1,486 research outputs found
Nonlinear cascades of surface oceanic geostrophic kinetic energy in the frequency domain
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111877/1/jpo_frequencycascades_2012.pd
Histotripsy Homogenization of the Prostate: Thresholds for Cavitation Damage of Periprostatic Structures
Background and Purpose: Histotripsy is a noninvasive, pulsed ultrasound technology that produces mechanically homogenized tissue within targeted volumes. Previous work has demonstrated prostatic tissue debulking in a canine model. The aim was to establish safety thresholds by evaluating histologic changes of urinary sphincter, neurovascular bundle (NVB), and rectum after targeted histotripsy treatment of these critical structures. Materials and Methods: Rectum, urinary sphincter, and NVB in five anesthetized canines were targeted for histotripsy treatment (50 total points). Locations received 1k, 10k, or 100k acoustic pulses (4 microsecond, 1-MHz) at a repetition frequency of 500-Hz. Canine subjects were euthanized immediately (2), survived 3 days (1), or 2 weeks (3) after treatment. Prostates, periprostatic tissue, and rectum were harvested and processed for histology. Results: The sphincter was structurally intact with minimal muscle fiber disruption even after 100k pulses (n=10). Undamaged nerves, arteries, and veins of the NVB were seen despite mechanical homogenization of surrounding loose connective tissue (n=19). The rectum, however, exhibited dose-dependent damage (n=20). 1k pulses yielded mild submucosal hemorrhage. 10k pulses resulted in moderate collagen disruption and focal mucosal homogenization. 100k pulses produced damage to the mucosa and muscularis propria with extensive hemorrhage and collagen disruption. One canine treated with 100k pulses needed early euthanasia (day 3) because of complications from a urine leak. Conclusions: Histotripsy histologic tissue effect varied based on targeted structure with substantial structural preservation of NVB and sphincter. Rectal subclinical damage was apparent after 1k pulses and increased in extent and severity with escalating doses. Future work will include assessment of functional outcomes and refinement of these initial safety thresholds.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90446/1/end-2E2010-2E0648.pd
Etiology of severe childhood pneumonia in the Gambia, West Africa, determined by conventional and molecular microbiological analyses of lung and pleural aspirate samples.
Molecular analyses of lung aspirates from Gambian children with severe pneumonia detected pathogens more frequently than did culture and showed a predominance of bacteria, principally Streptococcus pneumoniae, >75% being of serotypes covered by current pneumococcal conjugate vaccines. Multiple pathogens were detected frequently, notably Haemophilus influenzae (mostly nontypeable) together with S. pneumoniae
Observation of interstellar lithium in the low-metallicity Small Magellanic Cloud
The primordial abundances of light elements produced in the standard theory
of Big Bang nucleosynthesis (BBN) depend only on the cosmic ratio of baryons to
photons, a quantity inferred from observations of the microwave background. The
predicted primordial 7Li abundance is four times that measured in the
atmospheres of Galactic halo stars. This discrepancy could be caused by
modification of surface lithium abundances during the stars' lifetimes or by
physics beyond the Standard Model that affects early nucleosynthesis. The
lithium abundance of low-metallicity gas provides an alternative constraint on
the primordial abundance and cosmic evolution of lithium that is not
susceptible to the in situ modifications that may affect stellar atmospheres.
Here we report observations of interstellar 7Li in the low-metallicity gas of
the Small Magellanic Cloud, a nearby galaxy with a quarter the Sun's
metallicity. The present-day 7Li abundance of the Small Magellanic Cloud is
nearly equal to the BBN predictions, severely constraining the amount of
possible subsequent enrichment of the gas by stellar and cosmic-ray
nucleosynthesis. Our measurements can be reconciled with standard BBN with an
extremely fine-tuned depletion of stellar Li with metallicity. They are also
consistent with non-standard BBN.Comment: Published in Nature. Includes main text and Supplementary
Information. Replaced with final title and abstrac
Patients presenting with miliaria while wearing flame resistant clothing in high ambient temperatures: a case series
<p>Abstract</p> <p>Introduction</p> <p>Clothing can be a cause of occupational dermatitis. Frequent causes of clothing-related dermatological problems can be the fabric itself and/or chemical additives used in the laundering process, friction from certain fabrics excessively rubbing the skin, or heat retention from perspiration-soaked clothing in hot working environments. To the best of our knowledge, these are the first reported cases of miliaria rubra associated with prolonged use of flame resistant clothing in the medical literature.</p> <p>Case presentation</p> <p>We report 18 cases (14 men and 4 women, with an age range of 19 to 37 years) of moderate to severe skin irritation associated with wearing flame resistant clothing in hot arid environments (temperature range: 39 to 50°C, 5% to 25% relative humidity). We describe the medical history in detail of a 23-year-old Caucasian woman and a 31-year-old African-American man. A summary of the other 16 patients is also provided.</p> <p>Conclusions</p> <p>These cases illustrate the potential serious nature of miliaria with superimposed <it>Staphylococcus </it>infections. All 18 patients fully recovered with topical skin treatment and modifications to their dress ensemble. Clothing, in particular blend fabrics, must be thoroughly laundered to adequately remove detergent residue. While in hot environments, individuals with sensitive skin should take the necessary precautions such as regular changing of clothing and good personal hygiene to ensure that their skin remains as dry and clean as possible. It is also important that they report to their health care provider as soon as skin irritation or rash appears to initiate any necessary medical procedures. Miliaria rubra can take a week or longer to clear, so removal of exposure to certain fabric types may be necessary.</p
The Dawn of Open Access to Phylogenetic Data
The scientific enterprise depends critically on the preservation of and open
access to published data. This basic tenet applies acutely to phylogenies
(estimates of evolutionary relationships among species). Increasingly,
phylogenies are estimated from increasingly large, genome-scale datasets using
increasingly complex statistical methods that require increasing levels of
expertise and computational investment. Moreover, the resulting phylogenetic
data provide an explicit historical perspective that critically informs
research in a vast and growing number of scientific disciplines. One such use
is the study of changes in rates of lineage diversification (speciation -
extinction) through time. As part of a meta-analysis in this area, we sought to
collect phylogenetic data (comprising nucleotide sequence alignment and tree
files) from 217 studies published in 46 journals over a 13-year period. We
document our attempts to procure those data (from online archives and by direct
request to corresponding authors), and report results of analyses (using
Bayesian logistic regression) to assess the impact of various factors on the
success of our efforts. Overall, complete phylogenetic data for ~60% of these
studies are effectively lost to science. Our study indicates that phylogenetic
data are more likely to be deposited in online archives and/or shared upon
request when: (1) the publishing journal has a strong data-sharing policy; (2)
the publishing journal has a higher impact factor, and; (3) the data are
requested from faculty rather than students. Although the situation appears
dire, our analyses suggest that it is far from hopeless: recent initiatives by
the scientific community -- including policy changes by journals and funding
agencies -- are improving the state of affairs
Quantum Holographic Encoding in a Two-dimensional Electron Gas
The advent of bottom-up atomic manipulation heralded a new horizon for
attainable information density, as it allowed a bit of information to be
represented by a single atom. The discrete spacing between atoms in condensed
matter has thus set a rigid limit on the maximum possible information density.
While modern technologies are still far from this scale, all theoretical
downscaling of devices terminates at this spatial limit. Here, however, we
break this barrier with electronic quantum encoding scaled to subatomic
densities. We use atomic manipulation to first construct open
nanostructures--"molecular holograms"--which in turn concentrate information
into a medium free of lattice constraints: the quantum states of a
two-dimensional degenerate Fermi gas of electrons. The information embedded in
the holograms is transcoded at even smaller length scales into an atomically
uniform area of a copper surface, where it is densely projected into both two
spatial degrees of freedom and a third holographic dimension mapped to energy.
In analogy to optical volume holography, this requires precise amplitude and
phase engineering of electron wavefunctions to assemble pages of information
volumetrically. This data is read out by mapping the energy-resolved electron
density of states with a scanning tunnelling microscope. As the projection and
readout are both extremely near-field, and because we use native quantum states
rather than an external beam, we are not limited by lensing or collimation and
can create electronically projected objects with features as small as ~0.3 nm.
These techniques reach unprecedented densities exceeding 20 bits/nm2 and place
tens of bits into a single fermionic state.Comment: Published online 25 January 2009 in Nature Nanotechnology; 12 page
manuscript (including 4 figures) + 2 page supplement (including 1 figure);
supplementary movie available at http://mota.stanford.ed
Relationship of cognitive function in patients with schizophrenia in remission to disability: a cross-sectional study in an Indian sample
Background: Cognitive deficits in various domains have been consistently replicated in patients with schizophrenia. Most studies looking at the relationship between cognitive dysfunction and functional disability are from developed countries. Studies from developing countries are few. The purpose of the present study was to compare the neurocognitive function in patients with schizophrenia who were in remission with that of normal controls and to determine if there is a relationship between measures of cognition and functional disability.
<p/>Methods: This study was conducted in the Psychiatric Unit of a General Hospital in Mumbai, India. Cognitive function in 25 patients with schizophrenia in remission was compared to 25 normal controls. Remission was confirmed using the brief psychiatric rating scale (BPRS) and scale for the assessment of negative symptoms (SANS). Subjects were administered a battery of cognitive tests covering aspects of memory, executive function and attention. The results obtained were compared between the groups. Correlation analysis was used to look for relationship between illness factors, cognitive function and disability measured using the Indian disability evaluation and assessment scale.
<p/>Results: Patients with schizophrenia showed significant deficits on tests of attention, concentration, verbal and visual memory and tests of frontal lobe/executive function. They fared worse on almost all the tests administered compared to normal controls. No relationship was found between age, duration of illness, number of years of education and cognitive function. In addition, we did not find a statistically significant relationship between cognitive function and scores on the disability scale.
<p/>Conclusion: The data suggests that persistent cognitive deficits are seen in patients with schizophrenia under remission. The cognitive deficits were not associated with symptomatology and functional disability. It is possible that various factors such as employment and family support reduce disability due to schizophrenia in developing countries like India. Further studies from developing countries are required to explore the relationship between cognitive deficits, functional outcome and the role of socio-cultural variables as protective factors
Preoperative Psoas Muscle Size Predicts Postoperative Delirium in Older Adults Undergoing Surgery: A Pilot Cohort Study
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136001/1/jgs14571.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136001/2/jgs14571_am.pd
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