Real-Time Detection of Strawberry Ripeness Using Augmented Reality and Deep Learning.

Currently, strawberry harvesting relies heavily on human labour and subjective assessments of ripeness, resulting in inconsistent post-harvest quality. Therefore, the aim of this work is to automate this process and provide a more accurate and efficient way of assessing ripeness. We explored a unique combination of YOLOv7 object detection and augmented reality technology to detect and visualise the ripeness of strawberries. Our results showed that the proposed YOLOv7 object detection model, which employed transfer learning, fine-tuning and multi-scale training, accurately identified the level of ripeness of each strawberry with an mAP of 0.89 and an F1 score of 0.92. The tiny models have an average detection time of 18 ms per frame at a resolution of 1280 × 720 using a high-performance computer, thereby enabling real-time detection in the field. Our findings distinctly establish the superior performance of YOLOv7 when compared to other cutting-edge methodologies. We also suggest using Microsoft HoloLens 2 to overlay predicted ripeness labels onto each strawberry in the real world, providing a visual representation of the ripeness level. Despite some challenges, this work highlights the potential of augmented reality to assist farmers in harvesting support, which could have significant implications for current agricultural practices.

Two-Year Outcomes After Minimally Invasive Surfactant Therapy in Preterm Infants: Follow-Up of the OPTIMIST-A Randomized Clinical Trial.

Importance: The long-term effects of surfactant administration via a thin catheter (minimally invasive surfactant therapy [MIST]) in preterm infants with respiratory distress syndrome remain to be definitively clarified. Objective: To examine the effect of MIST on death or neurodevelopmental disability (NDD) at 2 years' corrected age. Design, Setting, and Participants: Follow-up study of a randomized clinical trial with blinding of clinicians and outcome assessors conducted in 33 tertiary-level neonatal intensive care units in 11 countries. The trial included 486 infants with a gestational age of 25 to 28 weeks supported with continuous positive airway pressure (CPAP). Collection of follow-up data at 2 years' corrected age was completed on December 9, 2022. Interventions: Infants assigned to MIST (n = 242) received exogenous surfactant (200 mg/kg poractant alfa) via a thin catheter; those assigned to the control group (n = 244) received sham treatment. Main Outcomes and Measures: The key secondary outcome of death or moderate to severe NDD was assessed at 2 years' corrected age. Other secondary outcomes included components of this composite outcome, as well as hospitalizations for respiratory illness and parent-reported wheezing or breathing difficulty in the first 2 years. Results: Among the 486 infants randomized, 453 had follow-up data available (median gestation, 27.3 weeks; 228 females [50.3%]); data on the key secondary outcome were available in 434 infants. Death or NDD occurred in 78 infants (36.3%) in the MIST group and 79 (36.1%) in the control group (risk difference, 0% [95% CI, -7.6% to 7.7%]; relative risk [RR], 1.0 [95% CI, 0.81-1.24]); components of this outcome did not differ significantly between groups. Secondary respiratory outcomes favored the MIST group. Hospitalization with respiratory illness occurred in 49 infants (25.1%) in the MIST group vs 78 (38.2%) in the control group (RR, 0.66 [95% CI, 0.54-0.81]) and parent-reported wheezing or breathing difficulty in 73 (40.6%) vs 104 (53.6%), respectively (RR, 0.76 [95% CI, 0.63-0.90]). Conclusions and Relevance: In this follow-up study of a randomized clinical trial of preterm infants with respiratory distress syndrome supported with CPAP, MIST compared with sham treatment did not reduce the incidence of death or NDD by 2 years of age. However, infants who received MIST had lower rates of adverse respiratory outcomes during their first 2 years of life. Trial Registration: anzctr.org.au Identifier: ACTRN12611000916943.

Pilot study to assess prolonged overnight fasting in breast cancer survivors (longfast).

PURPOSE: Retrospective analysis of nightly fasting among women with breast cancer suggests that fasting < 13 h may be associated with a higher risk of breast cancer recurrence. We sought to evaluate prolonged overnight fasting (POF), an accessible nonpharmacological intervention, in a prospective feasibility study. METHODS: We designed a single-arm, pilot study to evaluate the feasibility of fasting for 13 h overnight for 12 weeks among women with a history of early-stage breast cancer survivors. Baseline and end of study assessments included measurements of body mass index (BMI), blood biomarkers, quality of life (QOL), mood, fatigue, and physical activity. Patient-reported outcome questionnaires were also administered at 6 weeks. Feasibility was defined as ≥ 60% of participants documenting fasting for 13 h on at least 70% of nights during the study period. RESULTS: Forty women with a history of breast cancer were enrolled with a median age of 60 (range 35-76) and median time since diagnosis of 4.5 years (range 0.8-20.7). At baseline, BMI was ≥ 25 in 37.5%. Ninety-five percent of participants fasted ≥ 13 h for at least 70% of study days (95% CI 83-99%). There was a statistically significant improvement in anxiety (p = 0.0007) at 6 weeks and BMI (p = 0.0072), anxiety (p = 0.0141), depression (p = 0.0048), and fatigue (p = 0.0105) at 12 weeks. There was no significant change in overall QOL, physical activity levels, or blood biomarkers at 12 weeks. CONCLUSIONS: POF is feasible among patients with a history of breast cancer and may potentially improve BMI, mood, and fatigue without detrimental effects on overall QOL.

Trends of Augmented Reality for Agri-Food Applications.

Recent years have witnessed an increasing interest in deploying state-of-the-art augmented reality (AR) head-mounted displays (HMDs) for agri-food applications. The benefits of AR HMDs to agri-food industry stakeholders (e.g., food suppliers, retail/food service) have received growing attention and recognition. AR HMDs enable users to make healthier dietary choices, experience novel changes in their perception of taste, enhance the cooking and food shopping experience, improve productivity at work and enhance the implementation of precision farming. Therefore, although development costs are still high, the case for integration of AR in food chains appears to be compelling. This review will present the most recent developments of AR HMDs for agri-food relevant applications. The summarized applications can be clustered into different themes: (1) dietary and food nutrition assessment; (2) food sensory science; (3) changing the eating environment; (4) retail food chain applications; (5) enhancing the cooking experience; (6) food-related training and learning; and (7) food production and precision farming. Limitations of current practices will be highlighted, along with some proposed applications.

Effect of Minimally Invasive Surfactant Therapy vs Sham Treatment on Death or Bronchopulmonary Dysplasia in Preterm Infants With Respiratory Distress Syndrome: The OPTIMIST-A Randomized Clinical Trial.

Importance: The benefits of surfactant administration via a thin catheter (minimally invasive surfactant therapy [MIST]) in preterm infants with respiratory distress syndrome are uncertain. Objective: To examine the effect of selective application of MIST at a low fraction of inspired oxygen threshold on survival without bronchopulmonary dysplasia (BPD). Design, Setting, and Participants: Randomized clinical trial including 485 preterm infants with a gestational age of 25 to 28 weeks who were supported with continuous positive airway pressure (CPAP) and required a fraction of inspired oxygen of 0.30 or greater within 6 hours of birth. The trial was conducted at 33 tertiary-level neonatal intensive care units around the world, with blinding of the clinicians and outcome assessors. Enrollment took place between December 16, 2011, and March 26, 2020; follow-up was completed on December 2, 2020. Interventions: Infants were randomized to the MIST group (n = 241) and received exogenous surfactant (200 mg/kg of poractant alfa) via a thin catheter or to the control group (n = 244) and received a sham (control) treatment; CPAP was continued thereafter in both groups unless specified intubation criteria were met. Main Outcomes and Measures: The primary outcome was the composite of death or physiological BPD assessed at 36 weeks' postmenstrual age. The components of the primary outcome (death prior to 36 weeks' postmenstrual age and BPD at 36 weeks' postmenstrual age) also were considered separately. Results: Among the 485 infants randomized (median gestational age, 27.3 weeks; 241 [49.7%] female), all completed follow-up. Death or BPD occurred in 105 infants (43.6%) in the MIST group and 121 (49.6%) in the control group (risk difference [RD], -6.3% [95% CI, -14.2% to 1.6%]; relative risk [RR], 0.87 [95% CI, 0.74 to 1.03]; P = .10). Incidence of death before 36 weeks' postmenstrual age did not differ significantly between groups (24 [10.0%] in MIST vs 19 [7.8%] in control; RD, 2.1% [95% CI, -3.6% to 7.8%]; RR, 1.27 [95% CI, 0.63 to 2.57]; P = .51), but incidence of BPD in survivors to 36 weeks' postmenstrual age was lower in the MIST group (81/217 [37.3%] vs 102/225 [45.3%] in the control group; RD, -7.8% [95% CI, -14.9% to -0.7%]; RR, 0.83 [95% CI, 0.70 to 0.98]; P = .03). Serious adverse events occurred in 10.3% of infants in the MIST group and 11.1% in the control group. Conclusions and Relevance: Among preterm infants with respiratory distress syndrome supported with CPAP, minimally invasive surfactant therapy compared with sham (control) treatment did not significantly reduce the incidence of the composite outcome of death or bronchopulmonary dysplasia at 36 weeks' postmenstrual age. However, given the statistical uncertainty reflected in the 95% CI, a clinically important effect cannot be excluded. Trial Registration: anzctr.org.au Identifier: ACTRN12611000916943.

Crowded environments reduce spatial memory in older but not younger adults.

Previous studies have reported an age-related decline in spatial abilities. However, little is known about whether the presence of other, task-irrelevant stimuli during learning further affects spatial cognition in older adults. Here we embedded virtual environments with moving crowds of virtual human pedestrians (Experiment 1) or objects (Experiment 2) whilst participants learned a route and landmarks embedded along that route. In subsequent test trials we presented clips from the learned route and measured spatial memory using three different tasks: a route direction task (i.e. whether the video clip shown was a repetition or retracing of the learned route); an intersection direction task; and a task involving identity of the next landmark encountered. In both experiments, spatial memory was tested in two separate sessions: first following learning of an empty maze environment and second using a different maze which was populated. Older adults performed worse than younger adults in all tasks. Moreover, the presence of crowds during learning resulted in a cost in performance to the spatial tasks relative to the 'no crowds' condition in older adults but not in younger adults. In contrast, crowd distractors did not affect performance on the landmark sequence task. There was no age-related cost on performance with object distractors. These results suggest that crowds of human pedestrians selectively capture older adults' attention during learning. These findings offer further insights into how spatial memory is affected by the ageing process, particularly in scenarios which are representative of real-world situations.

Multisensory aversive stimuli differentially modulate negative feelings in near and far space.

Affect, space, and multisensory integration are processes that are closely linked. However, it is unclear whether the spatial location of emotional stimuli interacts with multisensory presentation to influence the emotional experience they induce in the perceiver. In this study, we used the unique advantages of virtual reality techniques to present potentially aversive crowd stimuli embedded in a natural context and to control their display in terms of sensory and spatial presentation. Individuals high in crowdphobic fear navigated in an auditory-visual virtual environment, in which they encountered virtual crowds presented through the visual channel, the auditory channel, or both. They reported the intensity of their negative emotional experience at a far distance and at a close distance from the crowd stimuli. Whereas auditory-visual presentation of close feared stimuli amplified negative feelings, auditory-visual presentation of distant feared stimuli did not amplify negative feelings. This suggests that spatial closeness allows multisensory processes to modulate the intensity of the emotional experience induced by aversive stimuli. Nevertheless, the specific role of auditory stimulation must be investigated to better understand this interaction between multisensory, affective, and spatial representation processes. This phenomenon may serve the implementation of defensive behaviors in response to aversive stimuli that are in position to threaten an individual's feeling of security.

Familiar environments enhance object and spatial memory in both younger and older adults.

Recent evidence suggests that familiarity with an environment may protect against spatial memory decline for familiar objects in older adults. We investigated whether a familiar context also reduces age-related decline in spatial memory for novel objects. Twenty-four younger and 23 older participants viewed a virtual rendering of a local environment along two different routes, each through a well-known (West) or lesser-known (East) area within the environment. Older and younger participants reported being more familiar with one (i.e. West) area than the other. In each trial, participants were presented with one route and were instructed to learn ten novel objects and their locations along the route. Following learning, participants immediately completed five test blocks: an object recognition task, an egocentric spatial processing (direction judgement) task, an allocentric spatial processing (proximity judgement) task and two pen-and-paper tests to measure cognitive mapping abilities. First we found an age effect with worse performance by older than younger adults in all spatial tasks, particularly in allocentric spatial processing. However, our results suggested better memory for objects and directions, but not proximity judgements, when the task was associated with more familiar than unfamiliar contexts, in both age groups. There was no benefit of context when a separate young adult group (N = 24) was tested, who reported being equally familiar with both areas. These results suggest an important facilitatory role of context familiarity on object recognition, and in particular egocentric spatial memory, and have implications for enhancing spatial memory in older adults.

CT53518, a novel selective FLT3 antagonist for the treatment of acute myelogenous leukemia (AML).

Up to 30% of acute myelogenous leukemia (AML) patients harbor an activating internal tandem duplication (ITD) within the juxtamembrane domain of the FLT3 receptor, suggesting that it may be a target for kinase inhibitor therapy. For this purpose we have developed CT53518, a potent antagonist that inhibits FLT3, platelet-derived growth factor receptor (PDGFR), and c-Kit (IC(50) approximately 200 nM), while other tyrosine or serine/threonine kinases were not significantly inhibited. In Ba/F3 cells expressing different FLT3-ITD mutants, CT53518 inhibited IL-3-independent cell growth and FLT3-ITD autophosphorylation with an IC(50) of 10-100 nM. In human FLT3-ITD-positive AML cell lines, CT53518 induced apoptosis and inhibited FLT3-ITD phosphorylation, cellular proliferation, and signaling through the MAP kinase and PI3 kinase pathways. Therapeutic efficacy of CT53518 was demonstrated both in a nude mouse model and in a murine bone marrow transplant model of FLT3-ITD-induced disease.

"CityQuest," A Custom-Designed Serious Game, Enhances Spatial Memory Performance in Older Adults.

Spatial cognition is known to decline with aging. However, little is known about whether training can reduce or eliminate age-related deficits in spatial memory. We investigated whether a custom-designed video game involving spatial navigation, obstacle avoidance, and balance control would improve spatial memory in older adults. Specifically, 56 healthy adults aged 65 to 84 years received 10 sessions of multicomponent video game training, based on a virtual cityscape, over 5 weeks. Participants were allocated to one of three training conditions: the main intervention, the "CityQuest" group (n = 19), and two control groups, spatial navigation without obstacle avoidance ("Spatial Navigation-only" group, n = 21) and obstacle avoidance without spatial navigation ("Obstacles-only" group, n = 15). Performance on object recognition, egocentric and allocentric spatial memory (incorporating direction judgment tasks and landmark location tasks, respectively), navigation strategy preference, and executive functioning was assessed in pre- and post-intervention sessions. The results showed an overall benefit on performance in a number of spatial memory measures and executive function for participants who received spatial navigation training, particularly the CityQuest group, who also showed significant improvement on the landmark location task. However, there was no evidence of a shift from egocentric to allocentric strategy preference. We conclude that spatial memory in healthy older participants is amenable to improvement with training over a short term. Moreover, technology based on age-appropriate, multicomponent video games may play a key role in cognitive training in older adults.

Proceedings from the ice hockey summit on concussion: a call to action.

OBJECTIVE: The objective of this proceeding is to integrate the concussion in sport literature and sport science research on safety in ice hockey to develop an action plan to reduce the risk, incidence,severity, and consequences of concussion in ice hockey. methods: A rationale paper outlining a collaborative action plan to address concussions in hockey was posted for review two months prior to the Ice Hockey Summit: Action on Concussion. Focused presentations devoted specifically to concussion in ice hockey were presented during the Summit and break out sessions were used to develop strategies to reduce concussion in the sport. This proceedings and a detailed scientific review (a matrix of solutions) were written to disseminate the evidence based information and resulting concussion reduction strategies. The manuscripts were reviewed by the authors, advisors and contributors to ensure that the opinions and recommendations reflect the current level of knowledge on concussion in hockey. RESULTS: Six components of a potential solution were articulated in the Rationale paper and became the topics for breakout groups that followed the professional, scientific lectures. Topics that formed the core of the action plan were: metrics and databases; recognizing,managing, and return to play; hockey equipment and ice arenas;prevention and education; rules and regulations; and expedient communication of the outcomes. The attendees in breakout sessions identified action items for each section. The most highly ranked action items were brought to a vote in the open assembly, using an Audience Response System (ARS). The strategic planning process was conducted to assess: Where are we at?; Where must we get to?; and What strategies are necessary to make progress on the prioritized action items? CONCLUSIONS: Three prioritized action items for each component of the solution and the percentage of the votes received are listed in the body of this proceeding.

Resources and practices to help graduate students and postdoctoral fellows write statements of teaching philosophy.

Graduate students and postdoctoral fellows currently encounter requests for a statement of teaching philosophy in at least half of academic job announcements in the United States. A systematic process for the development of a teaching statement is required that integrates multiple sources of support, informs writers of the document's purpose and audience, helps writers produce thoughtful statements, and encourages meaningful reflection on teaching and learning. This article for faculty mentors and instructional consultants synthesizes practices for mentoring graduate students, postdoctoral fellows, and junior faculty members as they prepare statements of teaching philosophy. We review background information on purposes and audiences, provide writing resources, and synthesize empirical research on the use of teaching statements in academic job searches. In addition, we integrate these resources into mentoring processes that have helped graduate students in a Health Sciences Pedagogy course to collaboratively and critically examine and write about their teaching. This summary is intended for faculty mentors and instructional consultants who want to refine current resources or establish new mentoring programs. This guide also may be useful to graduate students, postdoctoral fellows, and junior faculty members, especially those who lack mentoring or who seek additional resources, as they consider the many facets of effective teaching.

Proceedings from the Ice Hockey Summit on Concussion: a call to action.

OBJECTIVE: The objective of this proceeding is to integrate the concussion in sport literature and sport science research on safety in ice hockey to develop an action plan to reduce the risk, incidence, severity, and consequences of concussion in ice hockey. METHODS: A rationale paper outlining a collaborative action plan to address concussions in hockey was posted for review two months prior to the Ice Hockey Summit: Action on Concussion. Focused presentations devoted specifically to concussion in ice hockey were presented during the Summit and breakout sessions were used to develop strategies to reduce concussion in the sport. This proceedings and a detailed scientific review (a matrix of solutions) were written to disseminate the evidence-based information and resulting concussion reduction strategies. The manuscripts were reviewed by the authors, advisors and contributors to ensure that the opinions and recommendations reflect the current level of knowledge on concussion in hockey. RESULTS: Six components of a potential solution were articulated in the Rationale paper and became the topics for breakout groups that followed the professional, scientific lectures. Topics that formed the core of the action plan were: metrics and databases; recognizing, managing and return to play; hockey equipment and ice arenas; prevention and education; rules and regulations; and expedient communication of the outcomes. The attendees in breakout sessions identified action items for each section. The most highly ranked action items were brought to a vote in the open assembly, using an Audience Response System (ARS). The strategic planning process was conducted to assess: Where are we at?; Where must we get to?; and What strategies are necessary to make progress on the prioritized action items? CONCLUSIONS: Three prioritized action items for each component of the solution and the percentage of the votes received are listed in the body of this proceeding.

Perceiving emotion in crowds: the role of dynamic body postures on the perception of emotion in crowded scenes.

Although the perception of emotion in individuals is an important social skill, very little is known about how emotion is determined from a crowd of individuals. We investigated the perception of emotion in scenes of crowds populated by dynamic characters each expressing an emotion. Facial expressions were masked in these characters and emotion was conveyed using body motion and posture only. We systematically varied the proportion of characters in each scene depicting one of two emotions and participants were required to categorise the overall emotion of the crowd. In Experiment 1, we found that the perception of emotions in a crowd is efficient even with relatively brief exposures of the crowd stimuli. Furthermore, the emotion of a crowd was generally determined by the relative proportions of characters conveying it, although we also found that some emotions dominated perception. In Experiment 2, we found that an increase in crowd size was not associated with a relative decrease in the efficiency with which the emotion was categorised. Our findings suggest that body motion is an important social cue in perceiving the emotion of crowds and have implications for our understanding of how we perceive social information from groups.

Effect of Object and Task Properties on Bimanual Transport.

The use of both hands simultaneously when manipulating objects is fairly commonplace, but it is not known what factors encourage people to use two hands as opposed to one during simple tasks such as transport. In particular, we are interested in three possible transport strategies: unimanual transport, handing off between hands, and symmetric bimanual transport. In this study, we investigate the effect of object size, weight, and starting and ending position (configuration) as well as the need to balance the object on the use of these three strategies in a bowl-moving task. We find that configuration and balance have a strong effect on choice of strategy, and size and weight have a weaker effect. Hand-offs are most often used when the task requires moving an object from left to right and vice versa, while the unimanual strategy was frequently used when passing front to back. The bimanual strategy is only weakly affected by configuration. The need to balance an object causes subjects to favor unimanual and bimanual strategies over the hand-off. In addition, an analysis of transport duration and body rotation suggests that strategy choice may be driven by the desire to minimize body rotation.

Influence of gamma and electron beam sterilization on the stability of a premixed injectable calcium phosphate cement for trauma indications.

Premixed calcium phosphate cements (CPC's) are becoming the material of choice for injectable cements as a result of their effective delivery to the target implantation site. For orthopaedic use, it is of vital importance that the attributes of these CPC's are not compromised by irradiation sterilization. Therefore, the aim of this study is to determine the influence of irradiation sterilization on a range of premixed CPC's, with an emphasis on improving product shelf life through the use of optimal packaging configurations and annealing steps. Electron spin resonance (ESR) confirmed the presence of free radicals in the inorganic phase of the CPC paste following irradiation. The inclusion of a 24-h annealing step was the only successful method in reducing the degree of free radical formation. Based on the results of injectability force testing, it was revealed that an annealing step greater than 24-h significantly altered the viscosity, however; at 24-h the key attributes of the CPC paste were minimally effected. Overall, it was established that vacuum packing the CPC paste, placing the contents into a foil pouch, gamma irradiating at the minimal dose required and using an annealing step of ≤ 24-h, has the potential to extend the shelf life of the cement.

Trending Paths: A New Semantic-Level Metric for Comparing Simulated and Real Crowd Data.

We propose a new semantic-level crowd evaluation metric in this paper. Crowd simulation has been an active and important area for several decades. However, only recently has there been an increased focus on evaluating the fidelity of the results with respect to real-world situations. The focus to date has been on analyzing the properties of low-level features such as pedestrian trajectories, or global features such as crowd densities. We propose the first approach based on finding semantic information represented by latent Path Patterns in both real and simulated data in order to analyze and compare them. Unsupervised clustering by non-parametric Bayesian inference is used to learn the patterns, which themselves provide a rich visualization of the crowd behavior. To this end, we present a new Stochastic Variational Dual Hierarchical Dirichlet Process ( SV-DHDP) model. The fidelity of the patterns is computed with respect to a reference, thus allowing the outputs of different algorithms to be compared with each other and/or with real data accordingly. Detailed evaluations and comparisons with existing metrics show that our method is a good alternative for comparing crowd data at a different level and also works with more types of data, holds fewer assumptions and is more robust to noise.

Unilateral neglect is not unilateral: evidence for additional neglect of extreme right space.

Six patients with visuospatial neglect following right hemisphere lesions were given three tasks that assessed performance in areas of space ranging from extreme left to extreme right. A line bisection task required the patients to detect and bisect lines of four different lengths at seven left-right spatial locations, a number report task required the patients to name 11 two-digit numbers in a left-right array, and a tiling task required patients to place small black tiles over the black squares of a grid that stretched from 65 degrees left to 65 degrees right. Performance was compared with that of 20 age-matched controls. The patients showed the characteristic signs of left-side neglect in left space, extending to the central midline. Performance was relatively normal in centre-right space but all 6 patients showed signs of neglect of extreme right space (60 degrees to the right of the midline and beyond). We propose that neglect is best characterised as a bilateral, asymmetrical compression of experienced space in which the constriction extends further from the left than from the right but nevertheless affects both sides of space.

Platelet-derived growth factor (PDGF) autocrine signaling regulates survival and mitogenic pathways in glioblastoma cells: evidence that the novel PDGF-C and PDGF-D ligands may play a role in the development of brain tumors.

Glioblastoma multiforme, the most common form of malignant brain tumor,is resistant to all forms of therapy and causes death within 9-12 months of diagnosis. Glioblastomas are known to contain numerous genetic and physiological alterations affecting cell survival and proliferation; one of the most common alterations being platelet-derived growth factor (PDGF) autocrine signaling characterized by coexpression of PDGF and its receptor. The PDGF family consists of four members, PDGF-A, -B, -C, and -D, that signal through the alpha and beta PDGF receptor (PDGFR) tyrosine kinases. Numerous studies have demonstrated expression of PDGF-A, PDGF-B, and the PDGFRs in gliomablastomas, but such studies have not been conducted for the newly identified PDGF-C and -D. Therefore, we examined the expression of all PDGF ligands and receptors in 11 glioma cell lines and 5 primary glioblastoma tumor tissues by quantitative reverse transcription-PCR. Expression of PDGF/PDGFR pairs that are known to functionally interact were identified in all of the samples. Interestingly, PDGF-C expression was ubiquitous in brain tumor cells and tissues but was very low or absent in normal adult and fetal brain. PDGF-D was expressed in 10 of 11 brain tumor cell lines and 3 of 5 primary brain tumor samples. As a strategy for blocking PDGFR signaling, CT52923, a potent selective small molecule piperazinyl quinazoline kinase inhibitor of the PDGFR, was identified. In model systems using NIH/3T3 cells, CT52923 blocked PDGF autocrine-mediated phosphorylation of PDGFR, Akt, and mitogen-activated protein kinase (MAPK), while having no effect on v-fms or V12-ras-mediated Akt or extracellular signal-regulated protein kinase (Erk) phosphorylation. More importantly, p.o. administration of CT52923 to nude mice caused a significant 61% reduction (P < 0.006) in tumor growth of NIH/3T3 cells transformed by PDGF, whereas tumor formation by cells expressing v-fms was unaffected. We next characterized PDGF autocrine signaling in five glioblastoma cell lines. In all of the cases, PDGF autocrine signaling was evident because treatment with 1-10 microM CT52923 inhibited PDGFR autophosphorylation when present at a detectable level and blocked downstream Akt and/or Erk phosphorylation. The functional significance of PDGF autocrine signaling in these cells was demonstrated by the fact that the CT52923 inhibited soft agar colony formation, and, when given p.o. to nude mice, it effectively reduced tumor formation by 44% (P < 0.0019) after s.c. injection of C6 glioblastoma cells. This study of glioblastoma cells and primary tissues is the first to implicate PDGF-C and -D in brain tumor formation and confirms the existence of autocrine signaling by PDGF-A and -B. More importantly, treatment with the PDGFR antagonist CT52923 inhibited survival and/or mitogenic pathways in all of the glioblastoma cell lines tested and prevented glioma formation in a nude mouse xenograft model. Together these findings demonstrate the potential therapeutic utility of this class of compounds for the treatment of glioblastoma.

Uncovering Barriers to Teaching Assistants (TAs) Implementing Inquiry Teaching: Inconsistent Facilitation Techniques, Student Resistance, and Reluctance to Share Control over Learning with Students.

Inquiry-based teaching approaches are increasingly being adopted in biology laboratories. Yet teaching assistants (TAs), often novice teachers, teach the majority of laboratory courses in US research universities. This study analyzed the perspectives of TAs and their students and used classroom observations to uncover challenges faced by TAs during their first year of inquiry-based teaching. Our study revealed three insights about barriers to effective inquiry teaching practices: 1) TAs lack sufficient facilitation skills; 2) TAs struggle to share control over learning with students as they reconcile long-standing teaching beliefs with newly learned approaches, consequently undermining their fledgling ability to use inquiry approaches; and 3) student evaluations reinforce teacher-centered behaviors as TAs receive positive feedback conflicting with inquiry approaches. We make recommendations, including changing instructional feedback to focus on learner-centered teaching practices. We urge TA mentors to engage TAs in discussions to uncover teaching beliefs underlying teaching choices and support TAs through targeted feedback and practice.