Structured surface reflector design for oblique incidence beam splitter at 610 GHz.

An iterative alternate projection-based algorithm is developed to design structured surface reflectors to operate as beam splitters at GHz and THz frequencies. To validate the method, a surface profile is determined to achieve a reflector at 610 GHz that generates four equal-intensity beams towards desired directions of ±12.6° with respect to the specular reflection axis. A prototype is fabricated and the beam splitter behavior is experimentally demonstrated. Measurements confirm a good agreement (within 1%) with computer simulations using Feko, validating the method. The beam splitter at 610 GHz has a measured efficiency of 78% under oblique incidence illumination that ensures a similar intensity between the four reflected beams (variation of about 1%).

Dose-response function for the soiling of silica-soda-lime glass due to dry deposition.

Several exposure campaigns of silica-soda-lime window glass have been performed in 30 European sites and 1 in Canada in order to understand, quantify and model the phenomenon of soiling. In this purpose samples were exposed sheltered from the rain. Parallel to exposure, several meteorological parameters and pollution concentrations have been monitored. This paper shows first results on the establishment of a dose-response function for glass soiling. Statistical analyses show that PM(10) is not the only parameter, but also SO(2) and NO(2) atmospheric concentrations seem to be responsible for the optical impairment of glass surfaces, expressed as haze.

Modeling of soiling based on silica-soda-lime glass exposure at six European sites.

Samples of silica-soda-lime float glass, a material selected as a pertinent soiling sensor, were exposed for up to 28 months at four urban sites (Athens, Krakow, London and Prague) and at a semi-urban one (Monte Libretti, near Rome), sheltered from rain. This exhaustive experience permitted to complete and to test the generalisation ability of the results previously obtained on the same material, exposed according to the same protocol, during 24 months, at a single site (Paris). The model previously fitted for the Paris experiment, the Hill equation, could be successfully generalised for four other sites of exposure (Athens, Krakow, Prague and Rome). The analytical form of this model was interpreted in terms of a physical description of the soiling phenomenon. Some of the model coefficients were different from one site to another, depending on the specific environment of exposure (air pollution levels, meteorological factors), while the other ones were rather equivalent. The analysis of the model coefficients, on the one hand, led to an estimation of the period after which soiling is close to its saturation level, and on the other hand, it will permit to correlate these coefficients to the environmental factors, in order to select the most appropriate ones for building dose-response functions for soiling, with broad geographical application.

Scaling law in carbon nanotube electromechanical devices.

We report a method for probing electromechanical properties of multiwalled carbon nanotubes (CNTs). This method is based on atomic force microscopy measurements on a doubly clamped suspended CNT electrostatically deflected by a gate electrode. We measure the maximum deflection as a function of the applied gate voltage. Data from different CNTs scale into an universal curve within the experimental accuracy, in agreement with a continuum model prediction. This method and the general validity of the scaling law constitute a very useful tool for designing actuators and in general conducting nanowire-based nanoelectromechanical systems.

Evidence of pre-industrial air pollution from the Heads of the Kings of Juda statues from Notre Dame Cathedral in Paris.

Pollution originating from wood combustion characterised the urban atmospheres of the past and led to the formation of thin grey crusts on the surface of the stone of monuments. The grey crusts discovered on the Heads of the Kings of Juda statues, which adorned the facade of Notre Dame in Paris from the 13th century until 1792, constitute a material record of the effects of this ancient air pollution. The height at which the statues stood suggests that the effect was not the result of a point phenomenon, but was caused by a generalised pollution of the Paris atmosphere at the time.

Experimental study of umbilical cord length as a marker of fetal alcohol syndrome.

Umbilical cord length has long been investigated as a potential marker of intrauterine events that may place the neonate at risk for future adverse developmental sequelae. Experimentally, significantly shortened cords have been reported in association with prenatal exposure to common drugs of abuse. This study in rats reports the time course of effects on umbilical cord length of a daily maternal ethanol gavage (3,200 mg/kg) from gestational day 6 through termination of pregnancy at either day 17, 18, 19, or 20. A total of 786 fetuses derived from 60 litters were examined. Control fetuses demonstrated a linear increase in umbilical cord length and body weight gain during late gestation, findings that support previous studies. The body weights of the ethanol-exposed fetuses were reduced significantly on all gestational days examined, indicating intrauterine growth retardation, a characteristic of fetal alcohol syndrome. Similarly, acute fetal akinesia as well as long-term sequelae stemming from impaired neurological development would result from the elevated blood ethanol levels achieved in this study. The umbilical cords of ethanol-exposed fetuses were significantly shorter on gestational days 19 and 20 in comparison to their controls, while cord lengths on days 17 and 18 were not shortened significantly. A stretch hypothesis has been proposed suggesting that the degree of fetal activity is the main determinant of umbilical cord length. In rats, there is a physiologic diminution of the volume of amniotic fluid (oligohydramnios) in late gestation (day 19 to term), which restricts fetal movements but does not appear to alter the linear relationships between gestational age and cord length in controls, thus arguing against the stretch hypothesis. However, cord lengths in the ethanol-exposed fetuses plateaued in late gestation, suggesting possible adherence to a stretch hypothesis. This dichotomy is discussed emphasizing fetal growth and activity as well as intrauterine space.

The incidence of renal anomalies at full term in fetal rats is synergistically increased by estradiol (but not testosterone) supplementation on day 18 of alcoholic gestation.

BACKGROUND/PURPOSE: Fetal alcohol syndrome is characterized by facial dysmorphology, mental and growth retardation, and somatic anomalies including hydronephrosis. The authors sought to determine the influence of exogenous testosterone or estradiol on the incidence of hydronephrosis in a rodent model of fetal alcohol syndrome (FAS). METHODS: Pregnant rats were fed a liquid diet containing 35% ethanol-derived calories from gestation day 6 through 15, with exogenous testosterone or estradiol supplementation on day 18. On day 20, fetal kidneys were examined for evidence of hydronephrosis, and fetal serum estradiol concentrations were determined by radioimmunoassay. RESULTS: Maternal estrogen supplementation resulted in very high fetal serum estradiol levels that were not additionally increased by alcoholism. Despite this fact, the expression of renal malformations was highest in the alcoholic, estradiol-supplemented offspring. Additionally, the rate of renal malformations was significantly higher in the estrogen-supplemented alcoholic group than in the strictly estradiol animals, yet the fetal serum estradiol concentrations did not differ between the two groups. CONCLUSIONS: This suggests that ethanol may act synergistically with estradiol to increase the rate of renal anomalies including hydronephrosis. Such damage may persist via a suppression of normal testosterone-stimulated renal growth and development. FAS includes significant renal anomalies characterized by hydronephrosis in both animal models and affected children. Although the long-term functional sequelae of hydronephrosis and reflux are well known, the progression of renal disease in FAS children remains to be documented.

Enhanced cocaine self-administration in adult rats prenatally exposed to cocaine.

Rats that had been prenatally exposed to either cocaine or saline were examined as adults using continuous reinforcement (FR1) cocaine self-administration. Initially these rats were water-deprived and trained to bar-press for water; no differences across prenatal treatments were observed during this training phase. After complete rehydration and implantation of an intravenous cannula into the external jugular vein, animals were introduced to cocaine self-administration with a nocturnal and subsequent 3 h exposure. During daily test sessions rats were allowed to self-administer cocaine for 1 h/day. Prenatal cocaine exposure led to a marked and stable enhancement of the rates of self-administration for up to 13 days, the longest time point examined. These results suggest that prenatal cocaine exposure can alter cocaine reinforcement in adult animals.

4-Methylpyrazole blocks acetaminophen hepatotoxicity in the rat.

STUDY OBJECTIVE: To determine whether 4-methylpyrazole inhibits the hepatotoxic effects of acetaminophen in a rat model. DESIGN AND TYPE OF PARTICIPANTS: A nonblinded experiment using male Sprague-Dawley rats. INTERVENTIONS: Animals were divided into four groups. Groups 1 through 3 received 2,000 mg/kg acetaminophen by gavage; group 4 acted as a control. At four or eight hours, group 2 received 400 mg/kg 4-methylpyrazole; group 3 received 50 mg/kg 4-methylpyrazole. Blood samples were taken for measurements of serum AST and ALT levels. Livers were removed for microscopic examination and grading of necrosis. RESULTS: Lower AST and ALT levels were obtained for both the 400-mg/kg (P < .01) and 50-mg/kg (P < .05) doses of 4-methylpyrazole administered four hours after acetaminophen. Although mean AST and ALT levels also were lower when 400 and 50 mg/kg 4-methylpyrazole were administered eight hours after acetaminophen, these results were not statistically significant. Median necrosis scores were 3 for rats receiving acetaminophen alone, 0.5 for those receiving acetaminophen and 400 mg/kg 4-methylpyrazole (P < .05), 1 for those receiving acetaminophen and 50 mg/kg 4-methylpyrazole (P < .05), and 0 for control rats (P < .05). CONCLUSION: When administered four hours after a toxic dose of acetaminophen, 4-methylpyrazole significantly inhibits hepatotoxicity in the rat, as reflected by lower levels of serum transaminases and lesser degrees of hepatic necrosis.

Prenatal ethanol exposure alters ethanol-induced dopamine release in nucleus accumbens and striatum in male and female rats.

Using in vivo microdialysis, ethanol-induced dopamine release in nucleus accumbens and striatum was examined in adult male and female Long-Evans rats exposed prenatally to ethanol and in controls. Following dialysis, ethanol intake was measured in an operant paradigm. Control rats showed increased dopamine release in nucleus accumbens and striatum in response to 0.5 g/kg ethanol, but not to 1.0 g/kg. Fetal ethanol-exposed rats showed no dopamine response at 0.5 g/kg. At 1.0 g/kg, fetal ethanol-exposed males showed increased dopamine release in both structures. Prenatally exposed females showed no change in accumbens, and decreased release in striatum. Fetal ethanol exposure did not significantly influence ethanol intake. The findings suggest that prenatal ethanol exposure influences subsequent neurochemical responses to ethanol; however, how these neurochemical measures are related to ethanol intake could not be determined in the present study. Data are discussed in terms of sex-specific shifts in the dose-response function for ethanol-induced dopamine release resulting from prenatal ethanol exposure.

Preferential alcoholic embryopathy: effects of liquid diets.

Our initial report of a preferential expression of experimental alcoholic embryopathy affecting the male offspring contiguous in utero to male siblings of Long-Evans rats was based on gavage administration of alcohol to pregnant rats without regard to isocaloric, pair-fed exposure paradigms. In this study, pregnant Long-Evans rats were given 35% ethanol-derived calories (EDC) in one of two different liquid diets: 1) a liquid alcohol diet based on Sustacal, a flavored liquid food formulated for human nutritional standards; and 2) a high-protein liquid rodent diet devised by Lieber and DeCarli (L&D). The diets were administered from day 6 to 15 of gestation. Pregnant rats were pair-fed liquid diets containing 0% EDC, but isocalorically balanced to 35% EDC with either sucrose (Sustacal) or maltose-dextrin (L&D). A fifth group of pregnant rats was given access ad libitum to standard certified laboratory rodent diet and served as free-fed controls. On day 20 of gestation, all pregnant rats were euthanized and the products of conception examined by standard teratologic techniques. Pregnant animals fed Sustacal-based diets consistently consumed fewer calories per kilogram body weight per day from day 6 to 15 of gestation (i.e., they were significantly calorie-deprived during pregnancy) as compared with the standard laboratory-diet-fed controls or those consuming L&D diets. Body weights of rats consuming Sustacal diets (both 0 and 35% EDC) were significantly lower throughout gestation when compared with all other groups. Higher (> 150 mg/dl) blood alcohol levels were attained by rats consuming 35% EDC in Sustacal diet as compared with L&D (100 mg/dl) diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of intrauterine position on the hepatic microsomal polysubstrate monooxygenase and cytosolic glutathione S-transferase activity, plasma sex steroids and relative organ weights in adult male and female Long-Evans rats.

The intrauterine position of rat fetuses between siblings of the same or opposite sex has been reported to alter sexually dimorphic behavioral and reproductive traits in the adult. The intrauterine fetal position of adult rats is identified by a three letter code as mMm (a male, M, located between two male siblings, m-m) and fFf (a female, F, positioned between two females, f-f). This study sought to determine whether intrauterine location affected the hepatic polysubstrate monooxygenase and glutathione S-transferase activity, plasma sex steroid levels and organ weights in adult Long-Evans rats. The hepatic microsomal cytochrome P-450 content was higher in females located in utero between two male littermates (mFm) than in females positioned between two females (fFf). NADPH cytochrome c reductase activity was higher in mMm males (positioned in utero between two males) than in fMf males (males contiguous to two female littermates) and female rats. Hepatic microsomal testosterone 2 alpha- and 6 beta-hydroxylase activity was undetectable in fFf female but both activities were measurable in mFm female rats. Testosterone 7 alpha-hydroxylase and 5 alpha-reductase activity was higher in females than in males, and higher in fFf than in mFm females. Glutathione S-transferase activity was not altered by fetal contiguity in male and female rats. Adult mMm males had a higher plasma testosterone level and relative gonadal weight, and lower plasma estradiol concentration than fMf males. The plasma progesterone concentration of fFf female was lower than that of mFm female rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperactivity and altered amphetamine sensitivity in premature juvenile rats.

'Premature' rats that were delivered by cesarean section on day 21 of gestation and 'normal' rats that were delivered spontaneously on day 22 of gestation were tested for basal locomotor activity and locomotor stimulation in response to D-amphetamine at 19-21 days of age. Compared to normal rats, premature rats had increased basal levels of locomotor activity and showed enhanced sensitivity to the locomotor stimulant effects of D-amphetamine. Cesarean-delivered premature rats may be a useful animal model for investigating mechanisms of neurobehavioral deficits associated with premature birth in humans.

Alcohol preference and hepatic alcohol dehydrogenase activity in adult Long-Evans rats is affected by intrauterine sibling contiguity.

Alcohol preference and hepatic alcohol dehydrogenase activity in adult rats are known to be sexually dimorphic. Intrauterine sibling contiguity (the intrauterine position of a fetus relative to adjacent siblings of the same or opposite sex) alters selected reproductive, behavioral and enzymatic sexual dimorphisms via intersibling sex hormone transfer. We postulated that sibling contiguity would affect alcohol preference and hepatic alcohol metabolism in adult rats. The results of our study demonstrate that adult mMm male Long-Evans rats (genetic male rat developing in utero between two male siblings) had significantly lower ethanol preference, attained higher blood alcohol levels after standard ethanol "challenge" doses and had significantly lower hepatic alcohol dehydrogenase activity than either male siblings developing in utero between two females (fMf) or genetic females developing between two males or between two females (mFm or fFf). Hepatic cytosolic aldehyde dehydrogenase activity was higher in adult female than male rats regardless of nearest neighbor siblings. It is suggested that the differences in ethanol preference and hepatic alcohol dehydrogenase activity between the adult mMm and fMf male rats is due to differences in prenatal hormonal environment which can modulate sexual dimorphisms in alcohol intake and metabolism in the adult.

Lateral decompression of a pathological disc in the treatment of lumbar pain and sciatica.

The posterolateral approach external to the vertebral canal allows decompression and the escape of disintegrating bits of abnormal nucleus pulposus. This simple, rapid, and least traumatic procedure is sufficient to relieve and to cure a significant number of patients (approximately 40%) suffering from intervertebral disc-related lumbar pain or sciatica. Among 225 patients with 338 discs operated on by the lateral decompression technique in the interval from 1978 to 1984, the overall results are encouraging.