•We develop a heater to study boiling on rough surfaces using infrared thermometry.•A stochastic heat partitioning model captures the boiling curve.•The boiling crisis is a critical transition in the ...near-wall bubble coalescence process.•The boiling crisis is captured by a continuum percolation model.
We design and build a special heater to enable infrared investigations of boiling heat transfer on surfaces featuring the typical roughness and scratch pattern of commercial-grade heat transfer surfaces (in this case a zirconium alloy typically used as fuel cladding material in nuclear reactors). We use high-speed infrared thermometry to investigate surface effects on the boiling process for both the rough infrared heater and a reference more conventional, nano-smooth infrared heater. Compared to the nano-smooth surface, the rough surface has larger nucleation sites, which require a lower nucleation temperature. The rough surface has a much smaller bubble departure volume. However, it has a much higher nucleation site density, and, overall, a higher heat transfer coefficient. We capture this behavior with a stochastic heat flux partitioning model. Notably, while the two surfaces have very different boiling dynamics, the boiling crisis has a common “signature”. For both surfaces, the probability density functions of bubble footprint areas follow a power law with a negative exponent smaller than 3, also known as a scale-free distribution. We predict these observations and the onset of the boiling crisis using a continuum percolation model. These results corroborate the hypothesis of the boiling crisis as a percolative critical phase transition of the bubble interaction process.
Insufficient sleep increasingly characterizes modern society, contributing to a host of serious medical problems. Loss of sleep is associated with metabolic diseases such as obesity and diabetes, ...cardiovascular disorders, and neurological and cognitive impairments. Shifts in gut microbiome composition have also been associated with the same pathologies; therefore, we hypothesized that sleep restriction may perturb the gut microbiome to contribute to a disease state. In this study, we examined the fecal microbiome by using a cross-species approach in both rat and human studies of sleep restriction. We used DNA from hypervariable regions (V1-V2) of 16S bacteria rRNA to define operational taxonomic units (OTUs) of the microbiome. Although the OTU richness of the microbiome is decreased by sleep restriction in rats, major microbial populations are not altered. Only a single OTU, TM7-3a, was found to increase with sleep restriction of rats. In the human microbiome, we find no overt changes in the richness or composition induced by sleep restriction. Together, these results suggest that the microbiome is largely resistant to changes during sleep restriction.
Somatic embryogenesis requires auxin and establishment of the shoot apical meristem (SAM). WUSCHEL (WUS) is critical for stem cell fate determination in the SAM of higher plants. However, regulation ...of WUS expression by auxin during somatic embryogenesis is poorly understood. Here, we show that expression of several regulatory genes important in zygotic embryogenesis were up-regulated during somatic embryogenesis of Arabidopsis. Interestingly, WUS expression was induced within the embryonic callus at a time when somatic embryos could not be identified morphologically or molecularly. CorrectWUS expression, regulated by a defined critical level of exogenous auxin, is essential for somatic embryo induction. Furthermore, it was found that auxin gradients were established in specific regions that could then give rise to somatic embryos. The establishment of auxin gradients was correlated with the induced WUS expression. Moreover, the auxin gradients appear to activate PIN1 polar localization within the embryonic callus. Polarized PIN1 is probably responsible for the observed polar auxin transport and auxin accumulation in the SAM and somatic embryo. Suppression of WUS and PIN1 indicated that both genes are necessary for embryo induction through their regulation of downstream gene expression. Our results reveal that establishment of auxin gradients and PIN1-mediated polar auxin transport are essential for WUS induction and somatic embryogenesis. This study sheds new light on how auxin regulates stem cell formation during somatic embryogenesis.
Agnathan fish hold a key position in vertebrate evolution, especially regarding the origin of the head and neural-crest-derived tissue. In contrast to amphioxus, lampreys and other vertebrates ...possess a complex brain and placodes that contribute to well-developed eyes, as well as auditory and olfactory systems. These sensory sytems were arguably a trigger to subsequent vertebrate diversifications. However, although they are known from skeletal impressions in younger Palaeozoic agnathans, information about the earliest records of these systems has been largely wanting. Here we report numerous specimens of the Lower Cambrian vertebrate Haikouichthys ercaicunensis, until now only known from the holotype. Haikouichthys shows significant differences from other fossil agnathans: key features include a small lobate extension to the head, with eyes and possible nasal sacs, as well as what may be otic capsules. A notochord with separate vertebral elements is also identifiable. Phylogenetic analysis indicates that this fish lies within the stem-group craniates. Although Haikouichthys somewhat resembles the ammocoete larva of modern lampreys, this is because of shared general craniate characters; adult lampreys and hagfishes (the cyclostomes if monophyletic) are probably derived in many respects.
Boron geochemistry can track fluid–rock interaction during metamorphic evolution and provides important insights into mass transfer processes in subduction zones. This study presents boron ...concentration and isotopic data for white mica (phengite and paragonite) and tourmaline in an ultra-high pressure (UHP) metapelitic schist from the western Tianshan (Xinjiang Province, China). The pelitic schist experienced dehydration during heating related to the onset of exhumation, which is recorded by phengite and tourmaline formed during this stage. Boron isotope ratios in phengite decreased from – 8.5 to – 16.0 ‰ (relative to NIST SRM 951) with increasing temperature from 525 to 575 °C. This is recorded in a correlated decrease of
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B/
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B ratios, B content and Si content of phengite. Thus, the B isotopes of released fluids during decompression–heating evolved from 0 to – 6.9 ‰, consistent with a preferential loss of isotopically heavy B during dehydration. The formation of BSE-dark zones in tourmaline with relatively light δ
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B values (– 9 to – 6‰) and high Mg
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(0.65–0.68) could be related with fluids released during this stage. In a second stage, paragonite formed in a rehydration process during advanced exhumation. During interaction with external fluids, boron concentrations and isotopic values in paragonite increased: B concentration range from 72 to 232 μg/g, and δ
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B increased from – 15.6 to – 2.5 ‰. Fluid-fractionation modeling demonstrates that the external fluid (B) = 340 ± 20 μg/g; δ
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B = + 8 ± 2 ‰ may have been derived from high-δ
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B serpentinites that occur in the study area (δ
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B between – 1 and + 8 ‰). In response to hydration, tourmaline likely developed BSE-light zones with heavier δ
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B values (− 4 to − 2‰) and lower Mg
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(0.62–0.64). Boron geochemistry of white micas and tourmaline improve our understanding of mass transfer during metamorphic processes in subduction zones; it allows us to identify the influence of both closed-system recrystallization events and the effect and likely source of externally derived fluids.
Survivin is ubiquitously expressed in patients with head neck squamous cell carcinoma (HNSCC) and is associated with poor survival and chemotherapy resistance. Sepantronium bromide (YM155) is a ...selective survivin suppressant that exhibits potent antitumor activities by inducing apoptosis and autophagy in various types of cancer. However, the curative effects and underlying mechanisms of YM155 in HNSCC remain unclear. This study showed that survivin overexpression positively correlated with p-S6, p-Rb and LAMP2 but negatively correlated with the autophagic marker LC3 in human HNSCC tissues. In vitro studies revealed that YM155 triggered apoptosis of HNSCC cells in mitochondria and death receptor-dependent manner. The treatment also significantly enhanced autophagy by upregulating Beclin1, which led to cell death. YM155 not only downregulated the expression of survivin but also remarkably suppressed the activation of the mTOR signaling pathway in vitro and in vivo. YM155 displayed potent antitumor activities in both CAL27 xenograft and transgenic HNSCC mice models by delaying tumor onset and suppressing tumor growth. Furthermore, YM155 combined with docetaxel promoted tumor regression better than either treatment alone without causing considerable body weight loss in the HNSCC xenograft models. Overall, targeting survivin by YM155 can benefit HNSCC therapy by increasing apoptotic and autophagic cell death, and suppressing prosurvival pathways.
The effects of dietary supplementation of essential oil on growth performance, carcass yield, meat quality, serum antioxidant capacity, and intestinal tight junctions of broilers with or without ...Eimeria challenge were investigated. A total of 576 one-day-old male broilers were randomly separated into 8 treatments (6 replication floor-pens per treatment, 12 broilers per pen) in a 4 × 2 factorial design. The 4 diets consisted of 1) a corn and soybean meal basal diet, 2) an anticoccidial diet (60 g nicarbazin and 60 g narasin per ton of feed), 3) an oregano oil diet (500 ppm oregano oil), and 4) a clove oil diet (500 ppm clove oil). On d 10, half chicks were challenged with 1 × 104 sporulated oocysts of E. tenella, E. acervulina, and E. maxima per chick, whereas the others were inoculated with an equal amount of dilution (0.5 mL). The Eimeria challenge induced a higher fecal oocyst output on d 18, a lower duodenum Occludin expression level on d 28, a lower serum catalase level, and a higher cook loss and protein loss in thigh muscle on d 42. The anticoccidial diet lowered fecal Eimeria output and increased d 1 to 42 BW gain as compared to the control diet. The clove oil treatment enhanced duodenum ZO-1 expression level in nonchallenged birds, increased BW gain from d 1 to 14 and breast yield on d 42. The oregano oil treatment enhanced ZO-1 expression of challenged birds, reduced feed intake from 15 to 28 d, and helped broilers gain more tender meat. For those Eimeria-challenged broilers, both clove and oregano oil treatments recovered drip loss in breast muscle. Our results suggested that Eimeria challenge in broiler early age could interrupt later serum antioxidant capacity and damage meat quality. The dietary supplementation of clove or oregano essential oils could improve broiler growth performance and partially relieve the coccidial damage in gut integrity and meat quality.
Specialized junctional sites that connect the plasma membrane (PM) and endoplasmic reticulum (ER) play critical roles in controlling lipid metabolism and Ca(2+) signalling. Store-operated Ca(2+) ...entry mediated by dynamic STIM1-ORAI1 coupling represents a classical molecular event occurring at ER-PM junctions, but the protein composition and how previously unrecognized protein regulators facilitate this process remain ill-defined. Using a combination of spatially restricted biotin labelling in situ coupled with mass spectrometry and a secondary screen based on bimolecular fluorescence complementation, we mapped the proteome of intact ER-PM junctions in living cells without disrupting their architectural integrity. Our approaches led to the discovery of an ER-resident multi-transmembrane protein that we call STIMATE (STIM-activating enhancer, encoded by TMEM110) as a positive regulator of Ca(2+) influx in vertebrates. STIMATE physically interacts with STIM1 to promote STIM1 conformational switch. Genetic depletion of STIMATE substantially reduces STIM1 puncta formation at ER-PM junctions and suppresses the Ca(2+)-NFAT signalling. Our findings enable further genetic studies to elucidate the function of STIMATE in normal physiology and disease, and set the stage to uncover more uncharted functions of hitherto underexplored ER-PM junctions.
Chronic obstructive pulmonary disease (COPD) is one of the main contributors to the global burden of disease. The aim of this systematic review was to quantify the disease burden of COPD in China and ...to determine the risk factors of the disease. The number of studies included in the review was 47 with an average quality assessment score of 7.70 out of 10. Reported COPD prevalence varied between 1.20% and 8.87% in different provinces/cities across China. The prevalence rate of COPD was higher among men (7.76%) than women (4.07%). The disease was more prevalent in rural areas (7.62%) than in urban areas (6.09%). The diagnostic rate of COPD patients in China varied from 23.61% to 30.00%. The percentage of COPD patients receiving outpatient treatment was around 50%, while the admission rate ranged between 8.78% and 35.60%. Tobacco exposure and biomass fuel/solid fuel usage were documented as two important risk factors of COPD. COPD ranked among the top three leading causes of death in China. The direct medical cost of COPD ranged from 72 to 3,565 USD per capita per year, accounting for 33.33% to 118.09% of local average annual income. The most commonly used scales for the assessment of quality of life (QoL) included Saint George Respiratory Questionnaire, Airways Questionnaire 20, SF-36, and their revised versions. The status of QoL was worse among COPD patients than in non-COPD patients, and COPD patients were at higher risks of depression. The COPD burden in China was high in terms of economic burden and QoL. In view of the high smoking rate and considerable concerns related to air pollution and smog in China, countermeasures need to be taken to improve disease prevention and management to reduce disease burdens raised by COPD.
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