Olfactory basis of cannibalism in grasshoppers (Orthoptera: Acrididae): II. field assessment of attractants

The responses of rangeland grasshoppers to biologically and historically derived attractants were studied in a shortgrass prairie in southeastern Wyoming in July 1990. Seven long-chain fatty acids (C₁₄–C₂₀: singly and in combination), grasshopper cadavers, molasses, fruit extracts, and chloroform (solvent control) were tested. Each attractant was applied to filter paper and placed in an arena delimited by a 0.10-m² aluminum ring. Grasshoppers were most attracted to linoleic and linolenic acids, with significantly more grasshoppers found in these arenas than in those of the controls or other attractants. These two fatty acids alone and in combination were more attractive at 1 grasshopper equivalent (GE) than at 5 GE. The seed bug,Lygaeus kalmii Stål, and five species of ants were also attracted to these two fatty acids. Molasses had significantly more grasshoppers on the filter paper than did the other attractants, but molasses had significantly fewer grasshoppers in the arena than the fatty acids. Fruit extracts were not effective at attracting grasshoppers. Water extracts of cadavers attracted significantly more grasshoppers to the bait than did chloroform extracts. Because the assayed grasshopper community was dominated by the Gomphocerinae (a subfamily that includes many pest species that do not readily consume wheat bran bait), it may be possible to use fatty acids in conjunction with insecticidal bran baits for increased control of rangeland grasshoppers.     

Analysis of mammographic density and breast cancer risk from digitized mammograms

To evaluate the association between mammographic density and breast cancer risk, a simple, observer-assisted technique called interactive thresholding was developed that allows reliable quantitative assessment of mammographic density with use of a computer workstation. Use of this technique helps confirm that mammographic density is one of the strongest risk factors for breast cancer and is present in a large proportion of breast cancer cases. The strong relationship between mammographic density and breast cancer risk suggests that the causes of breast cancer may be better understood by identifying the factors associated with mammographically dense tissue and determining how such tissue changes as these factors vary. Furthermore, because it can be modified, mammographic density may also be a good vehicle for the development and monitoring of potential preventive strategies. Areas of ongoing investigation include evaluating a potential genetic component of mammographic density by comparing density measurements in twins and understanding changes in density relative to age, menopausal status, exogenous hormone use, and exposure to environmental carcinogens. In addition, work is ongoing to establish measurements from imaging modalities other than mammography and to relate these measurements directly to breast cancer risk.     

The clinical outcome of preterm premature rupture of membranes in twin versus singleton pregnancies

Initial findings of panic disorder as an independent risk factor for suicidal ideation and behavior could not be replicated in studies with psychiatric patients. Instead, it was concluded that panic and anxiety disorders are risk factors when they co-occur with a primary mood disorder. In the present study, the effect of diagnostic comorbidity on rates of suicidality is analyzed on depressive inpatients treated at special depression wards. In a prospective follow-up study, suicidality and anxiety were assessed by means of a modified German version of the Diagnostic Interview Schedule (DIS). Patients with the symptom of panic attacks showed significantly elevated lifetime prevalence rates of suicidality in comparison with patients who did not report this additional symptom. For the follow-up period, however, there were no significant differences between these two groups. According to these results, the group of depressives with additional panic attacks is not more at risk for suicidal behavior, after being treated in an adequate manner.     

Quality assurance in pharmaceutical powder processing: Current developments

Pharmacopoeia1 requirements relating to standardization of the physical performance of oral dosage forms containing powders are usually limited to tests on the final product.

Such tests are aimed at ensuring that all tablets or capsules have the correct, nominal, drug content and that the drug is released into solution within a specified time. Whilst dissolution or disintegration test to assess drug release can only be carried out on a finished dosage form, content uniformity tests currently carried out on tablets or capsules alone could also be usefully carried out earlier on component powders at different stages during processing. The aim of developing a quality assurance procedure for quantifying the homogeneity of powders prior to tablet compaction or encapsulation would be to pin-point more precisely the part of a process where content uniformity problems arise. Secondly, a good quality assurance procedure would provide full mechanistic information about the behaviour of a given powder system, so that appropriate remedies could be applied.

Eleven different methods of testing homogeneity of powder mixes have been cited in pharmaceutically oriented literature and these will be reviewed in terms of their usefulness as routine quality assurance procedures for drug content uniformity. Of these 11 methods, 2 test methods were considered to be especially useful: one based on a flow test and the other on vibration analysis. This techniques has been validated using a complete vibration analysis and testing rig under conditions encountered during routine powder processing.

It would be desirable to see standard powder mixes tested on apparatus of the same design in different laboratories as a means of assessing the reproducibility of the proposed quality assurance method when used by different personnel.     

Inelastic light scattering from electronic excitations in deep-etched quantum dots and wires

Resonant Raman spectroscopy of modulation-doped GaAs/AlGaAs multiple quantum well dots and wires is reported. Deep etching with a SiCl₄ reactive ion etching process achieved an excellent aspect ratio (>10:1) and low surface damage for dots and wires of sizes in the range 60–250 nm. A rich spectrum of single particle excitations was observed at Raman shifts in the range 1–35 meV for both dots and wires. Sharp resonances were found for the Raman intensities. The electronic scattering in wires exhibits distinct polarization properties in agreement with theoretical predictions and the spin density excitation energies are in reasonable agreement with Hartree approximation calculations. The dispersion of the intrasubband plasmon collective mode in 60 nm wires has been determined. The excitations in dots show a systematic shift to higher energy with decreasing dot diameter consistent with increased confinement. Magneto-Raman scattering from dot samples was also investigated at magnetic fields up to 12 T and the excitation spectra show level splitting, level crossing and mode softening with increasing magnetic field.     

Tracheal involvement in Wegener's granulomatosis: evaluation using spiral CT

OBJECTIVE: To describe the computed tomography (CT) appearances of tracheal stenosis in Wegener's granulomatosis (WG) and to assess the additional value of reformatted images. PATIENTS AND METHODS: Ten patients with tracheal involvement by WG were assessed with spiral CT and both coronal and three-dimensional surface shaded images were generated. Fibreoptic bronchoscopy was also performed in all patients. RESULTS: Ninety per cent of lesions were situated in the subglottic region. In all cases there was circumferential mucosal thickening, in nine cases extending over a relatively short distance (mean 2.4 cm). The degree of narrowing of the axial luminal diameter ranged from 23% to 100%. In three patients there was contiguous involvement of the vocal cords evident on CT, two further cases with mild vocal cord inflammation were identified bronchoscopically. Other CT findings included mucosal irregularity and ulceration (50%), and involvement of the tracheal cartilages (20%). CONCLUSION: Wegener's granulomatosis may involve the trachea with resultant stenosis. Spiral CT is an easily performed, non-invasive technique which provides accurate assessment of tracheal lesions and is complementary to bronchoscopy. The main additional advantage of coronal reformatted images was our added confidence in defining the upper and lower limits of lesions and in the evaluation of vocal cord involvement.     

Strength of silicone breast implants

Rupture and leakage are recognized problems associated with silicone breast implants. Data are scarce about the durability of the silicone shell, and the life span of this device is unknown. The purpose of this study was to investigate the strength of silicone breast implants. Thirty implant shells were subjected to mechanical testing. Twenty-nine of the shells were tested after explanation, and one unused implant served as a control to validate the testing method. Implantation time varied from 4 months to 20 years, and all shells were tested, regardless of condition. Fourteen implant shells were intact, eight were leaking, and seven were ruptured. All ruptured implants had been in place for 10 years or longer. The breaking force of all excised shell specimens ranged from 2.6 to 22.4 N (0.6 to 5.0 lb.). Specimens from the control "high performance" shell required 15.5 to 25.6 N (3.5 to 5.8 lb) of force to fail. The weakest group was from thin-shelled implants between 10 and 16 years of age. More than half these specimens failed with less than 1 lb of force. The average breaking force of ruptured shell material was less than that of intact shells. A comparison of strength data in this study with manufacturers' data suggests that breaking force is dependent on implant type, shell thickness, and implantation time.     

Attentional systems and the allocation of cerebral resources in reading and grammatical tasks

To evaluate the possible role of attentional centers as modulators of neural networks that mediate visual tasks involving reading and grammatical manipulations of verbs, we measured cerebral blood flow (CBF) using positron emission tomography (PET), and reaction times as subjects read verbs, "nonce verbs" such as jelt or brep, and formed past tenses of regular, irregular and nonce verbs after viewing their stems. Statistical parametric maps (SPMs) showed significant activation of the pulvinar in the read verb irregular, and generate nonce past tense tasks, compared to rest. This was confirmed by a post hoc ANOVA of CBF values from a discrete locus in the pulvinar (p = .0000417). Functional links between the pulvinar and other brain regions were shown by high correlations of CBF in the pulvinar with CBF in brain regions known to have anatomical connections to the pulvinar, particularly those mediating vision. There was also a significant relationship between task-specific reaction times and rest minus task CBF differences in a multiple regression analysis that included CBF values from the pulvinar, superior colliculus plus reticular formation, and the anterior cingulate, known attentional centers (p = .021, r2 = 0.99). Regression analyses relating reaction time to the amount of brain activated (pixels in the SPMs) and the degree of activation of the pixels (mean Z score) yielded p values of .078 and .074, respectively. Our data provide direct experimental evidence to support the hypothesis that attentional centers are activated in proportion to the complexity of visually mediated language tasks and that the centers that mediate attention modulate the activity of task-specific neural networks.     

Detection and differentiation of breast cancer using neural classifiers with first warning thermal sensors

Breast cancer occurs when cells in the breast begin to grow out of control and invade nearby tissues or spread throughout the body. It is one of the leading causes of death in women. Cancer development appears to generate an increase in the temperature on the breast surface. The limitations of mammography as a screening modality, especially in young women with dense breasts, necessitated the development of novel and more effective screening strategies with high sensitivity and specificity. The aim of this study was to evaluate the feasibility of discrete thermal data (DTD) as a potential tool for the early detection of the breast cancer.Our protocol uses 1170, 16-sensor data collected from 54 individuals consisting of three different kinds of breast conditions: namely, normal, benign and cancerous breast. We compared two different kinds of neural network classifiers: the feedforward neural network and the radial basis function classifier. Temperature data from the 16 temperature sensors on the surface of the two breasts (eight sensors on each side) are fed as input to the classifiers. We demonstrated a sensitivity of 84% and 91% for these classifiers (feedforward and radial basis function, respectively) with a specificity of 100%. Our classifying systems are ready to run on large data sets.     

Sexual dimorphism in the face of Australopithecus africanus

Recently discovered crania of Australopithecus africanus from Sterkfontein Member 4 and Makapansgat enlarge the size range of the species and encourage a reappraisal of both the degree and pattern of sexual dimorphism. Resampling methodology (bootstrapping) is used here to establish that A. africanus has a greater craniofacial size range than chimpanzees or modern humans, a range which is best attributed to a moderately high degree of sexual dimorphism. Compared to other fossil hominins, this variation is similar to that of Homo habilis (sensu lato) but less than that of A. boisei. The finding of moderately high dimorphism is corroborated by a CV-based estimate and ratios between those specimens considered to be male and those considered to be female. Inferences about the pattern of craniofacial dimorphism in the A. africanus face currently rely on the relationship of morphology and size. Larger specimens, particularly Stw 505, show prominent superciliary eminences and glabellar regions, but in features related in part to canine size, such as the curvature of the infraorbital surface, large and small specimens of A. africanus are similar. In this respect, the pattern resembles that of modern humans more so than chimpanzees or lowland gorillas. A. africanus may also show novel patterns of sexual dimorphism when compared to extant hominines, such as in the form of the anterior pillar. However, males of the species do not exhibit characteristics of more derived hominins, such as A. robustus.