5 research outputs found

    Non-Zeeman Circular Polarization of Molecular Rotational Spectral Lines

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    We present measurements of circular polarization from rotational spectral lines of molecular species in Orion KL, most notably 12CO (J=2 - 1), obtained at the Caltech Submillimeter Observatory with the Four-Stokes-Parameter Spectra Line Polarimeter. We find levels of polarization of up to 1 to 2% in general, for 12CO (J=2 - 1) this level is comparable to that of linear polarization also measured for that line. We present a physical model based on resonant scattering in an attempt to explain our observations. We discuss how slight differences in scattering amplitudes for radiation polarized parallel and perpendicular to the ambient magnetic field, responsible for the alignment of the scattering molecules, can lead to the observed circular polarization. We also show that the effect is proportional to the square of the magnitude of the plane of the sky component of the magnetic field, and therefore opens up the possibility of measuring this parameter from circular polarization measurements of Zeeman insensitive molecules.Comment: 30 pages, 7 figures; accepted for publication in the Ap

    Comparison of Human Amniotic, Chorionic, and Umbilical Cord Multipotent Mesenchymal Stem Cells Regarding Their Capacity for Differentiation Toward Female Germ Cells

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    Placenta harbors a plentiful source of various cells with stem cells or stem-like cell properties, which can be used in therapeutic procedures and research. Mesenchymal stem cells (MSCs) have attracted much attention due to their specific differentiation potential and tolerogenic properties. MSCs have been isolated from different parts of placenta; however, in this study, we isolated MSCs from amnion and chorion membrane, as well as umbilical cord (Wharton's jelly [WJ]) and compared their capacity regarding differentiation toward female germ cells under influence of 10 ng/mL BMP4. All placenta samples were collected from delivering mothers by normal cesarean section and cells were isolated by different methods. Results showed that all isolated cells were mostly positive for the MSC markers CD73, CD166, and CD105, and minimally reacted with CD34 and CD45 (hematopoietic markers). After differentiation induction using third passage cultured cells, immunocytochemistry staining showed that cells were positive for germline cell-related genes Ssea4, Oct4, and Ddx4, and oocyte-related gene Gdf9. RT-qPCR results indicated that human chorion MSCs (hCMSCs) had a greater potential to be differentiated into female germline cells. Moreover, the results of this study indicate that human umbilical cord MSCs originated from either male or female umbilical cord have the same differentiation potential into female germline cells. We recommend that for presumptive application of MSCs for infertility treatment and research, hUMSCs are best candidates due to their higher differentiation potential, ease of proliferation and expansion, and low immunogenicity. Copyrigh

    Poucevanje in ucenje besedisca: Katere so uspesne in neuspesne strategije po mnenju ucencev angleskega jezika

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    Vocabulary constitutes an essential part of every language-learning endeavour and deserves scholarly attention. The objective of the present study was three-fold: 1) exploring Iranian English language learners’ Vocabulary Learning Strategies (VLSs), 2) examining language learners’ perceptions of vocabulary learning, and 3) exploring Iranian English language teachers’ Vocabulary Teaching Strategies (VTSs). In total, 145 intermediate learners of English as a foreign language, consisting of 114 males and 31 females aged 15 to 27, participated in the study. The triangulated data were collected using three tools: questionnaires, interviews, and class observations. Sixty-seven learners (31 females and 36 males) filled out a 56-statement questionnaire, adopted and adapted from Takac (2008) and translated into Persian. The questionnaire comprised two parts, enquiring as to the learners’ VLSs and the teachers’ VTSs. The findings indicated that females and males differed significantly in their reported VLSs and their teachers’ use of various VTSs. Additionally, 78 learners were interviewed as to their perceptions of effective and ineffective VLSs as well as VTSs. The findings revealed that the most effective VLSs were reported to be: a) reciting, repeating and listening to words, b) using words, and c) memorising words while the most effective VTSs revolved around: a) explanation, b) repetition, and c) dictation. The observations also confirmed the findings obtained via the questionnaire and interviews. In general, the findings are indicative of the limited repertoire of vocabulary acquisition techniques employed by Iranian EFL learners, hence the need for strategy training in how to acquire vocabulary. (DIPF/Orig.

    Germline cells derived from mesenchymal stem cells, with the focus on Wharton's jelly

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    Previous attempts have indicated that mesenchymal stem cells (MSCs) are a valuable source and candidate and new approach for tissue engineering and reproductive medicine. MSCs have this potential to be induced and differentiated in an appropriate in vivo and in vitro condition toward various cell lineages and then they can be applied in cell therapies and clinical applications. During recent two decades, various sources have demonstrated they are a great source for MSCs, including bone marrow, the human umbilical cord as well as Wharton's jelly. Due to discarding after birth, easily accessible cells and less ethical concerns, these cells have attracted more and more scientists' attention. Infertility and reproduction diseases have provided special opportunity to examine the efficiency of MSCs in this kind of application. Based on recent investigations, MSCs embedded in Wharton's jelly tissue are more appealing for cell therapies, especially in infertility treatment purposes. So, differentiation of MSCs embedded in Wharton's jelly tissue into germ layer cells for cell-based therapy purposes is now under intensive study

    Highly efficient remediation of chlorpyrifos and malachite green by an SBA-15 incorporated guar gum-grafted-poly (acrylic acid)/cobalt ferrite matrix for water purification

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    The Santa Barbara Amorphous-15-guar gum-grafted-poly (acrylic acid)/cobalt ferrite (SBA-15-GG-g-PAA/CoFe2O4) mesoporous adsorbent was prepared by graft copolymerization of acrylic acid (AA) onto guar gum (GG) in the Santa Barbara Amorphous-15 (SBA-15) substrate presence, followed by incorporating CoFe2O4 magnetic nanoparticles (MNPs). Diverse analyses were conducted to identify the prepared mesoporous adsorbent’s chemical and morphological properties, thermal resistance, magnetic characteristics, surface area, and porosity. Based on the magnetic hysteresis loops, the mesoporous adsorbent rendered ferromagnetic behavior. According to TGA, it has char yields of 72 wt% at 800 °C and superparamagnetic behavior (Ms of 3.22 emu.g−1). The crystalline structure and cubic phases of CoFe2O4 MNPs in the GG-g-PAA amorphous matrix were demonstrated by XRD. The CoFe2O4 MNP formation with partial aggregations onto smooth, nonporous, and regular surfaces of the GG was depicted by FESEM images. Also, the precisely-arranged hexagonal structure with cylindrical pores of SBA-15 was authenticated by FESEM images. Additionally, the SBA-15 substrate has increased the BET surface area of the prepared mesoporous adsorbent to 40.55 m2/g, which is higher than the composite without SBA-15 mesoporous silica. Several experimental setups were used to evaluate the effectiveness of adsorption, including pH of the medium (4–9), Adsorbent dosage (0.003–0.02 g), Interaction time (1–25 min), and Initial pollutant concentration (50–400 mg/L). Using 0.003 g of mesoporous adsorbent at 25 °C, chlorpyrifos (CPF) and malachite green (MG) had maximum adsorption capacities (Qmax) of 909.1 mg/g and 1000.0 mg/g, respectively. In this study, the Langmuir isotherm model fitted the adsorption data perfectly withRMG2 = 0.9987 andRCPF2 = 0.9994, and the pseudo-second-order model explained the adsorption kinetics with RMG2 = 0.9644 and RCPF2 = 0.9923. MG and CPF adsorption to the SBA-15-GG-g-PAA/CoFe2O4 mesoporous adsorbent was successful due to hydrogen bonds, exchange interactions, diffusion, and entrapment in the hydrogel network. In addition to the three-dimensional structure, the mesoporous adsorbent has available adsorption sites for reactive molecules. The reusability of the SBA-15-GG-g-PAA/CoFe2O4 was perused and showed that the mesoporous adsorbent can be separated efficiently and retrieved in three sequential cycles without considerable diminution in the adsorption efficiency
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