Effective toluene removal from aqueous solutions using fast pyrolysis-derived activated carbon from agricultural and forest residues: Isotherms and kinetics study.

In this study, the production and characterization of activated carbons (ACs) from agricultural and forest residue using physical activation are discussed. Biomass-based biochars produced during fast pyrolysis process is introduced as alternative precursors to produce AC and the integrated process for the co-production of porous adsorbent materials from biochar via the fast pyrolysis process is suggested. Moderate surface areas and good adsorption capacities were obtained from switchgrass (SWG) and pine tops (PT) based AC. The surface areas were 959 and 714 m2/g for SWG- and PT-based AC, respectively. The adsorption capacities using toluene as pollutant for two model systems of 180 and 300 ppm were measured and ranged between 441-711 and 432-716 mg/g for SWG-based and PT-based AC, respectively. The nitrogen adsorptive behavior, Lagergren pseudo-second-order kinetic (PSOK) model and kinetics isotherms studies describe a heterogeneous porous system, including a mesoporous fraction with the existence of a multilayer adsorption performance. The presence of micropores and mesopores in SWG- and PT-based AC suggests potential commercial applications for using pyrolytic biochars for AC production.

Production of single-component cellulose-based hydrogel and its utilization as adsorbent for aqueous contaminants.

The growing concern for the environment has resulted in renewed interest in bio-based resources. This study aims to produce a hydrogel adsorbent from cellulose and examine its adsorption performance. In pursuit of this goal, we report a simple one-pot synthesis of cellulose acetate sulfate (CAS), followed by the formation of CAS hydrogels and their subsequent adsorption performances. The CAS includes both hydrophilic and hydrophobic functional groups, enable the formation of a single-component hydrogel through intermolecular interactions in deionized water. The thermal reversibility of CAS hydrogels makes them easily processable into various shapes. The durability of the CAS hydrogel adsorbents can be improved by introducing divalent cations (e.g., Ca2+), which create ionically crosslinked hydrogels. The ionically a crosslinked CAS hydrogel adsorbent exhibits a maximum adsorption capacity of 245 mg/g for methylene blue (MB) at 23 °C and a pH of 7. The adsorption behavior of MB on the CAS hydrogel follows both the pseudo-second-order model and the Langmuir adsorption isotherm model. Furthermore, the CAS hydrogel adsorbent maintains a 70 % removal ratio after five cycles. The simplicity of synthesis and hydrogel formation opens up new possibilities for producing and utilizing cellulose-based hydrogels as adsorbents for aqueous contaminants.

A novel functional role for the classic CNS neurotransmitters, GABA, glycine, and glutamate, in the kidney: potent and opposing regulators of the renal vasculature.

The presence of a renal GABA/glutamate system has previously been described; however, its functional significance in the kidney remains undefined. We hypothesized, given its extensive presence in the kidney, that activation of this GABA/glutamate system would elicit a vasoactive response from the renal microvessels. The functional data here demonstrate, for the first time, that activation of endogenous GABA and glutamate receptors in the kidney significantly alters microvessel diameter with important implications for influencing renal blood flow. Renal blood flow is regulated in both the renal cortical and medullary microcirculatory beds via diverse signaling pathways. GABA- and glutamate-mediated effects on renal capillaries are strikingly similar to those central to the regulation of central nervous system capillaries, that is, exposing renal tissue to physiological concentrations of GABA, glutamate, and glycine led to alterations in the way that contractile cells, pericytes, and smooth muscle cells, regulate microvessel diameter in the kidney. Since dysregulated renal blood flow is linked to chronic renal disease, alterations in the renal GABA/glutamate system, possibly through prescription drugs, could significantly impact long-term kidney function.NEW & NOTEWORTHY Functional data here offer novel insight into the vasoactive activity of the renal GABA/glutamate system. These data show that activation of endogenous GABA and glutamate receptors in the kidney significantly alters microvessel diameter. Furthermore, the results show that these antiepileptic drugs are as potentially challenging to the kidney as nonsteroidal anti-inflammatory drugs.

At-Line Sampling and Characterization of Pyrolytic Vapors from Biomass Feedstock Blends Using SPME-GC/MS-PCA: Influence of Char on Fast Pyrolysis.

Solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) analysis was used for the at-line sampling of pyrolytic vapors produced during the fast pyrolysis of biomass. The pure and binary blends of switchgrass (SWG) and pine harvest residues (PT6) were used as biomass feedstocks. Sequential SPME sampling allowed for monitoring of changes in the pyrolysis vapors as char accumulated in the fluid bed. The relative concentration and composition of the pyrolysis vapors desorbed from the SPME fibers were investigated using GC-MS, and the resulting chromatograms were analyzed using principal component analysis (PCA) to compare the composition of the pyrolysis vapors over the course of the pyrolysis run. The chemical compositions of both carbohydrate and lignin fragments varied as the char builds up in the reactor bed. Fragments derived from cellulose and hemicelluloses included anhydrosugars, furans, and light-oxygenated compounds. Lignin fragments included methoxyphenols, phenolic ketones, aldehydes, and low-molecular-weight aromatics. The composition of the carbohydrate fragments changed more than those of the lignin fragments as the char built up in the fluid bed. This combination of SPME-GC/MS-PCA was a novel, easy, and effective method for measuring the composition and changes in the composition of pyrolysis vapors during the fast pyrolysis process. This work also highlighted the effect of char build-up on the composition of the overall pyrolysis vapors.

Dynamic life-cycle carbon analysis for fast pyrolysis biofuel produced from pine residues: implications of carbon temporal effects.

BACKGROUND: Woody biomass has been considered as a promising feedstock for biofuel production via thermochemical conversion technologies such as fast pyrolysis. Extensive Life Cycle Assessment studies have been completed to evaluate the carbon intensity of woody biomass-derived biofuels via fast pyrolysis. However, most studies assumed that woody biomass such as forest residues is a carbon-neutral feedstock like annual crops, despite a distinctive timeframe it takes to grow woody biomass. Besides, few studies have investigated the impacts of forest dynamics and the temporal effects of carbon on the overall carbon intensity of woody-derived biofuels. This study addressed such gaps by developing a life-cycle carbon analysis framework integrating dynamic modeling for forest and biorefinery systems with a time-based discounted Global Warming Potential (GWP) method developed in this work. The framework analyzed dynamic carbon and energy flows of a supply chain for biofuel production from pine residues via fast pyrolysis. RESULTS: The mean carbon intensity of biofuel given by Monte Carlo simulation across three pine growth cases ranges from 40.8-41.2 g CO2e MJ-1 (static method) to 51.0-65.2 g CO2e MJ-1 (using the time-based discounted GWP method) when combusting biochar for energy recovery. If biochar is utilized as soil amendment, the carbon intensity reduces to 19.0-19.7 g CO2e MJ-1 (static method) and 29.6-43.4 g CO2e MJ-1 in the time-based method. Forest growth and yields (controlled by forest management strategies) show more significant impacts on biofuel carbon intensity when the temporal effect of carbon is taken into consideration. Variation in forest operations and management (e.g., energy consumption of thinning and harvesting), on the other hand, has little impact on the biofuel carbon intensity. CONCLUSIONS: The carbon temporal effect, particularly the time lag of carbon sequestration during pine growth, has direct impacts on the carbon intensity of biofuels produced from pine residues from a stand-level pine growth and management point of view. The carbon implications are also significantly impacted by the assumptions of biochar end-of-life cases and forest management strategies.

Techno-economic analysis of producing xylo-oligosaccharides and cellulose microfibers from lignocellulosic biomass.

This study assesses the economic performance of a biorefinery producing xylo-oligosaccharides (XOS) from miscanthus by autohydrolysis and purification based on a rigorous model developed in ASPEN Plus. Varied biorefinery capacities (50-250 oven dry metric ton (ODMT)/day) and three XOS content levels (80%, 90%, 95%) are analyzed. The XOS minimum selling price (XOS MSP) is varied between $3,430-$7,500, $4,030-$8,970, and $4,840-$10,640 per metric ton (MT) for 80%, 90%, and 95% content, respectively. The results show that increasing biorefinery capacity can significantly reduce the XOS MSP and higher purity leads to higher XOS MSP due to less yield, and higher capital and operating costs. This study also explores another system configuration to produce high-value byproducts, cellulose microfiber, by utilizing the cellulose to produce microfiber instead of combusting for energy recovery. The XOS MSP of cellulose microfiber case is $2,460-$7,040/MT and thus exhibits potential economic benefits over the other cases.

Design strategies, properties and applications of cellulose nanomaterials-enhanced products with residual, technical or nanoscale lignin-A review.

With the increasing demand for greener alternatives to fossil-derived products, research on cellulose nanomaterials (CNMs) has rapidly expanded. The combination of nanoscale properties and sustainable attributes makes CNMs an asset in the quest for a sustainable society. However, challenges such as the hydrophilic nature of CNMs, their low compatibility with non-polar matrices and modest thermal stability, slow the development of end-uses. Combination of CNMs with amphiphilic lignin can improve the thermal stability, enhance the compatibility with non-polar matrices and, additionally, endow CNMs with new functionalities e.g., UV shielding or antioxidative properties. This article comprehensively reviews the different design strategies and their influence on properties and applications of CNMs containing lignin in various forms; either as residual lignin, added technical lignin, or nanoscale particles. The review focuses especially on the synergy created between CNMs and lignin, paving the way for new production routes and use of CNM/lignin materials in high-performance applications.

Long-Tailed Macaques (Macaca fascicularis) in Urban Landscapes: Gastrointestinal Parasitism and Barriers for Healthy Coexistence in Northeast Thailand.

Gastrointestinal parasites have diverse life cycles that can involve people, animals, and the environment (e.g., water and soil), demonstrating the utility of One Health frameworks in characterizing infection risk. Kosumpee Forest Park (Thailand) is home to a dense population of long-tailed macaques (Macaca fascicularis) that frequently interact with tourists and local residents. Our study investigated the presence of zoonotic parasites, and barriers to healthy coexistence by conducting stool analysis on macaques (N = 102) and people (N = 115), and by examining risk factors for infection with a household questionnaire (N = 95). Overall, 44% of macaques and 12% of people were infected with one or more gastrointestinal helminths, including Strongyloides spp., Ascaris spp., and Trichuris sp. An adults-only generalized linear mixed model identified three factors significantly associated with human infection: household size, occupational exposure, and contact with macaque feces at home. Participants identified both advantages and disadvantages to living in close contact with macaques, suggesting that interventions to improve human and animal health in Kosumpee Forest Park would be welcome.

Structure and properties of [(4,6-tBu2C6H2O)2Se]2An(THF)2, An = U, Np, and their reaction with p-benzoquinone.

The synthesis and characterization of U(iv) and Np(iv) selenium bis(phenolate) complexes are reported. The reaction of two equivalents of the U(iv) complex with p-benzoquinone results in the formation of a U(v)-U(v) species with a bridging reduced quinone. This represents a rare example of high-valent uranium chemistry as well as a rare example of a neptunium aryloxide complex.

Steam torrefaction of Eucalyptus globulus for producing black pellets: A pilot-scale experience.

Steam torrefaction of Eucalyptus globulus was performed at temperatures between 245°C and 265°C in a 100kg/h pilot plant. Torrefied biomass was then pelletized in a 300kg/h unit and the pellets were subject to durability, density and combustion tests. The structural changes measured with FTIR were studied along with the combustion behavior of the materials. Compositional analysis showed that increasing the torrefaction temperature reduced both hemicellulose fraction and overall mass yield (MY). Furthermore, there was a linear relationship between the energy yield (EY) and mass yield (EY=[1.04-0.9(1-MY)]) for these samples. The ignition and comprehensive indexes confirmed that the stability of the torrefied biomass in a combustion environment was higher than for untreated biomass. Finally, pellets showed high durability (98%), and had an energy density (13-14GJ/m3), which is comparable to low-rank coals.

Altered urothelial ATP signaling in a major subset of human overactive bladder patients with pyuria.

Overactive Bladder (OAB) is an idiopathic condition, characterized by urgency, urinary frequency, and urgency incontinence, in the absence of routinely traceable urinary infection. We have described microscopic pyuria (≥10 wbc/µl) in patients suffering from the worst symptoms. It is established that inflammation is associated with increased ATP release from epithelial cells, and extracellular ATP originating from the urothelium following increased hydrostatic pressure is a mediator of bladder sensation. Here, using bladder biopsy samples, we have investigated urothelial ATP signaling in OAB patients with microscopic pyuria. Basal, but not stretch-evoked, release of ATP was significantly greater from the urothelium of OAB patients with pyuria than from non-OAB patients or OAB patients without pyuria (<10 wbc/µl). Basal ATP release from the urothelium of OAB patients with pyuria was inhibited by the P2 receptor antagonist suramin and abolished by the hemichannel blocker carbenoxolone, which differed from stretch-activated ATP release. Altered P2 receptor expression was evident in the urothelium from pyuric OAB patients. Furthermore, intracellular bacteria were visualized in shed urothelial cells from ∼80% of OAB patients with pyuria. These data suggest that increased ATP release from the urothelium, involving bacterial colonization, may play a role in the heightened symptoms associated with pyuric OAB patients.

Lignin-Based Thermoplastic Materials.

Lignin-based thermoplastic materials have attracted increasing interest as sustainable, cost-effective, and biodegradable alternatives for petroleum-based thermoplastics. As an amorphous thermoplastic material, lignin has a relatively high glass-transition temperature and also undergoes radical-induced self-condensation at high temperatures, which limits its thermal processability. Additionally, lignin-based materials are usually brittle and exhibit poor mechanical properties. To improve the thermoplasticity and mechanical properties of technical lignin, polymers or plasticizers are usually integrated with lignin by blending or chemical modification. This Review attempts to cover the reported approaches towards the development of lignin-based thermoplastic materials on the basis of published information. Approaches reviewed include plasticization, blending with miscible polymers, and chemical modifications by esterification, etherification, polymer grafting, and copolymerization. Those lignin-based thermoplastic materials are expected to show applications as engineering plastics, polymeric foams, thermoplastic elastomers, and carbon-fiber precursors.

Donor preoperative oxygen delivery and post-extubation hypoxia impact donation after circulatory death hypoxic cholangiopathy.

AIM: To evaluate donation after circulatory death (DCD) orthotopic liver transplant outcomes [hypoxic cholangiopathy (HC) and patient/graft survival] and donor risk-conditions. METHODS: From 2003-2013, 45 DCD donor transplants were performed. Predonation physiologic data from UNOS DonorNet included preoperative systolic and diastolic blood pressure, heart rate, pH, SpO2, PaO2, FiO2, and hemoglobin. Mean arterial blood pressure was computed from the systolic and diastolic blood pressures. Donor preoperative arterial O2 content was computed as [hemoglobin (gm/dL) × 1.37 (mL O2/gm) × SpO2%) + (0.003 × PaO2)]. The amount of preoperative donor red blood cell transfusions given and vasopressor use during the intensive care unit stay were documented. Donors who were transfused ≥ 1 unit of red-cells or received ≥ 2 vasopressors in the preoperative period were categorized as the red-cell/multi-pressor group. Following withdrawal of life support, donor ischemia time was computed as the number-of-minutes from onset of diastolic blood pressure < 60 mmHg until aortic cross clamping. Donor hypoxemia time was the number-of-minutes from onset of pulse oximetry < 80% until clamping. Donor hypoxia score was (ischemia time + hypoxemia time) ÷ donor preoperative hemoglobin. RESULTS: The 1, 3, and 5 year graft and patient survival rates were 83%, 77%, 60%; and 92%, 84%, and 72%, respectively. HC occurred in 49% with 16% requiring retransplant. HC occurred in donors with increased age (33.0 ± 10.6 years vs 25.6 ± 8.4 years, P = 0.014), less preoperative multiple vasopressors or red-cell transfusion (9.5% vs 54.6%, P = 0.002), lower preoperative hemoglobin (10.7 ± 2.2 gm/dL vs 12.3 ± 2.1 gm/dL, P = 0.017), lower preoperative arterial oxygen content (14.8 ± 2.8 mL O2/100 mL blood vs 16.8 ± 3.3 mL O2/100 mL blood, P = 0.049), greater hypoxia score >2.0 (69.6% vs 25.0%, P = 0.006), and increased preoperative mean arterial pressure (92.7 ± 16.2 mmHg vs 83.8 ± 18.5 mmHg, P = 0.10). HC was independently associated with age, multi-pressor/red-cell transfusion status, arterial oxygen content, hypoxia score, and mean arterial pressure (r(2) = 0.6197). The transplantation rate was greater for the later period with more liberal donor selection [era 2 (7.1/year)], compared to our early experience [era 1 (2.5/year)]. HC occurred in 63.0% during era 2 and in 29.4% during era 1 (P = 0.03). Era 2 donors had longer times for extubation-to-asystole (14.4 ± 4.7 m vs 9.3 ± 4.5 m, P = 0.001), ischemia (13.9 ± 5.9 m vs 9.7 ± 5.6 m, P = 0.03), and hypoxemia (16.0 ± 5.1 m vs 11.1 ± 6.7 m, P = 0.013) and a higher hypoxia score > 2.0 rate (73.1% vs 28.6%, P = 0.006). CONCLUSION: Easily measured donor indices, including a hypoxia score, provide an objective measure of DCD liver transplantation risk for recipient HC. Donor selection criteria influence HC rates.

Wood Extractives Promote Cellulase Activity on Cellulosic Substrates.

Deposition of hydrophobic wood extractives and representative model compounds, on the surface of cellulose prior to enzymatic hydrolysis was found to either enhance or inhibit the action of cellulase enzymes. The effect of these compounds was correlated with their chemical structure, which may in part explain the differential effects observed between softwood and hardwood extractives. Specifically, the addition of sterol, enhanced enzymatic hydrolysis of microcrystalline cellulose by 54%, whereas the addition of a triglyceride could inhibit the hydrolysis by 49%. The effects of the different extractives' could be explained by considering their Hansen solubility parameters. The amphiphilic and/or hydrophobic character of model extractives was found to be the variable that affected the deposition of extractives on cellulose surfaces and the eventual adsorption of cellulolytic enzymes on it. The observed beneficial effects of extractives are likely related to a reduction in the irreversible binding of the enzymes on the cellulose surface.

Determination of molecular weight distributions in native and pretreated wood.

The analysis of native wood components by size-exclusion chromatography (SEC) is challenging. Isolation, derivatization and solubilization of wood polymers is required prior to the analysis. The present approach allowed the determination of molecular weight distributions of the carbohydrates and of lignin in native and processed woods, without preparative component isolation steps. For the first time a component selective SEC analysis of sawdust preparations was made possible by the combination of two selective derivatization methods, namely; ionic liquid assisted benzoylation of the carbohydrate fraction and acetobromination of the lignin in acetic acid media. These were optimized for wood samples. The developed method was thus used to examine changes in softwood samples after degradative mechanical and/or chemical treatments, such as ball milling, steam explosion, green liquor pulping, and chemical oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The methodology can also be applied to examine changes in molecular weight and lignin-carbohydrate linkages that occur during wood-based biorefinery operations, such as pretreatments, and enzymatic saccharification.

NIR and Py-mbms coupled with multivariate data analysis as a high-throughput biomass characterization technique: a review.

Optimizing the use of lignocellulosic biomass as the feedstock for renewable energy production is currently being developed globally. Biomass is a complex mixture of cellulose, hemicelluloses, lignins, extractives, and proteins; as well as inorganic salts. Cell wall compositional analysis for biomass characterization is laborious and time consuming. In order to characterize biomass fast and efficiently, several high through-put technologies have been successfully developed. Among them, near infrared spectroscopy (NIR) and pyrolysis-molecular beam mass spectrometry (Py-mbms) are complementary tools and capable of evaluating a large number of raw or modified biomass in a short period of time. NIR shows vibrations associated with specific chemical structures whereas Py-mbms depicts the full range of fragments from the decomposition of biomass. Both NIR vibrations and Py-mbms peaks are assigned to possible chemical functional groups and molecular structures. They provide complementary information of chemical insight of biomaterials. However, it is challenging to interpret the informative results because of the large amount of overlapping bands or decomposition fragments contained in the spectra. In order to improve the efficiency of data analysis, multivariate analysis tools have been adapted to define the significant correlations among data variables, so that the large number of bands/peaks could be replaced by a small number of reconstructed variables representing original variation. Reconstructed data variables are used for sample comparison (principal component analysis) and for building regression models (partial least square regression) between biomass chemical structures and properties of interests. In this review, the important biomass chemical structures measured by NIR and Py-mbms are summarized. The advantages and disadvantages of conventional data analysis methods and multivariate data analysis methods are introduced, compared and evaluated. This review aims to serve as a guide for choosing the most effective data analysis methods for NIR and Py-mbms characterization of biomass.

Inhibition of native 5-HT3 receptor-evoked contractions in guinea pig and mouse ileum by antimalarial drugs.

Quinine, chloroquine and mefloquine are commonly used to treat malaria, however, with associated gastrointestinal (GI) side-effects. These drugs act as antagonists at recombinant 5-HT3 receptors and modulate gut peristalsis. These gastrointestinal side effects may be the result of antagonism at intestinal 5-HT3 receptors. Ileum from male C57BL/6 mice and guinea pigs was mounted longitudinally in organ baths. The concentration-response curves for 5-HT and the selective 5-HT3 agonist 2-Me-5-HT were obtained with 5-HT (pEC50 = 7.57 ± 0.33, 12) more potent (P = 0.004) than 2-Me-5-HT (pEC50 = 5.45 ± 0.58, n = 5) in mouse ileum. There was no difference in potency of 5-HT (pEC50 = 5.42 ± 0.15, n = 8) and 2-Me-5-HT (pIC50 = 5.01 ± 0.55, n = 11) in guinea pig ileum (P > 0.05). Quinine, chloroquine or mefloquine was applied for 10 min and inhibitions prior to submaximal agonist application. In mouse ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 4.9 ± 0.17, n = 7; 4.76 ± 0.14, n = 5; 6.21 ± 0.2, n = 4, correspondingly) with mefloquine most potent (P < 0.05). Quinine, chloroquine and mefloquine antagonised 2-me-5-HT-induced contractions (pIC50 = 6.35 ± 0.11, n = 8; 4.64 ± 0.2, n = 7; 5.11 ± 0.22, n = 6, correspondingly) with quinine most potent (P < 0.05). In guinea-pig ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 5.02 ± 0.15, n = 6; 4.54 ± 0.1, n = 7; 5.32 ± 0.13, n = 5) and 2-me-5-HT-induced contractions (pIC50 = 4.62 ± 0.25, n = 5; 4.56 ± 0.14, n = 6; 5.67 ± 0.12, n = 4) with chloroquine least potent against 5-HT and mefloquine most potent against 2-me-5-HT (P < 0.05). These results support previous studies identifying anti-malarial drugs as antagonists at recombinant 5-HT3 receptors and may also demonstrate the ability of these drugs to influence native 5-HT3 receptor-evoked contractile responses which may account for their associated GI side-effects.

Urinary ATP and visualization of intracellular bacteria: a superior diagnostic marker for recurrent UTI in renal transplant recipients?

Renal transplant recipients (RTR) are highly susceptible to urinary tract infections (UTIs) with over 50% of patients having at least one UTI within the first year. Yet it is generally acknowledged that there is considerable insensitivity and inaccuracy in routine urinalysis when screening for UTIs. Thus a large number of transplant patients with genuine urine infections may go undiagnosed and develop chronic recalcitrant infections, which can be associated with graft loss and morbidity. Given a recent study demonstrating ATP is released by urothelial cells in response to bacteria exposure, possibly acting at metabotropic P2Y receptors mediating a proinflammatory response, we have investigated alternative, and possibly more appropriate, urinalysis techniques in a cohort of RTRs. Mid-stream urine (MSU) samples were collected from 53 outpatient RTRs. Conventional leukocyte esterase and nitrite dipstick tests, and microscopic pyuria counts (in 1 µl), ATP concentration measurements, and identification of intracellular bacteria in shed urothelial cells, were performed on fresh unspun samples and compared to 'gold-standard' bacterial culture results. Of the 53 RTRs, 22% were deemed to have a UTI by 'gold-standard' conventional bacteria culture, whereas 87%, 8% and 4% showed evidence of UTIs according to leukocyte esterase dipstick, nitrite dipstick, and a combination of both dipsticks, respectively. Intracellular bacteria were visualized in shed urothelial cells of 44% of RTRs, however only 1 of the 23 RTRs (44%) was deemed to have a UTI by conventional bacteria culture. A significant association of the 'gold-standard' test with urinary ATP concentration combined with visualization of intracellular bacteria in shed urothelial cells was determined using the Fisher's exact test. It is apparent that standard bedside tests for UTIs give variable results and that seemingly quiescent bacteria in urothelial cells are very common in RTRs and may represent a focus of subclinical infection. Furthermore, our results suggest urinary ATP concentration combined with detection of intracellular bacteria in shed urinary epithelial cells may be a sensitive means by which to detect 'occult' infection in RTRs.

Bicomponent lignocellulose thin films to study the role of surface lignin in cellulolytic reactions.

Ultrathin bicomponent films of cellulose and lignin derivatives were deposited on silica supports by spin coating, and after conversion into the respective polymer precursor, they were used as a model system to investigate interfacial phenomena relevant to lignocellulose biocatalysis. Film morphology, surface chemical composition, and wettability were determined by atomic force microscopy, X-ray photoelectron spectroscopy, and water contact angle, respectively. Phase separation of cellulose and lignin produced structures that resembled the cell wall of fibers and were used to monitor enzyme binding and cellulolytic reactions via quartz crystal microgravimetry. The rate and extent of hydrolysis was quantified by using kinetic models that indicated the role of the surface lignin domains in enzyme inhibition. Hydrophobic interactions between cellulases and the substrates and their critical role on irreversible adsorption were elucidated by using acetylated lignin films with different degrees of substitution. Overall, it is concluded that sensors based on the proposed ultrathin films of lignocellulose can facilitate a better understanding of the complex events that occur during bioconversion of cellulosic biomass.