Educational leadership in an age of accountability : a reflective essay

There are qualities of educational leaders that will lead them to success. A leader can use these qualities to improve the student achievement in a building, the self-concepts of the students and the teachers, and their own professional capacity. Four of these critical elements include the ability to develop a positive culture and climate, the ability to develop leaders within an organization, their ability to think systemically and systematically, and the integrity of their character

Central Nervous System Extracellular Matrix as a Therapeutic Bioscaffold for Central Nervous System Injury

Traumatic central nervous system (CNS) injuries lack effective treatment options and typically result in irrecoverable tissue damage and lifelong neurologic impairment. An ideal therapeutic would provide structural support for axonal regrowth as well as modulate the default secondary injury associated with CNS injuries. Extracellular matrix (ECM) bioscaffolds derived by decellularization promoted functional remodeling in numerous non-CNS applications; however, there has been minimal investigation of this technology in the CNS. The objectives of this work were to evaluate the tissue specific properties of CNS-ECM in terms of (1) hydrogel characteristics and biochemical composition, (2) neurotrophic potential, and (3) ability to alter the innate immune response. Bioscaffolds composed of CNS-ECM were formed into injectable solutions that polymerize to form hydrogels at body temperature. Hydrogels derived from CNS-ECM were compared to a hydrogel form of a non-CNS ECM, urinary bladder matrix (UBM-ECM), using compositional analyses for retained ECM molecules, mechanical assessments for rheological and turbidimetric properties, and multiphoton microscopy to visualize in-vitro three-dimensional neurite outgrowth. ECM hydrogels from both tissue sources had mechanical properties similar to native CNS and supported three-dimensional neurite outgrowth. CNS-ECM and UBM-ECM bioscaffold mediated alteration of the innate immune and neural stem cell response was interrogated in-vitro using macrophages and spinal cord stem cells (SPCs). While all ECM scaffolds evaluated decreased astrocyte differentiation, only UBM-ECM increased SPC neuronal differentiation. Bioscaffolds derived from both CNS and non-CNS tissue sources promoted a pro-repair macrophage phenotype as demonstrated through immunofluorescent results. Finally, CNS-ECM bioscaffolds were compared to UBM-ECM in a rat model of contusion spinal cord injury. Macrophage polarization was evaluated over 4 weeks and a histologic evaluation of the lesion site completed. While the ECM bioscaffolds did not improve functional recovery, pro-repair macrophages were found closely associated with the ECM injection sites. This body of work demonstrates CNS-ECM bioscaffolds can be isolated and are capable of minimally invasive injection, supporting neurite extension in-vitro, and modulating macrophage and stem cell responses. Future research is necessary to determine the added benefits that can be obtained when this technology is combined with others known to be beneficial for CNS tissue repair

U.S. Manufacturing and an Emerging Mexico

This paper offers a vision of the future of trade in manufactured products between Mexico and the United States. This vision is formed from a study of the 1970 and 1985 trade patterns of OECD countries. The vision accounts directly for the proximity of Mexico and the United States, and also for the continuing wage gap between Mexico and the United States. The vision accounts indirectly for the declining level of trade barriers and for the technological improvements that are probable in a liberalized Mexico. Based on the OECD trade patterns, an emerging Mexico will present U.S. export opportunities that are a significant fraction of current U.S. production of transportation equipment, chemicals and machinery. But Mexican exports are likely to displace a substantial amount of U.S. production of apparel, footwear, pottery and leather products. This vision which is formed using 1985 data does not offer an entirely accurate description of the changes in trade between Mexico and the United States that have occurred between 1985 and 1992. It is possible that the vision is defective, but it is also possible that the Mexican liberalization is incomplete, is in its infancy, and is still under serious threat of reversal.

Symptoms induced by transgenic expression of p23 from Citrus tristeza virus in phloem-associated cells of Mexican lime mimic virus infection without the aberrations accompanying constitutive expression

[EN] Citrus tristeza virus (CTV) is phloem restricted in natural citrus hosts. The 23-kDa protein (p23) encoded by the virus is an RNA silencing suppressor and a pathogenicity determinant. The expression of p23, or its N-terminal 157-amino-acid fragment comprising the zinc finger and flanking basic motifs, driven by the constitutive 35S promoter of cauliflower mosaic virus, induces CTV-like symptoms and other aberrations in transgenic citrus. To better define the role of p23 in CTV pathogenesis, we compared the phenotypes of Mexican lime transformed with p23-derived transgenes from the severe T36 and mild T317 CTV isolates under the control of the phloem-specific promoter from Commelina yellow mottle virus (CoYMV) or the 35S promoter. Expression of the constructs restricted to the phloem induced a phenotype resembling CTV-specific symptoms (vein clearing and necrosis, and stem pitting), but not the non-specific aberrations (such as mature leaf epinasty and yellow pinpoints, growth cessation and apical necrosis) observed when p23 was ectopically expressed. Furthermore, vein necrosis and stem pitting in Mexican lime appeared to be specifically associated with p23 from T36. Phloem-specific accumulation of the p23158-209(T36) fragment was sufficient to induce the same anomalies, indicating that the region comprising the N-terminal 157 amino acids of p23 is responsible (at least in part) for the vein clearing, stem pitting and, possibly, vein corking in this host.We thank Dr B. Ding for providing a construct with the phloem-specific promoter from CoYMV, and J. E. Peris, J. Juarez and M. T. Gorris for their excellent technical assistance. N.S. was supported by a PhD fellowship from the Instituto Valenciano de Investigaciones Agrarias (IVIA). This research was supported by grants AGL2009-08052, co-financed by Fondo Europeo de Desarrollo Regional-MICINN, and Prometeo/2008/121 from the Generalitat Valenciana.Soler, N.; Fagoaga García, CC.; López Del Rincón, C.; Moreno, P.; Navarro, L.; Flores Pedauye, R.; Peña Garcia, L. (2015). Symptoms induced by transgenic expression of p23 from Citrus tristeza virus in phloem-associated cells of Mexican lime mimic virus infection without the aberrations accompanying constitutive expression. Molecular Plant Pathology. 16(4):388-399. https://doi.org/10.1111/mpp.12188S38839916

River by Design: Essays on the Boise River, 1915-2015

River by Design marks 100 years since the Boise River emerged as an engineering sensation with the dedication of Arrowrock Dam. Sequenced like a tour with stops in Boise, Garden City, Eagle, Caldwell, and Parma, these essays collectively search for the politics and cultural values that drive engineering design.https://scholarworks.boisestate.edu/fac_books/1450/thumbnail.jp

Compressed collagen and decellularized tissue: novel components in a pipeline approach for the study of cancer metastasis

Metastasis is a complex process which is difficult to study and model. Experimental ingenuity is therefore essential when seeking to elucidate the biological mechanisms involved. Typically, in vitro models of metastasis have been overly simplistic, lacking the characteristic elements of the tumour microenvironment, whereas in vivo models are expensive, requiring specialist resources. Here we propose a pipeline approach for the study of cell migration and colonization, two critical steps in the metastatic cascade.We used a range of extracellular matrix derived contexts to facilitate a progressive approach to the observation and quantification of cell behaviour in 2D, 3D and at border zones between dimensions. At the simplest level, cells were set onto collagen-coated plastic or encapsulated within a collagen matrix. To enhance this, a collagen compression technique provided a stiffened, denser substrate which could be used as a 2D surface or to encapsulate cells. Decellularized tissue from the chorioallantoic membrane of the developing chicken embryo was used to provide a more structured, biologically relevant extracellular matrix-based context in which cell behaviour could then be compared with its in vivo counterpart.Cell behaviour could be observed and quantified within each context using standard laboratory techniques of microscopy and immunostaining, affording the opportunity for comparison and contrast of behaviour across the whole range of contexts. In particular, the temporal constraints of the in vivo CAM were removed when cells were cultured on the decellularized CAM, allowing for much longer-term cell colonization and cell-cell interaction.Together the assays within this pipeline provide the opportunity for the study of cell behaviour in a replicable way across multiple environments. The assays can be set up and analysed using easily available resources and standard laboratory equipment. We believe this offers the potential for the detailed study of cell migration and colonization of tissue, essential steps in the metastatic cascade. Also, we propose that the pipeline could be used in the wider arena of cell culture in general with the increasingly more complex contexts allowing cell behaviours and interactions to be explored in a stepwise fashion in an integrated way

3D extracellular matrix microenvironment in bioengineered tissue models of primary pediatric and adult brain tumors.

Dynamic alterations in the unique brain extracellular matrix (ECM) are involved in malignant brain tumors. Yet studies of brain ECM roles in tumor cell behavior have been difficult due to lack of access to the human brain. We present a tunable 3D bioengineered brain tissue platform by integrating microenvironmental cues of native brain-derived ECMs and live imaging to systematically evaluate patient-derived brain tumor responses. Using pediatric ependymoma and adult glioblastoma as examples, the 3D brain ECM-containing microenvironment with a balance of cell-cell and cell-matrix interactions supports distinctive phenotypes associated with tumor type-specific and ECM-dependent patterns in the tumor cells\u27 transcriptomic and release profiles. Label-free metabolic imaging of the composite model structure identifies metabolically distinct sub-populations within a tumor type and captures extracellular lipid-containing droplets with potential implications in drug response. The versatile bioengineered 3D tumor tissue system sets the stage for mechanistic studies deciphering microenvironmental role in brain tumor progression

Extracellular matrix hydrogels from decellularized tissues: structure and function

Extracellular matrix (ECM) bioscaffolds prepared from decellularized tissues have been used to facilitate constructive and functional tissue remodeling in a variety of clinical applications. The discovery that these ECM materials could be solubilized and subsequently manipulated to form hydrogels expanded their potential in vitro and in vivo utility; i.e. as culture substrates comparable to collagen or Matrigel, and as injectable materials that fill irregularly-shaped defects. The mechanisms by which ECM hydrogels direct cell behavior and influence remodeling outcomes are only partially understood, but likely include structural and biological signals retained from the native source tissue. The present review describes the utility, formation, and physical and biological characterization of ECM hydrogels. Two examples of clinical application are presented to demonstrate in vivo utility of ECM hydrogels in different organ systems. Finally, new research directions and clinical translation of ECM hydrogels are discusse

Extracellular matrix-derived hydrogels for dental stem cell delivery

Decellularized mammalian extracellular matrices (ECM) have been widely accepted as an ideal substrate for repair and remodelling of numerous tissues in clinical and pre-clinical studies. Recent studies have demonstrated the ability of ECM scaffolds derived from site-specific homologous tissues to direct cell differentiation. The present study investigated the suitability of hydrogels derived from different source tissues: bone, spinal cord and dentine, as suitable carriers to deliver human apical papilla derived mesenchymal stem cells (SCAP) for spinal cord regeneration. Bone, spinal cord, and dentine ECM hydrogels exhibited distinct structural, mechanical, and biological characteristics. All three hydrogels supported SCAP viability and proliferation. However, only spinal cord and bone derived hydrogels promoted the expression of neural lineage markers. The specific environment of ECM scaffolds significantly affected the differentiation of SCAP to a neural lineage, with stronger responses observed with spinal cord ECM hydrogels, suggesting that site-specific tissues are more likely to facilitate optimal stem cell behavior for constructive spinal cord regeneration