Radiolabelled Cyclic Bisarylmercury: High Chemical and in vivo Stability for Theranostics

We show the synthesis of an in vivo stable mercury compound with functionality suitable for radiopharmaceuticals. The designed cyclic bisarylmercury was based on the water tolerance of organomercurials, higher bond dissociation energy of Hg−Ph to Hg−S, and the experimental evidence that acyclic structures suffer significant cleavage of one of the Hg−R bonds. The bispidine motif was chosen for its in vivo stability, chemical accessibility, and functionalization properties. Radionuclide production results in ^197(m)HgCl₂(aq), so the desired mercury compound was formed via a water-tolerant organotin transmetallation. The Hg-bispidine compound showed high chemical stability in tests with an excess of sulfur-containing competitors and high in vivo stability, without any observable protein interaction by human serum assay, and good organ clearance demonstrated by biodistribution and SPECT studies in rats. In particular, no retention in the kidneys was observed, typical of unstable mercury compounds. The ^natHg analogue allowed full characterization by NMR and HRMS.     

Local governments' efficiency: a systematic literature review—part II

The efficient management of the available resources in local governments has been a topic of high interest in the field of public sector. We provide an extensive and comprehensive review of the existing literature on local governments' efficiency from a global point of view, covering all articles from 1990 to August 2016. This paper is the second of two. It covers the aspects related to local governments' efficiency measurement along with its determinants, that is, taking into account the effect of environmental variables over efficiency. First, we describe which techniques have been used to incorporate environmental variables in the context of local governments. Second, we provide a classification for the determinants used and summarize their impact on efficiency. Finally, we discuss some operative directions and considerations for further research in the field.     

A ratio or budget benchmark for comparing affordability across countries?

In this article, the methodological strengths and weaknesses of two common housing affordability indicators—the expenditure-to-income ratio and the residual income—are discussed, using data for the Belgian region of Flanders and the Netherlands. Affordability standards are used in order to distinguish the group facing affordability problems. In case of residual income, we use minimum budget standards—excluding housing—that allow for decent participation in society. For the expenditure-to-income ratio, we apply the internationally frequently used 30 % benchmark. Our comparison of the two methods results in a preference for the budget approach. Consequently, we explore the possibilities of applying the budget approach in a comparative context. We conclude by making recommendations for future research.     

Interconnect reliability - A study of the effect of dimensional and porosity scaling

A number of challenges linked to the reliability characterization of downscaled back-end-of-line copper/low-k interconnects are covered. Concerning copper reliability, it is shown using early data on 30 nm ½pitch that advanced barrier/seed/plating options can counteract models that predict decreased electromigration performance in smaller dimensions. Regarding stress-induced voiding, it is discussed that porosity scaling negatively influences metal degradation due to increased stress gradients. Also, since copper degradation during high temperature storage tests is driven by different failure mechanisms, it is argued that tests at a wide range of temperatures are needed to characterize stress-induced voiding in copper/low-k systems at normal operating conditions. In addition, it is suggested that the current knowledge on the dependence of interconnect pitches and dielectric porosity on stress in copper lines needs to be taken into account when building finite element models of copper/low-k stacks. This is motivated by highlighting results of our recent study where the copper strain is varied for different copper dimensions and pattern densities. Finally, because the reliability margin of time dependent dielectric breakdown of scaled intermetal dielectrics becomes smaller, it is put forward that understanding the low voltage behaviour of time dependent dielectric breakdown becomes indispensable. A case study using fully passivated MOS capacitors without metallic barrier between the copper and the dielectric is detailed out and differences in current versus time behaviour and distributional shapes between low and high fields are highlighted.     

Shelf-life extension of cooked ham model product by high hydrostatic pressure and natural preservatives

The inactivation of different spoilage organisms and surrogate pathogens in a cooked ham model product by high pressure (HP) treatment (100–700 MPa, 5–40 °C, 10 min) was investigated. A 5 log reduction could be achieved at ≥ 600 MPa at ≥ 25 °C. Subsequently, the shelf-life of packaged sliced product was studied during storage (7 °C) after treatment at 600 MPa (10 °C, 10 min) in combination with caprylic acid and Purasal^®. Without HP treatment, a plate count of 6 log CFU/g was reached after 40 days, both in presence and absence of antimicrobials. HP treatment delayed this initiation of spoilage to 59 days in absence of antimicrobials. However, microbial growth was completely suppressed during at least 84 days in the HP treated products containing caprylic acid or Purasal^®. HP treatment increased drip loss but had no or little effect on colour and sensorial evaluation by a taste panel. However, the antimicrobials had a negative influence on the flavour and aroma at the concentrations used.

Industrial relevance

With a steadily increasing number of commercial applications being introduced on the market, HP pasteurization is growing out of its infancy. To further support this development, there is a need of integrated studies that translate fundamental scientific findings from simplified laboratory model systems to the complexity and scale of real food products. In this work, we determined HP processing conditions to control spoilage and pathogenic bacteria in a cooked ham model product, and subsequently conducted a large pilot scale experiment comprising a total of 432 individual packages of sliced cooked ham product, in which the microbiological, physicochemical and sensorial quality was evaluated during refrigerated storage after HP treatment. In addition, the usefulness of the natural preservatives caprylic acid and lactate-diacetate as an additional hurdle was also studied. This study is one of the most comprehensive available in the literature to document the shelf-life extension that can be achieved with HP treatment of cooked ham.     

Separation of a triterpenoid saponin mixture from Maesa lanceolata: semipreparative reversed-phase wide pore high performance liquid chromatography with temperature control

A mixture of triterpenoid saponins derived from the dried leaves of Maesa lanceolata was separated, without structure deterioration, in its components. Seven fractions (I-VII) of high molecular weight (1234-1358) saponins were obtained on a semipreparative scale using wide pore reversed-phase high performance liquid chromatography with an acetonitrile trifluoroacetic acid (500:0.3 w/w)-water-trifluoroacetic acid (391:0.3, w/w) gradient from 35 to 56% in 30 min. The mobile phase was cooled in an ice bath (0 degrees C) during chromatography in order to prevent bubble formation and to improve the quality of the separation. Freeze-dried fractions IV, V, VI and VII were further separated using solvent systems developed for each of the fractions. Fourteen pure triterpenoid saponins were isolated in this way and their molar weight determined.     

Ernest Oberholtzer and the art of boundary crossing: writing,life and the narratives of conservation and planning

Through an analysis of the various roles of narrative in the life and work of famed conservationist Ernest C. Oberholtzer (1884–1977), we explore the relations between life (as evolving autobiographical narrative), place identity, and environmental planning, and the place of literary and artistic discourses in the processes of mutual articulation one can observe there. We investigate the role of writing in his work and life, and the functions of narratives in a broader sense, and argue that Oberholtzer's remarkable identification with a self-created place narrative, and his exceptional narrative fluidity, both in autobiographical sense and in other communicative situations, made him not only an exquisite wilderness advocate but also a rich source of insights into the narrative nature of environmental planning.     

Counting Integer Points in Parametric Polytopes Using Barvinok's Rational Functions

Many compiler optimization techniques depend on the ability to calculate the number of elements that satisfy certain conditions. If these conditions can be represented by linear constraints, then such problems are equivalent to counting the number of integer points in (possibly) parametric polytopes. It is well known that the enumerator of such a set can be represented by an explicit function consisting of a set of quasi-polynomials, each associated with a chamber in the parameter space. Previously, interpolation was used to obtain these quasi-polynomials, but this technique has several disadvantages. Its worst-case computation time for a single quasi-polynomial is exponential in the input size, even for fixed dimensions. The worst-case size of such a quasi-polynomial (measured in bits needed to represent the quasi-polynomial) is also exponential in the input size. Under certain conditions this technique even fails to produce a solution. Our main contribution is a novel method for calculating the required quasi-polynomials analytically. It extends an existing method, based on Barvinok's decomposition, for counting the number of integer points in a non-parametric polytope. Our technique always produces a solution and computes polynomially-sized enumerators in polynomial time (for fixed dimensions).