Risk of major bleeding and thromboembolism in Asian patients with nonvalvular atrial fibrillation using direct oral anticoagulants versus warfarin.

Background Bleeding and thromboembolism prevention is important in patients with nonvalvular atrial fibrillation receiving anticoagulants, including direct oral anticoagulants and warfarin. Asians have higher risks of bleeding complications when taking anticoagulants. However, evidence that considers laboratory parameters is lacking. Objective We aimed to compare the safety and effectiveness between direct oral anticoagulants and warfarin in Asian patients with nonvalvular atrial fibrillation. Setting Retrospective design using hospital-based data. Method This propensity score-matched cohort study included data extracted from the electronic medical records of the En Chu Kong Hospital Research Database. Main outcome measure Outcome measures were major bleeding and thromboembolism. Cox proportional hazard models were applied for evaluating hazard ratios with 95% confidence intervals. Results Among 1075 patients with nonvalvular atrial fibrillation, 687 and 388 were administered direct oral anticoagulants and warfarin, respectively. After propensity score matching, 264 patient pairs were selected. Compared with warfarin use, direct oral anticoagulant use was associated with similar risks for major bleeding and thromboembolism; however, the latter was associated with increased gastrointestinal bleeding risks (adjusted hazard ratio 3.59; 95% confidence interval, 1.31-11.39). Notably, an approximately 10 fold increased risk of gastrointestinal bleeding was observed in 0-6 month direct oral anticoagulant users (adjusted hazard ratio 10.13, 95% confidence interval 1.27-80.89). Conclusion Direct oral anticoagulant use was not associated with major bleeding and thromboembolism occurrence in Asian patients with nonvalvular atrial fibrillation. However, direct oral anticoagulant use was associated with increased gastrointestinal bleeding risks, especially when used within 0-6 months of direct oral anticoagulant use.

[Improving the Rate of Eating Safety Guidance Implementation Among the Elderly].

BACKGROUND & PROBLEM: The provision by nurses of effective swallowing assessments and eating safety guidance improves eating safety in the elderly. The authors of this study found that elderly clients experienced a high proportion of aspiration pneumonia after choking episodes and that the rate of implementation of eating safety guidance among these clients by nursing staff was only 64.6%. The problems identified included a lack of education and training related to eating safety for the elderly, inconsistent health education methods, oral health education only, lack of unified health education content, and lack of proper health education guidance aids. PURPOSE: To raise the rate of implementing eating safety guidance among the elderly from 64.6% to 90.0%. RESOLUTION: The project included promoting an eating safety guidance workflow for the elderly using cross-team collaboration, using human body models and food models, promoting oral healthcare and oral exercises, using multilingual instructional leaflets and videos on eating safety and hygiene education, promoting a treasure hunting activity to the elderly related to eating safely using a food texture selection chart, and implementing a workshop on simulated eating safety scenarios. RESULTS: After project implementation, the eating safety guidance implementation rate increased from 64.6% to 92.1%, demonstrating that the intervention measures achieved remarkable results. CONCLUSIONS: Formulating care procedures and cooperating across teams to draft concrete and feasible improvement measures effectively increased the rate of eating safety guidance implementation for elderly clients by nursing staff.

Effectiveness of palonosetron versus granisetron in preventing chemotherapy-induced nausea and vomiting: a systematic review and meta-analysis.

PURPOSE: Chemotherapy-induced nausea and vomiting (CINV) commonly occurs after chemotherapy, adversely affecting patients' quality of life. Recently, studies have shown inconsistent antiemetic effects of two common 5-hydroxytryptamine 3 receptor antagonists, namely, palonosetron and granisetron. Therefore, we conducted a meta-analysis to evaluate the effectiveness of palonosetron versus granisetron in preventing CINV. METHODS: Relevant studies were obtained from PubMed, Embase, and Cochrane databases. The primary outcome was the complete response (CR) rate. Secondary outcomes were headache and constipation events. RESULTS: In total, 12 randomized controlled trials and five retrospective studies were reviewed. Palonosetron was consistently statistically superior to granisetron in all phases in terms of the CR rate (acute phases: odds ratio [OR] = 1.28, 95% confidence interval [CI] = 1.06-1.54; delayed phases: OR = 1.38, 95% CI = 1.13-1.69; and overall phases: OR = 1.37, 95% CI = 1.17-1.60). Moreover, a non-significant difference was found between the two groups in terms of the headache event, but the occurrence of the constipation event was lower in the granisetron group than in the palonosetron group. CONCLUSION: Palonosetron showed a higher protective efficacy in all phases of CINV prevention, especially in delayed phases, and no relatively severe adverse effects were observed.

Rotationally induced fingering patterns in a two-dimensional heterogeneous porous medium.

Rotating fluid flows under two-dimensional homogeneous porous media conditions (or in a rotating Hele-Shaw cell) reveal the development of complex interfacial fingering patterns. These pattern-forming structures are characterized by the occurrence of finger competition events, finger pinch-off episodes, as well as by the production of satellite droplets. In this work, we use intensive numerical simulations to investigate how these fully nonlinear pattern growth phenomena are altered by the presence of permeability heterogeneities in the rotating porous medium. This is done by employing a diffuse-interface Darcy-Cahn-Hilliard description of the problem and considering a permeability field presenting a log-Gaussian distribution, characterized by a variance s and a correlation length l. We study how the heterogeneity measures s and l couple to the governing hydrodynamic dimensionless parameters of the problem and introduce important changes on the pattern formation dynamics of the system.

Magnetic microchains and microswimmers in an oscillating magnetic field.

Superparamagnetic micro-bead chains and microswimmers under the influence of an oscillating magnetic field are studied experimentally and numerically. The numerical scheme composed of the lattice Boltzmann method, immersed boundary method, and discrete particle method based on the simplified Stokesian dynamics is applied to thoroughly understand the interaction between the micro-bead chain (or swimmer), the oscillating magnetic field, and the hydrodynamics drag. The systematic experiments and simulations demonstrated the behaviors of the microchains and microswimmers as well as the propulsive efficiencies of the swimmers. The effects of key parameters, such as field strengths, frequency, and the lengths of swimmer, are thoroughly analyzed. The numerical results are compared with the experiments and show good qualitative agreements. Our results proposed an efficient method to predict the motions of the reversible magnetic microdevices which may have extremely valuable applications in biotechnology.

Enhanced mixing via alternating injection in radial Hele-Shaw flows.

Mixing at low Reynolds numbers, especially in the framework of confined flows occurring in Hele-Shaw cells, porous media, and microfluidic devices, has attracted considerable attention lately. Under such circumstances, enhanced mixing is limited due to the lack of turbulence, and absence of sizable inertial effects. Recent studies, performed in rectangular Hele-Shaw cells, have demonstrated that the combined action of viscous fluid fingering and alternating injection can dramatically improve mixing efficiency. In this work, we revisit this important fluid mechanical problem, and analyze it in the context of radial Hele-Shaw flows. The development of radial fingering instabilities under alternating injection conditions is investigated by intensive numerical simulations. We focus on the impact of the relevant physical parameters of the problem (Péclet number Pe, viscosity contrast A, and injection time interval Δt) on fluid mixing performance.

Radial Hele-Shaw flow with suction: fully nonlinear pattern formation.

We study the development of intricate, fully nonlinear immiscible interfacial patterns in the suction-driven radial Hele-Shaw problem. The complex-shaped, contracting fluid-fluid interface arises when an initially circular blob of more viscous fluid, surrounded by less viscous one, is drawn into an eccentric point sink. We present sophisticated numerical simulations, based on a diffuse interface model, that capture the most prominent interfacial features revealed by existing experimental studies of the problem. The response of the system to changes in the capillary number is investigated, accurately revealing the occurrence of finger competition phenomena, and correctly describing the velocity behavior of both inward- and outward-pointing fingers. For the large-capillary-number regime, a set of complex interfacial features (finger merging, shielding, and pinch-off) whose experimental realization is still not available, are predicted.

Selection and characterization of vaccine strain for Enterovirus 71 vaccine development.

Enterovirus 71 (EV71) has recently emerged as an important neurotropic virus in Asia because effective medications and prophylactic vaccine against EV71 infection are not available. Based on the success of inactivated poliovirus vaccine, the Vero cell-based chemically inactivated EV71 vaccine candidate could be developed. Identification of EV71 vaccine strain which can grow to high titer in Vero cell and induce cross-genotype virus neutralizing antibody responses represents the first step in vaccine development. In this report we describe the characterization and validation of a clinical isolate E59 belonging to B4 sub-genotype based on VP1 genetic analysis. Before selected as the vaccine strain, the genetic stability of E59 in passage had been analyzed based on the nucleotide sequences obtained from the Master Virus Seed, Working Seed banks and the virus harvested from the production lots, and found to be identical to those found in the original isolate. These results indicate that E59 vaccine strain has strong genetic stability in passage. Using this vaccine strain the prototype EV71 vaccine candidate was produced from 20L of Vero cell grown in serum-containing medium. The production processes were investigated, characterized and quantified to establish the potential vaccine manufacturing process including the time for virus harvest, the membrane for diafiltration and concentration, the gel-filtration chromatography for the down-stream virus purification, and the methods for viral inactivation. Finally, the inactivated virion vaccine candidate containing sub-microgram of viral proteins formulated with alum adjuvant was found to induce strong virus neutralizing antibody responses in mice and rabbits. Therefore, these results provide valuable information for cell-based EV71 vaccine development.

Diffuse-interface approach to rotating Hele-Shaw flows.

When two fluids of different densities move in a rotating Hele-Shaw cell, the interface between them becomes centrifugally unstable and deforms. Depending on the viscosity contrast of the system, distinct types of complex patterns arise at the fluid-fluid boundary. Deformations can also induce the emergence of interfacial singularities and topological changes such as droplet pinch-off and self-intersection. We present numerical simulations based on a diffuse-interface model for this particular two-phase displacement that capture a variety of pattern-forming behaviors. This is implemented by employing a Boussinesq Hele-Shaw-Cahn-Hilliard approach, considering the whole range of possible values for the viscosity contrast, and by including inertial effects due to the Coriolis force. The role played by these two physical contributions on the development of interface singularities is illustrated and discussed.

Controlling radial fingering patterns in miscible confined flows.

Injection-driven immiscible flow in radial Hele-Shaw cells results in highly ramified patterns if the injection rate is constant in time. Likewise, time-dependent gap immiscible flow in lifting Hele-Shaw cells leads to intricate morphologies if the cell's gap width grows exponentially with time. Recent studies show that the rising of these complex fingered structures can be controlled by properly adjusting the injection rate, and the time-dependent gap width. We investigate the effectiveness of these control strategies assuming that the fluids involved are miscible. Despite the absence of surface tension effects, intensive numerical simulations support the stabilizing role of these controlling protocols. Splitting, merging and competition of fingers are all inhibited. The sensitivity of the system to changes in the initial conditions and Péclet numbers is also discussed.

Magnetically induced spreading and pattern selection in thin ferrofluid drops.

We report an experimental study of a fingering pattern formation which occurs during the spreading of an immiscible thin ferrofluid drop subjected to a radial magnetic field. Our results indicate that this ferrohydrodynamic system works as a magnetic analog of conventional spin coating, where centrifugal driving is replaced with a magnetic body force induced by the radial applied field. In this context, a magnetically tunable pattern selection mechanism is proposed in which the shape and number of the arising fingered structures can be properly controlled.

Miscible ferrofluid patterns in a radial magnetic field.

Pattern formation in a miscible ferrofluid system is experimentally investigated. The experiment is performed by immersing a thin ferrofluid droplet in a cylindrical container, overfilling it with a nonmagnetic miscible fluid, and applying an in-plane radial magnetic field. Visually striking patterns are obtained whose morphologies change from circular at zero field to complex starburst-like structures at finite field. The evolution of miscible ferrofluid droplets of various initial diameters subjected to different magnetic-field strengths is considered. Proper rescaling of the experimental data indicates that the time evolution of the droplets' area increments obeys a universal 4/3 power-law behavior at long times.

Radial viscous fingering in miscible Hele-Shaw flows: a numerical study.

A modified version of the usual viscous fingering problem in a radial Hele-Shaw cell with immiscible fluids is studied by intensive numerical simulations. We consider the situation in which the fluids involved are miscible, so that the diffusing interface separating them can be driven unstable through the injection or suction of the inner fluid. The system is allowed to rotate in such a way that centrifugal and Coriolis forces come into play, imposing important changes on the morphology of the arising patterns. In order to bridge from miscible to immiscible pattern forming structures, we add the surface tensionlike effects due to Korteweg stresses. Our numerical experiments reveal a variety of interesting fingering behaviors, which depend on the interplay between injection (or suction), diffusive, rotational, and Korteweg stress effects. Whenever possible the features of the simulated miscible fronts are contrasted to existing experiments and other theoretical or numerical studies, usually resulting in close agreements. A number of additional complex morphologies, whose experimental realization is still not available, are predicted and discussed.

Hybrid ferrohydrodynamic instability: coexisting peak and labyrinthine patterns.

We present an experimental study of a different pattern-forming instability occurring when a ferrofluid droplet is immersed in a thin layer of a nonmagnetic fluid, and subjected to a uniform perpendicular magnetic field. The formation of intriguing interfacial structures is observed, and the development of a hybrid-type ferrohydrodynamic instability is verified, where peak and labyrinthine ferrofluid patterns coexist and share a coupled dynamic evolution. Based on our experimental findings we have identified the occurrence of three well defined regimes for the evolution of the miscible Rosensweig peak in which it first grows rapidly, and then gradually decays, to ultimately reimmerse into the surrounding nonmagnetic solvent layer. This unique scenario for the rise and fall of the Rosensweig peak implies the simultaneous emergence of peculiar labyrinthine structures induced by an outward radial flow within the thin nonmagnetic layer. A variety of possible morphologies is revealed (labyrinth, broken tentaclelike fingers, etc.), which result from the interplay between magnetic, diffusive, and convective effects. These free surface flow labyrinthine structures are contrasted to alternative interfacial designs obtained when the experimental system is spatially confined.

Fingering patterns in the lifting flow of a confined miscible ferrofluid.

Miscible flow displacements of a ferrofluid droplet subjected to various magnetic field configurations and confined in a time-dependent gap Hele-Shaw cell are examined through highly accurate numerical simulations. The interplay between lifting, miscibility, and applied magnetic fields resulted in complex interfacial pattern formation. By varying the symmetry properties of the applied magnetic fields and by considering the action of Korteweg stresses, a number of interesting droplet morphologies are identified and characterized. The possibility of controlling the degree of fluid mixing and the ultimate shape of the emerging patterns by appropriately adjusting the strength of the applied magnetic fields is also discussed.

Numerical study of pattern formation in miscible rotating Hele-Shaw flows.

The dynamics of the diffusing interface separating two miscible fluids in a rotating Hele-Shaw cell is studied by intensive and highly accurate numerical simulations. We perform numerical experiments in a wide range of parameters, focusing on the influence of viscosity contrast and Korteweg stresses on the shape of the interfacial patterns. A great variety of morphological behaviors is systematically introduced, and a wealth of interesting phenomena related to finger competition dynamics, filament stretching, and interface pinch off are reveal. Our simulations exhibit miscible patterns that bear a strong resemblance to their immiscible counterparts for larger Korteweg stresses. The quantitative equivalence between such stresses and the usual immiscible surface tension is studied. The concept of an effective interfacial tension is considered, allowing the direct and precise calculation of the important fingering properties under miscible circumstances. Our results show excellent agreement with existing experiments and simulations for corresponding immiscible displacements. This agreement refers to a striking similarity between miscible and immiscible pattern morphologies, and also to an accurate prediction for the typical number of miscible fingering structures formed. Our findings suggest that the effective interfacial tension is both qualitatively and quantitatively equivalent to its immiscible counterpart.

Numerical study of miscible fingering in a time-dependent gap Hele-Shaw cell.

We perform a detailed numerical study of the evolution of a miscible fluid droplet in a time-dependent gap Hele-Shaw cell. The development of the emerging fingering instabilities is systematically analyzed by intensive and highly accurate numerical simulations. We focus on the influence of three relevant physical parameters on the interface dynamics: the Pélclet number Pe, the viscosity contrast A, and the Korteweg stress parameter delta. Consistently with conventional miscible Saffman-Taylor studies in constant-gap Hele-Shaw cells, our results demonstrate that more vigorous fingering is observed at higher Pe and larger A. Concerning the specific role of Pe and A, we deduce two general results: higher Péclet number favors branching around a nearly circular region (which leads to longer interfacial lengths); while larger viscosity contrast results in more significant finger penetrations (which is quantitatively expressed by larger diameter of gyration). We have also verified that the Korteweg stress parameter delta does act as an effective interfacial tension: it stabilizes the miscible interface, leading to fingering patterns that present a greater resemblance with the structures obtained in similar immiscible situations. Finally, we have identified the development of a visually striking phenomenon in the limit of high Pe, large A , and relatively small delta: some outward fingers pinch, and subsequent droplet detachment is observed. We show that such a droplet detachment process can be prevented by the action of stronger interfacial stresses. This last finding provides additional evidence for the claim that the Korteweg stresses can be treated as an ersatz interfacial tension in diffusing fluids.