847 research outputs found
Effective spinless fermions in the strong coupling Kondo model
Starting from the two-orbital Kondo-lattice model with classical t_2g spins,
an effective spinless fermion model is derived for strong Hund coupling J_H
with a projection technique. The model is studied by Monte Carlo simulations
and analytically using a uniform hopping approximation. The results for the
spinless fermion model are in remarkable agreement with those of the original
Kondo-lattice model, independent of the carrier concentration, and even for
moderate Hund coupling J_H. Phase separation, the phase diagram in uniform
hopping approximation, as well as spectral properties including the formation
of a pseudo-gap are discussed for both the Kondo-lattice and the effective
spinless fermion model in one and three dimensions.Comment: Revtex4, 10 pages, 15 figures, typos correcte
Orthopedic surgery increases atherosclerotic lesions and necrotic core area in ApoE-/- mice
Background and aims Observational studies show a peak incidence of cardiovascular events after major surgery. For example, the risk of myocardial infarction increases 25-fold early after hip replacement. The acuteness of this increased risk suggests abrupt enhancement in plaque vulnerability, which may be related to intra-plaque inflammation, thinner fibrous cap and/or necrotic core expansion. We hypothesized that acute systemic inflammation following major orthopedic surgery induces such changes. Methods ApoE−/− mice were fed a western diet for 10 weeks. Thereafter, half the mice underwent mid-shaft femur osteotomy followed by realignment with an intramedullary K-wire, to mimic major orthopedic surgery. Mice were sacrificed 5 or 15 days post-surgery (n = 22) or post-saline injection (n = 13). Serum amyloid A (SAA) was measured as a marker of systemic inflammation. Paraffin embedded slides of the aortic root were stained to measure total plaque area and to quantify fibrosis, calcification, necrotic core, and inflammatory cells. Results Surgery mice showed a pronounced elevation of serum amyloid A (SAA) and developed increased plaque and necrotic core area already at 5 days, which reached significance at 15 days (p = 0.019; p = 0.004 for plaque and necrotic core, respectively). Macrophage and lymphocyte density significantly decreased in the surgery group compared to the control group at 15 days (p = 0.037; p = 0.024, respectively). The density of neutrophils and mast cells remained unchanged. Conclusions Major orthopedic surgery in ApoE−/− mice triggers a systemic inflammatory response. Atherosclerotic plaque area is enlarged after surgery mainly due to an increase of the necrotic core. The role of intra-plaque inflammation in this response to surgical injury remains to be fully elucidated. © 2016 Elsevier Ireland Lt
Introduction of primary screening using high-risk HPV DNA detection in the Dutch cervical cancer screening programme:a population-based cohort study
Background: In January 2017, the Dutch cervical cancer screening programme transitioned from cytomorphological to primary high-risk HPV (hrHPV) DNA screening, including the introduction of self-sampling, for women aged between 30 and 60 years. The Netherlands was the first country to switch to hrHPV screening at the national level. We investigated the health impact of this transition by comparing performance indicators from the new hrHPV-based programme with the previous cytology-based programme. Methods: We obtained data from the Dutch nationwide network and registry of histo- and cytopathology (PALGA) for 454,573 women eligible for screening in 2017 who participated in the hrHPV-based programme between 1 January 2017 and 30 June 2018 (maximum follow-up of almost 21 months) and for 483,146 women eligible for screening in 2015 who participated in the cytology-based programme between 1 January 2015 and 31 March 2016 (maximum follow-up of 40 months). We compared indicators of participation (participation rate), referral (screen positivity; referral rate) and detection (cervical intraepithelial neoplasia (CIN) detection; number of referrals per detected CIN lesion). Results: Participation in the hrHPV-based programme was significantly lower than that in the cytology-based programme (61% vs 64%). Screen positivity and direct referral rates were significantly higher in the hrHPV-based programme (positivity rate: 5% vs 9%; referral rate: 1% vs 3%). CIN2+ detection increased from 11 to 14 per 1000 women screened. Overall, approximately 2.2 times more clinical irrelevant findings (i.e. ≤CIN1) were found in the hrHPV-based programme, compared with approximately 1·3 times more clinically relevant findings (i.e. CIN2+); this difference was mostly due to a national policy change recommending colposcopy, rather than observation, of hrHPV-positive, ASC-US/LSIL results in the hrHPV-based programme. Conclusions: This is the first time that comprehensive results of nationwide implementation of hrHPV-based screening have been reported using high-quality data with a long follow-up. We have shown that both benefits and potential harms are higher in one screening round of a well-implemented hrHPV-based screening programme than in an established cytology-based programme. Lower participation in the new hrHPV programme may be due to factors such as invitation policy changes and the phased roll-out of the new programme. Our findings add further to evidence from trials and modelling studies on the effectiveness of hrHPV-based screening
Uniform hopping approach to the FM Kondo Model at finite temperature
We study the ferromagnetic Kondo model with classical corespins via unbiased
Monte-Carlo simulations and derive a simplified model for the treatment of the
corespins at any temperature. Our simplified model captures the main aspects of
the Kondo model and can easily be evaluated both numerically and analytically.
It provides a better qualitative understanding of the physical features of the
Kondo model and rationalizes the Monte-Carlo results, including the spectral
density A_k(omega) of a 1D chain with nearest neighbor Coulomb repulsion. By
calculating the specific heat and the susceptibility of systems up to size
16^3, we determine the Curie temperature of the 3D one-orbital double-exchange
model, which agrees with experimental values.Comment: 11 pages, 9 figures, RevTex4, additional references cite
Genetic mapping and transcription analyses of resistance gene loci in potato using NBS profiling
The influence of micrometastases on prognosis and survival in stage I-II colon cancer patients: the Enroute⊕ Study
<p>Abstract</p> <p>Background</p> <p>The presence of lymph node metastases remains the most reliable prognostic predictor and the gold indicator for adjuvant treatment in colon cancer (CC). In spite of a potentially curative resection, 20 to 30% of CC patients testing negative for lymph node metastases (i.e. pN0) will subsequently develop locoregional and/or systemic metastases within 5 years. The presence of occult nodal isolated tumor cells (ITCs) and/or micrometastases (MMs) at the time of resection predisposes CC patients to high risk for disease recurrence. These pN0<sub>micro+ </sub>patients harbouring occult micrometastases may benefit from adjuvant treatment. The purpose of the present study is to delineate the subset of pN0 patients with micrometastases (pN0<sub>micro+</sub>) and evaluate the benefits from adjuvant chemotherapy in pN0<sub>micro+ </sub>CC patients.</p> <p>Methods/design</p> <p>EnRoute+ is an open label, multicenter, randomized controlled clinical trial. All CC patients (age above 18 years) without synchronous locoregional lymph node and/or systemic metastases (clinical stage I-II disease) and operated upon with curative intent are eligible for inclusion. All resected specimens of patients are subject to an <it>ex vivo </it>sentinel lymph node mapping procedure (SLNM) following curative resection. The investigation for micrometastases in pN0 patients is done by extended serial sectioning and immunohistochemistry for pan-cytokeratin in sentinel lymph nodes which are tumour negative upon standard pathological examination. Patients with ITC/MM-positive sentinel lymph nodes (pN0<sub>micro+</sub>) are randomized for adjuvant chemotherapy following the CAPOX treatment scheme or observation. The primary endpoint is 3-year disease free survival (DFS).</p> <p>Discussion</p> <p>The EnRoute+ study is designed to improve prognosis in high-risk stage I/II pN0 <sub>micro+ </sub>CC patients by reducing disease recurrence by adjuvant chemotherapy.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01097265">NCT01097265</a></p
A symptom-based algorithm for calcium management after thyroid surgery: a prospective multicenter study
Objective: Evidence-based treatment guidelines for the management of postthyroidectomy hypocalcemia are absent. The aim of this study was to evaluate a newly developed symptom-based treatment algorithm including a protocolized attempt to phase out supplementation.
Methods: In a prospective multicenter study, patients were treated according to the new algorithm and compared to a historical cohort of patients treated with a biochemically based approach. The primary outcome was the proportion of patients receiving calcium and/or alfacalcidol supplementation. Secondary outcomes were calcium-related complications and predictors for supplementation.
Results: One hundred thirty-four patients were included prospectively, and compared to 392 historical patients. The new algorithm significantly reduced the proportion of patients treated with calcium and/or alfacalcidol during the first postoperative year (odds ratio (OR): 0.36 (95% CI: 0.23–0.54), P < 0.001), and persistently at 12 months follow-up (OR: 0.51 (95% CI: 0.28–0.90), P < 0.05). No severe calcium-related complications occurred, even though calcium-related visits to the emergency department and readmissions increased (OR: 11.5 (95% CI: 4.51–29.3), P <0.001) and (OR: 3.46 (95% CI: 1.58–7.57), P < 0.05), respectively. The proportional change in pre- to post operative parathyroid hormone (PTH) was an independent predictor for supplementation (OR: 1.04 (95% CI: 1.02–1.07), P < 0.05).
Conclusions: Symptom-based management of postthyroidectomy hypocalcemia and a protocolized attempt to phase out supplementation safely reduce d the proportion of patients receiving supplementation, although the number of calcium-related hospital visits increased. For the future, we envision a more individualized treatment approach for patients at risk for delayed symptomatic hypocalcemia, including the proportional change in pre- to post- operative PTH
Biallelic and monoallelic ESR2 variants associated with 46,XY disorders of sex development
Purpose: Disorders or differences of sex development (DSDs) are rare congenital conditions characterized by atypical sex development. Despite advances in genomic technologies, the molecular cause remains unknown in 50% of cases.
Methods: Homozygosity mapping and whole-exome sequencing revealed an ESR2 variant in an individual with syndromic 46, XY DSD. Additional cases with 46, XY DSD underwent whole-exome sequencing and targeted next-generation sequencing of ESR2. Functional characterization of the identified variants included luciferase assays and protein structure analysis. Gonadal ESR2 expression was assessed in human embryonic data sets and immunostaining of estrogen receptor-beta (ER-beta) was performed in an 8-week-old human male embryo.
Results: We identified a homozygous ESR2 variant, c.541_543del p. (Asn181del), located in the highly conserved DNA-binding domain of ER-beta, in an individual with syndromic 46, XY DSD. Two additional heterozygous missense variants, c.251G>T p.(Gly84Val) and c.1277T>G p.(Leu426Arg), located in the N-terminus and the ligand-binding domain of ER-beta, were found in unrelated, nonsyndromic 46, XY DSD cases. Significantly increased transcriptional activation and an impact on protein conformation were shown for the p.(Asn181del) and p.(Leu426Arg) variants. Testicular ESR2 expression was previously documented and ER-beta immunostaining was positive in the developing intestine and eyes.
Conclusion: Our study supports a role for ESR2 as a novel candidate gene for 46, XY DSD
Llama Antibody Fragments Recognizing Various Epitopes of the CD4bs Neutralize a Broad Range of HIV-1 Subtypes A, B and C
Many of the neutralising antibodies, isolated to date, display limited activities against the globally most prevalent HIV-1 subtypes A and C. Therefore, those subtypes are considered to be an important target for antibody-based therapy. Variable domains of llama heavy chain antibodies (VHH) have some superior properties compared with classical antibodies. Therefore we describe the application of trimeric forms of envelope proteins (Env), derived from HIV-1 of subtype A and B/C, for a prolonged immunization of two llamas. A panel of VHH, which interfere with CD4 binding to HIV-1 Env were selected with use of panning. The results of binding and competition assays to various Env, including a variant with a stabilized CD4-binding state (gp120Ds2), cross-competition experiments, maturation analysis and neutralisation assays, enabled us to classify the selected VHH into three groups. The VHH of group I were efficient mainly against viruses of subtype A, C and B′/C. The VHH of group II resemble the broadly neutralising antibody (bnmAb) b12, neutralizing mainly subtype B and C viruses, however some had a broader neutralisation profile. A representative of the third group, 2E7, had an even higher neutralization breadth, neutralizing 21 out of the 26 tested strains belonging to the A, A/G, B, B/C and C subtypes. To evaluate the contribution of certain amino acids to the potency of the VHH a small set of the mutants were constructed. Surprisingly this yielded one mutant with slightly improved neutralisation potency against 92UG37.A9 (subtype A) and 96ZM651.02 (subtype C). These findings and the well-known stability of VHH indicate the potential application of these VHH as anti-HIV-1 microbicides
A Reliability-Generalization Study of Journal Peer Reviews: A Multilevel Meta-Analysis of Inter-Rater Reliability and Its Determinants
Background: This paper presents the first meta-analysis for the inter-rater reliability (IRR) of journal peer reviews. IRR is defined as the extent to which two or more independent reviews of the same scientific document agree. Methodology/Principal Findings: Altogether, 70 reliability coefficients (Cohen’s Kappa, intra-class correlation [ICC], and Pearson product-moment correlation [r]) from 48 studies were taken into account in the meta-analysis. The studies were based on a total of 19,443 manuscripts; on average, each study had a sample size of 311 manuscripts (minimum: 28, maximum: 1983). The results of the meta-analysis confirmed the findings of the narrative literature reviews published to date: The level of IRR (mean ICC/r 2 =.34, mean Cohen’s Kappa =.17) was low. To explain the study-to-study variation of the IRR coefficients, meta-regression analyses were calculated using seven covariates. Two covariates that emerged in the metaregression analyses as statistically significant to gain an approximate homogeneity of the intra-class correlations indicated that, firstly, the more manuscripts that a study is based on, the smaller the reported IRR coefficients are. Secondly, if the information of the rating system for reviewers was reported in a study, then this was associated with a smaller IRR coefficient than if the information was not conveyed. Conclusions/Significance: Studies that report a high level of IRR are to be considered less credible than those with a low level o
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