550 research outputs found
Interference measurements of non-Abelian e/4 & Abelian e/2 quasiparticle braiding
The quantum Hall states at filling factors and are expected
to have Abelian charge quasiparticles and non-Abelian charge
quasiparticles. For the first time we report experimental evidence for the
non-Abelian nature of excitations at and examine the fermion parity,
a topological quantum number of an even number of non-Abelian quasiparticles,
by measuring resistance oscillations as a function of magnetic field in
Fabry-P\'erot interferometers using new high purity heterostructures. The phase
of observed oscillations is reproducible and stable over long times
(hours) near and , indicating stability of the fermion parity.
When phase fluctuations are observed, they are predominantly phase flips,
consistent with fermion parity change. We also examine lower-frequency
oscillations attributable to Abelian interference processes in both states.
Taken together, these results constitute new evidence for the non-Abelian
nature of quasiparticles; the observed life-time of their combined
fermion parity further strengthens the case for their utility for topological
quantum computation.Comment: A significantly revised version; 54 double-column pages containing 14
pages of main text + Supplementary Materials. The figures, which include a
number of new figures, are now incorporated into the tex
The targeted delivery of multicomponent cargos to cancer cells by nanoporous particle-supported lipid bilayers.
Encapsulation of drugs within nanocarriers that selectively target malignant cells promises to mitigate side effects of conventional chemotherapy and to enable delivery of the unique drug combinations needed for personalized medicine. To realize this potential, however, targeted nanocarriers must simultaneously overcome multiple challenges, including specificity, stability and a high capacity for disparate cargos. Here we report porous nanoparticle-supported lipid bilayers (protocells) that synergistically combine properties of liposomes and nanoporous particles. Protocells modified with a targeting peptide that binds to human hepatocellular carcinoma exhibit a 10,000-fold greater affinity for human hepatocellular carcinoma than for hepatocytes, endothelial cells or immune cells. Furthermore, protocells can be loaded with combinations of therapeutic (drugs, small interfering RNA and toxins) and diagnostic (quantum dots) agents and modified to promote endosomal escape and nuclear accumulation of selected cargos. The enormous capacity of the high-surface-area nanoporous core combined with the enhanced targeting efficacy enabled by the fluid supported lipid bilayer enable a single protocell loaded with a drug cocktail to kill a drug-resistant human hepatocellular carcinoma cell, representing a 10(6)-fold improvement over comparable liposomes
Multifaceted contributions : health workers and smallpox eradication in India
Smallpox eradication in South Asia was a result of the efforts of many grades of health-workers. Working from within the confines of international organisations and government structures, the role of the field officials, who were of various nationalities and also drawn from the cities and rural enclaves of the countries in these regions, was crucial to the development and deployment of policies. However, the role of these personnel is often downplayed in official histories and academic histories, which highlight instead the roles played by a handful of senior officials within the World Health Organization and the federal governments in the sub-continent. This article attempts to provide a more rounded assessment of the complex situation in the field. In this regard, an effort is made to underline the great usefulness of the operational flexibility displayed by field officers, wherein lessons learnt in the field were made an integral part of deploying local campaigns; careful engagement with the communities being targeted, as well as the employment of short term workers from amongst them, was an important feature of this work
Does health insurance coverage or improved quality protect better against out-of-pocket payments? Experimental evidence from the Philippines
This paper explores whether health insurance coverage or improved quality at the hospital level protect better against out-of-pocket payments. Using data from a randomized policy experiment in the Philippines, we found that interventions to expand insurance coverage and improve provider quality both had an impact on out-of-pocket payments. The sample consists of 3121 child-patient patient observations across 30 hospitals either at baseline in 2003/04 or at the follow-up in 2007/08. Compared to controls, interventions that expanded insurance and provided performance-based provider payments to improve quality both resulted in a decline in out-of-pocket spending (21% decline, p-value = 0.061; and 24% decline, p-value = 0.017, respectively). With lower out-of-pocket payments for hospital care, monthly household spending on personal hygiene rose by 0.9 (p-value = 0.026) and 0.6 US$ (p-value = 0.098) under the expanded insurance and provider payment interventions, respectively, amounting to roughly a 40–60% increase relative to the controls. With the current surge for health insurance expansion in developing countries, our study suggests paying increased and possibly, equal attention to supply-side interventions will have similar impacts with operational simplicity and greater provider accountability
Radical Surgery in the Treatment of Localized Carcinoma of the Prostate
New methods of early detection combined with recent advances in surgical techniques have resulted in more patients undergoing radical surgery for treatment of localized carcinoma of the prostate. Over 350 radical prostatectomies have been performed by our group since January 1987. We review the role of radical prostatectomy in the treatment of prostate cancer and our experience with 100 patients undergoing radical retropubic prostatectomy since the advent of nerve-sparing techniques to preserve potency
Performance-based financing as a health system reform : mapping the key dimensions for monitoring and evaluation
Peer reviewedPublisher PD
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Impact of optical coherence tomography on diagnostic decision-making by UK community optometrists: a clinical vignette study.
PURPOSE: In recent years, there has been widespread investment in imaging technologies by community optometrists in the UK, most notably optical coherence tomography (OCT). The aim of the current study was to determine the value of OCT in the diagnosis of posterior segment diseases in a representative sample of community optometrists using a clinical vignette methodology.
METHODS: A group of community optometrists (n = 50) initially completed a standardised training package on OCT interpretation followed by a computer-based assessment featuring 52 clinical vignettes, containing images of healthy (n = 8) or glaucomatous (n = 18) discs or healthy (n = 8) or diseased (n = 18) fundi. Each vignette featured either a single fundus/disc photographic image, or a combination of a fundus/disc image with the corresponding OCT scan. An expert panel confirmed that the fundus images presented alone and those in combination with OCT data were of a similar level of difficulty and that the cases were typical of those seen in primary care. For each case, the optometrist selected their diagnosis from a pull-down list and reported their confidence in their decision using a 10-point Likert scale. Pairwise comparisons of the fundus image alone and fundus image/OCT combination were made for both diagnostic performance and confidence.
RESULTS: The mean percentage of correct diagnoses using fundus imaging alone was 62% (95% CI 59-64%) and for the combination of fundus image/OCT was 80% (95% CI 77-82%). The mean false negative rate with fundus alone was 27% reducing to 13% with the OCT combination. Median confidence scores for fundus imaging alone was 8.0 (IQR 7.0-8.0) and 8.3 (IQR 8.0-9.0) for the combination. Improvements in performance and confidence were statistically significant (p < 0.001).
CONCLUSION: The results from this vignette study suggests that OCT improves optometrists' diagnostic performance compared to fundus observation alone. These initial results suggest that OCT provides valuable additional data that could augment case-finding for glaucoma and retinal disease; however, further research is needed to assess its diagnostic performance in a routine clinical practice setting
Validation of the treatment identification strategy of the HEDIS addiction quality measures: concordance with medical record review
<p>Abstract</p> <p>Background</p> <p>Strategies to accurately identify the occurrence of specific health care events in administrative data is central to many quality improvement and research efforts. Many health care quality measures have treatment identification strategies based on diagnosis and procedure codes - an approach that is inexpensive and feasible but usually of unknown validity. In this study, we examined if the diagnosis/procedure code combinations used in the 2006 HEDIS Initiation and Engagement quality measures to identify instances of addiction treatment have high concordance with documentation of addiction treatment in clinical progress notes.</p> <p>Methods</p> <p>Four type of records were randomly sampled from VHA electronic medical data: (a) Outpatient records from a substance use disorder (SUD) specialty clinic with a HEDIS-qualified substance use disorder (SUD) diagnosis/CPT code combination (n = 700), (b) Outpatient records from a non-SUD setting with a HEDIS-qualified SUD diagnosis/CPT code combination (n = 592), (c) Specialty SUD Inpatient/residential records that included a SUD diagnosis (n = 700), and (d) Non-SUD specialty Inpatient/residential records that included a SUD diagnosis (n = 700). Clinical progress notes for the sampled records were extracted and two raters classified each as documenting or not documenting addiction treatment. Rates of concordance between the HEDIS addiction treatment identification strategy and the raters' judgments were calculated for each record type.</p> <p>Results</p> <p>Within SUD outpatient clinics and SUD inpatient specialty units, 92% and 98% of sampled records had chart evidence of addiction treatment. Of outpatient encounters with a qualifying diagnosis/procedure code combination outside of SUD clinics, 63% had chart evidence of addiction treatment. Within non-SUD specialty inpatient units, only 46% of sampled records had chart evidence of addiction treatment.</p> <p>Conclusions</p> <p>For records generated in SUD specialty settings, the HEDIS strategy of identifying SUD treatment with diagnosis and procedure codes has a high concordance with chart review. The concordance rate outside of SUD specialty settings is much lower and highly variable between facilities. Therefore, some patients may be counted as meeting the 2006 HEDIS Initiation and Engagement criteria without having received the specified amount (or any) addiction treatment.</p
A Pan-HPV Vaccine Based on Bacteriophage PP7 VLPs Displaying Broadly Cross-Neutralizing Epitopes from the HPV Minor Capsid Protein, L2
Current human papillomavirus (HPV) vaccines that are based on virus-like particles (VLPs) of the major capsid protein L1 largely elicit HPV type-specific antibody responses. In contrast, immunization with the HPV minor capsid protein L2 elicits antibodies that are broadly cross-neutralizing, suggesting that a vaccine targeting L2 could provide more comprehensive protection against infection by diverse HPV types. However, L2-based immunogens typically elicit much lower neutralizing antibody titers than L1 VLPs. We previously showed that a conserved broadly neutralizing epitope near the N-terminus of L2 is highly immunogenic when displayed on the surface of VLPs derived from the bacteriophage PP7. Here, we report the development of a panel of PP7 VLP-based vaccines targeting L2 that protect mice from infection with carcinogenic and non-carcinogenic HPV types that infect the genital tract and skin.L2 peptides from eight different HPV types were displayed on the surface of PP7 bacteriophage VLPs. These recombinant L2 VLPs, both individually and in combination, elicited high-titer anti-L2 IgG serum antibodies. Immunized mice were protected from high dose infection with HPV pseudovirus (PsV) encapsidating a luciferase reporter. Mice immunized with 16L2 PP7 VLPs or 18L2 PP7 VLPs were nearly completely protected from both PsV16 and PsV18 challenge. Mice immunized with the mixture of eight L2 VLPs were strongly protected from genital challenge with PsVs representing eight diverse HPV types and cutaneous challenge with HPV5 PsV.VLP-display of a cross-neutralizing HPV L2 epitope is an effective approach for inducing high-titer protective neutralizing antibodies and is capable of offering protection from a spectrum of HPVs associated with cervical cancer as well as genital and cutaneous warts
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