2,450 research outputs found

    Preparation of proton exchange membrane by radiation-induced grafting method : Grafting of styrene onto poly(ethylene tetrafluoroethylene) copolymer films

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    Radiation induced grafting of styrene onto poly(ethylene-tetrafluoroethylene) (ETFE) copolymer film was carried out to prepare graft copolymer (ETFE-g-polystyrene) that can host sulfonic acid groups and form proton exchange membrane for polymer electrolyte fuel cell (PEFC). The effect of monomer concentration and type of solvent on the degree of grafting was investigated. The formation of graft copolymer film was confirmed by FTIR spectrum analysis

    Convenient Synthesis of Some New Bi-heterocycles conataining 3-Aminoquinazolin-4(3H)-one and 1,2,4-Triazole moieties

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    Dicarboxylic acids, thiosemicarbazides and methylanthranilate reacted to give methyl-2-(3-(5-mercapto-4-s-1,2,4-triazol-3-yl)-3-oxoalkylamino)benzoates 4. The laters, cyclized with hydrazine hydrate to give 3-amino-2-((5-mercapto-4 substitued-1,2,4-triazol-3-yl)alkyl)quinazolin-4(3H)-ones 5 which expected to have biological effects

    Spatial Statistical Analysis for Potential Transit Oriented Development (TOD) in Jakarta Metropolitan Region

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    Spatial planning on Transit Oriented Development (TOD) concerns with the integration between land use and transportation aspects. However, in some places, public transport management based on transit nodes such as train services which are not well- integrated, and causing spatial chaos, especially surrounding station areas. It is essential to prepare a public transportation plan by maximizing regional potential capacity with TOD model. The purpose of this paper is to identify and prioritize potential areas for TOD using spatial statistical analysis with combined models of Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) for Jakarta Metropolitan Regional (JMR), Indonesia. This paper employed two major indicators: main- and sub-indicators depending on relevant references. The weight of each indicator was determined by chosen experts. The result showed that some of the metro areas of Jakarta were highly suitable for TOD and indicated the characteristics of the development of urban areas. This paper’s outcome was useful in order to determine the potential location of TOD and was applicable to other areas within the same geographical conditions

    Vibration Signature of Normal and Notched Tooth Gear Pump

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    Gear pumps are critical devices in many industrial applications. An unexpected failure of the gear pump may cause significant effect on its performance. Consequently, there will be economic losses. As a result of that, fault diagnosis in gears has been the subject of intensive research. Vibration analysis has been used as an effective tool in machines diagnosis and in machinery maintenance decisions. As a rule, an increased vibration level is a warning form before failure or breakdown. By measuring and analyzing the gear pump vibration, it is possible to determine both the nature and severity of the defect, and hence predict the machine’s failure. The vibration signal of a gear pump carries the signature of the fault in the gears, and early fault detection of the gear pump is possible by analyzing the vibration signal using different signal processing techniques. This paper presents, experimentally, the external gear pump signature for normal and faulty gear pumps at different rotational speeds (1080, 1200, and 1439rpm). The considered faults herein are two different notches on one of the pump teeth— small notch and large notch. The paper concludes that features of the vibration are different with the notch shape and the rotational speed. The amplitude of vibration increases by increasing both rotational speed and notch size

    Single versus bilateral chordo-papillary apparatus preservation in mitral valve replacement: a hemodynamic study

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    Background: It has been postulated that disruption of the mitral valve apparatus at the time of mitral valve replacement (MVR) is a risk factor for postoperative ventricular dysfunction. The aim of this study was to evaluate the effect of single versus bilateral chordo-papillary preservation on the left ventricular function in comparison to no preservation. Methods: This study was conducted from 2015 to 2018 on sixty patients who had MVR. The patients were classified into group I included 20 patients who underwent MVR with complete excision of the subvalvular chordae and tips of papillary muscles, group II: included 20 patients who underwent MVR with preservation of posterior chordo-papillary apparatus, and group III: included 20 patients who underwent MVR with preservation of both posterior and anterior chordo-papillary apparatus. Results: There were 20 males (33.3%), and the mean age was 48.76± 8.91 years. Patients in group III were significantly older (37.15 ±4.92, 39.8 ± 5.49, and 57.25 ± 6.93 years in groups I, II, and III, respectively; p< 0.001). The left ventricular end-diastolic (5.40 ±0.34, 4.96 ± 0.43, and 4.44 ± 0.55 mm in group I, II and III, respectively, p<0.001) and end-systolic diameter (4.33 ±0.48, 3.58 ±0.43 and 3.20 ±0.43 mm in group I, II and III; respectively, p<0.001) were significantly reduced in partial and complete preservation groups after 6 months. Left ventricular ejection fraction improved in the bilateral preservation and partial preservation groups after 6 months (45.32 ±9.78, 56.79 ±10.14, and 56.60 ±11.68 % in groups I, II and III respectively, p<0.001). Mechanical ventilation was significantly longer in group I (24.10 ± 6.6, 16.80 ± 5.97, and 15.80 ± 5.24 hours in groups I, II and III, respectively, p<0.001) and the duration of ICU stay was significantly longer in group I (78.65 ± 15.32, 65.40 ± 14.21, and 60.20 ± 12.58 hours in groups I, II and III, respectively, p<0.001). Conclusion: Preservation of the annulo-papillary continuity may preserve left ventricular geometry and performance. Total preservation of chordae could be superior to partial preservation with better left ventricular remodeling and improvement in the left ventricular functions

    Preparation, structural characterization, antimicrobial and anticancer activities, DFT and molecular docking studies of a nano ferrocenyl Schiff base and its metal complexes

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    1319-1337An organometallic Schiff base (2-(1-((4-aminopyridin-3-yl)imino)ethyl)cyclopenta-2,4-dien-1-yl) (cyclopenta-2,4-dien-1-yl)iron (L) and eight transition metal complexes have been prepared by reacting 3,4-diaminopyridine with 2-acetylferrocene in 1:1 molar ratio for ligand formation and by reacting Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) chlorides with ligand in 1:1 molar ratio for complexes formation. All prepared compounds have been characterized by using elemental analysis (C, H, N, M), molar conductance, IR, UV-Vis, 1H-NMR, SEM and mass spectral analysis. Also, their TG and DTG behaviors have been studied. All complexes have an octahedral structure. The ligand coordinated to the metal ions through the nitrogen atoms of azomethine and amino groups. In addition, computational studies of the synthesized Schiff base ligand have been carried out by the DFT/B3LYP method. The antimicrobial activities of the ligand and its metal complexes have been studied by using different bacterial species [Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium] and fungal species included [Aspergillus fumigatus and Candida albicans]. Moreover, the prepared compounds have been evaluated for anticancer activities against breast cancer (MCF-7) and normal melanocytes (HFB-4) cell lines. Docking studies have been used to determine the probable binding mode between the ligand and its Cd(II) complex with the active site of 3HB5, 2HQ6 and 1GS4 receptors

    Effect of Web Opening Location on Fatigue Assessment of H Section Steel Beams

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    In the last decades, steel beams with web opening were used extensively as useful structural and architectural elements due to their many advantages. In this research, steel beams with web opening subjected to static loading were modelled using the multi-purpose finite element software ANSYS and the finite element results were compared with previous research. Then, steel beams with a single web opening subjected to fatigue loading were investigated numerically. The effect of changing the location of web opening on the fatigue assessment of H section steel beams with web opening was studied taking normal stress into account. It was clear that, normal stress fatigue life of the steel beams was affected significantly by changing web opening location along the beam span when compared to a beam with solid web while the beam span, opening size and steel section were kept constant. The most convenient location of web opening along the beam span was found to be at mid span

    The Response, Operability, and Type of Surgery Following Neoadjuvant Chemotherapy in Sudanese Patients with Locally Advanced Breast Cancer

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    Background:Neoadjuvant chemotherapy (NACT) treatment has become the standard treatment for locally advanced breast cancer (LABC) in many centers worldwide. Objectives: This study evaluates the short-term response of patients with LABC to NACT and its impact on operability and the type of surgery. Patients and Methods: This is a descriptive analytical hospital-based study including 147 patients with LABC who were presented to Plastic and Reconstructive Surgery Unit at Soba University hospital (SUH), between January 2012 and December 2014, and were treated with NACT. Clinical and pathological responses to neoadjuvant chemotherapy were evaluated according to Union for International Cancer Control criteria, operability, and the type of surgery performed was also recorded. Results: All patients were females, the mean age was 43 ± 7 years, of them 53.7% were pre-menopausal, 51% presented with a breast lump, 19.7% with nipple discharge, and 19% with skin changes and ulceration. The mean initial tumor size was 7 cm ± SD. Following NACT, complete clinical response was reported in 30 patients (20.4%), partial clinical response in 92(62.6%), stable clinical response in 20 (13.6%), and five (3.4%) had progressive clinical response. Initial smaller tumors (size < 5 cm) showed a better clinical response to NACT as 76.7% of complete clinical response was achieved.Pathological complete response was achieved in 25(17%) patients, pathological partial response in 102(74.1%), and pathological stable disease in 13(8.8%). Following NACT, breast conserving surgery was performed in 78(53.1%) patients, Modified Radical Mastectomy in 64(43.5%), 25 of them had Latissimus Dorsi, and five patients were not offered surgery as they developed progressive disease during the study period. Conclusion: Following NACT, it was possible to perform surgery in more than 96% of patients with LABC

    FLOATING RANITIDINE MICROPARTICULATES: DEVELOPMENT AND IN VITRO EVALUATION

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    Objective: Rapid and inconsistent gastrointestinal tract (GIT) transit could result in reduced drug efficiency and the need for frequent dose administration, which usually result in patients' incompliance. Ranitidine hydrochloride (RH), as a model drug is freely soluble, moisture sensitive drug with a short biological half-life (~2.5-3 h) and narrow absorption window in the initial part of the small intestine. The present study aimed to develop ranitidine floating multi-particulates (RFM) using melt granulation technique and investigation of the effect of lipids and additives on the physicochemical properties. Methods: RFM were prepared using Compritol® 888 ATO, glyceryl behenate, Cutina® HR, Cutina® GMS, hydrogenated castor oil, glyceryl monostearate, and beeswax as lipids and ethyl cellulose, Povidone® K 90 and Aerosil® 200 as release modifiers. The effect of the preparation method and additives, as well as storage for 6 mo at 40 °C, on floating and release characteristics were evaluated. Results: Size distribution indicated that the prepared formulations exhibited reasonably small floating micro particulates; more than 90% of the prepared microparticles were less than 710 µm. Hausner ratios and Carr's compressibility indices ranged from 1.17 to 1.29% and 14.54 to 22.4 %, respectively, and the angle of repose values was ≤40 °, indicating good flow properties. RFM containing Compritol® showed a relatively higher release properties compared to hydrogenated castor oil. Increasing the proportion of the fatty component was accompanied by retardation in RH release. The tested additives (PVP, ethyl cellulose, Aerosil®) resulted in different degrees of retardation of drug release. The percent-floating of RFM was almost 100% in all formulations with the exception of formulations prepared using glyceryl monostearate. FT-IR and DSC studies indicated the compatibility of the excipients with RH. Stability results revealed an insignificant change in RFM properties over 6 mo. Conclusion: The prepared microparticles exhibited optimum particle size, good compressibility, and flow properties. RFM containing Compritol® showed a relatively higher release properties compared to hydrogenated castor oil. Increasing the proportion of the fatty component was accompanied by retardation in RH release. The percent-floating of RFM was almost 100% in most formulations. FT-IR and DSC indicated good compatibility of the excipients with RH and insignificant change in RFM properties over 6 mo's storage

    The Performance of Cold-Formed Steel Members with Stiffened Perforations

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    CFS sections are usually supplied with openings to adapt construction services. Nevertheless, the area lowering in the web influences their strengths. If stiffeners are provided near the web openings, the reduction in flexural capacity could be recovered. Therefore, this paper introduces a study on the CFS section with stiffened perforations. A finite element (FE) analysis was accomplished. The numerical model was verified versus experimental and numerical tests from prior research and then utilized in performing parametric studies. The influence of circular openings with various sizes and various stiffener lengths on the flexural capacity was examined in the nonlinear analysis. Depending on the findings of the study, it has been determined that the introduction of stiffened openings into the CFS members will result in the restoration of the original flexural capacity
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