Ultrafast Mid-Infrared Nanoscopy of Strained Vanadium Dioxide Nanobeams.

Long regarded as a model system for studying insulator-to-metal phase transitions, the correlated electron material vanadium dioxide (VO2) is now finding novel uses in device applications. Two of its most appealing aspects are its accessible transition temperature (∼341 K) and its rich phase diagram. Strain can be used to selectively stabilize different VO2 insulating phases by tuning the competition between electron and lattice degrees of freedom. It can even break the mesoscopic spatial symmetry of the transition, leading to a quasiperiodic ordering of insulating and metallic nanodomains. Nanostructuring of strained VO2 could potentially yield unique components for future devices. However, the most spectacular property of VO2--its ultrafast transition--has not yet been studied on the length scale of its phase heterogeneity. Here, we use ultrafast near-field microscopy in the mid-infrared to study individual, strained VO2 nanobeams on the 10 nm scale. We reveal a previously unseen correlation between the local steady-state switching susceptibility and the local ultrafast response to below-threshold photoexcitation. These results suggest that it may be possible to tailor the local photoresponse of VO2 using strain and thereby realize new types of ultrafast nano-optical devices.

Sensitivity and specificity of antiproliferative factor, heparin-binding epidermal growth factor-like growth factor, and epidermal growth factor as urine markers for interstitial cystitis.

We previously determined that the urine of interstitial cystitis (IC) patients specifically contains a factor (antiproliferative factor [APF]) that inhibits primary bladder epithelial cell proliferation, and that it has significantly decreased levels of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and increased levels of epidermal growth factor (EGF) compared with urine from asymptomatic controls and patients with bacterial cystitis. We sought to confirm the specificity of these findings for IC using a larger patient population, including control patients with a variety of urogenital disorders. Clean catch urine specimens were collected from 219 symptomatic IC patients, 113 asymptomatic controls without bladder disease, and 211 patients with various urogenital diseases including acute bacterial cystitis, vulvovaginitis, chronic nonbacterial prostatitis, overactive bladder, hematuria, stress incontinence, neurogenic bladder, benign prostatic hyperplasia, bladder or pelvic pain without voiding symptoms, bladder cancer, prostate cancer, or miscellaneous diagnoses including anatomic disorders. APF activity was determined by (3)H-thymidine incorporation into primary normal adult human bladder epithelial cells. HB-EGF and EGF levels were determined by enzyme-linked immunosorbent assay. APF activity was present significantly more often in IC than control urine specimens (P <0.005 for IC vs any control group; sensitivity = 94%, specificity = 95%, P <10(-82) for IC vs all controls). HB-EGF levels were also significantly lower and EGF levels significantly higher in IC urine than in specimens from controls (P <10(-84) and P <10(-36), respectively). These findings confirm the utility of APF, HB-EGF, and EGF as markers for IC. Understanding the reasons for altered levels of these markers may lead to understanding the pathogenesis of this disorder.

Pilot study of sequential oral antibiotics for the treatment of interstitial cystitis.

PURPOSE: Interstitial cystitis is a chronic disease of unknown etiology characterized by bladder pain, urgency and frequency. Although a single microbe has not been implicated as a cause of interstitial cystitis, several groups noted various organisms in the urine of some women with interstitial cystitis and some patients reported that antibiotics decrease symptoms. Consequently we performed a prospective, randomized, double-blinded, placebo controlled pilot study of sequential oral antibiotics. MATERIALS AND METHODS: We randomized 50 patients with interstitial cystitis to receive 18 weeks of placebo or antibiotics, including rifampin plus a sequence of doxycycline, erythromycin, metronidazole, clindamycin, amoxicillin and ciprofloxacin for 3 weeks each. RESULTS: Intent to treat analysis demonstrated that 12 of 25 patients (48%) in the antibiotic and 6 of 25 (24%) in the placebo group reported overall improvement (p = 0.14), while 10 and 5, respectively, noticed improvement in pain and urgency (p = 0.22). In the antibiotic group 20 participants (80%) had adverse effects compared with 10 (40%) in the placebo group (p = 0.009). CONCLUSIONS: Our findings suggest that these antibiotics alone or in combination may sometimes be associated with decreased symptoms in some patients but they do not represent a major advance in therapy for interstitial cystitis.