Catalytic Intervention of MoO3 toward Ethanol Oxidation on PtPd Nanoparticles Decorated MoO3-Polypyrrole Composite Support.

Ethanol oxidation reaction has been studied in acidic environment over PtPd nanoparticles (NPs) grown on the molybdenum oxide-polypyrrole composite (MOPC) support. The attempt was focused on using reduced Pt loading on non-carbon support for direct ethanol fuel cell (DEFC) operated with proton exchange membrane (PEM). As revealed in SEM study, a molybdenum oxide network exists in polypyrrole caging and the presence of metal NPs over the composite matrix is confirmed by TEM analysis. Further physicochemical characterizations such as XRD, EDAX, and XPS are followed in order to understand the surface morphology and composition of the hybrid structure. Electrochemical techniques such as voltammetry, choroamperometry, and impedance spectroscopy along with performance testing of an in-house-fabricated fuel cell are carried out to evaluate the catalytic activity of the materials for DEFC. The reaction products are estimated by ion chromatographic analysis. Considering the results obtained from the above characterization procedures, the best catalytic performance is exhibited by the Pt-Pd (1:1) on MOPC support. A clear intervention of the molybdenum oxide network is strongly advocated in the EOR sequence which increases the propensity of the reaction by making the metallites more energy efficient in terms of harnessing sufficient numbers of electrons than with the carbon support.

Design, development, and clinical evaluation of the electronic mobility cane for vision rehabilitation.

This paper proposes a new electronic mobility cane (EMC) for providing obstacle detection and way-finding assistance to the visually impaired people. The main feature of this cane is that it constructs the logical map of the surrounding environment to deduce the priority information. It provides a simplified representation of the surrounding environment without causing any information overload. It conveys this priority information to the subject by using intuitive vibration, audio or voice feedback. The other novel features of the EMC are staircase detection and nonformal distance scaling scheme. It also provides information about the floor status. It consists of a low power embedded system with ultrasonic sensors and safety indicators. The EMC was subjected to series of clinical evaluations in order to verify its design and to assess its ability to assist the subjects in their daily-life mobility. Clinical evaluations were performed with 16 totally blind and four low vision subjects. All subjects walked controlled and the real-world test environments with the EMC and the traditional white cane. The evaluation results and significant scores of subjective measurements have shown the usefulness of the EMC in vision rehabilitation services.

Electronic bracelet and vision-enabled waist-belt for mobility of visually impaired people.

A wearable assistive system is proposed to improve mobility of visually impaired people (subjects). This system has been implemented in the shape of a bracelet and waist-belt in order to increase its wearable convenience and cosmetic acceptability. A camera and an ultrasonic sensor are attached to a customized waist-belt and bracelet, respectively. The proposed modular system will act as a complementary aid along with a white cane. Its vision-enabled waist-belt module detects the path and distribution of obstacles on the path. This module conveys the required information to a subject via a mono earphone by activating relevant spoken messages. The electronic bracelet module assists the subject to verify this information and to perceive distance of obstacles along with their locations. The proposed complementary system provides an improved understanding of the surrounding environment with less cognitive and perceptual efforts as compared to a white cane alone. This system was subjected to clinical evaluations with 15 totally blind subjects. Results of usability experiments demonstrated effectiveness of the system as a mobility aid. Amongst the participated subjects, 93.33% expressed satisfaction with the information content of this system, 86.66% subjects comprehended its operational convenience, and 80% appreciated the comfort of the system.

Dielectric and conductivity characteristics of CuCl2 doped poly(N-vinyl carbazole) and its hybrid nanocomposite with Fe3O4.

Copper(II) chloride (CuCl2) doped poly(N-vinyl carbazole) (PNVC)-ferric oxide (Fe3O4) hybrid composites have been prepared and characterized by Fourier transform infrared spectroscopic studies, UV-Vis spectroscopy, high resolution transmission electron microscopy (HRTEM) and X-ray diffraction analyses and evaluated in regard to dielectric response and ac/dc conductivity characteristics. HRTEM images for CuCl2-(PNVC-Fe3O4) composite indicate the co-existence of both the CuCl2 and Fe3O4 nanoparticles in the composite and characteristic lattice fringes are clearly observed which endorse the formation of thin layer interfaces between Fe3O4 and CuCl2 nanoparticles. The dielectric constants of the CuCl2 doped PNVC and PNVC-Fe3O4 composites increase substantially relative to the corresponding values of the polymer and the polymer composite respectively. Likewise, the conductivities (ac and dc) are also improved substantially after doping with CuCl2. The dependence of these functional properties on the extent of metal salt loading has been evaluated and a quantitative estimation of the contribution of the grain boundary and resistance parameters has been attempted in terms of Maxwell-Wagner two-layered model.

Dielectric properties of polyaniline-montmorillonite clay hybrids.

Polyaniline (PANI)-montmorillonite clay (MMT) hybrid (PANI-MMT) was prepared by mechanical grinding of ANI and MMT in the presence of potassium perdisulphate (KPS) followed by soaking the mass in 0.1 (M) HCI for 24 h. The formation of PANI-MMT hybrid was confirmed by Fourier transform infrared spectroscopic analyses. XRD studies revealed the intercalation of PANI into two-dimensional silicate galleries of MMT HRTEM analyses indicated particle size distribution to be in the range of 40-55 nm. The real part of the dielectric constant reached values as high as 4500 at frequency - 10(2) Hz for a MMT:PANI = 1:1 weight ratio, the value decreasing with increasing frequency up to 25 kHz, and also with increasing MMT loading in the hybrids. This dispersion was indicative of the interfacial space charge polarization (Maxwell Wagner type). Grain boundary resistance and capacitance of the hybrid along with the conductivity-relaxation time for the hybrid at several PANI:MMT weight ratios were evaluated from the complex impedance plot considering the Maxwell-Wagner Two-Layered Model AC conductivity was independent of frequency in the range 0.1-1 kHz and thereafter found to rise in the range 1-25 kHz due to trapped charges. DC conductivity values of the hybrids were lower than the PANI homopolymer.

Rare persistent kerato-acanthoma of left lower eyelid: a case report.

A 45-year-old man presented with a mass in left lower eyelid. On examination, the mass was diagnosed as kerato-acanthoma. The mass was excised and excision biopsy confirmed the diagnosis. Kerato-acanthoma almost always regress spontaneously within six months. So persistence of the lesion for more than one year is a rare presentation.

Morphological, dielectric and electrical conductivity characteristics of clay-containing nanohybrids of poly(N-vinyl carbazole) and polypyrrole.

Poly(N-vinyl carbazole) (PNVC) and polypyrrole (PPY)-montmorillonite (MMT) clay hybrids were prepared by mechanical grinding of the respective monomers with MMT followed by subsequent standard processing methods. Fourier transform infrared spectroscopic studies confirmed the inclusion of the polymers in the composites. The morphologies of the hybrids were investigated by transmission electron microscopic techniques, which suggested the formation of intercalated structures. X-ray diffraction analyses indicated the enhancement of 'd001' values in MMT implying intercalation of the polymers into the nano-interlamellar spaces of MMT. The dielectric constants of PNVC-MMT hybrids were improved (60-180) relative to the homopolymer (3-6) in the frequency range 0.1-25 kHz. PPY-MMT hybrid also showed significantly higher values of dielectric constant (2000-4000) relative to the corresponding base polymers. These variations were dependent on the MMT/polymer feed ratio in the frequency range (1-25 kHz). This feature could manifest from the characteristic differences in the interfaces between the grains and grain boundaries of the composites, which control the dielectric properties of the system. Relaxation behavior for the composites was explained by considering the Maxwell-Wagner two-layered dielectric models. The ac conductivity was found to be dependent on frequency in the entire frequency range of study (100 Hz to 25 kHz), which indicated that the composites had few free charges for conduction, and frequency dependent conductivity was due to trapped charges in the grain boundary.

Ocular manifestations in children with cerebral palsy.

To evaluate the prevalence of ocular abnormalities among children with cerebral palsy, 140 patients with age between 6 months and 16 years were selected and the overall incidence of ocular abnormalities in this study was 42.1%. Two major ocular abnormalities identified in these cases were strabismus in 36.4%. Myopia was detected in 12.9% children while hypermetropia in 8.6% and astigmatism in 3.6% cases. Non-glaucomatous optic atrophy was present in 10.7% cases and nystagmus in 9.3% cases. Raised intra-ocular pressure was detected in 2.1% cases. Cortical visual impairment was seen in 20.7% children. Ocular abnormalities are frequent manifestations in cerebral palsy patients. Therefore, evaluation of all cerebral palsy cases emphasises the need for a full ophthalmological examination in order to detect ocular problems and to institute necessary therapy of the abnormalities for better livelihood of these physically challenged patients.

Ocular effects of long term use of topical steroids among children and adolescents with vernal keratoconjunctivitis: a prospective observational study.

Topical steroids were often irrationally used on long term basis for quick relief from ocular discomfort of inflammatory eye conditions like vernal keratoconjunctivitis in spite of their well known deleterious ocular effects. The present study was undertaken to determine the ocular effects of long term use of topical steroids among the patients with vernal keratoconjunctivitis and also to evaluate the ocular responses after withdrawal of steroids. The prospective observational study was carried out in a tertiary eye care centre of West Bengal. A total 150 referred patients of vernal keratoconjunctivitis, those used topical steroids for more than a month were included in the study. A complete set of ophthalmic examinations including measurement of intra-ocular pressure and visual acuity was carried out during registration. After withdrawal of steroids, the patients were followed-up periodically and finally evaluated after 8 weeks for any Improvement of Intra-ocular pressure and best corrected visual acuity. The data was analysed by SPSS 12.0.1 software package. Proportions were used for Interpretation. Paired t-test was used for comparison between two proportions (before and after withdrawal of steroids) and p-value <0.05 was considered as the level of significance. Though ropy mucus discharge with minimal conjunctival involvement was found the most common (74.7%) ocular manifestation, grave consequences like glaucoma was also evident among 8.7% of the study participants. Significant improvements (p<0.05) were observed for both reduction of intra-ocular pressure and visual acuity after 8 weeks of withdrawal of topical steroids. Topical steroids should be used cautiously with periodic ophthalmic examinations including intra-ocular pressure.

Changing trends of ocular anaesthesia in phaco-emulsification surgery.

This study was undertaken prospectively to assess the safety and effectiveness of topical anaeshthesia over sub-tenon and peribulbar anaesthesia during routine phaco-emulsification surgery. One hundred and fifty eyes undergoing clear corneal phaco-emulsification were randomly divided into 3 groups. Pain was assessed subjectively by the patients during introduction of anaesthetic agent, also intra-operatively and 2 hours postoperatively on a visual analogue scale of 0 to 4 by the visual descriptive method. Ocular akinesia at the beginning and during the surgery was recorded by the operating surgeon. Any intra-operative complication was also noted at the end of the surgery. This analysis showed that topical anaesthesia caused no pain at all in 98% and sub-tenon anaesthesia caused minimum or no pain in 92% during introduction of anaesthetic agent as opposed to peribulbar (42%) and two values were also statistically significant. Sub-tenon and peribulbar anaesthesia provided significantly more intra-operative akinesia as compared to topical, the rate of intra-operative complications was comparable in all the 3 groups. So the recent trend of topical anaesthesia in phacosurgery is a safe and efficient alternative to sub-tenon and peribulbar anaesthesia.

Tissue adhesive in ophthalmology.

Tissue adhesive in ophthalmology is commonly used for corneal wound and restricted for superficial closure. Only synthetic adhesive available is butyl-2-cyanoacrylate. However, if it gets between the wound margins it inhibits healing by forming impervious barrier.

Clinicobacteriological study of chronic dacryocystitis in adults.

Chronic dacryocystitis is the inflammation of lacrimal sac, frequently caused by bacteria. Obstruction of nasolacrimal duct converts the lacrimal sac a reservoir of infection. It is a constant threat to cornea and orbital soft tissue. Moreover, it causes social embarrassment due to chronic watering from the eye. This study was conducted to find out the current clinicobacteriological profile of chronic dacryocystitis in adults. A total of 56 adult patients were selected from ophthalmology OPD. Detail history and clinical examinations were carried out. All patients underwent either dacryocystorhinostomy or dacryocystectomy. A part of the sac was collected for culture and sensitivity. This study revealed that chronic dacryocystitis is more common in females and left eye is more frequently involved than right eye. It is common among lower socioeconomic strata with habit of pond-bathing. Some form of nasal pathology like hypertrophied inferior turbinate, deviated nasal septum, nasal polyp and allergic rhinitis werefound in 19.6% of the patients. Complications of chronic dacryocystitis like conjunctivitis, corneal ulcer, acute on chronic dacryocystitis, lacrimal abscess and fistula were seen in 25.0% of these patients; 53.6% of the culture samples were positive for bacterial growth. Gram-positive organisms were most common isolate. Unlike other studies, Staphylococcus aureus (40.0%) was found to be most common Gram-positive organism, followed by Staphylococcus epidermidis (10.0%) and Steptococcus pneumoniae (10.0%). Among the Gram-negative organisms, Pseudomonas aeruginosa (16.6%) was the most common, followed by Klebsiella pneumoniae (6.6%) and Haemophilus influenzae (6.6%). Antibiotic sensitivity tests were done. Most of the organisms were resistant to penicillin. Chloramphenicol was effective against most of the Gram-positive organisms. Aminoglycosides, tobramycin in particular, was effective against Staphylococcus epidermidis. Fluoroquinolones, namely ciprofloxacin and ofloxacin were effective against Pseudomonas aeruginosa and Klebsiella pneumoniae.

Preparation and properties of poly(N-vinylcarbazole) and MWCNT nanocomposites.

N-vinylcarbazole (NVC) was polymerized in bulk through the interaction of multi-walled carbon nanotube (MWCNT) without any extraneous catalyst. A PNVC-MWCNT composite was isolated by MeOH precipitation of a polymerization system containing NVC and MWCNT at melting temperature of the monomer. The inclusion of PNVC in the composite was endorsed by the FTIR study. TG analysis revealed the thermal stability trend as MWCNT > PNVC-MWCNT composite > PNVC. DTA showed two exothermic peaks at 427 degrees C and 607 degrees C in the PNVC-MWCNT composite. Transmission electron microscopic analyses of MWCNT revealed presence of tubular MWCNT particles with diameters in nm range while the corresponding analysis for the composite showed the formation of spherical dark polymer particles encapsulating cylindrical MWCNT moieties with some ends of uncoated MWCNT tubes (light shades) protruding out of the dark spherical particles. Scanning electron microscopic analysis revealed presence of tubular CNT particles entangled with the composite particles of irregular shapes and sizes. XRD analysis revealed no additional crystalline peaks for PNVC in the composite. In contrast to PNVC homopolymer (10(-12)-10(-16) S/cm), the dc conductivity values of the composite varied form 1.3 to 33 S/cm depending upon the weight ratio of MWCNT and PNVC in the composite. Current-voltage characteristics of the composite showed a linear variation and conductivity-temperature studies revealed an increase in conductivity by 35% in the temperature range 150-220 degrees C.

Treatment of pterygium with conjunctival limbal autograft and mitomycin C--a comparative study.

A total of 60 eyes with primary progressive pterygium were selected. They were randomly divided into two groups ie, group A and group B each consisting of 30 eyes. Group A patients were treated with pteryglum excision with ipsilateral conjunctival-limbal autografting. Group B patients were treated with pterygium excision followed by mitomycin C 0.02% for two minutes. Both groups were followed up for one year postoperatively to document recurrence rates and postoperative complications. In group A recurrence rate was 3.0% with minimal ocular complication after one year follow-up. But in group B recurrence rate was high as 10.0% and ocular complications were significant after the same period of postoperative follow-up. Both conjunctival-limbal autograft and intra-operative mitomycin use are effective method of surgical treatment of pterygium but considering the rate of recurrence and other postoperative ocular morbidity conjunctival-limbal autografting seems to be the best method of pterygium treatment.

Bacteriological profile in chronic dacryocystitis.

A study was conducted to see the bacteriological profile in 172 cases of chronic dacryocystitis attending eye outpatients department of Midnapore Medical College and Hospital and NRS Medical College and Hospital, Kolkata. The patients underwent clinical examination of the eyes and lacrimal system, with particular attention to drainage system. The culture and sensitivity test was done from the material, which regurgitated through the punctum following pressure on sac. Out of 172 cases, 66(38.4%) were found with epiphora, 44 cases (25.9%) of epiphora with mass, 8 cases (4.6%) with epiphora mass with cellulitis and in 54 (31.4%) with chronic conjunctivitis. Bactriologically, 142 patients (82.5%) were revealed with pure culture, mixed culture in 18 cases (10.5%) and no growth of organism in 12 cases (7.0%). Staphylococcus aureus was found primary pathogen in disease process. Candida albicans were seen in 4 cases (2.3%).

Xerophthalmia: a study among malnourished children of West Mednipur District.

To study the correlation of stages of xerophthalmia in different grades of malnutrition, having 200 children clinically diagnosed having malnutrition as per criteria laid down by the Indian Academy of Pediatrics (IAP) were examined to detect the dinical stages of xerophthalmia as proposed by World Health Organisation (WHO). Out of 200 cases with different grades of malnutrition 81 (40.5%), 78 (39.0%), 22 (11.0%) and 19 (9.5%) were found malnourished in grades I, II, III, and IV respectively. Night blindness was earliest feature and seen in 97 cases (48.5%). All the 97 cases of night blindness fell in group of X(N) in which one case had corneal scar and falls in the group of X(S) in clinical staging of xerophthalmia. Thirty-nine (40.2%), 35 (36.1%), 19 (19.6%), 3 (3.1%) and (1.1%) were in clinical stages of xerophthalmia of X(1A), X(1B), X2, X(3A), X(3B)respectively. Severity of xerophthalmia was found directly proportional to severity of malnutrition.

Malignant melanoma of conjunctiva--a case report.

A 65-year-old male patient presented with a rapidly increasing mass in his left eye. It did not show any intra-ocular extension as examined by slit lamp, gonioscopy, indirect ophthalmoscopy and ultrasonography, nor there was any sign of systemic metastasis. The mass was excised completely. Buccal mucous membrane grafting was done to cover up the lower forniceal area and conjunctival autograft taken from right eye and placed over upper fornix and bulbar area. Postoperative radiotherapy was suggested. Histopathological examination of the mass revealed the diagnosis of malignant melanoma of conjunctiva.

Rheumatoid arthritis and ocular involvement.

To study the occurrence and incidence of different ocular manifestations in rheumatoid arthritis a random cross-sectional study was carried out among 54 patients with active rheumatoid arthritis. The patients were examined thoroughly to detect any ocular disease associated with rheumatoid arthritis. Complete ocular examination with special emphasis on anterior segment evaluation and tearfilm study was done. Two-thirds of the patients examined had some kind of visual problem at presentation. Three patients (5.55%) had marked dry eye with another 20 (37.03%) having borderline tear deficiency. Two cases ( 3.70% ) of episcleritis were also seen. No cases of scleritis or retinopathy were found. The most common ocular association with rheumatoid arthritis was secondary Sjogren's syndrome. Other conditions include episcleritis and marginal keratitis.

Clinical pattern of ocular manifestations in vitiligo.

To study the ocular abnormalities in cases of vitiligo, 100 patients were examined who underwent a series of investigations e.g., complete haemogram, urine analysis, blood biochemistry and chest x-ray and 70 cases were taken as control. Patients with systemic diseases such as diabetes mellitus, thyroid and auto-immune disorders were excluded. Detailed ocular examinations including recording of vision, slit-lamp biomicroscopy, gonioscopy, ophthalmoscopy and examination of fundus by 90 D lens were done. Of 100 vitiligo patients, 23% showed hypopigmented sports on the iris, 18% pigmentation on anterior chamber, 9% retinal pigment epithelium hypopigmentation, 5% uveitis, 11% had chorioretinal degeneration and 34% had no ocular findings. There lies a strong association of ocular disorder in patients with vitiligo.