An Environmentally Stable, Biocompatible, and Multilayered Wound Dressing Film with Reversible and Strong Adhesion.

Reversible adhesives for wound care improve patient experiences by permitting reuse and minimizing further tissue injury. Existing reversible bandages are vulnerable to water and can undergo unwanted deformation during removal and readdressing procedures. Here, a biocompatible, multilayered, reversible wound dressing film that conforms to skin and is waterproof is designed. The inner layer is capable of instant adhesion to various substrates upon activation of the dynamic boronic ester bonds by water; intermediate hydrogel layer and outer silicone backing layer can enhance the dressing's elasticity and load distribution for adhesion, and the silicone outer layer protects the dressing from exposure to water. The adhesive layer is found to be biocompatible with mouse skin. Skin injuries on the mouse skin heal more rapidly with the film compared to no dressing controls. Evaluations of the film on skin of freshly euthanized minipigs corroborate the findings in the mouse model. The film remains attached to skins without delamination despite subjecting to various degrees of deformation. Exposure to water softens the film to allow removal from the skin without pulling any hair off. The multilayered design considers soft mechanics in each layer and will offer new insights to improve wound dressing performance and patient comfort.

A sleep staging model on wavelet-based adaptive spectrogram reconstruction and light weight CNN.

Effective methods for automatic sleep staging are important for diagnosis and treatment of sleep disorders. EEG has weak signal properties and complex frequency components during the transition of sleep stages. Wavelet-based adaptive spectrogram reconstruction (WASR) by seed growth is utilized to capture dominant time-frequency patterns of sleep EEG. We introduced variant energy from Teager operator in WASR to capture hidden dynamic patterns of EEG, which produced additional spectrograms. These spectrograms enabled a light weight CNN to detect and extract finer details of different sleep stages, which improved the feature representation of EEG. With specially designed depthwise separable convolution, the light weight CNN achieved more robust sleep stage classification. Experimental results on Sleep-EDF 20 dataset showed that our proposed model yielded overall accuracy of 87.6%, F1-score of 82.1%, and Cohen kappa of 0.83, which is competitive compared with baselines with reduced computation cost.

Phytoplankton community structure and environmental factors during the outbreak of Crown-of-Thorns Starfish in Xisha Islands, South China Sea.

The "larval starvation hypothesis" proposed that the growing frequency of Crown-of-Thorns Starfish (CoTS) outbreaks could be attributed to increased availability of phytoplankton. However, comprehensive field investigation on the living environment of CoTS larvae and the availability of phytoplankton are still lacking. A cruise was conducted in June 2022 in Xisha Islands, South China Sea, to study the interaction between environmental conditions and phytoplankton communities during CoTS outbreak period. The average concentrations of dissolved inorganic phosphorus (0.05 ± 0.01 µmol L-1), dissolved inorganic nitrogen (0.66 ± 0.8 µmol L-1) and chlorophyll a (0.05 ± 0.05 µg L-1) suggested that phytoplankton may be limited for CoTS larvae in Xisha Islands. Microscopic observation and high-throughput sequencing were used to study the composition and structure of the phytoplankton communities. Bacillariophyta predominated in phytoplankton communities with the highest abundance and species richness. 29 dominant species, including 4 species with size-range preferred by CoTS larvae, were identified in Xisha Islands. The diversity index of all stations indicated a species-rich and structure-stable phytoplankton community in Xisha Islands during the period of CoTS outbreak, which may contribute to CoTS outbreak. These findings revealed the structure of phytoplankton community and environmental factors in the study area during CoTS outbreak, providing the groundwork for future research into the causes and processes of CoTS outbreak.

Mitochondria Targeted Nanoparticles Potentiate Tumor Chemo-Phototherapy by Toxic Oxidative Stress Mediated Oxeiptosis.

Insufficient accumulation of drug at the tumor site and the low drug response are the main reason for the unsatisfactory effect of cancer therapy. Delivery drugs exquisitely to subcellular level can be employed to reduce side effects, and expand the therapeutic window. Herein, a triphenylphosphine (TPP) modified lipid nanoparticles is designed which are loaded with the photosensitizer indocyanine green (ICG) and chemotherapeutic paclitaxel (PTX) for mitochondria-targeted chemo-phototherapy. Owing to the movement of majority mitochondria along microtubules in cytoplasm, mitochondrial targeting may enable PTX to act more effectively. Meanwhile, the existence of chemo-drug potentiates the phototherapy to achieve synergistic anti-tumor activity. As expected, mitochondria targeting nanomedicine (M-ICG-PTX NPs) showed improved mitochondria targeted cellular distribution and enhanced cell cytotoxicity in vitro. Also, M-ICG-PTX NPs exhibited higher tumor growth inhibition ability by promoting cell apoptosis and oxeiptosis pathway, and high effective inhibition of primary tumor growth and tumor metastasis. Taken together, M-ICG-PTX NPs may be promising nanoplatforms to achieve potent therapeutic effect for the combination of chemo- and photo-therapy (PTT).

Long-term changes in Noctiluca scintillans blooms along the Chinese coast from 1933 to 2020.

Noctiluca scintillans is one of the most common harmful algal species and widely known due to its bioluminescence. In this study, the spatial distribution, seasonal variations, and long-term trends of N. scintillans blooms in China and the related drivers were analyzed and discussed. From 1933 to 2020, a total of 265 events of N. scintillans blooms were recorded in Chinese coastal waters, with a total duration of 1052 days. The first N. scintillans bloom occurred in Zhejiang in 1933, and only three events were recorded before 1980. From 1981 to 2020, N. scintillans caused harmful algal blooms (HABs) almost every year, both the average duration and the proportion of multiphase HABs showed an increasing trend. 1986-1992, 2002-2004, and 2009-2016 were the three peak periods with a frequency of no less than five events of N. scintillans blooms per year. In terms of spatial distribution, N. scintillans blooms spread from the Southeast China Sea to the Bohai Sea after 2000, Guangdong, Fujian, and Hebei were the three provinces with the highest numbers of recorded events of N. scintillans blooms. Moreover, 86.8% of the events of N. scintillans blooms occurred in spring (March, April, and May) and summer (June, July, and August). Among environmental factors, the dissolved inorganic phosphate, dissolved silicate and chemical oxygen demand were significantly correlated with the cell density of N. scintillans during N. scintillans blooms, and most of N. scintillans blooms were recorded in the temperature range of 18.0-25.0°C. Precipitation, hydrodynamics, water temperature, and food availability might be the main factors affecting the spatial-temporal distribution of N. scintillans blooms along the Chinese coast.

Bone marrow mesenchymal stem cell-derived extracellular vesicles facilitate endometrial injury repair by carrying the E3 ubiquitin ligase WWP1.

Bone marrow mesenchymal stem cells-derived extracellular vesicles (BMSC-EVs) relieve endometrial injury. This study aimed to elucidate the BMSC-EV mechanism in alleviating endometrial injury. Endometrial injury model in vivo was induced using 95% ethanol, and endometrial epithelial cells (EECs) treated with mifepristone were applied as an endometrial injury model in vitro. After BMSCs and BMSC-EVs were isolated and identified, the BMSC-EV function was evaluated by hematoxylin-eosin and Masson staining, immunohistochemistry, quantitative real-time PCR, Cell Counting Kit-8 assay, flow cytometry, enzyme-linked immunosorbent assay, and Transwell and tubule formation assays. The BMSC-EV mechanism was assessed using Western blot, ubiquitination, and cycloheximide-chase assays. After isolation and identification, BMSC-EVs were effective in endometrial injury repair in vivo and facilitated EEC proliferation and repressed cell apoptosis in vitro; the EEC supernatants accelerated human umbilical vein endothelial cell proliferation, migration, and invasion and facilitated angiogenesis after endometrial injury in vitro. For the BMSC-EV mechanism, E3 ubiquitin ligase WWP1 in BMSC-EVs mediated the ubiquitination of peroxisome proliferator-activated receptor gamma (PPARγ), thus relieving the PPARγ inhibition on vascular endothelial growth factor expression. Furthermore, the WWP1 in BMSC-EVs alleviated endometrial injury in vitro and in vivo. BMSC-EVs facilitated endometrial injury repair by carrying WWP1.

Fast, strong, and reversible adhesives with dynamic covalent bonds for potential use in wound dressing.

Adhesives typically fall into two categories: those that have high but irreversible adhesion strength due to the formation of covalent bonds at the interface and are slow to deploy, and others that are fast to deploy and the adhesion is reversible but weak in strength due to formation of noncovalent bonds. Synergizing the advantages from both categories remains challenging but pivotal for the development of the next generation of wound dressing adhesives. Here, we report a fast and reversible adhesive consisting of dynamic boronic ester covalent bonds, formed between poly(vinyl alcohol) (PVA) and boric acid (BA) for potential use as a wound dressing adhesive. Mechanical testing shows that the adhesive film has strength in shear of 61 N/cm2 and transcutaneous adhesive strength of 511 N/cm2, generated within 2 min of application. Yet the film can be effortlessly debonded when exposed to excess water. The mechanical properties of PVA/BA adhesives are tunable by varying the cross-linking density. Within seconds of activation by water, the surface boronic ester bonds in the PVA/BA film undergo fast debonding and instant softening, leading to conformal contact with the adherends and reformation of the boronic ester bonds at the interface. Meanwhile, the bulk film remains dehydrated to offer efficient load transmission, which is important to achieve strong adhesion without delamination at the interface. Whether the substrate surface is smooth (e.g., glass) or rough (e.g., hairy mouse skin), PVA/BA adhesives demonstrate superior adhesion compared to the most widely used topical skin adhesive in clinical medicine, Dermabond.

Distribution and assessment of heavy metals in suspended particles in the Sundarban mangrove river, Bangladesh.

The suspended particulate matter (SPM) is an important carrier of heavy metals transportation from land to sea, so it is significant to study the heavy metal pollution in SPM. The distribution and assessment of five heavy metals (Mn, Cr, Ni, Cu, and Pb) in SPM collected from Passur River and its estuary in Sundarban were studied in combination with water temperature, salinity, and turbidity. The results show that the heavy metal content and distribution in SPM are mainly controlled by runoff input, hydrodynamic process and the interaction process of salt and fresh water in estuaries. The quality evaluation results of heavy metals in SPM show that pollution degree is light. Studies on the heavy metals in SPM are of great significance to comprehensively evaluate regional pollution status and carry out early warning.

Species diversity and community structure of microalgae living on microplastics in Luoyuan Bay, China.

This study was carried out in Luoyuan Bay in March 2021. The species composition of microalgae community colonizing on microplastics called epimicroplastic microalgae (EMP-MA) was analyzed and compared with planktonic microalgae (PM) community. The species number of EMP-MA community (73) was higher than that of PM community (56). However Simpson Index and Pielou Evenness Index of EMP-MA community were significantly lower than that of PM community (P < 0.05). Although diatom was the most diverse and abundant taxa in both EMP-MA and PM community, their species compositions were significantly different (P < 0.05). Dominant species were also different between the two communities. Moreover, 12 harmful algal species were found in EMP-MA community, which may drift with microplastics and increase the risks of harmful algal blooms (HABs). This study is helpful to reveal the dispersal mechanism of HABs and potential impacts of EMP-MA on marine ecosystem.

Strain-stiffening seal.

An elastomeric seal needs to be soft to accommodate installation but stiff to block fluid flow. Here we show that the two requirements are better fulfilled by a strain-stiffening elastomer than a neo-Hookean elastomer. We represent the strain-stiffening elastomer using the Gent model, and calculate the deformation in the elastomeric seal using an approach analogous to the lubrication theory of a viscous fluid between rigid walls. We determine the sealing pressure on the basis of two modes of leak. The seal leaks by elastic deformation when the fluid pressure exceeds the contact pressure between the seal and the rigid wall. The seal leaks by rupture when the energy release rate of a crack exceeds the toughness of the elastomer. For both modes of leak, a strain-stiffening elastomer enhances the sealing pressure compared to a neo-Hookean elastomer. We construct diagrams in which the two modes of leak are demarcated. It is hoped that this study will aid in the development of materials and geometries of seals.

Optoionic Sensing.

The eye converts an optical signal to an ionic signal. This transduction is mimicked here using a photodiode in contact with ionic conductors, such as hydrogels. Photons generate electron-hole pairs in the photodiode. The photodiode/hydrogel interface forms capacitive coupling so that movements of electrons and holes in the photodiode induce movements of ions in the hydrogels. The hydrogels can be readily made stretchable and biocompatible to mimic the function of nerves. When light is turned on and off, the voltage between the hydrogels responds within 10 ms, comparable to the response in the human eye. A photosensitive skin is demonstrated to generate a voltage in response to light but not to stretch. Furthermore, a photosensitive actuation is demonstrated to mimic the light-triggered reflex, such as blinking of the eye and camouflage of the skin. Optoionic transduction has potential applications for wearable devices, implantable devices, and robotics.

Harmful algal blooms caused by Phaeocystis globosa from 1997 to 2018 in Chinese coastal waters.

From 1997 to 2018, Phaeocystis globosa caused harmful algal blooms in Chinese coastal waters almost every year. In this study, the spatial and temporal distribution of P. globosa blooms and its influencing factors were discussed. The results showed that 80.6% of the P. globosa blooms happened in the South China Sea and 72.5% happened in the period from November to March of the following year. But in the Yellow Sea, P. globosa blooms might be limited by green tides. Among the influencing factors, temperature might be an important one that affected the spatial and temporal distribution of P. globosa blooms. Furthermore, eutrophication provided material basis and El Nino events might also stimulate the occurrence of P. globosa blooms. This study is helpful to reveal causes and mechanisms of P. globosa blooms and reduce the negative impacts of blooms on ecological environment, economic development and the safety of nuclear power plants.

Low-Voltage Reversible Electroadhesion of Ionoelastomer Junctions.

Electroadhesion provides a simple route to rapidly and reversibly control adhesion using applied electric potentials, offering promise for a variety of applications including haptics and robotics. Current electroadhesives, however, suffer from key limitations associated with the use of high operating voltages (>kV) and corresponding failure due to dielectric breakdown. Here, a new type of electroadhesion based on heterojunctions between iono-elastomer of opposite polarity is demonstrated, which can be operated at potentials as low as ≈1 V. The large electric field developed across the molecular-scale ionic double layer (IDL) when the junction is placed under reverse bias allows for strong adhesion at low voltages. In contrast, under forward bias, the electric field across the IDL is destroyed, substantially lowering the adhesion in a reversible fashion. These ionoelastomer electroadhesives are highly efficient with respect to the force capacity per electrostatic capacitive energy and are robust to defects or damage that typically lead to catastrophic failure of conventional dielectric electroadhesives. The findings provide new fundamental insight into low-voltage electroadhesion and broaden its possible applications.

Ionoelastomer junctions between polymer networks of fixed anions and cations.

Soft ionic conductors have enabled stretchable and transparent devices, but liquids in such devices tend to leak and evaporate. In this study, we demonstrate diodes and transistors using liquid-free ionoelastomers, in which either anions or cations are fixed to an elastomer network and the other ionic species are mobile. The junction of the two ionoelastomers of opposite polarity yields an ionic double layer, which is capable of rectifying and switching ionic currents without electrochemical reactions. The entropically driven depletion of mobile ions creates a junction of tough adhesion, and the stretchability of the junction enables electromechanical transduction.

Association between social and family support and antenatal depression: a hospital-based study in Chengdu, China.

BACKGROUND: Antenatal depression (AD) is considered as one of the major health burdens and has adverse effects on the outcome of expectant mothers and newborns. The present study aims to investigate the prevalence of antenatal depression (AD), and to explore the potential risk factors of AD among pregnant women in Chengdu, including personal background, related social factors, family factors and cognitive factors. METHODS: The prospective nested case-control study included pregnant women who were in their second pregnancy and attended prenatal care at three tertiary hospitals and one regional hospital in Chengdu, China, between March 2015 and May 2016. Self-designed questionnaires were given to participants in their second and third trimesters to collect information on clinical and demographic characteristics, and a modified edition of Edinburgh Postnatal Depression Scale (EPDS) were used to measure AD. The logistic regression was applicated in analyses. RESULTS: A total of 996 pregnant women were included in analysis. Ninety-three women suffered from AD symptoms only in their second trimester, 96 only in their third trimester, and 107 displayed persistent depression in both trimesters. In the univariate analyses, age and marital relationships were linked with AD occurrence in both second and third trimester. In addition, increasing age, full-time job, higher education level, and no gender preference of spouse were associated with reduced persistent depression. Multivariate analysis showed that gender preference and marital relationship were the potential risk factors of persistent depression. CONCLUSIONS: Age, marital relationship relationships, with parents-in-law, the negative recognition of this pregnancy and husband's gender preference were found as risk factors of AD occurrence in some specific trimester. Gender preference of husbands and marital relationships were independently associated with persistent depression. These findings suggest that stronger family support can help improve mental health of pregnant women.

Molecular Staples for Tough and Stretchable Adhesion in Integrated Soft Materials.

The integration of soft materials-biological tissues, gels, and elastomers-is a rapidly developing technology of this time. Whereas hard materials are adhered using adhesives of hard polymers since antiquity, these hard polymers are generally unsuited to adhere soft materials, because hard polymers constrain the deformation of soft materials. This paper describes a design principle to use hard polymers to adhere soft materials, such that adhesion remains tough after the adhered soft materials are subject to many cycles of large stretches in the plane of their interface. The two soft materials have stretchable polymer networks, but need not have functional groups for adhesion. The two soft materials are adhered by forming, in situ at their interface, islands of a hard polymer. The adhesion is tough if the islands themselves are strong, and the polymers of the islands are in topological entanglement with the polymer networks of the soft materials. The adhesion is stretchable if the islands are smaller than the flaw sensitivity length. Several methods of forming the hard polymer islands are demonstrated, and the mechanics and chemistry of adhesion are studied. The design principle will enable many hard polymers to form tough and stretchable adhesion between soft materials.

Electroluminescence of Giant Stretchability.

A new type of electroluminescent device achieves giant stretchability by integrating electronic and ionic components. The device uses phosphor powders as electroluminescent materials, and hydrogels as stretchable and transparent ionic conductors. Subject to cyclic voltage, the phosphor powders luminesce, but the ionic conductors do not electrolyze. The device produces constant luminance when stretched up to an area strain of 1500%.

Highly stretchable and transparent ionogels as nonvolatile conductors for dielectric elastomer transducers.

Large deformation of soft materials is harnessed to provide functions in the nascent field of soft machines. This paper describes a new class of systems enabled by highly stretchable, transparent, stable ionogels. We synthesize an ionogel by polymerizing acrylic acid in ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([C2mim][EtSO4]). The ionogel exhibits desired attributes of adequate conductivity (0.22 S m(-1)), low elastic modulus (∼3 kPa), large rupturing stretch (∼4.6), and negligible hysteresis and degradation after cyclic stretches of large amplitude. Using the ionogel and a dielectric elastomer, we fabricate electromechanical transducers that achieve a voltage-induced areal strain of 140%. The ionogel is somewhat hygroscopic, but the transducers remain stable after a million cycles of excitation in a dry oven and in air. The transparency of the ionogels enable the transducers with conductors placed in the path of light, and the nonvolatility of the ionogels enable the transducers to be used in open air.

Hierarchical recruitment by AMPA but not staurosporine of pro-apoptotic mitochondrial signaling in cultured cortical neurons: evidence for caspase-dependent/independent cross-talk.

Excitotoxicity mediated via the (S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) subtype of receptor for l-glutamate contributes to various neuropathologies involving acute brain injury and chronic degenerative disorders. In this study, AMPA-induced neuronal injury and staurosporine (STS)-mediated apoptosis were compared in primary neuronal cultures of murine cerebral cortex by analyzing indices up- and downstream of mitochondrial activation. AMPA-mediated apoptosis involved induction of Bax, loss of mitochondrial transmembrane potential (deltapsi(m)), early release of cytochrome c (cyt c), and more delayed release of second mitochondrial activator of caspases (SMAC), Omi, and apoptosis-inducing factor (AIF) with early calpain and minor late activation of caspase 3. STS-induced apoptosis was characterized by a number of differences, a more rapid time course, non-involvement of deltapsi(m), and relatively early recruitment of SMAC and caspase 3. The AMPA-induced rise in intracellular calcium appeared insufficient to evoke feltapsi(m) as release of cyt c preceded mitochondrial depolarization, which was followed by the cytosolic translocation of SMAC, Omi, and AIF. Bax translocation preceded cyt c release for both stimuli inferring its involvement in apoptotic induction. Inclusion of the broad spectrum caspase inhibitor zVAD-fmk reduced the AMPA-induced release of cyt c, SMAC, and AIF, while only affecting the redistribution of Omi and AIF in the STS-treated neurons. Only AIF release was affected by a calpain inhibitor (calpastatin) which exerted relatively minor effects on the progression of cellular injury. AMPA-mediated release of apoptogenic proteins was more hierarchical relative to STS with its calpain activation and caspase-dependent AIF redistribution arguing for a model with cross-talk between caspase-dependent/independent apoptosis.

Relative timing of redistribution of cytochrome c and Smac/DIABLO from mitochondria during apoptosis assessed by double immunocytochemistry on mammalian cells.

Redistribution of cytochrome c and Smac/DIABLO from mitochondria occurs during apoptosis, although the relative timing of their release is not well characterized. Double immunocytochemistry was utilized here to study quantitatively the patterns of release of cytochrome c and Smac/DIABLO from mitochondria in single cells. Human osteosarcoma cells and murine embryonic cortical neurons were analyzed during apoptosis induced by staurosporine. In osteosarcoma cells treated with staurosporine for 24 h, a substantial proportion of cells (36%) released cytochrome c from the mitochondria before Smac/DIABLO. In contrast, these proteins were released mostly concordantly in neurons; only a minority of cells (< or = 15%) released cytochrome c without Smac/DIABLO (or vice versa) from mitochondria. Patterns of release in either cell type were unaltered by addition of the caspase inhibitor, zVAD-fmk. The double immunocytochemistry procedure facilitated clear definition of the temporal release of cytochrome c and Smac/DIABLO from mitochondria in intact apoptotic cells, enabling us to demonstrate for the first time that their mutual redistribution during apoptosis varies between different cell types.