This study focused on the antifungal and fungicidal effects of potassium 2-butyloctanoate (isoC12K), a branched fatty acid salt, against Malassezia furfur. Antifungal susceptibility tests showed that isoC12K exhibited high antifungal activity, with minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at a low concentration of 0.156 wt/v%. Furthermore, the FDA–PI double fluorescence staining method suggested that isoC12K may act fungicidally by impairing the cell membrane function of M. furfur. Furthermore, when isoC12K was used in combination with a commercially available shampoo, it was found that the addition of isoC12K conferred antifungal activity to the products that did not exhibit antifungal activity when used alone. In addition, a model shampoo containing isoC12K as a cleansing ingredient was prepared, and its cleansing effect and effect on hair were evaluated. The results showed that it had the same cleansing ability as a shampoo containing the conventional surfactant SDS, while tending to cause less damage to the hair surface and internal proteins. These results demonstrate that isoC12K possesses high antifungal activity against M. furfur while also combining functionality as a cleansing agent with low damage to hair.

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This study proposes a novel evaluation method for deodorization performance based on adsorption isotherm and material balance. Traditional methods for deodorization performance relied on concentration reduction rates, making it difficult to predict deodorization performance when space volume or deodorant quantity changed. The proposed method determines the equilibrium concentration and equilibrium amount adsorbed by finding the intersection of a material balance equation and the deodorant's specific adsorption isotherm.

Key advantages of this approach include predicting performance at varying initial concentrations, calculating the necessary amount of deodorant to reach olfactometry threshold concentration, and scaling up results from small-scale bag tests to actual room sizes.

Validation experiments used by ammonia and an activated carbon filter as an odor and a deodorant, respectively demonstrated that the ammonia adsorption to activated carbon filter followed the Freundlich adsorption isotherm. The author successfully predicted the required sample weight to achieve an ammonia threshold concentration of 1.5 ppm, even when the gas volume was increased threefold. This methodology allows for the prediction of deodorization performance under various conditions.

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This study aimed to identify the temperature range at which heat stress occurs for sows in farrowing piggeries, from the perspective of barn environmental management using segmented regression analysis. The physiological responses of rectal temperature, skin temperature, and respiration rate used as dependent variables, while the independent variables were ambient temperature, the temperature–humidity index (THI), and the wet-bulb globe temperature (WBGT) were used as independent variables. The breakpoints obtained from the segmented regression analysis were 29.1 °C for ambient temperature, 79.6 for THI, and 25.4 °C for WBGT when rectal temperature was used; 17.1 °C, 61.4, and 12.4 °C, respectively, when skin temperature was used; and 22.3 °C, 70.9, and 22.1 °C, respectively, when respiration rate was used. When the respiration rate breakpoint was defined as the heat stress caution zone and the rectal temperature breakpoint as the heat stress danger zone, the caution zone for heat stress in sows in farrowing piggery was estimated to occur at ambient temperatures ≥22.3 °C, THI ≥70.9, and WBGT ≥22.1 °C, whereas the danger zone was estimated to occur at ambient temperatures ≥29.1 °C, THI ≥79.6, and WBGT ≥25.4 °C. Furthermore, WBGT, which integrates ambient temperature, relative humidity, and radiant heat, is an effective index for evaluating heat stress and guiding environmental improvements in farrowing piggery.

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This study investigates the indoor environmental characteristics and particle removal performance for allergen mitigation when a residential air conditioner (AC) and an air purifier (AP) are operated simultaneously. Numerical analyses were conducted using a self-developed computational fluid dynamics (CFD) tool, CLiP. The target space was a residential room equivalent to approximately six tatami mats, and multiple device configurations were examined by varying the separation distance and relative placement of the AC and AP.

The results reveal that the installation distance between the devices significantly influences airflow distribution and temperature uniformity within the room. In dispersed configurations, where the AC and AP were placed far apart, high airflow velocities near the floor level of 0.67-0.69 m⁄s were maintained. In contrast, closely spaced configurations led to direct interference between the exhaust flows, resulting in an approximately 12 % reduction in airflow velocity. In particular, when the AP was installed directly beneath the AC, upward airflow velocity decreased to approximately 0.35 m⁄s, corresponding to a 47-49 % reduction compared with the dispersed configuration, due to frontal collision of the exhaust jets. These airflow characteristics directly affected particle transport and removal behavior.

However, contrary to the assumption of strong gravitational influence, pollen particles (apparent density: 140 kg⁄m³) were found to be primarily transported by airflow, with gravitational settling being limited. Consequently, the deposition rate on floor and wall surfaces was low, approximately 8-10 %, across all configurations. The pollen capture efficiency remained high, ranging from approximately 56 % in the interfering configuration to a maximum of 64 % in the dispersed configuration. Similarly, fine allergen particles with a diameter of 1 μm remained suspended and achieved consistently high capture efficiencies of approximately 64-67 %.

These findings indicate that both pollen and allergen particles can be removed effectively regardless of the specific layout. However, to simultaneously optimize thermal comfort and air purification efficiency, it is recommended to select placement strategies that minimize airflow interference and promote whole-room circulation.

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This study examined the validity of the sampling time specified in the official method for indoor air testing, considering differences in the emission characteristics of indoor air chemicals. Parallel measurements were conducted in three residential houses, using the official 24-hr sampling method and a cumulative split sampling method consisting six repeated 4-hr samplings. Quantitative consistency between the two methods was generally confirmed for both TVOC and individual VOCs. Emission characteristics were broadly classified into steady-state, temporal, and complex types. For steady-state VOCs detected in this study, representative concentrations could be reasonably evaluated even with 4-hr sampling. In contrast, temporal and complex-types exhibited diurnal variation, and the variations were averaged only through 24-hr sampling, as observed for TVOC. Overall, 24-hr sampling based on the official method was confirmed to be appropriate for comprehensively evaluating VOCs concentrations in indoor air with diverse emission characteristics using a single sampling event.

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Early diagnosis of cancer is a pressing issue to reduce the mortality rate. Advances in technology for analysis of trace components since the late 1980s have contributed to realizing differences in the quantity of volatile organic compounds (VOCs) in exhaled breath between cancer patients and healthy subjects, meaning that exhaled breath may be applied for early diagnosis of carcinoma. This review describes the generation mechanisms of oncogenesis and VOCs with carcinogenesis in exhaled breath, and the techniques of measurement and evaluation for VOCs in breath. While gas chromatography - mass spectrometry is often employed for analyzing VOCs in exhaled breath, recently techniques using soft ionization have also been applied. Each of measured VOCs is evaluated using various statistical and data processing techniques for biomarker identification. Various aliphatic and aromatic hydrocarbons and aldehydes have been identified as common biomarkers for carcinoma, and other types of VOCs have also been determined. Recently, sensor arrays or electronic nose technologies with pattern recognition for exhaled VOCs, which are in the early stage of practical application, have allowed to discriminate cancer patients from healthy subjects without identifications of each substance. Further research for discrimination methods with breath will ensure the early diagnosis method for carcinoma as an alternative to conventional methods.

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Estimation of "permissible upper-bound concentration (PUC)" of 12 trace elements (V, Cr, Mn, Ni, inorganic As (iAs), Se, Sr, Mo, Ag, Cd, Sb and Ba) in house dust for preventing excess health risk for children was attempted. Upper-bound intakes from diet (including drinking water) and soil were estimated from the published data for each of the trace elements. They were subtracted from the corresponding tolerable daily intake (TDI) and the residual intake was divided by upper-bound house dust ingestion rate (100 mg/day) of the US EPA to find "PUC". The "PUC" could not be found for iAs, Se, Mo and Cd because their upper-bound dietary intake levels exceeded TDI. The "PUC" of the rest of the elements (unit: µg/g) were V (9.4×10²), Cr (4.5×10³), Mn (1.9×10²), Ni (1.6×10³), Sr (6.8×10⁴), Ag (9.0×10²), Sb (50), Ba (3.1×10⁴). The reported 95 %tile concentrations of Mn (551 µg/g) in house dust exceeded the "PUC", and those of Sb and Ni had relatively small margin. Since the "PUC" was estimated as highly conservative upper-bound value, no immediate harm was expected for the exposure to these trace metals via the house dust ingestion. However, it may be warranted to pay some attention to the levels of these elements in house dust.

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The tracer gas method has been well established for measuring air change rates in residential and other building spaces. Owing to its versatility, the method has recently been applied to spaces beyond conventional buildings, including relatively small-scale environments such as clothing, footwear, and domestic refrigerators. Traditionally, the air change rate of such small spaces has been used primarily as an indicator for product performance evaluation. However, small enclosed or semi-enclosed spaces can also serve as sites for the generation, accumulation, and emission of odorous substances and volatile compounds, suggesting that the air change rate may represent an important environmental parameter for understanding their behavior. This paper reviews previous studies in which the tracer gas method was applied to measure air change rates in small-scale spaces and discusses the significance of characterizing their ventilation properties, as well as the potential applications of this approach in the field of indoor environment.

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