Laser-plasma accelerators of only a centimetre's length have produced nearly monoenergetic electron bunches with energy as high as 1 GeV. Scaling these compact accelerators to multi-gigaelectronvolt ...energy would open the prospect of building X-ray free-electron lasers and linear colliders hundreds of times smaller than conventional facilities, but the 1 GeV barrier has so far proven insurmountable. Here, by applying new petawatt laser technology, we produce electron bunches with a spectrum prominently peaked at 2 GeV with only a few per cent energy spread and unprecedented sub-milliradian divergence. Petawatt pulses inject ambient plasma electrons into the laser-driven accelerator at much lower density than was previously possible, thereby overcoming the principal physical barriers to multi-gigaelectronvolt acceleration: dephasing between laser-driven wake and accelerating electrons and laser pulse erosion. Simulations indicate that with improvements in the laser-pulse focus quality, acceleration to nearly 10 GeV should be possible with the available pulse energy.
The Oset and Vicente-Vacas model for π N --> π πN reaction has ben used to derive
theoretical values of the amplitudes and cross sections for the π - 2π reaction channels.
It is shown that the N* --> ...N(π π)s—wave mechanism is required in order to obtain
agreement with the world data for the π-ρ --> π-π+ and π-ρ ---> π0 π0 n channels. The
x2 analyses of the world data near threshold for all the channels strongly support the
Weinberg's value of Ƹ = 0 for the chiral symmetry breaking parameter. The value of
C, the factor related to N*Nπ π coupling through the exchange of the scalar meson ε,
was estimated to be C = (-1.97 + 0.11) μ-1.
Background The role of routine central lymph node dissection (CLND) for papillary thyroid cancer (PTC) remains controversial. The aim of this study was to evaluate the impact of routine CLND after ...total thyroidectomy (TTx) in the management of patients with PTC who were clinically node negative at presentation with emphasis on stimulated thyroglobulin (Tg) levels and reoperation rates. Methods This retrospective, multicenter, cohort study used pooled data from 3 international Endocrine Surgery units in Australia, the United States, and England. All study participants had PTC >1 cm without preoperative evidence of lymph node disease (cN0). Group A patients had TTx alone and group B had TTx with the addition of CLND. Results There were 606 patients included in the study. Group A had 347 patients and group B 259 patients. Stimulated Tg values were lower in group B before initial radioiodine ablation (15.0 vs 6.6 ng/mL; P = .025). There was a trend toward a lower Tg at final follow-up in group B (1.9 vs 7.2 ng/mL; P = .11). The rate of reoperation in the central compartment was lower in group B (1.5 vs 6.1%; P = .004). The number of CLND procedures required to prevent 1 central compartment reoperation was calculated at 20. Conclusion The addition of routine CLND in cN0 papillary thyroid carcinoma is associated with lower postoperative Tg levels and reduces the need for reoperation in the central compartment.
A fixed-dose combination therapy (polypill strategy) has been proposed as an approach to reduce the burden of cardiovascular disease, especially in low-income and middle-income countries (LMICs). The ...PolyIran study aimed to assess the effectiveness and safety of a four-component polypill including aspirin, atorvastatin, hydrochlorothiazide, and either enalapril or valsartan for primary and secondary prevention of cardiovascular disease.
The PolyIran study was a two-group, pragmatic, cluster-randomised trial nested within the Golestan Cohort Study (GCS), a cohort study with 50 045 participants aged 40–75 years from the Golestan province in Iran. Clusters (villages) were randomly allocated (1:1) to either a package of non-pharmacological preventive interventions alone (minimal care group) or together with a once-daily polypill tablet (polypill group). Randomisation was stratified by three districts (Gonbad, Aq-Qala, and Kalaleh), with the village as the unit of randomisation. We used a balanced randomisation algorithm, considering block sizes of 20 and balancing for cluster size or natural log of the cluster size (depending on the skewness within strata). Randomisation was done at a fixed point in time (Jan 18, 2011) by statisticians at the University of Birmingham (Birmingham, UK), independent of the local study team. The non-pharmacological preventive interventions (including educational training about healthy lifestyle—eg, healthy diet with low salt, sugar, and fat content, exercise, weight control, and abstinence from smoking and opium) were delivered by the PolyIran field visit team at months 3 and 6, and then every 6 months thereafter. Two formulations of polypill tablet were used in this study. Participants were first prescribed polypill one (hydrochlorothiazide 12·5 mg, aspirin 81 mg, atorvastatin 20 mg, and enalapril 5 mg). Participants who developed cough during follow-up were switched by a trained study physician to polypill two, which included valsartan 40 mg instead of enalapril 5 mg. Participants were followed up for 60 months. The primary outcome—occurrence of major cardiovascular events (including hospitalisation for acute coronary syndrome, fatal myocardial infarction, sudden death, heart failure, coronary artery revascularisation procedures, and non-fatal and fatal stroke)—was centrally assessed by the GCS follow-up team, who were masked to allocation status. We did intention-to-treat analyses by including all participants who met eligibility criteria in the two study groups. The trial was registered with ClinicalTrials.gov, number NCT01271985.
Between Feb 22, 2011, and April 15, 2013, we enrolled 6838 individuals into the study—3417 (in 116 clusters) in the minimal care group and 3421 (in 120 clusters) in the polypill group. 1761 (51·5%) of 3421 participants in the polypill group were women, as were 1679 (49·1%) of 3417 participants in the minimal care group. Median adherence to polypill tablets was 80·5% (IQR 48·5–92·2). During follow-up, 301 (8·8%) of 3417 participants in the minimal care group had major cardiovascular events compared with 202 (5·9%) of 3421 participants in the polypill group (adjusted hazard ratio HR 0·66, 95% CI 0·55–0·80). We found no statistically significant interaction with the presence (HR 0·61, 95% CI 0·49–0·75) or absence of pre-existing cardiovascular disease (0·80; 0·51–1·12; pinteraction=0·19). When restricted to participants in the polypill group with high adherence, the reduction in the risk of major cardiovascular events was even greater compared with the minimal care group (adjusted HR 0·43, 95% CI 0·33–0·55). The frequency of adverse events was similar between the two study groups. 21 intracranial haemorrhages were reported during the 5 years of follow-up—ten participants in the polypill group and 11 participants in the minimal care group. There were 13 physician-confirmed diagnoses of upper gastrointestinal bleeding in the polypill group and nine in the minimal care group.
Use of polypill was effective in preventing major cardiovascular events. Medication adherence was high and adverse event numbers were low. The polypill strategy could be considered as an additional effective component in controlling cardiovascular diseases, especially in LMICs.
Tehran University of Medical Sciences, Barakat Foundation, and Alborz Darou.
BACKGROUND:
Several studies have reported the incidence, morbidity, and mortality of general surgical conditions (GSCs) in orthotopic heart transplant (OHT) patients. The following is the largest ...reported series of such patients and the first study with sufficient patient numbers to formally evaluate peritransplant variables as risk factors for GSC development.
STUDY DESIGN:
A GSC was defined as a condition for which a general surgeon had been consulted or as a general surgical condition recognized at the time of autopsy. The records of 453 consecutive patients who underwent OHT between 1981 and 1999 were reviewed to identify patients who developed a GSC. Kaplan-Meier actuarial analysis on this cohort, and univariate and multivariate logistic regression models applied to a subpopulation of 324 consecutive OHT patients between 1987 and 1997 were used to determine factors associated with and predictive of GSC after OHT.
RESULTS:
Of 453 OHT patients, 371 (81.9%) were men, and the average age was 44.5±15 (standard deviation) years. Median followup was 2,086 days (range 1 to 6,642 days). Ninety-three patients (20.5%) developed 111 GSCs. Of these, 78 were men, and the average age was 49.9±10.2 years. There were 83 general surgical interventions. Actuarial analyses revealed that age greater than 50 years, pretransplant diagnosis of ischemic (PTDxI) versus nonischemic heart disease, and previous general surgical history were factors associated (p<0.05) with a higher GSC incidence. Gender, more urgent transplant priority status, cardiopulmonary bypass time, total graft ischemic time, and intensive care unit length of stay were not associated with GSC. Factors associated with GSC on univariate analysis, with odds ratios (ORs) and 95% confidence intervals (CIs) included: age analyzed as a continuous variable (OR 1.04 per year; CI 1.01, 1.06 per year; p = 0.0021), PTDxI (OR 2.40; CI 1.39, 4.15; p = 0.0016), and pretransplant general surgical history (OR 3.35; CI 1.65, 6.82; p = 0.0008). Multivariate analysis revealed that only pretransplant general surgical history (OR 3.27; CI 1.58, 6.76; p = 0.0004) and PTDxI (OR 2.37; CI 1.35, 4.16; p = 0.0023) were associated with subsequent development of GSC.
CONCLUSIONS:
A pretransplant diagnosis of ischemic heart disease and previous history of a general surgical procedure are two independent risk factors that predispose OHT patients to development of GSC. Because GSC may arise insidiously in immunosuppressed patients, identification of OHT patients at higher risk for GSC will permit timely intervention decisions, decreasing morbidity and mortality in this challenging group of patients.
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