481 research outputs found

    Motility of triton-demembranated sea urchin sperm flagella during digestion by trypsin

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    The survival curves for a population of reactivated spermatozoa exposed to digestion by trypsin indicate that a large number of trypsin-sensitive targets must be digested before the flagellum disintegrates. Changes in flagellar movement during trypsin digestion can be very small, especially when the spermatozoa are reactivated at 0.25 M KCl. They are not the changes which would be expected if elastic resistance of the trypsin-sensitive structures responsible for maintaining the integrity of the axoneme is a significant determinant of flagellar bend amplitude. By carrying out trypsin digestion under a variety of conditions, at least six distinct effects of trypsin digestion on parameters of flagellar movement have been detected. These include a gradual increase in the rate of sliding between tubules, gradual and abrupt changes in beat frequency accompanied by reciprocal decreases in bend angle, changes in the symmetry and planarity of bending, and selective interference with mechanisms for bend initiation and bend propagation

    Shock tube measurements of growth constants in the branched chain formaldehyde-carbon monoxide-oxygen system

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    Exponential free radical growth constants were measured for formaldehyde carbon monoxide-oxygen systems by monitoring the growth of oxygen atom concentration as manifested by CO flame band emission. Data were obtained over the temperature range of 1200 to 2000 K. The data were analyzed using a formaldehyde oxidation mechanism involving 12 elementary reaction steps. The computed growth constants are roughly in accord with experimental values, but are much more temperature dependent. The data was also analyzed assuming formaldehyde is rapidly decomposed to carbon monoxide and hydrogen. Growth constants computed for the resulting carbon monoxide hydrogen oxygen mixtures have a temperature dependence similar to experiments; however, for most mixtures, the computed growth constants were larger than experimental values

    Information integration and management through the design and construction phases of a project life cycle

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    Information management is a key aspect of successful construction projects. Having inaccurate measurements and conflicting data can lead to costly mistakes, and vague quantities can ruin estimates and schedules. Building information modeling (BIM) augments a 3D model with a wide variety of information, which reduces many sources of error and can detect conflicts before they occur. Because new technology is often more complex, it can be difficult to effectively integrate it with existing business practices. In this paper, we will answer two questions: How can BIM add value to construction projects? and What lessons can be learned from other companies that use BIM or other similar technology? Previous research focused on the technology as if it were simply a tool, observing problems that occurred while integrating new technology into existing practices. Our research instead looks at the flow of information through a company and its network, seeing all the actors as part of an ecosystem. Building upon this idea, we proposed the metaphor of an information supply chain to illustrate how BIM can add value to a construction project. This paper then concludes with two case studies. The first case study illustrates a failure in the flow of information that could have prevented by using BIM. The second case study profiles a leading design firm that has used BIM products for many years and shows the real benefits of using this program

    Shock tube measurements of growth constants in the branched-chain ethane-carbon monoxide-oxygen system

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    Exponential free radical growth constants have been measured for ethane carbon monoxide oxygen mixtures by monitoring the growth of oxygen atom concentration as manifested by CO flame band emission. Data were obtained over the temperature range of 1200 to 1700 K. The data were analyzed using an ethane oxidation mechanism involving seven elementary reaction steps. Calculated growth constants were close to experimental values at lower temperatures, up to about 1400 K, but at higher temperatures computed growth constants were considerably smaller than experiment. In attempts to explain these results additional branching reactions were added to the mechanism. However, these additional reactions did not appreciably change calculated growth constants

    Technology-assisted stroke rehabilitation in Mexico: a pilot randomized trial comparing traditional therapy to circuit training in a Robot/technology-assisted therapy gym

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    Background Stroke rehabilitation in low- and middle-income countries, such as Mexico, is often hampered by lack of clinical resources and funding. To provide a cost-effective solution for comprehensive post-stroke rehabilitation that can alleviate the need for one-on-one physical or occupational therapy, in lower and upper extremities, we proposed and implemented a technology-assisted rehabilitation gymnasium in Chihuahua, Mexico. The Gymnasium for Robotic Rehabilitation (Robot Gym) consisted of low- and high-tech systems for upper and lower limb rehabilitation. Our hypothesis is that the Robot Gym can provide a cost- and labor-efficient alternative for post-stroke rehabilitation, while being more or as effective as traditional physical and occupational therapy approaches. Methods A typical group of stroke patients was randomly allocated to an intervention (n = 10) or a control group (n = 10). The intervention group received rehabilitation using the devices in the Robot Gym, whereas the control group (n = 10) received time-matched standard care. All of the study subjects were subjected to 24 two-hour therapy sessions over a period of 6 to 8 weeks. Several clinical assessments tests for upper and lower extremities were used to evaluate motor function pre- and post-intervention. A cost analysis was done to compare the cost effectiveness for both therapies. Results No significant differences were observed when comparing the results of the pre-intervention Mini-mental, Brunnstrom Test, and Geriatric Depression Scale Test, showing that both groups were functionally similar prior to the intervention. Although, both training groups were functionally equivalent, they had a significant age difference. The results of all of the upper extremity tests showed an improvement in function in both groups with no statistically significant differences between the groups. The Fugl-Meyer and the 10 Meters Walk lower extremity tests showed greater improvement in the intervention group compared to the control group. On the Time Up and Go Test, no statistically significant differences were observed pre- and post-intervention when comparing the control and the intervention groups. For the 6 Minute Walk Test, both groups presented a statistically significant difference pre- and post-intervention, showing progress in their performance. The robot gym therapy was more cost-effective than the traditional one-to-one therapy used during this study in that it enabled therapist to train up to 1.5 to 6 times more patients for the approximately same cost in the long term. Conclusions The results of this study showed that the patients that received therapy using the Robot Gym had enhanced functionality in the upper extremity tests similar to patients in the control group. In the lower extremity tests, the intervention patients showed more improvement than those subjected to traditional therapy. These results support that the Robot Gym can be as effective as traditional therapy for stroke patients, presenting a more cost- and labor-efficient option for countries with scarce clinical resources and funding. Trial registration ISRCTN98578807

    Proteomic analysis of the Plasmodium male gamete reveals the key role for glycolysis in flagellar motility.

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    BACKGROUND: Gametogenesis and fertilization play crucial roles in malaria transmission. While male gametes are thought to be amongst the simplest eukaryotic cells and are proven targets of transmission blocking immunity, little is known about their molecular organization. For example, the pathway of energy metabolism that power motility, a feature that facilitates gamete encounter and fertilization, is unknown. METHODS: Plasmodium berghei microgametes were purified and analysed by whole-cell proteomic analysis for the first time. Data are available via ProteomeXchange with identifier PXD001163. RESULTS: 615 proteins were recovered, they included all male gamete proteins described thus far. Amongst them were the 11 enzymes of the glycolytic pathway. The hexose transporter was localized to the gamete plasma membrane and it was shown that microgamete motility can be suppressed effectively by inhibitors of this transporter and of the glycolytic pathway. CONCLUSIONS: This study describes the first whole-cell proteomic analysis of the malaria male gamete. It identifies glycolysis as the likely exclusive source of energy for flagellar beat, and provides new insights in original features of Plasmodium flagellar organization

    Remembering Our Past: Teaching the History of Anatomy at Indiana University

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    Most students pursuing careers in anatomy or related disciplines have a limited understanding of how, over the centuries, the intricate structure of the human body came to be known. To provide students with the relevant historical perspective, we developed a team-taught survey course in the history of anatomical sciences—including gross anatomy, histology, neuroanatomy, and embryology—from antiquity to the present. Taught entirely via Zoom during the Spring semester of 2021, History of Anatomy (2 semester hours credit) met once per week for approximately 2 hours. Enrollment consisted of 5 undergraduate students majoring in Biology (2), Human Biology (2), or Anthropology (1), as well as 3 graduate students pursuing either a master’s degree in Clinical Anatomy (1) or a Ph.D. in Anatomy Education (2). Three of the students had no prior coursework in anatomy. Through assigned readings, lectures, and discussions, the class explored the work of the great anatomists and their discoveries. A particular emphasis was placed on the evolution of anatomy as a discipline and the cultural influences, scientific controversies, and ethical dilemmas facing its practitioners. Syllabus topics included critical appraisals of the role of gender, race, and ethnicity in anatomical discovery. A key feature of the course was the opportunity for students to engage in robust discussions about such controversial issues as: Eurocentric biases in our understanding of human anatomy and the untold story of Muslim contributions to anatomical knowledge well before Vesalius; Competing claims of priority for who “discovered” the pulmonary circulation; The underappreciated role of women in the history of anatomy and medicine; The ethical quandary of teaching anatomy from archival fetal specimens obtained before the era of informed consent; Accusations that famed anatomist William Hunter used the bodies of murdered pregnant women to create his anatomical atlas of the gravid uterus; Complicity of Eduard Pernkopf and other Nazi-era anatomists in the unethical use of executed victims to obtain images for a renowned anatomical atlas. All students were assessed through weekly homework (written responses to study questions), a mid-term writing assignment, and a term paper about an historical topic of the student’s choosing. Graduate students had the additional requirement of a class presentation about their term paper topic. The end-of-course evaluation suggested that the course was well-received by the students (mean Likert score = 4.63 on a 5-point scale; n = 6). Based on this positive reception, we plan to offer History of Anatomy again on a recurring basis. We believe that by knowing our history, both the good and the bad, future practitioners of anatomy and related disciplines will be less likely to perpetuate the biases and ethical transgressions of earlier eras.American Association for Anatomy Spring Meetin
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