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Previous work has demonstrated that melatonin inhibits growth of cultured human uveal melanoma cells. The goal of this study was to determine the expression of mRNA encoding the melatonin receptor subtypes and the effect of specific melatonin receptor agonists on cell growth of uveal melanoma cells and melanocytes. RNA expression of the human melatonin Mel1a and Mel1b receptor subtypes was determined by reverse transcription-polymerase chain reaction (RT-PCR) amplification of RNA isolated from two melanoma cell lines and from one cell line of normal melanocytes. PCR-amplified cDNA encoding the Mel1b melatonin receptor subtype, but not the Mel1a subtype, was detected in reverse-transcribed RNA obtained from both normal uveal melanocytes and melanoma cell lines. Uveal melanoma cells and melanocytes were cultured for 24 hr, then melatonin or one of its membrane receptor agonists, 6-chloromelatonin (Mel1a-1b) or S-20098 (Mel1b) or its putative nuclear agonist, CGP-52608 (Mel2), was added to the medium. After 5 days, the cells were detached, counted, and compared to untreated controls. Melatonin and its membrane receptor agonists (Mel1a-1b and Mel1b), but not its putative nuclear receptor agonist (Mel2), inhibited the growth of uveal melanoma cells, but not normal melanocytes, at very low concentrations. In uveal melanoma cells, the expression of RNA encoding the Mel1b receptor suggests that the growth inhibiting effect of melatonin on uveal melanoma cells is related to activation of the melatonin Mel1b membrane receptor. Furthermore, the expression of RNA encoding melatonin receptors in normal uveal melanocytes suggests that melatonin may play a role in the function of these cells.

High doses of light can cause damage to the retina, e.g. during intraocular surgery. Previously, thiols have been demonstrated to protect against retinal damage in various damage models. Such protection is very promising for clinical practice. Retinal light damage can be caused by a relatively short exposure to high irradiance levels. These conditions occur during intraocular surgery. In the current study we therefore investigated whether the thiol N-acetylcysteine protects against retinal light damage under high irradiance conditions in the rat retina. Two stereoisomers of this thiol were tested for protection against two spectrally defined types of retinal light damage. Shortly after administration N-acetyl-L-cysteine in doses of 270-1000 mg/kg intraperitoneally protected against 380 nm (UVA) light but not against 470 nm (blue) light. Two hours after injection the protection had diminished. We observed no protection by the stereoisomer N-acetyl-D-cysteine. From this study we conclude that N-acetyl-L-cysteine protects stereospecifically against retinal damage in the UV but not in the visible part of the spectrum. This limits the possible applications.

Our purpose was to evaluate the effects of various concentrations of hydrosalpingeal fluid (HSF) on the preimplantation development and implantation of murine embryos.One-cell mouse embryos were cultured in KSOM culture medium with 0.1, 1.0, 10, or 50% HSF, without and with lactate supplementation. Late-stage embryos were transferred into the uteri of pseudopregnant CD-1 females to determine implantation rates. The embryo transfer technique used was developed by our group and its effectiveness was evaluated during this experiment.Blastocyst development in the 0.1, 1.0, 10, and 50% group was 45, 55.0, 12.5, and 17.5%, respectively, with lactate supplementation, and 35.0, 52.5, 12.5, and 5.0%, respectively, without lactate supplementation, while in the KSOM (control) group it was 63.8%. Blastocyst development was reduced compared to controls in the 10% HSF and 50% HSF groups. Implantation rates for the 0.1 and 1.0% groups with lactate supplementation were 43.0 and 25.0%, respectively, and those with lactate supplementation were 50.6 and 61.8%, respectively, while in the KSOM group the implantation rate was 65.5%. None of the implantation rates were significantly different.Hydrosalpingeal fluid has a concentration-dependent inhibitory effect on in vitro murine embryo development, but it has minimal effects on implantation rates.

Most drugs used in the treatment of malaria produce phototoxic side effects in both the skin and the eye. Cutaneous and ocular effects that may be caused by light include changes in skin pigmentation, corneal opacity, cataract formation and other visual disturbances including irreversible retinal damage (retinopathy) leading to blindness. The mechanism for these reactions in humans is unknown. We irradiated a number of antimalarial drugs (amodiaquine, chloroquine, hydroxychloroquine, mefloquine, primaquine and quinacrine) with light (lambda300 nm) and conducted electron paramagnetic resonance (EPR) and laser flash photolysis studies to determine the possible active intermediates produced. Each antimalarial drug produced at least one EPR adduct with the spin-trap 5,5-dimethyl-1-pyrroline N-oxide in benzene: superoxide/hydroperoxyl adducts (chloroquine, mefloquine, quinacrine, amodiaquine and quinine), carbon-centered radical adducts (all but primaquine), or a nitrogen-centered radical adduct only (primaquine). In ethanol all drugs except primaquine produced some superoxide/hydroperoxyl adduct, with quinine, quinacrine, and hydroxychloroquine also producing the ethoxyl adduct. As detected with flash photolysis and steady-state techniques, mefloquine, quinine, amodiquine and a photoproduct of quinacrine produced singlet oxygen ([symbol: see text]delta = 0.38; [symbol: see text]delta = 0.36; [symbol: see text]delta = 0.011; [symbol: see text]delta = 0.013 in D2O, pD7), but only primaquine quenched singlet oxygen efficiently (2.6 x 10(8) M-1 s-1 in D2O, pD7). Because malaria is a disease most prevalent in regions of high light intensity, protective measures (clothing, sunblock, sunglasses or eye wraps) should be recommended when administering antimalarial drugs.

A sample of 57 boys with fragile X syndrome (fraX) between the ages of 24 and 133 months was rated using the Childhood Autism Rating Scale (CARS) to assess the extent to which autism and autistic features were evident in a young population. Fourteen subjects (approximately 25% of the sample) scored above the cutoff for autism, suggesting a relatively high incidence of autistic behavior. All but 2 of these 14 were in the mildly or moderately autistic range, however, and only a few items received severe ratings, suggesting that severe autism is relatively rare in fraX, at least during the early years. The CARS resulted in a continuum of autistic ratings in the fraX population, but no particular items on the CARS contributed disproportionately to autism ratings. A visual comparison of ratings on an autistic, non-fraX sample revealed similar profiles of ratings, suggesting that differentiating fraX and autism on the basis of CARS ratings is not likely. Within the fraX group, chronological age and socioeconomic status did not correlate with CARS ratings, but severity of delay was strongly related, such that more severely delayed children scored higher (more autistic) on the CARS.

Measuring the concentration of oxygen in the aqueous humor without penetrating the eye would provide a new dimension in understanding aqueous humor and corneal dynamics. In this study a preinvasive method was developed for determining the cameral oxygen concentration in anesthetized rabbits by measuring the excited-state lifetime of a phosphorescent dye.A scanning ocular fluorometer was designed to excite phosphorescence with a brief flash of light and to measure the decay of luminescence for as long as 1000 microsec after excitation. The measurement window was scanned through the depth of the anterior chamber or fixed at the mid-anterior chamber. A depot of the phosphorescent dye Pd-uroporphyrin was injected into the vitreous of eight pigmented rabbits, and within a few days the dye was measurable in the anterior chamber. The excited-state lifetime of this dye is inversely correlated to oxygen concentration and was calibrated by measuring the lifetime of dye in cuvettes equilibrated with oxygen-nitrogen mixtures. Oxygen tensions were determined from lifetimes measured in the open eye, under a polymethylmethacrylate (PMMA) contact lens, under two oxygen-permeable contact lenses, and immediately after lid closure.Oxygen tension in the mid-anterior chamber before placing a PMMA contact lens was 23 +/- 3 mm Hg (mean +/- SD; n = 6). After 20 minutes of PMMA lens wear, oxygen tension decreased to 4 +/- 2 mm Hg. When the focal diamond was scanned through the anterior chamber, oxygen tension was 24 +/- 5 mm Hg near the corneal endothelium and decreased to 17 +/- 8 mm Hg near the crystalline lens. Under the PMMA contact lens this gradient reversed: Oxygen tensions near the endothelium and lens were 3 +/- 2 mm Hg and 6 +/- 2 mm Hg, respectively. Lid closure for 10 minutes or longer decreased the mid-anterior chamber oxygen tension from 21 +/- 2 mm Hg (n = 19 measurements from seven animals) to 10 +/- 3 mm Hg (n = 15 measurements from five animals).Measuring excited-state lifetime of phosphorescent dyes in the anterior chamber provides a useful method for determining oxygen concentration in vivo, without penetrating the eye. Cameral oxygen tension under PMMA contact lenses are significantly lower than in the uncovered eye. The profile of oxygen tension through the anterior chamber suggests that oxygen is supplied transcorneally to the aqueous humor.

Recent studies have found that temporal variability and reactivity in self-esteem (SE) are associated with risk for depressive symptoms subsequent to life stress. It is unclear, however, whether it is variability uniquely in SE that is critical, or whether variability in other domains, such as specific self-evaluation (SSE) and affect, would show similar effects. Further, the specificity of these effects to depression is unknown. In the present study, initially nondepressed women completed 7 daily ratings of SE, SSE, and affect. Over a 6-week prospective interval, the interactions of stressful life events and variability in both SE and SSE predicted changes in depression, particularly in individuals with more severe worst lifetime episodes of depressive symptoms. These effects were independent of average level of SE and SSE, as well as neuroticism and self-concept uncertainty. In contrast, variability in affect failed to predict changes in depression in interaction with life stress. Finally, none of the predictor variables interacted with stressful life events in predicting changes in anxiety.

Asked what relativistic quantum field theory contributes to our understanding of physical phenomena, we would point to the anomalous magnetic moment of the electron or the success of the standard model. These are the nuggets of gold from the el dorado of gauge theories. But success and disaster lie close at hand: imagine a gauge theory given in terms of its observable quantites and ask what features might betray its origin as a gauge theory, the suggestions are few and unconvincing. The guiding geometrical ideas, such as Lagrangian, gauge group, gauge—fixing, vector bundles, connexions, curvature, have stolen from the stage. Perhaps gauge theories should have a characteristic structure in non—commutative geometry. Renormalized perturbation theory, designed to deal with divergences, is unlikely to effect a passage from commutative to non—commutative geometry.

Life stress was studied in relation to postrecovery attrition, symptom course, and recurrence of depression over 3 years. Participants were 67 individuals with recurrent depression who had responded to treatment. Life stress was assessed for the prior 12 weeks at acute treatment entry (T1), initial recovery (T2), and after 17 weeks of sustained recovery (T3). Severe life events at T1 predicted greater attrition, a more favorable postrecovery symptom course, and a lower likelihood of recurrence over 3 years. Life stress at T2 was not predictive of outcomes. Finally, undesirable life events at T3 tended to predict a worse symptom course and a higher likelihood of recurrence, particularly for individuals on medication. The findings are discussed in terms of (a) different processes influenced by life stress over time and (b) limitations of existing longitudinal research for studying the effects of life stress over prolonged intervals.

Three studies investigated the relation between adult attachment security and symptoms of depression. Study l examined the overall magnitude of the association between adult attachment and depression, and Studies 2 and 3 tested whether this relation was mediated by dysfunctional attitudes and low self-esteem. Results from the three studies were consistent with a mediation model. This model suggests that insecure adult attachment styles are associated with dysfunctional attitudes, which in turn predispose to lower levels of self-esteem. Such depletions in self-esteem are directly associated with increases in depressive symptoms over time. Insecure attachment appears to lead to depressive symptoms in adulthood through its impact on self-worth contingencies and self-esteem.

To the Editor .— The results of the meta-analysis by Roberts et al1 suggested no to very small negative associations of otitis media with effusion (OME) and associated hearing loss to children’s later speech and language development. This conclusion is in accordance with the available evidence; ie, most studies performed thus far indeed have not shown a clear association. The methods used in the meta-analysis, however, are incorrect, and the readers of Pediatrics should be aware of this. First, the authors pooled the data of 3 randomized, controlled trials and 4 observational studies. All randomized, controlled trials included in the meta-analysis studied the effect of treatment with ventilation tubes on speech and language in children with persistent OM, whereas the observational studies investigated the effect of OM on the speech and language development in open populations. In the meta-analysis, Roberts et al classified the group with the least OM as “OM−” and the one with the most OM as “OM+”; ie, the children with persistent OME treated with …

The purpose of this single-subject pilot study was to examine the efficacy of FM amplification for enhancing the discourse skills of a 4-year-old girl with a history of speech-language impairments, otitis media with effusion (OME), and motoric delays. Over a period of several weeks, language treatment sessions were conducted with and without FM amplification, in a classroom setting. Sessions were videotaped and analyzed for the appropriateness and effectiveness of the subject's conversational turns during sessions with amplification and with no amplification. Although the number of sessions was small, more appropriate and effective conversational turns occurred during sessions with amplification.

The drugs commonly used in the treatment of malaria are photochemically unstable. Several of these compounds cause dermal and ocular toxic reactions that may be light induced. The in vitro photopolymerization of calf lens proteins in the presence of antimalarial drugs was studied as part of a screening of the photochemical properties and phototoxic capabilities of these compounds. The pseudo-first-order rate constant for the reaction was calculated, and related to the amount of light absorbed by the compounds in order to determine the relative photosensitizing effect of each drug. The reaction mechanisms were evaluated by adding a variety of quenchers to the reaction medium during irradiation. Based on the results obtained in this study and previous knowledge about the pharmacokinetic behavior of these compounds, several of the drugs investigated have to be considered as potential photosensitizers in the human lens, the retina and the skin.

In an open trial in 9 patients, we found that the ingestion of 500 mg of cysteine twice a day could prevent or lessen the photosensitivity associated with erythropoietic protoporphyria (EPP). We report here the results of a double-blind cross-over design trial in 16 patients. Patients with EPP were randomized into two groups, one that received 500 mg twice daily of cysteine during the first period and then placebo during the second period, and the second that received placebo first and then cysteine. Each drug ingestion period lasted 8 weeks, and there was a 1 week wash-out period between them. Patients were seen before the first period, at the end of the first period and at the end of the second period for phototesting, an objective method of assessing treatment efficacy, and for blood tests to monitor cysteine safety. The subjects also were asked to keep light-exposure diaries, a subjective method of assessing efficacy. We found that cysteine significantly prolonged the time it took to develop erythema by phototest, objectively demonstrating efficacy. In addition, analysis of patients' diaries showed that cysteine ingestion significantly increased the length of sun exposure it took to develop symptoms of photosensitivity. We conclude that cysteine ingestion may be an effective therapy in the prevention of photosensitivity associated with EPP.

Communicative interactions of preschool children with and without disabilities in classrooms of same or mixed ages were compared. Sixteen children with developmental disabilities (most with mild or moderate mental retardation) and 32 children without disabilities between 1.5 and 4.5 years of age were randomly assigned at the beginning of the school year to either a same- or mixed-age grouping of 6 children. They were observed 6 months later interacting with classmates in a standard free-play environment. Results showed that children in mixed-age classes took more turns in conversations with partners with disabilities than did children in same-age classrooms. They also received more turns from their partners with disabilities, which were more often responses than initiations in the mixed-age as compared to same-age classes. In contrast, during communicative interactions with partners without disabilities, children in both types of classes did not significantly differ in number or types of turns. Children of a similar developmental level also had similar communicative interaction styles.

The adsorption behavior of model associative polymers in aqueous titanium dioxide (TiO2) and polystyrene latex (PS) particle dispersions has been studied using liquid-state Nuclear Magnetic Resonance (NMR) and a modified serum replacement technique (SRT). The structure of the associative polymer is a linear, water soluble, A-B-A block copolymer with a polyethylene oxide backbone and hydroxyl (H) or hexadecyl (C16H33) endgroups.Absolute intensity NMR measurements allow the determination of the adsorbed polymer configuration at the solid-solution interface and adsorption isotherms for comparison to the SRT results. Both the SRT and NMR results demonstrate that the adsorption/desorption of the C16 and H polymers is strongly affected by the substrate. For the polymer/PS particle systems, there is good agreement in complete surface saturation values for the SRT and NMR methods. In the polymer/TiO2 systems, the H polymer plateau as determined by NMR differs slightly from that determined by SRT. For the C16/TiO2 system the interpretation is less straightforward. Either the NMR saturation value is at least double that of the SRT value or the C16 and H polymers have very similar isotherms by NMR. This would suggest that on TiO2 the effect of the hydrophobe is minimal. For all the polymers the polymer/particle interaction on PS is strong and desorption is difficult while on TiO2 it is weak and completely reversible. A pancake-to-brush conformation change on the PS surface is evident for the C16 polymers and probably for the H polymer as well. The H polymer seems to form a multi-layered structure on PS from the NMR and laser light scattering results. The contribution of the hydrophobe and the effect of increasing the backbone molecular weight are clearly illustrated.

Across diverse theoretical orientations, vulnerable self-esteem (SE) is thought to act as a diathesis for depression after life stress. In the present study, the roles of trait-level SE, low SE primed by depressed mood, and labile SE in prospectively predicting changes in depressive symptoms in a nonclinical sample (n = 192) were examined. Results indicated that labile SE predicted increases in symptoms. Furthermore, a 3-way interaction (Labile SE x Academic Stress x Initial Depression) suggested that in Ss who were initially asymptomatic, lability made Ss differentially vulnerable to increases in depressive symptoms after stress. In contrast to labile SE, trait-level SE and priming of low SE were relatively weak predictors of changes in depressive symptoms and did not interact with stress.

Light Therapy is a new treatment for patients with Seasonal Affective Disorder (SAD), a depressive state occurring during the winter as a result of decreased sunlight. The treatment involves placing the patient in front of a light box (2-10,000 lux) for approximately 30 min to 1 hour per day during the winter months. Although there have been no reports of damage to the eye from this treatment with light alone there is increased risk in light damage to the lens and retina if these depressed patients are being treated with antidepressant/neuroleptic drugs concurrently with their light therapy. As we have been previously reported certain drugs, having absorptions longer than 295 nm can act as photosensitizers resulting in enhanced light damage to the eye. Using a screening method developed by Roberts, we examined the potential phototoxicity of a variety of antidepressant and neuroleptic drugs.

In recent years, the second stage of labor has become an area of interest to a number of observers who have described divisions or phases with behavioral characteristics. Using a descriptive case study design, four normal nulliparous women in spontaneous second stage labor were videotaped from the occurrence of involuntary bearing-down efforts or the recognition of complete cervical dilation until birth. Analysis of these videotapes, the accompanying narrative transcripts, and uterine monitor tracings provided evidence that some behaviors changed over the progression of the second stage. These changes could be divided into three behavioral phases that the nurse/midwife can identify in order to recognize the typical pattern of progression and possible deviations from normal.

Two synthetic, water-soluble porphyrins, tetra-4N-methyl-pyridyl porphyrin (T4NMPyP) and tetra-N,N,N-trimethylanilinium porphyrin (TMAnP), and their indium(III) complexes have been isotopically substituted for evaluation by solid-state NMR of their adsorption to melanin. Methyl carbons on the pyridyl and anilinium nitrogens on the periphery of the porphyrin are one site of substitution; the four equivalent meso carbons in the porphyrin ring are the second. Chemical shifts and line widths of the carbon resonances in the bulk porphyrins change after they are adsorbed on synthetic and natural melanins. These changes may be related to the predominant binding interactions involved in the adsorption process and suggest that chemisorption, involving strong interactions comparable to chemical bonds, occurs between charged groups in both ligand and substrate. Inhomogeneous line broadening of the resonances implies that variations in binding exist, which is in keeping with the known heterogeneous nature of the melanin polymer and the different steric demands of the porphyrin ligands. These solid-phase experiments illustrate the promise of NMR for elucidating information about the binding of soluble molecules to insoluble and structurally irregular biopolymers. Furthermore, they represent the first spectroscopic probe of the binding of cationic molecules to the biopolymer melanin in the solid state. Coupled with results from molecular modelling, they indicate that cationic porphyrins bind to melanin at similar sites.

The structure of the order parameter in superfluid 3 He mimics closely the analogous structure of the “metric” of the Universe. Since the superfluid may exist in several phases we can, using a magnetic field gradient, set up coherent phase boundaries in the superfluid which are the closest laboratory analogues we have to cosmological branes. We find that if we annihilate two such branes (an AB and a BA interface) then we find that the annihilation leaves relic defects in the superfluid texture. These results can help to “validate” those braneworld scenarios where brane annihilation is thought similarly to lead to the formation of topological defects such as cosmic strings.

Two studies were conducted to examine the long-term impact of parental divorce on beliefs about the self and others. In Study 1, college-aged children of divorce and students from intact families did not differ on 8 basic assumptions or on measures of depression. Those whose parents are divorced, however, were less optimistic about the success of their own future marriages. Assumptions about the benevolence of people best predicted the marital optimism of the parental divorce group, but not of the intact family group. In Study 2, assumptions about the benevolence of people were explored in terms of trust beliefs. College-aged children of divorce and a matched sample from intact homes differed only on marriage-related beliefs, not on generalized trust. Children of divorced reported less trust of a future spouse and were less optimistic about marriage. Exploratory analyses found that continuous conflict in family of origin adversely affected all levels of trust.

The phonological development of 145 children between the ages of 2 1/2 and 8 years was examined. Speech was assessed annually using a standardized articulation test and analyzed for the occurrence of both common and uncommon phonological processes. A marked decline in process usage was observed between the ages of 2 1/2 and 4 years and infrequent process usage was observed after the age of 4. Uncommon processes were used infrequently, even at 2 1/2 years. No sex differences were found. Race differences were found with respect to isolated processes.

The characteristics of caring nursing practice are often, by their very nature, hidden. If caring is to become a core value of the health care system, these caring characteristics need to be uncovered so that they can be taught, rewarded, and recognized as contributing to successful patient outcomes.

The eye is particularly vulnerable to damage from the phototoxic side effects of drugs since it is constantly subjected to ambient light. Presented here are several screens that can be used to determine the potential of drugs to cause light damage to the eye. These include a simple screen that takes into account the optical properties of the eye and the absorption spectra of the various drugs. This can be used to omit various drugs as potential photooxidants in the eye. In addition a second, more detailed screen is presented. This can be used to determine a) the quantitative potential for a drug to cause photooxidative damage in the eye, b) the mechanism by which it occurs and c) the in vivo verification of phototoxicity.

The control of emissions of oxides of nitrogen from resource recovery facilities is becoming an increasingly important consideration in environmental permitting of new facilities. California presently has strict emission standards in place and other states are considering such standards. This paper reviews the theory of solid fuel combustion, and NOx formation and control in the context of solid waste combustion. The paper further discusses available control technology and its application to facilities burning solid waste.

A field investigation into the effect of slurry seeding on the dry-matter yield and persistence of an Italian ryegrass sward was assessed over a 3-year period (1984–86) under a regime of three cuts per season combined with sheep grazing in early spring and late autumn. Results showed that slurry plus seed treatments produced up to 30% more herbage dry matter and a significantly higher tiller density than where no slurry or seed were used. Slurry application with and without seed also reduced the proportion of weed grasses (mainly Poa spp.) in the sward. It is concluded that slurry seeding is a useful technique for extending the productive life of an Italian ryegrass sward.

If alpha and alpha ' are one-parameter automorphism groups of a von Neumann algebra M, alpha ' is said to be a bounded perturbation of alpha if // alpha /sub t/'- alpha /sub t/// to O at t to O. The authors give a complete characterization of the bounded perturbations alpha ' of alpha . In particular, they show that if alpha can be implemented by a strongly continuous one-parameter group with self- adjoint generator (Hamiltonian) H, then alpha ' can be implemented in the same way and the corresponding Hamiltonian H' can be chosen to be of the form H'-VHV/sup -1/+h, where V is a unitary of M and h=h* epsilon M. (16 refs).

The effect of management on dry matter yield and persistence of eight cultivars was assessed over a 3-year period (1978–80) under integration of sheep grazing and simulated sheep grazing with cutting for conservation, and the two cutting frequencies used in the National List trials. A high correlation was obtained in the first and second harvest years between managements in respect of annual production, the ranking order of yield being similar for the range of cultivars. In the third harvest year yield correlation and persistence between sheep grazing and simulated sheep grazing was high and similar to previous years, but all other yield and persistence correlations were considerably reduced. A major effect of frequent cutting management used in the National List trials was the increase in the proportion of unsown grasses (mainly Poa spp.) in the swards.

Alternative routesfor theproduction of plates with a yield stress of about 450N/mm2 are discussed. A comparison is made between normalized, controlled-rolled, and quenched and tempered steels, withparticular attention beingpaid tofactors affecting theirproduction and use.

The diurnal relationship between xylem pressure potential and stem diameter in white oak (Quercusalba L.) resulted in a hysteresis loop on clear days where, for a given level of xylem pressure potential, the stem was thinner upon rehydration than during dehydration. Cloudy days complicated this pattern by forming a loop within the main loop. This additional loop was caused by the same factor which caused the main loop, the delayed reaction or lag between changes in stem diameter and xylem pressure potential. Both net assimilation rate and leaf surface resistance were closely linked and responded rapidly to changes in radiation. Hydroactive increases in leaf surface resistance were observed as xylem pressure potential decreased below −23 bars. A discussion of the relationship between stem diameter, radiation, leaf surface resistance, and xylem pressure potential is presented.

Scouting soybeans in Virginia is economically feasible with existing labor and insect treatment costs, present insect treatment practices, and at work efficiencies obtained in 2 years of study. In 1972, 36 fields averaging 23.9 acres were scouted for 4 weeks in Middlesex County at a cost of 7.2¢/acre/week. In 1973, 32 fields averaging 27.0 acres were scouted for 6 weeks in Virginia Beach at a cost of 5.5¢/acre/week. The percentage of insect control costs spent before insect populations reached levels at which Virginia Polytechnic Institute and State University recommends control was 87.2% in Middlesex County and 89.7% in Virginia Beach. Elimination of unnecessary control costs would have yielded net savings per dollar of outlay equal to $4.54 in 1972 and $3.13 in 1973.

In an era when it is generally believed that the acute Symptoms of schizophrenia can be controlled pharmacologically, the case of a young man who has remained almost continuously floridly psychotic for 13 years, despite treatment, is disquieting. Conventional psychiatrie treatment appears to be rendered impotent. It is in this context that it may be of interest to report a summary of the proceedings of a Special Problems Conference held at the Institute of Psychiatry on 18 February 1985 to discuss such a case.

The principles governing the standard range of normalized steels are well established, namely improved uniformity of properties compared with steels which finish rolling at random temperatures, and the use of low carbon fine grain steels where needed to meet requirements for ease of welding, strength, and notch toughness. This paper therefore, looks at the prospects of extending the range of notch toughness guarantees at low temperatures (below — 50 °G); the achievement of resistance to lamellar tearing where stresses are applied perpendicular to plate surfaces; and the response of steels to stress relieving procedures. In practice, steels exist to meet these situations, but the ability to predict their behaviour and to understand all the physical metallurgy involved, is incomplete and warrants further study as an aid towards avoiding unforeseen problems in production or service.

The place of the Dirac formalism in quantum theory is investigated using rigged Hilbert spaces. Emphasis is laid on the representation of observables by continuous linear operators and on the existence of sufficient eigenkets. Using the concept of labeled observables, a canonical procedure is given for constructing a rigged Hilbert space and the bra and ket spaces are constructed for nonrelativistic quantum systems of n interacting particles. Spectral theory is investigated in this framework and the results are compared with the Dirac formalism.

A parallel plate chamber and measuring system suitable for use with high-voltage X rays are described. Saturation and plate separation conditions were shown to be satisfactory for X rays and apparently so for gamma rays. Measurements of gamma rays in rontgens gave the equivalent of 1 mgm.-hr. at 1 cm. from a point source, 3·08 r. This result does not agree with previous “air wall” chamber experiments. An investigation of the discrepancy showed that the paths of recoil electrons were greater than the linear dimensions of the measuring system, and that the ionisation observed in an “air wall” chamber is a complex function of conditions unless the walls are of a thickness at least equal to the ranges of electrons produced by the radiation in them. It was found experimentally that the thick wall chamber has an equivalent air volume equal to its real volume for hard X rays. Measurements of gamma rays in rontgens gave as the equivalent of 1 mgm.-hr. at 1 cm. from a point source (0·5 mm. Pt. filter) 8·3 r. It ap...

A dosemeter is described suitable for use over a wide range of radiation qualities and dosage rates. Measurements with point and ring sources indicate that owing to compensation of absorption and scatter the distribution of radiation in a scattering medium is very similar to that in air; when the radium is on the surface of the medium the compensation is incomplete, and there is a small apparent absorption. Isodose curves are given for a simple ring source in air and when placed on the surface of a scattering mass, and it is shown that in air the measured distributions agree well with the calculated values.

An attempt has been made to overcome some of the defects of the standard methods of mechanical testing of materials. The new method, in which the deformation is brought about by attaching the specimen to a substrate, shows that when the final mechanical failure occurs, continuity is preceded by a region of disturbed flow in which the flow lines appear as a pattern of remarkable regularity, the direction of which is not that of maximum shear. Materials such as dry powders, pastes, polymers and vacuum-deposited metals have been studied and show unexpected common features, e.g. fatigue and relaxation of work hardening by vibrations.

A description is given of generator and tube for use up to 400 KV. The protection of the observers is discussed. Experiments have been made on the variation of output with voltage and the copper filters possible at different potentials. The absorption of the rays in copper and variation of half-value layer is given. Measurements have been made in a water phantom on “back scatter,” distribution of radiation throughout the water mass, and the effects of variation of field size. It is shown that “back scatter” reaches a maximum for a given quality of radiation and that the variation of percentage depth dose with change of average wave-length is small. Some theoretical considerations are briefly mentioned.

The paper describes measurements of the ionisation produced in air by radium sources. Various errors such as scattering from the wall of the ionisation chamber and room, finite size of chamber and source, atomic number of walls of chamber, etc., are discussed in detail. A carefully standardised measuring system is described, and the results of measurements with carbon, magnesium, lead, and paraffin wax chambers are given. A section of the paper is devoted to questions of accurate measurement of radium sources, particularly in relation to the errors which may arise from the use of various types of ionisation chamber. It is concluded that the total charge set free per cubic centimetre of air at N.T.P., at I cm. distance from a point source of I mg. Ra element filtered with 0·5 mm. Pt, is 8·3 electrostatic units per hour.

Three methods of making aluminium soaps are described, and one, the 'metathetic reaction between a sodium soap solution and an aluminium salt solution, is discussed in detail. The effect of variations in manufacturing technique upon the gelling characteristics of the product is considered. Recent work by various investigators on the structure of aluminium soaps is reviewed, particularly in relation to the effect of structure and peptizers upon the gelling property in hydrocarbon solvents. Mention is made of the more important methods of moisture determination and results obtained by the use of the Karl Fischer reagent are quoted.