A semi-parametric approach to estimate risk functions associated with multi-dimensional exposure profiles: application to smoking and lung cancer

A common characteristic of environmental epidemiology is the multi-dimensional aspect of exposure patterns, frequently reduced to a cumulative exposure for simplicity of analysis. By adopting a flexible Bayesian clustering approach, we explore the risk function linking exposure history to disease. This approach is applied here to study the relationship between different smoking characteristics and lung cancer in the framework of a population based case control study

The NA48 LKr calorimeter digitizer electronics chain

The 13 500 channels of the NA48 liquid-krypton electromagnetic calorimeter readout electronics were put into operation in 1997. The digitizer electronics employs a new gain switching technique that expands the dynamic range of a standard 10-bit ADC to 14 bits at 40 MHz sampling rate employing a custom-developed integrated circuit (KRYPTON). The KRYPTON has been fabricated in 1.2 μm BiCMOS technology and was successfully developed together with industry on a short timescale. The performance and the experience from the first year of the operation of the liquid-krypton calorimeter electronics will also be briefly discussed

Crown ethers: novel permeability enhancers for ocular drug delivery?

Crown ethers are cyclic molecules consisting of a ring containing several ether groups. The most common and important members of this series are 12-crown-4 (12C4), 15-crown-5 (15C5), and 18-crown-6 (18C6). These container molecules have the ability to sequester metal ions and their complexes with drugs are able to traverse cell membranes. This study investigated 12C4, 15C5 and 18C6 for their ability to increase solubility of ocular drugs and enhance their penetration into the cornea. Phase solubility analysis determined crown ethers’ ability to enhance the solubility of riboflavin, a drug used for the therapy of keratoconus, and these solutions were investigated for ocular drug permeation enhancing properties. Atomic absorption spectroscopy demonstrated crown ether solutions ability to sequester Ca2+ from corneal epithelia and crown ether mediated adsorption of riboflavin into the stroma was investigated. Induced corneal opacity studies assessed potential toxicity of crown ethers. Crown ethers enhanced riboflavin’s aqueous solubility and its penetration into in vitro bovine corneas; the smaller sized crown ethers gave greatest enhancement. They were shown to sequester Ca2+ ions from corneal epithelia, doing so loosens cellular membrane tight junctions thus enhancing riboflavin penetration. Induced corneal opacity was similar to that afforded by benzalkonium chloride and less than is produced using polyaminocarboxylic acids. However, in vivo experiments performed in rats with 12C4 did not show any statistically significant permeability enhancement compared to enhancer-free formulation

First observation of the KS->pi0 gamma gamma decay

Using the NA48 detector at the CERN SPS, 31 KS->pi0 gamma gamma candidates with an estimated background of 13.7 +- 3.2 events have been observed. This first observation leads to a branching ratio of BR(KS->pi0 gamma gamma) = (4.9 +- 1.6(stat) +- 0.9(syst)) x 10^-8 in agreement with Chiral Perturbation theory predictions.Comment: 10 pages, 4 figures submitted to Phys. Lett.

Search for CP violation in K0 -> 3 pi0 decays

Using data taken during the year 2000 with the NA48 detector at the CERN SPS, a search for the CP violating decay K_S -> 3 pi0 has been performed. From a fit to the lifetime distribution of about 4.9 million reconstructed K0/K0bar -> 3 pi0 decays, the CP violating amplitude eta_000 = A(K_S -> 3 pi0)/A(K_L -> 3 pi0) has been found to be Re(eta_000) = -0.002 +- 0.011 +- 0.015 and Im(eta_000) = -0.003 +- 0.013 +- 0.017. This corresponds to an upper limit on the branching fraction of Br(K_S -> 3 pi0) < 7.4 x 10^-7 at 90% confidence level. The result is used to improve knowledge of Re(epsilon) and the CPT violating quantity Im(delta) via the Bell-Steinberger relation.Comment: 18 pages, 7 figures, submitted to Phys. Lett.

Measurement of the Ratio Gamma(KL -> pi+ pi-)/Gamma(KL -> pi e nu) and Extraction of the CP Violation Parameter |eta+-|

We present a measurement of the ratio of the decay rates Gamma(KL -> pi+ pi-)/Gamma(KL -> pi e nu), denoted as Gamma(K2pi)/Gamma(Ke3). The analysis is based on data taken during a dedicated run in 1999 by the NA48 experiment at the CERN SPS. Using a sample of 47000 K2pi and five million Ke3 decays, we find Gamma(K2pi)/Gamma(Ke3) = (4.835 +- 0.022(stat) +- 0.016(syst)) x 10^-3. From this we derive the branching ratio of the CP violating decay KL -> pi+ pi- and the CP violation parameter |eta+-|. Excluding the CP conserving direct photon emission component KL -> pi+ pi- gamma, we obtain the results BR(KL -> pi+ pi-) = (1.941 +- 0.019) x 10^-3 and |eta+-| = (2.223 +- 0.012) x 10^-3.Comment: 20 pages, 7 figures, accepted by Phys. Lett.

Measurement of the branching ratio of the decay KL -> pi e nu and extraction of the CKM parameter |Vus|

We present a new measurement of the branching ratio R of the decay KL -> pi e nu (Ke3), relative to all charged KL decays with two tracks, based on data taken with the NA48 detector at the CERN SPS. We measure R = 0.4978 +- 0.0035. From this we derive the Ke3 branching fraction and the weak coupling parameter |Vus| in the CKM matrix. We obtain |Vus|f+(0) = 0.2146 +- 0.0016, where f+(0) is the vector form factor in the Ke3 decay.Comment: 18 pages, 8 figures. accepted by Phys Lett.

Measurement of K^0_e3 form factors

The semileptonic decay of the neutral K meson, KL -> pi e nu (Ke3), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f_+(q^2)), scalar (f_S) and tensor (f_T) interactions were measured. The linear slope of the vector form factor lambda_+ = 0.0284+-0.0007+-0.0013 and values for the ratios |f_S/f_+(0)| = 0.015^{+0.007}_{-0.010}+-0.012 and |f_T/f_+(0)| = 0.05^{+0.03}_{-0.04}+-0.03 were obtained. The values for f_S and f_T are consistent with zero. Assuming only Vector-Axial vector couplings, lambda_+ = 0.0288+-0.0004+-0.0011 and a good fit consistent with pure V-A couplings were obtained. Alternatively, a fit to a dipole form factor yields a pole mass of M = 859+-18 MeV, consistent with the K^*(892) mass.Comment: 16 pages, 7 figures. submitted to Phys. Lett.