Reacting equimolar quantities of 5-allenyl-1,3-benzenedicarboxylic acid (H 2 abd ) with lead( ii ) acetate trihydrate in N , N -dimethylformamide (DMF) under solvothermal conditions results in ...formation of a metallogel with a critical gelation percentage of 1% w/v. Elemental analysis performed on the gel provided a molecular composition ratio of Pb( abd )(H 2 O) n ( 1 ). Viewing the gel by scanning electron microscopy (SEM) identified an entangled network of cross-linked nano-fibres. 1 H-NMR aliquots of hydrated lead( ii ) acetate added to a solution of H 2 abd in deuterated DMF allows inferences to be made about solution-state behaviour that occurs during the initial gel aggregation stage. Under non-solvothermal conditions, combining H 2 abd and hydrated lead( ii ) acetate resulted in formation of single crystals suitable for X-ray diffraction, which were identified as a 3D coordination polymer with composition Pb( abd )(DMF) ( 2 ). Structural features observed within this 3D coordination polymer provide the basis for assigning the molecular structure to the fibrils present within gel 1 . This assertion is supported by comparable vibrational profiles taken from a sample of dried gel 1 to that of crystalline 2 , and the matching of early solution-state 1 H-NMR spectroscopic trends to later solid-state observations.
The process of placental implantation involves a series of transformations of trophoblast from a single polarized epithelial layer resting on a basement membrane (villous trophoblast), to cellular ...aggregates (trophoblast columns) which ultimately disperse to invade uterine decidua as individual cells (interstitial trophoblast). Such tissue re-modelling is associated with changes in the constituents of the extracellular matrix and in the expression of matrix receptors by the cells, the most relevant being the family of integrins which bind to laminin and fibronectin. In this study we show, by immunohistology and flow cytometry, a gradual loss of laminin receptors with the concomitant acquisition of fibronectin receptors as trophoblast is transformed from the villous phenotype, through the cell columns, into the extravillous population. The pattern of staining for the alpha 5, alpha 6, beta 1 and beta 4 subunits indicates that the integrins expressed by trophoblast are predominantly the alpha 5 beta 1 and the alpha 6 beta 4 heterodimers. We have also shown that isolated trophoblast cells assume a flattened, sessile phenotype when cultured on laminin but exhibit a more spreading, motile morphology when plated on fibronectin. In addition, numerous multinucleated giant cells are observed on a fibronectin substrate. Our data suggest that the relative expression of laminin and fibronectin receptors may determine the morphology and behaviour of trophoblast during the process of implantation.
As the dairy industry continues to grow, more dairy calves are available for dairy, beef, and veal purposes. Rearing systems must be highly efficient to make this industry cost efficient, making the ...evaluation of rearing methods important to establish the most practical method. A study was designed and conducted to evaluate effects of housing and feeding systems on performance of neonatal Holstein bull calves. Treatments (2 × 2 factorial arrangement) consisted of: 1) individually housed, bottle-fed (n = 5 bull calves); 2) individually housed, bucket-fed (n = 5 bull calves); 3) group-housed, bottle-fed (n = 5 pens; 4 bull calves/pen); and 4) group-housed, bucket- (trough) fed (n = 5 pens; 3 or 4 bull calves/pen). Feeding treatments began on d 7 when calves had been acclimated to their new environment. Body weight measurements were collected every 7 d and blood samples were collected on d 0, 28, 55, and 66 for β-hydroxybutyrate (BHBA) concentration as a gross indicator of ruminal development. No housing × feeding interactions or feeding treatment effects were observed (P > 0.10). Average DMI (dry feed plus milk replacer) was increased (P < 0.05) for group-housed vs. individual animals after d 41, and final BW was greater (P < 0.05) for group-housed calves compared with individually housed calves. Feed efficiency and ADG, however, remained similar (P > 0.10) for all treatments. Fecal scores (P > 0.26), CV for BW (P > 0.26), and BHBA concentrations (P > 0.14) showed no differences among treatments. Housing system had greater effect on calf performance compared with milk feeding regimen.
Alprazolam has proven efficacy as a treatment for panic disorder, but the place of other benzodiazepines is less well established.
To compare the efficacy and tolerability of diazepam and alprazolam ...for the disorder, a placebo-controlled, double-blind trial was undertaken in two sites. Two hundred forty-one subjects with panic disorder or agoraphobia with panic attacks were randomly assigned to flexible doses of diazepam, alprazolam, or placebo for 8 weeks.
At the end of the trial, over 60% of subjects taking either diazepam or alprazolam were at least moderately improved compared with less than 30% of those taking placebo. On all measures of efficacy, subjects taking diazepam and alprazolam showed an equally favorable response. Despite some sedation early in the trial, both drugs were tolerated well. More severely ill subjects responded less well to either benzodiazepine.
The results indicate that diazepam is an effective alternative to alprazolam for the treatment of panic disorder.
Pulse radiolysis has been used to generate high triplet populations on isolated conjugated polymer chains in benzene solutions. This allows direct observation of delayed fluorescence (DF) arising ...from intramolecular triplet–triplet annihilation (TTA). In poly(2-methoxy,5-(2
′-ethyl-hexyloxy)-
p-phenylenevinylene) the triplet lifetime at low triplet concentration is 90 μs which decreases to 15 μs as the number of triplets saturates at ca. 30 triplets per chain. Analysis of the DF kinetics gives an upper limit of 1.5% for the number of triplets that contribute to TTA. We also observed DF in a range of other conjugated polymers.
We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and γ-ray bands, with additional 5GHz ...flux-density limits to ensure a good probability of a Planck detection. We compare our results to those of a companion paper presenting simultaneous Planck and multi-frequency observations of 104 radio-loud northern active galactic nuclei selected at radio frequencies. While we confirm several previous results, our unique data set allows us to demonstrate that the selection method strongly influences the results, producing biases that cannot be ignored. Almost all the BL Lac objects have been detected by the Fermi Large AreaTelescope (LAT), whereas 30% to 40% of the flat-spectrum radio quasars (FSRQs) in the radio, soft X-ray, and hard X-ray selected samples are still below the γ-ray detection limit even after integrating 27 months of Fermi-LAT data. The radio to sub-millimetre spectral slope of blazars is quite flat, with ⟨α⟩ ~ 0 up to about 70GHz, above which it steepens to ⟨α⟩ ~ −0.65. The BL Lacs have significantly flatter spectra than FSRQs at higher frequencies. The distribution of the rest-frame synchrotron peak frequency (νpeakS) in the spectral energy distribution (SED) of FSRQs is the same in all the blazar samples with ⟨νpeakS⟩ = 1013.1 ± 0.1 Hz, while the mean inverse Compton peak frequency, ⟨νpeakIC⟩, ranges from 1021 to 1022 Hz. The distributions of νpeakS and νpeakIC of BL Lacs are much broader and are shifted to higher energies than those of FSRQs; their shapes strongly depend on the selection method. The Compton dominance of blazars, defined as the ratio of the inverse Compton to synchrotron peak luminosities, ranges from less than 0.2 to nearly 100, with only FSRQs reaching values larger than about 3. Its distribution is broad and depends strongly on the selection method, with γ-ray selected blazars peaking at ~7 or more, and radio-selected blazars at values close to 1, thus implying that the common assumption that the blazar power budget is largely dominated by high-energy emission is a selection effect. A comparison of our multi-frequency data with theoretical predictions shows that simple homogeneous SSC models cannot explain the simultaneous SEDs of most of the γ-ray detected blazars in all samples. The SED of the blazars that were not detected by Fermi-LAT may instead be consistent with SSC emission. Our data challenge the correlation between bolometric luminosity and νpeakS predicted by the blazar sequence.
Multinuclear ((1)H, (13)C and (27)Al) magnetic resonance spectroscopy (1D and 2D), DFT calculations and fluorescence have been used to study the complexation of 8-hydroxyquinoline-5-sulfonate (8-HQS) ...with Al(III). The study combines the high sensitivity of luminescence techniques, the selectivity of multinuclear NMR spectroscopy with the structural details accessible through DFT calculations, and aims to provide a detailed understanding of the complexation between the Al(3+) ion and 8-HQS. A full speciation study has been performed and over the concentration region studied, the Al(3+) ion forms complexes with 8-HQS in an aqueous solution in the pH range 2-6. At higher pH, the extensive hydrolysis of the metal limits complexation. Using Job's method, three complexes were detected, with 1 : 1, 1 : 2 and 1 : 3 (metal : ligand) stoichiometries. These results are in agreement with those previously reported using potentiometric and electrochemical techniques. The geometries of the complexes are proposed based on the combination of NMR results with optimized DFT calculations. All the complexes in aqueous solutions at 25 °C are mononuclear species, and have an approximately octahedral geometry with the metal coordinated to one molecule of 8-HQS and four molecules of water (1 : 1 complex), two molecules of 8-HQS and two molecules of water mutually cis (1 : 2 complex), and to three molecules of 8-HQS in non-symmetrical arrangement (mer-isomer), for the 1 : 3 (metal : ligand) complex. On binding to Al(III), 8-HQS shows a more marked fluorescence than the weakly fluorescent free ligand. In addition, as previously noted, there are marked changes in the absorption spectra, which support the use of 8-HQS as a sensitive optical sensor to detect Al(3+) metal ions in surface waters and biological fluids. These complexes also show potential for applications in organic light emitting diodes (OLEDs).
...I see crisis as a significant turning point, marked by an event that reveals the instability of a concept that immediate, decisive change is needed or often demanded. ...of the discourse of ...crisis, current-traditional rhetoric created a curriculum that served the interest of the professional classes who wanted writing that was technical and formally correct. ...in this case the rhetoric of disciplinary crisis contains racial and cultural undertones: it was been built on determining whose writing was better, and whose writing was better was, in part, determined from linguistic determinations by and from certain racial and economic privileged groups. ...Teresa Redd's Revelations: An Anthology of Expository Essays by and about Blacks was a textbook for students at Howard University that highlighted Black people writing essays about the Black experience for Black students.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Five intensities of artificial light were examined for the effect on nocturnal melatonin concentrations. Maximum suppression of melatonin following 1 hr of light at midnight was 71%, 67%, 44%, 38%, ...and 16% with intensities of 3,000, 1,000, 500, 350, and 200 lux (lx), respectively. In contrast to some previous reports, light of 1,000 lx intensity was sufficient to suppress melatonin to near daytime levels, and intensities down to 350 lx were shown to significantly suppress nocturnal melatonin levels below prelight values. On the basis of these data, it is suggested that when examining the melatonin sensitivity of patient groups (such as bipolar affective disorders) to artificial light, an appropriate light intensity should be established in each laboratory. Light of less intensity (e.g., 200-350 lx) may be more suitable to dichotomize patient groups from control subjects.
PDF
