Exploration of the two‐photon excitation spectrum of fluorescent dyes at wavelengths below the range of the Ti:Sapphire laser

We have studied the wavelength dependence of the two‐photon excitation efficiency for a number of common UV excitable fluorescent dyes; the nuclear stains DAPI, Hoechst and SYTOX Green, chitin‐ and cellulose‐staining dye Calcofluor White and Alexa Fluor 350, in the visible and near‐infrared wavelength range (540–800 nm). For several of the dyes, we observe a substantial increase in the fluorescence emission intensity for shorter excitation wavelengths than the 680 nm which is the shortest wavelength usually available for two‐photon microscopy. We also find that although the rate of photo‐bleaching increases at shorter wavelengths, it is still possible to acquire many images with higher fluorescence intensity. This is particularly useful for applications where the aim is to image the structure, rather than monitoring changes in emission intensity over extended periods of time. We measure the excitation spectrum when the dyes are used to stain biological specimens to get a more accurate representation of the spectrum of the dye in a cell environment as compared to solution‐based measurements.     

The role of state policies and programs in buffering the effects of poverty on children's immunization receipt

OBJECTIVES: This study assessed the influence of public policies on the immunization status of 2-year old children in the United States. METHODS: Up-to-dateness for the primary immunization series was assessed in a national sample of 8100 children from the 1988 National Maternal and Infant Health Survey and its 1991 Longitudinal Follow-Up. RESULTS: Documented immunization rates of this sample were 33% for poor children and 44% for others. More widespread Medicated coverage was associated with greater likelihood of up-to-dateness among poor children. Up-to-dateness was more likely for poor children with public rather than private sources of routine pediatric care, but all children living in states where most immunizations were delivered in the public sector were less likely to be up to date. Poor children in state with partial vaccine replacement programs were less likely to be up to date than those in free-market purchase states. CONCLUSIONS: While state policies can enhance immunization delivery for poor children, heavy reliance on public sector immunization does not ensure timely receipt of vaccines. Public- and private-sector collaboration is necessary to protect children from vaccine-preventable diseases.     

Quantification of soluble solids in reconstituted açaí (Euterpe oleracea Mart.) pulp using near‐infrared spectroscopy

Açaí consumption is increasing worldwide because of the growing recognition of its nutritional and therapeutic properties. This product is classified based on its soluble solids content (SS), but the determination of SS in pulp is time consuming, tedious and not suitable for modern food processing plants. As near‐infrared (NIR) systems have been implemented to measure various quality attributes of food products, the objective of this study was to evaluate the feasibility of NIR diffuse reflectance spectroscopy to quantify the SS content of açaí pulp. Partial least squares (PLS) regression models were constructed to predict the SS. An optimum PLS model required one latent variable [principal component (PC)1 = 97%] with a root‐mean‐square error of calibration (RMSEC) of 1.06% for the calibration data set and the root‐mean‐square error of prediction (RMSEP) of 1.03% for internal cross‐validation. External validation using an independent data set showed good performance (RMSEP = 1.33% and Rp² = 0.82). NIR spectroscopy is a reliable method with which to determine SS in açaí pulp and thereby to classify açaí pulp according to established minimum quality standards.     

The material basis for reduced mechanical properties in oim mice bones

Osteogenesis imperfecta (OI), a heritable disease caused by molecular defects in type I collagen, is characterized by skeletal deformities and brittle bones. The heterozygous and homozygous oim mice (oim/+ and oim/oim) exhibit mild and severe OI phenotypes, respectively, serving as controlled animal models of this disease. In the current study, bone geometry, mechanics, and material properties of 1-year-old mice were evaluated to determine factors that influence the severity of phenotype in OI. The oim/oim mice exhibited significantly smaller body size, femur length, and moment of area compared with oim/+ and wild-type (+/+) controls. The oim/oim femur mechanical properties of failure torque and stiffness were 40% and 30%, respectively, of the +/+ values, and 53% and 36% of the oim/+ values. Collagen content was reduced by 20% in the oim/oim compared with +/+ bone and tended to be intermediate to these values for the oim/+. Mineral content was not significantly different between the oim/oim and +/+ bones. However, the oim/oim ash content was significantly reduced compared with that of the oim/+. Mineral carbonate content was reduced by 23% in the oim/oim bone compared with controls. Mineral crystallinity was reduced in the oim/oim and oim/+ bone compared with controls. Overall, for the majority of parameters examined (geometrical, mechanical, and material), the oim/+ values were intermediate to those of the oim/oim and +/+, a finding that parallels the phenotypes of the mice. This provides evidence that specific material properties, such as mineral crystallinity and collagen content, are indicative and possibly predictive of bone fragility in this mouse model, and by analogy in human OI.     

Case study feasibility analysis of renewable energy supply options for small to medium-sized tourist accommodations

This paper outlines a feasibility analysis of renewable energy supply (RES) for small to medium-scale tourist operations (less than 100 beds) dependent on stand-alone supplies. The analysis utilised the power load data from three accommodation case studies that had RES/hybrids already installed. The accommodation sites, chosen from diverse locations within Australia, varied in both climatic and geographic characteristics. The assessment criteria for the analysis were net present cost (NPC), renewable factor (RF) and payback time. The specific operational characteristics of the tourism accommodation sector, such as 24-h operation, comfort provision and low tolerance for failure, necessitates a separate assessment of RES viability for this sector, rather than relying on similar assessments from other commercial and domestic sectors, which may not be representative. This study utilised RES assessment software, HOMER (National Renewable Energy Laboratory, US) in order to compare the present RES/hybrid configuration to diesel generator-only (genset-only), RES-only and optimised RES/hybrid configurations. Analysis of both actual data and modeling results demonstrated that RES can adequately and reliably meet the power demand for stand-alone small to medium-scale tourist accommodations. Optimisation, achieved by further addition of RES to the existing configurations, reduced NPC in the majority of cases, with the added benefit of increased RF. Furthermore, NPC for these optimised RES/hybrid configurations were comparable to the optimised genset-only configurations. Modeling of conversions to RES-only configurations demonstrated this option as uneconomical unless existing RF was already high. Results indicated that wind energy conversion systems (WECS), rather than photovoltaics, were the most economical RES for sampled hybrid systems. For example, the payback time of the WECS/hybrids was approximately 3–4 years compared to PV/hybrids at 6–7 years. Hydrogen fuel cells and storage systems, whilst technically feasible, were not economically viable for the case studies due to the present high cost of components, especially compared to gensets. Modeling future potential increase in diesel fuel prices and implementation of carbon taxes shows a significant increase in NPC for genset-only configurations compared to RES/hybrid configurations in the sample. Carbon taxes of $50/ton increases NPC by 10% for genset-only systems but increases NPC less than half that amount for RES/hybrid systems. The data and subsequent modeling demonstrate that RES is both technically feasible and economically viable compared to diesel energy supply, for the small to medium-scale tourist operations sampled, dependent on stand-alone power supplies.