Underground shopping malls (USMs) are often open or semi-open environments with interconnected passageways, resulting in the sharing of indoor air. However, indoor air quality (IAQ) within these ...spaces can vary due to many diverse emission sources. We investigated the relationships between IAQ and geographical areas, as well as IAQ and store types, within USMs, in Korea.
In 2020, we studied 10 different USMs, with a total of 128 outlets. We conducted comprehensive IAQ assessments (including measurements of fine particles (PM2.5), aldehydes, and volatile organic compounds (VOCs)) in stores, passages, and outdoor areas. The stores were categorized into three types: clothing, fashion accessories, and food services. Additionally, we measured environmental factors such as CO2 levels and presence of storefront walls.
PM2.5 levels were higher outdoors, whereas aldehyde and VOC levels exhibited elevations within passages and the interior of stores than in the outdoor environment. The store-to-passage ratios for PM2.5, individual aldehydes, and VOC concentrations ranged from 1.06 to 4.93. Formaldehyde and total VOC (TVOC) concentrations were found to be elevated in clothing and fashion accessory stores, whereas PM2.5 concentrations were more prominent in food service establishments. Specific individual compounds, including propionaldehyde, hexaldehyde, benzene, n-heptane, toluene, n-octane, xylene, d-limonene, n-undecane, n-dodecane, and ethylbenzene concentrations exhibited associations with store types. Multivariate regression models demonstrated positive associations between most aldehydes and VOCs with CO2 concentrations and presence of storefront walls.
This study underscored variations within USMs based on area and store type. Aldehyde and VOC concentrations were notably higher in clothing and fashion accessory stores than in food service outlets; these elevations were closely linked to CO2 levels and presence of storefront walls. These findings suggest that monitoring CO2 levels within USM stores, optimizing air-conditioning systems, and designing future stores without storefront walls can collectively contribute to an overall improvement of IAQ within USMs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Purpose
Nonunion is the most frequent cause of reoperation and is associated with high morbidity after distal femur fracture (DFF). We examined the rates of nonunion requiring reoperation after ...fixation for DFF using a locking compression plate (LCP) or retrograde intramedullary nail (RIMN).
Methods
We included four studies comparing LCP and RIMN and 38 single-cohort studies reporting LCP or RIMN. In total, 2156 femurs were included and 166 non-unions were detected. We conducted a pair-wise meta-analysis (with a fixed-effects model) on the four comparative studies and a proportional meta-analysis on the 38 articles to estimate the nonunion rate. We performed sensitivity analysis by comparing studies using LCP with less invasive surgical systems (LISS) with those that used RIMN.
Results
The pairwise meta-analysis showed a similar nonunion rate between the groups odds ratio: 1.02; 95% confidence interval (CI) 0.94–1.11,
p
= 0.633. According to proportional meta-analysis, the pooled prevalence of nonunion was 5% (95% CI 4–7) totally, 6% (95% CI 4–8) in the LCP group, and 4% (95% CI 2–6) in the RIMN group (heterogeneity:
p
= 0.105). According to the sensitivity analysis, there was no difference in the union rate. The pooled prevalence of nonunion from sensitivity analysis was 4 % (95% CI, 3–5); it was 4% (95% CI, 3–6) in LCP with LISS and was 4% (95% CI, 2–6) in RIMN group (heterogeneity:
p
= 0.941).
Conclusion
Approximately 5% of patients who underwent LCP or RIMN fixation developed nonunion. Therefore, LCP and RIMN are effective DFF techniques and mastering one of them is essential.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper introduces the design and fabrication progress of a megawatt class 2G high temperature superconductor (HTS) motor for the ship propulsion application at Doosan Heavy Industries and ...Construction. The purpose of this 2G HTS propulsion motor is to launch the business area for marine applications such as surface ship, submarine, merchant ship etc. The principles and interpretation of the magnetic field for 2G HTS motor and permanent magnet type motors are similar on the basis of 3D design and production. The most important component of an HTS motor is the rotor, which is composed of HTS coil, non-ferrous metal, torque disk, damper, and hollow shaft. A HTS rotor using hastelloy-based 2G HTS coils was designed and built. Open-circuit and short-circuit characteristics of the superconducting motor were investigated and compared with the analysis results at reduced excitation to verify the design. Preliminary testing of a 2G HTS motor has been conducted at a few hundred kilowatts as per the design. Through these results, we anticipate that most of the design criteria can be satisfied. However, we have faced several issues during the testing of the motor and these issues need to be resolved in order to take the design further.
Abstract
Among the transition metal dichalcogenides (TMD), tungsten disulfide (WS
2
) and molybdenum disulfide (MoS
2
) are promising sulfides for replacing noble metals in the hydrogen evolution ...reaction (HER) owing to their abundance and good catalytic activity. However, the catalytic activity is derived from the edge sites of WS
2
and MoS
2
, while their basal planes are inert. We propose a novel process for N-doped TMD synthesis for advanced HER using N
2
+ Ar + H
2
S plasma. The high ionization energy of Ar gas enabled nitrogen species activation results in efficient N-doping of TMD (named In situ-MoS
2
and In situ-WS
2
). In situ-MoS
2
and WS
2
were characterized by various techniques (Raman spectroscopy, XPS, HR-TEM, TOF–SIMS, and OES), confirming nanocrystalline and N-doping. The N-doped TMD were used as electrocatalysts for the HER, with overpotentials of 294 mV (In situ-MoS
2
) and 298 mV (In situ-WS
2
) at a current density of 10 mA cm
−2
, which are lower than those of pristine MoS
2
and WS
2
, respectively. Density functional theory (DFT) calculations were conducted for the hydrogen Gibbs energy (∆G
H
) to investigate the effect of N doping on the HER activity. Mixed gas plasma proposes a facile and novel fabrication process for direct N doping on TMD as a suitable HER electrocatalyst.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This paper describes the design and fabrication progress of a MW-class 2G high-temperature superconductor (HTS) motor for the ship propulsion application at Doosan Heavy Industries and Construction. ...The most important component of an HTS motor is the rotor, which is composed of HTS coil, torque disk, damper, and hollow shaft. The HTS rotor using hastelloy-based 2G HTS coils was designed and built. Open-circuit and short-circuit characteristics of the superconducting motor were investigated and compared with the analysis results at reduced excitation to verify the design. Preliminary testing of a 2G HTS motor has been conducted at a few hundred kW as per the design. Through these results, we verified that most of the design criteria could be satisfied.
Mesenchymal stem cells (MSCs) are of particular interest for the treatment of immune-related diseases owing to their immunosuppressive properties. In this study, we aimed to identify the effect of ...interferon (IFN)-γ priming on immunomodulation by MSCs and elucidate the possible mechanism underlying their properties for the clinical treatment of allogeneic conflicts. Infusion of MSCs primed with IFN-γ significantly reduced the symptoms of graft-versus-host disease (GVHD) in NOD-SCID mice, thereby increasing survival rate when compared with naïve MSC-infused mice. However, infusion of IFN-γ-primed MSCs in which indoleamine 2,3-dioxygenase (IDO) was downregulated did not elicit this effect. The IDO gene was expressed in MSCs via the IFN-γ-Janus kinase (JAK)-signal transducer and activator of transcription 1 (STAT1) pathway, and the infusion of IDO-over-expressing MSCs increased survival rate in an in vivo GVHD model, similar to infusion of IFN-γ-primed MSCs. These data indicate that IFN-γ production by activated T-cells is correlated with the induction of IDO expression in MSCs via the IFN-γ-JAK-STAT1 pathway, which in turn results in the suppression of T-cell proliferation. Our findings also suggest that cell therapy based on MSCs primed with IFN-γ can be used for the clinical treatment of allogeneic conflicts, including GVHD.
•IFN-γ priming enhances the immunosuppressive properties of human MSCs in in vitro and in vivo models.•IFN-γ priming induces IDO expression in MSCs via the JAK/STAT1 signaling pathway, but TLR3 activation does not.•Cell therapy using MSCs primed with IFN-γ could be highly effective in treating allogeneic diseases, including GVHD.
It is necessary to improve the function of mesenchymal stem cells (MSCs) to maximize their treatment potential beyond what is currently achieved in cell therapy studies using naïve heterogeneous MSCs. The preclinical study of a candidate cell therapy based on MSCs primed with interferon-γ as reported in this study, could lay the foundation for the use of cell therapy for the treatment of graft-versus-host disease (GVHD), and is very important for the initiation of clinical trials. Our findings also suggest that cell therapy based on functionally improved MSCs could be used for the clinical treatment of allogeneic conflicts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Predicting the output power of wind generators is essential to improve grid flexibility, which is vulnerable to power supply variability and uncertainty. Digital twins can help predict the output of ...a wind turbine using a variety of environmental data generated by real-world systems. This paper dealt with the development of a physics-based output prediction model (P-bOPM) for a 10 MW floating offshore wind turbine (FOWT) for a digital twin. The wind power generator dealt with in this paper was modeled considering the NREL 5 MW standard wind turbine with a semi-submersible structure. A P-bOPM of a 10 MW FOWT for a digital twin was designed and simulated using ANSYS Twin Builder. By connecting the P-bOPM developed for the digital twin implementation with an external sensor through TCP/IP communication, it was possible to calculate the output of the wind turbine using real-time field data. As a result of evaluating the P-bOPM for various marine environments, it showed good accuracy. The digital twin equipped with the P-bOPM, which accurately reflects the variability of the offshore wind farm and can predict the output in real time, will be a great help in improving the flexibility of the power system in the future.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
9.
Fingerprint ridges allow primates to regulate grip Yum, Seoung-Mok; Baek, In-Keun; Hong, Dongpyo ...
Proceedings of the National Academy of Sciences - PNAS,
12/2020, Volume:
117, Issue:
50
Journal Article
Peer reviewed
Open access
Fingerprints are unique to primates and koalas but what advantages do these features of our hands and feet provide us compared with the smooth pads of carnivorans, e.g., feline or ursine species? It ...has been argued that the epidermal ridges on finger pads decrease friction when in contact with smooth surfaces, promote interlocking with rough surfaces, channel excess water, prevent blistering, and enhance tactile sensitivity. Here, we found that they were at the origin of a moisture-regulating mechanism, which ensures an optimal hydration of the keratin layer of the skin for maximizing the friction and reducing the probability of catastrophic slip due to the hydrodynamic formation of a fluid layer. When in contact with impermeable surfaces, the occlusion of the sweat from the pores in the ridges promotes plasticization of the skin, dramatically increasing friction. Occlusion and external moisture could cause an excess of water that would defeat the natural hydration balance. However, we have demonstrated using femtosecond laser-based polarization-tunable terahertz wave spectroscopic imaging and infrared optical coherence tomography that the moisture regulation may be explained by a combination of a microfluidic capillary evaporation mechanism and a sweat pore blocking mechanism. This results in maintaining an optimal amount of moisture in the furrows that maximizes the friction irrespective of whether a finger pad is initially wet or dry. Thus, abundant low-flow sweat glands and epidermal furrows have provided primates with the evolutionary advantage in dry and wet conditions of manipulative and locomotive abilities not available to other animals.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Most sick building syndrome (SBS) studies have been conducted on workers in office buildings, whereas those assessing store workers in underground shopping districts (USDs) are limited. The purpose ...of this study was to determine the relationship between SBS symptoms of USD store workers and subjective–objective indoor air quality (IAQ). In 2020, 128 stores across 10 USDs in Korea were assessed. One worker in each store was asked about 16 SBS symptoms and seven subjective IAQ perceptions (categorized into two levels Yes or No) via questionnaire. Objectively, indoor concentrations of aldehydes and volatile organic compounds (VOCs) were measured in each store. The prevalence of SBS symptoms within the previous month was 16.4%, 39.1%, 28.9%, and 43.8% for skin, eye irritation, respiratory, and general symptoms, respectively. IAQ perceptions were correlated with the concentrations of several aldehyde compounds and VOCs. After adjusting for demographic (e.g., sex, age, or education) and job-related variables (e.g., working hours), logistic regression models showed all SBS symptom groups (except skin) were significantly associated with IAQ perception. Environmentally, eye irritation symptoms were associated with n-butanol, n-heptane, and xylene; respiratory symptoms with n-heptane; and general symptoms with benzene, n-heptane, and decanal concentrations. The association of SBS symptoms with aldehyde compounds and VOCs suggests that the chemical levels in USD stores may require further control to reduce these symptoms in workers. As controlling the products sold or cooking activities within USDs is difficult, increasing ventilation rates or using low-VOC-emission building materials may be more practical.
•Sick building syndrome was assessed for underground shopping districts in Korea.•>20% of workers in USDs experienced SBS symptoms within the previous month.•Subjective and objective indoor air quality showed similar associations with SBS.•The presence of indoor chemicals can cause SBS in USD store workers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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