429 research outputs found
Development of a bedrest muscle stress apparatus
In attempting further to define the deleterious effects of spaceflight on the human body, measurement systems and techniques were devised to determine the loss of skeletal muscle strength and tone as a result of spaceflight exposure. In order to determine how the muscle degradation process progresses with time during nonuse, a system for measuring muscle stress during bedrest was developed. The Bedrest Muscle Stress Apparatus is configured to slip snugly over the foot board of a standard hospital bed. Data collected with this device correlated well with pre- and post-bedrest data collected with the original skeletal muscle stress apparatus
Characterization of gsp-Mediated Growth Hormone Excess in the Context of McCune-Albright Syndrome
McCune-Albright syndrome (MAS) is a disorder characterized by the triad of café-au-lait skin pigmentation, polyostotic fibrous dysplasia of bone, and hyperfunctioning endocrinopathies, including GH excess. The molecular etiology of the disease is postzygotic activating mutations of the GNAS1 gene product, Gsα. The term gsp oncogene has been assigned to these mutations due to their association with certain neoplasms. The aim of this study was to estimate the prevalence of GH excess in MAS, characterize the clinical and endocrine manifestations, and describe the response to treatment. Fifty-eight patients with MAS were screened, and 22 with stigmata of acromegaly and/or elevated GH or IGF-I underwent oral glucose tolerance testing. Twelve patients (21%) had GH excess, based on failure to suppress serum GH on oral glucose tolerance test, and underwent a TRH test, serial GH sampling from 2000-0800 h, and magnetic resonance imaging of the sella. We found that vision and hearing deficits were more common in patients with GH excess (4 of 12, 33%) than those without (2 of 56, 4%). Of interest, patients with a history of precocious puberty and GH excess who had reached skeletal maturity achieved normal adult height despite a history of early epiphyseal fusion. All 9 patients tested had an increase in serum GH after TRH, 11 of 12 (92%) had hyperprolactinemia, and all 8 tested had detectable or elevated nighttime GH levels. Pituitary adenoma was detected in 4 of 12 (33%) patients. All patients with elevated IGF-I levels were treated with cabergoline (7 patients), long-acting octreotide (LAO; 8 patients), or a combination of cabergoline and LAO (4 patients). In six of the seven patients (86%) treated with cabergoline, serum IGF-I decreased, but not to the normal range. In the eight patients treated with LAO alone, IGF-I decreased, and, in four, returned to the normal range. The remaining 4 patients were treated with a combination of cabergoline and LAO. For them, symptoms of GH excess diminished, and IGF-I decreased further, but did not enter the normal range. GH excess is common in MAS and results in a distinct clinical phenotype characterized by inappropriately normal stature, TRH responsiveness, prolactin cosecretion, small or absent pituitary tumors, a consistent but inadequate response to treatment with cabergoline, and an intermediate response to LAO
Microtubule Interaction Site of the Kinesin Motor
AbstractKinesin and myosin are motor proteins that share a common structural core and bind to microtubules and actin filaments, respectively. While the actomyosin interface has been well studied, the location of the microtubule-binding site on kinesin has not been identified. Using alanine-scanning mutagenesis, we have found that microtubule-interacting kinesin residues are located in three loops that cluster in a patch on the motor surface. The critical residues are primarily positively charged, which is consistent with a primarily electrostatic interaction with the negatively charged tubulin molecule. The core of the microtubule-binding interface resides in a highly conserved loop and helix (L12/α5) that corresponds topologically to the major actin-binding domain of myosin. Thus, kinesin and myosin have developed distinct polymer-binding domains in a similar region with respect to their common catalytic cores
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Contamination source review for Building E5032, Edgewood Area, Aberdeen Proving Ground, Maryland
This report by Argonne National Laboratory (ANL) documents results of a contamination source review of Building E5032 at the Aberdeen Proving Ground (APG) in Maryland. The review included a historical records search, physical inspection, photographic documentation, geophysical investigation, and review of available records regarding underground storage tanks associated with Building E5032. The field investigations were performed by ANL during 1994 and 1995. Building E5032 (APG designation), originally known as Building 99, is located at the northwest comer of the intersection of Hoadley Road and Magnolia Road in the Edgewood Area of APG. It was constructed during World War I as an incendiary bomb filling plant and in 1920s and 1930s maintained as a filling facility. During World War II the building was a pilot plant for the development of a dry white phosphorus filling process. Since then the building has been used for white phosphorus filling pilot studies. Most of the dry filling methods were developed in Building E5032 between 1965 and 1970. Other filling operations in Building E5032 have included mustard during the period shortly after World War II and triethyl aluminum (TEA) during the late 1960s and early 1970s. During the World War II period, the building was connected to the sanitary sewer system with one large and at least one small interior sump. There are also seven sumps adjacent to the exterior of the building: two on the west elevation, four near the four bays on the south elevation, and one at the northeast corner of the building. All of these sumps are connected with the chemical sewer system and received most, if not all, of the production operation wastewater. The discharge from this system was released into the east branch of Canal Creek; the discharge pipe was located southeast of Building E5032. There are no records indicating the use of Building E5032 after 1974, and it is assumed that the building has been out of service since that time
From START to FINISH : the influence of osmotic stress on the cell cycle
Peer reviewedPublisher PD
Failing to hash into supersingular isogeny graphs
An important open problem in supersingular isogeny-based cryptography is to
produce, without a trusted authority, concrete examples of "hard supersingular
curves" that is, equations for supersingular curves for which computing the
endomorphism ring is as difficult as it is for random supersingular curves. A
related open problem is to produce a hash function to the vertices of the
supersingular -isogeny graph which does not reveal the endomorphism ring,
or a path to a curve of known endomorphism ring. Such a hash function would
open up interesting cryptographic applications. In this paper, we document a
number of (thus far) failed attempts to solve this problem, in the hope that we
may spur further research, and shed light on the challenges and obstacles to
this endeavour. The mathematical approaches contained in this article include:
(i) iterative root-finding for the supersingular polynomial; (ii) gcd's of
specialized modular polynomials; (iii) using division polynomials to create
small systems of equations; (iv) taking random walks in the isogeny graph of
abelian surfaces; and (v) using quantum random walks.Comment: 33 pages, 7 figure
The prognostic significance of Cdc6 and Cdt1 in breast cancer
DNA replication is a critical step in cell proliferation. Overexpression of MCM2-7 genes correlated with poor prognosis in breast cancer patients. However, the roles of Cdc6 and Cdt1, which work with MCMs to regulate DNA replication, in breast cancers are largely unknown. In the present study, we have shown that the expression levels of Cdc6 and Cdt1 were both significantly correlated with an increasing number of MCM2-7 genes overexpression. Both Cdc6 and Cdt1, when expressed in a high level, alone or in combination, were significantly associated with poorer survival in the breast cancer patient cohort (n = 1441). In line with this finding, the expression of Cdc6 and Cdt1 was upregulated in breast cancer cells compared to normal breast epithelial cells. Expression of Cdc6 and Cdt1 was significantly higher in ER negative breast cancer, and was suppressed when ER signalling was inhibited either by tamoxifen in vitro or letrozole in human subjects. Importantly, breast cancer patients who responded to letrozole expressed significantly lower Cdc6 than those patients who did not respond. Our results suggest that Cdc6 is a potential prognostic marker and therapeutic target in breast cancer patients
Building Partnerships to Address Social and Technological Challenges to Enhance Farm Profitability and Improve Water Quality Through Better Grassland Management
With 2.1 million acres of pastureland and 1.25 million acres of hay land in Virginia, the rural Virginia landscape is predominately grassland. These lands form the base of the 75 per cow by extending their grazing season. The same phenomenon applies to other types of grazing livestock. If ten percent of the livestock producers in the state adopted better grazing management to extend their grazing season by 60 days, profitability is expected for Virginia grazing livestock producers by over $5 million per year. Practices such as rotational grazing and stream exclusion are directly tied to National and State goals to improve water quality in the Chesapeake Bay. Virginia’s Phase III WIP (Chesapeake Bay Watershed Improvement Plan) seeks the exclusion of livestock from all perennial streams and achieving good rotational grazing practices on 347,000 acres of pasture. A number of agencies and private sector groups have been providing cost share and technical guidance to incentivize livestock stream exclusion and the installation of pasture management infrastructure. Installation is only part of the challenge. Farmers also need to be taught how to how to manage the system in a profitable manner and have been slow to adopt good pasture management practices. Preliminary data show that 87% of Virginia’s cow-calf producers manage their grasslands using traditional methods. Only six percent have extended their grazing season beyond 265 days
Standard values and relationship-specific validity of the Bielefeld Relationship Expectations Questionnaire (BFPE)
<p>Abstract</p> <p>Background</p> <p>The Bielefeld Partnership Expectations Questionnaire (BFPE) is a tool to assess attachment in the romantic relationships of adults. The attachment styles are operationalized as configuration patterns of scale scores. While convergent validity has already been investigated, discriminant validity is still lacking confirmation.</p> <p>Methods</p> <p>The present sample (n = 1509) is representative for the German population aged 18 to 50. The mean age was 34.6 years. Most of the participants lived in a relationship (77.3 %). Discriminant validity was analyzed using a marital quality questionnaire (PFB), a social support questionnaire (F-Soz-U K-14), and a life satisfaction questionnaire (FLZ).</p> <p>Results</p> <p>All the BFPE scales have a satisfying internal consistency between r = .79 and .86. Those individuals who showed a secure pattern, i.e. increased "Readiness for Self-Disclosure" and "Conscious Need for Care" as well as reduced "Fear of Rejection" experienced their partner as socially supportive, reported higher marital quality in all of its facets, and were more satisfied within the life-domains "family/children" and "relationship/sexuality". Standard values for each scale are presented.</p> <p>Conclusions</p> <p>The BFPE has repeatedly been verified as a short, reliable, and valid instrument applicable to research practice with healthy individuals as well as within clinical contexts.</p
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