beekeeper interventions, the underlying mechanisms of honey bee colony health, and the prediction of health and colony losses, among other indicators. Honey bee colonies have great societal and economic importance. The main challenge that beekeepers face is keeping bee colonies healthy under ever-changing environmental conditions. In the past two decades, beekeepers that manage colonies of Western honey bees (Apis mellifera) have become increasingly concerned by the presence of parasites and pathogens affecting the bees, the reduction in pollen and nectar availability, and the colonies' exposure to pesticides, among others. Hence, beekeepers need to know the health condition of their colonies and how to keep them alive and thriving, which creates a need for a new holistic data collection method to harmonize the flow of information from various sources that can be linked at the colony level for different health determinants, such as bee colony, environmental, socioeconomic, and genetic statuses. For this purpose, we have developed and implemented the B-GOOD (Giving Beekeeping Guidance by computational-assisted Decision Making) project as a case study to categorize the colony's health condition and find a Health Status Index (HSI). Using a 3-tier setup guided by work plans and standardized protocols, we have collected data from inside the colonies (amount of brood, disease load, honey harvest, etc.) and from their environment (floral resource availability). Most of the project's data was automatically collected by the BEEP Base Sensor System. This continuous stream of data served as the basis to determine and validate an algorithm to calculate the HSI using machine learning. In this article, we share our insights on this holistic methodology and also highlight the importance of using a standardized data language to increase the compatibility between different current and future studies. We argue that the combined management of big data will be an essential building block in the development of targeted guidance for beekeepers and for the future of sustainable beekeeping. [ABSTRACT FROM AUTHOR]

Midbrain dopaminergic (DAergic) regions including ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) are involved in diverse brain functions. Previous studies demonstrated that the VTA/SNc to nucleus accumbens (NAc) pathway is critical in reward and motivation. Moreover, DAergic innervations within the insular cortex (IC) are reported to play important roles in pain regulation. To investigate whether VTA/SNc sends collateral projections to NAc and IC, we injected retrograde tracer Fluoro-Gold (FG) into the NAc and Fluorescent retrograde tracer beads (RetroBeads) into the ipsilateral IC in rats. Then, to detect whether collateral projection neurons participate in neuropathic pain, parts of the rats received the spare nerve injury (SNI) surgery. The immunofluorescence staining results showed that FG, RetroBeads, and FG/RetroBeads double-labeled neurons were distributed in the VTA/SNc bilaterally with an ipsilateral predominance. The proportion of FG/RetroBeads double-labeled neurons to the total number of FG and RetroBeads-labeled neurons was 16.7% and 30.3%, respectively. About 90.3% of FG/RetroBeads double-labeled neurons showed DAergic neuron marker tyrosine hydroxylase (TH)-immunoreactive (IR), whereas, only 7.5% exhibited a subset of GABAergic inhibitory projection neuron marker parvalbumin (PV)-IR. One week after SNI, about 53.1% and 33.6% of FG- and RetroBeads-labeled neurons were FG/Fos- and RetroBeads/Fos-IR neurons, respectively. Finally, about 35.9% of the FG/RetroBeads double-labeled neurons showed Fos-IR. The present study indicates that parts of DAergic and PV-IR GABAergic neurons in the VTA/SNc send collateral projections to both NAc and IC, which are activated under SNI-induced neuropathic pain, and probably contribute to the regulation of nociception. [ABSTRACT FROM AUTHOR]

To elucidate the hot deformation characteristics of TiAl alloys, flow stress prediction, microstructural evolution and deformation mechanisms were investigated in Ti-44Al-5Nb-1Mo-2V-0.2B alloy by isothermal compression tests. A constitutive relationship using the Arrhenius model involving strain compensation and back propagation artificial neural network (BP-ANN) model were developed. A comparison of two models suggested that the BP-ANN model had excellent capabilities and was more accurate in predicting flow stress. Based on the microstructural analysis, bending and elongation of colonies, γ and B2 grains were the main microstructural constituents at low temperature and high strain rate. Dynamic recrystallization (DRX) of γ and dynamic recovery (DRY) of β/B2 were the main deformation mechanisms. With the increase of temperature and decrease of strain rate, phase transformation played an important role. The flake-like γ precipitates in B2 grains, and a coarsening of γ lamellae via α lath dissolution during compression were observed. Additionally, the flow softening process commenced with dislocation pile-up and formation of sub-grain boundaries, followed by grain refinement, twins and nano-lamellar nucleation. Continuous DRX and phase transformation promoted the formability of Ti-44Al-5Nb-1Mo-2V-0.2B alloy. [ABSTRACT FROM AUTHOR]

Abstract Background Müller cell gliosis not only plays an important physiological role by maintaining retinal neuronal homeostasis but is also associated with multiple pathological events in the retina, including optic nerve crush (ONC) injury. Modulating Müller cell gliosis contributes to the creation of a permissive environment for neuronal survival. However, the underlying mechanism of Müller cell gliosis has remained elusive. Objective To investigate the underlying mechanism of Müller cell gliosis after ONC. Methods Rats with ONC injury were transfected with miRNA-21 (miR-21) agomir (overexpressing miR-21) or antagomir (inhibiting miR-21) via intravitreous injection. Immunofluorescence and western blotting were performed to confirm the effects of miR-21 on Müller cell gliosis. The retinal nerve fiber layer (RNFL) thickness was measured using optical coherence tomography and the positive scotopic threshold response (pSTR) was recorded using electroretinogram. Results In the acute phase (14 days) after ONC, compared with the crushed group, inhibiting miR-21 promoted Müller cell gliosis, exhibiting thicker processes and increased GFAP expression. In the chronic phase (35 days), inhibiting miR-21 ameliorated Müller cell gliosis, which exhibited thicker and denser processes and increased GFAP expression. Retinal ganglion cell (RGC) counts in retinas showed that the number of surviving RGCs increased significantly in the antagomir group. The thickness of the RNFL increased significantly, and pSTR showed significant preservation of the amplitudes in the antagomir group. Conclusions Inhibition of miR-21 promotes RGC survival, RNFL thickness and the recovery of RGC function by modulating Müller cell gliosis after ONC. [ABSTRACT FROM AUTHOR]

ABSTRACT Several unbiased genome-wide RNA interference ( RNAi) screens have pointed to mitochondrial metabolism as the major factor for lifespan regulation. However, conflicting data remain to be clarified concerning the mitochondrial free radical theory of aging ( MFRTA). Recently, mTOR (mechanistic target of rapamycin) has been proposed to be the central regulator of aging although how mTOR modulates lifespan is poorly understood. Interestingly, mTOR has been shown to regulate many aspects of mitochondrial function, such as mitochondrial biogenesis, apoptosis, mitophagy and mitochondrial hormesis (mitohormesis) including the retrograde response and mitochondrial unfolded protein response (mito- UPR). Here we discuss the data linking mitochondrial metabolism to mTOR regulation of lifespan, suggesting that hormetic effects may be key to explaining some controversial results regarding the MFRTA. We also discuss the possibility that dysfunction of mitochondrial adaptive responses rather than free radicals per se contributes to the aging process. [ABSTRACT FROM AUTHOR]

ABSTRACT Background/Objectives: Free radicals and reactive oxygen species (ROS), which are generated by UV irradiation, may induce an irreversible growth arrest similar to senescence. Tiron, 4,5-dihydroxy-1,3-benzene disulfonic acid, is a widely used antioxidant to rescue ROS-evoked cell death. The aim of the article was to explore the effects of tiron on skin photoaging and associated mechanisms. Methods: The effects of tiron on cell proliferation were determined using 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide. Senescent cells were determined by morphology and senescence-associated β-galactosidase activity analysis. Intracellular hydrogen peroxide, superoxide anion and glutathione concentration were analysed by a fluorescent probe. The concomitant changes of protein expression were analysed with Western blot. Results: Human dermal fibroblasts were induced to premature senescence by sub-cytotoxic doses of irradiated UVB. Strong senescence-associated β-galactosidase activity and increased intracellular superoxide anion were observed in human dermal fibroblasts irradiated by UVB. Tiron blocks UVB-induced glutathione depletion and increase of superoxide anion and protects against UVB-induced senescence-like characteristics in human dermal fibroblasts. Compared with normal fibroblasts, UVB-irradiated human dermal fibroblasts showed a higher ratio of active (hypophosphorylated) to inactive (phosphorylated) forms of Rb and p38, upregulation of p53 or p16 and c-Myc and insulin-like growth factor 1 (IGF-1) downregulation. After treatment with tiron, p53, p16 c-Myc and IGF-1 as well as phosphorylation Rb and p38 could partially recover. Conclusion: These results indicate that tiron protects against UVB-induced senescence-like characteristics in human dermal fibroblasts via the inhibition of production of superoxide anion and glutathione depletion, and modulation of related senescence proteins. [ABSTRACT FROM AUTHOR]

Diffuse axonal injury (DAI) is the predominant effect of severe traumatic brain injury and significantly contributes to cognitive deficits. The mechanisms that underlie these cognitive deficits are often associated with complex molecular alterations. α7nAChR, one of the abundant and widespread nicotinic acetylcholine receptors (nAChRs) in the brain, plays important physiological functions in the central nervous system. However, the relationship between temporospatial alterations in the α7nAChR and DAI-related learning and memory dysfunction are not completely understood. Our study detected temporospatial alterations of α7nAChR in vulnerable areas (hippocampus, internal capsule, corpus callosum and brain stem) of DAI rats and evaluated the development and progression of learning and memory dysfunction via the Morris water maze (MWM). We determined that α7nAChR expression in vulnerable areas was mainly reduced at the recovery of DAI in rats. Moreover, the escape latency of the injured group increased significantly and the percentages of the distance travelled and time spent in the target quadrant were significantly decreased after DAI. Furthermore, α7nAChR expression in the vulnerable area was significantly positively correlated with MWM performance after DAI according to regression analysis. In addition, we determined that a selective α7nAChR agonist significantly improved learning and memory dysfunction. Rats in the α7nAChR agonist group showed better learning and memory performance than those in the antagonist group. These results demonstrate that microstructural injury-induced alterations of α7nAChR in the vulnerable area are significantly correlated with learning and memory dysfunctions after DAI and that augmentation of the α7nAChR level by its agonist contributes to the improvement of learning and memory function. [ABSTRACT FROM AUTHOR]

Background: Oridonin, a tetracycline diterpenoid compound, has the potential antitumor activities. Here, we evaluate the antitumor activity and action mechanisms of oridonin in colorectal cancer.Methods: Effects of oridonin on cell proliferation were determined by using a CCK-8 Kit. Cell cycle distribution was determined by flow cytometry. Apoptosis was examined by analyzing subdiploid population and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Senescent cells were determined by senescence-associated β-galactosidase activity analysis. Semi-quantitative RT-PCR was used to examine the changes of mRNA of p16, p21, p27 and c-myc. The concomitant changes of protein expression were analyzed with Western blot. Expression of AcH3 and AcH4 were examined by immunofluorescence staining and Western blots. Effects of oridonin on colony formation of SW1116 were examined by Soft Agar assay. The in vivo efficacy of oridonin was detected using a xenograft colorectal cancer model in nude mice.Results: Oridonin induced potent growth inhibition, cell cycle arrest, apoptosis, senescence and colony-forming inhibition in three colorectal cancer cell lines in a dose-dependent manner in vitro. Daily i.p. injection of oridonin (6.25, 12.5 or 25 mg/kg) for 28 days significantly inhibited the growth of SW1116 s.c. xenografts in BABL/C nude mice. With western blot and reverse transcription-PCR, we further showed that the antitumor activities of oridonin correlated with induction of histone (H3 and H4) hyperacetylation, activation of p21, p27 and p16, and suppression of c-myc expression.Conclusion: Oridonin possesses potent in vitro and in vivo anti-colorectal cancer activities that correlated with induction of histone hyperacetylation and regulation of pathways critical for maintaining growth inhibition and cell cycle arrest. Therefore, oridonin may represent a novel therapeutic option in colorectal cancer treatment. [ABSTRACT FROM AUTHOR]