79 research outputs found
Estimation of the EMR shielding effectiveness of knit structures
This paper describes the creation of and tests petformed on knit structures of three types (left-right stitch (I), double-layer (II), and double-layer with additional fillings (III)), which contain ferromagnetic materials and electroconductive materials and are designed for individual protection against occupational hazard. The ferromagnetic material is composed of two bunches of twisted filaments of ferromagnetic stainless steel made by Bekaert, Belgium, and the electroconductive material is a thread made of cotton and copper wire covered by silver made by Swiss Shield (R) yarns, Switzerland. Both the ferromagnetic and electroconductive materials form a hybrid yarn. Shielding effectiveness (SE) tests on knit structures were performed by the Central Institute for Labour Protection - National Research Institute, Poland and by the Institute of Architecture of Textiles, Poland. Analysis of the structures indicates a SE from both the electrical field and magnetical field in some narrow ranges
Micro-CT supporting structural analysis and modelling of ropes made of natural fibers
This paper describes the modelling of the structure and mechanical parameters of rope components made of natural
fibers. Modern X-ray micro-tomography (Micro-CT) was employed to measure the parameters of the internal structure
of the multi-component yarns making up rope and utilized as a basic model of twisted rope. The results allowed
calculation of the tensions generated in the component yarns and detection of the unevenness of the filling of the
component yarns by fibers, which was clearly visible in cross-section. The unevenness of twist measured as a function of
distance from the center of the yarn was also detected. The unevenness of fiber distribution in the twisted element
decreased its intensity, starting from the surface of the yarn and going deeper into the structure. Migration of the fibers in
the frame of the circumference of the component yarns was associated with the mutual slide of single fibers
Fingertip skin models for analysis of the haptic perception of textiles
This paper presents finite element models of the fingertip skin which have been created to simulate the contact of textile objects with the skin to gain a better understanding of the perception of textiles through the skin, the so-called hand of textiles. Many objective and subjective techniques have already been developed for analysing the hand of textiles; however, none of them provide exact overall information concerning the sensation of textiles through the skin. As the human skin is a complex heterogeneous hyperelastic body composed of many particles, some simplifications had to be made at the early stage of building the models; however, their utilitarian value was maintained. The models relate only to mechanical loading of the skin. They predict a low deformation of the fingertip skin under the pressure of virtual heterogeneous material: acrylic, coarse wool, and steel
Analysis of hybrid woven fabrics with shape memory alloys wires embedded
Until recently, Shape Memory Alloys (SMAs) were predominantly developed for applications in the biomedical and engineering industry, and only a limited number of applications in textiles are known. Fabrics made of natural fibres (e. g. cotton, flax and their mixtures) present many advantages, such as wearing comfort, but they are subject to creasing. The aim of this study was to investigate the possibility of compensating for this disadvantage by using SMAs to create aesthetic low crease flax/cotton fabrics. Body Temperature SMAs (BT SMA) that regain their (straight) form when they are subject to human body temperature were used for this purpose. Clothing and bed sheeting are potential applications of these hybrid structures, which become wrinkle-free when they are exposed to the heat of the body, a hair dryer or that generated by an electrical current. The materials selected to achieve this purpose were the following: (1) textile yarns (e. g. single cotton or flax/cotton yarns, two-fold flax yarns and two types of loop fancy yarns) and (2) BT SMA wires of 300 mu m diameter. A power weaving loom and a hand-weaving shuttle loom were used to embed the SMA wires, and four types of hybrid fabrics were produced. The thickness, wrinkle recovery, dimensional stability as well as the cohesion of the SMA wires in the woven fabric were tested. All the tests were performed before and after a washing cycle for both the hybrid and reference fabrics. An increase in thickness was noticed after washing, and the recovery time after crushing varied according to the type of fabric. The slippage of SMA wires from the fabrics was noticed for all the samples, which was dependent on the type of yarns used, their linear density and the weaving process
Lead Ion Uptake By Sodium Alginate And Calcium Alginate Film: A Comparison Study
Abstract. Lead ion (Pb(II)) uptake from aqueous solution by two different alginate compounds was investigated. Sodium alginate (Na-Alg) and calcium alginate (Ca-Alg) films were successfully fabricated from the commercially available sodium alginate powder. The Pb(II) uptake performance by Na-Alg and CaAlg films was evaluated against time in a 10 mM Pb(II) solution's batch sorption system. Ca-Alg film was consistently showing a better Pb(II) uptake performance as compared to Na-Alg film within the investigated duration. Further evaluation on Ca-Alg film was carried out at lower Pb(II) concentrations, i.e. 1 mM and 0.1 mM, the Ca-Alg film showed the best performance in 0.1 mM Pb(II) solution at a uptake rate higher than 98%. The Pb(II) uptake performance of Ca-Alg film was also compared with that of the conventionally fabricated Ca-Alg beads. This result indicates that with the same amount of Ca-Alg used, the film shows approximately three time better Pb(II) uptake performance compared to the beads. The results reported herein indicates that Ca-Alg compound is an effective and efficient biosorbent, furthermore the Pb(II) uptake performance is influenced by the sample fabrication method as well, i.e. film versus bead, which contributed to the overall surface area
The clinical usefulness of biochemical (free β-hCG, PAPP-A) and ultrasound (nuchal translucency) parameters in prenatal screening of trisomy 21 in the first trimester of pregnancy
Objectives: The aim of the study was to analyze the correlation of multiples of the normal median of PAPP-A, free β-hCG levels and nuchal translucency values in prenatal, first trimester screening of trisomy 21 in pregnant women. Material and methods: 251 pregnant women underwent antenatal screening at 11–13+6 weeks of pregnancy which was composed of the measurement of free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein (PAPP-A) levels in the maternal serum and an ultrasound assessment of nuchal translucency (NT). The pregnant women with a high risk of trisomy 21 (≥ 1:300) were given amniocentesis to verify fetal defects. There were 217 cases of normal fetal karyotype and 34 cases of trisomy 21. PAPP-A, β-hCGMoM and NT values were analyzed for the predefined ranges. Results: 85% cases of trisomy 21 had elevated free β-hCGMoM ( > 1.5) and only 53% of these had a PAPP-AMoM result below 0.5 (p < 0.05). Analysis of NT in selected ranges of β-hCG ( > 1.5) and PAPP-AMoM ( < 0.05), which are typical for Down Syndrome values, showed that not all fetuses with Down Syndrome presented with an increased NT. Respectively 44.15% and 26.5% of fetuses presented with increased NT. Characteristic for trisomy 21, a correlation with all 1st trimester screening tests’ parameters occurred in only 23.5% of cases. In 53% of cases the results were atypical. Conclusions: The PAPP-A and β-hCG values in the selected MoM ranges did not shown a correlation to the NT measurement, therefore they are independent factors in the diagnosis of trisomy 21. Simultaneous biochemical and ultrasound testing is an indispensable condition for prenatal diagnosis of trisomy 21 in the 1st trimester of pregnancy.
The trans fatty acid elaidate affects the global DNA methylation profile of cultured cells and in vivo
BACKGROUND: The deleterious effects of dietary trans fatty acids (tFAs) on human health are well documented. Although significantly reduced or banned in various countries, tFAs may trigger long-term responses that would represent a valid human health concern, particularly if tFAs alter the epigenome. METHODS: Based on these considerations, we asked whether the tFA elaidic acid (EA; tC18:1) has any effects on global DNA methylation and the transcriptome in cultured human THP-1 monocytes, and whether the progeny of EA-supplemented dams during either pregnancy or lactation in mice (n = 20 per group) show any epigenetic change after exposure. RESULTS: EA induced a biphasic effect on global DNA methylation in THP-1 cells, i.e. hypermethylation in the 1–50 μM concentration range, followed by hypomethylation up to the 200 μM dose. On the other hand, the cis isomer oleic acid (OA), a fatty acid with documented beneficial effects on human health, exerted a distinct response, i.e. its effects were weaker and only partially overlapping with EA’s. The maximal differential response between EA and OA was observed at the 50 μM dose. Array expression data revealed that EA induced a pro-inflammatory and adipogenic transcriptional profile compared with OA, although with modest effects on selected (n = 9) gene promoter methylation. In mice, maternal EA supplementation in utero or via the breastmilk induced global adipose tissue DNA hypermethylation in the progeny, that was detectable postnatally at the age of 3 months. CONCLUSION: We document that global DNA hypermethylation is a specific and consistent response to EA in cell culture and in mice, and that EA may exert long-term effects on the epigenome following maternal exposure. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12944-016-0243-2) contains supplementary material, which is available to authorized users
Maternal factors, ultrasound and placental function parameters in early pregnancy as predictors of birth weight in low-risk populations and among patients with pre-gestational diabetes
Objectives: The aim of our work was to assess the usefulness of maternal factors, ultrasound and placental function parameters during early pregnancy as predictors of birth weight in populations of healthy pregnant women and women suffering from pregestational diabetes.
Material and methods: A study group comprised 97 healthy women and 160 women with pregestational diabetes (PGDM, type 1), all in singleton pregnancy. Ultrasound examination was performed between weeks 11 and 14, and in weeks 20 and 30 of gestation, based on recommendations of the Polish Society of Gynecologists and Obstetricians, Ultrasonography Division. We also checked uterine artery blood flow parameters. During the first trimester consultation, all patients were surveyed and the following data were collected: age, BMI, reproductive history, comorbidities and smoking. We also collected blood samples and assessed PlGF, PAPP-A, and BhCG levels.
Results: Our study showed that newborn birth weight negatively correlated with mother’s age, her diastolic blood pressure, PI of her uterine arteries and BhCG protein levels. Moreover, birth weight directly correlated with PlGF and PAPPA-A protein levels, and maternal early-pregnancy BMI.
Conclusions: LGA diagnosis in the first trimester of pregnancy allows for selection and modification of some risk factors and closer monitoring of endangered fetuses throughout the pregnancy, with emphasis on the perinatal period. Parameters with confirmed usefulness in the prediction of birth weight in the first trimester included: maternal age, BMI, blood pressure, PAPP-A, BhCG and PlGF levels, fetal CRL and uterine artery PI
Does intraoperative application of TachoSil reduce the number of lymphoceles after pelvic lymphadenectomy?
Objectives: The degree of lymphoceles prevention was assessed using collagen patches coated with human coagulation factors (TachoSil, Nycomed International Management GmbH, Zurich, Switzerland). The study enrolled 50 consecutive patients with endometrial and cervical cancer stages IB to II who had undergone open hysterectomy and pelvic lymphadenectomy (PL). In addition, the drainage volumes of 22 patients with hypertension were compared to that of the rest of the study population. Furthermore, occurrence of lymphocele in patients with endometrial and cervical cancer were compared after completion of adjuvant treatment.
Material and methods: Patients were simultaneously randomized in two groups: as a control (side without TachoSil applied) and study group (side with TachoSil applied). All surgical parameters were collected, and patients underwent ultrasound examination on postoperative days 1, 6, and 30, and at the end of treatment.
Results: The TachoSil Group showed a lower drainage volume, 30 days after surgery, while outflow of fluid occurred in 11 (22%) of all TachoSil Group cases and 22 (44%) of all control group cases. Furthermore, two patients in the control group had symptomatic lymphocele, while the same number of cases was observed in the TachoSil Group. However, the TachoSil Group demonstrated a decreased tendency to lymphocele occurrence after the end of adjuvant therapy. Here, patients with the collagen patch developed lymphocele in 12% of all cases, as opposed to 18% without TachoSil.
Conclusions: TachoSil is a useful support treatment option for reducing drainage volume and preventing lymphocele development after lymphadenectomy
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