Hybrids of gold nanoparticles and oligo(p-phenyleneethynylene)s end-functionalized with alkynylruthenium groups: Outstanding two-photon absorption in the second biological window

Oligo(p-phenyleneethynylene)s (OPEs) end-capped with (alkynyl)bis(diphosphine)ruthenium and thiol/thiolate groups stabilize ca. 2 nm diameter gold nanoparticles (AuNPs). The morphology, elemental composition and stability of the resultant organometallic OPE/AuNP hybrid materials have been defined using a combination of molecular- and nano-material chacterization techniques. The hybrids display long-term stability in solution (more than a month), good solubility in organic solvents, reversible ruthenium-centered oxidation, and transparency beyond 800 nm, and possess very strong nonlinear absorption activity at the first biological window, and unprecedented two-photon absorption activity in the second biological window (σ₂ up to 38,000 GM at 1,050 nm).

     

An evaluative study of TRMM precipitation estimates over multi-day scales in a semi-arid region,Iran

Data from the Tropical Rainfall Measuring Mission (TRMM) rainfall estimations have been evaluated at different time scales in the previous research, in particular, sub-daily, monthly, seasonally and annually. However, in arid and semi-arid regions water balance may be reached several days after a rainfall event. Hence, it becomes of crucial importance to investigate sub-monthly time periods (i.e. multi-day periods). For this reason, TRMM precipitation data version 3B42 (3B42) were evaluated and calibrated for 1, 2, 3, 5, 7, 10, 15, 20 days and monthly time scales using rain gauges data in Fars province, Islamic Republic of Iran, 1 January 2000 to 31 December 2014. Pearson’s correlation coefficient (r), Root Mean Square Error (RMSE), Normalized Root Mean Square Error (NRMSE), Mean Bias (MB), Prediction of Detection (POD), False Alarm Ratio (FAR) and Critical Success Index (CSI) were used for the purpose of evaluation. The results showed that with a logarithmic trend, r, NRMSE, and FAR values decreased while RMSE, CSI, and POD values increased with increasing time scales. Moreover, the spatial average MB was almost constant for various time scales, although the percentage of grid cells with over-estimated rainfall increased from 1 day to 1 month. By fitting logarithmic functions over the values of r, RMSE, NRMSE, POD, FAR, and CSI at 1, 10 days, and monthly time scales, the corresponding values of these measures were predicted for other time scales with the relative error (NRMSE) of less than 0.1, which indicates the accurate performance of these functions. Through linear regression analysis, the slope (M) and interception (B) of the equations for calibrating 3B42 precipitation estimates at various time scales were obtained. Furthermore, the results showed that the obtained values of M and B in 1, 10 days, and monthly time scales can be estimated with a high accuracy at 2, 3, 5, 7, 15, and 20 days.     

A discussion paper on challenges and limitations to water reuse and hygiene in the food industry

Drinking water is becoming a scarce resource in many areas and both use of water and wastewater outlet are of major ecological and economical importance in many countries. Consumption and discharge may be considerably minimized by means of water reuse. The food industry has a large consumption of water, but until now very limited reuse has taken place due to legislations constraints and hygienic concerns. Legal space for use of water of qualities other than drinking water has been opened with the current legislation. This will, however, in many cases require careful analyses of individual cases based on a thorough understanding of the hazards involved in order to avoid compromising the safety of the food product and thereby the health of consumers. Implementation of water reuse practices in the food industry presents a great challenge for both companies and public health authorities regarding knowledge, technical expertise and documentation. Regulatory, technological, monitoring, verification and ethical aspects associated with microbiologically safe reuse of water in the food industry are discussed and some examples of the challenges ahead and possible approaches are given.