Identifying, attributing, and dispelling student misconceptions in electrochemistry

This dissertation contains six chapters. The first chapter is a review of the chemical education literature concerning suggestions or personal opinions promoting one pedagogical method of teaching oxidation-reduction reactions or electrochemistry, descriptions of real world examples of oxidation-reduction reactions or electrochemistry, and empirical data aimed at identifying student difficulties or misconceptions related to oxidation-reduction reactions or electrochemistry. The second through fifth chapters contain the results of my research on student misconceptions in electrochemistry as they were submitted for journal publication. The sixth chapter contains an opinion paper concerning the possible mismatch between Science-Technology-Society/ChemCom-based high school chemistry courses and traditional introductory college-level chemistry courses. This article originated as a preliminary examination question concerning the advantages and disadvantages of the STS movement in science education;The first study is a replication, with additions, of a clinical interview study performed by Garnett and Treagust (J. Res. Sci. Teach., 1992, 29, 1079-1099). We were able to confirm most of the misconceptions reported by these authors and reported several new misconceptions;The second study focused on the student misconceptions regarding current flow in electrolyte solutions and the salt bridge reported in the first study. This study briefly discussed student misconceptions, identified chemistry textbooks as possible sources of these misconceptions, and discussed the use of computer animations and a confrontational teaching method as an effective method of preventing or dispelling these misconceptions;The third study investigated introductory college-level chemistry textbooks as a source of student misconceptions in electrochemistry. The oxidation-reduction and electrochemistry chapters of ten chemistry textbooks were analyzed for vague or misleading statements and illustrations that could lead to student misconceptions. Several suggestions for textbooks authors were also reported;The fourth study investigated the effects of computer animations depicting chemical processes on the molecular level and chemical demonstration-based conceptual change instruction on student responses to conceptual questions based on the misconception that electron migration constitutes current flow in electrolyte solutions. Computer animations had little effect on student conceptions, but conceptual change instruction significantly decreased the proportion of student responses consistent with the misconception

Development and application of a self-referencing glucose microsensor for the measurement of glucose consumption by pancreatic ?-cells

Glucose gradients generated by an artificial source and ?-cells were measured using an enzyme-based glucose microsensor, 8-?m tip diameter, as a self-referencing electrode. The technique is based on a difference measurement between two locations in a gradient and thus allows us to obtain real-time flux values with minimal impact of sensor drift or noise. Flux values were derived by incorporation of the measured differential current into Fick's first equation. In an artificial glucose gradient, a flux detection limit of 8.2 ± 0.4 pmol·cm-2·s-1 (mean ± SEM, n = 7) with a sensor sensitivity of 7.0 ± 0.4 pA/mM (mean ± SEM, n = 16) was demonstrated. Under biological conditions, the glucose sensor showed no oxygen dependence with 5 mM glucose in the bulk medium. The addition of catalase to the bulk medium was shown to ameliorate surface-dependent flux distortion close to specimens, suggesting an underlying local accumulation of hydrogen peroxide. Glucose flux from ?-cell clusters, measured in the presence of 5 mM glucose, was 61.7 ± 9.5 fmol·nL-1·s-1 (mean ± SEM, n = 9) and could be pharmacologically modulated. Glucose consumption in response to FCCP (1 ?M) transiently increased, subsequently decreasing to below basal by 93 ± 16 and 56 ± 6%, respectively (mean ± SEM, n = 5). Consumption was decreased after the application of 10 ?M rotenone by 74 ± 5% (mean ± SEM, n = 4). These results demonstrate that an enzyme-based amperometric microsensor can be applied in the self-referencing mode. Further, in obtaining glucose flux measurements from small clusters of cells, these are the first recordings of the real-time dynamic of glucose movements in a biological microenvironment. <br/

Improving Writing Quality of Capstone Reports

Abstract-Contributions: The main contribution is to share a series of practical methods that improve the writing quality of capstone reports. Background: The ability to write well is critical to the success of an engineering technology graduate. However, the evidence points to the fact that industries are disappointed with the quality of writing skills graduates demonstrate. Intended Outcomes: A faculty review of capstone reports showed little improvement in writing quality from the first course to the second in a two-semester capstone sequence. Therefore, the instructors explored what actions were needed to improve the writing quality of the capstone reports. Application Design: Several changes in the capstone courses were developed and implemented. The changes included 1) using instructional technology as a scaffolding to help frame the writing required for the course and 2) engaging students in iterative writing with feedback. Findings: The assessment data showed a significant improvement, at the 5% level. The iterative process of writing and rewriting the report, coupled with frequent meetings with faculty mentors, proved to be a powerful combination for improving the writing prowess of the students

Lysine Effect on Ruthenium Red and Alcian Blue Preservation and Staining of the Staphylococcal Glycocalyx

The effect of lysine on ruthenium red (RR) and alcian blue (AB) preservation arid/or staining for transmission electron microscopy of glycocalyces was evaluated for three species of the gram-positive, coagulase-negative staphylococci. A RR and an AB procedure were compared with and without lysine included in the glutaraldehyde prefixation. Minimal or no glycocalyx was preserved or stained by glutaraldehyde fixation only. For all species, the inclusion of lysine increased visualization of fibrous material. RR treatment without lysine, results in sparse or limited fibrous material or artifactual condensations which contrasts with enhanced fibrous material seen when lysine is included with RR. The effect of lysine is also to enhance the visualization of staphylococcal glycocalyx by AB. Without lysine, condensed curved structures are consistently seen following AB processing. In contrast, extensive and elaborate glycocalyces are observed with inclusion of lysine with AB. Thus, ultrastructural visualization by RR and AB of the staphylococcal glycocalyx in the species studied was enhanced by use of lysine

Sequoyah v. TVA, USDC Northern District of TN, Docket No. 3-79-418: TVA’s Brief in Support of Its Motion to Dismiss, or, for Summary Judgment, and in Opposition to Plaintiffs’’ Motion for restraining Order or Preliminary Injunction

Brief prepared by the Tennessee Valley Authority (TVA) in the suit brought by Native American groups seeking an injunction on the Tellico Project. The brief is followed by extensive appendices, including sections of TVA annual reports, and affidavits by John E. Linn, Title Attorney, Tennessee Valley Authority, Ross O. Swimmer, Principal Chief of the Cherokee Nation, and Edward H. Lessne, Director of the Division of Water Resources in the Office of Natural Resources of the Tennessee Valley Authority

Effects of neo-adjuvant chemotherapy for oesophago-gastric cancer on neuro-muscular gastric function

Delayed gastric emptying symptoms are often reported after chemotherapy. This study aims to characterise the effects of chemotherapy on gastric neuro-muscular function. Patients undergoing elective surgery for oesophago-gastric cancer were recruited. Acetylcholinesterase, nNOS, ghrelin receptor and motilin expressions were studied in gastric sections from patients receiving no chemotherapy (n = 3) or oesophageal (n = 2) or gastric (n = 2) chemotherapy. A scoring system quantified staining intensity (0–3; no staining to strong). Stomach sections were separately suspended in tissue baths for electrical field stimulation (EFS) and exposure to erythromycin or carbachol; three patients had no chemotherapy; four completed cisplatin-based chemotherapy within 6 weeks prior to surgery. AChE expression was markedly decreased after chemotherapy (scores 2.3 ± 0.7, 0.5 ± 0.2 and 0 ± 0 in non-chemotherapy, oesophageal- and gastric-chemotherapy groups (p < 0.03 each) respectively. Ghrelin receptor and motilin expression tended to increase (ghrelin: 0.7 ± 0.4 vs 2.0 ± 0.4 and 1.2 ± 0.2 respectively; p = 0.04 and p = 0.2; motilin: 0.7 ± 0.5 vs 2.2 ± 0.5 and 2.0 ± 0.7; p = 0.06 and p = 0.16). Maximal contraction to carbachol was 3.7 ± 0.7 g and 1.9 ± 0.8 g (longitudinal muscle) and 3.4 ± 0.4 g and 1.6 ± 0.6 (circular) in non-chemotherapy and chemotherapy tissues respectively (p < 0.05 each). There were loss of AChE and reduction in contractility to carbachol. The tendency for ghrelin receptors to increase suggests an attempt to upregulate compensating systems. Our study offers a mechanism by which chemotherapy markedly alters neuro-muscular gastric function

Improved Animal Model for Vibration Injury Study

Hand-Arm Vibration Syndrome is a debilitating condition that affects millions of power-tool users in the  U.S. Research into its etiology has been hampered by deficiencies in animal models used for vibration studies.  Our objective was to design an animal vibration injury model that: 1) vibrates only the studied limb, not  the body; and 2) avoids anaesthesia, thus allowing purer focus on physiological effects of vibration while  reducing pain and distress for the animals, thereby enhancing their well-being. We compared advantages  and disadvantages of several models, studying body temperature, body weight, tissue perfusion, vascular  pathohistology, and general animal condition. Our model uses an apparatus that limits vibration to one  body part and a specially designed cage that minimizes animal stress and suffering, eliminating the need for  anaesthesia. It is ideal for the study of vibration injury, providing tissue damaged purely by vibration that  can be used for pathohistology and biochemical study.

Functional and anatomical deficits in visceral nociception with age: a mechanism of silent appendicitis in the elderly?

The ability to sense visceral pain during appendicitis is diminished with age leading to delay in seeking health care and poorer clinical outcomes. To understand the mechanistic basis of this phenomenon, we examined visceral nociception in aged mouse and human tissue. Inflamed and noninflamed appendixes were collected from consenting patients undergoing surgery for the treatment of appendicitis or bowel cancer. Supernatants were generated by incubating samples in buffer and used to stimulate multiunit activity in intestinal preparations, or single-unit activity from teased fibres in colonic preparations, of young and old mice. Changes in afferent innervation with age were determined by measuring the density of calcitonin gene-related peptide-positive afferent fibres and by counting dorsal root ganglia back-labelled by injection of tracer dye into the wall of the colon. Finally, the effect of age on nociceptor function was studied in mouse and human colon. Afferent responses to appendicitis supernatants were greatly impaired in old mice. Further investigation revealed this was due to a marked reduction in the afferent innervation of the bowel and a substantial impairment in the ability of the remaining afferent fibres to transduce noxious stimuli. Translational studies in human tissue demonstrated a significant reduction in the multiunit but not the single-unit colonic mesenteric nerve response to capsaicin with age, indicative of a loss of nociceptor innervation. Our data demonstrate that anatomical and functional deficits in nociception occur with age, underpinning the atypical or silent presentation of appendicitis in the elderly

Ex vivo study of human visceral nociceptors.

OBJECTIVE: The development of effective visceral analgesics free of deleterious gut-specific side effects is a priority. We aimed to develop a reproducible methodology to study visceral nociception in human tissue that could aid future target identification and drug evaluation. DESIGN: Electrophysiological (single unit) responses of visceral afferents to mechanical (von Frey hair (VFH) and stretch) and chemical (bradykinin and ATP) stimuli were examined. Thus, serosal afferents (putative nociceptors) were used to investigate the effect of tegaserod, and transient receptor potential channel, vanilloid 4 (TRPV4) modulation on mechanical responses. RESULTS: Two distinct afferent fibre populations, serosal (n=23) and muscular (n=21), were distinguished based on their differences in sensitivity to VFH probing and tissue stretch. Serosal units displayed sensitivity to key algesic mediators, bradykinin (6/14 units tested) and ATP (4/10), consistent with a role as polymodal nociceptors, while muscular afferents are largely insensitive to bradykinin (0/11) and ATP (1/10). Serosal nociceptor mechanosensitivity was attenuated by tegaserod (-20.8±6.9%, n=6, p<0.05), a treatment for IBS, or application of HC067047 (-34.9±10.0%, n=7, p<0.05), a TRPV4 antagonist, highlighting the utility of the preparation to examine the mechanistic action of existing drugs or novel analgesics. Repeated application of bradykinin or ATP produced consistent afferent responses following desensitisation to the first application, demonstrating their utility as test stimuli to evaluate analgesic activity. CONCLUSIONS: Functionally distinct subpopulations of human visceral afferents can be demonstrated and could provide a platform technology to further study nociception in human tissue