18,085 research outputs found
Topography and mechanical properties of single molecules of type I collagen using atomic force microscopy
Although the mechanical behavior of tendon and bone has been studied for decades, there is still relatively little understanding of the molecular basis for their specific properties. Thus, despite consisting structurally of the same type I collagen, bones and tendons have evolved to fulfill quite different functions in living organisms. In an attempt to understand the links between the mechanical properties of these collageneous structures at the macro- and nanoscale, we studied trimeric type I tropocollagen molecules by atomic force microscopy, both topologically and by force spectroscopy. High-resolution imaging demonstrated a mean (± SD) contour length of (287 ± 35) nm and height of (0.21 ± 0.03) nm. Submolecular features, namely the coil-pitch of the molecule, were also observed, appearing as a repeat pattern along the length of the molecule, with a length of ~8 nm that is comparable to the theoretical value. Using force spectroscopy, we established the stretching pattern of the molecule, where both the mechanical response of the molecule and pull-off peak are convoluted in a single feature. By interpreting this response with a wormlike chain model, we extracted the value of the effective contour length of the molecule at (202 ± 5) nm. This value was smaller than that given by direct measurement, suggesting that the entire molecule was not being stretched during the force measurements; this is likely to be related to the absence of covalent binding between probe, sample, and substrate in our experimental procedure
The identification and correction of channel-to-channel phase differences within a data processing system
Data processing hardware was tested in order to determine the sources of channel time delay differences and mathematically characterize the differences. A procedure developed to detect and correct these delay differences was subjected to test data in order to verify its capability. Test results are presented
Method of making impurity-type semiconductor electrical contacts Patent
Fabrication of sintered impurity semiconductor brushes for electrical energy transfe
Improved molybdenum disulfide-silver motor brushes have extended life
Motor brushes of proper quantities of molybdenum disulfide and copper or silver are manufactured by sintering techniques. Graphite molds are used. These brushes operate satisfactorily for long periods in normal atmosphere or in a high-vacuum environment
A self-study course in FORTRAN programming. Volume 2 - Workbook
Self study workbook for course in FORTRAN programming - Vol.
Crop identification using ERTS imagery
Digital analysis of August 15 ERTS-I imagery for southeastern South Dakota was performed to determine the feasibility of conducting crop surveys from satellites. Selected areas of bands 4, 5, 6, and 7 positive transparencies were converted to digital form utilizing Signal Analysis and Dissemination Equipment (SADE). The optical transmission values were printed out in a spatial format. Visual analysis of the printouts indicated that cultivated areas were readily distinguished from non-cultivated areas in all four bands. Bare soil was easily recognized in all four bands. Corn and soybeans, the two major crops in the area, were treated as separate classes rather than as a single class called row crops. Bands 6 and 7 provided good results in distinguishing between corn and soybeans
A self-study course in FORTRAN programming. Volume 1 - Textbook
Self study textbook for course in FORTRAN programming - Vol.
FORTRAN programming - A self-taught course
Comprehensive programming course begins with numerical systems and basic concepts, proceeds systematically through FORTRAN language elements, and concludes with discussion of programming techniques. Course is suitable either for individual study or for group study on informal basis
Community-level characteristics of high infant mortality: A tool to identify at-risk communities
Infant mortality (IM) rate is a key indicator of population health and has been gradually improving in the United States. However, it is still a public health problem among minority and low-income communities. Maternal factors explain some of the variation, but community-level factors may also be a contributor. This study examines measures to identify a set of indicators that explain variations in IM at the community-level. Data for 77 communities in a city were obtained from local health databases. We used multivariable linear regression models to examine the strength of the association between IM and maternal, population, community wealth, and social capital characteristics. Community-level IM rates ranged from 2.1 – 25.6 deaths per 1,000 live births in 2000-2002. The final model explained 75% of the variation in IM rates at the community-level (R2=0.75). The model included a high percentage of low birth weight babies, a decline in mothers who began prenatal care in the second trimester, an increase in the percentage of Hispanics, increased unemployment rates, an increase in the percentage of veterans, an increased rate of foreign-born residents, and smaller average family sizes. Social capital variables, homicide rate and vacant housing, were also significant in the final model. Identifying communities at risk for high IM rates is imperative to improve maternal and child health outcomes because of shortages in public health resources. The development of a parsimonious set of community-level indicators can assist public health practitioners in targeting their resources to prevent infant mortality in high-risk communities
Food for Thought: Genetically Modified Seeds as De Facto Standard Essential Patents
For several years, courts have been improperly calculating damages in cases involving the unlicensed use of genetically-modified (GM) seed technology. In particular, when courts determine patent damages based on the hypothetical negotiation method, they err in exaggerating these damages to a point where no rational negotiator would agree. In response, we propose a limited affirmative defense of an implied license due to the patent’s status as a de facto standard essential patent. To be classified as a de facto standard essential patent, the farmer must prove three elements that reflect the peculiarities of GM seeds used in farming: (1) dominance, (2) impracticability, and (3) necessary to fulfill a basic need. Based on the approaches used by courts and standard setting organizations in licensing standard essential patents in technological fields such as cell phones and software, designation of some GM seeds as standard essential patents allows the courts to imply a license from patentees to farmers on reasonable and non-discriminatory (RAND) terms. Doing so shifts the case from a tort-based patent infringement suit to a breach of contract dispute and alters the damages regime from one based in compensation, deterrence, and punishment (a tort approach) to one based solely in compensation (a contractual approach). As a result of this novel proposal, the damages calculations in these suits return to economic reality
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