Molecular crystalline capsules that release their contents by light.

Here, we present single crystalline capsules of a photoresponsive molecule produced by simple recrystallization from organic solutions without direct human processing. During the crystal growth process, a movie was taken of the capsule taking in the organic solution. The capsules responded rapidly (<1 s) to the UV light stimuli and released the captured solution or solute. In principle, they can take in any substance dissolved in organic solvents, and their size can be controlled. Moreover, the capsule can be broken by multi-photon excitation using a near-infrared laser within the biological window. Furthermore, because the molecular packing in the crystal is unidirectional, the response can be controlled by the polarization of the light. This study shows the new potential of photoresponsive molecules.

Histological comparison of malignant epithelioid mesothelioma in young and adult cattle.

The histology and immunohistochemistry of pleomorphic and conventional epithelioid mesotheliomas were examined. The former was detected in two young calves aged 2 and 4 months and was characterized by pleomorphic and atypical cells with decreased expression of cytokeratin 7 (CK7). In contrast, the latter was found in a 31-month-old heifer, consisting of tumor cells uniform in size and shape with CK7 expression in nearly all cells. Production of collagen by tumor cells was demonstrated in both histological types, and was considered to be characteristic of bovine epithelioid mesothelioma. Pleomorphic mesothelioma is far more pleomorphic and mitotically active than conventional mesothelioma, and its normal counterpart may be immature mesothelial cells with high proliferation potential, which exist in fetal life and early calfhood.

Predation impacts of invasive raccoons on rare native species.

In Japan, there are concerns that invasive alien raccoons prey on rare native species during their spawning season from late winter to early summer. We investigated raccoon predation impact by examining the predation presence using DNA metabarcoding and extent of predation on rare native species using stable isotope analysis. We captured raccoons in Hokkaido, Japan from April to August in 2018 and 2019. We analysed raccoon faeces and gastric contents by DNA metabarcoding to detect the rare native Hokkaido salamander and Japanese crayfish. Hokkaido salamanders were detected from gastric contents, but Japanese crayfish were not detected in any samples. Stable isotope analysis of raccoon muscle samples and the Bayesian mixing model were used to estimate each food resource's contribution to the raccoon diet. Animal food resources accounted for 70% of total consumed food. The foraging ratios of amphibians and crustaceans were about 9% and 5%, respectively. Raccoons have been found to use amphibians at a higher rate than previously reported, including a rare endangered species, the Hokkaido salamander. Hokkaido salamander and Japanese crayfish spawn in the spring, and increased predation pressure by raccoons may directly impact populations of these rare native species.

[Optimization of Echo Train Length in Non-contrast Enhanced MR Angiography for Clinical Examination of the Calf Arteries].

PURPOSE: Non-contrast magnetic resonanse angiography (MRA) using the three-dimensional electrocardiogram-synchronized fast spin echo method uses systolic and diastolic arterial signal differences. The method relies on the flow void signal of the arterial flow because of dephasing during systole. However, depiction of slow flow such as that in a calf artery was degraded because of insufficient dephasing during systole. In this study, we optimized echo train length (ETL) using a flow phantom and normal volunteers for clinical examination of the calf arteries. METHODS: Flow phantom and normal volunteer images were obtained with various ETLs (40, 50, 60, and 70). An averaged profile across the tube in the phantom was used for detailed investigation of flow dephasing. Visual evaluation was performed and signal intensity change along vessels was measured using normal volunteer images. Comparison with peak systolic velocity (PSV) measured using ultrasound equipment was also conducted. RESULTS: Results of the flow phantom and normal volunteer study indicated that the overall depictability was improved with ETL 60 and 70, which was higher than the standard value. Additionally, the visualization of the peroneal artery with low PSV of ETL 70 had better depictability than ETL 60. CONCLUSION: This study suggested that ETL 70 might be better for clinical examination of the calf arteries.

Photoinduced swing of a diarylethene thin broad sword shaped crystal: a study on the detailed mechanism.

We report a swinging motion of photochromic thin broad sword shaped crystals upon continuous irradiation with UV light. By contrast in thick crystals, photosalient phenomena were observed. The bending and swinging mechanisms are in fact due to molecular size changes as well as phase transitions. The first slight bending away from the light source is due to photocyclization-induced surface expansion, and the second dramatic bending toward UV incidence is due to single-crystal-to-single-crystal (SCSC) phase transition from the original phase I to phase IIUV. Upon visible light irradiation, the crystal returned to phase I. A similar SCSC phase transition with a similar volume decrease occurred by lowering the temperature (phase IIItemp). For both photoinduced and thermal SCSC phase transitions, the symmetry of the unit cell is lowered; in phase IIUV the twisting angle of disordered phenyl groups is different between two adjacent molecules, while in phase IIItemp, the population of the phenyl rotamer is different between adjacent molecules. In the case of phase IIUV, we found thickness dependent photosalient phenomena. The thin broad sword shaped crystals with a 3 µm thickness showed no photosalient phenomena, whereas photoinduced SCSC phase transition occurred. In contrast, large crystals of several tens of µm thickness showed photosalient phenomena on the irradiated surface where SCSC phase transition occurred. The results indicated that the accumulated strain, between isomerized and non-isomerized layers, gave rise to the photosalient phenomenon.

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene.

Background: Diarylethenes are well-known photochromic compounds, which undergo cyclization and cycloreversion reactions between open- and closed-ring isomers. Recently, diarylethene derivatives with photoswitchable fluorescent properties were prepared. They are applicable for fluorescence imaging including bio-imaging. On the other hand, a new system called "excited state intramolecular proton transfer (ESIPT)" is reported. In the system, absorption and emission bands are largely separated due to the proton transfer, hence it showed strong fluorescence even in the crystalline state. We aimed to construct the photochromic system incorporating the ESIPT mechanism. Results: A diarylethene incorporating a fluorescent moiety that exhibit ESIPT behavior was prepared. The ESIPT is one of the examples which express the mechanisms of aggregation-induced emission (AIE). This compound emits orange fluorescence with a large Stokes shift derived from ESIPT in aprotic solvents such as THF or hexane, while it exhibits only a photochromic reaction in protic solvents such as methanol. In addition, it shows turn-off type fluorescence switching in an aprotic solvent and in crystals. The fluorescence is quenched as the content of closed-ring isomers increases upon UV light irradiation. Conclusions: A diarylethene containing an ESIPT functional group was prepared. It showed fluorescent turn-off behavior during photochromism in aprotic solvents as well as in crystalline state upon UV light irradiation. Furthermore, it showed AIE in THF/water mixtures with blue-shift of the emission.

Comparison of feeding habits and habitat use between invasive raccoons and native raccoon dogs in Hokkaido, Japan.

BACKGROUND: In Japan, invasive raccoons cause severe ecological and social problems by transmitting pathogens to humans, livestock, and native species, causing substantial crop damage, and competing with native species. Possible competition between invasive raccoons and native raccoon dogs is of concern in Japan because Japanese raccoon dogs have a limited distribution and are native only to Japan and the two species have similar characteristics. We assessed potential competition between raccoons and raccoon dogs by comparing feeding habits and habitat use. RESULTS: Both species were captured in Hokkaido, Japan from 2004 to 2017. More raccoons were captured close to agricultural land at the forest periphery (70.1%, 358/511); conversely, more raccoon dogs were captured in the forest core (74.9%, 253/338). Feeding habits were then examined by fecal analysis and stable isotope analyses. Fecal analysis revealed both species to be opportunistic omnivores that consumed easily found food items. However, raccoon feces contained more crops, whereas raccoon dog feces contained more insects, reflecting the different locations in which the species were trapped. Moreover, stable isotope ratios were significantly higher in raccoons than raccoon dogs (Corn has the highest carbon stable isotope (δ13C) value, and amphibians and reptiles are high in nitrogen stable isotope (δ15N); forest resources such as insects and wild fruits are low in δ13C and δ15N). CONCLUSIONS: We conclude that both species ate similar food types, but their food preferences appeared to differ. Raccoon and raccoon dog habitat use also differed, possibly because the two species inhabited areas where they could easily obtain their preferred foods. Therefore, the current feeding habits and habitat use of raccoons do not appear to overlap sufficiently with those of raccoon dogs to impact the latter. The results of this study, particularly the stable isotope data, may provide a useful precedent for future studies of competition in medium-sized mammals, particularly canids.

Object Transportation System Mimicking the Cilia of Paramecium aurelia Making Use of the Light-Controllable Crystal Bending Behavior of a Photochromic Diarylethene.

The design of an object transportation system exploiting the bending behavior of surface-assembled diarylethene crystals is reported. A photoactuated smart surface based on this system can transport polystyrene beads to a desired area depending on the direction of the incident light. Two main challenges were addressed to accomplish directional motion along a surface: first, the preparation of crystals whose bending behavior depends on the direction of incident light; second, the preparation of a film on which these photochromic crystal plates are aligned. Nuclei generation and nuclear growth engineering were achieved by using a roughness-controlled dotted microstructured substrate. This system demonstrates how to achieve a mechanical function as shown by remote-controlled motion along a surface.

Photosalient Phenomena that Mimic Impatiens Are Observed in Hollow Crystals of Diarylethene with a Perfluorocyclohexene Ring.

A diarylethene with a perfluorocyclohexene ring formed hollow crystals by sublimation under normal pressure. Upon UV irradiation of the crystals, they showed remarkable photosalient phenomena and scattered into small pieces. The speed of the flying debris released from the crystal by UV irradiation exceeded several meters per second. To clearly show a photosalient effect resembling the scattering behavior of Impatiens on a smaller scale, small fluorescent beads (1-µm diameter) were inserted into the hollow crystal. Consequently, scattering of the beads was observed as UV irradiation caused deformation and bursting of the hollow structure. This phenomenon is unique to hollow crystals, and the ability to effectively induce remarkable photosalient phenomena is similar to the behavior of hollow-structured Impatiens in nature.

Successful Treatment of Bing-Neel Syndrome Accompanying Waldenström's Macroglobulinemia with R-MPV: A Case Report.

Waldenström's macroglobulinemia (WM) is a neoplasm of lymphoplasmacytic cells that produces monoclonal IgM protein. Although hyperviscosity syndrome is a common feature of WM, central nervous system (CNS) involvement in WM is rare and is known as Bing-Neel syndrome. A 60-year-old woman was referred to our hospital with bed-bound polyneuropathy, edema, splenomegaly, IgM-λ-type monoclonal protein and CD20-positive lymphocyte infiltration in the bone marrow. She was diagnosed with WM accompanying POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) and was treated with rituximab and thalidomide. She achieved partial remission of WM, and thalidomide was continued for POEMS syndrome. She visited our outpatient clinic 6 years later with sudden onset of vertigo and nausea. Magnetic resonance imaging (MRI) revealed a low-density area 4 cm in diameter in her right cerebrum and right mid-brain and she was referred to our hospital. Pathological analysis of brain biopsy samples revealed diffuse large B-cell lymphoma (DLBCL) in the CNS. Nucleic acid sequence analysis of the VDJ region using DNA obtained from the original WM tumor cells and brain tissue revealed that the DLBCL cells were derived from the original WM malignant lymphoma cells. She received five cycles of rituximab, methotrexate, procarbazine, and vincristine (R-MPV) therapy and 23.4 Gy of whole-brain irradiation followed by two cycles of high-dose cytarabine, which resolved her neurological symptoms in association with reduction of IgM levels to 367 mg/dL. MRI and computed tomography of the brain demonstrated complete remission of her CNS lymphoma.

Mast cell sarcoma with megakaryocytic differentiation in a calf.

A case of mast cell sarcoma in a 5-month-old Holstein female calf is described. Macroscopically, enlargement of the spleen, lymph nodes, tonsils and kidneys was noted, and there were tumor masses in the neck region and on the pleura and peritoneum. The pericardium and uterine and ureter walls were also involved by tumor. Most neoplastic cells had eosinophilic granules, which were metachromatic and positive for naphthol AS-D chloroacetate esterase and tryptase, whereas smaller numbers of cells were positive for factor VIII-related antigen, a marker of megakaryocytes. Some of the predominant type of these tumor cells were found within the epithelia of the lungs, tonsils, gastrointestinal tract, liver, ureters, urinary bladder and uterus. Their normal counterparts were considered to be globule leukocytes.