Digital Commons Network^™

Special Issue: Microbial Community Modeling: Prediction Of Microbial Interactions And Community Dynamics, Hyun-Seob Song

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Microbial communities are networks of species, the interaction structure of which dynamically reorganizes in a varying environment. Even in a static condition, community dynamics are often difficult to predict due to highly nonlinear interspecies interactions. Understanding the fundamental principles of microbial interactions is therefore key for predicting and harnessing community function and properties. As extensively reviewed previously, mathematical models and computational methods that can predictively link interactions to community behaviors are indispensable tools for achieving this goal [1].

Impacts Of Cover Crops On Soil Physical Properties: Field Capacity, Permanent Wilting Point, Soil-Water Holding Capacity, Bulk Density, Hydraulic Conductivity, And Infiltration, Suat Irmak, Vivek Sharma, Ali T. Mohammed, Koffi Djaman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Field experiments were carried out to quantify the effects of cover cropping on soil physical properties. Field capacity (FC), permanent wilting point (PWP), soil-water holding capacity (SWHC), bulk density (  b), saturated and unsaturated hydraulic conductivity (Ks and Kus, respectively), and infiltration rates were measured and compared for four land cover treatments [cover crop without seed maize (CC), seed maize followed by cover crop (SCCC), bare soil, and seed maize without cover crop (SC)] in three large-scale production fields (~64 ha each) with silt loam soil in the 2012-2013, 2013-2014, 2014-2015, and 2015-2016 cover crop growing seasons. All production …

Synthesis, Secretion, And Perception Of Abscisic Acid Regulates Stress Responses In Chlorella Sorokiniana, Maya Khasin, Rebecca E. Cahoon, Sophie Alvarez, Richard Beckeris, Seong-Il Eyun, Qidong Jia, Jean-Jack Riethoven, Kenneth Nickerson, Wayne R. Riekhof

Kenneth Nickerson Papers

Abscisic acid (ABA) is a phytohormone that has been extensively characterized in higher plants for its roles in seed and bud dormancy, leaf abscission, and stress responses. Genomic studies have identified orthologs for ABA-related genes throughout the Viridiplantae, including in unicellular algae; however, the role of ABA in algal physiology has not been characterized, and the existence of such a role has been a matter of dispute. In this study, we demonstrate that ABA is involved in regulating algal stress responses. Chlorella sorokiniana strain UTEX 1230 contains genes orthologous to those of higher plants which are essential for ABA …

Temporal Variation In Predation Risk May Explain Daily Rhythms Of Foraging Behavior In An Orb-Weaving Spider, J. Colton Watts, Thomas C. Jones, Ashley Herrig, Madeleine Miller, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Daily rhythms occur in numerous physiological and behavioral processes across an immense diversity of taxa, but there remain few cases in which mechanistic links between rhythms of trait expression and organismal fitness have been established. We construct a dynamic optimization model to determine whether risk allocation provides an adaptive explanation for the daily foraging rhythm observed in many species using the orb-weaving spider Cyclosa turbinata as a case study. Our model predicts that female C. turbinata should generally start foraging at lower levels of energy reserves (i.e., should be less bold) during midday when predators are most abundant. We also …

Presence Of Fruits Decreases Probability Of Retaining Flowers In A Sequentially Flowering Plant, Shivani Jadeja, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Both intrinsic and extrinsic plant processes affect the fate of flowers along an inflorescence in sequentially flowering plants. We investigated whether the intrinsic process of competition for limited resource between fruits and flowers owing to resource preemption or sink strength of basal fruits, or architectural effects due to posi- tional differences in the probability of retaining flowers, explains a lower probability of retaining distal flowers inYucca glauca. Further, we investigated how the extrinsic process of seed herbivory interacts with the plant’s intrinsic processes of flower retention. We carried out a field experiment to compare flower retention among nine combi- nations …

Focused Electron-Beam-Induced Deposition For Fabrication Of Highly Durable And Sensitive Metallic Afm-Ir Probes, Wen Qian, Shuo Sun, Jingfeng Song, Charles Nguyen, Stephen Ducharme, Joesph A. Turner

Stephen Ducharme Publications

We report on the fabrication of metallic, ultra-sharp atomic force microscope tips for localized nanoscale infrared (IR) spectrum measurements by using focused electron-beam-induced deposition of platinum or tungsten. The tip length can be controlled by changing the duration time of the electron beam. Probes of 12.0 ± 5.0 nm radius-of-curvature can be routinely produced with high repeatability and near-100% yield. The near-field-enhancement appears stronger at the extremity of the metallic tip, compared with commercial pristine silicon-nitride probe tip. Finally, the performance of the modified metallic tips is demonstrated by imaging PVDF and PMMA thin films, which shows that spatial resolution …

Real Potential, Jennifer Mckitrick

Department of Philosophy: Faculty Publications

There's a student in my philosophy class who has "real potential." I might express this thought in any of the following ways: "She is potentially a philosopher"; "She is a potential philosopher"; "She has the potential to be a philosopher." The first way uses a cognate of "potential" as an adverb to modify "is." The second ways uses "potential" as an adjective to modify "philosopher." However, the third way uses "potential" as a noun to refer to something that the student has. What kind of thing is this potential? One worry about even asking this question is that this nominalization …

Feminist Metaphysics: Can This Marriage Be Saved?, Jennifer Mckitrick

Department of Philosophy: Faculty Publications

Feminist metaphysics is simultaneously feminist theorizing and metaphysics. Part of feminist metaphysics concerns social ontology and considers such questions as, What is the nature of social kinds, such as genders? Feminist metaphysicians also consider whether gendered perspectives influence metaphysical theorizing; for example, have approaches to the nature of the self or free will been conducted from a masculinist perspective, and would a feminist perspective yield different theories? Some feminist metaphysicians develop metaphysical theories with the aim of furthering certain social goals, such as gender equality.

Despite these and other intriguing research projects, feminist metaphysics faces challenges from two flanks: one …

Neonchocotyle Violantei N. Sp. (Monogenea, Hexabothriidae) From Pseudobatos Lentiginosus (Rhinopristiformes, Rhinobatidae) Of Yucatán, Gulf Of Mexico = Neonchocotyle Violantei N. Sp. (Monogenea, Hexabothriidae) Do Pseudobatos Lentiginosus (Rhinopristiformes, Rhinobatidae) De Yucatán, Golfo Do México, Guadalupe Quiterio-Rendon, Scott Monks, Griselda Pulido-Flores

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Abstract

Neonchocotyle violantei n. sp. (Monogenea: Hexabothriidae) infects the gill of the Atlantic guitarfish, Pseudobatos lentiginosus (Rhinopristiformes, Rhinobatidae) from littoral waters of Celestún, Yucatán, Mexico. It is assigned to Neonchocotyle because it has, among other features, an asymmetrical haptor, a seminal receptacle, a smooth oötype, and an egg with two elongate filaments. It differs from Neonchocotyle pastinacae, the only congener, by having a small body (821 long by 315 wide, length to width = 2.6:1), two pairs of microhooks between the haptoral appendix suckers, extracaecal (submarginal) vaginal pores, and 5-9 testes. This is the first record of a species …

A New Species Of Acanthobothrium (Eucestoda: Onchobothriidae) In Aetobatus Cf. Narinari (Myliobatidae) From Campeche, México = Uma Nova Espécie De Acanthobothrium (Eucestoda: Onchobothriidae) Em Aetobatus Cf. Narinari (Myliobatidae) De Campeche, México, Erick Rodríguez-Ibarra, Griselda Pulido-Flores, Juan Violante-González, Scott Monks

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Abstract

The helminthological examination of nine individuals of Aetobatus cf. narinari (spotted eagle ray; raya pinta; arraia pintada) revealed the presence of an undescribed species of cestode of the genus Acanthobothrium. The stingrays were collected from four locations in México: Laguna Términos, south of Isla del Carmen and the marine waters north of Isla del Carmen and Champotón, in the State of Campeche, and Isla Holbox, State of Quintana Roo. The new species, nominated Acanthobothrium marquesi, is a category 3 species (i.e, the strobila is long, has more than 50 proglottids, the numerous testicles greater than 80, and has …

Diversity And Phylogenetic Relationships Of European Species Of Crepidostomum Braun, 1900 (Trematoda: Allocreadiidae) Based On Rdna, With Special Reference To Crepidostomum Oschmarini Zhokhov & Pugacheva, 1998, Romualda Petkevičiūtė, Virmantas Stunžėnas, Alexander E. Zhokhov, Larisa G. Poddubnaya, Gražina Stanevičiūtė

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Background

Within the genus Crepidostomum Braun, 1900, identification of species and taxonomic decisions made only on the basis of adult morphology have resulted in great problems associated with evaluating actual diversity and validity of species. Life cycle data, while equal in importance to adult characters, are scarce, controversial or incomplete for most Crepidostomum spp. In this study, rDNA sequences generated from adult and larval Crepidostomum spp. and some other allocreadiid species were analyzed to reveal the diversity and phylogenetic relationships of the species and their host range. Detailed morphological description based on light microscopy, SEM tegumental surface topography and genetic …

Using Watershed Boundaries To Map Adverse Health Outcomes: Examples From Nebraska, Usa, Brittany Corley, Shannon L. Bartelt-Hunt, Eleanor Rogan, Donald Coulter, John Sparks, Lorena Baccaglini, Madeline Howell, Sidra Liaquat, Rex Commack, Alan S. Kolok

Department of Civil and Environmental Engineering: Faculty Publications

In 2009, a paper was published suggesting that watersheds provide a geospatial platform for establishing linkages between aquatic contaminants, the health of the environment, and human health. This article is a follow-up to that original article. From an environmental perspective, watersheds segregate landscapes into geospatial units that may be relevant to human health outcomes. From an epidemiologic perspective, the watershed concept places anthropogenic health data into a geospatial framework that has environmental relevance. Research discussed in this article includes information gathered from the literature, as well as recent data collected and analyzed by this research group. It is our contention …

Sustainable Waste-To-Energy Technologies: Bioelectrochemical Systems, Rami Ziara, Bruce Dvorak, Jeyamkondan Subbiah

Department of Civil and Environmental Engineering: Faculty Publications

The food industry produces a large amount of waste and wastewater, of which most of the constituents are carbohydrates, proteins, lipids, and organic fibers. Therefore food wastes are highly biodegradable and energy rich. Bioelectrochemical systems (BESs) are systems that use microorganisms to biochemically catalyze complex substrates into useful energy products, in which the catalytic reactions take place on electrodes. Microbial fuel cells (MFCs) are a type of bioelectrochemical systems that oxidize substrates and generate electric current. Microbial electrolysis cells (MECs) are another type of bioelectrochemical systems that use an external power source to catalyze the substrate into by-products such as …

Three-Dimensional Modeling Of Nitrate-N Transport In Vadose Zone: Roles Of Soil Heterogeneity And Groundwater Flux, Simin Akbariyeh, Shannon L. Bartelt-Hunt, Daniel D. Snow, Xu Li, Zhenghong Tang, Yusong Li

Department of Civil and Environmental Engineering: Faculty Publications

Contamination of groundwater from nitrogen fertilizers in agricultural lands is an important environmental and water quality management issue. It is well recognized that in agriculturally intensive areas, fertilizers and pesticides may leach through the vadose zone and eventually reach groundwater. While numerical models are commonly used to simulate fate and transport of agricultural contaminants, few models have considered a controlled field work to investigate the influence of soil heterogeneity and groundwater flow on nitrate-N distribution in both root zone and deep vadose zone.

In this work, a numerical model was developed to simulate nitrate-N transport and transformation beneath a center …

Comparative Study On The Performance Of Anaerobic And Aerobic Biotrickling Filter For Removal Of Chloroform, Bineyam Mezgebe, Keerthisaranya Palanisamy, George A. Sorial, Endalkachew Sahle-Demessie, Ashraf Aly Hassan, Jingrang Lu

Department of Civil and Environmental Engineering: Faculty Publications

Use of biotrickling filter (BTF) for gas phase treatment of volatile trihalomethanes (THMs) stripped from water treatment plants could be an attractive treatment option. The aim of this study is to use laboratory-scale anaerobic BTF to treat gaseous chloroform (recalcitrant to biological transformation) as a model THM and compare results with aerobic BTF. Additional investigations were conducted to determine the microbial diversity present within the BTFs. Chloroform is a hydrophobic volatile THM known to be difficult to biodegrade. To improve the degradation process, ethanol was used as a cometabolite at a different ratio to chloroform. The experimental plan was designed …

In Vitro Digestion And Characterization Of 2s Albumin And Digestion-Resistant Peptides In Pecan, Jelena Spiric, Stef J. Koppelman, Andre Knulst, Julie A. Nordlee, Steve L. Taylor, Joseph L. Baumert

Department of Food Science and Technology: Faculty Publications

The 2S albumins are one of the major protein families involved in severe food allergic reactions to nuts, seeds, and legumes, thus potentially making these proteins clinically relevant for allergic sensitization and potential diagnostic markers. In this study, we sought to purify native 2S albumin protein from pecan to further characterize this putative allergen. The purified 2S albumin, Car i 1, from pecan was found to be resistant to digestion by pepsin in simulated gastric fluid (SGF) and comparatively stable to proteolysis by trypsin and pancreatin in simulated intestinal fluid (SIF). Digestion of purified Car i 1 in SGF and …

Fabrication Of Mnox/Mwcnts-Gc Nanocatalyst For Oxygen Evolution Reaction, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Amr M. Arafa Eng.

Chemical Engineering

Manganese oxide (MnOx) and multiwalled carbon nanotubes (MWCNTs) are intended to modify the GC electrode for oxygen evolution reaction (OER). Optimization of MnOx loading is carried out and the deposition of 55 cycles was sufficient to obtain the highest activity toward OER. The stability of the catalyst is enhanced by the addition of MWCNTs. As a result, an amount of 22 kWh/Kg of O2 of energy is saved. Several techniques including cyclic voltammetry, linear sweep voltammetry, chronoamperometry, chronopotentiometry, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy will be combined to track the catalyst activity and to determine its morphology …

Vulnerability Of Grazing And Confined Livestock In The Northern Great Plains To Projected Mid- And Late-Twenty-First Century Climate, Justin D. Derner, David Briske, Matt Reeves, T. M. Brown-Brandl, Miranda Meehan, Dana M. Blumenthal, William E. Riebsame

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The Northern Great Plains (NGP) region of the USA—which comprises Montana, Wyoming, Colorado, North Dakota, South Dakota, and Nebraska—is a largely rural area that provides numerous ecosystem services, including livestock products, cultural services, and conservation of biological diversity. The region contains 25% of the Nation’s beef cattle and approximately one-third of the confined beef cattle, as well as the largest remaining native prairie in the US—the Northern Mixedgrass Prairie. With rising atmospheric CO2, the NGP is projected to experience warmer and longer growing seasons, greater climatic variability, and more extreme events (e.g., increased occurrence of large precipitation events). These climatic …

The National Wildlife Strike Database: A Scientific Foundation To Enhance Aviation Safety, Richard A. Dolbeer, Michael J. Begier, John R. Weller

United States Department of Agriculture Wildlife Services: Staff Publications

The U.S. Federal Aviation Administration's (FAA) National Wildlife Strike Database (NWSD) documents reports of civil aircraft collisions with wildlife in USA. The NWSD has been managed by the Wildlife Services Program of the U.S. Department of Agriculture through an interagency agreement since its inception. Although the NWSD includes about 170,000 reports of civil aircraft collisions with wildlife (97% birds) from 1990-2015 (14,000 in 2015), the overriding focus has been the quality control of data entered for over 90 variables ranging from species and numbers of wildlife struck, location and time of day, phase and height of flight, aircraft type, components …

To Live And Fly In La: Using Bird Strike And Management Program Information To Improve Safety At Airports In The Los Angeles Basin, Todd J. Pitlik, Elizabeth Hermann, Eric Peralta, Brian E. Washburn

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife-aircraft collisions (wildlife strikes) pose a serious safety risk to aircraft. Wildlife strikes can be evaluated at different levels, include efforts to examine these problems at the national, regional, or state level, or for an individual airport. Similarly, wildlife strikes involving individual wildlife species or guilds can be examined at varying scales. Although wildlife strike analyses at the national, regional, or species/guild level are valuable, airport-specific analyses are essential for the effective implementation and evaluation of integrated wildlife damage management programs as these actions are conducted at the airport level. The species that present hazards to safe aircraft operations varies …

Patterns And Drivers Of Recent Disturbances Across The Temperate Forest Biome, Andreas Sommerfeld, Cornelius Senf, Brian Buma, Anthony W. D’Amato, Tiphaine Després, Ignacio Díaz-Hormazábal, Shawn Fraver, Lee E. Frelich, Álvaro G. Gutiérrez, Sarah J. Hart, Brian J. Harvey, Hong S. He, Tomáš Hlásny, Andrés Holz, Thomas Kitzberger, Dominik Kulakowski, David Lindenmayer, Akira S. Mori, Jörg Müller, Juan Paritsis, George L.W. Perry, Scott L. Stephens, Miroslav Svoboda, Monica G. Turner, Thomas T. Veblen, Rupert Seidl

Geography

Increasing evidence indicates that forest disturbances are changing in response to global change, yet local variability in disturbance remains high. We quantified this considerable variability and analyzed whether recent disturbance episodes around the globe were consistently driven by climate, and if human influence modulates patterns of forest disturbance. We combined remote sensing data on recent (2001–2014) disturbances with in-depth local information for 50 protected landscapes and their surroundings across the temperate biome. Disturbance patterns are highly variable, and shaped by variation in disturbance agents and traits of prevailing tree species. However, high disturbance activity is consistently linked to warmer and …

Beauty Is In The Eye Of The Beer Holder: An Initial Investigation Of The Effects Of Alcohol, Attractiveness, Warmth, And Competence On The Objectifying Gaze In Men, Abigail R. Riemer, Michelle Haikalis, Molly R. Franz, Michael Dodd, David Dilillo, Sarah Gervais

Department of Psychology: Faculty Publications

Despite literature revealing the adverse consequences of objectifying gazes for women, little work has empirically examined origins of objectifying gazes by perceivers. Integrating alcohol myopia and objectification theories, we examined the effects of alcohol as well as perceived female attractiveness, warmth, and competence on objectifying gazes. Specifically, male undergraduates (n = 49) from a large U.S. Midwestern university were administered either an alcoholic or placebo beverage. After consumption, participants were asked to focus on the appearance or personality (counterbalanced) of pictured women who were previously rated as high, average, or low in attractiveness, warmth, and competence. Replicating previous work, appearance …

A Behavioral Mechanistic Investigation Of The Role Of 5-Ht1a Receptors In The Mediation Of Rat Maternal Behavior, Xiaonan Li, Xiaojing Ding, Ruiyong Wu, Leilei Chen, Jun Gao, Gang Hu, Ming Li

Department of Psychology: Faculty Publications

Previous work suggests that 5-HT_1A receptors play a special role in rodent maternal aggression, but not in other aspects of maternal care (e.g. pup retrieval and nest building). The present study re-assessed the basic effects of 5-HT_1A activation or blockade on various maternal responses in postpartum female rats. We also examined the possible behavioral mechanisms underlying the maternal effects of 5-HT_1A. Sprague–Dawley mother rats were injected with a 5-HT_1A agonist 8-OH-DPAT (0.1, 0.5 or 1.0 mg/kg, sc), a 5-HT_1A antagonist WAY-101405 (0.1, 0.5 or 1.0 mg/kg, sc) or 0.9% saline solution on postpartum days …

Microrna Cluster Mir199a/214 Are Differentially Expressed In Female And Male Rats Following Nicotine Self-Administration, Steven T. Pittenger, Victoria L. Schaal, Dalia Moore, Rahul S. Guda, Sneh Koul, Sowmya V. Yelamanchili, Rick A. Bevins, Gurudutt Pendyala

Department of Psychology: Faculty Publications

Previous research has established sex differences associated with nicotine intake, however a significant gap in knowledge remains regarding the molecular mechanisms that govern these differences at the transcriptional level. One critical regulator of transcription are microRNAs (miRNAs). miRNAs are a family of non-coding RNAs that regulate an array of important biological functions altered in several disease states, including neuroadaptive changes within the brain associated with drug dependence. We examined the prefrontal cortex (PFC) from male and female Sprague-Dawley rats following self-administration (22 days) of nicotine or yoked saline controls using next generation RNA-Sequencing (RNA-Seq) technology and found an array of …

Individual Differences In Valence Bias: Fmri Evidence Of The Initial Negativity Hypothesis, Nathan M. Petro, Tien T. Tong, Daniel J. Henley, Maital Neta

Department of Psychology: Faculty Publications

Facial expressions offer an ecologically valid model for examining individual differences in affective decision-making. They convey an emotional signal from a social agent and provide important predictive information about one’s environment (presence of potential rewards or threats). Although some expressions provide clear predictive information (angry, happy), others (surprised) are ambiguous in that they predict both positive and negative outcomes. Thus, surprised faces can delineate an individual’s valence bias, or the tendency to interpret ambiguity as positive or negative. Our initial negativity hypothesis suggests that the initial response to ambiguity is negative, and that positivity relies on emotion regulation. We tested …

Age Of Migration Differentials In Life Expectancy With Cognitive Impairment: 20-Year Findings From The Hispanic-Epese, Marc A. Garcia, Joseph L. Saenz, Brian Downer, Chi-Tsun Chiu, Sunshine Rote, Rebeca Wong

Department of Sociology: Faculty Publications

Background and Objectives To examine differences in life expectancy with cognitive impairment among older Mexican adults according to nativity (U.S.-born/foreign-born) and among immigrants, age of migration to the United States.

Research Design and Methods This study employs 20 years of data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly to estimate the proportion of life spent cognitively healthy and cognitively impaired prior to death among older Mexican adults residing in the southwestern United States. We combine age-specific mortality rates with age-specific prevalence of cognitive impairment, defined as a Mini-Mental Status Exam score of less than 21 …

Characterization Of Solution-Phase Drug-Protein Interactions By Ultrafast Affinity Extraction, Sandya Beeram, Xiwei Zheng, Kyungah Suh, David S. Hage

Department of Chemistry: Faculty Publications

A number of tools based on high-performance affinity separations have been developed for studying drug-protein interactions. An example of one recent approach is ultrafast affinity extraction. This method has been employed to examine the free (or non-bound) fractions of drugs and other solutes in simple or complex samples that contain soluble binding agents. These free fractions have also been used to determine the binding constants and rate constants for the interactions of drugs with these soluble agents. This report describes the general principles of ultrafast affinity extraction and the experimental conditions under which it can be used to characterize such …

Systems And Methods For Actuating Soft Robotic Actuators, Robert F. Shepherd, Adam Stokes, Stephen A. Morin, Ludovico Cademartiri, Jacob Freake, Rui Nunes, Xin Chen, George M. Whitesides

Department of Chemistry: Faculty Publications

Systems and methods for providing a soft robot is provided. In one system , a robotic device includes a flexible body having a fluid chamber, where a portion of the flexible body includes an elastically extensible material and a portion of the flexible body is strain limiting relative to the elastically extensible material. The robotic device can further include a pressurizing inlet in fluid communication with the fluid chamber, and a pressurizing device in fluid communication with the pressurizing inlet, the pressurizing device including a reaction chamber configured to accommodate a gas producing chemical reaction for providing pressurized gas to …

Anatomy Of Stem Teaching In American Universities: A Snapshot From A Large-Scale Observation Study, Marilyne Stains, Jordan Harshman, Megan K. Barker, Stephanie V. Chasteen, Renee Cole, Sue Ellen Dechenne-Peters, M. Kevin Eagan Jr., Joan M. Esson, Jennifer K. Knight, Frank A. Laski, Marc Levis-Fitzgerald, Christopher J. Lee, Stanley M. Lo, Lisa M. Mcdonnell, Timothy A. Mckay, Nicole Michelotti, Michael S. Palmer, Kathryn M. Plank, Tamara M. Rodela, Erin R. Sanders, Natalie G. Schimpf, Patricia M. Schulte, Michelle Smith, Mackenzie Stetzer, Jackie Stewart, Blaire Van Valkenburgh, Erin Vinson, Laura K. Weir, Paul J. Wendel, Lindsay B. Wheeler, Anna M. Young

Department of Chemistry: Faculty Publications

National and local initiatives focused on the transformation of STEM teaching in higher education have multiplied over the last decade. These initiatives often focus on measuring change in instructional practices, but it is difficult to monitor such change without a national picture of STEM educational practices, especially as characterized by common observational instruments. We characterized a snapshot of this landscape by conducting the first large scale observation-based study. We found that lecturing was prominent throughout the undergraduate STEM curriculum, even in classrooms with infrastructure designed to support active learning, indicating that further work is required to reform STEM education. Additionally, …

Reductive Cleavage Of Organic Peroxides By Iron Salts And Thiols, Anderw Olson, Abigail J. Jameson, Shiva K. Kyasa, Boone W. Evans, Patrick H. Dussault

Department of Chemistry: Faculty Publications

Despite the low bond strength of the oxygen− oxygen bond, organic peroxides are often surprisingly resistant to cleavage by nucleophiles and reductants. As a result, achieving decomposition under mild conditions can be challenging. Herein, we explore the reactivity of a selection of peroxides toward thiolates, phenyl selenide, Fe(II) salts, and iron thiolates. Peroxides activated by conjugation, strain, or stereoelectronics are rapidly cleaved at room temperature by thiolate anions, phenylselenide, or Fe(II) salts. Under the same conditions, unhindered dialkyl peroxides are only marginally reactive; hindered peroxides, including triacetone triperoxide and diacetone diperoxide (DADP), are inert. In contrast, all but the most …