Association between hospital case volume and the use of bronchoscopy and esophagoscopy during head and neck cancer diagnostic evaluation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102212/1/cncr28379.pd

Optimizing accuracy and efficacy in data-driven materials discovery for the solar production of hydrogen

The production of hydrogen fuels, via water splitting, is of practical relevance for meeting global energy needs and mitigating the environmental consequences of fossil-fuel-based transportation. Water photoelectrolysis has been proposed as a viable approach for generating hydrogen, provided that stable and inexpensive photocatalysts with conversion efficiencies over 10% can be discovered, synthesized at scale, and successfully deployed (Pinaud et al., Energy Environ. Sci., 2013, 6, 1983). While a number of first-principles studies have focused on the data-driven discovery of photocatalysts, in the absence of systematic experimental validation, the success rate of these predictions may be limited. We address this problem by developing a screening procedure with co-validation between experiment and theory to expedite the synthesis, characterization, and testing of the computationally predicted, most desirable materials. Starting with 70 150 compounds in the Materials Project database, the proposed protocol yielded 71 candidate photocatalysts, 11 of which were synthesized as single-phase materials. Experiments confirmed hydrogen generation and favorable band alignment for 6 of the 11 compounds, with the most promising ones belonging to the families of alkali and alkaline-earth indates and orthoplumbates. This study shows the accuracy of a nonempirical, Hubbard-corrected density-functional theory method to predict band gaps and band offsets at a fraction of the computational cost of hybrid functionals, and outlines an effective strategy to identify photocatalysts for solar hydrogen generation

Sex stereotypes influence adults' perception of babies' cries

Background: Despite widespread evidence that gender stereotypes influence human parental behavior, their potential effects on adults’ perception of babies’ cries have been overlooked. In particular, whether adult listeners overgeneralize the sex dimorphism that characterizes the voice of adult speakers (men are lower-pitched than women) to their perception of babies’ cries has not been investigated. Methods: We used playback experiments combining natural and re-synthesised cries of 3 month-old babies to investigate whether the interindividual variation in the fundamental frequency (pitch) of cries affected adult listeners’ identification of the baby’s sex, their perception the baby’s femininity and masculinity, and whether these biases interacted with their perception of the level of discomfort expressed by the cry. Results: We show that low-pitched cries are more likely to be attributed to boys and high-pitched cries to girls, despite the absence of sex differences in pitch. Moreover, low-pitched boys are perceived as more masculine and high-pitched girls are perceived as more feminine. Finally, adult men rate relatively low-pitched cries as expressing more discomfort when presented as belonging to boys than to girls. Conclusion: Such biases in caregivers’ responses to babies’ cries may have implications on children’s immediate welfare and on the development of their gender identity

Metal Ruthenate Perovskites as Heterogeneous Catalysts for the Hydrolysis of Ammonia Borane

Ammonia borane (NH₃-BH₃) is of interest as a hydrogen storage material because of its ease of use and its ability to release three molar equivalents of H₂(g) via catalytic hydrolysis. Most heterogeneous catalysts for ammonia borane hydrolysis are nanoparticles containing expensive noble metals. Here, we show that metal ruthenate perovskites function as active and durable catalysts for ammonia borane hydrolysis. As a bulk powder, CaRuO₃ catalyzes the hydrolysis of ammonia borane at room temperature and is recyclable and reusable. CaRuO₃ facilitates the release of H₂(g) from aqueous ammonia borane solutions at comparable rates to some other heterogeneous catalyst systems while having a low noble metal content. Other ruthenium-based perovskites, including SrRuO₃, Ca₂LaRuO₆, Sr₂CoRuO₆, and SrLaCoRuO₆, are similarly active catalysts for room-temperature ammonia borane hydrolysis

Synthesis and Characterization of Amorphous Bibenzoate (Co)polyesters: Permeability and Rheological Performance

Melt polycondensation of bibenzoate dimethyl esters with ethylene glycol enabled the synthesis of polyesters containing linear (4,4′-bibenzoate (4,4′BB)) and kinked (3,4′-bibenzoate (3,4′BB)) repeating units. Novel 3,4′BB:4,4′BB (co)­polyesters with ethylene glycol (EG) showed an onset of weight loss (<i>T</i>_d,5%) above 350 °C. ¹H NMR spectroscopy confirmed 4,4′BB:3,4′BB incorporation, and size exclusion chromatography (SEC) revealed high molecular weights. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) revealed glass transition temperatures (<i>T</i>_g) approaching 121 °C, crystallization and melting transition temperatures (<i>T</i>_c and <i>T</i>_m), and sub-<i>T</i>_g β-relaxations. 4,4′BB incorporation below ∼45 mol % afforded an amorphous morphology, while 4,4′BB incorporation above 45 mol % induced crystallinity. Melt rheology elucidated the effect of structure on flow behavior, and time–temperature superposition (TTS) revealed distinct flow transitions. TTS analysis also provided insight into the structural influence of regioisomers on fractional free volume (<i>f</i>_g) and flow activation energies (<i>E</i>_a). Incorporation of the symmetrical 4,4′BB monomer negligibly affected the <i>f</i>_g but imparted a stiffer overall chain, resulting in higher <i>E</i>_a. Positron annihilation lifetime spectroscopy (PALS) of the (co)­polyesters confirmed a lack of change in free volume through measuring the average free volume of a spherical hole. Determination of oxygen permeability offered fundamental understanding of the relationship of monomer symmetry with gas permeability and free volume in unoriented films; kinked 3,4′BB monomer afforded higher overall barrier in amorphous films. Finally, tensile testing elucidated Young’s moduli and yield strengths, confirming (co)­polyesters’ mechanical similarity to BPA-polycarbonate. Moduli ≤2.7 GPa and yield strengths up to 74 MPa confirmed BB-based (co)­polyesters enhanced properties compared to other high-<i>T</i>_g polyesters

Influence of Bibenzoate Regioisomers on Cycloheanedimethanol-Based (Co)Polyester Structure-Property Relationships

Melt polymerization enabled the synthesis of semi-aromatic (co)polyesters containing 1,4-cyclohexanedimethanol (CHDM), 4,4′-bibenzoate (4,4′BB), and 3,4′-bibenzoate (3,4′BB). Proton nuclear magnetic resonance (1H NMR) spectroscopy confirmed monomer incorporation, and size exclusion chromatography (SEC) revealed molecular weights and polydispersity indices (PDIs) consistent with high conversion melt phase synthesized polyesters. All bibenzoate-based polyesters exhibited a high onset of 5 wt % loss temperature according to thermogravimetric analysis (TGA) (\u3e350 °C), and differential scanning calorimetry (DSC) provided compositionally dependent glass transition temperatures (Tgs) approaching 135 °C and crystalline melting temperatures where applicable. Dynamic mechanical analysis (DMA) probed sub-Tg β-relaxations with minimal changes in intensity, suggesting that cyclohexyl ring relaxations dominated the low temperature energy absorption for all (co)polyester compositions. Time–temperature superposition (TTS) analysis from melt rheology revealed increasing characteristic relaxation times with increasing 4,4′BB content, which was attributed to the linear 4,4′BB stiffening the polymer chain. Increased kinked 3,4′BB content promoted chain entanglement, resulting in a lower entanglement molecular weight and a higher number of entanglements per chain (N/Ne). Similarly, increases in 3,4′BB content improved tensile yield strength and Young’s modulus due to a higher polymer density and potentially due to an increase in entanglement density. Finally, scanning electron microscopy (SEM) suggested mostly brittle failure after necking and strain hardening in tensile specimens. As a result, structure–property relationships afforded insight into regioisomer impacts on thermal, rheological, and mechanical performance for bibenzoate-based (co)polyester regioisomers

Crystalline Cobalt Oxide Films for Sustained Electrocatalytic Oxygen Evolution under Strongly Acidic Conditions

Earth-abundant materials capable of catalyzing the electrochemical decomposition of water into molecular hydrogen and oxygen are necessary components of many affordable water-splitting technologies. However, water oxidation catalysts that facilitate sustained oxygen evolution at device-relevant current densities in strongly acidic electrolytes have been limited almost exclusively to precious metal oxides. Here, we show that nanostructured films of cobalt oxide (Co₃O₄) on fluorine-doped tin oxide (FTO) substrates, made by first depositing Co onto FTO and heating in air at 400 °C to produce films having a robust electrical and mechanical Co₃O₄/FTO interface, function as active electrocatalysts for the oxygen evolution reaction (OER) in 0.5 M H₂SO₄. The Co₃O₄/FTO electrodes evolve oxygen with near-quantitative Faradaic yields and maintain a current density of 10 mA/cm² for over 12 h at a moderate overpotential of 570 mV. At lower current densities that require lower overpotentials, sustained oxygen production for several days and weeks can be achieved