Electrostatic Potentials and Fields in the Vicinity of Engineered Nanostructures

We have developed a method of calculation of the electrostatic potentials and fields in the vicinity of geometrically complex engineered nanostructures comprised of varying materials in electrolytes of arbitrary pH and ionic strength. The method involves direct summation of charged Debye-Hueckel spheres comprising the nanostructural surfaces and, by including charge redistribution on the surface of conducting materials held at constant potential, is applicable to mixed boundary conditions. The method is validated by comparison to analytical solutions for an infinite plane (Gouy-Chapman), an infinite cylinder (Bessel functions) and an infinite plane which contains a hole and which is held at constant potential. Excellent agreement between the potentials obtained by our numerical method and the closed form solutions is found for these conditions. The method is applied to the calculation of the electric field enhancement in the vicinity of a nanomembrane whose pore wall is held at constant charge and whose membrane surfaces are held at constant potential. The electric field is found to be enhanced by the charge buildup in the rim of the hole of the nanomembrane, which redistribution results from the potential being held constant in the conducting region. Ion concentrations are also calculated; positive ion rejection is found to be enhanced by this charge buildup in the region of the rim when a constant positive potential is applied

Silica Extraction at Mammoth Lakes, California

The purpose of this project is to develop a cost-effective method to extract marketable silica (SiO{sub 2}) from fluids at the Mammoth Lakes, California geothermal power plant. Silica provides an additional revenue source for the geothermal power industry and therefore lowers the costs of geothermal power production. The use of this type of ''solution mining'' to extract resources eliminates the need for acquiring these resources through energy intensive and environmentally damaging mining technologies. We have demonstrated that both precipitated and colloidal silica can be produced from the geothermal fluids at Mammoth Lakes by first concentrating the silica to over 600 ppm using reverse osmosis (RO). The RO permeate can be used in evaporative cooling at the plant; the RO concentrate is used for silica and potentially other resource extraction (Li, Cs, Rb). Preliminary results suggest that silica recovery at Mammoth Lakes could reduce the cost of geothermal electricity production by 1.0 cents/kWh

Silica Extraction at the Mammoth Lakes Geothermal Site

The purpose of this project is to develop a cost-effective method to extract marketable silica (SiO{sub 2}) from fluids at the Mammoth Lakes, California geothermal power plant. Marketable silica provides an additional revenue source for the geothermal power industry and therefore lowers the costs of geothermal power production. The use of this type of ''solution mining'' to extract resources from geothermal fluids eliminates the need for acquiring these resources through energy intensive and environmentally damaging mining technologies. We have demonstrated that both precipitated and colloidal silica can be produced from the geothermal fluids at Mammoth Lakes by first concentrating the silica to over 600 ppm using reverse osmosis (RO). The RO permeate can be used in evaporative cooling at the plant; the RO concentrate is used for silica and potentially other (Li, Cs, Rb) resource extraction. Preliminary results suggest that silica recovery at Mammoth Lakes could reduce the cost of geothermal electricity production by 1.0 cents/kWh

Primary liver cancer is more aggressive in HIV-HCV coinfection than in HCV infection. A prospective study (ANRS CO13 Hepavih and CO12 Cirvir)

OBJECTIVE: Since HAART, primary liver cancer has emerged as an increasing cause of morbidity and mortality in patients with HIV infection. Our aim was to compare characteristics and outcome of primary liver cancer according to HIV status in HCV cirrhotic patients submitted to periodic ultrasonographic surveillance. METHODS: All patients with primary liver cancer and cirrhosis were selected from two prospective cohorts (ANRS CO12 Cirvir, viral cirrhosis, n=1081; ANRS CO13 Hepavih, HIV-HCV coinfection, n=1175). Cirrhosis was diagnosed by liver biopsy in monoHCV group and biopsy and/or non-invasive tests in HIV-HCV group. Ultrasonographic surveillance was performed every 6 months. Diagnosis of primary liver cancer was established according to EASL-AASLD guidelines. RESULTS: Primary liver cancer was diagnosed in 32 patients, 16 in each group, and corresponded to hepatocellular carcinoma in all except for two cholangiocarcinomas in HIV-HCV patients. Ultrasonographic follow-up was similar (median time since last ultrasonographic without focal lesion: 237 days in HIV-HCV group (n=12) versus 208 days in HCV group, NS). At primary liver cancer diagnosis HIV-HCV patients were markedly younger (48 vs. 60 yrs, P<0.001), primary liver cancer was more advanced in HIV-HCV patients (single nodule: 43% vs. 75%, P=0.07; mean diameter of main nodule: 24 vs. 16 mm, P=0.006; portal obstruction: 3 vs. 0). Curative treatment was performed in four HIV-HCV patients versus 11 HCV patients (P=0.017). During follow-up, 10 HIV-HCV patients died versus only one HCV patient (P=0.0005). CONCLUSIONS: This result suggests more aggressiveness for tumors in HIV infected patients and, if confirmed, could result in shortening the length between ultrasonographic examinations

Position statement for the diagnosis and management of anogenital warts

Background: Anogenital warts (AGW) can cause economic burden on healthcare systems and are associated with emotional, psychological and physical issues. ----- Objective: To provide guidance to physicians on the diagnosis and management of AGW. ----- Methods: Fourteen global experts on AGW developed guidance on the diagnosis and management of AGW in an effort to unify international recommendations. Guidance was developed based on published international and national AGW guidelines and an evaluation of relevant literature published up to August 2016. Authors provided expert opinion based on their clinical experiences. ----- Results: A checklist for a patient's initial consultation is provided to help physicians when diagnosing AGW to get the relevant information from the patient in order to manage and treat the AGW effectively. A number of frequently asked questions are also provided to aid physicians when communicating with patients about AGW. Treatment of AGW should be individualized and selected based on the number, size, morphology, location, and keratinization of warts, and whether they are new or recurrent. Different techniques can be used to treat AGW including ablation, immunotherapy and other topical therapies. Combinations of these techniques are thought to be more effective at reducing AGW recurrence than monotherapy. A simplified algorithm was created suggesting patients with 1-5 warts should be treated with ablation followed by immunotherapy. Patients with >5 warts should use immunotherapy for 2 months followed by ablation and a second 2-month course of immunotherapy. Guidance for daily practice situations and the subsequent action that can be taken, as well as an algorithm for treatment of large warts, were also created. ----- Conclusion: The guidance provided will help physicians with the diagnosis and management of AGW in order to improve the health and quality of life of patients with AGW

The Effect of Tear Supplementation on Ocular Surface Sensations during the Interblink Interval in Patients with Dry Eye.

PURPOSE: To investigate the characteristics of ocular surface sensations and corneal sensitivity during the interblink interval before and after tear supplementation in dry eye patients. METHODS: Twenty subjects (41.88+/-14.37 years) with dry eye symptoms were included in the dry eye group. Fourteen subjects (39.13+/-11.27 years) without any clinical signs and/or symptoms of dry eye were included in the control group. Tear film dynamics was assessed by non-invasive tear film breakup time (NI-BUT) in parallel with continuous recordings of ocular sensations during forced blinking. Corneal sensitivity to selective stimulation of corneal mechano-, cold and chemical receptors was assessed using a gas esthesiometer. All the measurements were made before and 5 min after saline and hydroxypropyl-guar (HP-guar) drops. RESULTS: In dry eye patients the intensity of irritation increased rapidly after the last blink during forced blinking, while in controls there was no alteration in the intensity during the first 10 sec followed by an exponential increase. Irritation scores were significantly higher in dry eye patients throughout the entire interblink interval compared to controls (p0.05). CONCLUSION: Ocular surface irritation responses due to tear film drying are considerably increased in dry eye patients compared to normal subjects. Although tear supplementation improves the protective tear film layer, and thus reduce unpleasant sensory responses, the rapid rise in discomfort is still maintained and might be responsible for the remaining complaints of dry eye patients despite the treatment

Effectiveness of ophthalmic solution preservatives: a comparison of latanoprost with 0.02% benzalkonium chloride and travoprost with the sofZia preservative system

<p>Abstract</p> <p>Background</p> <p>Although in vitro and in vivo laboratory studies have suggested that benzalkonium chloride (BAK) in topical ophthalmic solutions may be detrimental to corneal epithelial cells, multiple short- and long-term clinical studies have provided evidence supporting the safety of BAK. Despite the conflicting evidence, BAK is the most commonly used preservative in ophthalmic products largely due to its proven antimicrobial efficacy. This study was designed to characterize the antimicrobial performance of two commonly used topical ocular hypotensive agents that employ different preservative systems: latanoprost 0.005% with 0.02% BAK and travoprost 0.004% with sofZia, a proprietary ionic buffer system.</p> <p>Methods</p> <p>Each product was tested for antimicrobial effectiveness by <it>European Pharmacopoeia </it>A (EP-A) standards, the most stringent standards of the three major compendia, which specify two early sampling time points (6 and 24 hours) not required by the <it>United States Pharmacopeia </it>or <it>Japanese Pharmacopoeia</it>. Aliquots were inoculated with between 10⁵and 10⁶colony-forming units of the test organisms: <it>Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans </it>and <it>Aspergillus brasiliensis</it>. Sampling and enumeration were conducted at protocol-defined time points through 28 days.</p> <p>Results</p> <p>BAK-containing latanoprost met EP-A criteria by immediately reducing all bacterial challenge organisms to the test sensitivity and fungal challenges within the first six hours while the preservative activity of travoprost with sofZia did not. Complete bacterial reduction by travoprost with sofZia was not shown until seven days into the test, and fungal reduction never exceeded the requisite 2 logs during the 28-day test. Travoprost with sofZia also did not meet EP-B criteria due to its limited effectiveness against <it>Staphylococcus aureus</it>. Both products satisfied United States and Japanese pharmacopoeial criteria.</p> <p>Conclusions</p> <p>Latanoprost with 0.02% BAK exhibited more effective microbial protection than travoprost with sofZia using rates of microbial reduction, time to no recovery for all challenges and evaluation against EP-A criteria as measures. The rapid and complete reduction of all microbial challenges demonstrates that antimicrobial activity of latanoprost with 0.02% BAK exceeds that of travoprost with sofZia preservative system in these products and provides a more protective environment in the event of contamination and subsequent exposure to microorganisms during use.</p