Backscattered electron SEM imaging of cells and determination of the information depth.

Backscattered electron imaging of HT29 colon carcinoma cells in a scanning electron microscope was studied. Thin cell sections were placed on indium-tin-oxide-coated glass slides, which is a promising substrate material for correlative light and electron microscopy. The ultrastructure of HT29 colon carcinoma cells was imaged without poststaining by exploiting the high chemical sensitivity of backscattered electrons. Optimum primary electron energies for backscattered electron imaging were determined which depend on the section thickness. Charging effects in the vicinity of the SiO2 nanoparticles contained in cell sections could be clarified by placing cell sections on different substrates. Moreover, a method is presented for information depth determination of backscattered electrons which is based on the imaging of subsurface nanoparticles embedded by the cells.

Altered subcortical emotional salience processing differentiates Parkinson's patients with and without psychotic symptoms.

OBJECTIVE: Current research does not provide a clear explanation for why some patients with Parkinson's Disease (PD) develop psychotic symptoms. The 'aberrant salience hypothesis' of psychosis has been influential and proposes that dopaminergic dysregulation leads to inappropriate attribution of salience to irrelevant/non-informative stimuli, facilitating the formation of hallucinations and delusions. The aim of this study is to investigate whether non-motivational salience is altered in PD patients and possibly linked to the development of psychotic symptoms. METHODS: We investigated salience processing in 14 PD patients with psychotic symptoms, 23 PD patients without psychotic symptoms and 19 healthy controls. All patients were on dopaminergic medication for their PD. We examined emotional salience using a visual oddball fMRI paradigm that has been used to investigate early stages of schizophrenia spectrum psychosis, controlling for resting cerebral blood flow as assessed with arterial spin labelling fMRI. RESULTS: We found significant differences between patient groups in brain responses to emotional salience. PD patients with psychotic symptoms had enhanced brain responses in the striatum, dopaminergic midbrain, hippocampus and amygdala compared to patients without psychotic symptoms. PD patients with psychotic symptoms showed significant correlations between the levels of dopaminergic drugs they were taking and BOLD signalling, as well as psychotic symptom scores. CONCLUSION: Our study suggests that enhanced signalling in the striatum, dopaminergic midbrain, the hippocampus and amygdala is associated with the development of psychotic symptoms in PD, in line with that proposed in the 'aberrant salience hypothesis' of psychosis in schizophrenia.

Magma Beneath Yellowstone National park.

The Yellowstone plateau volcanic field is less than 2 million years old, lies in a region of intense tectonic and hydrothermal activity, and probably has the potential for further volcanic activity. The youngest of three volcanic cycles in the field climaxed 600,000 years ago with a voluminous ashflow eruption and the collapse of two contiguous cauldron blocks. Doming 150,000 years ago, followed by voluminous rhyolitic extrusions as recently as 70,000 years ago, and high convective heat flow at present indicate that the latest phase of volcanism may represent a new magmatic insurgence. These observations, coupled with (i) localized postglacial arcuate faulting beyond the northeast margin of the Yellowstone caldera, (ii) a major gravity low with steep bounding gradients and an amplitude regionally atypical for the elevation of the plateau, (iii) an aeromagnetic low reflecting extensive hydrothermal alteration and possibly indicating the presence of shallow material above its Curie temperature, (iv) only minor shallow seismicity within the caldera (in contrast to a high level of activity in some areas immediately outside), (v) attenuation and change of character of seismic waves crossing the caldera area, and (vi) a strong azimuthal pattern of teleseismic P-wave delays, strongly suggest that a body composed at least partly of magma underlies the region of the rhyolite plateau, including the Tertiary volcanics immediately to its northeast. The Yellowstone field represents the active end of a system of similar volcanic foci that has migrated progressively northeastward for 15 million years along the trace of the eastern Snake River Plain (8). Regional aeromagnetic patterns suggest that this course was guided by the structure of the Precambrian basement. If, as suggested by several investigators (24), the Yellowstone magma body marks a contemporary deep mantle plume, this plume, in its motion relative to the North American plate, would appear to be "navigating" along a fundamental structure in the relatively shallow and brittle lithosphere overhead. The concept that a northeastwardpropagating major crustal fracture controls the migration path of the major foci of volcanisim is at least equally favored by existing data, as Smith et al. (19) noted.

Rotation of a strongly magnetized hydrogen plasma column determined from an asymmetric Balmer-beta spectral line with two radiating distributions.

A potential buildup in front of a magnetized cascaded arc hydrogen plasma source is explored via E x B rotation and plate potential measurements. Plasma rotation approaches thermal speeds with maximum velocities of 10 km/s. The diagnostic for plasma rotation is optical emission spectroscopy on the Balmer-beta line. Asymmetric spectra are observed. A detailed consideration is given on the interpretation of such spectra with a two distribution model. This consideration includes radial dependence of emission determined by Abel inversion of the lateral intensity profile. Spectrum analysis is performed considering Doppler shift, Doppler broadening, Stark broadening, and Stark splitting.

A new compact solid-state neutral particle analyser at ASDEX Upgrade: Setup and physics modeling.

At ASDEX Upgrade (AUG), a new compact solid-state detector has been installed to measure the energy spectrum of fast neutrals based on the principle described by Shinohara et al. [Rev. Sci. Instrum. 75, 3640 (2004)]. The diagnostic relies on the usual charge exchange of supra-thermal fast-ions with neutrals in the plasma. Therefore, the measured energy spectra directly correspond to those of confined fast-ions with a pitch angle defined by the line of sight of the detector. Experiments in AUG showed the good signal to noise characteristics of the detector. It is energy calibrated and can measure energies of 40-200 keV with count rates of up to 140 kcps. The detector has an active view on one of the heating beams. The heating beam increases the neutral density locally; thereby, information about the central fast-ion velocity distribution is obtained. The measured fluxes are modeled with a newly developed module for the 3D Monte Carlo code F90FIDASIM [Geiger et al., Plasma Phys. Controlled Fusion 53, 65010 (2011)]. The modeling allows to distinguish between the active (beam) and passive contributions to the signal. Thereby, the birth profile of the measured fast neutrals can be reconstructed. This model reproduces the measured energy spectra with good accuracy when the passive contribution is taken into account.

Viral diseases of the skin, 1975: a 25-year perspective.

Most of the major advances in modern virology during the past 25 years have been due principally to the development of refined laboratory techniques and tools and have provided a fund of new knowledge and information about the nature of viral infection and pathogenesis. One group of viruses of interest to dermatologists, the herpesviruses, is undergoing intensive biochemical investigation to determine whether it is carcinogenic. As a result of the success of the World Health Organization's campaign to eradicate smallpox, it is predicted that by the end of 1976, smallpox will have been eradicated. Other viruses of dermatologic interest which are now being studied include the agents of warts, molluscum contagiosum, cat-scratch disease, and enteroviruses. Current research in the field of viral chemotherapy may provide the basis for successfully treating these diseases in the future.

Cooperative evaluation of human tumor chemosensitivity in the soft-agar assay and its clinical correlations.

In supporting the human-tumor cloning effort of the Southwest Oncology Group, we conducted an independent retrospective study to evaluate the clinical correlations of the soft-agar colony-forming assay developed by Hamburger and Salmon (1977). This study was made with the cooperation of 76 clinicians and 11 hospitals in Greater New Orleans. In a 10-month trial (July 1982 to May 1983), we received 134 human tumors of 26 classifications and achieved 76% success in colony growth from 122 plated samples. Retrospective correlations between the in vitro chemosensitivity of tumor colonies and clinical drug responses were made possible in 31% of the patients. Evaluation of 45 in vitro and in vivo associations indicated a combined sensitivity of 0.65 and a specificity of 0.68 for the assay. Technical refinements and the selectivity of the assay are discussed.

Pharmacologic assessment of regimen chemosensitivity in the soft-agar assay: effect of oxygen on human tumors.

The influence of oxygen on the growth and the in vitro chemosensitivity of human tumor cells was studied in the soft-agar assay. Tumor cells of pancreatic and ovarian origin prefer a reduced oxygen atmosphere for colony formation, whereas those of pulmonary origin grow better in 20% oxygen. Depending on the physiologic oxygen tension and the histologic origin of a particular cancer type, the in vitro chemosensitivity of many drug obtained with the conventional culture system could be inadequately assessed. The in vitro responses of tumor cells to combinations of drugs were measured by the regimen efficacy index (REI) method. The REI delineates the possible regimen enhancement or regimen default based on the in vitro chemosensitivity of the individual agents tested in the assay. In vitro regimen enhancement was observed only in ascites incubated in a reduced oxygen atmosphere with two-drug combinations. However, regardless of the oxygen gradients used, regimen default was seen in cancer cells of solid tumors treated with all combinations of drugs tested. This study suggests further investigation on the effects of oxygen in the soft-agar assay, and proposes the novel use of the REI method for evaluating the in vitro regimen chemosensitivity of human tumor cells.

Failure of lysine in frequently recurrent herpes simplex infection. Treatment and prophylaxis.

Lysine has been claimed to be effective in the treatment and prevention of episodes of recurrent herpes simplex (HS) infection. We carried out a double-blind, placebo-controlled trial of oral lysine hydrochloride therapy (400 mg, three times a day) in a group of 21 patients in good general health with a history of frequently recurring infection. Using our measures of episode frequency, duration, and severity, we were unable to detect any substantial benefit of lysine therapy either as a treatment for episodes in progress or as a prophylactic drug for the prevention of recurrences. We conclude that it is unlikely that lysine improves frequently recurrent HS infections in the majority of patients.

Antithrombotic efficacy of single subcutaneous administration of a recombinant nematode anticoagulant peptide (rNAP5) in a canine model of coronary artery thrombolysis.

We examined the adjunctive benefit of recombinant nematode anticoagulant peptide (rNAP5), a factor Xa inhibitor, in a canine model of recombinant (rt)-PA-induced thrombolysis. In anesthetized dogs, a stable occlusive thrombus was formed by electrolytic injury of the vessel wall, after which the animals were administered rt-PA (1.44 mg/kg, i.v.) and rNAP5 (0.1 mg/kg, s.c.: n=13), or rt-PA plus vehicle (1-2 ml, s.c.; n=13). Hemodynamic and coagulation parameters were monitored for 360 minutes. Single subcutaneous administration of rNAP5 resulted in a prolonged and sustained increase in the activated partial thromboplastin time (>100-fold), whereas prothrombin time was unchanged. The template bleeding time was not altered significantly throughout the protocol (maximum 1.4-fold). The incidence of reperfusion was similar in the two groups with a trend toward faster reperfusion in the rNAP5 group (34+/-4 minutes) compared to the vehicle group (63+/-15 minutes; p=0.07). After reperfusion, 80% of the vessels in the vehicle group reoccluded, whereas only 14% of vessels reoccluded in the rNAP5-treated group. Times to reocclusion were 65+/-21 minutes and 221+/-28 minutes, respectively (p<0.05). Single subcutaneous administration of rNAP5 sustained the coronary artery blood flow after reperfusion, such that at the end of protocol the flow was 47% of the preocclusion value as compared to the vehicle group in which the flow was 11% (p<0.05). Cyclic flow reductions were most prominent during rt-PA-induced reperfusion and were similar in both groups. The results indicate that a single subcutaneous administration of rNAP5 provides a sustained antithrombotic effect in maintaining the coronary artery patency during rt-PA-induced thrombolysis.

Water management for controlling the breeding of Anopheles mosquitoes in rice irrigation schemes in Kenya.

An experiment to assess the impact of intermittent irrigation on Anopheles larval populations, rice yields and water use was conducted in the Mwea rice irrigation scheme in Kenya. Four water regimes including intermittent irrigation were tested in a complete randomized block experimental design. Intermittent irrigation was carried out on a weekly schedule, with flooded conditions from Saturday through Tuesday morning. Larval sampling at each plot was conducted every Monday and prior to draining of intermittently irrigated subplots on Tuesday. All the adult anopheline mosquitoes emerging from larvae collected in the experimental plots were identified as being An. arabiensis. By far the highest numbers of An. arabiensis 1st instar larvae were found in the intermittently irrigated subplots, indicating that the water regime provided the most attractive environment for egg laying. However, the ratio between the 4th and 1st instar larvae in the subplots was only 0.08, indicating very low survival rates. In contrast, the 4th/1st instar ratio for subplots with other water management regimes ranged between 0.27 and 0.68, suggesting a correspondingly higher survival than observed with intermittent irrigation. The total number of 4th instars was almost the same in the intermittently irrigated subplots and the irrigation system normally practised by the farmers. The failure to eliminate larval development up to the 4th instar in the former method was attributed to residual pools of water. Larval abundance fluctuated throughout the 12-week sampling period. The highest larval densities were recorded in the 3 weeks after transplanting the rice seedlings. Afterwards, larval numbers dropped dramatically as the height of rice plants increased. Rice yields at harvest did not show statistically significant differences among subplots with different water regimes. The average yield per hectare ranged from 4.8-5.3 metric tonnes. The average daily water percolation/seepage rate was 3.6 mm and did not significantly differ among different water management regimes. Further research is necessary to, among other things, determine whether rice yields could be increased by having flooded and drained intervals that were different from those used in this study. It would likewise be important to assess on a wider scale the feasibility of implementing intermittent irrigation with respect to farmer acceptance and required changes in irrigation system design and management.

Isolation of feline leukemia virus from clinical specimens.

Specimens obtained from feline leukemia virus (FeLV)-positive cats were examined for infectious FeLV. Feline leukemia virus was detected by a focus-forming assay and confirmed by florescent antibody. Techniques of sample processing were evaluated and adjusted for optimum detection of FeLV. Low levels of FeLV were detected in 2 of 10 oral samples; however, the majority of these samples (17 of 27 tested) produced cytopathic effects in tissue culture which prevented Fe LV detection. Three of 24 urine samples and 1 of 20 rectal specimens were positive for FeLV. One milk sample contained high levels of FeLV.

Reflections on the special senses in relation to the development of affect with special emphasis on blindness.

In congenital blindness, the absence of vision can be compensated for by the utilization of the tactile and auditory senses, resulting in normal affect and ego development. Some of the major problems in the way of such compensation were noted. Adventitious blindness produces disruption of ego functions, with severe affect manifestations, notably grief and mourning reactions and actual dependency. The factors favoring successful or unsuccessful resolution of mourning and restoration of normal ego functions were indicated.

Flow shear stabilization of rotating plasmas due to the Coriolis effect.

A radially decreasing toroidal rotation frequency can have a stabilizing effect on nonaxisymmetric magnetohydrodynamic (MHD) instabilities. We show that this is a consequence of the Coriolis effect that induces a restoring pressure gradient force when plasma is perturbed radially. In a rotating cylindrical plasma, this Coriolis-pressure effect is canceled by the centrifugal effect responsible for the magnetorotational instability. In a magnetically confined toroidal plasma, a large aspect ratio expansion shows that only half of the effect is canceled. This analytical result is confirmed by numerical computations. When the plasma rotates faster toroidally in the core than near the edge, the effect can contribute to the formation of transport barriers by stabilizing MHD instabilities.

Object wave reconstruction by phase-plate transmission electron microscopy.

A method is described for the reconstruction of the amplitude and phase of the object exit wave function by phase-plate transmission electron microscopy. The proposed method can be considered as in-line holography and requires three images, taken with different phase shifts between undiffracted and diffracted electrons induced by a suitable phase-shifting device. The proposed method is applicable for arbitrary object exit wave functions and non-linear image formation. Verification of the method is performed for examples of a simulated crystalline object wave function and a wave function acquired with off-axis holography. The impact of noise on the reconstruction of the wave function is investigated.