Blank Plate Research Articles

Fabrication of a coral-like barium titanate nano-piezoelectric coating and its effect on promoting osteogenic differentiation of rat bone marrow mesenchymal stem cells in vitro

Objective: To investigate the biocompatibility of coral-like barium titanate nano-piezoelectric coatings and the influence of ultrasound-excited piezoelectric effect on the early osteogenic differentiation. Methods: The barium titanate nano-piezoelectric coating (the coating group) was prepared on the surface of titanium metal by anodic oxidation, hydrothermal reaction and high-temperature annealing, and polished titanium specimens were used as control group. The surface morphology, composition, and crystal phase and hydrophilicity of the two groups of titanium specimens were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and contact angle meter. The piezoelectric properties of the materials were characterized by piezoresponse force microscopy. Rat bone marrow mesenchymal stem cells (BMSC) were cultured and identified and seeded the surface of titanium specimens in two groups. The cells seeded on blank culture plates were used as blank group. After low intensity pulsed ultrasound intervention, cell proliferation and live/dead staining were detected to evaluate cytocompatibility of the coatings. Alkaline phosphatase (ALP) activity of each group was detected by ALP staining kit, and the expression of osteogenesis-related genes [integrin, bone morphogenetic protein 2 (BMP-2), Runt-related transcription factor 2 (RUNX2)] was detected by real-time fluorescent quantitative PCR (RT-qPCR) to evaluate the effect of the coating on promoting the early osteogenic differentiation of BMSC. Results: The surface of titanium specimens in the coating group showed a uniform coral-like morphology, and the diameter of the coral tentacles was 70-100 nm. The main component was tetragonal barium titanate. The surface hydrophilicity of the coating group (water contact angle 10.12°± 0.93°) was significantly better than that of the control group (water contact angle 78.32°±0.71°) (F= 10 165.91, P<0.001). The coating has a stable piezoelectric property with a piezoelectric constant of about 5 pC/N. Cell experiments showed that, with or without ultrasound, the cell proliferation activity of the coating group was significantly lower than that of the blank group and the control group on the third day (P<0.05). On the fifth day, with or without ultrasound, there was no significant difference in cell proliferation activity between the three groups (P>0.05). After 7 days of culture, the ALP activity of the coating group was significantly higher than that of the blank group and the control group (P<0.05). The results of RT-qPCR showed that the mRNA expression of integrin and BMP-2 in the coating group with ultrasound was significantly higher than that in the other groups with ultrasound, and was higher than that of the coating group without ultrasound (P<0.05). The expression of integrin mRNA in the control group with ultrasound was significantly higher than that in the control group without ultrasound (P<0.05). The expression of RUNX2 mRNA in the coating group with ultrasound was significantly higher than that in the coating group without ultrasound (P<0.05). Conclusions: The coral-like barium titanate nano-piezoelectric coating exhibits favorable biocompatibility and stable piezoelectric property, and facilitates the early osteogenic differentiation of BMSC under the excitation of low-intensity pulsed ultrasound.

Eaten beauty needs replenishing: The impact of beautiful plate patterns on plate waste

This study explored the influence of food aesthetics on plate waste and the underlying mechanisms through which plate patterns can reduce food waste. Three studies were conducted to examine the potential differences in beauty decrement (i.e. aesthetically vulnerable vs. aesthetically invulnerable) across various food categories and to evaluate the effectiveness of plate patterns in reducing food waste.Study 1 revealed that certain foods were more susceptible to significant beauty decrements during consumption. Study 2 demonstrated that foods vulnerable to aesthetic degradation were more likely to be wasted than those that were aesthetically invulnerable. Additionally, among the aesthetically vulnerable foods, those with a perfect appearance were wasted more frequently than those with an imperfect appearance. Study 3 (A) showed that less aesthetically vulnerable foods were wasted when served on patterned plates than when served on blank plates. Study 3 (B) replicated the findings of Study 3 (A) by conducting an actual eating task in a laboratory and validating the chain mediation model for the impact of plate patterns on food waste. Specifically, plate patterns influenced the reduction in perceived beauty during food consumption, affecting consumer enjoyment and ultimately resulting in plate waste.

Topical blood products modulate the effects of ophthalmic antibiotics against common bacterial pathogens in dogs with infectious keratitis.

Bacterial keratitis is a common and serious condition that often leads to vision impairment and potential loss of the eye if not treated promptly and adequately. Topical blood products are often used concurrently with topical antibiotics, helping to mitigate corneal 'melt' from proteases released on the ocular surface. However, blood products are rich in albumin and could affect the efficacy of antibiotics due to drug-protein binding. In this study, serum and plasma samples were harvested from 10 healthy dogs and 10 healthy horses, obtaining fresh and frozen (1 month at -20°C) aliquots for in vitro experiments. Albumin levels were quantified using species-specific ELISA kits. Thirty bacteria (10 Staphylococcus pseudintermedius, 10 Streptococcus canis, 10 Pseudomonas aeruginosa), isolated from canine patients with infectious keratitis, were each tested with blank plates as well as commercial susceptibility plates (Sensititre™ JOEYE2) to assess the minimal inhibitory concentration (MIC) of 17 different antibiotics in the absence (control) or presence of eight test groups: serum or plasma (fresh or frozen) from canines or equines. Albumin concentrations ranged from 13.8-14.6 mg/mL and 25.9-26.5 mg/mL in canine and equine blood products, respectively. A direct antimicrobial effect was observed mostly with equine vs. canine blood products (specifically serum and to a lesser degree plasma), and mostly for Staphylococcus pseudintermedius isolates. MICs generally increased in the presence of blood products (up to 10.8-fold), although MICs also decreased (down to 0.25-fold) for selected antibiotics and ocular pathogens. Median (range) fold changes in MICs were significantly greater (p = 0.004) with the canine blood products [2 (0.67-8.1)] than the equine blood products [2 (0.5-5)]. In practice, clinicians should consider equine over canine blood products (lesser impact on antimicrobial susceptibility), serum over plasma (greater antimicrobial effects), and administering the blood product ≥15 min following the last antibiotic eyedrop to minimize the amount of albumin-antibiotic binding in tear film.

Enhanced light-to-thermal conversion performance of self-assembly carbon nanotube/graphene-interconnected phase change materials for thermal-electric device

Solar energy conversion and storage technologies have attracted more attention to alleviate the energy crisis and ecological concern. Further improvement on the thermal conductivity and photothermal storage capacity of phase change materials (PCMs) remain a huge challenge. In this work, a new composite PCMs employing carbon-based (CRGO) aerogel as the supporting material and paraffin wax (PW) as the PCM was prepared. We achieve a three-dimensional (3D) porous interconnected structure by cross-linking carbon nanotubes (CNT) with reduced graphene oxide (rGO). This 3D structure could provide more heat transfer channels and effective contact interfaces, resulting in its enhanced thermal conductivity. The aspect ratio of CNT and the ratio of CNT and rGO is regulated to optimize the 3D thermal conductive skeleton for CRGO aerogel. As a result, the multi-layer CRGO aerogel composite PCMs exhibited high solid-liquid phase change enthalpy (146.7 J/g) and excellent phase change stability. Optimal incorporation of 30 % CNT increased the thermal conductivity to 1.27 W/(m·K), which is 452 % higher than that of the pure PW. Meanwhile, a photothermal conversion efficiency of up to 90.3 % was achieved for the composite PCMs. In addition, the output voltage of the solar-thermal-electric device based on composite PCMs (150 mV) is about 3.75 times that of the blank plate (40 mV) under solar radiation. Therefore, CRGO aerogel composite PCMs show great promise for efficient solar-thermal-electric energy conversion utilization.

Preparation of NH4Cl-Modified Carbon Materials via High-Temperature Calcination and Their Application in the Negative Electrode of Lead-Carbon Batteries.

The performance of lead-acid batteries could be significantly increased by incorporating carbon materials into the negative electrodes. In this study, a modified carbon material developed via a simple high-temperature calcination method was employed as a negative electrode additive, and we have named it as follows: N-doped chitosan-derived carbon (NCC). The performance of this material was compared with a control battery containing activated carbon (AC). X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy were engaged in analyzing the crystal structure and morphology of the material. Afterwards, the electrochemical and battery performance was examined through cyclic voltammetry (CV), linear voltammetry (LSV) and constant current charge-discharge testing. Markedly, the electrode plate containing 1 wt.% NCC indicates the highest specific capacity (106.48 F g-1) as compared to the control battery, which is 1.56 times higher than the AC electrode plate and 4.75 times higher than the blank electrode plate. The linear voltammetry shows that the hydrogen precipitation current density of the 1 wt.% NCC electrode plate is only -0.028 A cm-2, a much higher value than that of the AC electrode plate. In addition, the simulated battery containing 1 wt.% NCC has a cycle life of 4324 cycles, which is 2.36 times longer than that of the same amount of additive AC battery (1834 cycles) and 5.34 times longer than that of the blank battery (809 cycles). In summary, NCC carbon has the advantage of extending the life of lead-acid batteries, rendering it a promising candidate for lead-acid battery additives.

Piezoelectric PDMS/AlN Film for Osteogenesis in Vitro.

Bone defect and nonunion are complex diseases which are difficult to treat due to insufficient bone regeneration. Electrical stimulation has attracted attention as a promising strategy to induce and enhance bone regeneration. Self-powered and biocompatible materials have been widely explored and used in biomedical devices, owing to their ability to produce electrical stimulation without an external power source. We aimed to prepare a piezoelectric polydimethylsiloxane (PDMS)/aluminum nitride (AlN) film with excellent biocompatibility and osteoconductive ability for the growth of murine calvarial preosteoblast MC3T3-E1 cells. By applying vibration to stimulate body movement, the PDMS/AlN film demonstrated a current density of 2-6 μA cm-2, and the generated continuous alternating current (AC) effectively promoted MC3T3-E1 cell growth, viability, and osteoblastic related gene expression (genes runt-related transcription factor 2 [RUNX2], osteocalcin [OCN], alkaline phosphatase [ALP]) and exhibited higher mineralization. Compared to blank plates and nonvibrated PDMS/AlN films, the vibrated PDMS/AlN film showed rapid and superior osteogenic differentiation. The design of the biocompatible and flexible piezoelectric PDMS/AlN film overcame the poor processability, brittleness, and instability of electrical stimulation of traditional electroactive materials, demonstrating great potential in the application of electrical stimulation for bone tissue engineering.

Corrosion inhibition performance of an environmentally friendly water-based nano-inhibitor

Metal corrosion not only causes huge economic losses, but sometimes even endangers personal safety. Therefore, the requirements for the corrosion resistance of metals are becoming a significant problem. The use of inhibitor is still one of the most common and effective methods to prevent metal corrosion. An environmentally friendly water-based nano-inhibitor containing nano TiO2 was prepared in this work. The open-circuit potential-time curve revealed that the voltage stability value of the steel coated with the proposed inhibitor is −0.51 V, which is higher than −0.54 V of the blank steel plate and commercial inhibitor (-0.52 V), indicating that the proposed nano-inhibitor can improve the stability of the entire system. According to the Tafel polarization curve, the inhibitor coating can significantly increase the corrosion potential, and at the same time reduces the corrosion current density. The EIS plots show that the proposed inhibitor can increase the charge transfer resistance.

Photographic plates and spirit fakes: remembering Harry Price&amp;rsquo;s investigation of William Hope&amp;rsquo;s spirit photography at its centenary

During the opening decades of the twentieth century, William Hope was a well-respected medium amongst the spiritualist community in Britain, with positive endorsements from major scientific figures such as the chemist William Crookes and the author and physician Arthur Conan Doyle. Hope was often seen as one of the few mediums to be able to produce authentic spirit photographs. However, all that changed in late February 1922 when the magician-turned-psychical researcher Harry Price claimed to have caught Hope cheating during a sitting, by discovering that he was swapping blank photographic plates for ones with supposed spirit ‘extras’ already on them. Hope was publicly exposed as a fraud, and what ensued was a major debate between believers and sceptics over the legitimacy of the medium’s alleged spirit photography. The Hope-Price affair became a media sensation in the months that ensued, with a series of articles about the investigation and its aftermath appearing in the major spiritualist magazine Light. While much has been written about the Hope-Price affair as a key example of fake mediumship, most of these accounts tend to prioritise the sceptic’s perspective, with little attention paid to spiritualist responses. This paper will provide a more balanced narrative, focusing on one of the main criticisms of Hope’s defenders at the time: the credibility of Price’s testimony. Because Price actively misled Hope and his associates in a bid to catch the medium cheating, his trustworthiness as an objective observer and investigator of extraordinary phenomena was questioned. Key to this analysis is the essential role material evidence played in this case, with particular emphasis on the photographic technologies and processes used.

Enabling stable cycling performance with rice husk silica positive additive in lead-acid battery

Lead-acid battery has been widely used in stationary energy storages, such as photovoltaic application, grid service and uninterrupted power system due to the advantages of high safety, recyclability, and low cost. However, the low cyclic performance limits its further applications in emerging functions. One of the main failure modes is caused by the high polarization on the PbO2 positive plate. Herein, the rice husk silica with hierarchical porous structure was used as the positive additive for preventing from the high polarization of the PbO2 positive plate. Nitrogen adsorption-desorption isothermal and X-ray diffraction confirmed that the hierarchical porous rice husk silica enlarged the electrochemical surface area of the PbO2 positive plate, endowing a high rate of active material utilization and low polarization during the charging process. Compared with the blank plate, the PbO2 plate with rice husk silica showed improved Coulombic efficiency and a prolonged cycle life. These notable features verify that the porous rice husk silica is a cost-effective positive additive for sustained lead-acid batteries.

Self-supporting copper electrode prepared by ultrasonic impact for hydrogen evolution reaction

Water electrolysis for hydrogen production requires highly active and inexpensive catalysts. Herein, we combine ultrasonic impact nanocrystallization (UIN) technology with nital etching method to rapidly prepare highly efficient self-supporting Cu electrode with abundant low-angle grain boundaries. When used as a catalyst for hydrogen evolution reaction (HER), the as-prepared electrode exhibits an overpotential of 353 mV at a current density of 10 mA cm−2, which is about 200 mV lower than that of the blank Cu plate. Moreover, the overpotential decreased to 246 mV after the stability test of 100 h, indicating a self-optimizing property. This work paves a new way for the preparation of self-supporting electrode with high performance.

Evaluation of bolted CHS flange-plate connections under axial tension

Over the last five decades, many researchers have performed experiments on bolted circular hollow section flange-plate connections. Most of these tests have been on ring flanges, using small- to medium-size tubes, with far fewer on blank flange plates, and typically under axial tension loading. Herein, all international test data pertaining to bolted flange-plate connections in tension is collated, and supplemented by two more large-scale specimens with blank flange-plate connections. Bolt fracture and flange-plate plastification are the two limit states for bolted flange-plate connections, so the database of 98 tests and 33 numerical models is carefully screened to exclude failure modes that do not pertain to the connection. Prior models for predicting the connection capacity under axial tension are reviewed and evaluated. In addition, a modified T-stub prying model is proposed for circular blank flange-plate connections. The notion of using the flange-plate ultimate stress in connection prying models, instead of the traditional approach of using flange-plate yield stress, is also examined. After a reliability analysis, a preferred design method for blank and ring flange-plate connections is recommended.

Comparative Analysis of Steel Plates and PLA Used for Joint Repair in Humans and Canines

The exploration of fracture internal fixation materials has been one of the research hotspots in the field of biomedical materials. The traditional internal fixation material for fracture is metal fixation. Although its mechanical strength is very large, it can not be degraded and absorbed in human body after implantation of human body or canine joint, which requires a secondary operation to remove, which not only brings pain to patients, but also causes economic pay.[1] Therefore, the development of a biodegradable fracture internal fixation material has become the goal of many researchers. Polylactic acid (PLA) is nontoxic and harmless, has good biocompatibility and strong mechanical properties. It can be degraded in vivo after implantation. The degradation products are CO2 and H2O.[2] For the study of the feasibility of polylactic acid as a substitute for common fracture fixation materials ,18 northern Chinese pastoral dogs were randomly divided into blank group, PLA group and plate group. The data were recorded according to the Wakitani score from the first week to the fifteenth week after operation. First, all the indexes were divided into two categories by principal component analysis [3], then the blank group, steel plate group and PLA group were fitted and compared. Finally, it is concluded that PLA is more beneficial to joint repair than steel plate.

Effect of Color Coating of Cover Plate on Thermal Behavior of Flat Plate Solar Collector

An important trend of Building Integrated Solar Thermal (BIST) system is to improve the aesthetic aspect of the solar collector to meet the requirement of architectural style and energy collection. Painting on the glass cover in an appropriate method is a simple and practical way. In this study, a halftone coating was used to print a red brick wall pattern on the glass cover. A series of comparative experiments were carried out to test the effect of the coating on the thermal behavior of the solar collector. In heat collection processes, compared with the solar collector with blank cover plate, the one with coated cover plate has lower absorber plate temperature and higher cover plate temperature. The lower the solar irradiance, the smaller the effect of color coating on the solar collector. Compared with the uncoated surface, the coated surface is more sensitive to solar irradiation. In the same heat collection process, compared with the solar collector coated on the outer surface of the cover plate, the one coated on the inner surface has 0.8 °C higher heat absorber plate temperature and 5% lower top heat loss.

Preparation and Characterization of Akermanite/Merwinite Scaffolds for Bone Tissue Repair

The ceramics in the system CaO–MgO–SiO2 has recently attracted a great deal of attention because they display a good in vitro bioactivity and have potential use as bone implants. Biphasic calcium-magnesium-silicate ceramics were prepared by a sol-gel method. The dried gel with chemical composition 3CaO.MgO.2SiO2 was thermally treated at 1200 °C for 2 hrs. The structural behavior of the synthesized ceramics was examined by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Merwinite crystalline phase and akermanite phase were recognized. Then, porous akermanite/merwinite scaffolds were prepared to utilize polymer sponge method and evaluated by employing SEM. Furthermore, bone marrow stromal cells (BMSC) adhesion and proliferation on the scaffolds were evaluated by MTT assay test. Differentiation of the cells was assessed by measuring alkaline phosphatase (ALP) activity. The results demonstrated that BMSC adhered and spread well on akermanite scaffolds and proliferated with the increase in the culture time, and the differentiation rate of osteoblasts on scaffolds was comparable to that on blank culture plate control. Thus, the obtained results presented that the akermanite/merwinite scaffolds deserve attention for bone tissue engineering applications.

The study of servers’ arrangement and air distribution strategy under partial load in data centers

In recent years, with the rapid development of data centers, its huge energy consumption problem is increasingly prominent. Especially, with the development trend of large-scale data center, the load rate of racks is relatively low, which can easily lead to oversupply of cold capacity, thus resulting in energy waste. Hence, how to reasonably arrange servers so as to effectively utilize cooling capacity and improve energy efficiency has become an urgent problem to be solved. In this paper, field test was made to investigate the thermal environment. The test results indicated that the actual load rate of the data room is between 19.34%˜42.55%, and SHI value for test rows were between 0.128 and 0.594 owning to oversupply of CRACs, as a result of serious mixing of cold air and hot air. To reduce the energy consumption, the cooling capacity of CRACs were equal to IT equipment heat dissipation by using simulation tool through changing the load rate, servers’ arrangement and air distribution strategy under partial load in data centers. The results showed that the servers uniformly distributed in all racks presented good inlet air temperature that fell in the acceptable temperature range by ASHRAE. And it suggests that the servers are uniformly mounted from the middle of the rack and then the upper for low load rates. When the load rate more than 60%, blanking plates need to be installed.

Preparation of a Hierarchically Porous Lead/Carbon Composite and Its Application in Lead‐Carbon Batteries

A novel and scalable lead-modified phenolic resin-based carbon material (Pb/PRC) has been successfully prepared by using lead-modified phenolic resin (Pb/PR) as a precursor, toluene as a pore-forming agent, and KOH as an activating agent. The Pb/PRC composite presents a hierarchically porous nanosphere structure, and this structure contributes to prolong its cycling life under high-rate partial state-of-charge (HRPSoC) operation. Pb/PRC with nano-lead can effectively inhibit hydrogen evolution and provide pseudocapacitance. Compared with a blank negative plate, a lead-carbon battery with Pb/PRC displays 18 000 cycles under HRPSoC operation and exhibits a capacity of 100 mA h g-1 at 2 C discharge rate.

Alpha spectroscopy backgrounds at Lawrence Livermore National Laboratory: technical equivalency for backgrounds with blank plates versus backgrounds with no plates

Alpha spectroscopy chamber backgrounds are routinely measured using blank plates. Operator time spent moving blank plates in and out of chambers is significant. If chamber backgrounds are measured in empty chambers, time spent moving blank plates can be reclaimed for other uses. This study compares results of chamber backgrounds measured with and without plates. Five hundred fourteen chamber backgrounds measured with plates are paired with 514 chamber backgrounds measured without plates. The total counts within 13 spectral regions of interest are compared statistically. Chamber backgrounds measured without blank plates are found statistically equivalent to chamber backgrounds measured with blank plates.

Design of Automatic Loading and Unloading Device for the Fine Blanking of Thick Materials Based on the Humanoid Feeding

In view that there is a high market demands on the precision stamping processing of thick plates and the loading & unloading of thick blank plates in current fine blanking industry of thickness materials are commonly implemented through the manual operation, a complete set of automatic loading and unloading device for the fine blanking of thick materials based on the humanoid feeding is designed. This device mainly consists of hydraulic press, unstacking device, alignment device, humanoid loading device, discharge device for the finished product, humanoid unloading device, etc. It realizes the automatic stacking, automatic unstacking, automatic alignment, automatic loading, automatic oiling, automatic feeding, automatic stamping, automatic discharge of stamping wastes, automatic discharge of the finished stamping products and automatic collection of waste plates, etc., and also basically realizes the automation of the whole process flow of the precision stamping processing of thickness plates.

Preparation of RGO-P25 Nanocomposites for the Photocatalytic Degradation of Ammonia in Livestock Farms

In this paper, the Hummer’s method was used to prepare the compound catalyst of reduced graphene and TiO2 (RGO-P25), and the sand core plate was used as the carrier to provide the theoretical basis for the application of animal environmental purification by exploring the degradation of ammonia in RGO-P25. Characterization results show that the band gap of P25 is reduced from 3.14 eV to 2.96 eV after the combination of RGO, and the recombination rate of the photogenerated electrons and holes also decreased significantly, both resulting in the improvement of ammonia degradation by composite catalysts. Experimental results show that the carrier (sand core plate) and RGO-P25 are effectively stabilized with Si–O–Ti, but the blank core plate carrier could not degrade the ammonia, and its adsorption is not obvious, only 5% ± 1%, under 300 W ultraviolet lamp irradiation, the degradation rates of P25, RGO and RGO-P25 for ammonia at initial concentrations of 119–124 ppm were 72.25%, 81.66% and 93.64%, respectively. P25 dispersed through RGO can effectively adsorb ammonia on the surface to provide a reaction environment and thereby improve its photocatalytic efficiency, thus, endowing the RGO-P25 composites with higher photocatalytic degradation performance than RGO or P25 individually.

First Report of Blue Mold Caused by Penicillium oxalicum in Sweetpotato (Ipomoea batatas) in Korea

Many fungal diseases can affect sweetpotato (Ipomoea batatas [L.] Lam), a dicotyledonous plant in the Convolvulaceae family, at various stages from cultivation through storage (Clark et al. 2013). We observed blue mold disease on sweetpotato storage roots in the store house at the Bioenergy Crop Research Institute, Muan, South Korea, in 2016. The storage temperature and relative humidity were 13°C and 90%, respectively. Infected storage roots showed distinct rot symptoms, and bluish green sporulation was abundantly visible on the surface. Notably, disease was observed on two different local sweetpotato varieties, namely, Yulmi and Jinhongmi. Storage root samples showing rot symptoms were collected and used to isolate the causal organism. Fungi were isolated by the single spore isolation method onto potato dextrose agar (PDA). Repeated culturing of hyphal growth from the infected roots resulted in the isolation of two fungal isolates (SPL15027 and SPL15029). These were examined for morphological and molecular characteristics. Fungal growth on malt extract agar (MEA) at 25°C after 7 days appeared as a dull green center with pale green to white margins and lacked visible secreted pigmentation. The colony diameter on MEA was 37.9 ± 0.19 mm. Conidiophores were 57.3 to 205.2 (140) μm long, 2 to 4 metulae, 11.0 to 22.0 (17.4) μm, and phialides 7.2 to 20.0 (12.5) μm long in diameter. Conidia were globose to subglobose and were borne in columns. Conidial dimensions were 3.5 to 5.5 (4.2) × 2.5 to 4.0 (2.9) μm (n = 25). Morphologically, the pathogen was identified as Penicillium oxalicum Currie & Thom (Kozakiewicz 1992). Polymerase chain reaction (PCR) analysis was used for further molecular identification. Genomic DNA of the isolates was extracted using the Solg Genomic DNA Prep Kit (Solgent, Daejeon, South Korea), followed by PCR analysis using primers specific to the internal transcribed spacer (ITS5/ITS4) and β-tubulin locus (BT2a/BT2b) genes (Jing et al. 2015). Both strands of the purified PCR products were sequenced. These sequences were deposited in GenBank (ITS-KY853419/KY853420 and BT-KY853421/KY853422). BLAST analysis of the ITS (LT797553, KX515788, and HM469410) and BT (KF225064, AB849501, and KU600425) sequences showed 100% homology to P. oxalicum. This confirmed the identity of the isolated organism. Koch’s postulates were fulfilled by using the isolated culture for sweetpotato storage roots inoculations. PDA plugs (5 mm) and 50 μl of 2 × 10⁴/ml conidial suspension were used to infect different sweetpotato varieties including Chuhanmi, Yulmi, Jinhongmi, Yonhwangmi, and Dahomi. PDA plugs from blank plates and sterilized distilled water were used as respective noninoculated controls. Fungal-inoculated storage roots developed typical blue mold symptoms after 10 days of incubation at 25°C and under high humidity. In contrast, no symptoms were observed on noninoculated control storage roots. P. oxalicum was reisolated from the artificially inoculated roots, completing Koch’s postulates. To the best of our knowledge, this is the first report of P. oxalicum causing postharvest blue mold on sweetpotato in Korea.