Publications by authors named "James W Lee"

The transmembrane-electrostatically localized protons (TELP) theory can serve as a unified framework to explain experimental observations and elucidate bioenergetic systems including both delocalized and localized protonic coupling. With the TELP model as a unified framework, it is now better explained how the bacteriorhodopsin-purple membrane-ATPase system functions. The bacteriorhodopsin pumping of protons across the membrane results in the formation of TELP around the halobacterial extracellular membrane surface that is perfectly positioned to drive ATP synthase for the synthesis of ATP from ADP and Pi.

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The transmembrane-electrostatically localized protons (TELP) theory can serve as a unified framework to explain experimental observations and elucidate bioenergetic systems including both delocalized and localized protonic coupling. With the TELP model as a unified framework, we can now better explain: the experimental results of Pohl's group (Zhang et al. 2012) as an effect of transient "excess protons" that can temporally form because of the difference between the fast protonic conduction in liquid water through the "hops and turns" mechanism and the relatively slow diffusion of chloride anions.

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Superior mesenteric artery (SMA) syndrome is a rare, unusual cause of proximal intestinal obstruction. It is characterized by compression of the third part of the duodenum secondary to narrowing of the anatomical space between the SMA and the aorta due to a loss of the intervening mesenteric fat pad. This case highlights the challenge in obtaining a pre-operative radiological diagnosis in an extreme case of gastric outlet obstruction in SMA syndrome, fatally complicated by ACS and bilateral lower limb ischemia.

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Background: Biochar ozonization was previously shown to dramatically increase its cation exchange capacity, thus improving its nutrient retention capacity. The potential soil application of ozonized biochar warrants the need for a toxicity study that investigates its effects on microorganisms.

Results: In the study presented here, we found that the filtrates collected from ozonized pine 400 biochar and ozonized rogue biochar did not have any inhibitory effects on the soil environmental bacteria Pseudomonas putida, even at high dissolved organic carbon (DOC) concentrations of 300 ppm.

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Transmembrane electrostatically localized protons (TELP) theory has been recently recognized as an important addition over the classic Mitchell's chemiosmosis; thus, the proton motive force (pmf) is largely contributed from TELP near the membrane. As an extension to this theory, a novel phenomenon of mitochondrial thermotrophic function is now characterized by biophysical analyses of pmf in relation to the TELP concentrations at the liquid-membrane interface. This leads to the conclusion that the oxidative phosphorylation also utilizes environmental heat energy associated with the thermal kinetic energy (kT) of TELP in mitochondria.

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Through the research presented herein, it is quite clear that there are two thermodynamically distinct types (A and B) of energetic processes naturally occurring on Earth. Type A, such as glycolysis and the tricarboxylic acid cycle, apparently follows the second law well; Type B, as exemplified by the thermotrophic function with transmembrane electrostatically localized protons presented here, does not necessarily have to be constrained by the second law, owing to its special asymmetric function. This study now, for the first time, numerically shows that transmembrane electrostatic proton localization (Type-B process) represents a negative entropy event with a local protonic entropy change (ΔSL) in a range from -95 to -110 J/K∙mol.

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With the employment of the transmembrane electrostatic proton localization theory with a new membrane potential equation, neural resting and action potential is now much better understood as the voltage contributed by the localized protons/cations at a neural liquid- membrane interface. Accordingly, the neural resting/action potential is essentially a protonic/cationic membrane capacitor behavior. It is now understood with a newly formulated action potential equation: when action potential is <0 (negative number), the localized protons/cations charge density at the liquid-membrane interface along the periplasmic side is >0 (positive number); when the action potential is >0, the concentration of the localized protons and localized nonproton cations is <0, indicating a "depolarization" state.

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This study employing the latest theory on transmembrane electrostatic proton localization has now, for the first time, consistently elucidated a decades-longstanding bioenergetic conundrum in alkalophilic bacteria and more importantly discovered an entirely new feature: isothermal environmental heat utilization by electrostatically localized protons at the liquid-membrane interface. It was surprisingly revealed that the protonic motive force (equivalent to Gibbs free energy) from the isothermal environmental heat energy utilization through the electrostatically localized protons is not constrained by the overall energetics of the redox-driven proton pump system because of the following: (a) the transmembrane electrostatically localized protons are not free to move away from the membrane surface as a protonic capacitor feature; (b) the proton pumps embedded in the cell membrane extend beyond the localized proton layer apparently as an asymmetric property of the biological membrane; and (c) the protonic inlet mouth of the ATP synthase that accepts protons is located within this layer as another natural property of the asymmetric biological membrane. This work has now, for the first time, shown a novel thermotrophic feature where biological systems can isothermally utilize environmental heat energy through transmembrane electrostatically localized protons to help drive ATP synthesis.

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For decades, it was not entirely clear why mitochondria develop cristae? The work employing the transmembrane-electrostatic proton localization theory reported here has now provided a clear answer to this fundamental question. Surprisingly, the transmembrane-electrostatically localized proton concentration at a curved mitochondrial crista tip can be significantly higher than that at the relatively flat membrane plane regions where the proton-pumping respiratory supercomplexes are situated. The biological significance for mitochondrial cristae has now, for the first time, been elucidated at a protonic bioenergetics level: 1) The formation of cristae creates more mitochondrial inner membrane surface area and thus more protonic capacitance for transmembrane-electrostatically localized proton energy storage; and 2) The geometric effect of a mitochondrial crista enhances the transmembrane-electrostatically localized proton density to the crista tip where the ATP synthase can readily utilize the localized proton density to drive ATP synthesis.

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Introduction: BP1 is a thermophilic strain of cyanobacteria that has an optimum growth at 57°C, and according to previous analysis by Yamaoka et al, BP1 cannot survive at a temperature below 30°C. This suggests that the thermophilic property of this strain may be used as a natural biosafety feature to limit the spread of genetically engineered (GE) organisms in the environment if physical containment fails.

Objective: To further explore the growth and survivability range of BP1, we report a growth and survivability assay of wild-type and GE BP1 strains under different conditions.

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In Mitchell's chemiosmotic theory, membrane potential was given as the electric potential difference across the membrane. However, its physical origin for membrane potential was not well explained. Using the Lee proton electrostatic localization model with a newly formulated equation for protonic motive force (pmf) that takes electrostatically localized protons into account, membrane potential has now been better understood as the voltage difference contributed by the localized surface charge density at the liquid-membrane interface as in an electrostatically localized protons/cations-membrane-anions capacitor.

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Horizontal gene transfer (HGT) is a natural process for an organism to transfer genetic material to another organism that is a completely different species, for example, from a blue-green alga to a non-photosynthetic bacterium. The phenomenon of HGT is not only of an interest to the science of molecular genetics and biology, but also to the biosafety issue of genetic engineering. The novel protocol reported here for the first time teaches how to measure HGT from a genetically engineered (GE) blue-green alga (gene donor) to wild-type (recipient).

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Synthetic biology with genetically engineered (GE) cyanobacteria has the potential to produce valuable products such as biofuels. However, it is also essential to assess the potential risks of synthetic biology technology before it can be widely used. In order to address key concerns posed by the application of synthetic biology to microorganisms, studies were designed to monitor the horizontal transfer of engineered genes from GE cyanobacteria Thermosynechococcus elongatus BP1 to Escherichia coli through co-incubation.

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Biochar was produced from pinewood biomass by pyrolysis at a highest treatment temperature (HTT) of 400 °C. This biochar was then treated with varying concentrations of H2O2 solution (1, 3, 10, 20, 30% w/w) for a partial oxygenation study. The biochar samples, both treated and untreated, were then tested with a cation exchange capacity (CEC) assay, Fourier Transformed Infrared Resonance (FT-IR), elemental analysis, field water-retention capacity assay, pH assay, and analyzed for their capacity to remove methylene blue from solution.

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Background: The combination of polycaprolactone and hyaluronic acid creates an ideal environment for wound healing. Hyaluronic acid maintains a moist wound environment and accelerates the in-growth of granulation tissue. Polycaprolactone has excellent mechanical strength, limits inflammation and is biocompatible.

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Biochars were produced from pinewood, peanut shell, and bamboo biomass through hydrothermal conversion (HTC) at 300 °C and comparatively by slow pyrolysis over a temperature range of 300, 400, and 500 °C. These biochars were characterized by FT-IR, cation exchange capacity (CEC) assay, methylene blue adsorption, as well as proximate and elemental analysis. The experimental results demonstrated higher retained oxygen content in biochars produced at lower pyrolysis temperatures and through HTC, which also correlated to the higher CEC of respective biochars.

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Biochar has gained significant interest worldwide for its potential use as both a carbon sequestration technique and soil amendment. Recently, research has shown that pinewood-derived biochar water extracts inhibited the growth of aquatic photosynthetic microorganisms, both prokaryotic and eukaryotic algae, while chicken litter- and peanut shell-derived biochar water extracts showed no growth inhibition. With the use of electrodialysis, the pinewood-derived biochar water extract is separated into 3 fractions (anode-isolated, center chamber retained, and cathode-isolated substances) all with varying toxic effects.

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Through cation exchange capacity assay, nitrogen adsorption-desorption surface area measurements, scanning electron microscopic imaging, infrared spectra and elemental analyses, we characterized biochar materials produced from cornstover under two different pyrolysis conditions, fast pyrolysis at 450 °C and gasification at 700 °C. Our experimental results showed that the cation exchange capacity (CEC) of the fast-pyrolytic char is about twice as high as that of the gasification char as well as that of a standard soil sample. The CEC values correlate well with the increase in the ratios of the oxygen atoms to the carbon atoms (O:C ratios) in the biochar materials.

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Objective: Prospective evaluation of outpatient cystoscopy in a Urogynaecology Unit.

Design: Prospective observational series.

Setting: St.

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We report a case of urethral diverticulectomy re-enforced with a porcine xenograft to prevent the risk of recurrence or fistula in the presence of a large urethral communication. The use of porcine small intestinal submucosal xenograft (SIS, Surgisis, Cook, Ireland) material has a low graft rejection rate and erosion is rare as the material is degraded after 3 to 6 months. In this case, xenograft achieved tension-free closure of the urethral defect without any postoperative complications.

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The objective of this prospective study was to evaluate the accuracy of conventional 2D ultrasound (CUS) versus doppler planimetry (DP) in the assessment of postpartum urinary bladder volume compared to a true estimate using urethral catheterisation. Fifty-two women were assessed within 24 hours of delivery. Evaluation of bladder volume was performed using CUS (1-estimate) and DP (6-estimates).

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Molecular dynamics simulations were performed to investigate the translocation of single-strand DNA through nanoscale electrode gaps under the action of a constant driving force. The application behind this theoretical study is a proposal to use nanoelectrodes as a screening gap as part of a rapid genomic sequencing device. Preliminary results from a series of simulations using various gap widths and driving forces suggest that the narrowest electrode gap that a single-strand DNA can pass is ∼1.

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A method of imaging nanometer metallocatalysts formed by photosynthetic precipitation of the water-soluble transition-metal compounds [PtCl(6)](2-) and [RuCl(6)](2-) is reported. Hexachloroplatinate and hexachlororuthenate can accept up to four electrons from Photosystem I (PSI) reaction centers in photosynthetic thylakoid membranes, thereby converting [PtCl(6)](2-) and [RuCl(6)](2-) anions to either metallic platinum (Pt) and ruthenium (Ru) and/or partially oxidized nanometer catalysts at the reducing sides of PSI molecules. Use of this method can potentially create nanometer-sized Pt and/or bimetallic catalysts (such as Pt-Ru) on biomembranes and molecules at pH 7 and room temperature with preservation of the biological function of the molecules.

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Female urethral diverticula.

Best Pract Res Clin Obstet Gynaecol

December 2005

Urethral diverticula are frequently under-diagnosed. The pathogenesis of this condition is poorly understood, and these lesions represent a spectrum of disorders ranging from isolated suburethral cysts to herniation of the urethral lining into the vaginal mucosa. Women with this disorder frequently complain of a host of symptoms referable to the lower urinary and genital tracts.

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