Differential absorption lidar data acquisition and control system for remote detection of trace chemicals including methane and thiodiglycol.

We report the design and development of a data acquisition and control system for high-speed acquisition of weak, backscattered differential signals and synchronized sequential operation of all subsystems of a tunable, mid-infrared Differential Absorption Lidar (DIAL) system. The presence of a low-level concentration of chemical species results in weak differential return signals. The differential signal also varies dynamically with respect to background atmospheric conditions. The challenge is to measure this low level of differential signal with high resolution and also control the sequence of operation of subsystems such as lasers and scanners for real time testing and evaluation in open field conditions. The concentration spread of the chemical species varies rapidly with distance. In order to capture this spatial variation, the lidar signal should be sampled and digitized at a high sampling rate. A customized Peripheral Component Interconnect based data acquisition of a 12-bit resolution, 30 Mega samples per second sampling rate, and an industrial personal computer-based control system has been realized. Detection algorithms and the firing sequence of the laser have been developed indigenously and implemented in the LabVIEW platform. The developed graphical user interface has various modes of operation as per user requirement and is capable of executing automatic operations for the developed DIAL system in order to detect and identify the chemicals. The performance has been evaluated by detecting the chemical species thiodiglycol at 800 m using 3190 and 3300 nm (online and offline wavelengths) with a differential cross-section of 2.5 × 10-23 m2. Similarly, methane has been detected and quantified with concentration of 2.2 ppm up to 300 m using 3316 and 3326 nm (online and offline wavelengths, respectively).

Cemento-ossifying fibroma--a rare case.

The concept of 'fibro-osseous lesions' of bone has evolved over the last several decades and now includes two major entities: fibrous dysplasia and ossifying fibroma, as well as the other less common lesions such as florid osseous dysplasia, periapical dysplasia, focal sclerosing osteomyelitis, proliferative periostitis of garrie, and ostitis deformans. The cemento-ossifying fibroma is a central neoplasm of bone as well as periodontium which has caused considerable controversy because of confusion regarding terminology and the criteria for its diagnosis. The cemento-ossifying fibroma is odontogenic in origin, whereas ossifying fibroma is of bony origin. This article reports a rare case of an 11-year-old male who came to us with the history of swelling in the maxillary anterior region causing difficulty in closing of mouth as well as in mastication.

Delayed replantation of avulsed teeth.

Dental injuries are very common and their extent has been classified by Ellis. Avulsion of tooth is a grievous injury and ranges from 1-16% among the traumatic injuries, of which maxillary anterior are commonest. Reimplantation of avulsed teeth is a standard procedure. However, it has certain limitations. Most often their management is very challenging. In this case report we are presenting the management of maxillary incisors by replantation after 36 hrs in a 12 year old girl.

Laparoscopic lateral pancreaticojejunostomy: our experience of 17 cases.

BACKGROUND: Although lateral pancreaticojejunostomy (LPJ) is one of the most commonly performed procedures for the management of chronic obstructive pancreatitis, it is seldom performed laparoscopically. We report our experience of 17 consecutive laparoscopic LPJ (lap LPJ) and their outcome. METHODS: Seventeen patients (nine male and eight female) with ages ranging between 16 and 48 years underwent lap LPJ by a single surgical team. The most common presenting symptoms were abdominal pain and weight loss. RESULTS: The mean operating times for lap LPJ and lap LPJ with one or more additional procedures were 277 min and 377 min, respectively. The mean hospital stay was 5.2 days. Conversion to laparotomy was required in four patients. There were no deaths and the overall complication rate was 11.8%. On follow-up, ranging from 3 months to 1 year, 82.3% of the patients were pain-free. CONCLUSIONS: Lateral pancreaticojejunostomy is the surgical procedure of choice for the management of chronic obstructive pancreatitis. The same procedure can be performed laparoscopically; although it is technically demanding, the results are excellent. However, the procedure is still in the early phase of feasibility owing to the limited number of cases reported in the world literature.

Mie lidar observations of lower tropospheric aerosols and clouds.

Mie lidar system is developed at Laser Science and Technology Centre, Delhi (28.38°N, 77.12°E) by using minimal number of commercially available off-the-shelf components. Neodymium Yttrium Aluminum Garnet (Nd:YAG) laser operating at 1064nm with variable pulse energies between 25 and 400 mJ with 10 Hz repetition rate and 7ns pulse duration is used as a transmitter and off-axis CASSEGRAIN telescope with 100mm diameter as a receiver. Silicon avalanche photodiode (Si-APD) module with built-in preamplifier and front-end optics is used as detector. This system has been developed for the studies of lower tropospheric aerosols and clouds. Some experiments have been conducted using this set up and preliminary results are discussed. The characteristics of backscattered signals for various transmitter pulse energies are also studied. Atmospheric aerosol extinction coefficient values are calculated using Klett lidar inversion algorithm. The extinction coefficient, in general, falls with range in the lower troposphere and the values lie typically in the range 7.5×10(-5) m(-1) to 1.12×10(-4) m(-1) in the absence of any cloud whereas this value shoots maximum up to 1.267×10(-3) m(-1) (peak extinction) in the presence of clouds.

Single Step Endodontic Management of Immature Apices using MTA.

AIM: To examine the clinical and radiographic appearance of teeth with immature apices that were treated by single step procedure using mineral trioxide aggregate (MTA). SUMMARY: Creation of a physiological hard tissue barrier with calcium hydroxide in a nonvital tooth although quite predictable has certain limitations, such as the very long duration of the treatment spread over multiple visits and increased risk of root fracture. Plugging the root canal end with MTA has been advocated as an alternative treatment modality for open apices. The technique has been proven to be successful in many recently reported cases. The cases reported here present the successful treatment of two traumatized maxillary central incisors with open apices and periapical lesions using MTA. In this case report, MTA has been used to create a hard tissue barrier after disinfection of the root canal.

A case report of cemento-ossifying fibroma.

The concept of 'fibro-osseous lesions' of bone evolved over the last several decades to include two major entities: fibrous dysplasia and ossifying fibroma as well as the other less common lesions such as florid osseous dysplasia, periapical dysplasia, focal sclerosing osteomyelitis, proliferative periostitis of garrie and ostitis deformans. The cemento-ossifying fibroma is a central neoplasm of bone as well as periodontium which has caused considerable controversy because of confusion of terminology and criteria of diagnosis. The cemento-ossifying fibroma is odontogenic in origin where as ossifying fibroma of bony origin. This article reports a case of an 11-year-old male who came to us with the history of swelling at the maxillary anterior region causing difficulty in closing of mouth as well as mastication.

Familial Cleidocranial Dysplasia.

Cleidocranial dysplasia or mutational dysostosis or cleidocranial dysostosis is a generalized skeletodental dysplastic disorder, inherited in an autosomal dominant pattern. The expression of this disorder can vary widely in severity, even within the same family. This is a relatively rare disease and has no standard effective treatment option as of yet. Here we present a case report of affected mother and son with classical manifestations of the disease.

Radix Entomolaris: A Clinical Challenge.

A major anatomical variant of the two-rooted mandibular first molar is a tooth with an additional distolingual third root: The radix entomolaris (RE). It is essential to anticipate and find all roots and canals during root canal treatment. Proper angulations and interpretation of radiographs help to identify pulp chamber and root anatomy. If present, an awareness and understanding of this unusual root and its root canal morphology can contribute to the successful outcome of root canal treatment.

Submerged and Impacted Primary Molars.

Submerged tooth is the one that is depressed below the occlusal plane. Dental ankylosis is thought to be a major cause of submergence. Submerged deciduous teeth have the potential to cause malocclusion not only by prevention of their exfoliation and subsequent replacement by permanent teeth but also by causing tilting of proximal teeth and extrusion of opposing tooth. The purpose of this report is to present three different cases of submerged deciduous teeth and their clinical effects.