Synchronous Exchange Research Articles

A dielectric study of the structure of propylene glycol

The dielectric spectra of propylene glycol over the frequency and temperature ranges 10 mHz–75 GHz and 175–423 K, respectively, were analyzed using the Dissado-Hill cluster model. A correlation between relaxation processes of breaking and formation of intermolecular H-bonds in clusters was obtained. A correlation of fluctuation processes of synchronous exchange of molecules between neighboring clusters corresponded to the redistribution of H-bonds between them. The Dissado-Hill theory was used to determine the integral relaxation times, n DH and m DH parameters and calculate the mean dipole moments of propylene glycol clusters and the energy characteristics of processes of their rearrangement. The mean dipole moments of clusters (23617–18.65 D) were compared with those of molecules in the liquid phase (3.67–3.03 D). The apparent activation enthalpy of processes of cluster rearrangements decreased from 141.8 to 25.2 kJ/mol, the activation energy decreased from 46.03 to 18.47 kJ/mol, and the energy of orientation dipole-dipole interactions, from 3.78 to 3.45 kJ/mol as the temperature increased.

Study on the treatment of severe neonatal hyperbilirubinemia by peripheral arteriovenous synchronous exchange transfusion

Objective To evaluate the efficacy, safety, and then understand the indication, clini-cal application of the peripheral arteriovenous synchronous exchange transfusion therapy on the infants with severe neonatal hyperbilirubinemia. Methods peripheral arteriovenous synchronous exchange transfusion was performed on 96 newly-born infants with hyperbilirnbinaemia. The changes of their blood routine, serum bilirubin, electrolyte, coagulation functions and blood glucose before and after the exchange transfusion were analyzed and the neurological symptoms, blood routine and serum bilirubin were continuously observed after treatment. Results The average decrease in serum total bilirubin concentration was 48.6%, mainly in indirect bilirubin, after exchange transfusion. Levels of leukocyte, template and serum potassium all had showed distinctive downtrend with P 0.05 through the treatment. The analysis of coagulation functions showed that both fibrinogen and active partial thromboplastin time decreased signifi-cantly with P 0.05 compared with itself before the exchange transfusion. Respiration/circulation suppression or necrotizing enterocolitis only oc-curred in individual cases. Conclusions Peripheral arteriovenous synchronous exchange transfusion has the advantages of good efficacy, safety find simple operation, but it is necessary to pay close attention on patients' life sign during and after the treatment. Key words: Exchange transfusion; Neonatal hyperbilirubinemia; Treatment

Passivity of Interconnected Asynchronous Discrete-Time Systems

This paper presents a constructive algorithm to design local controllers for feedback systems that are interconnected via time-varying and asynchronous sampling. These systems result in many application fields such as remotely-operated systems, interconnected vehicle control loops, and more generally in component-based control design where synchronous exchange of information is not feasible. The design is based on the (MASP) MAximum Sampling time preserving Passivity, and uses discrete-time passivity considerations. The paper first explores several ways to compute the MASP for linear systems, and then proposes a numerical algorithm to compute local feedback loops providing a MASP compatible with the maximum sampling-time upperbound of each sub-system. This results in a exponentially stable interconnection. The paper also presents a simulation example of this design.

Mother-infant synchrony and the development of moral orientation in childhood and adolescence: Direct and indirect mechanisms of developmental continuity.

Links between the temporal parameters of mother-infant synchrony and moral orientation in adolescence were examined in 31 children monitored from 3 months to 13 years. At 3 and 9 months, mother's and infant's affective states during face-to-face play were microcoded and synchrony was assessed with time-series analysis. Verbal IQ, behavior problems, child self-regulated compliance, and maternal warm control discipline were examined at 2, 4, and 6 years. Moral cognition and dialogical empathy were evaluated at 6 and 13 years. Three mechanisms of continuity were proposed: continuity in small steps, continuity through a mediating variable, and direct continuity. Mother-infant synchrony across the 1st year, indexed by the lagged associations between maternal and infant affective involvement, predicted verbal IQ and behavior adaptation, which in turn predicted moral cognition. Child self-regulated compliance across the toddler and preschool years mediated the relations between the lead-lag structure of early interactions and the adolescent's dialogical skills. Direct associations were found between mother-infant synchrony and the capacity for empathy in adolescence. Participating in a synchronous exchange may sensitize infants to the emotional resonance and empathy underlying human relationships across the life span.

Study of the rearrangement of cyclononatetraenyl(dipropyl)borane to 7,8-dipropyl-7-borabicyclo[4.2.2]deca-2,4,9-triene by NMR spectroscopy

Using NMR spectroscopy it was found that at ambient temperature 9-cyclononatetraenyl(dipropyl)borane (1) rapidly rearranges to give 7,8-dipropyl-7-borabicyclo[4.2.2]deca-2,4,9-triene (2),cis-endo-9-dipropylborylbicyclo[6.1.0]nona-2,4,6-triene (3a), and two isomeric boranes with dihydroindene skeletons (4a,b) (the ratio2 :3a :4a,b is 10 : 1 : 2).cis-exo-9-Dipropylborylbicyclo[6.1.01nona-2,4,6-triene (3b) is an intermediate product of the rearrangement; it is formed as a result of 8π-electrocyclization inE,Z,Z,Z-cyclononatetraenyl(dipropyl)boranela. The transformation of bicycle3b to final product 2 occurs apparently via a synchronous exchange of the groups at the B atom (the transformation of the cyclopropane ring to the boracyclobutane ring accompanied by simultaneous migration of the propyl group from the B atom to thea-C atom). Borane6 formed in this rearrangement rapidly isomerizes to2via a [1,3]-B shift.

Dynamic models of parallel computations for macropipelined programs

We have considered dynamic models of parallel computations and transformation algorithms for macropipelined programs that increase the internal exchange asynchronism of the parallel components. The models generalize the well-known CSP synchronous exchange paradigm (the rendezvous mechanism) [18] and provide a theoretical justification for the development of a whole range of interconnected semantic models of asynchronous computation with increasing degree of exchange asynchronism. Some publications ensure asynchronous exchange only by buffering [15, 16]. The dynamic model approach developed in this study combines buffering and analysis of data dependences of the exchange operators. It not only reduces losses associated with synchronization of communicating parallel processes, but also ensures automatic resolution of some classes of data exchange deadlocks. Experience with dynamic models as a means of increasing the efficiency of macropipelined programs and multilevel memory in multiprocessor systems [12, 17] can be applied in other programming systems and parallel program design systems of both compiling (S1, S2) and interpreting (S3) type.

Cooperative interaction of hydrogen bonds in proton exchange between the bases of nucleic acids

The tautomeric equilibrium in the H-bonded pair guanine-cytosine was studied by the semiempirical MNDO/HB quantum-chemical method. It was shown that hydration of the bases leads to an appreciable reduction of the activation barrier in the synchronous exchange of protons between the bases. Desolvation of the active center of the polymerase reduces the probability of error in the synthesis of the complementary chain of the nucleic acid by ∼106 times. Deprotonation of the phosphate groups of the nucleotides destabilizes the transition state in proton exchange. The genetic information is conserved as a result of the formation of nucleoprotein complexes with an ionic bond between the phosphate residue of the saccharophosphate skeleton of the nucleic acid and an amino (imino) group of the protein.

Mechanism of hindered rotation of the trifluorosilyl group in trifluorosilyl 3,6-di-tert-butylorthosemiquinolate

In tetrahydrofurane, ligand permutation in trifluorosilyl 3,6-di-tert-butylorthosemiquinolate is the result of bimolecular synchronous exchange of THF molecules between the radical complex and the solvent.

IR spectra of catalysts and adsorbed molecules. Communication 34. Interaction of n-hexane and deuterated methane with surface oh and od groups of acidic component of platinized alumina catalyst

1. In the IR spectrum of the hydrate-hydroxyl cover of γ-Al2O3, from five to ten absorption bands are observed, pertaining to hydroxyl groups with different reactivities in the reaction of deuterium-hydrogen exchange with tetradeutromethane. 2. On the γ-Al2O3 surface, n-hexane interacts with the high-frequency hydroxyl groups through a hydrogen-bonding mechanism, with a shift of the absorption bands toward the low-frequency region of the spectrum by 100-30 cm−1; the higher the frequency of the OH groups, the greater the shift. The n-hexane molecules do not interact with the low-frequency OH groups or with molecules of coordination-bonded water. 3. In the act of deuterium-hydrogen exchange between hydroxyl groups of the surface and an adsorbed molecule of a deuterohydrocarbon, the reactive species is an adsorbed state with a lifetime comparable to the time for transfer of a proton from a surface hydroxyl group to the hydrocarbon molecule. 4. In exchange with tetradeuteromethane, synchronous exchange of acidic and basic hydroxyl groups is observed, analogous to the same sort of pair removal of hydroxyl groups from the surface when it is dehydroxylated.

Multiconjugant Complexes of Euplotes Crassus: an Instance of Coordination of Nuclear Events*,†

SYNOPSIS In the ciliate Euplotes crussus, doublet cells of 3 complementary mating types were mixed and multiconjugant complexesobtained. The cells were not uniform in the G, stage at the time of mixing. Despite asynchrony, the nuclear events of conjugationstarted and progressed coordinately in all the members of each complex, leading to a synchronous exchange of pronuclei. An adjustmentof the cellular timing takes place before the nuclei of multiconjugants begin dividing. This adjustment probably occurs through specificciliary contact during preconjugant interaction.