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.

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.

Engineering strategies for enhanced heterologous protein production by Saccharomyces cerevisiae.

Microbial proteins are promising substitutes for animal- and plant-based proteins. S. cerevisiae, a generally recognized as safe (GRAS) microorganism, has been frequently employed to generate heterologous proteins. However, constructing a universal yeast chassis for efficient protein production is still a challenge due to the varying properties of different proteins. With progress in synthetic biology, a multitude of molecular biology tools and metabolic engineering strategies have been employed to alleviate these issues. This review first analyses the advantages of protein production by S. cerevisiae. The most recent advances in improving heterologous protein yield are summarized and discussed in terms of protein hyperexpression systems, protein secretion engineering, glycosylation pathway engineering and systems metabolic engineering. Furthermore, the prospects for efficient and sustainable heterologous protein production by S. cerevisiae are also provided.

LMDA-Net:A lightweight multi-dimensional attention network for general EEG-based brain-computer interfaces and interpretability.

Electroencephalography (EEG)-based brain-computer interfaces (BCIs) pose a challenge for decoding due to their low spatial resolution and signal-to-noise ratio. Typically, EEG-based recognition of activities and states involves the use of prior neuroscience knowledge to generate quantitative EEG features, which may limit BCI performance. Although neural network-based methods can effectively extract features, they often encounter issues such as poor generalization across datasets, high predicting volatility, and low model interpretability. To address these limitations, we propose a novel lightweight multi-dimensional attention network, called LMDA-Net. By incorporating two novel attention modules designed specifically for EEG signals, the channel attention module and the depth attention module, LMDA-Net is able to effectively integrate features from multiple dimensions, resulting in improved classification performance across various BCI tasks. LMDA-Net was evaluated on four high-impact public datasets, including motor imagery (MI) and P300-Speller, and was compared with other representative models. The experimental results demonstrate that LMDA-Net outperforms other representative methods in terms of classification accuracy and predicting volatility, achieving the highest accuracy in all datasets within 300 training epochs. Ablation experiments further confirm the effectiveness of the channel attention module and the depth attention module. To facilitate an in-depth understanding of the features extracted by LMDA-Net, we propose class-specific neural network feature interpretability algorithms that are suitable for evoked responses and endogenous activities. By mapping the output of the specific layer of LMDA-Net to the time or spatial domain through class activation maps, the resulting feature visualizations can provide interpretable analysis and establish connections with EEG time-spatial analysis in neuroscience. In summary, LMDA-Net shows great potential as a general decoding model for various EEG tasks.

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.

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.

MtDNA Copy Number in Oral Epithelial Cells Serves as a Potential Biomarker of Mitochondrial Damage by Neonicotinoid Exposure: A Cross-Sectional Study.

As the mitochondrial DNA copy number (mtDNAcn) has been reported to be a biomarker for mtDNA damage in honeybees when exposed to sublethal neonicotinoids, the feasibility of using human mitochondria as a predictor upon neonicotinoid exposure remains elusive. This study investigated the association between the urinary neonicotinoid and the relative mtDNAcn (RmtDNAcn) of oral epithelial cells collected in a cross-sectional study with repeated measurements over 6 weeks. The molecular mechanism underlying neonicotinoid-caused mitochondrial damage was also examined by in vitro assay. Herein, the average integrated urinary neonicotinoid (IMIRPF) concentration ranged from 8.01 to 13.70 µg/L (specific gravity-adjusted) during the sampling period. Concomitantly, with an increase in the urinary IMIRPF, the RmtDNAcn significantly increased from 1.20 (low group) to 1.93 (high group), indicating potential dose-dependent mitochondrial damage. Furthermore, the linear regression analysis confirmed the significant correlation between the IMIRPF and RmtDNAcn. Results from in vitro assays demonstrated that neonicotinoid exposure led to the inhibition of the genes encoding mitochondrial oxidative phosphorylation (OXPHOS) complexes I and III (e.g., ND2, ND6, CytB, and CYC1), accompanied by increased reactive oxygen species production in SH-SY5Y cells. Conjointly, neonicotinoid exposure led to mitochondrial dysfunction and a resulting increase in the RmtDNAcn, which may serve as a plausible biomarker in humans.

Toxic effects of maternal cadmium exposure on the metabolism and transport system of amino acids in the maternal livers.

Fetal growth restriction (FGR) is one of the most common obstetric diseases, and affects approximately 10 % of all pregnancies worldwide. Maternal cadmium (Cd) exposure is one of the factors that may increase the risk of the development of FGR. However, its underlying mechanisms remain largely unknown. In this study, using Cd-treated mice as an experimental model, we analyzed the levels of some nutrients in the circulation and the fetal livers by biochemical assays; the expression patterns of several key genes involved in the nutrient uptake and transport, and the metabolic changes in the maternal livers were also examined by quantitative real-time PCR and gas chromatography-time of flight-mass spectrometry method. Our results showed that, the Cd treatment specifically reduced the levels of total amino acids in the peripheral circulation and the fetal livers. Concomitantly, Cd upregulated the expressions of three amino acid transport genes (SNAT4, SNAT7 and ASCT1) in the maternal livers. The metabolic profiling of maternal livers also revealed that, several amino acids and their derivatives were also increased in response to the Cd treatment. Further bioinformatics analysis indicated that the experimental treatment activated the metabolic pathways, including the alanine, aspartate and glutamate metabolism, valine, leucine and isoleucine biosynthesis, arginine and proline metabolism. These findings suggest that maternal Cd exposure activate the amino acid metabolism and increase the amino acid uptake in the maternal liver, which reduces the supply of amino acids to the fetus via the circulation. We suspect that this underlies the Cd-evoked FGR.

Polyhalogenated carbazoles induce hepatic metabolic disorders in mice via alteration in gut microbiota.

Polyhalogenated carbazoles (PHCZs) have been widely accepted as emerging pollutants, whereas their ecological and health risks remain uncertain. Herein, female and male Sprague-Dawley (SD) mice were treated with four typical PHCZs to investigate their negative consequences, along with alternations in gut microbiota to indicate underlying mechanisms. In female mice, the relative liver weight ratio increased after four PHCZs exposure; 2-bromocarbazole (2-BCZ) increased urine glucose level; 3-bromocarbazole (3-BCZ) decreased the glucose and total cholesterol levels; 3,6-dichlorocarbazole (3,6-DCCZ) decreased glucose level. The only disturbed biochemical index in male mice was the promoted alkaline phosphatase (ALP) level by 3,6-DCCZ. We also found that the differential blood biochemical indices were correlated with gut microbiota. 3-BCZ and 3,6-DCCZ altered Bacteroidetes and Proteobacteria phyla in female and male mice, which were correlated with metabolic disorders. Our findings demonstrated the correlation between PHCZs induced potential hepatotoxicity and metabolic disorders may be due to their dioxin-like potentials and endocrine disrupting activities, and the gender differences might result from their estrogenic activities. Overall, data presented here can help to evaluate the ecological and health risks of PHCZs and reveal the underlying mechanisms.

The influences of perfluoroalkyl substances on the rheumatoid arthritis clinic.

BACKGROUND: The effect of environmental factors on genetically susceptible individuals is a basic link in the pathogenesis of rheumatoid arthritis. Perfluoroalkyl substances (PFASs) are a class of synthetic organic fluorine chemicals, which have been mass-produced and widely used in the past 60 years, and also have been shown to be one of the major pollutants affecting human health. The impact of fluoride on the development of Rheumatoid Arthritis (RA) is unclear. This study explored the relationship between common fluoride and clinical manifestations of rheumatoid arthritis. RESULTS: A cohort of 155 patients with RA and 145 health controls in Second Affiliated Hospital of Zhejiang University School of Medicine were investigated. Serum concentrations of all fluoride detected were higher in RA patients than in healthy controls. There were 43 male patients and 112 female patients in the RA cohort. Some of perfluoroalkyl substances (perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorotrdecanoate (PFTrA), perfluorooctanesulfonate (PFOS)) were correlated negatively with the Body Mass Index (BMI); some of them (PFOA, PFNA, PFTrA, PFOS, 8:2 Chlorinated polyfluorinated ether sulfonate (8:2Cl-PFESA)) were correlated positively with the Disease Activity Score 28 (DAS28); two (PFOA, PFOS) of them were correlated positively with the white blood cell count, and one (Perfluoroundecanoate (PFUnA)) of them was correlated negatively with the hemoglobin; two (Perfluorodecanoate (PFDA), PFUnA) of them were correlated negatively with the presence of interstitial lung disease. CONCLUSION: These data suggest that exposure to perfluoroalkyl substances may promote the disease activity of rheumatoid arthritis and the visceral lesions.

Method for parallelism measurement of geometrical waveguides based on the combination of an autocollimator and a testing telescope.

Augmented reality (AR) is desperately needed in the Metaverse. The geometrical waveguide receives increased attention in AR technology as achieving high resolution, full-color display, etc. However, the stray light and ghost image problems resulting from the parallelism errors severely deteriorate the imaging quality. According to the light propagation of the waveguide, a measuring system based on the combination of the autocollimator and the testing telescope (CAT) method was proposed to measure the parallelism errors of the partially reflective mirror array (PRMA). The results indicated that this method could measure the parallelism errors precisely with the maximum repeatability of 0.63 ' ' . The method could decouple the coupling of the parallelism errors of the PRMA and the substrate surfaces to imaging quality effectively. The precise parallelism measuring is expected to contribute to mass production and low cost by promoting the waveguide design and fabrication.

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.

Molecular Dynamics Simulation on the Wettability of Nanoscale Wrinkles: High Water Adhesion of Rose Petals.

Understanding the high water adhesion of rose petals is of great significance in artificial surface design. With all-atom molecular dynamics simulation, the wettability of nanoscale wrinkles was explored and compared to that of nanoscale strips with favorable hydrophobicity. The dewetting and wetting of gaps between nanoscale structures represent the Cassie-Baxter (CB) and Wenzel (WZ) states of the macroscopic droplet deposited on the textured surface, respectively. We uncovered the intermediate state, which is different from the CB and WZ states for wrinkles. Structures and free-energy profiles of metastable and transition states under various pressures were also investigated. Moreover, free-energy barriers for the (de)wetting transitions were quantified. On this basis, the roles of pressure and the unique structures of nanoscale wrinkles in the high water adhesion of rose petals were identified.

Toxicological Effect and Molecular Mechanism of the Chiral Neonicotinoid Dinotefuran in Honeybees.

With the increasing demand for pollinating services, the wellness of honeybees has received widespread attention. Recent evidence indicated honeybee health might be posed a potential threat by widely used neonicotinoids worldwide. However, little is known about the molecular mechanism of these insecticides in honeybees especially at an enantiomeric level. In this study, we selected two species of bees, Apis mellifera (A. mellifera) and Apis cerana (A. cerana), to assess the toxicity and molecular mechanism of neonicotinoid dinotefuran and its enantiomers. The results showed that S-dinotefuran was more toxic than rac-dinotefuran and R-dinotefuran to honeybees by oral and contact exposures as much as 114 times. A. cerana was more susceptible to highly toxic enantiomer S-dinotefuran. S-dinotefuran induced the immune system response in A. cerana after 48 h exposure and significant changes were observed in the neuronal signaling of A. mellifera under three forms of dinotefuran exposure. Moreover, molecular docking also revealed that S-dinotefuran formed more hydrogen bonds than R-dinotefuran with nicotinic acetylcholine receptor, indicating the higher toxicity of S-dinotefuran. Data provided here show that R-dinotefuran may be a safer alternative to control pests and protect pollinators than rac-dinotefuran.

Antibiotic treatments to mothers during the perinatal period leaving hidden trouble on infants.

Antibiotic application during the perinatal period is unavoidable in the clinic, but the potential effects on mothers and infants remain unknown. Herein, 25 breast milk samples from mothers who received cefuroxime (CXM) or CXM + cefoxitin (CFX) treatments and fecal samples from their infants were collected to investigate the undesirable effects of antibiotics on the microbiota of mothers and neonates. Furthermore, five fecal samples of infants, whose mothers had antibiotic treatments, were collected at a 6-month postpartum follow-up visit to evaluate the long-term effects on infants' gut microbiota. Moreover, the relative abundance of antibiotic resistance genes (ARGs) in fecal samples was compared to investigate the transfer of ARGs in the infant gut microbiota. The results indicated that the antibiotic treatments had no influence on the microbiota of breast milk. The dominant bacterial phyla in the fecal samples changed to Firmicutes and Proteobacteria after antibiotic treatments, while the bacterial community showed a recuperative trend at the follow-up visits. In addition, the abundance of ARGs in the infant gut microbiota demonstrated a declining trend in the CXM- and CXM + CFX-treated groups, while ARG abundance presented a significant increasing trend after a 6-month recovery period. CONCLUSION: Antibiotic treatments for mothers during the perinatal period disturb the gut microbiota in neonates. The infants' gut microbiota would partly return to their initial state after rehabilitation, but the transfer of ARGs would leave the hidden trouble of antibiotic resistance. Overall, the data presented here can help to guide the scientific use of antibiotics during the perinatal period and provide potential approaches to mitigate the negative consequences. WHAT IS KNOWN: • Antibiotic application during the perinatal period is unavoidable in the clinic. • Misuse of antibiotics can cause various unintended consequences, especially for antibiotic resistance. WHAT IS NEW: • Antibiotic treatments had no influence on the microbiota of breast milk but greatly disturbed the gut microbiota composition in infants. • The gut microbiota in infants would partly return to its initial state after rehabilitation but the transfer of ARGs would leave the hidden trouble of antibiotic resistance.

High-precision and long-range measurement of micro-gear starting torque.

The ability to measure micro-starting torque is pivotal for micromechanical equipment, which has wide usage in mechanical manufacturing, electrical, electronic, and other industries. However, the measurement range of existing methods is about N⋅m or mN⋅m. There is not much research on the measurement of micro-torque starting in the µN⋅m. In this paper, a novel micro-gear starting torque measurement system, to the best of our knowledge, is proposed based on an optical lever with a long range from 1 to 10µN⋅m. The system device consists of the optical lever, cantilever, and position sensitive device. A micro-gear was used to assess the performance of the proposed method. The standard deviation of the measured starting torque is 1.2µN⋅m. The external factors that can contribute to the uncertainty of the measurement system, such as force measurement, arm of force, and repeatability, have been analyzed and quantified. The relative combined uncertainty is estimated at 3.0%, approximately.

Development of a nanoscale displacement sensor based on the shadow method.

A novel, to the best of our knowledge, bionic coaxial micro-displacement sensor based on the shadow method is developed and experimentally demonstrated inspired by the water strider walking on the water. The water is used as the sensitive element to measure the micro- displacement. A meniscus is formed by the superhydrophobic circular plate subjected to a coaxial displacement excitation. Then a shadow is formed because of the refraction when the parallel light illuminates the meniscus. A maximum coaxial displacement sensitivity of 62 nm/pixel over the displacement range of 50 µm is achieved experimentally. The linearity error in the measurement range was 1.58%. Therefore, it is expected that this displacement sensor can be used in many important ultraprecision measurement fields because of the advantages of the easy structure and high resolution.

Enantioselective neurotoxicity and oxidative stress effects of paclobutrazol in zebrafish (Danio rerio).

Paclobutrazol is a widely used chiral plant growth regulator and its enantioselective toxicity in aquatic organisms is less explored till now. Herein, the enantioselective neurotoxicity of paclobutrazol mediated by oxidative stress in zebrafish were investigated. The oxidative stress parameters and neurotoxic biomarkers changed significantly in each exposure group, and paclobutrazol showed enantioselective toxicity in zebrafish. Firstly, (2R, 3R)-paclobutrazol exhibited a stronger oxidative stress in zebrafish than (2S, 3S)-enantiomer (P < 0.05). Then, activities of acetylcholinesterase, calcineurin, and total nitric oxide synthase in (2R, 3R)-paclobutrazol treatments were 0.61-0.89, 1.24-1.53, and 1.21-1.35-fold stronger (P < 0.05) than those in (2S, 3S)-enantiomer treatments, respectively. Next, the content variations of four neurotransmitters in zebrafish exposed to (2R, 3R)-paclobutrazol were significantly larger than those in (2S, 3S)-enantiomer treatments (P < 0.05). Moreover, (2R, 3R)-paclobutrazol had stronger binding with the receptors than (2S, 3S)-enantiomer through molecular docking. The integrated biomarker response values further demonstrated that (2R, 3R)-paclobutrazol showed stronger toxicity to zebrafish than (2S, 3S)-enantiomer. Furthermore, the neurotoxicity of paclobutrazol can be interpreted as the mediating effect of oxidative stress in zebrafish through correlation analysis, and an adverse outcome pathway for the nervous system in zebrafish induced by paclobutrazol was proposed. This work will greatly extend our understanding on the enantioselective toxic effects of paclobutrazol in aquatic organisms.

Effects of Bisphenol A and Bisphenol S Exposure at Low Doses on the Metabolome of Adolescent Male Sprague-Dawley Rats.

Toxic effects induced upon exposure to low-dose bisphenol A (BPA) or bisphenol S (BPS) remains controversial. In this study, metabolomics was used to examine the metabolomic perturbation arising from 28 days of exposure to BPA or BPS at 50 µg/kg bw/day in Sprague-Dawley (SD) rats. Endogenous metabolite profiling revealed a clear discrimination of metabolome in the rat plasma among BPA-treatment, BPS-treatment, and control groups. BPA exposure induced the up-regulation of 19 metabolites and down-regulation of 32 metabolites in plasma of SD rats, compared with the control. BPS exposure induced the up-regulation of 15 metabolites and the down-regulation of 33 metabolites in the plasma of SD rats, compared with the control. Joint pathway analysis suggested marked perturbations in the citrate cycle, butanoate metabolism, and alanine, aspartate, and glutamate metabolism for BPA-exposed rats as well as glycerophospholipid metabolism for BPS-exposed rats. These findings provide novel insights into associations between the metabolomic perturbation and phenotypic changes arising from BPA and BPS exposure.

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.