Triplex radiometric, photoacoustic, and ultrasonic imaging based on single-pulse excitation.

In this Letter, we propose a novel triplex-parameter detection method to realize simultaneous radiometric, photoacoustic, and ultrasonic imaging based on single-pulse excitation. The optical attenuation, optical absorption, and acoustic impedance properties can be obtained simultaneously by analyzing the photoacoustic signals and the ultrasonic echo signals. To test the feasibility and accuracy of this method, agar phantoms with different absorption coefficients and elastic coefficients were measured. Then, this method was experimentally verified by imaging a leaf skeleton piece embedded in an agar cylinder. Furthermore, pilot experiments were performed by triplex imaging of pig ear tissue ex vivo to characterize the cartilage and surrounding tissue. Experimental results demonstrated that this technique has future potentials for visualizing and providing the functional and structural information of biological tissues.

Automated Writing Assessments Measure Undergraduate Learning after Completion of a Computer-Based Cellular Respiration Tutorial.

The focus of biology education has shifted from memorization to conceptual understanding of core biological concepts such as matter and energy relationships. To examine undergraduate learning about matter and energy, we incorporated constructed-response (CR) questions into an interactive computer-based tutorial. The objective of this tutorial is to teach students about matter and energy and help dispel common misconceptions through the context of cellular respiration. We used a constructed-response classifier (CRC) tool to categorize ideas in responses to three CR questions and measure changes in student thinking about cellular respiration. Our data set includes 841 undergraduates from 19 geographically diverse institutions including two-year colleges, primarily undergraduate institutions, and research-intensive colleges and universities. We found students from all institution types included more scientific ideas in CRs post-tutorial. Students used an average of 2.1 ideas in CRs and frequently used both scientific and developing ideas. We found this mixed thinking persisted after the tutorial regardless of institution type. Students' multiple-choice (MC) selections were correlated with their CRs, but CRs revealed more mixed thinking than would be inferred from MC responses. Our study shows a CRC tool can measure student learning after a computer-based tutorial and provides more complete information than MC responses.

Introductory biology undergraduate students' mixed ideas about genetic information flow.

The core concept of genetic information flow was identified in recent calls to improve undergraduate biology education. Previous work shows that students have difficulty differentiating between the three processes of the Central Dogma (CD; replication, transcription, and translation). We built upon this work by developing and applying an analytic coding rubric to 1050 student written responses to a three-question item about the CD. Each response was previously coded only for correctness using a holistic rubric. Our rubric captures subtleties of student conceptual understanding of each process that previous work has not yet captured at a large scale. Regardless of holistic correctness scores, student responses included five or six distinct ideas. By analyzing common co-occurring rubric categories in student responses, we found a common pair representing two normative ideas about the molecules produced by each CD process. By applying analytic coding to student responses preinstruction and postinstruction, we found student thinking about the processes involved was most prone to change. The combined strengths of analytic and holistic rubrics allow us to reveal mixed ideas about the CD processes and provide a detailed picture of which conceptual ideas students draw upon when explaining each CD process.

Mixed Student Ideas about Mechanisms of Human Weight Loss.

Recent calls for college biology education reform have identified "pathways and transformations of matter and energy" as a big idea in biology crucial for students to learn. Previous work has been conducted on how college students think about such matter-transforming processes; however, little research has investigated how students connect these ideas. Here, we probe student thinking about matter transformations in the familiar context of human weight loss. Our analysis of 1192 student constructed responses revealed three scientific (which we label "Normative") and five less scientific (which we label "Developing") ideas that students use to explain weight loss. Additionally, students combine these ideas in their responses, with an average number of 2.19 ± 1.07 ideas per response, and 74.4% of responses containing two or more ideas. These results highlight the extent to which students hold multiple (both correct and incorrect) ideas about complex biological processes. We described student responses as conforming to either Scientific, Mixed, or Developing descriptive models, which had an average of 1.9 ± 0.6, 3.1 ± 0.9, and 1.7 ± 0.8 ideas per response, respectively. Such heterogeneous student thinking is characteristic of difficulties in both conceptual change and early expertise development and will require careful instructional intervention for lasting learning gains.

Through the Eyes of Faculty: Using Personas as a Tool for Learner-Centered Professional Development.

College science instructors need continuous professional development (PD) to meet the call to evidence-based practice. New PD efforts need to focus on the nuanced blend of factors that influence instructors' teaching practices. We used persona methodology to describe the diversity among instructors who were participating in a long-term PD initiative. Persona methodology originates from ethnography. It takes data from product users and compiles those data in the form of fictional characters. Personas facilitate user-centered design. We identified four personas among our participants: Emma the Expert views herself as the subject-matter expert in the classroom and values her hard-earned excellence in lecturing. Ray the Relater relates to students and focuses on their points of view about innovative pedagogies. Carmen the Coach coaches her students by setting goals for them and helping them develop skill in scientific practices. Beth the Burdened owns the responsibility for her students' learning and feels overwhelmed that students still struggle despite her use of evidence-based practice. Each persona needs unique PD. We suggest ways that PD facilitators can use our personas as a reflection tool to determine how to approach the learners in their PD. We also suggest further avenues of research on learner-centered PD.

Comparative efficacy of tilmicosin versus tulathromycin as a metaphylactic antimicrobial in feedlot calves at moderate risk for respiratory disease.

The purpose of this study was to compare the efficacy and cost-effectiveness of tilmicosin (MIC) versus tulathromycin (DRAX) as a metaphylactic antimicrobial in feedlot calves at moderate risk for bovine respiratory disease (BRD). Calves that received DRAX had significantly (P < or = .05) lower initial BRD treatment rates compared with calves that received MIC. However, there were no significant differences in the BRD relapse rate, railer rate, total mortality rate, BRD mortality rate, average daily gain, and dry matter conversion between the two groups. The economic advantage of the MIC group was Can$8.29/animal. Based on these results, while DRAX was more efficacious in reducing initial treatments for BRD in feedlot calves at moderate risk for disease, MIC was more cost-effective. The lower initial BRD treatment costs in the DRAX group did not offset the higher metaphylactic cost of DRAX.

A Faculty Professional Development Model That Improves Student Learning, Encourages Active-Learning Instructional Practices, and Works for Faculty at Multiple Institutions.

Helping faculty develop high-quality instruction that positively affects student learning can be complicated by time limitations, a lack of resources, and inexperience using student data to make iterative improvements. We describe a community of 16 faculty from five institutions who overcame these challenges and collaboratively designed, taught, iteratively revised, and published an instructional unit about the potential effect of mutations on DNA replication, transcription, and translation. The unit was taught to more than 2000 students in 18 courses, and student performance improved from preassessment to postassessment in every classroom. This increase occurred even though faculty varied in their instructional practices when they were teaching identical materials. We present information on how this faculty group was organized and facilitated, how members used student data to positively affect learning, and how they increased their use of active-learning instructional practices in the classroom as a result of participation. We also interviewed faculty to learn more about the most useful components of the process. We suggest that this professional development model can be used for geographically separated faculty who are interested in working together on a known conceptual difficulty to improve student learning and explore active-learning instructional practices.

What Motivates Biology Instructors to Engage and Persist in Teaching Professional Development?

We conducted a study of 19 biology instructors participating in small, local groups at six research-intensive universities connected to the Automated Analysis of Constructed Response (AACR) project (www.msu.edu/∼aacr). Our aim was to uncover participants' motivation to persist in a long-term teaching professional development effort, a topic that is understudied in discipline-based educational research. We interviewed each participant twice over a 2-year period and conducted qualitative analyses on the data, using expectancy-value theory as a framework for considering motivation. Our analyses revealed that motivation among instructors was high due to their enjoyment of the AACR groups. The high level of motivation is further explained by the fact that AACR groups facilitated instructor involvement with the larger AACR project. We also found that group dynamics encouraged persistence; instructors thought they might never talk with colleagues about teaching in the absence of AACR groups; and groups were perceived to have a low-enough time requirement to warrant sustained involvement. We conclude that instructors have persisted in AACR groups because the groups provided great value with limited cost. The characterization of instructor experiences described here can contribute to a better understanding of faculty needs in teaching professional development.

Effects of oral administration of tilmicosin on pulmonary inflammation in piglets experimentally infected with Actinobacillus pleuropneumoniae.

OBJECTIVES: To determine the effects of oral administration of tilmicosin in piglets experimentally infected with Actinobacillus pleuropneumoniae. ANIMALS: Forty 3-week-old specific-pathogen free piglets. PROCEDURES: Piglets were assigned to 1 of 4 groups as follows: 1) uninfected sham-treated control piglets; 2) infected untreated piglets that were intratracheally inoculated with 10(7) CFUs of A pleuropneumoniae; 3) infected treated piglets that were intratracheally inoculated with A pleuropneumoniae and received tilmicosin in feed (400 ppm [microg/g]) for 7 days prior to inoculation; or 4) infected treated piglets that were intratracheally inoculated with A pleuropneumoniae and received chlortetracycline (CTC) in feed (1100 ppm [microg/gl) for 7 days prior to inoculation. Bronchoalveolar lavage (BAL) fluid and lung tissue specimens of piglets for each group were evaluated at 3 or 24 hours after inoculation. For each time point, 4 to 6 piglets/group were studied. RESULTS: Feeding of CTC and tilmicosin decreased bacterial load in lungs of infected piglets. Tilmicosin delivered in feed, but not CTC, enhanced apoptosis in porcine BAL fluid leukocytes. This was associated with a decrease in LTB4 concentrations in BAL fluid of tilmicosin-treated piglets, compared with untreated and CTC-treated piglets, and also with a significant decrease in the number of pulmonary lesions. Tilmicosin inhibited infection-induced increases in rectal temperatures, as measured in untreated and CTC-treated piglets. Pulmonary neutrophil infiltration and prostaglandin E2 concentrations in the BAL fluid were not significantly different among groups at any time. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of tilmicosin to infected piglets induces apoptosis in BAL fluid leukocytes and decreases BAL fluid LTB4 concentrations and inflammatory lung lesions.

Examining the impact of question surface features on students' answers to constructed-response questions on photosynthesis.

One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of two question prompts. We asked four versions of the question with different combinations of the two plant species and order of prompts in an introductory cell biology course. We found that there was not a significant difference in the content of student responses to versions of the question stem with different species or order of prompts, using both computerized lexical analysis and expert scoring. We conducted 20 face-to-face interviews with students to further probe the effects of question wording on student responses. During the interviews, we found that students thought that the plant species was neither relevant nor confusing when answering the question. Students identified the prompts as both relevant and confusing. However, this confusion was not specific to a single version.

Liquid chromatography-electrospray tandem mass spectrometric assay suitable for quantitation of halofuginone in plasma.

An LC-MS/MS method was developed to quantitate the potential antitumor agent halofuginone in plasma. The assay uses 0.2 ml of plasma; chlorohalofuginone internal standard; acetonitrile for protein precipitation; a Phenomenex SYNERGI 4 micro Polar RP 80A (4 microm, 100 mm x 2 mm) column; an isocratic mobile phase of methanol:water:formic acid (80:20:0.02, v/v/v); and positive-ion electrospray ionization with selective reaction monitoring detection. Halofuginone eluted at approximately 2.4 min, internal standard eluted at approximately 2.9 min, and no endogenous materials interfered with their measurement. The assay was accurate, precise, and linear between 0.1 and 100 ng/ml. Halofuginone could be quantitated in dog plasma for at least 24 h after an i.v. dose of 0.1mg/kg. The assay is being used in ongoing pharmacokinetic studies of halofuginone.

Agonist-like, replacement pharmacotherapy for stimulant abuse and dependence.

Stimulant abuse and dependence are disproportionately problematic due to the combination of legal and social issues added to the serious behavioural and biological features of the disorders. These problems are compounded by adverse consequences for families and society. Illegality and stigma multiply the consequences of use and difficulties in providing treatment. Specific behavioural interventions have been demonstrated as useful in treatment of substance use disorders (SUDs). Medications also have an important role in treatment. Effective agonist and antagonist pharmacotherapies as well as symptomatic treatments exist for opioid and nicotine dependence. Neither agonists nor antagonists have been approved as uniquely effective for treatment of stimulant abuse or dependence. Still, promising results are emerging for an agonist-like or 'replacement' strategy paralleling that for nicotine and opioid dependence. Supporting data have emerged from both preclinical and clinical research environments. There are scientific, clinical, social, and legal impediments to application of an agonist-like approach to stimulant abuse and dependence. Some resemble past and current concerns about opioid replacement. Others are unique to the stimulant agents, effects, and clinical features. Here, the authors consider (1) agonist and antagonist pharmacotherapy strategies; (2) preclinical research, including methodological approaches, opioid and nicotine replacement, and agonists for stimulant dependence; (3) clinical reports with stimulant medications in cocaine dependence, and the amphetamine replacement strategy for amphetamine dependence; (4) application of agonist-like/replacement strategies, including clinical requirements and risks; and (5) directions for research.

Efficacy of tilmicosin in the control of experimentally induced Actinobacillus pleuropneumoniae infection in swine.

The efficacy of tilmicosin administered in the feed to control Actinobacillus pleuropneumoniae infections in pigs was evaluated through a multisite, multitrial study. For each of 6 trials, 48 pigs (stratified by weight and sex) were randomly assigned to 6 to 8 pens. Medicated feed containing tilmicosin (200 g/t) and unmedicated feed were randomly assigned at the pen level and were provided ad libitum from day -7 to trial termination (day 14). Seeder pigs (inoculated intranasally with A. pleuropneumoniae serotype 1 and showing signs of clinical disease) were introduced to each pen on day 0. Rates of death, gross lesions, and culture of A. pleuropneumoniae at necropsy, clinical scores, average daily gain in weight, and average body temperature were compared between the medicated and unmedicated pigs. Compared with the unmedicated pigs, significantly fewer (P < 0.05) pigs given tilmicosin had lesions typical of A. pleuropneumoniae or had A. pleuropneumoniae isolated from their tissues at necropsy. Together with a significant reduction (P < 0.05) in the average percentage of pneumonic lung involvement (both visually and by weight), there were reductions in the numbers of pigs with moderate and severe pneumonic lung lesions and with A. pleuropneumoniae associated mortality. With tilmicosin treatment, the average daily weight gain, daily temperature, abdominal appearance, attitude, and respiration were also significantly better (P < 0.05). The results of this study demonstrate the in vivo effectiveness of tilmicosin (200 g/t) in controlling pleuropneumonia among swine experimentally infected with A. pleuropneumoniae.

Supplementing introductory biology with on-line curriculum*.

We developed web-based modules addressing fundamental concepts of introductory biology delivered through the LON-CAPA course management system. These modules were designed and used to supplement large, lecture-based introductory biology classes. Incorporating educational principles and the strength of web-based instructional technology, choices were made about knowledge presentation, representation, and construction (W. A. Nelson, D. B. Palumbo (1992) J. Educ. Media Hypermedia 1, 287-299). Knowledge presentation focused on big and connecting ideas. Knowledge representation provided students the opportunity to interact with concepts in several ways using multiple representations. For knowledge construction, we facilitated students' active and meaningful interactions with content using interwoven high-level questions. Students' extended responses to a questionnaire indicated that these modules influenced the students learning in meaningful ways. (For access to demonstration modules, go to demo.lon-capa.org/cgi-bin/signon.pl?hhmi.).

Mesoscale convective system surface pressure anomalies responsible for meteotsunamis along the U.S. East Coast on June 13th, 2013.

Two destructive high-frequency sea level oscillation events occurred on June 13th, 2013 along the U.S. East Coast. Seafloor processes can be dismissed as the sources, as no concurrent offshore earthquakes or landslides were detected. Here, we present evidence that these tsunami-like events were generated by atmospheric mesoscale convective systems (MCSs) propagating from inland to offshore. The USArray Transportable Array inland and NOAA tide gauges along the coast recorded the pressure anomalies associated with the MCSs. Once offshore, the pressure anomalies generated shallow water waves, which were amplified by the resonance between the water column and atmospheric forcing. Analysis of the tidal data reveals that these waves reflected off the continental shelf break and reached the coast, where bathymetry and coastal geometry contributed to their hazard potential. This study demonstrates that monitoring MCS pressure anomalies in the interior of the U.S. provides important observations for early warnings of MCS-generated tsunamis.

What are they thinking? Automated analysis of student writing about acid-base chemistry in introductory biology.

Students' writing can provide better insight into their thinking than can multiple-choice questions. However, resource constraints often prevent faculty from using writing assessments in large undergraduate science courses. We investigated the use of computer software to analyze student writing and to uncover student ideas about chemistry in an introductory biology course. Students were asked to predict acid-base behavior of biological functional groups and to explain their answers. Student explanations were rated by two independent raters. Responses were also analyzed using SPSS Text Analysis for Surveys and a custom library of science-related terms and lexical categories relevant to the assessment item. These analyses revealed conceptual connections made by students, student difficulties explaining these topics, and the heterogeneity of student ideas. We validated the lexical analysis by correlating student interviews with the lexical analysis. We used discriminant analysis to create classification functions that identified seven key lexical categories that predict expert scoring (interrater reliability with experts = 0.899). This study suggests that computerized lexical analysis may be useful for automatically categorizing large numbers of student open-ended responses. Lexical analysis provides instructors unique insights into student thinking and a whole-class perspective that are difficult to obtain from multiple-choice questions or reading individual responses.

Iron deficiency causes a shift in AMP-activated protein kinase (AMPK) subunit composition in rat skeletal muscle.

BACKGROUND: As a cellular energy sensor, the 5'AMP-activated protein kinase (AMPK) is activated in response to energy stresses such as hypoxia and muscle contraction. To determine effects of iron deficiency on AMPK activation and signaling, as well as the AMPK subunit composition in skeletal muscle, rats were fed a control (C=50-58 mg/kg Fe) or iron deficient (ID=2-6 mg/kg Fe) diet for 6-8 wks. RESULTS: Their respective hematocrits were 47.5% ± 1.0 and 16.5% ± 0.6. Iron deficiency resulted in 28.3% greater muscle fatigue (p<0.01) in response to 10 min of stimulation (1 twitch/sec) and was associated with a greater reduction in phosphocreatine (C: Resting 24.1 ± 0.9 µmol/g, Stim 13.1 ± 1.5 µmol/g; ID: Resting 22.7 ± 1.0 µmol/g, Stim 3.2 ± 0.7 µmol/g; p<0.01) and ATP levels (C: Resting 5.89 ± 0.48 µmol/g, Stim 6.03 ± 0.35 µmol/g; ID: Resting 5.51 ± 0.20 µmol/g, Stim 4.19 ± 0.47 µmol/g; p<0.05). AMPK activation increased with stimulation in muscles of C and ID animals. A reduction in Cytochrome c and other iron-dependent mitochondrial proteins was observed in ID animals (p<0.01). The AMPK catalytic subunit (α) was examined because both isoforms are known to play different roles in responding to energy challenges. In ID animals, AMPKα2 subunit protein content was reduced to 71.6% of C (p<0.05), however this did not result in a significant difference in resting AMPKα2 activity. AMPKα1 protein was unchanged, however an overall increase in AMPKα1 activity was observed (C: 0.91 pmol/mg/min; ID: 1.63 pmol/mg/min; p<0.05). Resting phospho Acetyl CoA Carboxylase (pACC) was unchanged. In addition, we observed significant reductions in the ß2 and γ3 subunits of AMPK in response to iron deficiency. CONCLUSIONS: This study indicates that chronic iron deficiency causes a shift in the expression of AMPKα, ß, and γ subunit composition. Iron deficiency also causes chronic activation of AMPK as well as an increase in AMPKα1 activity in exercised skeletal muscle.

Exploring undergraduates' understanding of photosynthesis using diagnostic question clusters.

We present a diagnostic question cluster (DQC) that assesses undergraduates' thinking about photosynthesis. This assessment tool is not designed to identify individual misconceptions. Rather, it is focused on students' abilities to apply basic concepts about photosynthesis by reasoning with a coordinated set of practices based on a few scientific principles: conservation of matter, conservation of energy, and the hierarchical nature of biological systems. Data on students' responses to the cluster items and uses of some of the questions in multiple-choice, multiple-true/false, and essay formats are compared. A cross-over study indicates that the multiple-true/false format shows promise as a machine-gradable format that identifies students who have a mixture of accurate and inaccurate ideas. In addition, interviews with students about their choices on three multiple-choice questions reveal the fragility of students' understanding. Collectively, the data show that many undergraduates lack both a basic understanding of the role of photosynthesis in plant metabolism and the ability to reason with scientific principles when learning new content. Implications for instruction are discussed.