False-Positive Mediastinal Lymphadenopathy on 18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography after Rectal Cancer Resection: A Case Report of Thoracoscopic Surgery in the Prone Position

18F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (integrated FDG PET/CT) has been used to diagnose recurrence and differentiate postoperative changes from lymph node metastasis in colorectal cancer, although its accuracy is questionable. We report a prone thoracoscopic surgery for a rectal cancer patient in which false-positive mediastinal lymph nodes were found on FDG-PET/CT. A 60-year-old man underwent a laparoscopic high anterior resection and D3 lymph node dissection for rectal cancer. The histopathological diagnosis was moderately differentiated adenocarcinoma of the rectum, stage IIIB (pT3N1M0), necessitating oral fluoropyrimidine agent S-1. After the primary surgery, a solitary mediastinal lymph node measuring 30 mm in diameter was detected, and abnormal accumulation was confirmed by FDG-PET/CT (SUVmax, 11.7). Thoracoscopic resection was performed in the prone position, but histopathological results showed no metastasis. He was subsequently diagnosed with reactive lymphadenitis. The patient was discharged on postoperative day 4 in good condition and is alive without recurrence 12 months after surgery. PET/CT is useful for the detection of colorectal cancer recurrence; however, it does have a high false-positive rate for mediastinal lymph nodes. There is a limit to its diagnostic accuracy, and one must determine the indication for surgical treatment carefully. Surgery in the prone position is a useful and minimally invasive approach to the mediastinum and allows aggressive resection to be performed

Simultaneous Improvements in Performance and Durability of an Octahedral PtNix/C Electrocatalyst for Next-Generation Fuel Cells by Continuous, Compressive, and Concave Pt Skin Layers

Simultaneous improvements in oxygen reduction reaction (ORR) activity and long-term durability of Pt-based cathode catalysts are indispensable for the development of next-generation polymer electrolyte fuel cells but are still a major dilemma. We present a robust octahedral core–shell PtNix/C electrocatalyst with high ORR performance (mass activity and surface specific activity 6.8–16.9 and 20.3–24.0 times larger than those of Pt/C, respectively) and durability (negligible loss after 10000 accelerated durability test (ADT) cycles). The key factors of the robust octahedral nanostructure (core–shell Pt73Ni27/C) responsible for the remarkable activity and durability were found to be three continuous Pt skin layers with 2.0–3.6% compressive strain, concave facet arrangements (concave defects and high coordination), a symmetric Pt/Ni distribution, and a Pt67Ni33 intermetallic core, as found by STEM-EDS, in situ XAFS, XPS, etc. The robust core–shell Pt73Ni27/C was produced by the partial release of the stress, Pt/Ni rearrangement, and dimension reduction of an as-synthesized octahedral Pt50Ni50/C with 3.6–6.7% compressive Pt skin layers by Ni leaching during the activation process. The present results on the tailored synthesis of the PtNix structure and composition and the better control of the robust catalytic architecture renew the current knowledge and viewpoint for instability of octahedral PtNix/C samples to provide a new insight into the development of next-generation PEFC cathode catalysts

Detection of diurnal variation of tomato transcriptome through the molecular timetable method in a sunlight-type plant factory

The timing of measurement during plant growth is important because many genes are expressed periodically and orchestrate physiological events. Their periodicity is generated by environmental fluctuations as external factors and the circadian clock as the internal factor. The circadian clock orchestrates physiological events such as photosynthesis or flowering and it enables enhanced growth and herbivory resistance. These characteristics have possible applications for agriculture. In this study, we demonstrated the diurnal variation of the transcriptome in tomato (Solanum lycopersicum) leaves through molecular timetable method in a sunlight-type plant factory. Molecular timetable methods have been developed to detect periodic genes and estimate individual internal body time from these expression profiles in mammals. We sampled tomato leaves every 2 h for 2 days and acquired time-course transcriptome data by RNA-Seq. Many genes were expressed periodically and these expressions were stable across the 1st and 2nd days of measurement. We selected 143 time-indicating genes whose expression indicated periodically, and estimated internal time in the plant from these expression profiles. The estimated internal time was generally the same as the external environment time; however, there was a difference of more than 1 h between the two for some sampling points. Furthermore, the stress-responsive genes also showed weakly periodic expression, implying that they were usually expressed periodically, regulated by light–dark cycles as an external factor or the circadian clock as the internal factor, and could be particularly expressed when the plant experiences some specific stress under agricultural situations. This study suggests that circadian clock mediate the optimization for fluctuating environments in the field and it has possibilities to enhance resistibility to stress and floral induction by controlling circadian clock through light supplement and temperature control

Strong atomic ordering in Gd-doped GaN

Gd-doped GaN (Ga 1-xGd xN) thin films were grown on a GaN(001) template by radio frequency plasma-assisted molecular beam epitaxy and characterized by means of x-ray diffraction (XRD) and transmission electron microscopy (TEM). Three samples with a different Gd composition were prepared in this study: x = 0.02, 0.05, and 0.08. XRD and TEM results revealed that the low Gd concentration GaN possesses the wurtzite structure. On the other hand, it was found that an ordered phase with a quadruple-periodicity along the [001] direction in the wurtzite structure is formed throughout the film with x = 0.08. We proposed the atomistic model for the superlattice structure observed here. © 2012 American Institute of Physics.Manabu Ishimaru, Kotaro Higashi, Shigehiko Hasegawa, Hajime Asahi, Kazuhisa Sato, and Toyohiko J. Konno, "Strong atomic ordering in Gd-doped GaN", Appl. Phys. Lett. 101, 101912 (2012) https://doi.org/10.1063/1.4751245

Organosilica nanoparticles containing sodium borocaptate (BSH) provide new prospects for boron neutron capture therapy (BNCT): efficient cellular uptake and enhanced BNCT efficacy

Boron neutron capture therapy (BNCT), a method based on the fission of boron-10 upon neutron irradiation, has emerged as an attractive option for radiation therapy. To date, the main drugs used in BNCT are 4-boronophenylalanine (BPA) and sodium borocaptate (BSH). While BPA has been extensively tested in clinical trials, the use of BSH has been limited, mainly due to its poor cellular uptake. Here, we describe a novel type of mesoporous silica-based nanoparticle containing BSH covalently attached to a nanocarrier. Synthesis and characterization of these nanoparticles (BSH-BPMO) are presented. The synthetic strategy involves a click thiol–ene reaction with the boron cluster, providing hydrolytically stable linkage with the BSH in four steps. The BSH-BPMO nanoparticles were efficiently taken up into cancer cells and accumulated in the perinuclear region. Inductively coupled plasma (ICP) measurements of boron uptake in cells highlight the important role of the nanocarrier in the enhancement of boron internalization. BSH-BPMO nanoparticles were also taken up and distributed throughout tumour spheroids. BNCT efficacy was examined by the neutron exposure of the tumour spheroids. BSH-BPMO loaded spheroids were completely destroyed upon neutron irradiation. In contrast, neutron irradiation of tumour spheroids loaded with BSH or BPA resulted in significantly less spheroid shrinkage. The significant difference in BNCT efficacy of the BSH-BPMO was correlated with the improved boron uptake via the nanocarrier. Overall, these results demonstrate the critical role of the nanocarrier in BSH internalization and the enhanced BNCT efficacy of the BSH-BPMO compared with BSH and BPA, two drugs used in BNCT clinical trials

Key Structural Transformations and Kinetics of Pt Nanoparticles in PEFC Pt/C Electrocatalysts by a Simultaneous Operando Time-Resolved QXAFS–XRD Technique

This account article treats with the key structural transformations and kinetics of Pt nanoparticles in Pt/C cathode catalysts under transient voltage operations (0.4 VRHE→1.4 VRHE→0.4 VRHE) by simultaneous operando time-resolved QXAFS–XRD measurements, summarizing and analyzing our previous kinetic data in more detail and discussing on the key reaction steps and rate constants for the performance and durability of polymer electrolyte fuel cells (PEFC). The time-resolved QXAFS–XRD measurements were conducted at each acquisition time of 20 ms, while measuring the current/charge of the PEFC. The rate constants for the transient responses of Pt valence, CN(Pt–O) (CN: coordination number), CN(Pt–Pt), and Pt metallic-phase core size under the transient voltage operations were determined by the combined time-resolved QXAFS‒XRD technique. The relationship of the structural kinetics with the performance and durability of the PEFC Pt/C was also documented as key issues for the development of next-generation PEFCs. The present account emphasizes the time-resolved QXAFS and XRD techniques to be a powerful technique to analyze directly the structural and electronic change of metal nanoparticles inside PEFC under the operating conditions

再発性甲状腺癌のリンパ節転移におけるTc-99m MDPの集積(Tc-99m MDP Accumulation in Lymph Node Metastases of Recurrent Thyroid Cancer)(英語)

金沢医科大学 放射線科原著論文/症例報

Observation of Degradation of Pt and Carbon Support in Polymer Electrolyte Fuel Cell Using Combined Nano-X-ray Absorption Fine Structure and Transmission Electron Microscopy Techniques

It is hard to directly visualize spectroscopic and atomic–nanoscopic information on the degraded Pt/C cathode layer inside polymer electrolyte fuel cell (PEFC). However, it is mandatory to understand the preferential area, sequence, and relationship of the degradations of Pt nanoparticles and carbon support in the Pt/C cathode layer by directly observing the Pt/C cathode catalyst for the development of next-generation PEFC cathode catalysts. Here, the spectroscopic, chemical, and morphological visualization of the degradation of Pt/C cathode electrocatalysts in PEFC was performed successfully by a same-view combination technique of nano-X-ray absorption fine structure (XAFS) and transmission electron microscopy (TEM)/scanning TEM–energy-dispersive spectrometry (EDS) under a humid N2 atmosphere. The same-view nano-XAFS and TEM/STEM–EDS imaging of the Pt/C cathode of PEFC after triangular-wave 1.0–1.5 VRHE (startup/shutdown) accelerated durability test (tri-ADT) cycles elucidated the site-selective area, sequence, and relationship of the degradations of Pt nanoparticles and carbon support in the Pt/C cathode layer. The 10 tri-ADT cycles caused a carbon corrosion to reduce the carbon size preferentially in the boundary regions of the cathode layer with both electrolyte and holes/cracks, accompanied with detachment of Pt nanoparticles from the degraded carbon. After the decrease in the carbon size to less than 8 nm by the 20 tri-ADT cycles, Pt nanoparticles around the extremely corroded carbon areas were found to transform and dissolve into oxidized Pt2+–O4 species

Confined Single Alkali Metal Ion Platform in a Zeolite Pore for Concerted Benzene C–H Activation to Phenol Catalysis

The well-known cumene process via an explosive cumene hydroperoxide intermediate in liquid phase currently employed for phenol production is energy-intensive and not environmentally friendly. Therefore, there is a demand for an alternative single-step gas-phase catalysis process. According to the conventional catalysis concept, selective oxidation reactions are promoted by redox catalysts and not by acid–base catalysts. In general, alkali and alkaline earth metal ions cannot activate each of benzene, O2, and N2O when they adsorb separately. However, we observed an unprecedented catalysis of single alkali and alkaline earth metal ion sites incorporated into zeolite pores for the selective oxidation of benzene to phenol with N2O and O2 + NH3, thereby providing a single-site catalytic platform with high selectivity. Among alkali and alkaline earth metal ions, single Cs+ and Rb+ sites with ion diameters of >300 pm in the pores of β-zeolites exhibited remarkable selectivity for benzene C–H activation to phenol catalysis in a concerted reaction pathway

Operando Imaging of Ce Radical Scavengers in a Practical Polymer Electrolyte Fuel Cell by 3D Fluorescence CT–XAFS and Depth-Profiling Nano-XAFS–SEM/EDS Techniques

There is little information on the spatial distribution, migration, and valence of Ce species doped as an efficient radical scavenger in a practical polymer electrolyte fuel cell (PEFC) for commercial fuel cell vehicles (FCVs) closely related to a severe reliability issue for long-term PEFC operation. An in situ three-dimensional fluorescence computed tomography–X-ray absorption fine structure (CT–XAFS) imaging technique and an in situ same-view nano-XAFS–scanning electron microscopy (SEM)/energy-dispersive spectrometry (EDS) combination technique were applied for the first time to perform operando spatial visualization and depth-profiling analysis of Ce radical scavengers in a practical PEFC of Toyota MIRAI FCV under PEFC operating conditions. Using these in situ techniques, we successfully visualized and analyzed the domain, density, valence, and migration of Ce scavengers that were heterogeneously distributed in the components of PEFC, such as anode microporous layer, anode catalyst layer, polymer electrolyte membrane (PEM), cathode catalyst layer, and cathode microporous layer. The average Ce valence states in the whole PEFC and PEM were 3.9+ and 3.4+, respectively, and the Ce³⁺/Ce⁴⁺ ratios in the PEM under H₂ (anode)–N₂ (cathode) at an open-circuit voltage (OCV), H₂–air at 0.2 A cm⁻², and H₂–air at 0.0 A cm⁻² were 70 ± 5:30 ± 5%, as estimated by both in situ fluorescence CT–X-ray absorption near-edge spectroscopy (XANES) and nano-XANES–SEM/EDS techniques. The Ce³⁺ migration rates in the electrolyte membrane toward the anode and cathode electrodes ranged from 0.3 to 3.8 μm h⁻¹, depending on the PEFC operating conditions. Faster Ce³⁺ migration was not observed with voltage transient response processes by highly time-resolved (100 ms) and spatially resolved (200 nm) nano-XANES imaging. Ce³⁺ ions were suggested to be coordinated with both Nafion sulfonate (Nf_sul) groups and water to form [Ce(Nf_sul)_x(H₂O)_y]³⁺. The Ce migration behavior may also be affected by the spatial density of Ce, interactions of Ce with Nafion, thickness and states of the PEM, and H₂O convection, in addition to the PEFC operating conditions. The unprecedented operando imaging of Ce radical scavengers in the practical PEFCs by both in situ three-dimensional (3D) fluorescence CT–XAFS imaging and in situ depth-profiling nano-XAFS–SEM/EDS techniques yields intriguing insights into the spatial distribution, chemical states, and behavior of Ce scavengers under the working conditions for the development of next-generation PEFCs with high long-term reliability and durability