Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
Más filtros

Banco de datos
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Sensors (Basel) ; 18(9)2018 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-30213111

RESUMEN

TVs and monitors are among the most widely used displays in various environments. However, they have limitations in their physical display conditions, such as a fixed size/position and a rigid/flat space. In this paper, we suggest a new "Display in the Wild" (DIW) concept to overcome the aforementioned problems. Our proposed DIW system allows us to display a flexibly large screen on dynamic non-planar surfaces at an arbitrary display position. To implement our DIW concept practically, we choose a projector as the hardware configuration in order to generate a screen anywhere with different sizes. However, distortion occurs when the projector displays content on a surface that is dynamic and/or non-planar. Therefore, we propose a distortion correction method for DIW to overcome the aforementioned surface constraints. Since projectors are not capture devices, we propose using a depth camera to determine the distortions on the surfaces quickly. We also propose DIW-specific calibration and fast/precise correction methods. Our calibration method is constructed to detect the projection surface easily and quickly, and also allows our proposed system to accommodate the intrinsic parameters such as a display resolution and field of view. We accomplish a fast undistortion process of the projector by considering only surface boundary pixels, which enables our method to run in real time. In our comprehensive experiments, the proposed DIW system generates undistorted screens such as TVs and monitors on dynamic non-planar surfaces at an arbitrary display position with Unmanned Aerial Vehicles (UAVs) in a fast and accurate manner, demonstrating its usefulness in practical DIW scenarios.

2.
Knee Surg Sports Traumatol Arthrosc ; 25(7): 2073-2080, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27904936

RESUMEN

PURPOSE: The purpose of this study was to analyse the natural course of symptomatic full-thickness and partial-thickness rotator cuff tears treated non-operatively and to identify risk factors affecting tear enlargement. METHODS: One hundred and twenty-two patients who received non-surgical treatment for a partial- or full-thickness supraspinatus tear were included in this study. All rotator cuff tears were diagnosed with magnetic resonance imaging (MRI), and the same modality was used for follow-up studies. Follow-up MRI was performed after at least a 6-month interval. We evaluated the correlation between tear enlargement and follow-up duration. Eleven risk factors were analysed by both univariate and multivariate analyses to identify factors that affect enlargement of rotator cuff tears. The mean follow-up period was 24.4 ± 19.5 months. RESULTS: Out of 122 patients, 34 (27.9%) patients had an initial full-thickness tear and 88 (72.1%) patients had a partial-thickness tear. Considering all patients together, tear size increased in 51/122 (41.8%) patients, was unchanged in 65/122 (53.3%) patients, and decreased in 6/122 (4.9%) patients. Tear size increased for 28/34 (82.4%) patients with full-thickness tears and 23/88 (26.1%) patients with partial-thickness tears. From the two groups which were followed over 12 months, a higher rate of enlargement was observed in full-thickness tears than in partial-thickness tears (6-12 months, n.s.; 12-24 months, P = 0.002; over 24 months, P < 0.001). Logistic regression revealed that having a full-thickness tear was the most reliable risk factor for tear progression (P < 0.001). CONCLUSIONS: This study found that 28/34 (82.4%) of symptomatic full-thickness rotator cuff tears and 23/88 (26.1%) of symptomatic partial-thickness tears increased in size over a follow-up period of 6-100 months. Full-thickness tears showed a higher rate of enlargement than partial-thickness tears regardless of the follow-up duration. Univariate and multivariate analyses suggested that full-thickness tear was the most reliable risk factor for tear enlargement. The clinical relevance of these observations is that full-thickness rotator cuff tears treated conservatively should be monitored more carefully for progression than partial-thickness tears. LEVEL OF EVIDENCE: IV.


Asunto(s)
Lesiones del Manguito de los Rotadores/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Puntaje de Gravedad del Traumatismo , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Traumatismos Ocupacionales/diagnóstico por imagen , Traumatismos Ocupacionales/patología , Factores de Riesgo , Lesiones del Manguito de los Rotadores/patología , Rotura/diagnóstico por imagen , Rotura/patología , Factores de Tiempo
3.
Arthroscopy ; 31(11): 2191-8, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26188786

RESUMEN

PURPOSE: To compare the clinical outcomes of arthroscopic in situ repair with the tear completion repair technique for partial-thickness rotator cuff tears (PT-RCTs). METHODS: We prospectively enrolled 100 cases with articular-sided and bursal-sided PT-RCTs exceeding 50% of tendon thickness and allocated them randomly. An in situ repair was performed in group 1 (n = 50). Completion of the remaining cuff tissue and repair were performed in group 2 (n = 50). The medial row was knotted as transosseous repair (suture-bridge technique) in all cases. American Shoulder Elbow Society (ASES) score, Constant shoulder (CS) score, Simple shoulder (SS) score, and Korean shoulder (KS) score, and visual analog scale (VAS) for pain and range of motion were assessed at 3, 6, and 12 months and at the last visit. Repaired tendon integrity was determined at 6 to 12 months by magnetic resonance imaging. RESULTS: Eight cases were lost to follow-up. Ultimately, 92 cases were analyzed. The average follow-up was 19.1 months (range, 12 to 42 months). Significant improvements in the VAS for pain and functional outcomes were observed in both groups postoperatively (P = .001 for VAS; P < .001 for ASES score; P < .001 for CS score; P = .001 for SS score; P<.001 for KS score). No significant difference in the clinical results was observed at any time between the groups. No difference of retear rate on articular-sided PT-RCT was observed between the groups (P = .34). Retears on the bursal-sided PT-RCT were more frequent in group 2 (P = .02). CONCLUSIONS: Arthroscopic repair of PT-RCT exceeding 50% of the thickness provided functional improvements and pain relief regardless of the repair technique. The retear rate for bursal-sided PT-RCT was higher in group 2, although the retear rate for the articular-sided PT-RCT was not different. LEVEL OF EVIDENCE: Level II, prospective comparative study.


Asunto(s)
Artroscopía/métodos , Manguito de los Rotadores/cirugía , Articulación del Hombro/cirugía , Traumatismos de los Tendones/cirugía , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Estudios Prospectivos , Rango del Movimiento Articular , Lesiones del Manguito de los Rotadores , Rotura , Lesiones del Hombro , Articulación del Hombro/fisiopatología , Técnicas de Sutura , Traumatismos de los Tendones/diagnóstico , Resultado del Tratamiento
4.
J Shoulder Elbow Surg ; 24(11): 1801-8, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26119631

RESUMEN

BACKGROUND: Subacromial impingement is a common cause of shoulder pain and one cause of rotator cuff disease. We aimed to identify which shoulder motions cause subacromial impingement by measuring the vertical displacement and peak strain of the coracoacromial ligament using ultrasound speckle tracking imaging. METHODS: Sixteen shoulders without shoulder disability were enrolled. All subjects were men, and the average age was 28.6 years. The vertical displacement and peak strain of the coracoacromial ligament were analyzed by the motion tracing program during the following active assisted motions (active motion controlled by the examiner): (1) forward flexion in the scapular plane, (2) horizontal abduction in the axial plane, (3) external rotation with the arm at 0° abduction (ER0), (4) internal rotation with the arm at 0° abduction (IR0), (5) internal rotation with the arm at 90° abduction (IR90), and (6) internal rotation at the back (IRB). RESULTS: The mean vertical displacement of the coracoacromial ligament during forward flexion (2.2 mm), horizontal abduction (2.2 mm), and IR90 (2.4 mm) was significantly greater than that during the other motions (ER0, -0.7 mm; IR0, 0.5 mm; IRB, 1.0 mm; P < .003). The mean peak strain was significantly higher in forward flexion (6.88%), horizontal abduction (6.58%), and IR90 (4.88%) than with the other motions (ER0, 1.42%; IR0, 1.78%; IRB, 2.61%; P < .003). CONCLUSIONS: Forward flexion, horizontal abduction, and IR90 showed higher vertical displacement and peak strain of the coracoacromial ligament, causing subacromial impingement. It is recommended that patients with impingement syndrome or a repaired rotator cuff avoid these shoulder motions.


Asunto(s)
Ligamentos Articulares/diagnóstico por imagen , Rango del Movimiento Articular/fisiología , Síndrome de Abducción Dolorosa del Hombro/diagnóstico por imagen , Estrés Mecánico , Adulto , Humanos , Ligamentos Articulares/fisiología , Masculino , Rotación , Hombro , Síndrome de Abducción Dolorosa del Hombro/fisiopatología , Articulación del Hombro/diagnóstico por imagen , Articulación del Hombro/fisiopatología , Ultrasonografía
5.
J Biol Chem ; 288(13): 9468-81, 2013 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-23344960

RESUMEN

The removal of initiating primers from the 5'-ends of each Okazaki fragment, required for the generation of contiguous daughter strands, can be catalyzed by the combined action of DNA polymerase δ and Fen1. When the flaps generated by displacement of DNA synthesis activity of polymerase δ become long enough to bind replication protein A or form hairpin structures, the helicase/endonuclease enzyme, Dna2, becomes critical because of its ability to remove replication protein A-coated or secondary structure flaps. In this study, we show that the N-terminal 45-kDa domain of Dna2 binds hairpin structures, allowing the enzyme to target secondary structure flap DNA. We found that this activity was essential for the efficient removal of hairpin flaps by the endonuclease activity of Dna2 with the aid of its helicase activity. Thus, the efficient removal of hairpin structure flaps requires the coordinated action of all three functional domains of Dna2. We also found that deletion of the N-terminal 45-kDa domain of Dna2 led to a partial loss of the intra-S-phase checkpoint function and an increased rate of homologous recombination in yeast. We discuss the potential roles of the N-terminal domain of Dna2 in the maintenance of genomic stability.


Asunto(s)
ADN Helicasas/genética , ADN Helicasas/metabolismo , ADN/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Roturas del ADN de Doble Cadena , ADN Helicasas/química , Desoxirribonucleasas/química , Marcadores Genéticos , Genoma , Conformación de Ácido Nucleico , Oligonucleótidos/genética , Unión Proteica , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Recombinación Genética , Fase S
6.
J Microbiol ; 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-38995433

RESUMEN

DNA double-strand break (DSB) repair is a fundamental cellular process crucial for maintaining genome stability, with homologous recombination and non-homologous end joining as the primary mechanisms, and various alternative pathways such as single-strand annealing (SSA) and microhomology-mediated end joining also playing significant roles under specific conditions. IRC genes were previously identified as part of a group of genes associated with increased levels of Rad52 foci in Saccharomyces cerevisiae. In this study, we investigated the effects of IRC gene mutations on DSB repair, focusing on uncharacterized IRC10, 19, 21, 22, 23, and 24. Gene conversion (GC) assay revealed that irc10Δ, 22Δ, 23Δ, and 24Δ mutants displayed modest increases in GC frequencies, while irc19Δ and irc21Δ mutants exhibited significant reductions. Further investigation revealed that deletion mutations in URA3 were not generated in irc19Δ mutant cells following HO-induced DSBs. Additionally, irc19Δ significantly reduced frequency of SSA, and a synergistic interaction between irc19Δ and rad52Δ was observed in DSB repair via SSA. Assays to determine the choice of DSB repair pathways indicated that Irc19 is necessary for generating both GC and deletion products. Overall, these results suggest a potential role of Irc19 in DSB repair pathways, particularly in end resection process.

7.
Clin Orthop Relat Res ; 471(3): 1021-7, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23096935

RESUMEN

BACKGROUND: Many surgeons perform a varus femoral or Salter pelvic osteotomy in patients with Legg-Calvé-Perthes (LCP) disease. However, more severely deformed femoral heads show greater congruency in adduction rather than in abduction. Therefore, a valgus-(flexion) femoral osteotomy (VFO) seems preferable rather than a varus femoral or Salter pelvic osteotomy. QUESTIONS/PURPOSES: We evaluated whether the VFO improves (1) femoral head roundness, (2) radiographic parameters reflecting hip subluxation, and (3) function. METHODS: We treated 25 patients (25 hips; 18 lateral pillar C and seven B) in the late fragmentation stage by VFO. Seven patients had additional pelvic procedures. VFO was performed at a mean age of 9.8 years. Three hips were Stulberg Class II, 20 were Class III, and two were Class IV. The following components of femoral head roundness were calculated from preoperative MRI and final radiographs: lateral and medial head roundness (LHR and MHR); anterior and posterior head roundness (AHR and PHR); central head height; and the ratios MHR/LHR and PHR/AHR. Continuity of Shenton's line, medial gap ratio were evaluated. Function was determined with the Iowa hip score. Minimum followup was 3.1 years (mean, 6.3 years; range, 3.1-11.2 years). RESULTS: All femoral head roundness measurements improved, with greatest improvement in the lateral and anterior head. Pillar C hips showed greater relative improvement than pillar B hips. The continuity of Shenton's line improved and the mean medial gap ratio decreased. Mean Iowa hip score improved from 71 before surgery to 90 at the last followup. CONCLUSIONS: VFO appears to help the deformed femoral head in the fragmentation stage to remodel to fit the acetabulum. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.


Asunto(s)
Cabeza Femoral/cirugía , Articulación de la Cadera/cirugía , Enfermedad de Legg-Calve-Perthes/cirugía , Osteotomía/métodos , Adolescente , Fenómenos Biomecánicos , Niño , Preescolar , Femenino , Cabeza Femoral/diagnóstico por imagen , Cabeza Femoral/fisiopatología , Articulación de la Cadera/diagnóstico por imagen , Articulación de la Cadera/fisiopatología , Humanos , Enfermedad de Legg-Calve-Perthes/diagnóstico por imagen , Enfermedad de Legg-Calve-Perthes/fisiopatología , Imagen por Resonancia Magnética , Masculino , Radiografía , Recuperación de la Función , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Factores de Tiempo , Resultado del Tratamiento
8.
Biochem Biophys Res Commun ; 427(3): 623-8, 2012 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-23026052

RESUMEN

RecQ helicases are well conserved proteins from bacteria to human and function in various DNA metabolism for maintenance of genome stability. Five RecQ helicases are found in humans, whereas only one RecQ helicase has been described in lower eukaryotes. However, recent studies predicted the presence of a second RecQ helicase, Hrq1, in fungal genomes and verified it as a functional gene in fission yeast. Here we show that 3'-5' helicase activity is intrinsically associated with Hrq1 of Saccharomyces cerevisiae. We also determined several biochemical properties of Hrq1 helicase distinguishable from those of other RecQ helicase members. Hrq1 is able to unwind relatively long duplex DNA up to 120-bp and is significantly stimulated by a preexisting fork structure. Further, the most striking feature of Hrq1 is its absolute requirement for a long 3'-tail (⩾70-nt) for efficient unwinding of duplex DNA. We also found that Hrq1 has potent DNA strand annealing activity. Our results indicate that Hrq1 has vigorous helicase activity that deserves further characterization to expand our understanding of RecQ helicases.


Asunto(s)
ADN de Cadena Simple/química , RecQ Helicasas/química , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/enzimología , Conformación de Ácido Nucleico , RecQ Helicasas/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Especificidad por Sustrato
9.
Nucleic Acids Res ; 38(5): 1583-95, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20007605

RESUMEN

The non-essential VTS1 gene of Saccharomyces cerevisiae is highly conserved in eukaryotes and encodes a sequence- and structure-specific RNA-binding protein. The Vts1 protein has been implicated in post-transcriptional regulation of a specific set of mRNAs that contains its-binding site at their 3'-untranslated region. In this study, we identified VTS1 as a multi-copy suppressor of dna2-K1080E, a lethal mutant allele of DNA2 that lacks DNA helicase activity. The suppression was allele-specific, since overexpression of Vts1 did not suppress the temperature-dependent growth defects of dna2Delta405N devoid of the N-terminal 405-amino-acid residues. Purified recombinant Vts1 stimulated the endonuclease activity of wild-type Dna2, but not the endonuclease activity of Dna2Delta405N, indicating that the activation requires the N-terminal domain of Dna2. Stimulation of Dna2 endonuclease activity by Vts1 appeared to be the direct cause of suppression, since the multi-copy expression of Dna2-K1080E suppressed the lethality observed with its single-copy expression. We found that vts1Delta dna2Delta405N and vts1Deltadna2-7 double mutant cells displayed synergistic growth defects, in support of a functional interaction between two genes. Our results provide both in vivo and in vitro evidence that Vts1 is involved in lagging strand synthesis by modulating the Dna2 endonuclease activity that plays an essential role in Okazaki fragment processing.


Asunto(s)
ADN Helicasas/metabolismo , ADN/metabolismo , Proteínas de Unión al ARN/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Alelos , Núcleo Celular/química , ADN Helicasas/genética , Proteínas de Unión al ADN/metabolismo , Endodesoxirribonucleasas/genética , Endodesoxirribonucleasas/metabolismo , Endonucleasas de ADN Solapado/metabolismo , Mutación , Proteínas de Unión al ARN/análisis , Proteínas de Unión al ARN/genética , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/crecimiento & desarrollo , Proteínas de Saccharomyces cerevisiae/análisis , Proteínas de Saccharomyces cerevisiae/genética , Supresión Genética
10.
Polymers (Basel) ; 14(3)2022 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-35160614

RESUMEN

Recently, sustainable development has attracted significant global attention. Toward this, several studies have been performed on the development of alternative aggregates for mortar or concrete to prevent environmental damage and rapid depletion of natural aggregates. In this study, we investigated the applicability of a chitosan-based polymer (CBP), a biomimetic polymer, to cement mortar using steel slag as a fine aggregate. The CBP was synthesized via an amide coupling reaction among chitosan, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and 3-(3,4-dihydroxyphenyl)propionic acid. Upon addition to cement mortar using natural sand or a blast furnace slag aggregate, the CBP contributed toward increasing the compressive strength and tensile strength. However, in mortar mixes using a ferronickel slag aggregate, the tensile strength decreased by ~5.7-25.4% upon CBP addition. Moreover, the CBP reduced the total charge passed through the mixes. In particular, in the mortar mix using the steel slag aggregate, the CBP showed improved chloride-ion penetration resistance. The results showed that the as-prepared CBP was a suitable improving agent and exhibited promising compatibility with cement composites containing steel slag aggregates.

11.
Materials (Basel) ; 15(5)2022 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-35269197

RESUMEN

With the trend toward taller and larger structures, the demand for high-strength and lightweight cement concrete has increased in the construction industry. Equipment for transporting ready-mixed concrete is frequently used to bring concrete to construction sites, and washing this equipment generates a large amount of recycled water, which is an industrial by-product. In this study, we recycled this water as the pre-wetting water for lightweight aggregate and as mixing water, and we substituted blast furnace slag powder (BS) and fly ash (FA) as cementitious materials (Cm). In addition, we evaluated the fluidity, compressive strength, tensile strength, drying shrinkage, and accelerated carbonation depth of lightweight ternary cementitious mortars (TCMs) containing artificial lightweight aggregate and recycled water. The 28-day compressive strengths of the lightweight TCM specimens with BS and FA were ~47.2-51.7 MPa, except for the specimen with 20% each of BS and FA (40.2 MPa), which was higher than that of the control specimen with 100% OPC (45.9 MPa). Meanwhile, the 28-day tensile strengths of the lightweight TCM specimens containing BS and FA were ~2.81-3.20 MPa, which are ~13.7-29.5% higher than those of the control specimen. In this study, the TCM specimen with 5% each of BS and FA performed the best in terms of the combination of compressive strength, tensile strength, and carbonation resistance.

12.
Materials (Basel) ; 15(19)2022 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-36234114

RESUMEN

Several studies have been reported on self-healing concrete using bacteria, admixtures, and microcapsules. Among these self-healing techniques, encapsulating cement-based materials is advantageous in that large amounts of self-healing material can be contained in a capsule and released at the cracked site for a targeted reaction. This study produced a powder compacted capsule (PCC) using the droplet and blended manufacturing methods to encapsulate cementitious materials. This study refers to the PCCs as droplet-PCC (D-PCC) and blended-PCC (B-PCC) according to the manufacturing method used. The fluidity, compressive strength, carbonation, drying shrinkage, and water permeability of cement mortar with PCCs were evaluated. The test results show that the flow of the mortar sample using D-PCC was slightly higher than that of the mortar using B-PCC. The compressive strength of the mortar sample with B-PCC was generally higher than that of the mortar sample with D-PCC. The compressive strength of the B-PCC2 sample (with 0.2% of B-PCC) was the highest at all curing ages. This may be because the B-PCC fracture load was higher than that of the D-PCC. In addition, more hydrates were observed in the B-PCC sample than in the D-PCC sample. A crack healing effect was observed in the samples with PCC, regardless of the PCC type. The effect was the greatest in the B-PCC6 sample (with 0.6% of B-PCC). The results of this study provide a reference for the PCC type and mix ratio that would yield the best mechanical properties and crack healing effect.

13.
Polymers (Basel) ; 14(9)2022 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-35566976

RESUMEN

Cement concrete is the most commonly used building and construction material worldwide because of its many advantages. Over time, however, it develops cracks due to shrinkage and tension, which may lead to premature failure of the entire structure. Recently, the incorporation of polymers has been explored to improve the overall strength and durability of cement concrete. In this study, two types of chitosan-based bio-inspired polymers (a-BIP and b-BIP) were synthesized and mixed with cement mortar in different proportions (5-20%). The fluidity of the resulting mixtures and the properties of the hardened samples, such as the compressive and tensile strengths, drying shrinkage, and carbonation resistance, were evaluated. The characteristics of the polymers were tuned by varying the pH during their syntheses, and their structures were characterized using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy. After 28 days of aging, all samples containing BIPs (35.9-41.4 MPa) had noticeably higher compressive strength than the control sample (33.2 MPa). The tensile strength showed a similar improvement (up to 19.1%). Overall, the mechanical properties and durability of the samples were separately dependent on the type and amount of BIP.

14.
Materials (Basel) ; 14(19)2021 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-34640276

RESUMEN

Recently, interest in environmentally friendly development has increased worldwide, especially in the construction industry. In this study, blast furnace slag powder (BFSP) and mixed steel fine aggregates were applied to cement mortars to reduce the environmental damage caused by the extraction of natural aggregate and to increase the recycling rate of steel by-products in the construction industry. We investigated the fluidity, compressive strength, tensile strength, accelerated carbonation depth, and chloride ion penetration resistance of mortars with steel slag aggregate and their dependence on the presence or absence of BFSP. Because the recycling rate of ferronickel slag is low and causes environmental problems, we considered mortar samples with mixed fine aggregates containing blast furnace slag fine aggregate (BSA) and ferronickel slag fine aggregate (FSA). The results showed that the 7-day compressive strength of a sample containing both 25% BSA and 25% FSA was nearly 14.8% higher than that of the control sample. This trend is likely due to the high density and angular shape of steel slag particles. The 56-day compressive strength of the sample with BFSP and 50% FSA was approximately 64.9 MPa, which was higher than that of other samples with BFSP. In addition, the chloride ion penetrability test result indicates that the use of BFSP has a greater effect than the use of steel slag aggregate on the chloride ion penetration resistance of mortar. Thus, the substitute rate of steel slag as aggregate can be substantially enhanced if BFSP and steel slag aggregate are used in an appropriate combination.

15.
Materials (Basel) ; 14(18)2021 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-34576627

RESUMEN

Recently, with increasingly stringent environmental regulations and the depletion of natural aggregate resources, high-quality aggregates have become scarce. Therefore, significant efforts have been devoted by the construction industry to improve the quality of concrete and achieve sustainable development by utilizing industrial by-products and developing alternative aggregates. In this study, we use amorphous metallic fibers (AMFs) to enhance the performance of mortar with steel slag aggregate. Testing revealed that the 28-day compressive strength of the sample with steel slag aggregate and AMFs was in the range of 48.7-50.8 MPa, which was equivalent to or higher than that of the control sample (48.7 MPa). The AMFs had a remarkable effect on improving the tensile strength of the mortar regardless of the use of natural aggregates. With AMFs, the drying shrinkage reduction rate of the sample with 100% steel slag aggregate was relatively higher than that of the sample with 50% natural fine aggregate. Furthermore, the difference in the drying shrinkage with respect to the amount of AMFs was insignificant. The findings can contribute to sustainable development in the construction industry.

16.
IEEE Trans Neural Netw Learn Syst ; 32(11): 5082-5092, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-33095717

RESUMEN

Despite the success of batch normalization (BatchNorm) and a plethora of its variants, the exact reasons for its success are still shady. The original BatchNorm article explained it as a mechanism that reduces the internal covariate shift (ICS), i.e., the distribution shifts in the input of the layers during training. Recently, some articles manifested skepticism on this hypothesis and provided alternative explanations for the success of BatchNorm, such as the applicability of very high learning rates and the ability to smooth the landscape in optimization. In this work, we counter these alternative arguments by demonstrating the importance of reduction in ICS following an empirical approach. We demonstrated various ways to achieve the abovementioned alternative properties without any performance boost. In this light, we explored the importance of different BatchNorm parameters (i.e., batch statistics and affine transformation parameters) by visualizing their effectiveness in the performance and analyzed their connections with ICS. Afterward, we showed a different normalization scheme that fulfills all the alternative explanations except reduction in ICS. Despite having all the alternative properties, we observed its poor performance, which nullifies the alternative claims, rather signifies the importance of the ICS reduction. We performed comprehensive experiments on many variants of BatchNorm, finding that all of them similarly reduce ICS.

17.
Materials (Basel) ; 14(21)2021 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-34771921

RESUMEN

There have been numerous recent studies on improving the mechanical properties and durability of cement composites by mixing them with functional polymers. However, research into applying modified biopolymer such as catechol-functionalized chitosan to cement mortar or concrete is rare to the best of our knowledge. In this study, catechol-functionalized chitosan (Cat-Chit), a well-known bioinspired polymer that imitates the basic structures and functions of living organisms and biological materials in nature, was synthesized and combined with cement mortar in various proportions. The compressive strength, tensile strength, drying shrinkage, accelerated carbonation depth, and chloride-ion penetrability of these mixes were then evaluated. In the ultraviolet-visible spectra, a maximum absorption peak appeared at 280 nm, corresponding to catechol conjugation. The sample containing 7.5% Cat-Chit polymer in water (CPW) exhibited the highest compressive strength, and its 28-day compressive strength was ~20.2% higher than that of a control sample with no added polymer. The tensile strength of the samples containing 5% or more CPW was ~2.3-11.5% higher than that of the control sample. Additionally, all the Cat-Chit polymer mixtures exhibited lower carbonation depths than compared to the control sample. The total charge passing through the samples decreased as the amount of CPW increased. Thus, incorporating this polymer effectively improved the mechanical properties, carbonation resistance, and chloride-ion penetration resistance of cement mortar.

18.
J Microbiol ; 59(4): 401-409, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33779953

RESUMEN

Eukaryotic genomes contain many duplicated genes closely located with each other, such as the hexose transporter (HXT) genes in Saccharomyces cerevisiae. They can potentially recombine via single-strand annealing (SSA) pathway. SSA between highly divergent sequences generates heteroduplex DNA intermediates with many mismatches, which can be corrected by mismatch repair (MMR), resulting in recombinant sequences with a single junction point. In this report, we demonstrate that SSA between HXT1 and HXT4 genes in MMR-deficient yeast cells produces recombinant genes with multiple-junctions resulting from alternating HXT1 and HXT4 tracts. The mutations in MMR genes had differential effects on SSA frequencies; msh6Δ mutation significantly stimulated SSA events, whereas msh2Δ and msh3Δ slightly suppressed it. We set up an assay that can identify a pair of recombinant genes derived from a single heteroduplex DNA. As a result, the recombinant genes with multiple-junctions were found to accompany genes with single-junctions. Based on the results presented here, a model was proposed to generate multiple-junctions in SSA pathway involving an alternative short-patch repair system.


Asunto(s)
Reparación de la Incompatibilidad de ADN , Proteínas de Transporte de Monosacáridos/genética , Ácidos Nucleicos Heterodúplex/genética , Saccharomyces cerevisiae/genética , Disparidad de Par Base , ADN de Hongos , Proteínas de Unión al ADN/genética , Proteínas Fúngicas/genética , Genes Fúngicos , Mutación , Recombinación Genética
19.
Materials (Basel) ; 14(9)2021 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-33922729

RESUMEN

Recently, interest in sustainable development has been increased. In this regard, efforts have been made to prevent environmental pollution, and research on the recycling of construction industry byproducts has been actively conducted in the construction industry. In South Korea, about 20 million tons of waste wash water from the ready-mixed concrete production process are generated, and some of them are recycled using recycling facilities in a ready-mixed concrete plant, but a significant portion of them is discharged or landfilled without permission, causing environmental problems. To increase the recycling rate of steel slag and reduce environmental pollution in the construction industry, we simultaneously applied blast furnace slag fine aggregate (BSFA) and recycled water (RW) to cement mortar. In this study, to examine the feasibility of RW and BSFA, we evaluated the fluidity, compressive strength, tensile strength, drying shrinkage, carbonation depth, and chloride penetration resistance of cement mortar using RW and BSFA. From the test results, the 28-day compressive strengths of all samples using RW and BSFA were higher than that of the control sample. In the case of samples using RW, as the BSFA replacement ratio was increased, the carbonation depth of the samples decreased. Therefore, when RW and BSFA are used properly, the mechanical properties of cement mortar, carbonation resistance, and chloride ion penetration resistance are expected to be effectively improved.

20.
IEEE J Biomed Health Inform ; 25(7): 2686-2697, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33264095

RESUMEN

OBJECTIVE: With the scenario of limited labeled dataset, this paper introduces a deep learning-based approach that leverages Diabetic Retinopathy (DR) severity recognition performance using fundus images combined with wide-field swept-source optical coherence tomography angiography (SS-OCTA). METHODS: The proposed architecture comprises a backbone convolutional network associated with a Twofold Feature Augmentation mechanism, namely TFA-Net. The former includes multiple convolution blocks extracting representational features at various scales. The latter is constructed in a two-stage manner, i.e., the utilization of weight-sharing convolution kernels and the deployment of a Reverse Cross-Attention (RCA) stream. RESULTS: The proposed model achieves a Quadratic Weighted Kappa rate of 90.2% on the small-sized internal KHUMC dataset. The robustness of the RCA stream is also evaluated by the single-modal Messidor dataset, of which the obtained mean Accuracy (94.8%) and Area Under Receiver Operating Characteristic (99.4%) outperform those of the state-of-the-arts significantly. CONCLUSION: Utilizing a network strongly regularized at feature space to learn the amalgamation of different modalities is of proven effectiveness. Thanks to the widespread availability of multi-modal retinal imaging for each diabetes patient nowadays, such approach can reduce the heavy reliance on large quantity of labeled visual data. SIGNIFICANCE: Our TFA-Net is able to coordinate hybrid information of fundus photos and wide-field SS-OCTA for exhaustively exploiting DR-oriented biomarkers. Moreover, the embedded feature-wise augmentation scheme can enrich generalization ability efficiently despite learning from small-scale labeled data.


Asunto(s)
Diabetes Mellitus , Retinopatía Diabética , Angiografía , Retinopatía Diabética/diagnóstico por imagen , Fondo de Ojo , Humanos , Retina/diagnóstico por imagen , Tomografía de Coherencia Óptica
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA