This paper describes preparing radiopure molybdenum trioxide powder enriched with Mo-100 isotope for the AMoRE-II experiment. AMoRE-II, the second phase of the AMoRE experiments, will search for the neutrinoless double-beta decay (0νDBD) of the 100Mo isotope using over 100 kg of 100Mo embedded in 200 kg of ultra-pure Li2100MoO4 bolometric crystals. Efficient purification technology was developed and adapted to purify 100MoO3 powder with a 5 kg per month production capacity. Based on the ICP-MS analysis of purified powder, the 232Th and 238U were reduced to <9.4 μBq/kg and <50 μBq/kg, respectively. The concentrations of potassium, transition metals, and heavy metals were lower than 1 ppm. HPGe counting confirmed the reduction of progenies from the 232Th and 238U decay chains, reporting upper limits of <27 μBq/kg for 228Ac and <16 μBq/kg for 228Th. The 226Ra activity was acceptable at 110 ± 30 μBq/kg. In the last 3 years, 100 kg of pure 100MoO3 powder was produced. The production yield for the final purified product was above 90%, while irrecoverable losses were under 1.5%, and all by-products could be recycled further.

Herpes zoster (HZ) results from the reactivation of latent varicella-zoster virus in the dorsal root ganglion neurons. The most common complication of HZ is post-herpetic neuralgia (PHN), characterized by persisting neuropathic pain in the affected dermatome after the rash recedes. The immune system is more compromised in older people, which leads to an increase in the incidence of HZ and PHN. Several studies have revealed that HZ or PHN is associated with an increased risk of malignancy in immune-suppressed patients. An 83-year-old man visited our pain clinic with facial pain 6 months after he was diagnosed with recurred HZ on the right V1 dermatome. He was diagnosed with HZ on the right C2 dermatome 5 years ago. He could not perform a right lateral gaze for the past 3 months. Moreover, the symptoms did not improve and the pain was aggravated on the face and head. We considered two possibilities: HZ affecting motor neuron and occult malignancy. Brain magnetic resonance imaging and magnetic resonance angiography showed a mass lesion that should have been differentiated, and his blood was positive for prostate specific antigen. The probability of occult malignancy should be taken into account in elderly patients with HZ or PHN.

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