534 research outputs found
Lanthanide Identity Governs Guest-Induced Dimerization in LnIII[15-MCCuIIN(L-pheHA)-5])3+ Metallacrowns
Series of lanthanide-containing metallic coordination complexes are frequently presented as structurally analogous, due to the similar chemical and coordinative properties of the lanthanides. In the case of chiral (LnIII[15-MC (Formula presented.) N(L-pheHA)-5])3+ metallacrowns (MCs), which are well established supramolecular hosts, the formation of dimers templated by a dicarboxylate guest (muconate) in solution of neutral pH is herein shown to have a unique dependence on the identity of the MC's central lanthanide. Calorimetric data and nuclear magnetic resonance diffusion studies demonstrate that MCs containing larger or smaller lanthanides as the central metal only form monomeric host-guest complexes whereas analogues with intermediate lanthanides (for example, Eu, Gd, Dy) participate in formation of dimeric host-guest-host compartments. The driving force for the dimerization event across the series is thought to be a competition between formation of highly stable MCs (larger lanthanides) and optimally linked bridging guests (smaller lanthanides)
Blood cyanide determination in two cases of fatal imtoxication: comparison between headspace gas chromatography and a spectrophotometric method
Blood samples of two cases were analyzed preliminarily by a classical spectrophotometric method (VIS) and by an automated headspace gas chromatographic method with nitrogen-phosphorus detector (HS-GC \u2044 NPD). In the former, hydrogen cyanide (HCN) was quantitatively
determined by measuring the absorbance of chromophores forming as a result of interaction with chloramine T. In the automated HS-GC \u2044NPD method, blood was placed in a headspace vial, internal standard (acetonitrile) and acetic acid were then added. This resulted in cyanide being liberated as HCN. The spectrophotometric (VIS) and HS-GC\u2044NPD methods were validated on postmortem blood samples fortified with potassium cyanide in the ranges 0.5\u201310 and 0.05\u20135 lg \u2044 mL, respectively. Detection limits were 0.2 lg \u2044mL for VIS and 0.05 lg \u2044mL for HS-GC\u2044NPD. This work shows that results obtained by means of the two procedures were insignificantly different and that they compared favorably. They are suitable for rapid diagnosis of cyanide in postmortem cases
A Unique LnIII{[3.3.1]GaIII Metallacryptate} Series That Possesses Properties of Slow Magnetic Relaxation and Visible/NearâInfrared Luminescence
A new family of [3.3.1] metallacryptates with the general composition [LnGa6(H2shi)(Hshi)(shi)7(C5H5N)] (Lnâ1; shi3â=salicylhydroximate; Ln = Pr, Nd, SmâYb) has been synthesized and characterized. Lnâ1 display both interesting magnetic and luminescent properties. Smâ1 has sharp emission bands in the visible and the nearâinfrared (NIR) regions with quantum yield values (QSmL) of 1.64(9) and 5.5(2).10â2â%, respectively. Tbâ1 exhibits a weak green emission (QTbL=1.89(3).10â1â%) while Prâ1, Ndâ1, Hoâ1, Erâ1, and Ybâ1 possess emission bands in the NIR range with QPrL=3.7(2).10â3â%, QNdL=1.71(5).10â1â%, QHoL=1.1(2).10â3â%, QErL=7.1(2).10â3â% and QYbL=0.65(3)â%. Ndâ1, Dyâ1, and Ybâ1 display slow magnetization relaxation in an applied field, where only Dyâ1 has been observed to follow an Orbach process (Ueff=12.7â
K). The combination of NIR emission with magnetic properties makes Ndâ1 and Ybâ1 attractive candidates as smart materials addressable in two manners.A twoâforâone scaffold: A new LnIIIâencapsulating metallamacrocyclic scaffold was synthesized and structurally determined to resemble cryptands. This metallacryptand can bind a wide variety of LnIII ions of different natures and demonstrates the ability to sensitize their characteristic emissions in the visible and/or nearâinfrared. Slow magnetic relaxation was also observed for selected LnIII.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145255/1/chem201801355.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145255/2/chem201801355_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145255/3/chem201801355-sup-0001-misc_information.pd
Facile preparation of CuBi2O4/TiO2 hetero-systems employed for simulated solar-light selective oxidation of 4-methoxybenzyl alcohol model compound
The selective photocatalytic oxidation of organic substances is today considered one of the green techniques to synthesize important starting materials in different technological applications. This work reports an efficient, simple and cheap strategy for the synthesis of a new photocatalytic CuBi2O4-TiO2 (CBO/TiO2) heterosystem at room temperature. The prepared powders were characterized by X-ray diffraction (XRD), UVâVis diffuse reflectance spectra (DRS), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The photocatalytic activity was evaluated by performing a probe reaction, namely the partial oxidation of 4-methoxybenzyl alcohol (4-MBA) to 4-methoxybenzaldehyde (4-MBAld) in aqueous solution under irradiation of simulated sunlight. The CBO/TiO2 coupled systems showed a higher photoactivity than the single photocatalysts reaching a selectivity of 45% towards 4âmethoxy-benzaldehyde with an alcohol conversion of 77% after 4 h of irradiation. Furthermore, although a high alcohol conversion was achieved, the selectivity towards 4-MBAld was significant, unlike what has been reported in the literature for many heterogeneous photocatalytic reactions whose selectivity generally decreases significantly with the increasing conversion of the starting alcohol molecule. The improved photocatalytic activity could be attributed to the partial coverage of the TiO2 surface by CBO which reduces the subsequent oxidation of the formed aldehyde
Histamine plasma levels and elimination diet in chronic idiopathic urticaria
Abstract: Objective: The aim of this study was to evaluate the effects of an oligoantigenic and histamine-free diet on patients affected with chronic idiopathic urticaria (CIU).
Design: Ten patients with chronic idiopathic urticaria were prescribed an oligoantigenic and histamine-free diet for 21 days, followed by serial and controlled reintroduction of foods during a further 70 days. Modification in clinical illness as well as histamine plasma levels, post-heparin plasma diamine oxidase (DAO) and intestinal permeability were evaluated.
Results: The oligoantigenic and histamine-free diet induced a significant improvement of symptoms (P < 0.05). Moreover, CIU patients on free diet showed higher histamine plasma levels (P < 0.05 vs post-diet and vs controls) that fell to control levels during the oligoantigenic and histamine-free diet. Post-heparin plasma diamine oxidase values were slightly reduced and were unchanged during the diet as well as intestinal permeability, which was always normal in all patients.
Conclusions: These data suggest that histamine plays a major role in chronic idiopathic urticaria. The finding of normal intestinal permeability suggests that a morphological damage of intestinal mucosa should be excluded in these patients. However, the presence of low levels of post-heparin plasma diamine oxidase may indicate a subclinical impairment of small bowel enterocyte function that could induce a higher sensitivity to histamine-rich or histamine-producing food
Efficacy of Muscle Exercise in Patients with Muscular Dystrophy: A Systematic Review Showing a Missed Opportunity to Improve Outcomes
Background:Although muscular dystrophy causes muscle weakness and muscle loss, the role of exercise in the management of this disease remains controversial. Objective:The purpose of this systematic review is to evaluate the role of exercise interventions on muscle strength in patients with muscular dystrophy. Methods:We performed systematic electronic searches in Medline, Embase, Web of Science, Scopus and Pedro as well as a list of reference literature. We included trials assessing muscle exercise in patients with muscular dystrophy. Two reviewers independently abstracted data and appraised risk of bias. Results:We identified five small (two controlled and three randomized clinical) trials comprising 242 patients and two ongoing randomized controlled trials. We were able to perform two meta-analyses. We found an absence of evidence for a difference in muscle strength (MD 4.18, 95% CIs - 2.03 to 10.39; p = 0.91) and in endurance (MD -0.53, 95% CIs -1.11 to 0.05; p = 0.26). In both, the direction of effects favored muscle exercise. Conclusions:The first included trial about the efficacy of muscular exercise was published in 1978. Even though some benefits of muscle exercise were consistently reported across studies, the benefits might be due to the small size of studies and other biases. Detrimental effects are still possible. After several decades of research, doctors cannot give advice and patients are, thus, denied basic information. A multi-center randomized trial investigating the strength of muscles, fatigue, and functional limitations is needed. \ua9 2013 Gianola et al
Low cancer yield in PI-RADS 3 upgraded to 4 by dynamic contrast-enhanced MRI: is it time to reconsider scoring categorization?
Objectives: To evaluate MRI diagnostic performance in detecting clinically significant prostate cancer (csPCa) in peripheral-zone PI-RADS 4 lesions, comparing those with clearly restricted diffusion (DWI-score 4), and those with equivocal diffusion pattern (DWI-score 3) and positive dynamic contrast-enhanced (DCE) MRI. Methods: This observational prospective study enrolled 389 men referred to MRI and, if positive (PI-RADS 3 with PSA-density [PSAD] â„ 0.15Â ng/mL/mL, 4 and 5), to MRI-directed biopsy. Lesions with DWI-score 3 and positive DCE were classified as âPI-RADS 3up,â instead of PI-RADS 4. Univariable and multivariable analyses were implemented to determine features correlated to csPCa detection. Results: Prevalence of csPCa was 14.5% and 53.3% in PI-RADS categories 3up and 4, respectively (p < 0.001). MRI showed a sensitivity of 100.0%, specificity 40.9%, PPV 46.5%, NPV 100.0%, and accuracy 60.9% for csPCa detection. Modifying the threshold to consider MRI positive and to indicate biopsy (same as previously described, but PI-RADS 3up only when associated with elevated PSAD), the sensitivity changed to 93.9%, specificity 57.2%, PPV 53.0%, NPV 94.8%, and accuracy 69.7%. Age (p < 0.001), PSAD (p < 0.001), positive DWI (p < 0.001), and PI-RADS score (p = 0.04) resulted in independent predictors of csPCa. Conclusions: Most cases of PI-RADS 3up were false-positives, suggesting that upgrading peripheral lesions with DWI-score 3 to PI-RADS 4 because of positive DCE has a detrimental effect on MRI accuracy, decreasing the true prevalence of csPCa in the PI-RADS 4 category. PI-RADS 3up should not be upgraded and directed to biopsy only if associated with increased PSAD. Key Points: âą As per PI-RADS v2.1 recommendations, in case of a peripheral zone lesion with equivocal diffusion-weighted imaging (DWI score 3), but positive dynamic contrast-enhanced (DCE) MRI, the overall PI-RADS score should be upgraded to 4. âą The current PI-RADS recommendation of upgrading PI-RADS 3 lesions of the peripheral zone to PI-RADS 4 because of positive DCE decreased clinically significant prostate cancer detection rate in our series. âą According to our results, the most accurate threshold for setting indication to prostate biopsy is PI-RADS 3 or PI-RADS 3 with positive DCE both associated with increased PSA density
Long-Term Outcomes of Diabetic Patients With Critical Limb Ischemia Followed in a Tertiary Referral Diabetic Foot Clinic
We describe the long-term outcomes of 510 diabetic patients with critical limb ischemia (CLI) and an active foot ulcer or gangrene, seen at the University Hospital of Rome Tor Vergata, a tertiary care clinic
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