200 research outputs found

    The Effect of Using Various Magnetic Materials on Diesel Engines using Biodiesel Fuel

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    One of method to improve engine performance and reduce fuel consumption is to use exposure to magnetic fields in the fuel lines. Several studies have proven that magnetic field exposure can improve diesel engine performance. This research aims to test the performance of a diesel engine using fuels that are given a magnetic field from 3 types of permanent magnets, namely magnets made from Neodymium Iron Boron (NdFeB), Aluminum Nickel Cobalt (AlNiCo), and Ferrite (Fe). Performance tests on the Yanmar TF85MH diesel engine include power and torque. The fuel used in this research is Biodiesel B20. The results showed that neodymium magnets (NdFeB) are the best magnets of the 3 types of magnets tested with an average increase in power of 2.30%, an average increase in torque of 2.35%

    Studi Experimental Penggunaan Venturi Scrubber dan Cyclonic Separator Untuk Meningkatkan Kinerja pada Sistem Exhaust Gas Recirculation (EGR) dalam Menurunkan NOX pada Motor Diesel

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    Salah satu cara yang efektif untuk mengurangi NOX adalah dengan menggunakan metode Exhaust Gas Recirculation (EGR). Dengan metode EGR, oksigen yang masuk ke ruang bakar akan berkurang sehingga NOX dapat diturunkan dengan signifikan, akan tetapi power dari mesin tersebut juga akan berkurang dan Particulate Matter (PM) akan naik secara signifikan. Dalam penelitian ini dibahas penggunaan EGR yang telah di optimalkan dengan penambahan venturi scrubber dan cyclonic separator, tujuannya mengurangi NOX tanpa meningkatkan PM. Hasil pengujian menunjukkan NOX turun sebesar 48.89% dan PM turun dari 69,87%Β  menjadi 9.87%

    Development and validation of stability indicating method for determination of sertraline following ICH guidlines and its determination in pharmaceuticals and biological fluids

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    <p>Abstract</p> <p>Background</p> <p>Sertraline is a well known antidepressant drug which belongs to a class called selective serotonin reuptake inhibitor. Most published methods do not enable studying the stability of this drug in different stress conditions.</p> <p>Results</p> <p>Two new methods were developed for the determination of sertraline (SER). Both methods are based on coupling with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in borate buffer of pH 7.8 and measuring the reaction product spectrophotometrically at 395 nm (Method I) or spectrofluorimetrically at 530 nm upon excitation at 480 nm (Method II). The response-concentration plots were rectilinear over the range 2-24 ΞΌg/mL and 0.25-5 ΞΌg/mL for methods I and II respectively with LOD of 0.18 ΞΌg/mL and 0.07 ΞΌg/mL, and LOQ of 0.56 ΞΌg/mL and 0.21 ΞΌg/mL for methods I and II, respectively.</p> <p>Conclusion</p> <p>Both methods were applied to the analysis of commercial tablets and the results were in good agreement with those obtained using a reference method. The fluorimetric method was further applied to the in vivo determination of SER in human plasma. A proposal of the reaction pathway was presented. The spectrophotometric method was extended to stability study of SER. The drug was exposed to alkaline, acidic, oxidative and photolytic degradation according to ICH guidelines. Moreover, the method was utilized to investigate the kinetics of oxidative degradation of the drug. The apparent first order rate constant and t<sub>1/2 </sub>of the degradation reaction were determined.</p

    Mutations underlying 3-Hydroxy-3-Methylglutaryl CoA Lyase deficiency in the Saudi population

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    BACKGROUND: 3-Hydroxy-3-Methylglutaric aciduria (3HMG, McKusick: 246450) is an autosomal recessive branched chain organic aciduria caused by deficiency of the enzyme 3-Hydroxy-3-Methylglutaryl CoA lyase (HL, HMGCL, EC 4.1.3.4). HL is encoded by HMGCL gene and many mutations have been reported. 3HMG is commonly observed in Saudi Arabia. METHODS: We utilized Whole Genome Amplification (WGA), PCR and direct sequencing to identify mutations underlying 3HMG in the Saudi population. Two patients from two unrelated families and thirty-four 3HMG positive dried blood spots (DBS) were included. RESULTS: We detected the common missense mutation R41Q in 89% of the tested alleles (64 alleles). 2 alleles carried the frame shift mutation F305fs (-2) and the last two alleles had a novel splice site donor IVS6+1G>A mutation which was confirmed by its absence in more than 100 chromosomes from the normal population. All mutations were present in a homozygous state, reflecting extensive consanguinity. The high frequency of R41Q is consistent with a founder effect. Together the three mutations described account for >94% of the pathogenic mutations underlying 3HMG in Saudi Arabia. CONCLUSION: Our study provides the most extensive genotype analysis on 3HMG patients from Saudi Arabia. Our findings have direct implications on rapid molecular diagnosis, prenatal and pre-implantation diagnosis and population based prevention programs directed towards 3HMG

    Utility of certain nucleophilic aromatic substitution reactions for the assay of pregabalin in capsules

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    <p>Abstract</p> <p>Background</p> <p>Pregabalin (PG) is an anticonvulsant, analgesic and anxiolytic drug. A survey of the literature reveals that all the reported spectrophotometric methods are either don't offer high sensitivity, need tedious extraction procedures, recommend the measurement of absorbance in the near UV region where interference most probably occurs and/or use non specific reagent that don't offer suitable linearity range.</p> <p>Results</p> <p>Two new sensitive and simple spectrophotometric methods were developed for determination of pregabalin (PG) in capsules. Method (I) is based on the reaction of PG with 1,2-naphthoquinone-4-sulphonate sodium (NQS), yielding an orange colored product that was measured at 473 nm. Method (II) is based on the reaction of the drug with 2,4-dinitrofluorobenzene (DNFB) producing a yellow product measured at 373 nm. The different experimental parameters affecting the development and stability of the reaction product in methods (I) and (II) were carefully studied and optimized. The absorbance-concentration plots were rectilinear over the concentration ranges of 2-25 and 0.5-8 ΞΌg mL<sup>-1 </sup>for methods (I) and (II) respectively. The lower detection limits (LOD) were 0.15 and 0.13 ΞΌg mL<sup>-1 </sup>and the lower quantitation limits (LOQ) were 0.46 and 0.4 ΞΌg mL<sup>-1 </sup>for methods (I) and (II) respectively.</p> <p>Conclusion</p> <p>The developed methods were successfully applied to the analysis of the drug in its commercial capsules. The mean percentage recoveries of PG in its capsule were 99.11 Β± 0.98 and 100.11 Β± 1.2 (n = 3). Statistical analysis of the results revealed good agreement with those given by the comparison method. Proposals of the reaction pathways were postulated.</p

    Strategies to diagnose ovarian cancer: new evidence from phase 3 of the multicentre international IOTA study

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    Background: To compare different ultrasound-based international ovarian tumour analysis (IOTA) strategies and risk of malignancy index (RMI) for ovarian cancer diagnosis using a meta-analysis approach of centre-specific data from IOTA3. Methods: This prospective multicentre diagnostic accuracy study included 2403 patients with 1423 benign and 980 malignant adnexal masses from 2009 until 2012. All patients underwent standardised transvaginal ultrasonography. Test performance of RMI, subjective assessment (SA) of ultrasound findings, two IOTA risk models (LR1 and LR2), and strategies involving combinations of IOTA simple rules (SRs), simple descriptors (SDs) and LR2 with and without SA was estimated using a meta-analysis approach. Reference standard was histology after surgery. Results: The areas under the receiver operator characteristic curves of LR1, LR2, SA and RMI were 0.930 (0.917–0.942), 0.918 (0.905–0.930), 0.914 (0.886–0.936) and 0.875 (0.853–0.894). Diagnostic one-step and two-step strategies using LR1, LR2, SR and SD achieved summary estimates for sensitivity 90–96%, specificity 74–79% and diagnostic odds ratio (DOR) 32.8–50.5. Adding SA when IOTA methods yielded equivocal results improved performance (DOR 57.6–75.7). Risk of Malignancy Index had sensitivity 67%, specificity 91% and DOR 17.5. Conclusions: This study shows all IOTA strategies had excellent diagnostic performance in comparison with RMI. The IOTA strategy chosen may be determined by clinical preference

    Angiogenesis in a human neuroblastoma xenograft model: mechanisms and inhibition by tumour-derived interferon-Ξ³

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    Tumour progression in neuroblastoma (NB) patients correlates with high vascular index. We have previously shown that the ACN NB cell line is tumorigenic and angiogenic in immunodeficient mice, and that interferon-Ξ³ (IFN-Ξ³) gene transfer dampens ACN tumorigenicity. As IFN-Ξ³ represses lymphocyte-induced tumour angiogenesis in various murine models and inhibits proliferation and migration of human endothelial cells, we have investigated the antiangiogenic activity of tumour-derived IFN-Ξ³ and the underlying mechanism(s). In addition, we characterised the tumour vasculature of the ACN xenografts, using the chick embryo chorioallantoic membrane assay. We show that the ACN/IFN-Ξ³ xenografts had a lower microvessel density and less in vivo angiogenic potential than the vector-transfected ACN/neo. The vascular channels of both xenografts were formed by a mixed endothelial cell population of murine and human origin, as assessed by the FICTION (fluorescence immunophenotyping and interphase cytogenetics) technique. With respect to ACN/neo, the ACN/IFN-Ξ³ xenografts showed more terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling-positive human and murine endothelial cells, suggesting that inhibition of angiogenesis by IFN-Ξ³ was dependent on the induction of apoptosis, likely mediated by nitric oxide. Once the dual origin of tumour vasculature is confirmed in NB patients, the xenograft model described here will prove useful in testing the efficacy of different antiangiogenic compounds

    The Onconeural Antigen cdr2 Is a Novel APC/C Target that Acts in Mitosis to Regulate C-Myc Target Genes in Mammalian Tumor Cells

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    Cdr2 is a tumor antigen expressed in a high percentage of breast and ovarian tumors and is the target of a naturally occurring tumor immune response in patients with paraneoplastic cerebellar degeneration, but little is known of its regulation or function in cancer cells. Here we find that cdr2 is cell cycle regulated in tumor cells with protein levels peaking in mitosis. As cells exit mitosis, cdr2 is ubiquitinated by the anaphase promoting complex/cyclosome (APC/C) and rapidly degraded by the proteasome. Previously we showed that cdr2 binds to the oncogene c-myc, and here we extend this observation to show that cdr2 and c-myc interact to synergistically regulate c-myc-dependent transcription during passage through mitosis. Loss of cdr2 leads to functional consequences for dividing cells, as they show aberrant mitotic spindle formation and impaired proliferation. Conversely, cdr2 overexpression is able to drive cell proliferation in tumors. Together, these data indicate that the onconeural antigen cdr2 acts during mitosis in cycling cells, at least in part through interactions with c-myc, to regulate a cascade of actions that may present new targeting opportunities in gynecologic cancer

    Single cell dissection of plasma cell heterogeneity in symptomatic and asymptomatic myeloma

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    Multiple myeloma, a plasma cell malignancy, is the second most common blood cancer. Despite extensive research, disease heterogeneity is poorly characterized, hampering efforts for early diagnosis and improved treatments. Here, we apply single cell RNA sequencing to study the heterogeneity of 40 individuals along the multiple myeloma progression spectrum, including 11 healthy controls, demonstrating high interindividual variability that can be explained by expression of known multiple myeloma drivers and additional putative factors. We identify extensive subclonal structures for 10 of 29 individuals with multiple myeloma. In asymptomatic individuals with early disease and in those with minimal residual disease post-treatment, we detect rare tumor plasma cells with molecular characteristics similar to those of active myeloma, with possible implications for personalized therapies. Single cell analysis of rare circulating tumor cells allows for accurate liquid biopsy and detection of malignant plasma cells, which reflect bone marrow disease. Our work establishes single cell RNA sequencing for dissecting blood malignancies and devising detailed molecular characterization of tumor cells in symptomatic and asymptomatic patients
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