Anaerobic-aerobic biofilm-based digestion of chemical contaminants of emerging concern (CEC) and pathogen indicator organisms in synthetic wastewater.

The efficacy of biofilm based anaerobic-aerobic treatment to reduce caffeine, carbamazepine, and three estrogens (Estrone (E1), 17ß-estradiol (E2), and 17α-ethynylestradiol (EE2)), as well as E. coli (CN-13) and F+ specific coliphage (MS2), from synthetic wastewater was investigated. Results showed no observable reduction of carbamazepine by either anaerobic or aerobic biofilms over a dosing period of 51-days followed by an additional 23 days of observation. Caffeine, by contrast, was reduced by 11.09% in the upflow anaerobic packed bed biofilm reactor (UAnPBBR) and by 91.90% in the aerobic trickling filter biofilm reactor (TF). Estrone (E1) and 17ß-estradiol (E2) showed minimal reduction in the UAnPBBR but 99.67% reduction in the TF, while EE2 was reduced 1.62% in the AnPBBR and 20.36% in the TF. On average, a 3-log reduction of E. coli (CN-13) and a 1-log reduction of F+ specific coliphage (MS2) concentration was observed across the overall reactor system.

Kinetic Measurements for Enzyme Immobilization.

Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of this enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten were advancing their work by studying the kinetics of an enzyme saccharase which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis and ever since the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, and selectivity towards nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adapted to the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V max, K M) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

TOMOGRAPHIC RELATIONSHIPS BETWEEN RETINAL NEOVASCULARIZATION AND THE POSTERIOR VITREOUS IN PROLIFERATIVE DIABETIC RETINOPATHY.

PURPOSE: To describe anatomical relationships of retinal neovascular complexes (NVCs) and the posterior vitreous in proliferative diabetic retinopathy using spectral domain optical coherence tomography. METHODS: Cross-sectional study. Neovascular complexes were imaged using spectral domain optical coherence tomography in 51 eyes of 37 patients. The relationship of NVCs to the posterior vitreous cortex and posterior vitreous spaces, such as the premacular bursa, prevascular vitreous fissures, and perimacular cisterns, was analyzed. RESULTS: In the 77 NVCs evaluated, 61 (79%) had grown along the outer surface of the posterior hyaloid face, and vitreoschisis was present in 37 (48%). The "wolf's jaw" configuration was present in 9% and resulted from NVC arising from the arcades and proliferating along the posterior hyaloid face. By contrast, NVCs that invaded the bursa originated from smaller venous tributaries more distant from the arcades. The premacular bursa and prevascular vitreous fissure/perimacular cistern were invaded infrequently, respectively, in 15% and 38% (P = 0.137). CONCLUSION: Tomographic analysis of diabetic NVCs showed that most NVCs arise and grow along the posterior hyaloid face and that vitreoschisis is more prevalent than what has been found in ultrasound studies. The wolf's jaw configuration does not seem to result from the invasion of the bursa, as previously suggested.

Bio-oil extraction of Jatropha curcas with ionic liquid co-solvent: Fate of biomass protein.

The fate of oil-seed biomass protein has been tracked through all steps of a multi-phase extraction process using an ionic liquid based co-solvent system previously demonstrated to extract bio-oil and phorbol esters and to recover fermentable sugars from Jatropha oil seed. These analyses, however, did not address the fate of biomass protein. This work demonstrated that the majority of protein (∼86%) tracked with the biomass with the balance lost to co-solvent (∼12%) and methanol (∼2%) washes. A significant portion of the ionic liquid remained with the treated biomass and required aggressive methanol washes to recover. A system analysis showed a net-positive energy balance and thus the potential of this system to produce both bio-oil and protein-rich toxin-free biomass. While these results further support Jatropha as an oil seed crop, the additional costs of solvent recovery will need to be addressed if commercialization is to be realized.

Life cycle assessment comparison of activated sludge, trickling filter, and high-rate anaerobic-aerobic digestion (HRAAD).

This paper conducts a comparative assessment of the environmental impacts of three methods of treating primary clarifier effluent in wastewater treatment plants (WWTPs) through life cycle assessment methodology. The three technologies, activated sludge (AS), high rate anaerobic-aerobic digestion (HRAAD), and trickling filter (TF), were assessed for treatment of wastewater possessing average values of biochemical oxygen demand and total suspended solids of 90 mg L(-1) and 70 mg L(-1), respectively. The operational requirements to process the municipal wastewater to effluent that meets USEPA regulations have been calculated. The data for the AS system were collected from the East Honolulu WWTP (Hawaii, USA) while data for the HRAAD system were collected from a demonstration-scale system at the same plant. The data for the TF system were estimated from published literature. Two different assessment methods have been used in this study: IMPACT 2002+ and TRACI 2. The results show that TF had the smallest environmental impacts and that AS had the largest, while HRAAD was in between the two but with much reduced impacts compared with AS. Additionally, the study shows that lower sludge production is the greatest advantage of HRAAD for reducing environmental impacts compared with AS.

Volume-Rendering Optical Coherence Tomography Angiography of Macular Telangiectasia Type 2.

PURPOSE: To evaluate the vascular structure of eyes with macular telangiectasia type 2 (MacTel2) using volume-rendered optical coherence tomography angiography (OCTA). DESIGN: Retrospective cross-sectional study. PARTICIPANTS: A total of 14 consecutive patients (20 eyes) with MacTel2 who had a signal strength score ≥55 and could maintain fixation during the scan process. METHODS: The eyes were scanned using optical coherence tomography with split-spectrum amplitude decorrelation techniques to derive flow information. Data were extracted and used to create volume-rendered images of the retinal vasculature that could be rotated about 3 different axes for evaluation. MAIN OUTCOME MEASURES: Descriptive appraisal of the vascular abnormalities associated with MacTel2. RESULTS: Vessels posterior to the outer boundary of the deep retinal plexus were secondary to retinal thinning, vascular invasion, or a combination of both. These vessels had the same shape and distribution as the late staining seen during conventional fluorescein angiography. Lateral contraction in the temporal macula in 5 eyes created an appearance of vessels radiating from a central locus, which was the site of a right angle vein. Loss of macular tissue as part of the disease process led to a central amalgamation of the inner vascular plexus and the deep vascular plexus, which appeared to be in a state of decline. Subretinal neovascularization originated from the retinal circulation but involved not only the subretinal space but also could infiltrate the remaining, thinned, retina. CONCLUSIONS: Volume rendering of OCTA information preserves the 3-dimensional relationships among retinal vascular layers and provides opportunities to visualize retinal vascular abnormalities in unprecedented detail. The retinal vascular leakage and invasion in MacTel2 may arise as a consequence of loss of control with depletion of Müller cells and exposure of the remaining retinal vessels to the more hypoxic environment near the inner segments of the photoreceptors.

Biodegradation of fat, oil and grease (FOG) deposits under various redox conditions relevant to sewer environment.

Fat, oil and, grease (FOG) deposits are one primary cause of sanitary sewer overflows (SSOs). While numerous studies have examined the formation of FOG deposits in sewer pipes, little is known about their biodegradation under sewer environments. In this study, FOG deposit biodegradation potential was determined by studying the biodegradation of calcium palmitate in laboratory under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions. Over 110 days of observation, calcium palmitate was biodegraded to CO2 under aerobic and nitrate-reducing conditions. An approximate 13 times higher CO2 production rate was observed under aerobic condition than under nitrate-reducing condition. Under sulfate-reducing condition, calcium palmitate was recalcitrant to biodegradation as evidenced by small reduction in sulfate. No evidence was found to support calcium palmitate degradation under methanogenic condition in the simulated sewer environment. Dominant microbial populations in the aerobic and nitrate-reducing microcosms were identified by Illumina seqeuncing, which may contain the capability to degrade calcium palmitate under both aerobic and nitrate-reducing conditions. Further study on these populations and their functional genes could shed more light on this microbial process and eventually help develop engineering solutions for SSOs control in the future.

Retinal vascular layers imaged by fluorescein angiography and optical coherence tomography angiography.

IMPORTANCE: The retinal vasculature is involved in many ocular diseases that cause visual loss. Although fluorescein angiography is the criterion standard for evaluating the retina vasculature, it has risks of adverse effects and known defects in imaging all the layers of the retinal vasculature. Optical coherence tomography (OCT) angiography can image vessels based on flow characteristics and may provide improved information. OBJECTIVE: To investigate the ability of OCT angiography to image the vascular layers within the retina compared with conventional fluorescein angiography. DESIGN, SETTING, AND PARTICIPANTS: In this study, performed from March 14, 2014, through June 24, 2014, a total of 5 consecutive, overlapping B-scan OCT angiography images composed of 216 A-scans were obtained at 216 discrete positions within a region of interest, typically a 2 × 2-mm area of the retina. The flow imaging was based on split-spectrum amplitude decorrelation angiography (SSADA), which can dissect layers of vessels in the retina. These distinct layers were compared with the fluorescein angiograms in 12 healthy eyes from patients at a private practice retina clinic to evaluate the ability to visualize the radial peripapillary capillary network. The proportion of the inner vs outer retinal vascular layers was estimated by 3 masked readers and compared with conventional fluorescein angiograms of the same eyes. MAIN OUTCOMES AND MEASURES: Outcome measures were visualization of the radial peripapillary capillary network in the fluorescein and SSADA scans and the proportion of the inner retinal vascular plexus vs the outer retinal capillary plexus as seen in SSADA scans that would match the fluorescein angiogram. RESULTS: In none of the 12 eyes could the radial peripapillary capillary network be visualized completely around the nerve head by fluorescein angiography, whereas the network was readily visualized in the SSADA scans. The fluorescein angiograms were matched, with a mean proportion of the inner vascular plexus being 95.3% (95% CI, 92.2%-97.8%) vs 4.7% (95% CI, 2.6%-5.7%) for the outer capillary plexus from the SSADA scans. CONCLUSIONS AND RELEVANCE: Fluorescein angiography does not image the radial peripapillary or the deep capillary networks well. However, OCT angiography can image all layers of the retinal vasculature without dye injection. Therefore, OCT angiography, and the findings generated, have the potential to affect clinical evaluation of the retina in healthy patients and patients with disease.

Retinal vascular layers in macular telangiectasia type 2 imaged by optical coherence tomographic angiography.

IMPORTANCE: Macular telangiectasia type 2 (MacTel 2) is a rare disease in which abnormalities of the retinal vasculature play a key role. The vascular abnormalities are typically evaluated using fluorescein angiography, a modality with known defects in imaging the deeper layers of the retinal vasculature. Angiography based on optical coherence tomography can image vessels based on flow characteristics without dye injection and may provide improved information concerning the pathophysiology of MacTel 2. OBJECTIVE: To investigate MacTel 2 using optical coherence tomographic angiography. DESIGN, SETTING, AND PARTICIPANTS: Fourteen eyes of 7 patients with MacTel 2 were analyzed in a community-based retina practice. The flow imaging was based on split-spectrum amplitude decorrelation angiography, which can dissect layers of vessels in the retina. The inner retinal vascular plexus, the outer plexus, and deeper vascular invasion into the outer and subretinal spaces were optically dissected in en face images based on flow. MAIN OUTCOMES AND MEASURES: Visualization and qualitative evaluation of the vascular layers of the retina as they may be affected by MacTel 2, both in terms of depth and topographic characteristics. RESULTS: A consistent set of retinal vascular changes were seen in the eyes with MacTel 2. There was some loss of capillary density in the inner retinal vascular plexus but many more prominent alterations in the deep retinal vascular plexus. In milder forms of the disease, the deep plexus showed dilation and telangiectasis and, in more advanced cases, thinning and loss. The remaining vessels were elongated and widely spaced capillary segments. Invasion by new vessels into the outer and subretinal spaces occurred subjacent to the regions showing greatest flow imaging abnormalities in the inner and deep retinal vascular layers. CONCLUSIONS AND RELEVANCE: As evidenced by the patients in this study, important retinal vascular changes in MacTel 2 occur in the deep capillary plexus of the retina, a layer poorly visualized by fluorescein angiography and, to a lesser extent, in the inner vascular plexus. The proliferation of vessels in the outer and subretinal spaces may be in part compensatory for poor retinal perfusion by established vascular layers in the retina.

The spectrum of superficial and deep capillary ischemia in retinal artery occlusion.

PURPOSE: To describe the spectrum of retinal capillary ischemia, including superficial and deep capillary ischemia, as identified with spectral-domain optical coherence tomography (SD OCT), that occurs in retinal arterial occlusive disease. DESIGN: Retrospective observational case series. METHODS: Clinical charts, color fundus photography, red-free fundus photography, fluorescein angiography, near-infrared reflectance, and SD OCT imaging in 40 eyes of 35 patients with retinal arterial occlusive disease were studied in both the acute and chronic phases in multicenter clinical practices. SD OCT imaging analysis was employed to characterize the presence of superficial and deep capillary ischemia in each eye. RESULTS: Of the 40 eyes, 15 eyes had central retinal artery occlusion (CRAO), 22 eyes had branch retinal artery occlusion (BRAO), and 3 eyes had cilioretinal artery occlusion. During the acute phase, SD OCT showed the following 3 distinct patterns, related to retinal ischemia occurring at varying levels within the retina: (1) thickening and hyperreflectivity of the inner retinal layers, including the nerve fiber and ganglion cell layers owing to ischemia of the superficial capillary plexus; (2) a hyperreflective band at the level of the inner nuclear layer, termed "paracentral acute middle maculopathy," representing ischemia of the intermediate and deep retinal capillary plexuses (deep capillary ischemia); and (3) diffuse thickening and hyperreflectivity of both the inner and middle retinal layers, which represented both superficial and deep capillary ischemia. Of all eyes, 31 (78%) had both superficial and deep lesions. The remaining 9 eyes (22%) had isolated deep capillary ischemia producing paracentral acute middle maculopathy with sparing of the superficial capillary plexus and a normal fluorescein angiographic appearance. As the lesions evolved into the chronic phase over the ensuing 3 months, the resultant thinning and atrophy reflected the retinal layers affected during the acute phase. CONCLUSION: SD OCT imaging reveals the spectrum of capillary ischemia in retinal artery occlusive disease showing variable involvement of the superficial and intermediate/deep capillary plexuses. Isolated deep capillary ischemia manifested as paracentral acute middle maculopathy on SD OCT and may be seen in some eyes with retinal arterial circulation compromise despite complete absence of perfusion abnormalities on fluorescein angiography.

Corecovery of lipids and fermentable sugars from Rhodosporidium toruloides using ionic liquid cosolvents: application of recycle to batch fermentation.

This work evaluates the ability of an ionic liquid-methanol cosolvent system to extract lipids and recycle fermentable sugars recovered from oil-bearing Rhodosporidium toruloides grown in batch culture on defined media using glucose and xylose as carbon sources. Growth on the recycled mixed carbon substrate was successful with glucose consumed before xylose and overall cell mass to lipid yields (YP/X ) between 57% and 61% (w/w relative to whole dried cell mass) achieved. Enzymatic hydrolysis of the delipified carbohydrate fraction recovered approximately 9%-11% (w/w) of the whole dried cell mass as fermentable sugars, which were successfully recycled as carbon sources without further purification. In total, up to 70% (w/w) of the whole dried cell mass was recovered as lipids and fermentable sugars and the substrate to lipid yields (YP/S ) was increased from 0.12 to 0.16 g lipid/g carbohydrate consumed, highlighting the promise of this approach to process lipid bearing cell biomass.

Towards a hybrid anaerobic digester-microbial fuel cell integrated energy recovery system: an overview of the development of an electrogenic biofilm.

An electrogenic biofilm was developed on a macroporous chitosan-carbon nanotube (CHIT-CNT) electrode under constant poised potential (-0.25V versus Ag/AgCl reference electrode) and flow through conditions utilizing the effluent of an anaerobic digester as both the inoculant and substrate for the electrogenic biofilm. After 125 days of inoculation the bioelectrode demonstrated an open circuit potential of -0.62V and a current density of 9.43µAcm(-3) (at -0.25V). Scanning electron microscopy images indicate thorough surface coverage of the biofilm with a high density of bacterial nanowires physically connecting bacteria to bacteria and bacteria to carbon nanotube (electrode surface) suggesting the nanowires are electrically conductive. DGGE was used to identify the major bacterial and archaeal populations.

Controlled deposition of structured polymer films: chemical and rheological factors in chitosan film formation.

The technique of "spread coating" has been used to create thin films from solutions of deacetylated and butyl-modified chitosan polymer, and the effect of deposition rate on film thickness has been characterized. Results show that films of controlled thickness can be reproducibly produced and that hydrophobic modification of the polymer can extend the range over which a linear response between film thickness and deposition rate is achieved. Viscometry and fluorescence spectroscopy were also employed to characterize the micellar characteristics of solutions of both deacetylated and butyl-modified chitosan polymer. Although both deacetylated and butyl-modified chitosan solutions were found to have inter- and intramolecular interactions, as well as hydrophobic domains able to incorporate fluorophores, deacetylated chitosan was found to be more interconnected via intermolecular interactions at higher concentrations. These results are important as having the ability to understand how the introduction of hydrophobic modification, a technique shown to introduce solution-based micelle structure and micellar aggregates that support enzyme immobilization, affects film thickness and morphology of spread coated thin films will aid the long-term development and deployment of chitosan-based biofuel cell electrodes.

Sustained increased intraocular pressure related to intravitreal antivascular endothelial growth factor therapy for neovascular age-related macular degeneration.

PURPOSE: To describe a series of previously normotensive eyes experiencing sustained elevated intraocular pressure (IOP) associated with long-term intravitreal antivascular endothelial growth factor (VEGF) therapy for neovascular age-related macular degeneration (AMD). PATIENTS AND METHODS: Clinical data were reviewed for 25 eyes of 23 patients with neovascular AMD who had increased IOP while receiving interval doses of intravitreal ranibizumab and/or bevacizumab. All eyes had tolerated multiple anti-VEGF injections in the past without IOP elevations. RESULTS: After a mean of 20.0 anti-VEGF injections (range, 8-40 injections), the mean IOP was 29.8 mm Hg (range, 22-58 mm Hg), compared with a baseline of 16.9 mm Hg (range, 14-21 mm Hg). The mean highest IOP while receiving intravitreal anti-VEGF therapy was 35.8 mm Hg (range, 23-58 mm Hg). Overall, 23 of 25 cases required IOP management. In the remaining 2 cases, anti-VEGF dosing was switched from regular interval dosing to an optical coherence tomography-guided variable regimen, with subsequent improvement in IOP without antiglaucoma treatment. CONCLUSIONS: Serial injections of anti-VEGF agents may lead to persistent IOP elevations that require glaucoma therapy. The clinician should recognize this phenomenon, as it can occur even if the patient has tolerated multiple prior injections without IOP elevation. Further exploration of the relationship between anti-VEGF therapy and IOP is needed.

Fabrication of macroporous chitosan scaffolds doped with carbon nanotubes and their characterization in microbial fuel cell operation.

Chitosan (CHIT) scaffolds doped with multi-walled carbon nanotubes (CNT) were fabricated and evaluated for their utility as a microbial fuel cell (MFC) anodic material. High resolution microscopy verified the ability of Shewanella oneidensis MR-1 to directly colonize CHIT-CNT scaffolds. Cross-linking agents 1-ethyl-3-[3-dimethylaminopropyl] carbodimide hydrochloride (EDC), glutaraldehyde and glyoxal were independently studied for their ability to strengthen the CHIT-CNT matrix without disrupting the final pore structure. 2.5 vol% glyoxal was found to be the optimal cross-linker in terms of porosity (BET surface area=30.2 m(2) g(-1)) and structural stability. Glyoxyl and EDC cross-linked CHIT-CNT scaffolds were then studied for their ability to transfer electrons to underlying glassy carbon. Results showed an open circuit cell voltage of 600 mV and a maximum power density of 4.75 W/m(3) at a current density of 16 A/m(3) was achieved in non stirred batch mode, which compares well with published data using carbon felt electrodes where a power density of 3.5 W/m(3) at a current density of 7 A/m(3) have been reported. Additionally, CHIT-CNT scaffolds were impregnated into carbon felt electrodes and these results suggest that CHIT-CNT scaffolds can be successfully integrated with multiple support materials to create hybrid electrode materials. Further, preliminary tests indicate that the integrated scaffolds offer a robust macroporous electrode material that can be used in flow-through configurations.

Outer retinal abnormalities in acute macular neuroretinopathy.

PURPOSE: To investigate the spectral-domain optical coherence tomography findings in four cases of acute macular neuroretinopathy and identify features that may differentiate acute macular neuroretinopathy from similar conditions in the acute zonal occult outer retinopathy complex. METHODS: Patients with acute macular neuroretinopathy underwent complete periodic examinations, including ophthalmoscopy, color photography and autofluorescence photography, visual field testing, and spectral-domain optical coherence tomography. Abnormalities as seen by multimodal imaging were documented and evaluated during follow-up. RESULTS: The average age of the 4 patients was 32 years (range, 28-34 years), and 2 had bilateral involvement. The follow-up ranged from 1 month to 5 months. In each patient, dark lobular areas seen by ophthalmoscopy corresponded to the measured visual field defect and what appeared to be a regional loss of outer segments of the photoreceptors. The outer segment defect resolved in two patients and improved in the other two during follow-up. All patients showed a colocalizing regional thinning of the outer nuclear layer, which did not change during the follow-up period. There were no associated abnormalities in the fundus appearance. CONCLUSION: Acute macular neuroretinopathy causes reddish brown patches that are because of outer retinal damage as documented by spectral-domain optical coherence tomography. Unlike other entities in the acute zonal occult outer retinopathy complex, acute macular neuroretinopathy has no other synchronic ophthalmoscopically visible fundus abnormalities. These lesions may resolve over time, with restoration of the outermost retinal architecture, but persistent thinning of the overlying outer nuclear layer remained.

Kinetic measurements for enzyme immobilization.

Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of the enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten had advanced this work by studying the kinetics of the enzyme saccharase, which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis, and ever since, the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, selectivity toward nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adopted for the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V(max), K(M)) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review, enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.