Measurement Methods for Droplet Adhesion Characteristics and Micrometer-Scale Quantification of Contact Angle on Superhydrophobic Surfaces: Challenges and Opportunities.

Inspired by nature, superhydrophobic surfaces have been widely studied. Usually the wettability of a superhydrophobic surface is quantified by the macroscopic contact angle. However, this method has various limitations, especially for precision micro devices with superhydrophobic surfaces, such as biomimetic artificial compound eyes and biomimetic water strider robots. These precision micro devices with superhydrophobic surfaces proposed a higher demand for the quantification of contact angles, requiring contact angle quantification technology to have micrometer-scale measurement capabilities. In this review, it is proposed to achieve micrometer-scale quantification of superhydrophobic surface contact angles through droplet adhesion characteristics (adhesion force and contact radius). Existing contact angle quantification techniques and droplet characteristics' measurement methods were described in detail. The advancement of micrometer-scale quantification technology for the contact angle of superhydrophobic surfaces will enhance our understanding of superhydrophobic surfaces.

Breastfeeding Barriers for Preterm Infants in Neonatal Intensive Care Unit Environments: A Systematic Assessment and Meta-Analysis.

Background: Breast milk is vital for the growth and development of preterm infants. However, in Neonatal Intensive Care Units (NICUs), mothers often encounter significant challenges in breastfeeding. Objective: This study aims to systematically evaluate the barriers to breastfeeding in NICUs, thereby providing evidence-based support for clinical practices. Methods: A comprehensive search was conducted in the Cochrane Library, PubMed, Web of Science, Embase, and Scopus databases, up to September 2023. Meta-analysis was performed using Stata 15.0, applying fixed or random effects models to calculate odds ratios (OR) and their 95% confidence intervals (CI). Study quality was assessed using the Newcastle-Ottawa Scale for cases and cohorts and the Agency for Healthcare Research and Quality standards for cross-sectional studies. Heterogeneity was evaluated using Cochran's chi-squared test (Cochran's Q) and I2 statistics, and publication bias was assessed through funnel plots and symmetry tests. Results: A total of 32 studies were included, encompassing 96,053 preterm infants. The main barriers to breastfeeding in preterm infants included: low gestational age (OR = 1.36, 95% CI: 1.06-1.75), lower maternal education (OR = 1.64, 95% CI: 1.39-1.93), insufficient breast milk (OR = 2.09, 95% CI: 1.39-1.93), multiple births (OR = 1.615, 95% CI: 1.18-2.210), smoking (OR = 2.906, 95% CI: 2.239-3.771), and single motherhood (OR = 1.439, 95% CI: 1.251-1.654). Conclusion: This study underscores the need for individualized breastfeeding support strategies in NICUs, taking into account the diverse backgrounds of mothers. Future research should focus on unraveling the underlying mechanisms affecting breastfeeding in preterm infants, with the goal of enhancing breastfeeding rates and improving developmental outcomes.

Effect of breast milk intake volume on early behavioral neurodevelopment of extremely preterm infants.

BACKGROUND: This study aimed to explore the effects of breast milk feeding volume on the early behavioral neurodevelopment of extremely preterm infants (gestational age < 28 weeks). METHODS: The study was conducted from 1 January 2021 to 31 March 2023. A total of 187 preterm infants from a neonatal intensive care unit (NICU) in a Grade III Class A hospital in Zhejiang, China, were divided based on the proportion of breast milk in their total enteral nutrition: high proportion (≥ 80%, including exclusive breast milk feeding), medium proportion (20% ~ < 80%), and low proportion (< 20%). The study investigated motor performance and behavioral neurodevelopment at 37 weeks of corrected gestational age, as well as the total incidence of intracranial hemorrhage within the first four weeks postpartum. RESULTS: The low breast milk feeding group had significantly lower scores in infant motor performance (31.34 ± 5.85) and elicited item scores (19.89 ± 5.55) compared to the medium and high groups (33.52 ± 4.33, 22.13 ± 4.22; and 35.86 ± 5.27, 23.91 ± 4.98), p < 0.05, respectively. Despite no significant difference in behavioral ability, the low proportion group exhibited lower passive muscle tension and primitive reflex scores than the medium and high proportion groups. The high proportion group showed higher active muscle tension scores. Ultrasound results revealed varying incidences of intracranial hemorrhage: 72.9% in low, 52.5% in medium, and 19.6% in the high proportion groups. CONCLUSIONS: Medium to high levels of breast milk feeding contribute positively to motor and behavioral neurological development in extremely preterm infants and decrease the likelihood of ventricular hemorrhage. However, it does not have a significant effect on the development of behavioral abilities. Due to the limited sample size, the next step will be to expand the sample size and further investigate the extent of the impact on various aspects of the nervous system.

Exploration of Sweeping Effect: Droplet Coalescence Jumping of a Rolling and Static Droplet.

The sweeping effect of merged droplets plays a key role in enhancing application performance due to the continuing coalescence caused by the horizontal jumping velocity. Most studies focused on static droplet coalescence jumping, while moving droplet coalescence is poorly understood. In this work, we experimentally and numerically study the coalescence of a rolling droplet and a static one. When the droplet radius ratio is larger than 0.8, as the dimensionless initial velocity increases and the vertical jumping velocity first decreases and then increases. The critical dimensionless initial velocity Vc* corresponding to the minimum vertical jumping velocity could be estimated as 0.9(rs2rm2). When the droplet radius ratio is smaller than 0.8, the dimensionless initial velocity has a positive effect on the vertical jumping velocity. The mechanism of the vertical jumping velocity can be attributed to two parts: liquid bridge impact and retraction of the merged droplet. The squeezing effect generated by the initial velocity between the two droplets promotes the growth of the liquid bridge and enhances the impact effect of the liquid bridge but weakens the upward velocity accumulation caused by the retraction of the merged droplets. However, different from the vertical jumping velocity, the horizontal jumping velocity is approximately proportional to the dimensionless initial velocity. The outcome of our work elucidates a fundamental understanding of a rolling droplet coalescing with a static one.

Exploring the Effects of Liquid Marbles' Deformation on Their Rolling Resistance.

Liquid marbles (LMs) are nonwetting droplets manufactured by encapsulating droplets with micro- or nanoscale particles. These marbles are widely used as transport carriers for digital microfluidics due to their rapid displacement velocity and leak-free transport. An improved understanding of the resistance mechanism of rolling LMs is crucial for their transport and manipulation. In this study, we investigated the rolling resistance of LMs obtained with different powders and volumes using a high-speed camera. Our findings suggest that the deformation of liquid marbles would hinder their rolling by a resistance torque. To depict this resistance effect, we propose a theoretical model (f∼λ(ε-12Bo1/2ε2+14Boε3)), where f is the rolling resistance of marbles, λ is the deflection coefficient, Bo is the Bond number, and (ε is the contact surface deformation) that accurately predicts the relationship between deformation and rolling resistance, which is supported by our experimental results. To further validate our theoretical model, we conducted three independent experiments: shape detection of prepared LMs, measuring the elastic force of LMs, and detecting the diffusive motion of the encapsulating particles. Furthermore, we discuss three factors that affect the rolling resistance: the volume of the marbles, the type and size of the encapsulating particles, and the substrate roughness. This comprehensive study not only generalizes the mechanism of deformation hindering the rolling of liquid marbles but also provides a theoretical framework to predict the relationship between the deformation and rolling resistance. These findings have practical implications for improving the manipulation efficiency and advancing the use of LMs as microfluidic carriers.

Effect of Breast Milk on the Frequency of Bronchopulmonary Dysplasia in Very Low Birth Weight Premature Infants: A Meta-analysis.

Purpose: To analyze the effect of different feeding types on bronchopulmonary dysplasia (BPD) in very low birth weight preterm infants. Methods: The Cochrane Library, PubMed, Embase, China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform, China Biomedical Literature Database (CBM) were searched for literature related to breastfeeding and BPD, with a search period from their inception to January 2023. Two researchers independently screened the literature, extracted data, and assessed the quality of included studies before analyzing the data using Stata16 and RevMan5.4.1 software. Results: A total of 17 studies were included. The results showed that there was no significant difference in the frequency of BPD between human milk (HM) and donor human milk (DHM) (OR = 0.54, 95% CI: 0.29-1.03, p = 0.07). However, DHM had a significant effect in reducing the frequency of BPD compared to preterm formula (PF) (OR = 0.62, 95% CI: 0.41-0.94, p = 0.02). Exclusive HM also had a significant effect in reducing the frequency of BPD compared to exclusive PF (OR = 0.51, 95% CI: 0.34-0.78, p = 0.002), as well as compared to any PF (OR = 0.57, 95% CI: 0.37-0.88, p = 0.01). Furthermore, mainly (>50%) HM had a significant effect in reducing the frequency of BPD compared to mainly PF (OR = 0.72, 95% CI: 0.55-0.93, p = 0.01). However, there was no statistically significant difference between any HM and exclusive PF (OR = 0.88, 95% CI: 0.62-1.23, p = 0.46). Conclusions: Our study findings suggest that both HM and DHM have a significant protective effect in reducing the frequency of BPD occurrence compared to PF. Furthermore, even when the amount of HM is insufficient, feeding more than 50% of the HM volume still provides a protective effect against the frequency of BPD. Therefore, we recommend feeding infants with more than 50% of HM to harness the protective effect of HM against BPD occurrence.

USP22 knockdown protects against cerebral ischemia/reperfusion injury via destabilizing PTEN protein and activating the mTOR/TFEB pathway.

Ubiquitin-specific protease 22 (USP22) expression was reported to be increased in response to ischemic brain damage, but the biological role and underlying mechanism remain little understood. USP22 shRNA was intravenously injected into the mouse brain, and then a middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model was constructed, and the infarct volume, neurobehavioral deficit score, cell apoptosis, oxidative stress, and autophagy in vivo were evaluated. Oxygen-glucose deprivation/reperfusion (OGD/R) treated pheochromocytoma-12 (PC12) cells were used as an in vitro model of ischemia/reperfusion. The effects of USP22 on proliferation, apoptosis, oxidative stress, and autophagy were explored by CCK-8, flow cytometry, ELISA, and Western blot assays. The relationship between USP22 and the phosphatase and tensin homolog (PTEN) was measured by Co-IP and Western blot assays. Both USP22 and PTEN were highly expressed in MCAO/R mouse brain tissues and OGD/R-induced PC12 cells. In vitro, USP22 knockdown strongly improved OGD/R-mediated changes in cell viability, apoptosis, oxidative stress, and lactate dehydrogenase (LDH) production in PC12 cells. USP22 bound to PTEN and stabilized PTEN expression by decreasing its ubiquitination. PTEN overexpression reversed the promoting effect of USP22 knockdown on cell viability and the inhibitory effects of USP22 knockdown on apoptosis, oxidative stress, and LDH release rate in PC12 cells subjected to OGD/R. PTEN silencing elevated the protein levels of p62, p-mTOR, TFEB, and LAMP1 and reduced the protein levels of LC3-II/LC3-I. USP22 expression levels were negatively correlated with mTOR expression levels, and USP22-shRNA-mediated expression of p62, p-mTOR, TFEB, and LAMP1 was reversed by rapamycin, an inhibitor of mTOR. In vivo, USP22 silencing significantly alleviated infarct volume, neurobehavioral impairments, cell apoptosis, oxidative stress, and autophagy in MCAO/R mice. USP22 knockdown exerts neuroprotective effects in cerebral ischemia/reperfusion injury by downregulating PTEN and activating the mTOR/TFEB pathway.

Measuring the Adhesion Force and the Spreading Radius between Droplets and a Solid Surface during Short-Time Spreading.

When a droplet contacts a solid surface, the liquid spreads over the solid surface to minimize the total surface energy. This phenomenon is widespread in industrial production and nature, so research on droplet spreading is of great significance. Here, the adhesion force and the spreading radius during droplet spreading can be quantified using a highly sensitive photoelectric method. It is possible to study droplet spreading from two dimensions at the microscale. The adhesion force is measured by an optical lever, and the spreading radius is measured by an ultrafast electrical method. The measurement method allows the force resolution and the space-time resolution to reach the nanonewton lever and the nanosecond lever, respectively. We obtain the maximum spreading radius and the maximum adhesion force during short-time spreading through our technique. Moreover, we numerically simulate the droplet spreading process through the lattice Boltzmann solver and confirm the observed results. This study provides a new experimental technique for studying droplet spreading dynamics from multiple perspectives, which can deepen our understanding of droplet spreading and provide guidance for the development of new techniques.

Gli2-induced lncRNA Peg13 alleviates cerebral ischemia-reperfusion injury by suppressing Yy1 transcription in a PRC2 complex-dependent manner.

Endothelial cell dysfunction plays an important role in cerebral ischemia-reperfusion (I/R) injury. LncRNA Peg13 is reported to be down-regulated in brain microvascular endothelial cells (BMVECs) induced by glucose-oxygen deprivation (OGD), but the mechanism of its involvement in I/R progression remains to be further explored. Here, mouse BMVECs (bEnd.3 cells) were treated with OGD / reoxygenation (OGD/R) to simulate I/R injury in vitro. Peg13 and Gli2 expression was decreased in OGD/R-treated bEnd.3 cells. And overexpression of Peg13 or Gli2 prevented OGD/R-induced reduction in cell migration and angiogenesis, as well as upregulation in cell apoptosis and oxidative stress levels. Mechanism exploration showed that Gli2 promoted the transcription of Peg13. And Peg13 repressed Yy1 transcription by binding to Ezh2 (a key subunit of PRC2 complex) and inducing the enrichment of H3K27me3 in Yy1 promoter region, thereby suppressing the transcriptional inhibition effect of Yy1 on Notch3 and promoting the expression of Notch3. Consistently, Notch3 overexpression hindered OGD/R-induced endothelium dysfunction. In addition, a brain I/R injury model was established using middle cerebral artery occlusion surgery. And lentivirus-mediated Gli2 and Peg13 overexpression vectors were injected into mice via the lateral ventricle one week before surgery. The results showed that overexpression of Peg13 or Gli2 alleviated I/R-induced neurological deficit, cerebral infarct and cerebral edema. And simultaneous overexpression of Peg13 and Gli2 showed a better protective effect than overexpression of Gli2 or Peg13 alone. In conclusion, Peg13 regulated by Gli2 inhibits Yy1 transcription in a PCR2 complex-dependent manner, and blocks the transcriptional repression of Notch3 by Yy1, thereby exerting neuroprotective effects on cerebral I/R injury.

Liquid marbles, floating droplets: preparations, properties, operations and applications.

Liquid marbles (LMs) are non-wettable droplets formed with a coating of hydrophobic particles. They can move easily across either solid or liquid surfaces since the hydrophobic particles protect the internal liquid from contacting the substrate. In recent years, mainly due to their simple preparation, abundant materials, non-wetting/non-adhesive properties, elasticities and stabilities, LMs have been applied in many fields such as microfluidics, sensors and biological incubators. In this review, the recent advances in the preparation, physical properties and applications of liquid marbles, especially operations and floating abilities, are summarized. Moreover, the challenges to achieve uniformity, slow volatilization and stronger stability are pointed out. Various applications generated by LMs' structural characteristics are also expected.

Laplace Pressure Difference Enhances Droplet Coalescence Jumping on Superhydrophobic Structures.

Coalescence-induced droplet jumping has great prospects in many applications. Nevertheless, the applications are vastly limited by a low jumping velocity. Conventional methods to enhance the droplet coalescence jumping velocity are enabled by protruding structures with superhydrophobic surfaces. However, the jumping velocity improvement is limited by the height of protruding structures. Here, we present rationally designed limitation structures with superhydrophobic surfaces to achieve a dimensionless jumping velocity, Vj* ≈ 0.64. The mechanism of enhancing the jumping velocity is demonstrated through the study of numerical simulations and geometric parameters of limitation structures, providing guidelines for optimized structures. Experimental and numerical results indicate that the mechanism consists of the combined action of the velocity vectors' redirection and the Laplace pressure difference within deformed droplets trapped in limitation structures. On the basis of previous research on the mechanisms of protruding structures and our study, we successfully exploited those mechanisms to further improve the jumping velocity by combining the limitation structure with the protruding structure. Experimentally, we attained a dimensionless jumping velocity of Vj* ≈ 0.74 with an energy conversion efficiency of η ≈ 48%, breaking the jumping velocity limit. This work not only demonstrates a new mechanism for achieving a high jumping velocity and energy conversion efficiency but also sheds lights on the effect of limitation structures on coalescence hydrodynamics and elucidates a method to further enhance the jumping velocity based on protruding structures.

TDAG51-Deficiency Podocytes are Protected from High-Glucose-Induced Damage Through Nrf2 Activation via the AKT-GSK-3ß Pathway.

T cell death-associated gene 51 (TDAG51) has been implicated in the development of various pathological conditions. However, whether TDAG51 plays a role in diabetic renal disease remains unknown. The current work investigated the possible function of TDAG51 in diabetic renal disease using high-glucose (HG)-stimulated podocytes in vitro. The elevation of TDAG51 was observed in podocytes in response to HG exposure and the glomeruli of diabetic mice. The siRNAs targeting TDAG51 were applied to deplete TDAG51 in HG-stimulated podocytes. Crucially, TDAG51 deficiency was sufficient to decrease the apoptosis, oxidative stress, and inflammation caused by HG. Mechanically, the inhibition of TDAG51 was capable of enhancing the activation of nuclear factor E2-related factor 2 (Nrf2) associated with the upregulation of AKT-glycogen synthase kinase-3ß (GSK-3ß) pathway. The reduction of AKT abolished the activation of Nrf2 elicited by TDAG51 deficiency. Additionally, the reduction of Nrf2 diminished the anti-HG injury effect elicited by TDAG51 deficiency. Overall, these data demonstrate that TDAG51 deficiency defends against HG-induced podocyte damage through Nrf2 activation by regulating AKT-GSK-3ß pathway. This study suggests that TDAG1 may have a potential role in diabetic renal disease by affecting HG-induced podocyte damage.

Enhancement and Guidance of Coalescence-Induced Jumping of Droplets on Superhydrophobic Surfaces with a U-Groove.

Coalescence-induced droplet jumping has received considerable attention owing to its potential to enhance performance in various applications. However, the energy conversion efficiency of droplet coalescence jumping is very low and the jumping direction is uncontrollable, which vastly limits the application of droplet coalescence jumping. In this work, we used superhydrophobic surfaces with a U-groove to experimentally achieve a high dimensionless jumping velocity Vj* ≈ 0.70, with an energy conversion efficiency η ≈ 43%, about a 900% increase in energy conversion efficiency compared to droplet coalescence jumping on flat superhydrophobic surfaces. Numerical simulation and experimental data indicated that a higher jumping velocity arises from the redirection of in-plane velocity vectors to out-of-plane velocity vectors, which is a joint effect resulting from the redirection of velocity vectors in the coalescence direction and the redirection of velocity vectors of the liquid bridge by limiting maximum deformation of the liquid bridge. Furthermore, the jumping direction of merged droplets could be easily controlled ranging from 17 to 90° by adjusting the opening direction of the U-groove, with a jumping velocity Vj* ≥ 0.70. When the opening direction is 60°, the jumping direction shows a deviation as low as 17° from the horizontal surface with a jumping velocity Vj* ≈ 0.73 and corresponding energy conversion efficiency η ≈ 46%. This work not only improves jumping velocity and energy conversion efficiency but also demonstrates the effect of the U-groove on coalescence dynamics and demonstrates a method to further control the droplet jumping direction for enhanced performance in applications.

Coalescence-Induced Droplet Jumping.

When two or more droplets coalesce on a superhydrophobic surface, the merged droplet can jump spontaneously from the surface without requiring any external energy. This phenomenon is defined as coalescence-induced droplet jumping and has received significant attention due to its potential applications in a variety of self-cleaning, anti-icing, antifrosting, and condensation heat-transfer enhancement uses. This article reviews the research and applications of coalescence-induced droplet jumping behavior in recent years, including the influence of droplet parameters on coalescence-induced droplet jumping, such as the droplet size, number, and initial velocity, to name a few. The main structure types and influence mechanism of the superhydrophobic substrates for coalescence-induced droplet jumping are described, and the potential application areas of coalescence-induced droplet jumping are summarized and forecasted.

Exosomes Released from Rabies Virus-Infected Cells May be Involved in the Infection Process.

Exosomes are cell-derived vesicles that are secreted by many eukaryotic cells. It has recently attracted attention as vehicles of intercellular communication. Virus-infected cells release exosomes, which contain viral proteins, RNA, and pathogenic molecules. However, the role of exosomes in virus infection process remains unclear and needs to be further investigated. In this study, we aimed to evaluate the effects of exosomes on rabies virus infection. OptiPrep™ density gradient centrifugation was used to isolate exosomes from rabies virus-infected cell culture supernatants. A rabies virus G protein enzyme-linked immunosorbent assay and acetylcholinesterase activity assays were performed to verify the centrifugation fractions. Exosomes were then characterized using transmission electron microscopy and Western blotting. Our results showed that rabies virus infection increased the release of exosomes. Treatment with GW4869 and si-Rab27a, two exosomal secretion inhibitors, inhibited exosome release. Furthermore, the inhibitors reduced the levels of extracellular and intracellular viral RNA. These data indicated that exosomes may participate in the viral infection process. Moreover, our results establish a basis for future research into the roles of exosomes in rabies virus infection and as potential targets for developing new antiviral strategies.

Characterization of human enterovirus71 virus-like particles used for vaccine antigens.

Human enterovirus 71 (EV71) is a major causative pathogen of hand, foot and mouth disease (HFMD) and has caused outbreaks with significant mortality among young children in the Asia-Pacific region in recent years. Towards developing a vaccine for this disease, we have expressed and purified EV71 virus-like particles (VLPs), which resemble the authentic virus in appearance, capsid structure and protein sequence, from insect cells (Sf9) using a multistep chromatography process. We demonstrated intracellular localization of the VLPs in host cells by in situ immunogold detection, electron microscopy and immunofluorescence. Characteristics of these EV71 VLPs were studied using a variety of immunological and physicochemical techniques, which aimed to reveal that the purified EV71 VLPs have good morphology and structure consistent with natural EV71 empty capsids. Results of the amino acid analysis, SDS-PAGE, Western blotting and high-performance liquid chromatography confirmed the high purity of the EV71 VLPs. However the sedimentation coefficient of the VLPs showed that they were smaller than that of secreted EV71 VLPs purified by discontinuous cesium chloride density gradients, they were similar to the empty capsids of natural EV71 virions reported previously. Combined with the previous study that EV71 VLPs purified by a multistep chromatography process were able to elicit strong humoral immune responses in mice, our results further supported the conclusion that our EV71 VLPs had well-preserved molecular and structural characteristics. The EV71 VLPs produced from the baculovirus expression system and purified by a multistep chromatography process displayed key structural and immunological features, which would contribute to their efficacy as a HFMD vaccine.