In this study, electromagnetic shielding effectiveness of some weft‐knitted structures is investigated. For this purpose, weft‐knitted structures are produced using copper wire/cotton incorporated yarns. Conductive yarns are produced by yarn‐folding machine. Four knitted constructions (plain knitting, weft in‐laid plain knitting, 1X1 rib, and weft in‐laid 1X1 rib) are formed into knitted structures with conductive yarns by using 7G flat knitting machine. Electromagnetic shielding values of test samples are determined by a coaxial test fixture relating to ASTM D4935 test standards. Measurements are made in the frequency range of 27 MHz–3 GHz. The effect of conductive content, stitch density and fabric construction parameters are investigated considering the electromagnetic shielding performance of weft‐knitted structures. Test results show that weft‐knitted structures investigated in this study have 10–40 dB shielding effectiveness under the frequency of 500 MHz.

The aim of this study was to investigate the effects of a 2450 MHz electromagnetic field (EMF) (wireless internet frequency) on the growth and development of female Wistar rats. The study was conducted on three groups of rats. The prenatal and postnatal groups were exposed to EMF 1 h/day beginning from intrauterine and postnatal periods, respectively. The third group was the sham-exposed group. Growth, nutrition and vaginal opening (VO) were regularly monitored. Serum and tissue specimens were collected at puberty. Histological examinations, total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) measurements in ovary and brain tissues and also immunohistochemical staining of the hypothalamus were performed besides the determination of serum FSH, LH, E2 and IGF-1 values. Birth masses of the groups were similar (p > 0.05). Mass gain per day was significantly lower and the puberty was significantly later in the prenatal group. Brain and ovary TOS and OSI values in the prenatal group were significantly increased (p < 0.05) compared to the control group. Serum LH levels of the prenatal and postnatal groups were increased, although serum FSH, and E2 values did not differ among the groups (p > 0.05). Histological examinations of the specimens revealed no statistically significant difference between the groups (p > 0.05). Exposure to 2450 MHz EMF, particularly in the prenatal period, resulted in postnatal growth restriction and delayed puberty in female Wistar rats. Increased TOS and OSI values in the brain and ovary tissues can be interpreted as a sign of chronic stress induced by EMF. This is the first longitudinal study which investigates the effects of EMF induced by wireless internet on pubertal development beside growth.

The heart is a contractile organ that can generate its own rhythm. The contraction, or the rhythm, of the heart may be influenced by electromagnetic field (EMF) exposure, because of the heart's excitability characteristic. In previous studies, different methods have been used to study the possible effects of an extremely low frequency electromagnetic field (ELF-EMF) on the heart. But the studies’ designs were not similar, and the results were also different. Recent studies have shown some evidence that short-term EMF exposure can influence the heart more than long-term exposure. This study investigated how the heart is affected in the first EMF exposure. In a simulation of the daily exposure of humans to a power frequency, Wistar albino rats were used. By utilizing the Helmholtz-coil set, we obtained a 50-Hz, 1-μT EMF and examined rat heart activity during short-term EMF exposure. No effect was observed under this exposure condition. The results obtained do not confirm a possible mechanism in the electrical activity of the rat heart model.