Plasma carburizing of 12CrNi2 alloy steel fabricated by laser melting deposition was carried out in a propane-containing atmosphere at temperature of 930 °C with and without hollow cathode discharge ...(HCD). The generation of the HCD in the carburizing process was achieved by adding an auxiliary cathode opposite the alloy steel sample. The carburized samples were characterized by analysis of microstructure, microhardness and wear performance. The assistance of HCD increased the carbon concentration in the carburized layer and the case depth without changing the carburizing atmosphere and discharge voltage, indicating the improvement of carburizing kinetics. This leads to an increased volume fraction of acicular martensite and an increased the microhardness of the carburized layer as well as the improvement of the wear resistance of alloy steel.
•Laser melting deposition (LMD) technology fabricated 12CrNi2 alloy steel.•Plasma carburizing effectively hardened the LMD fabricated alloy steel.•Hollow cathode discharge increased the carburizing kinetics.
Mechanosensitive ion channels have been suggested to be expressed in dental primary afferent (DPA) neurons to transduce the movement of dentinal fluid since the proposal of hydrodynamic theory. ...Piezo2, a mechanosensitive, rapidly inactivating (RI) ion channel, has been recently identified in dorsal root ganglion (DRG) neurons to mediate tactile transduction. Here, we examined the expression of Piezo2 in DPA neurons by in situ hybridization, single-cell reverse transcriptase polymerase chain reaction, and whole-cell patch-clamp recordings. DPA neurons with Piezo2 messenger RNA (mRNA) or Piezo2-like currents were further characterized based on their neurochemical and electrophysiological properties. Piezo2 mRNA was found mostly in medium- to large-sized DPA neurons, with the majority of these neurons also positive for Nav1.8, CGRP, and NF200, whereas only a minor population was positive for IB4 and peripherin. Whole-cell patch-clamp recordings revealed Piezo2-like, RI currents evoked by mechanical stimulation in a subpopulation of DPA neurons. RI currents were pharmacologically blocked by ruthenium red, a compound known to block Piezo2, and were also reduced by small interfering RNA-mediated Piezo2 knockdown. Piezo2-like currents were observed almost exclusively in IB4-negative DPA neurons, with the current amplitude larger in capsaicin-insensitive DPA neurons than the capsaicin-sensitive population. Our findings show that subpopulation of DPA neurons is indeed mechanically sensitive. Within this subpopulation of mechanosensitive DPA neurons, we have identified the Piezo2 ion channel as a potential transducer for mechanical stimuli, contributing to RI inward currents. Piezo2-positive DPA neurons were characterized as medium- to large-sized neurons with myelinated A-fibers, containing nociceptive peptidergic neurotransmitters.
Estimation of horizontal stress magnitudes from borehole breakouts has been an attractive topic in the petroleum and mining industries, although there are critical research gaps that remain unfilled. ...In this paper, numerical simulation is conducted on Gosford sandstone to investigate the borehole breakout and its associated borehole size effect, including temperature influence. The discrete element method (DEM) model shows that the borehole breakout angular span is constant after the initial formation, whereas its depth propagates along the minimum horizontal stress direction. This indicates that the breakout angular span is a reliable parameter for horizontal stress estimation. The borehole size effect simulations illustrated the importance of borehole size on breakout geometries in which smaller borehole size leads to higher breakout initiation stress as well as the stress re-distribution from borehole wall outwards through micro-cracking. This implies that the stress may be averaged over a distance around the borehole and breakout initiation occurs at the borehole wall rather than some distance into the rock. In addition, the numerical simulation incorporated the thermal effect which is widely encountered in deep geothermal wells. Based on the results, the higher temperature led to lower breakout initiation stress with same borehole size, and more proportion of shear cracks was generated under higher temperature. This indicates that the temperature might contribute to the micro-fracturing mode and hence influences the horizontal stress estimation results from borehole breakout geometries. Numerical simulation showed that breakout shape and dimensions changed considerably under high stress and high temperature conditions, suggesting that the temperature may need to be considered for breakout stress analysis in deep locations.
The ubiquitin proteasome system (UPS) plays a crucial role in biological processes integral to the development of the cardiovascular system and cardiovascular diseases. The UPS prototypically ...recognizes specific protein substrates and places polyubiquitin chains on them for subsequent destruction by the proteasome. This system is in place to degrade not only misfolded and damaged proteins, but is essential also in regulating a host of cell signaling pathways involved in proliferation, adaptation to stress, regulation of cell size, and cell death. During the development of the cardiovascular system, the UPS regulates cell signaling by modifying transcription factors, receptors, and structural proteins. Later, in the event of cardiovascular diseases as diverse as atherosclerosis, cardiac hypertrophy, and ischemia/reperfusion injury, ubiquitin ligases and the proteasome are implicated in protecting and exacerbating clinical outcomes. However, when misfolded and damaged proteins are ubiquitinated by the UPS, their destruction by the proteasome is not always possible because of their aggregated confirmations. Recent studies have discovered how these ubiquitinated misfolded proteins can be destroyed by alternative “specific” mechanisms. The cytosolic receptors p62, NBR, and histone deacetylase 6 recognize aggregated ubiquitinated proteins and target them for autophagy in the process of “selective autophagy.” Even the ubiquitination of multiple proteins within whole organelles that drive the more general macro-autophagy may be due, in part, to similar ubiquitin-driven mechanisms. In summary, the crosstalk between the UPS and autophagy highlight the pivotal and diverse roles the UPS plays in maintaining protein quality control and regulating cardiovascular development and disease.
Rationale: Adrenal histoplasmosis can present as bilateral adrenal enlargement with constitutional symptoms and/or adrenal insufficiency. Often these patients are initially investigated as secondary ...adrenal metastases before eventually their diagnosis established by histopathological examination of the adrenal tissues. Patients concerns: We report 4 cases of patients aged 55-78 who presented with hypocortisolism and bilateral adrenal masses. Diagnoses: Bilateral adrenal histoplasmosis. Interventions: Three patients received antifungal treatment for at least one year while 1 patient passed away before the initiation of antifungal treatment. Outcomes: Two patients’ adrenal function recovered not requiring any steroid replacement, while 1 patient still requires long-term steroid replacement. Lessons: Adrenal histoplasmosis should be excluded in patients from endemic areas presenting with bilateral adrenal masses and adrenal insufficiency. Usually patients have an exposure to bird droppings, bat guano or soil contaminated with histoplasmosis fungi. Histopathological examination of biopsied adrenal tissues is still the gold standard investigation as serology and molecular diagnostic methods are still not widely available in most centers in Malaysia.
A large number of female goats are needed for the dairy goat industry; therefore, the development of a method to ensure the birth of more females than males in a single pregnancy will lead to ...economic benefits. Increasing the number of X-sperm would be an effective way to increase the proportion of female offspring. In this study, goat semen was incubated at pH 7.4 in alkaline diluent combined with resiquimod (R848) and the number of X-sperm was enriched by the swim-up method. The percentage of X-sperm was determined using the double TaqMan qPCR method. Sperm total motility, progressive motility, average path velocity, straight-line velocity, and curvilinear velocity were measured using a computer-aided sperm analysis system, and the functional parameters of the sperm plasma membrane, the acrosome, mitochondrial activity, ATP content, and reactive oxygen species levels were also measured. Lastly, the ratio of female embryos was determined by in vitro fertilization, and the number of female kids and the pregnancy rate of does was assessed by artificial insemination. The results showed that dilution of semen in an alkaline buffer containing R848 could enrich the number of X-sperm to 85.57% ± 3.27%. The progressive motility, average path velocity, straight-line velocity, curvilinear velocity, mitochondrial activity, and ATP level of the collected X-sperm-enriched semen were significantly reduced, but its total motility, plasma membrane, and acrosome were not affected. The in vitro fertilization experiments showed that the rate of female embryo production using X-sperm-rich seminal fluid could reach 83.25% (174/209), which was significantly higher than the proportion of female embryos in the control group, 47.71% ± 1.80% (104/218). As determined by artificial insemination, the number of female kids in the test group increased by 62.79% (243/387), which was significantly higher than that in the control group (47.65%, 193/405). There was no significant difference in pregnancy rate between the test group and the control group (71.71% vs. 78.48%). Therefore, this study demonstrated that use of a pH 7.4 diluent containing R848 is a simple and effective method of X-sperm enrichment for dairy goat production. Its application would allow does to produce more female offspring for herd expansion and milk production.
The ground state property of a Au-induced atomic wire array on a stepped Si(553) surface with interesting 1D metallic bands was investigated. Electron diffraction and scanning tunneling microscopy ...reveal an intriguing coexistence of triple- and double-period lattice distortions at low temperature. Angle-resolved photoemission observes both the nearly 1/3- and 1/2-filled bands to gradually open energy gaps upon cooling. We explain these unusual findings as due to the occurrence of Peierls distortions of triple and double periods on the two different atomic-scale chain elements, respectively, within a single unit wire. The two Peierls distortions are suggested to have different transition temperatures and little lateral correlation between each other.
Prediction of human physical traits and demographic information from genomic data challenges privacy and data deidentification in personalized medicine. To explore the current capabilities of ...phenotype-based genomic identification, we applied whole-genome sequencing, detailed phenotyping, and statistical modeling to predict biometric traits in a cohort of 1,061 participants of diverse ancestry. Individually, for a large fraction of the traits, their predictive accuracy beyond ancestry and demographic information is limited. However, we have developed a maximum entropy algorithm that integrates multiple predictions to determine which genomic samples and phenotype measurements originate from the same person. Using this algorithm, we have reidentified an average of >8 of 10 held-out individuals in an ethnically mixed cohort and an average of 5 of either 10 African Americans or 10 Europeans. This work challenges current conceptions of personal privacy and may have far-reaching ethical and legal implications.
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