211 research outputs found

    Dynamic refining control model for LD converter

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    A mathematical model for the dynamic refining control of the LD Converter is presented. Equations representing the reaction kinetics are formulated using the oxygen demand function. The amount of oxygen accumulated in LD Conver-ter, which is calculated from the oxygen balance by using exhaust gas data, corresponds to the amount of FeO, Fe203 and Mn0 in the slag during blowing. With the control of the refining reaction with oxygen balance carbon, phospho-rus and manganese contents of steel and the total iron content of slag at blow end were controlled at preferable levels and their fluctuations were remarkably reduced. The equations were coupled with appropriate thermal balance equations. The resulting set of non-linear first order equations have been numerically solved to predict the reaction path in the converter as a function of the operat-ing conditions like oxygen blowing rate, lance height, iron ore, limestone additions rates etc. With continuous on line data feeding from the converter facilities like sublance systems and waste gas analysers the entire conve-rter operation could be automated. The model works on a simple micro computer and could be easily incorporated on to the on-line control circuit of the Converter

    An explorative clinical study to evaluate the combined effect of Shiropichu, Sthanika Abhyanga, Salvana Upanaha Sweda and Balarishta in the management of Pakshaghata vis~a~vis Hemiplegia

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    Pakshaghata is one among the Vata Nanatmaja Vyadhi, characterised by loss of function either in right or left half of the body. Pakshaghata is also considered among the ailments of Madhyama Roga Marga. Signs and symptoms of Pakshaghata is similar to that of stroke with hemiplegia as the cardinal clinical feature. It makes the affected person physically disabled and reduces quality of life. Even though western science had moved for in acute management of stroke, it is very difficult to handle the residual effect of stroke which makes person physically and mentally debilitated. In case of managing residual cases, it depends on physiotherapy and exercises, which gives good results if combined with Ayurvedic treatments such as Abhyanga. Present study is a single group open clinical trial with pre and post-test design with a sample size of 30 subjects. Subjects were administered with Shiropichu, Sthanika Abhyanga, Salvana Upana Sweda for first 10 consecutive days and Shamanaaushadha for all 30 days. The results obtained on parameter muscle power, muscle tone, finger movements and deep tendon reflexes was statistically non-significant in the management of Pakshaghata vis-Ă -vis hemiplegia. The results obtained on parameter stroke specific quality of life scale showed statistically significant result with p value 0.005 in the management of Pakshaghata vis-Ă -vis hemiplegia. Hence, it was inferred that the intervention selected for the present study possess combined effect in improving the quality of life of individual affected with Pakshaghata vis-Ă -vis Hemiplegia

    Effect of Chelating Agents on Push-Out Bond Strength of NeoMTA Plus to Root Canal Dentin

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    Objective: To evaluate and compare the effect of 17% Ethylenediaminetetraacetic Acid (EDTA), 9% Etidronic acid (HEDP), and 7% Maleic acid (MA) on the push-out bond strength of NeoMTA Plus sealer to the coronal, middle, and apical thirds of root canal dentin. Material and Methods: Forty single-rooted human maxillary central incisors were selected and decoronated to 12 mm long root fragments. Working length was established and root canals were then enlarged up to rotary Protaper F3. After each instrumentation, the root canal was irrigated with 2.5% NaOCl. For the final irrigation regimen, the specimens were divided into 4 groups (n=10) and treated with EDTA, HEDP, MA or Saline. Root canals were coated with NeoMTA Plus sealer, and obturation was done with single cone obturation technique. Subsequently, three horizontal sections were taken from the coronal, middle and apical thirds of each specimen, and POBS was measured using a universal testing machine. The type of bond failures was assessed under a stereomicroscope. Statistical analysis was done with One-way ANOVA with Tukey’s Post hoc analysis. Results: MA and EDTA showed the highest POBS. There was no significant difference in bond strength between MA and EDTA (p>0.05). HEDP and Saline showed lower POBS. Among all the four groups, the coronal third showed the highest values, followed by middle and apical thirds. Conclusion: The type of chelating agent used during the root canal treatment significantly affects the bond strength of NeoMTA Plus to the root canal dentin

    Can the concentration of citric acid affects its cytotoxicity and antimicrobial activity?

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    Background: There has been no unanimity concerning the ideal concentration of citric acid for safe use in clinical practice. This study evaluated the cytotoxicity and the antibacterial activity in infected dentinal tubules of 10% and 1% citric acid (CA) solutions. Methods: The cytotoxicity of CA solutions in DMEM (diluted 1/10, 1/100) was assessed in L-929 fibroblasts. A broth macrodilution method (MIC and MBC) was used to assess CA antibacterial concentration. The antimicrobial activity of CA solutions was also evaluated after their final rinse inside root canals in previously Enterococcus faecalis-contaminated dentinal tubules. Ten infected dentine samples were rinsed for 5 min with 5% NaOCl and subsequently with 1% citric acid for 3 min. Another 10 were rinsed with 5% NaOCl and 10% citric acid for 3 min; the remaining four specimens were utilized as positive controls. Two uncontaminated specimens were used as negative controls. After LIVE/DEAD BacLight staining, the samples were assessed using CLSM to analyze the percentage of residual live and dead cells. Results: Both undiluted and diluted CA solutions showed severe toxicity; no changes from normal morphology were displayed when diluted 1/100. The MIC and MBC of CA were 6.25 mg/mL and 12.50 mg/mL, respectively. CA solutions demonstrated significantly low levels of bacterial counts than the positive control group, reporting a value of 9.3% for the 10% solution versus the 1% solution (35.2%). Conclusions: Despite its valuable antimicrobial properties, the cytotoxic effects of citric acid should be considered during endodontic treatment

    Correlation between CD4 counts of HIV patients and enteric protozoan in different seasons – An experience of a tertiary care hospital in Varanasi (India)

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    <p>Abstract</p> <p>Background</p> <p>Protozoan infections are the most serious among all the superimposed infections in HIV patients and claim a number of lives every year. The line of treatment being different for diverse parasites necessitates a definitive diagnosis of the etiological agents to avoid empirical treatment. Thus, the present study has been aimed to elucidate the associations between diarrhoea and CD4 counts and to study the effect of HAART along with management of diarrhoea in HIV positive patients. This study is the first of its kind in this area where an attempt was made to correlate seasonal variation and intestinal protozoan infestations.</p> <p>Methods</p> <p>The study period was from January 2006 to October 2007 wherein stool samples were collected from 366 HIV positive patients with diarrhea attending the ART centre, inpatient department and ICTC of S.S. hospital, I.M.S., B.H.U., Varanasi. Simultaneously, CD4 counts were recorded to assess the status of HIV infection vis-Ă -vis parasitic infection. The identification of pathogens was done on the basis of direct microscopy and different staining techniques.</p> <p>Results</p> <p>Of the 366 patients, 112 had acute and 254 had chronic diarrhea. The percentages of intestinal protozoa detected were 78.5% in acute and 50.7% in chronic cases respectively. Immune restoration was observed in 36.6% patients after treatment on the basis of clinical observation and CD4 counts. In 39.8% of HIV positive cases <it>Cryptosporidium </it>spp. was detected followed by <it>Microsporidia </it>spp. (26.7%). The highest incidence of intestinal infection was in the rainy season. However, infection with <it>Cyclospora </it>spp. was at its peak in the summer. Patients with chronic diarrhea had lower CD4 cell counts. The maximum parasitic isolation was in the patients whose CD4 cell counts were below 200 cells/ÎŒl.</p> <p>Conclusion</p> <p>There was an inverse relation between the CD4 counts and duration of diarrhea. <it>Cryptosporidium </it>spp. was isolated maximum among all the parasites in the HIV patients. The highest incidence of infection was seen in the rainy season.</p

    Genetic Anticipation Is Associated with Telomere Shortening in Hereditary Breast Cancer

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    There is increasing evidence suggesting that short telomeres and subsequent genomic instability contribute to malignant transformation. Telomere shortening has been described as a mechanism to explain genetic anticipation in dyskeratosis congenita and Li-Fraumeni syndrome. Since genetic anticipation has been observed in familial breast cancer, we aimed to study telomere length in familial breast cancer patients and hypothesized that genetic defects causing this disease would affect telomere maintenance resulting in shortened telomeres. Here, we first investigated age anticipation in mother-daughter pairs with breast cancer in 623 breast cancer families, classified as BRCA1, BRCA2, and BRCAX. Moreover, we analyzed telomere length in DNA from peripheral blood leukocytes by quantitative PCR in a set of 198 hereditary breast cancer patients, and compared them with 267 control samples and 71 sporadic breast cancer patients. Changes in telomere length in mother-daughter pairs from breast cancer families and controls were also evaluated to address differences through generations. We demonstrated that short telomeres characterize hereditary but not sporadic breast cancer. We have defined a group of BRCAX families with short telomeres, suggesting that telomere maintenance genes might be susceptibility genes for breast cancer. Significantly, we described that progressive telomere shortening is associated with earlier onset of breast cancer in successive generations of affected families. Our results provide evidence that telomere shortening is associated with earlier age of cancer onset in successive generations, suggesting that it might be a mechanism of genetic anticipation in hereditary breast cancer

    Acapsular Staphylococcus aureus with a non-functional agr regains capsule expression after passage through the bloodstream in a bacteremia mouse model

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    Selection pressures exerted on Staphylococcus aureus by host factors during infection may lead to the emergence of regulatory phenotypes better adapted to the infection site. Traits convenient for persistence may be fixed by mutation thus turning these mutants into microevolution endpoints. The feasibility that stable, non-encapsulated S. aureus mutants can regain expression of key virulence factors for survival in the bloodstream was investigated. S. aureus agr mutant HU-14 (IS256 insertion in agrC) from a patient with chronic osteomyelitis was passed through the bloodstream using a bacteriemia mouse model and derivative P3.1 was obtained. Although IS256 remained inserted in agrC, P3.1 regained production of capsular polysaccharide type 5 (CP5) and staphyloxanthin. Furthermore, P3.1 expressed higher levels of asp23/SigB when compared with parental strain HU-14. Strain P3.1 displayed decreased osteoclastogenesis capacity, thus indicating decreased adaptability to bone compared with strain HU-14 and exhibited a trend to be more virulent than parental strain HU-14. Strain P3.1 exhibited the loss of one IS256 copy, which was originally located in the HU-14 noncoding region between dnaG (DNA primase) and rpoD (sigA). This loss may be associated with the observed phenotype change but the mechanism remains unknown. In conclusion, S. aureus organisms that escape the infected bone may recover the expression of key virulence factors through a rapid microevolution pathway involving SigB regulation of key virulence factors.Fil: Suligoy Lozano, Carlos Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Díaz, Rocío E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Gehrke, Ana-katharina Elsa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Ring, Natalie. University of Edinburgh; Reino UnidoFil: Yebra, Gonzalo. University of Edinburgh; Reino UnidoFil: Alves, Joana. University of Edinburgh; Reino UnidoFil: Gómez, Marisa Ileana. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Wendler, Sindy. UniversitÀtsklinikum Jena Und Medizinische FakultÀt; AlemaniaFil: Fitzgerald, J. Ross. University of Edinburgh; Reino UnidoFil: Tuchscherr, Lorena. Jena University Hospital; AlemaniaFil: Löffler, Bettina. Jena University Hospital; AlemaniaFil: Sordelli, Daniel Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Noto Llana, Mariangeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Buzzola, Fernanda Roxana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; Argentin
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