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1.
Foods ; 13(10)2024 May 16.
Article in English | MEDLINE | ID: mdl-38790847

ABSTRACT

In this study, we investigated the anti-hypertensive properties of mulberry products by modulating the renin-angiotensin system (RAS). Comparative analysis showed that the ethyl acetate fractions, particularly from the Cheongil and Daeshim cultivars, contained the highest levels of polyphenols and flavonoids, with concentrations reaching 110 mg gallic acid equivalent (GE)/g and 471 mg catechin equivalent (CE)/g of extract, respectively. The ethyl acetate fraction showed superior angiotensin-converting enzyme (ACE) inhibitory activity, mainly because of the presence of the prenylated flavonoids kuwanon G and H. UPLC/Q-TOF-MS analysis identified kuwanon G and H as the primary active components, which significantly contributed to the pharmacological efficacy of the extract. In vivo testing of mice fed a high-salt diet showed that the ethyl acetate fraction substantially reduced the heart weight and lowered the serum renin and angiotensinogen levels by 34% and 25%, respectively, highlighting its potential to modulate the RAS. These results suggested that the ethyl acetate fraction of mulberry root bark is a promising candidate for the development of natural ACE inhibitors. This finding has significant implications for the management of hypertension through RAS regulation and the promotion of cardiovascular health in the functional food industry.

2.
Int J Mol Sci ; 25(7)2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38612767

ABSTRACT

Diseases that occur in silkworms include soft rot, hardening disease, digestive diseases, and sepsis. However, research on the causes of bacterial diseases occurring in silkworms and the resulting changes in the microbial community is lacking. Therefore, we examined the morphological characteristics of sepsis and changes in the microbial community between silkworms that exhibit a unique odor and healthy silkworms; thus, we established a relationship between disease-causing microorganisms and sepsis. After producing a 16S rRNA amplicon library for samples showing sepsis, we obtained information on the microbial community present in silkworms using next-generation sequencing. Compared to that in healthy silkworms, in silkworms with sepsis, the abundance of the Firmicutes phylum was significantly reduced, while that of Proteobacteria was increased. Serratia sp. was dominant in silkworms with sepsis. After bacterial isolation, identification, and reinfection through the oral cavity, we confirmed this organism as the disease-causing agent; its mortality rate was 1.8 times higher than that caused by Serratia marcescens. In summary, we identified a new causative bacterium of silkworm sepsis through microbial community analysis and confirmed that the microbial community balance was disrupted by the aberrant proliferation of certain bacteria.


Subject(s)
Bombyx , Microbiota , Sepsis , Animals , Serratia/genetics , RNA, Ribosomal, 16S/genetics
3.
ACS Appl Mater Interfaces ; 15(51): 59939-59945, 2023 Dec 27.
Article in English | MEDLINE | ID: mdl-38087433

ABSTRACT

Electrochemical torsional artificial muscles have the potential to replace electric motors in the field of miniaturization. In particular, carbon nanotubes (CNTs) are some of the best materials for electrochemical torsional artificial muscles due to their remarkable mechanical strength and high electrical conductivity. However, previous studies on CNT torsional muscle utilize only half of the whole potential range for torsional actuation because the actuations in the positive and negative voltage ranges offset each other. Here, we used an ion-exchange polymer, poly(sodium 4-styrenesulfonate) (PSS), which leads to the participation of only positive ions in the actuation of CNT muscles so that the whole potential range can be used for torsional actuation. As a result, PSS-coated CNT muscle can provide 1.9 times higher torsional actuation compared to neat CNT torsional muscle. This PSS-coated CNT muscle not only provides high performance but also facilitates a one-body system for electrochemical torsional actuation. From these advantages, we implement a one-body torsional muscle for the realization of the forward motion of a model boat. This high performance and one-body structure for electrochemical torsional muscles can be used for further applications, such as soft robotics and implantable devices.

4.
Mar Pollut Bull ; 196: 115569, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37922593

ABSTRACT

Prokaryotes play an important role in marine nitrogen and methane cycles. However, their community changes and metabolic modifications to the concurrent impact of ocean warming (OW), acidification (OA), deoxygenation (OD), and anthropogenic­nitrogen-deposition (AND) from the surface to the deep ocean remains unknown. We examined here the amplicon sequencing approach across the surface (0-200 m; SL), intermediate (200-1000 m; IL), and deep layers (1000-2200 m; DL), and characterized the simultaneous impacts of OW, OA, OD, and AND on the Western North Pacific Ocean prokaryotic changes and their functional pattern in nitrogen and methane cycles. Results showed that SL possesses higher ammonium oxidation community/metabolic composition assumably the reason for excess nitrogen input from AND and modification of their kinetic properties to OW adaptation. Expanding OD at IL showed hypoxic conditions in the oxygen minimum layer, inducing higher microbial respiration that elevates the dimerization of nitrification genes for higher nitrous oxide production. The aerobic methane-oxidation composition was dominant in SL presumably the reason for adjustment in prokaryotic optimal temperature to OW, while anaerobic oxidation composition was dominant at IL due to the evolutionary changes coupling with higher nitrification. Our findings refocus on climate-change impacts on the open ocean ecosystem from the surface to the deep-environment integrating climate-drivers as key factors for higher nitrous-oxide and methane emissions.


Subject(s)
Ecosystem , Seawater , Pacific Ocean , Methane , Nitrogen
5.
J Insect Sci ; 23(5)2023 Sep 01.
Article in English | MEDLINE | ID: mdl-37804503

ABSTRACT

The domesticated silkworm, Bombyx mori Linnaeus (Lepidoptera: Bombycidae), often poses a challenge in strain identification due to similarities in morphology and genetic background. In South Korea, around 40 silkworm strains are classified as premium, including 5 endemic tri-molting strains: Goryeosammyeon, Sammyeonhonghoeback, Hansammyeon, Sun7ho, and Sandongsammyeon. These strains have potential for breeding programs in response to emerging industry demands, necessitating a reliable strain identification method. In this study, we established a molecular diagnosis approach for these 5 strains. We selected 2-4 single-nucleotide polymorphisms (SNPs) for each strain from whole-genome sequences of 39 strains, encompassing 37 previously studied and 2 newly added. These SNPs were utilized to construct decision trees for each endemic strain identification. The SNPs can be used to distinguish each target strain from the 38 nontarget strains by the tetra-primer amplification refractory mutation system-polymerase chain reaction, with the exception of HMS which needs the addition of PCR-restriction fragment length polymorphism method at the final step. This decision tree-based method using genomic SNPs, coupled with the 2 typing methods, produced consistent and accurate results, providing 100% accuracy. Additionally, the significant number of remaining SNPs identified in this study could be valuable for future diagnosis of the other strains.


Subject(s)
Bombyx , Polymorphism, Single Nucleotide , Animals , Bombyx/genetics , Chromosome Mapping , Polymerase Chain Reaction , Republic of Korea
6.
Small Methods ; 7(10): e2300526, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37317005

ABSTRACT

Owing to increasing amount of research on energy harvesting, studies on harvesters for practical application and their performance are attracting attention. Therefore, studies on the use of continuous energy as an energy source for energy-harvesting devices are being conducted, and fluid flows, e.g., wind, river flow, and sea wave, are widely used as input energy sources for continuous energy harvesting. A new energy-harvesting technology has emerged based on the mechanical stretch and release of coiled carbon nanotube (CNT) yarns, which generate energy based on the change in the electrochemical double-layer capacitance. First, this CNT yarn-based mechanical energy harvester is demonstrated, which is applicable to various environments where fluid flow exists. This environment-adaptable harvester uses rotational energy as the mechanical energy source and is tested in river and ocean environments. Moreover, an attachable-type harvester for the application of the existing rotational system is devised. In the case of a slow rotational environment, a square-wave strain-applying harvester has been implemented, which can convert sinusoidal strain motion into square-wave strain motion for high output voltages. To achieve high performance of practical harvesting applications, a scale-up method for powering signal-transmitting devices has been implemented.

7.
Orthop Surg ; 15(7): 1920-1925, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37254251

ABSTRACT

BACKGROUND: Treatments for chronic perilunate or lunate dislocations are very difficult and associated with poor prognoses. There is no established treatment method and are still many controversies. CASE PRESENTATION: We reported three cases of chronic neglected lunate volar dislocation treated with a novel surgical technique. All three cases were males with wrist pain and tingling sensation. Radiographs confirmed chronic volar dislocation of the lunate. Open reduction was performed by combined volar and dorsal approaches. After anatomical reduction, scapholunate and lunotriquetral interosseous ligament reconstructions were performed with the palmaris longus tendon and synthetic tape. The patients had an uneventful postoperative period with satisfactory functional outcomes at the last follow-up. CONCLUSIONS: We believe that open reduction and interosseous ligament reconstruction using the autogenous tendon and synthetic tape may be a valuable option for treating chronic volar dislocation of the lunate.


Subject(s)
Joint Dislocations , Lunate Bone , Scaphoid Bone , Wrist Injuries , Male , Humans , Female , Scaphoid Bone/surgery , Ligaments, Articular/surgery , Lunate Bone/diagnostic imaging , Lunate Bone/surgery , Joint Dislocations/diagnostic imaging , Joint Dislocations/surgery , Upper Extremity , Wrist Injuries/diagnostic imaging , Wrist Injuries/surgery
8.
Orthop Surg ; 15(1): 362-365, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36222208

ABSTRACT

BACKGROUND: Pyoderma gangrenosum (PG) is a reactive, noninfectious, neutrophilic dermatosis. Diagnosis of PG is based on exclusion, due to lack of availability of a confirmatory test. PG is not caused by infection or gangrene. Misdiagnosis or delayed diagnosis of PG can lead to devastating results. CASE PRESENTATION: In this report, we present a patient with a delayed diagnosis of PG lesion on right hand. Despite initial surgical treatment, the wound was aggravated, and amputation was considered; however, it was eventually treated successfully with an autologous split thickness skin graft. CONCLUSIONS: Knowledge of the PG is essential to actively consider PG in early stage to help facilitate immediate treatment and avoid unnecessary interventions that may worsen the outcome.


Subject(s)
Hand , Pyoderma Gangrenosum , Humans , Pyoderma Gangrenosum/diagnosis , Pyoderma Gangrenosum/surgery , Hand/pathology
9.
Int J Mol Sci ; 23(24)2022 Dec 18.
Article in English | MEDLINE | ID: mdl-36555784

ABSTRACT

Ribosomal protein S6 kinase 1 (S6K1), a key downstream effector of the mammalian target of rapamycin (mTOR), regulates diverse functions, such as cell proliferation, cell growth, and protein synthesis. Because S6K1 was previously known to be localized in the cytoplasm, its function has been mainly studied in the cytoplasm. However, the nuclear localization and function of S6K1 have recently been elucidated and other nuclear functions are expected to exist but remain elusive. Here, we show a novel nuclear role of S6K1 in regulating the expression of the Wnt target genes. Upon activation of the Wnt signaling, S6K1 translocated from the cytosol into the nucleus and subsequently bound to ß-catenin and the cofactors of the Wnt/ß-catenin transcriptional complex, leading to the upregulation of the Wnt target genes. The depletion or repression of S6K1 downregulated the Wnt target gene expression by inhibiting the formation of the Wnt/ß-catenin transcriptional complex. The S6K1-depleted colon cancer cell lines showed lower transcription levels of the Wnt/ß-catenin target genes and a decrease in the cell proliferation and invasion compared to the control cell lines. Taken together, these results indicate that nuclear S6K1 positively regulates the expression of the Wnt target genes by inducing the reciprocal interaction of the subunits of the transcriptional complex.


Subject(s)
Wnt Signaling Pathway , beta Catenin , Wnt Signaling Pathway/physiology , beta Catenin/genetics , beta Catenin/metabolism , Ribosomal Protein S6 Kinases/metabolism , Cell Nucleus/metabolism , Cell Line
10.
Int J Biol Macromol ; 213: 317-327, 2022 Jul 31.
Article in English | MEDLINE | ID: mdl-35605719

ABSTRACT

Chemically modified silk fibroin (SF) bioink has been used for three-dimensional (3D) bioprinting in tissue engineering because of its biocompatibility and printability. Also, fluorescent silk fibroin (FSF) from transgenic silkworms has been recently applied in biomedicine because of its fluorescence property. However, the fabrication of fluorescent hydrogel from FSF has not been elucidated. In this study, we showed the fabrication of a digital light processing (DLP) printable bioink from a chemically modified FSF. This bioink was fabricated by covalent conjugation of FSF and glycidyl methacrylate (GMA) and can be printed into various structures, such as the brain, ear, hand, lung, and internal organs. The physical properties of glycidyl methacrylated fluorescent silk fibroin (FSGMA) hydrogel was like the glycidyl methacrylated non-fluorescent silk fibroin (SGMA) hydrogel. The FSGMA hydrogel significantly retains its fluorescence property and has excellent biocompatibility. All these properties make FSGMA hydrogel a potent tool in encapsulated cell tracking and observing the scaffolds' degradation in vivo. This study suggested that our 3D DLP printable FSF bioink could play a promising role in the biomedical field.


Subject(s)
Bioprinting , Fibroins , Bioprinting/methods , Fibroins/chemistry , Hydrogels/chemistry , Printing, Three-Dimensional , Silk/chemistry , Tissue Engineering/methods , Tissue Scaffolds/chemistry
11.
Foods ; 11(7)2022 03 22.
Article in English | MEDLINE | ID: mdl-35406986

ABSTRACT

An analytical method was developed to simultaneously determine pyridate, quizalofop-ethyl, and cyhalofop-butyl in brown rice, soybean, potato, pepper, and mandarin using LC-MS/MS. Purification was optimized using various sorbents: primary−secondary amine, octadecyl (C18) silica gel, graphitized carbon black, zirconium dioxide-modified silica particles, zirconium dioxide-modified silica particles (Z-SEP), and multi-walled carbon nanotubes (MWCNTs). Three versions of QuECHERS methods were then tested using the optimal purification agent. Finally, samples were extracted using acetonitrile and QuEChERS EN salts and purified using the Z-SEP sorbent. A six-point matrix-matched external calibration curve was constructed for the analytes. Good linearity was achieved with a determination coefficient ≥0.999. The limits of detection and quantification were 0.0075 mg/kg and 0.01 mg/kg, respectively. The method was validated after fortifying the target standards to the blank matrices at three concentration levels with five replicates for each concentration. The average recovery was within an acceptable range (70−120%), with a relative standard deviation <20%. The applicability of the developed method was evaluated with real-world market samples, all of which tested negative for these three herbicide residues. Therefore, this method can be used for the routine analysis of pyridate, quizalofop-ethyl, and cyhalofop-butyl in agricultural products.

12.
Adv Mater ; 34(27): e2201826, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35475584

ABSTRACT

Stretching a coiled carbon nanotube (CNT) yarn can provide large, reversible electrochemical capacitance changes, which convert mechanical energy to electricity. Here, it is shown that the performance of these "twistron" harvesters can be increased by optimizing the alignment of precursor CNT forests, plastically stretching the precursor twisted yarn, applying much higher tensile loads during precoiling twist than for coiling, using electrothermal pulse annealing under tension, and incorporating reduced graphene oxide nanoplates. The peak output power for a 1 and a 30 Hz sinusoidal deformation are 0.73 and 3.19 kW kg-1 , respectively, which are 24- and 13-fold that of previous twistron harvesters at these respective frequencies. This performance at 30 Hz is over 12-fold that of other prior-art mechanical energy harvesters for frequencies between 0.1 and 600 Hz. The maximum energy conversion efficiency is 7.2-fold that for previous twistrons. Twistron anode and cathode yarn arrays are stretched 180° out-of-phase by locating them in the negative and positive compressibility directions of hinged wine-rack frames, thereby doubling the output voltage and reducing the input mechanical energy.

13.
Infect Chemother ; 54(4): 803-807, 2022 Dec.
Article in English | MEDLINE | ID: mdl-32869553

ABSTRACT

Cytomegalovirus (CMV) causes severe infection in immunocompromised patients, especially those with acquired immunodeficiency syndrome (AIDS), those who have undergone organ transplantation, and/or those who are being treated with steroids. In patients with AIDS, CMV is the most common pathogen that causes opportunistic infections. Here, we present a case of liver abscess due to CMV in a 58-year-old man diagnosed with AIDS. At the time of the study, his CD4 T lymphocyte count was 39 cells/mm3, and his human immunodeficiency virus (HIV) ribonucleic acid (RNA) level was 411,000 copies/mL. Upon presentation, he complained of upper abdominal pain. Ultrasonography-guided percutaneous drainage of the liver abscess was performed, and polymerase chain reaction analysis of the drained pus was positive for CMV. He was treated with intravenous ganciclovir, after which he recovered fully. In conclusion, our patient represents, to our knowledge, the first described case of liver abscess caused by CMV in an AIDS patient, which was probably facilitated by severe immunodeficiency.

14.
Angew Chem Int Ed Engl ; 60(19): 10563-10567, 2021 05 03.
Article in English | MEDLINE | ID: mdl-33565220

ABSTRACT

The carbon nanotube (CNT) yarn supercapacitor has high potential for in vivo energy storage because it can be used in aqueous environments and stitched to inner parts of the body, such as blood vessels. The biocompatibility issue for frequently used pseudocapacitive materials, such as metal oxides, is controversial in the human body. Here, we report an implantable CNT yarn supercapacitor inspired by the cellular redox system. In all living cells, nicotinamide adenine dinucleotide (NAD) is a key redox biomolecule responsible for cellular energy transduction to produce adenosine triphosphate (ATP). Based on this redox system, CNT yarn electrodes were fabricated by inserting a twist in CNT sheets with electrochemically deposited NAD and benzoquinone for redox shuttling. Consequently, the NAD/BQ/CNT yarn electrodes exhibited the maximum area capacitance (55.73 mF cm-2 ) under physiological conditions, such as phosphate-buffered saline and serum. In addition, the yarn electrodes showed a negligible loss of capacitance after 10 000 repeated charge/discharge cycles and deformation tests (bending/knotting). More importantly, NAD/BQ/CNT yarn electrodes implanted into the abdominal cavity of a rat's skin exhibited the stable in vivo electrical performance of a supercapacitor. Therefore, these findings demonstrate a redox biomolecule-applied platform for implantable energy storage devices.


Subject(s)
Biocompatible Materials/metabolism , Nanotubes, Carbon/chemistry , Skin/metabolism , Animals , Biocompatible Materials/chemistry , Oxidation-Reduction , Rats , Skin/cytology
15.
Science ; 371(6528): 494-498, 2021 01 29.
Article in English | MEDLINE | ID: mdl-33510023

ABSTRACT

Success in making artificial muscles that are faster and more powerful and that provide larger strokes would expand their applications. Electrochemical carbon nanotube yarn muscles are of special interest because of their relatively high energy conversion efficiencies. However, they are bipolar, meaning that they do not monotonically expand or contract over the available potential range. This limits muscle stroke and work capacity. Here, we describe unipolar stroke carbon nanotube yarn muscles in which muscle stroke changes between extreme potentials are additive and muscle stroke substantially increases with increasing potential scan rate. The normal decrease in stroke with increasing scan rate is overwhelmed by a notable increase in effective ion size. Enhanced muscle strokes, contractile work-per-cycle, contractile power densities, and energy conversion efficiencies are obtained for unipolar muscles.


Subject(s)
Artificial Organs , Muscle Contraction , Muscles , Nanotubes, Carbon
16.
Nat Commun ; 12(1): 535, 2021 01 22.
Article in English | MEDLINE | ID: mdl-33483493

ABSTRACT

Optogenetics is a powerful technique that allows target-specific spatiotemporal manipulation of neuronal activity for dissection of neural circuits and therapeutic interventions. Recent advances in wireless optogenetics technologies have enabled investigation of brain circuits in more natural conditions by releasing animals from tethered optical fibers. However, current wireless implants, which are largely based on battery-powered or battery-free designs, still limit the full potential of in vivo optogenetics in freely moving animals by requiring intermittent battery replacement or a special, bulky wireless power transfer system for continuous device operation, respectively. To address these limitations, here we present a wirelessly rechargeable, fully implantable, soft optoelectronic system that can be remotely and selectively controlled using a smartphone. Combining advantageous features of both battery-powered and battery-free designs, this device system enables seamless full implantation into animals, reliable ubiquitous operation, and intervention-free wireless charging, all of which are desired for chronic in vivo optogenetics. Successful demonstration of the unique capabilities of this device in freely behaving rats forecasts its broad and practical utilities in various neuroscience research and clinical applications.


Subject(s)
Electrodes, Implanted , Optogenetics/instrumentation , Optogenetics/methods , Wireless Technology , Animals , Brain/physiology , Deep Brain Stimulation/methods , Electromagnetic Phenomena , Humans , Locomotion/physiology , Male , Rats, Sprague-Dawley
17.
Biotechnol Prog ; 36(6): e3054, 2020 11.
Article in English | MEDLINE | ID: mdl-32706513

ABSTRACT

Genome editing by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associated protein (Cas)9, a third-generation gene scissors, and molecular breeding at the genome level are attracting considerable attention as future breeding techniques. In the present study, genetic and phenotypic analyses were conducted to examine the molecular breeding of Bombyx mori through CRISPR/Cas9-mediated editing of the kynurenine 3-monooxygenase (KMO) gene. The synthesized guide RNAs (gRNAs) were analyzed using T7 endonuclease I after introduction into the BM-N silkworm cell line. To edit the silkworm gene, K1P gRNA, and Cas9 complexes were microinjected into silkworm embryos. After microinjection, the hatching rate and the incidence of mutation were determined as 18.1% and 60%, respectively. Gene mutation was verified in the heterozygous G0 generation, but no phenotypic change was observed; however, certain embryos and moths produced through sib-mating had significant differences compared to the wild-type. In successive generations, a distinct phenotypic change was also observed by continuous mating. Thus, although there are limitations in the phenotypic expression in breeding through the induction of deletion mutations, as in the present study, the process is believed to yield successful results within a shorter period compared to traditional breeding and is safer than transgenic technology.


Subject(s)
Bombyx/genetics , DNA Shuffling/methods , Gene Editing/methods , Kynurenine 3-Monooxygenase/genetics , Animals , CRISPR-Cas Systems/genetics
18.
Molecules ; 25(14)2020 Jul 08.
Article in English | MEDLINE | ID: mdl-32650569

ABSTRACT

The pharmacological effects of BST204-a fermented ginseng extract-on several types of cancers have been reported. However, the effects of ginseng products or single ginsenosides against cancer stem cells are still poorly understood. In this study, we identified the anti-tumorigenic and anti-invasive activities of BST204 through the suppression of the cancer stem cell marker, CD133. The treatment of embryonic carcinoma cells with BST204 induced the expression of the tumor suppressor protein, p53, which decreased the expression of cell cycle regulatory proteins and downregulated the expression of CD133 and several stemness transcription factors. These changes resulted in both the inhibition of tumor cell proliferation and tumorigenesis. The knockdown of CD133 suggests that it has a role in tumorigenesis, but not in cancer cell proliferation or cell cycle arrest. Treatment with BST204 resulted in the reduced expression of the mesenchymal marker, N-cadherin, and the increased expression of the epithelial marker, E-cadherin, leading to the suppression of tumor cell migration and invasion. The knockdown of CD133 also exhibited an anti-invasive effect, indicating the role of CD133 in tumor invasion. The single ginsenosides Rg3 and Rh2-major components of BST204-exhibited limited effects against cancer stem cells compared to BST204, suggesting possible synergism among several ginsenoside compounds.


Subject(s)
Carcinogenesis , Carcinoma, Embryonal , Cell Movement/drug effects , Neoplastic Stem Cells , Plant Extracts/pharmacology , AC133 Antigen/biosynthesis , Carcinogenesis/drug effects , Carcinogenesis/metabolism , Carcinogenesis/pathology , Carcinoma, Embryonal/drug therapy , Carcinoma, Embryonal/metabolism , Carcinoma, Embryonal/pathology , Cell Line, Tumor , Gene Expression Regulation, Neoplastic/drug effects , Humans , Neoplastic Stem Cells/metabolism , Neoplastic Stem Cells/pathology , Tumor Suppressor Protein p53/biosynthesis
19.
Biosens Bioelectron ; 164: 112318, 2020 Sep 15.
Article in English | MEDLINE | ID: mdl-32479343

ABSTRACT

Various studies about harvesting energy for future energy production have been conducted. In particular, replacing batteries in implantable medical devices with electrical harvesting is a great challenge. Here, we have improved the electrical harvesting performance of twisted carbon nanotube yarn, which was previously reported to be an electrical energy harvester, by biscrolling positively charged ferritin protein in a biofluid environment. The harvester electrodes are made by biscrolling ferritin (40 wt%) in carbon nanotube yarn and twisting it into a coiled structure, which provides stretchability. The coiled ferritin/carbon nanotube yarn generated a 2.8-fold higher peak-to-peak open circuit voltage (OCV) and a 1.5-fold higher peak power than that generated by bare carbon nanotube yarn in phosphate-buffered saline (PBS) buffer. The improved performance is the result of the increased capacitance change and the shifting of the potential of zero charges that are induced by the electrochemically capacitive, positively charged ferritin. As a result, we confirm that the electrical performance of the carbon nanotube harvester can be improved using biomaterials. This carbon nanotube yarn harvester, which contains protein, has the potential to replace batteries in implantable devices.


Subject(s)
Biosensing Techniques , Nanotubes, Carbon , Electric Capacitance , Electricity , Ferritins
20.
Mar Pollut Bull ; 158: 111381, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32573454

ABSTRACT

We measured the concentrations of nutrients, fluorescent dissolved organic matter (FDOM), and photosynthetic pigments in seawater during the springs of 2018 and 2019 in Jinhae Bay, Korea. The samplings were carried out during the severe and weak outbreaks of paralytic shellfish poisoning (PSP) in April 2018 and March 2019, respectively. The additional sampling campaigns were carried out before and after the PSP outbreak for the comparison. During the severe PSP outbreak, lower salinities, higher organic and total nutrients, and higher humic-like FDOM were observed. Although the environmental condition of April 2018 is favorable for the growth of dinoflagellates, the lowest peridinin (dinoflagellate index) and highest fucoxanthin (diatom index) concentrations were observed amongst all sampling periods. Thus, our results suggest that PSP could be more effectively produced by dinoflagellates in the course of the ecological shift by interspecific competition under the environmental condition favorable for dinoflagellates.


Subject(s)
Dinoflagellida , Shellfish Poisoning , Bays , Disease Outbreaks , Humans , Nutrients , Republic of Korea
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