Accurate allocation of multimapped reads enables regulatory element analysis at repeats.

Transposable elements (TEs) and other repetitive regions have been shown to contain gene regulatory elements, including transcription factor binding sites. However, regulatory elements harbored by repeats have proven difficult to characterize using short-read sequencing assays such as ChIP-seq or ATAC-seq. Most regulatory genomics analysis pipelines discard "multimapped" reads that align equally well to multiple genomic locations. Because multimapped reads arise predominantly from repeats, current analysis pipelines fail to detect a substantial portion of regulatory events that occur in repetitive regions. To address this shortcoming, we developed Allo, a new approach to allocate multimapped reads in an efficient, accurate, and user-friendly manner. Allo combines probabilistic mapping of multimapped reads with a convolutional neural network that recognizes the read distribution features of potential peaks, offering enhanced accuracy in multimapping read assignment. Allo also provides read-level output in the form of a corrected alignment file, making it compatible with existing regulatory genomics analysis pipelines and downstream peak-finders. In a demonstration application on CTCF ChIP-seq data, we show that Allo results in the discovery of thousands of new CTCF peaks. Many of these peaks contain the expected cognate motif and/or serve as TAD boundaries. We additionally apply Allo to a diverse collection of ENCODE ChIP-seq data sets, resulting in multiple previously unidentified interactions between transcription factors and repetitive element families. Finally, we show that Allo may be particularly beneficial in identifying ChIP-seq peaks at centromeres, near segmentally duplicated genes, and in younger TEs, enabling new regulatory analyses in these regions.

Recycling of coal seam gas-associated water using vacuum membrane distillation.

Coal seam gas-associated water (CSGAW), which is a by-product of coal seam gas (CSG) production typically contains significant amounts of salts and has potential environmental issues. In this study, we optimized a bench-scale vacuum membrane distillation (VMD) process with flat-sheet hydrophobic polytetrafluoroethylene (PTFE) membranes for the treatment of synthetic CSGAW (conductivity = 15 mS/cm). To study performance of the VMD process, we explored the effects of feed temperature (T(f) = 60, 70, and 80°C), feed flow rate (V(f) = 60, 120, and 240 mL/min), and vacuum pressure (P(v) = 3, 6, and 9 kPa) on water permeability through the PTFE membrane in the VMD process. Under the optimum conditions (i.e. T(f) = 80°C, V(f) = 240 mL/min, P(v) = 3 kPa), water permeability and rejection efficiency of salts by the VMD process were found to be 5.5 L/m(2)/h (LMH) and 99.9%, respectively, after 2 h filtration. However, after 8 h operation, the water permeability decreased by 70% compared with the initial flux due to the formation of fouling layer of calcium, chloride, sodium, magnesium, and potassium on the membrane surface.

Unexpected sequel to the application of silver fluoride followed by stannous fluoride to an open carious lesion in a primary molar: A case report.

OBJECTIVES: The use of silver fluoride followed by stannous fluoride was designed for the treatment of open carious lesions in primary molars in dental outreach programs. However, during the COVID-19 pandemic when aerosol-producing procedures were inadvisable, one dental location started using it as the first stage in a two-visit restorative procedure for carious primary molars. If the gap between the fluoride application and the restoration placement stages was around 3-5 weeks it was noticed that a black friable crust appeared on the caries surface. To investigate further a normally discarded crust from one patient was retrieved and sent for analysis. MATERIALS AND METHODS: Two techniques suitable for identification and preliminary analysis of material of unknown composition, scanning electron microscopy and energy dispersive spectroscopy (EDS) were used. The only preparation was that the specimen was dried and coated beforehand. RESULTS AND CONCLUSIONS: This preliminary examination showed two unexpected findings. The first was that the crust surface indicated a possible dentine derivation as it was covered with reasonably evenly spaced holes. In addition, the EDS spectrum showed it to be, at least, partially mineralized. The second unexpected finding was that the surface was coated with electron-dense particles. The size of the particles and the EDS spectrum pointed to the likelihood of the majority of them being nanosilver. These unexpected findings suggest a possible new direction for research.

A comparative study on the inhibitory effects of different parts and chemical constituents of pomegranate on α-amylase and α-glucosidase.

Pomegranate has been documented for the management of diabetes in Unani and Chinese medicine. This study compared the effects of the extracts of different pomegranate parts, including juice, peels, seeds and flowers, on carbohydrate digestive enzymes (α-amylase and α-glucosidase) in vitro. The methanolic flower extract inhibited α-amylase and α-glucosidase, while the methanolic peel extract inhibited α-glucosidase selectively. The most active flower extract was subjected to water-ethyl acetate partition. The ethyl acetate fraction was more potent than the water fraction in inhibiting both enzymes. Gallic acid and ellagic acid also showed selective inhibition against α-glucosidase, and their presence in the ethyl acetate fraction was confirmed by HPLC-DAD and HPLC-HESI-MS. Our findings suggest that the inhibition of carbohydrate digestive enzymes and their phenolic content may contribute to the anti-hyperglycaemic effects of pomegranate flower and peel, and support their claims in diabetes.

Allo: Accurate allocation of multi-mapped reads enables regulatory element analysis at repeats.

Transposable elements (TEs) and other repetitive regions have been shown to contain gene regulatory elements, including transcription factor binding sites. Unfortunately, regulatory elements harbored by repeats have proven difficult to characterize using short-read sequencing assays such as ChIP-seq or ATAC-seq. Most regulatory genomics analysis pipelines discard "multi-mapped" reads that align equally well to multiple genomic locations. Since multi-mapped reads arise predominantly from repeats, current analysis pipelines fail to detect a substantial portion of regulatory events that occur in repetitive regions. To address this shortcoming, we developed Allo, a new approach to allocate multi-mapped reads in an efficient, accurate, and user-friendly manner. Allo combines probabilistic mapping of multi-mapped reads with a convolutional neural network that recognizes the read distribution features of potential peaks, offering enhanced accuracy in multi-mapping read assignment. Allo also provides read-level output in the form of a corrected alignment file, making it compatible with existing regulatory genomics analysis pipelines and downstream peak-finders. In a demonstration application on CTCF ChIP-seq data, we show that Allo results in the discovery of thousands of new CTCF peaks. Many of these peaks contain the expected cognate motif and/or serve as TAD boundaries. We additionally apply Allo to a diverse collection of ENCODE ChIP-seq datasets, resulting in multiple previously unidentified interactions between transcription factors and repetitive element families. Finally, we show that Allo may be particularly effective in identifying ChIP-seq peaks in younger TEs, which hold evolutionary significance due to their emergence during human evolution from primates.

The Reverse Fragility Index: Interpreting the Current Literature on Long-Term Survivorship of Computer-Navigated Versus Conventional TKA: A Systematic Review and Cross-Sectional Study of Randomized Controlled Trials.

BACKGROUND: Despite the most recent American Academy of Orthopaedic Surgeons clinical practice guideline making a "strong" recommendation against the use of intraoperative navigation in total knee arthroplasty (TKA), its use is increasing. We utilized the concept of the reverse fragility index (RFI) to assess the strength of neutrality of the randomized controlled trials (RCTs) comparing the long-term survivorship of computer-navigated and conventional TKA. METHODS: A systematic review was performed including all RCTs through August 3, 2021, comparing the long-term outcomes of computer-navigated and conventional TKA. Randomized trials with mean follow-up of >8 years and survivorship with revision as the end point were included. The RFI quantifies the strength of a study's neutrality by calculating the minimum number of events necessary to flip the result from nonsignificant to significant. The RFI at a threshold of p < 0.05 was calculated for each study reporting nonsignificant results. The reverse fragility quotient (RFQ) was calculated by dividing the RFI by the study sample size. RESULTS: Ten clinical trials with 2,518 patients and 38 all-cause revisions were analyzed. All 10 studies reported nonsignificant results. The median RFI at the p < 0.05 threshold was 4, meaning that a median of 4 events would be needed to change the results from nonsignificant to significant. The median RFQ was 0.029, indicating that the nonsignificance of the results was contingent on only 2.9 events per 100 participants. The median loss to follow-up was 27 patients. In all studies, the number of patients lost to follow-up was greater than the RFI. CONCLUSIONS: The equipoise in long-term survivorship between computer-navigated and conventional TKA rests on fragile studies, as their statistical nonsignificance could be reversed by changing the outcome status of only a handful of patients--a number that was always smaller than the number lost to follow-up. Routine reporting of the RFI in trials with nonsignificant findings may provide readers with a measure of confidence in the neutrality of the results. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Novel injectable strontium-hardystonite phosphate cement for cancellous bone filling applications.

Injectable bone cement (IBC) such as those based on methacrylates and hydraulic calcium phosphate and calcium sulfate-based cements have been used extensively for filling bone defects with acceptable clinical outcomes. There is a need however for novel IBC materials that can address some of the inherent limitations of currently available formulations to widen the clinical application of IBC. In this study, we characterized a novel hydraulic IBC formulation consisting of bioactive strontium-doped hardystonite (Sr-HT) ceramic microparticles and sodium dihydrogen phosphate, herein named Sr-HT phosphate cement (SPC). The resultant cement is comprised of two distinct amorphous phases with embedded partially reacted crystalline reactants. The novel SPC formulation possesses a unique combination of physicochemical properties suitable for use as an IBC, and demonstrates in vitro cytocompatibility when seeded with primary human osteoblasts. In vivo injection of SPC into rabbit sinus defects show minor new bone formation at the SPC periphery, similar to those exhibited in sinus defects filled with a clinically available calcium phosphate cement. The current SPC formulation presented in this paper shows promise as a clinically applicable IBC which can be further enhanced with additives.

Effect of Baghdadite Substitution on the Physicochemical Properties of Brushite Cements.

Brushite cements have been clinically used for irregular bone defect filling applications, and various strategies have been previously reported to modify and improve their physicochemical properties such as strength and injectability. However, strategies to address other limitations of brushite cements such as low radiopacity or acidity without negatively impacting mechanical strength have not yet been reported. In this study, we report the effect of substituting the beta-tricalcium phosphate reactant in brushite cement with baghdadite (Ca3ZrSi2O9), a bioactive zirconium-doped calcium silicate ceramic, at various concentrations (0, 5, 10, 20, 30, 50, and 100 wt%) on the properties of the final brushite cement product. X-ray diffraction profiles indicate the dissolution of baghdadite during the cement reaction, without affecting the crystal structure of the precipitated brushite. EDX analysis shows that calcium is homogeneously distributed within the cement matrix, while zirconium and silicon form cluster-like aggregates with sizes ranging from few microns to more than 50 µm. X-ray images and µ-CT analysis indicate enhanced radiopacity with increased incorporation of baghdadite into brushite cement, with nearly a doubling of the aluminium equivalent thickness at 50 wt% baghdadite substitution. At the same time, compressive strength of brushite cement increased from 12.9 ± 3.1 MPa to 21.1 ± 4.1 MPa with 10 wt% baghdadite substitution. Culture medium conditioned with powdered brushite cement approached closer to physiological pH values when the cement is incorporated with increasing amounts of baghdadite (pH = 6.47 for pure brushite, pH = 7.02 for brushite with 20 wt% baghdadite substitution). Baghdadite substitution also influenced the ionic content in the culture medium, and subsequently affected the proliferative activity of primary human osteoblasts in vitro. This study indicates that baghdadite is a beneficial additive to enhance the radiopacity, mechanical performance and cytocompatibility of brushite cements.

Modulatory effect of simultaneously released magnesium, strontium, and silicon ions on injectable silk hydrogels for bone regeneration.

Injectable silk hydrogels are ideal carriers of therapeutic agents due to their biocompatibility and low immunogenicity. Injectable silk hydrogels for bone regeneration have been previously developed but often utilize expensive biologics. In this study, we have developed an injectable silk composite incorporated with a triphasic ceramic called MSM-10 (54 Mg2SiO4, 36 Si3Sr5 and 10 MgO (wt%)) capable of simultaneously releasing magnesium, silicon, and strontium ions into its environment. These ions have been previously reported to possess therapeutic effects for bone regeneration. MSM-10 particles were incorporated into the silk hydrogels at various weight percentages [0.1 (SMH-0.1), 0.6 (SMH-0.6), 1 (SMH-1) and 2 (SMH-2)]. The effects of the released ions on the physicochemical and biological properties of the silk hydrogel were comprehensively evaluated. Increased MSM-10 loading was found to hinder the gelation kinetics of the silk hydrogel through the reduction of beta-sheet phase formation, which in turn affected the required sonication time for gelation, compressive strength, force of injection, microstructure and in vitro degradation rate. Primary human osteoblasts seeded on SMH-0.6 demonstrated increased proliferation and early alkaline phosphatase activity, as well as enhanced osteogenic gene expression compared to pure silk hydrogel and SMH-0.1. In vivo results in subcutaneous mouse models showed both decreased fibrous capsule formation and increased number of new blood vessels around the injected SMH-0.1 and SMH-0.6 implants compared to pure silk hydrogels. The results in this study indicate that the ions released from MSM-10 is able to influence the physicochemical and biological properties of silk hydrogels, and SMH-0.6 in particular shows promising properties for bone regeneration.

High-flux ceramic membranes with a nanomesh of metal oxide nanofibers.

Traditional ceramic separation membranes, which are fabricated by applying colloidal suspensions of metal hydroxides to porous supports, tend to suffer from pinholes and cracks that seriously affect their quality. Other intrinsic problems for these membranes include dramatic losses of flux when the pore sizes are reduced to enhance selectivity and dead-end pores that make no contribution to filtration. In this work, we propose a new strategy for addressing these problems by constructing a hierarchically structured separation layer on a porous substrate using large titanate nanofibers and smaller boehmite nanofibers. The nanofibers are able to divide large voids into smaller ones without forming dead-end pores and with the minimum reduction of the total void volume. The separation layer of nanofibers has a porosity of over 70% of its volume, whereas the separation layer in conventional ceramic membranes has a porosity below 36% and inevitably includes dead-end pores that make no contribution to the flux. This radical change in membrane texture greatly enhances membrane performance. The resulting membranes were able to filter out 95.3% of 60-nm particles from a 0.01 wt % latex while maintaining a relatively high flux of between 800 and 1000 L/m2.h, under a low driving pressure (20 kPa). Such flow rates are orders of magnitude greater than those of conventional membranes with equal selectivity. Moreover, the flux was stable at approximately 800 L/m2.h with a selectivity of more than 95%, even after six repeated runs of filtration and calcination. Use of different supports, either porous glass or porous alumina, had no substantial effect on the performance of the membranes; thus, it is possible to construct the membranes from a variety of supports without compromising functionality. The Darcy equation satisfactorily describes the correlation between the filtration flux and the structural parameters of the new membranes. The assembly of nanofiber meshes to combine high flux with excellent selectivity is an exciting new direction in membrane fabrication.

NH(4)OH-KOH pulping mechanisms and kinetics of rice straw.

The mechanisms and kinetics of NH(4)OH-KOH mixture pulping rice straw were studied. When aqueous ammonia was mixed with a small amount of caustic potash (ratio of 1:5), three distinct delignification phases were observed in the pulping process: a bulk delignification phase from the beginning of the cooking period to 100 degrees C, a supplementary delignification phase from 100 degrees C to 155 degrees C lasting a further 45 min, and a residual delignification phase until the end of the cooking period. There were two silica removal phases; the first phase was from the beginning of the cooking period to 100 degrees C and the second phase was from 100 degrees C to the end of the cooking period. The rate of delignification reaction was first order with respect to residual lignin and 0.3 order with respect to [OH(-)]. The silica removal was pseudo-first-order with respect to residual silica and 0.6 order with respect to [OH(-)]. The activation energies of the delignification and removal of silica reactions were 35.6 and 30.9 kJ/mol, respectively.

A new pulping process for wheat straw to reduce problems with the discharge of black liquor.

Aqueous ammonia mixed with caustic potash as wheat straw pulping liquor was investigated. The caustic potash did not only reduce the NH3 usage and cooking time, but also provided a potassium source as a fertilizer in the black liquor. Excess NH3 in the black liquor was recovered and reused by batch distillation with a 98% recovery rate of free NH3. The black liquor was further treated for reuse by coagulation under alkaline conditions. The effects of different flocculation conditions, such as the dosage of 10% aluminium polychloride, the dosage of 0.1% polyacrylamide, the reaction temperature and the pH of the black liquor on the flocculating process were studied. The supernatant was recycled as cooking liquor by adding extra NH4OH and KOH. The amount of delignification and the pulp yield for the process remained steady at 82-85% and 48-50%, respectively, when reusing the supernatant four times. The coagulated residues could be further processed as solid fertilizers. This study provided a new pulping process for wheat straw to reduce problems of discharge black liquor.

Strontium-doped calcium silicate bioceramic with enhanced in vitro osteogenic properties.

Gehlenite (GLN, Ca2SiAl2O7) is a bioceramic that has been recently shown to possess excellent mechanical strength and in vitro osteogenic properties for bone regeneration. Substitutional incorporation of strontium in place of calcium is an effective way to further enhance biological properties of calcium-based bioceramics and glasses. However, such strategy has the potential to affect other important physicochemical parameters such as strength and degradation due to differences in the ionic radius of strontium and calcium. This study is the first to investigate the effect of a range of concentrations of strontium substitution of calcium at 1, 2, 5, 10 mol% (S1-GLN, S2-GLN, S5-GLN and S10-GLN) on the physicochemical and biological properties of GLN. We showed that up to 2 mol% strontium ion substitution retains the monophasic GLN structure when sintered at 1450 °C, whereas higher concentrations resulted in presence of calcium silicate impurities. Increased strontium incorporation resulted in changes in grain morphology and reduced densification when the ceramics were sintered at 1450 °C. Porous GLN, S1-GLN and S2-GLN scaffolds (∼80% porosity) showed compressive strengths of 2.05 ± 0.46 MPa, 1.76 ± 0.79 MPa and 1.57 ± 0.52 MPa respectively. S1-GLN and S2-GLN immersed in simulated body fluid showed increased strontium ion release but reduced calcium and silicon ion release compared to GLN without affecting overall weight loss and pH over a 21 d period. The bioactivity of the S2-GLN ceramics was significantly improved as reflected in the significant upregulation of HOB proliferation and differentiation compared to GLN. Overall, these results suggest that increased incorporation of strontium presents a trade-off between bioactivity and mechanical strength for GLN bioceramics. This is an important consideration in the development of strontium-doped bioceramics.

Transection and explantation of intraocular lenses using femtosecond lasers.

We present 2 cases in which a femtosecond laser was used in vitro to transect hydrophilic acrylic intraocular lenses (IOLs). At 8 µJ with 3 µm spot separation and 6 µm line separation, no charring occurred and there was no increase in total organic carbon. In vivo, the IOLs were successfully transected in the capsular bag (Case 1, opaque IOL) and the sulcus (Case 2, subluxated IOL post-pneumatic displacement of submacular hemorrhage) and explanted through a clear corneal incision (∼3.0 mm). At 3 months, in Case 1, the corrected distance visual acuity (CDVA) improved from 6/24 to 6/5, astigmatism improved by 0.23 diopters, and endothelial cell density (ECD) remained unchanged (1935 to 2210 cells/mm2); in Case 2, the CDVA was hand motion, astigmatism remained unchanged, and ECD decreased (1960 to 1600 cells/mm2), possibly as a result of complex surgery. Femtosecond IOL transection and explantation may be a clinically safe and feasible option for surgeons.

Tuning the Synthesis of Manganese Oxides Nanoparticles for Efficient Oxidation of Benzyl Alcohol.

The liquid phase oxidation of benzyl alcohol is an important reaction for generating benzaldehyde and benzoic acid that are largely required in the perfumery and pharmaceutical industries. The current production systems suffer from either low conversion or over oxidation. From the viewpoint of economy efficiency and environmental demand, we are aiming to develop new high-performance and cost-effective catalysts based on manganese oxides that can allow the green aerobic oxidation of benzyl alcohol under mild conditions. It was found that the composition of the precursors has significant influence on the structure formation and surface property of the manganese oxide nanoparticles. In addition, the crystallinity of the resulting manganese nanoparticles was gradually improved upon increasing the calcination temperature; however, the specific surface area decreased obviously due to pore structure damage at higher calcination temperature. The sample calcined at the optimal temperature of 600 °C from the precursors without porogen was a Mn3O4-rich material with a small amount of Mn2O3, which could generate a significant amount of [Formula: see text] species on the surface that contributed to the high catalytic activity in the oxidation. Adding porogen with precursors during the synthesis, the obtained catalysts were mainly Mn2O3 crystalline, which showed relatively low activity in the oxidation. All prepared samples showed high selectivity for benzaldehyde and benzoic acid. The obtained catalysts are comparable to the commercial OMS-2 catalyst. The synthesis-structure-catalysis interaction has been addressed, which will help for the design of new high-performance selective oxidation catalysts.

A bioceramic with enhanced osteogenic properties to regulate the function of osteoblastic and osteocalastic cells for bone tissue regeneration.

Bioceramics for regenerative medicine applications should have the ability to promote adhesion, proliferation and differentiation of osteoblast and osteoclast cells. Osteogenic properties of the material are essential for rapid bone regeneration and new bone formation. The aim of this study was to develop a silicate-based ceramic, gehlenite (GLN, Ca2Al2SiO7), and characterise its physiochemical, biocompatibility and osteogenic properties. A pure GLN powder was synthesised by a facile reactive sintering method and compacted to disc-shaped specimens. The sintering behaviour and degradation of the GLN discs in various buffer solutions were fully characterised. The cytotoxicity of GLN was evaluated by direct and indirect methods. In the indirect method, primary human osteoblast cells (HOBs) were exposed to diluted extracts (100, 50, 25, 12.5 and 6.25 mg ml(-1)) of fine GLN particles in culture medium. The results showed that the extracts did not cause any cytotoxic effect on the HOBs with the number of cells increasing significantly from day 1 to day 7. GLN-supported HOB attachment and proliferation, and significantly enhanced osteogenic gene expression levels (Runx2, osteocalcin, osteopontin and bone sialoprotein) were compared with biphasic calcium phosphate groups (BCP, a mixture of hydroxyapatite (60wt.%) and ß-tricalcium phosphate(40wt.%)). We also demonstrated that in addition to supporting HOB attachment and proliferation, GLN promoted the formation of tartrate-acid resistance phosphatase (TRAP) positive multinucleated osteoclastic cells (OCs) derived from mouse bone marrow cells. Results also demonstrated the ability of GLN to support the polarisation of OCs, a prerequisite for their functional resorptive activity which is mainly influenced by the composition and degradability of biomaterials. Overall, the developed GLN is a prospective candidate to be used in bone regeneration applications due its effective osteogenic properties and biocompatibility.

Intraocular Lens Fragmentation Using Femtosecond Laser: An In Vitro Study.

PURPOSE: To transect intraocular lenses (IOLs) using a femtosecond laser in cadaveric human eyes. To determine the optimal in vitro settings, to detect and characterize gasses or particles generated during this process. METHODS: A femtosecond laser was used to transect hydrophobic and hydrophilic acrylic lenses. The settings required to enable easy separation of the lens fragment were determined. The gasses and particles generated were analysed using gas chromatography mass spectrometer (GC-MS) and total organic carbon analyzer (TOC), respectively. RESULTS: In vitro the IOL fragments easily separated at the lowest commercially available energy setting of 1 µJ, 8-µm spot, and 2-µm line separation. No particles were detected in the 0.5- to 900-µm range. No significant gasses or other organic breakdown by products were detected at this setting. At much higher energy levels 12 µJ (4 × 6 µm spot and line separation) significant pyrolytic products were detected, which could be harmful to the eye. In cadaveric explanted IOL capsule complex the laser pulses could be applied through the capsule to the IOL and successfully fragment the IOL. CONCLUSION: IOL transection is feasible with femtosecond lasers. Further in vivo animal studies are required to confirm safety. TRANSLATIONAL RELEVANCE: In clinical practice there are a number of large intraocular lenses that can be difficult to explant. This in-vitro study examines the possibility of transecting the lasers quickly using femtosecond lasers. If in-vivo studies are successful, then this innovation could help ophthalmic surgeons in IOL explantation.

Fabrication of a novel triphasic and bioactive ceramic and evaluation of its in vitro and in vivo cytocompatibility and osteogenesis.

We report, for the first time, the synthesis of a novel triphasic and crystalline bioactive ceramic (MSM-10) with the ability to simultaneously release three types of bioactive ions (strontium (Sr), silicon (Si) and magnesium (Mg)) to the surrounding microenvironment. An MSM-10 powder with a nominal composition (wt%) of 54 Mg2SiO4, 36 Si3Sr5 and 10 MgO was prepared by the sol-gel method and fabricated as porous scaffolds using the foam replication method. The effects of the different amounts of the phases in the ceramics on the mechanical and physical properties of the scaffolds as well as their in vitro and in vivo behaviors were comprehensively investigated. Biphasic calcium phosphate (BCP, ß-tricalcium phosphate (60 wt%)/hydroxyapatite (40 wt%)) scaffolds were used as the control material. The attachment, morphology, proliferation and differentiation of primary human osteoblasts (HOBs) were investigated after cell culturing on the various scaffolds. In vitro cytotoxicity (ISO/EN 10993-5) results not only indicated the biocompatibility of MSM-10, but also its positive effects on inducing the proliferation of HOBs. Our results showed significant enhancement in osteogenic gene expression levels (Runx2, osteocalcin, osteopontin and bone sialoprotein), when HOBs were cultured on MSM-10, compared to those for BCP and other generated ceramic scaffolds. For the in vivo studies, the different types of the materials were seeded with cultured human mesenchymal stem cells (hMSC) and then subcutaneously transplanted into the dorsal surface of eight-week-old immunocompromised (NOD/SCID) mice. MSM-10 demonstrated a significant amount of new bone formation compared to the other groups tested with no macroscopic signs of inflammation or toxicity in the tissue surrounding the implants. The novel MSM-10 ceramic presents promising potential for bone regeneration in orthopaedic and maxillofacial applications.

Thermal-crosslinked porous chitosan scaffolds for soft tissue engineering applications.

The aim of this study was to demonstrate the feasibility of using a steam autoclave process for sterilization and simultaneously thermal-crosslinking of lyophilized chitosan scaffolds. This process is of great interest in biomaterial development due to its simplicity and low toxicity. The steam autoclave process had no significant effect on the average pore diameter (~70 µm) and overall porosity (>80%) of the resultant chitosan scaffolds, while the sterilized scaffolds possessed more homogenous pore size distribution. The sterilized chitosan scaffolds exhibited an enhanced compressive modulus (109.8 kPa) and comparable equilibrium swelling ratio (23.3). The resultant chitosan scaffolds could be used directly for in vitro cell culture without extra sterilization. The data of in vitro studies demonstrated that the scaffolds facilitated cell attachment and proliferation, indicating great potential for soft tissue engineering applications.