Encapsulation of Lead in Rice Phytoliths as a Possible Pollutant Source in Paddy Soils

Due to its serious health risks, lead (Pb) in rice, specifically its uptake, translocation, and accumulation mechanisms and its toxic effects have been studied intensively in recent years. However, it remains unclear about the role of phytolith, a siliceous structure in rice plants, in the storage and release kinetics of Pb in rice. This study aims at elucidating a possible encapsulation of Pb in the phytolith structure (phytPb), and identifying whether or not phytPb provides a source of Pb in soil, when returned to the field with the rice straw or in a related processed product such as ash from on-site burning. To date there has not been any specific work targeted at the determination of phytolith-associated heavy metals in general and phytPb in particular, and therefore this possible source of Pb in soils may have been overlooked. Phytoliths were included in a study of rice paddy soil and rice straw to demonstrate accumulation of phytolith and its associated phytPb in agricultural soils of the Red River Delta (Vietnam). The total content of Pb in rice straw samples was found to be up to 118mgkg−1,andthisPbsinkcanbecycledtoserveasanewPbsourceinsoils.ThefateofPbinricestraw might be directly related to open burning activity (a common practice in the Red River Delta), in which volatilization or sub-compartmentation in slagged phytolith appeared as controlled factors. This is supported by the findings from batch experiments for rice straw ash samples, in which release of Pb was low and a portion of Pb in rice straw were found to associate with phytolith structural organic matter. We also observed the presence of phytPbin aged phytolithfragmentswhichhadaccumulatedinthepaddyfieldsoil.HoweverthisPbpoolwas relativelylow(from7.8to34kgha−1)relativetoothersoilPbfractions.AsthethermaltreatmentsofPb-tainted rice straw resulted in losses of Pb via volatilization, open-field burning practices for Pb-contaminated rice straw is suggested as an environmental ris

Suprachoroidal and Subretinal Injections of AAV Using Transscleral Microneedles for Retinal Gene Delivery in Nonhuman Primates.

Retinal gene therapy using adeno-associated viruses (AAVs) is constrained by the mode of viral vector delivery. Intravitreal AAV injections are impeded by the internal limiting membrane barrier, while subretinal injections require invasive surgery and produce a limited region of therapeutic effect. In this study, we introduce a novel mode of ocular gene delivery in rhesus macaques using transscleral microneedles to inject AAV8 into the subretinal or suprachoroidal space, a potential space between the choroid and scleral wall of the eye. Using in vivo imaging, we found that suprachoroidal AAV8 produces diffuse, peripheral expression in retinal pigment epithelial (RPE) cells, but it elicited local infiltration of inflammatory cells. Transscleral subretinal injection of AAV8 using microneedles leads to focal gene expression with transduction of RPE and photoreceptors, and minimal intraocular inflammation. In comparison, intravitreal AAV8 shows minimal transduction of retinal cells, but elicits greater systemic humoral immune responses. Our study introduces a novel mode of transscleral viral delivery that can be performed without vitreoretinal surgery, with focal or diffuse transgene expression patterns suitable for different applications. The decoupling of local and systemic immune responses reveals important insights into the immunological consequences of AAV delivery to different ocular compartments surrounding the blood-retinal barrier

Performance on Cognitive Broadcasting Networks Employing Fountain Codes and Maximal Ratio Transmission

The comprehensive performance of cognitive broadcasting networks employing Fountain codes (FC) and maximal ratio transmission (MRT) is investigated in the present paper. More precisely, the secondary transmitter (ST) employs Fountain code to effectively broadcast a common message such as a safety warning, security news, etc., to all secondary receivers (SRs) via underlay protocol of cognitive radio networks (CRNs). Different from works in the literature that are interested in studying the outage probability (OP), and the ergodic capacity of the CRNs. The present paper, on the other hand, focuses on the characteristics of the number of needed time slots to successfully deliver such a message. Particularly, we derive in closed-form expressions the cumulative distribution function (CDF), the probability mass function (PMF), and the average number of the required time slot to broadcast the message to all SRs. Additionally, we also provide the throughput of secondary networks (SNs). We point out the impact of some key parameters, i.e., the number of SRs and the number of transmit antennae at the secondary transmitter, on the performance of these considered metrics. Numerical results via the Monte-Carlo method are given to verify the accuracy of the derived framework as well as to highlight the influences of some essential parameters. Furthermore, we also compare the performance of the proposed networks with state-of-the-art and simulation results unveiling that the considered system consistently outperforms works in the literature

Photoluminescent, upconversion luminescent and nonlinear optical metal-organic frameworks: From fundamental photophysics to potential applications

Metal-organic frameworks (MOFs) are a class of porous materials prepared by the self-assembly of metal ions or clusters with organic ligands. The unique characteristics of MOFs, including structural tunability, high surface areas, low densities and tailored pore surface functionalization, have made them leading contenders as high-performance porous materials, alongside the established zeolites and activated carbons. Consequently, the permanent porosity of MOFs has been extensively exploited for gas capture and separation and catalysis. In recent years, the field has been expanded towards new applications and many studies of MOFs are venturing into unexplored avenues. A large number of studies have been focused on photoluminescent, upconversion luminescent, and nonlinear optical MOFs for applications in areas such as white-light emission, bioimaging, sensing, and photocatalysis. Within the first half of this tutorial review, we present the fundamental principles of luminescence, including detailed scientific discussions on the luminescence origin of different materials such as organic dyes, transition metal complexes, quantum dots, and lanthanide compounds. Principles and important parameters for the applications of luminescent MOFs are introduced, followed by a summary of recent interesting publications for each application. In the second half, we introduce nonlinear optical effects including second harmonic generation and two-photon absorption, and upconversion of luminescence, followed by detailed examples of MOFs that exhibit these phenomena. Finally, insights about the remaining challenges and future directions are discussed. (C) 2018 Elsevier B.V. All rights reserved

The epidemiology and aetiology of diarrhoeal disease in infancy in southern Vietnam: a birth cohort study.

OBJECTIVES: Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children, however longitudinal community-based data on burden and aetiology are limited. The findings from a large, prospective cohort study of diarrhoeal disease in infants in southern Vietnam are presented herein. METHODS: Infants were enrolled at birth in urban Ho Chi Minh City and a semi-rural district in southern Vietnam, and followed for 12 months (n=6706). Diarrhoeal illness episodes were identified through clinic-based passive surveillance, hospital admissions, and self-reports. RESULTS: The minimum incidence of diarrhoeal illness in the first year of life was 271/1000 infant-years of observation for the whole cohort. Rotavirus was the most commonly detected pathogen (50% of positive samples), followed by norovirus (24%), Campylobacter (20%), Salmonella (18%), and Shigella (16%). Repeat infections were identified in 9% of infants infected with rotavirus, norovirus, Shigella, or Campylobacter, and 13% of those with Salmonella infections. CONCLUSIONS: The minimum incidence of diarrhoeal disease in infants in both urban and semi-rural settings in southern Vietnam was quantified prospectively. A large proportion of laboratory-diagnosed disease was caused by rotavirus and norovirus. These data highlight the unmet need for a rotavirus vaccine in Vietnam and provide evidence of the previously unrecognized burden of norovirus in infants