Manipulation of Particle/Cell Based on Compressibility in a Divergent Microchannel by Surface Acoustic Wave.

The mechanical properties (compressibility or deformability) of cells are closely related to their death, migration, and differentiation. Accurate separation and manipulation of bioparticles based on these mechanical properties are still a challenging in the field of acoustofluidics. In this work, based on surface acoustic waves (SAW) and divergent microchannels, we developed a new method for separating and detecting particles or cells with different compressibility. The difference in acoustic radiation force (Fr) caused by compressibility are gradually amplified and accumulated by decreasing the flow velocity, and they are finally reflected in the particle migration distance. During the transverse migration process, the alternating dominance of the acoustic radiation force and the Stokes resistance force (Fs) drives the particles to create three typical migration patterns: intermittent migration, compound migration, and near-wall migration. In the present tilted SAW device, a 91% separation success rate of ∼10 µm polystyrene (PS) and polydimethylsiloxane (PDMS) particles can be achieved by optimizing the acoustic field input power and the fluid velocity. The application potential of the present divergent microchannel is validated by separating the myelogenous leukemia cell K562 and the natural killer cell NK92 that have similar densities and sizes (∼15 µm) but different compressibility. The results of this work are expected to provide valuable insights into the acoustofluidics separation and detection of the cells that are with different compressibility.

Analysis of sputum microbial flora in chronic obstructive pulmonary disease patients with different phenotypes during acute exacerbations.

BACKGROUND: Increasing studies have shown that the imbalance of the respiratory microbial flora is related to the occurrence of COPD, the severity and frequency of exacerbations and mortality.However, it remains unclear how the sputum microbial flora differs during exacerbations in COPD patients manifesting emphysema phenotype, chronic bronchitis with emphysema phenotype and asthma-COPD overlap phenotype. METHODS: Sputum samples were obtained from 29 COPD patients experiencing acute exacerbations who had not received antibiotics or systemic corticosteroids within the past four weeks.Patients were divided into three groups;emphysema phenotype(E);chronic bronchitis with emphysema phenotype(B+E) and asthma-COPD overlap phenotype(ACO).We utilized metagenomic Next Generation Sequencing (mNGS) technology to analyze the sputum microbial flora in COPD patients with different phenotypes during exacerbations. RESULTS: There was no significant difference in alpha diversity and beta diversity among three groups.The microbial flora composition was similar in all three groups during exacerbations except for a significant increase in Streptococcus mitis in ACO.Through network analysis,we found Candidatus Saccharibacteria oral taxon TM7x and Fusobacterium necrophorum were the core nodes of the co-occurrence network in ACO and E respectively.They were positively correlated with some species and play a synergistic role.In B+E,Haemophilus pittmaniae and Klebsiella pneumoniae had a synergistic effect.Besides,some species among the three groups play a synergistic or antagonistic role.Through Spearman analysis,we found the relative abundance of Streptococcus mitis was negatively correlated with the number of hospitalizations in the past year(r = -0.410,P = 0.027).We also observed that the relative abundance of Prevotella and Prevotella melaninogenica was negatively correlated with age(r = -0.534,P = 0.003;r = -0.567,P = 0.001),while the relative abundance of Streptococcus oralis and Actinomyces odontolyticus was positively correlated with age(r = 0.570,P = 0.001;r = 0.480,P = 0.008).In addition,the relative abundance of Prevotella melaninogenica was negatively correlated with peripheral blood neutrophil ratio and neutrophil to lymphocyte ratio(r = -0.479,P = 0.009;r = -0.555,P = 0.002),while the relative abundance of Streptococcus sanguinis was positively correlated with peripheral blood neutrophil ratio and neutrophil to lymphocyte ratio (r = 0.450,P = 0.014;r = 0.501,P = 0.006).There was also a significant positive correlation between Oribacterium and blood eosinophil counts(r = 0.491,P = 0.007). CONCLUSION: Overall,we analyzed the sputum microbiota of COPD patients with different phenotypes and its relationship with clinical indicators, and explored the relationships between microbiota and inflammation in COPD.We hope to alter the prognosis of patients by inhibiting specific bacterial taxa related to inflammation and using guide individualized treatment in the future research.

Robust Hydrogel Adhesion by Harnessing Bioinspired Interfacial Mineralization.

Hydrogels have gained intensive interest in biomedical and flexible electronics, and adhesion of hydrogels to substrates or devices is indispensable in these application scenarios. Although numerous hydrogel adhesion strategies have been developed, it is still challenging to achieve a hydrogel with robust adhesion interface through a universal yet simple method. Here, a strategy for establishing strong interfacial adhesion between various hydrogels and a wide variety of substrates (i.e., soft hydrogels and rigid solids, including glass, aluminum, PET, nylon and PDMS) even under wet conditions, is reported. This strong interfacial adhesion is realized by constructing a bioinspired mineralized transition layer through ion diffusion and subsequent mineral deposition. This strategy is not only generally applicable to a broad range of substrates and ionic pairs, but also compatible with various fabrication approaches without compromising their interfacial robustnesses. This strategy is further demonstrated in the application of single-electrode triboelectric nanogenerators (TENG), where a robust interface between the hydrogel and elastomer layers is enabled to ensure a reliable signal generation and output.

Impact of medical adhesives on persistent fluid extravasation at needle injection sites in patients with severe edema: a randomized controlled trial.

OBJECTIVE: To investigate the efficacy of medical glue in halting fluid extravasation at needle insertion sites in patients with severe edema. METHODS: Sixty patients with severe edema were recruited between June 2022 and June 2023 and randomly allocated into either the control group or the experimental group, with 30 cases in each. In the experimental group, after intramuscular injection, medical glue was administered at the needle insertion site, and covered with gauze dressing upon curing, and subsequently subjected to pressure bandaging. Patients were instructed to limit their activity. Meanwhile, the control group received conventional nursing procedures involving pressure bandaging and activity restriction. The effectiveness of nursing interventions in halting exudation, duration of hospitalization, duration of exudation, nursing expenses, skin complications (infection, rash, abrasion, abnormal sensation, etc.), and patient satisfaction with nursing care were monitored. RESULTS: Comparison between the two groups revealed statistically significant differences in several aspects: the success rate of halting exudation, duration of exudation, total skin complication rate, and overall satisfaction [83.3% vs. 20.0%, (2.20 ± 2.76) days vs. (7.33 ± 3.28) days, 6.67% vs. 33.33%, 80.00% vs. 36.67%, P < 0.05]. However, there were no statistically significant differences in hospitalization time and nursing expenses [(14.50 ± 5.17) days vs. (14.00 ± 3.95) days, (537.53 ± 264.19) yuan vs. (661.97 ± 305.55) yuan, P > 0.05]. CONCLUSION: Medical glue demonstrates effectiveness in halting fluid extravasation at needle insertion sites among patients experiencing severe edema. Additionally, it reduces the duration of exudation, diminishes skin complications resulting from exudation, and significantly enhances patient satisfaction with nursing care. Given these benefits, its clinical adoption and application are highly recommended.

Er:YAG laser settings for debonding zirconia restorations: An in vitro study.

This in vitro study aimed to determine the optimal frequency and energy settings for debonding zirconia restorations using an erbium-doped yttrium aluminum garnet (Er:YAG) laser. A total of 200 zirconia specimens (5 mm × 5 mm × 1.5 mm) were fabricated from two types of materials: (1) 3 mol% yttria oxide stabilized tetragonal zirconia polycrystalline (3Y-TZP) and (2) 5 mol% yttria oxide stabilized tetragonal zirconia polycrystalline (5Y-TZP). The zirconia specimens were bonded to dentin using resin cement (RelyX Ultimate, 3 M) and divided into 20 groups based on their laser treatments (n = 5). Er:YAG laser treatment was applied at various frequencies (10 Hz and 20 Hz) and energies (80 mJ, 100 mJ, 120 mJ, 140 mJ, 160 mJ, 180 mJ, 200 mJ, 220 mJ, 240 mJ, and 260 mJ). The time required to debond the specimens and the temperature changes that dentin underwent during the laser treatment were recorded. The surface morphologies of the debonded dentin and zirconia specimens were observed using scanning electron microscopy (SEM). Additional zirconia specimens were fabricated for 4-point flexural strength testing and surface roughness measurements. Statistical analyses were conducted using three-way analysis of variance (ANOVA) and Student-Newman-Keuls (SNK)-q tests (α = 0.05). The debonding time of each specimen varied between 4.8 and 160.4 s, with an average value of 59.2 s. The dentin temperature change for each specimen ranged from 2.3 to 3.6 °C, with an average value of 2.7 °C. The debonding time was significantly influenced by the zirconia material type and laser energy, but it was not affected by the laser frequency. Among the specimens, those made of 3Y-TZP needed significantly more time for debonding than 5Y-TZP. The optimal energies were 220 mJ for 3Y-TZP and 200 mJ for 5Y-TZP. The laser frequency, laser energy, and type of zirconia material had no effect on the dentin temperature change. Additionally, no surface alternations were observed on the dentin or zirconia materials after laser treatment. The surface roughness and flexural strength of the zirconia materials remained unchanged after laser treatment. In summary, Er:YAG laser treatment effectively and safely removes zirconia restorations without impacting their mechanical properties, with a safe temperature change of less than 5.6 °C. The optimum frequency and energy settings for debonding 3Y-TZP and 5Y-TZP restorations were found to be 10/20 Hz and 220 mJ and 10/20 Hz and 200 mJ, respectively.

Self-Growing Hydrogel Bioadhesives for Chronic Wound Management.

Hydrogel bioadhesives have emerged as a promising alternative to wound dressings for chronic wound management. However, many existing bioadhesives do not meet the functional requirements for efficient wound management through dynamically mechanical modulation, due to the reduced wound contractibility, frequent wound recurrence, incapability to actively adapt to external microenvironment variation, especially for those gradually-expanded chronic wounds. Here, a self-growing hydrogel bioadhesive (sGHB) patch that exhibits instant adhesion to biological tissues but also a gradual increase in mechanical strength and interfacial adhesive strength within a 120-h application is presented. The gradually increased mechanics of the sGHB patch could effectively mitigate the stress concentration at the wound edge, and also resist the wound expansion at various stages, thus mechanically contracting the chronic wounds in a programmable manner. The self-growing hydrogel patch demonstrated enhanced wound healing efficacy in a mouse diabetic wound model, by regulating the inflammatory response, promoting the faster re-epithelialization and angiogenesis through mechanical modulation. Such kind of self-growing hydrogel bioadhesives have potential clinical utility for a variety of wound management where dynamic mechanical modulation is indispensable.

Microplastics and their interaction with microorganisms in Bosten Lake sediment.

Microplastics (MPs), discovered in oceans, lakes, and rivers, can infiltrate the food chain through ingestion by organisms, potentially posing health risks. Our research is the first to study the composition and distribution of MPs in Bosten Lake's sediment. In May, the average abundance of MPs was 0.95±0.72 particles per 10 gs, and in October, it was 0.90±0.61 particles per 10 gs. Bohu Town had the highest MP abundance, with 1.75±0.35 particles per 10 gs in spring and 2 ± 0 particles per 10 gs in autumn. In May, 53 % of the MPs were transparent, while in October, black MPs constituted 58 %. The predominant morphology was fibrous, accounting for 61 % of the total. MPs in the size range of 0.2-1 mm made up 91 % and 66 % of the total in May and October, respectively. The most common types of MPs in May were polyethylene terephthalate (PET) at 40 % and polyethylene (PE) at 26 %. In October, PET was the most prevalent at 71 %, followed by poly(ether-ether-ketone)(PEEK) at 11 %. Certain microbial taxa, such as Actinobacteriota, Pseudomonas, and Vicinamibacteraceae, associated with MP degradation or complex carbon chain breakdown, were notably enriched in sediment areas with high MP concentrations. A significant positive correlation was observed between the abundance of MPs in sediments and Actinobacteriota. Additionally, the abundance of Thiobacillus, Ca.competibacter, and other bacteria involved in soil element cycling showed a significant positive correlation with the organic matter content in the sediments. Anaerobic bacteria like Thermoanaerobacterium displayed a significant positive correlation with water depth. Our study reveals the presence, composition, and distribution of MPs in Bosten Lake's sediments, shedding light on their potential ecological impact.

Mechanically-Compliant Bioelectronic Interfaces through Fatigue-Resistant Conducting Polymer Hydrogel Coating.

Because of their distinct electrochemical and mechanical properties, conducting polymer hydrogels have been widely exploited as soft, wet, and conducting coatings for conventional metallic electrodes, providing mechanically compliant interfaces and mitigating foreign body responses. However, the long-term viability of these hydrogel coatings is hindered by concerns regarding fatigue crack propagation and/or delamination caused by repetitive volumetric expansion/shrinkage during long-term electrical interfacing. This study reports a general yet reliable approach to achieving a fatigue-resistant conducting polymer hydrogel coating on conventional metallic bioelectrodes by engineering nanocrystalline domains at the interface between the hydrogel and metallic substrates. It demonstrates the efficacy of this robust, biocompatible, and fatigue-resistant conducting hydrogel coating in cardiac pacing, showcasing its ability to effectively reduce the pacing threshold voltage and enhance the long-term reliability of electric stimulation. This study findings highlight the potential of its approach as a promising design and fabrication strategy for the next generation of seamless bioelectronic interfaces.

Engineering Electrodes with Robust Conducting Hydrogel Coating for Neural Recording and Modulation.

Coating conventional metallic electrodes with conducting polymers has enabled the essential characteristics required for bioelectronics, such as biocompatibility, electrical conductivity, mechanical compliance, and the capacity for structural and chemical functionalization of the bioelectrodes. However, the fragile interface between the conducting polymer and the electrode in wet physiological environment greatly limits their utility and reliability. Here, a general yet reliable strategy to seamlessly interface conventional electrodes with conducting hydrogel coatings is established, featuring tissue-like modulus, highly-desirable electrochemical properties, robust interface, and long-term reliability. Numerical modeling reveals the role of toughening mechanism, synergy of covalent anchorage of long-chain polymers, and chemical cross-linking, in improving the long-term robustness of the interface. Through in vivo implantation in freely-moving mouse models, it is shown that stable electrophysiological recording can be achieved, while the conducting hydrogel-electrode interface remains robust during the long-term low-voltage electrical stimulation. This simple yet versatile design strategy addresses the long-standing technical challenges in functional bioelectrode engineering, and opens up new avenues for the next-generation diagnostic brain-machine interfaces.

Effects of the application timing of anti-erosive agents on dentin erosion.

This in vitro study aimed to evaluate the effects of the application timing of anti-erosive agents on dentin erosion. Eighty dentin specimens with dimensions of 2 × 2 × 2 mm were prepared and randomly divided into 4 groups based on the treatment solutions: 1.23 × 104 µg/ml sodium fluoride (NaF), 120 µg/ml chlorhexidine (CHX), 300 µg/ml quercetin (QUE), and deionized water (DW, negative control). The specimens in each group were further divided into 2 subgroups according to the application timing of the treatment solutions (n = 10): before the erosive challenges (PRE) and after the erosive challenges (POST). All specimens were submitted to 4 daily erosive challenges for 5 d. For each erosive challenge, the specimens in the subgroup PRE were treated with the respective solutions for 2 min and then immersed in cola drinks for 5 min, while the specimens in the subgroup POST were immersed in cola drinks for 5 min followed by treatment with the respective solutions for 2 min. The erosive dentin loss (EDL) was measured using a contact profilometer, and the surface morphology of the dentin specimens was evaluated by scanning electron microscopy at the end of the experiment. The data were statistically analyzed using two-way analysis of variance (ANOVA) and Bonferroni's test (α = 0.05). Significantly less EDL was observed in the groups NaF, CHX, and QUE than in the group DW (all P < 0.001). Significantly lower EDL was observed in the groups CHX and QUE than in the group NaF (P = 0.001 and P < 0.001, respectively). For CHX, subgroup POST exhibited significantly less EDL than subgroup PRE (P < 0.001). Regarding QUE, subgroup PRE showed significantly less EDL than subgroup POST (P < 0.001). Furthermore, a relatively greater number of obliterated dentinal tubules was visible in the subgroup POST rather than in the subgroup PRE of the group CHX, while in the group QUE, narrower dentinal tubules were observed in the subgroup PRE than those in subgroup POST. In conclusion, CHX and QUE showed the best performance in controlling dentin erosion. CHX was more effective in reducing EDL when applied after erosive challenges, whereas QUE worked more effectively when used before erosive attacks. The application timing should be considered when evaluating the effects of anti-erosive agents because it may determine their effectiveness.

Ionic liquids-modified cellulose coated magnetic nanoparticles for enzyme immobilization: Improvement of catalytic performance.

In this work, ionic liquids-modified magnetic carboxymethyl cellulose nanoparticles (IL-MCMC) were prepared and used as supports for enzyme immobilization. The specific activity of immobilized lipase PPL-IL-MCMC was 1.43 and 2.81 folds higher than that of free PPL and PPL-MCMC, respectively. Water contact angle analysis indicated that the introduction of ionic liquids increased the hydrophobicity of supports, which in tune induced the lid-opening of lipase, allowing its active sites to become more accessible. In addition, the affinity between lipase and substrate immobilized on the prepared supports was enhanced. The same method was also applied to analyze immobilize penicillin G acylase (PGA) to further investigate the general applicability of the method. The results showed that the immobilized PGA exhibited higher stability than many other reported PGAs. The developed composites may be utilized as excellent supports for enzyme immobilization in industrial application.

Enhancement of light aromatics from catalytic fast pyrolysis of cellulose over bifunctional hierarchical HZSM-5 modified by hydrogen fluoride and nickel/hydrogen fluoride.

Pore structure and accessible active sites of HZSM-5 (Z5) are the key factors for its catalysis. The bifunctional hierarchical Z5 were prepared with leaching agent HF and loading Ni, and their performance for catalytic fast pyrolysis (CFP) of cellulose was investigated in a drop tube quartz reactor. Z5 modified with 0.5 mol/L HF (0.5F-Z5) showed excellent light aromatics (LAs) yield, which can be attributed to the enhancement in the small mesopores (2-10 nm) and the decrease of Brønsted acid sites during dealumination. Simultaneously, the loading of a 1 wt% Ni produced more LAs than 0.5F-Z5, due to the improvement in deoxidation/hydrogenation reactions. The highest LAs yield (31.3%) was obtained over 1%Ni-0.5 mol/LHF-Z5, which increased by 44.9% compared to the parent Z5. In addition, the reaction routes over different active centers and acid-catalyzed reactions were analyzed, based upon the composition of bio-oils and catalyst characterization.

[The effect of carboxymethyl chitosan zinc and peptide on IL-1,TNF-α and PGE-2 in gingival crevicular fluid of miniature pigs].

PURPOSE: This experiment was aimed at exploring whether carboxymethyl chitosan zinc and peptide （CMC-Zn(+)-P） can reduce the occurrence and development of periodontal tissue inflammation effectively by observing the change of IL-1,TNF-α and PGE-2 level in gingival crevicular fluid （GCF） before and after brushing, so as to find a new effective material in preventing and treating periodontal diseases. METHODS: Miniature pigs were selected as experimental subjects and divided into 4 groups randomly: the control group; CMC-Zn(+)-P group (material group);brushing group; brushing + CMC-Zn(+)-P group (composite group). Gingival crevicular fluid before and one month after the experiment was collected. The levels of IL-1, TNF-α and PGE-2 were examined by enzyme-linked immune-sorbent assay, while the clinical periodontal index was recorded. SPSS 18.0 software package was used for statistical analysis. RESULTS: There was no significant difference in levels of IL-1, TNF-α and PGE-2 and clinical periodontal index between the 4 groups before experiment. After one month, the levels of IL-1, TNF-α, PGE-2 in GCF had significant difference between 4 groups. The levels of IL-1, TNF-α, PGE-2 in composite group were significant lower than that of the other three groups (P<0.008).The levels of IL-1, TNF-α and PGE-2 in the material group and brushing group were significantly lower than that of the control group (P<0.008). Compared with materials group, the brushing group had significantly lower level of IL-1,significantly higher level of PGE-2 ,but no difference in the level of TNF-α.In addition, the teeth calculus index of composite group was significantly lower than that of other groups (P<0.05). CONCLUSIONS: CMC-Zn(+)-P can effectively reduce periodontal tissue inflammation and cut down the speed of deposition of dental calculus. If used cooperatively with brushing, the effect will be better.

[Caries status of the first permanent molar among 7- to 9-year-old children in Tangshan city and their correlation].

OBJECTIVE: This study aims to investigate the caries status of the first permanent molar and primary tooth among 7- to 9-year-old children in Tangshan city and the correlation between caries of primary tooth and the first permanent molar. METHODS: A stratified cluster sampling method was used on the basis of the Basic Approach of Oral Health Survey of WHO and the Guideline of the Third National Oral Health Survey. A total of 10 primary schools were randomly sampled in clusters that included 51 primary school sampling spots in Tangshan. The caries status of 1 794 children aged 7 years to 9 years was examined. RESULTS: The prevalence rate of the first permanent molar caries was 47.49% (852/1 794), the mean number of DMFT was 1.30 ± 1.59, the mean number of DMFS was 1.96 ± 3.40, and the filling rate was only 2.35% (20/852). The preva- lence rate and mean DMFT of the first permanent molar caries showed significant difference between different ages and genders (P < 0.05). However, the mean DMFS of the first permanent molar caries only showed significant difference between the various ages (P < 0.05). The prevalence rate of the primary tooth caries was 83.11% (1 491/1 794), the mean number of dmft was 4.82 ± 3.55, the mean number of dmfs was 6.51 ± 5.61, and the filling rate was 12.41% (185/1 491). Caries of primary tooth was the first permanent molar caries risk factor [r = 0.277, OR = 5.736, P = 0.00, 95% CI (4.175, 7.881)]. Significant correlation was found between the caries of primary tooth and first permanent molar (r = 0.274, P < 0.001). CONCLUSION: Caries status of the first permanent molar among 7- to 9-year-old children in Tangshan city is serious. Caries status of primary tooth may play an important role in predicting the first permanent molar caries in clinic and prevention.

Rapid repair and regeneration of damaged rabbit sciatic nerves by tissue-engineered scaffold made from nano-silver and collagen type I.

A tissue-engineered scaffold with nano-silver and collagen type I was constructed and investigated for its ability to adsorb laminin and the usefulness in the repair and regeneration of damaged peripheral nerves in animals. The nano-silver scaffold displayed ideal microtubule structure under electronic microscope; even distribution of the nano-silver particles was also seen with energy spectrometry. After immersion in a laminin solution, the laminin-attached scaffolds were implanted into rabbits to repair a 10-mm injury of the sciatic nerve. At 30 days post-implantation, regeneration of the damaged nerve was evaluated by transmission electron microscopy, electrophysiological examination and fluoro-gold (FG) retrograde labelling. Compared with the control collagen-scaffold without nano-silver, the nano-silver-containing scaffold showed a higher rate of laminin adsorption, regenerated a nerve with a thicker myelin sheath and improved the nerve conduction velocity and nerve potential amplitude. FG retrograde labelled the newly grown axons in the spinal cord cortex anterior horn and the dorsal root ganglion. These results demonstrate the superior functionality of the nano-silver-collagen scaffold in the adsorption to laminin and subsequent regeneration of damaged peripheral nerves.

[A statistic analysis on absence of third molar germs in orthodontic patients].

OBJECTIVE: To examine the absence of the third molar germs in orthodontic patients and to evaluate the relationship between third molar germs and malocclusion. METHODS: The subjects comprised 234 patients (male 92, female 142) from the orthodontic clinic whose ages were 14-18. The assessments of the third molar germs were made from panoramic radiographs, and the assessments of ANB angle were made from lateral cephalograms. All the data were analyzed by statistic chi2 test. RESULTS: The percentage of male who missed one or more third molar gems (37.0%) was higher than that of female (24.6%). There was no significant difference between the absent frequencies of third molar germs on left and right sides in either maxilla or mandible. The absent percentage of third molar germs in skeletal III subjects was higher than those in both skeletal class I and II subjects. The absent difference of third molar germs was in upper arches (P < 0.05), but not in lower arches (P > 0.05). There was no significant difference in absent percentage of third molar germs between skeletal class I and II subjects. CONCLUSION: Male patients have higher absent frequencies of third molar germs than female ones. Skeletal class III patients have higher absence of third molar germs in upper jaws than skeletal class I and II patients.