Numerous studies demonstrate that chow-fed rats learn to prefer flavors that are associated with the postingestive effects of nutrients. The rats» limited dietary experience (i.e. only lab chow) may ...have facilitated preference learning because of the novelty of the training stimuli. This possibility was investigated by comparing nutrient conditioning in rats fed chow or a varied “cafeteria” diet. Rats in Experiment 1 were trained during alternate sessions (30 min/day) to drink two different flavors paired with concurrent intragastric infusions of 16% Polycose or water. Both diet groups displayed similarly strong preferences (89%) for and increased acceptance of the Polycose-paired flavor. A more demanding learning task was used in Experiment 2: new flavors were paired with delayed (15 min) infusions of Polycose or water. The chow and cafeteria groups both showed reduced, but comparable (78%, 77%) preferences for the Polycose-paired flavor. In Experiment 3, new flavors were paired with concurrent infusions of 7·1% corn oil or water. Again, the cafeteria and chow groups developed similar preferences for the nutrient-paired flavor (85%, 78%). Also, both groups preferred the Polycose-paired flavor of Experiment 1 to the oil-paired flavor of Experiment 3 (76%, 78%). These results indicate that dietary variety does not interfere with nutrient-conditioned flavor preference learning in rats.
In the wake of climate change from rising CO2 emissions and with peak oil looming, the dive into sustainable fuels and energy is becoming increasingly essential. This dissertation investigates ...ternary ligand-metal cationic complexes for potential catalytic applications in the decarboxylation of carboxylic acids to produce bioavailable and carbon-neutral fuel sources. By utilizing gas-phase reactivity studies via mass spectrometry, namely, collision-induced dissociation and ion-molecule reactions, mechanisms can be elucidated in a regulated chemical environment. When paired with density functional theory calculations for molecular geometries, chemical interactions, charge densities, and energetics, system efficiencies can be further clarified presenting a more complete mechanistic and catalytic analysis. Previous work by our group demonstrated the strength of the catalytic production of hydrogen from formic acid with (L)ZnH+, where L = 1,10-phenanthroline (phen) or 2,2′:6′,2″-terpyridine (terpy), 2,2-bipyridine (bipy). Similar chelates and multidentate nitrogenous ligands were attempted using (terpy)ZnH+ as a comparative standard. The ion (L)Zn(OOCH)+ (where L = tris(pyridin-2-ylmethyl)amine (TPMA), N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN), 1,4,7-triazonane (9-N-3), tri(pyridin-2-yl)phosphine (TPP), tri(pyridin-2-yl)phosphine oxide (TPPO), di-(2-picolyl)amine (DPA)) is formed in solution, introduced into the mass spectrometer, and subjected to collisional activation to generate the (L)ZnH+ species. The zinc hydride ion is then reacted with neutral formic acid inside the ion trap of the mass spectrometer to reproduce the (L)Zn(OOCH)+ ion through the loss of neutral H2 and thereby completing the formal catalytic cycle. All the ligands performed kinetically slower than the terpy standard, except for DPA which has the geometry most similar to terpy thus providing rationale for its similar reactivity. A secondary study compared the (terpy)ZnH+ system to other metals in the 1st transition row demonstrated the versatility of the terpy ligand as Fe(II) and Co(II) operated at similar reaction efficiencies and kinetics as Zn. Published studies by Boddien and co-workers on a cage iron-phospholigand complex’s ability to decarboxylate formic acid into hydrogen piqued the interest of our group. Our collaborators from the University of Portland synthesized several ligands with structural variances from the published work to produce comparable ternary complexes (L’)M(OOCH)+, where the synthetic ligands (L’) were tris(2-(diphenylphosphino)phenyl)phosphine (DPPP), tris((diphenylphosphino)methyl)phosphite (DPMP), and (((2-(methylthio)phenyl)phosphinediyl)bis(2,1 phenylene))bis (diphenylphosphine) (MPPD). The DPPP ligand did not form any complex ionic species of the form (L’)MH+ capable of ion-molecule reaction to generate hydrogen. Successful complexes were seen with Mn(II) and Zn and the MPPD ligand, and Fe(II) with the DPMP ligand. Ion-molecule reaction of the metal hydride (L’)MH+ with formic acid thereby providing a full formal catalytic cycle producing the (L’)M(OOCH)+ ion with molecular hydrogen had the trend of: (DPMP)FeH+ > (MPPD)MnH+ >> (MPPD)ZnH+. Theoretical calculations demonstrated molecular geometry and energetic calculations demonstrated the favorable nature of these systems. Crown ethers are known chelating agents with typically strong electron donating groups amongst their cyclic molecule cavity that form host-guest pairings with cationic species. Crown ethers therefore appeared to be an ideal choice in the hydrogen generation studies from formic acid. Herein, ions formed of the general ion (crown)M(OOCH)+ (where crown = 12-crown-4 (12c4), 15-crown-5 (15c5), and 18-crown-6 (18c6)) were activated through collision induced dissociation to form the metal hydride species (crown)MH+. Fragmentation in these systems produced very little side reactions, i.e., competitive reaction channels to the metal-hydride. Ion molecule reaction with formic acid with the Zn systems to establish the formal catalytic cycle and were shown to be kinetically slow with all iterations of crown tested, resulting in the following reactivity trend: 12c4 > 15c5 = 18c6 (with no ligand resulting in >1% reaction efficiency). Smaller metals in the first-row transition series were tested with the 12c4 ligand and ion-molecule reaction of the (12c4)MH+ species demonstrating that the overall reaction trend loosely followed periodic table atomic size trends: Mn=Co=Ni>Fe>>Cu>>Zn. Energy diagrams produced by theoretical calculations confirmed the reactivity seen in the experiments. The last chapter of the dissertation deals with the novel gas-phase catalytic systems from production of hydrocarbons from bioavailable fatty acid sources. The ion (terpy/phen)Zn(OOCR)+ after collisional activation demonstrated decarboxylation to form the alkylated (organozinc) cation (terpy/phen)Zn(R)+ (where R = C3H7, C6H13, C7H15, C17H35, C17H33, C17H31). From this ion two pathways could proceed: i.) a gas-phase ion-molecule reaction with a neutral carboxylic acid R’COOH resulting in the ion (terpy/phen)Zn(OOCR’)+ and the alkane RH; ii.) a second activation of the (terpy/phen)Zn(R)+ ion producing an alkene and the ion (terpy/phen)Zn(H)+ which underwent ion-molecule reaction with R’COOH to form (terpy/phen)Zn(OOCR’)+ and the accompanied H2 loss. When R=R’ the reaction is presented as two formal catalytic cycles as seen with butyric acid resulting in the overall equations: C3H7COOH = C3H8+ CO2 or C3H7COOH = C3H6 + H2+ CO2. This work presents Zn/N-ligand complexes as a potential catalyst for fatty acid deoxygenation with no fragmentation of the hydrocarbon chain, producing alkanes or terminal alkenes.
We study the estimation of the overlap between two unknown pure quantum states of a finite-dimensional system, given M and N copies of each type. This is a fundamental primitive in quantum ...information processing that is commonly accomplished from the outcomes of N swap tests, a joint measurement on one copy of each type whose outcome probability is a linear function of the squared overlap. We show that a more precise estimate can be obtained by allowing for general collective measurements on all copies. We derive the statistics of the optimal measurement and compute the optimal mean square error in the asymptotic pointwise and finite Bayesian estimation settings. Besides, we consider two strategies relying on the estimation of one or both states and show that, although they are suboptimal, they outperform the swap test. In particular, the swap test is extremely inefficient for small values of the overlap, which become exponentially more likely as the dimension increases. Finally, we show that the optimal measurement is less invasive than the swap test and study the robustness to depolarizing noise for qubit states.
We study the problem of transmitting classical information using quantum Gaussian states on a family of phase-noise channels with a finite decoherence time, such that the phase-reference is lost ...after
m
consecutive uses of the transmission line. This problem is relevant for long-distance communication in free space and optical fiber, where phase noise is typically considered as a limiting factor. The Holevo capacity of these channels is always attained with photon-number encodings, challenging with current technology. Hence for coherent-state encodings the optimal rate depends only on the total-energy distribution and we provide upper and lower bounds for all
m
, the latter attainable at low energies with on/off modulation and photodetection. We generalize this lower bound to squeezed-coherent encodings, exhibiting for the first time to our knowledge an unconditional advantage with respect to any coherent encoding for
m
=
1
and a considerable advantage with respect to its direct coherent counterpart for
m
>
1
. This advantage is robust with respect to moderate attenuation, and persists in a regime where Fock encodings with up to two-photon states are also suboptimal. Finally, we show that the use of part of the energy to establish a reference frame is sub-optimal even at large energies. Our results represent a key departure from the case of phase-covariant Gaussian channels and constitute a proof-of-principle of the advantages of using non-classical, squeezed light in a motivated communication setting.
Key Points
In situ uranyl phosphate precipitation is fast on the time scale of remediation
Ca2+ & SO42‐ affect uranyl phosphate precipitation rate and morphology
Only chernikovite is formed, and it ...blocks pore spaces and reduces mixing
The abiotic precipitation of uranium (U(VI)) was evaluated in a microfluidic pore network (i.e., micromodel) to assess the efficacy of using a phosphate amendment to immobilize uranium in groundwater. U(VI) was mixed transverse to the direction of flow with hydrogen phosphate (HPO42−), in the presence or absence of calcium (Ca2+) or sulfate (SO42−), in order to identify precipitation rates, morphology and types of minerals formed, and effects of mineral precipitates on pore blockage. Precipitation occurred over the time scale of hours to days. Relative to when only U(VI) and HPO42− were present, precipitation rates were 2.3 times slower when SO42− was present, and 1.4 times faster when Ca2+ was present; larger crystals formed in the presence of SO42−. Raman backscattering spectroscopy and micro‐X‐ray diffraction results both showed that the only mineral precipitated was chernikovite, UO2HPO4 · 4H2O; energy dispersive X‐ray spectroscopy results indicate that Ca and S are not incorporated into the chernikovite lattice. A pore‐scale model was developed, and simulation results of saturation ratio (SR = Q/Ksp) suggest that chernikovite is the least thermodynamically favored mineral to precipitate (0 < SR < 1) compared to uranyl hydrogen phosphate and Na‐autunite (13 < SR < 40), and uranyl orthophosphate and Ca‐autunite (when Ca2+ is present; SR > 105). Fluorescent tracer studies and laser confocal microscopy images showed that densely aggregated precipitates blocked pores and reduced permeability. The results suggest that uranium precipitation with phosphate as chernikovite is rapid on the time scale of remediation for the conditions considered and can block pores, alter fluid flow paths, and potentially limit mixing and precipitation.
Filgotinib is an oral small molecule that selectively inhibits JAK1. It is already approved for the treatment of moderately to severely active ulcerative colitis (UC). Ongoing studies are evaluating ...the efficacy and safety of filgotinib in Crohn's disease (CD). The purpose of this review is to summarize the available data regarding filgotinib in the management of UC and CD. We used Pubmed, Embase and clinicaltrials.gov websites to search all available data and currently ongoing studies regarding the efficacy and safety of filgotinib in inflammatory bowel diseases. Filgotinib is an effective and safe drug for the management of biologic-naive and biologic-experienced patients with moderate-to-severe UC. The same efficacy results have not been achieved in CD.
Abstract Background Laparoendoscopic single-site surgery (LESS) has been developed in an attempt to minimise the morbidity and scarring associated with surgical intervention. Objective To evaluate ...the incidence of and the risk factors for complications in patients undergoing LESS upper urinary tract surgery. Design, setting, and participants Between September 2007 and February 2011, 192 consecutive patients underwent LESS for upper urinary tract diseases at four institutions. Measurements All complications occurring at any time after surgery were captured, including the inpatient stay as well as in the outpatient setting. They were classified as early (onset <30 d), intermediate (onset 31–90 d), or late (onset >90 d) complications, depending on the date of onset. All complications were graded according to the modified Clavien classification. Results and limitations The patient population was generally young (mean: 55 ± 18 yr of age), nonobese (mean body mass index BMI: 26.5 ± 4.8 kg/m2 ), and healthy (mean preoperative American Society of Anaesthesiologists ASA score: 2 ± 1). Forty-six patients had had prior abdominal surgery. Mean operative time was 164 ± 63 min, with a mean estimated blood loss (EBL) of 147 ± 221 ml. In 77 cases (40%), the surgeons required additional ports, with a standard laparoscopy conversion rate of 6%. Mean hospital stay was 3.3 ± 2.3 d, and the mean visual analogue scale (VAS) score at discharge was 1.7 ± 1.43. Thirty-three complications were recorded—30 early, 2 intermediate, and 1 late—for an overall complication rate of 17%. Statistically significant associations were noted between the occurrence of a complication and age, ASA score, EBL, length of stay (LOS), and malignant disease at pathology. Univariable and the multivariable analyses showed that a higher ASA score (incidence rate ratio IRR: 1.4; 95% confidence interval CI, 1.0–2.1; p = 0.034) and malignant disease at pathology (IRR: 2.5; 95% CI, 1.3–4.7; p = 0.039) represented risk factors for complications. Poisson regression analysis over time showed a 23% non-statistically significant reduction in risk of complications every year (IRR: 0.77; 95% CI, 0.5–1.19; p = 0.242). Conclusions Malignant disease at pathology and high ASA score represent a predictive factor for complication after LESS for upper urinary tract surgery. Thus, surgeons approaching LESS should start with benign diseases in low-surgical-risk patients to minimise the likelihood of postoperative complications.
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