Processing bulk natural wood into a high-performance structural material.

Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk natural wood directly into a high-performance structural material with a more than tenfold increase in strength, toughness and ballistic resistance and with greater dimensional stability. Our two-step process involves the partial removal of lignin and hemicellulose from the natural wood via a boiling process in an aqueous mixture of NaOH and Na2SO3 followed by hot-pressing, leading to the total collapse of cell walls and the complete densification of the natural wood with highly aligned cellulose nanofibres. This strategy is shown to be universally effective for various species of wood. Our processed wood has a specific strength higher than that of most structural metals and alloys, making it a low-cost, high-performance, lightweight alternative.

[Isolation and identification of nine iridoid glycosides from Lamiophlomis rotata by HPLC combining PDA and MS].

OBJECTIVE: To establish a rapid chromatographic method to separate the iridoid glycosides from Lamioplomis rotata, and to identify the target compounds with PDA and MS. METHODS: Methanol-water gradient elution was used to separate and analyze the target compounds. The fluid fractions were gathered according to the chromatogram and dried with the nitrogen airflow. The mass fractions of the target compounds were determined with RP-HPLC and the structures were identified with PDA and MS. RESULTS: The purity of some compounds exceeded 90% and these 9 compounds were identified as iridoid glycosides, which were Phlorigidoside C (1), Schismoside (2), Sesamoside (3), Shanzhiside methylester (4), 6-O-Acetyl shanzhiside methylester (5), Phloyoside II (6), Penstemoside (7), Loganin (8) and 8-O-Acetyl shanzhiside methylester (9). CONCLUSION: The method is simple and practicable with high efficiency. It can be used to qualitative and quantitative analysis of the 9 iridoid glycosides in Lamiphlomis rotata and its preparations.

Tooth-Supported Overdentures Revisited.

The goal of prosthodontics is to provide a functional prosthesis to restore aesthetics, functions, and masticatory efficiencies. Tooth-supported overdentures are one of the treatment options for removable dentures. This article aims to discuss the advantages and disadvantages of tooth-supported overdentures and the principles of using various overdenture attachments, including non-attachment overdentures. The common treatment options in preparing the overdenture abutment are either with or without abutment coping with or without attachment systems, which were discussed and illustrated. A range of tooth-supported overdenture systems were addressed, from low to high financial implications and treatment complexities. The clinician can choose a system that best fits the patient's condition and expectations. This allows clinicians to decide and consider tooth-supported overdentures as a treatment option before full edentulism. A well-executed tooth-supported overdenture ensures the preservation of alveolar bone, optimizes patient satisfaction in denture treatment, and eventually improves the patient's adaptation when transitioning to complete dentures.

Preparation, characterization and tableting of cilnidipine solid dispersions.

Solid dispersion technique has been developed many years for improving solubility of water-insoluble drugs, aiming to achieve a better oral bioavailability. However, this technique exhibits many inconveniences when used for large-scale tableting procedures. The objective of current research work was to develop cilnidipine solid dispersions (SDs) to improve the dissolution behaviors of this water-insoluble drug. Moreover, an innovative granulation method was designed to simplify the traditional tableting technology used in solid dispersion technique. Three different kinds of polymers, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and poloxamer, were used as carriers to prepare solid dispersions. The interactions in the solid state were characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and FT-IR spectroscopy. The designed granulation method was employed to prepare solid dispersion tablets and the formulation was optimized through investigating the dissolution behaviors. The results indicated PEG solid dispersion showed the best effect both on physical characterizations and dissolution studies. Furthermore, all type of solid dispersions significantly improved the dissolution rates when compared to pure drug and its corresponding physical mixture (PM). The solid dispersion tablets prepared in simplified tableting method exhibited better operability, stability and dissolution behavior than the tablets prepared in traditional ways, which brought more opportunities to solid dispersion technique for industrial production.

COVID-19 vaccination acceptance among dental students and dental practitioners: A systematic review and meta-analysis.

BACKGROUND: Dental practitioners and dental students are classified as high-risk exposure to COVID-19 due to the nature of dental treatments, but evidence of their acceptance towards COVID-19 vaccination is still scarce. Hence, this systemic review aims to critically appraise and analyse the acceptability of COVID-19 vaccination among dental students and dental practitioners. MATERIALS AND METHODS: This review was registered in the PROSPERO database (CRD42021286108) based on PRISMA guidelines. Cross-sectional articles on the dental students' and dental practitioners' acceptance towards COVID-19 vaccine published between March 2020 to October 2021 were searched in eight online databases. The Joanna Briggs Institute critical appraisal tool was employed to analyse the risk of bias (RoB) of each article, whereas the Oxford Centre for Evidence-Based Medicine recommendation tool was used to evaluate the level of evidence. Data were analysed using the DerSimonian-Laird random effect model based on a single-arm approach. RESULTS: Ten studies were included of which three studies focused on dental students and seven studies focused on dental practitioners. Four studies were deemed to exhibit moderate RoB and the remaining showed low RoB. All the studies demonstrated Level 3 evidence. Single-arm meta-analysis revealed that dental practitioners had a high level of vaccination acceptance (81.1%) than dental students (60.5%). A substantial data heterogeneity was observed with the overall I2 ranging from 73.65% and 96.86%. Furthermore, subgroup analysis indicated that dental practitioners from the Middle East and high-income countries showed greater (p < 0.05) acceptance levels, while meta-regression showed that the sample size of each study had no bearing on the degree of data heterogeneity. CONCLUSIONS: Despite the high degree of acceptance of COVID-19 vaccination among dental practitioners, dental students still demonstrated poor acceptance. These findings highlighted that evidence-based planning with effective approaches is warranted to enhance the knowledge and eradicate vaccination hesitancy, particularly among dental students.

Cell-Penetrating Peptide-Modified Graphene Oxide Nanoparticles Loaded with Rictor siRNA for the Treatment of Triple-Negative Breast Cancer.

INTRODUCTION: Breast cancer is a malignant tumor that seriously threatens women's life and health. METHODS: In this study, we proposed to use graphene nanoparticles loaded with siRNA that can silence Rictor molecules essential for the mammalian target of rapamycin (mTOR) complex 2 (mTORC2) complex to enhance gene delivery to tumor cells through modification of cell-penetrating peptide (CPP) for the treatment of breast cancer. RESULTS: Remarkably, we successfully synthesized graphene oxide (GO)/polyethyleneimine (PEI)/polyethylene glycol (PEG)/CPP/small interfering RNA (siRNA) system, and the results were observed by atomic force microscopy (AFM) and ultraviolet visible (UV-Vis) absorption spectra. The optimum mass ratio of siRNA to GO-PEI-PEG-CPP was 1:0.5. We screened out Rictor siRNA-2 from 9 candidates, which presented the highest inhibition rate, and this siRNA was selected for the subsequent experiments. We validated that Rictor siRNA-2 significantly reduced the Rictor expression in triple negative breast cancer (TNBC) cells. Confocal fluorescence microscope and flow cytometry analysis showed that GO-PEI-PEG-CPP/siRNA was able to be effectively uptake by TNBC cells. GO-PEI-PEG-CPP/siRNA improved the effect of siRNA on the inhibition of TNBC cell viability and the induction of TNBC cell apoptosis. The expression of Rictor and the phosphorylation of Akt and p70s6k were inhibited by GO-PEI-PEG-CPP/siRNA. Tumorigenicity analysis in nude mice showed that GO-PEI-PEG-CPP/siRNA significantly repressed the tumor growth of TNBC cells in vivo. The levels of ki-67 were repressed by GO-PEI-PEG-CPP/siRNA, and the apoptosis was induced by GO-PEI-PEG-CPP/siRNA in the system. DISCUSSION: Therefore, we concluded that CPP-modified GO nanoparticles loaded with Rictor siRNA significantly repressed TNBC progression by the inhibition of PI3K/Akt/mTOR signaling. Our finding provides a promising therapeutic strategy for the treatment of TNBC.

[Study on preparation and quality standard of Xueshuantong Drop Pills].

OBJECTIVE: To optimize the best technical parameters and establish the quality standard for Xueshuantong Drop Pills. METHODS: Using moulding probability of drop pill as the evaluation to choose the best dropping condition. Using parallel experimentation for the choice of proportion of drug and matrix, and refrigerant; HPLC method was employed on ODS column which was used with a mobile phase of acetontrile-water, 0 min 20% A, 14 min 40% A, 15 min 60% A, 16 min 20% A. The wavelength of detexter was set at 203 nm. Drug-PEG4000 (1:2) was melt at 80 degrees C. Liquid-paraffin was refrigerated with 5 degrees C. Internal and external diameter of buretteare equal to 2.3 mm and 4. 8 mm. The linear ranges of notoginsenoside R1 ginsenoside, Rg1 and Rb1 were 0.51-4.08 +/- microg/mL, 3.75-30.00 microg/mL, 3.75-30.00 microg/mL, respectively. Their coefficients of determination (r) were all 0.9999. CONCLUSION: The moulding technics of drop pills have high finished product rate and good quality.

Dual pH-Responsive Hydrogel Actuator for Lipophilic Drug Delivery.

As one of the most promising drug delivery carriers, hydrogels have received considerable attention in recent years. Many previous efforts have focused on diffusion-controlled release, which allows hydrogels to load and release drugs in vitro and/or in vivo. However, it hardly applies to lipophilic drug delivery due to their poor compatibility with hydrogels. Herein, we propose a novel method for lipophilic drug release based on a dual pH-responsive hydrogel actuator. Specifically, the drug is encapsulated and can be released by a dual pH-controlled capsule switch. Inspired by the deformation mechanism of Drosera leaves, we fabricate the capsule switch with a double-layer structure that is made of two kinds of pH-responsive hydrogels. Two layers are covalently bonded together through silane coupling agents. They can bend collaboratively in a basic or acidic environment to achieve the "turn on" motion of the capsule switch. By incorporating an array of parallel elastomer stripes on one side of the hydrogel bilayer, various motions (e.g., bending, twisting, and rolling) of the hydrogel bilayer actuator were achieved. We conducted an in vitro lipophilic drug release test. The feasibility of this new drug release method is verified. We believe this dual pH-responsive actuator-controlled drug release method may shed light on the possibilities of various drug delivery systems.

Using in situ modification to enhance organic fouling resistance and rejection of pharmaceutical and personal care products in a thin-film composite nanofiltration membrane.

A commercially available nanofiltration membrane, NF90, was modified using an in situ concentration polarization-enhanced radical graft polymerization method to improve the organic fouling resistance as well as the removal of pharmaceutical and personal care products (PPCPs), including ibuprofen (IBU), carbamazepine, sulfadiazine, sulfamethoxazole, sulfamethazine, and triclosan (TRI). 3-Sulfopropyl methacrylate potassium salt (SPM) and 2-hydroxyethyl methacrylate (HEMA) were used in various dosages for surface modification, and the extent of membrane modifications was quantified based on the degree of grafting. The modified NF90 exhibited a 15-40% lower flux during humic acid (HA) fouling and 25% greater NaCl rejection compared with the virgin membrane. PPCP rejection in the modified NF90 membranes before and after HA fouling was 20-45% and 5-20% greater, respectively, compared with that of the virgin membrane. Both SPM and HEMA increased the hydrophilicity of NF90 by decreasing contact angles. Scanning electron microscopy revealed lower amounts of foulants on the modified NF90 than on the virgin membrane. The main fouling mechanism for virgin NF90 was gel layer formation and those for modified NF90 were complete and intermediate blocking. Therefore, the modification of NF90 was effective for controlling organic fouling and strongly rejecting PPCPs.

Surface Charge Density-Dependent DNA Capture through Polymer Planar Nanopores.

Surface charge density of nanopore walls plays a critical role in DNA capture in nanopore-based sensing platforms. This paper studied the effect of surface charge density on the capture of double-stranded (ds) DNA molecules into a polymer planar nanopore numerically and experimentally. First, we simulated the effective driving force ( Feff) for the translocation of a dsDNA through a planar nanopore with different sizes and surface charge densities. Focus was given on the capture stage from the nanopore mouth into the nanopore by placing a rodlike DNA at the nanopore mouth rather than inside the nanopore. For negatively charged DNA and nanopore walls, electrophoretic driving force ( FEP) under an electric field is opposed by the viscous drag force by electroosmotic flow ( FEOF). As the surface charge density of the nanopore wall becomes more negative, FEOF exceeds FEP beyond a threshold surface charge density, σthreshold, where DNA molecules cannot be driven through the nanopore via electrophoretic motion. For a 10 nm diameter nanopore filled with 1× TE buffer, σthreshold was determined to be -50 mC/m2. The simulation results were verified by performing dsDNA translocation experiments using a planar nanopore with 10 nm equivalent diameter imprinted on three polymer substrates with different surface charge densities. Both fluorescence observation and ionic current measurement confirmed that only nanopore devices with the surface charge density less negative than σthreshold allowed DNA translocation, indicating that the simulated σthreshold value can be used as a parameter to estimate the translocation of biopolymers in the design of nanopore devices.

[Research on isolation and purification of total iridoid glycosides from herbal Lamiophlomis rotata].

OBJECTIVE: Enriching the hemostatic active part total iridoid glycosides from the aqueous extract of herbal Lamiophlomis rotata. METHOD: First derivative spectrophotometry was used as the detection method and the content of total iridoid glycosides was used as tracking target. The abilities of absorption and anti-absorption of ten different types of macroreticular resin were compared, after being used to absorb the iridoid glycosides from aqueous extract of herbal L. rotata. The best purification process was optimized. RESULT: With the optimized purification process, the content of total iridoid glycosides was 67.53%. CONCLUSION: XDA-1 macroreticular resin has good ability of absorption and anti-absorption for iridoid glycosides and 50% ethanol was the best solvent for anti-absorption. The macroreticular resin could be reused.

Biological denitrification using poly(butylene succinate) as carbon source and biofilm carrier for recirculating aquaculture system effluent treatment.

Nitrate removal is essential for the sustainable operation of recirculating aquaculture system (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53 ± 0.19 kg NO3(-)-N m(-3) d(-1) (salinity, 0‰) and 0.66 ± 0.12 kg NO3(-)-Nm(-3) d(-1) (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance.