Experimental study of fast-neutron production and moderation for accelerator-based BNCT system

This work aims to study the fast-neutron production and moderation for the development of a compact accelerator-based multi-port Boron Neutron Capture Therapy (AB-mBNCT) system. An initial energy distribution and the efficiency of a test moderator assembly (TMA) for fast neutrons from a tungsten (W) target bombarded with a 53 MeV proton beam were measured using organic scintillators. The experimental results were reproduced with reasonable accuracy by simulations using the PHITS code. This paper will discuss about the experimental outcome and the related benchmark calculations by PHITS code.

Involvement of Heat Shock Proteins on the Transcriptional Regulation of Corticotropin-Releasing Hormone in Medaka

Medaka (Oryzias latipes) are teleost fish with a XX/XY sex determination system. Recently, it was reported that high temperature (HT) induced the masculinization of XX medaka by increasing the levels of cortisol, a major glucocorticoid produced by interrenal cells in teleosts. Cortisol secretion is regulated by adrenocorticotropic hormone (ACTH) secreted from the pituitary gland, which is partly regulated by corticotropin-releasing hormone (CRH) secreted from the hypothalamus. In teleosts, two crh paralogs, named crha and crhb, have been identified. Recently, the expression of crhb but not crha was upregulated by HT during gonadal sex differentiation period in medaka and loss-of-functions of its receptors under HT suppressed masculinization of XX medaka and increase of cortisol levels, suggesting that crhb is involved in masculinization induced by HT. However, the transcriptional regulation of crhb under HT has not been elucidated. We analyzed the gene expression pattern in the hypothalamus of medaka embryos incubated under HT using DNA microarray. The expressions of heat shock protein (hsp) genes, such as hsp70.1 and hsp30, were increased. Overexpression of hsp70.1 or hsp30 in cultured rat hypothalamic 4B cells significantly induced crh gene expression. Moreover, hypothalamic hsp70.1-overexpressing transgenic medaka also showed increased crhb gene expression that increased cortisol levels compared with fish incubated at a normal temperature. These results provide the first evidence that HSPs induce cortisol levels by elevating crhb gene expression in the hypothalamus.

Microwave oscillator using piezoelectric thin-film resonator aiming for ultraminiaturization of atomic clock

We developed a microwave oscillator and a micro electromechanical systems-based rubidium cell for the miniaturization of atomic clocks. A thin-film bulk acoustic resonator (FBAR) having a resonant frequency of the fundamental mode in the 3.5 GHz band was employed instead of a crystal resonator. It delivers a clock transition frequency of Rb atoms of 3.417 GHz without the need for a complicated frequency multiplication using a phase-locked loop. This topology considerably reduces the system scale and power consumption. For downsizing the atomic clock system toward the chip level as well as mass production, a microfabricated gas cell containing Rb and N₂ gases was also developed. These microcomponents were incorporated into an atomic clock test bench, resulting in a clock operation with a short-term frequency instability of 2.1 × 10^-11 at 1 s. To the best of our knowledge, this is the first report of a coherent population trapping clock operation using an FBAR-based microwave oscillator as well as a microfabricated gas cell.

Mechanical Strength of Synthetic Casting Tape for Application to Fracture Treatment of Farm Animals

Compressive and torsional strength of cyclindrically formed synthetic casting tape for animals (Vetcast Plus™), composed of polyurethane-impregnated glass fibres, was investigated to determine its adequate application to fracture treatment of farm animals. After the completion of curing reaction, six-layered samples of the synthetic casting tape tolerated a compressive load of 6630 N (680 kgf). The sixlayered casting tape had also a torsional strength of 64 N · m. The compressive strength increased with time after the initiation of curing reaction. The time required for practical curing (achieving more than 60% of a final strength) was only 30 min, and that for complete curing 120 min. It was demonstrated that efficacious and safe fracture treatment of farm animals could be carried out using the synthetic casting tape for animals when a layer number appropriate to the total body weight of the patient animal was employed. The information obtained in this study is thought to be very useful in clinical practice.

Mechanical strength of poly-urethane-impregnated synthetic casting tape was investigated to determine its adequate application to fracture treatment of farm animals. It was demonstrated that mechanical strength of cylindrically formed samples of the casting tape depended upon the layer number, and the six-layered sample tolerated a compressive load of 6630 N and a torsional load of 64 N · m when completely cured.

Standard Protocol for Exchange of Health-checkup Data Based on SGML: The Health-checkup Data Markup Language (HDML)

Objectives: To develop a health/medical data interchange model for efficient electronic exchange of data among health-checkup facilities.

Results: A Health-checkup Data Markup Language (HDML) was developed on the basis of the Standard Generalized Markup Language (SGML), and a feasibility study carried out, involving data exchange between two health checkup facilities. The structure of HDML is described.

Results: The transfer of numerical lab data, summary findings and health status assessment was successful.

Conclusions: HDML is an improvement to laboratory data exchange. Further work has to address the exchange of qualitative and textual data.

Noninvasive Evaluation of CBF and Perfusion Delay of Moyamoya Disease Using Arterial Spin-Labeling MRI with Multiple Postlabeling Delays: Comparison with 15O-Gas PET and DSC-MRI

BACKGROUND AND PURPOSE

Arterial spin-labeling MR imaging with multiple postlabeling delays has a potential to evaluate various hemodynamic parameters. To clarify whether arterial spin-labeling MR imaging can identify CBF and perfusion delay in patients with Moyamoya disease, we compared arterial spin-labeling, DSC, and ¹⁵O-gas PET in terms of their ability to identify these parameters.

MATERIALS AND METHODS

Eighteen patients with Moyamoya disease (5 men, 13 women; ages, 21-55 years) were retrospectively analyzed. CBF values of pulsed continuous arterial spin-labeling using 2 postlabeling delays (short arterial spin-labeling, 1525 ms; delayed arterial spin-labeling, 2525 ms) were compared with CBF values measured by ¹⁵O-gas PET. All plots were divided into 2 groups by the cutoff of time-based parameters (the time of the maximum observed concentration, TTP, MTT, delay of MTT to cerebellum, and disease severity [symptomatic or not]). The ratio of 2 arterial spin-labeling CBFs (delayed arterial spin-labeling CBF to short arterial spin-labeling CBF) was compared with time-based parameters: time of the maximum observed concentration, TTP, and MTT.

RESULTS

The short arterial spin-labeling-CBF values were significantly correlated with the PET-CBF values (r = 0.63; P = .01). However, the short arterial spin-labeling-CBF value dropped in the regions with severe perfusion delay. The delayed arterial spin-labeling CBF overestimated PET-CBF regardless of the degree of perfusion delay. Delayed arterial spin-labeling CBF/short arterial spin-labeling CBF was well correlated with the time of the maximum observed concentration, TTP, and MTT (ρ = 0.71, 0.64, and 0.47, respectively).

CONCLUSIONS

Arterial spin-labeling using 2 postlabeling delays may detect PET-measured true CBF and perfusion delay in patients with Moyamoya disease. Provided its theoretic basis and limitations are considered, noninvasive arterial spin-labeling could be a useful alternative for evaluating the hemodynamics of Moyamoya disease.

The effect of aprepitant and dexamethasone combination on paclitaxel-induced hypersensitivity reaction

PURPOSE OF INVESTIGATION

Dexamethasone (DEX) is often administered to prevent paclitaxel (PTX)-induced hypersensitivity reactions (HSR). The DEX dose is reduced when administered in combination with aprepitant (APR). However, the influence of that dose reduction on PTX-induced HSR has not been thoroughly studied. The present authors aimed to investigate the effects of the combined administration of APR and DEX on PTX-induced HSR.

MATERIALS AND METHODS

Fifty-one patients who received a three-week PTX regimen in combination with APR and DEX were retrospectively analysed. The authors compared the dose of DEX with the incidence of HSR and other toxicities.

RESULTS

Patients were stratified into two groups depending on the DEX dose, > 20 mg (group D, 33 patients), and < 12 mg (group reD, 26 patients). The incidence of HSR in Groups D and reD were 51.5% (17/33) and 53.8% (14/26), respectively. The frequencies of other toxicities between the groups were comparable.

CONCLUSION

The findings suggest that although a reduction in DEX dose is possible when APR is co-administered, this does not affect the PTX-induced HSR. However, adverse effect should be closely monitored.