Amorphous Calcium Carbonate Cluster Nanospheres in Water-Deficient Organic Solvents.

As the key intermediate phase of crystalline calcium carbonate biominerals, amorphous calcium carbonate (ACC) remains mysterious in its structures because of its long-range disorder and instability. We herein report the synthesis of ACC nanospheres in a water-deficient organic solvent system. The obtained ACC nanospheres are very stable under dry conditions. Cryo-TEM reveals that each nanospheres consists of smaller nanosized clusters. We further demonstrate that these clusters can precipitate on other substrates to form an ultrathin ACC coating, which should be an ACC cluster monolayer. The results demonstrate that the presence of small ACC clusters as the subunits of larger aggregates is inherent to ACC synthesized in water-alcohol system but not induced by polymer additives.

Small molecule inhibitors targeting the PD-1/PD-L1 signaling pathway.

Tumor cells form immune escape and subsequently obtain unlimited proliferation ability due to the abnormal immune surveillance mediated by immune checkpoints. Among this class of immune checkpoints, PD-1/PD-L1 was recognized as an anticancer drug target for many years, and so far, several monoclonal antibodies have achieved encouraging outcome in cancer treatment by targeting the PD-1/PD-L1 signaling pathway. Due to the inherent limitations of antibodies, the development of small molecule inhibitors based on PD-1/PD-L1 signaling pathway is gradually reviving in decades. In this review, we summarized a number of small molecule inhibitors based on three different therapeutic approaches interfering PD-1/PD-L1 signaling pathway: (1) blocking direct interaction between PD-1 and PD-L1; (2) inhibiting transcription and translation of PD-L1; and (3) promoting degradation of PD-L1 protein. The development of these small molecule inhibitors opens a new avenue for tumor immunotherapy based on PD-1/PD-L1 signaling pathway.

Wood-Derived Ultrathin Carbon Nanofiber Aerogels.

Carbon aerogels with 3D networks of interconnected nanometer-sized particles exhibit fascinating physical properties and show great application potential. Efficient and sustainable methods are required to produce high-performance carbon aerogels on a large scale to boost their practical applications. An economical and sustainable method is now developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels from the wood-based nanofibrillated cellulose (NFC) aerogels via a catalytic pyrolysis process, which guarantees high carbon residual and well maintenance of the nanofibrous morphology during thermal decomposition of the NFC aerogels. The wood-derived CNF aerogels exhibit excellent electrical conductivity, a large surface area, and potential as a binder-free electrode material for supercapacitors. The results suggest great promise in developing new families of carbon aerogels based on the controlled pyrolysis of economical and sustainable nanostructured precursors.

Bioinspired High-Magnesium Calcite for Efficiently Reducing Chemical Oxygen Demand in Lake Water.

Organic matter accumulation in water can cause serious problems such as oxygen depletion and quality deterioration of waters. While calcium carbonate has been used as green and low-cost adsorbent for water treatment, its efficiency in reducing the chemical oxygen demand (COD) of water, which is a measure of organic pollution, is restrained by the limited specific surface area and chemical activity. Herein, inspired by the high-magnesium calcite (HMC) found in biological materials, a feasible method to synthesize fluffy dumbbell-like HMC with large specific surface area is reported. The magnesium inserting increases the chemical activity of the HMC moderately but without lowering its stability too much. Therefore, the crystalline HMC can retain its phase and morphology in aqueous environment for hours, which allows the establishment of adsorption equilibrium between the solution and the adsorbent that retains its initial large specific surface area and improved chemical activity. Consequently, the HMC exhibits notably enhanced capability in reducing the COD of lake water polluted by organics. This work provides a synergistic strategy to rationally design high-performance adsorbents by simultaneously optimizing the surface area and steering the chemical activity.

General Synthesis and Solution Processing of Metal-Organic Framework Nanofibers.

By virtue of their extraordinarily high surface areas, ordered pore structures, various compositions, and rich functionality, metal-organic frameworks (MOFs) are of great interest in diverse fields such as gas separation, sensing, catalysis, energy, environment science, and biomedicine. However, the difficulty in processing MOF crystals and controlling the MOF superstructure is emerging as a critical issue in their application. Herein, it is reported that a robust template, i.e., nanofibrillated cellulose (NFC), can be used for the synthesis of MOF materials with 1D nanofiber morphology. NFC@MOF core-shell nanofibers with a uniform network structure and high aspect ratios can be prepared by use of this template. The small crystal size, flexibility, and good dispersity of the NFC@MOF nanofibers make it convenient for the macroscale assembly and solution processing of MOF materials. A proof-of-concept study is demonstrated wherein freestanding MOF nanofiber membranes represent good performance in applications of water treatment and heterogeneous catalysis reaction. This general synthesis and solution-processing strategy may herald a new era in promoting the industrial application of MOFs.

Role of defensins in diabetic wound healing.

The adverse consequences resulting from diabetes are often presented as severe complications. Diabetic wounds are one of the most commonly occurring complications in diabetes, and the control and treatment of this is costly. Due to a series of pathophysiological mechanisms, diabetic wounds remain in the inflammatory phase for a prolonged period of time, and face difficulty in entering the proliferative phase, thus leading to chronic non-healing wounds. The current consensus on the treatment of diabetic wounds is through multidisciplinary comprehensive management, however, standard wound treatment methods are still limited and therefore, more effective methods are required. In recent years, defensins have been found to play diverse roles in a variety of diseases; however, the molecular mechanisms underlying these activities are still largely unknown. Defensins can be constitutively or inductively produced in the skin, therefore, their local distribution is affected by the microenvironment of these diabetic wounds. Current evidence suggests that defensins are involved in the diabetic wound pathogenesis, and can potentially promote the early completion of each stage, thus making research on defensins a promising area for developing novel treatments for diabetic wounds. In this review, we describe the complex function of human defensins in the development of diabetic wounds, and suggest potential thera-peutic benefits.

Natural Nanofibrous Cellulose-Derived Solid Acid Catalysts.

Solid acid catalysts (SACs) have attracted continuous research interest in past years as they play a pivotal role in establishing environmentally friendly and sustainable catalytic processes for various chemical industries. Development of low-cost and efficient SACs applicable to different catalysis processes are of immense significance but still very challenging so far. Here, we report a new kind of SACs consisting of sulfonated carbon nanofibers that are prepared via incomplete carbonization of low-cost natural nanofibrous cellulose followed by sulphonation with sulfuric acid. The prepared SACs feature nanofibrous network structures, high specific surface area, and abundant sulfonate as well as hydroxyl and carboxyl groups. Remarkably, the nanofibrous SACs exhibit superior performance to the state-of-the-art SACs for a wide range of acid-catalyzed reactions, including dimerization of α-methylstyrene, esterification of oleic acid, and pinacol rearrangement. The present approach holds great promise for developing new families of economic but efficient SACs based on natural precursors via scalable and sustainable protocols in the future.

Superelastic Hard Carbon Nanofiber Aerogels.

Superelastic carbon aerogels have been widely explored by graphitic carbons and soft carbons. These soft aerogels usually have delicate microstructures with good fatigue resistance but ultralow strength. Hard carbon aerogels show great advantages in mechanical strength and structural stability due to the sp3 -C-induced turbostratic "house-of-cards" structure. However, it is still a challenge to fabricate superelastic hard carbon-based aerogels. Through rational nanofibrous structural design, the traditional rigid phenolic resin can be converted into superelastic hard carbon aerogels. The hard carbon nanofibers and abundant welded junctions endow the hard carbon aerogels with robust and stable mechanical performance, including superelasticity, high strength, extremely fast recovery speed (860 mm s-1 ), low energy-loss coefficient (<0.16), long cycle lifespan, and heat/cold-endurance. These emerging hard carbon nanofiber aerogels hold a great promise in the application of piezoresistive stress sensors with high stability and wide detection range (50 kPa), as well as stretchable or bendable conductors.

Distinctive functional deficiencies in axonal conduction associated with two forms of cerebral white matter injury.

AIMS: This study determines whether assessment with compound action potentials (CAPs) can distinguish two different forms of cerebral white matter injury at the functional levels. METHODS: A pure demyelination model was induced in C57/BL6 adult mice by dietary supplementation of cuprizone (0.2%) for 6 weeks. Callosal L-N5-(1-Iminoethyl) ornithine (L-NIO) hydrochloride (27 mg/mL) was injected into the corpus callosum (CC) to induce a focal white matter stroke (WMS), resulting in both demyelination and axonal injury. White matter integrity was assessed by performing CAP recording, electron microscopy, and immunohistological and luxol fast blue (LFB) staining. RESULTS: Immunohistological and electron microscopic analyses confirmed the induction of robust demyelination in CC with cuprizone, and mixed demyelination and axonal damage with L-NIO. Electrophysiologically, cuprizone-induced demyelination significantly reduced the amplitude of negative peak 1 (N1), but increased the amplitude of negative peak 2 (N2), of the CAPs compared to the sham controls. However, cuprizone did not affect the axonal conduction velocity. In contrast, the amplitude and area of both N1 and N2 along with N1 axonal conduction velocity were dramatically decreased in L-NIO-induced WMS. CONCLUSIONS: Concertedly, parameters of the CAPs offer a novel functional assessment strategy for cerebral white matter injury in rodent models.

Gut microbiota profiling in Han Chinese with type 1 diabetes.

AIMS: To investigate whether microbial dysbiosis is associated with T1D in Chinese population and to explore relationships between the composition of gut microbiome and clinical data. METHODS: In this study, we recruited 10 healthy and 12 T1D Han Chinese subjects between the ages of 12 to 33. Fecal samples were collected for DNA extraction and 16S rRNA sequencing, followed by analyses of the gut microbiota composition. RESULTS: Bacterial communities differed between healthy and T1D subjects. At the phylum level, Bacteroidetes and Firmicutes are the dominant phyla in T1D patients and healthy controls, respectively. The linear discriminant analysis (LDA) effect size (LEfSe) algorithm detected 28 bacterial taxonomic clades showing statistically differences (13 increased and 15 decreased) in T1D patients. Association analyses of clinical data and microbial community abundance demonstrated that abundances of Faecalibacterium were negatively correlated with HbA1c levels (Z = -2.614, P = 0.017). The numbers of detected anti-islet cell autoantibodies were positively correlated with Bacteriodes (Z = 2.531, P = 0.011) and Bilophila (Z = 2.477, P = 0.013) abundances, while negatively correlated with abundances of Streptococcus (Z = -2.041, P = 0.041) and Ruminococcaceae (Z = -2.23, P = 0.026). CONCLUSIONS: These results suggest that Han Chinese T1D patients possess distinctly different gut microbiota, compared to healthy subjects, characterized by increased Bacteroidetes/Firmicutes ratio, negative correlation of Faecalibacterium abundance with HbA1c, and positive correlation of Bacteroides abundance with the presence of autoantibodies.

Bioinspired polymeric woods.

Woods provide bioinspiration for engineering materials due to their superior mechanical performance. We demonstrate a novel strategy for large-scale fabrication of a family of bioinspired polymeric woods with similar polyphenol matrix materials, wood-like cellular microstructures, and outstanding comprehensive performance by a self-assembly and thermocuring process of traditional resins. In contrast to natural woods, polymeric woods demonstrate comparable mechanical properties (a compressive yield strength of up to 45 MPa), preferable corrosion resistance to acid with no decrease in mechanical properties, and much better thermal insulation (as low as ~21 mW m-1 K-1) and fire retardancy. These bioinspired polymeric woods even stand out from other engineering materials such as cellular ceramic materials and aerogel-like materials in terms of specific strength and thermal insulation properties. The present strategy provides a new possibility for mass production of a series of high-performance biomimetic engineering materials with hierarchical cellular microstructures and remarkable multifunctionality.

[Effects of yixintong on regulating cellular calcium channels].

OBJECTIVE: To explore the protecting mechanism of Yixintong for heart ischemia-reperfusion injury at cellular and subcellular levels, by observing the effects of Yixintong on three kinds of calcium channels. METHOD: The effects of Yixintong on Ca2+ influx on leak calcium channel, receptor-operationg calcium channel (ROC) and pulse-dependent calcium channel (PDC) were observed respectively, by using rat aortic smooth muscle cell and radioactive 45Ca technique. RESULT: Yixintong has no effects on leak calcium channel, but can inhibit the Ca2+ influx in ROC and PDC significantly. CONCLUSION: Yixintong can inhibit the Ca2+ influx in slow channel in a dose-dependent manner.

Density functional study of structural and electronic properties of small binary Be(n)Cu(m) (n + m = 2~7) clusters.

The geometrical structures, electronic properties and relative stabilities of small bimetallic Be n Cu m (n + m = 2-7) clusters have been systematically investigated by using a density functional method at the B3PW91 level. In the most stable structures of Be n Cu m , the Be atoms tend to gather together and construct similar configurations to those of pure Be n clusters. Meanwhile, there is a tendency for Cu atoms to segregate toward the Be n cluster surface. The successive binding energies, cohesive energies, second difference of energies, the highest occupied-lowest unoccupied molecular orbital energy gaps and chemical hardness of Be n Cu m are also investigated. All of them demonstrate that the clusters with even number of copper atoms present relatively higher stabilities. The natural population analyses on the Be n Cu m clusters reveal that, the charge transfers from Be to Cu when the average coordination numbers (Nc) of Be atom is less than 3, whereas the charge-transferring direction reverses when Nc(Be) increases.