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The optimum extraction conditions of polysaccharides from roxburgh rose (Rosa roxburghii Tratt.) leaves (RLP) were obtained by response surface methodology (RSM), which were a liquid to solid ratio of 21.16 mL/g, an extraction temperature of 81.32 °C, and an extraction time of 90.49 min. An RLP yield of 11.04% was obtained under these conditions. DEAE-52 cellulose and Sepharose CL-6B columns were used to purify the RLP, and the purified polysaccharide components RLP-1.2 and RLP-2.1 were obtained. Both RLP-1.2 and RLP-2.1 were composed of galacturonic acid (GalA), glucose (Glc), galactose (Gal), and arabinose (Ara). However, the molar ratios of GalA, Glc, Gal, and Ara in RLP-1.2 and RLP-2.1 were different. At a concentration of 10 mg/mL, the α-amylase inhibitory activities of RLP-1.2 and RLP-2.1 reached 80.74% and 89.85% that of acarbose, respectively, and the α-glucosidase inhibitory activity of RLP-1.2 reached 87.91% that of acarbose. In addition, both RLP-1.2 and RLP-2.1 showed good antioxidant activity. These results suggested that RLP-1.2 and RLP-2.1 possess potential as natural hypoglycemic agents or natural antioxidants.

Background This study investigated the prevalence of restraint system use for children passengers in cars, and it assessed parental knowledge and attitudes about such restraint systems in Mianyang, China. Methods A cross-sectional survey was conducted between December 2021 and January 2022. Hospitals and kindergartens in Mianyang were randomly selected for inclusion and parents with cars were surveyed about whether they owned and used child restraint systems and about their knowledge and attitudes towards such systems. Factors associated with CRS use were explored using binary logistic regression. Results A total of 4,764 questionnaires were distributed to families with children 0–6 years old. Among the 4,455 responses received, 50.8% of families owned child restraint systems, most of which were front-facing child seats (42.0%). Just under half of families (44.4%) reported using a child restraint system at least sometimes, but only 19.6% used one all the time. Possession and use of a child restraint system varied significantly with parental education level, age of the child, place of residence, number of children, family income, travel frequency, and travel distance. Logistic regression showed that frequency of car travel with a child and monthly family income significantly affected CRS use. Most parents (85.2%) wrongly believed that adult seat belts in cars are effective at protecting their children in the event of a crash. The most frequent reason that parents cited for not using a child restraint system was that it would lead children to travel in the car less often. Conclusions Although approximately half the parents in our sample owned a child restraint system, most used them rarely, if at all. Educating parents about the safe ways for children to ride in a car and about safety restraint systems and safety belts may promote the use of restraint systems.

Lacking nano-systems for precisely codelivering the chemotherapeutics paclitaxel (PTX) and the natural P-glycoprotein (P-gp) inhibitor, quercetin (QU), into cancer cells and controlling their intracellular release extremely decreased the anticancer effects in multidrug resistant (MDR) tumors. To overcome this hurdle, we constructed hybrid polymeric nanoparticles (PNPs) which consist of redox-sensitive PTX/polyethyleneimine-tocopherol hydrogen succinate-dithioglycollic acid PNPs and pH-sensitive hyaluronic acid-QU conjugates. The obtained hybrid PNPs can be internalized into drug-resistant breast cancer cells by the hyaluronic acid/CD44-mediated endocytosis pathway and escape from the lysosome through the “proton sponge effect”. Under the trigger of intracellular stimuli, the nanoplatform used the pH/glutathione dual-sensitive disassembly to release QU and PTX. The PTX diffused into microtubules to induce tumor cell apoptosis, while QU promoted PTX retention by down-regulating P-gp expression. Moreover, tocopherol hydrogen succinate and QU disturbed mitochondrial functions by generating excessive reactive oxygen species, decreasing the mitochondrial membrane potential, and releasing cytochrome c into the cytosol which consequently achieved intracellular multilevel chemotherapy amplification in MDR cancers. Importantly, the PNPs substantially suppressed tumors growth with an average volume 2.54-fold lower than that of the control group in the MCF-7/ADR tumor-bearing nude mice model. These presented PNPs would provide a valuable reference for the coadministration of natural compounds and anticarcinogens for satisfactory combination therapy in MDR cancers.

SSCN is a new type of self-sensitive photocatalyst. It consists of oxygenated carbon nitride-containing microspheres inside and polymerized triazine dye (TBO) formed on its surface by in situ polymerization. The presence of TBO endows SSCN with a wide range of optical responses. However, the TBO would self-degrade under light, making SSCN extremely unstable in photocatalytic reactions and limiting the practical application of SSCN. The introduction of phosphorus into the structure of SSCN significantly improved the electron–hole separation efficiency and reduced the self-degradation of surface TBO. Phosphorus-doped self-sensitive carbon nitride microspheres (P-SSCN) are easily synthesized by a one-pot solvothermal method—the phosphorus source was added to the precursor solution of SSCN. This resulting material was used for the photodegradation of tetracycline hydrochloride (TC-HCl) for the first time, giving improved visible light sensitivity and high stability in the photocatalytic process. This provides a new method for modifying self-sensitive carbon nitride carbon.

The treatment effect of chemotherapeutics is often impeded by nonspecific biodistribution and limited biocompatibility. Polymeric core-shell nanocarriers (PCS NCs) composed of a polymer core and at least one shell have been widely applied for cancer therapy and have shown great potential in selectively delivering chemotherapeutic drugs to tumor sites. These PCS NCs can effectively ameliorate the delivery efficiency and therapeutic index of anticarcinogens by prolonging drug residence in the bloodstream, enhancing tumor tissue drug penetration, facilitating cellular drug uptake, controlling the spatiotemporal release of payloads, or codelivering two or more bioactive agents. This review summarizes recently published literature on using PCS NCs to transport chemotherapeutic drugs with poor aqueous solubility and discusses their design principles, structural features, functional properties, and potential limitations.

Photocatalysis is one of the efficient approaches for pollution control in water. However, the traditional photocatalysts used for the removal of organic pollutants are in powder form, which makes it difficult to recover them from the suspended reaction system. On the contrary, thin film photocatalyst is easy to be retrieved and possesses unique feature for practical application. In present work, stable TiO2 sol suspension was prepared and amorphous TiO2 thin film was then immobilized upon glass substrate through facile spin coating method. The thickness of film could be simply controlled by changing the number of coatings, and anatase TiO2 film could be formed after calcination. The prepared thin films were characterized with X-ray diffraction (XRD), ultravioletvisible spectrophotometry (UV-vis), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The photodegradations of organic pollutants including colored dye and colorless antibiotic were tested and found to be thickness-dependent. Additionally, the prepared film photocatalst has good stability and may have potential applications in wastewater treatment.

Metallic 1T-phase MoS2 is a newly emerging and attractive catalyst since it has more available active sites and high carrier mobility in comparison with its widely used counterpart of semiconducting 2H-MoS2. Herein, 1T/2H-MoS2(N) (N: MoO3 nanowires were used to prepare 1T/2H-MoS2) was synthesized by using molybdenum trioxide (MoO3) nanowires as the starting material and applied in the photodegradation of antibiotic residue in water. Enhanced photocatalytic performance was observed on the obtained 1T/2H-MoS2(N), which was 2.8 and 1.3 times higher than those on 1T/2H-MoS2(P) (P: commercial MoO3 powder was used to prepare 1T/2H-MoS2) and 2H-MoS2, respectively. The active component responsible for the photodegradation was detected and a reaction mechanism is proposed.

Silicon nitride (Si 3 N 4 ) ceramic is mainly used as the catalyst support for photocatalytic application. In this paper, Si 3 N 4 nanowires (SNWs) were successfully prepared by directly nitriding Si powders and firstly applied as an efficient photocatalyst for the degradation of antibiotic residues. Comparing with commercial Si 3 N 4 powder (SNPs), the prepared SNWs demonstrate enhanced photocatalytic activity for tetracycline hydrochloride (TC-HCl) photodegradation under UV–vis light with good stability. The improved photocatalytic performance should come from its unique morphology and small size. The synthesis and application of Si 3 N 4 nanowires in removing antibiotic residue may contribute to development of newly efficient photocatalyst for environmental issues.

To develop the high-efficient visible-light photocatalyst with good recyclability is curial for its application in environment remediation. Herein, three-dimensional (3D) MoS2 nanosheet/graphene aerogel (MoS2 NS/GA) has been prepared by using 3D GA as the framework from the hydrothermal method. The prepared 3D MoS2 NS/GA is characterized and shows, even a small amount, high efficiency for photodegrading the concentrated TC-HCl. Moreover, the lost activity could be recovered by the compensation with S2− ions.

In advance oxidation processes (AOPs), modulating the activation mechanism from free radical to the non-radical pathway is the most attractive strategy for the treatment of recalcitrant pollutants. Herein, we achieved this goal after modifying the spinel CuFe2O4 catalyst by introducing non-redox metals (M = Mg, Ca, Ba, and Zn) as CuMFe2O4. The modified catalysts were evaluated for the removal of acetaminophen (ACE) using the persulfate (PS) activated system. The results revealed that the non-redox metals not only enhanced the catalytic activity of CuFe2O4 in the order of Mg > Zn > Ca > Ba but also switched the original radical pathway of CuFe2O4/PS system to the non-radical one (i.e., direct electron transfer path) of CuMgFe2O4/PS system. The critical role of non-redox metals to modulate the reaction mechanism was studied in detail using the extensive radical scavengers, EPR analysis, target pollutants selectivity, electrochemical studies, decomposition of oxidants, and identification of degradation products. Additionally, various experiments and characterizations, including XRD, EPR, H2-TPR, XPS, and FTIR, showed that the changes in the activation mechanism and catalytic activity (6–8 folds higher in the case of CuMgFe2O4) were related to the generation of a large amount of surface-bound isolated Cu2+ ions and abundant surface hydroxyl groups. The non-radical pathway of the CuMgFe2O4/PS system showed less susceptibility to the changing solution pH, excessive amount of humic acid (HA) or anions, and complete recyclability, and thus demonstrating good practical utility for wastewater. This study provides deep insight into the intrinsic role of non-redox metals to modulate both the activation mechanism and catalytic properties of the catalyst and to design new catalysts for the persulfate-based advance oxidation process.

Porous-hydrangea x%BiOBr/BiOI n-n heterojunction with ordered morphology was successfully prepared through a simple solvothermal process using Bi(NO3)3·5H2O, KBr, BiOI, and ethylene glycol as the precursors. The prepared x%BiOBr/BiOI (x = 2, 5, 10, 15 mol ratio) n-n heterojunctions exhibit enhanced photodegradation properties during treatment of tetracycline hydrochloride (TC-HCl) under visible light irradiation. The highest efficiency at optimized x = 5 is 1.3-, 1.7- and 1.3-fold higher than that of the pristine BiOI, BiOBr, and commercial titanium dioxide (P25), respectively. The improved photocatalytic performance was assigned to the optimized charge-separation properties of n-n heterojunction. However, over-loading of BiOBr upon BiOI may restrain the access of light to BiOI, which could limit the light absorption. The active species have been investigated by trapping experiments and it was found that holes (h+) and superoxide radicals (∙O2-) were mainly responsible for the photodegradation of TC-HCl. Additionally, the structure and activity relationship were systemically investigated, and the formation of n-n heterojunction is discussed accordingly. The photodegradation of TC-HCl is proved to be a complete mineralization process and the reaction mechanism is also proposed.

Graphical abstract, Highlights • A summary of key recent advances in photocatalytic removal of antibiotics in water. • Special emphasis on the strategies for improving the photodegradation efficiency. • Major challenges and critical perspectives on photocatalysis of antibiotics., Antibiotics are widely present in the environment due to their extensive and long-term use in modern medicine. The presence and dispersal of these compounds in the environment lead to the dissemination of antibiotic residues, thereby seriously threatening human and ecosystem health. Thus, the effective management of antibiotic residues in water and the practical applications of the management methods are long-term matters of contention among academics. Particularly, photocatalysis has attracted extensive interest as it enables the treatment of antibiotic residues in an eco-friendly manner. Considerable progress has been achieved in the implementation of photocatalytic treatment of antibiotic residues in the past few years. Therefore, this review provides a comprehensive overview of the recent developments on this important topic. This review primarily focuses on the application of photocatalysis as a promising solution for the efficient decomposition of antibiotic residues in water. Particular emphasis was laid on improvement and modification strategies, such as augmented light harvesting, improved charge separation, and strengthened interface interaction, all of which enable the design of powerful photocatalysts to enhance the photocatalytic removal of antibiotics.

The exploitation of green and renewable energy sources is imperative due to the environmental pollution produced by the massive use of non-renewable fossil energy. Hydrogen is a promising clean fuel since it exhibits high energy density and causes no secondary pollution. The photocatalytic production of H2 from water splitting has gained immense attention since it is a low-cost, low-energy consuming, and environmentally friendly process. Various attempts have been made to prepare active and highly efficient catalysts for photocatalytic H2 evolution. However, the use of precious metals as co-catalysts makes the H2 production costly, thus limiting their practical applications. Herein, we discuss the latest advancements in the H2 evolution on photocatalysts without noble metals. The progress achieved in the development of diverse photocatalysts has been critically evaluated in this review. Special attention has been paid to the challenges and tactics about enhancing the H2 evolution upon non-noble-metal photocatalysts. This review will be helpful for designing high efficiency photocatalysts for fundamental research and practical applications.

Graphitic carbon nitride (g-C3N4) was deposited onto TiO2 nanotube arrays (TNTAs) by a simple impregnation method to afford a Z-scheme g-C3N4/TNTAs photocatalytic system. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectrum, and X-ray photoelectron spectroscopy (XPS). The g-C3N4/TNTAs exhibit improved efficiency for photodegradation of Rh B under visible light irradiation comparing with bare TiO2 nanotube arrays, and CN(10)/TNTAs prepared by 10 times impregnation show the highest activity. The enhanced visible light photocatalytic activity is attributed to the optimized light absorption and effective separation of photogenerated electrons and holes. This article demonstrates a simple way to prepare the Z-scheme heterogeneous photocatalyst with improved performance for potential application in environmental control.

The efficient removal of antibiotic residues has drawn wide interests; however, little attention has been focused on treating them in organic system. Inorganic perovskite cesium lead bromide quantum dots were successfully prepared by anti-solvent precipitation and the prepared cesium lead bromide quantum dots were well-characterized. The photocatalytic activity was evaluated by degradation of tetracycline hydrochloride in ethanol as a model reactant under visible light for the first time. 76% tetracycline hydrochloride and 70% methyl orange were efficiently degraded in 30 min, which illustrate cesium lead bromide quantum dots could work as efficient photocatalyst for the degradation of organic pollutants in ethanol. The photoelectric conversion efficiency and photoluminescence quantum yields were measured and calculated. The photodegradation process was systematically analyzed by full-wavelength absorption. It is found that superoxide radicals may play a major role in the photocatalytic degradation process by capture experiments and the reaction mechanism has been proposed. Cesium lead bromide is not stable in water and may be converted into perovskite-related phase with water, which will result in the loss of photocatalytic activity. This work indicates that cesium lead bromide may act as an efficient photocatalyst for the removal of tetracycline hydrochloride and methyl orange in organic system, which may benefit the development/application of novel photocatalysts for special applications.

Complete exfoliation bulk MoS2 to 2D nanosheets has been efficiently achieved by the facile NaCl-assisted liquid-phase refluxing and ultrasonication exfoliation method. The obtained nanosheets have good dispersion and stability in aqueous solutions, and exhibit efficiently photocatalytic activity for removing aqueous antibiotic residues under visible light. The present work provides a new approach to achieve completely exfoliated 2D nanosheets for the photocatalytic removal of refractory pollutants.

Highly ordered TiO2 nanotube arrays (TNTAs) have been controllably prepared by anodizing Ti foils and been used as the support for co-depositing noble Au–Pt quantum dots (QDs) with good dispersion. Well dispersed Au–Pt nanoparticles around 5 nm have been simultaneously deposited on the TNTAs through a facilely simultaneous photo-irradiation-reduction method. The prepared samples have been well-characterized by SEM, TEM, XRD, XPS, UV–Vis and EC-AFM methods. The photo-degradation of Rh B under visible light (with a 420 nm cutoff) has been used as a model response to characterize the photocatalytic properties of the prepared samples; and the co-decorated Au–Pt/TNTAs show a remarkable enhancement of visible-light-driven photocatalytic properties with good stability. This shows that the co-decorated Au–Pt quantum dots could effectively utilize the visible light and suppress the recombination of electron-hole pair, although the loaded amount is ultra-low, which induces an optimized photocatalytic activity under visible light.

In skeletal muscle the activation of phosphorylase b is catalyzed by phosphorylase kinase. Both enzymes occur in vivo as part of a multienzyme complex. The two enzymes have been imaged by atomic force microscopy and the results compared to those previously found by scanning tunneling microscopy. Scanning tunneling microscopy and atomic force microscopy have been used to view complexes between the activating enzyme phosphorylase kinase and its substrate phosphorylase b. Changes in the size and shape of phosphorylase kinase were observed when it bound phosphorylase b.

Two new microscopic techniques make it possible to obtain images of biologically interesting molecules directly in air, vacuum, or under water. Scanning tunneling microscopy and atomic force microscopy both have the capacity to visualize atoms on the surface of rigid structures and provide details of molecular structure for lipids, proteins, carbohydrates, and nucleic acids. In addition to providing visualizations of individual molecules, these scanning probe techniques allow direct imaging of complexes between molecules or between molecules and higher-order subcellular structures such as membranes and cytoskeletal components. Both microscopes can be operated under a variety of ambient conditions ranging from high vacuum to above atmospheric pressure. Specimens need not be dry; both techniques have been used to image molecules in aqueous media under nearly physiological conditions. It is proposed that as these techniques mature they will allow direct observation of many molecular interactions under physiological conditions or even in vivo while they are occurring within the cell.

Scanning tunneling microscopy (STM) has been used to examine glycogen molecules. Individual molecules were approximately ellipsoidal with dimensions in the 20- to 60-nm range. Images of the glycogen molecular surfaces have a laminar appearance. The layered features seen on the surfaces of the molecules suggest that glycogen may grow from one edge as a laminar structure to form an ellipsoid rather than originating at a central point with radial growth of the oligosaccharide chains to form a sphere. The results of these studies indicate that STM can be used to determine details of polysaccharide structures.

Scanning tunneling microscopy (STM) has been used as a method of studying the relationships between the enzymes of muscle glycogenolysis. In skeletal muscles the activation of phosphorylase b is catalyzed by phosphorylase kinase. This interaction is believed to occur in vivo as part of a multienzyme complex. The molecular structures of phosphorylase b and phosphorylase kinase have been visualized by STM.1 Phosphorylase b can be seen in dimeric and tetrameric forms as well as linear and circular aggregates. Individual molecules of phosphorylase kinase image as planar, bilobate structures with a twofold axis of symmetry and a central depression. STM has also been used to visualize complexes between phosphorylase kinase and its substrate, phosphorylase b.

Scanning tunneling microscopy (STM) has been used to examine the structures of the skeletal muscle enzymes phosphorylase and phosphorylase kinase. The interaction of these two proteins represents the last step in the process of signal transduction which results in muscle glycogen being converted into metabolic energy for use in muscle contraction. Phosphorylase b has a molecular weight of 97 000 and the dimer is seen by STM to have dimensions of 11 × 5.7 nm. Phosphorylase b has a tendency to form linear arrays of dimers on the graphite surface used as the support for STM imaging. Phosphorylase kinase is imaged as a butterfly-like object with lateral dimensions of 36×27 nm. The molecular thicknesses given by scanning tunneling microscopy for these two non-conducting molecules is significantly less than expected. The height measurement in STM is dependent not only on the surface topology of the object being imaged, but also on the electronic work function of the object compared to that of the graphite surface on which it lies. In addition to the individual proteins, a complex between phosphorylase and phosphorylase kinase has been observed by scanning tunneling microscopy.

During muscle contraction, a significant part of the energy used is derived from glycogen. The rate of glucose 1-phosphate production from glycogen is determined by the fraction of glycogen phosphorylase in the phosphorylated, active, a form (Madsen, 1986). The fractions of phosphorylase in the a and b (dephospho-, inactive) forms depend on the two enzymes, phosphorylase kinase and protein phosphatase-1, which in turn are influenced by other enzymes and regulatory factors, all of which form an integrated, multienzyme glycogenolytic complex (Fig. 1) (Hallenbeck & Walsh, 1986). In this report we describe three experimental approaches to the study of regulation of this complex.

Many of the questions in biochemistry and cell biology are concerned with the relationships of proteins and other macromolecules in complex arrays which are responsible for carrying out metabolic sequences. The simplistic notion that the enzymes we isolate in soluble form from the cytoplasm were also soluble in vivo is being replaced by the concept that these enzymes occur in organized systems within the cell. In this newer view, the cytoplasm is organized and the “soluble enzymes” are in fact fixed in the cellular space and the only soluble components of the cell are small metabolites, inorganic ions etc. Further support for the concept of metabolic organization is provided by the evidence of metabolic channeling. It has been shown that for some metabolic pathways, the intermediates are not in free diffusion equilibrium with the bulk liquid in the cell but are passed along, more or less directly, from one enzyme to the next.

Though a mature process, electroless copper deposition occupies an important economic and technological position in the electronics industry today. Virtually all multilayer circuit boards require the process for through hole connections enabling the miniaturization of the board to keep apace with the total electronics trend to higher densities and smaller components. This trend places more stringent requirements on adhesion of the copper and reliability of the film. The process itself consists of two deposition stages, a surface catalyzation with a palladium colloid followed by deposition of copper. The surface presents a composite substrate of greatly different materials on which adhesion is required: copper, silicate glass, and polymeric resins of diverse compositions. To facilitate study of surface structures, we have used highly oriented pyrolitic graphite as a substrate. Scanning tunneling microscopy (STM) has shown the incipient stages of the palladium catalyst and electroless copper. The results of...

The muscle glycogenolytic complex is responsible for providing access to the reserve carbohydrate energy stores in skeletal muscle during times of vigorous exercise. The complex is a set of enzymes and regulatory factors that are bound to the carbohydrate storage polymer, glycogen. These components provide the ordered synthesis and utilization of that stored form of glucose. Glycogen and the enzyme proteins, phosphorylase and phosphorylase kinase, have been imaged by atomic force microscopy (AFM) or scanning tunneling microscopy (STM). The images of all three generally correlated well with the known features of those molecules, as measured by traditional physicochemical methods. The exception for all three polymers is that the measured height by STM is in error. In each case, the molecules appear to be only about 30% of their true thickness, as measured by height above the graphite surface. It is clear that both AFM and STM will play important roles in biomedical investigation of macromolecular structures...

ABSTRACT According to the capacitor model, the potential development of membrane electrodes is the result of adsorption of ions or charged particles on the electrode surface forming a double layer and capacitor. Our results differ from those previously reported in that the adsorption of charged particles at the pH glass electrode interface is the main cause of the suspension effect rather than the reference electrode effect. Charged particles, if adsorbed on the SCE tip opening, may cause minor suspension effects on the reference electrode potential. Our results have demonstrated how previous investigators misused the H+-form exchange resins in the suspension effect study, ignoring the exchange reaction between the H+ ion and K+ ion. The pH glass electrode, antimony electrode and lead electrode and ion exchange resin, activated carbon, graphite and silica gel were used in the study.