We investigated the origin of birefringence in colloidal films of spherical silica particles. Although each particle is optically isotropic in shape, colloidal films formed by drop drying demonstrated birefringence. While periodic particle structures were observed in silica colloidal films, no regular pattern was found in blended films of silica and latex particles. However, since both films showed birefringence, regular film structure patterns were not required to exhibit birefringence. Instead, we propose that nanometer-scale film structure anisotropy causes birefringence. Due to capillary flow from the center to the edge of a cast suspension, particles are more tightly packed in the radial direction. Directional packing results in nanometer-scale anisotropy. The difference in the interparticle distance between radial and circumferential axes was estimated to be 10 nm at most. Nanometer-scale anisotropy in colloidal films and the subsequent optical properties are discussed.

Intraperitoneal chemotherapy demonstrates potential applicability in the treatment of peritoneally disseminated ovarian cancer because the disseminated tumors can directly receive exposure to high concentrations of anticancer drugs. However, a considerable proportion of drugs, particularly micromolecular and hydrophilic drugs, such as cisplatin (CDDP), are often excreted through glomerular filtration for a short period. To effectively deliver CDDP into peritoneally disseminated ovarian cancer tissues, we developed an alginate (AL)-based hybrid system in which a CDDP-loaded AL nanogel (AL/CDDP-nanogel) was encapsulated in an injectable AL-hydrogel cross-linked with calcium ions. This system enabled the sustained release of CDDP from the AL/CDDP-nanogel/AL-hydrogel hybrid for over a week. Herein, we constructed a peritoneally disseminated ovarian cancer mouse model using ovarian cancer cell lines with KRAS mutations (ID8-KRAS: KRASG12V). The AL/CDDP-nanogel/AL-hydrogel hybrid system showed significant antitumor activity in vivo. This therapy may be considered a novel strategy for the treatment of advanced-stage ovarian cancer with KRAS mutations.

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Background Small cell carcinoma of the uterine cervix (SCCC) is a rare and highly malignant human papillomavirus (HPV)‐associated cancer in which human genes related to the integration site can serve as a target for precision medicine. The aim of our study was to establish a workflow for precision medicine of HPV‐associated cancer using patient‐derived organoid. Methods Organoid was established from the biopsy of a patient diagnosed with HPV18‐positive SCCC. Therapeutic targets were identified by whole exome sequencing (WES) and RNA‐seq analysis. Drug sensitivity testing was performed using organoids and organoid‐derived mouse xenograft model. Results WES revealed that both the original tumor and organoid had 19 somatic variants in common, including the KRAS p.G12D pathogenic variant. Meanwhile, RNA‐seq revealed that HPV18 was integrated into chromosome 8 at 8q24.21 with increased expression of the proto‐oncogene MYC. Drug sensitivity testing revealed that a KRAS pathway inhibitor exerted strong anti‐cancer effects on the SCCC organoid compared to a MYC inhibitor, which were also confirmed in the xenograft model. Conclusion In this study, we confirmed two strategies for identifying therapeutic targets of HPV‐derived SCCC, WES for identifying pathogenic variants and RNA sequencing for identifying HPV integration sites. Organoid culture is an effective tool for unveiling the oncogenic process of rare tumors and can be a breakthrough for the development of precision medicine for patients with HPV‐positive SCCC.

We studied the growth kinetics of needle-like silicon wires formed in the reduction reaction of silicon tetrachloride (SiCl 4 ) with zinc vapor. Real-time monitoring of the silicon wire growth was performed using a quartz tube reactor with a charge-coupled device (CCD) camera. The formation of silicon wires was observed when SiCl 4 was mixed with zinc vapor; the wires grew at a constant rate, which reached 20 mm min −1 . We did not prepare catalytic metal particles in the reactor; however, since zinc metal can form a liquid alloy with silicon at reaction temperatures of ca. 900−950 °C, we proposed that a vapor−liquid−solid (VLS) mechanism was responsible for the formation of the silicon wires. We consider that the zinc acted both as a reducing agent for SiCl 4 and as a metal catalyst for the wire formation. On the basis of the VLS mechanism, a simple kinetic model for wire growth was proposed. Our model described the experimental data well, and the rate-limiting step for the wire growth is the gas-phase reduction of SiCl 4 . The activation energy for the wire growth was 2.8 × 10 2 kJ mol −1 .