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When laser radiation is skilfully applied, atoms and molecules can be cooled1–3, allowing the precise measurements and control of quantum systems. This is essential for the fundamental studies of physics as well as practical applications such as precision spectroscopy4–7, ultracold gases with quantum statistical properties8–10 and quantum computing. In laser cooling, atoms are slowed to otherwise unattainable velocities through repeated cycles of laser photon absorption and spontaneous emission in random directions. Simple systems can serve as rigorous testing grounds for fundamental physics—one such case is the purely leptonic positronium11,12, an exotic atom comprising an electron and its antiparticle, the positron. Laser cooling of positronium, however, has hitherto remained unrealized. Here we demonstrate the one-dimensional laser cooling of positronium. An innovative laser system emitting a train of broadband pulses with successively increasing central frequencies was used to overcome major challenges posed by the short positronium lifetime and the effects of Doppler broadening and recoil. One-dimensional chirp cooling was used to cool a portion of the dilute positronium gas to a velocity distribution of approximately 1 K in 100 ns. A major advancement in the field of low-temperature fundamental physics of antimatter, this study on a purely leptonic system complements work on antihydrogen13, a hadron-containing exotic atom. The successful application of laser cooling to positronium affords unique opportunities to rigorously test bound-state quantum electrodynamics and to potentially realize Bose–Einstein condensation14–18 in this matter–antimatter system.The one-dimensional laser cooling of positronium enables testing of quantum electrodynamics and could realize Bose–Einstein condensation in positronium. [ABSTRACT FROM AUTHOR]

We study the momentum correlation functions of p Ξ - and Λ Λ pairs produced in high-energy nuclear collisions by using the coupled-channel framework and the N Ξ - Λ Λ coupled-channel baryon-baryon potentials recently obtained from lattice QCD calculations at almost physical quark masses. The calculated results are found to well describe the correlation function data from pp and pPb collisions. This agreement confirms the S = - 2 baryon-baryon potentials from lattice QCD and supports the existence of the H dibaryon as a virtual state around the N Ξ threshold. [ABSTRACT FROM AUTHOR]

We report on a recent calculation of the properties of the DNN system, a charmed meson with two nucleons. The system is analogous to the $${{\bar {K}}NN}$$ system substituting a strange quark by a charm quark. Two different methods are used to evaluate the binding and width, the Fixed Center approximation to the Faddeev equations and a variational calculation. In both methods we find that the system is bound by about 200 MeV and the width is smaller than 40 MeV, a situation opposite to the one of the $${{\bar {K}}NN}$$ system and which makes this state well suited for experimental observation. [ABSTRACT FROM AUTHOR]

Recent developments of the Slow Positron Facility at the Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) are reported. We have modified the converter/moderator assembly for slow positron beam production, yielding an increase of an order of magnitude in the intensity of the beam. The first observation of the photodetachment of the positronium negative ion (Ps), and the installation of a reflection high-energy positron diffraction (RHEPD) station and the initial data obtained are reported. [ABSTRACT FROM AUTHOR]

The aim of this study was to retrospectively evaluate the safety and efficacy of polidocanol sclerotherapy in pain relief for painful venous malformations (VMs). Thirty-one patients with painful VMs underwent polidocanol sclerotherapy. Pain intensity was assessed with an 11-point verbal numerical rating scale. Sclerotherapy was technically successful in 58 (98.3%) of 59 sessions. Twenty-six (89.7%) out of 29 patients experienced an improvement in pain after sclerotherapy at follow-up, a mean of 46 months after treatment. The mean pain score improved from 6.6 + or - 2.5 before treatment to 2.4 + or - 2.9 after treatment (P <.001). The factors that significantly influenced the therapeutic effect were size of lesion (P = .008), margin of lesion (P = .006), and stasis of sclerosant (P = .032). Adverse events included hypotension and bradycardia during the procedure. No major complication occurred. Polidocanol sclerotherapy is safe and most efficacious in providing pain relief for patients with small VMs (equal to or less than 10 cm in diameter), VMs with a well-defined margin, and VMs with good stasis of sclerosant during sclerotherapy. [ABSTRACT FROM AUTHOR]

We present a case of sarcomatoid renal cell carcinoma (RCC). Although preoperative computed tomography (CT) scans demonstrated small lung and pleural nodules and mediastinal lymphadenopathy, these findings were not conclusive for metastases. Whole-body fluorine-18 fluorodeoxyglucose positron emission tomography and CT (FDG-PET/CT) performed 15 days after right nephrectomy showed intense FDG uptake in the aforementioned lesions (lung and pleural nodules, mediastinal lymph nodes). Unexpectedly, focal increased FDG uptake was found in the right infraspinatus muscle. FDG-PET/CT was considered useful for evaluating distant metastases and thus portending the aggressive nature of sarcomatoid RCC. [ABSTRACT FROM AUTHOR]

The effect of heat treatment on silica aerogel has been studied by a positron age–momentum correlation technique and infrared measurement. A difference was observed between the momentum distributions of the electrons on the first layers of the silica aerogel grain surfaces and the electrons in the grains in an as-supplied sample, but not in the sample heat treated at 800 °C. A large change in the S parameter for the momentum distribution of the electrons on the first layer occurs around 200 °C. This change correlates well with that of the infrared spectra, which show oxidation of the methoxyl groups at temperatures above around 200 °C. This correlation reveals that those groups are mainly located on the first layer of the silica grains. [ABSTRACT FROM AUTHOR]

Core/shell microspheres of polymethylmethacrylate coated with Al2O3 or a mixture of Al2O3 and SiO2 nanoparticles have been successfully prepared by a mechanofusion system. The microspheres were then subjected to removal of PMMA by firing in air, followed by sintering at 1600°C for 3 h. The shell structure was destroyed after the sintering when the shell layer consisted of only Al2O3. The addition of SiO2 was found to be effective for maintaining the original shell structure, while the shell size expanded slightly and a hole was formed in each hollow microsphere during the removal process of PMMA. [ABSTRACT FROM AUTHOR]

Palliative duodenal stenting was attempted in three patients with severe duodenal stenosis due to tumor invasion. Two methods were applied for duodenal stenting: the conventional method, which inserts the Ultraflex (stent for esophageal stenosis) along the guidewire under fluoroscopy, and a new method that uses a snare and an endoscope to guide the esophageal stent. The conventional method is often unsuccessful, because the delivery tube is too short, but the latter method appears to be a safe and effective duodenal stenting technique. [ABSTRACT FROM AUTHOR]

Presents a measurement system for temperature and velocity vector distributions in a three-dimensional thermal flow field. Use of thermo-sensitive liquid crystal tracers in the accomplishment of flow visualization; Application of algorithm for the color-to-temperature transformation; Interpolation of two-dimensional distributions.

The development of endoscopic biliary stenting (EBS), using the Wallstent, to treat patients with obstructive jaundice secondary to unresectable tumors of the pancreas or biliary ducts has led to improved quality of life in these patients. We followed six patients with intraductal ultrasonography (IDUS) after insertion of a Wallstent. In two patients, endoscopic ultrasonography (EUS) was also performed, and in three patients IDUS was repeated every few months. IDUS allowed ingrowth of the tumor or formation of debris in the stent to be observed clearly and easily. Therefore IDUS was considered to be a powerful tool to follow patients after stenting and to decide on the next treatment when reobstruction occurred. [ABSTRACT FROM AUTHOR]