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result(s) for
"Saito, Kazuyuki"
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Winter 2009-2010: A case study of an extreme Arctic Oscillation event
by
Barlow, Mathew
,
Foster, James
,
Saito, Kazuyuki
in
Arctic Oscillation
,
Atmospheric sciences
,
climate dynamics
2010
Winter 2009–2010 made headlines for extreme cold and snow in most of the major population centers of the industrialized countries of the Northern Hemisphere (NH). The major teleconnection patterns of the Northern Hemisphere, El Niño/Southern Oscillation (ENSO) and the Arctic Oscillation (AO) were of moderate to strong amplitude, making both potentially key players during the winter of 2009–2010. The dominant NH winter circulation pattern can be shown to have originated with a two‐way stratosphere‐troposphere interaction forced by Eurasian land surface and lower tropospheric atmospheric conditions during autumn. This cycle occurred twice in relatively quick succession contributing to the record low values of the AO observed. Using a skillful winter temperature forecast, it is shown that the AO explained a greater variance of the observed temperature pattern across the extratropical landmasses of the NH than did ENSO.
Journal Article
Simplified detection of the species of origin of antler velvets using single-stranded tag hybridization chromatographic printed-array strip
2023
In this study, we developed a convenient and easy-to-use origin identification method for antler velvets based on a simple DNA extraction technique and single-stranded tag hybridization chromatographic printed-array strip (STH-PAS). The primer sets used to detect
Cervus elaphus
,
Rangifer tarandus
, and 12S rRNA did not engage in non-specific reactions such as primer dimer formation. In both the triplex and singleplex assays, the sensitivity was < 1 ng DNA. Moreover,
Cervus elaphus
DNA could be detected in OTC crude drug products. Although the detection sensitivity resulting from the simplified extraction was slightly lower than that obtained with extraction by conventional methods, the amount of DNA was sufficient even from a small sample. The choice of a triplex or singleplex assay will depend on the purpose of the test. For example, if it is important to determine whether the antler velvet is derived from
Cervus elaphus
or
Rangifer tarandus
, a triplex assay is appropriate. If it is necessary to explore whether antler velvet from
Cervus elaphus
is included in an OTC crude drug product, a singleplex assay using the
Cervus elaphus
primer set is informative. If it is necessary to explore whether powdered antler velvet includes counterfeit products (from
Rangifer tarandus
), a singleplex assay employing the
Rangifer tarandus
primer is appropriate. The singleplex assay detects minor components even at a 1,000:1 ratio. Our study thus demonstrated the utility of a method combining simple DNA extraction with STH-PAS for efficient identification of the origin of antler velvets.
Journal Article
Projections of surface air temperature required to sustain permafrost and importance of adaptation to climate change in the Daisetsu Mountains, Japan
2021
Permafrost is known to occur in high mountainous areas such as the Daisetsu Mountains in Japan, which are located at the southernmost limit of the permafrost distribution in the world. In this study, areas with climatic conditions suitable for sustaining permafrost in the Daisetsu Mountains are projected using bias-corrected and downscaled climate model outputs and statistical relationships between surface air temperatures and permafrost areas. Using freezing and thawing indices, the size of the area in the Daisetsu Mountains where climatic conditions were suitable for permafrost were estimated to be approximately 150 km
2
in 2010. Under the RCP8.5 scenario, this area is projected to decrease to about 30 km
2
by 2050 and it is projected to disappear by around 2070. Under the RCP2.6 scenario, the area is projected to decrease to approximately 20 km
2
by 2100. The degradation of mountain permafrost could potentially affect the stability of trekking trails due to slope displacement, and it may also have deleterious effects on current alpine ecosystems. It is therefore important to accurately monitor changes in the mountain ecosystem environment and to implement measures to adapt to an environment that is projected to change significantly in the future.
Journal Article
Estimating individual mtDNA haplotypes in mixed DNA samples by combining MinION and MiSeq
by
Nakanishi Hiroaki
,
Hara Masaaki
,
Saito Kazuyuki
in
Deoxyribonucleic acid
,
Forensic medicine
,
Genomics
2022
We tried to estimate individual mtDNA haplotypes in mixed DNA samples by combining MinION and MiSeq. The BAM files produced by MiSeq were viewed using Integrative Genomics Viewer (IGV) to verify mixed bases. By sorting the reads according to base type for each mixed base, partial haplotypes were determined. Then, the BAM files produced by MinKNOW were viewed using IGV. To determine haplotypes with IGV, only mixed bases determined by MiSeq were used as target bases. By sorting the reads according to base type for each target base, each contributor’s haplotype was estimated. In mixed samples from two contributors, even a haplotype with a minor contribution of 5% could be distinguished from the haplotype of the major contributor. In mixed samples of three contributors (mixture ratios of 1:1:1 and 4:2:1), each haplotype could also be distinguished. Sequences of C-stretches were determined very inaccurately in the MinION analysis. Although the analysis method was simple, each haplotype was correctly detected in all mixed samples with two or three contributors in various mixture ratios by combining MinION and MiSeq. This should be useful for identifying contributors to mixed samples.
Journal Article
Unique pattern of dietary adaptation in the dentition of Carnivora: its advantage and developmental origin
2016
Carnivora is a successful taxon in terms of dietary diversity. We investigated the dietary adaptations of carnivoran dentition and the developmental background of their dental diversity, which may have contributed to the success of the lineage. A developmental model was tested and extended to explain the unique variability and exceptional phenotypes observed in carnivoran dentition. Carnivorous mammalian orders exhibited two distinct patterns of dietary adaptation in molars and only Carnivora evolved novel variability, exhibiting a high correlation between relative molar size and the shape of the first molar. Studies of Bmp7-hetero-deficient mice, which may exhibit lower Bmp7 expression, suggested that Bmp7 has pleiotropic effects on these two dental traits. Its effects are consistent with the pattern of dietary adaptation observed in Carnivora, but not that observed in other carnivorous mammals. A molecular evolutionary analysis revealed that Bmp7 sequence evolved by natural selection during ursid evolution, suggesting that it plays an evolutionary role in the variation of carnivoran dentition. Using mouse experiments and a molecular evolutionary analysis, we extrapolated the causal mechanism of the hitherto enigmatic ursid dentition (larger M2 than M1 and M3). Our results demonstrate how carnivorans acquired novel dental variability that benefits their dietary divergence.
Journal Article
Estimating included animal species in mixed crude drugs derived from animals using massively parallel sequencing
by
Saito, Kazuyuki
,
Hara, Masaaki
,
Yoneyama, Katsumi
in
631/1647/514/2254
,
631/208/514/2256
,
631/601
2021
We developed a method that can detect each animal species of origin for crude drugs derived from multiple animal species based on massively parallel sequencing analysis of mitochondrial genes. The crude drugs derived from animals investigated in this study were Cervi Parvum Cornu and Trogopterorum feces, which are derived from a mix of different animal species, two chopped cicada sloughs, and two commercial Kampo drugs. The mitochondrial 12S rRNA, 16S rRNA, and cytochrome oxidase subunit I gene regions were amplified and sequenced using MiSeq. The ratios of haplotype to total number of sequences reads were calculated after sequence extraction and trimming. Haplotypes that exceeded the threshold were defined as positive haplotypes, which were compared with all available sequences using BLAST. In the Cervi Parvum Cornu and Trogopterorum feces samples, the haplotype ratios corresponded roughly to the mixture ratios, although there was a slight difference from mixture ratios depending on the gene examined. This method could also roughly estimate the compositions of chopped cicada sloughs and Kampo drugs. This analysis, whereby the sequences of several genes are elucidated, is better for identifying the included animal species. This method should be useful for quality control of crude drugs and Kampo drugs.
Journal Article
Interannual Variations in Spring Snowmelt Timing of Alaskan Black Spruce Forests Using a Bulk‐Surface Energy Balance Approach
by
Ikawa, Hiroki
,
Nakai, Taro
,
Iwata, Hiroki
in
Air temperature
,
Alaskan boreal forest
,
Annual variations
2024
Spring snowmelt occurs for a short duration on an annual time scale, but their timings considerably affect the carbon and hydrological cycle in high‐latitude ecosystems. Here, we developed a simple snowmelt model, treating the ecosystem surface as a bulk‐surface layer. Energy fluxes across this bulk surface and the snow‐soil boundary determine snow temperature and the energy utilized for snowmelt. Parameterizing the bulk surface using decade‐long eddy covariance site data from two Alaskan open black spruce forests offered an opportunity to quantitatively evaluate meteorological drivers affecting snowmelt timings without the needs for detailed canopy information. The sensitivity analysis suggested that the total snowfall on the forest floor, ranging from 0.35 m in 2016 to about 1 m in 2018 and 2020, was the most crucial driver for snowmelt timing. This factor accounted for a 10‐day difference in the interannual variations in snow disappearance dates. The importance of the snowfall varied from year to year, and in 2013, the late snowmelt was characterized by low air temperatures, which increased sensible heat loss from the snowpack. The importance of atmospheric radiation was revealed in relatively warm years, such as 2016 and 2019. Our modeling approach necessitates adjusting one empirical parameter that reflects the heat conductivity from the bulk surface to the snow, based on observations. Nevertheless, despite this need for adjustment, the bulk‐surface approach helps identify important meteorological drivers underlying observed snowmelt within a simple theoretical framework. Plain Language Summary It is essential to understand why and how spring snowmelt occurs in boreal forests because of its impact on both the biological and hydrological processes in the ecosystem. However, meteorological drivers related to snowmelt often change simultaneously, which makes it challenging to determine which single driver is vital for snowmelt. To address this challenge, we constructed a simple snowmelt model that treats the ecosystem surface as a single bulk layer. The simple model bypasses the needs for detailed canopy information and is easily constrained by observed data. Applying the model to decadal observation data from Alaskan boreal forests, we found that snowfall, air temperature, and atmospheric radiation were important meteorological drivers for explaining interannual variations in snowmelt timing. Each of them explained about 1–2 weeks of snowmelt disappearance dates. We also demonstrated that the model helped explain why the snowmelt was late in 2013 and early in 2016 and 2019 and why snow disappearance dates differed between study sites. While a simple model has its limitations, it can be beneficial for understanding snowmelt characteristics within a simple theoretical framework. Key Points A model‐based approach was introduced to delineate the roles of meteorological drivers on interannual variations in snowmelt timing Snowfall was the most important driver of the interannual variation in snowmelt timing followed by air temperature and atmospheric radiation Late snowmelt in 2013 was attributed to low air temperature, increasing sensible heat loss from the snowpack
Journal Article
Long-term outcomes and safety of radical transmediastinal esophagectomy with preoperative docetaxel, cisplatin, and 5-fluorouracil combination chemotherapy for locally advanced squamous cell carcinoma of the thoracic esophagus
by
Hirano, Kosuke
,
Oya, Masatoshi
,
Saito, Kazuyuki
in
5-Fluorouracil
,
Antineoplastic Combined Chemotherapy Protocols - therapeutic use
,
Cancer therapies
2020
Background
It is unknown whether transmediastinal esophagectomy (TME) is an acceptable surgical procedure for locally advanced esophageal squamous cell carcinoma (ESCC). Therefore, we investigated the feasibility of long-term survival after TME with neoadjuvant docetaxel, cisplatin, and 5-fluorouracil combination chemotherapy (DCF therapy).
Methods
This retrospective, observational study included locally advanced resectable ESCC. All patients received two cycles of preoperative DCF therapy (60 mg/m
2
of docetaxel and cisplatin on day 1 and 700 mg/m
2
/day of 5-FU on days 1–5 in each cycle) followed by radical TME. The main outcomes were survival and the rate of adverse events of chemotherapy and surgery.
Results
Sixteen patients were included in this study. All patients received two cycles of DCF therapy, followed by surgery. The median follow-up duration of the 16 patients was 35.4 months. The 2-year overall survival (OS) was 93.3% (95% confidence interval [CI], 61.3–99.0), and the 3-year OS was 78.8% (95% CI, 47.3–92.7). The 2-year and 3-year relapse-free survivals were both 73.3% (95% CI, 43.6–89.1). Leukopenia and neutropenia occurred in most patients; however, they were controllable. Fifteen patients completed TME, and one was converted to open transthoracic esophagectomy because of tracheal injury. Three-field dissection was performed for 12 of 16 patients (75%), and R0 resection was achieved in 15 of 16 patients (93.8%). Three cases of grade IIIb chylothorax were observed. There was no mortality in this study.
Conclusion
Combined neoadjuvant DCF and TME for locally advanced ESCC was safe and less invasive than traditional therapies and had a satisfactory long-term prognosis.
Journal Article
Tundra fire alters vegetation patterns more than the resultant thermokarst
by
Go Iwahana
,
Saito, Kazuyuki
,
Tsuyuzaki, Shiro
in
Biodiversity
,
Climate change
,
Cluster analysis
2018
Tundra fires are increasing in their frequencies and intensities due to global warming, which alter revegetation patterns through various pathways. To understand the effects of tundra fire and the resultant thermokarst on revegetation, vegetation and related environmental factors were compared between burned and unburned areas of Seward Peninsula, Alaska, using a total of 140 plots, 50 cm × 50 cm each. The area was burned in 2002 and surveyed in 2013. Seven vegetation types were classified by a cluster analysis and were categorized along a fire-severity gradient from none to severe fire intensity. The species richness and diversity were higher in intermediately disturbed plots. Severe fire allowed the immigration of fire-favored species (e.g., Epilobium angustifolium, Ceratodon purpureus) and decreased or did not change the species diversity, indicating that species replacement occurred within the severely burned site. Although thermokarsts (ground subsidence) broadly occurred on burned sites, due to thawing, the subsidence weakly influenced vegetation patterns. These results suggest that the fire directly altered the species composition at a landscape scale between the burned and unburned sites and it indirectly altered the plant cover and diversity through the differential modification, such as thermokarst, at a small scale within the burned site.
Journal Article