Stories From Islita Libre: Digital Spatial Storytelling as an Expression of Transnational and Immigrant Identities

In this essay, we examine the relationship between students’ spatial literacies of their neighborhoods and communities and their transnational identities, the latter which have complex, broad spatial and temporal dimensions. Over four months, we, a team of university researchers, led a series of instructional activities with a class of racially, ethnically, and linguistically diverse first- and second-generation immigrant students in an 11th grade introduction to research course. Here, we document the ways in which students learned about various data sources for inquiry to create digital, layered map-based stories about the factors that shape their (and others’) immigrant experiences in their local community. We offer two illustrations that respectively speak to how students\u27 spatial literacies of their neighborhoods included their self-positioning within the local sociopolitical landscape and at the same time, the signs and symbols they chose in their story maps reflected broader sociopolitical forces. We raise considerations and questions for educators who want to engage transnational and immigrant adolescent youth in multimodal, digital spatial storytelling

The preparation of thin film graded band gap solar cells

Thin film solar cells with a band gap graded inthe thickness direction were prepared by vacuumevaporation of various alloys of Cadmium Sulphide (CdS)and Cadmium Telluride (CdTe) onto glass substrates.Theoretical computer analyses were carried out andshow that a solar cell with a graded band gap surfacelayer ought to be a more efficient photovoltaic converterthan a conventional homojunction device. A vacuumevaporator capable of multiple simultaneous co-evaporationswas built and used initially to deposit only the CdSand CdTe films and subsequently mixed and gradedfilms of Cadmium Sulphide Telluride (CdSxTe 1-x).The composition of the mixed and graded films wascontrolled by a set of shutters built above the sources,rather than by the control of the temperature of thesources. The electronic properties of the films wereadjusted by co-evaporation of dopant materials suchas Cadmium (Cd), Indium (In) and Copper (Cu), andmeasured by Hall Effect measurements. The physicalproperties of the films such as the band gap, crystalphase and grain size were investigated by opticaltransmission measurements, X-ray analysis and scanningelectron microscopy respectively. Finally, p-n junctionswith n-type graded band gap surface layers on topof either pure p-type CdTe films or mixed p-typeCdS0.5Te0.5 films were prepared. However, thephotoresponse of these structures was low, probablydue to very short minority carrier life-times, lackof low resistance contacts and cross diffusion ofdopant materials. Nevertheless, the characteristicsof individual materials and the spectral responseof the devices indicated that if these problems couldbe solved, a successful solar cell could be made

Acute or chronic stress induce cell compartment-specific phosphorylation of glucocorticoid receptor and alter its transcriptional activity in Wistar rat brain

Chronic stress and impaired glucocorticoid receptor (GR) feedback are important factors for the compromised hypothalamic–pituitary–adrenal (HPA) axis activity. We investigated the effects of chronic 21 day isolation of Wistar rats on the extrinsic negative feedback part of HPA axis: hippocampus (HIPPO) and prefrontal cortex (PFC). In addition to serum corticosterone (CORT), we followed GR subcellular localization, GR phosphorylation at serine 232 and serine 246, expression of GR regulated genes: GR, CRF and brain-derived neurotropic factor (BDNF), and activity of c-Jun N-terminal kinase (JNK) and Cdk5 kinases that phosphorylate GR. These parameters were also determined in animals subjected to acute 30 min immobilization, which was taken as ‘normal’ adaptive response to stress. In isolated animals, we found decreased CORT, whereas in animals exposed to acute immobilization, CORT was markedly increased. Even though the GR was predominantly localized in the nucleus of HIPPO and PFC in acute, but not in chronic stress, the expression of GR, CRF, and BDNF genes was similarly regulated under both acute and chronic stresses. Thus, the transcriptional activity of GR under chronic isolation did not seem to be exclusively dependent on high serum CORT levels nor on the subcellular location of the GR protein. Rather, it resulted from the increased Cdk5 activation and phosphorylation of the nuclear GR at serine 232 and the decreased JNK activity reflected in decreased phosphorylation of the nuclear GR at serine 246. Our study suggests that this nuclear isoform of hippocampal and cortical GR may be related to hypocorticism i.e. HPA axis hypoactivity under chronic isolation stress

Development, Optimization, and Comparison of Different Sample Pre-Treatments for Simultaneous Determination of Vitamin E and Vitamin K in Vegetables

The absence of vitamin E from the diet can lead to cardiovascular disease, cancer, cataracts, and premature aging. Vitamin K deficiency can lead to bleeding disorders. These fat-soluble vitamins are important nutritional factors that can be determined in different methods in vegetables. In this work, the simultaneous determination of α-tocopherol, α-tocopheryl acetate, phylloquinone, and menaquinone-4 by gas chromatography–mass spectrometry (GC–MS) has been optimized using both direct injection and solid phase microextraction (SPME). Three different sample pre-treatment approaches based on: (A) solid–liquid–liquid–liquid extraction (SLE–LLE), (B) SLE, and (C) SPME were then applied to extract the target analytes from vegetables samples using menaquinone as internal standard. All the procedures allowed the determination of the target analytes in onion, carrot, celery, and curly kale samples. Similar results were obtained with the three different approaches, even if the one based on SPME offers the best performance, together with a reduced use of solvent, time consumption, and experimental complexity, which makes it the preferable option for industrial applications

Chronic stress differentially affects antioxidant enzymes and modifies the acute stress response in liver of wistar rats.

Summary Clinical reports suggest close interactions between stressors, particularly those of long duration, and liver diseases, such as hepatic inflammation, that is proposed to occur via reactive oxygen species. In the present study we have used 21-day social isolation of male Wistar rats as a model of chronic stress to investigate protein expression/activity of liver antioxidant enzymes: superoxide dismutases (SODs), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GLR), and protein expression of their upstream regulators: glucocorticoid receptor (GR) and nuclear factor kappa B (NFkB). We have also characterized these parameters in either naive or chronically stressed animals that were challenged by 30-min acute immobilization. We found that chronic isolation caused decrease in serum corticosterone (CORT) and blood glucose (GLU), increase in NFkB signaling, and disproportion between CuZnSOD, peroxidases (CAT, GPx) and GLR, thus promoting H 2 O 2 accumulation and prooxidative state in liver. The overall results suggested that chronic stress exaggerated responsiveness to subsequent stressor at the level of CORT and GLU, and potentiated GLR response, but compromised the restoration of oxido-reductive balance due to irreversible alterations in MnSOD and GPx

Proučavanje stabilnosti prinosa kukuruza neparametrijskim metodama

High and stabile yield in different production environments is priority in maize breeding. New statistical methods are constantly being sought to accompany analysis of variance, in order to achieve more reliable hybrid assessment. In this study nonparametric stability analysis is applied in order to assess GxE interaction for yield of 36 commercial maize hybrids. The experiment was set up at five locations in Serbia for three years according to the Randomised complete block design in three replications. Yield stability of investigated genotypes was analysed by stability parameters Si (1), Si (2), Si (3), Si (6) TOP and RS. Analysis of variance identified highly significant F values for all experimental factors. Bredenkamp method confirmed the existence of non-crossover GxE interaction, for maize yield. Hybrid ZPH15 achieved the most stable yield based on parameters Si (1) and Si (2). According to parameter Si (3) it was ZPH5, while based on parameter Si (6) it was ZPH34. The highest overall yield achieved ZPH36 (11.18 t ha-1 ), which was quite unstable (rank 24 in parameters Si (1) and Si (2)), and very unstable (rank 34 in parameters Si (3) and Si (6)). The most stable hybrids had average yields. In total, the hybrid ZPH23 had the best average rank (15.93). Based on TOP parameter, ZPH36 had the best rank (yield), followed by ZPH11, ZPH20, ZPH21 and ZPH9. However, RS parameter revealed that ZPH21 was the most stable hybrid, so taking into account both TOP and RS parameters this is the most productive and the most stable hybrid. Based on this research, TOP and RS are the best parameters for selecting new maize hybrids for production in particular environment. In case of identical TOP value, the genotype with the lowest RS value should be selected. The parameters Si (1), Si (2), Si (3) and Si (6) can be used as alternative methods for the selection of genotypes with moderate yield and high stability.U ovom radu primenjena je neparametarska analiza stabilnosti kako bi se procenila GxE interakcija za prinos 36 hibrida kukuruza. Eksperiment je postavljen na pet lokacija u Srbiji u trajanju od tri godine po potpuno slučajnom blok dizajnu (RCBD) u tri ponavljanja. Stabilnost prinosa ispitivanih genotipova analizirana je parametrima stabilnosti Si (1), Si (2), Si (3), Si (6), TOP i RS. Hibrid ZPH15 je postigao najstabilniji prinos na osnovu parametara Si (1) i Si (2), prema parametru Si (3) ZPH5, dok je na osnovu parametra Si (6) to bio ZPH34. Najrodniji hibrid ukupno u ogledu bio je ZPH36 sa prosečnim prinosom od 11,180 t/ha, koji je na osnovu ranga parametara Si (1) i Si (2) bio dosta nestabilan (rang 24), a na osnovu ranga parametara Si (3) i Si(6) veoma nestabilan (rang 34). Najstabilniji hibridi imali su prinos oko proseka. Ukupno, najbolji prosečan rang imao je hibrid ZPH 23 (15,93). Na osnovu TOP parametra najbolji rang (prinos) imao je ZPH36, a zatim ZPH11, ZPH20, ZPH21 i ZPH9. Međutim, RS parametar je pokazao da je ZPH21 najstabilniji hibrid, tako da je uzimajući u obzir i TOP i RS parametre ovo najproduktivniji i najstabilniji hibrid. Na osnovu ovog istraživanja, od svih posmatranih neparametarskih parametara, parametri TOP i RS pokazali su se kao najbolji za odabir novih hibrida kukuruza za gajenje u određenom regionu. U slučaju identične TOP vrednosti, treba izabrati genotip sa najnižom RS vrednošću, dok se parametri Si (1), Si (2), Si (3) i Si (6) mogu koristiti kao alternativne metode za selekciju genotipova sa umerenim prinosom i visokom stabilnošću

Evaluation of two-dimensional dose distributions for pre-treatment patient-specific IMRT dosimetry

Background. The accuracy of dose calculation is crucial for success of the radiotherapy treatment. One of the methods that represent the current standard for patient-specific dosimetry is the evaluation of dose distributions measured with an ionization chamber array inside a homogeneous phantom using gamma method. Nevertheless, this method does not replicate the realistic conditions present when a patient is undergoing therapy. Therefore, to more accurately evaluate the treatment planning system (TPS) capabilities, gamma passing rates were examined for beams of different complexity passing through inhomogeneous phantoms. Materials and methods. The research was performed using Siemens Oncor Expression linear accelerator, Siemens Somatom Open CT simulator and Elekta Monaco TPS. A 2D detector array was used to evaluate dose distribution accuracy in homogeneous, semi-anthropomorphic and anthropomorphic phantoms. Validation was based on gamma analysis with 3%/3mm and 2%/2mm criteria, respectively. Results. Passing rates of the complex dose distributions degrade depending on the thickness of non-water equivalent material. They also depend on dose reporting mode used. It is observed that the passing rate decreases with plan complexity. Comparison of the data for all set-ups of semi-anthropomorphic and anthropomorphic phantoms shows that passing rates are higher in the anthropomorphic phantom. Conclusions. Presented results raise a question of possible limits of dose distribution verification in assessment of plan delivery quality. Consequently, good results obtained using standard patient specific dosimetry methodology do not guarantee the accuracy of delivered dose distribution in real clinical cases

Fibroblastic niches prime T cell alloimmunity through Delta-like Notch ligands.

Alloimmune T cell responses induce graft-versus-host disease (GVHD), a serious complication of allogeneic bone marrow transplantation (allo-BMT). Although Notch signaling mediated by Delta-like 1/4 (DLL1/4) Notch ligands has emerged as a major regulator of GVHD pathogenesis, little is known about the timing of essential Notch signals and the cellular source of Notch ligands after allo-BMT. Here, we have shown that critical DLL1/4-mediated Notch signals are delivered to donor T cells during a short 48-hour window after transplantation in a mouse allo-BMT model. Stromal, but not hematopoietic, cells were the essential source of Notch ligands during in vivo priming of alloreactive T cells. GVHD could be prevented by selective inactivation of Dll1 and Dll4 in subsets of fibroblastic stromal cells that were derived from chemokine Ccl19-expressing host cells, including fibroblastic reticular cells and follicular dendritic cells. However, neither T cell recruitment into secondary lymphoid organs nor initial T cell activation was affected by Dll1/4 loss. Thus, we have uncovered a pathogenic function for fibroblastic stromal cells in alloimmune reactivity that can be dissociated from their homeostatic functions. Our results reveal what we believe to be a previously unrecognized Notch-mediated immunopathogenic role for stromal cell niches in secondary lymphoid organs after allo-BMT and define a framework of early cellular and molecular interactions that regulate T cell alloimmunity