Development of thermosensitive hydrogel of Amphotericin-B and Lactoferrin combination-loaded PLGA-PEG-PEI nanoparticles for potential eradication of ocular fungal infections: In-vitro, ex-vivo and in-vivo studies.

The most prevalent conditions among ocular surgery and COVID-19 patients are fungal eye infections, which may cause inflammation and dry eye, and may cause ocular morbidity. Amphotericin-B eye drops are commonly used in the treatment of ocular fungal infections. Lactoferrin is an iron-binding glycoprotein with broad-spectrum antimicrobial activity and is used for the treatment of dry eye, conjunctivitis, and ocular inflammation. However, poor aqueous stability and excessive nasolacrimal duct draining impede these agens' efficiency. The aim of this study was to examine the effect of Amphotericin-B, as an antifungal against Candida albicans, Fusarium, and Aspergillus flavus, and Lactoferrin, as an anti-inflammatory and anti-dry eye, when co-loaded in triblock polymers PLGA-PEG-PEI nanoparticles embedded in P188-P407 ophthalmic thermosensitive gel. The nanoparticles were prepared by a double emulsion solvent evaporation method. The optimized formula showed particle size (177.0 ± 0.3 nm), poly-dispersity index (0.011 ± 0.01), zeta-potential (31.9 ± 0.3 mV), and entrapment% (90.9 ± 0.5) with improved ex-vivo pharmacokinetic parameters and ex-vivo trans-corneal penetrability, compared with drug solution. Confocal laser scanning revealed valuable penetration of fluoro-labeled nanoparticles. Irritation tests (Draize Test), Atomic force microscopy, cell culture and animal tests including histopathological analysis revealed superiority of the nanoparticles in reducing signs of inflammation and eradication of fungal infection in rabbits, without causing any damage to rabbit eyeballs. The nanoparticles exhibited favorable pharmacodynamic features with sustained release profile, and is neither cytotoxic nor irritating in-vitro or in-vivo. The developed formulation might provide a new and safe nanotechnology for treating eye problems, like inflammation and fungal infections.

Comparative evaluation of diode laser alone and in combination with desensitizing toothpaste in occlusion of dentinal tubules - A SEM study.

Background: In regular dental practice, dentinal hypersensitivity is a common oral condition affecting the adult population. Although a variety of treatment procedures are available, there is no single method that proved to be potent in eliminating dentine hypersensitivity and providing patients with complete relief. Hence the present study performed to estimate the occlusion of dentinal tubules using a diode laser alone and in combination with various desensitizing toothpaste, using the scanning electron microscope. Materials and methods: This in-vitro study consisted of five groups wherein cervical cavities were prepared on the extracted teeth followed by the application of 17% EDTA. The cavities were then treated with Novamin toothpaste, pro-arginine toothpaste, diode laser, and in combinations respectively. Then SEM analysis was done and the results obtained were statistically analyzed using tukey's multiple post hoc analysis for intra and inter group comparisons. Results: The groups which were treated with a combination of diode laser and the desensitizing agent showed statistically significant (P < 0.05) better dentinal tubule occlusion than other groups. Conclusion: The use of a diode laser has an added benefit in treating dentinal tubule occlusion when compared to desensitizing kinds of toothpaste.

Effect of nutrients deficiency on biofilm formation and single cell protein production with a purple non-sulphur bacteria enriched culture.

Purple non-sulphur bacteria (PNSB) are of interest for biorefinery applications to create biomolecules, but their production cost is expensive due to substrate and biomass separation costs. This research has utilized fuel synthesis wastewater (FSW) as a low-cost carbon-rich substrate to produce single-cell protein (SCP) and examines PNSB biofilm formation using this substrate to achieve a more efficient biomass-liquid separation. In this study, PNSB were grown in Ca, Mg, S, P, and N-deficient media using green shade as biofilm support material. Among these nutrient conditions, only N-deficient and control (nutrient-sufficient) conditions showed biofilm formation. Although total biomass growth of the control was 1.5 times that of the N-deficient condition and highest overall, the total biofilm-biomass in the N-deficient condition was 2.5 times greater than the control, comprising 49% of total biomass produced. Total protein content was similar between these four biomass samples, ranging from 35.0 ± 0.2% to 37.2 ± 0.0%. The highest protein content of 44.7 ± 1.3% occurred in the Mg-deficient condition (suspended biomass only) but suffered from a low growth rate. Overall, nutrient sufficient conditions are optimal for overall protein productivity and dominated by suspended growth, but where fixed growth systems are desired for cost-effective harvesting, N-deficient conditions provide an effective means to maximize biofilm production without sacrificing protein content.

Exploitation of bacterial strains for microplastics (LDPE) biodegradation.

Plastic waste (microplastics) is one of the primary sources of environmental pollutants, serving as a reservoir for them. In this study, previously isolated and screened polymer-degrading bacteria (B. subtilis V8, P. aminophilusB1 4-, P. putida C 2 5, P. aeruginosa V1, and A. calcoaceticus V4) were utilised to examine the biodegradation of LDPE (low-density polyethylene) microplastics. Response surface methodology (RSM) was used to optimize the physicochemical growth parameters (pH, temperature, and ammonium sulphate concentration). By using the polyphasic approach, including CO2 estimation, weight loss analysis, scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy, and electrical conductivities examine the plastic biodegradability. After four months, all biodegradable plastic samples were evaluated. When compared to the other tested cultures, P. aeruginosa V1 showed the most significant degradation (CO2evolution of 8.86 g.l-l and percentage weight loss of 18.21 %) with increased electrical conductivity, followed by B. subtilis V8 (CO2 evolution of 8.10 g.l-l and percentage weight loss of 16.12 %), A. calcoaceticus V4 (CO2 evolution of 7.21 g.l-l and percentage weight loss of 15.44 %), P. putida C 2-5 (CO2 evolution of 5.76 g.l-l and percentage weight loss of 13.30 %), and P. aminophilus B1 4- (CO2 evolution of 5.62 g.l-l and percentage weight loss of 11.72 %). The deteriorated materials' exterior modifications (surface alteration) were also examined using SEM analysis, and the chemical bonding alterations (bond vibration-bending) were determined using FT-IR spectroscopy.

Viability of Lactobacillus delbrueckii in chocolates during storage and in-vitro bioaccessibility of polyphenols and SCFAs.

This study evaluated the viability of encapsulated Lactobacillus delbrueckii subsp. bulgaricus in chocolate during storage and in-vitro gastrointestinal transit. Flavonoid contents and short chain fatty acids (SCFAs) production during gastrointestinal transit were also assessed. Encapsulated L. delbrueckii subsp. bulgaricus survived well in chocolates >7 logs both after 120 days of storage at 4 °C and 25 °C, and during in-vitro gastrointestinal transit. The release of SCFAs through in-vitro gastrointestinal digestion and colonic fermentation revealed that probiotic-chocolates could be an excellent source of nutrients for the gut microbiota. Encapsulated probiotic in chocolates with 70% cocoa produced significantly (P < 0.05) more acetic, propionic, isobutyric, butyric and isovaleric acids than that with 45% cocoa. The bioconversion results of a specific polyphenol by L. delbrueckii subsp. bulgaricus exhibited that chocolate polyphenols could be utilized by probiotics for their metabolism. These findings confirmed that chocolate could be successfully fortified with L. delbrueckii subsp. bulgaricus encapsulation to improve health promoting properties of chocolates.

New use for old drug: Local delivery of puerarin facilitates critical-size defect repair in rats by promoting angiogenesis and osteogenesis.

Objectives: Large bone defect repair is a challenging clinical problem due to limited self-repair ability. A well-designed bone filling product should possess the ability to induce tissue in-growth and facilitate neovascularization and new bone formation. Puerarin has been used in clinics for a long time, and recently it was found to be able to promote osteogenesis. This study aimed to investigate a puerarin-based drug/delivery combination implant for promoting large bone defect repair. Methods: Puerarin was incorporated into the poly (lactic-co-glycolic acid)/ß-calcium phosphate (PLGA/TCP, PT) to form a porous PLGA/TCP/Puerarin (PTP) composite scaffold by low-temperature rapid prototyping technology. Its structural and degradation were analyzed in vitro. Then we employed a rat calvarial critical size defect model to assess the potency of the PTP scaffold. MC3T3-E1 cells and EA. hy 926 â€‹cells were used to investigate the underlying mechanism. Results: PTP scaffold inherited all advantages of PT scaffold in structural, mechanical, and biodegradation, meanwhile puerarin stably and continuously released from PTP scaffold and lasted for 5 months in vitro. At 8 weeks after implantation, the PTP scaffold triggered new bone formation in the macro-pores of the scaffold and inside the scaffold accompanied by the degrading materials. The underlying mechanism revealed that the PTP scaffold induced vascular infiltration and recruit repair cells through stimulating vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) expressions to promote angiogenesis and osteogenesis. Conclusion: Puerarin-enriched porous PTP scaffold was a promising local delivery system with sustained release of puerarin for facilitating defect repair through getting synergistic angiogenic and osteogenic effects. The Translational Potential of this Article: The PTP scaffold presents a potential drug/device combination medical implant for large bone defect repair, which also provides a new and innovative application for the "old drug" puerarin.

Preparation, characterization, and antibacterial activity of plaunotol and plaunoi extracts complexed with hydroxypropyl-ß-cyclodextrin.

Croton stellatopilosus (Plaunoi) leaves accumulate several diterpenes and possess various pharmacological activities. The present study aimed to prepare, characterize and assess the antibacterial activity of inclusion complexes prepared by mixing plaunotol (PL) or plaunoi extract (PE) with cyclodextrins (CD), including α-CD, ß-CD, γ-CD, and hydroxypropyl-ß-cyclodextrin (HP-ß-CD). The inclusion complexes were characterized using SEM, XRD, DSC, and FT-IR and evaluated for aqueous solubility and thermal stability. The PL and PE lyophilized complexes with HP-ß-CD were further evaluated for their antibacterial activity against acne-causing bacteria. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of PL, PE, and the inclusion complexes evaluated using the agar dilution method revealed that the MIC and MBC values of the inclusion complexes were lower than those of PL or PE alone. Interestingly, the complexes had a synergistic activity with clindamycin after testing with checkerboard assay. The hydrogel containing the inclusion complex and clindamycin were assessed for antibacterial activity using the agar well diffusion method. The results indicated that the hydrogels showed significant inhibition of bacterial growth. In conclusion, the prepared solid dispersion of PL or PE with HP-ß-CD could enhance antibacterial activity by increasing the drug solubility. The hydrogels containing PL or PE complex and clindamycin could be considered as a candidate for the treatment of acne vulgaris.

Low-cost, open-source XYZ nanopositioner for high-precision analytical applications.

Nanoscale positioning has numerous applications in both academia and industry. A growing number of applications require devices with long working distances and nanoscale resolutions. Friction-inertia piezoelectric positioners, which are based on the stick-slip mechanism, achieve both nanometer resolution and centimeter-scale travel. However, the requirements of complex preload mechanism, precision machining, and precise assembly increase the cost of conventional friction-inertia nanopositioners. Herein we present the design of an open-source XYZ-axis nanopositioning system. Utilizing a magnet-based stick-slip driving mechanism, the proposed XYZ nanopositioner provides several advantages, including sub-nanometer resolution, a payload capacity of up to 12 kg (horizontal), compact size, low cost, and easy assembly; furthermore, the system is adjustment-free. The performance tests validate the precision of the system in both scanning and stepping operation modes. Moreover, the resonant spectra affirm the rigidity and dynamic response of the mechanism. In addition, we demonstrate the practical applications of this nanopositioner in various measurement techniques, including scanning electron microscopy, vibrometry, and atomic force microscopy. Furthermore, we present 11 variations of the nanopositioner designs that are either compatible with ultra-high-vacuum systems and other existing systems, 3D printable, or hacking commercial linear slides.

Chemo-photothermal immunotherapy for eradication of orthotopic tumors and inhibition of metastasis by intratumoral injection of polydopamine versatile hydrogels.

Cancer remains one of the leading causes of death globally and metastasis always leads to treatment failure. Here, we develop a versatile hydrogel loading photothermal agents, chemotherapeutics, and immune-adjuvants to eradicate orthotopic tumors and inhibit metastasis by combinational therapy. Hydrogel networks were synthesized via the thiol-Michael addition of polydopamine (PDA) with thiolated hyaluronic acid. PDA acted as a cross-linking agent and endowed the hydrogel with excellent photothermal property. Meanwhile, a chemotherapeutic agent, doxorubicin (DOX), was loaded in the hydrogel via π‒π stacking with PDA and an immune-adjuvant, CpG-ODN, was loaded via electrostatic interaction. The release of DOX from the hydrogel was initially slow but accelerated due to near infrared light irradiation. The hydrogels showed remarkably synergistic effect against 4T1 cancer cells and stimulated plenty of cytokines secreting from RAW264.7 cells. Moreover, the hydrogels eradicated orthotopic murine breast cancer xenografts and strongly inhibited metastasis after intratumoral injection and light irradiation. The high anticancer efficiency of this chemo-photothermal immunotherapy resulted from the strong synergistic effect of the versatile hydrogels, including the evoked host immune response. The combinational strategy of chemo-photothermal immunotherapy is promising for highly effective treatment of breast cancer.

Anti-biofilm potential of Lactobacillus plantarum Y3 culture and its cell-free supernatant against multidrug-resistant uropathogen Escherichia coli U12.

Uropathogens develop biofilms on urinary catheters, resulting in persistent and chronic infections that are associated with resistance to antimicrobial therapy. Therefore, the current study was performed to control biofilm-associated urinary tract infections through assaying the anti-biofilm ability of lactic acid bacteria (LAB) against multidrug-resistant (MDR) uropathogens. Twenty LAB were obtained from pickles and fermented dairy products, and screened for their anti-biofilm and antimicrobial effects against MDR Escherichia coli U12 (ECU12). Lactobacillus plantarum Y3 (LPY3) (MT498405), showed the highest inhibitory effect and biofilm production. Pre-coating of a microtitre plate with LPY3 culture was more potent than co-incubation. Pre-coating with LPY3 culture generated a higher anti-biofilm effect with an adherence of 14.5% than cell free supernatant (CFS) (31.2%). Anti-biofilm effect of CFS was heat stable up to 100 °C with higher effect at pH 4-6. Pre-coating urinary catheter with LPY3 culture reduced the CFU/cm2 of ECU12 attached to the catheter for up to seven days. Meanwhile, CFS reduced the ECU12 CFU/cm2 for up to four days. Scanning electron microscope confirmed the reduction of ECU12 adherence to catheters after treatment with CFS. Therefore, Lactobacillus plantarum can be applied in medical devices as prophylactic agent and as a natural biointervention to treat urinary tract infections.

Critical roles of FGF, RA, and WNT signalling in the development of the human otic placode and subsequent lineages in a dish.

Introduction: Efficient induction of the otic placode, the developmental origin of the inner ear from human pluripotent stem cells (hPSCs), provides a robust platform for otic development and sensorineural hearing loss modelling. Nevertheless, there remains a limited capacity of otic lineage specification from hPSCs by stepwise differentiation methods, since the critical factors for successful otic cell differentiation have not been thoroughly investigated. In this study, we developed a novel differentiation system involving the use of a three-dimensional (3D) floating culture with signalling factors for generating otic cell lineages via stepwise differentiation of hPSCs. Methods: We differentiated hPSCs into preplacodal cells under a two-dimensional (2D) monolayer culture. Then, we transferred the induced preplacodal cells into a 3D floating culture under the control of the fibroblast growth factor (FGF), bone morphogenetic protein (BMP), retinoic acid (RA) and WNT signalling pathways. We evaluated the characteristics of the induced cells using immunocytochemistry, quantitative PCR (qPCR), population averaging, and single-cell RNA-seq (RNA-seq) analysis. We further investigated the methods for differentiating otic progenitors towards hair cells by overexpression of defined transcription factors. Results: We demonstrated that hPSC-derived preplacodal cells acquired the potential to differentiate into posterior placodal cells in 3D floating culture with FGF2 and RA. Subsequent activation of WNT signalling induced otic placodal cell formation. By single-cell RNA-seq (scRNA-seq) analysis, we identified multiple clusters of otic placode- and otocyst marker-positive cells in the induced spheres. Moreover, the induced otic cells showed the potential to generate hair cell-like cells by overexpression of the transcription factors ATOH1, POU4F3 and GFI1. Conclusions: We demonstrated the critical role of FGF2, RA and WNT signalling in a 3D environment for the in vitro differentiation of otic lineage cells from hPSCs. The induced otic cells had the capacity to differentiate into inner ear hair cells with stereociliary bundles and tip link-like structures. The protocol will be useful for in vitro disease modelling of sensorineural hearing loss and human inner ear development and thus contribute to drug screening and stem cell-based regenerative medicine.

Coating-thickness-dependent physical properties and cutting temperature for cutting Inconel 718 with TiAlN coated tools.

Introduction: Coating-thickness-dependent physical properties can induce different cutting temperatures with physical vapor deposition (PVD) titanium aluminum nitride (TiAlN) ceramic-coated tools. The determination of the optimal TiAlN coating thickness is important to obtain superior coating physical properties and decrease the cutting temperature of Inconel 718 alloy. Objectives: The present study investigates the effects of coating thickness on the physical properties of TiAlN coatings and the cutting temperature during the machining of Inconel 718 alloy. The optimal coating thickness is also determined. Methods: First, the direct-current-arc method was utilized to deposit PVD Ti0.55Al0.45N coatings with thickness of 1.6 µm, 2 µm, 2.5 µm, and 3 µm, onto a cemented carbide substrate. Second, the coating-thickness-dependent physical properties were characterized and estimated with a radar chart. Third, the effects of coating thickness on coating antifriction were analyzed with the tool-chip friction coefficient when cutting Inconel 718 with PVD TiAlN coated tools. Both the maximum cutting temperature generated in the chip and the cutting temperature of the tool bodies were measured for analyzation of the thermal barrier effect of coating. Finally, the topographies of the deformed chip and tool-chip contact area were obtained and investigated to determine the effects of coating thickness on the cutting temperature. Results: The tool-chip friction coefficient and coating thermal barrier effect were affected by the coating thickness. Ti0.55Al0.45N coated tools with moderate coating thickness had fine antifriction effect with Inconel 718. The thermal barrier effect of Ti0.55Al0.45N coating was positively related to the coating thickness. Conclusions: The optimal TiAlN coating thickness was determined as 2 µm, which resulted in superior physical properties and reduced the cutting temperature of Inconel 718.

Bone infection site targeting nanoparticle-antibiotics delivery vehicle to enhance treatment efficacy of orthopedic implant related infection.

Orthopedic implants account for 99% of orthopedic surgeries, however, orthopedic implant-related infection is one of the most serious complications owing to the potential for limb-threatening sequelae and mortality. Current antibiotic treatments still lack the capacity to target bone infection sites, thereby resulting in unsatisfactory therapeutic effects. Here, the bone infection site targeting efficacy of D6 and UBI29-41 peptides was investigated, and bone-and-bacteria dual-targeted nanoparticles (NPs) with D6 and UBI29-41 peptides were first fabricated to target bone infection site and control the release of vancomycin in bone infection site. The results of this study demonstrated that the bone-and-bacteria dual-targeted mesoporous silica NPs exhibit excellent bone and bacteria targeting efficacy, excellent biocompatibility and effective antibacterial properties in vitro. Furthermore, in a rat model of orthopedic implant-related infection with methicillin-resistant Staphylococcus aureus, the growth of bacteria was evidently inhibited without cytotoxicity, thus realizing the early treatment of implant-related infection. Hence, the bone-and-bacteria dual-targeted molecule-modified NPs may target bacteria-infected bone sites and act as ideal candidates for the therapy of orthopedic implant-related infections.

A hydrogel spinal dural patch with potential anti-inflammatory, pain relieving and antibacterial effects.

CSFL caused by spinal dural defect is a common complication of spinal surgery, which need repair such as suture or sealants. However, low intracranial pressure symptoms, wound infection and prolonged hospital associated with pin-hole leakage or loose seal effect were often occurred after surgical suture or sealants repair. Stable, pressure resistance and high viscosity spinal dural repair patch in wet environment without suture or sealants was highly needed. Herein, a bioactive patch composed of alginate and polyacrylamide hydrogel matrix cross-linked by calcium ions, and chitosan adhesive was proposed. This fabricated patch exhibits the capabilities of promoting defect closure and good tight seal ability with the bursting pressure is more than 790 mm H2O in wet environment. In addition, the chitosan adhesive layer of the patch could inhibit the growth of bacterial in vitro, which is meaningful for the postoperative infection. Furthermore, the patch also significantly reduced the expression of GFAP, IBA-1, MBP, TNF-α, and COX-2 in early postoperative period in vivo study, exerting the effects of anti-inflammatory, analgesic and adhesion prevention. Thus, the bioactive patch expected to be applied in spinal dural repair with the good properties of withstanding high pressure, promoting defect closure and inhibiting postoperative infection.

Long-term safety and absorption assessment of a novel bioresorbable nitrided iron scaffold in porcine coronary artery.

This study aimed to investigate the long-term biocompatibility, safety, and degradation of the ultrathin nitrided iron bioresorbable scaffold (BRS) in vivo, encompassing the whole process of bioresorption in porcine coronary arteries. Fifty-two nitrided iron scaffolds (strut thickness of 70 µm) and 28 Vision Co-Cr stents were randomly implanted into coronary arteries of healthy mini-swine. The efficacy and safety of the nitrided iron scaffold were comparable with those of the Vision stentwithin 52 weeks after implantation. In addition, the long-term biocompatibility, safety, and bioresorption of the nitrided iron scaffold were evaluated by coronary angiography, optical coherence tomography, micro-computed tomography, scanning electron microscopy, energy dispersive spectrometry and histopathological evaluations at 4, 12, 26, 52 weeks and even at 7 years after implantation. In particular, a large number of struts were almost completely absorbed in situ at 7 years follow-up, which were first illustrated in this study. The lymphatic drainage pathway might serve as the potential clearance way of iron and its corrosion products.

Periosteum and development of the tissue-engineered periosteum for guided bone regeneration.

BACKGROUND: Periosteum plays a significant role in bone formation and regeneration by storing progenitor cells, and also acts as a source of local growth factors and a scaffold for recruiting cells and other growth factors. Recently, tissue-engineered periosteum has been studied extensively and shown to be important for osteogenesis and chondrogenesis. Using biomimetic methods for artificial periosteum synthesis, membranous tissues with similar function and structure to native periosteum are produced that significantly improve the efficacy of bone grafting and scaffold engineering, and can serve as direct replacements for native periosteum. Many problems involving bone defects can be solved by preparation of idealized periosteum from materials with different properties using various techniques. METHODS: This review summarizes the significance of periosteum for osteogenesis and chondrogenesis from the aspects of periosteum tissue structure, osteogenesis performance, clinical application, and development of periosteum tissue engineering. The advantages and disadvantages of different tissue engineering methods are also summarized. RESULTS: The fast-developing field of periosteum tissue engineering is aimed toward synthesis of bionic periosteum that can ensure or accelerate the repair of bone defects. Artificial periosteum materials can be similar to natural periosteum in both structure and function, and have good therapeutic potential. Induction of periosteum tissue regeneration and bone regeneration by biomimetic periosteum is the ideal process for bone repair. CONCLUSIONS: Periosteum is essential for bone formation and regeneration, and it is indispensable in bone repair. Achieving personalized structure and composition in the construction of tissue engineering periosteum is in accordance with the design concept of both universality and emphasis on individual differences and ensures the combination of commonness and individuality, which are expected to meet the clinical needs of bone repair more effectively. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: To better understand the role of periosteum in bone repair, clarify the present research situation of periosteum and tissue engineering periosteum, and determine the development and optimization direction of tissue engineering periosteum in the future. It is hoped that periosteum tissue engineering will play a greater role in meeting the clinical needs of bone repair in the future, and makes it possible to achieve optimization of bone tissue therapy.

Does dentine mineral change with anatomical location, microscopic site and patient age?

OBJECTIVE: To determine the effect of patient age (young or mature), anatomical location (shallow/deep and central/peripheral) and microscopic site (intertubular/peritubular) on dentine mineral density, distribution and composition. METHODS: Extracted posterior teeth from young (aged 19-20 years, N = 4) and mature (aged 54-77 years, N = 4) subjects were prepared to shallow and deep slices. The dentine surface elemental composition was investigated in a SEM using Backscattered Electron (BSE) micrographs, Energy Dispersive X-ray Spectroscopy, and Integrated Mineral Analysis. Qualitative comparisons and quantitative measures using machine learning were used to analyse the BSE images. Quantitative outcomes were compared using quantile or linear regression models with bootstrapping to account for the multiple measures per sample. Subsequently, a Xenon Plasma Focussed Ion Beam Scanning Electron Microscopy (Xe PFIB-SEM) was used to mill large area (100 µm) cross-sections to investigate morphology through the dentine tubules using high resolution secondary electron micrographs. RESULTS: With age, dentine mineral composition remains stable, but density changes with anatomical location and microscopic site. Microscopically, accessory tubules spread into intertubular dentine (ITD) from the main tubule lumens. Within the lumens, mineral deposits form calcospherites in the young that eventually coalesce in mature tubules and branches. The mineral occlusion in mature dentine increases overall ITD density to reflect peritubular dentine (PTD) infiltrate. The ITD observed in micrographs remained consistent for age and observation plane to suggest tubule deposition affects overall dentine density. Mineral density depends on the relative distribution of PTD to ITD that varies with anatomical location. SIGNIFICANCE: Adhesive materials may interact differently within a tooth as well as in different age groups.

A real-time and modular approach for quick detection and mechanism exploration of DPIs with different carrier particle sizes.

Dry powder inhalers (DPIs) had been widely used in lung diseases on account of direct pulmonary delivery, good drug stability and satisfactory patient compliance. However, an indistinct understanding of pulmonary delivery processes (PDPs) hindered the development of DPIs. Most current evaluation methods explored the PDPs with over-simplified models, leading to uncompleted investigations of the whole or partial PDPs. In the present research, an innovative modular process analysis platform (MPAP) was applied to investigate the detailed mechanisms of each PDP of DPIs with different carrier particle sizes (CPS). The MPAP was composed of a laser particle size analyzer, an inhaler device, an artificial throat and a pre-separator, to investigate the fluidization and dispersion, transportation, detachment and deposition process of DPIs. The release profiles of drug, drug aggregation and carrier were monitored in real-time. The influence of CPS on PDPs and corresponding mechanisms were explored. The powder properties of the carriers were investigated by the optical profiler and Freeman Technology four powder rheometer. The next generation impactor was employed to explore the aerosolization performance of DPIs. The novel MPAP was successfully applied in exploring the comprehensive mechanism of PDPs, which had enormous potential to be used to investigate and develop DPIs.

Study on RNAi-based herbicide for Mikania micrantha.

The invasive plant Mikania micrantha Kunth (M. micrantha) from South America poses a significant threat to the stability and biodiversity of ecosystems. However, an effective and economical method to control M. micrantha is still lacking. RNA interference (RNAi) has been widely studied and applied in agriculture for trait improvement. Spray-induced gene silencing (SIGS) can produce RNAi silencing effects without introducing heritable modifications to the plant genome and is becoming a novel nontransformation strategy for plant protection. In this study, the genes encoding chlorophyll a/b-binding proteins were selected as targets of RNAi, based on high-throughput sequencing of M. micrantha transcriptome and bioinformatic analyses of sequence specificity. Three types of RNAi molecules, double-stranded RNA, RNAi nanomicrosphere, and short hairpin RNA (shRNA), with their corresponding short interfering RNA sequences were designed and synthesized for SIGS vector construction, from which each RNAi molecule was transcribed and extracted to be sprayed on M. micrantha leaves. Whereas water-treated control leaves remained green, leaves treated with RNAi molecules turned yellow and eventually wilted. Quantitative real-time PCR showed that the expression levels of target genes were significantly reduced in the RNAi-treated groups compared with those of the control, suggesting that all three types of RNAi herbicides effectively silenced the endogenous target genes, which are essential for the growth of M. micrantha. We also found that shRNA showed better silencing efficiency than the other two molecules. Taken together, our study successfully designed three types of RNAi-based herbicides that specifically silenced endogenous target genes and controlled the growth of M. micrantha. Moreover, we identified a gene family encoding chlorophyll a/b-binding proteins that is important for the growth and development of M. micrantha and could serve as potential targets for controlling the spread of M. micrantha.

Compression of amorphous solid dispersions prepared by hot-melt extrusion, spray drying and vacuum drum drying.

The present study explored vacuum drum drying (VDD) as an alternative technology for amorphous solid dispersions (ASDs) manufacture compared to hot-melt extrusion (HME) and spray drying (SD) focusing on downstream processability (powder properties, compression behavior and tablet performance). Ritonavir (15% w/w) in a copovidone/sorbitan monolaurate matrix was used as ASD model system. The pure ASDs and respective tablet blends (TB) (addition of filler, glidant, lubricant) were investigated. Milled extrudate showed superior powder properties (e.g., flowability, bulk density) compared to VDD and SD, which could be compensated by the addition of 12.9% outer phase. Advantageously, the VDD intermediate was directly compressible, whereas the SD material was not, resulting in tablets with defects based on a high degree of elastic recovery. Compared to HME, the VDD material showed superior tabletability when formulated as TB, resulting in stronger compacts at even lower solid fraction values. Despite the differences in tablet processing, tablets showed similar tablet performance in terms of disintegration and dissolution independent of the ASD origin. In conclusion, VDD is a valid alternative to manufacture ASDs. VDD offered advantageous downstream processability compared to SD: less solvents and process steps required (no second drying), improved powder properties and suitable for direct compression.