2,717 research outputs found

    Giant dipole resonance with exact treatment of thermal fluctuations

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    The shape fluctuations due to thermal effects in the giant dipole resonance (GDR) observables are calculated using the exact free energies evaluated at fixed spin and temperature. The results obtained are compared with Landau theory calculations done by parameterizing the free energy. The Landau theory is found to be insufficient when the shell effects are dominating.Comment: 5 pages, 2 figure

    High pressure pyrolyzed non-precious metal oxygen reduction catalysts for alkaline polymer electrolyte membrane fuel cells

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    Non-precious metal catalysts, such as metal-coordinated to nitrogen doped-carbon, have shown reasonable oxygen reduction reaction (ORR) performances in alkaline fuel cells. In this report, we present the development of a highly active, stable and low-cost non-precious metal ORR catalyst by direct synthesis under autogenic-pressure conditions. Transmission electron microscopy studies show highly porous Fe-N-C and Co-N-C structures, which were further confirmed by Brunauer-Emmett-Teller surface area measurements. The surface areas of the Fe-N-C and Co-N-C catalysts were found to be 377.5 and 369.3 m2 g-1, respectively. XPS results show the possible existence of N-C and M-Nx structures, which are generally proposed to be the active sites in non-precious metal catalysts. The Fe-N-C electrocatalyst exhibits an ORR half-wave potential 20 mV higher than the reference Pt/C catalyst. The cycling durability test for Fe-N-C over 5000 cycles shows that the half-wave potential lost only 4 mV, whereas the half-wave potential of the Pt/C catalyst lost about 50 mV. The Fe-N-C catalyst exhibited an improved activity and stability compared to the reference Pt/C catalyst and it possesses a direct 4-electron transfer pathway for the ORR process. Further, the Fe-N-C catalyst produces extremely low HO2- content, as confirmed by the rotating ring-disk electrode measurements. In the alkaline fuel single cell tests, maximum power densities of 75 and 80 mW cm-2 were observed for the Fe-N-C and Pt/C cathodes, respectively. Durability studies (100 h) showed that decay of the fuel cell current was more prominent for the Pt/C cathode catalyst compared to the Fe-N-C cathode catalyst. Therefore, the Fe-N-C catalyst appears to be a promising new class of non-precious metal catalysts prepared by an autogenic synthetic method. © The Royal Society of Chemistry 2015.

    Combined spectral and spatial processing of ERTS imagery data

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    A procedure for extracting a set of textural features for ERTS-1 MSS data is presented. The textural features were combined with a set of spectral features and were used to develop a classification algorithm for identifying the land use categories of blocks of digital MSS data. The classification algorithm was derived from a training set of 314 blocks and tested on a set of 310 blocks. The overall accuracy of the classifier was found to be 83.5% on seven land use categories

    ANTICANCER ACTIVITY OF POLYMERIC NANOPARTICLES CONTAINING ETOPOSIDE USING ALBINO RATS AS EXPERIMENTAL ANIMAL MODEL

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    Objective: Etoposide is a potent anticancer drug and a major limiting factor that hinders therapeutic use as its high levels of systemic circulation often associated with various off-target effects, particularly cardiotoxicity. The present study focuses on the evaluation of the anticancer activity of optimized etoposide nanoparticles compared with marketed etoposide formulation in experimental animal models.Methods: Albino rats (180–200 g) were used for the study. The anticancer effect of the formulated etoposide nanoparticles was evaluated by induction of hepatocellular carcinoma (HCC). The animals housed in cages and kept on a 12 h light/dark cycle. Following the acclimatization for 1 week, HCC will be induced in rats by adding 100 mg/L of diethylnitrosamine (DENA) in drinking water for 8 weeks. Drug treatment (etoposide [9 mg/kg] in 0.5 % carboxymethyl cellulose; p.o.) can be started at the end of 1 week after cancer induction and dose of 9 mg/kg of etoposide and lyophilized nanoparticles will be administered through oral route on 1, 7, 14, 21, and 28 days. Nanoformulations were evaluated in healthy rats, and anticancer activity was studied in DENA treated rats.Results: The results showed that the polymeric nanoparticles containing etoposide was screened for its anticancer activity by counting the liver nodules of rats with hematoxylin and eosin stain when comparing control and etoposide-treated group.Conclusion: The results of the study concluded that in rats treated with nanoformulations, the numbers of liver nodules were found to be significantly reduced

    Enhanced alpha-amylase production using Streptomyces gancidicus ASD by process optimization

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    845-852The present study was focused on purification and optimization of amylase from marine actinomycetes. Among 101 actinomycetes isolates from Andaman & Nicobar islands, Streptomyces sp gancidicus_ASD was isolated and further studied. The enzyme activity was studied at various physical parameters like temperature, pH, carbon source, Nitrogen source, metal ions, NaCl concentration etc. by maintaining all the factors with 100 ml of crude extract. Also, media optimization with response surface methodology was used to ameliorate the bioprocess economics. A central composite design was conducted to optimize the four selected factors. Statistical analyses of the data of model fitting were done by using Design expert 10.0 (stat-Ease). Results show a maximum predicted amylase yield of 11460.34 IU/ml when using 1.05% sucrose, 0.608% beef extract, 7.1 pH and 40.35 °C temperature. The predicted value is approximately 1.24-fold much higher than the original production (9248 IU/mL) determined by the conventional one-factor-at-a-time optimization method which can be applied in bioprocess for increased amylase yield

    Biopsy tract seeding in musculoskeletal sarcomas: myth or reality?

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    Background: It is a common practice in oncology in general and musculoskeletal oncology that the biopsy tract must be resected together with the tumor while performing limb-sparing surgery. Our study aims to assess the need for routine excision of biopsy scars in musculoskeletal malignancies by analyzing the presence of tumor in the biopsy tracts. Methods: We conducted a prospective study from January 2021 to April 2023, including 48 soft tissue and bone sarcoma patients. Neoadjuvant chemotherapy was administered to all cases of Ewings sarcoma and osteosarcoma. All of them underwent surgical resection with appropriate reconstruction. Biopsy tracts were sent separately and analyzed for tumor infiltration. Results: Two of the 48 patients included in the study had tumor deposits in their biopsy tracts. One patient with undifferentiated pleomorphic sarcoma and another patient with high-grade myxoid liposarcoma had tumor seeding in their biopsy tracts. Conclusions: The rate of biopsy tract seeding in our study was 4.2% (2 out of 48). Even though this might seem very less, it is still significant considering the rarity of bone and soft tissue sarcomas. Despite the low risk of tumor seeding, it is advisable to continue routinely excising the biopsy tract. Whether inappropriately placed biopsy tracts warrant an amputation instead of limb salvage is a question that will be best answered in the future with large-scale prospective randomized studies

    Gender-Related Differential Item Functioning of Mathematics Computation Items among Non-native Speakers of English

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    This study aimed at determining the presence of gender Differential Item Functioning (DIF) for mathematics computation items among non-native speakers of English, and thus examining the relationship between gender DIF and characteristics of mathematics computation items. The research design is a comparative study, where the boys form the reference group and the girls form the focal group. The software WINSTEPS, which is based on the Rasch model was used. DIF analyses were conducted by using the Mantel-Haenszel chi-square method with boys forming the reference group and girls forming the focal group. A total of 988 boys and 1381 girls in form two were selected from 34 schools, with 17 schools located in the Penang island, 12 schools in Penang mainland and five schools in Perak. Some 20 items were selected from the grade eight TIMSS 1999 and TIMSS 2003 released mathematics items. Findings revealed that seven items were flagged as DIF, where two were of moderate DIF and one as large DIF. Two DIF items assessed combined operation from the topics of fraction and negative numbers in the Number domain and the cognitive domain of lower-order thinking skills of Knowing favoured girls. One moderate DIF which assessed higher order thinking skills of Applying from the Algebra domain favoured boys. The findings trigger a possibility that computation items with one step operation, which assess lower-order thinking skills favour girls, while items that assess higher-order thinking skills favour boys

    STERILITY TESTING PROCEDURE OF OPHTHALMIC OCUSERT ACICLOVIR USED FOR TREATING HERPES SIMPLEX VIRUS

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      Objective: The present work focuses on sterility studies of prepared aciclovir ocusert which is so essential for ophthalmic preparations. According to Indian Pharmacopoeia, the sterility test was performed. Ocuserts are sterile preparations which are placed into cul-de-sac or conjunctival sac. Ophthalmic inserts offer many advantages over conventional dosage forms such as increased ocular residence time, possibility of releasing drugs at a slow and constant rate and accurate dosing. Ocuserts are formulated for treating external ocular diseases such as conjuctivitis, corneal ulcer, and keratoconjuctivitis. Ophthalmic preparations contaminated with microorganisms cause corneal damage and finally blindness, especially if the microorganism is Pseudomonas aeruginosa. Ophthalmic preparations should be manufactured in aseptic condition and to be sterilized before packing.Methods: According to Indian Pharmacopoeia, the official sterility test for ocusert was performed for detecting the presence of microbes. The selected F2 formulation which shows controlled drug release after 24 hrs was selected for the sterility test. The F2 formulation was subjected to ultraviolet radiation for sterilization. The sterilized ocusert and unsterilized ocusert were placed in fluid thioglycollate medium and incubated for 7 days at 20-25oC.Results: After 7 days of incubation, the sterilized ocusert shows no microbial growth and unsterilized ocusert shows microbial growth. The prepared aciclovir ocuserts were found to be sterile after the completion of official sterility test.Conclusion: The sterility studies conclude after 7 days of incubation period; there was no appearance of turbidity which indicates the prepared formulation F2 was found to be sterile
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