BACKGROUND This paper reports a rare presentation of multiple pulp stones(PSs)emerging in all teeth during mixed dentition.It offers valuable insights into the clinical diagnosis,treatment,and prognosis of multiple PS...BACKGROUND This paper reports a rare presentation of multiple pulp stones(PSs)emerging in all teeth during mixed dentition.It offers valuable insights into the clinical diagnosis,treatment,and prognosis of multiple PSs,shedding light on their occurrence during the mixed dentition period.CASE SUMMARY A 10-year-old girl presented with repeated pain in the mandibular right posterior teeth.Intraoral examination revealed carious lesions,abnormal tooth shapes,and anomalies in tooth number.Radiographic examinations showed multiple PSs with diverse shapes,sizes,and quantities in all teeth,alongside anomalies in tooth shape and number.Root canal therapy was initiated,but the patient initially lacked timely follow-up.Upon return for treatment completion,an extracted tooth revealed irregular calculus within the pulp cavity.CONCLUSION This case underscores the importance of considering multiple PSs in mixed dentition,necessitating comprehensive evaluation and management strategies.展开更多
BACKGROUND The role of epinephrine in the treatment of pulp capping in patients with reversible pulpitis is not clear.AIM To explore the role of epinephrine in the treatment of pulp capping in patients with reversible...BACKGROUND The role of epinephrine in the treatment of pulp capping in patients with reversible pulpitis is not clear.AIM To explore the role of epinephrine in the treatment of pulp capping in patients with reversible pulpitis.METHODS A total of 100 patients with reversible pulpitis who were treated in Anhui Jieshou People's Hospital from January 2020 to December 2021 were included in the study.They were categorized into an observation group(n=50;treatment with adrenaline)and a control group(n=50;treatment with zinc oxide eugenol paste).The 24-h postoperative pain,regression time of gingival congestion and redness,clinical efficacy,and incidence of adverse reactions were compared between the groups.Patients were further categorized into the ineffective and effective treatment groups based on clinical efficacy.Logistic multiple regression analysis explored factors affecting the efficacy of pulp capping treatment.RESULTS A significant difference in 24-h postoperative pain was observed between the groups(P<0.05),with a higher proportion of grade I pain noted in the observation group than in the control group(P<0.01).The regression time of gingival congestion and swelling was lower in the observation group(2.61±1.44 d and 2.73±1.36 d,respectively)than in the control group(3.85±1.47 d and 4.28±1.61 d,respectively)(P<0.05).The 2-wk postoperative total effective rate was lower in the control group(80.00%)than in the observation group(94.00%)(P<0.05).The incidence of adverse reactions was not significantly different between the control(14.00%)and observation(12.00%)groups(P>0.05).The proportion of adrenaline usage was lower(P<0.05)and that of anaerobic digestion by Streptococcus and Fusobacterium nucleatum was higher in the ineffective treatment group than in the effective treatment group(P<0.05).Logistic multiple regression analysis revealed adrenaline as a protective factor(P<0.05)and anaerobic digestion by Streptococcus and F.nucleatum as risk factors for pulp capping in reversible pulpitis(P<0.05).CONCLUSION Adrenaline demonstrated therapeutic efficacy in pulp capping treatment for reversible pulpitis,reducing pain and improving clinical symptoms safely.It is a protective factor for pulp capping,whereas Streptococcus and F.nucleatum are risk factors.Targeted measures can be implemented to improve clinical efficacy.展开更多
Human dental pulp stem cell transplantation has been shown to be an effective therapeutic strategy for spinal cord injury.However,whether the human dental pulp stem cell secretome can contribute to functional recovery...Human dental pulp stem cell transplantation has been shown to be an effective therapeutic strategy for spinal cord injury.However,whether the human dental pulp stem cell secretome can contribute to functional recovery after spinal cord injury remains unclear.In the present study,we established a rat model of spinal cord injury based on impact injury from a dropped weight and then intraperitoneally injected the rats with conditioned medium from human dental pulp stem cells.We found that the conditioned medium effectively promoted the recovery of sensory and motor functions in rats with spinal cord injury,decreased expression of the microglial pyroptosis markers NLRP3,GSDMD,caspase-1,and interleukin-1β,promoted axonal and myelin regeneration,and inhibited the formation of glial scars.In addition,in a lipopolysaccharide-induced BV2 microglia model,conditioned medium from human dental pulp stem cells protected cells from pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway.These results indicate that conditioned medium from human dental pulp stem cells can reduce microglial pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway,thereby promoting the recovery of neurological function after spinal cord injury.Therefore,conditioned medium from human dental pulp stem cells may become an alternative therapy for spinal cord injury.展开更多
BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data normalisation.Commonly,in an unreliable way,...BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data normalisation.Commonly,in an unreliable way,several studies use genes involved in essential cellular functions[glyceraldehyde-3-phosphate dehydro-genase(GAPDH),18S rRNA,andβ-actin]without paying attention to whether they are suitable for such experimental conditions or the reason for choosing such genes.Furthermore,such studies use only one gene when Minimum Information for Publication of Quantitative Real-Time PCR Experiments guidelines recom-mend two or more genes.It impacts the credibility of these studies and causes dis-tortions in the gene expression findings.For tissue engineering,the accuracy of gene expression drives the best experimental or therapeutical approaches.We cultivated DPSCs under two conditions:Undifferentiated and osteogenic dif-ferentiation,both for 35 d.We evaluated the gene expression of 10 candidates for RGs[ribosomal protein,large,P0(RPLP0),TATA-binding protein(TBP),GAPDH,actin beta(ACTB),tubulin(TUB),aminolevulinic acid synthase 1(ALAS1),tyro-sine 3-monooxygenase/tryptophan 5-monooxygenase activation protein,zeta(YWHAZ),eukaryotic translational elongation factor 1 alpha(EF1a),succinate dehydrogenase complex,subunit A,flavoprotein(SDHA),and beta-2-micro-globulin(B2M)]every 7 d(1,7,14,21,28,and 35 d)by RT-qPCR.The data were analysed by the four main algorithms,ΔCt method,geNorm,NormFinder,and BestKeeper and ranked by the RefFinder method.We subdivided the samples into eight subgroups.RESULTS All of the data sets from clonogenic and osteogenic samples were analysed using the RefFinder algorithm.The final ranking showed RPLP0/TBP as the two most stable RGs and TUB/B2M as the two least stable RGs.Either theΔCt method or NormFinder analysis showed TBP/RPLP0 as the two most stable genes.However,geNorm analysis showed RPLP0/EF1αin the first place.These algorithms’two least stable RGs were B2M/GAPDH.For BestKeeper,ALAS1 was ranked as the most stable RG,and SDHA as the least stable RG.The pair RPLP0/TBP was detected in most subgroups as the most stable RGs,following the RefFinfer ranking.CONCLUSION For the first time,we show that RPLP0/TBP are the most stable RGs,whereas TUB/B2M are unstable RGs for long-term osteogenic differentiation of human DPSCs in traditional monolayers.展开更多
A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses t...A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was developed.Alkaline solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping process.The response surface methodology(RSM)technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and properties.Temperature(105 to 155℃),alkali concentration(3%to 8%),sulfidity(20%to 30%)and retention time(19 to 221 min)were combined to evaluate their effects on hemicellulose yields and chemical structures.The optimal pre-extraction conditions identified in this work(5.75%NaOH concentration,25%sulfidity at 135℃for 60 min)successfully allowed recovering 4.8%of hemicelluloses(based on the wood dry mass)and limited damages to pulp yields and properties.The cellulose content in pulp can even be increased by about 10%.Hemicellulose emulsification properties were also evaluated,which were comparable to synthetic emulsifiers.This study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process,which has the potential to improve the economy and material utilization of pulp and paper mills.展开更多
This research aimed to investigate the effect of pulping conditions and refining intensities of wheat straw to be recommended for fluff pulp production.For this purpose,mono ethanol amine(MEA)was selected as a de-lign...This research aimed to investigate the effect of pulping conditions and refining intensities of wheat straw to be recommended for fluff pulp production.For this purpose,mono ethanol amine(MEA)was selected as a de-lignification agent at three levels of 50:50,25:75,and 15:85(MEA/water,W/V%),and soda-AQ 14 W/V%was used as a reference pulping.To investigate the optimal refining intensity,the obtained pulp was passed through a single disk laboratory refiner from 0 to 6 times and in two different consistencies(1.5 and 2.5 W/V%).Total yield,kappa number,ash content,and the Schopper-Riegler(SR°)freeness of the prepared pulps were investigated.Finally,hand sheets with a targeted basic weight of 70 g/m^(2) were made according to the related standards.The hand sheets were characterized using Fourier transform infrared(FTIR)spectroscopy and a field emission scanning electron microscope(FE-SEM).Sheet density,brightness,and mechanical properties such as burst,tensile,and tear indices were also investigated.The FE-SEM photographs showed that the texture of the hand sheet became denser as the refining intensity increased.External fibrillation on the surface of the fibers was also observed,especially on those refined with 2.5%consistency.The results of the chemical composition of wheat straw indicated that wheat straw containing a high percentage of holocellulose is an excellent candidate for the production of fluff pulp.The total yield and kappa number of MEA pulps increased with the decrease in MEA concentration.FTIR results indicated the presence of a peak related to amino groups in the pulp related to MEA pulp.The results also indicated that the mechanical properties of the papers,except for the tear index,were enhanced as the intensity of refining and the pulp consistency during refining increased.展开更多
BACKGROUND Atherosclerosis(AS),a chronic inflammatory disease of blood vessels,is a major contributor to cardiovascular disease.Dental pulp stem cells(DPSCs)are capable of exerting immunomodulatory and anti-inflammato...BACKGROUND Atherosclerosis(AS),a chronic inflammatory disease of blood vessels,is a major contributor to cardiovascular disease.Dental pulp stem cells(DPSCs)are capable of exerting immunomodulatory and anti-inflammatory effects by secreting cytokines and exosomes and are widely used to treat autoimmune and inflam-mation-related diseases.Hepatocyte growth factor(HGF)is a pleiotropic cytokine that plays a key role in many inflammatory and autoimmune diseases.AIM To modify DPSCs with HGF(DPSC-HGF)and evaluate the therapeutic effect of DPSC-HGF on AS using an apolipoprotein E-knockout(ApoE-/-)mouse model and an in vitro cellular model.METHODS ApoE-/-mice were fed with a high-fat diet(HFD)for 12 wk and injected with DPSC-HGF or Ad-Null modified DPSCs(DPSC-Null)through tail vein at weeks 4,7,and 11,respectively,and the therapeutic efficacy and mechanisms were analyzed by histopathology,flow cytometry,lipid and glucose measurements,real-time reverse transcription polymerase chain reaction(RT-PCR),and enzyme-linked immunosorbent assay at the different time points of the experiment.An in vitro inflammatory cell model was established by using RAW264.7 cells and human aortic endothelial cells(HAOECs),and indirect co-cultured with supernatant of DPSC-Null(DPSC-Null-CM)or DPSC-HGF-CM,and the effect and mechanisms were analyzed by flow cytometry,RT-PCR and western blot.Nuclear factor-κB(NF-κB)activators and inhibitors were also used to validate the related signaling pathways.RESULTS DPSC-Null and DPSC-HGF treatments decreased the area of atherosclerotic plaques and reduced the expression of inflammatory factors,and the percentage of macrophages in the aorta,and DPSC-HGF treatment had more pronounced effects.DPSCs treatment had no effect on serum lipoprotein levels.The FACS results showed that DPSCs treatment reduced the percentages of monocytes,neutrophils,and M1 macrophages in the peripheral blood and spleen.DPSC-Null-CM and DPSC-HGF-CM reduced adhesion molecule expression in tumor necrosis factor-αstimulated HAOECs and regulated M1 polarization and inflammatory factor expression in lipopolysaccharide-induced RAW264.7 cells by inhibiting the NF-κB signaling pathway.CONCLUSION This study suggested that DPSC-HGF could more effectively ameliorate AS in ApoE-/-mice on a HFD,and could be of greater value in stem cell-based treatments for AS.展开更多
Dental pulp stem/stromal cells(DPSCs)are fibroblast-like,neural crest-derived,and multipotent cells that can differentiate into several lineages.They are relatively easy to isolate from healthy and inflamed pulps,with...Dental pulp stem/stromal cells(DPSCs)are fibroblast-like,neural crest-derived,and multipotent cells that can differentiate into several lineages.They are relatively easy to isolate from healthy and inflamed pulps,with little ethical concerns and can be successfully cryopreserved and thawed.The therapeutic effects of DPSCs derived from animal or human sources have been extensively studied through in-vitro and in-vivo animal experiments and the findings indicated that DPSCs are effective not only for dental diseases but also for systemic diseases.Understanding that translational research is a critical step through which the fundamental scientific discoveries could be translated into applicable diagnostics and therapeutics that directly benefit humans,several clinical studies were carried out to generate evidence for the efficacy and safety of autogenous or allogeneic human DPSCs(hDPSCs)as a treatment modality for use in cell-based therapy,regenerative medicine/dentistry and tissue engineering.In clinical medicine,hDPSCs were effective for treating acute ischemic stroke and human exfoliated deciduous teeth-conditioned medium(SHED-CM)repaired vascular damage of the corpus cavernous,which is the main cause of erectile dysfunction.Whereas in clinical dentistry,autologous SHED was able to rege-nerate necrotic dental pulp after implantation into injured teeth,and micrografts enriched with autologous hDPSCs and collagen sponge were considered a treatment option for human intrabony defects.In contrast,hDPSCs did not add a significant regenerative effect when they were used for the treatment of post-extraction sockets.Large-scale clinical studies across diverse populations are still lacking to provide robust evidence on the safety and efficacy of hDPSCs as a new treatment option for various human diseases including dental-related problems.展开更多
BACKGROUND The self-assembly of solid organs from stem cells has the potential to greatly expand the applicability of regenerative medicine.Stem cells can self-organise into microsized organ units,partially modelling ...BACKGROUND The self-assembly of solid organs from stem cells has the potential to greatly expand the applicability of regenerative medicine.Stem cells can self-organise into microsized organ units,partially modelling tissue function and regeneration.Dental pulp organoids have been used to recapitulate the processes of tooth development and related diseases.However,the lack of vasculature limits the utility of dental pulp organoids.AIM To improve survival and aid in recovery after stem cell transplantation,we demonstrated the three-dimensional(3D)self-assembly of adult stem cell-human dental pulp stem cells(hDPSCs)and endothelial cells(ECs)into a novel type of spheroid-shaped dental pulp organoid in vitro under hypoxia and conditioned medium(CM).METHODS During culture,primary hDPSCs were induced to differentiate into ECs by exposing them to a hypoxic environment and CM.The hypoxic pretreated hDPSCs were then mixed with ECs at specific ratios and conditioned in a 3D environment to produce prevascularized dental pulp organoids.The biological characteristics of the organoids were analysed,and the regulatory pathways associated with angiogenesis were studied.RESULTS The combination of these two agents resulted in prevascularized human dental pulp organoids(Vorganoids)that more closely resembled dental pulp tissue in terms of morphology and function.Single-cell RNA sequencing of dental pulp tissue and RNA sequencing of Vorganoids were integrated to analyse key regulatory pathways associated with angiogenesis.The biomarkers forkhead box protein O1 and fibroblast growth factor 2 were identified to be involved in the regulation of Vorganoids.CONCLUSION In this innovative study,we effectively established an in vitro model of Vorganoids and used it to elucidate new mechanisms of angiogenesis during regeneration,facilitating the development of clinical treatment strategies.展开更多
Infant malnutrition is a significant issue in Côte d’Ivoire, and this study aims to address it by formulating infant flours using local ingredients. Fermentation, germination, and malting methods were used to en...Infant malnutrition is a significant issue in Côte d’Ivoire, and this study aims to address it by formulating infant flours using local ingredients. Fermentation, germination, and malting methods were used to enhance the quality of six formulated flours, all based on Fonio and supplemented with Bambara groundnut, African locust bean fruit pulp, and cashew kernels. Results showed that Fonio had the highest carbohydrate content, while Bambara groundnut and Cashew kernels were rich in protein and lipid content. African locust bean fruit pulp was rich in fiber and Vitamin C, with a high β-carotene value. The cashew kernel had the highest energy value. Regarding mineral composition, African locust bean fruit pulp had the highest potassium content, while Bambara groundnut and African locust bean fruit pulp were rich in sodium. Cashew kernel and Fonio had higher iron and calcium content. Bambara groundnut had a higher zinc content, while cashew kernel had a higher magnesium content. The formulated flours made from fermented Fonio grains and enriched with Bambara groundnut, African locust bean fruit pulp, and cashew kernel had varying protein, fiber, carbohydrate, ash, and fat contents. The flour formulated with sprouted Fonio and enriched with the same ingredients had higher protein content and energy value than the other fermented seed-based flours. The mixed flours produced with fermented seeds and the flour produced from sprouted seeds met international standards. Overall, these findings offer valuable insights into the nutritional composition of the formulated flours and their potential to combat infant malnutrition in Côte d’Ivoire.展开更多
Obesity is a chronic condition characterised by excess body fat that leads to increased body weight. One of the most effective ways to treat obesity is to use appetite suppressants to reduce food intake. This study ai...Obesity is a chronic condition characterised by excess body fat that leads to increased body weight. One of the most effective ways to treat obesity is to use appetite suppressants to reduce food intake. This study aimed to evaluate in vivo reduction of food intake and weight gain caused by Parkia biglobosa (Pb) fruit pulp. Twenty-four healthy NMRI mice divided into four groups were used for the experiment. Group 1, considered the negative control, received distilled water. Groups 2, 3, and 4 were administered daily with 100, 250 and 500 mg/kg body weight of Pb fruit pulp powder suspension, respectively. The reduction in food intake was assessed in two phases: acute food intake for one day (24 h) and long-term food intake for seven weeks. Nutrient parameters and phenolic compounds in Pb fruit pulp were quantified. The results showed that Pb fruit pulp had a significant effect on reducing acute food intake. At a dose of 250 mg/kg, Pb had the best activity in reducing acute food intake, with an overall reduction rate of approximately 47.98% ± 1.17% compared to the control. Repeated daily administration inhibited food intake with all three doses for 13 days compared to control. Food intake was significantly decreased for up to 31 days by taking a 100 mg/kg dose of Pb (p = 0.0174). Weight gain was significantly lower (p = 0.0003) in mice treated with 100 mg/kg Pb than in controls at the end of 7 weeks. According to the nutritional composition study, Pb fruit pulp contains an abundance of total carbohydrates (68.81% ± 0.32%) and crude fiber (14.35% ± 0.21%). This study demonstrated that Pb fruit pulp effectively reduces food intake in healthy mice. Pb pulp’s richness in crude fiber and phenolic compounds makes it a potential aid in managing obesity.展开更多
Cationized pulp fibers (CPF) were prepared by the adsorption of a novel biodegradable cationic ester quaternary ammonium salt (31441) on bleached softwood kraft pulp fibers. The optimized conditions for the CPF pr...Cationized pulp fibers (CPF) were prepared by the adsorption of a novel biodegradable cationic ester quaternary ammonium salt (31441) on bleached softwood kraft pulp fibers. The optimized conditions for the CPF preparation were: 4% of 31441 (based on oven-dry pulp), 80℃ and 30 rain. The CPF was characterized by FT-IR, SEM and XPS. Experimental results showed that the CPF improved the retention of precipitated calcium carbonate (PCC) filler significantly. With 0.9% CPF (based on oven-dry pulp), the retention of PCC increased from 57.53% to 72.21%. The physical properties of paper were also slightly improved. The tensile strength and burst strength of the paper with CPF were higher than those with CPAM. CPF addition had no effect on the stock drainage.展开更多
The refining performances of mixed poplar and eucalyptwoodchips(mixture ratio 6:4)were investigated at medium and highpulp consistency via chemi-mechanical pulping(CMP).The specificrefining energy consumption(SEC),fib...The refining performances of mixed poplar and eucalyptwoodchips(mixture ratio 6:4)were investigated at medium and highpulp consistency via chemi-mechanical pulping(CMP).The specificrefining energy consumption(SEC),fiber fraction proportion,andCanadian standard freeness(CSF)were determined to evaluate the effectsof pulp consistency and NaOH dosage on the refining performancesof mixed poplar and eucalypt woodchips.While the dosage of NaOHfor impregnation was maintained constant,the SEC and shive contentincreased with increasing pulp consistency.Different fractions obtainedfrom the Bauer-McNett classifier showed that higher pulp consistencycould be expected to yield more long fibers and shive in the stock.Upon increasing the NaOH dosage,the shive content and SEC reducedsignificantly.When the NaOH dosage was increased to 6%,the resultsindicated that it was difficult to reduce the shive content to less than 1%athigh pulp consistencies(25%~35%),whereas 0.18%shive fraction couldbe achieved at a medium pulp consistency(15%).展开更多
Bamboo was used as raw material for unbleached pulp production.An acetic acid prehydrolysis process was employed before the pulping process.The effect of acetic acid prehydrolysis on pulp properties was investigated.T...Bamboo was used as raw material for unbleached pulp production.An acetic acid prehydrolysis process was employed before the pulping process.The effect of acetic acid prehydrolysis on pulp properties was investigated.The results showed that some components,such as hemicellulose and extractives,were degraded or dissolved in the prehydrolysis process prior to kraft pulping.SEM images of the substrate after treatment indicated that the parenchyma cell wall was thinner,and the size of pores between fiber bundle cell walls was larger.The pulping results showed that acetic acid prehydrolysis could improve the pulp quality and make the pulp easier to bleach.The brightness of the pulp reached 59.6%ISO with a single oxygen delignification step.The acetic acid prehydrolysis decreased pulp viscosity and fiber length,but not significantly.The amount of parenchyma cells in the pulp was reduced,which was beneficial for papermaking and improving mechanical strength of paper.This procedure has good potential for unbleached pulp production.展开更多
Morphological characteristics and proximate chemical analysis of E. binata showed it as a suitable raw material for writing and printing grade paper. Maximum pulp yield (43.58%) of kappa number 17.38 with 0.9% screeni...Morphological characteristics and proximate chemical analysis of E. binata showed it as a suitable raw material for writing and printing grade paper. Maximum pulp yield (43.58%) of kappa number 17.38 with 0.9% screening rejects was obtained at 12% of active alkali (as Na2O) pulping temperature 130°C, cooking time 120 min and solid to liquor ratio 1:4. During bio-soda pulping of E. binata, pulp yield decreased slightly while pulp brightness, tensile index, burst index and double fold numbers were improved by 4.1%, 24.94%, 14.03% and 48.45% respectively compared to soda pulping. During ethanol-soda pulping of E. binata, pulp yield, pulp brightness, tensile index, burst index and double fold numbers were improved by 3.9%, 6.6%, 32.18%, 35.40% and 77.31% respectively compared to soda pulping.展开更多
Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually prese...Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.展开更多
A method of treating pulpless coloured anterior tooth is presented.Most part ofthe coloured dentin of the labial crown was removed and the dental structure was bleachedwith 30% hydrogen peroxide for 5min.The pulp cavi...A method of treating pulpless coloured anterior tooth is presented.Most part ofthe coloured dentin of the labial crown was removed and the dental structure was bleachedwith 30% hydrogen peroxide for 5min.The pulp cavity was then filled with whitephoto-curing composite.The result of the treatment is quite satisfactory.With our treatment,the intact contour of the crown and the hardness and gloss of the enamel are preserved.SEM proved that the composite was tightly bound with the enamel of the medial wall of thepulp cavity,forming an entity with the tooth,thus guaranteeing the strength of the crown.展开更多
Semaphorin 3A could be involved in angiogenesis and also enhanced bone formation was investigated in many researches. In our current study, we firstly investigated that canal obliteration might be present in some rege...Semaphorin 3A could be involved in angiogenesis and also enhanced bone formation was investigated in many researches. In our current study, we firstly investigated that canal obliteration might be present in some regenerative endodontic procedures cases clinically. After the establishment of the model of apical periodontitis in the maxillary first molars of rats, pulp revascularization was performed in mesial root canal. Histological sections showed that most of the tissues growing into the root canal were not real pulp tissue, but cementoid, osteoid and periodontal-like membrane. Moreover, we detected that the expression of Semaphorin 3A increased in the mesial root canal. When we used CoCl<sub>2</sub> to induce hypoxic environment, the expression of genes and proteins, Hypoxia inducible factor-1α, Vascular endothelial growth factor, and Semaphorin 3A in dental pulp stem cells were both upregulated. In conclusion, hypoxia mediated the high expression of Semaphorin 3A in DPSC might be involved tissue regeneration during pulp vascularization.展开更多
Introduction: The endodontic management of necrotic permanent immature teeth is a challenge for the practitioner. These teeth are treated by apexification. However, because of the complications associated with this tr...Introduction: The endodontic management of necrotic permanent immature teeth is a challenge for the practitioner. These teeth are treated by apexification. However, because of the complications associated with this treatment, researchers have developed other therapies. Currently, a new technique called pulp revascularization has emerged. This technique allows the continuation of root completion thanks to a healthy tissue newly formed at the intra root canal level. Material and method: A literature search of articles dealing with pulp revascularization of immature permanent teeth was conducted using two types of search strategy, a literature search using keywords on databases and then a manual “bottom-up” search of references of previously identified articles. Results: 112 articles were identified based on inclusion and exclusion criteria. Discussion: This work showed that pulp revascularization is a new therapy that aims to restart root development on an immature permanent tooth. It is based on the principle of tissue engineering and uses the differentiation potential of stem cells. Conclusion: Currently, the literature values revascularization as it allows root development, sidewall thickening, apical closure and a decrease in periapical lesion and ensures a good sealing. Clinical and radiographic success rates appear to be encouraging, except that factors influencing treatment must be taken into consideration.展开更多
Dental pulp stem cells (DPSCs) have emerged as a promising tool with greatpotential for use in tissue regeneration and engineering. Some of the mainadvantages of these cells are their multifaceted differentiation capa...Dental pulp stem cells (DPSCs) have emerged as a promising tool with greatpotential for use in tissue regeneration and engineering. Some of the mainadvantages of these cells are their multifaceted differentiation capacity, along withtheir high proliferation rate, a relative simplicity of extraction and culture thatenables obtaining patient-specific cell lines for their use in autologous celltherapy. PubMed, Scopus and Google Scholar databases were searched forrelevant articles related to the use of DPSCs in regeneration of dentin-pulpcomplex (DPC), periodontal tissues, salivary gland and craniomaxillofacial bonedefects. Few studies were found regarding the use of DPSCs for regeneration ofDPC. Scaffold-based combined with DPSCs isolated from healthy pulps was thestrategy used for DPC regeneration. Studies involved subcutaneous implantationof scaffolds loaded with DPSCs pretreated with odontogenic media, or performedon human tooth root model as a root slice. Most of the studies were related toperiodontal tissue regeneration which mainly utilized DPSCs/secretome. Forperiodontal tissues, DPSCs or their secretome were isolated from healthy orinflamed pulps and they were used either for preclinical or clinical studies.Regarding salivary gland regeneration, the submandibular gland was the onlymodel used for the preclinical studies and DPSCs or their secretome were isolatedonly from healthy pulps and they were used in preclinical studies. Likewise,DPSCs have been studied for craniomaxillofacial bone defects in the form ofmandibular, calvarial and craniofacial bone defects where DPSCs were isolatedonly from healthy pulps for preclinical and clinical studies. From the previousresults, we can conclude that DPSCs is promising candidate for dental and oraltissue regeneration.展开更多
基金Supported by Capital’s Funds for Health Improvement and Research,No.CFH2020-2-5021Exploration Project to Improve the Quality of Standardized Training for Resident Doctors in 2022+1 种基金Health Care Project in 2022,No.22JSZ13Haidian Frontier Project of Beijing Natural Science Foundation,No.L222110.
文摘BACKGROUND This paper reports a rare presentation of multiple pulp stones(PSs)emerging in all teeth during mixed dentition.It offers valuable insights into the clinical diagnosis,treatment,and prognosis of multiple PSs,shedding light on their occurrence during the mixed dentition period.CASE SUMMARY A 10-year-old girl presented with repeated pain in the mandibular right posterior teeth.Intraoral examination revealed carious lesions,abnormal tooth shapes,and anomalies in tooth number.Radiographic examinations showed multiple PSs with diverse shapes,sizes,and quantities in all teeth,alongside anomalies in tooth shape and number.Root canal therapy was initiated,but the patient initially lacked timely follow-up.Upon return for treatment completion,an extracted tooth revealed irregular calculus within the pulp cavity.CONCLUSION This case underscores the importance of considering multiple PSs in mixed dentition,necessitating comprehensive evaluation and management strategies.
基金The study was reviewed and approved by Anhui Jieshou People's Hospital Institutional Review Board,No.2019-11-001.
文摘BACKGROUND The role of epinephrine in the treatment of pulp capping in patients with reversible pulpitis is not clear.AIM To explore the role of epinephrine in the treatment of pulp capping in patients with reversible pulpitis.METHODS A total of 100 patients with reversible pulpitis who were treated in Anhui Jieshou People's Hospital from January 2020 to December 2021 were included in the study.They were categorized into an observation group(n=50;treatment with adrenaline)and a control group(n=50;treatment with zinc oxide eugenol paste).The 24-h postoperative pain,regression time of gingival congestion and redness,clinical efficacy,and incidence of adverse reactions were compared between the groups.Patients were further categorized into the ineffective and effective treatment groups based on clinical efficacy.Logistic multiple regression analysis explored factors affecting the efficacy of pulp capping treatment.RESULTS A significant difference in 24-h postoperative pain was observed between the groups(P<0.05),with a higher proportion of grade I pain noted in the observation group than in the control group(P<0.01).The regression time of gingival congestion and swelling was lower in the observation group(2.61±1.44 d and 2.73±1.36 d,respectively)than in the control group(3.85±1.47 d and 4.28±1.61 d,respectively)(P<0.05).The 2-wk postoperative total effective rate was lower in the control group(80.00%)than in the observation group(94.00%)(P<0.05).The incidence of adverse reactions was not significantly different between the control(14.00%)and observation(12.00%)groups(P>0.05).The proportion of adrenaline usage was lower(P<0.05)and that of anaerobic digestion by Streptococcus and Fusobacterium nucleatum was higher in the ineffective treatment group than in the effective treatment group(P<0.05).Logistic multiple regression analysis revealed adrenaline as a protective factor(P<0.05)and anaerobic digestion by Streptococcus and F.nucleatum as risk factors for pulp capping in reversible pulpitis(P<0.05).CONCLUSION Adrenaline demonstrated therapeutic efficacy in pulp capping treatment for reversible pulpitis,reducing pain and improving clinical symptoms safely.It is a protective factor for pulp capping,whereas Streptococcus and F.nucleatum are risk factors.Targeted measures can be implemented to improve clinical efficacy.
基金supported by the Research Foundation of Technology Committee of Tongzhou District,No.KJ2019CX001(to SX).
文摘Human dental pulp stem cell transplantation has been shown to be an effective therapeutic strategy for spinal cord injury.However,whether the human dental pulp stem cell secretome can contribute to functional recovery after spinal cord injury remains unclear.In the present study,we established a rat model of spinal cord injury based on impact injury from a dropped weight and then intraperitoneally injected the rats with conditioned medium from human dental pulp stem cells.We found that the conditioned medium effectively promoted the recovery of sensory and motor functions in rats with spinal cord injury,decreased expression of the microglial pyroptosis markers NLRP3,GSDMD,caspase-1,and interleukin-1β,promoted axonal and myelin regeneration,and inhibited the formation of glial scars.In addition,in a lipopolysaccharide-induced BV2 microglia model,conditioned medium from human dental pulp stem cells protected cells from pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway.These results indicate that conditioned medium from human dental pulp stem cells can reduce microglial pyroptosis by inhibiting the NLRP3/caspase-1/interleukin-1βpathway,thereby promoting the recovery of neurological function after spinal cord injury.Therefore,conditioned medium from human dental pulp stem cells may become an alternative therapy for spinal cord injury.
基金Supported by São Paulo Research Foundation(FAPESP),No.2010/08918-9 and 2020/11564-6the KBSP Young Investigator Fellowship,No.2011/00204-0+2 种基金the DBF Fellowship,No.2019/27492-7the LMG Fellowship,No.2014/01395-1the CFB Fellowship,No.2014/14278-3.
文摘BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data normalisation.Commonly,in an unreliable way,several studies use genes involved in essential cellular functions[glyceraldehyde-3-phosphate dehydro-genase(GAPDH),18S rRNA,andβ-actin]without paying attention to whether they are suitable for such experimental conditions or the reason for choosing such genes.Furthermore,such studies use only one gene when Minimum Information for Publication of Quantitative Real-Time PCR Experiments guidelines recom-mend two or more genes.It impacts the credibility of these studies and causes dis-tortions in the gene expression findings.For tissue engineering,the accuracy of gene expression drives the best experimental or therapeutical approaches.We cultivated DPSCs under two conditions:Undifferentiated and osteogenic dif-ferentiation,both for 35 d.We evaluated the gene expression of 10 candidates for RGs[ribosomal protein,large,P0(RPLP0),TATA-binding protein(TBP),GAPDH,actin beta(ACTB),tubulin(TUB),aminolevulinic acid synthase 1(ALAS1),tyro-sine 3-monooxygenase/tryptophan 5-monooxygenase activation protein,zeta(YWHAZ),eukaryotic translational elongation factor 1 alpha(EF1a),succinate dehydrogenase complex,subunit A,flavoprotein(SDHA),and beta-2-micro-globulin(B2M)]every 7 d(1,7,14,21,28,and 35 d)by RT-qPCR.The data were analysed by the four main algorithms,ΔCt method,geNorm,NormFinder,and BestKeeper and ranked by the RefFinder method.We subdivided the samples into eight subgroups.RESULTS All of the data sets from clonogenic and osteogenic samples were analysed using the RefFinder algorithm.The final ranking showed RPLP0/TBP as the two most stable RGs and TUB/B2M as the two least stable RGs.Either theΔCt method or NormFinder analysis showed TBP/RPLP0 as the two most stable genes.However,geNorm analysis showed RPLP0/EF1αin the first place.These algorithms’two least stable RGs were B2M/GAPDH.For BestKeeper,ALAS1 was ranked as the most stable RG,and SDHA as the least stable RG.The pair RPLP0/TBP was detected in most subgroups as the most stable RGs,following the RefFinfer ranking.CONCLUSION For the first time,we show that RPLP0/TBP are the most stable RGs,whereas TUB/B2M are unstable RGs for long-term osteogenic differentiation of human DPSCs in traditional monolayers.
基金supported by the Natural Science Foundation of Guangdong Province(2023A1515030211)the National Natural Science Foundation of China(22278157)Guangzhou Science and Technology Program(2023B03J1365).
文摘A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was developed.Alkaline solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping process.The response surface methodology(RSM)technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and properties.Temperature(105 to 155℃),alkali concentration(3%to 8%),sulfidity(20%to 30%)and retention time(19 to 221 min)were combined to evaluate their effects on hemicellulose yields and chemical structures.The optimal pre-extraction conditions identified in this work(5.75%NaOH concentration,25%sulfidity at 135℃for 60 min)successfully allowed recovering 4.8%of hemicelluloses(based on the wood dry mass)and limited damages to pulp yields and properties.The cellulose content in pulp can even be increased by about 10%.Hemicellulose emulsification properties were also evaluated,which were comparable to synthetic emulsifiers.This study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process,which has the potential to improve the economy and material utilization of pulp and paper mills.
基金This study was financially supported by Iranian National Science Foundation(project number of 4020345).
文摘This research aimed to investigate the effect of pulping conditions and refining intensities of wheat straw to be recommended for fluff pulp production.For this purpose,mono ethanol amine(MEA)was selected as a de-lignification agent at three levels of 50:50,25:75,and 15:85(MEA/water,W/V%),and soda-AQ 14 W/V%was used as a reference pulping.To investigate the optimal refining intensity,the obtained pulp was passed through a single disk laboratory refiner from 0 to 6 times and in two different consistencies(1.5 and 2.5 W/V%).Total yield,kappa number,ash content,and the Schopper-Riegler(SR°)freeness of the prepared pulps were investigated.Finally,hand sheets with a targeted basic weight of 70 g/m^(2) were made according to the related standards.The hand sheets were characterized using Fourier transform infrared(FTIR)spectroscopy and a field emission scanning electron microscope(FE-SEM).Sheet density,brightness,and mechanical properties such as burst,tensile,and tear indices were also investigated.The FE-SEM photographs showed that the texture of the hand sheet became denser as the refining intensity increased.External fibrillation on the surface of the fibers was also observed,especially on those refined with 2.5%consistency.The results of the chemical composition of wheat straw indicated that wheat straw containing a high percentage of holocellulose is an excellent candidate for the production of fluff pulp.The total yield and kappa number of MEA pulps increased with the decrease in MEA concentration.FTIR results indicated the presence of a peak related to amino groups in the pulp related to MEA pulp.The results also indicated that the mechanical properties of the papers,except for the tear index,were enhanced as the intensity of refining and the pulp consistency during refining increased.
文摘BACKGROUND Atherosclerosis(AS),a chronic inflammatory disease of blood vessels,is a major contributor to cardiovascular disease.Dental pulp stem cells(DPSCs)are capable of exerting immunomodulatory and anti-inflammatory effects by secreting cytokines and exosomes and are widely used to treat autoimmune and inflam-mation-related diseases.Hepatocyte growth factor(HGF)is a pleiotropic cytokine that plays a key role in many inflammatory and autoimmune diseases.AIM To modify DPSCs with HGF(DPSC-HGF)and evaluate the therapeutic effect of DPSC-HGF on AS using an apolipoprotein E-knockout(ApoE-/-)mouse model and an in vitro cellular model.METHODS ApoE-/-mice were fed with a high-fat diet(HFD)for 12 wk and injected with DPSC-HGF or Ad-Null modified DPSCs(DPSC-Null)through tail vein at weeks 4,7,and 11,respectively,and the therapeutic efficacy and mechanisms were analyzed by histopathology,flow cytometry,lipid and glucose measurements,real-time reverse transcription polymerase chain reaction(RT-PCR),and enzyme-linked immunosorbent assay at the different time points of the experiment.An in vitro inflammatory cell model was established by using RAW264.7 cells and human aortic endothelial cells(HAOECs),and indirect co-cultured with supernatant of DPSC-Null(DPSC-Null-CM)or DPSC-HGF-CM,and the effect and mechanisms were analyzed by flow cytometry,RT-PCR and western blot.Nuclear factor-κB(NF-κB)activators and inhibitors were also used to validate the related signaling pathways.RESULTS DPSC-Null and DPSC-HGF treatments decreased the area of atherosclerotic plaques and reduced the expression of inflammatory factors,and the percentage of macrophages in the aorta,and DPSC-HGF treatment had more pronounced effects.DPSCs treatment had no effect on serum lipoprotein levels.The FACS results showed that DPSCs treatment reduced the percentages of monocytes,neutrophils,and M1 macrophages in the peripheral blood and spleen.DPSC-Null-CM and DPSC-HGF-CM reduced adhesion molecule expression in tumor necrosis factor-αstimulated HAOECs and regulated M1 polarization and inflammatory factor expression in lipopolysaccharide-induced RAW264.7 cells by inhibiting the NF-κB signaling pathway.CONCLUSION This study suggested that DPSC-HGF could more effectively ameliorate AS in ApoE-/-mice on a HFD,and could be of greater value in stem cell-based treatments for AS.
文摘Dental pulp stem/stromal cells(DPSCs)are fibroblast-like,neural crest-derived,and multipotent cells that can differentiate into several lineages.They are relatively easy to isolate from healthy and inflamed pulps,with little ethical concerns and can be successfully cryopreserved and thawed.The therapeutic effects of DPSCs derived from animal or human sources have been extensively studied through in-vitro and in-vivo animal experiments and the findings indicated that DPSCs are effective not only for dental diseases but also for systemic diseases.Understanding that translational research is a critical step through which the fundamental scientific discoveries could be translated into applicable diagnostics and therapeutics that directly benefit humans,several clinical studies were carried out to generate evidence for the efficacy and safety of autogenous or allogeneic human DPSCs(hDPSCs)as a treatment modality for use in cell-based therapy,regenerative medicine/dentistry and tissue engineering.In clinical medicine,hDPSCs were effective for treating acute ischemic stroke and human exfoliated deciduous teeth-conditioned medium(SHED-CM)repaired vascular damage of the corpus cavernous,which is the main cause of erectile dysfunction.Whereas in clinical dentistry,autologous SHED was able to rege-nerate necrotic dental pulp after implantation into injured teeth,and micrografts enriched with autologous hDPSCs and collagen sponge were considered a treatment option for human intrabony defects.In contrast,hDPSCs did not add a significant regenerative effect when they were used for the treatment of post-extraction sockets.Large-scale clinical studies across diverse populations are still lacking to provide robust evidence on the safety and efficacy of hDPSCs as a new treatment option for various human diseases including dental-related problems.
基金Supported by the Science and Technology Programme of Guangzhou City,No.202201020341.
文摘BACKGROUND The self-assembly of solid organs from stem cells has the potential to greatly expand the applicability of regenerative medicine.Stem cells can self-organise into microsized organ units,partially modelling tissue function and regeneration.Dental pulp organoids have been used to recapitulate the processes of tooth development and related diseases.However,the lack of vasculature limits the utility of dental pulp organoids.AIM To improve survival and aid in recovery after stem cell transplantation,we demonstrated the three-dimensional(3D)self-assembly of adult stem cell-human dental pulp stem cells(hDPSCs)and endothelial cells(ECs)into a novel type of spheroid-shaped dental pulp organoid in vitro under hypoxia and conditioned medium(CM).METHODS During culture,primary hDPSCs were induced to differentiate into ECs by exposing them to a hypoxic environment and CM.The hypoxic pretreated hDPSCs were then mixed with ECs at specific ratios and conditioned in a 3D environment to produce prevascularized dental pulp organoids.The biological characteristics of the organoids were analysed,and the regulatory pathways associated with angiogenesis were studied.RESULTS The combination of these two agents resulted in prevascularized human dental pulp organoids(Vorganoids)that more closely resembled dental pulp tissue in terms of morphology and function.Single-cell RNA sequencing of dental pulp tissue and RNA sequencing of Vorganoids were integrated to analyse key regulatory pathways associated with angiogenesis.The biomarkers forkhead box protein O1 and fibroblast growth factor 2 were identified to be involved in the regulation of Vorganoids.CONCLUSION In this innovative study,we effectively established an in vitro model of Vorganoids and used it to elucidate new mechanisms of angiogenesis during regeneration,facilitating the development of clinical treatment strategies.
文摘Infant malnutrition is a significant issue in Côte d’Ivoire, and this study aims to address it by formulating infant flours using local ingredients. Fermentation, germination, and malting methods were used to enhance the quality of six formulated flours, all based on Fonio and supplemented with Bambara groundnut, African locust bean fruit pulp, and cashew kernels. Results showed that Fonio had the highest carbohydrate content, while Bambara groundnut and Cashew kernels were rich in protein and lipid content. African locust bean fruit pulp was rich in fiber and Vitamin C, with a high β-carotene value. The cashew kernel had the highest energy value. Regarding mineral composition, African locust bean fruit pulp had the highest potassium content, while Bambara groundnut and African locust bean fruit pulp were rich in sodium. Cashew kernel and Fonio had higher iron and calcium content. Bambara groundnut had a higher zinc content, while cashew kernel had a higher magnesium content. The formulated flours made from fermented Fonio grains and enriched with Bambara groundnut, African locust bean fruit pulp, and cashew kernel had varying protein, fiber, carbohydrate, ash, and fat contents. The flour formulated with sprouted Fonio and enriched with the same ingredients had higher protein content and energy value than the other fermented seed-based flours. The mixed flours produced with fermented seeds and the flour produced from sprouted seeds met international standards. Overall, these findings offer valuable insights into the nutritional composition of the formulated flours and their potential to combat infant malnutrition in Côte d’Ivoire.
文摘Obesity is a chronic condition characterised by excess body fat that leads to increased body weight. One of the most effective ways to treat obesity is to use appetite suppressants to reduce food intake. This study aimed to evaluate in vivo reduction of food intake and weight gain caused by Parkia biglobosa (Pb) fruit pulp. Twenty-four healthy NMRI mice divided into four groups were used for the experiment. Group 1, considered the negative control, received distilled water. Groups 2, 3, and 4 were administered daily with 100, 250 and 500 mg/kg body weight of Pb fruit pulp powder suspension, respectively. The reduction in food intake was assessed in two phases: acute food intake for one day (24 h) and long-term food intake for seven weeks. Nutrient parameters and phenolic compounds in Pb fruit pulp were quantified. The results showed that Pb fruit pulp had a significant effect on reducing acute food intake. At a dose of 250 mg/kg, Pb had the best activity in reducing acute food intake, with an overall reduction rate of approximately 47.98% ± 1.17% compared to the control. Repeated daily administration inhibited food intake with all three doses for 13 days compared to control. Food intake was significantly decreased for up to 31 days by taking a 100 mg/kg dose of Pb (p = 0.0174). Weight gain was significantly lower (p = 0.0003) in mice treated with 100 mg/kg Pb than in controls at the end of 7 weeks. According to the nutritional composition study, Pb fruit pulp contains an abundance of total carbohydrates (68.81% ± 0.32%) and crude fiber (14.35% ± 0.21%). This study demonstrated that Pb fruit pulp effectively reduces food intake in healthy mice. Pb pulp’s richness in crude fiber and phenolic compounds makes it a potential aid in managing obesity.
基金the Key Scientific and Technological Project of Heilongjiang Province (GB06B501-1)
文摘Cationized pulp fibers (CPF) were prepared by the adsorption of a novel biodegradable cationic ester quaternary ammonium salt (31441) on bleached softwood kraft pulp fibers. The optimized conditions for the CPF preparation were: 4% of 31441 (based on oven-dry pulp), 80℃ and 30 rain. The CPF was characterized by FT-IR, SEM and XPS. Experimental results showed that the CPF improved the retention of precipitated calcium carbonate (PCC) filler significantly. With 0.9% CPF (based on oven-dry pulp), the retention of PCC increased from 57.53% to 72.21%. The physical properties of paper were also slightly improved. The tensile strength and burst strength of the paper with CPF were higher than those with CPAM. CPF addition had no effect on the stock drainage.
文摘The refining performances of mixed poplar and eucalyptwoodchips(mixture ratio 6:4)were investigated at medium and highpulp consistency via chemi-mechanical pulping(CMP).The specificrefining energy consumption(SEC),fiber fraction proportion,andCanadian standard freeness(CSF)were determined to evaluate the effectsof pulp consistency and NaOH dosage on the refining performancesof mixed poplar and eucalypt woodchips.While the dosage of NaOHfor impregnation was maintained constant,the SEC and shive contentincreased with increasing pulp consistency.Different fractions obtainedfrom the Bauer-McNett classifier showed that higher pulp consistencycould be expected to yield more long fibers and shive in the stock.Upon increasing the NaOH dosage,the shive content and SEC reducedsignificantly.When the NaOH dosage was increased to 6%,the resultsindicated that it was difficult to reduce the shive content to less than 1%athigh pulp consistencies(25%~35%),whereas 0.18%shive fraction couldbe achieved at a medium pulp consistency(15%).
基金financial support from the National Natural Science Foundation of China (31570569)
文摘Bamboo was used as raw material for unbleached pulp production.An acetic acid prehydrolysis process was employed before the pulping process.The effect of acetic acid prehydrolysis on pulp properties was investigated.The results showed that some components,such as hemicellulose and extractives,were degraded or dissolved in the prehydrolysis process prior to kraft pulping.SEM images of the substrate after treatment indicated that the parenchyma cell wall was thinner,and the size of pores between fiber bundle cell walls was larger.The pulping results showed that acetic acid prehydrolysis could improve the pulp quality and make the pulp easier to bleach.The brightness of the pulp reached 59.6%ISO with a single oxygen delignification step.The acetic acid prehydrolysis decreased pulp viscosity and fiber length,but not significantly.The amount of parenchyma cells in the pulp was reduced,which was beneficial for papermaking and improving mechanical strength of paper.This procedure has good potential for unbleached pulp production.
文摘Morphological characteristics and proximate chemical analysis of E. binata showed it as a suitable raw material for writing and printing grade paper. Maximum pulp yield (43.58%) of kappa number 17.38 with 0.9% screening rejects was obtained at 12% of active alkali (as Na2O) pulping temperature 130°C, cooking time 120 min and solid to liquor ratio 1:4. During bio-soda pulping of E. binata, pulp yield decreased slightly while pulp brightness, tensile index, burst index and double fold numbers were improved by 4.1%, 24.94%, 14.03% and 48.45% respectively compared to soda pulping. During ethanol-soda pulping of E. binata, pulp yield, pulp brightness, tensile index, burst index and double fold numbers were improved by 3.9%, 6.6%, 32.18%, 35.40% and 77.31% respectively compared to soda pulping.
基金the National Key Research and Development Program of China(2017YFB0307900,2019YFC1905903)the National Natural Science Foundation of China(31700507)the Major Project on the Integration of Industry-Education-Research of Fujian Provincial Department of Science and Technology(2018H6003).
文摘Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.
文摘A method of treating pulpless coloured anterior tooth is presented.Most part ofthe coloured dentin of the labial crown was removed and the dental structure was bleachedwith 30% hydrogen peroxide for 5min.The pulp cavity was then filled with whitephoto-curing composite.The result of the treatment is quite satisfactory.With our treatment,the intact contour of the crown and the hardness and gloss of the enamel are preserved.SEM proved that the composite was tightly bound with the enamel of the medial wall of thepulp cavity,forming an entity with the tooth,thus guaranteeing the strength of the crown.
文摘Semaphorin 3A could be involved in angiogenesis and also enhanced bone formation was investigated in many researches. In our current study, we firstly investigated that canal obliteration might be present in some regenerative endodontic procedures cases clinically. After the establishment of the model of apical periodontitis in the maxillary first molars of rats, pulp revascularization was performed in mesial root canal. Histological sections showed that most of the tissues growing into the root canal were not real pulp tissue, but cementoid, osteoid and periodontal-like membrane. Moreover, we detected that the expression of Semaphorin 3A increased in the mesial root canal. When we used CoCl<sub>2</sub> to induce hypoxic environment, the expression of genes and proteins, Hypoxia inducible factor-1α, Vascular endothelial growth factor, and Semaphorin 3A in dental pulp stem cells were both upregulated. In conclusion, hypoxia mediated the high expression of Semaphorin 3A in DPSC might be involved tissue regeneration during pulp vascularization.
文摘Introduction: The endodontic management of necrotic permanent immature teeth is a challenge for the practitioner. These teeth are treated by apexification. However, because of the complications associated with this treatment, researchers have developed other therapies. Currently, a new technique called pulp revascularization has emerged. This technique allows the continuation of root completion thanks to a healthy tissue newly formed at the intra root canal level. Material and method: A literature search of articles dealing with pulp revascularization of immature permanent teeth was conducted using two types of search strategy, a literature search using keywords on databases and then a manual “bottom-up” search of references of previously identified articles. Results: 112 articles were identified based on inclusion and exclusion criteria. Discussion: This work showed that pulp revascularization is a new therapy that aims to restart root development on an immature permanent tooth. It is based on the principle of tissue engineering and uses the differentiation potential of stem cells. Conclusion: Currently, the literature values revascularization as it allows root development, sidewall thickening, apical closure and a decrease in periapical lesion and ensures a good sealing. Clinical and radiographic success rates appear to be encouraging, except that factors influencing treatment must be taken into consideration.
文摘Dental pulp stem cells (DPSCs) have emerged as a promising tool with greatpotential for use in tissue regeneration and engineering. Some of the mainadvantages of these cells are their multifaceted differentiation capacity, along withtheir high proliferation rate, a relative simplicity of extraction and culture thatenables obtaining patient-specific cell lines for their use in autologous celltherapy. PubMed, Scopus and Google Scholar databases were searched forrelevant articles related to the use of DPSCs in regeneration of dentin-pulpcomplex (DPC), periodontal tissues, salivary gland and craniomaxillofacial bonedefects. Few studies were found regarding the use of DPSCs for regeneration ofDPC. Scaffold-based combined with DPSCs isolated from healthy pulps was thestrategy used for DPC regeneration. Studies involved subcutaneous implantationof scaffolds loaded with DPSCs pretreated with odontogenic media, or performedon human tooth root model as a root slice. Most of the studies were related toperiodontal tissue regeneration which mainly utilized DPSCs/secretome. Forperiodontal tissues, DPSCs or their secretome were isolated from healthy orinflamed pulps and they were used either for preclinical or clinical studies.Regarding salivary gland regeneration, the submandibular gland was the onlymodel used for the preclinical studies and DPSCs or their secretome were isolatedonly from healthy pulps and they were used in preclinical studies. Likewise,DPSCs have been studied for craniomaxillofacial bone defects in the form ofmandibular, calvarial and craniofacial bone defects where DPSCs were isolatedonly from healthy pulps for preclinical and clinical studies. From the previousresults, we can conclude that DPSCs is promising candidate for dental and oraltissue regeneration.