59 research outputs found

    License BSD_3_clause + file LICENSE

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    R topics documented: RQDA-package....................................... 2 casesCodedBy........................................ 3 codingBySearch....................................... 4 crossCodes......................................... 6 Deletion........................................... 7 exportCodedFile...................................... 8 exportCodings........................................ 9 filesByCodes........................................ 10 filesCodedBy........................................ 10 getAttr............................................ 11 getCases........................................... 13 getCodingsByOne...................................... 14 getCodingTable....................................... 15 getFileIdSets........................................ 1

    Effect of solvation shell structure on thermopower of liquid redox pairs

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    Recent advancements in thermogalvanic batteries offer a promising route to efficient harvesting of low-grade heat with temperatures below 100 {\deg}C. The thermogalvanic temperature coefficient {\alpha}, usually referred to as effective thermopower, is the key parameter determining the power density and efficiency of thermogalvanic batteries. However, the current understanding of improving {\alpha} of redox pairs remains at the phenomenological level without microscopic insights, and the development of electrolytes with high {\alpha} largely relies on experimental trial and error. This work applies the free energy perturbation method based on molecular dynamics simulations to predict the {\alpha} of the {Fe^{3+}/Fe^{2+}} redox pair in aqueous and acetone solutions. We showed that {\alpha} of the {Fe^{3+}/Fe^{2+}} redox pair can be increased from 1.5{\pm}0.3 mV/K to 4.1{\pm}0.4 mV/K with the increased acetone to water fraction. The predicted {\alpha} of {Fe^{3+}/Fe^{2+}} both in pure water and acetone show excellent agreement with experimental values. By monitoring the fluctuation of dipole orientations in the first solvation shell, we discovered a significant change in the variance of solvent dipole orientation between Fe^{3+} and Fe^{2+}, which can be a microscopic indicator for large magnitudes of {\alpha}. The effect of acetone weight fraction in the mixed acetone-water solvent on the {\alpha} of {Fe^{3+}/Fe^{2+}} is also studied. Acetone molecules are found to intercalate into the first solvation shell of the {Fe^{2+}} ion at high acetone fractions, while this phenomenon is not observed in the solvation shell of the Fe^{3+} ion. Such solvation shell structure change of {Fe^{2+}} ions contributes to the enhanced {\alpha} at high acetone fractions. Our discovery provides atomistic insights into how solvation shell order can be leveraged to develop electrolytes with high thermopower

    Past distribution of epiphyllous liverworts in China: The usability of historical data

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    Epiphyllous liverworts form a special group of bryophytes that primarily grow on the leaves of understory vascular plants in tropical and subtropical evergreen broadleaf forests. Being sensitive to moisture and temperature changes, epiphyllous liverworts are often considered to be good indicators of climate change and forest degradation. However, they are a poorly collected and taxonomically complicated group, with an only partly identified distribution pattern. In this study, we built four models based on 24 environmental variables at four different spatial resolutions (i.e., 1 km, 5 km, 10 km, and 15 km) to predict the past distribution of epiphyllous liverworts in China, using Maxent model and 63 historical location records (i.e., presence‐only data). Both area under the curve of the receiver operating characteristic (AUC) and true skill statistic (TSS) methods are used to assess the model performance. Results showed that the model with the predictors at a 15‐km resolution achieved the highest predictive accuracy (AUC=0.946; TSS=0.880), although there was no statistically significant difference between the four models (p > 0.05). The most significant environmental variables included aridity, annual precipitation, precipitation of wettest month, precipitation of wettest quarter, and precipitation of warmest quarter, annual mean NDVI, and minimum NDVI. The predicted suitable areas for epiphyllous liverworts were mainly located in the south of Yangtze River and seldom exceed 35°N, which were consistent with the museum and herbarium records, as well as the historical records in scientific literatures. Our study further demonstrated the value of historical data to ecological and evolutionary studies

    Biphilic Nanoporous Surfaces Enabled Exceptional Drag Reduction and Capillary Evaporation Enhancement

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    Simultaneously achieving drag reduction and capillary evaporation enhancement is highly desired but challenging because of the trade-off between two distinct hydrophobic and hydrophilic wettabilities. Here, we report a strategy to synthesize nanoscale biphilic surfaces to endow exceptional drag reduction through creating a unique slip boundary condition and fast capillary wetting by inducing nanoscopic hydrophilic areas. The biphilic nanoporous surfaces are synthesized by decorating hydrophilic functional groups on hydrophobic pristine multiwalled carbon nanotubes. We demonstrate that the carbon nanotube-enabled biphilic nanoporous surfaces lead to a 63.1% reduction of the friction coefficient, a 61.7% wetting speed improvement, and up to 158.6% enhancement of capillary evaporation heat transfer coefficient. A peak evaporation heat transfer coefficient of 21.2W/(cm2 K) is achieved on the biphilic surfaces in a vertical direction

    HT2008-56339 CURVATURE EFFECT ON THE THERMAL CONDUCTIVITY OF NANOWIRES

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    ABSTRACT Directional preference of the ballistic phonon transport plays an important role in the effective thermal conductivity of nanostructures. Curved nanowires can have very different thermal conductivities from straight ones. In this work, a Monte-Carlo simulator is developed and used to investigate the curvature effect on the phonon transport in silicon nanowires. The results show that the curvature of geometry does not alter the phonon transport efficiency in large wires but decreases the effective thermal conductivity in their nano-sized counterparts

    Iron Metabolism Regulates p53 Signaling through Direct Heme-p53 Interaction and Modulation of p53 Localization, Stability, and Function

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    Iron excess is closely associated with tumorigenesis in multiple types of human cancers, with underlying mechanisms yet unclear. Recently, iron deprivation has emerged as a major strategy for chemotherapy, but it exerts tumor suppression only on select human malignancies. Here, we report that the tumor suppressor protein p53 is downregulated during iron excess. Strikingly, the iron polyporphyrin heme binds to p53 protein, interferes with p53-DNA interactions, and triggers both nuclear export and cytosolic degradation of p53. Moreover, in a tumorigenicity assay, iron deprivation suppressed wild-type p53-dependent tumor growth, suggesting that upregulation of wild-type p53 signaling underlies the selective efficacy of iron deprivation. Our findings thus identify a direct link between iron/heme homeostasis and the regulation of p53 signaling, which not only provides mechanistic insights into iron-excess-associated tumorigenesis but may also help predict and improve outcomes in iron-deprivation-based chemotherapy

    A high serum creatine kinase (CK)-MB-to-total-CK ratio in patients with pancreatic cancer: a novel application of a traditional marker in predicting malignancy of pancreatic masses?

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    Abstract Background The finding that some benign pancreatic masses mimic the imaging appearance of carcinomas poses a challenge for pancreatic surgeons. Preoperative markers that assist in the diagnosis are critical under this circumstance. Abnormal serum creatine kinase (CK) isozyme levels were reported in cancer patients, and this study aimed to explore the potential value of the CK-MB-to-total-CK ratio (CK ratio) in differentiating pancreatic cancer (PC) from benign masses when combined with carbohydrate antigen 19-9 (CA19-9). Methods A total of 190 patients primarily diagnosed with pancreatic masses were retrospectively reviewed and assigned to the PC group and the benign pancreatic mass (BPM) group. Sixty-eight controls were enrolled for comparison. Levels of preoperative parameters, including total serum CK, CK-MB, absolute neutrophil count, absolute lymphocyte count, albumin, and CA19-9, were recorded as well as pathological information. A logistic regression model was established to assess the application value of the combination of CA19-9 and the CK ratio in diagnosis. Receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic value of the markers. Results The CK ratio was significantly elevated in the PC group compared with the BPM group (P < 0.001). In the multivariate analysis, a CK ratio greater than 0.220 was a statistically significant variable for predicting malignancy of pancreatic masses (P=0.001). Patients with stage III/IV PC had a higher CK ratio than those with stage I/II PC (P<0.01). Combined detection of CA19-9 and the CK ratio produced an increased Youden index (0.739 vs. 0.815) with improved sensitivity (82.2% vs. 89.8%). Conclusions The CK ratio is elevated in patients with pancreatic adenocarcinoma and is an independent factor predicting pancreatic adenocarcinoma. The CK ratio augments the diagnostic capacity of CA19-9 in detecting malignancy
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