Rapid Sorption Kinetics THEORETICAL TREATMENT OF RAPID SORPTION KINETICS MEASURED IN BATCH ARRANGEMENT

Universal solution of a family of sorption kinetic models which are based on superposition principle has been developed to describe sorption experiments in a closed system. The models account for the interactions of a sorbate-sorbent system with the apparatus which arise (i) from the mass balance condition in a closed system and (ii) from a finite rate of sorbate supply to the sorbent, the latter effect being of importance particularly in rapid nonstationary kinetic processes. Theoretical uptake curves for the intracrystalline sorption kinetics in zeolite crystals are exemplified using numerical solution of the corresponding Volterra integral equations which represent kinetic models of the overall transient sorption process in the apparatus. The approach appears to be promising for treatment of sorption kinetics in multi component systems. The Volterra Integral Equation (VIE) approach has recently been proposed to solve mathematical models of sorption kinetics from the gas phase measured under constant volume/variable pressure conditions 1. For fast sorption kinetics with characteristic times amounting to about one second, one arrives at the limits of the experimental method and thus, the valve used to start the experiment may distort the uptake curves considerably. In a previous publication 2 , the valve effect was analyzed thoroughly for a special type of sorption kinetics. The use of the VIE approach 1,3,4, offers a general way to compute sorption uptake curves affected by the limited rate of sorbate supply through valves and tubings of the experimental apparatus. In such a manner the limits of the experimental methods can in principle be displaced about one order of magnitude to lower intrinsic time constants of sorption kinetics whatever type of valve may be used. DESCRIPTION OF THE EXPERIMENT The principal scheme of the experimental piezometric apparatus is given i

An Optical Atomic Clock Based on a Highly Charged Ion

Optical atomic clocks are the most accurate measurement devices ever constructed and have found many applications in fundamental science and technology. The use of highly charged ions (HCI) as a new class of references for highest accuracy clocks and precision tests of fundamental physics has long been motivated by their extreme atomic properties and reduced sensitivity to perturbations from external electric and magnetic fields compared to singly charged ions or neutral atoms. Here we present the first realisation of this new class of clocks, based on an optical magnetic-dipole transition in Ar$^{13+}$. Its comprehensively evaluated systematic frequency uncertainty of $2.2\times10^{-17}$ is comparable to that of many optical clocks in operation. From clock comparisons we improve by eight and nine orders of magnitude upon the uncertainties for the absolute transition frequency and isotope shift ($^{40}$Ar vs. $^{36}$Ar), respectively. These measurements allow us to probe the largely unexplored quantum electrodynamic nuclear recoil, presented as part of improved calculations of the isotope shift which reduce the uncertainty of previous theory by a factor of three. This work establishes forbidden optical transitions in HCI as references for cutting-edge optical clocks and future high-sensitivity searches for physics beyond the standard model.Comment: Main: 20 pages, 3 figures. Supplement: 19 pages, 2 figure

Clinical outcome 10 years after attempted percutaneous transluminal coronary angioplasty in 856 patients.

Abstract OBJECTIVES: This study reports the 10-year outcome of 856 consecutive patients who underwent attempted coronary angioplasty at the Thoraxcenter during the years 1980 to 1985. BACKGROUND: Coronary balloon angioplasty was first performed in 1977, and this procedure was introduced into clinical practice at the Thoraxcenter in 1980. Although advances have been made, extending our knowledge of the long-term outcome in terms of survival and major cardiac events remains of interest and a valuable guide in the treatment of patients with coronary artery disease. METHODS: Details of survival, cardiac events, symptoms and medication were retrospectively obtained from the Dutch civil registry, medical records or by letter or telephone or from the patient's physician and entered into a dedicated data base. Patient survival curves were constructed, and factors influencing survival and cardiac events were identified. RESULTS: The procedural clinical success rate was 82%. Follow-up information was obtained in 837 patients (97.8%). Six hundred forty-one patients (77%) were alive, of whom 334 (53%) were symptom free, and 254 (40%) were taking no antianginal medication. The overall 5- and 10-year survival rates were 90% (95% confidence interval [CI] 87.6% to 92.4%) and 78% (95% CI 75.0% to 81.0%), respectively, and the respective freedom from significant cardiac events (death, myocardial infarction, coronary artery bypass surgery and repeat angioplasty) was 57% (95% CI 53.4% to 60.6%) and 36% (95% CI 32.4% to 39.6%). Factors that were found to adversely influence 10-year survival were age > or = 60 years (> or = 60 years [67%], 50 to 59 years [82%], or = 50% [80%]) and a history of previous myocardial infarction (previous myocardial infarction [72%], no previous infarction [83%]). These factors were also found to be independent predictors of death during the follow-up period by a multivariate stepwise logistic regression analysis. Other factors tested, with no influence on survival, were gender, procedural success and stability of angina at the time of intervention. CONCLUSIONS: The long-term prognosis of patients after coronary angioplasty is good, particularly in those <60 years old with single-vessel disease and normal left ventricular function. The majority of patients are likely to experience a further cardiac event in the 10 years after their first angioplasty procedure

Trap-integrated fluorescence detection based on silicon photomultipliers in a cryogenic Penning trap

We present a fluorescence-detection system for laser-cooled 9Be+ ions based on silicon photomultipliers (SiPM) operated at 4 K and integrated into our cryogenic 1.9 T multi-Penning-trap system. Our approach enables fluorescence detection in a hermetically-sealed cryogenic Penning-trap chamber with limited optical access, where state-of-the-art detection using a telescope and photomultipliers at room temperature would be extremely difficult. We characterize the properties of the SiPM in a cryocooler at 4 K, where we measure a dark count rate below 1/s and a detection efficiency of 2.5(3) %. We further discuss the design of our cryogenic fluorescence-detection trap, and analyze the performance of our detection system by fluorescence spectroscopy of 9Be+ ion clouds during several runs of our experiment.Comment: 12 pages, 11 figure

A randomized multi-center phase II trial of the angiogenesis inhibitor Cilengitide (EMD 121974) and gemcitabine compared with gemcitabine alone in advanced unresectable pancreatic cancer

BACKGROUND: Anti-angiogenic treatment is believed to have at least cystostatic effects in highly vascularized tumours like pancreatic cancer. In this study, the treatment effects of the angiogenesis inhibitor Cilengitide and gemcitabine were compared with gemcitabine alone in patients with advanced unresectable pancreatic cancer. METHODS: A multi-national, open-label, controlled, randomized, parallel-group, phase II pilot study was conducted in 20 centers in 7 countries. Cilengitide was administered at 600 mg/m(2 )twice weekly for 4 weeks per cycle and gemcitabine at 1000 mg/m(2 )for 3 weeks followed by a week of rest per cycle. The planned treatment period was 6 four-week cycles. The primary endpoint of the study was overall survival and the secondary endpoints were progression-free survival (PFS), response rate, quality of life (QoL), effects on biological markers of disease (CA 19.9) and angiogenesis (vascular endothelial growth factor and basic fibroblast growth factor), and safety. An ancillary study investigated the pharmacokinetics of both drugs in a subset of patients. RESULTS: Eighty-nine patients were randomized. The median overall survival was 6.7 months for Cilengitide and gemcitabine and 7.7 months for gemcitabine alone. The median PFS times were 3.6 months and 3.8 months, respectively. The overall response rates were 17% and 14%, and the tumor growth control rates were 54% and 56%, respectively. Changes in the levels of CA 19.9 went in line with the clinical course of the disease, but no apparent relationships were seen with the biological markers of angiogenesis. QoL and safety evaluations were comparable between treatment groups. Pharmacokinetic studies showed no influence of gemcitabine on the pharmacokinetic parameters of Cilengitide and vice versa. CONCLUSION: There were no clinically important differences observed regarding efficacy, safety and QoL between the groups. The observations lay in the range of other clinical studies in this setting. The combination regimen was well tolerated with no adverse effects on the safety, tolerability and pharmacokinetics of either agent

Polymorphisms in the selectin gene cluster are associated with fertility and survival time in a population of Holstein Friesian cows

Selectins are adhesion molecules, which mediate attachment between leucocytes and endothelium. They aid extravasation of leucocytes from blood into inflamed tissue during the mammary gland’s response to infection. Selectins are also involved in attachment of the conceptus to the endometrium and subsequent placental development. Poor fertility and udder health are major causes for culling dairy cows. The three identified bovine selectin genes SELP, SELL and SELE are located in a gene cluster. SELP is the most polymorphic of these genes. Several SNP in SELP and SELE are associated with human vascular disease, while SELP SNP rs6127 has been associated with recurrent pregnancy loss in women. This study describes the results of a gene association study for SNP in SELP (n = 5), SELL (n = 2) and SELE (n = 1) with fertility, milk production and longevity traits in a population of 337 Holstein Friesian dairy cows. Blood samples for PCR-RFLP were collected at 6 months of age and animals were monitored until either culling or 2,340 days from birth. Three SNP in SELPEx4-6 formed a haplotype block containing a Glu/Ala substitution at rs42312260. This region was associated with poor fertility and reduced survival times. SELPEx8 (rs378218397) coded for a Val475Met variant locus in the linking region between consensus repeats 4 and 5, which may influence glycosylation. The synonymous SNP rs110045112 in SELEEx14 deviated from Hardy Weinberg equilibrium. For both this SNP and rs378218397 there were too few AA homozygotes present in the population and AG heterozygotes had significantly worse fertility than GG homozygotes. Small changes in milk production associated with some SNP could not account for the reduced fertility and only SELPEx6 showed any association with somatic cell count. These results suggest that polymorphisms in SELP and SELE are associated with the likelihood of successful pregnancy, potentially through compromised implantation and placental development

Quantum Logic Spectroscopy of Highly Charged Ions

Fundamental interactions and symmetries define the structure and properties of all matter, in particular of its small and diverse visible constituents—the atoms. The study of their distinctive spectra through precision spectroscopy is therefore a vital tool to advance our understanding of nature. Highly charged ions (HCIs) constitute the largest fraction of all atoms since every atom has as many charge states as electrons it can bind. Although most of the matter on Earth is neutral, HCIs are ubiquitous in the universe and their systematic study is essential not only for atomic physics but eminently for astrophysics, nuclear physics, and fusion research, among others. Recently, HCIs have been identified as ideal candidates for sensitive tests of physics beyond the Standard Model of particle physics and for use in future high-accuracy optical atomic clocks. However, the realization of such proposals has been hindered by the hitherto constrained laboratory control and limited spectroscopic accuracy of about parts-per-million fractional uncertainty levels. This thesis reports the first coherent laser spectroscopy of HCIs, boosting the achievable spectroscopic precision by eight orders of magnitude compared to traditional spectroscopy methods. The 2P1/2–2P3/2 fine-structure ground-state transition in highly charged 40Ar13+ at an optical wavelength of 441 nm was chosen as a proof-of-principle case. A single ion of this species was isolated from a megakelvin-hot plasma cloud and co-trapped together with a laser-cooled singly charged 9Be+ ion in a two-ion crystal, confined in the harmonic potential of a cryogenic linear Paul trap. This coupled quantum-mechanical system was then cooled to its ground state of axial motion, corresponding to the lowest temperature of a HCI ever achieved. The spectroscopy was realized by implementing quantum logic techniques which allow preparation of the quantum state of the HCI and to map its electronic state after spectroscopy onto the 9Be+ logic ion in order to detect it there with high efficiency through electron shelving. In addition to the increase of spectroscopic precision, the excited-state lifetime and g-factor were measured—the latter one to unprecedented accuracy, resolving effects from special relativity, interelectronic interactions, and quantum electrodynamics. Moreover, it settled a discrepancy between theoretical predictions. The demonstrated techniques are not limited to the specific 40Ar13+ species but universally applicable to other HCIs. Thereby, this work unlocks the potential of HCIs for unrivaled tests of fundamental physics, the search for new physics—such as a 5th force, variations of fundamental constants and dark matter candidates—as well as the use of HCIs in novel optical atomic clocks