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Aim: The objective of this study was to analyze the antitumor effect of BisBAL NP in a mouse melanoma model. Material and Methods: The antitumor activity of BisBAL NP on murine B16-F10 melanoma cells was determined both in vitro (PrestoBlue cell viability assay and Live/Dead fluorescence) and in vivo, in a mouse model, with the following 15-day treatments: BisBAL NP, negative control (PBS), and cell-death control (docetaxel; DTX). Mouse survival and weight, as well as the tumor volume, were recorded daily during the in vivo study. Results: BisBAL NP were homogeneous in size (mean diameter, 14.7 nm) and bismuth content. In vitro, 0.1 mg/mL BisBAL NP inhibited B16-F10 cell growth stronger (88%) than 0.1 mg/mL DTX (82%) (*p Conclusion: BisBAL NP decreased the tumor growing in a mouse melanoma model without secondary effects, constituting an innovative low-cost alternative to treat melanoma.

Tracking Saharan–Sahelian dust across the globe is essential to elucidate its effects on Earth’s climate, radiation budget, hydrologic cycle, nutrient cycling, and also human health when it seasonally enters populated/industrialized regions of Africa, Europe, and North America. However, the elemental composition of mineral dust arising locally from construction activities and aeolian soil resuspension overlaps with African dust. Therefore, we derived a novel “isotope-resolved chemical mass balance” (IRCMB) method by employing radiogenic strontium, neodymium, and hafnium isotopes to accurately differentiate and quantitatively apportion collinear proximal and synoptic-scale crustal and anthropogenic mineral dust sources. IRCMB was applied to two air masses that transported African dust to Barbados and Texas to track particulate matter (PM) spikes at both locations. During Saharan–Sahelian intrusions, the radiogenic content of urban PM(2.5) increased with respect to (87)Sr/(86)Sr and (176)Hf/(177)Hf but decreased in terms of (143)Nd/(144)Nd, demonstrating the ability of these isotopes to sensitively track African dust intrusions even in complex metropolitan atmospheres. The principal aerosol strontium, neodymium, and hafnium end members were concrete dust and soil, soil and motor vehicles, and motor vehicles and North African dust, respectively. IRCMB separated and quantified local soil and distal crustal dust even when PM(2.5) concentrations were low, opening a promising source apportionment avenue for urbanized/industrialized atmospheres.

Treatment and reuse of some produced waters is made difficult due to their hypersalinity, high concentrations of myriad other dissolved and suspended components, specialized technology requirements (modularity, portability, and short residence times), and lack of existing information on their processing. In this work, produced water containing ∼100,000 mg/L total dissolved solids from the Permian Basin was coagulated with aluminum chlorohydrate (ACH) and flocculated with an anionic high molecular weight organic polymer prior to dissolved air flotation (DAF) and sedimentation to reduce turbidity to4 NTU and iron0.8 mg/L (95% removal in both cases) with a total coagulation-flocculation-sedimentation/flotation residence time of only 5 min. Two advantages of DAF over sedimentation were noted: (i) DAF required only half the dosage of the pre-hydrolyzed ACH coagulant to remove ∼90% of turbidity and iron even without the organic polymeric flocculant and (ii) DAF even operated successfully without ACH coagulation (i.e., using only the organic polymeric flocculant) evidencing its lower chemical dosing needs. Further, DAF attained all water quality and operational goals at a recycle ratio of only 12% demonstrating that it outperformed sedimentation to generate clean brine at relatively reduced excess energies necessary for air saturation. Higher DAF recycle ratios reduced turbidity and iron removal possibly due to floc breakage. Colloids were effectively destabilized by double layer compression (due to high water salinity), charge neutralization (via adsorption of Al

We present novel chemical separation protocols for isotopic analysis of low mass aliquots (0.3 mg and 25 mg) of several reference materials and real-world samples of relevance to urban airborne particulate matter (PM) investigations. A high-yielding gravity flow column chromatography scheme was developed for facile and quantitative separation of Sr, Nd, and Hf prior to multi collector – inductively coupled plasma – mass spectrometry (MC-ICP-MS). Because we are interested in isolating and accurately quantitating individual anthropogenic and natural aerosol sources in complex industrial/metropolitan atmospheric environments, laboratory protocols were optimized using National Institute of Standards and Technology Standard Reference Material (SRM) 1648a (urban atmospheric PM), SRM 1633b (coal fly ash), and European Commission standards BCR-723 (vehicular road dust), and BCR-2 (basalt rock standard). Sr, Nd, and Hf procedural blanks from column chromatography were low (averaging only 37 pg, 17 pg, 11 pg, respectively) and recoveries were high (averaging 95%, 82%, and 92%, respectively). A volume-adjustment protocol was established using isotope reference solutions SRM 987 (SrCO(3)), JNdi (Nd(2)O(3)), and in-house Hf standards to dilute the dried samples prior to MC-ICP-MS based on projected uncertainties for low sample masses. (87)Sr/(86)Sr, (143)Nd/(144)Nd, and (176)Hf/(177)Hf isotopic ratios in SRM 1648a, BCR-723, and SRM 1633b are reported for the first time that can serve as provisional reference values. The novel method was used to characterize isotopic ratios and elemental abundances in two anthropogenic urban aerosol sources, namely motor vehicles and petroleum refining using airborne fine PM collected in a vehicular tunnel and fluidized-bed catalytic cracking catalysts, respectively. Two other important mineral-rich urban PM sources, namely soil (i.e., resuspended crustal material) and concrete/cement dust (i.e., construction activity) were also characterized. These are the first isotopic measurements in these environmental compartments and were compared with literature data for long-range transported North African dust, which is a prominent summertime PM source in urban regions in southeastern United States. We demonstrate the capability of coupled Sr-Nd-Hf isotopes to uniquely trace different mineral dust sources with overlapping elemental composition (Sahara-Sahel region, local soil, and concrete/cement) and accurately isolate various urban PM sources demonstrating the superiority of isotopic markers over elemental tracers.

We quantify the contributions of long-range and regionally transported aerosols to ambient primary PM(2.5) and PM(10) in a representative United States industrialized/urban atmosphere via detailed elemental analysis and chemical mass balance (CMB) modeling after identifying their presence using a variety of publicly available satellite data/information, software products, and synoptic-scale aerosol models. A year-long study in Houston, Texas identified North African dust as the principal long-range global source of primary particulate matter (PM). CMB estimated transatlantic dust from the Sahara-Sahel region to be dominant in the summer months contributing an average of 3.5 μg m(−3) to PM(2.5) and 7.9 μg m(−3) to PM(10) during May–August, i.e., the active Saharan dust season. Biomass burning was the chief source of regionally transported PM impacting air quality on different occasions throughout the year depending on the fire location. Four major biomass combustion events affecting air quality in Texas were calculated to contribute an average of 1.3 μg m(−3) to PM(2.5) and 1.4 μg m(−3) to PM(10) in corresponding samples whose origins were tracked to Canada, southeastern states of USA, and Central America using fire maps, HYSPLIT back trajectories, and the Navy Aerosol Analysis and Prediction System global aerosol model. Elemental concentrations and signature ratios revealed significant mixing of potassium, rare earth metals, and vanadium from proximal and distal crustal (natural) sources with anthropogenically emitted PM. This demonstrates the need to isolate the non-mineral components of these metals to employ them as tracers for primary PM emitted by biomass burning, petroleum refineries, and oil combustion. Transboundary contributions to primary PM(2.5) were 1.5 μg m(−3) and 3.1 μg m(−3) to PM(10) adding 16% to annual average mass concentration of both size fractions demonstrating that local sources were primarily responsible for ambient air quality with non-trivial contributions from international and interstate sources. Rigorously identifying and quantifying aerosol sources assists in improving air quality management policies designed to protect public health and comply with ever-decreasing federal PM standards that allow state agencies to exclude contributions that are not reasonably controllable or preventable from regulatory decisions and actions.

Virus destabilization and inactivation are critical considerations in providing safe drinking water. We demonstrate that iron electrocoagulation simultaneously removed (via sweep flocculation) and inactivated a non-enveloped virus surrogate (MS2 bacteriophage) under slightly acidic conditions, resulting in highly effective virus control (e.g., 5-logs at 20 mg Fe/L and pH 6.4 in 30 min). Electrocoagulation simultaneously generated H2O2 and Fe(II) that can potentially trigger electro-Fenton reactions to produce reactive oxygen species such as •OH and high valent oxoiron(IV) that are capable of inactivating viruses. To date, viral attenuation during water treatment has been largely probed by evaluating infective virions (as plaque forming units) or genomic damage (via the quantitative polymerase chain reaction). In addition to these existing means of assessing virus attenuation, a novel technique of correlating transmission electron micrographs of electrocoagulated MS2 with their computationally altered three-dimensional electron density maps was developed to provide direct visual evidence of capsid morphological damages during electrocoagulation. The majority of coliphages lost at least 10-60% of the capsid protein missing a minimum of one of the 5-fold and two of 3- and 2-fold regions upon electrocoagulation, revealing substantial localized capsid deformation. Attenuated total reflectance-Fourier transform infrared spectroscopy revealed potential oxidation of viral coat proteins and modification of their secondary structures that were attributed to reactive oxygen species. Iron electrocoagulation simultaneously disinfects and coagulates non-enveloped viruses (unlike conventional coagulation), adding to the robustness of multiple barriers necessary for public health protection and appears to be a promising technology for small-scale distributed water treatment.

The objective of this work was to analyze the antimicrobial and antibiofilm activities of bismuth lipophilic nanoparticles (BisBAL NPs) incorporated into chitosan-based membranes. Chitosan-based membranes were homogeneously embedded with BisBAL NPs, confirming the bismuth presence by scanning electron microscopy. The tensile strength of chitosan-based membrane alone or with BisBAL NPs showed similar results as elongation, suggesting that BisBAL NP addition did not affect membrane mechanical properties. Chitosan-based membranes complemented with 100 µM of BisBAL NPs caused a complete inhibition of biofilm formation and a 90-98% growth inhibition of six different oral pathogens. Cytotoxicity studies revealed that 80% of human gingival fibroblasts were viable after a 24-h exposure to the chitosan-based membrane with 100 µM of BisBAL NPs and collagen. Altogether, we conclude that the biological properties of chitosan-based membranes supplemented with BisBAL NPs could be a very interesting option for tissue regeneration.

It is imperative to understand the behavior of enveloped viruses during water treatment to better protect public health, especially in the light of evidence of detection of coronaviruses in wastewater. We report bench-scale experiments evaluating the extent and mechanisms of removal and/or inactivation of a coronavirus surrogate (ϕ6 bacteriophage) in water by conventional FeCl3 coagulation and Fe(0) electrocoagulation. Both coagulation methods achieved ∼5-log removal/inactivation of ϕ6 in 20 min. Enhanced removal was attributed to the high hydrophobicity of ϕ6 imparted by its characteristic phospholipid envelope. ϕ6 adhesion to freshly precipitated iron (hydr)oxide also led to envelope damage causing inactivation in both coagulation techniques. Fourier transform infrared spectroscopy revealed oxidative damages to ϕ6 lipids only for electrocoagulation consistent with electro-Fenton reactions. Monitoring ϕ6 dsRNA by a novel reverse transcription quantitative polymerase chain reaction (RT-qPCR) method quantified significantly lower viral removal/inactivation in water compared with the plaque assay demonstrating that relying solely on RT-qPCR assays may overstate human health risks arising from viruses. Transmission electron microscopy and computationally generated electron density maps of ϕ6 showed severe morphological damages to virus' envelope and loss of capsid volume accompanying coagulation. Both conventional and electro- coagulation appear to be highly effective in controlling enveloped viruses during surface water treatment.

Molybdenum (Mo) is a key cofactor in enzymes used for nitrogen (N) fixation and nitrate reduction, and the low availability of Mo can constrain N inputs, affecting ecosystem productivity. Natural atmospheric Mo aerosolization and deposition from sources such as desert dust, sea‐salt spray, and volcanoes can affect ecosystem function across long timescales, but anthropogenic activities such as combustion, motor vehicles, and agricultural dust have accelerated the natural Mo cycle. Here we combined a synthesis of global atmospheric concentration observations and modeling to identify and estimate anthropogenic sources of atmospheric Mo. To project the impact of atmospheric Mo on terrestrial ecosystems, we synthesized soil Mo data and estimated the global distribution of soil Mo using two approaches to calculate turnover times. We estimated global emissions of atmospheric Mo in aerosols (

The primary objective of this research is to accurately estimate light-duty vehicles' (LDVs') emissions of PM

The objective of this study was to determine the antimicrobial potential of AH plus supplemented with bismuth lipophilic nanoparticles (BisBAL NPs) on the growth of Enterococcus faecalis isolated from patients with endodontic infections. BisBAL NPs, synthesized with the colloidal method, were characterized, in its pure form or AH Plus-absorbed, by energy-dispersive X-ray spectroscopy and scanning electron microscopy (EDS-SEM). Antimicrobial activity was evaluated with disc diffusion assays, and antibiofilm activity with fluorescence microscopy. BisBAL NP-supplemented AH Plus had a 4.9 times higher antimicrobial activity than AH Plus alone ( p = 0.0001). In contrast to AH Plus alone, AH Plus supplemented with BisBAL NP inhibited E. faecalis biofilm formation. The sealing properties of AH plus were not modified by the incorporation of BisBAL NPs, which was demonstrated by a 12-day split-chamber leakage assay with daily inoculation, which was used to evaluate the possible filtration of E. faecalis. Finally, BisBAL NP-supplemented AH plus-BisBAL NPs was not cytotoxic for cultured human gingival fibroblasts. Their viability was 83.7% to 89.9% after a 24-h exposure to AH Plus containing 50 and 10 µM BisBAL NP, respectively. In conclusion, BisBAL NP-supplemented AH Plus constitutes an innovative nanomaterial to prevent re-infection in endodontic patients without cytotoxic effects.

Rene Hernandez-Delgadillo,1 Claudia María García-Cuéllar,2 Yesennia Sánchez-Pérez,2 Nayely Pineda-Aguilar,3 Marco Antonio Martínez-Martínez,1 Eyra Elvyra Rangel-Padilla,1 Sergio Eduardo Nakagoshi-Cepeda,1 Juan Manuel Solís-Soto,1 Rosa Isela Sánchez-Nájera,1 María Argelia Akemi Nakagoshi-Cepeda,1 Shankararaman Chellam,4 Claudio Cabral-Romero1 1Universidad Autónoma de Nuevo León, UANL, Facultad de Odontología, Laboratorio de Biología Molecular, Monterrey, Nuevo León, México; 2Subdirección de Investigación Básica, Instituto Nacional de Cancerología, CDMX, México; 3Centro de Investigación en Materiales Avanzados, S.C. (CIMAV), Unidad Monterrey, Nuevo León, México; 4Texas A&M University, College Station, TX, USA Aim: The objective of this study was to evaluate the antitumor activity of lipophilic bismuth nanoparticles (BisBAL NPs) on breast cancer cells.Materials and methods: The effect of varying concentrations of BisBAL NPs was evaluated on human MCF-7 breast cancer cells and on MCF-10A fibrocystic mammary epitheliocytes as noncancer control cells. Cell viability was evaluated with the MTT assay, plasma membrane integrity was analyzed with the calcein AM assay, genotoxicity with the comet assay, and apoptosis with the Annexin V/7-AAD assay.Results: BisBAL NPs were spherical in shape (average diameter, 28 nm) and agglomerated into dense electronic clusters. BisBAL NP induced a dose-dependent growth inhibition. Most importantly, growth inhibition was higher for MCF-7 cells than for MCF-10A cells. At 1 µM BisBAL NP, MCF-7 growth inhibition was 51%, while it was 11% for MCF-10A; at 25 µM BisBAL NP, the growth inhibition was 81% for MCF-7 and 24% for MCF-10A. With respect to mechanisms of action, a 24-hour exposure of 10 and 100 µM BisBAL NP caused loss of cell membrane integrity and fragmentation of tumor cell DNA. BisBAL NPs at 10 µM were genotoxic to and caused apoptosis of breast cancer cells.Conclusion: BisBAL NP-induced growth inhibition is dose dependent, and breast cancer cells are more vulnerable than noncancer breast cells. The mechanism of action of BisBAL NPs may include loss of plasma membrane integrity and a genotoxic effect on the genomic DNA of breast cancer cells. Keywords: antitumor activity, bismuth nanoparticles, breast cancer, chemotherapy, cytotoxicity

Uncertainty is inherent in experimentation, modeling, and analysis. Variations and errors in parameter estimates or physical processes are unavoidable and can affect the reliability of model predictions. Therefore understanding the role of uncertainty is embedded in the process of modeling and approximating the real world. In this manuscript we consider uncertainty propagation in a theoretical model of water/wastewater treatment. In dead-end microfiltration contaminated water is fed through a membrane that filters out colloids, bacteria, and protozoa. However, these particles foul the membrane reducing the filter productivity, which is alleviated by periodically reversing the flow, i.e. backwashing. We investigate how uncertainty in sensitive parameter estimates propagates to the estimates of the optimal amount of volume of water that is filtered in a fixed time period and the associated backwashing timing and duration. We find that the model provides conservative estimates for the total volume since the uncertainty is not propagated symmetrically with respect to over and underestimating specific measurable quantities. The uncertainty in the timing is more symmetric implying that there is essentially an equal amount of uncertainty for increasing or decreasing the frequency and duration of backwashing. We identified biofilm production as propagating the most uncertainty in the volume estimate. The fouling rate has the most effect on the timing estimates. Additionally we explored the affect of asymmetric parameter distributions and find that, for most parameters, asymmetry does not lead to increased asymmetry in predicted optimal regimes, implying that uncertainty in the skewness is likely not an issue.

A commixture of gasphase compounds including carbon monoxide (CO), sulphur dioxide (SO2), volatile organic compounds (VOCs) and trace metals were collected at a site located at the urban/industrial interface in Houston, Texas. Positive Matrix Factorization (PMF) analysis yielded nine factors: gas/crude oil (21.3±5.5%), isoprene emission (17.0±7.1%), Si-rich (14.6±1.3%), liquefied petroleum gas (LPG) (11.2±4.0%), traffic (10.6±0.4%), Fluidized-bed Catalytic Cracking (FCC)/high temperature operations (7.2±4.3%), oil refinery (6.8±0.9%), soil and road dust (6.2±0.6%), and petrochemical industries (5.0±5.0%). Daytime and nighttime PMF runs were carried out to see potential differences among and within emission sources. Notable findings include: (1) Nocturnal isoprene emission was identified from traffic exhaust and industrial sources. (2) LPG emissions were higher during the day most likely due to temperature dependent evaporative processes. (3) V/Ni and SO2/V ratios reveal greater contribution from crude oil in the merged natural gas/crude oil emission factor. Corrosion might be responsible for emitting metals (i.e., Cr, Cu, Mo, Ni) from oil refineries during nighttime. (4) In the soil and road dust factor, metals relevant to plant physiological processes are mostly retained by the plants while the lanthanoids and other metals (i.e. Y, Pb, Mn, Ga, Ba) are more prone to physical removal during the day. (5) FCC/high temperature operations are dominated by metals at night. (6) The traffic factor increases during the day possibly due to the higher number of vehicles. Bivariate polar plots suggest the Houston Ship Channel area as the primary emission source for LPG, natural gas/crude oil, FCC/high temperature operations, and petrochemical industries.

One promising water management strategy during hydraulic fracturing is treatment and reuse of flowback/produced water. In particular, the saline flowback water contains many of the chemicals employed for fracking, which need to be removed before possible reuse as “frac water.” This manuscript targets turbidity along with one of the additives; borate-based cross-linkers used to adjust the rheological characteristics of the frac-fluid. Alum and ferric chloride were evaluated as coagulants for clarification and boron removal from saline flowback water obtained from a well in the Eagle Ford shale. Extremely high dosages (> 9000 mg/L or 333 mM Al and 160 mM Fe) corresponding to Al/B and Fe/B mass ratios of ∼70 and molar ratios of ∼28 and 13 respectively were necessary to remove ∼80% boron. Hence, coagulation does not appear to be feasible for boron removal from high-strength waste streams. X-ray photoelectron spectroscopy revealed B O bonding on surfaces of freshly precipitated Al(OH)3(am) and Fe(OH)3(am) suggesting boron uptake was predominantly via ligand exchange. Attenuated total reflection-Fourier transform infrared spectroscopy provided direct evidence of inner-sphere boron complexation with surface hydroxyl groups on both amorphous aluminum and iron hydroxides. Only trigonal boron was detected on aluminum flocs since possible presence of tetrahedral boron was masked by severe Al O interferences. Both trigonal and tetrahedral conformation of boron complexes were identified on Fe(OH)3 surfaces.

Paired PM10 and fine particulate matter (PM2.5) samples were collected indoor and outdoor at a fully mechanically ventilated high school in the ultraindustrialized ship channel region of Houston, Texas over a two-month period. The primary foci of this research are to measure the elemental composition of ambient outdoor and indoor coarse particulate matter (PM10-2.5), characterize aerosol infiltration/ventilation, and obtain clues to their origins. Several metallic hazardous air pollutants were detected inside the school but at concentrations lower than even the most rigorous indoor air quality benchmarks. Only chromium may have potentially posed a hazard based on indoor air quality standards set by the California Environmental Protection Agency. Indoor-to-outdoor (I/O) mass abundance ratios for some metals (Li, Be, Si, Ti, Cr, Co, Ni, Zn, As, Se, Zr, Cd, Sn, Sb, Hf, and Pb) were significantly greater than 1 in PM10-2.5, suggesting corresponding indoor sources in the PM10-2.5 size range. Some other metals (Al, K, Ca, V, Mn, Fe, Cu, Ga, Rb, Sr, Y, Mo, Ce, Pr, Nd, Sm, Gd, Dy, Yb, and U) in PM10-2.5 had I/O ratios close to one suggesting they had predominantly outdoor origins. Enrichment factors of several metals including light rare earths (e.g. Cu, Sb, Pb, Mo, Cd, La, Ce, Pr, Nd, and Sm) with respect to local soil were overall the highest both indoors and outdoors, illustrating their anthropogenic origins. Several lines of evidence including light lanthanoid ratios, simultaneous La–Ce-Sm variations (ternary diagrams), and correlations with cracking catalysts indicated that petroleum refineries are principally responsible for the elevated lanthanoid concentrations. Rare earth element analysis revealed shifts between transient catalyst releases from petroleum refining operations and windblown soil resuspension as their dominant sources.

One of the central problems in membrane implementation is that foulants deposit on surfaces of microfilters employed for water and wastewater treatment and reuse, reducing their productivity. In an effort to remove as much of the deposited materials as possible and maintain the flux, the direction of flow across these membranes is regularly and frequently reversed. However, backwashing only removes the loosely or reversibly bound materials necessitating the entire system to be taken off-line for chemical cleaning when fouling increases beyond a threshold value. We recently presented a mathematically rigorous methodology to determine timing and duration of backwashes so as to delay membrane chemical cleaning and reduce associated operational complexity and costs. By considering an optimal control formulation, using the flow direction as the control variable, the optimal timing and maximum volume of water that can be microfiltered in a given time period were predicted during dead-end filtration of bacterial suspensions. The value of these predictions depend on our ability to accurately and precisely estimate input parameters such as the clean membrane resistance, influent water quality estimates, and biofilm and exo-polymeric substance formation rates and effects. These estimates are inherently uncertain leading to uncertainty in the predictions, which can be rigorously quantified using Sobol indices. These provide a global method for assessing the sensitivity of model predictions (e.g. optimal timing and volume filtered) with respect to variations in the inputs.

The most common treatment to trichomoniasis is the use of metronidazole; however several studies have shown that at least 5% of clinical cases of trichomoniasis are caused by parasites resistant to the drug. Lipophilic bismuth nanoparticles (BisBAL NPs) have an important antimicrobial activity; however the influence of BisBAL NPs on human parasites has not been studied. The objective of this study was to determine the effect of bismuth lipophilic nanoparticles on Trichomonas vaginalis growth. The bismuth nanoparticles synthesized by colloidal method are composed of ≥ 100 nm crystallites and have a spherical structure, agglomerating into clusters of small nanoparticles. Based on cell viability assays and fluorescence microscopy, Trichomonas vaginalis growth was inhibited with the addition of 62.5–125 μg/mL of BisBAL NPs. Fluorescence micrographs showed live T. vaginalis in absence of any drug treatment and after exposed for 24 h. with 500 μg/mL of BisBAL NPs or 1.3 μg/mL metronidazole a dark background was observed with cellular debris stain. In summary, here we present evidence for first time of the antiparasitic activity of lipophilic bismuth nanoparticles being as effective as metronidazole to interfere with T. vaginalis growth. BisBAL nanoparticles could be an interesting alternative to treat and prevent parasitic infections.

Pretreatment with coupled aluminum electrocoagulation (EC) – microfiltration (MF) successfully mitigated colloidal and organic fouling during nanofiltration (NF) of an inland natural brackish surface water. Natural organic matter (NOM) removal by EC was enhanced due to (i) greater degree of NOM protonation by maintaining a slightly acidic pH during electrolysis, compared with that of minimum aluminum solubility (pH of 5.5 compared to 6.2), (ii) providing sufficient contact time during electrolysis and flocculation by utilizing intermediate current density (10 mA/cm2), and (iii) combination of charge neutralization and sweep coagulation by increasing aluminum dosage. Direct evidence for removal of the hydrophobic fraction of NOM along with a portion of the hydrophilic moieties by EC-MF compared to MF-only was provided by attenuated total reflectance-Fourier transform infrared spectroscopy. NF flux profiles with EC-MF pretreatment of natural saline water were nearly identical to that of a model solution with similar ionic composition with no added NOM suggesting insignificant role of organic fouling. X-ray photoelectron spectroscopy showed trace amounts of CaCO3 precipitates after EC-MF pretreatment, confirmed by electron microscopy, that caused only minor flux decline. Finally, NF achieves excellent strontium removal as well as other divalent ions and NOM.

Outdoor emissions of primary fine particles and their contributions to indoor air quality deterioration were examined by collecting PM2.5 inside and outside a mechanically ventilated high school in the ultraindustrialized ship channel region of Houston, TX over a 2-month period. By characterizing 47 elements including lanthanoids (rare earth elements), using inductively coupled plasma-mass spectrometry, we captured indoor signatures of outdoor episodic emissions arising from nonroutine operations of petroleum refinery fluidized-bed catalytic cracking units. Average indoor-to-outdoor (I/O) abundance ratios for the majority of elements were close to unity providing evidence that indoor metal-bearing PM2.5 had predominantly outdoor origins. Only Co had an I/O abundance ratio >1 but its indoor sources could not be explicitly identified. La and 17 other elements (Na, K, V, Ni, Co, Cu, Zn, Ga, As, Se, Mo, Cd, Sn, Sb, Ba, W, and Pb), including air toxics were enriched relative to the local soil both in indoor an...

Bench-scale nanofiltration (NF) experiments were performed with two commercially available membranes having different ion rejection characteristics to assess dominant fouling mechanisms during inland brackish surface water desalination and the role of rejection on flux decline. The Foss Reservoir in the state of Oklahoma, USA was used as a representative natural brackish surface water source in these experiments. Both nanofilters rejected divalent cations to a very high extent (Mg>94% and Ca>92%) but exhibited substantially different rejections of monovalent cations (e.g. Na removals of 60% and 97%). A model solution formulated to have a similar ionic composition as the natural water but with no added natural organic matter (NOM) was also employed to isolate mineral scaling effects. The low monovalent ion rejecting membrane was predominantly fouled by NOM with only limited contributions from calcium carbonate scaling. In contrast, electron microscopy along with infrared and X-ray photoelectron spectroscopy revealed that both NOM and gypsum were major foulants for the membrane that highly rejected both mono- and divalent ions. The exacerbated flux decline for the more salt-rejecting nanofilter was attributed to the synergistic effects of NOM and gypsum on fouling coupled with the formation of a very compact organic foulant layer due to greater extent of Ca-NOM interactions and the higher ionic strength of the concentration polarization layer. These results demonstrate that the relative contributions of NOM and mineral scaling to flux decline during brackish surface water NF depends on membrane ion rejection characteristics. Hence, optimal membrane selection needs to balance total dissolved solids concentration of the product water with the need to minimize fouling.

Surfaces of two reverse osmosis (RO) membranes, one from each stage of a real-world pilot-plant operated in support of full-scale design of municipal water reuse, were extensively characterized to determine dominant foulants. Since the source wastewater was purified using extended aeration activated sludge, alum was also being added to the secondary clarifier to eliminate potential problems with colloidal sedimentation. Even though microfiltration (MF) was implemented to pretreat the secondary effluent prior to RO, significant aluminum fouling was detected by energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Peak shifts in Fourier transform infrared (FTIR) spectra and high resolution X-ray spectra indicated aluminum complexation with the membrane surface. Calcium and phosphorous (from added antiscalant) were also detected along with only weak signals from organic matter suggesting the dominance of inorganic fouling. These results demonstrate that chemicals added during wastewater reclamation can foul downstream membranes necessitating careful monitoring of existing wastewater treatment unit operations and RO pretreatment processes. One-step cleaning with EDTA at pH 11 successfully removed both aluminum and calcium and restored the flux to nearly that of the virgin membrane. In contrast, citric acid at pH 4 was effective in removing calcium but not aluminum and did not fully recover the flux. Hence, flux decline appears to be closely linked to aluminum rather than calcium deposition. Residues of EDTA and citric acid were detected on the cleaned membrane surface even following multiple rinse/washing cycles. Although this did not impact short-term flux recovery, the effects of such remnants on long-term membrane life and flux restoration following multiple cleaning cycles need further investigation.

Microfiltration and ultrafiltration are methods of removing colloidal impurities from water and wastewater. One of the major issues when dealing with the practical implementation of membranes is the reduction of water productivity as the foulants accumulate on the membrane surface or within the pores. Membrane regeneration by periodic backwashing is an effective method of reducing fouling; however, to date the timing and duration of the backwashing for effective fouling control is largely only empirically determined. In this manuscript, we present an optimal control formulation to determine the timing and duration for membrane regeneration by backwashing. In this formulation, we use the direction of the flow as the control variable and make predictions regarding the optimal protocol. We explicitly include irreversible attachment due to bacterial deposition and biofilm formation on the membrane and demonstrate that irreversible attachment of bacteria has important ramifications for the effective timing of hydraulic backwashes as well as the efficiency in producing clean water. In particular, we find that irreversible attachment and additional fouling due to exo-polymeric substance (EPS) production and biofilm formation decreases the maximum filtration volume. Additionally, as the effectiveness of membrane regeneration declines, the timing of the cycling is also altered. In general, including the role of EPS in biofouling substantially changes predictions of backwashing timing and implies important considerations for practical predictions.

The objective of this study was to analyze the antitumor activity of a hydrogel loaded with lipophilic bismuth nanoparticles on human cervical, prostate, and colon cancer cell lines. The effect of lipophilic bismuth nanoparticles on the viability of cancer cell lines (HeLa, DU145, and HCT-116) and non-cancer lung fibroblasts (HLF; LL 47[MaDo]) was determined with the MTT cell viability assay and compared with known antineoplastic drugs. The biocompatibility at an organismal level was verified in a murine model by histological examination. A lipophilic bismuth nanoparticle hydrogel at 50 µM time-dependently inhibited the growth of the three cancer cell lines, in a time-dependent way. A 1-hour exposure to 250 µM lipophilic bismuth nanoparticle hydrogel, inhibited the growth of the three cancer cell lines. The in-vitro efficacy of lipophilic bismuth nanoparticle was similar to the one of docetaxel and cisplatin, but without inhibiting the growth of non-cancer control cells. Histology confirmed the biocompatibility of lipophilic bismuth nanoparticles as there were no signs of cytotoxicity or tissue damage in any of the evaluated organs (kidney, liver, brain, cerebellum, heart, and jejunum). In conclusion, a lipophilic bismuth nanoparticle hydrogel is an innovative, low-cost alternative for the topical treatment of cervicouterine, prostate, and colon human cancers.

Reusing produced water for hydraulic fracturing simultaneously satisfies challenges of fresh water sourcing and the installation/operation of an extensive disposal well infrastructure. Herein, we systematically and rigorously investigate produced water treatment for reuse during hydraulic fracturing. Highly saline and turbid produced water from the Permian Basin was treated by adding chlorine as an oxidant, FeCl3 as the primary coagulant, and an anionic polymer to induce high rate sedimentation to generate “clean brine” by removing suspended solids and iron over a range of environmentally relevant temperatures. Mobile phone video capture, optical microscopy, and digital image/video analysis were employed to characterize floc morphology and measure its size and settling velocity. Conformational changes of the polymeric coagulant between 4 and 44 °C were inferred from viscosity and dynamic light scattering measurements providing clues to its performance characteristics. Floc settling velocities measured over the entire range of polymer dosages and temperatures were empirically modelled incorporating their fractal nature, average size, and the viscosity of the produced water using only a single fitting parameter. Juxtaposing the anionic polymer with the hydrolyzing metal-ion coagulant effectively destabilized the suspension and caused floc growth through a combination of enmeshment, adsorption and charge neutralization and inter-particle bridging as evidenced by Fourier transform infrared spectroscopy and thermogravimetric analysis. Very high turbidity (≥98%) and total iron (≥97%) removals were accomplished even with very short flocculation and sedimentation times of only 6 minutes each suggesting the feasibility of this approach to reuse produced water for hydraulic fracturing.

The objective of this study was to compare the antitumor activity of lipophilic bismuth nanoparticles (BisBAL NPs) and chlorhexidine (CHX) on human squamous cell carcinoma. BisBAL NPs were synthesized by colloidal method and characterized by energy dispersive X-ray spectroscopy in conjunction with scanning electron microscopy (EDS-SEM). The effect of BisBAL NPs and CHX on oral cancer cell line (CAL-27) and nontumor control cell human gingival fibroblasts (HGFs) was determined by MTT cell viability assay. The obtained results showed selective inhibition of CAL-27 cell growth by BisBAL nanoclusters. A 24 h exposition to 25 μM BisBAL NP decreased 91% of CAL-27 cell growth, while nontumor HGFs cells were unaffected by BisBAL NPs showing 90% of cell viability. In contrast, CHX kills both CAL-27 and HGFs with the same efficacy. 25 μM of CHX decreased 97% and 80% of tumor and nontumoral cell growth. BisBAL NP and CHX alter cell permeability suggesting that action mechanism may include loss of cell membrane integrity. Also, CHX and not BisBAL NP presented genotoxicity on genomic DNA of tumor cells. As conclusion, BisBAL NPs have a selective antitumor activity on human squamous cell carcinoma, unlike CHX which was cytotoxic for both tumoral and nontumoral control cells.

Chlorination-induced changes in the physicochemical characteristics of effluent organic matter (EfOM) and their role in fouling of hollow fiber polyvinylidene fluoride (PVDF) microfiltration membranes during wastewater reclamation was mechanistically investigated. Pre-chlorination strongly influenced pressure rise during constant flux forward filtration as well as hydraulically irreversible fouling by backwashing with low doses exacerbating it and high doses alleviating it. Dose-dependent fouling trends originated from alterations in EfOM size and polarity and consequently its interactions with the membrane based on whether applied chlorine concentrations were above or below a threshold value. Variations in macroscopic phenomena such as sorption tendency, streaming potential, and initial fouling upon exposure to pre-chlorinated EfOM were consistent with favorable adhesion energies calculated using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. Progressive fouling even though XDLVO theory predicted unfavorable EfOM-EfOM cohesive energies under all chlorination conditions demonstrated that hydrodynamics (permeation drag) dominated later stages of fouling. EfOM in the raw wastewater was largely deposited on the membrane surface resulting in compressible cake filtration. In contrast, pre-chlorination fragmented EfOM leading to intrapore fouling (standard blocking) at the beginning stages of filtration later transitioning to surface fouling (intermediate blocking).

The primary objective of this research is to accurately estimate light-duty vehicles' (LDVs') emissions of PM2.5 and PM10 over the course of a year within the property line of an inner-city school located adjacent to a heavily-trafficked interstate highway by measuring platinum group elements (PGEs – Rh, Pd, and Pt) along with 49 other major and trace elements. Amongst PGEs, ambient Pd concentrations were the highest, averaging 11 pg/m3 in PM10 and 4.0 pg/m3 in PM2.5 followed by Pt (3.5 pg/m3 in PM10 and 1.4 pg/m3 in PM2.5), and Rh (1.6 pg/m3 in PM10 and 0.52 pg/m3 in PM2.5). Simultaneous three-component variations in Rh, Pd, and Pt in both PM size classes at this surface site closely matched the composition of (i) a mixed random lot of recycled autocatalysts obtained from numerous LDVs and (ii) PM inside a proximal underwater tunnel open only to light-duty vehicles. Additionally, quantitative estimates of LDV contributions to ambient PM calculated by chemical mass balance modeling (CMB) were strongly correlated with PGE abundances. Therefore, PGEs predominantly originated from gasoline-driven motor vehicles validating them as unique LDV tracers. Further, CMB estimated that vehicles contributed 37% on average (12–67%) to PM10 and 49% on average (25–73%) to PM2.5. Evidence is also presented for a subset of other trace metals; i.e. Cu, As, Mo, Cd, and Sb to also be relatively strong LDV tracers. Results highlight the importance of measuring PGEs in addition to numerous other elements in PM to accurately apportion aerosols emanating from LDVs, which will better isolate public health and environmental impacts associated with the transportation sector.

Bismuth nanoparticles have many interesting properties to be applied in biomedical and medicinal sectors, however their safety in humans have not been comprehensively investigated. The objective of this research was to determine the cytotoxic effect of bismuth dimercaptopropanol nanoparticles (BisBAL NPs) on epithelial cells. The nanoparticles are composed of 18.7 nm crystallites on average and have a rhombohedral structure, agglomerating into chains-like or clusters of small nanoparticles. Based on MTT viability assay and fluorescence microscopy, cytotoxicity was not observed on monkey kidney cells after growing with 5 µM of BisBAL NPs for 24 h. Employing same techniques, identical results were obtained with human epithelial cells (HeLa), showing a not strain-dependent phenomenon. The absence of toxic effects on epithelial cells growing with BisBAL NPs was corroborated with long-time experiments (24-72 hrs.), showing no difference in comparison with growing control (cells without nanoparticles). Further, genotoxicity assays, comet assay and fluorescent microscopy and electrophoresis in bromide-stained agarose gel revealed no damage to genomic DNA of MA104 cells after 24 h. of exposition to BisBAL NPs. Finally, the effect of bismuth nanoparticles on protein synthesis was studied in cells growing with BisBAL NPs for 24 h. SDS-PAGE assays showed no difference between treated and untreated cells, suggesting that BisBAL NPs did not interfere with protein synthesis. Hence BisBAL NPs do not appear to exert cytotoxic effects suggesting their biological compatibility with epithelial cells.

This paper studies a co-design of solar generation-based nano-grid and water treatment in remote areas. The goal is to provide the minimum essential drinking water and electricity needs to communities in remote, underdeveloped regions such as Colonias in South Texas at the United States-Mexico border. It is shown that a portable nanofiltration treatment unit, powered by only a few photovoltaic (PV) panels augmented with batteries and supplemented with water storage tanks, offers crucial flexibility in accommodating solar-powered electricity service which is intermittent in its nature. Given the lack of infrastructure and associated primitive conditions in Colonias, the proposed planning and operation of the nano-grid leverages the flexibility of power consumption for the water filtration process to compensate for the fluctuating solar PV generation. A risk-tunable, scenario-based optimization is formulated to quantify the risks associated with the design, given different weather scenarios. The case study based on bench-scale experiments, optimization, and economic considerations coupled with historical weather data for targeted Colonias in Texas suggest the unique benefits of joint optimization of both electricity and water needs.

Reversible and irreversible fouling mechanisms for polyvinylidene fluoride (PVDF) hollow fiber membranes during constant flux microfiltration (MF) of secondary municipal wastewater effluent are reported. Infrared spectra of fouled membranes revealed a two-step mechanism for hydraulically irreversible surface deposition of foulants; initial binding of relatively hydrophobic molecules, which served as platform for further deposition of comparatively more hydrophilic molecules with progressive MF. Compressible cake filtration quantitatively described forward MF of the raw wastewater effluent. In contrast, analysis of fouling behavior after effluent organic matter (EfOM, measured as DOC) removal by different pretreatments revealed that the foulants deposited on the membrane surface are not the dominant reason for irreversible loss in permeability instead pointing to internal pore deposition as the main reason, which was verified by blocking law modeling over multiple filtration/backwashing cycles. Additionally, the extent of EfOM removal during pretreatment was not proportionally linked to consequent fouling, signifying the role of specific EfOM fractions in the feed water as being responsible for (ir)reversible fouling. Interestingly, MF of the raw wastewater effluent resulted in lower irreversible permeability loss when compared with pretreated wastewater, which was attributed to the cake layer serving as a dynamic membrane that reduced exposure of membrane pores to foulants.