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Portable infusion pumps are an interesting solution to continue outpatient parenteral antimicrobial therapy (OPAT) at the patient's home. However, the use of ceftazidime for such applications is challenging in view of its relatively poor stability in solution. In this study, elastomeric infusion pumps with 6 or 7 g of ceftazidime were deflated over 24 h in an oven at 33°C while ceftazidime and its degradation product, pyridine, were regularly monitored. Hereto, a fast and sensitive liquid chromatographic (LC) method has been developed using a Kinetex® C18 (150 × 3 mm, 2.6 μm) column with gradient elution. Ammonium formate 20 mM and acetonitrile (ACN) were mixed in a ratio of 98:2 v/v for mobile phase A and 85:15 v/v for mobile phase B. Both were adjusted to pH 4.5 with formic acid. The flow rate was set at 0.4 mL/min. The solution with a starting dose of 6 g ceftazidime was found to be degraded 10% after an average of 19 h 11 min so that an administration of 6 g to the patient was not reached. For the solution with a starting dose of 7 g of ceftazidime, 10% degradation was observed after an average of 18 h 42 min. However, by starting from a higher dose, an average of 6.56 g of ceftazidime could be administered over 24 h. In addition, 1.0% of pyridine versus ceftazidime pentahydrate with sodium carbonate (=mixture for injection) was formed over 24 h.

Predicting dynamic nitrate fluxes at the catchment scale is relevant to understand solute transport processes, assess eutrophication risks and improve water quality management. In order to simplify the complex biogeochemical processes without disregarding the spatial heterogeneity and changing flow paths, we combine physical modeling and a conceptual transit time approach. First, we use the physically-based, 3D, spatially distributed hydrologic model HydroGeoSphere (HGS) to extract transit time distributions (TTDs) of a conservative tracer for different parts of a catchment (partitioned by land use). We systematically combine different initial and boundary conditions analyzing apparent changes in shape and scale of the TTDs. Then we modify the resulting land use-specific TTDs according to the typical decay and retardation processes that are associated with nitrate. This includes retention of organic nitrogen, as well as attenuation by plant uptake and denitrification of inorganic nitrate. Finally, we superimpose and convolve the time series of nitrate-specific TTDs to compute the total nitrate outflux from the catchment.

Influence of the Trommsdorff–Norrish (T–N) effect on the phase separation of methyl methacrylate (MMA)/poly(ethyl acrylate) (PEA) mixtures undergoing photo-polymerization was examined by a combination of several experimental techniques. By FT-IR spectroscopy, it was found that the polymerization conversion explosively increases at the onset of this T–N effect. The characteristic irradiation time τ at which this effect occurs, strongly depends on the light intensity and gradually shifts to early time as the irradiation intensity increases. The shrinkage of the mixture observed in situ by laser-scanning confocal microscopy exhibits a transition at a particular irradiation time which is slightly longer than the characteristic time τ. By gel permeation chromatography (GPC), it was found that the molecular weight of the resulting PMMA was almost unchanged before τ and suddenly increases about an order of magnitude after the onset of the auto-acceleration effect. Finally, the characteristic length scales of the morphology also quickly increase with irradiation time and are eventually frozen by this T–N effect. These experimental results indicate that the Trommsdorff–Norrish effect plays an important role in the kinetic processes of polymerization-induced phase separation, suggesting an efficient tool to control the morphology of the polymerizing mixture.

Enhanced photorefractive (PR) performances are reported for a PR composite of perylene bisimide (PBI)–sensitized poly(4-(diphenylamino)benzyl acrylate) (PDAA), 2-(4-(azepan-1-yl)benzylidene)malononitrile (7-DCST), and (4-(diphenylamino)phenyl)methanol (TPAOH). The addition of a large amount of the TPAOH photoconductive plasticizer was found to produce a preferred hole manifold that reduces the disordered state. A photorefractive performance with a minimum response time of 11 ms, a maximum external diffraction efficiency of 41.6%, a maximum sensitivity of 117 cm2 J−1, and a maximum optical gain of 296 cm−1 were obtained with an external electric field of 55 V μm−1 for PDAA/7-DCST/TPAOH/PBI (30/30/39.9/0.1 by wt.).