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Women with primary ovarian insufficiency exhibit an unfavorable cardiovascular risk profile. A common cause for primary ovarian insufficiency is fragile X premutation (FXPC), and data on the cardiovascular risk factors in women with FXPC are scarce. We aimed to assess the prevalences of abnormal metabolic components among FXPC.Clinical, anthropometric and laboratory data were collected from 71 women with FXPC and compared to 78 women referred for counseling in an in-vitro fertilization clinic (control group). The mean ± SD ages of the FXPC and control groups were 33.5 ± 5.6 and 36.2 ± 5.3 years, respectively (p = 0.003). In a logistic regression analysis, the FXPC group had increased risks for hyperglycemia, hypertriglyceridemia, central obesity and low high-density lipoprotein cholesterol, of 21.8-fold (95% CI 2.7-175, p = 0.004), 6.9-fold (95% CI 2.5-18.7, p 0.0001), 3.1-fold (95% CI 1.4-6.9, p = 0.005) and 2.4-fold (95% CI 1.1-5.2, p = 0.03), compared to the control group. The FXPC group had 2.7-fold higher prevalence of two abnormal metabolic components; 19% met the full criteria of MetS, compared to 3% of the control group. Neither CGG repeats nor ovarian reserve markers were associated with metabolic risk.Carriers of fragile X premutation are at increased metabolic risk from early adulthood; waist circumference, glucose and lipid levels are particularly elevated. We recommend metabolic screening for all women with FMR1 premutation, to enable early interventions for prevention of long-term cardiovascular comorbidities.

PURPOSE To evaluate whether ethnicity affects the risk of full mutation expansion among females heterozygous for FMR1 premutation. METHODS Women who carry the FMR1 premutation alelle of Jewish origin who underwent fragile X prenatal diagnosis between 2011 and 2018 in two medical centers in Israel were included. The heterozygote women and fetuses were analyzed for the number of CGG repeats and AGG interruptions. RESULTS Seven hundred sixty-six subjects were included. Parental ethnicity was fully concordant in 592 cases (Jewish, Ashkenazi, and non-Ashkenazi). Ashkenazi compared with non-Ashkenazi heterozygotes have a significantly higher mean number of CGG repeats (68 ± 8.7, 64 ± 6.4 respectively, P = 0.03) and a lower mean number of AGG interruptions (0.89 ± 0.83, 1.60 ± 1.18 respectively, p = 0.0001). Overall, 56/198 (28.2%) fetuses of Ashkenazi heterozygotes had an expansion to a full mutation compared with 6/98 among the non-Ashkenazi (6.1%) (p = 0.001). Multivariate analysis demonstrated that, in addition to CGG repeats and AGG interruptions (which contributed 68.3% of variance), ethnicity is an independent risk factor for a full mutation expansion (odds ratio [OR] = 2.04, p

Tethered poly(acrylic acid) (PAA) chains, synthesized onto polysulfone (PSf) surfaces, were characterized with respect to surface topography and chain characteristics via AFM force spectroscopy. The tethered PAA chains were synthesized by surface activation with an impinging atmospheric pressure plasma stream (He, He/O2 and He/H2), followed by free-radical acrylic acid graft polymerization. The number average molecular weight of the tethered PAA chains was estimated to be of in the range of ∼13,000–35,000 with chain-chain separation of 1.5–2.4 nm. Deionized and high salinity water contact angles for the PAA-PSf surfaces were in the range of ∼ 29–38°, indicating hydrophilic surfaces, relative to 80° contact angle for the native hydrophobic PSf surface. In DI water the tethered PAA chains had significantly greater chain extension than in a high salinity aqueous environment. Ultrafiltration fouling stress tests with alginic acid in a high salinity water and post cleaning with non-saline water demonstrated permeability restoration of up to 90–100% for a PAA-PSf membrane relative to 50–70% for the native PSf membrane. The present study suggests the merit of exploring and optimizing surface modification of membranes for saline water filtration to reduce irreversible fouling and improve cleaning effectiveness using non-saline water.

A flexible RO (FLERO) membrane desalination configuration employing a pressure intensifier and partial concentrate recycle was investigated with respect to operational flexibility and specific energy consumption (SEC). Decomposition of FLERO configuration and its operation into a membrane processing and concentrate recycle units allows fluid flow regulation at low pressure and adjustable product water recovery. Operational analysis, along with experimental evaluation using a small-scale spiral wound system, demonstrated a desalting capability over a wide range of both permeate recovery and source water salinity. Moreover, in the FLERO configuration a relatively low-pressure pump can be used, even for seawater desalination. However, the SEC for the FLERO configuration is higher, at the same recovery and permeate productivity, relative to conventional single-pass with energy recovery. Nonetheless, given its operational flexibility, in terms of handling both a wide range of source water salinity and recovery and source water salinity and need for low-pressure RO water feed pump. Given the above, FLERO should be ideal for small-scale applications, particularly in remote locations, and field evaluation is warranted to establish its long-term benefits. Large-scale FLERO applications would depend on the availability of suitable energy recovery devices of sufficient efficiency for large desalination capacity.

The applicability of fouling indicators for real time performance assessment of UF feed pretreatment in RO seawater desalination was explored in a field study using an integrated seawater UF-RO desalination pilot plant. Fouling indictors were evaluated with respect to quantification of UF backwashability, unbackwashed fouling resistance and UF fouling rate. Feed water quality and coagulant dose demonstrated measurable impact on both UF fouling rate and effectiveness of foulant removal via UF backwash. Increased coagulant dose promoted higher rate of cake formation and in turn improved backwash efficiency. However, there was a maximum coagulant dose beyond which there was no further backwash improvement. Backwash effectiveness increased with higher backwash flux and duration, up to threshold upper limits, but declined as the filtration period increased above a threshold limit. Field tests during periods of temporally varying feed quality demonstrated that higher fouling rate (promoted by inline coagulation) resulted in more effective backwash and correspondingly lower progressive rise in post-backwash UF resistance. The study results suggest that real-time UF fouling indicators, based on UF filtration resistance metrics and backwash effectiveness, should be potentially useful for tracking UF performance and thus for deployment of UF feed-back control for optimal performance of UF feed pretreatment.

A machine learning approach to describing the dynamics of ultrafiltration performance in pretreatment of seawater reverse osmosis (RO) feedwater was explored via ensemble back propagation neural network (BPNN) model. The BPNN model was developed with Alopex evolutionary algorithm (AEA) optimization and AdaBoost strategy. The progression of ultrafiltration (UF) membrane resistance during both filtration and backwash, along with backwash efficiency were modeled via the ensemble BPNN-AEA approach relying on 422 days of operational data for an integrated SWRO UF-RO system. Model performance, for UF membrane resistance and backwash efficiency, evaluated over a wide range of operating conditions and coagulant dosing strategies, revealed excellent performance with a forecasting capability even for cases of temporally variable water quality. The performance level attained with the current machine learning modeling approach, which is particularly suited for handling the dynamics of UF operation, should prove useful for (a) determining UF performance deviation from intended baseline performance, (b) forecasting expected UF performance due to anticipated changes in water quality, and (c) providing a basis for model-based control of UF operation.

Silica scaling of RO membranes was evaluated via real-time direct surface imaging demonstrating a capability for detecting the onset of silica scale formation and its evolution. Silica scaling was detected significantly earlier than by traditional flux decline measurements. The observed rate of silica particle nucleation followed classical nucleation theory while the growth of individual silica particles, at the early stages of silica scaling, was governed by diffusional growth. SEM and optical images of the membrane surface suggest that silica scaling occurs through the formation of both primary silica particles and their agglomerates (~1–30 µm), as well as a gel-like silica film embedded with silica particles both of which contribute to permeate flux decline. At low silica saturation index at the membrane surface (SIm≤1.93) silica gel film formation resulted in a smoother and less porous film than at higher silica saturation (SIm≥2.72). At the higher silica saturation levels (SIm=2.72–3.50), silica scaling resulted in larger observed particles as well as rapid permeate flux decline. The silica scale layer thickness was in the range of ~0.1–3.5 µm, with surface roughness being higher by a factor of 2.6–8.3 relative to the native membrane. Results of the present study suggest that there is merit in exploring the application of the present approach for early detection and monitoring of silica scaling in RO plants in support of strategies for silica scale mitigation.

Hydraulic permeability and molecular weight cutoff (MWCO) performance tuning of polysulfone (PSf) ultrafiltration (UF) membrane was attained via surface modification with a tethered layer of poly(acrylic acid) (PAA). Surface nano-structured (SNS) PAA layer was synthesized onto base PSf UF membranes by atmospheric pressure plasma (APP) surface activation followed by graft polymerization (GP) of acrylic acid (AA). Through a systematic study, it was shown that effective SNS-PAA-PSf UF membrane performance tuning was feasible by adjustments of APP and graft polymerization conditions. It was shown, for the first time, that SNS-PAA-PSf membranes can be synthesized with a range of hydraulic permeability (spanning a factor of 1.1–2.6 in magnitude) for a given MWCO, or a range of MWCO (spanning a factor of 1.5–2.3 in magnitude) for a given hydraulic permeability, thereby overcoming the hydraulic permeability-MWCO tradeoff.

The feasibility of a continuous chemically-enhanced seeded precipitation (CCESP) process was evaluated for desupersaturation of primary reverse osmosis (PRO) concentrate generated from RO desalting of inland agricultural drainage (AD) water with high gypsum scaling potential. The CCESP approach, comprised of partial lime treatment (PLT) followed by gypsum seeded precipitation (GSP), was assessed via laboratory and field tests, along with model simulations. PLT effectiveness was confirmed for residual antiscalant removal from the PRO concentrate, which otherwise would suppress gypsum crystallization. GSP was carried out in a fluidized bed crystallizer (FBC) demonstrating the feasibility of continuous PRO concentrate desupersaturation with suitable solids management. FBC operation was stable, with respect to desupersaturation performance, when operating over a sequence of periodic solids purge-only mode with intermittent seeds replenishment. The study suggests that CCESP integration with primary and secondary RO desalting (i.e., PRO-CCESP-SRO) can provide for significant enhancement of product water recovery for inland water of high gypsum scaling propensity. For example, source water of high salinity (14,347 mg/L total dissolved solid) AD water, nearly saturated with respect to gypsum, could be desalted up to a recovery of 88-96% (relative to merely 66% recovery feasible via PRO desalting. Moreover, net salt harvesting of 2.6-3.6 kg per m3 RO concentrate (with concentrate recycle) can be obtained from high recovery desalting of the above PRO concentrate.

Power generation via pressure retarded osmosis (PRO) was explored based on a detailed two dimensional finite-element (2-D-FEM) PRO model. Using the numerical model, an approach is presented for determining the draw and feed crossflow velocities for maximizing peak power generation. The dependence of PRO power generation on channel dimensions, membrane transport parameters were then evaluated, followed by assessing the impact of frictional pressure losses and pumping and energy recovery device (ERD) efficiencies. Illustrative test cases are presented for three different draw/feed streams representing seawater/brackish water (SW/BW), seawater RO-brine/brackish water (SWB/BW), and Dead Sea water/Seawater RO-brine (DSW/SWB). The maximum peak power density attainable via PRO was for DSW/SWB (35.3 W/m2), followed by SWB/BW (7.29 W/m2) and SW/BW (3.53 W/m2) for the case of ideal pumps and ERD. For the optimistic Power generation from DSW/SWB PRO, high efficiency pumps (98%) and ERD (96%) would be required for peak power density to approach ~ 12 W/m2 and 1.6 W/m2 for the cases of DSW/SWB and SWB/BW, respectively, while net positive power generation is not expected for SW/BW. Higher permeability membranes could provide somewhat increased PRO performance; however, frictional pressure loses and less than ideal pumps and ERDs present a barrier for PRO as a viable approach for energy generation.

Real-time self-adaptive approach to in-line UF coagulant dosing was developed and field demonstrated for integrated UF-RO seawater desalination. A novel coagulant dose controller was designed and successfully implemented in a pilot UF-RO seawater desalination plant. The coagulant controller, which tracks the UF resistance during filtration and backwash, adjusts coagulant dose to the UF feed with the objective of reducing the incremental cycle-to-cycle UF post-backwash (PB) resistance change (i.e., Δn). Real-time tracking the above UF resistance metrics, as well as the rate of change of Δn with coagulant dose, enabled the controller to quantify the progression of both irreversible fouling and UF backwash effectiveness. The above information was then utilized by the controller to make the appropriate coagulant adjustment. Field tests of the proposed self-adaptive coagulant dosing approach demonstrated measurable coagulant dose reduction while maintaining robust UF operation even during periods of both mild and severe water quality degradation. The approach to real-time coagulant dose control developed in the present work should be suitable for both seawater and brackish water UF treatment and has the potential of providing both effective UF operation as well as reduction in coagulant use.

Ultrafiltration as a pretreatment for RO feedwater with enhanced UF backwash, which combines continuous with pulse backwash, was investigated in a novel UF-RO process integration. Direct supply of RO concentrate to the UF module served for UF backwash which was further enhanced with pulse backwash generated using bladder-type hydraulic accumulators. Model analysis of the hydraulic accumulator operation, which was validated via a series of field experiments, demonstrated a capability for accumulator charging directly from the RO concentrate stream within a period of 30–40 s. Moreover, pulse backwash over a short period (~5 s) which was added to the continuous UF backwash (directly from the RO brine stream), enabled peak UF backwash flux up to a factor of 4.2–4.6 higher than the normal filtration flux. The above mode of UF operation with multiple consecutive backwash pulses was more effective than with a single pulse, while inline coagulation further increased the UF performance. Relatively long-term field operation (over eight days where) of the UF-RO system with self-adaptive triggering of UF backwash, whereby the number of consecutive pulses increased when a higher membrane fouling resistance was encountered, was highly effective in enabling stable UF operation over a wider range of water quality conditions and without the need for chemical cleaning. These encouraging results suggest that direct UF-RO integration with enhanced pulse UF backwash is an effective approach for dead-end UF filtration without sacrificing water productivity.

Reverse osmosis (RO) polyamide (PA) membrane integrity loss, performance degradation, and alteration of surface properties due to exposure to chlorine were evaluated experimentally via a fluorescent marker (uranine) based method, water permeability and salt flux measurements, and surface characterization via XPS, AFM and contact angle measurements. Membrane exposure to chlorine (4–200 mg/L NaOCl solutions) revealed that although membrane surface roughness increased with chlorine exposure intensity (ppm-h), surface hydrophilicity increased as inferred by the decline (up to 5.2–9.6%) of the surface energy of hydration. Comparative analysis of marker transport for membranes that have undergone chlorine exposure of 125–2000 ppm-h demonstrated that the membrane marker permeability coefficient (B) increased by up to a factor of ~5 relative to the intact membrane. While the severity of membrane integrity loss/performance degradation correlated to a reasonable degree with ppm-h of chlorine exposure, the severity of membrane integrity loss, at the same chlorine ppm-h, was greater for higher exposure concentration. Membrane integrity loss, over the same exposure levels, was quantified by an equivalent cylindrical breach that was in the range of about 14–40 µm, increasing in size with the intensity of chlorine exposure.

The phosphoinositide 3-kinase (PIK3)/v-akt murine thymoma (AKT) oncogene pathway and the RAS/RAF pathway are involved in regulating the signalling of multiple biological processes, including apoptosis, metabolism, cell proliferation, and cell growth. Mutations in the genes within these pathways are frequently found in several tumours. The aim of this study was to investigate the frequency of mutations in the PIK3CA, BRAF, and KRAS genes in cases of malignant salivary gland tumours. Mutational analysis of the PIK3CA, KRAS, and BRAF genes was performed by direct sequencing of material from 21 patients with malignant salivary gland tumours who underwent surgery between 1992 and 2001. No mutations were found in the KRAS exon 2, BRAF exon 15, or PIK3CA exon 9 genes. However, an unpublished mutation of the PIK3CA gene in exon 20 (W1051 stop mutation) was found in one case of adenocarcinoma NOS. The impact of this mutation on the biological behaviour of the tumour has yet to be explored, however the patient with adenocarcinoma NOS harbouring this mutation has survived for over 20 years following surgery despite a high stage at presentation. Further studies with more homogeneous patient cohorts are needed to address whether this mutation reflects a different clinical presentation and may benefit from targeted treatment strategies.

Angular double-pulsed-field gradient (d-PFG) MR methodology is increasingly used to non-invasively obtain pore sizes in opaque chemical and biological systems. In such MR experiments, the angular dependency of the signal at zero mixing time, through modeling, can be used to extract the pore size. In many systems not only the pore sizes but also their directions are of importance. Before applying d-PFG NMR to complex systems, it is of value to challenge the ability of the methodology to extract these microstructural parameters in samples where the ground truth is known. In the present study we explored whether modeling of the signal in angular d-PFG NMR experiments at zero mixing time, can simultaneously provide the size and the direction of tilted compartments with little prior knowledge. We showed that the angular d-PFG MR methodology enables simultaneous extraction of the pore size and the direction of mono-dispersed phantoms and of phantoms where the restricted compartments have different pore sizes. However, we found that in phantoms with two or more pore sizes, only averaged pore sizes were extracted for large azimuthal and polar angles.

A novel design for a reverse osmosis (RO) desalination system directly integrated with an ultrafiltration (UF) pre-treatment unit was developed. The integration involves direct RO feed from the UF filtrate and UF backwash using the RO concentrate. This alignment reduces overall plant footprint, while the use of RO concentrate for UF backwash allows 100% UF recovery and implementation of flexible backwash strategies. The present system design utilizes a control scheme, whereby RO productivity can be prescribed independently of the UF system which self-adjusts to provide the RO system with its required feed flow rate at the specified RO pump inlet pressure. UF backwash, achieved via direct RO concentrate flow from the RO system provided a continuous flow for sequential UF backwash which was additionally integrated with pulse backwash using a hydraulic accumulator. Seawater desalination field studies with a UF–RO pilot system of 12,000 gal/day permeate production capacity successfully demonstrated the advantage of RO concentrate UF backwash that was triggered based on a membrane resistance threshold. The above self-adaptive UF backwash strategy significantly extended the projected UF operation period (by a factor of nine) to the threshold of required chemical cleaning.

Polyamide (PA) thin film composite (TFC) BWRO and SWRO membranes were surface nano-structured (SNS) with tethered hydrophilic poly(acrylic acid) (PAA) layers. BWRO and SWRO membranes having water (Lp) and salt (B) permeability coefficients in the ranges of 2.3–3.4 L m−2 h−1·bar−1 and 0.15–0.54 L m−2 h−1, respectively, were utilized as base membranes onto which tethered PAA layers were synthesized via acrylic acid (AA) graft polymerization (GP), post-membrane surface activation with atmospheric pressure plasma (APP). Both APP surface activation and GP conditions impacted SNS-PAA-PA membrane performance evaluated in terms of the membrane Lp and B parameters. Surface structuring with a tethered PAA layer enabled tuning of membrane performance (in terms of Lp and B) to achieve water/salt selectivity (evaluated as Lp:B ratio) that was significantly higher (by up to 56%) relative to the base PA membranes. Depending on APP surface activation and AA graft polymerization conditions, membranes could be tuned to have essentially the same salt rejection over a range of permeability or a given permeability over a range of salt rejection. It was also shown that a membrane performance could be achieved that overcomes the permselectivity tradeoff.

Filter-Exchange NMR Spectroscopy (FEXSY) is a method for measurement of apparent transmembranal water exchange rates. The experiment is comprised of two co-linear sequential pulsed-field gradient (PFG) blocks, separated by a mixing period in which exchange takes place. The first block remains constant and serves as a diffusion-based filter that removes signal coming from fast-diffusing water. The mixing time and the gradient area (q-value) of the second block are varied on repeated iterations to produce a 2D data set that is analyzed using a bi-compartmental model which assumes that intra- and extra-cellular water are slow and fast diffusing, respectively. Here we suggest a variant of the FEXSY method in which measurements for different mixing times are taken at a constant gradient. This Constant Gradient FEXSY (CG-FEXSY) allows for the determination of the exchange rate by using a smaller 1D data set, so that the same information can be gathered during a considerably shorter scan time. Furthermore, in the limit of high diffusion weighting, such that the extra-cellular water signal is removed while the intra-cellular signal is retained, CG-FEXSY also allows for determination of the intra-cellular mean residence time (MRT). The theoretical results are validated on a living yeast cells sample and on a fixed porcine optic nerve, where the values obtained from the two methods are shown to be in agreement.

The use of 2D finite element CFD model and the common film model (FM) for analysis of FO performance data was examined to assess the merits of conclusions derived from the above approaches regarding characterization of membrane and support layer resistances to water and salt permeation. The FM model leads to estimation of porous layer resistivity (K) that implies tortuosity/porosity ratio that is significantly higher than is physically attainable for typical membrane porous supports. Comparative FO data analysis with the 2D CFD model and FM approximation reveals that the latter approach overestimates (by an order of magnitude and greater) the significance of the permeation resistance of the FO membrane support layer. It is also shown that membrane (water and solute) permeabilities extracted from FO operation in the RO mode (FO/RO) are significantly higher than obtained from direct analysis of FO performance data via detailed 2D CFD modeling. The present analysis suggests that improvements in FO water permeability are more likely to emerge from developing higher permeability membrane skin and improved channel hydrodynamics (to decrease external concentration polarization) rather than from more permeable and thinner membrane support layer as has been asserted in various studies.

The technical feasibility of graywater treatment, via a semi-batch vertical flow wetland (SB-VFW), was evaluated at a single family home for aboveground water reuse. Graywater treatment was achieved to a quality level that was well within the regulatory compliance limits (e.g., with respect to biochemical oxygen demand (BOD), total suspended solids (TSS) and turbidity) for above ground reuse. System performance over the course of a five-month field study demonstrated that the necessary treatment time was typically ∼3 h for a 300 L batch. The SB-VFW operated in a stable manner owing to the use of a coconut soil substitute that has high hydraulic conductivity and also enabled avoidance of clogging due to excess biofilm growth. The latter was made possible through the use of a bio-based laundry (BBL) detergent which had a lower organic content relative to conventional laundry detergents. The system was able to return to normal operation even after detergent shock loads. Results of the present study are encouraging and suggest that residential level graywater treatment is technically feasible and can thus potentially expand the range of possible water reuse applications.

Real-time membrane integrity monitoring is critically needed in order to ensure that reverse osmosis (RO) treatment and desalination processes provide a reliable barrier against the passage of pathogens for potable reuse applications. A pulsed marker membrane integrity monitoring (PM-MIM) method was developed for real-time assessment of RO membrane integrity. The sensitivity of the PM-MIM method was evaluated, using a fluorescent molecular marker, in a plate-and-frame RO (PFRO) membrane system with intact and compromised membranes (induced mechanically and via chemical oxidation). Analysis of the marker permeate concentration–time profiles, in response to a controlled marker feed pulse, allowed unambiguous detection of marker enhanced passage, which was indicative of membrane integrity loss. The PM-MIM approach, which is capable of demonstrating log removal value (LRV) above 4 for a fluorescent molecular marker (smaller in size than pathogens) should be suitable for providing a conservative estimate of pathogens LRV. However, regulatory acceptability of the present real-time PM-MIM approach will undoubtedly require long-term field evaluation in RO plants in order to establish the level of confidence to satisfy regulatory requirements for RO use in potable water reuse applications.

Introduction Magnetic resonance (MR) imaging is a sensitive modality for demonstrating in vivo alterations in brain structure and function after acute organophosphate (OP) poisoning. The goals of this study were to explore early imaging findings in organophosphate-poisoned animals, to assess the efficacy of centrally acting antidotes and to find whether early MR findings can predict post-poisoning cognitive dysfunction. Methods Sprague–Dawley rats were poisoned with the agricultural OP paraoxon and were treated with immediate atropine and obidoxime (ATOX) to reduce acute mortality caused by peripheral inhibition of acetylcholinesterase. Animals were randomly divided into three groups based on the protocol of centrally acting antidotal treatment: group 1 – no central antidotal treatment (n = 10); group 2 – treated with midazolam (MID) at 30 min after poisoning (n = 9), group 3 – treated with a combination of MID and scopolamine (SCOP) at 30 min after poisoning (n = 9) and controls (n = 6). Each animal had a brain MR examination 3 and 24 h after poisoning. Each MR examination included the acquisition of a T2 map and a single-voxel 1H MR spectroscopy (localized on the thalami, to measure total creatine [Cr], N-acetyl-aspartate [NAA] and cholines [Cho] levels). Eleven days after poisoning each animal underwent a Morris water maze to assess hippocampal learning. Eighteen days after poisoning, animals were euthanized, and their brains were dissected, fixed and processed for histology. Results All paraoxon poisoned animals developed generalized convulsions, starting within a few minutes following paraoxon injection. Brain edema was maximal on MR imaging 3 h after poisoning. Both MID and MID + SCOP prevented most of the cortical edema, with equivalent efficacy. Brain metabolic dysfunction, manifested as decreased NAA/Cr, appeared in all poisoned animals as early as 3 h after exposure (1.1 ± 0.07 and 1.42 ± 0.05 in ATOX and control groups, respectively) and remained lower compared to non-poisoned animals even 24 h after poisoning. MID and MID + SCOP prevented much of the 3 h NAA/Cr decrease (1.22 ± 0.05 and 1.32 ± 0.1, respectively). Significant correlations were found between imaging findings (brain edema and spectroscopic changes) and clinical outcomes (poor learning, weight loss and pathological score) with correlation coefficients of 0.4–0.75 (p Conclusions MR imaging is a sensitive modality to explore organophosphate-induced brain damage. Delayed treatment with midazolam with or without scopolamine provides only transient neuroprotection with some advantage in adding scopolamine. Early imaging findings were found to correlate with clinical consequences of organophosphate poisoning and could be potentially used in the future to predict long-term prognosis of poisoned casualties.

Forward osmosis (FO) desalination was investigated via 2-D numerical model of the fully coupled hydrodynamics and mass transfer equations. The model was formulated for a detailed composite channel structure (feed and draw channels, membrane skin layer and porous support) being capable of describing co-current or counter current cross operation where the membrane skin faces the salt feed solution (SFF) or where the membrane skin faces the draw solution (SFD). Simulations based on existing experimental FO data confirmed that FO operation in a counter-current/SFD mode provides slight improvement with respect to water flux, and reduced cross migration of feed and draw solutes relative to the co-current mode of operation. Analysis of existing FO data also revealed the dependence of the intrinsic membrane water permeability and solute transport coefficients on draw solute concentration. Simulation results indicated significant cross membrane migration of feed and draw solutes for long (~1 m) relative to short (~10 cm) FO channels. Moreover, up to an order of magnitude decline of draw solute concentration difference (along the membrane) can be encountered at the draw channel exit region. Simulation results suggest that accurate assessment of FO performance in long channels is critical for full-scale plant design in order to minimize salt leakage, optimize recovery, and setting accurate inlet/outlet conditions to enable simulations of membrane elements in series.

Testing for genetic abnormalities in epithelial growth factor receptor (EGFR), anaplastic lymphoma receptor tyrosine kinase (ALK), and potentially additional genes is a critical tool in the care of advanced NSCLC. There is conflicting evidence for the role of such tests in early NSCLC. We report a single-institute Sequenom testing for a wide range of mutations and their clinical correlations in early-resected NSCLC specimens.Early NSCLC paraffin-embedded, formalin-fixed (FFPE) specimens were collected, DNA extracted, and using Sequenom-based matrix-assisted laser desorption/ionization-time of flight analysis, mutations in 22 oncogenes and tumor suppressor genes were evaluated. Clinical data was collected retrospectively.The technique was found to be feasible. Thirty-six of 96 patients (37.5%) had any genetic abnormality identified, and 8 (8.3%) had 2 or more mutations. Kirsten rat sarcoma viral oncogene homolog (KRAS) and EGFR were the most common genes to appear mutated (15.6%); phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) was the gene to be found most commonly in tumors with co-mutations. Transversions were found mostly in KRAS gene mutations and to be nonprognostic. No difference in the spectrum of mutations was found between squamous-cell and non-squamous-cell lung cancers. Ever-smokers showed a trend for worse prognosis, with a similar spectrum of mutations.Sequenom-based mutation screen is feasible using FFPE samples. More than a third of the patients were found to harbor some genetic abnormality, and 8% were found to have more than a single mutated gene. Wide-range gene screens using large sample depositories are required for further insight into the important genes at play in early NSCLC.

Membrane mineral scaling in semi-batch RO (SBRO) and steady-state RO with partial recycle (SSRO-PR) were investigated experimentally in a spiral-wound pilot system with gypsum as a model scalant. Scaling in SSRO-PR operation, at a given level of solution supersaturation, was compared to SBRO operation at the equivalent time-averaged solution supersaturation, and also for operation at equivalent water recovery. Real-time tracking of mineral scaling revealed that SBRO was more prone to mineral scaling, in terms of both crystals formation rate and scaled membrane surface area, relative to SSRO-PR. The growth rates of crystals in both SBRO and SSRO-PR followed diffusional growth and were similar at the same level of solution supersaturation. However, the crystallization induction time was shorter and rate of crystal formation higher in SBRO relative to SSRO-PR. This behavior was consistent with the higher level of gypsum supersaturation reached in the SBRO filtration period when compared to SSRO-PR at either one of the above operational scenarios. For a given recovery, improved scale mitigation in SBRO via extended flushing to reset the “crystallization induction clock” may be feasible, but the tradeoff is an extended filtration period with a higher level of solution supersaturation.

Semi-batch reverse osmosis (SBRO) desalination was investigated via process modeling and experimentally using a spiral-wound SBRO pilot system. The salinity increase during SBRO filtration necessitates periodic flushing of the excess salinity buildup in the system. Accordingly, concentrate flushing efficacy and its impact on SBRO performance were investigated for multi-cycles of filtration and concentrate flushing. Progressive cycle-to-cycle concentrate salinity rise, due to incomplete (concentrate) flushing, was apparent leading to corresponding SEC increase, but a stable cycle-to-cycle operation was ultimately achieved. Flushing duration longer than the convective residence time improved concentrate flushing. However, for a given recovery, longer flushing required longer filtration. The analysis confirmed that the SEC for an ideal SBRO operation (i.e., complete flushing of excess concentrate salinity) is lower relative to SPRO. However, ideal operation is likely to be a challenge with practical SBRO systems as it would necessitate complete concentrate flushing over the course of one convective residence time. Indeed, experimental evaluation of SBRO demonstrated higher SEC relative to single-pass RO (SPRO). Clearly, experimental quantification of concentrate flushing efficacy is critical for establishing SBRO effectiveness. Irrespective of SEC considerations, both SBRO and SPRO with partial recycle offer the flexibility of desalting operation over a wide recovery range.

The biofouling propensity and cleaning effectiveness were evaluated for a new generation of polyamide thin-film composite (PA-TFC) membranes that are surface nano-structured (SNS) with terminally anchored hydrophilic polymer chains. The SNS-PA-TFC membranes were formed via surface graft polymerization onto the surface of polyamide base membranes previously activated via surface treatment with atmospheric pressure plasma. Poly(methacrylic acid) (PMMA) and polyacrylamide (PAAm) SNS-PA-TFC membranes were synthesized and evaluated with respect to their biofouling resistance using secondary wastewater from a municipal wastewater treatment (MWT) plant. Biofouling resistance and cleaning effectiveness were quantified via flux decline measurements in addition to imaging of the biofouled membranes before and after DI water and chemical (Na 2 ·EDTA) cleaning. Increased biofouling resistance was highest for the PMAA-SNS-PA-TFC membrane being a factor of 4.2 greater than for the commercial membrane of about the same salt rejection used in the MWT plant. Moreover, permeability recovery for the PMAA-SNS-PA-TFC membrane was higher by factors of up to ~1.2 relative to the reference commercial membrane upon cleaning with DI water and more aggressive chemical cleaning at high pressure. The present evaluation of the SNS-PA-TFC membranes suggests that biofouling resistance and cleaning effectiveness of RO membranes can be enhanced via hydrophilic brush layers.

The brains of Long Evans shaker (les) rats, a model of dysmyelination, and their age- matched controls were studied by ex-vivo q-space diffusion imaging (QSI) and diffusion tensor imaging (DTI). The QSI and DTI indices were computed from the same acquisition. The les and the control brains were studied at different stages of maturation and disease progression. The mean displacement, the probability for zero displacement and kurtosis were computed from QSI data while the fractional anisotropy (FA) and the eigenvalues were computed from DTI. It was found that all QSI indices detect the les pathology, at all stages of maturation, while only some of the DTI indices could detect the les pathology. The QSI mean displacement was larger in the les group as compared with their age-matched controls while the probability for zero displacement and the kurtosis were both lower all indicating higher degree of restriction in the control brains. Since all the DTI eigenvalues were higher in the les brains as compared to controls, the less efficient DTI measure for discerning the les pathology was found to be the FA. Clearly, the most sensitive DTI parameter to the les pathology is λ3, i.e., the minimal diffusivity. Since the QSI and DTI data were obtained from the same acquisition, despite the somewhat higher SNR of the QSI data compared to the DTI data, it seems that the higher diagnostic capacity of the QSI data in this experimental model of dysmyelination, originates mainly from the higher diffusing weighting of the QSI data.

In recent years, enormous efforts have been made to translate nanotechnology innovations into medical practice. The main focuses were diagnosis and therapy with recent emphasis on multi-modal imaging. Since in many instance the sites for imaging and therapy are the same it became apparent that targeted magnetic nanoparticles (MNPs), which can be imaged, can also be used as a platform for theranostics applications. MNPs, which are characterized by high surface-to-volume ratios, are not only excellent scaffolds for loading targeting moieties, imaging tags and drugs, but can themselves be used to induce therapeutic effects making them the platform of choice for theranostics applications. In the current assay we will outline some of the recent progress in the synthesis and functionalization of MNPs, as well as their applications in multimodal imaging. The main body of the present essay, however, focuses on recent theranostic applications of such MNPs.

The feasibility of utilizing chemically-enhanced seeded precipitation (CESP) for primary reverse osmosis (PRO) concentrate demineralization was evaluated, via both experimental field tests and process analysis, to assess its potential use in enabling recovery enhancement via secondary RO (SRO) desalting. Field evaluations of batch CESP along with process simulations for desalting of agricultural drainage (AD) water (6700–14,400 mg/L TDS, SIg = ~ 0.9) have suggested that a PRO-CESP-SRO desalting approach is both technically and economically feasible to enable overall desalting recovery of about 83% and, with partial concentrate recycling, of up to 93%. In the CESP process, initial partial lime treatment provides adsorptive removal of residual antiscalant from the PRO concentrate. This enables subsequent concentrate desupersaturation (with respect to the major scaling salt calcium sulfate) to occur via seeded gypsum precipitation, unimpeded by residual antiscalant. The desupersaturated PRO concentrate (~ 34% reduction in SIg from ~ 1.7 to ~ 1.1) can then be further desalted in an SRO step up to the limit that is feasible with antiscalant dosing for scale control. When considering the cost of residual brine disposal, the cost of AD water desalination by PRO-CESP-SRO on the basis of desalted water volume is lower than RO by up to 39%.

The development of data-driven RO plant performance models was demonstrated using the support vector regression model building approach. Models of both steady state and unsteady state plant operation were developed based on a wide range of operational data obtained from a fully automated small spiral-wound RO pilot. Single output variable steady state plant models for flow rates and conductivities of the permeate and retentate streams were of high accuracy, with average absolute relative errors (AARE) of 0.70%–2.46%. Performance of a composite support vector regression (SVR) based model (for both streams) for flow rates and conductivities was of comparable accuracy to the single output variable models (AARE of 0.71%–2.54%). The temporal change in conductivity, as a result of transient system operation (induced by perturbation of either system pressure or flow rate), was described by SVR model, which utilizes a time forecasting approach, with performance level of less than 1% AARE for forecasting periods of 2 s to 3.5 min. The high level of performance obtained with the present modeling approach suggests that short-term performance forecasting models that are based on plant data, could be useful for advanced RO plant control algorithms, fault tolerant control and process optimization.

The technical feasibility of operating a spiral-wound RO plant in a cyclic mode of feed-flow reversal (FFR) was evaluated for brackish water desalting under conditions of high mineral scaling propensity. Scale-free and continuous permeate productivity was demonstrated, with calcium sulfate as the model scalant, in an automated spiral-wound RO pilot system in which FFR was triggered by scale detection in an external membrane monitor (MeMo). Real-time detection of mineral scaling in an external RO MeMo cell, receiving its feed from the concentrate of the RO plant tail element, enabled cyclic FFR operation in a self-adaptive mode accomplished by feed-back RO plant control in which permeate productivity was maintained. Membrane permeability was restored after each FFR cycle even with the initiation of membrane cleaning (i.e., via FFR) after a measurable level of scale formation in the MeMo and spiral-wound RO pilot. FFR cycle periods varied in length given the stochastic nature of crystal nucleation on the membranes in both the RO plant and in the MeMo RO cell. Scale-free FFR operation was demonstrated, without anticalant addition, with the RO plant operating (up to 81% recovery) such that the gypsum saturation index was up to 3.45 at the membrane surface of the tail element.

The influence of a pre-existing biofilm on RO membrane mineral scaling was evaluated using gypsum as a model scalant. The biofilm was established using microfiltered secondary treated wastewater effluent on-site in a wastewater treatment facility. Mineral scaling was then monitored via direct visual observation of crystal growth on the membrane surface in a transparent plate-and-frame RO cell. SEM imaging of the membrane surface and sectioned biofilm revealed gypsum crystals within the biofilm matrix, including the protrusion of crystal rods from within the biofilm. Both mineral scale surface coverage and crystal number density were greater in the presence of the biofilm. Moreover, individual mineral crystal growth rate within the biofilm was significantly higher relative to growth in the absence of a biofilm. Analyses of crystal growth and nucleation rates, within the biofilm and in its absence, suggest concentration polarization enhancement within the biofilm. The present study suggests that mineral scaling may not be restricted to tail elements in RO plants, but could also occur in lead elements where biofilms can enhance concentration polarization. Therefore, understanding of the coupling of biofouling and mineral scaling may be of particular significance to the operation and design of RO plants in water reuse applications.

An experimental study was carried out to demonstrate and quantify the feasibility of antiscalant (AS) removal from brackish water RO concentrate of high gypsum scaling propensity via lime treatment prior to seeded gypsum precipitation. Based on studies with model solutions, it was shown that sufficient AS removal (up to ∼90%) from RO concentrate is feasible via a lime treatment step (at a dose significantly lower than that required for conventional lime softening) to enable effective subsequent seeded gypsum precipitation. This two-step chemically-enhanced seeded precipitation (CESP) treatment of primary RO concentrate is suitable as an intermediate concentrate demineralization (ICD) stage for high recovery desalting employing secondary RO desalination. Analysis of gypsum precipitation and lime treatment kinetic data suggests that, after adequate CaCO 3 precipitation has been induced for effective AS scavenging, CaSO 4 desupersaturation can be achieved via seeded gypsum precipitation without retardation due to seed poisoning by AS. Also, the lime dose required to prevent seed poisoning during subsequent gypsum desupersaturation via seeded gypsum precipitation can be adequately assessed with a precipitation kinetics model that considers AS seed poisoning based on a Langmuir adsorption isotherm. The degree of AS removal after lime treatment increased linearly with the logarithm of the single lime dose additions. Staged lime dosing (i.e., multiple lime additions), however, removed a higher degree of AS relative to an equivalent single lime dose addition since a higher driving force for CaCO 3 precipitation could be maintained over the course of the lime treatment period.

The feasibility of removing calcium scale precursor ions from reverse osmosis (RO) concentrate by accelerated seeded precipitation (ASP) was investigated with the goal of increasing product water recovery and minimizing the volume of concentrate disposal from inland municipal wastewater desalination plants. Three seed materials were tested in laboratory trials — calcium carbonate, calcium sulfate and calcium phosphate. Calcium carbonate and calcium sulfate seed were not effective. The addition of calcium phosphate seed particles at 20 g L− 1 or phosphate ion in stoichiometric excess of the calcium concentration (250 mg L− 1 Ca = 6.25 mM Ca2+, 650 mg L− 1 HPO42− = 6.7 mM) decreased the calcium content in the RO concentrate to 10 mg L− 1. Evaluation of the accelerated seeded precipitation process using in-situ generated calcium phosphate seed at the pilot scale was performed on a 25 kL day− 1 pilot plant consisting of dissolved air flotation, ultrafiltration and reverse osmosis. The treated concentrate was filtered by a ceramic filtration system. Preliminary cost analyses indicate that high recovery RO using calcium phosphate precipitation can only be justified in inland situations where restrictions on concentrate disposal drive smaller evaporation pond storage volumes to offset the higher chemical and energy running costs.

Double-Pulsed-Field-Gradient (d-PFG) MR is emerging as a powerful new means for obtaining unique microstructural information in opaque porous systems that cannot be obtained by conventional single-PFG (s-PFG) methods. The angular d-PFG MR methodology is particularly important since it can utilize the effects of microscopic anisotropy (μA) and compartment shape anisotropy (csA) in the E(ψ) profile at the different t(m) regimes to provide detailed information on compartment size and eccentricity. An underlying assumption is that the PFGs that are imparted to weigh diffusion are the only gradients present; however, in realistic systems and especially where there are randomly oriented anisotropic pores, susceptibility effects may induce strong internal gradients. In this study, the effects of such internal gradients on E(ψ) plots obtained from angular d-PFG MR and on microstructural information that can be obtained from s-PFG and d-PFG MR were investigated. First, it was found that internal gradients induce a bias in the s-PFG MR results, thus creating an anisotropy that is not related to microstructure, termed apparent-Susceptibility-Induced-Anisotropy (aSIA). We then show that aSIA effects are also manifest in different ways in the angular d-PFG MR experiment in controlled phantoms and in realistic systems such as quartz sand, emulsions, and biological systems. The effects of aSIA in some cases completely masked the effects of μA and csA; however, we subsequently show that by introducing bipolar gradients to the d-PFG MR (bp-d-PFG), the effects of aSIA can be largely suppressed, restoring the E(ψ) plots that are expected from the theory along with the microstructural information that it conveys. We conclude that when specimens are characterized by strong internal gradients, the novel information on μA and csA that is manifest in the E(ψ) plots can indeed be inferred when bp-d-PFG MR is used, i.e. when bipolar gradients are applied.

Summary The phosphoinositide 3-kinase (PI3K)/v-akt murine thymoma (AKT) viral oncogene pathway is involved in regulating the signaling of multiple biological processes such as apoptosis, metabolism, cell proliferation, and cell growth. Mutations in the genes associated with the PI3K/AKT pathway including PI3K , AKT , RAS and PTEN , are infrequently found within head and neck squamous cell carcinoma and more specifically are rarely reported in oral squamous cell carcinoma (OSCC) cases. We aimed to investigate the frequency of mutations in AKT1 , PTEN , PIK3CA , and RAS ( K-RAS , N-RAS , H-RAS ) genes in 37 cases of oral squamous cell carcinoma (OSCC). Mutational analysis of PTEN , RAS , PIK3CA and AKT genes was performed using chip-based matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry and by direct sequencing. The only gene mutated in our series was the PIK3CA . Missense mutations of the PIK3CA gene were found in 4 of our cases (10.8%); no correlation has been found with oral location, stage and survival. The absence of mutations in AKT1 , PTEN , and RAS genes in the present study is in accordance with previous studies confirming that these genes are rarely mutated in OSCC. Our data confirm that PIK3CA is important to OSCC tumorigenesis and can contribute to oncogene activation of the PIK3CA / AKT pathway in OSCC. The knowledge of the PIK3CA’s involvement in OSCC is important because a specific kinase inhibitor could be considered as a future therapeutic option for OSCC patients with PIK3CA mutations.

The mineral scaling propensity of aromatic polyamide membrane surfaces was evaluated for surfaces ranging in roughness from about 1 to 94 nm, surface feature heights ranging from a few nanometers to as high as 400–450 nm and average peak separation of ∼140 nm to 2 μm. The polyamide surfaces were interfacially polymerized onto quartz crystal microbalance (QCM) sensors and silicon wafer substrates which were previously structured with a polyelectrolyte film formed by a layer-by-layer self-assembly method. Mineral scaling was quantified via QCM measurements of the time evolution of surface crystallization along with SEM and AFM surface characterization. Crystal surface mass density and rate of surface crystallization increased with increasing surface roughness. However, surface scaling propensity was also significantly impacted by the details of surface topography revealing fewer but larger crystals on rough surfaces that possessed large features with large separation distances. It is hypothesized that the separation distance between features and feature heights (dictating the geometry of surface “valleys”), for a given surface roughness, could affect the availability of surface nucleation sites as well as constrain growth of crystals within surface valleys.

An approach to real-time analysis of mineral scale formation on reverse osmosis (RO) membranes was developed using an ex-situ direct observation membrane monitor (MeMo). The purpose of such monitoring is to signal the onset of mineral scaling and provide quantitative information in order to appropriately initiate system cleaning/scale dissolution. The above is enabled by setting the MeMo operating conditions (cross flow velocity and transmembrane pressure) to closely match the conditions in the monitored membrane plant (e.g., in the tail RO element) in order to mimic the surface scaling processes taking place inside the monitored RO plant element. Mineral scale in the MeMo system is monitored by comparison of consecutive images of the membrane surface for the purpose of determining the evolution of the fractional coverage by mineral salt crystals and the corresponding crystal count in the monitored region. Through online image analysis, once crystal growth is determined to be above a prescribed threshold, one can then initiate any number of cleaning protocols. Through early detection of membrane scaling (i.e., before permeate flux decline is observed), enabled by the present monitoring approach, the system operator can prevent irreversible membrane damage and loss of system productivity.

This study evaluated intermediate chemical demineralization (ICD) as a technique for overcoming mineral salt solubility limits that constrain the water recovery of reverse osmosis (RO) desalting. An empirical approach was developed to determine theoretical cation removal set points for ICD based on predetermined process design and operation guidelines to facilitate increasing the overall water recovery of Colorado River water desalting from 85% (i.e., in the primary RO unit) to 95% via a secondary RO (SRO) unit. Additionally, the study evaluated whether microfiltration (MF) or dual-media filtration (DMF) could serve as the filtration step prior to the secondary reverse osmosis (SRO) unit. The model suggested ranges for ICD influent total-carbonate-to-calcium ratios and ICD effluent pH to simultaneously mitigate barium sulfate, calcium sulfate, and silica scaling. MF was preferred over DMF as the filtration step prior to SRO based on significantly lower filter effluent turbidity and silt density indices. The overall PRO-ICD-SRO system operated for over 550 h at 95% total RO water recovery without evidence of scaling of the terminal RO elements, validating the cation removal set points developed through the ICD model and demonstrating the utility of ICD.

Surface crystallization of calcium sulfate dihydrate (gypsum) on a series of polymeric surfaces was studied using a quartz microbalance system. Polyelectrolyte multilayer films (positively and negatively charged surfaces) were formed on the quartz crystal microbalance (QCM) sensors utilizing a layer-by-layer spin-assembly method. The kinetics of gypsum surface crystallization was quantified in terms of the evolution of gypsum mineral scale on the different surfaces. For comparison mineral scaling was also evaluated on silica and polyamide surfaces. For surfaces of the same charge polarity (+/-), the mass density of gypsum scale was lower (PSS < PAA, PEI < PAH) for smoother surfaces. The extent of surface mineral scaling (quantified in terms of both mass density and aerial coverage) were the combined result of the rate of nucleation and crystal growth kinetics. Although aerial scale coverage correlated with the crystal mass density, the crystal number density did not correlate with the extent of surface scaling. Surface crystal size, morphology and crystal number density varied significantly at similar roughness levels, suggesting that surface chemical functionality may also affect surface crystallization. The present results suggest that there is merit in exploring methods for mitigation of mineral scaling on polymeric surfaces via alteration of surface both surface topography and chemistry. In this regards, an expanded systematic study is needed in order to quantitatively clarify the interplay between the above two factors in controlling surface crystallization.

Double pulsed-field gradient (d-PFG) MRI can provide quantitative maps of microstructural quantities and features within porous media and tissues. We propose and describe a novel MRI phantom, consisting of wafers of highly ordered glass capillary arrays (GCA), and its use to validate and calibrate a d-PFG MRI method to measure and map the local pore diameter. Specifically, we employ d-PFG Spin-Echo Filtered MRI in conjunction with a recently introduced theoretical framework, to estimate a mean pore diameter in each voxel within the imaging volume. This simulation scheme accounts for all diffusion and imaging gradients within the diffusion weighted MRI (DWI) sequence, and admits the violation of the short gradient pulse approximation. These diameter maps agree well with pore sizes measured using both optical microscopy and single PFG diffusion diffraction NMR spectroscopy using the same phantom. Pixel-by-pixel analysis shows that the local pore diameter can be mapped precisely and accurately within a specimen using d-PFG MRI.

A two-step chemically-enhanced seeded precipitation (CESP) process was demonstrated for accelerated desupersaturation of antiscalant-containing, gypsum-supersaturated model solutions, which mimicked reverse osmosis (RO) concentrate from RO desalting of agricultural drainage water of high mineral scaling propensity. In the CESP process, CaCO3 precipitation is first induced via lime dosing for antiscalant scavenging, followed by subsequent CaSO4 precipitation via gypsum seeding for concentrate desupersaturation. It was demonstrated that lime-precipitated CaCO3 particles were able to scavenge generic and commercial polycarboxylic-acid antiscalants, thereby facilitating subsequent CaSO4 precipitation to progress with minimal retardation. The study demonstrated via a series of batch CESP cycles that gypsum particle recycling can sustain CaSO4 precipitation, suggesting that a continuous CESP process could be feasible. Process analysis suggests that CESP can be significantly less chemical-intensive than conventional precipitation softening and, with its integration as an intermediate RO concentrate demineralization process, can enable desalination water recovery enhancement via secondary RO desalting. For the present case of gypsum-saturated RO feed water, enhancement of overall water recovery from 63% up to 87% or higher appears to be feasible. The study suggests that there is merit for developing a continuous CESP process for high recovery RO desalting of brackish water of high gypsum scaling propensity.

This work focuses on the design and implementation of an optimization-based control system on an experimental reverse osmosis (RO) membrane water desalination process in order to facilitate system operation at an energy optimal condition. A dynamic nonlinear lumped-parameter model for the RO process is derived using first principles and the model parameters are computed from experimental data to minimize the error between model predictions and actual system response. This model, along with several equations for reverse osmosis system energy analysis, are combined to form the basis for the design of a nonlinear optimization-based control system. The proposed control system is implemented on UCLA's experimental RO system and its energy optimization capabilities are evaluated.

An experimental method was developed for quantifying mineral scale nucleation and growth on RO membranes enabling comparison of the effectiveness of antiscalants in retarding mineral scale formation. Mineral scale growth and inhibition was evaluated, for calcium sulfate dihydrate (gypsum) as a model scalant, from direct visual observations of crystal growth on the membrane surface in a plate-and-frame RO cell. Comparison of membrane scaling with and without the use of antiscalants was carried out based on RO scaling tests conducted under identical operating conditions with respect to the initial flux and crossflow velocity, at identical initial concentration fields within the RO membrane channel and at the membrane surface. The range of gypsum saturation index (SIg) at the membrane surface was 1.3–2.3 enabling determination of gypsum scaling for the above SIg range from a single RO scaling test, given direct observation of crystal nucleation and growth on the membrane surface. The present work demonstrates that it is possible to distinguish antiscalants modes of scale inhibition and corresponding scale suppression effectiveness, over a reasonable range of solution supersaturation. The current approach introduces antiscalant crystal nucleation and growth retardation factors that can aid in the development, selection and dose optimization of antiscalants for use in RO desalination.

Various mixing operations between the feed, retentate and permeate streams are studied in this work to determine their effectiveness in decreasing the specific energy consumption (SEC) of single-stage (single-pass), two-pass and two-stage reverse osmosis (RO) processes operated at the limit of the thermodynamic restriction. The results show that in a single-stage RO process, partial retentate recycling to the feed stream does not change the SEC, while partial permeate recycling to the feed stream increases the SEC if targeting the same overall water recovery. Energy optimization of two-pass membrane desalination, with second-pass retentate recycling to the first-pass feed stream and operated at the limit imposed by the thermodynamic restriction, revealed the existence of a critical water recovery. When desalting is accomplished at recoveries above the critical water recovery, two-pass desalination with recycling is always less efficient than single-pass desalination. When desalting is accomplished at recoveries below the critical water recovery, an operational sub-domain exists in which the SEC for a two-pass process with recycling can be lower than for a single-pass counterpart, when the latter is not operated at its globally optimal state. For the two-stage RO process, diverting part of the raw feed to the second stage, in order to dilute the feed to the second-stage RO, does not decrease the minimal achievable SEC of a two-stage RO process. The various mixing approaches, while may provide certain operational or system design advantages (e.g., with respect to achieving target salt rejection for certain solutes or flux balancing), do not provide an advantage from an energy usage perspective.