Manipulating Light: Creating a Biomimetic Photonic Crystal Material Inspired by the Chameleon

The purpose of this project is to create a chameleon-inspired biomimetic material using guanine crystals and polydimethylsiloxane (PDMS) to form a tunable photonic crystal and then characterize the material. The method for developing this material is to first synthesize a photonic crystal made of a guanine microsphere lattice. Then embed the guanine lattice in PDMS. Since PDMS is an elastomer, it can be stretched to adjust the spacing between the guanine crystals. This should allow for the photonic crystal to be adjusted similarly to the way that the chameleon adjusts the photonic crystal in its skin by changing the spacing between the guanine particles. The material is characterized primarily through qualitative observations and scanning electron microscopy. It will be shown that the guanine microspheres are successfully synthesized. Two potential methods for embedding the guanine microspheres in PDMS are developed, experimented with, and explained. A third potential method is explored, but no experimentation was done with this method

Age-dependent alterations in spermatogenesis in itchy mice

Spermatogenesis is an intricate process in which spermatogonial stem cells divide and differentiate to produce mature sperm. This process strongly depends on protein turnover both in the developing germ cells and the supportive Sertoli cells, and recent evidence has demonstrated the role of the ubiquitin-proteasome system in this protein turnover in the testis. Itch, an E3 ligase important in the immune system, has been implicated in regulating the blood testis barrier. Although the specific role of Itch during spermatogenesis is not yet well understood, its ubiquitous expression and wide array of functional targets suggest multiple and tissue-specific roles. Here the testes of mice that lack Itch protein are evaluated at two developmental time points: peri-pubertal postnatal day (PND) 28 and adult PND 56. Itchy mice demonstrate an increased germ cell apoptotic index compared with wild type C57BL/6J mice at both PND 28 and PND 56. A corresponding 27% reduction in the total number of spermatid heads produced in PND 56 itchy mice was also evident. A histological evaluation of itchy mice revealed a delay in spermatogenesis at PND 28 and disorganization of late stage spermatids at PND 56. An analysis of several apoptotic markers revealed an age-dependent change in cleaved caspase 9, an intrinsic apoptosis mediator. The breeding success of the itchy mice was also significantly decreased, possibly due to a developmental defect. Taken together, these findings indicate that Itch is required for functional spermatogenesis, and that it may play differing cellular roles during development

Ready, Set, Communicate: Measuring Usability of Instructional Modules Designed to Improve Communications Skills of Students Studying Agricultural Sciences

Well-developed communications skills are essential to a proficient agricultural workforce. Online instruction via reusable learning modules (RLMs) is one way agricultural science faculty can provide their students with expert communications skills training. Although RLMs have many benefits, their value degrades rapidly if the learner cannot access or use the technology efficiently. Therefore, online instruction must be tested to ensure usability. The purpose of our study was to assess the usability of RLMs developed to bolster the communications skills of students studying in the agricultural sciences and provide guidance for future curricula and online instruction development. We used quantitative and qualitative data sources to assess the usability of three RLMs, according to N = 21 students. The usability metrics we assessed included learnability, navigation, video function, document access and readability, quiz and assignment practicality, and task difficulty. The RLMs garnered high usability scores from participants who had positive impressions and experiences completing them. Participants demonstrated an increase in confidence to perform communications skills and an increase in knowledge about communications after completing the modules. They thought embedded videos, documents, quizzes, and assignments were helpful in learning communications concepts. Some recommended improving navigation, document readability, and assignment details. Based on our findings, we recommend RLM developers embed short videos, printable handouts, and quizzes into RLMs, and include an overview of documents’ key points to guide reading. Participants’ positive feedback and willingness to engage with the RLMs suggests incorporating the RLMs into agricultural science courses will help students develop into science communicators

Children, civilianhood, and humanitarian securitization

In this paper, the influence of the construction of children as civilians over the processes of securitization in the US intervention in Somalia is examined. This is done through an analysis of the US print news media coverage of that event. The study employs two key theoretical frameworks: the first is the social understanding of civilianhood; and the second is the Copenhagen School’s theory of securitization. The work concludes that a failure to unpack the value of referent objects of security diminishes the insights that securitization theory can offer. The grammar of securitizing moves cannot be fully comprehended in instances of militarized humanitarian interventions, in particular, without this kind of analysis. Children as suffering civilians draw considerable attention from the world’s media and thus an investigation of their role in securitization can be highly informative

Morphological evidences indicate that the interference of cimetidine on the peritubular components is responsible for detachment and apoptosis of Sertoli cells

Cimetidine, referred as antiandrogenic agent, has caused alterations in the seminiferous tubules, including alterations in the peritubular tissue and death of myoid cells by apoptosis. Regarding the structural and functional importance of the peritubular tissue for the maintenance of Sertoli cells (SC), we purpose to investigate the SC-basement membrane interface, focusing the morphological features of SC and their interaction with the basement membrane in the affected tubules by cimetidine. Ten animals were distributed into two groups, control (CG) and cimetidine (CmG) which received saline solution and 50 mg of cimetidine per kg of body weight, respectively, for 52 days. The testes were fixed, dehydrated and embedded for analyses under light and transmission electron microscopy. Paraffin sections were submitted to the TUNEL method; sections of testes embedded in glycol methacrylate were submitted to PAS method and stained by H&E for morphological and quantitative analyses of Sertoli Cells. In the CmG, the SC nuclei were positive to the TUNEL method and showed typical morphological alterations of cell death by apoptosis (from early to advanced stages). A significant reduction in the number of Sertoli Cells was probably due to death of these cells by apoptosis. A close relationship between SC nuclear alterations (including a high frequency of dislocated nuclei from the basal portion) and damage in the peritubular tissue was observed. The ultrastructural analysis showed a parallelism between the gradual advancement of apoptotic process in SC and detachment of the anchoring sites (hemidesmosomes) of SC plasma membrane from the lamina densa. The presence of portions of lamina densa underlying the detached hemidesmosomes indicates a continuous deposition of lamina densa, resulting in the thickening of the basal lamina. The results indicate a possible disarrangement of the SC cytoskeleton, including the focal adhesion structure. These alterations are related to SC apoptosis and probably result from disturbs induced by cimetidine on the peritubular tissue

Copper transporter 1 (CTR1) expression by mouse testicular germ cells, but not Sertoli cells, is essential for functional spermatogenesis.

An imbalance in copper (Cu) tissue homeostasis has a degenerative effect on spermatogenesis and male fertility. The high-affinity Cu transporter 1 (CTR1; SLC31A1) is the major protein responsible for Cu acquisition in eukaryotes and is highly expressed in mouse testes. Studies on yeast and Drosophila have demonstrated the conserved essential function of Cu and CTR1 for meiosis and fertility, implying that CTR1 may play an essential function in mammalian spermatogenesis. In mice, spermatogenesis takes place within the seminiferous epithelium, where tight junctions between somatic Sertoli cells (SCs) create a specialized microenvironment for the development of meiotic germ cells (GCs) by tightly regulating the free transport of metabolites and ions to reach these cells. Here, it is demonstrated that within the seminiferous epithelium, CTR1 is expressed on the membrane of primary pachytene spermatocytes and SCs. To examine the physiological significance of CTR1 in spermatogenesis, mice with a GC-specific (Ctr1ΔGC) and SC-specific (Ctr1ΔSC) disruption of the Ctr1 gene were generated. The testis of Ctr1ΔGC mice exhibits a severe progressive loss of GCs starting at postnatal day (PND) 28 leading to testis hypoplasia by adulthood. No spermatogenic recovery was observed in Ctr1ΔGC testis beyond PND 41, despite the presence of FOXO-1 expressing undifferentiated spermatogonial cells. However, Ctr1ΔSC mice displayed functional spermatogenesis and were fertile, even though testicular Cu levels and Cu-dependent cellular activities were significantly reduced. These results reveal, for the first time, the importance of CTR1 expression by GCs for maintaining functional spermatogenesis