CD4 T cells are not thought to play a significant role in generating an effective primary CD8 T cell response to most viral infections. We have challenged this view by demonstrating that ...antigen-specific CD4 T cells can indeed suppress the proliferation of antigen-specific naive CD8 T cells in response to low doses of vesicular stomatitis virus. This finding is in contrast to the established observations that at high antigen loads CD4 T cells play little role in generating CD8 T cell responses, and that in non-infectious model systems CD4 T cells actually help the CD8 T cell response. Our results suggest that at low infectious doses, CD4 T cells play a much larger role in controlling infections than previously appreciated.
At 14 degree C, standard metabolic rate (75.1 mg O sub(2)h super(-1)kg super(-1)), routine metabolic rate (108.8 mg O sub(2)h super(-1)kg super(-1)), active metabolic rate (c. 380 mg O sub(2)h ...super(-1)kg super(-1)), critical swimming speed (U sub(crit)1.7 BL s super(-1)), heart rate 47 min super(-1)), dorsal aortic pressure (3.2 kPa) and ventilation frequency (63 min super(-1)) for triploid brown trout Salmo trutta were within the ranges reported for diploid brown trout and other salmonids at the same temperature. During prolonged swimming (c. 80%U sub(crit)), cardiac output increased by 2.3-fold due to increases in heart rate (1.8-fold) and stroke volume (1.2-fold). At 18 degree C, although standard and routine metabolic rates, as well as resting heart rate and ventilation frequency increased significantly, active metabolic rate and certain cardiorespiratory variables during exercise did not differ from those values for fish acclimated to 14 degree C. As a result, factorial metabolic scope was reduced (2.93-fold at 18 degree C v. 5.13-fold at 14 degree C). Therefore, it is concluded that cardiorespiratory performance in triploid brown trout was not unusual at 18 degree C, but that reduced factorial metabolic scope may be a contributing factor to the mortality observed in triploid brown trout at temperatures near 18 degree C. Copyright 2002 The Fisheries Society of the British Isles
La Convention citoyenne pour le climat (CCC) constitue la première expérience de démocratie délibérative au niveau national en France, elle est, en cela, inédite. Certes, elle a été précédée par des ...expériences équivalentes au niveau local, mais elle demeure, pour l’instant, la plus importante du fait de son ampleur et de l’intérêt qu’elle a suscité. Par ailleurs, elle doit être distinguée d’expériences de démocratie participative qui ont lieu régulièrement sur le territoire français depuis d...
Aim Faecal incontinence is a significant source of distress, and a permanent stoma is frequently offered to these patients. The antegrade colonic enema (ACE) procedure is an alternative approach to ...treat faecal incontinence. The long‐term outcome remains unknown in adults with faecal incontinence. The aim of this study was to evaluate the long‐term results of the ACE procedure for incontinence in adults and its impact upon quality of life.
Method All patients who underwent an ACE procedure between 1999 and 2009 were included. Clinical and demographic data and postoperative course were obtained from a review of medical records and databases. Each patient underwent a telephone interview. Quality of life was assessed using the GIQLI and SF36 scores, and faecal incontinence was evaluated using the Wexner score.
Results Seventy‐five patients (54 females; 72%) were included. An ileal neoappendicostomy was performed in 68 patients (90%). The mean hospital stay was 9 days (range 6–24 days). Early complications occurred in four patients and late surgical complications (after 3 months) were observed in 12 (16%) patients. At a median follow up of 48 months, 64 (91%) were still performing enemas, and treatment was judged to be successful in 55 (86%) of 64 patients. The Wexner score was 3.4 ± 2.4, showing a significant reduction when compared with the preoperative value (P < 0.0001). Quality of life scores were in the range of a control population.
Conclusion The ACE procedure is an effective long‐term strategy in the treatment of faecal incontinence, with low and acceptable morbidity, and should be preferred before definitive colostomy.
During summer in Brittany, France, sea farmed brown trout, Salmo trutta L., regularly experience a high mortality rate which is associated, at least in part, with cardiac disorders (aneurysms and ...infarcts). The present study is preliminary to a more extensive research programme, the objective of which is to determine to what extent the physiological performance of the cardiovascular system of brown trout is affected by the environmental conditions the fish experience in farm cages. We conducted a 2‐week in situ experiment during which the heart rate of eight sea water acclimatized individuals was telemetered using acoustic tags. During the experimental period, water temperature ranged from 16.0 to 17.6 °C. Water oxygen saturation was above 80% at all times and salinity was very high (35.5‰) but stable. Although they were unfed and not active, seven of out the eight tagged animals displayed near maximum heart beat frequencies, which ranged between 83 and 98 beats per minute (bpm). On the other hand, the eighth animal exhibited medium‐range heart rates (50–70 bpm). Using phase delay maps, we established that the maximum heart rate of brown trout at 17 °C was in the range of 96–100 bpm. This result suggests that in our experimental conditions, the heart rate of most of our inactive fish was between 85 and 100% of maximum myocardial performance. We hypothesize that the cardiac failures observed in brown trout during summer are most likely a result of strenuous workloads imposed on the cardiovascular system by a combination of elevated temperature, high salinity and possibly season‐related decreased hypo‐osmoregulatory abilities.
Phys. Rev. X 12, 021025 (2022) The material $\alpha$-RuCl$_3$ has been the subject of intense scrutiny as a
potential Kitaev quantum spin liquid, predicted to display Majorana fermions as
low energy ...excitations. In practice, $\alpha$-RuCl$_3$ undergoes a transition
to a state with antiferromagnetic order below a temperature $T_{\rm N}$
$\approx$ 7 K, but this order can be suppressed by applying an external
in-plane magnetic field of $H_\parallel$ = 7 T. Whether a quantum spin liquid
phase exists just above that field is still an open question, but the reported
observation of a quantized thermal Hall conductivity at $H_\parallel$ $>$ 7 T
by Kasahara and co-workers $\big$Kasahara ${\it et \ al}$., Nature ${\bf
559}$, 227 (2018)$\big$ has been interpreted as evidence of itinerant Majorana
fermions in the Kitaev quantum spin liquid state. In this study, we re-examine
the origin of the thermal Hall conductivity $\kappa_{\rm xy}$ in
$\alpha$-RuCl$_3$. Our measurements of $\kappa_{\rm xy}$($T$) on several
different crystals yield a temperature dependence very similar to that of the
phonon-dominated longitudinal thermal conductivity $\kappa_{\rm xx}$($T$), for
which the natural explanation is that $\kappa_{\rm xy}$ is also mostly carried
by phonons. Upon cooling, $\kappa_{\rm xx}$ peaks at $T \simeq$ 20 K, then
drops until $T_{\rm N}$, whereupon it suddenly increases again. The abrupt
increase below $T_{\rm N}$ is attributed to a sudden reduction in the
scattering of phonons by low-energy spin fluctuations as these become partially
gapped when the system orders. The fact that $\kappa_{\rm xy}$ also increases
suddenly below $T_{\rm N}$ is strong evidence that the thermal Hall effect in
$\alpha$-RuCl$_3$ is also carried predominantly by phonons. This implies that
any quantized signal from Majorana edge modes would have to come on top of a
sizable -- and sample-dependent -- phonon background.
The reliable assessment of the invasiveness of gliomas in vitro has proved elusive, because most invasion assays inadequately model in vivo invasion in its complexity. Recently, organotypical brain ...cultures were successfully used in short-term invasion studies on glioma cell lines. In this paper the authors report that the invasiveness of human glioma biopsy specimens directly implanted into rodent brain slices by using the intraslice implantation system (ISIS) can be quantified with precision. The model was first validated by the demonstration that, in long-term studies, established glioma cells survive in the ISIS and follow pathways of invasion similar to those in vivo.
Brain slices (400 microm thick) from newborn mice were maintained on millicell membranes for 15 days. Cells from two human and one rodent glioblastoma multiforme (GBM) cell lines injected into the ISIS were detected by immunohistochemistry or after transfection with green fluorescent protein-containing vectors. Preferential migration along blood vessels was identified using confocal and fluorescent microscopy. Freshly isolated (< or = 24 hours after removal) 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-prelabeled human glioma biopsy specimens were successfully implanted in 19 (83%) of 23 cases, including 12 GBMs and seven lower grade gliomas (LGGs). Morphometric quantification of distance and density of tumor cell invasion showed that the GBMs were two to four times more invasive than the LGGs. Heterogeneity of invasion was also observed among GBMs and LGGs. Directly implanted glioma fragments were more invasive than spheroids derived from the same biopsy specimen.
The ISIS combines a high success rate, technical simplicity, and detailed quantitative measurements and may, therefore, be used to study the invasiveness of biopsy specimens of gliomas of different grades.
La formation en grammaire des futurs enseignants de français est périodiquement discutée, l'enseignement grammatical demeurant un terrain de profondes tensions et contradictions. À l'heure de ...changements majeurs qui affectent les systèmes éducatifs universitaires et les publics scolaires, il importe de faire le point. Quels sont les finalités, approches, dispositifs et contenus de formation en grammaire dans les institutions académiques francophones ? Quelles doivent être les exigences de la formation, compte tenu des connaissances préalables des étudiants, des prescriptions et des besoins des élèves ? Cet ouvrage réunit des contributions de didacticiens belges, français, québécois et suisses. Formateurs aguerris, ces auteurs font le pari que plusieurs des problèmes de l’enseignement grammatical peuvent être résolus par la mise en œuvre d’une formation initiale dotant les enseignants d’outils qui leur permettent de maitriser eux-mêmes les phénomènes linguistiques complexes.
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