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1.
Front Vet Sci ; 10: 1287335, 2023.
Article in English | MEDLINE | ID: mdl-37937150

ABSTRACT

Long-term use of proton-pump inhibitors can induce fundic gland polyps in the human stomach. However, this phenomenon has not been described in the veterinary literature. A 5-year-old intact female Maltese dog was referred to our hospital with chronic intermittent vomiting. The dog had been administered omeprazole (0.7-1.0 mg/kg PO q24 h) for the management of hydrocephalus for over 4 years; the omeprazole dose was increased to 10 mg/kg PO q24 h 8 months prior to presentation at referring hospital. Abdominal ultrasonography revealed marked thickening of the gastric wall with multi-lobulated, thickened folds. Subsequent endoscopy revealed marked polypoid lesions, and histological examination of the biopsy samples was consistent with the fundic gland polyps associated with proton-pump inhibitor use in humans. The lesions resolved after cessation of omeprazole, as assessed by ultrasonography. This report describes a case of fundic gland polyps following the long-term administration of omeprazole in a dog.

2.
3D Print Addit Manuf ; 10(5): 917-929, 2023 Oct 01.
Article in English | MEDLINE | ID: mdl-37886417

ABSTRACT

Single-step 3D printing, which can manufacture complicated designs without assembly, has the potential to completely change our design perspective, and how 3D printing products, rather than printing static components, ready-to-use movable mechanisms become a reality. Existing 3D printing solutions are challenged by precision limitations, and cannot directly produce tightly mated moving surfaces. Therefore, joints must be designed with a sufficient gap between the components, resulting in joints and other mechanisms with imprecise motion. In this study, we propose a bio-inspired printable joint and apply it to a Single sTep 3D-printed Prosthetic hand (ST3P hand). We simulate the anatomical structure of the human finger joint and implement a cam effect that changed the distance between the contact surfaces through the elastic bending of the ligaments as the joint flexed. This bio-inspired design allows the joint to be single-step 3D printed and provides precise motion. The bio-inspired printable joint makes it possible for the ST3P hand to be designed as a lightweight (∼255 g), low-cost (∼$500) monolithic structure with nine finger joints and manufactured via single-step 3D printing. The ST3P hand takes ∼6 min to assemble, which is approximately one-tenth the assembly time of open-source 3D printed prostheses. The hand can perform basic hand tasks of activities of daily living by providing a pulling force of 48 N and grasp strength of 20 N. The simple manufacturing of the ST3P hand could help us take one step closer to realizing fully customized robotic prosthetic hands at low cost and effort.

4.
Cancer Res Treat ; 54(4): 1074-1080, 2022 Oct.
Article in English | MEDLINE | ID: mdl-34942684

ABSTRACT

PURPOSE: There is a potential risk that lobular carcinoma in situ (LCIS) on preoperative biopsy might be diagnosed as ductal carcinoma in situ (DCIS) or invasive carcinoma in the final pathology. This study aimed to evaluate the rate of upgrade of LCIS on preoperative biopsy to DCIS or invasive carcinoma. MATERIALS AND METHODS: Data of 55 patients with LCIS on preoperative biopsy were analyzed. All patients underwent surgery between 1991 and 2016 at Severance Hospital in Seoul, Korea. We analyzed the rate of upgrade of preoperative LCIS to DCIS or invasive cancer in the final pathology. The clinicopathologic features related to the upgrade were evaluated. RESULTS: The rate of upgrade of LCIS to DCIS or invasive carcinoma was 16.4% (9/55). In multivariate analysis, microcalcification and progesterone receptor expression were significantly associated with the upgrade of LCIS (p=0.023 and p=0.044, respectively). CONCLUSION: The current study showed a relatively high rate of upgrade of LCIS on preoperative biopsy to DCIS or invasive cancer. The presence of microcalcification and progesterone receptor expression may be potential predictors of upgradation of LCIS on preoperative biopsy. Surgical excision of the LCIS during preoperative biopsy could be a management option to identify the concealed malignancy.


Subject(s)
Breast Carcinoma In Situ , Breast Neoplasms , Calcinosis , Carcinoma in Situ , Carcinoma, Intraductal, Noninfiltrating , Carcinoma, Lobular , Biopsy , Breast Carcinoma In Situ/diagnosis , Breast Carcinoma In Situ/pathology , Breast Carcinoma In Situ/surgery , Breast Neoplasms/diagnosis , Breast Neoplasms/surgery , Calcinosis/diagnosis , Calcinosis/surgery , Carcinoma in Situ/pathology , Carcinoma, Intraductal, Noninfiltrating/diagnosis , Carcinoma, Intraductal, Noninfiltrating/pathology , Carcinoma, Intraductal, Noninfiltrating/surgery , Carcinoma, Lobular/diagnosis , Carcinoma, Lobular/pathology , Carcinoma, Lobular/surgery , Female , Humans , Receptors, Progesterone
5.
Ann Surg Treat Res ; 103(6): 313-322, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36601341

ABSTRACT

Purpose: Although adjuvant chemotherapy (CTx) is still recommended for high-risk patients with hormone receptor-positive and human epidermal receptor (HER)-2-negative breast cancer, recent studies found that selected patients with low disease burden may be spared from CTx and receive hormonal treatment (HT) alone. This study aims to evaluate the trends of treatment (CTx + HT vs. HT alone) in Korea and to assess the impact on overall survival (OS) according to treatment pattern. Methods: The Korean Breast Cancer Society Registry was queried (2000 to 2018) for women with pT1-2N0-1 hormone receptor-positive and HER2-negative disease who underwent surgery and adjuvant systemic treatment (CTx and HT). Clinicopathologic factors, change in pattern of treatment over time, and OS for each treatment option were analyzed. Results: A total of 40,938 women were included in the study; 20,880 (51.0%) received CTx + HT, while 20,058 (49.0%) received HT only. In recent years, there has been a steady increase in the use of HT alone, from 21.0% (2000) to 64.6% (2018). In Cox regression analysis, age, type of breast and axillary operations, T and N stages, body mass index, histologic grade, and presence of lymphovascular invasion were prognostic indicators for OS. There was no significant difference between CTx + HT and HT alone in terms of OS (P = 0.126). Conclusion: Over the years, there has been a shift from CTx + HT to HT alone without a significant difference in OS. Therefore, HT alone could be a safe treatment option in selected patients, even those with T2N1 disease.

6.
Clin Breast Cancer ; 21(6): e631-e637, 2021 12.
Article in English | MEDLINE | ID: mdl-34024752

ABSTRACT

BACKGROUND: The relationship between obesity and breast cancer stage is not well-known in the Korean population. This study aimed to identify the effect of body mass index (BMI) on initial breast cancer stage. PATIENTS AND METHODS: Among patients who underwent surgery for breast cancer (stages 0-III) from June 2003 to December 2018, we analyzed 4510 patients for whom there were BMI data. RESULTS: The average BMI of our patients was 23.5 (14.2-44.9). In total, 4.6% and 24.2% of the patients had a BMI of ≥30 and 25-29.9, respectively. In the patients with obesity, the proportion of T2 to T4 was 41.4%, which was higher than that in patients with a BMI of 25 to 29 (28.4%; P = .001) or a BMI of <25 (23.3%; P < .001). There was no difference in positive rates of estrogen receptor and progesterone receptor with BMI, but obese patients were less likely to be human epidermal growth factor receptor 2 positive. Patients with higher stages were more likely to have a higher BMI. The effect of BMI on stage was stronger in patients <50 years (odds ratio, 2.439; 95% CI, 1.783-3.335). Although there was no statistical significance, tumors >2 cm were less likely to be palpable in obese patients than in patients of normal weight (nonpalpable in 33.8% and 27.0%, respectively). CONCLUSION: Our study suggests that obesity is associated with a more advanced breast cancer stage, which represents a poor prognosis, and large tumors tend to be less palpable in women with obesity.


Subject(s)
Body Mass Index , Breast Neoplasms/epidemiology , Obesity/epidemiology , Adult , Age Factors , Breast Neoplasms/pathology , Comorbidity , Female , Humans , Middle Aged , Neoplasm Staging , Prognosis
7.
Sensors (Basel) ; 21(7)2021 Mar 29.
Article in English | MEDLINE | ID: mdl-33805456

ABSTRACT

Autofocus is an essential technique for airborne synthetic aperture radar (SAR) imaging to correct phase errors mainly due to unexpected motion error. There are several well-known conventional autofocus methods such as phase gradient autofocus (PGA) and minimum entropy (ME). Although these methods are still widely used for various SAR applications, each method has drawbacks such as limited bandwidth of estimation, low convergence rate, huge computation burden, etc. In this paper, feature preserving autofocus (FPA) algorithm is newly proposed. The algorithm is based on the minimization of the cost function containing a regularization term. The algorithm is designed for postprocessing purpose, which is different from the existing regularization-based algorithms such as sparsity-driven autofocus (SDA). This difference makes the proposed method far more straightforward and efficient than those existing algorithms. The experimental results show that the proposed algorithm achieves better performance, convergence, and robustness than the existing postprocessing autofocus algorithms.

8.
J Breast Cancer ; 24(2): 183-195, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33913274

ABSTRACT

PURPOSE: Nipple-sparing mastectomy (NSM) includes various techniques, including conventional or endoscopic mastectomies. Since the introduction of robot-assisted NSM (RANSM) in 2015, 2 main methods have been used: gasless and gas-inflated techniques. The aim of this study was to compare clinicopathologic characteristics, surgical outcomes, and postoperative complications between patients treated with gasless RANSM and those treated with gas-inflated RANSM. METHODS: We conducted a retrospective study of women who underwent gasless or gas-inflated RANSM with immediate breast reconstruction between November 2016 and May 2019. The indications for RANSM were early breast cancer, interstitial mastopathy, or BRCA1/2 mutation carriers. Clinicopathologic characteristics, surgical outcomes, and postoperative complications were analyzed. The severity of complications was graded using the Clavien-Dindo system. RESULTS: A total of 58 RANSM procedures were performed in 46 women: 15 cases of gasless RANSM and 43 cases of gas-inflated RANSM. The proportion of node-negative disease was higher in the gas-inflated group (97.1%) than in the gasless group (69.2%, p = 0.016). Adjuvant radiotherapy was administered in 30.6% of the cases in the gasless group and only 5% of the cases in the gas-inflated group. Other clinicopathological factors were not significantly different between the groups. Regarding surgical outcomes, the initial incision was 1 cm longer in the gasless group (5.17 ± 0.88 cm) than that in the gas-inflated group (4.20 ± 1.05 cm; p = 0.002). The final incision was also longer in the gasless group (5.17 ± 0.88 cm) than that in the gas-inflated group (4.57 ± 1.07 cm; p = 0.040). Operation time, complication rate, and complication grade were not significantly different between the 2 groups. CONCLUSION: In this study, there were no significant differences in surgical outcomes or postoperative complications between gasless and gas-inflated RANSM, except for a longer incision with the gasless technique. Both techniques are reasonable options for RANSM followed by immediate reconstruction.

9.
Sensors (Basel) ; 21(4)2021 Feb 20.
Article in English | MEDLINE | ID: mdl-33672454

ABSTRACT

Green tide, which is a serious water pollution problem, is caused by the complex relationships of various factors, such as flow rate, several water quality indicators, and weather. Because the existing methods are not suitable for identifying these relationships and making accurate predictions, a new system and algorithm is required to predict the green tide phenomenon and also minimize the related damage before the green tide occurs. For this purpose, we consider a new network model using smart sensor-based federated learning which is able to use distributed observation data with geologically separated local models. Moreover, we design an optimal scheduler which is beneficial to use real-time big data arrivals to make the overall network system efficient. The proposed scheduling algorithm is effective in terms of (1) data usage and (2) the performance of green tide occurrence prediction models. The advantages of the proposed algorithm is verified via data-intensive experiments with real water quality big-data.

10.
RSC Adv ; 11(60): 38152-38160, 2021 Nov 23.
Article in English | MEDLINE | ID: mdl-35498094

ABSTRACT

Macroscopic assemblies of carbon nanotubes (CNTs) usually have a poor alignment and a low packing density due to their hierarchical structure. To realize the inherent properties of CNTs at the macroscopic scale, the CNT assemblies should have a highly aligned and densified structure. Shear-aligning processes are commonly employed for this purpose. This work investigates how shear flows affect the rearrangement of CNT bundles in macroscopic assemblies. We propose that buckling behavior of CNT bundles in a shear flow causes the poor alignment of CNT bundles and a low packing density of CNT assemblies; the flow pattern and the magnitude of shear stress induced by the flow are key factors to regulate this buckling behavior. To obtain CNT assemblies with a high packing density, the CNTs should undergo a laminar flow that has a sufficiently low shear stress. Understanding the effect of shear flow on the structure of CNT bundles may guide improvement of fabrication strategies.

11.
Forensic Sci Int ; 317: 110531, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33161236

ABSTRACT

Evidence of dried blood is very valuable in forensic science. Since the discovery of luminescence with Luminol and dried blood spots (DBSs) in 1928, interest and research on blood have continued to date. One of the most important factor that DBSs have is genes. However, the current use of distilled water (DDW) to collect and extract blood samples has disadvantages related to DNA stability. Therefore, this study aimed to develop an extraction reagent that is most suitable for gene extraction from DBSs. Blood was collected from 45 healthy adult men and women in vacuum blood containers without coagulants or anticoagulants. The collected blood was dried in various settings to check the performance of the extraction reagent. Extraction with Tris-EDTA (TE) and phosphate-buffered saline (PBS) was found more suitable in terms of gene interference effects compared with DDW; their performance was also compared with those of the newly developed extraction reagents. Upon comparing the results of polymerase chain reaction for human genomic DNA samples using glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene as the target, the performance of the newly developed extraction reagents, modified TE and PBS, was found to be relatively good. To determine the optimal composition of the developed extraction reagents, 12 new extraction reagents were developed with different pH and sodium concentrations. Among them, the best results were found when the DNA was extracted using extraction reagent No. 3 with pH 8.0 and containing 1 M NaCl. Next, the four extraction reagents, DDW, TE, PBS, and No. 3 were compared under nine different temperature and humidity conditions. Similarly, under various environmental conditions, extraction reagent No. 3 performed better than other reagents. It is proposed that modified TE and PBS mixed extraction reagents are the most suitable for collecting and preserving crime site samples. The proposed composition for a DNA extraction reagent can contribute greatly to crime scene reconstruction.


Subject(s)
Blood Stains , DNA/isolation & purification , Indicators and Reagents , Specimen Handling/methods , DNA Fingerprinting , Electrophoresis, Agar Gel , Female , Forensic Medicine/methods , Humans , Hydrogen-Ion Concentration , Male , Polymerase Chain Reaction , Sodium Chloride
13.
J Breast Cancer ; 23(1): 107-112, 2020 02.
Article in English | MEDLINE | ID: mdl-32140275

ABSTRACT

Minimal invasive surgical technique has been increasingly applied to breast surgery. Since the first robot-assisted nipple-sparing mastectomy was introduced, we have been performing nipple-sparing mastectomy using multi-port robotic surgical system. Last year, the new robotic surgical system with single port was introduced. We report the development of a robotic nipple-sparing mastectomy with immediate reconstruction through a single incision using the updated single-port surgical robot system for a patient with ductal carcinoma in situ (DCIS). Breast reconstruction was performed using implants. Postoperative pathological examination revealed DCIS in both breasts. There were no major immediate complications, except for a minor skin burn on the right breast. Overall, the initial operation using the updated platform was safely performed.

14.
ACS Appl Mater Interfaces ; 12(11): 13107-13115, 2020 Mar 18.
Article in English | MEDLINE | ID: mdl-32078299

ABSTRACT

Carbon nanotube fibers (CNTFs) are directly spun from a floating-catalyst chemical vapor deposition apparatus using gas-phase carbon and an iron nanocatalyst. The essential synthesis and post-treatment factors that affect the strength of CNTFs are investigated to obtain CNTFs with greater strength than those of any previously reported high-performance fibers. The key factors optimized included the degree of rotational flow inside the reactor, the ratio of the starting materials, and the postsynthesis treatment conditions. The formation of rotational gas flow inside the reactor was confirmed by computational fluid dynamics simulations, and the feed ratio of the starting materials was optimized through response surface methodology. In addition, a reproducible and highly efficient postsynthesis treatment method was established. Pristine CNTFs with a high specific strength (SS) (average 2.2 N/tex, max. 2.3 N/tex) were synthesized through decreased rotational flow and optimization of the CNTF synthesis conditions. To improve the SS of the CNTFs further, we adopted an acid wet-stretching method that included washing and heat treatment. This drastically increased the SS of the CNTFs (average 5.5 N/tex, max. 6.4 N/tex) because of the decrease in the volume of the pores between the CNT bundles.

15.
IUCrJ ; 7(Pt 1): 90-99, 2020 Jan 01.
Article in English | MEDLINE | ID: mdl-31949908

ABSTRACT

MICAL is an oxidoreductase that participates in cytoskeleton reorganization via actin disassembly in the presence of NADPH. Although three MICALs (MICAL1, MICAL2 and MICAL3) have been identified in mammals, only the structure of mouse MICAL1 has been reported. Here, the first crystal structure of human MICAL3, which contains the flavin-containing monooxygenase (FMO) and calponin-homology (CH) domains, is reported. MICAL3 has an FAD/NADP-binding Rossmann-fold domain for mono-oxygenase activity like MICAL1. The FMO and CH domains of both MICAL3 and MICAL1 are highly similar in structure, but superimposition of the two structures shows a different relative position of the CH domain in the asymmetric unit. Based on kinetic analyses, the catalytic efficiency of MICAL3 dramatically increased on adding F-actin only when the CH domain was available. However, this did not occur when two residues, Glu213 and Arg530, were mutated in the FMO and CH domains, respectively. Overall, MICAL3 is structurally highly similar to MICAL1, which suggests that they may adopt the same catalytic mechanism, but the difference in the relative position of the CH domain produces a difference in F-actin substrate specificity.

16.
Front Oncol ; 10: 594388, 2020.
Article in English | MEDLINE | ID: mdl-33489893

ABSTRACT

PURPOSE: This study is to directly compare surgical outcomes between conventional nipple-sparing mastectomy (CNSM) and robot-assisted nipple-sparing mastectomy (RNSM). MATERIALS AND METHOD: For this case-control study, 369 cases of 333 patients who underwent CNSM or RNSM with immediate reconstruction between November 2016 and January 2019 at Severance Hospital in Seoul, Republic of Korea were reviewed. Patients with stage IV breast cancer (n = 1), receiving neoadjuvant chemotherapy (n = 43), or subjected to previous operations (n = 14) or radiotherapy on the breasts were excluded. The main outcomes were comparing rates of post-operative complications, of high-grade post-operative complications as defined by the Clavien-Dindo classification, and nipple necrosis between the CNSM and the RNSM groups. RESULTS: A total of 311 cases, including 270 CNSMs and 41 RNSMs, were analyzed. The rates of post-operative nipple necrosis (p = 0.026, 2.4 vs. 15.2%) and of high-grade post-operative complications (p = 0.031, 34.8 vs. 17.1%) in the RNSM group were significantly lower than those in the CNSM group. CONCLUSION: RNSM was associated with lower rates of high-grade post-operative complications and nipple necrosis than CNSM for patients with small breast volumes and less ptotic breasts.

17.
Asian J Surg ; 43(7): 735-741, 2020 Jul.
Article in English | MEDLINE | ID: mdl-31669037

ABSTRACT

BACKGROUND: Pseudoangiomatous stromal hyperplasia (PASH) is a benign mesenchymal proliferative lesion of the breast. Owing to the rarity of PASH, the pathogenesis, clinical manifestation, and optimal treatment of this condition remain unclear. We aimed to clarify the appropriate management of PASH. METHODS: We performed a retrospective analysis of the clinicopathological data of 66 cases with a diagnosis of PASH, confirmed by core needle biopsy (CNB) or surgical excision at Severance Hospital between 2000 and 2016. The primary endpoint was pathologic results after surgical excision of the lesion that confirmed PASH by CNB. The secondary endpoint was progression after the first treatment. RESULT: The median age of patients was 41 years (range, 14-61 years). Findings on medical imaging were nonspecific. CNB was performed in 61 cases, with a diagnosis of PASH confirmed in 39 cases (63.9%). No malignant or premalignant cells directly arising from PASH were identified after surgical excision that confirmed PASH via CNB. The progression rate after the first treatment was 16.6%, with lesion size, enlargement of palpable mass size, and a diagnosis other than PASH on CNB being factors associated with progression. CONCLUSION: CNB is sufficient to confirm PASH what is necessary for an abnormal imaging or suspicious physical examination finding. Surgical excision is not necessarily indicated to rule out occult malignancy after a diagnosis of PASH. Close monitoring or surgical excision are required to manage large lesions (>3 cm) or progressive growth of a PASH lesion.


Subject(s)
Angiomatosis/pathology , Angiomatosis/surgery , Biopsy, Large-Core Needle , Breast Diseases/pathology , Breast Diseases/surgery , Hyperplasia/pathology , Hyperplasia/surgery , Adolescent , Adult , Angiomatosis/diagnosis , Breast , Breast Diseases/diagnosis , Breast Diseases/diagnostic imaging , Disease Progression , Female , Follow-Up Studies , Humans , Hyperplasia/diagnosis , Magnetic Resonance Imaging , Middle Aged , Monitoring, Physiologic , Young Adult
18.
Yonsei Med J ; 60(11): 1028-1035, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31637884

ABSTRACT

PURPOSE: To validate and update a nomogram for predicting ductal carcinoma in situ (DCIS) upstaging in preoperative biopsy. MATERIALS AND METHODS: Medical records of 444 preoperative DCIS patients were evaluated and used to validate a previous version of the Severance nomogram for predicting DCIS upstaging in preoperative biopsy. Patients were divided into two groups according to the final postoperative pathology. Univariate and multivariate analyses with the chi-square test, Student's t-test, and binary logistic regression method identified new significant variables. The updated nomogram was evaluated with the C-index and Hosmer-Lemeshow goodness of fit test. RESULTS: The area under a receiver operating characteristic curve for comparison with the previous nomogram was 0.48. In postoperative pathology, the pure DCIS and invasive cancer groups comprised 345 and 99 cases, respectively. Approximately 22.3% of patients preoperatively diagnosed with DCIS were upstaged to invasive cancer. Significant variables in the univariate analysis were operation type, human epidermal growth factor receptor 2 overexpression, comedo necrosis, sonographic mass, mammographic mass, preoperative biopsy method, and suspicious microinvasion in preoperative biopsy. In multivariate analysis, operation type, sonographic mass, mammographic mass, and suspicious microinvasion were risk factors for upstaging. The updated model with these variables showed moderate discrimination and was appropriate in the calibration test. CONCLUSION: The previous nomogram did not effectively discriminate upstaging of preoperative DCIS in an independent cohort. An updated version of the nomogram appears to provide more accurate information for predicting preoperative DCIS upstaging.


Subject(s)
Breast Neoplasms/pathology , Breast Neoplasms/surgery , Carcinoma, Ductal, Breast/pathology , Carcinoma, Ductal, Breast/surgery , Nomograms , Adult , Aged , Biopsy , Female , Humans , Logistic Models , Middle Aged , Multivariate Analysis , Neoplasm Invasiveness , Neoplasm Staging , ROC Curve , Reproducibility of Results
19.
Soft Robot ; 6(2): 214-227, 2019 04.
Article in English | MEDLINE | ID: mdl-30566026

ABSTRACT

This article presents Exo-Glove Poly (EGP) II, a soft wearable robot for the hand with a glove that is completely constructed of polymer materials and that operates through tendon-driven actuation for use in spinal cord injury (SCI). EGP II can restore the ability to pinch and grasp any object for people with SCI in daily life. The design of the glove allows it to be compact and extends the range of hand sizes that can fit. A passive thumb structure was developed to oppose the thumb for improved grasping. To increase the robustness of the glove, EGP II was designed to have a minimal number of components using a single material. A kinematic model of the system was used to optimize the design parameters of an antagonistic tendon routing system on a single actuator for various hand sizes and repeated actuations. Experiments were conducted on two subjects with SCI to verify the grasping performance of EGP II. EGP II has a compact glove and an actuation system that can be placed on a desk or wheelchair, with the weights of 104 g and 1.14 kg, respectively.


Subject(s)
Hand/physiology , Polymers/chemistry , Robotics/instrumentation , Tendons/physiology , Activities of Daily Living , Equipment Design/instrumentation , Exoskeleton Device , Gloves, Protective , Hand Strength/physiology , Humans , Spinal Cord Injuries/physiopathology , Wearable Electronic Devices
20.
Materials (Basel) ; 11(11)2018 Nov 02.
Article in English | MEDLINE | ID: mdl-30400179

ABSTRACT

To increase the strength of carbon nanotube (CNT) fibers (CNTFs), the mean size of voids between bundles of CNTs was reduced by wet-pressing, and the CNTs were cross-linked. Separate and simultaneous physical (roller pressing) and chemical methods (cross-linking) were tested to confirm each method's effects on the CNTF strength. By reducing the fraction of pores, roller pressing decreased the cross-sectional area from 160 µm² to 66 µm² and increased the average load-at-break from 2.83 ± 0.25 cN to 4.41 ± 0.16 cN. Simultaneous injection of crosslinker and roller pressing augmented the cross-linking effect by increasing the infiltration of the crosslinker solution into the CNTF, so the specific strength increased from 0.40 ± 0.05 N/tex to 0.67 ± 0.04 N/tex. To increase the strength by cross-linking, it was necessary that the size of the pores inside the CNTF were reduced, and the infiltration of the solution was increased. These results suggest that combined physical and chemical treatment is effective to increase the strength of CNTFs.

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