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Icing and frosting on transparent surfaces compromise visibility on various optical equipment and transparent infrastructures. It remains challenging to fabricate energy-saving coatings for harvesting solar energy while maintaining high transparency. Here, transparent, photothermic, and icephobic composite surfaces composed of photothermal nanomaterials and polyelectrolytes via layer-by-layer assembly are designed and constructed. The positively-charged polypyrrole nanoparticles and negatively-charged poly(acrylic acid) are assembled as exemplary materials via electrostatic attractions. The optically transparent photothermal coatings are successfully fabricated and exhibited photothermal capabilities and light-transmittance performance. Among the various coatings applied, the seven-bilayer coating can increase the temperature by 35 °C under 1.9-sun illumination, maintaining high transmittance (>60%) of visible light. With sunlight illumination at subzero temperatures (> -35 °C), the coatings show pronounced capabilities to inhibit freezing, melt accumulated frost, and decrease ice adhesion. Precisely, the icephobic surfaces remain free of frost at -35 °C as long as sunlight illumination is present; the accumulated frost melts rapidly within 300 s. The ice adhesion strength decreases to ≈0kPa as the melted water acts as a lubricant. Furthermore, the negatively-charged graphene oxide and positively-charged poly(diallyldimethylammonium chloride) show their material diversity applicable in the coating fabrication.

Assisted reproductive technology has important clinical applications and commercial values in the horse industry. However, this approach is limited largely by the low efficiency of oocyte in vitro maturation (IVM), especially cytoplasmic maturation. To improve the efficiency of mare oocyte IVM, we evaluated the effects of co-culture with cumulus–oocyte complexes (COCs) and granulosa cells (GCs) from follicles with small (35 mm). Our results showed that oocyte nucleus maturation was not significantly improved by co-culturing with GCs. Interestingly, the cytoplasmic maturation of oocytes, defined by the distribution of cortical granules and mitochondria, as well as reactive oxygen species (ROS) levels, improved dramatically by co-culture with GCs, especially those derived from small follicles. Moreover, GCs promoted cumulus cell expansion by upregulating the expression of BMP15 in oocytes. To determine the mechanism underlying the effects of GCs, the transcriptomes of GCs from large and small follicles were compared. Expression levels of COL1A2, COL6A1, and COL6A2 were significantly higher in GCs from small follicles than in those from large follicles. These three genes were enriched in the extracellular matrix proteins-receptor interaction pathway and were involved in the regulation of collagens. Taken together, our results suggest that co-culture with GCs is beneficial to oocyte cytoplasmic maturation, and the increased expression of COL1A2, COL6A1, and COL6A2 improve the mare oocyte IVM system via the regulation of collagen.

Recommender systems suffer from confounding biases when there exist confounders affecting both item features and user feedback (e.g., like or not). Existing causal recommendation methods typically assume confounders are fully observed and measured, forgoing the possible existence of hidden confounders in real applications. For instance, product quality is a confounder since affecting both item prices and user ratings, but is hidden for the third-party e-commerce platform due to the difficulty of large-scale quality inspection; ignoring it could result in the bias effect of over-recommending high-price items. This work analyzes and addresses the problem from a causal perspective. The key lies in modeling the causal effect of item features on a user's feedback. To mitigate hidden confounding effects, it is compulsory but challenging to estimate the causal effect without measuring the confounder. Towards this goal, we propose a Hidden Confounder Removal (HCR) framework that leverages front-door adjustment to decompose the causal effect into two partial effects, according to the mediators between item features and user feedback. The partial effects are independent from the hidden confounder and identifiable. During training, HCR performs multi-task learning to infer the partial effects from historical interactions. We instantiate HCR for two scenarios and conduct experiments on three real-world datasets. Empirical results show that the HCR framework provides more accurate recommendations, especially for less-active users. We will release the code once accepted.

Stimuli-responsive hydrogels have large deformability but-when applied as actuators, smart switch, and artificial muscles-suffer from low work density due to low deliverable forces (~2 kPa) and speed through the osmotic pressure-driven actuation. Inspired by the energy conversion mechanism of many creatures during jumping, we designed an elastic-driven strong contractile hydrogel through storing and releasing elastic potential energy in polymer network. It can generate high contractile force (40 kPa) rapidly at ultrahigh work density (15.3 kJ/m3), outperforming current hydrogels (~0.01 kJ/m3) and even biological muscles (~8 kJ/m3). This demonstrated elastic energy storing and releasing method endows hydrogels with elasticity-plasticity switchability, multi-stable deformability in fully reversible and programmable manners, and anisotropic or isotropic deformation. With the high power density and programmability via this customizable modular design, these hydrogels demonstrated potential for broad applications in artificial muscles, contractile wound dressing, and high-power actuators.

Ice accumulation causes various problems in our daily life for human society. The daunting challenges in ice prevention and removal call for novel efficient antiicing strategies. Recently, photothermal materials have gained attention for creating icephobic surfaces owing to their merits of energy conservation and environmental friendliness. However, it is always challenging to get an ideal photothermal material which is cheap, easily fabricating, and highly photothermally efficient. Here, we demonstrate a low-cost, high-efficiency superhydrophobic photothermal surface, uniquely based on inexpensive commonly seen candle soot. It consists of three components: candle soot, silica shell, and polydimethylsiloxane (PDMS) brushes. The candle soot provides hierarchical nano/microstructures and photothermal ability, the silica shell strengthens the hierarchical candle soot, and the grafted low-surface-energy PDMS brushes endow the surface with superhydrophobicity. Upon illumination under 1 sun, the surface temperature can increase by 53 °C, so that no ice can form at an environmental temperature as low as -50 °C and it can also rapidly melt the accumulated frost and ice in 300 s. The superhydrophobicity enables the melted water to slide away immediately, leaving a clean and dry surface. The surface can also self-clean, which further enhances its effectiveness by removing dust and other contaminants which absorb and scatter sunlight. In addition, after oxygen plasma treatment, the surface can restore superhydrophobicity with sunlight illumination. The presented icephobic surface shows great potential and broad impacts owing to its inexpensive component materials, simplicity, ecofriendliness, and high energy efficiency.

The recent anti-icing strategies in the state of the art mainly focused on three aspects: inhibiting ice nucleation, preventing ice propagation, and decreasing ice adhesion strength. However, it is has proved difficult to prevent ice nucleation and propagation while decreasing adhesion simultaneously, due to their highly distinct, even contradictory design principles. In nature, anti-freeze proteins (AFPs) offer a prime example of multifunctional integrated anti-icing materials that excel in all three key aspects of the anti-icing process simultaneously by tuning the structures and dynamics of interfacial water. Here, inspired by biological AFPs, we successfully created a multifunctional anti-icing material based on polydimethylsiloxane-grafted polyelectrolyte hydrogel that can tackle all three aspects of the anti-icing process simultaneously. The simplicity, mechanical durability, and versatility of these smooth hydrogel surfaces make it a promising option for a wide range of anti-icing applications.

Naval Postgraduate School Acquisition Research Program

A Symposium Presentation Naval Postgraduate School Naval Postgraduate School Acquisition Research Program

This paper deals with a nutrient cycling experiment in the Beijing Zoo that uses macrophytes as the added link to make a purification system. The whole system consisted of macrophyte cultivating area and no macrophyte area. By making up the different functional groups of aquatic plants, a multilevel cycling network is formed, which has a rather high purification capability. During the experimental period, the water quality of the Waterfowl Lake and the Peony Pavilion Lake improved significantly, with total nitrogen and total phosphorus reductions of up to 58 and 38%, respectively. Other parameters also confirmed the good purification effect of this system. The economic and social benefits met the requirement of the original design.

Objectives To evaluate the anti-apoptotic effect of Shenyuan, which is composed of the bioactive components extracted from the mixture of American Ginseng and Corydalis Tuber, and to explore the inhibition of endoplasmic reticulum stress (ERS) and oxidative stress involved in the regulation of apoptosis in cardiac myocytes. Methods A porcine model of acute myocardial infarction (AMI) was established by ligation of the left anterior descending coronary artery. Pigs were randomised into 6 study groups: Group S, sham (n = 6); Group C, myocardial infarction controls (n = 8); Group L, MI + low-dose Shenyuan (240 mg/kg•d, n = 6); Group M, MI + medium-dose Shenyuan (320 mg/kg•d, n = 6); Group H, MI + high-dose Shenyuan (400 mg/kg•d, n = 6); Group B, MI + Metoprolol Tartrate (1 mg/kg•d, n = 6). The treatment of Shenyuan or Metoprolol started at one week before MI and continued for another two weeks after MI. Results Treatment with all doses of Shenyuan as well as Metoprolol produced a significant decrease of apoptotic index ( p p Conclusions Shenyuan treatment, which started at one week before MI and continued for another two weeks after MI, significantly inhibited ERS and oxidative stress, balanced the Bcl-2/Bax ratio, and then suppressed activation of caspase-3, thus exerting an anti-apoptotic effect in pigs with a large anterior wall MI. This was accompanied by less release of cardiac enzymes, and limit of infarct size. Shenyuan treatment inhibited apoptosis and might have a therapeutic role in improving the natural history of MI.

Objective To elucidate whether plasma soluble receptor for advanced glycation end products (sRAGE) is the biochemical markers indicating coronary artery disease and coronary artery disease with acute myocardial infarction (AMI). Method Plasma levels of sRAGE was determined by enzyme linked immunoabsorbent assay in patients who came from Cardiology Department of Tiantan Hospital form March to May 2009 categorised as group I (non-CAD subjects), group II (CAD without myocardial infarction subjects), and group III (CAD with AMI subjects). Results Plasma levels of sRAGE was higher in group III than in group II (p 0.05). Further more, to evaluate whether sRAGE is the biochemical markers indicating the AMI in CAD patients, ROC curve was used, and area under the curve was 0.855(p=0.000). Conclusion sRAGE may be new biochemical markers indicating AMI in the patients with coronary artery disease. The diagnostic sensitivity of sRAGE is 75% and specificity is 86.4%.