Screening the Incorporation of Amino Acids into an Inorganic Crystalline Host: the Case of Calcite

Organisms have the ability to produce structures with superior characteristics as in the course of biomineralization. One of the most intriguing characteristics of biominerals is the existence of intracrystalline macromolecules. Despite several studies over the last two decades and efforts to mimic the incoporation of macromolecules synthetically, a fundamental understanding of the mechanism of incorporation is as yet lacking. For example, which of the common 20 amino acids are really responsible for the interaction with the mineral phase? Here a reductionist approach, based on high‐resolution synchrotron powder diffraction and analytical chemistry, is utilized to screen all of these amino acids in terms of their incorporation into calcite. We showed that the important factors are amino‐acid charge, size, rigidity and the relative pKa of the carboxyl and amino functional groups. It is also demonstrated that cysteine, surprisingly, interacts very strongly with the mineral phase and therefore, like acidic amino acids, becomes richly incorporated. The insights gained from this study shed new light on the incorporation of organic molecules into an inorganic host in general, and in particular on the biomineralization process.     

Range gated active night vision system for automobiles

Night vision for automobiles is an emerging safety feature that is being introduced for automotive safety. We develop what we believe is an innovative new night vision system using gated imaging principles. The concept of gated imaging is described and its basic advantages, including the backscatter reduction mechanism for improved vision through fog, rain, and snow. Evaluation of performance is presented by analyzing bar pattern modulation and comparing Johnson chart predictions.     

Risk and preventive factors for fatalities in All-terrain Vehicle Accidents in New Zealand

All-Terrain Vehicles (ATVs) have been used in agriculture for a few decades now. Yet despite their invaluable contribution to the productivity of the agricultural industry they are associated with a large number of accidents, many of which result in a severe or fatal outcome. The main objective of this study was to identify the risk factors for ATV-related fatal injuries in order to support the design of effective interventions. Using data held by the Department of Labour, the current study analysed 355 cases of serious harm accidents associated with ATVs including 45 fatalities. The findings suggest that injuries are more likely to occur when accidents involve any of the following: children under the age of 10; four-wheel drive ATVs; driving downhill; driving on a sealed road; driving backwards; or if the ATV rolls sideways. A fatal outcome is more likely to occur when ATV accidents end up with the vehicle rolling over and pinning the driver underneath. Fatalities were also associated with injuries to the head, neck and chest. Being employed; and/or having formal training; and/or having brakes and tyres well maintained on the ATV; and/or having no fluid load on the ATV reduced the risk for fatality. Since the likelihood of a fatal outcome was found to be related to human behaviour and ATV rollover, it is suggested that interventions should mainly address these two issues.     

New maximum likelihood motion estimation schemes for noisy ultrasound images

When performing block-matching based motion estimation with the ML estimator, one would try to match blocks from the two images, within a predefined search area. The estimated motion vector is that which maximizes a likelihood function, formulated according to the image formation model. Two new maximum likelihood motion estimation schemes for ultrasound images are presented. The new likelihood functions are based on the assumption that both images are contaminated by a Rayleigh distributed multiplicative noise. The new approach enables motion estimation in cases where a noiseless reference image is not available. Experimental results show a motion estimation improvement with regards to other known ML estimation methods.     

Identification of an NADH-dependent 5-hydroxymethylfurfural-reducing alcohol dehydrogenase in Saccharomyces cerevisiae

We report on the identification and characterization of a mutated alcohol dehydrogenase 1 from the industrial Saccharomyces cerevisiae strain TMB3000 that mediates the NADH-dependent reduction of 5-hydroxymethylfurfural (HMF) to 2,5-bis-hydroxymethylfuran. The co-factor preference distinguished this alcohol dehydrogenase from the previously reported NADPH-dependent S. cerevisiae HMF alcohol dehydrogenase Adh6. The amino acid sequence revealed three novel mutations (S109P, L116S and Y294C) that were all predicted at the vicinity of the substrate binding site, which could explain the unusual substrate specificity. Increased biomass production and HMF conversion rate were achieved in a CEN.PK S. cerevisiae strain overexpressing the mutated ADH1 gene.     

Resource allocation in stochastic,finite-capacity,multi-project systems through the cross entropy methodology

This paper addresses the problem of resource allocation in a finite-capacity, stochastic (random) and dynamic multi-project system. The system is modeled as a queuing network that is controlled by limiting the number of concurrent projects. We propose a Cross Entropy (CE) based approach to determine near-optimal resource allocations to the entities that execute the projects. The performance of the suggested approach is demonstrated through numerical experiments and compared to that of a heuristic, rough-cut based method.     

Neocartilage integration in temporomandibular joint discs: physical and enzymatic methods

Integration of engineered musculoskeletal tissues with adjacent native tissues presents a significant challenge to the field. Specifically, the avascularity and low cellularity of cartilage elicit the need for additional efforts in improving integration of neocartilage within native cartilage. Self-assembled neocartilage holds significant potential in replacing degenerated cartilage, though its stabilization and integration in native cartilage require further efforts. Physical and enzymatic stabilization methods were investigated in an in vitro model for temporomandibular joint (TMJ) disc degeneration. First, in phase 1, suture, glue and press-fit constructs were compared in TMJ disc intermediate zone defects. In phase 1, suturing enhanced interfacial shear stiffness and strength immediately; after four weeks, a 15-fold increase in stiffness and a ninefold increase in strength persisted over press-fit. Neither suture nor glue significantly altered neocartilage properties. In phase 2, the effects of the enzymatic stabilization regimen composed of lysyl oxidase, CuSO₄ and hydroxylysine were investigated. A full factorial design was employed, carrying forward the best physical method from phase 1, suturing. Enzymatic stabilization significantly increased interfacial shear stiffness after eight weeks. Combined enzymatic stabilization and suturing led to a fourfold increase in shear stiffness and threefold increase in strength over press-fit. Histological analysis confirmed the presence of a collagen-rich interface. Enzymatic treatment additionally enhanced neocartilage mechanical properties, yielding a tensile modulus over 6 MPa and compressive instantaneous modulus over 1200 kPa at eight weeks. Suturing enhances stabilization of neocartilage, and enzymatic treatment enhances functional properties and integration of neocartilage in the TMJ disc. Methods developed here are applicable to other orthopaedic soft tissues, including knee meniscus and hyaline articular cartilage.     

Distributed approximation of cellular coverage

We consider the following model of cellular networks. Each base station has a given finite capacity, and each client has some demand and profit. A client can be covered by a specific subset of the base stations, and its profit is obtained only if its demand is provided in full. The goal is to assign clients to base stations, so that the overall profit is maximized subject to base station capacity constraints.