Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun.

High brightness, high charge electron beams are critical for a number of advanced accelerator applications. The initial emittance of the electron beam, which is determined by the mean transverse energy (MTE) and laser spot size, is one of the most important parameters determining the beam quality. The bialkali photocathodes illuminated by a visible laser have the advantages of high quantum efficiency (QE) and low MTE. Furthermore, Superconducting Radio Frequency (SRF) guns can operate in the continuous wave (CW) mode at high accelerating gradients, e.g. with significant reduction of the laser spot size at the photocathode. Combining the bialkali photocathode with the SRF gun enables generation of high charge, high brightness, and possibly high average current electron beams. However, integrating the high QE semiconductor photocathode into the SRF guns has been challenging. In this article, we report on the development of bialkali photocathodes for successful operation in the SRF gun with months-long lifetime while delivering CW beams with nano-coulomb charge per bunch. This achievement opens a new era for high charge, high brightness CW electron beams.

High-Brightness Continuous-Wave Electron Beams from Superconducting Radio-Frequency Photoemission Gun.

Continuous-wave photoinjectors operating at high accelerating gradients promise to revolutionize many areas of science and applications. They can establish the basis for a new generation of monochromatic x-ray free electron lasers, high-brightness hadron beams, or a new generation of microchip production. In this Letter we report on the record-performing superconducting rf electron gun with CsK_{2}Sb photocathode. The gun is generating high charge electron bunches (up to 10 nC/bunch) and low transverse emittances, while operating for months with a single photocathode. This achievement opens a new era in generating high-power beams with a very high average brightness.

Design of a high-bunch-charge 112-MHz superconducting RF photoemission electron source.

High-bunch-charge photoemission electron-sources operating in a continuous wave (CW) mode are required for many advanced applications of particle accelerators, such as electron coolers for hadron beams, electron-ion colliders, and free-electron lasers. Superconducting RF (SRF) has several advantages over other electron-gun technologies in CW mode as it offers higher acceleration rate and potentially can generate higher bunch charges and average beam currents. A 112 MHz SRF electron photoinjector (gun) was developed at Brookhaven National Laboratory to produce high-brightness and high-bunch-charge bunches for the coherent electron cooling proof-of-principle experiment. The gun utilizes a quarter-wave resonator geometry for assuring beam dynamics and uses high quantum efficiency multi-alkali photocathodes for generating electrons.

Blood pressure changes after renal denervation at 10 European expert centers.

We did a subject-level meta-analysis of the changes (Δ) in blood pressure (BP) observed 3 and 6 months after renal denervation (RDN) at 10 European centers. Recruited patients (n=109; 46.8% women; mean age 58.2 years) had essential hypertension confirmed by ambulatory BP. From baseline to 6 months, treatment score declined slightly from 4.7 to 4.4 drugs per day. Systolic/diastolic BP fell by 17.6/7.1 mm Hg for office BP, and by 5.9/3.5, 6.2/3.4, and 4.4/2.5 mm Hg for 24-h, daytime and nighttime BP (P0.03 for all). In 47 patients with 3- and 6-month ambulatory measurements, systolic BP did not change between these two time points (P0.08). Normalization was a systolic BP of <140 mm Hg on office measurement or <130 mm Hg on 24-h monitoring and improvement was a fall of 10 mm Hg, irrespective of measurement technique. For office BP, at 6 months, normalization, improvement or no decrease occurred in 22.9, 59.6 and 22.9% of patients, respectively; for 24-h BP, these proportions were 14.7, 31.2 and 34.9%, respectively. Higher baseline BP predicted greater BP fall at follow-up; higher baseline serum creatinine was associated with lower probability of improvement of 24-h BP (odds ratio for 20-µmol l(-1) increase, 0.60; P=0.05) and higher probability of experiencing no BP decrease (OR, 1.66; P=0.01). In conclusion, BP responses to RDN include regression-to-the-mean and remain to be consolidated in randomized trials based on ambulatory BP monitoring. For now, RDN should remain the last resort in patients in whom all other ways to control BP failed, and it must be cautiously used in patients with renal impairment.

A novel mating approach for genetic algorithms.

Genetic algorithms typically use crossover, which relies on mating a set of selected parents. As part of crossover, random mating is often carried out. A novel approach to parent mating is presented in this work. Our novel approach can be applied in combination with a traditional similarity-based criterion to measure distance between individuals or with a fitness-based criterion. We introduce a parameter called the mating index that allows different mating strategies to be developed within a uniform framework: an exploitative strategy called best-first, an explorative strategy called best-last, and an adaptive strategy called self-adaptive. Self-adaptive mating is defined in the context of the novel algorithm, and aims to achieve a balance between exploitation and exploration in a domain-independent manner. The present work formally defines the novel mating approach, analyzes its behavior, and conducts an extensive experimental study to quantitatively determine its benefits. In the domain of real function optimization, the experiments show that, as the degree of multimodality of the function at hand grows, increasing the mating index improves performance. In the case of the self-adaptive mating strategy, the experiments give strong results for several case studies.

Activation of peripheral kappa/delta opioid receptors mediates 15-deoxy-(Delta12,14)-prostaglandin J2 induced-antinociception in rat temporomandibular joint.

This study assessed the effect of the agonist 15d-PGJ(2) administered into the rat temporomandibular joint (TMJ) on nociceptive behavioral and the anti-inflammatory potential of this prostaglandin on TMJ. It was observed that 15-deoxy-(Delta12,14)-prostaglandin J(2) (15d-PGJ(2)) significantly reduced formalin-induced nociceptive behavior in a dose dependent manner, however injection of 15d-PGJ(2) into the contralateral TMJ failed to reduce such effects. This antinociceptive effect is dependent on peroxisome proliferator-activated receptors-gamma (PPAR-gamma) since pre-treatment with GW9662 (PPAR-gamma receptor antagonist) blocked the antinociceptive effect of 15d-PGJ(2) in the TMJ. In addition, the antinociceptive effect of 15d-PGJ(2) was also blocked by naloxone suggesting the involvement of peripheral opioids in the process. Confirming this hypothesis pre-treatment with kappa, delta, but not mu receptor antagonists significantly reduced the antinociceptive effect of 15d-PGJ(2) in the TMJ. Similarly to opioid agonists, the 15d-PGJ(2) antinociceptive action depends on the nitric oxide (NO)/guanilate cyclase (cGMP)/ATP-sensitive potassium channel blocker(K(+)(ATP)) channel pathway since it was prevented by the pre-treatment with the inhibitors of nitric oxide synthase (NOS; aminoguanidine), cGMP (ODQ), or the K(+)(ATP) (glibenclamide). In addition, 15d-PGJ(2) (100 ng/TMJ) inhibits 5-HT-induced TMJ hypernociception. Besides, TMJ treated with 15d-PGJ(2) showed lower vascular permeability, assessed by Evan's Blue extravasation, and also lower neutrophil migration induced by carrageenan administration. Taken together, these results demonstrate that 15d-PGJ(2) has a potential peripheral antinociceptive and anti-inflammatory effect in the TMJ via PPAR-gamma activation. The results also suggest that 15d-PGJ(2) induced-peripheral antinociceptive response in the TMJ is mediated by kappa/delta opioid receptors by the activation of the intracellular l-arginine/NO/cGMP/K(+)(ATP) channel pathway. The pharmacological properties of the peripheral administration of 15d-PGJ(2) highlight the potential use of this PPAR-gamma agonist on TMJ inflammatory pain conditions.

Constraint handling using tournament selection: abductive inference in partly deterministic bayesian networks.

Constraints occur in many application areas of interest to evolutionary computation. The area considered here is Bayesian networks (BNs), which is a probability-based method for representing and reasoning with uncertain knowledge. This work deals with constraints in BNs and investigates how tournament selection can be adapted to better process such constraints in the context of abductive inference. Abductive inference in BNs consists of finding the most probable explanation given some evidence. Since exact abductive inference is NP-hard, several approximate approaches to this inference task have been developed. One of them applies evolutionary techniques in order to find optimal or close-to-optimal explanations. A problem with the traditional evolutionary approach is this: As the number of constraints determined by the zeros in the conditional probability tables grows, performance deteriorates because the number of explanations whose probability is greater than zero decreases. To minimize this problem, this paper presents and analyzes a new evolutionary approach to abductive inference in BNs. By considering abductive inference as a constraint optimization problem, the novel approach improves performance dramatically when a BN's conditional probability tables contain a significant number of zeros. Experimental results are presented comparing the performances of the traditional evolutionary approach and the approach introduced in this work. The results show that the new approach significantly outperforms the traditional one.

Operational stochastic cooling in the relativistic heavy-ion collider.

Operational stochastic cooling of 100 GeV/nucleon gold beams has been achieved in the BNL Relativistic Heavy-Ion Collider. We discuss the physics and technology of the longitudinal cooling system and present results with the beams. A simulation algorithm is described and shown to accurately model the system.

Thioglycolic acid grafted onto silica gel and its properties in relation to extracting cations from ethanolic solution determined by calorimetric technique.

Thioglycolic acid was immobilized onto silica gel surface using 3-aminopropyltrimethoxysilane as precursor silylating agent to yield silica. The amount of thioglycolic acid immobilized was 1.03 mmol per gram of silica. This new surface displayed a chelating moiety containing nitrogen, sulfur, and oxygen basic centers which are potentially capable of extracting cations from ethanolic solution, such as MCl3 ( M=Fe, Cr, and Mo). This process of extraction was carried out by the batch method when similar chemisorption isotherms were observed for all cations. The data were adjusted to a modified Langmuir equation. The sequence of the maximum retention capacity was Cr(III) > Mo(III) > Fe(III). The same adsorption was determined by calorimetric titration and the enthalpic values of -35.75 +/- 0.02, 32.90 +/- 0.15, and -84.08 +/- 0.12 kJmol(-1) for chromium, molybdenum, and iron, respectively, were obtained. From the calculated Gibbs free energy -23.4 +/- 0.2, -27.2 +/- 0.2, and -32.7 +/- 0.3 kJmol(-1), the variations in entropy obtained were 42 +/- 1, 201 +/- 1, 172 +/- 1 JK(-1)mol(-1) for the same sequence. All thermodynamic values are in agreement with the spontaneity of the proposed cation-basic center interactions for these chelating processes.

Silica gel containing sulfur, nitrogen and oxygen as adsorbent centers on surface for removing copper from aqueous/ethanolic solutions.

Silica gel was modified firstly with aminepropyltrimethoxisilane obtaining the matrix named as SILNH(2). The SILNH(2) silica reacted subsequently with thioglycolic acid Sil-Ntga. The elemental analysis showed the presence of 0.98mmolg(-1) of organic moieties immobilized on silica. Infrared and (13)C NMR spectroscopic data in conjunction with thermogravimetric measurements are in agreement with the suggested functionalization. The ion adsorption properties of the silica Sil-Ntga were studied using copper ions in aqueous/ethanolic solutions in concentrations ranging from 4.0x10(-3) to 5.0x10(-2)moldm(-3) at different temperatures. The new modified silica showed a good sorption ability for copper at lower temperatures and its reuse capacity was demonstrated.

New thiol adsorbent grafted on silica gel: synthesis, characterization and employment for heavy metal adsorptions.

Silica gel surface has been modified in two reaction steps: (i) the silylating agent 3-mercaptopropyltrimetoxysilane was firstly immobilized to give a surface Sil-SH and (ii) this precursor incorporated an ethylene sulfide molecule to obtain the surface denoted Sil-SSH. This material was characterized by elemental analysis, IR spectroscopy, thermogravimetry, solid state 13C and 29Si NMR, and surface area measurement. These materials were employed as adsorbents for divalent heavy cations from aqueous solutions at room temperature and the isotherms were adjusted to a modified Langmuir equation. The maxima number of moles adsorbed were 1.0, 1.5, 1.6, 2.2, 2.4 and 3.3 mmol g(-1) for Co, Cu, Ni, Cd, Pb, and Hg, respectively.

Chemisorption and thermodynamic data of the interaction between a chelate free acidic center with basic groups attached to grafted silicas.

The molecule 2-aminoethanethiol was added to the grafted silylant agent [(3-chlorosilylpropyl)trimethoxysilane] (cpts) onto silica gel(triple bond SilCl), obtaining a surface (triple bond SilSNH(2)) and giving 0.70 mmol g(-1) of nitrogen; the surface of silica was modified with [(3-mercaptosilylpropyl)trimethoxysilane] (mpts) with surface (triple bond SilSH), giving 0.78 mmol g(-1) of sulphur. Both matrices, (triple bond SilSNH(2)) and (triple bond SilSH), adsorb copper and cobalt acetylacetonates from ethanolic solution. Adsorption, using a batchwise process, showed that copper chelate was the most adsorbed. The interactions between the basic centers attached to organic chains of these modified silicas with the cations in the chelates Me(acac)(2) [M=Cu and Co] were followed through calorimetric titrations. Exothermic enthalpic results were obtained for the triple bond SilSNH(2) matrix. The spontaneity of these systems was reflected in negative free Gibbs energy and positive from entropic values.