Does Statin Use in Frail Patients Provide Survival Benefits? Insights From a Meta-Analysis.

Frailty is a complex syndrome that increases with age and predisposes older adults to adverse outcomes, including mortality. Statins are proven to lower the risk of atherosclerotic cardiovascular disease, but there is limited data on their survival benefit in frail older people. This meta-analysis was conducted to determine whether statins can lower mortality in frail persons. A comprehensive search of PubMed, Google Scholar, and SCOPUS was conducted until September 2022 to identify studies reporting mortality outcomes with statin therapy in adults aged 75 with a validated frailty assessment. The pooled odds ratio for all-cause mortality was calculated using a random effects model. Leave-one-out method was used for sensitivity analysis. Of 5 studies (2013-2022) included (Total = 14,324, 3 prospective and 2 retrospectives, Males: 49%, Mean follow-up duration: 4.7 years), 41.6% (5971/14,324) were frail. 52.7% of patients were on a moderate-dose/no-statin, while 47.2% took a high-dose statin. Nonstatin users were older (83.35 vs 81.5) than users. Frail patients often had diabetes, hypertension, hyperlipidemia, a history of Stroke/MI, and dementia. High-dose atorvastatin was the most used statin. Pooled analysis revealed that statins lower all-cause mortality in elderly adults, however, the association was not significant (OR 0.67, 95% CI 0.38-1.18; P = 0.17). The meta-analysis demonstrated that using statins to reduce mortality in frail patients does not appear justifiable. Further prospective studies are needed to guide statin use among frail older adults for survival benefits.

Time-moduated nonreciprocal metasurface absorber for surface waves.

We have investigated a magnet-free, nonreciprocal surface wave absorber based on high impedance surfaces (HISs) using a spatial-temporal modulation approach. By controlling embedded switches with a travelling wave, the HIS metasurface is modulated to break the time and spatial symmetry, which enables surface waves to propagate in one direction but be absorbed when propagating in the reverse direction. The nonreciprocity has been demonstrated by an EM-circuit co-simulation. We envision that this could be possibly applied in future communication systems that preferably transmit unidirectionally but absorb interference from the reverse direction caused by reflections or other devices.

Integrating microsystems with metamaterials towards metadevices.

Electromagnetic metamaterials, which are a major type of artificially engineered materials, have boosted the development of optical and photonic devices due to their unprecedented and controllable effective properties, including electric permittivity and magnetic permeability. Metamaterials consist of arrays of subwavelength unit cells, which are also known as meta-atoms. Importantly, the effective properties of metamaterials are mainly determined by the geometry of the constituting subwavelength unit cells rather than their chemical composition, enabling versatile designs of their electromagnetic properties. Recent research has mainly focused on reconfigurable, tunable, and nonlinear metamaterials towards the development of metamaterial devices, namely, metadevices, via integrating actuation mechanisms and quantum materials with meta-atoms. Microelectromechanical systems (MEMS), or microsystems, provide powerful platforms for the manipulation of the effective properties of metamaterials and the integration of abundant functions with metamaterials. In this review, we will introduce the fundamentals of metamaterials, approaches to integrate MEMS with metamaterials, functional metadevices from the synergy, and outlooks for metamaterial-enabled photonic devices.

Optical homogeneity measurement of parallel plates by wavelength-tuning interferometry using nonuniform fast Fourier transform.

Wavelength-tuning interferometry is commonly employed to measure the optical homogeneity of parallel plates. However, the nonlinearity of phase shifts caused by wavelength tuning errors and environmental vibration leads to a spatially uniform error in the calculated phase distribution. Herein, a wavelength-tuning interferometry method based on nonuniform fast Fourier transform (WTI-NUFFT) was developed, which solves the spectral aliasing resulting from the spatially uniform error. The characteristics of the WTI-NUFFT method were estimated through comparison with the FFT method. Both the simulated and experimental results showed that the WTI-NUFFT method can improve the accuracy of the optical homogeneity measurement of parallel plates.

Plasmonic heating induced by Au nanoparticles for quasi-ballistic thermal transport in multi-walled carbon nanotubes.

The plasmon resonances of nanostructures enable wide applications from highly sensitive sensing to high-resolution imaging, through the improvement of photogeneration rate stimulated by the local field enhancement. However, quantitative experimental studies on the localized heating and the thermal transport process in the vicinity of plasmonics are still lacking because of the diffraction limit in conventional optothermal methodologies. In this work, we demonstrate an approach based on Raman thermometry to probe the near-field heating caused by plasmonics. An array of Au nanoparticles (AuNPs) fabricated by the template-assisted method is used to generate the near field effect. Multi-walled carbon nanotubes (MWCNTs) dispersed on the AuNPs are employed to quantify the near-field heating from their Raman peak shifts. Results show that the temperature rise in MWCNTs on AuNPs is much higher than that in a control group under the same laser irradiation. Further analysis indicates that the enhanced photon absorption of MWCNTs attributed to plasmon resonances is partially responsible for the different heating effect. The nonuniform thermal hot spots at the nanoscale can result in the quasi-ballistic thermal transport of phonons in MWCNTs, which is another reason for the temperature rise. Our results can be used to understand plasmonic heating effects as well as to explore quasi-ballistic thermal transport in carbon-based low-dimensional materials by tailoring the geometry or size of plasmonic nanostructures.

Implementing infrared metamaterial perfect absorbers using dispersive dielectric spacers.

A typical metamaterial perfect absorber (MPA) is comprised of a metamaterial layer, a dielectric spacer, and a ground plane. The conventional spacer material is usually a lossy dielectric with little-dispersion for the purpose of easing the design and optimization procedure of the MPA. In this paper, we present the design, fabrication, and characterization of metamaterial perfect absorbers with a highly dispersive spacer, which is compatible with functional microelectromechanical systems. The measured dispersive permittivity of a silicon nitride thin film is used in modeling the absorption response of MPAs with rigorous coupled wave analysis. Different designs of MPA structures are fabricated and characterized. Spectroscopy data shows two perfect absorption peaks in wavelengths ranging from 8 µm to 20 µm, which supports the theoretical calculation and numerical simulation. The dispersion of silicon nitride enables the shared resonant modes of the two peak wavelengths and decreases the wavelength shift led by variations in structural parameters. We demonstrate that the use of dispersive dielectric materials in MPAs potentiates various functional devices.

Silica Nanowire Growth on Coscinodiscus Species Diatom Frustules via Vapor-Liquid-Solid Process.

Diatom frustules are a type of porous silicon dioxide microparticle that has long been used in applications ranging from biomedical sensors to dye-sensitized solar cells. The favorable material properties, enormous surface area, and enhanced light scattering capacity support the promise of diatom frustules as candidates for next generation biomedical devices and energy applications. In this study, the vapor-liquid-solid (VLS) method is employed to incorporate silica nanowires on the surface of diatom frustules. Compared to the original frustule structures, the frustule-nanowire composite material's surface area increases over 3-fold, and the light scattering ability increases by 10%. By varying the gold catalyst thickness during the VLS process, tuning of the resultant nanowire length/density is achieved. Through material characterization, it is determined that both float growth and root growth processes jointly result in the growth of the silica nanowires. From a thermodynamics point of view, the preferential growth of the silica nanowires on frustules is found to have resulted from the enormous partial surface area of gold nanoparticles on the diatom frustules. The frustule-nanowire composite materials have potential applications in the development of novel biomedical sensing devices and may greatly enhance next generation solar cell performance.

Trimetazidine suppresses oxidative stress, inhibits MMP-2 and MMP-9 expression, and prevents cardiac rupture in mice with myocardial infarction.

BACKGROUND/AIMS: Cardiac rupture (CR) is a catastrophic complication of acute myocardial infarction (MI). At present, there are no effective pharmacological strategies for preventing post-MI rupture. Here we investigated the effect of trimetazidine (TMZ) on post-MI CR. METHODS: MI models were induced by left coronary artery ligation in male C57BL/6 mice. Animals allocated to the rupture incidence were closely monitored for 7 days; autopsy was performed once animals were found dead to determine the reason of death. Heart function was detected by echocardiography. Oxidative stress markers and matrix metalloproteinases (MMPs) were analyzed by Western Blotting. RESULTS: TMZ markedly reduced the post-MI CR incidence of mice. We found that the expression of metalloproteinase (MMP) -2 and MMP-9 in the TMZ-treated group was significantly lower than the saline-treated group. Further, TMZ markedly attenuated MI-induced oxidative stress. To investigate the mechanism of the effect of TMZ on CR, we pretreated H9c2 cells with H2 O2 and found that TMZ treatment markedly decreased H2 O2 -induced MMP-2 and MMP-9 expression. TMZ prevents CR through inhibition of oxidative stress, which is attributable to the down-regulation of MMP-2, MMP-9 expression. CONCLUSIONS: Our findings indicate that TMZ suppresses oxidative stress, inhibits MMP-2 and MMP-9 expression, and prevents CR in mice with MI.

Safety of early discharge after primary angioplasty in low-risk patients with ST-segment elevation myocardial infarction: A meta-analysis of randomised controlled trials.

Background Early discharge after successful primary angioplasty is common, but the evidence supporting the practice is still lacking. We therefore performed a meta-analysis assessing the safety of early discharge after primary angioplasty in low-risk patients with ST-segment elevation myocardial infarction (STEMI). Methods Randomised controlled trials were identified and extracted from PubMed, Embase, Cochrane Library databases and reference lists of relevant papers. Heterogeneity was analysed using the I2 test. If there was a lack of heterogeneity, fixed effects models would be used for the meta-analysis, otherwise random effects models were used. Statistical analyses were performed using Review Manager 5.3. Results Five randomised controlled trials involving 1575 STEMI patients met the criteria. Meta-analysis showed that the early discharge strategy group had a significantly shortened length of hospital stay compared to the conventional discharge strategy group (standardised mean difference -1.46, 95% confidence interval (CI) -2.04 to -0.88; P < 0.0001), and there was no difference in mortality and readmission rates between the two groups (risk ratio 0.78, 95% CI 0.50 to 1.22; P = 0.41). Conclusions The findings of this meta-analysis suggested that the early discharge strategy after successful primary angioplasty is safe among selected low-risk STEMI patients. A shorter hospital stay could benefit both the patients and the healthcare systems.

Beta-blockers reduced the risk of cardiac rupture in patients with acute myocardial infarction: A meta-analysis of randomized control trials.

BACKGROUND: Cardiac rupture (CR) is a catastrophic complication that occurs after acute myocardial infarction (MI) and, at present, there are no effective pharmacological strategies for preventing this condition. The objective of this meta-analysis was to assess the effect of beta-blockers on CR in patients with acute MI. METHODS: An extensive search of the PUBMED, EMBASE, ISI Web of Science, MEDLINE and Cochrane was performed to retrieve the studies of beta-blockers treatment in patients with acute MI. Data were combined using a random effects model. A meta-analysis was performed using Review Manager 5.3. RESULTS: Four randomized controlled trials (RCTs) involving 68, 842 patients, 603 of whom occurred CR, were met criteria. Meta analysis showed that beta-blockers caused a statistically and clinically significant decrease in the incidence of CR of 32% (RR: 0.68, 95% CI: 0.47 to 0.99, P=0.04). CONCLUSIONS: The findings of this meta-analysis confirmed that the early use of beta-blockers is associated with decreased incidence of CR, suggesting some beneficial effects of beta-blockers on infarct healing after acute MI.

Experimental study of the interaction between DC discharge microplasmas and CW lasers.

A high power (~ 1W) continuous wave (CW) laser was focused on argon microplasma generated in the microgap between two electrodes with submillimeter diameters. Dependence of breakdown (V(BD)) and quench (V(Q)) voltages of microplasma to the laser power, wavelength, and spot location were studied as the gap size and pressure varied. It was observed that the laser-plasma interaction can only occur thermally through the electrodes. Also, the thermal effect of the laser was noticeable at relatively higher pressures (> 10Torr), and in most cases led to a decrease in V(BD), proportional to the pressure.

Towards uniformly oriented diatom frustule monolayers: Experimental and theoretical analyses.

Diatoms are unicellular, photosynthetic algae that are ubiquitous in aquatic environments. Their unique, three-dimensional (3D) structured silica exoskeletons, also known as frustules, have drawn attention from a variety of research fields due to their extraordinary mechanical properties, enormous surface area, and unique optical properties. Despite their promising use in a range of applications, without methods to uniformly control the frustules' alignment/orientation, their full potential in technology development cannot be realized. In this paper, we realized and subsequently modeled a simple bubbling method for achieving large-area, uniformly oriented Coscinodiscus species diatom frustules. With the aid of bubble-induced agitations, close-packed frustule monolayers were achieved on the water-air interface with up to nearly 90% of frustules achieving uniform orientation. The interactions between bubble-induced agitations were modeled and analyzed, demonstrating frustule submersion and an adjustment of the orientation during the subsequent rise towards the water's surface to be fundamental to the experimentally observed uniformity. The method described in this study holds great potential for frustules' engineering applications in a variety of technologies, from sensors to energy-harvesting devices.

Culture and motion analysis of diatom Bacillaria paradoxa on a microfluidic platform.

We proved the feasibility of using a microfluidic chip to culture diatom Bacillaria paradoxa, and analyzed the gliding characteristics of its self-organized colony in detail. The optimal cultivation parameters of B. paradoxa for the designed chip made with polydimethylsiloxane are as follows: the preferable cells injecting rate for keeping the cells alive is 0.2 mL/h, the initial cell density for fast reproduction is 5.5 × 10(4) cells/mL, and the optimal replacement period of culture medium is 4 days. B. paradoxa tends to form a colony during their growth, and the colony can glide with a steady period of 29 ± 3 s along its axial direction in a constant stream, the amplitude of the colony will not decay (e.g., 24 µm of two-cell colony at 1.1 mm/s flow rate), and the colony rapidly adjusts its direction of gliding to the direction of water flow. The successful culture of diatoms on a microfluidic platform may be used for biosensing chips and the creation of gasoline-producing diatom solar panels.

Biosilica structures obtained from Nitzschia, Ditylum, Skeletonema, and Coscinodiscus diatom by a filtration-aided acid cleaning method.

A filtration-aided acid cleaning method was used to collect biosilica structures from a diatom culture medium, natural seawater, or water bloom. Cell extraction, acid cleaning, and acid removal were all performed on a polytetrafluoroethylene (PTFE) filter cloth, significantly improving the treatment capacity and efficiency of the traditional acid wash method. Five typical diatoms were cultivated in the laboratory for acid cleaning. Different growth speeds were introduced, and different process parameters for acid cleaning were utilized. After the acid cleaning, biosilica structures were collected from the frustules of diatoms using different methods. Girdle bands and valves of Coscinodiscus sp. were separated by floating of the valves. Central spines of Ditylum brightwellii and valves of Skeletonema costatum were separately collected by settling or filtration. Rod-like frustules, such as those of Bacillaris paradoxa, are not suitable for large quantities of acid wash. The silica structures were observed and tested using an AFM-calibrated glass needle to determine their elasticity. Elasticity tests showed that ringent girdle bands are more flexible than complete ones (Coscinodiscus sp.) and that both long-chain clusters of Nitzschia palea and central spines of D. brightwellii have certain elasticities. The required pressure for deforming or breaking the biosilica structures of diatoms was also determined.