Standard error and confidence interval for QALY weights

There are some problems with the standard errors of QALY weights proposed by Groot (2000, Journal of Health Economics 19). The standard errors show smaller values than those of Groot when we recalculate using his method. Moreover, we correct the derivation of his approximation and derive corrected values. Because mean and variance do not exist for a distribution of QALY weights, using standard errors for statistical inference may lead to problems even when an approximation is used. In this paper, we verify the statistical properties of Groot's standard errors by simulation. We find that the corrected standard errors hold the same properties as a normal distribution under specific conditions. In general, however, it would be appropriate to use our simulation method to obtain critical values or p-value.

Informal and formal care for elderly persons: How adult children's characteristics affect the use of formal care in Japan

Informal care by adult children remains the most common source of caregiving for elderly parents in Japan, even after the introduction of long-term care insurance in 2000. We estimate how the potential supply of child caregivers affects the use of formal care of elderly parents, focusing on the differences across children. We find that the effects of children's presence vary substantially with gender, marital status, and opportunity costs of children. The potential supply of daughters-in-law, as the traditional source of informal care, is less important in providing care than that of unmarried children. The opportunity costs of children make a difference in the use of formal long-term care.Japan Informal care Long-term care insurance Aging Daughters-in-law

Determination of a pain substance produced by the photodegradation of dacarbazine

The anticancer drug, dacarbazine, is known to be photosensitive, and its photodegradation products have been pointed out as the causes of side effects including local venous pain of injection site. In this study, we attempted to clarify the causative substance of pain after photodegradation of dacarbazine. We synthesized five photodegradation products of dacarbazine; dimethylamine, 5-diazoimidazole-4-carboxamide (Diazo-IC), 4-carbamoylimidazolium-5-olate, 4-carbamoyl-2-(4-carbamoylimidazol-5-ylazo) imidazolium-5-olate and 2-azahypoxanthine, and examined pain reactions induced by these substances in mice. Mice were intraperitoneally administered each photodegradation product, then number of stretching reactions or writhing reactions as types of pain behaviors was counted. Only Diazo-IC clearly induced the pain reactions in mice in a concentration-dependent manner: the other products caused no pain reaction. The pain threshold of Diazo-IC in mice was estimated at between 0.1 mg/ml and 0.2 mg/ml. While diclofenac sodium significantly reduced acetic acid-induced pain reactions in mice, it did not influence the reactions induced by Diazo-IC. This result suggests that Diazo-IC-induced pain reactions represent a different mechanism from acetic acid-induced inflammatory pain. Degradation rate constant of 0.1 mg/ml of dacarbazine solution was 10 times larger than 1 mg/ml of dacarbazine. Dacarbazine solution for drip infusion should be sufficiently shielded from light

Solvothermal Synthesis of −LIT-type Zeolite

Lithosite (<b>−LIT</b>) type aluminosilicate zeolites were successfully synthesized, for the first time, by solvothermal treatment of low-silica zeolite powders. The starting materials comprised H–Y zeolite samples having different SiO₂/Al₂O₃ ratios, together with NH₃⁺-exchanged chabazite and NH₃⁺-exchanged phillipsite. The low-silica zeolite powders were dispersed in alcohol containing dissolved KOH, and the mixture was solvothermally treated at 200–250 °C for 15–120 h without stirring. The crystal structure of the obtained sample was analyzed by the Rietveld method which indicated it to be single phase <b>–LIT</b> zeolite (monoclinic, space group <i>P</i>2₁, <i>a</i> = 1.513 nm, <i>b</i> = 1.023 nm, <i>c</i> = 0.842 nm, β = 89.99°). The scanning electron microscopy images show that the obtained product consists of blade-like particles. The SiO₂/Al₂O₃ ratios of the <b>–LIT</b> samples varied from 4.0 to 6.7 based on the composition of the starting materials. The zeolite pores were hydrophilic in nature; however, potassium cations contained in the micropores were hardly exchanged at room temperature. Furthermore, Co-substituted <b>–LIT</b> zeolite was also successfully synthesized by a similar method as that used for <b>–LIT</b>-type aluminosilicate zeolite, using Co²⁺-exchanged H–Y zeolite as the starting material