891 research outputs found

    Flame dynamics in the lift-off region of diesel jets

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    In this work, the large eddy simulation (LES) technique is employed to computationally model a lifted jet flame at conditions representative of those encountered in diesel engines. An unsteady flamelet progress variable (UFPV) model is used for turbulence/chemistry interactions. In the model, a look-up table of reaction source terms is generated as a function of mixture fraction Z, stoichiometric scalar dissipation rate χst, and progress variable Cst by solving the unsteady flamelet equations. In the present study, the progress variable is defined based on the sum of the major combustion products. A 37-species reduced chemical reaction mechanism for n-heptane is used to generate the UFPV libraries. The results show that ignition initiates at multiple points in the mixing layer around the jet, towards the edges of the jet, where the mixture fraction is rich, and the strain rates are within the ignition limits. These ignition kernels grow in time and merge to form a continuous flame front. Lift-off height is determined by the minimum axial distance from the orifice below whichthe local scalar dissipation rate does not favor ignition.Muhsin M. Ameen, Vinicio Magi, John Abrahamhttp://cfe.uwa.edu.au/news/acs2013http://www.anz-combustioninstitute.org

    Comparative study of Pap smear abnormalities in HIV infected and HIV non-infected women

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    Background: HIV positive women are more likely than HIV negative women to have cervical dysplasia. Incidence of HPV-related dysplasia increases as immune function declines. To analyse the prevalence of cervical dysplasia on papsmear among women affected with HIV and to compare with that of HIV negative women.Methods: The study period was of 6 months duration from December 2010 to May 2011. Cervical cytology specimen from HIV positive and HIV negative women who attended the OPD of Institute of Maternal and Child Health, Government Medical College, Kozhikode. Were collected after excluding known case of carcinoma cervix, post hysterectomy patients, patients with bleeding per vagina and also those with active genital tract infections.Results: A prospective study of 200 females (100 HIV positive and 100 HIV negative) was done in our hospital. Age range was between 36 and 50 years. PAP smear abnormality was obtained in 35% of the study group. Out of which 21% was seen in HIV positive patients and 14% in HIV negative patients. Prevalence of LSIL (low grade squamous intraepithelial lesion) was significantly higher among HIV positive patients. Abnormality was not associated with CD4 count, HIV status of husband or addictions of husband, not associated with number of partners of husband both in HIV positive and negative patients.Conclusions: PAP smear abnormality (overall), prevalence of LSIL was significantly higher among HIV positive patients. It was not associated with SES, age of first intercourse, number of partners of wife and other immunosuppressive status

    Negotiations 101: How to Conduct Principled Negotiations for Library Resources

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    This Negotiations 101 workshop is focused on providing a better foundation for librarians tasked with negotiating on behalf of their library. While many librarians are responsible for leading or providing support for negotiations with vendors, quite a few receive little to no formal training for doing so. To address this challenge, this three-hour online training will provide an introduction to negotiating theory followed by an exercise where the participants will be split into two smaller groups to prepare for a negotiation that will then be executed. Following the negotiation, participants will reflect on the results from this exercise together as a group. ACRL and SPARC co-hosted this workshop

    Dizajniranje i sinteza novih derivata tiofenkarbohidrazida, tienopirazola i tienopirimidina s antioksidativnim i antitumorskim djelovanjem

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    2-Amino-5-acetyl-4-methyl-thiophene-3-carboxylic acid ethyl ester (1) and 5-acetyl-2-amino-4-methylthiophene-3-carbohydrazide (2) were synthesized and used as starting materials for the synthesis of new series of 1-(5-amino-4-(3,5-dimethyl-1H-pyrazole-1-carbonyl)-3-methylthiophen-2-yl) ethanone (3a), 1-(5-amino-4-(4-chloro-3,5-dimethyl-1H-pyrazole-1-carbonyl)-3-methylthiophen-2-yl) ethanone (3b), 1-(4-methyl-2-amino-5-acetylthiophene-3-carbonyl) pyrazolidine-3,5-dione (4), (Z)-N\u27-(4-methyl-2-amino-5-acetylthiophene-3-carbonyl) formohydrazonic acid (5a), (Z)-ethyl-N\u27-(4-methyl-2-amino-5-acetylthiophene-3-carbonylformo hydrazonate (5b), 6-acetyl-3-amino-2,5-dimethylthieno2,3-dpyrimidin-4(3H)-one (8), 5-methyl-3-amino-2-mercapto-6-acetylthieno2,3-dpyrimidin-4(3H)-one (10) and 5-methyl-6-acetyl-2-thioxo-2,3-dihydrothieno2,3-dpyrimidin-4(1H)-one (12) as potential antioxidant and antitumor agents. Pharmacological results showed that compounds 6a, 6b, 8, 10 and 12 exhibited promising antitumor and antioxidant activity.Etilni ester 2-amino-5-acetil-4-metil-tiofen-3-karboksilne kiseline (1) i 5-acetil-2-amino-4-metiltiofen-3-karbohidrazid (2) sintetizirani su i upotrebljeni kao reaktanti u sintezi novih spojeva 1-(5-amino-4-(3,5-dimetil-1H-pirazol-1-karbonil)-3-metiltiofen-2-il) etanona (3a), 1-(5-amino-4-(4-klor-3,5-dimetil-1H-pirazol-1-karbonil)-3-metiltiofen-2-il) etanona (3b), 1-(4-metil-2-amino-5-acetiltiofen-3-karbonil) pirazolidin-3,5-diona (4), (Z)-N\u27-(4-metil-2-amino-5-acetiltiofen-3-karbonil) formohidrazonske kiseline (5a), (Z)-etil-N\u27-(4-metil-2-amino-5-acetiltiofen-3-karbonilformo hidrazonata (5b), 6-acetil-3-amino-2,5-dimetiltieno2,3-dpirimidin-4(3H)-one (8), 5-metil-3-amino-2-merkapto-6-acetiltieno2,3-dpirimidin-4(3H)-ona (10) i 5-metil-6-acetil-2-tiokso-2,3-dihidrotieno2,3-dpirimidin-4(1H)-ona (12) kao potencijalnih antioksidansa i citostatika. Farmakološka ispitivanja ukazuju na to da spojevi 6a, 6b, 8, 10 i 12 imaju značajno antitumorsko i antioksidativno djelovanje

    Circularly Polarised Hexagonal Patch Antenna With Polygonal Slot for RFID Applications

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    A compact single feed circularly polarized microstrip patch antenna for RFID applications is proposed. Antenna geometry includes a regular hexagon shaped patch with a polygonal slot embedded at the centre. The slot accounts for circular polarization and an area reduction of 22.5 %. It is fabricated on FR4 substrate with dielectric constant 4.4 and size 50 mm x 50 mm x 1.6 mm. The measured results include 10dB impedance bandwidth of 5.5 % at the center frequency of 2.42 GHz, a return loss of 32 dB, minimum axial ratio of 1.82 dB, axial ratio bandwidth of 7.5%, gain of 4.9 dBi with a broadside radiation characteristic for the RHCP antenna. These results are well in tune with the simulated results and the proposed design is suitable for RFID reader antenna applications

    A comprehensive TALEN-based knockout library for generating human induced pluripotent stem cell-based models for cardiovascular diseases

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    Rationale: Targeted genetic engineering using programmable nucleases such as transcription activator-like effector nucleases (TALENs) is a valuable tool for precise, site-specific genetic modification in the human genome. Objective: The emergence of novel technologies such as human induced pluripotent stem cells (iPSCs) and nuclease-mediated genome editing represent a unique opportunity for studying cardiovascular diseases in vitro. Methods and Results: By incorporating extensive literature and database searches, we designed a collection of TALEN constructs to knockout (KO) eighty-eight human genes that are associated with cardiomyopathies and congenital heart diseases. The TALEN pairs were designed to induce double-strand DNA break near the starting codon of each gene that either disrupted the start codon or introduced a frameshift mutation in the early coding region, ensuring faithful gene KO. We observed that all the constructs were active and disrupted the target locus at high frequencies. To illustrate the general utility of the TALEN-mediated KO technique, six individual genes (TNNT2, LMNA/C, TBX5, MYH7, ANKRD1, and NKX2.5) were knocked out with high efficiency and specificity in human iPSCs. By selectively targeting a dilated cardiomyopathy (DCM)-causing mutation (TNNT2 p.R173W) in patient-specific iPSC-derived cardiac myocytes (iPSC-CMs), we demonstrated that the KO strategy ameliorates the DCM phenotype in vitro. In addition, we modeled the Holt-Oram syndrome (HOS) in iPSC-CMs in vitro and uncovered novel pathways regulated by TBX5 in human cardiac myocyte development. Conclusions: Collectively, our study illustrates the powerful combination of iPSCs and genome editing technology for understanding the biological function of genes and the pathological significance of genetic variants in human cardiovascular diseases. The methods, strategies, constructs and iPSC lines developed in this study provide a validated, readily available resource for cardiovascular research

    Knowledge and attitudes about health research amongst a group of Pakistani medical students

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    Background Health research training is an important part of medical education. This study was conducted to assess the level of knowledge and attitudes regarding health research in a group of Pakistani medical students at Aga Khan University, Karachi. Methods It was a cross-sectional pilot study conducted among a group of Pakistani medical students. Through stratified random sampling, a pre-tested, structured and validated questionnaire was administered to 220 medical students. Knowledge and attitudes were recorded on a scale (graduated in percentages). Results Mean scores of students were 49.0% on knowledge scale and 53.7% on attitude scale. Both knowledge and attitudes improved significantly with increasing years of study in medical college [Regression coefficient 4.10 (p-value; 0.019) and 6.67 (p-value; \u3c 0.001) for knowledge and attitudes, respectively]. Conclusion Medical students demonstrate moderate level of knowledge and attitude towards health research. Intensive training in this regard is associated with significant improvement in knowledge and attitudes of students towards health research

    Case report: Malignant teratoma of the uterine corpus

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    <p>Abstract</p> <p>Background</p> <p>Teratomas are the commonest germ cell tumours and are most frequently found in the testes and ovary. Extragonadal teratomas are rare and mainly occur in midline structures. Uterine teratomas are extremely rare with only a few previous case reports, usually involving mature teratomas of the uterine cervix.</p> <p>Case Presentation</p> <p>We report an 82-year-old lady presenting with post-menopausal bleeding. Initial investigations revealed a benign teratoma of the uterus which was removed. Her symptoms persisted and a recurrent, now malignant, teratoma of the uterine corpus was resected at hysterectomy. Six months after surgery she relapsed with para-aortic lymphadenopathy and was treated with a taxane, etoposide and cisplatin-containing chemotherapy regimen followed by retroperitoneal lymph node dissection.</p> <p>Conclusion</p> <p>In this report we discuss the aetiology, diagnosis and management of uterine teratomas, and review previous case studies.</p

    Ethics, Nanobiosensors and Elite Sport: The Need for a New Governance Framework

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    Individual athletes, coaches and sports teams seek continuously for ways to improve performance and accomplishment in elite competition. New techniques of performance analysis are a crucial part of the drive for athletic perfection. This paper discusses the ethical importance of one aspect of the future potential of performance analysis in sport, combining the field of biomedicine, sports engineering and nanotechnology in the form of ‘Nanobiosensors’. This innovative technology has the potential to revolutionise sport, enabling real time biological data to be collected from athletes that can be electronically distributed. Enabling precise real time performance analysis is not without ethical problems. Arguments concerning (1) data ownership and privacy; (2) data confidentiality; and (3) athlete welfare are presented alongside a discussion of the use of the Precautionary Principle in making ethical evaluations. We conclude, that although the future potential use of Nanobiosensors in sports analysis offers many potential benefits, there is also a fear that it could be abused at a sporting system level. Hence, it is essential for sporting bodies to consider the development of a robust ethically informed governance framework in advance of their proliferated use

    Shrinking-Hole Colloidal Lithography: Self-Aligned Nanofabrication of Complex Plasmonic Nanoantennas

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    Plasmonic nanoantennas create locally strongly enhanced electric fields in so-called hot spots. To place a relevant nanoobject with high accuracy in such a hot spot is crucial to fully capitalize on the potential of nanoantennas to control, detect, and enhance processes at the nanoscale. With state-of-the-art nanofabrication, in particular when several materials are to be used, small gaps between antenna elements are sought, and large surface areas are to be patterned, this is a grand challenge. Here we introduce self-aligned, bottom-up and self-assembly based Shrinking-Hole Colloidal Lithography, which provides (i) unique control of the size and position of subsequently deposited particles forming the nanoantenna itself, and (ii) allows delivery of nanoobjects consisting of a material of choice to the antenna hot spot, all in a single lithography step and, if desired, uniformly covering several square centimeters of surface. We illustrate the functionality of SHCL nanoantenna arrangements by (i) an optical hydrogen sensor exploiting the polarization dependent sensitivity of an Au-Pd nanoantenna ensemble; and (ii) single particle hydrogen sensing with an Au dimer nanoantenna with a small Pd nanoparticle in the hot spot
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