Low-Temperature Methane Combustion Using Ozone over Coß Catalyst.

Catalytic methane (CH4) combustion is a promising approach to reducing the release of unburned methane in exhaust gas. Here, we report Co-exchanged ß zeolite (Coß) as an efficient catalyst for CH4 combustion using O3. A series of ion-exchanged ß zeolites (Co, Ni, Mn, Fe, and Pd) are subjected to the catalytic test, and Coß exhibits a superior performance in a low-temperature region (<100 °C). The results of X-ray absorption spectroscopy (XAS) and catalytic tests for Coß with different Co loadings indicate the isolated Co species is the plausible active site. The reaction mechanism of CH4 combustion over the isolated Co2+ cation is theoretically investigated by the single-component artificial force-induced reaction (SC-AFIR) method to thoroughly search for possible reaction routes. The resulting path toward CO2 formation shows an activation energy of 73 kJ/mol for the rate-determining step and an exothermicity of 1025 kJ/mol, which supports the experimental results. During a long-term catalytic test for 160 h without external heating, the CH4 conversion gradually decreases from 80 to 40%, but the conversion fully recovers after dehydration at 500 °C (0.5 h). The copresence of H2O and CO exhibits a negative impact on the catalytic activity, while NO and SO2 do not markedly change the catalytic activity.

Designing main-group catalysts for low-temperature methane combustion by ozone.

The catalytic combustion of methane at a low temperature is becoming increasingly key to controlling unburned CH4 emissions from natural gas vehicles and power plants, although the low activity of benchmark platinum-group-metal catalysts hinders its broad application. Based on automated reaction route mapping, we explore main-group elements catalysts containing Si and Al for low-temperature CH4 combustion with ozone. Computational screening of the active site predicts that strong Brønsted acid sites are promising for methane combustion. We experimentally demonstrate that catalysts containing strong Bronsted acid sites exhibit improved CH4 conversion at 250 °C, correlating with the theoretical predictions. The main-group catalyst (proton-type beta zeolite) delivered a reaction rate that is 442 times higher than that of a benchmark catalyst (5 wt% Pd-loaded Al2O3) at 190 °C and exhibits higher tolerance to steam and SO2. Our strategy demonstrates the rational design of earth-abundant catalysts based on automated reaction route mapping.

Sperm function and oxidative status: Effect on fertility in Bos taurus and Bos indicus bulls when semen is used for fixed-time artificial insemination.

Semen quality is one of the criteria used for the selection of bulls with relatively greater fertility. In addition, bull fertility depends on the integrity and function of all sperm structures. The aim of this study, therefore, was to determine associations when there was conducting of conventional and functional techniques for the evaluation of sperm samples from bulls with known fertility history as determined when semen from these bulls was used for fixed-time artificial insemination programs. The study was designed in a 2 × 2 factorial arrangement, with one factor being breed (Angus x Nellore) and the other fertility (greater x lesser). Greater fertility groups were composed of ten Angus and 11 Nellore bulls, while lesser fertility groups were composed of ten Angus and seven Nellore bulls. Sperm were analyzed, in four cryopreserved distinct batches for each animal, for morphology, kinetics, plasma and acrosomal membrane integrity, mitochondrial activity and mitochondrial membrane potential, DNA integrity and oxidative status. There was no difference in characteristics commonly used in sperm quality conventional analysis. The results from functional analysis indicated an important association between mitochondrial dysfunctions, oxidative stress, and damage to sperm structures in lesser fertility bulls. Greater fertility bulls had greater sperm quality and indicators of functional cell structures. The associations, when there were evaluations using different techniques, indicate the importance of evaluation and correlation between different sperm functions to understand effects of distinct parameters on sperm fertilization capacity.

Collective pattern formations of animals in active matter physics.

Active matter refers to systems composed of elements that are self-propelled by the dissipation of energy, in which dynamical patterns emerge, as is the case of flocks of birds and schools of fish. Some researchers in active matter physics seek to identify unified descriptions of such collective motions through interdisciplinary approaches by biologists and physicists. Through such collaborations, experimental studies pertaining to active matter physics have been developing recently, which allow us to verify the proposed mathematical models. Here, we review collective pattern formations and behaviors of animals from the perspective of active matter physics.

Hydroxy-selenomethionine as an organic source of selenium in the diet improves boar reproductive performance in artificial insemination programs.

This study aimed to compare different selenium (Se) sources in the diet on boar's semen quality and fertility. For this, 28 boars aged 8 to 28 mo were fed with the following dietary treatments for 95 d: 0.3 mg Se/kg as sodium selenite (SS; n = 14) and 0.3 mg Se/kg as hydroxy-selenomethionine (OH-SeMet; n = 14). During this period, two experiments were carried out. In experiment 1, the semen of all boars was evaluated every 2 wk. Raw semen was initially evaluated for the processing of seminal doses, which were stored at 17 °C for 72 h, followed by sperm quality assessments. Furthermore, Se concentration and glutathione peroxidase (GPx) activity were measured in the seminal plasma. In experiment 2, 728 females were inseminated weekly with seminal doses from boars of the different experimental groups to further assess in vivo fertility and litter characteristics. Results demonstrated that boars fed OH-SeMet had more Se in their seminal plasma (P < 0.05), showing the greater bioavailability of the organic source in the male reproductive system. Moreover, boars fed OH-SeMet tended (P < 0.10) toward a higher total sperm count in the ejaculate (66.60 vs. 56.57 × 109 sperm) and the number of seminal doses (22.11 vs. 18.86; 3 × 109 sperm/dose) when compared with those fed SS. No effect of the dietary treatments was observed on GPx activity in seminal plasma (P > 0.05) as well as on raw and stored semen quality (P > 0.05). Under in vivo conditions, seminal doses from boars fed OH-SeMet tended (P < 0.10) toward a higher pregnancy rate at weeks 3, 5, and 8, and also resulted in a higher (P < 0.05) percentage of pregnant females in the overall period (99.30 vs. 97.00). In conclusion, the replacement of SS with OH-SeMet in boars' diet can improve sperm production and results in better reproductive performance for them, bringing greater productivity and profitability to artificial insemination centers and commercial pig farms.

C. elegans collectively forms dynamical networks.

Understanding physical rules underlying collective motions requires perturbation of controllable parameters in self-propelled particles. However, controlling parameters in animals is generally not easy, which makes collective behaviours of animals elusive. Here, we report an experimental system in which a conventional model animal, Caenorhabditis elegans, collectively forms dynamical networks of bundle-shaped aggregates. We investigate the dependence of our experimental system on various extrinsic parameters (material of substrate, ambient humidity and density of worms). Taking advantage of well-established C. elegans genetics, we also control intrinsic parameters (genetically determined motility) by mutations and by forced neural activation via optogenetics. Furthermore, we develop a minimal agent-based model that reproduces the dynamical network formation and its dependence on the parameters, suggesting that the key factors are alignment of worms after collision and smooth turning. Our findings imply that the concepts of active matter physics may help us to understand biological functions of animal groups.

Controlled Construction of Stable Network Structure Composed of Honeycomb-Shaped Microhydrogels.

Recently, the construction of models for multicellular systems such as tissues has been attracting great interest. These model systems are expected to reproduce a cell communication network and provide insight into complicated functions in living systems./Such network structures have mainly been modelled using a droplet and a vesicle. However, in the droplet and vesicle network, there are difficulties attributed to structural instabilities due to external stimuli and perturbations. Thus, the fabrication of a network composed of a stable component such as hydrogel is desired. In this article, the construction of a stable network composed of honeycomb-shaped microhydrogels is described. We produced the microhydrogel network using a centrifugal microfluidic technique and a photosensitive polymer. In the network, densely packed honeycomb-shaped microhydrogels were observed. Additionally, we successfully controlled the degree of packing of microhydrogels in the network by changing the centrifugal force. We believe that our stable network will contribute to the study of cell communication in multicellular systems.

Collective motion of rod-shaped self-propelled particles through collision.

Self-propelled rods, which propel by themselves in the direction from the tail to the head and align nematically through collision, have been well-investigated theoretically. Various phenomena including true long-range ordered phase with the Giant number fluctuations, and the collective motion composed of many vorices were predicted using the minimal mathematical models of self-propelled rods. Using filamentous bacteria and running microtubules, we found that the predicted phenomena by the minimal models occur in the real world. This strongly indicates that there exists the unified description of self-propelled rods independent of the details of the systems. The theoretically predicted phenomena and the experimental results concerning the phenomena are reviewed.

Lateral Tension-Induced Penetration of Particles into a Liposome.

It is important that we understand the mechanism of the penetration of particles into a living cell to achieve advances in bionanotechnology, such as for treatment, visualization within a cell, and genetic modification. Although there have been many studies on the application of functional particles to cells, the basic mechanism of penetration across a biological membrane is still poorly understood. Here we used a model membrane system to demonstrate that lateral membrane tension drives particle penetration across a lipid bilayer. After the application of osmotic pressure, fully wrapped particles on a liposome surface were found to enter the liposome. We discuss the mechanism of the tension-induced penetration in terms of narrow constriction of the membrane at the neck part. The present findings are expected to provide insight into the application of particles to biological systems.

Long-range nematic order and anomalous fluctuations in suspensions of swimming filamentous bacteria.

We study the collective dynamics of elongated swimmers in a very thin fluid layer by devising long filamentous nontumbling bacteria. The strong confinement induces weak nematic alignment upon collision, which, for large enough density of cells, gives rise to global nematic order. This homogeneous but fluctuating phase, observed on the largest experimentally accessible scale of millimeters, exhibits the properties predicted by standard models for flocking, such as the Vicsek-style model of polar particles with nematic alignment: true long-range nematic order and nontrivial giant number fluctuations.

Photoinduced Fusion of Lipid Bilayer Membranes.

We have developed a novel system for photocontrol of the fusion of lipid vesicles through the use of a photosensitive surfactant containing an azobenzene moiety (AzoTAB). Real-time microscopic observations clarified a change in both the surface area and internal volume of vesicles during fusion. We also determined the optimal cholesterol concentrations and temperature for inducing fusion. The mechanism of fusion can be attributed to a change in membrane tension, which is caused by the solubilization of lipids through the isomerization of AzoTAB. We used a micropipet technique to estimate membrane tension and discuss the mechanism of fusion in terms of membrane elastic energy. The obtained results regarding this novel photoinduced fusion could lead to a better understanding of the mechanism of membrane fusion in living cells and may also see wider applications, such as in drug delivery and biomimetic material design.

Lateral Diffusion of a Submicrometer Particle on a Lipid Bilayer Membrane.

In past decades, nanoparticles and nanomaterials have been actively used for applications such as visualizing nano/submicrometer cell structure, killing cancer cells, and using drug delivery systems. It is important to understand the physicochemical mechanisms that govern the motion of nanoparticles on a plasma membrane surface. However, the motion of small particles of <1000 nm on lipid membranes is poorly understood. In this study, we investigated the diffusion of particles with a diameter of 200-800 nm on a lipid membrane using cell-sized liposomes. Particle-associated liposomes were obtained by applying centrifugal force to a mixture of liposomes and particle solutions. We measured the thermal motion of the particles by phase-contrast microscopy. We found that (i) the particle-size dependence of the diffusion of particles adhering to membranes was better described by the DADL model rather than the Einstein-Stokes model, (ii) the diffusion coefficient of a particle strongly depends on the adsorption state of the particle, such as fully or partially wrapped by the membrane, and (iii) anomalous diffusion was induced by the localization of particles on the neck of budded vesicles.

Mathematical model for self-propelled droplets driven by interfacial tension.

We propose a model for the spontaneous motion of a droplet induced by inhomogeneity in interfacial tension. The model is derived from a variation of the Lagrangian of the system and we use a time-discretized Morse flow scheme to perform its numerical simulations. Our model can naturally simulate the dynamics of a single droplet, as well as that of multiple droplets, where the volume of each droplet is conserved. We reproduced the ballistic motion and fission of a droplet, and the collision of two droplets was also examined numerically.

Complex-shaped three-dimensional multi-compartmental microparticles generated by diffusional and Marangoni microflows in centrifugally discharged droplets.

We report a versatile method for the generation of complex-shaped three-dimensional multi-compartmental (3D-MC) microparticles. Complex-shaped microparticles have recently received much attention for potential application in self-assemblies, micromachines, and biomedical and environmental engineering. Here, we have developed a method based on 3D nonequilibrium-induced microflows (Marangoni and diffusional flows) of microdroplets that are discharged from the tip of a thin capillary in a simple centrifugal microfluidic device. The microparticle shapes can be tuned by the partial dissolution of specific compartments and by the deformation of the precursor microdroplets by manipulating the 3D microflows. We believe that this method will have wide applications in nano- and microscience and technologies.

Methotrexate-related lymphoproliferative disorder of the stomach in a patient with rheumatoid arthritis: a case of disease regression after methotrexate cessation.

We report the case of a 78-year-old woman with methotrexate-related gastric lymphoproliferative disorder (LPD). The patient had a history of rheumatoid arthritis (RA) and had been treated with methotrexate (MTX). Endoscopic examination revealed round elevated lesions in the stomach, and a biopsy specimen showed atypical lymphoid cell proliferation. Immunohistological study found these atypical cells to be positive for L-26 but not for CD3 or EBER. Therefore, we made a diagnosis of MTX-related LPD showing features of diffuse large B-cell lymphoma. Combined positron emission tomography-computed tomography (PET-CT) using 18F-fluorodeoxyglucose (FDG) showed increased avidity in the stomach in addition to slightly increased FDG-avidity in the mediastinum and left chest wall. We decided not to start chemotherapy but to discontinue administration of MTX, with follow-up using endoscopy and PET-CT. The endoscopic examinations after cessation of MTX demonstrated gradual regression of the elevated lesions. PET-CT 6 months after cessation showed no increased FDG avidity in the stomach. While disease regression was observed in the stomach, the other FDG-avid spots remained unchanged on PET-CT. Therefore, we performed chemotherapy as additional therapy. On PET-CT after chemotherapy, the FDG-avid spots remained unchanged for more than 1 year, and we eventually concluded that they were RA-related inflammatory lesions. In patients with MTX-related LPD, cessation of MTX may be a therapeutic option, but careful follow-up and chemotherapy in accordance with the clinical course are essential.

Influence of Asymmetry and Driving Forces on the Propulsion of Bubble-Propelled Catalytic Micromotors.

Bubble-propelled catalytic micromotors have recently been attracting much attention. A bubble-propulsion mechanism has the advantage of producing a stronger force and higher speed than other mechanisms for catalytic micromotors, but the nature of the fluctuated bubble generation process affects the motions of the micromotors, making it difficult to control their motions. Thus, understanding of the influence of fluctuating bubble propulsion on the motions of catalytic micromotors is important in exploiting the advantages of bubble-propelled micromotors. Here, we report experimental demonstrations of the bubble-propelled motions of propeller-shaped micromotors and numerical analyses of the influence of fluctuating bubble propulsion on the motions of propeller-shaped micromotors. We found that motions such as trochoid-like motion and circular motion emerged depending on the magnitude or symmetricity of fluctuations in the bubble-propulsion process. We hope that those results will help in the construction and application of sophisticated bubble-propelled micromotors in the future.

Collective motion of self-propelled particles with memory.

We show that memory, in the form of underdamped angular dynamics, is a crucial ingredient for the collective properties of self-propelled particles. Using Vicsek-style models with an Ornstein-Uhlenbeck process acting on angular velocity, we uncover a rich variety of collective phases not observed in usual overdamped systems, including vortex lattices and active foams. In a model with strictly nematic interactions the smectic arrangement of Vicsek waves giving rise to global polar order is observed. We also provide a calculation of the effective interaction between vortices in the case where a telegraphic noise process is at play, explaining thus the emergence and structure of the vortex lattices observed here and in motility assay experiments.

[Hepatic Resection of Multiple Liver Metastases from Gastric Cancer after Molecular Targeted Chemotherapy(S-1 plus Cisplatin plus Trastuzumab)].

A 62-year-old man was diagnosed with gastric cancer and underwent distal gastrectomy, and D1+b lymph node dissection. He was diagnosed postoperatively with T1b (sm2) N0M0, StageⅠA gastric adenocarcinoma and did not receive any adjuvant chemotherapy after surgery. One year and 6 months after gastrectomy, blood analysis indicated high levels of carcinoembryonic antigen (CEA 262.1 ng/mL) while abdominal computed tomography (CT) revealed multiple liver tumors (S7: 15 mm, S7/8: 20 mm). The patient was diagnosed with metachronous multiple liver metastases from gastric cancer. Chemotherapy, combined with molecular targeted therapy (S-1 plus cisplatin [CDDP] plus trastuzumab), was administered because of overexpression of the human epidermal growth factor receptor 2 (HER2) protein in the primary tumor as assessed by immunohistochemistry, the CEA levels decreased immediately after 2 cycles of the chemotherapy, and the liver metastases shrank markedly with no evidence of new lesions on abdominal CT. However, after treatment, Grade 3 neutropenia and diarrhea were observed. Chemotherapy was suspended and hepatic resection was performed. After hepatic resection, the liver tumors were histologically evaluated as Grade 2 metastatic gastric adenocarcinoma, and the HER2 expression of remnant carcinoma cells was established. The patient has been in good health and remained free of recurrences in the 2 years and 3 months after the liver resection. Surgery with preoperative chemotherapy (S-1 plus CDDP plus trastuzumab) can be an effective treatment for liver metastasis from HER2-positive gastric cancer.

[A Case of HER2-Positive Advanced Gastric Cancer with a Pathological Complete Response to Neoadjuvant Chemotherapy with S-1/CDDP/Trastuzumab].

A 61-year-old man was referred to our hospital because of epigastric pain. Upper gastrointestinal endoscopy revealed a type 2 tumor at the gastric antrum, which was diagnosed as gastric adenocarcinoma (tub1) by pathological examination and was HER2 positive 3+ by the IHC method. Abdominal computed tomography revealed multiple metastases to regional lymph nodes (LNs), including bulky nodes at No. 3, 6, and 11p stations. In particular, No. 6 LN was 43 mm in diameter and had invaded to the pancreas. The clinical stage was Ⅲc (T4aN3M0) and neoadjuvant chemotherapy was conducted using S-1/CDDP/trastuzumab. After 2 cycles of chemotherapy, a partial clinical response was obtained and distal gastrectomy with LN dissection (D2 plus No. 16 LN) was performed. The pathological specimens showed no residual cancer cells in the stomach and LNs (Grade 3: pCR). Adjuvant chemotherapy was not administered. The patient is alive 10 months after the surgery with no evidence of recurrence.

[A Case of Conversion Surgery after Long-Term Chemotherapy for Advanced Gastric Carcinoma with Synchronous Distant Metastasis].

We report the case of a patient who underwent conversion surgery after long-term chemotherapy for advanced gastric carcinoma with synchronous distant metastasis. She was admitted to our hospital because of back pain and elevated serum ALP level. Gastrointestinal endoscopy showed multiple 0-Ⅱa like lesions at the gastric antrum, and a biopsy specimen showed poorly differentiated adenocarcinoma negative for HER2. Colonoscopy showed a submucosal tumor at the cecum, and pathological examination revealed metastatic gastric adenocarcinoma. CT revealed regional lymph node metastasis, bilateral ovarian tumors, and systemic bone absorption indicating metastasis. Systemic chemotherapy with cisplatin and S-1 was carried out, and complete resolution of gastric and colic lesions was obtained. Afterwards, a new gastric lesion appeared with re-growth of regional lymph nodes and bilateral ovarian tumors. Distal gastrectomy with D2 dissection and bilateral ovariectomy was performed 2 years 6 months after the initial therapy. Although systemic chemotherapy is the standard treatment for advanced gastric carcinoma with distant metastasis, surgical resection can be justified when drug-resistant lesions are localized and conversion surgery is feasible. Postoperative chemotherapy is mandatory to prolong survival.