1,094 research outputs found
Microspine Gripping Mechanism for Asteroid Capture
This paper details the development and early testing of a compliant suspension for a microspine gripper device for asteroid capture or micro-gravity percussive drilling. The microspine gripper architecture is reviewed, and a proposed microspine suspension design is presented and discussed. Prototyping methods are discussed, as well as testing methods and results. A path forward is identified from the results of the testing completed thus far. Key findings include: the microspine concept has been established as a valid architecture and the compliant suspension exhibits the desired stiffness characteristics for good gripping behavior. These developments will aid in developing the capability to grasp irregularly shaped boulders in micro-gravity
The initiator methionine tRNA drives secretion of type II collagen from stromal fibroblasts to promote tumor growth and angiogenesis
Summary:
Expression of the initiator methionine tRNA (tRNAi
Met)
is deregulated in cancer. Despite this fact, it is not
currently known how tRNAi
Met expression levels influence
tumor progression. We have found that tRNAi
Met
expression is increased in carcinoma-associated
fibroblasts, implicating deregulated expression of
tRNAi
Met in the tumor stroma as a possible contributor
to tumor progression. To investigate how elevated
stromal tRNAi
Met contributes to tumor progression,
we generated a mouse expressing additional copies
of the tRNAi
Met gene (2+tRNAi
Met mouse). Growth
and vascularization of subcutaneous tumor allografts
was enhanced in 2+tRNAi
Met mice compared with
wild-type littermate controls. Extracellular matrix
(ECM) deposited by fibroblasts from 2+tRNAi
Met
mice supported enhanced endothelial cell and fibroblast
migration. SILAC mass spectrometry indicated
that elevated expression of tRNAi
Met significantly
increased synthesis and secretion of certain types of
collagen, in particular type II collagen. Suppression
of type II collagen opposed the ability of tRNAi
Metoverexpressing
fibroblasts to deposit pro-migratory
ECM. We used the prolyl hydroxylase inhibitor ethyl-
3,4-dihydroxybenzoate (DHB) to determine whether
collagen synthesis contributes to the tRNAi
Met-driven
pro-tumorigenic stroma in vivo. DHB had no effect
on the growth of syngeneic allografts in wild-type
mice but opposed the ability of 2+tRNAi
Met mice to
support increased angiogenesis and tumor growth.
Finally, collagen II expression predicts poor prognosis
in high-grade serous ovarian carcinoma. Taken
together, these data indicate that increased tRNAi
Met
levels contribute to tumor progression by enhancing
the ability of stromal fibroblasts to synthesize and
secrete a type II collagen-rich ECM that supports
endothelial cell migration and angiogenesis
Improving rigid fiberoptic intubation: a comparison of the Bonfils Intubating Fiberscopeā¢ with a novel modification
<p>Abstract</p> <p>Background</p> <p>The Bonfils intubating fiberscope has a limited upward tip angle of 40Ā° and requires retromolar entry into the hypopharynx. These factors may make its use less desirable when managing the difficult airway because most anesthesia providers are well versed in midline oral intubation rather than the lateral retromolar approach. The <it>Center for Advanced Technology and Telemedicine </it>at the University of Nebraska Medical Center has developed a novel fiberscope with a more anterior 60Ā° curve to allow for easier midline insertion and intubation. The objective of this work was to evaluate the novel fiberscope, in comparison to the Bonfils intubating fiberscope, in terms of use and function in difficult airway intubation.</p> <p>Methods</p> <p>Twenty-two anesthesia providers participated in simulated intubations of a difficult airway mannequin to compare the Bonfils intubating fiberscope with the novel curved Boedeker intubating fiberscope. The intubations were assessed based upon the following variables: recorded Cormack Lehane airway scores, requests for cricoid pressure, time to intubation, number of intubation attempts and success or failure of the procedure.</p> <p>Results</p> <p>Participants using the Bonfils fiberscope recorded an average Cormack Lehane (CL) airway score of 1.67 Ā± 1.02 (median = 1); with the novel fiberscope, the recorded average airway grade improved to 1.18 Ā± 0.50 (median = 1). The difference in airway scores was not statistically significant (p = 0.34; Fishers Exact Test comparing CL grades 1&2 vs. 3&4). There was, however, a statistically significant difference in intubation success rates between the two devices. With the Bonfils fiberscope, 68% (15/22) of participants were successful in intubation compared to a 100% success rate in intubation with the novel fiberscope (22/22) (p = 0.008). After the intubation trial, the majority of participants (95%) indicated a preference for the novel fiberscope (n = 20).</p> <p>Conclusions</p> <p>With this data, we can infer that the novel fiberscope curvature appears to improve or maintain the quality of an intubation attempt (airway score, cricoid pressure requirement, intubation time, number of attempts, placement success). The data indicate that the novel fiberscope offers a superior intubation experience to currently available best practices. The instrument was well received and would be welcomed by most study participants should the device become clinically available in the future.</p
Lessons from agriculture for the sustainable management of malaria vectors.
Willem Takken and colleagues argue for the expansion of insecticide monotherapy in malaria control by taking lessons from agriculture and including more sustainable integrated vector management strategies
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