Fabrication of Carbon Fiber Reinforced Aromatic Polyamide Composites and Their Thermal Conductivities with a h-BN Filler.

In this study, a carbon fiber-reinforced thermoplastic composite was fabricated using a new aromatic polyamide (APA) as a matrix. Non-isothermal crystallization behaviors in the cooling process of APA resin (a semi-crystalline polymer) and composite were analyzed by using a differential scanning calorimeter (DSC). To determine the optimum molding conditions, processing parameters such as the molding temperature and time were varied during compression molding of the Carbon/APA composite. The tensile and flexural properties and morphologies of the fabricated composites were analyzed. Molding at 270 °C and 50 MPa for 5 min. showed relatively good mechanical properties and morphologies; thus, this condition was selected as the optimal molding condition. In addition, to enhance the thermal conductivity of the Carbon/APA composite, a study was conducted to add hexagonal boron nitride (h-BN) as a filler. The surface of h-BN was oxidized to increase its miscibility in the resin, which resulted in better dispersity in the APA matrix. In conclusion, a Carbon/APA (h-BN) composite manufactured under optimal molding conditions with an APA resin containing surface-treated h-BN showed a thermal conductivity more than twice that of the case without h-BN.

Fabrication of Activated Carbon Fibers with Sheath-Core, Hollow, or Porous Structures via Conjugated Melt Spinning of Polyethylene Precursor.

Using polyethylene as carbon precursor, we have fabricated cost-effective carbon fibers with a sheath-core structure via conjugate melt spinning. Low-density polyethylene (LDPE) and high-density polyethylene (HDPE) were used as the sheath and core of the fiber, respectively, while sulfonation with sulfuric acid was conducted to enable the crosslinking of polyethylene. We demonstrated that carbonization and activation of the sheath-core-structured polyethylene fiber can result in a well-developed microporous structure in the sheath layer, and due to the core-sheath structure, the resulting activated carbon fibers exhibit a high tensile strength of ~455 MPa, initial modulus of ~14.4 GPa, and Brunauer-Emmett-Teller (BET) surface area of ~1224 m2/g. Finally, activated carbon fibers with a hollow, sheath-core, and porous were successfully fabricated by controlling the degree of crosslinking of the LDPE/HDPE sheath-core fiber.

Investigation of glucose-6-phosphate dehydrogenase (G6PD) deficiency prevalence in a Plasmodium vivax-endemic area in the Republic of Korea (ROK).

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most prevalent inborn disorder. This X-chromosome-linked recessive disease affects more than 400 million people globally, and is associated with haemolytic anaemia after medication with the anti-latent malaria drug, primaquine. To prevent malaria, the Republic of Korea (ROK) Army administers malaria chemoprophylaxis. Due to the previously low G6PD deficiency prevalence in the ROK, prior to primaquine administration, testing for G6PD deficiency was not mandatory. In this study, to evaluate the risk from malaria chemoprophylaxis in the ROK, G6PD deficiency prevalence was investigated. METHODS: Blood specimens from 1632 soldiers entering training camp for the 3rd Infantry of the ROK Army were collected. CareStart™ Biosensor for G6PD and haemoglobin (Hb) was used to detect G6PD levels. G6PD variants using the DiaPlexC G6PD Genotyping kit (Asian type) and full-length sequencing were examined. RESULTS: Of 1632 blood specimens tested, none was observed to be G6PD deficient. The median value of all tested samples was 7.582 U/g Hb. An investigation of 170 G6PD DNA variants was analysed and categorized as partially low normal [n = 131, 30-80% (2.27-6.05 U/g Hb) of the median value], high [n = 3, > 150% (> 11.373 U/g Hb) of the median value], or normal [n = 36, 80-150% (6.05-11.373 U/g Hb) of the median value], and none was amplified by the DiaPlexC kit. Five silent mutations (C→T) in 131 partially low normal specimens were found at the 1311th nucleotide position by sequence analysis. Another 8 silent mutations (T93C) were also detected in 131 partially low normal specimens. Thus, it is inferred that these silent mutations could be related to G6PD activity. CONCLUSIONS: This G6PD deficiency prevalence study, conducted among participants from the 3rd Infantry of the ROK Army, provided crucial evidence for the safety of malaria chemoprophylaxis. This study showed that the prevalence of G6PD deficiency among 1632 young soldiers was wholly absent. Although G6PD phenotypic mutations were not detected, many silent mutations (C1311T and T93C) were observed. Thus, it is inferred that malaria chemoprophylaxis is relatively safe against G6PD deficiency-mediated haemolytic anaemia. However, given the number of individuals whose G6PD were at the partially low normal range and the frequent detection of G6PD deficiency-related mutations, consistent monitoring of G6PD deficiency is needed.

Comparative Analysis of Primer-Probe Sets for RT-qPCR of COVID-19 Causative Virus (SARS-CoV-2).

Coronavirus disease 2019 (COVID-19) is a newly emerging human infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, also previously known as 2019-nCoV). Within 8 months of the outbreak, more than 10,000,000 cases of COVID-19 have been confirmed worldwide. Since human-to-human transmission occurs easily and the rate of human infection is rapidly increasing, sensitive and early diagnosis is essential to prevent a global outbreak. Recently, the World Health Organization (WHO) announced various primer-probe sets for SARS-CoV-2 developed at different institutions: China Center for Disease Control and Prevention (China CDC, China), Charité (Germany), The University of Hong Kong (HKU, Hong Kong), National Institute of Infectious Diseases in Japan (Japan NIID, Japan), National Institute of Health in Thailand (Thailand NIH, Thailand), and US CDC (USA). In this study, we compared the ability to detect SARS-CoV-2 RNA among seven primer-probe sets for the N gene and three primer-probe sets for the Orf1 gene. The results revealed that "NIID_2019-nCOV_N" from the Japan NIID and "ORF1ab" from China CDC represent a recommendable performance of RT-qPCR analysis for SARS-CoV-2 molecular diagnostics without nonspecific amplification and cross-reactivity for hCoV-229E, hCoV-OC43, and MERS-CoV RNA. Therefore, the appropriate combination of NIID_2019-nCOV_N (Japan NIID) and ORF1ab (China CDC) sets should be selected for sensitive and reliable SARS-CoV-2 molecular diagnostics.

Efficacy and Safety of Caregiver-Mediated Exercise in Post-stroke Rehabilitation.

OBJECTIVE: To assess the efficacy and safety of our 4-week caregiver-mediated exercise (CME) in improving trunk control capacity, gait, and balance and in decreasing concerns about post-stroke falls when there is an increase in its efficacy. METHODS: Acute or subacute stroke survivors were assigned to either the trial group (n=35) or the control group (n=37). Changes in Modified Barthel Index (MBI), Functional Ambulation Categories (FAC), Berg Balance Scale (BBS), and Trunk Impairment Scale (TIS) scores at 4 weeks from baseline served as primary outcome measures. Correlations of primary outcome measures with changes in Fall Efficacy Scale-International (FES-I) scores at 4 weeks from baseline in the trial group served as secondary outcome measures. Treatment-emergent adverse events (TEAEs) served as safety outcome measures. RESULTS: There were significant differences in changes in MBI, FAC, BBS, TIS-T, TIS-D, TIS-C, and FES-I scores at 4 weeks from baseline between the two groups (all p<0.0001). There were no significant (p=0.0755) differences in changes in TIS-S scores at 4 weeks from baseline between the two groups. MBI, FAC, BBS, and TIS scores showed significantly inverse correlations with FES-I scores in patients receiving CME. There were no TEAEs in our series. CONCLUSION: CME was effective and safe in improving the degree of independence, ambulation status, dynamic and static balance, trunk function, and concerns about post-stroke falls in stroke survivors.

Necessity to develop a tool to evaluate activity of daily living for electric powered indoor/outdoor chair users.

OBJECTIVE: To evaluate changes in activity of daily living before and after provision of electric-powered indoor/outdoor chair (EPIOC), discuss problems of current activities of daily living (ADL) evaluating tools for EPIOC users, and provide preliminary data to develop ADL evaluation tool for EPIOC user. METHODS: A total of 70 users who were prescribed EPIOC and had been using for more than 1 year were recruited in this study. Before and after provision of EPIOC, MBI and FIM scores were measured and a questionnaire consisting of six categories (general socioeconomic states, currently using state, whether EPIOC was helpful for social participation and occupational chances, psychiatric influences, self-reported degrees of independency, and barriers of using EPIOC) was used. RESULTS: No difference in MBI scores before and after provision of EPIOC was observed. However, the wheelchair ambulation category showed a significant difference. While motor FIM was not significantly different from MBI, FIM score were significantly (p<0.05) higher than MBI. For questions regarding social participation frequency, helpfulness of EPIOC on confidence, refreshing patients' emotions and self-reported degrees of independence, all of them showed positive responses. Especially, EPIOC users' self-reported degree of independency showed favorable results. There was discrepancy in MBI or FIM measured by physicians. CONCLUSION: Our study showed that there was a gap between the existing ADL evaluation tool and the ADL level that EPIOC users were actually feeling. Thus, it is necessary to develop an evaluation tool specifically for EPIOC.

Development of in-cell imaging assay systems for MMP-2 and MMP-9 based on trans-localizing molecular beacon proteins.

A sensitive in-cell imaging MMP-2 and MMP-9 detection systems that enables direct fluorescence detection of a target protease and its inhibition inside living cells has been developed. This in-cell imaging system utilizes the concept of fluorescent molecular beacon reporter (MBR) protein comprising a masking protein, a mitochondrial targeting sequence, a protease specific cleavage sequence and a fluorescent marker sequence, green fluorescent protein (GFP). The MBR protein is designed to change its intracellular location upon cleavage by either MMP-2 or MMP-9 from cytosol to mitochondria. Full and partial MMP-2 and MMP-9 were tested for optimal expression and activity in the cell. The activity of MMP-2 and MMP-9 was approximately 65-71%. Among MMP clones, MMP-2 catalytic domain and MMP-9 clone containing pro, catalytic and hemopexin domain were most active. Both MMP-2 and MMP-9 required divalent ions Ca and Zn for its activity and MMP-9 was more active at higher Ca/Zn ratio. With the in-cell imaging assay the protease activity can be measured in cellular environment and cellular toxicity of candidate molecules can be monitored at the same time. These are great advantage when compared to other currently used in vitro biochemical assays. The in-cell imaging assay developed in this study can be modified for other MMPs and can be used in various life science and drug discovery researches including the high throughput screening and high contents screening applications.

Decreased cellular levels of palmitic amide are linked to 5-fluorouracil resistance in human colon cancer cells.

BACKGROUND/AIMS: The aim of this study was to investigate whether profiling metabolic compounds in human colon cancer cells with induced 5-florouracil resistance enables identification of predictive biomarkers for 5-florouracil resistance. METHODOLOGY: 5-florouracil resistant and parental cells were extracted using methanol/chloroform solution, and analyzed by MALDI-TOF. Principal components analysis and discriminant analysis was performed to select low-mass ions with strong discriminating power between 5-florouracil resistant and parental cells. The correlation between the intensities of low-mass ions and intrinsic 5-florouracil resistance in 11 colon cancer cells was analyzed using the Spearman rank coefficient. RESULTS: Eleven low-mass ions had strong discrimi-nating power between 5-florouracil-resistant and parental cells. Of these, the intensity of a low-mass ion with 256.29 m/z was negatively correlated with intrinsic 5-florouracil resistance in 11 colon cancer cells (r = -0.6545, P = 0.0338). By searching the H+ adduct with 0.05 m/z tolerance in the Human Metabolome Database, a low-mass ion of 256.29 m/z was identified as palmitic amide. Interestingly, extracellular treatment with palmitic amide reduced 5-florouracil resistance and invasiveness in 5-florouracil-resistant cells. CONCLUSIONS: Palmitic amide showed potential not only as a predictor of 5-florouracil resistance, but also for reduction of 5-florouracil resistance in colon cancer cells.

Fast on-site diagnosis of influenza A virus by Palm PCR and portable capillary electrophoresis.

A method combining Palm polymerase chain reaction (PCR) and portable capillary electrophoresis (CE) was developed for rapid on-site analysis of influenza A (H1N1) virus. The portable CE system was suitable for rapid diagnosis which was able to detect a sample in ∼4 min after sample loading, while the 'Palm PCR' system allowed for high-speed nucleic acid amplification in ∼16 min. The analysis time from DNA sample to analysis of amplified target DNA molecule was only ∼20 min, which was significantly less than slab gel electrophoresis with other commercially available PCR machine. When the 100-bp DNA ladder was separated, the relative standard deviation values (n=5) for the migration times and peak areas of the 100 and 200-bp DNA molecules were 0.26 and 8.9%. The detection limits were 6.3 and 7.2 pg/µL, respectively. The combined method was also able to identify two influenza A-associated genes (the HA and NP genes of the novel H1N1 influenza). CE separation was achieved with a sieving matrix of 1% poly(vinylpyrrolidone) (Mr=1,300,000) in 1× TBE buffer (pH 8.45). The combined Palm PCR-portable CE system should provide an improved, fast on-site molecular genetic diagnostic method.

In-cell protease assay systems based on trans-localizing molecular beacon proteins using HCV protease as a model system.

This study describes a sensitive in-cell protease detection system that enables direct fluorescence detection of a target protease and its inhibition inside living cells. This live-cell imaging system provides a fluorescent molecular beacon protein comprised of an intracellular translocation signal sequence, a protease-specific cleavage sequence, and a fluorescent tag sequence(s). The molecular beacon protein is designed to change its intracellular localization upon cleavage by a target protease, i.e., from the cytosol to a subcellular organelle or from a subcellular organelle to the cytosol. Protease activity can be monitored at the single cell level, and accordingly the entire cell population expressing the protease can be accurately enumerated. The clear cellular change in fluorescence pattern makes this system an ideal tool for various life science and drug discovery research, including high throughput and high content screening applications.