Motion-Induced Transition of Positronium through a Static Periodic Magnetic Field in the Sub-THz Region

Atoms moving in a static periodic field experience a time-dependent oscillating field in their own rest frame. By tuning the frequency, an atomic transition can be induced. So far, this type of transition has been demonstrated in the EUV region or at higher frequencies by crystalline fields and in the microwave region by artificial fields. Here, we present the observation of the transition of positronium (Ps) in the sub-THz region by using an energy-tunable Ps beam with a multilayered magnetic grating. This grating produces a microsized periodic field, whose amplitude corresponds to a huge energy flux of ∼100  MW cm^{-2}, resulting in the efficient magnetic dipole transition.

Effects of the time-of-day (morning vs. afternoon) of implementing a combined physical and cognitive exercise program on cognitive functions and mood of older adults: A randomized controlled study

This study examined the effects of the time of conducting a combined physical and cognitive exercise program on cognitive functions and the mood of older adults. We randomly assigned 17 participants (8 men, 9 women, age 73,24±3,75) to the morning group (AM Group), 18 (8 men, 10 women, age 73,11±4,84) to the afternoon group (PM Group), and they completed a 12-week, dual-task exercise program in the morning or the afternoon, respectively. Moreover, the waiting-list control group consisted of 12 participants (6 men, 6 women, age 73,25±5,93). The cognitive functions and the mood of the participants were assessed before and after the program by using the Neurobehavioral Cognitive Status Examination, and the short version of the Profile of Mood States, respectively. As a result, the exercise program conducted in the afternoon had broader effects on cognitive functions (increased Repetition and Memory) than in the morning (increased Repetition), or the waiting-list control group (increased Judgment). Moreover, the program in the afternoon tended to reduce Anger-Hostility, and Fatigue. In conclusion, conducting the exercise program in the afternoon might be more effective for improving cognitive functions and the mood of older adults than in the morning. However, there was heterogeneity between the groups despite the randomization. Therefore, we suggest conducting a more rigorously controlled study using a larger sample to validate these findings.

A high-quality and energy-tunable positronium beam system employing a trap-based positron beam

We constructed a new apparatus, built upon a trap-based slow positron beam, for the production of a collimated, energy-tunable positronium beam under ultra-high vacuum conditions employing the photodetachment of positronium negative ions. A slow positron generator consisting of a ²²Na radioisotope (20 mCi) combined with a buffer-gas positron trap is employed to generate high-quality, nano-second positron bursts with a repetition rate of 1 Hz-1 kHz. The positron bursts are focused onto an efficient positron-to-positronium negative ion converter, a Na-coated W thin film in a transmission geometry, using a magnetic lens system. The ions emitted from the opposite surface of the film are electrostatically accelerated to a given energy and photodetached by a pulsed infrared laser to form a mono-energetic positronium beam with kinetic energies of 0.2 keV-3.3 keV. The achieved detection rate of Ps atoms is 23 cps at the energy of 3.3 keV with a signal-to-background ratio as high as 300. The energy spread of the beam was evaluated by comparing the result of the time-of-flight measurements and particle-tracking simulations. With the use of a collimator of 1 mm diameter, a coherent beam with an angular divergence of less than 0.3° is obtained. The obtained Ps beam, having a much higher quality than those reported hitherto, will open up a new field of experimental investigations, such as Ps interacting with a variety of materials and fundamental studies on Ps spectroscopy.

Fast-framing camera based observations of spheromak-like plasmoid collision and merging process using two magnetized coaxial plasma guns

We have been conducting compact toroid (CT) collision and merging experiments by using two magnetized coaxial plasma guns. As is well known, an actual CT/plasmoid moves macroscopically in a confining magnetic field. Therefore, three-dimensional measurements are important in understanding the behavior of the CTs. To observe the macroscopic process, we adopted a fast-framing camera (ULTRA Cam HS-106E) developed by NAC Image Technology. The characteristics of this camera are as follows: a CCD color sensor, capable of capturing 120 images during one sequence with a frame rate of up to 1.25 MHz. Using this camera, we captured the global motion of a CT inside the magnetic field and the collision of two CTs at the mid-plane of the experimental device. Additionally, by using a color sensor, we captured the global change in the plasma emission of visible light during the CT collision/merging process. As a result of these measurements, we determined the CT's global motion and the changes in the CT's shape and visible emission. The detailed system setup and experimental results are presented and discussed.

Internal magnetic field measurements of translated and merged field-reversed configuration plasmas in the FAT-CM device

Field-reversed configuration (FRC) Amplification via Translation-Collisional Merging (FAT-CM) experiments have recently commenced to study physics phenomena of colliding and merged FRC plasma states. Two independently formed FRCs are translated into the confinement region of the FAT-CM device, collided near the mid-plane of the device with a relative speed of up to ∼400 km/s, and a final merged FRC plasma state is achieved. To measure internal magnetic field profiles of the translated and merged FRC plasmas as well as to understand its collisional-merging process, an internal magnetic probe array, developed by TAE Technologies, has been installed in the mid-plane of the FAT-CM device. Initial magnetic field measurements indicate that both the translated and the merged FRC plasma states exhibit a clear field-reversed structure, which is qualitatively in good agreement with 2D MHD simulation. It is found and verified that a sufficient mirror field in the confinement region is required for colliding FRCs to be fully merged into a single FRC plasma state.

Cytological markers for predicting ALK-positive pulmonary adenocarcinoma

BACKGROUND

ALK gene rearrangement is an important class of gene mutations in pulmonary adenocarcinoma. ALK-positive pulmonary adenocarcinoma exhibits characteristic histological features, such as signet ring cell carcinoma (SRCC) and a mucinous cribriform structure. However, when insufficient histological specimens are obtained, ALK-positivity must be predicted based on cytological features. The purpose of this study was to clarify the cytological characteristics of ALK-positive pulmonary adenocarcinoma.

METHODS

We compared the cytological findings of 16 ALK-positive cases with 40 ALK-negative cases. We examined various cytoplasmic features of SRCC, including the presence of pink, yellow, or orange mucin; green, vacuolar, or vesicular cytoplasm; and green globular cytoplasmic secretions. We also examined whether the SRCC cells exhibited a pattern of individually scattered cells, the formation of cell clusters, and formation of a mucinous cribriform pattern.

RESULTS

A univariate analysis showed that significantly frequent cytological findings included pink mucin, green cytoplasm, vacuolar cytoplasm, vesicular cytoplasm, green globular cytoplasmic secretions, an individually scattered pattern, cluster formation, and a mucinous cribriform structure (all, P < .05). A stepwise multivariate logistic regression analysis identified three significant contributing factors: pink mucin (P = .03), vesicular cytoplasm (P = .06), and an individually scattered pattern (P = .01) of SRCC. If the specimens showed two or three of these features, the sensitivity and specificity were both 88% for the prediction of ALK-positive cancers.

CONCLUSION

Three cytological features of SRCC (pink mucin, vesicular cytoplasm, and an individually scattered pattern) could be useful cytological markers for the prediction of ALK-positive pulmonary adenocarcinoma.

Acute Electrolyte Disturbances in Coronary Sinus during Left Coronary Arteriography in Man

Electrolyte disturbances, particularly reduction of ionized calcium, induced by iodinated contrast media (CM) are important considerations in coronary arteriography. A study was conducted in 24 patients to evaluate the acute electrolyte alterations in the coronary sinus during left coronary arteriography. During left coronary arteriography, coronary sinus blood was withdrawn for measurement of electrolytes. The CM used were diatrizoate, ioxaglate, iohexol, and iopamidol. The hematocrit was decreased moderately by all 4 CM used at 5 s and returned to the control level at 15 s. The level of ionized calcium was decreased by all CM at 5 s. Prolonged reduction of ionic calcium was observed with diatrizoate and ioxaglate at 15 s. The level of potassium was almost unchanged by diatrizoate and ioxaglate in spite of hemodilution, which may lead us to a hypothesis that potassium can be released from the intracellular spaces such as red blood cells and vascular endothelial cells. Thus the depression of left ventricular function might be caused not only by reduction of ionized calcium, but also by a relative increase in the level of serum potassium.

Effect of hypoxia on UDP-glucuronosyl transferase mRNA expression in human hepatocarcinoma functional liver celL4 cell line

Although hypoxic conditions have been reported to affect the expression levels of various enzymes like cytochrome P450, the effect of hypoxia for UDP-glucuronosyl transferase (UGT) expression has been unclear. We evaluated the mRNA expression of UGTs (UGT1A1·1A6·1A9·2B7) in a functional liver cell-4 (FLC-4) cell line by three-dimensional culture under hypoxic conditions (37 °C, 1% O₂, 5% CO₂) fo 7 days. The mRNA expression of UGT1A1·1A6·1A9·2B7 decreased significantly after 3 days and that of UGT1A1·1A6·1A9 decreased significantly after 7 days. Hypoxic conditions affect the expression levels of UGT enzymes, thus the adjustment of dosage and interval should be considered in drug therapy that metabolized by UGT.

Enteric glial cells are associated with stress-induced colonic hyper-contraction in maternally separated rats

BACKGROUND

Enteric glial cells (EGCs) play important roles in enteric integrity and regulation of gastrointestinal function. However, whether EGCs undergo pathophysiological changes in stress-associated gastrointestinal disorders is unknown. We investigated structural and functional alterations in colonic EGCs and their roles in colonic contraction in an irritable bowel syndrome (IBS) model.

METHODS

As a chronic stress, male Wistar rats underwent 3-h maternal separation during postnatal days 2-14. As an acute stress, we used water-immersion stress (4 h) in adulthood (at 8 weeks). We quantitatively and morphologically evaluated enteric neurons and EGCs using whole-mount longitudinal muscle-myenteric plexus preparations. Colonic contraction was analyzed with electrical field stimulation (EFS).

KEY RESULTS

Glial fibrillary acidic protein (GFAP) expression and the number of total, cholinergic, and nitrergic neurons were unchanged in maternally separated rats with acute stress (combined stress: an IBS model) compared with controls. However, the density of GFAP-positive EGC processes that apparently overlapped with the neurons and the extent of bulbous swelling of terminals increased according to the stress intensity: control, acute stress, maternal separation, and combined stress. EFS-induced colonic contractions were significantly greater in the combined stress rats than in controls. Higher dose of fluorocitrate, a selective inhibitor of EGC metabolism, was required to inhibit both EFS-induced contraction and EGCs activation in the combined stress rats than in controls.

CONCLUSIONS & INFERENCES

Colonic EGCs exhibited structural alterations according to the stress intensity. EGCs were associated with stress-induced colonic hyper-contraction in the combined stress rats, which may underlie the pathogenesis of IBS.

Basophil infiltration in eosinophilic oesophagitis and proton pump inhibitor-responsive oesophageal eosinophilia

BACKGROUND

The features of proton pump inhibitor-responsive oesophageal eosinophilia (PPI-REE) are similar to those of eosinophilic oesophagitis (EoE), but PPI-REE demonstrates symptomatic and histological responses to PPI therapy. Several studies have shown that basophils play a crucial role in the pathogenesis of allergic diseases.

AIM

To identify and compare basophil infiltration in the oesophageal epithelium in patients with EoE, PPI-REE, gastroesophageal reflux disease (GERD) and normal oesophagus (controls).

METHODS

Biopsy specimens from 43 patients, including 12 with EoE, 11 with PPI-REE, 10 with GERD and 10 normal oesophagus, were analysed. Immunohistochemistry was performed to quantify the number of basophils and mast cells in the oesophageal epithelium. Double immunofluorescence staining for thymic stromal lymphopoietin (TSLP) and basophils was performed. Patients with EoE were treated with swallowed fluticasone.

RESULTS

There were no differences in clinical, endoscopic or histological features between patients with EoE and PPI-REE. There were more basophils and mast cells in patients with EoE and PPI-REE than in patients with GERD and control subjects. Basophil infiltration of the oesophageal epithelium in patients with EoE was higher than that in patients with PPI-REE (3.6 ± 2.8 per high power field vs. 1.2 ± 0.9 per high power field respectively; P = 0.02); however, there was no significant difference in mast cell infiltration between the two groups. TSLP was highly expressed in the oesophageal epithelium in areas infiltrated by basophils. Steroid therapy significantly decreased intraepithelial basophils in patients with EoE.

CONCLUSION

Basophils may play an important role in the pathogenesis of eosinophilic oesophagitis.