Recent Submissions

  • Unprotected peptide macrocyclization and stapling via a fluorine-thiol displacement reaction

    Islam, Md Shafiqul; Junod, Samuel L.; Zhang, Si; Buuh, Zakey Yusuf; Guan, Yifu; Zhao, Mi; Kaneria, Kishan H.; Kafley, Parmila; Cohen, Carson; Maloney, Robert; Lyu, Zhigang; Voelz, Vincent A.; Yang, Weidong; Wang, Rongsheng; Wang|0000-0002-5749-7447 (2022-01-17)
    We report the discovery of a facile peptide macrocyclization and stapling strategy based on a fluorine thiol displacement reaction (FTDR), which renders a class of peptide analogues with enhanced stability, affinity, cellular uptake, and inhibition of cancer cells. This approach enabled selective modification of the orthogonal fluoroacetamide side chains in unprotected peptides in the presence of intrinsic cysteines. The identified benzenedimethanethiol linker greatly promoted the alpha helicity of a variety of peptide substrates, as corroborated by molecular dynamics simulations. The cellular uptake of benzenedimethanethiol stapled peptides appeared to be universally enhanced compared to the classic ring-closing metathesis (RCM) stapled peptides. Pilot mechanism studies suggested that the uptake of FTDR-stapled peptides may involve multiple endocytosis pathways in a distinct pattern in comparison to peptides stapled by RCM. Consistent with the improved cell permeability, the FTDR-stapled lead Axin and p53 peptide analogues demonstrated enhanced inhibition of cancer cells over the RCM-stapled analogues and the unstapled peptides.
  • “Yeah, I Wrote That!”: Incorporating Critical Information Literacy to Build Community Inside and Outside of Wikipedia

    De Voe, Kristina; Shaw, Adrienne; De Voe|0000-0003-1590-3379; Shaw|0000-0001-5526-1839 (2021)
    In this chapter, we examine the relationship between open pedagogical practices and critical information literacy and how they intersect when Wikipedia is introduced in the classroom. Specifically, we discuss the collaboration between a librarian and a course instructor on iterations of Wikipedia assignments across three years and two classes. We unpack the importance of existing infrastructures, such as edit-a-thons and the WikiEdu dashboard, to support bringing Wikipedia assignments into the classroom. We also explore how we worked to connect course content to the renewable assignments and brought larger discussions of representation and community on Wikipedia into the classroom and assignments. Finally, we outline the lessons we learned through this collaboration. In sum, scaffolded projects allowed students to practice their contributions to Wikipedia in a supportive space and fostered critical engagement with course content. In their end-of-semester reflections, students stated that contributing to Wikipedia felt more meaningful and elicited feelings of pride that traditional, disposable assessments did not. They saw themselves as knowledge creators and scholarship creation as part of an ongoing conversation rather than an “end product.” By engaging in peer-review assignments, participating in edit-a-thons, and discussing the assignments with librarians who were not their professors, students also saw their work as part of a broader academic conversation. Through Wikipedia assignments, students can appreciate their own information privilege in terms of access to costly resources and become proactive in sharing that knowledge and their own growing expertise with a wider public.
  • Procrastination and the Shifting Political Media Environment: An Experimental Study of Media Choice Affecting a Democratic Outcome

    Ellithorpe, Morgan E.; Holbert, R. Lance; Palmer-Wackerly, Angela L. (2013-10-18)
    The shifting media environment is expected to have a variety of effects on political knowledge and behavior. An experimental study was conducted to assess the influence of media environment on news consumption, perceptions of media experience quality, and success on a political outcome. In addition, procrastination is introduced as a potentially important individual-difference variable with assessments offered for both its main effects and its ability to moderate the influence of media environment. Media environment complexity predicted lower news use and higher success on our political outcome. Procrastination’s effect was on media experience perceptions and a media environmentby-procrastination interaction on this portion of the hypothesized model. These outcomes then went on to predict success on a task analogous to democratic participation.
  • Developing a Normative Approach to Political Satire: An Empirical Perspective

    Holbert, R. Lance (2013)
    This article offers a formal normative assessment of political satire. It summarizes social scientific research on the influence of political satire and findings on the normative implications of political satire within a democratic framework. Two cogent lines of empirical research, persuasion and understanding, receive special attention. Political satire’s potential to generate normatively positive democratic effects is examined according to three competing theories of democracy: republicanism, pluralism, and elitism. Reports of its relatively small effect prevent clear normative judgments on satire as good or bad for democracy. However, its relationship to internal political self-efficacy merits further investigation. At the system level, political satire might generate significant normatively positive effects in the republican and elitist democratic frameworks. Examples of U.S. traditional political satire reveal the boundaries within which satire functions and their impact on the normative roles of this potentially important form of political discourse.
  • DICTION as a Tool for Studying the Mass Media

    Holbert, R. Lance (2014)
    This chapter offers a systematic assessment of DICTION’s ability to address a wide range of media content. Each of the media-related works in this volume reflects a unique mix of communication inputs, and DICTION proves itself able to generate valid and reliable insights on a diverse range of material. In addition, the chapter focuses on a series of challenges (e.g., Message Tailoring, Hypertext, Interactivity) and opportunities (e.g., big data) for DICTION in relation to the study of media content. The program and the researchers who utilize it need to continue to evolve with the changing media landscape in order to generate practical knowledge that is relevant to improving communication.
  • Putting the “self” in self-deprecation: When deprecating humor about minorities is acceptable

    Ellithorpe, Morgan E.; Esralew, Sarah; Holbert, R. Lance (2014-08-01)
    This study tested how source knowledge affects enjoyment of self- deprecating humor about a minority group. Participants made aware that the sourc of a message poking fun at people with disabilities was himself disabled had more positive evaluations of the cartoon and author than participants un-aware of his disability. Participants initially given no source information judged the author more positively the second time when they were given follow-up source information. Finally, some effects were moderated by the disability status of the message receiver, such that having a disability or knowing someone who does predicted higher liking of the cartoons when the author is disabled but lower liking when he is not. The results suggest a role for self-deprecating humor in intergroup relations, and predict when such humor will be accepted by mi-nority and non-minority group members.
  • Affinity for political humor: An assessment of internal factor structure, reliability, and validity

    Holbert, R. Lance; Lee, Jayeon; Esralew, Sarah; Walther, Whitney O.; Hmielowski, Jay D.; Landreville, Kristen D. (2013-10-19)
    An 11-item Affinity for Political Humor (AFPH) scale is theorized as a higher-order latent factor with four lower-order latent factors (incongruity, superiority, anxiety reduction, and social connection). The theorized measurement model and several alternative models are tested using confirmatory factor analysis (CFA). In addition, reliability and validity assessments are provided. Analyses are conducted using four data sets collected between December 2009 and March 2011 (total N = 1860). Results reveal the theorized model to fit the data well, but also indicate that an alternative model (four lower-order latent variables only) retains the strongest and most consistent fit across all four data sets. Reliability assessments reveal strong internal consistency for the 11-item AFPH scale, as well as for each of the four sub-dimensions. In addition, correlational analyses reveal the AFPH measures to retain strong validity (i.e., statistically significant and positive correlations with political TV satire consumption).
  • Political Satire: Defining a Nebulous Construct

    Holbert, R. Lance (2014)
    Political satire is a complex form of political discourse that is evident in democratic media systems across the globe. Its diversity has led many to argue that it is impossible to put forward a proper definition that encompasses all of its seemingly infinite permutations, and all extant attempts to define this unwieldy concept have been met with much criticism. Not one communicative act can be studied and understood properly without being well defined. Studies of political satire are on the rise and much knowledge has been generated over the last decade. However, these lines of research will fall into stagnation if the central communication construct driving these efforts is not explicated with the necessary precision. This essay offers a comprehensive definition of political satire in an effort to create a foundation from which this area of study can continue to flourish.
  • Political Para-Social Relationship as a Predictor of Voting Preferences in the Israeli 2019 Elections

    Tsfati, Yariv; Dvir-Gvirsman, Shira; Tsuriel, Keren; Waismel-Manor, Israel; Holbert, R. Lance (2021-07-30)
    The idea that the success of media personae in attracting audiences and maintaining their loyalty depends on the creation of a pseudo-friendship, known as para-social relationships, has been a mainstay of mass media research for more than half a century. Expanding the scope of para-social relationship research into the political realm, the notion that political support could be predicted based on the intensity of para-social relationships between voters and political figures was demonstrated in a recent study. The current exploration tests the predictive power of Political Para-Social Relationship (PPSR) in the context of the April and September 2019 Israeli election campaigns. Findings from online panel data (n = 1,061) demonstrate that PPSR toward Netanyahu was a positive predictor of voting for Netanyahu’s Likud party and a negative predictor of voting for opposition leader Benny Gantz’s Blue and White party in both campaigns. The opposite was true for PPSR toward Benny Gantz. The PPSR constructs also predicted shifts in party support from the February to October (post-election) waves of the study, and loyalty toward the parties. In all models, the PPSR constructs were among the strongest predictors of political support.
  • A Treatment-Based Classification Approach to Examination and Intervention of Lumbar Disorders

    Burns, Scott; Foresman, Edward; Kraycsir, Stephenie J.; Egan, William; Glynn, Paul; Mintken, Paul E.; Cleland, Joshua A.; Burns|0000-0002-7510-6200 (2011-06-01)
    Context: Low back injuries are a common occurrence in athletes and often result in missed competition and practice time. The examination of athletes with low back pain commonly involves diagnostic imaging, which rarely guides the clinician in selecting the appropriate interventions. Data Acquisition: All years of PubMed, CINAHL, PEDro, and SPORTDiscus were searched in December 2010. Keywords included treatment based classification and lumbar with the following terms: rehabilitation, treatment, athlete, low back pain, sports, and outcomes. Results: A treatment-based classification approach is preferred for the management of the athlete with low back pain. The treatment-based classification approach involves 3 steps. First is to screen the patient for potentially serious conditions that are not appropriate for conservative management. Second is staging the athlete (based on current disability ratings and ability to perform functional activities). Finally, treatment interventions are selected on the basis of the athlete’s signs and symptoms. Conclusion: The treatment-based classification scheme provides the clinician with a reliable algorithm for matching an athlete’s symptom presentation to the optimal intervention, potentially reducing participation loss. Managing individuals with low back pain using a treatment-based classification approach significantly reduces disability and pain compared with current clinical practice guideline standards.
  • Coxa-vertebral Syndrome and its Significance in Hip Arthroplasty

    Denisov, A. O.; Shilnikov, V. A.; Burns, Scott; Burns|0000-0002-7510-6200 (2012)
    Lumbosacral spine and hip joints is a complex physiological functions of the co-operation of a large number of anatomical structures. Lesions of the links in the system can mutually afflict each other. Combined pathology of the hip and lumbosacral spine is called hip-spine syndrome, or coxa-vertebral syndrome. Symptoms of the joint and spine are very similar and only a careful examination and clinical examination may find the differences. As the disease progresses the hip increases the restriction of movement, there is a contracture of the limbs in a vicious position, which leads to an increase in tilt of the pelvis, increased lumbar lordosis and to functional shortening of limbs on the affected side. This gives rise to functional impairment, and then strain the joints of his spine and disease - osteochondrosis and scoliosis. After the successful operation of total hip replacement is often progressive clinical lesions of vertebral segment, which is manifested pain and is often offset by the results of arthroplasty as the restoration of movement in the hip joint, and the change in length limb after arthroplasty leads to rupture formed a functional stereotype change in the mobility of the lumbar spine, pelvis regression bias that causes the dynamic compression spinal nerve root. Depending on the duration of the existence, severity and nature of changes in the pelvic girdle is suitable correction of equipment replacement surgery, including, for example, in some cases, deliberate shortening or lengthening the preservation of the lower extremity, offset change, etc.
  • Examination procedures and interventions for the hip in the management of low back pain: a survey of physical therapists

    Burns, Scott; Cleland, Joshua A.; Rivett, Darren A.; Snodgrass, Suzanne J.; Burns|0000-0002-7510-6200 (2018-10-02)
    Objectives: The main research aims were to investigate whether physical therapists are examining the hip(s) in individuals with a primary complaint of low back pain (LBP) and if so, the interventions being provided that target the hip(s). Methods: An anonymous electronic survey was distributed to the membership of the American Physical Therapy Association Orthopaedic and Sports Sections, as well as that of the American Academy of Orthopaedic Manual Physical Therapists. Participant demographics and survey responses were analyzed using descriptive statistics. Associations between variables were examined using chi-square analysis. Results: The estimated response rate was 18.4% (n = 1163, mean age 40.5 ± 11.4 years). The majority of respondents (91%, n = 1059) reported they always or most of the time examined the hip(s) in individuals with LBP. The most common examination items utilized were hip strength testing (94%, n = 948), passive range of motion (91%, n = 921) and muscle flexibility testing (90%, n = 906). The most common interventions included hip strengthening (94%, n = 866) and hip flexibility exercises (90%, n = 814). Respondents enrolled in or having completed a post-professional fellowship were more likely to utilize hip joint manual therapy techniques (x2 = 25.3, p = <0.001) and less likely to prescribe hip flexibility exercises (x2 = 7.9, p = 0.005) or use electrophysical modalities (x2 = 4.3, p = 0.039). Conclusions: Physical therapists commonly examine and provide interventions directed at the hip(s) for individuals with LBP. Post-professional fellowship training appears to influence the intervention selection of the physical therapist, with an increase in usage of hip joint manual therapy and a decrease in hip muscle flexibility and modality usage.
  • Effectiveness of physical therapy interventions for low back pain targeting the low back only or low back plus hips: a randomized controlled trial protocol

    Burns, Scott; Cleland, Joshua A.; Rivett, Darren A.; Snodgrass, Suzanne J.; Burns|0000-0002-7510-6200 (2018-09-07)
    Background: Recent evidence suggests that physical therapy interventions targeting the hips may improve outcomes, including pain and disability, for patients with low back pain (LBP). Currently, there is conflicting data in regard to whether an individual with LBP needs to have a concurrent hip impairment in order to respond to this approach. The purpose of this clinical trial will be to determine the short and long-term effectiveness of physical therapy interventions directed at the lumbar spine only, versus lumbar spine and hip(s), in individuals with a primary complaint of LBP with a concurrent hip impairment. Methods: A multi-center, randomized controlled trial of 76 adult individuals with a primary complaint of LBP, who also have at least one concurrent hip impairment. Participants will be randomized into the ‘LBP only’ or ‘LBP + Hip’ group. Treatment to the low back in both groups will be a pragmatic approach consisting of interventions targeting the low back without targeting the hip(s). Participants randomized to the LBP + Hip group will also receive a semi-prescriptive set of manual therapy and exercise techniques that target the hips. The primary outcome measures will be the modified Oswestry Disability Index and the Numeric Pain Rating Scale at discharge. Discussion: These two treatment strategies are commonly utilized in physical therapy practice, but there is uncertainty which is superior. This trial will also help to provide a better understanding of the role of concurrent hip impairments in LBP.
  • Total vertical sediment flux and PM10 emissions from disturbed Chihuahuan Desert surfaces

    Baddock, Matthew C.; Zobeck, Ted M.; D'Odorico, Paolo; Ravi, Sujith; Bhattachan, Abinash; Van Pelt, R. Scott; Ravi|0000-0002-0425-9373 (2017-01-31)
    Desert surfaces are typically stable and represent some of the longest-lived landforms on Earth. For surfaces devoid of vegetation, the evolution of a desert pavement of gravel and small stones protects the surface from erosion by wind and water and vegetation further protects the surface in arid and semi-arid rangelands. The susceptibility of the land surface to wind erosion is enhanced by mechanical damage to the desert pavement or vegetation losses resulting from fire or grazing. Despite the relatively rich literature on the effects of grazing and fire on plant community composition, land degradation, and the productivity of arid landscapes, little is known about the effects of moderate grazing or fire on the erodibility of soils in desert grasslands and shrublands. Here we investigate the effects of simulated moderate grazing, simulated livestock trampling, and of fire on the resulting wind erodibility and dust emissions of the affected soil surfaces. We surveyed 24 plots of the same size, 6 m × 0.6 m, at a research site in the northern Chihuahuan Desert including 6 plots in a shrub-grass ecotone, 12 plots in an adjacent grassland, and 6 plots in an area that had been burned by a natural wildfire 6 months earlier but had no vegetation recovery due to the time of year and drought. To evaluate the various effects of disturbances on the susceptibility of the surface to wind erosion and dust entrainment, replicates of three plots underwent different treatments including clipping, trampling, fire, and tillage. We subsequently tested each of the treated plots with a portable field wind tunnel run at 12.6 m s− 1. We found that moderate grazing and fire did not result in great soil loss in desert grasslands but that shrublands were more seriously affected by grazing and fire. Total removal of vegetation and disturbance of the soil surface did result in greater than order of magnitude increases of vertical sediment flux and greater than three-fold increases of dust emissions.
  • Changes in spatial variance during a grassland to shrubland state transition

    Ratajczak, Zak; D'Odorico, Paolo; Nippert, Jesse B.; Collins, Scott L.; Brunsell, Nathaniel A.; Ravi, Sujith; Ravi|0000-0002-0425-9373 (2016-11-05)
  • Ecohydrological interactions within “fairy circles” in the Namib Desert: Revisiting the self-organization hypothesis

    Ravi, Sujith; Wang, Lixin; Kaseke, Kudzai Farai; Buynevich, Ilya V.; Marais, Eugene; Ravi|0000-0002-0425-9373 (2017-02-04)
    Vegetation patterns such as rings, bands, and spots are recurrent characteristics of resource-limited arid and semiarid ecosystems. One of the most recognizable vegetation patterns is the millions of circular patches, often referred to as “fairy circles,” within the arid grassland matrix extending over hundreds of kilometers in the Namib Desert. Several modeling studies have highlighted the role of plant-soil interactions in the formation of these fairy circles. However, little is known about the spatial and temporal variabilities of hydrological processes inside a fairy circle. In particular, a detailed field assessment of hydrological and soil properties inside and outside the fairy circles is limited. We conducted extensive measurements of infiltration rate, soil moisture, grass biometric, and sediment grain-size distribution from multiple circles and interspaces in the Namib Desert. Our results indicate that considerable heterogeneity in hydrological processes exists within the fairy circles, resulting from the presence of coarser particles in the inner bare soil areas, whereas concentration of fine soil occurs on the vegetated edges. The trapping of aeolian and water-borne sediments by plants may result in the observed soil textural changes beneath the vegetation, which in turn, explains the heterogeneity in hydrological processes such as infiltration and runoff. Our investigation provides new insights and experimental data on the ecohydrological processes associated with fairy circles, from a less studied location devoid of sand termite activity within the circles. The results seem to provide support to the “self-organization hypothesis” of fairy circle formation attributed to the antiphase spatial biomass-water distributions.
  • Dynamic interactions of ecohydrological and biogeochemical processes in water-limited systems

    Wang, Lixin; Manzoni, Stefano; Ravi, Sujith; Riveros-Iregui, Diego; Caylor, Kelly; Ravi|0000-0002-0425-9373 (2015-08-07)
    Water is the essential reactant, catalyst, or medium for many biogeochemical reactions, thus playing an important role in the activation and deactivation of biogeochemical processes. The coupling between hydrological and biogeochemical processes is particularly evident in water-limited arid and semi-arid environments, but also in areas with strong seasonal precipitation patterns (e.g., Mediterranean) or in mesic systems during droughts. Moreover, this coupling is apparent at all levels in the ecosystems—from soil microbial cells to whole plants to landscapes. Identifying and quantifying the biogeochemical “hot spots” and “hot moments”, the underlying hydrological drivers, and how disturbance-induced vegetation transitions affect the hydrological-biogeochemical interactions are challenging because of the inherent complexity of these interactions, thus requiring interdisciplinary approaches. At the same time, a holistic approach is essential to fully understand function and processes in water-limited ecosystems and to predict their responses to environmental change. This article examines some of the mechanisms responsible for microbial and vegetation responses to moisture inputs in water-limited ecosystems through a synthesis of existing literature. We begin with the initial observation of Birch effect in 1950s and examine our current understanding of the interactions among vegetation dynamics, hydrology, and biochemistry over the past 60 years. We also summarize the modeling advances in addressing these interactions. This paper focuses on three opportunities to advance coupled hydrological and biogeochemical research: (1) improved quantitative understanding of mechanisms linking hydrological and biogeochemical variations in drylands, (2) experimental and theoretical approaches that describe linkages between hydrology and biogeochemistry (particularly across scales), and (3) the use of these tools and insights to address critical dryland issues of societal relevance.
  • Convergent vegetation fog and dew water use in the Namib Desert

    Wang, Lixin; Farai Kaseke, Kudzai; Ravi, Sujith; Jiao, Wenzhe; Mushi, Roland; Shuuya, Titus; Maggs-Kolling, Gillian; Ravi|0000-0002-0425-9373 (2019-06-18)
    Nonrainfall water inputs (e.g., fog and dew) are the least studied hydrological components in ecohydrology. The importance of nonrainfall waters on vegetation water status in arid ecosystems is receiving increasing attention. However, a clear understanding on how common plant water status benefits from nonrainfall waters, the impacts of different types of fog and dew events on vegetation water status, and the vegetation uptake mechanisms of nonrainfall waters is still lacking. In this study, we used concurrent leaf and soil water potential measurements from 3 years to investigate the species-specific capacity to utilize moisture from fog and dew within the Namib Desert. Eight common plant species in the Namib Desert were selected. Our results showed that both fog and dew significantly increased soil water potential. Seven of the eight plant species studied responded to fog and dew events, although the magnitude of the response differed. Plants generally showed stronger responses to fog than to dew. Fog timing seemed to be an important factor determining vegetation response; for example, night fog did not affect plant water potential. We also found that Euclea pseudebenus and Faidherbia albida likely exploit fog moisture through foliar uptake. This study provides a first comprehensive assessment of the effects of nonrainfall waters on plant water status within the Namib Desert. Furthermore, this study highlights the importance of concurrent leaf and soil water potential measurements to identify the pathways of nonrainfall water use by desert vegetation. Our results fill a knowledge gap in dryland ecohydrology and have important implications for other drylands.
  • Quantifying Postfire Aeolian Sediment Transport Using Rare Earth Element Tracers

    Dukes, David; Gonzales, Howell B.; Ravi, Sujith; Grandstaff, David; Van Pelt, R. Scott; Li, Junran; Wang, Guan; Sankey, Joel B.; Ravi|0000-0002-0425-9373; Grandstaff|0000-0003-3384-1570 (2018-01-15)
    Grasslands, which provide fundamental ecosystem services in many arid and semiarid regions of the world, are undergoing rapid increases in fire activity and are highly susceptible to postfire-accelerated soil erosion by wind. A quantitative assessment of physical processes that integrates fire-wind erosion feedbacks is therefore needed relative to vegetation change, soil biogeochemical cycling, air quality, and landscape evolution. We investigated the applicability of a novel tracer technique—the use of multiple rare earth elements (REE)—to quantify soil transport by wind and to identify sources and sinks of wind-blown sediments in both burned and unburned shrub-grass transition zone in the Chihuahuan Desert, NM, USA. Results indicate that the horizontal mass flux of wind-borne sediment increased approximately threefold following the fire. The REE tracer analysis of wind-borne sediments shows that the source of the horizontal mass flux in the unburned site was derived from bare microsites (88.5%), while in the burned site it was primarily sourced from shrub (42.3%) and bare (39.1%) microsites. Vegetated microsites which were predominantly sinks of aeolian sediments in the unburned areas became sediment sources following the fire. The burned areas showed a spatial homogenization of sediment tracers, highlighting a potential negative feedback on landscape heterogeneity induced by shrub encroachment into grasslands. Though fires are known to increase aeolian sediment transport, accompanying changes in the sources and sinks of wind-borne sediments may influence biogeochemical cycling and land degradation dynamics. Furthermore, our experiment demonstrated that REEs can be used as reliable tracers for field-scale aeolian studies.

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