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The development of mechanically robust super-lubrication hydrogel materials with sustained lubricity at high contact pressures is challenging. In this work, inspired by the durable lubricity feature of the earthworm epidermis, a multilevel structural super-lubrication hydrogel (MS-SLH) system, the so-called lubricant self-pumping hydrogel, is developed. The MS-SLH system is manufactured by chemically dissociating a double network hydrogel to generate robust and wrinkled lubrication layer, and then laser etching was used to generate cylindrical texture pores as gland-like pockets for storing lubricants. The surface of MS-SLH system shows ultrafast hydration characteristics and reversible pore-closing and pore-opening behavior. The current MS-SLH system shows excellent SL features, as follows: a very low COF (~0.0079) at high contact pressure condition (P: 11.32 MPa); a stable and robust SL lifespan (COF: ~0.0028, P: 8.48 MPa, 100k cylces) without surface wear; and a sustained lubricity period (3700 cycles) with limited lubricant volume (5 μL) in air. The robust and sustained lubricity of the MS-SLH system is likely attributed to the synergy from the strong electrostatic repulsion effect at the sliding interface, the robust but compliant modulus of the dissociation lubrication layer, and the self-pumping lubricant release from the gland-like pocket of the texture pores during the dynamic shearing process. The demonstration experiments based on self-built equipments intuitively exhibit durable SL behavior of MS-SLH system. This work provides an easy strategy for the large-scale manufacture of high-performance water-lubrication coatings suitable for high-end medical devices or moving parts. Developing mechanically robust hydrogels with high lubricity is challenging but desirable. Here, the authors report the development of a layered hydrogel with a robust and wrinkled lubrication layer, and pores for storing lubricants, for sustained lubricity. [ABSTRACT FROM AUTHOR]

Cuprous oxide (Cu2O) is a highly promising photocatalyst that facilitates efficient water splitting and hydrogen production under light conditions. In this study, Cu2O thin film photocathodes were prepared through electro-deposition, with the inclusion of NO 3 - ions resulting in the formation of a flower-like microstructure. The size, distribution and roughness of these clusters were found to be greatly influenced by the concentration of the NO 3 - ions as confirmed by SEM and AFM characterizations. When 0.4 M NO 3 - ions were used, a flat and compact structure with the smallest 'flower bud' was obtained. This structure achieved a maximum photocurrent density of − 2.90 mA/cm2 @0 V vs. RHE, which is 2.2 times greater than that of bare Cu2O. UV–Vis absorption, steady-state fluorescence spectroscopy and EIS measurements suggest that the compact microstructure facilitates enhanced ultraviolet absorption and separation of photogenerated holes and electrons. This results in a lower charge transfer resistance and a significant increase in photocurrent density. Additionally, a growth mechanism for the flower-like Cu2O was proposed. The XPS and EDS analyses indicate that the addition of NO 3 - during Cu2O formation results in the adsorption of NO 3 - onto the surface of the initial Cu2O grain. This, in turn, catalyses the electrocatalytic reduction of NO 3 - on the surface of Cu2O, leading to the formation of NH + 4 ions as evidenced by XPS. [ABSTRACT FROM AUTHOR]

Cartilage is well lubricated over a lifetime and this phenomenon is attributed to both of the surface hydration lubrication and the matrix load-bearing capacity. Lubricious hydrogels with a layered structure are designed to mimic cartilage as potential replacements. While many studies have concentrated on improving surface hydration to reduce friction, few have experimentally detected the relationship between load-bearing capacity of hydrogels and their interface friction behavior. In this work, a bilayer hydrogel, serving as a cartilage prototype consisted of a top thick hydrated polymer brush layer and a bottom hydrogel matrix with tunable modulus was designed to investigate this relationship. The coefficient of friction (COF, μ) is defined as the sum of interfacial component (μInt) and deformation/hysteresis component (μHyst). The presence of the top hydration layer effectively dissipates contact stress and reduces the interface interaction (μInt), leading to a stable and low COF. The contribution of mechanical deformation (μHyst) during the sliding shearing process to COF can be significantly reduced by increasing the local mechanical modulus, thereby enhancing the load-bearing capacity. These results show that the strategy of coupling surface hydration layer with a high load-bearing matrix can indeed enhance the lubrication performance of hydrogel cartilage prototypes, and implies a promising routine for designing robust soft matter lubrication system and friction-control devices. [ABSTRACT FROM AUTHOR]

This study investigated dual-fuel engine performance at high altitude. The test engine was modified from a high-pressure common-rail diesel engine and fuelled with diesel and natural gas. The impact of fuel substitution rate, which is the most critical calibration parameter of dual-fuel engines, on the fuel economy and emissions was studied. Pilot diesel fuel and natural gas flow rates were optimized to minimize fuel consumption while ensuring good combustion stability, emissions, and durability. The advantages of full-load power capability, fuel consumption, and emissions of the dual-fuel engine were revealed with a comparison to the pure diesel engine. This paper also addresses the performance of the dual-fuel engine at high altitudes and reveals its advantages. With an in-cylinder pressure analysis, the test results showed that the dual-fuel engine could achieve higher brake mean effective pressure (BMEP) in a wide range of engine speed compared to the pure diesel engine. When compared at the same operating condition, the dual-fuel engine generally produced much less fuel consumption and emissions, especially at high loads. [ABSTRACT FROM AUTHOR]

A new isocoumarin glucoside, 3S-6-methoxy-8-hydroxy 3-(4-hydroxyphenylethyl)-3,4-dihydroisocoumarin- 8-O-β-D-glucopyranoside (1), along with seven known compounds (2–8) were isolated from the aerial parts of Aruncus sylvester, and their structures were elucidated based on IR, HR-ESI-MS, 1D and 2D NMR spectroscopic data, and XSA. This is the first report of compounds 5–8 from Aruncus sylvester. [ABSTRACT FROM AUTHOR]

Carnitine metabolism is thought to be negatively correlated with the progression of hepatocellular carcinoma (HCC) and the specific molecular mechanism is yet to be fully elucidated. Here, we report that little characterized cysteine‐rich protein 1 (CRIP1) is upregulated in HCC and associated with poor prognosis. Moreover, CRIP1 promoted HCC cancer stem‐like properties by downregulating carnitine energy metabolism. Mechanistically, CRIP1 interacted with BBOX1 and the E3 ligase STUB1, promoting BBOX1 ubiquitination and proteasomal degradation, and leading to the downregulation of carnitine. BBOX1 ubiquitination at lysine 240 is required for CRIP1‐mediated control of carnitine metabolism and cancer stem‐like properties. Further, our data showed that acetylcarnitine downregulation in CRIP1‐overexpressing cells decreased beta‐catenin acetylation and promoted nuclear accumulation of beta‐catenin, thus facilitating cancer stem‐like properties. Clinically, patients with higher CRIP1 protein levels had lower BBOX1 levels but higher nuclear beta‐catenin levels in HCC tissues. Together, our findings identify CRIP1 as novel upstream control factor for carnitine metabolism and cancer stem‐like properties, suggesting targeting of the CRIP1/BBOX1/β‐catenin axis as a promising strategy for HCC treatment. Synopsis: The molecular details of how carnitine energy metabolism regulates liver cancer remain poorly understood. This work identifies zinc finger protein CRIP1 as upstream control factor for carnitine synthesis and oncogenic WNT/beta‐catenin signaling in hepatocellular carcinoma (HCC), suggesting new potential therapeutic avenues. CRIP1 correlates with poor survival in HCC patient samples.CRIP1 downregulates carnitine metabolism and promotes cancer stem‐like properties in HCC cell lines.CRIP1 facilitates interaction of ubiquitin ligase STUB1 and carnitine synthesis enzyme BBOX1, enhancing BBOX1 ubiquitination and proteasomal degradation.CRIP1 overexpression decreased acetylcarnitine levels and beta‐catenin acetylation, promoting nuclear beta‐catenin accumulation.Targeting the CRIP1/BBOX1/beta‐catenin axis impairs HCC in xenograft assays. [ABSTRACT FROM AUTHOR]

In nature, living organisms evolve unique functional components with mechanically adaptive compatibility to cater dynamic change of interface friction/lubrication. This mechanism can be used for developing intelligent artificial lubrication-regulation systems. Inspired by the muscle hardening-triggered lubrication of longsnout catfish, here we report a modulus adaptive lubricating hydrogel prototype consisting of top mucus-like hydrophilic lubricating layer and muscle-like bottom hydrogel that can stiffen via thermal-triggered phase separation. It exhibits instant switch from soft/high frictional state (~0.3 MPa, μ~0.37) to stiff/lubricating state (~120 MPa, μ~0.027) in water upon heating up. Such switchable lubrication is effective for wide range of normal loads and attributed to the modulus-dominated adaptive contact mechanism. As a proof-of-concept, switchable lubricating hydrogel bullets and patches are engineered for realizing controllable interface movements. These important results demonstrate potential applications in the fields of intelligent motion devices and soft robots. Stimuli responsive materials are interesting for applications in different technological fields, but realizing controllable surface friction-control based on the change of the modulus of a material is less investigated. Here the authors demonstrate a lubrication regulating strategy and prototype based on thermally triggered changes of the modulus of a hydrogel. [ABSTRACT FROM AUTHOR]

Lipocalin 2 (LCN2), an immunomodulator, regulates various cellular processes such as iron transport and defense against bacterial infection. Under pathological conditions, LCN2 promotes neuroinflammation via the recruitment and activation of immune cells and glia, particularly microglia and astrocytes. Although it seems to have a negative influence on the functional outcome in spinal cord injury (SCI), the extent of its involvement in SCI and the underlying mechanisms are not yet fully known. In this study, using a SCI contusion mouse model, we first investigated the expression pattern of Lcn2 in different parts of the CNS (spinal cord and brain) and in the liver and its concentration in blood serum. Interestingly, we could note a significant increase in LCN2 throughout the whole spinal cord, in the brain, liver, and blood serum. This demonstrates the diversity of its possible sites of action in SCI. Furthermore, genetic deficiency of Lcn2 (Lcn2−/−) significantly reduced certain aspects of gliosis in the SCI-mice. Taken together, our studies provide first valuable hints, suggesting that LCN2 is involved in the local and systemic effects post SCI, and might modulate the impairment of different peripheral organs after injury. [ABSTRACT FROM AUTHOR]

A new monoterpenoid, arunculactone (1), was obtained from the aerial part of Aruncus sylvester, along with a known monoterpenoid, (–)-loliolide (2). The structure of compound 1 was determined through NMR, HR-ESI-MS, and IR spectra and XSA. This is, to our knowledge, the first report on compounds 1 and 2 from the genus Aruncus. [ABSTRACT FROM AUTHOR]