Twist Level Research Articles

Flax roving twisting preparation for weaving and effect of the weft layers number on the physical and mechanical properties of 3D interlock flax fabric

The feasibility to manufacture a 3D warp interlock preform from 1000 Tex flax roving is investigated by means of a prototype machine developed to GEMTEX laboratory. The provided flax roving has low tensile failure load because of lack of twist so it isn’t suitable for weaving. The first step was dedicated to improve the tensile properties of the roving through twisting process and identifies the optimal twist level. Experimental campaign is conducted by applying different twist level and evaluates the roving tensile properties. The ultimate tensile load increases as roving twist level increases until a threshold at which the tensile load declines as twist level increases. While the failure strain increases continuously as twist level increases. Five fabrics are produced with the same flax roving, 3D weave architecture and warp number and weft column number per unit length. Only the number of weft layers varies. The physical and tensile properties of these five flax fabrics are characterized experimentally. A considerable effect on the thickness and areal density of the fabric is reported. The difference in the waviness length between the two types of the warp roving (reinforcing and binding) has a significant impact on the tensile behavior of the fabrics in warp direction through the appearance of two phases on the force-strain curve. Otherwise, the variation of the number of layers does not induce a remarkable impact of the fabric structure on the tensile performance of the constituting roving.

A study on the viscoelastic behaviors of tire cords using dynamic mechanical analysis

Design of experiments was adopted to evaluate the effect of selected test parameters on the viscoelastic behaviors of polyester tire cords through dynamic mechanical analysis systematically. Design of experiments results showed that temperature, static load, and dynamic amplitude had significant effects on the responses of complex modulus (E*) and Tan δ. Furthermore, temperature had significant interactions with static load and dynamic amplitude factors on the responses. None of the test parameters had any significant effect on the response of glass transition temperature (Tg). Below Tg, thermoplastic tire cords exhibited a high and constant dynamic modulus, whereas, beyond this point, the modulus decreased dramatically. The thermosetting tire cords exhibited a constant performance due to an ordered and tight molecular chain arrangement. The magnitude of Tan δ reached its peak value at Tg due to the increase in internal friction as a result of increasing temperature. The dynamic modulus increased and Tan δ decreased with the increasing static load as a result of restricting the mobility of chain segments. The reverse was true when the dynamic amplitude increased, most probably because of higher chain segment mobility and early stage of polymer chain slippage. Activation energy (Ea), derived from Arrhenius equation, can be used to predict its long-term performance. Tg shifted to a higher temperature as the frequency increased. In addition, by increasing the twist level of the polyester tire cord, the dynamic modulus decreased and Tan δ increased. Tg was evaluated as the upper limit working temperature, Tan δ was related to energy dissipation, and E* determined the overall performance of the tire cord. By displacing Tg to a higher temperature, reducing the magnitude of Tan δ and increasing the dynamic modulus are of great importance to a tire cord’s performance.

Electrical resistive heating characterization of conductive hybrid staple spun yarns

Development of heating fabrics has a great potential in numerous applications. Heating fabrics can be developed by various approaches each having its own strengths and weaknesses. Incorporating staple fibre spun conductive yarn in the development of lightweight heating pads offers the advantage of obtaining required heating effect while maintaining flexibility, durability and comfort of the developed fabric. This study aimed at developing a conductive hybrid spun yarn composed of polyester and stainless staple fibers and characterizing its thermal behaviour in response to changes in its structural and procedural parameters. The effect of three variables namely yarn twist coefficient, applied voltage and tension on the yarn during testing, was investigated on thermal behavior of the yarn. Among the three, the applied voltage was found to dominantly control the temperature and hence the heating effect of the hybrid yarn. Yarn twist coefficient, which makes the yarn structure of the same fineness more compact at higher twist levels, was found to improve the heating effect at increased twist level at an applied voltage. However, changes in the tension on the yarn during the test was found to be not affecting the yarn temperature, thus producing a steady heating effect under varying tensions. The study shows that other than changing the applied voltage, the heating effect of the yarn can be improved by changing its twist level which controls the compactness of the yarn and thus different products with required thermal behavior can be tailored.

NADPH oxidase 1 mediates caerulein-induced pancreatic fibrosis in chronic pancreatitis

Inflammatory disorders of the pancreas are divided into acute (AP) and chronic (CP) forms. Both states of pancreatitis are a result of pro-inflammatory mediators, including reactive oxygen species (ROS). One of the sources of ROS is NADPH oxidase (Nox). The rodent genome encodes Nox1-4, Duox1 and Duox2. Our purpose was to assess the extent to which Nox enzymes contribute to the pathogenesis of both AP and CP using Nox-deficient mice. Using RT-PCR, Nox1 was found in both isolated mouse pancreatic acini and pancreatic stellate cells (PaSCs). Subsequently, mice with genetically deleted Nox1 were further studied and showed that the histo-morphologic characteristics of caerulein-induced CP, but not caerulein-induced AP, was ameliorated in Nox1 KO mice. We also found that the lack of Nox1 impaired caerulein-induced ROS generation in PaSCs. Using Western blotting, we found that AKT mediates the fibrotic effect of Nox1 in a mouse model of CP. We also found a decrease in phospho-ERK and p38MAPK levels in Nox1 KO mice with CP, but not with AP. Both CP-induced TGF-β up-regulation and NF-ĸB activation were impaired in pancreas from Nox1 KO mice. Western blotting indicated increases in proteins involved in fibrosis and acinar-to-ductal metaplasia in WT mice with CP. No change in those proteins were observed in Nox1 KO mice. The lack of Nox1 lowered mRNA levels of CP-induced matrix metalloproteinase MMP-9 and E-cadherin repressor Twist in PaSCs. ConclusionNox1-derived ROS in PaSCs mediate the fibrotic process of CP by activating the downstream redox-sensitive signaling pathways AKT and NF-ĸB, up-regulating MMP-9 and Twist, and producing α-smooth muscle actin and collagen I and III.

Dietary Flavonoids Luteolin and Quercetin Inhibit Migration and Invasion of Squamous Carcinoma through Reduction of Src/Stat3/S100A7 Signaling.

Flavonoids are well-known antioxidants and have shown the ability to prevent tumor formation and recurrence. Especially in dietary flavonoids, they have provided convenience and consistence of intake for long-term prevention of tumor formation. Previous reports suggested that S100 calcium-binding protein A7 (S100A7) might activate epithelial–mesenchymal transition (EMT) signaling and promote the metastasis of tumor cells; however, the regulatory signaling was unclear. In this study, we found that S100A7 was highly expressed in cancer cells and could be reduced by luteolin (Lu) and quercetin (Qu) through Src/Stat3 signaling. We found that the protein levels of S100A7, phosphorylated Src (p-Src), and p-Stat3 were increased in A431-III cells. Flavonoids Lu and Qu reduce protein levels of p-Src, p-Stat3 and S100A7 in A431-III cells. Treatment of A431-III cells with Src inhibitor SU6656 and Stat3 inhibitor S3I-201 also reduced the protein levels of S100A7. Transactivation activity of 5′-upstream regions of S100A7 was activated by Stat3 but was reduced by treatment with Lu, Qu, SU6656 and S3I-201. The treatment also reduced the migratory and invasive abilities of A431-III cells. In a further analysis of EMT markers, the protein level of E-cad increased and that of Twist decreased after treatment with the inhibitors and flavonoids. Overexpression of S100A7 decreased the protein level of E-cad and increased the Twist level, whereas knockdown of S100A7 had the opposite effects. Treatment with S3I-201, Lu and Qu, compared to the control, were found to decrease metastasis of tumor cells in zebrafish larvae. These results suggest that Lu and Qu may inhibit Src/Stat3/S100A7 signaling to reduce tumorigenesis of cancer cells.

Expression and significance of c-kit and epithelial-mesenchymal transition (EMT) molecules in thymic epithelial tumors (TETs).

To investigate the expression and significance of c-kit and epithelial-mesenchymal transition (EMT) molecules (E-cadherin, N-cadherin, Twist, Snail) in thymic epithelial tumors (TETs). The tissue microarray technology and immunohistochemistry MaxVisionTM-use kit were used to detect the expression of c-kit and EMT molecular markers in 150 cases of paraffin sections of TET tissue and analysis the correlation between c-kit and EMT molecules and explore the malignancy and the relationship of clinicopathological parameters between c-kit, EMT molecules and TETs. The expression difference of c-kit and EMT molecular markers (E-cadherin, N-cadherin, Snail, Twist) in TETs subtypes was statistically significant (P<0.01) and their positive expression rate of thymic carcinoma was significantly higher than that in thymoma, and the difference was statistically significant, respectively (P<0.01). There is a negative correlation between the expression of c-kit and E-cadherin as well as a positive correlation between the expression level of c-kit, N-cadherin, Twist, and Snail. Furthermore, E-cadherin was negatively correlated with N-cadherin, Twist, and Snail while N-cadherin expression was positively correlated with Twist, Snail. Five indicators (c-kit, E-cadherin, N-cadherin, Twist, and Snail) may determine the malignancy of TETs, especially for distinguishing thymoma and thymic carcinoma.

Deciphering the Gene Regulatory Landscape Encoded in DNA Biophysical Features.

SummaryGene regulation in higher organisms involves a sophisticated interplay between genetic and epigenetic mechanisms. Despite advances, the logic in selective usage of certain genomic regions as regulatory elements remains unclear. Here we show that the inherent biophysical properties of the DNA encode epigenetic state and the underlying regulatory potential. We find that the propeller twist (ProT) level is indicative of genomic location of the regulatory elements, their strength, the affinity landscape of transcription factors, and distribution in the nuclear 3D space. We experimentally show that ProT levels confer increased DNA flexibility and surface accessibility, and thus potentially primes usage of high ProT regions as regulatory elements. ProT levels also correlate with occurrence and phenotypic consequences of mutations. Interestingly, cell-fate switches involve a transient usage of low ProT regulatory elements. Altogether, our work provides unprecedented insights into the gene regulatory landscape encoded in the DNA biophysical features.

CD36 promotes the epithelial\u2013mesenchymal transition and metastasis in cervical cancer by interacting with TGF-\u03b2

BackgroundAccumulating evidence indicates that CD36 initiates metastasis and correlates with an unfavorable prognosis in cancers. However, there are few reports regarding the roles of CD36 in initiation and metastasis of cervical cancer.MethodsUsing immunohistochemistry, we analyzed 133 cervical cancer samples for CD36 protein expression levels, and then investigated the correlation between changes in its expression and clinicopathologic parameters. The effect of CD36 expression on the epithelial–mesenchymal transition (EMT) in cervical cancer cells was evaluated by Western immunoblotting analysis. In vitro invasion and in vivo metastasis assays were also used to evaluate the role of CD36 in cervical cancer metastasis.ResultsIn the present study, we confirmed that CD36 was highly expressed in cervical cancer samples relative to normal cervical tissues. Moreover, overexpression of CD36 promoted invasiveness and metastasis of cervical cancer cells in vitro and in vivo, while CD36 knockdown suppressed proliferation, migration, and invasiveness. We demonstrated that TGF-β treatment attenuated E-cadherin expression and enhanced the expression levels of CD36, vimentin, slug, snail, and twist in si-SiHa, si-HeLa, and C33a–CD36 cells, suggesting that TGF-β synergized with CD36 on EMT via active CD36 expression. We also observed that the expression levels of TGF-β in si-SiHa cells and si-HeLa cells were down-regulated, whereas the expression levels of TGF-β were up-regulated in C33a–CD36 cells. These results imply that CD36 and TGF-β interact with each other to promote the EMT in cervical cancer.ConclusionsOur findings suggest that CD36 is likely to be an effective target for guiding individualized clinical therapy of cervical cancer.

Leptin Promotes Expression of EMT-Related Transcription Factors and Invasion in a Src and FAK-Dependent Pathway in MCF10A Mammary Epithelial Cells.

Leptin is one of the main adipokines secreted in breast tissue. Leptin promotes epithelial–mesenchymal transition (EMT), cell migration and invasion in epithelial breast cells, leading to tumor progression. Although, the molecular mechanisms that underlie these events are not fully understood, the activation of different signaling pathways appears to be essential. In this sense, the effects of leptin on the activation of kinases like Src and FAK, which regulate signaling pathways that activate the EMT program, are not completely described. Therefore, we investigated the involvement of these kinases using an in vitro model for leptin-induced EMT process in the non-tumorigenic MCF10A cell line. To this end, MCF10A cells were stimulated with leptin, and Src and FAK activation was assessed. Specific events occurring during EMT were also evaluated in the presence or absence of the kinases’ chemical inhibitors PP2 and PF-573228. For instance, we tested the expression and subcellular localization of the EMT-related transcription factors Twist and β-catenin, by western blot and immunofluorescence. We also evaluated the secretion and activation of matrix metalloproteases (MMP-2 and MMP-9) by gelatin zymography. Invasiveness properties of leptin-stimulated cells were determined by invadopodia formation assays, and by the Transwell chamber method. Our results showed that leptin promotes EMT through Src and FAK activation, which leads to the secretion and activation of MMP-2 and MMP-9, invadopodia formation and cell invasion in MCF10A cells. In conclusion, our data suggest that leptin promotes an increase in the expression levels of Twist and β-catenin, the secretion of MMP-2, MMP-9, the invadopodia formation and invasion in MCF10A cells in a Src and FAK-dependent manner.

Interleukin-8/β-catenin mediates epithelial-mesenchymal transition in ameloblastoma.

Epithelial-mesenchymal transition (EMT) is important in the tooth development and tumor invasion. We investigated the effect of interleukin-8 (IL-8) on the EMT process in primary-cultured ameloblastoma tumor cells (AM-P) and ameloblastoma immortalized tumor cells (AM-L) and its underlying mechanism. IL-8 levels in ameloblastomas were detected by immunofluorescence staining and ELISA. AM-P cells and AM-L cells were stimulated with IL-8, and EMT transcription factors, total β-catenin and phosphorylated-β-catenin (p-β-catenin) levels were determined by Western blot analysis and immunofluorescence staining. β-catenin siRNA was used to knockdown β-catenin expression in AM-P cells and AM-L cells stimulated with IL-8. IL-8 was highly expressed in the solid ameloblastomas. IL-8 promoted the EMT process in ameloblastoma tumor cells in vitro, as evidenced by decreased E-cadherin and increased vimentin, twist and zeb1 levels. IL-8 also increased total β-catenin and p-β-catenin expression in ameloblastoma tumor cells, and β-catenin knockdown partially inhibited the EMT process in tumor cells, as evidenced by increased E-cadherin, and decreased vimentin and zeb1 levels. IL-8 could promote EMT in ameloblastoma tumor cells by activating β-catenin and its downstream transcription factor zeb1.

Fabrication of capacitive yarn torsion sensors based on an electrospinning coating method

AbstractA yarn‐based capacitive torsion sensor was produced using a simple electrospinning coating method. It was expected that nonwoven nanofiber mats, as a coating layer, would exhibit excellent performance owing to their high surface area and porous three‐dimensional nonwoven structure, which is more deformable than that of films. The electrospinning process was investigated by image analysis to generate a suitable structure of the nanofiber coating layer. The thickness of the layer was controlled by varying the electrospinning coating time (10, 20 and 30 min). Yarn sensors with coating layers of different thicknesses were manufactured by twisting two coated fibers, while simultaneously measuring the capacitance. The best sensitivity was observed with the 10 min coated yarn, due to the largest valid twist level range. It is proposed that the distance between the electrodes and the dielectric constant of the material play an important and complex role in the capacitive response of the twisted yarn, caused by the porous three‐dimensional nonwoven structure of the coated layer and the molecular mobility of the polymer. This simple coating method is expected to be useful in a wide range of applications, such as wearable devices, by facilitating convenient fabrication and repair of the flexible sensors. Moreover, high performance of the sensor could be realized due to the structural advantage of the sensing layer. © 2019 Society of Chemical Industry

Long noncoding RNA MIR31HG abrogates the availability of tumor suppressor microRNA-361 for the growth of osteosarcoma.

PurposeLong noncoding RNA (LncRNA) containing microRNA host gene is an interesting type of LncRNA. MicroRNA-31 (miR-31)-host gene LncRNA (MIR31HG) have been recognized as an oncogene in many cancers, but not in osteosarcoma (OS). Interestingly, MIR31HG/miR-31 could not regulate each other’s expression in certain cancer, suggesting that the role of MIR31HG in cancer is independent of miR-31. We here investigated the function and potential mechanism of MIR31HG in OS.MethodsOS tissues and adjacent non-tumor tissues (n=40) were collected to determine the expressions of MIR31HG by paired t-test. We here identified the miRNAs predicted to be bound to MIR31HG and investigated the impacts of MIR31HG on cell growth and metastasis of OS cells by CCK-8, flow cytometry, Transwell assay, Western blot, etc. in vitro and in vivo.ResultsMIR31HG was upregulated in OS tissues and OS cell lines. The patients with high expression of MIR31HG have high tumor stages and distant metastasis. Tumor suppressor miR-361, but not miR-31, was confirmed to be sponged directly by MIR31HG in OS cells and was down-regulated in OS cell lines. Knockdown of MIR31HG restored the expression of miR-361. Restoration of miR-361 level in Saos-2 and U2OS cells induced cell apoptosis and G1/S arrest, inhibited proliferation and migration, which was, however, abrogated by MIR31HG. Mechanistically, cell growth and metastasis-related target genes of MIR-361 including VEGF, FOXM1 and Twist were de-repressed in OS cells by MIR31HG overexpression, leading to upregulated BCL2, CCND1 and epithelial–mesenchymal transition (EMT) phenotype. Patients with high expression of MIR31HG also showed more VEGF, FOXM1 and Twist levels. Overexpression of MIR31HG in vivo also promoted tumor growth via inhibition of miR-361 signals and elevated the expression of VEGF, FOXM1 and Twist for tumor growth.ConclusionMIR31HG acts as an oncogene in OS for tumor progression via regulation of tumor suppressor miR-361 and its target genes.

Piperine inhibits the transformation of endothelial cells into fibroblasts

Objective: To investigate the role of piperine on the transformation of endothelial cells into fibroblasts. Methods: Cultured human umbilical vein endothelial cells (HUVECs, 4-6 passage) were used for the main experiments. The transformation models of endothelial cells into fibroblasts were induced by transforming growth factor β (TGF-β) stimulation. HUVECs were divided into 6 groups: control group, TGF-β group and 4 groups treated with various concentrations of piperine (1, 5, 10, 20 μmol/L). CKK-8 was used to detect cell proliferation. The CD31/α-smooth muscle actin (α-SMA) expression level was detected by fluorescent staining. The vascular endothelial cadherin (VE-cadherin)/vimentin expression was detected by immunofluorescence staining. RT-PCR was used detect the mRNA expressions of transformation markers. Western blot was used to detect the protein expression of snail and twist. Results: TGF-β increased HUVECs proliferation (P<0.05), which could be significantly inhibited by 10 and 20 μmol/L of piperine, but not by 1 and 5 μmol/L of piperine. Immunofluorescence results demonstrated that TGF-β increased HUVECs transformation to fibroblasts as shown by downregulated expression of endothelial markers CD31, VE-cadherin, and upregulated expression of α-SMA and vimentin, again, these effects could be attenuated by 10 and 20 μmol/L piperine. The expression levels of collagen type Ⅰ and type Ⅲ were significantly higher in TGF-β group than in control group (P<0.05), significantly lower in TGF-β+10 μmol/L piperine group and TGF-β+20 μmol/L piperine group than in TGF-β group (P<0.05).In addition, RT-PCR results showed that TGF-β increased mRNA expression of transformation markers (snail1, snail2, twist1, twist2), while 10 and 20 μmol/L of piperine could significantly downregulated the mRNA expressions of these markers. The protein expression levels of snail and twist were significantly higher in TGF-β group than in control group (both P<0.05), which was significantly lower in TGF-β+20 μmol/L piperine group than in TGF-β group (both P<0.05). Conclusions: Piperine can inhibit the transformation of endothelial cells into fibroblasts. This effect might be viewed as one of the potential mechanisms of reduced myocardial fibrosis post piperine treatment.

Abstract 2861: ACKR3 promotes cell metastasis via activating TGF-beta 1/Smad signaling in head and neck squamous cell carcinoma

Abstract Background: The atypical chemokine receptor, ACKR3, has been shown to play as a tumor promoter, which is upregulated in various types of cancer. However, the biological role of ACKR3 and its underlying mechanism in head and neck squamous cell carcinoma (HNSCC) is still unknown. In this study, we investigated the functional role of ACKR3 and the underlying molecular mechanism of tumor progression in HNSCC. Methods: We examined the ACKR3 expression and its association with clinicopathological characteristics in 103 cases of HNSCC by immunohistochemical staining. The biological roles of ACKR3- and ACKR3-induced downstream signaling were investigated in HNSCC cell through ACKR3 overexpression and knockdown of ACKR3 in vitro and in vivo. Results: We detected differential expression of ACKR3 in HNSCC cells and tissues. High ACKR3 expression was significantly associated with invasion depth of tumor (T status; P = 0.007), lymph node involvement (N status; P = 0.004), and higher stage III/IV (P = 0.02). Overexpression of ACKR3 dramatically enhanced cell migration and invasion in HNSCC cells in vitro, and promoted lymph node metastasis in vivo. ACKR3 overexpression also induced the epithelial-mesenchymal transition. Vimentin, Slug, and Twist were increased but E-cadherin and Ep-CAM were decreased by ACKR3 expression. Upregulation of TGF-β1 was observed in ACKR3 overexpression, and TGF-β1/Smad signaling activation and Akt phosphorylation were induced in HNSCC cells with ACKR3 overexpression. Treatment with a PI3K inhibitor reduced Slug and Twist levels while suppression of Smad2/3 signaling by siRNA reduced Akt phosphorylation, as well as Slug and Twist. Furthermore, inhibition of Smad2/3 decreased tumor cell migration and invasion in HNSCC. ACKR3 knockdown using siRNA in HNSCC cells reduced the secretion of TGF-β1 and also recovered the cell migratory and invasive behavior of HNSCC cells. Conclusions: ACKR3 expression was associated with an aggressive tumor behavior in HNSCC. ACKR3 contributed to migration and invasion of HNSCC cell through the TGF-β1/Smad signaling axis and epithelial-mesenchymal transition in vitro, and was involved in lymph node metastasis in vivo, suggesting that ACKR3 plays an important role during HNSCC progression and metastasis. Citation Format: Nayoung Kim, Solbi Kim, Mina Joo, Heung Jin Jeon, Myung-Won Lee, Hyewon Ryu, Hyo Jin Lee. ACKR3 promotes cell metastasis via activating TGF-beta 1/Smad signaling in head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2861.

MiR-940 inhibits migration and invasion of tongue squamous cell carcinoma via regulatingCXCR2/NF-κB system-mediated epithelial-mesenchymal transition.

Tongue squamous cell carcinoma (TSCC) is one of the most common incident oral cancers, which is accompanied by high rate of metastasis and recurrence. It has been demonstrated that elevated interleukin-8 (IL-8) promoted metastasis of various cancers via regulating epithelial-mesenchymal transition (EMT) process, whereas the accurate mechanism is left to be elucidated. The present work was aimed to investigate the role of microRNA-940 (miR-940)/C-X-C chemokine receptor type 2 (CXCR2) system in the metastasis ability and EMT process of IL-8-treated TSCC cells and further explore the underlying mechanisms. We found that miR-940 up-regulation inhibited IL-8-induced migration and invasion, which could be deprived by CXCR2 silence. We also observed that miR-940 suppressed epithelial marker E-cadherin expression while increased mesenchymal markers N-cadherin and Twist levels in IL-8-stimulated TSCC cells. Besides, IL-8-induced invasion and EMT process of TSCC cells were impeded in the present of the NF-κB inhibitor, PDTC or BAY117082. In conclusion, our data demonstrated that miR-940/CXCR2 system regulated the metastasis of TSCC cells via NF-κB-induced EMT process.

The effect of fabric mass per unit area and blood impact velocity on bloodstain morphology

This paper discusses the effects of thickness, mass per unit area, sett, yarn linear density and twist of calico fabrics (100% cotton, plain woven) on the morphology of passive bloodstains. Horse blood was dropped vertically onto three calico fabrics with different mass per unit areas (85.1 g/m², 163.5 g/m² and 224.6 g/m²). Six different impact velocities were used (1.7 ms−1, 2.9 ms−1, 4.1 ms−1, 4.9 ms−1, 5.1 ms−1 and 5.4 ms−1). The dry bloodstains were largest on the calico with the lightest mass per unit area. The low yarn linear density and large inter-yarn spaces meant that the blood could wick into the yarns from all directions and along the intra-yarn spaces. The calico with the middle mass per unit area had the smallest mean dry bloodstain area for four out of the six velocities. The twist level for this calico was greater than for the calicos with a heavier or lighter mass per unit area. This reduced the amount of wicking which occurred along the yarns due to the tighter yarn structure. The calico with the heaviest mass per unit area had the highest yarn linear density resulting in a thicker fabric, so the blood could not as easily penetrate into the fabric. This resulted in a thicker wet blood layer remaining on the fabric surface, where it gradually wicked vertically into the yarns under gravity. Less wicking along the yarns occurred, resulting in a smaller bloodstain than on the fabric with the lightest mass per unit area. The correlation between impact velocity and mean dry bloodstain area was greater for the calicos with the medium and heaviest mass per unit area than for the calico with the lightest mass per unit area. For the calicos with the medium and heaviest mass per unit area, the distance the blood spread laterally at impact, which increased with the increase in impact velocity, had a greater influence on the dry bloodstain area than the amount of wicking.

Effect of weft yarn twist level on mechanical and sensorial comfort of 100% woven cotton fabrics

Fabric sensory properties are complex concepts which include dimensional changes at small forces such as tensile, shear, compression and bending, surface properties (friction and roughness) plus surface coolness or warmness. The aim of this study was to investigating the effect of weft yarn twist level on sensorial comfort of 100% woven cotton fabrics. Five cotton fabrics were woven with incremental weft yarn twist levels and their tensile and shear strength, pure bending, compression, surface friction and roughness were evaluated using Kawabata Evaluation System and compared. The other sample parameters such as count, thread density and fabric structure were kept constant. Fabric water permeability and its wicking ability were also evaluated. The results showed that as the twist level increased, the fabric tensile, shear and bending properties also increased. This was observed in both the warp and weft direction. At higher level of twist, lower surface friction, less compressibility, less slipperiness (0.264 warp and 0.199 weft direction), rougher surface (0.026 warp and 0.020 weft) and less even surface (2.643 warp and 1.998) were observed. The wicking ability also reduced with the increase in twist level while there was an improvement in water permeability.

Tunable wicking behavior via titanium oxide embedded in polyacrylonitrile nanofiber strings of yarn

The effect(s) of TiO2 nanoparticles on the vertical wicking behavior observed in electrospun polyacrylonitrile (PAN) nanofiber strings of yarn was investigated in this study. The capillary flow was measured in composite nanofiber strings of yarn by means of the image analysis of the rise of colored liquid soaked up in the strings of yarn; the height of liquid rise was determined as a function of time. The kinetics of capillary rise follows the Lucas–Washburn’s equation. The results obtained from the experimental design showed that the rate coefficient of the capillary rise was influenced by TiO2 nanoparticles more than the twist level in nanofiber strings of yarn. For various hot-stretching ratios, the rate of capillary rise decreased with increasing the number of TiO2 nanoparticles and the level of yarn twist. This decreasing trend was more pronounced at higher levels of yarn twist. To find how capillary behavior changed with the release of nanoparticles, the wicking mechanisms were measured at different concentrations of TiO2 nanoparticles in capillary liquid. When TiO2 nanoparticles were used in capillary liquid, they immediately filled the spaces between nanofibers in yarn and the liquid could not rise any more. The present study indicated that the wicking behavior of composite nanofiber strings of yarn was tunable provided that appropriate constructive factors, that is to say, the number of TiO2 nanoparticles and the level of nanofiber yarn twist, were chosen.

Experimental study on the formation of core-spun yarn manufactured on a modified vortex spinning system

Aiming at achieving online monitoring of the yarn formation process of vortex spinning, this paper presents a direct observation method that adopts a charge-coupled device camera fitted with an industrial endoscope that can reach into the nozzle chamber through a small hole drilled on the nozzle wall. Local pressure distortion in the vortex chamber due to the mounting of the observation apparatus was found experimentally. However, the yarn quality was not significantly affected, indicating that the proposed method has the potential to find industrial applications. Based on this method, the formation process of core-spun yarn containing a copper wire manufactured on a modified vortex spinning system is successfully observed. The results show that the core wire is covered by the main strand (core fibers), while the main strand is false-twisted during the yarn formation process. The level of false twist in the main strand fluctuates with time. The level of false twist in the main strand is higher in the upstream region, while it gradually decreases toward the downstream. Mostly, the trailing ends of some fibers are separated from the main strand and expand over the spindle tip to wrap around both the core fibers and core wire to form wrapper fibers in the yarn, while the leading ends of a smaller number of fibers are separated to form wrapper-wild fibers in the yarn. The proposed method can be extended to the study of fiber movement in confined spaces in other textile manufacturing processes.

Wicking Behaviors of Ring and Compact-Siro Ring Spun Yarns with Different Twists

Abstract In this study, the wicking properties of ring and compact-siro ring spun staple yarns were compared. The twist level, which is related to the structure of the staple yarns, was found to significantly influence the wicking property of the two kinds of yarn. Polyester staple fibers with 1.33 dtex × 38 mm were selected as the staple fiber material, and the effect of the twist level on the wicking property was investigated using the capillary rise method. The results show that with a decreasing twist coefficient, the wicking height increases with a decrease in yarn compactness. The compact-siro spun yarn showed better wicking properties owing to it special ply yarn structure. Furthermore, the tension property of the yarns decreased significantly with a decrease in the twist coefficient. Compact-siro spinning was carried out to obtain staple yarns with lower twist coefficients, and the yarns showed great improvement in terms of yarn strength, fiber straightness, and wicking properties. Thus, compact-siro spinning is an efficient method to improve the wicking properties of staple yarns.