283 research outputs found

    A Novel Study of Electrospun Nanofibers Morphology as a Function of Polymer Solution Properties

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    Electrospinning is a process of production fibers with diameters ranging from the submicron down to the nanometer size by applying a high voltage to a polymer solution. The important parameters in the morphology of electrospun polymer fibers are polymer structure, polymer solution properties, processing conditions, and ambient parameters. In the present work electrospinning of polyacrylonitrile (PAN) has been attempted to generate uniform nanofibers without beads. Electrospinning was performed at various concentrations ranging from 4 to 18 w/v%. The effects of polymer solution properties on electrospinnability of the PAN/DMF solutions have investigated. Fiber morphology was observed under a scanning electron microscopy (SEM). For the polymer electrospun from low concentration (Be4. The relationship between solution viscosity and its concentration is in the form: Ξ· 0.0205C4.16 and relation between the diameter of electro-spun the PAN nanofiber and solution concentration is in the form: d 0.0326C3.45. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3514

    Relationship between Single Walled Carbon Nanotubes Individual Dispersion Behavior and Properties of Electrospun Nanofibers

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    The dispersion stability behavior of single walled carbon nanotube (SWCNT) has important effects on morphological and mechanical properties of SWCNT/polymer composite nanofibers. The effects of SWCNTs incorporation on the morphological and structural developments and the relation between this develop-ments and mechanical properties of the polyacrylonitrile (PAN) nanofibers were demonstrated. The uni-form, stable dispersion and well oriented SWCNT within the PAN matrix were achieved through using polyvinylpyrrolidone (PVP) as dispersing agent. Our data indicate that with increasing the amount of SWCNT (from 0 to 2 wt %), the average nanofiber diameter was increased from 163±19 nm to 307±34 nm. The analysis of the mechanical properties of the composite nanofibers displays that they exhibit an im-provement in the tensile strength of ∼172% from 3.93±0.45 MPa to 10.74±1.03 MPa, and the elastic modu-lus was increased by ~885% from 61.39±15.58 GPa to 605.08±65.55 GPa, as compared to the pure electro-spun nanofibers. The optimal SWCNT concentration for electrospun nanofibers with better morphological and mechanical properties is ~2 wt %. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3516

    A Novel Study of Electrospun Nanofibers Morphology as a Function of Polymer Solution Properties

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    Electrospinning is a process of production fibers with diameters ranging from the submicron down to the nanometer size by applying a high voltage to a polymer solution. The important parameters in the morphology of electrospun polymer fibers are polymer structure, polymer solution properties, processing conditions, and ambient parameters. In the present work electrospinning of polyacrylonitrile (PAN) has been attempted to generate uniform nanofibers without beads. Electrospinning was performed at various concentrations ranging from 4 to 18 w/v%. The effects of polymer solution properties on electrospinnability of the PAN/DMF solutions have investigated. Fiber morphology was observed under a scanning electron microscopy (SEM). For the polymer electrospun from low concentration (Be4. The relationship between solution viscosity and its concentration is in the form: Ξ· 0.0205C4.16 and relation between the diameter of electro-spun the PAN nanofiber and solution concentration is in the form: d 0.0326C3.45. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3514

    Fabrication of Homogeneous Multi-Walled Carbon Nanotube/ Poly (Vinyl Alcohol) Composite Nanofibers for Microwave Absorption Application

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    Poly (vinyl alcohol) (PVA) / sodium dodecyl sulfate (SDS) / multi walled carbon nanotubes (MWCNT) camposite nanofibers with various MWCNT contents (up to 10 wt%) were fabricated by electrospinning process and their microwave absorption properties were evaluated by a vector network analyzer in the frequency range of 8 – 12 GHz (X-band) at room temperature. The uniform, stable dispersion and well oriented MWCNT within the PVA matrix were achieved through using SDS as dispersing agent. The SEM analysis of the nanofibers samples revealed that the deformation of the nanofibers increases with increasing MWCNT concentration. Very smooth surface of the composite electrospun nanofibers even for the nanofibers with concentration of 10 wt MWCNT have been successfully prepared because of the high stability dispersion of MWCNT. It was observed that absorption microwave properties improved with increasing in the loading levels of MWCNT. Finally, the PVA/SDS/MWCNT composite nanofibers sample with the 10 wt content of MWCNT has shown the reflection loss of 15 dB at the frequency of 8 GHz. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3558

    Modified artificial diet for rearing of tobacco budworm, Helicoverpa armigera using the Taguchi method and Derringer’s desirability function

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    With the aim to improve the mass rearing feasibility of tobacco budworm, Helicoverpa armigera HΓΌbner (Lepidoptera: Noctuidae), design of experimental methodology using Taguchi orthogonal array was applied. To do so, the effect of 16 ingredients of an artificial diet including bean, wheat germ powder, Nipagin, ascorbic acid, formaldehyde, oil, agar, distilled water, ascorbate, yeast, chloramphenicol, benomyl, penicillin, temperature, humidity, and container size on some biological characteristics of H. armigera was evaluated. The selected 16 factors were considered at two levels (32 experiments) in the experimental design. Among the selected factors, penicillin, container size, formaldehyde, chloramphenicol, wheat germ powder, and agar showed significant effect on the mass rearing performance. Derringer's desirability function was used for simultaneous optimization of mass rearing of tobacco budworm, H. armigera, on a modified artificial diet. Derived optimum operating conditions obtained by Derringer's desirability function and Taguchi methodology decreased larval period from 19 to 15.5 days (18.42 % improvement), decreased the pupal period from 12.29 to 11 days (10.49 % improvement), increased the longevity of adults from 14.51 to 21 days (44.72 % improvement), increased the number of eggs/female from 211.21 to 260, and increased egg hatchability from 54.2% to 72% (32.84 % improvement). The proposed method facilitated a systematic mathematical approach with a few well-defined experimental sets

    Development and Evaluation of Real-Time RT-PCR Test for Quantitative and Qualitative Recognition of Current H9N2 Subtype Avian Influenza Viruses in Iran

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    Avian influenza H9N2 subtype viruses have had a great impact on Iranian industrial poultry production economy since introduction in the country. To approach Rapid and precise identification of this viruses as control measures in poultry industry, a real time probe base assay was developed to directly detect a specific influenza virus of H9N2 subtype -instead of general detection of Influenza A viruses- which has been endemic over two last decades in the country. An Iranian avian influenza virus strain of A/Iran/chicken/772/1998 H9N2 subtype were selected as reference strain for of primers and probe designing. The high agreement value of 99% indicated that the devolved real time assay for detection of H9 subtype viruses could easily replace the conventional method of virus isolation particularly in investigation of viruses like national surveillance plan. The limit of detection was almost one EID50 which was the least real infectious unit could be detected. So it can be said that this sensitive assay provided a powerful tool to not to miss any significant viral biological activity neither in the host body nor in the environment. A high level of correlation coefficient (R2 = 0.998) also indicated a good correlation between Ct values and viral concentrations. , it can be conclude that the real time RT-PCR could be easily replace virus isolation in detection of H9N2 influenza viruses especially in large monitoring program. The ability in quantifying of the virus concentration extends usage of test in more accurate studies

    New report of two species of black fungus gnats (Dip.: Sciaridae) from Iran

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    A study on the arthropods associated with Agaricales macrofungi in the western Iranian province of Kermanshah during 2010-2011 led to the discovery of two black fungus gnat species of Corynoptera perpusilla Winnertz and Bradysia ocellaris (Comstock). Both sciarid species are here reported for the first time from Iran

    Changes in Blood microRNA Expression and Early Metabolic Responsiveness 21 Days Following Bariatric Surgery

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    Background: Early metabolic responses following bariatric surgery appear greater than expected given the initial weight loss and coincide with improvement in diabetes. We hypothesized that small non-coding microRNA changes might contribute to regulating mechanisms for metabolic changes and weight loss in patients with severe obesity and diabetes.Methods: Twenty-nine type 2 patients with severe obesity (mean BMI 46.2 kg/m2) and diabetes underwent Roux-en-Y gastric bypass (RYGB) surgery. Clinical measurements and fasting blood samples were taken preoperatively and at day 21 postoperatively. Normalization of fasting glucose and HbA1c following bariatric surgery (short-term diabetes remission) was defined as withdrawal of anti-diabetic medication and fasting glucose < 100 mg/dL (5.6 mmol/L) or HbA1c < 6.0%. MicroRNA expression was determined by quantitative polymerase chain reaction and tested for significant changes after surgery.Results: BMI decreased by 3.8 kg/m2 21 days postoperatively. Eighteen of 29 RYGB (62%) had short-term diabetes remission. Changes from pre- to post-surgery in 32 of 175 microRNAs were nominally significant (p < 0.05). Following multiple comparison adjustment, changes in seven microRNAs remained significant: miR-7-5p, let-7f-5p, miR-15b-5p, let-7i-5p, miR-320c, miR-205-5p, and miR-335-5p. Four pathways were over-represented by these seven microRNAs, including diabetes and insulin resistance pathways.Conclusion: Seven microRNAs showed significant changes 21 days after bariatric surgery. Functional pathways of the altered microRNAs were associated with diabetes-, pituitary-, and liver-related disease, with expression in natural killer cells, and pivotal intestinal pathology suggesting possible mechanistic roles in early diabetes responses following bariatric surgery

    546 Results from Phase Ib study of tebentafusp (tebe) in combination with durvalumab (durva) and/or tremelimumab (treme) in metastatic cutaneous melanoma (mCM)

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    BackgroundTebe, a T cell receptor fused to an anti-CD3 effector, can redirect T cells to target gp100+ cells and in Ph3, demonstrated overall survival (OS) benefit as monotherapy in metastatic uveal melanoma. In Ph2, any tumor shrinkage (44% of patients) was a better predictor of OS than response rate. In Ph1, Tebe had monotherapy activity in mCM, also a gp100+ tumor, with 1-year OS ~74% in PD-1 naΓ―ve mCM. A Ph1 dose escalation of tebe with durva (anti-PD-L1) and/or treme (anti-CTLA4) was conducted in pre-treated mCM [NCT02535078], with nearly all patients having prior PD1-treatment, and where recently reported therapies have 1-yr OS of ~55%.MethodsHeavily pre-treated HLA-A2+ mCM patients received weekly IV tebe alone (Arm 4) or with increasing doses of durva and/or treme (Arm 1–3) administered IV monthly starting day 15 of each cycle. Primary objective was to identify RP2D of combination therapy. Secondary objectives included adverse events (AE) and efficacy.Results112 pts received β‰₯1 tebe dose. Median age was 59, 77% were ECOG 0, and 37% were BRAFm (of which 71% received prior BRAFi/MEKi). 91% of pts were 2L+, while 74% were 3L+. 103 (92%) received prior PD-1 inhibitor, of which 87% also received prior ipilimumab. 43 pts received tebe + durva (Arm 1), 13 received tebe + treme (Arm 2), 29 received triplet therapy (Arm 3), and 27 received tebe alone (Arm 4). Maximum target doses of tebe (68 mcg) + durva (20 mg/kg) and treme (1 mg/kg) were tolerated. MTD was not formally identified for any arm. Two DLTs occurred: prolonged grade 3 rash (Arm 1) and grade 2 diarrhea leading to treatment delay (Arm 2). Related AEs that were Grade β‰₯3 or led to discontinuations were: 44%/0% (Arm 1), 23%/0% (Arm2), 38%/7% (Arm3), 26%/4% (Arm 4). There were no treatment-related deaths.In prior PD-1 pts, tumor shrinkage occurred in 36% and 1-yr OS was 68%. Of 51 evaluable PD-1 resistant pts (best response CR/PR/SD to prior PD1), tumor shrinkage occurred in 28% and 1-yr OS was 73% (figure 1). In 35 evaluable PD-1 refractory pts (prior best response PD), tumor shrinkage occurred in 49% and 1-yr OS was 61%. For 38 prior PD-1 pts who received β‰₯10mg/kg durva, 1-yr OS was 81%.Abstract 546 Figure 1% tumor change from baseline in evaluable patients with known response to prior PD1 exposureConclusionsTebe with anti-PD-L1 and/or anti-CTLA4 had an acceptable safety profile. Tebe + durva demonstrated durable tumor shrinkage and promising 1-yr OS rates in prior-PD1 treated mCM relative to recent reports.Trial RegistrationNCT02535078Ethics ApprovalThe institutional review board or independent ethics committee at each center approved the trial. The trial was conducted in accordance with the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines
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