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Who has not experienced that sensation of losing the power of speech owing to an involuntary bout of laughter? An investigation of this phenomenon affords an insight into the neuronal processes that underlie laughter. In our functional magnetic resonance imaging study, participants were made to laugh by tickling in a first condition; in a second one they were requested to produce vocal utterances under the provocation of laughter by tickling. This investigation reveals increased neuronal activity in the sensorimotor cortex, the anterior cingulate gyrus, the insula, the nucleus accumbens, the hypothalamus and the periaqueductal grey for both conditions, thereby replicating the results of previous studies on ticklish laughter. However, further analysis indicates the activity in the emotion-associated regions to be lower when tickling is accompanied by voluntary vocalization. Here, a typical pattern of activation is identified, including the primary sensory cortex, a ventral area of the anterior insula and the ventral tegmental field, to which belongs to the nucleus ambiguus, namely, the common effector organ for voluntary and involuntary vocalizations. During the conflictual voluntary-vocalization versus laughter experience, the laughter-triggering network appears to rely heavily on a sensory and a deep interoceptive analysis, as well as on motor effectors in the brainstem. This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.

International audience; Objectives: To describe the epidemiology and prognostic impact of pneumonia in acute ischemic stroke patients requiring invasive mechanical ventilation. Methods: Retrospective analysis from a prospective multicenter cohort study of critically ill patients with acute ischemic stroke requiring invasive mechanical ventilation at admission. Impact of pneumonia was investigated using Cox regression for 1-year mortality, and competing risk survival models for ICU mortality censored at 30-days. Results: We included 195 patients. Stroke was supratentorial in 62% and 64% of patients had a Glasgow coma scale score \textless8 on admission. Mortality at day-30 and 1 year were 56%, and 70%, respectively. Post-stroke pneumonia was identified in 78 (40%) patients, of which 46/78 (59%) episodes were present at ICU admission. Post-stroke pneumonia was associated with an increase in 1-year mortality (adjusted HR 1.49, 95% CI [1.01-2.20]). Post-stroke pneumonia was not associated with ICU mortality but was associated with a 1.6-fold increase in ICU length of stay (CSHR 0.62 [0.39-0.99], p = 0.06). Conclusions: In ischemic stroke patients requiring invasive ventilation, pneumonia occurred in 40% of cases and was associated with a 49% increase in 1-year mortality. Post-stroke pneumonia did not impact day-30 mortality but increased ICU length of stay. (C) 2019 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Variability of blood pressure responses to inhibition of the renin-angiotensin system is influenced by factors inherent in the patient, such as renin status, and by drug-specific factors, such as pharmacokinetics. The pharmacokinetic-pharmacodynamic interactions of two doses of candesartan cilexetil, which is an ester prodrug of the insurmountable angiotensin II type 1 (AT 1 ) receptor blocker candesartan, were compared with those of the standard dose of losartan in normotensive volunteers whose renin status was controlled by mild sodium depletion. In a double-blind, placebo-controlled crossover study, the effects of single oral doses of candesartan cilexetil, 8 mg and 16 mg, and losartan, 50 mg, were compared for 24 h in 16 healthy individuals pretreated with a single 40-mg dose of furosemide. Mean blood pressure was recorded by repeated measurements using the oscillometric method. In addition, measurements were made of plasma active renin, angiotensin I and angiotensin II, and plasma levels of candesartan and EXP-3174, the active metabolites of candesartan cilexetil and losartan, respectively, were determined by high-performance liquid chromatography and correlated to pharmacodynamic changes. The large interindividual variability of EXP-3174 levels in subjects who received losartan revealed a significant correlation between active renin and peak drug levels ( r = 0.77, n = 16, p < 0.01). Such a correlation was not found within either group of individuals who received candesartan cilexetil, because of lower interindividual pharmacokinetic variability. A dose-response relationship was found between plasma renin and candesartan when both doses of candesartan cilexetil were analysed. The pharmacodynamic effects of a single oral dose of candesartan cilexetil, 16 mg, were superior to those of candesartan cilexetil, 8 mg, and losartan, 50 mg (see Table). This conclusion has been confirmed by the results of a parallel-group, dose-determination study performed in hypertensive patients. The less variable pharmacokinetic-pharmacodynamic interaction for candesartan cilexetil than for losartan could account for the smooth 24-h reduction in blood-pressure found in patients treated with candesartan cilexetil. These results suggest not only that AT 1 -receptor antagonists can be differentiated, but that they will not be equally useful in clinical practice where, in contrast to clinical research, clear evidence is more difficult to obtain because of variability in renin status.

For the past 40 years, primary hyperparathyroidism has been recognized as a common endocrine disease which is, most often, “non-symptomatic”, without the occurrence of nephrolithiasis or osteitis fibrosa cystica. Our knowledge in the pathophysiology has increased largely and diagnosis of primary hyperparathyroidism is usually easy. The only radical treatment is surgery and the surgical indications have been codified by several consensus conferences. For patients who do not undergo surgery, prolonged medical monitoring is needed.

The Gaza Strip suffers severe constraints in water supply due to its location, confinement, high population density and semi-arid coastal climate. To improve water and agricultural resources, a study was undertaken to show the requirements in planning and management for wastewater treatment, irrigation conveyance and aquifer recharge to meet high technical standards and sustainable economic benefits. Particular attention is paid to economic, financial and socioeconomic analysis. This paper discusses the impact that wastewater reuse will have on the water resources as part of the overall water balance in the Gaza Strip.

A theoretical model, which relates the binding energy of a positively charged exciton in a quantum dot with the confinement energy is presented. It is shown that the binding energy, defined as the energy difference between the corresponding charged and neutral complexes confined on the same excitonic shell strongly depends on the shell index. Moreover, it is shown that the ratio of the binding energy for positively charged excitons from the $p$- and $s$-shells of a dot depends mainly on the nearly perfect confinement in the dot, which is due to the "hidden symmetry" of the multi-electron-hole system. We applied the theory to the excitons confined to a single GaAlAs/AlAs quantum dots. The relevant binding energy was determined using the micro-photoluminescence and micro-photoluminescence excitation magneto-spectroscopy. We show that within our theory, the confinement energy determined using the ratio of the binding energy corresponds well to the actual confinement energy of the investigated dot., Comment: 6 pages, 5 figures

When light interacts with metal surfaces, it excites electrons, which can form propagating excitation waves called surface plasmon polaritons. These collective electronic excitations can produce strong electric fields localized to subwavelength distance scales 1 , which makes surface plasmon polaritons interesting for several applications. Many of these potential uses, and in particular those related to quantum networks 2 , r equire a deep understanding of the fundamental quantum properties of surface plasmon polaritons. Remarkably, these collective electron states preserve many key quantum mechanical properties of the photons used to excite them, including entanglement 3,4 and sub-Poissonian statistics 5 . Here, we show that a single-photon source coupled to a silver nanowire excites single surface plasmon polaritons that exhibit both wave and particle properties, similar to those of single photons. Furthermore, the detailed analysis of the spectral interference pattern provides a new method to characterize the dimensions of metallic waveguides with nanometre accuracy.

We report on single-object spectroscopic studies of a characteristic set of three resonances which appear in GaAlAs/AlAs quantum dot structures. The experiments included the photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy, photon-correlation measurements, analysis of the linear polarization of the emission spectra as well as the PL and PLE spectroscopy performed as a function of magnetic field. The investigated resonances are assigned to three different states of a positively charged exciton: a singlet ground state, a conventional triplet state (involving an electron from the ground state electronic $s$-shell), and additionally, a highly excited triplet state (involving the electron from the excited electronic $p$-shell). Advantageously (due to partially suppressed relaxation efficiency), the emission due to the highly excited triplet can seen in the spectra which allows us to scrupulously determine its properties and compare them to those of the conventional triplet state. Whereas both triplet states show similar patterns of the fine structure and Zeeman splitting, the splitting amplitudes are found to be significantly different for these two states. The presented results emphasize the role of the symmetry of the electronic state on the properties of the triplet states of the two holes + electron excitonic complex., Comment: 6 pages, 5 figures

We study single dibenzoterrylene molecules in an anthracene single crystal at 1.4 K in two insertion sites at 785.1 and 794.3 nm. The single-molecule zero-phonon lines are narrow (about 30 MHz), intense (the detected fluorescence rates at saturation reach 100,000 counts s(-1)), and very photostable. The intersystem-crossing yield is extremely low (10(-7) or lower). All of these features are hallmarks of an excellent system for high-resolution spectroscopy and nanoscale probing at cryogenic temperatures.

International audience; The Aharonov-Bohm effect in ring structures in the presence of electronic correlation and disorder is an open issue. We report novel oscillations of a strongly correlated exciton pair, similar to a Wigner molecule, in a single nanoquantum ring, where the emission energy changes abruptly at the transition magnetic field with a fractional oscillation period compared to that of the exciton, a so-called fractional optical Aharonov-Bohm oscillation. We have also observed modulated optical Aharonov-Bohm oscillations of an electron–hole pair and an anticrossing of the photoluminescence spectrum at the transition magnetic field, which are associated with disorder effects such as localization, built-in electric field, and impurities.

The absence of an energy gap separating valence and conduction bands makes the low-energy electronic properties of graphene and its multi-layers sensitive to electron-electron interactions. In bilayers, for instance, interactions are predicted to open a gap at charge neutrality, turning the system into an insulator, as observed experimentally. In mono and (Bernal-stacked) trilayers, interactions, although still important, do not have an equally drastic effect, and these systems remain conducting at low temperature. It may be expected that interaction effects become weaker for thicker multilayers, whose behavior should eventually converge to that of graphite. Here we show that this expectation does not correspond to reality by investigating the case of Bernal-stacked tetralayer graphene (4LG). We reveal the occurrence of a robust insulating state in a narrow range of carrier densities around charge neutrality, incompatible with the behavior expected from the single-particle band structure. The phenomenology resembles that observed in bilayers, but the stronger conductance suppression makes the insulating state in 4LG visible at higher temperature. To account for our findings, we suggest a natural generalization of the interaction-driven, symmetry-broken states proposed for bilayers. This generalization also explains the systematic even-odd effect of interactions in Bernal-stacked layers of different thickness that is emerging from experiments, and has implications for the multilayer-to-graphite crossover., 15 pages, 5 figures, This is the original submitted version of the manuscript whose final accepted version, following the review/editorial process, will appear in Nature Communications

The miniaturization of electronic devices and structures brings along the quest for instruments that operate on mesoscopic and nanometric scales. In these structures, nano-instruments could elucidate the rich variety of physical processes, an understanding of which will be necessary to develop and to predict the function of new nanoscale devices. For this purpose, we propose to use single molecules as nanoprobes and to address the probes individually by means of optical single molecule microscopy and spectroscopy. This would allow us to study the conduction in molecular crystals. Here, we compare different material systems and show that dibenzoterrylene in an anthracene crystal is a promising candidate system.

Optical anisotropy of charged excitons and biexcitons related to the single-particle sand p-shell emission in GaAlAs/AlAs quantum dots is investigated. The polarization-dependence and time-resolved micro-photoluminescence measurements were performed. Cross-correlation measurements were used to identify the ladder of excitonic states and allowed us to show two cascade pathways, including the spin singlet and triplet states of charged excitons and biexcitons. The ne structure of the studied states is described and analysed in terms of electron electron, hole hole, and electron hole exchange interactions. DOI: 10.12693/APhysPolA.124.785 PACS: 78.67.Hc, 71.35.−y, 78.55.Cr, 71.70.Gm

We detail the influence of a magnetic field on exciton-polaritons inside a semiconductor microcavity. Magnetic field can be used as a tuning parameter for exciton and photon resonances. We discuss the change of the exciton energy, the oscillator strength, and redistribution of the polariton density along the dispersion curves due to the magnetically induced detuning. We have observed that field-induced shrinkage of the exciton wave function has a direct influence not only on the exciton oscillator strength, which is observed to increase with the magnetic field, but also on the polariton linewidth. We discuss the effect of the Zeeman splitting on polaritons the magnitude of which changes with the exciton Hopfield coefficient and can be modeled by independent coupling of the two spin components of excitons with cavity photons.

The quantum confinement in a typical quantum dot (QD) is determined primarily by the nanosystem's dimensions and average composition. We demonstrate, however, that excitonic properties of natural QDs formed in the InAs/GaAs wetting layer are governed predominantly by effects of random fluctuations of the lattice composition. It is shown that the biexciton binding energy is a very sensitive function of the lattice randomness with a nearly flat dependence on the exciton energy. The large variation in different random realizations of a QD structure is shown to lead in some cases to the reversal of the order of excitonic lines. Results of theoretical calculations correspond to statistical properties of neutral excitons and biexcitons as well as trions confined to single natural QDs studied in our microspectroscopic measurements. We observe substantial variation of the biexciton and trion binding energies as well as a correlation of the trion and the biexciton energies. The transition from the negative to the positive binding energy of the trion is also observed, which strongly supports the attribution of the observed trion to the positively charged exciton.

We report the properties of emission lines associated with the cascaded recombination of a quadexciton in single GaAlAs/AlAs quantum dots, studied by means of polarization-resolved photoluminescence and single-photon correlation experiments. It is found that photons which are emitted in a double-step 4X-3X process preserve their linear polarization, similarly to the case of conserved polarization of correlated photons in the 2X-X cascade. In contrast, an emission of either co-linear or cross-linear pairs of photons is observed for the 3X-2X cascade. Each emission line associated with the quadexciton cascade shows doublet structure in the polarization-resolved photoluminescence experiment. The maximum splitting is seen when the polarization axis is chosen along and perpendicular to the [110] crystallographic direction. This effect is ascribed to the fine structure splitting of the exciton and triexciton states in the presence of an anisotropic confining potential of ae dot. We also show that the splitting in the triexciton state surpasses that in the exciton state by a factor up to eight and their ratio scales with the energy distance between the 3X and X emission lines, thus, very likely, with a lateral size and/or a composition of the dot., Comment: submitted to Physical Review B

Magnetic Field E ect on the Excitation Spectrum of a Neutral Exciton in a Single Quantum Dot M.R. Molas, A.A.L. Nicolet, B. Pi¦tka, A. Babi«ski and M. Potemski Faculty of Physics, University of Warsaw, L. Pasteura 5, 02-093 Warszawa, Poland Laboratoire National des Champs Magnetiques Intenses, CNRS-UJF-UPS-INSA, 25, av. des Martyrs, 38042 Grenoble, France Excitation-energy-dependent magnetospectroscopic measurements of a single GaAlAs/AlAs quantum dot were performed. A signi cant e ect of the excitation energy on the photoluminescence spectra is reported. The photoluminescence excitation spectroscopy has been used to investigate the excitation spectrum of a single electron hole pair a neutral exciton in magnetic eld up to 14 T. The observed resonances exhibit diamagnetic shift characteristic of an s-shell related emission. In our opinion, the creation of excited complexes involving an excited hole and a ground electron is responsible for the process.

The use and recirculation of powdered activated carbon (PAC) as an advanced treatment for colour removal in municipal wastewater treatment plants is presented. Studied wastewaters consist of domestic effluents with a high portion of dyehouse residual waters. The particularity of the treatment is that PAC is not disposed of before being recirculated several times. Therefore, it enables the use of a great part of the total adsorption capacity of the PAC. A positive side effect is that halogenated and refractory organic compounds, which are not degraded by micro-organisms in a conventional municipal wastewater treatment plant, are removed too. This paper describes results which were obtained in batch experiments and in a pilot plant during two years of observation, and concludes with advantages and drawbacks of this technology.

We report a comprehensive study of the tuning with electric fields of the resonant magneto-exciton optical phonon coupling in gated graphene. For magnetic fields around $B \sim 25$ T which correspond to the range of the fundamental magneto-phonon resonance, the electron-phonon coupling can be switched on and off by tuning the position of the Fermi level in order to Pauli block the two fundamental inter Landau level excitations. The effects of such a profound change in the electronic excitation spectrum are traced through investigations of the optical phonon response in polarization resolved magneto-Raman scattering experiments. We report on the observation of a splitting of the phonon feature with satellite peaks developing, at particular values of the Landau level filling factor, on the low or on the high energy side of the phonon, depending on the relative energy of the discrete electronic excitation and of the optical phonon. Shifts of the phonon energy as large as $\pm60$ cm$^{-1}$ are observed close to the resonance. The intraband electronic excitation, the cyclotron resonance, is shown to play a relevant role in the observed spectral evolution of the phonon response., Comment: 5 Figures

We report on a magneto-Raman scattering study of graphene flakes located on the surface of a bulk graphite substrate. By spatially mapping the Raman scattering response of the surface of bulk graphite with an applied magnetic field, we pinpoint specific locations which show the electronic excitation spectrum of graphene. We present the characteristic Raman scattering signatures of these specific locations. We show that such flakes can be superimposed with another flake and still exhibit a graphene-like excitation spectrum. Two different excitation laser energies (514.5 and 720 nm) are used to investigate the excitation wavelength dependence of the electronic Raman scattering signal., Comment: 6 pages, 5 figures

We observe excited exciton and biexciton states of localised excitons in an anisotropic quantum ring, where large polarisation asymmetry supports the presence of a crescent-like localised structure. We also find that saturation of the localised ground state exciton with increasing excitation can be attributed to relatively fast dissociation of biexcitons (? 430 ps) compared to slow relaxation from the excited state to the ground state (? 1000 ps). As no significant excitonic Aharonov-Bohm oscillations occur up to 14 T, we conclude that phase coherence around the rim is inhibited as a consequence of height anisotropy in the quantum ring., Comment: 4 pages, 4 figures

For the past 40 years, primary hyperparathyroidism has been recognized as a common endocrine disease which is, most often, "non-symptomatic", without the occurrence of nephrolithiasis or osteitis fibrosa cystica. Our knowledge in the pathophysiology has increased largely and diagnosis of primary hyperparathyroidism is usually easy. The only radical treatment is surgery and the surgical indications have been codified by several consensus conferences. For patients who do not undergo surgery, prolonged medical monitoring is needed.

The micro-Raman scattering response of a graphene-like location on the surface of bulk natural graphite is investigated both at $T=\unit{4.2}{K}$ and at room temperature in magnetic fields up to 29 T. Two different polarization configurations, co-circular and crossed-circular, are employed in order to determine the Raman scattering selection rules. Several distinct series of electronic excitations are observed and we discuss their characteristic shapes and amplitudes. In particular, we report a clear splitting of the signals associated with the inter-Landau level excitations $-n\rightarrow+n$. Furthermore, we observe the pronounced interaction of the zone-center E$_{\text{2g}}$-phonon with three different sets of electronic excitations. Possible origins for these graphene-like inclusions on the surface of bulk graphite are discussed., 10 pages, 11 figures

We use polarized magneto-Raman scattering to study purely electronic excitations and the electron-phonon coupling in bulk graphite. At a temperature of 4.2 K and in magnetic fields up to 28 T we observe $K$-point electronic excitations involving Landau bands with $\Delta |n|=0$ and with $\Delta |n|=\pm2$ that can be selected by controlling the angular momentum of the excitation laser and of the scattered light. The magneto-phonon effect involving the $E_{2g}$ optical phonon and $K$-point inter Landau bands electronic excitations with $\Delta |n|=\pm1$ is revealed and analyzed within a model taking into account the full $k_z$ dispersion. These polarization resolved results are explained in the frame of the Slonczewski-Weiss-McClure (SWM) model which directly allows to quantify the electron-hole asymmetry., Comment: 13 pages, 10 figures

Photoluminescence quenching of single dibenzoterrylene (DBT) dye molecules in a polymeric organic light-emitting diode was utilized to analyze the current dynamics at nanometer resolution. The quenching mechanism of single DBT molecules results from an increase in the triplet-state population induced by charge carrier recombination on individual guest molecules. As a consequence of the long triplet-state relaxation time, its population results in a reduced photoluminescence of the dispersed fluorescent dyes. From the decrease in photoluminescence together with photon correlation measurements, we could quantify the local current density and its time-dependent evolution in the vicinity of the single-molecule probe. This optical technique establishes a non-invasive approach to map the time-resolved current density in organic light-emitting diodes on the nanometer scale.

Magneto-Raman scattering experiments from the surface of graphite reveal novel features associated to purely electronic excitations which are observed in addition to phonon-mediated resonances. Graphene-like and graphite domains are identified through experiments with $\sim 1\mu m$ spatial resolution performed in magnetic fields up to 32T. Polarization resolved measurements emphasize the characteristic selection rules for electronic transitions in graphene. Graphene on graphite displays the unexpected hybridization between optical phonon and symmetric across the Dirac point inter Landau level transitions. The results open new experimental possibilities - to use light scattering methods in studies of graphene under quantum Hall effect conditions., Comment: 4 pages, 5 figures; revised manuscript with additional data

International audience; Cucurbita moschata ‘Menina’ originating from Portugal is known to carry a single dominant gene, Zym, for zucchini yellow mosaic virus (ZYMV) resistance. Resistance to watermelon mosaic virus type 2 (WMV2) was found in the same cultivar. In resistant plants, WMV2 migration from inoculated leaves or cotyledons seems to be limited and blocked. Resistance to WMV2 is conferred by one dominant gene and is effective against eight strains from different geographic origins. Results of linkage studies, based on co-inoculation of plants with WMV2 and ZYMV, indicate that resistance to these two viruses is conferred by the same gene, probably Zym, or perhaps by two closely linked genes.

We monitored the spectral shifts of single molecule lines under an applied ac voltage in a molecular crystal at a low temperature. When varying the voltage modulation frequency, we found pronounced resonances in the oscillating shift of the optical lines. The resonance frequencies are surprisingly low and are found anywhere in the explored region, from some tens of kHz to a few MHz. Their width and amplitude depend very steeply on temperature, with quality factors as high as a few hundred at 1.4K. Probing the resonant modes with single molecules at different locations, we find a clear spatial correlation of the modes within microcrystalline domains, extending over 10-100µm. For large amplitudes, the oscillations become anharmonic and display a range of nonlinear effects: decrease of the frequency with amplitude, hysteretic behavior depending on the scan direction and shift of the frequency whenan external strain is applied to the sample. Put together, our observations point to low-frequency acoustic modes localized at or around crystal defects. This work is closely related to earlier observations of similar resonances in Shpol'skii matrices deposited on a semiconductor. We speculate on the relation of these acoustic modes to the low-energy modes (quasi-localized modes and Boson-peak excitations) already known in disordered solids.

Our low-temperature magneto-Raman scattering measurements performed on graphene-like locations on the surface of bulk graphite, carries the energyite reveal a new series of magneto-phonon resonances involving both K point and Γ point phonons. These are resonances between a purely electronic excitation, an electronic excitation accompanied by one phonon, and a two-phonon excitation. In particular, we observe the resonant splitting of three crossing excitation branches. We give a detailed theoretical analysis of these multi-excitation resonances. Our results highlight the role of combined excitations and the importance of multi-phonon processes (from both K and Γ points) for the relaxation of hot carriers in graphene.

International audience; We present a spectroscopic study of the properties of the two principal insertion sites (at 785.1 and 794.3 nm) of single dibenzoterrylene molecules in anthracene single crystals at cryogenic temperatures. We measured the temperature dependence of the line width, the orientation of the transition dipole moments, and the Stark effect. We performed molecular dynamics simulations, which show that one dibenzoterrylene molecule preferably repla ces three anthracene molecules. From simulated annealing, we derive the molecular conformations in the most stable insertion sites and the orientations of the transition dipole moments. The good agreement between the spectroscopic results and the simulations allows us to propose unambiguous structures for the two principal spectroscopic sites. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

We present a spectroscopic study of terrylene in anthracene crystals at the ensemble and single-molecule levels. In this matrix, single-molecule fluorescence is reduced by three orders of magnitude. Correlation measurements allow us to identify a new relaxation channel, matrix-enhanced intersystem crossing. This process starts with a singlet-to-triplet energy transfer from guest to host, after which the triplet exciton is transferred back to the guest. The intermolecular intersystem crossing is expected whenever the lowest triplet state of the host is located between the lowest singlet S(1) and lowest triplet T(1) excited states of the guest. It must be considered when searching for new host-guest systems for single-molecule spectroscopy.

The hemoregulatory peptide Acetyl-Ser-Asp-Lys-Pro (AcSDKP) has been reported to accumulate in plasma and urine after the oral administration of angiotensin-converting enzyme (ACE) inhibitors in humans. It is unknown whether such an accumulation also occurs in tissues. We administered captopril (3, 10, or 30 mg/kg) orally for 2 weeks to Wistar rats. In a second experiment, captopril (10 mg/kg) was administered for 9 days and was followed by a 1-h i.v. infusion of either AcSDKP (0.1 or 2 mg/kg) or saline on day 9. Captopril alone dose-dependently increased plasma AcSDKP by a factor of 3 to 5 and urine AcSDKP by a factor of 3. It slightly increased renal and pulmonary AcSDKP concentrations but did not affect AcSDKP concentrations in bone marrow and spleen. The combination of AcSDKP (2 mg/kg) and captopril gave very high AcSDKP concentrations in plasma and urine and increases in AcSDKP concentration by factors of 27 in kidney, 5.5 in lung, and 6.9 in the extracellular fraction of bone marrow. In contrast, no change was observed in the AcSDKP concentration in spleen and in the intracellular fraction of bone marrow. In conclusion, during chronic ACE inhibition in rats, AcSDKP levels slightly increased in organs with high ACE contents. No such increase occurred in hematopoietic organs. AcSDKP had to be combined with captopril to significantly increase its concentration in tissues other than the spleen. The possibility of pharmacologically increasing AcSDKP levels in the extracellular fraction of bone marrow may be of value for protecting hematopoietic cells from the toxicity of cancer chemotherapy.

Optical emission spectrum of a resonantly (λ = 632.8 nm) excited molybdenum disulfide (MoS2) is studied at liquid helium temperature. More than 20 peaks in the energy range spanning up to 1400 cm−1 from the laser line, which are related to multiphonon resonant Raman scattering processes, are observed. The attribution of the observed lines involving basic lattice vibrational modes of MoS2 and both the longitudinal (LA(M)) and the transverse (TA(M) and/or ZA(M)) acoustic phonons from the vicinity of the high-symmetry M point of the MoS2 Brillouin zone is proposed.

We studied charge transport in a field-effect transistor based on an anthracene crystal by single-molecule spectroscopy at cryogenic temperatures. When applying a control voltage to the gate, source and drain electrodes, we observe spectral drifts of the probe molecules' lines, which follow strongly non-exponential (stretched) kinetics, from seconds to tens of minutes. Applying a gate voltage alone, we find a dependence of the spectral shift as the logarithm of time. When an additional source-drain voltage is applied, the spectral shift follows a power law of time, similar to the elementary step of conduction in amorphous solids, postulated in the continuous-time random walk theory of Scher and Montroll.

Ziel des Fachgesprachs ist es, mit Menschen aus Unternehmen, Wissenschaft und Institutionen der Entwicklungszusammenarbeit folgende Themen zu vertiefen: Globale Dezentralisierung von Unternehmen: Datennetze und das virtuelle Unternehmen — Erfahrungen aus Entwicklungslandern Neue Formen in Forschung und Ausbildung: Eroffnet sich durch globale Vernetzung eine intensivierte wissenschaftliche Kooperation Nord-Sud/Sud-Sud? Wirtschaftliche Entwicklungschancen durch Software-Produktion und Software-Export fur Staaten der „Dritten Welt“? (Erfahrungen z.B. aus Brasilien, Chile, Indien, Malaysia, Philippinen ... ) Welche Konsequenzen sind fur Industrielander absehbar, z.B. Abbau von Informatik-Arbeitsplatzen? Kann die Informatisierung einen Beitrag fur nachhaltige Entwicklung (sustainable development) in Entwicklunglandern leisten? Demokratie und Informationsaustausch utiber Landergrenzen hinweg: Sind internationale und regionale Kooperationsformen leichter zu fordern?

The author argues that it is indispensable, in order to avoid serious problems, to take into account from the beginning of the design of any technological complex system (e.g., a nuclear power plant) cultural differences which could exist between the country issuing the technology (sending community) and the country in charge of operating it during several decades (receiving community). Experience shows that any technology transfer must be considered as a clash of two more or less remote and compatible cultures. Failure to take this phenomenon into account may jeopardize the future of the project. >

We present the characterization of an anthracene single-crystal organic field-effect transistor in the temperature-range of 4.2 to 290 K. We recorded the source-drain current as a function of the applied voltages (source-drain and gate). The measured curves exhibit a superlinear dependence when plotted on a log-log scale with an exponent larger than two, which is typical of a trap-filling regime. At low temperatures, the source-drain current becomes temperature independent and shows a plateau. We estimate a lower bound of the mobility at different temperatures.

Single molecule spectroscopy requires molecules with low triplet yields and/or short triplet lifetimes. The intersystem crossing (ISC) rate may be dramatically enhanced by the host matrix. Comparing the fluorescence intensity of single terrylene molecules in para-terphenyl, naphthalene, and anthracene crystals, we found a reduction of the saturation intensity by three orders of magnitude in the latter case. The fluorescence autocorrelation function indicates that the bottleneck state is the terrylene triplet. We propose a ping-pong mechanism between host and guest. This intermolecular ISC mechanism, which can open whenever the host triplet lies lower than the guest singlet, was overlooked in previous single molecule investigations.

Ce texte a ete etabli par les auteurs a partir d'extraits de leur livre « La Fiabilite humaine dans l'entreprise » (Edition Masson, decembre 1984).