Template Synthesis of Three-Dimensional Cubic Ordered Mesoporous Carbon With Tunable Pore Sizes

Three-dimensional cubic ordered mesoporous carbons with tunable pore sizes have been synthesized by using cubic Ia3d mesoporous KIT-6 silica as the hard template and boric acid as the pore expanding agent. The prepared ordered mesoporous carbons were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption analysis. The results show that the pore sizes of the prepared ordered mesoporous carbons with three-dimensional cubic structure can be regulated in the range of 3.9–9.4 nm. A simplified model was proposed to analyze the tailored pore sizes of the prepared ordered mesoporous carbons on the basis of the structural parameters of the silica template

Lineshape Measurements of Rotational Line in Millimeter-Wave Region by Second Harmonic Detection

Lineshape measurements of the J = 6 ← 5 OCS rotational transition were performed using a source-modulation microwave spectrometer. This is a very useful experimental technique but it introduces distortions to the line profile, therefore several authors have theoretically analyzed this problem with the aim of extracting the undistorted parameters of the spectra. The objective of this paper is to verify one of these theories which gives the relationship between harmonic signals and lineshape over wide range of modulation depth. Detailed comparison between the calculated and experimental harmonic signals shows very good agreement, and thus enables us to determine the unmodified line width and finally the pressure broadening factor of the rotational transition J = 6 ← 5 of OCS molecule to be equal to 6.59 ± 0.25 MHz/Tr

Pressure Broadening Measurements of J=6⇒7 Rotational Line of the t-Butyl Cyanide Molecule

Self-broadened width of J = 6⇒7 rotational line in the ground state of t-butyl cyanide molecule has been measured at room temperature. The measurements of the linewidth as a function of the gas pressure were carried out with home-made spectrometer at the frequency ν$\text{}_{0}$ = 38 498.308 MHz. The mean value of the pressure-broadening coefficient c = 76.9 ± 0.6 MHz Torr$\text{}^{-1}$ was obtained

Temperature Dependence of Pressure Broadened Linewidth of J = 1 ⇐ 0 Rotational Transition of CH3\text{}_{3}C14\text{}_{14}N Molecule Mixed with OCS and H2\text{}_{2} Molecule

The temperature dependence of the pressure-broadening parameters of the J = 1 ⇐ 0 rotational transition of OCS and H$\text{}_{2}$ in the ground vibrational state of CH$\text{}_{3}$C$\text{}_{14}$N molecule is measured in the temperature range between 248 and 293 K. The line shape of the absorption is recorded with a Stark modulated microwave spectrometer. Using least squares fits of the data to the Voigt line function, several contributions to the linewidth have been deduced. The experimental results are compared with the calculated results using Murphy and Boggs collision broadening theory. The pressure-broadening parameters C$\text{}_{W}$(x) of the gas mixture CH$\text{}_{3}$CN+OCS and CH$\text{}_{3}$CN+H$\text{}_{2}$ are 14.05±0.30 MHz/Tr, 9.15±0.12 MHz/Tr, respectively and the temperature dependence parameters α are -0.90 ± 0.07 and -0.77 ± 0.08

TEMPERATURE DEPENDENCE OF PRESSURE BROADENED LINEWIDTH OF J =1 = O ROTATIONAL TRANSITION OF CH3C 14 N MOLECULE MIXED WITH OCS AND H2 MOLECULE

The temperature dependence of the pressure-broadening parameters of the J = 1 O rotational transition of OCS and H2 in the ground vibrational state of CH3C 14 N molecule is measured in the temperature range between 248 and 293 K. The line shape of the absorption is recorded with a Stark modulated microwave spectrometer. Using least squares fits of the data to the Voigt line function, several contributions to the linewidth have been deduced. The experimental results are compared with the calculated results using Murphy and Boggs collision broadening theory. The pressure-broadening parameters CW (x) of the gas mixture CH3CN+OCS and CH3CN-+H2 are 14.05f 0.30 MHz/Tr, 9.15f 0.12 MHz/Tr, respectively and the temperature dependence parameters a are -0.90 ± 0.07 and -0.77 ± 0.08

Collisional Broadening of the J=7 ⇐ 6 Transition of t-Butyl Cyanide by CH3\text{}_{3}CN, OCS, CO2\text{}_{2} and Helium

Experimental studies of the broadening of the absorption line J = 6 ⇒ 7 of (CH$\text{}_{3}$)$\text{}_{3}$CCN due to collisions with the foreign perturbers He, CO$\text{}_{2}$, OCS, and CH$\text{}_{3}$CN have been carried out. The magnitude of the broadening coefficients reflects the type of interactions occurring in the molecular collisions. It has been concluded that the dipole-dipole and dipole-quadrupole interactions are predominant in the (CH$\text{}_{3}$)$\text{}_{3}$CCN admixed with CH$\text{}_{3}$CN and OCS. In the collisions between (CH$\text{}_{3}$)$\text{}_{3}$CCN and CO$\text{}_{2}$ the dipole-quadrupole interactions are present whereas the He perturbed by (CH$\text{}_{3}$)$\text{}_{3}$CCN exhibits dispersive type of interactions

Pressure Broadening of J=1 ← 0 Rotational Line of Fluoroform Caused by Spherical Perturbers

The foreign-gas broadening parameter was measured for CHF$\text{}_{3}$ molecule interacting with spherical (SF$\text{}_{6}$, CF$\text{}_{4}$, CH$\text{}_{4}$, CCl$\text{}_{4}$) perturbers and the pressure shift parameter of rotational transition J=1 ← 0 in the CHF$\text{}_{3}$ molecule was obtained. For the systems of trifluoromethane molecule and four spherical molecules as perturbers the collision cross-sections were determined. Experimental line width parameters are interpreted using Anderson-Tsao-Curnutte as well as Murphy-Boggs theories. Accounting for the dispersive and inductive interactions the cross-section was determined. The theoretical values are in qualitative agreement with the experimental results, but the absolute values of the measured cross-section were larger than these calculated

Directed Differentiation of Human Embryonic Stem Cells into Prostate Organoids <i>In Vitro</i> and its Perturbation by Low-Dose Bisphenol A Exposure

<div><p>Studies using rodent and adult human prostate stem-progenitor cell models suggest that developmental exposure to the endocrine disruptor Bisphenol-A (BPA) can predispose to prostate carcinogenesis with aging. Unknown at present is whether the embryonic human prostate is equally susceptible to BPA during its natural developmental window. To address this unmet need, we herein report the construction of a pioneer <i>in vitro</i> human prostate developmental model to study the effects of BPA. The directed differentiation of human embryonic stem cells (hESC) into prostatic organoids in a spatial system was accomplished with precise temporal control of growth factors and steroids. Activin-induced definitive endoderm was driven to prostate specification by combined exposure to WNT10B and FGF10. Matrigel culture for 20–30 days in medium containing R-Spondin-1, Noggin, EGF, retinoic acid and testosterone was sufficient for mature prostate organoid development. Immunofluorescence and gene expression analysis confirmed that organoids exhibited cytodifferentiation and functional properties of the human prostate. Exposure to 1 nM or 10 nM BPA throughout differentiation culture disturbed early morphogenesis in a dose-dependent manner with 1 nM BPA increasing and 10 nM BPA reducing the number of branched structures formed. While differentiation of branched structures to mature organoids seemed largely unaffected by BPA exposure, the stem-like cell population increased, appearing as focal stem cell nests that have not properly entered lineage commitment rather than the rare isolated stem cells found in normally differentiated structures. These findings provide the first direct evidence that low-dose BPA exposure targets hESC and perturbs morphogenesis as the embryonic cells differentiate towards human prostate organoids, suggesting that the developing human prostate may be susceptible to disruption by <i>in utero</i> BPA exposures.</p></div