Emulsification mechanism in an ultrasonic microreactor: Influence of surface roughness and ultrasound frequency

Microfluidic generation of nanoparticles using standing wave induced ultrasonic spray drying

Spray drying is a well-established process for generating particles for various applications, including pharmaceuticals. In this process, atomization plays a crucial role by defining the size of the droplets and, consequently, particle size. While ultrasound is commonly used to enhance atomization by reducing droplet size, a novel approach has been introduced that utilizes plug flow to generate plugs resonating with an applied ultrasound frequency, triggering surface atomization. This study investigates the applicability of this method for microfluidic atomization and spray drying, particular for pharmaceutical carrier particles. The generated droplets exhibit a size of 7.24 μm and a PDI of 0.18, indicating a monodisperse distribution. The droplets are produced in discrete burst events, enabling an energy-efficient pulsed process with an applied power of less than 1 W. This approach successfully generates lipid nanoparticles with an average size of 140 nm, underscoring its potential for nanoparticle production.

Enhancing verapamil trace determination from biological matrices by bar adsorptive microextraction

Verapamil is an L-type calcium channel blocker widely used in the treatment of cardiovascular diseases such as hypertension, angina and arrhythmias, requiring accurate therapeutic monitoring to maintain plasma, urine and saliva concentrations within a safe range. In this context, a novel analytical approach has been proposed to determine verapamil in biological samples, using bar adsorptive microextraction coated with reversed-phase polymers followed by high-performance liquid chromatography with diode array detection. Two adsorbents have been chosen, i.e. STRATA-CN and ENVI-18 polymers, showing recoveries from 56.01 ± 2.16% to 96.82 ± 0.61% under optimized experimental conditions, such as sample pH: 10.0 (STRATA-CN) and 8.0 (ENVI-18), 2 h of equilibrium time, stirring speed at 990 rpm, back-extraction solvent using methanol:acetonitrile (1 : 1 v/v), and 1 h under sonication. The analytical method showed linearity from 20 to 600 ng mL-1 (r ≥ 0.99), as well as adequate precision (with RSD% below 15%) and accuracy (with RE% within 15% of the nominal value). Finally, the analytical method was applied to plasma, urine and saliva samples and proved to be a promising alternative for the trace analysis of verapamil in biological matrices.

The efficacy of tobramycin dexamethasone combined with pranoprofen in middle-aged and elderly post-cataract patients and the value of improving inflammatory factor levels

OBJECTIVE

To analyze the effect of tobramycin dexamethasone combined with pranoprofen on middle-aged and elderly patients after cataract surgery.

METHODS

In this retrospective study, the clinical data from 108 middle-aged and elderly patients who had cataract surgery in the Second Hospital of Longyan between January 2021 and December 2023 were collected. The patients were divided into two groups based on treatment methods, a control group (n=54) that received tobramycin dexamethasone treatment, and an observation group (n=54) that treated with additional pranoprofen. The treatment effects in the two groups were compared.

RESULTS

Significant differences were observed between the groups at 1 day, 1 week, 3 weeks, and 5 weeks post-treatment in terms of ocular symptom scores, signs scores, and intraocular pressure levels (all P < 0.05). The observation group demonstrated lower levels of inflammatory markers post-treatment (P < 0.05). Additionally, at 1 week, 3 weeks and 5 weeks after treatment, significant differences were noted in anterior chamber flare value, best-corrected visual acuity (BCVA), macular center thickness, degree of corneal edema, and posterior lens capsular opacity grading scores (all P < 0.05). The incidence of increased intraocular pressure and conjunctival congestion was 3.7% in the observation group, slightly lower than 7.41% in the control group (P > 0.05).

CONCLUSION

The combination of pranoprofen and tobramycin dexamethasone can improve the inflammatory reaction, ocular symptoms, anterior chamber flare value, macular center thickness, corneal oedema, and clarity of the posterior lens capsule in middle-aged and elderly cataract patients. This regimen also helps restore intraocular pressure and visual acuity of the patients, with relatively low adverse reactions, indicating an ideal clinical outcome.

Nanogels: Recent Advances in Synthesis and Biomedical Applications

In the context of advanced nanomaterials research, nanogels (NGs) have recently gained broad attention for their versatility and promising biomedical applications. To date, a significant number of NGs have been developed to meet the growing demands in various fields of biomedical research. Summarizing preparation methods, physicochemical and biological properties, and recent applications of NGs may be useful to help explore new directions for their development. This article presents a comprehensive overview of the latest NG synthesis methodologies, highlighting advances in formulation with different types of hydrophilic or amphiphilic polymers. It also underlines recent biomedical applications of NGs in drug delivery and imaging, with a short section dedicated to biosafety considerations of these innovative nanomaterials. In conclusion, this article summarizes recent innovations in NG synthesis and their numerous applications, highlighting their considerable potential in the biomedical field.

Study on the mechanism of ultrasonic cavitation effect on the surface properties enhancement of TC17 titanium alloy

In industrial production and scientific research, ultrasonic cavitation technology, with its outstanding physical and chemical processing capabilities, has been widely applied in fields such as material surface modification, chemical synthesis, and biotechnology, becoming a focal point of research and application. This article delves into the effects of different ultrasonic frequencies on cavitation outcomes through the combined use of numerical simulation, fluorescence analysis, and high-speed photography, specifically analyzing the quantitative improvement in the mechanical properties of TC17 titanium alloy under ultrasonic cavitation at frequencies of 20 kHz, 30 kHz, and 40 kHz. The study found that at an ultrasonic frequency of 20 kHz, the maximum expansion radius of cavitation bubbles can reach 51.4 μm, 8.6 times their initial radius. Correspondingly, fluorescence intensity and peak area also increased to 402.8 and 28104, significantly above the baseline level. Moreover, after modification by ultrasonic cavitation, the original machining marks on the surface of TC17 titanium alloy became fainter, with the emergence of new, uniformly distributed microfeatures. The microhardness of the material increased from 373.7 Hv to 383.84 Hv, 396.62 Hv, and 414.06 Hv, with a maximum improvement of 10.8 %. At the same time, surface height difference and roughness significantly decreased (to 3.168 μm and 0.61 μm respectively), with reductions reaching 45.1 % and 42.4 %, indicating a significant improvement in material surface quality. Notably, there is a negative correlation between the improvement of mechanical properties and ultrasonic frequency, suggesting that the improvement effects decrease as ultrasonic frequency increases. This research not only reveals the quantitative relationship between ultrasonic cavitation frequency and material surface modification effects but also provides a solid scientific basis and practical guidance for the application of ultrasonic cavitation technology in surface engineering, signifying the technology's potential for broad application in the future.

Recent progress in Porphyra haitanensis polysaccharides: Extraction, purification, structural insights, and their impact on gastrointestinal health and oxidative stress management

Porphyra haitanensis, a red seaweed species, represents a bountiful and sustainable marine resource. P. haitanensis polysaccharide (PHP), has garnered considerable attention for its numerous health benefits. However, the comprehensive utilization of PHP on an industrial scale has been limited by the lack of comprehensive information. In this review, we endeavor to discuss and summarize recent advancements in PHP extraction, purification, and characterization. We emphasize the multifaceted mechanisms through which PHP promotes gastrointestinal health. Furthermore, we present a summary of compelling evidence supporting PHP's protective role against oxidative stress. This includes its demonstrated potent antioxidant properties, its ability to neutralize free radicals, and its capacity to enhance the activity of antioxidant enzymes. The information presented here also lays the theoretical groundwork for future research into the structural and functional aspects of PHP, as well as its potential applications in functional foods.

Nanoscale Pickering emulsion food preservative films/coatings: Compositions, preparations, influencing factors, and applications

Pickering emulsion (PE) technology effectively addresses the issues of poor compatibility and low retention of hydrophobic active ingredients in food packaging. Nonetheless, it is important to recognize that each stage of the preparation process for PE films/coatings (PEFCs) can significantly influence their functional properties. With the fundamental considerations of environmental friendliness and human safety, this review extensively explores the potential of raw materials for PEFC and introduces the preparation methods of nanoparticles, emulsification technology, and film-forming techniques. The critical factors that impact the performance of PEFC during the preparation process are analyzed to enhance food preservation effectiveness. Moreover, the latest advancements in PE packaging across diverse food applications are summarized, along with prospects for innovative food packaging materials. Finally, the preservation mechanism and application safety have been systematically elucidated. The study revealed that the PEFCs provide structural flexibility, where designable nanoparticles offer unique functional properties for intelligent control over active ingredient release. The selection of the dispersed and continuous phases, along with component proportions, can be customized for specific food characteristics and storage conditions. By employing suitable preparation and emulsification techniques, the stability of the emulsion can be improved, thereby enhancing the effectiveness of the films/coatings in preserving food. Including additional substances broadens the functionality of degradable materials. The PE packaging technology provides a safe and innovative solution for extending the shelf life and enhancing the quality of food products by protecting and releasing active components.

Continuous generation of cross-linked polymer nanoparticles employing an ultrasonic microreactor

In this article, a new system employing an ultrasonic microreactor coupled with a tubular reactor is presented for the continuous generation of polymer nanoparticles. The continuous generation of cross-linked polymer nanoparticles utilizing the monomer butyl methacrylate and the cross-linker ethylene glycol dimethacrylate is demonstrated. Firstly, the miniemulsion polymerization of a monomer-in-water miniemulsion is studied in a batch system. Secondly, a coiled tubular reactor is employed for the continuous polymerization of the miniemulsion generated by an ultrasonic microreactor. Finally, the influence of monomer volume fraction and surfactant concentration on the synthesized polymer nanoparticles is studied. Polymer particles in a size range of 50-250 nm are synthesized and a high polymerization conversion is achieved utilizing the system demonstrated in this article.

A Liquid Mirror Resonator

We present the first experimental demonstration of a Fabry‒Perot resonator that utilizes total internal reflection from a liquid-gas interface. Our hybrid resonator hosts both optical and capillary waves that mutually interact. Except for the almost perfect reflection by the oil-air interface at incident angles smaller than the critical angle, reflections from the liquid-phase boundary permit optically examining thermal fluctuations and capillary waves at the oil surface. Characterizing our optocapillary Fabry‒Perot reveals optical modes with transverse cross-sectional areas of various shapes and longitudinal modes that are separated by the free spectral range. The optical finesse of our hybrid optocapillary resonator is Fo = 60, the optical quality factor is Qo = 20 million, and the capillary quality factor is Qc = 6. By adjusting the wavelength of our laser near the optical resonance wavelength, we measure the liquid's Brownian fluctuations. As expected, the low-viscosity liquid exhibits a distinct frequency of capillary oscillation, indicating operation in the underdamped regime. Conversely, going to the overdamped regime reveals no such distinct capillary frequency. Our optocapillary resonator might impact fundamental studies and applications in surface science by enabling optical interrogation, excitation, and cooling of capillary waves residing in a plane. Moreover, our optocapillary Fabry‒Perot might permit photographing thermal capillary oscillation, which the current state-of-the-art techniques do not support.