A stable cell line with a proportion of cells persistently infected with bovine viral diarrhoea virus

Bovine turbinate (BTu) and lamb testis (LT) cell lines persistently infected with bovine viral diarrhoea virus (BVDV) arose as a result of a single change of medium containing commercial foetal calf serum. Infected cells comprise 30% and 50% respectively, of the total cell population, determined by immunohistochemical staining. The ratio of positive cells has remained unchanged during successive passages. Characterization of the persistently-infected BTu cells (BTuI) showed that only full length viral RNA was detected by northern blot hybridisation, indicating that DI particles were not involved. Secreted and intracellular virus from these cells was fully infectious for fresh BTu and LT cells. The BTuI cell line was fully permissive for a cytopathic BVDV isolate and a bovine herpesvirus, but non-permissive for two non-cytopathic BVDV isolates. Attempts to induce the permissive state in the BVDV-negative cells of the BTuI culture by treatment with actinomycin D and 5'-aza-cytidine failed. These cells provide a convenient model to study aspects of BVDV pathogenesis and replication.     

An investigation of the implicit control of the processing of negative pictures.

The implicit control of emotion processing was investigated by varying encoding instructions for both negative and neutral pictures while measuring psychophysiological responses. Participants made comparative judgments about consecutive pictures for blocks of neutral or negative content. The highly specified judgment task was designed to minimize variance in the implementation of implicit control of processing. Affective modulation of startle amplitude was significantly reduced during judgments involving nonnegative content (how "planned" an image was compared to its predecessor), compared to those that involved negative content (how "frightening" an image was compared to its predecessor), indicating successful implicit control of processing. The more attenuated affect modulation was, the less anxious individuals became during the task, suggesting that the implicit control of emotion processing is significantly associated with emotional experience. These data provide convergent evidence for a companion neuroimaging study because of the similar neural substrates thought to underlie affective modulation of startle. This supports the view that higher-level top-down pathways modulate activation of the amygdala. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Levels of specificity of autobiographical memories and of biographical memories of the deceased in bereaved individuals with and without complicated grief.

Traumatized individuals experiencing posttraumatic stress have difficulty retrieving specific autobiographical memories to cue words on the Autobiographical Memory Test (AMT; J. M. G. Williams & K. Broadbent, 1986). This may represent a generalized, functional avoidance of the personal past. However, such individuals also often report specific intrusive memories of their trauma in the day-to-day. This raises the possibility that memories tied to the source of the person's distress are immune to this putative avoidance process. This was investigated in bereaved individuals with complicated grief (CG) who reported intrusive, specific memories from the life of their deceased loved one, and matched bereaved controls without CG. Participants performed the AMT and two Biographical Memory Tests (BMTs), cueing memories from the life of the deceased (BMT-Deceased) and from a living significant other (BMT-Living). To negative word cues, the CG group showed reduced specificity for the AMT and BMT-Living, relative to controls, but this effect was reversed on the BMT-Deceased. These data support the proposal that memories tied to the source of an individual's distress are immune to the processes that underlie the standard reduced specificity effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

β-phase formation in a crosslinkable poly(9,9-dihexylfluorene)

The synthesis of a crosslinkable poly(9,9-dihexylfluorene) derivative is reported. Vinyl ether moieties allow for photolithographic patterning, resulting in an immiscible polyfluorene network, which enables subsequent wet thin-film processing. The metastable β-phase morphology, inherent to most polyfluorene homopolymers, can be induced in this crosslinkable polymer. This is verified by optical spectroscopy, X-ray diffraction and by thermal analysis. The β-phase in polyfluorenes is of interest due to its superior optical and electrical characteristics compared to the amorphous phase. Here, amplified stimulated emission is studied. Surprisingly, the β-phase polymer exhibits higher emission thresholds than the amorphous analogue.     

An analysis of transfer along a continuum.

10 white carneaux pigeons trained on an easy wavelength discrimination subsequently performed more accurately on a hard wavelength discrimination than did 10 controls trained on the hard problem from the outset. The effect was not a simple consequence of learning an easy problem, for a 3rd group (N=10), initially trained on the hard wavelength discrimination but with a 2nd relevant dimension added, performed no more accurately than controls. Nor was it due to a greater difference in response strengths to the stimuli of the hard problem, since a 4th group (N=10), initially trained on the reversal of the easy problem, eventually performed more accurately than controls. A 2nd experiment with 20 white carneaux pigeons of the same age, further disconfirmed this 2nd analysis, leaving it probable that the basic result is partly a consequence of the strengthening of attention to the relevant dimension. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)