Symmetry and Topology of Twin Boundaries and Five-Fold Twin Boundaries in Soft Crystals.

Heteroclusters constructed by tethering dissimilar nanoclusters using organic linkers resemble lipids and self-assemble into cubosomes, namely, microparticles of soft crystals composed of unique nanochannel lattices with a defined symmetry and topology. The internal porous crystal structures can be accurately characterized using transmission electron microscopy. We herein describe twin boundaries and five-fold twin boundaries in cubosomes with a double-diamond Pn3̅m structure. Our analysis indicates a clear distinction in the conformation of the skeletal unit: a centrosymmetric staggered conformation with point group D3d for the normal skeletal unit and a mirror-symmetric eclipsed one with point group D3h for the skeletal unit on the twin boundary. This symmetry distinction causes the channels to change direction and elongate slightly as they pass through the twin boundary, but the topology is maintained. For cubosomes containing five-fold twin boundaries, one of the channels is in the center of the particles seamlessly connecting the five blocks. Our conclusion is that the two distinct channel systems are still continuous. This fundamental understanding will contribute to the development of soft crystals with defined shapes and special inner nanostructures for advanced applications.

Unraveling the Self-Assembly of Heterocluster Janus Dumbbells into Hybrid Cubosomes with Internal Double-Diamond Structure.

Cubosomes are bicontinuous cubic-phase particles generated by amphiphile self-assembly with bicontinuous cubic phases, which creates an intricate network of interconnected nanochannels that endow these materials with special functions for advanced applications. On the other hand, clusters are an attractive class of molecules that exhibit intriguing functions and properties that differ from those of atoms and nanoparticles. Inspired by lipid self-assembly and attracted to the new functionalities of clusters, we prepared special heterocluster Janus dumbbells (HCJDs) composed of dissimilar nanoclusters: namely, a polyoxometalate and a polyhedral oligomeric silsesquioxane. HCJDs resemble conventional amphiphiles and, as such, they self-assemble in solution into faceted hybrid cubosomes via the transformation of vesicles into spongelike aggregates. Multiple mechanisms that lead to equilibrium, including molecular self-assembly, vesicle accumulation, membrane fusion, inner-structure reorganization, and cubic crystal growth, contributed to the overall process. On the basis of these results, we proposed a strategy for self-assembly-from basic molecular design that goes beyond traditional amphiphiles to the construction of micro- or nanomaterials with hierarchical structures and advanced functions.

Nonanalyticities of thermodynamic functions in finite noninteracting Bose gases within an exact microcanonical ensemble.

Within an exact microcanonical (MC) ensemble, we study the nonanalyticities of thermodynamic functions research in finite noninteracting Bose gases in traps. The results show that there exists a rich oscillatory behavior of MC thermodynamical quantities as a function of a system's total energy E (e.g., nonmonotonous temperature, nonanalytic and negative specific heats, and microscopic phase transitions). The origin of these nonanalyticities comes directly from the inverted curvature entropy S(E) with respect to E and the behaviors are different in different trap geometries, boundary conditions, and energy spectrum configurations. Contrary to the usual grandcanonical and canonical results, there exists Bose condensation and the nonanalyticities in the two-dimensional finite noninteracting Bose systems with different traps. We also discuss the critical temperature dependence on the particle number N with different ensembles, traps, and boundary conditions. In large enough N, almost all the results of the thermodynamical quantities become smooth, which are similar to the usual canonical behaviors. We emphasize the finite-size effects on the MC entropy change, which should, in principle, be observable in suitably designed experiments of the small systems.

Association of fibrinogen and fibrinogen gene beta148 and beta854 polymorphisms with coronary heart disease.

BACKGROUND: The aim of this study was to observe the association between fibrinogen C148T, G854A polymorphisms and plasma fibrinogen levels in a large cohort of Chinese patients with coronary heart disease (CHD). METHODS: Fibrinogen gene beta148/beta854 polymorphisms were screened and plasma fibrinogen levels and lipids were measured in patients with angiographically confirmed CHD (n = 836) and in controls without CHD (n = 418). RESULTS: Age, sex, smoking, hypertension, diabetes mellitus, blood lipids and fibrinogen levels were related to CHD (all p < 0. 05) while the frequencies of fibrinogen beta148 and beta854 alleles, gene and genotypes between the two groups were similar (all p > 0.05). CONCLUSION: This study demonstrates that the plasma fibrinogen level, but not fibrinogen beta148 and beta854 genotypes, was associated with CHD in the Chinese population.

[Beta-blocker therapy in the management of malignant ventricular arrhythmia in patients with acute myocardial infarction].

OBJECTIVE: To evaluate the clinical effectiveness of beta-blocker therapy on malignant ventricular arrhythmia in patients with acute myocardial infarction (AMI). METHODS: Beta-blockers, atenolol or betaloc, were given at the doses of 3.125 to 12.500 mg twice or 3 times a day (Bid or Tid) for management of malignant ventricular arrhythmia in 6 patients with AMI on the basis of conventional therapy. Increasing dosage of 25 to 50 mg was later initiated according to the patients' condition. In 2 cases that failed to respond to conventional antiarrhythmic, esmolol was administered via intravenous injection (5-10 mg) to control malignant ventricular arrhythmia within approximately 30 min, followed by a 2-day course of intravenous infusion at the rate of 1 to 2 mg/min. RESULTS: Five AMI patients survived while death occurred in 1 case due to heart failure. No deterioration of the cardiac function or proarrhythmic effect was observed in the 5 survival cases, but the occurrence of transient hypotension in 2 cases in the early stage of beta-blocker application and death due to cardioc insufficiency in one. CONCLUSION: Adequate use of beta-blockers is necessary in the early stage of AMI for effective control of malignant ventricular arrhythmia and lowering the mortality.