Extrahepatic metabolism of 4-methylumbelliferone and lidocaine in the anhepatic rabbit

OBJECTIVE: The initially well-fixed implants of total hip replacement (THR) are in the long-term subject to aseptic loosening. Many cytokines can contribute to osteolysis due to osteoclast recruitment and/or activation. However, in this respect tumor necrosis factor-alpha (TNF-alpha) plays a pivotal role, because it upregulates interleukin-1 and 6 and granulocyte-macrophage colony stimulating factor. The aim of this study was to assess the eventual presence, cellular localization and extent of expression of TNF-alpha in the synovial-like membrane at the implant or at the cement to bone interface compared to control synovial membrane. METHODS: Twenty samples from the synovial-like membrane of the periprosthetic tissues were compared to control samples. TNF-alpha containing cells were visualized using an avidin-biotin-peroxidase complex (ABC) method and analyzed by light microscopy, double labelling and image analysis. RESULTS: TNF-alpha was found in the periprosthetic tissues in fibroblasts and vascular endothelial cells, but mainly in the macrophages was it found to coincide with areas containing implant-derived debris. TNF-alpha containing cells were more numerous in the synovial-like membrane in the interface tissue from the proximal stem area (2816 +/- 318 cells) than in the control synovial membrane (565 +/- 93 cells, p < 0.01). Interestingly, similarly high TNF-alpha expression (3452 +/- 582 cells) was also seen in the synovial-like membrane of the pseudocapsule. CONCLUSION: These findings suggest that the foreign body-type host reaction caused by THR is characterized by the high expression of TNF-alpha. Because such expression occurred in the interface tissue between the implant and surrounding bone, TNF-alpha, due to its pivotal direct and indirect role in the activation and recruitment of osteoclasts, may contribute to periprosthetic osteolysis and to the loosening of THR.     

A connection between the Cantor–Bendixson derivative and the well-founded semantics of finite logic programs

Results of Schlipf (J Comput Syst Sci 51:64?C86, 1995) and Fitting (Theor Comput Sci 278:25?C51, 2001) show that the well-founded semantics of a finite predicate logic program can be quite complex. In this paper, we show that there is a close connection between the construction of the perfect kernel of a $\Pi^0_1$ class via the iteration of the Cantor?CBendixson derivative through the ordinals and the construction of the well-founded semantics for finite predicate logic programs via Van Gelder??s alternating fixpoint construction. This connection allows us to transfer known complexity results for the perfect kernel of $\Pi^0_1$ classes to give new complexity results for various questions about the well-founded semantics ${\mathit{wfs}}(P)$ of a finite predicate logic program P.     

X-ray microtomography (microCT) of the progression of sulfate attack of cement paste

High-resolution X-ray computed tomography (i.e., microCT or microtomography) was used to study the sulfate attack of cylinders of Type I cement paste cast with water-cement (w/c) ratios of 0.45, 0.50 and 0.60. Damage levels in samples exposed to a Na₂SO₄ solution with 10,000 ppm sulfate ion concentration were qualitatively rated from 0 (no damage) to 4 (extreme damage) based upon visual examination of the samples' exteriors and microtomography of the samples' interiors. The greater the w/c ratio, the more rapid the onset of sulfate damage. The corners of the cylinders appeared to be particularly susceptible to spalling, and damage may have continued into the cement paste by formation of subsurface cracks.     

Consistency properties and set based logic programming

Blair et al. (2001) developed an extension of logic programming called set based logic programming. In the theory of set based logic programming the atoms represent subsets of a fixed universe X and one is allowed to compose the one-step consequence operator with a monotonic idempotent operator O so as to ensure that the analogue of stable models in the theory are always closed under O. Marek et al. (1992, Ann Pure Appl Logic 96:231–276 1999) developed a generalization of Reiter’s normal default theories that can be applied to both default theories and logic programs which is based on an underlying consistency property. In this paper, we show how to extend the normal logic programming paradigm of Marek, Nerode, and Remmel to set based logic programming. We also show how one can obtain a new semantics for set based logic programming based on a consistency property.     

Non-Gaussian Model for Ringing Phenomena in Offshore Structures

Significant interest has been shown in identifying the nonlinear mechanisms that induce a ringing type response in offshore structural systems. This high frequency transient type response has been observed in offshore systems, particularly in tension leg platforms (TLPs). Given the implications of this behavior on the fatigue life of TLP tendons, it is essential that ringing be considered in the overall response evaluation. This study presents two non-Gaussian probabilistic models of nonlinear viscous hydrodynamic wave forces that induce ringing. The response of a single-degree-of-freedom system exposed to these non-Gaussian wave force models is then evaluated using analytical and numerical studies based on the It? differentiation rule and the Monte Carlo simulation procedure, respectively. The results demonstrate that the proposed models induce ringing type response in a simplified structure. This study provides a probabilistic framework for modeling ringing type phenomenon which will serve as a building block for more refined hydrodynamic load models.     

Creep of UHPC in tension and compression: Effect of thermal treatment

Steel fiber-reinforced ultra-high performance concrete (UHPC) is of increasing interest for use in precast prestressed concrete highway bridge girders due to its superior durability and the potential for reducing or eliminating shear reinforcement, due to the presence of steel fibers. However, the contributions of creep, and especially tensile creep, to long-term performance must be better understood to develop appropriate design specifications. Due to practical considerations, it is also of interest to investigate the influence of varying thermal treatment, including temperatures lower than those recommended by the manufacturer (i.e. 90 °C), on the creep of UHPC. In this 1-year study, the effects of three different thermal treatment regimes on tensile and compressive creep performance of UHPC are examined, with complementary characterization by nanoindentation and scanning electron microscopy. Results show that UHPC creeps phenomenologically differently in tension and compression. Both thermal treatments examined resulted in similar tensile creep behavior, suggesting that a lower temperature applied over a longer period could effectively cure UHPC. For the non-thermally cured UHPC, a 10 μm wide region observed at the fiber/matrix interface was characterized by reductions in elastic modulus as well as greater porosity and microcracking than the bulk paste. It is suggested that the quality of the fiber/matrix interface is a major contributor to the measured increased creep of non-thermally treated UHPC as compared to UHPC treated at 60 °C or 90 °C.     

Water Efficiency and the Professional Plumbing Sector: How Capacity and Capability Influence Knowledge Acquisition and Innovation

Professional plumbers play an essential role in the implementation of water efficiency. If North America is to achieve high water efficiency standards and more ambitious plumbing codes, plumbers will need to be actively included in the water efficiency discussion. Repositioning the industry will required a cultural shift because the plumbing community has been mostly ignored in discussions of the larger environmental agenda and priorities. This repositioning will require substantial rethinking and retraining. New knowledge will need to be transmitted about emerging water efficient technologies, public policies and practices, as well as the rationale for use in residential and Industrial, Commercial, and Institutional (ICI) sectors. The GreenPlumbers Program (GPP) initiated this knowledge transfer process. Originating in Australia and expanded to the United States, the GPP is a national training and accreditation program for professional plumbers. Their focus has been on upgrading skills and awareness of water efficiency, conservation, and the professional plumbers’ roles in the contemporary environmental context. In this paper we report on the efficacy of the GPP’s curriculum and the process of transferring explicit water efficiency knowledge. Semi-structured interviews and a survey were used to gather the data. We considered how the program participants incorporated the GPP curriculum into their ‘day-to-day’ practices and operations post-certification. We also investigated participants’ motivating factors and cross-referenced these findings to their overall assessment of the program. Recommendations focus on how the GPP can best influence and contribute to a more comprehensive water efficiency agenda.     

Inhibitors of the salicylate synthase (MbtI) from Mycobacterium tuberculosis discovered by high-throughput screening

A simple steady‐state kinetic high‐throughput assay was developed for the salicylate synthase MbtI from Mycobacterium tuberculosis, which catalyzes the first committed step of mycobactin biosynthesis. The mycobactins are small‐molecule iron chelators produced by M. tuberculosis, and their biosynthesis has been identified as a promising target for the development of new antitubercular agents. The assay was miniaturized to a 384‐well plate format and high‐throughput screening was performed at the National Screening Laboratory for the Regional Centers of Excellence in Biodefense and Emerging Infectious Diseases (NSRB). Three classes of compounds were identified comprising the benzisothiazolones (class I), diarylsulfones (class II), and benzimidazole‐2‐thiones (class III). Each of these compound series was further pursued to investigate their biochemical mechanism and structure–activity relationships. Benzimidazole‐2‐thione 4 emerged as the most promising inhibitor owing to its potent reversible inhibition.     

Characterization of ultrasonic Rayleigh surface waves in asphaltic concrete

This research examines the application of ultrasonic Rayleigh surface waves to the non-destructive evaluation (NDE) of asphaltic concrete in the frequency range 40–100 kHz. Two ultrasonic parameters, the phase velocity and amplitude attenuation, are considered to be sensitive to local compositional and structural variations and are measured. A wedge technique is used to generate Rayleigh surface waves in an asphaltic concrete beam with uniformly distributed aggregate, and this technique is shown to be effective in launching Rayleigh waves in this highly viscoelastic (absorptive) and heterogeneous medium. Three different ultrasonic detection setups using contact and non-contact transducers as receivers are examined and their results are compared. The experimental results show that the wedge generation technique along with an air-coupled receiving transducer with a finite-size aperture is the most reliable for characterizing Rayleigh waves in asphaltic concrete. It is also experimentally demonstrated that the proposed setup may be used to detect aggregate segregation in asphaltic concrete.