1,282 research outputs found
Minimising bulk lifetime degradation during the processing of interdigitated back contact silicon solar cell
In this work, we develop a fabrication process for an interdigitated back contact solar cell using BBr3 diffusion to form the p+ region and POCl3 diffusion to form the n+ regions. We use the industry standard technology computer-aided design modelling package, Synopsys Sentaurus, to optimize the geometry of the device using doping profiles derived from electrochemical capacitance voltage measurements. Cells are fabricated using n-type float-zone silicon substrates with an emitter fraction of 60%, with localized back surface field and contact holes. Key factors affecting cell performance are identified including the impact of e-beam evaporation, dry etch damage, and bulk defects in the float zone silicon substrate. It is shown that a preoxidation treatment of the wafer can lead to a 2 ms improvement in bulk minority carrier lifetime at the cell level, resulting in a 4% absolute efficiency boost
Extracorporeal Irradiation and Reimplantation with Total Hip Arthroplasty for Periacetabular Pelvic Resections: A Review of 9 Cases
The high burden of alcoholic cirrhosis in privately insured persons in the United States
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146288/1/hep29887-sup-0001-suppinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146288/2/hep29887_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146288/3/hep29887.pd
Padded Helmet Shell Covers in American Football: A Comprehensive Laboratory Evaluation with Preliminary On-Field Findings
Protective headgear effects measured in the laboratory may not always
translate to the field. In this study, we evaluated the impact attenuation
capabilities of a commercially available padded helmet shell cover in the
laboratory and field. In the laboratory, we evaluated the efficacy of the
padded helmet shell cover in attenuating impact magnitude across six impact
locations and three impact velocities when equipped to three different helmet
models. In a preliminary on-field investigation, we used instrumented
mouthguards to monitor head impact magnitude in collegiate linebackers during
practice sessions while not wearing the padded helmet shell covers (i.e., bare
helmets) for one season and whilst wearing the padded helmet shell covers for
another season. The addition of the padded helmet shell cover was effective in
attenuating the magnitude of angular head accelerations and two brain injury
risk metrics (DAMAGE, HARM) across most laboratory impact conditions, but did
not significantly attenuate linear head accelerations for all helmets. Overall,
HARM values were reduced in laboratory impact tests by an average of 25% at 3.5
m/s (range: 9.7 - 39.6%), 18% at 5.5 m/s (range: -5.5 - 40.5%), and 10% at 7.4
m/s (range: -6.0 - 31.0%). However, on the field, no significant differences in
any measure of head impact magnitude were observed between the bare helmet
impacts and padded helmet impacts. Further laboratory tests were conducted to
evaluate the ability of the padded helmet shell cover to maintain its
performance after exposure to repeated, successive impacts and across a range
of temperatures. This research provides a detailed assessment of padded helmet
shell covers and supports the continuation of in vivo helmet research to
validate laboratory testing results.Comment: 49 references, 8 figure
Microarrays
Microarrays are revolutionizing genetics by making it possible to genotype hundreds of thousands of DNA markers and to assess the expression (RNA transcripts) of all of the genes in the genome. Microarrays are slides the size of a postage stamp that contain millions of DNA sequences to which single-stranded DNA or RNA can hybridize. This miniaturization requires little DNA or RNA and makes the method fast and inexpensive; multiple assays of each target make the method highly accurate. DNA microarrays with hundreds of thousands of DNA markers have made it possible to conduct systematic scans of the entire genome to identify genetic associations with complex disorders or dimensions likely to be influenced by many genes of small effect size. RNA microarrays can provide snapshots of gene expression across all of the genes in the genome at any time in any tissue, which has far-reaching applications such as structural and functional âgenetic neuroimagingâ and providing a biological basis for understanding environmental influence
Detection of a reservoir of bedaquiline / clofazimine resistance associated variants in Mycobacterium tuberculosis predating the antibiotic era
Drug resistance in tuberculosis (TB) poses a major ongoing challenge to public health. The recent
inclusion of bedaquiline into TB drug regimens has improved treatment outcomes, but this advance is
threatened by the emergence of strains of Mycobacterium tuberculosis (Mtb) resistant to bedaquiline.
Clinical bedaquiline resistance is most frequently conferred by resistance-associated variants (RAVs)
in the Rv0678 gene which can also confer cross-resistance to clofazimine, another TB drug. We
compiled a dataset of 3,682 Mtb genomes, including 223 carrying Rv0678 bedaquiline RAVs. We
identified at least 15 cases where RAVs were present in the genomes of strains collected prior to the
use of bedaquiline in TB treatment regimes. Phylogenetic analyses point to multiple emergence events
and circulation of RAVs in Rv0678, often prior to the introduction of bedaquiline or clofazimine. We
also identify one case where the RAV Ile67fs is estimated to have emerged prior to the antibiotic era.
The presence of a pre-existing reservoir of bedaquiline-resistant Mtb strains augments the need for rapid
drug susceptibility testing and individualised regimen selection to safeguard the use of bedaquiline in
TB care and control
Clinical Features of High-Grade Extremity and Trunk Sarcomas in Patients Aged 80 Years and Older: Why Are Outcomes Inferior?
Background: The population of many countries is aging and a significant number of elderly patients with soft-tissue sarcoma are being seen at cancer centers. The unique therapeutic and prognostic implications of treating soft-tissue sarcoma in geriatric patients warrant further consideration in order to optimize outcomes.Patients and Methods: This is a single-institution retrospective study of consecutive non-metastatic primary extremity and trunk high-grade sarcomas surgically treated between 1996 and 2012, with at least 2 years of follow-up for survivors. Patient characteristics and oncological outcomes were compared between age groups (â„80 vs. <80 years), using Chi-square or Fisher-exact test and Log-Rank or Wilcoxon test, respectively. Deaths from other causes were censored for disease-specific survival estimation. A p< 0.05 was regarded as statistically significant.Results: A total of 333 cases were eligible for this study. Thirty-six patients (11%) were aged â„80 years. Unplanned surgery incidence and surgical margin status were comparable between the age groups. Five-year local-recurrence-free, metastasis-free and disease-specific survivals were 72% (â„80 years) vs. 90% (<80 years) (p = 0.004), 59 vs. 70% (p = 0.07) and 55 vs. 80% (p < 0.001), respectively. A significantly earlier first metastasis after surgery (8.3 months vs. 20.5 months, mean) and poorer survival after first metastasis (p = 0.03) were observed. Cox analysis revealed âage â„80 yearsâ as an independent risk factor for local failure and disease-specific mortality, with hazard ratios of 2.41 (95% CI: 1.09â5.32) and 2.52 (1.33â4.13), respectively. A competing risks analysis also showed that âage â„80 yearsâ was significantly associated with the disease-specific mortality.Conclusions: Oncological outcomes were significantly worse in high-grade sarcoma patients aged â„80 years. The findings of more frequent local failure regardless of a consistent primary treatment strategy, an earlier time to first metastasis after surgery, and poorer prognosis after first metastasis suggest that more aggressive tumor biology, in addition to multiple co-morbidity, may explain the inferiority
Formation of superdense hadronic matter in high energy heavy-ion collisions
We present the detail of a newly developed relativistic transport model (ART
1.0) for high energy heavy-ion collisions. Using this model, we first study the
general collision dynamics between heavy ions at the AGS energies. We then show
that in central collisions there exists a large volume of sufficiently
long-lived superdense hadronic matter whose local baryon and energy densities
exceed the critical densities for the hadronic matter to quark-gluon plasma
transition. The size and lifetime of this matter are found to depend strongly
on the equation of state. We also investigate the degree and time scale of
thermalization as well as the radial flow during the expansion of the
superdense hadronic matter. The flow velocity profile and the temperature of
the hadronic matter at freeze-out are extracted. The transverse momentum and
rapidity distributions of protons, pions and kaons calculated with and without
the mean field are compared with each other and also with the preliminary data
from the E866/E802 collaboration to search for experimental observables that
are sensitive to the equation of state. It is found that these inclusive,
single particle observables depend weakly on the equation of state. The
difference between results obtained with and without the nuclear mean field is
only about 20\%. The baryon transverse collective flow in the reaction plane is
also analyzed. It is shown that both the flow parameter and the strength of the
``bounce-off'' effect are very sensitive to the equation of state. In
particular, a soft equation of state with a compressibility of 200 MeV results
in an increase of the flow parameter by a factor of 2.5 compared to the cascade
case without the mean field. This large effect makes it possible to distinguish
the predictions from different theoretical models and to detect the signaturesComment: 55 pages, latex, + 39 figures available upon reques
Sensory Communication
Contains table of contents for Section 2, an introduction, reports on nine research projects and a list of publications.National Institutes of Health Grant 5 R01 DC00117National Institutes of Health Grant 2 R01 DC00270National Institutes of Health Grant 1 P01 DC00361National Institutes of Health Grant 2 R01 DC00100National Institutes of Health Grant FV00428National Institutes of Health Grant 5 R01 DC00126U.S. Air Force - Office of Scientific Research Grant AFOSR 90-200U.S. Navy - Office of Naval Research Grant N00014-90-J-1935National Institutes of Health Grant 5 R29 DC0062
Preparation of amino-substituted indenes and 1,4-dihydronaphthalenes using a one-pot multireaction approach: total synthesis of oxybenzo[c]phenanthridine alkaloids
Allylic trichloroacetimidates bearing a 2-vinyl or 2-allylaryl group have been designed as substrates for a one-pot, two-step multi-bond-forming process leading to the general preparation of aminoindenes and amino-substituted 1,4-dihydronaphthalenes. The synthetic utility of the privileged structures formed from this one-pot process was demonstrated with the total synthesis of four oxybenzo[c]phenanthridine alkaloids, oxychelerythrine, oxysanguinarine, oxynitidine, and oxyavicine. An intramolecular biaryl Heck coupling reaction, catalyzed using the HermannâBeller palladacycle was used to effect the key step during the synthesis of the natural products
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