Electrical Double Layer of Supported Atomically Thin Materials.

The electrical double layer (EDL), consisting of two parallel layers of opposite charges, is foundational to many interfacial phenomena and unique in atomically thin materials. An important but unanswered question is how the "transparency" of atomically thin materials to their substrates influences the formation of the EDL. Here, we report that the EDL of graphene is directly affected by the surface energy of the underlying substrates. Cyclic voltammetry and electrochemical impedance spectroscopy measurements demonstrate that graphene on hydrophobic substrates exhibits an anomalously low EDL capacitance, much lower than what was previously measured for highly oriented pyrolytic graphite, suggesting disturbance of the EDL ("disordered EDL") formation due to the substrate-induced hydrophobicity to graphene. Similarly, electrostatic gating using EDL of graphene field-effect transistors shows much lower transconductance levels or even no gating for graphene on hydrophobic substrates, further supporting our hypothesis. Molecular dynamics simulations show that the EDL structure of graphene on a hydrophobic substrate is disordered, caused by the disruption of water dipole assemblies. Our study advances understanding of EDL in atomically thin limit.

Practice based collaboration to improve the use of immediate intravesical therapy after resection of nonmuscle invasive bladder cancer.

PURPOSE: Perioperative instillation of intravesical chemotherapy after bladder tumor resection is supported by level I evidence showing a 30% decrease in tumor recurrence. However, studies of administrative data sets show poor use in practice. MATERIALS AND METHODS: We prospectively evaluated the use of perioperative intravesical chemotherapy in a multipractice quality improvement collaborative. Cases were categorized as ideal for intravesical chemotherapy (1 or 2 papillary tumors, cTa/cT1 and completely resected) and nonideal. The reasons for not administering intravesical chemotherapy in ideal cases were classified as appropriate or modifiable. Before and after comparative feedback and educational interventions we calculated judicious use of intravesical chemotherapy (nonuse in nonideal cases plus use in ideal cases plus appropriate nonuse in ideal cases) and quality improvement potential (use in nonideal cases plus nonuse in ideal cases attributable to modifiable factors). RESULTS: We accrued a total of 2,794 cases at the 5 sites in 22 months. The rate of use in ideal cases was 38% before and 34.8% after intervention (p=0.36), while use in nonideal cases decreased from 15% to 12% (p=0.08). Overall, intravesical chemotherapy was used judiciously in 83.0% to 85.7% of cases, while the remaining 14.3% to 17.0% represented quality improvement potential. CONCLUSIONS: Judicious use of perioperative intravesical chemotherapy is relatively high in routine practice. Most instances of nonuse represent appropriate clinical judgment. Utilization did not change after quality improvement interventions, suggesting that there may a ceiling effect that makes it difficult to improve care that is high quality at baseline. Moreover, decreasing unnecessary use of an intervention may be easier than encouraging appropriate use of potentially toxic therapy.

Understanding the use of immediate intravesical chemotherapy for patients with bladder cancer.

PURPOSE: Despite its established efficacy in reducing recurrence rates for patients with urothelial carcinoma, immediate intravesical chemotherapy is reportedly used infrequently. Accordingly, the Urological Surgery Quality Collaborative implemented a project aimed at understanding and improving the use of immediate intravesical chemotherapy. MATERIALS AND METHODS: Surgeons in 5 Urological Surgery Quality Collaborative practices prospectively collected clinical and baseline intravesical chemotherapy use data for patients undergoing bladder biopsy or transurethral bladder tumor resection from September 2010 through January 2012. In the second phase of data collection (June 2011 through January 2012) treating surgeons also documented reasons for not administering intravesical chemotherapy. We defined patients with 1 to 2 clinical stage Ta/T1, completely resected, papillary tumor(s) as ideal candidates for treatment with immediate intravesical chemotherapy. For ideal and nonideal patients we examined baseline use of intravesical chemotherapy across Urological Surgery Quality Collaborative practices as well as reasons for not administering therapy among ideal patients. RESULTS: Among 1,931 patients 37.2% met criteria as ideal cases for intravesical chemotherapy administration. We observed significant variation in the use of intravesical chemotherapy across Urological Surgery Quality Collaborative practices for ideal (range 27% to 50%) and nonideal cases (9% to 24%) (p <0.001). Reasons for not treating ideal candidates included lack of confirmation of malignancy (4, 2.8%), uncertainty regarding the benefits of intravesical chemotherapy (28, 19.6%) and logistic factors such as the unavailability of medication (34, 23.8%). CONCLUSIONS: Use of immediate intravesical chemotherapy by Urological Surgery Quality Collaborative practices is higher than reported elsewhere but still varies widely, even among ideal candidates. Efforts to optimize use will be aided by disseminating evidence supporting indications and benefits of intravesical chemotherapy, and by addressing local logistic factors that limit access to this evidence-based therapy.

Regional collaboration to improve radiographic staging practices among men with early stage prostate cancer.

PURPOSE: We describe findings from a Urological Surgery Quality Collaborative project focused on improving the use of radiographic staging in men with newly diagnosed prostate cancer. MATERIALS AND METHODS: From May 2009 through September 2010 Urological Surgery Quality Collaborative surgeons collected uniform data for men with newly diagnosed prostate cancer. During this period we implemented 3 phases of data collection. Unlike the baseline phase, the second and third rounds were preceded by collaborative quality improvement interventions, including comparative performance feedback, and review and dissemination of clinical guidelines. We evaluated the use of bone scans and computerized tomography across prostate cancer risk strata, Urological Surgery Quality Collaborative practice locations, and before and after quality improvement interventions. RESULTS: We collected data for 858 men with prostate cancer. Based on the D'Amico classification 44%, 39% and 17% of the men had low, intermediate and high risk cancer, respectively. Overall 25% and 22% of patients underwent staging with a bone scan or computerized tomography, respectively, ordered by a Urological Surgery Quality Collaborative urologist. Urological Surgery Quality Collaborative practices differed significantly in their baseline use of bone scans and computerized tomography for men with low and intermediate risk cancer (p<0.01). Compared with baseline practice patterns (31% bone scans, 28% computerized tomography), urologists in Urological Surgery Quality Collaborative practices ordered fewer bone and computerized tomography scans in post-intervention phases 2 (23%, 21%) and 3 (16%, 13%) of data collection (p<0.01), including a significant reduction in the use of these studies in patients with low and intermediate risk cancer (p<0.05). CONCLUSIONS: Following collaborative feedback on baseline use and review of clinical guidelines, urologists in Urological Surgery Quality Collaborative practices dramatically reduced variations in practice patterns and improved adherence with recommended staging practices.

Establishment of a urological surgery quality collaborative.

PURPOSE: We describe the establishment of the Urological Surgery Quality Collaborative including our pilot project to improve radiographic staging for men with prostate cancer. MATERIALS AND METHODS: The Urological Surgery Quality Collaborative comprises more than 60 urologists from 3 group practices. From May through September 2009 Urological Surgery Quality Collaborative surgeons collected a uniform set of data (eg prostate specific antigen, clinical stage) for men with newly diagnosed prostate cancer. After categorizing the cancer of each patient as low, intermediate or high risk, we analyzed baseline use of staging studies across prostate cancer risk strata and Urological Surgery Quality Collaborative practice locations. RESULTS: Of 215 men with prostate cancer 34%, 42% and 24% had low, intermediate and high risk cancer, respectively. Overall 44% and 43% of patients underwent staging with a bone scan or computerized tomography, respectively, and only 9% and 7% of these studies, respectively, were positive for metastases. Use of staging studies increased across risk strata as bone scans or computerized tomography were performed in 17% and 18%, 41% and 40%, and 88% and 86% of patients, respectively, with low, intermediate and high risk tumors (p<0.01). For men with low risk prostate cancer the use of bone scans and computerized tomography differed significantly across Urological Surgery Quality Collaborative practices (p<0.01) and for this group only 1 bone scan (and no computerized tomography) was positive for metastases. CONCLUSIONS: Use of staging evaluations varies by prostate cancer risk strata and across Urological Surgery Quality Collaborative practices. By feeding these data back to surgeons we may be able to improve practice patterns and avoid unnecessary studies in low risk patients. Attainment of this goal would establish the Urological Surgery Quality Collaborative as a viable infrastructure for collaborative quality improvement in urology.

Crumpled Graphene Photodetector with Enhanced, Strain-Tunable, and Wavelength-Selective Photoresponsivity.

A stretchable photodetector with enhanced, strain-tunable photoresponsivity is developed based on crumpled graphene by engineering 2D graphene into 3D structures. This crumpled graphene photodetector demonstrates ≈400% enhanced photoresponsivity led by an order-of-magnitude enhanced extinction of graphene and 100% modulation in photoresponsivity with 200% applied strain. Finally, strain-tunable, wavelength-selective photodetection is shown by integrated colloidal photonic crystals-crumpled graphene photodetector devices.

The efficacy and safety of tadalafil in United States and Puerto Rican men with erectile dysfunction.

PURPOSE: We evaluate the efficacy and safety of tadalafil, taken as needed, in men with mild to severe erectile dysfunction (ED) and assess sexual intercourse attempt patterns. MATERIALS AND METHODS: In this multicenter, double-blind, placebo controlled, parallel study conducted in the United States and Puerto Rico 207 men with ED were randomized to placebo or 20 mg tadalafil for 12 weeks. The primary efficacy variables were changes from baseline in the mean International Index of Erectile Function erectile function domain score and mean per patient percentage of "yes" responses to Sexual Encounter Profile (SEP) diary questions 2 (successful penetration) and 3 (successful intercourse). The Global Assessment Question was a secondary end point and post hoc analyses on sexual intercourse attempt patterns were conducted. RESULTS: Men treated with tadalafil compared with placebo reported greater mean changes from baseline on the erectile function domain score (9.3 vs 0.3 with placebo, p <0.001) and on the mean per patient percentage of successful penetration (SEP question 2, 31.6% vs 2.3% with placebo, p <0.001) and successful intercourse attempts (SEP question 3, 43.6% vs 3.5% with placebo, p <0.001). The per treatment group percentage of successful intercourse attempts during treatment was higher for tadalafil than placebo (67.6% vs 24.1%, respectively, p <0.001) and most successful intercourse attempts occurred between 4 and 36 hours after taking tadalafil. Of the men treated with tadalafil 82.8% reported improved erections versus 19.6% taking placebo (Global Assessment Question, p <0.001). The most common treatment emergent adverse events were headache (15.7% vs 6.3% with placebo), back pain (8.8% vs 0%), and dyspepsia (7.5% vs 0%). CONCLUSIONS: Tadalafil (20 mg) significantly improved erectile function and patients did not closely temporally link sexual intercourse attempts with taking tadalafil. Tadalafil was also well tolerated in both groups of men with mild to severe ED.