814 research outputs found
Architecture for Control of the K9 Rover
Software featuring a multilevel architecture is used to control the hardware on the K9 Rover, which is a mobile robot used in research on robots for scientific exploration and autonomous operation in general. The software consists of five types of modules: Device Drivers - These modules, at the lowest level of the architecture, directly control motors, cameras, data buses, and other hardware devices. Resource Managers - Each of these modules controls several device drivers. Resource managers can be commanded by either a remote operator or the pilot or conditional-executive modules described below. Behaviors and Data Processors - These modules perform computations for such functions as planning paths, avoiding obstacles, visual tracking, and stereoscopy. These modules can be commanded only by the pilot. Pilot - The pilot receives a possibly complex command from the remote operator or the conditional executive, then decomposes the command into (1) more-specific commands to the resource managers and (2) requests for information from the behaviors and data processors. Conditional Executive - This highest-level module interprets a command plan sent by the remote operator, determines whether resources required for execution of the plan are available, monitors execution, and, if necessary, selects an alternate branch of the plan
School-Based Relationships Among Children with or at Risk for Emotional and Behavioral Disorders
We investigated the influence of a teacherâs perceived emotional state (e.g., feeling emotionally exhausted; feeling accomplished) on the association between parent-teacher relationships and teacher-child conflict among young children. We used pretest data from a pilot study examining the efficacy of a socio-emotional learning intervention for children with or at risk for emotional or behavioral disorders (EBD). Twenty-six teachers and 45 children (Mean age= 7.46 years; SD = 1.21) participated in the intervention. Teachers rated their relationships with children and their parents using the Parent-Teacher Relationship Scale and Student-Teacher Relationship Scale. Multilevel models showed that teachers with a higher sense of personal accomplishment evidenced a negative association between parent-teacher relationships and teacher-child conflict. However, for teachers who felt emotionally exhausted or those who had a lower sense of personal achievement, the association between parent-teacher relationships and teacher-child conflict either remained unchanged or was positive. We conclude by discussing findings in relation to the importance of increasing teacher efficacy, reducing teacher burnout, and strengthening parent-teacher relationships in schools to improve teacher-child relationships and childrenâs psychosocial outcomes
Mitochondrial Dysfunction is Evident in Lewis Lung Carcinoma-Induced Muscle Wasting
Cancer cachexia is a paraneoplastic syndrome associated with adverse prognosis and shortened survival. The defining feature of cachexia is extensive muscle atrophy leading to progressive functional impairments. The molecular mechanisms responsible for the rapid muscle wasting are not fully elucidated. Based on emerging evidence, we developed the hypothesis cachectic muscle wasting is caused by mitochondrial dysfunction increasing reactive oxygen species production leading to global oxidative stress. To test this hypothesis we utilized the well-established Lewis-Lung Carcinoma (LLC) model of cancer cachexia. The time-course study consisted of one, two, three and four week LLC tumor bearing mice and age-matched four week saline (PBS) control (Ctrl) mice. Tumors were implanted into the hind flank at 1X106 cells in 100 ”L PBS. The plantaris was weighed for wet mass then teased into small fiber bundles and permeabilized for the quantification of mitochondrial function. Mitochondrial dysfunction was classified by a decrease in the respiratory control ratio (RCR), which is the ratio of state 3 (maximal ADP stimulated respiration) to state 4 (oligomycin-induced leak respiration). Muscle mass progressively declined over the time-course, reaching significance at 4 weeks (Ctrl vs 4-week, p\u3c0.05). Mitochondrial function was not different among groups, however individual a priori comparison between groups revealed that 4wk cancer animals exhibited marked mitochondrial dysfunction compared to all other groups (p\u3c0.05). These data demonstrate that late stage cancer-induced muscle wasting is associated with significant mitochondrial dysfunction
Mitochondrial Dysfunction in Diaphragm Muscle Precedes the Cachectic Phenotype in LLC Tumor-Bearing Mice.
The defining feature of cancer cachexia is extensive weight loss and skeletal muscle atrophy. It is clinically important because cachexia reduces patient survival, results in functional impairment, and is estimated to be directly responsible for 20-40% of cancer deaths. Unfortunately, no clinical therapy exists and therefore, it is important to understand the molecular mechanisms responsible for rapid muscle wasting. Compared to limb muscles, the diaphragm is relatively understudied in cancer cachexia, but is likely to be adversely affected because cachexia is a systemic disease. Wasting of the primary inspiratory muscle may result in difficulty breathing and inability to adjust minute ventilation in response to a respiratory challenge. Based on emerging evidence, it is clear that oxidative stress is present in cachexia-induced wasting of the diaphragm; PURPOSE: we developed the hypothesis that mitochondrial dysfunction in the diaphragm precedes cachexia. METHODS: 1X106 Lewis Lung Carcinoma cells (LLC) or Phosphate-Buffered Saline (PBS, control) were implanted to the hind-flank of C57BL6/J mice at 8 wks of age. Tumors were allowed to develop for 1, 2, 3, or 4 wks. At designated time points diaphragms were collected and mitochondrial function was assessed by respiration and ROS production. RESULTS: Cancer cachexia was evident only at the 4 wk time point demonstrated by decrease in body mass and muscle atrophy in several limb muscles. Mitochondrial respiration, assessed by respiratory control ratio (state3/state 4 respiration), was significantly lower at 1 wk (pCONCLUSIONS:The molecular events that lead to muscle atrophy in cancer cachexia are unknown. We demonstrate that two hallmarks of mitochondrial dysfunction, altered respiration and ROS production, occur in the diaphragm well before the cancer cachexia phenotype is evident in the LLC model. These data suggest that the mitochondria are likely a suitable target to treat or prevent cancer cachexia-induced muscle wasting in the diaphragm
Fractional Synthetic Rate and Markers of Protein Turnover are Altered in the Diaphragms of Cachectic Mice
Cancer cachexia, a wasting syndrome characterized by rapid skeletal muscle wasting and fat loss, directly accounts for up to 20-40% of cancer-related deaths. All muscles, including respiratory muscles, are susceptible to atrophy because cancer cachexia is a systemic disease. Atrophy of the primary breathing muscle, the diaphragm, can lead to respiratory distress, which is commonly associated with a cachectic phenotype. Indeed, the diaphragm is more susceptible to atrophy in certain conditions, but little is known about the effects of cancer-cachexia on protein turnover in the diaphragm. Therefore, investigations into the alterations in protein turnover could provide insight to the molecular events and provide valuable information in the search for therapeutic targets. PURPOSE: The purpose of this study was to describe changes in diaphragmatic protein synthesis and molecular markers of synthesis and degradation during the progression of cancer cachexia. METHODS: C57BL6/J mice (8 wks old) were implanted with 1X106 Lewis Lung Carcinoma cells (LLC) or Phosphate-Buffered Saline (PBS, control). Tumors developed over a 1-4 wk time course and diaphragms were harvested at each time point (1, 2, 3, or 4 wks). Fractional synthetic rates (FSR) were determined using deuterium incorporation into muscle. Selected markers of protein synthesis and degradation pathways were analyzed by immunoblot analysis. One-Way ANOVA was used for statistical analyses, with significance set at pRESULTS: FSR trended downward over time, but did not reach significance. Similar to FSR, anabolic signaling markers (4EBP-1, ERK1/2, Deptor) did not demonstrate significant differences. p62, an autophagic degradation marker, was significantly less than PBS in 3 wk diaphragms (
Giant GalĂĄpagos tortoises; molecular genetic analyses identify a trans-island hybrid in a repatriation program of an endangered taxon
BACKGROUND: Giant Galåpagos tortoises on the island of Española have been the focus of an intensive captive breeding-repatriation programme for over 35 years that saved the taxon from extinction. However, analysis of 118 samples from released individuals indicated that the bias sex ratio and large variance in reproductive success among the 15 breeders has severely reduced the effective population size (N(e)). RESULTS: We report here that an analysis of an additional 473 captive-bred tortoises released back to the island reveals an individual (E1465) that exhibits nuclear microsatellite alleles not found in any of the 15 breeders. Statistical analyses incorporating genotypes of 304 field-sampled individuals from all populations on the major islands indicate that E1465 is most probably a hybrid between an Española female tortoise and a male from the island of Pinzón, likely present on Española due to human transport. CONCLUSION: Removal of E1465 as well as its father and possible (half-)siblings is warranted to prevent further contamination within this taxon of particular conservation significance. Despite this detected single contamination, it is highly noteworthy to emphasize the success of this repatriation program conducted over nearly 40 years and involving release of over 2000 captive-bred tortoises that now reproduce in situ. The incorporation of molecular genetic analysis of the program is providing guidance that will aid in monitoring the genetic integrity of this ambitious effort to restore a unique linage of a spectacular animal
Potential effects of ionizing radiation on the evidentiary value of DNA, latent fingerprints, hair, and fibers: A comprehensive review and new results
An extensive literature review and new post-irradiation experimental results are presented of genotyping blood stains and hair, and physical examinations of latent fingerprints, hairs, and fibers. Results indicate that successful development of nuclear short tandem repeat (STR) and mitochondrial DNA sequence profiles from human blood and hair evidence is possibleâup to a pointâfollowing exposure to gamma, neutron, beta, and alpha radiation at several levels that would most likely be present at this type of crime scene (i.e., a âdirty bomb,â etc.). Commencing at gamma radiation levels between 90 and 900 kGy, DNA analysis using conventional DNA techniques was unsuccessful. In general, irradiation negatively affected the quality of latent fingerprints. All four radiation types degraded most fingerprint samples at all doses; nevertheless, many fingerprints remained of value for potential use in comparison. Although variable from one hair to another, microscopic changes observed for all types and levels of irradiation could potentially result in false exclusions. Negligible microscopic changes were observed in papers and fibers (used as substrates for fingerprints and bloodstains) up to 90 kGy gamma, but fluorescence of fibers began to change above that dose. Paper and fibers, as well as plastic evidence enclosures, became extremely brittle leading to breakage after a gamma dose of 900 kGy
Disuse Atrophy Occurs Without a Change in Mitochondrial Respiratory Control Ratio During Hindlimb Unloading in Mice
Skeletal muscle atrophy commonly occurs during prolonged periods of inactivity, however, the precise mechanisms that cause muscle atrophy have yet to be determined. Specifically, a controversy exists on whether mitochondrial dysfunction is a cause or consequence of disuse muscle atrophy. PURPOSE: The purpose of this study was to determine if a change in the respiratory control ratio, which is a ratio of maximal O2 respiration to leak respiration, could be detected prior to muscle atrophy in a time-course study in mice. METHODS: Disuse atrophy was induced using hindlimb unloading (HU) in adult, C57BL/6J male mice for 0 (control), 1, 2, 3, or 7 days (n=~6-8/group). Following completion, gastrocnemius and soleus muscles were weighed and assessed for mitochondrial function in permeabilized muscle fibers. Here, we define mitochondrial function as the respiratory control ratio (RCR) determined by maximal ADP stimulated respiration (State 3) divided by leak or ATP synthase inhibited (state 4) respiration. A one-way ANOVA was used to determine differences between means. When significant F ratios were found, a Tukey post-hoc was used to compare differences between means. Values presented are mean ± standard error RESULTS: In both the gastrocnemius and soleus, muscle mass was not significantly different from control at day 1, but was significantly lower at 2, 3, and 7-day timepoints. In contrast, there was no significant difference in RCR in gastrocnemius (control 3.11±0.20, 1 day 2.96±0.60, 2 day 3.07±0.31, 3 day 3.08±0.25, 7 day 3.41± .29) or soleus (control 2.33±0.33, 1 day 2.77±0.33, 2 day 3.03±0.51, 3 day 2.93±0.30, 7 day 2.78±0.48). CONCLUSION: It is well established that HU causes rapid muscle atrophy. These data support mitochondrial RCR does decrease before muscle atrophy in either gastrocnemius or soleus muscle, and therefore may not be a primary cause of HU-induced muscle atrophy in mice
âWhat if There's Something Wrong with Her?ââHow Biomedical Technologies Contribute to Epistemic Injustice in Healthcare
While there is a steadily growing literature on epistemic injustice in healthcare, there are few discussions of the role that biomedical technologies play in harming patients in their capacity as knowers. Through an analysis of newborn and pediatric genetic and genomic sequencing technologies (GSTs), I argue that biomedical technologies can lead to epistemic injustice through two primary pathways: epistemic capture and value partitioning. I close by discussing the larger ethical and political context of critical analyses of GSTs and their broader implications for just and equitable healthcare delivery
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