Absence of corneal endothelium injury in non‐human primates treated with and without ophthalmologic drugs and exposed to 2.8 GHz pulsed microwaves

Microwave‐induced corneal endothelial damage was reported to have a low threshold (2.6 W/kg), and vasoactive ophthalmologic medications lowered the threshold by a factor of 10–0.26 W/kg. In an attempt to confirm these observations, four adult male Rhesus monkeys (Macaca mulatta) under propofol anesthesia were exposed to pulsed microwaves in the far field of a 2.8 GHz signal (1.43 ± 0.06 µs pulse width, 34 Hz pulse repetition frequency, 13.0 mW/cm² spatial and temporal average, and 464 W/cm² spatial and temporal peak (291 W/cm² square wave equivalent) power densities). Corneal‐specific absorption rate was 5.07 W/kg (0.39 W/kg/mW/cm²). The exposure resulted in a 1.0–1.2 °C increase in eyelid temperature. In Experiment I, exposures were 4 h/day, 3 days/week for 3 weeks (nine exposures and 36 h total). In Experiment II, these subjects were pretreated with 0.5% Timolol maleate and 0.005% Xalatan® followed by 3 or 7 4‐h pulsed microwave exposures. Under ketamine–xylazine anesthesia, a non‐contact specular microscope was used to obtain corneal endothelium images, corneal endothelial cell density, and pachymetry at the center and four peripheral areas of the cornea. Ophthalmologic measurements were done before and 7, 30, 90, and 180 days after exposures. Pulsed microwave exposure did not cause alterations in corneal endothelial cell density and corneal thickness with or without ophthalmologic drugs. Therefore, previously reported changes in the cornea exposed to pulsed microwaves were not confirmed at exposure levels that are more than an order of magnitude higher. Bioelectromagnetics 31:324–333, 2010. Published 2010 Wiley‐Liss, Inc.     

Ultrastructural study of collagen fibrils,proteoglycans and lamellae of the cornea treated with iontophoresis – UVA cross-linking and hypotonic riboflavin solution

To investigate the effects of iontophoresis–ultraviolet A (UVA) cross-linking (CXL) with hypotonic riboflavin solution on the ultrastructural changes in the lamellae, collagen fibrils (CFs), and proteoglycans (PGs) in the central and peripheral stroma of the human corneal buttons. The iontophoresis method was used for the trans-epithelial application of hypotonic riboflavin in ex vivo corneal culture for 5 min. The corneas were irradiated using three methods: Group 1 (G1), a UVA irradiance of 3 mW/cm² for 30 min; Group 2 (G2), a UVA irradiance of 10 mW/cm² for 9 min; Group 3 (G3), without UVA irradiation. Three untreated corneas were used as controls (G0). After the CXL procedure, the corneas were processed for electron microscopy. The CF diameter and PGs in each sample were analyzed using the iTEM program. The keratocyte organelles and stromal architecture in the peripheral cornea were better preserved than those in the central cornea. In G1 and G2, the mean CF diameter in the peripheral cornea was significantly higher than that in the central cornea. In G3, the CF diameter in the central cornea was significantly larger than that in the peripheral cornea. Furthermore, differences in PG area size were observed between the central and peripheral corneas in all groups. Riboflavin + UVA application at 3 mW/cm² for 30 min and 10 mW/cm² for 9 min was a suitable method of CXL; however, 3 mW/cm² for 30 min improved the organization and size of the collagen fibrils. CXL treatment applied at the periphery was more effective than that applied at the center.     

Two-photon collagen crosslinking in ex vivo human corneal lenticules induced by near-infrared femtosecond laser

Myopia and keratoconus have become common corneal diseases that threaten the quality of human vision, and keratoconus is one of the most common indications for corneal transplantation worldwide. Collagen crosslinking (CXL) using riboflavin and ultraviolet A (UVA) light is an effective approach for treating ophthalmic disorders and has been shown clinically not only to arrest further progression of keratoconus but also to improve refractive power for cornea. However, CXL surgery irradiated by UVA has various potential risks such as surface damage and endothelial cell damage. Here, near-infrared femtosecond laser-based two-photon CXL was first applied to ex vivo human corneal stroma, operating at low photon energy with high precision and stability. After two-photon CXL, the corneal stiffness can be enhanced by 300% without significantly reducing corneal transparency. These findings illustrate the optimized direction that depositing high pulses energy in corneal focal volume (not exceeding damage threshold), and pave the way to 3D CXL of in vivo human cornea with higher safety, precision, and efficacy.     

Ultrastructural study of collagen fibrils,proteoglycans and lamellae of the cornea treated with iontophoresis – UVA cross-linking and hypotonic riboflavin solution

To investigate the effects of iontophoresis–ultraviolet A (UVA) cross-linking (CXL) with hypotonic riboflavin solution on the ultrastructural changes in the lamellae, collagen fibrils (CFs), and proteoglycans (PGs) in the central and peripheral stroma of the human corneal buttons. The iontophoresis method was used for the trans-epithelial application of hypotonic riboflavin in ex vivo corneal culture for 5 min. The corneas were irradiated using three methods: Group 1 (G1), a UVA irradiance of 3 mW/cm² for 30 min; Group 2 (G2), a UVA irradiance of 10 mW/cm² for 9 min; Group 3 (G3), without UVA irradiation. Three untreated corneas were used as controls (G0). After the CXL procedure, the corneas were processed for electron microscopy. The CF diameter and PGs in each sample were analyzed using the iTEM program. The keratocyte organelles and stromal architecture in the peripheral cornea were better preserved than those in the central cornea. In G1 and G2, the mean CF diameter in the peripheral cornea was significantly higher than that in the central cornea. In G3, the CF diameter in the central cornea was significantly larger than that in the peripheral cornea. Furthermore, differences in PG area size were observed between the central and peripheral corneas in all groups. Riboflavin + UVA application at 3 mW/cm² for 30 min and 10 mW/cm² for 9 min was a suitable method of CXL; however, 3 mW/cm² for 30 min improved the organization and size of the collagen fibrils. CXL treatment applied at the periphery was more effective than that applied at the center.Keyword: Collagen fibrils, Proteoglycans, Cornea, Iontophoresis, Ultraviolet A     

Accelerated development of spontaneous and benzopyrene-induced skin cancer in mice exposed to 2450-MHz microwave radiation

C₃H/HeA mice with high incidence of spontaneous breast cancer and Balb/c mice treated with 3,4-benzopyrene (BP) (by painting of the skin resulting in the development of skin cancer) were irradiated with 2,450-MHz microwaves (MW) in an anechoic chamber at 5 or 15 mW/cm² (2 h daily, 6 sessions per week). C₃H/HeA mice were irradiated from the 6th week of life, up to the 12th month of life. Balb/c mice treated with BP were irradiated either prior to (over 1 or 3 months) or simultaneously with BP treatment (over 5 months). The appearance of palpable tumors in C₃H/HeA mice and of skin cancer in BP-treated Balb/c mice was checked every 2 weeks for 12 months. Two additional groups of mice were exposed to chronic stress caused by confinement or to sham-irradiation in an anechoic chamber; these served as controls. Irradiation with MWs at either 5 or 15 mW/cm² for 3 months resulted in a significant lowering of natural antineoplastic resistance (mean number of lung neoplastic colonies was 2.8 ± 1.6 (SD) in controls, 6.1 ± 1.8 in mice exposed at 5 mW/cm² and 10.8 ± 2.1 in those irradiated at 15 mW/cm²) and acceleration of development of BP-induced skin cancer (285 days in controls, 230 days for 5 mW/cm² and 160 days for 15 mW/cm²). Microwave-exposed C₃H/HeA mice developed breast tumors earlier than controls (322 days in controls, 261 days for 5 mW/cm² and 219 days for 15 mW/cm²). A similar acceleration was observed in the development of BP-induced skin cancer in mice exposed simultaneously to BP and MWs (285 days in controls, 220 day for 5 mW/cm² and 121 days for 15 mW/cm²). The acceleration of cancer development in all tested systems and lowering of natural antineoplastic resistance was similar in mice exposed to MW at 5 mW/cm² or to chronic stress caused by confinement but differed significantly from the data obtained on animals exposed at 15 mW/cm², where local thermal effects (“hot” spots) were possible.     

Thresholds of microwave-evoked warmth sensations in human skin

We measured thresholds for microwave-evoked skin sensations of warmth at frequencies of 2.45, 7.5, 10, 35, and 94 GHz. In the same subjects, thresholds of warmth evoked by infrared radiation (IR) were also measured for comparison. Detection thresholds were measured on the skin in the middle of the back in 15 adult male human subjects at all microwave (MW) frequencies and with IR. Long duration (10-s), large area (327-cm²) stimuli were used to minimize any differential effects of temporal or spatial summation. Sensitivity increased monotonically with frequency throughout the range of microwave frequencies tested. The threshold at 94 GHz (4.5 ± 0.6 mW/cm²) was more than an order of magnitude less than at 2.45 GHz (63.1 ± 6.7 mW/cm²), and it was comparable to the threshold for IR (5.34 ± 1.07 mW/cm²). Bioelectromagnetics 18:403–409, 1997. © 1997 Wiley-Liss, Inc.     

Local cryostimulation acutely preserves maximum isometric handgrip strength following fatigue in young women

Several types of cryostimulation have been recently proposed to rapidly lower skin temperature therefore gaining a possible neuro/muscular recovery after strenuous exercise or, more generally, in sports. Local cryostimulation may be a viable and relatively portable tool to obtain physiological benefits in previously-efforted muscular districts. However, cohesive and standardized cryo-exposure protocols are lacking as well as the righteous procedure to efficaciously combine duration, treatments and temperature in relation to desirable effects on muscular strength. In this randomized-controlled study, fifty young women were tested for maximum isometric handgrip strength, before and after exhausting contractions.Following the fatiguing protocol, the intervention group (cryo, n = 25, 24.7 ± 2.5 years, BMI 21.7 ± 1.8 kg/m²) underwent a 6-min local cryostimulation (−160 °C) on the extensor-flexor muscles of the dominant arm, while control-matched peers sat rested in a thermo-neutral room (22 ± 0.5 °C). Handgrip tests were repeated at baseline (T0), after cryostimulation (T1), and 15 min after T1 (T2). Throughout the protocol, the AUC of the strength performance was significantly higher in the cryo- compared to control group (P = 0.006). In particular, following fatigue and cryostimulation, the cryo group preserved higher strength at T1 with respect to controls (26.8 ± 2.8 vs 23.9 ± 2.8 kg, Bonferroni's post-hoc, P < 0.01). Likewise, ventral and dorsal temperature, recorded with a thermal camera, were lower in cryo- than control group (P < 0.0001).In conclusion, a brief session of local cryostimulation may acutely preserve maximal isometric force in young women following a fatiguing protocol. These findings may have implications in orchestrating strategies of district muscular recovery.     

Light scattering studies of supercoiled and nicked DNA

Static and dynamic light scattering measurements were made of solutions of pGem1a plasmids (3730 base pairs) in the relaxed circular (nicked) and supercoiled forms. The static structure factor and the spectrum of decay modes in the autocorrelation function were examined in order to determine the salient differences between the behaviors of nicked DNA and supercoiled DNA. The concentrations studied are within the dilute regime, which is to say that the structure and dynamics of an isolated DNA molecule were probed. Static light scattering measurements yielded estimates for the molecular weight M, second virial coefficient A₂, and radius of gyration R_G. For the nicked DNA, M = (2.8 ± 0.4) × 10⁶g/mol, A₂ = (0.9 ± 0.2) × 10⁻³ mol cm³/g², and R_G = 90 ± 3 nm were obtained. For the supercoiled DNA, M = (2.5 ± 0.4) × 10⁶ g/mol, A₂ = (1.2 ± 0.2) × 10⁻³ mol cm³/g², and R_G = 82 ± 2.5 nm were obtained. The static structure factors for the nicked and supercoiled DNA were found to superpose when they were scaled by the radius of gyration. The intrinsic stiffness of DNA was evident in the static light scattering data. Homodyne intensity autocorrelation functions were collected for both DNAs at several angles, or scattering vectors. At the smallest scattering vectors the probe size was comparable to the longest intramolecular distance, while at the largest scattering vectors the probe size was smaller than the persistence length of the DNA. Values of the self-diffusion coefficients D were obtained from the low-angle data. For the nicked DNA, D = (2.9 ± 0.3) × 10⁻⁸ cm²/s, and for the supercoiled DNA, D = (4.11 ± 0.21) × 10⁻⁸ cm²/s. The contribution to the correlation function from the internal dynamics of the DNA was seen to result in a strictly bimodal decay function. The rates of the faster mode Γ_int, reached plateau values at low angles. For the nicked DNA, Γ_int = 2500 ± 500 s⁻¹, and for the supercoiled DNA, Γ_int = 5000 ± 500 s⁻¹. These rates correspond to the slowest internal relaxation modes of the DNAs. The dependence of the relaxation rates on scattering vector was monitored with the aid of cumulants analysis and compared with theoretical predictions for the semiflexible ring molecule. The internal mode rates and the dependence of the cumulants moments reflected the difference between the nicked DNA and the supercoiled DNA dynamical behavior. The supercoiled DNA behavior seen here indicates that conformational dynamics might play a larger role in DNA behavior than is suggested by the notion of a branched interwound structure. © 1996 John Wiley & Sons, Inc.     

Thermophysiological responses of human volunteers during controlled whole-body radio frequency exposure at 450 MHz

Thermoregulatory responses of heat production and heat loss were measured in seven adult volunteers (four women and three men, aged 21–57 yr) during 45-min dorsal exposures of the whole body to 450 MHz continuous wave radio frequency (RF) fields. Two power densities (PD) (local peak PD = 18 and 24 mW/cm²; local peak specific absorption rate = 0.320 [W/kg]/[mW/cm²]) were tested in each of three ambient temperatures (T_a = 24, 28, and 31 °C) plus T_a controls (no RF). No changes in metabolic heat production occurred under any exposure conditions. Vigorous increases in sweating rate on back and chest, directly related to both T_a and PD, cooled the skin and ensured efficient regulation of the deep body (esophageal) temperature to within 0.1 °C of the normal level. Category judgments of thermal sensation, comfort, sweating, and thermal preference usually matched the measured changes in physiological responses. Some subtle effects related to gender were noted that confirm classic physiological data. Our results indicate that dorsal exposures of humans to a supra-resonant frequency of 450 MHz at local peak specific absorption rates up to 7.68 W/kg are mildly thermogenic and are counteracted efficiently by normal thermophysiologic heat loss mechanisms, principally sweating. Bioelectromagnetics 19:232–245, 1998. Published 1998 Wiley-Liss, Inc.     

Determination of corneal gel dynamics

From observations of the dynamics of light scattered by the cornea, intensity autocorrelation func-tions that revealed two independent diffusion coefficients, D (fast) = 2.4±0.2×10^–7 cm²/s and D (slow) = 9.4±1.3× 10^–9 cm²/s, were obtained. The diffusion coefficients were found to be statistically independent of the position and depth on the lateral surface of the cornea from which the scattered light was sampled. The slow diffusion coefficients obtained from light sampled from within cross-sections of the cornea were, however, measurably different. Diffusion coefficients obtained independently from observations of the kinetics of corneal swelling for comparison were found to be several orders of magnitude greater than those obtained from light scattering. The large disparity in the diffusion coefficients obtained from the two independent methods invoked the possibility that the lamellar layers within the cornea behave as individual gel sheets. Irrespective of this additional hypothesis, divergent behavior in the measured total scattered light intensities and diffusion coefficients upon varying external conditions, such as temperature or pressure (stretching), was observed. Namely, a slowing down of the dynamic modes accompanied by increased “static” scattered light intensities was observed. Although the slowing down of the dynamic modes is possibly indicative of the reduced affinity of protein binding to the gel matrix that “softens” the gel, the divergent behavior in the scattered light intensities and diffusion coefficients is, however, more characteristic of a phase transition. In addition, the divergent behavior in the scattered light intensities and diffusion coefficients was reversible up to a critical temperature (∼55 °C) or stretching (∼16%). Received: 18 March 1998 / Revised version: 4 February 1999 / Accepted: 4 February 1999     

Soil carbon inventories and δ13C along a moisture gradient in Botswana

We present a study of soil organic carbon (SOC) inventories and δ¹³C values for 625 soil cores collected from well‐drained, coarse‐textured soils in eight areas along a 1000 km moisture gradient from Southern Botswana, north into southern Zambia. The spatial distribution of trees and grass in the desert, savannah and woodland ecosystems along the transect control large systematic local variations in both SOC inventories and δ¹³C values. A stratified sampling approach was used to smooth this variability and obtain robust weighted‐mean estimates for both parameters. Weighted SOC inventories in the 0–5 cm interval of the soils range from 7 mg cm^?2 in the driest area (mean annual precipitation, MAP=225 mm) to 41±12 mg cm^?2 in the wettest area (MAP=910 mm). For the 0–30 cm interval, the inventories are 37.8 mg cm^?2 for the driest region and 157±33 mg cm^?2 for the wettest region. SOC inventories at intermediate sites increase as MAP increases to approximately 400–500 mm, but remain approximately constant thereafter. This plateau may be the result of feedbacks between MAP, fuel load and fire frequency. Weighted δ ¹³C values decrease linearly in both the 0–5 and 0–30 cm depth intervals as MAP increases. A value of –17.5±1.0‰ characterizes the driest areas, while a value of ?25±0.7‰ characterizes the wettest area. The decrease in δ ¹³C value with increasing MAP reflects an increasing dominance of C₃ vegetation as MAP increases. SOC in the deeper soil (5–30 cm depth) is, on average, 0.4±0.3‰ enriched in ¹³C relative to SOC in the 0–5 cm interval.     

Reduction of Visceral Adipose Tissue and Improvement of Metabolic Indices: Effect of Dexfenfluramine in NIDDM

Increased visceral adipose tissue is thought to contribute to impaired glucose tolerance. We studied 10 men with non-insulin dependent diabetes (NIDDM) before and after a 12-week intervention study using dexfenfluramine. Subjects had a mean body mass index (BMI) of 26.4 ± 1.7 kg\m² and had an abdominal distribution of body fatness (waist-to hip ratio >0.9). Anthropometric indices, biochemistry, macronutrient intake from 7-day food records as well as a euglycaemic glucose clamp and magnetic resonance imaging (MRI) were performed at week 0 and week 12. Abdominal adipose tissue area measured by MRI was reduced from 854 ± 270 cm² to 666 ± 231 cm² (p=0.003) due mainly to a selective 32% reduction in visceral fat area from 484 ± 230 cm² to 333 ± 72 cm² (p=0.002). Insulin sensitivity improved from 0.29 ± 0.13 [min^?1 (mU/L)] to 0.54 ± 0.21 [min^?1 (mU/L)] (p=0.01) and C-peptide levels reduced from 0.77 ± 0.24 μmol/L to 0.58 ± 0.15 μmol/L (p=0.002). The reductions in fasting glucose and glycated haemoglobin failed to achieve significance. Fasting total cholesterol and triglyceride levels significantly reduced (p=<0.001 and p=0.021 respectively). There was a reduction in total energy intake (p=0.005) due to a significant reduction in calories obtained from fat (p<0.001). Thus dexfenfluramine was shown to be a useful adjunct therapy for the reduction of visceral fat in abdominally-obese men with NIDDM with an associated improvement in insulin sensitivity.     

Effect of periphyton on growth performance of grey mullet, Mugil cephalus (Linn.), in inland saline groundwater ponds

The present study attempts to assess the potential of artificial substrates to enhance fish production in inland saline groundwater ponds through periphyton production. Grey mullet, Mugil cephalus, was cultured for 100 days in ponds with substrate (treatment ponds) and without substrate (control ponds). To enhance the surface area, bamboo poles were used as substrate. The periphyton population, pigment concentration and hydrobiological characteristics of pond water were monitored. The studies revealed little difference in most of the water quality parameters observed in the two treatments. However, turbidity (27.0 ± 0.1–35.0 ± 0.1 Nephalo Turbidity Unit (NTU)), chlorophyll ‘a’ (6.6 ± 0.6–7.6 ± 0.6 μg L^?1), plankton population (phytoplankton 8.4 × 10³–9.4 ×10³ numbers L^?1; zooplankton 4.0 × 10³–5.1 × 10³ numbers L^?1) and NH₄–N (2.0 ± 0.2–2.3 ± 0.1 mg L^?1) were high in the treatment with no additional substrate; however, in the treatment with substrate the total Kjeldahl nitrogen (9.8 ± 0.8–10.8 ± 0.7 mg L^?1) and o‐PO₄ (0.1 ± 0.01–0.1 mg L^?1) remained significantly (P < 0.05) higher. Highest periphyton biomass in terms of dry matter (DM) (0.8 ± 0.01–1.4 ±0.01 mg cm^?2), ash free DM (0.4 ± 0.0–0.6 ± 0.01 mg cm^?2), chlorophyll ‘a’ (3.1 ± 0.2–8.1 ± 0.8 μg cm^?2) and pheophytin ‘a’ (1.9 ± 0.4–3.9 ± 0.5 μg cm^?2) was observed at 50 cm depth in ponds provided with additional substrate. Fifteen plankton genera showing periphytic affinity colonized the bamboo substrates. Fish growth (mean fish weight 524.3 ± 8.7 g and SGR 2.5 ± 0.1) was significantly (P < 0.05) higher in ponds provided with additional substrate compared with control ponds (387.2 ± 6.0). Length–weight relationship (LWR) (W = cLⁿ) also showed that the exponential value (‘n’) of length was high in substrate‐supported ponds (n = 2.36) in comparison with controls (n = 1.09). These studies suggest that a periphyton‐supported aquaculture system can be used successfully for the culture of herbivorous brackishwater fish species like M. cephalus in inland saline groundwaters and thus could contribute to the development of sound and sustainable aquaculture technology.     

Dioptrics of the facet lenses in the dorsal rim area of the cricket Gryllus bimaculatus

1. The optics of the corneal facet lenses from the dorsal rim area (DRA) and from the dorso-lateral areas (DA) of the compound eye of the cricket Gryllus bimaculatus were studied.
2. The DRA of the cricket eye contains quite normally shaped facet lenses. The diameter of the facet lens in the DA is 2-fold larger compared to that in the DRA. The radius of curvature of the front surface is distinctly less in the DA facet lenses, as the surface of the facet lenses in the DRA are virtually flat.
3. The averaged axial refractive index of the facet lenses of Gryllus bimaculatus, measured by interference microscopy, was 1.496 ± 0.008 (n = 42) in the DRA and 1.469 ± 0.004 (n = 39) in the DA. The geometrical thickness of the lenses was calculated to be 77 ± 3 μm (n = 42) in the DRA and 56 ± 1 μm (n = 39) in the DA.
4. Analysis of the diffraction pattern obtained with a point light source revealed distinct focusing properties of both the DRA and the DA facet lenses; striking Airy-like diffraction patterns were obtained in both cases.
5. Focal distances measured directly at the backfocal plane were 40 ± 8 μm (n = 84) in the DRA of all the animals studied, and 60–90 μm (n = 62) in DA depending on the animal. Analysis of the diffraction of the point light source yielded very similar focal distances: 40 ± 5 μm (n = 10) in DRA and 81 ± 8 μm (n = 11) in DA. In the DRA, focal distance of the facet lenses was smaller than the cone length, 58 ± 3 μm (n = 9) while in the DA the focal distance matched the effective cone length, 71 ± 5 μm (n = 16).

     

Hydrodynamic properties of mushroom tyrosinase

The hydrodynamic properties of mushroom tyrosinase were determined at pH 6.5 using a Sephadex G-200 column. From the comparison of its gel-filtration behaviour with those of standard proteins, the following parameters were calculated: MW (122 500 ± 1%), Stokes' radius (42.75 × 10^?8 cm²/sec), diffusion coefficient (5.048 × 10^?7 cm²/sec) and frictional ratio (1.26). These values suggest a globular conformation of this enzyme.     

内生真菌Preussia sp.液体发酵生产抗肿瘤活性产物Spiropreussione A 的研究

螺光黑壳菌酮A(Spiropreussione A,SP-A)是编号为AS-5的光黑壳属内生真菌Preussia sp.的代谢产物。体外实验表明SP-A对人卵巢癌细胞A2780和人肝癌细胞BEL-7404的半数抑制浓度(IC50)分别为2.4和3.0μmol/L。以SP-A的含量为主要指标,结合AS-5的生物量,通过单因素实验和正交实验,优化确定了适合SP-A积累的AS-5液体发酵培养基和培养条件。研究结果表明:AS-5发酵生产SP-A的最优培养基为葡萄糖2%,麦麸3%,磷酸二氢钾0.3%,硫酸镁0.15%,pH7.0;该菌株最佳摇瓶发酵条件为250mL摇瓶装125mL培养基,接种6片直径9mm的PDA菌片,培养温度25℃,发酵周期16d。在此条件下发酵,SP-A的含量可以达到(25.02±1.02)mg/瓶,比优化前的含量[(17.08±3.24)mg/瓶]提高了46.5%。     

Microwave radiation (2450 MHz) alters the endotoxin-induced hypothermic response of rats

The parenteral administration of bacterial endotoxin to rats causes a hypothermia that is maximal after approximately 90 minutes. When endotoxin-injected rats were held in a controlled environment at 22°C and 50% relative humidity and exposed for 90 minutes to microwaves (2450 MHz, CW) at 1 mW/cm², significant increases were observed in body temperature compared with endotoxintreated, sham-irradiated rats. The magnitude of the response was related to power density (10 mW/cm² > 5 mW/cm² > 1 mW/cm²). Saline-injected rats exposed for 90 minutes at 5 mW/cm² (specific absorption rate approximately 1.0 mW/g) showed no significant increase in body temperature compared with saline-injected, sham-irradiated rats. The hypothermia induced by endotoxin in rats was also found to be affected by ambient temperature alone. Increases in ambient temperature above 22°C in the absence of microwaves caused a concomitant increase in body temperature. This study reveals that subtle microwave heating is detectable in endotoxin-treated rats that have an impaired thermoregulatory capability. These results indicate that the interpretation of microwave-induced biological effects observed in animals at comparable rates and levels of energy absorption should include a consideration of the thermogenic potential of microwaves.     

Inverted Tandem Polymer Solar Cells with Polyethylenimine‐Modified MoOX/Al2O3:ZnO Nanolaminate as the Charge Recombination Layers

A new charge recombination layer for inverted tandem polymer solar cells is reported. A bilayer of MoO_X/Al₂O₃:ZnO nanolaminate is shown to enable efficient charge recombination in inverted tandem cells. A polymer surface modification on the MoO_X/Al₂O₃:ZnO nanolaminate bilayer increases the work function contrast between the two outward surfaces of the charge recombination layer, further improving the performance of tandem solar cells. An analysis of the electrical, optical, and surface properties of the charge recombination layer is presented. Inverted tandem polymer solar cells, with two photoactive layers comprising poly (3‐hexylthiophene) (P3HT):indene‐C₆₀ bisadduct (IC₆₀BA) for the bottom cell and poly[(4,8‐bis‐(2‐ethylhexyloxy)‐benzo[1,2‐b:4,5‐b']dithiophene)‐2,6‐diyl‐alt‐(4‐(2‐ethylhexanoyl)‐thieno[3,4‐b]thiophene))‐2,6‐diyl] (PBDTTT‐C):[6,6]‐phenyl C₆₁ butyric acid methyl ester (PC₆₀BM) for the top cell, yield an open‐circuit voltage of 1481 mV ± 15 mV, a short‐circuit current density of 7.1 mA cm^?2 ± 0.1 mA cm^?2, and a fill factor of 0.62 ± 0.01, resulting in a power conversion efficiency of 6.5% ± 0.1% under simulated AM 1.5G, 100 mW cm^?2 illumination.     

Operant behavior and colonic temperature of Macaca mulatta exposed to radio frequency fields at and above resonant frequencies

Five food-deprived rhesus monkeys were exposed to 225-MHz continuous-wave, and 1.3-GHz, and 5.8-GHz pulsed radiation to determine the minimal power densities affecting performance. The monkeys were trained to press a lever (observing-response) thereby producing signals that indicated availability of food. In the presence of the aperiodically appearing food signals, a detection response on a different lever was reinforced by a food pellet. Continuous, stable responding during 60-min sessions developed and was followed by repeated exposures to radiofrequency radiation. The subjects, restrained in a Styrofoam chair, were exposed to free-field radiation while performing the task. Colonic temperature was simultaneously obtained. Observing-response performance was impaired at increasingly higher power densities as frequency increased from the near-resonance 225 MHz to the above-resonance 5.8 GHz. The threshold power density of disrupted response rate at 225 MHz was 8.1 mW/cm²; at 1.3 GHz it was 57 mW/cm², and at 5.8 GHz it was 140 mW/cm². These power densities were associated with reliable increases in colonic temperatures above sham-exposure levels. The mean increase was typically in the range of 1°C, and response-rate changes were not observed in the absence of concomitant temperature increases. In these experiments increase of colonic temperature was a much better predictor of behavioral disruption than was either the power density of the incident field or estimates of whole-body-averaged rates of energy absorption.