Ions In Suspension Research Articles

The influence of metal ions on aqueous dispersions of graphite oxide

ABSTRACT The residual metallic impurities in the graphite oxide (GO) dominate their properties and have a negative influence on the potential applications. The swelling of the GO suspensions is mainly affected by electrostatic forces and special interactions between water molecules, metal ions and hydrophilic groups. Bivalent and trivalent cations give rise to ionic crosslinking of the charged network within the particles. The CaCl2 solution has the best purification effect. A new purification method is proposed in the purification process, the origin metal ions in GO suspensions are replaced by homogeneous metal ions first, and GO suspensions are desalted by electrodialysis device. Free ionic calcium is removed by electrodialysis, and only the calcium that interact with GO particles is remained. The content of fixed calcium is 0.0049 g/g (nearly clear) after washing with 1.5 mmol/L CaCl2 solution and electrodialyzing for 20 min. The new method improves the purification efficiency and save energy.

In Vitro Cytotoxicity and Pharmacokinetic Study for Bosutinib Solid Lipid Nanoparticles.

Bosutinib (BST) is a Biopharmaceutics Classification System Class II drug having very low solubility and high permeability. Low aqueous solubility and poor dissolution of BST lead to poor bioavailability, Thus, limited aqueous solubility is the bottleneck for the therapeutic outcome of BST. Animal data suggest that the absolute bioavailability of BST is about 14-34% due to an extensive first-pass effect. To overcome hepatic first-pass metabolism and to enhance oral bioavailability, lipid-based drug delivery systems such as solid lipid nanoparticles (SLNs) can be used. SLNs are submicron colloidal carriers having a size range of 50-1000 nm. These are prepared with physiological lipid and dispersed in water or aqueous surfactant solution. BST can be conveniently loaded into SLNs to improve the oral bioavailability by exploiting the intestinal lymphatic transport. An optimal system was evaluated for bioavailability study in rats compared with that of BST suspension (SUS). An in vitro cytotoxicity study was done by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay method through ATCC cell lines; the percent inhibition was more in SLN when compared with SUS. The pharmacokinetics of BST-SLNs after oral administration in male Wistar rats was studied. The bioavailability of BST was increased by 2.28 fold when compared with that of a BST SUS. The results are indicative of SLNs as suitable lipid-based carrier system for improving the oral bioavailability of BST.

Single-bubble sonoluminescence of itterbium(II or III) and thulium(II or III) chloride nanoparticles colloidal suspensions in dodecane

Colloidal suspensions of nanoparticles of di- and trivalent ytterbium and thulium chloride crystals in dodecane were prepared by ultrasonic dispersion. The average nanoparticle size in the suspensions was 20–35 nm. During single-bubble sonolysis with the bubble moving at the standing wave antinode, identical bands with a maximum at 550 nm appeared in the sonoluminescence spectra with spectral resolution Δλ = 15 nm for suspensions of both Yb(II) and Yb(III) salts. Bands with a maximum at 600 nm were found for suspensions of Tm(II) and Tm(III) salts. These sonoluminescence bands coincide with the photoluminescence bands of Yb(II) (550 nm) or Tm(II) (600 nm) salts, respectively. For suspensions of divalent lanthanide salts, these sonoluminescence bands appear when nanoparticles get into a moving bubble, because of collisional excitation of Yb(II) or Tm(II) in the bubble plasma, which periodically appears during acoustic oscillations: [Ln(II)]suspension → [Ln(II)]bubble → [Ln(II)]plasma → [Ln(II)*]plasma → Ln(II) + hνLn(II). The presence of analogous bands for suspensions of trivalent lanthanide salts is caused, in particular, by also their reduction in the plasma after they get into a bubble: [Ln(III)]suspension → [Ln(III)]bubble → [Ln(III)]plasma → [Ln(II), Ln(II)*]plasma → [Ln(II)*]plasma → Ln(II) + hνLn(II). The reduction of lanthanide ions in the bubble plasma is not limited to the reaction Ln(III) → Ln(II), Ln(II)*, but can proceed further giving singly charged lanthanide cations and lanthanide atoms: Ln(II) → Ln(I), Ln(I)* → Ln(0), Ln(0)*. The single-bubble sonoluminescence spectra with Δλ = 1.5 nm for a suspension of Yb(III) salt showed characteristic lines of Yb(I) and Yb(0). These characteristic lines and bands for ytterbium and thulium atoms and ions are suitable for sonoluminescent spectroscopic analysis, that is, identification and quantification of ions in solutions and suspensions and determination of electronic temperature in bubble plasma.

Tailored coordination chemistry: A novel Zn(II)-fluorescent coordination material for highly selective and sensitive detection of Hg2+ ions in aqueous environments

The pursuit of advanced sensing materials for precisely detecting heavy metal ions remains a critical imperative in environmental science. This manuscript deal with a novel fluorescent material, ZU-1, designed for the selective and sensitive detection of Hg2+ ions in aqueous suspension. Employing the Hard-Soft Acid-Base (HSAB) concept, Zn2+ serves as the d10 metal ion, and ZU-1 is synthesized with a −S donor ligand (NaSCN) and 2-pyridine methanol (Hhmp). The fluorescence sensing elucidates a unique detection mechanism, unveiling the distinctive coordination facilitated by the larger ionic radius and soft acid characteristics of Hg2+ with the −S donor sites in ZU-1. Fluorescence titration experiments validate ZU-1’s outstanding ability to selectively quench fluorescence intensity in the presence of Hg2+, even amidst interference from other metal ions. The quantitative analysis yields a Stern-Volmer constant (Ksv) of 7.5 × 108 M−1 and an exceptional limit of detection for Hg2+ at ∼0.60 ppm. ZU-1 further distinguishes itself through outstanding recyclability over four cycles, underscoring its potential as a sustainable and reusable sensor for real-time Hg2+ detection. Beyond its practical implications, this research contributes fundamental insights into design principles for materials exhibiting heightened selectivity and sensitivity to heavy metal ions.

Meta-pharmacokinetic analysis of posaconazole following dosing of oral suspension, delayed-release tablet, and intravenous infusion in patients vs. healthy volunteers: Impact of clinical characteristics and race

ObjectivesTo investigate the potential impact of clinical characteristics and the Chinese race on posaconazole pharmacokinetics in patients using an integrated population pharmacokinetic model for posaconazole oral suspension (SUS), delayed-release tablet (DR-tablet), and intravenous (IV) infusion that was developed in healthy volunteers (HV). Methods1046 concentrations from 105 prospectively studied Caucasian patients receiving either of the three posaconazole formulations were pooled with 3898 concentrations from 182 HV. Clinical characteristics were tested for significance. The impact of Chinese race was assessed using 292 opportunistic samples from 80 Chinese patients receiving SUS. ResultsBioavailability of SUS (Fsus) in patients decreased from 38.2% to 24.6% when the dose was increased from 100 mg to 600 mg. Bioavailability of DR-tablet (Ftab) was 59% regardless of dose. Mucositis, diarrhoea, administration through a nasogastric tube, and concomitant use of proton pump inhibitors or metoclopramide reduced Fsus by 61%, 36%, 44%, 48%, and 29%, respectively, putting patients with these characteristics at increased risk of inadequate exposure. Clearance decreased from 7.0 to 5.1 L/h once albumin levels were <30 g/L. Patients showed an 84.4% larger peripheral volume of distribution (Vp) and 67.5% lower intercompartmental clearance (Q) compared with HV. No racial difference could be identified. ConclusionsPharmacokinetics of posaconazole in patients differ considerably to those in HV, with altered Fsus that is also impacted by clinical covariates, an Ftab similar to fasted conditions in HV, and altered parameters for clearance, Vp, and Q. There was no evidence to indicate that Chinese patients require a different dose to Caucasian patients.

Photoactive Ce-doped TiO2 and CeO2-TiO2 composite coatings deposited by suspension/solution plasma spray

In this work, Ce-doped TiO2 coatings were produced using a hybrid suspension (SPS) and solution precursor plasma spraying (SPPS) approach. CeO2-TiO2 composite coatings were also deposited by the SPS process. The photocatalytic activity of the coatings was evaluated by measuring the methylene blue degradation rate under visible light. Cerium doping and CeO2 composite coatings were characterized by X-ray diffractometer measurements and verified by energy dispersive spectroscopy mapping, Raman spectra, and X-ray photoelectron spectroscopy analysis. The hybrid SPS/SPPS technique presented a promising method to deposit doped ceramic coatings among thermal spray processes. According to the results, modifying TiO2 coatings decreased the bandgap of TiO2 from 3.25 to 2.3 eV using cerium dopant. However, a lower photocatalytic efficiency of TiO2 -CeO2 composite and Ce-doped TiO2 coatings compared to TiO2 could be related to the lower active surface area of TiO2 covered by submicron CeO2 particles and non-optimal dosage of cerium dopant, respectively.

Low doses of pharmaceutical formulations loaded with UFMG-V4N2 immunogen induce the production of IgG anti-cocaine antibodies and provide evidence of cerebral protection in the preclinical model

Anti-cocaine vaccines are a promising therapeutic strategy for treating cocaine use disorders. Here we hypothesize that nanoemulsions (NE) or suspensions (SS) loaded with the calix [4]arene-based immunogen UFMG-V4N2 can induce the production of anti-cocaine antibodies and decrease the passage of radiolabeled cocaine analog [99mTc]Trodat-1 through of the brain barrier. UFMG-V4N2 was characterized (solubility, morphology, DSC, XRD) and loaded into NEs and SSs using excipients approved for human use. Immunogenic efficacy was assessed by quantifying the titers and determining the specificity of anti-cocaine IgG antibodies, and by assessing the inhibition of [99mTc]Trodat-1 trafficking across the mice brain-barrier. UFMG-V4N2 is an amorphous, thermally stable molecule with very low hydrophilicity. The immunogenicity of NE or SS was similar, but aluminum phosphate and the lower dose of UFMG-V4N2 induced higher anti-cocaine IgG antibody titers, minimizing [99mTc]Trodat-1 uptake in the brain. Therefore, the UFMG-V4N2 may represent an alternative for the treatment of cocaine use disorder.

Improved photocatalytic conversion of high−concentration ammonia in water by low−cost Cu/TiO2 and its mechanism study

Platinized TiO2 (Pt/TiO2) as a benchmark photocatalyst shows superior photocatalytic performance in environmental remediation. In order to reduce the cost of photocatalyst for practical use, a series of cooper loaded TiO2 (Cu/TiO2) photocatalysts were prepared by photoreduction method and compared with pure TiO2 and Pt/TiO2 in terms of overall ammonia conversion efficiency and selective oxidation. The as−prepared Cu/TiO2 samples were characterized and analyzed by physicochemical instrumental measurements. The results show that about 60% Cu2+ ions in suspension can be photodeposited onto the surface of TiO2 under UV light irradiation, and is mainly composed by a mixture of Cu/Cu+. The Cu/P25 (0.3 wt% Cu) sample was screened out as the optimal photocatalyst, via photoilluminance spectra analysis and photocatalytic oxidation of ammonia. It shows even better performance compared to Pt/TiO2 in the oxidation of high concentration of ammonia, due to the strong coordination effect by Cu(NH3)n complex formation. Through Electron Spin Resonance (EPR) analysis, and free radical suppression experiments, the active oxidative species account for ammonia oxidation and selective product generation were analyzed, and the possible reaction mechanisms involving photocatalytic ammonia conversion were proposed. ●OH has been identified as the main oxidant that affects the removal efficiency of ammonia nitrogen, whereas O2●− mainly affects the production of N2 and h+ is mainly responsible for the production of NO3−. These results indicate that Cu/TiO2 could be used as a low−cost and efficient photocatalyst in pretreatment process for conversion of high concentration of ammonia in wastewater.

Photolysis of Neptunium Ions in HCOOH Solutions

Spectrophotometric method has been used to examine valence transformations of neptunium ions in formi acid aqueous solutions under the action of light from a mercury lamp. It was shown that Np(VI) ions are reduced in ~10 min to Np(IV) containing a small amount of (Np(V). Np(V) ions in solutions and suspensions are also effectively reduced to Np(IV). Np(III) appears in a photolysis of Np(IV) ions. In 99.7% HCOOH, the Np(IV) → Np(III) conversion occurs nearly fully. Np(III) ions are unstable and are transformed to Np(IV) in storage. The hydrolysis and polymerization of Np(IV) hinder the reduction of Np(IV) in1 M HCOOH.

The Radiational Chemical Reduction of Silver Ions in Water Suspensions of Poly(vinyltriazole): The Kinetic Peculiarities of the Formation of Nanoparticles

The radiational chemical production of silver nanoparticles offers promising prospects for the synthesis of the antibacterial materials in the matrix of the nontoxic poly(vinyltriazole). Use of the optical spectroscopy for the electronic transmission microscopy shows that nanoparticles of the average size of 4 nm are formed in the radiated suspensions of poly(1-vinyl-1,2,4-triazole). The analysis of the data of the optical spectroscopy reveals that nanoparticles are formed in several stages. At the first stage, the formation of clusters is prevalent and the second stage provides the assembly of nanoparticles through the reduction of silver ions on the surface of the clusters.

A self-penetrated three-dimensional zinc(II) coordination framework based on 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzoic acid and 1,3-bis[(imidazol-1-yl)methyl]benzene ligands: synthesis, structure and properties.

With the rapid development of metal-organic frameworks (MOFs), a variety of MOFs and their derivatives have been synthesized and reported in recent years. Commonly, multifunctional aromatic polycarboxylic acids and nitrogen-containing ligands are employed to construct MOFs with fascinating structures. 4,4',4''-(1,3,5-Triazine-2,4,6-triyl)tribenzoic acid (H3TATB) and the bidentate nitrogen-containing ligand 1,3-bis[(imidazol-1-yl)methyl]benzene (bib) were selected to prepare a novel ZnII-MOF under solvothermal conditions, namely poly[[tris{μ-1,3-bis[(imidazol-1-yl)methyl]benzene}bis[μ3-4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzoato]trizinc(II)] dimethylformamide disolvate trihydrate], {[Zn3(C24H12N3O6)2(C14H14N4)3]·2C3H7NO·3H2O}n (1). The structure of 1 was characterized by single-crystal X-ray diffraction, IR spectroscopy and powder X-ray diffraction. The properties of 1 were investigated by thermogravimetric and fluorescence analysis. Single-crystal X-ray diffraction shows that 1 belongs to the monoclinic space group Pc. The asymmetric unit contains three crystallographically independent ZnII centres, two 4,4',4''-(1,3,5-triazine-2,4,6-triyl)tribenzoate (TATB3-) anions, three complete bib ligands, one and a half free dimethylformamide molecules and three guest water molecules. Each ZnII centre is four-coordinated and displays a distorted tetrahedral coordination geometry. The ZnII centres are connected by TATB3- anions to form an angled ladder chain with large windows. Simultaneously, the bib ligands link ZnII centres to give a helical Zn-bib-Zn chain. Furthermore, adjacent ladders are bridged by Zn-bib-Zn chains to form a fascinating three-dimensional self-penetrated framework with the short Schläfli symbol 65·7·813·9·10. In addition, the luminescence properties of 1 in the solid state and the fluorescence sensing of metal ions in suspension were studied. Significantly, compound 1 shows potential application as a fluorescent sensor with sensing properties for Zr4+ and Cu2+ ions.

A double-well potential model for the ionic electrokinetic polarization in low concentration cell suspensions

In order to understand the effects of cells on the ionic electrokinetic polarization process in cell suspensions, a double-well potential electrokinetic polarization model for ions in cell suspensions under a pressure gradient field is established with reference to the ionic double-well potential model in dielectric polarization. By analyzing the ionic electrokinetic polarization process in the double-well potential, the relation between the electrokinetic polarization field of the ions in the well potential and the external pressure gradient field is derived. The “repression effect” of cell concentration on the ionic electrokinetic polarization voltage is theoretically analyzed, and the mechanisms of the effects of cells on the ionic electrokinetic polarization are obtained. The electrokinetic polarization voltages of the suspensions with different concentrations of rabbit blood cell in phosphate buffer solution are measured. The experiment results showed that the ionic electrokinetic polarization voltage decreased with increased cell concentration in the range of 105~ 107/ml, which is consistent with the theoretical models. The experiment has shown the validity of the double-well potential model for cell suspensions of low concentration. Our research deepens the understanding of the mechanism of electrokinetic polarization of cell suspensions, and provides a new model for using electrokinetic polarization to analyze the charge characteristics on cell surface.

Effect of Spirulina platensis suspension on quality and quantity of sperm and expression of caspase-3 of testis in diabetic wistar rats induced by streptozotocin

Diabetes is metabolic disorders caused by oxidative stress that has always been linked to male reproductive dysfunction. Spirulina platensis has been used for therapeutic supplements for diabetes and repairing reproduction organs based on its antioxidant effects. The aim of this study was to examine the effect of Spirulina platensis suspension (SP) on quality and quantity of sperm also the expression of caspase-3 on testis in male Wistar rats induced by streptozotocin (STZ). This study used 30 adult male Wistar rats that divided into 6 groups of K1 (normal), K2 (single injection of STZ 45 mg/kg BW), K3 (normal rats treated with SP 36/kg BW/day) and treatment group K4, K5 and K6 were diabetic rats given with SP 36 mg/kgBW, 72 mg/kgBW and 144 mg/kg BW. The treatment was given orally for 28 days. Blood glucose level levels were measured using the biochemical analyzer. Quality and quantity of sperm were analyzed using Neubauer slide under the microscope. Apoptosis of Leydig cells was detected by immunohistochemical staining using Caspase-3 polyclonal antibodies. The result showed that there were significant differences between groups (p < 0.05) in final blood glucose level, quality, and quantity of spermatozoa and expression of caspase-3. Our findings clearly highlight the role of Spirulina platensis as an antidiabetes and protective agent for reproducton organs of STZ-induced in diabetic male Wistar rats that improves quality and quantity of sperm cells and reproductive organs.

A lanthanide complex for selective sensing of Fe(III) ions

The lanthanide complex [Eu(Tpy–NH2)2Cl2]Cl (1), where Tpy–NH2 is 4-(paminophenyl)-2,2:6,2”-terpyridine, was synthesized. Its photophysical properties, e.g., Fourier Transform Infrared (FTIR) spectra, UV–visible absorption spectra, and luminescence properties, in the presence of various metal ions were studied. Tpy-NH2 acts as chromophore, or light-harvesting photo sensitizing antenna moiety, for Eu3+ luminescence. The bright luminescence in 1 suggests that favourable photo-induced energy transfer occurs from the Tpy-NH2 antenna to the Eu3+ to fill the long-lived emissive excited states of Eu3+ f–f transitions. The luminescence spectral profile of complex 1 showed a characteristic sharp emission band maximum for 5D0 →7F2 f–f transitions at 614 nm originating from Eu3+ ions. The luminescence studies revealed that this material possesses a highly selective fluorescence quenching response to Fe3+ ions in liquid suspension. The dose-dependent fluorescent quenching showed good linearity, and a Fe3+ detection limit of 0.655 μM was calculated for complex 1. This material can potentially be used as a fluorosensor for sensing Fe3+ ions; its luminescence quenching response can be explained in terms of a competitive absorption mechanism.

Role of sodium carbonate in scheelite flotation – A multi-faceted reagent

Even though sodium carbonate is a reagent frequently used in flotation, its role is mostly described as a buffering pH modifier and a pulp dispersant. In the case of scheelite flotation, literature has shown that sodium carbonate improves flotation performance but little is said as to selectivity against gangue minerals. There is a consensus that sodium carbonate neutralizes calcium-bearing minerals through surface carbonation but this does not explain why it should depress said minerals in a specific order. Furthermore, the addition of depressants such as sodium silicate or quebracho could be triggering new mechanisms. Through batch flotation testwork on a skarn scheelite ore, single mineral flotation and contact angle measurements, this article aims at demonstrating that sodium carbonate is a multi-faceted reagent, which serves as a buffering pH modifier, a pulp dispersant precipitating calcium ions in suspension and a depressant for calcite and calcium-bearing silicates. Based on the kinetics, calcium surface site density, calcium activity and surface reactions, fluorite would be the first mineral to be depressed, then calcite, then silicates and finally scheelite and possibly apatite if sodium carbonate is overdosed, likely independently from pH and definitely independently from the co-pH modifier. Sodium silicate acts mostly synergistically and partially antagonistically with other depressants, notably sodium silicate and quebracho.

Partitioning of Ag and CeO2 nanoparticles versus Ag and Ce ions in soil suspensions and effect of natural organic matter on CeO2 nanoparticles stability

This study examined the solid-liquid distribution of 14.8-nm Ag and 6.2-nm CeO2 nanoparticles in soil suspensions and compared it to that of Ag+ and Ce3+ ions, to better understand their environmental behaviour and fate. After 24 h incubation, more than 51% or 29% of the spiked amounts of Ag or CeO2 nanoparticles, respectively, can be retrieved in the liquid phase of (re)suspended soils. The Ag or Ce concentration remaining in solution depends on the incubation time and was influenced by soil properties. Significant correlations are obtained between, on the one hand, the relative amounts of Ag or CeO2 nanoparticles in suspension and the soil-pH, CEC, texture, suspended matter, nitrogen, phosphorus, TOC and main and trace elements content on the other hand. The presence of dissolved natural organic matter stabilizes CeO2 nanoparticles in the aqueous phase. In soil suspensions, Ag+ and Ce3+ ions seemingly interact more strongly with soil constituents compared to their nanoparticle counterparts, rendering the Ag and CeO2 nanoparticles to be more stable and potentially bioavailable.

Mycobacterium avium complex: Adherence as a way of life.

Mycobacterium avium complex (MAC) organisms are waterborne, opportunistic pathogens whose source is natural waters and soils and proliferates and persists in premise plumbing, for example household and hospital plumbing. M. avium complex and other environmental mycobacteria grow slowly, not because their metabolism is slow, but because they synthesize long chain (C60–C80) fatty acids that make up its hydrophobic and impermeable outer membrane. There are costs and benefits to the presence of that lipid-rich outer membrane. One benefit is that cell-surface hydrophobicity drives M. avium complex cells to adhere to surfaces to reduce their interaction with charged ions in suspension; they are likely “biofilm pioneers”, adhering to a wide variety of surface materials. The result is that the slow-growing M. avium complex cells (1 gen/day at 37 °C) will not be washed out of any flowing system, whether a stream or plumbing in the built environment. Although the slow permeation of nutrients in M. avium complex organisms limits growth, they are also resistant to disinfectants, thus increasing their survival in water distribution systems, premise plumbing, and medical equipment. There are three components to the antimicrobial resistance of M. avium complex in biofilms: (1) innate resistance due to the hydrophobic, impermeable outer membrane, (2) residence in a matrix of extracellular polysaccharide, lipid, DNA, and protein that prevents access of antimicrobials to M. avium cells, and (3) an adaptive and transient increased resistance of biofilm-grown M. avium cells grown in biofilms. As expected M. avium in biofilms will display neutral, antagonistic, or beneficial interactions with other biofilm inhabitants. Methylobacterium spp., the common pink-pigmented, waterborne bacteria compete with M. avium for surface binding, suggested an approach to reducing M. avium biofilm formation and hence persistence in premise plumbing.

Pure and Oxidized Copper Materials as Potential Antimicrobial Surfaces for Spaceflight Activities.

Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of antimicrobial activity. Key Words: Contact killing-E. coli-S. cohnii-Antimicrobial copper surfaces-Copper oxide layers-Human health-Planetary protection. Astrobiology 17, 1183-1191.

Therapeutic Drug Monitoring (TDM) of Suspension (SUS), Extended-Release (ER), and Intravenous (IV) Posaconazole (POS) at a Large Transplant Center

BackgroundData on ER and IV POS among organ transplant recipients (OTRs) are limited, and the role of TDM is unclear.MethodsRetrospective study of patients (pt) receiving any formulation of POS who had serum troughs checked. Therapeutic was defined as 3 1 mcg/mL.ResultsWe analyzed 88 pt and 340 levels (SUS: 88, ER: 197, IV: 55). Eighty-five pt were OTRs (97%), 73 were lung transplant recipients (LT) (83%), 17 had cystic fibrosis (CF) (19%). POS was used for treatment (70%) (probable aspergillosis (38%), possible aspergillosis (10%), mucormycosis (16%), other mycoses (6%)), prophylaxis (19%), and pre-emptive therapy (14%). POS was given for intolerance of or contraindication to other azoles (47%), salvage therapy (10%), resistance (19%), and failure to achieve therapeutic levels with other azoles (6%). Serum concentration/dose ratios were lower with SUS vs. ER/IV (P < 0.0001) but were similar in ER/IV groups (P = 0.51) (Figure). There was no difference in serum levels between pt receiving ER vs. IV POS at 300 mg once daily (median 1.2 vs. 1.3 mcg/mL, therapeutic 70% vs. 73%, P = 0.57 and >0.99, respectively). 3 pt had levels £ 0.2 mcg/mL on 300 mg ER: 2 had CF and had undergone LT (0.2 and 0 mcg/mL) and 1 had short-gut syndrome (0.1 mcg/mL). Sixty-six percent and 67 % of pt receiving ER or IV POS (300 mg once daily) achieved initial therapeutic levels, respectively; of these, 87% and 83% had median therapeutic follow-up levels, respectively. Serial levels were available for 7 pt whose dose was increased from 300 to 400 mg ER once daily for subtherapeutic levels. 4/7 pt achieved therapeutic levels on 400 vs. 0/7 on 300 mg ER once daily (P = 0.069). Metoclopramide use and CF were associated with subtherapeutic vs. therapeutic levels (25% vs. 4% and 37% vs. 13%, respectively, P = < 0.05). When pt with CF were excluded, neither age nor body mass index were associated with POS levels. CF pt had lower levels than non-CF pt on a dose of 300 mg ER once daily (median 0.8 vs. 1.3 mcg/mL, P = 0.018).ConclusionTherapeutic levels are more reliably achieved with ER & IV POS compared with SUS POS. Serial TDM is unnecessary for most, but is recommended for pt with CF or those on metoclopramide. Dose increases may effectively increase levels. Novel dosing strategies are needed for CF.Disclosures R. K. Shields, Astellas: Received research funding, Research support. Merck: Received research funding, Research support. C. J. Clancy, Merck: Received research funding, Research support. Astellas: Received research funding, Research support. Cidara: Received research funding, Research support. Astellas: Scientific Advisor, Advisory board. Merck: Scientific Advisor, Advisory board. Cidara: Scientific Advisor, Advisory board. Medicines Company: Scientific Advisor, Advisory board.

A Luminescent Terbium MOF Containing Hydroxyl Groups Exhibits Selective Sensing of Nitroaromatic Compounds and Fe(III) Ions

A new 3D porous Tb(III)-ion based PMOF, {[Tb(L)(DMA)]·(DMA)·(0.5H2O)} (1) (where L = L3–, H3L = 3′-hydroxybiphenyl-3,4′,5-tricarboxylic acid), with uncoordinated hydroxyl groups decorating the pores has been solvothermally synthesized in moderate yield. The hydroxyl groups act as potential interaction sites to sensitize the luminescence output of the Tb3+ ion. Luminescence studies reveal that the PMOF can selectively and reversibly sense nitroaromatic compounds and Fe(III) ions in DMF suspension through fluorescence quenching observable under UV light. The probable mechanisms for such sensing processes are, for the nitroaromatic compounds, the host–guest interactions with the PMOF and, for Fe3+ ion, the competitive absorption of excitation energy.