Microwave-assisted synthesis and upconversion luminescence of NaYF4:Yb, Gd, Er and NaYF4:Yb, Gd, Tm nanorods.

Anisotropic rare earth ion (RE3+) doped fluoride upconversion particles are emerging as potential candidate in diverse areas, ranging from biomedical imaging to photonics. Here, we develop a facile strategy to synthesize NaYF4: Yb, Gd, Er, and NaYF4: Yb, Gd, Tm upconversion nanorods via microwave synthesis route by controlling the synthesis time and compared the optical properties similar nanorods prepared via solvothermal technique. With the increase in synthesis time, the phase of the particle found to change from mixed phase to purely hexagonal and morphology of the particles change mixed phase of spherical and rod-shaped particles to completely nanorods for a synthesis time of 60 min. Further, the intrinsically hydrophobic particles changed to hydrophilic by removal of oleic capping via acid treatment and the amine functionalized silica coating. The upconversion luminescence as well as laser power dependent emission properties of the surface modified particles elucidate that surface modification route influence the upconversion luminescence as well as solvent dependent emission properties. Moreover, the laser power dependent studies elucidate that the upconversion process in a multi-photon process.

Speech Signal Analysis and Pattern Recognition in Diagnosis of Dysarthria.

BACKGROUND: Dysarthria refers to a group of disorders resulting from disturbances in muscular control over the speech mechanism due to damage of central or peripheral nervous system. There is wide subjective variability in assessment of dysarthria between different clinicians. In our study, we tried to identify a pattern among types of dysarthria by acoustic analysis and to prevent intersubject variability. OBJECTIVES: (1) Pattern recognition among types of dysarthria with software tool and to compare with normal subjects. (2) To assess the severity of dysarthria with software tool. MATERIALS AND METHODS: Speech of seventy subjects were recorded, both normal subjects and the dysarthric patients who attended the outpatient department/admitted in AIMS. Speech waveforms were analyzed using Praat and MATHLAB toolkit. The pitch contour, formant variation, and speech duration of the extracted graphs were analyzed. RESULTS: Study population included 25 normal subjects and 45 dysarthric patients. Dysarthric subjects included 24 patients with extrapyramidal dysarthria, 14 cases of spastic dysarthria, and 7 cases of ataxic dysarthria. Analysis of pitch of the study population showed a specific pattern in each type. F0 jitter was found in spastic dysarthria, pitch break with ataxic dysarthria, and pitch monotonicity with extrapyramidal dysarthria. By pattern recognition, we identified 19 cases in which one or more recognized patterns coexisted. There was a significant correlation between the severity of dysarthria and formant range. CONCLUSIONS: Specific patterns were identified for types of dysarthria so that this software tool will help clinicians to identify the types of dysarthria in a better way and could prevent intersubject variability. We also assessed the severity of dysarthria by formant range. Mixed dysarthria can be more common than clinically expected.

Towards enhancing the performance of multi-parameter patient monitors.

Multi-parameter patient monitors (MPMs) have become increasingly important in providing quality healthcare to patients. It is well known in the medical community that there exists an intrinsic relationship between different vital parameters in a healthy person, these include heart rate, blood pressure, respiration rate and oxygen saturation. For example, an increase in blood pressure would lead to a decrease in the heart rate, and vice versa. Although it is likely to improve the performance of MPM systems, this fact is not explored in engineering research. In this work, experiments show that deriving additional features to capture the intrinsic relationship between the vital parameters, the alarm accuracy (sensitivity), no-alarm accuracy (specificity) and the overall performance of MPMs can be improved. The geometric mean of the product of all the vital parameters taken in pairs of two was used to capture the intrinsic relationship between the different parameters. An improvement of 10.55% for sensitivity, 0.32% for specificity and an overall performance improvement of 1.03% was obtained, compared to the baseline system using classification and regression tree with the four vital parameters.

Molecular predictors in the early diagnosis of oral cancer.

Human beings are being subjected to a variety of disease processes, a majority of which can be cured. However, cancer remains an endangering disease that affects various body parts. Though cancers can be prevented by various therapeutic modalities, the patient survival and the prognosis are questionable, as they are detected at very late stages. The aim of improving the prognosis lies in an early detection of the cancer, which can be brought about by an analysis of the changes in the cellular biomolecules.

Studies on phytoplankton characteristics in Ayyampattinam coast, India.

Physico-chemical variables in the marine environment are subjected to wide spatio-temporal variations. The various physico-chemical parameters viz: temperature, salinity, pH, dissolved oxygen and nutrients of the environment are the factors which mainly influence the production and successful propagation of planktonic life in the coastal biotopes. The ranges of values of surface water temperature (0 degrees C), salinity (per thousand), pH and dissolved oxygen (ml l(-1)) were: 25.5 - 33.4; 23 - 35; 7.8 - 8.2; 3.6 - 5.2, respectively. The values (microg l(-1)) of nutrients were: nitrate 3.21 - 6.34, nitrite 0.74 - 0.896, phosphate 0.22 and 1.16, silicate 24.85 - 61.92 and ammonia 0.05 - 0.32. The recorded values of primary productivity (mgcm(-3)hr(1)) ranged between 16 - 116 and the chlorophyll "a" varied from 3.74 - 8.52. A total number of 51 species of phytoplankton representing different classes viz: Bacillariophyceae (40); Dinophyceae (8); Chlorophyceae (1) and Cyanophyceae (2) was recorded. Among the four classes, Bacillariophyceae appeared to be the dominant group in respect of total species and cell numbers. The population density of phytoplankton was high during summer season and quite low during monsoon season.

Lipid lowering activity of Eclipta prostrata in experimental hyperlipidemia.

The plant Eclipta prostrata is used in the traditional medical practices of India to treat hepatic diseases and hyperlipidemia. The total alcoholic extract of the plant when tested for antihyperlipidemic potential, exhibited a dose-dependent activity in albino rats when compared to standard drugs. The activity was assessed by studying the lipid profiles of serum, liver and heart of the control and drug-treated animals. The results lend support to the traditional use of Eclipta prostrata in the treatment of hyperlipidemia.