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Intervertebral disc (IVD) degeneration (IDD), a highly prevalent pathological condition worldwide, is widely associated with back pain. Treatments available compensate for the impaired function of the degenerated IVD but typically have incomplete resolutions because of their adverse complications. Therefore, fundamental regenerative treatments need exploration. Mesenchymal stem cell (MSC) therapy has been recognized as a mainstream research objective by the World Health Organization and was consequently studied by various research groups. Implanted MSCs exert anti-inflammatory, anti-apoptotic, and anti-pyroptotic effects and promote extracellular component production, as well as differentiation into IVD cells themselves. Hence, the ultimate goal of MSC therapy is to recover IVD cells and consequently regenerate the extracellular matrix of degenerated IVDs. Notably, in addition to MSC implantation, healthy nucleus pulposus (NP) cells (NPCs) have been implanted to regenerate NP, which is currently undergoing clinical trials. NPC-derived exosomes have been investigated for their ability to differentiate MSCs from NPC-like phenotypes. A stable and economical source of IVD cells may include allogeneic MSCs from the cell bank for differentiation into IVD cells. Therefore, multiple alternative therapeutic options should be considered if a refined protocol for the differentiation of MSCs into IVD cells is established. In this study, we comprehensively reviewed the molecules, scaffolds, and environmental factors that facilitate the differentiation of MSCs into IVD cells for regenerative therapies for IDD.

Improvements in envelope performance have reduced heat loss from insulation, and the ratio of heat loss through ventilation load has become relatively large. In recent years, the use of heat recovery ventilation systems (HRV) has particularly increased. However, ventilation generates not only ventilation load but also air conveying fan power, such that conserving energy for both is important. Therefore, this paper focuses on a passive ventilation system with a solar air heater (PVSAH), which is a passive ventilation system that does not use air conveying fan power and uses a solar air heater that uses solar energy. The total energy consumption of the PVSAH, the widely used mechanical exhaust ventilation system (EV), and the HRV, which has high energy efficiency, was compared with the ventilation load plus air conveying fan power. The primary energy evaluation and carbon dioxide (CO2) emissions were compared by region, and the optimal system was proposed according to regional characteristics. In warmer zones, the PVSAH saved the most energy, while the HRV increased energy consumption. The comparison of CO2 emissions by ventilation systems when using heat pumps for cooling and heating showed that PVSAH > MEV > HRV for Heating Degree-Day (HDD) 1500 and below, PVSAH > HRV > MEV for HDD 1500 to 2750, and HRV > PVSAH > MEV for HDD 2750 and above. MEV were favored in that order. As the CO2 emission factor decreases, the difference in CO2 emissions between systems decreases. If the difference in emissions becomes smaller, then considering the initial and running costs and the risk of failure of the system is crucial. A simple system configuration with low risks of failure and maintenance, such as PVSAH, may prove advantageous in the future.

We have clarified that external insulation reduces the probability of reinforcement corrosion in reinforced concrete buildings in cold snowy districts by 45–78%. Renovation of external insulation is one of the effective methods for improving the insulation performance and durability of reinforced concrete buildings, but there are almost no data that demonstrate durability. Therefore, the carbonation depth and the cover depth were investigated for six medium-rise-wall type reinforced concrete buildings in Hokkaido, Japan, which had been refurbished for external insulation. As a result, it was clarified that the external insulation suppressed the carbonation depth by 30% or more, even when the bonding method of the external insulation was different. In addition, it was clarified that the external insulation further suppressed carbonation in walls where the carbonation depth tended to increase in snowy cold districts. Specifically, external insulation reduced carbonation by up to 35% on surfaces that tend to dry out due to sunlight, and by 49% on surfaces that are affected by water that deteriorates the concrete surface layer.

Since the Japanese Building Standards Act was revised in 2000, the installation of steel timber connectors (STCs) to reinforce timber frame (TF) connections has been mandated for new-build TF houses in Japan. However, for the TF houses built before then, more than 40% do not have sufficient STCs and are considered earthquake-prone. This study proposed a simple and easy seismic retrofit technique for such earthquake-prone existing houses. The proposed technique can reinforce TF connections using only plywood and common nails and achieve equivalent performance to the benchmark STCs used in Japanese TF houses, such as the “CP-T type” or the combination of “VP type” and “BP type” STCs. Experiments were performed to compare the proposed technique with the STCs using pullout and full-scale in-plane cyclic tests. The experimental results showed that the proposed technique had a higher seismic performance than the STCs, which was particularly excellent in displacement ductility to prevent a collapse of the TF house without damaging the timbers. The proposed technique will be accepted by many carpenters when retrofitting earthquake-prone existing houses because simple and easy.

Rice varietal differences were compared between japonica type (JAT) and indica type (INT) and between panicle number type (PNT) and panicle weight type (PWT) in terms of tiller and panicle development. Rice varieties PNT-JAT Hinohikari, PWT-JAT Akenohoshi, PNT-INT IR36, and PWT-INT Takanari were used in the field experiments. Tiller bud formation and tiller leaf emergence occurred slightly later in the PWT than in the PNT varieties. These parameters occurred slightly earlier in the INT than in the JAT varieties. The maximum number of tillers was greater in IR36 than in Takanari, Hinohikari, and Akenohoshi. The number of panicles per unit area (PN) was greater in IR36 and Hinohikari than in Akenohoshi and Takanari. The widths of the shoot apical meristem (SAM) just before panicle initiation were in the order of Akenohoshi > Hinohikari = Takanari > IR36. The number of spikelets per panicle (SN) was in the order of Takanari = Akenohoshi > IR36 > Hinohikari. In conclusion, the PWT varieties, which had relatively wider SAM, presented with the promotion of main shoot development and the suppression of tiller development. Consequently, PN decreased and SN increased in PWT varieties. INT varieties presented with the promotion of tiller and rachis branch development, which resulted in increases in both PN and SN. These developmental factors may determine varietal differences in the total number of spikelets per unit area. Abbreviations CGR: crop growth rate; DEL: differences between the numbers of emerged leaves in the tiller and those in the main shoot; DIL: differences between the number of initiated leaves in the tiller and those in the main shoot; INT: indica type; JAT: japonica type; MLAI: mean leaf area index; NAR: net assimilation rate; PN: the number of panicles per unit area; SN: the number of spikelets per panicle; PNT: panicle number type; PWT: panicle weight type; SAM: shoot apical meristem; TSN: the total number of spikelets per unit area

In this paper, the authors examined the technology to maximize the use of renewable energy. Passive ventilation systems are expected to reduce the energy consumption of the fan and the maintenance burden. In addition, the wall-mounted solar air heater can supply thermal energy without using any energy at all. Therefore, this paper presents a “passive ventilation system with a solar air heater” that combines a passive ventilation system with the solar air heater to preheat the air. This system can reduce the ventilation load. To evaluate the solar air heater performance in a real environment, we developed a simulation for calculating the heat collection capacity of the solar air heater, and then the system was implemented in a real building for verification. The simulation performs hourly unsteady calculations, allowing for accurate evaluation of the annual simulation. Based on the measurement results, the effects of heating load reduction and prediction methods are presented. The solar air heater reduced the monthly ventilation load by up to 50% or more, and by at least 15%. It was also confirmed that there was a high correlation between the actual measurements and the simulation results.

The genes TAWAWA1 (TAW1) and ABERRANT PANICLE ORGANIZATION1 (APO1) increase the number of spikelets per panicle (SN). In the present study, we examined the effects of these genes on morphological traits, yield, and yield-related traits including yield components using the near-isogenic lines (NILs) in the genetic background of a japonica rice variety, Koshihikari – NIL-taw1, NIL-apo1-D3, and NIL-apo1-D4 – in a field experiment. The SN and total number of spikelets per area of the three NILs were larger than those of Koshihikari. However, the yield of the three NILs did not exceed that of Koshihikari due to their low filling ability. Interestingly, our field experiments indicated that TAW1 did not affect the diameter of internodes and the PN, whereas APO1 decreased the PN and increased the diameter of internodes. These results suggest that TAW1 and APO1 differently affect yield-related traits.

This study was conducted to clarify the relationship between the number of pollen grains per anther and spikelet fertility under low temperature conditions in the rice cultivars and lines including lines with quantitative trait loci (QTL) for cold tolerance, adapted to the Tohoku region of northern Japan. Cold-water treatment decreased anther length, the number of pollen grains per anther, and spikelet fertility in all cultivars and lines. The number of pollen grains was proportional to anther length in all cultivars and lines and under all temperatures. Spikelet fertility decreased with decreasing the number of pollen grains in cold-water treatments at 18.5 and 19.3 °C. ‘Ouu 415’, with the qLTB3 QTL for cold tolerance, had 28% more pollen grains and 9% higher spikelet fertility than the recurrent parent, ‘Hitomebore’, in the 18.5 °C cold-water treatment, suggesting that qLTB3 increased both parameters. Lines with the qCTB8 QTL for cold tolerance had significantly more pollen grains in two of the three years and significantly higher spikelet fertility in all three years in the 19.3 °C cold-water treatment, suggesting that qCTB8 reinforced cold tolerance. Ctb1, a proposed cold-tolerance QTL, had no effect on the number of pollen grains or spikelet fertility. In conclusion, the cultivars and lines with more pollen grains had a higher cold tolerance. Some of QTLs were inferred to increase the number of pollen grains and reinforce cold tolerance.

Quantitative trait loci (QTL) affecting the germination rate, coleoptile length, and shoot dry weight were analyzed under submerged and low temperature conditions using inbred lines derived from crossing the rice cultivars Ouu 365 and Arroz da Terra. The QTLs that increased the germination rate and shoot dry weight by Arroz da Terra allele were detected on the same region of chromosome 3, where the low temperature germinability gene, qLTG3-1, localized, suggesting that greater germinability might lead to increased shoot growth in paddy fields. The QTLs that increased the coleoptile length by Ouu 365 and Arroz da Terra alleles were detected on chromosome 8 and 11, respectively. The analysis of the known germinability genes suggested that functional allele of qLTG3-1 increased germination rates of the inbred lines. However, Rc which induced red pigmentation in pericarp declined the germination rates of the lines with functional qLTG3-1.

Excess ferrous iron in lowland soil is known to inhibit the growth of rice. A quantitative trait locus (QTL) analysis for susceptibility to ferrous iron was performed using chromosomal segments substitution lines (CSSLs). Kasalath, an indica rice cultivar, is known to be susceptible to ferrous iron and accumulate excess iron in shoots. The shoot iron concentration was examined in 39 CSSLs carrying Kasalath chromosomal segments in a background of Koshihikari, a japonica cultivar. Kasalath grown in a hydroponic culture solution containing excess ferrous iron, had a higher shoot iron concentration than Koshihikari. Of the CSSLs, SL208, which carries the Kasalath chromosomal segment on chromosome 3, had a significantly higher shoot iron concentration than Koshihikari, and none of the CSSLs had a shoot iron concentration significantly lower than Koshihikari. This finding suggests that the putative QTL affecting the shoot iron concentration is between the markers R663 and S1571 on chromosome 3.

A two-year field experiment was conducted with japonica type high-yielding variety “Fukuhibiki,” indica type high-yielding variety “Takanari,” large grain type high-yielding variety “Bekoaoba” and conventional japonica type varieties “Akitakomachi” and “Hitomebore” in the Tohoku region (colder area of Japan). The panicles of Takanari and Bekoaoba located lower in the canopy, and the flag leaf of those varieties intercept more solar radiation, because the flag leaf was long and the first internode of panicle did not emerge above the lamina joint of the flag leaf in Takanari and the panicle hung lower in Bekoaoba. The three high-yielding varieties produced a large sink size, due to the large potential sink size in Takanari, the very large grain size in Bekoaoba and the rather large number of spikelets per panicle and somewhat large grain size in Fukuhibiki. Based on dry matter production, the three high-yielding varieties had a high harvest index, although there were little varietal differences in top dry weight at maturity. Unhulled rice weight of the three high-yielding varieties was heavier than that of other varieties at 30 days after heading (30 DAH). However, there were no varietal differences in the increase in unhulled rice weight from 30 DAH to maturity (later than 50 DAH), probably due to the continual growth of the grains located lower until the late ripening period in all varieties. In conclusion, the traits related to high yield varied greatly among varieties. However, the three high-yielding varieties had a large sink size, heavy unhulled rice weight at 30 DAH and high harvest index.

To achieve super high yield of more than 10 t ha-1 in the Tohoku region (colder area of Japan), we conducted a two-year field experiment using a large grain type high-yielding rice variety Bekoaoba. Although high nitrogen application (HN) increased the top dry weight at the full heading stage only slightly, it increased the sink size (single grain weight x the number of spikelets per area), leaf area index and nitrogen content at the full heading stage and accordingly the dry matter production during the ripening period. As a result, the gross hulled rice yield was higher under HN than under standard nitrogen application (SN). Under HN, early topdressing increased not only the number of differentiated spikelets but also the number of degenerated spikelets. As a result, the sink size and gross hulled rice yield of the plants were not changed by the early topdressing. Under HN, the higher planting density increased the number of panicles per area but decreased the number of spikelets per panicle. As a result, the sink size and gross hulled rice yield were not changed with the planting density. In conclusion, HN produced the gross hulled rice yield of more than 9 t ha-1. However, the gross hulled rice yield could not be increased more than 10 t ha-1 by regulation of the timing of topdressing and /or the planting density. We discussed the strategies for super high-yielding rice in the Tohoku region.

The yielding ability of a new rice cultivar Akisayaka was compared with that of a standard rice cultivar Yumehikari. The refined grain yield was 9% larger in Akisayaka than in Yumehikari since Akisayaka had more panicles and spikelets per unit area but had a similar percentage of ripened grain. Although the leaf area index (LAI) in Akisayaka was similar to that in Yumehikari, the leaf area of the flag leaf per unit area of Akisayaka was smaller than that of Yumehikari at the full heading stage. This indicates that Akisayaka had a larger number of smaller upper leaves than Yumehikari. The refined grain weight of Akisayaka was similar to that of Yumehikari at 30 days after heading. This implies that the plant type of Akisayaka is not so important for increasing dry matter production from early to middle ripening period although small upper leaves seems to suppress overluxuriant growth. Accordingly the most important factor for the high yield of Akisayaka was considered to exist in the late ripening stage. The refined grain weight of Akisayaka increased more rapidly than that of Yumehikari from 30 to 45 days after heading. In addition, the leaf chlorophyll content estimated with chlorophyll meter (SPAD) and top dry weight of Akisayaka exceeded those of Yumehikari at the late ripening stage. These results suggest that the large number of spikelets per unit area and the continuation of sink and source ability during the late ripening stage caused the high yielding ability of Akisayaka.

The phenological development of winter wheat Iwainodaichi seeded early was compared with that of spring wheat Chikugoizumi based on the temperature. In this paper, the developmental phase from the sowing to double ridge is referred to phase 1, that from double ridge to anthesis phase 2 and that from the anthesis to maturity phase 3. The duration of phase 1 in Iwainodaichi was almost constant independent of the mean temperature in this phase, but that in Chikugoizumi decreased as the mean temperature in this phase increased. When seeded early, the duration of phase 1 was obviously longer in Iwainodaichi than in Chikugoizumi since the mean temperature in this phase was higher when seeded early. The duration of phase 2 decreased in both varieties as the mean temperature and photoperiod in this phase increased. When seeded early, phase 2 was shorter in Iwainodaichi than in Chikugoizumi, since the mean temperature was higher and photoperiod longer in this phase in Iwainodaichi than in Chikugoizumi. The duration of phase 3 decreased as the mean temperature in this phase increased in both varieties and was shorter in Iwainodaichi than in Chikugoizumi at the same mean temperature. Consequently, Iwainodaichi reached the double ridge stage later but reached maturity at about the same time as Chikugoizumi when seeded early.