Experimental demonstration of square Fresnel zone plate with chiral side lobes.

In this study, we introduce what we believe is a novel holographic optical element called a chiral square Fresnel zone plate (CSFZP). The chirality is imposed on a square Fresnel zone plate (SFZP) using a nonclassical technique by rotating the half-period zones relative to one another. The rotation of the half-period zones, in turn, twists the side lobes of the diffraction pattern without altering the focusing properties inherent to a SFZP. As a consequence, the beam profile is hybrid, consisting of a strong central Gaussian focal spot with gradient force similar to that generated by a lens and twisted side lobes with orbital angular momentum. The optical fields at the focal plane were calculated and found to possess a whirlpool-phase profile and a twisted intensity profile. Analysis of the field variation along the direction of propagation revealed a spiraling phase and amplitude distribution. Poynting vector plot of the fields revealed the presence of angular momentum in the regions of chiral side lobes. The phase of the CSFZPs were displayed on a phase-only reflective spatial light modulator and illuminated using a laser. The intensity patterns recorded in the experiment match the calculated ones, with a strong central focal spot and twisted side lobes. The beam pattern was implemented in an optical trapping experiment and was found to possess particle trapping capabilities.

Correlation of narrow band imaging endoscopy and histopathology in the diagnosis of nonerosive reflux disease.

UNLABELLED: Background /Aim: Narrow band imaging (NBI) is a novel, innovative high-resolution endoscopic technique, which utilizes spectral narrow band filter for the visualization of mucosal patterns and microvasculature. Nonerosive reflux disease (NERD) is a type of gastroesophageal reflux disease (GERD) and it is characterized by reflux symptoms without mucosal breaks on white light endoscopy (WLE). Biopsies from distal esophagus of GERD patients show group of histologic features such as basal cell hyperplasia, elongation of lamina propria papillae, and inflammatory cells. The present study was undertaken to evaluate diagnostic utility of NBI endoscopy and biopsy study in NERD patients and also to correlate NBI endoscopy findings with histologic features of GERD. PATIENTS AND METHODS: A total of 71 cases of NERD having symptom score more than 10 and those not having erosion on WLE were recruited prospectively and underwent NBI endoscopic examination. Two mucosal biopsies were taken at 3 cm above the squamocolumnar junction. RESULTS: Histologic features of GERD were seen in 50 (70.4%) out of 71 cases. No significant correlation between NBI endoscopic findings with histologic features of GERD was found. CONCLUSION: The present study showed that histopathologic evaluation of distal esophageal mucosa has promising diagnostic value over NBI endoscopy in NERD patients. Use of newly introduced NBI technique requires tremendous familiarity for the detection of the cases of NERD, which show histologic features of GERD.

Endoscope versus microscope in the diagnosis of esophageal non-erosive reflux disease: a study of 71 cases.

BACKGROUND: Non-erosive reflux disease (NERD) is a type of gastroesophageal reflux disease (GERD) defined as symptomatic GERD without mucosal breaks on endoscopy. There is no gold standard for diagnosis of NERD till date. Biopsy from the distal esophagus in patients of GERD is said to reveal characteristic, although non-specific injury patterns such as squamous cell hyperplasia and intraepithelial inflammatory cell infiltration, collectively known as microscopic esophagitis. Recently, dilated intercellular spaces (DIS) are also shown to be associated with NERD. The present study was undertaken to evaluate the role of biopsy in NERD cases. MATERIALS AND METHODS: Two mucosal biopsies were taken at 3 cm above the squamocolumnar junction (SCJ) from 71 cases of NERD having symptom scores of more than 10. Biopsies were evaluated for features of microscopic esophagitis and DIS, and the results were analyzed. RESULTS: Fifty out of 71 (70.4%) patients with symptomatic NERD had features of microscopic esophagitis. DIS was noted in 46/71 (64.8%) of cases, and correlated significantly with microscopic esophagitis (p<0.0001). Basal cell hyperplasia, papillary elongation, intraepithelial neutrophils, and intraepithelial eosinophils were seen in 83.1%, 76.1%, 40.8%, and 12.7% of NERD cases respectively. CONCLUSION: In symptomatic patients of GERD, when endoscopy does not show mucosal breaks (so called NERD), histopathological evaluation of distal esophageal mucosa may have a diagnostic value. The present study also reinforces the diagnostic utility of DIS in symptomatic NERD.