Modeling Ion Transport across Thin-Film Composite Membranes During Saltwater Electrolysis.

Affordable thin-film composite (TFC) membranes are a potential alternative to more expensive ion exchange membranes in saltwater electrolyzers used for hydrogen gas production. We used a solution-friction transport model to study how the induced potential gradient controls ion transport across the polyamide (PA) active layer and support layers of TFC membranes during electrolysis. The set of parameters was simplified by assigning the same size-related partition and friction coefficients for all salt ions through the membrane active layer. The model was fit to experimental ion transport data from saltwater electrolysis with 600 mM electrolytes at a current density of 10 mA cm-2. When the electrolyte concentration and current density were increased, the transport of major charge carriers was successfully predicted by the model. Ion transport calculated using the model only minimally changed when the negative active layer charge density was varied from 0 to 600 mM, indicating active layer charge was not largely responsible for controlling ion crossover during electrolysis. Based on model simulations, a sharp pH gradient was predicted to occur within the supporting layer of the membrane. These results can help guide membrane design and operation conditions in water electrolyzers using TFC membranes.

Spatio-temporal variation of bacterial community structure in two intertidal sediment types of Jiaozhou Bay.

The intertidal sediment environment is dynamic and the biofilm bacterial community within it must constantly adapt, but an understanding of the differences in the biofilm bacterial community within sediments of different types is still relatively limited. The semi-enclosed Jiaozhou Bay has a temperate monsoon climate, with strong currents at the mouth of the bay. In this study, the structure of the bacterial community in Jiaozhou Bay sediment biofilms are described using high-throughput 16 S rRNA gene sequencing and the effects of temporal change and different sediment environment types are discussed. Alpha diversity was significantly higher in sandy samples than in muddy samples. Sandy sediments with increased heterogeneity promote bacterial aggregation. Beta diversity analysis showed significant differences between sediment types and between stations. Proteobacteria and Acidobacteria were significantly more abundant at ZQ, while Campilobacterota was significantly more abundant at LC. The relative abundances of Bacteroidetes, Campilobacterota, Firmicutes, and Chloroflexi were significantly higher in the muddy samples, while Actinobacteria and Proteobacteria were higher in the sandy samples. There were different phylum-level biomarkers between sediment types at different stations. There were also different patterns of functional enrichment in biogeochemical cycles between sediment types and stations with the former having more gene families that differed significantly, highlighting their greater role in determining bacterial function. Bacterial amplicon sequence variant variation between months was less than KEGG ortholog variation between months, presumably the temporal change had an impact on shaping the intertidal sediment bacterial community, although this was less clear at the gene family level. Random forest prediction yielded a combination of 43 family-level features that responded well to temporal change, reflecting the influence of temporal change on sediment biofilm bacteria.

3D Visualization and Augmented Reality for Orthopedics.

Augmented reality (AR) techniques play an important role in the field of minimally invasive surgery for orthopedics. AR can improve the hand-eye coordination by providing surgeons with the merged surgical scene, which enables surgeons to perform surgical operations more easily. To display the navigation information in the AR scene, medical image processing and three-dimensional (3D) visualization of the important anatomical structures are required. As a promising 3D display technique, integral videography (IV) can produce an autostereoscopic image with full parallax and continuous viewing points. Moreover, IV-based 3D AR navigation technique is proposed to present intuitive scene and has been applied in orthopedics, including oral surgery and spine surgery. The accurate patient-image registration, as well as the real-time target tracking for surgical tools and the patient, can be achieved. This paper overviews IV-based AR navigation and the applications in orthopedics, discusses the infrastructure required for successful implementation of IV-based approaches, and outlines the challenges that must be overcome for IV-based AR navigation to advance further development.

Integrated production of xylose and docosahexaenoic acid from hemicellulose and cellulose in corncob.

Exploring efficient and comprehensive utilization of agricultural waste to produce high value-added products has been global research hotspot. In this study, a novel process for integrated production of xylose and docosahexaenoic acid (DHA) from hemicellulose and cellulose in corncob was developed. Corncob was treated with dilute H2SO4 at 121 °C for 1 h and xylose was readily produced with a recovery yield of 79.35 %. The corncob residue was then subject to alkali pretreatment under optimized conditions of 0.1 g NaOH/g dry solid, 60 °C for 2 h, and the contents of cellulose, hemicellulose, and lignin in the resulting residue were 87.49 %, 7.58 % and 2.31 %, respectively. The cellulose in the residue was easily hydrolyzed by cellulase, yielding 74.87 g/L glucose with hydrolysis efficiency of 77.02 %. Remarkably, the corncob residue hydrolysate supported cell growth and DHA production in Schizochytrium sp. ATCC 20888 well, and the maximum biomass of 32.71 g/L and DHA yield of 4.63 g/L were obtained, with DHA percentage in total fatty acids of 36.89 %. This study demonstrates that the corncob residue generated during xylose production, rich in cellulose, can be effectively utilized for DHA production by Schizochytrium sp., offering a cost-effective and sustainable alternative to pure glucose.

Photobiomodulation therapy enhances neural differentiation of dental pulp stem cells via ERK1/2 signaling pathway.

Photobiomodulation therapy (PBMT) is the application of a low-level laser device to generate physiological changes and provide therapeutic effects. Till now, the effects of PBMT on the neural differentiation of mesenchymal stem cells have been rarely reported. Herein, the potential effect and mechanism of PBMT on the neural differentiation of dental pulp stem cells (DPSCs) were preliminarily investigated in our research. The optimal dose of 3.75 J/cm2 was first screened for use in the following neural-inducing studies. Then, DPSCs were cultured in neural induction medium and treated with laser irradiation for 7 days. From the results of morphology and immunofluorescence, we found that irradiation promoted the formation of neural stem cell-like spheroids derived from DPSCs and enhanced potential neural differentiation. Furthermore, neural differentiation gene expressions of Nestin, microtubule-associated protein-2, and neural cell adhesion molecule were increased after PBMT irradiation. The protein expressions of class III ß-tubulin and neurogenic differentiation factor 1 were also improved. Meanwhile, the involvement of extracellular signal-regulated kinase (ERK1/2) was investigated by western blot. Our study showed that the neural differentiation of DPSCs was promoted by PBMT, and the underlying mechanism in this process was associated with activating the ERK1/2 signaling pathway.

An accurate 3D augmented reality navigation system with enhanced autostereoscopic display for oral and maxillofacial surgery.

BACKGROUND: Oral and maxillofacial surgery demands high precision navigation to achieve optimal surgical outcomes. Augmented reality (AR) has been a promising solution for intuitive and accurate guidance, whereas existing systems have room for improvement. METHODS: We propose a high quality and accurate in situ AR navigation system. Enhanced image quality is achieved by deploying eye tracking in lenticular-based autostereoscopic display. Viewpoint tracking and optical tracking are integrated to assure accurate in situ images. RESULTS: The proposed system can provide in situ AR images in real-time, with a viewing angle of 59.5° × 49.1°, 3D image resolution of 0.35 × 0.21 mm, and image accuracy of 0.99 ± 0.70 mm. A maxillary drilling experiment obtains average position error of 1.12 ± 0.30 mm and localization time of 8.7 ± 3.9 s, significantly better than conventional 2D navigation system. CONCLUSIONS: The proposed system can display high-quality AR images and therefore reduce positioning error and operating time.

Molecular packing of high-mobility diketo pyrrolo-pyrrole polymer semiconductors with branched alkyl side chains.

We describe a series of highly soluble diketo pyrrolo-pyrrole (DPP)-bithiophene copolymers exhibiting field effect hole mobilities up to 0.74 cm(2) V(-1) s(-1), with a common synthetic motif of bulky 2-octyldodecyl side groups on the conjugated backbone. Spectroscopy, diffraction, and microscopy measurements reveal a transition in molecular packing behavior from a preferentially edge-on orientation of the conjugated plane to a preferentially face-on orientation as the attachment density of the side chains increases. Thermal annealing generally reduces both the face-on population and the misoriented edge-on domains. The highest hole mobilities of this series were obtained from edge-on molecular packing and in-plane liquid-crystalline texture, but films with a bimodal orientation distribution and no discernible in-plane texture exhibited surprisingly comparable mobilities. The high hole mobility may therefore arise from the molecular packing feature common to the entire polymer series: backbones that are strictly oriented parallel to the substrate plane and coplanar with other backbones in the same layer.

Formulation of sustained-release microspheres of granulocyte macrophage colony stimulating factor by freezing-induced phase separation with dextran and encapsulation with blended polymers.

This study aimed to assess the potential merits of formulating sustained-release microspheres of recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) via freezing-induced phase separation (FIPS) of the protein with dextran followed by encapsulation with binary mixture of poly(lactic-co-glycolic acid) (PLGA) 2A (MW∼12K) and 3A (MW∼47K) or of PLGA2A and polylactic acid (PLA; MW∼83K). The formulated dextran particles and microspheres were characterized in vitro for loading, aggregation, bioactivity and release behavior of the protein where appropriate. rhGM-CSF retained about 60% of bioactivity with no significant aggregation after each formulation step. Encapsulation of protein-loaded dextran particles attained only 80% with the PLGA2A and PLGA3A blend, but 100% with the PLGA2A and PLA mixture. The former formulation exhibited a triphasic in-vitro release profile typical of PLGA microspheres while the latter revealed a much lower initial burst followed by a steady and complete release of rhGM-CSF with preserved bioactivity over a 15-day period.

Physical stability and in vivo brain delivery of polymeric ibuprofen nanoparticles fabricated by flash nanoprecipitation.

Ibuprofen (IBP), a common non-steroidal anti-inflammatory drug (NSAID) with a log P of 3.51, has been shown to possess potential benefit in the treatment of Alzheimer's disease. However, the bioavailability of IBP to the brain is poor, which can be linked to its extensive binding to plasma proteins in the blood. This study aimed to evaluate the nanoparticle production of IBP by flash nanoprecipitation (FNP) technology, and to determine whether the nanoparticles prepared by FNP could enhance the delivery of IBP into the brain. Polymeric IBP nanoparticles were prepared with poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) diblock copolymer as stabilizer under optimized conditions using a four-stream multi-inlet vortex mixer (MIVM). The optimized nanoparticles displayed a mean particle size of around 50 nm, polydispersity index of around 0.2, drug loading of up to 30% and physical stability of up to 34 days. In-depth surface characterization using zeta potential measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) showed that the surfaces of these nanoparticles were covered with the hydrophilic PEG groups from the diblock copolymer. In vivo brain uptake study of the IBP nanoparticles indicated that the particles, when coated with polysorbate 80, displayed an enhanced brain uptake. However, the extent of brain uptake enhancement appeared limited, possibly due to a rapid release of IBP from the nanoparticles into the blood stream following intravenous administration.

Size controlled fabrication of enzyme encapsulated amorphous calcium phosphate nanoparticle and its intracellular biosensing application.

Inorganic-enzyme composites have been widely used for applications in catalysis and analytical science. Amorphous calcium phosphate, as a biocompatible material, can form open hydrated structure to encapsulate and protect enzymes. So far, there have been few progress on size-adjustable amorphous calcium phosphate nanoparticles since the diameter controllability is limited by its natural aggregation characteristics. By co-precipitation and nano-channel extrusion, we developed enzyme-loaded amorphous calcium phosphate nanoparticles with adjustable diameters. These enzyme-loaded particles showed high thermal and chemical stability as well as biocompatibility. The nano-sized enzyme-loaded particles can further expand their application fields and be used as intracellular enzyme probes. Delivering glucose oxidase enzyme by amorphous calcium phosphate nanoparticles enables fluorescent monitoring of glucose levels in living cells, which can be used to study the metabolism rates of cancer cells and normal cells. The nano-channel extrusion method can also be used as a template to encapsulate different kinds of enzymes to expand catalysis and biosensing applications.

Bioinspired Free-Standing One-Dimensional Photonic Crystals with Janus Wettability for Water Quality Monitoring.

Materials with specific wettability properties have aroused enormous interest and research for their broad application prospects in chemical reaction, medical diagnosis, biological analysis, etc. Here, inspired by the unique Janus wettability of lotus leaf and Bragg stacks of beetles, we present a free-standing film with Janus wettability and tunable structural color for water quality monitoring. This film is constructed by using a flexible polymer polyurethane (PU) to pack poly(N-isopropyl acrylamide-bis-acrylamide-acrylic acid) (P(NiPAAm-bis-AA))/TiO2 one-dimensional photonic crystals (1DPCs) into a free-standing state with Janus wettability and tunable structural color. The outer top surface of the film could achieve vivid structural color and a superhydrophobic ability; meanwhile, the outer lower surface could achieve a superhydrophilic ability. Owing to the outstanding pH-sensitive property of the P(NiPAAm-bis-AA), the Janus films could switch its structural color under different pH conditions. This imparts the free-standing film with stability and an antirotation property on the air-water interface. Based on this phenomenon, we have demonstrated a Janus wettability film, together with tunable structural color for water quality monitoring, which gives the bioinspired materials high potential applications in environmental protection.

Mussel-Inspired Polydopamine Coating: A General Strategy To Enhance Osteogenic Differentiation and Osseointegration for Diverse Implants.

Surface modifications play an important role in endowing implant surface with excellent biocompatibility and bioactivity. Among the bioinspired surface modifications, the mussel-inspired polydopamine (PDA) has aroused great interest of researchers. Herein, we fabricated PDA on diverse implant surfaces, including biopolymer, biometal, and bioceramic. Then the effects of PDA coating on cell responsive behaviors in vitro and bone formation capacity in vivo were evaluated in detail. The results showed that PDA coating was fabricated on diverse samples surface successfully, which could significantly improve the hydrophilicity of different material surfaces. Furthermore, the results indicated that PDA coating exerted direct enhancing on the adhesion, proliferation and osteogenic differentiation of bone marrow derived mesenchymal stromal cells (BMSCs) through FAK and p38 signaling pathways. During the process, the focal adhesion protein expression and osteogenic-related genes expression level (e.g., ALP, BMP2, BSP, and OPN) were considerably upregulated. Most importantly, the in vivo study confirmed that PDA coating remarkably accelerated new bone formation and enhanced osseointegration performance. Our study uncovered the biological responses stimulated by PDA coating to make a better understanding of cell/tissue-PDA interactions and affirmed that PDA, a bioinspired polymer, has great potential as a candidate and functional bioactive coating medium in bone regeneration and orthopedic application.

Augmented reality surgical navigation with accurate CBCT-patient registration for dental implant placement.

It is challenging to achieve high implant accuracy in dental implant placement, because high risk tissues need to be avoided. In this study, we present an augmented reality (AR) surgical navigation with an accurate cone beam computed tomography (CBCT)-patient registration method to provide clinically desired dental implant accuracy. A registration device is used for registration between preoperative data and patient outside the patient's mouth. After registration, the registration device is worn on the patient's teeth for tracking the patient. Naked-eye 3D images of the planning path and the mandibular nerve are superimposed onto the patient in situ to form an AR scene. Simultaneously, a 3D image of the drill is overlaid accurately on the real one to guide the implant procedure. Finally, implant accuracy is evaluated postoperatively. A model experiment was performed by an experienced dentist. Totally, ten parallel pins were inserted into five 3D-printed mandible models guided by our AR navigation method and through the dentist's experience, respectively. AR-guided dental implant placement showed better results than the dentist's experience (mean target error = 1.25 mm vs. 1.63 mm; mean angle error = 4.03° vs. 6.10°). Experimental results indicate that the proposed method is expected to be applied in the clinic. Graphical abstract ᅟ.

Amorphous carbon modification on implant surface: a general strategy to enhance osteogenic differentiation for diverse biomaterials via FAK/ERK1/2 signaling pathways.

Bone implants play a crucial role in bone repairing. Nevertheless, low capability of osteoinductivity and osteogenic differentiation for bone regeneration are disadvantages of bone implants. Therefore, it is imperative to develop a general and facile technology to promote the bioactivity of existing implants. Herein, a facile amorphous carbon-coating approach was developed to stimulate osteogenesis on diverse biomaterials, including bioceramics, biometals, and biopolymers via magnetron sputtering deposition. The results confirmed that the amorphous carbon-coating-modified surfaces could significantly enhance osteogenesis of bone marrow mesenchymal stem cells (BMSCs) on every kind of biomaterial surface. Furthermore, it was demonstrated that the FAK/ERK1/2 signaling pathways were involved in the osteogenic effects of this amorphous carbon coating. The bone regeneration ability using the calvarial bone defect model of rats confirmed that the amorphous carbon coating induced faster bone formation and mineralization, which suggested the effect of amorphous carbon coating on stimulating osteogenesis in vivo. These results suggest that the approach involving modifying a surface with amorphous carbon provides a general and simple strategy to enhance the osteogenesis for diverse biomaterials, and this has promising potential for bone repairing applications.

Synergetic topography and chemistry cues guiding osteogenic differentiation in bone marrow stromal cells through ERK1/2 and p38 MAPK signaling pathway.

Both the topographic surface and chemical composition modification can enhance rapid osteogenic differentiation and bone formation. Till now, the synergetic effects of topography and chemistry cues guiding biological responses have been rarely reported. Herein, the ordered micro-patterned topography and classically essential trace element of strontium (Sr) ion doping were selected to imitate topography and chemistry cues, respectively. The ordered micro-patterned topography on Sr ion-doped bioceramics was successfully duplicated using the nylon sieve as the template. Biological response results revealed that the micro-patterned topography design or Sr doping could promote cell attachment, ALP activity, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Most importantly, the samples both with micro-patterned topography and Sr doping showed the highest promotion effects, and could synergistically activate the ERK1/2 and p38 MAPK signaling pathways. The results suggested that the grafts with both specific topography and chemistry cues have synergetic effects on osteogenic activity of BMSCs and provide an effective approach to design functional bone grafts and cell culture substrates.

Enhancing the Osteogenic Differentiation and Rapid Osseointegration of 3D Printed Ti6Al4V Implants via Nano-Topographic Modification.

Personalized precision therapy and rapid osseointegration are the main development directions of dental implants. Three-dimensional (3D) printing is the most promising method to fabricate personalized implants with complex design and structure. Rapid osseointegration guarantees the survival of implants especially at early implant time, and the surface modification via nano-technology is considered as the most effective method to promote osseointegration. Herein, the Ti6Al4V implants were fabricated by 3D-printing method then the nano-topographic surface was constructed on them to improve the biological responses. The results showed that the nano-topographic modification favored the adhesion and osteogenic differentiation of bone marrow derived mesenchymal stromal cells (BMSCs), accelerating the rapid osseointegration in vivo in rat condyle of femur model. It is reasonable to predict that 3D-printed implants with nano-topographic surface modification have a promising future in orthopedic applications.

Evaluation of the 3D Augmented Reality-Guided Intraoperative Positioning of Dental Implants in Edentulous Mandibular Models.

PURPOSE: This research aimed to propose a three-dimensional (3D) augmented reality navigation method with point cloud-based image-patient registration that could merge virtual images in the real environment for dental implants using a 3D image overlay and to evaluate its feasibility. MATERIALS AND METHODS: A total of 12 rapid prototyping mandibular models were fabricated using a 3D printing method and were divided into two groups: 3D augmented reality-guided group and traditional two-dimensional (2D) image-guided group. A point cloud-based preoperative image-to-patient registration method was introduced to replace the traditional point-to-point registration. After the registration, dental implant surgery was performed in the two model groups using an augmented reality-guided navigation method and a traditional two-dimensional image-guided navigation method. The planned and actual postoperative implant positions were compared for measuring positional implantation errors. The surgery time was also recorded and compared between the two groups. RESULTS: In the model experiment, the root-mean-square deviation of registration was 0.54 mm, and the implant surgery results showed < 1.5-mm mean linear deviation and < 5.5-degree angular deviation. The augmented reality-guided implantation showed smaller horizontal, vertical, and angular errors in the apical areas of the central incisor and the canine region. The surgery time using the augmented reality-guided navigation method was significantly shorter than that using the two-dimensional (2D) image-guided navigation method (P < .05). Moreover, the volunteer experiment demonstrated that the preoperative 3D models in situ accurately overlaid onto the surgical site. CONCLUSION: The proposed point cloud-based registration method can achieve excellent registration accuracy. Dental implant placement guided by the proposed 3D augmented reality navigation method showed better accuracy and applicability, as well as higher efficiency, than the traditional 2D image navigation method.

Silane modified upconversion nanoparticles with multifunctions: imaging, therapy and hypoxia detection.

Herein, we report a facile route to synthesize silane coated upconversion nanoparticles (UCNPs@silane) with an ultrathin layer (the thickness: 1-2 nm), which not only provides good biocompatibility, but also affords hydrophobic interspace to load organic molecules to realize multifunctions. Besides the function of upconversion imaging of UCNPs, cancer therapy and oxygen level detection can also be realized by the addition of chemotherapy drug, PTX, and oxygen sensitive molecules, Platinum (II) octaethylporphine (PtOEP). In bio-experiments, besides the MTT assays, therapy efficacy of UCNPs@PTX@silane can also be detected with the confocal laser scanning microscopy (CLSM) by staining methods. UCNPs@PtOEP@silane can afford minimally invasive analysis of dissolved oxygen and then respond sensitively to the variance of intracellular oxygen concentration affected by therapeutic UCNPs@PTX@silane.

[Coblation-assisting uvulopalatopharyngoplasty combining coblation-channeling of the tongue for patients with severe OSAHS].

OBJECTIVE: To investigate the therapeutic efficacy of coblation-assisting uvulopalatopharyngoplasty (CAUPPP) combining with coblation-channeling of the tongue (CCT) for patients with severe obstructive sleep apnea-hypopnea syndrome (OSAHS). METHOD: A retrospective analysis was made on patients with severe OSAHS treated by CAUPPP combining with CCT. The adult with severe OSAHS were involved in the study and the apnea-hypopnea index (AHI) were beyond 40/h and lowest arterial oxygen saturation (LSaO2) were under or equal to 80%. Surgical approach: The UPPP was performed to decrease the size of soft palate with coblation and coblation-channeling in the soft palate and decrease the size of tongue by CCT. All patients were followed up for 6 to 12 months and underwent polysomnography (PSG). RESULT: Subjective symptoms of patients improved more significantly than that of preoperation. The function of soft palate is normal without significant nasopharyngeal regurgitation. Compared with the preoperative data, AHI values were significantly decreased (P<0.01) and the lowest oxygen saturations increased significantly (P<0.01) and the effective rate was 91.7%. CONCLUSION: There are usually multiple obstruction levels in patients with severe OSAHS and the traditional surgical treatment is not ideal. This study demonstrated that with the assistance of coblation, combining CAUPPP with CCT for patients with severe OSAHS is an effective surgical method. It has less blood loss, minimally invasive, retained the normal function of the soft palate, etc., should be widely applied.

[Coblation treatment of partial tonsillectomy in children with obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To investigate the efficacy and feasibility of coblation treatment of partial tonsillectomy in children with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHOD: The clinical datum of 91 children with OSAHS were retrospective analysis during the period from January 2009 to November 2009. All subjects, the main obstructive lesions were hypertrophy of tonsils and adenoids ,and which without recurrent pharyngodynia and tonsillitis, were applied with coblation treatment of partial tonsillectomy and adenoid ablation. RESULT: Intraoperative blood loss was about 1-2 ml in all subjects,no primary and delayed hemorrhage happened and postoperative pain happened. All subjects were followed-up for 12 months to 22 months, symptoms of snoring and mouth breathing disappeared. No tonsil regeneration and repeated inflammatory episode was found. CONCLUSION: Coblation treatment of partial tonsillectomy in children with OSAHS is micro-invasive, safe and effective, which is suitable for children of different age groups with hypertrophy of tonsils.