Recovery responses in the bodies of rats following irradiation with microwaves (2400 MHz)

During microwave irradiation (SHF-field, 2400 Mc/s) of rats in the range of capacity density of from 100 mW/cm2 to 800 mW/cm2 the function of regenerative effect and the time interval between the irradiation cycles (power densityconst) approximates the logistic one, whereas that of the power density and the time interval between the irradiation cycles (regeneration level = const) approximates the linear one.     

532 nm波段连续激光对视网膜和脉络膜生物学作用的观察

目的：探讨532nm波段激光不同光剂量参数对眼底组织的损伤特点及损伤阈值。方法：以新西兰兔为实验对象,532nm连续激光照射眼底,眼底光斑直径1．5mm～2．5mm,功率密度从500mW／cm^2：～2400mW／cm^2,照射时间100s～300s,每组参数10个光斑。在照射后1h和24h进行眼底观察和荧光眼底造影,计算三种照射时间情况下视网膜的损伤阈值。结果：在照射后第1h,功率密度为902mW／crn2,照射时间300s开始出现视网膜灰色改变,病灶范围接近照光面积,在24h后颜色微加重。随着照光剂量的增加,在功率密度达1479mW／cm2,照射时间300s,照射后1h出现视网膜灰白色改变,在24h后出现脉络膜出血;而且随着照光剂量的增加,病灶范围扩大越明显。出血量越多。随着照光剂量的减少,当功率密度1003mW／cm^2,照射时间200s时,在照光后1h眼底没有改变,24h出现视网膜灰白色改变,面积接近照光面积;光剂量降低到1002mW／cm^2,照射时间100s时,在24h才出现视网膜灰白色改变,变化的视网膜范围小于照光面积。统计学计算在照射时间为300s、200s和100s,照光后1h视网膜损伤阈值分别为911．15628mW／cm^2,1167．64770mW／cm^2,1513．89832mW／cm^2,24h视网膜损伤阈值分别为827．09664mW／cm^2。1003．73143mW／cm^2,1154．17863mW／cm^2。结论：在光线照射后24h之内,视网膜损伤是一个逐渐增强的过程。从视网膜没有明显可见改变到视网膜出现灰白色可见损伤,变化范围从小于照光面积到接近照光面积,甚至超过照光面积,并出现脉络膜出血,出血面积随着照光剂量的增加而范围变大。相同能量密度的光剂量对视网膜损伤轻重取决于激光的功率密度。     

Inhibitory action of microwave radiation on gamma-glutamyl transpeptidase activity in liver of rats treated with hydrocortisone

The influence of microwave irradiation on the activity of gamma-glutamyl transpeptidase (GGT) induced by hydrocortisone (HC) in the liver of rats was investigated. Animals were subjected to microwave irradiation (frequency 53.57 GHz, power density 10 mW/cm2 and 1 mW/cm2) during and after hydrocortisone (HC) treatment (20 mg/kg for 60 days). The results indicate that microwave radiation may block an inducible effect of HC on GGT activity in the liver of rats. This effect depends on the power density of millimetre microwaves.     

578.2 nm激光照射对兔视网膜的损伤效应研究

研究578.2 nm激光照射对兔视网膜的作用特点,以新西兰白兔5只10眼为实验对象,铜蒸汽激光(578.2 nm)通过裂隙灯照射兔视网膜后极部,照射时间为100 s,光斑直径为2 mm,照射剂量分别为60 J/cm2、80 J/cm2、100 J/cm2、120 J/cm2、160 J/cm2、200 J/cm2,每组4个光斑。照后1 h及24 h进行眼底照相及光镜观察。照光后可见,随激光功率密度的增加,兔视网膜的损伤也逐渐加重,并且照后24 h的损伤要重于照后1h。80 J/cm2和60 J/cm2在照后1 h和24 h均未发现明显改变。578.2 nm激光照射白兔后的主要病理学改变位于脉络膜。因此,以578.2 nm激光作为光动力治疗眼底疾病的光源时,照射剂量不宜超过80 J/cm2。     

Stimulation of Burn Wound Healing in Rats by Nanosecond Repetitive Pulsed Microwave Radiation

Biology Bulletin - The effect of nanosecond repetitive pulsed microwave radiation (RPMR, 10 GHz, 100 ns pulse duration, 8 Hz pulse repetition rate, 140 and 1500 W/cm2 peak power flux density...     

Effects of injurying and restoring the body of rats with microwave (2400 MHz) irradiation]

In experiments on 2072 rats the thresholds of power density (PD) and the duration of microwave irradiation were obtained with the effect of destruction not more than 0.1%. The speed ratio of formation processes of destruction and regeneration depends on power density of microwave radiation and interpolates the exponential function. Previously obtained (from experiments on mice) and now published data allow the eifference to be established between mice and rats as species. Mice are more sensitive from the standpoint of time of achieving equal effects of destruction, half and full period of regeneration, the speed ratio between destruction and regeneration depending on PD of microwave radiation.     

Advanced high-power pulsed light device to decontaminate food from pathogens: effects on Salmonella typhimurium viability in vitro

AIMS: The aim of this study was to construct an advanced high-power pulsed light device for decontamination of food matrix and to evaluate its antibacterial efficiency. Key parameters of constructed device-emitted light spectrum, pulse duration, pulse power density, frequency of pulses, dependence of emitted spectrum on input voltage, irradiation homogenicity, possible thermal effects as well as antimicrobial efficiency were evaluated. METHODS AND RESULTS: Antimicrobial efficiency of high-power pulsed light technique was demonstrated and evaluated by two independent methods - spread plate and Miles-Misra method. Viability of Salmonella typhimurium as function of a given light dose (number of pulses) and pulse frequency was examined. According to the data obtained, viability of Salmonella typhimurium reduced by 7 log order after 100 light pulses with power density 133 W cm(-2). In addition, data indicate, that the pulse frequency did not influence the outcome of pathogen inactivation in the region 1-5 Hz. Moreover, no hyperthermic effect was detected during irradiation even after 500 pulses on all shelves with different distance from light source and subsequently different pulse power density (0-252 W cm(-2)). CONCLUSION: Newly constructed high-power pulsed light technique is effective nonthermal tool for inactivation of Salmonella typhimurium even by 7 log order in vitro. SIGNIFICANCE AND IMPACT OF THE STUDY: Novel advanced high-power pulsed light device can be a useful tool for development of nonthermal food decontamination technologies.     

Thermoregulatory adjustments in squirrel monkeys exposed to microwaves at high power densities

The present study was undertaken to investigate the thermal adjustments of squirrel monkeys exposed in a cold environment to relatively high energy levels of microwave fields. The animals (Saimiri sciureus) were equilibrated for 90 min to a cool environment (Ta = 20 degrees C) to elevate metabolic heat production (M). They were then exposed for brief (10-min) or long (30-min) periods to 2,450-MHz continuous-wave microwaves. Power densities (MPD) were 10, 14, 19, and 25 mW/cm2 during brief exposures and 30, 35, 40, and 45 mW/cm2 during long exposures (rate of energy absorption: SAR = 0.15 [W/kg]/[mW/cm2]). Individual exposures were separated by enough time to allow physiological variables to return to baseline levels. The results confirm that each microwave exposure induced a rapid decrease in M. In a 20 degree C environment, the power density of a 10-min exposure required to lower M to approximate the resting level was 35 mW/cm2 (SAR = 5.3 W/kg). During the long exposures, 20 min was needed to decrease M to its lowest level. Cessation of irradiation was associated with persistence of low levels of M for periods that depended on the power density of the preceding microwave exposure. Vasodilation, as indexed by changes in local skin temperature, occurred at a high rate of energy absorption (SAR = 4.5 W/kg) and was sufficient to prevent a dramatic increase in storage of thermal energy by the body; vasoconstriction was reinstated after termination of irradiation. Patterns of thermophysiological responses confirm the influence both of peripheral and of internal inputs to thermoregulation in squirrel monkeys exposed to microwaves in a cool environment.     

Ethanol-induced hypothermia and ethanol consumption in the rat are affected by low-level microwave irradiation

Microwave irradiation of rats by circularly polarized, 2,450-MHz, pulsed waves (2-μs pulses; 500 pps) was performed in waveguides to determine effects on ethanol-induced hypothermia and on ethanol consumption. Rats injected intraperitoneally with ethanol (3 g/kg in a 25% v/v water solution) immediately after 45 min of microwave irradiation exhibited attenuation of the initial rate of fall in body temperature, which was elicited by the ethanol, but exhibited no significant difference in maximal hypothermia as compared with that of sham-irradiated rats. Microwave irradiation did not affect the consumption of a 10% sucrose (w/v) solution by water-deprived rats. However, it enhanced the consumption of a solution of 10% sucrose (w/v) + 15% ethanol (v/v) by water-deprived animals. These results were obtained at a specific absorption rate (SAR) of 0.6 W/kg, which rate of energy dosing would require a power density of 3–6 mW/cm² if exposure of the animals had occurred to a 12-cm plane wave.     

Pulse flows of neuronal populations of the cerebral cortex exposed to low intensity microwaves

Pulse flows of populations of cortical neurons in rabbit were investigated prior to, during, and after 1-min microwave irradiation (wavelength 37.5 cm, power density 0.5-1 mW/cm2). It was found that irradiation caused rearrangements in burst activity, which manifested themselves predominantly as changes in the number of spikes forming the bursts. The direction of shifts depended on the time threshold levels of revelation of bursts. These effects took place during microwave irradiation and after its cessation.     

Effect of microwave electromagnetic field on skeletal muscle fibre activity

The aim of the present study was to investigate the influence of microwave irradiation on fatiguing activity of isolated frog skeletal muscle fibres. The changes in the electrical and mechanical activity were used as criteria for the exposure effects. Repetitive suprathreshold stimulation with interstimulus interval of 200 ms for 3 min was applied. Intracellular (ICAP) and extracellular (ECAP) action potentials and twitch contractions (Tw) of muscle fibres after 1 hour microwave exposure (2.45 GHz, 20 mW/cm( 2) power density) were compared with those recorded after one hour sham exposure (control). The duration of uninterrupted activity in the trial (endurance time; ET) was not significantly affected by microwave field exposure. After microwave irradiation, the ICAP amplitude was higher, the rising time was shorter, and the resting membrane potential was more negative compared to controls. There was a slower rate of parameters changes during ET in potentials obtained from irradiated fibres. Microwave exposure increased the propagation velocity of excitation, the ECAP and Tw amplitudes, as well as shortened their time parameters. We concluded that a 2.45 GHz microwave field possesses a stimulating effect on muscle fibre activity, which is in part due to its specific, non-thermal properties. The microwave induced-changes in muscle fibre activity may reduce development of skeletal muscle fatigue.     

The efficiency and direction of thymus changes after whole-body exposure of mice to the weak electromagnetic field are determined by the initial status of the thymus

The work presents results of the experimental study on thymus changes developing after whole-body exposure of mice to ultralow power pulse-modulated electromagnetic field (carrying frequency 2.39 GHz, modulating pulses with frequency 4 Hz, duration of impulses 0.025 sec, average power density 60 mW/cm2, absorbed dose 0.086 J/g or 0.172 J/g). It was shown that a percent of the microwave induced increase or decrease of thymus mass and the number of cells in the organ (y) are determined by the initial mass or number of cells in thymus accordingly to equation of linear regression: (yx = 215-2.25x, where x is the thymus mass of control animals (in a range 31-63 mg) and (yx = 178.6-41x, where x is the initial number of cells in thymus (in a range 0.6 x 10(8)-2.6 x 10(8)) reduced by a factor of 10(8).     

Karyometric observations of WISH cell cultures irradiated with 3 GHz microwaves.

WISH cell cultures 24 hours after passage were irradiated with 3 GHz microwaves (10 cm) at far field conditions in free space (anechoic chamber) for 30 minutes, at field power density 5 or 20 mW/cm2. Within 1,24 and 48 hours of the exposure to microwave fields the volumes of nuclei and nucleoli were measured with the use of a micrometer, and logvolumes and nucleo-nucleolar ratios were calculated. Under the applied irradiation conditions the culture medium temperature did not exceed 37 degrees C. In cultures irradiated at field power density 20 mW/cm2 increased number of cells with small nuclei and enlarged nucleoli was noted within 1 hour of the exposure. Within 24 and 48 hours after irradiation the nucleolar volume showed a slight decrease, whereas the nuclear volume increased. In cultures irradiated at field power density 5 mW/cm2 increased numbers of cells with enlarged nuclei and nucleoli were found. Analysis of the distribution curves of nuclear and nucleolar volumes suggests that non-thermal power densities of microwaves stimulate the metabolism of cell cultures. However, at higher power densities (20 mW/cm2) the stimulation phase is preceded by a period of reduced viability of cell cultures.     

Operant control of convective cooling and microwave irradiation by the squirrel monkey

Adult male squirrel monkeys (Saimiri sciureus) were individually chair-restrained in an air-conditioned Styrofoam box in the far field of a horn antenna. Each monkey first received extensive training to regulate the temperature of the air circulating through the box by selecting between 10 and 50 degrees C air source temperatures. Then, to investigate the ability of the animals to utilize microwaves as a source of thermalizing energy, 2450-MHz continuous wave microwaves accompanied by thermoneutral (30 degrees C) air were substituted for the 50 degrees C air. Irradiation at each of three power densities was made available, ie, at 20, 25, and 30 mW/cm2 [SAR = 0.15 (W/kg)/(mW/cm2)]. The percentage of time that the monkeys selected microwave irradiation paired with thermoneutral air averaged 90% at 20 and at 25 mW/cm2. The mean percentage declined reliably (p less than 0.001) to 81% at 30 mW/cm2, confirming the monkey's ability to utilize microwave irradiation as a source of thermal energy during the course of behavioral thermoregulation. All animals readily made the warm-air to microwave-field transition, regulating rectal temperature with precision by sequentially selecting 10 degrees C air, then microwave irradiation accompanied by 30 degrees C air. Although the selection of cooler air resulted in a slight reduction of skin temperatures, normal rectal temperature was maintained. The results indicate that the squirrel monkey can utilize a microwave source in conjunction with convective cooling to regulate body temperature behaviorally.     

Serum enzymes in hemorrhaged Japanese quail after microwave irradiation during embryogeny

1. Japanese quail eggs were exposed to 2.45 GHz continuous wave microwave radiation at an incident power density of 5 mW/cm2 and a specific absorption rate of 4.03 mW/g during the first 12 days of embryogeny. 2. After hatching, serum biochemical changes in response to hemorrhagic stress were measured following a hemorrhage of 30% of the calculated total blood volume. 3. Lactate dehydrogenase, beta-glucuronidase, acid phosphatase, glucose and protein were not affected by microwave irradiation during embryogeny either before or after hemorrhage. 4. Microwave irradiation in ovo affected the response of serum glutamic oxaloacetic transaminase activity to hemorrhagic stress in Japanese quail.     

The effect of ultrahigh-frequency electromagnetic radiation on learning and memory processes]

Low-intensity electromagnetic field (12.6 cm, 2375 MHz, power density 1 mW/cm2) produced retrograde amnesia in the rat passive avoidance test. No effect was registered of microwave irradiation on the open field behavior and the pain sensitivity. Functional activity of the m-cholinergic receptors decreased, but their number increased in the brain cortex. It is suggested that cholinergic system plays an important role in the effects of electromagnetic field on memory processes.     

Combination of pharmacological analgesics and microwave irradiation of an acupuncture point for suppression of visceral pain in mice: Role of the opioid and serotonergic cerebral systems

We studied suppression of pain-related reactions induced in mice by i.p. injection of 0.08 ml of a 2% solution of acetic acid using pharmacological analgesics (analgin and tramadol) combined with low-intensity microwave irradiation of an acupuncture point (AP) E-36 (frequency 30 to 300 GHz and power rate density 3·10⁻⁹ W/cm²). The respective effects were also observed under conditions of suppression of the functions of opioid and serotonergic cerebral systems using injections of, respectively, naloxone and DL-p-chlorophenylalanine (p-CPA). We found that antinociceptive effects provided by analgesics used in a 50% mean single dose in the combination with microwave irradiation of the AP were significantly more intense than those induced by isolated injection of analgesics used in both 50% and full mean single doses and isolated microwave irradiation of the AP E-36. After injections of naloxone, analgesic effects caused by the combined action of analgin and microwave irradiation of the AP were considerably smaller. At the same time, after injection of p-CPA, analgesic effects, provided by the combination of injection of pharmacological agents and microwave irradiation of the AP, weakened in the case of use of both analgesics. This was manifested in a significant increase in the total duration of pain-related behavioral reactions. Therefore, the studied analgesic effects observed in the examined animal groups are realized due to the involvement of the opioid and serotonergic cerebral systems. Neirofiziologiya/Neurophysiology, Vol. 39, No. 6, pp. 468–477, November–December, 2007.     

Stimulation of production of tumor necrosis factor by murine macrophages when exposed in vio and in vitro to weak electromagnetic waves in the centimeter range

Whole-body microwave sinusoidal irradiation of male NMRI mice, exposure of macrophages in vitro, and preliminary irradiation of culture medium with 8.15-18 GHz (1 Hz within) at a power density of 1 microW/cm2 caused a significant enhancement of tumor necrosis factor production in peritoneal macrophages. The role of microwaves as a factor interfering with the process of cell immunity is discussed.     

Response of Japanese quail to hemorrhagic stress after exposure to microwave radiation during embryogeny

Coturnix coturnix japonica eggs were exposed to 2.45 GHz continuous wave microwave radiation at an incident power density of 5 mW/cm2 (SAR = 4 mW/g) during the first 12 days of embryogeny. After hatching, hematologic changes in response to an acute hemorrhage were measured in exposed and nonexposed (control) juveniles and adults of both sexes. Reticulocyte numbers and percentages were depressed below control numbers at 24 hr postphlebotomy in exposed adult females. Lymphocyte numbers were depressed below control levels at 24 hr postphlebotomy in exposed juvenile and adult males. At 72 hr heterophil numbers were depressed in exposed juvenile and adult males. These data suggest that microwave irradiation during embryogeny affects the ability of Japanese quail to recover from an acute and voluminous hemorrhage and that these radiation effects are small.     

Output power variations in a plasma relativistic microwave amplifier during a 500-ns relativistic electron beam current pulse

A relativistic plasma microwave amplifier with a gain of about 30 dB and an output power of about 60–100 MW in the frequency range from 2.4 to 3.2 GHz is studied experimentally. The total duration of the output microwave pulse is equal to the duration of the current pulse of the driving relativistic electron beam (500 ns); however, the maximum output power is observed only within 200 ns. It is shown that variations in the output microwave power during the current pulse of the annular relativistic electron beam are caused by variations in the beam radius and thickness. Analysis of the experimental data and results of numerical simulations show that the thickness of the electron beam is determined by the density of the cathode emission current.