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The transformation of m-xylene was investigated at 350 °C over a MWW zeolite sample. The distributions of the desorbed products and of the nondesorbed products (“coke”) were established for a large range of contact times, hence of conversions (from 4.8 to 43.7%), and for different times on stream (TOS). A rapid deactivation can be observed during the first 10 min of reaction, followed by a quasi plateau in activity. On the fresh sample (TOS=2 min), m-xylene was transformed into isomers and disproportionation products (toluene and trimethylbenzenes or TMB); TMB underwent various secondary reactions leading to ethyltoluenes, C2–C4 alkanes and alkenes, toluene, and coke. Deactivation causes a small decrease in isomerization and suppresses disproportionation and secondary TMB transformations. These latter reactions were demonstrated to occur only in the supercages. On the other hand, approximately 30% of isomerization took place in the supercages and 70%, without any deactivation, in the sinusoidal channels and in the external pockets. [Copyright &y& Elsevier]

An infant perceptual experiment investigated the role of prosody. All-nonsense-word sentences (e.g., Guin felli crale vur ti gosine), each in structure 1 ([[Determiner + Adjective + Noun] [Verb + Determiner + Noun]]) and structure 2 ([[Determiner + Noun] [Verb + Preposition + Determiner + Noun]]), were recorded (by mimicking real-word French sentences) with disambiguating prosodic groupings matching the two major constituents. French-learning 20- and 24-month-olds were familiarized with either structure 1 or structure 2. All infants were tested with noun-use trials (e.g., Le crale "the crale-Noun") versus verb-use trials (Tu crales "You crale-Verb"). Structure-2-familiarized infants, but not structure-1-familiarized infants, discriminated the test trials, demonstrating that prosody alone guides verb categorization. Noun categorization requires determiners, as shown in earlier work [S. Massicotte-Laforge and R. Shi, J. Acoust. Soc. Am. 138(4), EL441-EL446 (2015)].

This study tested the hypothesis that phrasal prosody assists early syntactic acquisition. Stimulus-sentences consisting of French determiners and pseudo-lexical-words were ambiguous between two syntactic structures, e.g., [[TonDet felliAdj craleN]NP [vurV laDet gosineN]VP] versus [[TonDet felliN]NP [craleV vurPrep laDet gosineN]VP], which had distinct prosodic cues. French-learning 20-month-olds were familiarized with the sentences either in the prosody of one structure, or the other structure. All infants were tested with Det + N (e.g., LeDet craleN) versus Pron + V (e.g., TuPron cralesV) trials containing non-familiarized functors. Infants perceived the test-stimuli according to the familiarized structure. They used prosody to categorize words and interpret adjacent and non-adjacent syntactic dependencies.

Stress myocardial perfusion scintigraphy imaging (SMPSI) has important applications for evaluating coronary disease and ventricular function. Studies consistently focus on the left ventricle (LV), with no normal right ventricle (RV) data available. This study sought to evaluate the feasibility of RV perfusion with technetium (Tc-99m) sestamibi using a low radiotracer dose for children free of coronary artery (CA) anomalies and to determine its normal pattern. Patients with a history of Kawasaki disease who showed no coronary complications on selective angiography or no LV perfusion defects on SMPSI were studied at rest and during an exercise challenge. The RV uptake counts were compared with those for different segments of the LV, and multiple ratios of the uptakes between RV and LV segments were calculated. The study subjects were 23 children (age, 11.1 ± 3.3 years) imaged with 0.12 ± 0.03 mCi/kg at rest and 0.31 ± 0.06 mCi/kg during stress. The RV to LV uptake proportion was approximately 6%. Exercise-related uptake increased threefold in both the RV and the LV. The findings showed RV myocardial scintigraphy to be feasible with reproducible ratios. Potential clinical applications include acquired and congenital CA anomalies such as Kawasaki disease, right CA ostium stenosis after a switch operation, and anomalous origin of the right CA.

Costimulation of purified CD8(+) T lymphocytes induces de novo expression of CD4, suggesting a previously unrecognized function for this molecule in the immune response. Here, we report that the CD4 molecule plays a direct role in CD8(+) T cell function by modulating expression of IFN-gamma and Fas ligand, two important CD8(+) T cell effector molecules. CD4 expression also allows infection of CD8 cells by HIV, which results in down-regulation of the CD4 molecule and impairs the induction of IFN-gamma, Fas ligand, and the cytotoxic responses of activated CD8(+) T cells. Thus, the CD4 molecule plays a direct role in CD8 T cell function, and infection of these cells by HIV provides an additional reservoir for the virus and also may contribute to the immunodeficiency seen in HIV disease.

It was previously shown that costimulation of CD8(+) lymphocytes results in de novo expression of CD4. This study expanded on this observation to investigate the function of CD4 on CD8 cells. The ability of costimulated CD8 cells to respond to interleukin 16 (IL-16), a ligand that binds CD4 and induces cellular chemotaxis, was examined. IL-16-mediated ligation of CD4 expressed on CD8 T cells was found to induce an intracellular signal that directs migration of these cells in vitro. Thus, expression of CD4 on a CD8 lymphocyte has functional importance and may serve to control distribution of newly activated CD8 T cells in vivo.