Water Quality Sensing and Spatio-Temporal Monitoring Structure with Autocorrelation Kernel Methods.

Pollution on water resources is usually analyzed with monitoring campaigns, which consist of programmed sampling, measurement, and recording of the most representative water quality parameters. These campaign measurements yields a non-uniform spatio-temporal sampled data structure to characterize complex dynamics phenomena. In this work, we propose an enhanced statistical interpolation method to provide water quality managers with statistically interpolated representations of spatial-temporal dynamics. Specifically, our proposal makes efficient use of the a priori available information of the quality parameter measurements through Support Vector Regression (SVR) based on Mercer's kernels. The methods are benchmarked against previously proposed methods in three segments of the Machángara River and one segment of the San Pedro River in Ecuador, and their different dynamics are shown by statistically interpolated spatial-temporal maps. The best interpolation performance in terms of mean absolute error was the SVR with Mercer's kernel given by either the Mahalanobis spatial-temporal covariance matrix or by the bivariate estimated autocorrelation function. In particular, the autocorrelation kernel provides with significant improvement of the estimation quality, consistently for all the six water quality variables, which points out the relevance of including a priori knowledge of the problem.

Honeybee pollen assisted biosynthesis of nanogold and its application as catalyst in reduction of 4-nitrophenol.

Nowadays, the exploration of natural materials for the production of nanoparticles is of special interest due to its ecofriendly nature. In this paper, we presented the biosynthesis of gold nanoparticles (AuNPs) in a green route by using water extract of pollen from Andean honeybees. Furthermore, AuNPs have been characterized by various techniques and tested for the catalytic reduction of 4-nitrophenol (4-NP). The biosynthesized AuNPs were analyzed using UV-vis spectroscopy, Transmission electron microscopy (TEM), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectroscopy to confirm their optical properties, stability, surface morphology, and purity. The synthesized AuNPs proved to be well dispersed, spherical, and triangular in shape, with particle sizes ranging from 7 to 42 nm having λmax at 530 nm. Moreover, FTIR suggests the capping of AuNPs with pollen constituents and XRD confirms the crystalline structure of AuNPs. Additionally, prepared AuNPs were demonstrated to be effective in reducing organic pollutant 4-NP to 4-aminophenol (k = 59.17898 × 10-3 min-1, R2 = 0.994). All of these studies have emphasized that AuNPs production can be scale up by using naturally available pollen grains and open up a new perspective for beekeepers.

Synthesis of Iron, Zinc, and Manganese Nanofertilizers, Using Andean Blueberry Extract, and Their Effect in the Growth of Cabbage and Lupin Plants.

The predominant aim of the current study was to synthesize the nanofertilizer nanoparticles ZnO_MnO-NPs and FeO_ZnO-NPs using Andean blueberry extract and determine the effect of NPs in the growth promotion of cabbage (Brassica oleracea var. capitata) and Andean lupin (Lupinus mutabilis sweet) crops. The nanoparticles were analyzed by visible spectrophotometry, size distribution (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Solutions of nanoparticle concentrations were applied to cabbage, with solutions of 270 and 540 ppm of ZnO_MnO-NPs and 270 and 540 ppm of FeO_ZnO-NPs applied to Andean lupin. Zinc was used in both plants to take advantage of its beneficial properties for plant growth. Foliar NPs sprays were applied at the phenological stage of vegetative growth of the cabbage or Andean lupin plants grown under greenhouse conditions. The diameter of the NPs was 9.5 nm for ZnO, 7.8 nm for FeO, and 10.5 nm for MnO, which facilitate the adsorption of NPs by the stomata of plants. In Andean lupin, treatment with 270 ppm of iron and zinc indicated increases of 6% in height, 19% in root size, 3.5% in chlorophyll content index, and 300% in leaf area, while treatment with 540 ppm of iron and zinc yielded no apparent increases in any variable. In cabbage, the ZnO_MnO-NPs indicate, at a concentration of 270 ppm, increases of 10.3% in root size, 55.1% in dry biomass, 7.1% in chlorophyll content, and 25.6% in leaf area. Cabbage plants treated at a concentration of 540 ppm produced increases of 1.3% in root size and 1.8% in chlorophyll content, compared to the control, which was sprayed with distilled water. Therefore, the spray application of nanofertilizers at 270 ppm indicated an important improvement in both plants' growth.

Bioremediation on a chip: A portable microfluidic device for efficient screening of bacterial biofilm with polycyclic aromatic hydrocarbon removal capacity.

Polycyclic aromatic hydrocarbons (PAHs) are pollutants of critical environmental and public health concern and their elimination from contaminated sites is significant for the environment. Biodegradation studies have demonstrated the ability of bacteria in biofilm conformation to enhance the biodegradation of pollutants. In this study, we used our newly developed microfluidic platform to explore biofilm development, properties, and applications of fluid flow, as a new technique for screening PAHs-degrading biofilms. The optimization and evaluation of the flow condition in the microchannels were performed through computational fluid dynamics (CFD). The formation of biofilms by PAHs-degrading bacteria Pseudomonas sp. P26 and Gordonia sp. H19, as pure cultures and co-culture, was obtained in the developed microchips. The removal efficiencies of acenaphthene, fluoranthene and pyrene were determined by HPLC. All the biofilms formed in the microchips removed all tested PAHs, with the higher removal percentages observed with the Pseudomonas sp. P26 biofilm (57.4% of acenaphthene, 40.9% of fluoranthene, and 28.9% of pyrene). Pseudomonas sp. P26 biofilm removed these compounds more efficiently than planktonic cultures. This work proved that the conformation of biofilms enhances the removal rate. It also provided a new tool to rapid and low-cost screen for effective pollutant-degrading biofilms.

Preparation of Fe oxide nanoparticles for environmental applications: arsenic removal.

The objective of this study is to examine the adsorption-desorption behavior of a magnetically active hybrid sorbent (MAHS) material, prepared by dispersing colloid-like hydrated iron oxide particles in the outer periphery of a macroporous ion-exchange resin (Amberlite XAD-2). The experimental results show that the new sorbent material can simultaneously remove arsenic (V) and a chlorinated organic compound (2,6-dichlorophenol [2,6-DCP]) from aqueous solutions at around neutral pH. The recovery of arsenic and 2,6-DCP from MAHS was conducted using a regenerant containing 50% (v/v) CH3OH + 3% (w/v) NaOH. In less than 10 bed volumes of regenerant, more than 90% of As(V) and 2,6-DCP were recovered.

Andean Sacha Inchi (Plukenetia Volubilis L.) Leaf-Mediated Synthesis of Cu2O Nanoparticles: A Low-Cost Approach.

In this work, Andean sacha inchi (Plukenetia volubilis L.) leaves were used to prepare monodispersed cuprous oxide (Cu2O) nanoparticles under heating. Visual color changes and UV-visible spectroscopy of colloidal nanoparticles showed λmax at 255 nm, revealing the formation of copper oxide nanoparticles. Transmission electron microscopy and dynamic light scattering analysis indicated that the prepared nanoparticles were spherical with an average size of 6-10 nm. The semi-crystalline nature and Cu2O phase of as-prepared nanoparticles were examined by X-ray diffraction. Fourier-transform infrared spectroscopy confirmed the presence of polyphenols, alkaloids and sugar in the sacha inchi leaf, allowing the formation of Cu2O nanoparticles from Cu2+. Additionally, as-synthesized Cu2O nanoparticles exhibited good photocatalytic degradation activity against methylene blue (>78%, 150 min) with rate constant 0.0219106 min-1. The results suggested that the adopted method is low-cost, simple, ecofriendly and highly selective for the synthesis of small Cu2O nanoparticles and may be used as a nanocatalyst in the future in the efficient treatment of organic pollutants in water.

Cost-effective fabrication of photopolymer molds with multi-level microstructures for PDMS microfluidic device manufacture.

This paper describes a methodology of photopolymer mold fabrication with multi-level microstructures for polydimethylsiloxane (PDMS) microfluidic device manufacture. Multi-level microstructures can be performed by varying UVA exposure time and channel width. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and profilometry techniques have been employed to characterize the molds. Multiple molds with multi-level microstructures can be formed in a unique piece. Overall height/depth of the structures reaches up to 677 µm and a minimum of 21 µm. The method provides several advantages such as reduction of fabrication time, multiple structures with diverse topologies, a great variety of depth and height in a single mold and low cost of fabrication. The effectiveness of multi-level microstructure fabrication was evaluated by constructing PDMS microfluidic devices for cell culture and proliferation.

Hybrid microchannel-solid state micropore device for fast and optical cell detection.

This paper presents a methodology for cell detection and counting using a device that combines PDMS (polydimethylsiloxane) microfluidic multilayer channels with a single solid state micropore. Optimal conditions of solid-state micropore fabrication from crystalline silicon wafers are presented. Micropores of varying size can be obtained by directly etching using an etchant agent concentration of 50 wt% KOH, at varying temperatures (40, 60, 80 °C) and voltages (100, 500, 1000 mV). Scanning Electron Microscopy (SEM), and profilometry techniques have been used for the micropore characterization. In order to find optimal conditions for cell detection a COMSOL Multiphysics simulation was performed. Pressure drop, shear stress, fluid viscosities and flow rates parameters were evaluated. The potential viability of the device for cell detection and counting, avoiding cellular damage, is demonstrated.

Differential biological activity of two extracts of ripe fruits of Carica candamarcensis Hook on human neutrophils / Actividad biologica diferencial de dos extractos de frutos maduros de Carica candamarcensis Hook en neutrófilos humanos

We evaluated the effect of the total macerate (TM) and seed oil (SO) of mature Carica candamarcensis fruits, on the release of Matrix metalloproteinase 9 (MMP9) and the phosphorylation of MAPK in neutrophils. The antioxidant capacity of these extracts was evaluated by ABTS assay. Neutrophils stimulated with different dilutions of TM or SO were analyzed for cytotoxicity, MMP9 release, and MAPK phosphorylation, using trypan blue exclusion assays, zymography, and immunoblotting, respectively. Both extracts show antioxidant activity, being higher in TM; none presented cytotoxic effect. The 5% and 2.5% dilutions of TM significantly reduced MMP9 release, and all decreased MAPK phosphorylation. SO significantly increased the release o f MMP9 and MAPK phosphorylation, the effect being greater when they were prestimulated with lipopolysaccharide.TM may have anti - inflammatory potential, while SO could have a priming effect that needs to be confirmed

Evaluamos el efecto del macerado total (MT) y aceite de semillas (AV) de frutos maduros de Carica candamarcensis , en la liberación de Matriz metaloproteinasa 9 (MMP9) y la fosfor ilación de MAPK en neutrófilos. La capacidad antioxidante de estos extractos se evaluó por ensayo ABTS. En neutrófilos estimulados con diferentes diluciones de MT o AV se analizó la citotoxicidad, liberación de MMP9 y fosforilación de MAPK, mediante ensayo s de exclusión con azul de tripano, zimografía e inmunotransferencia, respectivamente. Ambos extractos muestran actividad antioxidante, siendo mayor en MT; ninguno presentó efecto citotóxico. Las diluciones 5% y 2,5% de MT redujeron significativamente la l iberación de MMP9, y todas disminuyeron la fosforilación de MAPK. El AV incrementó significativamente la liberación de MMP9 y la fosforilación de MAPK, el efecto fue mayor cuando se preestimularon con lipopolisacárido. El MT puede tener potencial antiinfla matorio, mientras que el AV podría tener un efecto "priming" que necesita ser corroborado.

Green synthesis of silver nanoparticles using Andean blackberry fruit extract.

Green synthesis of nanoparticles using various plant materials opens a new scope for the phytochemist and discourages the use of toxic chemicals. In this article, we report an eco-friendly and low-cost method for the synthesis of silver nanoparticles (AgNPs) using Andean blackberry fruit extracts as both a reducing and capping agent. The green synthesized AgNPs were characterized by various analytical instruments like UV-visible, transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The formation of AgNPs was analyzed by UV-vis spectroscopy at λmax = 435 nm. TEM analysis of AgNPs showed the formation of a crystalline, spherical shape and 12-50 nm size, whereas XRD peaks at 38.04°, 44.06°, 64.34° and 77.17° confirmed the crystalline nature of AgNPs. FTIR analysis was done to identify the functional groups responsible for the synthesis of the AgNPs. Furthermore, it was found that the AgNPs showed good antioxidant efficacy (>78%, 0.1 mM) against 1,1-diphenyl-2-picrylhydrazyl. The process of synthesis is environmentally compatible and the synthesized AgNPs could be a promising candidate for many biomedical applications.

Biofabrication of nanogold from the flower extracts of Lantana camara.

The present investigation was done to explore the potential of Lantana camara (L. camara) flower in the fabrication of gold nanoparticles (AuNPs). The shape and size of AuNPs have been successfully controlled by introducing small amounts of L. camara flower extract. It produced spherical nanogold of average size 10.6 ± 2.9 nm without any aggregation and showed significant photocatalytic degradation activity of the methylene blue (>62%, 10 mg/L) in the presence of solar light. In addition, the experimental approach is inexpensive, rapid and eco-friendly for industrial scale production of nanoparticles.

One pot synthesis and characterization of gold nanocatalyst using Sacha inchi (Plukenetia volubilis) oil: Green approach.

In this report, a simple and cost-effective methodology has been developed to obtain gold nanoparticles (AuNPs) using Sacha inchi (Plukenetia volubilis) oil in the presence of sunlight. The spectroscopic and morphological properties of AuNPs were characterized by using UV-vis spectroscopy, transmission electron microscopy (TEM), particle size analyzer, and X-ray diffraction (XRD). UV-vis and TEM reveal that the nanostructure of the gold particles has surfaced plasmon resonance at 515-520nm and is almost spherical in shape with an average size of 5-15nm. XRD studies confirmed the face cubic center (fcc) unit cell structure of AuNPs. The as-synthesized AuNPs showed remarkable photocatalytic decomposition of the methylene blue (>75%) without using any reducing agent and weak antioxidant activity (21-16%) against 1,1-diphenyl-2-picrylhydrazyl at the different sunlight exposure times. The experimental approach is promising and suggested that the sunlight is a good source of energy for enhancement of AuNP synthesis via Sacha inchi oil and its photocatalytic activity.

In vitro evaluation of silver nanoparticles cytotoxicity on Hepatic cancer (Hep-G2) cell line and their antioxidant activity: Green approach for fabrication and application.

In this article, biosynthesis of silver nanoparticles (AgNPs) using Andean Mora (Rubus glaucus Benth.) leaf has been reported. Different analytical techniques including UV-vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used for the characterization of AgNPs. The initial appearance of color change with the intense surface plasmon resonance (SPR) bands around 440-455 in UV-visible spectra revealing the formation of AgNPs. The TEM image showed the AgNPs to be anisotropic, quasi-spherical in shape with sizes in the range of 12-50nm. On the other hand, XRD studies revealed the formation of face-centered cubic structure for AgNPs. The surface modified AgNPs showed no cytotoxicity at the concentration ranging from 0.01µM to 1.0µM on the Hepatic cancer (Hep-G2) cell line and observed antioxidant efficacy >70% at the concentration 0.05mM/0.20mL against 1, 1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that AgNPs could be used effectively in future drug delivery systems and other biomedical concerns.

Peptides conjugated to silver nanoparticles in biomedicine - a "value-added" phenomenon.

Nanotechnology is gaining impetus in the present century and particularly the use of nanoparticles (NPs), whose properties are significantly different from the larger matter. These have found wider and potential applications in the fields of medicine, energy, cosmetics, environment and biomedicine. Among the NPs, silver nanoparticles (AgNPs) are of particular interest for scientists and technologists due to their unique physico-chemical and biological properties. Besides, AgNPs by themselves also possess broad-spectrum microbial activity, which has further expanded their application in both academia and industries. On the other hand, research and drug discovery in the field of peptides is surging. Chemistry and biology of peptides have seen a renaissance in this century as many of the peptide-based therapeutics have entered the market and many more are in the different phases of clinical trials. To fuel this, peptides have also found numerous applications in nanotechnology. Taking advantage of these two scenarios, namely, AgNPs and peptides, conjugation of these entities have emerged as a powerful technique and have opened the doors for a new revolution. Keeping this motivation in mind, we here present a mini-review on the combined concept of AgNPs and peptides.

One pot phytosynthesis of gold nanoparticles using Genipa americana fruit extract and its biological applications.

In this article, rapid one pot synthesis of gold nanoparticles (GNPs) using an eco-friendly extract of Genipa americana L. fruit is described. Electrospray ionization mass spectrometry (ESI-MS) and Fourier transform infrared (FTIR) spectroscopic studies demonstrated that small molecules such as genipin, genipaol, geniposide and ranolazine can act as reducer as well as stabilizers. The monodispersed, spherical GNPs were further characterized by UV-vis spectroscopy at λmax=535 nm, transmission electron microscopy (TEM), dynamic light scattering (DLS) and X-ray diffraction (XRD) analysis. This synthetic approach offers a greener and alternate route to the preparation of GNPs free from toxic chemical components and stable for 6-7 months under room temperature. The green synthesized GNPs showed weak antioxidant efficacy against 1,1-diphenyl-2-picrylhydrazyl and no cytotoxicity against A-549 and HeLa human cancer cell lines, from lung and cervix. This study opens a new industrial scope of G. americana fruit in nanoscience and as surface modified GNPs can be developed into a successful drug carrier for future pharmaceutical products.

Green approach for fabrication and applications of zinc oxide nanoparticles.

Zinc oxide nanoparticles (ZnO-NPs) are known to be one of the multifunctional inorganic compounds which are widely used in everyday applications. This study aims to fabricate ZnO-NPs using grapefruit (Citrus paradisi) peel extract with particle size ranging from 12 to 72 nm. Structural, morphological, and optical properties of the synthesized nanoparticles have been characterized by using UV-Vis spectrophotometer, TEM, DLS, and FTIR analysis. They show the significant photocatalytic degradation efficiency (>56%, 10 mg/L, 6 h) against methylene blue and antioxidant efficacy (≥80% for 1.2 mM) against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green ZnO-NPs could be used effectively in environmental safety applications and also can address future medical concerns.

Synthesis of silver nanoparticles using Sacha inchi (Plukenetia volubilis L.) leaf extracts.

Silver nanoparticles (AgNPs) are fabricated using Sacha inchi (SI) or (Plukenetia volubilis L.) leaf extract as non-toxic reducing agent with particle size ranging from 4 to 25 nm. Optical, structural and morphological properties of the synthesized nanoparticles have been characterized by using Visual, UV-Vis spectrophotometer, transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. Selected area electron diffraction (SAED) confirmed the formation of metallic Ag. Infrared spectrum measurement was carried out to hypothesize the possible phytochemicals responsible for stabilization and capping of the AgNPs. It shows the significant antioxidant efficacy in comparison with SI leaf extracts against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green AgNPs could be used effectively in future engineering and medical concerns.

Sonochemical synthesis of silver nanoparticles using starch: a comparison.

A novel approach was applied to synthesize silver nanoparticles using starch under sonication. Colloidal silver nanoparticles solution exhibited an increase of absorption from 420 to 440 nm with increase starch quantity. Transmission electron microscopy followed by selected area electron diffraction pattern analysis indicated the formation of spherical, polydispersed, amorphous, silver nanoparticles of diameter ranging from 23 to 97 nm with mean particle size of 45.6 nm. Selected area electron diffraction (SAED) confirmed partial crystalline and amorphous nature of silver nanoparticles. Silver nanoparticles synthesized in this manner can be used for synthesis of 2-aryl substituted benzimidazoles which have numerous biomedical applications. The optimized reaction conditions include 10 ml of 1 mM AgNO3, 25 mg starch, 11 pH range, and sonication for 20 min at room temperature.

Arsenic in volcanic geothermal fluids of Latin America.

Numerous volcanoes, hot springs, fumaroles, and geothermal wells occur in the Pacific region of Latin America. These systems are characterized by high As concentrations and other typical geothermal elements such as Li and B. This paper presents a review of the available data on As concentrations in geothermal systems and their surficial discharges and As data on volcanic gases of Latin America. Data for geothermal systems in Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Ecuador, Bolivia, and Chile are presented. Two sources of As can be recognized in the investigated sites: Arsenic partitioned into volcanic gases and emitted in plumes and fumaroles, and arsenic in rocks of volcanic edifices that are leached by groundwaters enriched in volcanic gases. Water containing the most elevated concentrations of As are mature Na-Cl fluids with relatively low sulfate content and As concentrations reaching up to 73.6 mg L⁻¹ (Los Humeros geothermal field in Mexico), but more commonly ranging from a few mg L⁻¹ to tens of mg L⁻¹. Fluids derived from Na-Cl enriched waters formed through evaporation and condensation at shallower depths have As levels of only a few µg L⁻¹. Mixing of Na-Cl waters with shallower meteoric waters results in low to intermediate As concentrations (up to a few mg L⁻¹). After the waters are discharged at the ground surface, As(III) oxidizes to As(V) and attenuation of As concentration can occur due to sorption and co-precipitation processes with iron minerals and organic matter present in sediments. Understanding the mechanisms of As enrichment in geothermal waters and their fate upon mixing with shallower groundwater and surface waters is important for the protection of water resources in Latin America.

One century of arsenic exposure in Latin America: a review of history and occurrence from 14 countries.

The global impact on public health of elevated arsenic (As) in water supplies is highlighted by an increasing number of countries worldwide reporting high As concentrations in drinking water. In Latin America, the problem of As contamination in water is known in 14 out of 20 countries: Argentina, Bolivia, Brazil, Chile, Colombia, Cuba, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Peru and Uruguay. Considering the 10 µg/L limit for As in drinking water established by international and several national agencies, the number of exposed people is estimated to be about 14 million. Health effects of As exposure were identified for the first time already in the 1910s in Bellville (Córdoba province, Argentina). Nevertheless, contamination of As in waters has been detected in 10 Latin American countries only within the last 10 to 15 years. Arsenic is mobilized predominantly from young volcanic rocks and their weathering products. In alluvial aquifers, which are water sources frequently used for water supply, desorption of As from metal oxyhydroxides at high pH (>8) is the predominant mobility control; redox conditions are moderate reducing to oxidizing and As(V) is the predominant species. In the Andes, the Middle American cordillera and the Transmexican Volcanic Belt, oxidation of sulfide minerals is the primary As mobilization process. Rivers that originate in the Andean mountains, transport As to more densely populated areas in the lowlands (e.g. Rímac river in Peru, Pilcomayo river in Bolivia/Argentina/Paraguay). In many parts of Latin America, As often occurs together with F and B; in the Chaco-Pampean plain As is found additionally with V, Mo and U whereas in areas with sulfide ore deposits As often occurs together with heavy metals. These co-occurrences and the anthropogenic activities in mining areas that enhance the mobilization of As and other pollutants make more dramatic the environmental problem.