212 research outputs found

    Fabrication of (Polymer Blend-magnesium Oxide) Nanoparticle and Studying their Optical Properties for Optoelectronic Applications

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    Nanocomposites used in many optical devices applications. This aims to preparation of new type of polymer and study their optical properties. The polyvinyl pyrrolidone-carboxymethyl cellulose blend and magnesium oxide nanocomposites have been fabricated. The nanocomposites are prepared for different concentrations of polymer blend and magnesium oxide nanoparticles. The optical properties of nanocomposites were studied. The experimental results showed that the absorbance, absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant and optical conductivity of (PVP-CMC) blend are increased with increase of the MgO nanoparticles concentration. The transmittance and energy band gap are decreased with increase of the MgO nanoparticles concentration. The nanocomposites have high absorbance in UV region which may be used for radiation shielding application

    Galaxy emission line classification using 3D line ratio diagrams

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    Two-dimensional (2D) line ratio diagnostic diagrams have become a key tool in understanding the excitation mechanisms of galaxies. The curves used to separate the different regions - HII-like or else excited by an active galactic nucleus (AGN) - have been refined over time but the core technique has not evolved significantly. However, the classification of galaxies based on their emission line ratios really is a multi-dimensional problem. Here we exploit recent software developments to explore the potential of three-dimensional (3D) line ratio diagnostic diagrams. We introduce a specific set of 3D diagrams, the ZQE diagrams, which separate the oxygen abundance and the ionisation parameter of HII region-like spectra, and which also enable us to probe the excitation mechanism of the gas. By examining these new 3D spaces interactively, we define a new set of 2D diagnostics, the ZE diagnostics, which can provide the metallicity of objects excited by hot young stars, and which cleanly separate HII region-like objects from the different classes of AGNs. We show that these ZE diagnostics are consistent with the key log[NII]/Hα\alpha vs. log[OIII]/Hβ\beta diagnostic currently used by the community. They also have the advantage of attaching a probability that a given object belongs to one class or to the other. Finally, we discuss briefly why ZQE diagrams can provide a new way to differentiate and study the different classes of AGNs in anticipation of a dedicated follow-up study.Comment: 21 pages, 15 figures, accepted for publication in ApJ. Due to size limitations, the supplementary STL file for the 3D-printable diagram is available here: http://www.mso.anu.edu.au/~fvogt/online_material.htm

    PVA/Chitosan/Silver Nanoparticles Electrospun Nanocomposites: Molecular Relaxations Investigated by Modern Broadband Dielectric Spectroscopy

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    In this study, we used broadband dielectric spectroscopy to analyze polymer nanofibers of poly(vinyl alcohol)/chitosan/silver nanoparticles. We also studied the effect of incorporating silver nanoparticles in the polymeric mat, on the chain motion dynamics and their interactions with chitosan nanofibers, and we calculated the activation energies of the sub-Tg relaxation processes. Results revealed the existence of two sub-Tg relaxations, the first gets activated at very low temperature (−90 °C) and accounts for motions of the side groups within the repeating unit such as –NH2, –OH, and –CH2OH in chitosan and poly(vinyl alcohol). The second process gets activated around −10 °C and it is thought to be related to the local main chain segments’ motions that are facilitated by fluctuations within the glycosidic bonds of chitosan. The activation energy for the chitosan/PVA/AgNPs nanocomposite nanofibers is much higher than that of the chitosan control film due to the presence of strong interactions between the amine groups and the silver nanoparticles. Kramers–Krönig integral transformation of the ε′′ vs. f spectra in the region of the chitosan Tg helped resolve this relaxation and displayed the progress of its maxima with increasing temperature in the regular manner

    Breast Cancer in Thi-Qar 2018, it's determinants, histopathological presentation and six years' time trends, A comparative study

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    Objectives : to assess  the soscio-demographic characteristics,  clinico-pathological presentations, and important determinant of breast cancer patients  counseling breast disease center in Thi-Qar 2018, to study and compare  the yearly time trend of breast cancer in Thi-Qar from 2013-2017. Methods: A cross sectional analytical design was used. all women presented with breast mass at defined age, at the time of study, were included. Results: About  (59.5%)of malignant masses were moderately differentiated and (32%) of them were poorly differentiated (8.5%) were well differentiated at the time of study, Also about half of patients presents at late stages, while only 10% at early stages , in other word. The age was strongly correlated factor and about 57.5% of the malignancies were above 45. Recommendations :  1.Further studies with different design permit longer duration, are required  and preferred to be follow-up type to determine the effect of confound risk factors as age, stress and radiation rather than defined ones, also studies required about response to therapy and follow the complication.  2.Regular programmed screening required to detect the cancer in the earlier stage, and facilitate the availability of screening tools at the health care centers and in  peripheries hospitals of Thi-Qar

    Breast Cancer in Thi-Qar 2018, it's determinants, histopathological presentation and six years' time trends, A comparative study

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    Objectives : to assess  the soscio-demographic characteristics,  clinico-pathological presentations, and important determinant of breast cancer patients  counseling breast disease center in Thi-Qar 2018, to study and compare  the yearly time trend of breast cancer in Thi-Qar from 2013-2017. Methods: A cross sectional analytical design was used. all women presented with breast mass at defined age, at the time of study, were included. Results: About  (59.5%)of malignant masses were moderately differentiated and (32%) of them were poorly differentiated (8.5%) were well differentiated at the time of study, Also about half of patients presents at late stages, while only 10% at early stages , in other word. The age was strongly correlated factor and about 57.5% of the malignancies were above 45. Recommendations :  1.Further studies with different design permit longer duration, are required  and preferred to be follow-up type to determine the effect of confound risk factors as age, stress and radiation rather than defined ones, also studies required about response to therapy and follow the complication.  2.Regular programmed screening required to detect the cancer in the earlier stage, and facilitate the availability of screening tools at the health care centers and in  peripheries hospitals of Thi-Qar

    Haematologic Parameters In Acute Promyelocytic Leukemia Patients Treated With ALL Trans- Retinoic acid

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    Background: Acute Promyelocytic Leukemia (APL) is commonly associated with disseminated intravascular coagulation (DIC) and early correction of coagulopathy is of vital importance. All Trans-Retinoic Acid (ATRA) is considered to be the drug of choice in the treatment of APL.  Objective: The work was conducted to 1- Identify patients with APL who show laboratory evidence of DIC. 2- Study the serial changes in haemostatic parameters in APL patients treated with ATRA and to compare their results with those treated with conventional chemotherapy without ATRA. Subjective and methods: In this prospective study (from October 2003 to October 2005), 44 newly diagnosed, untreated APL patients were included. ATRA plus chemotherapy – treated patients were 24 while 17 patients were treated with chemotherapy other than ATRA. For each patient, a full clinical evaluation was done and hematological investigations were accomplished at time of diagnosis and repeated on day 3 and 7 of therapy. Diagnosis of DIC was based on finding a positive D- dimer test with hypofibrinogenaemia with or without pathologically prolonged (PT and/or APTT). Results: In 44 newly diagnosed, untreated APL patients studied, the age range between 6-81 years with a median of 27 years. Male to female ratio was 1.3:1. Before treatment all patients had anemia, thrombocytopenia, and elevated level of D – dimer. DIC was present in all patients at time of diagnosis. All parameters that showed abnormal level at time of diagnosis had returned to normality within one week in ATRA treated group, indicating that DIC has essentially resolved. By contrast, those parameters remained abnormal even on day 7 in the chemotherapy treated group. Indicating that DIC was on going. Conclusion: ATRA therapy in APL patients is associated with rapid improvement of coagulopathy therefore , it is justified to be used from day one of the treatment

    Quantitative uptake of colloidal particles by cell cultures

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    The use of nanotechnologies involving nano- and microparticles has increased tremendously in the recent past. There are various beneficial characteristics that make particles attractive for a wide range of technologies. However, colloidal particles on the other hand can potentially be harmful for humans and environment. Today, complete understanding of the interaction of colloidal particles with biological systems still remains a challenge. Indeed, their uptake, effects, and final cell cycle including their life span fate and degradation in biological systems are not fully understood. This is mainly due to the complexity of multiple parameters which need to be taken in consideration to perform the nanosafety research. Therefore, we will provide an overview of the common denominators and ideas to achieve universal metrics to assess their safety. The review discusses aspects including how biological media could change the physicochemical properties of colloids, how colloids are endocytosed by cells, how to distinguish between internalized versus membrane-attached colloids, possible correlation of cellular uptake of colloids with their physicochemical properties, and how the colloidal stability of colloids may vary upon cell internalization. In conclusion three main statements are given. First, in typically exposure scenarios only part of the colloids associated with cells are internalized while a significant part remain outside cells attached to their membrane. For quantitative uptake studies false positive counts in the form of only adherent but not internalized colloids have to be avoided. pH sensitive fluorophores attached to the colloids, which can discriminate between acidic endosomal/lysosomal and neutral extracellular environment around colloids offer a possible solution. Second, the metrics selected for uptake studies is of utmost importance. Counting the internalized colloids by number or by volume may lead to significantly different results. Third, colloids may change their physicochemical properties along their life cycle, and appropriate characterization is required during the different stages.This work was supported by the European Commission (grant FutureNanoNeeds) grant agreement no. 604602 to WJP. NF acknowledges funding from the Lars Hiertas Minne Fundation (Sweden), SA, BP and IC acknowledge a fellowship from the Alexander von Humboldt Fundation (Germany). AE acknowledges Junta de Andalucía (Spain) for a Talentia Postdoc Fellowship, co-financed by the European Union Seventh Framework Programme, grant agreement no 267226. AHS acknowledges the Egyptian government (Ministry of Higher Education, Mission). The project was also supported by the Dr. Dorka-Stiftung (Germany) to PJ

    Potential Molecular Mechanisms of Rare Anti-Tumor Immune Response by SARS-CoV-2 in Isolated Cases of Lymphomas

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    Recently, two cases of complete remission of classical Hodgkin lymphoma (cHL) and follicular lymphoma (FL) after SARS-CoV-2 infection were reported. However, the precise molecular mechanism of this rare event is yet to be understood. Here, we hypothesize a potential anti-tumor immune response of SARS-CoV-2 and based on a computational approach show that: (i) SARS-CoV-2 Spike-RBD may bind to the extracellular domains of CD15, CD27, CD45, and CD152 receptors of cHL or FL and may directly inhibit cell proliferation. (ii) Alternately, upon internalization after binding to these CD molecules, the SARS-CoV-2 membrane (M) protein and ORF3a may bind to gamma-tubulin complex component 3 (GCP3) at its tubulin gamma-1 chain (TUBG1) binding site. (iii) The M protein may also interact with TUBG1, blocking its binding to GCP3. (iv) Both the M and ORF3a proteins may render the GCP2-GCP3 lateral binding where the M protein possibly interacts with GCP2 at its GCP3 binding site and the ORF3a protein to GCP3 at its GCP2 interacting residues. (v) Interactions of the M and ORF3a proteins with these gamma-tubulin ring complex components potentially block the initial process of microtubule nucleation, leading to cell-cycle arrest and apoptosis. (vi) The Spike-RBD may also interact with and block PD-1 signaling similar to pembrolizumab and nivolumab- like monoclonal antibodies and may induce B-cell apoptosis and remission. (vii) Finally, the TRADD interacting “PVQLSY” motif of Epstein-Barr virus LMP-1, that is responsible for NF-kB mediated oncogenesis, potentially interacts with SARS-CoV-2 M(pro), NSP7, NSP10, and spike (S) proteins, and may inhibit the LMP-1 mediated cell proliferation. Taken together, our results suggest a possible therapeutic potential of SARS-CoV-2 in lymphoproliferative disorders
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