Strange metal behavior is ubiquitous in correlated materials, ranging from cuprate superconductors to bilayer graphene, and may arise from physics beyond the quantum fluctuations of a Landau order ...parameter. In quantum-critical heavy-fermion antiferromagnets, such physics may be realized as critical Kondo entanglement of spin and charge and probed with optical conductivity. We present terahertz time-domain transmission spectroscopy on molecular beam epitaxy-grown thin films of YbRh
Si
, a model strange-metal compound. We observed frequency over temperature scaling of the optical conductivity as a hallmark of beyond-Landau quantum criticality. Our discovery suggests that critical charge fluctuations play a central role in the strange metal behavior, elucidating one of the long-standing mysteries of correlated quantum matter.
We investigate graphene-based optical absorbers that exploit guided mode resonances (GMRs) attaining theoretically perfect absorption over a bandwidth of few nanometers (over the visible and ...near-infrared ranges) with a 40-fold increase of the monolayer graphene absorption. We analyze the influence of the geometrical parameters on the absorption rate and the angular response for oblique incidence. Finally, we experimentally verify the theoretical predictions in a one-dimensional, dielectric grating by placing it near either a metallic or a dielectric mirror, thus achieving very good agreement between numerical predictions and experimental results.
Background The learning curve for surgery—i.e., improvement in surgical outcomes with increasing surgeon experience—remains primarily a theoretical concept; actual curves based on surgical outcome ...data are rarely presented. We analyzed the surgical learning curve for prostate cancer recurrence after radical prostatectomy. Methods The study cohort included 7765 prostate cancer patients who were treated with radical prostatectomy by one of 72 surgeons at four major US academic medical centers between 1987 and 2003. For each patient, surgeon experience was coded as the total number of radical prostatectomies performed by the surgeon before the patient’s operation. Multivariable survival–time regression models were used to evaluate the association between surgeon experience and prostate cancer recurrence, defined as a serum prostate-specific antigen (PSA) of more than 0.4 ng/mL followed by a subsequent higher PSA level (i.e., biochemical recurrence), with adjustment for established clinical and tumor characteristics. All P values are two-sided. Results The learning curve for prostate cancer recurrence after radical prostatectomy was steep and did not start to plateau until a surgeon had completed approximately 250 prior operations. The predicted probabilities of recurrence at 5 years were 17.9% (95% confidence interval CI = 12.1% to 25.6%) for patients treated by surgeons with 10 prior operations and 10.7% (95% CI = 7.1% to 15.9%) for patients treated by surgeons with 250 prior operations (difference = 7.2%, 95% CI = 4.6% to 10.1%; P<.001). This finding was robust to sensitivity analysis; in particular, the results were unaffected if we restricted the sample to patients treated after 1995, when stage migration related to the advent of PSA screening appeared largely complete. Conclusions As a surgeon's experience increases, cancer control after radical prostatectomy improves, presumably because of improved surgical technique. Further research is needed to examine the specific techniques used by experienced surgeons that are associated with improved outcomes.
Summary
Background : Prospective trials support the role of capsule enteroscopy as an improvement in diagnosing mucosal lesions in the small bowel.
Aim : To determine the diagnostic yield and safety ...of capsule enteroscopy vs. alternative diagnostic modalities (such as push enteroscopy, small bowel follow‐through or enteroclysis) in patients with small bowel diseases.
Methods : A search for prospective studies comparing capsule enteroscopy vs. other diagnostic tests in adults was performed between 1966 and 2005. Selected articles were included in a meta‐analysis. Three analyses were run separately, all included studies and studies having occult gastrointestinal bleeding or Crohn's disease as main outcome.
Results : Seventeen studies (526 patients) met inclusion criteria. The rate difference (i.e. the absolute pooled difference in the rate of positive findings) between capsule enteroscopy and alternative modalities for small bowel disease was 41% (95% CI 35.6–45.9); 37% (95% CI 29.6–44.1) for occult gastrointestinal bleeding; and 45% (95% CI 30.9–58.0) for Crohn's disease. Failure to visualize the caecum occurred in 13%, significantly more often in occult bleeders (17%) than in patients with Crohn's disease (8%) (P < 0.006). Adverse events were recorded in 29 patients (6%). Capsule retention was more frequent in patients with Crohn's disease (3% vs. 1%, OR 4.37).
Conclusions : Capsule enteroscopy proved significantly superior to push enteroscopy and small bowel radiology in the diagnosis of ileal diseases. Capsule enteroscopy is safe, though prior radiology is still necessary to rule out small bowel strictures in patients with known or suspected Crohn's disease.
ABSTRACT We present the second realization of the International Celestial Reference Frame (ICRF2) at radio wavelengths using nearly 30 years of Very Long Baseline Interferometry observations. ICRF2 ...contains precise positions of 3414 compact radio astronomical objects and has a positional noise floor of ∼40 as and a directional stability of the frame axes of ∼10 as. A set of 295 new "defining" sources was selected on the basis of positional stability and the lack of extensive intrinsic source structure. The positional stability of these 295 defining sources and their more uniform sky distribution eliminates the two greatest weaknesses of the first realization of the International Celestial Reference Frame (ICRF1). Alignment of ICRF2 with the International Celestial Reference System was made using 138 positionally stable sources common to both ICRF2 and ICRF1. The resulting ICRF2 was adopted by the International Astronomical Union as the new fundamental celestial reference frame, replacing ICRF1 as of 2010 January 1.
It is not clear how spontaneous DNA double-strand breaks (DSBs) form and are processed in normal cells, and whether they predispose to cancer-associated translocations. We show that DSBs in normal ...mammary cells form upon release of paused RNA polymerase II (Pol II) at promoters, 5' splice sites and active enhancers, and are processed by end-joining in the absence of a canonical DNA-damage response. Logistic and causal-association models showed that Pol II pausing at long genes is the main predictor and determinant of DSBs. Damaged introns with paused Pol II-pS5, TOP2B and XRCC4 are enriched in translocation breakpoints, and map at topologically associating domain boundary-flanking regions showing high interaction frequencies with distal loci. Thus, in unperturbed growth conditions, release of paused Pol II at specific loci and chromatin territories favors DSB formation, leading to chromosomal translocations.
Abstract Background In patients with myocardial infarction (MI), leaflet tethering by displaced papillary muscles induces mitral regurgitation (MR), which doubles mortality. Mitral valves (MVs) are ...larger in such patients but fibrosis sets in counterproductively. The investigators previously reported that experimental tethering alone increases mitral valve area in association with endothelial-to-mesenchymal transition. Objectives The aim of this study was to explore the clinically relevant situation of tethering and MI, testing the hypothesis that ischemic milieu modifies mitral valve adaptation. Methods Twenty-three adult sheep were examined. Under cardiopulmonary bypass, the papillary muscle tips in 6 sheep were retracted apically to replicate tethering, short of producing MR (tethered alone). Papillary muscle retraction was combined with apical MI created by coronary ligation in another 6 sheep (tethered plus MI), and left ventricular remodeling was limited by external constraint in 5 additional sheep (left ventricular constraint). Six sham-operated sheep were control subjects. Diastolic mitral valve surface area was quantified by 3-dimensional echocardiography at baseline and after 58 ± 5 days, followed by histopathology and flow cytometry of excised leaflets. Results Tethered plus MI leaflets were markedly thicker than tethered-alone valves and sham control subjects. Leaflet area also increased significantly. Endothelial-to-mesenchymal transition, detected as α-smooth muscle actin-positive endothelial cells, significantly exceeded that in tethered-alone and control valves. Transforming growth factor-β, matrix metalloproteinase expression, and cellular proliferation were markedly increased. Uniquely, tethering plus MI showed endothelial activation with vascular adhesion molecule expression, neovascularization, and cells positive for CD45, considered a hematopoietic cell marker. Tethered plus MI findings were comparable with external ventricular constraint. Conclusions MI altered leaflet adaptation, including a profibrotic increase in valvular cell activation, CD45-positive cells, and matrix turnover. Understanding cellular and molecular mechanisms underlying leaflet adaptation and fibrosis could yield new therapeutic opportunities for reducing ischemic MR.
We propose an innovative approach for the realization of a microwave absorber fully transparent in the optical regime. This device is based on the Salisbury screen configuration, which consists of a ...lossless spacer, sandwiched between two graphene sheets whose sheet resistances are different and properly engineered. Experimental results show that it is possible to achieve near-perfect electromagnetic absorption in the microwave X-band. These findings are fully supported by an analytical approach based on an equivalent circuital model. Engineering and integration of graphene sheets could facilitate the realization of innovative microwave absorbers with additional electromagnetic and optical functionalities that could circumvent some of the major limitations of opaque microwave absorbers.
Bacterial spot is a disease that affects tomato worldwide reducing its yield and quality. It is caused by different
Xanthomonas
spp., among which is
Xanthomonas vesicatoria
. Copper-based ...bactericides are generally used to control this disease, although nowadays sustainable strategies are being searched to efficiently replace their use. Our aim was to select native bacteria from tomato rhizosphere with biocontrol properties against
X. vesicatoria
. We selected, characterized, and identified three novel strains, two closely related to
Bacillus velezensis
(VMA11p and VM05) and one closely related to
Pseudomonas soli
(VMAP1), that in vitro antagonized
X. vesicatoria.
We evaluated the efficacy of the three rhizobacteria and their cell-free supernatants to control bacterial spot using the model tomato-
X. vesicatoria
in plants grown in pots, in greenhouse conditions. Bacterial suspensions of VMA11p and VMAP1, applied to the soil by irrigation, significantly (
P
< 0.05) reduced bacterial spot severity by 53.9% and 44.2%, respectively. Nevertheless, the most effective strategy to control bacterial spot was achieved using the cell-free supernatant produced by VMA11p, VM05 or VMAP1 applied as foliar spray, which significantly (
P
< 0.05) reduced the severity of the disease by 98.5%, 94.2% and 75.2%, respectively. None of the treatments reduced the growth of tomato plants. Our results suggest that the use of these novel strains of
Bacillus
and
Pseudomonas
and/or their metabolic products could be used for the development of biocontrol strategies for the management of bacterial spot in tomato.
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