Narrow Results

The following topics are under this section:

• ASIA-PACIFIC — Collaborative research effort reveals chemical compound that kills drug-resistant bacteria
• ASIA-PACIFIC — Big Data Analytics used for Personalized Assessment Tool for Cancer Diagnosis
• ASIA-PACIFIC — Identifying the Molecular Mechanisms of Creating a Memory
• ASIA-PACIFIC — Funding for New Stem Cell Research provides Hope for Premature Born Babies
• ASIA-PACIFIC — Human Cortical Organoids used to Identify Mechanisms behind Epilepsy in Angelman Syndrome
• ASIA-PACIFIC — The Future of Contact Lenses: Self-Moisturising Technology
• ASIA-PACIFIC — Glycosylation of Protein Structure on Virus provide Insight to Molecular Understanding
• ASIA-PACIFIC — Comprehensive Mapping of the Human Brain using Synchrotron X-rays
• REST OF THE WORLD — Uncovering New Tricks for Old Drugs
• REST OF THE WORLD — Combination of Prenatal Smoking and Drinking adds on to Risk of SIDS
• REST OF THE WORLD — Blood Pressure Readings Could Provide Valuable Information on Early Warning Signs of Heart Disease
• REST OF THE WORLD — Study finds Households in the United States Wastes nearly a Third of the Food they Buy

Major investments in science and technology are designed to generate something beyond the science itself. Government-funded big science infrastructure, exemplified by the Canadian Light Source Synchrotron (CLS), offers places for scientists both to conduct their scientific investigations and to do things that more directly add economic and social value. Scientists, however, do not work in isolation. They are usually part of larger networks or communities that can generate bigger net effects for the affiliated individuals and institutions. Understanding the structure and scale of these scientific networks provides insights into the impacts of big science on the scientific community (locally and globally) and the potential opportunities that may be realised. This study applies the social network analysis (SNA) methodology and combines it with a survey and statistical analysis to assess the network of scholars attached to the CLS, to explore the evolution of collaborative behaviour over time and to explore the relationships between the network and specific output and outcome variables. The study concludes that the CLS has generated a large and growing scholarly community; at the core of the network is a group of highly linked and engaged scholars who have the aptitude and experience to extend their research results into application and use.

About 80 years ago Rutherford [1] expressed the hope that particles could be accelerated to energies exceeding those occurring in radioactivity, enabling the study of nuclei and their constituents. Physicists and engineers have more than met this challenge, and today the LHC (Large Hadron Collider) at CERN, Geneva is about to accelerate protons to 7 trillion (7 × 10¹²) eV. Here we describe some of the crucial steps that have gotten us there.

The world's first hospital-based proton treatment center opened at Loma Linda University Medical Center in 1990, following two decades of development. Patients' needs were the driving force behind its conception, development, and execution; the primary needs were delivery of effective conformal doses of ionizing radiation and avoidance of normal tissue to the maximum extent possible. The facility includes a proton synchrotron and delivery system developed in collaboration with physicists and engineers at Fermi National Accelerator Laboratory and from other high-energy-physics laboratories worldwide. The system, operated and maintained by Loma Linda personnel, was designed to be safe, reliable, flexible in utilization, efficient in use, and upgradeable to meet demands of changing patient needs and advances in technology. Since the facility opened, nearly 14,000 adults and children have been treated for a wide range of cancers and other diseases. Ongoing research is expanding the applications of proton therapy, while reducing costs.

An overview is given of different techniques of dose delivery applied in currently operating and planned particle therapy systems. Their advantages and disadvantages will be compared and consequences of the methods for the rest of the instrumentation will be discussed. The interrelationship between beam delivery at the patient and the accelerator system is shown by means of several concrete examples. Apart from a description of several subsystems in a particle therapy facility, design rules for optimizing the reliability of an accelerator and beam delivery system will be discussed, as well as some remarks concerning how to deal with future developments.

Since 1990, when the world's first hospital-based proton therapy center opened in Loma Linda, California, interest in dedicated proton and carbon ion therapy facilities has been growing steadily. Today, many proton therapy centers are in operation, but the number of centers offering carbon ion therapy is still very low. This difference reflects the fact that protons are well accepted by the medical community, whereas radiotherapy with carbon ions is still experimental. Furthermore, accelerators for carbon ions are larger, more complicated and more expensive than those for protons only. This article describes the accelerator performance required for hadrontherapy and how this is realized, with particular emphasis on carbon ion synchrotrons.

In the last five decades, proton–proton and proton–antiproton colliders have been the most powerful tools for high energy physics investigations. They have also deeply catalyzed innovation in accelerator physics and technology. Among the large number of proposed colliders, only four have really succeeded in becoming operational: the ISR, the SppbarS, the Tevatron and the LHC. Another hadron collider, RHIC, originally conceived for ion–ion collisions, has also been operated part-time with polarized protons. Although a vast literature documenting them is available, this paper is intended to provide a quick synthesis of their main features and key performance.

Ceramics of the composition BaBiO₃ (BB) were sintered in oxygen to obtain a single phase with monoclinic $I$2/$m$ symmetry as suggested by high-resolution X-ray diffraction. X-ray photoelectron spectroscopy confirmed the presence of bismuth in two valence states — 3$+$ and 5$+$. Optical spectroscopy showed presence of a direct bandgap at $\sim$ 2.2eV and a possible indirect bandgap at $\sim$ 0.9eV. This combined with determination of the activation energy for conduction of 0.25eV, as obtained from ac impedance spectroscopy, suggested that a polaron-mediated conduction mechanism was prevalent in BB. The BB ceramics were crushed, mixed with BaTiO₃ (BT), and sintered to obtain BT–BB solid solutions. All the ceramics had tetragonal symmetry and exhibited a normal ferroelectric-like dielectric response. Using ac impedance and optical spectroscopy, it was shown that resistivity values of BT–BB were orders of magnitude higher than BT or BB alone, indicating a change in the fundamental defect equilibrium conditions. A shift in the site occupancy of Bi to the A-site is proposed to be the mechanism for the increased electrical resistivity.

We investigate automatic γ-ray photon quenching in compact non-thermal sources. This is an auto-regulating network of processes that consists of photon-photon absorption and synchrotron emission of the produced e^- e⁺ pairs and operates non linearly whenever the γ-ray luminosity exceeds a critical value. We present expressions for this quantity and discuss our results.

About 80 years ago Rutherford [1] expressed the hope that particles could be accelerated to energies exceeding those occurring in radioactivity, enabling the study of nuclei and their constituents. Physicists and engineers have more than met this challenge, and today the LHC (Large Hadron Collider) at CERN, Geneva is about to accelerate protons to 7 trillion (7 × 10¹²) eV. Here we describe some of the crucial steps that have gotten us there.

Many present and future storage-ring-based light sources make use of cavities at a harmonic of the main RF to lengthen the electron bunches. This reduces Touschek and intrabeam scattering to improve the beam lifetime and transverse emittances respectively. These harmonic cavities are also beneficial in increasing the threshold currents of many collective instabilities in both longitudinal and transverse planes. The latter case has previously been explored in detail making extensive use of Laclare’s eigenvalue method. Such an approach does not take into account the diffusion of head-tail modes of nonzeroth order, which is a consequence of the quantum-mechanical nature of synchrotron radiation. In this paper, we show that Laclare’s eigenvalue method is a change of basis from another popular method of solving the Sacherer formalism, where Fokker-Planck diffusion terms can be readily included. For the case of the MAX IV 3 GeV ring, it is found that the effect is a large increase in the threshold currents of the resistive-wall coupled-bunch instability at positive chromaticity.

The world's first hospital-based proton treatment center opened at Loma Linda University Medical Center in 1990, following two decades of development. Patients' needs were the driving force behind its conception, development, and execution; the primary needs were delivery of effective conformal doses of ionizing radiation and avoidance of normal tissue to the maximum extent possible. The facility includes a proton synchrotron and delivery system developed in collaboration with physicists and engineers at Fermi National Accelerator Laboratory and from other high-energy-physics laboratories worldwide. The system, operated and maintained by Loma Linda personnel, was designed to be safe, reliable, flexible in utilization, efficient in use, and upgradeable to meet demands of changing patient needs and advances in technology. Since the facility opened, nearly 14,000 adults and children have been treated for a wide range of cancers and other diseases. Ongoing research is expanding the applications of proton therapy, while reducing costs.

Since 1990, when the world's first hospital-based proton therapy center opened in Loma Linda, California, interest in dedicated proton and carbon ion therapy facilities has been growing steadily. Today, many proton therapy centers are in operation, but the number of centers offering carbon ion therapy is still very low. This difference reflects the fact that protons are well accepted by the medical community, whereas radiotherapy with carbon ions is still experimental. Furthermore, accelerators for carbon ions are larger, more complicated and more expensive than those for protons only. This article describes the accelerator performance required for hadrontherapy and how this is realized, with particular emphasis on carbon ion synchrotrons.

An overview is given of different techniques of dose delivery applied in currently operating and planned particle therapy systems. Their advantages and disadvantages will be compared and consequences of the methods for the rest of the instrumentation will be discussed. The interrelationship between beam delivery at the patient and the accelerator system is shown by means of several concrete examples. Apart from a description of several subsystems in a particle therapy facility, design rules for optimizing the reliability of an accelerator and beam delivery system will be discussed, as well as some remarks concerning how to deal with future developments.

The polarized ion source at the cooler synchrotron facility COSY of the research center Jülich, Germany, delivers negative polarized proton or deuteron ions for investigation of hadron structure and dynamics in the momentum range from 0.3 GeV/c to 3.8 GeV/c. The polarized negative ion source at COSY is based on the colliding beams principle, using an intense pulsed neutralized cesium beam for charge exchange with a pulsed highly polarized hydrogen or deuterium beam. The source is operated at 0.5 Hz repetition rate with 20 ms pulse length which is the maximum useful length for the stripping injection into the synchrotron. The paper summarizes the status and activities at the polarized ion source at the COoler SYnchrotron COSY/Jülich.

In the last five decades, proton–proton and proton–antiproton colliders have been the most powerful tools for high energy physics investigations. They have also deeply catalyzed innovation in accelerator physics and technology. Among the large number of proposed colliders, only four have really succeeded in becoming operational: the ISR, the SppbarS, the Tevatron and the LHC. Another hadron collider, RHIC, originally conceived for ion–ion collisions, has also been operated part-time with polarized protons. Although a vast literature documenting them is available, this paper is intended to provide a quick synthesis of their main features and key performance.