Predicting the humidity control capacity of material based on a linear excitation-response relationship

The Cb value is a useful parameter for estimating the humidity control capacity of materials. It is defined as the ratio of the range of variation of relative humidity in a steel box lined with the material of interest to that in an empty steel box, when sinusoidal temperature variation is applied. However, because it takes a long time to obtain the Cb values for materials at each temperature variation period, we developed an easier method based on a linear excitation-response theory to obtain the Cb values without measuring at each period. Japanese cedar was the material used in this study. The temperature excitation, a jump from a constant temperature to another constant temperature, was used to obtain the absolute humidity response. Under the assumption that the temperature excitation-humidity response relationship is linear, we were able to predict humidity variation to sinusoidal temperature variation at any period, and we obtained the Cb value for each temperature variation period. Predicted values agreed well with the experimental values. From this, it was found that the Cb value could be predicted without measuring the Cb value at each period over a long time. In addition, the peak time difference, which is closely related to the Cb value, could also be predicted in a similar manner.     

Spironolactone, but not Eplerenone, Impairs Glucose Tolerance in a Rat Model of Metabolic Syndrome

Although some clinical studies have suggested that spironolactone (SPL), a mineralocorticoid receptor (MR) antagonist, appears to increase the blood glucose levels, experimental studies have not supported this notion. Here, we investigated the effect of SPL on blood glucose levels in SHR/NDmcr-cp(cp/cp) (ND) rats, an animal model of metabolic syndrome, in comparison with that of eplerenone (EPL), another MR antagonist. At the same dose of 100 mg/kg, SPL and EPL increased the urinary sodium-to-potassium ratio to a comparable extent, indicating that both agents have similar renal MR antagonistic efficacy in ND rats. Interestingly, SPL but not EPL significantly increased the level of blood glucose. The oral glucose tolerance test revealed that treatment with SPL led to glucose intolerance. The levels of serum insulin and adiponectin, regulators of the blood glucose level, were virtually unaffected by treatment with SPL. On the other hand, SPL induced a marked increase in the blood level of aldosterone, known to be a risk factor for insulin resistance. These results demonstrate that in comparison with EPL, SPL characteristically impairs glucose tolerance in an animal model of metabolic syndrome, in association with a higher blood level of aldosterone.     

CONTRAST AGENT Gd‐EOB‐DTPA (EOB·Primovist®) FOR LOW‐FIELD MAGNETIC RESONANCE IMAGING OF CANINE FOCAL LIVER LESIONS

Contrast‐enhanced magnetic resonance (MR) imaging with a new liver‐specific contrast agent gadolinium‐ethoxybenzyl‐diethylenetriamine penta‐acetic acid (Gd‐EOB‐DTPA; EOB·Primovist®) was studied in 14 normal beagles and 9 dogs with focal liver lesions. Gd‐EOB‐DTPA accumulates in normally functioning hepatocytes 20 min after injection. As with Gd‐DTPA, it is also possible to perform a dynamic multiphasic examination of the liver with Gd‐EOB‐DTPA, including an arterial phase and a portal venous phase. First, a reliable protocol was developed and the appropriate timings for the dynamic study and the parenchymal phase in normal dogs using Gd‐EOB‐DTPA were determined. Second, the patterns of these images were evaluated in patient dogs with hepatic masses. The optimal time of arterial imaging was from 15 s after injection, and the optimal time for portal venous imaging was from 40 s after injection. Meanwhile, the optimal time to observe changes during the hepatobiliary phase was from 20 min after injection. In patient dogs, 11 lesions were diagnosed as malignant tumors; all were hypointense to the surrounding normal liver parenchyma during the hepatobiliary phase. Even with a low‐field MR imaging unit, the sequences afforded images adequate to visualize the liver parenchyma and to detect tumors within an appropriate scan time. Contrast‐enhanced MR imaging with Gd‐EOB‐DTPA provides good demarcation on low‐field MR imaging for diagnosing canine focal liver lesions.     

Genetic Relationships Between Cercospora kikuchii Populations from South America and Japan

ABSTRACT A collection 160 isolates of Cercospora kikuchii was made from South America and 245 from Japan. DNA fingerprint patterns were analyzed based on amplified fragment length polymorphism among the sample isolates, dividing the isolates into seven lineages (I to VII). Partial nucleotide sequence analyses of the beta-tubulin gene supported this division into seven lineages. Lineages I and III commonly existed in South America and Japan. In all, 136 of the 160 isolates from South America and 223 of the 245 isolates from Japan belonged to lineage I, indicating that lineage I was the major lineage in each area; 5 isolates from South America and 8 isolates from Japan belonged to lineage III. Lineages II (12 isolates) and IV (2 isolates) were specific to Japan and lineages V (3 isolates), VI (1 isolate), and VII (15 isolates) specifically existed in South America. These results suggest that the population genetic structure of C. kikuchii was different between South America and Japan, but the dominance of lineage I was common between the two areas.     

Mild drying of sandy soil can physically limit the uptake of phosphorus by rainfed lowland rice in northeast Thailand

ABSTRACT

Poor response of rice to phosphorus (P) fertilization and low phytoavailability of soil P have been reported in sandy rainfed fields in northeast Thailand. In order to evaluate the effects of mild soil drying on the uptake of P by rainfed lowland rice, we carried out nutrient omission trials for nitrogen (N) and P at Ubon Ratchathani Rice Research Center under rainfed and flooded conditions. The surface soil was classified as sandy loam. To avoid severe soil drying and drought stress in the rainfed field, soil water potential at a depth of 20 cm was maintained at the field capacity (> ?20 kPa) by flush irrigation. The effects of flooding and drying on the soil properties were also evaluated in the laboratory using soils with diverse textures in and around the center. In the field experiments, the above-ground biomass of rice plants (RD6) did not respond significantly to P fertilization in the rainfed field, although it responded positively to N fertilization. Root length in the surface 10 cm under the rainfed condition was significantly smaller than that under the flooded condition due partly to the increased soil hardness upon drying, but this could not quantitatively explain the large discrepancy of P uptake observed between the rainfed and flooded conditions. Under the rainfed condition, the P uptake did not increase significantly, even when the concentration of soil Bray P was tripled by transferring the surface soil from the flooded to the rainfed field. From the laboratory experiments, it was further suggested that soil P was supplied mainly by diffusion and that the effective diffusion coefficient for P can become less than one-tenth of the value in the flooded field when the sandy soil with clay at around 10% dried to ?100 kPa. Our results suggest that the uptake of P by the rainfed lowland rice grown in sandy soil can be limited physically by mild soil drying that reduces the supply of P to roots by diffusion rather than the chemical extractability of soil P.     

Soil management: The key factors for higher productivity in the fields utilizing the system of rice intensification (SRI) in the central highland of Madagascar

The system of rice intensification (SRI) developed in Madagascar in the 1980s has been promoted as an integrated crop and resource management approach to rice-cultivation, especially for resource-limited smallholder farms. While advocates have claimed that SRI could boost rice yields with less external input, many criticisms have challenged its effectiveness regarding yields and applicability to larger-scale rice farming systems. In this study, we conducted a field survey and on-farm experiments to assess rice yield performance and key management practices on a few of the early SRI-practicing smallholder farms in the central highland of Madagascar.Rice grain yields at the survey fields were 9.9 t ha⁻¹ maximum without using mineral fertilizer. Deep plowing to the depth of 25–30 cm as well as SRI practices have been conducted continuously since the early 1990s. In addition, an effective drainage system facilitated intensive water management at these high-yielding fields. On-farm experiments demonstrated some yield increases with no interaction for the examined SRI practices, though the effects were not great enough to explain the high yields at these fields. The soils of these high-yielding fields contained relatively large amounts of soil organic carbon (SOC) from the surface to the deep soil layers, and the soil mineralizable nitrogen was closely correlated with rice grain yields.The results indicated that the high yields at the fields of those who were early to adopt SRI were mainly due to the soil fertility associated with great nitrogen-supplying ability, rather than ‘synergetic effects’ of the SRI components. This high N-supplying ability of the soil and accumulated SOC from surface to deep soil layers were attributable to the long-term combined practices of extensive organic applications and deep plowing. Soil hydrology could be another key factor stimulating high rates of soil N-mineralization.These management practices were, however, only applied to the limited numbers of fields within less than 1.0 ha of total landholdings of these farmers due to the great demand in labor and organic resources and the difficulty in controlling irrigation water. Intensive weeding and widely spaced transplanting of young seedlings were also performed in the fields with irrigation and drainage systems sufficient to avoid yield losses from flooding and drought. Although extensive and long-term systematic research is further required to fully assess the benefits of this sort of intensive management as opposed to conventional methods, the preferential allocation of intensive management by the successful SRI-adopters might be the implication of its location-specificity and difficulty in scaling up even within the resource-limited smallholder farms.     

Transgenic apple (Malus x domestica) shoot showing low browning potential

Transgenic apple shoots were prepared from leaf disks by using Agrobacterium tumefaciens carrying the kanamycin (KM) resistance gene and antisense polyphenol oxidase (PPO) DNA. Four transgenic apple lines that grew on the medium containing 50 microgram/mL KM were obtained. They contained the KM resistance gene and grew stably on the medium for >3 years. Two transgenic shoot lines containing antisense PPO DNA in which PPO activity was repressed showed a lower browning potential than a control shoot.     

Detection of changes in taste of japonica and indica brown and milled rice (Oryza sativa L.) during storage using physicochemical analyses and a taste sensing system

Changes in the taste of japonica, hybrid, and indica brown and milled rice, stored for 10 months at low (5 degrees C, 65-70% relative humidity) and room temperatures were observed by physicochemical analyses and a novel method using a taste sensing system. During storage, some properties increased or decreased while others were fairly constant. The main taste components of cooked rice such as sweetness (sucrose) and umami tastes (glutamic acid and aspartic acid) were reduced during storage, whereas glucose and fructose increased. The increase of fat acidity and consequent decrease of the pH value of the cooking solution may contribute to the off-taste of cooked stored rice. A taste sensing system with 10 lipid membrane sensors was also used to classify new and old rice samples using principal component analysis. Fresh and room temperature stored japonica and indica rice could be clearly distinguished; however, it was not possible to differentiate the samples stored at low temperature.     

Effect of roasting on properties of the zinc-chelating substance in coffee brews

ApV is a brownish polymer with zinc-chelating activity in brewed coffee. We investigated in this study the effects of roasting on the zinc-chelating, reducing, and antioxidative activities of ApV from light-, medium-, and dark-roasted coffee. We also discuss the effect on the zinc-chelating activity of adding milk to the brewed coffee. The chelating activities of ApVs were evaluated by the tetramethyl murexide method. As the intensity of roasting increased, the yield of ApV increased, and the brown color and molecular weight of ApV respectively became darker and higher. Increasing the degree of roasting also decreased the zinc-chelating activity of ApV. The reducing activities of ApVs estimated by the indophenol method were stronger than those of ascorbic acid. Both the antioxidative activity estimated by the ABTS assay and the reducing activity of ApV increased with roasting. When milk was added to instant coffee and its ApV was prepared, the zinc-chelating activity of ApV was not changed.