Influence of home-cage lighting conditions on shock-induced fighting

A series of experiments was conducted to assess the influence of home-cage lighting conditions on shock-induced aggression in rats. The first two experiments tested rats six times within 24 hr and demonstrated that subjects maintained on a light/dark (LD) cycle fought more than rats maintained on a 24-hr light schedule (LL). In addition, a periodic trend could be identified in the data of the LD groups but not in the data of the LL groups. The second two experiments assessed the effects of castration on this lighting effect. Castration of adults did not influence the lighting effects, but castration of weanling rats eliminated the group difference between LL and LD groups. However, the LD rats castrated at weaning did show the periodic trend characteristic of all of the LD groups tested within 24 hr. Two additional experiments assessed the effects of time of testing in between-subjects designs. Time of testing was a significant variable in the LD groups but unimportant in the LL groups. A final experiment demonstrated that the difference between the LD and LL groups does not emerge in a daily testing procedure.     

Technological Evaluation of Three Enteric Coating Polymers II. With a Soluble Drug

Three enteric coating polymers, cellulose acetate phthalate (CAP), hydroxy propylmethylcellulose phthalate (HP55) and cellulose acetate trimellitate (CAT) were evaluated on two different chemical substrates (soluble and insoluble). Gastric juice resistance was tested by dissolution using USP apparatus (paddle) in Britton buffer at different pH, under sink conditions over 5 hours. It can be said that the resistance of tablets depends on the coating formulation considered and the drug solubility. From our tests it results that CAP is more resistant than CAT for two drugs in intestinal medium and the resistance of HP55 depends on the solubility of the drugs. More, only CAT allows the release in the proximal small intestine for drugs whatever solubiliy.     

Inhibitory attentional mechanisms and aging

Two experiments sought to elicit distractor suppression in older adults. Experiment 1 used a procedure that increased suppression in younger adults, thus creating a more sensitive measure of suppression in older adults. To compensate for older adults' slowed processing, Experiment 2 used a longer stimulus exposure duration. Neither experiment produced suppression in older adults; both experiments, however, included trial types that elicited parallel facilitatory effects for both age groups. Older adults thus seemed to process distractors but failed to engage inhibitory mechanisms in their rejection of distracting stimuli. Finally, both experiments tested the relationships among suppression, interference, and everyday cognitive failure. Neither experiment suggested relationships between reaction time effects and self-reported cognitive lapses. Results are discussed within L. Hasher and R. T. Zacks's (1988) attentional framework.     

Active immunization alters the plasma nicotine concentration in rats

The ability of active immunization to alter nicotine distribution was studied in rats. Animals were immunized with 6-(carboxymethylureido)-(+/-)-nicotine (CMUNic) linked to keyhole limpet hemocyanin (KLH). Antibody titers determined by ELISA, using CMUNic coupled to albumin as the coating antigen, were greater than 1:10,000. Antibody binding was inhibited by neither of the nicotine metabolites cotinine and nicotine-N-oxide but was inhibited to a greater extent by CMUNic than by nicotine; this suggests the presence of antibodies to the linker structure as well as antibodies to nicotine. Antibody affinity for nicotine measured by soluble radioimmunoassay was 2.4 +/- 1.6 x 10(7) M-1, and binding capacity was 1.3 +/- 0.7 x 10(-6) M, which corresponds to 0.1 +/- 0.05 mg/ml of nicotine-specific IgG per milliliter of serum. One week after their second boost, groups of eight anesthetized rats immunized with either CMUNic-KLH or KLH alone received nicotine 0.03 mg/kg (equivalent to two cigarettes in a human) via the jugular vein over 10 sec. This dosing regimen was shown to mimic the arterio-venous nicotine concentration gradient typical of nicotine delivered by cigarette smoking in humans. Plasma nicotine concentrations at 10 to 40 min were 4 to 6-fold higher in the CMUNic-KLH rats than in controls (P < .001). Nicotine binding in plasma determined by equilibrium dialysis was markedly increased in the CMUNic-KLH group (83.4 +/- 6.8% vs. 16.4 +/- 14.2%), but brain nicotine concentrations at 40 min did not differ (37.9 +/- 4.5 vs. 44.0 +/- 8. 4 ng/g, CMUNic-KLH vs. KLH, P = .1). The amount of nicotine bound to antibody in plasma, estimated from the in vivo data, was 9% of the administered dose. These data demonstrate that active immunization can bind a significant fraction of a clinically relevant nicotine dose in plasma. Observing this effect with antibodies of modest affinity and titer is encouraging, but better immunogens may be needed to alter nicotine distribution to brain and modify nicotine's behavioral effects.     

A 1.5-GHz programmable divide-by-N GaAs counter

A GaAs divide-by-N programmable counter has been fabricated for use in microwave frequency synthesizers and other applications. The counter uses a 1-μm depletion-mode MESFET process. The counter is typically capable of dividing an input frequency of DC to 1.5 GHz by any divisor from 3 to 64 over a temperature range of -60 to 100°C. Input and output translators are incorporated to render the device fully compatible with emitter-coupled logic (ECL) logic levels. Power dissipation for the chip is 1.4 W. A custom gigahertz-rate automated digital IC tester has been used to characterize the counter. Reliability data to date indicate a minimum mean time to failure (MTTF) of 1.8×10⁶ h at 100°C     

Intravascular ultrasound. Three-dimensional applications and forward viewing

Variation in HIV-1 genomic RNA was studied in seroconversion samples from mother-child pairs from a Rwandan cohort. The mothers (n = 8) were heterosexually infected and their children (n = 6) were vertically infected by breast milk. Five of the children seroconverted within the same 3-month period as did their mothers. Highly homogeneous subtype A V3 and p17gag sequence populations were observed in three mother-child pairs, one of the two nontransmitting mothers, and one child (mean nucleotide distances 0 to 0.9%). Heterogeneous populations of subtype A V3 and p17gag sequences were found in one mother and a mother-child pair (1.4 to 2.8% for V3, 1.0 to 1.9% for p17). The second nontransmitting mother was infected with a heterogeneous AV1-V3/Cp17-p24 recombinant virus population (3. 8% for V3, 2.4% for p17). Finally, in one woman subtype C V3 sequences were observed, in addition to highly homogeneous subtype A V3 and p17gag sequence populations, also found in the child. Coexistence of subtype AV1-V3 and CV1-V3 env sequences in the mother was confirmed in a follow-up sample. The gag gene of both the maternal and the child's virus population represented an A/C recombinant sequence (Ap17/Cp24). An infection with subtype CV1-V3/p17-p24 was found upon testing of three additional participants of the mother-child cohort, indicating that subtype C is present in Rwanda. In conclusion, heterogeneity, coinfection, and intersubtype recombinants are not uncommon in primary HIV-1 infections in Rwanda.     

A terahertz optical asymmetric demultiplexer (TOAD)

A device capable of demultiplexing Tb/s pulse trains that requires less than 1 pJ of switching energy and can be integrated on a chip is presented. The device consists of an optical nonlinear element asymmetrically placed in a short fiber loop. Its switching time is determined by the off-center position of the nonlinear element within the loop, and therefore it can use the strong, slow optical nonlinearities found in semiconductors, which all other fast demultiplexers seek to avoid. The switch's operation at 50 Gb/s is demonstrated, using 600-fJ control pulses     

Hot workability of nickel-containing alloys after reheating using sulfur-containing fuel

The effects of fuel sulfur on the hot workability of several nickel-containing alloys have been explored in static exposures and in hot rolling trials following reheating in S-bearing. combustion atmospheres. Using thermochemical calculations, it is shown that the locus of oxidation and sulfidation potentials of such gases over practical air-fuel ratios can be made to coincide for a variety of hydrocarbon fuels, and propane doped with H₂S has been used as a fuel to simulate environments resulting from firing distillate and residual oils. Nickel-base alloys containing chromium are not affected by the presence of sulfur species, and workability is independent of reheating conditions at fuel sulfur levels of up to 2 wt pct. Stainless steels may form solid subscale sulfides under air deficient heating, but there is no effect under lean firing conditions; billet workability is not influenced by sulfur. Nickel and nickel-copper alloys form liquid sulfides during air deficient heating, and very poor workability results. Sulfur is also picked up from the gas, and other properties may be affected. The thermochemical predictions for the occurrence of these liquid sulfides agree well with observations. An attempt has been made to identify safe reheating conditions (temperature and air-fuel ratio) for sensitive alloys on the basis of equilibrium combustion gas computations.     

Investigating the potential of overheating in UK dwellings as a consequence of extant climate change

Dynamic simulation is used with defined domestic building variants to investigate internal temperatures of UK dwellings. Factors such as a warming climate and varying internal heat gains are estimated to examine whether UK domestic buildings are likely to be prone to overheating in the future, and therefore require mechanical air conditioning. The study suggests that the ability, or inability, of the occupant to adapt to bedroom temperature is paramount in the understanding of the conditions for overheating. While this is difficult to quantify (and a range of comfort temperatures are proposed), the effect of changing the building construction and geographical location can result in significantly different thermal conditions. As might be expected, the problem appears most noticeable for buildings in the south of the UK and with lightweight constructions. Even with a window-opening schedule applied to such a scenario, the average internal temperature is simulated as being over 28 °C for almost 12% of the year. A different metric, defined as “cooling nights”, suggests that there might be a cooling problem in bedroom areas for approximately a third of the year. In the North of the UK, and also for solid wall dwellings, this problem diminishes significantly.