Showing papers by "Kyoto University published in 2022"

Steam explosion of lignocellulosic biomass for multiple advanced bioenergy processes: A review

Abstract: The utilization of lignocellulosic biomass to produce fuels and chemicals is an effective way to gradually relieve the global threats of petroleum exhaustion and climate change. However, the recalcitrant nature and complex structure of biomass have become the biggest obstacle for utilization during the bioenergy conversion processes. Steam explosion, a mild and fast treatment process integrating the high-temperature autohydrolysis and structural disruption by explosive decompression, has been proven as an effective, environment-friendly and industrially scalable method for biomass pretreatment, which can significantly improve the fuel properties and processability of the feedstock, for several bioenergy conversion techniques. This article aimed at reviewing the impact of steam explosion pretreatment on the bioenergy conversion processes and product properties. Based on those findings in the literature, a steam explosion step is beneficial to subsequent conversion processes of biomass, including densification, hydrolysis, fermentation, pyrolysis and gasification, by improving biomass properties such as durability, heating value and cellulose accessibility. Improved yields and properties of final products in solid (e.g. pellet fuel, biochar), liquid (e.g. bio-oil, bioethanol, biobutanol) and gaseous (e.g. syngas, biogas) states were also analyzed. Overall, this review provided a historical and comprehensive understanding of how the steam explosion benefits the subsequent bioenergy conversion process and product quality.

Cell transcriptomic atlas of the non-human primate Macaca fascicularis

Abstract: Studying tissue composition and function in non-human primates (NHPs) is crucial to understand the nature of our own species. Here we present a large-scale cell transcriptomic atlas that encompasses over 1 million cells from 45 tissues of the adult NHP Macaca fascicularis. This dataset provides a vast annotated resource to study a species phylogenetically close to humans. To demonstrate the utility of the atlas, we have reconstructed the cell-cell interaction networks that drive Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases, and intersected our data with human genetic disease orthologues to establish potential clinical associations. Our M. fascicularis cell atlas constitutes an essential reference for future studies in humans and NHPs.

Recent Progress on Mixed-Anion Materials for Energy Applications

Abstract: Mixed-anion compounds, in which multiple anions such as O2−, N3−, and H− are contained in the same compound, have recently attracted attention. Because mixed-anion compounds have a unique crystal structure with multiple anions coordinated to cations, materials with fundamentally new and innovative functions are expected to be developed for various chemistry and physics applications, including catalysts, batteries, and superconductors. In this Account, recent progress in the development of new mixed-anion compounds by the MEXT mixed-anion project is described, with emphasis on results related to the development of materials used as photocatalysts/photoelectrodes, phosphors, secondary battery components, conductors, and thermoelectric materials. Mixed-anion compounds containing more than one anionic species in the same phase can exhibit emergent properties and/or functions that are unattainable with their single-anion counterparts. This Account describes recent progress in the development of new mixed-anion compounds for various applications related to energy, with emphasis on our interdisciplinary collaboration in a national project on mixed-anion materials.

Cascaded energy landscape as a key driver for slow yet efficient charge separation with small energy offset in organic solar cells

Abstract: We examined the mechanisms underlying the free carrier generation in a very topical PM6/Y6 organic solar cell. We observed slow yet efficient spatial charge dissociation driven by downhill energy relaxation through the interfacial energy cascade.

CD153/CD30 signaling promotes age-dependent tertiary lymphoid tissue expansion and kidney injury

Abstract: Tertiary lymphoid tissues (TLTs) facilitate local T and B cell interactions in chronically inflamed organs. However, the cells and molecular pathways that govern TLT formation are poorly defined. Here, we identified TNF superfamily CD153/CD30 signaling between 2 unique age-dependent lymphocyte subpopulations, CD153+PD-1+CD4+ senescence-associated T (SAT) cells and CD30+T-bet+ age-associated B cells (ABCs), as a driver for TLT expansion. SAT cells, which produced ABC-inducing factors IL-21 and IFN-γ, and ABCs progressively accumulated within TLTs in aged kidneys after injury. Notably, in kidney injury models, CD153 or CD30 deficiency impaired functional SAT cell induction, which resulted in reduced ABC numbers and attenuated TLT formation with improved inflammation, fibrosis, and renal function. Attenuated TLT formation after transplantation of CD153-deficient bone marrow further supported the importance of CD153 in immune cells. Clonal analysis revealed that SAT cells and ABCs in the kidneys arose from both local differentiation and recruitment from the spleen. In the synovium of aged rheumatoid arthritis patients, T peripheral helper/T follicular helper cells and ABCs also expressed CD153 and CD30, respectively. Together, our data reveal a previously unappreciated function of CD153/CD30 signaling in TLT formation and propose targeting the CD153/CD30 signaling pathway as a therapeutic target for slowing kidney disease progression.

First gadolinium loading to Super-Kamiokande

Abstract: In order to improve Super-Kamiokande’s neutron detection efficiency and to thereby increase its sensitivity to the diffuse supernova neutrino background flux, 13 tons of Gd2(SO4)3⋅8H2O (gadolinium sulfate octahydrate) was dissolved into the detector’s otherwise ultrapure water from July 14 to August 17, 2020, marking the start of the SK-Gd phase of operations. During the loading, water was continuously recirculated at a rate of 60 m3/h, extracting water from the top of the detector and mixing it with concentrated Gd2(SO4)3⋅8H2O solution to create a 0.02% solution of the Gd compound before injecting it into the bottom of the detector. A clear boundary between the Gd-loaded and pure water was maintained through the loading, enabling monitoring of the loading itself and the spatial uniformity of the Gd concentration over the 35 days it took to reach the top of the detector. During the subsequent commissioning the recirculation rate was increased to 120 m3/h, resulting in a constant and uniform distribution of Gd throughout the detector and water transparency equivalent to that of previous pure-water operation periods. Using an Am–Be neutron calibration source the mean neutron capture time was measured to be 115±1 μs, which corresponds to a Gd concentration of 111±2 ppm, as expected for this level of Gd loading. This paper describes changes made to the water circulation system for this detector upgrade, the Gd loading procedure, detector commissioning, and the first neutron calibration measurements in SK-Gd.

Porphyrinoids, a unique platform for exploring excited-state aromaticity

Abstract: Recently, Baird (anti)aromaticity has been referred to as a description of excited-state (anti)aromaticity. With the term of Baird's rule, recent studies have intensively verified that the Hückel aromatic [4n + 2]π (or antiaromatic [4n]π) molecules in the ground state are reversed to give Baird aromatic [4n]π (or Baird antiaromatic [4n + 2]π) molecules in the excited states. Since the Hückel (anti)aromaticity has great influence on the molecular properties and reaction mechanisms, the Baird (anti)aromaticity has been expected to act as a dominant factor in governing excited-state properties and processes, which has attracted intensive scientific investigations for the verification of the concept of reversed aromaticity in the excited states. In this scientific endeavor, porphyrinoids have recently played leading roles in the demonstration of the aromaticity reversal in the excited states and its conceptual development. The distinct structural and electronic nature of porphyhrinoids depending on their (anti)aromaticity allow the direct observation of excited-state aromaticity reversal, Baird's rule. The explicit experimental demonstration with porphyrinoids has contributed greatly to its conceptual development and application in novel functional organic materials. Based on the significant role of porphyrinoids in the field of excited-state aromaticity, this review provides an overview of the experimental verification of the reversal concept of excited-state aromaticity by porphyrinoids and the recent progress on its conceptual application in novel functional molecules.

Advanced Tertiary Lymphoid Tissues in Protocol Biopsies are Associated with Progressive Graft Dysfunction in Kidney Transplant Recipients

Abstract: Tertiary lymphoid tissues (TLTs) are ectopic lymphoid tissues found in chronically inflamed organs. Although studies have documented TLT formation in transplanted kidneys, the clinical relevance of these TLTs remains controversial. We examined the effects of TLTs on future graft function using our histologic TLT maturity stages and the association between TLTs and Banff pathologic scores. We also analyzed the risk factors for the development of TLTs.Serial protocol biopsy samples (0 hour, 1, 6, and 12 months) without rejection were retrospectively analyzed from 214 patients who underwent living donor kidney transplantation. TLTs were defined as lymphocyte aggregates with signs of proliferation and their stages were determined by the absence (stage I) or presence (stage II) of follicular dendritic cells.Only 4% of patients exhibited TLTs at the 0-hour biopsy. Prevalence increased to almost 50% at the 1-month biopsy, and then slightly further for 12 months. The proportion of advanced stage II TLTs increased gradually, reaching 19% at the 12-month biopsy. Presence of stage II TLTs was associated with higher risk of renal function decline after transplantation compared with patients with no TLT or stage I TLTs. Stage II TLTs were associated with more severe tubulitis and interstitial fibrosis/tubular atrophy at 12 months and predicted poorer graft function independently from the degree of interstitial inflammation. Pretransplantation rituximab treatment dramatically attenuated the development of stage II TLTs.TLTs are commonly found in clinically stable transplanted kidneys. Advanced stage II TLTs are associated with progressive graft dysfunction, independent of interstitial inflammation.

Traditional Chinese medicine for precancerous lesions of gastric cancer: A review

Abstract: Gastric cancer (GC) is the fifth most common type of cancer and the third leading cause of death due to cancer worldwide. The gastric mucosa often undergoes many years of precancerous lesions of gastric cancer (PLGC) stages before progressing to gastric malignancy. Unfortunately, there are no effective Western drugs for patients with PLGC. In recent years, traditional Chinese medicine (TCM) has been proven effective in treating PLGC. Classical TCM formulas and chemical components isolated from some Chinese herbal medicines have been administered to treat PLGC, and the main advantage is their comprehensive intervention with multiple approaches and multiple targets. In this review, we focus on recent studies using TCM treatment for PLGC, including clinical observations and experimental research, with a focus on targets and mechanisms of drugs. This review provides some ideas and a theoretical basis for applying TCM to treat PLGC and prevent GC.

Emergence of Copper(I/II) Complexes as Third-Generation Redox Shuttles for Dye-Sensitized Solar Cells

Abstract: Redox shuttles play a crucial role in the photovoltaic performance of dye-sensitized solar cells (DSSCs). A traditional iodide/triiodide (I–/I3–) redox shuttle has been widely utilized in the first generation, but it suffers from intrinsic disadvantages such as a limited open-circuit voltage (VOC). On the other hand, cobalt(II/III) complexes with polypyridyl ligands have been established as second-generation redox shuttles and have achieved a power conversion efficiency (η) of up to 13%. Since 2016, copper(I/II) complexes have appeared as third-generation redox shuttles owing to their more positive redox potentials. The η values of the copper-based DSSCs were low in the early stages, but to date, they have reached up to 13% as a result of modulating the molecular structures of the copper complexes and sensitizers. In this Perspective, recent developments in and prospects for copper-based DSSCs are highlighted, toward over 15% power conversion efficiency.

Minimum entropy production, detailed balance and Wasserstein distance for continuous-time Markov processes

Abstract: We investigate the problem of minimizing the entropy production for a physical process that can be described in terms of a Markov jump dynamics. We show that, without any further constraints, a given time-evolution may be realized at arbitrarily small entropy production, yet at the expense of diverging activity. For a fixed activity, we find that the dynamics that minimizes the entropy production is given in terms of conservative forces. The value of the minimum entropy production is expressed in terms of the graph-distance based Wasserstein distance between the initial and final configuration. This yields a new kind of speed limit relating dissipation, the average number of transitions and the Wasserstein distance. It also allows us to formulate the optimal transport problem on a graph in term of a continuous-time interpolating dynamics, in complete analogy to the continuous space setting. We demonstrate our findings for simple state networks, a time-dependent pump and for spin flips in the Ising model.

Adverse events during intrahospital transport of critically ill patients: A systematic review and meta-analysis.

Abstract: Introduction Intrahospital transport of critically ill patients is often necessary for diagnostic procedures, therapeutic procedures, or admission to the intensive care unit. The aim of this study was to investigate and describe safety and adverse events during intrahospital transport of critically ill patients. Material and methods A systematic search was performed of MEDLINE and the Cochrane Central Register of Controlled Trials for studies published up to June 3, 2020, and of the International Clinical Trials Platform Search Portal and ClinicalTrials.gov for ongoing trials. We selected prospective and retrospective cohort studies published in English on intrahospital transport of critically ill patients, and then performed a meta-analysis. The primary outcome was the incidence of all adverse events that occurred during intrahospital transport. The secondary outcomes were death due to intrahospital transport or life-threatening adverse events, minor events in vital signs, adverse events related to equipment, durations of ICU and hospital stay, and costs. Results A total of 12,313 intrahospital transports and 1898 patients from 24 studies were included in the meta-analysis. Among 24 studies that evaluated the primary outcome, the pooled frequency of all adverse events was 26.2% (95% CI: 15.0–39.2) and the heterogeneity among these studies was high (I2 = 99.5%). The pooled frequency of death due to intrahospital transport and life-threatening adverse events was 0% and 1.47% each, but heterogeneity was also high. Conclusions Our findings suggest that adverse events can occur during intrahospital transport of critically ill patients, and that the frequency of critical adverse events is relatively low. The results of this meta-analysis could assist in risk-benefit analysis of diagnostic or therapeutic procedures requiring intrahospital transport of critically ill patients. Trial registration: UMIN000040963.

How Individual States and Traits Predict Aesthetic Appreciation of Haiku Poetry

Abstract: The factors influencing poetry’s aesthetic appreciation are largely unknown. Some studies have reported features that affect the aesthetic appreciation of poetry. This study sought to determine whi...

Fossil Fuel Fiction and the Geologies of Race

Abstract: Abstract This essay argues for an energy literary criticism that centers the problem of the energy epoch as the problem of the color line. It does so by reading a set of novels—Helena María Viramontes's Under the Feet of Jesus (1995) and Colson Whitehead's Zone One (2011) and The Underground Railroad (2016)—as fossil fuel fictions that illuminate the conjuncture of energy and racial capitalism. These works unearth the racialized world making of extractive energy regimes by articulating energy's social production of race across the colonial histories and geographies of the Anthropocene. The entanglement of racialized bodies and hydrocarbon matter across biological, historical, and geological time scales in these novels formalizes what Kathryn Yusoff calls the “geologies of race.” Excavating the racial infrastructures scaffolding the Anthropocene's power grids, Viramontes's and Whitehead's georacial imaginations envision decolonial and abolitionist energy futures for Brown and Black lives.

Top-heavy stellar mass distribution in galactic nuclei inferred from the universally high abundance ratio of [Fe/Mg]

Abstract: ABSTRACT Recent observations of active galactic nuclei (AGNs) have shown a high Fe ii/Mg ii line-flux ratio in their broad-line regions, nearly independent of redshift up to z ≳ 6. The high flux ratio requires rapid production of iron in galactic nuclei to reach an abundance ratio of [Fe/Mg] ≳ 0.2 as high as those observed in matured galaxies in the local universe. We propose a possible explanation of rapid iron enrichment in AGNs by massive star formation that follows a top-heavy initial mass function (IMF) with a power-law index of Γ larger than the canonical value of Γ = −2.35 for a Salpeter IMF. Taking into account metal production channels from different types of SNe, we find that the high value of [Fe/Mg] ≳ 0.2 requires the IMF to be characterized with Γ ≳ −1 (Γ ≳ 0) and a high-mass cutoff at Mmax ≃ 100–150 M⊙ (Mmax ≳ 250 M⊙). Given the conditions, core-collapse SNe with M* ≳ 70 M⊙ and pair-instability SNe give a major contribution for iron enrichment. Such top-heavy stellar IMFs would be a natural consequence from mass growth of stars formed in dense AGN discs under Bondi-like gas accretion that is regulated by feedback at M* ≳ 10 M⊙. The massive stellar population formed in AGN discs also leave stellar-mass black hole remnants, whose mergers associated with gravitational-wave emission account for at most 10 per cent of the merger rate inferred from LIGO/Virgo observations to simultaneously explain the high [Fe/Mg] ratio with metal ejection.

Hot Circumsingle Disks Drive Binary Black Hole Mergers in Active Galactic Nucleus Disks

Abstract: Abstract Binary black hole (BBH) mergers, particularly those with component masses in the pair-instability gap, may be produced by hierarchical mergers in the disks surrounding Active Galactic Nuclei (AGNs). While the interaction of an embedded BBH with an AGN disk is typically assumed to facilitate a merger, recent high-resolution hydrodynamical simulations challenge this assumption. However, these simulations often have simplified treatments for gas thermodynamics. In this work, we model the possible consequence of various feedback from an embedded BBH with a simple model that maintains an enhanced temperature profile around each binary component. We show that when the minidisks around each BH become hotter than the background by a factor of three, the BBH orbital evolution switches from expansion to contraction. By analyzing the gravitational torque profile, we find that this change in direction is driven by a weakening of the minidisk spirals and their positive torque on the binary. Our results highlight the important role of thermodynamics around BBHs and its effect on their orbital evolution, suggesting that AGN disks could be efficient factories for BBH mergers.